Sample records for human migration patterns
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Directory of Open Access Journals (Sweden)
Anastasia Holobinko
2012-06-01
Full Text Available Human migration patterns are of interest to scientists representing many fields. Theories have been posited to explain modern human evolutionary expansion, the diversity of human culture, and the motivational factors underlying an individual or group decision to migrate. Although the research question and subsequent approach may vary between disciplines, one thread is ubiquitous throughout most migration studies: why do humans migrate and what is the result of such an event? While the determination of individual attributes such as age, sex, and ancestry is often integral to migration studies, the positive identification of human remains is usually irrelevant. However, the positive identification of a deceased is paramount to a forensic investigation in which human remains have been recovered and must be identified. What role, if any, might the study of human movement patterns play in the interpretation of evidence associated with unidentified human remains? Due to increasing global mobility in the world's populations, it is not inconceivable that an individual might die far away from his or her home. If positive identification cannot immediately be made, investigators may consider various theories as to how or why a deceased ended up in a particular geographic location. While scientific evidence influences the direction of forensic investigations, qualitative evaluation can be an important component of evidence interpretation. This review explores several modern human migration theories and the methodologies utilized to identify evidence of human migratory movement before addressing the practical application of migration theory to forensic cases requiring the identification of human remains.
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Directory of Open Access Journals (Sweden)
Aida T Miró-Herrans
Full Text Available Population migration has played an important role in human evolutionary history and in the patterning of human genetic variation. A deeper and empirically-based understanding of human migration dynamics is needed in order to interpret genetic and archaeological evidence and to accurately reconstruct the prehistoric processes that comprise human evolutionary history. Current empirical estimates of migration include either short time frames (i.e. within one generation or partial knowledge about migration, such as proportion of migrants or distance of migration. An analysis of migration that includes both proportion of migrants and distance, and direction over multiple generations would better inform prehistoric reconstructions. To evaluate human migration, we use GPS coordinates from the place of residence of the Yemeni individuals sampled in our study, their birthplaces and their parents' and grandparents' birthplaces to calculate the proportion of migrants, as well as the distance and direction of migration events between each generation. We test for differences in these values between the generations and identify factors that influence the probability of migration. Our results show that the proportion and distance of migration between females and males is similar within generations. In contrast, the proportion and distance of migration is significantly lower in the grandparents' generation, most likely reflecting the decreasing effect of technology. Based on our results, we calculate the proportion of migration events (0.102 and mean and median distances of migration (96 km and 26 km for the grandparent's generation to represent early times in human evolution. These estimates can serve to set parameter values of demographic models in model-based methods of prehistoric reconstruction, such as approximate Bayesian computation. Our study provides the first empirically-based estimates of human migration over multiple generations in a developing
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The use of census migration data to approximate human movement patterns across temporal scales.
Wesolowski, Amy; Buckee, Caroline O; Pindolia, Deepa K; Eagle, Nathan; Smith, David L; Garcia, Andres J; Tatem, Andrew J
2013-01-01
Human movement plays a key role in economies and development, the delivery of services, and the spread of infectious diseases. However, it remains poorly quantified partly because reliable data are often lacking, particularly for low-income countries. The most widely available are migration data from human population censuses, which provide valuable information on relatively long timescale relocations across countries, but do not capture the shorter-scale patterns, trips less than a year, that make up the bulk of human movement. Census-derived migration data may provide valuable proxies for shorter-term movements however, as substantial migration between regions can be indicative of well connected places exhibiting high levels of movement at finer time scales, but this has never been examined in detail. Here, an extensive mobile phone usage data set for Kenya was processed to extract movements between counties in 2009 on weekly, monthly, and annual time scales and compared to data on change in residence from the national census conducted during the same time period. We find that the relative ordering across Kenyan counties for incoming, outgoing and between-county movements shows strong correlations. Moreover, the distributions of trip durations from both sources of data are similar, and a spatial interaction model fit to the data reveals the relationships of different parameters over a range of movement time scales. Significant relationships between census migration data and fine temporal scale movement patterns exist, and results suggest that census data can be used to approximate certain features of movement patterns across multiple temporal scales, extending the utility of census-derived migration data.
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The use of census migration data to approximate human movement patterns across temporal scales.
Directory of Open Access Journals (Sweden)
Amy Wesolowski
Full Text Available Human movement plays a key role in economies and development, the delivery of services, and the spread of infectious diseases. However, it remains poorly quantified partly because reliable data are often lacking, particularly for low-income countries. The most widely available are migration data from human population censuses, which provide valuable information on relatively long timescale relocations across countries, but do not capture the shorter-scale patterns, trips less than a year, that make up the bulk of human movement. Census-derived migration data may provide valuable proxies for shorter-term movements however, as substantial migration between regions can be indicative of well connected places exhibiting high levels of movement at finer time scales, but this has never been examined in detail. Here, an extensive mobile phone usage data set for Kenya was processed to extract movements between counties in 2009 on weekly, monthly, and annual time scales and compared to data on change in residence from the national census conducted during the same time period. We find that the relative ordering across Kenyan counties for incoming, outgoing and between-county movements shows strong correlations. Moreover, the distributions of trip durations from both sources of data are similar, and a spatial interaction model fit to the data reveals the relationships of different parameters over a range of movement time scales. Significant relationships between census migration data and fine temporal scale movement patterns exist, and results suggest that census data can be used to approximate certain features of movement patterns across multiple temporal scales, extending the utility of census-derived migration data.
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Global spatio-temporal patterns in human migration: a complex network perspective.
Davis, Kyle F; D'Odorico, Paolo; Laio, Francesco; Ridolfi, Luca
2013-01-01
Migration is a powerful adaptive strategy for humans to navigate hardship and pursue a better quality of life. As a universal vehicle facilitating exchanges of ideas, culture, money and goods, international migration is a major contributor to globalization. Consisting of countries linked by multiple connections of human movements, global migration constitutes a network. Despite the important role of human migration in connecting various communities in different parts of the world, the topology and behavior of the international migration network and its changes through time remain poorly understood. Here we show that the global human migration network became more interconnected during the latter half of the twentieth century and that migrant destination choice partly reflects colonial and postcolonial histories, language, religion, and distances. From 1960 to 2000 we found a steady increase in network transitivity (i.e. connectivity between nodes connected to the same node), a decrease in average path length and an upward shift in degree distribution, all of which strengthened the 'small-world' behavior of the migration network. Furthermore, we found that distinct groups of countries preferentially interact to form migration communities based largely on historical, cultural and economic factors.
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Global spatio-temporal patterns in human migration: a complex network perspective.
Directory of Open Access Journals (Sweden)
Kyle F Davis
Full Text Available Migration is a powerful adaptive strategy for humans to navigate hardship and pursue a better quality of life. As a universal vehicle facilitating exchanges of ideas, culture, money and goods, international migration is a major contributor to globalization. Consisting of countries linked by multiple connections of human movements, global migration constitutes a network. Despite the important role of human migration in connecting various communities in different parts of the world, the topology and behavior of the international migration network and its changes through time remain poorly understood. Here we show that the global human migration network became more interconnected during the latter half of the twentieth century and that migrant destination choice partly reflects colonial and postcolonial histories, language, religion, and distances. From 1960 to 2000 we found a steady increase in network transitivity (i.e. connectivity between nodes connected to the same node, a decrease in average path length and an upward shift in degree distribution, all of which strengthened the 'small-world' behavior of the migration network. Furthermore, we found that distinct groups of countries preferentially interact to form migration communities based largely on historical, cultural and economic factors.
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The demographics of human and malaria movement and migration patterns in East Africa.
Pindolia, Deepa K; Garcia, Andres J; Huang, Zhuojie; Smith, David L; Alegana, Victor A; Noor, Abdisalan M; Snow, Robert W; Tatem, Andrew J
2013-11-05
The quantification of parasite movements can provide valuable information for control strategy planning across all transmission intensities. Mobile parasite carrying individuals can instigate transmission in receptive areas, spread drug resistant strains and reduce the effectiveness of control strategies. The identification of mobile demographic groups, their routes of travel and how these movements connect differing transmission zones, potentially enables limited resources for interventions to be efficiently targeted over space, time and populations. National population censuses and household surveys provide individual-level migration, travel, and other data relevant for understanding malaria movement patterns. Together with existing spatially referenced malaria data and mathematical models, network analysis techniques were used to quantify the demographics of human and malaria movement patterns in Kenya, Uganda and Tanzania. Movement networks were developed based on connectivity and magnitudes of flow within each country and compared to assess relative differences between regions and demographic groups. Additional malaria-relevant characteristics, such as short-term travel and bed net use, were also examined. Patterns of human and malaria movements varied between demographic groups, within country regions and between countries. Migration rates were highest in 20-30 year olds in all three countries, but when accounting for malaria prevalence, movements in the 10-20 year age group became more important. Different age and sex groups also exhibited substantial variations in terms of the most likely sources, sinks and routes of migration and malaria movement, as well as risk factors for infection, such as short-term travel and bed net use. Census and survey data, together with spatially referenced malaria data, GIS and network analysis tools, can be valuable for identifying, mapping and quantifying regional connectivities and the mobility of different demographic
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Visualizing Human Migration Trhough Space and Time
Zambotti, G.; Guan, W.; Gest, J.
2015-07-01
Human migration has been an important activity in human societies since antiquity. Since 1890, approximately three percent of the world's population has lived outside of their country of origin. As globalization intensifies in the modern era, human migration persists even as governments seek to more stringently regulate flows. Understanding this phenomenon, its causes, processes and impacts often starts from measuring and visualizing its spatiotemporal patterns. This study builds a generic online platform for users to interactively visualize human migration through space and time. This entails quickly ingesting human migration data in plain text or tabular format; matching the records with pre-established geographic features such as administrative polygons; symbolizing the migration flow by circular arcs of varying color and weight based on the flow attributes; connecting the centroids of the origin and destination polygons; and allowing the user to select either an origin or a destination feature to display all flows in or out of that feature through time. The method was first developed using ArcGIS Server for world-wide cross-country migration, and later applied to visualizing domestic migration patterns within China between provinces, and between states in the United States, all through multiple years. The technical challenges of this study include simplifying the shapes of features to enhance user interaction, rendering performance and application scalability; enabling the temporal renderers to provide time-based rendering of features and the flow among them; and developing a responsive web design (RWD) application to provide an optimal viewing experience. The platform is available online for the public to use, and the methodology is easily adoptable to visualizing any flow, not only human migration but also the flow of goods, capital, disease, ideology, etc., between multiple origins and destinations across space and time.
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Robotic Patterning a Superhydrophobic Surface for Collective Cell Migration Screening.
Pang, Yonggang; Yang, Jing; Hui, Zhixin; Grottkau, Brian E
2018-04-01
Collective cell migration, in which cells migrate as a group, is fundamental in many biological and pathological processes. There is increasing interest in studying the collective cell migration in high throughput. Cell scratching, insertion blocker, and gel-dissolving techniques are some methodologies used previously. However, these methods have the drawbacks of cell damage, substrate surface alteration, limitation in medium exchange, and solvent interference. The superhydrophobic surface, on which the water contact angle is greater than 150 degrees, has been recently utilized to generate patterned arrays. Independent cell culture areas can be generated on a substrate that functions the same as a conventional multiple well plate. However, so far there has been no report on superhydrophobic patterning for the study of cell migration. In this study, we report on the successful development of a robotically patterned superhydrophobic array for studying collective cell migration in high throughput. The array was developed on a rectangular single-well cell culture plate consisting of hydrophilic flat microwells separated by the superhydrophobic surface. The manufacturing process is robotic and includes patterning discrete protective masks to the substrate using 3D printing, robotic spray coating of silica nanoparticles, robotic mask removal, robotic mini silicone blocker patterning, automatic cell seeding, and liquid handling. Compared with a standard 96-well plate, our system increases the throughput by 2.25-fold and generates a cell-free area in each well non-destructively. Our system also demonstrates higher efficiency than conventional way of liquid handling using microwell plates, and shorter processing time than manual operating in migration assays. The superhydrophobic surface had no negative impact on cell viability. Using our system, we studied the collective migration of human umbilical vein endothelial cells and cancer cells using assays of endpoint
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Chagas disease, migration and community settlement patterns in Arequipa, Peru.
Directory of Open Access Journals (Sweden)
Angela M Bayer
2009-12-01
Full Text Available Chagas disease is one of the most important neglected tropical diseases in the Americas. Vectorborne transmission of Chagas disease has been historically rare in urban settings. However, in marginal communities near the city of Arequipa, Peru, urban transmission cycles have become established. We examined the history of migration and settlement patterns in these communities, and their connections to Chagas disease transmission.This was a qualitative study that employed focus group discussions and in-depth interviews. Five focus groups and 50 in-depth interviews were carried out with 94 community members from three shantytowns and two traditional towns near Arequipa, Peru. Focus groups utilized participatory methodologies to explore the community's mobility patterns and the historical and current presence of triatomine vectors. In-depth interviews based on event history calendars explored participants' migration patterns and experience with Chagas disease and vectors. Focus group data were analyzed using participatory analysis methodologies, and interview data were coded and analyzed using a grounded theory approach. Entomologic data were provided by an ongoing vector control campaign. We found that migrants to shantytowns in Arequipa were unlikely to have brought triatomines to the city upon arrival. Frequent seasonal moves, however, took shantytown residents to valleys surrounding Arequipa where vectors are prevalent. In addition, the pattern of settlement of shantytowns and the practice of raising domestic animals by residents creates a favorable environment for vector proliferation and dispersal. Finally, we uncovered a phenomenon of population loss and replacement by low-income migrants in one traditional town, which created the human settlement pattern of a new shantytown within this traditional community.The pattern of human migration is therefore an important underlying determinant of Chagas disease risk in and around Arequipa. Frequent
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Climate Vulnerability and Human Migration in Global Perspective
Grecequet, Martina; DeWaard, Jack; Hellmann, Jessica J.; Abel, Guy J.
2018-01-01
The relationship between climate change and human migration is not homogenous and depends critically on the differential vulnerability of population and places. If places and populations are not vulnerable, or susceptible, to climate change, then the climate–migration relationship may not materialize. The key to understanding and, from a policy perspective, planning for whether and how climate change will impact future migration patterns is therefore knowledge of the link between climate vulnerability and migration. However, beyond specific case studies, little is known about this association in global perspective. We therefore provide a descriptive, country-level portrait of this relationship. We show that the negative association between climate vulnerability and international migration holds only for countries least vulnerable to climate change, which suggests the potential for trapped populations in more vulnerable countries. However, when analyzed separately by life supporting sector (food, water, health, ecosystem services, human habitat, and infrastructure) and vulnerability dimension (exposure, sensitivity, and adaptive capacity), we detect evidence of a relationship among more, but not the most, vulnerable countries. The bilateral (i.e., country-to-country) migration show that, on average, people move from countries of higher vulnerability to lower vulnerability, reducing global risk by 15%. This finding is consistent with the idea that migration is a climate adaptation strategy. Still, ~6% of bilateral migration is maladaptive with respect to climate change, with some movement toward countries with greater climate change vulnerability. PMID:29707262
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Climate Vulnerability and Human Migration in Global Perspective.
Grecequet, Martina; DeWaard, Jack; Hellmann, Jessica J; Abel, Guy J
2017-05-01
The relationship between climate change and human migration is not homogenous and depends critically on the differential vulnerability of population and places. If places and populations are not vulnerable, or susceptible, to climate change, then the climate-migration relationship may not materialize. The key to understanding and, from a policy perspective, planning for whether and how climate change will impact future migration patterns is therefore knowledge of the link between climate vulnerability and migration. However, beyond specific case studies, little is known about this association in global perspective. We therefore provide a descriptive, country-level portrait of this relationship. We show that the negative association between climate vulnerability and international migration holds only for countries least vulnerable to climate change, which suggests the potential for trapped populations in more vulnerable countries. However, when analyzed separately by life supporting sector (food, water, health, ecosystem services, human habitat, and infrastructure) and vulnerability dimension (exposure, sensitivity, and adaptive capacity), we detect evidence of a relationship among more, but not the most, vulnerable countries. The bilateral (i.e., country-to-country) migration show that, on average, people move from countries of higher vulnerability to lower vulnerability, reducing global risk by 15%. This finding is consistent with the idea that migration is a climate adaptation strategy. Still, ~6% of bilateral migration is maladaptive with respect to climate change, with some movement toward countries with greater climate change vulnerability.
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Nair, Manisha; Webster, Premila
2013-03-01
About a third of the countries affected by shortage of human resources for health are the emerging market economies (EMEs). The greatest shortage in absolute terms was found to be in India and Indonesia leading to health system crisis. This review identifies the patterns of migration of health workers, causes and possible solutions in these EMEs. A qualitative synthesis approach based on the 'critical review' and 'realist review' approaches to the literature review was used. The patterns of migration of health professionals' in the EMEs have led to two types of discrepancies between health needs and healthcare workers: (i) within country (rural-urban, public-private or government healthcare sector-private sector) and (ii) across countries (south to north). Factors that influence migration include lack of employment opportunities, appropriate work environment and wages in EMEs, growing demand in high-income countries due to demographic transition, favourable country policies for financial remittances by migrant workers and medical education system of EMEs. A range of successful national and international initiatives to address health workforce migration were identified. Measures to control migration should be country specific and designed in accordance with the push and pull factors existing in the EMEs.
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Directory of Open Access Journals (Sweden)
Shymanska Kateryna V.
2017-06-01
Full Text Available The aim of the article is to reveal the influence of geo-economic transformations on the trends in international migration of human resources as an element of the resource potential of countries and regions. The current state of geo-economic transformations is analyzed, and their influence on the processes of international migration of human resources is revealed. The relevance of analyzing international movement of human resources, not labor ones, in building the geo-economic strategy of a country or a regional grouping is justified. The connection between the international migration of human resources and the trends in development of individual countries and regions (oil exporting countries, newly industrialized countries and least developed agrarian countries is determined, the general patterns of migration flows in these countries are described. Furthermore, the topical issues in studying international migration of human resources in the context of the directions of geo-economics identified by scientists are formulated. It is determined that the regional migration policy should contribute to maximizing the benefits of migration of human resources for the development of the region and the use of immigrants in the countries of the region as an economic resource that becomes strategically important under conditions of geo-economic transformations.
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Human migration, protected areas, and conservation outreach in Tanzania.
Salerno, Jonathan D; Borgerhoff Mulder, Monique; Kefauver, Shawn C
2014-06-01
A recent discussion debates the extent of human in-migration around protected areas (PAs) in the tropics. One proposed argument is that rural migrants move to bordering areas to access conservation outreach benefits. A counter proposal maintains that PAs have largely negative effects on local populations and that outreach initiatives even if successful present insufficient benefits to drive in-migration. Using data from Tanzania, we examined merits of statistical tests and spatial methods used previously to evaluate migration near PAs and applied hierarchical modeling with appropriate controls for demographic and geographic factors to advance the debate. Areas bordering national parks in Tanzania did not have elevated rates of in-migration. Low baseline population density and high vegetation productivity with low interannual variation rather than conservation outreach explained observed migration patterns. More generally we argue that to produce results of conservation policy significance, analyses must be conducted at appropriate scales, and we caution against use of demographic data without appropriate controls when drawing conclusions about migration dynamics. © 2014 Society for Conservation Biology.
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Lines of evidence for environmentally driven human migration
Davis, K. F.; D'Odorico, P.
2012-12-01
International human migration is an important mechanism that affects, and is affected by, various human and natural systems. With the number of people living outside their countries of origin currently estimated at 214 million people and projected to potentially reach more than 400 million people by mid-century, the topic of international human movements presents possible advantages and pitfalls for both sending and receiving countries on multiple fronts (e.g. economic, environmental, political and cultural). Understanding how human migration interacts with human and natural systems is therefore essential in realizing a sustainable and balanced future. While the study of international migration has historically been motivated largely by economic and political interests, the issue of environmentally induced migration has become increasingly important in light of a rapidly changing climate in conjunction with increasing population pressure on many important resources. Particularly in terms of theoretical and conceptual discussions, environmentally induced human migration has been receiving increased attention in the literature. To date, few studies - many of which focus on internal (intra-national) or regional migration - have attempted to quantify the interactions of human migration and the environment, with little attention paid to the global scale as a result of varying regional factors and lack of sufficient data. Recently available global bilateral migration datasets have been developed that allow for a more comprehensive understanding of human movements between all countries. With these datasets, we seek to elucidate environmental drivers of human migration over the past half-century using a multi-pronged approach. First, using a recently developed universal radiation model, we examine human movements based solely on global population distribution. Next, by comparison of migration movements with selected economic, environmental and human welfare indicators, we
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Some economic effects of recent migration patterns on central cities.
Sternlieb, G; Hughes, J W
1981-01-01
The authors examine demographic changes in central cities of the United States between 1970 and 1977 and the economic effects of these changes. Patterns of selective migration from central cities, particularly the general out-migration of the middle class and the recent return of the middle class to selected areas, are discussed. Changes in household and family patterns, racial composition, income, and poverty status are examined, and the aggregate impact of migration on resident incomes and purchasing power within central cities is analyzed. The findings show a continued concentration of poverty in central cities.
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Trend of different molecular markers in the last decades for studying human migrations.
Kundu, Sharbadeb; Ghosh, Sankar Kumar
2015-02-10
Anatomically modern humans are known to have widely migrated throughout history. Different scientific evidences suggest that the entire human population descended from just several thousand African migrants. About 85,000 years ago, the first wave of human migration was out of Africa, that followed the coasts through the Middle East, into Southern Asia via Sri Lanka, and in due course around Indonesia and into Australia. Another wave of migration between 40,000 and 12,000 years ago brought humans northward into Europe. However, the frozen north limited human expansion in Europe, and created a land bridge, "Bering land bridge", connecting Asia with North America about 25,000 years ago. Although fossil data give the most direct information about our past, it has certain anomalies. So, molecular archeologists are now using different molecular markers to trace the "most recent common ancestor" and also the migration pattern of modern humans. In this study, we have studied the trend of molecular markers and also the methodologies implemented in the last decades (2003-2014). From our observation, we can say that D-loop region of mtDNA and Y chromosome based markers are predominant. Nevertheless, mtDNA, especially the D-loop region, has some unique features, which makes it a more effective marker for tracing prehistoric footprints of modern human populations. Although, natural selection should also be taken into account in studying mtDNA based human migration. As per technology is concerned, Sanger sequencing is the major technique that is being used in almost all studies. But, the emergence of different cost-effective-and-easy-to-handle NGS platforms has increased its popularity over Sanger sequencing in studying human migration. Copyright © 2014. Published by Elsevier B.V.
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Migration and persistence of human influenza A viruses, Vietnam, 2001-2008.
Le, Mai Quynh; Lam, Ha Minh; Cuong, Vuong Duc; Lam, Tommy Tsan-Yuk; Halpin, Rebecca A; Wentworth, David E; Hien, Nguyen Tran; Thanh, Le Thi; Phuong, Hoang Vu Mai; Horby, Peter; Boni, Maciej F
2013-11-01
Understanding global influenza migration and persistence is crucial for vaccine strain selection. Using 240 new human influenza A virus whole genomes collected in Vietnam during 2001-2008, we looked for persistence patterns and migratory connections between Vietnam and other countries. We found that viruses in Vietnam migrate to and from China, Hong Kong, Taiwan, Cambodia, Japan, South Korea, and the United States. We attempted to reduce geographic bias by generating phylogenies subsampled at the year and country levels. However, migration events in these phylogenies were still driven by the presence or absence of sequence data, indicating that an epidemiologic study design that controls for prevalence is required for robust migration analysis. With whole-genome data, most migration events are not detectable from the phylogeny of the hemagglutinin segment alone, although general migratory relationships between Vietnam and other countries are visible in the hemagglutinin phylogeny. It is possible that virus lineages in Vietnam persisted for >1 year.
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Spatial pattern analysis of nuclear migration in remodelled muscles during Drosophila metamorphosis.
Kuleesha; Feng, Lin; Wasser, Martin
2017-07-10
Many human muscle wasting diseases are associated with abnormal nuclear localization. During metamorphosis in Drosophila melanogaster, multi-nucleated larval dorsal abdominal muscles either undergo cell death or are remodeled to temporary adult muscles. Muscle remodeling is associated with anti-polar nuclear migration and atrophy during early pupation followed by polar migration and muscle growth during late pupation. Muscle remodeling is a useful model to study genes involved in myonuclear migration. Previously, we showed that loss of Cathepsin-L inhibited anti-polar movements, while knockdown of autophagy-related genes affected nuclear positioning along the medial axis in late metamorphosis. To compare the phenotypic effects of gene perturbations on nuclear migration more objectively, we developed new descriptors of myonuclear distribution. To obtain nuclear pattern features, we designed an algorithm to detect and track nuclear regions inside live muscles. Nuclear tracks were used to distinguish between fast moving nuclei associated with fragments of dead muscles (sarcolytes) and slow-moving nuclei inside remodelled muscles. Nuclear spatial pattern features, such as longitudinal (lonNS) and lateral nuclear spread (latNS), allowed us to compare nuclear migration during muscle remodelling in different genetic backgrounds. Anti-polar migration leads to a lonNS decrease. As expected, lack of myonuclear migration caused by the loss of Cp1 was correlated with a significantly lower lonNS decrease. Unexpectedly, the decrease in lonNS was significantly enhanced by Atg9, Atg5 and Atg18 silencing, indicating that the loss of autophagy promotes the migration and clustering of nuclei. Loss of autophagy also caused a scattering of nuclei along the lateral axis, leading to a two-row as opposed to single row distribution in control muscles. Increased latNS resulting from knockdown of Atg9 and Atg18 was correlated with increased muscle diameter, suggesting that the wider muscle
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[Migration patterns of health professionals].
Kingma, Mireille
2005-01-01
The past three decades have seen the number of international migrants double, to reach the unprecedented total of 175 million people in 2003. National health systems are often the biggest national employer, responsible for an estimated 35 million workers worldwide. Health professionals are part of the expanding global labour market. Today, foreign-educated health professionals represent more than a quarter of the medical and nursing workforces of Australia, Canada, the United Kingdom and the United States. Destination countries, however, are not limited to industrialised nations. For example, 50 per cent of physicians in the Namibia public services are expatriates and South Africa continues to recruit close to 80% of its rural physicians from other countries. International migration often imitates patterns of internal migration. The exodus from rural to urban areas, from lower to higher income urban neighbourhoods and from lower-income to higher-income sectors contributes challenges to the universal coverage of the population. International migration is often blamed for the dramatic health professional shortages witnessed in the developing countries. A recent OECD study, however, concludes that many registered nurses in South Africa (far exceeding the number that emigrate) are either inactive or unemployed. These dire situations constitute a modern paradox which is for the most part ignored. Shared language, promises of a better quality of life and globalization all support the continued existence of health professionals' international migration. The ethical dimension o this mobility is a sensitive issue that needs to be addressed. A major paradigm shift, however, is required in order to lessen the need to migrate rather than artificially curb the flows.
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EMPIRICAL REFLECTIONS ON MIGRATION PHENOMENON. MAJOR EFFECTS OF MIGRATION ON THE HUMAN CAPITAL
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Simona BUTA
2013-12-01
Full Text Available The paper Empirical reflections on migration phenomenon. Major effects of migration on the human capital analyzes the migration flows of the workforce (as part of the human capital globally/regionally, especially the highly qualified workforce migration. The qualified manpower processes of attracting on the work market have not been always well understood and, in some cases, have generated a series of difficulties. This is the reason why we will focus on the „waste of brains” phenomenon, which appears when highly qualified individuals are neither employed in the source-country nor in the target country; and, if they are, their job is below their qualifications.
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In vitro human keratinocyte migration rates are associated with SNPs in the KRT1 interval.
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Heng Tao
Full Text Available Efforts to develop effective therapeutic treatments for promoting fast wound healing after injury to the epidermis are hindered by a lack of understanding of the factors involved. Re-epithelialization is an essential step of wound healing involving the migration of epidermal keratinocytes over the wound site. Here, we examine genetic variants in the keratin-1 (KRT1 locus for association with migration rates of human epidermal keratinocytes (HEK isolated from different individuals. Although the role of intermediate filament genes, including KRT1, in wound activated keratinocytes is well established, this is the first study to examine if genetic variants in humans contribute to differences in the migration rates of these cells. Using an in vitro scratch wound assay we observe quantifiable variation in HEK migration rates in two independent sets of samples; 24 samples in the first set and 17 samples in the second set. We analyze genetic variants in the KRT1 interval and identify SNPs significantly associated with HEK migration rates in both samples sets. Additionally, we show in the first set of samples that the average migration rate of HEK cells homozygous for one common haplotype pattern in the KRT1 interval is significantly faster than that of HEK cells homozygous for a second common haplotype pattern. Our study demonstrates that genetic variants in the KRT1 interval contribute to quantifiable differences in the migration rates of keratinocytes isolated from different individuals. Furthermore we show that in vitro cell assays can successfully be used to deconstruct complex traits into simple biological model systems for genetic association studies.
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Reconstructing the migration patterns of late Pleistocene mammals from northern Florida, USA
Hoppe, Kathryn A.; Koch, Paul L.
2007-11-01
We used analyses of the strontium isotope ( 87Sr/ 86Sr) ratios of tooth enamel to reconstruct the migration patterns of fossil mammals collected along the Aucilla River in northern Florida. Specimens date to the late-glacial period and before the last glacial maximum (pre-LGM). Deer and tapir displayed low 87Sr/ 86Sr ratios that were similar to the ratios of Florida environments, which suggest that these taxa did not migrate long distance outside of the Florida region. Mastodons, mammoths, and equids all displayed a wide range of 87Sr/ 86Sr ratios. Some individuals in each taxon displayed low 87Sr/ 86Sr ratios that suggest they ranged locally, while other animals had high 87Sr/ 86Sr ratios that suggest they migrated long distances (> 150 km) outside of the Florida region. Mastodons were the only taxa from this region that provided enough well-dated specimens to compare changes in migration patterns over time. Pre-LGM mastodons displayed significantly lower 87Sr/ 86Sr ratios than late-glacial mastodons, which suggests that late-glacial mastodons from Florida migrated longer distances than their earlier counterparts. This change in movement patterns reflects temporal changes in regional vegetation patterns.
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Migration and Persistence of Human Influenza A Viruses, Vietnam, 2001–2008
Le, Mai Quynh; Lam, Ha Minh; Cuong, Vuong Duc; Lam, Tommy Tsan-Yuk; Halpin, Rebecca A; Wentworth, David E; Hien, Nguyen Tran; Thanh, Le Thi; Phuong, Hoang Vu Mai; Horby, Peter
2013-01-01
Understanding global influenza migration and persistence is crucial for vaccine strain selection. Using 240 new human influenza A virus whole genomes collected in Vietnam during 2001–2008, we looked for persistence patterns and migratory connections between Vietnam and other countries. We found that viruses in Vietnam migrate to and from China, Hong Kong, Taiwan, Cambodia, Japan, South Korea, and the United States. We attempted to reduce geographic bias by generating phylogenies subsampled at the year and country levels. However, migration events in these phylogenies were still driven by the presence or absence of sequence data, indicating that an epidemiologic study design that controls for prevalence is required for robust migration analysis. With whole-genome data, most migration events are not detectable from the phylogeny of the hemagglutinin segment alone, although general migratory relationships between Vietnam and other countries are visible in the hemagglutinin phylogeny. It is possible that virus lineages in Vietnam persisted for >1 year. PMID:24188643
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Sovereignty, human rights, and international migrations
Directory of Open Access Journals (Sweden)
Rossana Rocha Reis
2006-01-01
Full Text Available This article discusses the relationship between sovereignty and human rights concerning the elaboration of immigration policies. It deals with the role of the State in international migrations, the effects of the development of an international human rights legislation over the immigration question, and finally discusses the idea that the increasing international migration is leading the State to lose control over its population and territory, two central features of the sovereignty concept.
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Rainfall Patterns and U.S. Migration from Rural Mexico
Hunter, Lori M.; Murray, Sheena; Riosmena, Fernando
2014-01-01
In many rural regions of developing countries, natural resource dependency means changes in climate patterns hold tremendous potential to impact livelihoods. When environmentally-based livelihood options are constrained, migration can become an important adaptive strategy. Using data from the Mexican Migration Project, we model U.S. emigration from rural communities as related to community, household and climate factors. The results suggest that households subjected to recent drought conditions are far more likely to send a U.S. migrant, but only in communities with strong migration histories. In regions lacking such social networks, rainfall deficits actually reduce migration propensities, perhaps reflecting constraints in the ability to engage in migration as a coping strategy. Policy implications emphasize diversification of rural Mexican livelihoods in the face of contemporary climate change. PMID:25473143
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Patsialou, Antonia; Bravo-Cordero, Jose Javier; Wang, Yarong; Entenberg, David; Liu, Huiping; Clarke, Michael; Condeelis, John S.
2014-01-01
Metastasis is the main cause of death in breast cancer patients. Cell migration is an essential component of almost every step of the metastatic cascade, especially the early step of invasion inside the primary tumor. In this report, we have used intravital multiphoton microscopy to visualize the different migration patterns of human breast tumor cells in live primary tumors. We used xenograft tumors of MDA-MB-231 cells as well as a low passage xenograft tumor from orthotopically injected patient-derived breast tumor cells. Direct visualization of human tumor cells in vivo shows two patterns of high-speed migration inside primary tumors: a. single cells and b. multicellular streams (i.e., cells following each other in a single file but without cohesive cell junctions). Critically, we found that only streaming and not random migration of single cells was significantly correlated with proximity to vessels, with intravasation and with numbers of elevated circulating tumor cells in the bloodstream. Finally, although the two human tumors were derived from diverse genetic backgrounds, we found that their migratory tumor cells exhibited coordinated gene expression changes that led to the same end-phenotype of enhanced migration involving activating actin polymerization and myosin contraction. Our data are the first direct visualization and assessment of in vivo migration within a live patient-derived breast xenograft tumor. PMID:25013744
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Agricultural activity shapes the communication and migration patterns in Senegal
Martin-Gutierrez, S.; Borondo, J.; Morales, A. J.; Losada, J. C.; Tarquis, A. M.; Benito, R. M.
2016-06-01
The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this paper, we use mobile phone records to explore the impact of agricultural activity on the communication and mobility patterns of the inhabitants of Senegal. We find two peaks of phone calls activity emerging during the growing season. Moreover, during the harvest period, we detect an increase in the migration flows throughout the country. However, religious holidays also shape the mobility patterns of the Senegalese people. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country.
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Glia maturation factor gamma regulates the migration and adherence of human T lymphocytes
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Lippert Dustin ND
2012-04-01
Full Text Available Abstract Background Lymphocyte migration and chemotaxis are essential for effective immune surveillance. A critical aspect of migration is cell polarization and the extension of pseudopodia in the direction of movement. However, our knowledge of the underlying molecular mechanisms responsible for these events is incomplete. Proteomic analysis of the isolated leading edges of CXCL12 stimulated human T cell lines was used to identify glia maturation factor gamma (GMFG as a component of the pseudopodia. This protein is predominantly expressed in hematopoietic cells and it has been shown to regulate cytoskeletal branching. The present studies were undertaken to examine the role of GMFG in lymphocyte migration. Results Microscopic analysis of migrating T-cells demonstrated that GMFG was distributed along the axis of movement with enrichment in the leading edge and behind the nucleus of these cells. Inhibition of GMFG expression in T cell lines and IL-2 dependent human peripheral blood T cells with shRNAmir reduced cellular basal and chemokine induced migration responses. The failure of the cells with reduced GMFG to migrate was associated with an apparent inability to detach from the substrates that they were moving on. It was also noted that these cells had an increased adherence to extracellular matrix proteins such as fibronectin. These changes in adherence were associated with altered patterns of β1 integrin expression and increased levels of activated integrins as detected with the activation specific antibody HUTS4. GMFG loss was also shown to increase the expression of the β2 integrin LFA-1 and to increase the adhesion of these cells to ICAM-1. Conclusions The present studies demonstrate that GMFG is a component of human T cell pseudopodia required for migration. The reduction in migration and increased adherence properties associated with inhibition of GMFG expression suggest that GMFG activity influences the regulation of integrin mediated
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Study of health human resource migration in India
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Panneer Sigamani
2015-01-01
Full Text Available Background Human Resource for Health (HRH migration is an emerging concern in the development paradigm due to the critical importance to sustainability of health system in India. Being the largest human resource supplier to the world, it is important to analyze the consequences of the migration of HRH in the delivery of healthcare services to the country’s population. The study evidences limited to examine the size, distribution of the existing human resources or trends or patterns in migration. The consequences of migration have its implications to the healthcare delivery mechanism which needed to be critically analyzed. Review Methodology The methodology adopted in the paper is descriptive design. The critical review used to evaluate the existing evidence and to develop conceptual framework. The process involved the setting of the inclusion and exclusion criteria to select the articles. It included wide range of articles from the world development reports to specific studies oriented on the HRH scenario of the country. The search strategy comprised both form of studies qualitative and quantitative. The study utilizes the official data set published as report form. Main Findings The data on the migration in context of India, not systematically updated in the existing evidences. The availability of data on migration limits to few reports i.e.(World Health Organization WHO’s Joint Learning Initiatives and studies which combines census data of Organization for Economic Cooperation and Development (OECD and results in the number of foreign born health professionals. 1. A major proportion of the research studies reviewed describes the disparity in distribution of HRH between rural-urban and public-private. Few researches focused towards the policy environment of the source and destination country for the migration. 2. There is pool of literature explaining the factors of migration but it margins when to analyze the significant implications to
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Patterns of gravity induced aggregate migration during casting of fluid concretes
DEFF Research Database (Denmark)
Spangenberg, Jon; Roussel, N.; Hattel, Jesper Henri
2012-01-01
In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in...
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Athukorala, P
1993-11-01
"This paper reviews the literature on international labour migration from and within the Asian-Pacific region. It deals with patterns and characteristics of migration flows, government policies towards labour migration, and economic implications of labour migration for both labour-exporting and importing countries in the region. The indications are that, despite gradual slowing down of labour flows to the western industrial countries and the Middle East, labour migration will continue to be a major economic influence on surplus-labour countries in the region. As an integral part of the growth dynamism in the region, labour migration has now begun to take on a regional dimension, with immense implications for the process of industrial restructuring in high growth economies and the changing pattern of economic interdependence among countries." excerpt
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The Inuit cancer pattern--the influence of migration
DEFF Research Database (Denmark)
Boysen, T.; Friborg, J.; Andersen, Allan
2008-01-01
The Inuit cancer pattern is characterized by high frequencies of Epstein-Barr Virus (EBV)-associated carcinomas of the nasopharynx and salivary glands. The reasons are unknown, but genetic and environmental factors are believed to be involved. Using data from the well-defined Inuit population...... following migration to Denmark. The SIR was not generally influenced by duration of stay. The high risk of carcinoma of the nasopharynx and salivary glands observed in Inuit populations is maintained after migration to a low incidence area. This indicates that genetic factors or environmental factors acting...
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Thalidomide increases human keratinocyte migration and proliferation.
Nasca, M R; O'Toole, E A; Palicharla, P; West, D P; Woodley, D T
1999-11-01
Thalidomide is reported to have therapeutic utility in the treatment of pyoderma gangrenosum, Behçet's disease, aphthous ulcers, and skin wounds. We investigated the effect of thalidomide on human keratinocyte proliferation and migration, two early and critical events in the re-epithelialization of skin wounds. Thalidomide at concentrations less than 1 microM did not affect keratinocyte viability. Using a thymidine incorporation assay, we found that thalidomide, at therapeutic concentrations, induced more than a 2. 5-fold increase in the proliferative potential of the cells. Keratinocyte migration was assessed by two independent motility assays: a colloidal gold assay and an in vitro scratch assay. At optimal concentrations, thalidomide increased keratinocyte migration on a collagen matrix more than 2-fold in the colloidal gold assay and more than 3-fold in the scratch assay over control. Although pro-migratory, thalidomide did not alter the level of metalloproteinase-9 secreted into culture medium. Thalidomide did, however, induce a 2-4-fold increase in keratinocyte-derived interleukin-8, a pro-migratory cellular autocrine factor. Human keratinocyte migration and proliferation are essential for re-epithelialization of skin wounds. Interleukin-8 increases human keratinocyte migration and proliferation and is chemotactic for keratinocytes. Therefore, thalidomide may modulate keratinocyte proliferation and motility by a chemokine-dependent pathway.
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Directory of Open Access Journals (Sweden)
Kristopher P Croome
Full Text Available Traveling to seek specialized care such as liver transplantation (LT is a reality in the United States. Patient migration has been attributed to organ availability. The aims of this study were to delineate patterns of patient migration and outcomes after LT.All deceased donor LT between 2008-2013 were extracted from UNOS data. Migrated patients were defined as those patients who underwent LT at a center in a different UNOS region from the region in which they resided and traveled a distance > 100 miles.Migrated patients comprised 8.2% of 28,700 LT performed. Efflux and influx of patients were observed in all 11 UNOS regions. Regions 1, 5, 6, and 9 had a net efflux, while regions 2, 3, 4, 7, 10, and 11 had a net influx of patients. After multivariate adjustment for donor and recipient factors, graft (p = 0.68 and patient survival (p = 0.52 were similar between migrated and non-migrated patients.A significant number of patients migrated in patterns that could not be explained alone by regional variations in MELD score and wait time. Migration may be a complex interplay of factors including referral patterns, specialized services at centers of excellence and patient preference.
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Migration history of air-breathing fishes reveals Neogene atmospheric circulation patterns
Böhme, M.
2004-05-01
The migration history of an air-breathing fish group (Channidae; snakehead fishes) is used for reconstructing Neogene Eurasian precipitation and atmospheric circulation patterns. The study shows that snakeheads are sensitive indicators of summer precipitation maxima in subtropical and temperate regions, and are present regularly if the wettest month exceeds 150 mm precipitation and 20 °C mean temperature. The analysis of 515 fossil freshwater fish deposits of the past 50 m.y. from Africa and Eurasia shows two continental-scale migration events from the snakeheads' center of origin in the south Himalayan region, events that can be related to changes in the Northern Hemisphere circulation pattern. The first migration, ca. 17.5 Ma, into western and central Eurasia may have been caused by a northward shift of the Intertropical Convergence Zone that brought western Eurasia under the influence of trade winds that produced a zonal and meridional precipitation gradient in Europe. During the second migration, between 8 and 4 Ma, into Africa and East Asia, snakeheads reached their present-day distribution. This migration could have been related to the intensification of the Asian monsoon that brought summer precipitation to their migratory pathways in East Africa Arabia and East Asia.
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Does human migration affect international trade? A complex-network perspective.
Fagiolo, Giorgio; Mastrorillo, Marina
2014-01-01
This paper explores the relationships between international human migration and merchandise trade, using a complex-network approach. We firstly compare the topological structure of worldwide networks of human migration and bilateral trade over the period 1960-2000. Next, we ask whether the position of any pair of countries in the migration network affects their bilateral trade flows. We show that: (i) both weighted and binary versions of the networks of international migration and trade are strongly correlated; (ii) such correlations can be mostly explained by country economic/demographic size and geographical distance; and (iii) pairs of countries that are more central in the international-migration network trade more. Our findings suggest that bilateral trade between any two countries is not only affected by the presence of migrants from either countries but also by their relative embeddedness in the complex web of corridors making up the network of international human migration.
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Does human migration affect international trade? A complex-network perspective.
Directory of Open Access Journals (Sweden)
Giorgio Fagiolo
Full Text Available This paper explores the relationships between international human migration and merchandise trade, using a complex-network approach. We firstly compare the topological structure of worldwide networks of human migration and bilateral trade over the period 1960-2000. Next, we ask whether the position of any pair of countries in the migration network affects their bilateral trade flows. We show that: (i both weighted and binary versions of the networks of international migration and trade are strongly correlated; (ii such correlations can be mostly explained by country economic/demographic size and geographical distance; and (iii pairs of countries that are more central in the international-migration network trade more. Our findings suggest that bilateral trade between any two countries is not only affected by the presence of migrants from either countries but also by their relative embeddedness in the complex web of corridors making up the network of international human migration.
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Protected areas as frontiers for human migration.
Zommers, Zinta; MacDonald, David W
2012-06-01
Causes of human population growth near protected areas have been much debated. We conducted 821 interviews in 16 villages around Budongo Forest Reserve, Masindi district, Uganda, to explore the causes of human migration to protected areas and to identify differences in forest use between migrant and nonmigrant communities. We asked subjects for information about birthplace, migration, household assets, household activities, and forest use. Interview subjects were categorized as nonmigrants (born in one of the interview villages), socioeconomic migrants (chose to emigrate for economic or social reasons) from within Masindi district (i.e., local migrants) and from outside the Masindi district (i.e., regional migrants), or forced migrants (i.e., refugees or internally displaced individuals who emigrated as a result of conflict, human rights abuses, or natural disaster). Only 198 respondents were born in interview villages, indicating high rates of migration between 1998 and 2008. Migrants were drawn to Budongo Forest because they thought land was available (268 individuals) or had family in the area (161 individuals). A greater number of regional migrants settled in villages near Lake Albert than did forced and local migrants. Migration category was also associated with differences in sources of livelihood. Of forced migrants 40.5% earned wages through labor, whereas 25.5% of local and 14.5% of regional migrants engaged in wage labor. Migrant groups appeared to have different effects on the environment. Of respondents that hunted, 72.7% were regional migrants. Principal component analyses indicated households of regional migrants were more likely to be associated with deforestation. Our results revealed gaps in current models of human population growth around protected areas. By highlighting the importance of social networks and livelihood choices, our results contribute to a more nuanced understanding of causes of migration and of the environmental effects of
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Human neutrophils facilitate tumor cell transendothelial migration.
LENUS (Irish Health Repository)
Wu, Q D
2012-02-03
Tumor cell extravasation plays a key role in tumor metastasis. However, the precise mechanisms by which tumor cells migrate through normal vascular endothelium remain unclear. In this study, using an in vitro transendothelial migration model, we show that human polymorphonuclear neutrophils (PMN) assist the human breast tumor cell line MDA-MB-231 to cross the endothelial barrier. We found that tumor-conditioned medium (TCM) downregulated PMN cytocidal function, delayed PMN apoptosis, and concomitantly upregulated PMN adhesion molecule expression. These PMN treated with TCM attached to tumor cells and facilitated tumor cell migration through different endothelial monolayers. In contrast, MDA-MB-231 cells alone did not transmigrate. FACScan analysis revealed that these tumor cells expressed high levels of intercellular adhesion molecule-1 (ICAM-1) but did not express CD11a, CD11b, or CD18. Blockage of CD11b and CD18 on PMN and of ICAM-1 on MDA-MB-231 cells significantly attenuated TCM-treated, PMN-mediated tumor cell migration. These tumor cells still possessed the ability to proliferate after PMN-assisted transmigration. These results indicate that TCM-treated PMN may serve as a carrier to assist tumor cell transendothelial migration and suggest that tumor cells can exploit PMN and alter their function to facilitate their extravasation.
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Lesion-induced increase in survival and migration of human neural progenitor cells releasing GDNF
Behrstock, Soshana; Ebert, Allison D.; Klein, Sandra; Schmitt, Melanie; Moore, Jeannette M.; Svendsen, Clive N.
2009-01-01
The use of human neural progenitor cells (hNPC) has been proposed to provide neuronal replacement or astrocytes delivering growth factors for brain disorders such as Parkinson’s and Huntington’s disease. Success in such studies likely requires migration from the site of transplantation and integration into host tissue in the face of ongoing damage. In the current study, hNPC modified to release glial cell line derived neurotrophic factor (hNPCGDNF) were transplanted into either intact or lesioned animals. GDNF release itself had no effect on the survival, migration or differentiation of the cells. The most robust migration and survival was found using a direct lesion of striatum (Huntington’s model) with indirect lesions of the dopamine system (Parkinson’s model) or intact animals showing successively less migration and survival. No lesion affected differentiation patterns. We conclude that the type of brain injury dictates migration and integration of hNPC which has important consequences when considering transplantation of these cells as a therapy for neurodegenerative diseases. PMID:19044202
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Analysis on the Changing Spatial Patterns of China's Migration in 1985-2010
Zan, Q.; Bian, Y.
2014-11-01
Based on the data of China's fourth, fifth and sixth population census, taking the seven geographical zone as research units, the Changing Spatial Patterns of China's Migration in 1985-2010 is studied by the means of spatial analysis and mathematical statistics. The empirical results show that: (1) The migration population in China was increasing a lot in 1985-2010, and the main part of it is Provincial migration. (2) The total number of migration, immigration and emigration, the relative proportion of inter provincial and provincial migration have been positively correlated to the regional economic development level. (3) The emigrations from Hong Kong, Macao, Taiwan and overseas mainly moved to East and North China. (4) Central and west of China are the main area where people outflowed from, and most migration population moved to south-eastern coastal areas. The migration in Northeast and northwest of China is still relatively small. The main direction of population migration and flowing is from west to east and from north to south.
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Zenzal, Theodore J; Contina, Andrea J; Kelly, Jeffrey F; Moore, Frank R
2018-01-01
Autumn latitudinal migrations generally exhibit one of two different temporal migration patterns: type 1 where southern populations migrate south before northern populations, or type 2 where northern populations overtake southern populations en route . The ruby-throated hummingbird ( Archilochus colubris ) is a species with an expansive breeding range, which allows opportunities to examine variation in the timing of migration. Our objective was to determine a relationship between natal origin of ruby-throated hummingbirds and arrival at a Gulf coast stopover site; and if so, what factors, such as differences in body size across the range as well as the cost of migration, might drive such a pattern. To carry out our objectives, we captured hummingbirds at a coastal stopover site during autumn migration, at which time we collected feathers from juveniles for analysis of hydrogen stable isotopes. Using the hydrogen stable isotope gradient of precipitation across North America and published hydrogen isotope values of feathers from populations of breeding ruby-throated hummingbirds, we assigned migrants to probable natal latitudes. Our results confirm that individuals from across the range (30-50° N) stopover along the Gulf of Mexico and there is a positive relationship between arrival day and latitude, suggesting a type 1 migration pattern. We also found no relationship between fuel load (proxy for migration cost) or fat-free body mass (proxy for body size) and natal latitude. Our results, coupled with previous work on the spatial migration patterns of hummingbirds, show a type 1 chain migration pattern. While the mechanisms we tested do not seem to influence the evolution of migratory patterns, other factors such as resource availability may play a prominent role in the evolution of this migration system.
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The genetic signature of sex-biased migration in patrilocal chimpanzees and humans.
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Kevin E Langergraber
Full Text Available A large body of theoretical work suggests that analyses of variation at the maternally inherited mitochondrial (mtDNA and the paternally inherited non-recombining portion of the Y chromosome (NRY are a potentially powerful way to reveal the differing migratory histories of men and women across human societies. However, the few empirical studies comparing mtDNA and NRY variation and known patterns of sex-biased migration have produced conflicting results. Here we review some methodological reasons for these inconsistencies, and take them into account to provide an unbiased characterization of mtDNA and NRY variation in chimpanzees, one of the few mammalian taxa where males routinely remain in and females typically disperse from their natal groups. We show that patterns of mtDNA and NRY variation are more strongly contrasting in patrilocal chimpanzees compared with patrilocal human societies. The chimpanzee data we present here thus provide a valuable comparative benchmark of the patterns of mtDNA and NRY variation to be expected in a society with extremely female-biased dispersal.
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Population Dynamics of Early Human Migration in Britain.
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Mayank N Vahia
Full Text Available Early human migration is largely determined by geography and human needs. These are both deterministic parameters when small populations move into unoccupied areas where conflicts and large group dynamics are not important. The early period of human migration into the British Isles provides such a laboratory which, because of its relative geographical isolation, may allow some insights into the complex dynamics of early human migration and interaction.We developed a simulation code based on human affinity to habitable land, as defined by availability of water sources, altitude, and flatness of land, in choosing the path of migration. Movement of people on the British island over the prehistoric period from their initial entry points was simulated on the basis of data from the megalithic period. Topographical and hydro-shed data from satellite databases was used to define habitability, based on distance from water bodies, flatness of the terrain, and altitude above sea level. We simulated population movement based on assumptions of affinity for more habitable places, with the rate of movement tempered by existing populations. We compared results of our computer simulations with genetic data and show that our simulation can predict fairly accurately the points of contacts between different migratory paths. Such comparison also provides more detailed information about the path of peoples' movement over ~2000 years before the present era.We demonstrate an accurate method to simulate prehistoric movements of people based upon current topographical satellite data. Our findings are validated by recently-available genetic data. Our method may prove useful in determining early human population dynamics even when no genetic information is available.
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McCloskey, Sarah E.; Uher-Koch, Brian D.; Schmutz, Joel A.; Fondell, Thomas F.
2018-01-01
Identifying post-breeding migration and wintering distributions of migratory birds is important for understanding factors that may drive population dynamics. Red-throated Loons (Gavia stellata) are widely distributed across Alaska and currently have varying population trends, including some populations with recent periods of decline. To investigate population differentiation and the location of migration pathways and wintering areas, which may inform population trend patterns, we used satellite transmitters (n = 32) to describe migration patterns of four geographically separate breeding populations of Red-throated Loons in Alaska. On average (± SD) Red-throated Loons underwent long (6,288 ± 1,825 km) fall and spring migrations predominantly along coastlines. The most northern population (Arctic Coastal Plain) migrated westward to East Asia and traveled approximately 2,000 km farther to wintering sites than the three more southerly populations (Seward Peninsula, Yukon-Kuskokwim Delta, and Copper River Delta) which migrated south along the Pacific coast of North America. These migration paths are consistent with the hypothesis that Red-throated Loons from the Arctic Coastal Plain are exposed to contaminants in East Asia. The three more southerly breeding populations demonstrated a chain migration pattern in which the more northerly breeding populations generally wintered in more northerly latitudes. Collectively, the migration paths observed in this study demonstrate that some geographically distinct breeding populations overlap in wintering distribution while others use highly different wintering areas. Red-throated Loon population trends in Alaska may therefore be driven by a wide range of effects throughout the annual cycle.
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Directory of Open Access Journals (Sweden)
Dongyuan Lü
Full Text Available Keratinocyte migration during re-epithelization is crucial in wound healing under biochemical and biomechanical microenvironment. However, little is known about the underlying mechanisms whereby mechanical tension and cocultured fibroblasts or keratinocytes modulate the migration of keratinocytes or fibroblasts. Here we applied a tensile device together with a modified transwell assay to determine the lateral and transmembrane migration dynamics of human HaCaT keratinocytes or HF fibroblasts. A novel pattern of asymmetric migration was observed for keratinocytes when they were cocultured with non-contact fibroblasts, i.e., the accumulative distance of HaCaT cells was significantly higher when moving away from HF cells or migrating from down to up cross the membrane than that when moving close to HF cells or when migrating from up to down, whereas HF migration was symmetric. This asymmetric migration was mainly regulated by EGF derived from fibroblasts, but not transforming growth factor α or β1 production. Mechanical stretch subjected to fibroblasts fostered keratinocyte asymmetric migration by increasing EGF secretion, while no role of mechanical stretch was found for EGF secretion by keratinocytes. These results provided a new insight into understanding the regulating mechanisms of two- or three-dimensional migration of keratinocytes or fibroblasts along or across dermis and epidermis under biomechanical microenvironment.
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Directory of Open Access Journals (Sweden)
Carren Ginsburg
2016-05-01
Full Text Available Background: Education, as a key indicator of human capital, is considered one of the major determinants of internal migration, with previous studies suggesting that human capital accumulates in urban areas at the expense of rural areas. However, there is fragmentary evidence concerning the educational correlates of internal migration in sub-Saharan Africa. Objective: The study questions whether more precise measures of migration in Health and Demographic Surveillance System (HDSS populations support the hypothesis that migrants are self-selected on human capital and more educated people are more likely to leave rural areas or enter urban areas within a geographical region. Methods: Using unique longitudinal data representing approximately 900,000 people living in eight sub-Saharan African HDSS sites that are members of the INDEPTH Network, the paper uses Event History Analysis techniques to examine the relationship between formal educational attainment and in- and out-migration, over the period 2009 to 2011. Results: Between 7Š and 27Š of these local populations are moving in or out of the HDSS area over this period. Education is positively associated with both in- and out-migration in the Kenyan HDSS areas; however, the education effect has no clear pattern in the HDSS sites in Burkina Faso, Mozambique, and South Africa. Conclusions: Empirical results presented in this paper confirm a strong age profile of migration consistent with human capital expectation, yet the results point to variability in the association of education and the propensity to migrate. In particular, the hypothesis of a shift of human capital from rural to urban areas is not universally valid.
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Ordered patterns of cell shape and orientational correlation during spontaneous cell migration.
Directory of Open Access Journals (Sweden)
Yusuke T Maeda
Full Text Available BACKGROUND: In the absence of stimuli, most motile eukaryotic cells move by spontaneously coordinating cell deformation with cell movement in the absence of stimuli. Yet little is known about how cells change their own shape and how cells coordinate the deformation and movement. Here, we investigated the mechanism of spontaneous cell migration by using computational analyses. METHODOLOGY: We observed spontaneously migrating Dictyostelium cells in both a vegetative state (round cell shape and slow motion and starved one (elongated cell shape and fast motion. We then extracted regular patterns of morphological dynamics and the pattern-dependent systematic coordination with filamentous actin (F-actin and cell movement by statistical dynamic analyses. CONCLUSIONS/SIGNIFICANCE: We found that Dictyostelium cells in both vegetative and starved states commonly organize their own shape into three ordered patterns, elongation, rotation, and oscillation, in the absence of external stimuli. Further, cells inactivated for PI3-kinase (PI3K and/or PTEN did not show ordered patterns due to the lack of spatial control in pseudopodial formation in both the vegetative and starved states. We also found that spontaneous polarization was achieved in starved cells by asymmetric localization of PTEN and F-actin. This breaking of the symmetry of protein localization maintained the leading edge and considerably enhanced the persistence of directed migration, and overall random exploration was ensured by switching among the different ordered patterns. Our findings suggest that Dictyostelium cells spontaneously create the ordered patterns of cell shape mediated by PI3K/PTEN/F-actin and control the direction of cell movement by coordination with these patterns even in the absence of external stimuli.
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Hussey, Peter S
2007-12-01
To analyze the dynamics of physician international migration patterns and identify the countries deviating most from expected migration rates. A negative binomial log-linear model of physician migration to the United States from every other country was constructed using a panel of country-level data for years 1994-2000. The model was used to identify factors associated with physician migration and to identify countries with higher or lower rates of physician migration than expected. Physician migration varied with a country's GDP per capita in an inverse-U pattern, with highest migration rates from middle-income countries. The absence of medical schools, immigrant networks in the United States, medical instruction in English, proximity to the United States, and the lack of political and civil liberties were also associated with higher migration rates. Countries with higher-than-predicted migration rates included Iceland, Albania, Armenia, Dominica, Lebanon, Syria, the United Arab Emirates, and Bulgaria. Countries with lower-than-predicted migration rates included Mexico, Japan, Brazil, Zimbabwe, Mauritania, Portugal, Senegal, and France. This analysis shows that many of the most powerful factors associated with physician migration are difficult or impossible for countries to change through public policy. GDP per capita and proximity to the U.S. are two of the most powerful predictors of physician migration. Networks of immigrants in the U.S. and fewer political and civil liberties also put countries at higher risk for physician emigration. Several other factors that were associated with physician migration might be more easily amenable to policy intervention. These factors include the absence of a medical school and medical instruction in English. Policies addressing these factors would involve making several difficult tradeoffs, however. Other examples of policies that are effective in minimizing physician migration might be found by examining countries with lower
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Birth Location, Migration and Clustering of Important Composers: Historical Patterns
DEFF Research Database (Denmark)
Borowiecki, Karol; O’Hagan, John
2010-01-01
and 1899. This information is compiled from the large, Grove Music Online (2009) encyclopedia. There is also some discussion of the biases evident in choosing “significant” composers. The data show a marked level ofmigration of important composers going back many centuries suggesting that the phenomenon......This article examines the 522 most important composers in the last 800 years, as identified by Charles Murray (2003), in terms of their birth location and migration. It also examines detailed patterns of migration and tendencies to cluster in certain cities for those composers born between 1750...
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Nelson, Abigail A; Kauffman, Matthew J; Middleton, Arthur D; Jimenez, Michael D; McWhirter, Douglas E; Barber, Jarrett; Gerow, Kenneth
2012-12-01
Identifying the ecological dynamics underlying human-wildlife conflicts is important for the management and conservation of wildlife populations. In landscapes still occupied by large carnivores, many ungulate prey species migrate seasonally, yet little empirical research has explored the relationship between carnivore distribution and ungulate migration strategy. In this study, we evaluate the influence of elk (Cervus elaphus) distribution and other landscape features on wolf (Canis lupus) habitat use in an area of chronic wolf-livestock conflict in the Greater Yellowstone Ecosystem, USA. Using three years of fine-scale wolf (n = 14) and elk (n = 81) movement data, we compared the seasonal habitat use of wolves in an area dominated by migratory elk with that of wolves in an adjacent area dominated by resident elk. Most migratory elk vacate the associated winter wolf territories each summer via a 40-60 km migration, whereas resident elk remain accessible to wolves year-round. We used a generalized linear model to compare the relative probability of wolf use as a function of GIS-based habitat covariates in the migratory and resident elk areas. Although wolves in both areas used elk-rich habitat all year, elk density in summer had a weaker influence on the habitat use of wolves in the migratory elk area than the resident elk area. Wolves employed a number of alternative strategies to cope with the departure of migratory elk. Wolves in the two areas also differed in their disposition toward roads. In winter, wolves in the migratory elk area used habitat close to roads, while wolves in the resident elk area avoided roads. In summer, wolves in the migratory elk area were indifferent to roads, while wolves in resident elk areas strongly avoided roads, presumably due to the location of dens and summering elk combined with different traffic levels. Study results can help wildlife managers to anticipate the movements and establishment of wolf packs as they expand into areas
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Cougoule, Céline; Lastrucci, Claire; Guiet, Romain; Mascarau, Rémi; Meunier, Etienne; Lugo-Villarino, Geanncarlo; Neyrolles, Olivier; Poincloux, Renaud; Maridonneau-Parini, Isabelle
2018-01-01
Dendritic cells (DC) are professional Antigen-Presenting Cells scattered throughout antigen-exposed tissues and draining lymph nodes, and survey the body for pathogens. Their ability to migrate through tissues, a 3D environment, is essential for an effective immune response. Upon infection, recognition of Pathogen-Associated Molecular Patterns (PAMP) by Toll-like receptors (TLR) triggers DC maturation. Mature DC (mDC) essentially use the protease-independent, ROCK-dependent amoeboid mode in vivo , or in collagen matrices in vitro . However, the mechanisms of 3D migration used by human immature DC (iDC) are still poorly characterized. Here, we reveal that human monocyte-derived DC are able to use two migration modes in 3D. In porous matrices of fibrillar collagen I, iDC adopted the amoeboid migration mode. In dense matrices of gelled collagen I or Matrigel, iDC used the protease-dependent, ROCK-independent mesenchymal migration mode. Upon TLR4 activation by LPS, mDC-LPS lose the capacity to form podosomes and degrade the matrix along with impaired mesenchymal migration. TLR2 activation by Pam 3 CSK 4 resulted in DC maturation, podosome maintenance, and efficient mesenchymal migration. Under all these conditions, when DC used the mesenchymal mode in dense matrices, they formed 3D podosomes at the tip of cell protrusions. Using PGE 2 , known to disrupt podosomes in DC, we observed that the cells remained in an immature status and the mesenchymal migration mode was abolished. We also observed that, while CCL5 (attractant of iDC) enhanced both amoeboid and mesenchymal migration of iDC, CCL19 and CCL21 (attractants of mDC) only enhanced mDC-LPS amoeboid migration without triggering mesenchymal migration. Finally, we examined the migration of iDC in tumor cell spheroids, a tissue-like 3D environment. We observed that iDC infiltrated spheroids of tumor cells using both migration modes. Altogether, these results demonstrate that human DC adopt the mesenchymal mode to
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Country-Specific Effects of Climate Variability on Human Migration
Gray, Clark; Wise, Erika
2016-01-01
Involuntary human migration is among the social outcomes of greatest concern in the current era of global climate change. Responding to this concern, a growing number of studies have investigated the consequences of short to medium-term climate variability for human migration using demographic and econometric approaches. These studies have provided important insights, but at the same time have been significantly limited by lack of expertise in the use of climate data, access to cross-national data on migration, and attention to model specification. To address these limitations, we link data on internal and international migration over a 6-year period from 9,812 origin households in Kenya, Uganda, Nigeria, Burkina Faso and Senegal to high-resolution gridded climate data from both station and satellite sources. Analyses of these data using several plausible specifications reveal that climate variability has country-specific effects on migration: Migration tends to increase with temperature anomalies in Uganda, tends to decrease with temperature anomalies in Kenya and Burkina Faso, and shows no consistent relationship with temperature in Nigeria and Senegal. Consistent with previous studies, precipitation shows weak and inconsistent relationships with migration across countries. These results challenge generalizing narratives that foresee a consistent migratory response to climate change across the globe. PMID:27092012
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Country-Specific Effects of Climate Variability on Human Migration.
Gray, Clark; Wise, Erika
2016-04-01
Involuntary human migration is among the social outcomes of greatest concern in the current era of global climate change. Responding to this concern, a growing number of studies have investigated the consequences of short to medium-term climate variability for human migration using demographic and econometric approaches. These studies have provided important insights, but at the same time have been significantly limited by lack of expertise in the use of climate data, access to cross-national data on migration, and attention to model specification. To address these limitations, we link data on internal and international migration over a 6-year period from 9,812 origin households in Kenya, Uganda, Nigeria, Burkina Faso and Senegal to high-resolution gridded climate data from both station and satellite sources. Analyses of these data using several plausible specifications reveal that climate variability has country-specific effects on migration: Migration tends to increase with temperature anomalies in Uganda, tends to decrease with temperature anomalies in Kenya and Burkina Faso, and shows no consistent relationship with temperature in Nigeria and Senegal. Consistent with previous studies, precipitation shows weak and inconsistent relationships with migration across countries. These results challenge generalizing narratives that foresee a consistent migratory response to climate change across the globe.
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Spatio-temporal dynamics of global H5N1 outbreaks match bird migration patterns
Directory of Open Access Journals (Sweden)
Yali Si
2009-11-01
Full Text Available The global spread of highly pathogenic avian influenza H5N1 in poultry, wild birds and humans, poses a significant pandemic threat and a serious public health risk. An efficient surveillance and disease control system relies on the understanding of the dispersion patterns and spreading mechanisms of the virus. A space-time cluster analysis of H5N1 outbreaks was used to identify spatio-temporal patterns at a global scale and over an extended period of time. Potential mechanisms explaining the spread of the H5N1 virus, and the role of wild birds, were analyzed. Between December 2003 and December 2006, three global epidemic phases of H5N1 influenza were identified. These H5N1 outbreaks showed a clear seasonal pattern, with a high density of outbreaks in winter and early spring (i.e., October to March. In phase I and II only the East Asia Australian flyway was affected. During phase III, the H5N1 viruses started to appear in four other flyways: the Central Asian flyway, the Black Sea Mediterranean flyway, the East Atlantic flyway and the East Africa West Asian flyway. Six disease cluster patterns along these flyways were found to be associated with the seasonal migration of wild birds. The spread of the H5N1 virus, as demonstrated by the space-time clusters, was associated with the patterns of migration of wild birds. Wild birds may therefore play an important role in the spread of H5N1 over long distances. Disease clusters were also detected at sites where wild birds are known to overwinter and at times when migratory birds were present. This leads to the suggestion that wild birds may also be involved in spreading the H5N1 virus over short distances.
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Bird migration patterns in the arid southwest-Final report
Ruth, Janet M.; Felix, Rodney K.; Dieh, Robert H.
2010-01-01
To ensure full life-cycle conservation, we need to understand migrant behavior en route and how migrating species use stopover and migration aerohabitats. In the Southwest, birds traverse arid and mountainous landscapes in migration. Migrants are known to use riparian stopover habitats; we know less about how migrant density varies across the Southwest seasonally and annually, and how migrants use other habitat types during migratory stopover. Furthermore, we lack information about migrant flight altitudes, speeds, and directions of travel, and how these patterns vary seasonally and annually across the Southwest. Using weather surveillance radar data, we identified targets likely dominated by nocturnally migrating birds and determined their flight altitudes, speeds, directions over ground, and variations in abundance. Migrating or foraging bats likely are present across the region in some of these data, particularly in central Texas. We found that migrants flew at significantly lower altitudes and significantly higher speeds in spring than in fall. In all seasons migrants maintained seasonally appropriate directions of movement. We detected significant differences in vertical structure of migrant densities that varied both geographically within seasons and seasonally within sites. We also found that in fall there was a greater and more variable passage of migrants through the central part of the borderlands (New Mexico and west Texas); in spring there was some suggestion of greater and more variable passage of migrants in the eastern borderlands (central and south Texas). Such patterns are consistent with the existence of at least two migration systems through western North America and the use of different migration routes in spring and fall for at least some species. Using radar data and satellite land cover data, we determined the habitats with which migrants are associated during migration stopover. There were significant differences in bird densities among
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Stroebele-Benschop, Nanette; Depa, Julia; Gyngell, Fiona; Müller, Annalena; Eleraky, Laila; Hilzendegen, Carolin
2018-03-29
People with low income tend to eat less balanced than people with higher income. This seems to be particularly the case for people with migration background. This cross-sectional study examined the relation of consumption patterns of 597 food bank users with different migration background in Germany. Questionnaires were distributed assessing sociodemographic information and consumption patterns. Analyses were conducted using binary logistic regressions. Models were controlled for age, gender, type of household and education. The group of German food bank users consumed fewer fruits and vegetables and less fish compared to all other groups with migration background (former USSR, Balkan region, Middle East). A significant predictor for fruit and vegetable consumption was migration status. Participants from the former USSR consumed less often SSBs compared to the other groups. Dietary recommendations for low income populations should take into consideration other aspects besides income such as migration status.
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Patterns of gravity induced aggregate migration during casting of fluid concretes
Energy Technology Data Exchange (ETDEWEB)
Spangenberg, J. [Department of Mechanical Engineering, Technical University of Denmark (DTU) (Denmark); Roussel, N., E-mail: Nicolas.roussel@lcpc.fr [Universite Paris Est, Laboratoire Central des Ponts et Chaussees (LCPC) (France); Hattel, J.H. [Department of Mechanical Engineering, Technical University of Denmark (DTU) (Denmark); Sarmiento, E.V.; Zirgulis, G. [Department of Structural Engineering, Norwegian University of Science and Technology (NTNU) (Norway); Geiker, M.R. [Department of Structural Engineering, Norwegian University of Science and Technology (NTNU) (Norway); Department of Civil Engineering, Technical University of Denmark (DTU) (Denmark)
2012-12-15
In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in a decrease of coarse aggregates volume fraction with the horizontal distance from the pouring point and in a puzzling vertical multi-layer structure. The origin of this multi layer structure is discussed and analyzed with the help of numerical simulations of free surface flow. Our results suggest that it finds its origin in the non Newtonian nature of fresh concrete and that increasing casting rate shall decrease the magnitude of gravity induced particle migration.
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Patterns of gravity induced aggregate migration during casting of fluid concretes
International Nuclear Information System (INIS)
Spangenberg, J.; Roussel, N.; Hattel, J.H.; Sarmiento, E.V.; Zirgulis, G.; Geiker, M.R.
2012-01-01
In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in a decrease of coarse aggregates volume fraction with the horizontal distance from the pouring point and in a puzzling vertical multi-layer structure. The origin of this multi layer structure is discussed and analyzed with the help of numerical simulations of free surface flow. Our results suggest that it finds its origin in the non Newtonian nature of fresh concrete and that increasing casting rate shall decrease the magnitude of gravity induced particle migration.
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New perspective on youth migration: Motives and family investment patterns
Directory of Open Access Journals (Sweden)
Jessica Heckert
2015-10-01
Full Text Available Background: Migration research commonly assumes that youth migrate as dependent family members or are motivated by current labor opportunities and immediate financial returns. These perspectives ignore how migration experiences, specifically motives and remittance behaviors, are unique to youth. Objective: This study investigates internal migration among the Haitian youth, aged 10-24. The study compares characteristics of youth who migrate with education and labor motives and determines characteristics associated with family financial support to youth migrants. Methods: The data are from the 2009 Haiti Youth Survey. Discrete-time event history analysis is used to model characteristics associated with education and labor migration. A two-stage Heckman probit model is used to determine characteristics associated with family financial support for two different samples of youth migrants. Results: Both education and labor migration become more common with increasing age. Education migration is more common among youth born outside the capital and those first enrolled in school on time. Labor migration differs little by region of birth, and is associated with late school enrollment. Moreover, rather than sending remittances home, many youth migrants continue to receive financial support from their parents. Provision of financial support to youth migrants is associated with current school enrollment. Female youth are more likely to be migrants, and less commonly receive support from their household of origin. Conclusions: Results illustrate that youth migration motives and remittance behaviors differ from those of adults, and many households of origin continue to invest in the human capital of youth migrants. Education migration may diversify household risk over an extended time horizon. Contribution: *
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Visualization of migration of human cortical neurons generated from induced pluripotent stem cells.
