WorldWideScience

Sample records for explains distribution patterns

  1. Historical dynamics and current environmental effects explain the spatial distribution of species richness patterns of New World monkeys

    Directory of Open Access Journals (Sweden)

    Paulo Vallejos-Garrido

    2017-09-01

    -fitting model that explains species richness. OLS and SAR models show that this set of variables explains 69.9% and 64.2% of species richness, respectively. Potential of evapotranspiration is the most important variable within this model, showing a linear positive relationship with species richness, and clear lower and upper limits to the species richness distribution. Discussion We suggest that New World monkeys historically migrated from their biodiversity hotspot (energetically optimal areas for most platyrrine species to adjacent, energetically suboptimal areas, and that the different dispersal abilities of these species, the lack of competitive interactions at a macroecological scale, and environmental constraints (i.e., energy availability, seasonality are key elements which explain the non-uniform pattern of species richness for this clade.

  2. Climate and landscape explain richness patterns depending on the type of species' distribution data

    Science.gov (United States)

    Tsianou, Mariana A.; Koutsias, Nikolaos; Mazaris, Antonios D.; Kallimanis, Athanasios S.

    2016-07-01

    Understanding the patterns of species richness and their environmental drivers, remains a central theme in ecological research and especially in the continental scales where many conservation decisions are made. Here, we analyzed the patterns of species richness from amphibians, reptiles and mammals at the EU level. We used two different data sources for each taxon: expert-drawn species range maps, and presence/absence atlases. As environmental drivers, we considered climate and land cover. Land cover is increasingly the focus of research, but there still is no consensus on how to classify land cover to distinct habitat classes, so we analyzed the CORINE land cover data with three different levels of thematic resolution (resolution of classification scheme ˗ less to more detailed). We found that the two types of species richness data explored in this study yielded different richness maps. Although, we expected expert-drawn range based estimates of species richness to exceed those from atlas data (due to the assumption that species are present in all locations throughout their region), we found that in many cases the opposite is true (the extreme case is the reptiles where more than half of the atlas based estimates were greater than the expert-drawn range based estimates). Also, we detected contrasting information on the richness drivers of biodiversity patterns depending on the dataset used. For atlas based richness estimates, landscape attributes played more important role than climate while for expert-drawn range based richness estimates climatic variables were more important (for the ectothermic amphibians and reptiles). Finally we found that the thematic resolution of the land cover classification scheme, also played a role in quantifying the effect of land cover diversity, with more detailed thematic resolution increasing the relative contribution of landscape attributes in predicting species richness.

  3. Intermittent Plurisink Model and the Emergence of Complex Heterogeneity Patterns: A Simple Paradigm for Explaining Complexity in Soil Chemical Distributions

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Martín

    2015-01-01

    Full Text Available The spatial complexity of the distribution of organic matter, chemicals, nutrients, and pollutants has been demonstrated to have multifractal nature. This fact supports the possibility of existence of some emergent heterogeneity structure built under the evolution of the system. The aim of this paper is providing a consistent explanation of the mentioned results via an extremely simple model.

  4. Localized bedrock aquifer distribution explains discharge from a headwater catchment

    Science.gov (United States)

    Kosugi, Ken'ichirou; Fujimoto, Masamitsu; Katsura, Shin'ya; Kato, Hiroyuki; Sando, Yoshiki; Mizuyama, Takahisa

    2011-07-01

    Understanding a discharge hydrograph is one of the leading interests in catchment hydrology. Recent research has provided credible information on the importance of bedrock groundwater on discharge hydrographs from headwater catchments. However, intensive monitoring of bedrock groundwater is rare in mountains with steep topography. Hence, how bedrock groundwater controls discharge from a steep headwater catchment is in dispute. In this study, we conducted long-term hydrological observations using densely located bedrock wells in a headwater catchment underlain by granitic bedrock. The catchment has steep topography affected by diastrophic activities. Results showed a fairly regionalized distribution of bedrock aquifers within a scale of tens of meters, consisting of upper, middle, and lower aquifers, instead of a gradual and continuous decline in water level from ridge to valley bottom. This was presumably attributable to the unique bedrock structure; fault lines developed in the watershed worked to form divides between the bedrock aquifers. Spatial expanse of each aquifer and the interaction among aquifers were key factors to explain gentle and considerable variations in the base flow discharge and triple-peak discharge responses of the observed hydrograph. A simple model was developed to simulate the discharge hydrograph, which computed each of the contributions from the soil mantle groundwater, from the lower aquifer, and from the middle aquifer to the discharge. The modeling results generally succeeded in reproducing the observed hydrograph. Thus, this study demonstrated that understanding regionalized bedrock aquifer distribution is pivotal for explaining discharge hydrograph from headwater catchments that have been affected by diastrophic activities.

  5. Explaining the power-law distribution of human mobility through transportation modality decomposition.

    Science.gov (United States)

    Zhao, Kai; Musolesi, Mirco; Hui, Pan; Rao, Weixiong; Tarkoma, Sasu

    2015-03-16

    Human mobility has been empirically observed to exhibit Lévy flight characteristics and behaviour with power-law distributed jump size. The fundamental mechanisms behind this behaviour has not yet been fully explained. In this paper, we propose to explain the Lévy walk behaviour observed in human mobility patterns by decomposing them into different classes according to the different transportation modes, such as Walk/Run, Bike, Train/Subway or Car/Taxi/Bus. Our analysis is based on two real-life GPS datasets containing approximately 10 and 20 million GPS samples with transportation mode information. We show that human mobility can be modelled as a mixture of different transportation modes, and that these single movement patterns can be approximated by a lognormal distribution rather than a power-law distribution. Then, we demonstrate that the mixture of the decomposed lognormal flight distributions associated with each modality is a power-law distribution, providing an explanation to the emergence of Lévy Walk patterns that characterize human mobility patterns.

  6. Predator identity can explain nest predation patterns. Chapter 11

    Science.gov (United States)

    Jennifer L. Reidy; Frank R., III Thompson

    2012-01-01

    Knowledge of dominant predators is necessary to identify predation patterns and mitigate losses to nest predation, especially for endangered songbirds. We monitored songbird nests with timelapse infrared video cameras at Fort Hood Military Reservation, Texas, from 1997 to 2002 and 2005, and in Austin, Texas, during 2005, 2006, 2008, and 2009. Predation was the most...

  7. Can evolutionary principles explain patterns of family violence?

    Science.gov (United States)

    Archer, John

    2013-03-01

    The article's aim is to evaluate the application of the evolutionary principles of kin selection, reproductive value, and resource holding power to the understanding of family violence. The principles are described in relation to specific predictions and the mechanisms underlying these. Predictions are evaluated for physical violence perpetrated by (a) parents to unrelated children, (b) parents to genetic offspring, and (c) offspring to parents and between (d) siblings and (e) sexual partners. Precise figures for risks have been calculated where possible. The major conclusions are that most of the evidence is consistent with evolutionary predictions derived from kin selection and reproductive value: There were (a) higher rates of violence to stepchildren, (b) a decline in violence with the age of offspring, and (c) an increase in violence with parental age, while (d) violence between siblings was generally at a low level and concerned resource disputes. The issue of distinguishing evolutionary from alternative explanations is addressed throughout and is problematic for predictions derived from reproductive value. The main evolutionary explanation for male partner violence, mate guarding as a result of paternity uncertainty, cannot explain Western studies where sex differences in control and violence between partners were absent, although other aspects of male partner violence are consistent with it, and it may explain sex differences in traditional cultures. Recurrent problems in evaluating the evidence were to control for possible confounds and thus to distinguish evolutionary from alternative explanations. Suggestions are outlined to address this and other issues arising from the review. © 2013 American Psychological Association

  8. Who intermarries in Britain? Explaining ethnic diversity in intermarriage patterns.

    Science.gov (United States)

    Muttarak, Raya; Heath, Anthony

    2010-06-01

    This paper investigates trends, patterns and determinants of intermarriage (and partnership) comparing patterns among men and women and among different ethnic groups in Britain. We distinguish between endogamous (co-ethnic), majority/minority and minority/minority marriages. Hypotheses are derived from the theoretical literatures on assimilation, segmented assimilation and opportunity structures. The empirical analysis is based on the 1988-2006 General Household Surveys (N = 115,494). Consistent with assimilation theory we find that, for all ethnic minority groups, the propensity to intermarry is higher in the second generation than in the first. Consistent with ideas drawn from segmented assimilation theory, we also find that substantial differences in propensity to form majority/minority marriages persist after controls for individual characteristics such as age, educational level, generation and length of residence in Britain, with men and women of Indian, Pakistani or Bangladeshi background having higher propensities to form endogamous partnerships. However, we also find that opportunity structures affect intermarriage propensities for all groups alike, with individuals in more diverse residential areas (as measured by the ratio of majority to minority residents in the area) having higher likelihood to form majority/minority partnerships. We conclude then that, beginning from very different starting points, all groups, both minority and the majority groups exhibit common patterns of generational change and response to opportunity structures. Even the groups that are believed to have the strongest community structures and the strongest norms supporting endogamy appear to be experiencing increasing exogamy in the second generation and in more diverse residential settings. This suggests that a weak rather than a strong version of segmented assimilation provides the best account of British patterns.

  9. Disentangling vegetation diversity from climate–energy and habitat heterogeneity for explaining animal geographic patterns

    Science.gov (United States)

    Jimenez-Alfaro, Borja; Chytry, Milan; Mucina, Ladislav; Grace, James B.; Rejmanek, Marcel

    2016-01-01

    Broad-scale animal diversity patterns have been traditionally explained by hypotheses focused on climate–energy and habitat heterogeneity, without considering the direct influence of vegetation structure and composition. However, integrating these factors when considering plant–animal correlates still poses a major challenge because plant communities are controlled by abiotic factors that may, at the same time, influence animal distributions. By testing whether the number and variation of plant community types in Europe explain country-level diversity in six animal groups, we propose a conceptual framework in which vegetation diversity represents a bridge between abiotic factors and animal diversity. We show that vegetation diversity explains variation in animal richness not accounted for by altitudinal range or potential evapotranspiration, being the best predictor for butterflies, beetles, and amphibians. Moreover, the dissimilarity of plant community types explains the highest proportion of variation in animal assemblages across the studied regions, an effect that outperforms the effect of climate and their shared contribution with pure spatial variation. Our results at the country level suggest that vegetation diversity, as estimated from broad-scale classifications of plant communities, may contribute to our understanding of animal richness and may be disentangled, at least to a degree, from climate–energy and abiotic habitat heterogeneity.

  10. Explaining Andean megadiversity: the evolutionary and ecological causes of glassfrog elevational richness patterns.

    Science.gov (United States)

    Hutter, Carl R; Guayasamin, Juan M; Wiens, John J

    2013-09-01

    The Tropical Andes are an important global biodiversity hotspot, harbouring extraordinarily high richness and endemism. Although elevational richness and speciation have been studied independently in some Andean groups, the evolutionary and ecological processes that explain elevational richness patterns in the Andes have not been analysed together. Herein, we elucidate the processes underlying Andean richness patterns using glassfrogs (Centrolenidae) as a model system. Glassfrogs show the widespread mid-elevation diversity peak for both local and regional richness. Remarkably, these patterns are explained by greater time (montane museum) rather than faster speciation at mid-elevations (montane species pump), despite the recency of the major Andean uplift. We also show for the first time that rates of climatic-niche evolution and elevational change are related, supporting the hypothesis that climatic-niche conservatism decelerates species' shifts in elevational distributions and underlies the mid-elevation richness peak. These results may be relevant to other Andean clades and montane systems globally. © 2013 John Wiley & Sons Ltd/CNRS.

  11. Explaining the inefficiency of electrical distribution companies. Peruvian firms

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Reyes, Raul [Organismo Supervisor de la Inversion en Energia y Mineria, OSINERGMIN (Peru); Tovar, Beatriz [Infrastructure and Transport Research Group (EIT), Department of Applied Economics, University of Palmas de Gran Canaria (Spain)

    2010-09-15

    This paper investigates the extent to which the structural reform of the Peruvian electricity market, implemented in the 1990s, has improved the efficiency of the distribution companies; and it evaluates the influence on efficiency of firm specific explanatory variables. To do this, we rely on data from 14 distribution companies between 1996 and 2006. The results indicate that the incentives generated by the reform process led to the firms becoming more efficient. Moreover, the time trend and private management of the distribution companies are variables that positively affect the levels of efficiency, whereas the lower network densities are then the greater the inefficiency. (author)

  12. Regional Distribution Shifts Help Explain Local Changes in Wintering Raptor Abundance: Implications for Interpreting Population Trends

    Science.gov (United States)

    Paprocki, Neil; Heath, Julie A.; Novak, Stephen J.

    2014-01-01

    Studies of multiple taxa across broad-scales suggest that species distributions are shifting poleward in response to global climate change. Recognizing the influence of distribution shifts on population indices will be an important part of interpreting trends within management units because current practice often assumes that changes in local populations reflect local habitat conditions. However, the individual- and population-level processes that drive distribution shifts may occur across a large, regional scale and have little to do with the habitats within the management unit. We examined the latitudinal center of abundance for the winter distributions of six western North America raptor species using Christmas Bird Counts from 1975–2011. Also, we considered whether population indices within western North America Bird Conservation Regions (BCRs) were explained by distribution shifts. All six raptors had significant poleward shifts in their wintering distributions over time. Rough-legged Hawks (Buteo lagopus) and Golden Eagles (Aquila chrysaetos) showed the fastest rate of change, with 8.41 km yr−1 and 7.74 km yr−1 shifts, respectively. Raptors may be particularly responsive to warming winters because of variable migration tendencies, intraspecific competition for nesting sites that drives males to winter farther north, or both. Overall, 40% of BCR population trend models were improved by incorporating information about wintering distributions; however, support for the effect of distribution on BCR indices varied by species with Rough-legged Hawks showing the most evidence. These results emphasize the importance of understanding how regional distribution shifts influence local-scale population indices. If global climate change is altering distribution patterns, then trends within some management units may not reflect changes in local habitat conditions. The methods used to monitor and manage bird populations within local BCRs will fundamentally change as

  13. Vertical transmission explains the specific Burkholderia pattern in Sphagnum mosses at multi-geographic scale

    Science.gov (United States)

    Bragina, Anastasia; Cardinale, Massimiliano; Berg, Christian; Berg, Gabriele

    2013-01-01

    The betaproteobacterial genus Burkholderia is known for its versatile interactions with its hosts that can range from beneficial to pathogenic. A plant-beneficial-environmental (PBE) Burkholderia cluster was recently separated from the pathogen cluster, yet still little is known about burkholderial diversity, distribution, colonization, and transmission patterns on plants. In our study, we applied a combination of high-throughput molecular and microscopic methods to examine the aforementioned factors for Burkholderia communities associated with Sphagnum mosses – model plants for long-term associations – in Austrian and Russian bogs. Analysis of 16S rRNA gene amplicons libraries revealed that most of the Burkholderia are part of the PBE group, but a minor fraction was closely related to B. glathei and B. andropogonis from the pathogen cluster. Notably, Burkholderia showed highly similar composition patterns for each moss species independent of the geographic region, and Burkholderia-specific fluorescent in situ hybridization of Sphagnum gametophytes exhibited similar colonization patterns in different Sphagnum species at multi-geographic scales. To explain these patterns, we compared the compositions of the surrounding water, gametophyte-, and sporophyte-associated microbiome at genus level and discovered that Burkholderia were present in the Sphagnum sporophyte and gametophyte, but were absent in the flark water. Therefore, Burkholderia is a part of the core microbiome transmitted from the moss sporophyte to the gametophyte. This suggests a vertical transmission of Burkholderia strains, and thus underlines their importance for the plants themselves. PMID:24391630

  14. Distributed Cognition in Sports Teams: Explaining Successful and Expert Performance

    Science.gov (United States)

    Williamson, Kellie; Cox, Rochelle

    2014-01-01

    In this article we use a hybrid methodology to better understand the skilful performance of sports teams as an exemplar of distributed cognition. We highlight key differences between a team of individual experts (an aggregate system) and an expert team (an emergent system), and outline the kinds of shared characteristics likely to be found in an…

  15. Distribution of Cenozoic plant relicts in China explained by drought in dry season

    Science.gov (United States)

    Huang, Yongjiang; Jacques, Frédéric M. B.; Su, Tao; Ferguson, David K.; Tang, Hui; Chen, Wenyun; Zhou, Zhekun

    2015-01-01

    Cenozoic plant relicts are those groups that were once widespread in the Northern Hemisphere but are now restricted to some small isolated areas as a result of drastic climatic changes. They are good proxies to study how plants respond to climatic changes since their modern climatic requirements are known. Herein we look at the modern distribution of 65 palaeoendemic genera in China and compare it with the Chinese climatic pattern, in order to find a link between the plant distribution and climate. Central China and Taiwan Island are shown to be diversity centres of Cenozoic relict genera, consistent with the fact that these two regions have a shorter dry season with comparatively humid autumn and spring in China. Species distribution models indicate that the precipitation parameters are the most important variables to explain the distribution of relict genera. The Cenozoic wide-scale distribution of relict plants in the Northern Hemisphere is therefore considered to be linked to the widespread humid climate at that time, and the subsequent contraction of their distributional ranges was probably caused by the drying trend along with global cooling. PMID:26369980

  16. The neritic benthopelagic fauna: Which factors explain nocturnal distribution better?

    Science.gov (United States)

    Vereshchaka, Alexander L.; Anokhina, Ludmila L.

    2017-08-01

    Nocturnal sampling of mesoplankton above different biotopes at depths of 10, 20, and 40 m, with a temporal resolution of 10 min (98 hauls) was made and 76 taxa were identified. Six environmental factors were tested as the proximate cues for the distribution of individual taxa and integral community parameters: type of sea-floor biotope/depth (SFB), temperature (T), time after sunset (TAS), residual solar illumination, (assessed as time to midnight, TTM), moon phase (MP), and moon altitude (MA). Canonical Correspondence Analyses (CCAs), Bray-Curtis analyses (BCAs), and one-way ANOSIM and SIMPER tests were used to assess the impact of the environmental factors on the distribution of individual taxa, integral community parameters, and community structure. Seventy six taxa were recorded, with 17 taxa, mostly decapod larvae, contributing >1% of the total amount of sampled individuals. Four decapod species comprised over 50% of the total benthopelagic abundance. Decapod larvae migrated as benthopelagic fauna and aggregated over sites where adults live; this behaviour was observed both in zoea and in megalopa stages (ANOVA and SIMPER tests). SFB, T, and TTM are the best proximate cues for the nocturnal distribution of the neritic benthopelagic fauna. Significance of environmental factors may change with depth and sea-floor biotope type: T and TTM are equally important above all explored depths; impact of TAS decreased and contribution of MP and MA increased above greater depths. Further studies of the mesoplanktonic samples, which yield greatly richer material than macroplanktonic samples, may favour this analysis.

  17. Designing with objects object-oriented design patterns explained with stories from Harry Potter

    CERN Document Server

    Kak, Avinash C

    2014-01-01

     All code examples in the book are available for download on a companion site with resources for readers and instructors A refreshing alternative to the rather abstract and dry explanations of the  object-oriented design patterns in much of the existing literature on the subject In 24 chapters, Designing with Objects explains well-known design patterns by relating them to stories from the Harry Potter series

  18. Perilous proximity: Does the Janzen-Connell hypothesis explain the distribution of giant barrel sponges on a Florida coral reef?

    Science.gov (United States)

    Deignan, Lindsey K.; Pawlik, Joseph R.

    2015-06-01

    One popular concept used to explain the high biodiversity of some ecosystems is the Janzen-Connell hypothesis, which states that the distribution of conspecifics is controlled by species-specific pathogens or predators that are attracted to adults or to their reproductive output. The distribution of the affected species would then display a distinct pattern, with survivorship increasing at greater distance from the conspecific adult (negative density dependence), leaving a vacant area around the adult where other species can survive. The giant barrel sponge, Xestospongia muta, is an abundant and long-lived sponge on Caribbean coral reefs that is actively grazed by sponge-eating fishes and is susceptible to disease. We tested the Janzen-Connell hypothesis on barrel sponges on Conch Reef, Florida, by examining their distribution as a function of size using spatial point pattern analyses. Clark and Evans tests and a series of Ripley's K function analyses revealed no consistent distribution pattern, with most analyses resulting in a random pattern of sponge distribution. While predation by sponge-eating fishes has recently been discovered to structure sponge communities on reefs across the Caribbean, these top-down effects do not translate to spatial distributions of X. muta that support Janzen-Connell predictions.

  19. Facing the Heat: Does Desiccation and Thermal Stress Explain Patterns of Orientation in an Intertidal Invertebrate?

    Directory of Open Access Journals (Sweden)

    Clarissa M L Fraser

    Full Text Available A key challenge for ecologists is to quantify, explain and predict the ecology and behaviour of animals from knowledge of their basic physiology. Compared to our knowledge of many other types of distribution and behaviour, and how these are linked to individual function, we have a poor level of understanding of the causal basis for orientation behaviours. Most explanations for patterns of animal orientation assume that animals will modify their exposure to environmental factors by altering their orientation. We used a keystone grazer on rocky shores, the limpet Cellana tramoserica, to test this idea. Manipulative experiments were done to evaluate whether orientation during emersion affected limpet desiccation or body temperature. Body temperature was determined from infrared thermography, a technique that minimises disturbance to the test organism. No causal relationships were found between orientation and (i level of desiccation and (ii their body temperature. These results add to the growing knowledge that responses to desiccation and thermal stress may be less important in modifying the behaviour of intertidal organisms than previously supposed and that thermoregulation does not always reflect patterns of animal orientation. Much of what we understand about orientation comes from studies of animals able to modify orientation over very short time scales. Our data suggests that for animals whose location is less flexible, orientation decisions may have less to do with responses to environmental factors and more to do with structural habitat properties or intrinsic individual attributes. Therefore we suggest future studies into processes affecting orientation must include organisms with differing levels of behavioural plasticity.

  20. GWAS for male-pattern baldness identifies 71 susceptibility loci explaining 38% of the risk

    NARCIS (Netherlands)

    Pirastu, Nicola; Joshi, Peter K.; de Vries, Paul S.; Cornelis, Marilyn C.; McKeigue, Paul M.; Keum, NaNa; Franceschini, Nora; Colombo, Marco; Giovannucci, Edward L.; Spiliopoulou, Athina; Franke, Lude; North, Kari E.; Kraft, Peter; Morrison, Alanna C.; Esko, Tonu; Wilson, James F.

    2017-01-01

    Male pattern baldness (MPB) or androgenetic alopecia is one of the most common conditions affecting men, reaching a prevalence of similar to 50% by the age of 50; however, the known genes explain little of the heritability. Here, we present the results of a genome-wide association study including

  1. Presentation, distribution pattern, and management of diverticular ...

    African Journals Online (AJOL)

    We embark on this study aimed at evaluating the presentation, distribution pattern, and the management of diverticulosis in our tertiary health facility. Materials and Methods: A prospective descriptive study of the cases of diverticular disease seen between January 2007 and December 2011 at Obafemi Awolowo University ...

  2. Distribution pattern of surgically treated symptomatic prolapsed ...

    African Journals Online (AJOL)

    Background: The pattern of distribution of surgically treated symptomatic prolapsed lumbar and sacral intervertebral discs has been published, though scantily, especially in males. We decided to look at our own series, compare and contrast ours with some of those published. Materials and Methods: We treated 88 locations ...

  3. Landscape characteristics and coho salmon (Oncorhynchus kisutch) distributions: explaining abundance versus occupancy

    Science.gov (United States)

    E.A. Steel; D.W. Jensen; K.M. Burnett; K. Christiansen; J.C. Firman; B.E. Feist; K.J. Anlauf; D.P. Larsen

    2012-01-01

    Distribution of fishes, both occupancy and abundance, is often correlated with landscape-scale characteristics (e.g., geology, climate, and human disturbance). Understanding these relationships is essential for effective conservation of depressed populations. We used landscape characteristics to explain the distribution of coho salmon (Oncorhynchus kisutch...

  4. Distribution patterns of Iberian Carabidae (Insecta, Coleoptera

    Directory of Open Access Journals (Sweden)

    Serrano, José

    2003-12-01

    Full Text Available We have categorised the 1336 species and subspecies of the Iberian Peninsula according to the chorotype classification proposed by Vigna Taglianti et al. (1992, modified by the addition of new chorotypes. The Iberian Peninsula is noticeable among the different European and Circum-Mediterranean regions by the high proportion of endemic taxa (43.1%. The old age and stability of the northern half, the extreme position of the Peninsula within the Eurasiatic continent, alpine tectonics and abundance of caves are among the factors that have probably contributed to the origin of a distinctive fauna. Taxa with a large distribution pattern are predominant at a regional scale; the proportion of endemic taxa increases to the North and in mountain regions; Mediterranean elements are more frequent in the South whereas European elements increase in the northern half. Adaptation to a Mediterranean climatic regime and dispersal are two of the factors causing these patterns. The Peninsula is poor in Afrotropical elements, probably because of the strong isolation derived from the Sahara Desert. The Balearic Islands have high proportions of widely distributed and Mediterranean taxa, what suggests a main role of dispersal in the colonisation of the archipelago. The proportion of endemic taxa in Mallorca (7.8% is intermediate between that of Sardinia and Sicily; in spite of a relatively long isolation, the Balearic Islands are small in size and moderately rich in caves, what explains that most endemic taxa are found in the lowlands.

    Se han categorizado las 1336 especies y subespecies de la fauna ibérica de Carabidae, usando los corotipos propuestos por Vigna Taglianti et al. (1992, los cuales se han completado con algunos otros adicionales. La Península Ibérica destaca entre las diversas regiones europeas y circunmediterráneas por la elevada proporción de elementos endémicos (43,1%. La antigüedad y estabilidad de la mitad norte

  5. Periodically distributed objects with quasicrystalline diffraction pattern

    Energy Technology Data Exchange (ETDEWEB)

    Wolny, Janusz, E-mail: wolny@fis.agh.edu.pl; Strzalka, Radoslaw [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Kuczera, Pawel [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Laboratory of Crystallography, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich (Switzerland)

    2015-03-30

    It is possible to construct fully periodically distributed objects with a diffraction pattern identical to the one obtained for quasicrystals. These objects are probability distributions of distances obtained in the statistical approach to aperiodic structures distributed periodically. The diffraction patterns have been derived by using a two-mode Fourier transform—a very powerful method not used in classical crystallography. It is shown that if scaling is present in the structure, this two-mode Fourier transform can be reduced to a regular Fourier transform with appropriately rescaled scattering vectors and added phases. Detailed case studies for model sets 1D Fibonacci chain and 2D Penrose tiling are discussed. Finally, it is shown that crystalline, quasicrystalline, and approximant structures can be treated in the same way.

  6. Fat distribution patterns in young amenorrheic females.

    Science.gov (United States)

    Kirchengast, S; Huber, J

    2001-06-01

    The present study analyzes body fat distribution, a well-known and important indicator of reproductive capability, in young women between 18 and 28 years of age (mean=23.3 years) suffering from secondary amenorrhea and therefore temporary infertility resulting from self-starvation. Body composition parameters estimated by means of dual energy x-ray absorptiometry and the fat distribution index, indicating body shape, were compared with those of healthy controls. Although members of the infertile, amenorrheic group exhibited dramatically low body weight and total amount of body fat, and therefore a marked negative energy balance in comparison with the healthy controls, the sex-specific fat distribution patterns did not differ between infertile and fertile young women. In contrast, the lower the weight and total fat amount, the more gynoid the fat distribution, even in infertile women. This observation may be interpreted in an evolutionary sense: Our ancestors had to cope with frequent food shortages, even starvation, and therefore lengthy periods of negative energy balance. In addition to pregnancy and lactation, temporary infertility as a result of long-term negative energy balance was not an uncommon phenomenon in female life histories. Nevertheless, after a time of plenty, reproductive function recovered, and therefore the gynoid fat distribution patterns in temporarily infertile young women may be interpreted as signal of reproductive capability, which resumes after a time of surplus.

  7. Microhabitat and Climatic Niche Change Explain Patterns of Diversification among Frog Families.

    Science.gov (United States)

    Moen, Daniel S; Wiens, John J

    2017-07-01

    A major goal of ecology and evolutionary biology is to explain patterns of species richness among clades. Differences in rates of net diversification (speciation minus extinction over time) may often explain these patterns, but the factors that drive variation in diversification rates remain uncertain. Three important candidates are climatic niche position (e.g., whether clades are primarily temperate or tropical), rates of climatic niche change among species within clades, and microhabitat (e.g., aquatic, terrestrial, arboreal). The first two factors have been tested separately in several studies, but the relative importance of all three is largely unknown. Here we explore the correlates of diversification among families of frogs, which collectively represent ∼88% of amphibian species. We assemble and analyze data on phylogeny, climate, and microhabitat for thousands of species. We find that the best-fitting phylogenetic multiple regression model includes all three types of variables: microhabitat, rates of climatic niche change, and climatic niche position. This model explains 67% of the variation in diversification rates among frog families, with arboreal microhabitat explaining ∼31%, niche rates ∼25%, and climatic niche position ∼11%. Surprisingly, we show that microhabitat can have a much stronger influence on diversification than climatic niche position or rates of climatic niche change.

  8. The coexistence of acorns with different maturation patterns explains acorn production variability in cork oak.

    Science.gov (United States)

    Pons, Josep; Pausas, Juli G

    2012-07-01

    In dry areas such as Mediterranean ecosystems, fluctuations in seed production are typically explained by resource (water) availability. However, acorn production in cork oak (Quercus suber) populations shows a very low relationship to weather. Because cork oak trees produce acorns with different maturation patterns (annual and biennial), we hypothesized that acorn production in coexisting individuals with a different dominant acorn maturation type should respond differently to climatic factors and that disaggregating the trees according to their acorn-maturation pattern should provide a more proximal relation to weather factors. We assessed acorn production variability in fragmented cork oak populations of the eastern Iberian Peninsula by counting the total number of acorns in 155 trees during an 8-year period. An initial assessment of acorn production variability in relation to weather parameters yielded very low explained variance (7%). However, after the trees were grouped according to their dominant acorn maturation pattern, weather parameters were found to account for 44% of the variability in acorn crops, with trees with annual acorns exhibiting mast fruiting in years with reduced spring frost and shorter summer droughts and trees with biennial acorns showing the opposite pattern. Thus, conditions that negatively affect annual production could be beneficial for biennial production (and vice versa). The results highlight the importance of the resource-matching hypothesis for explaining acorn production in Quercus suber and suggest that different seed maturation types within a population may allow the species to deal with highly variable weather conditions. They also emphasize the importance of understanding acorn maturation patterns for interpreting masting cycles.

  9. Causal trait theories: a new form of person knowledge that explains egocentric pattern projection.

    Science.gov (United States)

    Critcher, Clayton R; Dunning, David; Rom, Sarah C

    2015-03-01

    Representations of the self and others include not only piecemeal traits but also causal trait theories-explanations for why a person's standing on 1 trait causes or is caused by standings on other traits (Studies 1a-1c). These causal theories help resolve the puzzle of egocentric pattern projection-the tendency for people to assume that traits correlate in the population in the same way they align in the self. Causal trait theories-created to explain trait co-occurrence in a single person-are exported to guide one's implicit personality theories about people in general (Study 2). Pattern projection was found to be largely egocentric (i.e., more strong guided by self- than by social perceptions) for 2 reasons. First, causal trait theories are more numerous for the self. When participants were prompted to generate causal trait theories about someone else, they pattern projected more from that person (Study 3). Second, causal trait theories about the self are more likely to draw on behavioral information from multiple contexts instead of merely seeking to explain why 2 traits co-occur in a single context. Causal trait theories based on trait-relevant behaviors from different contexts, instead of trait co-occurrence within a single context, produce more pattern projection (Study 4). Implications for self and social cognition are discussed. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  10. Simulating the Cinema Market : How cross-cultural differences in social influence explain box office distributions

    NARCIS (Netherlands)

    Broekhuizen, T.L.J.; Delre, S.A.; Torres, A.

    This paper uses a mixed method approach to show how cross-cultural differences in social influences can explain differences in distributions of market shares in different markets. First, we develop a realistic agent-based model that mimics the behavior of movie visitors and incorporates the social

  11. Ahead of the pack? : Explaining the unequal distribution of scholarships in Germany

    NARCIS (Netherlands)

    Haas, C.; van de Werfhorst, H.

    2016-01-01

    This article investigates to what extent scholarships are unequally distributed among students in Germany and how these inequalities can be explained. Following sociological theory, the article argues that elites seek qualitative ways of distinguishing themselves in a mass higher education system.

  12. Ahead of the Pack? Explaining the Unequal Distribution of Scholarships in Germany

    Science.gov (United States)

    Haas, Christina; Van De Werfhorst, Herman

    2017-01-01

    This article investigates to what extent scholarships are unequally distributed among students in Germany and how these inequalities can be explained. Following sociological theory, the article argues that elites seek qualitative ways of distinguishing themselves in a mass higher education system. Using student surveys, we demonstrate that class…

  13. Macroecological factors explain large-scale spatial population patterns of ancient agriculturalists

    NARCIS (Netherlands)

    Xu, C.; Chen, B.; Abades, S.; Reino, L.; Teng, S.; Ljungqvist, F.C.; Huang, Z.Y.X.; Liu, X.

    2015-01-01

    Aim: It has been well demonstrated that the large-scale distribution patterns of numerous species are driven by similar macroecological factors. However, understanding of this topic remains limited when applied to our own species. Here we take a large-scale look at ancient agriculturalist

  14. Global patterns of city size distributions and their fundamental drivers.

    Directory of Open Access Journals (Sweden)

    Ethan H Decker

    Full Text Available Urban areas and their voracious appetites are increasingly dominating the flows of energy and materials around the globe. Understanding the size distribution and dynamics of urban areas is vital if we are to manage their growth and mitigate their negative impacts on global ecosystems. For over 50 years, city size distributions have been assumed to universally follow a power function, and many theories have been put forth to explain what has become known as Zipf's law (the instance where the exponent of the power function equals unity. Most previous studies, however, only include the largest cities that comprise the tail of the distribution. Here we show that national, regional and continental city size distributions, whether based on census data or inferred from cluster areas of remotely-sensed nighttime lights, are in fact lognormally distributed through the majority of cities and only approach power functions for the largest cities in the distribution tails. To explore generating processes, we use a simple model incorporating only two basic human dynamics, migration and reproduction, that nonetheless generates distributions very similar to those found empirically. Our results suggest that macroscopic patterns of human settlements may be far more constrained by fundamental ecological principles than more fine-scale socioeconomic factors.

  15. Breast compression in mammography: pressure distribution patterns

    Energy Technology Data Exchange (ETDEWEB)

    Dustler, Magnus; Froejd, Patrik; Mattsson, Soeren; Tingberg, Anders; Foernvik, Daniel [Medical Radiation Physics, Lund Univ., Skaane Univ. Hospital, Malmoe (Sweden)], E-mail: Magnus.Dustler@med.lu.se; Andersson, Ingvar; Zackrisson, Sophia [Diagnostic Centre of Imaging and Functional Medicine, Lund Univ., Skaane Univ. Hospital, Malmoe (Sweden); Brorson, Haakan [Plastic and Reconstructive Surgery, Dept. of Clinical Sciences Malmoe, Lund Univ., Skaane Univ. Hospital, Malmoe (Sweden)

    2012-11-15

    Background Breast compression is important in mammography in order to improve image quality, better separate tissue components, and reduce absorbed dose to the breast. In this study we use a method to measure and visualize the distribution of pressure over a compressed breast in mammography. Purpose To measure and describe the pressure distribution over the breast as a result of applied breast compression in mammography. Material and Methods One hundred and three women aged 40.7-74.3 years (median, 48.9 years) invited for mammographic screening consented to take part in this study. They were subjected to two additional breast compressions of the left breast (standard force and approximately 50% reduction). Pressure images of the compressed breast were obtained using force sensing resistor (FSR) sensors placed underneath the compression plate. Subjects rated their experience of pain on a visual analogue scale (VAS). Results Four pressure patterns were identified, fitting 81 of the 103 breasts, which were grouped accordingly. The remaining 22 breasts were found to correspond to a combination of any two patterns. Two groups (43 breasts) showed pressure mainly over the juxtathoracic part of the breast, had significantly greater breast thickness (P = 0.003) and had a lower mean pressure over dense tissue (P < 0.0001) than those with more evenly distributed pressure. Reducing compression force increased average breast thickness by 1.8 mm (P < 0.0001). Conclusion The distribution of pressure differed greatly between breasts. In a large proportion of breasts the compression plate did not provide optimal compression of the breast, the compression force being absorbed in juxtathoracic structures.

  16. Color Distribution Pattern Metric for Person Reidentification

    Directory of Open Access Journals (Sweden)

    Yingsheng Ye

    2017-01-01

    Full Text Available Accompanying the growth of surveillance infrastructures, surveillance IP cameras mount up rapidly, crowding Internet of Things (IoT with countless surveillance frames and increasing the need of person reidentification (Re-ID in video searching for surveillance and forensic fields. In real scenarios, performance of current proposed Re-ID methods suffers from pose and viewpoint variations due to feature extraction containing background pixels and fixed feature selection strategy for pose and viewpoint variations. To deal with pose and viewpoint variations, we propose the color distribution pattern metric (CDPM method, employing color distribution pattern (CDP for feature representation and SVM for classification. Different from other methods, CDP does not extract features over a certain number of dense blocks and is free from varied pedestrian image resolutions and resizing distortion. Moreover, it provides more precise features with less background influences under different body types, severe pose variations, and viewpoint variations. Experimental results show that our CDPM method achieves state-of-the-art performance on both 3DPeS dataset and ImageLab Pedestrian Recognition dataset with 68.8% and 79.8% rank 1 accuracy, respectively, under the single-shot experimental setting.

  17. Do competitive interactions in dry heathlands explain plant abundance patterns and species coexistence?

    DEFF Research Database (Denmark)

    Ransijn, Johannes; Damgaard, Christian; Schmidt, Inger K

    2015-01-01

    Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... and uses this to assess the outcome of competitive interactions and to predict community patterns and dynamics in a Northwest-European dry heathland. Inferred competitive interactions from five consecutive years of measurements in permanent vegetation frames at a single dry heathland site were used...... to predict the community dynamics of C. vulgaris and D. flexuosa. This was compared with the observed plant community structure at 198 Danish dry heathland sites. Interspecific competition will most likely lead to competitive exclusion of D. flexuosa at the observed temporal and spatial scale...

  18. How can one explain changes in the monthly pattern of suicide?

    CERN Document Server

    Roehner, Bertrand M

    2014-01-01

    The monthly pattern of suicides has remained a puzzle ever since it was discovered in the second half of the 19th century. In this paper we intend to "explain" not the pattern itself but rather its changes across countries and in the course of time. First, we show that the fairly common idea according to which this pattern is decaying in "modern" societies is not altogether true. For instance, around 2000, in well urbanized countries like South Korea or Spain this pattern was still as strong as it was in France (and other European countries) in the late 19th century. The method that we use in order to make some progress in our understanding is the time-honoured Cartesian approach of breaking up the problem under consideration "into as many parts as might be necessary to solve it". More specifically, we try two decompositions of monthly suicides: (i) according to suicide methods (ii) according to age-groups. The first decomposition points out the key-role of hanging and drowning. The second shows the crucial r...

  19. Multiple factors and thresholds explaining fish species distributions in lowland streams

    Directory of Open Access Journals (Sweden)

    Cristina Trigal

    2015-07-01

    Full Text Available Appropriate restoration and conservation measures require a good understanding of the factors limiting the distribution of species, the presence of steep changes in the distribution along environmental gradients and the effect of environmental interactions on species distribution. We used 12 environmental variables describing connectivity, hydrology, climate and stream morphology, to model the distributions of 17 fish species from 2005 Swedish stream sites that were sampled between 2000 and 2011. Modeling was performed using boosted regression trees and random forest, two machine learning techniques to assess the relationship between species distributions and their environment. Temperature, width and connectivity (minimum distance to lake or the sea and water discharge, were the most important variables explaining changes in species distribution at large spatial scales. Response curves of fitted occurrence probabilities along predictors often showed abrupt changes, however, clear threshold effects were difficult to detect. Our results show also differences across species and even in the outcomes of the two algorithms, implying that a simultaneous assessment of multiple species may provide a better signal of ecosystem change than the use of surrogate species.

  20. Kin-Aggregations Explain Chaotic Genetic Patchiness, a Commonly Observed Genetic Pattern, in a Marine Fish.

    Directory of Open Access Journals (Sweden)

    Jason D Selwyn

    Full Text Available The phenomenon of chaotic genetic patchiness is a pattern commonly seen in marine organisms, particularly those with demersal adults and pelagic larvae. This pattern is usually associated with sweepstakes recruitment and variable reproductive success. Here we investigate the biological underpinnings of this pattern in a species of marine goby Coryphopterus personatus. We find that populations of this species show tell-tale signs of chaotic genetic patchiness including: small, but significant, differences in genetic structure over short distances; a non-equilibrium or "chaotic" pattern of differentiation among locations in space; and within locus, within population deviations from the expectations of Hardy-Weinberg equilibrium (HWE. We show that despite having a pelagic larval stage, and a wide distribution across Caribbean coral reefs, this species forms groups of highly related individuals at small spatial scales (<10 metres. These spatially clustered family groups cause the observed deviations from HWE and local population differentiation, a finding that is rarely demonstrated, but could be more common than previously thought.

  1. Habitat availability does not explain the species richness patterns of European lentic and lotic freshwater animals

    DEFF Research Database (Denmark)

    Dehling, D.M.; Hof, C.; Brandle, M.

    2010-01-01

    Aim In Europe, the relationships between species richness and latitude differ for lentic (standing water) and lotic (running water) species. Freshwater animals are highly dependent on suitable habitat, and thus the distribution of available habitat should strongly influence large-scale patterns...... of species richness. We tested whether habitat availability can account for the differences in species richness patterns between European lentic and lotic freshwater animals. Location Europe. Methods We compiled occurrence data of 1959 lentic and 2445 lotic species as well as data on the amount of lentic...... and lotic habitats across 25 pre-defined biogeographical regions of European freshwaters. We used the range of elevation of each region as a proxy for habitat diversity. We investigated the relationships between species richness, habitat availability and habitat diversity with univariate and multiple...

  2. Evolutionary fields can explain patterns of high-dimensional complexity in ecology.

    Science.gov (United States)

    Wilsenach, James; Landi, Pietro; Hui, Cang

    2017-04-01

    One of the properties that make ecological systems so unique is the range of complex behavioral patterns that can be exhibited by even the simplest communities with only a few species. Much of this complexity is commonly attributed to stochastic factors that have very high-degrees of freedom. Orthodox study of the evolution of these simple networks has generally been limited in its ability to explain complexity, since it restricts evolutionary adaptation to an inertia-free process with few degrees of freedom in which only gradual, moderately complex behaviors are possible. We propose a model inspired by particle-mediated field phenomena in classical physics in combination with fundamental concepts in adaptation, which suggests that small but high-dimensional chaotic dynamics near to the adaptive trait optimum could help explain complex properties shared by most ecological datasets, such as aperiodicity and pink, fractal noise spectra. By examining a simple predator-prey model and appealing to real ecological data, we show that this type of complexity could be easily confused for or confounded by stochasticity, especially when spurred on or amplified by stochastic factors that share variational and spectral properties with the underlying dynamics.

  3. Evolutionary fields can explain patterns of high-dimensional complexity in ecology

    Science.gov (United States)

    Wilsenach, James; Landi, Pietro; Hui, Cang

    2017-04-01

    One of the properties that make ecological systems so unique is the range of complex behavioral patterns that can be exhibited by even the simplest communities with only a few species. Much of this complexity is commonly attributed to stochastic factors that have very high-degrees of freedom. Orthodox study of the evolution of these simple networks has generally been limited in its ability to explain complexity, since it restricts evolutionary adaptation to an inertia-free process with few degrees of freedom in which only gradual, moderately complex behaviors are possible. We propose a model inspired by particle-mediated field phenomena in classical physics in combination with fundamental concepts in adaptation, which suggests that small but high-dimensional chaotic dynamics near to the adaptive trait optimum could help explain complex properties shared by most ecological datasets, such as aperiodicity and pink, fractal noise spectra. By examining a simple predator-prey model and appealing to real ecological data, we show that this type of complexity could be easily confused for or confounded by stochasticity, especially when spurred on or amplified by stochastic factors that share variational and spectral properties with the underlying dynamics.

  4. A large historical refugium explains spatial patterns of genetic diversity in a Neotropical savanna tree species.

    Science.gov (United States)

    Souza, Helena Augusta Viana E; Collevatti, Rosane Garcia; Lima-Ribeiro, Matheus S; Lemos-Filho, José Pires de; Lovato, Maria Bernadete

    2017-01-01

    The relative role of Pleistocene climate changes in driving the geographic distribution and genetic diversity of South American species is not well known, especially from open biomes such as the Cerrado, the most diverse tropical savanna, encompassing high levels of endemism. Here the effects of Quaternary climatic changes on demographic history, distribution dynamics and genetic diversity of Dimorphandra mollis, an endemic tree species widely distributed in the Cerrado, were investigated. A total of 38 populations covering most of the distribution of D. mollis were analysed using internal transcribed spacer (ITS) sequences and nuclear microsatellite variation [simple sequence repeats (SSRs)]. The framework incorporated statistical phylogeography, coalescent analyses and ecological niche modelling (ENM). Different signatures of Quaternary climatic changes were found for ITS sequences and SSRs corresponding to different time slices. Coalescent analyses revealed large and constant effective population sizes, with high historical connectivity among the populations for ITS sequences and low effective population sizes and gene flow with recent population retraction for SSRs. ENMs indicated a slight geographical range retraction during the Last Glacial Maximum. A large historical refugium across central Brazil was predicted. Spatially explicit analyses showed a spatial cline pattern in genetic diversity related to the paleodistribution of D. mollis and to the centre of its historical refugium. The complex genetic patterns found in D. mollis are the result of a slight geographical range retraction during the Last Glacial Maximum followed by population expansion to the east and south from a large refugium in the central part of the Cerrado. This historical refugium is coincident with an area predicted to be climatically stable under future climate scenarios. The identified refugium should be given high priority in conservation polices to safeguard the evolutionary

  5. Strong but diverging clonality - climate relationships of different plant clades explain weak overall pattern across China

    Science.gov (United States)

    Ye, Duo; Liu, Guofang; Song, Yao-Bin; Cornwell, William K.; Dong, Ming; Cornelissen, Johannes H. C.

    2016-06-01

    The clonal strategy should be relatively important in stressful environments (i.e. of low resource availability or harsh climate), e.g. in cold habitats. However, our understanding of the distribution pattern of clonality along environmental gradients is still far from universal. The weakness and inconsistency of overall clonality-climate relationships across taxa, as reported in previous studies, may be due to different phylogenetic lineages having fundamental differences in functional traits other than clonality determining their climate response. Thus, in this study we compared the clonality-climate relationships along a latitudinal gradient within and between different lineages at several taxonomic levels, including four major angiosperm lineages (Magnoliidae, Monocotyledoneae, Superrosidae and Superasteridae), orders and families. To this aim we used a species clonality dataset for 4015 vascular plant species in 545 terrestrial communities across China. Our results revealed clear predictive patterns of clonality proportion in relation to environmental gradients for the predominant representatives of each of the taxonomic levels above, but the relationships differed in shape and strength between the 4 major angiosperm lineages, between the 12 orders and between the 12 families. These different relationships canceled out one another when all lineages at a certain taxonomic level were pooled. Our findings highlight the importance of explicitly accounting for the functional or taxonomic scale for studying variation in plant ecological strategy across environmental gradients.

  6. Effects of habitat fragmentation and road density on the distribution pattern of the moor frog Rana arvalis.

    NARCIS (Netherlands)

    Vos, C.C.; Chardon, P.

    1998-01-01

    1. The effects of habitat fragmentation on the distribution pattern of the moor frog Rana arvalis were investigated. Also, the possible isolation effects of the road network were taken into account. 2. Indications were found that habitat fragmentation partly explains the distribution pattern of the

  7. Does competition for phosphate supply explain the invasion pattern of Elodea species?

    Science.gov (United States)

    Thiébaut, Gabrielle

    2005-09-01

    Two invasive aquatic plants, Elodea canadensis and Elodea nuttallii, occurred in north-eastern France. In this study, we examine the influence of phosphorus availability in soft water streams to explain the invasion pattern of exotic species (E. nuttallii and E. canadensis) compared to native plants (Callitriche platycarpa, Ranunculus peltatus). Total phosphorus was measured in these four aquatic macrophytes. Sediment total phosphorus and water-soluble reactive phosphorus were also analysed each season in 2001. Phosphorus content in the two invasive species and in R. peltatus was higher than in C. platycarpa. Elodea species are adapted to the seasonal phosphorus fluctuations as well as R. peltatus and exhibited high phosphorus storage ability. The high fluctuation availability of resources in space or/and time favoured the spread of the invasive plants and confirms the theory of invasibility of Davis et al. [2000. Fluctuating resources in plant communities: a general theory of invasibility. J. Ecol. 88, 528-534]. The eutrophication process increases the invasibility of E. nuttallii's, while inducing competition between E. nuttallii and native macrophyte species.

  8. Explaining bathymetric diversity patterns in marine benthic invertebrates and demersal fishes: physiological contributions to adaptation of life at depth.

    Science.gov (United States)

    Brown, Alastair; Thatje, Sven

    2014-05-01

    Bathymetric biodiversity patterns of marine benthic invertebrates and demersal fishes have been identified in the extant fauna of the deep continental margins. Depth zonation is widespread and evident through a transition between shelf and slope fauna from the shelf break to 1000 m, and a transition between slope and abyssal fauna from 2000 to 3000 m; these transitions are characterised by high species turnover. A unimodal pattern of diversity with depth peaks between 1000 and 3000 m, despite the relatively low area represented by these depths. Zonation is thought to result from the colonisation of the deep sea by shallow-water organisms following multiple mass extinction events throughout the Phanerozoic. The effects of low temperature and high pressure act across hierarchical levels of biological organisation and appear sufficient to limit the distributions of such shallow-water species. Hydrostatic pressures of bathyal depths have consistently been identified experimentally as the maximum tolerated by shallow-water and upper bathyal benthic invertebrates at in situ temperatures, and adaptation appears required for passage to deeper water in both benthic invertebrates and demersal fishes. Together, this suggests that a hyperbaric and thermal physiological bottleneck at bathyal depths contributes to bathymetric zonation. The peak of the unimodal diversity-depth pattern typically occurs at these depths even though the area represented by these depths is relatively low. Although it is recognised that, over long evolutionary time scales, shallow-water diversity patterns are driven by speciation, little consideration has been given to the potential implications for species distribution patterns with depth. Molecular and morphological evidence indicates that cool bathyal waters are the primary site of adaptive radiation in the deep sea, and we hypothesise that bathymetric variation in speciation rates could drive the unimodal diversity-depth pattern over time. Thermal

  9. Biological traits explain the distribution and colonisation ability of the invasive shore crab Hemigrapsus takanoi

    Science.gov (United States)

    Gothland, M.; Dauvin, J. C.; Denis, L.; Dufossé, F.; Jobert, S.; Ovaert, J.; Pezy, J. P.; Tous Rius, A.; Spilmont, N.

    2014-04-01

    Comprehending marine invasions requires a better knowledge of the biological traits of invasive species, and the future spread of invasive species may be predicted through comprehensive overviews of their distribution. This study thus presents the current distribution of a non-indigenous species, the Asian shore crab Hemigrapsus takanoi, as well as the species population characteristics (size distribution and cohorts), based on a five-year survey (2008-2012) along the French coast of the English Channel. Two large populations were found near harbours: one on the Opal Coast (where density reached 61 ± 22 ind.m-2, mean ± s.d., in Dunkirk harbour) and one on the Calvados coast (density up to 26 ± 6 ind.m-2, mean ± s.d, in Honfleur harbour). H. takanoi exhibited a short life cycle, a rapid growth, an early sexual maturity and a high adult mortality. These features, combined with previously described high fecundity and high dispersal ability, endow this species with an 'r-selected strategy'. This strategy, which usually characterises species with a high colonisation ability, would explain the success of H. takanoi for colonising the French coast of the Channel. However, the species was found only in harbours and their vicinity; H. takanoi thus exhibited a discontinuous distribution along the 700 km of coastline. These results are discussed regarding sediment preference and potential introduction vectors. Hemigrapsus takanoi is now considered as established on the French coast and further studies are needed to evaluate the consequences of its introduction on the structure and functioning of the impacted shores.

  10. Distribution Pattern of Healthcare Facilities in Osun State, Nigeria ...

    African Journals Online (AJOL)

    Distribution Pattern of Healthcare Facilities in Osun State, Nigeria. ... Ethiopian Journal of Environmental Studies and Management ... Accessibility to healthcare facilities has generally been identified as a major indicator of development, and the existing spatial pattern of distribution of healthcare facilities play very prominent ...

  11. Distribution and antibiotic susceptibility pattern of methicillin ...

    African Journals Online (AJOL)

    Background: The rise of methicillin resistant Staphylococcus aureus (MRSA) infection has become a serious health issue. The emergence of mutidrug – resistant MRSA strains compounds chemotherapy and has raised public health concern. In this preliminary study, the distribution and antimicrobial susceptibility profile of ...

  12. Vegetation community structure, composition and distribution pattern ...

    African Journals Online (AJOL)

    There was no significant difference in species diversity between sampling areas, which had a Shannon's diversity index ranging from 1.64 to 2.63. ... We conclude that habitat characteristics, fire, past and the present exploitation clearly influence the species diversity, distribution and variation in vegetation communities.

  13. Long-term climate and competition explain regional forest mortality patterns under extreme drought

    Science.gov (United States)

    Young, D. J.; Latimer, A.; Stevens, J. T.; Earles, J. M.; Ellis, A.; Jirka, A.; Moore, J.

    2016-12-01

    Rising temperatures are amplifying drought-induced stress and mortality in forests globally. It remains uncertain, however, how tree mortality in drought-affected regions will be distributed across environments. In particular, during a regional drought, will areas that are already generally dry experience the most mortality? For any given level of aridity, will more mortality be associated with more intense competition? To answer these questions, we investigated the effects of average aridity (i.e., 35-year mean annual climatic water deficit) and competition (i.e., tree basal area) on tree mortality patterns using regional-scale aerial mortality surveys conducted by the U.S. Forest Service throughout the forests of California during a four-year statewide extreme drought from 2012 to 2015. We used statistical models to relate these mortality data to regional-scale climate layers we developed to represent long-term and annual climatic conditions and coarse-scale plant water balance, and to independent gridded estimates of tree basal area. We found that tree mortality increased by an order of magnitude during this period, spiking dramatically during 2015, the fourth year of drought. Tree mortality rates were associated with both long-term average climatic water deficit and tree basal area, as well as with the interaction of these factors, so that the highest mortality tended to occur in forests with high CWD and basal area. By identifying areas that are high in tree basal area relative to their level of CWD, these results can assist forest managers and policy-makers in identifying the most drought-vulnerable forests across broad geographic areas.

  14. Low predictive power of mid-domain effect to explain geographic species richness patterns in Palearctic songbirds

    NARCIS (Netherlands)

    Aliabadian, M.; Roselaar, C.S.; Sluys, R.; Nijman, V.

    2007-01-01

    In the study of diversity patterns, the Mid-domain effect (MDE), which explains gradients in diversity solely on the basis of geometric constraints, has emerged as a null-model against which other hypotheses can be tested. The effectiveness, measured by its predictive power, of these MDE models

  15. Development of Spatial Distribution Patterns by Biofilm Cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Hansen, Susse Kirkelund; Bak Christensen, Bjarke

    2015-01-01

    Confined spatial patterns of microbial distribution are prevalent in nature, such as in microbial mats, soil communities, and water stream biofilms. The symbiotic two-species consortium of Pseudomonas putida and Acinetobacter sp. C6, originally isolated from a creosote-polluted aquifer, has evolved...... in the context of species distribution patterns observed in macroecology, and we summarize observations about the processes involved in co-adaptation between P. putida and Acinetobacter sp. C6. Our results contribute to an understanding of spatial species distribution patterns as they are observed in nature...

  16. Estimating the Distribution of Dietary Consumption Patterns

    KAUST Repository

    Carroll, Raymond J.

    2014-02-01

    In the United States the preferred method of obtaining dietary intake data is the 24-hour dietary recall, yet the measure of most interest is usual or long-term average daily intake, which is impossible to measure. Thus, usual dietary intake is assessed with considerable measurement error. We were interested in estimating the population distribution of the Healthy Eating Index-2005 (HEI-2005), a multi-component dietary quality index involving ratios of interrelated dietary components to energy, among children aged 2-8 in the United States, using a national survey and incorporating survey weights. We developed a highly nonlinear, multivariate zero-inflated data model with measurement error to address this question. Standard nonlinear mixed model software such as SAS NLMIXED cannot handle this problem. We found that taking a Bayesian approach, and using MCMC, resolved the computational issues and doing so enabled us to provide a realistic distribution estimate for the HEI-2005 total score. While our computation and thinking in solving this problem was Bayesian, we relied on the well-known close relationship between Bayesian posterior means and maximum likelihood, the latter not computationally feasible, and thus were able to develop standard errors using balanced repeated replication, a survey-sampling approach.

  17. Patterns of bird and mammal distribution in Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The present distributional patterns of birds and mammals on the surface of the earth are the combined result of historic and current factors. The historic factors...

  18. The impact of fracking on freight distribution patterns.

    Science.gov (United States)

    2016-11-01

    The increasing production of domestic energy through the use of fracking will likely alter local/regional/national economies and corresponding freight distribution patterns (highway, rail, marine, pipeline) in the United States. The proposed project ...

  19. Intermodal transport and distribution patterns in ports relationship to hinterland

    Science.gov (United States)

    Dinu, O.; Dragu, V.; Ruscă, F.; Ilie, A.; Oprea, C.

    2017-08-01

    It is of great importance to examine all interactions between ports, terminals, intermodal transport and logistic actors of distribution channels, as their optimization can lead to operational improvement. Proposed paper starts with a brief overview of different goods types and allocation of their logistic costs, with emphasis on storage component. Present trend is to optimize storage costs by means of port storage area buffer function, by making the best use of free storage time available, most of the ports offer. As a research methodology, starting point is to consider the cost structure of a generic intermodal transport (storage, handling and transport costs) and to link this to intermodal distribution patterns most frequently cast-off in port relationship to hinterland. The next step is to evaluate storage costs impact on distribution pattern selection. For a given value of port free storage time, a corresponding value of total storage time in the distribution channel can be identified, in order to substantiate a distribution pattern shift. Different scenarios for transport and handling costs variation, recorded when distribution pattern shift, are integrated in order to establish the reaction of the actors involved in port related logistic and intermodal transport costs evolution is analysed in order to optimize distribution pattern selection.

  20. Patterns in exoplanet count and eccentricity distributions

    Science.gov (United States)

    Taylor, Stuart F.

