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Sample records for honduras population dynamics

  1. Honduras.

    Science.gov (United States)

    1989-09-01

    Honduras is a country with an area of 68,000 square miles, with considerable mountainous terrain, and a subtropical but variable climate. It has a population of 4.4 million people and an annual growth rate of 3.1%. The ethnic make up is 90% mestizo, a mixture of Indian and European, with others consisting of Arab, African, oriental, and Indians. The main religion is Catholic with a fast growing Protestant minority, and the language is Spanish. Infant mortality is 60/1000 and life expectancy is 63 years. The work force is mainly agricultural 63%, services 20%, manufacturing 9%, and construction 3%. The government is a democratic constitutional republic established in 1821. The budget is $1,334 million with 7% used for defense, and the gross national product is $4.4 billion with an annual growth rate of 4.5%. Despite being poor and underdeveloped, natural resources include arable land, hydro- electric power, and considerable forest, marine, and mineral resources. Agriculture products include coffee, bananas, citrus fruit, corn, beans, and livestock. The major industries are textiles, cement, wood products, cigars and foodstuffs. Unemployment is over 15% and underemployment is estimated over 40% with the literacy rate at only 60%. In the last few years with US aid the economy has grown 3.8% a year assisted by mining, construction and the service sectors. Honduras must undertake major economic reforms to gain longterm growth and stability since it has large fiscal and trade deficits, a large public bureaucracy, poorly run state enterprises and overvalued exchange rate.

  2. Honduras.

    Science.gov (United States)

    1992-05-01

    Honduras has an area of 112,088 square km or 43,277 square miles with a population of 4.8 million in 1991 of whom 90% are mestizos. Literacy is 68%, the infant mortality rate is 60/1000, and life expectancy is 63 years. After independence from Spain in 1821 the Central American Federation collapsed in 1938. There have been 300 internal rebellions since independence. With an inadequate economic infrastructure, sociopolitical integration has been fragile. In 1982 the Suazo government relied on US support to face the economic recession, the threat posed by the Marxist government in Nicaragua, and civil war in El Salvador. USAID sponsored ambitious social and economic projects. A peaceful transfer of power between civilian presidents occurred in 1986 despite an electoral quirk. In 1990 President Callejas introduced reforms to reduce the deficit, and to stimulate investments and exports. After initial higher inflation and low growth in 1990 and 1991, modest progress is forecast for 1992 and 1993. The powerful military has been kept in check, and human rights have been better protected. The country is among the poorest in Latin America with underemployment of 30-40% and a mostly agricultural economy. The 1990 reforms of deregulation of prices, liberalization of trade, less protectionism, and export orientation is expected to produce longterm benefits not only in agriculture but also in manufacturing. The US is the primary trading partner, and the main direct foreign investor (fruits, refining, and mining). The slash-and-burn agricultural cultivation has created environmental destruction, and as a sign of public awareness the armed forces have engaged in reforestation and fighting forest fires.

  3. Surnames in Honduras: A study of the population of Honduras through isonymy.

    Science.gov (United States)

    Herrera Paz, Edwin Francisco; Scapoli, Chiara; Mamolini, Elisabetta; Sandri, Massimo; Carrieri, Alberto; Rodriguez-Larralde, Alvaro; Barrai, Italo

    2014-05-01

    In this work, we investigated surname distribution in 4,348,021 Honduran electors with the aim of detecting population structure through the study of isonymy in three administrative levels: the whole nation, the 18 departments, and the 298 municipalities. For each administrative level, we studied the surname effective number, α, the total inbreeding, FIT , the random inbreeding, FST , and the local inbreeding, FIS . Principal components analysis, multidimensional scaling, and cluster analysis were performed on Lasker's distance matrix to detect the direction of surname diffusion and for a graphic representation of the surname relationship between different locations. The values of FIT , FST , and FIS display a variation of random inbreeding between the administrative levels in the Honduras population, which is attributed to the "Prefecture effect." Multivariate analyses of department data identified two main clusters, one south-western and the second north-eastern, with the Bay Islands and the eastern Gracias a Dios out of the main clusters. The results suggest that currently the population structure of this country is the result of the joint action of short-range directional migration and drift, with drift dominating over migration, and that population diffusion may have taken place mainly in the NW-SE direction. © 2014 John Wiley & Sons Ltd/University College London.

  4. Genetic structure of Plasmodium falciparum populations across the Honduras-Nicaragua border.

    Science.gov (United States)

    Larrañaga, Nerea; Mejía, Rosa E; Hormaza, José I; Montoya, Alberto; Soto, Aida; Fontecha, Gustavo A

    2013-10-04

    The Caribbean coast of Central America remains an area of malaria transmission caused by Plasmodium falciparum despite the fact that morbidity has been reduced in recent years. Parasite populations in that region show interesting characteristics such as chloroquine susceptibility and low mortality rates. Genetic structure and diversity of P. falciparum populations in the Honduras-Nicaragua border were analysed in this study. Seven neutral microsatellite loci were analysed in 110 P. falciparum isolates from endemic areas of Honduras (n = 77) and Nicaragua (n = 33), mostly from the border region called the Moskitia. Several analyses concerning the genetic diversity, linkage disequilibrium, population structure, molecular variance, and haplotype clustering were conducted. There was a low level of genetic diversity in P. falciparum populations from Honduras and Nicaragua. Expected heterozigosity (H(e)) results were similarly low for both populations. A moderate differentiation was revealed by the F(ST) index between both populations, and two putative clusters were defined through a structure analysis. The main cluster grouped most of samples from Honduras and Nicaragua, while the second cluster was smaller and included all the samples from the Siuna community in Nicaragua. This result could partially explain the stronger linkage disequilibrium (LD) in the parasite population from that country. These findings are congruent with the decreasing rates of malaria endemicity in Central America.

  5. Population data for 12 Y-chromosome STR loci in a sample from Honduras.

    Science.gov (United States)

    Matamoros, Mireya; Yurrebaso, Iñaki; Gusmão, Leonor; García, Oscar

    2009-09-01

    Haplotype, allele frequencies and population data of 12 Y-chromosome STR loci DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438 and DYS439 were determined from a sample of 128 unrelated male individuals from Honduras, Central America. A total of 112 haplotypes were identified by the 12 Y-STR loci of which 98 were unique. The haplotype diversity (98.99%) and the proportion of different haplotypes (87.50%) were estimated. Genetic distances were calculated between Honduras and other populations from Southern and Central America, Europe and Africa. The analysis of a Multi Dimensional Scaling (MDS) plot, based on pairwise R(ST) genetic distances, allowed to conclude that Honduras is highly differentiated from the African samples (0.343Honduras showed a lower genetic distance to the European cluster (composed by European and South American general population samples from Brazil, Argentina, Colombia and Venezuela) than to the Central American cluster (Mexico and El Salvador).

  6. Population, conservation, and land use change in Honduras

    Science.gov (United States)

    Max J. Pfeffer; John W. Schlelhas; Stephen D. DeGloria; Jorge Gomez

    2005-01-01

    This paper examines the role of population density on land use allocation and change. We are especially interested in the management of fallow areas that have come under increasing pressure given restrictions imposed by the creation of protected areas like national parks. It is argued that these restrictions to reduce deforestation create a relative scarcity of land,...

  7. Migration, Multiple Sexual Partnerships, and Sexual Concurrency in the Garífuna Population of Honduras.

    Science.gov (United States)

    Gandhi, Anisha D; Pettifor, Audrey; Barrington, Clare; Marshall, Stephen W; Behets, Frieda; Guardado, Maria Elena; Farach, Nasim; Ardón, Elvia; Paz-Bailey, Gabriela

    2015-09-01

    The Garífuna, an ethnic minority group in Honduras, have been disproportionately affected by HIV. Previous research suggests that migration and high rates of multiple sexual partnerships are major drivers of the epidemic. Using data from a 2012 population-based survey, we assessed whether temporary migration was associated with (1) multiple sexual partnerships and (2) sexual concurrency among Garífuna men and women in Honduras. Among both men and women, temporary migration in the last year was associated with an increased likelihood of multiple sexual partnerships and with concurrency, though only the association between migration and multiple sexual partnerships among men was statistically significant (Adjusted Prevalence Ratio 1.7, 95 % CI 1.2-2.4). Migration may contribute to HIV/STI vulnerability among Garífuna men and women via increases in these sexual risk behaviors. Research conducted among men and women at elevated risk of HIV should continue to incorporate measures of mobility, including history of internal migration.

  8. Population dynamics

    Directory of Open Access Journals (Sweden)

    Cooch, E. G.

    2004-06-01

    Full Text Available Increases or decreases in the size of populations over space and time are, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change over time in the abundance of some population is the simple difference between the number of additions (individuals entering the population minus the number of subtractions (individuals leaving the population. Of course, the precise nature of the pattern and process of these additions and subtractions is often complex, and population biology is often replete with fairly dense mathematical representations of both processes. While there is no doubt that analysis of such abstract descriptions of populations has been of considerable value in advancing our, there has often existed a palpable discomfort when the ‘beautiful math’ is faced with the often ‘ugly realities’ of empirical data. In some cases, this attempted merger is abandoned altogether, because of the paucity of ‘good empirical data’ with which the theoretician can modify and evaluate more conceptually–based models. In some cases, the lack of ‘data’ is more accurately represented as a lack of robust estimates of one or more parameters. It is in this arena that methods developed to analyze multiple encounter data from individually marked organisms has seen perhaps the greatest advances. These methods have rapidly evolved to facilitate not only estimation of one or more vital rates, critical to population modeling and analysis, but also to allow for direct estimation of both the dynamics of populations (e.g., Pradel, 1996, and factors influencing those dynamics (e.g., Nichols et al., 2000. The interconnections between the various vital rates, their estimation, and incorporation into models, was the general subject of our plenary presentation by Hal Caswell (Caswell & Fujiwara, 2004. Caswell notes that although interest has traditionally

  9. Short communication: HIV incidence among vulnerable populations in Honduras: results from an integrated behavioral and biological survey among female sex workers, men who have sex with men, and Garifuna in Honduras, 2006.

    Science.gov (United States)

    Kim, Andrea A; Morales, Sonia; Lorenzana de Rivera, Ivette; Paredes, Mayte; Juarez, Sandra; Alvarez, Berta; Liu, Xin; Parekh, Bharat; Monterroso, Edgar; Paz-Bailey, Gabriela

    2013-03-01

    Honduras has one of the highest HIV prevalence rates in Central America. Data on HIV incidence are needed to identify groups at greatest need of prevention interventions to inform the national HIV response. We applied a test for recent infection to HIV-positive specimens from a biological and behavioral survey to estimate assay-derived incidence among men who have sex with men (MSM), female sex workers (FSW), and the Garifuna population in Honduras. Assay-derived estimates were compared to the mathematically modeled estimates in the same populations to assess plausibility of the assay-based estimates. Assay-derived incidence was 1.1% (95% CI 0.2-2.0) among MSM, 0.4% (95% CI 0.1-0.8) among the Garifuna, and 0% (95% CI 0-0.01) among FSWs. The modeled incidence estimates were similar at 1.03% among MSM, 0.30% among the Garifuna, and 0.23% among FSWs. HIV incidence based on the assay was highest among MSM in Honduras, lowest among FSWs, and similar to modeled incidence in these groups. Targeted programs on HIV prevention, care, and treatment are urgently needed for the MSM population. Continued support for existing prevention programs for FSWs and Garifuna are recommended.

  10. Population genetic data for 15 STR loci (Identifiler kit) in Honduras.

    Science.gov (United States)

    Matamoros, Mireya; Pinto, Yessica; Inda, Francisco Javier; García, Oscar

    2008-09-01

    Allele frequencies for 15 STR autosomal loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818 and FGA) were obtained from a sample of 198 unrelated individuals from Honduras, Central America.

  11. A Sustainable and Resilient Housing Model for Indigenous Populations of the Mosquitia Region (Honduras)

    OpenAIRE

    Gambino, Valeria; Micangeli, Andrea; Naso, Vincenzo; Michelangeli, Emanuele; Mario, Luca

    2014-01-01

    This study develops a sustainable housing model for the Mosquitia region of Honduras, aimed at improving the living conditions of indigenous communities and reducing their vulnerability to the effects of climate change. The improved housing efficiency and resilience will contribute to strengthen sanitation and hygiene, improve the living comfort and reduce environmental impact, particularly focusing on preserving the forest biodiversity. The project was developed following the criteria of env...

  12. A Sustainable and Resilient Housing Model for Indigenous Populations of the Mosquitia Region (Honduras

    Directory of Open Access Journals (Sweden)

    Valeria Gambino

    2014-08-01

    Full Text Available This study develops a sustainable housing model for the Mosquitia region of Honduras, aimed at improving the living conditions of indigenous communities and reducing their vulnerability to the effects of climate change. The improved housing efficiency and resilience will contribute to strengthen sanitation and hygiene, improve the living comfort and reduce environmental impact, particularly focusing on preserving the forest biodiversity. The project was developed following the criteria of environmental, technical, social and economic sustainability to propose a shared model, reproducible by the beneficiaries living in different kinds of Mosquitian ecosystems. Increased building efficiency is obtained through optimization of construction techniques and improvement of materials’ performances. The main material of the proposed dwelling is wood, coherently with the “Miskita” tradition; the increase of its durability, which is obtained by proper seasoning and protection from atmospheric agents and parasites, contributes to the optimization of the use of this natural resource and to reducing the impact on deforestation, which threatens forest biodiversity. The data collection campaign, conducted before developing the housing model design and which has aimed at obtaining information on technical and social aspects related to residences’ welfare and health conditions, has highlighted the great importance of improving the construction model. Despite the advance in sanitary conditions and the economic level, the data collection campaign revealed that even the most developed communities amongst those visited have been perpetrating substantial construction errors, which reduce the resilience of structures to extreme natural phenomena, such as tropical storms and hurricanes, which frequently affect the Mosquitia region. This unexpected discovery increased the importance of housing model design in order to correct these improper construction

  13. Physical and sexual violence, mental health indicators, and treatment seeking among street-based population groups in Tegucigalpa, Honduras.

    Science.gov (United States)

    Rio Navarro, Javier; Cohen, Julien; Rocillo Arechaga, Eva; Zuniga, Edgardo

    2012-05-01

    To establish the prevalence of exposure to physical and sexual violence, mental health symptoms, and medical treatment-seeking behavior among three street-based subpopulation groups in Tegucigalpa, Honduras, and to assess the association between sociodemographic group, mental health indicators, and exposure to violence. An anonymous, cross-sectional survey among randomly selected street-based adolescents, adults, and commercial sex workers (CSWs) was undertaken at the end of 2010 in Tegucigalpa. Médecins Sans Frontières (MSF) mapped places where the study population gathers. Stratified probability samples were drawn for all groups, using two-stage random sampling. Trained MSF staff administered on-site standardized face-to-face questionnaires. Self-reported exposure to severe physical violence in the previous year was 20.9% among street-based adolescents, 28.8% among adults, and 30.6% among CSWs. For the physical violence event self-defined as most severe, 50.0% of the adolescents, 81.4% of the adults, and 70.6% of the CSWs sought medical treatment. Their exposure to severe sexual violence was 8.6%, 28.8%, and 59.2%, respectively. After exposure to the self-defined most severe sexual violence event, 14.3% of adolescents, 31.9% of adults, and 29.1% of CSWs sought treatment. Common mental health and substance abuse symptoms were highly prevalent and strongly associated with exposure to physical (odds ratio 4.5, P < 0.0001) and sexual (odds ratio 3.7, P = 0.0001) violence. Exposure to physical and sexual violence reached extreme levels among street-based subpopulations. Treatment-seeking behavior, particularly after severe sexual violence, was limited. The association of mental health and substance abuse symptoms with exposure to violence could lead to further victimization. Medical and psychological treatments targeting these groups are needed and could help decrease their vulnerability.

  14. Honduras: Caribbean Coast

    Energy Technology Data Exchange (ETDEWEB)

    Harborne, Alastair R.; Afzal, Daniel C.; Andrews, Mark J. [Coral Cay Conservation, London (United Kingdom)

    2001-07-01

    The coast of Honduras, Central America, represents the southern end of the Mesoamerican Barrier Reef System, although its marine resources are less extensive and studied than nearby Belize and Mexico. However, the coastal zone contains mainland reef formations, mangroves, wetlands, seagrass beds and extensive fringing reefs around its offshore islands, and has a key role in the economy of the country. Like most tropical areas, this complex of benthic habitats experiences limited annual variation in climatic and oceanographic conditions but seasonal and occasional conditions, particularly coral bleaching and hurricanes, are important influences. The effects of stochastic factors on the country's coral reefs were clearly demonstrated during 1998 when Honduras experienced a major hurricane and bleaching event. Any natural or anthropogenic impacts on reef health will inevitably affect other countries in Latin America, and vice versa, since the marine resources are linked via currents and the functioning of the system transcends political boundaries. Much further work on, for example, movement of larvae and transfer of pollutants is required to delineate the full extent of these links. Anthropogenic impacts, largely driven by the increasing population and proportion of people living in coastal areas, are numerous and include key factors such as agricultural run-off, over-fishing, urban and industrial pollution (particularly sewage) and infrastructure development. Many of these threats act synergistically and, for example, poor watershed management via shifting cultivation, increases sedimentation and pesticide run-off onto coral reefs, which increases stress to corals already affected by decreasing water quality and coral bleaching. Threats from agriculture and fishing are particularly significant because of the size of both industries. The desire to generate urgently required revenue within Honduras has also led to increased tourism which provides an over

  15. Honduras: Caribbean Coast.

    Science.gov (United States)

    Harborne, A R; Afzal, D C; Andrews, M J

    2001-12-01

    The coast of Honduras, Central America, represents the southern end of the Mesoamerican Barrier Reef System, although its marine resources are less extensive and studied than nearby Belize and Mexico. However, the coastal zone contains mainland reef formations, mangroves, wetlands, seagrass beds and extensive fringing reefs around its offshore islands, and has a key role in the economy of the country. Like most tropical areas, this complex of benthic habitats experiences limited annual variation in climatic and oceanographic conditions but seasonal and occasional conditions, particularly coral bleaching and hurricanes, are important influences. The effects of stochastic factors on the country's coral reefs were clearly demonstrated during 1998 when Honduras experienced a major hurricane and bleaching event. Any natural or anthropogenic impacts on reef health will inevitably affect other countries in Latin America, and vice versa, since the marine resources are linked via currents and the functioning of the system transcends political boundaries. Much further work on, for example, movement of larvae and transfer of pollutants is required to delineate the full extent of these links. Anthropogenic impacts, largely driven by the increasing population and proportion of people living in coastal areas, are numerous and include key factors such as agricultural run-off, over-fishing, urban and industrial pollution (particularly sewage) and infrastructure development. Many of these threats act synergistically and, for example, poor watershed management via shifting cultivation, increases sedimentation and pesticide run-off onto coral reefs, which increases stress to corals already affected by decreasing water quality and coral bleaching. Threats from agriculture and fishing are particularly significant because of the size of both industries. The desire to generate urgently required revenue within Honduras has also led to increased tourism which provides an overarching stress

  16. Market Squid Population Dynamics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains population dynamics data on paralarvae, juvenile and adult market squid collected off California and the US Pacific Northwest. These data were...

  17. Fish population dynamics

    National Research Council Canada - National Science Library

    Gulland, J. A

    1977-01-01

    This book describes how the dynamics of fish populations can be analysed in terms of the factors affecting their rates of growth, mortality and reproduction, with particular emphasis on the effects of fishing...

  18. Alternative Education Programmes and Middle School Dropout in Honduras

    Science.gov (United States)

    Marshall, Jeffery H.; Aguilar, Claudia R.; Alas, Mario; Castellanos, Renán Rápalo; Castro, Levi; Enamorado, Ramón; Fonseca, Esther

    2014-01-01

    Honduras has made steady progress in expanding post-primary school coverage in recent years, but many rural communities still do not provide a middle (lower secondary) school. As a result, Honduras has implemented a number of middle school alternative programmes designed to meet the needs of at-risk populations throughout the country. This article…

  19. El IDRC en Honduras

    International Development Research Centre (IDRC) Digital Library (Canada)

    Una investigación realizada por la Red de Desarrollo ... enfrentar la violencia juvenil. □ los residentes urbanos ... recientes inversiones y la presencia de conductas anticompetitivas ... Foro Social de Deuda Externa y Desarrollo de Honduras.

  20. Divergence in morphology, but not habitat use, despite low genetic differentiation among insular populations of the lizard Anolis lemurinus in Honduras

    Science.gov (United States)

    Logan, M.L.; Montgomery, Chad E.; Boback, Scott M.; Reed, R.N.; Campbell, J.A.

    2012-01-01

    Studies of recently isolated populations are useful because observed differences can often be attributed to current environmental variation. Two populations of the lizard Anolis lemurinus have been isolated on the islands of Cayo Menor and Cayo Mayor in the Cayos Cochinos Archipelago of Honduras for less than 15 000 y. We measured 12 morphometric and 10 habitat-use variables on 220 lizards across these islands in 2 y, 2008 and 2009. The goals of our study were (1) to explore patterns of sexual dimorphism, and (2) to test the hypothesis that differences in environment among islands may have driven divergence in morphology and habitat use despite genetic homogeneity among populations. Although we found no differences among sexes in habitat use, males had narrower pelvic girdles and longer toe pads on both islands. Between islands, males differed in morphology, but neither males nor females differed in habitat use. Our data suggest that either recent selection has operated differentially on males despite low genetic dill'erentiation, or that they display phenotypic plasticity in response to environmental variation. We suggest that patterns may be driven by variation in intrapopulation density or differences in predator diversity among islands.

  1. Africa population dynamics

    OpenAIRE

    Akinyoade, A.; Damen, J.C.M.; Dietz, A.J.; Kilama, B.B.; Omme, van, G.

    2014-01-01

    Africa's population has grown extremely rapidly over the last fifty years from 289 million inhabitants in 1961 to more than 1 billion today. This is a growth rate of 350% in just half a century and the number of urban residents has increased even more quickly: from 65 million in 1960 to 460 million today, or from 20% to 46% of the population as a whole. Demographers predict that soon more than 50% of all Africans will be living in cities. The average life expectancy, literacy rates and primar...

  2. Africa population dynamics

    NARCIS (Netherlands)

    Akinyoade, A.; Damen, J.C.M.; Dietz, A.J.; Kilama, B.B.; Omme, van G.

    2014-01-01

    Africa's population has grown extremely rapidly over the last fifty years from 289 million inhabitants in 1961 to more than 1 billion today. This is a growth rate of 350% in just half a century and the number of urban residents has increased even more quickly: from 65 million in 1960 to 460 million

  3. Legal framework: Renewables in Honduras

    International Nuclear Information System (INIS)

    Matute, Leonardo

    2000-01-01

    The paper describes the framework (organic structure and legislation) in promotion of renewables in Honduras, the policies for promotion of the free market of energy, laws on environmental protection and law of electricity. Also describes treties and agreements suscribed by Honduras in these matters

  4. Dynamical systems in population biology

    CERN Document Server

    Zhao, Xiao-Qiang

    2017-01-01

    This research monograph provides an introduction to the theory of nonautonomous semiflows with applications to population dynamics. It develops dynamical system approaches to various evolutionary equations such as difference, ordinary, functional, and partial differential equations, and pays more attention to periodic and almost periodic phenomena. The presentation includes persistence theory, monotone dynamics, periodic and almost periodic semiflows, basic reproduction ratios, traveling waves, and global analysis of prototypical population models in ecology and epidemiology. Research mathematicians working with nonlinear dynamics, particularly those interested in applications to biology, will find this book useful. It may also be used as a textbook or as supplementary reading for a graduate special topics course on the theory and applications of dynamical systems. Dr. Xiao-Qiang Zhao is a University Research Professor at Memorial University of Newfoundland, Canada. His main research interests involve applied...

  5. Drug resistance prevalence in human immunodeficiency virus type 1 infected pediatric populations in Honduras and El Salvador during 1989-2009.

    Science.gov (United States)

    Holguín, Africa; Erazo, Karen; Escobar, Gustavo; de Mulder, Miguel; Yebra, Gonzalo; Martín, Leticia; Jovel, Luis Enrique; Castaneda, Luis; Pérez, Elsy

    2011-05-01

    Emergence of viral resistance is a major obstacle for antiretroviral treatment (ART) effectiveness. Human immunodeficiency virus type-1 (HIV-1) variants and drug-resistance mutations were identified in naive and antiretroviral drug-experienced children with virologic failure, in Honduras and El Salvador. Dried blood spots (DBS) from 80 individuals (54 from Honduras, 26 from El Salvador) infected during their childhood between 1989 and 2009 were collected in 2009. The HIV pol region was amplified and sequenced to identify antiretroviral-resistant mutations according to the 2009 International AIDS Society. The genotypic drug resistance interpretation was performed using the Stanford algorithm. HIV-1 variants were characterized by phylogenetic analysis and subtyping tools. HIV-1 protease and reverse transcription sequences were obtained from DBS specimens in 71 and 66 patients, respectively, of the 80 patients. All children were native Central Americans carrying subtype B, with a mean age of 9 years, most were male (65%), perinatally infected (96%), with moderate/severe AIDS symptoms (70%), and receiving first line ART at the time of sequencing (65%). Diagnostic delay was frequently observed. Infected children from Honduras presented longer ART experience and clinical outcomes, and more frequent severe symptoms. Resistant variants infected 1 of 11 naive children from El Salvador but none of the perinatally infected naive children from Honduras. Resistance was higher among ART-exposed individuals in both countries and similar for protease inhibitors (16%), nucleoside reverse transcription inhibitors (44%-52%), and nonnucleoside reverse-transcription inhibitors (66.7%). One in 10 pretreated children in each country was infected with resistant viruses to the 3 drug families. Our data support the need for continued surveillance of resistance patterns using DBS at national levels among naive and pretreated children to optimize the ART regimens.

  6. Nonlinear Relaxation in Population Dynamics

    Science.gov (United States)

    Cirone, Markus A.; de Pasquale, Ferdinando; Spagnolo, Bernardo

    We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the ith population and on the distribution of the population and of the local field.

  7. Rapid ongoing decline of Baird's tapir in Cusuco National Park, Honduras.

    Science.gov (United States)

    McCANN, Niall P; Wheeler, Phil M; Coles, Tim; Bruford, Michael W

    2012-12-01

    During the International Tapir Symposium 16-21 Oct 2011, the conservation of Baird's tapir (Tapirus bairdii) in Honduras received a boost with the signing of a memorandum of understanding between the Minister Director of the Honduran Institute of Conservation and Forestry (ICF) and the Tapir Specialist Group (TSG). Despite this agreement, accelerating levels of hunting and habitat loss continue to pose a threat to Baird's tapir in Honduras. An ongoing study in Cusuco National Park in northwestern Honduras has been monitoring changes in population dynamics of Baird's tapir since 2006 through the collection of occupancy data. The study has identified an increase in hunting pressure, coinciding with a drastic decline in the encounter rate with Baird's tapir spoor. Here, we examine the significance of a range of demographic variables on Baird's tapir occupancy in Cusuco National Park using the software PRESENCE, and simulate the effects of different management strategies on the future dynamics of the population using the stochastic simulation software VORTEX. The predictions of the theoretical population models are compared to observed changes in occupancy levels. We found that non-intervention resulted in the local extinction of Baird's tapir within a very short time frame, but that various intervention models enabled the population to recover to near carrying capacity. Occupancy and extinction probability were shown to respond markedly to the increase in hunting pressure; and occupancy models supported the future population predictions generated by VORTEX. Our study suggests that immediate intervention is required to reduce hunting pressure to near historical levels to prevent the imminent local extinction of the species. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

  8. Population dynamics of rural Ethiopia.

    Science.gov (United States)

    Bariabagar, H

    1978-01-01

    2 rounds of the national sample surveys, conducted by the central statistical office of Ethiopia during 1964-1967 and 1969-1971, provide the only comprehensive demographic data for the country and are the basis for this discussion of rural Ethiopia's population dynamics. The population of Ethiopia is predominantly rural. Agglomerations of 2000 and over inhabitants constitute about 14% of the population, and this indicates that Ethiopia has a low level of urbanization. In rural Ethiopia, international migration was negligent in the 1970's and the age structure can be assumed to be the results of past trends of fertility and mortality conditions. The reported crude birthrate (38.2), crude death rate (12.3) and infant mortality rate (90) of rural Ethiopia fall short of the averages for African countries. Prospects of population growth of rural Ethiopia would be immense. At the rate of natural increase of between 2.4 and 3.0% per annum, the population would double in 24-29 years. Regarding population issues, the programs of the National Democratic Revolution of Ethiopia faces the following main challenging problems: 1) carrying out national population censuses in order to obtain basic information for socialist planning; 2) minimizing or curtailing the existing high urban growth rates; 3) reducing rapidly growing population; and 5) mobilizing Ethiopian women to participate in the social, economic and political life of the country in order to create favorable conditions for future fertility reduction.

  9. Population dynamics in variable environments

    CERN Document Server

    Tuljapurkar, Shripad

    1990-01-01

    Demography relates observable facts about individuals to the dynamics of populations. If the dynamics are linear and do not change over time, the classical theory of Lotka (1907) and Leslie (1945) is the central tool of demography. This book addresses the situation when the assumption of constancy is dropped. In many practical situations, a population will display unpredictable variation over time in its vital rates, which must then be described in statistical terms. Most of this book is concerned with the theory of populations which are subject to random temporal changes in their vital rates, although other kinds of variation (e. g. , cyclical) are also dealt with. The central questions are: how does temporal variation work its way into a population's future, and how does it affect our interpretation of a population's past. The results here are directed at demographers of humans and at popula­ tion biologists. The uneven mathematical level is dictated by the material, but the book should be accessible to re...

  10. Tracking financial flows for immunization in Honduras.

    Science.gov (United States)

    Valdés, Werner; Janusz, Cara Bess; Molina Aguilera, Ida Berenice; Mendoza, Lourdes; Díaz, Iris Yolanda; Resch, Stephen

    2015-05-07

    In Honduras, until 2008, vaccine and injection supplies were financed with domestic resources. With the introduction of rotavirus vaccine in 2009 and pneumococcal conjugate in 2011, the country's Expanded Program on Immunization required an influx of resources to support not only vaccine procurement but also investments in cold chain infrastructure and programmatic strategies. This paper examines the origin, allocation, and use of resources for immunization in 2011 in Honduras, with the aim of identifying gaps in financing. An adaptation of the System of Health Accounts (2011) codes was used to specifically track resources for immunization services in Honduras for 2011. All financial flows were entered into an Excel database, and each transfer of resources was coded with a financing source and a financing agent. These coded financing sources were then distributed by provider, health care function (activity), health care provision (line item or resource input), and beneficiary (geographic, population, and antigen). All costs were calculated in 2011 United States dollars. In 2011, financing for routine immunization in Honduras amounted to US$ 49.1 million, which is equal to 3.3% of the total health spending of US$ 1.49 billion and 0.29% of the GDP. Of the total financing, 64% originate from domestic sources. The other 36% is external financing, most importantly Gavi support for introducing new vaccines. This analysis identified potential financing gaps for many immunization-related activities besides procuring vaccines, such as expanding the cold chain, training, social mobilization, information systems, and research. The funding for Honduras' immunization program is a small share of total public spending on health. However, new vaccines recently added to the schedule with financial support from Gavi have increased the financing requirements by more than 30% in comparison to 2008. The Honduran government and its partners are developing sustainability plans to cover a

  11. FY16 Honduras Country Opinion Survey Report

    OpenAIRE

    World Bank Group

    2016-01-01

    The Country Opinion Survey in Honduras assists the World Bank Group (WBG) in gaining a better understanding of how stakeholders in Honduras perceive the WBG. It provides the WBG with systematic feedback from national and local governments, multilateral/bilateral agencies, media, academia, the private sector, and civil society in Honduras on 1) their views regarding the general environment ...

  12. Nonlinear dynamics of interacting populations

    CERN Document Server

    Bazykin, Alexander D

    1998-01-01

    This book contains a systematic study of ecological communities of two or three interacting populations. Starting from the Lotka-Volterra system, various regulating factors are considered, such as rates of birth and death, predation and competition. The different factors can have a stabilizing or a destabilizing effect on the community, and their interplay leads to increasingly complicated behavior. Studying and understanding this path to greater dynamical complexity of ecological systems constitutes the backbone of this book. On the mathematical side, the tool of choice is the qualitative the

  13. Analysis of Population Dynamics in World Economy

    OpenAIRE

    Martin, Gress

    2011-01-01

    Population dynamics is an important topic in current world economy. The size and growth of population have an impact on economic growth and development of individual countries and vice versa, economic development influences demographic variables in a country. The aim of the article is to analyze historical development of world population, population stock change and relations between population stock change and economic development.

  14. Allee effects on population dynamics with delay

    International Nuclear Information System (INIS)

    Celik, C.; Merdan, H.; Duman, O.; Akin, O.

    2008-01-01

    In this paper, we study the stability analysis of equilibrium points of population dynamics with delay when the Allee effect occurs at low population density. Mainly, our mathematical results and numerical simulations point to the stabilizing effect of the Allee effects on population dynamics with delay

  15. Honduras: Will the Revolution Come?

    Science.gov (United States)

    1983-06-03

    specifically, El Salvador and Nicar- 10 agua . Honduras’ status as the only country in the region with a freely convertible currency during most of...PACIFIC PANAMA OCEAN CQL0O74IA ECUADOR. ~--~ .. . ~ ~ ..... PERU ------- -~ PACIFIC OCEAN ( ~ AUY CHILE -~ ~~UR GUAY DEMOCRACIES ý’-’ AR G E N I’lA

  16. Mapa de Vulnerabilidad en Honduras

    Science.gov (United States)

    Sánchez, A. A.

    2013-05-01

    Dado que Honduras geográficamente se encuentra en una zona que esta expuesta a diferentes fenómenos sísmicos y climatológicos. Investigamos cuales son las zonas mas propensas a desastres naturales, la vulnerabilidad y el factor de resiliencia de la población de acuerdo a diferentes parámetros de estudio.

  17. Genetic diversity of Plasmodium vivax and Plasmodium falciparum in Honduras.

    Science.gov (United States)

    Lopez, Ana Cecilia; Ortiz, Andres; Coello, Jorge; Sosa-Ochoa, Wilfredo; Torres, Rosa E Mejia; Banegas, Engels I; Jovel, Irina; Fontecha, Gustavo A

    2012-11-26

    Understanding the population structure of Plasmodium species through genetic diversity studies can assist in the design of more effective malaria control strategies, particularly in vaccine development. Central America is an area where malaria is a public health problem, but little is known about the genetic diversity of the parasite's circulating species. This study aimed to investigate the allelic frequency and molecular diversity of five surface antigens in field isolates from Honduras. Five molecular markers were analysed to determine the genotypes of Plasmodium vivax and Plasmodium falciparum from endemic areas in Honduras. Genetic diversity of ama-1, msp-1 and csp was investigated for P. vivax, and msp-1 and msp-2 for P. falciparum. Allelic frequencies were calculated and sequence analysis performed. A high genetic diversity was observed within Plasmodium isolates from Honduras. A different number of genotypes were elucidated: 41 (n = 77) for pvama-1; 23 (n = 84) for pvcsp; and 23 (n = 35) for pfmsp-1. Pvcsp sequences showed VK210 as the only subtype present in Honduran isolates. Pvmsp-1 (F2) was the most polymorphic marker for P. vivax isolates while pvama-1 was least variable. All three allelic families described for pfmsp-1 (n = 30) block 2 (K1, MAD20, and RO33), and both allelic families described for the central domain of pfmsp-2 (n = 11) (3D7 and FC27) were detected. However, K1 and 3D7 allelic families were predominant. All markers were randomly distributed across the country and no geographic correlation was found. To date, this is the most complete report on molecular characterization of P. vivax and P. falciparum field isolates in Honduras with regards to genetic diversity. These results indicate that P. vivax and P. falciparum parasite populations are highly diverse in Honduras despite the low level of transmission.

  18. Population dynamics at high Reynolds number

    NARCIS (Netherlands)

    Perlekar, P.; Benzi, R.; Nelson, D.R.; Toschi, F.

    2010-01-01

    We study the statistical properties of population dynamics evolving in a realistic two-dimensional compressible turbulent velocity field. We show that the interplay between turbulent dynamics and population growth and saturation leads to quasi-localization and a remarkable reduction in the carrying

  19. The herpetofauna of Parque Nacional Pico Bonito, Honduras

    Directory of Open Access Journals (Sweden)

    James R. McCranie

    2005-10-01

    Full Text Available Seventy-three species of amphibians and reptiles (six salamanders, 20 anurans, 20 lizards, and 27 snakes are known from Parque Nacional Pico Bonito, Honduras. The physiography, climate, vegetation, and microhabitats of the park are briefly described. Forty-four species are recorded from Lowland Moist Forest, 45 from Premontane Wet Forest, and 14 from Lower Montane Wet Forest. The primary microhabitat and relative abundance of each species are indicated and population declines are discussed.

  20. Population dynamics and population control of Galium aparine L.

    NARCIS (Netherlands)

    Weide, van der R.Y.

    1993-01-01

    The population biology of Galium aparine L. needs to be better understood, in order to be able to rationalize decisions about the short- and long-term control of this weed species for different cropping practices.

    A population dynamics model was developed to

  1. provisional analysis of population dynamics

    Indian Academy of Sciences (India)

    Nicholas Mitchison

    2018-01-11

    Jan 11, 2018 ... Western populations covered by OMIM, or are so mediated to a lesser extent. This we attribute ... tlenecks affected southern Asia: a coalescence analysis of ... included comprehensive survey of previous work (Atkin- son et al.

  2. Population dynamics and rural poverty.

    Science.gov (United States)

    Fong, M S

    1985-01-01

    An overview of the relationship between demographic factors and rural poverty in developing countries is presented. The author examines both the micro- and macro-level perspectives of this relationship and the determinants and consequences of population growth. The author notes the prospects for a rapid increase in the rural labor force and considers its implications for the agricultural production structure and the need for institutional change. Consideration is also given to the continuing demand for high fertility at the family level and the role of infant and child mortality in the poverty cycle. "The paper concludes by drawing attention to the need for developing the mechanism for reconciliation of social and individual optima with respect to family size and population growth." The need for rural development projects that take demographic factors into account is stressed as is the need for effective population programs. (summary in FRE, ITA) excerpt

  3. POPULATION DYNAMICS OF PSEUDO-NITZSCHIA SPECIES ...

    African Journals Online (AJOL)

    nb

    current study aimed at assessing the population dynamics of Pseudo-nitzschia ... and to the developing aquaculture industry ... B. Hotel. Pangani Island. Bongoyo Island. Mbudya Island. Msasani Bay ... Salinity values did not show clear trends.

  4. Alternative education programmes and middle school dropout in Honduras

    Science.gov (United States)

    Marshall, Jeffery H.; Aguilar, Claudia R.; Alas, Mario; Castellanos, Renán Rápalo; Castro, Levi; Enamorado, Ramón; Fonseca, Esther

    2014-05-01

    Honduras has made steady progress in expanding post-primary school coverage in recent years, but many rural communities still do not provide a middle (lower secondary) school. As a result, Honduras has implemented a number of middle school alternative programmes designed to meet the needs of at-risk populations throughout the country. This article analyses dropout in three of the four main alternative lower secondary school programmes in Honduras over a three-year period for a cohort of roughly 5,500 students. The results show that these programmes are indeed reaching a vulnerable population in the country, but dropout rates are generally very high - upwards of 50 per cent in some cases - between Grades 7 and 9. Furthermore, even in the control school comparison samples made up of formal lower secondary schools, about 25 per cent of children leave school between Grades 7 and 9. The authors' analysis includes propensity score matching (PSM) methods that make more focused comparisons between students in alternative programmes and control samples. These results show that dropout rates in alternative programmes are not much different than in control schools, and only significant in one programme comparison, when taking into account family background characteristics like socioeconomic status (SES). Multivariate analysis within alternative programme samples finds that attrition is lower in those learning centres which have adopted key features of formal schools, such as university-educated teachers. The results highlight the tremendous variation in the alternative middle school sector in terms of programme features, school quality and student outcomes, as well as the challenges of expanding this sector to meet the growing demand for lower secondary schooling in Honduras.

  5. Evolutionary dynamics of cooperation in neutral populations

    Science.gov (United States)

    Szolnoki, Attila; Perc, Matjaž

    2018-01-01

    Cooperation is a difficult proposition in the face of Darwinian selection. Those that defect have an evolutionary advantage over cooperators who should therefore die out. However, spatial structure enables cooperators to survive through the formation of homogeneous clusters, which is the hallmark of network reciprocity. Here we go beyond this traditional setup and study the spatiotemporal dynamics of cooperation in a population of populations. We use the prisoner's dilemma game as the mathematical model and show that considering several populations simultaneously gives rise to fascinating spatiotemporal dynamics and pattern formation. Even the simplest assumption that strategies between different populations are payoff-neutral with one another results in the spontaneous emergence of cyclic dominance, where defectors of one population become prey of cooperators in the other population, and vice versa. Moreover, if social interactions within different populations are characterized by significantly different temptations to defect, we observe that defectors in the population with the largest temptation counterintuitively vanish the fastest, while cooperators that hang on eventually take over the whole available space. Our results reveal that considering the simultaneous presence of different populations significantly expands the complexity of evolutionary dynamics in structured populations, and it allows us to understand the stability of cooperation under adverse conditions that could never be bridged by network reciprocity alone.

  6. Stochastic population dynamic models as probability networks

    Science.gov (United States)

    M.E. and D.C. Lee. Borsuk

    2009-01-01

    The dynamics of a population and its response to environmental change depend on the balance of birth, death and age-at-maturity, and there have been many attempts to mathematically model populations based on these characteristics. Historically, most of these models were deterministic, meaning that the results were strictly determined by the equations of the model and...

  7. Modeling the population dynamics of Pacific yew.

    Science.gov (United States)

    Richard T. Busing; Thomas A. Spies

    1995-01-01

    A study of Pacific yew (Taxus brevifolia Nutt.) population dynamics in the mountains of western Oregon and Washington was based on a combination of long-term population data and computer modeling. Rates of growth and mortality were low in mature and old-growth forest stands. Diameter growth at breast height ranged from 0 to 3 centimeters per decade...

  8. Population dynamical responses to climate change

    DEFF Research Database (Denmark)

    Forchhammer, Mads; Schmidt, Niels Martin; Høye, Toke Thomas

    2008-01-01

    approaches, we analyse concurrently the influence of climatic variability and trophic interactions on the temporal population dynamics of species in the terrestrial vertebrate community at Zackenberg. We describe and contrast the population dynamics of three predator species (arctic fox Alopex lagopus, stoat...... of arctic fox were not significantly related to changes in lemming abundance, both the stoat and the breeding of long-tailed skua were mainly related to lemming dynamics. The predator-prey system at Zackenberg differentiates from previously described systems in high-arctic Greenland, which, we suggest...

  9. Population dynamics on heterogeneous bacterial substrates

    Science.gov (United States)

    Mobius, Wolfram; Murray, Andrew W.; Nelson, David R.

    2012-02-01

    How species invade new territories and how these range expansions influence the population's genotypes are important questions in the field of population genetics. The majority of work addressing these questions focuses on homogeneous environments. Much less is known about the population dynamics and population genetics when the environmental conditions are heterogeneous in space. To better understand range expansions in two-dimensional heterogeneous environments, we employ a system of bacteria and bacteriophage, the viruses of bacteria. Thereby, the bacteria constitute the environment in which a population of bacteriophages expands. The spread of phage constitutes itself in lysis of bacteria and thus formation of clear regions on bacterial lawns, called plaques. We study the population dynamics and genetics of the expanding page for various patterns of environments.

  10. How Resource Phenology Affects Consumer Population Dynamics.

    Science.gov (United States)

    Bewick, Sharon; Cantrell, R Stephen; Cosner, Chris; Fagan, William F

    2016-02-01

    Climate change drives uneven phenology shifts across taxa, and this can result in changes to the phenological match between interacting species. Shifts in the relative phenology of partner species are well documented, but few studies have addressed the effects of such changes on population dynamics. To explore this, we develop a phenologically explicit model describing consumer-resource interactions. Focusing on scenarios for univoltine insects, we show how changes in resource phenology can be reinterpreted as transformations in the year-to-year recursion relationships defining consumer population dynamics. This perspective provides a straightforward path for interpreting the long-term population consequences of phenology change. Specifically, by relating the outcome of phenological shifts to species traits governing recursion relationships (e.g., consumer fecundity or competitive scenario), we demonstrate how changes in relative phenology can force systems into different dynamical regimes, with major implications for resource management, conservation, and other areas of applied dynamics.

  11. Population Dynamics and Air Pollution

    DEFF Research Database (Denmark)

    Flachs, Esben Meulengracht; Sørensen, Jan; Bønløkke, Jacob

    2013-01-01

    Objective. To explore how three different assumptions on demographics affect the health impact of Danish emitted air pollution in Denmark from 2005 to 2030, with health impact modeled from 2005 to 2050. Methods. Modeled air pollution from Danish sources was used as exposure in a newly developed......) a static year 2005 population, (2) morbidity and mortality fixed at the year 2005 level, or (3) an expected development. Results. The health impact of air pollution was estimated at 672,000, 290,000, and 280,000 lost life years depending on demographic assumptions and the corresponding social costs at 430.......4 M€, 317.5 M€, and 261.6 M€ through the modeled years 2005–2050. Conclusion. The modeled health impact of air pollution differed widely with the demographic assumptions, and thus demographics and assumptions on demographics played a key role in making health impact assessments on air pollution....

  12. Population dynamics in vasopressin cells.

    Science.gov (United States)

    Leng, Gareth; Brown, Colin; Sabatier, Nancy; Scott, Victoria

    2008-01-01

    Most neurons sense and code change, and when presented with a constant stimulus they adapt, so as to be able to detect a fresh change. However, for some things it is important to know their absolute level; to encode such information, neurons must sustain their response to an unchanging stimulus while remaining able to respond to a change in that stimulus. One system that encodes the absolute level of a stimulus is the vasopressin system, which generates a hormonal signal that is proportional to plasma osmolality. Vasopressin cells sense plasma osmolality and secrete appropriate levels of vasopressin from the neurohypophysis as needed to control water excretion; this requires sustained secretion under basal conditions and the ability to increase (or decrease) secretion should plasma osmolality change. Here we explore the mechanisms that enable vasopressin cells to fulfill this function, and consider how coordination between the cells might distribute the secretory load across the population of vasopressin cells. 2008 S. Karger AG, Basel.

  13. Physical and sexual violence, mental health indicators, and treatment seeking among street-based population groups in Tegucigalpa, Honduras Violencia física y sexual, indicadores de salud mental y búsqueda de tratamiento en grupos de población en situación de calle en Tegucigalpa, Honduras

    Directory of Open Access Journals (Sweden)

    Javier Rio Navarro

    2012-05-01

    Full Text Available OBJECTIVE: To establish the prevalence of exposure to physical and sexual violence, mental health symptoms, and medical treatment-seeking behavior among three street-based subpopulation groups in Tegucigalpa, Honduras, and to assess the association between sociodemographic group, mental health indicators, and exposure to violence. METHODS: An anonymous, cross-sectional survey among randomly selected street-based adolescents, adults, and commercial sex workers (CSWs was undertaken at the end of 2010 in Tegucigalpa. Médecins Sans Frontières (MSF mapped places where the study population gathers. Stratified probability samples were drawn for all groups, using two-stage random sampling. Trained MSF staff administered on-site standardized face-to-face questionnaires. RESULTS: Self-reported exposure to severe physical violence in the previous year was 20.9% among street-based adolescents, 28.8% among adults, and 30.6% among CSWs. For the physical violence event self-defined as most severe, 50.0% of the adolescents, 81.4% of the adults, and 70.6% of the CSWs sought medical treatment. Their exposure to severe sexual violence was 8.6%, 28.8%, and 59.2%, respectively. After exposure to the self-defined most severe sexual violence event, 14.3% of adolescents, 31.9% of adults, and 29.1% of CSWs sought treatment. Common mental health and substance abuse symptoms were highly prevalent and strongly associated with exposure to physical (odds ratio 4.5, P OBJETIVO: Establecer la prevalencia de la exposición a la violencia física y sexual, los síntomas relacionados con la salud mental, y las conductas de búsqueda de tratamiento médico en tres grupos de subpoblaciones en situación de calle en Tegucigalpa, Honduras, y evaluar la asociación entre el grupo sociodemográfico, los indicadores de salud mental y la exposición a la violencia. MÉTODOS: A fines del 2010 en Tegucigalpa se llevó a cabo una encuesta transversal, de carácter anónimo, en

  14. Structural stability of nonlinear population dynamics.

    Science.gov (United States)

    Cenci, Simone; Saavedra, Serguei

    2018-01-01

    In population dynamics, the concept of structural stability has been used to quantify the tolerance of a system to environmental perturbations. Yet, measuring the structural stability of nonlinear dynamical systems remains a challenging task. Focusing on the classic Lotka-Volterra dynamics, because of the linearity of the functional response, it has been possible to measure the conditions compatible with a structurally stable system. However, the functional response of biological communities is not always well approximated by deterministic linear functions. Thus, it is unclear the extent to which this linear approach can be generalized to other population dynamics models. Here, we show that the same approach used to investigate the classic Lotka-Volterra dynamics, which is called the structural approach, can be applied to a much larger class of nonlinear models. This class covers a large number of nonlinear functional responses that have been intensively investigated both theoretically and experimentally. We also investigate the applicability of the structural approach to stochastic dynamical systems and we provide a measure of structural stability for finite populations. Overall, we show that the structural approach can provide reliable and tractable information about the qualitative behavior of many nonlinear dynamical systems.

  15. Structural stability of nonlinear population dynamics

    Science.gov (United States)

    Cenci, Simone; Saavedra, Serguei

    2018-01-01

    In population dynamics, the concept of structural stability has been used to quantify the tolerance of a system to environmental perturbations. Yet, measuring the structural stability of nonlinear dynamical systems remains a challenging task. Focusing on the classic Lotka-Volterra dynamics, because of the linearity of the functional response, it has been possible to measure the conditions compatible with a structurally stable system. However, the functional response of biological communities is not always well approximated by deterministic linear functions. Thus, it is unclear the extent to which this linear approach can be generalized to other population dynamics models. Here, we show that the same approach used to investigate the classic Lotka-Volterra dynamics, which is called the structural approach, can be applied to a much larger class of nonlinear models. This class covers a large number of nonlinear functional responses that have been intensively investigated both theoretically and experimentally. We also investigate the applicability of the structural approach to stochastic dynamical systems and we provide a measure of structural stability for finite populations. Overall, we show that the structural approach can provide reliable and tractable information about the qualitative behavior of many nonlinear dynamical systems.

  16. Particle algorithms for population dynamics in flows

    International Nuclear Information System (INIS)

    Perlekar, Prasad; Toschi, Federico; Benzi, Roberto; Pigolotti, Simone

    2011-01-01

    We present and discuss particle based algorithms to numerically study the dynamics of population subjected to an advecting flow condition. We discuss few possible variants of the algorithms and compare them in a model compressible flow. A comparison against appropriate versions of the continuum stochastic Fisher equation (sFKPP) is also presented and discussed. The algorithms can be used to study populations genetics in fluid environments.

  17. Exploiting social influence to magnify population-level behaviour change in maternal and child health: study protocol for a randomised controlled trial of network targeting algorithms in rural Honduras.

    Science.gov (United States)

    Shakya, Holly B; Stafford, Derek; Hughes, D Alex; Keegan, Thomas; Negron, Rennie; Broome, Jai; McKnight, Mark; Nicoll, Liza; Nelson, Jennifer; Iriarte, Emma; Ordonez, Maria; Airoldi, Edo; Fowler, James H; Christakis, Nicholas A

    2017-03-13

    Despite global progress on many measures of child health, rates of neonatal mortality remain high in the developing world. Evidence suggests that substantial improvements can be achieved with simple, low-cost interventions within family and community settings, particularly those designed to change knowledge and behaviour at the community level. Using social network analysis to identify structurally influential community members and then targeting them for intervention shows promise for the implementation of sustainable community-wide behaviour change. We will use a detailed understanding of social network structure and function to identify novel ways of targeting influential individuals to foster cascades of behavioural change at a population level. Our work will involve experimental and observational analyses. We will map face-to-face social networks of 30 000 people in 176 villages in Western Honduras, and then conduct a randomised controlled trial of a friendship-based network-targeting algorithm with a set of well-established care interventions. We will also test whether the proportion of the population targeted affects the degree to which the intervention spreads throughout the network. We will test scalable methods of network targeting that would not, in the future, require the actual mapping of social networks but would still offer the prospect of rapidly identifying influential targets for public health interventions. The Yale IRB and the Honduran Ministry of Health approved all data collection procedures (Protocol number 1506016012) and all participants will provide informed consent before enrolment. We will publish our findings in peer-reviewed journals as well as engage non-governmental organisations and other actors through venues for exchanging practical methods for behavioural health interventions, such as global health conferences. We will also develop a 'toolkit' for practitioners to use in network-based intervention efforts, including public

  18. Towards a Population Dynamics Theory for Evolutionary Computing: Learning from Biological Population Dynamics in Nature

    Science.gov (United States)

    Ma, Zhanshan (Sam)

    In evolutionary computing (EC), population size is one of the critical parameters that a researcher has to deal with. Hence, it was no surprise that the pioneers of EC, such as De Jong (1975) and Holland (1975), had already studied the population sizing from the very beginning of EC. What is perhaps surprising is that more than three decades later, we still largely depend on the experience or ad-hoc trial-and-error approach to set the population size. For example, in a recent monograph, Eiben and Smith (2003) indicated: "In almost all EC applications, the population size is constant and does not change during the evolutionary search." Despite enormous research on this issue in recent years, we still lack a well accepted theory for population sizing. In this paper, I propose to develop a population dynamics theory forEC with the inspiration from the population dynamics theory of biological populations in nature. Essentially, the EC population is considered as a dynamic system over time (generations) and space (search space or fitness landscape), similar to the spatial and temporal dynamics of biological populations in nature. With this conceptual mapping, I propose to 'transplant' the biological population dynamics theory to EC via three steps: (i) experimentally test the feasibility—whether or not emulating natural population dynamics improves the EC performance; (ii) comparatively study the underlying mechanisms—why there are improvements, primarily via statistical modeling analysis; (iii) conduct theoretical analysis with theoretical models such as percolation theory and extended evolutionary game theory that are generally applicable to both EC and natural populations. This article is a summary of a series of studies we have performed to achieve the general goal [27][30]-[32]. In the following, I start with an extremely brief introduction on the theory and models of natural population dynamics (Sections 1 & 2). In Sections 4 to 6, I briefly discuss three

  19. Population dynamics of Pseudo-nitzschia species ...

    African Journals Online (AJOL)

    The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es Salaam. Samples ...

  20. The failure rate dynamics in heterogeneous populations

    International Nuclear Information System (INIS)

    Cha, Ji Hwan; Finkelstein, Maxim

    2013-01-01

    Most populations encountered in real world are heterogeneous. In reliability applications, the mixture (observed) failure rate, obviously, can be considered as a measure of ‘average’ quality in these populations. However, in addition to this average measure, some variability characteristics for failure rates can be very helpful in describing the time-dependent changes in quality of heterogeneous populations. In this paper, we discuss variance and the coefficient of variation of the corresponding random failure rate as variability measures for items in heterogeneous populations. Furthermore, there is often a risk that items of poor quality are selected for important missions. Therefore, along with the ‘average quality’ of a population, more ‘conservative’ quality measures should be also defined and studied. For this purpose, we propose the percentile and the tail-mixture of the failure rates as the corresponding conservative measures. Some illustrative examples are given. -- Highlights: ► This paper provides the insight on the variability measures in heterogeneous populations. ► The conservative quality measures in heterogeneous populations are defined. ► The utility of these measures is illustrated by meaningful examples. ► This paper provides a better understanding of the dynamics in heterogeneous populations

  1. Prediction of Rainfall-Induced Landslides in Tegucigalpa, Honduras, Using a Hydro-Geotechnical Model

    Science.gov (United States)

    Garcia Urquia, Elias; Axelsson, K.

    2010-05-01

    Central America is constantly being affected by natural hazards. Among these events are hurricanes and earthquakes, capable of triggering landslides that can alter the natural landscape, destroy infrastructure and cause the death of people in the most important settlements of the region. Hurricane Mitch in October of 1998 was of particular interest for the region, since it provoked hundreds of rainfall-induced landslides, mainly in 4 different countries. Studies carried out after Hurricane Mitch have allowed researchers to identify the factors that contribute to slope instability in many vulnerable areas. As Tegucigalpa, Honduras was partially destroyed due to the various landslide and flooding events triggered by this devastating hurricane, various research teams have deepened in their investigations and have proposed measures to mitigate the effects of similar future incidents. A model coupling an infinite-slope analysis and a simple groundwater flow approach can serve as a basis to predict the occurrence of landslides in Tegucigalpa, Honduras as a function of topographic, hydrological and soil variables. A safety map showing the rainfall-triggered landslide risk zones for Tegucigalpa, Honduras is to be created. As opposed to previous safety maps in which only steady-state conditions are studied, this analysis is extended and different steady-state and quasi-dynamic scenarios are considered for comparison. For the purpose of the latter settings, a hydrological analysis that determines the rainfall extreme values and their return periods in Tegucigalpa will account for the influence of rainfall on the groundwater flow and strength of soils. It is known that the spatial distribution of various factors that contribute to the risk of landslides (i.e. soil thickness, conductivity and strength properties; rainfall intensity and duration; root strength; subsurface flow orientation) is hard to determine. However, an effort is done to derive correlations for these

  2. Evolutionary Dynamics and Diversity in Microbial Populations

    Science.gov (United States)

    Thompson, Joel; Fisher, Daniel

    2013-03-01

    Diseases such as flu and cancer adapt at an astonishing rate. In large part, viruses and cancers are so difficult to prevent because they are continually evolving. Controlling such ``evolutionary diseases'' requires a better understanding of the underlying evolutionary dynamics. It is conventionally assumed that adaptive mutations are rare and therefore will occur and sweep through the population in succession. Recent experiments using modern sequencing technologies have illuminated the many ways in which real population sequence data does not conform to the predictions of conventional theory. We consider a very simple model of asexual evolution and perform simulations in a range of parameters thought to be relevant for microbes and cancer. Simulation results reveal complex evolutionary dynamics typified by competition between lineages with different sets of adaptive mutations. This dynamical process leads to a distribution of mutant gene frequencies different than expected under the conventional assumption that adaptive mutations are rare. Simulated gene frequencies share several conspicuous features with data collected from laboratory-evolved yeast and the worldwide population of influenza.

  3. Delay differential systems for tick population dynamics.

    Science.gov (United States)

    Fan, Guihong; Thieme, Horst R; Zhu, Huaiping

    2015-11-01

    Ticks play a critical role as vectors in the transmission and spread of Lyme disease, an emerging infectious disease which can cause severe illness in humans or animals. To understand the transmission dynamics of Lyme disease and other tick-borne diseases, it is necessary to investigate the population dynamics of ticks. Here, we formulate a system of delay differential equations which models the stage structure of the tick population. Temperature can alter the length of time delays in each developmental stage, and so the time delays can vary geographically (and seasonally which we do not consider). We define the basic reproduction number [Formula: see text] of stage structured tick populations. The tick population is uniformly persistent if [Formula: see text] and dies out if [Formula: see text]. We present sufficient conditions under which the unique positive equilibrium point is globally asymptotically stable. In general, the positive equilibrium can be unstable and the system show oscillatory behavior. These oscillations are primarily due to negative feedback within the tick system, but can be enhanced by the time delays of the different developmental stages.

  4. Calculating evolutionary dynamics in structured populations.

    Directory of Open Access Journals (Sweden)

    Charles G Nathanson

    2009-12-01

    Full Text Available Evolution is shaping the world around us. At the core of every evolutionary process is a population of reproducing individuals. The outcome of an evolutionary process depends on population structure. Here we provide a general formula for calculating evolutionary dynamics in a wide class of structured populations. This class includes the recently introduced "games in phenotype space" and "evolutionary set theory." There can be local interactions for determining the relative fitness of individuals, but we require global updating, which means all individuals compete uniformly for reproduction. We study the competition of two strategies in the context of an evolutionary game and determine which strategy is favored in the limit of weak selection. We derive an intuitive formula for the structure coefficient, sigma, and provide a method for efficient numerical calculation.

  5. New project director for Honduras.

    Science.gov (United States)

    1984-01-01

    Miguel Machuca has been installed as project director for the Honduras Contraceptive Social Marketing Program (HCSMP). he was selected from a field of candidates with public and private sector experience in marketing, business management and program development. Machuca will direct the development of the social marketing program and work to establish a marketing function within ASHONPLAFA, the sponsoring organization for HCSMP. A major goal is to correct misinformation or lack of information about family planning methods among consumers and reatilers; for example, consumers worry about the side-effects of oral contraceptives (OCs) and many perceive subsidized products to be either experimental or discards. Easily understandable graphic package naterials are being prepared for OCs distributed through the program. Another goal is sales training. The project is scheduled to be launched in March 1984 with distribution of Perla, a standard dose OC. Radio spots and newspaper ads are being prepared to inform consumers that Perla can be purchased through pharmacies and small rural shops at the cost of US$.75/cycle. A low-dose OC, a condom and a vaginal tablet are scheduled to be added to the product line by December 1984. Market research on brand names, packaging and pricing of these products is currently being conducted. According the Machuca, his biggest challenge will be to maintain a balance between the need to comply with the policies and regulations of the various organizations involved with the HCSMP and the simultaneous need to promote and implement the entrepreneurial activities necessary to project goals.