Bamba, Yohei; Kanemura, Yonehiro; Okano, Hideyuki; Yamasaki, Mami
2017-09-01
Neuronal migration is considered a key process in human brain development. However, direct observation of migrating human cortical neurons in the fetal brain is accompanied by ethical concerns and is a major obstacle in investigating human cortical neuronal migration. We established a novel system that enables direct visualization of migrating cortical neurons generated from human induced pluripotent stem cells (hiPSCs). We observed the migration of cortical neurons generated from hiPSCs derived from a control and from a patient with lissencephaly. Our system needs no viable brain tissue, which is usually used in slice culture. Migratory behavior of human cortical neuron can be observed more easily and more vividly by its fluorescence and glial scaffold than that by earlier methods. Our in vitro experimental system provides a new platform for investigating development of the human central nervous system and brain malformation. Copyright © 2017 Elsevier B.V. All rights reserved.
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Staby, A; Rø stad, Anders; Kaartvedt, Stein
2011-01-01
. The data revealed known patterns as normal diel vertical migration (DVM), midnight sinking between dusk and dawn, and periods without migrations, as well as novel behaviours consisting of early morning ascents, reverse diel vertical migrations
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Digital Repository Service at National Institute of Oceanography (India)
Vineetha, G.; Jyothibabu, R.; Madhu, N.V.; Kusum, K.K.; Sooria, P.M.; Shivaprasad, A.; Reny, P.D.; Deepak, M.P.
habitats is often determined by their dominant behavioral patterns: diel vertical migration (DVM) and tidal vertical migration (TVM). The modes of these endogenous rhythms often vary among estuaries based on the river runoff and tidal characteristics...
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HGF and c-Met Interaction Promotes Migration in Human Chondrosarcoma Cells
Tsou, Hsi-Kai; Chen, Hsien-Te; Hung, Ya-Huey; Chang, Chia-Hao; Li, Te-Mao; Fong, Yi-Chin; Tang, Chih-Hsin
2013-01-01
Chondrosarcoma is a type of highly malignant tumor with a potent capacity for local invasion and causing distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Hepatocyte growth factor (HGF) has been demonstrated to stimulate cancer proliferation, migration, and metastasis. However, the effect of HGF on migration activity of human chondrosarcoma cells is not well known. Here, we found that human chondrosarcoma tissues demonstrated significant expression of HGF, which was higher than that in normal cartilage. We also found that HGF increased the migration and expression of matrix metalloproteinase (MMP)-2 in human chondrosarcoma cells. c-Met inhibitor and siRNA reduced HGF-increased cell migration and MMP-2 expression. HGF treatment resulted in activation of the phosphatidylinositol 3′-kinase (PI3K)/Akt/PKCδ/NF-κB pathway, and HGF-induced expression of MMP-2 and cell migration was inhibited by specific inhibitors or siRNA-knockdown of PI3K, Akt, PKCδ, and NF-κB cascades. Taken together, our results indicated that HGF enhances migration of chondrosarcoma cells by increasing MMP-2 expression through the c-Met receptor/PI3K/Akt/PKCδ/NF-κB signal transduction pathway. PMID:23320110
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HGF and c-Met interaction promotes migration in human chondrosarcoma cells.
Directory of Open Access Journals (Sweden)
Hsi-Kai Tsou
Full Text Available Chondrosarcoma is a type of highly malignant tumor with a potent capacity for local invasion and causing distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Hepatocyte growth factor (HGF has been demonstrated to stimulate cancer proliferation, migration, and metastasis. However, the effect of HGF on migration activity of human chondrosarcoma cells is not well known. Here, we found that human chondrosarcoma tissues demonstrated significant expression of HGF, which was higher than that in normal cartilage. We also found that HGF increased the migration and expression of matrix metalloproteinase (MMP-2 in human chondrosarcoma cells. c-Met inhibitor and siRNA reduced HGF-increased cell migration and MMP-2 expression. HGF treatment resulted in activation of the phosphatidylinositol 3'-kinase (PI3K/Akt/PKCδ/NF-κB pathway, and HGF-induced expression of MMP-2 and cell migration was inhibited by specific inhibitors or siRNA-knockdown of PI3K, Akt, PKCδ, and NF-κB cascades. Taken together, our results indicated that HGF enhances migration of chondrosarcoma cells by increasing MMP-2 expression through the c-Met receptor/PI3K/Akt/PKCδ/NF-κB signal transduction pathway.
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Recent trends in human migrations: the case of the Venezuelan Andes.
Suarez, M M; Torrealba, R
1982-01-01
Changes in world capitalism caused prices of traditional raw materials to fall and new energy demands to arise at the end of the 19th and beginning of the 20th century. The Andean countries witnessed the fall in the value of their exports and began to receive large flows of foreign investment in mining and industry. Consequently, urban economies were strengthened and demographic patterns were changed. This led to the internal migrations and to a process of social change. These consequences are summarized from relevant studies focusing on Ecuador, Colombia, and Venezuela. Since the 1960s a compendium of information has become available which highlights the causes of the migration, migration patterns, the composition of migratory movements, and the mechanisms that the migrant uses to establish himself/herself in the city. Preston (1969) distinguished 2 migratory patterns in Ecuador: rural to urban, with migratory flows from the rural areas to urban centers and new industrial cities that experienced development and high demand for unskilled labor at comparatively high wages: and rural to rural, based on the movement of population from depressed rural areas to other areas in which programs for colonization or commercial agriculture have been promoted. In a study of Colombia, McGreevey (1968) identifies the lack of cultivatable land, rural violence in certain departments, and other economic and family causes as the principal factors that induced migrations to the cities. The study emphasizes that the predominant model of movement relates to "fill in" migration. The spatial mobility of the Venezuelan Andean population was initially outlined in a voluminous report on economic and social problems of the region (1954). The study indicates that during the intercensal period 1941-50 cities grew much more rapidly than rural "municipos" and that the drive to find employment and earn a living were the most important motives in the movement of peasants to the cities. All of the
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International migration and sustainable human development in eastern and southern Africa.
Oucho, J O
1995-01-01
International migration in eastern and southern Africa (ESA) is rarely addressed in population and development policies or regional organizations, and regional organizations must in the articulation of sustainable shared development identify the role of international migration. Poor quality data on international migration hampers analysis. Sustainable, shared, and human development within the region are subregional issues. Permanent migration is characterized among ESA countries as increasing demographic ethnic pluralism that may result in redrawing of territorial boundaries and further population movement. Portuguese and Arab settlement and integration in eastern areas resulted in coexistence, while European immigration to South Africa resulted in racial segregation. Modern colonial settlement and the aftermath of political conflict resulted in independent countries after the 1960s and outmigration of nonAfrican groups. Much of the labor migration in ESA is unskilled workers moving to South African mining regions. Labor migration to Zimbabwe and Zambia declined after the 1960s. The formation of the Common Market for ESA and the potential merger with the Preferential Trade Area and South African Development Community is a key approach to integration of migration into regional cooperation and shared development. Refugee movements create the most problems. Prior to 1992 ESA countries accounted for 83.4% of refugees, particularly in Mozambique, Ethiopia, and Somalia. Some countries blame poor economic performance on the deluge of refugees. Illegal migration is currently detected because of the required work permits, but the adoption of the Common Market would obscure this phenomenon. Human development is affected most by migrations related to drought, labor migration to strong economic areas, and return migration. The Inter-Governmental Authority on Drought and Development needs to become more active and establish better policies on nomadic and refugee movements and
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On the move: explaining migration patterns in Estonia during the transition period.
Tammaru, T; Sjoberg, O
1999-01-01
This paper attempts to explore the migration patterns during the transition period in Estonia. A structuration approach was used to analyze data from the Estonian Statistical Office collected in 1997. Findings show that for migration between urban and rural areas, work-related reasons have been the most important motivating factor in urban growth during the transition period. Also considered are the family and education. In relation to sociodemographic structure of the population, men cite work, while women count family-related reasons, as the main motive for migrating. As to nonregistration, the most significant reason relates to issues of ownership. Because migrants are living in rented housing, it is not possible for them to register even if they desire to do so. Other reasons include "temporary", associated with study and work; "juridical", bureaucratic matters; and "multiple places of residence". This analysis, however, is incomplete because the attitudes and patterns of behavior have only partially or perfunctorily been related to the dramatic changes that have occurred in Estonian society. Proper statistical data are needed to help examine trends at a more disaggregated spatial level.
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Inhibition of proliferation, migration and invasion of human non ...
African Journals Online (AJOL)
Purpose: To determine the effect of phlomisoside F (PMF) on the proliferation, migration and invasion of human non-small cell lung cancer cell line A549 and explore the possible mechanisms. Methods: The anti-proliferative effect of PMF on A549 cells was determined by CCK-8. Subsequently, migration and invasion were ...
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Directory of Open Access Journals (Sweden)
Vítor Jorge MB
2009-09-01
Full Text Available Abstract Background Helicobacter pylori colonizes the human stomach and is associated with gastritis, peptic ulcer, and gastric cancer. This ubiquitous association between H. pylori and humans is thought to be present since the origin of modern humans. The H. pylori genome encodes for an exceptional number of restriction and modifications (R-M systems. To evaluate if R-M systems are an adequate tool to determine the geographic distribution of H. pylori strains, we typed 221 strains from Africa, America, Asia, and Europe, and evaluated the expression of different 29 methyltransferases. Results Independence tests and logistic regression models revealed that ten R-M systems correlate with geographical localization. The distribution pattern of these methyltransferases may have been originated by co-divergence of regional H. pylori after its human host migrated out of Africa. The expression of specific methyltransferases in the H. pylori population may also reflect the genetic and cultural background of its human host. Methyltransferases common to all strains, M. HhaI and M. NaeI, are likely conserved in H. pylori, and may have been present in the bacteria genome since the human diaspora out of Africa. Conclusion This study indicates that some methyltransferases are useful geomarkers, which allow discrimination of bacterial populations, and that can be added to our tools to investigate human migrations.
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Environmental drivers of human migration in drylands - A spatial picture
Neumann, K.; Sietz, D.; Hilderink, H.; Janssen, P.; Kok, M.; Dijk, van H.
2015-01-01
It is widely accepted that environmental change can influence human migration. In particular, the environment plays a role in migration processes in drylands, in which environmental change—including increasing variability of rainfall, increasing frequency of droughts, chronic water shortage, and
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ERK-dependent and -independent pathways trigger human neural progenitor cell migration
International Nuclear Information System (INIS)
Moors, Michaela; Cline, Jason E.; Abel, Josef; Fritsche, Ellen
2007-01-01
Besides differentiation and apoptosis, cell migration is a basic process in brain development in which neural cells migrate several centimeters within the developing brain before reaching their proper positions and forming the right connections. For identifying signaling events that control neural migration and are therefore potential targets of chemicals to disturb normal brain development, we developed a human neurosphere-based migration assay based on normal human neural progenitor (NHNP) cells, in which the distance is measured that cells wander over time. Applying this assay, we investigated the role of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) in the regulation of NHNP cell migration. Exposure to model substances like ethanol or phorbol 12-myristate 13-acetate (PMA) revealed a correlation between ERK1/2 activation and cell migration. The participation of phospho-(P-) ERK1/2 was confirmed by exposure of the cells to the MEK inhibitor PD98059, which directly prohibits ERK1/2 phosphorylation and inhibited cell migration. We identified protein kinase C (PKC) and epidermal growth factor receptor (EGFR) as upstream signaling kinases governing ERK1/2 activation, thereby controlling NHNP cell migration. Additionally, treatments with src kinase inhibitors led to a diminished cell migration without affecting ERK1/2 phosphorylation. Based on these results, we postulate that migration of NHNP cells is controlled via ERK1/2-dependent and -independent pathways
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Astronomical Theory of Early Human Migration (Milutin Milankovic Medal Lecture)
Timmermann, Axel; Friedrich, Tobias
2017-04-01
archaeological evidence. The human dispersal model simulates multiple prominent migration waves of Homo sapiens across the Arabian Peninsula and the Levant region around 106-94, 89-73, 59-47 and 45-29 thousand years ago. These waves were caused by earth's axis wobble and its corresponding changes in climate seasonality and resulting large-scale shifts in vegetation in tropical/subtropical regions. Such shifts opened up green corridors between Africa, the Sinai and the Arabian Peninsula, enabling Homo sapiens to leave Northeastern Africa and migrate into Asia, Europe, Australia and eventually into the Americas. The model also simulates a complex pattern of human dispersal out of Africa and back flow into Africa, that challenges the more unidirectional away-from-Africa perspective that is still very prevalent in anthropology and some genetic studies. Paleo-genetic reconstructions indicate that the first exodus out of Africa must have occurred around 70-60 thousand years ago. In contrast, our computer simulations and paleo-climate data show that northeastern Africa experienced one of its most severe long-term droughts during this time. The resulting large desert areas would have been an impenetrable natural border for early human migration. More research needs to be done to help reconcile and synthesize genetic, archaeological, climatological and anthropological data.
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Teitelbaum, Claire S; Converse, Sarah J; Fagan, William F; Böhning-Gaese, Katrin; O'Hara, Robert B; Lacy, Anne E; Mueller, Thomas
2016-09-06
Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Spatial changes in migration have been related to long-term temperature trends, but the intrinsic mechanisms by which migratory species adapt to environmental change remain largely unexplored. We show that, for a long-lived social species, older birds with more experience are critical for innovating new migration behaviours. Groups containing older, more experienced individuals establish new overwintering sites closer to the breeding grounds, leading to a rapid population-level shift in migration patterns. Furthermore, these new overwintering sites are in areas where changes in climate have increased temperatures and where food availability from agriculture is high, creating favourable conditions for overwintering. Our results reveal that the age structure of populations is critical for the behavioural mechanisms that allow species to adapt to global change, particularly for long-lived animals, where changes in behaviour can occur faster than evolution.
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Teitelbaum, Claire S.; Converse, Sarah J.; Fagan, William F.; Böhning-Gaese, Katrin; O'Hara, Robert B.; Lacy, Anne E; Mueller, Thomas
2016-01-01
Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Spatial changes in migration have been related to long-term temperature trends, but the intrinsic mechanisms by which migratory species adapt to environmental change remain largely unexplored. We show that, for a long-lived social species, older birds with more experience are critical for innovating new migration behaviours. Groups containing older, more experienced individuals establish new overwintering sites closer to the breeding grounds, leading to a rapid population-level shift in migration patterns. Furthermore, these new overwintering sites are in areas where changes in climate have increased temperatures and where food availability from agriculture is high, creating favourable conditions for overwintering. Our results reveal that the age structure of populations is critical for the behavioural mechanisms that allow species to adapt to global change, particularly for long-lived animals, where changes in behaviour can occur faster than evolution.
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Vineetha, G.
2015-04-03
Monsoonal estuaries, located along the coastline of the Indian subcontinent, differ from other estuaries by their time dependence on the salinity characteristics. Effective sustenance and retention of the mesozooplankton community in the estuarine habitats is often determined by their dominant behavioral patterns: diel vertical migration (DVM) and tidal vertical migration (TVM). The modes of these endogenous rhythms often vary among estuaries based on the river runoff and tidal characteristics. The present study is a pioneering attempt to depict the vertical migration pattern of zooplankton along a diel and tidal scale in a tropical, microtidal, monsoonal estuary. We observed that in spite of the prominent asymmetry in the magnitude of the river runoff between the seasons, most of the zooplankton groups exhibited strong DVM, with a clear increase in biomass and abundance in surface waters during night. The peak increase in biomass and abundance at night always synchronized with the slack periods in the tidal cycles, which differed from the general concepts of downward migration during ebb tide and upward migration during flood tide in estuarine systems. The weak currents during the slack period might have favored the effective vertical migration of the mesozooplankton community in this monsoonal estuarine system. © 2015 Society of Wetland Scientists
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Migration and chemokine receptor pattern of colitis-preventing DX5+NKT cells.
Hornung, Matthias; Werner, Jens M; Farkas, Stefan; Schlitt, Hans J; Geissler, Edward K
2011-11-01
DX5(+)NKT cells are a subpopulation of NKT cells expressing both T cell receptor and NK cell markers that show an immune-regulating function. Transferred DX5(+)NKT cells from immune competent Balb/c mice can prevent or reduce induced colitis in severe combined immunodeficient (SCID) mice. Here, we investigated the in vivo migration of DX5(+)NKT cells and their corresponding chemokine receptor patterns. DX5(+)NKT cells were isolated from spleens of Balb/c mice and transferred into Balb/c SCID mice. After 2 and 8 days, in vivo migration was examined using in vivo microscopy. In addition, the chemokine receptor pattern was analyzed with fluorescence-activated cell sorting (FACS) and the migration assay was performed. Our results show that labeled DX5(+)NKT cells were primarily detectable in mesenteric lymph nodes and spleen after transfer. After 8 days, DX5(+)NKT cells were observed in the colonic tissues, especially the appendix. FACS analysis of chemokine receptors in DX5(+)NKT cells revealed expression of CCR3, CCR6, CCR9, CXCR3, CXCR4, and CXCR6, but no CCR5, CXCR5, or the lymphoid homing receptor CCR7. Stimulation upregulated especially CCR7 expression, and chemokine receptor patterns were different between splenic and liver DX5(+)NKT cells. These data indicate that colitis-preventing DX5(+)NKT cells need to traffic through lymphoid organs to execute their immunological function at the site of inflammation. Furthermore, DX5(+)NKT cells express a specific chemokine receptor pattern with an upregulation of the lymphoid homing receptor CCR7 after activation.
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Guerrero-Cazares, Hugo; Lavell, Emily; Chen, Linda; Schiapparelli, Paula; Lara-Velazquez, Montserrat; Capilla-Gonzalez, Vivian; Clements, Anna Christina; Drummond, Gabrielle; Noiman, Liron; Thaler, Katrina; Burke, Anne; Quiñones-Hinojosa, Alfredo
2017-07-01
Human neural progenitor cell (NPC) migration within the subventricular zone (SVZ) of the lateral ganglionic eminence is an active process throughout early brain development. The migration of human NPCs from the SVZ to the olfactory bulb during fetal stages resembles what occurs in adult rodents. As the human brain develops during infancy, this migratory stream is drastically reduced in cell number and becomes barely evident in adults. The mechanisms regulating human NPC migration are unknown. The Slit-Robo signaling pathway has been defined as a chemorepulsive cue involved in axon guidance and neuroblast migration in rodents. Slit and Robo proteins expressed in the rodent brain help guide neuroblast migration from the SVZ through the rostral migratory stream to the olfactory bulb. Here, we present the first study on the role that Slit and Robo proteins play in human-derived fetal neural progenitor cell migration (hfNPC). We describe that Robo1 and Robo2 isoforms are expressed in the human fetal SVZ. Furthermore, we demonstrate that Slit2 is able to induce a chemorepellent effect on the migration of hfNPCs derived from the human fetal SVZ. In addition, when Robo1 expression is inhibited, hfNPCs are unable to migrate to the olfactory bulb of mice when injected in the anterior SVZ. Our findings indicate that the migration of human NPCs from the SVZ is partially regulated by the Slit-Robo axis. This pathway could be regulated to direct the migration of NPCs in human endogenous neural cell therapy. Stem Cells 2017;35:1860-1865. © 2017 AlphaMed Press.
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Long-Distance Dispersal Shaped Patterns of Human Genetic Diversity in Eurasia.
Alves, Isabel; Arenas, Miguel; Currat, Mathias; Sramkova Hanulova, Anna; Sousa, Vitor C; Ray, Nicolas; Excoffier, Laurent
2016-04-01
Most previous attempts at reconstructing the past history of human populations did not explicitly take geography into account or considered very simple scenarios of migration and ignored environmental information. However, it is likely that the last glacial maximum (LGM) affected the demography and the range of many species, including our own. Moreover, long-distance dispersal (LDD) may have been an important component of human migrations, allowing fast colonization of new territories and preserving high levels of genetic diversity. Here, we use a high-quality microsatellite data set genotyped in 22 populations to estimate the posterior probabilities of several scenarios for the settlement of the Old World by modern humans. We considered models ranging from a simple spatial expansion to others including LDD and a LGM-induced range contraction, as well as Neolithic demographic expansions. We find that scenarios with LDD are much better supported by data than models without LDD. Nevertheless, we show evidence that LDD events to empty habitats were strongly prevented during the settlement of Eurasia. This unexpected absence of LDD ahead of the colonization wave front could have been caused by an Allee effect, either due to intrinsic causes such as an inbreeding depression built during the expansion or due to extrinsic causes such as direct competition with archaic humans. Overall, our results suggest only a relatively limited effect of the LGM contraction on current patterns of human diversity. This is in clear contrast with the major role of LDD migrations, which have potentially contributed to the intermingled genetic structure of Eurasian populations. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
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Directory of Open Access Journals (Sweden)
Baltica Cabieses
Full Text Available Migration patterns in Latin America have changed significantly in recent decades, particularly since the onset of global recession in 2007. These recent economic changes have highlighted and exacerbated the weakness of evidence from Latin America regarding migration-a crucial determinant of health. Migration patterns are constantly evolving in Latin America, but research on migration has not developed at the same speed. This article focuses on the need for better understanding of the living conditions and health of migrant populations in Latin America within the context of the recent global recession. The authors explain how new data on migrant well-being could be obtained through improved evidence from censuses and ongoing research surveys to 1 better inform policy-makers about the needs of migrant populations in Latin America and 2 help determine better ways of reaching undocumented immigrants. Longitudinal studies on immigrants in Latin America are essential for generating a better representation of migrant living conditions and health needs during the initial stages of immigration and over time. To help meet this need, the authors support the promotion of sustainable sources of data and evidence on the complex relationship between migration and health.
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Russian, Soviet, and post-Soviet scientific migration: history and patterns
Kojevnikov, Alexei
2011-03-01
Immigrant scientists from other European countries (predominantly German) were crucial in establishing the tradition of modern science in the Russian Empire of the 18th and 19th centuries. Since the 1860s, however, outgoing waves of scientific migration started originating in Russia, bringing important innovations to international science. The scale and patterns of migration varied greatly with the turbulent time. The talk will describe several landmark stages of the proceess and their cultural consequences: from opening higher education possibilities for women during the late 19th century, to post-1917 academic refugees and Soviet defectors, to the 1960s brain drain provoked by the launch of Sputnik, and to what can be called the first truly global scientific diaspora of Russophone scientists after 1990.
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Breurec, Sebastien; Guillard, Bertrand; Hem, Sopheak; Brisse, Sylvain; Dieye, Fatou Bintou; Huerre, Michel; Oung, Chakravuth; Raymond, Josette; Tan, Tek Sreng; Thiberge, Jean-Michel; Vong, Sirenda; Monchy, Didier; Linz, Bodo
2011-01-01
The human population history in Southeast Asia was shaped by numerous migrations and population expansions. Their reconstruction based on archaeological, linguistic or human genetic data is often hampered by the limited number of informative polymorphisms in classical human genetic markers, such as the hypervariable regions of the mitochondrial DNA. Here, we analyse housekeeping gene sequences of the human stomach bacterium Helicobacter pylori from various countries in Southeast Asia and we provide evidence that H. pylori accompanied at least three ancient human migrations into this area: i) a migration from India introducing hpEurope bacteria into Thailand, Cambodia and Malaysia; ii) a migration of the ancestors of Austro-Asiatic speaking people into Vietnam and Cambodia carrying hspEAsia bacteria; and iii) a migration of the ancestors of the Thai people from Southern China into Thailand carrying H. pylori of population hpAsia2. Moreover, the H. pylori sequences reflect iv) the migrations of Chinese to Thailand and Malaysia within the last 200 years spreading hspEasia strains, and v) migrations of Indians to Malaysia within the last 200 years distributing both hpAsia2 and hpEurope bacteria. The distribution of the bacterial populations seems to strongly influence the incidence of gastric cancer as countries with predominantly hspEAsia isolates exhibit a high incidence of gastric cancer while the incidence is low in countries with a high proportion of hpAsia2 or hpEurope strains. In the future, the host range expansion of hpEurope strains among Asian populations, combined with human motility, may have a significant impact on gastric cancer incidence in Asia.
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Stark, Oded
2007-01-01
At least to some extent migration behavior is the outcome of a preference for migration. The pattern of migration as an outcome of a preference for migration depends on two key factors: imitation technology and migration feasibility. We show that these factors jointly determine the outcome of a preference for migration and we provide examples that illustrate how the prevalence and transmission of a migration-forming preference yield distinct migration patterns. In particular, the imitation of...
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Manhard, Christopher V.; Som, Nicholas A.; Perry, Russell W.; Faukner, Jimmy; Soto, Toz
2018-01-01
An area of great importance to resource management and conservation biology in the Klamath Basin is balancing water usage against the life history requirements of threatened Coho Salmon. One tool for addressing this topic is a freshwater dynamics model to forecast Coho Salmon productivity based on environmental inputs. Constructing such a forecasting tool requires local data to quantify the unique life history processes of Coho Salmon inhabiting this region. Here, we describe analytical methods for estimating a series of sub-models, each capturing a different life history process, which will eventually be synchronized as part of a freshwater dynamics model for Klamath River Coho Salmon. Specifically, we draw upon extensive population monitoring data collected in the basin to estimate models of freshwater productivity, overwinter survival, and migration patterns. Our models of freshwater productivity indicated that high summer temperatures and high winter flows can both adversely affect smolt production and that such relationships are more likely in tributaries with naturally regulated flows due to substantial intraannual environmental variation. Our models of overwinter survival demonstrated extensive variability in survival among years, but not among rearing locations, and demonstrated that a substantial proportion (~ 20%) of age-0+ fish emigrate from some rearing sites in the winter. Our models of migration patterns indicated that many age-0+ fish redistribute in the basin during the summer and winter. Further, we observed that these redistributions can entail long migrations in the mainstem where environmental stressors likely play a role in cueing refuge entry. Finally, our models of migration patterns indicated that changes in discharge are important in cueing the seaward migration of smolts, but that the nature of this behavioral response can differ dramatically between tributaries with naturally and artificially regulated flows. Collectively, these analyses
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Demographic and human dimension of international migration in Ukraine
Duhinets H. V.; Rielina I. Ie.
2015-01-01
Modern transformation of the economic system of this country led to structural changes in the social environment. Movement of population and human resources inside and outside the country increased. The growth of the scale of international migration processes, their mixed impact on the development of the countries, qualitative transformation of the specified processes determine the importance of the study of demographic and employment dimension of the international migration processes in Ukra...
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Out of Africa: the importance of rivers as human migration corridors
Ramirez, J. A.; Coulthard, T. J.; Rogerson, M.; Barton, N.; Bruecher, T.
2013-12-01
The route and timing of Homo sapiens exiting Africa remains uncertain. Corridors leading out of Africa through the Sahara, the Nile Valley, and the Red Sea coast have been proposed as migration routes for anatomically modern humans 80,000-130,000 years ago. During this time climate conditions in the Sahara were wetter than present day, and monsoon rainfall fed rivers that flowed across the desert landscape. The location and timing of these rivers may have supported human migration northward from central Africa to the Mediterranean coast, and onwards to Europe or Asia. Here, we use palaeoclimate rainfall and a hydrological model to spatially simulate and quantitatively test the existence of three major rivers crossing the Sahara from south to north during the time of human migration. We provide evidence that, given realistic underlying climatology, the well-known Sahabi and Kufrah rivers very likely flowed across modern day Libya and reached the coast. More unexpectedly an additional river crossed the core of the Sahara through Algeria (Irharhar river) and flowed into the Chotts basin. The Irharhar river is unique, because it links locations in central Africa experiencing monsoon climates with temperate coastal Mediterranean environments where food and resources were likely abundant. From an ecological perspective, this little-known corridor may prove to be the most parsimonious migration route. Support for the Irharar as a viable migration corridor is provided by its geographic proximity to middle Stone Age archaeological artefacts found in North Africa. Our new, highly novel approach provides the first quantitative analysis of the likelihood that rivers occurred during the critical period of human migration out of Africa. Simulated probability of surface water in North Africa during the last interglacial and the location of tools and ornaments from the Middle Stone Age.
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Daly, Ryan; Smale, Malcolm J.; Cowley, Paul D.; Froneman, Pierre W.
2014-01-01
Bull sharks (Carcharhinus leucas) are globally distributed top predators that play an important ecological role within coastal marine communities. However, little is known about the spatial and temporal scales of their habitat use and associated ecological role. In this study, we employed passive acoustic telemetry to investigate the residency patterns and migration dynamics of 18 adult bull sharks (195–283 cm total length) tagged in southern Mozambique for a period of between 10 and 22 months. The majority of sharks (n = 16) exhibited temporally and spatially variable residency patterns interspersed with migration events. Ten individuals undertook coastal migrations that ranged between 433 and 709 km (mean = 533 km) with eight of these sharks returning to the study site. During migration, individuals exhibited rates of movement between 2 and 59 km.d−1 (mean = 17.58 km.d−1) and were recorded travelling annual distances of between 450 and 3760 km (mean = 1163 km). Migration towards lower latitudes primarily took place in austral spring and winter and there was a significant negative correlation between residency and mean monthly sea temperature at the study site. This suggested that seasonal change is the primary driver behind migration events but further investigation is required to assess how foraging and reproductive activity may influence residency patterns and migration. Results from this study highlight the need for further understanding of bull shark migration dynamics and suggest that effective conservation strategies for this vulnerable species necessitate the incorporation of congruent trans-boundary policies over large spatial scales. PMID:25295972
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Nelson, Abigail; Kauffman, Matthew J.; Middleton, Arthur D.; Jimenez, Mike; McWhirter, Douglas; Barber, Jarrett; Gerow, Ken
2012-01-01
Identifying the ecological dynamics underlying human–wildlife conflicts is important for the management and conservation of wildlife populations. In landscapes still occupied by large carnivores, many ungulate prey species migrate seasonally, yet little empirical research has explored the relationship between carnivore distribution and ungulate migration strategy. In this study, we evaluate the influence of elk (Cervus elaphus) distribution and other landscape features on wolf (Canis lupus) habitat use in an area of chronic wolf–livestock conflict in the Greater Yellowstone Ecosystem, USA. Using three years of fine-scale wolf (n = 14) and elk (n = 81) movement data, we compared the seasonal habitat use of wolves in an area dominated by migratory elk with that of wolves in an adjacent area dominated by resident elk. Most migratory elk vacate the associated winter wolf territories each summer via a 40–60 km migration, whereas resident elk remain accessible to wolves year-round. We used a generalized linear model to compare the relative probability of wolf use as a function of GIS-based habitat covariates in the migratory and resident elk areas. Although wolves in both areas used elk-rich habitat all year, elk density in summer had a weaker influence on the habitat use of wolves in the migratory elk area than the resident elk area. Wolves employed a number of alternative strategies to cope with the departure of migratory elk. Wolves in the two areas also differed in their disposition toward roads. In winter, wolves in the migratory elk area used habitat close to roads, while wolves in the resident elk area avoided roads. In summer, wolves in the migratory elk area were indifferent to roads, while wolves in resident elk areas strongly avoided roads, presumably due to the location of dens and summering elk combined with different traffic levels. Study results can help wildlife managers to anticipate the movements and establishment of wolf packs as they expand into
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The modelling of 2-D migration patterns of soluble waste in soils
International Nuclear Information System (INIS)
Villar, H.P.
1998-01-01
A novel approach to the modelling of two-dimensional migration patterns of soluble waste in soils is presented. This approach, albeit very simple and straightforward, was found to be powerful enough to simulate several aspects of the migration of conservative tracers in non-sorptive soils. In brief, the finite-difference technique is adopted for the solution of the two-dimensional advection-dispersion equation. Since the simulated data were to be verified against experimental data obtained through the use of radioactive tracers, the numerical model was modified to take into account the corresponding experimental aspects, with special regard to the attenuation of radiation through the soil mass. The introduction of this correcting factor rendered the simulation quite faithful to the experimental data, thus suggesting the feasibility of the proposed approach for the two-dimensional analysis of waste migration. (author)
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Matchmaker, Matchmaker, Make Me a Match: Migration of Populations via Marriages in the Past
Directory of Open Access Journals (Sweden)
Sang Hoon Lee (이상훈
2014-10-01
Full Text Available The study of human mobility is both of fundamental importance and of great potential value. For example, it can be leveraged to facilitate efficient city planning and improve prevention strategies when faced with epidemics. The newfound wealth of rich sources of data—including banknote flows, mobile phone records, and transportation data—has led to an explosion of attempts to characterize modern human mobility. Unfortunately, the dearth of comparable historical data makes it much more difficult to study human mobility patterns from the past. In this paper, we present an analysis of long-term human migration, which is important for processes such as urbanization and the spread of ideas. We demonstrate that the data record from Korean family books (called “jokbo” can be used to estimate migration patterns via marriages from the past 750 years. We apply two generative models of long-term human mobility to quantify the relevance of geographical information to human marriage records in the data, and we find that the wide variety in the geographical distributions of the clans poses interesting challenges for the direct application of these models. Using the different geographical distributions of clans, we quantify the “ergodicity” of clans in terms of how widely and uniformly they have spread across Korea, and we compare these results to those obtained using surname data from the Czech Republic. To examine population flow in more detail, we also construct and examine a population-flow network between regions. Based on the correlation between ergodicity and migration in Korea, we identify two different types of migration patterns: diffusive and convective. We expect the analysis of diffusive versus convective effects in population flows to be widely applicable to the study of mobility and migration patterns across different cultures.
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Matchmaker, Matchmaker, Make Me a Match: Migration of Populations via Marriages in the Past
Lee, Sang Hoon; Ffrancon, Robyn; Abrams, Daniel M.; Kim, Beom Jun; Porter, Mason A.
2014-10-01
The study of human mobility is both of fundamental importance and of great potential value. For example, it can be leveraged to facilitate efficient city planning and improve prevention strategies when faced with epidemics. The newfound wealth of rich sources of data—including banknote flows, mobile phone records, and transportation data—has led to an explosion of attempts to characterize modern human mobility. Unfortunately, the dearth of comparable historical data makes it much more difficult to study human mobility patterns from the past. In this paper, we present an analysis of long-term human migration, which is important for processes such as urbanization and the spread of ideas. We demonstrate that the data record from Korean family books (called "jokbo") can be used to estimate migration patterns via marriages from the past 750 years. We apply two generative models of long-term human mobility to quantify the relevance of geographical information to human marriage records in the data, and we find that the wide variety in the geographical distributions of the clans poses interesting challenges for the direct application of these models. Using the different geographical distributions of clans, we quantify the "ergodicity" of clans in terms of how widely and uniformly they have spread across Korea, and we compare these results to those obtained using surname data from the Czech Republic. To examine population flow in more detail, we also construct and examine a population-flow network between regions. Based on the correlation between ergodicity and migration in Korea, we identify two different types of migration patterns: diffusive and convective. We expect the analysis of diffusive versus convective effects in population flows to be widely applicable to the study of mobility and migration patterns across different cultures.
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Human Resources for Health Challenges in Nigeria and Nurse Migration.
Salami, Bukola; Dada, Foluke O; Adelakun, Folake E
2016-05-01
The emigration of sub-Saharan African health professionals to developed Western nations is an aspect of increasing global mobility. This article focuses on the human resources for health challenges in Nigeria and the emigration of nurses from Nigeria as the country faces mounting human resources for health challenges. Human resources for health issues in Nigeria contribute to poor population health in the country, alongside threats from terrorism, infectious disease outbreaks, and political corruption. Health inequities within Nigeria mirror the geographical disparities in human resources for health distribution and are worsened by the emigration of Nigerian nurses to developed countries such as the United States and the United Kingdom. Nigerian nurses are motivated to emigrate to work in healthier work environments, improve their economic prospects, and advance their careers. Like other migrant African nurses, they experience barriers to integration, including racism and discrimination, in receiving countries. We explore the factors and processes that shape this migration. Given the forces of globalization, source countries and destination countries must implement policies to more responsibly manage migration of nurses. This can be done by implementing measures to retain nurses, promote the return migration of expatriate nurses, and ensure the integration of migrant nurses upon arrival in destination countries. © The Author(s) 2016.
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Minocycline affects human neutrophil respiratory burst and transendothelial migration.
Parenti, Astrid; Indorato, Boris; Paccosi, Sara
2017-02-01
This study aimed at investigating the in vitro activity of minocycline and doxycycline on human polymorphonuclear (h-PMN) cell function. h-PMNs were isolated from whole venous blood of healthy subjects; PMN oxidative burst was measured by monitoring ROS-induced oxidation of luminol and transendothelial migration was studied by measuring PMN migration through a monolayer of human umbilical vein endothelial cells. Differences between multiple groups were determined by ANOVA followed by Tukey's multiple comparison test; Student's t test for unpaired data for two groups. Minocycline (1-300 µM) concentration dependently and significantly inhibited oxidative burst of h-PMNs stimulated with 100 nM fMLP. Ten micromolar concentrations, which are superimposable to C max following a standard oral dose of minocycline, promoted a 29.8 ± 4 % inhibition of respiratory burst (P minocycline impaired PMN transendothelial migration, with maximal effect at 100 µM (42.5 ± 7 %, inhibition, n = 5, P minocycline exerted on innate immune h-PMN cell function.
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Endogenous cannabinoid receptor ligand induces the migration of human natural killer cells.
Kishimoto, Seishi; Muramatsu, Mayumi; Gokoh, Maiko; Oka, Saori; Waku, Keizo; Sugiura, Takayuki
2005-02-01
2-Arachidonoylglycerol is an endogenous ligand for the cannabinoid receptors (CB1 and CB2). Evidence is gradually accumulating which shows that 2-arachidonoylglycerol plays important physiological roles in several mammalian tissues and cells, yet the details remain ambiguous. In this study, we first examined the effects of 2-arachidonoylglycerol on the motility of human natural killer cells. We found that 2-arachidonoylglycerol induces the migration of KHYG-1 cells (a natural killer leukemia cell line) and human peripheral blood natural killer cells. The migration of natural killer cells induced by 2-arachidonoylglycerol was abolished by treating the cells with SR144528, a CB2 receptor antagonist, suggesting that the CB2 receptor is involved in the 2-arachidonoylglycerol-induced migration. In contrast to 2-arachidonoylglycerol, anandamide, another endogenous cannabinoid receptor ligand, did not induce the migration. Delta9-tetrahydrocannabinol, a major psychoactive constituent of marijuana, also failed to induce the migration; instead, the addition of delta9-tetrahydrocannabinol together with 2-arachidonoylglycerol abolished the migration induced by 2-arachidonoylglycerol. It is conceivable that the endogenous ligand for the cannabinoid receptor, that is, 2-arachidonoylglycerol, affects natural killer cell functions such as migration, thereby contributing to the host-defense mechanism against infectious viruses and tumor cells.
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Laser-photophoretic migration and fractionation of human blood cells
International Nuclear Information System (INIS)
Monjushiro, Hideaki; Tanahashi, Yuko; Watarai, Hitoshi
2013-01-01
Graphical abstract: -- Highlights: •RBCs were migrated faster than WBCs and blood pellets by laser photophoresis. •Photophoretic efficiency of RBC and WBC was simulated by the Mie scattering theory. •Spontaneous orientation of RBC parallel to the migration direction was elucidated. •Laser photophoretic separation of RBC and WBC was possible in a tip flow system. -- Abstract: Laser photophoretic migration behavior of human blood cells in saline solution was investigated under the irradiation of Nd:YAG laser beam (532 nm) in the absence and the presence of the flow in a fused silica capillary. Red blood cells (RBC) were migrated faster than white blood cells (WBC) and blood pellets to the direction of propagation of laser light. The observed photophoretic velocity of RBC was about 11 times faster than those of others. This was understood from the larger photophoretic efficiency of RBC than that of WBC, which was simulated based on the Mie scattering theory. Furthermore, it was found that, during the photophoretic migration, RBCs spontaneously orientated parallel to the migration direction so as to reduce the drag force. Finally, it was demonstrated that RBC and WBC were separated in a micro-channel flow system by the laser photophoresis
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Laser-photophoretic migration and fractionation of human blood cells
Energy Technology Data Exchange (ETDEWEB)
Monjushiro, Hideaki; Tanahashi, Yuko; Watarai, Hitoshi, E-mail: watarai@chem.sci.osaka-u.ac.jp
2013-05-13
Graphical abstract: -- Highlights: •RBCs were migrated faster than WBCs and blood pellets by laser photophoresis. •Photophoretic efficiency of RBC and WBC was simulated by the Mie scattering theory. •Spontaneous orientation of RBC parallel to the migration direction was elucidated. •Laser photophoretic separation of RBC and WBC was possible in a tip flow system. -- Abstract: Laser photophoretic migration behavior of human blood cells in saline solution was investigated under the irradiation of Nd:YAG laser beam (532 nm) in the absence and the presence of the flow in a fused silica capillary. Red blood cells (RBC) were migrated faster than white blood cells (WBC) and blood pellets to the direction of propagation of laser light. The observed photophoretic velocity of RBC was about 11 times faster than those of others. This was understood from the larger photophoretic efficiency of RBC than that of WBC, which was simulated based on the Mie scattering theory. Furthermore, it was found that, during the photophoretic migration, RBCs spontaneously orientated parallel to the migration direction so as to reduce the drag force. Finally, it was demonstrated that RBC and WBC were separated in a micro-channel flow system by the laser photophoresis.
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Directory of Open Access Journals (Sweden)
Tom J Coulthard
Full Text Available Human migration north through Africa is contentious. This paper uses a novel palaeohydrological and hydraulic modelling approach to test the hypothesis that under wetter climates c.100,000 years ago major river systems ran north across the Sahara to the Mediterranean, creating viable migration routes. We confirm that three of these now buried palaeo river systems could have been active at the key time of human migration across the Sahara. Unexpectedly, it is the most western of these three rivers, the Irharhar river, that represents the most likely route for human migration. The Irharhar river flows directly south to north, uniquely linking the mountain areas experiencing monsoon climates at these times to temperate Mediterranean environments where food and resources would have been abundant. The findings have major implications for our understanding of how humans migrated north through Africa, for the first time providing a quantitative perspective on the probabilities that these routes were viable for human habitation at these times.
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Illegal Migration and Human Smuggling in Central and Eastern Europe
Directory of Open Access Journals (Sweden)
Peter Futo
2005-06-01
Full Text Available The analytical and statistical services of border management organizations in Central and Eastern European countries have registered and accumulated a vast body of knowledge on the demographics and mechanisms of illegal migration over the last one-and-a-half decade. This paper attempts to tap this resource by summarising the results of a yearly survey among border guards of 17 countries. A set of quantitative indicators of illegal migration is developed, presented and interpreted, based on the answers of the border services to a series of quantitative and qualitative questions. This empirical material is used to evaluate the dynamics and pattern of illegal migration in Central and Eastern Europe on the one hand, and to examine the development of border management strategies on the other. The impacts of legal and institutional reforms are investigated in light of the temporal and spatial variations of border apprehension statistics. The interdependence of the two processes is reviewed from the point of view of national border management authorities, perhaps the most authoritative source of information on the issue. The results of the authors’ annual survey indicate that the progressive development of migration control mechanisms at national and international levels seems to have a significant impact on irregular migration flows as most indicators of illegal migration have significantly decreased after the turn of the century. At the same time, the geographical distribution of illegal migration flows in Central and Eastern European countries has become more complex over the years.
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Population migration and the spread of types 1 and 2 human immunodeficiency viruses.
Quinn, T C
1994-03-29
Over 14 million people are estimated to be infected with the human immunodeficiency viruses (HIV), with nearly three-fourths of the infected persons residing in developing countries. One factor responsible for dissemination of both HIV-1 and HIV-2 worldwide was the intense migration of individuals, from rural to urban centers with subsequent return migration and internationally due to civil wars, tourism, business purposes, and the drug trade. In sub-Saharan Africa, between 1960 and 1980, urban centers with more than 500,000 inhabitants increased from 3 to 28, and more than 75 military coups occurred in 30 countries. The result was a massive migration of rural inhabitants to urban centers concomitant with the spread of HIV-1 to large population centers. With the associated demographic, economic, and social changes, an epidemic of sexually transmitted diseases and HIV-1 was ignited. Migratory patterns were also responsible for the spread of endemic HIV-2 to neighboring West African countries and eventually to Europe, the Americans, and India. Although Southeast Asia was the last region in which HIV-1 was introduced, it has the greatest potential for rapid spread due to population density and inherent risk behaviors. Thus, the migration of poor, rural, and young sexually active individuals to urban centers coupled with large international movements of HIV-infected individuals played a prominent role in the dissemination of HIV globally. The economic recession has aggravated the transmission of HIV by directly increasing the population at risk through increased urban migration, disruption of rural families and cultural values, poverty, and prostitution and indirectly through a decrease in health care provision. Consequently, social and economic reform as well as sexual behavior education need to be intensified if HIV transmission is to be controlled.
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Human Migration and Agricultural Expansion: An Impending Threat to the Maya Biosphere Reserve
Sader, Steven; Reining, Conard; Sever, Thomas L.; Soza, Carlos
1997-01-01
Evidence is presented of the current threats to the Maya Biosphere Reserve in northern Guatemala as derived through time-series Landsat Thematic Mapper observations and analysis. Estimates of deforestation rates and trends are examined for different management units within the reserve and buffer zones. The satellite imagery was used to quantify and monitor rates, patterns, and trends of forest clearing during a time period corresponding to new road construction and significant human migration into the newly accessible forest region. Satellite imagery is appropriate technology in a vast and remote tropical region where aerial photography and extensive field-based methods are not cost-effective and current, timely data is essential for establishing conservation priorities.
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Patterns of migration and risks associated with leprosy among migrants in Maranhão, Brazil.
Directory of Open Access Journals (Sweden)
Christine Murto
Full Text Available Leprosy remains a public health problem in Brazil with new case incidence exceeding World Health Organization (WHO goals in endemic clusters throughout the country. Migration can facilitate movement of disease between endemic and non-endemic areas, and has been considered a possible factor in continued leprosy incidence in Brazil. A study was conducted to investigate migration as a risk factor for leprosy. The study had three aims: (1 examine past five year migration as a risk factor for leprosy, (2 describe and compare geographic and temporal patterns of migration among past 5-year migrants with leprosy and a control group, and (3 examine social determinants of health associated with leprosy among past 5-year migrants. The study implemented a matched case-control design and analysis comparing individuals newly diagnosed with leprosy (n = 340 and a clinically unapparent control group (n = 340 without clinical signs of leprosy, matched for age, sex and location in four endemic municipalities in the state of Maranhão, northeastern Brazil. Fishers exact test was used to conduct bivariate analyses. A multivariate logistic regression analysis was employed to control for possible confounding variables. Eighty cases (23.5% migrated 5-years prior to diagnosis, and 55 controls (16.2% migrated 5-years prior to the corresponding case diagnosis. Past 5 year migration was found to be associated with leprosy (OR: 1.59; 95% CI 1.07-2.38; p = 0.02, and remained significantly associated with leprosy after controlling for leprosy contact in the family, household, and family/household contact. Poverty, as well as leprosy contact in the family, household and other leprosy contact, was associated with leprosy among past 5-year migrants in the bivariate analysis. Alcohol consumption was also associated with leprosy, a relevant risk factor in susceptibility to infection that should be explored in future research. Our findings provide insight into patterns
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Patterns of Migration and Risks Associated with Leprosy among Migrants in Maranhão, Brazil
Murto, Christine; Chammartin, Frédérique; Schwarz, Karolin; da Costa, Lea Marcia Melo; Kaplan, Charles; Heukelbach, Jorg
2013-01-01
Leprosy remains a public health problem in Brazil with new case incidence exceeding World Health Organization (WHO) goals in endemic clusters throughout the country. Migration can facilitate movement of disease between endemic and non-endemic areas, and has been considered a possible factor in continued leprosy incidence in Brazil. A study was conducted to investigate migration as a risk factor for leprosy. The study had three aims: (1) examine past five year migration as a risk factor for leprosy, (2) describe and compare geographic and temporal patterns of migration among past 5-year migrants with leprosy and a control group, and (3) examine social determinants of health associated with leprosy among past 5-year migrants. The study implemented a matched case-control design and analysis comparing individuals newly diagnosed with leprosy (n = 340) and a clinically unapparent control group (n = 340) without clinical signs of leprosy, matched for age, sex and location in four endemic municipalities in the state of Maranhão, northeastern Brazil. Fishers exact test was used to conduct bivariate analyses. A multivariate logistic regression analysis was employed to control for possible confounding variables. Eighty cases (23.5%) migrated 5-years prior to diagnosis, and 55 controls (16.2%) migrated 5-years prior to the corresponding case diagnosis. Past 5 year migration was found to be associated with leprosy (OR: 1.59; 95% CI 1.07–2.38; p = 0.02), and remained significantly associated with leprosy after controlling for leprosy contact in the family, household, and family/household contact. Poverty, as well as leprosy contact in the family, household and other leprosy contact, was associated with leprosy among past 5-year migrants in the bivariate analysis. Alcohol consumption was also associated with leprosy, a relevant risk factor in susceptibility to infection that should be explored in future research. Our findings provide insight into patterns of
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Korpi, Martin; Clark, William A W
2017-05-01
By modelling the distribution of percentage income gains for movers in Sweden, using multinomial logistic regression, this paper shows that those receiving large pecuniary returns from migration are primarily those moving to the larger metropolitan areas and those with higher education, and that there is much more variability in income gains than what is often assumed in models of average gains to migration. This suggests that human capital models of internal migration often overemphasize the job and income motive for moving, and fail to explore where and when human capital motivated migration occurs.
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Energy Technology Data Exchange (ETDEWEB)
Collins, J.L.
1981-01-01
The people of the southern Peruvian highlands have adapted to a condition of energy scarcity through seasonal migration to lowland areas. In the disrict of Sarata (a fictitious name for a real district on the northeastern shore of Lake Titicaca) people spend three to seven months of every year growing coffee in the Tambopata Valley of the eastern Andes. This migratory pattern, which is hundreds of years old, provides the context for an investigation of human adaptive processes. This study presents models of the flow of energy through high-altitude households and shows that energy is a limiting factor for the population. There are two periods when energy subsidies from lowland regions become crucial to the continued survival of highland households. These are the periods of peak growth and reproduction experienced by households early in their developmental cycles, and times of sharply lowered productivity caused by environmental crises such as drought or killing frosts. Seasonal migration provides the subsidies that households rely on during these periods.
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Temporal patterns of migration and spawning of river herring in coastal Massachusetts
Rosset, Julianne; Roy, Allison; Gahagan, Benjamin I.; Whiteley, Andrew R.; Armstrong, Michael P.; Sheppard, John J.; Jordaan, Adrian
2017-01-01
Migrations of springtime Alewife Alosa pseudoharengus and Blueback Herring A. aestivalis, collectively referred to as river herring, are monitored in many rivers along the Atlantic coast to estimate population sizes. While these estimates give an indication of annual differences in the number of returning adults, links to the subsequent timing and duration of spawning and freshwater juvenile productivity remain equivocal. In this study, we captured juvenile river herring at night in 20 coastal Massachusetts lakes using a purse seine and extracted otoliths to derive daily fish ages and back-calculate spawn dates. Estimates of spawning dates were compared with fishway counts of migrating adults to assess differences in migration timing and the timing and duration of spawning. We observed a distinct delay between the beginning of the adult migration run and the start of spawning, ranging from 7 to 28 d across the 20 lakes. Spawning continued 13–48 d after adults stopped migrating into freshwater, further demonstrating a pronounced delay in spawning following migration. Across the study sites the duration of spawning (43–76 d) was longer but not related to the duration of migration (29–66 d). The extended spawning period is consistent with recent studies suggesting that Alewives are indeterminate spawners. The long duration in freshwater provides the opportunity for top-down (i.e., predation on zooplankton) and bottom-up (i.e., food for avian, fish, and other predators) effects, with implications for freshwater food webs and nutrient cycling. General patterns of spawn timing and duration can be incorporated into population models and used to estimate temporal changes in productivity associated with variable timing and density of spawning river herring in lakes.
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Sun, Mingming; Ye, Mao; Schwab, Arthur P; Li, Xu; Wan, Jinzhong; Wei, Zhong; Wu, Jun; Friman, Ville-Petri; Liu, Kuan; Tian, Da; Liu, Manqiang; Li, Huixin; Hu, Feng; Jiang, Xin
2016-01-01
Landfills are perfect sites to study the effect of human migration on fluctuation of antibiotic resistance genes (ARGs) as they are the final destination of municipal waste. For example, large-scale human migration during the holidays is often accompanied by changes in waste dumping having potential effects on ARG abundance. Three landfills were selected to examine fluctuation in the abundance of fifteen ARGs and Intl1 genes for 14 months in Nanjing, eastern China. Mass human migration, the a...
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Japanese migration in contemporary Japan: economic segmentation and interprefectural migration.
Fukurai, H
1991-01-01
This paper examines the economic segmentation model in explaining 1985-86 Japanese interregional migration. The analysis takes advantage of statistical graphic techniques to illustrate the following substantive issues of interregional migration: (1) to examine whether economic segmentation significantly influences Japanese regional migration and (2) to explain socioeconomic characteristics of prefectures for both in- and out-migration. Analytic techniques include a latent structural equation (LISREL) methodology and statistical residual mapping. The residual dispersion patterns, for instance, suggest the extent to which socioeconomic and geopolitical variables explain migration differences by showing unique clusters of unexplained residuals. The analysis further points out that extraneous factors such as high residential land values, significant commuting populations, and regional-specific cultures and traditions need to be incorporated in the economic segmentation model in order to assess the extent of the model's reliability in explaining the pattern of interprefectural migration.
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Domestic and International Climate Migration from Rural Mexico
Nawrotzki, Raphael J.; Runfola, Daniel M.; Hunter, Lori M.; Riosmena, Fernando
2016-01-01
Evidence is increasing that climate change and variability may influence human migration patterns. However, there is less agreement regarding the type of migration streams most strongly impacted. This study tests whether climate change more strongly impacted international compared to domestic migration from rural Mexico during 1986-99. We employ eight temperature and precipitation-based climate change indices linked to detailed migration histories obtained from the Mexican Migration Project. Results from multilevel discrete-time event-history models challenge the assumption that climate-related migration will be predominantly short distance and domestic, but instead show that climate change more strongly impacted international moves from rural Mexico. The stronger climate impact on international migration may be explained by the self-insurance function of international migration, the presence of strong migrant networks, and climate-related changes in wage difference. While a warming in temperature increased international outmigration, higher levels of precipitation declined the odds of an international move. PMID:28439146
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Domestic and International Climate Migration from Rural Mexico.
Nawrotzki, Raphael J; Runfola, Daniel M; Hunter, Lori M; Riosmena, Fernando
2016-12-01
Evidence is increasing that climate change and variability may influence human migration patterns. However, there is less agreement regarding the type of migration streams most strongly impacted. This study tests whether climate change more strongly impacted international compared to domestic migration from rural Mexico during 1986-99. We employ eight temperature and precipitation-based climate change indices linked to detailed migration histories obtained from the Mexican Migration Project. Results from multilevel discrete-time event-history models challenge the assumption that climate-related migration will be predominantly short distance and domestic, but instead show that climate change more strongly impacted international moves from rural Mexico. The stronger climate impact on international migration may be explained by the self-insurance function of international migration, the presence of strong migrant networks, and climate-related changes in wage difference. While a warming in temperature increased international outmigration, higher levels of precipitation declined the odds of an international move.
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González, Mariela Natacha; de Mello, Wallace; Butler-Browne, Gillian S; Silva-Barbosa, Suse Dayse; Mouly, Vincent; Savino, Wilson; Riederer, Ingo
2017-10-10
The hepatocyte growth factor (HGF) is required for the activation of muscle progenitor cells called satellite cells (SC), plays a role in the migration of proliferating SC (myoblasts), and is present as a soluble factor during muscle regeneration, along with extracellular matrix (ECM) molecules. In this study, we aimed at determining whether HGF is able to interact with ECM proteins, particularly laminin 111 and fibronectin, and to modulate human myoblast migration. We evaluated the expression of the HGF-receptor c-Met, laminin, and fibronectin receptors by immunoblotting, flow cytometry, or immunofluorescence and used Transwell assays to analyze myoblast migration on laminin 111 and fibronectin in the absence or presence of HGF. Zymography was used to check whether HGF could modulate the production of matrix metalloproteinases by human myoblasts, and the activation of MAPK/ERK pathways was evaluated by immunoblotting. We demonstrated that human myoblasts express c-Met, together with laminin and fibronectin receptors. We observed that human laminin 111 and fibronectin have a chemotactic effect on myoblast migration, and this was synergistically increased when low doses of HGF were added. We detected an increase in MMP-2 activity in myoblasts treated with HGF. Conversely, MMP-2 inhibition decreased the HGF-associated stimulation of cell migration triggered by laminin or fibronectin. HGF treatment also induced in human myoblasts activation of MAPK/ERK pathways, whose specific inhibition decreased the HGF-associated stimulus of cell migration triggered by laminin 111 or fibronectin. We demonstrate that HGF induces ERK phosphorylation and MMP production, thus stimulating human myoblast migration on ECM molecules. Conceptually, these data state that the mechanisms involved in the migration of human myoblasts comprise both soluble and insoluble moieties. This should be taken into account to optimize the design of therapeutic cell transplantation strategies by improving
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Early modern human dispersal from Africa: genomic evidence for multiple waves of migration.
Tassi, Francesca; Ghirotto, Silvia; Mezzavilla, Massimo; Vilaça, Sibelle Torres; De Santi, Lisa; Barbujani, Guido
2015-01-01
Anthropological and genetic data agree in indicating the African continent as the main place of origin for anatomically modern humans. However, it is unclear whether early modern humans left Africa through a single, major process, dispersing simultaneously over Asia and Europe, or in two main waves, first through the Arab Peninsula into southern Asia and Oceania, and later through a northern route crossing the Levant. Here, we show that accurate genomic estimates of the divergence times between European and African populations are more recent than those between Australo-Melanesia and Africa and incompatible with the effects of a single dispersal. This difference cannot possibly be accounted for by the effects of either hybridization with archaic human forms in Australo-Melanesia or back migration from Europe into Africa. Furthermore, in several populations of Asia we found evidence for relatively recent genetic admixture events, which could have obscured the signatures of the earliest processes. We conclude that the hypothesis of a single major human dispersal from Africa appears hardly compatible with the observed historical and geographical patterns of genome diversity and that Australo-Melanesian populations seem still to retain a genomic signature of a more ancient divergence from Africa.
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Zhang, Guotao; Zhang, Shangfeng; Li, Yuan
2015-04-01
The channels of deep-water submarine fan under Niger delta slope are characterized by large dimensions special deposition positions and complex formation processes, its geographical location and sedimentary environment also hinder the research and exploration development. According to the strata slicing, RMS amplitude attribute and other techniques, we exhibit the platforms patterns of channels at different period, and based on the analysis of internal architecture and deformation history of channel-leveed systems, migration and evolution process of channel systems could be understood accurately. A great quantity of isolated channels develop in middle Miocene and aggrading streams in late Miocene, which generating because of large scale of turbidity caused by the drop of second order sea-level, which characterized by vertical accretion at smooth channel, while vertical accretion and lateral migration at bend. Evolution of channel systems can be divided into three stages: the initial erosion, erosion and filling alternately, and abandoned stage. With these three stages, the sinuosity of channel change from moderate to high, then decrease. Incision and filling of channels, being during the three development phases, is the driving force of meander-loops migration, which promote three kinds of migration patterns: lateral, down-system and combination migration. The research provides theoretical basis for high-precision prediction and evaluation of deep-water reservoir.
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Hopcraft, J. Grant C.; Morales, J. M.; Beyer, H. L.; Borner, Markus; Mwangomo, Ephraim; Sinclair, A. R. E.; Olff, Han; Haydon, Daniel T.
Large-herbivore migrations occur across gradients of food quality or food abundance that are generally determined by underlying geographic patterns in rainfall, elevation, or latitude, in turn causing variation in the degree of interspecific competition and the exposure to predators. However, the
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Residency Patterns and Secondary Migration of Refugees: A State of the Information Paper.
Forbes, Susan
This paper synthesizes available research regarding the residence patterns of refugees in the United States. Information is presented on both initial placement and secondary migration. The first section traces the evolution of U.S. policy and outcomes from 1945 to the start of the Indochinese resettlement program in 1975. The second section…
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Migration and adaptation to climate change
Energy Technology Data Exchange (ETDEWEB)
Tacoli, Cecilia
2007-11-15
Climate change is having an undeniable impact on many human systems and behaviours, including population mobility. This is hardly surprising: migration is an adaptive response to changes in people's circumstances. Yet environmental factors are not the whole story. Socio-economic, political and cultural factors are also closely linked to population movement, and heavily influence vulnerability to both direct and indirect impacts of climate change. Shifts in migration patterns are a strategy of adaptation to complex transformations, and recognising and accommodating this is key in policies for sustainable development and poverty reduction in the context of growing environmental stress.
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Migrating microbes: what pathogens can tell us about population movements and human evolution.
Houldcroft, Charlotte J; Ramond, Jean-Baptiste; Rifkin, Riaan F; Underdown, Simon J
2017-08-01
The biology of human migration can be observed from the co-evolutionary relationship with infectious diseases. While many pathogens are brief, unpleasant visitors to human bodies, others have the ability to become life-long human passengers. The story of a pathogen's genetic code may, therefore, provide insight into the history of its human host. The evolution and distribution of disease in Africa is of particular interest, because of the deep history of human evolution in Africa, the presence of a variety of non-human primates, and tropical reservoirs of emerging infectious diseases. This study explores which pathogens leave traces in the archaeological record, and whether there are realistic prospects that these pathogens can be recovered from sub-Saharan African archaeological contexts. Three stories are then presented of germs on a journey. The first is the story of HIV's spread on the back of colonialism and the railway networks over the last 150 years. The second involves the spread of Schistosoma mansoni, a parasite which shares its history with the trans-Atlantic slave trade and the origins of fresh-water fishing. Finally, we discuss the tantalising hints of hominin migration and interaction found in the genome of human herpes simplex virus 2. Evidence from modern African pathogen genomes can provide data on human behaviour and migration in deep time and contribute to the improvement of human quality-of-life and longevity.
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Migration of fresh and cryopreserved human spermatozoa in polyacrylamide gel.
Goldstein, M C; Wix, L S; Foote, R H; Feldschuh, R; Feldschuh, J
1982-05-01
The ability of freshly collected and frozen human spermatozoa to migrate in round capillary tubes containing specially formulated polyacrylamide gel was investigated, using 33 ejaculates from 27 donors. Each semen sample was divided; one portion was left undiluted, and the other portion was diluted to 50 x 10(6) sperm/ml. Glycerol was used as the cryoprotectant. The percentage of motile sperm cells was determined before and after freezing. Fresh semen contained a higher percentage of motile cells, which migrated farther than those of cryopreserved-thawed semen. Various correlations between the percentage of motile sperm and migration distance ranged from 0.57 to 0.62. There was a low positive correlation of migration distance with sperm cell concentration per milliliter, r = 0.25 to 0.34; and thus adjusting semen samples to a standard sperm concentration improved the accuracy of the test only slightly. The regression coefficient of migration distance on the percentage of motile sperm in fresh semen was 0.65, indicating that for each 10% increase in sperm motility, migration distance is predicted to increase 6.5 mm. Five batches of polyacrylamide gel gave uniform results, and the application of this stable gel to fertility investigations is discussed.
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Spatio-temporal migration patterns of Pacific salmon smolts in rivers and coastal marine waters.
Directory of Open Access Journals (Sweden)
Michael C Melnychuk
Full Text Available BACKGROUND: Migrations allow animals to find food resources, rearing habitats, or mates, but often impose considerable predation risk. Several behavioural strategies may reduce this risk, including faster travel speed and taking routes with shorter total distance. Descriptions of the natural range of variation in migration strategies among individuals and populations is necessary before the ecological consequences of such variation can be established. METHODOLOGY/PRINCIPAL FINDINGS: Movements of tagged juvenile coho, steelhead, sockeye, and Chinook salmon were quantified using a large-scale acoustic tracking array in southern British Columbia, Canada. Smolts from 13 watersheds (49 watershed/species/year combinations were tagged between 2004-2008 and combined into a mixed-effects model analysis of travel speed. During the downstream migration, steelhead were slower on average than other species, possibly related to freshwater residualization. During the migration through the Strait of Georgia, coho were slower than steelhead and sockeye, likely related to some degree of inshore summer residency. Hatchery-reared smolts were slower than wild smolts during the downstream migration, but after ocean entry, average speeds were similar. In small rivers, downstream travel speed increased with body length, but in the larger Fraser River and during the coastal migration, average speed was independent of body length. Smolts leaving rivers located towards the northern end of the Strait of Georgia ecosystem migrated strictly northwards after ocean entry, but those from rivers towards the southern end displayed split-route migration patterns within populations, with some moving southward. CONCLUSIONS/SIGNIFICANCE: Our results reveal a tremendous diversity of behavioural migration strategies used by juvenile salmon, across species, rearing histories, and habitats, as well as within individual populations. During the downstream migration, factors that had strong
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Natural disasters and human mobility
Mbaye, L.; Zimmermann, K.
2016-01-01
This paper reviews the effect of natural disasters on human mobility or migration. Although there is an increase of natural disasters and migration recently and more patterns to observe, the relationship remains complex. While some authors find that disasters increase migration, others show that
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Spatial patterns of close relationships across the lifespan
Jo, Hang-Hyun; Saramäki, Jari; Dunbar, Robin I. M.; Kaski, Kimmo
2014-11-01
The dynamics of close relationships is important for understanding the migration patterns of individual life-courses. The bottom-up approach to this subject by social scientists has been limited by sample size, while the more recent top-down approach using large-scale datasets suffers from a lack of detail about the human individuals. We incorporate the geographic and demographic information of millions of mobile phone users with their communication patterns to study the dynamics of close relationships and its effect in their life-course migration. We demonstrate how the close age- and sex-biased dyadic relationships are correlated with the geographic proximity of the pair of individuals, e.g., young couples tend to live further from each other than old couples. In addition, we find that emotionally closer pairs are living geographically closer to each other. These findings imply that the life-course framework is crucial for understanding the complex dynamics of close relationships and their effect on the migration patterns of human individuals.
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Trafficking in human beings as a specific form of women's migration
Directory of Open Access Journals (Sweden)
Mrvić-Petrović Nataša
2002-01-01
Full Text Available The author is analyzing trafficking in human beings as a specific form of women's (illegal migration. The author is presenting detailed analysis of the international standards and recent activities of different international organizations (UN, Council of Europe, European Community, OSCE, concerning prevention of trafficking in human beings, regulation of foreign migrants' status and protection of victims of trafficking. Starting from the analysis of international documents and national legislations dealing with migration and prostitution, the author is proposing changes of existing domestic laws concerning movement and residence of foreigners. The aim of such changes is to harmonize our legislation with international standards and obligations accepted by signing the Palermo Convention.
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Migration signatures across the decades: Net migration by age in U.S. counties, 1950-2010
Directory of Open Access Journals (Sweden)
Richelle L. Winkler
2015-05-01
Full Text Available Background: Migration is the primary population redistribution process in the United States. Selective migration by age, race/ethnic group, and spatial location governs population integration, affects community and economic development, contributes to land use change, and structures service needs. Objective: Delineate historical net migration patterns by age, race/ethnic, and rural-urban dimensions for United States counties. Methods: Net migration rates by age for all US counties are aggregated from 1950−2010, summarized by rural-urban location and compared to explore differential race/ethnic patterns of age-specific net migration over time. Results: We identify distinct age-specific net migration 'signatures' that are consistent over time within county types, but different by rural-urban location and race/ethnic group. There is evidence of moderate population deconcentration and diminished racial segregation between 1990 and 2010. This includes a net outflow of Blacks from large urban core counties to suburban and smaller metropolitan counties, continued Hispanic deconcentration, and a slowdown in White counterurbanization. Conclusions: This paper contributes to a fuller understanding of the complex patterns of migration that have redistributed the U.S. population over the past six decades. It documents the variability in county age-specific net migration patterns both temporally and spatially, as well as the longitudinal consistency in migration signatures among county types and race/ethnic groups.
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Pattern of childhood neuronal migrational disorders in Oman
International Nuclear Information System (INIS)
Koul, Roshan L.; Alfuitasi, Amna M.; Javad, Hashim; Sankhla, Dilip K.; William, Ranjan R.
2009-01-01
To record the pattern of different neuronal migrational disorders (NMD) and their associated neurological conditions. The data were collected at the Child Neurology Services of Sultan Qaboos University Hospital, Oman, from January 1993 to September 2006 from all children with psychomotor delay and epilepsy, who underwent brain imaging (mostly MRI). The MR imaging was used for the diagnosis of a neuronal migration anomaly. There were 86 cases of NMD. Corpus callosum agenesis and lissencephaly/pachygyria formed the major group. There were 48 cases of corpus callosum agenesis, and 16 cases of lissencephaly/pachygyria. Other disorders were 10 cases of heterotopias, 5 schizencephaly, 3 holoprosencephaly, 2 polymicrogyria, and one each of hemimegalencephaly, and hydranencephaly. Developmental delay was the most common associated finding noted in 80 (93%) cases. Sixty-seven (77.9%) cases had motor deficit. Forty out of 86 (46.5%) cases had epilepsy. Partial/partial complex seizures were the most common at 13 out of 40 (32.5%). Syndromic seizures were seen in 11 out of 40 (27.5%) cases. The seizures were controlled in only 3/40 (7.5%) cases. The NMD constitute a significant number of child neurology patients with psychomotor delay and intractable epilepsy. Exogenic and genetic factors affecting the early embryonic and fetal development from sixth to twenty-sixth weeks of gestation result in NMD. Recent genetic studies are defining the underlying mechanism and these studies will help in early diagnosis and possible prevention of NMD. (author)
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Iptakalim inhibits PDGF-BB-induced human airway smooth muscle cells proliferation and migration
Energy Technology Data Exchange (ETDEWEB)
Liu, Wenrui; Kong, Hui; Zeng, Xiaoning; Wang, Jingjing; Wang, Zailiang; Yan, Xiaopei; Wang, Yanli; Xie, Weiping, E-mail: wpxie@njmu.edu.cn; Wang, Hong, E-mail: hongwang@njmu.edu.cn
2015-08-15
Chronic airway diseases are characterized by airway remodeling which is attributed partly to the proliferation and migration of airway smooth muscle cells (ASMCs). ATP-sensitive potassium (K{sub ATP}) channels have been identified in ASMCs. Mount evidence has suggested that K{sub ATP} channel openers can reduce airway hyperresponsiveness and alleviate airway remodeling. Opening K{sup +} channels triggers K{sup +} efflux, which leading to membrane hyperpolarization, preventing Ca{sup 2+}entry through closing voltage-operated Ca{sup 2+} channels. Intracellular Ca{sup 2+} is the most important regulator of muscle contraction, cell proliferation and migration. K{sup +} efflux decreases Ca{sup 2+} influx, which consequently influences ASMCs proliferation and migration. As a K{sub ATP} channel opener, iptakalim (Ipt) has been reported to restrain the proliferation of pulmonary arterial smooth muscle cells (PASMCs) involved in vascular remodeling, while little is known about its impact on ASMCs. The present study was designed to investigate the effects of Ipt on human ASMCs and the mechanisms underlying. Results obtained from cell counting kit-8 (CCK-8), flow cytometry and 5-ethynyl-2′-deoxyuridine (EdU) incorporation showed that Ipt significantly inhibited platelet-derived growth factor (PDGF)-BB-induced ASMCs proliferation. ASMCs migration induced by PDGF-BB was also suppressed by Ipt in transwell migration and scratch assay. Besides, the phosphorylation of Ca{sup 2+}/calmodulin-dependent kinase II (CaMKII), extracellular regulated protein kinases 1/2 (ERK1/2), protein kinase B (Akt), and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) were as well alleviated by Ipt administration. Furthermore, we found that the inhibition of Ipt on the PDGF-BB-induced proliferation and migration in human ASMCs was blocked by glibenclamide (Gli), a selective K{sub ATP} channel antagonist. These findings provide a strong evidence to support that Ipt
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Barhanpurkar-Naik, Amruta; Mhaske, Suhas T; Pote, Satish T; Singh, Kanupriya; Wani, Mohan R
2017-07-14
Mesenchymal stem cells (MSCs) represent an important source for cell therapy in regenerative medicine. MSCs have shown promising results for repair of damaged tissues in various degenerative diseases in animal models and also in human clinical trials. However, little is known about the factors that could enhance the migration and tissue-specific engraftment of exogenously infused MSCs for successful regenerative cell therapy. Previously, we have reported that interleukin-3 (IL-3) prevents bone and cartilage damage in animal models of rheumatoid arthritis and osteoarthritis. Also, IL-3 promotes the differentiation of human MSCs into functional osteoblasts and increases their in-vivo bone regenerative potential in immunocompromised mice. However, the role of IL-3 in migration of MSCs is not yet known. In the present study, we investigated the role of IL-3 in migration of human MSCs under both in-vitro and in-vivo conditions. MSCs isolated from human bone marrow, adipose and gingival tissues were used for in-vitro cell migration, motility and wound healing assays in the presence or absence of IL-3. The effect of IL-3 preconditioning on expression of chemokine receptors and integrins was examined by flow cytometry and real-time PCR. The in-vivo migration of IL-3-preconditioned MSCs was investigated using a subcutaneous matrigel-releasing stromal cell-derived factor-1 alpha (SDF-1α) model in immunocompromised mice. We observed that human MSCs isolated from all three sources express IL-3 receptor-α (IL-3Rα) both at gene and protein levels. IL-3 significantly enhances in-vitro migration, motility and wound healing abilities of MSCs. Moreover, IL-3 preconditioning upregulates expression of chemokine (C-X-C motif) receptor 4 (CXCR4) on MSCs, which leads to increased migration of cells towards SDF-1α. Furthermore, CXCR4 antagonist AMD3100 decreases the migration of IL-3-treated MSCs towards SDF-1α. Importantly, IL-3 also induces in-vivo migration of MSCs towards
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Kuragano, Masahiro; Murakami, Yota; Takahashi, Masayuki
2018-03-25
Nonmuscle myosin II (NMII) plays an essential role in directional cell migration. In this study, we investigated the roles of NMII isoforms (NMIIA and NMIIB) in the migration of human embryonic lung fibroblasts, which exhibit directionally persistent migration in an intrinsic manner. NMIIA-knockdown (KD) cells migrated unsteadily, but their direction of migration was approximately maintained. By contrast, NMIIB-KD cells occasionally reversed their direction of migration. Lamellipodium-like protrusions formed in the posterior region of NMIIB-KD cells prior to reversal of the migration direction. Moreover, NMIIB KD led to elongation of the posterior region in migrating cells, probably due to the lack of load-bearing stress fibers in this area. These results suggest that NMIIA plays a role in steering migration by maintaining stable protrusions in the anterior region, whereas NMIIB plays a role in maintenance of front-rear polarity by preventing aberrant protrusion formation in the posterior region. These distinct functions of NMIIA and NMIIB might promote intrinsic and directed migration of normal human fibroblasts. Copyright © 2018 Elsevier Inc. All rights reserved.