    2018-01-01

    The distribution of exoplanets of contains an unexpected level of features, starting with an unexpected gap the splits the main pileup of much of the planet population. In the population of planets of metal-rich sunlike single stars (SLSS objects), which comprises 40% of planets found by the radial velocity method, when counting logarithmic periods the main pileup of planets with periods longer than 100 days is split into two peaks separated by a significant gap. There is a wide region which has so few planets that none are found in the current data set. We show that this gap is extremely unlikely to occur by random. Because this gap is well-filled among planets of low surface gravity and low metallicity stars with 31 objects, it is unlikely that the bimodal nature of the metal rich SLSS population is due to observational effects. Comparisons of eccentricity of the metal-rich and metal-poor SLSS populations depend strongly on the two-peak-gap structure of counts of the metal-rich SLSS (rSLSS) population. Consideration of these features is essential to properly study the correlations of eccentricity with other planet-system parameters given how the eccentricity of rSLSS objects is highest in the two peaks of the rSLSS population.

  1. Distribution pattern of histone H3 phosphorylation at serine 10 ...

    Indian Academy of Sciences (India)

    2013-08-06

    Aug 6, 2013 ... in chromosome distribution of H3S10ph when mitosis and meiosis were compared. ... [Paula C. M. P., Techio V. H., Sobrinho F. S. and Freitas A. S. 2013 Distribution pattern of histone H3 phosphorylation at serine 10 during mitosis and meiosis in ... RDWebster], since current knowledge about specific roles ...

  2. Distribution Pattern of Healthcare Facilities in Osun State, Nigeria ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    existing spatial pattern of distribution of healthcare facilities play very prominent role in gauging the level of efficiency or otherwise of the existing level of ... 1998). In investigating the level of provision of central facilities (like healthcare), emphasis .... It is important to note that other statistical measure of spatial distribution of ...

  3. Zoogeographical Patterns in the Distribution of East African ...

    African Journals Online (AJOL)

    The savanna fauna of treefrogs in East Africa includes five distributional patterns: a widely distributed element, an element in the savanna north of the central forest from Cameroun to northern East Africa. an element south of the central forest, an East African lowland fauna. and an element in the dry savanna of Kenya and ...

  4. Changes in pattern completion--a key mechanism to explain age-related recognition memory deficits?

    Science.gov (United States)

    Vieweg, Paula; Stangl, Matthias; Howard, Lorelei R; Wolbers, Thomas

    2015-03-01

    Accurate memory retrieval from partial or degraded input requires the reactivation of memory traces, a hippocampal mechanism termed pattern completion. Age-related changes in hippocampal integrity have been hypothesized to shift the balance of memory processes in favor of the retrieval of already stored information (pattern completion), to the detriment of encoding new events (pattern separation). Using a novel behavioral paradigm, we investigated the impact of cognitive aging (1) on recognition performance across different levels of stimulus completeness, and (2) on potential response biases. Participants were required to identify previously learned scenes among new ones. Additionally, all stimuli were presented in gradually masked versions to alter stimulus completeness. Both young and older adults performed increasingly poorly as the scenes became less complete, and this decline in performance was more pronounced in elderly participants indicative of a pattern completion deficit. Intriguingly, when novel scenes were shown, only the older adults showed an increased tendency to identify these as familiar scenes. In line with theoretical models, we argue that this reflects an age-related bias towards pattern completion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Explaining the Pattern of CSDP-Operations: Towards a Theoretical Synthesis

    Directory of Open Access Journals (Sweden)

    Tim Haesebrouck

    2015-06-01

    Full Text Available The EU’s Common Security and Defence Policy (CSDP has mainly been used to deploy small-scale operations, which generally did not provide the member states with clear security benefits. This article combines insights from different theories of international relations to explain this disappointing track record. It argues that liberal theories adequately identify the domestic pressures the member states’ governments need to accommodate in the area of crisis management. Constructivism, on its part, properly emphasises the diverging strategic cultures of the member states. Both theories however fail to explain why domestic pressures and diverging strategic cultures lead to small-scale operations. Rational-choice institutionalism does provide a convincing explanation for the latter by drawing attention to the CSDP’s ineffective institutional design. Realism, in turn, is best positioned to explain why the CSDP was not designed more effectively, by emphasising the reluctance of states to transfer sovereignty to international organisations. The article concludes by discussing two measures that could alleviate the impact of the identified impediments on the CSDP’s track record: devising a CSDP-strategy and adapting the consensus rule. However, since the latter is very unlikely in the near future, the CSDP is not expected to develop into a more effective framework for crisis management.

  6. Diffuse scarring alopecia in a female pattern hair loss distribution.

    Science.gov (United States)

    Fergie, Bonnie; Khaira, Gurpreet; Howard, Vicki; de Zwaan, Sally

    2017-02-17

    We describe three cases of hair loss in a female pattern hair loss (FPHL) distribution with histologic features of lichen planopilaris (LPP). All patients had a history of diffuse, gradual hair loss in a Christmas tree pattern that clinically presented as FPHL on gross and dermoscopic examination. Notably, there were no characteristic clinical signs of LPP and no histologic features of FPHL. These cases are most consistent with cicatricial pattern hair loss (CPHL). This relatively new entity is similar to fibrosing alopecia in a pattern distribution (FAPD) in that they are both scarring alopecias confined to a FPHL distribution, but CPHL lacks the clinical signs of perifollicular erythema and perifollicular keratosis seen in FAPD. These three cases may present an early, subtle form of CPHL and will be of interest to clinicians and histopathologists alike. © 2017 The Australasian College of Dermatologists.

  7. Forensic DNA Banding Patterns: How to Simulate & Explain DNA Fingerprinting in a Classroom with No Budget

    Science.gov (United States)

    Christensen, Doug

    2013-01-01

    Understanding how DNA banding patterns in a gel can aid in the conviction or exoneration of suspects and be utilized for positive identification of biological fathers in paternity cases can be intimidating. In reality, the logistics and technology used in such cases are rather straightforward. This exercise is designed for use in high school…

  8. Explaining grass-nutrient patterns in a savanna rangeland of southern Africa

    NARCIS (Netherlands)

    Mutanga, O.; Prins, H.H.T.; Skidmore, A.K.; Wieren, van S.E.; Huizing, H.; Grant, R.; Peel, M.J.S.; Biggs, H.

    2004-01-01

    Aim The search for possible factors influencing the spatial variation of grass quality is an important step towards understanding the distribution of herbivores, as well as a step towards identifying crucial areas for conservation and restoration. A number of studies have shown that grass quality at

  9. Coralligenous habitat: patterns of vertical distribution of macroalgal assemblages

    Directory of Open Access Journals (Sweden)

    Luigi Piazzi

    2011-06-01

    Full Text Available The present study investigates patterns of distribution of macroalgal coralligenous assemblages in relation to depth and evaluates the role of different environmental conditions on these patterns. Two depths (30 and 40 m were investigated off small islands and off continental coasts in order to select two different environmental conditions. Results showed differences between depths in the structure of assemblages around islands, while along the continental coasts these patterns were not evident. Moreover, differences between assemblages related to different environmental conditions were more evident in the shallower zone of distribution of the coralligenous habitat. This correlative study did not allow us to identify any cause-effect relationship, but patterns we detected agree with those of other studies, suggesting that alterations in the environmental conditions may be the cause of the decrease in differences among assemblages developing at different depths and may lead to a higher spatial homogenization and an impoverishment of the whole subtidal system.

  10. On the move: explaining migration patterns in Estonia during the transition period.

    Science.gov (United States)

    Tammaru, T; Sjoberg, O

    1999-01-01

    This paper attempts to explore the migration patterns during the transition period in Estonia. A structuration approach was used to analyze data from the Estonian Statistical Office collected in 1997. Findings show that for migration between urban and rural areas, work-related reasons have been the most important motivating factor in urban growth during the transition period. Also considered are the family and education. In relation to sociodemographic structure of the population, men cite work, while women count family-related reasons, as the main motive for migrating. As to nonregistration, the most significant reason relates to issues of ownership. Because migrants are living in rented housing, it is not possible for them to register even if they desire to do so. Other reasons include "temporary", associated with study and work; "juridical", bureaucratic matters; and "multiple places of residence". This analysis, however, is incomplete because the attitudes and patterns of behavior have only partially or perfunctorily been related to the dramatic changes that have occurred in Estonian society. Proper statistical data are needed to help examine trends at a more disaggregated spatial level.

  11. Streaming driven by sessile microbubbles: Explaining flow patterns and frequency response

    Science.gov (United States)

    Rallabandi, Bhargav; Wang, Cheng; Guo, Lin; Hilgenfeldt, Sascha

    2013-11-01

    Ultrasound excitation of bubbles drives powerful steady streaming flows which have found widespread applications in microfluidics, where bubbles are typically of semicircular cross section and attached to walls of the device (sessile). While bubble-driven streaming in bulk fluid is well understood, this practically relevant case presents additional complexity introduced by the wall and contact lines. We develop an asymptotic theory that takes into account the presence of the wall as well as the oscillation dynamics of the bubble, providing a complete description of the streaming flow as a function only of the driving frequency, the bubble size, and the physical properties of the fluid. We show that the coupling between different bubble oscillation modes sustains the experimentally observed streaming flow vortex pattern over a broad range of frequencies, greatly exceeding the widths of individual mode resonances. Above a threshold frequency, we predict, and observe in experiment, reversal of the flow direction. Our analytical theory can be used to guide the design of microfluidic devices, both in situations where robust flow patterns insensitive to parameter changes are desired (e.g. lab-on-a-chip sorters), and in cases where intentional modulation of the flow field appearance is key (e.g. efficient mixers). Current address: Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology.

  12. Distribution patterns and migratory behavior of Antarctic blue whales

    OpenAIRE

    Thomisch, Karolin

    2016-01-01

    After having been one of the primary targets of commercial whaling during the 20th century, Antarctic blue whales (Balaenoptera musculus intermedia) are still listed as critically endangered by the International Union for Conservation of Nature and many aspects of their distribution and migration patterns remain poorly understood to date. This dissertation investigates spatio-temporal patterns in the (acoustic) presence of Antarctic blue whales in the Atlantic sector of the Southern Ocean and...

  13. Is the diurnal pattern sufficient to explain the intraday variation in volatility? A nonparametric assessment

    DEFF Research Database (Denmark)

    Christensen, Kim; Hounyo, Ulrich; Podolskij, Mark

    is then based on asset returns, which are deflated by a model-free jump- and noise-robust estimate of the seasonal component and therefore homoscedastic under the null. The t-statistic (after pre-averaging and jump-truncation) diverges in the presence of stochastic volatility and has a standard normal...... distribution otherwise. We prove that replacing the true diurnal factor with our estimator does not affect the asymptotic theory. A Monte Carlo simulation also shows this substitution has no discernable impact in finite samples. The test is, however, distorted by small infinite-activity price jumps. To improve...

  14. Interplay of Noisy Gene Expression and Dynamics Explains Patterns of Bacterial Operon Organization

    Science.gov (United States)

    Igoshin, Oleg

    2011-03-01

    Bacterial chromosomes are organized into operons -- sets of genes co-transcribed into polycistronic messenger RNA. Hypotheses explaining the emergence and maintenance of operons include proportional co-regulation, horizontal transfer of intact ``selfish'' operons, emergence via gene duplication, and co-production of physically interacting proteins to speed their association. We hypothesized an alternative: operons can reduce or increase intrinsic gene expression noise in a manner dependent on the post-translational interactions, thereby resulting in selection for or against operons in depending on the network architecture. We devised five classes of two-gene network modules and show that the effects of operons on intrinsic noise depend on class membership. Two classes exhibit decreased noise with co-transcription, two others reveal increased noise, and the remaining one does not show a significant difference. To test our modeling predictions we employed bioinformatic analysis to determine the relationship gene expression noise and operon organization. The results confirm the overrepresentation of noise-minimizing operon architectures and provide evidence against other hypotheses. Our results thereby suggest a central role for gene expression noise in selecting for or maintaining operons in bacterial chromosomes. This demonstrates how post-translational network dynamics may provide selective pressure for organizing bacterial chromosomes, and has practical consequences for designing synthetic gene networks. This work is supported by National Institutes of Health grant 1R01GM096189-01.

  15. Natural aerosols explain seasonal and spatial patterns of Southern Ocean cloud albedo.

    Science.gov (United States)

    McCoy, Daniel T; Burrows, Susannah M; Wood, Robert; Grosvenor, Daniel P; Elliott, Scott M; Ma, Po-Lun; Rasch, Phillip J; Hartmann, Dennis L

    2015-07-01

    Atmospheric aerosols, suspended solid and liquid particles, act as nucleation sites for cloud drop formation, affecting clouds and cloud properties-ultimately influencing the cloud dynamics, lifetime, water path, and areal extent that determine the reflectivity (albedo) of clouds. The concentration N d of droplets in clouds that influences planetary albedo is sensitive to the availability of aerosol particles on which the droplets form. Natural aerosol concentrations affect not only cloud properties themselves but also modulate the sensitivity of clouds to changes in anthropogenic aerosols. It is shown that modeled natural aerosols, principally marine biogenic primary and secondary aerosol sources, explain more than half of the spatiotemporal variability in satellite-observed N d. Enhanced N d is spatially correlated with regions of high chlorophyll a, and the spatiotemporal variability in N d is found to be driven primarily by high concentrations of sulfate aerosol at lower Southern Ocean latitudes (35(o) to 45(o)S) and by organic matter in sea spray aerosol at higher latitudes (45(o) to 55(o)S). Biogenic sources are estimated to increase the summertime mean reflected solar radiation in excess of 10 W m(-2) over parts of the Southern Ocean, which is comparable to the annual mean increases expected from anthropogenic aerosols over heavily polluted regions of the Northern Hemisphere.

  16. Snake co-occurrence patterns are best explained by habitat and hypothesized effects of interspecific interactions.

    Science.gov (United States)

    Steen, David A; McClure, Christopher J W; Brock, Jean C; Craig Rudolph, D; Pierce, Josh B; Lee, James R; Jeffrey Humphries, W; Gregory, Beau B; Sutton, William B; Smith, Lora L; Baxley, Danna L; Stevenson, Dirk J; Guyer, Craig

    2014-01-01

    Snakes often occur in species-rich assemblages, and sympatry is thought to be facilitated primarily by low diet overlap, not interspecific interactions. We selected, a priori, three species pairs consisting of species that are morphologically and taxonomically similar and may therefore be likely to engage in interspecific, consumptive competition. We then examined a large-scale database of snake detection/nondetection data and used occupancy modelling to determine whether these species occur together more or less frequently than expected by chance while accounting for variation in detection probability among species and incorporating important habitat categories in the models. For some snakes, we obtained evidence that the probabilities that habitat patches are used are influenced by the presence of potentially competing congeneric species. Specifically, timber rattlesnakes (Crotalus horridus) were less likely than expected by chance to use areas that also contained eastern diamond-backed rattlesnakes (Crotalus adamanteus) when the proportion of evergreen forest was relatively high. Otherwise, they occurred together more often than expected by chance. Complex relationships were revealed between habitat use, detection probabilities and occupancy probabilities of North American racers (Coluber constrictor) and coachwhips (Coluber flagellum) that indicated the probability of competitive exclusion increased with increasing area of grassland habitat, although there was some model uncertainty. Cornsnakes (Pantherophis guttatus or Pantherophis slowinskii) and ratsnakes (Pantherophis alleghaniensis, Pantherophis spiloides, or Pantherophis obsoletus) exhibited differences in habitat selection, but we obtained no evidence that patterns of use for this species pair were influenced by current interspecific interactions. Overall, our results are consistent with the hypothesis that competitive interactions influence snake assemblage composition; the strength of these effects was

  17. Field measurements give biased estimates of functional response parameters, but help explain foraging distributions

    NARCIS (Netherlands)

    Duijns, S.; Knot, I.E.; Piersma, T.; van Gils, J.A.

    2015-01-01

    1.Mechanistic insights and predictive understanding of the spatial distributions of foragers are typically derived by fitting either field measurements on intake rates and food abundance, or observations from controlled experiments, to functional response models. It has remained unclear, however,

  18. Spatial climate patterns explain negligible variation in strength of compensatory density feedbacks in birds and mammals.

    Directory of Open Access Journals (Sweden)

    Salvador Herrando-Pérez

    Full Text Available The use of long-term population data to separate the demographic role of climate from density-modified demographic processes has become a major topic of ecological investigation over the last two decades. Although the ecological and evolutionary mechanisms that determine the strength of density feedbacks are now well understood, the degree to which climate gradients shape those processes across taxa and broad spatial scales remains unclear. Intuitively, harsh or highly variable environmental conditions should weaken compensatory density feedbacks because populations are hypothetically unable to achieve or maintain densities at which social and trophic interactions (e.g., competition, parasitism, predation, disease might systematically reduce population growth. Here we investigate variation in the strength of compensatory density feedback, from long-term time series of abundance over 146 species of birds and mammals, in response to spatial gradients of broad-scale temperature precipitation variables covering 97 localities in 28 countries. We use information-theoretic metrics to rank phylogenetic generalized least-squares regression models that control for sample size (time-series length and phylogenetic non-independence. Climatic factors explained < 1% of the remaining variation in density-feedback strength across species, with the highest non-control, model-averaged effect sizes related to extreme precipitation variables. We could not link our results directly to other published studies, because ecologists use contrasting responses, predictors and statistical approaches to correlate density feedback and climate--at the expense of comparability in a macroecological context. Censuses of multiple populations within a given species, and a priori knowledge of the spatial scales at which density feedbacks interact with climate, seem to be necessary to determine cross-taxa variation in this phenomenon. Despite the availability of robust modelling tools

  19. Spatial climate patterns explain negligible variation in strength of compensatory density feedbacks in birds and mammals.

    Science.gov (United States)

    Herrando-Pérez, Salvador; Delean, Steven; Brook, Barry W; Cassey, Phillip; Bradshaw, Corey J A

    2014-01-01

    The use of long-term population data to separate the demographic role of climate from density-modified demographic processes has become a major topic of ecological investigation over the last two decades. Although the ecological and evolutionary mechanisms that determine the strength of density feedbacks are now well understood, the degree to which climate gradients shape those processes across taxa and broad spatial scales remains unclear. Intuitively, harsh or highly variable environmental conditions should weaken compensatory density feedbacks because populations are hypothetically unable to achieve or maintain densities at which social and trophic interactions (e.g., competition, parasitism, predation, disease) might systematically reduce population growth. Here we investigate variation in the strength of compensatory density feedback, from long-term time series of abundance over 146 species of birds and mammals, in response to spatial gradients of broad-scale temperature precipitation variables covering 97 localities in 28 countries. We use information-theoretic metrics to rank phylogenetic generalized least-squares regression models that control for sample size (time-series length) and phylogenetic non-independence. Climatic factors explained < 1% of the remaining variation in density-feedback strength across species, with the highest non-control, model-averaged effect sizes related to extreme precipitation variables. We could not link our results directly to other published studies, because ecologists use contrasting responses, predictors and statistical approaches to correlate density feedback and climate--at the expense of comparability in a macroecological context. Censuses of multiple populations within a given species, and a priori knowledge of the spatial scales at which density feedbacks interact with climate, seem to be necessary to determine cross-taxa variation in this phenomenon. Despite the availability of robust modelling tools, the appropriate

  20. Spatial Climate Patterns Explain Negligible Variation in Strength of Compensatory Density Feedbacks in Birds and Mammals

    Science.gov (United States)

    Herrando-Pérez, Salvador; Delean, Steven; Brook, Barry W.; Cassey, Phillip; Bradshaw, Corey J. A.

    2014-01-01

    The use of long-term population data to separate the demographic role of climate from density-modified demographic processes has become a major topic of ecological investigation over the last two decades. Although the ecological and evolutionary mechanisms that determine the strength of density feedbacks are now well understood, the degree to which climate gradients shape those processes across taxa and broad spatial scales remains unclear. Intuitively, harsh or highly variable environmental conditions should weaken compensatory density feedbacks because populations are hypothetically unable to achieve or maintain densities at which social and trophic interactions (e.g., competition, parasitism, predation, disease) might systematically reduce population growth. Here we investigate variation in the strength of compensatory density feedback, from long-term time series of abundance over 146 species of birds and mammals, in response to spatial gradients of broad-scale temperature precipitation variables covering 97 localities in 28 countries. We use information-theoretic metrics to rank phylogenetic generalized least-squares regression models that control for sample size (time-series length) and phylogenetic non-independence. Climatic factors explained < 1% of the remaining variation in density-feedback strength across species, with the highest non-control, model-averaged effect sizes related to extreme precipitation variables. We could not link our results directly to other published studies, because ecologists use contrasting responses, predictors and statistical approaches to correlate density feedback and climate – at the expense of comparability in a macroecological context. Censuses of multiple populations within a given species, and a priori knowledge of the spatial scales at which density feedbacks interact with climate, seem to be necessary to determine cross-taxa variation in this phenomenon. Despite the availability of robust modelling tools, the

  1. Mean annual precipitation explains spatiotemporal patterns of Cenozoic mammal beta diversity and latitudinal diversity gradients in North America.

    Directory of Open Access Journals (Sweden)

    Danielle Fraser

    Full Text Available Spatial diversity patterns are thought to be driven by climate-mediated processes. However, temporal patterns of community composition remain poorly studied. We provide two complementary analyses of North American mammal diversity, using (i a paleontological dataset (2077 localities with 2493 taxon occurrences spanning 21 discrete subdivisions of the Cenozoic based on North American Land Mammal Ages (36 Ma--present, and (ii climate space model predictions for 744 extant mammals under eight scenarios of future climate change. Spatial variation in fossil mammal community structure (β diversity is highest at intermediate values of continental mean annual precipitation (MAP estimated from paleosols (∼ 450 mm/year and declines under both wetter and drier conditions, reflecting diversity patterns of modern mammals. Latitudinal gradients in community change (latitudinal turnover gradients, aka LTGs increase in strength through the Cenozoic, but also show a cyclical pattern that is significantly explained by MAP. In general, LTGs are weakest when continental MAP is highest, similar to modern tropical ecosystems in which latitudinal diversity gradients are weak or undetectable. Projections under modeled climate change show no substantial change in β diversity or LTG strength for North American mammals. Our results suggest that similar climate-mediated mechanisms might drive spatial and temporal patterns of community composition in both fossil and extant mammals. We also provide empirical evidence that the ecological processes on which climate space models are based are insufficient for accurately forecasting long-term mammalian response to anthropogenic climate change and inclusion of historical parameters may be essential.

  2. Mean annual precipitation explains spatiotemporal patterns of Cenozoic mammal beta diversity and latitudinal diversity gradients in North America.

    Science.gov (United States)

    Fraser, Danielle; Hassall, Christopher; Gorelick, Root; Rybczynski, Natalia

    2014-01-01

    Spatial diversity patterns are thought to be driven by climate-mediated processes. However, temporal patterns of community composition remain poorly studied. We provide two complementary analyses of North American mammal diversity, using (i) a paleontological dataset (2077 localities with 2493 taxon occurrences) spanning 21 discrete subdivisions of the Cenozoic based on North American Land Mammal Ages (36 Ma--present), and (ii) climate space model predictions for 744 extant mammals under eight scenarios of future climate change. Spatial variation in fossil mammal community structure (β diversity) is highest at intermediate values of continental mean annual precipitation (MAP) estimated from paleosols (∼ 450 mm/year) and declines under both wetter and drier conditions, reflecting diversity patterns of modern mammals. Latitudinal gradients in community change (latitudinal turnover gradients, aka LTGs) increase in strength through the Cenozoic, but also show a cyclical pattern that is significantly explained by MAP. In general, LTGs are weakest when continental MAP is highest, similar to modern tropical ecosystems in which latitudinal diversity gradients are weak or undetectable. Projections under modeled climate change show no substantial change in β diversity or LTG strength for North American mammals. Our results suggest that similar climate-mediated mechanisms might drive spatial and temporal patterns of community composition in both fossil and extant mammals. We also provide empirical evidence that the ecological processes on which climate space models are based are insufficient for accurately forecasting long-term mammalian response to anthropogenic climate change and inclusion of historical parameters may be essential.

  3. Legacy introductions and climatic variation explain spatiotemporal patterns of invasive hybridization in a native trout

    Science.gov (United States)

    Muhlfeld, Clint C.; Kovach, Ryan P.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David A.; Shepard, Bradley B.; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W.

    2017-01-01

    Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large, multi-decade genetics dataset (N = 582 sites, 12,878 individuals) with high-resolution climate predictions and extensive stocking records, we evaluate the spatiotemporal dynamics of hybridization between native cutthroat trout and invasive rainbow trout, the world’s most widely introduced invasive fish, across the northern Rocky Mountains of the United States. Historical effects of stocking and contemporary patterns of climatic variation were strongly related to the spread of hybridization across space and time. The probability of occurrence, extent of, and temporal changes in hybridization increased at sites in close proximity to historical stocking locations with greater rainbow trout propagule pressure, warmer water temperatures, and lower spring precipitation. Although locations with warmer water temperatures were more prone to hybridization, cold sites were not protected from invasion; 58% of hybridized sites had cold mean summer water temperatures (climate change on biodiversity must be analyzed in the context of historical human impacts that set ecological and evolutionary trajectories.

  4. Reciprocal Exchange Patterned by Market Forces Helps Explain Cooperation in a Small-Scale Society.

    Science.gov (United States)

    Jaeggi, Adrian V; Hooper, Paul L; Beheim, Bret A; Kaplan, Hillard; Gurven, Michael

    2016-08-22

    Social organisms sometimes depend on help from reciprocating partners to solve adaptive problems [1], and individual cooperation strategies should aim to offer high supply commodities at low cost to the donor in exchange for high-demand commodities with large return benefits [2, 3]. Although such market dynamics have been documented in some animals [4-7], naturalistic studies of human cooperation are often limited by focusing on single commodities [8]. We analyzed cooperation in five domains (meat sharing, produce sharing, field labor, childcare, and sick care) among 2,161 household dyads of Tsimane' horticulturalists, using Bayesian multilevel models and information-theoretic model comparison. Across domains, the best-fit models included kinship and residential proximity, exchanges in kind and across domains, measures of supply and demand and their interactions with exchange, and household-specific exchange slopes. In these best models, giving, receiving, and reciprocating were to some extent shaped by market forces, and reciprocal exchange across domains had a strong partial effect on cooperation independent of more exogenous factors like kinship and proximity. Our results support the view that reciprocal exchange can provide a reliable solution to adaptive problems [8-11]. Although individual strategies patterned by market forces may generate gains from trade in any species [3], humans' slow life history and skill-intensive foraging niche favor specialization and create interdependence [12, 13], thus stabilizing cooperation and fostering divisions of labor even in informal economies [14, 15]. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Long-term climate and competition explain forest mortality patterns under extreme drought.

    Science.gov (United States)

    Young, Derek J N; Stevens, Jens T; Earles, J Mason; Moore, Jeffrey; Ellis, Adam; Jirka, Amy L; Latimer, Andrew M

    2017-01-01

    Rising temperatures are amplifying drought-induced stress and mortality in forests globally. It remains uncertain, however, whether tree mortality across drought-stricken landscapes will be concentrated in particular climatic and competitive environments. We investigated the effects of long-term average climate [i.e. 35-year mean annual climatic water deficit (CWD)] and competition (i.e. tree basal area) on tree mortality patterns, using extensive aerial mortality surveys conducted throughout the forests of California during a 4-year statewide extreme drought lasting from 2012 to 2015. During this period, tree mortality increased by an order of magnitude, typically from tens to hundreds of dead trees per km2 , rising dramatically during the fourth year of drought. Mortality rates increased independently with average CWD and with basal area, and they increased disproportionately in areas that were both dry and dense. These results can assist forest managers and policy-makers in identifying the most drought-vulnerable forests across broad geographic areas. © 2016 John Wiley & Sons Ltd/CNRS.

  6. Dietary patterns explaining differences in bone mineral density and hip structure in the elderly: the Rotterdam Study.

    Science.gov (United States)

    de Jonge, Ester Al; Kiefte-de Jong, Jessica C; Hofman, Albert; Uitterlinden, André G; Kieboom, Brenda Ct; Voortman, Trudy; Franco, Oscar H; Rivadeneira, Fernando

    2017-01-01

    Evidence on the association between dietary patterns, measures of hip bone geometry, and subsequent fracture risk are scarce. The objective of this study was to evaluate whether dietary patterns that explain most variation in bone mineral density (BMD) and hip bone geometry are associated with fracture risk. We included 4028 subjects aged ≥55 y from the Rotterdam study. Intake of 28 food groups was assessed with the use of food-frequency questionnaires. BMD, bone width, section modulus (SM; reflecting bending strength) and cortical buckling ratio (BR; reflecting bone instability) were measured with the use of dual-energy X-ray absorptiometry. BMD and geometry-specific dietary patterns were identified with the use of reduced rank regression. Fracture data were reported by general practitioners (median follow-up 14.8 y). We identified 4 dietary patterns. Of the 4, we named 2 patterns "fruit, vegetables, and dairy" and "sweets, animal fat, and low meat," respectively. These 2 patterns were used for further analysis. Independently of confounders, adherence to the fruit, vegetables, and dairy pattern was associated with high BMD, high SM, low BR, and low risk of fractures [HR (95% CI) for osteoporotic fractures: 0.90 (0.83, 0.96); for hip fractures: 0.85 (0.81, 0.89) per z score of dietary pattern adherence]. Adherence to the sweets, animal fat, and low meat pattern was associated with high bone width, high SM, high BR, and high risk of fractures [HR (95% CI) for osteoporotic fractures: 1.08 (1.00, 1.06); for hip fractures: 1.06 (1.02, 1.12) per z score]. The fruit, vegetables, and dairy pattern might be associated with lower fracture risk because of high BMD, high bending strength, and more stable bones. The sweets, animal fat, and low meat pattern might be associated with higher fracture risk because of widened, unstable bones, independently of BMD. Dietary recommendations associated with bone geometry in addition to BMD might influence risk of fractures. © 2017

  7. Does Bilateral Market and Financial Integration Explains International Co-Movement Patterns1

    Directory of Open Access Journals (Sweden)

    Mobeen Ur Rehman

    2016-05-01

    Full Text Available This study aims to explore the relationship between market integration, foreign portfolio equity holding and inflation rates on international stock market linkages between Pakistan and India. To measure stock equity interlinkage, we constructed international co-movement index through rolling beta estimation. Market integration variable between these two countries is constructed using the International Capital Asset Pricing Model (ICAPM. To check the impact of market integration, foreign portfolio equity holding and inflation rate on Pakistan-Indian stock market co-movement, we applied autoregressive distributed lag (ARDL estimation. ARDL estimation is applied due to different stationarity levels of the included variables. The level of convergence speed is measured by the introduction of error correction term (ECT followed by variance decomposition analysis. Results of the study indicated presence of long term relationship among the included variables along with significance variance in bilateral co-movement due to inflation rate differential. The significance of inflation rate differences between these two countries are in accordance with portfolio balance theory stating that investors possess information about the macroeconomic variables thereby readjusting their portfolios for effective diversification.

  8. Complex and changing patterns of natural selection explain the evolution of the human hip.

    Science.gov (United States)

    Grabowski, Mark; Roseman, Charles C

    2015-08-01

    Causal explanations for the dramatic changes that occurred during the evolution of the human hip focus largely on selection for bipedal function and locomotor efficiency. These hypotheses rest on two critical assumptions. The first-that these anatomical changes served functional roles in bipedalism-has been supported in numerous analyses showing how postcranial changes likely affected locomotion. The second-that morphological changes that did play functional roles in bipedalism were the result of selection for that behavior-has not been previously explored and represents a major gap in our understanding of hominin hip evolution. Here we use evolutionary quantitative genetic models to test the hypothesis that strong directional selection on many individual aspects of morphology was responsible for the large differences observed across a sample of fossil hominin hips spanning the Plio-Pleistocene. Our approach uses covariance among traits and the differences between relatively complete fossils to estimate the net selection pressures that drove the major transitions in hominin hip evolution. Our findings show a complex and changing pattern of natural selection drove hominin hip evolution, and that many, but not all, traits hypothesized to play functional roles in bipedalism evolved as a direct result of natural selection. While the rate of evolutionary change for all transitions explored here does not exceed the amount expected if evolution was occurring solely through neutral processes, it was far above rates of evolution for morphological traits in other mammalian groups. Given that stasis is the norm in the mammalian fossil record, our results suggest that large shifts in the adaptive landscape drove hominin evolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Normal plantar weight distribution pattern and its variations with ...

    African Journals Online (AJOL)

    Normal plantar weight distribution pattern and its variations with change of functional position and its comparison with patients of knee osteoarthritis. ... The participants in group-1 had no knee complaint and those in group-2 had diagnosis of early knee osteoarthritis. Independent test was used for the statistical analysis.

  10. Sparse Distribution Pattern Of Some Plant Species In Two ...

    African Journals Online (AJOL)

    This study analysed species diversity and distribution patterns on two afromontane rain forests of the eastern Arc Mountains of Tanzania in the west Usambaras and Ulugurus to assess any possible threats to biodiversity conservation in this region. A hundred sample plots (0.02 ha) were established on each of the two ...

  11. Photosynthate distribution patterns in cherrybark oak seedling sprouts

    Science.gov (United States)

    Brian Roy Lockhart; John D. Hodges; Emile S. Gardiner; Andrew W. Ezell

    2003-01-01

    Summary We used 14C tracers to determine photosynthate distribution in cherrybark oak (Quercus pagoda Raf.) seedling sprouts following release from competing mid-story vegetation. Fall acquisition of labeled photosynthates by seedlings followed expected source--sink patterns, with root and basal stem tissues...

  12. Heterogeneity of DNA Distribution Pattern in Renal Tumours

    Directory of Open Access Journals (Sweden)

    Hans Nenning

    1997-01-01

    Full Text Available The presence of intratumoural heterogeneity in DNA distribution patterns has been accepted. However, most previous studies have not taken this fact into consideration. The value of DNA cytometry depends on its reproducibility. This could be influenced by heterogeneity failure. The aim of the present study is to evaluate intratumoural heterogeneity in renal cell cancer.

  13. Pattern and distribution of sexually transmitted diseases in Lagos ...

    African Journals Online (AJOL)

    This study was designed to investigate the pattern and distribution of sexually transmitted diseases. A total of 134 adult Subjects (89 women and 45 men) presenting with various signs and symptoms of lower genital tract infections were recruited for the study. Samples such as urine, urethral swab, high vaginal swab and/or ...

  14. Anomalous patterns of formation and distribution of the brachial ...

    African Journals Online (AJOL)

    block Background: Structural variations in the patterns of formation and distribution of the brachial plexus have drawn attentions both in anatomy and anaesthesia. Method: An observational study. Results: The brachial plexus was carefully inspected in both the right and left arms in 90 Nigerian cadavers, comprising of 74 ...

  15. Pattern Recognition for Reliability Assessment of Water Distribution Networks

    NARCIS (Netherlands)

    Trifunović, N.

    2012-01-01

    The study presented in this manuscript investigates the patterns that describe reliability of water distribution networks focusing to the node connectivity, energy balance, and economics of construction, operation and maintenance. A number of measures to evaluate the network resilience has been

  16. A Spatial Analysis of Population Distribution and Housing Patterns ...

    African Journals Online (AJOL)

    The paper examined the spatial patterns of population distribution andhousing in Abraka in Delta State of Nigeria. Population is a vital componentof development in any country including Nigeria. Housing is a physical andsocial necessity of life which holds a place of strategic importance indevelopment. However, the high ...

  17. spatial patterns of zooplankton distribution and abundance in ...

    African Journals Online (AJOL)

    nb

    §The writing of this paper was completed posthumously. ABSTRACT. Spatial patterns and ... consideration because of its changes in limnological conditions caused by nutrients inputs and ..... distribution significantly positively. Table 1: Variation of water quality parameters (mean ± standard error) measured during the study.

  18. Distribution Pattern of Healthcare Facilities in Osun State, Nigeria ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    that the new wave of democratization that started in the country in 1999 has succeeded in achieving a wider spread of healthcare facilities and personnel in the state, thus contributing to the quality of life of the citizenry, especially those in the rural areas. Though the observed pattern of distribution of healthcare facilities and.

  19. Explaining individual variation in patterns of mass loss in breeding birds

    Directory of Open Access Journals (Sweden)

    Cuthill Innes C

    2006-05-01

    Full Text Available Abstract Background Studies of birds have a disproportionate representation in the literature on life-history evolution, because of the (apparent ease with which the costs and benefits can be quantified and manipulated. During reproduction, birds frequently show a highly conserved pattern of mass change and changes in mass loss during breeding have been widely considered to be a valid short-term measure of the costs of reproduction. Experimental manipulations of the breeding attempts of birds usually argue that the presence of a response shows that a cost of reproduction exists, but there is little consensus as to how the size of these costs can be measured. Results We model this mass loss by considering how a parent can maximise its lifetime reproductive success, using a theoretical framework that is particularly suited to modelling parental care in altricial birds. If lifetime reproductive success is taken to be the sum of a parent's current and future reproductive success, we show that the exact forms of these components will influence the optimal amount of mass a parent should lose. In particular, we demonstrate that the shape of the relationship between parental investment and chick survival will lead to differing degrees of investment between parents of different initial qualities: parents with initially high levels of energy reserves could conceivably invested a lesser, similar or greater amount of resources than parents with initially low reserves, and these initially 'heavy' parents could potentially end up being lighter than the initially 'lighter' individuals. Conclusion We argue that it is difficult to make predictions about the dependence of a parent's final mass on its initial mass, and therefore mass loss should only be used as a short-term measure of the costs of reproduction with caution. The model demonstrates that we require a better understanding of the relationship between mass loss and both current and future reproductive

  20. Inhomogeneity Based Characterization of Distribution Patterns on the Plasma Membrane.

    Directory of Open Access Journals (Sweden)

    Laura Paparelli

    2016-09-01

    Full Text Available Cell surface protein and lipid molecules are organized in various patterns: randomly, along gradients, or clustered when segregated into discrete micro- and nano-domains. Their distribution is tightly coupled to events such as polarization, endocytosis, and intracellular signaling, but challenging to quantify using traditional techniques. Here we present a novel approach to quantify the distribution of plasma membrane proteins and lipids. This approach describes spatial patterns in degrees of inhomogeneity and incorporates an intensity-based correction to analyze images with a wide range of resolutions; we have termed it Quantitative Analysis of the Spatial distributions in Images using Mosaic segmentation and Dual parameter Optimization in Histograms (QuASIMoDOH. We tested its applicability using simulated microscopy images and images acquired by widefield microscopy, total internal reflection microscopy, structured illumination microscopy, and photoactivated localization microscopy. We validated QuASIMoDOH, successfully quantifying the distribution of protein and lipid molecules detected with several labeling techniques, in different cell model systems. We also used this method to characterize the reorganization of cell surface lipids in response to disrupted endosomal trafficking and to detect dynamic changes in the global and local organization of epidermal growth factor receptors across the cell surface. Our findings demonstrate that QuASIMoDOH can be used to assess protein and lipid patterns, quantifying distribution changes and spatial reorganization at the cell surface. An ImageJ/Fiji plugin of this analysis tool is provided.

  1. Biotic and abiotic variables show little redundancy in explaining tree species distributions

    DEFF Research Database (Denmark)

    Meier, Elaine S.; Kienast, Felix; Pearman, Peter B.

    2010-01-01

    Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic var...

  2. Sex-specific winter distribution in a sexually dimorphic shorebird is explained by resource partitioning

    NARCIS (Netherlands)

    Duijns, S.; van Gils, J.A.; Spaans, B.; ten Horn, J.; Brugge, M.; Piersma, T.

    2014-01-01

    Sexual size dimorphism (SSD) implies correlated differences in energetic requirements and feeding opportunities, such that sexes will face different trade-offs in habitat selection. In seasonal migrants, this could result in a differential spatial distribution across the wintering range. To identify

  3. Land use explains the distribution of threatened New World amphibians better than climate.

    Science.gov (United States)

    Brum, Fernanda Thiesen; Gonçalves, Larissa Oliveira; Cappelatti, Laura; Carlucci, Marcos Bergmann; Debastiani, Vanderlei Júlio; Salengue, Elisa Viana; dos Santos Seger, Guilherme Dubal; Both, Camila; Bernardo-Silva, Jorge Sebastião; Loyola, Rafael Dias; da Silva Duarte, Leandro

    2013-01-01

    We evaluated the direct and indirect influence of climate, land use, phylogenetic structure, species richness and endemism on the distribution of New World threatened amphibians. We used the WWF's New World ecoregions, the WWFs amphibian distributional data and the IUCN Red List Categories to obtain the number of threatened species per ecoregion. We analyzed three different scenarios urgent, moderate, and the most inclusive scenario. Using path analysis we evaluated the direct and indirect effects of climate, type of land use, phylogenetic structure, richness and endemism on the number of threatened amphibians in New World ecoregions. In all scenarios we found strong support for direct influences of endemism, the cover of villages and species richness on the number of threatened species in each ecoregion. The proportion of wild area had indirect effects in the moderate and the most inclusive scenario. Phylogenetic composition was important in determining the species richness and endemism in each ecoregion. Climate variables had complex and indirect effects on the number of threatened species. Land use has a more direct influence than climate in determining the distribution of New World threatened amphibians. Independently of the scenario analyzed, the main variables influencing the distribution of threatened amphibians were consistent, with endemism having the largest magnitude path coefficient. The importance of phylogenetic composition could indicate that some clades may be more threatened than others, and their presence increases the number of threatened species. Our results highlight the importance of man-made land transformation, which is a local variable, as a critical factor underlying the distribution of threatened amphibians at a biogeographic scale.

  4. Macroecological patterns in the distribution of marine phytoplankton

    DEFF Research Database (Denmark)

    Mousing, Erik Askov

    and community size structure at the global scale. The statistical approach applied indicated that different nutrients were, apparently, co-limiting the examined phytoplankton processes in different regions of the world’s oceans. It is also shown that there is a strong increase in both phytoplankton total...... for predicting future ocean function. This PhD thesis investigates and describes macroecological patterns in the distribution and diversity of marine phytoplankton. The primary focus has been to describe macroecological patterns in phytoplankton total biomass and community structure and relate these patterns...... are presented as five research chapters shaped as manuscripts. In Manuscript I, the macroecological patterns in phytoplankton community size structure were investigated in relation to temperature and inorganic nutrient concentrations. Although temperature has been shown to directly affect phytoplankton size...

  5. How can individual differences in autobiographical memory distributions of older adults be explained?

    Science.gov (United States)

    Wolf, Tabea; Zimprich, Daniel

    2016-10-01

    The reminiscence bump phenomenon has frequently been reported for the recall of autobiographical memories. The present study complements previous research by examining individual differences in the distribution of word-cued autobiographical memories. More importantly, we introduce predictor variables that might account for individual differences in the mean (location) and the standard deviation (scale) of individual memory distributions. All variables were derived from different theoretical accounts for the reminiscence bump phenomenon. We used a mixed location-scale logitnormal model, to analyse the 4602 autobiographical memories reported by 118 older participants. Results show reliable individual differences in the location and the scale. After controlling for age and gender, individual proportions of first-time experiences and individual proportions of positive memories, as well as the ratings on Openness to new Experiences and Self-Concept Clarity accounted for 29% of individual differences in location and 42% of individual differences in scale of autobiographical memory distributions. Results dovetail with a life-story account for the reminiscence bump which integrates central components of previous accounts.

  6. Linking canopy leaf area and light environments with tree size distributions to explain Amazon forest demography.

    Science.gov (United States)

    Stark, Scott C; Enquist, Brian J; Saleska, Scott R; Leitold, Veronika; Schietti, Juliana; Longo, Marcos; Alves, Luciana F; Camargo, Plinio B; Oliveira, Raimundo C

    2015-07-01

    Forest biophysical structure - the arrangement and frequency of leaves and stems - emerges from growth, mortality and space filling dynamics, and may also influence those dynamics by structuring light environments. To investigate this interaction, we developed models that could use LiDAR remote sensing to link leaf area profiles with tree size distributions, comparing models which did not (metabolic scaling theory) and did allow light to influence this link. We found that a light environment-to-structure link was necessary to accurately simulate tree size distributions and canopy structure in two contrasting Amazon forests. Partitioning leaf area profiles into size-class components, we found that demographic rates were related to variation in light absorption, with mortality increasing relative to growth in higher light, consistent with a light environment feedback to size distributions. Combining LiDAR with models linking forest structure and demography offers a high-throughput approach to advance theory and investigate climate-relevant tropical forest change. © 2015 John Wiley & Sons Ltd/CNRS.

  7. Distribution patterns and coincidence of sesamoid bones at metatarsophalangeal joints.

    Science.gov (United States)

    Sun, Tao; Zhao, Haitao; Wang, Lingxiang; Wu, Wenjuan; Hu, Wenhai

    2017-04-01

    Our aim was to identify the incidence and distribution of sesamoid bones plantar to the metatarsophalangeal (MTP) joints in adults, and to evaluate patterns of coincidence among these sesamoid bones. We conducted a retrospective review of 7949 plain radiographs obtained from patients evaluated for foot trauma or symptomology. Associations between the distributions of MTP sesamoid bones as well as the association of age, sex, and laterality with identified prevalence, distribution, and coincidence were evaluated using Spearman's correlation coefficient. Overall, 17,060 sesamoid bones were identified for 9005 MTP joints, with 16 distinctive distribution patterns. Among possible patterns, we identified a prevalence rate of complete absence of MTP sesamoid of 0.04 %, of a single sesamoid at the hallux of 89.08 % of radiographs; and of sesamoid at ≥2 MTP joints of 10.88 %. The presence of a sesamoid at the hallux was consistent, and was not correlated with the presence or absence of a sesamoid bone at one of the other MTP joints (P > 0.05). However, there was a positive correlation between the presence and absence of sesamoid bones at any two of the other four MTP joints (P joints with sesamoids (P < 0.001). Information from this study would assist clinicians in the diagnosis of patients presenting with pain and discomfort of the foot after trauma and overuse, as well as contribute a robust data set for research in forensic science and anthropology.

  8. Optimal pattern distributions in Rete-based production systems

    Science.gov (United States)

    Scott, Stephen L.

    1994-01-01

    Since its introduction into the AI community in the early 1980's, the Rete algorithm has been widely used. This algorithm has formed the basis for many AI tools, including NASA's CLIPS. One drawback of Rete-based implementation, however, is that the network structures used internally by the Rete algorithm make it sensitive to the arrangement of individual patterns within rules. Thus while rules may be more or less arbitrarily placed within source files, the distribution of individual patterns within these rules can significantly affect the overall system performance. Some heuristics have been proposed to optimize pattern placement, however, these suggestions can be conflicting. This paper describes a systematic effort to measure the effect of pattern distribution on production system performance. An overview of the Rete algorithm is presented to provide context. A description of the methods used to explore the pattern ordering problem area are presented, using internal production system metrics such as the number of partial matches, and coarse-grained operating system data such as memory usage and time. The results of this study should be of interest to those developing and optimizing software for Rete-based production systems.

  9. Diversity and distribution patterns in high southern latitude sponges.

    Directory of Open Access Journals (Sweden)

    Rachel V Downey

    Full Text Available Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ∼43%, with a higher level for the class Hexactinellida (68%. Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent

  10. Diversity and Distribution Patterns in High Southern Latitude Sponges

    Science.gov (United States)

    Downey, Rachel V.; Griffiths, Huw J.; Linse, Katrin; Janussen, Dorte

    2012-01-01

    Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ∼43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity. PMID

  11. Possible mechanism for explaining the origin and size distribution of Martian hematite spherules

    Science.gov (United States)

    Misra, Anupam K.; Acosta-Maeda, Tayro E.; Scott, Edward R. D.; Sharma, Shiv K.

    2014-03-01

    Mysterious hematite spherules, also known as “blueberries”, observed at Meridiani Planum on Mars have been widely accepted as concretions which are formed by precipitation of aqueous fluids. One of the biggest mysteries is that all observed Martian blueberries are limited in size with maximum diameter of 6.2 mm. In contrast, terrestrial concretions are not size limited. In this article, we discuss significant differences between Martian blueberries and Earth concretion analogs. Puzzling observations from Mars Exploration Rovers Opportunity and Spirit suggest that the spherules may not be concretions but are cosmic spherules formed by ablation of meteorites. The perfect spherical shape of spherules, their observed size limit, and all other physical properties are easily explained by a meteorite ablation model. Evidence that some of these spherules are only few years old strongly constrains concretion and other growth mechanisms related to aqueous processes that require the existence of water on Mars in its recent history. The large number of hematite spherules in Meridiani Planum may be due to a big rare iron meteorite impact event in this region sometime in the past.

  12. Can salinity-induced mortality explain larval vertical distribution with respect to a halocline?

    Science.gov (United States)

    Sameoto, Jessica A; Metaxas, Anna

    2008-06-01

    For the larvae of two echinoderm species that coexist in Atlantic Canada (bipinnaria of the sea star Asterias rubens and 4- and 6-arm echinoplutei of the sea urchin Strongylocentrotus droebachiensis), we examined the effect of short- and long-term exposure to salinity (ranging from 18 to 35) on the probability of larval survival in laboratory experiments. We also related larval vertical distributions in response to sharp haloclines generated in the laboratory to survival probability in the salinity of different layers in the water column. For both species and developmental stages, survival probability decreased with decreasing salinity, and a salinity range of 24-27 emerged as the critical threshold for larval tolerance. The relationship between the proportion of larvae that crossed a halocline into the top water layer and the survival probability of larvae in the salinity of that layer was significant for both species. Interestingly, the shape of this response was species-specific but not stage-specific for S. droebachiensis. Our findings suggest that larval avoidance of low-salinity water layers may be an adaptive behavior that increases survival and indirectly influences larval distribution.

  13. Scanning patterns of faces do not explain impaired emotion recognition in Huntington Disease: Evidence for a high level mechanism

    Directory of Open Access Journals (Sweden)

    Marieke evan Asselen

    2012-02-01

    Full Text Available Previous studies in patients with amygdala lesions suggested that deficits in emotion recognition might be mediated by impaired scanning patterns of faces. Here we investigated whether scanning patterns also contribute to the selective impairment in recognition of disgust in Huntington disease (HD. To achieve this goal, we recorded eye movements during a two-alternative forced choice emotion recognition task. HD patients in presymptomatic (n=16 and symptomatic (n=9 disease stages were tested and their performance was compared to a control group (n=22. In our emotion recognition task, participants had to indicate whether a face reflected one of six basic emotions. In addition, and in order to define whether emotion recognition was altered when the participants were forced to look at a specific component of the face, we used a second task where only limited facial information was provided (eyes/mouth in partially masked faces. Behavioural results showed no differences in the ability to recognize emotions between presymptomatic gene carriers and controls. However, an emotion recognition deficit was found for all 6 basic emotion categories in early stage HD. Analysis of eye movement patterns showed that patient and controls used similar scanning strategies. Patterns of deficits were similar regardless of whether parts of the faces were masked or not, thereby confirming that selective attention to particular face parts is not underlying the deficits. These results suggest that the emotion recognition deficits in symptomatic HD patients cannot be explained by impaired scanning patterns of faces. Furthermore, no selective deficit for recognition of disgust was found in presymptomatic HD patients.

  14. Distribution pattern of benthic invertebrates in Danish estuaries

    DEFF Research Database (Denmark)

    Kristensen, Erik; Delefosse, Matthieu; Quintana, Cintia Organo

    2013-01-01

    distribution of 9 dominating benthic invertebrate species from two study areas, the estuaries Odense Fjord and Roskilde Fjord, Denmark. The slope (b) obtained fromthe power relationship of sample variance (s2) versusmean (μ) appears to be species-specific and independent of location and time. It ranges from...... factors such as behavior and intraspecific interactions. Thus, at the examined spatial scale, the more intense intraspecific interactions (e.g. territoriality) cause less aggregated distribution patterns among large- than small-bodied invertebrates. The species-specific interactions seem sufficiently...

  15. Size Evolution and Stochastic Models: Explaining Ostracod Size through Probabilistic Distributions

    Science.gov (United States)

    Krawczyk, M.; Decker, S.; Heim, N. A.; Payne, J.

    2014-12-01

    The biovolume of animals has functioned as an important benchmark for measuring evolution throughout geologic time. In our project, we examined the observed average body size of ostracods over time in order to understand the mechanism of size evolution in these marine organisms. The body size of ostracods has varied since the beginning of the Ordovician, where the first true ostracods appeared. We created a stochastic branching model to create possible evolutionary trees of ostracod size. Using stratigraphic ranges for ostracods compiled from over 750 genera in the Treatise on Invertebrate Paleontology, we calculated overall speciation and extinction rates for our model. At each timestep in our model, new lineages can evolve or existing lineages can become extinct. Newly evolved lineages are assigned sizes based on their parent genera. We parameterized our model to generate neutral and directional changes in ostracod size to compare with the observed data. New sizes were chosen via a normal distribution, and the neutral model selected new sizes differentials centered on zero, allowing for an equal chance of larger or smaller ostracods at each speciation. Conversely, the directional model centered the distribution on a negative value, giving a larger chance of smaller ostracods. Our data strongly suggests that the overall direction of ostracod evolution has been following a model that directionally pushes mean ostracod size down, shying away from a neutral model. Our model was able to match the magnitude of size decrease. Our models had a constant linear decrease while the actual data had a much more rapid initial rate followed by a constant size. The nuance of the observed trends ultimately suggests a more complex method of size evolution. In conclusion, probabilistic methods can provide valuable insight into possible evolutionary mechanisms determining size evolution in ostracods.

  16. Trait modality distribution of aquatic macrofauna communities as explained by pesticides and water chemistry.

    Science.gov (United States)

    Ieromina, O; Musters, C J M; Bodegom, P M; Peijnenburg, W J G M; Vijver, M G

    2016-08-01

    Analyzing functional species' characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2-4 % to pesticides, and for 3-11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches.

  17. Spatial distribution patterns of the peppery furrow shell Scrobicularia plana (da Costa, 1778) along the European coast: A review

    Science.gov (United States)

    Santos, Sílvia; Luttikhuizen, Pieternella C.; Campos, Joana; Heip, Carlo H. R.; van der Veer, Henk W.

    2011-10-01

    The bivalve Scrobicularia plana is an important species of shallow water benthic communities with a wide geographic distribution but also with a general patchy pattern, i.e. irregular in occurrence and in density. This review aims to determine the processes responsible for the species' spatial distribution pattern based on the available information on S. plana. Although several pre- and post-settlement processes are believed to influence spatial patterns of marine invertebrates, the general patchy distribution of S. plana seems to be determined by the existence of specific environmental conditions during settlement. Factors such as temperature, salinity, sediment type, hydrographic conditions and predation affect settlement and spat survival and not one but a combination of factors seems to explain the species distribution pattern. Future work should focus on determining the scale of patchiness, using hierarchical sampling, as well as the connectivity between populations by analysing the population genetic structure.

  18. Can Sulfur Explain the Bimodal Color Distribution Observed in the Jupiter Trojans?

    Science.gov (United States)

    Blacksberg, Jordana; Mahjoub, Ahmed; Poston, Michael; Brown, Michael E.; Eiler, John; Ehlmann, Bethany; Hodyss, Robert; Hand, Kevin P.; Carlson, Robert W.; Wong, Ian

    2016-10-01

    We present a series of experiments aimed at exploring the hypothesis that the presence or absence of H2S ice on the surface of primitive icy bodies in the early solar system is responsible for the bimodal color distribution of the Jupiter Trojans.Central to our proposed hypothesis is a location-dependent sublimation of ices in the primordial trans-neptunian disk which would have divided objects according to whether they retained H2S on their surfaces for sufficient time to incorporate their constituents into irradiated organic crusts. The irradiated crusts of objects with and without H2S would have different chemistry and therefore different optical properties. Dynamical instability models of the early solar system (e.g. Morbidelli et al., 2005, Nesvorny et al., 2013) predict that Trojans, formed from this primordial population, were later emplaced inward to co-orbit with Jupiter during large-scale rearrangement events. According to our hypothesis, the Trojans today would show evidence of their primordial location with respect to the H2S sublimation line in the form of a bimodal distribution in surface chemistry, and thus color.We present laboratory spectroscopy experiments in support of this hypothesis. Numerous thin ice films composed of H2O, CH3OH, NH3, were produced both with and without H2S. Subsequent processing of these icy bodies was simulated using electron irradiation and heating. Visible reflectance spectra show significant reddening when H2S is present. Mid-infrared spectra confirm the formation of non-volatile sulfur-containing molecules in the products of H2S-containing ices. The infrared spectral properties of the organic residues remaining at room temperature show that sulfur significantly changes the chemistry of these irradiation-produced organics. These experiments suggest that the presence of specific sulfur-bearing chemical species may play an important role in the colors of both the KBOs and Trojans today. This testable hypothesis could feed

  19. Human leptospirosis distribution pattern analysis in Hulu Langat, Selangor

    Science.gov (United States)

    Zulkifli, Zuhafiza; Shariff, Abdul Rashid Mohamed; Tarmidi, Zakri M.

    2016-06-01

    This paper discussed the distribution pattern of human leptospirosis in the Hulu Langat District, Selangor, Malaysia. The data used in this study is leptospirosis cases’ report, and spatial boundaries. Leptospirosis cases, data were collected from Health Office of Hulu Langat and spatial boundaries, including lot and district boundaries was collected from the Department of Mapping and Surveying Malaysia (JUPEM). A total of 599 leptospirosis cases were reported in 2013, and this data was mapped based on the addresses provided in the leptospirosis cases’ report. This study uses three statistical methods to analyze the distribution pattern; Moran's I, average nearest neighborhood (ANN) and kernel density estimation. The analysis was used to determine the spatial distribution and the average distance of leptospirosis cases and located the hotspot locations. Using Moran's I analysis, results indicated the cases were random, with a value of -0.202816 which show negative spatial autocorrelation exist among leptospirosis cases. The ANN analysis result, indicated the cases are in cluster pattern, with value of the average nearest neighbor ratio is -21.80. And results also show the hotspots are has been identified and mapped in the Hulu Langat District.

  20. Active Degradation Explains the Distribution of Nuclear Proteins during Cellular Senescence.

    Directory of Open Access Journals (Sweden)

    Enrico Giampieri

    Full Text Available The amount of cellular proteins is a crucial parameter that is known to vary between cells as a function of the replicative passages, and can be important during physiological aging. The process of protein degradation is known to be performed by a series of enzymatic reactions, ranging from an initial step of protein ubiquitination to their final fragmentation by the proteasome. In this paper we propose a stochastic dynamical model of nuclear proteins concentration resulting from a balance between a constant production of proteins and their degradation by a cooperative enzymatic reaction. The predictions of this model are compared with experimental data obtained by fluorescence measurements of the amount of nuclear proteins in murine tail fibroblast (MTF undergoing cellular senescence. Our model provides a three-parameter stationary distribution that is in good agreement with the experimental data even during the transition to the senescent state, where the nuclear protein concentration changes abruptly. The estimation of three parameters (cooperativity, saturation threshold, and maximal velocity of the reaction, and their evolution during replicative passages shows that only the maximal velocity varies significantly. Based on our modeling we speculate the reduction of functionality of the protein degradation mechanism as a possible competitive inhibition of the proteasome.