  6. Critical dynamics in population vaccinating behavior.

    Science.gov (United States)

    Pananos, A Demetri; Bury, Thomas M; Wang, Clara; Schonfeld, Justin; Mohanty, Sharada P; Nyhan, Brendan; Salathé, Marcel; Bauch, Chris T

    2017-12-26

    Vaccine refusal can lead to renewed outbreaks of previously eliminated diseases and even delay global eradication. Vaccinating decisions exemplify a complex, coupled system where vaccinating behavior and disease dynamics influence one another. Such systems often exhibit critical phenomena-special dynamics close to a tipping point leading to a new dynamical regime. For instance, critical slowing down (declining rate of recovery from small perturbations) may emerge as a tipping point is approached. Here, we collected and geocoded tweets about measles-mumps-rubella vaccine and classified their sentiment using machine-learning algorithms. We also extracted data on measles-related Google searches. We find critical slowing down in the data at the level of California and the United States in the years before and after the 2014-2015 Disneyland, California measles outbreak. Critical slowing down starts growing appreciably several years before the Disneyland outbreak as vaccine uptake declines and the population approaches the tipping point. However, due to the adaptive nature of coupled behavior-disease systems, the population responds to the outbreak by moving away from the tipping point, causing "critical speeding up" whereby resilience to perturbations increases. A mathematical model of measles transmission and vaccine sentiment predicts the same qualitative patterns in the neighborhood of a tipping point to greatly reduced vaccine uptake and large epidemics. These results support the hypothesis that population vaccinating behavior near the disease elimination threshold is a critical phenomenon. Developing new analytical tools to detect these patterns in digital social data might help us identify populations at heightened risk of widespread vaccine refusal. Copyright © 2017 the Author(s). Published by PNAS.

  7. Population Model with a Dynamic Food Supply

    Science.gov (United States)

    Dickman, Ronald; da Silva Nascimento, Jonas

    2009-09-01

    We propose a simple population model including the food supply as a dynamic variable. In the model, survival of an organism depends on a certain minimum rate of food consumption; a higher rate of consumption is required for reproduction. We investigate the stationary behavior under steady food input, and the transient behavior of growth and decay when food is present initially but is not replenished. Under a periodic food supply, the system exhibits period-doubling bifurcations and chaos in certain ranges of the reproduction rate. Bifurcations and chaos are favored by a slow reproduction rate and a long period of food-supply oscillation.

  8. Noise-induced effects in population dynamics

    Science.gov (United States)

    Spagnolo, Bernardo; Cirone, Markus; La Barbera, Antonino; de Pasquale, Ferdinando

    2002-03-01

    We investigate the role of noise in the nonlinear relaxation of two ecosystems described by generalized Lotka-Volterra equations in the presence of multiplicative noise. Specifically we study two cases: (i) an ecosystem with two interacting species in the presence of periodic driving; (ii) an ecosystem with a great number of interacting species with random interaction matrix. We analyse the interplay between noise and periodic modulation for case (i) and the role of the noise in the transient dynamics of the ecosystem in the presence of an absorbing barrier in case (ii). We find that the presence of noise is responsible for the generation of temporal oscillations and for the appearance of spatial patterns in the first case. In the other case we obtain the asymptotic behaviour of the time average of the ith population and discuss the effect of the noise on the probability distributions of the population and of the local field.

  9. Dynamic analysis of a parasite population model

    Science.gov (United States)

    Sibona, G. J.; Condat, C. A.

    2002-03-01

    We study the dynamics of a model that describes the competitive interaction between an invading species (a parasite) and its antibodies in an living being. This model was recently used to examine the dynamical competition between Tripanosoma cruzi and its antibodies during the acute phase of Chagas' disease. Depending on the antibody properties, the model yields three types of outcomes, corresponding, respectively, to healing, chronic disease, and host death. Here, we study the dynamics of the parasite-antibody interaction with the help of simulations, obtaining phase trajectories and phase diagrams for the system. We show that, under certain conditions, the size of the parasite inoculation can be crucial for the infection outcome and that a retardation in the stimulated production of an antibody species may result in the parasite gaining a definitive advantage. We also find a criterion for the relative sizes of the parameters that are required if parasite-generated decoys are indeed to help the invasion. Decoys may also induce a qualitatively different outcome: a limit cycle for the antibody-parasite population phase trajectories.

  10. [Population dynamics and development in the Caribbean].

    Science.gov (United States)

    Boland, B

    1995-12-01

    The impact is examined of socioeconomic factors on Caribbean population dynamics. This work begins by describing the socioeconomic context of the late 1980s and early 1990s, under the influence of the economic changes and crises of the 1980s. The small size, openness, dependency, and lack of diversification of the Caribbean economies have made them vulnerable to external pressures. The Bahamas and Belize had economic growth rates exceeding 5% annually during 1981-90, but most of the countries had low or negative growth. Unemployment, poverty, the structural adjustment measures adopted in the mid-1980s, and declines in social spending exacerbated general economic conditions. In broad terms, the population situation of the Caribbean is marked by diversity of sizes and growth rates. A few countries oriented toward services and tourism had demographic growth rates exceeding 3%, while at least 7 had almost no growth or negative growth. Population growth rates reflected different combinations of natural increase and migration. Crude death rates ranged from around 5/1000 to 11/1000, except in Haiti, and all countries of the region except Haiti had life expectancies of 70 years or higher. Despite fertility decline, the average crude birth rate was still relatively high at 26/1000, and the rate of natural increase was 1.8% annually for the region. Nearly half of the regional population was under 15 or over 65 years old. The body of this work provides greater detail on mortality patterns, variations by sex, infant mortality, causes of death, and implications for policy. The discussion of fertility includes general patterns and trends, age specific fertility rates, contraceptive prevalence, levels of adolescent fertility and age factors in adolescent sexual behavior, characteristics of adolescent unions, contraceptive usage, health and social consequences of adolescent childbearing, and the search for solutions. The final section describes the magnitude and causes of

  11. Doing Business Economy Profile 2015 : Honduras

    OpenAIRE

    World Bank Group

    2014-01-01

    This economy profile for Doing Business 2015 presents the 11 Doing Business indicators for Honduras. To allow for useful comparison, the profile also provides data for other selected economies (comparator economies) for each indicator. Doing Business 2015 is the 12th edition in a series of annual reports measuring the regulations that enhance business activity and those that constrain it. ...

  12. West Indian Sojourners in Guatemala and Honduras

    Directory of Open Access Journals (Sweden)

    Ronald N. Harpelle

    2012-12-01

    Full Text Available Review of: Race, Nation, and West Indian Immigration to Honduras, 1890-1940. Glenn A. Chambers. Baton Rouge: Louisiana State University Press, 2010. xii +202 pp. (Cloth US$ 35.00Black Labor Migration in Caribbean Guatemala, 1882-1923. Frederick Douglass Opie. Gainesville: University Press of Florida, 2009. 145 pp. (Cloth US$ 65.00

  13. [National survey of blindness and avoidable visual impairment in Honduras].

    Science.gov (United States)

    Alvarado, Doris; Rivera, Belinda; Lagos, Luis; Ochoa, Mayra; Starkman, Ivette; Castillo, Mariela; Flores, Eduardo; Lansingh, Van C; Limburg, Hans; Silva, Juan Carlos

    2014-11-01

    To determine the prevalence of blindness and visual impairment in Honduras, its causes and the response by the health services to growing demand. A cross-sectional population study was conducted between June and December 2013 using the standard methodology of the Rapid Assessment of Avoidable Blindness. A random sample survey was done in 63 clusters of 50 individuals aged ≥ 50, representative of the country as a whole. Visual acuity (VA) was assessed using a Snellen eye chart, and the condition of the lens and posterior pole was examined by direct ophthalmoscopy. Cataract surgical coverage was calculated and an assessment made of its quality, the causes of VA 20/60 with available correction. The main barriers against cataract surgery were cost (27.7%) and the lack of availability or difficulty of geographical access to the treatment (24.6%). The prevalence of blindness and visual impairment in Honduras is similar to that of other Latin American countries. 67% of cases of blindness could be resolved by improving the response capacity of the ophthalmological services, especially of cataract surgery, improving optician services and incorporating eye care in primary health care.

  14. Salmonella in beef and produce from honduras.

    Science.gov (United States)

    Maradiaga, Martha; Miller, Mark F; Thompson, Leslie; Pond, Ansen; Gragg, Sara E; Echeverry, Alejandro; Garcia, Lyda G; Loneragan, Guy H; Brashears, Mindy M

    2015-03-01

    Salmonella continues to cause a considerable number of foodborne illnesses worldwide. The sources of outbreaks include contaminated meat and produce. The purpose of this study was to establish an initial investigation of the burden of Salmonella in produce and beef from Honduras by sampling retail markets and abattoirs. Retail produce samples (cantaloupes, cilantro, cucumbers, leafy greens, peppers, and tomatoes; n = 573) were purchased in three major cities of Honduras, and retail whole-muscle beef (n = 555) samples were also purchased in four major cities. Additionally, both hide and beef carcass (n = 141) samples were collected from two Honduran abattoirs. Whole-muscle beef samples were obtained using a sponge hydrated with buffered peptone water, and 10 ml of the buffered peptone water rinsate of each produce sample was collected with a dry sponge and placed in a bag to be transported back to the United States. Salmonella was detected using a commercially available, closeplatform PCR system, and positive samples were subjected to culture on selective media to obtain isolates. Overall, the prevalence of Salmonella-positive samples, based on PCR detection in Honduras (n = 555) retail beef was 10.1% (95% confidence interval = 7.8, 12.9), whereas 7.8% (n = 141) of beef carcass and hides samples were positive in both beef plants. The overall Salmonella prevalence for all produce samples (n = 573) collected was 2.1% (95% confidence interval = 1.2, 3.6). The most common serotypes identified in Honduras were Salmonella Typhimurium followed by Derby. These results provide an indication of Salmonella contamination of beef and produce in Honduras. Developing a Salmonella baseline for Latin America through an initial investigation like the one presented here contributes to a broader global understanding of the potential exposure through food, thus providing insight into the needs for control strategies.

  15. Allee effects on population dynamics in continuous (overlapping) case

    International Nuclear Information System (INIS)

    Merdan, H.; Duman, O.; Akin, O.; Celik, C.

    2009-01-01

    This paper presents the stability analysis of equilibrium points of a continuous population dynamics with delay under the Allee effect which occurs at low population density. The mathematical results and numerical simulations show the stabilizing role of the Allee effects on the stability of the equilibrium point of this population dynamics.

  16. Honduras - Public Financial Management and Public-Private Partnerships

    Data.gov (United States)

    Millennium Challenge Corporation — The Honduras Threshold Country Program (TCP) aims to increase the efficiency and transparency of public financial management (PFM) and public private partnerships...

  17. Dynamics of genome rearrangement in bacterial populations.

    Directory of Open Access Journals (Sweden)

    Aaron E Darling

    2008-07-01

    represent the first characterization of genome arrangement evolution in a bacterial population evolving outside laboratory conditions. Insight into the process of genomic rearrangement may further the understanding of pathogen population dynamics and selection on the architecture of circular bacterial chromosomes.

  18. The Coreidae of Honduras (Hemiptera: Coreidae).

    Science.gov (United States)

    Linares, Carlos A; Orozco, Jesus

    2017-01-01

    Coreidae bugs are mostly sap-sucking insects feeding on a variety of plants. Despite their abundance and economic importance in Honduras there is little information on the species, their distribution and affected crops. Since knowledge of pest species allows for better management of crops, we aimed to document the diversity of this economically important group. Specimens from four entomological collections in Honduras were studied and an exhaustive search of all available literature was conducted. A total of 2,036 insects were examined. The fauna of Honduran coreids is now composed of 68 species. Nineteen species are recorded for the country for the first time and 17 species were found only in literature. Little is known about the biology and economic importance of most of the species.

  19. Perturbation analysis of transient population dynamics using matrix projection models

    DEFF Research Database (Denmark)

    Stott, Iain

    2016-01-01

    Non-stable populations exhibit short-term transient dynamics: size, growth and structure that are unlike predicted long-term asymptotic stable, stationary or equilibrium dynamics. Understanding transient dynamics of non-stable populations is important for designing effective population management...... these methods to know exactly what is being measured. Despite a wealth of existing methods, I identify some areas that would benefit from further development....

  20. A new Nototriton (Caudata: Plethodontidae) from Parque Nacional Montaña de Botaderos in northeastern Honduras.

    Science.gov (United States)

    Townsend, Josiah H; Medina-flores, Melissa; Reyes-Calderón, Onán; Austin, James D

    2013-01-01

    The highlands of northeastern Honduras remain under-characterized in terms of biological diversity, as exemplified by the regularity of new amphibian and reptile taxa discoveries. Following the recent description of a new species of Nototriton from the Sierra de Agalta in northeastern Honduras, we report the discovery of a second new species of Nototriton from the nearby Parque Nacional Montaña de Botaderos. This new taxon, Nototriton mime sp. nov., is distinguished from other Nototriton by its distinctive pale brown dorsal coloration in adult males, relatively large nares, a relatively broad head, mitochondrial sequence divergence, and phylogenetic relationships, and is geographically isolated from other populations of Nototriton.

  1. Passivity analysis of higher order evolutionary dynamics and population games

    KAUST Repository

    Mabrok, Mohamed; Shamma, Jeff S.

    2017-01-01

    Evolutionary dynamics describe how the population composition changes in response to the fitness levels, resulting in a closed-loop feedback system. Recent work established a connection between passivity theory and certain classes of population

  2. DYNAMICS OF Cercospora zeina POPULATIONS IN MAIZE-BASED ...

    African Journals Online (AJOL)

    ACSS

    DYNAMICS OFCercospora zeina POPULATIONS IN MAIZE-BASED AGRO- ..... Population differentiation of Cercospora zeina in three districts of Uganda based on analysis of molecular variance ..... interactions: The example of the Erysiphe.

  3. Security Policies from a Spatial Perspective: the Case of Honduras

    Directory of Open Access Journals (Sweden)

    Lirio del Carmen Gutiérrez Rivera

    2014-06-01

    Full Text Available Public insecurity became a central issue for many Hondurans in the late 1990s, as crime, delinquency and homicide increased significantly in the isthmus. Honduras had the second highest homicide rate (35.1 per 100,000 in the region after El Salvador (50.2. per 100,000 . This social violence triggered insecurity and fear, which was further accompanied by the overall perception that the state was unable of relieving or protecting the population. This article looks at the failed attempts of the Honduran state to stop social violence and to control youth gang expansion by focusing on the security policies Cero Tolerancia (Zero Tolerance, Mano Dura (Iron Fist and the Ley Antimaras (Anti-Gang Law. It understands security policies as territorial strategies that attempt to reduce social violence and impose control.

  4. Dimensions of Child Sexual Abuse before Age 15 in Three Central American Countries: Honduras, El Salvador, and Guatemala

    Science.gov (United States)

    Speizer, Ilene S.; Goodwin, Mary; Whittle, Lisa; Clyde, Maureen; Rogers, Jennifer

    2008-01-01

    Objective: The prevalence of sexual abuse during childhood or adolescence varies depending on the definitions and age categories used. This study examines the first national, population-based data available on child sexual abuse that occurs before age 15 in three countries: El Salvador, Guatemala, and Honduras. This study uses comparable…

  5. Including the Disabled : The Chiminike Interactive Learning Center in Honduras

    OpenAIRE

    Maria Valéria Pena; Barbara Brakarz

    2003-01-01

    In the aftermath of Hurricane Mitch in 1998, the Honduras Interactive Environmental Learning and Science Promotion Project "Profuturo" was launched as a multi-sectoral effort designed to encourage and expand scientific, environmental, and cultural knowledge and management in the context of Honduras' sustainable development needs and ethnic diversity. Profuturo benefits Hondurans by providi...

  6. Effects of an invasive plant on population dynamics in toads.

    Science.gov (United States)

    Greenberg, Daniel A; Green, David M

    2013-10-01

    When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989-2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads' marshland breeding areas. Our results showed density-dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long-term time series to identify shifts in population dynamics coincident with the advent of population decline. © 2013 Society for Conservation Biology.

  7. Evolutionary dynamics with fluctuating population sizes and strong mutualism

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R.

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  8. Evolutionary dynamics with fluctuating population sizes and strong mutualism.

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  9. Examining the cost of delivering routine immunization in Honduras.

    Science.gov (United States)

    Janusz, Cara Bess; Castañeda-Orjuela, Carlos; Molina Aguilera, Ida Berenice; Felix Garcia, Ana Gabriela; Mendoza, Lourdes; Díaz, Iris Yolanda; Resch, Stephen C

    2015-05-07

    Many countries have introduced new vaccines and expanded their immunization programs to protect additional risk groups, thus raising the cost of routine immunization delivery. Honduras recently adopted two new vaccines, and the country continues to broaden the reach of its program to adolescents and adults. In this article, we estimate and examine the economic cost of the Honduran routine immunization program for the year 2011. The data were gathered from a probability sample of 71 health facilities delivering routine immunization, as well as 8 regional and 1 central office of the national immunization program. Data were collected on vaccinations delivered, staff time dedicated to the program, cold chain equipment and upkeep, vehicle use, infrastructure, and other recurrent and capital costs at each health facility and administrative office. Annualized economic costs were estimated from a modified societal perspective and reported in 2011 US dollars. With the addition of rotavirus and pneumococcal conjugate vaccines, the total cost for routine immunization delivery in Honduras for 2011 was US$ 32.5 million. Vaccines and related supplies accounted for 23% of the costs. Labor, cold chain, and vehicles represented 54%, 4%, and 1%, respectively. At the facility level, the non-vaccine system costs per dose ranged widely, from US$ 25.55 in facilities delivering fewer than 500 doses per year to US$ 2.84 in facilities with volume exceeding 10,000 doses per year. Cost per dose was higher in rural facilities despite somewhat lower wage rates for health workers in these settings; this appears to be driven by lower demand for services per health worker in sparsely populated areas, rather than increased cost of outreach. These more-precise estimates of the operational costs to deliver routine immunizations provide program managers with important information for mobilizing resources to help sustain the program and for improving annual planning and budgeting as well as longer

  10. Population dynamics model for plasmid bearing and plasmid lacking ...

    African Journals Online (AJOL)

    Streptokinase production in bioreactor is well associated to cell population dynamics. It is an established fact that two types of cell populations are found to emerge from the initial pool of recombinant cell population. This phenomenon leads to an undesired loss in yield of the product. Primary metabolites, like acetic acid etc ...

  11. The influence of traditional and complementary and alternative medicine on medication adherence in Honduras.

    Science.gov (United States)

    Catalino, Michael Paul; Durón, Reyna Maria; Bailey, Julia Nancy; Holden, Kenton Roy

    2015-01-01

    Adherence to medication is a worldwide problem and deserves country-specific attention. Honduras, like many other countries, has allopathic providers, traditional medicine (TM), and complementary and alternative medicine (CAM). Understanding a population's health behaviors is essential to satisfactory integration of these systems and successful patient care. The objective was to identify factors that influence medication adherence in Honduras. The research team administered a cross-sectional, 25-item questionnaire to various neighborhoods based on national demographic statistics in order to obtain a quota sample. Setting • The survey took place in Tegucigalpa, Honduras, Central America. The research team surveyed 614 Hondurans, aged ≥ 18 y, within the general population of Tegucigalpa, the largest and capital city of Honduras, in neighborhoods representing areas where primarily the lower and middle classes lived. The primary outcome measure was a modified Medication Adherence Report Scale (MARS). Results • The research team collected 610 surveys that had complete answers to questions about adherence (610/614, 99.3%) total complete responses to other items varied. The prevalence of use of TM was 62.8% (381/607). Nearly one-half, 47.3% (287/607), of all the respondents had used herbs or teas for health in the prior year, and 26.1% (159/607) of all respondents had received a sobada (therapeutic rubbing). Respondents with daily private spiritual devotions (OR = 0.610, P = .018) and diabetes (OR = 0.154, P = .004) were less likely to report low adherence. Receiving a sobada and a history of fever were independently associated with low adherence (OR = 1.718, P = .017 and OR = 2.226, P < .001, respectively). Hondurans use both allopathic and TM. Although private spiritual devotion may help improve adherence to medication, only use of traditional massage therapy, the sobada, was associated with decreased adherence. Effective integration of alternative therapies in

  12. Stochastic population dynamics under resource constraints

    Energy Technology Data Exchange (ETDEWEB)

    Gavane, Ajinkya S., E-mail: ajinkyagavane@gmail.com; Nigam, Rahul, E-mail: rahul.nigam@hyderabad.bits-pilani.ac.in [BITS Pilani Hyderabad Campus, Shameerpet, Hyd - 500078 (India)

    2016-06-02

    This paper investigates the population growth of a certain species in which every generation reproduces thrice over a period of predefined time, under certain constraints of resources needed for survival of population. We study the survival period of a species by randomizing the reproduction probabilities within a window at same predefined ages and the resources are being produced by the working force of the population at a variable rate. This randomness in the reproduction rate makes the population growth stochastic in nature and one cannot predict the exact form of evolution. Hence we study the growth by running simulations for such a population and taking an ensemble averaged over 500 to 5000 such simulations as per the need. While the population reproduces in a stochastic manner, we have implemented a constraint on the amount of resources available for the population. This is important to make the simulations more realistic. The rate of resource production then is tuned to find the rate which suits the survival of the species. We also compute the mean life time of the species corresponding to different resource production rate. Study for these outcomes in the parameter space defined by the reproduction probabilities and rate of resource production is carried out.

  13. Stochastic dynamics and logistic population growth

    Science.gov (United States)

    Méndez, Vicenç; Assaf, Michael; Campos, Daniel; Horsthemke, Werner

    2015-06-01

    The Verhulst model is probably the best known macroscopic rate equation in population ecology. It depends on two parameters, the intrinsic growth rate and the carrying capacity. These parameters can be estimated for different populations and are related to the reproductive fitness and the competition for limited resources, respectively. We investigate analytically and numerically the simplest possible microscopic scenarios that give rise to the logistic equation in the deterministic mean-field limit. We provide a definition of the two parameters of the Verhulst equation in terms of microscopic parameters. In addition, we derive the conditions for extinction or persistence of the population by employing either the momentum-space spectral theory or the real-space Wentzel-Kramers-Brillouin approximation to determine the probability distribution function and the mean time to extinction of the population. Our analytical results agree well with numerical simulations.

  14. Seasonal population dynamics and energy consumption by ...

    African Journals Online (AJOL)

    Dynamiques saisonnières de population et consommation énergétique par les oiseaux aquatiques d'un petit estuaire tempéré De simples mesures des dynamiques de population et de consommation énergétique peuvent fournir des informations de base sur le rôle des consommateurs au sein des réseaux trophiques, ...

  15. Statistical dynamics of regional populations and economies

    Science.gov (United States)

    Huo, Jie; Wang, Xu-Ming; Hao, Rui; Wang, Peng

    Quantitative analysis of human behavior and social development is becoming a hot spot of some interdisciplinary studies. A statistical analysis on the population and GDP of 150 cities in China from 1990 to 2013 is conducted. The result indicates the cumulative probability distribution of the populations and that of the GDPs obeying the shifted power law, respectively. In order to understand these characteristics, a generalized Langevin equation describing variation of population is proposed, which is based on the correlations between population and GDP as well as the random fluctuations of the related factors. The equation is transformed into the Fokker-Plank equation to express the evolution of population distribution. The general solution demonstrates a transition of the distribution from the normal Gaussian distribution to a shifted power law, which suggests a critical point of time at which the transition takes place. The shifted power law distribution in the supercritical situation is qualitatively in accordance with the practical result. The distribution of the GDPs is derived from the well-known Cobb-Douglas production function. The result presents a change, in supercritical situation, from a shifted power law to the Gaussian distribution. This is a surprising result-the regional GDP distribution of our world will be the Gaussian distribution one day in the future. The discussions based on the changing trend of economic growth suggest it will be true. Therefore, these theoretical attempts may draw a historical picture of our society in the aspects of population and economy.

  16. Development of a point-of-use fortification technology for delivery of micronutrients in Honduras.

    Science.gov (United States)

    Andrade, Juan E; Rosales, Eliana; Lopez, Julio R; Carrillo, E Paola; Engeseth, Nicki J; Helferich, William G

    2015-01-01

    Micronutrient deficiencies continue to afflict children rural populations around the world. A micronutrient delivery vehicle (MDV) was developed as a point-of-use technology for fortification of meals for school-age children beneficiaries of the Healthy Schools Program (HSP) in Honduras. MDV combines micronutrient powder through a traditional dough-making process, using staple flours (wheat and nixtamalized corn), oil and water as ingredients. After mixing the ingredients and kneading, dough is extruded through a specially designed hand press into noodles. After drying (overnight, 23°C), noodles are broken into small pieces, mixed (1:100 w/w) with rice and cooked as customary. Dispersion studies with NaFeEDTA showed adequate distribution (90%) in white rice. Color changes in MDV due to addition of vitamin A and iron (NaFeEDTA) carried forward into cooked rice. In Honduras, children from two rural schools (N = 47, 6-12 years) were not able to differentiate (triangle test) between control and unfortified MDV mixed (1:100 w/w) with white rice. Children from four schools (N = 83, 7-12 years) accepted control and iron fortified rice (3 mg Fe per serving) based on color and flavor similarly. This is a feasible point-of-use fortification technology for improvement of meals provided by the HSP in Honduras. © 2014 Society of Chemical Industry.

  17. Missing cycles: Effect of climate change on population dynamics

    Indian Academy of Sciences (India)

    population dynamics of the larch budmoth – an insect pest which causes massive defoliation of entire larch forests ... hypothesized that global warming has led to the collapse of the cycles ... When temperatures increase after winter, and the.

  18. A linear model of population dynamics

    Science.gov (United States)

    Lushnikov, A. A.; Kagan, A. I.

    2016-08-01

    The Malthus process of population growth is reformulated in terms of the probability w(n,t) to find exactly n individuals at time t assuming that both the birth and the death rates are linear functions of the population size. The master equation for w(n,t) is solved exactly. It is shown that w(n,t) strongly deviates from the Poisson distribution and is expressed in terms either of Laguerre’s polynomials or a modified Bessel function. The latter expression allows for considerable simplifications of the asymptotic analysis of w(n,t).

  19. Nesting Ecology of Hawksbill Sea Turtles (Eretmochelys imbricata) on Utila, Honduras

    Science.gov (United States)

    Damazo, Lindsey Renee Eggers

    The hawksbill sea turtle (Eretmochelys imbricata) has a circumtropical distribution and plays an important role in maintaining the health of coral reefs. Unfortunately, hawksbill populations have been decimated, and estimated numbers in the Caribbean are less than 10% of populations a century ago. The hawksbill is considered Critically Endangered, and researchers are coordinating worldwide efforts to protect this species. One country where we lack knowledge regarding hawksbills is Honduras. This study aimed to increase our understanding of hawksbill nesting ecology in Caribbean Honduras. Characteristics of hawksbill nesting activity and a nesting beach on the island of Utila were elucidated using satellite telemetry, beach profiling, vegetation surveys, beach monitoring, and nest temperature profiles. We affixed satellite transmitters to two nesting hawksbills, and found the turtles migrated to different countries. One turtle traveled 403 km to a bay in Mexico, and the other traveled 181 km to a Marine Protected Area off Belize. This study presents the first description of hawksbill migration routes from Honduras, facilitating protection efforts for turtles that traverse international waters. To investigate nesting beach and turtle characteristics, we conducted beach monitoring during the 2012 nesting season. Nesting turtle carapace sizes were similar to worldwide values, but hatchlings were heavier. To measure nest temperatures, we placed thermocouple data loggers in four nests and four pseudo-nests. Data suggested metabolic heating may be maintaining nest temperatures above the pivotal temperature. However, large temperature fluctuations corresponding to rainfall from Hurricane Ernesto (as determined using a time series cross-correlation analysis) make it difficult to predict sex ratios, and underscore the impact stochastic events can have on nest temperatures. We created topographic and substrate profiles of the beach, and found it was 475 m long, yet hawksbills

  20. Dynamics of a structured neuron population

    International Nuclear Information System (INIS)

    Pakdaman, Khashayar; Salort, Delphine; Perthame, Benoît

    2010-01-01

    We study the dynamics of assemblies of interacting neurons. For large fully connected networks, the dynamics of the system can be described by a partial differential equation reminiscent of age-structure models used in mathematical ecology, where the 'age' of a neuron represents the time elapsed since its last discharge. The nonlinearity arises from the connectivity J of the network. We prove some mathematical properties of the model that are directly related to qualitative properties. On the one hand, we prove that it is well-posed and that it admits stationary states which, depending upon the connectivity, can be unique or not. On the other hand, we study the long time behaviour of solutions; both for small and large J, we prove the relaxation to the steady state describing asynchronous firing of the neurons. In the middle range, numerical experiments show that periodic solutions appear expressing re-synchronization of the network and asynchronous firing

  1. POPULATION DYNAMICS OF THE WANDERING ALBATROSS ...

    African Journals Online (AJOL)

    Changes in several demographic parameters that appear to be influenced by both environmental and anthropogenic effects are described. From 1994–2001, the proportion of first-time breeders in the population was positively correlated with the maximum ENSO (Niño 3) index, whereas from 1984–2000 the annual survival ...

  2. Stochastic population dynamics of a montane ground-dwelling squirrel.

    Science.gov (United States)

    Hostetler, Jeffrey A; Kneip, Eva; Van Vuren, Dirk H; Oli, Madan K

    2012-01-01

    Understanding the causes and consequences of population fluctuations is a central goal of ecology. We used demographic data from a long-term (1990-2008) study and matrix population models to investigate factors and processes influencing the dynamics and persistence of a golden-mantled ground squirrel (Callospermophilus lateralis) population, inhabiting a dynamic subalpine habitat in Colorado, USA. The overall deterministic population growth rate λ was 0.94±SE 0.05 but it varied widely over time, ranging from 0.45±0.09 in 2006 to 1.50±0.12 in 2003, and was below replacement (λbounce back from low densities and prevented extinction. These results suggest that dynamics and persistence of our study population are determined synergistically by density-dependence, stochastic forces, and immigration.

  3. Passivity analysis of higher order evolutionary dynamics and population games

    KAUST Repository

    Mabrok, Mohamed

    2017-01-05

    Evolutionary dynamics describe how the population composition changes in response to the fitness levels, resulting in a closed-loop feedback system. Recent work established a connection between passivity theory and certain classes of population games, namely so-called “stable games”. In particular, it was shown that a combination of stable games and (an analogue of) passive evolutionary dynamics results in stable convergence to Nash equilibrium. This paper considers the converse question of necessary conditions for evolutionary dynamics to exhibit stable behaviors for all generalized stable games. Using methods from robust control analysis, we show that if an evolutionary dynamic does not satisfy a passivity property, then it is possible to construct a generalized stable game that results in instability. The results are illustrated on selected evolutionary dynamics with particular attention to replicator dynamics, which are also shown to be lossless, a special class of passive systems.

  4. Population dynamics and distribution of the coffee berry borer ...

    African Journals Online (AJOL)

    Population dynamics and distribution of coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae) were studied on Coffea arabica L. in southwestern region of Ethiopia. Thirty coffee trees were sampled at weekly intervals from 2000 to 2001. Findings of this study showed that coffee berry borer population ...

  5. Ruffed grouse population dynamics in the central and southern Appalachians

    Science.gov (United States)

    John M. Giuliano Tirpak; C. Allan Miller; Thomas J. Allen; Steve Bittner; David A. Buehler; John W. Edwards; Craig A. Harper; William K. Igo; Gary W. Norman; M. Seamster; Dean F. Stauffer

    2006-01-01

    Ruffed grouse (Bonasa urnbellus; hereafter grouse) populations in the central and southern Appalachians are in decline. However, limited information on the dynamics of these populations prevents the development of effective management strategies to reverse these trends. We used radiotelemetry data collected on grouse to parameterize 6 models of...

  6. Stage-Structured Population Dynamics of AEDES AEGYPTI

    Science.gov (United States)

    Yusoff, Nuraini; Budin, Harun; Ismail, Salemah

    Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.

  7. [The dynamics of heath indicators of population of industrial town].

    Science.gov (United States)

    Kalinkin, D E; Karpov, A B; Takhauov, R M; Samoĭlova, Iu A

    2013-01-01

    The article presents the results of analysis of dynamics of health indicators of population of industrial town (medical demographic indicators, disability, morbidity of social hygienically important diseases) during 1970-2010. The classified administrative territorial municipality of Seversk constructed near the Siberian chemical industrial center, the internationally first-rate complex of nuclear industry enterprises was used as a research base. It is demonstrated that dynamics of health indicators of studied population had such negative tendencies as rapid population ageing, population loss due to decrease of natality and increase of mortality (population of able-bodied age included), prevalence of cardio-vascular diseases, malignant neoplasms and external causes, chronization of diseases. The established tendencies are to be considered in management decision making targeted to support and promote population health in industrial towns.

  8. All projects related to Honduras | Page 2 | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Leveraging the Development of Inclusive and Sustainable Agricultural Value Chains ... Poor urban communities in most countries in Latin America and the ... South America, Chile, Colombia, Honduras, North and Central America, Mexico.

  9. Dynamics of Population on the Verge of Extinction

    OpenAIRE

    Oborny, B.; Meszena, G.; Szabo, G.

    2005-01-01

    Theoretical considerations suggest that extinction in dispersal-limited populations is necessarily a threshold-like process that is analogous to a critical phase transition in physics. We use this analogy to find robust, common features in the dynamics of extinctions, and suggest early warning signals which may indicate that a population is endangered. As the critical threshold of extinction is approached, the population spontaneously fragments into discrete subpopulations and, consequently, ...

  10. Geography, European colonization, and past population dynamics in Africa

    OpenAIRE

    Vaz Silva, Luis

    2005-01-01

    Past population dynamics in Africa have remained largely elusive due to the lack of demographic data. Researchers are understandably deterred from trying to explain what is not known and African historical population estimates suffer from this lack of interest. In this paper I explain present day African population densities using mostly ecological factors as explanatory variables. I find evidence supporting the view that ecological factors deeply affected precolonial patterns of human settle...

  11. Modelling the Dynamics of an Aedes albopictus Population

    Directory of Open Access Journals (Sweden)

    Thomas Anung Basuki

    2010-08-01

    Full Text Available We present a methodology for modelling population dynamics with formal means of computer science. This allows unambiguous description of systems and application of analysis tools such as simulators and model checkers. In particular, the dynamics of a population of Aedes albopictus (a species of mosquito and its modelling with the Stochastic Calculus of Looping Sequences (Stochastic CLS are considered. The use of Stochastic CLS to model population dynamics requires an extension which allows environmental events (such as changes in the temperature and rainfalls to be taken into account. A simulator for the constructed model is developed via translation into the specification language Maude, and used to compare the dynamics obtained from the model with real data.

  12. Exports, Gender Wage Gaps and Poverty in Honduras

    OpenAIRE

    de Hoyos, Rafael E.; Bussolo, Maurizio; Núñez, Oscar

    2012-01-01

    This paper identifies and estimates the reduction in poverty attributable to the improved opportunities that international trade integration offered to women in Honduras. The expansion of the export-oriented maquila sector has brought gender equality both in terms of employment and labour earnings. A simulation exercise shows that, at a given point in time, poverty in Honduras would have been 1.5 percentage points higher had the maquila sector not existed. Of this increase in poverty, 0.35 pe...

  13. A Multiorganization Approach to Improving Palliative Care in Honduras.

    Science.gov (United States)

    Kennedy Sheldon, Lisa; Dahlin, Constance; Maingi, Shail; Sanchez, Jose

    2017-01-01

    Since 2011, oncology nurses and physicians in the United States have been volunteering in Honduras with the International Cancer Corps (ICC), organized by the American Society of Clinical Oncology (ASCO), in partnership with Health Volunteers Overseas (HVO). In this article, the authors will summarize the work of the ASCO/HVO ICC teams that developed educational programs with local partners to improve cancer and palliative care in Honduras.

  14. Coupling population dynamics with earth system models: the POPEM model.

    Science.gov (United States)

    Navarro, Andrés; Moreno, Raúl; Jiménez-Alcázar, Alfonso; Tapiador, Francisco J

    2017-09-16

    Precise modeling of CO 2 emissions is important for environmental research. This paper presents a new model of human population dynamics that can be embedded into ESMs (Earth System Models) to improve climate modeling. Through a system dynamics approach, we develop a cohort-component model that successfully simulates historical population dynamics with fine spatial resolution (about 1°×1°). The population projections are used to improve the estimates of CO 2 emissions, thus transcending the bulk approach of existing models and allowing more realistic non-linear effects to feature in the simulations. The module, dubbed POPEM (from Population Parameterization for Earth Models), is compared with current emission inventories and validated against UN aggregated data. Finally, it is shown that the module can be used to advance toward fully coupling the social and natural components of the Earth system, an emerging research path for environmental science and pollution research.

  15. Dynamical community structure of populations evolving on genotype networks

    International Nuclear Information System (INIS)

    Capitán, José A.; Aguirre, Jacobo; Manrubia, Susanna

    2015-01-01

    Neutral evolutionary dynamics of replicators occurs on large and heterogeneous networks of genotypes. These networks, formed by all genotypes that yield the same phenotype, have a complex architecture that conditions the molecular composition of populations and their movements on genome spaces. Here we consider as an example the case of populations evolving on RNA secondary structure neutral networks and study the community structure of the network revealed through dynamical properties of the population at equilibrium and during adaptive transients. We unveil a rich hierarchical community structure that, eventually, can be traced back to the non-trivial relationship between RNA secondary structure and sequence composition. We demonstrate that usual measures of modularity that only take into account the static, topological structure of networks, cannot identify the community structure disclosed by population dynamics

  16. Dynamics of epidemics outbreaks in heterogeneous populations

    Science.gov (United States)

    Brockmann, Dirk; Morales-Gallardo, Alejandro; Geisel, Theo

    2007-03-01

    The dynamics of epidemic outbreaks have been investigated in recent years within two alternative theoretical paradigms. The key parameter of mean field type of models such as the SIR model is the basic reproduction number R0, the average number of secondary infections caused by one infected individual. Recently, scale free network models have received much attention as they account for the high variability in the number of social contacts involved. These models predict an infinite basic reproduction number in some cases. We investigate the impact of heterogeneities of contact rates in a generic model for epidemic outbreaks. We present a system in which both the time periods of being infectious and the time periods between transmissions are Poissonian processes. The heterogeneities are introduced by means of strongly variable contact rates. In contrast to scale free network models we observe a finite basic reproduction number and, counterintuitively a smaller overall epidemic outbreak as compared to the homogeneous system. Our study thus reveals that heterogeneities in contact rates do not necessarily facilitate the spread to infectious disease but may well attenuate it.

  17. Computer simulation of population dynamics inside the urban environment

    Science.gov (United States)

    Andreev, A. S.; Inovenkov, I. N.; Echkina, E. Yu.; Nefedov, V. V.; Ponomarenko, L. S.; Tikhomirov, V. V.

    2017-12-01

    In this paper using a mathematical model of the so-called “space-dynamic” approach we investigate the problem of development and temporal dynamics of different urban population groups. For simplicity we consider an interaction of only two population groups inside a single urban area with axial symmetry. This problem can be described qualitatively by a system of two non-stationary nonlinear differential equations of the diffusion type with boundary conditions of the third type. The results of numerical simulations show that with a suitable choice of the diffusion coefficients and interaction functions between different population groups we can receive different scenarios of population dynamics: from complete displacement of one population group by another (originally more “aggressive”) to the “peaceful” situation of co-existence of them together.

  18. Bounds on the dynamics of sink populations with noisy immigration.

    Science.gov (United States)

    Eager, Eric Alan; Guiver, Chris; Hodgson, Dave; Rebarber, Richard; Stott, Iain; Townley, Stuart

    2014-03-01

    Sink populations are doomed to decline to extinction in the absence of immigration. The dynamics of sink populations are not easily modelled using the standard framework of per capita rates of immigration, because numbers of immigrants are determined by extrinsic sources (for example, source populations, or population managers). Here we appeal to a systems and control framework to place upper and lower bounds on both the transient and future dynamics of sink populations that are subject to noisy immigration. Immigration has a number of interpretations and can fit a wide variety of models found in the literature. We apply the results to case studies derived from published models for Chinook salmon (Oncorhynchus tshawytscha) and blowout penstemon (Penstemon haydenii). Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Strongly Deterministic Population Dynamics in Closed Microbial Communities

    Directory of Open Access Journals (Sweden)

    Zak Frentz

    2015-10-01

    Full Text Available Biological systems are influenced by random processes at all scales, including molecular, demographic, and behavioral fluctuations, as well as by their interactions with a fluctuating environment. We previously established microbial closed ecosystems (CES as model systems for studying the role of random events and the emergent statistical laws governing population dynamics. Here, we present long-term measurements of population dynamics using replicate digital holographic microscopes that maintain CES under precisely controlled external conditions while automatically measuring abundances of three microbial species via single-cell imaging. With this system, we measure spatiotemporal population dynamics in more than 60 replicate CES over periods of months. In contrast to previous studies, we observe strongly deterministic population dynamics in replicate systems. Furthermore, we show that previously discovered statistical structure in abundance fluctuations across replicate CES is driven by variation in external conditions, such as illumination. In particular, we confirm the existence of stable ecomodes governing the correlations in population abundances of three species. The observation of strongly deterministic dynamics, together with stable structure of correlations in response to external perturbations, points towards a possibility of simple macroscopic laws governing microbial systems despite numerous stochastic events present on microscopic levels.

  20. Feedback between Population and Evolutionary Dynamics Determines the Fate of Social Microbial Populations

    Science.gov (United States)

    Sanchez, Alvaro; Gore, Jeff

    2013-01-01

    The evolutionary spread of cheater strategies can destabilize populations engaging in social cooperative behaviors, thus demonstrating that evolutionary changes can have profound implications for population dynamics. At the same time, the relative fitness of cooperative traits often depends upon population density, thus leading to the potential for bi-directional coupling between population density and the evolution of a cooperative trait. Despite the potential importance of these eco-evolutionary feedback loops in social species, they have not yet been demonstrated experimentally and their ecological implications are poorly understood. Here, we demonstrate the presence of a strong feedback loop between population dynamics and the evolutionary dynamics of a social microbial gene, SUC2, in laboratory yeast populations whose cooperative growth is mediated by the SUC2 gene. We directly visualize eco-evolutionary trajectories of hundreds of populations over 50–100 generations, allowing us to characterize the phase space describing the interplay of evolution and ecology in this system. Small populations collapse despite continual evolution towards increased cooperative allele frequencies; large populations with a sufficient number of cooperators “spiral” to a stable state of coexistence between cooperator and cheater strategies. The presence of cheaters does not significantly affect the equilibrium population density, but it does reduce the resilience of the population as well as its ability to adapt to a rapidly deteriorating environment. Our results demonstrate the potential ecological importance of coupling between evolutionary dynamics and the population dynamics of cooperatively growing organisms, particularly in microbes. Our study suggests that this interaction may need to be considered in order to explain intraspecific variability in cooperative behaviors, and also that this feedback between evolution and ecology can critically affect the demographic fate

  1. feedback between population and evolutionary dynamics determines the fate of social microbial populations.

    Directory of Open Access Journals (Sweden)

    Alvaro Sanchez

    Full Text Available The evolutionary spread of cheater strategies can destabilize populations engaging in social cooperative behaviors, thus demonstrating that evolutionary changes can have profound implications for population dynamics. At the same time, the relative fitness of cooperative traits often depends upon population density, thus leading to the potential for bi-directional coupling between population density and the evolution of a cooperative trait. Despite the potential importance of these eco-evolutionary feedback loops in social species, they have not yet been demonstrated experimentally and their ecological implications are poorly understood. Here, we demonstrate the presence of a strong feedback loop between population dynamics and the evolutionary dynamics of a social microbial gene, SUC2, in laboratory yeast populations whose cooperative growth is mediated by the SUC2 gene. We directly visualize eco-evolutionary trajectories of hundreds of populations over 50-100 generations, allowing us to characterize the phase space describing the interplay of evolution and ecology in this system. Small populations collapse despite continual evolution towards increased cooperative allele frequencies; large populations with a sufficient number of cooperators "spiral" to a stable state of coexistence between cooperator and cheater strategies. The presence of cheaters does not significantly affect the equilibrium population density, but it does reduce the resilience of the population as well as its ability to adapt to a rapidly deteriorating environment. Our results demonstrate the potential ecological importance of coupling between evolutionary dynamics and the population dynamics of cooperatively growing organisms, particularly in microbes. Our study suggests that this interaction may need to be considered in order to explain intraspecific variability in cooperative behaviors, and also that this feedback between evolution and ecology can critically affect the

  2. Rapid evolution leads to differential population dynamics and top-down control in resurrected Daphnia populations.

    Science.gov (United States)

    Goitom, Eyerusalem; Kilsdonk, Laurens J; Brans, Kristien; Jansen, Mieke; Lemmens, Pieter; De Meester, Luc

    2018-01-01

    There is growing evidence of rapid genetic adaptation of natural populations to environmental change, opening the perspective that evolutionary trait change may subsequently impact ecological processes such as population dynamics, community composition, and ecosystem functioning. To study such eco-evolutionary feedbacks in natural populations, however, requires samples across time. Here, we capitalize on a resurrection ecology study that documented rapid and adaptive evolution in a natural population of the water flea Daphnia magna in response to strong changes in predation pressure by fish, and carry out a follow-up mesocosm experiment to test whether the observed genetic changes influence population dynamics and top-down control of phytoplankton. We inoculated populations of the water flea D. magna derived from three time periods of the same natural population known to have genetically adapted to changes in predation pressure in replicate mesocosms and monitored both Daphnia population densities and phytoplankton biomass in the presence and absence of fish. Our results revealed differences in population dynamics and top-down control of algae between mesocosms harboring populations from the time period before, during, and after a peak in fish predation pressure caused by human fish stocking. The differences, however, deviated from our a priori expectations. An S-map approach on time series revealed that the interactions between adults and juveniles strongly impacted the dynamics of populations and their top-down control on algae in the mesocosms, and that the strength of these interactions was modulated by rapid evolution as it occurred in nature. Our study provides an example of an evolutionary response that fundamentally alters the processes structuring population dynamics and impacts ecosystem features.

  3. Population and evolutionary dynamics in spatially structured seasonally varying environments.

    Science.gov (United States)

    Reid, Jane M; Travis, Justin M J; Daunt, Francis; Burthe, Sarah J; Wanless, Sarah; Dytham, Calvin

    2018-03-25

    Increasingly imperative objectives in ecology are to understand and forecast population dynamic and evolutionary responses to seasonal environmental variation and change. Such population and evolutionary dynamics result from immediate and lagged responses of all key life-history traits, and resulting demographic rates that affect population growth rate, to seasonal environmental conditions and population density. However, existing population dynamic and eco-evolutionary theory and models have not yet fully encompassed within-individual and among-individual variation, covariation, structure and heterogeneity, and ongoing evolution, in a critical life-history trait that allows individuals to respond to seasonal environmental conditions: seasonal migration. Meanwhile, empirical studies aided by new animal-tracking technologies are increasingly demonstrating substantial within-population variation in the occurrence and form of migration versus year-round residence, generating diverse forms of 'partial migration' spanning diverse species, habitats and spatial scales. Such partially migratory systems form a continuum between the extreme scenarios of full migration and full year-round residence, and are commonplace in nature. Here, we first review basic scenarios of partial migration and associated models designed to identify conditions that facilitate the maintenance of migratory polymorphism. We highlight that such models have been fundamental to the development of partial migration theory, but are spatially and demographically simplistic compared to the rich bodies of population dynamic theory and models that consider spatially structured populations with dispersal but no migration, or consider populations experiencing strong seasonality and full obligate migration. Second, to provide an overarching conceptual framework for spatio-temporal population dynamics, we define a 'partially migratory meta-population' system as a spatially structured set of locations that can

  4. An age-structured population balance model for microbial dynamics

    Directory of Open Access Journals (Sweden)

    Duarte M.V.E.

    2003-01-01

    Full Text Available This work presents an age-structured population balance model (ASPBM for a bioprocess in a continuous stirred-tank fermentor. It relates the macroscopic properties and dynamic behavior of biomass to the operational parameters and microscopic properties of cells. Population dynamics is governed by two time- and age-dependent density functions for living and dead cells, accounting for the influence of substrate and dissolved oxygen concentrations on cell division, aging and death processes. The ASPBM described biomass and substrate oscillations in aerobic continuous cultures as experimentally observed. It is noteworthy that a small data set consisting of nonsegregated measurements was sufficient to adjust a complex segregated mathematical model.

  5. Estimating spatio-temporal dynamics of size-structured populations

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Thygesen, Uffe Høgsbro; Andersen, Ken Haste

    2014-01-01

    with simple stock dynamics, to estimate simultaneously how size distributions and spatial distributions develop in time. We demonstrate the method for a cod population sampled by trawl surveys. Particular attention is paid to correlation between size classes within each trawl haul due to clustering...... of individuals with similar size. The model estimates growth, mortality and reproduction, after which any aspect of size-structure, spatio-temporal population dynamics, as well as the sampling process can be probed. This is illustrated by two applications: 1) tracking the spatial movements of a single cohort...

  6. Network evolution induced by the dynamical rules of two populations

    International Nuclear Information System (INIS)

    Platini, Thierry; Zia, R K P

    2010-01-01

    We study the dynamical properties of a finite dynamical network composed of two interacting populations, namely extrovert (a) and introvert (b). In our model, each group is characterized by its size (N a and N b ) and preferred degree (κ a and κ b a ). The network dynamics is governed by the competing microscopic rules of each population that consist of the creation and destruction of links. Starting from an unconnected network, we give a detailed analysis of the mean field approach which is compared to Monte Carlo simulation data. The time evolution of the restricted degrees (k bb ) and (k ab ) presents three time regimes and a non-monotonic behavior well captured by our theory. Surprisingly, when the population sizes are equal N a = N b , the ratio of the restricted degree θ 0 = (k ab )/(k bb ) appears to be an integer in the asymptotic limits of the three time regimes. For early times (defined by t 1 = κ b ) the total number of links presents a linear evolution, where the two populations are indistinguishable and where θ 0 = 1. Interestingly, in the intermediate time regime (defined for t 1 2 ∝κ a and for which θ 0 = 5), the system reaches a transient stationary state, where the number of contacts among introverts remains constant while the number of connections increases linearly in the extrovert population. Finally, due to the competing dynamics, the network presents a frustrated stationary state characterized by a ratio θ 0 = 3

  7. Social Information Links Individual Behavior to Population and Community Dynamics.

    Science.gov (United States)

    Gil, Michael A; Hein, Andrew M; Spiegel, Orr; Baskett, Marissa L; Sih, Andrew

    2018-05-07

    When individual animals make decisions, they routinely use information produced intentionally or unintentionally by other individuals. Despite its prevalence and established fitness consequences, the effects of such social information on ecological dynamics remain poorly understood. Here, we synthesize results from ecology, evolutionary biology, and animal behavior to show how the use of social information can profoundly influence the dynamics of populations and communities. We combine recent theoretical and empirical results and introduce simple population models to illustrate how social information use can drive positive density-dependent growth of populations and communities (Allee effects). Furthermore, social information can shift the nature and strength of species interactions, change the outcome of competition, and potentially increase extinction risk in harvested populations and communities. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Population dynamics of active and total ciliate populations in arable soil amended with wheat

    DEFF Research Database (Denmark)

    Ekelund, F.; Frederiksen, Helle B.; Ronn, R.

    2002-01-01

    of the population may be encysted. The factors governing the dynamics of active and encysted cells in the soil are not well understood. Our objective was to determine the dynamics of active and encysted populations of ciliates during the decomposition of freshly added organic material. We monitored, in soil...... microcosms, the active and total populations of ciliates, their potential prey (bacteria and small protozoa), their potential competitors (amoebae, flagellates, and nematodes), and their potential predators (nematodes). We sampled with short time intervals (2 to 6 days) and generated a data set, suitable...

  9. Prevalence of depression among mothers of young children in Honduras.

    Science.gov (United States)

    Wulsin, Lawson; Somoza, Eugene; Heck, Jeffery; Bauer, Leah

    2010-01-01

    Maternal depression is a substantial problem that has negative consequences on the health of both mother and child. Little research has been done on the prevalence of maternal depression in the developing world. This study aims to estimate the prevalence of current depression among mothers in Honduras and identify demographic predictors of depression in this sample. A modified Spanish version of the PHQ-9 and a demographic questionnaire were administered by trained interviewers to 415 rural and urban women aged 15-66 who had children between 1 and 10 years old. Prevalence of current major depressive syndrome was 17.6%. Mild depressive symptoms were detected in 52% of the sample. The estimated prevalence of current major depressive syndrome in the urban sample (19%) was not significantly greater than in the rural sample (16%, p = 0.49). None of the demographic variables measured, including age, number of children, or marital status predicted major depression in this sample. Maternal depression occurred at a high rate in this sample of Honduran women. The estimated prevalence rates in this study are similar to rates of maternal depression in studies of mothers in other Latin American countries, as well as in samples of mothers on Medicaid in the United States. Further study is needed to confirm and extend these findings, and to identify predictors of maternal depression in this population.

  10. A general modeling framework for describing spatially structured population dynamics

    Science.gov (United States)

    Sample, Christine; Fryxell, John; Bieri, Joanna; Federico, Paula; Earl, Julia; Wiederholt, Ruscena; Mattsson, Brady; Flockhart, Tyler; Nicol, Sam; Diffendorfer, James E.; Thogmartin, Wayne E.; Erickson, Richard A.; Norris, D. Ryan

    2017-01-01

    Variation in movement across time and space fundamentally shapes the abundance and distribution of populations. Although a variety of approaches model structured population dynamics, they are limited to specific types of spatially structured populations and lack a unifying framework. Here, we propose a unified network-based framework sufficiently novel in its flexibility to capture a wide variety of spatiotemporal processes including metapopulations and a range of migratory patterns. It can accommodate different kinds of age structures, forms of population growth, dispersal, nomadism and migration, and alternative life-history strategies. Our objective was to link three general elements common to all spatially structured populations (space, time and movement) under a single mathematical framework. To do this, we adopt a network modeling approach. The spatial structure of a population is represented by a weighted and directed network. Each node and each edge has a set of attributes which vary through time. The dynamics of our network-based population is modeled with discrete time steps. Using both theoretical and real-world examples, we show how common elements recur across species with disparate movement strategies and how they can be combined under a unified mathematical framework. We illustrate how metapopulations, various migratory patterns, and nomadism can be represented with this modeling approach. We also apply our network-based framework to four organisms spanning a wide range of life histories, movement patterns, and carrying capacities. General computer code to implement our framework is provided, which can be applied to almost any spatially structured population. This framework contributes to our theoretical understanding of population dynamics and has practical management applications, including understanding the impact of perturbations on population size, distribution, and movement patterns. By working within a common framework, there is less chance

  11. Stochastic population dynamics of a montane ground-dwelling squirrel.

    Directory of Open Access Journals (Sweden)

    Jeffrey A Hostetler

    Full Text Available Understanding the causes and consequences of population fluctuations is a central goal of ecology. We used demographic data from a long-term (1990-2008 study and matrix population models to investigate factors and processes influencing the dynamics and persistence of a golden-mantled ground squirrel (Callospermophilus lateralis population, inhabiting a dynamic subalpine habitat in Colorado, USA. The overall deterministic population growth rate λ was 0.94±SE 0.05 but it varied widely over time, ranging from 0.45±0.09 in 2006 to 1.50±0.12 in 2003, and was below replacement (λ<1 for 9 out of 18 years. The stochastic population growth rate λ(s was 0.92, suggesting a declining population; however, the 95% CI on λ(s included 1.0 (0.52-1.60. Stochastic elasticity analysis showed that survival of adult females, followed by survival of juvenile females and litter size, were potentially the most influential vital rates; analysis of life table response experiments revealed that the same three life history variables made the largest contributions to year-to year changes in λ. Population viability analysis revealed that, when the influences of density dependence and immigration were not considered, the population had a high (close to 1.0 in 50 years probability of extinction. However, probability of extinction declined to as low as zero when density dependence and immigration were considered. Destabilizing effects of stochastic forces were counteracted by regulating effects of density dependence and rescue effects of immigration, which allowed our study population to bounce back from low densities and prevented extinction. These results suggest that dynamics and persistence of our study population are determined synergistically by density-dependence, stochastic forces, and immigration.

  12. SIR dynamics in structured populations with heterogeneous connectivity

    OpenAIRE

    Volz, Erik

    2005-01-01

    Most epidemic models assume equal mixing among members of a population. An alternative approach is to model a population as random network in which individuals may have heterogeneous connectivity. This paper builds on previous research by describing the exact dynamical behavior of epidemics as they occur in random networks. A system of nonlinear differential equations is presented which describes the behavior of epidemics spreading through random networks with arbitrary degree distributions. ...

  13. Estimating Traveler Populations at Airport and Cruise Terminals for Population Distribution and Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Jochem, Warren C [ORNL; Sims, Kelly M [ORNL; Bright, Eddie A [ORNL; Urban, Marie L [ORNL; Rose, Amy N [ORNL; Coleman, Phil R [ORNL; Bhaduri, Budhendra L [ORNL

    2013-01-01

    In recent years, uses of high-resolution population distribution databases are increasing steadily for environmental, socioeconomic, public health, and disaster-related research and operations. With the development of daytime population distribution, temporal resolution of such databases has been improved. However, the lack of incorporation of transitional population, namely business and leisure travelers, leaves a significant population unaccounted for within the critical infrastructure networks, such as at transportation hubs. This paper presents two general methodologies for estimating passenger populations in airport and cruise port terminals at a high temporal resolution which can be incorporated into existing population distribution models. The methodologies are geographically scalable and are based on, and demonstrate how, two different transportation hubs with disparate temporal population dynamics can be modeled utilizing publicly available databases including novel data sources of flight activity from the Internet which are updated in near-real time. The airport population estimation model shows great potential for rapid implementation for a large collection of airports on a national scale, and the results suggest reasonable accuracy in the estimated passenger traffic. By incorporating population dynamics at high temporal resolutions into population distribution models, we hope to improve the estimates of populations exposed to or at risk to disasters, thereby improving emergency planning and response, and leading to more informed policy decisions.

  14. A four-year surveillance program for detection of Plasmodium falciparum chloroquine resistance in Honduras

    Directory of Open Access Journals (Sweden)

    Gustavo A Fontecha

    2014-07-01

    Full Text Available Countries could use the monitoring of drug resistance in malaria parasites as an effective early warning system to develop the timely response mechanisms that are required to avert the further spread of malaria. Drug resistance surveillance is essential in areas where no drug resistance has been reported, especially if neighbouring countries have previously reported resistance. Here, we present the results of a four-year surveillance program based on the sequencing of the pfcrt gene of Plasmodium falciparum populations from endemic areas of Honduras. All isolates were susceptible to chloroquine, as revealed by the pfcrt “CVMNK” genotype in codons 72-76.

  15. Short-term service trips and the interprofessional team: a perspective from Honduras.

    Science.gov (United States)

    VanderWielen, Lynn M; Halder, Gabriela E; Enurah, Alexander S; Pearson, Catherine; Stevens, Michael P; Crossman, Steven H

    2015-03-01

    Short-term service trips from the USA annually spend over $250 million dollars to provide healthcare to individuals in developing nations. These trips often uniquely define goals as related to changes in the host population and overlook the valuable benefits potentially incurred by the trip volunteers. The Honduras Outreach Medical Brigada Relief Effort utilizes an interprofessional team approach to develop the dual goals of improving health and quality of life in host communities and improving interprofessional teamwork values and skills among participants. This article outlines details of this program, describes on-going evaluation work and discusses the interprofessional implications from this project.

  16. A four-year surveillance program for detection of Plasmodium falciparum chloroquine resistance in Honduras.

    Science.gov (United States)

    Fontecha, Gustavo A; Sanchez, Ana L; Mendoza, Meisy; Banegas, Engels; Mejía-Torres, Rosa E

    2014-07-01

    Countries could use the monitoring of drug resistance in malaria parasites as an effective early warning system to develop the timely response mechanisms that are required to avert the further spread of malaria. Drug resistance surveillance is essential in areas where no drug resistance has been reported, especially if neighbouring countries have previously reported resistance. Here, we present the results of a four-year surveillance program based on the sequencing of the pfcrt gene of Plasmodium falciparum populations from endemic areas of Honduras. All isolates were susceptible to chloroquine, as revealed by the pfcrt "CVMNK" genotype in codons 72-76.

  17. 78 FR 20123 - Extension of the Designation of Honduras for Temporary Protected Status

    Science.gov (United States)

    2013-04-03

    ... Docket No. USCIS-2012-0016] RIN 1615-ZB18 Extension of the Designation of Honduras for Temporary... the designation of Honduras for Temporary Protected Status (TPS) for 18 months from July 6, 2013... Honduras that prompted the TPS designation continue to be met. There continues to be a substantial, but...