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MiR-1254 inhibits proliferation, migration and invasion of human ...
African Journals Online (AJOL)
MiR-1254 inhibits proliferation, migration and invasion of human brain tumour cell lines. ... The transcripts were analysed by real-time polymerase chain reaction (RT-PCR) ... Over-expression of miR- 1254 also led to significant decrease in cell ...
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Directory of Open Access Journals (Sweden)
Nando Sigona
2012-06-01
Full Text Available The Arab Spring has not radically transformed migration patterns in the Mediterranean, and the label ‘migration crisis’ does not do justice to the composite and stratified reality.
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Effects of conditioned medium from LL-37 treated adipose stem cells on human fibroblast migration.
Yang, Eun-Jung; Bang, Sa-Ik
2017-07-01
Adipose stem cell-conditioned medium may promote human dermal fibroblast (HDF) proliferation and migration by activating paracrine peptides during the re-epithelization phase of wound healing. Human antimicrobial peptide LL-37 is upregulated in the skin epithelium as part of the normal response to injury. The effects of conditioned medium (CM) from LL-37 treated adipose stem cells (ASCs) on cutaneous wound healing, including the mediation of fibroblast migration, remain to be elucidated, therefore the aim of the present study was to determine how ASCs would react to an LL-37-rich microenvironment and if CM from LL-37 treated ASCs may influence the migration of HDFs. The present study conducted migration assays with HDFs treated with CM from LL-37 treated ASCs. Expression of CXC chemokine receptor 4 (CXCR4), which controls the recruitment of HDFs, was analyzed at the mRNA and protein levels. To further characterize the stimulatory effects of LL-37 on ASCs, the expression of stromal cell-derived factor-1α (SDF-1α), a CXC chemokine, was investigated. CM from LL-37-treated ASCs induced migration of HDFs in a time- and dose-dependent manner, with a maximum difference in migration observed 24 h following stimulation with LL-37 at a concentration of 10 µg/ml. The HDF migration and the expression of CXCR4 in fibroblasts was markedly increased upon treatment with CM from LL-37-treated ASCs compared with CM from untreated ASCs. SDF-1α expression was markedly increased in CM from LL-37 treated ASCs. It was additionally observed that SDF-1α blockade significantly reduced HDF migration. These findings suggest the feasibility of CM from LL-37-treated ASCs as a potential therapeutic for human dermal fibroblast migration.
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Corti, G.; Bonini, M.; Sokoutis, D.; Innocenti, F.; Manetti, P.; Cloetingh, S.A.P.L.; Mulugeta, G.
2004-01-01
Small-scale centrifuge models were used to investigate the role of continental rift structure in controlling patterns of magma migration and emplacement. Experiments considered the reactivation of weakness zones in the lower crust and the presence of magma at Moho depths. Results suggest that
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Bai, Ming; Grieshaber-Bouyer, Ricardo; Wang, Junxia; Schmider, Angela B; Wilson, Zachary S; Zeng, Liling; Halyabar, Olha; Godin, Matthew D; Nguyen, Hung N; Levescot, Anaïs; Cunin, Pierre; Lefort, Craig T; Soberman, Roy J; Nigrovic, Peter A
2017-11-09
CD177 is a glycosylphosphatidylinositol (GPI)-anchored protein expressed by a variable proportion of human neutrophils that mediates surface expression of the antineutrophil cytoplasmic antibody antigen proteinase 3. CD177 associates with β2 integrins and recognizes platelet endothelial cell adhesion molecule 1 (PECAM-1), suggesting a role in neutrophil migration. However, CD177 pos neutrophils exhibit no clear migratory advantage in vivo, despite interruption of in vitro transendothelial migration by CD177 ligation. We sought to understand this paradox. Using a PECAM-1-independent transwell system, we found that CD177 pos and CD177 neg neutrophils migrated comparably. CD177 ligation selectively impaired migration of CD177 pos neutrophils, an effect mediated through immobilization and cellular spreading on the transwell membrane. Correspondingly, CD177 ligation enhanced its interaction with β2 integrins, as revealed by fluorescence lifetime imaging microscopy, leading to integrin-mediated phosphorylation of Src and extracellular signal-regulated kinase (ERK). CD177-driven cell activation enhanced surface β2 integrin expression and affinity, impaired internalization of integrin attachments, and resulted in ERK-mediated attenuation of chemokine signaling. We conclude that CD177 signals in a β2 integrin-dependent manner to orchestrate a set of activation-mediated mechanisms that impair human neutrophil migration. © 2017 by The American Society of Hematology.
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The Water Suitcase of Migrants: Assessing Virtual Water Fluxes Associated to Human Migration.
Metulini, Rodolfo; Tamea, Stefania; Laio, Francesco; Riccaboni, Massimo
2016-01-01
Disentangling the relations between human migrations and water resources is relevant for food security and trade policy in water-scarce countries. It is commonly believed that human migrations are beneficial to the water endowments of origin countries for reducing the pressure on local resources. We show here that such belief is over-simplistic. We reframe the problem by considering the international food trade and the corresponding virtual water fluxes, which quantify the water used for the production of traded agricultural commodities. By means of robust analytical tools, we show that migrants strengthen the commercial links between countries, triggering trade fluxes caused by food consumption habits persisting after migration. Thus migrants significantly increase the virtual water fluxes and the use of water in the countries of origin. The flux ascribable to each migrant, i.e. the "water suitcase", is found to have increased from 321 m3/y in 1990 to 1367 m3/y in 2010. A comparison with the water footprint of individuals shows that where the water suitcase exceeds the water footprint of inhabitants, migrations turn out to be detrimental to the water endowments of origin countries, challenging the common perception that migrations tend to relieve the pressure on the local (water) resources of origin countries.
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RSA migration of total knee replacements.
Pijls, Bart G; Plevier, José W M; Nelissen, Rob G H H
2018-06-01
Purpose - We performed a systematic review and meta-analyses to evaluate the early and long-term migration patterns of tibial components of TKR of all known RSA studies. Methods - Migration pattern was defined as at least 2 postoperative RSA follow-up moments. Maximal total point motion (MTPM) at 6 weeks, 3 months, 6 months, 1 year, 2 years, 5 years, and 10 years were considered. Results - The literature search yielded 1,167 hits of which 53 studies were included, comprising 111 study groups and 2,470 knees. The majority of the early migration occurred in the first 6 months postoperatively followed by a period of stability, i.e., no or very little migration. Cemented and uncemented tibial components had different migration patterns. For cemented tibial components there was no difference in migration between all-poly and metal-backed components, between mobile bearing and fixed bearing, between cruciate retaining and posterior stabilized. Furthermore, no difference existed between TKR measured with model-based RSA or marker-based RSA methods. For uncemented TKR there was some variation in migration with the highest migration for uncoated TKR. Interpretation - The results from this meta-analysis on RSA migration of TKR are in line with both the survival analyses results from joint registries of these TKRs as well as revision rates results from meta-analyses, thus providing further proof for the association between early migration and late revision for loosening. The pooled migration patterns can be used both as benchmarks and for defining migration thresholds for future evaluation of new TKR.
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Directory of Open Access Journals (Sweden)
Zilkens C
2011-03-01
Full Text Available Abstract The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA. One hundred 'and one (94.4% acetabular components did not show significant migration of more than 1 mm. Six (5.6% implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous- coated acetabular components for primary THA does not prevent cup migration.
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Chicken HOXA3 Gene: Its Expression Pattern and Role in Branchial Nerve Precursor Cell Migration
Watari-Goshima, Natsuko; Chisaka, Osamu
2011-01-01
In vertebrates, the proximal and distal sensory ganglia of the branchial nerves are derived from neural crest cells (NCCs) and placodes, respectively. We previously reported that in Hoxa3 knockout mouse embryos, NCCs and placode-derived cells of the glossopharyngeal nerve were defective in their migration. In this report, to determine the cell-type origin for this Hoxa3 knockout phenotype, we blocked the expression of the gene with antisense morpholino oligonucleotides (MO) specifically in either NCCs/neural tube or placodal cells of chicken embryos. Our results showed that HOXA3 function was required for the migration of the epibranchial placode-derived cells and that HOXA3 regulated this cell migration in both NCCs/neural tube and placodal cells. We also report that the expression pattern of chicken HOXA3 was slightly different from that of mouse Hoxa3. PMID:21278919
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Analysis of gas migration patterns in fractured coal rocks under actual mining conditions
Directory of Open Access Journals (Sweden)
Gao Mingzhong
2017-01-01
Full Text Available Fracture fields in coal rocks are the main channels for gas seepage, migration, and extraction. The development, evolution, and spatial distribution of fractures in coal rocks directly affect the permeability of the coal rock as well as gas migration and flow. In this work, the Ji-15-14120 mining face at the No. 8 Coal Mine of Pingdingshan Tian’an Coal Mining Co. Ltd., Pingdingshan, China, was selected as the test site to develop a full-parameter fracture observation instrument and a dynamic fracture observation technique. The acquired video information of fractures in the walls of the boreholes was vectorized and converted to planarly expanded images on a computer-aided design platform. Based on the relative spatial distances between the openings of the boreholes, simultaneous planar images of isolated fractures in the walls of the boreholes along the mining direction were obtained from the boreholes located at various distances from the mining face. Using this information, a 3-D fracture network under mining conditions was established. The gas migration pattern was calculated using a COMSOL computation platform. The results showed that between 10 hours and 1 day the fracture network controlled the gas-flow, rather than the coal seam itself. After one day, the migration of gas was completely controlled by the fractures. The presence of fractures in the overlying rock enables the gas in coal seam to migrate more easily to the surrounding rocks or extraction tunnels situated relatively far away from the coal rock. These conclusions provide an important theoretical basis for gas extraction.
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Bourget, Jean-Michel; Kérourédan, Olivia; Medina, Manuela; Rémy, Murielle; Thébaud, Noélie Brunehilde; Bareille, Reine; Chassande, Olivier; Amédée, Joëlle; Catros, Sylvain; Devillard, Raphaël
2016-01-01
Tissue engineering of large organs is currently limited by the lack of potent vascularization in vitro . Tissue-engineered bone grafts can be prevascularized in vitro using endothelial cells (ECs). The microvascular network architecture could be controlled by printing ECs following a specific pattern. Using laser-assisted bioprinting, we investigated the effect of distance between printed cell islets and the influence of coprinted mesenchymal cells on migration. When printed alone, ECs spread out evenly on the collagen hydrogel, regardless of the distance between cell islets. However, when printed in coculture with mesenchymal cells by laser-assisted bioprinting, they remained in the printed area. Therefore, the presence of mesenchymal cell is mandatory in order to create a pattern that will be conserved over time. This work describes an interesting approach to study cell migration that could be reproduced to study the effect of trophic factors.
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Long term file migration. Part I: file reference patterns
International Nuclear Information System (INIS)
Smith, A.J.
1978-08-01
In most large computer installations, files are moved between on-line disk and mass storage (tape, integrated mass storage device) either automatically by the system or specifically at the direction of the user. This is the first of two papers which study the selection of algorithms for the automatic migration of files between mass storage and disk. The use of the text editor data sets at the Stanford Linear Accelerator Center (SLAC) computer installation is examined through the analysis of thirteen months of file reference data. Most files are used very few times. Of those that are used sufficiently frequently that their reference patterns may be examined, about a third show declining rates of reference during their lifetime; of the remainder, very few (about 5%) show correlated interreference intervals, and interreference intervals (in days) appear to be more skewed than would occur with the Bernoulli process. Thus, about two-thirds of all sufficiently active files appear to be referenced as a renewal process with a skewed interreference distribution. A large number of other file reference statistics (file lifetimes, interference distributions, moments, means, number of uses/file, file sizes, file rates of reference, etc.) are computed and presented. The results are applied in the following paper to the development and comparative evaluation of file migration algorithms. 17 figures, 13 tables
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Late Pleistocene climate drivers of early human migration
Timmermann, Axel; Friedrich, Tobias
2016-10-01
On the basis of fossil and archaeological data it has been hypothesized that the exodus of Homo sapiens out of Africa and into Eurasia between ~50-120 thousand years ago occurred in several orbitally paced migration episodes. Crossing vegetated pluvial corridors from northeastern Africa into the Arabian Peninsula and the Levant and expanding further into Eurasia, Australia and the Americas, early H. sapiens experienced massive time-varying climate and sea level conditions on a variety of timescales. Hitherto it has remained difficult to quantify the effect of glacial- and millennial-scale climate variability on early human dispersal and evolution. Here we present results from a numerical human dispersal model, which is forced by spatiotemporal estimates of climate and sea level changes over the past 125 thousand years. The model simulates the overall dispersal of H. sapiens in close agreement with archaeological and fossil data and features prominent glacial migration waves across the Arabian Peninsula and the Levant region around 106-94, 89-73, 59-47 and 45-29 thousand years ago. The findings document that orbital-scale global climate swings played a key role in shaping Late Pleistocene global population distributions, whereas millennial-scale abrupt climate changes, associated with Dansgaard-Oeschger events, had a more limited regional effect.
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Gong, Fang; Xu, Jun; Fujishiro, Kaori; Takeuchi, David T
2011-12-01
The relationship between human agency and health is an important yet under-researched topic. This study uses a life course perspective to examine how human agency (measured by voluntariness, migratory reasons, and planning) and timing (measured by age at immigration) affect mental health outcomes among Asian immigrants in the United States. Data from the National Latino and Asian American Study showed that Asian immigrants (n=1491) with multiple strong reasons to migrate were less likely to suffer from mental health problems (i.e., psychological distress and psychiatric disorders in the past 12 months) than those without clear goals. Moreover, Asian immigrants with adequate migratory planning had lower levels of distress and lower rates of 12-month psychiatric disorders than those with poorly planned migration. Compared with migrants of the youngest age category (six or younger), those who migrated during preteen and adolescent years without clear goals had higher levels of psychological distress, and those who migrated during adulthood (25 years or older) were less likely to suffer from recent depressive disorders (with the exception of those migrating for life-improving goals). Furthermore, we found that well-planned migration lowered acculturative stress, and multiple strong reasons for migration buffered the negative effect of acculturative stress upon mental health. Findings from this study advance research on immigrant health from the life course perspective by highlighting the effects of exercising human agency during the pre-migration stage upon post-migration mental health. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Liu, L Y; Wang, H; Xenakis, J J; Spencer, L A
2015-07-01
Priming with cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) enhances eosinophil migration and exacerbates the excessive accumulation of eosinophils within the bronchial mucosa of asthmatics. However, mechanisms that drive GM-CSF priming are incompletely understood. Notch signaling is an evolutionarily conserved pathway that regulates cellular processes, including migration, by integrating exogenous and cell-intrinsic cues. This study investigates the hypothesis that the priming-induced enhanced migration of human eosinophils requires the Notch signaling pathway. Using pan Notch inhibitors and newly developed human antibodies that specifically neutralize Notch receptor 1 activation, we investigated a role for Notch signaling in GM-CSF-primed transmigration of human blood eosinophils in vitro and in the airway accumulation of mouse eosinophils in vivo. Notch receptor 1 was constitutively active in freshly isolated human blood eosinophils, and inhibition of Notch signaling or specific blockade of Notch receptor 1 activation during GM-CSF priming impaired priming-enhanced eosinophil transendothelial migration in vitro. Inclusion of Notch signaling inhibitors during priming was associated with diminished ERK phosphorylation, and ERK-MAPK activation was required for GM-CSF priming-induced transmigration. In vivo in mice, eosinophil accumulation within allergic airways was impaired following systemic treatment with Notch inhibitor, or adoptive transfer of eosinophils treated ex vivo with Notch inhibitor. These data identify Notch signaling as an intrinsic pathway central to GM-CSF priming-induced eosinophil tissue migration. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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WNT5A inhibits human dental papilla cell proliferation and migration
International Nuclear Information System (INIS)
Peng, L.; Ye, L.; Dong, G.; Ren, L.B.; Wang, C.L.; Xu, P.; Zhou, X.D.
2009-01-01
WNT proteins are a large family of cysteine-rich secreted molecules that are linked to both canonical and non-canonical signal pathways, and have been implicated in oncogenesis and tissue development. Canonical WNT proteins have been proven to play critical roles in tooth development, while little is known about the role of non-canonical WNT proteins such as WNT5A. In this study, WNT5A was localized to human dental papilla tissue and human dental papilla cells (HDPCs) cultured in vitro, using immunochemistry and RT-PCR. Recombinant adenovirus encoding full-length Wnt5a cDNA was constructed to investigate the biological role of WNT5A on HDPCs. The BrdU incorporation assay, the MTT assay and flow cytometric analysis showed that over-expression of Wnt5a strongly inhibited the proliferation of HDPCs in vitro. Wound healing and transwell migration assays indicated that over-expression of WNT5A reduced migration of HDPCs. In conclusion, our results showed that WNT5A negatively regulates both proliferation and migration of HDPCs, suggesting its important role in odontogenesis via controlling the HDPCs.
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Spontaneous neutrophil migration patterns during sepsis after major burns.
Jones, Caroline N; Moore, Molly; Dimisko, Laurie; Alexander, Andrew; Ibrahim, Amir; Hassell, Bryan A; Warren, H Shaw; Tompkins, Ronald G; Fagan, Shawn P; Irimia, Daniel
2014-01-01
Finely tuned to respond quickly to infections, neutrophils have amazing abilities to migrate fast and efficiently towards sites of infection and inflammation. Although neutrophils ability to migrate is perturbed in patients after major burns, no correlations have yet been demonstrated between altered migration and higher rate of infections and sepsis in these patients when compared to healthy individuals. To probe if such correlations exist, we designed microfluidic devices to quantify the neutrophil migration phenotype with high precision. Inside these devices, moving neutrophils are confined in channels smaller than the neutrophils and forced to make directional decisions at bifurcations and around posts. We employed these devices to quantify neutrophil migration across 18 independent parameters in 74 blood samples from 13 patients with major burns and 3 healthy subjects. Blinded, retrospective analysis of clinical data and neutrophil migration parameters revealed that neutrophils isolated from blood samples collected during sepsis migrate spontaneously inside the microfluidic channels. The spontaneous neutrophil migration is a unique phenotype, typical for patients with major burns during sepsis and often observed one or two days before the diagnosis of sepsis is confirmed. The spontaneous neutrophil migration phenotype is rare in patients with major burns in the absence of sepsis, and is not encountered in healthy individuals. Our findings warrant further studies of neutrophils and their utility for early diagnosing and monitoring sepsis in patients after major burns.
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Directory of Open Access Journals (Sweden)
Elias Ronca
2016-12-01
Full Text Available This study investigated and compared patient migration patterns of persons with spinal cord injury, the general population and persons with morbid obesity, rheumatic conditions and bowel disease, for secondary health conditions, across administrative boundaries in Switzerland. The effects of patient characteristics and health conditions on visiting hospitals outside the residential canton were examined using complete, nationwide, inpatient health records for the years 2010 and 2011. Patients with spinal cord injury were more likely to obtain treatment outside their residential canton as compared to all other conditions. Facilitators of patient migration in persons with spinal cord injury and the general hospital population were private or accidental health insurances covering costs. Barriers of patient migration in persons with spinal cord injury were old age, severe multimorbidity, financial coverage by basic health insurance, and minority language region. Keywords: Spinal cord injury, Patient migration, Health services accessibility, Health care utilization, Inpatient hospital care
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Changing patterns of migration in the Adriatic region.
Schatzer, P
1988-06-01
International migration in the Adriatic countries of Albania, Greece, Italy, San Marino, and Yugoslavia is briefly examined using data from official and other published sources. The main types of migratory movements identified by the author within the region are "1) economically motivated migration (legal and clandestine); 2) immigration of refugees for resettlement; 3) immigration with the scope of final resettlement in a third country (transit movements); [and] 4) return migration by former emigrants." excerpt
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International Nuclear Information System (INIS)
Walenta, S.; Springborn, C.; Zilkens, S.; Groetzebach, B.; Mueller-Klieser, W.
2003-01-01
A high lactate production is a common feature of the majority of malignant tumors. In several independent series of clinical studies we could show that a high lactate content in primary human carcinomas was correlated with a higher incidence of metastases and a reduced patient survival, compared to tumors with a lower lactate content. Since one of the early events in metastasis is the active movement of cancer cells out of the primary tumor site, we have investigated the effect of exogenous lactate on the migratory activity of human cancer cells in vitro. - A 48 well micro chemotaxis chamber was used to quantify the migration of SQ20B and PCI13 cells which were derived from human head and neck squamous cell carcinomas. The chamber consists of bottom and a top Lucite slide, separated by a gelatin covered polycarbonate membrane with pores of 8 μm, where cells eventually migrate through. - In summary, there was a time and concentration dependent unidirectional enhancement of cell migration. For example, cells were incubated in growth medium supplemented with 20 mM L-lactate. On the average, the rate of cell migration was significantly enhanced (p < 0.001) to 139 % for SQ20 and 136 % for PCI cells, compared to untreated control cells (100 %). No effects on cell migration were detected for culture media containing 20 mM D-lactate or 20 mM sodium chloride. These results suggest that an elevated lactate production may not only be an accompanying phenomenon of malignant transformation, but may also play an active part in tumor progression by enhancing cell migration and dissemination of potentially metastatic cells from primary lesions
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Vulnerable to HIV / AIDS. Migration.
Fernandez, I
1998-01-01
This special report discusses the impact of globalization, patterns of migration in Southeast Asia, gender issues in migration, the links between migration and HIV/AIDS, and spatial mobility and social networks. Migrants are particularly marginalized in countries that blame migrants for transmission of infectious and communicable diseases and other social ills. Effective control of HIV/AIDS among migrant and native populations requires a multisectoral approach. Programs should critically review the privatization of health care services and challenge economic models that polarize the rich and the poor, men and women, North and South, and migrant and native. Programs should recognize the equality between locals and migrants in receipt of health services. Countermeasures should have input from migrants in order to reduce the conditions that increase vulnerability to HIV/AIDS. Gender-oriented research is needed to understand women's role in migration. Rapid assessment has obscured the human dimension of migrants' vulnerability to HIV. Condom promotion is not enough. Migration is a major consequence of globalization, which holds the promise, real or imagined, of prosperity for all. Mass migration can be fueled by explosive regional developments. In Southeast Asia, migration has been part of the process of economic development. The potential to emigrate increases with greater per capita income. "Tiger" economies have been labor importers. Safe sex is not practiced in many Asian countries because risk is not taken seriously. Migrants tend to be used as economic tools, without consideration of social adjustment and sex behavior among singles.
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Shorebird Migration Patterns in Response to Climate Change: A Modeling Approach
Smith, James A.
2010-01-01
The availability of satellite remote sensing observations at multiple spatial and temporal scales, coupled with advances in climate modeling and information technologies offer new opportunities for the application of mechanistic models to predict how continental scale bird migration patterns may change in response to environmental change. In earlier studies, we explored the phenotypic plasticity of a migratory population of Pectoral sandpipers by simulating the movement patterns of an ensemble of 10,000 individual birds in response to changes in stopover locations as an indicator of the impacts of wetland loss and inter-annual variability on the fitness of migratory shorebirds. We used an individual based, biophysical migration model, driven by remotely sensed land surface data, climate data, and biological field data. Mean stop-over durations and stop-over frequency with latitude predicted from our model for nominal cases were consistent with results reported in the literature and available field data. In this study, we take advantage of new computing capabilities enabled by recent GP-GPU computing paradigms and commodity hardware (general purchase computing on graphics processing units). Several aspects of our individual based (agent modeling) approach lend themselves well to GP-GPU computing. We have been able to allocate compute-intensive tasks to the graphics processing units, and now simulate ensembles of 400,000 birds at varying spatial resolutions along the central North American flyway. We are incorporating additional, species specific, mechanistic processes to better reflect the processes underlying bird phenotypic plasticity responses to different climate change scenarios in the central U.S.
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INFLUENCE OF LABOUR MIGRATION PROCESSES ON THE QUALITY OF HUMAN CAPITAL OF THE RUSSIAN FEDERATION
Directory of Open Access Journals (Sweden)
Victor M. Volodin
2017-01-01
Full Text Available Abstract. Objectives The aim of the study is to identify the impact of labour migration processes on the quality of human capital. Methods For researching the methods and forms of migration capital’s impact on the formation of a new quality of human capital, a systematic approach is applied. In order to identify the imbalance in the distribution of labour resources among the regions of the Russian Federation and to assess migration processes, analytical and synthetic as well as statistical and comparative methods were applied. In order to help to visualise the identified economic and statistical dependencies, graphic images are provided. Results The essence of migration processes in the era of economic turbulence is revealed. The main share of labour migrants in the overall structure of migratory flows to the Russian Federation are labour migrants from the CIS countries; the main reasons for this situation are established. The factors of Russia’s high migration attractiveness are identified and the basic migratory process management tasks are defined. Among the main tasks of migration process management are: ensuring the national security of the Russian Federation; preservation, maintenance and improvement of comfort, well-being and quality of life of the Russian Federation population; solving the problems of stability and growth of the permanent population of the Russian Federation; creating conditions for the full satisfaction of the high-quality labour resource needs of the Russian economy, attracting labour migrants from highly developed countries; formation of conditions for the transition to sustainable development based on the introduction of scientific and technological progress and the creation of competitive industries. Conclusion The paper suggests three scenarios for the development of migration processes in Russia: inertial, realistic and optimistic. Improvements in the quality of migration capital can be achieved through the
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Directory of Open Access Journals (Sweden)
Douglas W Hamilton
Full Text Available Considered to be the "holy grail" of dentistry, regeneration of the periodontal ligament in humans remains a major clinical problem. Removal of bacterial biofilms is commonly achieved using EDTA gels or lasers. One side effect of these treatment regimens is the etching of nanotopographies on the surface of the tooth. However, the response of periodontal ligament fibroblasts to such features has received very little attention. Using laser interference lithography, we fabricated precisely defined topographies with continuous or discontinuous nanogrooves to assess the adhesion, spreading and migration of PDL fibroblasts. PDL fibroblasts adhered to and spread on all tested surfaces, with initial spreading and focal adhesion formation slower on discontinuous nanogrooves. Cells had a significantly smaller planar area on both continuous and discontinuous nanogrooves in comparison with cells on non-patterned controls. At 24 h post seeding, cells on both types of nanogrooves were highly elongated parallel to the groove long axis. Time-lapse video microscopy revealed that PDL fibroblast movement was guided on both types of grooves, but migration velocity was not significantly different from cells cultured on non-patterned controls. Analysis of filopodia formation using time-lapse video microscopy and labeling of vinculin and F-actin revealed that on nanogrooves, filopodia were highly aligned at both ends of the cell, but with increasing time filopodia and membrane protrusions developed at the side of the cell perpendicular to the cell long axis. We conclude that periodontal ligament fibroblasts are sensitive to nanotopographical depths of 85-100 µm, which could be utilized in regeneration of the periodontal ligament.
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Directory of Open Access Journals (Sweden)
Yuta eMiyazaki
2016-01-01
Full Text Available AbstractThe radial and tangential neural migration pathways are two major neuronal migration streams in humans that are critical during corticogenesis. Corticogenesis is a complex process of neuronal proliferation that is followed by neuronal migration and the formation of axonal connections. Existing histological assessments of these two neuronal migration pathways have limitations inherent to microscopic studies and are confined to small anatomic regions of interest. Thus, little evidence is available about their three-dimensional fiber pathways and development throughout the entire brain. In this study, we imaged and analyzed radial and tangential migration pathways in the whole human brain using high-angular resolution diffusion MR imaging (HARDI tractography. We imaged ten fixed, postmortem fetal (17 gestational weeks (GW, 18 GW, 19 GW, three 20 GW, three 21 GW and 22 GW and eight in vivo newborn (two 30 GW, 34 GW, 35 GW and four 40 GW brains with no neurological/pathological conditions. We statistically compared the volume of the left and right radial and tangential migration pathways, and the volume of the radial migration pathways of the anterior and posterior regions of the brain. In specimens 22 GW or younger, the volume of radial migration pathways of the left hemisphere was significantly larger than that of the right hemisphere. The volume of posterior radial migration pathways was also larger when compared to the anterior pathways in specimens 22 GW or younger. In contrast, no significant differences were observed in the radial migration pathways of brains older than 22 GW. Moreover, our study did not identify any significant differences in volumetric laterality in the tangential migration pathways. These results suggest that these two neuronal migration pathways develop and regress differently, and radial neuronal migration varies regionally based on hemispheric and anterior-posterior laterality, potentially explaining regional
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Directory of Open Access Journals (Sweden)
Jean-Michel Bourget
2016-01-01
Full Text Available Tissue engineering of large organs is currently limited by the lack of potent vascularization in vitro. Tissue-engineered bone grafts can be prevascularized in vitro using endothelial cells (ECs. The microvascular network architecture could be controlled by printing ECs following a specific pattern. Using laser-assisted bioprinting, we investigated the effect of distance between printed cell islets and the influence of coprinted mesenchymal cells on migration. When printed alone, ECs spread out evenly on the collagen hydrogel, regardless of the distance between cell islets. However, when printed in coculture with mesenchymal cells by laser-assisted bioprinting, they remained in the printed area. Therefore, the presence of mesenchymal cell is mandatory in order to create a pattern that will be conserved over time. This work describes an interesting approach to study cell migration that could be reproduced to study the effect of trophic factors.
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Macro patterns of internal migration in Indonesia, 1971-1990.
Alatas, S
1993-12-01
Indonesia's population mobility rate is still relatively low. In 1990 only 8.25% of Indonesians lived outside the provinces where they were born. In contrast, according to the US censuses, since the 1870s no fewer than 20% of Americans did. The level of population mobility is even lower for inter-island and interregional migration. In 1990 only 4.29% of Indonesians lived outside their home islands or regions. The level of urbanization has also had an impact, with rural-urban migration increasing from 17.18% in 1971 to 22.38% in 1980, and to 30.93% in 1990. Between 1971 and 1990 the increase amounted to 20.34% in Jakarta, Surbaya, Bandung, Medan, and Semarang. Migration occurs because people want to improve their lives. The reasons for migration include: 1) to continue education, 2) to search for a better job, 3) to obtain better wages or income, 4) to accompany parents or spouse, 5) to secure political support, and 6) to escape from unpleasant conditions. The 1990 census data on migration were derived from 1) province of birth, 2) province of previous residence, 3) duration of residence at the current province, and 4) province of residence 5 years prior to the census. Interprovincial life time migration increased in Indonesia from 5.8 million in 1971 to 10.2 million in 1980 and to 14.8 million in 1990. Most of the provinces of Sumatra and Kalimantan experienced net positive migration in which in-migration exceeded out-migration. On the other hand, migrants from Jakarta to West Java accounted for 75.6% or 794,987 out of the 1,052,234 people who moved out of the capital city. In 1971 as much as 31.18% of migration across provincial borders headed for DKI Jakarta. In 1990 DKI Jakarta and West Java accommodated 37.75% of the interprovincial migrants. Recent in, out, and net migration declined 2.8 million between 1980 and 1985, but it went up to 5.3 million between 1985 and 1990. Between 1985 and 1990 interprovincial migration towards urban areas amounted to 3.2 million
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Subgenotype A1 of HBV--tracing human migrations in and out of Africa.
Kramvis, Anna; Paraskevis, Dimitrios
2013-01-01
HBV subgenotype A1 is the dominant genotype A strain in Africa, with molecular characteristics differentiating it from A2, which prevails elsewhere. Outside Africa, A1 is confined to areas with migration history from Africa, including India and Latin America. The aim of this study was to reconstruct A1 phylogeny on a spatial scale in order to determine whether A1 can be used to track human migrations. A phylogenetic comparison of A1 was established using neighbour-joining analysis of complete genomes, and the Bayesian method, implemented in BEAST, was performed on the S region of isolates from 22 countries. Migration events were estimated by ancestral state reconstruction using the criterion of parsimony. From the tree reconstruction, nucleotide divergence calculations and migration analysis, it was evident that Africa was the source of dispersal of A1 globally, and its dispersal to Asia and Latin America occurred at a similar time period. Strains from South Africa were the most divergent, clustering in both the African and Asian/American clades and a South African subclade was the origin of A1. The effect of the 9th to 19th century trade and slave routes on the dispersal of A1 was evident and certain unexpected findings, such as the co-clustering of Somalian and Latin American strains, and the dispersal of A1 from India to Haiti, correlated with historical evidence. Phylogeographic analyses of subgenotype A1 can be used to trace human migrations in and out of Africa and the plausible sites of origin and migration routes are presented.
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[Migration of dentists within Hungary].
Balázs, Péter
2010-09-01
Concerning the human resource management in the health care, Hungarian analysts focus mainly on cross-national migration, which was instigated considerably by joining the European Union in 2004. Contrasted to other health care professionals, dentists emphasized also the importance of in-country migration (mobility) indicating serious dangers of developing inequalities in the dental service. From the point of view of health system planning, the main problem is to balance the needs and the number of professionals in regions and areas with extremely different socio-economic conditions. Under dictatorial governments, this "balancing" (which was experienced also in Hungary) is a forced allocation of young professionals to the target regions. In political freedom and free market economy, these measures are unthinkable. The present domestic area distribution, concerning also the supply through vacancies by old age inactivity and cross-national migration, is ruled by personal decisions of actually graduated and immigrant professionals respectively. Therefore, it is unavoidable to investigate the interrelation of factors (dentists' births place, study migration and decisions for practice allocation) ruling the in-country geographic patterns of dental practices. This evidence-based knowledge can only explain the present situation and provide guidelines for health policy decision makers.
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Climate Variability and Human Migration in the Netherlands, 1865–1937
Jennings, Julia A.; Gray, Clark L.
2014-01-01
Human migration is frequently cited as a potential social outcome of climate change and variability, and these effects are often assumed to be stronger in the past when economies were less developed and markets more localized. Yet, few studies have used historical data to test the relationship between climate and migration directly. In addition, the results of recent studies that link demographic and climate data are not consistent with conventional narratives of displacement responses. Using longitudinal individual-level demographic data from the Historical Sample of the Netherlands (HSN) and climate data that cover the same period, we examine the effects of climate variability on migration using event history models. Only internal moves in the later period and for certain social groups are associated with negative climate conditions, and the strength and direction of the observed effects change over time. International moves decrease with extreme rainfall, suggesting that the complex relationships between climate and migration that have been observed for contemporary populations extend into the nineteenth century. PMID:25937689
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Sanderson, Matthew
2010-01-01
Contemporary levels of international migration in less-developed countries are raising new and important questions regarding the consequences of immigration for human welfare and well-being. However, there is little systematic cross-national evidence of how international migration affects human development levels in migrant-receiving countries in…
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Population specific migration patterns of an European-Afrotropical songbird
DEFF Research Database (Denmark)
Pedersen, Lykke; Tøttrup, Anders P.; Thorup, Kasper
Every year, billions of songbirds migrate thousands of kilometres between the European and African continent. The fascinating behaviour of migration that we are witnessing today is assumed to have evolved through a series of dispersal events from Africa into Europe since the last glaciation period....... Recent technological advances are currently enabling us to track yet smaller songbirds throughout their migration cycle providing valuable insight into the life cycle of individual birds. However, direct tracking of migratory birds has so far mainly been conducted on single populations and our...... understanding of entire species migration systems is thus still limited. In this project we analyse the spatio-temporal migration schedule of Red-backed Shrikes, Lanius collurio, using tracking data from individuals originating from geographically distinct breeding populations (Scandinavia, the Netherlands...
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Solberg, Ingrid
2016-11-27
We addressed the behavioral patterns and DVM dynamics of sprat overwintering in a 150 m Norwegian fjord with increasing hypoxia by depth. An upward-facing echosounder deployed at the bottom and cabled to shore provided 4 months of continuous acoustic data. This enabled detailed studies of individual behavior, specifically allowing assessment of individual vertical migrations at dusk and dawn in relation to light, analysis of so-called rise-and-sink swimming, and investigation of the sprat’ swimming activity and behavior in severely hypoxic waters. Field campaigns supplemented the acoustic studies. The acoustic records showed that the main habitat for sprat was the upper ∼ 65 m where oxygen concentrations were ⩾ 0.7 mL O2 L-1. The sprat schooled at ∼ 50 m during daytime and initiated an upward migration about 1 hour prior to sunset. While some sprat migrated to surface waters, other individuals interrupted the ascent when at ∼20-30 m, and returned to deeper waters ∼ 20-50 min after sunset. Sprat at depth was on average larger, yet individuals made excursions to- and from upper layers. Sprat were swimming in a “rise and sink” pattern at depth, likely related to negative buoyancy. Short-term dives into waters with less than 0.45 mL O2 L-1 were interpreted as feeding forays for abundant overwintering Calanus spp. The deep group of sprat initiated a dawn ascent less than 1 hour before sunrise, ending at 20-30 m where they formed schools. They subsequently returned to deeper waters about ∼20 min prior to sunrise. Measurements of surface light intensities indicated that the sprat experienced lower light levels in upper waters at dawn than at dusk. The vertical swimming speed varied significantly between the behavioral tasks. The mixed DVM patterns and dynamic nocturnal behavior of sprat persisted throughout winter, likely shaped by individual strategies involving optimized feeding and predator avoidance, as well as relating to temperature, hypoxia and
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Antezana, Tarsicio
2009-12-01
A series of stratified bongo net samples taken over a 2 day period at ca. 18°S, about 20 nm off the coast of Peru, South America, suggest species-specific patterns of diel vertical migration into the Oxygen Minimum Zone (OMZ) of the Humboldt Current Ecosystem (HCE). The OMZ was the most dramatic feature of the water column and seemed to determine the extent of migration: Stylocheiron affine migrated only to the shallow oxycline; whereas Euphausia mucronata, Euphausia eximia, Euphausia distinguenda and Euphausia tenera migrated to the core of the OMZ; and Nematoscelis gracilis to beneath the core of the OMZ. Some differences were also found in the timing and duration of the ascent and descent, and residence times in shallow and deep layers. E. mucronata, N. gracilis and E. distinguenda displayed a normal descent during sunrise, and ascent during sunset. E. eximia and E. tenera also descended during sunrise but seemed to begin their ascent earlier in the afternoon and consequently shortened their deep residence times. S. affine showed the most extended residence times at the shallow layer and the shortest vertical displacement. Day and night vertical stratification and differences in the timing of migration into and out of the OMZ of the HCE suggest a community structure based on habitat partitioning whereby species avoided co-occurrence in time and space. Species-specific patterns of vertical stratification and migratory chronology are examined with regard to body and gill sizes, feeding adaptations of euphausiids, and potential food resources at the OMZ.
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Silk Film Topography Directs Collective Epithelial Cell Migration
Rosenblatt, Mark I.
2012-01-01
The following study provides new insight into how surface topography dictates directed collective epithelial cell sheet growth through the guidance of individual cell movement. Collective cell behavior of migrating human corneal limbal-epithelial cell sheets were studied on highly biocompatible flat and micro-patterned silk film surfaces. The silk film edge topography guided the migratory direction of individual cells making up the collective epithelial sheet, which resulted in a 75% increase in total culture elongation. This was due to a 3-fold decrease in cell sheet migration rate efficiency for movement perpendicular to the topography edge. Individual cell migration direction is preferred in the parallel approach to the edge topography where localization of cytoskeletal proteins to the topography’s edge region is reduced, which results in the directed growth of the collective epithelial sheet. Findings indicate customized biomaterial surfaces may be created to direct both the migration rate and direction of tissue epithelialization. PMID:23185573
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Migration in Tanzania: Patterns, Characteristics and Impact | Moshi ...
African Journals Online (AJOL)
but more so on the socio-economic impact of migration. On the economic consequences of migration a lot of emphasis has been placed on remittances. This is understandable for two main reasons. One, remittances have emerged as a major source of external development finance in recent years. Given their large size, ...
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Sun, Mingming; Ye, Mao; Schwab, Arthur P; Li, Xu; Wan, Jinzhong; Wei, Zhong; Wu, Jun; Friman, Ville-Petri; Liu, Kuan; Tian, Da; Liu, Manqiang; Li, Huixin; Hu, Feng; Jiang, Xin
2016-09-05
Landfills are perfect sites to study the effect of human migration on fluctuation of antibiotic resistance genes (ARGs) as they are the final destination of municipal waste. For example, large-scale human migration during the holidays is often accompanied by changes in waste dumping having potential effects on ARG abundance. Three landfills were selected to examine fluctuation in the abundance of fifteen ARGs and Intl1 genes for 14 months in Nanjing, eastern China. Mass human migration, the amount of dumped waste and temperature exerted the most significant effects on bimonthly fluctuations of ARG levels in landfill sites. As a middle-sized cosmopolitan city in China, millions of college students and workers migrate during holidays, contributing to the dramatic increases in waste production and fluctuation in ARG abundances. In line with this, mass migration explained most of the variation in waste dumping. The waste dumping also affected the bioaccessibility of mixed-compound pollutants that further positively impacted the level of ARGs. The influence of various bioaccessible compounds on ARG abundance followed the order: antibiotics>nutrients>metals>organic pollutants. Concentrations of bioaccessible compounds were more strongly correlated with ARG levels compared to total compound concentrations. Improved waste classification and management strategies could thus help to decrease the amount of bioaccessible pollutants leading to more effective control for urban ARG dissemination. Copyright © 2016 Elsevier B.V. All rights reserved.
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Circular migration patterns and determinants in Nairobi slum settlements
Directory of Open Access Journals (Sweden)
Donatien Beguy
2010-09-01
Full Text Available This paper measures migration flows and determinants in two slum settlements in Nairobi City between 2003 and 2007. The results confirm the high intensity of migration with a quarter of the total slum population and a third of those aged 15-30 being renewed annually. A circular migration system is at play whereby the majority of slum dwellers are short-term migrants spending on average less than 3 years in the area. Migration is more intense during early adulthood (20-24, and despite very similar determinants across gender, mobility is more intense among women compared to men. The increasing feminization of migration is likely to change the face of slum settlements, resulting in more balanced sex ratios, in line with city-wide trends in Nairobi over the past half century. The high population turnover is due to the insecurity of livelihoods, tenure, and poor basic amenities and social services in slum settlements.
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International Nuclear Information System (INIS)
Shi, Guo-Zhen; Yuan, Yang; Jiang, Guo-Jun; Ge, Zhi-Jun; Zhou, Jian; Gong, De-Jun; Tao, Jing; Tan, Yong-Fei; Huang, Sheng-Dong
2012-01-01
Prenylated Rab acceptor 1 domain family member 3 (PRAF3) is involved in the regulation of many cellular processes including apoptosis, migration and invasion. This study was conducted to investigate the effect of PRAF3 on apoptosis, migration and invasion in human esophageal squamous cell carcinoma (ESCC). The expression of PRAF3 mRNA and protein in primary ESCC and the matched normal tissues (57cases) was determined by quantitative RT-PCR and Western blot. Immunohistochemical analysis of PRAF3 expression was carried out in paraffin-embedded sections of ESCC and correlated with clinical features. The role of PRAF3 in apoptosis, migration and invasion was studied in ESCC cell lines of Eca109 and TE-1 through the adenovirus mediated PRAF3 gene transfer. The effect of PRAF3 on apoptosis was analyzed by annexin V-FITC assay. The regulation of PRAF3 on migration was determined by transwell and wounding healing assay, while the cellular invasion was analyzed by matrigel-coated transwell assay. We found that the expression of PRAF3 was significantly down-regulated in ESCC tissue compared with the matched normal tissue and was correlated with the clinical features of pathological grade, tumor stage and lymph node metastasis. Moreover, overexpression of PRAF3 induced cell apoptosis through both caspase-8 and caspase-9 dependent pathways, and inhibited cell migration and invasion by suppressing the activity of both MMP-2 and MMP-9 in human ESCC cell lines. Our data suggest that PRAF3 plays an important role in the regulation of tumor progression and metastasis and serves as a tumor suppressor in human ESCC. We propose that PRAF3 might be used as a potential therapeutic agent for human ESCC
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The workforce for health in a globalized context--global shortages and international migration.
Aluttis, Christoph; Bishaw, Tewabech; Frank, Martina W
2014-01-01
The 'crisis in human resources' in the health sector has been described as one of the most pressing global health issues of our time. The World Health Organization (WHO) estimates that the world faces a global shortage of almost 4.3 million doctors, midwives, nurses, and other healthcare professionals. A global undersupply of these threatens the quality and sustainability of health systems worldwide. This undersupply is concurrent with globalization and the resulting liberalization of markets, which allow health workers to offer their services in countries other than those of their origin. The opportunities of health workers to seek employment abroad has led to a complex migration pattern, characterized by a flow of health professionals from low- to high-income countries. This global migration pattern has sparked a broad international debate about the consequences for health systems worldwide, including questions about sustainability, justice, and global social accountabilities. This article provides a review of this phenomenon and gives an overview of the current scope of health workforce migration patterns. It further focuses on the scientific discourse regarding health workforce migration and its effects on both high- and low-income countries in an interdependent world. The article also reviews the internal and external factors that fuel health worker migration and illustrates how health workforce migration is a classic global health issue of our time. Accordingly, it elaborates on the international community's approach to solving the workforce crisis, focusing in particular on the WHO Code of Practice, established in 2010.
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Afolayan, A A
1985-09-01
"The paper sets out to test whether or not the movement pattern of people in Nigeria is step-wise. It examines the spatial order in the country and the movement pattern of people. It then analyzes the survey data and tests for the validity of step-wise migration in the country. The findings show that step-wise migration cannot adequately describe all the patterns observed." The presence of large-scale circulatory migration between rural and urban areas is noted. Ways to decrease the pressure on Lagos by developing intermediate urban areas are considered. excerpt
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Goodman, Joyce; Jacobs, Andrea; Kisby, Fiona; Loader, Helen
2011-01-01
This paper explores the migration patterns of women who studied at Girton and Newnham prior to 1939 through whom dissemination of knowledge and values flowed from Cambridge overseas. It also considers organisations that fostered women's mobility in empire, particularly the Colonial Intelligence League for Educated Women and the International…
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Differential migration and proliferation of geometrical ensembles of cell clusters
International Nuclear Information System (INIS)
Kumar, Girish; Chen, Bo; Co, Carlos C.; Ho, Chia-Chi
2011-01-01
Differential cell migration and growth drives the organization of specific tissue forms and plays a critical role in embryonic development, tissue morphogenesis, and tumor invasion. Localized gradients of soluble factors and extracellular matrix have been shown to modulate cell migration and proliferation. Here we show that in addition to these factors, initial tissue geometry can feedback to generate differential proliferation, cell polarity, and migration patterns. We apply layer by layer polyelectrolyte assembly to confine multicellular organization and subsequently release cells to demonstrate the spatial patterns of cell migration and growth. The cell shapes, spreading areas, and cell-cell contacts are influenced strongly by the confining geometry. Cells within geometric ensembles are morphologically polarized. Symmetry breaking was observed for cells on the circular pattern and cells migrate toward the corners and in the direction parallel to the longest dimension of the geometric shapes. This migration pattern is disrupted when actomyosin based tension was inhibited. Cells near the edge or corner of geometric shapes proliferate while cells within do not. Regions of higher rate of cell migration corresponded to regions of concentrated growth. These findings demonstrate that multicellular organization can result in spatial patterns of migration and proliferation.
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Directory of Open Access Journals (Sweden)
Asako Itakura
Full Text Available Neutrophils serve as a first line of defense in innate immunity owing in part to their ability to rapidly migrate towards chemotactic factors derived from invading pathogens. As a migratory function, neutrophil chemotaxis is regulated by the Rho family of small GTPases. However, the mechanisms by which Rho GTPases orchestrate cytoskeletal dynamics in migrating neutrophils remain ill-defined. In this study, we characterized the role of p21-activated kinase (PAK downstream of Rho GTPases in cytoskeletal remodeling and chemotactic processes of human neutrophils. We found that PAK activation occurred upon stimulation of neutrophils with f-Met-Leu-Phe (fMLP, and PAK accumulated at the actin-rich leading edge of stimulated neutrophils, suggesting a role for PAK in Rac-dependent actin remodeling. Treatment with the pharmacological PAK inhibitor, PF3758309, abrogated the integrity of RhoA-mediated actomyosin contractility and surface adhesion. Moreover, inhibition of PAK activity impaired neutrophil morphological polarization and directional migration under a gradient of fMLP, and was associated with dysregulated Ca(2+ signaling. These results suggest that PAK serves as an important effector of Rho-family GTPases in neutrophil cytoskeletal reorganization, and plays a key role in driving efficient directional migration of human neutrophils.
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Evolution of cooperation driven by social-welfare-based migration
Li, Yan; Ye, Hang; Zhang, Hong
2016-03-01
Individuals' migration behavior may play a significant role in the evolution of cooperation. In reality, individuals' migration behavior may depend on their perceptions of social welfare. To study the relationship between social-welfare-based migration and the evolution of cooperation, we consider an evolutionary prisoner's dilemma game (PDG) in which an individual's migration depends on social welfare but not on the individual's own payoff. By introducing three important social welfare functions (SWFs) that are commonly studied in social science, we find that social-welfare-based migration can promote cooperation under a wide range of parameter values. In addition, these three SWFs have different effects on cooperation, especially through the different spatial patterns formed by migration. Because the relative efficiency of the three SWFs will change if the parameter values are changed, we cannot determine which SWF is optimal for supporting cooperation. We also show that memory capacity, which is needed to evaluate individual welfare, may affect cooperation levels in opposite directions under different SWFs. Our work should be helpful for understanding the evolution of human cooperation and bridging the chasm between studies of social preferences and studies of social cooperation.
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Effects of SOX2 on Proliferation, Migration and Adhesion of Human Dental Pulp Stem Cells.
Directory of Open Access Journals (Sweden)
Pengfei Liu
Full Text Available As a key factor for cell pluripotent and self-renewing phenotypes, SOX2 has attracted scientists' attention gradually in recent years. However, its exact effects in dental pulp stem cells (DPSCs are still unclear. In this study, we mainly investigated whether SOX2 could affect some biological functions of DPSCs. DPSCs were isolated from the dental pulp of human impacted third molar. SOX2 overexpressing DPSCs (DPSCs-SOX2 were established through retroviral infection. The effect of SOX2 on cell proliferation, migration and adhesion ability was evaluated with CCK-8, trans-well system and fibronectin-induced cell attachment experiment respectively. Whole genome expression of DPSCs-SOX2 was analyzed with RNA microarray. Furthermore, a rescue experiment was performed with SOX2-siRNA in DPSC-SOX2 to confirm the effect of SOX2 overexpression in DPSCs. We found that SOX2 overexpression could result in the enhancement of cell proliferation, migration, and adhesion in DPSCs obviously. RNA microarray analysis indicated that some key genes in the signal pathways associated with cell cycle, migration and adhesion were upregulated in different degree, and the results were further confirmed with qPCR and western-blot. Finally, DPSC-SOX2 transfected with SOX2-siRNA showed a decrease of cell proliferation, migration and adhesion ability, which further confirmed the biological effect of SOX2 in human DPSCs. This study indicated that SOX2 could improve the cell proliferation, migration and adhesion ability of DPSCs through regulating gene expression about cell cycle, migration and adhesion, and provided a novel strategy to develop seed cells with strong proliferation, migration and adhesion ability for tissue engineering.
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Effects of SOX2 on Proliferation, Migration and Adhesion of Human Dental Pulp Stem Cells.
Liu, Pengfei; Cai, Jinglei; Dong, Delu; Chen, Yaoyu; Liu, Xiaobo; Wang, Yi; Zhou, Yulai
2015-01-01
As a key factor for cell pluripotent and self-renewing phenotypes, SOX2 has attracted scientists' attention gradually in recent years. However, its exact effects in dental pulp stem cells (DPSCs) are still unclear. In this study, we mainly investigated whether SOX2 could affect some biological functions of DPSCs. DPSCs were isolated from the dental pulp of human impacted third molar. SOX2 overexpressing DPSCs (DPSCs-SOX2) were established through retroviral infection. The effect of SOX2 on cell proliferation, migration and adhesion ability was evaluated with CCK-8, trans-well system and fibronectin-induced cell attachment experiment respectively. Whole genome expression of DPSCs-SOX2 was analyzed with RNA microarray. Furthermore, a rescue experiment was performed with SOX2-siRNA in DPSC-SOX2 to confirm the effect of SOX2 overexpression in DPSCs. We found that SOX2 overexpression could result in the enhancement of cell proliferation, migration, and adhesion in DPSCs obviously. RNA microarray analysis indicated that some key genes in the signal pathways associated with cell cycle, migration and adhesion were upregulated in different degree, and the results were further confirmed with qPCR and western-blot. Finally, DPSC-SOX2 transfected with SOX2-siRNA showed a decrease of cell proliferation, migration and adhesion ability, which further confirmed the biological effect of SOX2 in human DPSCs. This study indicated that SOX2 could improve the cell proliferation, migration and adhesion ability of DPSCs through regulating gene expression about cell cycle, migration and adhesion, and provided a novel strategy to develop seed cells with strong proliferation, migration and adhesion ability for tissue engineering.
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International Nuclear Information System (INIS)
Li, Fang-qiu; Han, Yan-ling; Liu, Qun; Wu, Bo; Huang, Wen-bin; Zeng, Su-yun
2009-01-01
Most deaths from ovarian cancer are due to metastases that are resistant to conventional therapies. But the factors that regulate the metastatic process and chemoresistance of ovarian cancer are poorly understood. In the current study, we investigated the aberrant expression of human sperm protein 17 (HSp17) in human epithelial ovarian cancer cells and tried to analyze its influences on the cell behaviors like migration and chemoresistance. Immunohistochemistry and immunocytochemistry were used to identify HSp17 in paraffin embedded ovarian malignant tumor specimens and peritoneal metastatic malignant cells. Then we examined the effect of HSp17 overexpression on the proliferation, migration, and chemoresistance of ovarian cancer cells to carboplatin and cisplatin in a human ovarian carcinoma cell line, HO8910. We found that HSp17 was aberrantly expressed in 43% (30/70) of the patients with primary epithelial ovarian carcinomas, and in all of the metastatic cancer cells of ascites from 8 patients. The Sp17 expression was also detected in the metastatic lesions the same as in ovarian lesions. None of the 7 non-epithelial tumors primarily developed in the ovaries was immunopositive for HSp17. Overexpression of HSp17 increased the migration but decreased the chemosensitivity of ovarian carcinoma cells to carboplatin and cisplatin. HSp17 is aberrantly expressed in a significant proportion of epithelial ovarian carcinomas. Our results strongly suggest that HSp17 plays a role in metastatic disease and resistance of epithelial ovarian carcinoma to chemotherapy
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Directory of Open Access Journals (Sweden)
Schwarz, C.
2004-06-01
Full Text Available Ringing of birds unveiled many aspects of avian migration and dispersal movements. However, there is even much more to be explored by the use of ringing and other marks. Dispersal is crucial in understanding the initial phase of migration in migrating birds as it is to understand patterns and processes of distribution and gene flow. So far, the analysis of migration was largely based on analysing spatial and temporal patters of recoveries of ringed birds. However, there are considerable biases and pitfalls in using recoveries due to spatial and temporal variation in reporting probabilities. Novel methods are required for future studies separating the confounding effects of spatial and temporal heterogeneity of recovery data and heterogeneity of the landscape as well. These novel approaches should aim a more intensive and novel use of the existing recovery data by taking advantage of, for instance, dynamic and multistate modeling, should elaborate schemes for future studies, and should also include other marks that allow a more rapid data collection, like telemetry, geolocation and global positioning systems, and chemical and molecular markers. The latter appear to be very useful in the delineating origin of birds and connectivity between breeding and non–breeding grounds. Many studies of migration are purely descriptive. However, King and Brooks (King & Brooks, 2004 examine if movement patterns of dolphins change after the introduction of a gillnet ban. Bayesian methods are an interesting approach to this problem as they provide a meaningful measure of the probability that such a change occurred rather than simple yes/no response that is often the result of classical statistical methods. However, the key difficulty of a general implementation of Bayesian methods is the complexity of the modelling —there is no general userfriendly package that is easily accessible to most scientists. Drake and Alisauskas (Drake & Alisauskas, 2004 examine the
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Kinoshita, Yusuke; Kamitani, Hideki; Mamun, Mahabub Hasan; Wasita, Brian; Kazuki, Yasuhiro; Hiratsuka, Masaharu; Oshimura, Mitsuo; Watanabe, Takashi
2010-05-01
Mesenchymal stem cells (MSCs) have been expected to become useful gene delivery vehicles against human malignant gliomas when coupled with an appropriate vector system, because they migrate towards the lesion. Human artificial chromosomes (HACs) are non-integrating vectors with several advantages for gene therapy, namely, no limitations on the size and number of genes that can be inserted. We investigated the migration of human immortalized MSCs bearing a HAC vector containing the herpes simplex virus thymidine kinase gene (HAC-tk-hiMSCs) towards malignant gliomas in vivo. Red fluorescence protein-labeled human glioblastoma HTB14 cells were implanted into a subcortical region in nude mice. Four days later, green fluorescence protein-labeled HAC-tk-hiMSCs were injected into a contralateral subcortical region (the HTB14/HAC-tk-hiMSC injection model). Tropism to the glioma mass and the route of migration were visualized by fluorescence microscopy and immunohistochemical staining. HAC-tk-hiMSCs began to migrate toward the HTB14 glioma area via the corpus callosum on day 4, and gathered around the HTB14 glioma mass on day 7. To test whether the delivered gene could effectively treat glioblastoma in vivo, HTB14/HAC-tk-hiMSC injected mice were treated with ganciclovir (GCV) or PBS. The HTB14 glioma mass was significantly reduced by GCV treatment in mice injected with HAC-tk-hiMSCs. It was confirmed that gene delivery by our HAC-hiMSC system was effective after migration of MSCs to the glioma mass in vivo. Therefore, MSCs containing HACs carrying an anticancer gene or genes may provide a new tool for the treatment of malignant gliomas and possibly of other tumor types.
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Hsu, Hsi-Hsien; Kuo, Wei-Wen; Ju, Da-Tong; Yeh, Yu-Lan; Tu, Chuan-Chou; Tsai, Ying-Lan; Shen, Chia-Yao; Chang, Sheng-Huang; Chung, Li-Chin; Huang, Chih-Yang
2014-11-28
To investigate the effects of 17β-estradiol via estrogen receptors (ER) or direct administration of ER agonists on human colorectal cancer. LoVo cells were established from the Bioresource Collection and Research Center and cultured in phenol red-free DMEM (Sigma, United States). To investigate the effects of E2 and/or ER selective agonists on cellular proliferation, LoVo colorectal cells were treated with E2 or ER-selective agonists for 24 h and 48 h and subjected to the MTT (Sigma) assay to find the concentration. And investigate the effects of E2 and/or ER selective agonists on cell used western immunoblotting to find out the diversification of signaling pathways. In order to observe motility and migration the wound healing assay and a transwell chamber (Neuro Probe) plate were tased. For a quantitative measure, we counted the number of migrating cells to the wound area post-wounding for 24 h. We further examined the cellular migration-regulating factors urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and matrix metalloproteinase (MMP)-9 in human LoVo cells so gelatin zymography that we used and gelatinolytic activity was visualized by Coomassie blue staining. And these results are presented as means ± SE, and statistical comparisons were made using Student's t-test. The structure was first compared with E2 and ER agonists. We then treated the LoVo cells with E2 and ER agonists (10(-8) mol/L) for 24 h and 48 h and subsequently measured the cell viability using MTT assay. Our results showed that treatment with 17β-estradiol and/or ER agonists in human LoVo colorectal cancer cells activated p53 and then up-regulated p21 and p27 protein levels, subsequently inhibiting the downstream target gene, cyclin D1, which regulates cell proliferation. Taken together, our findings demonstrate the anti-tumorigenesis effects of 17β-estradiol and/or ER agonists and suggest that these compounds may prove to be a potential alternative
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Baicalein inhibits the migration and invasive properties of human hepatoma cells
International Nuclear Information System (INIS)
Chiu, Yung-Wei; Lin, Tseng-Hsi; Huang, Wen-Shih; Teng, Chun-Yuh; Liou, Yi-Sheng; Kuo, Wu-Hsien; Lin, Wea-Lung; Huang, Hai-I; Tung, Jai-Nien; Huang, Chih-Yang; Liu, Jer-Yuh; Wang, Wen-Hung; Hwang, Jin-Ming
2011-01-01
Flavonoids have been demonstrated to exert health benefits in humans. We investigated whether the flavonoid baicalein would inhibit the adhesion, migration, invasion, and growth of human hepatoma cell lines, and we also investigated its mechanism of action. The separate effects of baicalein and baicalin on the viability of HA22T/VGH and SK-Hep1 cells were investigated for 24 h. To evaluate their invasive properties, cells were incubated on matrigel-coated transwell membranes in the presence or absence of baicalein. We examined the effect of baicalein on the adhesion of cells, on the activation of matrix metalloproteinases (MMPs), protein kinase C (PKC), and p38 mitogen-activated protein kinase (MAPK), and on tumor growth in vivo. We observed that baicalein suppresses hepatoma cell growth by 55%, baicalein-treated cells showed lower levels of migration than untreated cells, and cell invasion was significantly reduced to 28%. Incubation of hepatoma cells with baicalein also significantly inhibited cell adhesion to matrigel, collagen I, and gelatin-coated substrate. Baicalein also decreased the gelatinolytic activities of the matrix metalloproteinases MMP-2, MMP-9, and uPA, decreased p50 and p65 nuclear translocation, and decreased phosphorylated I-kappa-B (IKB)-β. In addition, baicalein reduced the phosphorylation levels of PKCα and p38 proteins, which regulate invasion in poorly differentiated hepatoma cells. Finally, when SK-Hep1 cells were grown as xenografts in nude mice, intraperitoneal (i.p.) injection of baicalein induced a significant dose-dependent decrease in tumor growth. These results demonstrate the anticancer properties of baicalein, which include the inhibition of adhesion, invasion, migration, and proliferation of human hepatoma cells in vivo. - Highlight: → Baicalein inhibits several essential steps in the onset of metastasis.
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del Pliego, Margarita González; Aguirre-Benítez, Elsa; Paisano-Cerón, Karina; Valdovinos-Ramírez, Irene; Rangel-Morales, Carlos; Rodríguez-Mata, Verónica; Solano-Agama, Carmen; Martín-Tapia, Dolores; de la Vega, María Teresa; Saldoval-Balanzario, Miguel; Camacho, Javier; Mendoza-Garrido, María Eugenia
2013-01-01
Pituitary adenomas can invade surrounded tissue, but the mechanism remains elusive. Ether à go-go-1 (Eag1) potassium channel and epidermal growth factor receptors (ErbB1 and ErbB2) have been associated to invasive phenotypes or poor prognosis in cancer patients. However, cells arrange their cytoskeleton in order to acquire a successful migration pattern. We have studied ErbBs and Eag1 expression, and cytoskeleton arrangements in 11 human pituitary adenomas. Eag1, ErbB1 and ErbB2 expression were studied by immunochemistry in tissue and cultured cells. The cytoskeleton arrangement was analyzed in cultured cells by immunofluorescence. Normal pituitary tissue showed ErbB2 expression and Eag1 only in few cells. However, Eag1 and ErbB2 were expressed in all the tumors analyzed. ErbB1 expression was observed variable and did not show specificity for a tumor characteristic. Cultured cells from micro- and macro-adenomas clinically functional organize their cytoskeleton suggesting a mesenchymal pattern, and a round leucocyte/amoeboid pattern from invasive clinically silent adenoma. Pituitary tumors over-express EGF receptors and the ErbB2 repeated expression suggests is a characteristic of adenomas. Eag 1 was express, in different extent, and could be a therapeutic target. The cytoskeleton arrangements observed suggest that pituitary tumor cells acquire different patterns: mesenchymal, and leucocyte/amoeboid, the last observed in the invasive adenomas. Amoeboid migration pattern has been associated with high invasion capacity.
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The human right to migration and emerging intercultural citizenships
Vior, Eduardo J.; Bonilla, Alcira B.
2012-01-01
Despite its widespread application, the human right to migration proclaimed by Law No. 25.871 (2004) poses a legitimacy problem for the Argentinian state, since it means the state has recognized that people’s right to settle wherever they like is superior to the State’s right to regulate entry. In addition, the birth of a second, citizen generation leads immigrant communities to exercise their political powers. The experience from 19th century shows however how the States and social majoritie...
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Migration of acute lymphoblastic leukemia cells into human bone marrow stroma.
Makrynikola, V; Bianchi, A; Bradstock, K; Gottlieb, D; Hewson, J
1994-10-01
Most cases of acute lymphoblastic leukemia (ALL) arise from malignant transformation of B-cell precursors in the bone marrow. Recent studies have shown that normal and leukemic B-cell precursors bind to bone marrow stromal cells through the beta-1 integrins VLA-4 and VLA-5, thereby exposing early lymphoid cells to regulatory cytokines. It has been recently reported that the pre-B cell line NALM-6 is capable of migrating under layers of murine stromal cells in vitro (Miyake et al. J Cell Biol 1992;119:653-662). We have further analyzed leukemic cell motility using human bone marrow fibroblasts (BMF) as a stromal layer. The precursor-B ALL cell line NALM-6 rapidly adhered to BMF, and underwent migration or tunneling into BMF layers within 5 h, as demonstrated by light and electron microscopy, and confirmed by a chromium-labeling assay. Migration was also observed with the precursor-B ALL lines Reh and KM-3, with a T leukemia line RPMI-8402, the monocytic line U937, and the mature B line Daudi. In contrast, mature B (Raji), myeloid (K562, HL-60), and T lines (CCRF-CEM, MOLT-4) did not migrate. When cases of leukemia were analyzed, BMF migration was largely confined to precursor-B ALL, occurring in eight of 13 cases tested. Of other types of leukemia, migration was observed in one of four cases of T-ALL, but no evidence was seen in six acute myeloid leukemias and two patients with chronic lymphocytic leukemia. Only minimal migration into BMF was observed with purified sorted CD10+ CD19+ early B cells from normal adult marrow, while normal mature B lymphocytes from peripheral blood did not migrate. ALL migration was inhibited by monoclonal antibodies to the beta sub-unit of the VLA integrin family, and by a combination of antibodies to VLA-4 and VLA-5. Partial inhibition was also observed when leukemic cells were incubated with antibodies to VLA-4, VLA-5, or VLA-6 alone. In contrast, treatment of stromal cells with antibodies to vascular cell adhesion molecule or
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Directory of Open Access Journals (Sweden)
Yolanda H. Chen
2016-05-01
Full Text Available Abstract Ecological pest management seeks to improve pest control through the manipulation of ecological processes that promote natural enemies and suppress pests. These approaches can involve cultural practices such as reduced tillage, increased use of non-crop plants that provide food and shelter for natural enemies, and intercropping to enhance the abundance and diversity of natural enemies. A major assumption of ecological pest management is that these activities can be equally effective for all insect herbivores. Here, I propose that these strategies may only be effective for a subset of pests and geographic regions because most insect pests have complex evolutionary histories that make them difficult to manage. I discuss how crop domestication and human-mediated migration are major evolutionary events that shape the geography of interactions between plants, herbivores, and natural enemies. Insect herbivores can evolve to be pests through three major modes: 1 herbivores associated with the crop wild ancestor may shift onto the domesticated crop, 2 herbivores may host-shift from native host plants onto an introduced crop, or 3 human-mediated migration can introduce insect pests into new cropping regions. The resulting geographic structure can influence the success of pest management by altering ecological factors such as: species distributions, patterns of biodiversity, community structure, and natural enemy attack rates. I discuss how the different modes of insect pest evolution structure a set of relevant questions and approaches for ecological pest management. By acknowledging how agricultural history and geography shape the ecology and evolution of insect pests, we may collectively develop a better capacity to identify where and how ecological pest management approaches can be most broadly effective.
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The Human Central Pattern Generator for Locomotion.
Minassian, Karen; Hofstoetter, Ursula S; Dzeladini, Florin; Guertin, Pierre A; Ijspeert, Auke
2017-03-01
The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion. In the absence of volitional motor control and step-specific sensory feedback, the human lumbar spinal cord can produce rhythmic muscle activation patterns that closely resemble CPG-induced neural activity of the isolated animal spinal cord. In this sense, CPGs in humans can be defined by the activity they produce. During normal locomotion, CPGs could contribute to the activation patterns during specific phases of the step cycle and simplify supraspinal control of step cycle frequency as a feedforward component to achieve a targeted speed. Determining how the human CPGs operate will be essential to advance the theory of neural control of locomotion and develop new locomotor neurorehabilitation paradigms.