  1. Decoding Size Distribution Patterns in Marine and Transitional Water Phytoplankton: From Community to Species Level

    Science.gov (United States)

    Roselli, Leonilde; Basset, Alberto

    2015-01-01

    Understanding the mechanisms of phytoplankton community assembly is a fundamental issue of aquatic ecology. Here, we use field data from transitional (e.g. coastal lagoons) and coastal water environments to decode patterns of phytoplankton size distribution into organization and adaptive mechanisms. Transitional waters are characterized by higher resource availability and shallower well-mixed water column than coastal marine environments. Differences in physico-chemical regime between the two environments have been hypothesized to exert contrasting selective pressures on phytoplankton cell morphology (size and shape). We tested the hypothesis focusing on resource availability (nutrients and light) and mixed layer depth as ecological axes that define ecological niches of phytoplankton. We report fundamental differences in size distributions of marine and freshwater diatoms, with transitional water phytoplankton significantly smaller and with higher surface to volume ratio than marine species. Here, we hypothesize that mixing condition affecting size-dependent sinking may drive phytoplankton size and shape distributions. The interplay between shallow mixed layer depth and frequent and complete mixing of transitional waters may likely increase the competitive advantage of small phytoplankton limiting large cell fitness. The nutrient regime appears to explain the size distribution within both marine and transitional water environments, while it seem does not explain the pattern observed across the two environments. In addition, difference in light availability across the two environments appear do not explain the occurrence of asymmetric size distribution at each hierarchical level. We hypothesize that such competitive equilibria and adaptive strategies in resource exploitation may drive by organism’s behavior which exploring patch resources in transitional and marine phytoplankton communities. PMID:25974052

  2. Using the satellite-derived normalized difference vegetation index (NDVI) to explain ranging patterns in a lek-breeding antelope: the importance of scale.

    Science.gov (United States)

    Bro-Jørgensen, Jakob; Brown, Molly E; Pettorelli, Nathalie

    2008-11-01

    Lek-breeding species are characterized by a negative association between territorial resource availability and male mating success; however, the impact of resources on the overall distribution patterns of the two sexes in lek systems is not clear. The normalized difference vegetation index (NDVI) has recently emerged as a powerful proxy measure for primary productivity, allowing the links between the distributions of animals and resources to be explored. Using NDVI at four spatial resolutions, we here investigate how the distribution of the two sexes in a lek-breeding population of topi antelopes relates to resource abundance before and during the rut. We found that in the dry season preceding the rut, topi density correlated positively with NDVI at the large, but not the fine, scale. This suggests that before the rut, when resources were relatively scant, topi preferred pastures where green grass was widely abundant. The pattern was less pronounced in males, suggesting that the need for territorial attendance prevents males from tracking resources as freely as females do. During the rut, which occurs in the wet season, both male and female densities correlated negatively with NDVI at the fine scale. At this time, resources were generally plentiful and the results suggest that, rather than by resource maximization, distribution during the rut was determined by benefits of aggregating on relatively resource-poor leks for mating, and possibly antipredator, purposes. At the large scale, no correlation between density and NDVI was found during the rut in either sex, which can be explained by leks covering areas too small to be reflected at this resolution. The study illustrates that when investigating spatial organization, it is important: (1) to choose the appropriate analytic scale, and (2) to consider behavioural as well as strictly ecological factors.

  3. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

    Energy Technology Data Exchange (ETDEWEB)

    Straczek, Anne; Duquene, Lise [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Wegrzynek, Dariusz [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Chinea-Cano, Ernesto [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Wannijn, Jean [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Navez, Jacques [Royal Museum of Africa, Department of Geology, Leuvensesteenweg 13, 3080 Tervuren (Belgium); Vandenhove, Hildegarde, E-mail: hvandenh@sckcen.b [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium)

    2010-03-15

    Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 mumol U L{sup -1}, distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.

  4. Marine biodiversity in the Caribbean: regional estimates and distribution patterns.

    Directory of Open Access Journals (Sweden)

    Patricia Miloslavich

    Full Text Available This paper provides an analysis of the distribution patterns of marine biodiversity and summarizes the major activities of the Census of Marine Life program in the Caribbean region. The coastal Caribbean region is a large marine ecosystem (LME characterized by coral reefs, mangroves, and seagrasses, but including other environments, such as sandy beaches and rocky shores. These tropical ecosystems incorporate a high diversity of associated flora and fauna, and the nations that border the Caribbean collectively encompass a major global marine biodiversity hot spot. We analyze the state of knowledge of marine biodiversity based on the geographic distribution of georeferenced species records and regional taxonomic lists. A total of 12,046 marine species are reported in this paper for the Caribbean region. These include representatives from 31 animal phyla, two plant phyla, one group of Chromista, and three groups of Protoctista. Sampling effort has been greatest in shallow, nearshore waters, where there is relatively good coverage of species records; offshore and deep environments have been less studied. Additionally, we found that the currently accepted classification of marine ecoregions of the Caribbean did not apply for the benthic distributions of five relatively well known taxonomic groups. Coastal species richness tends to concentrate along the Antillean arc (Cuba to the southernmost Antilles and the northern coast of South America (Venezuela-Colombia, while no pattern can be observed in the deep sea with the available data. Several factors make it impossible to determine the extent to which these distribution patterns accurately reflect the true situation for marine biodiversity in general: (1 highly localized concentrations of collecting effort and a lack of collecting in many areas and ecosystems, (2 high variability among collecting methods, (3 limited taxonomic expertise for many groups, and (4 differing levels of activity in the study

  5. Marine Biodiversity in the Caribbean: Regional Estimates and Distribution Patterns

    Science.gov (United States)

    Miloslavich, Patricia; Díaz, Juan Manuel; Klein, Eduardo; Alvarado, Juan José; Díaz, Cristina; Gobin, Judith; Escobar-Briones, Elva; Cruz-Motta, Juan José; Weil, Ernesto; Cortés, Jorge; Bastidas, Ana Carolina; Robertson, Ross; Zapata, Fernando; Martín, Alberto; Castillo, Julio; Kazandjian, Aniuska; Ortiz, Manuel

    2010-01-01

    This paper provides an analysis of the distribution patterns of marine biodiversity and summarizes the major activities of the Census of Marine Life program in the Caribbean region. The coastal Caribbean region is a large marine ecosystem (LME) characterized by coral reefs, mangroves, and seagrasses, but including other environments, such as sandy beaches and rocky shores. These tropical ecosystems incorporate a high diversity of associated flora and fauna, and the nations that border the Caribbean collectively encompass a major global marine biodiversity hot spot. We analyze the state of knowledge of marine biodiversity based on the geographic distribution of georeferenced species records and regional taxonomic lists. A total of 12,046 marine species are reported in this paper for the Caribbean region. These include representatives from 31 animal phyla, two plant phyla, one group of Chromista, and three groups of Protoctista. Sampling effort has been greatest in shallow, nearshore waters, where there is relatively good coverage of species records; offshore and deep environments have been less studied. Additionally, we found that the currently accepted classification of marine ecoregions of the Caribbean did not apply for the benthic distributions of five relatively well known taxonomic groups. Coastal species richness tends to concentrate along the Antillean arc (Cuba to the southernmost Antilles) and the northern coast of South America (Venezuela – Colombia), while no pattern can be observed in the deep sea with the available data. Several factors make it impossible to determine the extent to which these distribution patterns accurately reflect the true situation for marine biodiversity in general: (1) highly localized concentrations of collecting effort and a lack of collecting in many areas and ecosystems, (2) high variability among collecting methods, (3) limited taxonomic expertise for many groups, and (4) differing levels of activity in the study of

  6. Marine biodiversity in the Caribbean: regional estimates and distribution patterns.

    Science.gov (United States)

    Miloslavich, Patricia; Díaz, Juan Manuel; Klein, Eduardo; Alvarado, Juan José; Díaz, Cristina; Gobin, Judith; Escobar-Briones, Elva; Cruz-Motta, Juan José; Weil, Ernesto; Cortés, Jorge; Bastidas, Ana Carolina; Robertson, Ross; Zapata, Fernando; Martín, Alberto; Castillo, Julio; Kazandjian, Aniuska; Ortiz, Manuel

    2010-08-02

    This paper provides an analysis of the distribution patterns of marine biodiversity and summarizes the major activities of the Census of Marine Life program in the Caribbean region. The coastal Caribbean region is a large marine ecosystem (LME) characterized by coral reefs, mangroves, and seagrasses, but including other environments, such as sandy beaches and rocky shores. These tropical ecosystems incorporate a high diversity of associated flora and fauna, and the nations that border the Caribbean collectively encompass a major global marine biodiversity hot spot. We analyze the state of knowledge of marine biodiversity based on the geographic distribution of georeferenced species records and regional taxonomic lists. A total of 12,046 marine species are reported in this paper for the Caribbean region. These include representatives from 31 animal phyla, two plant phyla, one group of Chromista, and three groups of Protoctista. Sampling effort has been greatest in shallow, nearshore waters, where there is relatively good coverage of species records; offshore and deep environments have been less studied. Additionally, we found that the currently accepted classification of marine ecoregions of the Caribbean did not apply for the benthic distributions of five relatively well known taxonomic groups. Coastal species richness tends to concentrate along the Antillean arc (Cuba to the southernmost Antilles) and the northern coast of South America (Venezuela-Colombia), while no pattern can be observed in the deep sea with the available data. Several factors make it impossible to determine the extent to which these distribution patterns accurately reflect the true situation for marine biodiversity in general: (1) highly localized concentrations of collecting effort and a lack of collecting in many areas and ecosystems, (2) high variability among collecting methods, (3) limited taxonomic expertise for many groups, and (4) differing levels of activity in the study of different

  7. Mountain uplift explains differences in Palaeogene patterns of mammalian evolution and extinction between North America and Europe.

    Science.gov (United States)

    Eronen, Jussi T; Janis, Christine M; Chamberlain, C Page; Mulch, Andreas

    2015-06-22

    Patterns of late Palaeogene mammalian evolution appear to be very different between Eurasia and North America. Around the Eocene-Oligocene (EO) transition global temperatures in the Northern Hemisphere plummet: following this, European mammal faunas undergo a profound extinction event (the Grande Coupure), while in North America they appear to pass through this temperature event unscathed. Here, we investigate the role of surface uplift to environmental change and mammalian evolution through the Palaeogene (66-23 Ma). Palaeogene regional surface uplift in North America caused large-scale reorganization of precipitation patterns, particularly in the continental interior, in accord with our combined stable isotope and ecometric data. Changes in mammalian faunas reflect that these were dry and high-elevation palaeoenvironments. The scenario of Middle to Late Eocene (50-37 Ma) surface uplift, together with decreasing precipitation in higher-altitude regions of western North America, explains the enigma of the apparent lack of the large-scale mammal faunal change around the EO transition that characterized western Europe. We suggest that North American mammalian faunas were already pre-adapted to cooler and drier conditions preceding the EO boundary, resulting from the effects of a protracted history of surface uplift. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. Seasonality in cholera dynamics: A rainfall-driven model explains the wide range of patterns in endemic areas

    Science.gov (United States)

    Baracchini, Theo; King, Aaron A.; Bouma, Menno J.; Rodó, Xavier; Bertuzzo, Enrico; Pascual, Mercedes

    2017-10-01

    Seasonal patterns in cholera dynamics exhibit pronounced variability across geographical regions, showing single or multiple peaks at different times of the year. Although multiple hypotheses related to local climate variables have been proposed, an understanding of this seasonal variation remains incomplete. The historical Bengal region, which encompasses the full range of cholera's seasonality observed worldwide, provides a unique opportunity to gain insights on underlying environmental drivers. Here, we propose a mechanistic, rainfall-temperature driven, stochastic epidemiological model which explicitly accounts for the fluctuations of the aquatic reservoir, and analyze with this model the historical dataset of cholera mortality in the Bengal region. Parameters are inferred with a recently developed sequential Monte Carlo method for likelihood maximization in partially observed Markov processes. Results indicate that the hydrological regime is a major driver of the seasonal dynamics of cholera. Rainfall tends to buffer the propagation of the disease in wet regions due to the longer residence times of water in the environment and an associated dilution effect, whereas it enhances cholera resurgence in dry regions. Moreover, the dynamics of the environmental water reservoir determine whether the seasonality is unimodal or bimodal, as well as its phase relative to the monsoon. Thus, the full range of seasonal patterns can be explained based solely on the local variation of rainfall and temperature. Given the close connection between cholera seasonality and environmental conditions, a deeper understanding of the underlying mechanisms would allow the better management and planning of public health policies with respect to climate variability and climate change.

  9. Experience matters: context-dependent decisions explain spatial foraging patterns in the deposit-feeding crab Scopimera intermedia.

    Science.gov (United States)

    Hui, T Y; Williams, Gray A

    2017-08-30

    Behavioural decisions are often context-dependent, where information from immediate experience is incorporated into an individual's decision-making, particularly in complex environments. To test whether such mechanism is adopted by foragers in heterogeneous environments, we investigated the foraging behaviour of the deposit-feeding sand-bubbler crab, Scopimera intermedia An individual-based model was constructed, based on an optimal-patch selection criterion, which implicitly assumed that individuals adjust foraging decisions based on immediate past experience. The model's predictions were tested on the shore by manipulating the location of food patches, where the crab showed a strong context-dependent foraging pattern. When resources were randomly distributed, the crab responded by spending 56% of time in enriched patches compared with only 28% in the same area when patches were composed of natural sediments. Shore manipulations varying resource distribution supported the underlying principles of the model mechanism, and highlighted the benefits of such a strategy in heterogeneous environments such as intertidal sediments where food resources vary at different spatial and temporal scales. The proposed model therefore provides a mechanistic process, based on optimal foraging, to predict foraging decisions and movement patterns of animals feeding in heterogeneous landscapes. © 2017 The Author(s).

  10. Distributional patterns and possible origin of leafhoppers (Homoptera, Cicadellidae

    Directory of Open Access Journals (Sweden)

    Mervin W. Nielson

    2000-03-01

    . Vicariance (physical was the principal event that appealed to explain the distribution of many subfamilies and tribes whereas dispersal accounted for distribution of the majority of interzoogeographical genera.

  11. Towards Scalable Distributed Framework for Urban Congestion Traffic Patterns Warehousing

    Directory of Open Access Journals (Sweden)

    A. Boulmakoul

    2015-01-01

    Full Text Available We put forward architecture of a framework for integration of data from moving objects related to urban transportation network. Most of this research refers to the GPS outdoor geolocation technology and uses distributed cloud infrastructure with big data NoSQL database. A network of intelligent mobile sensors, distributed on urban network, produces congestion traffic patterns. Congestion predictions are based on extended simulation model. This model provides traffic indicators calculations, which fuse with the GPS data for allowing estimation of traffic states across the whole network. The discovery process of congestion patterns uses semantic trajectories metamodel given in our previous works. The challenge of the proposed solution is to store patterns of traffic, which aims to ensure the surveillance and intelligent real-time control network to reduce congestion and avoid its consequences. The fusion of real-time data from GPS-enabled smartphones integrated with those provided by existing traffic systems improves traffic congestion knowledge, as well as generating new information for a soft operational control and providing intelligent added value for transportation systems deployment.

  12. Explaining local-scale species distributions: relative contributions of spatial autocorrelation and landscape heterogeneity for an avian assemblage.

    Science.gov (United States)

    Mattsson, Brady J; Zipkin, Elise F; Gardner, Beth; Blank, Peter J; Sauer, John R; Royle, J Andrew

    2013-01-01

    Understanding interactions between mobile species distributions and landcover characteristics remains an outstanding challenge in ecology. Multiple factors could explain species distributions including endogenous evolutionary traits leading to conspecific clustering and endogenous habitat features that support life history requirements. Birds are a useful taxon for examining hypotheses about the relative importance of these factors among species in a community. We developed a hierarchical Bayes approach to model the relationships between bird species occupancy and local landcover variables accounting for spatial autocorrelation, species similarities, and partial observability. We fit alternative occupancy models to detections of 90 bird species observed during repeat visits to 316 point-counts forming a 400-m grid throughout the Patuxent Wildlife Research Refuge in Maryland, USA. Models with landcover variables performed significantly better than our autologistic and null models, supporting the hypothesis that local landcover heterogeneity is important as an exogenous driver for species distributions. Conspecific clustering alone was a comparatively poor descriptor of local community composition, but there was evidence for spatial autocorrelation in all species. Considerable uncertainty remains whether landcover combined with spatial autocorrelation is most parsimonious for describing bird species distributions at a local scale. Spatial structuring may be weaker at intermediate scales within which dispersal is less frequent, information flows are localized, and landcover types become spatially diversified and therefore exhibit little aggregation. Examining such hypotheses across species assemblages contributes to our understanding of community-level associations with conspecifics and landscape composition.

  13. Explaining local-scale species distributions: relative contributions of spatial autocorrelation and landscape heterogeneity for an avian assemblage.

    Directory of Open Access Journals (Sweden)

    Brady J Mattsson

    Full Text Available Understanding interactions between mobile species distributions and landcover characteristics remains an outstanding challenge in ecology. Multiple factors could explain species distributions including endogenous evolutionary traits leading to conspecific clustering and endogenous habitat features that support life history requirements. Birds are a useful taxon for examining hypotheses about the relative importance of these factors among species in a community. We developed a hierarchical Bayes approach to model the relationships between bird species occupancy and local landcover variables accounting for spatial autocorrelation, species similarities, and partial observability. We fit alternative occupancy models to detections of 90 bird species observed during repeat visits to 316 point-counts forming a 400-m grid throughout the Patuxent Wildlife Research Refuge in Maryland, USA. Models with landcover variables performed significantly better than our autologistic and null models, supporting the hypothesis that local landcover heterogeneity is important as an exogenous driver for species distributions. Conspecific clustering alone was a comparatively poor descriptor of local community composition, but there was evidence for spatial autocorrelation in all species. Considerable uncertainty remains whether landcover combined with spatial autocorrelation is most parsimonious for describing bird species distributions at a local scale. Spatial structuring may be weaker at intermediate scales within which dispersal is less frequent, information flows are localized, and landcover types become spatially diversified and therefore exhibit little aggregation. Examining such hypotheses across species assemblages contributes to our understanding of community-level associations with conspecifics and landscape composition.

  14. Global distribution of a key trophic guild contrasts with common latitudinal diversity patterns.

    Science.gov (United States)

    Boyero, Luz; Pearson, Richard G; Dudgeon, David; Graça, Manuel A S; Gessner, Mark O; Albariño, Ricardo J; Ferreira, Verónica; Yule, Catherine M; Boulton, Andrew J; Arunachalam, Muthukumarasamy; Callisto, Marcos; Chauvet, Eric; Ramírez, Alonso; Chará, Julián; Moretti, Marcelo S; Gonçalves, José F; Helson, Julie E; Chará-Serna, Ana M; Encalada, Andrea C; Davies, Judy N; Lamothe, Sylvain; Cornejo, Aydeè; Li, Aggie O Y; Buria, Leonardo M; Villanueva, Verónica D; Zúñiga, María C; Pringle, Catherine M

    2011-09-01

    Most hypotheses explaining the general gradient of higher diversity toward the equator are implicit or explicit about greater species packing in the tropics. However, global patterns of diversity within guilds, including trophic guilds (i.e., groups of organisms that use similar food resources), are poorly known. We explored global diversity patterns of a key trophic guild in stream ecosystems, the detritivore shredders. This was motivated by the fundamental ecological role of shredders as decomposers of leaf litter and by some records pointing to low shredder diversity and abundance in the tropics, which contrasts with diversity patterns of most major taxa for which broad-scale latitudinal patterns haven been examined. Given this evidence, we hypothesized that shredders are more abundant and diverse in temperate than in tropical streams, and that this pattern is related to the higher temperatures and lower availability of high-quality leaf litter in the tropics. Our comprehensive global survey (129 stream sites from 14 regions on six continents) corroborated the expected latitudinal pattern and showed that shredder distribution (abundance, diversity and assemblage composition) was explained by a combination of factors, including water temperature (some taxa were restricted to cool waters) and biogeography (some taxa were more diverse in particular biogeographic realms). In contrast to our hypothesis, shredder diversity was unrelated to leaf toughness, but it was inversely related to litter diversity. Our findings markedly contrast with global trends of diversity for most taxa, and with the general rule of higher consumer diversity at higher levels of resource diversity. Moreover, they highlight the emerging role of temperature in understanding global patterns of diversity, which is of great relevance in the face of projected global warming.

  15. Storm blueprints patterns for distributed real-time computation

    CERN Document Server

    Goetz, P Taylor

    2014-01-01

    A blueprints book with 10 different projects built in 10 different chapters which demonstrate the various use cases of storm for both beginner and intermediate users, grounded in real-world example applications.Although the book focuses primarily on Java development with Storm, the patterns are more broadly applicable and the tips, techniques, and approaches described in the book apply to architects, developers, and operations.Additionally, the book should provoke and inspire applications of distributed computing to other industries and domains. Hadoop enthusiasts will also find this book a go

  16. Probability Measure of Navigation pattern predition using Poisson Distribution Analysis

    OpenAIRE

    Dr.V.Valli Mayil; Ms. R. Rooba; Ms. C. Parimala

    2012-01-01

    The World Wide Web has become one of the most important media to store, share and distribute information. The rapid expansion of the web has provided a great opportunity to study user and system behavior by exploring web access logs. Web Usage Mining is the application of data mining techniques to large web data repositories in order to extract usage patterns. Every web server keeps a log of all transactions between the server and the clients. The log data which are collected by web servers c...

  17. Large scale patterns in vertical distribution and behaviour of mesopelagic scattering layers

    KAUST Repository

    Klevjer, Thor Aleksander

    2016-01-27

    Recent studies suggest that previous estimates of mesopelagic biomasses are severely biased, with the new, higher estimates underlining the need to unveil behaviourally mediated coupling between shallow and deep ocean habitats. We analysed vertical distribution and diel vertical migration (DVM) of mesopelagic acoustic scattering layers (SLs) recorded at 38 kHz across oceanographic regimes encountered during the circumglobal Malaspina expedition. Mesopelagic SLs were observed in all areas covered, but vertical distributions and DVM patterns varied markedly. The distribution of mesopelagic backscatter was deepest in the southern Indian Ocean (weighted mean daytime depth: WMD 590 m) and shallowest at the oxygen minimum zone in the eastern Pacific (WMD 350 m). DVM was evident in all areas covered, on average ~50% of mesopelagic backscatter made daily excursions from mesopelagic depths to shallow waters. There were marked differences in migrating proportions between the regions, ranging from ~20% in the Indian Ocean to ~90% in the Eastern Pacific. Overall the data suggest strong spatial gradients in mesopelagic DVM patterns, with implied ecological and biogeochemical consequences. Our results suggest that parts of this spatial variability can be explained by horizontal patterns in physical-chemical properties of water masses, such as oxygen, temperature and turbidity.

  18. Daily pattern of energy distribution and weight loss.

    Science.gov (United States)

    Raynor, Hollie A; Li, Fan; Cardoso, Chelsi

    2018-02-19

    Timing of energy intake, a temporal dietary pattern, may enhance health. Eating a greater amount of energy earlier and a smaller amount of energy later in the day, a behavioral circadian rhythm, may assist with chronoenhancement. Chronoenhancement seeks to enhance entrainment (synchronization) of biological and behavioral circadian rhythms. In humans, research reports that eating a greater amount of energy early and a smaller amount of energy later in the day increases dietary induced thermogenesis, improves cardiometabolic outcomes, and enhances weight loss. However, little human research has examined if this eating pattern enhances regularity of biological circadian rhythm. In a randomized controlled 8-week pilot study, the influence of energy distribution timing on weight loss and regularity of sleep onset and wake times (marker for biological circadian rhythm) was examined. Within an hypocaloric, three-meal prescription, participants (n = 8) were assigned to either: 1) Morning: 50%, 30%, and 20% of kcal at breakfast, lunch, and dinner, respectively; or 2) Evening: 20%, 30%, and 50% of kcal at breakfast, lunch, and dinner, respectively. Percent weight loss and regularity of sleep onset and wake times were significantly (p energy distribution timing on health, longer studies conducted in free-living participants, with dietary intake assessed using time-stamped methods, that include measures of the circadian timing system are needed. This small review is based upon a symposium presentation at the Society of the Study of Ingestive Behavior in 2017. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Community context and sub-neighborhood scale detail to explain dengue, chikungunya and Zika patterns in Cali, Colombia.

    Directory of Open Access Journals (Sweden)

    Amy R Krystosik

    Full Text Available Cali, Colombia has experienced chikungunya and Zika outbreaks and hypoendemic dengue. Studies have explained Cali's dengue patterns but lack the sub-neighborhood-scale detail investigated here.Spatial-video geonarratives (SVG with Ministry of Health officials and Community Health Workers were collected in hotspots, providing perspective on perceptions of why dengue, chikungunya and Zika hotspots exist, impediments to control, and social outcomes. Using spatial video and Google Street View, sub-neighborhood features possibly contributing to incidence were mapped to create risk surfaces, later compared with dengue, chikungunya and Zika case data.SVG captured insights in 24 neighborhoods. Trash and water risks in Calipso were mapped using SVG results. Perceived risk factors included proximity to standing water, canals, poverty, invasions, localized violence and military migration. These risks overlapped case density maps and identified areas that are suitable for transmission but are possibly underreporting to the surveillance system.Resulting risk maps with local context could be leveraged to increase vector-control efficiency- targeting key areas of environmental risk.

  20. Community context and sub-neighborhood scale detail to explain dengue, chikungunya and Zika patterns in Cali, Colombia.

    Science.gov (United States)

    Krystosik, Amy R; Curtis, Andrew; Buritica, Paola; Ajayakumar, Jayakrishnan; Squires, Robert; Dávalos, Diana; Pacheco, Robinson; Bhatta, Madhav P; James, Mark A

    2017-01-01

    Cali, Colombia has experienced chikungunya and Zika outbreaks and hypoendemic dengue. Studies have explained Cali's dengue patterns but lack the sub-neighborhood-scale detail investigated here. Spatial-video geonarratives (SVG) with Ministry of Health officials and Community Health Workers were collected in hotspots, providing perspective on perceptions of why dengue, chikungunya and Zika hotspots exist, impediments to control, and social outcomes. Using spatial video and Google Street View, sub-neighborhood features possibly contributing to incidence were mapped to create risk surfaces, later compared with dengue, chikungunya and Zika case data. SVG captured insights in 24 neighborhoods. Trash and water risks in Calipso were mapped using SVG results. Perceived risk factors included proximity to standing water, canals, poverty, invasions, localized violence and military migration. These risks overlapped case density maps and identified areas that are suitable for transmission but are possibly underreporting to the surveillance system. Resulting risk maps with local context could be leveraged to increase vector-control efficiency- targeting key areas of environmental risk.

  1. Enhancement of force patterns classification based on Gaussian distributions.

    Science.gov (United States)

    Ertelt, Thomas; Solomonovs, Ilja; Gronwald, Thomas

    2018-01-23

    Description of the patterns of ground reaction force is a standard method in areas such as medicine, biomechanics and robotics. The fundamental parameter is the time course of the force, which is classified visually in particular in the field of clinical diagnostics. Here, the knowledge and experience of the diagnostician is relevant for its assessment. For an objective and valid discrimination of the ground reaction force pattern, a generic method, especially in the medical field, is absolutely necessary to describe the qualities of the time-course. The aim of the presented method was to combine the approaches of two existing procedures from the fields of machine learning and the Gauss approximation in order to take advantages of both methods for the classification of ground reaction force patterns. The current limitations of both methods could be eliminated by an overarching method. Twenty-nine male athletes from different sports were examined. Each participant was given the task of performing a one-legged stopping maneuver on a force plate from the maximum possible starting speed. The individual time course of the ground reaction force of each subject was registered and approximated on the basis of eight Gaussian distributions. The descriptive coefficients were then classified using Bayesian regulated neural networks. The different sports served as the distinguishing feature. Although the athletes were all given the same task, all sports referred to a different quality in the time course of ground reaction force. Meanwhile within each sport, the athletes were homogeneous. With an overall prediction (R = 0.938) all subjects/sports were classified correctly with 94.29% accuracy. The combination of the two methods: the mathematical description of the time course of ground reaction forces on the basis of Gaussian distributions and their classification by means of Bayesian regulated neural networks, seems an adequate and promising method to discriminate the

  2. The population distribution pattern in Xinjiang autonomous region.

    Science.gov (United States)

    Yuan, X

    1994-01-01

    Population distribution in Xinjiang Autonomous Region in China follows a high-density horseshoe-shaped pattern of oases surrounded by mountains and desert comprising 70% of the territory. The Region has the largest geographic area of all provinces, has 15.8 million people, and a population density of 9.5/sq. km. 90% of the total population lives in the more than 500 oases, with a population density of 200 people/sq. km. About 80% of the population has lived in the northwestern part of the province over the past 40 years; density is 15.5 people/sq. km compared to only 3.2 people/sq. km in the southeast. Population concentration is affected by natural resource distribution (water), industrial and agricultural production, transportation, and immigration. Population density increased by 4.7 times in northern Xinjiang, 1.2 times in the south, and 2.9 times in the east. Population concentration is also affected by elevation patterns. The largest population (46.33%) is situated in areas 1000-1500 meters above sea level, with declines at either increased or decreased elevations. Population density declines as elevation increases. Most of the old oases were situated in basins between 500 and 1000 meters in the north and between 1000 and 1500 meters in the south. Areas below 500 meters in the north and areas below 100 meters in the south are desert. Population distribution varied among the southern slope of the Altay Mountains, the northern slope of the Tianshan Mountains between 100 and 2500 meters, the eastern part of the northern slope of the Tianshan Mountains, the southern slope of the Tianshan Mountains, the western part of the southern slope of the Tianshan Mountains, the northern slope of the Kunlun Mountains, in Pamirs and the eastern slope of the Tianshan Mountains, and old oases at 500-1000 meters in the heart of Xinjiang, where major transportation routes cross China.

  3. Triadic closure dynamics explains scaling-exponents for preferential attachment-, degree- and clustering distributions in social multiplex data

    CERN Document Server

    Klimek, Peter

    2013-01-01

    Social networks exhibit scaling-laws for several structural characteristics, such as the degree distribution, the scaling of the attachment kernel, and the clustering coefficients as a function of node degree. A detailed understanding if and how these scaling laws are inter-related is missing so far, let alone whether they can be understood through a common, dynamical principle. We propose a simple model for stationary network formation and show that the three mentioned scaling relations follow as natural consequences of triadic closure. The validity of the model is tested on multiplex data from a well studied massive multiplayer online game. We find that the three scaling exponents observed in the multiplex data for the friendship, communication and trading networks can simultaneously be explained by the model. These results suggest that triadic closure could be identified as one of the fundamental dynamical principles in social multiplex network formation.

  4. Geographic distribution of suitable hosts explains the evolution of specialized gentes in the European cuckoo Cuculus canorus

    Science.gov (United States)

    Soler, Juan J; Vivaldi, Manuel Martín; Møller, Anders Pape

    2009-01-01

    Background Several types of selective forces can act to promote parasite specialization. Parasites might specialize on some suitable hosts at the cost of decreasing effectiveness when exploiting other species of hosts, and specialization can be more easily selected for in hosts that the parasites will easily find. Thus demographic characteristics of suitable hosts such as population density and its spatial consistency could be key factors predicting probability of parasite specialization and speciation. Here, we explore this hypothesis by studying the relationship between occurence of specialized races of the European cuckoo (Cuculus canorus) (i.e. gentes) and mean and coefficient of variation in population density estimated for 12 different European regions. Results The results were in accordance with the hypothesis because specialized cuckoo egg morphs were more common in suitable hosts with high population density and low variation in population density at the level of host species or genera. Conclusion We have presented evidence suggesting that population density and homogeneity of geographic distribution of hosts explain, at least partly, the evolution of specialized egg-morphs of the European cuckoo. These results are consistent with the hypothesis that resource (i.e., host) predictability explains the evolution of host races and species of parasites. PMID:19405966

  5. Geographic distribution of suitable hosts explains the evolution of specialized gentes in the European cuckoo Cuculus canorus

    Directory of Open Access Journals (Sweden)

    Møller Anders

    2009-04-01

    Full Text Available Abstract Background Several types of selective forces can act to promote parasite specialization. Parasites might specialize on some suitable hosts at the cost of decreasing effectiveness when exploiting other species of hosts, and specialization can be more easily selected for in hosts that the parasites will easily find. Thus demographic characteristics of suitable hosts such as population density and its spatial consistency could be key factors predicting probability of parasite specialization and speciation. Here, we explore this hypothesis by studying the relationship between occurence of specialized races of the European cuckoo (Cuculus canorus (i.e. gentes and mean and coefficient of variation in population density estimated for 12 different European regions. Results The results were in accordance with the hypothesis because specialized cuckoo egg morphs were more common in suitable hosts with high population density and low variation in population density at the level of host species or genera. Conclusion We have presented evidence suggesting that population density and homogeneity of geographic distribution of hosts explain, at least partly, the evolution of specialized egg-morphs of the European cuckoo. These results are consistent with the hypothesis that resource (i.e., host predictability explains the evolution of host races and species of parasites.

  6. Agricultural Terrace Pattern Distribution and Preservation along Climatic Gradient

    Science.gov (United States)

    Ackermann, Oren

    2017-04-01

    Agricultural terraces are a well-distributed agrotechnical method for planting in various places in the world, from ancient time and until today. The aim of the current research is to demonstrate the spatial distribution and conservation of agricultural terraces along a climatic gradient of sub-humid Mediterranean, semi-arid and arid climate zones by presenting the case study of the Land of Israel. In the Judean Mountains (central Israel), a region under sub-humid Mediterranean conditions, agricultural terraces are characterized by terrace coverage on slopes and in valleys. Annual rainfall average in this region is 800 mm, allowing for vast rain-fed agriculture based on direct rain. In the Judean Shephelah (central Israel), a region under semi-arid conditions, agriculture terraces are located in small spots on the slopes, and in terrace fields in the valleys. Annual average rainfall in this region is between 300 and 400 mm. Rain-fed agriculture was sustained by direct rain and additional runoff generated on rock outcrops. In the Negev Highlands, (southern Israel), a region under arid climate conditions with annual rainfall average of 100 mm, runoff farm terraces are located in valleys, and agriculture sustenance was based on water harvesting from the slopes. The terraces pattern distribution is similar to the natural vegetation pattern distribution of the three given areas. During the past ten of years, changes in land use and farming methods have resulted in the abandonment of many agricultural terraces in the given areas. Terrace abandonment leads to the collapse of retaining walls and erosion of soil and sediments from the terrace body with the latter occurring at a high rate in the arid Negev highlands. However, in the Judean Mountains and the Judean Shephelah, areas under sub-humid Mediterranean and semi-arid conditions, the intensity of erosion is lower since the terraces are covered by dense shrubs such as Sarcopoterium spinosum or by trees. This plant cover

  7. Quantifying shark distribution patterns and species-habitat associations: implications of marine park zoning.

    Science.gov (United States)

    Espinoza, Mario; Cappo, Mike; Heupel, Michelle R; Tobin, Andrew J; Simpfendorfer, Colin A

    2014-01-01

    Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS) along the entire Great Barrier Reef Marine Park (GBRMP) over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances). Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites) relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation approaches.

  8. Quantifying shark distribution patterns and species-habitat associations: implications of marine park zoning.

    Directory of Open Access Journals (Sweden)

    Mario Espinoza

    Full Text Available Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS along the entire Great Barrier Reef Marine Park (GBRMP over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances. Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation

  9. GEMAS: Molybdenum Spatial Distribution Patterns in European Soil

    Science.gov (United States)

    Cicchella, Domenico; Zuzolo, Daniela; Demetriades, Alecos; De Vivo, Benedetto; Eklund, Mikael; Ladenberger, Anna; Negrel, Philippe; O'Connor, Patrick

    2017-04-01

    Molybdenum is an essential trace element for both plants and animals as well as for human being. It is one such trace element for which potential health concerns have been raised but for which few data exist and little investigation or interpretation of distributions in soils has been made. The main goal of this study was to fill this gap. Molybdenum (Mo) concentrations are reported for the interesting anomalous patterns occur also in Italy in correspondence with alkaline volcanics, in Spain and Greece associated with sulfides mineralizations and in Slovenia and Croatia where are probably related to the long weathering history of karstic residual soils. Anomalous concentrations in some areas of Ireland represent a clear example of how an excess of molybdenum has produced potentially toxic pastures. In fact, these give rise to problems particularly in young cattle when excess molybdenum in the herbage acts as an antagonist, which militates against efficient copper absorption by the animal.

  10. Stepping-stone expansion and habitat loss explain a peculiar genetic structure and distribution of a forest insect.

    Science.gov (United States)

    Cassel-Lundhagen, Anna; Ronnås, Cecilia; Battisti, Andrea; Wallén, Johan; Larsson, Stig

    2013-06-01

    It is challenging to unravel the history of organisms with highly scattered populations. Such species may have fragmented distributions because extant populations are remnants of a previously more continuous range, or because the species has narrow habitat requirements in combination with good dispersal capacity (naturally or vector borne). The northern pine processionary moth Thaumetopoea pinivora has a scattered distribution with fragmented populations in two separate regions, northern and south-western Europe. The aims of this study were to explore the glacial and postglacial history of T. pinivora, and add to the understanding of its current distribution and level of contemporary gene flow. We surveyed published records of its occurrence and analysed individuals from a representative subset of populations across the range. A 633 bp long fragment of the mtDNA COI gene was sequenced and nine polymorphic microsatellite loci were genotyped. Only nine nucleotide sites were polymorphic in the COI gene and 90% of the individuals from across its whole range shared the same haplotype. The microsatellite diversity gradually declined towards the north, and unique alleles were found in only three of the northern and three of southern sites. Genetic structuring did not indicate complete isolation among regions, but an increase of genetic isolation by geographic distance. Approximate Bayesian model choice suggested recent divergence during the postglacial period, but glacial refugia remain unidentified. The progressive reduction of suitable habitats is suggested to explain the genetic structure of the populations and we suggest that T. pinivora is a cold-tolerant relict species, with situation-dependent dispersal. © 2013 John Wiley & Sons Ltd.

  11. Do stacked species distribution models reflect altitudinal diversity patterns?

    Directory of Open Access Journals (Sweden)

    Rubén G Mateo

    Full Text Available The objective of this study was to evaluate the performance of stacked species distribution models in predicting the alpha and gamma species diversity patterns of two important plant clades along elevation in the Andes. We modelled the distribution of the species in the Anthurium genus (53 species and the Bromeliaceae family (89 species using six modelling techniques. We combined all of the predictions for the same species in ensemble models based on two different criteria: the average of the rescaled predictions by all techniques and the average of the best techniques. The rescaled predictions were then reclassified into binary predictions (presence/absence. By stacking either the original predictions or binary predictions for both ensemble procedures, we obtained four different species richness models per taxa. The gamma and alpha diversity per elevation band (500 m was also computed. To evaluate the prediction abilities for the four predictions of species richness and gamma diversity, the models were compared with the real data along an elevation gradient that was independently compiled by specialists. Finally, we also tested whether our richness models performed better than a null model of altitudinal changes of diversity based on the literature. Stacking of the ensemble prediction of the individual species models generated richness models that proved to be well correlated with the observed alpha diversity richness patterns along elevation and with the gamma diversity derived from the literature. Overall, these models tend to overpredict species richness. The use of the ensemble predictions from the species models built with different techniques seems very promising for modelling of species assemblages. Stacking of the binary models reduced the over-prediction, although more research is needed. The randomisation test proved to be a promising method for testing the performance of the stacked models, but other implementations may still be

  12. Do stacked species distribution models reflect altitudinal diversity patterns?

    Science.gov (United States)

    Mateo, Rubén G; Felicísimo, Ángel M; Pottier, Julien; Guisan, Antoine; Muñoz, Jesús

    2012-01-01

    The objective of this study was to evaluate the performance of stacked species distribution models in predicting the alpha and gamma species diversity patterns of two important plant clades along elevation in the Andes. We modelled the distribution of the species in the Anthurium genus (53 species) and the Bromeliaceae family (89 species) using six modelling techniques. We combined all of the predictions for the same species in ensemble models based on two different criteria: the average of the rescaled predictions by all techniques and the average of the best techniques. The rescaled predictions were then reclassified into binary predictions (presence/absence). By stacking either the original predictions or binary predictions for both ensemble procedures, we obtained four different species richness models per taxa. The gamma and alpha diversity per elevation band (500 m) was also computed. To evaluate the prediction abilities for the four predictions of species richness and gamma diversity, the models were compared with the real data along an elevation gradient that was independently compiled by specialists. Finally, we also tested whether our richness models performed better than a null model of altitudinal changes of diversity based on the literature. Stacking of the ensemble prediction of the individual species models generated richness models that proved to be well correlated with the observed alpha diversity richness patterns along elevation and with the gamma diversity derived from the literature. Overall, these models tend to overpredict species richness. The use of the ensemble predictions from the species models built with different techniques seems very promising for modelling of species assemblages. Stacking of the binary models reduced the over-prediction, although more research is needed. The randomisation test proved to be a promising method for testing the performance of the stacked models, but other implementations may still be developed.

  13. Visualization of oxygen distribution patterns caused by coral and algae

    Directory of Open Access Journals (Sweden)

    Andreas F. Haas

    2013-07-01

    Full Text Available Planar optodes were used to visualize oxygen distribution patterns associated with a coral reef associated green algae (Chaetomorpha sp. and a hermatypic coral (Favia sp. separately, as standalone organisms, and placed in close proximity mimicking coral-algal interactions. Oxygen patterns were assessed in light and dark conditions and under varying flow regimes. The images show discrete high oxygen concentration regions above the organisms during lighted periods and low oxygen in the dark. Size and orientation of these areas were dependent on flow regime. For corals and algae in close proximity the 2D optodes show areas of extremely low oxygen concentration at the interaction interfaces under both dark (18.4 ± 7.7 µmol O2 L- 1 and daylight (97.9 ± 27.5 µmol O2 L- 1 conditions. These images present the first two-dimensional visualization of oxygen gradients generated by benthic reef algae and corals under varying flow conditions and provide a 2D depiction of previously observed hypoxic zones at coral algae interfaces. This approach allows for visualization of locally confined, distinctive alterations of oxygen concentrations facilitated by benthic organisms and provides compelling evidence for hypoxic conditions at coral-algae interaction zones.

  14. Spatial and temporal arrival patterns of Madagascar's vertebrate fauna explained by distance, ocean currents, and ancestor type

    Science.gov (United States)

    Samonds, Karen E.; Godfrey, Laurie R.; Ali, Jason R.; Goodman, Steven M.; Vences, Miguel; Sutherland, Michael R.; Irwin, Mitchell T.; Krause, David W.

    2012-01-01

    How, when, and from where Madagascar's vertebrates arrived on the island is poorly known, and a comprehensive explanation for the distribution of its organisms has yet to emerge. We begin to break that impasse by analyzing vertebrate arrival patterns implied by currently existing taxa. For each of 81 clades, we compiled arrival date, source, and ancestor type (obligate freshwater, terrestrial, facultative swimmer, or volant). We analyzed changes in arrival rates, with and without adjusting for clade extinction. Probability of successful transoceanic dispersal is negatively correlated with distance traveled and influenced by ocean currents and ancestor type. Obligate rafters show a decrease in probability of successful transoceanic dispersal from the Paleocene onward, reaching the lowest levels after the mid-Miocene. This finding is consistent with a paleoceanographic model [Ali JR, Huber M (2010) Nature 463:653–656] that predicts Early Cenozoic surface currents periodically conducive to rafting or swimming from Africa, followed by a reconfiguration to present-day flow 15–20 million years ago that significantly diminished the ability for transoceanic dispersal to Madagascar from the adjacent mainland. PMID:22431643

  15. Distributional patterns of cecropia (Cecropiaceae: a panbiogeographic analysis

    Directory of Open Access Journals (Sweden)

    Franco Rosselli Pilar

    1997-06-01

    Full Text Available A panbiogeographic analysis of the distributional patterns of 60 species of Cecropia was carried out. Based on the distributional ranges of 36 species, we found eight generalized tracks for Cecropia species. whereas distributional patterns of 24 species were uninformative for the analysis. The major concentration of species of Cecropia is in the Neotropical Andean region. where there are three generalized tracks and two nodes. The northern Andes in Colombia and Ecuador are richer than the Central Andes in Perú. they contain two generalized tracks; one to the west and another to the east, formed by individual tracks of eight species each. There are four generalized tracks outside the Andean region: two in the Amazonian region in Guayana-Pará and in Manaus. one in Roraima. one in Serra do Mar in the Atlantic forest of Brazil and one in Central America. Speciation in Cecropia may be related to the Andean first uplift.Con base en la distribución de 60 especies del género Cecropia, se hizo un análisis panbiogeográfico. Se construyeron 8 trazos generalizados con base en el patrón de distribución de 36 especies; la distribución de las demás especies no aportaba información para la definición de los trazos. La región andina tiene la mayor concentración de especies de Cecropia representada por la presencia de tres trazos generalizados y dos nodos; los dos trazos con mayor número de especies se localizan en su parte norte, en Colombia y Ecuador y el otro en los Andes centrales en Perú. Se encontraron además, cuatro trazos extrandinos: dos en la región amazónica, en Pará-Guayana y en Manaus, uno en Roraima, uno en Serra do Mar en la Selva Atlánfíca del Brasil y uno en Centro América. La especiación en Cecropia parece estar relacionada con el primer levantamiento de los Andes.

  16. Habitat characteristics predicting distribution and abundance patterns of scallops in D'Entrecasteaux Channel, Tasmania.

    Science.gov (United States)

    Mendo, Tania; Lyle, Jeremy M; Moltschaniwskyj, Natalie A; Tracey, Sean R; Semmens, Jayson M

    2014-01-01

    Habitat characteristics greatly influence the patterns of distribution and abundance in scallops, providing structure for the settlement of spat and influencing predation risk and rates of survival. Establishing scallop-habitat relationships is relevant to understanding the ecological processes that regulate scallop populations and to managing critical habitats. This information is particularly relevant for the D'Entrecasteaux Channel, south-eastern Tasmania (147.335 W, 43.220 S), a region that has supported significant but highly variable scallop production over many years, including protracted periods of stock collapse. Three species of scallops are present in the region; the commercial scallop Pecten fumatus, the queen scallop Equichlamys bifrons, and the doughboy scallop Mimachlamys asperrima. We used dive surveys and Generalized Additive Modelling to examine the relationship between the distribution and abundance patterns of each species and associated habitat characteristics. The aggregated distribution of each species could be predicted as a function of sediment type and species-specific habitat structural components. While P. fumatus was strongly associated with finer sediments and E. bifrons with coarse grain sediments, M. asperrima had a less selective association, possibly related to its ability to attach on a wide range of substrates. Other habitat characteristics explaining P. fumatus abundance were depth, Asterias amurensis abundance, shell and macroalgae cover. Equichlamys bifrons was strongly associated with macroalgae and seagrass cover, whereas M. asperrima abundance was greatly explained by sponge cover. The models define a set of relationships from which plausible hypotheses can be developed. We propose that these relationships are mediated by predation pressure as well as the specific behavioural characteristics of each species. The findings also highlight the specific habitat characteristics that are relevant for spatial management and habitat

  17. Habitat characteristics predicting distribution and abundance patterns of scallops in D'Entrecasteaux Channel, Tasmania.

    Directory of Open Access Journals (Sweden)

    Tania Mendo

    Full Text Available Habitat characteristics greatly influence the patterns of distribution and abundance in scallops, providing structure for the settlement of spat and influencing predation risk and rates of survival. Establishing scallop-habitat relationships is relevant to understanding the ecological processes that regulate scallop populations and to managing critical habitats. This information is particularly relevant for the D'Entrecasteaux Channel, south-eastern Tasmania (147.335 W, 43.220 S, a region that has supported significant but highly variable scallop production over many years, including protracted periods of stock collapse. Three species of scallops are present in the region; the commercial scallop Pecten fumatus, the queen scallop Equichlamys bifrons, and the doughboy scallop Mimachlamys asperrima. We used dive surveys and Generalized Additive Modelling to examine the relationship between the distribution and abundance patterns of each species and associated habitat characteristics. The aggregated distribution of each species could be predicted as a function of sediment type and species-specific habitat structural components. While P. fumatus was strongly associated with finer sediments and E. bifrons with coarse grain sediments, M. asperrima had a less selective association, possibly related to its ability to attach on a wide range of substrates. Other habitat characteristics explaining P. fumatus abundance were depth, Asterias amurensis abundance, shell and macroalgae cover. Equichlamys bifrons was strongly associated with macroalgae and seagrass cover, whereas M. asperrima abundance was greatly explained by sponge cover. The models define a set of relationships from which plausible hypotheses can be developed. We propose that these relationships are mediated by predation pressure as well as the specific behavioural characteristics of each species. The findings also highlight the specific habitat characteristics that are relevant for spatial

  18. Photosynthetic Light Responses May Explain Vertical Distribution of Hymenophyllaceae Species in a Temperate Rainforest of Southern Chile.

    Directory of Open Access Journals (Sweden)

    María José Parra

    Full Text Available Some epiphytic Hymenophyllaceae are restricted to lower parts of the host ( 1000 μmol photons m(-2 s(-1. Our aim was to study the photosynthetic light responses of two Hymenophyllaceae species in relation to their contrasting distribution. We determined light tolerance of Hymenoglossum cruentum and Hymenophyllum dentatum by measuring gas exchange, PSI and PSII light energy partitioning, NPQ components, and pigment contents. H. dentatum showed lower maximum photosynthesis rates (A max than H. cruentum, but the former species kept its net rates (An near Amax across a wide light range. In contrast, in the latter one, An declined at PPFDs > 60 μmol photons m(-2 s(-1. H. cruentum, the shadiest plant, showed higher chlorophyll contents than H. dentatum. Differences in energy partitioning at PSI and PSII were consistent with gas exchange results. H. dentatum exhibited a higher light compensation point of the partitioning of absorbed energy between photochemical Y(PSII and non-photochemical Y(NPQ processes. Hence, both species allocated energy mainly toward photochemistry instead of heat dissipation at their light saturation points. Above saturation, H. cruentum had higher heat dissipation than H. dentatum. PSI yield (YPSI remained higher in H. dentatum than H. cruentum in a wider light range. In both species, the main cause of heat dissipation at PSI was a donor side limitation. An early dynamic photo-inhibition of PSII may have caused an over reduction of the Qa+ pool decreasing the efficiency of electron donation to PSI. In H. dentatum, a slight increase in heat dissipation due to acceptor side limitation of PSI was observed above 300 μmol photons m(-2s(-1. Differences in photosynthetic responses to light suggest that light tolerance and species plasticity could explain their contrasting vertical distribution.

  19. Contrasting the effects of environment, dispersal and biotic interactions to explain the distribution of invasive plants in alpine communities.

    Science.gov (United States)

    Gallien, Laure; Mazel, Florent; Lavergne, Sébastien; Renaud, Julien; Douzet, Rolland; Thuiller, Wilfried

    2015-05-01

    Despite considerable efforts devoted to investigate the community assembly processes driving plant invasions, few general conclusions have been drawn so far. Three main processes, generally acting as successive filters, are thought to be of prime importance. The invader has to disperse (1st filter) into a suitable environment (2nd filter) and succeed in establishing in recipient communities through competitive interactions (3rd filter) using two strategies: competition avoidance by the use of different resources (resource opportunity), or competitive exclusion of native species. Surprisingly, despite the general consensus on the importance of investigating these three processes and their interplay, they are usually studied independently. Here we aim to analyse these three filters together, by including them all: abiotic environment, dispersal and biotic interactions, into models of invasive species distributions. We first propose a suite of indices (based on species functional dissimilarities) supposed to reflect the two competitive strategies (resource opportunity and competition exclusion). Then, we use a set of generalised linear models to explain the distribution of seven herbaceous invaders in natural communities (using a large vegetation database for the French Alps containing 5,000 community-plots). Finally, we measure the relative importance of competitive interaction indices, identify the type of coexistence mechanism involved and how this varies along environmental gradients. Adding competition indices significantly improved model's performance, but neither resource opportunity nor competitive exclusion were common strategies among the seven species. Overall, we show that combining environmental, dispersal and biotic information to model invasions has excellent potential for improving our understanding of invader success.

  20. Can a one-layer optical skin model including melanin and inhomogeneously distributed blood explain spatially resolved diffuse reflectance spectra?

    Science.gov (United States)

    Karlsson, Hanna; Pettersson, Anders; Larsson, Marcus; Strömberg, Tomas

    2011-02-01

    Model based analysis of calibrated diffuse reflectance spectroscopy can be used for determining oxygenation and concentration of skin chromophores. This study aimed at assessing the effect of including melanin in addition to hemoglobin (Hb) as chromophores and compensating for inhomogeneously distributed blood (vessel packaging), in a single-layer skin model. Spectra from four humans were collected during different provocations using a twochannel fiber optic probe with source-detector separations 0.4 and 1.2 mm. Absolute calibrated spectra using data from either a single distance or both distances were analyzed using inverse Monte Carlo for light transport and Levenberg-Marquardt for non-linear fitting. The model fitting was excellent using a single distance. However, the estimated model failed to explain spectra from the other distance. The two-distance model did not fit the data well at either distance. Model fitting was significantly improved including melanin and vessel packaging. The most prominent effect when fitting data from the larger separation compared to the smaller separation was a different light scattering decay with wavelength, while the tissue fraction of Hb and saturation were similar. For modeling spectra at both distances, we propose using either a multi-layer skin model or a more advanced model for the scattering phase function.

  1. Satellite Image Edge Detection for Population Distribution Pattern Identification using Levelset with Morphological Filtering Process

    Science.gov (United States)

    Harsiti; Munandar, T. A.; Suhendar, A.; Abdullah, A. G.; Rohendi, D.

    2017-03-01

    Population distribution pattern is directly related with economic gap of a region. Analysis of population distribution pattern is usually performed by studying statistical data on population. This study aimed to analyze population distribution pattern using image analysis concept, i.e. using satellite images. Levelset and morphological image filtering methods were used to analyze images to see distribution pattern. The research result showed that Levelset and morphological image filtering could remove a lot of noises in analysis result images and form object edge contours very clearly. The detected object contours were used as references to recognize population distribution pattern based on satellite image analysis. The pattern made based on the research result didn’t show optimal result because Levelset performed image segmentation based on the contours of the analyzed objects. Other segmentation methods should be combined with it to produce clearer population distribution pattern.

  2. Distribution pattern of cholinesterase enzymes in human tooth germs.

    Science.gov (United States)

    Nandasena, T L; Jayawardena, C K; Tilakaratne, W M; Nanayakkara, C D

    2010-08-01

    The two distinct molecular forms of cholinesterase (ChE) are acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Our previous studies have reported that ChE is involved in tooth development. However, further experiments are needed to understand the precise action of ChE in tooth development. This study aimed to localise types of ChE in human tooth germs, and identify their distribution pattern. ChE were localised in frozen sections of jaws which were prepared from dead fetuses, neonates and stillborns who were free from visible abnormalities by Karnovsky and Root method. AChE was identified in the inner and outer enamel epithelia including the cervical loop region, stratum intermedium and preameloblasts of tooth germs at bell stage. Secretory ameloblasts were free from staining. The bud and cap stages of permanent tooth germs showed AChE activity on the lingual aspect and top surface of the epithelial ingrowths, respectively. BuChE activity was localised in the degenerating dental lamina. Our study reported the first evidence of localisation of ChE in human tooth development and identified the possible molecular form of ChE in tooth germs as AChE. Also, our results have provided strong evidence to speculate the action of AChE is on the cells of enamel organ during tooth development.

  3. Phylogeography of Yersinia ruckeri reveals effects of past evolutionary events on the current strain distribution and explains variations in the global transmission of Enteric Redmouth (ERM disease.

    Directory of Open Access Journals (Sweden)

    Asmine eBastardo

    2015-10-01

    Full Text Available Phylogeographic patterns and population genetic structure of Yersinia ruckeri, the pathological agent of enteric redmouth disease (ERM in salmonids, were investigated on the basis of concatenated multiloci sequences from isolates of different phenotypes obtained between 1965-2009 from diverse areas and hosts. Sequence analyses revealed genetic differentiation among subpopulations with the largest genetic distance occurring between subpopulations of Europe and Canada and/or South America. Bayesian analysis indicated the presence of three ancestral population clusters. Mismatch distribution displayed signatures characteristic of changes in size due to demographic and spatial expansions in the overall Y. ruckeri population, and also in the geographically separate subpopulations. Furthermore, a weak signal of isolation by distance was determined. A significant positive correlation between genetic and geographical distances was observed. These results revealed that the population of Y. ruckeri has undergone both ancient and recent population changes that were probably induced by biogeography forces in the past and, much more recently, by adaptive processes forced by aquaculture expansion. These findings have important implications for future studies on Y. ruckeri population dynamics, on the potential role of genetic structure to explain variations in ERM transmission, and on the effect of past evolutionary events on current estimations of gene flow.

  4. Distributed Patterns of Brain Activity Underlying Real-Time fMRI Neurofeedback Training.

    Science.gov (United States)

    Kopel, Rotem; Emmert, Kirsten; Scharnowski, Frank; Haller, Sven; Van De Ville, Dimitri

    2017-06-01

    Neurofeedback (NF) based on real-time functional magnetic resonance imaging (rt-fMRI) is an exciting neuroimaging application. In most rt-fMRI NF studies, the activity level of a single region of interest (ROI) is provided as a feedback signal and the participants are trained to up or down regulate the feedback signal. NF training effects are typically analyzed using a confirmatory univariate approach, i.e., changes in the target ROI are explained by a univariate linear modulation. However, learning to self-regulate the ROI activity through NF is mediated by distributed changes across the brain. Here, we deploy a multivariate decoding model for assessing NF training effects across the whole brain. Specifically, we first explain the NF training effect by a posthoc multivariate model that leads to a pattern of coactivation based on 90 functional atlas regions. We then use cross validation to reveal the set of brain regions with the best fit. This novel approach was applied to the data from a rt-fMRI NF study where the participants learned to down regulate the auditory cortex. We found that the optimal model consisted of 16 brain regions whose coactivation patterns best described the training effect over the NF training days. Cross validation of the multivariate model showed that it generalized across the participants. Interestingly, the participants could be clustered into two groups with distinct patterns of coactivation, potentially reflecting different NF learning strategies. Overall, our findings revealed that multiple brain regions are involved in learning to regulate an activity in a single ROI, and thus leading to a better understanding of the mechanisms underlying NF training.

  5. Economic diversification: Explaining the pattern of diversification in the global economy and its implications for fostering diversification in poorer countries

    NARCIS (Netherlands)

    Freire Junior, Clovis

    2017-01-01

    Economic diversification is very relevant for poorer developing countries to create jobs and foster economic development. That need has been recognised in key internationally agreed development goals. The empirical economic literature has identified several stylised facts about the pattern of

  6. Connectivity of vehicular ad hoc networks with continuous node distribution patterns

    OpenAIRE

    Jin, W L; Wang, Bruce

    2010-01-01

    The connectivity of vehicular ad hoc networks (VANets) can be affected by the special distribution patterns, usually dependent and non-uniform, of vehicles in a transportation network. In this study, we introduce a new framework for computing the connectivity in a VANet for continuous distribution patterns of communication nodes on a line in a transportation network. Such distribution patterns can be estimated from traffic densities obtained through loop detectors or other detectors. When com...