  18. Stochastic population dynamics in populations of western terrestrial garter snakes with divergent life histories.

    Science.gov (United States)

    Miller, David A; Clark, William R; Arnold, Stevan J; Bronikowski, Anne M

    2011-08-01

    Comparative evaluations of population dynamics in species with temporal and spatial variation in life-history traits are rare because they require long-term demographic time series from multiple populations. We present such an analysis using demographic data collected during the interval 1978-1996 for six populations of western terrestrial garter snakes (Thamnophis elegans) from two evolutionarily divergent ecotypes. Three replicate populations from a slow-living ecotype, found in mountain meadows of northeastern California, were characterized by individuals that develop slowly, mature late, reproduce infrequently with small reproductive effort, and live longer than individuals of three populations of a fast-living ecotype found at lakeshore locales. We constructed matrix population models for each of the populations based on 8-13 years of data per population and analyzed both deterministic dynamics based on mean annual vital rates and stochastic dynamics incorporating annual variation in vital rates. (1) Contributions of highly variable vital rates to fitness (lambda(s)) were buffered against the negative effects of stochastic variation, and this relationship was consistent with differences between the meadow (M-slow) and lakeshore (L-fast) ecotypes. (2) Annual variation in the proportion of gravid females had the greatest negative effect among all vital rates on lambda(s). The magnitude of variation in the proportion of gravid females and its effect on lambda(s) was greater in M-slow than L-fast populations. (3) Variation in the proportion of gravid females, in turn, depended on annual variation in prey availability, and its effect on lambda(s) was 4 23 times greater in M-slow than L-fast populations. In addition to differences in stochastic dynamics between ecotypes, we also found higher mean mortality rates across all age classes in the L-fast populations. Our results suggest that both deterministic and stochastic selective forces have affected the evolution of

  19. Population dynamics of light-limited phytoplankton : Microcosm experiments

    NARCIS (Netherlands)

    Huisman, Jef

    This paper investigates the extent to which the predictions of an elementary model for light-limited growth are matched by laboratory experiments with light-limited phytoplankton. The model and experiments link the population dynamics of phytoplankton species with changes in the light gradient

  20. Distribution and population dynamics of Rhizobium sp. introduced into soil

    NARCIS (Netherlands)

    Postma, J.

    1989-01-01

    In this thesis the population dynamics of bacteria introduced into soil was studied. In the introduction, the existence of microhabitats favourable for the survival of indigenous bacteria is discussed. Knowledge about the distribution of introduced bacteria over

  1. seasonal population dynamics of rodents of mount chilalo, arsi ...

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    ABSTRACT: A study on seasonal population dynamics of rodents was carried out on Mount. Chilalo from .... vegetation growth, availability of food and water, and ... vegetation (3,300–4,200 masl) (Alemayehu. Mengistu, 1975; APEDO and ABRDP, 2004). The mountain is one of the Afrotropical biodiversity hotspots areas.

  2. Population dynamics of soil microbes and diversity of Bacillus ...

    African Journals Online (AJOL)

    ONOS

    2010-01-25

    Jan 25, 2010 ... Population dynamics of soil microbes and diversity of ... 25.78, 25.78, 86.26, 24.73, 68.0, 26.8 and 26.8 kDa proteins and equivalent to Cyt, Cry5 and Cry2 toxins ..... Molecular weight (kDa) of protein fractions of the BT isolates.

  3. Population dynamics of the invasive fish, Gambusia affinis , in ...

    African Journals Online (AJOL)

    Repeated-measures ANOVA analyses on the catch per unit effort (CPUE) of G. affinis between sampling events and dams revealed significant differences in population dynamics among dams, although an overall trend of rapid increase followed by plateau in summer, with a rapid decline in winter was seen in most dams.

  4. Individual based model of slug population and spatial dynamics

    NARCIS (Netherlands)

    Choi, Y.H.; Bohan, D.A.; Potting, R.P.J.; Semenov, M.A.; Glen, D.M.

    2006-01-01

    The slug, Deroceras reticulatum, is one of the most important pests of agricultural and horticultural crops in UK and Europe. In this paper, a spatially explicit individual based model (IbM) is developed to study the dynamics of a population of D. reticulatum. The IbM establishes a virtual field

  5. Network evolution induced by the dynamical rules of two populations

    Science.gov (United States)

    Platini, Thierry; Zia, R. K. P.

    2010-10-01

    We study the dynamical properties of a finite dynamical network composed of two interacting populations, namely extrovert (a) and introvert (b). In our model, each group is characterized by its size (Na and Nb) and preferred degree (κa and \\kappa_b\\ll \\kappa_a ). The network dynamics is governed by the competing microscopic rules of each population that consist of the creation and destruction of links. Starting from an unconnected network, we give a detailed analysis of the mean field approach which is compared to Monte Carlo simulation data. The time evolution of the restricted degrees langkbbrang and langkabrang presents three time regimes and a non-monotonic behavior well captured by our theory. Surprisingly, when the population sizes are equal Na = Nb, the ratio of the restricted degree θ0 = langkabrang/langkbbrang appears to be an integer in the asymptotic limits of the three time regimes. For early times (defined by t introverts remains constant while the number of connections increases linearly in the extrovert population. Finally, due to the competing dynamics, the network presents a frustrated stationary state characterized by a ratio θ0 = 3.

  6. An individual-based model of Zebrafish population dynamics accounting for energy dynamics

    DEFF Research Database (Denmark)

    Beaudouin, Remy; Goussen, Benoit; Piccini, Benjamin

    2015-01-01

    Developing population dynamics models for zebrafish is crucial in order to extrapolate from toxicity data measured at the organism level to biological levels relevant to support and enhance ecological risk assessment. To achieve this, a dynamic energy budget for individual zebrafish (DEB model...

  7. [Population dynamics and armed violence in Colombia, 1985-2010].

    Science.gov (United States)

    Salaya, Hernán Eduardo; Rodríguez, Jesús

    2014-09-01

    Describe changes in the population structure of Colombia's municipalities in relation to internal displacement in response to armed violence. A descriptive ecological study was carried out. Secondary sources were consulted, taken from the Consolidated Registry of Displaced Population and from the National Administrative Department of Statistics, to calculate expulsion and reception rates for population displaced by violence from 2002 to 2010. Based on these rates, four groups were created of municipalities in the extreme quartile for each rate during the entire period, which were classified as high expulsion, low expulsion, high reception, and low reception. Subsequently, population pyramids and structure indicators were constructed for each group of municipalities for two comparative reference years (1985 and 2010). Municipalities with high expulsion or reception rates experienced a slower epidemiological transition, with lower mean ages and aging indices. The high expulsion group had the least regression, based on the Sundbärg index. In the high reception group, the masculinity ratio decreased the most, especially among the economically active population, and it had the highest population growth. Population dynamics in Colombia have been affected by armed violence and changes in these dynamics are not uniform across the country, leading to important social, economic, and cultural consequences. This study is useful for decision-making and public policy making.

  8. Bridging the Timescales of Single-Cell and Population Dynamics

    Science.gov (United States)

    Jafarpour, Farshid; Wright, Charles S.; Gudjonson, Herman; Riebling, Jedidiah; Dawson, Emma; Lo, Klevin; Fiebig, Aretha; Crosson, Sean; Dinner, Aaron R.; Iyer-Biswas, Srividya

    2018-04-01

    How are granular details of stochastic growth and division of individual cells reflected in smooth deterministic growth of population numbers? We provide an integrated, multiscale perspective of microbial growth dynamics by formulating a data-validated theoretical framework that accounts for observables at both single-cell and population scales. We derive exact analytical complete time-dependent solutions to cell-age distributions and population growth rates as functionals of the underlying interdivision time distributions, for symmetric and asymmetric cell division. These results provide insights into the surprising implications of stochastic single-cell dynamics for population growth. Using our results for asymmetric division, we deduce the time to transition from the reproductively quiescent (swarmer) to the replication-competent (stalked) stage of the Caulobacter crescentus life cycle. Remarkably, population numbers can spontaneously oscillate with time. We elucidate the physics leading to these population oscillations. For C. crescentus cells, we show that a simple measurement of the population growth rate, for a given growth condition, is sufficient to characterize the condition-specific cellular unit of time and, thus, yields the mean (single-cell) growth and division timescales, fluctuations in cell division times, the cell-age distribution, and the quiescence timescale.

  9. Transmitted drug resistance and type of infection in newly diagnosed HIV-1 individuals in Honduras.

    Science.gov (United States)

    Murillo, Wendy; Paz-Bailey, Gabriela; Morales, Sonia; Monterroso, Edgar; Paredes, Mayte; Dobbs, Trudy; Parekh, Bharat S; Albert, Jan; Rivera, Ivette Lorenzana de

    2010-12-01

    Transmitted drug resistance (TDR) reduces the efficacy of antiretroviral treatment and is a public health concern. To gain insight in the epidemiology of TDR in Honduras by evaluating the amount of TDR in a representative sample of newly diagnosed individuals and by determining whether these are recent or established infections. Two hundred treatment-naïve, newly diagnosed HIV-positive individuals representing different population groups (general population, Garifunas ethnic group, female sex workers and men who have sex with men) and different geographic regions were enrolled during April 2004-April 2007. The HIV-1 pol gene was sequenced to identify drug-resistant mutations and TDR was scored as recommended by the WHO. Specimens were classified as recent or established infections using the BED assay. Among 200 samples analyzed from Honduran patients the prevalence of TDR was 7% (95% CI: 3.9-11.5%), 5% for non-nucleoside reverse transcriptase inhibitors (NNRTIs), 3% for nucleoside reverse transcriptase inhibitors (NRTIs) and 0.5% for protease inhibitors (PIs). Testing of these samples with the BED assay revealed that 12% of the specimens were associated with recent infections. TDR was significantly more common in specimens with recent infection (21%) than established infection (5%) (p=0.016). The prevalence of TDR in Honduras was moderate (7%). The percentage of specimens who were recently infected was low (12%), suggesting that late HIV diagnosis is common. The TDR prevalence was higher in recent than in established infections, which may indicate that TDR is increasing over time. The higher prevalence of NNRTI and NRTI mutations as compared to PI mutations is probably due to a broader and longer use of these drugs in Honduras. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Nonequilibrium population dynamics of phenotype conversion of cancer cells.

    Directory of Open Access Journals (Sweden)

    Joseph Xu Zhou

    Full Text Available Tumorigenesis is a dynamic biological process that involves distinct cancer cell subpopulations proliferating at different rates and interconverting between them. In this paper we proposed a mathematical framework of population dynamics that considers both distinctive growth rates and intercellular transitions between cancer cell populations. Our mathematical framework showed that both growth and transition influence the ratio of cancer cell subpopulations but the latter is more significant. We derived the condition that different cancer cell types can maintain distinctive subpopulations and we also explain why there always exists a stable fixed ratio after cell sorting based on putative surface markers. The cell fraction ratio can be shifted by changing either the growth rates of the subpopulations (Darwinism selection or by environment-instructed transitions (Lamarckism induction. This insight can help us to understand the dynamics of the heterogeneity of cancer cells and lead us to new strategies to overcome cancer drug resistance.

  11. Central-marginal population dynamics in species invasions

    Directory of Open Access Journals (Sweden)

    Qinfeng eGuo

    2014-06-01

    Full Text Available The species’ range limits and associated central-marginal (C-M; i.e., from species range center to margin population dynamics continue to draw increasing attention because of their importance for current emerging issues such as biotic invasions and epidemic diseases under global change. Previous studies have mainly focused on species borders and C-M process in natural settings for native species. More recently, growing efforts are devoted to examine the C-M patterns and process for invasive species partly due to their relatively short history, highly dynamic populations, and management implications. Here I examine recent findings and information gaps related to (1 the C-M population dynamics linked to species invasions, and (2 the possible effects of climate change and land use on the C-M patterns and processes. Unlike most native species that are relatively stable (some even having contracting populations or ranges, many invasive species are still spreading fast and form new distribution or abundance centers. Because of the strong nonlinearity of population demographic or vital rates (i.e. birth, death, immigration and emigration across the C-M gradients and the increased complexity of species ranges due to habitat fragmentation, multiple introductions, range-wide C-M comparisons and simulation involving multiple vital rates are needed in the future.

  12. Rethinking the logistic approach for population dynamics of mutualistic interactions.

    Science.gov (United States)

    García-Algarra, Javier; Galeano, Javier; Pastor, Juan Manuel; Iriondo, José María; Ramasco, José J

    2014-12-21

    Mutualistic communities have an internal structure that makes them resilient to external perturbations. Late research has focused on their stability and the topology of the relations between the different organisms to explain the reasons of the system robustness. Much less attention has been invested in analyzing the systems dynamics. The main population models in use are modifications of the r-K formulation of logistic equation with additional terms to account for the benefits produced by the interspecific interactions. These models have shortcomings as the so-called r-K formulation diverges under some conditions. In this work, we introduce a model for population dynamics under mutualism that preserves the original logistic formulation. It is mathematically simpler than the widely used type II models, although it shows similar complexity in terms of fixed points and stability of the dynamics. We perform an analytical stability analysis and numerical simulations to study the model behavior in general interaction scenarios including tests of the resilience of its dynamics under external perturbations. Despite its simplicity, our results indicate that the model dynamics shows an important richness that can be used to gain further insights in the dynamics of mutualistic communities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Aspiration dynamics of multi-player games in finite populations.

    Science.gov (United States)

    Du, Jinming; Wu, Bin; Altrock, Philipp M; Wang, Long

    2014-05-06

    On studying strategy update rules in the framework of evolutionary game theory, one can differentiate between imitation processes and aspiration-driven dynamics. In the former case, individuals imitate the strategy of a more successful peer. In the latter case, individuals adjust their strategies based on a comparison of their pay-offs from the evolutionary game to a value they aspire, called the level of aspiration. Unlike imitation processes of pairwise comparison, aspiration-driven updates do not require additional information about the strategic environment and can thus be interpreted as being more spontaneous. Recent work has mainly focused on understanding how aspiration dynamics alter the evolutionary outcome in structured populations. However, the baseline case for understanding strategy selection is the well-mixed population case, which is still lacking sufficient understanding. We explore how aspiration-driven strategy-update dynamics under imperfect rationality influence the average abundance of a strategy in multi-player evolutionary games with two strategies. We analytically derive a condition under which a strategy is more abundant than the other in the weak selection limiting case. This approach has a long-standing history in evolutionary games and is mostly applied for its mathematical approachability. Hence, we also explore strong selection numerically, which shows that our weak selection condition is a robust predictor of the average abundance of a strategy. The condition turns out to differ from that of a wide class of imitation dynamics, as long as the game is not dyadic. Therefore, a strategy favoured under imitation dynamics can be disfavoured under aspiration dynamics. This does not require any population structure, and thus highlights the intrinsic difference between imitation and aspiration dynamics.

  14. An age structured model for obesity prevalence dynamics in populations

    Directory of Open Access Journals (Sweden)

    Gilberto González Parra

    2010-08-01

    Full Text Available Objective. Modeling the correlation of the development of obesity in a population with age and time and predict the dynamics of the correlation of the development of obesity in a population with age and time under different scenarios in Valencia (Spain. Materials and methods. An age structured mathematical model is used to describe the future dynamics of obesity prevalence for different ages in human population with excess weight. Simulation of the model with parameters estimated using the Health Survey of the Region of Valencia 2000 (4.319 interviews and Health Survey of the Region of Valencia 2005 (4.012 interviews. The model considers only overweight and obese populations since these subpopulations are the most relevant on obesity health concern. Results. The model allows predicting and studying the prevalence of obesity for each age. Results showed an increasing trend of obesity in the following years in well accordance with the trend observed in several countries. Conclusions. Based on the numerical simulations it is possible to conclude that the age structured mathematical model is suitable to forecast the obesity epidemic in each age group in different countries. Additionally, this type of models may be applied to study other characteristics of other populations such animal populations.

  15. Modeling structured population dynamics using data from unmarked individuals

    Science.gov (United States)

    Grant, Evan H. Campbell; Zipkin, Elise; Thorson, James T.; See, Kevin; Lynch, Heather J.; Kanno, Yoichiro; Chandler, Richard; Letcher, Benjamin H.; Royle, J. Andrew

    2014-01-01

    The study of population dynamics requires unbiased, precise estimates of abundance and vital rates that account for the demographic structure inherent in all wildlife and plant populations. Traditionally, these estimates have only been available through approaches that rely on intensive mark–recapture data. We extended recently developed N-mixture models to demonstrate how demographic parameters and abundance can be estimated for structured populations using only stage-structured count data. Our modeling framework can be used to make reliable inferences on abundance as well as recruitment, immigration, stage-specific survival, and detection rates during sampling. We present a range of simulations to illustrate the data requirements, including the number of years and locations necessary for accurate and precise parameter estimates. We apply our modeling framework to a population of northern dusky salamanders (Desmognathus fuscus) in the mid-Atlantic region (USA) and find that the population is unexpectedly declining. Our approach represents a valuable advance in the estimation of population dynamics using multistate data from unmarked individuals and should additionally be useful in the development of integrated models that combine data from intensive (e.g., mark–recapture) and extensive (e.g., counts) data sources.

  16. Molecular diversity of Mycobacterium tuberculosis isolates from patients with tuberculosis in Honduras

    Directory of Open Access Journals (Sweden)

    Ghebremichael Solomon

    2010-08-01

    Full Text Available Abstract Background Tuberculosis persists as a public health problem in Honduras. A better knowledge of the molecular characteristics of Mycobacterium tuberculosis strains will contribute to understand the transmission dynamics of the disease within the country. The aim of this study was to provide an insight of the genetic biodiversity of M. tuberculosis clinical isolates collected in Honduras between 1994 and 2002. Genotyping was performed using spoligotyping and RFLP. The spoligotypes obtained were compared with the SITVIT2 proprietary database of the Pasteur Institute of Guadeloupe. Results Spoligotyping grouped 84% of the isolates into 27 clusters (2 to 43 strains per cluster. Of the 44 shared international types (SITs identified among the Honduran stains, 8 SITs were newly identified either within the present study or after match with an orphan type previously identified in the SITVIT2 database. In addition, 16 patterns corresponded to orphan, previously unreported isolates. The Latin American Mediterranean (LAM lineage was the most common in this study; 55% of the strains belonged to this family. Other genotypes found were Haarlem (16%, T (16%, X-clade (6%, Unknown signature (5% and S (1%. Only one Beijing strain was identified (0.5%. We observed a high degree of diversity after characterizing the 43 isolates belonging to the main spoligotyping cluster (SIT 33, LAM3 with IS6110-RFLP. A total of 35 different RFLP-fingerprints were detected, of which 6 patterns corresponded to the same number of clusters comprising 14 strains. Conclusions The findings obtained in this study show that tuberculosis transmission in Honduras is due to modern M. tuberculosis lineages with high level of biodiversity.

  17. Molecular diversity of Mycobacterium tuberculosis isolates from patients with tuberculosis in Honduras

    Science.gov (United States)

    2010-01-01

    Background Tuberculosis persists as a public health problem in Honduras. A better knowledge of the molecular characteristics of Mycobacterium tuberculosis strains will contribute to understand the transmission dynamics of the disease within the country. The aim of this study was to provide an insight of the genetic biodiversity of M. tuberculosis clinical isolates collected in Honduras between 1994 and 2002. Genotyping was performed using spoligotyping and RFLP. The spoligotypes obtained were compared with the SITVIT2 proprietary database of the Pasteur Institute of Guadeloupe. Results Spoligotyping grouped 84% of the isolates into 27 clusters (2 to 43 strains per cluster). Of the 44 shared international types (SITs) identified among the Honduran stains, 8 SITs were newly identified either within the present study or after match with an orphan type previously identified in the SITVIT2 database. In addition, 16 patterns corresponded to orphan, previously unreported isolates. The Latin American Mediterranean (LAM) lineage was the most common in this study; 55% of the strains belonged to this family. Other genotypes found were Haarlem (16%), T (16%), X-clade (6%), Unknown signature (5%) and S (1%). Only one Beijing strain was identified (0.5%). We observed a high degree of diversity after characterizing the 43 isolates belonging to the main spoligotyping cluster (SIT 33, LAM3) with IS6110-RFLP. A total of 35 different RFLP-fingerprints were detected, of which 6 patterns corresponded to the same number of clusters comprising 14 strains. Conclusions The findings obtained in this study show that tuberculosis transmission in Honduras is due to modern M. tuberculosis lineages with high level of biodiversity. PMID:20678242

  18. Assessing Knowledge and Perceptions Related to Preventive Methods and Treatment of Malaria in the Local Endemic Area of Trujillo, Honduras.

    Science.gov (United States)

    Campodonico, Joanna; Sevilla-Martir, Javier; Arrizabalaga, Gustavo; Kochhar, Komal

    2015-01-01

    Malaria in Honduras is endemic and accounts for 40% of the total cases in Central America. Our goal was to assess knowledge of preventive methods and current treatment of malaria among the affected community of Trujillo, Honduras. A cross-sectional survey was administered to 71 individuals. Most respondents had a good understanding about common malaria symptoms but not about the complications associated with severe cases. More important, we found that less than 20% of the respondents recognized indoor residual sprays and insecticide-treated nets as effective preventive measures, which are the most efficient preventive methods. Our study highlights the perceptions the people of Trujillo have about malaria. From our observations, we put forward recommendations to implement a comprehensive campaign to educate the Trujillo population about malaria preventive methods and to recruit local and international efforts to distribute insecticide-treated nets.

  19. Efficient characterisation of large deviations using population dynamics

    Science.gov (United States)

    Brewer, Tobias; Clark, Stephen R.; Bradford, Russell; Jack, Robert L.

    2018-05-01

    We consider population dynamics as implemented by the cloning algorithm for analysis of large deviations of time-averaged quantities. We use the simple symmetric exclusion process with periodic boundary conditions as a prototypical example and investigate the convergence of the results with respect to the algorithmic parameters, focussing on the dynamical phase transition between homogeneous and inhomogeneous states, where convergence is relatively difficult to achieve. We discuss how the performance of the algorithm can be optimised, and how it can be efficiently exploited on parallel computing platforms.

  20. Changes in Population Dynamics in Mutualistic versus Pathogenic Viruses

    Directory of Open Access Journals (Sweden)

    Marilyn J. Roossinck

    2011-01-01

    Full Text Available Although generally regarded as pathogens, viruses can also be mutualists. A number of examples of extreme mutualism (i.e., symbiogenesis have been well studied. Other examples of mutualism are less common, but this is likely because viruses have rarely been thought of as having any beneficial effects on their hosts. The effect of mutualism on the population dynamics of viruses is a topic that has not been addressed experimentally. However, the potential for understanding mutualism and how a virus might become a mutualist may be elucidated by understanding these dynamics.

  1. Risk factors associated with the presence and severity of food insecurity in rural Honduras.

    Science.gov (United States)

    Ben-Davies, Maureen E; Kinlaw, Alan; Estrada Del Campo, Yaniré; Bentley, Margaret E; Siega-Riz, Anna Maria

    2014-01-01

    To identify factors associated with the presence and severity of food insecurity among a sample of Honduran caregivers of young children. Cross-sectional study in which the dependent variable, household food insecurity, was measured using a fourteen-item questionnaire developed and validated in a population of similar cultural context. A predictive modelling strategy used backwards elimination in logistic regression and multinomial logit regression models to compute odds ratios and 95% confidence intervals for food insecurity. Rural Honduras in the department of Intibucá, between March and April 2009. Two-hundred and ninety-eight Honduran caregivers of children aged 6-18 months. Ninety-three per cent of households were classified as having some degree of food insecurity (mild, moderate or severe). After controlling for caregiver age and marital status, compared with caregivers with more than primary-school education, those with less than primary-school education had 3·47 (95% CI 1·34, 8·99) times the odds of severe food insecurity and 2·29 (95% CI 1·00, 5·25) times the odds of moderate food insecurity. Our results also found that child anthropometric status was not associated with the presence or severity of food insecurity. These results show that among the sociodemographic factors assessed, food insecurity in rural Honduras is associated with maternal education. Understanding key factors associated with food insecurity that are unique to Honduras can inform the design of interventions to effectively mitigate the negative impact of food insecurity on children.

  2. Obstetric referrals from a rural clinic to a community hospital in Honduras.

    Science.gov (United States)

    Josyula, Srirama; Taylor, Kathryn K; Murphy, Blair M; Rodas, Dairamise; Kamath-Rayne, Beena D

    2015-11-01

    referrals between health care facilities are important in low-resource settings, particularly in maternal and child health, to transfer pregnant patients to the appropriate level of obstetric care. Our aim was to characterise the obstetrical referrals from a rural clinic to a community referral hospital in Honduras, to identify barriers in effective transport/referral, and to describe subsequent patient outcomes. we performed a descriptive retrospective study of patients referred during a 9-month period. We reviewed patient charts to review diagnosis, referral, and treatment times at both sites to understand the continuity of care. ninety-two pregnant patients were referred from the rural clinic to the community hospital. Twenty six pregnant patients (28%) did not have complete and accurate medical records and were excluded from the study. The remaining 66 patients were our study population. Of the 66 patients, 54 (82%) received antenatal care with an average of 5.5±2.4 visits. The most common diagnoses requiring referral were non-reassuring fetal status, hypertensive disorders of pregnancy, and preterm labour. The time spent in the rural clinic until transfer was 7.35±8.60 hours, and transport times were 4.42±1.07 hours. Of the 66 women transferred, 24 (36%) had different primary diagnoses and 16 (24%) had additional diagnoses after evaluation in the community hospital, whereas the remaining 26 (40%) had diagnoses that remained the same. No system was in place to give feedback to the referring clinic doctors regarding their primary diagnoses. our results demonstrate challenges seen in obstetric transport from a rural clinic to a community hospital in Honduras. Further research is needed for reform of emergency obstetric care management, targeting both healthcare personnel and medical referral infrastructure. The example of Honduras can be taken to motivate change in other resource-limited areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Dynamics of a population of oscillatory and excitable elements.

    Science.gov (United States)

    O'Keeffe, Kevin P; Strogatz, Steven H

    2016-06-01

    We analyze a variant of a model proposed by Kuramoto, Shinomoto, and Sakaguchi for a large population of coupled oscillatory and excitable elements. Using the Ott-Antonsen ansatz, we reduce the behavior of the population to a two-dimensional dynamical system with three parameters. We present the stability diagram and calculate several of its bifurcation curves analytically, for both excitatory and inhibitory coupling. Our main result is that when the coupling function is broad, the system can display bistability between steady states of constant high and low activity, whereas when the coupling function is narrow and inhibitory, one of the states in the bistable regime can show persistent pulsations in activity.

  4. Structured population dynamics: continuous size and discontinuous stage structures.

    Science.gov (United States)

    Buffoni, Giuseppe; Pasquali, Sara

    2007-04-01

    A nonlinear stochastic model for the dynamics of a population with either a continuous size structure or a discontinuous stage structure is formulated in the Eulerian formalism. It takes into account dispersion effects due to stochastic variability of the development process of the individuals. The discrete equations of the numerical approximation are derived, and an analysis of the existence and stability of the equilibrium states is performed. An application to a copepod population is illustrated; numerical results of Eulerian and Lagrangian models are compared.

  5. Biology as population dynamics: heuristics for transmission risk.

    Science.gov (United States)

    Keebler, Daniel; Walwyn, David; Welte, Alex

    2013-02-01

    Population-type models, accounting for phenomena such as population lifetimes, mixing patterns, recruitment patterns, genetic evolution and environmental conditions, can be usefully applied to the biology of HIV infection and viral replication. A simple dynamic model can explore the effect of a vaccine-like stimulus on the mortality and infectiousness, which formally looks like fertility, of invading virions; the mortality of freshly infected cells; and the availability of target cells, all of which impact on the probability of infection. Variations on this model could capture the importance of the timing and duration of different key events in viral transmission, and hence be applied to questions of mucosal immunology. The dynamical insights and assumptions of such models are compatible with the continuum of between- and within-individual risks in sexual violence and may be helpful in making sense of the sparse data available on the association between HIV transmission and sexual violence. © 2012 John Wiley & Sons A/S.

  6. Effect of temperature on the population dynamics of Aedes aegypti

    Science.gov (United States)

    Yusoff, Nuraini; Tokachil, Mohd Najir

    2015-10-01

    Aedes aegypti is one of the main vectors in the transmission of dengue fever. Its abundance may cause the spread of the disease to be more intense. In the study of its biological life cycle, temperature was found to increase the development rate of each stage of this species and thus, accelerate the process of the development from egg to adult. In this paper, a Lefkovitch matrix model will be used to study the stage-structured population dynamics of Aedes aegypti. In constructing the transition matrix, temperature will be taken into account. As a case study, temperature recorded at the Subang Meteorological Station for year 2006 until 2010 will be used. Population dynamics of Aedes aegypti at maximum, average and minimum temperature for each year will be simulated and compared. It is expected that the higher the temperature, the faster the mosquito will breed. The result will be compared to the number of dengue fever incidences to see their relationship.

  7. Interacting trophic forcing and the population dynamics of herring

    DEFF Research Database (Denmark)

    Lindegren, Martin; Ostman, Orjan; Gardmark, Anna

    2011-01-01

    -up nor top-down, but rather through multiple external and internal drivers. While in many studies single drivers have been identified, potential synergies of multiple factors, as well as their relative importance in regulating population dynamics of small pelagic fish, is a largely unresolved issue....... Using a statistical, age-structured modeling approach, we demonstrate the relative importance and influence of bottom-up (e.g., climate, zooplankton availability) and top-down (i.e., fishing and predation) factors on the population dynamics of Bothnian Sea herring (Clupea harengus) throughout its life...... cycle. Our results indicate significant bottom-up effects of zooplankton and interspecific competition from sprat (Sprattus sprattus), particularly on younger age classes of herring. Although top-down forcing through fishing and predation by grey seals (Halichoerus grypus) and Atlantic cod (Gadus morhua...

  8. Integrating population dynamics into mapping human exposure to seismic hazard

    Directory of Open Access Journals (Sweden)

    S. Freire

    2012-11-01

    Full Text Available Disaster risk is not fully characterized without taking into account vulnerability and population exposure. Assessment of earthquake risk in urban areas would benefit from considering the variation of population distribution at more detailed spatial and temporal scales, and from a more explicit integration of this improved demographic data with existing seismic hazard maps. In the present work, "intelligent" dasymetric mapping is used to model population dynamics at high spatial resolution in order to benefit the analysis of spatio-temporal exposure to earthquake hazard in a metropolitan area. These night- and daytime-specific population densities are then classified and combined with seismic intensity levels to derive new spatially-explicit four-class-composite maps of human exposure. The presented approach enables a more thorough assessment of population exposure to earthquake hazard. Results show that there are significantly more people potentially at risk in the daytime period, demonstrating the shifting nature of population exposure in the daily cycle and the need to move beyond conventional residence-based demographic data sources to improve risk analyses. The proposed fine-scale maps of human exposure to seismic intensity are mainly aimed at benefiting visualization and communication of earthquake risk, but can be valuable in all phases of the disaster management process where knowledge of population densities is relevant for decision-making.

  9. [Population dynamics of oligosporous actinomycetes in Chernozem soil].

    Science.gov (United States)

    Zenova, G M; Mikhaĭlova, N V; Zviagintsev, D G

    2000-01-01

    Investigation of the dynamics of an oligosporous actinomycete population in chernozem soil in the course of succession induced by soil wetting allowed us to reveal the time intervals and conditions optimal for the isolation of particular oligosporous actinomycetes. Saccharopolysporas and microbisporas proved to be best isolated in the early and late stages of succession, whereas actinomycetes of the subgroup Actinomadura and saccharomonosporas could be best isolated in the early and intermediate stages of succession.

  10. Scaling up population dynamic processes in a ladybird–aphid

    Czech Academy of Sciences Publication Activity Database

    Houdková, Kateřina; Kindlmann, Pavel

    2006-01-01

    Roč. 48, - (2006), s. 323-332 ISSN 1438-3896 R&D Projects: GA ČR(CZ) GEDIV/06/E013; GA MŠk(CZ) LC06073; GA AV ČR(CZ) IAA6087301; GA ČR(CZ) GD206/03/H034 Keywords : Aphids * Egg window * Ladybirds * Metapopulation * Model * Population dynamics Subject RIV: EH - Ecology, Behaviour Impact factor: 1.534, year: 2006

  11. Learning to Estimate Dynamical State with Probabilistic Population Codes.

    Directory of Open Access Journals (Sweden)

    Joseph G Makin

    2015-11-01

    Full Text Available Tracking moving objects, including one's own body, is a fundamental ability of higher organisms, playing a central role in many perceptual and motor tasks. While it is unknown how the brain learns to follow and predict the dynamics of objects, it is known that this process of state estimation can be learned purely from the statistics of noisy observations. When the dynamics are simply linear with additive Gaussian noise, the optimal solution is the well known Kalman filter (KF, the parameters of which can be learned via latent-variable density estimation (the EM algorithm. The brain does not, however, directly manipulate matrices and vectors, but instead appears to represent probability distributions with the firing rates of population of neurons, "probabilistic population codes." We show that a recurrent neural network-a modified form of an exponential family harmonium (EFH-that takes a linear probabilistic population code as input can learn, without supervision, to estimate the state of a linear dynamical system. After observing a series of population responses (spike counts to the position of a moving object, the network learns to represent the velocity of the object and forms nearly optimal predictions about the position at the next time-step. This result builds on our previous work showing that a similar network can learn to perform multisensory integration and coordinate transformations for static stimuli. The receptive fields of the trained network also make qualitative predictions about the developing and learning brain: tuning gradually emerges for higher-order dynamical states not explicitly present in the inputs, appearing as delayed tuning for the lower-order states.

  12. Building the bridge between animal movement and population dynamics.

    Science.gov (United States)

    Morales, Juan M; Moorcroft, Paul R; Matthiopoulos, Jason; Frair, Jacqueline L; Kie, John G; Powell, Roger A; Merrill, Evelyn H; Haydon, Daniel T

    2010-07-27

    While the mechanistic links between animal movement and population dynamics are ecologically obvious, it is much less clear when knowledge of animal movement is a prerequisite for understanding and predicting population dynamics. GPS and other technologies enable detailed tracking of animal location concurrently with acquisition of landscape data and information on individual physiology. These tools can be used to refine our understanding of the mechanistic links between behaviour and individual condition through 'spatially informed' movement models where time allocation to different behaviours affects individual survival and reproduction. For some species, socially informed models that address the movements and average fitness of differently sized groups and how they are affected by fission-fusion processes at relevant temporal scales are required. Furthermore, as most animals revisit some places and avoid others based on their previous experiences, we foresee the incorporation of long-term memory and intention in movement models. The way animals move has important consequences for the degree of mixing that we expect to find both within a population and between individuals of different species. The mixing rate dictates the level of detail required by models to capture the influence of heterogeneity and the dynamics of intra- and interspecific interaction.

  13. Border Collision Bifurcations in a Generalized Model of Population Dynamics

    Directory of Open Access Journals (Sweden)

    Lilia M. Ladino

    2016-01-01

    Full Text Available We analyze the dynamics of a generalized discrete time population model of a two-stage species with recruitment and capture. This generalization, which is inspired by other approaches and real data that one can find in literature, consists in considering no restriction for the value of the two key parameters appearing in the model, that is, the natural death rate and the mortality rate due to fishing activity. In the more general case the feasibility of the system has been preserved by posing opportune formulas for the piecewise map defining the model. The resulting two-dimensional nonlinear map is not smooth, though continuous, as its definition changes as any border is crossed in the phase plane. Hence, techniques from the mathematical theory of piecewise smooth dynamical systems must be applied to show that, due to the existence of borders, abrupt changes in the dynamic behavior of population sizes and multistability emerge. The main novelty of the present contribution with respect to the previous ones is that, while using real data, richer dynamics are produced, such as fluctuations and multistability. Such new evidences are of great interest in biology since new strategies to preserve the survival of the species can be suggested.

  14. Comparison of molecular tests for the diagnosis of malaria in Honduras.

    Science.gov (United States)

    Fontecha, Gustavo A; Mendoza, Meisy; Banegas, Engels; Poorak, Mitra; De Oliveira, Alexandre M; Mancero, Tamara; Udhayakumar, Venkatachalam; Lucchi, Naomi W; Mejia, Rosa E

    2012-04-18

    Honduras is a tropical country with more than 70% of its population living at risk of being infected with either Plasmodium vivax or Plasmodium falciparum. Laboratory diagnosis is a very important factor for adequate treatment and management of malaria. In Honduras, malaria is diagnosed by both, microscopy and rapid diagnostic tests and to date, no molecular methods have been implemented for routine diagnosis. However, since mixed infections, and asymptomatic and low-parasitaemic cases are difficult to detect by light microscopy alone, identifying appropriate molecular tools for diagnostic applications in Honduras deserves further study. The present study investigated the utility of different molecular tests for the diagnosis of malaria in Honduras. A total of 138 blood samples collected as part of a clinical trial to assess the efficacy of chloroquine were used: 69 microscopically confirmed P. falciparum positive samples obtained on the day of enrollment and 69 follow-up samples obtained 28 days after chloroquine treatment and shown to be malaria negative by microscopy. Sensitivity and specificity of microscopy was compared to an 18 s ribosomal RNA gene-based nested PCR, two single-PCR reactions designed to detect Plasmodium falciparum infections, one single-PCR to detect Plasmodium vivax infections, and one multiplex one-step PCR reaction to detect both parasite species. Of the 69 microscopically positive P. falciparum samples, 68 were confirmed to be P. falciparum-positive by two of the molecular tests used. The one sample not detected as P. falciparum by any of the molecular tests was shown to be P. vivax-positive by a reference molecular test indicating a misdiagnosis by microscopy. The reference molecular test detected five cases of P. vivax/P. falciparum mixed infections, which were not recognized by microscopy as mixed infections. Only two of these mixed infections were recognized by a multiplex test while a P. vivax-specific polymerase chain reaction (PCR

  15. La situación económica: social determinants of contraceptive use in rural Honduras.

    Science.gov (United States)

    Hall, Marissa G; Garrett, Jenna J; Barrington, Clare

    2014-01-01

    Contraceptive use is an important determinant of unintended pregnancy, but little is known about the social and structural factors that determine women's contraceptive use in rural Honduras. In this study, we aim to characterise the individual and social determinants of contraceptive use among women in rural Honduras. In 2011 and 2012, we conducted 14 interviews and 2 focus groups with women 18 years and older. In our analysis, we created a family-planning narrative for each participant and coded transcripts around key emergent themes related to these determinants. We found that social determinants--including poverty, gender dynamics and availability of family-planning methods--had a strong influence on contraceptive use among women in our sample. Study participants stated that they were faced with a difficult economic situation compounded by rising prices of basic goods and diminishing job opportunities. Paradoxically, at the same time that the economic situation led women to seek contraception, it also contributed to the structural barriers that limited their ability to obtain their method of choice and maintain continuous contraceptive use. Our findings suggest the need for multi-level efforts to create an enabling and sustainable environment for family planning among women in rural Honduras.

  16. Homogenization techniques for population dynamics in strongly heterogeneous landscapes.

    Science.gov (United States)

    Yurk, Brian P; Cobbold, Christina A

    2018-12-01

    An important problem in spatial ecology is to understand how population-scale patterns emerge from individual-level birth, death, and movement processes. These processes, which depend on local landscape characteristics, vary spatially and may exhibit sharp transitions through behavioural responses to habitat edges, leading to discontinuous population densities. Such systems can be modelled using reaction-diffusion equations with interface conditions that capture local behaviour at patch boundaries. In this work we develop a novel homogenization technique to approximate the large-scale dynamics of the system. We illustrate our approach, which also generalizes to multiple species, with an example of logistic growth within a periodic environment. We find that population persistence and the large-scale population carrying capacity is influenced by patch residence times that depend on patch preference, as well as movement rates in adjacent patches. The forms of the homogenized coefficients yield key theoretical insights into how large-scale dynamics arise from the small-scale features.

  17. Drivers of waterfowl population dynamics: from teal to swans

    Science.gov (United States)

    Koons, David N.; Gunnarsson, Gunnar; Schmutz, Joel A.; Rotella, Jay J.

    2014-01-01

    Waterfowl are among the best studied and most extensively monitored species in the world. Given their global importance for sport and subsistence hunting, viewing and ecosystem functioning, great effort has been devoted since the middle part of the 20th century to understanding both the environmental and demographic mechanisms that influence waterfowl population and community dynamics. Here we use comparative approaches to summarise and contrast our understanding ofwaterfowl population dynamics across species as short-lived as the teal Anas discors and A.crecca to those such as the swans Cygnus sp. which have long life-spans. Specifically, we focus on population responses to vital rate perturbations across life history strategies, discuss bottom-up and top-down responses of waterfowlpopulations to global change, and summarise our current understanding of density dependence across waterfowl species. We close by identifying research needs and highlight ways to overcome the challenges of sustainably managing waterfowl populations in the 21st century.

  18. On the population dynamics of the malaria vector

    International Nuclear Information System (INIS)

    Ngwa, G.A.

    2005-10-01

    A deterministic differential equation model for the population dynamics of the human malaria vector is derived and studied. Conditions for the existence and stability of a non-zero steady state vector population density are derived. These reveal that a threshold parameter, the vectorial basic reproduction number, exist and the vector can establish itself in the community if and only if this parameter exceeds unity. When a non-zero steady state population density exists, it can be stable but it can also be driven to instability via a Hopf Bifurcation to periodic solutions, as a parameter is varied in parameter space. By considering a special case, an asymptotic perturbation analysis is used to derive the amplitude of the oscillating solutions for the full non-linear system. The present modelling exercise and results show that it is possible to study the population dynamics of disease vectors, and hence oscillatory behaviour as it is often observed in most indirectly transmitted infectious diseases of humans, without recourse to external seasonal forcing. (author)

  19. Linking animal population dynamics to alterations in foraging behaviour

    DEFF Research Database (Denmark)

    Nabe-Nielsen, Jacob; Sibly, Richard; Tougaard, Jakob

    Background/Question/Methods The survival of animal populations is strongly influenced by the individuals’ ability to forage efficiently, yet there are few studies of how populations respond when disturbances cause animals to deviate from their natural foraging behavior. Animals that respond...... that are increasingly exposed to noise from ships, wind turbines, etc. In the present study we investigate how the dynamics of the harbor porpoise population (Phocoena phocoena) in the inner Danish waters is influenced by disturbances using an agent- based simulation model. In the model animal movement, and hence...... the animals’ ability to forage efficiently and to sustain their energy intake, is influenced by noise emitted from wind turbines and ships. The energy levels in turn affect their survival. The fine-scale movements of the simulated animals was governed by a spatial memory, which allowed the model to produce...

  20. Studies on population dynamic of diamondback moth in the field

    International Nuclear Information System (INIS)

    Malakrong, A.; Limohpasmanee, W.; Keawchoung, P.; Kodcharint, P.

    1994-01-01

    The population dynamic of diamondback moth larva in the field was studied at Khao Khor High-land Agricultural Research Station during August-October 1993 and February-April 1994. The distribution patterns of diamondback moth larva was clumped when population was low and would change to be random when population was high. The maximun and minimum number of diamondback moth in the field were 71,203 and 2,732 larva/rai during March and September. Temperature, rainfall and age of cabbage were slightly relative with number of larva (r=-0.2891, p=0.30; r=-0.2816, p=0.31 and r=0.2931, p=0.29 respectively) but relative humidity has no effect on number of larva

  1. Climate change impacts on maize and dry bean yields of smallholder farmers in Honduras

    Directory of Open Access Journals (Sweden)

    MENDOZA, Carlos O.

    2013-06-01

    Full Text Available The rotation maize and dry bean provides the main food supply of smallholder farmers in Honduras. Crop model assessment of climate change impacts (2070–2099 compared to a 1961–1990 baseline on a maize–dry bean rotation for several sites across a range of climatic zones and elevations in Honduras. Low productivity systems, together with an uncertain future climate, pose a high level of risk for food security. The cropping systems simulation dynamic model CropSyst was calibrated and validated upon field trail site at Zamorano, then run with baseline and future climate scenarios based upon general circulation models (GCM and the ClimGen synthetic daily weather generator. Results indicate large uncertainty in crop production from various GCM simulations and future emissions scenarios, but generally reduced yields at low elevations by 0 % to 22 % in suitable areas for crop production and increased yield at the cooler, on the hillsides, where farming needs to reduce soil erosion with conservation techniques. Further studies are needed to investigate strategies to reduce impacts and to explore adaptation tactics.

  2. Honduras : tous les projets | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Sujet: TAXATION, CONSUMER DEMAND, Fiscal policy, ECONOMETRIC ANALYSIS, SMOKING, TOBACCO INDUSTRY. Région: North and Central America, South America, Guatemala, Honduras. Programme: Alimentation, environnement et santé. Financement total : CA$ 128,000.00. Prévention de la violence chez les ...

  3. Political ecology, mountain agriculture, and knowledge in Honduras

    NARCIS (Netherlands)

    Jansen, K.

    1998-01-01

    The social and biophysical processes entailed in environmental deterioration are the subject of intense debate in Honduras, one of the poorest countries of Latin America. This book analyses the political ecology of precarious farming in mountainous areas. The author evaluates a rich array

  4. Teachers and Taxis: Corruption in the Education Sector in Honduras

    OpenAIRE

    Fontana, Alessandra

    2008-01-01

    Honduras invests large sums in education,but powerful teachers' unions and political appointments hinder reforms in a sector vulnerable to corruption and lacking in civil society monitoring. For current decentralisation plans to impact positively on education services, local auditing skills need to be improved, parents must be given a bigger role, and unions must adhere to codes of conduct.

  5. Honduras : tous les projets | Page 2 | CRDI - Centre de recherches ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... South America, Chile, Colombia, Honduras, North and Central America, Mexico ... Élaboration d'une stratégie de lutte intégrée contre la pollution de l'eau à ... SANITATION SERVICES, WATER QUALITY, WATER POLLUTION, WATER ...

  6. First report of "Candidatus Liberibacter solanacearum" infecting eggplant in Honduras

    Science.gov (United States)

    In May of 2012, eggplant (Solanum melongena) plants in an experimental research plot located at Zamorano in the Department of Francisco Morazán, Honduras, were observed with symptoms that included leaf chlorosis and cupping, overall stunting, and production of small and malformed fruits. The researc...

  7. A provisional annotated list of the Lepidoptera of Honduras

    Science.gov (United States)

    A biodiversity inventory of the Lepidoptera of Pico Bonito National Park and vicinity, in the Department of Atlantida of northern Honduras, has been initiated and will be conducted to obtain baseline data. We present a revised checklist of Honduran butterfly species (updated from the initial 1967 l...

  8. Social Integration and Health Behavioral Change in San Luis, Honduras

    Science.gov (United States)

    McQuestion, Michael J.; Calle, Ana Quijano; Drasbek, Christopher; Harkins, Thomas; Sagastume, Lourdes J.

    2010-01-01

    This study explores the effects of social integration on behavioral change in the course of an intensive, community-based public health intervention. The intervention trained volunteers and mobilized local organizations to promote 16 key family health practices in rural San Luis, Honduras, during 2004 to 2006. A mixed methods approach is used.…

  9. Child Marriage, Agency, and Schooling in Rural Honduras

    Science.gov (United States)

    Murphy-Graham, Erin; Leal, Graciela

    2015-01-01

    This article examines the relationships between child marriage, agency, and schooling in rural Honduras. Through an in-depth qualitative case study, we address the following questions: (1) In what ways, if any, do girls exercise agency in their decision to marry? (2) How might education enhance girls' agency, expanding their choice sets and…

  10. First report of "Candidatus Liberibacter solanacearum" on pepper in Honduras

    Science.gov (United States)

    In 2012, bell pepper (Capsicum annuum) plants exhibiting symptoms that resembled those of the bacterium “Candidatus Liberibacter solanacearum” infection were observed in commercial pepper fields in several departments in Honduras, including Francisco Morazán, Ocotepeque, El Paraíso, and Olancho. Man...

  11. A new species of Poecilia from Honduras (Teleostei: Poeciliidae)

    NARCIS (Netherlands)

    Poeser, F.N.

    2011-01-01

    A new species of Poecilia from the Atlantic slopes of Honduras is described and assigned to the subgenus Mollienesia. Poecilia hondurensis, new species, differs from all congeners in the combination of having tricuspid teeth on the inner of both jaws and lacking a prominent spine or hook on the

  12. First report of 'Candidatus Liberibacter solanacearum' on tomato in Honduras

    Science.gov (United States)

    In April of 2012, tomato plants grown in several departments of Honduras, were observed with symptoms resembling those of “Candidatus Liberibacter solanacearum” (Lso) infection. The symptoms include overall chlorosis, severe stunting, leaf cupping, excessive branching of axillary shoots, and leaf pu...

  13. Anthracnose disease evaluation of sorghum germplasm from Honduras

    Science.gov (United States)

    Germplasm collections are important resources for sorghum improvement and 17 accessions from Honduras were inoculated with Colletotrichum sublineolum and evaluated at the Tropical Agriculture Research Station in Isabela, Puerto Rico during the 2005 and 2006 growing seasons to identify sources of ant...

  14. Population Dynamics of Early Human Migration in Britain.

    Directory of Open Access Journals (Sweden)

    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.

  15. Environmental influence on population dynamics of the bivalve Anomalocardia brasiliana

    Science.gov (United States)

    Corte, Guilherme Nascimento; Coleman, Ross A.; Amaral, A. Cecília Z.

    2017-03-01

    Understanding how species respond to the environment in terms of population attributes (e.g. abundance, growth, mortality, fecundity, and productivity) is essential to protect ecologically and economically important species. Nevertheless, responses of macrobenthic populations to environmental features are overlooked due to the need of consecutive samplings and time-consuming measurements. We examined the population dynamics of the filter-feeding bivalve Anomalocardia brasiliana on a tidal flat over the course of one year to investigate the hypothesis that, as accepted for macrobenthic communities, populations inhabiting environments with low hydrodynamic conditions such as tidal flat should have higher attributes than populations inhabiting more energetic habitats (i.e. areas more influenced by wave energy such as reflective and intermediate beaches). This would be expected because the harsh conditions of more energetic habitats force organisms to divert more energy towards maintenance, resulting in lower population attributes. We found that A. brasiliana showed moderate growth and secondary production at the study area. Moreover the recruitment period was restricted to a few months. A comparison with previous studies showed that, contrary to expected, A. brasiliana populations from areas with low hydrodynamic conditions have lower abundance, growth, recruitment and turnover rate. It is likely that morphodynamic characteristics recorded in these environments, such as larger periods of air exposure and lower water circulation, may affect food conditions for filter-feeding species and increase competition. In addition, these characteristics may negatively affect macrobenthic species by enhancing eutrophication processes and anoxia. Overall, our results suggest that models accepted and applied at the macrobenthic community level might not be directly extended to A. brasiliana populations.

  16. Alternating event processes during lifetimes: population dynamics and statistical inference.

    Science.gov (United States)

    Shinohara, Russell T; Sun, Yifei; Wang, Mei-Cheng

    2018-01-01

    In the literature studying recurrent event data, a large amount of work has been focused on univariate recurrent event processes where the occurrence of each event is treated as a single point in time. There are many applications, however, in which univariate recurrent events are insufficient to characterize the feature of the process because patients experience nontrivial durations associated with each event. This results in an alternating event process where the disease status of a patient alternates between exacerbations and remissions. In this paper, we consider the dynamics of a chronic disease and its associated exacerbation-remission process over two time scales: calendar time and time-since-onset. In particular, over calendar time, we explore population dynamics and the relationship between incidence, prevalence and duration for such alternating event processes. We provide nonparametric estimation techniques for characteristic quantities of the process. In some settings, exacerbation processes are observed from an onset time until death; to account for the relationship between the survival and alternating event processes, nonparametric approaches are developed for estimating exacerbation process over lifetime. By understanding the population dynamics and within-process structure, the paper provide a new and general way to study alternating event processes.

  17. Stochastic population dynamics in spatially extended predator-prey systems

    Science.gov (United States)

    Dobramysl, Ulrich; Mobilia, Mauro; Pleimling, Michel; Täuber, Uwe C.

    2018-02-01

    Spatially extended population dynamics models that incorporate demographic noise serve as case studies for the crucial role of fluctuations and correlations in biological systems. Numerical and analytic tools from non-equilibrium statistical physics capture the stochastic kinetics of these complex interacting many-particle systems beyond rate equation approximations. Including spatial structure and stochastic noise in models for predator-prey competition invalidates the neutral Lotka-Volterra population cycles. Stochastic models yield long-lived erratic oscillations stemming from a resonant amplification mechanism. Spatially extended predator-prey systems display noise-stabilized activity fronts that generate persistent correlations. Fluctuation-induced renormalizations of the oscillation parameters can be analyzed perturbatively via a Doi-Peliti field theory mapping of the master equation; related tools allow detailed characterization of extinction pathways. The critical steady-state and non-equilibrium relaxation dynamics at the predator extinction threshold are governed by the directed percolation universality class. Spatial predation rate variability results in more localized clusters, enhancing both competing species’ population densities. Affixing variable interaction rates to individual particles and allowing for trait inheritance subject to mutations induces fast evolutionary dynamics for the rate distributions. Stochastic spatial variants of three-species competition with ‘rock-paper-scissors’ interactions metaphorically describe cyclic dominance. These models illustrate intimate connections between population dynamics and evolutionary game theory, underscore the role of fluctuations to drive populations toward extinction, and demonstrate how space can support species diversity. Two-dimensional cyclic three-species May-Leonard models are characterized by the emergence of spiraling patterns whose properties are elucidated by a mapping onto a complex

  18. Population Dynamics of the Mediterranean Fruit Fly in Montenegro

    Directory of Open Access Journals (Sweden)

    Sanja Radonjić

    2013-01-01

    Full Text Available Population dynamics of the Mediterranean fruit fly was studied along Montenegro seacoast. Tephri traps baited with 3 component female-biased attractants were used in 11 different localities to monitor the fruit fly population in commercial citrus orchards, mixed-fruit orchards, and in backyards. From 2008–2010, the earliest captures were recorded no earlier than July. In 2011, the first adult fly was detected in mid-June. Low captures rates were recorded in July and August (below 0.5 flies per trap per day; FTD and peaked from mid-September to the end of October of each year. Our results indicate fluctuation of fly per trap per day depending on dates of inspection and locality, with significant differences in the adult population density. A maximum population was always reached in the area of Budva-Herceg Novi with an FTD of 66.5, 89.5, 71.63, and 24.64 (from 2008–2011 respectively. Fly activity lasts from mid-June/early-July to end December, with distinct seasonal variation in the population.

  19. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Honduras

    International Nuclear Information System (INIS)

    1977-08-01

    In 1953, the U.S. Atomic Energy Commission, on invitation of the government of Honduras, conducted uranium reconnaissance in parts of the country. The survey consisted of scintillometric examination of all formations, veins, dikes, sills and contacts along more than 1,500 km of road. Additionally, 17 mines and prospects were examined, but in no location were uranium occurrences found. The largest and most consistently radioactive deposit noted was a body of volcanic ash at Santa Rosa de Copan, a sample of which assayed 15 ppm U 3 O 8 . A uranium prospect has been described from the Yatnala area in northwest Honduras. Uraninite and oxidation products occur in association with copper and mercury minerals in veinlets as well as disseminations in a Lower Cretaceous limestone conglomerate, the llama Formation. The llama Formation is the conglomeratic facies of the Atima (limestone) Formation, both of which are in the Yojoa Group. At the time of the U. N. development program survey in May, 1970, no uranium deposits were known in Honduras. Information is not available on current exploration in Honduras. The state owns most mineral deposits but may grant rights for exploration and exploitation of the subsoil. Mineral and surface titles are separate. Deposits of uranium and its salts, thorium and similar atomic energy substances are reserved to the state. Foreign citizens and companies, with some exceptions, may acquire mineral rights. Several groups of sediments might be of interest for uranium exploration. The Todos Santos redbeds and the El Plan Formation are both shallow marine and hence may contain marginal marine facies favorable for uranium. In the southern and central Cordillera, the Valle de Angeles sediments, particularly the sandstones, may be of interest. The contacts between Permian granites and schists (Paleozoic) may also warrant attention. Lacking further information on which to base a more optimistic outlook, it is estimated that the uranium potential of

  20. Population dynamics of Ascaris suum in trickle-infected pigs.

    Science.gov (United States)

    Nejsum, Peter; Thamsborg, Stig M; Petersen, Heidi H; Kringel, Helene; Fredholm, Merete; Roepstorff, Allan

    2009-10-01

    The population dynamics of Ascaris suum was studied by long-term exposure of pigs to infective eggs. The pigs were experimentally inoculated with 25 A. suum eggs/kg/day, and 7, 8, and 8 pigs were necropsied at weeks 4, 8, and 14 postinoculation (PI), respectively. Despite the fact that the pigs were continuously reinfected, dramatic reductions in numbers of liver lesions (white spots) and migrating lung larvae were observed as a function of time. However, even at the end of the study, a few larvae were able to complete migration, but these larvae seemed unable to mature in the small intestine. Thus, the adult worm population seemed to consist of worms from the first part of the exposure period. The noticeable decrease in number of white spots suggests that the level of exposure is not reflected in the number of white spots in the late phase of a continuous infection. The serum levels of A. suum L3-specific IgG1 and IgA were significantly elevated by week 4 PI, after which the antibody levels declined. The population dynamics and parasite regulating mechanisms are discussed for A. suum in pigs as well as for the closely related species A. lumbricoides in humans.

  1. Periodic matrix models for seasonal dynamics of structured populations with application to a seabird population.

    Science.gov (United States)

    Cushing, J M; Henson, Shandelle M

    2018-02-03

    For structured populations with an annual breeding season, life-stage interactions and behavioral tactics may occur on a faster time scale than that of population dynamics. Motivated by recent field studies of the effect of rising sea surface temperature (SST) on within-breeding-season behaviors in colonial seabirds, we formulate and analyze a general class of discrete-time matrix models designed to account for changes in behavioral tactics within the breeding season and their dynamic consequences at the population level across breeding seasons. As a specific example, we focus on egg cannibalism and the daily reproductive synchrony observed in seabirds. Using the model, we investigate circumstances under which these life history tactics can be beneficial or non-beneficial at the population level in light of the expected continued rise in SST. Using bifurcation theoretic techniques, we study the nature of non-extinction, seasonal cycles as a function of environmental resource availability as they are created upon destabilization of the extinction state. Of particular interest are backward bifurcations in that they typically create strong Allee effects in population models which, in turn, lead to the benefit of possible (initial condition dependent) survival in adverse environments. We find that positive density effects (component Allee effects) due to increased adult survival from cannibalism and the propensity of females to synchronize daily egg laying can produce a strong Allee effect due to a backward bifurcation.

  2. Effects of Peanut-Tobacco Rotations on Population Dynamics of Meloidogyne arenaria in Mixed Race Populations

    OpenAIRE

    Hirunsalee, Anan; Barker, K. R.; Beute, M. K.

    1995-01-01

    A 3-year microplot study was initiated to characterize the population dynamics, reproduction potential, and survivorship of single or mixed populations of Meloidogyne arenaria race 1 (Ma1) and race 2 (Ma2), as affected by crop rotations of peanut 'Florigiant' and M. incognita races 1 and 3-resistant 'McNair 373' and susceptible 'Coker 371-Gold' tobacco. Infection, reproduction, and root damage by Ma2 on peanut and by Ma1 on resistant tobacco were limited in the first year. Infection, reproduc...

  3. Primary care provision by volunteer medical brigades in Honduras: a health record review of more than 2,500 patients over three years.

    Science.gov (United States)

    Martiniuk, Alexandra L C; Adunuri, Nikesh; Negin, Joel; Tracey, Patti; Fontecha, Claudio; Caldwell, Paul

    2012-01-01

    The weak health system in Honduras contributes to poor health indicators. To improve population health, a number of volunteer medical brigades from developed countries provide health services in Honduras. To date, there is little information on the brigades' activities and impact. The primary objective of this article is to increase understanding of the type of health care provided by voluntary medical brigades by evaluating and presenting data on patients' presenting symptoms, diagnoses, and care outcomes. The article focuses on an ongoing medical brigade organized by Canadian health professionals in conjunction with Honduras' largest national non-governmental organization. This is a descriptive study of data that are routinely collected by volunteer Canadian health care professionals. Data on all patients presenting to temporary primary health care facilities across Honduras between 2006 and 2009 were analyzed. The data were used to analyze patient demographics, presenting symptoms, diagnoses, and treatments. We found that the brigades provide additional human resources to the relatively weak Honduran health care system. However, while brigades may increase solidarity between Hondurans and Canadians, concerns persist regarding cost-effectiveness and continuity of care for conditions treated by short-term brigade volunteers. Greater scrutiny is needed to increase brigades' effectiveness and ensure they are supportive of domestic health systems.

  4. Exploiting Fast-Variables to Understand Population Dynamics and Evolution

    Science.gov (United States)

    Constable, George W. A.; McKane, Alan J.

    2017-11-01

    We describe a continuous-time modelling framework for biological population dynamics that accounts for demographic noise. In the spirit of the methodology used by statistical physicists, transitions between the states of the system are caused by individual events while the dynamics are described in terms of the time-evolution of a probability density function. In general, the application of the diffusion approximation still leaves a description that is quite complex. However, in many biological applications one or more of the processes happen slowly relative to the system's other processes, and the dynamics can be approximated as occurring within a slow low-dimensional subspace. We review these time-scale separation arguments and analyse the more simple stochastic dynamics that result in a number of cases. We stress that it is important to retain the demographic noise derived in this way, and emphasise this point by showing that it can alter the direction of selection compared to the prediction made from an analysis of the corresponding deterministic model.