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Chattopadhyay, Kausik; Chattopadhyay, Pallavi
2017-04-01
Uttarakhand, a Himalayan state of India is facing a worst scenario of rural population migration for the past few decades from hill regions to the planes. While urbanization is believed to be one of the major factors for migration, how geo scientific parameters can impact the population to redraw the demographies of the hills is studied in this research. An attempt is made using density based clustering and Apriori association rule mining on 45 derived variables with a time series of 30 years to understand the rural population migration pattern. Both zone identification and origin-destination pair extraction are formulated as spatial-temporal point clustering problem and DBSCAN (Density-Based Spatial Clustering of Applications with Noise) is applied to solve them. Specifically the population migration is formulated as a 4D point clustering problem and the relative distance between two origin - destination pair with a preference factor is used to fine tune the cluster length. In Apriori, threshold values for confidence and J-measure are kept same as for rule extraction. Rules with maximum confidence level and J-measure are obtained for an antecedent window of 18 months, consequent window of 4 months and time lag of 2 months. From the rules extracted, it can be demonstrated that almost all the geoscience indices are occurring as antecedents for migration episodes. The result demonstrates that the three districts that have registered the highest migration rates are also the districts that have witnessed maximum depletion in water sources. Even though some districts have higher number of landslide incidents, their out migration is less compared to other hill districts. However districts experiencing higher number of earthquakes are experiencing higher out migration. Upper hill region with higher precipitation experience higher migration compared to their lower hill counterpart. However this is not true when compared to the counter parts in the plane regions. Even
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International Elderly Migration in Hungary
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Sándor Illés
2006-06-01
Full Text Available The paper examines international elderly migration (IEM related to Hungary. Little effort has been made to investigate this increasingly important element of human migration in Central and Eastern Europe. The general objective of this study is to contribute to filling this gap. IEM is investigated using register-based data on migration flows, stocks and citizenship statistics. The analysis focuses on the time series but the paper also considers the historical context and the recent patterns of IEM. The aim of the research was fourfold. Firstly, we tried to establish when IEM related to Hungary began. Secondly, we detected the accelerating character of this phenomenon. Thirdly, we were able to identify the main macrofactors influencing the level of IEM. Fourthly, the main result of the study was that it allowed exploration of a Hungarian peculiarity. “Pension seeking” is one very distinctive feature of IEM and is in many ways a legacy of the state socialism period. Therefore, its emergence on such a large scale is the result of the transformation period. We suppose that pension-hunting type migration will be temporary in nature. Conclusions about the motivational structure of IEM are discussed with reference to policy implications in the light of the ageing population structure in Hungary.
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Beyond the average: Diverse individual migration patterns in a population of mesopelagic jellyfish
Kaartvedt, Stein; Titelman, Josefin; Rø stad, Anders; Klevjer, Thor A.
2011-01-01
We examined the diel behavior among the jellyfish Periphylla periphylla in Lurefjorden, Norway in a sampling campaign and by a > 3-month continuous acoustic study. Jellyfish distribution and behavior were recorded by an upward-facing, bottom-mounted echo sounder at 280-m depth. The population was typically divided into four groups, each with different behavior. Individuals of behavioral Mode 1 undertook synchronous diel vertical migrations (DVM) within the upper 100 m. Individuals of behavioral Mode 2, stayed at ~ 160-200-m depth during the day, and also exhibited synchronized DVM, ascending at dusk and descending at dawn. The smaller individuals of behavioral Mode 3 swam continuously up and down throughout both day and night, yet occurred below Mode 2 individuals in daytime (~ 200 m-bottom), while their vertical range encompassed the entire water column during night. Mode 4 behavior was displayed by large jellyfish located between ~ 130 m and the bottom. These animals shifted between remaining motionless and relocating in rapid steps during both day and night. These four main behavioral patterns persisted throughout the registration period, although the synchronously migrating Mode 2 behavior became weaker in spring. This acoustic study has unveiled more diverse migration behaviors than previously derived from net sampling and remote-operated vehicles methods and emphasizes the importance of studying individuals. DVM is complex because individuals in a plankton population may simultaneously engage in a range of various contrasting behaviors.
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Beyond the average: Diverse individual migration patterns in a population of mesopelagic jellyfish
Kaartvedt, Stein
2011-11-01
We examined the diel behavior among the jellyfish Periphylla periphylla in Lurefjorden, Norway in a sampling campaign and by a > 3-month continuous acoustic study. Jellyfish distribution and behavior were recorded by an upward-facing, bottom-mounted echo sounder at 280-m depth. The population was typically divided into four groups, each with different behavior. Individuals of behavioral Mode 1 undertook synchronous diel vertical migrations (DVM) within the upper 100 m. Individuals of behavioral Mode 2, stayed at ~ 160-200-m depth during the day, and also exhibited synchronized DVM, ascending at dusk and descending at dawn. The smaller individuals of behavioral Mode 3 swam continuously up and down throughout both day and night, yet occurred below Mode 2 individuals in daytime (~ 200 m-bottom), while their vertical range encompassed the entire water column during night. Mode 4 behavior was displayed by large jellyfish located between ~ 130 m and the bottom. These animals shifted between remaining motionless and relocating in rapid steps during both day and night. These four main behavioral patterns persisted throughout the registration period, although the synchronously migrating Mode 2 behavior became weaker in spring. This acoustic study has unveiled more diverse migration behaviors than previously derived from net sampling and remote-operated vehicles methods and emphasizes the importance of studying individuals. DVM is complex because individuals in a plankton population may simultaneously engage in a range of various contrasting behaviors.
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Levels and patterns of internal migration in Europe: A cohort perspective.
Bernard, Aude
2017-11-01
Europe displays important variations in the level of internal migration, with a clear spatial gradient of high mobility in northern and western Europe but lower mobility in the south and east. However, cross-national variation in levels of internal migration remains poorly understood, because it is analysed almost exclusively using cross-sectional data and period measures. This paper seeks to advance understanding of cross-national variation in migration levels in 14 European countries by drawing on a recently proposed suite of migration cohort measures, coupled with internationally comparable retrospective residential histories. It shows that differences in migration levels are mainly attributable to variation in the extent of repeat movement, which is underpinned by the differences in mean ages at first and last move that together delineate the average length of migration careers. Cohort analysis provides a robust foundation for exploring the demographic mechanisms underpinning variation in migration levels across countries and over time.
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An Atomistic View on Human Hemoglobin Carbon Monoxide Migration Processes
Lucas, M. Fátima; Guallar, Víctor
2012-01-01
A significant amount of work has been devoted to obtaining a detailed atomistic knowledge of the human hemoglobin mechanism. Despite this impressive research, to date, the ligand diffusion processes remain unclear and controversial. Using recently developed computational techniques, PELE, we are capable of addressing the ligand migration processes. First, the methodology was tested on myoglobin's CO migration, and the results were compared with the wealth of theoretical and experimental studies. Then, we explored both hemoglobin tense and relaxed states and identified the differences between the α-and β-subunits. Our results indicate that the proximal site, equivalent to the Xe1 cavity in myoglobin, is never visited. Furthermore, strategically positioned residues alter the diffusion processes within hemoglobin's subunits and suggest that multiple pathways exist, especially diversified in the α-globins. A significant dependency of the ligand dynamics on the tertiary structure is also observed. PMID:22385860
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Forced migration: health and human rights issues among refugee populations.
Lori, Jody R; Boyle, Joyceen S
2015-01-01
Undocumented migration is a global phenomenon that is manifest in diverse contexts. In this article, we examine the situations that precipitate the movement of large numbers of people across several African countries, producing a unique type of undocumented migrant--the refugee. These refugee movements impact already fragile African health care systems and often involve human rights violations that are of particular concern, such as gender-based violence and child soldiers. We use examples from several countries in sub-Saharan Africa, including the Democratic Republic of the Congo, Rwanda, Liberia, Sierra Leone, and Mozambique. Drawing on key documents from the United Nations High Commissioner for Refugees, current research, and our personal international experiences, we provide an overview of forced migration and discuss implications and opportunities for nurses to impact research, practice, and policy related to refugee health. Copyright © 2015 Elsevier Inc. All rights reserved.
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Human mammary epithelial cells exhibit a bimodal correlated random walk pattern.
Potdar, Alka A; Jeon, Junhwan; Weaver, Alissa M; Quaranta, Vito; Cummings, Peter T
2010-03-10
Organisms, at scales ranging from unicellular to mammals, have been known to exhibit foraging behavior described by random walks whose segments confirm to Lévy or exponential distributions. For the first time, we present evidence that single cells (mammary epithelial cells) that exist in multi-cellular organisms (humans) follow a bimodal correlated random walk (BCRW). Cellular tracks of MCF-10A pBabe, neuN and neuT random migration on 2-D plastic substrates, analyzed using bimodal analysis, were found to reveal the BCRW pattern. We find two types of exponentially distributed correlated flights (corresponding to what we refer to as the directional and re-orientation phases) each having its own correlation between move step-lengths within flights. The exponential distribution of flight lengths was confirmed using different analysis methods (logarithmic binning with normalization, survival frequency plots and maximum likelihood estimation). Because of the presence of non-uniform turn angle distribution of move step-lengths within a flight and two different types of flights, we propose that the epithelial random walk is a BCRW comprising of two alternating modes with varying degree of correlations, rather than a simple persistent random walk. A BCRW model rather than a simple persistent random walk correctly matches the super-diffusivity in the cell migration paths as indicated by simulations based on the BCRW model.
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Human mammary epithelial cells exhibit a bimodal correlated random walk pattern.
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Alka A Potdar
2010-03-01
Full Text Available Organisms, at scales ranging from unicellular to mammals, have been known to exhibit foraging behavior described by random walks whose segments confirm to Lévy or exponential distributions. For the first time, we present evidence that single cells (mammary epithelial cells that exist in multi-cellular organisms (humans follow a bimodal correlated random walk (BCRW.Cellular tracks of MCF-10A pBabe, neuN and neuT random migration on 2-D plastic substrates, analyzed using bimodal analysis, were found to reveal the BCRW pattern. We find two types of exponentially distributed correlated flights (corresponding to what we refer to as the directional and re-orientation phases each having its own correlation between move step-lengths within flights. The exponential distribution of flight lengths was confirmed using different analysis methods (logarithmic binning with normalization, survival frequency plots and maximum likelihood estimation.Because of the presence of non-uniform turn angle distribution of move step-lengths within a flight and two different types of flights, we propose that the epithelial random walk is a BCRW comprising of two alternating modes with varying degree of correlations, rather than a simple persistent random walk. A BCRW model rather than a simple persistent random walk correctly matches the super-diffusivity in the cell migration paths as indicated by simulations based on the BCRW model.
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International Nuclear Information System (INIS)
Messi, Elio; Florian, Maria C; Caccia, Claudio; Zanisi, Mariarosa; Maggi, Roberto
2008-01-01
Neuroblastoma is a severe pediatric tumor, histologically characterised by a variety of cellular phenotypes. One of the pharmacological approaches to neuroblastoma is the treatment with retinoic acid. The mechanism of action of retinoic acid is still unclear, and the development of resistance to this differentiating agent is a great therapy problem. Doublecortin, a microtubule-associated protein involved in neuronal migration, has recently been proposed as a molecular marker for the detection of minimal residual disease in human neuroblastoma. Nevertheless, no information is available on the expression of doublecortin in the different cell-types composing human neuroblastoma, its correlation with neuroblastoma cell motility and invasiveness, and the possible modulations exerted by retinoic acid treatment. We analysed by immunofluorescence and by Western blot analysis the presence of doublecortin, lissencephaly-1 (another protein involved in neuronal migration) and of two intermediate filaments proteins, vimentin and neurofilament-68, in SK-N-SH human neuroblastoma cell line both in control conditions and under retinoic acid treatment. Migration and cell invasiveness studies were performed by wound scratch test and a modified microchemotaxis assay, respectively. Doublecortin is expressed in two cell subtypes considered to be the more aggressive and that show high migration capability and invasiveness. Vimentin expression is excluded by these cells, while lissencephaly-1 and neurofilaments-68 are immunodetected in all the cell subtypes of the SK-N-SH cell line. Treatment with retinoic acid reduces cell migration and invasiveness, down regulates doublecortin and lissencephaly-1 expression and up regulates neurofilament-68 expression. However, some cells that escape from retinoic acid action maintain migration capability and invasiveness and express doublecortin. a) Doublecortin is expressed in human neuroblastoma cells that show high motility and invasiveness; b
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Contemporary world migration - towards new terminology, patterns and policies
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Šantić Danica
2016-01-01
Full Text Available In the last decades, after the Cold War and the fall of the Berlin wall, the strengthening of overall population mobility is evident on local, regional, national and global scale. In addition, there are changes in the scope and direction of migration, their structural characteristics and increasing in the number of determining factors and consequences, which affects the complexity of this phenomenon. It is important to point out the emergence of new forms of migration as a result of intensifying pace of globalization, which is an integral part of the migration. The total number of migrants in the world (internal and external in the first decade of the XXI century reached the highest value in history and is around one billion, with small, but continuous increase in share of total population. This means that one in every seven person in the world has changed place of residence, either within their own country (about 700 million of internal migrants or moved to another country (244 million international migrants. Therefore some authors points out that all of us are becoming migrants. Also, the number of irregular migrants recently has reached its highest amount, which implies an intensification of government actions to regulate migration through the creation of effective policies, spatial mobility and intensification of bilateral, regional and international negotiations in this domain. Estimates show that the number of migrants will continue to grow, especially the number of climate migrants, persons who left their homes due to changes in the environment. That is why it is of crucial importance in a first place to understand migrations properly and then to create the steps towards the best solutions in solving the problems caused by population movement in space and create proper migration policies.
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Directory of Open Access Journals (Sweden)
Erik Corona
2013-05-01
Full Text Available Genetic diversity across different human populations can enhance understanding of the genetic basis of disease. We calculated the genetic risk of 102 diseases in 1,043 unrelated individuals across 51 populations of the Human Genome Diversity Panel. We found that genetic risk for type 2 diabetes and pancreatic cancer decreased as humans migrated toward East Asia. In addition, biliary liver cirrhosis, alopecia areata, bladder cancer, inflammatory bowel disease, membranous nephropathy, systemic lupus erythematosus, systemic sclerosis, ulcerative colitis, and vitiligo have undergone genetic risk differentiation. This analysis represents a large-scale attempt to characterize genetic risk differentiation in the context of migration. We anticipate that our findings will enable detailed analysis pertaining to the driving forces behind genetic risk differentiation.
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Human Chagas Disease and Migration in the Context of Globalization: Some Particular Aspects
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João Carlos Pinto Dias
2013-01-01
Full Text Available Human Chagas disease originated in Latin America, being spread around the world in relation with multiple bioecological, sociocultural, and political factors. The process of the disease production and dispersion is discussed, emphasizing the human migration and correlated aspects, in the context of globalization. Positive and negative consequences concern the future of this trypanosomiasis, mainly in terms of the ecologic and sociopolitical characteristics of the endemic and nonendemic countries.
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The workforce for health in a globalized context – global shortages and international migration
Aluttis, Christoph; Bishaw, Tewabech; Frank, Martina W.
2014-01-01
The ‘crisis in human resources’ in the health sector has been described as one of the most pressing global health issues of our time. The World Health Organization (WHO) estimates that the world faces a global shortage of almost 4.3 million doctors, midwives, nurses, and other healthcare professionals. A global undersupply of these threatens the quality and sustainability of health systems worldwide. This undersupply is concurrent with globalization and the resulting liberalization of markets, which allow health workers to offer their services in countries other than those of their origin. The opportunities of health workers to seek employment abroad has led to a complex migration pattern, characterized by a flow of health professionals from low- to high-income countries. This global migration pattern has sparked a broad international debate about the consequences for health systems worldwide, including questions about sustainability, justice, and global social accountabilities. This article provides a review of this phenomenon and gives an overview of the current scope of health workforce migration patterns. It further focuses on the scientific discourse regarding health workforce migration and its effects on both high- and low-income countries in an interdependent world. The article also reviews the internal and external factors that fuel health worker migration and illustrates how health workforce migration is a classic global health issue of our time. Accordingly, it elaborates on the international community's approach to solving the workforce crisis, focusing in particular on the WHO Code of Practice, established in 2010. PMID:24560265
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Choi, Hyunjung; Jin, Sun Hee; Han, Mi Hwa; Lee, Jinyoung; Ahn, Seyeon; Seong, Minjeong; Choi, Hyun; Han, Jiyeon; Cho, Eun-Gyung; Lee, Tae Ryong; Noh, Minsoo
2014-10-01
The interactions between human epidermal melanocytes and their cellular microenvironment are important in the regulation of human melanocyte functions or in their malignant transformation into melanoma. Although the basement membrane extracellular matrix (BM-ECM) is one of major melanocyte microenvironments, the effects of BM-ECM on the human melanocyte functions are not fully explained at a molecular level. This study was aimed to characterize the molecular and cellular interactions between normal human melanocytes (NHMs) and BM-ECM. We investigated cell culture models of normal human melanocytes or melanoma cells on three-dimensional (3D) Matrigel to understand the roles of the basement membrane microenvironment in human melanocyte functions. Melanogenesis and melanobast biomarker expression in both primary human melanocytes and melanoma cells on 3D Matrigel were evaluated. We found that NHMs migrated and formed reversible paired box 3 (PAX3) expressing cell clusters on three-dimensional (3D) Matrigel. The melanogenesis was significantly decreased in the PAX3 expressing cell cluster. The expression profile of PAX3, SOX10, and MITF in the melanocyte cluster on 3D Matrigel was similar to that of melanoblasts. Interestingly, PAX3 and SOX10 showed an inverse expression profile in NHMs, whereas the inverse expression pattern of PAX3 and SOX10 was disrupted in melanoma MNT1 and WM266-4 cells. The human melanocyte culture on 3D Matrigel provides an alternative model system to study functions of human melanoblasts. In addition, this system will contribute to the elucidation of PAX3-related tumorigenic mechanisms to understand human melanoma. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.
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Climate shocks and rural-urban migration in Mexico: Exploring nonlinearities and thresholds
Nawrotzki, Raphael J.; DeWaard, Jack; Bakhtsiyarava, Maryia; Ha, Jasmine Trang
2016-01-01
Adverse climatic conditions may differentially drive human migration patterns between rural and urban areas, with implications for changes in population composition and density, access to infrastructure and resources, and the delivery of essential goods and services. However, there is little empirical evidence to support this notion. In this study, we investigate the relationship between climate shocks and migration between rural and urban areas within Mexico. We combine individual records from the 2000 and 2010 Mexican censuses (n=683,518) with high-resolution climate data from Terra Populus that are linked to census data at the municipality level (n=2,321). We measure climate shocks as monthly deviation from a 30-year (1961-1990) long-term climate normal period, and uncover important nonlinearities using quadratic and cubic specifications. Satellite-based measures of urban extents allow us to classify migrant-sending and migrant-receiving municipalities as rural or urban to examine four internal migration patterns: rural-urban, rural-rural, urban-urban, and urban-rural. Among our key findings, results from multilevel models reveal that each additional drought month increases the odds of rural-urban migration by 3.6%. In contrast, the relationship between heat months and rural-urban migration is nonlinear. After a threshold of ~34 heat months is surpassed, the relationship between heat months and rural-urban migration becomes positive and progressively increases in strength. Policy and programmatic interventions may therefore reduce climate induced rural-urban migration in Mexico through rural climate change adaptation initiatives, while also assisting rural migrants in finding employment and housing in urban areas to offset population impacts. PMID:28435176
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Li, Miao; Anderson, James G
2016-08-01
Drawing on the life course perspective and the assumptive world theory, this paper examines whether pre-migration trauma exposure is associated with psychological distress through post-migration perceived discrimination for Asian American immigrants. The study is based on cross-sectional data from the National Latino and Asian American Study (N = 1639). Structural equation model is used to estimate the relationship between pre-migration trauma, post-migration perceived discrimination, and psychological distress. Additional models are estimated to explore possible variations across ethnic groups as well as across different types of pre-migration trauma experience. Pre-migration trauma exposure is associated with higher levels of psychological distress, both directly and indirectly through higher level of perceived discrimination, even after controlling for demographic/acculturative factors and post-migration trauma exposure. This pattern holds for the following sub-types of pre-migration trauma: political trauma, crime victimization, physical violence, accidental trauma, and relational trauma. Multi-group analyses show that this pattern holds for all Asian immigrant subgroups except the Vietnamese. Studies of immigrant mental health primarily focus on post-migration stressors. Few studies have considered the link between pre- and post-migration contexts in assessing mental health outcomes. The study illustrates the usefulness of bridging the pre- and post-migration context in identifying the mental health risks along the immigrant life course.
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DEFF Research Database (Denmark)
Thorstad, E.B.; Okland, F.; Aarestrup, Kim
2008-01-01
experience, water discharge, water temperature, water velocity, required jump heights, fish size, fish acclimatisation, light, water quality/pollution, time of the season, and catch and handling stress. How each of these factors affects the upstream migration is to a varying extent understood; however...... be delayed at natural migration barriers. Often, the magnitude of delay is not predictable; fish may be considerably delayed at barriers that appear to humans to be easily passable, or they may quickly pass barriers that appear difficult. Stressful events like catch-and-release angling may affect upstream...... predicted under which conditions a fish will pass a given migration barrier or which conditions are needed to stimulate migration at different sites. The strong focus on the effects of water discharge in past work may have hampered consideration of other factors. Exploration of the influence of these other...
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Staby, A
2011-11-15
We studied the temporal dynamics in the vertical distribution of Maurolicus muelleri scattering layers (SL) by examining continuous acoustic recordings over a 15 mo period in Masfjorden, Norway, complemented by intermittent sampling campaigns. The data revealed known patterns as normal diel vertical migration (DVM), midnight sinking between dusk and dawn, and periods without migrations, as well as novel behaviours consisting of early morning ascents, reverse diel vertical migrations, and interrupted ascents in the evening. During the first autumn of the study, adult fish modified their normal DVM behaviour by suspending their migration in the evening, yet ascending toward the surface in the later part of the night to reach upper layers during dawn. This behaviour was not observed during the second autumn of the study. By mid- to end of November (1st autumn), adult fish had suspended the nocturnal ascent entirely, and in the subsequent period until the end of January, a fraction of the population rather performed limited reverse migrations, slightly shifting their vertical distribution upwards during the first part of the day. From January to March 2008, fish interrupted their evening ascent at apparently random intervals and returned to deeper waters, instead of completing a full ascent to the surface. Our study underlines the value of long-term recordings, with the results suggesting that M. muelleri has the capability of changing its behaviour in response to ontogeny and internal state (satiation and hunger) as well as to external stimuli.
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Mission, migration and human development: A new approach
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Akinyemi O. Alawode
2015-07-01
Full Text Available Migration has been a fact of Judaeo-Christian life since the days when Abram left Ur of the Chaldeans to find God’s promised land. It has become a far greater reality since the late 20th century, mainly as a result of wars, intranational conflicts, and natural disasters. As a result we have to deal with a larger number of internally or externally displaced persons (migrants in Africa at the beginning of the 21st century than ever before. At the same time Africa reports on record numbers in terms of church growth. It is therefore clear that migration and Christian mission to migrants are serious items on the agenda of Christian mission in Africa. The article argues that migration is largely a result of a growing phenomenon of dehumanisation in Africa and worldwide: people tend to regard other people no longer as fellow human beings, created in the image of God. For this reason a very important missionary responsibility is topromote humanisation according to the gospel proclaimed by the new human being, Jesus of Nazareth. This calls for human development of migrants as well as indigenous Christians. It is my contention that the Christian community in Africa has not yet grasped this missionary vocation as it should have. Therefore, the article argues that Christian mission in Africa faces the task of humanising relationships between indigenous Christians and other migrants, and that this can be done through a well-developed programme of human development in which both migrants and indigenous Christians should participate. Sending, migrasie en menslike ontwikkeling: ’n Nuwe benadering. Migrasie is ’n realiteit van die Judese-Christelike lewe sedert Abram Ur van die Galdeërs verlaat het om God se beloofde land te vind. Dit het egter ’n groter realiteit geword sedert die laat twintigste eeu hoofsaaklik as gevolg van oorloë, intranasionale konflik en natuurrampe. As gevolg hiervan moes daar na ’n groter getal migrante in Afrika omgesien
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miR-151-3p Targets TWIST1 to Repress Migration of Human Breast Cancer Cells.
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Ting-Chih Yeh
Full Text Available TWIST1 is a highly conserved basic helix-loop-helix transcription factor that contributes to cancer metastasis by promoting an epithelial-mesenchymal transition and repressing E-cadherin gene expression in breast cancer. In this study, we explored the potential role of miR-151 in TWIST1 expression and cancer properties in human breast cancer cells. We found that the human TWIST1 3'UTR contains a potential binging site for miR-151-3p at the putative target sequence 5'-CAGUCUAG-3'. Using a TWIST1-3'UTR luciferase reporter assay, we demonstrated that the target sequence within the TWIST1 3'UTR is required for miR-151-3p regulation of TWIST1 expression. Moreover, we found that ectopic expression of miR-151-3p by infection with adenoviruses expressing miR-151 significantly decreased TWIST1 expression, migration and invasion, but did not affect cell growth and tumorsphere formation of human breast cancer cells. In addition, overexpression of the protein coding region without the 3'UTR of TWIST1 reversed the repression of cell migration by miR-151-3p. Furthermore, knockdown of miR-151-3p increased TWIST1 expression, reduced E-cadherin expression, and enhanced cell migration. In conclusion, these results suggest that miR-151-3p directly regulates TWIST1 expression by targeting the TWIST1 3'UTR and thus repressing the migration and invasion of human breast cancer cells by enhancing E-cadherin expression. Our findings add to accumulating evidence that microRNAs are involved in breast cancer progression by modulating TWIST1 expression.
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Directory of Open Access Journals (Sweden)
Sharang Ghavampour
Full Text Available Local inflammatory responses are characterized by the recruitment of circulating leukocytes from the blood to sites of inflammation, a process requiring the directed migration of leukocytes across the vessel wall and hence a penetration of the endothelial lining. To identify underlying signalling events and novel factors involved in these processes we screened for genes differentially expressed in human monocytes following their adhesion to and passage through an endothelial monolayer. Functional annotation clustering of the genes identified revealed an overrepresentation of those associated with inflammation/immune response, in particular early monocyte to macrophage differentiation. Among the gene products so far not implicated in monocyte transendothelial migration was the inhibitory immune receptor CD300a. CD300a mRNA and protein levels were upregulated following transmigration and engagement of the receptor by anti-CD300a antibodies markedly reduced monocyte transendothelial migration. In contrast, siRNA mediated downregulation of CD300a in human monocytes increased their rate of migration. CD300a colocalized and cosedimented with actin filaments and, when activated, caused F-actin cytoskeleton alterations. Thus, monocyte transendothelial migration is accompanied by an elevation of CD300a which serves an inhibitory function possibly required for termination of the actual transmigration.
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Population, migration and urbanization.
1982-06-01
Despite recent estimates that natural increase is becoming a more important component of urban growth than rural urban transfer (excess of inmigrants over outmigrants), the share of migration in the total population growth has been consistently increasing in both developed and developing countries. From a demographic perspective, the migration process involves 3 elements: an area of origin which the mover leaves and where he or she is considered an outmigrant; the destination or place of inmigration; and the period over which migration is measured. The 2 basic types of migration are internal and international. Internal migration consists of rural to urban migration, urban to urban migration, rural to rural migration, and urban to rural migration. Among these 4 types of migration various patterns or processes are followed. Migration may be direct when the migrant moves directly from the village to the city and stays there permanently. It can be circular migration, meaning that the migrant moves to the city when it is not planting season and returns to the village when he is needed on the farm. In stage migration the migrant makes a series of moves, each to a city closer to the largest or fastest growing city. Temporary migration may be 1 time or cyclical. The most dominant pattern of internal migration is rural urban. The contribution of migration to urbanization is evident. For example, the rapid urbanization and increase in urban growth from 1960-70 in the Republic of Korea can be attributed to net migration. In Asia the largest component of the population movement consists of individuals and groups moving from 1 rural location to another. Recently, because urban centers could no longer absorb the growing number of migrants from other places, there has been increased interest in the urban to rural population redistribution. This reverse migration also has come about due to slower rates of employment growth in the urban centers and improved economic opportunities
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Inclusive growth?: Labour migration and poverty in India
Haan, Arjan
2011-01-01
textabstractThis paper discusses the relationship between labour migration and poverty in India. This is placed against the on-going debates on changes in patterns of employment and job creation in India, during the periods of economic liberalization, under the Inclusive Growth policies since 2004, and under the impact of the global financial crisis, and growing inequalities. The paper focuses on the migration patterns of deprived social groups, analyse whether migration form a routes out of ...
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DEFINING HUMAN MIGRATION – A POLICY MAKERS PERSPECTIVE
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Paul-Panfil IVAN
2015-06-01
Full Text Available Migration is a global phenomenon gradually increased in scope, impact and complexity. Practically all countries are simultaneously countries of destination, origin and transit for migrants. Traditionally migration flows are complemented by new changes generated by economic, demographic, political or social conditions, and these trends affect both the size and structure of the migrant population and also economies and societies. Of course this has sparked international interest from various NGOs and by the European Union and the United Nations. This paper aims to present the vision of international organizations concerned with migration and how they define migration and its typologies.
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Chain Migration through Social Networks: Case Study of Vietnamese Migrants in Thailand
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Anh Tuan NGUYEN
2016-11-01
Full Text Available The paper aims to investigate the relationship between the recent increasingly pattern of Vietnamese migrants in Thailand and migration networks. By surveying 50 Vietnamese migrants in Bangkok, Thailand, the study confirms that migration networks have played a critical role in facilitating migration flows, especially irregular flows from Vietnam to Thailand over the years. It can be reflected by reducing the cost of migration, coping with new working environment and risks during working in Thailand and ensuring the return process for Vietnamese migrants. Moreover, forms of social networks includes personal networks (kinship and friendship networks, and community network (ngườidẫnđường’s network, social media has been also discussed. The study also implies that the người dẫn đường’s networks might contribute to recently emerging issues such as human trafficking and smugglings, which require further research.
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Wang, Kai; Li, Yan; Jiang, Yi-Zhou; Dai, Cai-Feng; Patankar, Manish S; Song, Jia-Sheng; Zheng, Jing
2013-10-28
The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor mediates many biological processes. Herein, we investigated if 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE, an endogenous AhR ligand) regulated proliferation and migration of human ovarian cancer cells via AhR. We found that AhR was widely present in many histotypes of ovarian cancer tissues. ITE suppressed OVCAR-3 cell proliferation and SKOV-3 cell migration in vitro, which were blocked by AhR knockdown. ITE also suppressed OVCAR-3 cell growth in mice. These data suggest that the ITE might potentially be used for therapeutic intervention for at least a subset of human ovarian cancer. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
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Migration patterns of the elderly: the case of the American Jewish population.
Rosenwaike, I
1989-01-01
"This article examines the growing concentration of the elderly Jewish population of the U.S. in one metropolitan region of the Sun Belt. The principal data sources used are U.S. Census counts of the population with a Yiddish mother tongue or speaking Yiddish at home, as well as 1980 data on the population of Russian ancestry. The limitations of these measures are discussed and data from local community surveys also are presented. The data show that relocation of the elderly from the North, especially to South Florida, has been occurring since the 1950s and accelerated during the 1970s. The need for further study, which may document the migration patterns of elderly members of diverse religions and ethnic groups, is pointed out." excerpt
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Sato, Takashi; Watanabe, Mami; Hashimoto, Kei; Ota, Tomoko; Akimoto, Noriko; Imada, Keisuke; Nomizu, Motoyoshi; Ito, Akira
2012-01-01
EMMPRIN (extracellular matrix metalloproteinase inducer)/CD147, a membrane-bound glycoprotein with two extracellular loop domains (termed loops I and II), progresses tumor invasion and metastasis by increasing the production of matrix metalloproteinase (MMP) in peritumoral stoma cells. EMMPRIN has also been associated with the control of migration activity in some tumor cells, but little is known about how EMMPRIN regulates tumor cell migration. In the present study, EMMPRIN siRNA suppressed the gene expression and production of EMMPRIN in human uterine cervical carcinoma SKG-II cells. An in vitro scratch wound assay showed enhancement of migration of EMMPRIN-knockdown SKG-II cells. In addition, the SKG-II cell migration was augmented by adding an E. coli-expressed human EMMPRIN mutant with two extracellular loop domains (eEMP-I/II), which bound to the cell surface of SKG-II cells. However, eEMP-I/II suppressed the native EMMPRIN-mediated augmentation of proMMP-1/procollagenase-1 production in a co-culture of the SKG-II cells and human uterine cervical fibroblasts, indicating that the augmentation of SKG-II cell migration resulted from the interference of native EMMPRIN functions by eEMP-I/II on the cell surface. Furthermore, a systematic peptide screening method using nine synthetic EMMPRIN peptides coding the loop I and II domains (termed EM1-9) revealed that EM9 (170HIENLNMEADPGQYR184) facilitated SKG-II cell migration. Moreover, SKG-II cell migration was enhanced by administration of an antibody against EM9, but not EM1 which is a crucial site for the MMP inducible activity of EMMPRIN. Therefore, these results provide novel evidence that EMMPRIN on the cell surface limits the cell migration of human uterine cervical carcinoma cells through 170HIENLNMEADPGQYR184 in the loop II domain. Finally, these results should provide an increased understanding of the functions of EMMPRIN in malignant cervical carcinoma cells, and could contribute to the development of
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Czech Academy of Sciences Publication Activity Database
Brož, Antonín; Ukraintsev, Egor; Kromka, Alexander; Rezek, Bohuslav; Kalbáčová, M.H.
2017-01-01
Roč. 105, č. 5 (2017), s. 1469-1478 ISSN 1549-3296 R&D Projects: GA ČR(CZ) GA14-04790S; GA MZd(CZ) NV15-32497A Institutional support: RVO:67985823 ; RVO:68378271 Keywords : live-cell imaging * osteoblasts * adhesion * proliferation * migration * patterned surface Subject RIV: EI - Biotechnology ; Bionics OBOR OECD: Biomaterials (as related to medical implants, devices, sensors) Impact factor: 3.076, year: 2016
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Directory of Open Access Journals (Sweden)
Silvestre, Javier
2011-04-01
Full Text Available This article extends the existing literature on the internal migration patterns of the foreign-born in Spain. We analyze the spatial distribution of immigrants and their patterns of mobility at different levels. Socio-demographic characteristics of immigrants and characteristics of places of origin and destination are considered. We also examine repeat migration, duration of residence in each destination, as well as return migration within Spain. To this end, we make use of a new micro database corresponding to the National Immigrant Survey (Encuesta Nacional de Inmigrantes, ENI-2007.
Este artículo contribuye a la literatura sobre la migración interna de los inmigrantes nacidos fuera de España. En él se analiza la distribución espacial y las pautas de movilidad de los inmigrantes, considerando aspectos como las características sociodemográficas de los individuos y las características de los orígenes y destinos dentro de España. También se analiza la emigración repetida, la duración de la residencia en cada destino y la emigración de retorno (dentro de España. Para todo ello, se utiliza la nueva base de datos micro derivada de la Encuesta Nacional de Inmigrantes, ENI-2007. -
Kessel, Steven T; Hondorp, Darryl W; Holbrook, Christopher M; Boase, James C; Chiotti, Justin A; Thomas, Michael V; Wills, Todd C; Roseman, Edward F; Drouin, Richard; Krueger, Charles C
2018-01-01
Population structure, distribution, abundance and dispersal arguably underpin the entire field of animal ecology, with consequences for regional species persistence, and provision of ecosystem services. Divergent migration behaviours among individuals or among populations are an important aspect of the ecology of highly mobile animals, allowing populations to exploit spatially or temporally distributed food and space resources. This study investigated the spatial ecology of lake sturgeon (Acipenser fulvescens) within the barrier free Huron-Erie Corridor (HEC), which connects Lake Huron and Lake Erie of the North American Laurentian Great Lakes. Over 6 years (2011-2016), movements of 268 lake sturgeon in the HEC were continuously monitored across the Great Lakes using acoustic telemetry (10 years battery life acoustic transmitters). Five distinct migration behaviours were identified with hierarchical cluster analysis, based on the phenology and duration of river and lake use. Lake sturgeon in the HEC were found to contain a high level of intraspecific divergent migration, including partial migration with the existence of residents. Specific behaviours included year-round river residency and multiple lake-migrant behaviours that involved movements between lakes and rivers. Over 85% of individuals were assigned to migration behaviours as movements were consistently repeated over the study, which suggested migration behaviours were consistent and persistent in lake sturgeon. Differential use of specific rivers or lakes by acoustic-tagged lake sturgeon further subdivided individuals into 14 "contingents" (spatiotemporally segregated subgroups). Contingents associated with one river (Detroit or St. Clair) were rarely detected in the other river, which confirmed that lake sturgeon in the Detroit and St. Clair represent two semi-independent populations that could require separate management consideration for their conservation. The distribution of migration behaviours
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Kessel, Steven T.; Hondorp, Darryl W.; Holbrook, Christopher; Boase, James C.; Chiotti, Justin A.; Thomas, Michael V.; Wills, Todd C.; Roseman, Edward; Drouin, Richard; Krueger, Charles C.
2018-01-01
Population structure, distribution, abundance, and dispersal arguably underpin the entire field of animal ecology, with consequences for regional species persistence, and provision of ecosystem services. Divergent migration behaviours among individuals or among populations is an important aspect of the ecology of highly-mobile animals, allowing populations to exploit spatially- or temporally-distributed food and space resources.This study investigated the spatial ecology of lake sturgeon (Acipenser fulvescens) within the barrier free Huron-Erie Corridor (HEC), which connects Lake Huron and Lake Erie of the North American Laurentian Great Lakes.Over six years (2011 – 2016), movements of 268 lake sturgeon in the HEC were continuously monitored across the Great Lakes using acoustic telemetry (10 yr battery life acoustic transmitters). Five distinct migration behaviours were identified with hierarchical cluster analysis, based on the phenology and duration of river and lake use.Lake sturgeon in the HEC were found to contain a high level of intraspecific divergent migration, including partial migration with the existence of residents. Specific behaviours included year-round river residency and multiple lake-migrant behaviours that involved movements between lakes and rivers. Over 85% of individuals were assign to migration behaviours as movements were consistently repeated over the study, which suggested migration behaviours were consistent and persistent in lake sturgeon. Differential use of specific rivers or lakes by acoustic-tagged lake sturgeon further subdivided individuals into 14 “contingents” (spatiotemporally segregated subgroups).Contingents associated with one river (Detroit or St. Clair) were rarely detected in the other river, which confirmed that lake sturgeon in the Detroit and St. Clair represent two semi-independent populations that could require separate management consideration for their conservation. The distribution of migration behaviours
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Energy Technology Data Exchange (ETDEWEB)
Giometti, C.S. (Argonne National Lab., IL); Barany, M.; Danon, M.J.; Anderson, N.G.
1980-07-01
High-resolution two-dimensional electrophoresis was used to analyze the major proteins of normal and pathological human-muscle samples. The normal human-muscle pattern contains four myosin light chains: three that co-migrate with the myosin light chains from rabbit fast muscle (extensor digitorum longus), and one that co-migrates with the light chain 2 from rabbit slow muscle (soleus). Of seven Duchenne muscular dystrophy samples, four yielded patterns with decreased amounts of actin and myosin relative to normal muscle, while three samples gave patterns comparable to that for normal muscle. Six samples from patients with myotonic dystrophy also gave normal patterns. In nemaline rod myopathy, in contrast, the pattern was deficient in two of the fast-type myosin light chains.
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Migrating mule deer: effects of anthropogenically altered landscapes.
Directory of Open Access Journals (Sweden)
Patrick E Lendrum
Full Text Available Migration is an adaptive strategy that enables animals to enhance resource availability and reduce risk of predation at a broad geographic scale. Ungulate migrations generally occur along traditional routes, many of which have been disrupted by anthropogenic disturbances. Spring migration in ungulates is of particular importance for conservation planning, because it is closely coupled with timing of parturition. The degree to which oil and gas development affects migratory patterns, and whether ungulate migration is sufficiently plastic to compensate for such changes, warrants additional study to better understand this critical conservation issue.We studied timing and synchrony of departure from winter range and arrival to summer range of female mule deer (Odocoileus hemionus in northwestern Colorado, USA, which has one of the largest natural-gas reserves currently under development in North America. We hypothesized that in addition to local weather, plant phenology, and individual life-history characteristics, patterns of spring migration would be modified by disturbances associated with natural-gas extraction. We captured 205 adult female mule deer, equipped them with GPS collars, and observed patterns of spring migration during 2008-2010.Timing of spring migration was related to winter weather (particularly snow depth and access to emerging vegetation, which varied among years, but was highly synchronous across study areas within years. Additionally, timing of migration was influenced by the collective effects of anthropogenic disturbance, rate of travel, distance traveled, and body condition of adult females. Rates of travel were more rapid over shorter migration distances in areas of high natural-gas development resulting in the delayed departure, but early arrival for females migrating in areas with high development compared with less-developed areas. Such shifts in behavior could have consequences for timing of arrival on birthing areas
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Dispersal time for ancient human migrations: Americas and Europe colonization
Flores, J. C.
2007-07-01
I apply the recently proposed intermittence strategy to investigate the ancient human migrations in the world. That is, the Americas colonization (Bering-bridge and Pacific-coast theories) and Neanderthal replacement in Europe around 45000 years before the present. Using a mathematical equation related to diffusion and ballistic motion, I calculate the colonization time in all these cases in good agreement with archeological data (including Neolithic transition in Europe). Moreover, to support these calculations, I obtain analytically the effective speed of colonization in Europe veff=0.62 [km/yr] and related to the Aurignacian culture propagation.
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Wöllert, Torsten; Langford, George M
2016-01-01
Long-term live cell imaging was used in this study to determine the responses of human epithelial cells to pathogenic biofilms formed by Candida albicans. Epithelial cells of the skin represent the front line of defense against invasive pathogens such as C. albicans but under certain circumstances, especially when the host's immune system is compromised, the skin barrier is breached. The mechanisms by which the fungal pathogen penetrates the skin and invade the deeper layers are not fully understood. In this study we used keratinocytes grown in culture as an in vitro model system to determine changes in host cell migration and the actin cytoskeleton in response to virulence factors produced by biofilms of pathogenic C. albicans. It is clear that changes in epithelial cell migration are part of the response to virulence factors secreted by biofilms of C. albicans and the actin cytoskeleton is the downstream effector that mediates cell migration. Our goal is to understand the mechanism by which virulence factors hijack the signaling pathways of the actin cytoskeleton to alter cell migration and thereby invade host tissues. To understand the dynamic changes of the actin cytoskeleton during infection, we used long-term live cell imaging to obtain spatial and temporal information of actin filament dynamics and to identify signal transduction pathways that regulate the actin cytoskeleton and its associated proteins. Long-term live cell imaging was achieved using a high resolution, multi-mode epifluorescence microscope equipped with specialized light sources, high-speed cameras with high sensitivity detectors, and specific biocompatible fluorescent markers. In addition to the multi-mode epifluorescence microscope, a spinning disk confocal long-term live cell imaging system (Olympus CV1000) equipped with a stage incubator to create a stable in vitro environment for long-term real-time and time-lapse microscopy was used. Detailed descriptions of these two long-term live
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Migration, human capital, and growth in a globalized economy
Burzynski, Michal
2016-01-01
This thesis focuses on the implications of past, and hypothetical future movements of people for the prosperity of natives and residents living in the highly developed regions. The first Chapter discusses the welfare impact of migration in the OECD countries by analyzing recent migration flows (net migration between 2000 and 2010), and total stock of migrants in 2010. The importance of different channels, through which migration affects the wellbeing of stayers, is discussed. In the second Ch...
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Emergent patterns of collective cell migration under tubular confinement.
Xi, Wang; Sonam, Surabhi; Beng Saw, Thuan; Ladoux, Benoit; Teck Lim, Chwee
2017-11-15
Collective epithelial behaviors are essential for the development of lumens in organs. However, conventional assays of planar systems fail to replicate cell cohorts of tubular structures that advance in concerted ways on out-of-plane curved and confined surfaces, such as ductal elongation in vivo. Here, we mimic such coordinated tissue migration by forming lumens of epithelial cell sheets inside microtubes of 1-10 cell lengths in diameter. We show that these cell tubes reproduce the physiological apical-basal polarity, and have actin alignment, cell orientation, tissue organization, and migration modes that depend on the extent of tubular confinement and/or curvature. In contrast to flat constraint, the cell sheets in a highly constricted smaller microtube demonstrate slow motion with periodic relaxation, but fast overall movement in large microtubes. Altogether, our findings provide insights into the emerging migratory modes for epithelial migration and growth under tubular confinement, which are reminiscent of the in vivo scenario.
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The Enemy at the Gates: International Borders, Migration and Human Rights
Directory of Open Access Journals (Sweden)
Pia Oberoi
2013-07-01
Full Text Available This article considers contemporary border management regimes from a human rights perspective. It demonstrates how a preoccupation with border controls and enforcement has led to serious concerns for the safety and protection of migrants. As border zones have expanded, border crossing has become a more stigmatized and dangerous activity, and even as globalization has given rise to easier and faster international travel, for some, such movement has been outlawed and stigmatized. Measures to strengthen and “secure” borders have paradoxically made migrants, particularly irregular and vulnerable migrants, more at risk of violence and exploitation by non-State and State actors. Migration governance regimes at international borders are thus increasingly located within security and enforcement frameworks that pay little attention to the principles and standards of international human rights law. The paper argues that a human rights-based approach to such regimes is urgently needed, in order to address a growing human rights crisis at international borders.
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Conservation physiology of animal migration
Lennox, Robert J.; Chapman, Jacqueline M.; Souliere, Christopher M.; Tudorache, Christian; Wikelski, Martin; Metcalfe, Julian D.; Cooke, Steven J.
2016-01-01
Migration is a widespread phenomenon among many taxa. This complex behaviour enables animals to exploit many temporally productive and spatially discrete habitats to accrue various fitness benefits (e.g. growth, reproduction, predator avoidance). Human activities and global environmental change represent potential threats to migrating animals (from individuals to species), and research is underway to understand mechanisms that control migration and how migration responds to modern challenges. Focusing on behavioural and physiological aspects of migration can help to provide better understanding, management and conservation of migratory populations. Here, we highlight different physiological, behavioural and biomechanical aspects of animal migration that will help us to understand how migratory animals interact with current and future anthropogenic threats. We are in the early stages of a changing planet, and our understanding of how physiology is linked to the persistence of migratory animals is still developing; therefore, we regard the following questions as being central to the conservation physiology of animal migrations. Will climate change influence the energetic costs of migration? Will shifting temperatures change the annual clocks of migrating animals? Will anthropogenic influences have an effect on orientation during migration? Will increased anthropogenic alteration of migration stopover sites/migration corridors affect the stress physiology of migrating animals? Can physiological knowledge be used to identify strategies for facilitating the movement of animals? Our synthesis reveals that given the inherent challenges of migration, additional stressors derived from altered environments (e.g. climate change, physical habitat alteration, light pollution) or interaction with human infrastructure (e.g. wind or hydrokinetic turbines, dams) or activities (e.g. fisheries) could lead to long-term changes to migratory phenotypes. However, uncertainty remains
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A space oddity: geographic and specific modulation of migration in Eudyptes penguins.
Thiebot, Jean-Baptiste; Cherel, Yves; Crawford, Robert J M; Makhado, Azwianewi B; Trathan, Philip N; Pinaud, David; Bost, Charles-André
2013-01-01
Post-breeding migration in land-based marine animals is thought to offset seasonal deterioration in foraging or other important environmental conditions at the breeding site. However the inter-breeding distribution of such animals may reflect not only their optimal habitat, but more subtle influences on an individual's migration path, including such factors as the intrinsic influence of each locality's paleoenvironment, thereby influencing animals' wintering distribution. In this study we investigated the influence of the regional marine environment on the migration patterns of a poorly known, but important seabird group. We studied the inter-breeding migration patterns in three species of Eudyptes penguins (E. chrysolophus, E. filholi and E. moseleyi), the main marine prey consumers amongst the World's seabirds. Using ultra-miniaturized logging devices (light-based geolocators) and satellite tags, we tracked 87 migrating individuals originating from 4 sites in the southern Indian Ocean (Marion, Crozet, Kerguelen and Amsterdam Islands) and modelled their wintering habitat using the MADIFA niche modelling technique. For each site, sympatric species followed a similar compass bearing during migration with consistent species-specific latitudinal shifts. Within each species, individuals breeding on different islands showed contrasting migration patterns but similar winter habitat preferences driven by sea-surface temperatures. Our results show that inter-breeding migration patterns in sibling penguin species depend primarily on the site of origin and secondly on the species. Such site-specific migration bearings, together with similar wintering habitat used by parapatrics, support the hypothesis that migration behaviour is affected by the intrinsic characteristics of each site. The paleo-oceanographic conditions (primarily, sea-surface temperatures) when the populations first colonized each of these sites may have been an important determinant of subsequent migration
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A space oddity: geographic and specific modulation of migration in Eudyptes penguins.
Directory of Open Access Journals (Sweden)
Jean-Baptiste Thiebot
Full Text Available Post-breeding migration in land-based marine animals is thought to offset seasonal deterioration in foraging or other important environmental conditions at the breeding site. However the inter-breeding distribution of such animals may reflect not only their optimal habitat, but more subtle influences on an individual's migration path, including such factors as the intrinsic influence of each locality's paleoenvironment, thereby influencing animals' wintering distribution. In this study we investigated the influence of the regional marine environment on the migration patterns of a poorly known, but important seabird group. We studied the inter-breeding migration patterns in three species of Eudyptes penguins (E. chrysolophus, E. filholi and E. moseleyi, the main marine prey consumers amongst the World's seabirds. Using ultra-miniaturized logging devices (light-based geolocators and satellite tags, we tracked 87 migrating individuals originating from 4 sites in the southern Indian Ocean (Marion, Crozet, Kerguelen and Amsterdam Islands and modelled their wintering habitat using the MADIFA niche modelling technique. For each site, sympatric species followed a similar compass bearing during migration with consistent species-specific latitudinal shifts. Within each species, individuals breeding on different islands showed contrasting migration patterns but similar winter habitat preferences driven by sea-surface temperatures. Our results show that inter-breeding migration patterns in sibling penguin species depend primarily on the site of origin and secondly on the species. Such site-specific migration bearings, together with similar wintering habitat used by parapatrics, support the hypothesis that migration behaviour is affected by the intrinsic characteristics of each site. The paleo-oceanographic conditions (primarily, sea-surface temperatures when the populations first colonized each of these sites may have been an important determinant of
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International Nuclear Information System (INIS)
Liu, Xueting; Fang, Shencun; Liu, Haijun; Wang, Xingang; Dai, Xiaoniu; Yin, Qing; Yun, Tianwei; Wang, Wei; Zhang, Yingming; Liao, Hong; Zhang, Wei; Yao, Honghong; Chao, Jie
2015-01-01
Background: Silicosis is a systemic disease caused by inhaling silicon dioxide (SiO 2 ). Phagocytosis of SiO 2 in the lung initiates an inflammatory cascade that results in fibroblast proliferation and migration and subsequent fibrosis. Clinical evidence indicates that the activation of alveolar macrophages by SiO 2 produces rapid and sustained inflammation that is characterized by the generation of monocyte chemotactic protein 1 (MCP-1), which induces fibrosis. Pulmonary fibroblast-derived MCP-1 may play a critical role in fibroblast proliferation and migration. Methods and results: Experiments using primary cultured adult human pulmonary fibroblasts (HPF-a) demonstrated the following results: 1) SiO 2 treatment resulted in the rapid and sustained induction of MCP-1 as well as the elevation of the CC chemokine receptor type 2 (CCR2) protein levels; 2) pretreatment of HPF-a with RS-102895, a specific CCR2 inhibitor, abolished the SiO 2 -induced increase in cell activation and migration in both 2D and 3D culture systems; and 3) RNA interference targeting CCR2 prevented the SiO 2 -induced increase in cell migration. Conclusion: These data demonstrated that the up-regulation of pulmonary fibroblast-derived MCP-1 is involved in pulmonary fibroblast migration induced by SiO 2 . CCR2 was also up-regulated in response to SiO 2 , and this up-regulation facilitated the effect of MCP-1 on fibroblasts. Our study deciphered the link between fibroblast-derived MCP-1 and SiO 2 -induced cell migration. This finding provides novel insight into the potential of MCP-1 in the development of novel therapeutic strategies for silicosis. - Highlights: • Role of pulmonary fibroblast-derived MCP-1 in experimental silicosis was studied. • SiO 2 induced MCP-1 release from cultured human pulmonary fibroblast (HPF-a). • SiO 2 directly activated HPF-a via the MCP-1/CCR2 pathway. • SiO 2 increased HPF-a migration in both 2D and 3D model via the MCP-1/CCR2 pathway. • RNA-i of MCP-1/CCR2
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Energy Technology Data Exchange (ETDEWEB)
Liu, Xueting [Department of Physiology, Medical School of Southeast University, Nanjing, Jiangsu 210009 (China); Fang, Shencun [Nine Department of Respiratory Medicine, Nanjing Chest Hospital, Nanjing, Jiangsu 210029 (China); Liu, Haijun [Neurobiology Laboratory, New Drug Screening Centre, China Pharmaceutical University, Nanjing, Jiangsu 210009 (China); Wang, Xingang; Dai, Xiaoniu; Yin, Qing; Yun, Tianwei [Department of Physiology, Medical School of Southeast University, Nanjing, Jiangsu 210009 (China); Wang, Wei; Zhang, Yingming [Nine Department of Respiratory Medicine, Nanjing Chest Hospital, Nanjing, Jiangsu 210029 (China); Liao, Hong [Neurobiology Laboratory, New Drug Screening Centre, China Pharmaceutical University, Nanjing, Jiangsu 210009 (China); Zhang, Wei [Department of Physiology, Medical School of Southeast University, Nanjing, Jiangsu 210009 (China); Yao, Honghong [Department of Pharmacology, Medical School of Southeast University, Nanjing, Jiangsu 210009 (China); Chao, Jie, E-mail: chaojie@seu.edu.cn [Department of Physiology, Medical School of Southeast University, Nanjing, Jiangsu 210009 (China)
2015-10-15
Background: Silicosis is a systemic disease caused by inhaling silicon dioxide (SiO{sub 2}). Phagocytosis of SiO{sub 2} in the lung initiates an inflammatory cascade that results in fibroblast proliferation and migration and subsequent fibrosis. Clinical evidence indicates that the activation of alveolar macrophages by SiO{sub 2} produces rapid and sustained inflammation that is characterized by the generation of monocyte chemotactic protein 1 (MCP-1), which induces fibrosis. Pulmonary fibroblast-derived MCP-1 may play a critical role in fibroblast proliferation and migration. Methods and results: Experiments using primary cultured adult human pulmonary fibroblasts (HPF-a) demonstrated the following results: 1) SiO{sub 2} treatment resulted in the rapid and sustained induction of MCP-1 as well as the elevation of the CC chemokine receptor type 2 (CCR2) protein levels; 2) pretreatment of HPF-a with RS-102895, a specific CCR2 inhibitor, abolished the SiO{sub 2}-induced increase in cell activation and migration in both 2D and 3D culture systems; and 3) RNA interference targeting CCR2 prevented the SiO{sub 2}-induced increase in cell migration. Conclusion: These data demonstrated that the up-regulation of pulmonary fibroblast-derived MCP-1 is involved in pulmonary fibroblast migration induced by SiO{sub 2}. CCR2 was also up-regulated in response to SiO{sub 2}, and this up-regulation facilitated the effect of MCP-1 on fibroblasts. Our study deciphered the link between fibroblast-derived MCP-1 and SiO{sub 2}-induced cell migration. This finding provides novel insight into the potential of MCP-1 in the development of novel therapeutic strategies for silicosis. - Highlights: • Role of pulmonary fibroblast-derived MCP-1 in experimental silicosis was studied. • SiO{sub 2} induced MCP-1 release from cultured human pulmonary fibroblast (HPF-a). • SiO{sub 2} directly activated HPF-a via the MCP-1/CCR2 pathway. • SiO{sub 2} increased HPF-a migration in both 2D and 3D
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Cascading walks model for human mobility patterns.
Han, Xiao-Pu; Wang, Xiang-Wen; Yan, Xiao-Yong; Wang, Bing-Hong
2015-01-01
Uncovering the mechanism behind the scaling laws and series of anomalies in human trajectories is of fundamental significance in understanding many spatio-temporal phenomena. Recently, several models, e.g. the explorations-returns model (Song et al., 2010) and the radiation model for intercity travels (Simini et al., 2012), have been proposed to study the origin of these anomalies and the prediction of human movements. However, an agent-based model that could reproduce most of empirical observations without priori is still lacking. In this paper, considering the empirical findings on the correlations of move-lengths and staying time in human trips, we propose a simple model which is mainly based on the cascading processes to capture the human mobility patterns. In this model, each long-range movement activates series of shorter movements that are organized by the law of localized explorations and preferential returns in prescribed region. Based on the numerical simulations and analytical studies, we show more than five statistical characters that are well consistent with the empirical observations, including several types of scaling anomalies and the ultraslow diffusion properties, implying the cascading processes associated with the localized exploration and preferential returns are indeed a key in the understanding of human mobility activities. Moreover, the model shows both of the diverse individual mobility and aggregated scaling displacements, bridging the micro and macro patterns in human mobility. In summary, our model successfully explains most of empirical findings and provides deeper understandings on the emergence of human mobility patterns.
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Migration and risk: net migration in marginal ecosystems and hazardous areas
International Nuclear Information System (INIS)
De Sherbinin, Alex; Levy, Marc; Adamo, Susana; MacManus, Kytt; Yetman, Greg; Mara, Valentina; Razafindrazay, Liana; Aichele, Cody; Pistolesi, Linda; Goodrich, Benjamin; Srebotnjak, Tanja
2012-01-01
The potential for altered ecosystems and extreme weather events in the context of climate change has raised questions concerning the role that migration plays in either increasing or reducing risks to society. Using modeled data on net migration over three decades from 1970 to 2000, we identify sensitive ecosystems and regions at high risk of climate hazards that have seen high levels of net in-migration and out-migration over the time period. This paper provides a literature review on migration related to ecosystems, briefly describes the methodology used to develop the estimates of net migration, then uses those data to describe the patterns of net migration for various ecosystems and high risk regions. The study finds that negative net migration generally occurs over large areas, reflecting its largely rural character, whereas areas of positive net migration are typically smaller, reflecting its largely urban character. The countries with largest population such as China and India tend to drive global results for all the ecosystems found in those countries. Results suggest that from 1970 to 2000, migrants in developing countries have tended to move out of marginal dryland and mountain ecosystems and out of drought-prone areas, and have moved towards coastal ecosystems and areas that are prone to floods and cyclones. For North America results are reversed for dryland and mountain ecosystems, which saw large net influxes of population in the period of record. Uncertainties and potential sources of error in these estimates are addressed. (letter)
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Janjusevic, Milijana; Greco, Stefania; Islam, Md Soriful; Castellucci, Clara; Ciavattini, Andrea; Toti, Paolo; Petraglia, Felice; Ciarmela, Pasquapina
2016-11-01
To investigate the presence of Raf kinase inhibitor protein (RKIP) in human myometrium and leiomyoma as well as to determine the effect of locostatin (RKIP inhibitor) on extracellular matrix (ECM) production, proliferation, and migration in human myometrial and leiomyoma cells. Laboratory study. Human myometrium and leiomyoma. Thirty premenopausal women who were admitted to the hospital for myomectomy or hysterectomy. Myometrial and leiomyoma tissues were used to investigate the localization and the expression level of RKIP through immunohistochemistry and Western blotting. Myometrial and leiomyoma cells were treated with locostatin (10 μM) to measure ECM expression by real-time polymerase chain reaction, GSK3β expression by Western blotting, cell migration by wound-healing assay, and cell proliferation by MTT assay and immunocytochemistry. The expression of RKIP in human myometrial and leiomyoma tissue; ECM components and GSK3β expression, migration, and proliferation in myometrial and leiomyoma cells. RKIP is expressed in human myometrial and leiomyoma tissue. Locostatin treatment resulted in the activation of the mitogen-activated protein kinase (MAPK) signal pathway (ERK phosphorylation), providing a powerful validation of our targeting protocol. Further, RKIP inhibition by locostatin reduces ECM components. Moreover, the inhibition of RKIP by locostatin impaired cell proliferation and migration in both leiomyoma and myometrial cells. Finally, locostatin treatment reduced GSK3β expression. Therefore, even if the activation of MAPK pathway should increase proliferation and migration, the destabilization of GSK3β leads to the reduction of proliferation and migration of myometrial and leiomyoma cells. Our results indicate that RKIP may be involved in leiomyoma pathophysiology. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.
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Migration in Afro-Brazilian rural communities: crossing demographic and genetic data.
Amorim, Carlos Eduardo G; Gontijo, Carolina C; Falcão-Alencar, Gabriel; Godinho, Neide M O; Toledo, Rafaela C P; Pedrosa, Maria Angélica F; Luizon, Marcelo R; Simões, Aguinaldo L; Klautau-Guimãres, Maria N; Oliveira, Silviene F
2011-08-01
Many studies have used genetic markers to understand global migration patterns of our species. However, there are only few studies of human migration on a local scale. We, therefore, researched migration dynamics in three Afro-Brazilian rural communities, using demographic data and ten Ancestry Informative Markers. In addition to the description of migration and marriage structures, we carried out genetic comparisons between the three populations, as well as between locals and migrants from each community. Genetic admixture analyses were conducted according to the gene-identity method, with Sub-Saharan Africans, Amerindians, and Europeans as parental populations. The three analyzed Afro-Brazilian rural communities consisted of 16% to 30% of migrants, most of them women. The age pyramid revealed a gap in the segment of men aged between 20 to 30 yrs. While endogamous marriages predominated, exogamous marriages were mainly patrilocal. Migration dynamics are apparently associated with matrimonial customs and other social practices of such communities. The impact of migration upon the populations' genetic composition was low but showed an increase in European alleles with a concomitant decrease in the Amerindian contribution. Admixture analysis evidenced a higher African contribution to the gene pool of the studied populations, followed by the contribution of Europeans and Amerindians, respectively.
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Selection or network effects? Migration flows into 27 OECD countries, 1990-2000
DEFF Research Database (Denmark)
Pedersen, Peder J.; Pytlikova, Mariola; Smith, Nina
Recent migration patterns show growing migration pressure and changing composition of immigrants in many Western countries. During the latest decade, an increasing proportion of the OECD immigrants have been from poor countries, where the educational level of the population is low. The migration ...... evidence that selection effects have had a major influence on the observed migration patterns until now. This may partly be explained by restrictive migration policies in many OECD countries which may have dampened the potential selection effects....
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Selection or Network Effects? Migration Flows into 27 OECD Countries, 1990-2000
DEFF Research Database (Denmark)
Pedersen, P.J.; Pytlikova, Mariola; Smith, Nina
Recent migration patterns show growing migration pressure and changing composition of immigrants in many Western countries. During the latest decade, an increasing proportion of the OECD immigrants have been from poor countries, where the educational level of the population is low. The migration ...... evidence that selection effects have had a major influence on the observed migration patterns until now. This may partly be explained by restrictive migration policies in many OECD countries which may have dampened the potential selection effects....
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Ye, Xiuqin; Hong, Wei; Hao, Binwei; Peng, Gongyong; Huang, Lingmei; Zhao, Zhuxiang; Zhou, Yumin; Zheng, Mengning; Li, Chenglong; Liang, Chunxiao; Yi, Erkang; Pu, Jinding; Li, Bing; Ran, Pixin
2018-03-02
The contribution of airway remodeling in chronic obstructive pulmonary disease (COPD) has been well documented, with airway smooth muscle cell proliferation and migration playing a role in the remodeling process. Here, we aimed to verify the effects of fine particulate matter (PM2.5) on human bronchial smooth muscle cell (HBSMC) migration and to explore the underlying signaling pathways. HBSMC apoptosis, proliferation and migration were measured using flow cytometry, cell counting and transwell migration assays, respectively. The role of the hedgehog pathway in cell migration was assessed by western blotting to measure the expression of Sonic hedgehog (Shh), Gli1 and Snail. Furthermore, siRNA was used to knock down Gli1 or Snail expression. PM2.5 induced HBSMC apoptosis in a dose-dependent manner, although certain concentrations of PM2.5 did not induce HBSMC proliferation or apoptosis. Interestingly, cell migration was stimulated by PM2.5 doses far below those that induced apoptosis. Additional experiments revealed that these PM2.5 doses enhanced the expression of Shh, Gli1 and Snail in HBSMCs. Furthermore, PM2.5-induced cell migration and protein expression were enhanced by recombinant Shh and attenuated by cyclopamine. Similar results were obtained by knocking down Gli1 or Snail. These findings suggest that PM2.5, which may exert its effects through the Shh signaling pathway, is necessary for the migration of HBSMCs. These data define a novel role for PM2.5 in airway remodeling in COPD.
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Capitalist development and internal migration in Nigeria.
Akor, R I; Mou, D
1986-12-01
The authors analyze internal migration trends in Nigeria by examining individual household strategies and how they have adapted to structural changes brought about by colonial rule and capitalist development. The first section of this article describes the structural changes that started the process of labor migration. The second section deals with post-independence industrialization and the consequent rural-urban migration. The final section analyzes the consequences of these migration patterns for urban growth and rural productivity.
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Autocrine stimulation of VEGFR-2 activates human leukemic cell growth and migration
Dias, Sergio; Hattori, Koichi; Zhu, Zhenping; Heissig, Beate; Choy, Margaret; Lane, William; Wu, Yan; Chadburn, Amy; Hyjek, Elizabeth; Gill, Muhammad; Hicklin, Daniel J.; Witte, Larry; Moore, M.A.S.; Rafii, Shahin
2000-01-01
Emerging data suggest that VEGF receptors are expressed by endothelial cells as well as hematopoietic stem cells. Therefore, we hypothesized that functional VEGF receptors may also be expressed in malignant counterparts of hematopoietic stem cells such as leukemias. We demonstrate that certain leukemias not only produce VEGF but also express functional VEGFR-2 in vivo and in vitro, resulting in the generation of an autocrine loop that may support leukemic cell survival and proliferation. Approximately 50% of freshly isolated leukemias expressed mRNA and protein for VEGFR-2. VEGF165 induced phosphorylation of VEGFR-2 and increased proliferation of leukemic cells, demonstrating these receptors were functional. VEGF165 also induced the expression of MMP-9 by leukemic cells and promoted their migration through reconstituted basement membrane. The neutralizing mAb IMC-1C11, specific to human VEGFR-2, inhibited leukemic cell survival in vitro and blocked VEGF165-mediated proliferation of leukemic cells and VEGF-induced leukemic cell migration. Xenotransplantation of primary leukemias and leukemic cell lines into immunocompromised nonobese diabetic mice resulted in significant elevation of human, but not murine, VEGF in plasma and death of inoculated mice within 3 weeks. Injection of IMC-1C11 inhibited proliferation of xenotransplanted human leukemias and significantly increased the survival of inoculated mice. Interruption of signaling by VEGFRs, particularly VEGFR-2, may provide a novel strategy for inhibiting leukemic cell proliferation. PMID:10953026
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Annual spatiotemporal migration schedules in three larger insectivorous birds
DEFF Research Database (Denmark)
Jacobsen, Lars Bo; Jensen, Niels Odder; Willemoes, Mikkel
2017-01-01
Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger ...
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IKKα regulates human keratinocyte migration through surveillance of the redox environment.
Lisse, Thomas S; Rieger, Sandra
2017-03-01
Although the functions of H 2 O 2 in epidermal wound repair are conserved throughout evolution, the underlying signaling mechanisms are largely unknown. In this study we used human keratinocytes (HEK001) to investigate H 2 O 2 -dependent wound repair mechanisms. Scratch wounding led to H 2 O 2 production in two or three cell layers at the wound margin within ∼30 min and subsequent cysteine modification of proteins via sulfenylation. Intriguingly, exogenous H 2 O 2 treatment resulted in preferential sulfenylation of keratinocytes that adopted a migratory phenotype and detached from neighboring cells, suggesting that one of the primary functions of H 2 O 2 is to stimulate signaling factors involved in cell migration. Based on previous findings that revealed epidermal growth factor receptor (EGFR) involvement in H 2 O 2 -dependent cell migration, we analyzed oxidation of a candidate upstream target, the inhibitor of κB kinase α (IKKα; encoded by CHUK ), as a mechanism of action. We show that IKKα is sulfenylated at a conserved cysteine residue in the kinase domain, which correlates with de-repression of EGF promoter activity and increased EGF expression. Thus, this indicates that IKKα promotes migration through dynamic interactions with the EGF promoter depending on the redox state within cells. © 2017. Published by The Company of Biologists Ltd.
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The mechanism for migration in Poland.
Rykiel, Z
1988-01-01
The author reviews neoclassical theories and models of migration. The mobility theory, which concerns the impact of local labor markets on migration, is discussed in the Polish context. A general model of the regional labor market and a multicausal model are developed to explain the patterns of internal migration. The period of a managed economy (1949-1980) is contrasted with the period since the implementation of a new economic system in 1983.
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Migration and first-time parenthood: Evidence from Kyrgyzstan
Directory of Open Access Journals (Sweden)
Gunnar Andersson
2007-12-01
Full Text Available This article investigates the reproductive behavior of young women and men in the post-Soviet Central Asian republic of Kyrgyzstan, focusing on the link between migration and fertility. We employ event-history techniques to retrospective data from the 'Marriage, Fertility, and Migration' survey conducted in Northern Kyrgyzstan in 2005 to study patterns in first-time parenthood. We demonstrate the extent to which internal migration is related to family formation and to the patterns of becoming a parent after resettlement. We gain deeper insights into demographic behavior by considering information on factors such as the geographical destination of migration and retrospectively stated motives for reported moves. In addition, our study reveals clear ethno-cultural differences in the timing of entry into parenthood in Kyrgyzstan.
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MANAGING MIGRATION: TURKISH PERSPECTIVE
Directory of Open Access Journals (Sweden)
İhsan GÜLAY
2018-04-01
Full Text Available Conducting migration studies is of vital importance to Turkey, a country which has been experiencing migration throughout history due to its “open doors policy”. The objective of this study is to evaluate the strategic management of migration in Turkey in order to deal with the issue of migration. The main focus of the study is Syrian migrants who sought refuge in Turkey due to the civil war that broke out in their country in April 2011. This study demonstrates the policies and processes followed by Turkey for Syrian migration flow in terms of the social acceptance and harmonisation of the migrants within a democratic environment. The study addresses some statistical facts and issues related to Syrian migration as it has become an integral part of daily life in Turkey. The study also reviews how human rights are protected in the migration process. The study will provide insights for developing sound strategic management policies for the migration issue.
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Distinct migration and contact dynamics of resting and IL-2-activated human natural killer cells
Directory of Open Access Journals (Sweden)
Per Erik Olofsson
2014-03-01
Full Text Available Natural killer (NK cells serve as one of the first lines of defense against viral infections and transformed cells. NK cell cytotoxicity is not dependent on antigen presentation by target cells, but is dependent on integration of activating and inhibitory signals triggered by receptor–ligand interactions formed at a tight intercellular contact between the NK and target cell, i.e. the immune synapse. We have studied the single-cell migration behavior and target-cell contact dynamics of resting and IL-2-activated human peripheral blood NK cells. Small populations of NK cells and target cells were confined in microwells and imaged by fluorescence microscopy for >8 h. Only the IL-2-activated population of NK cells showed efficient cytotoxicity against the human embryonic kidney (HEK 293T target cells. We found that although the average migration speeds were comparable, activated NK cells showed significantly more dynamic migration behavior, with more frequent transitions between periods of low and high motility. Resting NK cells formed fewer and weaker contacts with target cells, which manifested as shorter conjugation times and in many cases a complete lack of post-conjugation attachment to target cells. Activated NK cells were approximately twice as big as the resting cells, displayed a more migratory phenotype, and were more likely to employ motile scanning of the target cell surface during conjugation. Taken together, our experiments quantify, at the single-cell level, how activation by IL-2 leads to altered NK cell cytotoxicity, migration behavior and contact dynamics.