  7. Mean Annual Precipitation Explains Spatiotemporal Patterns of Cenozoic Mammal Beta Diversity and Latitudinal Diversity Gradients in North America

    OpenAIRE

    Fraser, D; Hassall, C; Gorelick, R; Rybczynski, N

    2014-01-01

    Spatial diversity patterns are thought to be driven by climate-mediated processes. However, temporal patterns of community composition remain poorly studied. We provide two complementary analyses of North American mammal diversity, using (i) a paleontological dataset (2077 localities with 2493 taxon occurrences) spanning 21 discrete subdivisions of the Cenozoic based on North American Land Mammal Ages (36 Ma--present), and (ii) climate space model predictions for 744 extant mammals under eigh...

  8. The relative importance of socioeconomic indicators in explaining differences in BMI and waist:hip ratio, and the mediating effect of work control, dietary patterns and physical activity.

    Science.gov (United States)

    Kjøllesdal, Marte Råberg; Holmboe-Ottesen, Gerd; Mosdøl, Annhild; Wandel, Margareta

    2010-10-01

    Socioeconomic differences in overweight are well documented, but most studies have only used one or two indicators of socioeconomic position (SEP). The aim of the present study was to explore the relative importance of indicators of SEP (occupation, education and income) in explaining variation in BMI and waist:hip ratio (WHR), and the mediating effect of work control and lifestyle factors (dietary patterns, smoking and physical activity). The Oslo Health Study, a cross-sectional study, was carried out in 2000-1, Oslo, Norway. Our sample included 9235 adult working Oslo citizens, who attended a health examination and filled in two complementary FFQ with < 20% missing responses to food items. Four dietary patterns were identified through factor analysis, and were named 'modern', 'Western', 'traditional' and 'sweet'. In multivariate models, BMI and WHR were inversely associated with education (P < 0.001/P < 0.001) and occupation (P = 0.002/P < 0.001), whereas there were no significant associations with income or the work control. The 'modern' (P < 0.001) and the 'sweet' (P < 0.001) dietary patterns and physical activity level (P < 0.001) were inversely associated, while the 'Western' dietary pattern (P < 0.001) was positively associated with both BMI and WHR. These lifestyle factors could not fully explain the socioeconomic differences in BMI or WHR. However, together with socioeconomic factors, they explained more of the variation in WHR among men (21%) than among women (7%).

  9. Modelling spatiotemporal distribution patterns of earthworms in order to indicate hydrological soil processes

    Science.gov (United States)

    Palm, Juliane; Klaus, Julian; van Schaik, Loes; Zehe, Erwin; Schröder, Boris

    2010-05-01

    environmental predictors which explain the distribution and dynamics of different ecological earthworm types can help us to understand where or when these processes are relevant in the landscape. Therefore, we develop species distribution models which are a useful tool to predict spatiotemporal distributions of earthworm occurrence and abundance under changing environmental conditions. On field scale, geostatistical distribution maps have shown that the spatial distribution of earthworms depends on soil parameters such as food supply, soil moisture, bulk density but with different patterns for earthworm stages (adult, juvenile) and ecological types (anecic, endogeic, epigeic). On landscape scales, earthworm distribution seems to be strongly controlled by management/disturbance-related factors. Our study shows different modelling approaches for predicting distribution patterns of earthworms in the Weiherbach area, an agricultural site in Kraichtal (Baden-Württemberg, Germany). We carried out field studies on arable fields differing in soil management practices (conventional, conservational), soil properties (organic matter content, texture, soil moisture), and topography (slope, elevation) in order to identify predictors for earthworm occurrence, abundance and biomass. Our earthworm distribution models consider all ecological groups as well as different life stages, accounting for the fact that the activity of juveniles is sometimes different from those of adults. Within our BIOPORE-project it is our final goal to couple our distribution models with population dynamic models and a preferential flow model to an integrated ecohydrological model to analyse feedbacks between earthworm engineering and transport characteristics affecting the functioning of (agro-) ecosystems.

  10. Leaf gas exchange and nutrient use efficiency help explain the distribution of two Neotropical mangroves under contrasting flooding and salinity

    Science.gov (United States)

    Cardona-Olarte, Pablo; Krauss, Ken W.; Twilley, Robert R.

    2013-01-01

    Rhizophora mangle and Laguncularia racemosa co-occur along many intertidal floodplains in the Neotropics. Their patterns of dominance shift along various gradients, coincident with salinity, soil fertility, and tidal flooding. We used leaf gas exchange metrics to investigate the strategies of these two species in mixed culture to simulate competition under different salinity concentrations and hydroperiods. Semidiurnal tidal and permanent flooding hydroperiods at two constant salinity regimes (10 g L−1 and 40 g L−1) were simulated over 10 months. Assimilation (A), stomatal conductance (gw), intercellular CO2 concentration (Ci), instantaneous photosynthetic water use efficiency (PWUE), and photosynthetic nitrogen use efficiency (PNUE) were determined at the leaf level for both species over two time periods. Rhizophora mangle had significantly higher PWUE than did L. racemosa seedlings at low salinities; however, L. racemosa had higher PNUE and stomatal conductance and gw, accordingly, had greater intercellular CO2 (calculated) during measurements. Both species maintained similar capacities for assimilation at 10 and 40 g L−1 salinity and during both permanent and tidal hydroperiod treatments. Hydroperiod alone had no detectable effect on leaf gas exchange. However, PWUE increased and PNUE decreased for both species at 40 g L−1 salinity compared to 10 g L−1. At 40 g L−1 salinity, PNUE was higher for L. racemosa than R. mangle with tidal flooding. These treatments indicated that salinity influences gas exchange efficiency, might affect how gases are apportioned intercellularly, and accentuates different strategies for distributing leaf nitrogen to photosynthesis for these two species while growing competitively.

  11. Leaf Gas Exchange and Nutrient Use Efficiency Help Explain the Distribution of Two Neotropical Mangroves under Contrasting Flooding and Salinity

    Directory of Open Access Journals (Sweden)

    Pablo Cardona-Olarte

    2013-01-01

    Full Text Available Rhizophora mangle and Laguncularia racemosa cooccur along many intertidal floodplains in the Neotropics. Their patterns of dominance shift along various gradients, coincident with salinity, soil fertility, and tidal flooding. We used leaf gas exchange metrics to investigate the strategies of these two species in mixed culture to simulate competition under different salinity concentrations and hydroperiods. Semidiurnal tidal and permanent flooding hydroperiods at two constant salinity regimes (10 g L−1 and 40 g L−1 were simulated over 10 months. Assimilation (A, stomatal conductance (gw, intercellular CO2 concentration (Ci, instantaneous photosynthetic water use efficiency (PWUE, and photosynthetic nitrogen use efficiency (PNUE were determined at the leaf level for both species over two time periods. Rhizophora mangle had significantly higher PWUE than did L. racemosa seedlings at low salinities; however, L. racemosa had higher PNUE and gw and, accordingly, had greater intercellular CO2 (calculated during measurements. Both species maintained similar capacities for A at 10 and 40 g L−1 salinity and during both permanent and tidal hydroperiod treatments. Hydroperiod alone had no detectable effect on leaf gas exchange. However, PWUE increased and PNUE decreased for both species at 40 g L−1 salinity compared to 10 g L−1. At 40 g L−1 salinity, PNUE was higher for L. racemosa than R. mangle with tidal flooding. These treatments indicated that salinity influences gas exchange efficiency, might affect how gases are apportioned intercellularly, and accentuates different strategies for distributing leaf nitrogen to photosynthesis for these two species while growing competitively.

  12. A dated phylogeny complements macroecological analysis to explain the diversity patterns in Geonoma (Arecaceae)

    DEFF Research Database (Denmark)

    Roncal, Julissa; Overgaard, Anne Blach; Borchsenius, Finn

    2011-01-01

    pattern. To test for a time-for-diversification effect, we correlated four different species richness measures with the diversification time of the earliest large lineage that is characteristic of each cluster. In support of this hypothesis, we found that geographic areas with higher richness contained...... in the Geonoma phylogeny. Finally, we used a dated phylogeny to assess whether species richness within the floristic clusters was constrained by a specific historical biogeographic driver, namely time-for-diversification. A cluster analysis identified six spatially coherent floristic clusters, four of which were......Integrating phylogenetic data into macroecological studies of biodiversity patterns may complement the information provided by present-day spatial patterns. In the present study, we used range map data for all Geonoma (Arecaceae) species to assess whether Geonoma species composition forms spatially...

  13. Spatial patterns of zooplankton distribution and abundance in ...

    African Journals Online (AJOL)

    Spatial patterns and abundance of zooplankton in aquatic habitats are important determinants for production of fish species, invertebrates and availability of phytoplankton. Weekly monitoring for zooplankton abundance was conducted in Shirati Bay, Lake Victoria, to explore their spatial patterns in relation to phytoplankton, ...

  14. Does Glycosylation as a modifier of Original Antigenic Sin explain the case age distribution and unusual toxicity in pandemic novel H1N1 influenza?

    Directory of Open Access Journals (Sweden)

    Nishiura Hiroshi

    2010-01-01

    Full Text Available Abstract Background A pandemic novel H1N1 swine-origin influenza virus has emerged. Most recently the World Health Organization has announced that in a country-dependent fashion, up to 15% of cases may require hospitalization, often including respiratory support. It is now clear that healthy children and young adults are disproportionately affected, most unusually among those with severe respiratory disease without underlying conditions. One possible explanation for this case age distribution is the doctrine of Original Antigenic Sin, i.e., novel H1N1 may be antigenically similar to H1N1 viruses that circulated at an earlier time. Persons whose first exposure to influenza viruses was to such similar viruses would be relatively immune. However, this principle is not sufficient to explain the graded susceptibility between ages 20 and 60, the reduced susceptibility in children below age 10, and the unusual toxicity observed. Methods We collected case data from 11 countries, about 60% of all cases reported through mid-July 2009. We compared sequence data for the hemagglutinin of novel H1N1 with sequences of H1N1 viruses from 1918 to the present. We searched for sequence differences that imply loss of antigenicity either directly through amino acid substitution or by the appearance of sites for potential glycosylation proximal to sites known to be antigenic in humans. We also considered T-cell epitopes. Results In our composite, over 75% of confirmed cases of novel H1N1 occurred in persons ≤ 30 years old, with peak incidence in the age range 10-19 years. Less than 3% of cases occurred in persons over 65, with a gradation in incidence between ages 20 and 60 years. The sequence data indicates that novel H1N1 is most similar to H1N1 viruses that circulated before 1943. Novel H1N1 lacks glycosylation sites on the globular head of hemagglutinin (HA1 near antigenic regions, a pattern shared with the 1918 pandemic strain and H1N1 viruses that circulated

  15. Water storage in the lichen genus Usnea in Sweden and Norway : Can morphological and water storage traits explain the distribution and ecology of epiphytic species?

    OpenAIRE

    Eriksson, Amanda

    2015-01-01

    Lichens are poikilohydric and cannot control water uptake and loss, water relations could therefore impact their distribution. This study examines if morphological, anatomical, and water storage traits could explain distribution of epiphytic species in the lichen genus Usnea. Seven species from oceanic (Norway) and continental areas (Sweden) were studied. Total, internal, and external water holding capacity (WHC, mg H2O cm-2) along with relative water content (WC) were recorded by spraying th...

  16. Unravelling a biogeographical knot: origin of the 'leapfrog' distribution pattern of Australo-Papuan sooty owls (Strigiformes) and logrunners (Passeriformes).

    Science.gov (United States)

    Norman, J A; Christidis, L; Joseph, L; Slikas, B; Alpers, D

    2002-10-22

    Molecular analysis of two Australo-Papuan rainforest birds exhibiting correlated 'leapfrog' patterns were used to elucidate the evolutionary origin of this unusual pattern of geographical differentiation. In both sooty owls (Tyto) and logrunners (Orthonyx), phenotypically similar populations occupy widely disjunct areas (central-eastern Australia and upland New Guinea) with a third, highly distinctive population, occurring between them in northeastern Queensland. Two mechanisms have been proposed to explain the origin of leapfrog patterns in avian distributions: recent shared ancestry of terminal populations and unequal rates or phenotypic change among populations. As the former should generate correlated patterns of phenotypic and genetic differentiation, we tested for a sister relationship between populations from New Guinea and central-eastern Australia using nuclear and mitochondrial DNA sequences. The resulting phylogenies not only refute recent ancestry as an explanation for the leapfrog pattern, but provide evidence of vastly different spatio-temporal histories for sooty owls and logrunners within the Australo-Papuan rainforests. This incongruence indicates that the evolutionary processes responsible for generating leapfrog patterns in these co-distributed taxa are complex, possibly involving a combination of selection and drift in sooty owls and convergence or retention of ancestral characteristics in logrunners.

  17. Recognition of distinctive patterns of gallium-67 distribution in sarcoidosis

    Energy Technology Data Exchange (ETDEWEB)

    Sulavik, S.B.; Spencer, R.P.; Weed, D.A.; Shapiro, H.R.; Shiue, S.T.; Castriotta, R.J. (Univ. of Connecticut School of Medicine, Farmington (USA))

    1990-12-01

    Assessment of gallium-67 ({sup 67}Ga) uptake in the salivary and lacrimal glands and intrathoracic lymph nodes was made in 605 consecutive patients including 65 with sarcoidosis. A distinctive intrathoracic lymph node {sup 67}Ga uptake pattern, resembling the Greek letter lambda, was observed only in sarcoidosis (72%). Symmetrical lacrimal gland and parotid gland {sup 67}Ga uptake (panda appearance) was noted in 79% of sarcoidosis patients. A simultaneous lambda and panda pattern (62%) or a panda appearance with radiographic bilateral, symmetrical, hilar lymphadenopathy (6%) was present only in sarcoidosis patients. The presence of either of these patterns was particularly prevalent in roentgen Stages I (80%) or II (74%). We conclude that simultaneous (a) lambda and panda images, or (b) a panda image with bilateral symmetrical hilar lymphadenopathy on chest X-ray represent distinctive patterns which are highly specific for sarcoidosis, and may obviate the need for invasive diagnostic procedures.

  18. Distribution patterns of the ghost crab Ocypode cursor on sandy ...

    African Journals Online (AJOL)

    The spatial distribution of the ghost crab Ocypode cursor was determined for beaches on eastern Boa Vista Island, Cabo Verde Archipelago. The main objectives were to analyse the across-shore distribution by means of burrow counts and to identify preferential zones and spatial segregation. Six beaches were investigated ...

  19. Contrasting distribution patterns of invasive and naturalized non-native species along environmental gradients in a semi-arid montane ecosystem

    Science.gov (United States)

    Kelly M. Andersen; Bridgett J. Naylor; Bryan A. Endress; Catherine G. Parks

    2015-01-01

    Questions: Mountain systems have high abiotic heterogeneity over local spatial scales, offering natural experiments for examining plant species invasions. We ask whether functional groupings explain non-native species spread into native vegetation and up elevation gradients.We examine whether non-native species distribution patterns are related to environmental...

  20. Development of a dynamic framework to explain population patterns of leisure-time physical activity through agent-based modeling.

    Science.gov (United States)

    Garcia, Leandro M T; Diez Roux, Ana V; Martins, André C R; Yang, Yong; Florindo, Alex A

    2017-08-22

    Despite the increasing body of evidences on the factors influencing leisure-time physical activity, our understanding of the mechanisms and interactions that lead to the formation and evolution of population patterns is still limited. Moreover, most frameworks in this field fail to capture dynamic processes. Our aim was to create a dynamic conceptual model depicting the interaction between key psychological attributes of individuals and main aspects of the built and social environments in which they live. This conceptual model will inform and support the development of an agent-based model aimed to explore how population patterns of LTPA in adults may emerge from the dynamic interplay between psychological traits and built and social environments. We integrated existing theories and models as well as available empirical data (both from literature reviews), and expert opinions (based on a systematic expert assessment of an intermediary version of the model). The model explicitly presents intention as the proximal determinant of leisure-time physical activity, a relationship dynamically moderated by the built environment (access, quality, and available activities) - with the strength of the moderation varying as a function of the person's intention- and influenced both by the social environment (proximal network's and community's behavior) and the person's behavior. Our conceptual model is well supported by evidence and experts' opinions and will inform the design of our agent-based model, as well as data collection and analysis of future investigations on population patterns of leisure-time physical activity among adults.

  1. Gastrointestinal lymphoma in Western Algeria: pattern of distribution and histological subtypes (retrospective study).

    Science.gov (United States)

    Zeggai, Soumia; Harir, Noria; Tou, Abdenacer; Medjamia, Miloud; Guenaoui, Khaira

    2016-12-01

    Primary gastrointestinal (GI) lymphomas (GIL) are uncommon diseases that can involve the whole GI tract. Considerable variation exists in the literature with respect to incidence of the various histological subtypes and sites of involvement. This study was undertaken to establish the anatomic distribution, histological subtypes and sites of GI lymphomas of patients from Western Algeria. The case records of 58 consecutive patients with GIL diagnosed at the Pathologies Departments of Algerian west region (the Military Hospital of Oran city and the Central University Hospital of Sidi Bel Abbes city) from January 2006 to December 2013 were retrospectively evaluated for epidemiology and histopathology report. All lymphomas were reclassified according to the WHO 2008 classification. A total of 58 patients (39 male, 19 female) with mean age of 61 years and a range of 20-89 years were included in this study. Stomach was the most common site involved (70.7%). The commonest histological subtype was mucosa-associated lymphoid tissue (MALT) B cell lymphoma (46.6%), followed by diffuse large B-cell lymphomas (DLBCL) (43.1%).The frequency of Helicobacter pylori (HP) positivity differ between gastric and intestinal location P=0.003 and correlates with the histological type P=0.01. This retrospective study of patients with GI lymphoma from Western Algeria illustrates the pattern of distribution of various common and rare histological subtypes. More studies are necessary to find a potential cause, risk factor or genetic mutation that can explain these specific characteristics of GIL.

  2. Hendra virus survival does not explain spillover patterns and implicates relatively direct transmission routes from flying foxes to horses.

    Science.gov (United States)

    Martin, Gerardo; Plowright, Raina; Chen, Carla; Kault, David; Selleck, Paul; Skerratt, Lee F

    2015-06-01

    Hendra virus (HeV) is lethal to humans and horses, and little is known about its epidemiology. Biosecurity restrictions impede advances, particularly on understanding pathways of transmission. Quantifying the environmental survival of HeV can be used for making decisions and to infer transmission pathways. We estimated HeV survival with a Weibull distribution and calculated parameters from data generated in laboratory experiments. HeV survival rates based on air temperatures 24 h after excretion ranged from 2 to 10 % in summer and from 12 to 33 % in winter. Simulated survival across the distribution of the black flying fox (Pteropus alecto), a key reservoir host, did not predict spillover events. Based on our analyses we concluded that the most likely pathways of transmission did not require long periods of virus survival and were likely to involve relatively direct contact with flying fox excreta shortly after excretion. © 2015 The Authors.

  3. Spatial and temporal patterns of carabid activity-density in cereals do not explain levels of predation on weed seeds.

    Science.gov (United States)

    Saska, P; van der Werf, W; de Vries, E; Westerman, P R

    2008-04-01

    Seed predation is an important component of seed mortality of weeds in agro-ecosystems, but the agronomic use and management of this natural weed suppression is hampered by a lack of insight in the underlying ecological processes. In this paper, we investigate whether and how spatial and temporal variation in activity-density of granivorous ground beetles (Coleoptera: Carabidae) results in a corresponding pattern of seed predation. Activity-density of carabids was measured by using pitfall traps in two organic winter wheat fields from March to July 2004. Predation of seeds (Capsella bursa-pastoris, Lamium amplexicaule, Poa annua and Stellaria media) was assessed using seed cards at the same sites and times. As measured by pitfall traps, carabids were the dominant group of insects that had access to the seed cards. In the field, predation of the four different species of seed was in the order: C. bursa-pastoris>P. annua>S. media>L. amplexicaule; and this order of preference was confirmed in the laboratory using the dominant species of carabid. On average, seed predation was higher in the field interior compared to the edge, whereas catches of carabids were highest near the edge. Weeks with elevated seed predation did not concur with high activity-density of carabids. Thus, patterns of spatial and temporal variation in seed predation were not matched by similar patterns in the abundance of granivorous carabid beetles. The lack of correspondence is ascribed to effects of confounding factors, such as weather, the background density of seeds, the composition of the carabid community, and the phenology and physiological state of the beetles. Our results show that differences in seed loss among weed species may be predicted from laboratory trials on preference. However, predator activity-density, as measured in pitfall traps, is an insufficient predictor of seed predation over time and space within a field.

  4. Distributional patterns of the American Peiratinae (Heteroptera: Reduviidae)

    NARCIS (Netherlands)

    Morrone, J.J.; Coscarón, del C M.

    1996-01-01

    Based on distributional data of 40 species of Peiratinae, historical relationships of five Amazonian areas (Paranaense, Atlantic, Pacific, Amazonian, and Cerrado) and two Chacoan areas (Chaco and Caatinga), were investigated through a parsimony analysis of endemicity (PAE). The resulting area

  5. Elevational gradients in fish diversity in the Himalaya: water discharge is the key driver of distribution patterns.

    Directory of Open Access Journals (Sweden)

    Jay P Bhatt

    Full Text Available BACKGROUND: Studying diversity and distribution patterns of species along elevational gradients and understanding drivers behind these patterns is central to macroecology and conservation biology. A number of studies on biogeographic gradients are available for terrestrial ecosystems, but freshwater ecosystems remain largely neglected. In particular, we know very little about the species richness gradients and their drivers in the Himalaya, a global biodiversity hotspot. METHODOLOGY/PRINCIPAL FINDINGS: We collated taxonomic and distribution data of fish species from 16 freshwater Himalayan rivers and carried out empirical studies on environmental drivers and fish diversity and distribution in the Teesta river (Eastern Himalaya. We examined patterns of fish species richness along the Himalayan elevational gradients (50-3800 m and sought to understand the drivers behind the emerging patterns. We used generalized linear models (GLM and generalized additive models (GAM to examine the richness patterns; GLM was used to investigate relationship between fish species richness and various environmental variables. Regression modelling involved stepwise procedures, including elimination of collinear variables, best model selection, based on the least Akaike's information criterion (AIC and the highest percentage of deviance explained (D(2. This maiden study on the Himalayan fishes revealed that total and non-endemic fish species richness monotonously decrease with increasing elevation, while endemics peaked around mid elevations (700-1500 m. The best explanatory model (synthetic model indicated that water discharge is the best predictor of fish species richness patterns in the Himalayan rivers. CONCLUSIONS/SIGNIFICANCE: This study, carried out along one of the longest bioclimatic elevation gradients of the world, lends support to Rapoport's elevational rule as opposed to mid domain effect hypothesis. We propose a species-discharge model and contradict

  6. Elevational gradients in fish diversity in the Himalaya: water discharge is the key driver of distribution patterns.

    Science.gov (United States)

    Bhatt, Jay P; Manish, Kumar; Pandit, Maharaj K

    2012-01-01

    Studying diversity and distribution patterns of species along elevational gradients and understanding drivers behind these patterns is central to macroecology and conservation biology. A number of studies on biogeographic gradients are available for terrestrial ecosystems, but freshwater ecosystems remain largely neglected. In particular, we know very little about the species richness gradients and their drivers in the Himalaya, a global biodiversity hotspot. We collated taxonomic and distribution data of fish species from 16 freshwater Himalayan rivers and carried out empirical studies on environmental drivers and fish diversity and distribution in the Teesta river (Eastern Himalaya). We examined patterns of fish species richness along the Himalayan elevational gradients (50-3800 m) and sought to understand the drivers behind the emerging patterns. We used generalized linear models (GLM) and generalized additive models (GAM) to examine the richness patterns; GLM was used to investigate relationship between fish species richness and various environmental variables. Regression modelling involved stepwise procedures, including elimination of collinear variables, best model selection, based on the least Akaike's information criterion (AIC) and the highest percentage of deviance explained (D(2)). This maiden study on the Himalayan fishes revealed that total and non-endemic fish species richness monotonously decrease with increasing elevation, while endemics peaked around mid elevations (700-1500 m). The best explanatory model (synthetic model) indicated that water discharge is the best predictor of fish species richness patterns in the Himalayan rivers. This study, carried out along one of the longest bioclimatic elevation gradients of the world, lends support to Rapoport's elevational rule as opposed to mid domain effect hypothesis. We propose a species-discharge model and contradict species-area model in predicting fish species richness. We suggest that drivers of

  7. Spatio-temporal pattern of rainfall distribution over Ilorin metropolis ...

    African Journals Online (AJOL)

    Rainfall varies over time and space and the study of its variability cannot be over emphasized. This paper examines spatio-temporal patterns of rainfall in Ilorin metropolis, Nigeria. 30 years data were collected in 3 locations [Nigeria Meteorological Agency (NIMET), Lower Niger River Basin Development Authority (LNRBDA) ...

  8. Phylogenetic tests of distribution patterns in South Asia: towards an ...

    Indian Academy of Sciences (India)

    Madhu

    In the last few decades, significant progress has been made in this field due to the infusion of phylogenetic systematics* (Crisci et al 2003; Lomolino and Heaney 2004). Phylogenetic analyses allow inferences about the pattern and time scale of divergence between lineages and postulation of historical processes at levels.

  9. Assessment of Dermatoglyphic Patterns and Sex Distribution in ...

    African Journals Online (AJOL)

    This study was carried out to find out the possibility of a unique pattern of palm and finger prints (Dermatoglyphics) among 192 adults (96 males and 96 females) of Esan origin who, at the time of this study, were residing in Esan-land - the central senatorial district of Edo state, Nigeria. The subjects were selected via ...

  10. Distribution of strain patterns in children with dilated cardiomyopathy.

    Science.gov (United States)

    den Boer, Susanna L; du Marchie Sarvaas, Gideon J; Klitsie, Liselotte M; van Iperen, Gabriëlle G; Tanke, Ronald B; Helbing, Willem A; Backx, Ad P C M; Rammeloo, Lukas A J; Dalinghaus, Michiel; Ten Harkel, Arend D J

    2017-06-01

    This study aimed to evaluate the predicting value of quantitative and qualitative dyssynchrony parameters as assessed by two-dimensional speckle tracking echocardiography (STE) on outcome in children with dilated cardiomyopathy (DCM). Furthermore, the reproducibility of these parameters was investigated. In previous studies in adults with heart failure, several dyssynchrony parameters have been shown to be a valuable predictor of clinical outcome. This multicenter, prospective study included 75 children with DCM and 75 healthy age-matched controls. Using STE, quantitative (time to global peak strain and parameters describing intraventricular time differences) and qualitative dyssynchrony parameters (pattern analysis) of the apical four-chamber, three-chamber, two-chamber views, and the short axis of the left ventricle were assessed. Cox regression was used to identify risk factors for the primary endpoints of death or heart transplantation. Inter-observer and intra-observer variability were described. During a median of 21 months follow-up, 10 patients (13%) reached an endpoint. Although quantitative dyssynchrony measures were higher in patients as compared to controls, the inter-observer and intra-observer variability were high. Pattern analysis showed mainly reduced strain, instead of dyssynchronous patterns. In this study, quantitative dyssynchrony parameters were not reproducible, precluding their use in children. Qualitative pattern analysis showed predominantly reduced strain, suggesting that in children with DCM dyssynchrony may be a minor problem. © 2017, Wiley Periodicals, Inc.

  11. Distribution patterns of striped mullet Mugil cephalus in mangrove ...

    African Journals Online (AJOL)

    The density of juvenile mullet differed significantly among the creeks, but the spatial patterns within them were consistent with higher densities upstream in three of ... striped mullet vary among sites and creeks in response to refuge availability from turbid, shallow water and the accessibility of food from benthic microalgae.

  12. Species distribution and antifungal sensitivity patterns of vaginal ...

    African Journals Online (AJOL)

    Objectives: To identify yeast isolates in vaginal specimens to species level and determine their antifungal susceptibility patterns. Design: Cross-sectional laboratory-based study. Setting: The Aga Khan University Hospital (AKUH), Nairobi. Subjects: Yeast isolates from high vaginal swabs presented to the laboratory for ...

  13. Photosynthetic Light Responses May Explain Vertical Distribution of Hymenophyllaceae Species in a Temperate Rainforest of Southern Chile

    National Research Council Canada - National Science Library

    Parra, María José; Acuña, Karina I; Sierra-Almeida, Angela; Sanfuentes, Camila; Saldaña, Alfredo; Corcuera, Luis J; Bravo, León A

    2015-01-01

    ...; other species occupy the whole host height (≥ 10 m; max PPFD > 1000 μmol photons m(-2) s(-1)). Our aim was to study the photosynthetic light responses of two Hymenophyllaceae species in relation to their contrasting distribution...

  14. Ethnic differences in maternal dietary patterns are largely explained by socio-economic score and integration score: a population-based study.

    Science.gov (United States)

    Sommer, Christine; Sletner, Line; Jenum, Anne K; Mørkrid, Kjersti; Andersen, Lene F; Birkeland, Kåre I; Mosdøl, Annhild

    2013-01-01

    The impact of socio-economic position and integration level on the observed ethnic differences in dietary habits has received little attention. To identify and describe dietary patterns in a multi-ethnic population of pregnant women, to explore ethnic differences in odds ratio (OR) for belonging to a dietary pattern, when adjusted for socio-economic status and integration level and to examine whether the dietary patterns were reflected in levels of biomarkers related to obesity and hyperglycaemia. This cross-sectional study was a part of the STORK Groruddalen study. In total, 757 pregnant women, of whom 59% were of a non-Western origin, completed a food frequency questionnaire in gestational week 28±2. Dietary patterns were extracted through cluster analysis using Ward's method. Four robust clusters were identified where cluster 4 was considered the healthier dietary pattern and cluster 1 the least healthy. All non-European women as compared to Europeans had higher OR for belonging to the unhealthier dietary patterns 1-3 vs. cluster 4. Women from the Middle East and Africa had the highest OR, 21.5 (95% CI 10.6-43.7), of falling into cluster 1 vs. 4 as compared to Europeans. The ORs decreased substantially after adjusting for socio-economic score and integration score. A non-European ethnic origin, low socio-economic and integration scores, conduced higher OR for belonging to clusters 1, 2, and 3 as compared to cluster 4. Significant differences in fasting and 2-h glucose, fasting insulin, glycosylated haemoglobin (HbA1c), insulin resistance (HOMA-IR), and total cholesterol were observed across the dietary patterns. After adjusting for ethnicity, differences in fasting insulin (p=0.015) and HOMA-IR (p=0.040) across clusters remained significant, despite low power. The results indicate that socio-economic and integration level may explain a large proportion of the ethnic differences in dietary patterns.

  15. Spatial patterns of distribution and abundance of Harrisia portoricensis, an endangered Caribbean cactus

    Science.gov (United States)

    J. Rojas-Sandoval; E. J. Melendez-Ackerman; NO-VALUE

    2013-01-01

    Aims The spatial distribution of biotic and abiotic factors may play a dominant role in determining the distribution and abundance of plants in arid and semiarid environments. In this study, we evaluated how spatial patterns of microhabitat variables and the degree of spatial dependence of these variables influence the distribution and abundance of the endangered...

  16. Business Pattern of Distributed Energy in Electric Power System Reformation

    Science.gov (United States)

    Liang, YUE; Zhuochu, LIU; Jun, LI; Siwei, LI

    2017-05-01

    Under the trend of the electric power system revolution, the operation mode of micro power grid that including distributed power will be more diversified. User’s demand response and different strategies on electricity all have great influence on the operation of distributed power grid. This paper will not only research sensitive factors of micro power grid operation, but also analyze and calculate the cost and benefit of micro power grid operation upon different types. Then it will build a tech-economic calculation model, which applies to different types of micro power grid under the reformation of electric power system.

  17. Patterns of distribution and conservation status of freshwater fishes ...

    African Journals Online (AJOL)

    The combined fish collection databases of the Albany Museum and the J.L.B. Smith Institute of Ichthyology are used to identify hotspots of endemism and threatened fish distributions in South Africa. Hotspots of fish species richness occur in the north-eastern lowveld sectors of South Africa and along the ecotone between ...

  18. The effect of spatial planning patterns on distribution of pedestrians ...

    African Journals Online (AJOL)

    Such spaces have consequently failed to fulfill the roles ascribed to them and instead have become neglected and unsafe to operate in. Space syntax and structured observation have been used to collect data. Multiple regression analysis establishes that nine public space variables significantly predict the distribution of ...

  19. Petrology and Rare Earth Elements (REE) distribution patterns of ...

    African Journals Online (AJOL)

    Volcanic and intermediate rocks such as basalts, trachyandesites, trachytes, dacites, rhyolites, nepheline syenites and quartz diorites occur within the area intermittently. The distribution of the chondrite normalized values is used to determine the effect due to magmatic fractionation and the crustal contamination. The REE ...

  20. A reverse taxonomic approach to assess macrofaunal distribution patterns in abyssal Pacific polymetallic nodule fields.

    Directory of Open Access Journals (Sweden)

    Annika Janssen

    Full Text Available Heightened interest in the exploitation of deep seafloor minerals is raising questions on the consequences for the resident fauna. Assessing species ranges and determination of processes underlying current species distributions are prerequisites to conservation planning and predicting faunal responses to changing environmental conditions. The abyssal central Pacific nodule belt, located between the Clarion and Clipperton Fracture Zones (CCZ, is an area prospected for mining of polymetallic nodules. We examined variations in genetic diversity and broad-scale connectivity of isopods and polychaetes across the CCZ. Faunal assemblages were studied from two mining claims (the eastern German and French license areas located 1300 km apart and influenced by different productivity regimes. Using a reverse taxonomy approach based on DNA barcoding, we tested to what extent distance and large-scale changes in environmental parameters lead to differentiation in two macrofaunal taxa exhibiting different functions and life-history patterns. A fragment of the mitochondrial gene Cytochrome Oxidase Subunit 1 (COI was analyzed. At a 97% threshold the molecular operational taxonomic units (MOTUs corresponded well to morphological species. Molecular analyses indicated high local and regional diversity mostly because of large numbers of singletons in the samples. Consequently, variation in composition of genotypic clusters between sites was exceedingly large partly due to paucity of deep-sea sampling and faunal patchiness. A higher proportion of wide-ranging species in polychaetes was contrasted with mostly restricted distributions in isopods. Remarkably, several cryptic lineages appeared to be sympatric and occurred in taxa with putatively good dispersal abilities, whereas some brooding lineages revealed broad distributions across the CCZ. Geographic distance could explain variation in faunal connectivity between regions and sites to some extent, while assumed

  1. Chemosymbiotic species from the Gulf of Cadiz (NE Atlantic: distribution, life styles and nutritional patterns

    Directory of Open Access Journals (Sweden)

    C. F. Rodrigues

    2013-04-01

    Full Text Available Previous work in the mud volcanoes from the Gulf of Cadiz (South Iberian Margin revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of these species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (δ13C, δ15N and δ34S and investigate the intra-specific variation of isotope signatures within and between study sites. During our studies, we identified twenty siboglinidae and nine bivalve chemosymbiotic species living in fifteen mud volcanoes. Solemyid bivalves and tubeworms of the genus Siboglinum are widespread in the study area, whereas other species were found in a single mud volcano (e.g. "Bathymodiolus" mauritanicus or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata. Species distribution suggests that different species may adjust their position within the sediment according to their particular needs, and to the intensity and variability of the chemical substrata supply. Tissue stable isotope signatures for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge on distributional patterns and resource partitioning of chemosymbiotic species and highlights how trophic fuelling varies on spatial scales with direct implications to seep assemblages and potentially to the biodiversity of continental margin.

  2. Growing Richer and Taller: Explaining Change in the Distribution of Child Nutritional Status during Vietnam’s Economic Boom

    NARCIS (Netherlands)

    O.A. O'Donnell (Owen); A.L. Nicolas; E.K.A. van Doorslaer (Eddy)

    2006-01-01

    textabstractOver a five-year period in the 1990s Vietnam experienced annual economic growth of more than 8% and a decrease of 15 points in the proportion of children chronically malnourished (stunted). We estimate the extent to which changes in the distribution of child nutritional status can be

  3. Distribution patterns of postmortem damage in human mitochondrial DNA

    DEFF Research Database (Denmark)

    Gilbert, M Thomas P; Willerslev, Eske; Hansen, Anders J

    2002-01-01

    The distribution of postmortem damage in mitochondrial DNA retrieved from 37 ancient human DNA samples was analyzed by cloning and was compared with a selection of published animal data. A relative rate of damage (rho(v)) was calculated for nucleotide positions within the human hypervariable region......, such as MT5, have lower in vivo mutation rates and lower postmortem-damage rates. The postmortem data also identify a possible functional subregion of the HVR1, termed "low-diversity 1," through the lack of sequence damage. The amount of postmortem damage observed in mitochondrial coding regions...

  4. Income distribution patterns from a complete social security database

    CERN Document Server

    Derzsy, N; Santos, M A

    2012-01-01

    We analyze the income distribution of employees for 9 consecutive years (2001-2009) using a complete social security database for an economically important district of Romania. The database contains detailed information on more than half million taxpayers, including their monthly salaries from all employers where they worked. Besides studying the characteristic distribution functions in the high and low/medium income limits, the database allows us a detailed dynamical study by following the time-evolution of the taxpayers income. To our knowledge, this is the first extensive study of this kind (a previous japanese taxpayers survey was limited to two years). In the high income limit we prove once again the validity of Pareto's law, obtaining a perfect scaling on four orders of magnitude in the rank for all the studied years. The obtained Pareto exponents are quite stable with values around $\\alpha \\approx 2.5$, in spite of the fact that during this period the economy developed rapidly and also a financial-econ...

  5. EFFECT OF COST INCREMENT DISTRIBUTION PATTERNS ON THE PERFORMANCE OF JIT SUPPLY CHAIN

    Directory of Open Access Journals (Sweden)

    Ayu Bidiawati J.R

    2008-01-01

    Full Text Available Cost is an important consideration in supply chain (SC optimisation. This is due to emphasis placed on cost reduction in order to optimise profit. Some researchers use cost as one of their performance measures and others propose ways of accurately calculating cost. As product moves across SC, the product cost also increases. This paper studied the effect of cost increment distribution patterns on the performance of a JIT Supply Chain. In particular, it is necessary to know if inventory allocation across SC needs to be modified to accommodate different cost increment distribution patterns. It was found that funnel is still the best card distribution pattern for JIT-SC regardless the cost increment distribution patterns used.

  6. Functional traits variation explains the distribution of Aextoxicon punctatum (Aextoxicaceae in pronounced moisture gradients within fog-dependent forest fragments

    Directory of Open Access Journals (Sweden)

    Beatriz eSalgado-Negret

    2015-07-01

    Full Text Available Climate change and fragmentation are major threats to world forests. Understanding how functional traits related to drought tolerance change across small-scale, pronounced moisture gradients in fragmented forests is important to predict species’ responses to these threats. In the case of Aextoxicon punctatum, a dominant canopy tree in fog-dependent rain forest patches in semiarid Chile, we explored how the magnitude, variability and correlation patterns of leaf and xylem vessel traits and hydraulic conductivity varied across soil moisture gradients established within and among forest patches of different size, which are associated with differences in tree establishment and mortality patterns. Leaf traits varied across soil-moisture gradients produced by fog interception. Trees growing at drier leeward edges showed higher LMA (leaf mass per area, trichome and stomatal density than trees from the wetter core and windward zones. In contrast, xylem vessel traits (vessels diameter and density did not vary producing loss of hydraulic conductivity at drier leeward edges. We also detected higher levels of phenotypic integration and variability at leeward edges. The ability of A. punctatum to modify leaf traits in response to differences in soil moisture availability established over short distances (<500 m facilitates its persistence in contrasting microhabitats within forest patches. However, xylem anatomy showed limited plasticity, which increases cavitation risk at leeward edges. Greater patch fragmentation, together with fluctuations in irradiance and soil moisture in small patches, could result in higher risk of drought-related tree mortality, with profound impacts on hydrological balances at the ecosystem scale.

  7. Can differences in phosphorus uptake kinetics explain the distribution of cattail and sawgrass in the Florida Everglades?

    Science.gov (United States)

    Brix, Hans; Lorenzen, Bent; Mendelssohn, Irving A; McKee, Karen L; Miao, Shili

    2010-02-08

    Cattail (Typha domingensis) has been spreading in phosphorus (P) enriched areas of the oligotrophic Florida Everglades at the expense of sawgrass (Cladium mariscus spp. jamaicense). Abundant evidence in the literature explains how the opportunistic features of Typha might lead to a complete dominance in P-enriched areas. Less clear is how Typha can grow and acquire P at extremely low P levels, which prevail in the unimpacted areas of the Everglades. Apparent P uptake kinetics were measured for intact plants of Cladium and Typha acclimated to low and high P at two levels of oxygen in hydroponic culture. The saturated rate of P uptake was higher in Typha than in Cladium and higher in low-P acclimated plants than in high-P acclimated plants. The affinity for P uptake was two-fold higher in Typha than in Cladium, and two- to three-fold higher for low-P acclimated plants compared to high-P acclimated plants. As Cladium had a greater proportion of its biomass allocated to roots, the overall uptake capacity of the two species at high P did not differ. At low P availability, Typha increased biomass allocation to roots more than Cladium. Both species also adjusted their P uptake kinetics, but Typha more so than Cladium. The adjustment of the P uptake system and increased biomass allocation to roots resulted in a five-fold higher uptake per plant for Cladium and a ten-fold higher uptake for Typha. Both Cladium and Typha adjust P uptake kinetics in relation to plant demand when P availability is high. When P concentrations are low, however, Typha adjusts P uptake kinetics and also increases allocation to roots more so than Cladium, thereby improving both efficiency and capacity of P uptake. Cladium has less need to adjust P uptake kinetics because it is already efficient at acquiring P from peat soils (e.g., through secretion of phosphatases, symbiosis with arbuscular mycorrhizal fungi, nutrient conservation growth traits). Thus, although Cladium and Typha have qualitatively

  8. Can differences in phosphorus uptake kinetics explain the distribution of cattail and sawgrass in the Florida Everglades?

    Directory of Open Access Journals (Sweden)

    McKee Karen L

    2010-02-01

    Full Text Available Abstract Background Cattail (Typha domingensis has been spreading in phosphorus (P enriched areas of the oligotrophic Florida Everglades at the expense of sawgrass (Cladium mariscus spp. jamaicense. Abundant evidence in the literature explains how the opportunistic features of Typha might lead to a complete dominance in P-enriched areas. Less clear is how Typha can grow and acquire P at extremely low P levels, which prevail in the unimpacted areas of the Everglades. Results Apparent P uptake kinetics were measured for intact plants of Cladium and Typha acclimated to low and high P at two levels of oxygen in hydroponic culture. The saturated rate of P uptake was higher in Typha than in Cladium and higher in low-P acclimated plants than in high-P acclimated plants. The affinity for P uptake was two-fold higher in Typha than in Cladium, and two- to three-fold higher for low-P acclimated plants compared to high-P acclimated plants. As Cladium had a greater proportion of its biomass allocated to roots, the overall uptake capacity of the two species at high P did not differ. At low P availability, Typha increased biomass allocation to roots more than Cladium. Both species also adjusted their P uptake kinetics, but Typha more so than Cladium. The adjustment of the P uptake system and increased biomass allocation to roots resulted in a five-fold higher uptake per plant for Cladium and a ten-fold higher uptake for Typha. Conclusions Both Cladium and Typha adjust P uptake kinetics in relation to plant demand when P availability is high. When P concentrations are low, however, Typha adjusts P uptake kinetics and also increases allocation to roots more so than Cladium, thereby improving both efficiency and capacity of P uptake. Cladium has less need to adjust P uptake kinetics because it is already efficient at acquiring P from peat soils (e.g., through secretion of phosphatases, symbiosis with arbuscular mycorrhizal fungi, nutrient conservation growth

  9. Investigating differences across host species and scales to explain the distribution of the amphibian pathogen Batrachochytrium dendrobatidis.

    Directory of Open Access Journals (Sweden)

    Anna C Peterson

    Full Text Available Many pathogens infect more than one host species, and clarifying how these different hosts contribute to pathogen dynamics can facilitate the management of pathogens and can lend insight into the functioning of pathogens in ecosystems. In this study, we investigated a suite of native and non-native amphibian hosts of the pathogen Batrachochytrium dendrobatidis (Bd across multiple scales to identify potential mechanisms that may drive infection patterns in the Colorado study system. Specifically, we aimed to determine if: 1 amphibian populations vary in Bd infection across the landscape, 2 amphibian community composition predicts infection (e.g., does the presence or abundance of any particular species influence infection in others?, 3 amphibian species vary in their ability to produce infectious zoospores in a laboratory infection, 4 heterogeneity in host ability observed in the laboratory scales to predict patterns of Bd prevalence in the landscape. We found that non-native North American bullfrogs (Lithobates catesbeianus are widespread and have the highest prevalence of Bd infection relative to the other native species in the landscape. Additionally, infection in some native species appears to be related to the density of sympatric L. catesbeianus populations. At the smaller host scale, we found that L. catesbeianus produces more of the infective zoospore stage relative to some native species, but that this zoospore output does not scale to predict infection in sympatric wild populations of native species. Rather, landscape level infection relates most strongly to density of hosts at a wetland as well as abiotic factors. While non-native L. catesbeianus have high levels of Bd infection in the Colorado Front Range system, we also identified Bd infection in a number of native amphibian populations allopatric with L. catesbeianus, suggesting that multiple host species are important contributors to the dynamics of the Bd pathogen in this

  10. Seasonal and distributional patterns of seabirds along the Aleutian Archipelago

    Science.gov (United States)

    Renner, M.; Hunt, G.L.; Piatt, John F.; Byrd, G.V.

    2008-01-01

    The Aleutian Archipelago is of global importance to seabirds during the northern summer, but little is known about seabird use of these waters during winter. We compare summer and winter abundances of seabirds around 3 islands: Buldir in the western, Kasatochi in the central, and Aiktak in the eastern Aleutians. The density of combined seabird biomass in nearshore marine waters was higher in summer than in winter at Buldir and Kasatochi, but was higher in winter at Aiktak, despite the departure of abundant migratory species. Comparing foraging guilds, we found that only piscivores increased at the western and central sites in winter, whereas at the eastern site several planktivorous species increased as well. The only planktivore remaining in winter at the central and western sites in densities comparable to summer densities was whiskered auklet Aethia pygmaea. Crested auklet Aethia cristatella and thick-billed murre Uria lomvia showed the greatest proportional winter increase at the eastern site. The seasonal patterns of the seabird communities suggest a winter breakdown of the copepod-based food web in the central and western parts of the archipelago, and a system that remains rich in euphausiids in the eastern Aleutians. We suggest that in winter crested auklets take the trophic role that short-tailed shearwaters Puffinus tenuirostris occupy during summer. We hypothesize that advection of euphausiids in the Aleutian North Slope Current is important for supporting the high biomass of planktivores that occupy the Unimak Pass region on a year-round basis. ?? Inter-Research 2008.

  11. Distribution patterns of invasive alien species in Alabama, USA

    Directory of Open Access Journals (Sweden)

    Xiongwen Chen

    2012-12-01

    Full Text Available Invasive alien species (IAS cause environmental and economical problems. How to effectively manage all IAS at a large area is a challenge.Hypotheses about IAS (such as the “human activity” hypothesis, the “biotic acceptance” and the “biotic resistance” have been proposedfrom numerous studies. Here the state of Alabama in USA, widely occupied by IAS, is used as a case study for characterizing the emergentpatterns of IAS. The results indicate that most IAS are located in metropolitan areas and in the Black Belt area which is a historical intensiveland use area. There are positive relationships between the richness of IAS and the change of human population, the species richness and thenumber of endangered species, as well as the total road length and farmland area across Alabama. This study partially supports the abovethree hypotheses and provides a general pattern of local IAS. Based on possible processes related with IAS, some implications forstrategically managing local IAS are discussed.

  12. Tree species exhibit complex patterns of distribution in bottomland hardwood forests

    Science.gov (United States)

    Luben D Dimov; Jim L Chambers; Brian R. Lockhart

    2013-01-01

    & Context Understanding tree interactions requires an insight into their spatial distribution. & Aims We looked for presence and extent of tree intraspecific spatial point pattern (random, aggregated, or overdispersed) and interspecific spatial point pattern (independent, aggregated, or segregated). & Methods We established twelve 0.64-ha plots in natural...

  13. A Study of Thumb Print Patterns and ABO Blood Group Distribution ...

    African Journals Online (AJOL)

    The aim of this study was to establish a possible relationship between thumb print pattern and ABO blood group distribution. The study involves two hundred and nine-two volunteers comprising 159 female and 133 male. The blood group and finger print patterns were determined using standard techniques. Results ...

  14. The distribution pattern of Hirneola auricula-judae in the Netherlands

    NARCIS (Netherlands)

    Laan, van der H.F.

    1976-01-01

    The distribution pattern of Hirneola auricula-judae in the Netherlands is discussed. At first this pattern was thought to be mainly determined by the average daily minimum temperatures in winter; high population densities correlating with high winter temperatures. The curve which best fits the data

  15. [Relations between reward-distribution patterns and distribution strategies: how five-year-old children distribute rewards].

    Science.gov (United States)

    Tsutsu, Kiyomi

    2013-08-01

    The relationship between children's reward-distribution judgments and their distribution strategies was investigated. Five-year-old children (N = 61) were presented with two stories where two characters made different numbers of origami stars. The children were asked to distribute different numbers of rewards to the characters: equal to (Middle-N), less than (Small-N), or more than (Large-N) the total number of stars in each story. Distribution strategies were categorized into two types: One-round, where rewards were distributed in one round only, and Cyclic, where the rewards were distributed in several cycles across the characters. In the Small-N of both stories (4 or 8 rewards), most children distributed rewards equally. When the number of rewards was 4, more than half used the One-round strategy, but when it was 8, more than half used the Cyclic strategy. In the Middle-N and Large-N conditions, most equal distributions used the Cyclic strategy, whereas almost all the proportional-equity distributions were associated with the One-round strategy, and most ordinal-equity distributions used the Cyclic strategy. The relationships between automatic/controlled reward-distribution judgments and distribution strategies were discussed.

  16. Tardigrades of Alaska: distribution patterns, diversity and species richness

    Directory of Open Access Journals (Sweden)

    Carl Johansson

    2013-05-01

    Full Text Available During the summer of 2010, a biotic survey of tardigrades was conducted along a latitudinal transect in central Alaska from the Kenai Peninsula, via Fairbanks and the Arctic Circle to the coastal plain. Work was centred at the Toolik and Bonanza Creek Long Term Ecological Research Network sites and supplemented by opportunistic collections from the Kenai Peninsula and Anchorage areas. The 235 samples collected at 20 sites over 10 degrees of latitude yielded 1463 tardigrades representing two classes, three orders, 10 families, 23 genera and 73 species from 142 positive samples. A total of 50 species are new to Alaska, increasing the state's known species richness to 84. Several environmental metrics, such as pH, substrate, elevation, location and habitat were measured, recorded and analysed along the latitudinal gradient. Contrary to expectations, pH did not appear to be a predictor of tardigrade abundance or distribution. Density and species richness were relatively consistent across sites. However, the assemblages were highly variable within and between sites at only 14–20% similarity. We detected no correlation between species diversity and latitudinal or environmental gradients, though this may be affected by a high (59.9% occurrence of single-species samples (containing individuals of only one species. Estimates of species richness were calculated for Alaska (118 and the Arctic (172. Our efforts increased the number of known species in Alaska to 84, and those results led us to question the validity of the estimate numbers.

  17. Distributed dynamical computation in neural circuits with propagating coherent activity patterns.

    Directory of Open Access Journals (Sweden)

    Pulin Gong

    2009-12-01

    Full Text Available Activity in neural circuits is spatiotemporally organized. Its spatial organization consists of multiple, localized coherent patterns, or patchy clusters. These patterns propagate across the circuits over time. This type of collective behavior has ubiquitously been observed, both in spontaneous activity and evoked responses; its function, however, has remained unclear. We construct a spatially extended, spiking neural circuit that generates emergent spatiotemporal activity patterns, thereby capturing some of the complexities of the patterns observed empirically. We elucidate what kind of fundamental function these patterns can serve by showing how they process information. As self-sustained objects, localized coherent patterns can signal information by propagating across the neural circuit. Computational operations occur when these emergent patterns interact, or collide with each other. The ongoing behaviors of these patterns naturally embody both distributed, parallel computation and cascaded logical operations. Such distributed computations enable the system to work in an inherently flexible and efficient way. Our work leads us to propose that propagating coherent activity patterns are the underlying primitives with which neural circuits carry out distributed dynamical computation.

  18. Spatial patterns of primary productivity derived from the Dynamic Habitat Indices predict patterns of species richness and distributions in the tropics

    Science.gov (United States)

    Suttidate, Naparat

    Humans are changing the Earth's ecosystems, which has profound consequences for biodiversity. To understand how species respond to these changes, biodiversity science requires accurate assessments of biodiversity. However, biodiversity assessments are still limited in tropical regions. The Dynamic Habitat Indices (DHIs), derived from satellite data, summarize dynamic patterns of annual primary productivity: (a) cumulative annual productivity, (b) minimum annual productivity, and (c) seasonal variation in productivity. The DHIs have been successfully used in temperate regions, but not yet in the tropics. My goal was to evaluate the importance of primary productivity measured via the DHIs for assessing patterns of species richness and distributions in Thailand. First, I assessed the relationships between the DHIs and tropical bird species richness. I also evaluated the complementarity of the DHIs and topography, climate, latitudinal gradients, habitat heterogeneity, and habitat area in explaining bird species richness. I found that among three DHIs, cumulative annual productivity was the most important factor in explaining bird species richness and that the DHIs outperformed other environmental variables. Second, I developed texture measures derive from DHI cumulative annual productivity, and compared them to habitat composition and fragmentation as predictors of tropical forest bird distributions. I found that adding texture measures to habitat composition and fragmentation models improved the prediction of tropical bird distributions, especially area- and edge-sensitive tropical forest bird species. Third, I predicted the effects of trophic interactions between primary productivity, prey, and predators in relation to habitat connectivity for Indochinese tigers (Panthera tigris). I found that including trophic interactions improved habitat suitability models for tigers. However, tiger habitat is highly fragmented with few dispersal corridors. I also identified

  19. Interactions between aggregations and environmental factors explain spatio-temporal patterns of the brittle-star Ophiothrix fragilis in the eastern Bay of Seine

    Science.gov (United States)

    Dauvin, Jean-Claude; Méar, Yann; Murat, Anne; Poizot, Emmanuel; Lozach, Sophie; Beryouni, Khadija

    2013-10-01

    There is a paucity of studies showing long-term changes in the population dynamics of dominant benthic epifaunal species, especially echinoderms, in relation to biological and environmental factors. In the English Channel, the brittle-star Ophiothrix fragilis is a common epifaunal species, mainly found in strong tidal currents characterised by benthic habitats with pebbles. However, in the Bay of Seine, O. fragilis lives on gravel and coarse sandy sediments; more locally, it occurs where there are unexpected amounts of fine particles for such high hydrodynamic areas. This species forms dense aggregations, supporting large populations up to 7450 ind m-2. This paper analyses the long-term spatio-temporal changes of O. fragilis aggregations over the last 25 years in the eastern part of the Bay of Seine through observations obtained from several scientific programmes from 1986 to 2010. This area is characterised as a tidal environment affected by the Seine estuary and is subject to potential sediment supply from the dumping site of the Le Havre harbour dredging operations. During all surveys, there was a similar pattern: persistent patches with high abundances of O. fragilis and sites without O. fragilis, showing that there was a high heterogeneity of the spatial population pattern. Interactions between environmental conditions and ophiurid aggregations (e.g., storm waves, Seine floods and patches) are suggested to explain these patterns.

  20. Mid-tertiary dispersal, not Gondwanan vicariance explains distribution patterns in the wax palm subfamily (Ceroxyloideae: Arecaceae)

    DEFF Research Database (Denmark)

    Trénel, Philipp; Gustafsson, Mats; Baker, W.J.

    2007-01-01

    The Ceroxyloideae is a small but heterogeneous subfamily of palms (Arecaceae, Palmae). It includes a Caribbean lineage (tribe Cyclospathae), a southern hemisphere disjunction (tribe Ceroxyleae), and an amphi-Andean element (tribe Phytelepheae), until recently considered a distinct subfamily (Phyt...... proposed. Radiation in this tribe coincides largely with the major uplift of the Andes, favoring Andean orogeny over Pleistocene climatic changes as a possible speciation-promoting factor in this tribe........ Austral interplate dispersal of Oraniopsis to Australia could have occurred, but apparently only in the mid-Eocene/early Oligocene interval after global cooling had begun. Our data do not support Pleistocene climatic changes as drivers for speciation in the Andean-centered Phytelepheae as previously...

  1. Diffraction patterns from holographic masks generated using combined axicon and helical phase distributions

    Science.gov (United States)

    Mihailescu, M.; Preda, L.; Kusko, C.; Scarlat, E. I.

    2015-02-01

    The diffraction patterns (DPs) from helical phase distributions were intensively studied due to their peculiar capability of carrying orbital angular momentum. In the present study, we investigated the combination between a helical phase distribution and another distribution: axicon in our case. Such phase distributions were digitally embedded into holographic masks (HMs). The reconstruction step is performed by simulating the propagation through these HMs, using scalar diffraction theory, Fraunhofer approximation. The spatial intensity arrangement of the DPs is investigated linked with the radial and azimuthal constructive parameters values of the diffractive phase structures embedded in the HMs and transferred in these DPs. Keywords: helical phase distribution

  2. Patterns of distribution of childhood cancer in Africa.

    Science.gov (United States)

    Stefan, D Cristina

    2015-06-01

    Very little is known about the regional variation in the incidence of childhood malignancies in Africa. The aim of the study was to perform a comprehensive analysis of the distribution of childhood cancer in Sub-Saharan Africa and compare the results to the Globocan estimations. A letter of invitation to participate was sent to all registry centers in Africa registered with the International Agency for Research on Cancer and to all African centers registered with AORTIC and SIOP Africa, requesting similar information as in CanReg 4. Childhood cancers were defined as those occurring below the age of 15 years. The data requested was from 2000 to 2010. The malignancies were classified and coded according to the International Classification of Childhood Cancer, 2004 system. Data obtained were analyzed using EpiInfo and Statistica 10 software. Information regarding the estimation of the numbers and incidence of the top 5 childhood cancers in specific countries was obtained from Globocan Web site. There were 21 centers included in the study from 18 Sub-Saharan African countries. The data analyzed differed from center to center and included cases from 1985 to 2011. The proportion of childhood cancer out of all cancers ranged between 1.4% in Ghana to 10.0% in Rwanda. In Southern Africa, Kaposi sarcoma was the most common malignancy in children in Mozambique (15.8% of all cases) and the second most common in Zambia (15.6%) and in Malawi (12.4%). In Eastern Africa, Uganda recorded Kaposi sarcoma as the most common tumor in children (22.0%), while two Kenyan centers reported mainly Burkitt lymphoma (25.1 and 37.1%, respectively). In Central Africa, Congo classified retinoblastoma as the most common childhood cancer with an incidence of 20.1%. In Western Africa, Non-Hodgkin lymphoma was the most common in Ghana (53.6%), in Ivory Coast (73.6%) and in Mali (32.7%). Nephroblastoma remains the most common solid tumor in Africa exceeding 10% of total pediatric cancers in many

  3. An impaired metabolic response to hydrostatic pressure explains Alcanivorax borkumensis recorded distribution in the deep marine water column

    KAUST Repository

    Scoma, Alberto

    2016-08-12

    Alcanivorax borkumensis is an ubiquitous model organism for hydrocarbonoclastic bacteria, which dominates polluted surface waters. Its negligible presence in oil-contaminated deep waters (as observed during the Deepwater Horizon accident) raises the hypothesis that it may lack adaptive mechanisms to hydrostatic pressure (HP). The type strain SK2 was tested under 0.1, 5 and 10 MPa (corresponding to surface water, 500 and 1000 m depth, respectively). While 5 MPa essentially inactivated SK2, further increase to 10 MPa triggered some resistance mechanism, as indicated by higher total and intact cell numbers. Under 10 MPa, SK2 upregulated the synthetic pathway of the osmolyte ectoine, whose concentration increased from 0.45 to 4.71 fmoles cell-1. Central biosynthetic pathways such as cell replication, glyoxylate and Krebs cycles, amino acids metabolism and fatty acids biosynthesis, but not β-oxidation, were upregulated or unaffected at 10 MPa, although total cell number was remarkably lower with respect to 0.1 MPa. Concomitantly, expression of more than 50% of SK2 genes was downregulated, including genes related to ATP generation, respiration and protein translation. Thus, A. borkumensis lacks proper adaptation to HP but activates resistance mechanisms. These consist in poorly efficient biosynthetic rather than energy-yielding degradation-related pathways, and suggest that HP does represent a major driver for its distribution at deep-sea.