  5. Cooperation guided by the coexistence of imitation dynamics and aspiration dynamics in structured populations

    Science.gov (United States)

    Xu, Kuangyi; Li, Kun; Cong, Rui; Wang, Long

    2017-02-01

    In the framework of the evolutionary game theory, two fundamentally different mechanisms, the imitation process and the aspiration-driven dynamics, can be adopted by players to update their strategies. In the former case, individuals imitate the strategy of a more successful peer, while in the latter case individuals change their strategies based on a comparison of payoffs they collect in the game to their own aspiration levels. Here we explore how cooperation evolves for the coexistence of these two dynamics. Intriguingly, cooperation reaches its lowest level when a certain moderate fraction of individuals pick aspiration-level-driven rule while the others choose pairwise comparison rule. Furthermore, when individuals can adjust their update rules besides their strategies, either imitation dynamics or aspiration-driven dynamics will finally take over the entire population, and the stationary cooperation level is determined by the outcome of competition between these two dynamics. We find that appropriate synergetic effects and moderate aspiration level boost the fixation probability of aspiration-driven dynamics most effectively. Our work may be helpful in understanding the cooperative behavior induced by the coexistence of imitation dynamics and aspiration dynamics in the society.

  6. Population Dynamics of Patients with Bacterial Resistance in Hospital Environment

    Directory of Open Access Journals (Sweden)

    Leilei Qu

    2016-01-01

    Full Text Available During the past decades, the increase of antibiotic resistance has become a major concern worldwide. The researchers found that superbugs with new type of resistance genes (NDM-1 have two aspects of transmission characteristics; the first is that the antibiotic resistance genes can horizontally transfer among bacteria, and the other is that the superbugs can spread between humans through direct contact. Based on these two transmission mechanisms, we study the dynamics of population in hospital environment where superbugs exist. In this paper, we build three mathematic models to illustrate the dynamics of patients with bacterial resistance in hospital environment. The models are analyzed using stability theory of differential equations. Positive equilibrium points of the system are investigated and their stability analysis is carried out. Moreover, the numerical simulation of the proposed model is also performed which supports the theoretical findings.

  7. Dynamic population gratings in rare-earth-doped optical fibres

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, Serguei [Optics Department, CICESE, km.107 carr. Tijuana-Ensenada, Ensenada, 22860, BC (Mexico)], E-mail: steps@cicese.mx

    2008-11-21

    Dynamic Bragg gratings can be recorded in rare-earth (e.g. Er, Yb) doped optical fibres by two counter-propagating mutually coherent laser waves via local saturation of the fibre optical absorption or gain (in optically pumped fibres). Typical recording cw light power needed for efficient grating formation is of sub-mW-mW scale which results in characteristic recording/erasure times of 10-0.1 ms. This review paper discusses fundamental aspects of the population grating formation, their basic properties, relating wave-mixing processes and also considers different applications of these dynamic gratings in single-frequency fibre lasers, tunable filters, optical fibre sensors and adaptive interferometry.

  8. Dynamic population gratings in rare-earth-doped optical fibres

    International Nuclear Information System (INIS)

    Stepanov, Serguei

    2008-01-01

    Dynamic Bragg gratings can be recorded in rare-earth (e.g. Er, Yb) doped optical fibres by two counter-propagating mutually coherent laser waves via local saturation of the fibre optical absorption or gain (in optically pumped fibres). Typical recording cw light power needed for efficient grating formation is of sub-mW-mW scale which results in characteristic recording/erasure times of 10-0.1 ms. This review paper discusses fundamental aspects of the population grating formation, their basic properties, relating wave-mixing processes and also considers different applications of these dynamic gratings in single-frequency fibre lasers, tunable filters, optical fibre sensors and adaptive interferometry.

  9. Population dynamics of minimally cognitive individuals. Part 2: Dynamics of time-dependent knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Schmieder, R.W.

    1995-07-01

    The dynamical principle for a population of interacting individuals with mutual pairwise knowledge, presented by the author in a previous paper for the case of constant knowledge, is extended to include the possibility that the knowledge is time-dependent. Several mechanisms are presented by which the mutual knowledge, represented by a matrix K, can be altered, leading to dynamical equations for K(t). The author presents various examples of the transient and long time asymptotic behavior of K(t) for populations of relatively isolated individuals interacting infrequently in local binary collisions. Among the effects observed in the numerical experiments are knowledge diffusion, learning transients, and fluctuating equilibria. This approach will be most appropriate to small populations of complex individuals such as simple animals, robots, computer networks, agent-mediated traffic, simple ecosystems, and games. Evidence of metastable states and intermittent switching leads them to envision a spectroscopy associated with such transitions that is independent of the specific physical individuals and the population. Such spectra may serve as good lumped descriptors of the collective emergent behavior of large classes of populations in which mutual knowledge is an important part of the dynamics.

  10. Do farming practices influence population dynamics of rodents?

    DEFF Research Database (Denmark)

    Massawe, A W; Rwamugira, W; Leirs, Herwig

    2007-01-01

    A capture-mark-recapture study was conducted in crop fields in Morogoro, Tanzania, to investigate how the population dynamics of multimammate field rats, Mastomys natalensis, was influenced by the commonly practised land preparation methods and cropping systems. Two land preparation methods (trac...... practices. In maize fields in Tanzania, the crop is most susceptible to damage by M. natalensis in the first 2 weeks after planting, and therefore, lower densities of rodents will result into lower crop damage in tractor ploughed fields....

  11. Neural Population Dynamics during Reaching Are Better Explained by a Dynamical System than Representational Tuning.

    Science.gov (United States)

    Michaels, Jonathan A; Dann, Benjamin; Scherberger, Hansjörg

    2016-11-01

    Recent models of movement generation in motor cortex have sought to explain neural activity not as a function of movement parameters, known as representational models, but as a dynamical system acting at the level of the population. Despite evidence supporting this framework, the evaluation of representational models and their integration with dynamical systems is incomplete in the literature. Using a representational velocity-tuning based simulation of center-out reaching, we show that incorporating variable latency offsets between neural activity and kinematics is sufficient to generate rotational dynamics at the level of neural populations, a phenomenon observed in motor cortex. However, we developed a covariance-matched permutation test (CMPT) that reassigns neural data between task conditions independently for each neuron while maintaining overall neuron-to-neuron relationships, revealing that rotations based on the representational model did not uniquely depend on the underlying condition structure. In contrast, rotations based on either a dynamical model or motor cortex data depend on this relationship, providing evidence that the dynamical model more readily explains motor cortex activity. Importantly, implementing a recurrent neural network we demonstrate that both representational tuning properties and rotational dynamics emerge, providing evidence that a dynamical system can reproduce previous findings of representational tuning. Finally, using motor cortex data in combination with the CMPT, we show that results based on small numbers of neurons or conditions should be interpreted cautiously, potentially informing future experimental design. Together, our findings reinforce the view that representational models lack the explanatory power to describe complex aspects of single neuron and population level activity.

  12. Optimal growth entails risky localization in population dynamics

    Science.gov (United States)

    Gueudré, Thomas; Martin, David G.

    2018-03-01

    Essential to each other, growth and exploration are jointly observed in alive and inanimate entities, such as animals, cells or goods. But how the environment's structural and temporal properties weights in this balance remains elusive. We analyze a model of stochastic growth with time correlations and diffusive dynamics that sheds light on the way populations grow and spread over general networks. This model suggests natural explanations of empirical facts in econo-physics or ecology, such as the risk-return trade-off and the Zipf law. We conclude that optimal growth leads to a localized population distribution, but such risky position can be mitigated through the space geometry. These results have broad applicability and are subsequently illustrated over an empirical study of financial data.

  13. Fast stochastic algorithm for simulating evolutionary population dynamics

    Science.gov (United States)

    Tsimring, Lev; Hasty, Jeff; Mather, William

    2012-02-01

    Evolution and co-evolution of ecological communities are stochastic processes often characterized by vastly different rates of reproduction and mutation and a coexistence of very large and very small sub-populations of co-evolving species. This creates serious difficulties for accurate statistical modeling of evolutionary dynamics. In this talk, we introduce a new exact algorithm for fast fully stochastic simulations of birth/death/mutation processes. It produces a significant speedup compared to the direct stochastic simulation algorithm in a typical case when the total population size is large and the mutation rates are much smaller than birth/death rates. We illustrate the performance of the algorithm on several representative examples: evolution on a smooth fitness landscape, NK model, and stochastic predator-prey system.

  14. Outward migration may alter population dynamics and income inequality

    Science.gov (United States)

    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.

  15. State-dependent neutral delay equations from population dynamics.

    Science.gov (United States)

    Barbarossa, M V; Hadeler, K P; Kuttler, C

    2014-10-01

    A novel class of state-dependent delay equations is derived from the balance laws of age-structured population dynamics, assuming that birth rates and death rates, as functions of age, are piece-wise constant and that the length of the juvenile phase depends on the total adult population size. The resulting class of equations includes also neutral delay equations. All these equations are very different from the standard delay equations with state-dependent delay since the balance laws require non-linear correction factors. These equations can be written as systems for two variables consisting of an ordinary differential equation (ODE) and a generalized shift, a form suitable for numerical calculations. It is shown that the neutral equation (and the corresponding ODE--shift system) is a limiting case of a system of two standard delay equations.

  16. [Genetic isolates and inbreeding customs in three rural municipalities from Honduras].

    Science.gov (United States)

    Herrera-Paz, Edwin Francisco

    2016-01-01

    The isonymic method has been amply used to assess the approximate genetic structure of human communities. The objective of the study was to evaluate the magnitude of genetic isolation and inbreeding customs in 57 communities from three rural municipalities of Honduras using isonymy techniques. The list of 408 different surnames from 20712 voters registered in the national electoral organism, residing in the 57 Honduran communities, was used for this study. For each community, random (IR), non-random (IN), and total (IT) isonymy values were calculated in order to assess inbreeding coefficients FST, FIS and FIT. High consanguinity due to isolation and to endogamous customs was unveiled in many communities. Significant deviation from the exogamous behavior typical of many human populations was observed in the three studied municipalities, when compared to other Honduran populations. The studied communities present high consanguinity due to isolation, ethnic segregation and/or endogamous customs.

  17. Effects of Peanut-Tobacco Rotations on Population Dynamics of Meloidogyne arenaria in Mixed Race Populations.

    Science.gov (United States)

    Hirunsalee, A; Barker, K R; Beute, M K

    1995-06-01

    A 3-year microplot study was initiated to characterize the population dynamics, reproduction potential, and survivorship of single or mixed populations of Meloidogyne arenaria race 1 (Ma1) and race 2 (Ma2), as affected by crop rotations of peanut 'Florigiant' and M. incognita races 1 and 3-resistant 'McNair 373' and susceptible 'Coker 371-Gold' tobacco. Infection, reproduction, and root damage by Ma2 on peanut and by Ma1 on resistant tobacco were limited in the first year. Infection, reproduction, and root-damage potentials on susceptible tobacco were similar for Ma1 and Ma2. In the mixed (1:1) population, Ma1 was dominant on peanut and Ma2 was dominant on both tobacco cultivars. Crop rotation affected the population dynamics of different nematode races. For years 2 and 3, the low numbers of Ma1 and Ma2 from a previous-year poor host increased rapidly on suitable hosts. Ma1 had greater reproduction factors ([RF] = population density at harvest/population density at preplandng) than did Ma2 and Ma1 + Ma2 in second-year peanut plots following first-year resistant tobacco, and in third-year peanut plots following second-year tobacco. In mixed infestations, Ma1 predominated over Ma2 in previous-year peanut plots, whereas Ma2 predominated over Ma1 in previous-year tobacco plots. Moderate damage on resistant tobacco was induced by Ma1 in the second year. In the third year, moderate damage on peanut was associated with 'Ma2' from previous-year peanut plots. The resistant tobacco supported sufficient reproduction of Ma1 over 2 years to effect moderate damage and yield suppression to peanut in year 3.

  18. Application of System Dynamics Methodology in Population Analysis

    Directory of Open Access Journals (Sweden)

    August Turina

    2009-09-01

    Full Text Available The goal of this work is to present the application of system dynamics and system thinking, as well as the advantages and possible defects of this analytic approach, in order to improve the analysis of complex systems such as population and, thereby, to monitor more effectively the underlying causes of migrations. This methodology has long been present in interdisciplinary scientific circles, but its scientific contribution has not been sufficiently applied in analysis practice in Croatia. Namely, the major part of system analysis is focused on detailed complexity rather than on dynamic complexity. Generally, the science of complexity deals with emergence, innovation, learning and adaptation. Complexity is viewed according to the number of system components, or through a number of combinations that must be continually analyzed in order to understand and consequently provide adequate decisions. Simulations containing thousands of variables and complex arrays of details distract overall attention from the basic cause patterns and key inter-relations emerging and prevailing within an analyzed population. Systems thinking offers a holistic and integral perspective for observation of the world.

  19. Representation of dynamical stimuli in populations of threshold neurons.

    Directory of Open Access Journals (Sweden)

    Tatjana Tchumatchenko

    2011-10-01

    Full Text Available Many sensory or cognitive events are associated with dynamic current modulations in cortical neurons. This raises an urgent demand for tractable model approaches addressing the merits and limits of potential encoding strategies. Yet, current theoretical approaches addressing the response to mean- and variance-encoded stimuli rarely provide complete response functions for both modes of encoding in the presence of correlated noise. Here, we investigate the neuronal population response to dynamical modifications of the mean or variance of the synaptic bombardment using an alternative threshold model framework. In the variance and mean channel, we provide explicit expressions for the linear and non-linear frequency response functions in the presence of correlated noise and use them to derive population rate response to step-like stimuli. For mean-encoded signals, we find that the complete response function depends only on the temporal width of the input correlation function, but not on other functional specifics. Furthermore, we show that both mean- and variance-encoded signals can relay high-frequency inputs, and in both schemes step-like changes can be detected instantaneously. Finally, we obtain the pairwise spike correlation function and the spike triggered average from the linear mean-evoked response function. These results provide a maximally tractable limiting case that complements and extends previous results obtained in the integrate and fire framework.

  20. Population dynamics of Trichuris suis in trickle-infected pigs.

    Science.gov (United States)

    Nejsum, P; Thamsborg, S M; Petersen, H H; Kringel, H; Fredholm, M; Roepstorff, A

    2009-05-01

    The population dynamics of Trichuris suis in pigs was studied during long-term experimental infections. Twenty-three 10-week-old pigs were inoculated with 5 T. suis eggs/kg/day. Seven, 8, and 8 pigs were necropsied at weeks 4, 8, and 14 post-start of infection (p.i.), respectively. The median numbers of worms in the colon were 538 (min-max: 277-618), 332 (14-1140) and 0 (0-4) at 4, 8, and 14 weeks p.i. respectively, suggesting an increased aggregation of the worms with time and acquisition of nearly sterile immunity. The serum levels of T. suis specific antibodies (IgG1, IgG2 and IgA) peaked at week 8 p.i. By week 14 p.i. the IgG2 and IgA antibody levels remained significantly elevated above the level of week 0. The population dynamics of T. suis trickle infections in pigs is discussed with focus on interpretation of diagnostic and epidemiological data of pigs, the use of pigs as a model for human Trichuris trichiura infections and the novel approach of using T. suis eggs in the treatment of patients with inflammatory bowel disease.

  1. Associations between maternal experiences of intimate partner violence and child nutrition and mortality: findings from Demographic and Health Surveys in Egypt, Honduras, Kenya, Malawi and Rwanda.

    Science.gov (United States)

    Rico, Emily; Fenn, Bridget; Abramsky, Tanya; Watts, Charlotte

    2011-04-01

    If effective interventions are to be used to address child mortality and malnutrition, then it is important that we understand the different pathways operating within the framework of child health. More attention needs to be given to understanding the contribution of social influences such as intimate partner violence (IPV). To investigate the relationship between maternal exposure to IPV and child mortality and malnutrition using data from five developing countries. Population data from Egypt, Honduras, Kenya, Malawi and Rwanda were analysed. Logistic regression analysis was used to generate odds ratios of the associations between several categories of maternal exposure to IPV since the age of 15 and three child outcomes: under-2-year-old (U2) mortality and moderate and severe stunting (Honduras) to 46.2% (Kenya). For child stunting, prevalence ranged from 25.4% (Egypt) to 58.0% (Malawi) and for U2 mortality from 3.6% (Honduras) to 15.2% (Rwanda). In Kenya, maternal exposure to IPV was associated with higher U2 mortality (adjusted odds ratio (OR)=1.42, 95% CI 1.18 to 1.71) and child stunting (adjusted OR=1.36, 95% CI 1.16 to 1.61). In Malawi and Honduras, marginal associations were observed between IPV and severe stunting and U2 mortality, respectively, with strength of associations varying by type of violence. The relationship between IPV and U2 mortality and stunting in Kenya, Honduras and Malawi suggests that, in these countries, IPV plays a role in child malnutrition and mortality. This contributes to a growing body of evidence that broader public health benefits may be incurred if efforts to address IPV are incorporated into a wider range of maternal and child health programmes; however, the authors highlight the need for more research that can establish temporality, use data collected on the basis of the study's objectives, and further explore the causal framework of this relationship using more advanced statistical analysis.

  2. Poverty-associated risk factors for wheezing in the first year of life in Honduras and El Salvador.

    Science.gov (United States)

    Bueso, A; Figueroa, M; Cousin, L; Hoyos, W; Martínez-Torres, A E; Mallol, J; Garcia-Marcos, L

    2010-01-01

    Risk factors for wheezing specifically during the first year of life have been studied in well-developed countries, but the information from developing countries is very scarce. There are no such studies focusing on factors derived from poverty. The aim of the present study was to determine if risk factors related to poverty are associated to wheezing during the first year of life in infants from Honduras and El Salvador. A survey, using a validated questionnaire, was carried out in the metropolitan area of San Pedro Sula (Honduras) and in La Libertad (El Salvador) in centres where infants attended for a scheduled vaccination shot or a healthy child visit at 12 months of age. Fieldworkers offered questionnaires to parents and helped the illiterate when necessary. The main outcome variable was wheezing during the first year of life, as reported by parents. A total of 1047 infants in El Salvador and 780 in Honduras were included in the analysis. The prevalence of wheeze in the first year was higher in El Salvador (41.2%) than in Honduras (27.7%), as was recurrent wheezing defined as three or more episodes (18.4% vs. 11.7%). Wheezing and recurrent wheezing was associated to unpaved floor in the household (summary odds ratios for both countries 1.55, p=0.036 and 1.72, p=0.054 for any wheeze and recurrent wheezing, respectively); dust entering from streets (1.30, p=0.052 and 1.67, p=0.008); living in a heavily polluted area (1.33, p=0.037 and 1.52, p=0.033); and having mould stains on the household walls (1.36, p=0.072 and 1.76, p=0.007). Furthermore, marginal associations were found for additional person at home and use of kerosene as cooking fuel. University studies in the mother (0.34, p=0.046 and 0.32, p=0.022) and a professional occupation in the father (0.34, p=0.046 and 0.26, p=0.047) were associated to a lower risk. The prevalence of wheezing and recurrent wheezing is notoriously high in El Salvador and Honduras. In those populations factors related to poverty

  3. Modeling population dynamics of mitochondria in mammalian cells

    Science.gov (United States)

    Kornick, Kellianne; Das, Moumita

    Mitochondria are organelles located inside eukaryotic cells and are essential for several key cellular processes such as energy (ATP) production, cell signaling, differentiation, and apoptosis. All organisms are believed to have low levels of variation in mitochondrial DNA (mtDNA), and alterations in mtDNA are connected to a range of human health conditions, including epilepsy, heart failure, Parkinsons disease, diabetes, and multiple sclerosis. Therefore, understanding how changes in mtDNA accumulate over time and are correlated to changes in mitochondrial function and cell properties can have a profound impact on our understanding of cell physiology and the origins of some diseases. Motivated by this, we develop and study a mathematical model to determine which cellular parameters have the largest impact on mtDNA population dynamics. The model consists of coupled ODEs to describe subpopulations of healthy and dysfunctional mitochondria subject to mitochondrial fission, fusion, autophagy, and mutation. We study the time evolution and stability of each sub-population under specific selection biases and pressures by tuning specific terms in our model. Our results may provide insights into how sub-populations of mitochondria survive and evolve under different selection pressures. This work was supported by a Grant from the Moore Foundation.

  4. Plasmodium vivax Population Structure and Transmission Dynamics in Sabah Malaysia

    Science.gov (United States)

    Abdullah, Noor Rain; Barber, Bridget E.; William, Timothy; Norahmad, Nor Azrina; Satsu, Umi Rubiah; Muniandy, Prem Kumar; Ismail, Zakiah; Grigg, Matthew J.; Jelip, Jenarun; Piera, Kim; von Seidlein, Lorenz; Yeo, Tsin W.; Anstey, Nicholas M.; Price, Ric N.; Auburn, Sarah

    2013-01-01

    Despite significant progress in the control of malaria in Malaysia, the complex transmission dynamics of P. vivax continue to challenge national efforts to achieve elimination. To assess the impact of ongoing interventions on P. vivax transmission dynamics in Sabah, we genotyped 9 short tandem repeat markers in a total of 97 isolates (8 recurrences) from across Sabah, with a focus on two districts, Kota Marudu (KM, n = 24) and Kota Kinabalu (KK, n = 21), over a 2 year period. STRUCTURE analysis on the Sabah-wide dataset demonstrated multiple sub-populations. Significant differentiation (F ST  = 0.243) was observed between KM and KK, located just 130 Km apart. Consistent with low endemic transmission, infection complexity was modest in both KM (mean MOI  = 1.38) and KK (mean MOI  = 1.19). However, population diversity remained moderate (H E  = 0.583 in KM and H E  = 0.667 in KK). Temporal trends revealed clonal expansions reflecting epidemic transmission dynamics. The haplotypes of these isolates declined in frequency over time, but persisted at low frequency throughout the study duration. A diverse array of low frequency isolates were detected in both KM and KK, some likely reflecting remnants of previous expansions. In accordance with clonal expansions, high levels of Linkage Disequilibrium (I A S >0.5 [P<0.0001] in KK and KM) declined sharply when identical haplotypes were represented once (I A S  = 0.07 [P = 0.0076] in KM, and I A S = -0.003 [P = 0.606] in KK). All 8 recurrences, likely to be relapses, were homologous to the prior infection. These recurrences may promote the persistence of parasite lineages, sustaining local diversity. In summary, Sabah's shrinking P. vivax population appears to have rendered this low endemic setting vulnerable to epidemic expansions. Migration may play an important role in the introduction of new parasite strains leading to epidemic expansions, with important implications for malaria

  5. Can Maquila Booms Reduce Poverty? Evidence from Honduras

    OpenAIRE

    de Hoyos, Rafael E.; Bussolo, Maurizio; Nunez, Oscar

    2008-01-01

    This paper identifies and estimates the strength of the reduction in poverty linked to improved opportunities for women in the expanding maquila sector. A simulation exercise shows that, at a given point in time, poverty in Honduras would have been 1.5 percentage points higher had the maquila sector not existed. Of this increase in poverty, 0.35 percentage points is attributable to the wag...

  6. Sustainable energy policy in Honduras: Diagnosis and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Wilfredo C. [National Directorate of Energy, Tegucigalpa (MDC) (Honduras); Universidad Nacional Autonoma de Honduras, Facultad de Ciencias, Escuela de Fisica, Tegucigalpa (MDC) (Honduras); Ojeda, Osvaldo A. [Universidad Nacional de la Patagonia San Juan Bosco (Argentina); Flores, Marco A.; Rivas, Francisco R. [Universidad Nacional Autonoma de Honduras, Facultad de Ciencias, Escuela de Fisica, Tegucigalpa (MDC) (Honduras)

    2011-02-15

    In view of having a still unexploited potential of natural resources available for clean energy and the possibility of using the regional electricity market in Central America, Honduras has several potential energy sources. The growing dependence on oil and the imminent increase in international prices of fossil fuels, coupled with the necessity of changing the energy sector arrangement, the State of Honduras has taken the lead for the development of a long-term sustainable energy policy. This energy policy must be able to develop various energy sources and guide both, the government and the private sector, to the planning and development of alternative energy sources and sustainable growth of the Honduran economy. In this paper, the various energy diagnoses and the potential for changing the Honduran energy mix are presented, as well as the investment required for sustainable management of the energy sector. Furthermore, the objectives of the energy policy and plan up to the year 2030 are presented, outlining the investment possibilities for the energy sector development, showing their costs and timeframes. - Research Highlights: {yields} This paper shows the development of a long-term energy policy for Honduras. {yields} The various diagnoses of the energy sector in Honduras are shown, considering the use of wood, biomass, biofuels, electricity, transportation, hydrocarbons and rural electrification. {yields} The most relevant results of the analysis of energy forecasting are shown, for which the LEAP software was used. {yields} The objectives of the energy policy and plan up to the year 2030 are presented, outlining the investment possibilities for the energy sector development, showing their costs and timeframes.

  7. Death in the Afternoon: Honduras, Hemingway, and Duncan Strong

    Directory of Open Access Journals (Sweden)

    Thomas W. Cuddy

    2002-11-01

    Full Text Available Archaeologist William Duncan Strong and author Ernest Hemingway are both known for the exemplary works they produced in their respective fields. Most people don't know the shared similarities in the parallel lives of these two men, and the greater social forces that shaped them. This essay takes a Hemingway-like approach to the life of Duncan Strong, using excerpts from Strong's expedition to Honduras in 1933 to draw analogy with the publicly renowned life of Ernest Hemingway.

  8. Gangs in Honduras: A Threat to National Security

    Science.gov (United States)

    2012-03-22

    police, judiciary and political elites. In some parts of the country, “drug cartels act as de facto authority and there is evidence of a training camp...practical to politicians…to expect the military to solve the problem by force, nor is it practical for the military to plan and execute a purely military...Honduras: Tegucigalpa, National Defense College and El Salvador University, October 30, 2007), http://cdn.U.S.alnet.org/ tesis /files/osorio.pdf

  9. Violent Crime: A Comparative Study of Honduras and Nicaragua

    Science.gov (United States)

    2009-03-01

    franchisees , or exclusive distributors of U.S. products. The largest are in energy, financial services, apparel, manufacturing, and fisheries.”16...expected benefits greater than expected costs; (3) rational preventive war; (4) rational miscalculation due to lack of information; and (5) rational...Football War” between El Salvador and Honduras where, in this instance, both sides may have expected greater benefit than costs. This kind of war is the

  10. Mean-field games with logistic population dynamics

    KAUST Repository

    Gomes, Diogo A.

    2013-12-01

    In its standard form, a mean-field game can be defined by coupled system of equations, a Hamilton-Jacobi equation for the value function of agents and a Fokker-Planck equation for the density of agents. Traditionally, the latter equation is adjoint to the linearization of the former. Since the Fokker-Planck equation models a population dynamic, we introduce natural features such as seeding and birth, and nonlinear death rates. In this paper we analyze a stationary meanfield game in one dimension, illustrating various techniques to obtain regularity of solutions in this class of systems. In particular we consider a logistic-type model for birth and death of the agents which is natural in problems where crowding affects the death rate of the agents. The introduction of these new terms requires a number of new ideas to obtain wellposedness. In a forthcoming publication we will address higher dimensional models. ©2013 IEEE.

  11. Mean-field games with logistic population dynamics

    KAUST Repository

    Gomes, Diogo A.; De Lima Ribeiro, Ricardo

    2013-01-01

    In its standard form, a mean-field game can be defined by coupled system of equations, a Hamilton-Jacobi equation for the value function of agents and a Fokker-Planck equation for the density of agents. Traditionally, the latter equation is adjoint to the linearization of the former. Since the Fokker-Planck equation models a population dynamic, we introduce natural features such as seeding and birth, and nonlinear death rates. In this paper we analyze a stationary meanfield game in one dimension, illustrating various techniques to obtain regularity of solutions in this class of systems. In particular we consider a logistic-type model for birth and death of the agents which is natural in problems where crowding affects the death rate of the agents. The introduction of these new terms requires a number of new ideas to obtain wellposedness. In a forthcoming publication we will address higher dimensional models. ©2013 IEEE.

  12. Richards-like two species population dynamics model.

    Science.gov (United States)

    Ribeiro, Fabiano; Cabella, Brenno Caetano Troca; Martinez, Alexandre Souto

    2014-12-01

    The two-species population dynamics model is the simplest paradigm of inter- and intra-species interaction. Here, we present a generalized Lotka-Volterra model with intraspecific competition, which retrieves as particular cases, some well-known models. The generalization parameter is related to the species habitat dimensionality and their interaction range. Contrary to standard models, the species coupling parameters are general, not restricted to non-negative values. Therefore, they may represent different ecological regimes, which are derived from the asymptotic solution stability analysis and are represented in a phase diagram. In this diagram, we have identified a forbidden region in the mutualism regime, and a survival/extinction transition with dependence on initial conditions for the competition regime. Also, we shed light on two types of predation and competition: weak, if there are species coexistence, or strong, if at least one species is extinguished.

  13. Artificial bee colony algorithm with dynamic multi-population

    Science.gov (United States)

    Zhang, Ming; Ji, Zhicheng; Wang, Yan

    2017-07-01

    To improve the convergence rate and make a balance between the global search and local turning abilities, this paper proposes a decentralized form of artificial bee colony (ABC) algorithm with dynamic multi-populations by means of fuzzy C-means (FCM) clustering. Each subpopulation periodically enlarges with the same size during the search process, and the overlapping individuals among different subareas work for delivering information acting as exploring the search space with diffusion of solutions. Moreover, a Gaussian-based search equation with redefined local attractor is proposed to further accelerate the diffusion of the best solution and guide the search towards potential areas. Experimental results on a set of benchmarks demonstrate the competitive performance of our proposed approach.

  14. A paediatric cardiopulmonary resuscitation training project in Honduras.

    Science.gov (United States)

    Urbano, Javier; Matamoros, Martha M; López-Herce, Jesús; Carrillo, Angel P; Ordóñez, Flora; Moral, Ramón; Mencía, Santiago

    2010-04-01

    It is possible that the exportation of North American and European models has hindered the creation of a structured cardiopulmonary resuscitation (CPR) training programme in developing countries. The objective of this paper is to describe the design and present the results of a European paediatric and neonatal CPR training programme adapted to Honduras. A paediatric CPR training project was set up in Honduras with the instructional and scientific support of the Spanish Group for Paediatric and Neonatal CPR. The programme was divided into four phases: CPR training and preparation of instructors; training for instructors; supervised teaching; and independent teaching. During the first phase, 24 Honduran doctors from paediatric intensive care, paediatric emergency and anaesthesiology departments attended the paediatric CPR course and 16 of them the course for preparation as instructors. The Honduran Paediatric and Neonatal CPR Group was formed. In the second phase, workshops were given by Honduran instructors and four of them attended a CPR course in Spain as trainee instructors. In the third phase, a CPR course was given in Honduras by the Honduran instructors, supervised by the Spanish team. In the final phase of independent teaching, eight courses were given, providing 177 students with training in CPR. The training of independent paediatric CPR groups with the collaboration and scientific assessment of an expert group could be a suitable model on which to base paediatric CPR training in Latin American developing countries. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

  15. On the stochastic approach to marine population dynamics

    Directory of Open Access Journals (Sweden)

    Eduardo Ferrandis

    2007-03-01

    Full Text Available The purpose of this article is to deepen and structure the statistical basis of marine population dynamics. The starting point is the correspondence between the concepts of mortality, survival and lifetime distribution. This is the kernel of the possibilities that survival analysis techniques offer to marine population dynamics. A rigorous definition of survival and mortality based on their properties and their probabilistic versions is briefly presented. Some well established models for lifetime distribution, which generalise the usual simple exponential distribution, might be used with their corresponding survivals and mortalities. A critical review of some published models is also made, including original models proposed in the way opened by Caddy (1991 and Sparholt (1990, which allow for a continuously decreasing natural mortality. Considering these elements, the pure death process dealt with in the literature is used as a theoretical basis for the evolution of a marine cohort. The elaboration of this process is based on Chiang´s study of the probability distribution of the life table (Chiang, 1960 and provides specific structured models for stock evolution as a Markovian process. These models may introduce new ideas in the line of thinking developed by Gudmundsson (1987 and Sampson (1990 in order to model the evolution of a marine cohort by stochastic processes. The suitable approximation of these processes by means of Gaussian processes may allow theoretical and computational multivariate Gaussian analysis to be applied to the probabilistic treatment of fisheries issues. As a consequence, the necessary catch equation appears as a stochastic integral with respect to the mentioned Markovian process of the stock. The solution of this equation is available when the mortalities are proportional, hence the use of the proportional hazards model (Cox, 1959. The assumption of these proportional mortalities leads naturally to the construction of a

  16. Dynamical evolution of a fictitious population of binary Neptune Trojans

    Science.gov (United States)

    Brunini, Adrián

    2018-03-01

    We present numerical simulations of the evolution of a synthetic population of Binary Neptune Trojans, under the influence of the solar perturbations and tidal friction (the so-called Kozai cycles and tidal friction evolution). Our model includes the dynamical influence of the four giant planets on the heliocentric orbit of the binary centre of mass. In this paper, we explore the evolution of initially tight binaries around the Neptune L4 Lagrange point. We found that the variation of the heliocentric orbital elements due to the libration around the Lagrange point introduces significant changes in the orbital evolution of the binaries. Collisional processes would not play a significant role in the dynamical evolution of Neptune Trojans. After 4.5 × 109 yr of evolution, ˜50 per cent of the synthetic systems end up separated as single objects, most of them with slow diurnal rotation rate. The final orbital distribution of the surviving binary systems is statistically similar to the one found for Kuiper Belt Binaries when collisional evolution is not included in the model. Systems composed by a primary and a small satellite are more fragile than the ones composed by components of similar sizes.

  17. Evolutionary game dynamics in a growing structured population

    Energy Technology Data Exchange (ETDEWEB)

    Poncela, Julia; Gomez-Gardenes, Jesus; Moreno, Yamir [Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, E-50009 Zaragoza (Spain); Traulsen, Arne [Emmy-Noether Group for Evolutionary Dynamics, Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Strasse 2, 24306 Ploen (Germany)], E-mail: traulsen@evolbio.mpg.de

    2009-08-15

    We discuss a model for evolutionary game dynamics in a growing, network-structured population. In our model, new players can either make connections to random preexisting players or preferentially attach to those that have been successful in the past. The latter depends on the dynamics of strategies in the game, which we implement following the so-called Fermi rule such that the limits of weak and strong strategy selection can be explored. Our framework allows to address general evolutionary games. With only two parameters describing the preferential attachment and the intensity of selection, we describe a wide range of network structures and evolutionary scenarios. Our results show that even for moderate payoff preferential attachment, over represented hubs arise. Interestingly, we find that while the networks are growing, high levels of cooperation are attained, but the same network structure does not promote cooperation as a static network. Therefore, the mechanism of payoff preferential attachment is different to those usually invoked to explain the promotion of cooperation in static, already-grown networks.

  18. Evolutionary game dynamics in a growing structured population

    International Nuclear Information System (INIS)

    Poncela, Julia; Gomez-Gardenes, Jesus; Moreno, Yamir; Traulsen, Arne

    2009-01-01

    We discuss a model for evolutionary game dynamics in a growing, network-structured population. In our model, new players can either make connections to random preexisting players or preferentially attach to those that have been successful in the past. The latter depends on the dynamics of strategies in the game, which we implement following the so-called Fermi rule such that the limits of weak and strong strategy selection can be explored. Our framework allows to address general evolutionary games. With only two parameters describing the preferential attachment and the intensity of selection, we describe a wide range of network structures and evolutionary scenarios. Our results show that even for moderate payoff preferential attachment, over represented hubs arise. Interestingly, we find that while the networks are growing, high levels of cooperation are attained, but the same network structure does not promote cooperation as a static network. Therefore, the mechanism of payoff preferential attachment is different to those usually invoked to explain the promotion of cooperation in static, already-grown networks.

  19. An Analysis of Contraceptive Discontinuation among Female, Reversible Method Users in Urban Honduras

    Science.gov (United States)

    Barden-O’Fallon, Janine; Speizer, Ilene S.; Cálix, Javier; Rodriguez, Francisco

    2013-01-01

    A panel study examining the effects of individual characteristics, side effects experienced, and service quality on contraceptive discontinuation was undertaken in four urban areas of Honduras. Data were collected from October 2006 to December 2007. The baseline population included 800 women aged 15–44 who were new or continuing users of the injectable, IUD, or oral contraceptive pill. A total of 671 women (84%) were re-interviewed after one year. Life tables and Cox proportional hazards models are used to present discontinuation rates and factors associated with contraceptive discontinuation. Among new users, discontinuation of the baseline method at 12 months was high (45%); especially for users of the injectable (50%). In the hazards model, service quality had little effect on discontinuation, while individual characteristics and the experience of specific side effects showed significant effects. The results suggest that programs should emphasize continuous contraceptive coverage rather than continuous use of a particular method. PMID:21500697

  20. Evolutionary Dynamics of Collective Action in Structured Populations

    Science.gov (United States)

    Santos, Marta Daniela de Almeida

    The pervasiveness of cooperation in Nature is not easily explained. If evolution is characterized by competition and survival of the fittest, why should selfish individuals cooperate with each other? Evolutionary Game Theory (EGT) provides a suitable mathematical framework to study this problem, central to many areas of science. Conventionally, interactions between individuals are modeled in terms of one-shot, symmetric 2-Person Dilemmas of Cooperation, but many real-life situations involve decisions within groups with more than 2 individuals, which are best-dealt in the framework of N-Person games. In this Thesis, we investigate the evolutionary dynamics of two paradigmatic collective social dilemmas - the N-Person Prisoner's Dilemma (NPD) and the N-Person Snowdrift Game (NSG) on structured populations, modeled by networks with diverse topological properties. Cooperative strategies are just one example of the many traits that can be transmitted on social networks. Several recent studies based on empirical evidence from a medical database have suggested the existence of a 3 degrees of influence rule, according to which not only our "friends", but also our friends' friends, and our friends' friends' friends, have a non-trivial influence on our decisions. We investigate the degree of peer influence that emerges from the spread of cooperative strategies, opinions and diseases on populations with distinct underlying networks of contacts. Our results show that networks naturally entangle individuals into interactions of many-body nature and that for each network class considered different processes lead to identical degrees of influence. None

  1. Population dynamics of Vibrio fischeri during infection of Euprymna scolopes.

    Science.gov (United States)

    McCann, Jessica; Stabb, Eric V; Millikan, Deborah S; Ruby, Edward G

    2003-10-01

    The luminous bacterium Vibrio fischeri colonizes a specialized light-emitting organ within its squid host, Euprymna scolopes. Newly hatched juvenile squid must acquire their symbiont from ambient seawater, where the bacteria are present at low concentrations. To understand the population dynamics of V. fischeri during colonization more fully, we used mini-Tn7 transposons to mark bacteria with antibiotic resistance so that the growth of their progeny could be monitored. When grown in culture, there was no detectable metabolic burden on V. fischeri cells carrying the transposon, which inserts in single copy in a specific intergenic region of the V. fischeri genome. Strains marked with mini-Tn7 also appeared to be equivalent to the wild type in their ability to infect and multiply within the host during coinoculation experiments. Studies of the early stages of colonization suggested that only a few bacteria became associated with symbiotic tissue when animals were exposed for a discrete period (3 h) to an inoculum of V. fischeri cells equivalent to natural population levels; nevertheless, all these hosts became infected. When three differentially marked strains of V. fischeri were coincubated with juvenile squid, the number of strains recovered from an individual symbiotic organ was directly dependent on the size of the inoculum. Further, these results indicated that, when exposed to low numbers of V. fischeri, the host may become colonized by only one or a few bacterial cells, suggesting that symbiotic infection is highly efficient.

  2. Effects of constant immigration on the dynamics and persistence of stable and unstable Drosophila populations

    Science.gov (United States)

    Dey, Snigdhadip; Joshi, Amitabh

    2013-01-01

    Constant immigration can stabilize population size fluctuations but its effects on extinction remain unexplored. We show that constant immigration significantly reduced extinction in fruitfly populations with relatively stable or unstable dynamics. In unstable populations with oscillations of amplitude around 1.5 times the mean population size, persistence and constancy were unrelated. Low immigration enhanced persistence without affecting constancy whereas high immigration increased constancy without enhancing persistence. In relatively stable populations with erratic fluctuations of amplitude close to the mean population size, both low and high immigration enhanced persistence. In these populations, the amplitude of fluctuations relative to mean population size went down due to immigration, and their dynamics were altered to low-period cycles. The effects of immigration on the population size distribution and intrinsic dynamics of stable versus unstable populations differed considerably, suggesting that the mechanisms by which immigration reduced extinction risk depended on underlying dynamics in complex ways. PMID:23470546

  3. Population dynamics of caribou herds in southwestern Alaska

    Directory of Open Access Journals (Sweden)

    Patrick Valkenburg

    2003-04-01

    Full Text Available The five naturally occurring and one transplanted caribou (Rangifer tarandus granti herd in southwestern Alaska composed about 20% of Alaska's caribou population in 2001. All five of the naturally occurring herds fluctuated considerably in size between the late 1800s and 2001 and for some herds the data provide an indication of long-term periodic (40-50 year fluctuations. At the present time, the Unimak (UCH and Southern Alaska Peninsula (SAP are recovering from population declines, the Northern Alaska Peninsula Herd (NAP appears to be nearing the end of a protracted decline, and the Mulchatna Herd (MCH appears to now be declining after 20 years of rapid growth. The remaining naturally occurring herd (Kilbuck has virtually disappeared. Nutrition had a significant effect on the size of 4-month-old and 10-month-old calves in the NAP and the Nushagak Peninsula Herd (NPCH and probably also on population growth in at least 4 (SAP, NAP, NPCH, and MCH of the six caribou herds in southwestern Alaska. Predation does not appear to be sufficient to keep caribou herds in southwestern Alaska from expanding, probably because rabies is endemic in red foxes (Vulpes vulpes and is periodically transferred to wolves (Canis lupus and other canids. However, we found evidence that pneumonia and hoof rot may result in significant mortality of caribou in southwestern Alaska, whereas there is no evidence that disease is important in the dynamics of Interior herds. Cooperative conservation programs, such as the Kilbuck Caribou Management Plan, can be successful in restraining traditional harvest and promoting growth in caribou herds. In southwestern Alaska we also found evidence that small caribou herds can be swamped and assimilated by large herds, and fidelity to traditional calving areas can be lost.

  4. Modelling multi-pulse population dynamics from ultrafast spectroscopy.

    Directory of Open Access Journals (Sweden)

    Luuk J G W van Wilderen

    2011-03-01

    Full Text Available Current advanced laser, optics and electronics technology allows sensitive recording of molecular dynamics, from single resonance to multi-colour and multi-pulse experiments. Extracting the occurring (bio- physical relevant pathways via global analysis of experimental data requires a systematic investigation of connectivity schemes. Here we present a Matlab-based toolbox for this purpose. The toolbox has a graphical user interface which facilitates the application of different reaction models to the data to generate the coupled differential equations. Any time-dependent dataset can be analysed to extract time-independent correlations of the observables by using gradient or direct search methods. Specific capabilities (i.e. chirp and instrument response function for the analysis of ultrafast pump-probe spectroscopic data are included. The inclusion of an extra pulse that interacts with a transient phase can help to disentangle complex interdependent pathways. The modelling of pathways is therefore extended by new theory (which is included in the toolbox that describes the finite bleach (orientation effect of single and multiple intense polarised femtosecond pulses on an ensemble of randomly oriented particles in the presence of population decay. For instance, the generally assumed flat-top multimode beam profile is adapted to a more realistic Gaussian shape, exposing the need for several corrections for accurate anisotropy measurements. In addition, the (selective excitation (photoselection and anisotropy of populations that interact with single or multiple intense polarised laser pulses is demonstrated as function of power density and beam profile. Using example values of real world experiments it is calculated to what extent this effectively orients the ensemble of particles. Finally, the implementation includes the interaction with multiple pulses in addition to depth averaging in optically dense samples. In summary, we show that mathematical

  5. Modelling multi-pulse population dynamics from ultrafast spectroscopy.

    Science.gov (United States)

    van Wilderen, Luuk J G W; Lincoln, Craig N; van Thor, Jasper J

    2011-03-21

    Current advanced laser, optics and electronics technology allows sensitive recording of molecular dynamics, from single resonance to multi-colour and multi-pulse experiments. Extracting the occurring (bio-) physical relevant pathways via global analysis of experimental data requires a systematic investigation of connectivity schemes. Here we present a Matlab-based toolbox for this purpose. The toolbox has a graphical user interface which facilitates the application of different reaction models to the data to generate the coupled differential equations. Any time-dependent dataset can be analysed to extract time-independent correlations of the observables by using gradient or direct search methods. Specific capabilities (i.e. chirp and instrument response function) for the analysis of ultrafast pump-probe spectroscopic data are included. The inclusion of an extra pulse that interacts with a transient phase can help to disentangle complex interdependent pathways. The modelling of pathways is therefore extended by new theory (which is included in the toolbox) that describes the finite bleach (orientation) effect of single and multiple intense polarised femtosecond pulses on an ensemble of randomly oriented particles in the presence of population decay. For instance, the generally assumed flat-top multimode beam profile is adapted to a more realistic Gaussian shape, exposing the need for several corrections for accurate anisotropy measurements. In addition, the (selective) excitation (photoselection) and anisotropy of populations that interact with single or multiple intense polarised laser pulses is demonstrated as function of power density and beam profile. Using example values of real world experiments it is calculated to what extent this effectively orients the ensemble of particles. Finally, the implementation includes the interaction with multiple pulses in addition to depth averaging in optically dense samples. In summary, we show that mathematical modelling is

  6. Bilateral Agreement for Military Assistance between the Government of Honduras and the Government of the United States

    Science.gov (United States)

    2013-06-13

    CIENCIAS Y ARTES MILITARES Estudios Generales Por...OTHONIEL GROSS, MAYOR DEL EJÉRCITO DE HONDURAS. Licenciado en Ciencias Militares, Universidad de Defensa de Honduras, Honduras, 2010 Fuerte Leavenworth...Z39.18 ii MAESTRÍA EN CIENCIAS

  7. Hurricane Mitch: Peak Discharge for Selected River Reachesin Honduras

    Science.gov (United States)

    Smith, Mark E.; Phillips, Jeffrey V.; Spahr, Norman E.

    2002-01-01

    Hurricane Mitch began as a tropical depression in the Caribbean Sea on 22 October 1998. By 26 October, Mitch had strengthened to a Category 5 storm as defined by the Saffir-Simpson Hurricane Scale (National Climate Data Center, 1999a), and on 27 October was threatening the northern coast of Honduras (fig. 1). After making landfall 2 days later (29 October), the storm drifted south and west across Honduras, wreaking destruction throughout the country before reaching the Guatemalan border on 31 October. According to the National Climate Data Center of the National Oceanic and Atmospheric Administration (National Climate Data Center, 1999b), Hurricane Mitch ranks among the five strongest storms on record in the Atlantic Basin in terms of its sustained winds, barometric pressure, and duration. Hurricane Mitch also was one of the worst Atlantic storms in terms of loss of life and property. The regionwide death toll was estimated to be more than 9,000; thousands of people were reported missing. Economic losses in the region were more than $7.5 billion (U.S. Agency for International Development, 1999). Honduras suffered the most widespread devastation during the storm. More than 5,000 deaths, and economic losses of more than $4 billion, were reported by the Government of Honduras. Honduran officials estimated that Hurricane Mitch destroyed 50 years of economic development. In addition to the human and economic losses, intense flooding and landslides scarred the Honduran landscape - hydrologic and geomorphologic processes throughout the country likely will be affected for many years. As part of the U.S. Government's response to the disaster, the U.S. Geological Survey (USGS) conducted post-flood measurements of peak discharge at 16 river sites throughout Honduras (fig. 2). Such measurements, termed 'indirect' measurements, are used to determine peak flows when direct measurements (using current meters or dye studies, for example) cannot be made. Indirect measurements of

  8. Phase control of light amplification with dynamically irreversible pathways of population transfer in a Λ system

    International Nuclear Information System (INIS)

    Yuan Shi; Wu Jinhui; Gao Jinyue; Pan Chunliu

    2002-01-01

    We use the relative phase of two coherent fields for the control of light amplification with dynamically irreversible pathways of population transfer in a Λ system. The population inversion and gain with dynamically irreversible pathways of population transfer are shown as the relative phase is varied. We support our results by numerical calculation and analytical explanation

  9. Analisis de las Condiciones de Salud del Nino de 0-6 anos en Honduras.

    Science.gov (United States)

    Matamoros, Douglas Alberto

    1987-01-01

    Examines the National Pediatric Service and the research program of the Maternity-Infant-Hospital-School in Honduras. Reports that health conditions of young children (birth to six years) in Honduras are appalling and that available funds for health services are inadequate, reflecting the country's economic and social crisis. (NH)

  10. Chlamydia trachomatis and genital human papillomavirus infections in female university students in Honduras.

    NARCIS (Netherlands)

    Tabora, N.; Zelaya, A.; Bakkers, J.; Melchers, W.J.; Ferrera, A.

    2005-01-01

    Sexually transmitted infections are a serious health problem in Honduras. Human papillomavirus (HPV) and Chlamydia trachomatis are major causes of sexually transmitted diseases. To determine the prevalence of C. trachomatis and HPV in young women, 100 female university students in Honduras were

  11. Educational Facility Evaluations of Primary Schools in Rural Honduras: Departments of Cortes and Meambar.

    Science.gov (United States)

    Council of Educational Facility Planners, International, Scottsdale, AZ.

    A team of 11 educational facility planners and architects from the United States and Canada conducted a facility evaluation of schools in the rural areas of Meambar and Cortes, Honduras. Team members were all part of the Council of Educational Facility Planners, International and traveled to Honduras under the auspices of a Christian mission…

  12. Population dynamics in the high Arctic: Climate variations in time and space

    DEFF Research Database (Denmark)

    Hendrichsen, Ditte Katrine

    Climatic factors profoundly influence the population dynamics, species interactions and demography of Arctic species. Analyses of the spatio-temporal dynamics within and across species are therefore necessary to understand and predict the responses of Arctic ecosystems to climatic variability...

  13. Population dynamics of Borrelia burgdorferi in Lyme disease

    Directory of Open Access Journals (Sweden)

    Sebastian Christoph Binder

    2012-03-01

    Full Text Available Many chronic inflammatory diseases are known to be caused by persistent bacterial or viral infections. A well-studied example is the tick-borne infection by the gram-negative Spirochaetes of the genus Borrelia in humans and other mammals, causing severe symptoms of chronic inflammation and subsequent tissue damage (Lyme Disease, particularly in large joints and the central nervous system, but also in the heart and other tissues of untreated patients. Although killed efficiently by human phagocytic cells in vitro, Borrelia exhibits a remarkably high infectivity in mice and men. In experimentally infected mice, the first immune response almost clears the infection. However, approximately one week post infection, the bacterial population recovers and reaches an even larger size before entering the chronic phase. We developed a mathematical model describing the bacterial growth and the immune response against Borrelia burgdorferi in the C3H mouse strain that has been established as an experimental model for Lyme disease. The peculiar dynamics of the infection exclude two possible mechanistic explanations for the regrowth of the almost cleared bacteria. Neither the hypothesis of bacterial dissemination to different tissue nor a limitation of phagocytic capacity were compatible with experiment. The mathematical model predicts that Borrelia recovers from the strong initial immune response by the regrowth of an immune-resistant sub-population of the bacteria. The chronic phase appears as an equilibration of bacterial growth and adaptive immunity. This result has major implications for the development of the chronic phase of Borrelia infections as well as on potential protective clinical interventions.

  14. Impact of climate change on fish population dynamics in the baltic sea: a dynamical downscaling investigation

    DEFF Research Database (Denmark)

    Mackenzie, Brian R; Meier, H E Markus; Lindegren, Martin

    2012-01-01

    Understanding how climate change, exploitation and eutrophication will affect populations and ecosystems of the Baltic Sea can be facilitated with models which realistically combine these forcings into common frameworks. Here, we evaluate sensitivity of fish recruitment and population dynamics...... and the temperature have influenced recruitment for at least 50 years. The three Baltic Sea models estimate relatively similar developments (increases) in biomass and fishery yield during twenty-first century climate change (ca. 28 % range among models). However, this uncertainty is exceeded by the one associated...... to past and future environmental forcings provided by three ocean-biogeochemical models of the Baltic Sea. Modeled temperature explained nearly as much variability in reproductive success of sprat (Sprattus sprattus; Clupeidae) as measured temperatures during 1973-2005, and both the spawner biomass...

  15. Population dynamics and monitoring applied to decision-making

    Directory of Open Access Journals (Sweden)

    Conroy, M. J.

    2004-06-01

    influence diagrams to capture the stochastic, temporal processes of managing cheetah population in Kenya. The model predicts likely anagement decisions made by various actors within these countries, (e.g., the President, the Environmental Protection Agency, and rural residents and the resulting probability of cheetah extinction following these decisions. By approaching the problem in both its political and ecological contexts one avoids consideration of decisions that, while beneficial from a purely conservation point of view, are unlikely to be implemented because of conflicting political objectives. Haas’s analysis demonstrates both the promise and challenges of this type of modeling, and he offers suggestions for overcoming inherent technical difficulties such as model calibration. The second paper, by Simon Hoyle and Mark Maunder (Hoyle & Maunder, 2004, uses a Bayesian approach to model population dynamics and the effects of commercial fishing bycatch for the eastern Pacific Ocean spotted dolphin (Stenella attenuata. Their paper provides a good example of why Bayesian analysis is particularly suited to many management problems. Namely, because it allows the integration of disparate pieces of monitoring data in the simultaneous estimation of population parameters; allows forincorporation of expert judgment and data from other systems and species; and provides for explicit consideration of uncertainty in decision–making. Alternative management scenarios can then be explored via forward simulations. In the third paper, Chris Fonnesbeck and Mike Conroy (Fonnesbeck & Conroy, 2004 present an integrated approach for estimating parameters and predicting abundance of American black duck (Anas rubripes populations. They also employ a ayesian approach and overcome some of the computational challenges by using Markov chain–Monte Carlo methods. Ring–recovery and harvest data are used to estimate fall age ratios under alternative reproductive models. These in turn are used to

  16. Intertidal population genetic dynamics at a microgeographic seascape scale.

    Science.gov (United States)

    Hu, Zi-Min

    2013-06-01

    The intertidal community is among the most physically harsh niches on earth, with highly heterogeneous environmental and biological factors that impose strong habitat selection on population abundance, genetic connectivity and ecological adaptation of organisms in nature. However, most genetic studies to date have concentrated on the influence of basin-wide or regional marine environments (e.g. habitat discontinuities, oceanic currents and fronts, and geographic barriers) on spatiotemporal distribution and composition of intertidal invertebrates having planktonic stages or long-distance dispersal capability. Little is known about sessile marine organisms (e.g. seaweeds) in the context of topographic tidal gradients and reproductive traits at the microgeographic scale. In this issue of Molecular Ecology, Krueger-Hadfield et al. () implemented an elaborate sampling strategy with red seaweed (Chondrus crispus) from a 90-m transect stand near Roscoff and comprehensively detected genome-scale genetic differentiation and biases in ploidy level. This study not only revealed that tidal height resulted in genetic differentiation between high- and low-shore stands and restricted the genetic exchange within the high-shore habitat, but also demonstrated that intergametophytic nonrandom fertilization in C. crispus can cause significant deviation from Hardy-Weinberg equilibrium. Such new genetic insights highlight the importance of microgeographic genetic dynamics and life history characteristics for better understanding the evolutionary processes of speciation and diversification of intertidal marine organisms. © 2013 John Wiley & Sons Ltd.

  17. Prevalence of pfhrp2 and pfhrp3 gene deletions in Puerto Lempira, Honduras.

    Science.gov (United States)

    Abdallah, Joseph F; Okoth, Sheila Akinyi; Fontecha, Gustavo A; Torres, Rosa Elena Mejia; Banegas, Engels I; Matute, María Luisa; Bucheli, Sandra Tamara Mancero; Goldman, Ira F; de Oliveira, Alexandre Macedo; Barnwell, John W; Udhayakumar, Venkatachalam

    2015-01-21

    Recent studies have demonstrated the deletion of the histidine-rich protein 2 (PfHRP2) gene (pfhrp2) in field isolates of Plasmodium falciparum, which could result in false negative test results when PfHRP2-based rapid diagnostic tests (RDTs) are used for malaria diagnosis. Although primary diagnosis of malaria in Honduras is determined based on microscopy, RDTs may be useful in remote areas. In this study, it was investigated whether there are deletions of the pfhrp2, pfhrp3 and their respective flanking genes in 68 P. falciparum parasite isolates collected from the city of Puerto Lempira, Honduras. In addition, further investigation considered the possible correlation between parasite population structure and the distribution of these gene deletions by genotyping seven neutral microsatellites. Sixty-eight samples used in this study, which were obtained from a previous chloroquine efficacy study, were utilized in the analysis. All samples were genotyped for pfhrp2, pfhrp3 and flanking genes by PCR. The samples were then genotyped for seven neutral microsatellites in order to determine the parasite population structure in Puerto Lempira at the time of sample collection. It was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8. However, only 50% of the samples were positive for pfhrp3 and its neighboring genes while the rest were either pfhrp3-negative only or had deleted a combination of pfhrp3 and its neighbouring genes on chromosome 13. Population structure analysis predicted that there are at least two distinct parasite population clusters in this sample population. It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other. The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however

  18. Population dynamics of potato cyst nematodes and associated damage to potato

    NARCIS (Netherlands)

    Schans, J.

    1993-01-01

    Population dynamics of potato cyst nematodes (PCN; Globoderarostochiensis (Woll.) Skarbilovich and G. pallida Stone) and their interactions with potato plants are insufficiently understood to explain variations of population

  19. A spatial ecosystem and populations dynamics model (SEAPODYM) Modeling of tuna and tuna-like populations

    Science.gov (United States)

    Lehodey, Patrick; Senina, Inna; Murtugudde, Raghu

    2008-09-01

    An enhanced version of the spatial ecosystem and population dynamics model SEAPODYM is presented to describe spatial dynamics of tuna and tuna-like species in the Pacific Ocean at monthly resolution over 1° grid-boxes. The simulations are driven by a bio-physical environment predicted from a coupled ocean physical-biogeochemical model. This new version of SEAPODYM includes expanded definitions of habitat indices, movements, and natural mortality based on empirical evidences. A thermal habitat of tuna species is derived from an individual heat budget model. The feeding habitat is computed according to the accessibility of tuna predator cohorts to different vertically migrating and non-migrating micronekton (mid-trophic) functional groups. The spawning habitat is based on temperature and the coincidence of spawning fish with presence or absence of predators and food for larvae. The successful larval recruitment is linked to spawning stock biomass. Larvae drift with currents, while immature and adult tuna can move of their own volition, in addition to being advected by currents. A food requirement index is computed to adjust locally the natural mortality of cohorts based on food demand and accessibility to available forage components. Together these mechanisms induce bottom-up and top-down effects, and intra- (i.e. between cohorts) and inter-species interactions. The model is now fully operational for running multi-species, multi-fisheries simulations, and the structure of the model allows a validation from multiple data sources. An application with two tuna species showing different biological characteristics, skipjack ( Katsuwonus pelamis) and bigeye ( Thunnus obesus), is presented to illustrate the capacity of the model to capture many important features of spatial dynamics of these two different tuna species in the Pacific Ocean. The actual validation is presented in a companion paper describing the approach to have a rigorous mathematical parameter optimization

  20. Patterns and predictors of current cigarette smoking in women and men of reproductive age-Ecuador, El Salvador, Guatemala, and Honduras.

    Science.gov (United States)

    Tong, Van T; Turcios-Ruiz, Reina M; Dietz, Patricia M; England, Lucinda J

    2011-09-01

    To estimate smoking prevalence by gender, describe patterns of cigarette use, and identify predictors of current smoking in reproductive-age adults in four Latin American countries. Self-reported smoking was examined using data from Reproductive Health Surveys of women aged 15-49 years in Ecuador (2004), El Salvador (2002-2003), Guatemala (2002), and Honduras (2001), and of men aged 15-59 years in El Salvador, Guatemala, and Honduras for the same years. Current smoking was assessed by demographic characteristics, and independent associations were examined using logistic regression. Data were weighted to be nationally representative of households with reproductive-age women and men. Current smoking prevalence ranged from 2.6% (Guatemala) to 13.1% (Ecuador) for women and from 23.1% (Guatemala) to 34.9% (El Salvador) for men. In Ecuador, 67.6% of female smokers were non-daily users; in other countries, daily use was more prevalent than non-daily use for both men and women. In daily users, the median number of cigarettes smoked per day ranged from 1.9 (Ecuador, Honduras) to 2.3 (Guatemala) for women and from 2.1 (Guatemala) to 3.6 (Honduras) for men. In bivariate analysis, smoking prevalence in all countries was highest in women who lived in urban areas, were previously married, and/or had high socioeconomic status. Risk factors for smoking varied by country and gender. National tobacco control programs in these countries should aggressively target high-risk populations (reproductive-age men) and maintain low prevalence in low-risk populations (reproductive-age women). More research is needed to understand addiction patterns in non-daily smokers.