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Climate Shocks and Migration: An Agent-Based Modeling Approach
Entwisle, Barbara; Williams, Nathalie E.; Verdery, Ashton M.; Rindfuss, Ronald R.; Walsh, Stephen J.; Malanson, George P.; Mucha, Peter J.; Frizzelle, Brian G.; McDaniel, Philip M.; Yao, Xiaozheng; Heumann, Benjamin W.; Prasartkul, Pramote; Sawangdee, Yothin; Jampaklay, Aree
2016-01-01
This is a study of migration responses to climate shocks. We construct an agent-based model that incorporates dynamic linkages between demographic behaviors, such as migration, marriage, and births, and agriculture and land use, which depend on rainfall patterns. The rules and parameterization of our model are empirically derived from qualitative and quantitative analyses of a well-studied demographic field site, Nang Rong district, Northeast Thailand. With this model, we simulate patterns of migration under four weather regimes in a rice economy: 1) a reference, ‘normal’ scenario; 2) seven years of unusually wet weather; 3) seven years of unusually dry weather; and 4) seven years of extremely variable weather. Results show relatively small impacts on migration. Experiments with the model show that existing high migration rates and strong selection factors, which are unaffected by climate change, are likely responsible for the weak migration response. PMID:27594725
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Directory of Open Access Journals (Sweden)
Eun-Ryeong Hahm
Full Text Available D, L-Sulforaphane (SFN, a synthetic racemic analog of broccoli constituent L-sulforaphane, is a highly promising cancer chemopreventive agent with in vivo efficacy against chemically-induced as well as oncogene-driven cancer in preclinical rodent models. Cancer chemopreventive effect of SFN is characterized by G(2/M phase cell cycle arrest, apoptosis induction, and inhibition of cell migration and invasion. Moreover, SFN inhibits multiple oncogenic signaling pathways often hyperactive in human cancers, including nuclear factor-κB, Akt, signal transducer and activator of transcription 3, and androgen receptor. The present study was designed to determine the role of Notch signaling, which is constitutively active in many human cancers, in anticancer effects of SFN using prostate cancer cells as a model. Exposure of human prostate cancer cells (PC-3, LNCaP, and/or LNCaP-C4-2B to SFN as well as its naturally-occurring thio-, sulfinyl-, and sulfonyl-analogs resulted in cleavage (activation of Notch1, Notch2, and Notch4, which was accompanied by a decrease in levels of full-length Notch forms especially at the 16- and 24-hour time points. The SFN-mediated cleavage of Notch isoforms was associated with its transcriptional activation as evidenced by RBP-Jk-, HES-1A/B- and HEY-1 luciferase reporter assays. Migration of PC-3 and LNCaP cells was decreased significantly by RNA interference of Notch1 and Notch2, but not Notch4. Furthermore, SFN-mediated inhibition of PC-3 and LNCaP cell migration was only marginally affected by knockdown of Notch1 and Notch2. Strikingly, SFN administration to Transgenic Adenocarcinoma of Mouse Prostate transgenic mice failed to increase levels of cleaved Notch1, cleaved Notch2, and HES-1 proteins in vivo in prostatic intraepithelial neoplasia, well-differentiated carcinoma or poorly-differentiated prostate cancer lesions. These results indicate that Notch activation is largely dispensable for SFN-mediated inhibition of cell
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Lipopolysaccharide induces the migration of human dental pulp cells by up-regulating miR-146a.
Wang, Min-Ching; Hung, Pei-Shih; Tu, Hsi-Feng; Shih, Wen-Yu; Li, Wan-Chun; Chang, Kuo-Wei
2012-12-01
MicroRNAs are small noncoding RNAs that play crucial roles in regulating normal and pathologic functions. Bacterial lipopolysaccharide (LPS) is one of the key regulators of pulpal pathogenesis. This study investigated how LPS regulates microRNA expression and affects the phenotype of human dental pulp cells (DPCs). Primary DPCs were established and immortalized to achieve immortalized DPCs (I-DPCs). DPCs and I-DPCs were treated with LPS and examined to identify changes in microRNA expression, cell proliferation, and cell migration. Quantitative reverse-transcriptase polymerase chain reaction was used to detect changes in gene expression. Exogenous miR-146a expression was performed transfection with pre-mir-146a mimic. Knockdown of interleukin receptor-associated kinase (IRAK1) and tumor necrosis factor receptor-associated factor 6 (TRAF6) expression was performed by small interference oligonucleotide transfection. Western blot analysis was used to detect changes in the expression of the IRAK1 and TRAF6 proteins. The differentiation of DPCs was induced by osteogenic medium. I-DPCs had a higher level of human telomerase reverse transcriptase gene than the parental DPCs. Up-regulation of miR-146a expression and an increase in migration was induced by LPS treatment of DPCs and I-DPCs. Exogenous miR-146a expression increased the migration of DPCs and I-DPCs and down-regulated the expression of IRAK1 and TRAF6. Knockdown of IRAK1 and/or TRAF6 increased the migration of DPCs. The results suggested that LPS is able to increase the migration of DPCs by modulating the miR-146a-TRAF6/IRAK1 regulatory cascade. Copyright © 2012 American Association of Endodontists. All rights reserved.
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Inferring the rules of social interaction in migrating caribou.
Torney, Colin J; Lamont, Myles; Debell, Leon; Angohiatok, Ryan J; Leclerc, Lisa-Marie; Berdahl, Andrew M
2018-05-19
Social interactions are a significant factor that influence the decision-making of species ranging from humans to bacteria. In the context of animal migration, social interactions may lead to improved decision-making, greater ability to respond to environmental cues, and the cultural transmission of optimal routes. Despite their significance, the precise nature of social interactions in migrating species remains largely unknown. Here we deploy unmanned aerial systems to collect aerial footage of caribou as they undertake their migration from Victoria Island to mainland Canada. Through a Bayesian analysis of trajectories we reveal the fine-scale interaction rules of migrating caribou and show they are attracted to one another and copy directional choices of neighbours, but do not interact through clearly defined metric or topological interaction ranges. By explicitly considering the role of social information on movement decisions we construct a map of near neighbour influence that quantifies the nature of information flow in these herds. These results will inform more realistic, mechanism-based models of migration in caribou and other social ungulates, leading to better predictions of spatial use patterns and responses to changing environmental conditions. Moreover, we anticipate that the protocol we developed here will be broadly applicable to study social behaviour in a wide range of migratory and non-migratory taxa.This article is part of the theme issue 'Collective movement ecology'. © 2018 The Authors.
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Velocity-curvature patterns limit human-robot physical interaction.
Maurice, Pauline; Huber, Meghan E; Hogan, Neville; Sternad, Dagmar
2018-01-01
Physical human-robot collaboration is becoming more common, both in industrial and service robotics. Cooperative execution of a task requires intuitive and efficient interaction between both actors. For humans, this means being able to predict and adapt to robot movements. Given that natural human movement exhibits several robust features, we examined whether human-robot physical interaction is facilitated when these features are considered in robot control. The present study investigated how humans adapt to biological and non-biological velocity patterns in robot movements. Participants held the end-effector of a robot that traced an elliptic path with either biological (two-thirds power law) or non-biological velocity profiles. Participants were instructed to minimize the force applied on the robot end-effector. Results showed that the applied force was significantly lower when the robot moved with a biological velocity pattern. With extensive practice and enhanced feedback, participants were able to decrease their force when following a non-biological velocity pattern, but never reached forces below those obtained with the 2/3 power law profile. These results suggest that some robust features observed in natural human movements are also a strong preference in guided movements. Therefore, such features should be considered in human-robot physical collaboration.
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Diverging patterns with endogenous labor migration.
Reichlin, P; Rustichini, A
1998-05-05
"The standard neoclassical model cannot explain persistent migration flows and lack of cross-country convergence when capital and labor are mobile. Here we present a model where both phenomena may take place.... Our model is based on the Arrow-Romer approach to endogenous growth theory. We single out the importance of a (however weak) scale effect from the size of the workforce.... The main conclusion of this simple model is that lack of convergence, or even divergence, among countries is possible, even with perfect capital mobility and labor mobility." excerpt
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Hannon, Joseph Christopher; Kerry, Joseph P; Cruz-Romero, Malco; Azlin-Hasim, Shafrina; Morris, Michael; Cummins, Enda
2016-09-01
To examine the human exposure to a novel silver and copper nanoparticle (AgNP and CuNP)/polystyrene-polyethylene oxide block copolymer (PS-b-PEO) food packaging coating, the migration of Ag and Cu into 3% acetic acid (3% HAc) food simulant was assessed at 60 °C for 10 days. Significantly lower migration was observed for Ag (0.46 mg/kg food) compared to Cu (0.82 mg/kg food) measured by inductively coupled plasma - atomic emission spectrometry (ICP-AES). In addition, no distinct population of AgNPs or CuNPs were observed in 3% HAc by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The predicted human exposure to Ag and Cu was used to calculate a margin of exposure (MOE) for ionic species of Ag and Cu, which indicated the safe use of the food packaging in a hypothetical scenario (e.g. as fruit juice packaging). While migration exceeded regulatory limits, the calculated MOE suggests current migration limits may be conservative for specific nano-packaging applications. Copyright © 2016 Elsevier Ltd. All rights reserved.
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8000 years of caribou and human seasonal migration in the Canadian Barrenlands
Directory of Open Access Journals (Sweden)
Bryan C. Gordon
2005-05-01
Full Text Available Caribou (Rangifer tarandus are the common thread running through thousands of years of cultural evolution in northern mainland Canada. From the earliest Indian traditions, through the Pre-Dorset and Dene cultural evolution, up to historic times, the vast herds of migratory Barrenland caribou provided food, clothing and shelter. They determined the human cycle -- seasonal migrations, seasonal levels of fitness, and season of procreation. Caribou even permeated Dene mythology and supernatural beliefs. Within the Beverly caribou (R. t. groenlandicus range in the Canadian Barrenlands, investigation of 1002 archaeological sites points to long-term stability of human band and caribou herd interaction. Caribou bone and hunting tools occur in multiple levels, the earliest to 8000 years, based on 131 radiocarbon dates. Through time, specific hunting bands aligned with specific migratory barren-ground caribou herds. This relationship helps to explain observed archaeological and ethnological differences within different caribou ranges for these hunting bands. In general, biological evidence concurs with ethnographic and archaeological evidence. But short-term variations in migration routes between northern boreal forest, taiga and tundra may have followed changes in herd size and environment, e.g., unfavorable snow and ice conditions or forest fires. However, such influences were not discernible archaeologically.
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The CD157-integrin partnership controls transendothelial migration and adhesion of human monocytes.
Lo Buono, Nicola; Parrotta, Rossella; Morone, Simona; Bovino, Paola; Nacci, Giulia; Ortolan, Erika; Horenstein, Alberto L; Inzhutova, Alona; Ferrero, Enza; Funaro, Ada
2011-05-27
CD157, a member of the CD38 gene family, is an NAD-metabolizing ectoenzyme and a signaling molecule whose role in polarization, migration, and diapedesis of human granulocytes has been documented; however, the molecular events underpinning this role remain to be elucidated. This study focused on the role exerted by CD157 in monocyte migration across the endothelial lining and adhesion to extracellular matrix proteins. The results demonstrated that anti-CD157 antibodies block monocyte transmigration and adhesion to fibronectin and fibrinogen but that CD157 cross-linking is sufficient to overcome the block, suggesting an active signaling role for the molecule. Consistent with this is the observation that CD157 is prevalently located within the detergent-resistant membrane microdomains to which, upon clustering, it promotes the recruitment of β(1) and β(2) integrin, which, in turn, leads to the formation of a multimolecular complex favoring signal transduction. This functional cross-talk with integrins allows CD157 to act as a receptor despite its intrinsic structural inability to do so on its own. Intracellular signals mediated by CD157 rely on the integrin/Src/FAK (focal adhesion kinase) pathway, resulting in increased activity of the MAPK/ERK1/2 and the PI3K/Akt downstream signaling pathways, which are crucial in the control of monocyte transendothelial migration. Collectively, these findings indicate that CD157 acts as a molecular organizer of signaling-competent membrane microdomains and that it forms part of a larger molecular machine ruled by integrins. The CD157-integrin partnership provides optimal adhesion and transmigration of human monocytes.
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Glioma cells on the run – the migratory transcriptome of 10 human glioma cell lines
Directory of Open Access Journals (Sweden)
Holz David
2008-01-01
Full Text Available Abstract Background Glioblastoma multiforme (GBM is the most common primary intracranial tumor and despite recent advances in treatment regimens, prognosis for affected patients remains poor. Active cell migration and invasion of GBM cells ultimately lead to ubiquitous tumor recurrence and patient death. To further understand the genetic mechanisms underlying the ability of glioma cells to migrate, we compared the matched transcriptional profiles of migratory and stationary populations of human glioma cells. Using a monolayer radial migration assay, motile and stationary cell populations from seven human long term glioma cell lines and three primary GBM cultures were isolated and prepared for expression analysis. Results Gene expression signatures of stationary and migratory populations across all cell lines were identified using a pattern recognition approach that integrates a priori knowledge with expression data. Principal component analysis (PCA revealed two discriminating patterns between migrating and stationary glioma cells: i global down-regulation and ii global up-regulation profiles that were used in a proband-based rule function implemented in GABRIEL to find subsets of genes having similar expression patterns. Genes with up-regulation pattern in migrating glioma cells were found to be overexpressed in 75% of human GBM biopsy specimens compared to normal brain. A 22 gene signature capable of classifying glioma cultures based on their migration rate was developed. Fidelity of this discovery algorithm was assessed by validation of the invasion candidate gene, connective tissue growth factor (CTGF. siRNA mediated knockdown yielded reduced in vitro migration and ex vivo invasion; immunohistochemistry on glioma invasion tissue microarray confirmed up-regulation of CTGF in invasive glioma cells. Conclusion Gene expression profiling of migratory glioma cells induced to disperse in vitro affords discovery of genomic signatures; selected
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Timing of pre-nuptial migration and leap-frog patterns in Yellow ...
African Journals Online (AJOL)
nuptial migration period, in parts of the wintering grounds most distant from the breeding area. Birds breeding at the highest latitudes are the latest to depart on prenuptial migration, and so can take advantage of this surge by extending their ...
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Pattern Recognition as a Human Centered non-Euclidean Problem
Duin, R.P.W.
2010-01-01
Regularities in the world are human defined. Patterns in the observed phenomena are there because we define and recognize them as such. Automatic pattern recognition tries to bridge the gap between human judgment and measurements made by artificial sensors. This is done in two steps: representation
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The role of 'conservatism' in herring migrations
Corten, A.
2002-01-01
Herring (Clupea harengus) migrations tend to remain constant over periods of several years or even decades, despite environmental variation. When a migration pattern is changed, apparently in response to an environmental stimulus, the change in migratory behavior sometimes lasts longer than the
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Directory of Open Access Journals (Sweden)
Dannieli Firme Herbst
Full Text Available This research investigates local ecological knowledge of fishers in communities along a latitudinal gradient in the coast of the Santa Catarina State, regarding the life cycle of mullets Mugil liza (migration, feeding, and reproductive behavior. Our sampling encompassed eight Santa Catarina coastal cities (nine artisanal fishing sites and engaged 45 key informants (28- 86 years of age through semi-structured interviews from August/2011 to March/2012. This fish species feeds and grows in lagoon and estuarine systems, migrating to the sea for reproduction, and spawning. Fishers acknowledged the Patos Lagoon and the Plata River as the main source of mullet schools. Migration occurs from South to North and the routes vary according to climatic and oceanographic conditions (e.g., low temperatures, south winds, rainfall, currents, salinity. These conditions influence the abundance of mullets (and therefore fisheries success, their migration and stops in locations such as beaches, rocky shores, and islands. According to fishers, mullet spawning occurs throughout the coast of the Santa Catarina State and they feed in lagoons and riverine systems but also out at sea during migration. In conclusion, fishers possess a detailed knowledge about mullet life cycle and they identify intra and interannual variations in migration routes, a pattern that should be considered in managing the fishery.
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Relative estimation of the mineral ages using uranium migration
International Nuclear Information System (INIS)
Danis, A.
1990-01-01
Using the uranium fission track micro mapping technique the correlation between the age and uranium migration from inclusions was studied. It is shown that during geological time, as function of the mineral, its age and its uranium migration speed, the pattern of the track, clusters corresponding to the uranium inclusions got a typical feature. Thus for a bulk polished geological sample it is possible to establish an age succession of the constituent minerals as a function of the track cluster patterns. Also, it is shown that knowing the migration speed of the uranium in a mineral it is possible to estimate the age of this mineral by measuring the migration distance on the micro mapping. (Author)
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Migration patterns and movements of sandhill cranes wintering in central and southwestern Louisiana
King, Sammy L.; Pierce, Aaron R.; Hersey, Kent R.; Winstead, Nicholas; Hartup, Barry K.
2010-01-01
In this study we trapped wintering sandhill cranes (Grus canadensis) in Louisiana and fitted them with satellite transmitters to determine their migration routes. Four of the 6 sandhill cranes with validated locations and a terminus point used the Central Flyway for spring migration; 2 of these 4 (the only 2 for which we have data) also used the Central Flyway for fall migration. Two of the 6 birds used the Mississippi Flyway for spring migration. The results of this study suggest that reintroduced whooping cranes (G. americana) that intermix and migrate with sandhill cranes that winter in Louisiana may enter the Central Flyway. In addition, the Mississippi Flyway is a viable option to use as a migration route for whooping cranes if they are reintroduced in Louisiana.
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Buttari, Brigitta; Profumo, Elisabetta; Domenici, Giacomo; Tagliani, Angela; Ippoliti, Flora; Bonini, Sergio; Businaro, Rita; Elenkov, Ilia; Riganò, Rachele
2014-07-01
Neuropeptide Y (NPY), a major autonomic nervous system and stress mediator, is emerging as an important regulator of inflammation, implicated in autoimmunity, asthma, atherosclerosis, and cancer. Yet the role of NPY in regulating phenotype and functions of dendritic cells (DCs), the professional antigen-presenting cells, remains undefined. Here we investigated whether NPY could induce DCs to migrate, mature, and polarize naive T lymphocytes. We found that NPY induced a dose-dependent migration of human monocyte-derived immature DCs through the engagement of NPY Y1 receptor and the activation of ERK and p38 mitogen-activated protein kinases. NPY promoted DC adhesion to endothelial cells and transendothelial migration. It failed to induce phenotypic DC maturation, whereas it conferred a T helper 2 (Th2) polarizing profile to DCs through the up-regulation of interleukin (IL)-6 and IL-10 production. Thus, during an immune/inflammatory response NPY may exert proinflammatory effects through the recruitment of immature DCs, but it may exert antiinflammatory effects by promoting a Th2 polarization. Locally, at inflammatory sites, cell recruitment could be amplified in conditions of intense acute, chronic, or cold stress. Thus, altered or amplified signaling through the NPY-NPY-Y1 receptor-DC axis may have implications for the development of inflammatory conditions.-Buttari, B., Profumo, E., Domenici, G., Tagliani, A., Ippoliti, F., Bonini, S., Businaro, R., Elenkov, I., Riganò, R. Neuropeptide Y induces potent migration of human immature dendritic cells and promotes a Th2 polarization. © FASEB.
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Interregional migration in socialist countries: the case of China.
Wei, Y
1997-03-01
"This paper analyzes changing interregional migration in China and reveals that the recent eastward migration reverses patterns of migration under Mao. It finds that investment variables are more important than the conventional variables of income and job opportunities in determining China's recent interregional migration. It suggests that both state policy and the global force influence interregional migration, challenging the popular view that the socialist state is the only critical determinant. This paper also criticizes Mao's approach to interregional migration and discusses the impact of migration on development." excerpt
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Lea, James S E; Wetherbee, Bradley M; Queiroz, Nuno; Burnie, Neil; Aming, Choy; Sousa, Lara L; Mucientes, Gonzalo R; Humphries, Nicolas E; Harvey, Guy M; Sims, David W; Shivji, Mahmood S
2015-06-09
Long-distance movements of animals are an important driver of population spatial dynamics and determine the extent of overlap with area-focused human activities, such as fishing. Despite global concerns of declining shark populations, a major limitation in assessments of population trends or spatial management options is the lack of information on their long-term migratory behaviour. For a large marine predator, the tiger shark Galeocerdo cuvier, we show from individuals satellite-tracked for multiple years (up to 1101 days) that adult males undertake annually repeated, round-trip migrations of over 7,500 km in the northwest Atlantic. Notably, these migrations occurred between the highly disparate ecosystems of Caribbean coral reef regions in winter and high latitude oceanic areas in summer, with strong, repeated philopatry to specific overwintering insular habitat. Partial migration also occurred, with smaller, immature individuals displaying reduced migration propensity. Foraging may be a putative motivation for these oceanic migrations, with summer behaviour showing higher path tortuosity at the oceanic range extremes. The predictable migratory patterns and use of highly divergent ecosystems shown by male tiger sharks appear broadly similar to migrations seen in birds, reptiles and mammals, and highlight opportunities for dynamic spatial management and conservation measures of highly mobile sharks.
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Repeated, long-distance migrations by a philopatric predator targeting highly contrasting ecosystems
Lea, James S. E.; Wetherbee, Bradley M.; Queiroz, Nuno; Burnie, Neil; Aming, Choy; Sousa, Lara L.; Mucientes, Gonzalo R.; Humphries, Nicolas E.; Harvey, Guy M.; Sims, David W.; Shivji, Mahmood S.
2015-06-01
Long-distance movements of animals are an important driver of population spatial dynamics and determine the extent of overlap with area-focused human activities, such as fishing. Despite global concerns of declining shark populations, a major limitation in assessments of population trends or spatial management options is the lack of information on their long-term migratory behaviour. For a large marine predator, the tiger shark Galeocerdo cuvier, we show from individuals satellite-tracked for multiple years (up to 1101 days) that adult males undertake annually repeated, round-trip migrations of over 7,500 km in the northwest Atlantic. Notably, these migrations occurred between the highly disparate ecosystems of Caribbean coral reef regions in winter and high latitude oceanic areas in summer, with strong, repeated philopatry to specific overwintering insular habitat. Partial migration also occurred, with smaller, immature individuals displaying reduced migration propensity. Foraging may be a putative motivation for these oceanic migrations, with summer behaviour showing higher path tortuosity at the oceanic range extremes. The predictable migratory patterns and use of highly divergent ecosystems shown by male tiger sharks appear broadly similar to migrations seen in birds, reptiles and mammals, and highlight opportunities for dynamic spatial management and conservation measures of highly mobile sharks.
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Geographical pattern analysis of income migration in the United States.
Plane, D A
1999-01-01
"How one conceptualises the impacts of migration depends on whether one takes the viewpoint of aggregate area-level income change, of per capita change, or of longer-term (future earnings) change. Several empirical analytical measures are proposed in order to conceptualise the various income impacts of migration.... [A] decomposition procedure is developed for examining how the changes in per capita income of states reflect three different income differentials: those between (a) in-migrants and 'stayers', (b) out-migrants and 'stayers', and (c) in-migrants and out-migrants. Examination of these measures, and of typologies based on them, highlights how income migration significantly and differentially impacts upon U.S. states. The methods are illustrated here in the context of an important new American data source: the 1993-94 migrant income data released by the U.S. Internal Revenue Service." excerpt
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Jin, Aihong; Chen, Hao; Wang, Chaoqun; Tsang, Lai Ling; Jiang, Xiaohua; Cai, Zhiming; Chan, Hsiao Chang; Zhou, Xiaping
2014-06-01
To examine the expression of CD147 in 60 human endometriosis lesions and how CD147 regulates migration and apoptosis in human uterine epithelial (HESs) cells. Experimental clinical study and laboratory-based investigation. Hospital and academic research center. Sixty women with chocolate cysts and 16 control women without endometriosis. Human uterine epithelial cells were treated with anti-CD147 antibody. Real-time polymerase chain reaction for detecting CD147 expression in 60 human endometriosis lesions; migration assay and CellTiter 96 AQueous One Solution Cell Proliferation Assay (MTS) assay for cell functional investigation; Western blot for detecting protein levels; gelatin zymography for evaluating the activity of matrix metalloproteinase-2 (MMP-2) in cultured cells. Expression of CD147 was significantly higher in ectopic endometrial tissues from patients with endometriosis than in normal endometrial tissues. Interference with CD147 function led to decreased migration and cell viability in HESs cells. Surprisingly, MMP-2 expression and activity were not changed after treating HESs cells with anti-CD147 antibody. Further examination revealed that immunodepletion of CD147 induced apoptosis in HESs cells, leading to the activation of caspase 3 and poly(ADP-ribose) polymerase. The results of the present study suggest that abnormally high expression of CD147 in ovarian endometriosis lesions with enhanced cell survival (reduced apoptosis) and migration, in an MMP-2-independent manner, may underlie the progression of endometriosis in humans. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.
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Internal migration in the USSR: 1897-1926.
Leasure, J W; Lewis, R A
1967-06-01
The purpose of this study is to describe and to analyze internal migration in the USSR primarily by the use of data from the 1926 census of the USSR. The article is divided into two parts. The first is devoted to a description of the aggregate and regional migration patterns based on place-of-birth data. The second is an analysis of these migration patterns, primarily in terms of economic differentials by guberniya. Because only limited income data are available for the period around1926 and because other economic data are scarce or unusable owing to boundary changes, census data on labor force distribution, literacy, and urbanization are used as substitute variables to approximate income differences.Migrationis a complex phenomenon related to a host of factors. The present study does not presume fully to explain migration in the USSR, but it does attempt to isolate differences in income and to relate these to the internal migration that occurred during this period. As a result of processing and analyzing an extensive array of data, we have shown that differences in income, derived indirectly from a variety of data, are closely related to internal migration in the USSR in the period prior to the 1926 census. There were striking similarities in respect to internal migration between the period prior to the 1897 census and the period prior to the1926 census. The chief areas of out-migration and in-migration were roughly the same,and migrants in both periods moved primarily to areas of higher income.
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Wilkinson, Molly; Kane, Tara; Wang, Rongpin; Takahashi, Emi
2017-12-01
The thalamus plays an important role in signal relays in the brain, with thalamocortical (TC) neuronal pathways linked to various sensory/cognitive functions. In this study, we aimed to see fetal and postnatal development of the thalamus including neuronal migration to the thalamus and the emergence/maturation of the TC pathways. Pathways from/to the thalami of human postmortem fetuses and in vivo subjects ranging from newborns to adults with no neurological histories were studied using high angular resolution diffusion MR imaging (HARDI) tractography. Pathways likely linked to neuronal migration from the ventricular zone and ganglionic eminence (GE) to the thalami were both successfully detected. Between the ventricular zone and thalami, more tractography pathways were found in anterior compared with posterior regions, which was well in agreement with postnatal observations that the anterior TC segment had more tract count and volume than the posterior segment. Three different pathways likely linked to neuronal migration from the GE to the thalami were detected. No hemispheric asymmetry of the TC pathways was quantitatively observed during development. These results suggest that HARDI tractography is useful to identify multiple differential neuronal migration pathways in human brains, and regional differences in brain development in fetal ages persisted in postnatal development. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Directory of Open Access Journals (Sweden)
Tiziano Pramparo
2011-03-01
Full Text Available Heterozygous LIS1 mutations are the most common cause of human lissencephaly, a human neuronal migration defect, and DCX mutations are the most common cause of X-linked lissencephaly. LIS1 is part of a protein complex including NDEL1 and 14-3-3ε that regulates dynein motor function and microtubule dynamics, while DCX stabilizes microtubules and cooperates with LIS1 during neuronal migration and neurogenesis. Targeted gene mutations of Lis1, Dcx, Ywhae (coding for 14-3-3ε, and Ndel1 lead to neuronal migration defects in mouse and provide models of human lissencephaly, as well as aid the study of related neuro-developmental diseases. Here we investigated the developing brain of these four mutants and wild-type mice using expression microarrays, bioinformatic analyses, and in vivo/in vitro experiments to address whether mutations in different members of the LIS1 neuronal migration complex lead to similar and/or distinct global gene expression alterations. Consistent with the overall successful development of the mutant brains, unsupervised clustering and co-expression analysis suggested that cell cycle and synaptogenesis genes are similarly expressed and co-regulated in WT and mutant brains in a time-dependent fashion. By contrast, focused co-expression analysis in the Lis1 and Ndel1 mutants uncovered substantial differences in the correlation among pathways. Differential expression analysis revealed that cell cycle, cell adhesion, and cytoskeleton organization pathways are commonly altered in all mutants, while synaptogenesis, cell morphology, and inflammation/immune response are specifically altered in one or more mutants. We found several commonly dysregulated genes located within pathogenic deletion/duplication regions, which represent novel candidates of human mental retardation and neurocognitive disabilities. Our analysis suggests that gene expression and pathway analysis in mouse models of a similar disorder or within a common pathway can
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Palaearctic-African Bird Migration
DEFF Research Database (Denmark)
Iwajomo, Soladoye Babatola
Bird migration has attracted a lot of interests over past centuries and the methods used for studying this phenomenon has greatly improved in terms of availability, dimension, scale and precision. In spite of the advancements, relatively more is known about the spring migration of trans-Saharan m......Bird migration has attracted a lot of interests over past centuries and the methods used for studying this phenomenon has greatly improved in terms of availability, dimension, scale and precision. In spite of the advancements, relatively more is known about the spring migration of trans...... of birds from Europe to Africa and opens up the possibility of studying intra-African migration. I have used long-term, standardized autumn ringing data from southeast Sweden to investigate patterns in biometrics, phenology and population trends as inferred from annual trapping totals. In addition, I...... in the population of the species. The papers show that adult and juvenile birds can use different migration strategies depending on time of season and prevailing conditions. Also, the fuel loads of some individuals were theoretically sufficient for a direct flight to important goal area, but whether they do so...
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Directory of Open Access Journals (Sweden)
Dirk Hoerder
2012-05-01
Full Text Available Both migrations and attitudes towards them have deep historical roots. To pronounce the present migration and the economic crisis triggered by derivative bankers in the fall of 2008 as “new without historical precedent” overlooks the impact of patterns of the past on the present and prevents an understanding being reached of continuities and comparisons. It is not migrants who are “uprooted”, as some would have it, but historical memory is deliberately being uprooted. This essay starts by addressing the multiple problems of present-day debates about migration and historicising the perspectives. It critiques the anti-immigrant ascriptions, labels and ideologies. It goes on to present the data and discuss the geographies of migrant trajectories in the context of translocal, transregional, transnational and global connectivity. An integrative Transcultural Societal Studies approach will be proposed. The essay will then deal with migrant agency, that is the actions of migrants, criticising “victimization” approaches and argue that Otherness is a resource as well as a framework for exploitation. Remittances will serve as an example of the intersection between migrant agency and states’ needs. The conclusion will briefly place the present in the context of global inequalities, of the economic aspect and of anti-immigrantism, as well as the ideological national-essentialist aspect.
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Twilight vertical migrations of zooplankton in a Chilean fjord
Valle-Levinson, Arnoldo; Castro, Leonardo; Cáceres, Mario; Pizarro, Oscar
2014-12-01
Time series of acoustic backscatter and vertical velocity profiles were obtained at three sites along a Chilean fjord with the purpose of determining dominant structures of vertical migrations of the sound scattering layer. Ancillary data obtained with stratified net samples indicated that the sound scattering layer may have been dominated by euphausiids and decapods. Therefore, distributions of acoustic backscatter anomalies and vertical velocities were attributed to vertical migrations of predominantly these organisms. Migration patterns were dominated by twilight excursions in which organisms swam toward the water surface at sunset, spent 100 m). This migration strategy can also be termed 'semidiel migration' as two double excursions were linked to light levels. The reasons for this twilight migration remain uncertain. But it is possible that the up and down motion around sunset was related to predation avoidance, hunger-satiation state, ontogeny, seaward transport evasion, or reaction to the environmental shock from the pycnocline, or a combination of all or some of them. In contrast, the sunrise double excursion was probably linked to feeding requirements by organisms that need to spend the day at great depth with no food available. This study demonstrated the existence of semidiel patterns throughout the fjord and through prolonged periods. In addition, identification of this pattern by acoustic backscatter was complemented by direct vertical velocity measurements. It is proposed that twilight vertical migration is a common strategy in Chilean fjords.
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The CD157-Integrin Partnership Controls Transendothelial Migration and Adhesion of Human Monocytes*
Lo Buono, Nicola; Parrotta, Rossella; Morone, Simona; Bovino, Paola; Nacci, Giulia; Ortolan, Erika; Horenstein, Alberto L.; Inzhutova, Alona; Ferrero, Enza; Funaro, Ada
2011-01-01
CD157, a member of the CD38 gene family, is an NAD-metabolizing ectoenzyme and a signaling molecule whose role in polarization, migration, and diapedesis of human granulocytes has been documented; however, the molecular events underpinning this role remain to be elucidated. This study focused on the role exerted by CD157 in monocyte migration across the endothelial lining and adhesion to extracellular matrix proteins. The results demonstrated that anti-CD157 antibodies block monocyte transmigration and adhesion to fibronectin and fibrinogen but that CD157 cross-linking is sufficient to overcome the block, suggesting an active signaling role for the molecule. Consistent with this is the observation that CD157 is prevalently located within the detergent-resistant membrane microdomains to which, upon clustering, it promotes the recruitment of β1 and β2 integrin, which, in turn, leads to the formation of a multimolecular complex favoring signal transduction. This functional cross-talk with integrins allows CD157 to act as a receptor despite its intrinsic structural inability to do so on its own. Intracellular signals mediated by CD157 rely on the integrin/Src/FAK (focal adhesion kinase) pathway, resulting in increased activity of the MAPK/ERK1/2 and the PI3K/Akt downstream signaling pathways, which are crucial in the control of monocyte transendothelial migration. Collectively, these findings indicate that CD157 acts as a molecular organizer of signaling-competent membrane microdomains and that it forms part of a larger molecular machine ruled by integrins. The CD157-integrin partnership provides optimal adhesion and transmigration of human monocytes. PMID:21478153
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Fisher, Matthew C.; Koenig, Gina L.; White, Thomas J.; San-Blas, Gioconda; Negroni, Ricardo; Alvarez, Isidro Gutiérrez; Wanke, Bodo; Taylor, John W.
2001-01-01
Long-distance population dispersal leaves its characteristic signature in genomes, namely, reduced diversity and increased linkage between genetic markers. This signature enables historical patterns of range expansion to be traced. Herein, we use microsatellite loci from the human pathogen Coccidioides immitis to show that genetic diversity in this fungus is geographically partitioned throughout North America. In contrast, analyses of South American C. immitis show that this population is genetically depauperate and was founded from a single North American population centered in Texas. Variances of allele distributions show that South American C. immitis have undergone rapid population growth, consistent with an epidemic increase in postcolonization population size. Herein, we estimate the introduction into South America to have occurred within the last 9,000–140,000 years. This range increase parallels that of Homo sapiens. Because of known associations between Amerindians and this fungus, we suggest that the colonization of South America by C. immitis represents a relatively recent and rapid codispersal of a host and its pathogen. PMID:11287648
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Lesslie, D P; Summy, J M; Parikh, N U; Fan, F; Trevino, J G; Sawyer, T K; Metcalf, C A; Shakespeare, W C; Hicklin, D J; Ellis, L M; Gallick, G E
2006-01-01
Vascular endothelial growth factor (VEGF) is the predominant pro-angiogenic cytokine in human malignancy, and its expression correlates with disease recurrence and poor outcomes in patients with colorectal cancer. Recently, expression of vascular endothelial growth factor receptors (VEGFRs) has been observed on tumours of epithelial origin, including those arising in the colon, but the molecular mechanisms governing potential VEGF-driven biologic functioning in these tumours are not well characterised. In this report, we investigated the role of Src family kinases (SFKs) in VEGF-mediated signalling in human colorectal carcinoma (CRC) cell lines. Vascular endothelial growth factor specifically activated SFKs in HT29 and KM12L4 CRC cell lines. Further, VEGF stimulation resulted in enhanced cellular migration, which was effectively blocked by pharmacologic inhibition of VEGFR-1 or Src kinase. Correspondingly, migration studies using siRNA clones with reduced Src expression confirmed the requirement for Src in VEGF-induced migration in these cells. Furthermore, VEGF treatment enhanced VEGFR-1/SFK complex formation and increased tyrosine phosphorylation of focal adhesion kinase, p130 cas and paxillin. Finally, we demonstrate that VEGF-induced migration is not due, at least in part, to VEGF acting as a mitogen. These results suggest that VEGFR-1 promotes migration of tumour cells through a Src-dependent pathway linked to activation of focal adhesion components that regulate this process. PMID:16685275
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International Nuclear Information System (INIS)
Khalil, A.A.; Jameson, M.J.; Broaddus, W.C.; Lin, P.S.; Chung, T.D.
2013-01-01
It has been suggested that continued tobacco use during radiation therapy contributes to maintenance of neoplastic growth despite treatment with radiation. Nicotine is a cigarette component that is an established risk factor for many diseases, neoplastic and otherwise. The hypothesis of this work is that nicotine promotes the proliferation, migration, and radioresistance of human malignant glioma cells. The effect of nicotine on cellular proliferation, migration, signaling, and radiation sensitivity were evaluated for malignant glioma U87 and GBM12 cells by use of the AlamarBlue, scratch healing, and clonogenic survival assays. Signal transduction was assessed by immunoblotting for activated EGFR, extracellular regulated kinase (ERK), and AKT. At concentrations comparable with those found in chronic smokers, nicotine induced malignant glioma cell migration, growth, colony formation, and radioresistance. Nicotine increased phosphorylation of EGFR tyr992 , AKT ser473 , and ERK. These molecular effects were reduced by pharmacological inhibitors of EGFR, PI3K, and MEK. It was therefore concluded that nicotine stimulates the malignant behavior of glioma cells in vitro by activation of the EGFR and downstream AKT and ERK pathways. (author)
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Out-of-Africa migration and Neolithic coexpansion of Mycobacterium tuberculosis with modern humans.
Comas, Iñaki; Coscolla, Mireia; Luo, Tao; Borrell, Sonia; Holt, Kathryn E; Kato-Maeda, Midori; Parkhill, Julian; Malla, Bijaya; Berg, Stefan; Thwaites, Guy; Yeboah-Manu, Dorothy; Bothamley, Graham; Mei, Jian; Wei, Lanhai; Bentley, Stephen; Harris, Simon R; Niemann, Stefan; Diel, Roland; Aseffa, Abraham; Gao, Qian; Young, Douglas; Gagneux, Sebastien
2013-10-01
Tuberculosis caused 20% of all human deaths in the Western world between the seventeenth and nineteenth centuries and remains a cause of high mortality in developing countries. In analogy to other crowd diseases, the origin of human tuberculosis has been associated with the Neolithic Demographic Transition, but recent studies point to a much earlier origin. We analyzed the whole genomes of 259 M. tuberculosis complex (MTBC) strains and used this data set to characterize global diversity and to reconstruct the evolutionary history of this pathogen. Coalescent analyses indicate that MTBC emerged about 70,000 years ago, accompanied migrations of anatomically modern humans out of Africa and expanded as a consequence of increases in human population density during the Neolithic period. This long coevolutionary history is consistent with MTBC displaying characteristics indicative of adaptation to both low and high host densities.
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Energy Technology Data Exchange (ETDEWEB)
Shi, Zi-xuan [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Rao, Wei [Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Huan [Department of Dermatology, Tangdu Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Nan-ding [Department of Cardiology, Xi' an Traditional Chinese Medicine Hospital, Xi' an, 710032 (China); Si, Jing-Wen; Zhao, Jiao; Li, Jun-chang [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Zong-ren, E-mail: zongren@fmmu.edu.cn [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China)
2015-02-13
Glioblastoma is the most common brain tumor and is characterized with robust invasion and migration potential resulting in poor prognosis. Previous investigations have demonstrated that modeled microgravity (MMG) could decline the cell proliferation and attenuate the metastasis potential in several cell lines. In this study, we studied the effects of MMG on the invasion and migration potentials of glioblastoma in human glioblastoma U87 cells. We found that MMG stimulation significantly attenuated the invasion and migration potentials, decreased thapsigargin (TG) induced store-operated calcium entry (SOCE) and downregulated the expression of Orai1 in U87 cells. Inhibition of SOCE by 2-APB or stromal interaction molecule 1 (STIM1) downregulation both mimicked the effects of MMG on the invasion and migration potentials in U87 cells. Furthermore, upregulation of Orai1 significantly weakened the effects of MMG on the invasion and migration potentials in U87 cells. Therefore, these findings indicated that MMG stimulation inhibited the invasion and migration potentials of U87 cells by downregulating the expression of Orai1 and sequentially decreasing the SOCE, suggesting that MMG might be a new potential therapeutic strategy in glioblastoma treatment in the future. - Highlights: • Modeled microgravity (MMG) suppressed migration and invasion in U87 cells. • MMG downregulated the SOCE and the expression of Orai1. • SOCE inhibition mimicked the effects of MMG on migration and invasion potentials. • Restoration of SOCE diminished the effects of MMG on migration and invasion.
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International Nuclear Information System (INIS)
Shi, Zi-xuan; Rao, Wei; Wang, Huan; Wang, Nan-ding; Si, Jing-Wen; Zhao, Jiao; Li, Jun-chang; Wang, Zong-ren
2015-01-01
Glioblastoma is the most common brain tumor and is characterized with robust invasion and migration potential resulting in poor prognosis. Previous investigations have demonstrated that modeled microgravity (MMG) could decline the cell proliferation and attenuate the metastasis potential in several cell lines. In this study, we studied the effects of MMG on the invasion and migration potentials of glioblastoma in human glioblastoma U87 cells. We found that MMG stimulation significantly attenuated the invasion and migration potentials, decreased thapsigargin (TG) induced store-operated calcium entry (SOCE) and downregulated the expression of Orai1 in U87 cells. Inhibition of SOCE by 2-APB or stromal interaction molecule 1 (STIM1) downregulation both mimicked the effects of MMG on the invasion and migration potentials in U87 cells. Furthermore, upregulation of Orai1 significantly weakened the effects of MMG on the invasion and migration potentials in U87 cells. Therefore, these findings indicated that MMG stimulation inhibited the invasion and migration potentials of U87 cells by downregulating the expression of Orai1 and sequentially decreasing the SOCE, suggesting that MMG might be a new potential therapeutic strategy in glioblastoma treatment in the future. - Highlights: • Modeled microgravity (MMG) suppressed migration and invasion in U87 cells. • MMG downregulated the SOCE and the expression of Orai1. • SOCE inhibition mimicked the effects of MMG on migration and invasion potentials. • Restoration of SOCE diminished the effects of MMG on migration and invasion
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Hasaneen, Nadia A; Zucker, Stanley; Cao, Jian; Chiarelli, Christian; Panettieri, Reynold A; Foda, Hussein D
2005-09-01
Airway smooth muscle (ASM) proliferation and migration are major components of airway remodeling in asthma. Asthmatic airways are exposed to mechanical strain, which contributes to their remodeling. Matrix metalloproteinase (MMP) plays an important role in remodeling. In the present study, we examined if the mechanical strain of human ASM (HASM) cells contributes to their proliferation and migration and the role of MMPs in this process. HASM were exposed to mechanical strain using the FlexCell system. HASM cell proliferation, migration and MMP release, activation, and expression were assessed. Our results show that cyclic strain increased the proliferation and migration of HASM; cyclic strain increased release and activation of MMP-1, -2, and -3 and membrane type 1-MMP; MMP release was preceded by an increase in extracellular MMP inducer; Prinomastat [a MMP inhibitor (MMPI)] significantly decreased cyclic strain-induced proliferation and migration of HASM; and the strain-induced increase in the release of MMPs was accompanied by an increase in tenascin-C release. In conclusion, cyclic mechanical strain plays an important role in HASM cell proliferation and migration. This increase in proliferation and migration is through an increase in MMP release and activation. Pharmacological MMPIs should be considered in the pursuit of therapeutic options for airway remodeling in asthma.
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Gabriël, S; Johansen, M V; Pozio, E; Smit, G S A; Devleesschauwer, B; Allepuz, A; Papadopoulos, E; van der Giessen, J; Dorny, P
2015-09-30
Taenia solium taeniasis/cysticercosis is a neglected zoonotic disease complex occurring primarily in developing countries. Though claimed eradicated from the European Union (EU), an increasing number of human neurocysticercosis cases is being detected. Risk factors such as human migration and movement of pigs/pork, as well as the increasing trend in pig rearing with outside access are discussed in this review. The entry of a tapeworm carrier into the EU seems a lot more plausible than the import of infected pork. The establishment of local transmission in the EU is presently very unlikely. However, considering the potential changes in risk factors, such as the increasing trend in pig farming with outdoor access, the increasing human migration from endemic areas into the EU, this situation might change, warranting the establishment of an early warning system, which should include disease notification of taeniasis/cysticercosis both in human and animal hosts. As currently human-to-human transmission is the highest risk, prevention strategies should focus on the early detection and treatment of tapeworm carriers, and should be designed in a concerted way, across the EU and across the different sectors. Copyright © 2015 Elsevier B.V. All rights reserved.
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Directory of Open Access Journals (Sweden)
Susanne Eva Tanner
2015-10-01
Full Text Available Connectivity is a critical property of marine fish populations as it drives population replenishment, determines colonization patterns and the resilience of populations to harvest. Understanding connectivity patterns is particularly important in species that present ontogenetic migrations and segregated habitat use during their life history, such as marine species with estuarine nursery areas. Albeit challenging, fish movement can be estimated and quantified using different methodologies depending on the life history stages of interest (e.g. biophysical modelling, otolith chemistry, genetic markers. Relative contributions from estuarine nursery areas to the adult coastal populations were determined using otolith elemental composition and maximum likelihood estimation for four commercially important species (Dicentrarchus labrax, Plathichtys flesus, Solea senegalensis and Solea solea and showed high interannual variability. Here, the effects of abiotic and biotic factors on the observed variability in connectivity rates and extent between estuarine juvenile and coastal adult subpopulations are investigated using generalized linear models (GLM and generalized mixed models (GMM. Abiotic factors impacting both larval and juvenile life history stages are included in the models (e.g. wind force and direction, NAO, water temperature while biotic factors relative to the estuarine residency of juvenile fish are evaluated (e.g. juvenile density, food availability. Factors contributing most to the observed variability in connectivity rates are singled out and compared among species. General trends are identified and results area discussed in the general context of identifying potential management frameworks applicable to different life stages and which may prove useful for ontogenetically migrating species.
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Enterovirus Migration Patterns between France and Tunisia.
Othman, Ines; Mirand, Audrey; Slama, Ichrak; Mastouri, Maha; Peigue-Lafeuille, Hélène; Aouni, Mahjoub; Bailly, Jean-Luc
2015-01-01
The enterovirus (EV) types echovirus (E-) 5, E-9, and E-18, and coxsackievirus (CV-) A9 are infrequently reported in human diseases and their epidemiologic features are poorly defined. Virus transmission patterns between countries have been estimated with phylogenetic data derived from the 1D/VP1 and 3CD gene sequences of a sample of 74 strains obtained in France (2000-2012) and Tunisia (2011-2013) and from the publicly available sequences. The EV types (E-5, E-9, and E-18) exhibited a lower worldwide genetic diversity (respective number of genogroups: 4, 5, and 3) in comparison to CV-A9 (n = 10). The phylogenetic trees estimated with both 1D/VP1 and 3CD sequence data showed variations in the number of co-circulating lineages over the last 20 years among the four EV types. Despite the low number of genogroups in E-18, the virus exhibited the highest number of recombinant 3CD lineages (n = 10) versus 4 (E-5) to 8 (E-9). The phylogenies provided evidence of multiple transportation events between France and Tunisia involving E-5, E-9, E-18, and CV-A9 strains. Virus spread events between France and 17 other countries in five continents had high probabilities of occurrence as those between Tunisia and two European countries other than France. All transportation events were supported by BF values > 10. Inferring the source of virus transmission from phylogenetic data may provide insights into the patterns of sporadic and epidemic diseases caused by EVs.
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Fehlauer, Fabian; Muench, Martina; Rades, Dirk; Stalpers, Lukas J. A.; Leenstra, Sieger; van der Valk, Paul; Slotman, Ben; Smid, Ernst J.; Sminia, Peter
2005-01-01
Investigation of cell migration and proliferation of human glioma cell line spheroids (CLS) and evaluation of morphology, apoptosis, and immunohistochemical expression of MIB-1, p53, and p21 of organotypic muticellular spheroids (OMS) following cisplatin (CDDP) and irradiation (RT). Spheroids of the
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Blachford, Dongyan Ru; Zhang, Bailing
2014-01-01
This article examines the dynamics of brain circulation through a historical review of the debates over international migration of human capital and a case study on Chinese-Canadian academics. Interviews with 22 Chinese-Canadian professors who originally came from China provide rich data regarding the possibilities and problems of the contemporary…
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Rural migration in Nevada: Lincoln County
International Nuclear Information System (INIS)
Soden, D.L.; Carns, D.E.; Mosser, D.; Conary, J.S.; Ansell, J.P.
1993-01-01
The principal objective of this project was to develop insight into the scope of migration of working age Nevadans out of their county of birth; including the collection of data on their skill levels, desire to out or in-migrate, interactions between families of migratory persons, and the impact that the proposed high-level nuclear waste repository at Yucca mountain might have on their individual, and collective, decisions to migrate and return. The initial phase of this project reported here was conducted in 1992 and 1993 in Lincoln County, Nevada, one of the counties designated as ''affected'' by the proposed repository program. The findings suggest that a serious out-migration problem in Lincoln County, and that the Yucca mountain project will likely affect decisions relating to migration patterns in the future
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Directory of Open Access Journals (Sweden)
Ievdokymov V.V.
2017-06-01
Full Text Available Numerous humanitarian, socio-economic and environmental problems caused by the worldwide refugees’ migration lead to aggravation of the political debate on these issues. A geo-economic transformation in the world, which consists of multipolar geo-economic space formation, causing the need to managing migration movements of refugees between countries and regions around the world. This is associated with the importance of consideration of refugees’ migration as a factor of human resources redistribution in the world and the need to develop the regional migration policies for eliminating the negative effects of such migration. The research aimed to studying the current trends, preconditions and problems of refugees’ migration as a special category of migrants from countries developing in conflict and in post-conflict conditions. Found that there are military conflicts in all the countries that are leaders by refugees’ origin. In addition, the indicators of refugees’ pressure on socio-demographic, territorial and economic systems of host countries have been described, as well as analysis of the main refugees’ destination countries indicators has been carried out. This analysis has been done in interconnection with the surveyed countries rank in the Fragile States Index 2017.
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Directory of Open Access Journals (Sweden)
Andrew Mamalis
Full Text Available Skin fibrosis is a significant medical problem that leads to a functional, aesthetic, and psychosocial impact on quality-of-life. Light-emitting diode-generated 633-nm red light (LED-RL is part of the visible light spectrum that is not known to cause DNA damage and is considered a safe, non-invasive, inexpensive, and portable potential alternative to ultraviolet phototherapy that may change the treatment paradigm of fibrotic skin disease.The goal of our study was to investigate the how reactive oxygen species (ROS free radicals generated by high fluence LED-RL inhibit the migration of skin fibroblasts, the main cell type involved in skin fibrosis. Fibroblast migration speed is increased in skin fibrosis, and we studied cellular migration speed of cultured human skin fibroblasts as a surrogate measure of high fluence LED-RL effect on fibroblast function. To ascertain the inhibitory role of LED-RL generated ROS on migration speed, we hypothesized that resveratrol, a potent antioxidant, could prevent the photoinhibitory effects of high fluence LED-RL on fibroblast migration speed.High fluence LED-RL generated ROS were measured by flow cytometry analysis using dihydrorhodamine (DHR. For purposes of comparison, we assessed the effects of ROS generated by hydrogen peroxide (H2O2 on fibroblast migration speed and the ability of resveratrol, a well known antioxidant, to prevent LED-RL and H2O2 generated ROS-associated changes in fibroblast migration speed. To determine whether resveratrol could prevent the high fluence LED-RL ROS-mediated photoinhibition of human skin fibroblast migration, treated cells were incubated with resveratrol at concentrations of 0.0001% and 0.001% for 24 hours, irradiated with high fluences LED-RL of 480, 640, and 800 J/cm2.High fluence LED-RL increases intracellular fibroblast ROS and decreases fibroblast migration speed. LED-RL at 480, 640 and 800 J/cm2 increased ROS levels to 132.8%, 151.0%, and 158.4% relative to matched
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International Nuclear Information System (INIS)
Varley, Claire; Hill, Gemma; Pellegrin, Stephanie; Shaw, Nicola J.; Selby, Peter J.; Trejdosiewicz, Ludwik K.; Southgate, Jennifer
2005-01-01
Regeneration of the urothelium is rapid and effective in order to maintain a barrier to urine following tissue injury. Whereas normal human urothelial (NHU) cells are mitotically quiescent and G0 arrested in situ, they rapidly enter the cell cycle upon seeding in primary culture and show reversible growth arrest at confluency. We have used this as a model to investigate the role of EGF receptor signaling in urothelial regeneration and wound-healing. Transcripts for HER-1, HER-2, and HER-3 were expressed by quiescent human urothelium in situ. Expression of HER-1 was upregulated in proliferating cultures, whereas HER-2 and HER-3 were more associated with a growth-arrested phenotype. NHU cells could be propagated in the absence of exogenous EGF, but autocrine signaling through HER-1 via the MAPK and PI3-kinase pathways was essential for proliferation and migration during urothelial wound repair. HB-EGF was expressed by urothelium in situ and HB-EGF, epiregulin, TGF-α, and amphiregulin were expressed by proliferating NHU cells. Urothelial wound repair in vitro was attenuated by neutralizing antibodies against HER-1 ligands, particularly amphiregulin. By contrast, the same ligands applied exogenously promoted migration, but inhibited proliferation, implying that HER-1 ligands provoke differential effects in NHU cells depending upon whether they are presented as soluble or juxtacrine ligands. We conclude that proliferation and migration during wound healing in NHU cells are mediated through an EGFR autocrine signalling loop and our results implicate amphiregulin as a key mediator
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Ke, Yang; Bao, Tianhao; Wu, Xuesong; Tang, Haoran; Wang, Yan; Ge, Jiayun; Fu, Bimang; Meng, Xu; Chen, Li; Zhang, Cheng; Tan, Yuqi; Chen, Haotian; Guo, Zhitang; Ni, Fan; Lei, Xuefen; Shi, Zhitian; Wei, Dong; Wang, Lin
2017-01-29
Scutellarin is an active flavone from Erigeron breviscapine (vant) Hand Mass. This study aimed to investigate the potential role of scutellarin in migration and invasion of human hepatocellular carcinoma (HCC) cells and its possible mechanism. In comparison with the vehicle-treated controls, treatment with scutellarin (50 mg/kg/day) for 35 days significantly mitigated the lung and intrahepatic metastasis of HCC tumors in vivo. Scutellarin treatment significantly reduced HepG2 cell viability in a dose-dependent manner, and inhibited migration and invasion of HCC cells in vitro. Scutellarin treatment significantly reduced STAT3 and Girders of actin filaments (Girdin) expression, STAT3 and Akt phosphorylation in HCC cells. Introduction of STAT3 overexpression restored the scutellarin-downregulated Girdin expression, Akt activation, migration and invasion of HCC cells. Furthermore, induction of Girdin overexpression completely abrogated the inhibition of scutellarin on the Akt phosphorylation, migration and invasion of HCC cells. Scutellarin can inhibit HCC cell metastasis in vivo, and migration and invasion in vitro by down-regulating the STAT3/Girdin/Akt signaling. Copyright © 2016 Elsevier Inc. All rights reserved.
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Benefits of the destinations, not costs of the journeys, shape partial migration patterns
Yackulic, Charles B.; Blake, Stephen; Bastille-Rousseau, Guillaume
2017-01-01
1. The reasons that lead some animals to seasonally migrate, and others to remain in the same area year-round, are poorly understood. Associations between traits, such as body size, and migration provide clues. For example, larger species and individuals are more likely to migrate.2. One explanation for this size bias in migration is that larger animals are capable of moving faster (movement hypothesis). However, body size is linked to many other biological processes. For instance, the energetic balances of larger animals are generally more sensitive to variation in food density because of body size effects on foraging and metabolism and this sensitivity could drive migratory decisions (forage hypothesis).3. Identifying the primary selective forces that drive migration ultimately requires quantifying fitness impacts over the full annual migratory cycle. Here, we develop a full annual migratory cycle model from metabolic and foraging theory to compare the importance of the forage and movement hypotheses. We parameterize the model for Galapagos tortoises, which were recently discovered to be size-dependent altitudinal migrants.4. The model predicts phenomena not included in model development including maximum body sizes, the body size at which individuals begin to migrate, and the seasonal timing of migration and these predictions generally agree with available data. Scenarios strongly support the forage hypothesis over the movement hypothesis. Furthermore, male Galapagos tortoises on Santa Cruz Island would be unable to grow to their enormous sizes without access to both highlands and lowlands.5. Whereas recent research has focused on links between traits and the migratory phases of the migratory cycle, we find that effects of body size on the non-migratory phases are far more important determinants of the propensity to migrate. Larger animals are more sensitive to changing forage conditions than smaller animals with implications for maintenance of migration and
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The efficiency of interprovincial migration in Canada, 1961-1978.
Islam, M N
1983-05-01
A programming model is used to analyze the impact of the efficiency of migration flows on regional income disparities in Canada. A new method to measure such efficiency is presented in an attempt to show that occupations involving high-level skills and training have efficient migration patterns. The relationship between income differentials and internal migration is discussed.
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Directory of Open Access Journals (Sweden)
Xiping Yang
2016-09-01
Full Text Available Investigating human mobility patterns can help researchers and agencies understand the driving forces of human movement, with potential benefits for urban planning and traffic management. Recent advances in location-aware technologies have provided many new data sources (e.g., mobile phone and social media data for studying human space-time behavioral regularity. Although existing studies have utilized these new datasets to characterize human mobility patterns from various aspects, such as predicting human mobility and monitoring urban dynamics, few studies have focused on human convergence and divergence patterns within a city. This study aims to explore human spatial convergence and divergence and their evolutions over time using large-scale mobile phone location data. Using a dataset from Shenzhen, China, we developed a method to identify spatiotemporal patterns of human convergence and divergence. Eight distinct patterns were extracted, and the spatial distributions of these patterns are discussed in the context of urban functional regions. Thus, this study investigates urban human convergence and divergence patterns and their relationships with the urban functional environment, which is helpful for urban policy development, urban planning and traffic management.
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Zhu, Cansheng; Xiong, Zhaojun; Chen, Xiaohong; Lu, Zhengqi; Zhou, Guoyu; Wang, Dunjing; Bao, Jian; Hu, Xueqiang
2011-08-01
We aimed to investigate the regulation and contribution of vascular endothelial growth factor (VEGF) and sFlt-1(1-3) to human monocytic THP-1 migration. Ad-sFlt-1/FLAG, a recombinant adenovirus carrying the human sFlt-1(1-3) (the first three extracellular domains of FLT-1, the hVEGF receptor-1) gene, was constructed. L929 cells were infected with Ad-sFlt-1/FLAG and the expression of sFlt-1 was detected by immunofluorescent assay and ELISA. Corning(®) Transwell(®) Filter Inserts containing polyethylene terephthalate (PET) membranes with pore sizes of 3 μm were used as an experimental model to simulate THP-1 migration. Five VEGF concentrations (0, 0.1, 1, 10 and 100 ng/ml), four concentrations of sFlt-1(1-3)/FLAG expression supernatants (0.1, 1, 10 and 100 ng/ml), and monocyte chemoattractant protein-1 (MCP-1, 10 ng/ml) were used to test the ability of THP-1 cells to migrate through PET membranes. The sFlt-1(1-3) gene was successfully recombined into Ad-sFlt-1/FLAG. sFlt-1(1-3) was expressed in L929 cells transfected with Ad-sFlt-1/FLAG. THP-1 cell migration increased with increasing concentrations of VEGF, while cell migration decreased with increasing concentrations of sFlt1(1-3)/FLAG. sFlt1(1-3)/FLAG had no effect on MCP-1-induced cell migration. This study demonstrated that VEGF is able to elicit a migratory response in THP-1 cells, and that sFlt-1(1-3) is an effective inhibitor of THP-1 migration towards VEGF.
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Pendleton, Elizabeth; Brothers, Laura; Thieler, E. Robert; Sweeney, Edward
2017-01-01
The U.S. Geological Survey and the National Oceanographic and Atmospheric Administration conducted geophysical and hydrographic surveys, respectively, along the inner-continental shelf of Fenwick and Assateague Islands, Maryland and Virginia over the last 40 years. High resolution bathymetry and backscatter data derived from surveys over the last decade are used to describe the morphology and presence of sand ridges on the inner-continental shelf and measure the change in the position of smaller-scale (10–100 s of meters) seafloor features. Bathymetric surveys from the last 30 years link decadal-scale sand ridge migration patterns to the high-resolution measurements of smaller-scale bedform features. Sand ridge morphology on the inner-shelf changes across-shore and alongshore. Areas of similar sand ridge morphology are separated alongshore by zones where ridges are less pronounced or completely transected by transverse dunes. Seafloor-change analyses derived from backscatter data over a 4–7 year period show that southerly dune migration increases in magnitude from north to south, and the east-west pattern of bedform migration changes ~ 10 km north of the Maryland-Virginia state line. Sand ridge morphology and occurrence and bedform migration changes may be connected to observed changes in geologic framework including topographic highs, deflated zones, and sand availability. Additionally, changes in sand ridge occurrence and morphology may help explain changes in the long-term shoreline trends along Fenwick and Assateague Islands. Although the data presented here cannot quantitatively link sand ridges to sediment transport and shoreline change, it does present a compelling relationship between inner-shelf sand availability and movement, sand ridge occurrence and morphology, geologic framework, and shoreline behavior.
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The challenges of managing migration
Energy Technology Data Exchange (ETDEWEB)
Tacoli, Cecilia
2005-10-15
Migration and urbanisation are driven by economic growth and social change, but also by deepening inequalities. Managing migration should not be equated with curbing it, as this inevitably reduces migrants' rights. But managing population movement whilst respecting the rights of migrants and nonmigrants, supporting the contribution of migration to poverty reduction and economic growth in sending and receiving areas and reducing the human and material costs of movement means that fundamental challenges need to be addressed.
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Directory of Open Access Journals (Sweden)
Andrew M Ramey
Full Text Available Tundra swans (Cygnus columbianus are broadly distributed in North America, use a wide variety of habitats, and exhibit diverse migration strategies. We investigated patterns of hematozoa infection in three populations of tundra swans that breed in Alaska using satellite tracking to infer host movement and molecular techniques to assess the prevalence and genetic diversity of parasites. We evaluated whether migratory patterns and environmental conditions at breeding areas explain the prevalence of blood parasites in migratory birds by contrasting the fit of competing models formulated in an occupancy modeling framework and calculating the detection probability of the top model using Akaike Information Criterion (AIC. We described genetic diversity of blood parasites in each population of swans by calculating the number of unique parasite haplotypes observed. Blood parasite infection was significantly different between populations of Alaska tundra swans, with the highest estimated prevalence occurring among birds occupying breeding areas with lower mean daily wind speeds and higher daily summer temperatures. Models including covariates of wind speed and temperature during summer months at breeding grounds better predicted hematozoa prevalence than those that included annual migration distance or duration. Genetic diversity of blood parasites in populations of tundra swans appeared to be relative to hematozoa prevalence. Our results suggest ecological conditions at breeding grounds may explain differences of hematozoa infection among populations of tundra swans that breed in Alaska.
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Ramey, Andrew M; Ely, Craig R; Schmutz, Joel A; Pearce, John M; Heard, Darryl J
2012-01-01
Tundra swans (Cygnus columbianus) are broadly distributed in North America, use a wide variety of habitats, and exhibit diverse migration strategies. We investigated patterns of hematozoa infection in three populations of tundra swans that breed in Alaska using satellite tracking to infer host movement and molecular techniques to assess the prevalence and genetic diversity of parasites. We evaluated whether migratory patterns and environmental conditions at breeding areas explain the prevalence of blood parasites in migratory birds by contrasting the fit of competing models formulated in an occupancy modeling framework and calculating the detection probability of the top model using Akaike Information Criterion (AIC). We described genetic diversity of blood parasites in each population of swans by calculating the number of unique parasite haplotypes observed. Blood parasite infection was significantly different between populations of Alaska tundra swans, with the highest estimated prevalence occurring among birds occupying breeding areas with lower mean daily wind speeds and higher daily summer temperatures. Models including covariates of wind speed and temperature during summer months at breeding grounds better predicted hematozoa prevalence than those that included annual migration distance or duration. Genetic diversity of blood parasites in populations of tundra swans appeared to be relative to hematozoa prevalence. Our results suggest ecological conditions at breeding grounds may explain differences of hematozoa infection among populations of tundra swans that breed in Alaska.
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Ramey, Andrew M.; Ely, Craig R.; Schmutz, Joel A.; Pearce, John M.; Heard, Darryl J.
2012-01-01
Tundra swans (Cygnus columbianus) are broadly distributed in North America, use a wide variety of habitats, and exhibit diverse migration strategies. We investigated patterns of hematozoa infection in three populations of tundra swans that breed in Alaska using satellite tracking to infer host movement and molecular techniques to assess the prevalence and genetic diversity of parasites. We evaluated whether migratory patterns and environmental conditions at breeding areas explain the prevalence of blood parasites in migratory birds by contrasting the fit of competing models formulated in an occupancy modeling framework and calculating the detection probability of the top model using Akaike Information Criterion (AIC). We described genetic diversity of blood parasites in each population of swans by calculating the number of unique parasite haplotypes observed. Blood parasite infection was significantly different between populations of Alaska tundra swans, with the highest estimated prevalence occurring among birds occupying breeding areas with lower mean daily wind speeds and higher daily summer temperatures. Models including covariates of wind speed and temperature during summer months at breeding grounds better predicted hematozoa prevalence than those that included annual migration distance or duration. Genetic diversity of blood parasites in populations of tundra swans appeared to be relative to hematozoa prevalence. Our results suggest ecological conditions at breeding grounds may explain differences of hematozoa infection among populations of tundra swans that breed in Alaska.
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Circular Migration and Young Child Malnutrition in Guatemala.
Teller, Charles H.; Butz, William P.
This paper examined the relationship between temporary migration and childhood malnutrition in Guatemala and questioned whether migration patterns or low socioeconomic status produced a special risk group. The study emphasized policy implications of high priorities placed on population redistribution in Latin American governments and the…
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Roosts and migrations of swallows
Winkler, David W.
2006-01-01
Swallows of the north temperate zone display a wide variety of territorial behaviour during the breeding season, but as soon as breeding is over, they all appear to adopt a pattern of independent diurnal foraging interleaved with aggregation every night in dense roosts. Swallows generally migrate during the day, feeding on the wing. On many stretches of their annual journeys, their migrations can thus be seen as the simple spatial translation of nocturnal roost sites with foraging routes stra...
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Geovisualization of Local and Regional Migration Using Web-mined Demographics
Schuermann, R. T.; Chow, T. E.
2014-11-01
The intent of this research was to augment and facilitate analyses, which gauges the feasibility of web-mined demographics to study spatio-temporal dynamics of migration. As a case study, we explored the spatio-temporal dynamics of Vietnamese Americans (VA) in Texas through geovisualization of mined demographic microdata from the World Wide Web. Based on string matching across all demographic attributes, including full name, address, date of birth, age and phone number, multiple records of the same entity (i.e. person) over time were resolved and reconciled into a database. Migration trajectories were geovisualized through animated sprites by connecting the different addresses associated with the same person and segmenting the trajectory into small fragments. Intra-metropolitan migration patterns appeared at the local scale within many metropolitan areas. At the scale of metropolitan area, varying degrees of immigration and emigration manifest different types of migration clusters. This paper presents a methodology incorporating GIS methods and cartographic design to produce geovisualization animation, enabling the cognitive identification of migration patterns at multiple scales. Identification of spatio-temporal patterns often stimulates further research to better understand the phenomenon and enhance subsequent modeling.
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The origin and migration of primordial germ cells in sturgeons.
Directory of Open Access Journals (Sweden)
Taiju Saito
Full Text Available Primordial germ cells (PGCs arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super class Actinoptergii, and their developmental pattern is similar to that of amphibians, although their phylogenetic position is an out-group to teleost fishes. Here, we reveal an injection technique for sturgeon eggs allowing visualization of germplasm and PGCs. Using this technique, we demonstrate that the PGCs are generated at the vegetal pole of the egg and they migrate on the yolky cell mass toward the gonadal ridge. We also provide evidence showing that PGCs are specified by inheritance of maternally supplied germplasm. Furthermore, we demonstrate that the migratory mechanism is well-conserved between sturgeon and other remotely related teleosts, such as goldfish, by a single PGCs transplantation (SPT assay. The mode of PGCs specification in sturgeon is similar to that of anurans, but the migration pattern resembles that of teleosts.
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Capturing the age and spatial structures of migration
Rogers, A; Raymer, J; Willekens, F
In this paper we model the structures found in the level (generation) and allocation (distribution) components of age-specific and origin-destination-specific migration flows. For the examples, we examine the regional migration patterns in the USA for four periods: 1955-60, 1965-70, 1975-80, and
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Migration in Asia-Europe Relations
DEFF Research Database (Denmark)
Juego, Bonn
2010-01-01
There is a remarkable difference between viewing migration as a 'social integration' issue, on the one hand, and migration as a 'social relation'. The idea of ‘social integration’ has unrealistic assumptions that see migration as a one-way process, that societies and human relations are static......, and that migrants are mechanical. Policies that are founded on unrealistic assumptions are most likely to generate tensions, conflicts, and contradictions. For a migration process to succeed in forging social harmony and development, it is therefore of decisive and crucial importance to regard migration...... as a ‘social relation’. This is simply because successful migration has to be a harmonious synergy between the migrants (and also the sending countries where they come from) and the receiving society (and its people). As indicated, migrants enter into the receiving society not merely as a passive commodity...
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Liang, Zai; Chunyu, Miao David
2013-07-01
This paper tests a new strategy for simultaneously studying internal migration within, and international migration from, China. Our theoretical discussion draws on ideas from migration-networks theory and studies of the transition to a market-oriented economy. Data collection is modelled on the Mexican Migration Project. We find that education is more important in initiating internal migration than international migration. Second, although the role of migration networks at a community level seems similar to that for Mexico-USA migration, the networks at a family level show a different pattern. Third, there is evidence that internal and international migration are competing options. Finally, we find that individuals with cadres (public officials) in the family are less likely to undertake internal migration, but more likely to participate in international migration, a finding that highlights the continuing significance of the cadres in coastal rural China.
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Curtis, Katherine J; Fussell, Elizabeth; DeWaard, Jack
2015-08-01
Changes in the human migration systems of the Gulf of Mexico coastline counties affected by Hurricanes Katrina and Rita provide an example of how climate change may affect coastal populations. Crude climate change models predict a mass migration of "climate refugees," but an emerging literature on environmental migration suggests that most migration will be short-distance and short-duration within existing migration systems, with implications for the population recovery of disaster-stricken places. In this research, we derive a series of hypotheses on recovery migration predicting how the migration system of hurricane-affected coastline counties in the Gulf of Mexico was likely to have changed between the pre-disaster and the recovery periods. We test these hypotheses using data from the Internal Revenue Service on annual county-level migration flows, comparing the recovery period migration system (2007-2009) with the pre-disaster period (1999-2004). By observing county-to-county ties and flows, we find that recovery migration was strong: the migration system of the disaster-affected coastline counties became more spatially concentrated, while flows within it intensified and became more urbanized. Our analysis demonstrates how migration systems are likely to be affected by the more intense and frequent storms anticipated by climate change scenarios, with implications for the population recovery of disaster-affected places.
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Cross-Border Movements, Female Migration and Human Rights : a ...
International Development Research Centre (IDRC) Digital Library (Canada)
This project will examine the relationship between migration, prostitution and trafficking with respect to cross-border movement of women between three South Asian countries: Bangladesh, India and Nepal. Researchers will. conduct an extensive review of the literature on female migration in the three countries;; examine ...
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International Nuclear Information System (INIS)
Nos, V.; Rosa, J. C. de la; Hernandez, H.
2011-01-01
This paper describes the systematics of adaptation and conversion of models, to migrate the detailed analysis of human actions from the APS (in operation at power) of NPP Vandellos, which uses the HCR to SAIC-CRT model. Are offered the results achieved after the migration and the main conclusions.
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Tan, Powell Patrick Cheng; French, Leon; Pavlidis, Paul
2013-01-01
An important goal in neuroscience is to understand gene expression patterns in the brain. The recent availability of comprehensive and detailed expression atlases for mouse and human creates opportunities to discover global patterns and perform cross-species comparisons. Recently we reported that the major source of variation in gene transcript expression in the adult normal mouse brain can be parsimoniously explained as reflecting regional variation in glia to neuron ratios, and is correlated with degree of connectivity and location in the brain along the anterior-posterior axis. Here we extend this investigation to two gene expression assays of adult normal human brains that consisted of over 300 brain region samples, and perform comparative analyses of brain-wide expression patterns to the mouse. We performed principal components analysis (PCA) on the regional gene expression of the adult human brain to identify the expression pattern that has the largest variance. As in the mouse, we observed that the first principal component is composed of two anti-correlated patterns enriched in oligodendrocyte and neuron markers respectively. However, we also observed interesting discordant patterns between the two species. For example, a few mouse neuron markers show expression patterns that are more correlated with the human oligodendrocyte-enriched pattern and vice-versa. In conclusion, our work provides insights into human brain function and evolution by probing global relationships between regional cell type marker expression patterns in the human and mouse brain.