  4. Complexity explained

    CERN Document Server

    Erdi, Peter

    2008-01-01

    This book explains why complex systems research is important in understanding the structure, function and dynamics of complex natural and social phenomena. Readers will learn the basic concepts and methods of complex system research.

  5. Human papillomavirus distribution in invasive cervical carcinoma in sub-Saharan Africa: could HIV explain the differences?

    Science.gov (United States)

    Ndiaye, Cathy; Alemany, Laia; Ndiaye, Nafissatou; Kamaté, Bakarou; Diop, Yankhoba; Odida, Michael; Banjo, Kunbi; Tous, Sara; Klaustermeier, Jo Ellen; Clavero, Omar; Castellsagué, Xavier; Bosch, F Xavier; Trottier, Helen; de Sanjosé, Silvia

    2012-12-01

    To describe human papillomavirus (HPV) distribution in invasive cervical carcinoma (ICC) from Mali and Senegal and to compare type-specific relative contribution among sub-Saharan African (SSA) countries. A multicentric study was conducted to collect paraffin-embedded blocks of ICC. Polymerase chain reaction, DNA enzyme immunoassay and line probe assay were performed for HPV detection and genotyping. Data from SSA (Mozambique, Nigeria and Uganda) and 35 other countries were compared. One hundred and sixty-four ICC cases from Mali and Senegal were tested from which 138 were positive (adjusted prevalence = 86.8%; 95% CI = 79.7-91.7%). HPV16 and HPV18 accounted for 57.2% of infections and HPV45 for 16.7%. In SSA countries, HPV16 was less frequent than in the rest of the world (49.4%vs. 62.6%; P < 0.0001) but HPV18 and HPV45 were two times more frequent (19.3%vs. 9.4%; P < 0.0001 and 10.3%vs. 5.6%; P < 0.0001, respectively). There was an ecological correlation between HIV prevalence and the increase of HPV18 and the decrease of HPV45 in ICC in SSA (P = 0.037 for both). HPV16/18/45 accounted for two-thirds of the HPV types found in invasive cervical cancer in Mali and Senegal. Our results suggest that HIV may play a role in the underlying HPV18 and HPV45 contribution to cervical cancer, but further studies are needed to confirm this correlation. © 2012 Blackwell Publishing Ltd.

  6. Pre-Quaternary divergence and subsequent radiation explain longitudinal patterns of genetic and morphological variation in the striped skink, Heremites vittatus.

    Science.gov (United States)

    Baier, Felix; Schmitz, Andreas; Sauer-Gürth, Hedwig; Wink, Michael

    2017-06-09

    Many animal and plant species in the Middle East and northern Africa have a predominantly longitudinal distribution, extending from Iran and Turkey along the eastern Mediterranean coast into northern Africa. These species are potentially characterized by longitudinal patterns of biological diversity, but little is known about the underlying biogeographic mechanisms and evolutionary timescales. We examined these questions in the striped skink, Heremites vittatus, one such species with a roughly longitudinal distribution across the Middle East and northern Africa, by analyzing range-wide patterns of mitochondrial DNA (mtDNA) sequence and multi-trait morphological variation. The striped skink exhibits a basic longitudinal organization of mtDNA diversity, with three major mitochondrial lineages inhabiting northern Africa, the eastern Mediterranean coast, and Turkey/Iran. Remarkably, these lineages are of pre-Quaternary origin, and are characterized by p-distances of 9-10%. In addition, within each of these lineages a more recent Quaternary genetic diversification was observed, as evidenced by deep subclades and high haplotype diversity especially in the Turkish/Iranian and eastern Mediterranean lineages. Consistent with the genetic variation, our morphological analysis revealed that the majority of morphological traits show significant mean differences between specimens from northern Africa, the eastern Mediterranean coast, and Turkey/Iran, suggesting lineage-specific trait evolution. In addition, a subset of traits exhibits clinal variation along the eastern Mediterranean coast, potentially indicating selection gradients at the geographic transition from northern Africa to Anatolia. The existence of allopatric, morphologically and genetically divergent lineages suggests that Heremites vittatus might represent a complex with several taxa. Our work demonstrates that early divergence events in the Pliocene, likely driven by both climatic and geological factors

  7. The Analysis of Tree Species Distribution Information Extraction and Landscape Pattern Based on Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Yi Zeng

    2017-08-01

    Full Text Available The forest ecosystem is the largest land vegetation type, which plays the role of unreplacement with its unique value. And in the landscape scale, the research on forest landscape pattern has become the current hot spot, wherein the study of forest canopy structure is very important. They determines the process and the strength of forests energy flow, which influences the adjustments of ecosystem for climate and species diversity to some extent. The extraction of influencing factors of canopy structure and the analysis of the vegetation distribution pattern are especially important. To solve the problems, remote sensing technology, which is superior to other technical means because of its fine timeliness and large-scale monitoring, is applied to the study. Taking Lingkong Mountain as the study area, the paper uses the remote sensing image to analyze the forest distribution pattern and obtains the spatial characteristics of canopy structure distribution, and DEM data are as the basic data to extract the influencing factors of canopy structure. In this paper, pattern of trees distribution is further analyzed by using terrain parameters, spatial analysis tools and surface processes quantitative simulation. The Hydrological Analysis tool is used to build distributed hydrological model, and corresponding algorithm is applied to determine surface water flow path, rivers network and basin boundary. Results show that forest vegetation distribution of dominant tree species present plaque on the landscape scale and their distribution have spatial heterogeneity which is related to terrain factors closely. After the overlay analysis of aspect, slope and forest distribution pattern respectively, the most suitable area for stand growth and the better living condition are obtained.

  8. Spatial pattern of 2009 dengue distribution in Kuala Lumpur using GIS application.

    Science.gov (United States)

    Aziz, S; Ngui, R; Lim, Y A L; Sholehah, I; Nur Farhana, J; Azizan, A S; Wan Yusoff, W S

    2012-03-01

    In the last few years in Malaysia, dengue fever has increased dramatically and has caused huge public health concerns. The present study aimed to establish a spatial distribution of dengue cases in the city of Kuala Lumpur using a combination of Geographic Information System (GIS) and spatial statistical tools. Collation of data from 1,618 dengue cases in 2009 was obtained from Kuala Lumpur City Hall (DBKL). These data were processed and then converted into GIS format. Information on the average monthly rainfall was also used to correlate with the distribution pattern of dengue cases. To asses the spatial distribution of dengue cases, Average Nearest Neighbor (ANN) Analysis was applied together with spatial analysis with the ESRI ArcGIS V9.3 programme. Results indicated that the distribution of dengue cases in Kuala Lumpur for the year 2009 was spatially clustered with R value less than 1 (R = 0.42; z-scores = - 4.47; p 1) between August and November. In addition, the mean monthly rainfall has not influenced the distribution pattern of the dengue cases. Implementation of control measures is more difficult for dispersed pattern compared to clustered pattern. From this study, it was found that distribution pattern of dengue cases in Kuala Lumpur in 2009 was spatially distributed (dispersed or clustered) rather than cases occurring randomly. It was proven that by using GIS and spatial statistic tools, we can determine the spatial distribution between dengue and population. Utilization of GIS tools is vital in assisting health agencies, epidemiologist, public health officer, town planner and relevant authorities in developing efficient control measures and contingency programmes to effectively combat dengue fever.

  9. Invertebrate distribution patterns and river typology for the implementation of the water framework directive in Martinique, French Lesser Antilles

    Directory of Open Access Journals (Sweden)

    Bernadet C.

    2013-03-01

    Full Text Available Over the past decade, Europe’s Water Framework Directive provided compelling reasons for developing tools for the biological assessment of freshwater ecosystem health in member States. Yet, the lack of published study for Europe’s overseas regions reflects minimal knowledge of the distribution patterns of aquatic species in Community’s outermost areas. Benthic invertebrates (84 taxa and land-cover, physical habitat and water chemistry descriptors (26 variables were recorded at fifty-one stations in Martinique, French Lesser Antilles. Canonical Correspondence Analysis and Ward’s algorithm were used to bring out patterns in community structure in relation to environmental conditions, and variation partitioning was used to specify the influence of geomorphology and anthropogenic disturbance on invertebrate communities. Species richness decreased from headwater to lowland streams, and species composition changed from northern to southern areas. The proportion of variation explained by geomorphological variables was globally higher than that explained by anthropogenic variables. Geomorphology and land cover played key roles in delineating ecological sub-regions for the freshwater biota. Despite this and the small surface area of Martinique (1080 km2, invertebrate communities showed a clear spatial turnover in composition and biological traits (e.g., insects, crustaceans and molluscs in relation to natural conditions.

  10. Formal Verification of Architectural Patterns in Support of Dependable Distributed Systems

    Science.gov (United States)

    2005-07-01

    JUL 2005 2. REPORT TYPE 3. DATES COVERED 00-00-2005 to 00-00-2005 4. TITLE AND SUBTITLE Extended Abstract: Formal Verification of Architectural...Rev. 8-98) Prescribed by ANSI Std Z39-18 Extended Abstract: Formal Verification of Architectural Patterns in Support of Dependable Distributed...itd.nrl.navy.mil Keywords: Architectural patterns, dependable software, component-based development, formal verification . 1. Introduction Building

  11. The intestinal distribution pattern of appetite- and glucose regulatory peptides in mice, rats and pigs

    DEFF Research Database (Denmark)

    Albrechtsen, Nicolai Jacob Wewer; Kuhre, Rune Ehrenreich; Toräng, Signe

    2016-01-01

    in mice (n = 9), rats (n = 9) and pigs (n = 8), using validated radioimmunoassays. RESULTS: GLP-1, GLP-2 and oxyntomodulin/glicentin show similar patterns of distribution within the respective species, but for rats and pigs the highest levels were found in the distal small intestine, whereas for the mouse...... in all three species. Most surprisingly, in the pig PYY was found in large amounts in the proximal part of the small intestine whereas both rats and mice had undetectable levels until the distal small intestine. CONCLUSIONS: In summary, the distribution patterns of extractable GIP, GLP-1, GLP-2...

  12. The numerical model of the sediment distribution pattern at Lampulo National fisheries port

    Science.gov (United States)

    Irham, M.; Setiawan, I.

    2018-01-01

    The spatial distribution of sediment pattern was studied at Lampulo Fisheries Port, Krueng Aceh estuarial area, Banda Aceh. The research was conducted using the numerical model of wave-induced currents at shallow water area. The study aims to understand how waves and currents react to the pattern of sediment distribution around the beach structure in that region. The study demonstrated that the port pool area had no sedimentation and erosion occurred because the port was protected by the jetty as the breakwater to defend the incoming waves toward the pool. The protected pool created a weak current circulation to distribute the sediments. On the other hand, the sediments were heavily distributed along the beach due to the existence of longshore currents near the shoreline (outside the port pool area). Meanwhile, at the estuarial area, the incoming fresh water flow responded to the coastal shallow water currents, generating Eddy-like flow at the mouth of the river.

  13. Sediment-hosted contaminants and distribution patterns in the Mississippi and Atchafalaya River Deltas

    Science.gov (United States)

    Flocks, James G.; Kindinger, Jack G.; Ferina, Nicholas; Dreher, Chandra

    2002-01-01

    The Mississippi and Atchafalaya Rivers transport very large amounts of bedload and suspended sediments to the deltaic and coastal environments of the northern Gulf of Mexico. Absorbed onto these sediments are contaminants that may be detrimental to the environment. To adequately assess the impact of these contaminants it is first necessary to develop an understanding of sediment distribution patterns in these deltaic systems. The distribution patterns are defined by deltaic progradational cycles. Once these patterns are identified, the natural and industrial contaminant inventories and their depositional histories can be reconstructed. Delta progradation is a function of sediment discharge, as well as channel and receiving-basin dimensions. Fluvial energy controls the sediment distribution pattern, resulting in a coarse grained or sandy framework, infilled with finer grained material occupying the overbank, interdistributary bays, wetlands and abandoned channels. It has been shown that these fine-grained sediments can carry contaminants through absorption and intern them in the sediment column or redistribute them depending on progradation or degradation of the delta deposit. Sediment distribution patterns in delta complexes can be determined through high-resolution geophysical surveys and groundtruthed with direct sampling. In the Atchafalaya and Mississippi deltas, remote sensing using High-Resolution Single-Channel Seismic Profiling (HRSP) and Sidescan Sonar was correlated to 20-ft vibracores to develop a near-surface geologic framework that identifies variability in recent sediment distribution patterns. The surveys identified bedload sand waves, abandoned-channel back-fill, prodelta and distributary mouth bars within the most recently active portions of the deltas. These depositional features respond to changes in deltaic processes and through their response may intern or transport absorbed contaminants. Characterizing these features provides insight into the

  14. Centrifugal spreader mass and nutrients distribution patterns for application of fresh and aged poultry litter.

    Science.gov (United States)

    Temple, W D; Skowrońska, M; Bomke, A A

    2014-06-15

    A spin-type centrifugal spreader was evaluated using fresh and aged poultry litter upon dry mass, product nitrogen (N), phosphorus (P) and potassium (K), incubation study soil available N and particle size distribution patterns. Relative to the aged litter (37% moisture content), the fresh litter (17% moisture content) had greater litter, the broadcast fresh litter resulted in higher coefficients of variation (CV) over its transverse distance, a narrower calculated space distance between passes for uniform spread and lower soil available N concentrations. For nitrogen application over the broadcast transverse distance the fresh litter displayed a high R(2) best fit 4th order polynomial distribution pattern, while the aged litter showed high R(2) best fit 6th order polynomial distribution pattern. A soil incubation study of the fresh and aged broadcast litter resulted in a more variable or lower R(2) best fit 2nd order polynomial distribution pattern. For both the fresh and aged litter, the calculated distance between passes to achieve a uniform mass distribution was greater than that required for the broadcast of soil available N. For the fresh litter, the soil available N and litter P concentration levels strongly correlated (relatively high p and R(2) values) with the litter this relationship was not as significant. In addition to reducing the health risk (i.e. pathogens, antibiotic residues and resistant bacteria) and/or environment issues (particulate fallout onto waterways, adjacent fields and/or residences) our study mass, particulate and N distribution patterns results suggest that poultry litter should be allowed to age before broadcast application is attempted. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. The human cerebral cortex is neither one nor many: neuronal distribution reveals two quantitatively different zones in the gray matter, three in the white matter, and explains local variations in cortical folding

    Science.gov (United States)

    Ribeiro, Pedro F. M.; Ventura-Antunes, Lissa; Gabi, Mariana; Mota, Bruno; Grinberg, Lea T.; Farfel, José M.; Ferretti-Rebustini, Renata E. L.; Leite, Renata E. P.; Filho, Wilson J.; Herculano-Houzel, Suzana

    2013-01-01

    The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex) the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital) that differ in how neurons are distributed across their gray matter volume and in three zones (prefrontal, occipital, and non-occipital) that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non-occipital areas. PMID

  16. The human cerebral cortex is neither one nor many: Neuronal distribution reveals two quantitatively different zones in the grey matter, three in the white matter, and explains local variations in cortical folding

    Directory of Open Access Journals (Sweden)

    Pedro F. M. Ribeiro

    2013-09-01

    Full Text Available The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital that differ in how neurons distributed across their grey matter volume and in three zones (prefrontal, occipital, and non-occipital that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non

  17. Distribution patterns of shallow water polychaetes (Annelida along the Alexandria coast, Egypt (eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    M. M. DORGHAM

    2014-10-01

    Full Text Available Shallow hard bottom and intertidal soft bottom polychaete assemblages of the Alexandria coast, southeastern Mediterranean (Levantine Sea, were studied during a complete annual cycle in order to analyze spatial temporal patterns of variation in assemblages, and relevant factors related to polychaete distribution. The present study recorded a total of 73 species, belonging to Syllidae (22 species, Nereididae (9 species, Serpulidae (6 species, Eunicidae (5 species and other 19 families. The assemblages experienced pronounced spatial and temporal variation throughout the study area, but spatial variation appeared more important in determining the observed patterns. Polychaete distribution related to variation of grain size and sessile macrobenthos cover suggesting that these structural variables accounted more than the physical-chemical ones (namely BOD, dissolved oxygen, organic carbon, organic matter, salinity, temperature, pH in influencing the patterns of assemblages’ distribution. The present study is the southeastern-most one dealing with ecology and distribution patterns of hard bottom polychaetes from the Mediterranean Sea, as well as one of the few studies dealing with intertidal soft bottom polychaetes in the Levant Basin.

  18. Distribution pattern assessment of a dual-purpose disc agrochemical applicator for field crops

    Directory of Open Access Journals (Sweden)

    M. S. Abubakar

    2012-08-01

    Full Text Available A dual-purpose disc agrochemical applicator for field crops was developed to boost agricultural mechanization in crop production and also to overcome the safety concern of hazardous spray drift during agrochemical application by the field crop farmers. The dual purpose agrochemical applicator was mounted on a high clearance tractor and tested with respect to the granular fertilizer distribution patterns uniformity/liquid chemical uniformity of droplet sizes in spraying of the agrochemical. Results for NPK granular chemical indicated that, at low (50 kg/ha and high (150 kg/ha application rates with 550 rpm disc speed, distribution patterns skewed to the left whereas the distribution pattern at medium (100 kg/ha application rates was good flattop. Also at high application rate with 1000 rpm disc speed, mean distribution pattern became poor (W-shape. For the liquid chemical herbicide HC 48 amine liquid, the mean values of volume median diameter (VMD and number median diameter (NMD were 108 µm and 80 µm at 90 lt/ha application rate at 5000 rpm rotary disc speed, and also 344 and 222 µm at 30 lt/ha application rate with 2000 rpm rotary disc speed. The mean values of coefficient of uniformity for droplet sizes expressed as VMD/NMD found in this study were in the range of 1.35 to 1.55 for HC amine 48 liquid chemical.

  19. An Algorithm to Compute the Character Access Count Distribution for Pattern Matching Algorithms

    NARCIS (Netherlands)

    T. Marschall (Tobias); S. Rahmann (Sven)

    2011-01-01

    textabstractWe propose a framework for the exact probabilistic analysis of window-based pattern matching algorithms, such as Boyer--Moore, Horspool, Backward DAWG Matching, Backward Oracle Matching, and more. In particular, we develop an algorithm that efficiently computes the distribution of a

  20. Distribution patterns of medicinal plants along an elevational gradient in central Himalaya, Nepal

    Czech Academy of Sciences Publication Activity Database

    Rokaya, Maan Bahadur; Münzbergová, Zuzana; Shrestha, M.R.; Timsina, B.

    2012-01-01

    Roč. 9, č. 2 (2012), s. 201-213 ISSN 1672-6316 R&D Projects: GA ČR GA526/09/0549 Institutional research plan: CEZ:AV0Z60050516 Keywords : distribution patterns * medicinal plants * unimodal relationships Subject RIV: EF - Botanics Impact factor: 0.664, year: 2012

  1. Pattern and spatial distribution of plague in Lushoto, north-eastern ...

    African Journals Online (AJOL)

    A review of plague records from 1986 to 2002 and household interviews were carried out in the plague endemic villages to establish a pattern and spatial distribution of the disease in Lushoto district, Tanzania. Spatial data of households and village centres were collected and mapped using a hand held Global Positioning ...

  2. Distribution patterns of terrestrial mammals in KwaZulu-Natal | Rowe ...

    African Journals Online (AJOL)

    Distribution patterns, plotted by eighth-degree squares (7.5' x 7.5'), of the 162 mammal species recorded in the province of KwaZulu-Natal, South Africa were examined in relation to the combined factors of vegetation type, climate, and altitude (= bioregions); and in relation to protected areas within the nine bioregions.

  3. Pattern of hair distribution on the dorsal phalanges of the hand in ...

    African Journals Online (AJOL)

    Background: The distribution of hair in the dorsal aspect of the hand digits were investigated in this study. Aim: To determine dorsal phalengeal hair pattern in an African ethnic group. Methods: The study involved 160 male and 140 female of Urhobo volunteers whose ages ranged between 18 and 38 years. Results: Hair ...

  4. SPSS explained

    CERN Document Server

    Hinton, Perry R; Brownlow, Charlotte

    2014-01-01

    SPSS Explained provides the student with all that they need to undertake statistical analysis using SPSS. It combines a step-by-step approach to each procedure with easy to follow screenshots at each stage of the process. A number of other helpful features are provided: regular advice boxes with tips specific to each test explanations divided into 'essential' and 'advanced' sections to suit readers at different levels frequently asked questions at the end of each chapter. The first edition of this popular book has been fully updated for IBM SPSS version 21 and also includes: chapters that expl

  5. Social-ecological drivers of multiple ecosystem services: what variables explain patterns of ecosystem services across the Norrström drainage basin?

    Directory of Open Access Journals (Sweden)

    Megan Meacham

    2016-03-01

    Full Text Available In human dominated landscapes many diverse, and often antagonistic, human activities are intentionally and inadvertently determining the supply of various ecosystem services. Understanding how different social and ecological factors shape the availability of ecosystem services is essential for fair and effective policy and management. In this paper, we evaluate how well alternative social-ecological models of human impact on ecosystems explain patterns of 16 ecosystem services (ES across the 62 municipalities of the Norrström drainage basin in Sweden. We test four models of human impact on ecosystems, land use, ecological modernization, ecological footprint, and location theory, and test their ability to predict both individual ES and bundles of ES. We find that different models do best to predict different types of individual ES. Land use is the best model for predicting provisioning services, standing water quality, biodiversity appreciation, and cross-country skiing, while other models work better for the remaining services. However, this range of models is not able to predict some of the cultural ES. ES bundles are predicted worse than individual ES by these models, but provide a clear picture of variation in multiple ecosystem services based on limited information. Based on our results, we offer suggestions on how social-ecological modeling and assessments of ecosystems can be further developed.

  6. Does the Arcto-Tertiary biogeographic hypothesis explain the disjunct distribution of Northern Hemisphere herbaceous plants? The case of Meehania (Lamiaceae).

    Science.gov (United States)

    Deng, Tao; Nie, Ze-Long; Drew, Bryan T; Volis, Sergei; Kim, Changkyun; Xiang, Chun-Lei; Zhang, Jian-Wen; Wang, Yue-Hua; Sun, Hang

    2015-01-01

    Despite considerable progress, many details regarding the evolution of the Arcto-Tertiary flora, including the timing, direction, and relative importance of migration routes in the evolution of woody and herbaceous taxa of the Northern Hemisphere, remain poorly understood. Meehania (Lamiaceae) comprises seven species and five subspecies of annual or perennial herbs, and is one of the few Lamiaceae genera known to have an exclusively disjunct distribution between eastern Asia and eastern North America. We analyzed the phylogeny and biogeographical history of Meehania to explore how the Arcto-Tertiary biogeographic hypothesis and two possible migration routes explain the disjunct distribution of Northern Hemisphere herbaceous plants. Parsimony and Bayesian inference were used for phylogenetic analyses based on five plastid sequences (rbcL, rps16, rpl32-trnH, psbA-trnH, and trnL-F) and two nuclear (ITS and ETS) gene regions. Divergence times and biogeographic inferences were performed using Bayesian methods as implemented in BEAST and S-DIVA, respectively. Analyses including 11 of the 12 known Meehania taxa revealed incongruence between the chloroplast and nuclear trees, particularly in the positions of Glechoma and Meehania cordata, possibly indicating allopolyploidy with chloroplast capture in the late Miocene. Based on nrDNA, Meehania is monophyletic, and the North American species M. cordata is sister to a clade containing the eastern Asian species. The divergence time between the North American M. cordata and the eastern Asian species occurred about 9.81 Mya according to the Bayesian relaxed clock methods applied to the combined nuclear data. Biogeographic analyses suggest a primary role of the Arcto-Tertiary flora in the study taxa distribution, with a northeast Asian origin of Meehania. Our results suggest an Arcto-Tertiary origin of Meehania, with its present distribution most probably being a result of vicariance and southward migrations of populations during

  7. Spatial Distribution Characteristics of Healthcare Facilities in Nanjing: Network Point Pattern Analysis and Correlation Analysis.

    Science.gov (United States)

    Ni, Jianhua; Qian, Tianlu; Xi, Changbai; Rui, Yikang; Wang, Jiechen

    2016-08-18

    The spatial distribution of urban service facilities is largely constrained by the road network. In this study, network point pattern analysis and correlation analysis were used to analyze the relationship between road network and healthcare facility distribution. The weighted network kernel density estimation method proposed in this study identifies significant differences between the outside and inside areas of the Ming city wall. The results of network K-function analysis show that private hospitals are more evenly distributed than public hospitals, and pharmacy stores tend to cluster around hospitals along the road network. After computing the correlation analysis between different categorized hospitals and street centrality, we find that the distribution of these hospitals correlates highly with the street centralities, and that the correlations are higher with private and small hospitals than with public and large hospitals. The comprehensive analysis results could help examine the reasonability of existing urban healthcare facility distribution and optimize the location of new healthcare facilities.

  8. Effect of Vegetation Patterns on SAR derived Surface Soil Moisture Distribution

    Science.gov (United States)

    Koyama, C. N.; Schneider, K.

    2012-12-01

    conditions, are used to derive biomass information independently from the soil moisture retrieval. Nevertheless, the canopy still has an attenuation effect on the co-polarized backscattering, but this can be corrected by using the vegetation information obtained from the other SAR observables. For constant permittivity states of the soil surface the canopy can have a disturbing effect of up to 6dB. This is the same order of magnitude of dynamic range as observed for soil moisture values ranging from 10 - 40 Vol.-% over bare surfaces. The present study is focused on the Rur catchment (Germany) where the effect of different vegetation patterns on the spatial distribution of near-surface soil water content is investigated by comparison between ALOS PALSAR derived biomass and soil moisture maps. The findings show that the impact of vegetation on the near-surface moisture contents may vary considerably. For wet and intermediate soil conditions where enough water is available for transpiration it was observed that the near-surface moisture content tends to be higher on vegetated fields. This may be explained by the fact that the canopy hampers evaporations due to lack of air movement while the plants uptake water from deeper soil layers. However if the water supply is low the plant water consumption can also lead to accelerated drying of the soil surface. This was especially observed for cereal crops.

  9. Integrating satellite actual evapotranspiration patterns into distributed model parametrization and evaluation for a mesoscale catchment

    Science.gov (United States)

    Demirel, M. C.; Mai, J.; Stisen, S.; Mendiguren González, G.; Koch, J.; Samaniego, L. E.

    2016-12-01

    Distributed hydrologic models are traditionally calibrated and evaluated against observations of streamflow. Spatially distributed remote sensing observations offer a great opportunity to enhance spatial model calibration schemes. For that it is important to identify the model parameters that can change spatial patterns before the satellite based hydrologic model calibration. Our study is based on two main pillars: first we use spatial sensitivity analysis to identify the key parameters controlling the spatial distribution of actual evapotranspiration (AET). Second, we investigate the potential benefits of incorporating spatial patterns from MODIS data to calibrate the mesoscale Hydrologic Model (mHM). This distributed model is selected as it allows for a change in the spatial distribution of key soil parameters through the calibration of pedo-transfer function parameters and includes options for using fully distributed daily Leaf Area Index (LAI) directly as input. In addition the simulated AET can be estimated at the spatial resolution suitable for comparison to the spatial patterns observed using MODIS data. We introduce a new dynamic scaling function employing remotely sensed vegetation to downscale coarse reference evapotranspiration. In total, 17 parameters of 47 mHM parameters are identified using both sequential screening and Latin hypercube one-at-a-time sampling methods. The spatial patterns are found to be sensitive to the vegetation parameters whereas streamflow dynamics are sensitive to the PTF parameters. The results of multi-objective model calibration show that calibration of mHM against observed streamflow does not reduce the spatial errors in AET while they improve only the streamflow simulations. We will further examine the results of model calibration using only multi spatial objective functions measuring the association between observed AET and simulated AET maps and another case including spatial and streamflow metrics together.

  10. Body mass and wing shape explain variability in broad-scale bird species distributions of migratory passerines along an ecological barrier during stopover.

    Science.gov (United States)

    Buler, Jeffrey J; Lyon, Rebecca J; Smolinsky, Jaclyn A; Zenzal, Theodore J; Moore, Frank R

    2017-08-29

    Migrating birds are under selective pressure to complete long-distance flights quickly and efficiently. Wing morphology and body mass influence energy expenditure of flight, such that certain characteristics may confer a greater relative advantage when making long crossings over ecological barriers by modifying the flight range or speed. We explored the possibility, among light (mass body mass have a lower margin for error in dealing with the exigencies of a long water crossing across the Gulf of Mexico and consequently minimize their travel time or distance. We found that species-mean fat-free body mass and wing tip pointedness independently explained variability among species distributions within ~50 km from the northern coast. In both spring and autumn, lighter (i.e., slower flying) species and species with more rounded wings were concentrated nearest the coastline. Our results support the idea that morphology helps to shape broad-scale bird distributions along an ecological barrier and that migration exerts some selective force on passerine morphology. Furthermore, smaller species with less-efficient flight appear constrained to stopping over in close proximity to ecological barriers, illustrating the importance of coastal habitats for small passerine migrants.

  11. Patterns of shift in ADC distributions in abdominal tumours during chemotherapy - feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Kirsteen; Olsen, Oeystein E. [Great Ormond Street Hospital for Children NHS Trust, Radiology Department, London (United Kingdom); Sebire, Neil J. [Great Ormond Street Hospital for Children NHS Trust, Histopathology Department, London (United Kingdom); Anderson, John [Great Ormond Street Hospital for Children NHS Trust, Oncology Department, London (United Kingdom)

    2011-01-15

    Apparent diffusion coefficient (ADC) relates to tissue cellularity, and change in ADC during chemotherapy may be a promising tool for assessing oncological response. To investigate the feasibility of measuring changes in ADC distribution in solid abdominal and pelvic paediatric tumours during chemotherapy, and to assess patterns of change. Consecutive children were included in a prospective observational study. ADC maps were calculated at presentation and following chemotherapy from a diffusion-sensitised sequence. ADC distribution in the whole tumour, excluding areas of low or absent gadolinium-enhancement, was investigated. Change during chemotherapy was assessed for each patient individually. Histopathological slices from the resected specimens were reviewed. There were seven children (nine tumours) included in the study. ADC in all except one deviated from a normal distribution. All tumours changed their ADC distribution during chemotherapy. Median ADC increased in all upper abdominal tumours, but more in tumours with histopathologically good or marked response to chemotherapy. Seven out of nine tumours attained a wider ADC distribution, the remaining two showed little chemotherapy response. ADC distribution changes during chemotherapy in childhood abdominal tumours are measurable. Distinct patterns of shift can be observed and ADC change is therefore promising as a noninvasive biomarker for therapy response. (orig.)

  12. Design pattern mining using distributed learning automata and DNA sequence alignment.

    Directory of Open Access Journals (Sweden)

    Mansour Esmaeilpour

    Full Text Available CONTEXT: Over the last decade, design patterns have been used extensively to generate reusable solutions to frequently encountered problems in software engineering and object oriented programming. A design pattern is a repeatable software design solution that provides a template for solving various instances of a general problem. OBJECTIVE: This paper describes a new method for pattern mining, isolating design patterns and relationship between them; and a related tool, DLA-DNA for all implemented pattern and all projects used for evaluation. DLA-DNA achieves acceptable precision and recall instead of other evaluated tools based on distributed learning automata (DLA and deoxyribonucleic acid (DNA sequences alignment. METHOD: The proposed method mines structural design patterns in the object oriented source code and extracts the strong and weak relationships between them, enabling analyzers and programmers to determine the dependency rate of each object, component, and other section of the code for parameter passing and modular programming. The proposed model can detect design patterns better that available other tools those are Pinot, PTIDEJ and DPJF; and the strengths of their relationships. RESULTS: The result demonstrate that whenever the source code is build standard and non-standard, based on the design patterns, then the result of the proposed method is near to DPJF and better that Pinot and PTIDEJ. The proposed model is tested on the several source codes and is compared with other related models and available tools those the results show the precision and recall of the proposed method, averagely 20% and 9.6% are more than Pinot, 27% and 31% are more than PTIDEJ and 3.3% and 2% are more than DPJF respectively. CONCLUSION: The primary idea of the proposed method is organized in two following steps: the first step, elemental design patterns are identified, while at the second step, is composed to recognize actual design patterns.

  13. Design Pattern Mining Using Distributed Learning Automata and DNA Sequence Alignment

    Science.gov (United States)

    Esmaeilpour, Mansour; Naderifar, Vahideh; Shukur, Zarina

    2014-01-01

    Context Over the last decade, design patterns have been used extensively to generate reusable solutions to frequently encountered problems in software engineering and object oriented programming. A design pattern is a repeatable software design solution that provides a template for solving various instances of a general problem. Objective This paper describes a new method for pattern mining, isolating design patterns and relationship between them; and a related tool, DLA-DNA for all implemented pattern and all projects used for evaluation. DLA-DNA achieves acceptable precision and recall instead of other evaluated tools based on distributed learning automata (DLA) and deoxyribonucleic acid (DNA) sequences alignment. Method The proposed method mines structural design patterns in the object oriented source code and extracts the strong and weak relationships between them, enabling analyzers and programmers to determine the dependency rate of each object, component, and other section of the code for parameter passing and modular programming. The proposed model can detect design patterns better that available other tools those are Pinot, PTIDEJ and DPJF; and the strengths of their relationships. Results The result demonstrate that whenever the source code is build standard and non-standard, based on the design patterns, then the result of the proposed method is near to DPJF and better that Pinot and PTIDEJ. The proposed model is tested on the several source codes and is compared with other related models and available tools those the results show the precision and recall of the proposed method, averagely 20% and 9.6% are more than Pinot, 27% and 31% are more than PTIDEJ and 3.3% and 2% are more than DPJF respectively. Conclusion The primary idea of the proposed method is organized in two following steps: the first step, elemental design patterns are identified, while at the second step, is composed to recognize actual design patterns. PMID:25243670

  14. Design pattern mining using distributed learning automata and DNA sequence alignment.

    Science.gov (United States)

    Esmaeilpour, Mansour; Naderifar, Vahideh; Shukur, Zarina

    2014-01-01

    Over the last decade, design patterns have been used extensively to generate reusable solutions to frequently encountered problems in software engineering and object oriented programming. A design pattern is a repeatable software design solution that provides a template for solving various instances of a general problem. This paper describes a new method for pattern mining, isolating design patterns and relationship between them; and a related tool, DLA-DNA for all implemented pattern and all projects used for evaluation. DLA-DNA achieves acceptable precision and recall instead of other evaluated tools based on distributed learning automata (DLA) and deoxyribonucleic acid (DNA) sequences alignment. The proposed method mines structural design patterns in the object oriented source code and extracts the strong and weak relationships between them, enabling analyzers and programmers to determine the dependency rate of each object, component, and other section of the code for parameter passing and modular programming. The proposed model can detect design patterns better that available other tools those are Pinot, PTIDEJ and DPJF; and the strengths of their relationships. The result demonstrate that whenever the source code is build standard and non-standard, based on the design patterns, then the result of the proposed method is near to DPJF and better that Pinot and PTIDEJ. The proposed model is tested on the several source codes and is compared with other related models and available tools those the results show the precision and recall of the proposed method, averagely 20% and 9.6% are more than Pinot, 27% and 31% are more than PTIDEJ and 3.3% and 2% are more than DPJF respectively. The primary idea of the proposed method is organized in two following steps: the first step, elemental design patterns are identified, while at the second step, is composed to recognize actual design patterns.

  15. Distribution patterns of fish assemblages in an Eastern Mediterranean intermittent river

    Directory of Open Access Journals (Sweden)

    Vardakas L.

    2015-01-01

    Full Text Available The distribution patterns of fish assemblages within streams can provide insights for river type classifications and may warrant specific conservation actions. However, there is limited knowledge of how fish assemblages assort along a longitudinal axis in Mediterranean intermittent streams. Patterns in spatial and temporal distribution of fish communities were analysed in a Mediterranean intermittent river (Evrotas River located in Southern Greece, hosting three endemic range restricted species of high conservation concern, during the period 2007−2009, with 80% of the river’s total length desiccating in the 2007 and 2008 droughts. The general trend was an increase in fish density and species richness along an upstream-downstream gradient. Fish assemblages from upstream to downstream were characterized by a decrease of the most rheophilic species (Squalius keadicus and an increase of the most stagnophilic species (Tropidophoxinellus spartiaticus. Three river segments, characterized by a high degree of homogeneity were delineated. Habitat and environmental preferences for the studied fish species were identified, with elevation and low flowing habitats being the most important environmental factors affecting fish distribution patterns. The current study provides evidence that even in an intermittent river an assemblage pattern following a longitudinal gradient can be identified, mainly due to the lack of instream barriers that allows recolonization after flow resumption.

  16. Protein Adsorption Patterns and Analysis on IV Nanoemulsions—The Key Factor Determining the Organ Distribution

    Directory of Open Access Journals (Sweden)

    Mirko Jansch

    2012-12-01

    Full Text Available Intravenous nanoemulsions have been on the market for parenteral nutrition since the 1950s; meanwhile, they have also been used successfully for IV drug delivery. To be well tolerable, the emulsions should avoid uptake by the MPS cells of the body; for drug delivery, they should be target-specific. The organ distribution is determined by the proteins adsorbing them after injection from the blood (protein adsorption pattern, typically analyzed by two-dimensional polyacrylamide gel electrophoresis, 2-D PAGE. The article reviews the 2-D PAGE method, the analytical problems to be faced and the knowledge available on how the composition of emulsions affects the protein adsorption patterns, e.g., the composition of the oil phase, stabilizer layer and drug incorporation into the interface or oil core. Data were re-evaluated and compared, and the implications for the in vivo distribution are discussed. Major results are that the interfacial composition of the stabilizer layer is the main determining factor and that this composition can be modulated by simple processes. Drug incorporation affects the pattern depending on the localization of the drug (oil core versus interface. The data situation regarding in vivo effects is very limited; mainly, it has to be referred to in the in vivo data of polymeric nanoparticles. As a conclusion, determination of the protein adsorption patterns can accelerate IV nanoemulsion formulation development regarding optimized organ distribution and related pharmacokinetics.

  17. MartiTracks: a geometrical approach for identifying geographical patterns of distribution.

    Directory of Open Access Journals (Sweden)

    Susy Echeverría-Londoño

    Full Text Available Panbiogeography represents an evolutionary approach to biogeography, using rational cost-efficient methods to reduce initial complexity to locality data, and depict general distribution patterns. However, few quantitative, and automated panbiogeographic methods exist. In this study, we propose a new algorithm, within a quantitative, geometrical framework, to perform panbiogeographical analyses as an alternative to more traditional methods. The algorithm first calculates a minimum spanning tree, an individual track for each species in a panbiogeographic context. Then the spatial congruence among segments of the minimum spanning trees is calculated using five congruence parameters, producing a general distribution pattern. In addition, the algorithm removes the ambiguity, and subjectivity often present in a manual panbiogeographic analysis. Results from two empirical examples using 61 species of the genus Bomarea (2340 records, and 1031 genera of both plants and animals (100118 records distributed across the Northern Andes, demonstrated that a geometrical approach to panbiogeography is a feasible quantitative method to determine general distribution patterns for taxa, reducing complexity, and the time needed for managing large data sets.

  18. Comparing Two Types of Fertilizer Distributor (centrifuge in Order to ptimize the Pattern of Fertilizer Distribution

    Directory of Open Access Journals (Sweden)

    P Ahmadi Moghaddam

    2013-09-01

    Full Text Available Increasing demand for food production in the recent years has raised the usage of granular fertilizers. Consequently, the growing use of fertilizers has reduced the quality and quantity of crop production. In addition pollution problems such as soil and water (surface and subterranean water contaminations has increased. Consistent spreading of fertilizers in the farmlands is of fundamental rules in conventional framings. In present study, the effects of the number and the arrangement (position of blades of a single disk fertilizer distributer and for two different fertilizers were investigated in order to obtain optimized distribution of fertilizer. The tests were conducted in factorial arrangement and in a completely randomized model. The variables were the number of blades in three levels of 4, 6 and 8, the blade position angles (in two patterns of radial and non-radial and the type of fertilizer (phosphate and nitrate. Statistical analysis of results indicated that the number of blades on the disk and type of fertilizer are not effective parameters in order to reach a consistent distribution pattern of fertilizer while the position of blades on the disk has significant influence for this purpose. The best pattern of distribution was obtained from the disk with four non-radial blades and nitrate fertilizer.

  19. Differential Survivorship of Invasive Mosquito Species in South Florida Cemeteries: Do Site-Specific Microclimates Explain Patterns of Coexistence and Exclusion?

    Science.gov (United States)

    LOUNIBOS, L. P.; O'MEARA, G. F.; JULIANO, S. A.; NISHIMURA, N.; ESCHER, R. L.; REISKIND, M. H.; CUTWA, M.; GREENE, K.

    2010-01-01

    Within 2 yr of the arrival of the invasive container mosquito Aedes albopictus (Skuse), the previously dominant invasive mosquito Aedes aegypti (L.) disappeared from many Florida cemeteries. At some cemeteries, however, Ae. aegypti populations seem stable despite Ae. albopictus invasion. We sought to understand this variation in the outcome (exclusion, coexistence) of this invasion, given that previous experiments show that Ae. albopictus is the superior larval competitor. We tested experimentally the hypothesis that climate-dependent egg survivorship differs between exclusion and coexistence cemeteries and that differences in invasion outcome are associated with microclimate. Viability of eggs oviposited in the laboratory and suspended in vases at six cemeteries was significantly greater for Ae. aegypti than for Ae. albopictus, and greater in 2001 than in 2006. Cemeteries differed significantly in egg survivorship of Ae. albopictus, but not of Ae. aegypti, which is consistent with the hypothesis that Ae. albopictus suffers site-specific, climate-driven egg mortality that mitigates the competitive superiority of larval Ae. albopictus. Principal component (PC) analysis of microclimate records from vases during the experiments yielded three PCs accounting for >96% of the variance in both years of experiments. Multivariate analysis of variance of the three PCs revealed significant microclimate differences among the six cemeteries and between exclusion versus coexistence cemeteries. Stepwise logistic regression of egg survivorship versus microclimate PCs yielded significant fits for both species, and twice as much variance explained for Ae. albopictus as for Ae. aegypti in both years. Higher mortalities in 2006 were associated with high average daily maximum temperatures in vases, with lethal thresholds for both species at ≈40°C. From 1990 to 2007, vase occupancy by Ae. albopictus increased and that by Ae. aegypti decreased, with increasing seasonal precipitation at

  20. Three-dimensional distribution of cortical synapses: a replicated point pattern-based analysis

    Science.gov (United States)

    Anton-Sanchez, Laura; Bielza, Concha; Merchán-Pérez, Angel; Rodríguez, José-Rodrigo; DeFelipe, Javier; Larrañaga, Pedro

    2014-01-01

    The biggest problem when analyzing the brain is that its synaptic connections are extremely complex. Generally, the billions of neurons making up the brain exchange information through two types of highly specialized structures: chemical synapses (the vast majority) and so-called gap junctions (a substrate of one class of electrical synapse). Here we are interested in exploring the three-dimensional spatial distribution of chemical synapses in the cerebral cortex. Recent research has showed that the three-dimensional spatial distribution of synapses in layer III of the neocortex can be modeled by a random sequential adsorption (RSA) point process, i.e., synapses are distributed in space almost randomly, with the only constraint that they cannot overlap. In this study we hypothesize that RSA processes can also explain the distribution of synapses in all cortical layers. We also investigate whether there are differences in both the synaptic density and spatial distribution of synapses between layers. Using combined focused ion beam milling and scanning electron microscopy (FIB/SEM), we obtained three-dimensional samples from the six layers of the rat somatosensory cortex and identified and reconstructed the synaptic junctions. A total volume of tissue of approximately 4500μm3 and around 4000 synapses from three different animals were analyzed. Different samples, layers and/or animals were aggregated and compared using RSA replicated spatial point processes. The results showed no significant differences in the synaptic distribution across the different rats used in the study. We found that RSA processes described the spatial distribution of synapses in all samples of each layer. We also found that the synaptic distribution in layers II to VI conforms to a common underlying RSA process with different densities per layer. Interestingly, the results showed that synapses in layer I had a slightly different spatial distribution from the other layers. PMID:25206325

  1. Distributional patterns of herbivore megamammals during the Late Pleistocene of South America

    Directory of Open Access Journals (Sweden)

    VALERIA GALLO

    2013-06-01

    Full Text Available The geographic distribution of 27 species of the South American megafauna of herbivore mammals during the Late Pleistocene was analyzed in order to identify their distributional patterns. The distribution of the species was studied using the panbiogeographical method of track analysis. Six generalized tracks (GTs and two biogeographic nodes were obtained. The GTs did not completely superpose with the areas of open savanna present in Pleistocene, nor with the biotic tracks of some arthropods typical of arid climate, indicating that these animals avoided arid environment. Overall, the GTs coincided with some biogeographic provinces defined on the basis of living taxa, indicating that certain current distributional patterns already existed in Pleistocene. The biogeographic nodes coincided with the borders between the main vegetal formations of the Pleistocene, showing that the type of vegetation had great influence in the distribution of the mammalian megafauna. The node 1 confirmed the existence of contact zones between paleobiogeographic regions near Argentina-Uruguay border. The node 2 connects the Brazilian Intertropical regions.

  2. Relationships between dendritic morphology, spatial distribution and firing patterns in rat layer 1 neurons

    Directory of Open Access Journals (Sweden)

    D.V.V. Santos

    2012-12-01

    Full Text Available The cortical layer 1 contains mainly small interneurons, which have traditionally been classified according to their axonal morphology. The dendritic morphology of these cells, however, has received little attention and remains ill defined. Very little is known about how the dendritic morphology and spatial distribution of these cells may relate to functional neuronal properties. We used biocytin labeling and whole cell patch clamp recordings, associated with digital reconstruction and quantitative morphological analysis, to assess correlations between dendritic morphology, spatial distribution and membrane properties of rat layer 1 neurons. A total of 106 cells were recorded, labeled and subjected to morphological analysis. Based on the quantitative patterns of their dendritic arbor, cells were divided into four major morphotypes: horizontal, radial, ascendant, and descendant cells. Descendant cells exhibited a highly distinct spatial distribution in relation to other morphotypes, suggesting that they may have a distinct function in these cortical circuits. A significant difference was also found in the distribution of firing patterns between each morphotype and between the neuronal populations of each sublayer. Passive membrane properties were, however, statistically homogeneous among all subgroups. We speculate that the differences observed in active membrane properties might be related to differences in the synaptic input of specific types of afferent fibers and to differences in the computational roles of each morphotype in layer 1 circuits. Our findings provide new insights into dendritic morphology and neuronal spatial distribution in layer 1 circuits, indicating that variations in these properties may be correlated with distinct physiological functions.

  3. Distributed Storage Algorithm for Geospatial Image Data Based on Data Access Patterns.

    Directory of Open Access Journals (Sweden)

    Shaoming Pan

    Full Text Available Declustering techniques are widely used in distributed environments to reduce query response time through parallel I/O by splitting large files into several small blocks and then distributing those blocks among multiple storage nodes. Unfortunately, however, many small geospatial image data files cannot be further split for distributed storage. In this paper, we propose a complete theoretical system for the distributed storage of small geospatial image data files based on mining the access patterns of geospatial image data using their historical access log information. First, an algorithm is developed to construct an access correlation matrix based on the analysis of the log information, which reveals the patterns of access to the geospatial image data. Then, a practical heuristic algorithm is developed to determine a reasonable solution based on the access correlation matrix. Finally, a number of comparative experiments are presented, demonstrating that our algorithm displays a higher total parallel access probability than those of other algorithms by approximately 10-15% and that the performance can be further improved by more than 20% by simultaneously applying a copy storage strategy. These experiments show that the algorithm can be applied in distributed environments to help realize parallel I/O and thereby improve system performance.

  4. Movement behaviour of the carabid beetle Pterostichus melanarius in crops and at a habitat interface explains patterns of population redistribution in the field.

    Directory of Open Access Journals (Sweden)

    Bas Allema

    Full Text Available Animals may respond to habitat quality and habitat edges and these responses may affect their distribution between habitats. We studied the movement behaviour of a ground-dwelling generalist predator, the carabid beetle Pterostichus melanarius (Illiger. We performed a mark-recapture experiment in two adjacent habitats; a large plot with oilseed radish (Raphanus sativus and a plot with rye (Secale cereale. We used model selection to identify a minimal model representing the mark-recapture data, and determine whether habitat-specific motility and boundary behaviour affected population redistribution. We determined movement characteristics of P. melanarius in laboratory arenas with the same plant species using video recording. Both the field and arena results showed preference behaviour of P. melanarius at the habitat interface. In the field, significantly more beetles moved from rye to oilseed radish than from radish to rye. In the arena, habitat entry was more frequent into oilseed radish than into rye. In the field, movement was best described by a Fokker-Planck diffusion model that contained preference behaviour at the interface and did not account for habitat specific motility. Likewise, motility calculated from movement data using the Patlak model was not different between habitats in the arena studies. Motility (m2 d-1 calculated from behavioural data resulted in estimates that were similar to those determined in the field. Thus individual behaviour explained population redistribution in the field qualitatively as well as quantitatively. The findings provide a basis for evaluating movement within and across habitats in complex agricultural landscapes with multiple habitats and habitat interfaces.

  5. Does the Arcto-Tertiary Biogeographic Hypothesis Explain the Disjunct Distribution of Northern Hemisphere Herbaceous Plants? The Case of Meehania (Lamiaceae)

    Science.gov (United States)

    Deng, Tao; Nie, Ze-Long; Drew, Bryan T.; Volis, Sergei; Kim, Changkyun; Xiang, Chun-Lei; Zhang, Jian-Wen; Wang, Yue-Hua; Sun, Hang

    2015-01-01

    Despite considerable progress, many details regarding the evolution of the Arcto-Tertiary flora, including the timing, direction, and relative importance of migration routes in the evolution of woody and herbaceous taxa of the Northern Hemisphere, remain poorly understood. Meehania (Lamiaceae) comprises seven species and five subspecies of annual or perennial herbs, and is one of the few Lamiaceae genera known to have an exclusively disjunct distribution between eastern Asia and eastern North America. We analyzed the phylogeny and biogeographical history of Meehania to explore how the Arcto-Tertiary biogeographic hypothesis and two possible migration routes explain the disjunct distribution of Northern Hemisphere herbaceous plants. Parsimony and Bayesian inference were used for phylogenetic analyses based on five plastid sequences (rbcL, rps16, rpl32-trnH, psbA-trnH, and trnL-F) and two nuclear (ITS and ETS) gene regions. Divergence times and biogeographic inferences were performed using Bayesian methods as implemented in BEAST and S-DIVA, respectively. Analyses including 11 of the 12 known Meehania taxa revealed incongruence between the chloroplast and nuclear trees, particularly in the positions of Glechoma and Meehania cordata, possibly indicating allopolyploidy with chloroplast capture in the late Miocene. Based on nrDNA, Meehania is monophyletic, and the North American species M. cordata is sister to a clade containing the eastern Asian species. The divergence time between the North American M. cordata and the eastern Asian species occurred about 9.81 Mya according to the Bayesian relaxed clock methods applied to the combined nuclear data. Biogeographic analyses suggest a primary role of the Arcto-Tertiary flora in the study taxa distribution, with a northeast Asian origin of Meehania. Our results suggest an Arcto-Tertiary origin of Meehania, with its present distribution most probably being a result of vicariance and southward migrations of populations during

  6. Size matters: point pattern analysis biases the estimation of spatial properties of stomata distribution.

    Science.gov (United States)

    Naulin, Paulette I; Valenzuela, Gerardo; Estay, Sergio A

    2017-03-01

    Stomata distribution is an example of biological patterning. Formal methods used to study stomata patterning are generally based on point-pattern analysis, which assumes that stomata are points and ignores the constraints imposed by size on the placement of neighbors. The inclusion of size in the analysis requires the use of a null model based on finite-size object geometry. In this study, we compare the results obtained by analyzing samples from several species using point and disc null models. The results show that depending on the null model used, there was a 20% reduction in the number of samples classified as uniform; these results suggest that stomata patterning is not as general as currently reported. Some samples changed drastically from being classified as uniform to being classified as clustered. In samples of Arabidopsis thaliana, only the disc model identified clustering at high densities of stomata. This reinforces the importance of selecting an appropriate null model to avoid incorrect inferences about underlying biological mechanisms. Based on the results gathered here, we encourage researchers to abandon point-pattern analysis when studying stomata patterning; more realistic conclusions can be drawn from finite-size object analysis. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  7. Mammographic Breast Density in Chinese Women: Spatial Distribution and Autocorrelation Patterns.

    Science.gov (United States)

    Lai, Christopher W K; Law, Helen K W

    2015-01-01

    Mammographic breast density (MBD) is a strong risk factor for breast cancer. The spatial distribution of MBD in the breast is variable and dependent on physiological, genetic, environmental and pathological factors. This pilot study aims to define the spatial distribution and autocorrelation patterns of MBD in Chinese women aged 40-60. By analyzing their digital mammographic images using a public domain Java image processing program for segmentation and quantification of MBD, we found their left and right breasts were symmetric to each other in regard to their breast size (Total Breast Area), the amount of BMD (overall PD) and Moran's I values. Their MBD was also spatially autocorrelated together in the anterior part of the breast in those with a smaller breast size, while those with a larger breast size tend to have their MBD clustered near the posterior part of the breast. Finally, we observed that the autocorrelation pattern of MBD was dispersed after a 3-year observation period.

  8. Historical distribution patterns of trigonioidids (non-marine Cretaceous bivalves) in Asia and their palaeogeographic significance

    Science.gov (United States)

    Sha, Jingeng

    2010-01-01

    The non-marine trigonioidid bivalves show five phases of radiation in the Cretaceous of Pal-Asia: pre-Aptian (?Valanginian/Hauterivian–Barremian), Aptian, Albian, Cenomanian and Turonian–Maastrichtian. Their distribution patterns show two distinct palaeo-river systems feeding trigonioidids. Before the Cenomanian, the river system occupied the southwestern–southern–southeastern Pal-Asian continental margin areas. During the Turonian–Maastrichtian, it extended along the line of southcentral China−eastern China−northeastern China−northern China and Mongolia−northwestern China–eastern Fergana Basin of Kyrgyzstan−western Tajikistan Basin of Tajikistan–Tashkent area of Kazakhstan−central Kyzylkum of northern Uzbekistan–Aral Sea area of Kazakhstan. Furthermore, the general trigonioidid distribution pattern demonstrates that Japan was probably attached to part of eastern China and/or Korea during the ?Valanginian/Hauterivian–Cenomanian stages. PMID:19605391

  9. Synthesis of Seafood Catch, Distribution, and Consumption Patterns in the Gulf of Mexico Region

    Energy Technology Data Exchange (ETDEWEB)

    Steimle and Associates, Inc.

    1999-08-16

    The purpose of this task was to gather and assemble information that will provide a synthesis of seafood catch, distribution and consumption patterns for the Gulf of Mexico (GOM) region. This task was part of a U.S. Department of Energy (DOE)-sponsored project entitled ''Environmental and Economic Assessment of Discharges from Gulf of Mexico Region Oil and Gas Operations.'' Personal interviews were conducted with a total of 905 recreational fishermen and 218 commercial fishermen (inclusive of shrimpers, crabbers, oystermen and finfishermen) in Louisiana and Texas using survey questionnaires developed for the study. Results of these interviews detail the species and quantities caught, location of catch, mode of fishing, distribution of catch, family consumption patterns and demographics of the fishermen.

  10. Public policy and population distribution: developing appropriate indicators of settlement patterns

    OpenAIRE

    Mike Coombes; Simon Raybould

    2001-01-01

    In this paper we are concerned with the measurement of aspects of population distribution, or settlement patterns, and the use of these measures in public-policy contexts in particular. More specifically, we query the adequacy of the population-density indicator, which is widely used in statistical formulae such as those by which the British government allocates funding to English local authorities. Our approach is to work through a series of topics, starting with an introductory discussion o...

  11. Hypothesizing Origin, Migration Routes and Distribution Patterns of Gymnosperms in Taiwan

    Directory of Open Access Journals (Sweden)

    Shing-Fan Huang

    2014-06-01

    Full Text Available Phytogeographical study of gymnosperms in Taiwan is carried out based on reviewing data gathered from published papers on fossils, phylogeny and phylogeography. Following questions are asked. (1 How is the high degree of endemism of gymnosperm flora of Taiwan derived? (2 How many source areas of gymnosperms in Taiwan are there? (3 Is there relation between distribution pattern of endemic gymnosperms in Taiwan and those of their sister species? (4 How do gymnosperms migrate to Taiwan?

  12. Distribution patterns of influenza virus receptors and viral attachment patterns in the respiratory and intestinal tracts of seven avian species

    Directory of Open Access Journals (Sweden)

    Costa Taiana

    2012-04-01

    Full Text Available Abstract This study assessed the presence of sialic acid α-2,3 and α-2,6 linked glycan receptors in seven avian species. The respiratory and intestinal tracts of the chicken, common quail, red-legged partridge, turkey, golden pheasant, ostrich, and mallard were tested by means of lectin histochemistry, using the lectins Maackia amurensis agglutinin II and Sambucus nigra agglutinin, which show affinity for α-2,3 and α-2,6 receptors, respectively. Additionally, the pattern of virus attachment (PVA was evaluated with virus histochemistry, using an avian-origin H4N5 virus and a human-origin seasonal H1N1 virus. There was a great variation of receptor distribution among the tissues and avian species studied. Both α-2,3 and α-2,6 receptors were present in the respiratory and intestinal tracts of the chicken, common quail, red-legged partridge, turkey, and golden pheasant. In ostriches, the expression of the receptor was basically restricted to α-2,3 in both the respiratory and intestinal tracts and in mallards the α-2,6 receptors were absent from the intestinal tract. The results obtained with the lectin histochemistry were, in general, in agreement with the PVA. The differential expression and distribution of α-2,3 and α-2,6 receptors among various avian species might reflect a potentially decisive factor in the emergence of new viral strains.