  1. Heat flow at the Platanares, Honduras, geothermal site

    Science.gov (United States)

    Meert, Joseph G.; Smith, Douglas L.

    1991-03-01

    Three boreholes, PLTG-1, PLTG-2 and PLTG-3, were drilled in the Platanares, Honduras geothermal system to evaluate the geothermal energy potential of the site. The maximum reservoir temperature was previously estimated at 225-240°C using various types of chemical and isotopic geothermometry. Geothermal gradients of 139-239°C/km, calculated from two segments of the temperature-depth profile for borehole PLTG-2, were used to project a minimum depth to the geothermal reservoir of 1.2-1.7 km. Borehole PLTG-1 exhibited an erratic temperature distribution attributed to fluid movement through a series of isolated horizontal and subhorizontal fractures. The maximum measured temperature in borehole PLTG-1 was 150.4°C, and in PLTG-2 the maximum measured temperature was 104.3°C. PLTG-3 was drilled after this study and the maximum recorded temperature of 165°C is similar to the temperature encountered in PLTG-1. Heat flow values of 392 mWm -2 and 266 mWm -2 represent the first directly-measured heat flow values for Honduras and northen Central America. Radioactive heat generation, based on gamma-ray analyses of uranium, thorium and potassium in five core samples, is less than 2.0 μWm -3 and does not appear to be a major source of the high heat flow. Several authors have proposed a variety of extensional tectonic environments for western Honduras and these heat flow values, along with published estimates of heat flow, are supportive of this type of tectonic regime.

  2. Effects of demographic structure on key properties of stochastic density-independent population dynamics.

    Science.gov (United States)

    Vindenes, Yngvild; Sæther, Bernt-Erik; Engen, Steinar

    2012-12-01

    The development of stochastic demography has largely been based on age structured populations, although other types of demographic structure, especially permanent and dynamic heterogeneity, are likely common in natural populations. The combination of stochasticity and demographic structure is a challenge for analyses of population dynamics and extinction risk, because the population structure will fluctuate around the stable structure and the population size shows transient fluctuations. However, by using a diffusion approximation for the total reproductive value, density-independent dynamics of structured populations can be described with only three population parameters: the expected population growth rate, the environmental variance and the demographic variance. These parameters depend on population structure via the state-specific vital rates and transition rates. Once they are found, the diffusion approximation represents a substantial reduction in model complexity. Here, we review and compare the key population parameters across a wide range of demographic structure, from the case of no structure to the most general case of dynamic heterogeneity, and for both discrete and continuous types. We focus on the demographic variance, but also show how environmental stochasticity can be included. This study brings together results from recent models, each considering a specific type of population structure, and places them in a general framework for structured populations. Comparison across different types of demographic structure reveals that the reproductive value is an essential concept for understanding how population structure affects stochastic dynamics and extinction risk. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Population Dynamics and Cost-Benefit Analysis. An Attempt to Relate Population Dynamics via Lifetime Reproductive Success to Short-Term Decisions

    NARCIS (Netherlands)

    Tinbergen, J.M.; Balen, J.H. van; Drent, P.J.; Cavé, A.J.; Mertens, J.A.L.; Boer-Hazewinkel, J. den

    1987-01-01

    1. The aim of this article is to explore whether cost-benefit analysis of behaviour may help to understand the population dynamics of a species. The Great Tit is taken as an example. 2. The lifetime reproductive success in different populations of Great Tits amounts from 0.7 (Hoge Veluwe, Wytham) to

  4. Metastable states and quasicycles in a stochastic Wilson-Cowan model of neuronal population dynamics

    KAUST Repository

    Bressloff, Paul C.

    2010-01-01

    We analyze a stochastic model of neuronal population dynamics with intrinsic noise. In the thermodynamic limit N→∞, where N determines the size of each population, the dynamics is described by deterministic Wilson-Cowan equations. On the other hand

  5. Geographic coupling of juvenile and adult habitat shapes spatial population dynamics of a coral reef fish

    NARCIS (Netherlands)

    Huijbers, C.M.; Nagelekerken, I.; Debrot, A.O.; Jongejans, E.

    2013-01-01

    Marine spatial population dynamics are often addressed with a focus on larval dispersal, without taking into account movement behavior of individuals in later life stages. Processes occurring during demersal life stages may also drive spatial population dynamics if habitat quality is perceived

  6. Effective population size and evolutionary dynamics in outbred ...

    Indian Academy of Sciences (India)

    populations of fruit flies is not primarily driven by new mutations, but rather by changes in the frequency of ..... Drift simulation: The sex ratio, total population size and ...... Gillespie J. H. 1994a Substitution processes in molecular evolution. II.

  7. On the apllication of single specie dynamic population model | Iguda ...

    African Journals Online (AJOL)

    The Method of mathematical models of Malthus and Verhults were applied on ten years data collected from Magaram Poultry Farm to determine the nature of population growth, population decay or constant ... Keywords: Birth rate, sustainable population, overcrowding, harvesting, independent t-test and one way Anova.

  8. Perceptions of stakeholders about nontraditional cookstoves in Honduras

    International Nuclear Information System (INIS)

    Ramirez, Sebastian; Bailis, Robert; Ghilardi, Adrian; Dwivedi, Puneet

    2012-01-01

    We used SWOT-AHP (strengths, weaknesses, opportunities and threats–analytical hierarchy process) technique to measure perceptions of four stakeholder groups: employees, local promoters, community leaders and end-users, about a nontraditional cookstove (NTCS) in Honduras. These stakeholder groups are part of an ongoing NTCS dissemination project led by Proyecto Mirador. We found that all stakeholder groups have a positive perception about the existing NTCS. Employees and local promoters stakeholder groups share similar perceptions. Smokeless cooking was selected as a prime strength, closely followed by reduction in forest logging and greenhouse gas emissions by all stakeholder groups. Availability of financial resources and responsible management were identified as crucial opportunities. Time spent in wood preparation and NTCS maintenance were identified as principal weaknesses. A long waiting time between a request and installation of NTCS and the risk of losing existing financial resources were acknowledged as major threats. Design improvements that can reduce maintenance and wood preparation time, a secure long-term source of funding through a market mechanism or direct/indirect government involvement, and early execution of pending orders will help in increasing adoption of NTCSs in rural Honduras. (letter)

  9. Sustainable energy policy in Honduras. Diagnosis and challenges

    International Nuclear Information System (INIS)

    Flores, Wilfredo C.; Ojeda, Osvaldo A.; Flores, Marco A.; Rivas, Francisco R.

    2011-01-01

    In view of having a still unexploited potential of natural resources available for clean energy and the possibility of using the regional electricity market in Central America, Honduras has several potential energy sources. The growing dependence on oil and the imminent increase in international prices of fossil fuels, coupled with the necessity of changing the energy sector arrangement, the State of Honduras has taken the lead for the development of a long-term sustainable energy policy. This energy policy must be able to develop various energy sources and guide both, the government and the private sector, to the planning and development of alternative energy sources and sustainable growth of the Honduran economy. In this paper, the various energy diagnoses and the potential for changing the Honduran energy mix are presented, as well as the investment required for sustainable management of the energy sector. Furthermore, the objectives of the energy policy and plan up to the year 2030 are presented, outlining the investment possibilities for the energy sector development, showing their costs and timeframes. (author)

  10. Developing a longitudinal cancer nursing education program in Honduras.

    Science.gov (United States)

    Sheldon, Lisa Kennedy; Wise, Barbara; Carlson, Julie R; Dowds, Cynthia; Sarchet, Vanessa; Sanchez, Jose Angel

    2013-12-01

    The present paper is a longitudinal study which aims to develop and deliver cancer nursing education conferences in Honduras using volunteer nurse educators. This program intends to (1) perform site assessments of work environments and resources for cancer care in Honduras, (2) develop cancer nursing education programs, (3) survey conference participants continuing education needs, (4) deliver cancer nursing education conferences, and (5) share data with local and global partners for future cancer programs. The study draws on a longitudinal program development with site assessments, data collection, and educational conferences at two time points. Assessments and surveys were used for conference development and delivery by volunteer nurse educators. Site assessments and conferences were delivered twice. Data were collected regarding assessments and surveys to inform program development. Survey data revealed that 65 % had internet access. Participants desired more information about handling of chemotherapy, symptom management, and palliative care. Volunteer nurse educators perform site assessments and develop educational programming for cancer nurses. Local and global partners should explore internet-based programs between site visits to create sustainable education programs.

  11. New geochemical investigations in Platanares and Azacualpa geothermal sites (Honduras)

    Science.gov (United States)

    Barberi, Franco; Carapezza, Maria Luisa; Cioni, Roberto; Lelli, Matteo; Menichini, Matia; Ranaldi, Massimo; Ricci, Tullio; Tarchini, Luca

    2013-05-01

    Platanares and Azacualpa geothermal sites of Honduras are located in an inner part of the Caribbean Plate far from the active volcanic front of Central America. Here geology indicates that there are not the conditions for the occurrence of shallow magmatic heat sources for high-enthalpy geothermal resources. Geothermal perspectives are related to the possibility of a deep circulation of meteoric water along faults and the storage of the heated fluid in fractured permeable reservoirs. Geochemical geothermometers indicate a temperature for the deeper part of the geothermal reservoir close to 200 °C for Platanares and of 150-170 °C for Azacualpa. Calcite scaling, with subordinate silica deposition has to be expected in both sites. CO2 soil flux investigations have been carried out in both areas and reveal the presence of positive anomalies likely corresponding to the presence at depth of fractured degassing geothermal reservoirs. Compared with the geothermal areas of Central Italy whose reservoirs are hosted in carbonate rocks, e.g. Latera (Chiodini et al., 2007), the CO2 soil flux measured in Honduras is significantly lower (mean of 17 g/m2day at Platanares and of 163 g/m2day at Azacualpa) probably because of the dominant silicate nature of the deep reservoirs.

  12. Sustainable energy policy in Honduras. Diagnosis and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Wilfredo C. [National Directorate of Energy, Tegucigalpa (MDC), Honduras, Central America (United States); Universidad Nacional Autonoma de Honduras, Facultad de Ciencias, Escuela de Fisica, Tegucigalpa (MDC), Honduras, Central America (United States); Ojeda, Osvaldo A. [Universidad Nacional de la Patagonia San Juan Bosco (Argentina); Flores, Marco A.; Rivas, Francisco R. [Universidad Nacional Autonoma de Honduras, Facultad de Ciencias, Escuela de Fisica, Tegucigalpa (MDC), Honduras, Central America (United States)

    2011-02-15

    In view of having a still unexploited potential of natural resources available for clean energy and the possibility of using the regional electricity market in Central America, Honduras has several potential energy sources. The growing dependence on oil and the imminent increase in international prices of fossil fuels, coupled with the necessity of changing the energy sector arrangement, the State of Honduras has taken the lead for the development of a long-term sustainable energy policy. This energy policy must be able to develop various energy sources and guide both, the government and the private sector, to the planning and development of alternative energy sources and sustainable growth of the Honduran economy. In this paper, the various energy diagnoses and the potential for changing the Honduran energy mix are presented, as well as the investment required for sustainable management of the energy sector. Furthermore, the objectives of the energy policy and plan up to the year 2030 are presented, outlining the investment possibilities for the energy sector development, showing their costs and timeframes. (author)

  13. Perceptions of stakeholders about nontraditional cookstoves in Honduras

    Science.gov (United States)

    Ramirez, Sebastian; Dwivedi, Puneet; Bailis, Robert; Ghilardi, Adrian

    2012-12-01

    We used SWOT-AHP (strengths, weaknesses, opportunities and threats-analytical hierarchy process) technique to measure perceptions of four stakeholder groups: employees, local promoters, community leaders and end-users, about a nontraditional cookstove (NTCS) in Honduras. These stakeholder groups are part of an ongoing NTCS dissemination project led by Proyecto Mirador. We found that all stakeholder groups have a positive perception about the existing NTCS. Employees and local promoters stakeholder groups share similar perceptions. Smokeless cooking was selected as a prime strength, closely followed by reduction in forest logging and greenhouse gas emissions by all stakeholder groups. Availability of financial resources and responsible management were identified as crucial opportunities. Time spent in wood preparation and NTCS maintenance were identified as principal weaknesses. A long waiting time between a request and installation of NTCS and the risk of losing existing financial resources were acknowledged as major threats. Design improvements that can reduce maintenance and wood preparation time, a secure long-term source of funding through a market mechanism or direct/indirect government involvement, and early execution of pending orders will help in increasing adoption of NTCSs in rural Honduras.

  14. Humanitarian power : Canadian electrical techies help hurricane relief in Honduras

    International Nuclear Information System (INIS)

    Mallett, N.

    1999-01-01

    A review of the emergency assistance provided to Honduras by Canada following Hurricane Mitch that struck the country with a ferocity not seen in 200 years, was described. Thousands of Hondurans were killed and three million were left homeless as vast regions of the country were literally washed away. The secondary effects of the storm - famine and disease - set in to claim even more lives. The Canadian Forces' Disaster Response Team (DART) was dispatched to conduct emergency relief operations for up to 40 days in order to bridge the gap until members of the international community arrive to provide long-term help. DART focused on providing medical care, clean drinking water, an engineering capability, and reliable communications. The medical team consisting of a small field hospital with a staff of 45 provided care for up to 500 outpatients and 30 inpatients daily, depending on the severity of injuries. The engineering team of about 40 provided a wide range of services, such as water purification, using a reverse osmosis water purification unit, fresh water distribution and power generation. The communications unit provided contact with headquarters in Honduras, and communicated with bases back in Canada. The operation was a great success, and well received by the Honduran people. This was the first deployment of DART, a team initially conceived after the Canadian Forces participated in relief efforts in Rwanda in 1994 and 1995

  15. Dynamic of population-dynamics in a medically important snail species Lymnaea (Radix Luteola (Lamarck

    Directory of Open Access Journals (Sweden)

    T. K. Misra

    1993-09-01

    Full Text Available The life-cycle parameters of the snail Lymnaea (Radix luteola and the factors influencing the same have been studied under laboratory conditions. Ins each month, from July 1990 to June 1991, a batch of 100 zero-day old individual were considered for studies. The snails of April batch survived for 19.42 days while those in December batch survived for 87.45 days. The May batch individual though survived for 65.67 days gained maximum shell size (15.84 mm in length and body weight (419.87 mg. All individuals of April batch died prior to attainment of sexual maturity. In the remaining 11 batches the snails became sexually mature between 32 and 53 days. At this stage, they were with varying shell lengths, 9.3 mm to 13,11 mm in respect to batches. The reproduction period varied from 1-67 days. An individual laid, on an average, 0,25 (March batch to 443.67 (May batch eggs in its life-span. A batch of such snails would leave 24312, 22520, 720268, 80408, 76067, 418165, 214, 9202, 0, 0, 2459386 and 127894 individuals at the end of 352nd day. Since the environmental conditions were almost similar the 'dynamic' of population dynamics seems to be involved with the 'strain' of the snail individuals of the batches concerned.

  16. Dynamics of a physiologically structured population in a time-varying environment

    DEFF Research Database (Denmark)

    Heilmann, Irene Louise Torpe; Starke, Jens; Andersen, Ken Haste

    2016-01-01

    Physiologically structured population models have become a valuable tool to model the dynamics of populations. In a stationary environment such models can exhibit equilibrium solutions as well as periodic solutions. However, for many organisms the environment is not stationary, but varies more...... or less regularly. In order to understand the interaction between an external environmental forcing and the internal dynamics in a population, we examine the response of a physiologically structured population model to a periodic variation in the food resource. We explore the addition of forcing in two...... cases: (A) where the population dynamics is in equilibrium in a stationary environment, and (B) where the population dynamics exhibits a periodic solution in a stationary environment. When forcing is applied in case A, the solutions are mainly periodic. In case B the forcing signal interacts...

  17. An Empirical Study of AI Population Dynamics with Million-agent Reinforcement Learning

    OpenAIRE

    Yang, Yaodong; Yu, Lantao; Bai, Yiwei; Wang, Jun; Zhang, Weinan; Wen, Ying; Yu, Yong

    2017-01-01

    In this paper, we conduct an empirical study on discovering the ordered collective dynamics obtained by a population of artificial intelligence (AI) agents. Our intention is to put AI agents into a simulated natural context, and then to understand their induced dynamics at the population level. In particular, we aim to verify if the principles developed in the real world could also be used in understanding an artificially-created intelligent population. To achieve this, we simulate a large-sc...

  18. A new ODE tumor growth modeling based on tumor population dynamics

    International Nuclear Information System (INIS)

    Oroji, Amin; Omar, Mohd bin; Yarahmadian, Shantia

    2015-01-01

    In this paper a new mathematical model for the population of tumor growth treated by radiation is proposed. The cells dynamics population in each state and the dynamics of whole tumor population are studied. Furthermore, a new definition of tumor lifespan is presented. Finally, the effects of two main parameters, treatment parameter (q), and repair mechanism parameter (r) on tumor lifespan are probed, and it is showed that the change in treatment parameter (q) highly affects the tumor lifespan

  19. A new ODE tumor growth modeling based on tumor population dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Oroji, Amin; Omar, Mohd bin [Institute of Mathematical Sciences, Faculty of Science University of Malaya, 50603 Kuala Lumpur, Malaysia amin.oroji@siswa.um.edu.my, mohd@um.edu.my (Malaysia); Yarahmadian, Shantia [Mathematics Department Mississippi State University, USA Syarahmadian@math.msstate.edu (United States)

    2015-10-22

    In this paper a new mathematical model for the population of tumor growth treated by radiation is proposed. The cells dynamics population in each state and the dynamics of whole tumor population are studied. Furthermore, a new definition of tumor lifespan is presented. Finally, the effects of two main parameters, treatment parameter (q), and repair mechanism parameter (r) on tumor lifespan are probed, and it is showed that the change in treatment parameter (q) highly affects the tumor lifespan.

  20. Intraspecific Competition and Population Dynamics of Aedes aegypti

    Science.gov (United States)

    Paixão, C. A.; Charret, I. C.; Lima, R. R.

    2012-04-01

    We report computational simulations for the evolution of the population of the dengue vector, Aedes aegypti mosquitoes. The results suggest that controlling the mosquito population, on the basis of intraspecific competition at the larval stage, can be an efficient mechanism for controlling the spread of the epidemic. The results also show the presence of a kind of genetic evolution in vector population, which results mainly in increasing the average lifespan of individuals in adulthood.

  1. Reducing violence in poor urban areas of Honduras by building community resilience through community-based interventions.

    Science.gov (United States)

    Hansen-Nord, Nete Sloth; Kjaerulf, Finn; Almendarez, Juan; Rodas, Victor Morales; Castro, Julio

    2016-11-01

    To examine the impact of a 3 year community-based violence prevention intervention on risk of violence and social capital in two poor urban communities in Honduras in 2011-2014. A quasi-experimental design pre and post implementation of the intervention was conducted based on data from two randomly selected samples using the same structured questionnaire in 2011 and in 2014. Community members had a 42 % lower risk of violence in 2014 compared to 2011. There was a positive relation between participation in the intervention and structural social capital, and participants had more than twice the likelihood of engaging in citizenship activities compared to the general population. The intervention contributed to decreasing violence and increasing community resilience in two urban areas in Honduras. Citizenship activities and active community participation in the violence prevention agenda rather than social trust and cohesion characteristics was affected by the intervention. This research introduces important lessons learned to future researchers aiming to retrieve very sensitive data in a similarly violent setting, and provides strong research opportunities within areas, which to this date remain undiscovered.

  2. Comparison of SureSight autorefractor and plusoptiX A09 photoscreener for vision screening in rural Honduras.

    Science.gov (United States)

    Silbert, David I; Matta, Noelle S; Ely, Amanda L

    2014-02-01

    To evaluate the SureSight autorefractor and compare it to the plusoptiX A09 photoscreener in the detection of amblyopia risk factors in a cohort of Honduran children examined during medical mission work and to assess the utility of both devices in the rural setting. The medical records of patients who had undergone SureSight autorefractor screening, plusoptiX photoscreening, and a gold standard pediatric ophthalmology examination, including cycloplegic refraction, during a recent medical mission trip to Honduras were retrospectively reviewed. A total of 216 children were examined. Of these, 9 (4%) were found to have amblyopia risk factors based on the current referral criteria of the American Association for Pediatric Ophthalmology and Strabismus on ophthalmological examination. The plusoptiX was found to have 89% sensitivity and 80% specificity; the SureSight, using manufacturer's referral criteria, was found to have sensitivity of 89% and specificity of 71%. Both devices were found to be reliable vision screening devices when used on the general population of remote villages in Honduras, although the specificity of the plusoptiX A09 was higher. Copyright © 2014 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.

  3. Data Driven Approach for High Resolution Population Distribution and Dynamics Models

    Energy Technology Data Exchange (ETDEWEB)

    Bhaduri, Budhendra L [ORNL; Bright, Eddie A [ORNL; Rose, Amy N [ORNL; Liu, Cheng [ORNL; Urban, Marie L [ORNL; Stewart, Robert N [ORNL

    2014-01-01

    High resolution population distribution data are vital for successfully addressing critical issues ranging from energy and socio-environmental research to public health to human security. Commonly available population data from Census is constrained both in space and time and does not capture population dynamics as functions of space and time. This imposes a significant limitation on the fidelity of event-based simulation models with sensitive space-time resolution. This paper describes ongoing development of high-resolution population distribution and dynamics models, at Oak Ridge National Laboratory, through spatial data integration and modeling with behavioral or activity-based mobility datasets for representing temporal dynamics of population. The model is resolved at 1 km resolution globally and describes the U.S. population for nighttime and daytime at 90m. Integration of such population data provides the opportunity to develop simulations and applications in critical infrastructure management from local to global scales.

  4. High population variability and source-sink dynamics in a solitary bee species.

    Science.gov (United States)

    Franzén, Markus; Nilsson, Sven G

    2013-06-01

    Although solitary bees are considered to play key roles in ecosystem functions, surprisingly few studies have explored their population dynamics. We investigated the population dynamics of a rare, declining, solitary bee (Andrena humilis) in a landscape of 80 km2 in southern Sweden from 2003 to 2011. Only one population was persistent throughout all years studied; most likely this population supplied the surrounding landscape with 11 smaller, temporary local populations. Despite stable pollen availability, the size of the persistent population fluctuated dramatically in a two-year cycle over the nine years, with 490-1230 nests in odd-numbered years and 21-48 nests in even-numbered years. These fluctuations were not significantly related to climatic variables or pollen availability. Nineteen colonization and 14 extinction events were recorded. Occupancy decreased with distance from the persistent population and increased with increasing resource (pollen) availability. There were significant positive correlations between the size of the persistent population and patch occupancy and colonization. Colonizations were generally more common in patches closer to the persistent population, whereas extinctions were independent of distance from the persistent population. Our results highlight the complex population dynamics that exist for this solitary bee species, which could be due to source-sink dynamics, a prolonged diapause, or can represent a bet-hedging strategy to avoid natural enemies and survive in small habitat patches. If large fluctuations in solitary bee populations prove to be widespread, it will have important implications for interpreting ecological relationships, bee conservation, and pollination.

  5. Dynamic energy budgets in population ecotoxicology: applications and outlook.

    NARCIS (Netherlands)

    Jager, T.; Barsi, A.; Hamda, N.T.; Martin, B.; Zimmer, E.I.; Ducrot, V.

    2014-01-01

    Most of the experimental testing in ecotoxicology takes place at the individual level, but the protection goals for environmental risk assessment are at the population level (or higher). Population modelling can fill this gap, but only models on a mechanistic basis allow for extrapolation beyond the

  6. Demographic processes in a local population: seasonal dynamics of ...

    African Journals Online (AJOL)

    ... differences in daily recruitment and within-patch survival rates. Males were most abundant relative to females early in the season, indicating protandry. Total adult population size was small and showed dramatic variation between the two years, indicating how vulnerable the local population is to demographic extinction.

  7. Dynamics of buckbrush populations under simulated forest restoration alternatives

    Science.gov (United States)

    David W. Huffman; Margaret M. Moore

    2008-01-01

    Plant population models are valuable tools for assessing ecological tradeoffs between forest management approaches. In addition, these models can provide insight on plant life history patterns and processes important for persistence and recovery of populations in changing environments. In this study, we evaluated a set of ecological restoration alternatives for their...

  8. Population Dynamics and Natural Resources in the Volta in the ...

    African Journals Online (AJOL)

    Also, population growth is causing shortfalls in agricultural land, deforestation and high demand on water resources in some of the sub-basins of the Volta River Keywords: Population, Natural resources, Volta River Basin, Human Settlement Land Use/Coverage Change Ghana Journal of Development Studies Vol.

  9. Termite Population Dynamics in Arenic Kandiudults as Influenced by ...

    African Journals Online (AJOL)

    Result shows that carbofuran significantly (P=<0.0001) recorded least termite population per square meter after tuber harvest, whereas A. indica leaves and municipal waste increased termite population per square meter. Also, cassava tuber yield was significantly influenced with application of A. indica leaves and ...

  10. Drug consumption by medical students in tegucigalpa, Honduras Uso de drogas entre estudiantes de medicina, tegucigalpa, Honduras O uso de drogas entre estudantes de medicina em tegucigalpa, Honduras

    Directory of Open Access Journals (Sweden)

    Juana Carolina Buchanan

    2008-08-01

    Full Text Available The use of drugs, in Honduras, involves 25% of college students. The most used substances include legal and recreational drugs, such as alcohol. This study aimed to identify the use of drugs and socio-demographic factors in a sample of 260 medical students. RESULTS: Average age of 20 years old, unemployed and religious women, single, with no children. Alcohol was the most consumed drug in the last six months for recreational purposes. The following stimulants were frequently consumed: caffeine, mate herb tea, energetic drinks and Coke. Drugs like marijuana, cocaine, valium and sedatives were used in smaller proportions. The reasons reported by women were: to alleviate tiredness and improve their academic performance. The men's reasons were recreation and to alleviate psychological tension. This research has implications for the development of drugs prevention programs in universities.En Honduras, el uso de drogas está presente en el 25% de estudiantes universitarios. Entre las drogas de mayor consumo están las lícitas y de uso recreacional, las bebidas alcohólicas siendo las lícitas y de uso recreacional, como el caso das bebidas alcohólicas. Ese estudio tuvo como propósito identificar el consumo de drogas y los factores sociodemográficos en una muestra de 260 estudiantes de medicina. RESULTADOS: edad media 20 años, mujeres, solteros, no tiene hijos, no trabajan, profesan religión. La droga más utilizada en los últimos seis meses es el alcohol, con consumo recreacional. Los estimulantes de consumo frecuente: la cafeína, el mate; las bebidas energizantes, la coca-cola; y las drogas ilicitas como la marihuana, la cocaína, el valium y los inductores del sueño en menores proporciones. Las razones de uso para mujeres fueron: aliviar el cansancio, mejorar el rendimiento académico; y para varones: divertirse y aliviar tensiones psicológicas. Esta investigación tiene implicaciones en el desarrollo de programas preventivos del uso de

  11. Chaos and order in stateless societies: Intercommunity exchange as a factor impacting the population dynamical patterns

    Energy Technology Data Exchange (ETDEWEB)

    Medvinsky, Alexander B., E-mail: medvinsky@iteb.ru [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino 142290, Moscow Region (Russian Federation); Rusakov, Alexey V. [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino 142290, Moscow Region (Russian Federation)

    2011-06-15

    Highlights: > We model community dynamics in stateless societies. > Intercommunity barter is shown to be a factor impacting the societies dynamics. > Increase in the human population growth rate can lead to appearance of chaos. > Secular and millennial cycles are found to arise as a result of the barter. - Abstract: The once abstract notions of dynamical chaos now appear naturally in various systems [Kaplan D, Glass L. Understanding nonlinear dynamics. New York: Springer; 1995]. As a result, future trajectories of the systems may be difficult to predict. In this paper, we demonstrate the appearance of chaotic dynamics in model human communities, which consist of producers of agricultural product and producers of agricultural equipment. In the case of a solitary community, the horizon of predictability of the human population dynamics is shown to be dependent on both intrinsic instability of the dynamics and the chaotic attractor sizes. Since a separate community is usually a part of a larger commonality, we study the dynamics of social systems consisting of two interacting communities. We show that intercommunity barter can lead to stabilization of the dynamics in one of the communities, which implies persistence of stable equilibrium under changes of the maximum value of the human population growth rate. However, in the neighboring community, the equilibrium turns into a stable limit cycle as the maximum value of the human population growth rate increases. Following an increase in the maximum value of the human population growth rate leads to period-doubling bifurcations resulting in chaotic dynamics. The horizon of predictability of the chaotic oscillations is found to be limited by 5 years. We demonstrate that the intercommunity interaction can lead to the appearance of long-period harmonics in the chaotic time series. The period of the harmonics is of order 100 and 1000 years. Hence the long-period changes in the population size may be considered as an

  12. Chaos and order in stateless societies: Intercommunity exchange as a factor impacting the population dynamical patterns

    International Nuclear Information System (INIS)

    Medvinsky, Alexander B.; Rusakov, Alexey V.

    2011-01-01

    Highlights: → We model community dynamics in stateless societies. → Intercommunity barter is shown to be a factor impacting the societies dynamics. → Increase in the human population growth rate can lead to appearance of chaos. → Secular and millennial cycles are found to arise as a result of the barter. - Abstract: The once abstract notions of dynamical chaos now appear naturally in various systems [Kaplan D, Glass L. Understanding nonlinear dynamics. New York: Springer; 1995]. As a result, future trajectories of the systems may be difficult to predict. In this paper, we demonstrate the appearance of chaotic dynamics in model human communities, which consist of producers of agricultural product and producers of agricultural equipment. In the case of a solitary community, the horizon of predictability of the human population dynamics is shown to be dependent on both intrinsic instability of the dynamics and the chaotic attractor sizes. Since a separate community is usually a part of a larger commonality, we study the dynamics of social systems consisting of two interacting communities. We show that intercommunity barter can lead to stabilization of the dynamics in one of the communities, which implies persistence of stable equilibrium under changes of the maximum value of the human population growth rate. However, in the neighboring community, the equilibrium turns into a stable limit cycle as the maximum value of the human population growth rate increases. Following an increase in the maximum value of the human population growth rate leads to period-doubling bifurcations resulting in chaotic dynamics. The horizon of predictability of the chaotic oscillations is found to be limited by 5 years. We demonstrate that the intercommunity interaction can lead to the appearance of long-period harmonics in the chaotic time series. The period of the harmonics is of order 100 and 1000 years. Hence the long-period changes in the population size may be considered as an

  13. First record of the invasive Asian fish tapeworm Bothriocephalus acheilognathi in Honduras, Central America.

    Science.gov (United States)

    Salgado-Maldonado, Guillermo; Matamoros, Wilfredo A; Kreiser, Brian R; Caspeta-Mandujano, Juan Manuel; Mendoza-Franco, Edgar F

    2015-01-01

    This paper provides the first report of the invasive Asian fish tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934, in Honduras. The cestode was found in Profundulus portillorum (Cyprinodontiformes: Profundulidae), which represents a new host record, and which is a member of a genus faced with a variety of conservation challenges, now potentially complicated by the presence of this pathogenic cestode. Nearly complete sequence data from the ITS-1 5.8S and ITS-2 regions corroborate the determination based on morphological characteristics. Several species of carp were introduced to Honduras for aquaculture purposes in the early 1980s and the presence of the Asian fish tapeworm in Honduras may be related to these introductions. In addition, this report documents the currently known geographical distribution of this parasite in Central America, first recorded from Panamá and now from Honduras. © G. Salgado-Maldonado et al., published by EDP Sciences, 2015.

  14. Clinical Features and Neurologic Complications of Children Hospitalized With Chikungunya Virus in Honduras.

    Science.gov (United States)

    Samra, José A; Hagood, Nancy L; Summer, Andrea; Medina, Marco T; Holden, Kenton R

    2017-07-01

    The first case of Chikungunya virus in Honduras was identified in 2014. The virus has spread widely across Honduras via the Aedes aegypti mosquito, leading to an outbreak of Chikungunya virus (CHIKV) in 2015 that significantly impacted children. A retrospective chart review of 235 children diagnosed with CHIKV and admitted to the National Autonomous University of Honduras Hospital Escuela (Hospital Escuela) in Tegucigalpa, Honduras, was accomplished with patients who were assessed for clinical features and neurologic complications. Of 235 children admitted to Hospital Escuela with CHIKV, the majority had symptoms of fever, generalized erythematous rash, and irritability. Fourteen percent had clinical arthritis. Ten percent of patients had seizures. Six percent had meningoencephalitis. There were 2 childhood deaths during the course of this study, one from meningoencephalitis and another from myocarditis. Chikungunya virus can cause severe complications in children, the majority of which impact the central nervous system.

  15. A mechanistic analysis of density dependence in algal population dynamics

    Directory of Open Access Journals (Sweden)

    Adrian eBorlestean

    2015-04-01

    Full Text Available Population density regulation is a fundamental principle in ecology, but the specific process underlying functional expression of density dependence remains to be fully elucidated. One view contends that patterns of density dependence are largely fixed across a species irrespective of environmental conditions, whereas another is that the strength and expression of density dependence are fundamentally variable depending on the nature of exogenous or endogenous constraints acting on the population. We conducted a study investigating the expression of density dependence in Chlamydomonas spp. grown under a gradient from low to high nutrient density. We predicted that the relationship between per capita growth rate (pgr and population density would vary from concave up to concave down as nutrient density became less limiting and populations experienced weaker density regulation. Contrary to prediction, we found that the relationship between pgr and density became increasingly concave-up as nutrient levels increased. We also found that variation in pgr increased, and pgr levels reached higher maxima in nutrient-limited environments. Most likely, these results are attributable to population growth suppression in environments with high intraspecific competition due to limited nutrient resources. Our results suggest that density regulation is strongly variable depending on exogenous and endogenous processes acting on the population, implying that expression of density dependence depends extensively on local conditions. Additional experimental work should reveal the mechanisms influencing how the expression of density dependence varies across populations through space and time.

  16. Use of Mobile Device Data To Better Estimate Dynamic Population Size for Wastewater-Based Epidemiology.

    Science.gov (United States)

    Thomas, Kevin V; Amador, Arturo; Baz-Lomba, Jose Antonio; Reid, Malcolm

    2017-10-03

    Wastewater-based epidemiology is an established approach for quantifying community drug use and has recently been applied to estimate population exposure to contaminants such as pesticides and phthalate plasticizers. A major source of uncertainty in the population weighted biomarker loads generated is related to estimating the number of people present in a sewer catchment at the time of sample collection. Here, the population quantified from mobile device-based population activity patterns was used to provide dynamic population normalized loads of illicit drugs and pharmaceuticals during a known period of high net fluctuation in the catchment population. Mobile device-based population activity patterns have for the first time quantified the high degree of intraday, week, and month variability within a specific sewer catchment. Dynamic population normalization showed that per capita pharmaceutical use remained unchanged during the period when static normalization would have indicated an average reduction of up to 31%. Per capita illicit drug use increased significantly during the monitoring period, an observation that was only possible to measure using dynamic population normalization. The study quantitatively confirms previous assessments that population estimates can account for uncertainties of up to 55% in static normalized data. Mobile device-based population activity patterns allow for dynamic normalization that yields much improved temporal and spatial trend analysis.

  17. Mareros and pandilleros in Honduras: the reintegration of youth gang members

    OpenAIRE

    Van Damme, Ellen

    2016-01-01

    The focus of this research is on the reintegration of youth gang members in Honduras. The aim of this qualitative study is to broaden the knowledge of reintegration processes and programs in one specific country in Central America, namely, Honduras. A sample of fourteen interviews with stakeholders in the field of maras and pandillas has been investigated and the results revealed some similarities between the different methods of reintegration. Our data suggest that a comprehensive process, i...

  18. Extinction dynamics of a discrete population in an oasis.

    Science.gov (United States)

    Berti, Stefano; Cencini, Massimo; Vergni, Davide; Vulpiani, Angelo

    2015-07-01

    Understanding the conditions ensuring the persistence of a population is an issue of primary importance in population biology. The first theoretical approach to the problem dates back to the 1950s with the Kierstead, Slobodkin, and Skellam (KiSS) model, namely a continuous reaction-diffusion equation for a population growing on a patch of finite size L surrounded by a deadly environment with infinite mortality, i.e., an oasis in a desert. The main outcome of the model is that only patches above a critical size allow for population persistence. Here we introduce an individual-based analog of the KiSS model to investigate the effects of discreteness and demographic stochasticity. In particular, we study the average time to extinction both above and below the critical patch size of the continuous model and investigate the quasistationary distribution of the number of individuals for patch sizes above the critical threshold.

  19. POPULATION DYNAMICS OF SMALL MAMMALS ACROSS A NITROGEN AMENDED LANDSCAPE

    Science.gov (United States)

    Biogeochemical alterations of the nitrogen cycle from anthropogenic activities could have significant effects on ecological processes at the population, community and ecosystem levels. Nitrogen additions in grasslands have produced qualitative and quantitative changes in vegetat...

  20. Do we need demographic data to forecast plant population dynamics?

    Science.gov (United States)

    Tredennick, Andrew T.; Hooten, Mevin B.; Adler, Peter B.

    2017-01-01

    Rapid environmental change has generated growing interest in forecasts of future population trajectories. Traditional population models built with detailed demographic observations from one study site can address the impacts of environmental change at particular locations, but are difficult to scale up to the landscape and regional scales relevant to management decisions. An alternative is to build models using population-level data that are much easier to collect over broad spatial scales than individual-level data. However, it is unknown whether models built using population-level data adequately capture the effects of density-dependence and environmental forcing that are necessary to generate skillful forecasts.Here, we test the consequences of aggregating individual responses when forecasting the population states (percent cover) and trajectories of four perennial grass species in a semi-arid grassland in Montana, USA. We parameterized two population models for each species, one based on individual-level data (survival, growth and recruitment) and one on population-level data (percent cover), and compared their forecasting accuracy and forecast horizons with and without the inclusion of climate covariates. For both models, we used Bayesian ridge regression to weight the influence of climate covariates for optimal prediction.In the absence of climate effects, we found no significant difference between the forecast accuracy of models based on individual-level data and models based on population-level data. Climate effects were weak, but increased forecast accuracy for two species. Increases in accuracy with climate covariates were similar between model types.In our case study, percent cover models generated forecasts as accurate as those from a demographic model. For the goal of forecasting, models based on aggregated individual-level data may offer a practical alternative to data-intensive demographic models. Long time series of percent cover data already exist

  1. The impact of rapid evolution on population dynamics in the wild: experimental test of eco-evolutionary dynamics.

    Science.gov (United States)

    Turcotte, Martin M; Reznick, David N; Hare, J Daniel

    2011-11-01

    Rapid evolution challenges the assumption that evolution is too slow to impact short-term ecological dynamics. This insight motivates the study of 'Eco-Evolutionary Dynamics' or how evolution and ecological processes reciprocally interact on short time scales. We tested how rapid evolution impacts concurrent population dynamics using an aphid (Myzus persicae) and an undomesticated host (Hirschfeldia incana) in replicated wild populations. We manipulated evolvability by creating non-evolving (single clone) and potentially evolving (two-clone) aphid populations that contained genetic variation in intrinsic growth rate. We observed significant evolution in two-clone populations whether or not they were exposed to predators and competitors. Evolving populations grew up to 42% faster and attained up to 67% higher density, compared with non-evolving control populations but only in treatments exposed to competitors and predators. Increased density also correlates with relative fitness of competing clones suggesting a full eco-evolutionary dynamic cycle defined as reciprocal interactions between evolution and density. © 2011 Blackwell Publishing Ltd/CNRS.

  2. Chaotic population dynamics and biology of the top-predator

    International Nuclear Information System (INIS)

    Rai, Vikas; Upadhyay, Ranjit Kumar

    2004-01-01

    We study how the dynamics of a food chain depends on the biology of the top-predator. We consider two model food chains with specialist and generalist top-predators. Both types of food chains display same type of chaotic behavior, short-term recurrent chaos; but the generating mechanisms are drastically different. Food chains with specialist top-predators are dictated by exogenous stochastic factors. On the contrary, the dynamics of those with the generalist top-predator is governed by deterministic changes in system parameters. The study also suggests that robust chaos would be a rarity

  3. Causes and consequences of complex population dynamics in an annual plant, Cardamine pensylvanica

    Energy Technology Data Exchange (ETDEWEB)

    Crone, E.E.

    1995-11-08

    The relative importance of density-dependent and density-independent factors in determining the population dynamics of plants has been widely debated with little resolution. In this thesis, the author explores the effects of density-dependent population regulation on population dynamics in Cardamine pensylvanica, an annual plant. In the first chapter, she shows that experimental populations of C. pensylvanica cycled from high to low density in controlled constant-environment conditions. These cycles could not be explained by external environmental changes or simple models of direct density dependence (N{sub t+1} = f[N{sub t}]), but they could be explained by delayed density dependence (N{sub t+1} = f[N{sub t}, N{sub t+1}]). In the second chapter, she shows that the difference in the stability properties of population growth models with and without delayed density dependence is due to the presence of Hopf as well as slip bifurcations from stable to chaotic population dynamics. She also measures delayed density dependence due to effects of parental density on offspring quality in C. pensylvanica and shows that this is large enough to be the cause of the population dynamics observed in C. pensylvanica. In the third chapter, the author extends her analyses of density-dependent population growth models to include interactions between competing species. In the final chapter, she compares the effects of fixed spatial environmental variation and variation in population size on the evolutionary response of C. pensylvanica populations.

  4. Population dynamics of Aphis gossypii Glover and in sole and intercropping systems of cotton and cowpea.

    Science.gov (United States)

    Fernandes, Francisco S; Godoy, Wesley A C; Ramalho, Francisco S; Garcia, Adriano G; Santos, Bárbara D B; Malaquias, José B

    2018-01-01

    Population dynamics of aphids have been studied in sole and intercropping systems. These studies have required the use of more precise analytical tools in order to better understand patterns in quantitative data. Mathematical models are among the most important tools to explain the dynamics of insect populations. This study investigated the population dynamics of aphids Aphis gossypii and Aphis craccivora over time, using mathematical models composed of a set of differential equations as a helpful analytical tool to understand the population dynamics of aphids in arrangements of cotton and cowpea. The treatments were sole cotton, sole cowpea, and three arrangements of cotton intercropped with cowpea (t1, t2 and t3). The plants were infested with two aphid species and were evaluated at 7, 14, 28, 35, 42, and 49 days after the infestations. Mathematical models were used to fit the population dynamics of two aphid species. There were good fits for aphid dynamics by mathematical model over time. The highest population peak of both species A. gossypii and A. craccivora was found in the sole crops, and the lowest population peak was found in crop system t2. These results are important for integrated management programs of aphids in cotton and cowpea.

  5. The demographic drivers of local population dynamics in two rare migratory birds.

    Science.gov (United States)

    Schaub, Michael; Reichlin, Thomas S; Abadi, Fitsum; Kéry, Marc; Jenni, Lukas; Arlettaz, Raphaël

    2012-01-01

    The exchange of individuals among populations can have strong effects on the dynamics and persistence of a given population. Yet, estimation of immigration rates remains one of the greatest challenges for animal demographers. Little empirical knowledge exists about the effects of immigration on population dynamics. New integrated population models fitted using Bayesian methods enable simultaneous estimation of fecundity, survival and immigration, as well as the growth rate of a population of interest. We applied this novel analytical framework to the demography of two populations of long-distance migratory birds, hoopoe Upupa epops and wryneck Jynx torquilla, in a study area in south-western Switzerland. During 2002-2010, the hoopoe population increased annually by 11%, while the wryneck population remained fairly stable. Apparent juvenile and adult survival probability was nearly identical in both species, but fecundity and immigration were slightly higher in the hoopoe. Hoopoe population growth rate was strongly correlated with juvenile survival, fecundity and immigration, while that of wrynecks strongly correlated only with immigration. This indicates that demographic components impacting the arrival of new individuals into the populations were more important for their dynamics than demographic components affecting the loss of individuals. The finding that immigration plays a crucial role in the population growth rates of these two rare species emphasizes the need for a broad rather than local perspective for population studies, and the development of wide-scale conservation actions.

  6. The 2013 Elections in Honduras: End of Bipartisanship?

    Directory of Open Access Journals (Sweden)

    Carlos Barrachina

    2014-06-01

    Full Text Available In late 2013 Honduras experienced one of the most important elections in its history. After withdrawal of the presence of Manuel Zelaya in 2009, and the government of Porfirio "Pepe" Lobo (2010-2014, the traditional Honduran bipartisanship and the strong emergence of the "left" in the political scene was first questioned. Besides the Partido Nacional and the Partido Liberal, the Partido Libertad y Refundación and the Partido Anticorrupción have achieved significant results. The party structures of the Partido Nacional and the Partido Liberal, however, have maintained as a key political forces in the Honduran political system, having preserved the political leadership of the country's major cities.

  7. Consequences of population models on the dynamics of food chains.

    NARCIS (Netherlands)

    Kooi, B.W.; Boer, M.P.; Kooijman, S.A.L.M.

    1998-01-01

    A class of bioenergetic ecological models is studied for the dynamics of food chains with a nutrient at the base. A constant influx rate of the nutrient and a constant efflux rate for all trophic levels is assumed. Starting point is a simple model where prey is converted into predator with a fixed

  8. Mapping Populations: An Objective Measurement of Revolutionary Dynamics

    Science.gov (United States)

    2013-06-01

    the figurehead for the NSDAP because of his apparent ubiquity with the working class and the machinations of the bourgeoisie society members...dynamics between the proletariat and the bourgeoisie of German society in the 1920’s exemplified the need for a figurehead. Furthermore, the

  9. Structural and geophysical interpretation of Roatan Island, Honduras, Western Caribbean

    Science.gov (United States)

    Sutton, Daniel Scott

    Roatan Island is the largest of the Bay Islands of Honduras. These islands form an emergent crest off the Caribbean coast of Honduras called the Bonacca Ridge. The Bartlett Trough to the north and subsequent Bonacca Ridge were likely formed due to the transform fault system of the Motagua-Swan Islands Fault System. This fault system forms the tectonic plate boundary between the North American and Caribbean plates. Although the timing and kinematics are poorly constrained, the Bay Islands and the Bonacca Ridge were likely uplifted due to transpression along this left-lateral strike-slip system. With limited regional exposures along the adjacent tectonic boundary, this study aimed to present a structural interpretation for Roatan. This new interpretation is further explained through regional considerations for a suggested geologic history of the northwestern Caribbean. In order to better constrain the kinematics of uplift and exhumation of Roatan Island, structural, gravity, and magnetic surveys were conducted. Principal attention was directed to the structural relationship between the geologic units and their relationship to one another through deformation. Resulting geologic cross-sections from this study present the metamorphic basement exposed throughout the island to be in a normal structural order consisting of biotite schist and gneiss, with overlying units of chlorite schist, carbonate, and conglomerate. These units have relatively concordant strike and dip measurements, consistent with resultant magnetic survey readings. Additionally, large and irregular bodies of amphibolite and serpentinite throughout the island are interpreted to have been emplaced as mafic and ultra-mafic intrusions in weakness zones along Early Paleogene transform system fault planes. The interpretation and suggested geologic history from this study demonstrate the importance of transpressive tectonics both local to Roatan and regionally throughout geologic history. Consideration of

  10. The finite state projection approach to analyze dynamics of heterogeneous populations

    Science.gov (United States)

    Johnson, Rob; Munsky, Brian

    2017-06-01

    Population modeling aims to capture and predict the dynamics of cell populations in constant or fluctuating environments. At the elementary level, population growth proceeds through sequential divisions of individual cells. Due to stochastic effects, populations of cells are inherently heterogeneous in phenotype, and some phenotypic variables have an effect on division or survival rates, as can be seen in partial drug resistance. Therefore, when modeling population dynamics where the control of growth and division is phenotype dependent, the corresponding model must take account of the underlying cellular heterogeneity. The finite state projection (FSP) approach has often been used to analyze the statistics of independent cells. Here, we extend the FSP analysis to explore the coupling of cell dynamics and biomolecule dynamics within a population. This extension allows a general framework with which to model the state occupations of a heterogeneous, isogenic population of dividing and expiring cells. The method is demonstrated with a simple model of cell-cycle progression, which we use to explore possible dynamics of drug resistance phenotypes in dividing cells. We use this method to show how stochastic single-cell behaviors affect population level efficacy of drug treatments, and we illustrate how slight modifications to treatment regimens may have dramatic effects on drug efficacy.

  11. Analysis of Population Diversity of Dynamic Probabilistic Particle Swarm Optimization Algorithms

    Directory of Open Access Journals (Sweden)

    Qingjian Ni

    2014-01-01

    Full Text Available In evolutionary algorithm, population diversity is an important factor for solving performance. In this paper, combined with some population diversity analysis methods in other evolutionary algorithms, three indicators are introduced to be measures of population diversity in PSO algorithms, which are standard deviation of population fitness values, population entropy, and Manhattan norm of standard deviation in population positions. The three measures are used to analyze the population diversity in a relatively new PSO variant—Dynamic Probabilistic Particle Swarm Optimization (DPPSO. The results show that the three measure methods can fully reflect the evolution of population diversity in DPPSO algorithms from different angles, and we also discuss the impact of population diversity on the DPPSO variants. The relevant conclusions of the population diversity on DPPSO can be used to analyze, design, and improve the DPPSO algorithms, thus improving optimization performance, which could also be beneficial to understand the working mechanism of DPPSO theoretically.

  12. Universality in exact quantum state population dynamics and control

    International Nuclear Information System (INIS)

    Wu, Lian-Ao; Segal, Dvira; Brumer, Paul; Egusquiza, Inigo L.

    2010-01-01

    We consider an exact population transition, defined as the probability of finding a state at a final time that is exactly equal to the probability of another state at the initial time. We prove that, given a Hamiltonian, there always exists a complete set of orthogonal states that can be employed as time-zero states for which this exact population transition occurs. The result is general: It holds for arbitrary systems, arbitrary pairs of initial and final states, and for any time interval. The proposition is illustrated with several analytic models. In particular, we demonstrate that in some cases, by tuning the control parameters, a complete transition might occur, where a target state, vacant at t=0, is fully populated at time τ.

  13. The population dynamical implications of male-biased parasitism in different mating systems.

    Directory of Open Access Journals (Sweden)

    Martin R Miller

    2007-07-01

    Full Text Available Although there is growing evidence that males tend to suffer higher levels of parasitism than females, the implications of this for the population dynamics of the host population are not yet understood. Here we build on an established 'two-sex' model and investigate how increased susceptibility to infection in males affects the dynamics, under different mating systems. We investigate the effect of pathogenic disease at different case mortalities, under both monogamous and polygynous mating systems. If the case mortality is low, then male-biased parasitism appears similar to unbiased parasitism in terms of its effect on the population dynamics. At higher case mortalities, we identified significant differences between male-biased and unbiased parasitism. A host population may therefore be differentially affected by male-biased and unbiased parasitism. The dynamical outcome is likely to depend on a complex interaction between the host's mating system and demography, and the parasite virulence.

  14. Population, environment dynamics, poverty and quality of life in China.

    Science.gov (United States)

    Gu, B

    1996-12-01

    This article focuses on the growth in poverty, environmental concerns, and Chinese government efforts to eliminate poverty with integrated programs. China had 1.2 billion people in February 1995, or 20% of total world population on 7% of the world's arable land. The rate of natural increase was 1.1% in 1996. China's population could double to 2.4 billion by 2060. About 14 million people are added every year. China has about 300 million women of childbearing age. Even with 1 child per woman, population would grow by 300 million. 18 provinces have population growth over the national average of 1.49%. Many of these provinces are also provinces with high population density, high poverty ratios, and higher than 2 birth orders. The highest growth is in western China. Poor households have a lower quality of life, more disabled members, high rates of endemic disease, and illiteracy. Among the very poor without adequate food or clothing, environmental protection is a meaningless concept. Poverty alleviation strategies have shifted from relief to economic development. State support combined with local resources in a pooling approach pays for poverty alleviation programs. The central government's share will increase until the year 2000. The number of poor was 80 million in 1994 (9% of total population) living in 592 poor counties in remote and mountainous areas. The number of poor was reduced to 65 million in 1996. An integrated approach of family planning and poverty alleviation operates in Jinzhai County of Anhui province. China is determined to reorient to a "service-oriented, client- centered, woman-sensitive, and rural-emphasized approach."

  15. Dynamics of Cercospora zeina populations in maize-based agro ...

    African Journals Online (AJOL)

    La variation dans le temps au sein d'une population, est fonction de facteurs relatifs à l'écologie, la biologie et l'histoire de vie des pathogènes. Elle varie d'un être vivant à un autre et d'un écosystème à un autre. L'objectif de cette étude était d'évaluer la variabilité génétique au sein des populations de Cercospora zeina ...

  16. The dynamics of discrete populations and series of events

    CERN Document Server

    Hopcraft, Keith Iain; Ridley, Kevin D

    2014-01-01

    IntroductionReferencesStatistical PreliminariesIntroductionProbability DistributionsMoment-Generating FunctionsDiscrete ProcessesSeries of EventsSummaryFurther ReadingMarkovian Population ProcessesIntroductionBirths and DeathsImmigration and the Poisson ProcessThe Effect of MeasurementCorrelation of CountsSummaryFurther ReadingThe Birth-Death-Immigration ProcessIntroductionRate Equations for the ProcessEquation for the Generating FunctionGeneral Time-Dependent SolutionFluctuation Characteristics of a Birth-Death-Immigration PopulationSampling and Measurement ProcessesCorrelation of CountsSumma

  17. A new scorpion species of genus Diplocentrus Peters, 1861 (Scorpiones: Diplocentridae) endemic to Islas de la Bahia, Honduras.

    Science.gov (United States)

    Sagastume-Espinoza, Kevin O; Longhorn, Stuart J; Santibáñez-López, Carlos E

    2015-07-01

    Three species of genus Diplocentrus are found in north-northwestern Honduras. These species represent the southern east limits of Diplocentrus' distribution. In recent years, a broad survey of arachnids in Honduras has yielded a collection of several specimens of an undescribed species from two islands in northern Honduras. This new species represents the second species of the genus inhabiting an island. The present contribution describes this new species, and compares it against its most similar relatives. A dichotomous key for the identification of the species of Diplocentrus in Honduras is also included. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  18. Modelling population dynamics model formulation, fitting and assessment using state-space methods

    CERN Document Server

    Newman, K B; Morgan, B J T; King, R; Borchers, D L; Cole, D J; Besbeas, P; Gimenez, O; Thomas, L

    2014-01-01

    This book gives a unifying framework for estimating the abundance of open populations: populations subject to births, deaths and movement, given imperfect measurements or samples of the populations.  The focus is primarily on populations of vertebrates for which dynamics are typically modelled within the framework of an annual cycle, and for which stochastic variability in the demographic processes is usually modest. Discrete-time models are developed in which animals can be assigned to discrete states such as age class, gender, maturity,  population (within a metapopulation), or species (for multi-species models). The book goes well beyond estimation of abundance, allowing inference on underlying population processes such as birth or recruitment, survival and movement. This requires the formulation and fitting of population dynamics models.  The resulting fitted models yield both estimates of abundance and estimates of parameters characterizing the underlying processes.  

  19. Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus: a comparison between central and range edge populations.

    Directory of Open Access Journals (Sweden)

    Rita M Araújo

    Full Text Available Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity of population growth rate showed that fertility elements had a small contribution to λ(s that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental

  20. Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus): a comparison between central and range edge populations.

    Science.gov (United States)

    Araújo, Rita M; Serrão, Ester A; Sousa-Pinto, Isabel; Åberg, Per

    2014-01-01

    Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s)) of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s) much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity) of population growth rate showed that fertility elements had a small contribution to λ(s) that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental variability and

  1. Life history and population dynamics of an estuarine amphipod, Eriopisa chilkensis Chilton (Gammaridae)

    Digital Repository Service at National Institute of Oceanography (India)

    Aravind, N.P.; Sheeba, P.; Nair, K.K.C.; Achuthankutty, C.T.

    Life history and Population Dynamics of an Estuarine Amphipod –Eriopisa chilkensis Chilton (Gammaridae) Nisha. P. Aravind, P. Sheeba, K.K.C. Nair and C.T.Achuthankutty* National Institute of Oceanography, Regional Centre, Cochin 682018, India... of laboratory data to the field suggests that E. chilkensis in Cochin estuary has a multivoltine life cycle. Key words: - Eriopisa chilkensis, Amphipoda, life cycle, population dynamics, Cochin estuary, India 2 1. Introduction Life-history traits of 214 amphipod...

  2. Emergent Patterns of Diversity and Dynamics in Natural Populations of Planktonic Vibrio Bacteria

    Science.gov (United States)

    2005-06-01

    1973. Ecology of Vibrio parahemolyticus in mixed-template amplifications: formation, consequences and elimination by Chesapeake Bay. J. Bacteriol. 113...Science 1930 and Engineering DOCTORAL DISSERTATION Emergent Patterns of Diversity and Dynamics in Natural Populations of Planktonic Vibrio Bacteria by...DYNAMICS IN NATURAL POPULATIONS OF PLANKTONIC VIBRIO BACTERIA by Janelle Ren6e Thompson B.S. Biological Sciences, Stanford University 1998 M.S

  3. The significance of nonviable eggs for Daphnia population dynamics

    NARCIS (Netherlands)

    Boersma, M.; Vijverberg, J.

    1995-01-01

    Egg mortality was studied in populations of Daphnia galeata, Daphnia cucullata, and the hybrid between these species. In Tjeukemeer, a shallow eutrophic lake in the Netherlands, egg mortality in daphnids manifested itself as an apparent increase in the frequency of eggs in the early developmental

  4. Population dynamics of Lemniscomys rosalia (Muridae: Rodentia) in ...

    African Journals Online (AJOL)

    Numerous studies have reported increases in rodent populations following good rainfall (Nel 1978; Perrin & Swanepoel 1987; Bronner, Rau- ten bach & Meester 1988). This relationship is thought to be an indirect one where increased rainfall acts to increase cover and food supply. thus enabling rodents to reproduce (Neal.

  5. A stage-based model of manatee population dynamics

    Science.gov (United States)

    Runge, M.C.; Langtimm, C.A.; Kendall, W.L.

    2004-01-01

    A stage-structured population model for the Florida manatee (Trichechus manatus latirostris) was developed that explicitly incorporates uncertainty in parameter estimates. The growth rates calculated with this model reflect the status of the regional populations over the most recent 10-yr period. The Northwest and Upper St. Johns River regions have growth rates (8) of 1.037 (95% interval, 1.016?1.056) and 1.062 (1.037?1.081), respectively. The Southwest region has a growth rate of 0.989 (0.946?1.024), suggesting this population has been declining at about 1.1% per year. The estimated growth rate in the Atlantic region is 1.010 (0.988?1.029), but there is some uncertainty about whether adult survival rates have been constant over the last 10 yr; using the mean survival rates from the most recent 5-yr period, the estimated growth rate in this region is 0.970 (0.938?0.998). Elasticity analysis indicates that the most effective management actions should seek to increase adult survival rates. Decomposition of the uncertainty in the growth rates indicates that uncertainty about population status can best be reduced through increased monitoring of adult survival rate.

  6. The larval development and population dynamics of Derocheilocaris ...

    African Journals Online (AJOL)

    Seven larval stages of Derocheilocaris algoensis have been described and appear to be identical with those of D. typica from North America. This stresses the remarkable conservativeness of this subclass of Crustacea. The population biology of D. algoensis has been studied over 16 months and reproduction has been ...

  7. Connection between Dynamically Derived Initial Mass Function Normalization and Stellar Population Parameters

    NARCIS (Netherlands)

    McDermid, Richard M.; Cappellari, Michele; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS3D project. We study trends between our dynamically derived IMF normalization αdyn ≡

  8. Radiation belt seed population and its association with the relativistic electron dynamics: A statistical study: Radiation Belt Seed Population

    International Nuclear Information System (INIS)

    Tang, C. L.; Wang, Y. X.; Ni, B.; Zhang, J.-C.

    2017-01-01

    Using the Van Allen Probes data, we study the radiation belt seed population and it associated with the relativistic electron dynamics during 74 geomagnetic storm events. Based on the flux changes of 1 MeV electrons before and after the storm peak, these storm events are divided into two groups of “non-preconditioned” and “preconditioned”. The statistical study shows that the storm intensity is of significant importance for the distribution of the seed population (336 keV electrons) in the outer radiation belt. However, substorm intensity can also be important to the evolution of the seed population for some geomagnetic storm events. For non-preconditioned storm events, the correlation between the peak fluxes and their L-shell locations of the seed population and relativistic electrons (592 keV, 1.0 MeV, 1.8 MeV, and 2.1 MeV) is consistent with the energy-dependent dynamic processes in the outer radiation belt. For preconditioned storm events, the correlation between the features of the seed population and relativistic electrons is not fully consistent with the energy-dependent processes. It is suggested that the good correlation between the radiation belt seed population and ≤1.0 MeV electrons contributes to the prediction of the evolution of ≤1.0 MeV electrons in the Earth’s outer radiation belt during periods of geomagnetic storms.