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Genetic structuring and migration patterns of Atlantic bigeye tuna, Thunnus obesus (Lowe, 1839
Directory of Open Access Journals (Sweden)
Beerli Peter
2008-09-01
Full Text Available Abstract Background Large pelagic fishes are generally thought to have little population genetic structuring based on their cosmopolitan distribution, large population sizes and high dispersal capacities. However, gene flow can be influenced by ecological (e.g. homing behaviour and physical (e.g. present-day ocean currents, past changes in sea temperature and levels factors. In this regard, Atlantic bigeye tuna shows an interesting genetic structuring pattern with two highly divergent mitochondrial clades (Clades I and II, which are assumed to have been originated during the last Pleistocene glacial maxima. We assess genetic structure patterns of Atlantic bigeye tuna at the nuclear level, and compare them with mitochondrial evidence. Results We examined allele size variation of nine microsatellite loci in 380 individuals from the Gulf of Guinea, Canary, Azores, Canada, Indian Ocean, and Pacific Ocean. To investigate temporal stability of genetic structure, three Atlantic Ocean sites were re-sampled a second year. Hierarchical AMOVA tests, RST pairwise comparisons, isolation by distance (Mantel tests, Bayesian clustering analyses, and coalescence-based migration rate inferences supported unrestricted gene flow within the Atlantic Ocean at the nuclear level, and therefore interbreeding between individuals belonging to both mitochondrial clades. Moreover, departures from HWE in several loci were inferred for the samples of Guinea, and attributed to a Wahlund effect supporting the role of this region as a spawning and nursery area. Our microsatellite data supported a single worldwide panmictic unit for bigeye tunas. Despite the strong Agulhas Current, immigration rates seem to be higher from the Atlantic Ocean into the Indo-Pacific Ocean, but the actual number of individuals moving per generation is relatively low compared to the large population sizes inhabiting each ocean basin. Conclusion Lack of congruence between mt and nuclear evidences, which
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Genetic structuring and migration patterns of Atlantic bigeye tuna, Thunnus obesus (Lowe, 1839).
Gonzalez, Elena G; Beerli, Peter; Zardoya, Rafael
2008-09-17
Large pelagic fishes are generally thought to have little population genetic structuring based on their cosmopolitan distribution, large population sizes and high dispersal capacities. However, gene flow can be influenced by ecological (e.g. homing behaviour) and physical (e.g. present-day ocean currents, past changes in sea temperature and levels) factors. In this regard, Atlantic bigeye tuna shows an interesting genetic structuring pattern with two highly divergent mitochondrial clades (Clades I and II), which are assumed to have been originated during the last Pleistocene glacial maxima. We assess genetic structure patterns of Atlantic bigeye tuna at the nuclear level, and compare them with mitochondrial evidence. We examined allele size variation of nine microsatellite loci in 380 individuals from the Gulf of Guinea, Canary, Azores, Canada, Indian Ocean, and Pacific Ocean. To investigate temporal stability of genetic structure, three Atlantic Ocean sites were re-sampled a second year. Hierarchical AMOVA tests, RST pairwise comparisons, isolation by distance (Mantel) tests, Bayesian clustering analyses, and coalescence-based migration rate inferences supported unrestricted gene flow within the Atlantic Ocean at the nuclear level, and therefore interbreeding between individuals belonging to both mitochondrial clades. Moreover, departures from HWE in several loci were inferred for the samples of Guinea, and attributed to a Wahlund effect supporting the role of this region as a spawning and nursery area. Our microsatellite data supported a single worldwide panmictic unit for bigeye tunas. Despite the strong Agulhas Current, immigration rates seem to be higher from the Atlantic Ocean into the Indo-Pacific Ocean, but the actual number of individuals moving per generation is relatively low compared to the large population sizes inhabiting each ocean basin. Lack of congruence between mt and nuclear evidences, which is also found in other species, most likely reflects
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Chen, Luoping; Zheng, Lisha; Jiang, Jingyi; Gui, Jinpeng; Zhang, Lingyu; Huang, Yan; Chen, Xiaofang; Ji, Jing; Fan, Yubo
2016-09-01
Calcium hydroxide has been extensively used as the gold standard for direct pulp capping in clinical dentistry. It induces proliferation, migration, and mineralization in dental pulp stem cells (DPSCs), but the underlying mechanisms are still unclear. The aim of this study was to investigate the role of the mitogen-activated protein (MAP) kinase pathway in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Human DPSCs between passages 3 and 6 were used. DPSCs were preincubated with inhibitors of MAP kinases and cultured with calcium hydroxide. The phosphorylated MAP kinases were detected by Western blot analysis. Cell viability was analyzed via the methylthiazol tetrazolium assay. Cell migration was estimated using the wound healing assay. Alkaline phosphatase (ALP) expression was analyzed using the ALP staining assay. Mineralization was studied by alizarin red staining analysis. Calcium hydroxide significantly promoted the phosphorylation of the c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase. The inhibition of JNK and p38 signaling abolished calcium hydroxide-induced proliferation of DPSCs. The inhibition of JNK, p38, and extracellular signal-regulated kinase signaling suppressed the migration, ALP expression, and mineralization of DPSCs. Our study showed that the MAP kinase pathway was involved in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
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Freymann, Undine; Metzlaff, Sebastian; Krüger, Jan-Philipp; Hirsh, Glen; Endres, Michaela; Petersen, Wolf; Kaps, Christian
2016-06-01
To evaluate the effect of 10% human serum (HS), 5% platelet-rich plasma (PRP), and 5% autologous conditioned plasma (ACP) on migration, proliferation, and extracellular matrix (ECM) synthesis of human meniscus cells. Cell migration and proliferation on stimulation with HS, PRP, and ACP were assessed by chemotaxis assays and measurement of genomic DNA content. Meniscus cells were cultivated in pellets stimulated with 10% HS, 5% PRP, or 5% ACP. Meniscal ECM formation was evaluated by histochemical staining of collagen type I, type II, and proteoglycans and by analysis of fibrochondrocyte marker gene expression. Human meniscus cells were significantly attracted by all 3 blood-derived products (10% HS and 5% ACP: P = .0001, 5% PRP: P = .0002). Cell proliferation at day 9 was significantly increased on stimulation with 10% HS (P = .0001) and 5% PRP (P = .0002) compared with 5% ACP and controls. Meniscus cell pellet cultures showed the formation of a well-structured meniscal ECM with deposition of collagen type I, type II, and proteoglycans on stimulation with 10% HS, whereas 5% PRP or 5% ACP resulted in the formation of an inhomogeneous and more fibrous ECM. Stimulation with 10% HS and 5% ACP showed a significant induction of fibrochondrocyte marker genes such as aggrecan (HS: P = .0002, ACP: P = .0147), cartilage oligomeric matrix protein (HS: P = .0002, ACP: P = .0005), and biglycan (HS: P = .0002, ACP: P = .0003), whereas PRP showed no inducing effect. Among all tested blood-derived products, only stimulation with HS showed the formation of a meniscal ECM as well as positive cell proliferating and migrating effects in vitro. Regarding a potential biological repair of nonvascular meniscus lesions, our results may point toward the use of HS as a beneficial augment in regenerative meniscus repair approaches. Our findings may suggest that HS might be a beneficial augment for meniscus repair. Copyright © 2016 Arthroscopy Association of North America. Published
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Patterned control of human locomotion
Lacquaniti, Francesco; Ivanenko, Yuri P; Zago, Myrka
2012-01-01
There is much experimental evidence for the existence of biomechanical constraints which simplify the problem of control of multi-segment movements. In addition, it has been hypothesized that movements are controlled using a small set of basic temporal components or activation patterns, shared by several different muscles and reflecting global kinematic and kinetic goals. Here we review recent studies on human locomotion showing that muscle activity is accounted for by a combination of few basic patterns, each one timed at a different phase of the gait cycle. Similar patterns are involved in walking and running at different speeds, walking forwards or backwards, and walking under different loading conditions. The corresponding weights of distribution to different muscles may change as a function of the condition, allowing highly flexible control. Biomechanical correlates of each activation pattern have been described, leading to the hypothesis that the co-ordination of limb and body segments arises from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle activations need only intervene during limited time epochs to force intrinsic oscillations of the system when energy is lost. PMID:22411012
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Patterned control of human locomotion.
Lacquaniti, Francesco; Ivanenko, Yuri P; Zago, Myrka
2012-05-15
There is much experimental evidence for the existence of biomechanical constraints which simplify the problem of control of multi-segment movements. In addition, it has been hypothesized that movements are controlled using a small set of basic temporal components or activation patterns, shared by several different muscles and reflecting global kinematic and kinetic goals. Here we review recent studies on human locomotion showing that muscle activity is accounted for by a combination of few basic patterns, each one timed at a different phase of the gait cycle. Similar patterns are involved in walking and running at different speeds, walking forwards or backwards, and walking under different loading conditions. The corresponding weights of distribution to different muscles may change as a function of the condition, allowing highly flexible control. Biomechanical correlates of each activation pattern have been described, leading to the hypothesis that the co-ordination of limb and body segments arises from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle activations need only intervene during limited time epochs to force intrinsic oscillations of the system when energy is lost.
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Patterns of migrating soaring migrants indicate attraction to marine wind farms.
Skov, Henrik; Desholm, Mark; Heinänen, Stefan; Kahlert, Johnny A; Laubek, Bjarke; Jensen, Niels Einar; Žydelis, Ramūnas; Jensen, Bo Præstegaard
2016-12-01
Monitoring of bird migration at marine wind farms has a short history, and unsurprisingly most studies have focused on the potential for collisions. Risk for population impacts may exist to soaring migrants such as raptors with K-strategic life-history characteristics. Soaring migrants display strong dependence on thermals and updrafts and an affinity to land areas and islands during their migration, a behaviour that creates corridors where raptors move across narrow straits and sounds and are attracted to islands. Several migration corridors for soaring birds overlap with the development regions for marine wind farms in NW Europe. However, no empirical data have yet been available on avoidance or attraction rates and behavioural reactions of soaring migrants to marine wind farms. Based on a post-construction monitoring study, we show that all raptor species displayed a significant attraction behaviour towards a wind farm. The modified migratory behaviour was also significantly different from the behaviour at nearby reference sites. The attraction was inversely related to distance to the wind farm and was primarily recorded during periods of adverse wind conditions. The attraction behaviour suggests that migrating raptor species are far more at risk of colliding with wind turbines at sea than hitherto assessed. © 2016 The Author(s).
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Evidence of Levy walk foraging patterns in human hunter-gatherers.
Raichlen, David A; Wood, Brian M; Gordon, Adam D; Mabulla, Audax Z P; Marlowe, Frank W; Pontzer, Herman
2014-01-14
When searching for food, many organisms adopt a superdiffusive, scale-free movement pattern called a Lévy walk, which is considered optimal when foraging for heterogeneously located resources with little prior knowledge of distribution patterns [Viswanathan GM, da Luz MGE, Raposo EP, Stanley HE (2011) The Physics of Foraging: An Introduction to Random Searches and Biological Encounters]. Although memory of food locations and higher cognition may limit the benefits of random walk strategies, no studies to date have fully explored search patterns in human foraging. Here, we show that human hunter-gatherers, the Hadza of northern Tanzania, perform Lévy walks in nearly one-half of all foraging bouts. Lévy walks occur when searching for a wide variety of foods from animal prey to underground tubers, suggesting that, even in the most cognitively complex forager on Earth, such patterns are essential to understanding elementary foraging mechanisms. This movement pattern may be fundamental to how humans experience and interact with the world across a wide range of ecological contexts, and it may be adaptive to food distribution patterns on the landscape, which previous studies suggested for organisms with more limited cognition. Additionally, Lévy walks may have become common early in our genus when hunting and gathering arose as a major foraging strategy, playing an important role in the evolution of human mobility.
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The determinants of internal migration in Turkey
Gökhan, Ali; Gokhan, Ali; Filiztekin, Alpay
2008-01-01
Internal migration has had a great impact on Turkey’s population dynamics for decades. According to the 2000 population census, nearly 28% percent of the population was born in a different province that they now reside in. This ratio goes up to 62% for Istanbul, a major province that has drawn migrants for years. Although, it is claimed in numerous studies that rural-urban migration that centers on a few urban areas seems to be the predominant pattern of internal migration, we aim to investig...
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Rural migration in southern Nevada
International Nuclear Information System (INIS)
Mosser, D.; Soden, D.L.
1993-01-01
This study reviews the history of migration in two rural counties in Southern Nevada. It is part of a larger study about the impact of a proposed high-level nuclear waste repository on, in and out-migration patterns in the state. The historical record suggests a boom and bust economic cycle has predominated in the region for the past century creating conditions that should be taken into account, by decision makers, when ascertaining the long-term impacts of the proposed repository
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CD44 regulates cell migration in human colon cancer cells via Lyn kinase and AKT phosphorylation.
Subramaniam, Venkateswaran; Vincent, Isabella R; Gardner, Helena; Chan, Emily; Dhamko, Helena; Jothy, Serge
2007-10-01
Colon cancer is among the leading causes of cancer death in North America. CD44, an adhesion and antiapoptotic molecule is overexpressed in colon cancer. Cofilin is involved in the directional motility of cells. In the present study, we looked at how CD44 might modulate cell migration in human colon cancer via cofilin. We used a human colon cancer cell line, HT29, which expresses CD44, HT29 where CD44 expression was knocked down by siRNA, SW620, a human colon cancer cell line which does not express CD44, stably transfected exons of CD44 in SW620 cells and the colon from CD44 knockout and wild-type mouse. Western blot analysis of siRNA CD44 lysates showed increased level of AKT phosphorylation and decreased level of cofilin expression. Similar results were also observed with SW620 cells and CD44 knockout mouse colon lysates. Experiments using the AKT phosphorylation inhibitor LY294002 indicate that AKT phosphorylation downregulates cofilin. Immunoprecipitation studies showed CD44 complex formation with Lyn, providing an essential link between CD44 and AKT phosphorylation. LY294002 also stabilized Lyn from phosphorylated AKT, suggesting an interaction between Lyn and AKT phosphorylation. Immunocytochemistry showed that cofilin and Lyn expression were downregulated in siRNA CD44 cells and CD44 knockout mouse colon. siRNA CD44 cells had significantly less migration compared to HT29 vector. Given the well-defined roles of CD44, phosphorylated AKT in apoptosis and cancer, these results indicate that CD44-induced cell migration is dependent on its complex formation with Lyn and its consequent regulation of AKT phosphorylation and cofilin expression.
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Markov Chains for Investigating and Predicting Migration: A Case from Southwestern China
Qin, Bo; Wang, Yiyu; Xu, Haoming
2018-03-01
In order to accurately predict the population’s happiness, this paper conducted two demographic surveys on a new district of a city in western China, and carried out a dynamic analysis using related mathematical methods. This paper argues that the migration of migrants in the city will change the pattern of spatial distribution of human resources in the city and thus affect the social and economic development in all districts. The migration status of the population will change randomly with the passage of time, so it can be predicted and analyzed through the Markov process. The Markov process provides the local government and decision-making bureau a valid basis for the dynamic analysis of the mobility of migrants in the city as well as the ways for promoting happiness of local people’s lives.
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Rural-urban migration in a developing country: Botswana, Africa.
Tarver, J D; Miller, H M
1987-01-01
Trends in internal migration in Botswana are analyzed, with a focus on rural-urban migration. Data are from the 1981 census and from a survey carried out in 1979. The authors note that even though the predominance of subsistence agriculture acts as a deterrent to rural-urban migration, it is probable that the total and percentage of people living in urban areas will increase. However, the magnitude and pattern of future migration will fluctuate over time as social and economic conditions change.
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Lin, Hong Reng; Heish, Chao-Wen; Liu, Cheng-Hui; Muduli, Saradaprasan; Li, Hsing-Fen; Higuchi, Akon; Kumar, S. Suresh; Alarfaj, Abdullah A.; Munusamy, Murugan A.; Hsu, Shih-Tien; Chen, Da-Chung; Benelli, Giovanni; Murugan, Kadarkarai; Cheng, Nai-Chen; Wang, Han-Chow; Wu, Gwo-Jang
2017-01-01
Human adipose-derived stem cells (hADSCs) are easily isolated from fat tissue without ethical concerns, but differ in purity, pluripotency, differentiation ability, and stem cell marker expression, depending on the isolation method. We isolated hADSCs from a primary fat tissue solution using: (1) conventional culture, (2) a membrane filtration method, (3) a membrane migration method where the primary cell solution was permeated through membranes, adhered hADSCs were cultured, and hADSCs migrated out from the membranes. Expression of mesenchymal stem cell markers and pluripotency genes, and osteogenic differentiation were compared for hADSCs isolated by different methods using nylon mesh filter membranes with pore sizes ranging from 11 to 80 μm. hADSCs isolated by the membrane migration method had the highest MSC surface marker expression and efficient differentiation into osteoblasts. Osteogenic differentiation ability of hADSCs and MSC surface marker expression were correlated, but osteogenic differentiation ability and pluripotent gene expression were not. PMID:28071738
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SiMA: A simplified migration assay for analyzing neutrophil migration.
Weckmann, Markus; Becker, Tim; Nissen, Gyde; Pech, Martin; Kopp, Matthias V
2017-07-01
In lung inflammation, neutrophils are the first leukocytes migrating to an inflammatory site, eliminating pathogens by multiple mechanisms. The term "migration" describes several stages of neutrophil movement to reach the site of inflammation, of which the passage of the interstitium and basal membrane of the airway are necessary to reach the site of bronchial inflammation. Currently, several methods exist (e.g., Boyden Chamber, under-agarose assay, or microfluidic systems) to assess neutrophil mobility. However, these methods do not allow for parameterization on single cell level, that is, the individual neutrophil pathway analysis is still considered challenging. This study sought to develop a simplified yet flexible method to monitor and quantify neutrophil chemotaxis by utilizing commercially available tissue culture hardware, simple video microscopic equipment and highly standardized tracking. A chemotaxis 3D µ-slide (IBIDI) was used with different chemoattractants [interleukin-8 (IL-8), fMLP, and Leukotriene B4 (LTB 4 )] to attract neutrophils in different matrices like Fibronectin (FN) or human placental matrix. Migration was recorded for 60 min using phase contrast microscopy with an EVOS ® FL Cell Imaging System. The images were normalized and texture based image segmentation was used to generate neutrophil trajectories. Based on these spatio-temporal information a comprehensive parameter set is extracted from each time series describing the neutrophils motility, including velocity and directness and neutrophil chemotaxis. To characterize the latter one, a sector analysis was employed enabling the quantification of the neutrophils response to the chemoattractant. Using this hard- and software framework we were able to identify typical migration profiles of the chemoattractants IL-8, fMLP, and LTB 4 , the effect of the matrices FN versus HEM as well as the response to different medications (Prednisolone). Additionally, a comparison of four asthmatic and
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Engineering of silicon surfaces at the micro- and nanoscales for cell adhesion and migration control
Directory of Open Access Journals (Sweden)
Torres-Costa V
2012-02-01
Full Text Available Vicente Torres-Costa1, Gonzalo Martínez-Muñoz2, Vanessa Sánchez-Vaquero3, Álvaro Muñoz-Noval1, Laura González-Méndez3, Esther Punzón-Quijorna1,4, Darío Gallach-Pérez1, Miguel Manso-Silván1, Aurelio Climent-Font1,4, Josefa P García-Ruiz3, Raúl J Martín-Palma11Department of Applied Physics, 2Department of Computer Science, 3Department of Molecular Biology, 4Centre for Micro Analysis of Materials, Universidad Autónoma de Madrid, Madrid, SpainAbstract: The engineering of surface patterns is a powerful tool for analyzing cellular communication factors involved in the processes of adhesion, migration, and expansion, which can have a notable impact on therapeutic applications including tissue engineering. In this regard, the main objective of this research was to fabricate patterned and textured surfaces at micron- and nanoscale levels, respectively, with very different chemical and topographic characteristics to control cell–substrate interactions. For this task, one-dimensional (1-D and two-dimensional (2-D patterns combining silicon and nanostructured porous silicon were engineered by ion beam irradiation and subsequent electrochemical etch. The experimental results show that under the influence of chemical and morphological stimuli, human mesenchymal stem cells polarize and move directionally toward or away from the particular stimulus. Furthermore, a computational model was developed aiming at understanding cell behavior by reproducing the surface distribution and migration of human mesenchymal stem cells observed experimentally.Keywords: surface patterns, silicon, hMSCs, ion-beam patterning
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Migration characteristics and early clinical results of the NANOS® short-stem hip arthroplasty.
Kaipel, Martin; Grabowiecki, Phillip; Sinz, Katrina; Farr, Sebastian; Sinz, Günter
2015-05-01
Femoral short stems promise essential advantages in total hip arthroplasty. Up to now, only short- and midterm clinical studies exist. Data on early stem migration that could predict later aseptic loosening at an early stage are rare. The purpose of this study was to assess migration patterns and clinical outcome 2 years after hip replacement by a metaphyseal anchored cementless short stem. Migration data and clinical results were prospectively assessed in 49 patients. Clinical outcome was measured using the Harris Hip Score (HHS). Migration analyses were performed using the computer-assisted Einzel-Bild-Roentgen-Analyse (EBRA) system. At 2 years after surgery, none of the implants needed revision, and HHS increased from 47.9 up to 98.1. Of 49 patients, 5 (10%) showed increased vertical stem migration (1.5 mm/2a) that might predict late aseptic loosening. Of 49 stems, 44 (90%) showed stable migration patterns indicating a beneficial long-term outcome. Results of this study confirm the excellent clinical data of previous works. Migration patterns strongly suggest that short-stem arthroplasty is not only an innovative but also a reliable strategy in total hip replacement.
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The Globalisation of migration
Directory of Open Access Journals (Sweden)
Milan Mesić
2002-04-01
deterritorialisation of identity, as well as a hybridisation of cultural patterns, bring into question old notions of separate cultures in delimited areas. To sum up, the discussion of the mentioned themes supports the fundamental thesis of the paper, i.e. that international migration is a constitutive part of the process of globalisation.
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Flippen, Chenoa
2013-01-01
While the link between geographic and social mobility has long been a cornerstone of sociological approaches to migration, recent research has cast doubt on the economic returns to internal U.S. migration. Moreover, important racial disparities in migration patterns remain poorly understood. Drawing on data from the 2000 census, I reappraise the link between migration and social mobility by taking relative deprivation into consideration. I examine the association between migration, disaggregated by region of origin and destination, and absolute and relative earnings and occupational prestige, separately by race. Findings lend new insight into the theoretical and stratification implications of growing racial disparities in migration patterns; while both blacks and whites who move north-south generally average lower absolute incomes than their stationary northern peers, they enjoy significantly higher relative social position. Moreover, the relative “gains” to migration are substantially larger for blacks than whites. The opposite patterns obtain for south-north migration. PMID:24391221
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Hypoxia stimulates invasion and migration of human cervical cancer ...
Indian Academy of Sciences (India)
Here we show that hypoxiaincreases tumour cell invasion and migration by the modulation of Rab11, an important molecule for vesicular trafficking.In our study, we found that Rab11, together with the activation of Rac1, could stimulate invasion and migration of cervicalcancer cell lines HeLa/SiHa in hypoxia. Activation of ...
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Fussell, Elizabeth; DeWaard, Jack
2015-01-01
Changes in the human migration systems of Hurricane Katrina- and Rita-affected Gulf of Mexico coastline counties provide an example of how climate change may affect coastal populations. Crude climate change models predict a mass migration of “climate refugees,” but an emerging literature on environmental migration suggests most migration will be short-distance and short-duration within existing migration systems, with implications for the population recovery of disaster-struck places. In this research, we derive a series of hypotheses on recovery migration predicting how the migration system of hurricane-affected coastline counties in the Gulf of Mexico was likely to have changed between the pre-disaster and the recovery periods. We test these hypotheses using data from the Internal Revenue Service on annual county-level migration flows, comparing the recovery period migration system (2007–2009) to the pre-disaster period (1999–2004). By observing county-to-county ties and flows we find that recovery migration was strong, as the migration system of the disaster-affected coastline counties became more spatially concentrated while flows within it intensified and became more urbanized. Our analysis demonstrates how migration systems are likely to be affected by the more intense and frequent storms anticipated by climate change scenarios with implications for the population recovery of disaster-affected places. PMID:26084982
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Migration and work-life balance in the periphery
Nørgaard, Helle
2013-01-01
This paper will address the potential of teleworking in relation to migration decisions to leave or stay in rural, peripheral locations. Various studies document long term patterns of migration from rural to urban areas but also urban-rural migration as well as significant differences between rural localities in regard to population growth or decline.Mobility is generally low in Denmark, decreases with age and is very low from age 50 whereas mobility is high when establishing family. Thus, mi...
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Wang, Wei; Liu, Haijun; Dai, Xiaoniu; Fang, Shencun; Wang, Xingang; Zhang, Yingming; Yao, Honghong; Zhang, Xilong; Chao, Jie
2015-11-18
Phagocytosis of SiO2 into the lung causes an inflammatory cascade that results in fibroblast proliferation and migration, followed by fibrosis. Clinical evidence has indicated that the activation of alveolar macrophages by SiO2 produces rapid and sustained inflammation characterized by the generation of monocyte chemotactic protein 1, which, in turn, induces fibrosis. However, the details of events downstream of monocyte chemotactic protein 1 activity in pulmonary fibroblasts remain unclear. Here, to elucidate the role of p53 in fibrosis induced by silica, both the upstream molecular mechanisms and the functional effects on cell proliferation and migration were investigated. Experiments using primary cultured adult human pulmonary fibroblasts led to the following results: 1) SiO2 treatment resulted in a rapid and sustained increase in p53 and PUMA protein levels; 2) the MAPK and PI3K pathways were involved in the SiO2-induced alteration of p53 and PUMA expression; and 3) RNA interference targeting p53 and PUMA prevented the SiO2-induced increases in fibroblast activation and migration. Our study elucidated a link between SiO2-induced p53/PUMA expression in fibroblasts and cell migration, thereby providing novel insight into the potential use of p53/PUMA in the development of novel therapeutic strategies for silicosis treatment.
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EDGE2D Simulations of JET 13C Migration Experiments
International Nuclear Information System (INIS)
Strachan, J.D.; Coad, J.P.; Corrigan, G.; Matthews, G.F.; Spence, J.
2004-01-01
Material migration has received renewed interest due to tritium retention associated with carbon transport to remote vessel locations. Those results influence the desirability of carbon usage on ITER. Subsequently, additional experiments have been performed, including tracer experiments attempting to identify material migration from specific locations. In this paper, EDGE2D models a well-diagnosed JET 13 C tracer migration experiment. The role of SOL flows upon the migration patterns is identified
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Nawrotzki, Raphael J.; Riosmena, Fernando; Hunter, Lori M.
2013-01-01
Environmental and climatic changes have shaped human mobility for thousands of years and research on the migration-environment connection has proliferated in the past several years. Even so, little work has focused on Latin America or on international movement. Given rural Mexico’s dependency on primary sector activities involving various natural resources, and the existence of well-established transnational migrant networks, we investigate the association between rainfall patterns and U.S.-bound migration from rural locales, a topic of increasing policy relevance. The New Economics of Labor Migration (NELM) theory provides background, positing that migration represents a household-level risk management strategy. We use data from the year 2000 Mexican census for rural localities and socioeconomic and state-level precipitation data provided by the Mexican National Institute for Statistics and Geography. Multilevel models assess the impact of rainfall change on household-level international out-migration while controlling for relevant sociodemographic and economic factors. A decrease in precipitation is significantly associated with U.S.-bound migration, but only for dry Mexican states. This finding suggests that programs and policies aimed at reducing Mexico-U.S. migration should seek to diminish the climate/weather vulnerability of rural Mexican households, for example by supporting sustainable irrigation systems and subsidizing drought-resistant crops. PMID:23913999
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Migration of heavy natural radionuclides in a humid climatic zone
International Nuclear Information System (INIS)
Titaeva, N.A.; Alexakhin, R.M.; Taskaev, A.I.; Maslov, V.I.
1980-01-01
Regularities and biochemical peculiarities of the migrations of heavy natural radionuclides in the environment are examined, with special reference to two regions in a humid climatic zone representing natural patterns of radionuclide distribution and to four plots artificially contaminated with high levels of natural radioactivity more than 20 years previously. It was determined that the migration of thorium, uranium, and radium isotopes through the rock-water-soil-plant system is dependent on many physiochemical properties of these radionuclides, their compounds, and the local environment. Isotopic activity ratios provide a useful tool for studying the direction of radionuclide migration and its influence on observed distribution patterns
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Climate change-related migration and infectious disease.
McMichael, Celia
2015-01-01
Anthropogenic climate change will have significant impacts on both human migration and population health, including infectious disease. It will amplify and alter migration pathways, and will contribute to the changing ecology and transmission dynamics of infectious disease. However there has been limited consideration of the intersections between migration and health in the context of a changing climate. This article argues that climate-change related migration - in conjunction with other drivers of migration - will contribute to changing profiles of infectious disease. It considers infectious disease risks for different climate-related migration pathways, including: forced displacement, slow-onset migration particularly to urban-poor areas, planned resettlement, and labor migration associated with climate change adaptation initiatives. Migration can reduce vulnerability to climate change, but it is critical to better understand and respond to health impacts - including infectious diseases - for migrant populations and host communities.
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International migration and related policies in europe 1950-2015
Penninx, R.
2016-01-01
Immigration in Europe has been shaped by: a) its particular development in time; b) the geographical patterns of migration within and towards European countries; and c) the shifting types of migration and characteristics of migrants involved. The first part of this contribution outlines changes in
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Circadian flight schedules in night-migrating birds caught on migration.
Coppack, Timothy; Becker, Simon F; Becker, Philipp J J
2008-12-23
Many species of migratory birds migrate in a series of solitary nocturnal flights. Between flights, they stop to rest and refuel for the next segment of their journey. The mechanism controlling this behaviour has long remained elusive. Here, we show that wild-caught migratory redstarts (Phoenicurus phoenicurus) are consistent in their flight scheduling. An advanced videographic system enabled us to determine the precise timing of flight activity in redstarts caught at a northern European stopover site during their return trip from Africa. Birds were held captive for three days in the absence of photoperiodic cues (constant dim light) and under permanent food availability. Despite the absence of external temporal cues, birds showed clear bimodal activity patterns: intense nocturnal activity alternating with diurnal foraging and resting periods. The onset of their migratory activity coincided with the time of local sunset and was individually consistent on consecutive nights. The data demonstrate that night-migrating birds are driven by autonomous circadian clocks entrained by sunset cues. This timekeeping system is probably the key factor in the overall control of nocturnal songbird migration.
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Middleton, Arthur D.; Kauffman, Matthew J.; McWhirter, Douglas E.; Cook, John G.; Cook, Rachel C.; Nelson, Abigail A.; Jimenez, Michael D.; Klaver, Robert W.
2013-01-01
Migration is a striking behavioral strategy by which many animals enhance resource acquisition while reducing predation risk. Historically, the demographic benefits of such movements made migration common, but in many taxa the phenomenon is considered globally threatened. Here we describe a long-term decline in the productivity of elk (Cervus elaphus) that migrate through intact wilderness areas to protected summer ranges inside Yellowstone National Park, USA. We attribute this decline to a long-term reduction in the demographic benefits that ungulates typically gain from migration. Among migratory elk, we observed a 21-year, 70% reduction in recruitment and a 4-year, 19% depression in their pregnancy rate largely caused by infrequent reproduction of females that were young or lactating. In contrast, among resident elk, we have recently observed increasing recruitment and a high rate of pregnancy. Landscape-level changes in habitat quality and predation appear to be responsible for the declining productivity of Yellowstone migrants. From 1989 to 2009, migratory elk experienced an increasing rate and shorter duration of green-up coincident with warmer spring–summer temperatures and reduced spring precipitation, also consistent with observations of an unusually severe drought in the region. Migrants are also now exposed to four times as many grizzly bears (Ursus arctos) and wolves (Canis lupus) as resident elk. Both of these restored predators consume migratory elk calves at high rates in the Yellowstone wilderness but are maintained at low densities via lethal management and human disturbance in the year-round habitats of resident elk. Our findings suggest that large-carnivore recovery and drought, operating simultaneously along an elevation gradient, have disproportionately influenced the demography of migratory elk. Many migratory animals travel large geographic distances between their seasonal ranges. Changes in land use and climate that disparately influence
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Middleton, Arthur D; Kauffman, Matthew J; McWhirter, Douglas E; Cook, John G; Cook, Rachel C; Nelson, Abigail A; Jimenez, Michael D; Klaver, Robert W
2013-06-01
Migration is a striking behavioral strategy by which many animals enhance resource acquisition while reducing predation risk. Historically, the demographic benefits of such movements made migration common, but in many taxa the phenomenon is considered globally threatened. Here we describe a long-term decline in the productivity of elk (Cervus elaphus) that migrate through intact wilderness areas to protected summer ranges inside Yellowstone National Park, USA. We attribute this decline to a long-term reduction in the demographic benefits that ungulates typically gain from migration. Among migratory elk, we observed a 21-year, 70% reduction in recruitment and a 4-year, 19% depression in their pregnancy rate largely caused by infrequent reproduction of females that were young or lactating. In contrast, among resident elk, we have recently observed increasing recruitment and a high rate of pregnancy. Landscape-level changes in habitat quality and predation appear to be responsible for the declining productivity of Yellowstone migrants. From 1989 to 2009, migratory elk experienced an increasing rate and shorter duration of green-up coincident with warmer spring-summer temperatures and reduced spring precipitation, also consistent with observations of an unusually severe drought in the region. Migrants are also now exposed to four times as many grizzly bears (Ursus arctos) and wolves (Canis lupus) as resident elk. Both of these restored predators consume migratory elk calves at high rates in the Yellowstone wilderness but are maintained at low densities via lethal management and human disturbance in the year-round habitats of resident elk. Our findings suggest that large-carnivore recovery and drought, operating simultaneously along an elevation gradient, have disproportionately influenced the demography of migratory elk. Many migratory animals travel large geographic distances between their seasonal ranges. Changes in land use and climate that disparately influence
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Genetic engineering of human NK cells to express CXCR2 improves migration to renal cell carcinoma.
Kremer, Veronika; Ligtenberg, Maarten A; Zendehdel, Rosa; Seitz, Christina; Duivenvoorden, Annet; Wennerberg, Erik; Colón, Eugenia; Scherman-Plogell, Ann-Helén; Lundqvist, Andreas
2017-09-19
Adoptive natural killer (NK) cell transfer is being increasingly used as cancer treatment. However, clinical responses have so far been limited to patients with hematological malignancies. A potential limiting factor in patients with solid tumors is defective homing of the infused NK cells to the tumor site. Chemokines regulate the migration of leukocytes expressing corresponding chemokine receptors. Various solid tumors, including renal cell carcinoma (RCC), readily secrete ligands for the chemokine receptor CXCR2. We hypothesize that infusion of NK cells expressing high levels of the CXCR2 chemokine receptor will result in increased influx of the transferred NK cells into tumors, and improved clinical outcome in patients with cancer. Blood and tumor biopsies from 14 primary RCC patients were assessed by flow cytometry and chemokine analysis. Primary NK cells were transduced with human CXCR2 using a retroviral system. CXCR2 receptor functionality was determined by Calcium flux and NK cell migration was evaluated in transwell assays. We detected higher concentrations of CXCR2 ligands in tumors compared with plasma of RCC patients. In addition, CXCL5 levels correlated with the intratumoral infiltration of CXCR2-positive NK cells. However, tumor-infiltrating NK cells from RCC patients expressed lower CXCR2 compared with peripheral blood NK cells. Moreover, healthy donor NK cells rapidly lost their CXCR2 expression upon in vitro culture and expansion. Genetic modification of human primary NK cells to re-express CXCR2 improved their ability to specifically migrate along a chemokine gradient of recombinant CXCR2 ligands or RCC tumor supernatants compared with controls. The enhanced trafficking resulted in increased killing of target cells. In addition, while their functionality remained unchanged compared with control NK cells, CXCR2-transduced NK cells obtained increased adhesion properties and formed more conjugates with target cells. To increase the success of NK
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Reprogramming hMSCs morphology with silicon/porous silicon geometric micro-patterns.
Ynsa, M D; Dang, Z Y; Manso-Silvan, M; Song, J; Azimi, S; Wu, J F; Liang, H D; Torres-Costa, V; Punzon-Quijorna, E; Breese, M B H; Garcia-Ruiz, J P
2014-04-01
Geometric micro-patterned surfaces of silicon combined with porous silicon (Si/PSi) have been manufactured to study the behaviour of human Mesenchymal Stem Cells (hMSCs). These micro-patterns consist of regular silicon hexagons surrounded by spaced columns of silicon equilateral triangles separated by PSi. The results show that, at an early culture stage, the hMSCs resemble quiescent cells on the central hexagons with centered nuclei and actin/β-catenin and a microtubules network denoting cell adhesion. After 2 days, hMSCs adapted their morphology and cytoskeleton proteins from cell-cell dominant interactions at the center of the hexagonal surface. This was followed by an intermediate zone with some external actin fibres/β-catenin interactions and an outer zone where the dominant interactions are cell-silicon. Cells move into silicon columns to divide, migrate and communicate. Furthermore, results show that Runx2 and vitamin D receptors, both specific transcription factors for skeleton-derived cells, are expressed in cells grown on micropatterned silicon under all observed circumstances. On the other hand, non-phenotypic alterations are under cell growth and migration on Si/PSi substrates. The former consideration strongly supports the use of micro-patterned silicon surfaces to address pending questions about the mechanisms of human bone biogenesis/pathogenesis and the study of bone scaffolds.
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Alghanem, Ahmad F; Wilkinson, Emma L; Emmett, Maxine S; Aljasir, Mohammad A; Holmes, Katherine; Rothermel, Beverley A; Simms, Victoria A; Heath, Victoria L; Cross, Michael J
2017-08-01
Regulator of calcineurin 1 (RCAN1) is an endogenous inhibitor of the calcineurin pathway in cells. It is expressed as two isoforms in vertebrates: RCAN1.1 is constitutively expressed in most tissues, whereas transcription of RCAN1.4 is induced by several stimuli that activate the calcineurin-NFAT pathway. RCAN1.4 is highly upregulated in response to VEGF in human endothelial cells in contrast to RCAN1.1 and is essential for efficient endothelial cell migration and tubular morphogenesis. Here, we show that RCAN1.4 has a role in the regulation of agonist-stimulated VEGFR-2 internalisation and establishment of endothelial cell polarity. siRNA-mediated gene silencing revealed that RCAN1 plays a vital role in regulating VEGF-mediated cytoskeletal reorganisation and directed cell migration and sprouting angiogenesis. Adenoviral-mediated overexpression of RCAN1.4 resulted in increased endothelial cell migration. Antisense-mediated morpholino silencing of the zebrafish RCAN1.4 orthologue revealed a disrupted vascular development further confirming a role for the RCAN1.4 isoform in regulating vascular endothelial cell physiology. Our data suggest that RCAN1.4 plays a novel role in regulating endothelial cell migration by establishing endothelial cell polarity in response to VEGF.
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Smoothing internal migration age profiles for comparative research
Directory of Open Access Journals (Sweden)
Aude Bernard
2015-05-01
Full Text Available Background: Age patterns are a key dimension to compare migration between countries and over time. Comparative metrics can be reliably computed only if data capture the underlying age distribution of migration. Model schedules, the prevailing smoothing method, fit a composite exponential function, but are sensitive to function selection and initial parameter setting. Although non-parametric alternatives exist, their performance is yet to be established. Objective: We compare cubic splines and kernel regressions against model schedules by assessingwhich method provides an accurate representation of the age profile and best performs on metrics for comparing aggregate age patterns. Methods: We use full population microdata for Chile to perform 1,000 Monte-Carlo simulations for nine sample sizes and two spatial scales. We use residual and graphic analysis to assess model performance on the age and intensity at which migration peaks and the evolution of migration age patterns. Results: Model schedules generate a better fit when (1 the expected distribution of the age profile is known a priori, (2 the pre-determined shape of the model schedule adequately describes the true age distribution, and (3 the component curves and initial parameter values can be correctly set. When any of these conditions is not met, kernel regressions and cubic splines offer more reliable alternatives. Conclusions: Smoothing models should be selected according to research aims, age profile characteristics, and sample size. Kernel regressions and cubic splines enable a precise representation of aggregate migration age profiles for most sample sizes, without requiring parameter setting or imposing a pre-determined distribution, and therefore facilitate objective comparison.
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Vanasse, Alain; Ricketts, Thomas C; Courteau, Josiane; Orzanco, Maria Gabriela; Randolph, R; Asghari, Shabnam
2007-01-01
The geographic distribution of physicians in the United States of America has been often described as unbalanced or maldistributed. There is much in the literature on the regional distribution of physicians but far less is written about their pattern of movement. This study aimed to examine the geographic transition of physicians at two points in time (1981 and 2003), in and out the four US census regions (Northeast, Midwest, South, and West). We identified 83 383 non-federal clinically active primary care physicians (CAPCP) who were clinically active both in 1981 and in 2003 as registered in the American Medical Association Physician Masterfiles. The main variable was the migration status observed between 1981 and 2003, and they were categorized into three groups: (1) non-migrants (same county of practice); (2) internal migrants (different counties of practice, same region); or (3) external migrants (different regions of practice). Covariables were gender and age for the CAPCP, and the percentage of non-whites in the population, the mean per capita income of the population, the ratio of primary care physicians and the ratio of hospital beds per 1000 inhabitants, as well as the rural/urban status for the county of practice in 1981 (large metropolitan area, small metropolitan area, or non-adjacent). Overall, 13.2 % of CAPCP moved from one region to another between 1981 and 2003. Women and young CAPCPs were more prone to migrate during their career. Proportionally, a greater outflow of the 1981 workforce is observed for the Northeast and Midwest regions with 16% and 18%, respectively, compared with 10% for both the West and South regions. When taking into account the total flow (in and out) for each region, the West and the South 'benefited' from CAPCPs' migration, with respectively a 1.10 and 1.07 increase in 2003 when compared with 1981; while the Midwest and the Northeast regions ended with a 0.90 and 0.92 decrease in 2003. Both logistic regression and regression
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Zehender, Gianguglielmo; Frati, Elena Rosanna; Martinelli, Marianna; Bianchi, Silvia; Amendola, Antonella; Ebranati, Erika; Ciccozzi, Massimo; Galli, Massimo; Lai, Alessia; Tanzi, Elisabetta
2016-04-01
A major limitation when reconstructing the origin and evolution of HPV-16 is the lack of reliable substitution rate estimates for the viral genes. On the basis of the hypothesis of human HPV-16 co-divergence, we estimated a mean evolutionary rate of 1.47×10(-7) (95% HPD=0.64-2.47×10(-7)) subs/site/year for the viral LCR region. The results of a Bayesian phylogeographical analysis suggest that the currently circulating HPV-16 most probably originated in Africa about 110 thousand years ago (Kya), before giving rise to four known geographical lineages: the Asian/European lineage, which most probably originated in Asia a mean 38 Kya, and the Asian/American and two African lineages, which probably respectively originated about 33 and 27 Kya. These data closely reflect current hypotheses concerning modern human expansion based on studies of mitochondrial DNA phylogeny. The correlation between ancient human migration and the present HPV phylogeny may be explained by the co-existence of modes of transmission other than sexual transmission. Copyright © 2016. Published by Elsevier B.V.
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Expression pattern of thymosin beta 4 in the adult human liver
Directory of Open Access Journals (Sweden)
S. Nemolato
2011-09-01
Full Text Available Thymosin beta-4 (Tβ4 is a member of beta-thymosins, a family of small peptides involved in polymerization of G-actin, and in many critical biological processes including apoptosis, cell migration, angiogenesis, and fibrosis. Previous studies in the newborn liver did not reveal any significant reactivity for Tβ4 during the intrauterine life. The aim of the present study was to investigate by immunohistochemistry Tβ4 expression in the adult normal liver. Thirty-five human liver samples, including 11 needle liver biopsies and 24 liver specimens obtained at autopsy, in which no pathological change was detected at the histological examination, were immunostained utilizing an anti-Tβ4 commercial antibody. Tβ4 was detected in the hepatocytes of all adult normal livers examined. A zonation of Tβ4 expression was evident in the vast majority of cases. Immunostaining was preferentially detected in zone 3, while a minor degree of reactivity was detected in periportal hepatocytes (zone 1. At higher power, Tβ4-reactive granules appeared mainly localized at the biliary pole of hepatocytes. In cases with a strong immunostaining, even perinuclear areas and the sinusoidal pole of hepatocytes appeared interested by immunoreactivity for Tβ4. The current work first evidences a strong diffuse expression of Tβ4 in the adult human liver, and adds hepatocytes to the list of human cells able to synthesize large amounts of Tβ4 in adulthood. Moreover, Tβ4 should be added to the liver proteins characterized by a zonate expression pattern, in a descending gradient from the terminal vein to the periportal areas of the liver acinus. Identifying the intimate role played by this peptide intracellularly and extracellularly, in physiology and in different liver diseases, is a major challenge for future research focusing on Tβ4.
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2013-01-01
Chemokine (C-C motif) ligand 3 (CCL3), also known as macrophage inflammatory protein-1α, is a cytokine involved in inflammation and activation of polymorphonuclear leukocytes. CCL3 has been detected in infiltrating cells and tumor cells. Chondrosarcoma is a highly malignant tumor that causes distant metastasis. However, the effect of CCL3 on human chondrosarcoma metastasis is still unknown. Here, we found that CCL3 increased cellular migration and expression of matrix metalloproteinase (MMP)-2 in human chondrosarcoma cells. Pre-treatment of cells with the MMP-2 inhibitor or transfection with MMP-2 specific siRNA abolished CCL3-induced cell migration. CCL3 has been reported to exert its effects through activation of its specific receptor, CC chemokine receptor 5 (CCR5). The CCR5 and AMP-activated protein kinase (AMPK) inhibitor or siRNA also attenuated CCL3-upregulated cell motility and MMP-2 expression. CCL3-induced expression of MMP-2 and migration were also inhibited by specific inhibitors, and inactive mutants of AMPK, p38 mitogen activated protein kinase (p38 or p38-MAPK), and nuclear factor κB (NF-κB) cascades. On the other hand, CCL3 treatment demonstrably activated AMPK, p38, and NF-κB signaling pathways. Furthermore, the expression levels of CCL3, CCR5, and MMP-2 were correlated in human chondrosarcoma specimens. Taken together, our results indicate that CCL3 enhances the migratory ability of human chondrosarcoma cells by increasing MMP-2 expression via the CCR5, AMPK, p38, and NF-κB pathways. PMID:24047437
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Xu, Yanjie; Gong, Peng; Wielstra, Ben; Si, Yali
2016-01-01
The highly pathogenic avian influenza subtype H5N1 (HPAI H5N1) is a worldwide zoonotic infectious disease, threatening humans, poultry and wild birds. The role of wild birds in the spread of HPAI H5N1 has previously been investigated by comparing disease spread patterns with bird migration
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Migration patterns of post-spawning Pacific herring in a subarctic sound
Bishop, Mary Anne; Eiler, John H.
2018-01-01
Understanding the distribution of Pacific herring (Clupea pallasii) can be challenging because spawning, feeding and overwintering may take place in different areas separated by 1000s of kilometers. Along the northern Gulf of Alaska, Pacific herring movements after spring spawning are largely unknown. During the fall and spring, herring have been seen moving from the Gulf of Alaska into Prince William Sound, a large embayment, suggesting that fish spawning in the Sound migrate out into the Gulf of Alaska. We acoustic-tagged 69 adult herring on spawning grounds in Prince William Sound during April 2013 to determine seasonal migratory patterns. We monitored departures from the spawning grounds as well as herring arrivals and movements between the major entrances connecting Prince William Sound and the Gulf of Alaska. Departures of herring from the spawning grounds coincided with cessation of major spawning events in the immediate area. After spawning, 43 of 69 tagged herring (62%) moved to the entrances of Prince William Sound over a span of 104 d, although most fish arrived within 10 d of their departure from the spawning grounds. A large proportion remained in these areas until mid-June, most likely foraging on the seasonal bloom of large, Neocalanus copepods. Pulses of tagged herring detected during September and October at Montague Strait suggest that some herring returned from the Gulf of Alaska. Intermittent detections at Montague Strait and the Port Bainbridge passages from September through early January (when the transmitters expired) indicate that herring schools are highly mobile and are overwintering in this area. The pattern of detections at the entrances to Prince William Sound suggest that some herring remain in the Gulf of Alaska until late winter. The results of this study confirm the connectivity between local herring stocks in Prince William Sound and the Gulf of Alaska.
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Directory of Open Access Journals (Sweden)
Shumei Man
2008-01-01
Full Text Available Endothelial cells that functionally express blood brain barrier (BBB properties are useful surrogates for studying leukocyte-endothelial cell interactions at the BBB. In this study, we compared two different endothelial cellular models: transfected human brain microvascular endothelial cells (THBMECs and human umbilical vein endothelial cells (HUVECs. With each grow under optimal conditions, confluent THBMEC cultures showed continuous occludin and ZO-1 immunoreactivity, while HUVEC cultures exhibited punctate ZO-1 expression at sites of cell-cell contact only. Confluent THBMEC cultures on 24-well collagen-coated transwell inserts had significantly higher transendothelial electrical resistance (TEER and lower solute permeability than HUVECs. Confluent THBMECs were more restrictive for mononuclear cell migration than HUVECs. Only THBMECs utilized abluminal CCL5 to facilitate T-lymphocyte migration in vitro although both THBMECs and HUVECs employed CCL3 to facilitate T cell migration. These data establish baseline conditions for using THBMECs to develop in vitro BBB models for studying leukocyte-endothelial interactions during neuroinflammation.
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Chen, Wenbo; Doko, Tomoko; Fujita, Go; Hijikata, Naoya; Tokita, Ken-Ichi; Uchida, Kiyoshi; Konishi, Kan; Hiraoka, Emiko; Higuchi, Hiroyoshi
2016-02-01
Migration through the Eastern Palearctic (EP) flyway by tundra swans (Cygnus columbianus) has not been thoroughly documented. We satellite-tracked the migration of 16 tundra swans that winter in Japan. The objectives of this study were 1) to show the migration pattern of the EP flyway of tundra swans; 2) to compare this pattern with the migration pattern of whooper swans; and 3) to identify stopover sites that are important for these swans' conservation. Tundra swans were captured at Kutcharo Lake, Hokkaido, in 2009-2012 and satellite-tracked. A new method called the "MATCHED (Migratory Analytical Time Change Easy Detection) method" was developed. Based on median, the spring migration began on 18 April and ended on 27 May. Autumn migration began on 9 September and ended on 2 November. The median duration of the spring and autumn migrations were 48 and 50 days, respectively. The mean duration at one stopover site was 5.5 days and 6.8 days for the spring and autumn migrations, respectively. The number of stopover sites was 3.0 and 2.5 for the spring and autumn migrations, respectively. The mean travel distances for the spring and autumn migrations were 6471 and 6331 km, respectively. Seven migration routes passing Sakhalin, the Amur River, and/or Kamchatka were identified. There were 15, 32, and eight wintering, stopover, and breeding sites, respectively. The migration routes and staging areas of tundra swans partially overlap with those of whooper swans, whose migration patterns have been previously documented. The migration patterns of these two swan species that winter in Japan confirm the importance of the Amur River, Udyl' Lake, Shchastya Bay, Aniva Bay, zaliv Chayvo Lake, zal Piltun Lake, zaliv Baykal Lake, Kolyma River, Buyunda River, Sen-kyuyel' Lake, and northern coastal areas of the Sea of Okhotsk.
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The Phasing-Out of 18th-Century Patterns of German Migration to the United States after 1817
Directory of Open Access Journals (Sweden)
Hans-Jürgen Grabbe
2017-07-01
Full Text Available The years 1816 to 1819, at the beginning of the 19th century, saw the last wave of immigration into the United States that basically followed patterns of travel, finance, and trade established in the 1700s. Migrants from the German-speaking areas of Central Europe, in particular, reached British North America and later the United States under arrangements allowing them to book a passage on credit which they were to pay off by entering into a term of service for room and board which generally lasted from three to seven years. Their debt was redeemed this way, and such migrants were known as redemptioners. The contract agreement consisted of an original and a copy. When separating the two, the upper margins became indented—hence the term indentured servant. The reasons for the disappearance of this major 18th-century migration pattern, caused, above all, by the collapse of the redemptioner system, will be the focus of this article.
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Migration characterization of Ga and In adatoms on dielectric surface in selective MOVPE
International Nuclear Information System (INIS)
Chen Wei-Jie; Han Xiao-Biao; Lin Jia-Li; Hu Guo-Heng; Liu Ming-Gang; Yang Yi-Bin; Chen Jie; Wu Zhi-Sheng; Zhang Bai-Jun; Liu Yang
2015-01-01
Migration characterizations of Ga and In adatoms on the dielectric surface in selective metal organic vapor phase epitaxy (MOVPE) were investigated. In the typical MOVPE environment, the selectivity of growth is preserved for GaN, and the growth rate of GaN micro-pyramids is sensitive to the period of the patterned SiO 2 mask. A surface migration induced model was adopted to figure out the effective migration length of Ga adatoms on the dielectric surface. Different from the growth of GaN, the selective area growth of InGaN on the patterned template would induce the deposition of InGaN polycrystalline particles on the patterned SiO 2 mask with a long period. It was demonstrated with a scanning electron microscope and energy dispersive spectroscopy that the In adatoms exhibit a shorter migration length on the dielectric surface. (paper)
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Yang, Yongliang; Jamilpour, Nima; Yao, Baoyin; Dean, Zachary S; Riahi, Reza; Wong, Pak Kin
2016-03-03
When blood vessels are injured, leader cells emerge in the endothelium to heal the wound and restore the vasculature integrity. The characteristics of leader cells during endothelial collective migration under diverse physiological conditions, however, are poorly understood. Here we investigate the regulation and function of endothelial leader cells by plasma lithography geometric confinement generated. Endothelial leader cells display an aggressive phenotype, connect to follower cells via peripheral actin cables and discontinuous adherens junctions, and lead migrating clusters near the leading edge. Time-lapse microscopy, immunostaining, and particle image velocimetry reveal that the density of leader cells and the speed of migrating clusters are tightly regulated in a wide range of geometric patterns. By challenging the cells with converging, diverging and competing patterns, we show that the density of leader cells correlates with the size and coherence of the migrating clusters. Collectively, our data provide evidence that leader cells control endothelial collective migration by regualting the migrating clusters.
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Unsworth, C P; Graham, E S; Delivopoulos, E; Dragunow, M; Murray, A F
2010-12-15
In this communication, we describe a new method which has enabled the first patterning of human neurons (derived from the human teratocarcinoma cell line (hNT)) on parylene-C/silicon dioxide substrates. We reveal the details of the nanofabrication processes, cell differentiation and culturing protocols necessary to successfully pattern hNT neurons which are each key aspects of this new method. The benefits in patterning human neurons on silicon chip using an accessible cell line and robust patterning technology are of widespread value. Thus, using a combined technology such as this will facilitate the detailed study of the pathological human brain at both the single cell and network level. Copyright © 2010 Elsevier B.V. All rights reserved.
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Computer-assisted image analysis assay of human neutrophil chemotaxis in vitro
DEFF Research Database (Denmark)
Jensen, P; Kharazmi, A
1991-01-01
We have developed a computer-based image analysis system to measure in-filter migration of human neutrophils in the Boyden chamber. This method is compared with the conventional manual counting techniques. Neutrophils from healthy individuals and from patients with reduced chemotactic activity were....... Another advantage of the assay is that it can be used to show the migration pattern of different populations of neutrophils from both healthy individuals and patients....
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Energy Technology Data Exchange (ETDEWEB)
Kosten, Ilona J.; Spiekstra, Sander W. [Department of Dermatology, VU University Medical Center, Amsterdam (Netherlands); Gruijl, Tanja D. de [Department of Dermatology Medical Oncology, VU University Medical Center, Amsterdam (Netherlands); Gibbs, Susan, E-mail: s.gibbs@acta.nl [Department of Dermatology, VU University Medical Center, Amsterdam (Netherlands); Department of Oral Cell Biology, Academic Center for Dentistry (ACTA), Amsterdam (Netherlands)
2015-08-15
After allergen or irritant exposure, Langerhans cells (LC) undergo phenotypic changes and exit the epidermis. In this study we describe the unique ability of MUTZ-3 derived Langerhans cells (MUTZ-LC) to display similar phenotypic plasticity as their primary counterparts when incorporated into a physiologically relevant full-thickness skin equivalent model (SE-LC). We describe differences and similarities in the mechanisms regulating LC migration and plasticity upon allergen or irritant exposure. The skin equivalent consisted of a reconstructed epidermis containing primary differentiated keratinocytes and CD1a{sup +} MUTZ-LC on a primary fibroblast-populated dermis. Skin equivalents were exposed to a panel of allergens and irritants. Topical exposure to sub-toxic concentrations of allergens (nickel sulfate, resorcinol, cinnamaldehyde) and irritants (Triton X-100, SDS, Tween 80) resulted in LC migration out of the epidermis and into the dermis. Neutralizing antibody to CXCL12 blocked allergen-induced migration, whereas anti-CCL5 blocked irritant-induced migration. In contrast to allergen exposure, irritant exposure resulted in cells within the dermis becoming CD1a{sup −}/CD14{sup +}/CD68{sup +} which is characteristic of a phenotypic switch of MUTZ-LC to a macrophage-like cell in the dermis. This phenotypic switch was blocked with anti-IL-10. Mechanisms previously identified as being involved in LC activation and migration in native human skin could thus be reproduced in the in vitro constructed skin equivalent model containing functional LC. This model therefore provides a unique and relevant research tool to study human LC biology in situ under controlled in vitro conditions, and will provide a powerful tool for hazard identification, testing novel therapeutics and identifying new drug targets. - Highlights: • MUTZ-3 derived Langerhans cells integrated into skin equivalents are fully functional. • Anti-CXCL12 blocks allergen-induced MUTZ-LC migration.
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Mediterranean Migrations: Regionalisms Versus Globalisation
Directory of Open Access Journals (Sweden)
Martin Baldwin-Eduards
2004-06-01
Full Text Available This paper challenges the claim of globalisation as a cause ofimmigration into Southern Europe and, on an empirical basis, identifies regionalisation as being the primary issue, along with networked migratory patterns. However, the changing patterns of immigration do present challenges to both state and society. It is argued here that recent policy responses in Portugal, Italy and Spain have been inconsistent and irrational – reflecting more the ‘securitisation’ of migration than European reality. Earlier policy innovations are identified, by country and date: most of these have now been abandoned. It is suggested that all of Southern Europe has converged onto a statist, restrictionist model of immigration control that was formerly held only by Greece. The principal characteristics of this model are outlined, along with a migration flowchart and indicative data for migrant flows and sub-flows in Italy and Spain. In the final section, I try to show that the needs of the economy cannot be predicted, immigration cannot becontrolled in the manner currently being enforced across Southern Europe, and attempts to do so will damage rather than improve economic productivity and growth. The concept of an accomodating immigration policy is advanced, whereby the state tries to manage the needs of both employers and potential migrants. Six guidelines for policy development are suggested – most of which have alreadybeen successfully carried out in the European Union. These are the following: migration in order to find a job; circular cross-border migration; EU level negotiation of readmission agreements; the need for a variety of migration-for-employment schemes; legal residence should not depend upon continuity of employment; and discreet legalisation will still be needed in Southern Europe.
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Moving across boundaries: migration in South Africa, 1950-2000.
Reed, Holly E
2013-02-01
Existing knowledge about historical patterns of black internal migration in South Africa is incomplete, primarily because of the lack of good life course studies as well as the apartheid government's suppression and censoring of data. This article provides a comprehensive picture of historical internal migration patterns with an analysis of a unique individual retrospective life history data set. This sample of the black population, collected in 2000, is the only known nationally representative life history data for South Africa; it includes all residential moves for each individual during his/her lifetime. Various mobility outcomes are analyzed: moves within/across provinces, moves within/across rural and urban areas, forced moves, moves with a nuclear family, and individual moves. The results indicate that migration significantly increased among black South Africans during the last half of the twentieth century, and that this increase began before the Pass Laws were repealed in 1986 and well before the official end of apartheid in 1991 or the first free election in 1994. The timing of this increase in migration rates suggests that migration in defiance of the Pass Laws (albeit a dangerous and desperate proposition) was a way of life for many black South Africans.
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a Three-Step Spatial-Temporal Clustering Method for Human Activity Pattern Analysis
Huang, W.; Li, S.; Xu, S.
2016-06-01
How people move in cities and what they do in various locations at different times form human activity patterns. Human activity pattern plays a key role in in urban planning, traffic forecasting, public health and safety, emergency response, friend recommendation, and so on. Therefore, scholars from different fields, such as social science, geography, transportation, physics and computer science, have made great efforts in modelling and analysing human activity patterns or human mobility patterns. One of the essential tasks in such studies is to find the locations or places where individuals stay to perform some kind of activities before further activity pattern analysis. In the era of Big Data, the emerging of social media along with wearable devices enables human activity data to be collected more easily and efficiently. Furthermore, the dimension of the accessible human activity data has been extended from two to three (space or space-time) to four dimensions (space, time and semantics). More specifically, not only a location and time that people stay and spend are collected, but also what people "say" for in a location at a time can be obtained. The characteristics of these datasets shed new light on the analysis of human mobility, where some of new methodologies should be accordingly developed to handle them. Traditional methods such as neural networks, statistics and clustering have been applied to study human activity patterns using geosocial media data. Among them, clustering methods have been widely used to analyse spatiotemporal patterns. However, to our best knowledge, few of clustering algorithms are specifically developed for handling the datasets that contain spatial, temporal and semantic aspects all together. In this work, we propose a three-step human activity clustering method based on space, time and semantics to fill this gap. One-year Twitter data, posted in Toronto, Canada, is used to test the clustering-based method. The results show that the
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Directory of Open Access Journals (Sweden)
Qiaoyun Zhou
Full Text Available OBJECTIVE: Melatonin, an indolamine produced and secreted predominately by the pineal gland, exhibits a variety of physiological functions, possesses antioxidant and antitumor properties. But, the mechanisms for the anti-cancer effects are unknown. The present study explored the effects of melatonin on the migration of human lung adenocarcinoma A549 cells and its mechanism. METHODS: MTT assay was employed to measure the viability of A549 cells treated with different concentrations of melatonin. The effect of melatonin on the migration of A549 cells was analyzed by wound healing assay. Occludin location was observed by immunofluorescence. The expression of occludin, osteopontin (OPN, myosin light chain kinase (MLCK and phosphorylation of myosin light chain (MLC, JNK were detected by western blots. RESULTS: After A549 cells were treated with melatonin, the viability and migration of the cells were inhibited significantly. The relative migration rate of A549 cells treated with melatonin was only about 20% at 24 h. The expression level of OPN, MLCK and phosphorylation of MLC of A549 cells were reduced, while the expression of occludin was conversely elevated, and occludin located on the cell surface was obviously increased. The phosphorylation status of JNK in A549 cells was also reduced when cells were treated by melatonin. CONCLUSIONS: Melatonin significantly inhibits the migration of A549 cells, and this may be associated with the down-regulation of the expression of OPN, MLCK, phosphorylation of MLC, and up-regulation of the expression of occludin involving JNK/MAPK pathway.
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Why Migrate: For Study or for Work?
Directory of Open Access Journals (Sweden)
Elise S. Brezis
2016-08-01
Full Text Available Over the past decades, globalization has led to a huge increase in the migration of workers, as well as students. This paper develops a simple two-step model that describes the decisions of an individual vis-à-vis education and migration, and presents a unified model, wherein the two migration decisions are combined into a single, unique model. This paper shows that under the plausible assumption that costs of migration differ over the human life cycle, the usual brain drain strategy is sub-optimal. With an increase in globalization, the brain drain strategy will be replaced by the strategy of migration of students.
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International migration: a global challenge.
Martin, P; Widgren, J
1996-04-01
Trends in international migration are presented in this multiregional analysis. Seven of the world's wealthiest countries have about 33% of the world's migrant population, but under 16% of the total world population. Population growth in these countries is substantially affected by the migrant population. The migration challenge is external and internal. The external challenge is to balance the need for foreign labor and the commitment to human rights for those migrants seeking economic opportunity and political freedom. The internal challenge is to assure the social adjustment of immigrants and their children and to integrate them into society as citizens and future leaders. Why people cross national borders and how migration flows are likely to evolve over the next decades are explained. This report also presents some ways that countries can manage migration or reduce the pressures which force people to migrate. It is recommended that receiving nations control immigration by accelerating global economic growth and reducing wars and human rights violations. This report examines the impact of immigration on international trade, aid, and direct intervention policies. Although migration is one of the most important international economic issues, it is not coordinated by an international group. The European experience indicates that it is not easy to secure international cooperation on issues that affect national sovereignty. It is suggested that countries desiring control of their borders should remember that most people never cross national borders to live or work in another country, that 50% of the world's migrants move among developing countries, and that countries can shift from being emigration to immigration countries. The author suggests that sustained reductions in migration pressure are a better alternative than the "quick fixes" that may invite the very much feared mass and unpredictable movements.
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Wang, Beilei; Liu, Jinghui; Huang, Pu; Xu, Kailun; Wang, Hanying; Wang, Xiaofeng; Guo, Zonglou; Xu, Lihong
2017-03-01
The major toxic mechanism of Microcystin-LR is inhibition of the activity of protein phosphatase 2A (PP2A), resulting in a series of cytotoxic effects. Our previous studies have demonstrated that microcystin-LR (MCLR) induced very different molecular effects in normal cells and the tumor cell line SMMC7721. To further explore the MCLR toxicity mechanism in tumor cells, human laryngeal epithelial cells (Hep-2) was examined in this study. Western blot, immunofluorescence, immunoprecipitation, and transwell migration assay were used to detect the effects of MCLR on PP2A activity, PP2A substrates, cytoskeleton, and cell migration. The results showed that the protein level of PP2A subunits and the posttranslational modification of the catalytic subunit were altered and that the binding of the AC core enzyme as well as the binding of PP2A/C and α4, was also affected. As PP2A substrates, the phosphorylation of MAPK pathway members, p38, ERK1/2, and the cytoskeleton-associated proteins, Hsp27, VASP, Tau, and Ezrin were increased. Furthermore, MCLR induced reorganization of the cytoskeleton and promoted cell migration. Taken together, direct covalent binding to PP2A/C, alteration of the protein levels and posttranslational modification, as well as the binding of subunits, are the main pattern for the effects of MCLR on PP2A in Hep-2. A dose-dependent change in p-Tau and p-Ezrin due to PP2A inhibition may contribute to the changes in the cytoskeleton and be related to the cell migration in Hep-2. Our data provide a comprehensive exposition of the MCLR mechanism on tumor cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 890-903, 2017. © 2016 Wiley Periodicals, Inc.
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QUALIFIED VERSION OF MIGRATION: BRAIN DRAIN
Directory of Open Access Journals (Sweden)
Ayhan GENCLER
2009-07-01
Full Text Available Though globalization suggests an international exchange of people besides goods and capital, developed countries often tended to put forward some restrictions on the migration of workers from developed countries. However, there has been an increase in skilled international migration especially during the last two decades. Skilled international migration or brain drain points out the emigration of educated and highly skilled workers. It seems that, in general, developing or underdeveloped countries experience the negative consequences of the brain drain and suffer from the decreases in their human capital. The paper explains the phenomenon of skilled international migration, or brain drain, and summarizes the main global trends in this area.
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Self-selection and intermunicipal migration in Canada.
Islam, M N; Choudhury, S A
1991-02-01
"This paper investigates individual intermunicipal migration behaviour in Canada within the context of a human capital model that adjusts for the migrant's selectivity in computing expected income gains. In addition to the typical regional determinants of migration, housing and labour market characteristics are found to influence intermunicipal migration significantly, the effects differing with age. Structural coefficients remained more or less stable during the decade 1971-1981. It is shown that the failure to adjust income gains for selectivity bias results in an underestimation of the migration-impacts of income gains and municipal-specific factors." excerpt
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Geography of spring landbird migration through riparian habitats in southwestern North America
Susan K. Skagen; Jeffrey F. Kelly; Charles van Riper III; Richard L. Hutto; Deborah M. Finch; David J. Krueper; Cynthia P. Melcher
2005-01-01
Migration stopover resources, particularly riparian habitats, are critically important to landbirds migrating across the arid southwestern region of North America. To explore the effects of species biogeography and habitat affinity on spring migration patterns, we synthesized existing bird abundance and capture data collected in riparian habitats of the borderlands...
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Challenging issues in the study of fiscally-induced migration.
Winer, S L
1986-01-01
This paper reviews Shaw's book, INTERMETROPOLITAN MIGRATION IN CANADA, which provides new evidence concerning the link between fiscal structure and internal migration. Shaw bases his work on a valuable new migration series he has put together from census data: intermetropolitan flows from 1956-1981. The existence of censua data at 5-year intervals permits Shaw enough data to estimate migration equations separately for the periods before and after 1971. A comparison of the role of fiscal variables before and after 1971 is interesting because unemployment insurance, equalization payments, and provincial natural resource revenues probably became more important in determining regional differences in incomes after 1971 than in the 20 years prior to that. Shaw suspects that migration behavior has become less sensitive to traditional market variables such as wage differentials and more sensitive to other factors, including quality of life indicators since 1950. The author thinks that Shaw's conclusion cannot rest comfortably on estimating equations that omit fiscal variables. The overall role of wage differentials in determining observed migration patterns is the product of the coefficient on wage variables and the actual evolution of wages over the estimation period. Another problem with the methodology used to contrast pre- and post-1971 migration equations is the apparent neglect of statistical testing for shifts in coefficients on the traditional economic variables and for shifts in the coefficients on the fiscal variables. The strongest of the useful results from the study concern the role of unemployment insurance. The evidence that these have an influence on internal migration is now compelling. Shaw's book adds substantial weight to the view that variation in fiscal structure plays a significant role in determining internal migration patterns.
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Vineetha, G.; Jyothibabu, R.; Madhu, N. V.; Kusum, K. K.; Sooria, P. M.; Shivaprasad, A.; Reny, P. D.; Deepak, M. P.
2015-01-01
in the tidal cycles, which differed from the general concepts of downward migration during ebb tide and upward migration during flood tide in estuarine systems. The weak currents during the slack period might have favored the effective vertical migration
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Dynamic Quantification of Host Schwann Cell Migration into Peripheral Nerve Allografts
Whitlock, Elizabeth L.; Myckatyn, Terence M.; Tong, Alice Y.; Yee, Andrew; Yan, Ying; Magill, Christina K.; Johnson, Philip J.; Mackinnon, Susan E.
2010-01-01
Host Schwann cell (SC) migration into nerve allografts is the limiting factor in the duration of immunosuppression following peripheral nerve allotransplantation, and may be affected by different immunosuppressive regimens. Our objective was to compare SC migration patterns between clinical and experimental immunosuppression regimens both over time and at the harvest endpoint. Eighty mice that express GFP under the control of the Schwann cell specific S100 promoter were engrafted with allogeneic, nonfluorescent sciatic nerve grafts. Mice received immunosuppression with either tacrolimus (FK506), or experimental T-cell triple costimulation blockade (CSB), consisting of CTLA4-immunoglobulin fusion protein, anti-CD40 monoclonal antibody, and anti-inducible costimulator monoclonal antibody. Migration of GFP-expressing host SCs into wild-type allografts was assessed in vivo every 3 weeks until 15 weeks postoperatively, and explanted allografts were evaluated for immunohistochemical staining patterns to differentiate graft from host SCs. Immunosuppression with tacrolimus exhibited a plateau of SC migration, characterized by significant early migration (< 3 weeks) followed by a constant level of host SCs in the graft (15 weeks). At the endpoint, graft fluorescence was decreased relative to surrounding host nerve, and donor SCs persisted within the graft. CSB-treated mice displayed gradually increasing migration of host SCs into the graft, without the plateau noted in tacrolimus-treated mice, and also maintained a population of donor SCs at the 15-week endpoint. SC migration patterns are affected by immunosuppressant choice, particularly in the immediate postoperative period, and the use of a single treatment of CSB may allow for gradual population of nerve allografts with host SCs. PMID:20633557
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International migration and related policies in europe 1950 - 2015
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Penninx Rinus
2016-01-01
Full Text Available Immigration in Europe has been shaped by: a its particular development in time; b the geographical patterns of migration within and towards European countries; and c the shifting types of migration and characteristics of migrants involved. The first part of this contribution outlines changes in these three basic migration-related factors. Migration outcomes are not haphazard nor are these the result of unhindered economic push and pull factors in a free market. Immigration policies of receiving countries do greatly influence the volume and patterns of migration, the place of settlement and the characteristics of migrants. Regulations on conditions of residence and integration do furthermore influence significantly the position of immigrants in their new destination, among others by setting conditions for their stay (residence rights and access to the labour market. The second part of this chapter outlines the migration and integration regimes that have been developed by states of different parts of Europe and by the European Union. In conclusion, immigration has become a relevant phenomenon in all EU countries. However, as a consequence of different timing of immigration, different socio-economic contexts and varying governmental migration and integration policies, European countries are confronted with different forms migration (immigration, emigration, transit migration and with different types of migrants. European states have also developed different governmental policies of migration and integration. Historically, a common denominator in the framing of European policies is that countries do not see themselves as immigration countries; they are immigration countries against their will. In recent times, such framing is reinforced by populist and nationalist movements that see immigrants not only as economic competitors, but also as a threat to the national "culture and world views". The more Europe needs immigrants for economic and
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Migration patterns and wintering range of common loons breeding in the Northeastern United States
Kenow, K.P.; Adams, D.; Schoch, N.; Evers, D.C.; Hanson, W.; Yates, D.; Savoy, L.; Fox, T.J.; Major, A.; Kratt, R.; Ozard, J.