  13. Foraging pattern, colony distribution, and foraging range of the Florida harvester ant, Pogonomyrmex badius

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, J.S. (Savannah River Ecology Laboratory); Gentry, J.B.; Aiken, S.C.

    1981-12-01

    This report describes the foraging pattern of the Florida harvester ant Pogonomyrmex badius in a high-density population of colonies. The foraging pattern has both promoted and been influenced by the colony distribution. Pogonomyrmex badius forages from short trails which extend into a surrounding foraging range. Direction of foraging trails is influenced by the location of a colony's near neighbors. Seasonal nest relocations always occur along a foraging trail, usually the main trail. Foraging ranges are not actively defended, but are used almost exclusively by foragers from a single colony. Foraging ranges will be extended into an area abandoned by neighboring foragers, indicating that forager presence may define each colony's range. Colony distribution has remained essentially the same for several years, despite seasonal nest relocations and addition of new colonies. Establishment of trails and exclusive foraging ranges by each colony minimizes encounters with neighboring foragers and guarantees access to available resources; this pattern also promotes maintenance of the existing colony distribution and partitioning of resources.

  14. Foraging pattern, colony distribution, and foraging range of the Florida harvester ant Pogonomyrmex badius

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, J.S.; Gentry, J.B.

    1981-12-01

    This report describes the foraging pattern of the Florida harvester ant Pogonomyrmex badius in a high-density population of colonies. The foraging pattern has both promoted and been influenced by the colony distribution. Pogonomyrmex badius forages from short trails which extend into a surrounding foraging range. Direction of foraging trails is influenced by the location of a colony's near neighbors. Seasonal nest relocations always occur along a foraging trail, usually the main trail. Foraging ranges are not actively defended, but are used almost exclusively by foragers from a single colony. Foraging ranges will be extended into an area abondoned by neighboring foragers, indicating that forager presence may define each colony's range. Colony distribution has remained essentially the same for several years, despite seasonal nest relocations and addition of new colonies. Establishment of trails and exclusive foraging ranges by each colony minimizes encounters with neighboring foragers and guarantees access to available resources; this pattern also pomotes maintenance of the existing colony distribution and partitioning of resources.

  15. Patterns of distribution of the helminth parasites of freshwater fishes of Mexico.

    Science.gov (United States)

    Quiroz-Martínez, Benjamín; Salgado-Maldonado, Guillermo

    2013-01-01

    In order to draw patterns in helminth parasite composition and species richness in Mexican freshwater fishes we analyse a presence-absence matrix representing every species of adult helminth parasites of freshwater fishes from 23 Mexican hydrological basins. We examine the distributional patterns of the helminth parasites with regard to the main hydrological basins of the country, and in doing so we identify areas of high diversity and point out the biotic similarities and differences among drainage basins. Our dataset allows us to evaluate the relationships among drainage basins in terms of helminth diversity. This paper shows that the helminth fauna of freshwater fishes of Mexico can characterise hydrological basins the same way as fish families do, and that the basins of south-eastern Mexico are home to a rich, predominantly Neotropical, helminth fauna whereas the basins of the Mexican Highland Plateau and the Nearctic area of Mexico harbour a less diverse Nearctic fauna, following the same pattern of distribution of their fish host families. The composition of the helminth fauna of each particular basin depends on the structure of the fish community rather than on the limnological characteristics and geographical position of the basin itself. This work shows distance decay of similarity and a clear linkage between host and parasite distributions.

  16. Patterns, biases and prospects in the distribution and diversity of Neotropical snakes.

    Science.gov (United States)

    Guedes, Thaís B; Sawaya, Ricardo J; Zizka, Alexander; Laffan, Shawn; Faurby, Søren; Pyron, R Alexander; Bérnils, Renato S; Jansen, Martin; Passos, Paulo; Prudente, Ana L C; Cisneros-Heredia, Diego F; Braz, Henrique B; Nogueira, Cristiano de C; Antonelli, Alexandre; Meiri, Shai

    2018-01-01

    We generated a novel database of Neotropical snakes (one of the world's richest herpetofauna) combining the most comprehensive, manually compiled distribution dataset with publicly available data. We assess, for the first time, the diversity patterns for all Neotropical snakes as well as sampling density and sampling biases. We compiled three databases of species occurrences: a dataset downloaded from the Global Biodiversity Information Facility (GBIF), a verified dataset built through taxonomic work and specialized literature, and a combined dataset comprising a cleaned version of the GBIF dataset merged with the verified dataset. Neotropics, Behrmann projection equivalent to 1° × 1°. Specimens housed in museums during the last 150 years. Squamata: Serpentes. Geographical information system (GIS). The combined dataset provides the most comprehensive distribution database for Neotropical snakes to date. It contains 147,515 records for 886 species across 12 families, representing 74% of all species of snakes, spanning 27 countries in the Americas. Species richness and phylogenetic diversity show overall similar patterns. Amazonia is the least sampled Neotropical region, whereas most well-sampled sites are located near large universities and scientific collections. We provide a list and updated maps of geographical distribution of all snake species surveyed. The biodiversity metrics of Neotropical snakes reflect patterns previously documented for other vertebrates, suggesting that similar factors may determine the diversity of both ectothermic and endothermic animals. We suggest conservation strategies for high-diversity areas and sampling efforts be directed towards Amazonia and poorly known species.

  17. Can clusters based on caries experience and medical status explain the distribution of overhanging dental restorations and recurrent caries? A cross-sectional study in Madinah - Saudi Arabia.

    Science.gov (United States)

    Ghulam, Omar A; Fadel, Hani T

    2018-02-01

    Overhanging dental restorations (ODRs) and secondary caries lesions (SCLs) are of high prevalence and jeopardize the fate of the restoration. To assess the relationship between ODRs, SCLs and certain caries contributory factors. A total of 502 radiographic records of dental patients with proximal fillings (mean age 38 ± 13 years, 50% females) were screened for ODRs and SCLs. Descriptive and inferential statistics were used. In addition, two-step cluster analysis was performed in an attempt to explain trends in ODR and SCL distribution. A p value of ≤ 0.05 was considered statistically significant. More than 30% of the individuals had ODRs and SCLs. No differences between genders were observed ( p  > 0.05). Individuals with medical conditions had more ODRs than those without (49% vs. 34%, p  ≤ 0.05), while those with high caries experience had more SCLs (49%, p  ≤ 0.05). The cluster analysis grouped the participants in five clusters, with the cluster involving individuals with no medical conditions and low caries experience demonstrating the lowest prevalence of ODRs and SCLs. Within the study limits, more than one third of the sample of dental patients had ODRs and SCLs. The medical condition was associated with ODRs, while the past caries experience was associated with SCLs.

  18. Spatial Distribution Patterns in the Very Rare and Species-Rich Picea chihuahuana Tree Community (Mexico)

    Science.gov (United States)

    Wehenkel, Christian; Brazão-Protázio, João Marcelo; Carrillo-Parra, Artemio; Martínez-Guerrero, José Hugo; Crecente-Campo, Felipe

    2015-01-01

    The very rare Mexican Picea chihuahuana tree community covers an area of no more than 300 ha in the Sierra Madre Occidental. This special tree community has been the subject of several studies aimed at learning more about the genetic structure and ecology of the species and the potential effects of climate change. The spatial distribution of trees is a result of many ecological processes and can affect the degree of competition between neighbouring trees, tree density, variability in size and distribution, regeneration, survival, growth, mortality, crown formation and the biological diversity within forest communities. Numerous scale-dependent measures have been established in order to describe spatial forest structure. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. In this study, we examined the spatial distribution pattern of trees in the P. chihuahuana tree community in 12 localities, in relation to i) tree stand density, ii) diameter distribution (vertical structure), iii) tree species diversity, iv) geographical latitude and v) tree dominance at a fine scale (in 0.25 ha plots), with the aim of obtaining a better understanding of the complex ecosystem processes and biological diversity. Because of the strongly mixed nature of this tree community, which often produces low population densities of each tree species and random tree fall gaps caused by tree death, we expect aggregated patterns in individual Picea chihuahuana trees and in the P. chihuahuana tree community, repulsive Picea patterns to other tree species and repulsive patterns of young to adult trees. Each location was represented by one plot of 50 x 50 m (0.25 ha) established in the centre of the tree community. The findings demonstrate that the hypothesis of aggregated tree pattern is not applicable to the mean pattern measured by Clark-Evans index, Uniform Angle index and Mean Directional index of the uneven-aged P

  19. Spatial Distribution Patterns in the Very Rare and Species-Rich Picea chihuahuana Tree Community (Mexico.

    Directory of Open Access Journals (Sweden)

    Christian Wehenkel

    Full Text Available The very rare Mexican Picea chihuahuana tree community covers an area of no more than 300 ha in the Sierra Madre Occidental. This special tree community has been the subject of several studies aimed at learning more about the genetic structure and ecology of the species and the potential effects of climate change. The spatial distribution of trees is a result of many ecological processes and can affect the degree of competition between neighbouring trees, tree density, variability in size and distribution, regeneration, survival, growth, mortality, crown formation and the biological diversity within forest communities. Numerous scale-dependent measures have been established in order to describe spatial forest structure. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. In this study, we examined the spatial distribution pattern of trees in the P. chihuahuana tree community in 12 localities, in relation to i tree stand density, ii diameter distribution (vertical structure, iii tree species diversity, iv geographical latitude and v tree dominance at a fine scale (in 0.25 ha plots, with the aim of obtaining a better understanding of the complex ecosystem processes and biological diversity. Because of the strongly mixed nature of this tree community, which often produces low population densities of each tree species and random tree fall gaps caused by tree death, we expect aggregated patterns in individual Picea chihuahuana trees and in the P. chihuahuana tree community, repulsive Picea patterns to other tree species and repulsive patterns of young to adult trees. Each location was represented by one plot of 50 x 50 m (0.25 ha established in the centre of the tree community. The findings demonstrate that the hypothesis of aggregated tree pattern is not applicable to the mean pattern measured by Clark-Evans index, Uniform Angle index and Mean Directional index of the uneven

  20. Surface-Wettability Patterning for Distributing High-Momentum Water Jets on Porous Polymeric Substrates.

    Science.gov (United States)

    Sen, Uddalok; Chatterjee, Souvick; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Dodge, Richard; Yu, Lisha; Megaridis, Constantine M

    2018-02-07

    Liquid jet impingement on porous materials is particularly important in many applications of heat transfer, filtration, or in incontinence products. Generally, it is desired that the liquid not penetrate the substrate at or near the point of jet impact, but rather be distributed over a wider area before reaching the back side. A facile wettability-patterning technique is presented, whereby a water jet impinging orthogonally on a wettability-patterned nonwoven substrate is distributed on the top surface and through the porous matrix, and ultimately dispensed from prespecified points underneath the sample. A systematic approach is adopted to identify the optimum design that allows for a uniform distribution of the liquid on horizontally mounted substrates of ∼50 cm 2 area, with minimal or no spilling over the sample edges at jet flow rates exceeding 1 L/min. The effect of the location of jet impingement on liquid distribution is also studied, and the design is observed to perform well even under offset jet impact conditions.

  1. A spatial pattern analysis of the halophytic species distribution in an arid coastal environment.

    Science.gov (United States)

    Badreldin, Nasem; Uria-Diez, J; Mateu, J; Youssef, Ali; Stal, Cornelis; El-Bana, Magdy; Magdy, Ahmed; Goossens, Rudi

    2015-05-01

    Obtaining information about the spatial distribution of desert plants is considered as a serious challenge for ecologists and environmental modeling due to the required intensive field work and infrastructures in harsh and remote arid environments. A new method was applied for assessing the spatial distribution of the halophytic species (HS) in an arid coastal environment. This method was based on the object-based image analysis for a high-resolution Google Earth satellite image. The integration of the image processing techniques and field work provided accurate information about the spatial distribution of HS. The extracted objects were based on assumptions that explained the plant-pixel relationship. Three different types of digital image processing techniques were implemented and validated to obtain an accurate HS spatial distribution. A total of 2703 individuals of the HS community were found in the case study, and approximately 82% were located above an elevation of 2 m. The micro-topography exhibited a significant negative relationship with pH and EC (r = -0.79 and -0.81, respectively, p processes, in particular a hybrid family of Gibbs processes. A new model is proposed that uses a hard-core structure at very short distances, together with a cluster structure in short-to-medium distances and a Poisson structure for larger distances. This model was found to fit the data perfectly well.

  2. Investigating distribution pattern of species in a warm-temperate conifer-broadleaved-mixed forest in China for sustainably utilizing forest and soils.

    Science.gov (United States)

    Song, Houjuan; Xu, Yudan; Hao, Jing; Zhao, Bingqing; Guo, Donggang; Shao, Hongbo

    2017-02-01

    The maintaining mechanisms and potential ecological processes of species diversity in warm temperate- conifer-broadleaved-mixed forest are far from clear understanding. In this paper, the relative neighborhood density Ω was used to analyze the spatial distribution patterns of 34 species with ≥11 individuals in a warm- temperate-conifer-broadleaved-mixed forest, northern China. Then we used canonical correspondence analysis (CCA) and Torus-translation test (TTT) to explain the distribution of observed species. Our results show that aggregated distribution is the dominant pattern in warm-temperate natural forest and four species regular distribution at the spatial scale >30m. The aggregated percentage and intensity decline with spatial scale, abundance and size classes increasing. Rare species are aggregated more than intermediate and abundant species. These results prove sufficiently the effects existence of scale separation, self-thinning and Janzen-Connell hypothesis. In addition, functional traits (dispersal modes and shade tolerance) also have a significant influence on distribution of species. The results of CCA confirm that slope and convexity are the most important factors affecting the distribution of tree species distribution, elevation and slope of shrub species though the combination of topographic variables only explained 1% of distribution of tree species and 2% of shrub species. Most species don't have habitat preference; however 47.1% (16/34) species including absolutely dominant tree (Pinus tabulaeformis and Quercus wutaishanica) and shrub species (Rosa xanthina) and most other species with important value in the front, are strongly positively or negatively associated with at least one habitat. The valley and ridge are most distinct habitat with association of 12 species in the plot. However, high elevation slope with 257 quadrats is the most extensive habitat with only four species. Therefore, there is obvious evidence that habitat heterogeneity

  3. [Spatial distribution of human activities and their influences on landscape patterns in Daqingshan Nature Reserve].

    Science.gov (United States)

    Sun, Ya-Hui; Meng, Li; Tian, Lü; Li, Guo-Liang; Li, Yue-Hui; Sun, Jian-Xin

    2014-11-01

    Based on forest inventory data and field survey information, and by using GIS spatial analysis technique and landscape indices, this paper studied the spatial distribution of three categories of human activities (settlement, roads, and other sources of disturbances) and their impacts on landscape patterns in three sub-divided regions, i. e., the west, central and east regions of the Daqingshan Nature Reserve in Inner Mongolia. Results showed that the impacts of human activities were stronger in the east and west regions and weaker in the central region. Among the three subdivided regions, the landscape pattern in the west region was predominantly affected by other sources of disturbances, making the landscape patterns of coniferous forests, broadleaf forests and shrubs tended to be of aggregated distribution; the central region was mainly affected by roads, resulting in reduced landscape patch aggregation of broadleaf forests and shrubs; the east region was mostly affected by settlement, resulting in increased fragmentation of coniferous forests and broadleaf forests and apparent increases in landscape patch aggregation of shrubs and grasslands.

  4. Population ecology of Paepalanthus polyanthus (Bong. Kunth: temporal variation in the pattern of spatial distribution

    Directory of Open Access Journals (Sweden)

    Tânia Tarabini Castellani

    2004-11-01

    Full Text Available The temporal variation in density and pattern of spatial distribution of Paepalanthus polyanthus (BONG. Kunth (Eriocaulaceae were evaluated at a determinate sand dune. This study was carried out over a period of five years, at three permanent plots of 25m2 in a sand dune slack at Joaquina Beach, Florianópolis, SC, Brazil. There were strong density fluctuations throughout these years. In areas 1, 2 and 3, the densities changed from 10.4, 2.2 and 1.8 plants/m2 in December 1986 to 75.8, 11.4 and 45.6 plants/m2 in December 1991. Area 3, situated on an elevated site, presented greater variation in density, with no live plants in December 1989 and 102.2 plants/m2 at the recruitment observed in May 1990. Despite these density fluctuations, the pattern of spatial distribution was always aggregated (Id>1, P<0.05. The greatest Id values occurred in periods of low density and not in those of high density, associated with seedling recruitment. Factors such as high seed production with low dispersal, massive germination in moit years and a comparatively high death rate of seedlings at sites more subject to flooding or more distant from the water table proved themselves able to promote this aggregate pattern and increase it during plant development.

  5. High-resolution pattern of mangrove species distribution is controlled by surface elevation

    Science.gov (United States)

    Leong, Rick C.; Friess, Daniel A.; Crase, Beth; Lee, Wei Kit; Webb, Edward L.

    2018-03-01

    Mangrove vegetation species respond to multiple environmental gradients, and an enhanced understanding of how mangrove species are distributed across these gradients will facilitate conservation and management. Many environmental gradients correlate with tidal inundation; however small-scale inundation patterns resulting from microtopographical changes are difficult to capture empirically. In contrast, surface elevation is often a suitable, measurable and cost-effective proxy for inundation. This study investigated the relationships between species distribution and surface elevation in a mangrove forest in northwest Singapore. Through high-resolution land surveying, we developed a digital elevation model (DEM) and conducted a comprehensive survey of 4380 trees with a stem diameter ≥ 5 cm. A total of 15 species were encountered, and elevation envelopes were generated for 12. Species envelopes were distributed along an elevation continuum, with most species overlapping within the continuum. Spatial autocorrelation (SAC) was present for nine of the 15 species, and when taken into account, species ordering was modified across the elevation continuum. The presence of SAC strongly reinforces the need for research to control for SAC: classical spatial description of mangrove species distribution should be revised to account for ecological factors. This study suggests that (1) surface elevation applies strong controls on species distribution and (2) most mangroves at our study site have similar physiological tolerances.

  6. Modeling thalamocortical cell: impact of ca channel distribution and cell geometry on firing pattern.

    Science.gov (United States)

    Zomorrodi, Reza; Kröger, Helmut; Timofeev, Igor

    2008-01-01

    The influence of calcium channel distribution and geometry of the thalamocortical cell upon its tonic firing and the low threshold spike (LTS) generation was studied in a 3-compartment model, which represents soma, proximal and distal dendrites as well as in multi-compartment model using the morphology of a real reconstructed neuron. Using an uniform distribution of Ca(2+) channels, we determined the minimal number of low threshold voltage-activated calcium channels and their permeability required for the onset of LTS in response to a hyperpolarizing current pulse. In the 3-compartment model, we found that the channel distribution influences the firing pattern only in the range of 3% below the threshold value of total T-channel density. In the multi-compartmental model, the LTS could be generated by only 64% of unequally distributed T-channels compared to the minimal number of equally distributed T-channels. For a given channel density and injected current, the tonic firing frequency was found to be inversely proportional to the size of the cell. However, when the Ca(2+) channel density was elevated in soma or proximal dendrites, then the amplitude of LTS response and burst spike frequencies were determined by the ratio of total to threshold number of T-channels in the cell for a specific geometry.

  7. Topographic distribution pattern of morphologically different G cells in the murine antral mucosa

    Directory of Open Access Journals (Sweden)

    Claudia Frick

    2017-09-01

    Full Text Available Gastrin-secreting enteroendocrine cells (G cells in the antrum play an important role in the regulation of gastric secretion, gastric motility and mucosal cell proliferation. Recently we have uncovered the existence of two subpopulations of G cells with pivotally different morphology and a distinct localization in the antral invaginations; the functional implications of the different G cell types are still elusive. In this study a transgenic mouse line in which EGFP is expressed under the control of a gastrin promoter was used to elucidate the distribution pattern of the two G cell types throughout the different regions of the antrum. The results of immunohistochemical analyses revealed that G cells were not equally distributed along the anterior/posterior axis of the antrum. The “typical” pyramidal- or roundish-shaped G cells, which are located in the basal region of the antral invaginations, were more abundant in the proximal antrum bordering the corpus region but less frequent in the distal antrum bordering the pylorus. In contrast, the “atypical” G cells, which are located in the upper part of the antral invaginations and have a spindle-like contour with long processes, were evenly distributed along the anterior/posterior axis. This characteristic topographic segregation supports the notion that the two G cell types may serve different functions. A comparison of the antrum specific G cells with the two pan-gastrointestinal enteroendocrine cell types, somatostatin-secreting D cells and serotonin-secreting enterochromaffin (EC cells, revealed a rather similar distribution pattern of G and D cells, but a fundamentally different distribution of EC cells. These observations suggest that distinct mechanisms govern the spatial segregation of enteroendocrine cells in the antrum mucosa.

  8. Diversity distribution patterns of Chinese endemic seed plant species and their implications for conservation planning.

    Science.gov (United States)

    Huang, Jihong; Huang, Jianhua; Lu, Xinghui; Ma, Keping

    2016-09-23

    Endemism is an important concept in biogeography and biodiversity conservation. China is one of the richest countries in biodiversity, with very high levels of plant endemism. In this study, we analysed the distribution patterns of diversity, the degree of differentiation, and the endemicity of Chinese endemic seed plants using the floristic unit as a basic spatial analysis unit and 11 indices. The analysis was based on distribution data of 24,951 native seed plant species (excluding subspecies and varieties) and 12,980 Chinese endemic seed plant species, which were sourced from both specimen records and published references. The distribution patterns of Chinese endemic flora were generally consistent but disproportionate across China for diversity, degree of differentiation and endemicity. The South Hengduan Mountains Subregion had the highest values for all indices. At the regional level, both the Hengduan Mountains and the Central China regions were highest in diversity and degrees of differentiation. However, both the rate of local endemic to native species and the rate of local to Chinese endemic species were highest in the Taiwan Region and the South Taiwan Region. The Hengduan Mountains Region and the Central China Region are two key conservation priority areas for Chinese endemic seed plants.

  9. Quantitative analysis of CT attenuation distribution patterns of nodule components for pathologic categorization of lung nodules

    Science.gov (United States)

    Zhou, Chuan; Chan, Heang-Ping; Wei, Jun; Hadjiiski, Lubomir M.; Chughtai, Aamer; Kazerooni, Ella A.

    2017-03-01

    We investigated the feasibility of classifying pathologic invasive nodules and pre-invasive or benign nodules by quantitative analysis of the CT attenuation distribution patterns and other radiomic features of lung nodule components. We developed a new 3D adaptive multi-component Expectation-Maximization (EM) analysis method to segment the solid and non-solid nodule components and the surrounding lung parenchymal region. Features were extracted to characterize the size, shape, and the CT attenuation distribution of the entire nodule as well as the individual regions. With permission of the National Lung Screening Trial (NLST) project, a data set containing the baseline low dose CT scans of 53 cases with known pathologic tumor type categorization was obtained. The 53 cases contain 45 invasive nodules (group 1) and 42 pre-invasive nodules (group 2). A logistic regression model (LRM) was built using leave-one-case-out resampling and receiver operating characteristic (ROC) analysis for classification of group 1 and group 2, using the pathologic categorization as ground truth. With 4 selected features, the LRM achieved a test area under the curve (AUC) value of 0.877+/-0.036. The results demonstrated that the pathologic invasiveness of lung adenocarcinomas could be categorized according to the CT attenuation distribution patterns of the nodule components manifested on LDCT images.

  10. Factors controlling spatial distribution patterns of biocrusts in a heterogeneous and topographically complex semiarid area

    Science.gov (United States)

    Chamizo, Sonia; Rodríguez-Caballero, Emilio; Roncero, Beatriz; Raúl Román, José; Cantón, Yolanda

    2016-04-01

    Biocrusts are widespread soil components in drylands all over the world. They are known to play key roles in the functioning of these regions by fixing carbon and nitrogen, regulating hydrological processes, and preventing from water and wind erosion, thus reducing the loss of soil resources and increasing soil fertility. The rate and magnitude of services provided by biocrusts greatly depend on their composition and developmental stage. Late-successional biocrusts such as lichens and mosses have higher carbon and nitrogen fixation rates, and confer greater protection against erosion and the loss of sediments and nutrients than early-successional algae and cyanobacteria biocrusts. Knowledge of spatial distribution patterns of different biocrust types and the factors that control their distribution is important to assess ecosystem services provided by biocrusts at large spatial scales and to improve modelling of biogeochemical processes and water and carbon balance in drylands. Some of the factors that condition biocrust cover and composition are incoming solar radiation, terrain attributes, vegetation distribution patterns, microclimatic variables and soil properties such as soil pH, texture, soil organic matter, soil nutrients and gypsum and CaCO3 content. However, the factors that govern biocrust distribution may vary from one site to another depending on site characteristics. In this study, we examined the influence of abiotic attributes on the spatial distribution of biocrust types in a complex heterogeneous badland system (Tabernas, SE Spain) where biocrust cover up to 50% of the soil surface. From the analysis of relationships between terrain attributes and proportional abundance of biocrust types, it was found that topography exerted a main control on the spatial distribution of biocrust types in this area. SW-facing slopes were dominated by physical soil crusts and were practically devoid of vegetation and biocrusts. Biocrusts mainly occupied the pediments

  11. Citril finches during the winter: patterns of distribution, the role of pines and implications for the conservation of the species

    Directory of Open Access Journals (Sweden)

    Borras, A.

    2010-06-01

    Full Text Available The Citril finch Serinus citrinella is a Paleartic endemic species that breeds in the subalpine mountain zones of western temperate Europe. The species seems to be suffering a serious decline in its northern range, mainly in the Black Forest and the NE of the Alps. Numerous reasons have been provided for this decline, but all of them have been related to breeding habitats. Given that the species undergoes an altitudinal migration and that during winter it may use very different habitats, a sound knowledge of the distribution patterns and habitats used outside the breeding period is needed to conduct adequate conservation policies and management. This information, however, is largely lacking. The aim of this paper was to determine the current habitat used by Citril finches in north-eastern Spain during the winter, to analyse habitat suitability and to study movements, by investigating the origin of birds that overwinter in Catalonia. Citril finch distribution was modelled using both discriminant analysis and maximum entropy modelling, on the basis of species occurrences during winter in Catalonia (data from 1972-2009. Results showed that the presence of two tree species, Black pine (Pinus nigra subsp. salzmanii and Scots pine (Pinus sylvestris, both as part of mixed open forests, and the presence of abundant farmland and arvensic plants -the two vegetation units located in a typical submediterranean context, where the warm temperatures (sunny days in late winter permit the cones to open-, were the ecological and bioclimatic variables that explain the distribution model. All these variables in tandem seem to be the key for the current potential distribution of the Citril finch in winter (AUCscores: training data AUC= 0.955; test data AUC = 0.953. We analyzed recoveries (N = 238 of 2,368 birds ringed at wintering grounds and 12,648 birds ringed at subalpine localities in the adjacent Pyrenees from 1977-2004. We found that in the study area, we

  12. Distribution patterns of invasive Monk parakeets (Myiopsitta monachus in an urban habitat

    Directory of Open Access Journals (Sweden)

    Rodríguez–Pastor, R.

    2012-01-01

    Full Text Available Several invasive species have been shown to have a marked preference for urban habitats. The study of the variables responsible for the distribution of these species within urban habitats should allow to predict which environmental variables are indicative of preferred habitat, and to design landscape characteristics that make these areas less conducive to these species. The Monk parakeet Myiopsitta monachus is an invasive species in many American and European countries, and cities are one of its most usual habitats in invaded areas. The aim of this paper was to identify the main factors that determine distribution of the Monk parakeet in Barcelona, one of the cities in the world with the highest parakeet density. We defined our model based on eight preselected variables using a generalized linear model (GLZ and evaluated the strength of support for each model using the AIC–based multi–model inference approach. We used parakeet density as a dependent variable, and an analysis restricted to occupied neighbourhoods provided a model with two key variables to explain the distribution of the species. Monk parakeets were more abundant in neighbourhoods with a high density of trees and a high percentage of people over 65 years. This is interpreted by the fact that parakeets use trees as food sources and support for the nests, and that older people often feed the species. Data support the ‘human–activity’ hypothesis to explain how invasive species can successfully establish in a non–native habitat, and stress how limiting food resources, especially food supplied by humans, may be the easiest way to exert some control on Monk parakeet populations.

  13. Mapping National Plant Biodiversity Patterns in South Korea with the MARS Species Distribution Model.

    Directory of Open Access Journals (Sweden)

    Hyeyeong Choe

    Full Text Available Accurate information on the distribution of existing species is crucial to assess regional biodiversity. However, data inventories are insufficient in many areas. We examine the ability of Multivariate Adaptive Regression Splines (MARS multi-response species distribution model to overcome species' data limitations and portray plant species distribution patterns for 199 South Korean plant species. The study models species with two or more observations, examines their contribution to national patterns of species richness, provides a sensitivity analysis of different range threshold cutoff approaches for modeling species' ranges, and presents considerations for species modeling at fine spatial resolution. We ran MARS models for each species and tested four threshold methods to transform occurrence probabilities into presence or absence range maps. Modeled occurrence probabilities were extracted at each species' presence points, and the mean, median, and one standard deviation (SD calculated to define data-driven thresholds. A maximum sum of sensitivity and specificity threshold was also calculated, and the range maps from the four cutoffs were tested using independent plant survey data. The single SD values were the best threshold tested for minimizing omission errors and limiting species ranges to areas where the associated occurrence data were correctly classed. Eight individual species range maps for rare plant species were identified that are potentially affected by resampling predictor variables to fine spatial scales. We portray spatial patterns of high species richness by assessing the combined range maps from three classes of species: all species, endangered and endemic species, and range-size rarity of all species, which could be used in conservation planning for South Korea. The MARS model is promising for addressing the common problem of few species occurrence records. However, projected species ranges are highly dependent on the

  14. Patterns, biases and prospects in the distribution and diversity of Neotropical snakes

    Science.gov (United States)

    Sawaya, Ricardo J.; Zizka, Alexander; Laffan, Shawn; Faurby, Søren; Pyron, R. Alexander; Bérnils, Renato S.; Jansen, Martin; Passos, Paulo; Prudente, Ana L. C.; Cisneros‐Heredia, Diego F.; Braz, Henrique B.; Nogueira, Cristiano de C.; Antonelli, Alexandre; Meiri, Shai

    2017-01-01

    Abstract Motivation We generated a novel database of Neotropical snakes (one of the world's richest herpetofauna) combining the most comprehensive, manually compiled distribution dataset with publicly available data. We assess, for the first time, the diversity patterns for all Neotropical snakes as well as sampling density and sampling biases. Main types of variables contained We compiled three databases of species occurrences: a dataset downloaded from the Global Biodiversity Information Facility (GBIF), a verified dataset built through taxonomic work and specialized literature, and a combined dataset comprising a cleaned version of the GBIF dataset merged with the verified dataset. Spatial location and grain Neotropics, Behrmann projection equivalent to 1° × 1°. Time period Specimens housed in museums during the last 150 years. Major taxa studied Squamata: Serpentes. Software format Geographical information system (GIS). Results The combined dataset provides the most comprehensive distribution database for Neotropical snakes to date. It contains 147,515 records for 886 species across 12 families, representing 74% of all species of snakes, spanning 27 countries in the Americas. Species richness and phylogenetic diversity show overall similar patterns. Amazonia is the least sampled Neotropical region, whereas most well‐sampled sites are located near large universities and scientific collections. We provide a list and updated maps of geographical distribution of all snake species surveyed. Main conclusions The biodiversity metrics of Neotropical snakes reflect patterns previously documented for other vertebrates, suggesting that similar factors may determine the diversity of both ectothermic and endothermic animals. We suggest conservation strategies for high‐diversity areas and sampling efforts be directed towards Amazonia and poorly known species. PMID:29398972

  15. Towards evenly distributed grazing patterns: including social context in sheep management strategies

    Directory of Open Access Journals (Sweden)

    Agustina di Virgilio

    2016-06-01

    Full Text Available Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock grazing on three different paddocks (with sizes from 80 to 1000 Ha during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets, age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females used more intensively the most preferred areas and low-ranked (i.e., yearlings used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour. Discussion. Although homogenization and segregation of

  16. Towards evenly distributed grazing patterns: including social context in sheep management strategies

    Science.gov (United States)

    Morales, Juan Manuel

    2016-01-01

    Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock) grazing on three different paddocks (with sizes from 80 to 1000 Ha) during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets), age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females) used more intensively the most preferred areas and low-ranked (i.e., yearlings) used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour). Discussion. Although homogenization and segregation of flocks by

  17. Distribution pattern of dorsal root ganglion neurons synthesizing nitric oxide synthase in different animal species.

    Science.gov (United States)

    Kolesár, Dalibor; Kolesárová, Mária; Kyselovič, Ján

    2017-04-01

    The main aim of the present review is to provide at first a short survey of the basic anatomical description of sensory ganglion neurons in relation to cell size, conduction velocity, thickness of myelin sheath, and functional classification of their processes. In addition, we have focused on discussing current knowledge about the distribution pattern of neuronal nitric oxide synthase containing sensory neurons especially in the dorsal root ganglia in different animal species; hence, there is a large controversy in relation to interpretation of the results dealing with this interesting field of research.

  18. [Study on distributed patterns of scoparone and ayapin in Dendrobium species from Yunnan].

    Science.gov (United States)

    Liu, Yan-Yan; Yu, Hong; Yuan, Feng; Zhou, Feng; Chen, Ye-Gao

    2013-11-01

    An HPLC method for determination of scoparone and ayapin was established for investigating the distributed patterns of scoparone and ayapin in 37 species of Dendrobium. The contents of scoparone and ayapin in varied collected samples were determined by the established HPLC method. The pseudo-bulbs sampled were collected according to different growth age of D. thyrsiflorum. The results showed that the contents of scoparone and ayapin were much differently distributed in species of Dendrobium. Only D. thyrsiflorum and D. densfilorum contained both scoparone and ayapin, the content decreased with the growth age. A fewer amount of ayapin was tested in D. loddigesii from Wenshan. The scoparone and ayapin were not determined in the rest species of Dendrobium. The method was concise, sensitive, accurate and reproducible. It could be applied to assay scoparone and ayapin in populations of herbal Dendrobium.

  19. The Tara Oceans voyage reveals global diversity and distribution patterns of marine planktonic ciliates

    Science.gov (United States)

    Gimmler, Anna; Korn, Ralf; de Vargas, Colomban; Audic, Stéphane; Stoeck, Thorsten

    2016-01-01

    Illumina reads of the SSU-rDNA-V9 region obtained from the circumglobal Tara Oceans expedition allow the investigation of protistan plankton diversity patterns on a global scale. We analyzed 6,137,350 V9-amplicons from ocean surface waters and the deep chlorophyll maximum, which were taxonomically assigned to the phylum Ciliophora. For open ocean samples global planktonic ciliate diversity is relatively low (ca. 1,300 observed and predicted ciliate OTUs). We found that 17% of all detected ciliate OTUs occurred in all oceanic regions under study. On average, local ciliate OTU richness represented 27% of the global ciliate OTU richness, indicating that a large proportion of ciliates is widely distributed. Yet, more than half of these OTUs shared oceanic carbonate system and temperature. Planktonic ciliates displayed distinct vertical distributions relative to chlorophyll a. In contrast, the Tara Oceans dataset did not reveal any evidence that latitude is structuring ciliate communities. PMID:27633177

  20. Petechiae: reproducible pattern of distribution and increased appearance after bed rest.

    Science.gov (United States)

    Ganse, Bergita; Limper, Ulrich; Bühlmeier, Judith; Rittweger, Jörn

    2013-08-01

    Exposure to acceleration can cause petechial hemorrhages, called G measles. Petechiae usually start to develop between 5 and 9 G with a high interindividual variance. Centrifuge training delays the onset to higher G levels. One might expect onset at lower G levels after bed rest; however, there is no evidence in the literature. A case of petechiae formation after bed rest is presented here. Orthostatic tolerance was tested using a tilt table and lower body negative pressure before and after bed rest in both campaigns of a 2 x 21-d bed rest study with 6 degrees head-down tilt. A 42-yr-old male Caucasian without any history of thrombosis, venous disease, hemorrhage, or petechiae, and with a negative thrombophilia screening, took part in the bed rest study as 1 out of 10 subjects. He was the only one to develop petechiae during the orthostatic tests after, but not before, bed rest in both campaigns. Petechiae were distributed throughout the lower legs and most pronounced at the shin in a stocking-like fashion, surprisingly reoccurring in an identical pattern of distribution. Petechiae appeared slowly over minutes during hyperemia. This case indicates that prolonged bed rest decreases the threshold for petechiae formation. A reproducible distribution pattern suggests that factors predisposing to petechiae formation keep their local distribution over time (possibly due to local vessel structures). Mechanisms of adaptation and interindividual variance are unclear. Findings are of clinical relevance as such cases might occur after prolonged bed rest in patients without need of expensive testing.

  1. Local knowledge, use pattern and geographical distribution of Moringa oleifera Lam. (Moringaceae) in Nigeria.

    Science.gov (United States)

    Popoola, Jacob O; Obembe, Olawole O

    2013-11-25

    All parts of Moringa oleifera are medicinally valuable with overlapping uses in treating myriads of ailments and diseases including body pains and weakness, fever, asthma, cough, blood pressure, arthritis, diabetes, epilepsy, wound, and skin infection. Moringa also has robust ability to challenge terminal diseases such as HIV/AIDs infections, chronic anemia, cancer, malaria and hemorrhage. The present study was to obtain ethnobotanical information on the use and local knowledge variation, geographical distribution, and to collect different landraces of Moringa oleifera from the different agro-ecological regions in Nigeria, for further studies. Ethnobotanical data were collected through face to face interviews, semi structured questionnaires and discussions with selected people who had knowledge about the plant. The fidelity level (FL %) and use value for different use categories of Moringa oleifera and its parts were estimated. The variation in ethnobotanical knowledge was evaluated by comparing the mean use value among ethnic, gender and age groups using sample T test. Garmi GPS was used to determine the locations (latitude and longitude) and height in different areas to assess the geographical spread of the species. Seven (7) categories of use (Food, medicine, fodder, fencing, firewood, gum and coagulant) were recorded for Moringa oleifera. Food and medicinal uses showed highest fidelity level while the leaves and the seeds were the plant parts most utilized for the same purposes. There were significant differences among the ethnic, gender and age groups regarding the ethno-botanical use value. The geographical distribution pattern shows that the Moringa oleifera is well distributed in all ecological zones of Nigeria, well adapted to the varied climatic conditions and gaining unprecedented awareness among the people. Though considered an introduced species, Moringa oleifera has found wide acceptance, recognition and usefulness among the various ethnicities in the

  2. Common distribution patterns of marsupials related to physiographical diversity in Venezuela.

    Science.gov (United States)

    Ventura, Jacint; Bagaria, Guillem; Sans-Fuentes, Maria Assumpció; Pérez-Hernández, Roger

    2014-01-01

    The aim of this study is to identify significant biotic regions (groups of areas with similar biotas) and biotic elements (groups of taxa with similar distributions) for the marsupial fauna in a part of northern South America using physiographical areas as Operational Geographical Units (OGUs). We considered Venezuela a good model to elucidate this issue because of its high diversity in landscapes and the relatively vast amount of information available on the geographical distribution of marsupial species. Based on the presence-absence of 33 species in 15 physiographical sub-regions (OGUs) we identified Operational Biogeographical Units (OBUs) and chorotypes using a quantitative analysis that tested statistical significance of the resulting groups. Altitudinal and/or climatic trends in the OBUs and chorotypes were studied using a redundancy analysis. The classification method revealed four OBUs. Strong biotic boundaries separated: i) the xerophytic zone of the Continental coast (OBU I); ii) the sub-regions north of the Orinoco River (OBU III and IV); and those south to the river (OBU II). Eleven chorotypes were identified, four of which included a single species with a restricted geographic distribution. As for the other chorotypes, three main common distribution patterns have been inferred: i) species from the Llanos and/or distributed south of the Orinoco River; ii) species exclusively from the Andes; and iii) species that either occur exclusively north of the Orinoco River or that show a wide distribution throughout Venezuela. Mean altitude, evapotranspiration and precipitation of the driest month, and temperature range allowed us to characterize environmentally most of the OBUs and chorotypes obtained.

  3. Calibration of a distributed hydrologic model using observed spatial patterns from MODIS data

    Science.gov (United States)

    Demirel, Mehmet C.; González, Gorka M.; Mai, Juliane; Stisen, Simon

    2016-04-01

    Distributed hydrologic models are typically calibrated against streamflow observations at the outlet of the basin. Along with these observations from gauging stations, satellite based estimates offer independent evaluation data such as remotely sensed actual evapotranspiration (aET) and land surface temperature. The primary objective of the study is to compare model calibrations against traditional downstream discharge measurements with calibrations against simulated spatial patterns and combinations of both types of observations. While the discharge based model calibration typically improves the temporal dynamics of the model, it seems to give rise to minimum improvement of the simulated spatial patterns. In contrast, objective functions specifically targeting the spatial pattern performance could potentially increase the spatial model performance. However, most modeling studies, including the model formulations and parameterization, are not designed to actually change the simulated spatial pattern during calibration. This study investigates the potential benefits of incorporating spatial patterns from MODIS data to calibrate the mesoscale hydrologic model (mHM). This model is selected as it allows for a change in the spatial distribution of key soil parameters through the optimization of pedo-transfer function parameters and includes options for using fully distributed daily Leaf Area Index (LAI) values directly as input. In addition the simulated aET can be estimated at a spatial resolution suitable for comparison to the spatial patterns observed with MODIS data. To increase our control on spatial calibration we introduced three additional parameters to the model. These new parameters are part of an empirical equation to the calculate crop coefficient (Kc) from daily LAI maps and used to update potential evapotranspiration (PET) as model inputs. This is done instead of correcting/updating PET with just a uniform (or aspect driven) factor used in the mHM model

  4. Spatial patterns and frequency distributions of regional deformation in the healthy human lung.

    Science.gov (United States)

    Hurtado, Daniel E; Villarroel, Nicolás; Andrade, Carlos; Retamal, Jaime; Bugedo, Guillermo; Bruhn, Alejandro

    2017-08-01

    Understanding regional deformation in the lung has long attracted the medical community, as parenchymal deformation plays a key role in respiratory physiology. Recent advances in image registration make it possible to noninvasively study regional deformation, showing that volumetric deformation in healthy lungs follows complex spatial patterns not necessarily shared by all subjects, and that deformation can be highly anisotropic. In this work, we systematically study the regional deformation in the lungs of eleven human subjects by means of in vivo image-based biomechanical analysis. Regional deformation is quantified in terms of 3D maps of the invariants of the right stretch tensor, which are related to regional changes in length, surface and volume. Based on the histograms of individual lungs, we show that log-normal distributions adequately represent the frequency distribution of deformation invariants in the lung, which naturally motivates the normalization of the invariant fields in terms of the log-normal score. Normalized maps of deformation invariants allow for a direct intersubject comparison, as they display spatial patterns of deformation in a range that is common to all subjects. For the population studied, we find that lungs in supine position display a marked gradient along the gravitational direction not only for volumetric but also for length and surface regional deformation, highlighting the role of gravity in the regional deformation of normal lungs under spontaneous breathing.

  5. Type 2 diabetes mellitus patients manifest characteristic spatial EMG potential distribution pattern during sustained isometric contraction.

    Science.gov (United States)

    Watanabe, Kohei; Miyamoto, Toshiaki; Tanaka, Yoji; Fukuda, Kazuhito; Moritani, Toshio

    2012-09-01

    The purpose of the present study is to investigate spatial surface electromyography (SEMG) potential distribution pattern in type 2 diabetes mellitus (T2DM) patients. Nine T2DM patients and nine age-matched healthy men (CON) performed a sustained isometric knee extension at 10% of maximal voluntary contraction for 120s. Multi-channel SEMG was recorded from the vastus lateralis muscle by means of 64 electrodes. To characterize spatial SEMG potential distribution pattern, modified entropy and correlation coefficients between same electrode locations were calculated at 15, 60 and 120s for the root mean square values. At 60 and 120s, modified entropy in T2DM was significantly lower than those in CON (p<0.05). Correlation coefficients for T2DM were significantly higher than those for CON at 60 and 120s (p<0.05). From these results, we suggested that T2DM patients continue to recruit limited and same motor units during the sustained contraction at low force level. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  6. The Upper Mississippi River floodscape: spatial patterns of flood inundation and associated plant community distributions

    Science.gov (United States)

    DeJager, Nathan R.; Rohweder, Jason J.; Yin, Yao; Hoy, Erin E.

    2016-01-01

    Questions How is the distribution of different plant communities associated with patterns of flood inundation across a large floodplain landscape? Location Thirty-eight thousand nine hundred and seventy hectare of floodplain, spanning 320 km of the Upper Mississippi River (UMR). Methods High-resolution elevation data (Lidar) and 30 yr of daily river stage data were integrated to produce a ‘floodscape’ map of growing season flood inundation duration. The distributions of 16 different remotely sensed plant communities were quantified along the gradient of flood duration. Results Models fitted to the cumulative frequency of occurrence of different vegetation types as a function of flood duration showed that most types exist along a continuum of flood-related occurrence. The diversity of community types was greatest at high elevations (0–10 d of flooding), where both upland and lowland community types were found, as well as at very low elevations (70–180 d of flooding), where a variety of lowland herbaceous communities were found. Intermediate elevations (20–60 d of flooding) tended to be dominated by floodplain forest and had the lowest diversity of community types. Conclusions Although variation in flood inundation is often considered to be the main driver of spatial patterns in floodplain plant communities, few studies have quantified flood–vegetation relationships at broad scales. Our results can be used to identify targets for restoration of historical hydrological regimes or better anticipate hydro-ecological effects of climate change at broad scales.

  7. Habitat Preferences, Distribution Pattern, and Root Weight Estimation of Pasak Bumi (Eurycoma longifolia Jack.

    Directory of Open Access Journals (Sweden)

    Siti Masitoh Kartikawati

    2014-04-01

    Full Text Available Pasak bumi (Eurycoma longifolia Jack is one of non timber forest products with “indeterminate” conservation status and commercially traded in West Kalimantan. The research objective was to determine the potential of pasak bumi root per hectare and its ecological condition under natural habitat. Root weight of E. longifolia Jack was estimated using simple linear regression and exponential equation with stem diameter and height as independent variables. The results showed that the individual number of the population was 114 with the majority in seedling stage with 71 individuals (62.28%. The distribution was found in clumped pattern. Conditions of the habitat could be described as follows: daily average temperature of 25.6oC, daily average relative humidity of 73.6%, light intensity of 0.9 klx, and red-yellow podsolic soil with texture ranged from clay to sandy clay. The selected estimator model for E. longifolia Jack root weight used exponential equation with stem height as independent variable using the equation of Y= 21.99T0,010 and determination coefficient of 0.97. After height variable was added, the potential of E. longifolia Jack minimum root weight that could be harvested per hectare was 0.33 kg.Keywords: Eurycoma longifolia, habitat preference, distribution pattern, root weight

  8. Optimizing Client Latency in a Distributed System by Using the “Remote Façade” Design Pattern

    Directory of Open Access Journals (Sweden)

    Cosmin RABLOU

    2010-01-01

    Full Text Available In this paper we investigate the role of the Remote Façade pattern in the optimization of dis-tributed systems. The intent of this pattern is to wrap fine-grained remote objects in a coarse-grained interface and thus greatly reduce the total number of calls executed over the network. The measurement of the performance gain achieved by implementing this pattern is done through testing with a distributed application written in C# and using the latest Microsoft framework for distributed systems (Windows Communication Framework. Furthermore, we will be presenting the scenarios in which the implementation of the Remote Façade pattern brings a significant performance gain. Finally we show further scenarios in which the per-formance brought by this pattern can be investigated.

  9. Modeling the Spatial Distribution and Fruiting Pattern of a Key Tree Species in a Neotropical Forest: Methodology and Potential Applications

    National Research Council Canada - National Science Library

    Caillaud, Damien; Crofoot, Margaret C; Scarpino, Samuel V; Jansen, Patrick A; Garzon-Lopez, Carol X; Winkelhagen, Annemarie J. S; Bohlman, Stephanie A; Walsh, Peter D

    2010-01-01

    ... distributions of food resources. We illustrate our procedure by creating a detailed simulation model of fruit production patterns for Dipteryx oleifera, a keystone tree species, on Barro Colorado Island (BCI), Panama...

  10. Strain distribution across magmatic margins during the breakup stage: Seismicity patterns in the Afar rift zone

    Science.gov (United States)

    Brown, C.; Ebinger, C. J.; Belachew, M.; Gregg, T.; Keir, D.; Ayele, A.; Aronovitz, A.; Campbell, E.

    2008-12-01

    Fault patterns record the strain history along passive continental margins, but geochronological constraints are, in general, too sparse to evaluate these patterns in 3D. The Afar depression in Ethiopia provides a unique setting to evaluate the time and space relations between faulting and magmatism across an incipient passive margin that formed above a mantle plume. The margin comprises a high elevation flood basalt province with thick, underplated continental crust, a narrow fault-line escarpment underlain by stretched and intruded crust, and a broad zone of highly intruded, mafic crust lying near sealevel. We analyze fault and seismicity patterns across and along the length of the Afar rift zone to determine the spatial distribution of strain during the final stages of continental breakup, and its relation to active magmatism and dike intrusions. Seismicity data include historic data and 2005-2007 data from the collaborative US-UK-Ethiopia Afar Geodynamics Project that includes the 2005-present Dabbahu rift episode. Earthquake epicenters cluster within discrete, 50 km-long magmatic segments that lack any fault linkage. Swarms also cluster along the fault-line scarp between the unstretched and highly stretched Afar rift zone; these earthquakes may signal release of stresses generated by large lateral density contrasts. We compare Coulomb static stress models with focal mechanisms and fault kinematics to discriminate between segmented magma intrusion and crank- arm models for the central Afar rift zone.

  11. Large-scale spatial distribution patterns of gastropod assemblages in rocky shores.

    Directory of Open Access Journals (Sweden)

    Patricia Miloslavich

    Full Text Available Gastropod assemblages from nearshore rocky habitats were studied over large spatial scales to (1 describe broad-scale patterns in assemblage composition, including patterns by feeding modes, (2 identify latitudinal pattern of biodiversity, i.e., richness and abundance of gastropods and/or regional hotspots, and (3 identify potential environmental and anthropogenic drivers of these assemblages. Gastropods were sampled from 45 sites distributed within 12 Large Marine Ecosystem regions (LME following the NaGISA (Natural Geography in Shore Areas standard protocol (www.nagisa.coml.org. A total of 393 gastropod taxa from 87 families were collected. Eight of these families (9.2% appeared in four or more different LMEs. Among these, the Littorinidae was the most widely distributed (8 LMEs followed by the Trochidae and the Columbellidae (6 LMEs. In all regions, assemblages were dominated by few species, the most diverse and abundant of which were herbivores. No latitudinal gradients were evident in relation to species richness or densities among sampling sites. Highest diversity was found in the Mediterranean and in the Gulf of Alaska, while highest densities were found at different latitudes and represented by few species within one genus (e.g. Afrolittorina in the Agulhas Current, Littorina in the Scotian Shelf, and Lacuna in the Gulf of Alaska. No significant correlation was found between species composition and environmental variables (r≤0.355, p>0.05. Contributing variables to this low correlation included invasive species, inorganic pollution, SST anomalies, and chlorophyll-a anomalies. Despite data limitations in this study which restrict conclusions in a global context, this work represents the first effort to sample gastropod biodiversity on rocky shores using a standardized protocol across a wide scale. Our results will generate more work to build global databases allowing for large-scale diversity comparisons of rocky intertidal assemblages.

  12. Distinct distribution patterns of prokaryotes between sediment and water in the Yellow River estuary.

    Science.gov (United States)

    Wei, Guangshan; Li, Mingcong; Li, Fenge; Li, Han; Gao, Zheng

    2016-11-01

    There are close exchanges between sediment and water in estuaries; however, the patterns of prokaryotic community assembly in these two habitat types are still unclear. This study investigated the bacterial and archaeal abundance, diversity, and community composition in the sediment and the overlying water of the Yellow River estuary. Notably higher prokaryotic abundance and diversity were detected in the sediment than in the water, and bacterial abundance and diversity were remarkably higher than those of archaea. Furthermore, the ratio of bacterial to archaeal 16S rRNA gene abundance was significantly lower in the sediment than in the water. Bacterial communities at different taxonomic levels were apparently distinct between the sediment and water, but archaeal communities were not. The most dominant bacteria were affiliated with Deltaproteobacteria and Gammaproteobacteria in sediment and with Alphaproteobacteria and Betaproteobacteria in water. Euryarchaeota and Thaumarchaeota were the most abundant archaea in both habitats. Although distinct prokaryotic distribution patterns were observed, most of the dominant bacteria and archaea present were related to carbon, nitrogen, and sulfur cycling processes, such as methanogenesis, ammonia oxidation, and sulfate reduction. Unexpectedly, prokaryotes from the water showed a higher sensitivity to environmental factors, while only a few factors affected sediment communities. Additionally, some potential co-occurrence relationships between prokaryotes were also found in this study. These results suggested distinct distribution patterns of bacterial and archaeal communities between sediment and overlying water in this important temperate estuary, which may serve as a useful community model for the further ecological and evolutionary study of prokaryotes in estuarine ecosystems.

  13. Distribution patterns of muscle fibre types in major muscles of the bull (Bos taurus).

    Science.gov (United States)

    Totland, G K; Kryvi, H

    1991-01-01

    The study describes the variations in distribution and cross-sectional area (fibre size) of three muscle fibre types (I, IIA, IIB) in 34 of the largest muscles of the bull (Bos taurus). The animals had been kept strictly unexercised for one year before slaughter. Representative sampling was done at 15 positions within each muscle, and from 2700 to 4500 fibres were analysed in each muscle. Different intermuscular patterns are described. The overall volume fraction (%) of type I fibres was about 10% higher in the forepart muscles than in the hindpart muscles (41% and 31%, respectively), while the mean content of type IIB fibres was similar. Type I fibres were particularly abundant in antigravity muscles. Of these, the hindlimb muscles contained 50% more type I fibres (by weight) than those of the forelimb. Typical antigravity antagonists contained very few type I fibres. In the thigh cross-section the proportion of type I fibres was highest in the anterior and medial parts, while the IIB fibres tended to be concentrated in the superficial and posterior parts. Intramuscular patterns were revealed, with type I fibres becoming gradually more abundant from superficial to deep regions, while IIB fibres had an opposite distribution. This was particularly evident in the thigh proper and in the scapular region. Within each fasciculus of all the muscles, the muscle fibre types formed a general spatial pattern. Type I fibres in the muscles of the forepart were on average about 15% larger than those of the muscles in the hindpart. The IIB fibres were on average about 10% larger in the hindpart than in the forepart muscles. A covariation between the proportion of type I and IIB fibres and their cross-sectional area was indicated.

  14. Spatio-temporal patterns in acoustic presence and distribution of Antarctic blue whales Balaenoptera musculus intermedia in the Weddell Sea

    OpenAIRE

    Thomisch, Karolin; Boebel, Olaf; Clark, CW; Hagen, W.; Spiesecke, Stefanie; Zitterbart, Daniel; Van Opzeeland, Ilse

    2016-01-01

    Distribution and movement patterns of Antarctic blue whales Balaenoptera musculus intermedia at large temporal and spatial scales are still poorly understood. The objective of this study was to explore spatio-temporal distribution patterns of Antarctic blue whales in the Atlantic sector of the Southern Ocean, using passive acoustic monitoring data. Multi-year data were collected between 2008 and 2013 by 11 recorders deployed in the Weddell Sea and along the Greenwich meridian. Antarctic blue ...

  15. Predicting the distribution pattern of small carnivores in response to environmental factors in the Western Ghats.

    Directory of Open Access Journals (Sweden)

    Riddhika Kalle

    Full Text Available Due to their secretive habits, predicting the pattern of spatial distribution of small carnivores has been typically challenging, yet for conservation management it is essential to understand the association between this group of animals and environmental factors. We applied maximum entropy modeling (MaxEnt to build distribution models and identify environmental predictors including bioclimatic variables, forest and land cover type, topography, vegetation index and anthropogenic variables for six small carnivore species in Mudumalai Tiger Reserve. Species occurrence records were collated from camera-traps and vehicle transects during the years 2010 and 2011. We used the average training gain from forty model runs for each species to select the best set of predictors. The area under the curve (AUC of the receiver operating characteristic plot (ROC ranged from 0.81 to 0.93 for the training data and 0.72 to 0.87 for the test data. In habitat models for F. chaus, P. hermaphroditus, and H. smithii "distance to village" and precipitation of the warmest quarter emerged as some of the most important variables. "Distance to village" and aspect were important for V. indica while "distance to village" and precipitation of the coldest quarter were significant for H. vitticollis. "Distance to village", precipitation of the warmest quarter and land cover were influential variables in the distribution of H. edwardsii. The map of predicted probabilities of occurrence showed potentially suitable habitats accounting for 46 km(2 of the reserve for F. chaus, 62 km(2 for V. indica, 30 km(2 for P. hermaphroditus, 63 km(2 for H. vitticollis, 45 km(2 for H. smithii and 28 km(2 for H. edwardsii. Habitat heterogeneity driven by the east-west climatic gradient was correlated with the spatial distribution of small carnivores. This study exemplifies the usefulness of modeling small carnivore distribution to prioritize and direct conservation planning for habitat specialists

  16. Simulating water distribution patterns for fixed spray plate sprinkler using the ballistic theory

    Directory of Open Access Journals (Sweden)

    Sofiane Ouazaa

    2014-07-01

    Full Text Available Ballistic simulation of the spray sprinkler for self-propelled irrigation machines requires the incorporation of the effect of the jet impact with the deflecting plate. The kinetic energy losses produced by the jet impact with the spray plate were experimentally characterized for different nozzle sizes and two working pressures for fixed spray plate sprinklers (FSPS. A technique of low speed photography was used to determine drop velocity at the point where the jet is broken into droplets. The water distribution pattern of FSPS for different nozzle sizes, working at two pressures and under different wind conditions were characterized in field experiments. The ballistic model was calibrated to simulate water distribution in different technical and meteorological conditions. Field experiments and the ballistic model were used to obtain the model parameters (D50, n, K1and K2. The results show that kinetic energy losses decrease with nozzle diameter increments; from 80% for the smallest nozzle diameter (2 mm to 45% for nozzle diameters larger than 5.1 mm, and from 80% for the smallest nozzle diameter (2 mm to 34.7% for nozzle diameters larger than 6.8 mm, at 138 kPa and 69 kPa working pressures, respectively. The results from the model compared well with field observations. The calibrated model has reproduced accurately the water distribution pattern in calm (r=0.98 and high windy conditions (r=0.76. A new relationship was found between the corrector parameters (K1’ and K2’ and the wind speed. As a consequence, model simulation will be possible for untested meteorological conditions.