  9. Dispersal, density dependence, and population dynamics of a fungal microbe on leaf surfaces.

    Science.gov (United States)

    Woody, Scott T; Ives, Anthony R; Nordheim, Erik V; Andrews, John H

    2007-06-01

    Despite the ubiquity and importance of microbes in nature, little is known about their natural population dynamics, especially for those that occupy terrestrial habitats. Here we investigate the dynamics of the yeast-like fungus Aureobasidium pullulans (Ap) on apple leaves in an orchard. We asked three questions. (1) Is variation in fungal population density among leaves caused by variation in leaf carrying capacities and strong density-dependent population growth that maintains densities near carrying capacity? (2) Do resident populations have competitive advantages over immigrant cells? (3) Do Ap dynamics differ at different times during the growing season? To address these questions, we performed two experiments at different times in the growing season. Both experiments used a 2 x 2 factorial design: treatment 1 removed fungal cells from leaves to reveal density-dependent population growth, and treatment 2 inoculated leaves with an Ap strain engineered to express green fluorescent protein (GFP), which made it possible to track the fate of immigrant cells. The experiments showed that natural populations of Ap vary greatly in density due to sustained differences in carrying capacities among leaves. The maintenance of populations close to carrying capacities indicates strong density-dependent processes. Furthermore, resident populations are strongly competitive against immigrants, while immigrants have little impact on residents. Finally, statistical models showed high population growth rates of resident cells in one experiment but not in the other, suggesting that Ap experiences relatively "good" and "bad" periods for population growth. This picture of Ap dynamics conforms to commonly held, but rarely demonstrated, expectations of microbe dynamics in nature. It also highlights the importance of local processes, as opposed to immigration, in determining the abundance and dynamics of microbes on surfaces in terrestrial systems.

  10. Dynamics in the devolopment of donkey population in Bulgaria

    Directory of Open Access Journals (Sweden)

    R. Vlaeva

    2017-03-01

    Full Text Available The aim of the recent study was to trace back the development of the donkey population in Bulgaria for the period 1950 – 2015. For that purpose the data from the National Statistic Institute and FAO was processed and other sources related to the problem were analyzed. Donkeys in Bulgaria used to be a comparatively large share of the traction power animals in the past, with the occurance of the social and economical changes after 1990 their number was dramatically reduced. This process is most noticeable after 2000, when for five year period until 2005 the donkey population in Bulgaria drops down from 207000 to 90000 individuals, as in 2013 this number falls down to 35000 according to FAO.

  11. The dynamics of endemic malaria in populations of varying size

    International Nuclear Information System (INIS)

    Ngwa, G.A.

    2001-10-01

    A mathematical model for endemic malaria involving variable human and mosquito populations is analysed. A threshold parameter R 0 exists and the disease can persist if and only if R 0 exceeds 1. R 0 is seen to be a generalisation of the basic reproduction ratio associated with the Ross-Macdonald model for malaria transmission. The disease free equilibrium always exist and is globally stable when R 0 is below 1. A perturbation analysis is used to approximate the endemic equilibrium in the important case where the disease related death rate is nonzero. A diffusion approximation is used to approximate the quasi-stationary distribution of the associated stochastic model. Numerical simulations show that when R 0 is distinctly greater than 1, the endemic deterministic equilibrium is globally stable. Furthermore, in quasi-stationarity, the stochastic process undergoes oscillations about a mean population whose size can be approximated by the stable endemic deterministic equilibrium. (author)

  12. Does probability of occurrence relate to population dynamics?

    Science.gov (United States)

    Thuiller, Wilfried; Münkemüller, Tamara; Schiffers, Katja H; Georges, Damien; Dullinger, Stefan; Eckhart, Vincent M; Edwards, Thomas C; Gravel, Dominique; Kunstler, Georges; Merow, Cory; Moore, Kara; Piedallu, Christian; Vissault, Steve; Zimmermann, Niklaus E; Zurell, Damaris; Schurr, Frank M

    2014-12-01

    Hutchinson defined species' realized niche as the set of environmental conditions in which populations can persist in the presence of competitors. In terms of demography, the realized niche corresponds to the environments where the intrinsic growth rate ( r ) of populations is positive. Observed species occurrences should reflect the realized niche when additional processes like dispersal and local extinction lags do not have overwhelming effects. Despite the foundational nature of these ideas, quantitative assessments of the relationship between range-wide demographic performance and occurrence probability have not been made. This assessment is needed both to improve our conceptual understanding of species' niches and ranges and to develop reliable mechanistic models of species geographic distributions that incorporate demography and species interactions. The objective of this study is to analyse how demographic parameters (intrinsic growth rate r and carrying capacity K ) and population density ( N ) relate to occurrence probability ( P occ ). We hypothesized that these relationships vary with species' competitive ability. Demographic parameters, density, and occurrence probability were estimated for 108 tree species from four temperate forest inventory surveys (Québec, Western US, France and Switzerland). We used published information of shade tolerance as indicators of light competition strategy, assuming that high tolerance denotes high competitive capacity in stable forest environments. Interestingly, relationships between demographic parameters and occurrence probability did not vary substantially across degrees of shade tolerance and regions. Although they were influenced by the uncertainty in the estimation of the demographic parameters, we found that r was generally negatively correlated with P occ , while N, and for most regions K, was generally positively correlated with P occ . Thus, in temperate forest trees the regions of highest occurrence

  13. Mathematical modeling of seed bank dynamics in population genetics

    OpenAIRE

    Martin, Anna

    2017-01-01

    We study the genealogical structure of samples from a population for which any givengeneration is made up of direct descendants from one randomly chosen previousgeneration. These occur in nature when there are seed banks or egg banks allowingan individual to leave offspring several generations in the future. Kaj et al. studied in2001 the case where any given generation is made up of descendants from severalprevious generations and showed how this temporal structure in the reproductionmechanis...

  14. Does probability of occurrence relate to population dynamics?

    Science.gov (United States)

    Thuiller, Wilfried; Münkemüller, Tamara; Schiffers, Katja H.; Georges, Damien; Dullinger, Stefan; Eckhart, Vincent M.; Edwards, Thomas C.; Gravel, Dominique; Kunstler, Georges; Merow, Cory; Moore, Kara; Piedallu, Christian; Vissault, Steve; Zimmermann, Niklaus E.; Zurell, Damaris; Schurr, Frank M.

    2014-01-01

    Hutchinson defined species' realized niche as the set of environmental conditions in which populations can persist in the presence of competitors. In terms of demography, the realized niche corresponds to the environments where the intrinsic growth rate (r) of populations is positive. Observed species occurrences should reflect the realized niche when additional processes like dispersal and local extinction lags do not have overwhelming effects. Despite the foundational nature of these ideas, quantitative assessments of the relationship between range-wide demographic performance and occurrence probability have not been made. This assessment is needed both to improve our conceptual understanding of species' niches and ranges and to develop reliable mechanistic models of species geographic distributions that incorporate demography and species interactions.The objective of this study is to analyse how demographic parameters (intrinsic growth rate r and carrying capacity K ) and population density (N ) relate to occurrence probability (Pocc ). We hypothesized that these relationships vary with species' competitive ability. Demographic parameters, density, and occurrence probability were estimated for 108 tree species from four temperate forest inventory surveys (Québec, western USA, France and Switzerland). We used published information of shade tolerance as indicators of light competition strategy, assuming that high tolerance denotes high competitive capacity in stable forest environments.Interestingly, relationships between demographic parameters and occurrence probability did not vary substantially across degrees of shade tolerance and regions. Although they were influenced by the uncertainty in the estimation of the demographic parameters, we found that r was generally negatively correlated with Pocc, while N, and for most regions K, was generally positively correlated with Pocc. Thus, in temperate forest trees the regions of highest occurrence

  15. Evolutionary dynamics of fluctuating populations with strong mutualism

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David

    2013-03-01

    Evolutionary game theory with finite interacting populations is receiving increased attention, including subtle phenomena associated with number fluctuations, i.e., ``genetic drift.'' Models of cooperation and competition often utilize a simplified Moran model, with a strictly fixed total population size. We explore a more general evolutionary model with independent fluctuations in the numbers of two distinct species, in a regime characterized by ``strong mutualism.'' The model has two absorbing states, each corresponding to fixation of one of the two species, and allows exploration of the interplay between growth, competition, and mutualism. When mutualism is favored, number fluctuations eventually drive the system away from a stable fixed point, characterized by cooperation, to one of the absorbing states. Well-mixed populations will thus be taken over by a single species in a finite time, despite the bias towards cooperation. We calculate both the fixation probability and the mean fixation time as a function of the initial conditions and carrying capacities in the strong mutualism regime, using the method of matched asymptotic expansions. Our results are compared to computer simulations.

  16. Population dynamics of mallards breeding in eastern Washington

    Science.gov (United States)

    Dugger, Bruce D.; Coluccy, John M.; Dugger, Katie M.; Fox, Trevor T.; Kraege, Donald K.; Petrie, Mark J.

    2016-01-01

    Variation in regional population trends for mallards breeding in the western United States indicates that additional research into factors that influence demographics could contribute to management and understanding the population demographics of mallards across North America. We estimated breeding incidence and adult female, nest, and brood survival in eastern Washington in 2006 and 2007 by monitoring female mallards with radio telemetry and tested how those parameters were influenced by study year (2006 vs. 2007), landscape type (agricultural vs. natural), and age (second year [SY] vs. after second year [ASY]). We also investigated the effects of female body condition and capture date on breeding incidence, and nest initiation date and hatch date on nest and brood survival, respectively. We included population parameters in a stage-based demographic model and conducted a perturbation analysis to identify which vital rates were most influential on population growth rate (λ). Adult female survival was best modeled with a constant weekly survival rate (0.994, SE = 0.003). Breeding incidence differed between years and was higher for birds in better body condition. Nest survival was higher for ASY females (0.276, SE = 0.118) than SY females (0.066, SE = 0.052), and higher on publicly managed lands (0.383, SE = 0.212) than agricultural (0.114, SE = 0.058) landscapes. Brood survival was best modeled with a constant rate for the 7-week monitoring period (0.50, SE = 0.155). The single variable having the greatest influence on λ was non-breeding season survival, but the combination of parameters from the breeding grounds explained a greater percent of the variance in λ. Mallard population growth rate was most sensitive to changes in non-breeding survival, nest success, brood survival, and breeding incidence. Future management decisions should focus on activities that improve these vital rates if managers want to increase the production of

  17. Modelling of population dynamics of red king crab using Bayesian approach

    Directory of Open Access Journals (Sweden)

    Bakanev Sergey ...

    2012-10-01

    Modeling population dynamics based on the Bayesian approach enables to successfully resolve the above issues. The integration of the data from various studies into a unified model based on Bayesian parameter estimation method provides a much more detailed description of the processes occurring in the population.

  18. Strong persistent growth differences govern individual performance and population dynamics in a tropical forest understorey palm

    NARCIS (Netherlands)

    Jansen, M.; Zuidema, P.A.; Anten, N.P.R.; Martínez-Ramos, M.

    2012-01-01

    1. Persistent variation in growth rate between individual plants can have strong effects on population dynamics as fast growers reach the reproductive size at an earlier age and thus potentially contribute more to population growth than slow growers. In tropical forests, such persistent growth

  19. Weed populations and crop rotations: exploring dynamics of a structured periodic system

    NARCIS (Netherlands)

    Mertens, S.K.; Bosch, F. van den; Heesterbeek, J.A.P.

    2002-01-01

    The periodic growing of a certain set of crops in a prescribed order, called a crop rotation, is considered to be an important tool for managing weed populations. Nevertheless, the effects of crop rotations on weed population dynamics are not well understood. Explanations for rotation effects on

  20. Population dynamics under increasing environmental variability: implications of climate change for ecological network design criteria

    NARCIS (Netherlands)

    Verboom, J.; Schippers, P.; Cormont, A.; Sterk, M.; Vos, C.C.; Opdam, P.F.M.

    2010-01-01

    There is growing evidence that climate change causes an increase in variation in conditions for plant and animal populations. This increase in variation, e.g. amplified inter-annual variability in temperature and rainfall has population dynamical consequences because it raises the variation in vital

  1. Adaptation dynamics of laboratory populations of Drosophila Melanogaster to low dose chronic ionizing irradiation

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Yushkova, E.A.

    2008-01-01

    In genetically non-uniform populations D. melanogaster in conditions of a chronic irradiation in a doze 10-11 about sGy/generation dynamics parameters of populations was investigated. It is established, that number of individuals in irradiated populations is lower, than in control. It is revealed, that viability of populations undergone to a chronic irradiation depends on their genotype. The gradual increase in fruitfulness, viability of individuals and decrease in a level of lethal mutations in a number of generations after of an irradiation in low doses is caused by adaptable opportunities of populations. (authors)

  2. A dynamic urban air pollution population exposure assessment study using model and population density data derived by mobile phone traffic

    Science.gov (United States)

    Gariazzo, Claudio; Pelliccioni, Armando; Bolignano, Andrea

    2016-04-01

    A dynamic city-wide air pollution exposure assessment study has been carried out for the urban population of Rome, Italy, by using time resolved population distribution maps, derived by mobile phone traffic data, and modelled air pollutants (NO2, O3 and PM2.5) concentrations obtained by an integrated air dispersion modelling system. More than a million of persons were tracked during two months (March and April 2015) for their position within the city and its surroundings areas, with a time resolution of 15 min and mapped over an irregular grid system with a minimum resolution of 0.26 × 0.34 Km2. In addition, demographics information (as gender and age ranges) were available in a separated dataset not connected with the total population one. Such BigData were matched in time and space with air pollution model results and then used to produce hourly and daily resolved cumulative population exposures during the studied period. A significant mobility of population was identified with higher population densities in downtown areas during daytime increasing of up to 1000 people/Km2 with respect to nigh-time one, likely produced by commuters, tourists and working age population. Strong variability (up to ±50% for NO2) of population exposures were detected as an effect of both mobility and time/spatial changing in pollutants concentrations. A comparison with the correspondent stationary approach based on National Census data, allows detecting the inability of latter in estimating the actual variability of population exposure. Significant underestimations of the amount of population exposed to daily PM2.5 WHO guideline was identified for the Census approach. Very small differences (up to a few μg/m3) on exposure were detected for gender and age ranges population classes.

  3. Community trust and household health: A spatially-based approach with evidence from rural Honduras.

    Science.gov (United States)

    Zarychta, Alan

    2015-12-01

    What is the relationship between community trust and household health? Scholars working to understand the effects of trust and social capital on human health tend to focus on individual characteristics or social environments, frequently without integrating these two dimensions. In light of this, the present paper makes contributions in both conceptualization and measurement. First, I develop a spatially-based approach for operationalizing community trust as the product of individual orientation and social environment. This approach highlights the need for a household to trust its neighbors and for those neighbors to reciprocate trust in order to constitute the psychological and material mechanisms critical for linking social context to individual health. Second, I illustrate the utility of this measure by evaluating the relationship between community trust and self-rated health status using an original population census survey from 2009 to 2010 for two municipalities in western Honduras (approximately 2800 households with a response rate of 94.9%). I implement spatial regression analysis and show that there is a positive and substantively meaningful relationship between community trust and household health; households that are trusting and surrounded by similarly trusting neighbors report better health status, while those in uncertain or mutually distrusting environments report worse health. The theory and results presented here suggest an important link between trust and social capital at the community level, which is particularly salient for rural regions in developing countries where health resources are scarce and community-based interventions are common. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Identifying Ancient Settlement Patterns through LiDAR in the Mosquitia Region of Honduras.

    Directory of Open Access Journals (Sweden)

    Christopher T Fisher

    Full Text Available The Mosquitia ecosystem of Honduras occupies the fulcrum between the American continents and as such constitutes a critical region for understanding past patterns of socio-political development and interaction. Heavy vegetation, rugged topography, and remoteness have limited scientific investigation. This paper presents prehistoric patterns of settlement and landuse for a critical valley within the Mosquitia derived from airborne LiDAR scanning and field investigation. We show that (i though today the valley is a wilderness it was densely inhabited in the past; (ii that this population was organized into a three-tiered system composed of 19 settlements dominated by a city; and, (iii that this occupation was embedded within a human engineered landscape. We also add to a growing body of literature that demonstrates the utility of LiDAR as means for rapid cultural assessments in undocumented regions for analysis and conservation. Our ultimate hope is for our work to promote protections to safeguard the unique and critically endangered Mosquitia ecosystem and other similar areas in need of preservation.

  5. Identifying Ancient Settlement Patterns through LiDAR in the Mosquitia Region of Honduras

    Science.gov (United States)

    Fernández-Diaz, Juan Carlos; Cohen, Anna S.; Neil Cruz, Oscar; Gonzáles, Alicia M.; Leisz, Stephen J.; Pezzutti, Florencia; Shrestha, Ramesh; Carter, William

    2016-01-01

    The Mosquitia ecosystem of Honduras occupies the fulcrum between the American continents and as such constitutes a critical region for understanding past patterns of socio-political development and interaction. Heavy vegetation, rugged topography, and remoteness have limited scientific investigation. This paper presents prehistoric patterns of settlement and landuse for a critical valley within the Mosquitia derived from airborne LiDAR scanning and field investigation. We show that (i) though today the valley is a wilderness it was densely inhabited in the past; (ii) that this population was organized into a three-tiered system composed of 19 settlements dominated by a city; and, (iii) that this occupation was embedded within a human engineered landscape. We also add to a growing body of literature that demonstrates the utility of LiDAR as means for rapid cultural assessments in undocumented regions for analysis and conservation. Our ultimate hope is for our work to promote protections to safeguard the unique and critically endangered Mosquitia ecosystem and other similar areas in need of preservation. PMID:27560962

  6. The coexistence of Baird's tapir (Tapirus bairdii) and indigenous hunters in northeastern Honduras.

    Science.gov (United States)

    Dunn, Marc; Estrada, Nereyda; Smith, Derek A

    2012-12-01

    The Baird's tapir (Tapirus bairdii) is a popular game species throughout Central America, particularly among indigenous populations, and is currently endangered. Research on Miskitu hunting was conducted over 4 months in a remote region in northeastern Honduras that overlaps with the Río Plátano Biosphere Reserve. The hunting zone was mapped together with hunters and interviews were conducted with elders and other community members about tapir hunting. Results show that tapir harvesting is targeted toward specific habitats at specific times of year. Harvest rates for one year suggest that tapir hunting in the area exceeds estimates of maximum sustainable production. Nevertheless, field surveys reveal the presence of tapir within 1 km of the community, and its harvest tends to be nearby, in both forested and agricultural landscapes, suggesting that the animal has not been depleted in the area. It appears that the existence of forest areas adjacent to the hunting zone that do not experience hunting, together with the anthropogenic habitats created through shifting cultivation, are factors that help explain the presence of tapirs in the area. The article concludes with a discussion regarding the potential positive role of indigenous hunters in tapir conservation throughout its distribution range. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

  7. A cross-sectional study of pediatric eye care perceptions in Ghana, Honduras, and India.

    Science.gov (United States)

    Ramai, Daryl; Elliott, Ryan; Goldin, Shoshanna; Pulisetty, Tejas

    2015-06-01

    Of the more than 1.4 million blind children worldwide, 75% live in developing countries. To reduce the prevalence of childhood blindness and associated diseases, attention is given to understanding the perceptions and level of awareness held by caregivers. This understanding can enable tailored health programs to reduce the global prevalence of blindness with increased efficiency. This study, which took place in Ghana, Honduras, and India, found that 95% of caregivers believed in the importance of eye exams for children, yet 66% of caregivers said that none of their children had ever received an eye exam. Participants' major reasons for not bringing their children included the belief that their child had no eye problems along with similar and unique socio-economic barriers. Further information was gained through the use of a five-question test on basic child eye care symptoms, which showed that out of the three country locations, the studied population in India had the least understanding about pediatric eye symptoms. Further analysis revealed significant gaps in understanding of general eye health while detected knowledge barriers provide evidence that fundamental misconceptions appear to be inhibiting caregivers' competence in facilitating their children's eye health. Copyright © 2014 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

  8. Prevalence of sensitization to inhalant allergens in a immunology department from Tegucigalpa, Honduras, 2016

    Directory of Open Access Journals (Sweden)

    Victoria Alejandra Gonzales-González

    2017-02-01

    Full Text Available Background: Allergic diseases are a public health problem; estimates indicate that between 30% and 40% of the world population is affected by some allergy. Knowing the prevalence of allergen sensitization allows for adequate diagnoses and treatments to be offered. In Honduras there are no studies available in pediatric patients. Objectives: The purpose of this research was to identify the most common types of sensitization in children and their correlation with the most common allergic diseases in patients on immunotherapy at the Maria Hospital of Pediatric Specialties. Methods: Cross-sectional, descriptive, retrospective study in which medical records and databases of patients on allergic immunotherapy at the Maria Hospital of Pediatric Specialties were reviewed between January 2015 and June 2016. Results: 215 children on immunotherapy were assessed; ages ranged from 3 to 18 years, with a mean of 10.8 years. Aeroallergen-positive epicutaneous tests were identified in 73.02%. The most common aeroallergens were Dermatophagoides farinae and Dermatophagoides pteronyssinus mix (96.74%, American cockroach 37.21%, and Aspergillus fumigatus and Homodenderum cladosporioides (16.28%. Conclusions: House dust mites and American cockroach were the most common causes of sensitization in patients on immunotherapy.

  9. Identifying Ancient Settlement Patterns through LiDAR in the Mosquitia Region of Honduras.

    Science.gov (United States)

    Fisher, Christopher T; Fernández-Diaz, Juan Carlos; Cohen, Anna S; Neil Cruz, Oscar; Gonzáles, Alicia M; Leisz, Stephen J; Pezzutti, Florencia; Shrestha, Ramesh; Carter, William

    2016-01-01

    The Mosquitia ecosystem of Honduras occupies the fulcrum between the American continents and as such constitutes a critical region for understanding past patterns of socio-political development and interaction. Heavy vegetation, rugged topography, and remoteness have limited scientific investigation. This paper presents prehistoric patterns of settlement and landuse for a critical valley within the Mosquitia derived from airborne LiDAR scanning and field investigation. We show that (i) though today the valley is a wilderness it was densely inhabited in the past; (ii) that this population was organized into a three-tiered system composed of 19 settlements dominated by a city; and, (iii) that this occupation was embedded within a human engineered landscape. We also add to a growing body of literature that demonstrates the utility of LiDAR as means for rapid cultural assessments in undocumented regions for analysis and conservation. Our ultimate hope is for our work to promote protections to safeguard the unique and critically endangered Mosquitia ecosystem and other similar areas in need of preservation.

  10. The population dynamics of cancer: a Darwinian perspective.

    Science.gov (United States)

    Vineis, Paolo; Berwick, Marianne

    2006-10-01

    Carcinogenesis, at least for some types of cancer, can be interpreted as the consequence of selection of mutated cells similar to what, in the theory of evolution, occurs at the population level. Instead of considering a population of organisms, we can refer to a population of cells belonging to multicellular organisms. Many carcinogens are mutagens, and the observed geographic distribution of cancer is, at least in part, attributable to environmental mutagens. However, the rapid change in risk for some cancers after migration suggests that carcinogenesis involves--in addition to mutations--some late event that most probably consists of the selection of cells already carrying mutations. We review a few examples of such selective pressures: finasteride in prostate cancer, vitamin supplementation in smokers, acquired resistance to chemotherapy, peripheral resistance to insulin, and sunlight and mutations in melanoma. A disease model for such a hypothesis is represented by Paroxysmal Nocturnal Hemoglobinuria (PNH). Mutations can be present at birth, as in the case of PNH, and can have a frequency much higher than the occurrence of the corresponding disease (PNH or lymphocytic leukaemia in children). However, PNH does not require a mutator phenotype, only a mutant phenotype followed by selection. A characteristic feature of cancer, instead, is likely to be the development of the mutator phenotype. We propose a 'Darwinian' model of carcinogenesis. If the model is correct, it suggests that prevention is more complex than avoiding exposure to mutagens. Mutations and genetic instability can be already present at birth. Mutations can be selected in the course of life if they increase survival advantage of the cell under certain environmental circumstances. In addition, gene-environment interactions cannot be interpreted according to a simplified linear model (based on the 'analysis of variance' concept); experimental work suggests that a more comprehensive non

  11. Molecular characterization of microbial population dynamics during sildenafil citrate degradation.

    Science.gov (United States)

    De Felice, Bruna; Argenziano, Carolina; Guida, Marco; Trifuoggi, Marco; Russo, Francesca; Condorelli, Valerio; Inglese, Mafalda

    2009-02-01

    Little is known about pharmaceutical and personal care products pollutants (PPCPs), but there is a growing interest in how they might impact the environment and microbial communities. The widespread use of Viagra (sildenafil citrate) has attracted great attention because of the high usage rate, the unpredictable disposal and the unknown potential effects on wildlife and the environment. Until now information regarding the impact of Viagra on microbial community in water environment has not been reported. In this research, for the first time, the genetic profile of the microbial community, developing in a Viagra polluted water environment, was evaluated by means of the 16S and 18S rRNA genes, for bacteria and fungi, respectively, amplified by polymerase chain reaction (PCR) and separated using the denaturing gradient gel electrophoresis (DGGE) technique. The DGGE results revealed a complex microbial community structure with most of the population persisting throughout the experimental period. DNA sequences from bands observed in the different denaturing gradient gel electrophoresis profiles exhibited the highest degree of identity to uncultured bacteria and fungi found previously mainly in polluted environmental and treating bioreactors. Biotransformation ability of sildenafil citrate by the microbial pool was studied and the capability of these microorganisms to detoxify a polluted water ecosystem was assessed. The bacterial and fungal population was able to degrade sildenafil citrate entirely. Additionally, assays conducted on Daphnia magna, algal growth inhibition assay and cell viability determination on HepG2 human cells showed that biotransformation products obtained from the bacterial growth was not toxic. The higher removal efficiency for sildenafil citrate and the lack of toxicity by the biotransformation products obtained showed that the microbial community identified here represented a composite population that might have biotechnological relevance to

  12. Population dynamics of bowfin in a south Georgia reservoir: latitudinal comparisons of population structure, growth, and mortality

    Science.gov (United States)

    Porter, Nicholas J.; Bonvechio, Timothy F.; McCormick, Joshua L.; Quist, Michael

    2014-01-01

    The objectives of this study were to evaluate the population dynamics of bowfin (Amia calva) in Lake Lindsay Grace, Georgia, and to compare those dynamics to other bowfin populations. Relative abundance of bowfin sampled in 2010 in Lake Lindsay Grace was low and variable (mean±SD; 2.7±4.7 fish per hour of electrofishing). Total length (TL) of bowfin collected in Lake Lindsay Grace varied from 233–683 mm. Age of bowfin in Lake Lindsay Grace varied from 0–5 yr. Total annual mortality (A) was estimated at 68%. Both sexes appeared to be fully mature by age 2 with gonadosomatic index values above 8 for females and close to 1 for males. The majority of females were older, longer, and heavier than males. Bowfin in Lake Lindsay Grace had fast growth up to age 4 and higher total annual mortality than the other populations examined in this study. A chi-square test indicated that size structure of bowfin from Lake Lindsay Grace was different than those of a Louisiana population and two bowfin populations from the upper Mississippi River. To further assess bowfin size structure, we proposed standard length (i.e., TL) categories: stock (200 mm, 8 inches), quality (350 mm, 14 inches), preferred (460 mm, 18 inches), memorable (560 mm, 22, inches), and trophy (710 mm, 28 inches). Because our knowledge of bowfin ecology is limited, additional understanding of bowfin population dynamics provides important insight that can be used in management of bowfin across their distribution.

  13. Reinforcement learning in complementarity game and population dynamics.

    Science.gov (United States)

    Jost, Jürgen; Li, Wei

    2014-02-01

    We systematically test and compare different reinforcement learning schemes in a complementarity game [J. Jost and W. Li, Physica A 345, 245 (2005)] played between members of two populations. More precisely, we study the Roth-Erev, Bush-Mosteller, and SoftMax reinforcement learning schemes. A modified version of Roth-Erev with a power exponent of 1.5, as opposed to 1 in the standard version, performs best. We also compare these reinforcement learning strategies with evolutionary schemes. This gives insight into aspects like the issue of quick adaptation as opposed to systematic exploration or the role of learning rates.

  14. Population dynamics of spotted owls in the Sierra Nevada, California

    Science.gov (United States)

    Blakesley, J.A.; Seamans, M.E.; Conner, M.M.; Franklin, A.B.; White, Gary C.; Gutierrez, R.J.; Hines, J.E.; Nichols, J.D.; Munton, T.E.; Shaw, D.W.H.; Keane, J.J.; Steger, G.N.; McDonald, T.L.

    2010-01-01

    The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California, USA, from 1990 to 2005 to assist a listing evaluation by the United States Fish and Wildlife Service. Our study areas (from N to S) were on the Lassen National Forest (LAS), Eldorado National Forest (ELD), Sierra National Forest (SIE), and Sequoia and Kings Canyon National Parks (SKC). These study areas represented a broad spectrum of habitat and management conditions in these mountain ranges. We estimated apparent survival probability, reproductive output, and rate of population change for spotted owls on individual study areas and for all study areas combined (meta-analysis) using model selection or model-averaging based on maximum-likelihood estimation. We followed a formal protocol to conduct this analysis that was similar to other spotted owl meta-analyses. Consistency of field and analytical methods among our studies reduced confounding methodological effects when evaluating results. We used 991 marked spotted owls in the analysis of apparent survival. Apparent survival probability was higher for adult than for subadult owls. There was little difference in apparent survival between male and female owls. Model-averaged mean estimates of apparent survival probability of adult owls varied from 0.811 ?? 0.021 for females at LAS to 0.890 ?? 0.016 for males at SKC. Apparent survival increased over time for owls of all age classes at LAS and SIE, for adults at ELD, and for second-year subadults and adults at SKC. The meta-analysis of apparent survival, which included only adult owls, confirmed an increasing trend in survival over time. Survival rates were higher for owls on SKC than on the other study areas. We analyzed data

  15. Types of population dynamics in settlements of Zaplanje area

    Directory of Open Access Journals (Sweden)

    Martinović Marija

    2012-01-01

    Full Text Available The aim of this article is to present the main directions of changes in the spatial-demographic settlements organization of Zaplanje, which, due to rapid demographic recession since the 60s of the 20th century, is the strongest depopulation area with the oldest population in Serbia. This research aims is to determine the main types of changes in demographic development of the settlements and indirectly reveals key issues of the sustainable development of Zaplanje settlements and revitalization of villages. [Projekat Ministarstva nauke Republike Srbije, br. 176017

  16. Phylogeography, population dynamics, and molecular evolution of European bat lyssaviruses

    DEFF Research Database (Denmark)

    Davis, P.L.; Holmes, E.C.; Larrous, F.

    2005-01-01

    origin, and population growth rates of EBLV-1. Our study encompassed data from 12 countries collected over a time span of 35 years and focused on the glycoprotein (G) and nucleoprotein (N) genes. We show that although the two subtypes of EBLV-1-EBLV-1a and EBLV-lb-have both grown at a low exponential...... in EBLV-1b. Our inferred rate of nucleotide substitution in EBLV-1, approximately 5 X 10(-5) substitutions per site per year, was also one of the lowest recorded for RNA viruses and implied that the current genetic diversity in the virus arose 500 to 750 years ago. We propose that the slow evolution...

  17. Direct characterization of chaotic and stochastic dynamics in a population model with strong periodicity

    International Nuclear Information System (INIS)

    Tung Wenwen; Qi Yan; Gao, J.B.; Cao Yinhe; Billings, Lora

    2005-01-01

    In recent years it has been increasingly recognized that noise and determinism may have comparable but different influences on population dynamics. However, no simple analysis methods have been introduced into ecology which can readily characterize those impacts. In this paper, we study a population model with strong periodicity and both with and without noise. The noise-free model generates both quasi-periodic and chaotic dynamics for certain parameter values. Due to the strong periodicity, however, the generated chaotic dynamics have not been satisfactorily described. The dynamics becomes even more complicated when there is noise. Characterizing the chaotic and stochastic dynamics in this model thus represents a challenging problem. Here we show how the chaotic dynamics can be readily characterized by the direct dynamical test for deterministic chaos developed by [Gao JB, Zheng ZM. Europhys. Lett. 1994;25:485] and how the influence of noise on quasi-periodic motions can be characterized as asymmetric diffusions wandering along the quasi-periodic orbit. It is hoped that the introduced methods will be useful in studying other population models as well as population time series obtained both in field and laboratory experiments

  18. The basic approach to age-structured population dynamics models, methods and numerics

    CERN Document Server

    Iannelli, Mimmo

    2017-01-01

    This book provides an introduction to age-structured population modeling which emphasises the connection between mathematical theory and underlying biological assumptions. Through the rigorous development of the linear theory and the nonlinear theory alongside numerics, the authors explore classical equations that describe the dynamics of certain ecological systems. Modeling aspects are discussed to show how relevant problems in the fields of demography, ecology, and epidemiology can be formulated and treated within the theory. In particular, the book presents extensions of age-structured modelling to the spread of diseases and epidemics while also addressing the issue of regularity of solutions, the asymptotic behaviour of solutions, and numerical approximation. With sections on transmission models, non-autonomous models and global dynamics, this book fills a gap in the literature on theoretical population dynamics. The Basic Approach to Age-Structured Population Dynamics will appeal to graduate students an...

  19. Effects of wind farms on harbour porpoise behaviour and population dynamics

    DEFF Research Database (Denmark)

    Nabe-Nielsen, Jacob; Tougaard, Jakob; Teilmann, Jonas

    We developed an individual-based simulation model in order to study the cumulative impacts of wind farms and ship traffic on the long-term survival and population dynamics of the harbour porpoise (Phocoena phocoena) in Kattegat and the Belt Seas. The model is based on knowl- edge of the porpoises...... at distances >1 km. Our simulations suggest that operating wind farms and wind farms under construction do not affect the size or dynamics of the harbour porpoise population in Kattegat. Ship traffic may, in contrast, cause the population size to decrease....

  20. The population and evolutionary dynamics of homologous gene recombination in bacterial populations.

    Directory of Open Access Journals (Sweden)

    Bruce R Levin

    2009-08-01

    Full Text Available In bacteria, recombination is a rare event, not a part of the reproductive process. Nevertheless, recombination -- broadly defined to include the acquisition of genes from external sources, i.e., horizontal gene transfer (HGT -- plays a central role as a source of variation for adaptive evolution in many species of bacteria. Much of niche expansion, resistance to antibiotics and other environmental stresses, virulence, and other characteristics that make bacteria interesting and problematic, is achieved through the expression of genes and genetic elements obtained from other populations of bacteria of the same and different species, as well as from eukaryotes and archaea. While recombination of homologous genes among members of the same species has played a central role in the development of the genetics and molecular biology of bacteria, the contribution of homologous gene recombination (HGR to bacterial evolution is not at all clear. Also, not so clear are the selective pressures responsible for the evolution and maintenance of transformation, the only bacteria-encoded form of HGR. Using a semi-stochastic simulation of mutation, recombination, and selection within bacterial populations and competition between populations, we explore (1 the contribution of HGR to the rate of adaptive evolution in these populations and (2 the conditions under which HGR will provide a bacterial population a selective advantage over non-recombining or more slowly recombining populations. The results of our simulation indicate that, under broad conditions: (1 HGR occurring at rates in the range anticipated for bacteria like Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae, and Bacillus subtilis will accelerate the rate at which a population adapts to environmental conditions; (2 once established in a population, selection for this capacity to increase rates of adaptive evolution can maintain bacteria-encoded mechanisms of recombination and prevent

  1. Demography of the Early Neolithic Population in Central Balkans: Population Dynamics Reconstruction Using Summed Radiocarbon Probability Distributions.

    Directory of Open Access Journals (Sweden)

    Marko Porčić

    Full Text Available The Central Balkans region is of great importance for understanding the spread of the Neolithic in Europe but the Early Neolithic population dynamics of the region is unknown. In this study we apply the method of summed calibrated probability distributions to a set of published radiocarbon dates from the Republic of Serbia in order to reconstruct population dynamics in the Early Neolithic in this part of the Central Balkans. The results indicate that there was a significant population growth after ~6200 calBC, when the Neolithic was introduced into the region, followed by a bust at the end of the Early Neolithic phase (~5400 calBC. These results are broadly consistent with the predictions of the Neolithic Demographic Transition theory and the patterns of population booms and busts detected in other regions of Europe. These results suggest that the cultural process that underlies the patterns observed in Central and Western Europe was also in operation in the Central Balkan Neolithic and that the population increase component of this process can be considered as an important factor for the spread of the Neolithic as envisioned in the demic diffusion hypothesis.

  2. Potential impact of harvesting on the population dynamics of two epiphytic bromeliads

    Science.gov (United States)

    Toledo-Aceves, Tarin; Hernández-Apolinar, Mariana; Valverde, Teresa

    2014-08-01

    Large numbers of epiphytes are extracted from cloud forests for ornamental use and illegal trade in Latin America. We examined the potential effects of different harvesting regimes on the population dynamics of the epiphytic bromeliads Tillandsia multicaulis and Tillandsia punctulata. The population dynamics of these species were studied over a 2-year period in a tropical montane cloud forest in Veracruz, Mexico. Prospective and retrospective analyses were used to identify which demographic processes and life-cycle stages make the largest relative contribution to variation in population growth rate (λ). The effect of simulated harvesting levels on population growth rates was analysed for both species. λ of both populations was highly influenced by survival (stasis), to a lesser extent by growth, and only slightly by fecundity. Vegetative growth played a central role in the population dynamics of these organisms. The λ value of the studied populations did not differ significantly from unity: T. multicaulis λ (95% confidence interval) = 0.982 (0.897-1.060) and T. punctulata λ = 0.967 (0.815-1.051), suggesting population stability. However, numerical simulation of different levels of extraction showed that λ would drop substantially even under very low (2%) harvesting levels. Matrix analysis revealed that T. multicaulis and T. punctulata populations are likely to decline and therefore commercial harvesting would be unsustainable. Based on these findings, management recommendations are outlined.

  3. An obligatory bacterial mutualism in a multi-drug environment exhibits strong oscillatory population dynamics

    Science.gov (United States)

    Conwill, Arolyn; Yurtsev, Eugene; Gore, Jeff

    2014-03-01

    A common mechanism of antibiotic resistance in bacteria involves the production of an enzyme that inactivates the antibiotic. By inactivating the antibiotic, resistant cells can protect other cells in the population that would otherwise be sensitive to the drug. In a multidrug environment, an obligatory mutualism arises because populations of different strains rely on each other to breakdown antibiotics in the environment. Here, we experimentally track the population dynamics of two E. coli strains in the presence of two different antibiotics: ampicillin and chloramphenicol. Together the strains are able to grow in antibiotic concentrations that inhibit growth of either one of the strains alone. Although mutualisms are often thought to stabilize population dynamics, we observe strong oscillatory dynamics even when there is long-term coexistence between the two strains. We expect that our results will provide insight into the evolution of antibiotic resistance and, more generally, the evolutionary origin of phenotypic diversity, cooperation, and ecological stability.

  4. Spatial and temporal dynamics of the genetic organization of small mammal populations

    International Nuclear Information System (INIS)

    Smith, M.H.; Manlove, M.N.; Joule, J.

    1978-01-01

    A functional population is a group of organisms and their offspring that contributes to a common gene pool within a certain area and time period. It is also the unit of evolution and should be viewed both in quantitative and qualitative terms. Selection, drift, dispersal, and mutation can alter the composition of populations. Spatial heterogeneity in allele frequencies argues for a conceptual model that has a series of relatively small populations semi-isolated from one another. Because of the relatively high levels of genetic variability characteristic of most mammalian species, significant amounts of gene flow between these spatially subdivided populations must occur when longer time periods are considered. Fluctuations in the genetic structure of populations seem to be important in altering the fitness of the individuals within the populations. The interaction of populations through gene flow is important in changing the levels of intrapopulational genetic variability. Populations can be characterized as existing on a continuum from relatively stable to unstable numbers and by other associated changes in their characteristics. Temporal changes in allele frequency occur in a variety of mammals. Conceptually, a species can be viewed as a series of dynamic populations that vary in numbers and quality in both a spatial and temporal context even over short distances and time periods. Short term changes in the quality of individuals in a population can be important in altering the short term dynamics of a population

  5. Climate effects and feedback structure determining weed population dynamics in a long-term experiment.

    Science.gov (United States)

    Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

    2012-01-01

    Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements.

  6. Climate Effects and Feedback Structure Determining Weed Population Dynamics in a Long-Term Experiment

    Science.gov (United States)

    Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

    2012-01-01

    Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements. PMID:22272362

  7. Climate effects and feedback structure determining weed population dynamics in a long-term experiment.

    Directory of Open Access Journals (Sweden)

    Mauricio Lima

    Full Text Available Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors. Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements.

  8. Population dynamics and habitat sharing of natural populations of Caenorhabditis elegans and C. briggsae

    Directory of Open Access Journals (Sweden)

    Félix Marie-Anne

    2012-06-01

    Full Text Available Abstract Background The nematode Caenorhabditis elegans is a major model organism in laboratory biology. Very little is known, however, about its ecology, including where it proliferates. In the past, C. elegans was mainly isolated from human-made compost heaps, where it was overwhelmingly found in the non-feeding dauer diapause stage. Results C. elegans and C. briggsae were found in large, proliferating populations in rotting plant material (fruits and stems in several locations in mainland France. Both species were found to co-occur in samples isolated from a given plant species. Population counts spanned a range from one to more than 10,000 Caenorhabditis individuals on a single fruit or stem. Some populations with an intermediate census size (10 to 1,000 contained no dauer larvae at all, whereas larger populations always included some larvae in the pre-dauer or dauer stages. We report on associated micro-organisms, including pathogens. We systematically sampled a spatio-temporally structured set of rotting apples in an apple orchard in Orsay over four years. C. elegans and C. briggsae were abundantly found every year, but their temporal distributions did not coincide. C. briggsae was found alone in summer, whereas both species co-occurred in early fall and C. elegans was found alone in late fall. Competition experiments in the laboratory at different temperatures show that C. briggsae out-competes C. elegans at high temperatures, whereas C. elegans out-competes C. briggsae at lower temperatures. Conclusions C. elegans and C. briggsae proliferate in the same rotting vegetal substrates. In contrast to previous surveys of populations in compost heaps, we found fully proliferating populations with no dauer larvae. The temporal sharing of the habitat by the two species coincides with their temperature preference in the laboratory, with C. briggsae populations growing faster than C. elegans at higher temperatures, and vice at lower temperatures.

  9. Understanding long-term fruit fly (Diptera: Tephritidae) population dynamics: implications for areawide management.

    Science.gov (United States)

    Aluja, Martín; Ordano, Mariano; Guillén, Larissa; Rull, Juan

    2012-06-01

    Fruit flies (Diptera: Tephritidae) are devastating agricultural pests worldwide but studies on their long-term population dynamics are sparse. Our aim was to determine the mechanisms driving long-term population dynamics as a prerequisite for ecologically based areawide pest management. The population density of three pestiferous Anastrepha species [Anastrepha ludens (Loew), Anastrepha obliqua (Macquart), and Anastrepha serpentina (Wiedemann)] was determined in grapefruit (Citrus x paradisi Macfad.), mango (Mangifera indica L.), and sapodilla [Manilkara zapota (L.) P. Royen] orchards in central Veracruz, México, on a weekly basis over an 11-yr period. Fly populations exhibited relatively stable dynamics over time. Population dynamics were mainly driven by a direct density-dependent effect and a seasonal feedback process. We discovered direct and delayed influences that were correlated with both local (rainfall and air temperature) and global climatic variation (El Niño Southern Oscillation [ENSO] and North Atlantic Oscillation [NAO]), and detected differences among species and location of orchards with respect to the magnitude and nature (linear or nonlinear) of the observed effects, suggesting that highly mobile pest outbreaks become uncertain in response to significant climatic events at both global and local levels. That both NAO and ENSO affected Anastrepha population dynamics, coupled with the high mobility of Anastrepha adults and the discovery that when measured as rate of population change, local population fluctuations exhibited stable dynamics over time, suggests potential management scenarios for the species studied lie beyond the local scale and should be approached from an areawide perspective. Localized efforts, from individual growers will probably prove ineffective, and nonsustainable.

  10. Global dynamics of oscillator populations under common noise

    Science.gov (United States)

    Braun, W.; Pikovsky, A.; Matias, M. A.; Colet, P.

    2012-07-01

    Common noise acting on a population of identical oscillators can synchronize them. We develop a description of this process which is not limited to the states close to synchrony, but provides a global picture of the evolution of the ensembles. The theory is based on the Watanabe-Strogatz transformation, allowing us to obtain closed stochastic equations for the global variables. We show that at the initial stage, the order parameter grows linearly in time, while at the later stages the convergence to synchrony is exponentially fast. Furthermore, we extend the theory to nonidentical ensembles with the Lorentzian distribution of natural frequencies and determine the stationary values of the order parameter in dependence on driving noise and mismatch.

  11. Optimal superadiabatic population transfer and gates by dynamical phase corrections

    Science.gov (United States)

    Vepsäläinen, A.; Danilin, S.; Paraoanu, G. S.

    2018-04-01

    In many quantum technologies adiabatic processes are used for coherent quantum state operations, offering inherent robustness to errors in the control parameters. The main limitation is the long operation time resulting from the requirement of adiabaticity. The superadiabatic method allows for faster operation, by applying counterdiabatic driving that corrects for excitations resulting from the violation of the adiabatic condition. In this article we show how to construct the counterdiabatic Hamiltonian in a system with forbidden transitions by using two-photon processes and how to correct for the resulting time-dependent ac-Stark shifts in order to enable population transfer with unit fidelity. We further demonstrate that superadiabatic stimulated Raman passage can realize a robust unitary NOT-gate between the ground state and the second excited state of a three-level system. The results can be readily applied to a three-level transmon with the ladder energy level structure.

  12. Population dynamics of the Kaminuriak caribou herd, 1968 - 1985

    Directory of Open Access Journals (Sweden)

    Douglas C. Heard

    1986-06-01

    Full Text Available The Kaminuraik caribou herd apparently declined from about 120 000 animals in 1950 to 63 000 in 1968. Beginning in 1968 documentation of herd trend was based on the estimate of the number of breeding (pregnant and post-partum females on the calving ground during the birth peak. It appeared as if we understood the basic population processes responsible for the decline when we correctly predicted a drop from 14 800 breeding females in 1977 to 13 000 in 1980. However a three-fold increase, to 41 000 breeding females in 1982, and continued growth thereafter, was unanticipated. Most of that increase must have resulted from an immigration of cows to the herd's traditional calving ground around Kaminuriak Lake, although increased birth rates, and increased survival rates also contributed to herd growth. Immigrant cows probably came from the northeastern mainland of the NWT

  13. Ecotypic variation in population dynamics of reintroduced bighorn sheep

    Science.gov (United States)

    Bleich, Vernon C.; Sargeant, Glen A.; Wiedmann, Brett P.

    2018-01-01

    Selection of bighorn sheep (Ovis canadensis) for translocation historically has been motivated by preservation of subspecific purity rather than by adaptation of source stocks to similar environments. Our objective was to estimate cause‐specific, annual, and age‐specific mortality of introduced bighorn sheep that originated at low elevations in southern British Columbia, Canada (BC ecotype), or in the Missouri River Breaks region of central Montana, USA (MT ecotype). In North Dakota, USA, mortality was similar and typically low for adult female bighorn sheep from Montana (0.09 ± 0.029 [SE]) and British Columbia (0.08 ± 0.017) during 2000–2016. Median life expectancy was 11 years for females that reached adulthood (2 yrs old); however, mortality accelerated with age and reached 86% by age 16. Mortalities resulted primarily from low rates of predation, disease, accidents, and unknown natural causes (<0.04 [upper 90% CI]). Similar survival rates of female bighorn sheep from female bighorn sheep from British Columbia and Montana, coupled with greater recruitment of bighorn sheep from Montana, resulted in a greater projected rate of increase for the MT ecotype (λ = 1.21) than for the BC ecotype (1.02), and a more youthful age structure. These results support translocation of bighorn sheep from areas that are environmentally similar to areas that will be stocked. Potential benefits include more rapid population growth, greater resilience to and more rapid recovery from density‐independent losses, an increased possibility that rapidly growing populations will expand into adjacent habitat, increased hunter opportunity, increased connectivity among herds, and a more complete restoration of ecosystem processes.

  14. Ecotypic variation in population dynamics of reintroduced bighorn sheep

    Science.gov (United States)

    Bleich, Vernon C.; Sargeant, Glen A.; Wiedmann, Brett P.

    2018-01-01

    Selection of bighorn sheep (Ovis canadensis) for translocation historically has been motivated by preservation of subspecific purity rather than by adaptation of source stocks to similar environments. Our objective was to estimate cause‐specific, annual, and age‐specific mortality of introduced bighorn sheep that originated at low elevations in southern British Columbia, Canada (BC ecotype), or in the Missouri River Breaks region of central Montana, USA (MT ecotype). In North Dakota, USA, mortality was similar and typically low for adult female bighorn sheep from Montana (0.09 ± 0.029 [SE]) and British Columbia (0.08 ± 0.017) during 2000–2016. Median life expectancy was 11 years for females that reached adulthood (2 yrs old); however, mortality accelerated with age and reached 86% by age 16. Mortalities resulted primarily from low rates of predation, disease, accidents, and unknown natural causes (recruitment of bighorn sheep from Montana, resulted in a greater projected rate of increase for the MT ecotype (λ = 1.21) than for the BC ecotype (1.02), and a more youthful age structure. These results support translocation of bighorn sheep from areas that are environmentally similar to areas that will be stocked. Potential benefits include more rapid population growth, greater resilience to and more rapid recovery from density‐independent losses, an increased possibility that rapidly growing populations will expand into adjacent habitat, increased hunter opportunity, increased connectivity among herds, and a more complete restoration of ecosystem processes.

  15. Encuesta nacional de ceguera y deficiencia visual evitables en Honduras

    Directory of Open Access Journals (Sweden)

    Doris Alvarado

    2014-11-01

    Full Text Available OBJETIVO: Determinar la prevalencia de ceguera y deficiencia visual en Honduras, sus causas y la respuesta que los servicios de salud están dando a la creciente demanda. MÉTODOS: Estudio poblacional transversal realizado entre junio y diciembre de 2013 mediante la metodología estándar de evaluación rápida de ceguera evitable. Se realizó un muestreo aleatorio en 63 conglomerados de 50 personas de 50 años o más, representativo de todo el país. Se evaluó la agudeza visual (AV mediante una cartilla de Snellen y el estado del cristalino y del polo posterior por oftalmoscopía directa. Se calculó la cobertura de cirugía de catarata y se evaluó su calidad, las causas de tener AV < 20/60 y las barreras para acceder al tratamiento quirúrgico. RESULTADOS: Se examinaron 2 999 personas (95,2% del total previsto. La prevalencia de ceguera fue de 1,9% (intervalo de confianza de 95%: 1,4-2,4% y 82,2% de esos casos era evitable. La catarata no operada fue la causa principal de ceguera (59,2%, seguida del glaucoma (21,1%. Los errores de refracción no corregidos fueron la principal causa de deficiencia visual, tanto severa (19,7% como moderada (58,6%. La cobertura de cirugía de catarata fue de 75,2%. De los ojos operados de catarata, 62,5% alcanzó una AV ≥ 20/60 con la corrección disponible. Las principales barreras para someterse a la cirugía de catarata fueron el costo (27,7% y la falta de disponibilidad o de acceso geográfico al tratamiento (24,6%. CONCLUSIONES: La prevalencia de ceguera y deficiencia visual en Honduras es similar a la de otros países latinoamericanos. Mejorar la capacidad resolutiva de los servicios oftalmológicos, especialmente de cirugía de catarata, desarrollar los servicios ópticos y la atención ocular incorporada en la atención primaria en salud, podrían resolver el 67% de los casos de ceguera.

  16. Dynamic of age structure and the number of population in Ozersk and affecting factors

    International Nuclear Information System (INIS)

    Panchenko, O.; Rtischeva, M.

    2000-01-01

    The aim of this work was an evaluation of the dynamics of age structure and population for the city of Ozyorsk, based in connection with creation of the nuclear plant Mayak, the 'first-born' of the Russian atomic industry. The obtained results indicate that since 1950 demographic processes in Ozyorsk were more favorable, in spite of fact that it was in this period workers of Mayak nuclear plant and population as a whole, got comparatively greater radiation doses than in the following years. However, dynamics the number of population has an unfavorable trend to reduce, connected with sharp worsening of social-economic situation in the town as a whole, as a result of the economic reforms in the country. Reduction of the number of population in the town is expressed by the negative natural growth and by reducing migration processes, which resulted in sharp decrease of the general growth of population, and in its stopping in 1998. (authors)

  17. Note on the Honduras Radio Schools (ACPH--Accion Cultural Popular Hondureno). IEC Discussion Paper. Appendix 4.

    Science.gov (United States)

    Young, Michael

    This report on the radio schools in Honduras, Central America, includes (1) an account of an afternoon session of the radio school's Primary Equivalence Programme (PEPA), including a testimonial of a student and a statement regarding the importance of the monitors; (2) information on the social background of Honduras; (3) an historical account of…

  18. A Theoretical Approach to Understanding Population Dynamics with Seasonal Developmental Durations

    Science.gov (United States)

    Lou, Yijun; Zhao, Xiao-Qiang

    2017-04-01

    There is a growing body of biological investigations to understand impacts of seasonally changing environmental conditions on population dynamics in various research fields such as single population growth and disease transmission. On the other side, understanding the population dynamics subject to seasonally changing weather conditions plays a fundamental role in predicting the trends of population patterns and disease transmission risks under the scenarios of climate change. With the host-macroparasite interaction as a motivating example, we propose a synthesized approach for investigating the population dynamics subject to seasonal environmental variations from theoretical point of view, where the model development, basic reproduction ratio formulation and computation, and rigorous mathematical analysis are involved. The resultant model with periodic delay presents a novel term related to the rate of change of the developmental duration, bringing new challenges to dynamics analysis. By investigating a periodic semiflow on a suitably chosen phase space, the global dynamics of a threshold type is established: all solutions either go to zero when basic reproduction ratio is less than one, or stabilize at a positive periodic state when the reproduction ratio is greater than one. The synthesized approach developed here is applicable to broader contexts of investigating biological systems with seasonal developmental durations.

  19. Analysis of Ant Colony Optimization and Population-Based Evolutionary Algorithms on Dynamic Problems

    DEFF Research Database (Denmark)

    Lissovoi, Andrei

    the dynamic optimum for finite alphabets up to size μ, while MMAS is able to do so for any finite alphabet size. Parallel Evolutionary Algorithms on Maze. We prove that while a (1 + λ) EA is unable to track the optimum of the dynamic fitness function Maze for offspring population size up to λ = O(n1-ε......This thesis presents new running time analyses of nature-inspired algorithms on various dynamic problems. It aims to identify and analyse the features of algorithms and problem classes which allow efficient optimization to occur in the presence of dynamic behaviour. We consider the following...... settings: λ-MMAS on Dynamic Shortest Path Problems. We investigate how in-creasing the number of ants simulated per iteration may help an ACO algorithm to track optimum in a dynamic problem. It is shown that while a constant number of ants per-vertex is sufficient to track some oscillations, there also...

  20. Elevated nonlinearity as an indicator of shifts in the dynamics of populations under stress.

    Science.gov (United States)

    Dakos, Vasilis; Glaser, Sarah M; Hsieh, Chih-Hao; Sugihara, George

    2017-03-01

    Populations occasionally experience abrupt changes, such as local extinctions, strong declines in abundance or transitions from stable dynamics to strongly irregular fluctuations. Although most of these changes have important ecological and at times economic implications, they remain notoriously difficult to detect in advance. Here, we study changes in the stability of populations under stress across a variety of transitions. Using a Ricker-type model, we simulate shifts from stable point equilibrium dynamics to cyclic and irregular boom-bust oscillations as well as abrupt shifts between alternative attractors. Our aim is to infer the loss of population stability before such shifts based on changes in nonlinearity of population dynamics. We measure nonlinearity by comparing forecast performance between linear and nonlinear models fitted on reconstructed attractors directly from observed time series. We compare nonlinearity to other suggested leading indicators of instability (variance and autocorrelation). We find that nonlinearity and variance increase in a similar way prior to the shifts. By contrast, autocorrelation is strongly affected by oscillations. Finally, we test these theoretical patterns in datasets of fisheries populations. Our results suggest that elevated nonlinearity could be used as an additional indicator to infer changes in the dynamics of populations under stress. © 2017 The Author(s).

  1. Remotely Sensing Larval Population Dynamics of Rice Field Anophelines

    Science.gov (United States)

    Beck, Louisa R.; Dister, Sheri W.; Wood, Byron L.; Washino, Robert K.

    1997-01-01

    The primary objective of both studies was to determine if RS and GIS techniques could be used to distinguish between high and low larval-producing rice fields in California. Results of the first study suggested that early-season green-up and proximity to livestock pastures were positively correlated with high larval abundance. Based on the early-season spectral differences between high and low larval-producing fields, it appeared that canopy development and tillering influenced mosquito habitat quality. At that time, rice fields consisted of a mixture of plants and water, a combination that allowed An. freeborni females to lay eggs in partial sunlight, protected from both predators and wind. This established a population earlier in the season than in other, 'less-green' fields where tillering and plant emergence was too minimal for ovipositioning. The study also indicated the importance of the distance that a mosquito would have to fly in order to take a bloodmeal prior to ovipositing. These associations were fully explored in an expanded study two years later. The second study confirmed the positive relationship between early season canopy development and larval abundance, and also demonstrated the relationship between abundance and distance-to-pasture. The association between greenness (as measured using NDVI), distance-to-pasture, and abundance is illustrated. The second study also indicated the siginificance of the landscape context of rice fields for larval production. Fields that included opportunities for feeding and resting within the flight range of the mosquito had higher abundances than did fields that were in a homogeneous rice area.

  2. Mesola red deer: physical characteristics, population dynamics and conservation perspectives

    Directory of Open Access Journals (Sweden)

    Stefano Mattioli

    2003-10-01

    Full Text Available Abstract The biometry, demography and genetics of red deer Cervus elaphus of Mesola Wood (NE Italy, are presented and discussed in relation to the conservation of this population. Modest body size, low stature, oversimplified antlers and a low reproductive performance characterise red deer from Mesola Wood. The mitochondrial genome showed a private haplotype, different from other red deer in Italy and central Europe. The uniqueness of this nucleus and its biogeographic importance make a long-term conservation plan particularly urgent. Management measures such as fallow deer reduction, winter feeding and pasture mowing were tested, giving promising results. The physical condition of the animals improved, calf and adult mortality declined, and a few cases of antlers with bez tine or crown were reported in this study after four decades. Riassunto Il Cervo della Mesola: caratteristiche fisiche, dinamica di popolazione e prospettive di conservazione La biometria, la demografia e la genetica del cervo Cervus elaphus del Gran Bosco della Mesola (Italia nord-orientale, vengono presentate e discusse in relazione alla salvaguardia di questa popolazione. Il cervo della Mesola risulta caratterizzato dalle modeste dimensioni corporee, dalla struttura semplificata dei palchi e da un basso rendimento riproduttivo. L'analisi del genoma mitocondriale ha evidenziato un aplotipo privato, diverso da quello degli altri cervi italiani e centroeuropei. L'unicità di questo nucleo e la sua importanza biogeografica rendono particolarmente urgente un piano di conservazione a lungo termine. Sono stati verificati interventi gestionali quali la riduzione numerica dei daini, il foraggiamento invernale e lo sfalcio delle superfici a pascolo, con risultati promettenti. Le condizioni fisiche degli animali sono migliorate, la mortalità tra i piccoli e gli adulti è diminuita, e sono stati registrati alcuni

  3. Population dynamics of Greater Scaup breeding on the Yukon-Kuskokwim Delta, Alaska

    Science.gov (United States)

    Flint, Paul L.; Grand, J. Barry; Fondell, Thomas F.; Morse, Julie A.

    2006-01-01

    Populations of greater scaup (Aythya marila) remained relatively stable during a period when populations of lesser scaup (A. affinis) have declined from historic levels. To assist in describing these differences in population trends, from 1991 through 2000, we studied the survival, nesting ecology, and productivity of greater scaup on the Yukon-Kuskokwim Delta (Y-K Delta), Alaska, to develop a model of population dynamics. We located nests, radio-marked females for renesting studies, estimated duckling survival, and leg-banded females to examine nest site fidelity and annual survival.

  4. 'Wildlife 2001: Populations', an International Conference on Population Dynamics and Management of Vertebrates

    CERN Document Server

    Barrett, Reginald

    1992-01-01

    In 1984, a conference called Wildlife 2000: Modeling habitat relationships of terrestrial vertebrates, was held at Stanford Sierra Camp at Fallen Leaf Lake in the Sierra Nevada Mountains of California. The conference was well-received, and the published volume (Verner, J. , M. L. Morrison, and C. J. Ralph, editors. 1986. Wildlife 2000: modeling habitat relationships of terrestrial vertebrates, University of Wisconsin Press, Madison, Wisconsin, USA) proved to be a landmark publication that received a book award by The Wildlife Society. Wildlife 2001: populations was a followup conference with emphasis on the other major biological field of wildlife conservation and management, populations. It was held on July 29-31, 1991, at the Oakland Airport Hilton Hotel in Oakland, California, in accordance with our intent that this conference have a much stronger international representation than did Wildlife 2000. The goal of the conference was to bring together an international group of specialists to address the state ...

  5. Predation, Competition, and Abiotic Disturbance: Population Dynamics of Small Mammals

    Energy Technology Data Exchange (ETDEWEB)

    Yunger, John A. [Northern Illinois U.