2009-01-01
A study, using satellite telemetry, was conducted to determine the precise migration patterns and wintering locations of Common Loons (Gavia immer) breeding in the northeastern United States. Transmitters were implanted in 17 loons (16 adults and one juvenile) that were captured on breeding lakes in New York, New Hampshire, and Maine during the summers of 2003, 2004, and 2005. Transmitters from ten of the birds provided adequate location data to document movement to wintering areas. Most adult loons appeared to travel non-stop from breeding lakes, or neighboring lakes (within 15 km), to the Atlantic coast. Adult loons marked in New Hampshire and Maine wintered 152 to 239 km from breeding lakes, along the Maine coast. Adult loons marked in the Adirondack Park of New York wintered along the coasts of Massachusetts (414 km from breeding lake), Rhode Island (362 km), and southern New Jersey (527 km). Most of the loons remained relatively stationary throughout the winter, but the size of individual wintering areas of adult loons ranged from 43 to 1,159 km 2, based on a 95% fixed kernel utilization distribution probability. A juvenile bird from New York made a number of stops at lakes and reservoirs en route to Long Island Sound (325 km from breeding lake). Maximum functional life of transmitters was about 12 months, providing an opportunity to document spring migration movements as well. This work provides essential information for development and implementation of regional Common Loon conservation strategies in the Northeastern U.S.
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Migration, urban population growth and regional disparity in China
Renard, Mary-Françoise; Xu, Zelai; Zhu, Nong
2011-01-01
The main objective of this paper is to study the determinants of city population growth in China during the 1990s', as well as the determinants of migrations towards cities, which constitutes the main source of urban population growth in this period. A second objective is to identify regional differences in the urban growth and migrations, that is, whether urban growth and migration patterns are different between coastal and inland provinces. Additionally, we are interested in the differences...
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Delavari, Maryam; Sønderlund, Anders Larrabee; Mellor, David; Mohebbi, Mohammadreza; Swinburn, Boyd
2015-01-01
While migration from low- to high-income countries is typically associated with weight gain, the obesity risks of migration from middle-income countries are less certain. In addition to changes in behaviours and cultural orientation upon migration, analyses of changes in environments are needed to explain post-migration risks for obesity. The present study examines the interaction between obesity-related environmental factors and the pattern of migrant acculturation in a sample of 152 Iranian immigrants in Victoria, Australia. Weight measurements, demographics, physical activity levels and diet habits were also surveyed. The pattern of acculturation (relative integration, assimilation, separation or marginalization) was not related to body mass index, diet, or physical activity behaviours. Three relevant aspects of participants’ perception of the Australian environment (physically active environments, social pressure to be fit, unhealthy food environments) varied considerably by demographic characteristics, but only one (physically active environments) was related to a pattern of acculturation (assimilation). Overall, this research highlighted a number of key relationships between acculturation and obesity-related environments and behaviours for our study sample. Theoretical models on migration, culture and obesity need to include environmental factors. PMID:25648171
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Superior Pattern Processing is the Essence of the Evolved Human Brain
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Mark eMattson
2014-08-01
Full Text Available Humans have long pondered the nature of their mind/brain and, particularly why its capacities for reasoning, communication and abstract thought are far superior to other species, including closely related anthropoids. This article considers superior pattern processing (SPP as the fundamental basis of most, if not all, unique features of the human brain including intelligence, language, imagination, invention, and the belief in imaginary entities such as ghosts and gods. SPP involves the electrochemical, neuronal network-based, encoding, integration, and transfer to other individuals of perceived or mentally-fabricated patterns. During human evolution, pattern processing capabilities became increasingly sophisticated as the result of expansion of the cerebral cortex, particularly the prefrontal cortex and regions involved in processing of images. Specific patterns, real or imagined, are reinforced by emotional experiences, indoctrination and even psychedelic drugs. Impaired or dysregulated SPP is fundamental to cognitive and psychiatric disorders. A broader understanding of SPP mechanisms, and their roles in normal and abnormal function of the human brain, may enable the development of interventions that reduce irrational decisions and destructive behaviors.
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Migration: a core public health ethics issue.
Wild, V; Dawson, A
2018-05-01
In this article, we outline the link between migration, public health and ethics. Discussing relevant arguments about migration from the perspective of public health and public health ethics. Critical review of theories and frameworks, case-based analysis and systematic identification and discussion of challenges. Migration is a core issue of public health ethics and must take a case-based approach: seeking to identify the specific ethical dimensions and vulnerabilities in each particular context. Public health as a practice, built upon the core value of justice, requires the protection and promotion of migrants' well-being (even if this produces tension with immigration services). Ethical analysis should take all phases of migration into account: before, during and after transit. We argue that migration policies, at least as they relate to migrants' well-being, should be founded upon a shared humanity, respect for human rights and on the idea that effective public health cannot and should not be confined within the borders and to the citizens of any host country. We make the case for migration to be seen as a core issue of public health ethics. Copyright © 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
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A Multiscale Survival Process for Modeling Human Activity Patterns.
Zhang, Tianyang; Cui, Peng; Song, Chaoming; Zhu, Wenwu; Yang, Shiqiang
2016-01-01
Human activity plays a central role in understanding large-scale social dynamics. It is well documented that individual activity pattern follows bursty dynamics characterized by heavy-tailed interevent time distributions. Here we study a large-scale online chatting dataset consisting of 5,549,570 users, finding that individual activity pattern varies with timescales whereas existing models only approximate empirical observations within a limited timescale. We propose a novel approach that models the intensity rate of an individual triggering an activity. We demonstrate that the model precisely captures corresponding human dynamics across multiple timescales over five orders of magnitudes. Our model also allows extracting the population heterogeneity of activity patterns, characterized by a set of individual-specific ingredients. Integrating our approach with social interactions leads to a wide range of implications.
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Directory of Open Access Journals (Sweden)
Baur Regine
2006-04-01
Full Text Available Abstract Background The significant reduction of angiographic restenosis rates in the ISAR-SWEET study (intracoronary stenting and antithrombotic regimen: is abciximab a superior way to eliminate elevated thrombotic risk in diabetes raises the question of whether abciximab acts on clopidogrel-independent mechanisms in suppressing neointimal hyperplasia. The current study investigates the direct effect of abciximab on ICAM-1 expression, migration and proliferation. Methods ICAM-1: Part I of the study investigates in cytoflow studies the effect of abciximab (0.0002, 0.002, 0.02, 0.2, 2.0, and 20.0 μg/ml on TNF-α induced expression of intercellular adhesion molecule 1 (ICAM-1. Migration: Part II of the study explored the effect of abciximab (0.0002, 0.002, 0.02, 0.2, 2.0, and 20.0 μg/ml on migration of HCMSMC over a period of 24 h. Proliferation: Part III of the study investigated the effect of abciximab (0.0002, 0.002, 0.02, 0.2, 2.0, and 20.0 μg/ml on proliferation of HUVEC, HCAEC, and HCMSMC after an incubation period of 5 days. Results ICAM-1: In human venous endothelial cells (HUVEC, human coronary endothelial cells (HCAEC and human coronary medial smooth muscle cells (HCMSMC no inhibitory or stimulatory effect on expression of ICAM-1 was detected. Migration: After incubation of HCMSMC with abciximab in concentrations of 0.0002 – 2 μg/ml a stimulatory effect on cell migration was detected, statistical significance was achieved after incubation with 0.002 μg/ml (p 1. Conclusion Thus, the anti-restenotic effects of systemically administered abciximab reported in the ISAR-SWEET-study were not caused by a direct inhibitory effect on ICAM-1 expression, migration or proliferation.
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CXCL5 knockdown expression inhibits human bladder cancer T24 cells proliferation and migration
Energy Technology Data Exchange (ETDEWEB)
Zheng, Jiajia [Department of Laboratory Medicine, Peking University Third Hospital, Beijing (China); Zhu, Xi [Department of Urology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing (China); Zhang, Jie, E-mail: zhangjiebjmu@163.com [Department of Laboratory Medicine, Peking University Third Hospital, Beijing (China)
2014-03-28
Highlights: • We first demonstrated CXCL5 is highly expressed in human bladder tumor tissues and cells. • CXCL5 knockdown inhibits proliferation, migration and promotes apoptosis in T24 cells. • CXCL5 knockdown inhibits Snail, PI3K-AKT and ERK1/2 signaling pathways in T24 cells. • CXCL5 is critical for bladder tumor growth and progression. - Abstract: CXCL5 (epithelial neutrophil activating peptide-78) which acts as a potent chemoattractant and activator of neutrophil function was reported to play a multifaceted role in tumorigenesis. To investigate the role of CXCL5 in bladder cancer progression, we examined the CXCL5 expression in bladder cancer tissues by real-time PCR and Western blot, additionally, we used shRNA-mediated silencing to generate stable CXCL5 silenced bladder cancer T24 cells and defined its biological functions. Our results demonstrated that mRNA and protein of CXCL5 is increased in human bladder tumor tissues and cell lines, down-regulation of CXCL5 in T24 cells resulted in significantly decreased cell proliferation, migration and increased cell apoptosis in vitro through Snail, PI3K-AKT and ERK1/2 signaling pathways. These data suggest that CXCL5 is critical for bladder tumor growth and progression, it may represent a potential application in cancer diagnosis and therapy.
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CXCL5 knockdown expression inhibits human bladder cancer T24 cells proliferation and migration
International Nuclear Information System (INIS)
Zheng, Jiajia; Zhu, Xi; Zhang, Jie
2014-01-01
Highlights: • We first demonstrated CXCL5 is highly expressed in human bladder tumor tissues and cells. • CXCL5 knockdown inhibits proliferation, migration and promotes apoptosis in T24 cells. • CXCL5 knockdown inhibits Snail, PI3K-AKT and ERK1/2 signaling pathways in T24 cells. • CXCL5 is critical for bladder tumor growth and progression. - Abstract: CXCL5 (epithelial neutrophil activating peptide-78) which acts as a potent chemoattractant and activator of neutrophil function was reported to play a multifaceted role in tumorigenesis. To investigate the role of CXCL5 in bladder cancer progression, we examined the CXCL5 expression in bladder cancer tissues by real-time PCR and Western blot, additionally, we used shRNA-mediated silencing to generate stable CXCL5 silenced bladder cancer T24 cells and defined its biological functions. Our results demonstrated that mRNA and protein of CXCL5 is increased in human bladder tumor tissues and cell lines, down-regulation of CXCL5 in T24 cells resulted in significantly decreased cell proliferation, migration and increased cell apoptosis in vitro through Snail, PI3K-AKT and ERK1/2 signaling pathways. These data suggest that CXCL5 is critical for bladder tumor growth and progression, it may represent a potential application in cancer diagnosis and therapy
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Mid-term migration analysis of a femoral short-stem prosthesis: a five-year EBRA-FCA-study.
Freitag, Tobias; Fuchs, Michael; Woelfle-Roos, Julia V; Reichel, Heiko; Bieger, Ralf
2018-05-01
The objective of this study was to evaluate the mid-term migration pattern of a femoral short stem. Implant migration of 73 femoral short-stems was assessed by Ein-Bild-Roentgen-Analysis Femoral-Component-Analysis (EBRA-FCA) 5 years after surgery. Migration pattern of the whole group was analysed and compared to the migration pattern of implants "at risk" with a subsidence of more than 1.5 mm 2 years postoperative. Mean axial subsidence was 1.1 mm (-5.0 mm to 1.5 mm) after 60 months. There was a statistical significant axial migration until 2 years postoperative with settling thereafter. 2 years after surgery 18 of 73 Implants were classified "at risk." Nevertheless, all stems showed secondary stabilisation in the following period with no implant failure neither in the group of implants with early stabilisation nor the group with extensive early onset migration. In summary, even in the group of stems with more pronounced early subsidence, delayed settling occurred in all cases. The determination of a threshold of critical early femoral short stem subsidence is necessary because of the differing migration pattern described in this study with delayed settling of the Fitmore stem 2 years postoperatively compared to early settling within the first postoperative year described for conventional stems.
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Random migration processes between two stochastic epidemic centers.
Sazonov, Igor; Kelbert, Mark; Gravenor, Michael B
2016-04-01
We consider the epidemic dynamics in stochastic interacting population centers coupled by random migration. Both the epidemic and the migration processes are modeled by Markov chains. We derive explicit formulae for the probability distribution of the migration process, and explore the dependence of outbreak patterns on initial parameters, population sizes and coupling parameters, using analytical and numerical methods. We show the importance of considering the movement of resident and visitor individuals separately. The mean field approximation for a general migration process is derived and an approximate method that allows the computation of statistical moments for networks with highly populated centers is proposed and tested numerically. Copyright © 2016 Elsevier Inc. All rights reserved.
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Language competition in a population of migrating agents
Lipowska, Dorota; Lipowski, Adam
2017-05-01
Influencing various aspects of human activity, migration is associated also with language formation. To examine the mutual interaction of these processes, we study a Naming Game with migrating agents. The dynamics of the model leads to formation of low-mobility clusters, which turns out to break the symmetry of the model: although the Naming Game remains symmetric, low-mobility languages are favored. High-mobility languages are gradually eliminated from the system, and the dynamics of language formation considerably slows down. Our model is too simple to explain in detail language competition of migrating human communities, but it certainly shows that languages of settlers are favored over nomadic ones.
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SHARPIN Regulates Uropod Detachment in Migrating Lymphocytes
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Jeroen Pouwels
2013-11-01
Full Text Available SHARPIN-deficient mice display a multiorgan chronic inflammatory phenotype suggestive of altered leukocyte migration. We therefore studied the role of SHARPIN in lymphocyte adhesion, polarization, and migration. We found that SHARPIN localizes to the trailing edges (uropods of both mouse and human chemokine-activated lymphocytes migrating on intercellular adhesion molecule-1 (ICAM-1, which is one of the major endothelial ligands for migrating leukocytes. SHARPIN-deficient cells adhere better to ICAM-1 and show highly elongated tails when migrating. The increased tail lifetime in SHARPIN-deficient lymphocytes decreases the migration velocity. The adhesion, migration, and uropod defects in SHARPIN-deficient lymphocytes were rescued by reintroducing SHARPIN into the cells. Mechanistically, we show that SHARPIN interacts directly with lymphocyte-function-associated antigen-1 (LFA-1, a leukocyte counterreceptor for ICAM-1, and inhibits the expression of intermediate and high-affinity forms of LFA-1. Thus, SHARPIN controls lymphocyte migration by endogenously maintaining LFA-1 inactive to allow adjustable detachment of the uropods in polarized cells.
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Energy Technology Data Exchange (ETDEWEB)
Wu, Feng; Jordan, Ashley; Kluz, Thomas [Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987 (United States); Shen, Steven [Center for Health Informatics and Bioinformatics, New York University Langone Medical Center, New York, NY 10016 (United States); Sun, Hong; Cartularo, Laura A. [Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987 (United States); Costa, Max, E-mail: Max.Costa@nyumc.org [Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987 (United States)
2016-02-15
The special AT-rich sequence-binding protein 2 (SATB2) is a protein that binds to the nuclear matrix attachment region of the cell and regulates gene expression by altering chromatin structure. In our previous study, we reported that SATB2 gene expression was induced in human bronchial epithelial BEAS-2B cells transformed by arsenic, chromium, nickel and vanadium. In this study, we show that ectopic expression of SATB2 in the normal human bronchial epithelial cell-line BEAS-2B increased anchorage-independent growth and cell migration, meanwhile, shRNA-mediated knockdown of SATB2 significantly decreased anchorage-independent growth in Ni transformed BEAS-2B cells. RNA sequencing analyses of SATB2 regulated genes revealed the enrichment of those involved in cytoskeleton, cell adhesion and cell-movement pathways. Our evidence supports the hypothesis that SATB2 plays an important role in BEAS-2B cell transformation. - Highlights: • We performed SATB2 overexpression in the BEAS-2B cell line. • We performed SATB2 knockdown in a Ni transformed BEAS-2B cell line. • SATB2 induced anchorage-independent growth and increased cell migration. • SATB2 knockdown significantly decreased anchorage-independent growth. • We identified alterations in gene involved in cytoskeleton, cell adhesion.
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International Nuclear Information System (INIS)
Wu, Feng; Jordan, Ashley; Kluz, Thomas; Shen, Steven; Sun, Hong; Cartularo, Laura A.; Costa, Max
2016-01-01
The special AT-rich sequence-binding protein 2 (SATB2) is a protein that binds to the nuclear matrix attachment region of the cell and regulates gene expression by altering chromatin structure. In our previous study, we reported that SATB2 gene expression was induced in human bronchial epithelial BEAS-2B cells transformed by arsenic, chromium, nickel and vanadium. In this study, we show that ectopic expression of SATB2 in the normal human bronchial epithelial cell-line BEAS-2B increased anchorage-independent growth and cell migration, meanwhile, shRNA-mediated knockdown of SATB2 significantly decreased anchorage-independent growth in Ni transformed BEAS-2B cells. RNA sequencing analyses of SATB2 regulated genes revealed the enrichment of those involved in cytoskeleton, cell adhesion and cell-movement pathways. Our evidence supports the hypothesis that SATB2 plays an important role in BEAS-2B cell transformation. - Highlights: • We performed SATB2 overexpression in the BEAS-2B cell line. • We performed SATB2 knockdown in a Ni transformed BEAS-2B cell line. • SATB2 induced anchorage-independent growth and increased cell migration. • SATB2 knockdown significantly decreased anchorage-independent growth. • We identified alterations in gene involved in cytoskeleton, cell adhesion.
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Evolution of Mammalian Migrations for Refuge, Breeding, and Food
Gnanadesikan, Gitanjali E.; Pearse, William; Shaw, Allison K.
2017-01-01
Abstract Many organisms migrate between distinct habitats, exploiting variable resources while profoundly affecting ecosystem services, disease spread, and human welfare. However, the very characteristics that make migration captivating and significant also make it difficult to study, and we lack a comprehensive understanding of which species migrate and why. Here we show that, among mammals, migration is concentrated within Cetacea and Artiodactyla but also diffusely spread throughout the cl...
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Directory of Open Access Journals (Sweden)
Mi Ra Kim
2017-03-01
Full Text Available Vascular cell adhesion molecule-1 (VCAM-1 is closely associated with tumor progression and metastasis. However, the relevance and role of VCAM-1 in lung cancer have not been clearly elucidated. In this study, we found that VCAM-1 was highly overexpressed in lung cancer tissue compared with that of normal lung tissue, and high VCAM-1 expression correlated with poor survival in lung cancer patients. VCAM-1 knockdown reduced migration of A549 human lung cancer cells into Matrigel, and competitive blocking experiments targeting the Ig-like domain 6 of VCAM-1 (VCAM-1-D6 demonstrated that the VCAM-1-D6 domain was critical for VCAM-1 mediated A549 cell migration into Matrigel. Next, we developed a human monoclonal antibody specific to human and mouse VCAM-1-D6 (VCAM-1-D6 huMab, which was isolated from a human synthetic antibody library using phage display technology. Finally, we showed that VCAM-1-D6 huMab had a nanomolar affinity for VCAM-1-D6 and that it potently suppressed the migration of A549 and NCI-H1299 lung cancer cell lines into Matrigel. Taken together, these results suggest that VCAM-1-D6 is a key domain for regulating VCAM-1-mediated lung cancer invasion and that our newly developed VCAM-1-D6 huMab will be a useful tool for inhibiting VCAM-1-expressing lung cancer cell invasion.
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International Nuclear Information System (INIS)
Schwalm, Stephanie; Doell, Frauke; Roemer, Isolde; Bubnova, Svetlana; Pfeilschifter, Josef; Huwiler, Andrea
2008-01-01
Sphingosine kinases (SK) catalyze the production of sphingosine-1-phosphate which in turn regulates cell responses such as proliferation and migration. Here, we show that exposure of the human endothelial cell line EA.hy 926 to hypoxia stimulates a increased SK-1, but not SK-2, mRNA, protein expression, and activity. This effect was due to stimulated SK-1 promoter activity which contains two putative hypoxia-inducible factor-responsive-elements (HRE). By deletion of one of the two HREs, hypoxia-induced promoter activation was abrogated. Furthermore, hypoxia upregulated the expression of HIF-1α and HIF-2α, and both contributed to SK-1 gene transcription as shown by selective depletion of HIF-1α or HIF-2α by siRNA. The hypoxia-stimulated SK-1 upregulation was functionally coupled to increased migration since the selective depletion of SK-1, but not of SK-2, by siRNAs abolished the migratory response. In summary, these data show that hypoxia upregulates SK-1 activity and results in an accelerated migratory capacity of endothelial cells. SK-1 may thus serve as an attractive therapeutic target to treat diseases associated with increased endothelial migration and angiogenesis such as cancer growth and progression
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Interleukin-4 improves the migration of human myogenic precursor cells in vitro and in vivo
International Nuclear Information System (INIS)
Lafreniere, J.F.; Mills, P.; Bouchentouf, M.; Tremblay, J.P.
2006-01-01
Different molecules are available to recruit new neighboring myogenic cells to the site of regeneration. Formerly called B cell stimulatory factor-1, IL-4 can now be included in the list of motogenic factors. The present report demonstrates that human IL-4 is not required for fusion between mononucleated myoblasts but is required for myotube maturation. In identifying IL-4 as a pro-migratory agent for myogenic cells, these results provide a mechanism which partly explains IL-4 demonstrated activity during differentiation. Among the different mechanisms by which IL-4 might enhance myoblast migration processes, our results indicate that there are implications of some integrins and of three major components of the fibrinolytic system. Indeed, increases in the amount of active urokinase plasminogen activator and its receptor were observed following an IL-4 treatment, while the plasminogen activator inhibitor-1 decreased. Finally, IL-4 did not modify the amount of cell surface α5 integrin but increased the presence of β3 and β1 integrins. This integrin modulation might favor myogenic cell migration and its interaction with newly formed myotubes. Therefore, IL-4 co-injection with transplanted myoblasts might be an approach to enhance the migration of transplanted cells for the treatment of a damaged myocardium or of a Duchenne Muscular Dystrophy patient
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Landbird migration in the American West: Recent progress and future research directions
Carlisle, J.D.; Skagen, S.K.; Kus, B.E.; van Riper, Charles; Paxton, K.L.; Kelly, J.F.
2009-01-01
Our knowledge of avian behaviors during the nonbreeding period still lags behind that of the breeding season, but the last decade has witnessed a proliferation in research that has yielded significant progress in understanding migration patterns of North American birds. And, although historically the great majority of migration research has been conducted in the eastern half of the continent, there has been much recent progress on aspects of avian migration in the West. In particular, expanded use of techniques such as radar, plasma metabolites, mist-netting, count surveys, stable isotopes, genetic data, and animal tracking, coupled with an increase in multi-investigator collaborations, have all contributed to this growth of knowledge. There is increasing recognition that migration is likely the most limiting time of year for migratory birds, increasing the importance of continuing to decipher patterns of stopover ecology, identifying critical stopover habitats, and documenting migration routes in the diverse and changing landscapes of the American West. Here, we review and briefly synthesize the latest findings and advances in avian migration and consider research needs to guide future research on migration in the West. ?? 2009 by The Cooper Ornithological Society. All rights reserved.
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Time-lapse cinematography of the capillary tube cell migration inhibition test.
Bray, M A
1980-01-01
The kinetics of human and guinea pig cell migration inhibition have been studied using time-lapse cinematography of cells migrating from capillary tubes. Guinea pig and human cells exhibit markedly different kinetics in the absence of inhibitors. Specific antigen causes a dose-related inhibition of migration for up to 60 h using guinea pig cells and a peak of inhibition after 18 h using the human leucocyte system. The timing of measurement of maximum activity more critical for the latter test. The kinetics of lymphokine generation have been examined and the migration inhibitory activity of the plant mitogen (PHA), a Kurloff cell product and a continuous cell line supernatant have been compared with the inhibitory profiles of lymphokine preparations and specific antigen.
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SIRT-1 regulates TGF-β-induced dermal fibroblast migration via modulation of Cyr61 expression.
Kwon, Eun-Jeong; Park, Eun-Jung; Yu, Hyeran; Huh, Jung-Sik; Kim, Jinseok; Cho, Moonjae
2018-05-01
SIRT1 is a NAD-dependent protein deacetylase that participates in cellular regulation. The increased migration of fibroblasts is an important phenotype in fibroblast activation. The role of SIRT1 in cell migration remains controversial as to whether SIRT1 acts as an activator or suppressor of cell migration. Therefore, we have established the role of SIRT1 in the migration of human dermal fibroblasts and explored targets of SIRT1 during dermal fibroblast migration. SIRT1 and Cyr61 were expressed in human dermal fibroblasts and the stimulation with TGF-β further induced their expression. Treatment with resveratrol (RSV), a SIRT1 agonist, or overexpression of SIRT1 also promoted the expression Cyr61 in human dermal fibroblasts, whereas the inhibition of SIRT1 activity by nicotinamide or knockdown of SIRT1 decreased the level of Cyr61, as well as TGF-β or RSV-induced Cyr61 expression. Blocking of ERK signaling by PD98509 reduced the expression of Cyr61 induced by TGF-β or RSV. TGF-β, RSV, or SIRT1 overexpression enhanced β-catenin as well as Cyr61 expression. This stimulation was reduced by the Wnt inhibitor XAV939. RSV increased migration and nicotinamide attenuated RSV-induced migration of human dermal fibroblasts. Furthermore, SIRT1 overexpression promoted cell migration, whereas blocking Cyr61 attenuated SIRT1-stimulated migration of human dermal fibroblasts. SIRT1 increased cell migration by stimulating Cyr61 expression and the ERK and Wnt/β-catenin signaling. SIRT1-induced Cyr61 activity is very important for human dermal fibroblasts migration.
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Community Frames of Migration: The Path from Seaca to Spain
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Deliu Alexandra
2015-07-01
Full Text Available Transnational migration is a vast social phenomenon that has become a valid option for many Romanians since 1989. Romania is an emigration country and the favourite destinations of its citizens are Italy and Spain. This is the context in which I present my work, which focuses on the formation of transnational migration patterns from a village in the southern region of Romania. The data were generated during field research conducted in August 2012, and the empirical material consisted of field notes and interview transcripts corresponding to recorded conversations with local migrants, authority representatives and people without migration experience. In this particular community, two patterns of migration were identified, for which variables such as ethnicity (Roma/Romanian and religious orientation (Orthodoxy/Adventism appear to have explanatory power. My inquiry takes as its starting point the identification of this variety of migration patterns and concentrates on analysing them in the regional and national contexts based on the scholarly framework provided by network theory. Two major differences exist between them: the time frame of living and working abroad (clearly demarcated as three months, six months or indefinite and the nature of the work environment (departures based on a work contract between the migrant and a company located at the destination and departures accompanied by uncertainty regarding workplace concerns upon arrival. Making sense of these life strategies and their local configurations are the objectives of this paper.
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Substrate Curvature Regulates Cell Migration -A Computational Study
He, Xiuxiu; Jiang, Yi
Cell migration in host microenvironment is essential to cancer etiology, progression and metastasis. Cellular processes of adhesion, cytoskeletal polymerization, contraction, and matrix remodeling act in concert to regulate cell migration, while local extracellular matrix architecture modulate these processes. In this work we study how stromal microenvironment with native and cell-derived curvature at micron-meter scale regulate cell motility pattern. We developed a 3D model of single cell migration on a curved substrate. Mathematical analysis of cell morphological adaption to the cell-substrate interface shows that cell migration on convex surfaces deforms more than on concave surfaces. Both analytical and simulation results show that curved surfaces regulate the cell motile force for cell's protruding front through force balance with focal adhesion and cell contraction. We also found that cell migration on concave substrates is more persistent. These results offer a novel biomechanical explanation to substrate curvature regulation of cell migration. NIH 1U01CA143069.
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Patterns of differences in brain morphology in humans as compared to extant apes.
Aldridge, Kristina
2011-01-01
Although human evolution is characterized by a vast increase in brain size, it is not clear whether or not certain regions of the brain are enlarged disproportionately in humans, or how this enlargement relates to differences in overall neural morphology. The aim of this study is to determine whether or not there are specific suites of features that distinguish the morphology of the human brain from that of apes. The study sample consists of whole brain, in vivo magnetic resonance images (MRIs) of anatomically modern humans (Homo sapiens sapiens) and five ape species (gibbons, orangutans, gorillas, chimpanzees, bonobos). Twenty-nine 3D landmarks, including surface and internal features of the brain were located on 3D MRI reconstructions of each individual using MEASURE software. Landmark coordinate data were scaled for differences in size and analyzed using Euclidean Distance Matrix Analysis (EDMA) to statistically compare the brains of each non-human ape species to the human sample. Results of analyses show both a pattern of brain morphology that is consistently different between all apes and humans, as well as patterns that differ among species. Further, both the consistent and species-specific patterns include cortical and subcortical features. The pattern that remains consistent across species indicates a morphological reorganization of 1) relationships between cortical and subcortical frontal structures, 2) expansion of the temporal lobe and location of the amygdala, and 3) expansion of the anterior parietal region. Additionally, results demonstrate that, although there is a pattern of morphology that uniquely defines the human brain, there are also patterns that uniquely differentiate human morphology from the morphology of each non-human ape species, indicating that reorganization of neural morphology occurred at the evolutionary divergence of each of these groups. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Lee, Hye Shin; Cheerathodi, Mujeeburahiman; Chaki, Sankar P.; Reyes, Steve B.; Zheng, Yanhua; Lu, Zhimin; Paidassi, Helena; DerMardirossian, Celine; Lacy-Hulbert, Adam; Rivera, Gonzalo M.
2015-01-01
Directional cell motility is essential for normal development and physiology, although how motile cells spatiotemporally activate signaling events remains largely unknown. Here, we have characterized an adhesion and signaling unit comprised of protein tyrosine phosphatase (PTP)-PEST and the extracellular matrix (ECM) adhesion receptor β8 integrin that plays essential roles in directional cell motility. β8 integrin and PTP-PEST form protein complexes at the leading edge of migrating cells and balance patterns of Rac1 and Cdc42 signaling by controlling the subcellular localization and phosphorylation status of Rho GDP dissociation inhibitor 1 (RhoGDI1). Translocation of Src-phosphorylated RhoGDI1 to the cell's leading edge promotes local activation of Rac1 and Cdc42, whereas dephosphorylation of RhoGDI1 by integrin-bound PTP-PEST promotes RhoGDI1 release from the membrane and sequestration of inactive Rac1/Cdc42 in the cytoplasm. Collectively, these data reveal a finely tuned regulatory mechanism for controlling signaling events at the leading edge of directionally migrating cells. PMID:25666508
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Globalization of international migration: Social challenges and policy implication
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I A Aleshkovski
2017-12-01
Full Text Available In the second half of the XX century, the humankind witnessed the insurmountable and irreversible power of globalization processes, which influence all spheres of social life and establish a global system of interdependency between countries and nations. Globalization within impetuous changes in global political, social and economic systems has determined dramatic shifts in the international migration processes that lead to the new stage of migration history. In nowadays globalized world, international migration has become a reality for almost all corners of the globe. The author considers features of the recent trends of international migration: the unprecedented growth of the international migration flows; the widening geography of international migration that involves nearly all countries of the world; qualitative changes in the structure of international migration flows; the key role of economic migration; the permanent growth and structural intricateness of irregular migration; the increasing scale and geographical widening of forced migration; the growing importance of international migration for the demographic development of the world, countries of both origin and destination. All these trends combined prove that the international migration patterns have become more complex. The author analyzes the legal framework of the international migration processes, and gives recommendations on the ways to improve the control and regulation of migration processes. Specific issues related to the social challenges of international migration are also discussed in the article.
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Ali, Mehboob; Heyob, Kathryn; Rogers, Lynette K.
2016-01-01
AIMS Deaths associated with cancer metastasis have steadily increased making the need for newer, anti-metastatic therapeutics imparative. Gelsolin and vimentin, actin binding proteins expressed in metastatic tumors, participate in actin remodelling and regulate cell migration. Docosahexaenoic acid (DHA) limits cancer cell proliferation and adhesion but the mechanisms involved in reducing metastatic phenotypes are unknown. We aimed to investigate the effects of DHA on gelsolin and vimentin expression, and ultimately cell migration and proliferation, in this context. MAIN METHODS Non-invasive lung epithelial cells (MLE12) and invasive lung cancer cells (A549) were treated with DHA (30 μmol/ml) or/and 8 bromo-cyclic adenosine monophosphate (8 Br-cAMP) (300 μmol/ml) for 6 or 24 h either before (pre-treatment) or after (post-treatment) plating in transwells. Migration was assessed by the number of cells that progressed through the transwell. Gelsolin and vimentin expression were measured by western blot and confocal microscopy in cells, and by immunohistochemistry in human lung cancer biospy samples. KEY FINDINGS A significant decrease in cell migration was detected for A549 cells treated with DHA verses control but this same decrease was not seen in MLE12 cells. DHA and 8 Br-cAMP altered gelsolin and vimentin expression but no clear pattern of change was observed. Immunoflorescence staining indicated slightly higher vimentin expression in human lung tissue that was malignant compared to control. SIGNIFICANCE Collectively, our data indicate that DHA inhibits cancer cell migration and further suggests that vimentin and gelsolin may play secondary roles in cancer cell migration and proliferation, but are not the primary regulators. PMID:27157519
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International Nuclear Information System (INIS)
Samandari, Elika; Visarius, Theresa; Zingg, Jean-Marc; Azzi, Angelo
2006-01-01
The effect of vitamin E on proliferation, integrin expression, adhesion, and migration in human glioma cells has been studied. γ-tocopherol at 50 μM concentration exerted more inhibitory effect than α-tocopherol at the same concentration on glioma cell proliferation. Integrin α5 and β1 protein levels were increased upon both α- and γ-tocopherol treatments. In parallel, an increase in the α5β1 heterodimer cell surface expression was observed. The tocopherols inhibited glioma cell-binding to fibronectin where γ-tocopherol treatment induced glioma cell migration. Taken together, the data reported here are consistent with the notion that the inhibition of glioma cell proliferation induced by tocopherols may be mediated, at least in part, by an increase in integrin α5 and β1 expression. Cell adhesion is also negatively affected by tocopherols, despite a small increase in the surface appearance of the α5β1 heterodimer. Cell migration is stimulated by γ-tocopherol. It is concluded that α5 and β1 integrin expression and surface appearance are not sufficient to explain all the observations and that other integrins or in general other factors may be associated with these events
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The research status and prospect of tritium migration in soil-plant system
International Nuclear Information System (INIS)
Qiu Guohua
2011-01-01
In this paper, the research significance and progress of tritium migration in soil-plant system are briefly introduced, which includes spatial and temporal distribution, migration pattern and influence factors, chemical forms, mathematical models of tritium migration in different soil and plant. The research results are summarized, and the existing problems in research process are analyzed and discussed. (authors)
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Directory of Open Access Journals (Sweden)
Inna Maltseva
Full Text Available Corneal epithelial wound repair involves the migration of epithelial cells to cover the defect followed by the proliferation of the cells to restore thickness. Heparan sulfate proteoglycans (HSPGs are ubiquitous extracellular molecules that bind to a plethora of growth factors, cytokines, and morphogens and thereby regulate their signaling functions. Ligand binding by HS chains depends on the pattern of four sulfation modifications, one of which is 6-O-sulfation of glucosamine (6OS. SULF1 and SULF2 are highly homologous, extracellular endosulfatases, which post-synthetically edit the sulfation status of HS by removing 6OS from intact chains. The SULFs thereby modulate multiple signaling pathways including the augmentation of Wnt/ß-catenin signaling. We found that wounding of mouse corneal epithelium stimulated SULF1 expression in superficial epithelial cells proximal to the wound edge. Sulf1⁻/⁻, but not Sulf2⁻/⁻, mice, exhibited a marked delay in healing. Furthermore, corneal epithelial cells derived from Sulf1⁻/⁻ mice exhibited a reduced rate of migration in repair of a scratched monolayer compared to wild-type cells. In contrast, human primary corneal epithelial cells expressed SULF2, as did a human corneal epithelial cell line (THCE. Knockdown of SULF2 in THCE cells also slowed migration, which was restored by overexpression of either mouse SULF2 or human SULF1. The interchangeability of the two SULFs establishes their capacity for functional redundancy. Knockdown of SULF2 decreased Wnt/ß-catenin signaling in THCE cells. Extracellular antagonists of Wnt signaling reduced migration of THCE cells. However in SULF2- knockdown cells, these antagonists exerted no further effects on migration, consistent with the SULF functioning as an upstream regulator of Wnt signaling. Further understanding of the mechanistic action of the SULFs in promoting corneal repair may lead to new therapeutic approaches for the treatment of corneal injuries.
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The evolution of immunity in relation to colonization and migration.
O'Connor, Emily A; Cornwallis, Charlie K; Hasselquist, Dennis; Nilsson, Jan-Åke; Westerdahl, Helena
2018-05-01
Colonization and migration have a crucial effect on patterns of biodiversity, with disease predicted to play an important role in these processes. However, evidence of the effect of pathogens on broad patterns of colonization and migration is limited. Here, using phylogenetic analyses of 1,311 species of Afro-Palaearctic songbirds, we show that colonization events from regions of high (sub-Saharan Africa) to low (the Palaearctic) pathogen diversity were up to 20 times more frequent than the reverse, and that migration has evolved 3 times more frequently from African- as opposed to Palaearctic-resident species. We also found that resident species that colonized the Palaearctic from Africa, as well as African species that evolved long-distance migration to breed in the Palaearctic, have reduced diversity of key immune genes associated with pathogen recognition (major histocompatibility complex class I). These results suggest that changes in the pathogen community that occur during colonization and migration shape the evolution of the immune system, potentially by adjusting the trade-off between the benefits of extensive pathogen recognition and the costs of immunopathology that result from high major histocompatibility complex class I diversity.
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Directory of Open Access Journals (Sweden)
Johannes Tsheola
2015-12-01
Full Text Available This article seeks to examine the association of the concept of governance of international relations and, by implication, human population migration, through the rigid practices of “sovereignty-state-territory triad” with the fomentation and exacerbation of societal stereotypes, attitudes and perceptions of xenophobia in Africa, in general, and South Africa, in particular. Ascriptions of the majority of population migration as “international” affirms the centrality of the operationalisation of the “sovereignty-state-territory triad” in understanding the fragmentary constructions of societal attitudes and perceptions of people resident in distinct geopolitical entities ascribed as national territories. State and non-state governance entrapments with this triad perpetuate societal stereotypes that are in concurrence with bordered-territories where populations described as citizens are stimulated to protect endowments and resources of the land against the perceived destruction associated with the conduct of the out-groups. Unsurprisingly, the theorisation of human population migration has equally been intricately involved with environmental conservation and securitisation of biodiversity that enables land dispossession of the vulnerable sections of the population through the Western economic narratives of “Peace Parks”. Simultaneously in Southern Africa, the concept of African Renaissance, inescapably embedded with “cooperation and conflict” at all scales, has offered a buzzword to be realised through “Peace Parks” that have evidently failed to deliver reaffirmation of African cultures, continental emancipation and democratisation. The preeminence of societal stereotypes, attitudes and perceptions of xenophobia and violent abuses of African immigrants in South Africa provides vivid illustrations of the inconsistencies and non-linearity of concepts such as African Renaissance and “Peace Parks”. This article asserts that
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The health impacts of climate-related migration.
Schwerdtle, Patricia; Bowen, Kathryn; McMichael, Celia
2017-12-11
Changes in climate, in conjunction with other drivers of mobility, shape human migration. While there is an increasing focus on the adaptive potential of migration, the health impacts of climate-related migration, including planned relocation and forced displacement, have not been thoroughly examined. The Intergovernmental Panel on Climate Change stated that migration is currently, and will increasingly be, influenced by environmental degradation and climate change, and that it needs to be addressed in a focused and coordinated manner. This paper examines the links between climate change, migration, and health, considering diverse migration responses, including immobility, forced displacement and planned migration, as well as the associated health risks and opportunities in different contexts. Using case studies, the paper illustrates strategies to reduce the health risks associated with climate change-related migration. While there is an increasing body of research examining the climate change-migration nexus, a dual approach is now required. This approach must include debate and further research regarding the health consequences and responses associated with climate migration as well as immediate strengthening of health systems to make them both climate resilient and migrant inclusive.
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MIGRATION AND REGIONAL DEVELOPMENT IN ROMANIA
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CAMELIA ANGHEL
2017-12-01
Full Text Available Economic implications of demographic decline and the changing age structure will be more visible in Romania after 2020, when the working population will decrease gradually and "mature" groups will come in the elderly population. Diminishing populations will cause a change in the economic dependency ratio and total economic burden of the working population will increase. The changes known in activity rates in the future are hard to predict, especially in the current context of labor migration in Europe. In this context, a realistic vision of economic and social development in the coming decades is a necessity for Romania. Where the countries of origin of migrants fail to implement clear and efficient social and economic general reforms, migration and remittances get involved whose fundamental purpose is although they do not contribute to the sustainable development at the national level. Population migration has now become a global issue important to the development and welfare societies. Remittances are the main concern in studies of migration and development, migration transnational model several years as part of concerns about the economic future of many countries. Focus as well can be seen throughout this paper falls on cash remittances and consumer goods, on issues related to sustainable development, social development, human development. Many experts consider impossible the debate on economic development without taking into account human and social development, even sustainable development.
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Determinants of the Egyptian labour migration.
Kandil, M; Metwally, M
1992-03-01
The objective is to summarize the pattern of Egyptian migration to Arab oil-producing countries (AOPC), to review some factors that are important determinants of labor movement based on theory, and to empirically model the migration rate to AOPC and to Saudi Arabia. Factors are differentiated as to their relative importance. Push factors are the low wages, high inflation rate, and high population density in Egypt; pull factors are higher wages. It is predicted that an increase in income from destination countries has a significant positive impact on the migration rate. An increase in population density stimulates migration. An increase in inflation acts to increase out-migration with a 2-year lag, which accommodates departure preparation. Egypt's experience with labor migration is described for the pre-oil boom, and the post-oil boom. Several estimates of labor migration are given. Government policy toward migration is positive. Theory postulates migration to be determined by differences in the availability of labor, labor rewards between destination and origin, and the cost of migration. In the empirical model, push factors are population density, the current inflation rate, and the ratio of income/capita in AOPC to Egypt. The results indicate that the ratio of income/capita had a strong pull impact and population density had a strong push impact. The inflation rate has a positive impact with a lag estimated at 2 years. Prior to the Camp David Accord, there was a significant decrease in the number of Egyptian migrants due to political tension. The findings support the classical theory of factor mobility. The consequences of migration on the Egyptian economy have been adverse. Future models should disaggregate data because chronic shortages exist in some parts of the labor market. Manpower needs assessment would be helpful for policy makers.
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Understanding oceanic migrations with intrinsic biogeochemical markers.
Directory of Open Access Journals (Sweden)
Raül Ramos
2009-07-01
Full Text Available Migratory marine vertebrates move annually across remote oceanic water masses crossing international borders. Many anthropogenic threats such as overfishing, bycatch, pollution or global warming put millions of marine migrants at risk especially during their long-distance movements. Therefore, precise knowledge about these migratory movements to understand where and when these animals are more exposed to human impacts is vital for addressing marine conservation issues. Because electronic tracking devices suffer from several constraints, mainly logistical and financial, there is emerging interest in finding appropriate intrinsic markers, such as the chemical composition of inert tissues, to study long-distance migrations and identify wintering sites. Here, using tracked pelagic seabirds and some of their own feathers which were known to be grown at different places and times within the annual cycle, we proved the value of biogeochemical analyses of inert tissue as tracers of marine movements and habitat use. Analyses of feathers grown in summer showed that both stable isotope signatures and element concentrations can signal the origin of breeding birds feeding in distinct water masses. However, only stable isotopes signalled water masses used during winter because elements mainly accumulated during the long breeding period are incorporated into feathers grown in both summer and winter. Our findings shed new light on the simple and effective assignment of marine organisms to distinct oceanic areas, providing new opportunities to study unknown migration patterns of secretive species, including in relation to human-induced mortality on specific populations in the marine environment.
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Transnational nurse migration: future directions for medical anthropological research.
Prescott, Megan; Nichter, Mark
2014-04-01
Transnational nurse migration is a serious global health issue in which inequitably distributed shortages hinder health and development goals. This article selectively reviews the literature on nurse migration that has emerged from nursing, health planning, and the social sciences and offers productive directions for future anthropological research. The literature on global nurse migration has largely focused on push/pull economic logic and the concept of brain drain to understand the causes and effects of nurse migration. These concepts obscure political-economic, historical, and cultural factors that pattern nurse migration and influence the complex effects of nurse migration. Global nurse care chain analysis helps illuminate the numerous nodes in the production and migration of nurses, and management of this transnational process. Examples are provided from the Philippines and India to illustrate ways in which this analysis may be deepened, refined and rendered more critical by anthropological research. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Guzman, Efrain; Taylor, Geraldine; Hope, Jayne; Herbert, Rebecca; Cubillos-Zapata, Carolina; Charleston, Bryan
2016-10-01
Dendritic cells (DC) are central to the initiation of immune responses, and various approaches have been used to target vaccines to DC in order to improve immunogenicity. Cannulation of lymphatic vessels allows for the collection of DC that migrate from the skin. These migrating DC are involved in antigen uptake and presentation following vaccination. Human replication-deficient adenovirus (AdV) 5 is a promising vaccine vector for delivery of recombinant antigens. Although the mechanism of AdV attachment and penetration has been extensively studied in permissive cell lines, few studies have addressed the interaction of AdV with DC. In this study, we investigated the interaction of bovine skin-migrating DC and replication-deficient AdV-based vaccine vectors. We found that, despite lack of expression of Coxsackie B-Adenovirus Receptor and other known adenovirus receptors, AdV readily enters skin-draining DC via an actin-dependent endocytosis. Virus exit from endosomes was pH independent, and neutralizing antibodies did not prevent virus entry but did prevent virus translocation to the nucleus. We also show that combining adenovirus with adjuvant increases the absolute number of intracellular virus particles per DC but not the number of DC containing intracellular virus. This results in increased trans-gene expression and antigen presentation. We propose that, in the absence of Coxsackie B-Adenovirus Receptor and other known receptors, AdV5-based vectors enter skin-migrating DC using actin-dependent endocytosis which occurs in skin-migrating DC, and its relevance to vaccination strategies and vaccine vector targeting is discussed.
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Using Virtual ATE Model to Migrate Test Programs
Institute of Scientific and Technical Information of China (English)
王晓明; 杨乔林
1995-01-01
Bacause of high development costs of IC (Integrated Circuit)test programs,recycling existing test programs from one kind of ATE (Automatic Test Equipment) to another or generating directly from CAD simulation modules to ATE is more and more valuable.In this paper,a new approach to migrating test programs is presented.A virtual ATE model based on object-oriented paradigm is developed;it runs Test C++ (an intermediate test control language) programs and TeIF(Test Inftermediate Format-an intermediate pattern),migrates test programs among three kinds of ATE (Ando DIC8032,Schlumberger S15 and GenRad 1732) and generates test patterns from two kinds of CAD 9Daisy and Panda) automatically.
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Economic, social and gender aspects of the international migration in Moldova
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Dorin VACULOVSCHI
2016-06-01
Full Text Available International labor migration is one of the most marked phenomenon that characterize the current situation on the Moldovan labor market. Geographical and gender distribution in labor migration is largely determined by the type of work that provide migrant workers. Women migrate to provide domestic and care services abroad, delegating in the same time their responsibilities in this area to other people, leads to the constitution of so-called global care chains. Migration with the purpose of study in Moldova is accompanied by a negative phenomenon, of the departure of highly qualified specialists. International migration of highly skilled labor, known as "brain drain"clearly evokes a loss of intellectual capital. Moldova continues to be characterized as an origin country of human beings trafficking, being at lesser extent a country of transit of human trafficking victims from NIS countries to Europe. The lack of some measures from the Government on “human capital loss” problem will essentially reduce the chances of exit from the crisis.
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Migration: Pre-Requisite for Rural Economic Regeneration?
Stockdale, Aileen
2006-01-01
Migration from and to depopulating areas is related to the prospects for rural economic regeneration. The focus is on whether or not migration processes give rise to the necessary human capital required for successful endogenous development. Data from Scottish case studies pertaining to in-, out- and return migrants are analysed. Only by leaving…
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Suppression of Human Liver Cancer Cell Migration and Invasion via the GABAA Receptor
International Nuclear Information System (INIS)
Chen, Zhi-ao; Bao, Mei-yan; Xu, Yong-fen; Zha, Ruo-peng; Shi, Hai-bing; Chen, Tao-yang; He, Xiang-huo
2012-01-01
To investigate the roles of the γ-aminobutyric acid (GABA) in the metastasis of hepatocellular carcinoma (HCC) and to explore the potential of a novel therapeutic approach for the treatment of HCC. The expression levels of GABA receptor subunit genes in various HCC cell lines and patients‘ tissues were detected by quantitative real-time polymerase chain reaction and Western blot analysis. Transwell cell migration and invasion assays were carried out for functional analysis. The effects of GABA on liver cancer cell cytoskeletal were determined by immunofluorescence staining. And the effects of GABA on HCC metastasis in nude mice were evaluated using an in vivo orthotopic model of liver cancer. The mRNA level of GABA receptor subunits varied between the primary hepatocellular carcinoma tissue and the adjacent non-tumor liver tissue. GABA inhibited human liver cancer cell migration and invasion via the ionotropic GABA A receptor as a result of the induction of liver cancer cell cytoskeletal reorganization. Pretreatment with GABA also significantly reduced intrahepatic liver metastasis and primary tumor formation in vivo. These findings introduce a potential and novel therapeutic approach for the treatment of cancer patients based on the modulation of the GABAergic system
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Gaurav, Rohit; Bewtra, Againdra K; Agrawal, Devendra K
2015-08-01
Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is responsible for respiratory burst in immune cells. Chloride channel 3 (CLC3) has been linked to the respiratory burst in eosinophils and neutrophils. The effect of cytokines and the involvement of CLC3 in the regulation of NADPH-dependent oxidative stress and on cytokine-mediated migration of eosinophils are not known. Human peripheral blood eosinophils were isolated from healthy individuals and from individuals with asthma by negative selection. Real-time PCR was used to detect the expression of NADPH oxidases in eosinophils. Intracellular reactive oxygen species (ROS) measurement was done with flow cytometry. Superoxide generation was measured with transforming growth factor (TGF)-β, eotaxin, and CLC3 blockers. CLC3 dependence of eosinophils in TGF-β- and eotaxin-induced migration was also examined. The messenger RNA (mRNA) transcripts of NADPH oxidase (NOX) 2, dual oxidase (DUOX) 1, and DUOX2 were detected in blood eosinophils, with very low expression of NOX1, NOX3, and NOX5 and no NOX4 mRNA. The level of NOX2 mRNA transcripts increased with disease severity in the eosinophils of subjects with asthma compared with healthy nonatopic volunteers. Change in granularity and size in eosinophils, but no change in intracellular ROS, was observed with phorbol myristate acetate (PMA). PMA, TGF-β, and eotaxin used the CLC3-dependent pathway to increase superoxide radicals. TGF-β and eotaxin induced CLC3-dependent chemotaxis of eosinophils. These findings support the requirement of CLC3 in the activation and migration of human blood eosinophils and may provide a potential novel therapeutic target to regulate eosinophil hyperactivity in allergic airway inflammation in asthma.
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Mexican experience on migration and development 1990-2013
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Rodolfo García Zamora
Full Text Available After 40 years of a long rising emigration from Mexico to the United States, the number of Mexicans increased to 12 million in 2006, while the increased input of remittances reached $26 million dollars in 2007. Yet, the increasing migration and remittances mainly in Zacatecas and Michoacan states do not achieve economic and social development because of the persistent backwardness, unemployment and marginalization. It demands the need for new Policies of Development, Migration and Human Rights that allow exercising the right to not emigrate in a medium term. Positive products of this long migration are the Mexican Migrant Clubs and their Federations that elaborated the concrete development proposals. Whereas, the possibility that these proposals can become a Development, Migration and Human Rights, Comprehensive and Long Term State Policy will depend on the capacity and participation of Mexican Civil Society and the Transnational Communities in both countries.
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Impact of cell adhesion and migration on nanoparticle uptake and cellular toxicity.
Pitchaimani, Arunkumar; Nguyen, Tuyen Duong Thanh; Koirala, Mukund; Zhang, Yuntao; Aryal, Santosh
2017-09-01
In vitro cell-nanoparticle (NP) studies involve exposure of NPs onto the monolayer cells growing at the bottom of a culture plate, and assumed that the NPs evenly distributed for a dose-responsive effect. However, only a few proportion of the administered dose reaches the cells depending on their size, shape, surface, and density. Often the amount incubated (administered dose) is misled as a responsive dose. Herein, we proposed a cell adhesion-migration (CAM) strategy, where cells incubated with the NP coated cell culture substrate to maximize the cell-NP interaction and investigated the physiological properties of the cells. In the present study, cell adhesion and migration pattern of human breast cancer cell (MCF-7) and mouse melanoma cell (B16-F10) on cell culture substrate decorated with toxic (cetyltrimethylammonium bromide, CTAB) and biocompatible (poly (sodium 4-styrenesulphonate), PSS) gold nanoparticles (AuNPs) of different sizes (5 and 40nm) were investigated and evaluated for cellular uptake efficiency, proliferation, and toxicity. Results showed enhanced cell adhesion, migration, and nanoparticle uptake only on biocompatible PSS coated AuNP, irrespective of its size. Whereas, cytotoxic NP shows retard proliferation with reduced cellular uptake efficiency. Considering the importance of cell adhesion and migration on cellular uptake and cytotoxicity assessment of nanoparticle, CAM strategy would hold great promises in cell-NP interaction studies. Copyright © 2017. Published by Elsevier Ltd.
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Similar Fracture Patterns in Human Nose and Gothic Cathedral.
Lee, Shu Jin; Tse, Kwong Ming; Lee, Heow Pueh
2015-10-01
This study proposes that the bony anatomy of the human nose and masonry structure of the Gothic cathedral are geometrically similar, and have common fracture patterns. We also aim to correlate the fracture patterns observed in patients' midface structures with those seen in the Gothic cathedral using computational approach. CT scans of 33 patients with facial fractures were examined and compared with computer simulations of both the Gothic cathedral and human nose. Three similar patterns were found: (1) Cracks of the nasal arch with crumpling of the vertical buttresses akin to the damage seen during minor earthquakes; (2) lateral deviation of the central nasal arch and collapse of the vertical buttresses akin to those due to lateral forces from wind and in major earthquakes; and (3) Central arch collapse seen as a result of collapse under excessive dead weight. Interestingly, the finding of occult nasal and septal fractures in the mandible fractures with absence of direct nasal trauma highlights the possibility of transmission of forces from the foundation to the arch leading to structural failure. It was also found that the structural buttresses of the Gothic cathedral delineate the vertical buttresses in the human midface structure. These morphologic similarities between the human nose and Gothic cathedral will serve as a basis to study the biomechanics of nasal fractures. Identification of structural buttresses in a skeletal structure has important implications for reconstruction as reestablishment of structural continuity restores normal anatomy and architectural stability of the human midface structure. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
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A THREE-STEP SPATIAL-TEMPORAL-SEMANTIC CLUSTERING METHOD FOR HUMAN ACTIVITY PATTERN ANALYSIS
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W. Huang
2016-06-01
Full Text Available How people move in cities and what they do in various locations at different times form human activity patterns. Human activity pattern plays a key role in in urban planning, traffic forecasting, public health and safety, emergency response, friend recommendation, and so on. Therefore, scholars from different fields, such as social science, geography, transportation, physics and computer science, have made great efforts in modelling and analysing human activity patterns or human mobility patterns. One of the essential tasks in such studies is to find the locations or places where individuals stay to perform some kind of activities before further activity pattern analysis. In the era of Big Data, the emerging of social media along with wearable devices enables human activity data to be collected more easily and efficiently. Furthermore, the dimension of the accessible human activity data has been extended from two to three (space or space-time to four dimensions (space, time and semantics. More specifically, not only a location and time that people stay and spend are collected, but also what people “say” for in a location at a time can be obtained. The characteristics of these datasets shed new light on the analysis of human mobility, where some of new methodologies should be accordingly developed to handle them. Traditional methods such as neural networks, statistics and clustering have been applied to study human activity patterns using geosocial media data. Among them, clustering methods have been widely used to analyse spatiotemporal patterns. However, to our best knowledge, few of clustering algorithms are specifically developed for handling the datasets that contain spatial, temporal and semantic aspects all together. In this work, we propose a three-step human activity clustering method based on space, time and semantics to fill this gap. One-year Twitter data, posted in Toronto, Canada, is used to test the clustering-based method. The
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Globalization of leptospirosis through travel and migration.
Bandara, Medhani; Ananda, Mahesha; Wickramage, Kolitha; Berger, Elisabeth; Agampodi, Suneth
2014-08-12
Leptospirosis remains the most widespread zoonotic disease in the world, commonly found in tropical or temperate climates. While previous studies have offered insight into intra-national and intra-regional transmission, few have analyzed transmission across international borders. Our review aimed at examining the impact of human travel and migration on the re-emergence of Leptospirosis. Results suggest that alongside regional environmental and occupational exposure, international travel now constitute a major independent risk factor for disease acquisition. Contribution of travel associated leptospirosis to total caseload is as high as 41.7% in some countries. In countries where longitudinal data is available, a clear increase of proportion of travel-associated leptospirosis over the time is noted. Reporting patterns is clearly showing a gross underestimation of this disease due to lack of diagnostic facilities. The rise in global travel and eco-tourism has led to dramatic changes in the epidemiology of Leptospirosis. We explore the obstacles to prevention, screening and diagnosis of Leptopirosis in health systems of endemic countries and of the returning migrant or traveler. We highlight the need for developing guidelines and preventive strategies of Leptospirosis related to travel and migration, including enhancing awareness of the disease among health professionals in high-income countries.
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Directory of Open Access Journals (Sweden)
Shuangxi Li
2017-12-01
Full Text Available Background/Aims: Calycosin, a phytoestrogenic compound, has recently emerged as a promising antitumor drug. It has been shown that calycosin suppresses growth and induces apoptosis of breast cancer cells. However, the effect of calycosin on migration and invasion of breast cancer cells and the underlying molecular mechanisms have not been elucidated. Methods: Human breast cancer cells MCF-7 and T47D were treated with, or without, different doses (0, 6.25, 12.5, 25, 50, 100 or 150 μM of calycosin, and the viability of different groups was determined by MTT assay. Next, the inhibitory effect of higher doses (50, 100 or 150 μM of calycosin on migration and invasion of the two cell lines was determined by wound healing and transwell assay. The relative expression levels of forkhead box P3 (Foxp3, vascular endothelial growth factor (VEGF and matrix metalloproteinase-9 (MMP-9 in MCF-7 and T47D cells were determined by quantitative RT-PCR and Western blot. Results: Treatment with lower doses (6.25 or 12.5 μM promoted proliferation of breast cancer cells, but with higher doses significantly reduced the viability of MCF-7 and T47D cells. Furthermore, higher doses of calycosin were found to inhibit migration and invasion of the two cell lines in a dose-dependent manner. Additionally, treatment with a higher dose of calycosin significantly reduced the expression levels of Foxp3, followed by down-regulation of VEGF and MMP-9 in both MCF-7 and T47D breast cancer cells. Conclusion: Treatment with a higher dose of calycosin tends to reduce migration and invasion capacity of human breast cancer cells, by targeting Foxp3-mediated VEGF and MMP-9 expression.
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Eom, Tae-Yeon; Stanco, Amelia; Guo, Jiami; Wilkins, Gary; Deslauriers, Danielle; Yan, Jessica; Monckton, Chase; Blair, Josh; Oon, Eesim; Perez, Abby; Salas, Eduardo; Oh, Adrianna; Ghukasyan, Vladimir; Snider, William D.; Rubenstein, John L. R.; Anton, E. S.
2014-01-01
Coordinated migration of distinct classes of neurons to appropriate positions leads to the formation of functional neuronal circuitry in the cerebral cortex. Two major classes of cortical neurons, interneurons and projection neurons, utilize distinctly different modes (radial vs. tangential) and routes of migration to arrive at their final positions in the cerebral cortex. Here, we show that adenomatous polyposis coli (APC) modulates microtubule (MT) severing in interneurons to facilitate tangential mode of interneuron migration, but not the glial-guided, radial migration of projection neurons. APC regulates the stability and activity of the MT severing protein p60-katanin in interneurons to promote the rapid remodeling of neuronal processes necessary for interneuron migration. These findings reveal how severing and restructuring of MTs facilitate distinct modes of neuronal migration necessary for laminar organization of neurons in the developing cerebral cortex. PMID:25535916
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Automation of Flexible Migration Workflows
Directory of Open Access Journals (Sweden)
Dirk von Suchodoletz
2011-03-01
Full Text Available Many digital preservation scenarios are based on the migration strategy, which itself is heavily tool-dependent. For popular, well-defined and often open file formats – e.g., digital images, such as PNG, GIF, JPEG – a wide range of tools exist. Migration workflows become more difficult with proprietary formats, as used by the several text processing applications becoming available in the last two decades. If a certain file format can not be rendered with actual software, emulation of the original environment remains a valid option. For instance, with the original Lotus AmiPro or Word Perfect, it is not a problem to save an object of this type in ASCII text or Rich Text Format. In specific environments, it is even possible to send the file to a virtual printer, thereby producing a PDF as a migration output. Such manual migration tasks typically involve human interaction, which may be feasible for a small number of objects, but not for larger batches of files.We propose a novel approach using a software-operated VNC abstraction layer in order to replace humans with machine interaction. Emulators or virtualization tools equipped with a VNC interface are very well suited for this approach. But screen, keyboard and mouse interaction is just part of the setup. Furthermore, digital objects need to be transferred into the original environment in order to be extracted after processing. Nevertheless, the complexity of the new generation of migration services is quickly rising; a preservation workflow is now comprised not only of the migration tool itself, but of a complete software and virtual hardware stack with recorded workflows linked to every supported migration scenario. Thus the requirements of OAIS management must include proper software archiving, emulator selection, system image and recording handling. The concept of view-paths could help either to automatically determine the proper pre-configured virtual environment or to set up system
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Kim, W.; Kim, Y.; Min, D.; Oh, J.; Huh, C.; Kang, S.
2012-12-01
During last two decades, CO2 sequestration in the subsurface has been extensively studied and progressed as a direct tool to reduce CO2 emission. Commercial projects such as Sleipner, In Salah and Weyburn that inject more than one million tons of CO2 per year are operated actively as well as test projects such as Ketzin to study the behavior of CO2 and the monitoring techniques. Korea also began the CCS (CO2 capture and storage) project. One of the prospects for CO2 sequestration in Korea is the southwestern continental margin of Ulleung basin. To monitor the behavior of CO2 underground for the evaluation of stability and safety, several geophysical monitoring techniques should be applied. Among various geophysical monitoring techniques, seismic survey is considered as the most effective tool. To verify CO2 migration in the subsurface more effectively, seismic numerical simulation is an essential process. Furthermore, the efficiency of the seismic migration techniques should be investigated for various cases because numerical seismic simulation and migration test help us accurately interpret CO2 migration. In this study, we apply the reverse-time migration and Kirchhoff migration to synthetic seismic monitoring data generated for the simplified model based on the geological structures of Ulleung basin in Korea. Synthetic seismic monitoring data are generated for various cases of CO2 migration in the subsurface. From the seismic migration images, we can investigate CO2 diffusion patterns indirectly. From seismic monitoring simulation, it is noted that while the reverse-time migration generates clear subsurface images when subsurface structures are steeply dipping, Kirchhoff migration has an advantage in imaging horizontal-layered structures such as depositional sediments appearing in the continental shelf. The reverse-time migration and Kirchhoff migration present reliable subsurface images for the potential site characterized by stratigraphical traps. In case of
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Breast Cancer Cell Colonization of the Human Bone Marrow Adipose Tissue Niche.
Templeton, Zach S; Lie, Wen-Rong; Wang, Weiqi; Rosenberg-Hasson, Yael; Alluri, Rajiv V; Tamaresis, John S; Bachmann, Michael H; Lee, Kitty; Maloney, William J; Contag, Christopher H; King, Bonnie L
2015-12-01
Bone is a preferred site of breast cancer metastasis, suggesting the presence of tissue-specific features that attract and promote the outgrowth of breast cancer cells. We sought to identify parameters of human bone tissue associated with breast cancer cell osteotropism and colonization in the metastatic niche. Migration and colonization patterns of MDA-MB-231-fLuc-EGFP (luciferase-enhanced green fluorescence protein) and MCF-7-fLuc-EGFP breast cancer cells were studied in co-culture with cancellous bone tissue fragments isolated from 14 hip arthroplasties. Breast cancer cell migration into tissues and toward tissue-conditioned medium was measured in Transwell migration chambers using bioluminescence imaging and analyzed as a function of secreted factors measured by multiplex immunoassay. Patterns of breast cancer cell colonization were evaluated with fluorescence microscopy and immunohistochemistry. Enhanced MDA-MB-231-fLuc-EGFP breast cancer cell migration to bone-conditioned versus control medium was observed in 12/14 specimens (P = .0014) and correlated significantly with increasing levels of the adipokines/cytokines leptin (P = .006) and IL-1β (P = .001) in univariate and multivariate regression analyses. Fluorescence microscopy and immunohistochemistry of fragments underscored the extreme adiposity of adult human bone tissues and revealed extensive breast cancer cell colonization within the marrow adipose tissue compartment. Our results show that breast cancer cells migrate to human bone tissue-conditioned medium in association with increasing levels of leptin and IL-1β, and colonize the bone marrow adipose tissue compartment of cultured fragments. Bone marrow adipose tissue and its molecular signals may be important but understudied components of the breast cancer metastatic niche. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
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Xu, Yanjie; Gong, Peng; Wielstra, Ben; Si, Yali
2016-08-01
The highly pathogenic avian influenza subtype H5N1 (HPAI H5N1) is a worldwide zoonotic infectious disease, threatening humans, poultry and wild birds. The role of wild birds in the spread of HPAI H5N1 has previously been investigated by comparing disease spread patterns with bird migration routes. However, the different roles that the southward autumn and northward spring migration might play in virus transmission have hardly been explored. Using direction analysis, we analyze HPAI H5N1 transmission directions and angular concentration of currently circulating viral clades, and compare these with waterfowl seasonal migration directions along major waterfowl flyways. Out of 22 HPAI H5N1 transmission directions, 18 had both a southward direction and a relatively high concentration. Differences between disease transmission and waterfowl migration directions were significantly smaller for autumn than for spring migration. The four northward transmission directions were found along Asian flyways, where the initial epicenter of the virus was located. We suggest waterfowl first picked up the virus from East Asia, then brought it to the north via spring migration, and then spread it to other parts of world mainly by autumn migration. We emphasize waterfowl autumn migration plays a relatively important role in HPAI H5N1 transmission compared to spring migration.
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International Nuclear Information System (INIS)
Ceccarelli, Simona; Cardinali, Giorgia; Aspite, Nicaela; Picardo, Mauro; Marchese, Cinzia; Torrisi, Maria Rosaria; Mancini, Patrizia
2007-01-01
Keratinocyte growth factor (KGF/FGF7) and fibroblast growth factor 10 (FGF10/KGF2) regulate keratinocyte proliferation and differentiation by binding to the tyrosine kinase KGF receptor (KGFR). KGF induces keratinocyte motility and cytoskeletal rearrangement, whereas a direct role of FGF10 on keratinocyte migration is not clearly established. Here we analyzed the motogenic activity of FGF10 and KGF on human keratinocytes. Migration assays and immunofluorescence of actin cytoskeleton revealed that FGF10 is less efficient than KGF in promoting migration and exerts a delayed effect in inducing lamellipodia and ruffles formation. Both growth factors promoted phosphorylation and subsequent membrane translocation of cortactin, an F-actin binding protein involved in cell migration; however, FGF10-induced cortactin phosphorylation was reduced, more transient and delayed with respect to that promoted by KGF. Cortactin phosphorylation induced by both growth factors was Src-dependent, while its membrane translocation and cell migration were blocked by either Src and PI3K inhibitors, suggesting that both pathways are involved in KGF- and FGF10-dependent motility. Furthermore, siRNA-mediated downregulation of cortactin inhibited KGF- and FGF10-induced migration. These results indicate that cortactin is involved in keratinocyte migration promoted by both KGF and FGF10
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Cross-continental patterns in the timing of southward Peregrine Falcon migration in North America
Worcester, R.; Ydenberg, R.C.
2008-01-01
We analyzed the timing of southward migration of Peregrine Falcons (Falco peregrinus) across North America, based on passage data compiled by the Hawk Migration Association of North America, supplemented with two other similar datasets collected by individual observers at sites in western Canada.
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Mece, Merita H.
2016-01-01
Irregular migration on the Western Balkan route has marked an unprecedented number during the last five years. Evidence indicates that both, non-European nationals and Western Balkan citizens have been involved in this complex migratory flow being exposed to various risks of human trafficking. But Western Balkan countries are source, transit and destination countries of human trafficking while their states are not well organized to implement a comprehensive and well-coordinated regional respo...
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MIGRATION PATTERNS, USE OF STOPOVER AREAS, AND AUSTRAL SUMMER MOVEMENTS OF SWAINSON'S HAWKS.
Kochert, Michael N; Fuller, Mark R; Schueck, Linda S; Bond, Laura; Bechard, Marc J; Woodbridge, Brian; Holroyd, Geoff; Martell, Mark; Banasch, Ursula
From 1995-1998, we tracked movements of adult Swainson's Hawks ( Buteo swainsoni ) using satellite telemetry to characterize migration, important stopover areas, and austral summer movements. We tagged 46 hawks from July - September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson's Hawks basically followed three routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal austral summer area in central Argentina. North of 20° N, southward and northward tracks differed little for individuals from east of the Continental Divide but differed greatly (up to 1700 km) for individuals from west of the Continental Divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. South migration lasted 42 to 98 days, and north migration took 51 to 82 days. On south migration, 36% of the Swainson's Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio marked hawks and made stopovers 9.0 - 26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and north-central Mexico. The austral period lasted 76 to 128 days. All Swainson's Hawks used a core area in central Argentina within 23% of the 738800 km 2 austral summer range where they frequently moved long distances (up to 1600 km). Conservation of Swainson's Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons including migration stopovers.
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DEFF Research Database (Denmark)
Hjortø, Gertrud M; Kiilerich-Pedersen, Katrine; Selmeczi, David
2013-01-01
Human cytomegalovirus (HCMV)-encoded G protein-coupled-receptor US28 is believed to participate in virus dissemination through modulation of cell migration and immune evasion. US28 binds different CC chemokines and the CX3C chemokine CX3CL1. Membrane-anchored CX3CL1 is expressed by immune-activat...
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International migration: The state-sovereignty-migration nexus
Directory of Open Access Journals (Sweden)
D. Chigudu
2015-12-01
Full Text Available Commonly, international human migration is blamed for corroding states sovereignty, especially stemming from policy circles, academic literature and citizens of the host countries. This has attracted the attention of the media highlighting hazards of being a migrant, with some countries viewing migrants as enemies; and, Cuba provides a vivid case. Yet in other countries, migrants are viewed as important contributors to social and economic development, with Mexico, the Dominican Republic and India serving as examples. This article locates migrants in the framework of human rights as guided by international law without prejudice to the demands of state sovereignty, but linking the two in the context of developing international standards. Migration is seen as a feature of human history dating back to primordial time. Nothing appears surprising in the movement of people across borders, defining a migrant through emigration and immigration while giving due respect to the sovereignty of states, both sending and receiving. The article discusses the nexus between migrants and state sovereignty in order to highlight the mutual benefit grounded in international law. It attempts to portray a more positive image of the migrant person in light of the global world, socio-economic development and human rights fundamentals. The main challenge remains that of implementing human rights, which appear to be at the crossroads of individual rights and state sovereignty. The paper reveals how the challenge can be overcome while maintaining the structure of rights and freedoms without infringement on states’ sovereignty. It concludes that migrants remain on the periphery of effective protection from the vagaries of the citizens, partly because the state has a tendency to confine certain rights to its citizenry. States possess discretionary authority to control the ingress of foreign nationals into their territories though sometimes they fail to do that as evidenced
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In silico pattern-based analysis of the human cytomegalovirus genome.