  17. Distribution patterns of macrofaunal species diversity in subtidal soft sediments: biodiversity-productivity relationships from the MacroBen database

    NARCIS (Netherlands)

    Escaravage, V.L.; Herman, P.M.J.; Merckx, B.; Bodarska-Kowalczuk, M.W.; Amouroux, J.M.; Degraer, S.; Grémare, A.; Heip, C.H.R.; Hummel, H.; Karakassis, I.; Labrune, C.; Willems, W.

    2009-01-01

    We analyzed patterns of species diversity in a compiled data set covering the European coast (from Norway to Crete) that was made available in the framework of the MarBEF European Network of Excellence. The focus was on the distribution patterns of species diversity over large areas across Europe.

  18. Positive and negative feedbacks and free-scale pattern distribution in rural-population dynamics.

    Directory of Open Access Journals (Sweden)

    Concepción L Alados

    Full Text Available Depopulation of rural areas is a widespread phenomenon that has occurred in most industrialized countries, and has contributed significantly to a reduction in the productivity of agro-ecological resources. In this study, we identified the main trends in the dynamics of rural populations in the Central Pyrenees in the 20th C and early 21st C, and used density independent and density dependent models and identified the main factors that have influenced the dynamics. In addition, we investigated the change in the power law distribution of population size in those periods. Populations exhibited density-dependent positive feedback between 1960 and 2010, and a long-term positive correlation between agricultural activity and population size, which has resulted in a free-scale population distribution that has been disrupted by the collapse of the traditional agricultural society and by emigration to the industrialized cities. We concluded that complex socio-ecological systems that have strong feedback mechanisms can contribute to disruptive population collapses, which can be identified by changes in the pattern of population distribution.

  19. Links of the significant wave height distribution in the Mediterranean sea with the Northern Hemisphere teleconnection patterns

    Directory of Open Access Journals (Sweden)

    P. Lionello

    2008-06-01

    Full Text Available This study analyzes the link between the SWH (Significant Wave Height distribution in the Mediterranean Sea during the second half of the 20th century and the Northern Hemisphere SLP (Sea Level Pressure teleconnection patterns.

    The SWH distribution is computed using the WAM (WAve Model forced by the surface wind fields provided by the ERA-40 reanalysis for the period 1958–2001. The time series of mid-latitude teleconnection patterns are downloaded from the NOAA web site. This study shows that several mid-latitude patterns are linked to the SWH field in the Mediterranean, especially in its western part during the cold season: East Atlantic Pattern (EA, Scandinavian Pattern (SCA, North Atlantic Oscillation (NAO, East Atlantic/West Russia Pattern (EA/WR and East Pacific/ North Pacific Pattern (EP/NP. Though the East Atlantic pattern exerts the largest influence, it is not sufficient to characterize the dominant variability. NAO, though relevant, has an effect smaller than EA and comparable to other patterns. Some link results from possibly spurious structures. Patterns which have a very different global structure are associated to similar spatial features of the wave variability in the Mediterranean Sea. These two problems are, admittedly, shortcomings of this analysis, which shows the complexity of the response of the Mediterranean SWH to global scale SLP teleconnection patterns.

  20. Distribution Pattern of Earthquake-induced Landslides Triggered by the 12 May 2008 Wenchuan Earthquake

    Science.gov (United States)

    van Westen, Cees; Gorum, Tolga; Fan, Xuanmei; Qiu Huang, Run; Xu, Qiang; Tang, Chuang

    2010-05-01

    The catastrophic 12 May 2008 Wenchuan earthquake (Mw=7.9) occurred on the NE-SW trending Longmenshan fault zone at the eastern margin of the Tibetan Plateau, just west of the Sichuan basin, China. This extraordinary event triggered a large number of landslides, rock avalanches and debris flows, causing fatalities of more than 80,000, more than 374,176 people injured and serious economic loss. Our work shows the preliminary results of an extensive study on the mapping of the distribution of landslides triggered by the earthquake. An extensive landslide interpretation was carried out using a large set of optical high resolution satellite images (e.g. ASTER, ALOS, Cartosat-1, SPOT-5 and IKONOS) as well as air photos for both the pre- and post-earthquake situation. Landslide scarps were mapped as points using multi-temporal visual image interpretation taking into account shape, tone, texture, pattern, elevation and ridge and valley orientation. Nearly 60,000 individual landslide scarps were mapped. The landslide distribution map was compared with the inventory map that was prepared directly after the earthquake, which contains about 11,000 individual landslide points, through the calculation of normalized landslide isopleths maps. Remarkable differences were observed, as the earlier inventory mapping didn't consider the pre-earthquake situation and did not consider all individual landslides. As part of the landslide inventory, all landslides were identified that had blocked the drainage and had formed landslide dams. Detailed event-based landslide dam inventory map was prepared to show the landslide dam distribution and characteristics. The landslide distribution was compared with a number of aspects, such as the seismic parameters (distance to epicenter, distance to fault rupture, co-seismic fault geometry and co-seismic slip rate distribution), and geology. The most remarkable correlation found was with the co-seismic slip rate distribution and the fault geometry

  1. Investigating vertical distribution patterns of lower tropospheric PM2.5 using unmanned aerial vehicle measurements

    Science.gov (United States)

    Li, Xiao-Bing; Wang, Dong-Sheng; Lu, Qing-Chang; Peng, Zhong-Ren; Wang, Zhan-Yong

    2018-01-01

    A lightweight unmanned aerial vehicle (UAV) was outfitted with miniaturized sensors to investigate the vertical distribution patterns and sources of fine aerosol particles (PM2.5) within the 1 000 m lower troposphere. A total of 16 UAV flights were conducted in the Yangtze River Delta (YRD) region, China, from the summer to winter in 2014. The associated ground-level measurements from two environmental monitoring stations were also used for background analysis. The results show that ground-level PM2.5 concentrations demonstrated a decreasing trend from Feb. to Jul. and an increasing trend from Aug. to Jan. (the following year). Higher PM2.5 concentrations during the day were mainly observed in the morning (Local Time, LT 05-09) in the spring and summer. However, higher PM2.5 concentrations occurred mainly in the late afternoon and evening (LT 16-20) in the autumn and winter, excluding severe haze pollution days when higher PM2.5 concentrations were also observed during the morning periods. Lower tropospheric PM2.5 concentrations exhibited similar diurnal vertical distribution patterns from the summer to winter. The PM2.5 concentrations decreased with height in the morning, with significantly large vertical gradients from the summer to winter. By contrast, the aerosol particles were well mixed with PM2.5 concentrations of lower than 35 μg ṡm-3 in the early afternoon (LT 12-16) due to sufficient expansions of the planetary boundary layer. The mean vertical PM2.5 concentrations within the 1 000 m lower troposphere in the morning were much larger in the winter (∼87.5 μg ṡm-3) than in the summer and autumn (∼20 μg ṡm-3). However, subtle differences of ∼11 μg ṡm-3 in the mean vertical PM2.5 concentrations were observed in the early afternoon from the summer to winter. The vertical distribution patterns of black carbon and its relationships with PM2.5 indicated that the lower tropospheric aerosol particles might be mainly derived from fossil

  2. Wind-driven Snow Distribution Patterns Over an Antarctic Ice Floe

    Science.gov (United States)

    Trujillo, E.; Leonard, K. C.; Maksym, T.; Lehning, M.

    2015-12-01

    Sea ice, snow and atmosphere interactions are major drivers of the spatial distribution of snow over sea ice in polar regions. Here, we combine measurements of the wind flow, atmospheric conditions and blowing snow at two locations on an Antarctic sea ice floe, with terrestrial laser scanning to characterize a blowing snow storm and its influence on the spatial patterns of snow distribution at resolutions of 1-10 cm over an area of 100 m x 100 m. The datasets were obtained during the SIPEX II (Sea Ice Physics and Ecosystem eXperiment II) research voyage to East Antarctica (September-November 2012). The pre-storm surface (2012-10-20) exhibits multi-directional elongated snow dunes behind aerodynamic obstacles likely formed during previous snowstorms. The post-storm surface (2012-10-23) exhibits clear new deposition dunes elongated along the predominant wind direction. The new deposition areas amount to 38% of the total surveyed area. Patterns of erosion are less evident but cover a larger portion of the area. This results in a total volume of change near zero with a mean elevation difference of 0.02 m indicating that net erosion or deposition from snowfall was small despite of large mass relocation. After the storm, the statistical distributions of elevation and the 2D correlation functions remain similar to those of the pre-storm surface. The pre- and post-storm surfaces also exhibit power-law relationships in the power spectrum with little change between pre- and post-storm slopes. These observations suggest that despite the significant change observed in the snow surface patterns, the change does not translate into significant changes in the spatial statistical and scaling properties of the surface morphology. Such an observation is important for sea-ice model representations of the sub-pixel variability of sea ice surfaces, particularly between snowstorm events, although more datasets will be required to extend these results to a wider range of sea ice surface

  3. Computational Fluid Dynamics Study on the Influence of Airflow Patterns on Carbon Dioxide Distribution in a Scaled Livestock Building

    DEFF Research Database (Denmark)

    Rong, Li; Nielsen, Peter V.; Tong, Guohong

    2008-01-01

    has been applied to simulate the contaminant distribution. Experiments of tracer gas concentration distribution in the chamber are performed at Air Physic Lab of Aarhus University to validate CFD software. Simulation results and measurements show that ventilation rates and airflow patterns have...

  4. Woody plant encroachment into grasslands: spatial patterns of functional group distribution and community development.

    Science.gov (United States)

    Liu, Feng; Archer, Steven R; Gelwick, Frances; Bai, Edith; Boutton, Thomas W; Wu, Xinyuan Ben

    2013-01-01

    Woody plant encroachment into grasslands has been globally widespread. The woody species invading grasslands represent a variety of contrasting plant functional groups and growth forms. Are some woody plant functional types (PFTs) better suited to invade grasslands than others? To what extent do local patterns of distribution and abundance of woody PFTs invading grasslands reflect intrinsic topoedaphic properties versus plant-induced changes in soil properties? We addressed these questions in the Southern Great Plains, United States at a subtropical grassland known to have been encroached upon by woody species over the past 50-100 years. A total of 20 woody species (9 tree-statured; 11 shrub-statured) were encountered along a transect extending from an upland into a playa basin. About half of the encroaching woody plants were potential N2-fixers (55% of species), but they contributed only 7% to 16 % of the total basal area. Most species and the PFTs they represent were ubiquitously distributed along the topoedaphic gradient, but with varying abundances. Overstory-understory comparisons suggest that while future species composition of these woody communities is likely to change, PFT composition is not. Canonical correspondence analysis (CCA) ordination and variance partitioning (Partial CCA) indicated that woody species and PFT composition in developing woody communities was primarily influenced by intrinsic landscape location variables (e.g., soil texture) and secondarily by plant-induced changes in soil organic carbon and total nitrogen content. The ubiquitous distribution of species and PFTs suggests that woody plants are generally well-suited to a broad range of grassland topoedaphic settings. However, here we only examined categorical and non-quantitative functional traits. Although intrinsic soil properties exerted more control over the floristics of grassland-to-woodland succession did plant modifications of soil carbon and nitrogen concentrations, the latter

  5. A distribution pattern of cadmium, gadolinium and samarium in Phaseolus vulgaris (L) plants as assessed by dynamic neutron radiography

    Science.gov (United States)

    Kőrösi, Ferenc; Balaskó, Márton; Sváb, Erzsébet

    1999-11-01

    The qualitative and semi-quantitative distributions, presumably apoplast transport patterns for the Gd, Sm and Cd were investigated in the primordial leaf tissues of the bean using dynamic neutron radiography. According to the applied 3D, 2D images and the pixel count distribution histograms of the considered gray levels, peculiar distribution patterns were postulated for the elements. Main and lateral vascular systems for Gd, the cell walls as well as intercellular spaces for Sm and the main leaf vein for Cd assumed to be the apoplast transport spaces and volumes.

  6. Movement Behaviour of the Carabid Beetle Pterostichus melanarius in Crops and a Habitat Interface Explains Patterns of Population Redistribution in the Field

    NARCIS (Netherlands)

    Allema, B.; Werf, van der W.; Lenteren, van J.C.; Hemerik, L.; Rossing, W.A.H.

    2014-01-01

    Animals may respond to habitat quality and habitat edges and these responses may affect their distribution between habitats. We studied the movement behaviour of a ground-dwelling generalist predator, the carabid beetle Pterostichus melanarius (Illiger). We performed a mark-recapture experiment in

  7. Species distributions and climate change:current patterns and future scenarios for biodiversity

    DEFF Research Database (Denmark)

    Hof, Christian

    extinction, one might assume that most species may also be able to successfully cope with contemporary climate change. However, current ecosystems are heavily modified by humans. Among other factors, habitat destruction and fragmentation caused by anthropogenic land-use changes negatively affect species...... orders. The ability to successfully track climatic changes depends on dispersal, which is in turn influenced by ecological adaptations, such as the affiliation with a certain habitat type. A common hypothesis is that species adapted to less persistent habitats have evolved stronger dispersal abilities....... Two studies of my thesis provide evidence for this hypothesis: (1) geographical distributions of dragonflies adapted to less persistent habitats show higher degrees of equilibrium with climatic conditions; (2) spatial patterns of European freshwater species richness and turnover differ strongly among...

  8. Effects of different shoe-lacing patterns on dorsal pressure distribution during running and perceived comfort.

    Science.gov (United States)

    Hagen, Marco; Hömme, Ann-Kathrin; Umlauf, Tim; Hennig, Ewald M

    2010-07-01

    The purpose of this study was to investigate the effects of four lacing patterns (one regular, one tight, and two seven-eyelet lacings) on dorsal foot pressures during running and the perception of comfort and stability with 14 male rearfoot runners. By using a pressure insole, peak dorsal pressures were measured under the shoe's tongue. Highest peak pressures were found above the talus, the navicular bone, and the first ray. Seven-eyelet lacings showed a significant enhancement of perceived stability without differences in perceived comfort compared with a regular six-eyelet technique. Reduction of pressure on the talus, the navicular bone, and the extensor tendons is related to better comfort. With individually chosen special seven-eyelet lacings runners can improve foot-shoe coupling without increasing peak dorsal pressures on the tarsus. Knowledge of the location of the dorsal pressure distribution is useful for new tongue and lacing constructions to improve comfort in running shoes while maintaining stability.

  9. Contamination and sample mix-up can best explain some patterns of mtDNA instabilities in buccal cells and oral squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Salas Antonio

    2009-04-01

    Full Text Available Abstract The study of somatic DNA instabilities constitutes a debatable topic because different causes can lead to seeming DNA alteration patterns between different cells or tissues from the same individual. Carcinogenesis or the action of a particular toxic could generate such patterns, and this is in fact the leitmotif of a number of studies on mitochondrial DNA (mtDNA instability. Patterns of seeming instabilities could also arise from technical errors at any stage of the analysis (DNA extraction, amplification, mutation screening/sequencing, and documentation. Specifically, inadvertent DNA contamination or sample mixing would yield mosaic variation that could be erroneously interpreted as real mutation differences (instabilities between tissues from the same individual. From the very beginning, mtDNA studies comparing cancerous to non-cancerous tissues have suffered from such mosaic results. We demonstrate here that the phylogenetic linkage of whole arrays of mtDNA mutations provides strong evidence of artificial recombination in previous studies on buccal cells and oral squamous cell carcinoma.

  10. Geospatial analysis and distribution patterns of home nursing care in a metropolitan area - a large-scale analysis.

    Science.gov (United States)

    Bauer, Jan; Reinhard, Julia; Boll, Michael; Groneberg, David

    2017-01-01

    This study focuses on home nursing care distribution in an urban setting in Germany. A shortage of nursing care workforce is present in Germany. A geospatial analysis was performed to examine distribution patterns at the district level in Frankfurt, Germany (n = 46 districts) and factors were analysed influencing the location choice of home nursing care providers (n = 151). Furthermore, within the analysis we focused on the population aged over 65 years to model the demand for nursing care. The analysis revealed a tendency of home nursing care providers to be located near the city centre (centripetal distribution pattern). However, the demand for care showed more inconsistent patterns. Still, a centripetal distribution pattern of demand could be stated. Compared with the control groups (e.g. acute hospitals and pharmacies) similar geographical distribution patterns were present. However, the location of home nursing care providers was less influenced by demand compared with the control groups. The supply of nursing care was unevenly distributed in this metropolitan setting, but still matched the demand for nursing care. Due to the rapidly changing health care environments policy, regulations must be (re-)evaluated critically to improve the management and delivery of nursing care provision. © 2016 John Wiley & Sons Ltd.

  11. Large-scale spatial distribution patterns of echinoderms in nearshore rocky habitats.

    Directory of Open Access Journals (Sweden)

    Katrin Iken

    Full Text Available This study examined echinoderm assemblages from nearshore rocky habitats for large-scale distribution patterns with specific emphasis on identifying latitudinal trends and large regional hotspots. Echinoderms were sampled from 76 globally-distributed sites within 12 ecoregions, following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org. Sample-based species richness was overall low (2 cm in 1 m(2 quadrats was highest in the Caribbean ecoregions and echinoids dominated these assemblages with an average of 5 ind m(-2. In contrast, intertidal echinoderm assemblages collected from clearings of 0.0625 m(2 quadrats had the highest abundance and richness in the Northeast Pacific ecoregions where asteroids and holothurians dominated with an average of 14 ind 0.0625 m(-2. Distinct latitudinal trends existed for abundance and richness in intertidal assemblages with declines from peaks at high northern latitudes. No latitudinal trends were found for subtidal echinoderm assemblages with either sampling technique. Latitudinal gradients appear to be superseded by regional diversity hotspots. In these hotspots echinoderm assemblages may be driven by local and regional processes, such as overall productivity and evolutionary history. We also tested a set of 14 environmental variables (six natural and eight anthropogenic as potential drivers of echinoderm assemblages by ecoregions. The natural variables of salinity, sea-surface temperature, chlorophyll a, and primary productivity were strongly correlated with echinoderm assemblages; the anthropogenic variables of inorganic pollution and nutrient contamination also contributed to correlations. Our results indicate that nearshore echinoderm assemblages appear to be shaped by a network of environmental and ecological processes, and by the differing responses of various echinoderm taxa, making generalizations about the patterns of nearshore rocky habitat echinoderm

  12. Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope.

    Directory of Open Access Journals (Sweden)

    Juliana Couto Di Tullio

    Full Text Available Temporal and spatial patterns of cetacean diversity and distribution were investigated through eight ship-based surveys carried out during spring and autumn between 2009 and 2014 on the outer continental shelf (~150m and slope (1500m off southeastern and southern Brazil (~23°S to ~34°S. The survey area was divided into southeast and south areas according to their oceanographic characteristics. Twenty-one species were observed in 503 sightings. The overall number of species was similar between the two areas, though it was higher in the spring in the south area. Five species were dominant and diversity varied more seasonally than spatially. ANOVA and kernel analyses showed that overall cetacean densities were higher in spring compared to autumn. Physeter macrocephalus, the most frequent species, concentrated throughout the south area at depths over 1000m in both seasons. Despite the overlapped occurrence at a broader scale, small delphinids presented latitudinal and in-offshore gradients as well as seasonal variation in distribution patterns, which could indicate habitat partitioning between some species. Delphinus delphis was only recorded in the south and its density decreased in areas where the presence of Stenella frontalis increased, mainly beyond the 250m isobath. Densities of S. longirostris and S. attenuata increased in lower latitudes and beyond the shelf break. The large delphinids Tursiops truncatus and Globicephala melas formed mixed groups in many occasions and were observed along the study area around depths of 500m. Grampus griseus was twice as frequent in the south area and densities increased in waters deeper than 600m. As expected, densities of both small and large migratory whales were higher during spring, over the continental slope, in the southeast area. The results presented here provided strong evidence on the importance of the outer continental shelf and slope to a diverse community of cetaceans occurring in the

  13. Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope.

    Science.gov (United States)

    Di Tullio, Juliana Couto; Gandra, Tiago B R; Zerbini, Alexandre N; Secchi, Eduardo R

    2016-01-01

    Temporal and spatial patterns of cetacean diversity and distribution were investigated through eight ship-based surveys carried out during spring and autumn between 2009 and 2014 on the outer continental shelf (~150m) and slope (1500m) off southeastern and southern Brazil (~23°S to ~34°S). The survey area was divided into southeast and south areas according to their oceanographic characteristics. Twenty-one species were observed in 503 sightings. The overall number of species was similar between the two areas, though it was higher in the spring in the south area. Five species were dominant and diversity varied more seasonally than spatially. ANOVA and kernel analyses showed that overall cetacean densities were higher in spring compared to autumn. Physeter macrocephalus, the most frequent species, concentrated throughout the south area at depths over 1000m in both seasons. Despite the overlapped occurrence at a broader scale, small delphinids presented latitudinal and in-offshore gradients as well as seasonal variation in distribution patterns, which could indicate habitat partitioning between some species. Delphinus delphis was only recorded in the south and its density decreased in areas where the presence of Stenella frontalis increased, mainly beyond the 250m isobath. Densities of S. longirostris and S. attenuata increased in lower latitudes and beyond the shelf break. The large delphinids Tursiops truncatus and Globicephala melas formed mixed groups in many occasions and were observed along the study area around depths of 500m. Grampus griseus was twice as frequent in the south area and densities increased in waters deeper than 600m. As expected, densities of both small and large migratory whales were higher during spring, over the continental slope, in the southeast area. The results presented here provided strong evidence on the importance of the outer continental shelf and slope to a diverse community of cetaceans occurring in the subtropical Southwestern

  14. Large-scale spatial distribution patterns of echinoderms in nearshore rocky habitats.

    Science.gov (United States)

    Iken, Katrin; Konar, Brenda; Benedetti-Cecchi, Lisandro; Cruz-Motta, Juan José; Knowlton, Ann; Pohle, Gerhard; Mead, Angela; Miloslavich, Patricia; Wong, Melisa; Trott, Thomas; Mieszkowska, Nova; Riosmena-Rodriguez, Rafael; Airoldi, Laura; Kimani, Edward; Shirayama, Yoshihisa; Fraschetti, Simonetta; Ortiz-Touzet, Manuel; Silva, Angelica

    2010-11-05

    This study examined echinoderm assemblages from nearshore rocky habitats for large-scale distribution patterns with specific emphasis on identifying latitudinal trends and large regional hotspots. Echinoderms were sampled from 76 globally-distributed sites within 12 ecoregions, following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). Sample-based species richness was overall low (species per site), with a total of 32 asteroid, 18 echinoid, 21 ophiuroid, and 15 holothuroid species. Abundance and species richness in intertidal assemblages sampled with visual methods (organisms >2 cm in 1 m(2) quadrats) was highest in the Caribbean ecoregions and echinoids dominated these assemblages with an average of 5 ind m(-2). In contrast, intertidal echinoderm assemblages collected from clearings of 0.0625 m(2) quadrats had the highest abundance and richness in the Northeast Pacific ecoregions where asteroids and holothurians dominated with an average of 14 ind 0.0625 m(-2). Distinct latitudinal trends existed for abundance and richness in intertidal assemblages with declines from peaks at high northern latitudes. No latitudinal trends were found for subtidal echinoderm assemblages with either sampling technique. Latitudinal gradients appear to be superseded by regional diversity hotspots. In these hotspots echinoderm assemblages may be driven by local and regional processes, such as overall productivity and evolutionary history. We also tested a set of 14 environmental variables (six natural and eight anthropogenic) as potential drivers of echinoderm assemblages by ecoregions. The natural variables of salinity, sea-surface temperature, chlorophyll a, and primary productivity were strongly correlated with echinoderm assemblages; the anthropogenic variables of inorganic pollution and nutrient contamination also contributed to correlations. Our results indicate that nearshore echinoderm assemblages appear to be shaped by a

  15. Lifetime earnings patterns, the distribution of future Social Security benefits, and the impact of pension reform.

    Science.gov (United States)

    Bosworth, B; Burtless, G; Steuerle, E

    2000-01-01

    In order to assess the effect of Social Security reform on current and future workers, it is essential to accurately characterize the initial situations of representative workers affected by reform. For the purpose of analyzing typical reforms, the most important characteristic of a worker is the level and pattern of his or her preretirement earnings. Under the current system, pensions are determined largely by the level of the workers' earnings averaged over their work life. However, several reform proposals would create individual retirement accounts for which the pension would depend on the investment accumulation within the account. Thus, the pension would also depend on the timing of the contributions into the account and hence on the exact shape of the worker's lifetime earnings profile. Most analysis of the distributional impact of reform has focused, however, on calculating benefit changes among a handful of hypothetical workers whose relative earnings are constant over their work life. The earnings levels are not necessarily chosen to represent the situations of workers who have typical or truly representative earnings patterns. Consequently, the results of such analysis can be misleading, especially if reform involves introducing a fundamentally new kind of pension formula. This article presents two broad approaches to creating representative earnings profiles for policy evaluation. First, we use standard econometric methods to predict future earnings for a representative sample of workers drawn from the Survey of Income and Program Participation (SIPP). Our statistical estimates are based on a simple representation of typical career earnings paths and a fixed-effect statistical specification. Because our estimation file contains information on each worker's annual earnings from 1951 through 1996 as reported in the Social Security Administration's earnings files, we have a record (though an incomplete one) of the actual earnings that will be used to

  16. Cadmium and polychlorinated biphenyls: Different distribution pattern in North Sea Benthic biota

    Science.gov (United States)

    Everaarts, J. M.; Otter, E.; Fischer, C. V.

    Whole-body concentrations of cadmium in the shrimp Crangon allmanni and the starfish Asterias rubens were significantly higher in specimens collected from areas north and northeast of the Dogger Bank than in other areas of the North Sea studied. In the brown shrimp Crangon crangon, whose distribution is restricted to the estuarine and coastal zone, the cadmium concentration was found to be significantly lower than in C. allmanni and did not vary with sampling site. The cadmium concentrations in shrimp increased from the estuarine area (including the Dutch Wadden Sea) to the coastal zone and Southern Bight of the North Sea and again to the open central North Sea (Dogger Bank). Concentrations of the total of 50 polychlorinated biphenyl congeners ( Σ50-CB) were higher in Crangon crangon and Asterias rubens occurring in the coastal zone of the Southern Bight than in specimens of the central and northern part of the Dutch continental shelf. The Σ50-CB concentration in the shrimp Crangon allmanni was considerably lower than in the closely related species C. crangon. Thus, cadmium and PCBs showed different distribution patterns in North Sea benthic invertebrates: highest concentrations of Σ50-CB were restricted to estuarine and coastal areas and highest concentrations of cadmium were found in the open sea (central North Sea, north of the Dogger Bank).

  17. Controls on morphological variability and role of stream power distribution pattern, Yamuna River, western India

    Science.gov (United States)

    Bawa, Nupur; Jain, Vikrant; Shekhar, Shashank; Kumar, Niraj; Jyani, Vikas

    2014-12-01

    Understanding the controls on the morphological variability of river systems constitutes one of the fundamental questions in geomorphic investigation. Channel morphology is an important indicator of river processes and is of significance for mapping the hydrology-ecologic connectivity in a river system and for predicting the future trajectory of river health in response to external forcings. This paper documents the spatial morphological variability and its natural and anthropogenic controls for the Yamuna River, a major tributary of the Ganga River, India. The Yamuna River runs through a major urban centre i.e. Delhi National Capital Region. The Yamuna River was divided into eight geomorphically distinct reaches on the basis of the assemblages of geomorphic units and the association of landscape, valley and floodplain settings. The morphological variability was analysed through stream power distribution and sediment load data at various stations. Stream power distribution of the Yamuna River basin is characterised by a non-linear pattern that was used to distinguish (a) high energy ‘natural' upstream reaches, (b) ‘anthropogenically altered', low energy middle stream reaches, and (c) ‘rejuvenated' downstream reaches again with higher stream power. The relationship between stream power and channel morphology in these reaches was integrated with sediment load data to define the maximum flow efficiency (MFE) as the threshold for geomorphic transition. This analysis supports the continuity of river processes and the significance of a holistic, basin-scale approach rather than isolated local scale analysis in river studies.

  18. We'll meet again: revealing distributional and temporal patterns of social contact.

    Directory of Open Access Journals (Sweden)

    Thorsten Pachur

    Full Text Available What are the dynamics and regularities underlying social contact, and how can contact with the people in one's social network be predicted? In order to characterize distributional and temporal patterns underlying contact probability, we asked 40 participants to keep a diary of their social contacts for 100 consecutive days. Using a memory framework previously used to study environmental regularities, we predicted that the probability of future contact would follow in systematic ways from the frequency, recency, and spacing of previous contact. The distribution of contact probability across the members of a person's social network was highly skewed, following an exponential function. As predicted, it emerged that future contact scaled linearly with frequency of past contact, proportionally to a power function with recency of past contact, and differentially according to the spacing of past contact. These relations emerged across different contact media and irrespective of whether the participant initiated or received contact. We discuss how the identification of these regularities might inspire more realistic analyses of behavior in social networks (e.g., attitude formation, cooperation.

  19. Flea species infesting dogs in Spain: updated spatial and seasonal distribution patterns.

    Science.gov (United States)

    Gálvez, R; Montoya, A; Checa, R; Martín, O; Marino, V; Miró, G

    2017-03-01

    This entomological survey examines the spatial and seasonal distribution patterns of flea species infesting dogs in Spain. Bioclimatic zones covering broad climate and vegetation ranges were surveyed according to size. In a cross-sectional spatial survey carried out from late May 2013 to mid-July 2015, 1084 dogs from 42 different locations were examined. A total of 3032 fleas were collected and identified as belonging to the following species: Ctenocephalides felis (Siphonaptera: Pulicidae) (81.7%, 2476 fleas); Ctenocephalides canis (11.4%, 347 fleas); Pulex irritans (Siphonaptera: Pulicidae) (6.9%, 208 fleas), and Echidnophaga gallinacea (Siphonaptera: Pulicidae) (0.03%, one flea). Variables observed to have effects on flea abundance were animal weight, sex, length of hair and habitat. In the seasonal survey conducted from June 2014 to June 2015, 1014 fleas were collected from 239 dogs at 30 veterinary practices across Spain. Peaks in C. felis abundance were observed in early summer and late autumn, whereas high numbers of P. irritans and C. canis were recorded in autumn. Numbers of fleas detected in winter were low overall. Based on these findings, the present study updates the spatial and seasonal distributions of flea species in Spain and assesses the impacts of host and habitat variables on flea infestation. © 2016 The Royal Entomological Society.

  20. Distributional patterns of shallow-water polychaetes in the Magellan region: a zoogeographical and ecological synopsis

    Directory of Open Access Journals (Sweden)

    Américo Montiel San Martín

    2005-12-01

    Full Text Available The zoogeography of polychaete annelids was described for the Magellan region. This work considered information available from 19 expeditions carried out in the last 124 years of polychaete taxonomic research around the southernmost tip of the South American continental shelf. The polychaete fauna of the Magellan region comprised a total of 431 species belonging to 108 genera and 41 families. MDS and ANOSIM analyses showed the Magellan region to be divided into two subregions, one on the Pacific side of the tip of South America and one on the Atlantic side. These subregions showed a low percentage of “endemic species” ( 70% of the species recorded for the whole Magellan region showed a wide distribution range, and there were especially high affinities with Antarctic and Subantarctic areas. We suggest that the opening of the Straits of Magellan created a new pathway for enhanced exchange of faunal elements between the Pacific and the Atlantic. Transport of larvae via easterly directed currents of the West Wind Drift plays an important role in current distribution patterns of polychaete fauna around the tip of South America.

  1. Pan-Arctic aerosol number size distributions: seasonality and transport patterns

    Science.gov (United States)

    Freud, Eyal; Krejci, Radovan; Tunved, Peter; Leaitch, Richard; Nguyen, Quynh T.; Massling, Andreas; Skov, Henrik; Barrie, Leonard

    2017-07-01

    The Arctic environment has an amplified response to global climatic change. It is sensitive to human activities that mostly take place elsewhere. For this study, a multi-year set of observed aerosol number size distributions in the diameter range of 10 to 500 nm from five sites around the Arctic Ocean (Alert, Villum Research Station - Station Nord, Zeppelin, Tiksi and Barrow) was assembled and analysed.A cluster analysis of the aerosol number size distributions revealed four distinct distributions. Together with Lagrangian air parcel back-trajectories, they were used to link the observed aerosol number size distributions with a variety of transport regimes. This analysis yields insight into aerosol dynamics, transport and removal processes, on both an intra- and an inter-monthly scale. For instance, the relative occurrence of aerosol number size distributions that indicate new particle formation (NPF) event is near zero during the dark months, increases gradually to ˜ 40 % from spring to summer, and then collapses in autumn. Also, the likelihood of Arctic haze aerosols is minimal in summer and peaks in April at all sites.The residence time of accumulation-mode particles in the Arctic troposphere is typically long enough to allow tracking them back to their source regions. Air flow that passes at low altitude over central Siberia and western Russia is associated with relatively high concentrations of accumulation-mode particles (Nacc) at all five sites - often above 150 cm-3. There are also indications of air descending into the Arctic boundary layer after transport from lower latitudes.The analysis of the back-trajectories together with the meteorological fields along them indicates that the main driver of the Arctic annual cycle of Nacc, on the larger scale, is when atmospheric transport covers the source regions for these particles in the 10-day period preceding the observations in the Arctic. The scavenging of these particles by precipitation is shown to be

  2. Pattern of distribution of serotonergic fibers to the amygdala and extended amygdala in the rat.

    Science.gov (United States)

    Linley, Stephanie B; Olucha-Bordonau, Francisco; Vertes, Robert P

    2017-01-01

    As is well recognized, serotonergic (5-HT) fibers distribute widely throughout the forebrain, including the amygdala. Although a few reports have examined the 5-HT innervation of select nuclei of the amygdala in the rat, no previous report has described overall 5-HT projections to the amygdala in the rat. Using immunostaining for the serotonin transporter, SERT, we describe the complete pattern of distribution of 5-HT fibers to the amygdala (proper) and to the extended amygdala in the rat. Based on its ontogenetic origins, the amygdala was subdivided into two major parts, pallial and subpallial components, with the pallial component further divided into superficial and deep nuclei (Olucha-Bordonau et al. 2015). SERT + fibers were shown to distributed moderately to densely to the deep and cortical pallial nuclei, but, by contrast, lightly to the subpallial nuclei. Specifically, 1) of the deep pallial nuclei, the lateral, basolateral, and basomedial nuclei contained a very dense concentration of 5-HT fibers; 2) of the cortical pallial nuclei, the anterior cortical and amygdala-cortical transition zone rostrally and the posteromedial and posterolateral nuclei caudally contained a moderate concentration of 5-HT fibers; and 3) of the subpallial nuclei, the anterior nuclei and the rostral part of the medial (Me) nuclei contained a moderate concentration of 5-HT fibers, whereas caudal regions of Me as well as the central nuclei and the intercalated nuclei contained a sparse/light concentration of 5-HT fibers. With regard to the extended amygdala (primarily the bed nucleus of stria terminalis; BST), on the whole, the BST contained moderate numbers of 5-HT fibers, spread fairly uniformly throughout BST. The findings are discussed with respect to a critical serotonergic influence on the amygdala, particularly on the basal complex, and on the extended amygdala in the control of states of fear and anxiety. J. Comp. Neurol. 525:116-139, 2017. © 2016 Wiley Periodicals, Inc.

  3. Patterns of distribution and landscape connectivity of the stag beetle in a human-dominated landscape

    Directory of Open Access Journals (Sweden)

    Francesca Della Rocca

    2017-07-01

    Full Text Available Urbanisation and the spread of agriculture have resulted in high levels of forest loss, habitat fragmentation and degradation in many regions of the world. In Italy, the Po Plain is the most human-dominated landscape of the country and, after decades of exploitation, old-growth forests have been reduced to small and isolated patches, often threatened by invasive tree species such as the black locust (Robinia pseudoacacia. In these habitats, the occurrence of many forest-dependent species is related to the quality and availability of suitable areas, as well as the connectivity between the remaining forested patches. Thus, recently developed species distribution models have been applied, namely the Ensemble of Small Models (ESMs, to identify areas of occurrence for a rare and protected saproxylic beetle species, the stag beetle Lucanus cervus and the inverse of the resulting distribution maps as resistance maps have been used to estimate landscape connectivity for this species. Response curves suggested that the probability of the stag beetle occurrence increased with habitat diversity, grassland coverage and native forests, especially oak and mixed forests. The other forest coverage, such as those with black locust, beech, chestnut and black cherry, showed a unimodal relationship peaking approximately at 70%, 8%, 55% and 13% respectively. The stag beetle occurrence was unimodal related to distance to watercourses and distance to human settlements and negatively related to shrub-lands, croplands, sparse and dense human settlements. Landscape connectivity showed similar patterns, except for oak forest coverage, which showed a negative relationship to landscape connectivity. In conclusion, stag beetles can persist in a human dominated landscape only in the presence of forest patches, including those with black locust trees. It is also inferred that ESMs may be suitable for modelling rare species distributions and estimating landscape connectivity to

  4. Pattern and Distribution of Colorectal Cancer in Tanzania: A Retrospective Chart Audit at Two National Hospitals

    Directory of Open Access Journals (Sweden)

    Leonard K. Katalambula

    2016-01-01

    Full Text Available Background. Colorectal cancer (CRC is a growing public health concern with increasing rates in countries with previously known low incidence. This study determined pattern and distribution of CRC in Tanzania and identified hot spots in case distribution. Methods. A retrospective chart audit reviewed hospital registers and patient files from two national institutions. Descriptive statistics, Chi square (χ2 tests, and regression analyses were employed and augmented by data visualization to display risk variable differences. Results. CRC cases increased sixfold in the last decade in Tanzania. There was a 1.5% decrease in incidences levels of rectal cancer and 2% increase for colon cancer every year from 2005 to 2015. Nearly half of patients listed Dar es Salaam as their primary residence. CRC was equally distributed between males (50.06% and females (49.94%, although gender likelihood of diagnosis type (i.e., rectal or colon was significantly different (P=0.027. More than 60% of patients were between 40 and 69 years. Conclusions. Age (P=0.0183 and time (P=0.004 but not gender (P=0.0864 were significantly associated with rectal cancer in a retrospective study in Tanzania. Gender (P=0.0405, age (P=0.0015, and time (P=0.0075 were all significantly associated with colon cancer in this study. This retrospective study found that colon cancer is more prevalent among males at a relatively younger age than rectal cancer. Further, our study showed that although more patients were diagnosed with rectal cancer, the trend has shown that colon cancer is increasing at a faster rate.

  5. Explaining traffic patterns at on-ramp vicinity by a driver perception model in the framework of three-phase traffic theory

    Science.gov (United States)

    He, Shuyan; Guan, Wei; Song, Liying

    2010-02-01

    In traffic system, driving behaviors change with the surrounding traffic perceived by drivers, resulting in the complex spatio-temporal traffic patterns. Accordingly, in the majority of traffic models, vehicle accelerations are described by dynamic equations based on driving behavior, system dynamics and some underlying steady-state velocity-gap (bumper-to-bumper spacing) relation in order to guarantee the realistic human behavior. This paper proposes a deterministic car-following model based on a multi-branch fundamental diagram with each branch representing a particular category of driving style. Furthermore, an additional dynamic perception equation is introduced to reflect the driving style adaptation in response to the change in surrounding traffic situations. With simulation based on the proposed “driver perception model” (DP model), empirical findings of traffic breakdown and observed spatio-temporal patterns at on-ramp vicinity are reproduced. Furthermore, comparison results show the consistency between numerical simulation and the real traffic data of Beijing urban freeway.

  6. Intra-articular distribution pattern after ultrasound-guided injections in wrist joints of patients with rheumatoid arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Boesen, Mikael [Parker Institute, Frederiksberg Hospital, Nordre Fasanvej 57, 2000 Frederiksberg, Copenhagen (Denmark)], E-mail: parker@frh.regioh.dk; Jensen, Karl Erik [State Hospital, Department of Radiology, MRI Division, Copenhagen (Denmark)], E-mail: karl.erik.Jensen@rh.regionh.dk; Torp-Pedersen, Soren [Parker Institute, Frederiksberg Hospital, Nordre Fasanvej 57, 2000 Frederiksberg, Copenhagen (Denmark); Cimmino, Marco A. [Rheumatologic Clinic, Department of Internal Medicine, University of Genoa (Italy)], E-mail: cimmino@unige.it; Danneskiold-Samsoe, Bente; Bliddal, Henning [Parker Institute, Frederiksberg Hospital, Nordre Fasanvej 57, 2000 Frederiksberg, Copenhagen (Denmark)

    2009-02-15

    Objective: To investigate the distribution of an ultrasound-guided intra-articular (IA) injection in the wrist joint of patients with rheumatoid arthritis (RA). Methods: An ultrasound-guided IA drug injection into the wrist joint was performed in 17 patients with 1 ml methylprednisolone (40 mg/ml), 0.5 ml Lidocaine (5 mg/ml) and 0.15 ml gadolinium (Omniscan 0.5 mmol/ml). The drug solution was placed in the central proximal part of the wrist between the distal radius and the lunate bone. Coronal and axial MRI sequences were performed after the injection to visualize the distribution. Carpal distribution (radio-carpal, inter-carpal, and carpo-metacarpal) as well as radio-ulnar distribution was recorded. Full distribution in one compartment was given the value 1, partial distribution 0.5 and no distribution 0. A sum of the total distribution for all four compartments was calculated and correlated to the clinical parameters and the MRI OMERACT scores. Results: No uniform pattern was seen in the distribution of the contrast. Only two patients had full contrast distribution to all four compartments, and the mean distribution count for all patients was 2.4 (range 0.5-4). The distribution count correlated with the MRI OMERACT synovitis score (r = 0.60, p = 0.014), but not with the erosions, bonemarrow oedema scores or any clinical parameters. Conclusion: The distribution of contrast on MRI showed patient specific and random patterns after IA injections in active RA wrist joints. The degree of distribution increased with the MRI synovitis score, while no association was found with the erosion- and bonemarrow oedema score. These results indicate that a single injection into a standard injection site in the proximal part of the wrist cannot be assumed to distribute - and treat - the whole joint.

  7. Seasonality in cholera dynamics : a rainfall-driven model explains the wide range of patterns of an infectious disease in endemic areas

    Science.gov (United States)

    Baracchini, Theo; Pascual, Mercedes; King, Aaron A.; Bouma, Menno J.; Bertuzzo, Enrico; Rinaldo, Andrea

    2015-04-01

    An explanation for the spatial variability of seasonal cholera patterns has remained an unresolved problem in tropical medicine te{pascual_2002}. Previous studies addressing the role of climate drivers in disease dynamics have focused on interannual variability and modelled seasonality as given te{king_nature}. Explanations for seasonality have relied on complex environmental interactions that vary with spatial location (involving regional hydrological models te{bertuzzo_2012}, river discharge, sea surface temperature, and plankton blooms). Thus, no simple and unified theory based on local climate variables has been formulated te{emch_2008}, leaving our understanding of seasonal variations of cholera outbreaks in different regions of the world incomplete. Through the analysis of a unique historical dataset containing 50 years of monthly meteorological, demographic and epidemiological records, we propose a mechanistic, SIR-based stochastic model for the population dynamics of cholera driven by local rainfall and temperature that is able to capture the full range of seasonal patterns in this large estuarine region, which encompasses the variety of patterns worldwide. Parameter inference was implemented via new statistical methods that allow the computation of maximum-likelihood estimates for partially observed Markov processes through sequential Monte-Carlo te{ionides_2011}. Such a model may provide a unprecedented opportunity to gain insights on the conditions and factors responsible for endemicity around the globe, and therefore, to also revise our understanding of the ecology of Vibrio cholerae. Results indicate that the hydrological regime is a decisive driver determining the seasonal dynamics of cholera. It was found that rainfall and longer water residence times tend to buffer the propagation of the disease in wet regions due to a dilution effect, while also enhancing cholera incidence in dry regions. This indicates that overall water levels matter and appear

  8. Soil Respiration in Tibetan Alpine Grasslands: Belowground Biomass and Soil Moisture, but Not Soil Temperature, Best Explain the Large-Scale Patterns

    Science.gov (United States)

    Geng, Yan; Wang, Yonghui; Yang, Kuo; Wang, Shaopeng; Zeng, Hui; Baumann, Frank; Kuehn, Peter; Scholten, Thomas; He, Jin-Sheng

    2012-01-01

    The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC) stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs) studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows) along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1) belowground biomass (BGB) is most closely related to spatial variation in Rs due to high root biomass density, and (2) soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 µmol CO2 m−2 s−1, ranging from 0.39 to 12.88 µmol CO2 m−2 s−1, with average daily mean Rs of 2.01 and 5.49 µmol CO2 m−2 s−1 for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB), SOC, soil moisture (SM), and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80%) of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82%) of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale. PMID:22509373

  9. Soil respiration in Tibetan alpine grasslands: belowground biomass and soil moisture, but not soil temperature, best explain the large-scale patterns.

    Directory of Open Access Journals (Sweden)

    Yan Geng

    Full Text Available The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1 belowground biomass (BGB is most closely related to spatial variation in Rs due to high root biomass density, and (2 soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 µmol CO(2 m(-2 s(-1, ranging from 0.39 to 12.88 µmol CO(2 m(-2 s(-1, with average daily mean Rs of 2.01 and 5.49 µmol CO(2 m(-2 s(-1 for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB, SOC, soil moisture (SM, and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80% of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82% of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale.

  10. A new mode of DNA binding distinguishes Capicua from other HMG-box factors and explains its mutation patterns in cancer.

    Science.gov (United States)

    Forés, Marta; Simón-Carrasco, Lucía; Ajuria, Leiore; Samper, Núria; González-Crespo, Sergio; Drosten, Matthias; Barbacid, Mariano; Jiménez, Gerardo

    2017-03-01

    HMG-box proteins, including Sox/SRY (Sox) and TCF/LEF1 (TCF) family members, bind DNA via their HMG-box. This binding, however, is relatively weak and both Sox and TCF factors employ distinct mechanisms for enhancing their affinity and specificity for DNA. Here we report that Capicua (CIC), an HMG-box transcriptional repressor involved in Ras/MAPK signaling and cancer progression, employs an additional distinct mode of DNA binding that enables selective recognition of its targets. We find that, contrary to previous assumptions, the HMG-box of CIC does not bind DNA alone but instead requires a distant motif (referred to as C1) present at the C-terminus of all CIC proteins. The HMG-box and C1 domains are both necessary for binding specific TGAATGAA-like sites, do not function via dimerization, and are active in the absence of cofactors, suggesting that they form a bipartite structure for sequence-specific binding to DNA. We demonstrate that this binding mechanism operates throughout Drosophila development and in human cells, ensuring specific regulation of multiple CIC targets. It thus appears that HMG-box proteins generally depend on auxiliary DNA binding mechanisms for regulating their appropriate genomic targets, but that each sub-family has evolved unique strategies for this purpose. Finally, the key role of C1 in DNA binding also explains the fact that this domain is a hotspot for inactivating mutations in oligodendroglioma and other tumors, while being preserved in oncogenic CIC-DUX4 fusion chimeras associated to Ewing-like sarcomas.

  11. The disjunct pattern of the Neotropical harvestman Discocyrtus dilatatus (Gonyleptidae explained by climate-driven range shifts in the Quaternary: Paleodistributional and molecular evidence.

    Directory of Open Access Journals (Sweden)

    Julia Vergara

    Full Text Available The disjunct distribution of the harvestman Discocyrtus dilatatus (Opiliones, Gonyleptidae is used as a case study to test the hypothesis of a trans-Chaco Pleistocene paleobridge during range expansion stages. This would have temporarily connected humid regions ('Mesopotamia' in northeastern Argentina, and the 'Yungas' in the northwest, NWA in the subtropical and temperate South American lowlands. The present study combines two independent approaches: paleodistributional reconstruction, using the Species Distribution Modeling method MaxEnt and projection onto Quaternary paleoclimates (6 kya, 21 kya, 130 kya, and phylogeographic analyses based on the cytochrome oxidase subunit I molecular marker. Models predict a maximal shrinkage during the warm Last Interglacial (130 kya, and the rise of the hypothesized paleobridge in the Last Glacial Maximum (21 kya, revealing that cold-dry stages (not warm-humid ones, as supposed enabled the range expansion of this species. The disjunction was formed in the mid-Holocene (6 kya and is intensified under current conditions. The median-joining network shows that NWA haplotypes are peripherally related to different Mesopotamian lineages; haplotypes from Santa Fe and Córdoba Provinces consistently occupy central positions in the network. According to the dated phylogeny, Mesopotamia-NWA expansion events would have occurred in the last glacial period, in many cases closely associated to the Last Glacial Maximum, with most divergence events occurring shortly thereafter. Only two (out of nine NWA haplotypes are shared with Mesopotamian localities. A single, presumably relictual NWA haplotype was found to have diverged much earlier, suggesting an ancient expansion event not recoverable by the paleodistributional models. Different measures of sequence statistics, genetic diversity, population structure and history of demographic changes are provided. This research offers the first available evidence for the historical

  12. Germline methylation patterns determine the distribution of recombination events in the dog genome.

    Science.gov (United States)

    Berglund, Jonas; Quilez, Javier; Arndt, Peter F; Webster, Matthew T

    2014-12-19

    The positive-regulatory domain containing nine gene, PRDM9, which strongly associates with the location of recombination events in several vertebrates, is inferred to be inactive in the dog genome. Here, we address several questions regarding the control of recombination and its influence on genome evolution in dogs. First, we address whether the association between CpG islands (CGIs) and recombination hotspots is generated by lack of methylation, GC-biased gene conversion (gBGC), or both. Using a genome-wide dog single nucleotide polymorphism data set and comparisons of the dog genome with related species, we show that recombination-associated CGIs have low CpG mutation rates, and that CpG mutation rate is negatively correlated with recombination rate genome wide, indicating that nonmethylation attracts the recombination machinery. We next use a neighbor-dependent model of nucleotide substitution to disentangle the effects of CpG mutability and gBGC and analyze the effects that loss of PRDM9 has on these rates. We infer that methylation patterns have been stable during canid genome evolution, but that dog CGIs have experienced a drastic increase in substitution rate due to gBGC, consistent with increased levels of recombination in these regions. We also show that gBGC is likely to have generated many new CGIs in the dog genome, but these mostly occur away from genes, whereas the number of CGIs in gene promoter regions has not increased greatly in recent evolutionary history. Recombination has a major impact on the distribution of CGIs that are detected in the dog genome due to the interaction between methylation and gBGC. The results indicate that germline methylation patterns are the main determinant of recombination rates in the absence of PRDM9. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  13. The advertisement call, color patterns and distribution of Ischnocnema izecksohni (Caramaschi and Kisteumacher, 1989 (Anura, Brachycephalidae

    Directory of Open Access Journals (Sweden)

    Pedro P. G. Taucce

    2012-01-01

    Full Text Available Ischnocnema izecksohni inhabits the gallery forests from the Quadrilátero Ferrífero, Southern Espinhaço range, state of Minas Gerais, southeastern Brazil, and it is considered endemic to this region. Its closest related species is I. nasuta according to the original description. We describe the advertisement call of I. izecksohni based on specimens recorded and collected at the municipality of Nova Lima, state of Minas Gerais, distant about 10 km straight line from its type locality. The advertisement call consists of a group of notes emitted sporadically without a regular interval between the calls. Call duration (n = 36 calls in four individuals ranged from 1.03 to 1.85 s (= 1.52 ± 0.21 s and the call rise time from 0.66 to 1.52 s (= 1.16 ± 0.25 s, with 34-57 notes per call (= 47.42 ± 6.03. Peak frequency ranged from 2250 to 2625 Hz, the dominant frequency from 1317.8 to 3128.0 Hz and interval between notes from 22.00 to 41.00 ms (= 28.63 ± 0.03 ms. From the examination of herpetological collections, morphological and bioacoustical data we extended the species known distribution ca. 200 km eastward, to ten new localities, all of them outside the Quadrilátero Ferrífero region, at the Mantiqueira mountain range. We analyzed color patterns and we find some dorsal patterns not described at the original description of I. izecksohni. We also make some comments concerning the taxonomic status of I. izecksohni and I. nasuta.

  14. The geographical pattern of distribution of the genus Tityobuthus Pocock, 1890, a typical Ananterinae element endemic to Madagascar (Scorpiones: Buthidae).

    Science.gov (United States)

    Lourenço, Wilson R; Waeber, Patrick O; Wilmé, Lucienne

    2016-01-01

    New comments are proposed for the Ananterinae (sensu Pocock) or the 'Ananteris Group'. The worldwide pattern of distribution of the elements associated with the Ananterinae, as well as aspects of their ecology, is discussed. The biogeographic patterns presented by extant and fossil elements of this group confirm not only the characteristics of a lineage representing a typical Gondwanian distribution, but correspond also to older Pangean patterns. One new species is described in the genus Tityobuthus Pocock. This new species is also a possible endemic element to the Island of Nosy-Be or at least to the Sambirano region. Generally, the Madagascar pattern of Tityobuthus is following the Neogrosphus rule, showing typical high species richness with low dispersal when the ancestral population had a large niche breadth. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  15. Pattern and distribution of colonic diverticulosis: analysis of 2877 barium enemas in Thailand.

    Science.gov (United States)

    Lohsiriwat, Varut; Suthikeeree, Wanwarang

    2013-12-14

    To determine the pattern and distribution of colonic diverticulosis in Thai adults. A review of the computerized radiology database for double contrast barium enema (DCBE) in Thai adults was performed at the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. Incomplete studies and DCBE examinations performed in non-Thai individuals were excluded. The pattern and distribution of colonic diverticulosis detected during DCBE studies from June 2009 to October 2011 were determined. The occurrence of solitary cecal diverticulum, rectal diverticulum and giant diverticulum were reported. Factors influencing the presence of colonic diverticulosis were evaluated. A total of 2877 suitable DCBE examinations were retrospectively reviewed. The mean age of patients was 59.8 ± 14.7 years. Of these patients, 1778 (61.8%) were female and 700 (24.3%) were asymptomatic. Colonic diverticulosis was identified in 820 patients (28.5%). Right-sided diverticulosis (641 cases; 22.3%) was more frequently reported than left-sided diverticulosis (383 cases; 13.3%). Pancolonic diverticulosis was found in 98 cases (3.4%). The occurrence of solitary cecal diverticulum, rectal diverticulum and giant diverticulum were 1.5% (42 cases), 0.4% (12 cases), and 0.03% (1 case), respectively. There was no significant difference in the overall occurrence of colonic diverticulosis between male and female patients (28.3% vs 28.6%, P = 0.85). DCBE examinations performed in patients with some gastrointestinal symptoms revealed the frequent occurrence of colonic diverticulosis compared with those performed in asymptomatic individuals (29.5% vs 25.3%, P = 0.03). Change in bowel habit was strongly associated with the presence of diverticulosis (a relative risk of 1.39; P = 0.005). The presence of diverticulosis was not correlated with age in symptomatic patients or asymptomatic individuals (P > 0.05). Colonic diverticulosis was identified in 28.5% of DCBE examinations in Thai adults. There

  16. Foliar Nutrient Distribution Patterns in Sympatric Maple Species Reflect Contrasting Sensitivity to Excess Manganese.

    Directory of Open Access Journals (Sweden)

    Denise R Fernando

    Full Text Available Sugar maple and red maple are closely-related co-occurring tree species significant to the North American forest biome. Plant abiotic stress effects including nutritional imbalance and manganese (Mn toxicity are well documented within this system, and are implicated in enhanced susceptibility to biotic stresses such as insect attack. Both tree species are known to overaccumulate foliar manganese (Mn when growing on unbuffered acidified soils, however, sugar maple is Mn-sensitive, while red maple is not. Currently there is no knowledge about the cellular sequestration of Mn and other nutrients in these two species. Here, electron-probe x-ray microanalysis was employed to examine cellular and sub-cellular deposition of excessively accumulated foliar Mn and other mineral nutrients in vivo. For both species, excess foliar Mn was deposited in symplastic cellular compartments. There were striking between-species differences in Mn, magnesium (Mg, sulphur (S and calcium (Ca distribution patterns. Unusually, Mn was highly co-localised with Mg in mesophyll cells of red maple only. The known sensitivity of sugar maple to excess Mn is likely linked to Mg deficiency in the leaf mesophyll. There was strong evidence that Mn toxicity in sugar maple is primarily a symplastic process. For each species, leaf-surface damage due to biotic stress including insect herbivory was compared between sites with acidified and non-acidified soils. Although it was greatest overall in red maple, there was no difference in biotic stress damage to red maple leaves between acidified and non-acidified soils. Sugar maple trees on buffered non-acidified soil were less damaged by biotic stress compared to those on unbuffered acidified soil, where they are also affected by Mn toxicity abiotic stress. This study concluded that foliar nutrient distribution in symplastic compartments is a determinant of Mn sensitivity, and that Mn stress hinders plant resistance to biotic stress.

  17. Distribution Pattern of Sweet Potato Whitefly Bemisia tabaci (Gennadius on Tomato Plants

    Directory of Open Access Journals (Sweden)

    K.M. Azam

    1997-01-01

    Full Text Available A field experiment was conducted to study the intra plant distribution and temporal dispersion patterns of whitetly (Bemisia tabaci Gennadius eggs and nymphs on tomato plants to establish a sampling method which would give accurate estimates of the population size. From the third week to the ninth week after transplanting, terminal leaflets were collected from the outer and inner canopies of each of the upper, middle, and lower plant strata. A strong ovipositional preference was found in whitefly adults at an early crop age. A maximum of 50.6% of the eggs were deposited in the middle stratum followed by upper (36. 15% and lower strata (13.3%. However, most of the nymphs (65.5% were present in the lower stratum followed by middle (32.4% and upper strata (2. l %. These findings indicated that when taking observations in egg counts the most preferred site is the upper and middle strata while for nymphal counts it is the lower and middle strata. There was a sharp decrease in egg and nymphal counts from the seventh week after transplantation which clearly indicated that, after this age , the corp is not preferred by whitefly . Egg and nymphal population of whitefly on tomato plants in the field were distributed in aggregates as evident by high variance to mean ratio. Values ranged from 2.72 to 14.36 and 4.52 to 21.82 for egg counts and nymphal population, respectively.  Aggregation of whitefly eggs and nymphs in all cases might be due to the behavior of adults to congregate and to the heterogeneity of the environment . The appropriate number of leaflets required for the estimation of egg density at 10% and 20% error was found to be 149 and 37, respectively. In the case of nymphal population the numbers were 163 and 41 at 10% and 20% error, respectively.

  18. [Interpretation of spatial distribution pattern for dissolved inorganic nitrogen concentration in coastal estuary using hyperspectral data].