    1996-01-01

    Predation and food availability have been implicated in annual non-cyclic fluctuations of vertebrate prey at mid-latitudes. The timing and magnitude of these factors are unclear due to a lack of large-scale field experiments, little attention to interactions, and a failure to closely link vertebrate predators with their prey. From October 1992 to January 1996, small mammal populations were censused on eight 0.6 ha plots at monthly intervals in a 32-ha prairie restoration at Fermi National Accelerator Laboratory, Illinois. Terrestrial vertebrate predators were excluded after July 1993 from four of the eight plots and canid diets monitored. Both terrestrial and avian vertebrate predators were excluded in March 1994. During 1993 small mammal densities (i.e., Microtus pennsylvanicus, Peromyscus leucopus, and P. maniculatus) were relatively high. Following peak densities in late summer, Microtus numbers were 2-3x greater on exclusion plots relative to controls due to preferential selection of Microtus by canids, as reflected in diets. Following an ice-storm and crash in small mammal numbers (particularly Microtus), vertebrate predator exclusion had no detectable effect on P. leucopus numbers, probably due to an abundance of alternative prey (i.e., Sylvilagus floridanus). Meadow vole numbers began to increase in Fall 1995, and a numerical effect of predator exclusion, similar to that in 1993, was observed. Predator exclusion had no detectable effect on the movements and spatial patterns of Microtus during 1993. There was a significant decrease in home range and a significant increase in home range overlap for £.. leucopus on the predator exclusion plots. The change in spatial behavior may be due to interspecific competition with Microtus resulting from increased densities on exclusion plots. Thus, predators had an indirect effect on .f.. leucopus spatial patterns mediated through M. pennsylvanicus. The role of food limitation was studied using natural and manipulative

  6. Predation, Competition, and Abiotic Disturbance: Population Dynamics of Small Mammals

    Energy Technology Data Exchange (ETDEWEB)

    Yunger, John A.; /Northern Illinois U. /Northern Illinois U.

    1996-01-01

    Predation and food availability have been implicated in annual non-cyclic fluctuations of vertebrate prey at mid-latitudes. The timing and magnitude of these factors are unclear due to a lack of large-scale field experiments, little attention to interactions, and a failure to closely link vertebrate predators with their prey. From October 1992 to January 1996, small mammal populations were censused on eight 0.6 ha plots at monthly intervals in a 32-ha prairie restoration at Fermi National Accelerator Laboratory, Illinois. Terrestrial vertebrate predators were excluded after July 1993 from four of the eight plots and canid diets monitored. Both terrestrial and avian vertebrate predators were excluded in March 1994. During 1993 small mammal densities (i.e., Microtus Pennsylvanicus, Peromyscus leucopus, and P. maniculatus) were relatively high. Following peak densities in late summer, Microtus numbers wer 2-3x greater on exclusion plots relative to controls due to preferential selection of Microtus by canids, as reflected in dits. Following an ice-storm and crash in small mammal numbers (particularly Microtus), vertebrate predator exclusion had no detectable effect on P. leucopus numbers, probably due to an abundance of alternative prey (i.e., Sylvilagus floridanus). Meadow vole numbers began to increase in Fall 1995, and a numerical effect of predator exclusion, similar to that in 1993, was observed. Predator exclusion had no detectable effect on the movements and spatial patterns of Microtus during 1993. There was a significant decrease in home range and a significant increase in home range overlap for P. leucopus on the predator exclusion plots. The change in spatial behavior may be due to interspecific competition with Microtus resulting from increased densities on exclusion plots. Thus, predators had an indirect effect on P. leucopus spatial patterns mediated through M. Pennsylvanicus. The role of food limitation was studied using natural and manipulative

  7. Nutritional quality of foods marketed to children in Honduras.

    Science.gov (United States)

    Gunderson, Matthew D; Clements, Dennis; Benjamin Neelon, Sara E

    2014-02-01

    Evidence suggests that exposure to advertising of unhealthy foods may contribute to increased rates of obesity in children. This study examined the extent to which television stations marketed unhealthy foods to children during after-school programming aired over one week in La Ceiba, Honduras. Content analysis was performed on four television stations, including one broadcast station and three cable networks. Eighty hours of programming were recorded and analyzed. Advertised products were categorized as food or non-food items, with food items further classified as healthy or unhealthy. Advertisements were coded as those aimed at children, adults, or both, and chi-square tests were used to compare the proportion of unhealthy advertisements by target audience. A total of 2271 advertisements aired during the observation period, with 1120 marketing products (49.3%). Of those, 397 (35.4%) promoted foods-30.2% were for healthy foods and 69.8% for unhealthy foods. The unhealthy foods were all advertised on cable networks and not the broadcast station. Children appeared to be targeted more than adults in advertisements for unhealthy foods (92.1%, p<0.001). Cable television programming during after-school hours advertised primarily unhealthy foods. Exposure to these advertisements may promote consumption of unhealthy foods by children, increasing their risk of obesity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Comic books carry health messages to rural children in Honduras.

    Science.gov (United States)

    Vigano, O

    1983-12-01

    This article reports on the use of children as message carriers in a rural water and sanitation project in western Honduras. The Honduran Water and Sanitation Project represents the 1st such effort to have a specific health education component. It was decided to direct the education component toward children because of their important role in providing and handling drinking water and caring for younger members of the family. Rural primary schools surfaced as a potential channel of communication. The comic book format was selected because it is simple enough to be used in the schools without much training, economical to produce (US$0.30/copy), effective and attractive to children, and consistent with the Project's philosophy that dialogue and participation are essential components of health education. Each comic book contains a single-concept message, e.g., 1 cause of water contamination or a method of water purification. The 1st module was pretested in 3 rural schools. Following classroom study of the comic book, correct answers on 5 questions related to the comic book story increased from 59% to 80%. 95% of the children indicated that they liked the characters, and teachers expressed satisfaction with the materials. 1200 copies of the 1st module have been distributed to 30 rural schools, and production plans include 11 additional modules on topics such as prevention of water-related sickness and personal hygiene.

  9. In-hospital pediatric cardiac arrest in Honduras.

    Science.gov (United States)

    Matamoros, Martha; Rodriguez, Roger; Callejas, Allison; Carranza, Douglas; Zeron, Hilda; Sánchez, Carlos; Del Castillo, Jimena; López-Herce, Jesús

    2015-01-01

    The objective of this study was to analyze the characteristic and the prognostic factors of in-hospital pediatric cardiac arrest (CA) in a public hospital Honduras. A prospective observational study was performed on pediatric in-hospital CA as a part of a multicenter international study. One hundred forty-six children were studied. The primary end point was survival at hospital discharge. Univariate and multivariate logistic regression analyses were performed to assess the influence of each factor on mortality. Cardiac arrest occurred in the emergency department in 66.9%. Respiratory diseases and sepsis were predominant causes of CA. Return of spontaneous circulation was achieved in 60% of patients, and 22.6% survived to hospital discharge. The factors related with mortality were nonrespiratory cause of CA (odds ratio [OR], 2.55; P = 0.045), adrenaline administration (OR, 4.96; P = 0.008), and a duration of cardiopulmonary resuscitation more than 10 minutes (OR, 3.40; P = 0.012). In-hospital CA in children in a developing country has low survival. Patients with nonrespiratory causes and those who need adrenaline administration and prolonged resuscitation had worse prognosis.

  10. Leprosy Associated with Atypical Cutaneous Leishmaniasis in Nicaragua and Honduras.

    Science.gov (United States)

    Soto, Lucrecia Acosta; Caballero, Nelson; Fuentes, Lesny Ruth; Muñoz, Pedro Torres; Gómez Echevarría, Jose Ramón; López, Montserrat Pérez; Bornay Llinares, Fernando Jorge; Stanford, John L; Stanford, Cynthia A; Donoghue, Helen D

    2017-10-01

    In Central America, few cases of leprosy have been reported, but the disease may be unrecognized. Diagnosis is based on clinical criteria and histology. Preliminary field work in Nicaragua and Honduras found patients, including many children, with skin lesions clinically suggestive of atypical cutaneous leishmaniasis or indeterminate leprosy. Histology could not distinguish these diseases although acid-fast organisms were visible in a few biopsies. Lesions healed after standard antimicrobial therapy for leprosy. In the present study, patients, family members, and other community members were skin-tested and provided nasal swabs and blood samples. Biopsies were taken from a subgroup of patients with clinical signs of infection. Two laboratories analyzed samples, using local in-house techniques. Mycobacterium leprae , Leishmania spp. and Leishmania infantum were detected using polymerase chain reactions. Mycobacterium leprae DNA was detected in blood samples and nasal swabs, including some cases where leprosy was not clinically suspected. Leishmania spp. were also detected in blood and nasal swabs. Most biopsies contained Leishmania DNA and coinfection of Leishmania spp. with M. leprae occurred in 33% of cases. Mycobacterium leprae DNA was also detected and sequenced from Nicaraguan and Honduran environmental samples. In conclusion, leprosy and leishmaniasis are present in both regions, and leprosy appears to be widespread. The nature of any relationship between these two pathogens and the epidemiology of these infections need to be elucidated.

  11. Maternal Support for Human Papillomavirus Vaccination in Honduras

    Science.gov (United States)

    Langrish, Sarah M.; Cotton, Deborah J.; Simon, Carol J.

    2011-01-01

    Abstract Background Cervical cancer is a leading cause of cancer death for women in Latin America, and vaccinating against human papillomavirus (HPV) has the potential to limit this disease. We sought to determine Honduran women's awareness of HPV vaccination and interest in vaccinating their daughters against HPV. Methods We interviewed mothers aged ≥17 at primary care clinics in Honduras. First, we collected demographic information and assessed knowledge related to cervical cancer prevention and awareness of HPV and HPV vaccination. Because most participants were not familiar with HPV, education about the relationships among HPV, sexual activity, and cervical cancer was provided before we asked participants if they would accept HPV vaccination for a 9-year-old daughter. We used multivariable logistic regression to determine predictors of vaccine acceptance. Results We interviewed 632 mothers. Only 13% had heard of HPV vaccination before the interview. After education, 91% would accept HPV vaccination for a 9-year-old daughter. Mothers who intended to vaccinate knew more at baseline about cervical cancer prevention than did those who did not endorse vaccination. Demographic characteristics did not predict vaccine acceptance. Conclusions Few Honduran mothers were aware of HPV or HPV vaccination. However, most Honduran mothers would accept HPV vaccination for their daughters after receiving education about the relationship between HPV infection and cervical cancer. Baseline cervical cancer knowledge was associated with vaccine acceptance. PMID:21091226

  12. Boom or bust? A comparative analysis of transient population dynamics in plants

    DEFF Research Database (Denmark)

    Stott, Iain; Franco, Miguel; Carslake, David

    2010-01-01

    researchers as further possible effectors of complicated dynamics. Previously published methods of transient analysis have tended to require knowledge of initial population structure. However, this has been overcome by the recent development of the parametric Kreiss bound (which describes how large...... a population must become before reaching its maximum possible transient amplification following a disturbance) and the extension of this and other transient indices to simultaneously describe both amplified and attenuated transient dynamics. We apply the Kreiss bound and other transient indices to a data base...... worrying artefact of basic model parameterization. Synthesis. Transient indices describe how big or how small plant populations can get, en route to long-term stable rates of increase or decline. The patterns we found in the potential for transient dynamics, across many species of plants, suggest...

  13. Using dynamic stochastic modelling to estimate population risk factors in infectious disease: the example of FIV in 15 cat populations.

    Directory of Open Access Journals (Sweden)

    David Fouchet

    Full Text Available BACKGROUND: In natural cat populations, Feline Immunodeficiency Virus (FIV is transmitted through bites between individuals. Factors such as the density of cats within the population or the sex-ratio can have potentially strong effects on the frequency of fight between individuals and hence appear as important population risk factors for FIV. METHODOLOGY/PRINCIPAL FINDINGS: To study such population risk factors, we present data on FIV prevalence in 15 cat populations in northeastern France. We investigate five key social factors of cat populations; the density of cats, the sex-ratio, the number of males and the mean age of males and females within the population. We overcome the problem of dependence in the infective status data using sexually-structured dynamic stochastic models. Only the age of males and females had an effect (p = 0.043 and p = 0.02, respectively on the male-to-female transmission rate. Due to multiple tests, it is even likely that these effects are, in reality, not significant. Finally we show that, in our study area, the data can be explained by a very simple model that does not invoke any risk factor. CONCLUSION: Our conclusion is that, in host-parasite systems in general, fluctuations due to stochasticity in the transmission process are naturally very large and may alone explain a larger part of the variability in observed disease prevalence between populations than previously expected. Finally, we determined confidence intervals for the simple model parameters that can be used to further aid in management of the disease.

  14. Prediction of population with Alzheimer's disease in the European Union using a system dynamics model.

    Science.gov (United States)

    Tomaskova, Hana; Kuhnova, Jitka; Cimler, Richard; Dolezal, Ondrej; Kuca, Kamil

    2016-01-01

    Alzheimer's disease (AD) is a slowly progressing neurodegenerative brain disease with irreversible brain effects; it is the most common cause of dementia. With increasing age, the probability of suffering from AD increases. In this research, population growth of the European Union (EU) until the year 2080 and the number of patients with AD are modeled. The aim of this research is to predict the spread of AD in the EU population until year 2080 using a computer simulation. For the simulation of the EU population and the occurrence of AD in this population, a system dynamics modeling approach has been used. System dynamics is a useful and effective method for the investigation of complex social systems. Over the past decades, its applicability has been demonstrated in a wide variety of applications. In this research, this method has been used to investigate the growth of the EU population and predict the number of patients with AD. The model has been calibrated on the population prediction data created by Eurostat. Based on data from Eurostat, the EU population until year 2080 has been modeled. In 2013, the population of the EU was 508 million and the number of patients with AD was 7.5 million. Based on the prediction, in 2040, the population of the EU will be 524 million and the number of patients with AD will be 13.1 million. By the year 2080, the EU population will be 520 million and the number of patients with AD will be 13.7 million. System dynamics modeling approach has been used for the prediction of the number of patients with AD in the EU population till the year 2080. These results can be used to determine the economic burden of the treatment of these patients. With different input data, the simulation can be used also for the different regions as well as for different noncontagious disease predictions.

  15. The cultural implications of growth: Modeling nonlinear interaction of trait selection and population dynamics

    Science.gov (United States)

    Antoci, Angelo; Galeotti, Marcello; Russu, Paolo; Luigi Sacco, Pier

    2018-05-01

    In this paper, we study a nonlinear model of the interaction between trait selection and population dynamics, building on previous work of Ghirlanda et al. [Theor. Popul. Biol. 77, 181-188 (2010)] and Antoci et al. [Commun. Nonlinear Sci. Numer. Simul. 58, 92-106 (2018)]. We establish some basic properties of the model dynamics and present some simulations of the fine-grained structure of alternative dynamic regimes for chosen combinations of parameters. The role of the parameters that govern the reinforcement/corruption of maladaptive vs. adaptive traits is of special importance in determining the model's dynamic evolution. The main implication of this result is the need to pay special attention to the structural forces that may favor the emergence and consolidation of maladaptive traits in contemporary socio-economies, as it is the case, for example, for the stimulation of dysfunctional consumption habits and lifestyles in the pursuit of short-term profits.

  16. Dynamics of weakly inhomogeneous oscillator populations: perturbation theory on top of Watanabe-Strogatz integrability

    Science.gov (United States)

    Vlasov, Vladimir; Rosenblum, Michael; Pikovsky, Arkady

    2016-08-01

    As has been shown by Watanabe and Strogatz (WS) (1993 Phys. Rev. Lett. 70 2391), a population of identical phase oscillators, sine-coupled to a common field, is a partially integrable system: for any ensemble size its dynamics reduce to equations for three collective variables. Here we develop a perturbation approach for weakly nonidentical ensembles. We calculate corrections to the WS dynamics for two types of perturbations: those due to a distribution of natural frequencies and of forcing terms, and those due to small white noise. We demonstrate that in both cases, the complex mean field for which the dynamical equations are written is close to the Kuramoto order parameter, up to the leading order in the perturbation. This supports the validity of the dynamical reduction suggested by Ott and Antonsen (2008 Chaos 18 037113) for weakly inhomogeneous populations.

  17. Dynamics of weakly inhomogeneous oscillator populations: perturbation theory on top of Watanabe–Strogatz integrability

    International Nuclear Information System (INIS)

    Vlasov, Vladimir; Rosenblum, Michael; Pikovsky, Arkady

    2016-01-01

    As has been shown by Watanabe and Strogatz (WS) (1993 Phys. Rev. Lett. 70 2391), a population of identical phase oscillators, sine-coupled to a common field, is a partially integrable system: for any ensemble size its dynamics reduce to equations for three collective variables. Here we develop a perturbation approach for weakly nonidentical ensembles. We calculate corrections to the WS dynamics for two types of perturbations: those due to a distribution of natural frequencies and of forcing terms, and those due to small white noise. We demonstrate that in both cases, the complex mean field for which the dynamical equations are written is close to the Kuramoto order parameter, up to the leading order in the perturbation. This supports the validity of the dynamical reduction suggested by Ott and Antonsen (2008 Chaos 18 037113) for weakly inhomogeneous populations. (letter)

  18. The cultural implications of growth: Modeling nonlinear interaction of trait selection and population dynamics.

    Science.gov (United States)

    Antoci, Angelo; Galeotti, Marcello; Russu, Paolo; Luigi Sacco, Pier

    2018-05-01

    In this paper, we study a nonlinear model of the interaction between trait selection and population dynamics, building on previous work of Ghirlanda et al. [Theor. Popul. Biol. 77, 181-188 (2010)] and Antoci et al. [Commun. Nonlinear Sci. Numer. Simul. 58, 92-106 (2018)]. We establish some basic properties of the model dynamics and present some simulations of the fine-grained structure of alternative dynamic regimes for chosen combinations of parameters. The role of the parameters that govern the reinforcement/corruption of maladaptive vs. adaptive traits is of special importance in determining the model's dynamic evolution. The main implication of this result is the need to pay special attention to the structural forces that may favor the emergence and consolidation of maladaptive traits in contemporary socio-economies, as it is the case, for example, for the stimulation of dysfunctional consumption habits and lifestyles in the pursuit of short-term profits.

  19. Studies on the population dynamics of a rumor-spreading model in online social networks

    Science.gov (United States)

    Dong, Suyalatu; Fan, Feng-Hua; Huang, Yong-Chang

    2018-02-01

    This paper sets up a rumor spreading model in online social networks based on the European fox rabies SIR model. The model considers the impact of changing number of online social network users, combines the transmission dynamics to set up a population dynamics of rumor spreading model in online social networks. Simulation is carried out on online social network, and results show that the new rumor spreading model is in accordance with the real propagation characteristics in online social networks.

  20. Efficacy of chloroquine for the treatment of uncomplicated Plasmodium falciparum malaria in Honduras.

    Science.gov (United States)

    Mejia Torres, Rosa Elena; Banegas, Engels Ilich; Mendoza, Meisy; Diaz, Cesar; Bucheli, Sandra Tamara Mancero; Fontecha, Gustavo A; Alam, Md Tauqeer; Goldman, Ira; Udhayakumar, Venkatachalam; Zambrano, Jose Orlinder Nicolas

    2013-05-01

    Chloroquine (CQ) is officially used for the primary treatment of Plasmodium falciparum malaria in Honduras. In this study, the therapeutic efficacy of CQ for the treatment of uncomplicated P. falciparum malaria in the municipality of Puerto Lempira, Gracias a Dios, Honduras was evaluated using the Pan American Health Organization-World Health Organization protocol with a follow-up of 28 days. Sixty-eight patients from 6 months to 60 years of age microscopically diagnosed with uncomplicated P. falciparum malaria were included in the final analysis. All patients who were treated with CQ (25 mg/kg over 3 days) cleared parasitemia by day 3 and acquired no new P. falciparum infection within 28 days of follow-up. All the parasite samples sequenced for CQ resistance mutations (pfcrt) showed only the CQ-sensitive genotype (CVMNK). This finding shows that CQ remains highly efficacious for the treatment of uncomplicated P. falciparum malaria in Gracias a Dios, Honduras.

  1. Determinants of Health Service Responsiveness in Community-Based Vector Surveillance for Chagas Disease in Guatemala, El Salvador, and Honduras

    Science.gov (United States)

    Hashimoto, Ken; Zúniga, Concepción; Romero, Eduardo; Morales, Zoraida; Maguire, James H.

    2015-01-01

    Background Central American countries face a major challenge in the control of Triatoma dimidiata, a widespread vector of Chagas disease that cannot be eliminated. The key to maintaining the risk of transmission of Trypanosoma cruzi at lowest levels is to sustain surveillance throughout endemic areas. Guatemala, El Salvador, and Honduras integrated community-based vector surveillance into local health systems. Community participation was effective in detection of the vector, but some health services had difficulty sustaining their response to reports of vectors from the population. To date, no research has investigated how best to maintain and reinforce health service responsiveness, especially in resource-limited settings. Methodology/Principal Findings We reviewed surveillance and response records of 12 health centers in Guatemala, El Salvador, and Honduras from 2008 to 2012 and analyzed the data in relation to the volume of reports of vector infestation, local geography, demography, human resources, managerial approach, and results of interviews with health workers. Health service responsiveness was defined as the percentage of households that reported vector infestation for which the local health service provided indoor residual spraying of insecticide or educational advice. Eight potential determinants of responsiveness were evaluated by linear and mixed-effects multi-linear regression. Health service responsiveness (overall 77.4%) was significantly associated with quarterly monitoring by departmental health offices. Other potential determinants of responsiveness were not found to be significant, partly because of short- and long-term strategies, such as temporary adjustments in manpower and redistribution of tasks among local participants in the effort. Conclusions/Significance Consistent monitoring within the local health system contributes to sustainability of health service responsiveness in community-based vector surveillance of Chagas disease. Even with

  2. Determinants of Health Service Responsiveness in Community-Based Vector Surveillance for Chagas Disease in Guatemala, El Salvador, and Honduras.

    Science.gov (United States)

    Hashimoto, Ken; Zúniga, Concepción; Romero, Eduardo; Morales, Zoraida; Maguire, James H

    2015-01-01

    Central American countries face a major challenge in the control of Triatoma dimidiata, a widespread vector of Chagas disease that cannot be eliminated. The key to maintaining the risk of transmission of Trypanosoma cruzi at lowest levels is to sustain surveillance throughout endemic areas. Guatemala, El Salvador, and Honduras integrated community-based vector surveillance into local health systems. Community participation was effective in detection of the vector, but some health services had difficulty sustaining their response to reports of vectors from the population. To date, no research has investigated how best to maintain and reinforce health service responsiveness, especially in resource-limited settings. We reviewed surveillance and response records of 12 health centers in Guatemala, El Salvador, and Honduras from 2008 to 2012 and analyzed the data in relation to the volume of reports of vector infestation, local geography, demography, human resources, managerial approach, and results of interviews with health workers. Health service responsiveness was defined as the percentage of households that reported vector infestation for which the local health service provided indoor residual spraying of insecticide or educational advice. Eight potential determinants of responsiveness were evaluated by linear and mixed-effects multi-linear regression. Health service responsiveness (overall 77.4%) was significantly associated with quarterly monitoring by departmental health offices. Other potential determinants of responsiveness were not found to be significant, partly because of short- and long-term strategies, such as temporary adjustments in manpower and redistribution of tasks among local participants in the effort. Consistent monitoring within the local health system contributes to sustainability of health service responsiveness in community-based vector surveillance of Chagas disease. Even with limited resources, countries can improve health service

  3. Generalization of the Rabi population inversion dynamics in the sub-one-cycle pulse limit

    International Nuclear Information System (INIS)

    Doslic, N.

    2006-01-01

    We consider the population inversion in a two-level system generated by a sub-one-cycle pulse excitation. Specifically, we explore the effect that the time derivative of the pulse envelope has on the Rabi dynamics. Our analysis is based on a combination of analytical, perturbative, and nonperturbative treatments and is complemented by numerical simulations. We find a shortening of the Rabi inversion period and show that complete inversion is unobtainable under resonant, ultrashort pulse conditions. The impact of nonresonant and carrier-envelope phase-dependent effects on the dynamics of two-level and multilevel systems is studied numerically, and conditions for complete population inversion are derived

  4. Metastable states and quasicycles in a stochastic Wilson-Cowan model of neuronal population dynamics

    KAUST Repository

    Bressloff, Paul C.

    2010-11-03

    We analyze a stochastic model of neuronal population dynamics with intrinsic noise. In the thermodynamic limit N→∞, where N determines the size of each population, the dynamics is described by deterministic Wilson-Cowan equations. On the other hand, for finite N the dynamics is described by a master equation that determines the probability of spiking activity within each population. We first consider a single excitatory population that exhibits bistability in the deterministic limit. The steady-state probability distribution of the stochastic network has maxima at points corresponding to the stable fixed points of the deterministic network; the relative weighting of the two maxima depends on the system size. For large but finite N, we calculate the exponentially small rate of noise-induced transitions between the resulting metastable states using a Wentzel-Kramers- Brillouin (WKB) approximation and matched asymptotic expansions. We then consider a two-population excitatory or inhibitory network that supports limit cycle oscillations. Using a diffusion approximation, we reduce the dynamics to a neural Langevin equation, and show how the intrinsic noise amplifies subthreshold oscillations (quasicycles). © 2010 The American Physical Society.

  5. The demography of climate-driven and density-regulated population dynamics in a perennial plant

    DEFF Research Database (Denmark)

    Dahlgren, Johan; Bengstsson, Karin; Ehrlén, Johan

    2016-01-01

    Identifying the internal and external drivers of population dynamics is a key objective in ecology, currently accentuated by the need to forecast the effects of climate change on species distributions and abundances. The interplay between environmental and density effects is one particularly...... important aspect of such forecasts. We examined the simultaneous impact of climate and intraspecific density on vital rates of the dwarf shrub Fumana procumbens over 20 yr, using generalized additive mixed models. We then analyzed effects on population dynamics using integral projection models...... to be driven solely by the environment can overestimate extinction risks if there is density dependence. We conclude that density regulation can dampen effects of climate change on Fumana population size, and discuss the need to quantify density dependence in predictions of population responses...

  6. Collective dynamics of populations of weakly correlated filaments of incoherent white light

    International Nuclear Information System (INIS)

    Guo, Jinxin; Sheridan, John T; Saravanamuttu, Kalaichelvi

    2013-01-01

    We examined the dynamics of two populations of self-trapped filaments of spatially and temporally incoherent white light. The populations consisted of (i) independent filaments generated through self-trapping of incandescent speckles, and (ii) co-dependent filaments created through modulation instability of a broad incandescent beam. Both filament populations were positionally stable in conditions where individual pairs of self-trapped beams interact strongly. Both also acquired significantly broad intensity distributions, which were independent of their parent optical fields; a small but persistent number of high-intensity filaments was identified in both cases. These studies provide accessible routes to weakly correlated ensembles, insight into their collective behaviour such as self-stabilization and self-selected intensity distributions, and reveal intriguing similarities between the dynamics of two populations of different origins. (paper)

  7. Disentangling the effects of climate, density dependence, and harvest on an iconic large herbivore's population dynamics

    DEFF Research Database (Denmark)

    Koons, David; Colchero, Fernando; Hersey, Kent

    2015-01-01

    Understanding the relative effects of climate, harvest, and density dependence on population dynamics is critical for guiding sound population management, especially for ungulates in arid and semi-arid environments experiencing climate change. To address these issues for bison in southern Utah, we...... than precipitation and other temperature-related variables (model weight > 3 times more than that for other climate variables). Although we hypothesized that harvest is the primary driving force of bison population dynamics in southern Utah, our elasticity analysis indicated that changes in early...... spring temperature could have a greater ‘relative effect’ on equilibrium abundance than either harvest or the strength of density dependence. Our findings highlight the utility of incorporating elasticity analyses into state-space population models, and the need to include climatic processes in wildlife...

  8. Ongoing removals of invasive lionfish in Honduras and their effect on native Caribbean prey fishes.

    Science.gov (United States)

    Peiffer, Friederike; Bejarano, Sonia; Palavicini de Witte, Giacomo; Wild, Christian

    2017-01-01

    The invasion of Indo-Pacific lionfish is one of the most pressing concerns in the context of coral reef conservation throughout the Caribbean. Invasive lionfish threaten Caribbean fish communities by feeding on a wide range of native prey species, some of which have high ecological and economic value. In Roatan (Honduras) a local non-governmental organisation (i.e. Roatan Marine Park) trains residents and tourists in the use of spears to remove invasive lionfish. Here, we assess the effectiveness of local removal efforts in reducing lionfish populations. We ask whether reefs subject to relatively frequent removals support more diverse and abundant native fish assemblages compared to sites were no removals take place. Lionfish biomass, as well as density and diversity of native prey species were quantified on reefs subject to regular and no removal efforts. Reefs subject to regular lionfish removals (two to three removals month -1 ) with a mean catch per unit effort of 2.76 ± 1.72 lionfish fisher -1 h -1 had 95% lower lionfish biomass compared to non-removal sites. Sites subject to lionfish removals supported 30% higher densities of native prey-sized fishes compared to sites subject to no removal efforts. We found no evidence that species richness and diversity of native fish communities differ between removal and non-removal sites. We conclude that opportunistic voluntary removals are an effective management intervention to reduce lionfish populations locally and might alleviate negative impacts of lionfish predation. We recommend that local management and the diving industry cooperate to cost-effectively extend the spatial scale at which removal regimes are currently sustained.

  9. Ongoing removals of invasive lionfish in Honduras and their effect on native Caribbean prey fishes

    Directory of Open Access Journals (Sweden)

    Friederike Peiffer

    2017-10-01

    Full Text Available The invasion of Indo-Pacific lionfish is one of the most pressing concerns in the context of coral reef conservation throughout the Caribbean. Invasive lionfish threaten Caribbean fish communities by feeding on a wide range of native prey species, some of which have high ecological and economic value. In Roatan (Honduras a local non-governmental organisation (i.e. Roatan Marine Park trains residents and tourists in the use of spears to remove invasive lionfish. Here, we assess the effectiveness of local removal efforts in reducing lionfish populations. We ask whether reefs subject to relatively frequent removals support more diverse and abundant native fish assemblages compared to sites were no removals take place. Lionfish biomass, as well as density and diversity of native prey species were quantified on reefs subject to regular and no removal efforts. Reefs subject to regular lionfish removals (two to three removals month−1 with a mean catch per unit effort of 2.76 ± 1.72 lionfish fisher−1 h−1 had 95% lower lionfish biomass compared to non-removal sites. Sites subject to lionfish removals supported 30% higher densities of native prey-sized fishes compared to sites subject to no removal efforts. We found no evidence that species richness and diversity of native fish communities differ between removal and non-removal sites. We conclude that opportunistic voluntary removals are an effective management intervention to reduce lionfish populations locally and might alleviate negative impacts of lionfish predation. We recommend that local management and the diving industry cooperate to cost-effectively extend the spatial scale at which removal regimes are currently sustained.

  10. Life history and spatial determinants of somatic growth dynamics in Komodo dragon populations

    OpenAIRE

    Laver, Rj; Purwandana, D; Ariefiandy, A; Imansyah, J; Forsyth, D; Ciofi, C; Jessop, Ts

    2012-01-01

    Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture st...

  11. A model of population dynamics of TB in a prison system and application to South Africa

    OpenAIRE

    Witbooi, Peter; Vyambwera, Sibaliwe Maku

    2017-01-01

    Background Tuberculosis (TB) continues to spread in South African prisons in particular, as prisons are over-capacitated and have poor ventilation. The awaiting trial detainees are not screened on admission and are at high risk of getting infected with TB. Results We propose a compartmental model to describe the population dynamics of TB disease in prisons. Our model considers the inflow of susceptible, exposed and TB infectives into the prison population. Removal of individuals out of the pr...

  12. Nonlinearities Lead to Qualitative Differences in Population Dynamics of Predator-Prey Systems

    Czech Academy of Sciences Publication Activity Database

    Ameixa, Olga; Messelink, G. J.; Kindlmann, Pavel

    2013-01-01

    Roč. 8, č. 4 (2013), e62530-e62530 E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA ČR(CZ) GEVOL/11/E036 Institutional support: RVO:67179843 Keywords : nonlinear system * population density * population dynamics * predator * predator prey interaction * qualitative analysis Subject RIV: EH - Ecology, Behaviour Impact factor: 3.534, year: 2013

  13. Endogenous Population Dynamics and Economic Growth with Free Trade between Countries

    OpenAIRE

    Wei-Bin Zhang

    2016-01-01

    This paper builds a model to deal with dynamic interdependence between different countries' birth rates, mortality rates, populations, wealth accumulation, and time distributions between working, leisure and children caring. The model shows the role of human capital, technological and preference changes on national differences in birth rates, mortality rates, time distributions, population change, and wealth accumulation. The economic mechanisms of wealth accumulation, production and trade ar...

  14. Report on Honduras: ripples in the pond--the financial crisis and remittances to chronically ill patients in Honduras.

    Science.gov (United States)

    Piette, John D; Mendoza-Avelares, Milton O; Chess, Laura; Milton, Evan C; Matiz Reyes, Armando; Rodriguez-Saldaña, Joel

    2012-01-01

    The U.S. financial crisis has affected employment opportunities for Latino immigrants, and this could affect their ability to send financial assistance, or "remittances", to chronically ill family members in their home country. In a cross-sectional survey of 624 chronically ill adults conducted in Honduras between June and August 2009, respondents reported their receipt of remittances, health service use, and cost-related access barriers. Fifty-four percent of respondents reported relatives living outside the country, and of this group, 66 percent (37% of the overall sample) received remittances. Seventy-four percent of respondents receiving remittances reported a decrease over the prior year, mostly due to job losses among their relatives abroad. Respondents reporting reductions in remittances received significantly less per month, on average, than those without a reduction (US $170 vs. $234; p = 0.01). In multivariate models, respondents experiencing a reduction in remittances used fewer health services and medications due to cost concerns. Remittance payments from relatives resident in the United States are a major source of income for chronically ill individuals in Latin America. Most recipients of remittances reported a reduction during the financial downturn that affected their access to care.

  15. Increased prevalence of Plasmodium falciparum malaria in Honduras, Central America Aumento de la prevalencia de malaria por Plasmodium falciparum en Honduras, Centroamerica

    Directory of Open Access Journals (Sweden)

    Carol J. Palmer

    1998-07-01

    Full Text Available We report on our investigation of a malaria outbreak in Honduras, Central America, in January 1997. We tested 202 patients with fever and chills using thin and thick blood film microscopy. Sixteen patients lived in the city and the rest lived in rural areas. A total of 95 samples (47% were positive for malaria parasites. Seventy-nine percent (63/80 of the rural patients were infected with Plasmodium vivax and 21% (17/80 were infected with P. falciparum. In the urban area, all 15 infected patients had P. vivax malaria and none showed evidence of P. falciparum. Since previous reports indicate that falciparum malaria accounts for only 2% of the overall malaria infections in Honduras, the results reported here suggest that there is a dramatic increase in falciparum malaria in the area of Honduras investigated in this study.Notificamos los resultados de un estudio de un brote de malaria que se produjo en Honduras, Centroamérica, en enero de 1997. Sometimos a examen microscópico frotis delgados y frotis gruesos de la sangre de 202 pacientes con fiebre y escalofríos. Dieciséis pacientes eran habitantes de la zona urbana y el resto de la zona rural. Un total de 95 especímenes (47% fueron positivos a parásitos de la malaria. Setenta y ocho por ciento (62/80 de los pacientes del área rural estaban infestados con Plasmodium vivax y 22% (17/80 con P. falciparum. En la zona urbana, todos los 15 pacientes que estaban infestados tenían P. vivax y en ninguno se detectó P. falciparum. Ya que según informes previos la malaria de tipo falciparum representa solamente 2% de todos los casos de malaria en Honduras, nuestros resultados sugieren que hay un gran incremento del número de casos de malaria falciparum en la zona de Honduras en que se llevó a cabo esta investigación.

  16. Genetic and environmental control of seasonal carbohydrate dynamics in trees of diverse Pinus sylvestris populations.

    Science.gov (United States)

    Oleksyn, J.; Zytkowiak, R.; Karolewski, P.; Reich, P. B.; Tjoelker, M. G.

    2000-06-01

    We explored environmental and genetic factors affecting seasonal dynamics of starch and soluble nonstructural carbohydrates in needle and twig cohorts and roots of Scots pine (Pinus sylvestris L.) trees of six populations originating between 49 degrees and 60 degrees N, and grown under common garden conditions in western Poland. Trees of each population were sampled once or twice per month over a 3-year period from age 15 to 17 years. Based on similarity in starch concentration patterns in needles, two distinct groups of populations were identified; one comprised northern populations from Sweden and Russia (59-60 degrees N), and another comprised central European populations from Latvia, Poland, Germany and France (49-56 degrees N). Needle starch concentrations of northern populations started to decline in late spring and reached minimum values earlier than those of central populations. For all populations, starch accumulation in spring started when minimum air temperature permanently exceeded 0 degrees C. Starch accumulation peaked before bud break and was highest in 1-year-old needles, averaging 9-13% of dry mass. Soluble carbohydrate concentrations were lowest in spring and summer and highest in autumn and winter. There were no differences among populations in seasonal pattern of soluble carbohydrate concentrations. Averaged across all populations, needle soluble carbohydrate concentrations increased from about 4% of needle dry mass in developing current-year needles, to about 9% in 1- and 2-year-old needles. Root carbohydrate concentration exhibited a bimodal pattern with peaks in spring and autumn. Northern populations had higher concentrations of fine-root starch in spring and autumn than central populations. Late-summer carbohydrate accumulation in roots started only after depletion of starch in needles and woody shoots. We conclude that Scots pine carbohydrate dynamics depend partially on inherited properties that are probably related to phenology of root

  17. Validation of a Type 2 Diabetes Screening Tool in Rural Honduras

    Science.gov (United States)

    Milton, Evan C.; Herman, William H.; Aiello, Allison E.; Danielson, Kris R.; Mendoza-Avelarez, Milton O.; Piette, John D.

    2010-01-01

    OBJECTIVE To validate a low-cost tool for identifying diabetic patients in rural areas of Latin America. RESEARCH DESIGN AND METHODS A regression equation incorporating postprandial time and a random plasma glucose was used to screen 800 adults in Honduras. Patients with a probability of diabetes of ≥20% were asked to return for a fasting plasma glucose (FPG). A random fifth of those with a screener-based probability of diabetes Honduras and could be used to identify diabetic patients in poor clinics in Latin America. PMID:19918008

  18. Relationship between ancient bridges and population dynamics in the lower Yangtze River Basin, China.

    Science.gov (United States)

    Zhao, Yang; Jia, Xin; Lee, Harry F; Zhao, Hongqiang; Cai, Shuliang; Huang, Xianjin

    2017-01-01

    It has been suggested that population growth dynamics may be revealed by the geographic distribution and the physical structure of ancient bridges. Yet, this relationship has not been empirically verified. In this study, we applied the archaeological records for ancient bridges to reveal the population growth dynamics in the lower Yangtze River Basin in late imperial China. We investigated 89 ancient bridges in Yixing that were built during the Ming and Qing dynasties (AD1368-1911). Global Position System information and structure (length, width, and span) of those bridges was measured during our field investigations. Their distribution density was calculated by ArcGIS. The historical socio-economic dynamics of Yixing was inferred from the distribution and structure of ancient bridges. Based on the above information, the population growth dynamics in Yixing was projected. Our results show that 77 bridges were built in Yixing during the Qing dynasty, which is 6.41 times more than the number built during the Ming dynasty. In the Ming dynasty, bridges were built on pivotal routes; in the Qing dynasty, bridges were scattered across various places. Over the period, the density distribution of bridges shifted northwestward, while the average length and width of bridges decreased. The increasing number of bridges corresponded to population growth, largely attributable to massive clan migration from northern China during the Little Ice Age. The shift in the density distribution of bridges corresponded to the formation of settlements of large clans and the blossoming of Yixing Teapot handicrafts. The scattering and the reduction in average length and width of bridges was due to the dispersal of population and the associated formation of small settlements in the latter period. Our approach is innovative and robust, and could be employed to recover long-term historical population growth dynamics in other parts of China.

  19. Relationship between ancient bridges and population dynamics in the lower Yangtze River Basin, China.

    Directory of Open Access Journals (Sweden)

    Yang Zhao

    Full Text Available It has been suggested that population growth dynamics may be revealed by the geographic distribution and the physical structure of ancient bridges. Yet, this relationship has not been empirically verified. In this study, we applied the archaeological records for ancient bridges to reveal the population growth dynamics in the lower Yangtze River Basin in late imperial China. We investigated 89 ancient bridges in Yixing that were built during the Ming and Qing dynasties (AD1368-1911. Global Position System information and structure (length, width, and span of those bridges was measured during our field investigations. Their distribution density was calculated by ArcGIS. The historical socio-economic dynamics of Yixing was inferred from the distribution and structure of ancient bridges. Based on the above information, the population growth dynamics in Yixing was projected. Our results show that 77 bridges were built in Yixing during the Qing dynasty, which is 6.41 times more than the number built during the Ming dynasty. In the Ming dynasty, bridges were built on pivotal routes; in the Qing dynasty, bridges were scattered across various places. Over the period, the density distribution of bridges shifted northwestward, while the average length and width of bridges decreased. The increasing number of bridges corresponded to population growth, largely attributable to massive clan migration from northern China during the Little Ice Age. The shift in the density distribution of bridges corresponded to the formation of settlements of large clans and the blossoming of Yixing Teapot handicrafts. The scattering and the reduction in average length and width of bridges was due to the dispersal of population and the associated formation of small settlements in the latter period. Our approach is innovative and robust, and could be employed to recover long-term historical population growth dynamics in other parts of China.

  20. Spatial variation in population dynamics of Sitka mice in floodplain forests.

    Science.gov (United States)

    T.A. Hanley; J.C. Barnard

    1999-01-01

    Population dynamics and demography of the Sitka mouse, Peromyscus keeni sitkensis, were studied by mark-recapture live-trapping over a 4-year period in four floodplain and upland forest habitats: old-growth Sitka spruce (Picea sitchensis) floodplain; red alder (Alnus rubra) floodplain; beaver-pond...

  1. Smallholder dairy systems in the Kenya highlands: cattle population dynamics under increasing intensification

    NARCIS (Netherlands)

    Bebe, B.O.; Udo, H.M.J.; Rowlands, G.J.; Thorpe, W.

    2003-01-01

    A cross-sectional stratified random sample survey of 1755 households in the Kenya highlands was conducted between June 1996 and April 1998 to quantify cattle population dynamics in smallholder herds. The free-, semi-zero- and zero-grazing systems practised represented increasing levels of

  2. Cost-effectiveness of screening programs for Chlamydia trachomatis - A population-based dynamic approach

    NARCIS (Netherlands)

    Welte, R; Kretzschmar, M; Leidl, R; Van den Hoek, A; Jager, JC; Postma, MJ

    2000-01-01

    Background: Models commonly used for the economic assessment of chamydial screening programs do not consider population effects. Goal: To develop a novel dynamic approach for the economic evaluation of chlamydial prevention measures and to determine the cost-effectiveness of a general

  3. Transients drive the demographic dynamics of plant populations in variable environments

    DEFF Research Database (Denmark)

    McDonald, Jenni L; Stott, Iain; Townley, Stuart

    2016-01-01

    clear patterns related to growth form. We find a surprising tendency for plant populations to boom rather than bust in response to temporal changes in vital rates and that stochastic growth rates increase with increasing tendency to boom. Synthesis. Transient dynamics contribute significantly...

  4. Dynamics of weed populations : spatial pattern formation and implications for control

    NARCIS (Netherlands)

    Wallinga, J.

    1998-01-01

    Modelling studies were carried out to analyse spatio-temporal dynamics of annual weed populations and to identify the key factors that determine the long-term herbicide use of weed control programmes. Three different weed control programmes were studied.

    In the first weed

  5. Cell mass and cell cycle dynamics of an asynchronous budding yeast population

    DEFF Research Database (Denmark)

    Lencastre Fernandes, Rita; Carlquist, Magnus; Lundin, Luisa

    2013-01-01

    of model predictions for cell property distributions against experimental data is scarce. This study focuses on the experimental and mathematical description of the dynamics of cell size and cell cycle position distributions, of a population of Saccharomyces cerevisiae, in response to the substrate...

  6. Application of homotopy-perturbation method to nonlinear population dynamics models

    International Nuclear Information System (INIS)

    Chowdhury, M.S.H.; Hashim, I.; Abdulaziz, O.

    2007-01-01

    In this Letter, the homotopy-perturbation method (HPM) is employed to derive approximate series solutions of nonlinear population dynamics models. The nonlinear models considered are the multispecies Lotka-Volterra equations. The accuracy of this method is examined by comparison with the available exact and the fourth-order Runge-Kutta method (RK4)

  7. Dynamic-landscape metapopulation models predict complex response of wildlife populations to climate and landscape change

    Science.gov (United States)

    Thomas W. Bonnot; Frank R. Thompson; Joshua J. Millspaugh

    2017-01-01

    The increasing need to predict how climate change will impact wildlife species has exposed limitations in how well current approaches model important biological processes at scales at which those processes interact with climate. We used a comprehensive approach that combined recent advances in landscape and population modeling into dynamic-landscape metapopulation...

  8. Population dynamics of Ascaridia galli following single infection in young chickens

    DEFF Research Database (Denmark)

    Ferdushy, Tania; Luna Olivares, Luz Adilia; Nejsum, Peter

    2013-01-01

    SUMMARY The population dynamics of Ascaridia galli was studied in 70 ISA Brown layer pullets, 42 of them were each experimentally infected with 500 embryonated A. galli eggs and 28 chickens were kept as uninfected controls. Six chickens from the infected group and 4 from the control group were...

  9. Seasonal population dynamics of Zeuxapta seriolae (Monogenea: Heteraxinidae) parasitising Seriola dumerili (Carangidae) in the Western Mediterranean

    Czech Academy of Sciences Publication Activity Database

    Repulles-Albelda, A.; Kostadinova, Aneta; Raga, J. A.; Montero, F. E.

    2013-01-01

    Roč. 193, 1-3 (2013), s. 163-171 ISSN 0304-4017 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : Zeuxapta seriolae * Seriola dumerili * Monogenea * Population dynamics * Western Mediterranean Subject RIV: EH - Ecology, Behaviour Impact factor: 2.545, year: 2013

  10. Population dynamics, life-history traits of and habitat use by two ...

    African Journals Online (AJOL)

    Population dynamics and life-history traits of two sympatric nothobranchiid killifishes, Epiplatys bifasciatus and E. spilargyreius, were studied for 24 months in an intermittent stream in the Kainji Lake Basin, Nigeria. Epiplatys bifasciatus was more abundant throughout the study period, but monthly abundance of both species ...

  11. Dynamic Behaviour of a Population of Controlled-by-price Demand Side Resources

    DEFF Research Database (Denmark)

    Sossan, Fabrizio; Han, Xue; Bindner, Henrik W.

    2014-01-01

    It is described that controlling or shedding by price the power consumption of a population of thermostatic loads introduces in the aggregate consumption dynamic effects th at cannot be disregarded if electrical flexible demand is meant to supply power system services. It is shown that inducing...

  12. What controls the population dynamics of the invasive thistle Carduus nutans in its native range?

    NARCIS (Netherlands)

    Jongejans, E.; Sheppard, A.W.; Shea, K.

    2006-01-01

    1. The invasive thistle Carduus nutans causes major economic losses in the Americas, Australia and New Zealand. For the first time, we have modelled its population dynamics in its native range, Eurasia, where it rarely reaches problematic densities, in order to identify ways to improve management

  13. The dynamics of diverse segmental amplifications in populations of Saccharomyces cerevisiae adapting to strong selection.

    Science.gov (United States)

    Payen, Celia; Di Rienzi, Sara C; Ong, Giang T; Pogachar, Jamie L; Sanchez, Joseph C; Sunshine, Anna B; Raghuraman, M K; Brewer, Bonita J; Dunham, Maitreya J

    2014-03-20

    Population adaptation to strong selection can occur through the sequential or parallel accumulation of competing beneficial mutations. The dynamics, diversity, and rate of fixation of beneficial mutations within and between populations are still poorly understood. To study how the mutational landscape varies across populations during adaptation, we performed experimental evolution on seven parallel populations of Saccharomyces cerevisiae continuously cultured in limiting sulfate medium. By combining quantitative polymerase chain reaction, array comparative genomic hybridization, restriction digestion and contour-clamped homogeneous electric field gel electrophoresis, and whole-genome sequencing, we followed the trajectory of evolution to determine the identity and fate of beneficial mutations. During a period of 200 generations, the yeast populations displayed parallel evolutionary dynamics that were driven by the coexistence of independent beneficial mutations. Selective amplifications rapidly evolved under this selection pressure, in particular common inverted amplifications containing the sulfate transporter gene SUL1. Compared with single clones, detailed analysis of the populations uncovers a greater complexity whereby multiple subpopulations arise and compete despite a strong selection. The most common evolutionary adaptation to strong selection in these populations grown in sulfate limitation is determined by clonal interference, with adaptive variants both persisting and replacing one another.

  14. Nonbreeding-Season Drivers of Population Dynamics in Seasonal Migrants: Conservation Parallels Across Taxa

    Directory of Open Access Journals (Sweden)

    Anna M. Calvert

    2009-12-01

    Full Text Available For seasonal migrants, logistical constraints have often limited conservation efforts to improving survival and reproduction during the breeding season only. Yet, mounting empirical evidence suggests that events occurring throughout the migratory life cycle can critically alter the demography of many migrant species. Herein, we build upon recent syntheses of avian migration research to review the role of non-breeding seasons in determining the population dynamics and fitness of diverse migratory taxa, including salmonid fishes, marine mammals, ungulates, sea turtles, butterflies, and numerous bird groups. We discuss several similarities across these varied migrants: (i non-breeding survivorship tends to be a strong driver of population growth; (ii non-breeding events can affect fitness in subsequent seasons through seasonal interactions at individual- and population-levels; (iii broad-scale climatic influences often alter non-breeding resources and migration timing, and may amplify population impacts through covariation among seasonal vital rates; and (iv changes to both stationary and migratory non-breeding habitats can have important consequences for abundance and population trends. Finally, we draw on these patterns to recommend that future conservation research for seasonal migrants will benefit from: (1 more explicit recognition of the important parallels among taxonomically diverse migratory animals; (2 an expanded research perspective focused on quantification of all seasonal vital rates and their interactions; and (3 the development of detailed population projection models that account for complexity and uncertainty in migrant population dynamics.

  15. Gender relations and reproductive decision making in Honduras.

    Science.gov (United States)

    Speizer, Ilene S; Whittle, Lisa; Carter, Marion

    2005-09-01

    Gender differences influence decision making about reproductive health. Most information on reproductive health decision making in Latin America has come from women's reports of men's involvement. Data were collected in Honduras in 2001 through two national surveys that used independent samples of men aged 15-59 years and women aged 15-49. Bivariate and multivariate analyses were used to identify factors associated with male-centered decision-making attitudes and behaviors regarding family size and family planning use. Overall, 25% of women and 28% of men said that men alone should be responsible for at least one of these reproductive decisions, and 27% of women and 21% of men said that the man in their household made one or both decisions. For women, having no children and being in a consensual union were each associated with holding male-centered decision-making attitudes; having less than a secondary education, being of medium or low socioeconomic status and living in a rural area were each associated with male-centered decision making. Among men, having less than secondary education and being in a consensual union were each associated with male-centered decision-making attitudes and behavior. Women who had ever used or were currently using modern methods were significantly less likely to hold attitudes supporting male-centered decision-making than were those who relied on traditional methods and those who had never used a modern method. Programs should recognize power imbalances between genders that affect women's ability to meet their stated fertility desires. In rural areas, programs should target men, encouraging them to communicate with their wives on reproductive decisions.

  16. Los ferrocarriles de la República de Honduras

    Directory of Open Access Journals (Sweden)

    García, Marcela Alejandra

    1996-06-01

    Full Text Available Not available.

    El desarrollo ferroviario de Honduras respondió, ante todo, a las aspiraciones y necesidades del capital extranjero, fundamentalmente norteamericano. El descubrimiento del oro en California, primero, planteó el interés por abrir vías de comunicación en Centroamérica que comunicasen el Océano Atlántico y el Pacífico. La explotación del banano, después, implicó la explotación de una serie de líneas de ferrocarril que aseguraron el abastecimiento de este producto en el mercado norteamericano. La intención de este trabajo es mostrar la forma en que el desarrollo ferroviario hondureño dependió de las oscilaciones del negocio bananero. Como medio de transporte, adoleció prácticamente de efectos multiplicadores sobre el desarrollo económico y social del país, controlado por las empresas bananeras, concentradas en la región norte del país. Concluido el ciclo alcista de las economías exportadoras y, enfrentado a la competencia de nuevos medios de transporte y a la relativa diversificación económica de la segunda mitad del siglo XX en el marco del Mercado Común Centroamericano, se verá sumido en una crisis de carácter estructural que explica su lamentable estado actual.

  17. A community-driven hypertension treatment group in rural Honduras.

    Science.gov (United States)

    Reiger, Sheridan; Harris, Jeffrey R; Chan, Kwun Chuen Gary; Oqueli, Hector Lopez; Kohn, Marlana

    2015-01-01

    We formed a self-funded hypertension treatment group in a resource-poor community in rural Honduras. After training community health workers and creating protocols for standardized treatment, we used group membership fees to maintain the group, purchase generic medications in bulk on the local market, and hire a physician to manage treatment. We then assessed whether participation in the group improved treatment, medication adherence, and hypertension control. This is a program evaluation using quasi-experimental design and no control group. Using data from the 86 members of the hypertension treatment group, we analyzed baseline and follow-up surveys of members, along with 30 months of clinical records of treatment, medication adherence, and blood pressure readings. Our initial hypertension needs assessment revealed that at baseline, community hypertensives relied on the local Ministry of Health clinic as their source of anti-hypertensive medications and reported that irregular supply interfered with medication adherence. At baseline, hypertension group members were mainly female, overweight or obese, physically active, non-smoking, and non-drinking. After 30 months of managing the treatment group, we found a significant increase in medication adherence, from 54.8 to 76.2% (p<0.01), and hypertension control (<140/90 mmHg), from 31.4 to 54.7% (p<0.01). We also found a mean monthly decrease of 0.39 mmHg in systolic blood pressure (p<0.01). At the end of the 30-month observation period, the local Ministry of Health system had increased provision of low-cost anti-hypertensive medications and adopted the hypertension treatment group's treatment protocols. Formation of a self-funded, community-based hypertension treatment group in a rural, resource-poor community is feasible, and group participation may improve treatment, medication adherence, and hypertension control and can serve as a political driver for improving hypertension treatment services provided by the public

  18. Employment-generating projects for the energy and minerals sectors of Honduras. Proyectos generadores de empleos para los sectores energetico y minero de Honduras

    Energy Technology Data Exchange (ETDEWEB)

    Frank, J.A.

    1988-12-01

    A mission to Honduras invited by the Government of Honduras and sponsored by the Organization of American States addressed the generation of employment in various areas of interest to the country. The mission was made up of experts from numerous countries and international agencies. In the energy sector, the mission recommended consolidating the sector under a coordinating body; carrying out projects to promote reforestation, tree farms, and rational forest utilization; encouraging industrial energy conservation; developing alternative energy sources; and promoting rural electrification and expansion of the electrical grid. In the mining sector, the mission supported promotion and technical assistance for small gold-leaching and placer operations, the national mineral inventory, detailed exploration of promising sites, and the development of a mining school. 13 refs., 7 tabs.

  19. Population dynamics of graphene driven by a few-cycle laser pulse

    Science.gov (United States)

    Ding, Chunling; Yu, Rong; Hao, Xiangying; Zhang, Duo; Zu, Fengxia

    2017-06-01

    We study the time evolution of the populations in a two-dimensional (2D) graphene system by employing a few-cycle laser pulse with a linear polarization. Specifically, we present a comparative numerical analysis of the population dynamics of graphene in three different model configurations. Our results show that the Rabi-like oscillations and intraband population inversion can be observed in the population spectrum, which originated from the periodicity of a few-cycle laser pulse and the intraband Coulomb scattering. Also, coherent population oscillations are produced across the Dirac point when the Rabi frequency of the laser field which is used to couple the interband transition is much larger than that couples the intraband transition, and vice versa. These investigations may be helpful to enhance the performance of graphene-based ultrafast electronic and optoelectronic devices, including light-emitting devices, touch screens, photodetectors, and ultrafast lasers.

  20. Population dynamics of the epiphytic bromeliad Tillandsia butzii in cloud forest

    Science.gov (United States)

    Toledo-Aceves, Tarin; Hernández-Apolinar, Mariana

    2016-02-01

    Epiphytes are a major component of tropical montane cloud forests. Over-exploitation and forest loss and degradation affect remnant populations. In this study, we analysed the population dynamics of the epiphytic bromeliad Tillandsia butzii over a 2-y period in a tropical montane cloud forest fragment in southern Mexico. Matrix analysis revealed that the T. butzii population is likely to be stable at the study site. On average the λ value did not differ significantly from unity: λ (95% confidence interval) = 0.978 (0.936-1.001). λ was highly influenced by stasis, to a lesser extent by growth and only slightly by fecundity. Overall, adult plant stasis and phalanx growth habit played a fundamental role in population maintenance. T. butzii tolerance to xeric conditions may contribute to population stability in the studied region.

  1. Population dynamic of the swallowtail butterfly, Papilio polytes (Lepidoptera: Papilionidae in dry and wet seasons

    Directory of Open Access Journals (Sweden)

    SUWARNO

    2010-01-01

    Full Text Available Suwarno (2010 Population dynamic of the swallowtail butterfly, Papilio polytes (Lepidoptera: Papilionidae in dry and wet seasons. Biodiversitas 11: 19-23. The population dynamic of Papilio polytes L. (Lepidoptera: Papilionidae in dry and wet seasons was investigated in the citrus orchard in Tasek Gelugor, Pulau Pinang, Malaysia. Population of immature stages of P. polytes was observed alternate day from January to March 2006 (dry season, DS, from April to July 2006 (secondary wet season, SWS, and from October to December 2006 (primary wet season, PWS. The population dynamics of the immature stages of P. polytes varied between seasons. The immature stages of P. polytes are more abundance and significantly different in the PWS than those of the DS and the SWS. The larval densities in all seasons decreased with progressive development of the instar stages. Predators and parasitoids are the main factor in regulating the population abundance of immature stages of P. polytes. There were positive correlations between the abundance of immature stages of P. polytes and their natural enemies abundance in each season. Ooencyrtus papilioni Ashmead (Hymenoptera: Encyrtidae is the most egg parasitoid. Oxyopes quadrifasciatus L. Koch. and O. elegans L. Koch. (Araneae: Oxyopidae are the main predators in the young larvae, meanwhile Sycanus dichotomus Stal. (Heteroptera: Reduviidae, Calotes versicolor Fitzinger (Squamata: Agamidae, birds and praying mantis attacked the older larvae.

  2. Population ecology, nonlinear dynamics, and social evolution. I. Associations among nonrelatives.

    Science.gov (United States)

    Avilés, Leticia; Abbot, Patrick; Cutter, Asher D

    2002-02-01

    Using an individual-based and genetically explicit simulation model, we explore the evolution of sociality within a population-ecology and nonlinear-dynamics framework. Assuming that individual fitness is a unimodal function of group size and that cooperation may carry a relative fitness cost, we consider the evolution of one-generation breeding associations among nonrelatives. We explore how parameters such as the intrinsic rate of growth and group and global carrying capacities may influence social evolution and how social evolution may, in turn, influence and be influenced by emerging group-level and population-wide dynamics. We find that group living and cooperation evolve under a wide range of parameter values, even when cooperation is costly and the interactions can be defined as altruistic. Greater levels of cooperation, however, did evolve when cooperation carried a low or no relative fitness cost. Larger group carrying capacities allowed the evolution of larger groups but also resulted in lower cooperative tendencies. When the intrinsic rate of growth was not too small and control of the global population size was density dependent, the evolution of large cooperative tendencies resulted in dynamically unstable groups and populations. These results are consistent with the existence and typical group sizes of organisms ranging from the pleometrotic ants to the colonial birds and the global population outbreaks and crashes characteristic of organisms such as the migratory locusts and the tree-killing bark beetles.