Rigoutsos, Isidore; Novotny, Jiri; Huynh, Tien; Chin-Bow, Stephen T; Parida, Laxmi; Platt, Daniel; Coleman, David; Shenk, Thomas
2003-04-01
More than 200 open reading frames (ORFs) from the human cytomegalovirus genome have been reported as potentially coding for proteins. We have used two pattern-based in silico approaches to analyze this set of putative viral genes. With the help of an objective annotation method that is based on the Bio-Dictionary, a comprehensive collection of amino acid patterns that describes the currently known natural sequence space of proteins, we have reannotated all of the previously reported putative genes of the human cytomegalovirus. Also, with the help of MUSCA, a pattern-based multiple sequence alignment algorithm, we have reexamined the original human cytomegalovirus gene family definitions. Our analysis of the genome shows that many of the coded proteins comprise amino acid combinations that are unique to either the human cytomegalovirus or the larger group of herpesviruses. We have confirmed that a surprisingly large portion of the analyzed ORFs encode membrane proteins, and we have discovered a significant number of previously uncharacterized proteins that are predicted to be G-protein-coupled receptor homologues. The analysis also indicates that many of the encoded proteins undergo posttranslational modifications such as hydroxylation, phosphorylation, and glycosylation. ORFs encoding proteins with similar functional behavior appear in neighboring regions of the human cytomegalovirus genome. All of the results of the present study can be found and interactively explored online (http://cbcsrv.watson.ibm.com/virus/).
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International Nuclear Information System (INIS)
Zhang, Shuai; Zou, Lihui; Yang, Ting; Yang, Yuanhua; Zhai, Zhenguo; Xiao, Fei; Wang, Chen
2015-01-01
Background: Different types of pulmonary hypertension (PH) share the same process of pulmonary vascular remodeling, the molecular mechanism of which is not entirely clarified by far. The abnormal biological behaviors of pulmonary arterial smooth muscle cells (PASMCs) play an important role in this process. Objectives: We investigated the regulation of plasminogen activator inhibitor-2 (PAI-2) by the sGC activator, and explored the effect of PAI-2 on PASMCs proliferation, apoptosis and migration. Methods: After the transfection with PAI-2 overexpression vector and specific siRNAs or treatment with BAY 41-2272 (an activator of sGC), the mRNA and protein levels of PAI-2 in cultured human PASMCs were detected, and the proliferation, apoptosis and migration of PASMCs were investigated. Results: BAY 41-2272 up regulated the endogenous PAI-2 in PASMCs, on the mRNA and protein level. In PAI-2 overexpression group, the proliferation and migration of PASMCs were inhibited significantly, and the apoptosis of PASMCs was increased. In contrast, PAI-2 knockdown with siRNA increased PASMCs proliferation and migration, inhibited the apoptosis. Conclusions: PAI-2 overexpression inhibits the proliferation and migration and promotes the apoptosis of human PASMCs. Therefore, sGC activator might alleviate or reverse vascular remodeling in PH through the up-regulation of PAI-2. - Highlights: • sGC activator BAY41-2272 up regulated PAI-2 in PASMCs, on the mRNA and protein level. • PAI-2 overexpression inhibits the proliferation and migration of human PASMCs. • PAI-2 overexpression promotes the apoptosis of human PASMCs. • sGC activator might alleviate the vascular remodeling in pulmonary hypertension
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Energy Technology Data Exchange (ETDEWEB)
Zhang, Shuai [Beijing Institute of Respiratory Medicine, Beijing Chao-yang Hospital, Capital Medical University, 8 Gongti South Rd, Beijing (China); Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, 8 Gongti South Rd, Beijing (China); Zou, Lihui [Institute of Geriatrics, Beijing Hospital, 1 Dahua Rd, Beijing (China); National Clinical Research Center for Respiratory Diseases, 1 Dahua Rd, Beijing (China); Yang, Ting; Yang, Yuanhua; Zhai, Zhenguo [Beijing Institute of Respiratory Medicine, Beijing Chao-yang Hospital, Capital Medical University, 8 Gongti South Rd, Beijing (China); Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, 8 Gongti South Rd, Beijing (China); Xiao, Fei [Institute of Geriatrics, Beijing Hospital, 1 Dahua Rd, Beijing (China); National Clinical Research Center for Respiratory Diseases, 1 Dahua Rd, Beijing (China); Wang, Chen, E-mail: chenwangcjfh@163.com [Beijing Institute of Respiratory Medicine, Beijing Chao-yang Hospital, Capital Medical University, 8 Gongti South Rd, Beijing (China); Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, 8 Gongti South Rd, Beijing (China); National Clinical Research Center for Respiratory Diseases, 1 Dahua Rd, Beijing (China)
2015-03-15
Background: Different types of pulmonary hypertension (PH) share the same process of pulmonary vascular remodeling, the molecular mechanism of which is not entirely clarified by far. The abnormal biological behaviors of pulmonary arterial smooth muscle cells (PASMCs) play an important role in this process. Objectives: We investigated the regulation of plasminogen activator inhibitor-2 (PAI-2) by the sGC activator, and explored the effect of PAI-2 on PASMCs proliferation, apoptosis and migration. Methods: After the transfection with PAI-2 overexpression vector and specific siRNAs or treatment with BAY 41-2272 (an activator of sGC), the mRNA and protein levels of PAI-2 in cultured human PASMCs were detected, and the proliferation, apoptosis and migration of PASMCs were investigated. Results: BAY 41-2272 up regulated the endogenous PAI-2 in PASMCs, on the mRNA and protein level. In PAI-2 overexpression group, the proliferation and migration of PASMCs were inhibited significantly, and the apoptosis of PASMCs was increased. In contrast, PAI-2 knockdown with siRNA increased PASMCs proliferation and migration, inhibited the apoptosis. Conclusions: PAI-2 overexpression inhibits the proliferation and migration and promotes the apoptosis of human PASMCs. Therefore, sGC activator might alleviate or reverse vascular remodeling in PH through the up-regulation of PAI-2. - Highlights: • sGC activator BAY41-2272 up regulated PAI-2 in PASMCs, on the mRNA and protein level. • PAI-2 overexpression inhibits the proliferation and migration of human PASMCs. • PAI-2 overexpression promotes the apoptosis of human PASMCs. • sGC activator might alleviate the vascular remodeling in pulmonary hypertension.
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Cyclic grain boundary migration during high temperature fatigue--I: microstructural observations
International Nuclear Information System (INIS)
Langdon, T.G.; Gifkins, R.S.
1983-01-01
Experiments were conducted on high purity lead at room temperature using reverse bending and torsion fatigue at low cyclic frequencies (less than or equal to1.50 Hz). Metallographic observations after testing show that there is a one-to-one correspondence between the markings from grain boundary migration and the number and pattern of cyclic loading, and this correspondence is maintained up to >100 cycles. Grain boundary sliding occurs in each cycle in addition to the migration, and this leads to the development of broad triple point folds. If the strain amplitude is maintained constant, it is shown that the average distance migrated in each cycle increases as the imposed frequency is decreased. The distance migrated is often exceptionally large in the first cycle of testing, and there is often a similar large initial displacement if the test is interrupted for periods of time from 1 to 24 h and then continued. For large grain sizes (greater than or equal to 2000μm), the migration markings may lead to a zig-zag pattern where the individual segments lie fairly close to 45 0 to the stress axis. A model is described which accounts for the one-to-one correspondence and which is consistent with a fine structure observed within the migration markings
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Paradox of Migration in Kolkata: A Megacity in GBM Delta
Das, S.; Hazra, S.; Ghosh, T.
2015-12-01
Contrary to other coastal cities (Mumbai, Chennai, Bhubaneswar etc.) in India, Kolkata, the largest city of India until 1990, has been showing a persistent trend of out-migration over the last decade. The situation is more paradoxical when compared to Dhaka in Bangladesh, the other coastal city in Ganga-Brahmaputra-Meghna (GBM) delta. Exacerbating impacts of Climate Change like accelerated sea level rise, impact of cyclones, rising temperature and high rainfall events and waterlogging, vis-à-vis the density of poor population in slums, Kolkata has been assessed as one of the most vulnerable cities of the world. However, Kolkata has long been a preferred destination for migrants for its port based economy, existence of industrial belt with labour intensive industries. The city and its surrounding districts attracted a massive influx of trans-border migrants when India and Bangladesh gained Independence in 1947 and 1971 respectively. The paper attempts to explore reasons behind the present trend of depopulation in the erstwhile preferred migration destination. This paper distinguishes between 'Kolkata City' (census district) with 4.5 million residents and 'Kolkata Megacity' which encompasses also the peri-urban areas and home to almost 14.1 million people according to Census 2011. Analysing migration as an ongoing research activity under DECCMA project, an overall 'in-migration' pattern can be deciphered in Kolkata 'megacity'. On the contrary, the Kolkata 'city' located right in the heart of the megacity exhibits negative net migration (-5.11%) i.e. high 'out-migration'. Plausible causes can be movement of people from Kolkata 'city' to peri-urban areas and satellite towns (urban to urban migration) probably due to closure of labour intensive industries, comparatively lower land prices, availability of space and accommodation, lower costs of living, development of different modes of commutation and communication. Further growth of population in the Kolkata Megacity
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Migration patterns of the Osprey Pandion haliaetus on the Eastern ...
African Journals Online (AJOL)
We analysed migration strategies of the Osprey Pandion haliaetus on the poorly studied Eastern European– East African flyway. Four adult birds were equipped with GPS-based satellite-transmitters or data-loggers in their breeding sites in Estonia (north-eastern Europe) and tracked to their wintering grounds in Africa and ...
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Human preferences for colorful birds: Vivid colors or pattern?
Lišková, Silvie; Landová, Eva; Frynta, Daniel
2015-04-29
In a previous study, we found that the shape of a bird, rather than its color, plays a major role in the determination of human preferences. Thus, in the present study, we asked whether the preferences of human respondents towards uniformly shaped, colorful birds are determined by pattern rather than color. The experimental stimuli were pictures of small passerine birds of the family Pittidae possessing uniform shape but vivid coloration. We asked 200 participants to rank 43 colored and 43 identical, but grayscaled, pictures of birds. To find the traits determining human preferences, we performed GLM analysis in which we tried to explain the mean preference ranks and PC axes by the following explanatory variables: the overall lightness and saturation, edges (pattern), and the portion of each of the basic color hues. The results showed that the mean preference ranks of the grayscale set is explained mostly by the birds' pattern, whereas the colored set ranking is mostly determined by the overall lightness. The effect of colors was weaker, but still significant, and revealed that people liked blue and green birds. We found no significant role of the color red, the perception of which was acquired relatively recently in evolution.
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Human Preferences for Colorful Birds: Vivid Colors or Pattern?
Directory of Open Access Journals (Sweden)
Silvie Lišková
2015-04-01
Full Text Available In a previous study, we found that the shape of a bird, rather than its color, plays a major role in the determination of human preferences. Thus, in the present study, we asked whether the preferences of human respondents towards uniformly shaped, colorful birds are determined by pattern rather than color. The experimental stimuli were pictures of small passerine birds of the family Pittidae possessing uniform shape but vivid coloration. We asked 200 participants to rank 43 colored and 43 identical, but grayscaled, pictures of birds. To find the traits determining human preferences, we performed GLM analysis in which we tried to explain the mean preference ranks and PC axes by the following explanatory variables: the overall lightness and saturation, edges (pattern, and the portion of each of the basic color hues. The results showed that the mean preference ranks of the grayscale set is explained mostly by the birds' pattern, whereas the colored set ranking is mostly determined by the overall lightness. The effect of colors was weaker, but still significant, and revealed that people liked blue and green birds. We found no significant role of the color red, the perception of which was acquired relatively recently in evolution.
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DEFF Research Database (Denmark)
Petersen, Jens Højslev; Naamansen, Ebbe Tubæk; Nielsen, Preben Aagård
1995-01-01
experiment samples of cheese of the types most commonly consumed in Denmark were wrapped in this 'low migration' PVC film using a procedure simulating the actual pattern of use in retail shops. After a storage time of 2 h at 5 degrees C the level of DEHA was 45 mg/kg of cheese, which after 10 days increased...... of DEHA close to or above the tolerable daily intake of 0.3 mg/kg body weight as defined by the EEC Scientific Committee for Food. Furthermore, it is stressed that measurements of global migration followed by uncritical use of reduction factors may result in erroneous evaluation of the suitability of DEHA-plasticized......Following exposure to the food simulant olive oil for 10 days at 5, 20 or 40 degrees C a global migration ranging from 20 to 30 mg/dm(2) was detected from a common 'low migration' PVC film plasticized with a mixture of di-(ethylhexyl)adipate (DEHA) and a polymeric plasticizer. In a laboratory...
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MIGRATION EFFECTS ON THE EDUCATIONAL ENVIRONMENT
Directory of Open Access Journals (Sweden)
Luminița\tCORBU
2015-06-01
Full Text Available In this paper we propose to present the current migration patterns and consequences which they have on the economical and social life in Romania. Romania's integration in the European Union had numerous benefits, meaning that it opened gates to new jobs and to new systems of education. This paper aims to highlight the demographic, social, economical and educational effects of migration on the population of Romania. There is a social impact on the lives of migrant families, especially the temporary abandonment of minors by migrant parents, low academic achievement, early school leaving and adopting inadequately behaviors in society.
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Green migration into rural America: The new frontier of environmentalism?
Robert Emmet Jones; J. Mark Fly; James Talley; H. Ken Cordell
2003-01-01
This article proposes that shifts in rural population and economic growth patterns may help explain rising levels of support for environmental values in many rural areas. In particular, it assesses a model of "green migration" that assumes that domestic in-migration, with its impacts on the character and composition of rural communities, is one of the reasons...
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Moving Across Boundaries: Migration in South Africa, 1950–2000
2013-01-01
Existing knowledge about historical patterns of black internal migration in South Africa is incomplete, primarily because of the lack of good life course studies as well as the apartheid government’s suppression and censoring of data. This article provides a comprehensive picture of historical internal migration patterns with an analysis of a unique individual retrospective life history data set. This sample of the black population, collected in 2000, is the only known nationally representative life history data for South Africa; it includes all residential moves for each individual during his/her lifetime. Various mobility outcomes are analyzed: moves within/across provinces, moves within/across rural and urban areas, forced moves, moves with a nuclear family, and individual moves. The results indicate that migration significantly increased among black South Africans during the last half of the twentieth century, and that this increase began before the Pass Laws were repealed in 1986 and well before the official end of apartheid in 1991 or the first free election in 1994. The timing of this increase in migration rates suggests that migration in defiance of the Pass Laws (albeit a dangerous and desperate proposition) was a way of life for many black South Africans. PMID:22956415
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Influenza a virus migration and persistence in North American wild birds.
Directory of Open Access Journals (Sweden)
Justin Bahl
Full Text Available Wild birds have been implicated in the emergence of human and livestock influenza. The successful prediction of viral spread and disease emergence, as well as formulation of preparedness plans have been hampered by a critical lack of knowledge of viral movements between different host populations. The patterns of viral spread and subsequent risk posed by wild bird viruses therefore remain unpredictable. Here we analyze genomic data, including 287 newly sequenced avian influenza A virus (AIV samples isolated over a 34-year period of continuous systematic surveillance of North American migratory birds. We use a Bayesian statistical framework to test hypotheses of viral migration, population structure and patterns of genetic reassortment. Our results reveal that despite the high prevalence of Charadriiformes infected in Delaware Bay this host population does not appear to significantly contribute to the North American AIV diversity sampled in Anseriformes. In contrast, influenza viruses sampled from Anseriformes in Alberta are representative of the AIV diversity circulating in North American Anseriformes. While AIV may be restricted to specific migratory flyways over short time frames, our large-scale analysis showed that the long-term persistence of AIV was independent of bird flyways with migration between populations throughout North America. Analysis of long-term surveillance data provides vital insights to develop appropriately informed predictive models critical for pandemic preparedness and livestock protection.
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DEFF Research Database (Denmark)
Rauwel, Benjamin; Mariamé, Bernard; Martin, Hélène
2010-01-01
, as assessed by using well-established in vitro models of invasive trophoblast i.e. primary cultures of EVCT isolated from first trimester placentas and the EVCT-derived cell line HIPEC. Our data provide new clues to explain how early infection during pregnancy could impair implantation, placentation...... and chromatin immunoprecipitation assays. Due to the key role of PPARgamma in placentation and its specific trophoblast expression within the human placenta, we then provided evidence that by activating PPARgamma human cytomegalovirus dramatically impaired early human trophoblast migration and invasiveness...
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Pilkington, Suzanne M; Ogden, Stephanie; Eaton, Laura H; Dearman, Rebecca J; Kimber, Ian; Griffiths, Christopher E M
2018-01-01
Langerhans' cells (LC) play pivotal roles in skin immune responses, linking innate and adaptive immunity. In aged skin there are fewer LC and migration is impaired compared with young skin. These changes may contribute to declining skin immunity in the elderly, including increased skin infections and skin cancer. Interleukin-1β (IL-1β) and tumour necrosis factor-α (TNF-α) are mandatory signals for LC migration and previous studies suggest that IL-1β signalling may be dysregulated in aged skin. Therefore, we sought to explore the mechanisms underlying these phenomena. In skin biopsies of photoprotected young ( 70 years) human skin ex vivo, we assessed the impact of trauma, and mandatory LC mobilizing signals on LC migration and gene expression. Biopsy-related trauma induced LC migration from young epidermis, whereas in aged skin, migration was greatly reduced. Interleukin-1β treatment restored LC migration in aged epidermis whereas TNF-α was without effect. In uncultured, aged skin IL-1β gene expression was lower compared with young skin; following culture, IL-1βmRNA remained lower in aged skin under control and TNF-α conditions but was elevated after culture with IL-1β. Interleukin-1 receptor type 2 (IL1R2) gene expression was significantly increased in aged, but not young skin, after cytokine treatment. Keratinocyte-derived factors secreted from young and aged primary cells did not restore or inhibit LC migration from aged and young epidermis, respectively. These data suggest that in aged skin, IL-1β signalling is diminished due to altered expression of IL1B and decoy receptor gene IL1R2. © 2017 The Authors. Immunology Published by John Wiley & Sons Ltd., Immunology.
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Alowayed, Nour; Salker, Madhuri S; Zeng, Ni; Singh, Yogesh; Lang, Florian
2016-01-01
LEFTY2, a suppressor of cell proliferation, tumor growth, regulator of stemness and embryonic differentiation, is a negative regulator of cancer cell reprogramming. Malignant transformation may lead to migration requiring loss of adhesion and gain of migratory activity. Signaling involved in the orchestration of migration, proliferation and spreading of cells include focal adhesion kinase (FAK) and adhesion molecule E-cadherin. The present study explored whether LEFTY2 influences the proliferation marker MKi67, FAK activity, E-cadherin abundance and migration of Ishikawa human endometrial carcinoma cells. Moreover, the study explored the involvement of microRNA-200a (miR-200a), which is known to regulate cellular adhesion by targeting E-Cadherin. FAK activity was estimated from FAK phosphorylation quantified by Western blotting, migration utilizing a wound healing assay, miR-200a and MKi67 expression levels utilizing qRT-PCR, cell proliferation and apoptosis using BrdU and Annexin V staining, respectively, and E-Cadherin (E-Cad) abundance, using confocal microscopy. LEFTY2 (25 ng/ml, 48 hours) treatment was followed by decrease of MKi67 expression, FAK activity and migration. LEFTY2 upregulated miRNA-200a and E-Cad protein level in Ishikawa cells. The effect of LEFTY2 on migration was mimicked by FAK inhibitor PF 573228 (50 µM). Addition of LEFTY2 in the presence of PF-573228 did not result in a further significant decline of migration. In conclusion, LEFTY2 down-regulates MKi67 expression and FAK activity, up-regulates miR-200a and E-cadherin, and is thus a powerful negative regulator of endometrial cell proliferation and migration. © 2016 The Author(s) Published by S. Karger AG, Basel.
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Physicists' Forced Migrations under Hitler
Beyerchen, Alan
2011-03-01
When the Nazis came to power in early 1933 they initiated formal and informal measures that forced Jews and political opponents from public institutions such as universities. Some physicists retired and others went into industry, but most emigrated. International communication and contact made emigration a viable option despite the desperate economic times in the Great Depression. Another wave of emigrations followed the annexation of Austria in 1938. Individual cases as well as general patterns of migration and adaptation to new environments will be examined in this presentation. One important result of the forced migrations was that many of the physicists expelled under Hitler played important roles in strengthening physics elsewhere, often on the Allied side in World War II.
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The mechanism for primordial germ-cell migration is conserved between Japanese eel and zebrafish.
Directory of Open Access Journals (Sweden)
Taiju Saito
Full Text Available Primordial germ cells (PGCs are segregated and specified from somatic cells during early development. These cells arise elsewhere and have to migrate across the embryo to reach developing gonadal precursors. Several molecules associated with PGC migration (i.e. dead-end, nanos1, and cxcr4 are highly conserved across phylum boundaries. However, since cell migration is a complicated process that is regulated spatially and temporally by multiple adaptors and signal effectors, the process is unlikely to be explained by these known genes only. Indeed, it has been shown that there are variations in PGC migration pattern during development among teleost species. However, it is still unclear whether the actual mechanism of PGC migration is conserved among species. In this study, we studied the migration of PGCs in Japanese eel (Anguilla japonica embryos and tested the migration mechanism between Japanese eel and zebrafish (Danio rerio for conservation, by transplanting eel PGCs into zebrafish embryos. The experiments showed that eel PGCs can migrate toward the gonadal region of zebrafish embryos along with endogenous PGCs, even though the migration patterns, behaviors, and settlements of PGCs are somewhat different between these species. Our results demonstrate that the migration mechanism of PGCs during embryonic development is highly conserved between these two distantly related species (belonging to different teleost orders.
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Liu, Hongyu; Jiang, Yue; Jin, Xiaoyan; Zhu, Lihua; Shen, Xiaoyue; Zhang, Qun; Wang, Bin; Wang, Junxia; Hu, Yali; Yan, Guijun; Sun, Haixiang
2013-07-15
Matrix metalloproteinase 2 (MMP-2) has been reported to be an important regulator of cell migration and invasion through degradation of the extracellular matrix (ECM) in many diseases, such as cancer and endometriosis. Here, we found calcium-activated neutral protease 7 (CAPN 7) expression was markedly upregulated in the eutopic endometrium and endometrial stromal cells of women diagnosed with endometriosis. Our studies were carried out to detect the effects of CAPN 7 on human endometrial stromal cell (hESC) migration and invasion. Western blotting and quantitative real-time PCR were used to detect the expression of CAPN 7 in endometriosis patients and normal fertile women. Scratch-wound-healing and invasion chamber assay were used to investigate the role of CAPN 7 in hESC migration and invasion. Western blotting, quantitative real-time PCR and zymography were carried out to detect the effect of CAPN 7 on the expressions and activity of MMP-2. CAPN 7 was markedly up-regulated in endometriosis, thereby promoting the migration and invasion of hESC. CAPN 7 overexpression led to increased expression of MMP-2 and tissue inhibitor of metalloproteinases 2 (TIMP-2); CAPN 7 knockdown reversed these changes. CAPN 7 increased MMP-2 activity by increasing the ratio of MMP-2 to TIMP-2. We also found that OA-Hy (an MMP-2 inhibitor) decreased the effects of CAPN 7 overexpression on hESC migration and invasion by approximately 50% and 55%, respectively. Additionally, a coimmunoprecipitation assay demonstrated that CAPN 7 interacted with activator protein 2α (AP-2α): an important transcription factor of MMP-2. CAPN 7 promotes hESC migration and invasion by increasing the activity of MMP-2 via an increased ratio of MMP-2 to TIMP-2.
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Uncovering stable and occasional human mobility patterns: A case study of the Beijing subway
Yong, Nuo; Ni, Shunjiang; Shen, Shifei; Chen, Peng; Ji, Xuewei
2018-02-01
There have generally been two kinds of approaches to the empirical study of human mobility. At the group level, some valuable information might be submerged in statistical noise, while due to the diversity of individual purpose and preference, there is still no general statistical regularity of human mobility at the individual level. In this paper, we considered group-level human mobility as the combination of several basic patterns and analyzed the collective mobility by category. Utilizing matrix factorization and correlation analysis, we extracted some of the stable/occasional components from the collective human mobility in the Beijing subway and found that the departure and arrival mobility patterns have different characteristics, both in time and space, under various conditions. We classified individual records into different patterns and analyzed the most likely trip distance by category. The proposed method can decompose stable/occasional mobility patterns from the collective mobility and identify passengers belonging to different patterns, helping us to better understand the origin of different mobility patterns and provide guidance for emergency management of large crowds.
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Hormone patterns in early human gestation
International Nuclear Information System (INIS)
Mishell, D.R. Jr.; Thorneycroft, I.H.; Nagata, Y.; Murata, T.; Nakamura, R.M.
1974-01-01
Accurate measurement of the low concentration of gonadotropins and steroid hormones present in human serum has been made possible by the development of sensitive radioimmunoassay (RIA) techniques. With the use of RIA FSH and LH, progesterone and 17OH-progesterone have been previously measured in early normal pregnancy. In order to determine the daily pattern of hormone levels in early normal pregnancy, gonadotropins as well as steroid hormone levels were measured in serum samples obtained daily from three women from the time of the last menstrual period prior to conception throughout the first few months of gestation. To further identify the steroid hormone pattern in early normal pregnancy, concentrations of estradiol, progesterone, and 17OH-progesterone were measured in individual serum samples obtained from a group of 158 women with apparently normal gestations who subsequently had therapeutic abortions. (auth)
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Ballard, Roger
1990-01-01
The paper contains an exploration of the reasons why rules of clan exogamy followed by Punjabi Hindus and Sikhs, as opposed to the Mirpuri Muslim preference for close kin marriage, have had such a far-reaching impact on patterns of migration to, and resettlement in, Britain.
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Collinson, Mark A; Tollman, Stephen M; Kahn, Kathleen
2007-08-01
World population growth will be increasingly concentrated in the urban areas of the developing world; however, some scholars caution against the oversimplification of African urbanization noting that there may be "counter-urbanization" and a prevailing pattern of circular rural-urban migration. The aim of the paper is to examine the ongoing urban transition in South Africa in the post-apartheid period, and to consider the health and social policy implications of prevailing migration patterns. Two data sets were analysed, namely the South African national census of 2001 and the Agincourt health and demographic surveillance system. A settlement-type transition matrix was constructed on the national data to show how patterns of settlement have changed in a five-year period. Using the sub-district data, permanent and temporary migration was characterized, providing migration rates by age and sex, and showing the distribution of origins and destinations. The comparison of national and sub-district data highlight the following features: urban population growth, particularly in metropolitan areas, resulting from permanent and temporary migration; prevailing patterns of temporary, circular migration, and a changing gender balance in this form of migration; stepwise urbanization; and return migration from urban to rural areas. Policy concerns include: rural poverty exacerbated by labour migration; explosive conditions for the transmission of HIV; labour migrants returning to die in rural areas; and the challenges for health information created by chronically ill migrants returning to rural areas to convalesce. Lastly, suggestions are made on how to address the dearth of relevant population information for policy-making in the fields of migration, settlement change and health.
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Lee, Hee Doo; Kim, Yeon Hyang; Kim, Doo-Sik
2014-04-01
Integrin trafficking, including internalization, recycling, and lysosomal degradation, is crucial for the regulation of cellular functions. Exosomes, nano-sized extracellular vesicles, are believed to play important roles in intercellular communications. This study demonstrates that exosomes released from human macrophages negatively regulate endothelial cell migration through control of integrin trafficking. Macrophage-derived exosomes promote internalization of integrin β1 in primary HUVECs. The internalized integrin β1 persistently accumulates in the perinuclear region and is not recycled back to the plasma membrane. Experimental results indicate that macrophage-derived exosomes stimulate trafficking of internalized integrin β1 to lysosomal compartments with a corresponding decrease in the integrin destined for recycling endosomes, resulting in proteolytic degradation of the integrin. Moreover, ubiquitination of HUVEC integrin β1 is enhanced by the exosomes, and exosome-mediated integrin degradation is blocked by bafilomycin A, a lysosomal degradation inhibitor. Macrophage-derived exosomes were also shown to effectively suppress collagen-induced activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway and HUVEC migration, which are both dependent on integrin β1. These observations provide new insight into the functional significance of exosomes in the regulation of integrin trafficking. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Data and methods in the environment-migration nexus
DEFF Research Database (Denmark)
Eklund, Lina; Romankiewicz, Clemens; Brandt, Martin Stefan
2016-01-01
The relationship between environment and migration has gained increased attention since the 1990s when the Intergovernmental Panel on Climate Change projected climate change to become a major driver of human migration. Evaluations of this relationship include both quantitative and qualitative ass....... Several case studies base their results on data at very coarse resolutions that have undergone strong modifications and generalizations. We argue that scale-related shortcomings must be considered in all stages of environment-migration research....... assessments. This review article introduces the concept of scale to environment-migration research as an important methodological issue for the reliability of conclusions drawn. The review of case studies shows that scale issues are highly present in environment-migration research but rarely discussed...
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Nagatani, Takashi; Tainaka, Kei-ichi
2018-01-01
In most cases, physicists have studied the migration of biospecies by the use of random walk. In the present article, we apply cellular automaton of traffic model. For simplicity, we deal with an ecosystem contains a prey and predator, and use one-dimensional lattice with two layers. Preys stay on the first layer, but predators uni-directionally move on the second layer. The spatial and temporal evolution is numerically explored. It is shown that the migration has the important effect on populations of both prey and predator. Without migration, the phase transition between a prey-phase and coexisting-phase occurs. In contrast, the phase transition disappears by migration. This is because predator can survive due to migration. We find another phase transition for spatial distribution: in one phase, prey and predator form a stripe pattern of condensation and rarefaction, while in the other phase, they uniformly distribute. The self-organized stripe may be similar to the migration patterns in real ecosystems.
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Gendered Migration and the Urban Informal Sector: A Case Study of ...
African Journals Online (AJOL)
This study examined gendered migration patterns in Mwanza City, Tanzania as well as the impacts of differentials of men's and women's migration on their absorption in the urban informal sector, their access to assets, adaptation to city life and their livelihood and also their role in development of origin areas. The study ...
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[Peptide fragments of chemokine domain of fractalkine: effect on human monocyte migration].
Kukhtina, N B; Aref'eva, T I; Ruleva, N Iu; Sidorova, M V; Az'muko, A A; Bespalova, Zh D; Krasnikova, T L
2012-01-01
Leukocyte chemotaxis to the area of tissue damage is mediated by chemokines. According to the primary structure, chemokines are divided into four families, fractalkine (CX3CL1) is the only one member of CX3C family and the only membrane-bound chemokine. Fractalkine molecule includes the extracellular N-terminal chemokine domain, mucin-like rod, the transmembrane and the intracellular domains. In membrane-bound state fractalkine has the properties of an adhesion molecule. Chemokine domain of fractalkine (CDF) is released from cell membrane by proteolysis, and this soluble form acts as a chemoattractant for leukocytes expressing fractalkine receptor CX3CR1. Fractalkine is involved in development of a number of pathological processes caused by inflammation, and therefore a search for fractalkine inhibitors is very important. For this purpose we identified several antigenic determinants--the fragments of CDF, and the following peptides were synthesized--P41-52 H-Leu-Glu-Thr-Arg-Gln-His-Arg-Leu-Phe-Cys-Ala-Asp-NH2, P53-60 H-Pro-Lys-Glu-Gln-Trp-Val-Lys-Asp-NH2 and P60-71 H-Asp-Ala-Met-Gln-His-Leu-Asp-Arg-Gln-Ala-Ala-Ala-NH2. The peptide effects on adhesion and migration of human peripheral blood monocytes expressing fractalkine receptors were investigated. In the presence of CDF and P41-52 we observed the increased adhesion and migration of monocytes compared with spontaneous values. Peptides P53-60 and P60-71 significantly inhibited monocyte adhesion and migration stimulated by CDF. Since the chemotactic activity of chemokines was shown to be dependent on their binding to glycosaminoglycans of the cell surface and extracellular matrix, the effect ofpeptides on the interaction of CDF with heparin was analyzed by ELISA. Peptide P41-52 competed with CDF for heparin binding, while peptides P53-60 and P60-71 had no significant activity.
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Rural migration in Nevada: Lincoln County. Phase 1, 1992--1993
Energy Technology Data Exchange (ETDEWEB)
Soden, D.L.; Carns, D.E.; Mosser, D.; Conary, J.S.; Ansell, J.P.
1993-12-31
The principal objective of this project was to develop insight into the scope of migration of working age Nevadans out of their county of birth; including the collection of data on their skill levels, desire to out or in-migrate, interactions between families of migratory persons, and the impact that the proposed high-level nuclear waste repository at Yucca mountain might have on their individual, and collective, decisions to migrate and return. The initial phase of this project reported here was conducted in 1992 and 1993 in Lincoln County, Nevada, one of the counties designated as ``affected`` by the proposed repository program. The findings suggest that a serious out-migration problem exists in Lincoln County, and that the Yucca mountain project will likely affect decisions relating to migration patterns in the future.
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An analysis of African female migration to South Africa: The case of ...
African Journals Online (AJOL)
As with every social phenomenon, migration has a gender dimension, and a gender analysis is therefore pertinent in understanding African migration. The nature, patterns, experiences and forms of interaction between female migrants and members of their host community has its uniqueness. The nature of interaction and ...
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Exploring Human Activity Patterns Using Taxicab Static Points
Directory of Open Access Journals (Sweden)
Bin Jiang
2012-06-01
Full Text Available This paper explores the patterns of human activities within a geographical space by adopting the taxicab static points which refer to the locations with zero speed along the tracking trajectory. We report the findings from both aggregated and individual aspects. Results from the aggregated level indicate the following: (1 Human activities exhibit an obvious regularity in time, for example, there is a burst of activity during weekend nights and a lull during the week. (2 They show a remarkable spatial drifting pattern, which strengthens our understanding of the activities in any given place. (3 Activities are heterogeneous in space irrespective of their drifting with time. These aggregated results not only help in city planning, but also facilitate traffic control and management. On the other hand, investigations on an individual level suggest that (4 activities witnessed by one taxicab will have different temporal regularity to another, and (5 each regularity implies a high level of prediction with low entropy by applying the Lempel-Ziv algorithm.
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International Nuclear Information System (INIS)
Stengel, Dominique; O'Neil, Caroline; Brocheriou, Isabelle; Karabina, Sonia-Athina; Durand, Herve; Caplice, Noel M.; Pickering, J. Geoffrey; Ninio, Ewa
2006-01-01
Platelet-activating-Factor (PAF) and its structural analogues formed upon low density lipoprotein oxidation are involved in atherosclerotic plaque formation and may signal through PAF-receptor (PAF-R) expressed in human macrophages and in certain smooth muscle cells (SMCs) in the media, but rarely in the intima of human plaques. Our aim was to determine which SMC phenotype expresses PAF-R and whether this receptor is functional in cell migration. Circulating SMC progenitors and two phenotypically distinct clones of proliferative, epithelioid phenotype vs contractile, spindle-shaped SMCs from the media of adult internal thoracic artery were studied for the presence of PAF-receptor (PAF-R). The levels of specific mRNA were obtained by reverse transcription/real-time PCR, the protein expression was deduced from immunohistochemistry staining, and the functional transmigration assay was performed by Boyden chamber-type chemotaxis assay. Only SMCs of spindle-shape and synthetic phenotype expressed both mRNA and PAF-R protein and in the functional test migrated at low concentrations of PAF. Two unrelated, specific PAF-R antagonists inhibited PAF-induced migration, but did not modify the migration initiated by PDGF. The presence of functional PAF-R in arterial spindle-shaped SMCs of synthetic phenotype may be important for their migration from the media into the intima and atherosclerotic plaques formation
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Worldwide Patterns of Ancestry, Divergence, and Admixture in Domesticated Cattle
Decker, Jared E.; McKay, Stephanie D.; Rolf, Megan M.; Kim, JaeWoo; Molina Alcalá, Antonio; Sonstegard, Tad S.; Hanotte, Olivier; Götherström, Anders; Seabury, Christopher M.; Praharani, Lisa; Babar, Masroor Ellahi; Correia de Almeida Regitano, Luciana; Yildiz, Mehmet Ali; Heaton, Michael P.; Liu, Wan-Sheng; Lei, Chu-Zhao; Reecy, James M.; Saif-Ur-Rehman, Muhammad; Schnabel, Robert D.; Taylor, Jeremy F.
2014-01-01
The domestication and development of cattle has considerably impacted human societies, but the histories of cattle breeds and populations have been poorly understood especially for African, Asian, and American breeds. Using genotypes from 43,043 autosomal single nucleotide polymorphism markers scored in 1,543 animals, we evaluate the population structure of 134 domesticated bovid breeds. Regardless of the analytical method or sample subset, the three major groups of Asian indicine, Eurasian taurine, and African taurine were consistently observed. Patterns of geographic dispersal resulting from co-migration with humans and exportation are recognizable in phylogenetic networks. All analytical methods reveal patterns of hybridization which occurred after divergence. Using 19 breeds, we map the cline of indicine introgression into Africa. We infer that African taurine possess a large portion of wild African auroch ancestry, causing their divergence from Eurasian taurine. We detect exportation patterns in Asia and identify a cline of Eurasian taurine/indicine hybridization in Asia. We also identify the influence of species other than Bos taurus taurus and B. t. indicus in the formation of Asian breeds. We detect the pronounced influence of Shorthorn cattle in the formation of European breeds. Iberian and Italian cattle possess introgression from African taurine. American Criollo cattle originate from Iberia, and not directly from Africa with African ancestry inherited via Iberian ancestors. Indicine introgression into American cattle occurred in the Americas, and not Europe. We argue that cattle migration, movement and trading followed by admixture have been important forces in shaping modern bovine genomic variation. PMID:24675901
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Micro-patterned graphene-based sensing skins for human physiological monitoring
Wang, Long; Loh, Kenneth J.; Chiang, Wei-Hung; Manna, Kausik
2018-03-01
Ultrathin, flexible, conformal, and skin-like electronic transducers are emerging as promising candidates for noninvasive and nonintrusive human health monitoring. In this work, a wearable sensing membrane is developed by patterning a graphene-based solution onto ultrathin medical tape, which can then be attached to the skin for monitoring human physiological parameters and physical activity. Here, the sensor is validated for monitoring finger bending/movements and for recognizing hand motion patterns, thereby demonstrating its future potential for evaluating athletic performance, physical therapy, and designing next-generation human-machine interfaces. Furthermore, this study also quantifies the sensor’s ability to monitor eye blinking and radial pulse in real-time, which can find broader applications for the healthcare sector. Overall, the printed graphene-based sensing skin is highly conformable, flexible, lightweight, nonintrusive, mechanically robust, and is characterized by high strain sensitivity.
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Understanding how emergencies affect internal migration in Costa ...
International Development Research Centre (IDRC) Digital Library (Canada)
2016-06-08
Jun 8, 2016 ... ... under the Latin American and Caribbean Environmental Economics Program ... and, as this research found, will in turn have an impact on migration patterns. ... Balancing trade-offs for wastewater treatment in Mexico City.
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Intrathymic laminin-mediated interactions: role in T cell migration and development
Directory of Open Access Journals (Sweden)
Wilson eSavino
2015-11-01
Full Text Available Intrathymic T cell differentiation is a key process for the development and maintenance of cell-mediated immunity, and occurs concomitantly to highly regulated migratory events. We have proposed a multivectorial model for describing intrathymic thymocyte migration. One of the individual vectors comprises interactions mediated by laminins, a heterotrimeric protein family of the extracellular matrix. Several laminins are expressed in the thymus, being produced by microenvironmental cells, particularly thymic epithelial cells. Also, thymocytes and epithelial cells express integrin-type laminin receptors. Functionally, it has been reported that the dy/dy mutant mouse (lacking the laminin isoform 211 exhibits defective thymocyte differentiation. Several data show haptotactic effects of laminins upon thymocytes, as well as their adhesion on thymic epithelial cells; both effects being prevented by anti-laminin or anti-laminin receptor antibodies. Interestingly, laminin synergizes with chemokines to enhance thymocyte migration, whereas classe-3 semaphorins and B ephrins, which exhibit chemorepulsive effects in the thymus, downregulate laminin-mediated migratory responses of thymocytes. More recently, we showed that knocking down the ITGA6 gene (which encodes the α6 integrin chain of laminin receptors in human thymic epithelial cells, modulates a large number of cell-migration related genes, and results in changes of adhesion pattern of thymocytes onto the thymic epithelium. Overall, laminin-mediated interactions can be placed at the cross-road of the multivectorial process of thymocyte migration, with a direct influence per se, as well as by modulating other molecular interactions associated with the intrathymic trafficking events.
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Neoliberal Globalization and the Politics of Migration in Sub-Saharan Africa
Directory of Open Access Journals (Sweden)
Saul Tobias
2012-11-01
Full Text Available Over the last few decades, many states in sub-Saharan Africa have adopted draconian anti-migrant policies, leaving refugees and migrants vulnerable to violence, harassment, and economic exploitation. These policies represent a shift from the relatively hospitable attitude shown by many African nations in the immediate post-colonial period. Explanations at the local level do not adequately explain the pervasiveness of these changes or why many developing states are now replicating the migration discourse and practices of the global north. Drawing on scholarship and data from a number of states in the region, including Tanzania, Kenya, Ghana, and South Africa, this paper argues that owing to the widespread implementation of neoliberal economic policies, these states are now subject to many of the same incentives and constraints that operate in the developed north. As a result, political parties and business elites have used national migration policy as an instrument for enhancing their political and economic positions. Insofar as neoliberal globalization continues to exacerbate inequality within the developing world, the harsh measures taken by governments of developing countries against their refugee and migrant populations are likely to increase. It is therefore important that scholars of migration and human rights begin to reassess the prevailing, nearly exclusive emphasis in many globalization studies on the dehumanizing policies and exploitation of southern migrants by states in the global north, as such an emphasis risks obscuring the emergence of more complex patterns of migration and anti-migrant practices in the developing world.
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Do more educated workers migrate more? Findings from the Korean Labor and Income Panel Study
Directory of Open Access Journals (Sweden)
Ye Seul Choi
2015-11-01
Full Text Available This paper examines the relationship of migration between capital regions and non-capital regions and the level of human capital in Korea using the method of multinomial logistic regression. This paper aims to show whether the high level of human capital of migrants who move to capital regions statistically differs from the other migrants. For analysis, this paper uses the 2006, 2008, 2010 and 2012 panel data from Korean Labor and Income Panel Study (KLIPS. The analysis is divided into two parts of migration based on the region of origin: the migration of individuals who live in non-capital regions and the migration of individuals who live in capital region. In this paper, we consider personal characteristics such as educational attainment and occupations as an indicator of human capital of individual, gender, age, and marriage status as explanatory variables. Our empirical finding is that the educational attainment of individual representing a level of human capital significantly affects the migration behavior moving from non-capital regions to capital regions. According to analysis of migration from Gyeonggi and Incheon to Seoul, the migration within capital regions, individuals who engage in occupation with high skilled and non-manual are more likely to move to Seoul capital regions where favorable conditions for workers in terms of higher wage and better job opportunities can provide. Those results can be understood in the context of human capital theory to maximize personal socioeconomic utilities by migrating to capital regions.
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Interregional migration of youths in Russia: a comprehensive analysis of demographic statistics
Kashnitsky, I.; Mkrtchyan, N.; Leshukov, O.V.
2016-01-01
Not dissimilar to many other countries, migration in Russia has a pronounced age-dependent pattern with the peak intensity at the age when people obtain higher and professional education. In this paper, we analyze migration intensity at student age (17–21) using three sources of demographic data
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Integrating meteorology into research on migration.
Shamoun-Baranes, Judy; Bouten, Willem; van Loon, E Emiel
2010-09-01
Atmospheric dynamics strongly influence the migration of flying organisms. They affect, among others, the onset, duration and cost of migration, migratory routes, stop-over decisions, and flight speeds en-route. Animals move through a heterogeneous environment and have to react to atmospheric dynamics at different spatial and temporal scales. Integrating meteorology into research on migration is not only challenging but it is also important, especially when trying to understand the variability of the various aspects of migratory behavior observed in nature. In this article, we give an overview of some different modeling approaches and we show how these have been incorporated into migration research. We provide a more detailed description of the development and application of two dynamic, individual-based models, one for waders and one for soaring migrants, as examples of how and why to integrate meteorology into research on migration. We use these models to help understand underlying mechanisms of individual response to atmospheric conditions en-route and to explain emergent patterns. This type of models can be used to study the impact of variability in atmospheric dynamics on migration along a migratory trajectory, between seasons and between years. We conclude by providing some basic guidelines to help researchers towards finding the right modeling approach and the meteorological data needed to integrate meteorology into their own research. © The Author 2010. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.
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Spatiotemporal Patterns of Urban Human Mobility
Hasan, Samiul; Schneider, Christian M.; Ukkusuri, Satish V.; González, Marta C.
2013-04-01
The modeling of human mobility is adopting new directions due to the increasing availability of big data sources from human activity. These sources enclose digital information about daily visited locations of a large number of individuals. Examples of these data include: mobile phone calls, credit card transactions, bank notes dispersal, check-ins in internet applications, among several others. In this study, we consider the data obtained from smart subway fare card transactions to characterize and model urban mobility patterns. We present a simple mobility model for predicting peoples' visited locations using the popularity of places in the city as an interaction parameter between different individuals. This ingredient is sufficient to reproduce several characteristics of the observed travel behavior such as: the number of trips between different locations in the city, the exploration of new places and the frequency of individual visits of a particular location. Moreover, we indicate the limitations of the proposed model and discuss open questions in the current state of the art statistical models of human mobility.
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Úbeda, Sara; Aznar, Margarita; Vera, Paula; Nerín, Cristina; Henríquez, Luis; Taborda, Laura; Restrepo, Claudia
2017-10-01
Most multilayer high barrier materials used in food packaging have a polyurethane adhesive layer in their structures. In order to assess the safety of these materials, it is important to determine the compounds intentionally added to the adhesives (IAS) as well as those non-intentionally added substances (NIAS). During the manufacture of polyurethane adhesives, some by-products can be formed, such as cyclic polyester oligomers coming from the reaction between dicarboxylic acids and glycols. Since these compounds are not listed in the Regulation 10/2011/EU, they should not be found in migration above 0.01 mg/kg of simulant. In this study two flexible multilayer packaging materials were used and migration was evaluated in simulant A (ethanol 10% v/v), simulant B (acetic acid 3% w/v) and simulant ethanol 95% v/v during 10 days at 60ºC. Identification and quantification of non-volatile compounds was carried out by UPLC-MS-QTOF. Most of migrants were oligomers such as cyclic polyesters and caprolactam oligomers. Overall migration and specific migration of adipic acid-diethylene glycol and phthalic acid-diethylene glycol were monitored over time and analysed by UPLC-MS-TQ. In most cases, ethanol 95% v/v was the simulant with the highest concentration values. Overall migration kinetics followed a similar pattern than specific migration kinetics.
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Partial migration and transient coexistence of migrants and residents in animal populations.
Singh, Navinder J; Leonardsson, Kjell
2014-01-01
Partial migration, whereby a proportion of the population migrates, is common across the animal kingdom. Much of the focus in the literature has been on trying to explain the underlying mechanisms for the coexistence of migrants and residents. In addition, there has been an increasing number of reports on the prevalence and frequency of partially migratory populations. One possible explanation for the occurrence of partial migration, which has received no attention in the literature, is that of 'transient coexistence' during the invasion phase of a superior behaviour. In this study we develop a theoretical basis for explaining partial migration as a transient coexistence and derive a method to predict the frequency of residents and migrants in partially migrating populations. This method is useful to predict the frequencies of migrants and residents in a small set of populations as a complementing hypothesis to 'an Evolutionary Stable Strategy (ESS)'. We use the logistic growth equation to derive a formula for predicting the frequencies of residents and migrants. We also use simulations and empirical data from white perch (Morone americana), moose (Alces alces) and red deer (Cervus elaphus) to demonstrate our approach. We show that the probability of detecting partial migration due to transient coexistence depends upon a minimum number of tracked or marked individuals for a given number of populations. Our approach provides a starting point in searching for explanations to the observed frequencies, by contrasting the observed pattern with both the predicted transient and the uniform random pattern. Aggregating such information on observed patterns (proportions of migrants and residents) may eventually lead to the development of a quantitative theory for the equilibrium (ESS) populations as well.
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Partial migration and transient coexistence of migrants and residents in animal populations.
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Navinder J Singh
Full Text Available Partial migration, whereby a proportion of the population migrates, is common across the animal kingdom. Much of the focus in the literature has been on trying to explain the underlying mechanisms for the coexistence of migrants and residents. In addition, there has been an increasing number of reports on the prevalence and frequency of partially migratory populations. One possible explanation for the occurrence of partial migration, which has received no attention in the literature, is that of 'transient coexistence' during the invasion phase of a superior behaviour. In this study we develop a theoretical basis for explaining partial migration as a transient coexistence and derive a method to predict the frequency of residents and migrants in partially migrating populations. This method is useful to predict the frequencies of migrants and residents in a small set of populations as a complementing hypothesis to 'an Evolutionary Stable Strategy (ESS'. We use the logistic growth equation to derive a formula for predicting the frequencies of residents and migrants. We also use simulations and empirical data from white perch (Morone americana, moose (Alces alces and red deer (Cervus elaphus to demonstrate our approach. We show that the probability of detecting partial migration due to transient coexistence depends upon a minimum number of tracked or marked individuals for a given number of populations. Our approach provides a starting point in searching for explanations to the observed frequencies, by contrasting the observed pattern with both the predicted transient and the uniform random pattern. Aggregating such information on observed patterns (proportions of migrants and residents may eventually lead to the development of a quantitative theory for the equilibrium (ESS populations as well.
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Application of Human-Autonomy Teaming (HAT) Patterns to Reduce Crew Operations (RCO)
Shively, R. Jay; Brandt, Summer L.; Lachter, Joel; Matessa, Mike; Sadler, Garrett; Battiste, Henri
2016-01-01
Unmanned aerial systems, robotics, advanced cockpits, and air traffic management are all examples of domains that are seeing dramatic increases in automation. While automation may take on some tasks previously performed by humans, humans will still be required, for the foreseeable future, to remain in the system. The collaboration with humans and these increasingly autonomous systems will begin to resemble cooperation between teammates, rather than simple task allocation. It is critical to understand this human-autonomy teaming (HAT) to optimize these systems in the future. One methodology to understand HAT is by identifying recurring patterns of HAT that have similar characteristics and solutions. This paper applies a methodology for identifying HAT patterns to an advanced cockpit project.
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Engendering climate change-induced migration
Caretta, Martina Angela; Miletto, Michela
2017-04-01
Climate change leads to increased climate variability, which is manifest in extreme weather events such as floods and droughts. These put at stake agricultural productivity, forestry, inland fisheries, aquaculture, water supply and sanitation which in turn hamper poorest householdś self-sufficiency and capability to cope with risks. Due to the risk of losing or the actual loss of livelihood, farmers in the Global South must look for alternative strategies to diversify risk. Migration is one of those strategies, which that can be seen either as an adaptive measure or an indicator of limits to adaptation to environmental stress. 60% of young migrants live in the Global South (UN, 2013). Many internally displaced people in the world are under the age of 18, some move with their families, other, mostly in South Asia and West Africa, migrate alone. Youth, as all migrants, are seeking better economic opportunities to support themselves and their families. Migration is a gendered process which plays out differently in diverse societies depending on local cultural norms that do not only affect and are affected by gender roles, but also by age, class and ethnicity. Threats to water availability, access and water hazards have diverse impacts on men and women. The link gender and climate-induced migration is still under investigation and few studies provide concrete country specific examples of this phenomenon. Our paper will present a state of the art literature review around climate-induced migration in the Global South from a gender perspective showing how meńs and womeńs migratory decisions, patterns and outcomes differ at the stage pre-during post migration.
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People's Republic of China's Contemporary Migration Processes
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Martina Bofulin
2014-12-01
Full Text Available The last three decades of significant political, economic and social transformations in the People’s Republic of China have had a profound impact on the Chinese society. The article addresses selected topics of Chinese migration that give a more nuanced understanding of migration processes and their contextualization within the contemporary Chinese society: the internal migration, emigration from China and international immigration to China. Migration from rural area towards urban eastern coast is one of the largest spatial movements in the human history, as well as a key component of the economic rise and subsequent social change. Emigration from China has, despite its relatively small volume, profoundly transformed local places of origin, a process that is not independent from the current international geopolitical situation. Immigration of international migrants to China is a relatively new phenomenon that puts the country on the map of migration destination countries for the first time in sixty years. The author concludes that the prevalent research perspectives on Chinese migration offer only a limited insight and suggests some possible alternative ways of analyzing this phenomenon.
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Spatial and temporal patterns of human Puumala virus (PUUV infections in Germany
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Sarah Cunze
2018-02-01
Full Text Available Background Worldwide, the number of recorded human hantavirus infections as well as the number of affected countries is on the rise. In Europe, most human hantavirus infections are caused by the Puumala virus (PUUV, with bank voles (Myodes glareolus as reservoir hosts. Generally, infection outbreaks have been related to environmental conditions, particularly climatic conditions, food supply for the reservoir species and land use. However, although attempts have been made, the insufficient availability of environmental data is often hampering accurate temporal and spatially explicit models of human hantavirus infections. Methods In the present study, dynamics of human PUUV infections between 2001 and 2015 were explored using ArcGIS in order to identify spatio-temporal patterns. Results Percentage cover of forest area was identified as an important factor for the spatial pattern, whereas beech mast was found explaining temporal patterns of human PUUV infections in Germany. High numbers of infections were recorded in 2007, 2010 and 2012 and areas with highest records were located in Baden-Wuerttemberg (southwest Germany and North Rhine-Westphalia (western Germany. Conclusion More reliable data on reservoir host distribution, pathogen verification as well as an increased awareness of physicians are some of the factors that should improve future human infection risk assessments in Germany.
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The effect of migration on family structures in sub-Saharan Africa.
Okoth-ogendo, H W
1989-06-01
This paper assesses the effect of migration or family structures in sub-Saharan Africa, especially the effect of emigration on the reproduction, production, and social stability of the family in areas of origin in the predominantly agrarian communities of East and Southern Africa. Migration in precolonial Africa usually occurred for 1 of the following reasons: 1) the search by communities for new habitats and opportunities; 2) as a community response to droughts, floods, environmental degradation, and similar disasters; and 3) as a result of internecine wars, civil strife, and general hostilities. Thus, because of the collective nature of early migrations, the family unit maintained a much greater degree of social cohesion. The effects of the rise of the modern state in Africa on migration include 1) spatial limits of collective migration were frozen, 2) the colonial boundaries did not always correspond to cultural divisions, 3) both migration within colonial boundaries and individual migration became dominant, and 4) cyclical migration began. The end of colonialism resulted in 1) difficulties in creating strong and internally coherent nation states because of the uncertainty of national borders and 2) more cyclical migrants. The effects of migration on reproduction in the family during the colonial period include 17 extremely low fertility rates, 2) widespread domestic instability, and 3) exacerbation of moral decadence. Contemporary patterns of emigration have been far less disruptive, due in part to increased personal mobility and migration of the complete reproductive unit. The effects of migration on production include 1) depletion of labor for production; 2) women had to assume production functions, together with all their other responsibilities; and 3) very little cash or goods were available for remittance to areas of origin. Production and productivity among rural African families will continue to suffer as long as plantations, mines, and urban centers
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Who's afraid of Patterns?: The Particular versus the Universal and the Meaning of Humanities 3.0
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Rens Bod
2013-12-01
Full Text Available The advent of Digital Humanities has enabled scholars to identify previously unknown patterns in the arts and letters; but the notion of pattern has also been subject to debate. In my response to the authors of this Forum, I argue that ‘pattern’ should not be confused with universal pattern. The term pattern itself is neutral with respect to being either particular or universal. Yet the testing and discovery of patterns – be they local or global – is greatly aided by digital tools. While such tools have been beneficial for the humanities, numerous scholars lack a sufficient grasp of the underlying assumptions and methods of these tools. I argue that in order to criticise and interpret the results of digital humanities properly, scholars must acquire a good working knowledge of the underlying tools and methods. Only then can digital humanities be fully integrated (humanities 3.0 with time-honoured (humanities 1.0 tools of hermeneutics and criticism.
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Monteith, Kevin L.; Bleich, Vernon C.; Stephenson, Thomas R.; Pierce, Beck M.; Conner, Mary M.; Klaver, Robert W.; Bowyer, R. Terry
2011-01-01
Phenological events of plants and animals are sensitive to climatic processes. Migration is a life-history event exhibited by most large herbivores living in seasonal environments, and is thought to occur in response to dynamics of forage and weather. Decisions regarding when to migrate, however, may be affected by differences in life-history characteristics of individuals. Long-term and intensive study of a population of mule deer (Odocoileus hemionus) in the Sierra Nevada, California, USA, allowed us to document patterns of migration during 11 years that encompassed a wide array of environmental conditions. We used two new techniques to properly account for interval-censored data and disentangle effects of broad-scale climate, local weather patterns, and plant phenology on seasonal patterns of migration, while incorporating effects of individual life-history characteristics. Timing of autumn migration varied substantially among individual deer, but was associated with the severity of winter weather, and in particular, snow depth and cold temperatures. Migratory responses to winter weather, however, were affected by age, nutritional condition, and summer residency of individual females. Old females and those in good nutritional condition risked encountering severe weather by delaying autumn migration, and were thus risk-prone with respect to the potential loss of foraging opportunities in deep snow compared with young females and those in poor nutritional condition. Females that summered on the west side of the crest of the Sierra Nevada delayed autumn migration relative to east-side females, which supports the influence of the local environment on timing of migration. In contrast, timing of spring migration was unrelated to individual life-history characteristics, was nearly twice as synchronous as autumn migration, differed among years, was related to the southern oscillation index, and was influenced by absolute snow depth and advancing phenology of plants
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Migration of the Duraloc cup after 5 years.
Stihsen, Christoph; Pabinger, Christof; Radl, Roman; Rehak, Peter; Windhager, Reinhard
2008-12-01
The Duraloc cup is a frequently used metal-backed, porous-coated, hemispherical, press-fit acetabular component. Published data on loosening rates are contradictory. In this study we investigated migration patterns with computer-assisted Einzel-Bild-Roentgen-Analyse (EBRA) of 67 Duraloc 100 cups. Cup migration and clinical scores were analysed over a 5-year follow-up period. Median total migration of the Duraloc 100 cup was 1.21 mm at 5 years. Seventy-five percent of implants were radiologically stable at 2 years and 90% at 4 years. One cup loosened aseptically at 60 months, requiring revision. Cup diameters > or = 54 mm migrated significantly more than cups < 54 mm in diameter (p = 0.029 at 4 years). There was a significant correlation between high polyethylene wear and further migrating cups within the first post-operative year (p = 0.035 at 12 months). Our analysis revealed significantly higher wear in males (p = 0.029 at 4 years). Radiological loosening at two years could be calculated using receiver-operating characteristic curve analysis, and 1.2 mm as an adequate threshold value (sensitivity = 100%, specificity = 89%).
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Sehrawat Jagmahender Singh
2017-09-01
Full Text Available This article reviews the present scenario of use of stable isotopes (mainly δ13C, δ15N, δ18O, 87Sr to trace past life behaviours like breast feeding and weaning practices, the geographic origin, migration history, paleodiet and subsistence patterns of past populations from the chemical signatures of isotopes imprinted in human skeletal remains. This approach is based on the state that food-web isotopic signatures are seen in the human bones and teeth and such signatures can change parallely with a variety of biogeochemical processes. By measuring δ13C and δ15N isotopic values of subadult tissues of different ages, the level of breast milk ingestion at particular ages and the components of the complementary foods can be assessed. Strontium and oxygen isotopic analyses have been used for determining the geographic origins and reconstructing the way of life of past populations as these isotopes can map the isotopic outline of the area from where the person acquired water and food during initial lifetime. The isotopic values of strontium and oxygen values are considered specific to geographical areas and serve as reliable chemical signatures of migration history of past human populations (local or non-local to the site. Previous isotopic studies show that the subsistence patterns of the past human populations underwent extensive changes from nomadic to complete agricultural dependence strategies. The carbon and nitrogen isotopic values of local fauna of any archaeological site can be used to elucidate the prominence of freshwater resources in the diet of the past human populations found near the site. More extensive research covering isotopic descriptions of various prehistoric, historic and modern populations is needed to explore the role of stable isotope analysis for provenancing human skeletal remains and assessing human migration patterns/routes, geographic origins, paleodiet and subsistence practices of past populations.
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Genome-wide patterns of nucleotide polymorphism in domesticated rice
DEFF Research Database (Denmark)
Caicedo, Ana L; Williamson, Scott H; Hernandez, Ryan D
2007-01-01
Domesticated Asian rice (Oryza sativa) is one of the oldest domesticated crop species in the world, having fed more people than any other plant in human history. We report the patterns of DNA sequence variation in rice and its wild ancestor, O. rufipogon, across 111 randomly chosen gene fragments......, and use these to infer the evolutionary dynamics that led to the origins of rice. There is a genome-wide excess of high-frequency derived single nucleotide polymorphisms (SNPs) in O. sativa varieties, a pattern that has not been reported for other crop species. We developed several alternative models...... to explain contemporary patterns of polymorphisms in rice, including a (i) selectively neutral population bottleneck model, (ii) bottleneck plus migration model, (iii) multiple selective sweeps model, and (iv) bottleneck plus selective sweeps model. We find that a simple bottleneck model, which has been...
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Evolution of mammalian migrations for refuge, breeding, and food.
Gnanadesikan, Gitanjali E; Pearse, William D; Shaw, Allison K
2017-08-01
Many organisms migrate between distinct habitats, exploiting variable resources while profoundly affecting ecosystem services, disease spread, and human welfare. However, the very characteristics that make migration captivating and significant also make it difficult to study, and we lack a comprehensive understanding of which species migrate and why. Here we show that, among mammals, migration is concentrated within Cetacea and Artiodactyla but also diffusely spread throughout the class (found in 12 of 27 orders). We synthesize the many ecological drivers of round-trip migration into three types of movement-between breeding and foraging sites, between breeding and refuge sites, and continuous tracking of forage/prey-each associated with different traits (body mass, diet, locomotion, and conservation status). Our results provide only partial support for the hypothesis that migration occurs without phylogenetic constraint. Furthermore, our findings suggest that categorizing migration into these three types may aid predictions of migrants' responses to environmental changes.
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Outward migration may alter population dynamics and income inequality
Shayegh, Soheil
2017-11-01
Climate change impacts may drive affected populations to migrate. However, migration decisions in response to climate change could have broader effects on population dynamics in affected regions. Here, I model the effect of climate change on fertility rates, income inequality, and human capital accumulation in developing countries, focusing on the instrumental role of migration as a key adaptation mechanism. In particular, I investigate how climate-induced migration in developing countries will affect those who do not migrate. I find that holding all else constant, climate change raises the return on acquiring skills, because skilled individuals have greater migration opportunities than unskilled individuals. In response to this change in incentives, parents may choose to invest more in education and have fewer children. This may ultimately reduce local income inequality, partially offsetting some of the damages of climate change for low-income individuals who do not migrate.
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Assessment of human respiration patterns via noncontact sensing using Doppler multi-radar system.
Gu, Changzhan; Li, Changzhi
2015-03-16
Human respiratory patterns at chest and abdomen are associated with both physical and emotional states. Accurate measurement of the respiratory patterns provides an approach to assess and analyze the physical and emotional states of the subject persons. Not many research efforts have been made to wirelessly assess different respiration patterns, largely due to the inaccuracy of the conventional continuous-wave radar sensor to track the original signal pattern of slow respiratory movements. This paper presents the accurate assessment of different respiratory patterns based on noncontact Doppler radar sensing. This paper evaluates the feasibility of accurately monitoring different human respiration patterns via noncontact radar sensing. A 2.4 GHz DC coupled multi-radar system was used for accurate measurement of the complete respiration patterns without any signal distortion. Experiments were carried out in the lab environment to measure the different respiration patterns when the subject person performed natural breathing, chest breathing and diaphragmatic breathing. The experimental results showed that accurate assessment of different respiration patterns is feasible using the proposed noncontact radar sensing technique.
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Migration: a concept analysis from a nursing perspective.
Freeman, Michelle; Baumann, Andrea; Blythe, Jennifer; Fisher, Anita; Akhtar-Danesh, Noori
2012-05-01
This article is a report of a concept analysis of nurse migration. International migration is increasing and nurse migrants are active participants in this movement. Migration is a complex term and can be examined from a range of perspectives. Analysis of nurse migration is needed to guide policy, practice and research. A literature search was undertaken using electronic literature indexes, specific journals and websites, internet search engines and hand searches. No timeframe was placed on the search. Most literature found was published between 2001 and 2009. A sample of 80 documents met the inclusion criteria. Walker and Avant's approach guided the analysis. Nurse migration can be defined by five attributes: the motivation and decisions of individuals; external barriers and facilitators; freedom of choice to migrate; freedom to migrate as a human right, and dynamic movement. Antecedents of migration include the political, social, economic, legal, historical and educational forces that comprise the push and pull framework. The consequences of migration are positive or negative depending on the viewpoint and its affect on the individual and other stakeholders such as the source country, destination country, healthcare systems and the nursing profession. This concept analysis clarified the complexities surrounding nurse migration. A nursing-specific middle-range theory was proposed to guide the understanding and study of nurse migration. © 2011 Blackwell Publishing Ltd.
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Directory of Open Access Journals (Sweden)
Said Yekta Sareh
2011-02-01
Full Text Available Abstract Background Bisphosphonates are therapeutics of bone diseases, such as Paget's disease, multiple myeloma or osteoclastic metastases. As a severe side effect the bisphosphonate induced osteonecrosis of the jaw (BONJ often requires surgical treatment and is accompanied with a disturbed wound healing. Therefore, the influence on adhesion and migration of human osteoblasts (hOB after bisphosphonate therapy has been investigated by morphologic as well as gene expression methods. Methods By a scratch wound experiment, which measures the reduction of defined cell layer gap, the morphology and migration ability of hOB was evaluated. A test group of hOB, which was stimulated by zoledronate 5 × 10-5M, and a control group of unstimulated hOB were applied. Furthermore the gene expression of integrin aVb3 and tenascin C was quantified by Real-Time rtPCR at 5data points over an experimental period of 14 days. The bisphosphonates zoledronate, ibandronate and clodronate have been compared with an unstimulated hOB control. Results After initially identical migration and adhesion characteristics, zoledronate inhibited hOB migration after 50 h of stimulation. The integrinavb3 and tenascin C gene expression was effected by bisphosphonates in a cell line dependent manner with decreased, respectively inconsistent gene expression levels over time. The non-nitrogen containing bisphosphonates clodronate led to decreased gene expression levels. Conclusion Bisphosphonates seem to inhibit hOB adhesion and migration. The integrin aVb3 and tenascin C gene expression seem to be dependent on the cell line. BONJ could be enhanced by an inhibition of osteoblast adhesion and migration. The gene expression results, however, suggest a cell line dependent effect of bisphosphonates, which could explain the interindividual differences of BONJ incidences.
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Liu, Ze-Hua; Yin, Hua; Dang, Zhi
2017-01-01
With the widespread application of plastic pipes in drinking water distribution system, the effects of various leachable organic chemicals have been investigated and their occurrence in drinking water supplies is monitored. Most studies focus on the odor problems these substances may cause. This study investigates the potential endocrine disrupting effects of the migrating compound 2,4-di-tert-butylphenol (2,4-d-t-BP). The summarized results show that the migration of 2,4-d-t-BP from plastic pipes could result in chronic exposure and the migration levels varied greatly among different plastic pipe materials and manufacturing brands. Based on estrogen equivalent (EEQ), the migrating levels of the leachable compound 2,4-d-t-BP in most plastic pipes were relative low. However, the EEQ levels in drinking water migrating from four out of 15 pipes may pose significant adverse effects. With the increasingly strict requirements on regulation of drinking water quality, these results indicate that some drinking water transported with plastic pipes may not be safe for human consumption due to the occurrence of 2,4-d-t-BP. Moreover, 2,4-d-t-BP is not the only plastic pipe-migrating estrogenic compound, other compounds such as 2-tert-butylphenol (2-t-BP), 4-tert-butylphenol (4-t-BP), and others may also be leachable from plastic pipes.
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Fenske, Robert H.; Scott, Craig S.
This study of student migration patterns is based on the assumption that an important determinant of change in student migration patterns in recent years has been the increase in the number of two-year colleges. The present study utilizes data which makes possible an analysis of the relationship between student characteristics and their migration…
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Modeling Bird Migration under Climate Change: A Mechanistic Approach
Smith, James A.
2009-01-01
How will migrating birds respond to changes in the environment under climate change? What are the implications for migratory success under the various accelerated climate change scenarios as forecast by the Intergovernmental Panel on Climate Change? How will reductions or increased variability in the number or quality of wetland stop-over sites affect migratory bird species? The answers to these questions have important ramifications for conservation biology and wildlife management. Here, we describe the use of continental scale simulation modeling to explore how spatio-temporal changes along migratory flyways affect en-route migration success. We use an individually based, biophysical, mechanistic, bird migration model to simulate the movement of shorebirds in North America as a tool to study how such factors as drought and wetland loss may impact migratory success and modify migration patterns. Our model is driven by remote sensing and climate data and incorporates important landscape variables. The energy budget components of the model include resting, foraging, and flight, but presently predation is ignored. Results/Conclusions We illustrate our model by studying the spring migration of sandpipers through the Great Plains to their Arctic breeding grounds. Why many species of shorebirds have shown significant declines remains a puzzle. Shorebirds are sensitive to stop-over quality and spacing because of their need for frequent refueling stops and their opportunistic feeding patterns. We predict bird "hydrographs that is, stop-over frequency with latitude, that are in agreement with the literature. Mean stop-over durations predicted from our model for nominal cases also are consistent with the limited, but available data. For the shorebird species simulated, our model predicts that shorebirds exhibit significant plasticity and are able to shift their migration patterns in response to changing drought conditions. However, the question remains as to whether this
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Selective Modulation of Integrin-mediated Cell Migration by Distinct ADAM Family MembersV⃞
Huang, Jing; Bridges, Lance C.; White, Judith M.
2005-01-01
A disintegrin and a metalloprotease (ADAM) family members have been implicated in many biological processes. Although it is recognized that recombinant ADAM disintegrin domains can interact with integrins, little is known about ADAM-integrin interactions in cellular context. Here, we tested whether ADAMs can selectively regulate integrin-mediated cell migration. ADAMs were expressed in Chinese hamster ovary cells that express defined integrins (α4β1, α5β1, or both), and cell migration on full-length fibronectin or on its α4β1 or α5β1 binding fragments was studied. We found that ADAMs inhibit integrin-mediated cell migration in patterns dictated by the integrin binding profiles of their isolated disintegrin domains. ADAM12 inhibited cell migration mediated by the α4β1 but not the α5β1 integrin. ADAM17 had the reciprocal effect; it inhibited α5β1- but not α4β1-mediated cell migration. ADAM19 and ADAM33 inhibited migration mediated by both α4β1 and α5β1 integrins. A point mutation in the ADAM12 disintegrin loop partially reduced the inhibitory effect of ADAM12 on cell migration on the α4β1 binding fragment of fibronectin, whereas mutations that block metalloprotease activity had no effect. Our results indicate that distinct ADAMs can modulate cell migration mediated by specific integrins in a pattern dictated, at least in part, by their disintegrin domains. PMID:16079176
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Luanda-Holanda; irregular migration from Angola to the Netherlands
van Wijk, J.
2008-01-01
Against the backdrop of push-pull and social network theories on migration and criminological theory on human smuggling, this article tries to answer the questions of why and how Angolan asylum-seekers migrated to the Netherlands since the end of the 1990s. The study shows that the migrants can be
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Directory of Open Access Journals (Sweden)
Megan Moore
Full Text Available Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity.The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts.This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.