  3. Dynamic assessments of population exposure to urban greenspace using multi-source big data.

    Science.gov (United States)

    Song, Yimeng; Huang, Bo; Cai, Jixuan; Chen, Bin

    2018-09-01

    A growing body of evidence has proven that urban greenspace is beneficial to improve people's physical and mental health. However, knowledge of population exposure to urban greenspace across different spatiotemporal scales remains unclear. Moreover, the majority of existing environmental assessments are unable to quantify how residents enjoy their ambient greenspace during their daily life. To deal with this challenge, we proposed a dynamic method to assess urban greenspace exposure with the integration of mobile-phone locating-request (MPL) data and high-spatial-resolution remote sensing images. This method was further applied to 30 major cities in China by assessing cities' dynamic greenspace exposure levels based on residents' surrounding areas with different buffer scales (0.5km, 1km, and 1.5km). Results showed that regarding residents' 0.5-km surrounding environment, Wenzhou and Hangzhou were found to be with the greenest exposure experience, whereas Zhengzhou and Tangshan were the least ones. The obvious diurnal and daily variations of population exposure to their surrounding greenspace were also identified to be highly correlated with the distribution pattern of urban greenspace and the dynamics of human mobility. Compared with two common measurements of urban greenspace (green coverage rate and green area per capita), the developed method integrated the dynamics of population distribution and geographic locations of urban greenspace into the exposure assessment, thereby presenting a more reasonable way to assess population exposure to urban greenspace. Additionally, this dynamic framework could hold potential utilities in supporting urban planning studies and environmental health studies and advancing our understanding of the magnitude of population exposure to greenspace at different spatiotemporal scales. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Assessing the status and trend of bat populations across broad geographic regions with dynamic distribution models

    Science.gov (United States)

    Rodhouse, Thomas J.; Ormsbee, Patricia C.; Irvine, Kathryn M.; Vierling, Lee A.; Szewczak, Joseph M.; Vierling, Kerri T.

    2012-01-01

    Bats face unprecedented threats from habitat loss, climate change, disease, and wind power development, and populations of many species are in decline. A better ability to quantify bat population status and trend is urgently needed in order to develop effective conservation strategies. We used a Bayesian autoregressive approach to develop dynamic distribution models for Myotis lucifugus, the little brown bat, across a large portion of northwestern USA, using a four-year detection history matrix obtained from a regional monitoring program. This widespread and abundant species has experienced precipitous local population declines in northeastern USA resulting from the novel disease white-nose syndrome, and is facing likely range-wide declines. Our models were temporally dynamic and accounted for imperfect detection. Drawing on species–energy theory, we included measures of net primary productivity (NPP) and forest cover in models, predicting that M. lucifugus occurrence probabilities would covary positively along those gradients.

  5. Population Dynamics of Biota on the Roots of Azolla microphylla Kaulfuss

    Directory of Open Access Journals (Sweden)

    NITA ETIKAWATI

    2000-01-01

    Full Text Available Azolla was a special fern that their associations with Anabaena azollae able to fix free nitrogen from air, to produce protein. Although by the ages, biota diversity those habits on the roots of Azolla increased and effected to protein concentration. The research was to find out population dynamics of biota on the roots of Azolla microphylla Kaulfuss and the growth peak. This study used Completely Randomized Design with 10 kinds of biota, i.e. bacteria, Fungi, Actinomycetes, Protozoa, Alga, Crustacean, Rotifers, Coelenterate, Insect and Molluscs, and it was used 3 replications. Research was conducted within 4 weeks and the populations of biota were observed every week. Data were statistically analyzed using Analysis Variant and Duncan’s Multiple Range Test. The population dynamics of biota on the roots of Azolla microphylla Kaulfuss were influenced on its quantity and composition, and the growth peak is done in 2nd week.

  6. Population and phase dynamics of F=1 spinor condensates in an external magnetic field

    International Nuclear Information System (INIS)

    Romano, D.R.; Passos, E.J.V. de

    2004-01-01

    We show that the classical dynamics underlying the mean-field description of homogeneous mixtures of spinor F=1 Bose-Einstein condensates in an external magnetic field is integrable as a consequence of number conservation and axial symmetry in spin space. The population dynamics depends only on the quadratic term of the Zeeman energy and on the strength of the spin-dependent term of the atom-atom interaction. We determine the equilibrium populations as function of the ratio of these two quantities and the miscibility of the hyperfine components in the ground state spinors are thoroughly discussed. Outside the equilibrium, the populations are always a periodic function of time where the periodic motion can be a libration or a rotation. Our studies also indicate the absence of metastability

  7. Diffusion of non-traditional cookstoves across western Honduras: A social network analysis

    International Nuclear Information System (INIS)

    Ramirez, Sebastian; Dwivedi, Puneet; Ghilardi, Adrian; Bailis, Robert

    2014-01-01

    A third of the world's population uses inefficient biomass stoves, contributing to severe health problems, forest degradation, and climate change. Clean burning, fuel-efficient, non-traditional cookstoves (NTCS) are a promising solution; however, numerous projects fail during the diffusion process. We use social network analysis to reveal patterns driving a successful stove intervention in western Honduras. The intervention lacks formal marketing, but has spread across a wide area in just a few years. To understand the process, we map the social network of active community members who drove diffusion across a large swath of the country. We find that most ACMs heard about stoves twice before sharing information about it with others and introducing the stove into their own communities. On average, the social distance between ACMs and the project team is 3 degrees of separation. Both men and women are critical to the diffusion process, but men tend to communicate over longer distances, while women principally communicate over shorter distances. Government officials are also crucial to diffusion. Understanding how information moves through social networks and across geographic space allows us to theorize how knowledge about beneficial technologies spreads in the absence of formal marketing and inform policies for NTCS deployment worldwide. - Highlights: • We build a chain of referrals to track spread of information about non traditional cookstoves. • We find differences among gender and occupations that should inform policy. • People hear about the stoves twice before becoming suppliers of information. • Government officials play a substantial role in the diffusion. • Males play leading role in diffusion over long distances, females in short distances

  8. Associations between seasonal influenza and meteorological parameters in Costa Rica, Honduras and Nicaragua.

    Science.gov (United States)

    Soebiyanto, Radina P; Clara, Wilfrido A; Jara, Jorge; Balmaseda, Angel; Lara, Jenny; Lopez Moya, Mariel; Palekar, Rakhee; Widdowson, Marc-Alain; Azziz-Baumgartner, Eduardo; Kiang, Richard K

    2015-11-04

    Seasonal influenza affects a considerable proportion of the global population each year. We assessed the association between subnational influenza activity and temperature, specific humidity and rainfall in three Central America countries, i.e. Costa Rica, Honduras and Nicaragua. Using virologic data from each country's national influenza centre, rainfall from the Tropical Rainfall Measuring Mission and air temperature and specific humidity data from the Global Land Data Assimilation System, we applied logistic regression methods for each of the five sub-national locations studied. Influenza activity was represented by the weekly proportion of respiratory specimens that tested positive for influenza. The models were adjusted for the potentially confounding co-circulating respiratory viruses, seasonality and previous weeks' influenza activity. We found that influenza activity was proportionally associated (P<0.05) with specific humidity in all locations [odds ratio (OR) 1.21-1.56 per g/kg], while associations with temperature (OR 0.69-0.81 per °C) and rainfall (OR 1.01-1.06 per mm/day) were location-dependent. Among the meteorological parameters, specific humidity had the highest contribution (~3-15%) to the model in all but one location. As model validation, we estimated influenza activity for periods, in which the data was not used in training the models. The correlation coefficients between the estimates and the observed were ≤0.1 in 2 locations and between 0.6-0.86 in three others. In conclusion, our study revealed a proportional association between influenza activity and specific humidity in selected areas from the three Central America countries.

  9. Seasonal population dynamics of Brachyiulus jawlowskii (Diplopoda, Julidae in the Dnieper river arena

    Directory of Open Access Journals (Sweden)

    N. G. Gudym

    2016-06-01

    Full Text Available We have researched the population dynamics of Brachyiulus jawlowskii Lohmander, 1928 in the arena of the Dnepr river (within the "Dnieper-Orilsky” Nature Reserve and also present a full picture of the habitat distribution of Julidae within the researched area. The tested models were basic types of arena biogeocenosis: sand steppe, black maple forests, artificial pine plantations, deciduous forest, meadow and swamp. Variation in population density of B. jawlowskii is determined by biotopical features. The swamp and meadow habitats can be characterized by the highest level of population dynamics. B. jawlowskii plays the greatest role in the herpetobiont grouping in swamp and oak forest habitats (6.7% and 4.6% respectively. In other types of habitat this species composes 0.1–3.5% of the total abundance of this group. The highest abundance dynamic was reached by the Julidae cenopopulations which inhabit the swamp, oak forest and meadow habitats. B. jawlowskii occupies a relatively significant share in the herpetobiont communities of these habitats. Thus, the indicators of absolute number of this species and its relative participation in the herpertobiont grouping indicate the preference of this species for marsh, oak forest and meadow habitats. These habitats can be characterized by an excessive or moderate level of edaphotopic humidification. The ecosystem of the steppe zone of Ukraine is subject to significant human impact. In nature reserves, this effect is minimized, which permits research to be conducted on regimes of natural population dynamics. We established that B. jawlowskii inhabits all habitats investigated within the arena zone of the Dnepr river. This indicates that this is an environmentally flexible Julidae species. The population dynamics of B. jawlowskii can be characterized by three distinct periods: spring-summer, summer and autumn. Each of these periods is characterized by a distinct population dynamic, but throughout the

  10. Dynamics of a Lotka-Volterra type model with applications to marine phage population dynamics

    International Nuclear Information System (INIS)

    Gavin, C; Pokrovskii, A; Prentice, M; Sobolev, V

    2006-01-01

    The famous Lotka-Volterra equations play a fundamental role in the mathematical modeling of various ecological and chemical systems. A new modification of these equations has been recently suggested to model the structure of marine phage populations, which are the most abundant biological entities in the biosphere. The purpose of the paper is: (i) to make some methodical remarks concerning this modification; (ii) to discuss new types of canards which arise naturally in this context; (iii) to present results of some numerical experiments

  11. Maintenance of algal endosymbionts in Paramecium bursaria: a simple model based on population dynamics.

    Science.gov (United States)

    Iwai, Sosuke; Fujiwara, Kenji; Tamura, Takuro

    2016-09-01

    Algal endosymbiosis is widely distributed in eukaryotes including many protists and metazoans, and plays important roles in aquatic ecosystems, combining phagotrophy and phototrophy. To maintain a stable symbiotic relationship, endosymbiont population size in the host must be properly regulated and maintained at a constant level; however, the mechanisms underlying the maintenance of algal endosymbionts are still largely unknown. Here we investigate the population dynamics of the unicellular ciliate Paramecium bursaria and its Chlorella-like algal endosymbiont under various experimental conditions in a simple culture system. Our results suggest that endosymbiont population size in P. bursaria was not regulated by active processes such as cell division coupling between the two organisms, or partitioning of the endosymbionts at host cell division. Regardless, endosymbiont population size was eventually adjusted to a nearly constant level once cells were grown with light and nutrients. To explain this apparent regulation of population size, we propose a simple mechanism based on the different growth properties (specifically the nutrient requirements) of the two organisms, and based from this develop a mathematical model to describe the population dynamics of host and endosymbiont. The proposed mechanism and model may provide a basis for understanding the maintenance of algal endosymbionts. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Fortune favours the brave: Movement responses shape demographic dynamics in strongly competing populations.

    Science.gov (United States)

    Potts, Jonathan R; Petrovskii, Sergei V

    2017-05-07

    Animal movement is a key mechanism for shaping population dynamics. The effect of interactions between competing animals on a population's survival has been studied for many decades. However, interactions also affect an animal's subsequent movement decisions. Despite this, the indirect effect of these decisions on animal survival is much less well-understood. Here, we incorporate movement responses to foreign animals into a model of two competing populations, where inter-specific competition is greater than intra-specific competition. When movement is diffusive, the travelling wave moves from the stronger population to the weaker. However, by incorporating behaviourally induced directed movement towards the stronger population, the weaker one can slow the travelling wave down, even reversing its direction. Hence movement responses can switch the predictions of traditional mechanistic models. Furthermore, when environmental heterogeneity is combined with aggressive movement strategies, it is possible for spatially segregated co-existence to emerge. In this situation, the spatial patterns of the competing populations have the unusual feature that they are slightly out-of-phase with the environmental patterns. Finally, incorporating dynamic movement responses can also enable stable co-existence in a homogeneous environment, giving a new mechanism for spatially segregated co-existence. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Seasonal dynamics of snail populations in coastal Kenya: Model calibration and snail control

    Science.gov (United States)

    Gurarie, D.; King, C. H.; Yoon, N.; Wang, X.; Alsallaq, R.

    2017-10-01

    A proper snail population model is important for accurately predicting Schistosoma transmission. Field data shows that the overall snail population and that of shedding snails have a strong pattern of seasonal variation. Because human hosts are infected by the cercariae released from shedding snails, the abundance of the snail population sets ultimate limits on human infection. For developing a predictive dynamic model of schistosome infection and control strategies we need realistic snail population dynamics. Here we propose two such models based on underlying environmental factors and snail population biology. The models consist of two-stage (young-adult) populations with resource-dependent reproduction, survival, maturation. The key input in the system is seasonal rainfall which creates snail habitats and resources (small vegetation). The models were tested, calibrated and validated using dataset collected in Msambweni (coastal Kenya). Seasonal rainfall in Msambweni is highly variable with intermittent wet - dry seasons. Typical snail patterns follow precipitation peaks with 2-4-month time-lag. Our models are able to reproduce such seasonal variability over extended period of time (3-year study). We applied them to explore the optimal seasonal timing for implementing snail control.

  14. Creating Sustainable Education Projects in Roatán, Honduras through Continuous Process Improvement

    Science.gov (United States)

    Raven, Arjan; Randolph, Adriane B.; Heil, Shelli

    2010-01-01

    The investigators worked together with permanent residents of Roatán, Honduras on sustainable initiatives to help improve the island's troubled educational programs. Our initiatives focused on increasing the number of students eligible and likely to attend a university. Using a methodology based in continuous process improvement, we developed…

  15. Crisis Discourses and Technology Regulation in a Weak State: Response to a Pesticide Disaster in Honduras

    NARCIS (Netherlands)

    Jansen, K.

    2003-01-01

    Hurricane Mitch hit Honduras in October 1998, leaving a trail of death, injury and devastating damage. As it tore through the country, the hurricane damaged a number of warehouses which contained pesticides, resulting in the discharge of more than 70 tonnes of pesticides into the environment. This

  16. How Patronage Politics Undermines Parental Participation and Accountability: Community-Managed Schools in Honduras and Guatemala

    Science.gov (United States)

    Altschuler, Daniel

    2013-01-01

    This article shows how patronage politics affects a popular international education model: community-managed schools (CMS). Focusing on Honduras's CMS initiative, PROHECO (Programa Hondureno de Educacion Comunitaria), I demonstrate how patronage can undermine CMS accountability. Whereas supporters argue that CMS increases accountability, partisan…

  17. 75 FR 24734 - Extension of the Designation of Honduras for Temporary Protected Status and Automatic Extension...

    Science.gov (United States)

    2010-05-05

    ... for food production and the increased likelihood of flooding, landslides, and forest fires. All health... Service. Box 6943, Chicago, IL 60680- 6943. You are applying for the first time as U.S. Citizenship and a... 6943, Chicago, IL 60680-6943. You are using a Non-US Postal Service USCIS, Attn: TPS Honduras, 131...

  18. La Persistencia de la Pobreza Rural en Honduras, Nicaragua y Bolivia: un Fracaso del Neoliberalismo

    NARCIS (Netherlands)

    C. Kay (Cristóbal)

    2009-01-01

    textabstractLos documentos de estrategia de lucha contra la pobreza, preparados por los gobiernos mediante un proceso en el que participan instituciones internacionales y actores de la sociedad civil, no dieron los resultados previstos. El artículo analiza los casos de Honduras, Nicaragua y Bolivia

  19. Decentralization and Educational Performance: Evidence from the PROHECO Community School Program in Rural Honduras

    Science.gov (United States)

    Di Gropello, Emanuela; Marshall, Jeffery H.

    2011-01-01

    We analyze the effectiveness of the Programa Hondureno de Educacion Comunitaria (PROHECO) community school program in rural Honduras. The data include standardized tests and extensive information on school, teacher, classroom and community features for 120 rural schools drawn from 15 states. Using academic achievement decompositions we find that…

  20. Integrating health promotion and disease prevention interventions with vaccination in Honduras.

    Science.gov (United States)

    Molina-Aguilera, Ida Berenice; Mendoza-Rodríguez, Lourdes Otilia; Palma-Ríos, María Aparicia; Danovaro-Holliday, M Carolina

    2012-03-01

    We sought to review and describe health interventions integrated with immunization delivery, both routine and during national vaccination weeks, in Honduras between 1991 and 2009. We compiled and examined all annual evaluation reports from the national Expanded Program on Immunization and reports from the national vaccination weeks (NVWs) between 1988 and 2009. We held discussions with the persons responsible for immunization and other programs in the Health Secretary of Honduras for the same time period. Since 1991, several health promotion and disease prevention interventions have been integrated with immunization delivery, including vitamin A supplementation (since 1994), folic acid supplementation (2003), early detection of retinoblastoma (since 2003), breastfeeding promotion (2007-2008), and disease control activities during public health emergencies, such as cholera control (1991-1992) and dengue control activities (since 1991, when a dengue emergency coincides with the NVW). Success factors included sufficient funds and supplies to ensure sustainability and joint planning, delivery, and monitoring. Several health interventions have been integrated with vaccination delivery in Honduras for nearly 20 years. The immunization program in Honduras has sufficient structure, organization, acceptance, coverage, and experience to achieve successful integration with health interventions if carefully planned and suitably implemented.

  1. Real-Time Evolution of Zika Virus Disease Outbreak, Roatán, Honduras.

    Science.gov (United States)

    Brooks, Trevor; Roy-Burman, Arup; Tuholske, Cascade; Busch, Michael P; Bakkour, Sonia; Stone, Mars; Linnen, Jeffrey M; Gao, Kui; Coleman, Jayleen; Bloch, Evan M

    2017-08-01

    A Zika virus disease outbreak occurred in Roatán, Honduras, during September 2015-July 2016. Blood samples and clinical information were obtained from 183 patients given a clinical diagnosis of suspected dengue virus infection. A total of 79 patients were positive for Zika virus, 13 for chikungunya virus, and 6 for dengue virus.

  2. First report of 'Candidatus Liberibacter solanacearum' associated with psylllid-affected tobacco in Honduras

    Science.gov (United States)

    Tobacco plants with symptoms resembling those associated with the psyllid Bactericera cockerelli and the bacterium “Candidatus Liberibacter solanacearum” (Lso) were observed in April of 2012 in heavily B. cockerelli-infested commercial fields in the Department of El-Paraíso, Honduras; all cultivars ...

  3. First report of Dolabra nepheliae associated with corky bark disease of Rambutan and Pulasan in Honduras

    Science.gov (United States)

    Rambutan (Nephelium lappaceum L., Sapindaceae) was first introduced into Honduras in 1927 but commercial production was not started until after 1980 when cultivation of pulasan (N. mutabile Blume) was initiated. In the last decade these crops have become popular as exotic fruit for export to North A...

  4. Cultural Capital and Innovative Pedagogy: A Case Study among Indigenous Communities in Mexico and Honduras

    Science.gov (United States)

    Gregorcic, Marta

    2009-01-01

    This article introduces case studies of innovative approaches to pedagogy among indigenous Mayan communities in Chiapas (Mexico) and Lencan communities in Intibuca (Honduras). Innovative approaches to researching alternative theories and practices of pedagogy are used by the author to develop an epistemology of critical pedagogy and its potential…

  5. A new extant species of Electribius Crowson from Honduras (Coleoptera: Elateroidea: Artematopodidae).

    Science.gov (United States)

    Gimmel, Matthew L; Bocakova, Milada

    2015-03-05

    A new extant species of Electribius Crowson, E. llamae sp.n., is described from Cusuco National Park, Cortés Province, Honduras. This new species lacks one of the supposed autapomorphies of the genus; therefore the definition of the genus requires modification. A revised key to the known extant species is presented, and their known distributions are mapped.

  6. Using "EC-Assess" to Assess a Small Biofuels Project in Honduras

    Science.gov (United States)

    Ngassa, Franklin Chamda

    2010-01-01

    Biofuels may contribute to both rural economic development and climate change mitigation and adaptation. The Gota Verde Project in Yoro, Honduras, attempts to demonstrate the technical and economic feasibility of small-scale biofuel production for local use by implementing a distinctive approach to feedstock production that encourages small farm…

  7. Successional changes in trophic interactions support a mechanistic model of post-fire population dynamics.

    Science.gov (United States)

    Smith, Annabel L

    2018-01-01

    Models based on functional traits have limited power in predicting how animal populations respond to disturbance because they do not capture the range of demographic and biological factors that drive population dynamics, including variation in trophic interactions. I tested the hypothesis that successional changes in vegetation structure, which affected invertebrate abundance, would influence growth rates and body condition in the early-successional, insectivorous gecko Nephrurus stellatus. I captured geckos at 17 woodland sites spanning a succession gradient from 2 to 48 years post-fire. Body condition and growth rates were analysed as a function of the best-fitting fire-related predictor (invertebrate abundance or time since fire) with different combinations of the co-variates age, sex and location. Body condition in the whole population was positively affected by increasing invertebrate abundance and, in the adult population, this effect was most pronounced for females. There was strong support for a decline in growth rates in weight with time since fire. The results suggest that increased early-successional invertebrate abundance has filtered through to a higher trophic level with physiological benefits for insectivorous geckos. I integrated the new findings about trophic interactions into a general conceptual model of mechanisms underlying post-fire population dynamics based on a long-term research programme. The model highlights how greater food availability during early succession could drive rapid population growth by contributing to previously reported enhanced reproduction and dispersal. This study provides a framework to understand links between ecological and physiological traits underlying post-fire population dynamics.

  8. Impact of environmental colored noise in single-species population dynamics

    Science.gov (United States)

    Spanio, Tommaso; Hidalgo, Jorge; Muñoz, Miguel A.

    2017-10-01

    Variability on external conditions has important consequences for the dynamics and the organization of biological systems. In many cases, the characteristic timescale of environmental changes as well as their correlations play a fundamental role in the way living systems adapt and respond to it. A proper mathematical approach to understand population dynamics, thus, requires approaches more refined than, e.g., simple white-noise approximations. To shed further light onto this problem, in this paper we propose a unifying framework based on different analytical and numerical tools available to deal with "colored" environmental noise. In particular, we employ a "unified colored noise approximation" to map the original problem into an effective one with white noise, and then we apply a standard path integral approach to gain analytical understanding. For the sake of specificity, we present our approach using as a guideline a variation of the contact process—which can also be seen as a birth-death process of the Malthus-Verhulst class—where the propagation or birth rate varies stochastically in time. Our approach allows us to tackle in a systematic manner some of the relevant questions concerning population dynamics under environmental variability, such as determining the stationary population density, establishing the conditions under which a population may become extinct, and estimating extinction times. We focus on the emerging phase diagram and its possible phase transitions, underlying how these are affected by the presence of environmental noise time-correlations.

  9. Gradual plasticity alters population dynamics in variable environments: thermal acclimation in the green alga Chlamydomonas reinhartdii.

    Science.gov (United States)

    Kremer, Colin T; Fey, Samuel B; Arellano, Aldo A; Vasseur, David A

    2018-01-10

    Environmental variability is ubiquitous, but its effects on populations are not fully understood or predictable. Recent attention has focused on how rapid evolution can impact ecological dynamics via adaptive trait change. However, the impact of trait change arising from plastic responses has received less attention, and is often assumed to optimize performance and unfold on a separate, faster timescale than ecological dynamics. Challenging these assumptions, we propose that gradual plasticity is important for ecological dynamics, and present a study of the plastic responses of the freshwater green algae Chlamydomonas reinhardtii as it acclimates to temperature changes. First, we show that C. reinhardtii 's gradual acclimation responses can both enhance and suppress its performance after a perturbation, depending on its prior thermal history. Second, we demonstrate that where conventional approaches fail to predict the population dynamics of C. reinhardtii exposed to temperature fluctuations, a new model of gradual acclimation succeeds. Finally, using high-resolution data, we show that phytoplankton in lake ecosystems can experience thermal variation sufficient to make acclimation relevant. These results challenge prevailing assumptions about plasticity's interactions with ecological dynamics. Amidst the current emphasis on rapid evolution, it is critical that we also develop predictive methods accounting for plasticity. © 2018 The Author(s).

  10. A consumer-resource approach to the density-dependent population dynamics of mutualism.

    Science.gov (United States)

    Holland, J Nathaniel; DeAngelis, Donald L

    2010-05-01

    Like predation and competition, mutualism is now recognized as a consumer-resource (C-R) interaction, including, in particular, bi-directional (e.g., coral, plant-mycorrhizae) and uni-directional (e.g., ant-plant defense, plant-pollinator) C-R mutualisms. Here, we develop general theory for the density-dependent population dynamics of mutualism based on the C-R mechanism of interspecific interaction. To test the influence of C-R interactions on the dynamics and stability of bi- and uni-directional C-R mutualisms, we developed simple models that link consumer functional response of one mutualistic species with the resources supplied by another. Phase-plane analyses show that the ecological dynamics of C-R mutualisms are stable in general. Most transient behavior leads to an equilibrium of mutualistic coexistence, at which both species densities are greater than in the absence of interactions. However, due to the basic nature of C-R interactions, certain density-dependent conditions can lead to C-R dynamics characteristic of predator-prey interactions, in which one species overexploits and causes the other to go extinct. Consistent with empirical phenomena, these results suggest that the C-R interaction can provide a broad mechanism for understanding density-dependent population dynamics of mutualism. By unifying predation, competition, and mutualism under the common ecological framework of consumer-resource theory, we may also gain a better understanding of the universal features of interspecific interactions in general.

  11. Spiking, Bursting, and Population Dynamics in a Network of Growth Transform Neurons.

    Science.gov (United States)

    Gangopadhyay, Ahana; Chakrabartty, Shantanu

    2017-04-27

    This paper investigates the dynamical properties of a network of neurons, each of which implements an asynchronous mapping based on polynomial growth transforms. In the first part of this paper, we present a geometric approach for visualizing the dynamics of the network where each of the neurons traverses a trajectory in a dual optimization space, whereas the network itself traverses a trajectory in an equivalent primal optimization space. We show that as the network learns to solve basic classification tasks, different choices of primal-dual mapping produce unique but interpretable neural dynamics like noise shaping, spiking, and bursting. While the proposed framework is general enough, in this paper, we demonstrate its use for designing support vector machines (SVMs) that exhibit noise-shaping properties similar to those of ΣΔ modulators, and for designing SVMs that learn to encode information using spikes and bursts. It is demonstrated that the emergent switching, spiking, and burst dynamics produced by each neuron encodes its respective margin of separation from a classification hyperplane whose parameters are encoded by the network population dynamics. We believe that the proposed growth transform neuron model and the underlying geometric framework could serve as an important tool to connect well-established machine learning algorithms like SVMs to neuromorphic principles like spiking, bursting, population encoding, and noise shaping.

  12. A consumer-resource approach to the density-dependent population dynamics of mutualism

    Science.gov (United States)

    Holland, J. Nathaniel; DeAngelis, Donald L.

    2010-01-01

    Like predation and competition, mutualism is now recognized as a consumer resource (C-R) interaction, including, in particular, bi-directional (e.g., coral, plant- mycorrhizae) and uni-directional (e.g., ant-plant defense, plant-pollinator) C-R mutualisms. Here, we develop general theory for the density-dependent population dynamics of mutualism based on the C-R mechanism of interspecific interaction. To test the influence of C-R interactions on the dynamics and stability of bi- and uni-directional C-R mutualisms, we developed simple models that link consumer functional response of one mutualistic species with the resources supplied by another. Phase-plane analyses show that the ecological dynamics of C-R mutualisms are stable in general. Most transient behavior leads to an equilibrium of mutualistic coexistence, at which both species densities are greater than in the absence of interactions. However, due to the basic nature of C-R interactions, certain density-dependent conditions can lead to C-R dynamics characteristic of predator-prey interactions, in which one species overexploits and causes the other to go extinct. Consistent with empirical phenomena, these results suggest that the C-R interaction can provide a broad mechanism for understanding density-dependent population dynamics of mutualism. By unifying predation, competition, and mutualism under the common ecological framework of consumer-resource theory, we may also gain a better understanding of the universal features of interspecific interactions in general.

  13. Dynamical analysis of a model of social behavior: Criminal vs non-criminal population

    International Nuclear Information System (INIS)

    Abbas, Syed; Tripathi, Jai Prakash; Neha, A.A.

    2017-01-01

    Highlights: • A new social model of interaction between criminal and non-criminal population is proposed • The effect of law enforcement is studied • Many real life situations are analyzed • List of open problems is given for future work. - Abstract: In this paper, we construct a model motivated by the well known predator-prey model to study the interaction between criminal population and non-criminal population. Our aim is to study various possibilities of interactions between them. First we model it using simple predator-prey model, then we modify it by considering the logistic growth of non-criminal population. We clearly deduce that the model with logistic growth is better than classical one. More precisely, the role of carrying capacity on the dynamics of criminal minded population is discussed. Further, we incorporate law enforcement term in the model and study its effect. The result obtained suggest that by incorporating enforcement law, the criminal population reduces from the very beginning, which resembles with real life situation. Our result indicates that the criminal minded population exist as long as coefficient of enforcement l_c does not cross a threshold value and after this value the criminal minded population extinct. In addition, we also discuss the occurrence of saddle-node bifurcation in case of model system with law enforcement. Numerical examples and simulations are presented to illustrate the obtained results.

  14. Climate variability, human wildlife conflict and population dynamics of lions Panthera leo

    Science.gov (United States)

    Trinkel, Martina

    2013-04-01

    Large carnivores are threatened by habitat loss, declining prey populations and direct persecution. Pride dynamics of eight lion prides in the centre of the Etosha National Park, Namibia are described during a 16-year study. Since the beginning of the 1980s, the number of adult and subadult lions declined continuously to two third of its initial population size, and reached a new equilibrium in the 1990s. Pride sizes decreased from 6.3 adult females in 1989 to 2.8 lionesses in 1997. While the number of adult females declined continuously, the number of adult males, subadult females and subadult males remained constant over the years. A severe drought period, lasting for more than 20 years, led to declining prey populations inside the lions' territory. Besides declining prey populations, conflict with humans at the border of Etosha puts substantial pressure onto the lion population: 82 % of all known lion mortalities were caused by humans, and most of these consisted of adult females (28 %) and subadult males (29 %). I postulate that the considerable decline in the lion population is a response to declining prey populations, and although the human predator conflict is severe, it does not seem to limit the size of Etosha's lion population.

  15. Temporal dynamics of genetic variability in a mountain goat (Oreamnos americanus) population.

    Science.gov (United States)

    Ortego, Joaquín; Yannic, Glenn; Shafer, Aaron B A; Mainguy, Julien; Festa-Bianchet, Marco; Coltman, David W; Côté, Steeve D

    2011-04-01

    The association between population dynamics and genetic variability is of fundamental importance for both evolutionary and conservation biology. We combined long-term population monitoring and molecular genetic data from 123 offspring and their parents at 28 microsatellite loci to investigate changes in genetic diversity over 14 cohorts in a small and relatively isolated population of mountain goats (Oreamnos americanus) during a period of demographic increase. Offspring heterozygosity decreased while parental genetic similarity and inbreeding coefficients (F(IS) ) increased over the study period (1995-2008). Immigrants introduced three novel alleles into the population and matings between residents and immigrants produced more heterozygous offspring than local crosses, suggesting that immigration can increase population genetic variability. The population experienced genetic drift over the study period, reflected by a reduced allelic richness over time and an 'isolation-by-time' pattern of genetic structure. The temporal decline of individual genetic diversity despite increasing population size probably resulted from a combination of genetic drift due to small effective population size, inbreeding and insufficient counterbalancing by immigration. This study highlights the importance of long-term genetic monitoring to understand how demographic processes influence temporal changes of genetic diversity in long-lived organisms. © 2011 Blackwell Publishing Ltd.

  16. Current and Future Dynamics of the Red-Cockaded Woodpecker Population Inhabiting the Savannah River National Environmental Research Park: Managing For Population Growth

    International Nuclear Information System (INIS)

    Walters, J.R.; Taylor, T.B.; Daniels, S.J.; Crowder, L.B.; Pridd, J.A.

    2001-01-01

    Research aimed to study the dynamics of the SRS population of Red-Cockaded woodpecker and compare to those of other populations to identify factors limiting population growth; recruitment clusters were evaluated to determine what properties of individual cavity trees, surrounding habitat and the surrounding landscape might limit occupancy through natural dispersal. A spatial simulation model was used to project expected dispersal rates and population growth under current conditions and compare those estimates to observed dispersal and population growth. Red cockaded woodpecker populations at SRS are stable considering size. Research reveals that closer placement of recruitment clusters to active territories would produce higher growth rates while decreasing management intensity

  17. Current and Future Dynamics of the Red-Cockaded Woodpecker Population Inhabiting the Savannah River National Environmental Research Park: Managing For Population Growth

    Energy Technology Data Exchange (ETDEWEB)

    Walters, J.R.; Taylor, T.B.; Daniels, S.J.; Crowder, L.B.; Pridd, J.A.

    2001-01-01

    Research aimed to study the dynamics of the SRS population of Red-Cockaded woodpecker and compare to those of other populations to identify factors limiting population growth; recruitment clusters were evaluated to determine what properties of individual cavity trees, surrounding habitat and the surrounding landscape might limit occupancy through natural dispersal. A spatial simulation model was used to project expected dispersal rates and population growth under current conditions and compare those estimates to observed dispersal and population growth. Red cockaded woodpecker populations at SRS are stable considering size. Research reveals that closer placement of recruitment clusters to active territories would produce higher growth rates while decreasing management intensity.

  18. Population dynamics of excited atoms in non-Markovian environments at zero and finite temperature

    International Nuclear Information System (INIS)

    Zou Hong-Mei; Fang Mao-Fa

    2015-01-01

    The population dynamics of a two-atom system, which is in two independent Lorentzian reservoirs or in two independent Ohmic reservoirs respectively, where the reservoirs are at zero temperature or finite temperature, is studied by using the time-convolutionless master-equation method. The influences of the characteristics and temperature of a non-Markovian environment on the population of the excited atoms are analyzed. We find that the population trapping of the excited atoms is related to the characteristics and the temperature of the non-Markovian environment. The results show that, at zero temperature, the two atoms can be effectively trapped in the excited state both in the Lorentzian reservoirs and in the Ohmic reservoirs. At finite temperature, the population of the excited atoms will quickly decay to a nonzero value. (paper)

  19. Dynamical networks: Finding, measuring, and tracking neural population activity using network science

    Directory of Open Access Journals (Sweden)

    Mark D. Humphries

    2017-12-01

    Full Text Available Systems neuroscience is in a headlong rush to record from as many neurons at the same time as possible. As the brain computes and codes using neuron populations, it is hoped these data will uncover the fundamentals of neural computation. But with hundreds, thousands, or more simultaneously recorded neurons come the inescapable problems of visualizing, describing, and quantifying their interactions. Here I argue that network science provides a set of scalable, analytical tools that already solve these problems. By treating neurons as nodes and their interactions as links, a single network can visualize and describe an arbitrarily large recording. I show that with this description we can quantify the effects of manipulating a neural circuit, track changes in population dynamics over time, and quantitatively define theoretical concepts of neural populations such as cell assemblies. Using network science as a core part of analyzing population recordings will thus provide both qualitative and quantitative advances to our understanding of neural computation.

  20. Dynamics of genetic processes in chronically irradiated populations of small mammals

    International Nuclear Information System (INIS)

    Ryabokon', N.I.; Goncharova, R.I.; Smolich, I.I.; Kapitanova, N.P.; Nikitchenko, N.V.

    2000-01-01

    The distinctive features of dynamics of mutagenesis in mammalian populations under chronic low-intensive irradiation were first revealed. The main of them is gradual increase in mutability in somatic cells and embryonal lethality during series of irradiated generations of animals (bank vole - Clethrionomys glareolus). The data obtained strongly suggest that there are oppositely directed processes in natural populations after irradiation of more than 20 generations of animals: on the one hand, accumulation of mutations (genetic load of populations) and pre-mutation events which increase genome instability of germ and somatic cells in consecutive generations of animals, and on the other, formation of genetic radio adaptation through better functioning protection systems. In this period of micro evolution in chronically irradiated populations, the frequencies of genetic damages could be higher if the radiation adaptation doesn't form. (authors)

  1. A scoping review and prevalence analysis of soil-transmitted helminth infections in Honduras.

    Directory of Open Access Journals (Sweden)

    Ana Lourdes Sanchez

    Full Text Available Honduras is endemic for soil-transmitted helminth (STH infections, but critical information gaps still remain on the prevalence and intensity of these infections as well as on their spatial distribution at subnational levels.Firstly, to review the research activity on STH infections in Honduras and secondly, to carry out a national prevalence analysis and map the geographical distribution of these infections in children.A systematic search was conducted of the published and grey literature to identify scientific work on the impact and prevalence of STH infections done between May 1930 and June 30, 2012. International databases and Honduran journals were searched. Grey literature was gleaned from local libraries and key informants. Select studies conducted between 2001 and 2012 were used to produce prevalence maps and to investigate association between STH prevalence and socio-economic and environmental factors.Of 257 identified studies, 211 (21.4% peer-reviewed were retained for analysis and categorized as clinical research (10.9%, treatment efficacy studies (8.1% or epidemiological studies (81%. Prevalence analysis and geographical mapping included 36 epidemiological studies from Honduras's 18 departments and 23% of its municipalities. Overall STH prevalence was >50% in 40.6% of municipalities. Prevalences above 20% for each trichuriasis, ascariasis, and hookworm infection were found in 68%, 47.8%, and 7.2% of studied municipalities, respectively. Municipalities with lower human development index, less access to of potable water, and with higher annual precipitation showed higher STH prevalences.This is the first study to provide a comprehensive historic review of STH research activity and prevalence in Honduras, revealing important knowledge gaps related to infection risk factors, disease burden, and anti-parasitic drug efficacy, among others. Our decade-long prevalence analysis reveals geographical differences in STH prevalence and these

  2. Post-introduction economic evaluation of pneumococcal conjugate vaccination in Ecuador, Honduras, and Paraguay

    Directory of Open Access Journals (Sweden)

    Dagna O. Constenla

    Full Text Available OBJECTIVE:A decision-analytic model was constructed to evaluate the economic impact of post-introduction pneumococcal conjugate vaccine (PCV programs in Ecuador, Honduras, and Paraguay from the societal perspective. METHODS: Hypothetical birth cohorts were followed for a 20-year period in each country. Estimates of disease burden, vaccine effectiveness, and health care costs were derived from primary and secondary data sources. Costs were expressed in 2014 US$. Sensitivity analyses were performed to assess the impact of model input uncertainties. RESULTS: Over the 20 years of vaccine program implementation, the health care costs per case ranged from US$ 764 854 to more than US$ 1 million. Vaccination prevented more than 50% of pneumococcal cases and deaths per country. At a cost of US$ 16 per dose, the cost per disability-adjusted life year (DALY averted for the 10-valent PCV (PCV10 and the 13-valet PCV (PCV13 ranged from US$ 796 (Honduras to US$ 1 340 (Ecuador and from US$ 691 (Honduras to US$ 1 166 (Ecuador respectively. At a reduced price (US$ 7 per dose, the cost per DALY averted ranged from US$ 327 (Honduras to US$ 528 (Ecuador and from US$ 281 (Honduras to US$ 456 (Ecuador for PCV10 and PCV13 respectively. Several model parameters influenced the results of the analysis, including vaccine price, vaccine efficacy, disease incidence, and costs. CONCLUSIONS: The economic impact of post-introduction PCV needs to be assessed in a context of uncertainty regarding changing antibiotic resistance, herd and serotype replacement effects, differential vaccine prices, and government budget constraints.

  3. Drug resistance associated genetic polymorphisms in Plasmodium falciparum and Plasmodium vivax collected in Honduras, Central America.

    Science.gov (United States)

    Jovel, Irina T; Mejía, Rosa E; Banegas, Engels; Piedade, Rita; Alger, Jackeline; Fontecha, Gustavo; Ferreira, Pedro E; Veiga, Maria I; Enamorado, Irma G; Bjorkman, Anders; Ursing, Johan

    2011-12-19

    In Honduras, chloroquine and primaquine are recommended and still appear to be effective for treatment of Plasmodium falciparum and Plasmodium vivax malaria. The aim of this study was to determine the proportion of resistance associated genetic polymorphisms in P. falciparum and P. vivax collected in Honduras. Blood samples were collected from patients seeking medical attention at the Hospital Escuela in Tegucigalpa from 2004 to 2006 as well as three regional hospitals, two health centres and one regional laboratory during 2009. Single nucleotide polymorphisms in P. falciparum chloroquine resistance transporter (pfcrt), multidrug resistance 1 (pfmdr1), dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes and in P. vivax multidrug resistance 1 (pvmdr1) and dihydrofolate reductase (pvdhfr) genes were detected using PCR based methods. Thirty seven P. falciparum and 64 P. vivax samples were collected. All P. falciparum infections acquired in Honduras carried pfcrt, pfmdr1, pfdhps and pfdhfr alleles associated with chloroquine, amodiaquine and sulphadoxine-pyrimethamine sensitivity only. One patient with parasites acquired on a Pacific Island had pfcrt 76 T and pfmdr1 86Y alleles. That patient and a patient infected in West Africa had pfdhfr 51I, 59 R and 108 N alleles. Pvmdr1 976 F was found in 7/37 and two copies of pvmdr1 were found in 1/37 samples. Pvdhfr 57 L + 58 R was observed in 2/57 samples. The results indicate that P. falciparum from Honduras remain sensitive to chloroquine and sulphadoxine-pyrimethamine. This suggests that chloroquine and sulphadoxine-pyrimethamine should be efficacious for treatment of uncomplicated P. falciparum malaria, supporting current national treatment guidelines. However, genetic polymorphisms associated with chloroquine and sulphadoxine-pyrimethamine tolerance were detected in local P. vivax and imported P. falciparum infections. Continuous monitoring of the prevalence of drug resistant/tolerant P

  4. A scoping review and prevalence analysis of soil-transmitted helminth infections in Honduras.

    Science.gov (United States)

    Sanchez, Ana Lourdes; Gabrie, José Antonio; Rueda, María Mercedes; Mejia, Rosa Elena; Bottazzi, Maria Elena; Canales, Maritza

    2014-01-01

    Honduras is endemic for soil-transmitted helminth (STH) infections, but critical information gaps still remain on the prevalence and intensity of these infections as well as on their spatial distribution at subnational levels. Firstly, to review the research activity on STH infections in Honduras and secondly, to carry out a national prevalence analysis and map the geographical distribution of these infections in children. A systematic search was conducted of the published and grey literature to identify scientific work on the impact and prevalence of STH infections done between May 1930 and June 30, 2012. International databases and Honduran journals were searched. Grey literature was gleaned from local libraries and key informants. Select studies conducted between 2001 and 2012 were used to produce prevalence maps and to investigate association between STH prevalence and socio-economic and environmental factors. Of 257 identified studies, 211 (21.4% peer-reviewed) were retained for analysis and categorized as clinical research (10.9%), treatment efficacy studies (8.1%) or epidemiological studies (81%). Prevalence analysis and geographical mapping included 36 epidemiological studies from Honduras's 18 departments and 23% of its municipalities. Overall STH prevalence was >50% in 40.6% of municipalities. Prevalences above 20% for each trichuriasis, ascariasis, and hookworm infection were found in 68%, 47.8%, and 7.2% of studied municipalities, respectively. Municipalities with lower human development index, less access to of potable water, and with higher annual precipitation showed higher STH prevalences. This is the first study to provide a comprehensive historic review of STH research activity and prevalence in Honduras, revealing important knowledge gaps related to infection risk factors, disease burden, and anti-parasitic drug efficacy, among others. Our decade-long prevalence analysis reveals geographical differences in STH prevalence and these findings

  5. Post-introduction economic evaluation of pneumococcal conjugate vaccination in Ecuador, Honduras, and Paraguay.

    Science.gov (United States)

    Constenla, Dagna O

    2015-11-01

    A decision-analytic model was constructed to evaluate the economic impact of post-introduction pneumococcal conjugate vaccine (PCV) programs in Ecuador, Honduras, and Paraguay from the societal perspective. Hypothetical birth cohorts were followed for a 20-year period in each country. Estimates of disease burden, vaccine effectiveness, and health care costs were derived from primary and secondary data sources. Costs were expressed in 2014 US$. Sensitivity analyses were performed to assess the impact of model input uncertainties. Over the 20 years of vaccine program implementation, the health care costs per case ranged from US$ 764 854 to more than US$ 1 million. Vaccination prevented more than 50% of pneumococcal cases and deaths per country. At a cost of US$ 16 per dose, the cost per disability-adjusted life year (DALY) averted for the 10-valent PCV (PCV10) and the 13-valet PCV (PCV13) ranged from US$ 796 (Honduras) to US$ 1 340 (Ecuador) and from US$ 691 (Honduras) to US$ 1 166 (Ecuador) respectively. At a reduced price (US$ 7 per dose), the cost per DALY averted ranged from US$ 327 (Honduras) to US$ 528 (Ecuador) and from US$ 281 (Honduras) to US$ 456 (Ecuador) for PCV10 and PCV13 respectively. Several model parameters influenced the results of the analysis, including vaccine price, vaccine efficacy, disease incidence, and costs. The economic impact of post-introduction PCV needs to be assessed in a context of uncertainty regarding changing antibiotic resistance, herd and serotype replacement effects, differential vaccine prices, and government budget constraints.

  6. Stand development and population dynamics of curlleaf mountain mahogany (Cercocarpus ledifolius Nutt.) woodlands in Utah's Bear River Mountains

    Science.gov (United States)

    Seth A. Ex; Robert DeRose; James N. Long

    2011-01-01

    Curlleaf mountain mahogany (Cercocarpus ledifolius Nutt.) is a little-studied woodland tree that occurs in pure stands throughout the Intermountain West. Stand development and population dynamics of this species are poorly understood, despite their relevance to management. We describe here the development of stand age structures and population dynamics of mahogany...

  7. Turkey’s Population Dynamics As A Candidate Country For EU Membership

    Directory of Open Access Journals (Sweden)

    Harun Uçak

    2011-01-01

    Full Text Available Literally, it has been accepted that one of the major obstacles to Turkey’s EU membership is in population term. There has not been any enlargement process as large as Turkey’s population as a single state in EU history before. The enlargement in 2004 which includes 10 states involved 74 million people as whole member states while Turkey’s population is 72 million inhabitants in 2007 data which is only lower than Germany’s population in all EU member states. Thus, Turkey's accession would be different from previous enlargements because of the combined impact of high population. This study compares the population dynamics, working conditions, minimum wage rates and main macroeconomic indicators between Turkey and EU member states. Turkey has young generations compared to EU countries. In the comparison of age groups proportion in total population, 0-19 age group %21,9 in EU 27 and %36,5 in Turkey, 20-39 age group is %28 in EU 27 and %34,3 in Turkey, 40-59 age group is %27,9 in EU and %20,9 in Turkey, 60 and above age group is %22,1 in EU and %9,5 in Turkey. Thus, population dynamics of Turkey could make a contribution to offsetting the ageing of EU 27 societies if the membership would occur in the future. However, minimum wage rates in Turkey are lower than many EU member states but generally higher than EU member states located in Central and Eastern Europe. Thus, immigration possibilities from Turkey can be expected to Western European Countries, but not the same direction to Central and Eastern Europe Countries. Furthermore, the process in macroeconomic indicators will be a determinant in immigration expectations while Turkey’s GDP has been grown faster than EU level recently.

  8. Heat exposure in cities: combining the dynamics of temperature and population

    Science.gov (United States)

    Hu, L.; Wilhelmi, O.; Uejio, C. K.

    2017-12-01

    Assessment of human exposure to extreme heat requires the distributions of temperature and population. However, both variables are dynamic, thus presenting many challenges in capturing temperature and population patterns spatially and over time in an urban context. This study aims to improve the understanding of spatiotemporal patterns of urban population exposure to heat, taking Chicago, USA as an example. We estimate the hourly, geographically variable, population distribution considering commute of workers and students in a regular weekday and analyze the diurnal air temperature patterns during different meteorological conditions from satellite observations. The results show a relatively larger temperature increase in less urbanized areas during extreme heat events (EHEs), resulting in a spatially homogeneous temperature distribution over Chicago Metropolitan area. A lake cooling effect is weaker during EHEs. Population dynamics due to daily commute determine higher population density in more urbanized areas during daytime. The city-wide analysis reveals that the exposure is more sensitive to the nighttime temperature increases, and EHEs enhance this sensitivity. The high exposure hotspots are identified at the northwest Chicago, Cicero and Oak Park areas, where the influence from Lake Michigan is weakened, while the spatial extent of high outdoor exposure areas varies diurnally. This study's findings have potential to better inform general heat mitigation strategies during hot summer months and facilitate emergency response during EHEs. Availability of remotely-sensed temperature observations as well as the workers and students commute-adjusted population data allows for the adoption of this study's methodology in other major metropolitan areas. A better understanding of space-time patterns of urban population's exposure to heat will further enable local decision makers to mitigate extreme heat health risks and develop more targeted heat preparedness and

  9. Climate, invasive species and land use drive population dynamics of a cold-water specialist

    Science.gov (United States)

    Kovach, Ryan P.; Al-Chokhachy, Robert K.; Whited, Diane C.; Schmetterling, David A.; Dux, Andrew M; Muhlfeld, Clint C.

    2017-01-01

    Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold-water fishes. Research addressing the consequences of climate change on cold-water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences population dynamics in the context of other existing stressors.We used long-term data from 92 populations of bull trout Salvelinus confluentus – one of North America's most cold-adapted fishes – to quantify additive and interactive effects of climate, invasive species and land use on population dynamics (abundance, variability and growth rate).Populations were generally depressed, more variable and declining where spawning and rearing stream habitat was limited, invasive species and land use were prevalent and stream temperatures were highest. Increasing stream temperature acted additively and independently, whereas land use and invasive species had additive and interactive effects (i.e. the impact of one stressor depended on exposure to the other stressor).Most (58%–78%) of the explained variation in population dynamics was attributed to the presence of invasive species, differences in life history and management actions in foraging habitats in rivers, lakes and reservoirs. Although invasive fishes had strong negative effects on populations in foraging habitats, proactive control programmes appeared to effectively temper their negative impact.Synthesis and applications. Long-term demographic data emphasize that climate warming will exacerbate imperilment of cold-water specialists like bull trout, yet other stressors – especially invasive fishes – are immediate threats that can be addressed by proactive management actions. Therefore, climate-adaptation strategies for freshwater biodiversity should consider existing abiotic and biotic stressors, some of which provide potential and realized opportunity for conservation

  10. Hydrogeochemical investigation of six geothermal sites in Honduras, Central America

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.E.; Truesdell, A.H.; Grigsby, C.O.; Janik, C.J.; Shevenell, L.A.; Paredes, J.R.; Gutierrez, J.W.; Trujillo, Jr.; Counce, D.A.

    1987-06-01

    We conducted detailed hydrogeochemical investigations at six geothermal sites in western Honduras: Azacualpa, El Olivar, Pavana, Platanares, Sambo Creek, and San Ignacio. None of the sites is associated with Quaternary silicic volcanism, although El Olivar lies adjacent to a small Quaternary basalt field and Pavana is part of a belt of hot spring activity parallel to and 35 km east of the Central American volcanic arc. None of the sites contains acid-sulfate waters indicative of vapor-dominated conditions. Thermal fluids are characterized by pH between 7 and 10, Cl<125 mg/l, HCO/sub 3/>Cl, SO/sub 4/greater than or equal toCl, Bless than or equal to17 mg/l, Liless than or equal to4 mg/l, and Asless than or equal to1.25 mg/l. Stable isotope analyses of the water show that recharge to the geothermal systems generally occurs from areas of higher elevation adjacent to the sites. Tritium contents of apparently undiluted thermal fluids range from 0 to 0.4 T.U., indicating residence times of fluids in the systems of more than 500 y. Various geochemical indicators show that mixing of hot and cold end-member fluids occurs in the system at Platanares and, to a lesser degree, in the systems at San Ignacio and Azacualpa. No mixing is apparent in the fluids discharging at Pavana, Sambo Creek, or El Olivar. Boiling is the dominant process responsible for subtle geochemical variations at Azacualpa and, possibly, San Ignacio. Our best estimates of subsurface reservoir temperatures are 225/sup 0/C at Platanares, 190/sup 0/C at San Ignacio, 185/sup 0/C at Azacualpa, 155/sup 0/C at Sambo Creek, 150/sup 0/C at Pavana, and 120/sup 0/C at El Olivar. The estimated power output of the three hottest sites is 45 thermal megawatts at Platanares, 14 thermal megawatts at San Ignacio, and 13 thermal megawatts at Azacualpa.

  11. Scaling of the mean and variance of population dynamics under fluctuating regimes.

    Science.gov (United States)

    Pertoldi, Cino; Faurby, S; Reed, D H; Knape, J; Björklund, M; Lundberg, P; Kaitala, V; Loeschcke, V; Bach, L A

    2014-12-01

    Theoretical ecologists have long sought to understand how the persistence of populations depends on the interactions between exogenous (biotic and abiotic) and endogenous (e.g., demographic and genetic) drivers of population dynamics. Recent work focuses on the autocorrelation structure of environmental perturbations and its effects on the persistence of populations. Accurate estimation of extinction times and especially determination of the mechanisms affecting extinction times is important for biodiversity conservation. Here we examine the interaction between environmental fluctuations and the scaling effect of the mean population size with its variance. We investigate how interactions between environmental and demographic stochasticity can affect the mean time to extinction, change optimal patch size dynamics, and how it can alter the often-assumed linear relationship between the census size and the effective population size. The importance of the correlation between environmental and demographic variation depends on the relative importance of the two types of variation. We found the correlation to be important when the two types of variation were approximately equal; however, the importance of the correlation diminishes as one source of variation dominates. The implications of these findings are discussed from a conservation and eco-evolutionary point of view.

  12. Factors affecting population dynamics of maternally transmitted endosymbionts in Bemisia tabaci.

    Directory of Open Access Journals (Sweden)

    Huipeng Pan

    Full Text Available While every individual of Bemisia tabaci (Hemiptera: Aleyrodidae harbors the primary symbiont (P-symbiont Portiera, the infection frequencies of the six secondary symbionts (S-symbionts including Hamiltonella, Arsenophonus, Cardinium, Wolbachia, Rickettsia and Fritschea vary greatly among different populations. To characterize the factors influencing the infection dynamics of the six S-symbionts in B. tabaci, gene-specific PCR were conducted to screen for the presence of the P-symbiont Portiera and the six S-symbionts in 61 (17 B and 44 Q biotypes field populations collected from different plant species and locations in China. All individuals of the 61 populations hosted the P-symbiont Portiera, but none of them harbored Arsenophonus and Fritschea. The presence and infection rates of Hamiltonella, Cardinium, Rickettsia, Wolbachia and their co-infections Rickettsia + Hamiltonella (RH, Rickettsia + Cardinium (RC, Hamiltonella + Cardinium (HC and Rickettsia + Hamiltonella + Cardinium (RHC varied significantly among the 61 field populations; and the observed variations can be explained by biotypes, sexes, host plants and geographical locations of these field populations. Taken together, at least three factors including biotype, host plant and geographical location affect the infection dynamics of S-symbionts in B. tabaci.

  13. Alleles versus genotypes: Genetic interactions and the dynamics of selection in sexual populations

    Science.gov (United States)

    Neher, Richard

    2010-03-01

    Physical interactions between amino-acids are essential for protein structure and activity, while protein-protein interactions and regulatory interactions are central to cellular function. As a consequence of these interactions, the combined effect of two mutations can differ from the sum of the individual effects of the mutations. This phenomenon of genetic interaction is known as epistasis. However, the importance of epistasis and its effects on evolutionary dynamics are poorly understood, especially in sexual populations where recombination breaks up existing combinations of alleles to produce new ones. Here, we present a computational model of selection dynamics involving many epistatic loci in a recombining population. We demonstrate that a large number of polymorphic interacting loci can, despite frequent recombination, exhibit cooperative behavior that locks alleles into favorable genotypes leading to a population consisting of a set of competing clones. As the recombination rate exceeds a certain critical value this ``genotype selection'' phase disappears in an abrupt transition giving way to ``allele selection'' - the phase where different loci are only weakly correlated as expected in sexually reproducing populations. Clustering of interacting sets of genes on a chromosome leads to the emergence of an intermediate regime, where localized blocks of cooperating alleles lock into genetic modules. Large populations attain highest fitness at a recombination rate just below critical, suggesting that natural selection might tune recombination rates to balance the beneficial aspect of exploration of genotype space with the breaking up of synergistic allele combinations.

  14. Dynamics of sexual populations structured by a space variable and a phenotypical trait

    KAUST Repository

    Mirrahimi, Sepideh

    2013-03-01

    We study sexual populations structured by a phenotypic trait and a space variable, in a non-homogeneous environment. Departing from an infinitesimal model, we perform an asymptotic limit to derive the system introduced in Kirkpatrick and Barton (1997). We then perform a further simplification to obtain a simple model. Thanks to this simpler equation, we can describe rigorously the dynamics of the population. In particular, we provide an explicit estimate of the invasion speed, or extinction speed of the species. Numerical computations show that this simple model provides a good approximation of the original infinitesimal model, and in particular describes quite well the evolution of the species\\' range. © 2013 Elsevier Inc.

  15. Dynamics of sexual populations structured by a space variable and a phenotypical trait

    KAUST Repository

    Mirrahimi, Sepideh; Raoul, Gaë l

    2013-01-01

    We study sexual populations structured by a phenotypic trait and a space variable, in a non-homogeneous environment. Departing from an infinitesimal model, we perform an asymptotic limit to derive the system introduced in Kirkpatrick and Barton (1997). We then perform a further simplification to obtain a simple model. Thanks to this simpler equation, we can describe rigorously the dynamics of the population. In particular, we provide an explicit estimate of the invasion speed, or extinction speed of the species. Numerical computations show that this simple model provides a good approximation of the original infinitesimal model, and in particular describes quite well the evolution of the species' range. © 2013 Elsevier Inc.

  16. On Oscillatory Pattern of Malaria Dynamics in a Population with Temporary Immunity

    Directory of Open Access Journals (Sweden)

    J. Tumwiine

    2007-01-01

    Full Text Available We use a model to study the dynamics of malaria in the human and mosquito population to explain the stability patterns of malaria. The model results show that the disease-free equilibrium is globally asymptotically stable and occurs whenever the basic reproduction number, R0 is less than unity. We also note that when R0>1, the disease-free equilibrium is unstable and the endemic equilibrium is stable. Numerical simulations show that recoveries and temporary immunity keep the populations at oscillation patterns and eventually converge to a steady state.

  17. Dynamic of age structure and the number of population in Ozyorsk and affecting factors

    International Nuclear Information System (INIS)

    Panchenko, O.; Rtischeva, M.

    2001-01-01

    In connection with serious social-economic and ecological problems in our country an analysis of demographic processes in cities of atomic industry causes a big of interest. The aim of this work was an evaluation of dynamic of age structure of population of city Ozyorsk, based in connection with creation of nuclear plant 'Mayak' of 'first-born' of atomic industry in Russia. Data received in city's administration, included the information about number of population, its age composition taking into account of natural increase and of migration processes for a period from 1959 to 1997. (authors)

  18. Burden of diarrhea among children in Honduras, 2000-2004: estimates of the role of rotavirus La diarrea infantil en Honduras, 2000-2004: estimados del papel desempeñado por el rotavirus

    OpenAIRE

    José Orlando Solórzano Girón; Ida Berenice Molina; Reina M. Turcios-Ruiz; Claudia E. Quiroz Mejia; Luis Miguel Amendola; Lucia Helena de Oliveira; Jon K. Andrus; Paul W. Stupp; Joseph S. Bresee; Roger I. Glass

    2006-01-01

    OBJECTIVES: To estimate the annual burden of diarrhea and of diarrhea that is associated with rotavirus (RV) in children who are treated at public clinics and hospitals in Honduras. METHODS: Data were collected from computerized records of all children < 5 years old treated for diarrhea at clinics and hospitals operated by the Secretary of Health for the period of 2000 through 2004. A review of studies of RV in Honduras and neighboring countries provided estimates of detection rates of RV amo...

  19. Phenotypic equilibrium as probabilistic convergence in multi-phenotype cell population dynamics.

    Directory of Open Access Journals (Sweden)

    Da-Quan Jiang

    Full Text Available We consider the cell population dynamics with n different phenotypes. Both the Markovian branching process model (stochastic model and the ordinary differential equation (ODE system model (deterministic model are presented, and exploited to investigate the dynamics of the phenotypic proportions. We will prove that in both models, these proportions will tend to constants regardless of initial population states ("phenotypic equilibrium" under weak conditions, which explains the experimental phenomenon in Gupta et al.'s paper. We also prove that Gupta et al.'s explanation is the ODE model under a special assumption. As an application, we will give sufficient and necessary conditions under which the proportion of one phenotype tends to 0 (die out or 1 (dominate. We also extend our results to non-Markovian cases.

  20. Experimental evolution and the dynamics of adaptation and genome evolution in microbial populations.

    Science.gov (United States)

    Lenski, Richard E

    2017-10-01

    Evolution is an on-going process, and it can be studied experimentally in organisms with rapid generations. My team has maintained 12 populations of Escherichia coli in a simple laboratory environment for >25 years and 60 000 generations. We have quantified the dynamics of adaptation by natural selection, seen some of the populations diverge into stably coexisting ecotypes, described changes in the bacteria's mutation rate, observed the new ability to exploit a previously untapped carbon source, characterized the dynamics of genome evolution and used parallel evolution to identify the genetic targets of selection. I discuss what the future might hold for this particular experiment, briefly highlight some other microbial evolution experiments and suggest how the fields of experimental evolution and microbial ecology might intersect going forward.