    Science.gov (United States)

    Zhang, Dong; Xu, Yong; Zhang, Ying; Li, Huan

    2010-06-01

    Choosing dissolved inorganic nitrogen (DIN) as one of the representative nutritional salt monitoring indexes, a hyperspectral remotely sensed inversion model was built and applied to quantitatively retrieve water quality parameters with its spatial distribution patterns in coastal estuary with high suspended sediment concentration (SSC). It was found that when SSC was larger than 0.1 kg/m3, DIN concentration had a notable inverse correlation with SSC and the correlation coefficient R2 reached 0.617. Based on this conclusion, firstly the in-situ observed water surface remote sensing reflectance was resampled according to the spectral response characters of Hyperion sensor. And then, statistical correlation analysis between reflectance and DIN concentration was carried out. The results showed that band reflectance of R804 and R630 representing the second and first reflectance peak of water spectrum curve were sensitive to the variation of DIN concentration. And then, a pseudo remotely sensed sand parameter index R804 x R630/(R804 - R630) was calculated for the construction of the nonlinear DIN quantitative reversion model. Correlation coefficient R2 between observed and simulated DIN concentrations for 29 calibrating samples and 10 validating samples were 0.746 and 0.67, while their mean absolute errors reached 109.07 and 147.58 microg/L, respectively. The model was then applied on Hyperion hyperspectral image to get the spatial distribution character of DIN concentration in Sheyanghe river estuary and the DIN concentration was between 52 to 513 microg/L. Results indicated that in coastal estuary which was dominated by suspended sediments, the diffusive trends of DIN concentration reversed by remote sensing techniques had an intimate relationship with motions of tidal current and transportation attributes of SSC. As the hydrodynamic conditions were unclear, hyperspectral remote sensing technique was an effective technical way for dynamic survey of DIN concentration.

  19. Tissue-specific expression pattern and histological distribution of NLRP3 in Chinese yellow chicken.

    Science.gov (United States)

    Ye, Jinhui; Yu, Meng; Zhang, Kaizhao; Liu, Jianxin; Wang, Qingnan; Tao, Pan; Jia, Kun; Liao, Ming; Ning, Zhangyong

    2015-09-01

    Pathogen-associated molecular patterns (PAMPs) play important role in inflammation which means response of the host to stimuli. NOD-like receptor protein 3 (NLRP3) inflammasome is involved in the onset and development of inflammation. NLRP3, as one of the most important inflammasome sensors, has significant effect on the regulation of inflammasome activation to avoid the consequences of over activation. Up to date, there are no detailed tissue specific expression and distribution data about NLPR3 in chicken. Here, NLRP3 of Chinese yellow chicken was cloned and sequence analyzed, the polyclonal antibody was produced by purified protein of recombinant prokaryotic expression. Relative expression levels and tissue distribution of NLRP3 were investigated by real-time quantitative PCR and immunohistochemical analysis, respectively. The results showed that NLRP3 gene is highly variable between mammalian and avian. The nucleotide homology of NLRP3 between yellow chicken and Bos taurus, Hainan black goat, Sus scrofa, Callithrix jacchus, Homo sapiens, Macaca mulatta, Mus musculus and Rattus norvegicus were 54.2%, 53.9%, 53.7%, 55.4%, 54.3%, 54.5%, 53.5% and 53.7%. NLRP3 expressed in all detected tissues and higher in the trachea are lung than in other tissues. Cytoplasmic expression of NLRP3 was detected in ciliated epithelial cells, basal cells and cells in lamina propria of trachea, alveolar epithelial cells, cardiac muscle cells, cerebral cortex neurons, epithelial reticular cells of the spleen, and lymphocytes of medulla in stannius follicle, liver cells and the renal tubule epithelial cells. The results will help to elucidate the role of NLRP3 of different tissues in inflammatory diseases of chicken and provide a basis for further investigations in the function and evolution of NLRP3 in different species, which would be helpful for further research on avian inflammatory diseases.

  20. Unraveling Salt Tolerance Mechanisms in Halophytes: A Comparative Study on Four Mediterranean Limonium Species with Different Geographic Distribution Patterns

    Directory of Open Access Journals (Sweden)

    Mohamad Al Hassan

    2017-08-01

    Full Text Available We have performed an extensive study on the responses to salt stress in four related Limonium halophytes with different geographic distribution patterns, during seed germination and early vegetative growth. The aims of the work were twofold: to establish the basis for the different chorology of these species, and to identify relevant mechanisms of salt tolerance dependent on the control of ion transport and osmolyte accumulation. Seeds were germinated in vitro, in the presence of increasing NaCl concentrations, and subjected to “recovery of germination” tests; germination percentages and velocity were determined to establish the relative tolerance and competitiveness of the four Limonium taxa. Salt treatments were also applied to young plants, by 1-month irrigation with NaCl up to 800 mM; then, growth parameters, levels of monovalent and divalent ions (in roots and leaves, and leaf contents of photosynthetic pigments and common osmolytes were determined in control and stressed plants of the four species. Seed germination is the most salt-sensitive developmental phase in Limonium. The different germination behavior of the investigated species appears to be responsible for their geographical range size: L. narbonense and L. virgatum, widespread throughout the Mediterranean, are the most tolerant and the most competitive at higher soil salinities; the endemic L. santapolense and L. girardianum are the most sensitive and more competitive only at lower salinities. During early vegetative growth, all taxa showed a strong tolerance to salt stress, although slightly higher in L. virgatum and L. santapolense. Salt tolerance is based on the efficient transport of Na+ and Cl− to the leaves and on the accumulation of fructose and proline for osmotic adjustment. Despite some species-specific quantitative differences, the accumulation patterns of the different ions were similar in all species, not explaining differences in tolerance, except for the

  1. [Population structure and spatial distribution pattern of Camellia azalea in E' huangzhang Nature Reserve of Guangdong, China].

    Science.gov (United States)

    Li, Xin-lei; Sun, Zhen-yuan; Li, Ji-yuan; Xu, Yi; Luo, Jian

    2013-08-01

    This paper studied the structures of basal diameter, height and canopy width of Camellia azalea population in E' huangzhang Nature Reserve of Guangdong. The spatial distribution patterns and dynamics of the population were measured by applying aggregate indices including disperse coefficient, negative binomial distribution, Cassie index, clumping index, mean crowding, patch index and Green index. The results showed that in the natural distribution region, the population was mainly composed of adult trees, and was in declining due to seriously lack of seedlings. The structures of diameter, height and canopy width were not identical among different plots. In the plots, the spatial distribution pattern of C. azalea population showed clump or random, and changed from clump to random with the development of the population.

  2. Diversity and distribution patterns of the Oligocene and Miocene decapod crustaceans (Crustacea: Malacostraca of the Western and Central Paratethys

    Directory of Open Access Journals (Sweden)

    Hyžný Matúš

    2016-10-01

    Full Text Available Decapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19th century, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic “Schlier”-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution

  3. Diversity and distribution patterns of the Oligocene and Miocene decapod crustaceans (Crustacea: Malacostraca) of the Western and Central Paratethys

    Science.gov (United States)

    Hyžný, Matúš

    2016-10-01

    Decapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19th century, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global) extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic "Schlier"-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution during the Oligo

  4. Thermal Contraction Crack Polygon Classification and Distribution: Morphological Variations in Northern Hemisphere Patterned Ground

    Science.gov (United States)

    Levy, J.; Head, J.; Marchant, D.

    2008-09-01

    provides context for interpretation of contraction crack polygons at the NASA Phoenix landing site. Survey Parameters We present an updated survey of 413 HiRISE images of the martian northern hemisphere (30-80°N), at resolutions of ~30 cm/pixel, spanning primary science phase orbits 001331 to 007492 [18]. Of the surveyed images, 276 contain polygonally patterned ground (69%). Polygon diameters were measured using centre-to-centre point distance measurements between adjacent polygons, and were averaged across the four nearest-neighbour points to give a representative diameter. Polygon Classification and Distribution We divide polygons into 8 morphological types (Figure 1). Commonly more than one type is present in a single HiRISE image, suggesting variability in polygon-forming substrate conditions on 100 m to km length scales [19]. Polygon types are strongly grouped by latitude, transitioning from one to the next across the studied latitude range. High Relief (HR). Initially described by [16], HR polygons are well-formed and have strong contrasts between polygon centres and depressed polygon margin troughs. HR are morphologically similar to S1 terrain described by [3], averaging ~6 m in diameter (N = 160). HR polygon distribution is centred at 69.4°N. Northern Plains (NP1-3). Northern plains polygons are the predominant northern hemisphere polygon species (196 occurrences). NP are present in the vicinity of the Phoenix lander [16], and occur in three varieties: NP1, consisting of well-formed, low-troughed polygons present on boulder-topped mounds (mean diameter ~5 m, N = 138); NP2, consisting of less-sharply defined polygons, present on both smooth, and gently hummocked surfaces (mean diameter ~5 m, N = 121); and NP3, which are poorly polygonalized features, commonly consisting of long, sinuous cracks which form coarse networks (mean diameter ~6 m, N = 147). Polygons at the Phoenix lander site appear to be NP2/NP3. NP polygons are all broadly similar to the S group

  5. Species distribution and antifungal susceptibility pattern of Candida causing oral candidiasis among hospitalized patients

    Directory of Open Access Journals (Sweden)

    Faseela Taivalap Shafi

    2015-01-01

    Full Text Available Background: Oral candidiasis is increasingly seen among hospitalized patients and is usually treated empirically. It can be the marker of systemic infection. Antifingal resistance is one of the emerging problems in candidiasis. Aim and Objectives: To study the distribution pattern of various Candida species among hospitalised patients with oral candidiasis, to detect the antifungal resistance among Candida and to assess the possible risk factors associated with those patients. Methods: Out of 300 patients screened, oral thrush material was collected from 36 patients having oral candidiasis. Candida spp. were isolated and identified. Antifungal susceptibility test was performed by disk diffusion method. Results: Candida albicans was the most frequently isolated species (64%. Highest resistance was seen with ketoconazole (18%. Except one C. tropicalis, all the isolates were sensitive to amphotericin B. All the patients were on broad spectrum antibiotic treatment. Diabetes mellitus was seen in 50 % of the patients. Other predisposing factors include tuberculosis, COPD, cancer and steroid treatment. Conclusion: Eventhough there is progressive shift from a predominance of C. albicans to non-albicans Candida species in candidiasis, C. albicans remains as the most important pathogen in oral candidiasis. Since azole resistance is increasing, accurate identification of Candida spp. and antifungal susceptibility testing is crucial for patient management and for facilitating hospital control measures.

  6. Patterns of Glycoconjugate Distribution during Molar Tooth Germ Development in Mice

    Directory of Open Access Journals (Sweden)

    AR. Varasteh

    2007-09-01

    Full Text Available Objective: The aim of the present study was to evaluate the structure and distribution of Glycoconjugates during molar tooth germ development in mice.Materials and Methods: Sixteen tooth germs were obtained from BALB/c mice embryos 15 to 18 days post-gestation and fixed in 10% formalin. After routine tissue processing, 5μm sections were cut and stained with BSA1-B4 and PNA using the lectin histochemical method. All slides were evaluated by light microscopy.Results: Both lectins showed positive reaction in the tooth germ but with spatiotemporal differences. During bell stage, the reaction was strong with BSA1-B4 but moderate with PNA. Strong PNA uptake was observed in the odontoblastic and ameloblastic nuclei alongwith the apical cytoplasm of the ameloblasts.Conclusion: Although the lectins that were used in the present study recognize the same terminal sugar residue, they reacted with different disaccharide sequences with various penaltomer sugars. Therefore it may be assumed that the pattern of affinity for different parts of the developing tooth germ such as ameloblasts and odontoblasts is different in various lectins.

  7. Distribution patterns suggest biomagnification of halogenated 1'-methyl-1,2'-bipyrroles (MBPs).

    Science.gov (United States)

    Pangallo, Kristin C; Reddy, Christopher M

    2009-01-01

    The halogenated 1'-methyl-1,2'-bipyrroles (MBPs) are a suite of marine natural products that have been detected in marine mammals worldwide. Although their concentrations are similar to persistent organic pollutants that biomagnify, such as 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), it is notyet clearthat these natural products also biomagnify. Here we analyze MBPs and CB-153 isolated from the blubber and liver of marine mammals stranded on the eastern coast of Massachusetts. Four odontocete species (Delphinus delphis, Lagenorhynchus acutus, Phocoena phocoena, and Globicephala melas) and two pinniped species (Halichoerus grypus and Phoca groenlandica) were sampled. MBPs were present in all odontocetes, but not detected in pinnipeds; CB-153 was detected in every species. MBP patterns indicative of biomagnification were found, including age-dependent concentration increases and reduced concentrations in adult females. Also explored were the similarities and differences with CB-153, the effects of nutritional state on contaminant distribution, and the maternal transfer of blubber-based organic contaminants.

  8. Evidences Dependent Population Distribution Patterns of Tiger and Leopard in Similipal Tiger Reserve, Odisha, India

    Directory of Open Access Journals (Sweden)

    Sandeep Ranjan Mishra

    2015-10-01

    Full Text Available The Tiger (Panthera tigris is an endangered carnivore with uncertain demographic status spanning 13 Asian countries. Due to its larger body size and carnivorous diet in nature it always occurs at low population densities. Further prey depletion due to overhunting (Karanth & Stith, 1998, poaching, habitat shrinkage (Kenny et al., 1995, Wcs, 1995 and direct killing altogether have also become a major factor for depletion of wild tiger populations tiger. Monitoring the abundance and its alteration is always important for the effective management of endangered species. Tiger is categorized as “Endangered” on the IUCN Red List (IUCN, 2008 and listed under Schedule-I of Wildlife (Protection Act, 1972 in India and Appendix-I of the CITES. Leopard (Panthera pardus is also included in the Schedule- I of the Indian Wildlife Protection Act, 1972 and is placed under “Least Concern” category of 2002 IUCN Red List of threatened animals. Similipal Tiger Reserve is one of the largest Tiger Reserves of India with an area of 2750 km2. Therefore we have to depend mainly on the direct sightings and evidence records of the animals to analysis the status and distribution pattern of these two big cats in the core area of this Tiger Reserve.

  9. Limnocythere (Ostracoda) distribution pattern in the Southern Ethiopian Rift during the Late Pleistocene and Holocene

    Science.gov (United States)

    Viehberg, Finn; Gebru, Tsige; Foerster, Verena; Schaebitz, Frank; Wagner, Bernd

    2014-05-01

    Sediment records from two lakes in the biodiversity hotspot of the Southern Ethiopian Rift were retrieved, Lake Chamo (c. 9 ka) and Chew Bahir (c. 45 ka). Sedimentological and palaeoecological proxies infer rapidly changing environmental conditions (wet-dry cycle) such as the African Humid Period. The fossil record in both archives is fairly rich in ostracode taxa throughout the cores and especially diverse in the genus Limnocythere. Here, we discuss the temporal and spatial distribution pattern of Limnocythere species in the Omo-Turkana basin in the context of palaeolimnological changes. In addition, we mapped extensively valve characteristics of the L. species to document morphological intraspecific variation also as a supplementary measure of environmental change. Our preliminary results show that regional biogeographical boundaries might have changed as a consequence, too. For instance, members of the Limnocythere thomasi -group (sensu Martens 1990) occur in our fossil record. In modern studies this species cluster is regarded as endemic fauna of Lakes Zway, Langano and Shala, which are associated with the freshwater ecoregion of the Northern Eastern Rift.

  10. A tale of two genomes: contrasting patterns of phylogeographic structure in a widely distributed bat.

    Science.gov (United States)

    Turmelle, Amy S; Kunz, Thomas H; Sorenson, Michael D

    2011-01-01

    One of the most widely distributed bats in the New World, the big brown bat (Eptesicus fuscus) exhibits well-documented geographic variation in morphology and life history traits, suggesting the potential for significant phylogeographic structure as well as adaptive differentiation among populations. In a pattern broadly consistent with morphologically defined subspecies, we found deeply divergent mitochondrial lineages restricted to different geographic regions. In contrast, sequence data from two nuclear loci suggest a general lack of regional genetic structure except for peripheral populations in the Caribbean and Mexico/South America. Coalescent analyses suggest that the striking difference in population structure between genomes cannot be attributed solely to different rates of lineage sorting, but is likely due to male-mediated gene flow homogenizing nuclear genetic diversity across most of the continental range. Despite this ongoing gene flow, selection has apparently been effective in producing and maintaining adaptive differentiation among populations, while strong female site fidelity, maintained over the course of millions of years, has produced remarkably deep divergence among geographically isolated matrilines. Our results highlight the importance of evaluating multiple genetic markers for a more complete understanding of population structure and history. © 2010 Blackwell Publishing Ltd.

  11. Habitat Preferences, Distribution Pattern, and Root Weight Estimation of Pasak Bumi (Eurycoma longifolia Jack.

    Directory of Open Access Journals (Sweden)

    Siti Masitoh Kartikawati

    2014-04-01

    Full Text Available Pasak bumi (Eurycoma longifolia Jack is one of non timber forest products with “indeterminate” conservation status and commercially traded in West Kalimantan. The research objective was to determine the potential of pasak bumi root per hectare and its ecological condition under natural habitat. Root weight of E. longifolia Jack was estimated using simple linear regression and exponential equation with stem diameter and height as independent variables. The results showed that the individual number of the population was 114 with the majority in seedling stage with 71 individuals (62.28%. The distribution was found in clumped pattern. Conditions of the habitat could be described as follows: daily average temperature of 25.6oC, daily average relative humidity of 73.6%, light intensity of 0.9 klx, and red-yellow podsolic soil with texture ranged from clay to sandy clay. The selected estimator model for E. longifolia Jack root weight used exponential equation with stem height as independent variable using the equation of Y= 21.99T0,010 and determination coefficient of 0.97. After height variable was added, the potential of E. longifolia Jack minimum root weight that could be harvested per hectare was 0.33 kg.

  12. Spatial Distribution and Temporal Patterns of Cassin?s Auklet Foraging and Their Euphausiid Prey in a Variable Ocean Environment

    OpenAIRE

    Suzanne Manugian; Elliott, Meredith L.; Russ Bradley; Julie Howar; Nina Karnovsky; Benjamin Saenz; Anna Studwell; Pete Warzybok; Nadav Nur; Jaime Jahncke

    2015-01-01

    Krill (Euphausiids) play a vital ecosystem role in many of the world's most productive marine regions, providing an important trophic linkage. We introduce a robust modeling approach to link Cassin's auklet (Ptychoramphus aleuticus) abundance and distribution to large-scale and local oceanic and atmospheric conditions and relate these patterns to similarly modeled distributions of an important prey resource, krill. We carried out at-sea strip transect bird surveys and hydroacoustic assessment...

  13. Pan-Arctic aerosol number size distributions: seasonality and transport patterns

    Directory of Open Access Journals (Sweden)

    E. Freud

    2017-07-01

    Full Text Available The Arctic environment has an amplified response to global climatic change. It is sensitive to human activities that mostly take place elsewhere. For this study, a multi-year set of observed aerosol number size distributions in the diameter range of 10 to 500 nm from five sites around the Arctic Ocean (Alert, Villum Research Station – Station Nord, Zeppelin, Tiksi and Barrow was assembled and analysed.A cluster analysis of the aerosol number size distributions revealed four distinct distributions. Together with Lagrangian air parcel back-trajectories, they were used to link the observed aerosol number size distributions with a variety of transport regimes. This analysis yields insight into aerosol dynamics, transport and removal processes, on both an intra- and an inter-monthly scale. For instance, the relative occurrence of aerosol number size distributions that indicate new particle formation (NPF event is near zero during the dark months, increases gradually to  ∼ 40 % from spring to summer, and then collapses in autumn. Also, the likelihood of Arctic haze aerosols is minimal in summer and peaks in April at all sites.The residence time of accumulation-mode particles in the Arctic troposphere is typically long enough to allow tracking them back to their source regions. Air flow that passes at low altitude over central Siberia and western Russia is associated with relatively high concentrations of accumulation-mode particles (Nacc at all five sites – often above 150 cm−3. There are also indications of air descending into the Arctic boundary layer after transport from lower latitudes.The analysis of the back-trajectories together with the meteorological fields along them indicates that the main driver of the Arctic annual cycle of Nacc, on the larger scale, is when atmospheric transport covers the source regions for these particles in the 10-day period preceding the observations in the Arctic. The scavenging of these particles

  14. Phylogeographic pattern of Rhizophora (Rhizophoraceae) reveals the importance of both vicariance and long-distance oceanic dispersal to modern mangrove distribution.

    Science.gov (United States)

    Lo, Eugenia Y Y; Duke, Norman C; Sun, Mei

    2014-04-17

    Mangroves are key components of coastal ecosystems in tropical and subtropical regions worldwide. However, the patterns and mechanisms of modern distribution of mangroves are still not well understood. Historical vicariance and dispersal are two hypothetic biogeographic processes in shaping the patterns of present-day species distributions. Here we investigate evolutionary biogeography of mangroves in the Indo-West Pacific (IWP) and western Atlantic-East Pacific (AEP) regions using a large sample of populations of Rhizophora (the most representative mangrove genus) and a combination of chloroplast and nuclear DNA sequences and genome-wide ISSR markers. Our comparative analyses of biogeographic patterns amongst Rhizophora taxa worldwide support the hypothesis that ancient dispersals along the Tethys Seaway and subsequent vicariant events that divided the IWP and AEP lineages resulted in the major disjunctions. We dated the deep split between the Old and New World lineages to early Eocene based on fossil calibration and geological and tectonic changes. Our data also provide evidence for other vicariant processes within the Indo-West Pacific region in separating conspecific lineages of SE Asia and Australia-Pacific at the Oligocene-Miocene boundary. Close genetic affinities exist between extant Fijian and American lineages; East African and Australian lineages; and Australian and Pacific lineages; indicating relatively more recent oceanic long-distance dispersal events. Our study demonstrates that neither vicariance nor dispersal alone could explain the observed global occurrences of Rhizophora, but a combination of vicariant events and oceanic long-distance dispersals can account for historical diversification and present-day biogeographic patterns of mangroves.

  15. Acacia trees pattern distribution as an indicator for changes in flow spatial distributions in a hyper-arid environment

    Science.gov (United States)

    Isaacson, Sivan; Ephrath, Jhonathan E.; Rachmilevitch, Shimon; Maman, Shimrit; Blumberg, Dan G.

    2017-04-01

    Arid regions are characterized by high spatial and temporal variability of precipitation, resulting in high spatial and temporal variation of vegetation cover. Because of low rainfall, the acacia trees in southern Israel are usually restricted to ephemeral stream (Wadi) beds, which possess higher soil moisture content than the surrounding landscape. Spatial analyses of tree distribution at the drainage basin scale contributes to a better understanding of the geo-hydrologic regime because water is the main limiting factor in such areas. That is, the spatial distribution of trees and their characteristics within the Wadi may reflect the spatial variance of water availability within different segments of the Wadi. The main objective of this study was to use the spatial distribution of different parameters of acacia trees as an indicator of past and present hydrological regimes within different segments of the Wadi. Tree size distribution was used as an indicator of long-term (decades) geo-hydrologic spatial processes affecting the acacia population. The tree health (NDVI) distribution was used as an indicator of short-term (months to a few years) geo-hydrologic spatial processes, such as the paths of recent flashfloods events. The distribution of the trees in the Wadi (ephemeral river) was divided into three distinct categories: (1) large trees with high NDVI values, (2) large trees with low NDVI values and (3) small trees with medium NDVI values. Using the resulting classification, we divided the Wadi into three sections, each representing a unique combination of long- and short-term geo-hydrologic processes affecting the acacia trees. We suggest that the lack of spatial correlation between tree size and health status is a result of spatio-temporal changes in the water supply. Our main conclusion is that past and current alterations of the runoff path can be detected by the spatial analysis of trees in hyper-arid regions

  16. Sleep-wake distribution and circadian patterns of epileptic seizures in children.

    Science.gov (United States)

    Gurkas, Esra; Serdaroglu, Ayse; Hirfanoglu, Tugba; Kartal, Ayse; Yılmaz, Unsal; Bilir, Erhan

    2016-07-01

    Epilepsy is one of the most common chronic neurologic disorders. Daily periodicity of epileptic seizures has been known for over a century. The diurnal patterns of epileptic seizures have also been observed in studies. To investigate the sleep/wake cycle, day/night, and 24-h periodicity of various seizure subtypes and seizure onset localizations in children. We analyzed the clinical seizures of 170 consecutive epilepsy patients who underwent video-electroencephalography (EEG) monitoring over the last 5 years. Semiology of the seizures was classified according to the semiological seizure classification. Origin of the seizures was defined by the onset of ictal activity on EEG. Seizures were evaluated in terms of occurrence during the day (06:00-18:00 h) or night (18:00-06:00 h), in wakefulness or in sleep, and within a 3-h time interval throughout 24 h. A total of 909 seizures were analyzed. Auras, dialeptic, myoclonic, hypomotor, atonic seizures, and epileptic spasms occurred more frequently in wakefulness; tonic, clonic, and hypermotor seizures occurred more frequently in sleep. Auras, dialeptic, and atonic seizures and epileptic spasms occurred more often during daytime; hypermotor seizures occurred more often at night. Generalized seizures were seen most frequently in wakefulness (between 12:00 and 18:00 h); frontal lobe seizures were seen at night and in sleep (between 24:00 and 03:00 h); temporal lobe seizures were seen in wakefulness (between 06:00 and 09:00 h and between 12:00 and 15:00 h); occipital seizures were seen during daytime and in wakefulness (between 09:00 and 12:00 h and between 15:00 and 18:00 h, respectively); parietal seizures were seen mostly during daytime. Seizures in children occur in specific circadian patterns and in specific sleep/wake distributions depending on seizure onset location and semiology. Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  17. Patterns of biomass and carbon distribution across a chronosequence of Chinese pine (Pinus tabulaeformis forests.

    Directory of Open Access Journals (Sweden)

    Jinlong Zhao

    Full Text Available Patterns of biomass and carbon (C storage distribution across Chinese pine (Pinus tabulaeformis natural secondary forests are poorly documented. The objectives of this study were to examine the biomass and C pools of the major ecosystem components in a replicated age sequence of P. tabulaeformis secondary forest stands in Northern China. Within each stand, biomass of above- and belowground tree, understory (shrub and herb, and forest floor were determined from plot-level investigation and destructive sampling. Allometric equations using the diameter at breast height (DBH were developed to quantify plant biomass. C stocks in the tree and understory biomass, forest floor, and mineral soil (0-100 cm were estimated by analyzing the C concentration of each component. The results showed that the tree biomass of P. tabulaeformis stands was ranged from 123.8 Mg·ha-1 for the young stand to 344.8 Mg·ha-1 for the mature stand. The understory biomass ranged from 1.8 Mg·ha-1 in the middle-aged stand to 3.5 Mg·ha-1 in the young stand. Forest floor biomass increased steady with stand age, ranging from 14.9 to 23.0 Mg·ha-1. The highest mean C concentration across the chronosequence was found in tree branch while the lowest mean C concentration was found in forest floor. The observed C stock of the aboveground tree, shrub, forest floor, and mineral soil increased with increasing stand age, whereas the herb C stock showed a decreasing trend with a sigmoid pattern. The C stock of forest ecosystem in young, middle-aged, immature, and mature stands were 178.1, 236.3, 297.7, and 359.8 Mg C ha-1, respectively, greater than those under similar aged P. tabulaeformis forests in China. These results are likely to be integrated into further forest management plans and generalized in other contexts to evaluate C stocks at the regional scale.

  18. Patterns of Biomass and Carbon Distribution across a Chronosequence of Chinese Pine (Pinus tabulaeformis) Forests

    Science.gov (United States)

    Wang, Luoxin; Yu, Xiaowen; Zhao, Weihong; Song, Xiaoshuai; Zhang, Yanlei; Chen, Feng; Sun, Yu; He, Tengfei; Han, Hairong

    2014-01-01

    Patterns of biomass and carbon (C) storage distribution across Chinese pine (Pinus tabulaeformis) natural secondary forests are poorly documented. The objectives of this study were to examine the biomass and C pools of the major ecosystem components in a replicated age sequence of P. tabulaeformis secondary forest stands in Northern China. Within each stand, biomass of above- and belowground tree, understory (shrub and herb), and forest floor were determined from plot-level investigation and destructive sampling. Allometric equations using the diameter at breast height (DBH) were developed to quantify plant biomass. C stocks in the tree and understory biomass, forest floor, and mineral soil (0–100 cm) were estimated by analyzing the C concentration of each component. The results showed that the tree biomass of P. tabulaeformis stands was ranged from 123.8 Mg·ha–1 for the young stand to 344.8 Mg·ha–1 for the mature stand. The understory biomass ranged from 1.8 Mg·ha–1 in the middle-aged stand to 3.5 Mg·ha–1 in the young stand. Forest floor biomass increased steady with stand age, ranging from 14.9 to 23.0 Mg·ha–1. The highest mean C concentration across the chronosequence was found in tree branch while the lowest mean C concentration was found in forest floor. The observed C stock of the aboveground tree, shrub, forest floor, and mineral soil increased with increasing stand age, whereas the herb C stock showed a decreasing trend with a sigmoid pattern. The C stock of forest ecosystem in young, middle-aged, immature, and mature stands were 178.1, 236.3, 297.7, and 359.8 Mg C ha–1, respectively, greater than those under similar aged P. tabulaeformis forests in China. These results are likely to be integrated into further forest management plans and generalized in other contexts to evaluate C stocks at the regional scale. PMID:24736660

  19. Explaining the evaporation paradox in Jiangxi Province of China: Spatial distribution and temporal trends in potential evapotranspiration of Jiangxi Province from 1961 to 2013

    Directory of Open Access Journals (Sweden)

    Xianghui Lu

    2016-03-01

    Full Text Available Evaporation acts as an important component and a key control factor in land hydrological processes. In order to analyze the trend of change on potential evapotranspiration from 1961 to 2013 and to discuss the existence of the evaporation paradox in Jiangxi province, China, monthly meteorological data spanning the years 1961–2013 were analyzed in this study, where the data were collected from 15 national meteorological stations in Jiangxi Province. The Penman–Monteith equation was employed to compute the potential evapotranspiration (ET0. Spatial interpolation and data mining technology were used to analyze the spatial and temporal changes of ET0 and air temperature, with the effort to explain the evaporation paradox. By solving the total differential and the partial derivatives coefficients of the independent variables in Penman–Monteith equation, the cause of the paradox was quantitatively evaluated. The results showed that the annual ET0 had been decreasing significantly in Jiangxi Province since 1979, whereas the air temperature had been rising significantly, presenting the evaporation paradox. The decreases in sunshine duration and wind speed reduced ET0 by 0.207 mm and 0.060 mm, respectively, accounting for 92.3% and 26.7% of the total ET0, respectively. It is concluded that sunshine duration and wind speed are the main causes to the decrease in potential evapotranspiration in Jiangxi Province.

  20. Wave-like distribution patterns of Gfp-marked Pseudomonas fluorescens along roots of wheat plants grown in two soils

    NARCIS (Netherlands)

    Bruggen, van A.H.C.; Semenov, A.M.; Zelenev, V.V.; Semenov, A.V.; Raaijmakers, J.M.; Sayler, R.J.; Vos, de O.J.

    2008-01-01

    Culturable rhizosphere bacterial communities had been shown to exhibit wave-like distribution patterns along wheat roots. In the current work we show, for the first time, significant wave-like oscillations of an individual bacterial strain, the biocontrol agent Pseudomonas fluorescens 32 marked with

  1. Spatial and depth-associated distribution patterns of shallow gorgonians in the Algarve coast (Portugal, NE Atlantic)

    Science.gov (United States)

    Cúrdia, João; Monteiro, Pedro; Afonso, Carlos M. L.; Santos, Miguel N.; Cunha, Marina R.; Gonçalves, Jorge M. S.

    2013-09-01

    The ecological role of gorgonians for marine rocky bottoms is worldwide recognized, but the information on the distribution patterns of NE Atlantic temperate species is insufficient, considering current global, regional and local threats. To overcome the lack of information on the spatial distribution patterns of gorgonians in south Portugal, in 2009/2010, the occurrence and abundance of gorgonian species in rocky bottoms were quantified over more than 25 km of coast (37.1°N/8.6°W) down to 30 m depth. Eunicella labiata, Eunicella gazella, Eunicella verrucosa and Leptogorgia sarmentosa were abundant and frequent in the studied area, while Leptogorgia lusitanica was less abundant. All species evidenced a similar depth pattern, that is abundance significantly increased with depth below 15 m. At shallower waters (up to 15 m), the distribution of gorgonians may be constrained by abiotic factors and competition with algae. Indeed, the abundance of gorgonians was negatively correlated with the percentage cover of algae along the depth gradient, but gorgonians and sponges coexist. Competition among gorgonian species also seems to be low in this area because of the similarity in the abundance pattern observed for the most abundant species and also their high association. In NE Atlantic shallow temperate rocky bottoms, the distribution of gorgonians seems to be influenced by environmental factors and biological interactions, namely competition (algae) and coexistence (sponges and other gorgonians).

  2. Bipolar Plasma Membrane Distribution of Phosphoinositides and Their Requirement for Auxin-Mediated Cell Polarity and Patterning in Arabidopsis

    NARCIS (Netherlands)

    Tejos, R.; Sauer, M.; Vanneste, S.; Palacios-Gomez, M.; Li, H.; Heilmann, M.; van Wijk, R.; Vermeer, J.E.M.; Heilmann, I.; Munnik, T.; Friml, J.

    2014-01-01

    Cell polarity manifested by asymmetric distribution of cargoes, such as receptors and transporters, within the plasma membrane (PM) is crucial for essential functions in multicellular organisms. In plants, cell polarity (re)establishment is intimately linked to patterning processes. Despite the

  3. Fetal and infant growth patterns associated with total and abdominal fat distribution in school-age children

    NARCIS (Netherlands)

    Gishti, O.; Gaillard, R.; Manniesing, R.; Abrahamse-Berkeveld, M.; Beek, E.M. van der; Heppe, D.H.M.; Steegers, E.A.P.; Hofman, A.; Duijts, L.; Durmus, B.u.; Jaddoe, V.W.

    2014-01-01

    Context: Higher infant growth rates are associated with an increased risk of obesity in later life. Objective: We examined the associations of longitudinally measured fetal and infant growth patterns with total and abdominal fat distribution in childhood. Design, Settings and participants:We

  4. Earthworm abundance and distribution pattern in contrasting plant communities within a tropical wet forest in Puerto Rico

    Science.gov (United States)

    G. Gonzalez; X. Zou; A. Sabat; N. Fetcher

    1999-01-01

    Plant communities may impose strong control on soil fauna properties. We examined the abundance and distribution pattern of earthworms in two contrasting plant communities within a tropical wet forest in Puerto Rico. The Dacryodes community occurs in well-drained soils and is dominated by Dacryodes excels, Manilkara bidentata, Guarea guidonea, and Sloanea berteriana....

  5. Late Quaternary palynology in marine sediments: a synthesis of the understanding of pollen distribution patterns in the NW African setting.

    NARCIS (Netherlands)

    Hooghiemstra, H.; Lézine, A.M.; Leroy, S.A.G.; Dupont, L.; Marret, F.

    2006-01-01

    Abstract After a review of the first steps in marine palynology, we show that the understanding of the northwest African setting is crucial to evaluate the potential of marine palynological studies elsewhere. We studied distribution patterns of pollen grains in recent marine sediments off NW Africa

  6. Patterns of organic osmolytes in two marine bivalves, Macoma balthica, and Mytilus spp., along their European distribution

    NARCIS (Netherlands)

    Kube, S.; Gerber, A.; Jansen, J.M.; Schiedek, D.

    2006-01-01

    Patterns of nine intracellular free amino acids (FAA), which are utilized as organic osmolytes for salinity-induced cell volume regulation in marine osmoconformers, were compared in five Macoma balthica populations and seven Mytilus spp. populations along their European distribution. Three types of

  7. Distribution of airborne microbes and antibiotic susceptibility pattern of bacteria during Gwalior trade fair, Central India.

    Science.gov (United States)

    Yadav, Jayprakash; Kumar, Awanish; Mahor, Pawan; Goel, Ajay Kumar; Chaudhary, Hotam Singh; Yadava, Pramod Kumar; Yadav, Hariom; Kumar, Pramod

    2015-07-01

    Research into the distribution of bioaerosols during events associated with huge groups of people is lacking, especially in developing countries. The purpose of this study was to understand the distribution pattern of bioaerosols during an annual trade fair in the historical city of Gwalior, central India, a very important historical fair that was started by the King of Gwalior Maharaja Madho Rao in 1905. Air samples were collected from six different sites at the fair ground and three different sites in a residential area before/during/after the fair using an impactor sampler on microbial content test agar and rose bengal agar for total bacteria and fungi, respectively. The representative strains of bacteria and fungi were further identified and selected bacterial strains were subjected to antibiotic susceptibility testing according to US Clinical and Laboratory Standards Institute (CLSI) guidelines. The bacterial bioaerosol count [colony-forming units (CFU)/m(3)] at fair sites was found to be 9.0 × 10(3), 4.0 × 10(4), and 1.0 × 10(4) before the start of the fair, during the fair, and after the fair, respectively. The fungal bioaerosol count at fair sites was 2.6 × 10(3) CFU/m(3), 6.3 × 10(3) CFU/m(3), and 1.7 × 10(3) CFU/m(3) before the fair, during the fair, and after the fair, respectively. Bacterial/fungal bioaerosols during-fair were increased significantly from the bacterial/fungal bioaerosols of the before-fair period (p fair sites during the event (p fair ground was significantly increased during-fair and was still higher in the after-fair period. Methicillin-resistant staphylococci (MRS) were also reported at the fair ground. The study indicates significantly higher bacterial and fungal bioaerosols during the fair event. Therefore, further research is needed to explore the health aspects and guidelines to control microbial load during such types of events. Copyright © 2013. Published by Elsevier B.V.

  8. Patterns of Carbon Source and Sink Distribution in Canada's Forests Resulting From Disturbance and Climate Change

    Science.gov (United States)

    Chen, J. M.; Cihlar, J.; Amiro, B.; Ju, W.; Price, D.; Liu, J.; Pan, J.

    2001-12-01

    Major forest disturbance includes fires, inset-induced mortality, and timber harvest. The direct release of carbon from Canada's forests due to disturbance amounts to 150 Mt/y in some years, which is about 1.5 percent of the net primary productivity (NPP) of all Canada's forests (~420 Mha.). The mean carbon release due to disturbance in 1990-1998 was about 60 percent of net ecosystem productivity (NEP) of all undisturbed Canada's forests. The disturbance effects have been estimated in previous studies, either based on eco-region disturbance statistics in 5 year time steps, or Canada-mean values in annual time steps. However, large improvements in the estimation are still possible when spatially explicit information is used. For this purpose, 10-day cloud-free synthesis images of VEGETATION onboard SPOT-4, acquired in June-August, 1998, are used to derive a Canada-wide fire scar age distribution for up to 25 years. The spatial resolution of the fire scars is 1 km. This information is combined with gridded forest inventory of forest stand age at 10 km resolution to complete the age distribution at 1998. Forest regeneration is assumed to start 1 year after disturbance, but the regrowth is slower at locations with lower annual temperatures. An ecosystem model, named InTEC, is used to assimilate satellite-derived land cover and leaf area index maps, gridded climate (1901-1998) and soil data, and this forest stand age map, and to calculate NPP, NEP and net biome productivity (NBP) for each 1 km pixel at annual time steps. Both direct carbon release and forest regrowth after disturbance are modeled. The NBP maps of Canada in recent years show: (i) large spatial variations corresponding to patterns of recent fire scars and forest types, and (ii) a general south-to-north gradient of decreasing sink strength and increasing source strength. This gradient results mostly from different effects of temperature increase on growing season length, nutrient mineralizaton, and

  9. Within-twig leaf distribution patterns differ among plant life-forms in a subtropical Chinese forest.

    Science.gov (United States)

    Meng, Fengqun; Cao, Rui; Yang, Dongmei; Niklas, Karl J; Sun, Shucun

    2013-07-01

    In theory, plants can alter the distribution of leaves along the lengths of their twigs (i.e., within-twig leaf distribution patterns) to optimize light interception in the context of the architectures of their leaves, branches and canopies. We hypothesized that (i) among canopy tree species sharing similar light environments, deciduous trees will have more evenly spaced within-twig leaf distribution patterns compared with evergreen trees (because deciduous species tend to higher metabolic demands than evergreen species and hence require more light), and that (ii) shade-adapted evergreen species will have more evenly spaced patterns compared with sun-adapted evergreen ones (because shade-adapted species are generally light-limited). We tested these hypotheses by measuring morphological traits (i.e., internode length, leaf area, lamina mass per area, LMA; and leaf and twig inclination angles to the horizontal) and physiological traits (i.e., light-saturated net photosynthetic rates, Amax; light saturation points, LSP; and light compensation points, LCP), and calculated the 'evenness' of within-twig leaf distribution patterns as the coefficient of variation (CV; the higher the CV, the less evenly spaced leaves) of within-twig internode length for 9 deciduous canopy tree species, 15 evergreen canopy tree species, 8 shade-adapted evergreen shrub species and 12 sun-adapted evergreen shrub species in a subtropical broad-leaved rainforest in eastern China. Coefficient of variation was positively correlated with large LMA and large leaf and twig inclination angles, which collectively specify a typical trait combination adaptive to low light interception, as indicated by both ordinary regression and phylogenetic generalized least squares analyses. These relationships were also valid within the evergreen tree species group (which had the largest sample size). Consistent with our hypothesis, in the canopy layer, deciduous species (which were characterized by high LCP, LSP and

  10. Seasonal Habitat Patterns of Japanese Common Squid (Todarodes Pacificus Inferred from Satellite-Based Species Distribution Models

    Directory of Open Access Journals (Sweden)

    Irene D. Alabia

    2016-11-01

    Full Text Available The understanding of the spatio-temporal distributions of the species habitat in the marine environment is central to effectual resource management and conservation. Here, we examined the potential habitat distributions of Japanese common squid (Todarodes pacificus in the Sea of Japan during a four-year period. The seasonal patterns of preferential habitat were inferred from species distribution models, built using squid occurrences detected from night-time visible images and remotely-sensed environmental factors. The predicted squid habitat (i.e., areas with high habitat suitability revealed strong seasonal variability, characterized by a reduction of potential habitat, confined off of the southern part of the basin during the winter–spring period (December–May. Apparent expansion of preferential habitat occurred during summer–autumn months (June–November, concurrent with the formation of highly suitable habitat patches in certain regions of the Sea of Japan. These habitat distribution patterns were in response to changes in oceanographic conditions and synchronous with seasonal migration of squid. Moreover, the most important variables regulating the spatio-temporal patterns of suitable habitat were sea surface temperature, depth, sea surface height anomaly, and eddy kinetic energy. These variables could affect the habitat distributions through their impacts on growth and survival of squid, local nutrient transport, and the availability of favorable spawning and feeding grounds.

  11. More about the geographical pattern of distribution of the genus Pseudouroplectes Lourenço, 1995 (Scorpiones: Buthidae) from Madagascar.

    Science.gov (United States)

    Lourenço, Wilson R; Wilmé, Lucienne; Waeber, Patrick O

    2016-01-01

    The genus Pseudouroplectes Lourenço, 1995 (Buthidae) remains among the less speciose Malagasy genera and all the known species are extremely rare. A new species is described from the dry forests in the Tsingy formations of the National Park Bemaraha, extending the distribution of the genus further north. Once again, the single holotype specimen was obtained by extraction with the use of Berlese system. With the description of the new species, the distributional pattern of this genus is confirmed for dry forest formations from the south to the middle of the island; however, for the first time the group's distribution overlaps that of another micro-scorpion genus, Microcharmus Lourenço, 1995. The distribution patterns of the humicolous micro-scorpions endemic to Madagascar are considered to further explore the "Neogrosphus rule" as a possible explanation of global species distribution patterns in changing environments. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  12. Comparative demography of two co-occurring Linum species with different distribution patterns.

    Science.gov (United States)

    Münzbergová, Z

    2013-11-01

    Understanding similarities and differences in population dynamics of closely related species is a key prerequisite in attempts to apply knowledge obtained in one species to another species, e.g., for the purpose of predicting future fate of populations of various rare species. It can be expected that species will have similar population dynamics if they are closely related and share similar habitats. Contrasting population sizes and distribution patterns may, however, indicate that the population dynamics will be different. To understand similarities and differences in population dynamics of closely related species, I studied demography of two congeneric endangered species, Linum flavum and L. tenuifolium co-occurring in dry grasslands. Linum flavum occurs with a lower number of large populations, while L. tenuifolium occurs as a large number of small populations. The results showed that L. flavum had higher population growth rates, relied more on survival and growth and its populations were more persistent. In contrast, populations of L. tenuifolium were more prone to extinction and frequent recolonisation was necessary for their survival in the landscape. This was in accordance with observed population sizes of the two species and their frequency in the landscape. The results indicate that despite being closely related and occurring in the same habitat types, the two Linum species have different growth strategies. The strong differences in population dynamics between the two species suggest that similarity in population sizes and frequency of the species in the landscape may be more important when attempting to transfer knowledge between species than is taxonomic relatedness. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. [Species-abundance distribution patterns along succession series of Phyllostachys glauca forest in a limestone mountain].

    Science.gov (United States)

    Shi, Jian-min; Fan, Cheng-fang; Liu, Yang; Yang, Qing-pei; Fang, Kai; Fan, Fang-li; Yang, Guang-yao

    2015-12-01

    To detect the ecological process of the succession series of Phyllostachys glauca forest in a limestone mountain, five niche models, i.e., broken stick model (BSM), niche preemption model (NPM), dominance preemption model (DPM), random assortment model (RAM) and overlap- ping niche model (ONM) were employed to describe the species-abundance distribution patterns (SDPs) of 15 samples. χ² test and Akaike information criterion (AIC) were used to test the fitting effects of the five models. The results showed that the optimal SDP models for P. glauca forest, bamboo-broadleaved mixed forest and broadleaved forest were DPM (χ² = 35.86, AIC = -69.77), NPM (χ² = 1.60, AIC = -94.68) and NPM (χ² = 0.35, AIC = -364.61), respectively. BSM also well fitted the SDP of bamboo-broadleaved mixed forest and broad-leaved forest, while it was unsuitable to describe the SDP of P. glauca forest. The fittings of RAM and ONM in the three forest types were all rejected by the χ² test and AIC. With the development of community succession from P. glauca forest to broadleaved forest, the species richness and evenness increased, and the optimal SDP model changed from DPM to NPM. It was inferred that the change of ecological process from habitat filtration to interspecific competition was the main driving force of the forest succession. The results also indicated that the application of multiple SDP models and test methods would be beneficial to select the best model and deeply understand the ecological process of community succession.

  14. Pattern and distribution of pedestrian injuries in fatal road traffic accidental cases in Dharan, Nepal.

    Science.gov (United States)

    Mandal, Birendra Kumar; Yadav, Biswa Nath

    2014-07-01

    Road traffic injuries are one of the leading causes of death in the world. The present study aims at evaluation of pattern and distribution of injuries among pedestrians thereby planning successful measures to minimize fatalities. The present study was conducted in the Department of Forensic Medicine and Toxicology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. This study included 50 cases of pedestrian victims of fatal road traffic accident, brought for medico-legal postmortem examination. Highest number (17 or 21.3%) of fatalities occurred in the 41-50 years age group followed by the age group 31-40 years (15 or 18.7%). Male victims outnumbered female resulting in male to female ratio of 1.8:1. Most of the pedestrians were illiterate (26 or 32.5%) followed by those who were educated up to primary school (14 or 17.5%). Nearly half of the cases (38 or 47.5%), four or more wheelers - heavy vehicles - were involved. Fracture was the most common type of injuries (55 or 28.9%) followed by laceration (50 or 26.3%). In 44 (55%) cases, primary impact injuries were noted, secondary impact injuries in 55 (68.7%) cases, and secondary injuries in 62 (77.5%) cases. More than one-fourth (22 or 27.5%) of the deaths were due to pelvic and extremities injuries. Pedestrians, people who travel by foot, wheelchair, stroller, or similar means, are most vulnerable users of the road. Before head out on foot for a stroll, power walk, or errand, there are important safety tips to remember. A greater awareness about traffic rules will go a long way in curbing the incidence of fatal pedestrian accidents.

  15. A geomorphic analysis of Sinai's drainage pattern. Evidence for interpreting the distribution of uplift?

    Science.gov (United States)

    Oswald, Angela; Stüwe, Kurt; Hanke, Gustav

    2013-04-01

    A variety of quantitative geomorphologic methods have proven useful to infer aspects of the interplay between tectonics and surface processes and have been applied to various regions in the world. For example, quantitative analysis of drainage systems may be used to investigate the formation of mountain belts where the exposure of bedrock can be linked with tectonic processes. Sinai Peninsula, which is located at the northernmost Red Sea, shows what appears to be a fluvial landscape despite present aridity. Its geomorphology is suitable for a quantitative geomorphologic interpretation using a classic stream power approach. Geomorphologic parameters were derived through analysis of the ASTER digital elevation model (DEM). Steepness and concavity index were extracted from slope-area relationships along channel profiles. Although parameters like knickpoints along channels are typically controlled by complex mechanisms, they may be used to interpret different regimes of uplift. Sinuosity has been calculated from plan channel coordinates in order to differentiate between fluvial and fault dominated channels and channel segments. Because of possible overprinting of fluvial features by present day arid climate erosion and sedimentation processes, the DEM-based analysis needs to be supplemented with photographic images and field observations in order to assess the significance of the single parameter values. The spatial distribution of geomorphic parameter values is compared to the large scale topographic and slope pattern and correlated with the different tectonic regimes acting on Sinai, namely the divergent rifting of the Gulf of Suez in the West and the strike slip dominated opening of the Gulf of Aqaba, whereas Northern Sinai is tilted towards the Mediterranean.

  16. Spatio-temporal patterns of distribution of West Nile virus vectors in eastern Piedmont Region, Italy

    Directory of Open Access Journals (Sweden)

    Bisanzio Donal

    2011-12-01

    Full Text Available Abstract Background West Nile Virus (WNV transmission in Italy was first reported in 1998 as an equine outbreak near the swamps of Padule di Fucecchio, Tuscany. No other cases were identified during the following decade until 2008, when horse and human outbreaks were reported in Emilia Romagna, North Italy. Since then, WNV outbreaks have occurred annually, spreading from their initial northern foci throughout the country. Following the outbreak in 1998 the Italian public health authority defined a surveillance plan to detect WNV circulation in birds, horses and mosquitoes. By applying spatial statistical analysis (spatial point pattern analysis and models (Bayesian GLMM models to a longitudinal dataset on the abundance of the three putative WNV vectors [Ochlerotatus caspius (Pallas 1771, Culex pipiens (Linnaeus 1758 and Culex modestus (Ficalbi 1890] in eastern Piedmont, we quantified their abundance and distribution in space and time and generated prediction maps outlining the areas with the highest vector productivity and potential for WNV introduction and amplification. Results The highest abundance and significant spatial clusters of Oc. caspius and Cx. modestus were in proximity to rice fields, and for Cx. pipiens, in proximity to highly populated urban areas. The GLMM model showed the importance of weather conditions and environmental factors in predicting mosquito abundance. Distance from the preferential breeding sites and elevation were negatively associated with the number of collected mosquitoes. The Normalized Difference Vegetation Index (NDVI was positively correlated with mosquito abundance in rice fields (Oc. caspius and Cx. modestus. Based on the best models, we developed prediction maps for the year 2010 outlining the areas where high abundance of vectors could favour the introduction and amplification of WNV. Conclusions Our findings provide useful information for surveillance activities aiming to identify locations where the

  17. Species diversity and distribution patterns of the ants of Amazonian Ecuador.

    Directory of Open Access Journals (Sweden)

    Kari T Ryder Wilkie

    Full Text Available Ants are among the most diverse, abundant and ecologically significant organisms on earth. Although their species richness appears to be greatest in the New World tropics, global patterns of ant diversity and distribution are not well understood. We comprehensively surveyed ant diversity in a lowland primary rainforest in Western Amazonia, Ecuador using canopy fogging, pitfall traps, baits, hand collecting, mini-Winkler devices and subterranean probes to sample ants. A total of 489 ant species comprising 64 genera in nine subfamilies were identified from samples collected in only 0.16 square kilometers. The most species-rich genera were Camponotus, Pheidole, Pseudomyrmex, Pachycondyla, Brachymyrmex, and Crematogaster. Camponotus and Pseudomyrmex were most diverse in the canopy, while Pheidole was most diverse on the ground. The three most abundant ground-dwelling ant genera were Pheidole, Solenopsis and Pyramica. Crematogaster carinata was the most abundant ant species in the canopy; Wasmannia auropunctata was most abundant on the ground, and the army ant Labidus coecus was the most abundant subterranean species. Ant species composition among strata was significantly different: 80% of species were found in only one stratum, 17% in two strata, and 3% in all three strata. Elevation and the number of logs and twigs available as nest sites were significant predictors of ground-dwelling ant species richness. Canopy species richness was not correlated with any ecological variable measured. Subterranean species richness was negatively correlated with depth in the soil. When ant species were categorized using a functional group matrix based on diet, nest-site preference and foraging ecology, the greatest diversity was found in Omnivorous Canopy Nesters. Our study indicates ant species richness is exceptionally high at Tiputini. We project 647-736 ant species in this global hotspot of biodiversity. Considering the relatively small area surveyed, this

  18. Species diversity and distribution patterns of the ants of Amazonian Ecuador.

    Science.gov (United States)

    Ryder Wilkie, Kari T; Mertl, Amy L; Traniello, James F A

    2010-10-01

    Ants are among the most diverse, abundant and ecologically significant organisms on earth. Although their species richness appears to be greatest in the New World tropics, global patterns of ant diversity and distribution are not well understood. We comprehensively surveyed ant diversity in a lowland primary rainforest in Western Amazonia, Ecuador using canopy fogging, pitfall traps, baits, hand collecting, mini-Winkler devices and subterranean probes to sample ants. A total of 489 ant species comprising 64 genera in nine subfamilies were identified from samples collected in only 0.16 square kilometers. The most species-rich genera were Camponotus, Pheidole, Pseudomyrmex, Pachycondyla, Brachymyrmex, and Crematogaster. Camponotus and Pseudomyrmex were most diverse in the canopy, while Pheidole was most diverse on the ground. The three most abundant ground-dwelling ant genera were Pheidole, Solenopsis and Pyramica. Crematogaster carinata was the most abundant ant species in the canopy; Wasmannia auropunctata was most abundant on the ground, and the army ant Labidus coecus was the most abundant subterranean species. Ant species composition among strata was significantly different: 80% of species were found in only one stratum, 17% in two strata, and 3% in all three strata. Elevation and the number of logs and twigs available as nest sites were significant predictors of ground-dwelling ant species richness. Canopy species richness was not correlated with any ecological variable measured. Subterranean species richness was negatively correlated with depth in the soil. When ant species were categorized using a functional group matrix based on diet, nest-site preference and foraging ecology, the greatest diversity was found in Omnivorous Canopy Nesters. Our study indicates ant species richness is exceptionally high at Tiputini. We project 647-736 ant species in this global hotspot of biodiversity. Considering the relatively small area surveyed, this region of western

  19. Seasonality and Distribution Pattern of Brown Marmorated Stink Bug (Hemiptera: Pentatomidae) in Virginia Vineyards.

    Science.gov (United States)

    Basnet, S; Kuhar, T P; Laub, C A; Pfeiffer, D G

    2015-08-01

    Brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a highly polyphagous invasive insect pest from eastern Asia that feeds on numerous fruit, vegetable, and field crops. Four commercial vineyards in Virginia were sampled in 2012 and 2013 to study the basic biology, seasonality, and distribution pattern of H. halys in vineyards. At each vineyard, two blocks were selected. Weekly 3-min timed count visual samplings were performed in border and interior sections from late May until mid-September. Overwintering adult bugs were first detected in vineyards in May; however, the timing of first detection differed among vineyards. Egg masses were found primarily in June and July, and were usually found on the lower surface of grape leaves, although they were occasionally on the upper leaf surface, on the berry, or on the rachis. All developmental stages of H. halys were found in vineyards, suggesting that grape can serve as a reproductive host for H. halys. Substantial variation in H. halys densities was found among vineyards and throughout the growing season. The first instars were found on egg masses and after molting, dispersed throughout the grape vines. The date on which the first egg mass was collected was considered as a biofix. Based on a degree-day model, there were sufficient degree-days for completion of a generation in Virginia vineyards. Significantly higher numbers of H. halys were collected in border sections compared with interior sections. These results are discussed in relation to the potential pest status of H. halys in vineyards and implications for possible control strategies. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Pattern of Spatial Distribution and Temporal Variation of Atmospheric Pollutants during 2013 in Shenzhen, China

    Directory of Open Access Journals (Sweden)

    Xiaolin Xia

    2016-12-01

    Full Text Available Air pollution caused by atmospheric particulate and gaseous pollutants has drawn broad public concern globally. In this paper, the spatial-temporal distributions of major air pollutants in Shenzhen from March 2013 to February 2014 are discussed. In this study, ground-site monitoring data from 19 monitoring sites was used and spatial interpolation and spatial autocorrelation methods were applied to analyze both spatial and temporal characteristics of air pollutants in Shenzhen City. During the study period, the daily average concentrations of Particulate Matter (PM10 and PM2.5 ranged from 16–189 μg/m3 and 10–136 μg/m3, respectively, with 13 and 44 over-limit days, indicating that particulate matter was the primary air pollutant in Shenzhen. The highest PM occupation in the polluted air was observed in winter, indicating that fine particulate pollution was most serious in winter. Meanwhile, seasonal agglomeration patterns for six kinds of air pollutants showed that Guangming, Baoan, Nanshan, and the northern part of Longgang were the most polluted areas and PMs were their primary air pollutants. In addition, wind scale and rainfall played an important role in dissipating air pollutant in Shenzhen. The wind direction impacted the air pollution level in Shenzhen in multiple ways: the highest concentrations for all air pollutants all occurred on days with a northeast wind; the second highest ones appeared on the days with no wind. The concentrations on days with north-related winds are higher on average than those of days with south-related winds.

  1. Distributional patterns of decapod crustaceans in the circum-Mediterranean area during the Oligo-Miocene

    Science.gov (United States)

    Hyžný, Matúš

    2015-04-01

    During the Oligocene and Miocene, the circum-Mediterranean area was a complex network of (mostly) shallow marine basins. Significant biogeographic differentiation of this area has been documented (Harzhauser et al. 2007), mainly during the Miocene, when connections between Proto-Mediterranean, Paratethys and Proto-Indo-West Pacific were intermittently opening and closing. These seaways allowed migration of marine faunas. Distributional patterns has so far been discussed for several different animal groups, especially for molluscs (e.g. Studencka et al. 1998; Harzhauser et al. 2002, 2003, 2007). To test these patterns with decapod crustaceans, a database has been compiled including all previously published Oligocene and Miocene decapod occurrences and newly gathered data from examined material deposited in the institutional collections. Decapod associations have been significant components of marine habitats since the Mesozoic times with ever-increasing importance throughout the Cenozoic. Müller (1979) argued that brachyuran decapods are among the best zoogeographical indicators. Although decapods were used as such indicators before (e.g. Schweitzer 2001; Feldmann & Schweitzer 2006), no detailed analysis of the circum-Mediterranean taxa has been conducted so far. Based on proposed anti-estuarine circulation pattern, decapods originated in the Proto-Mediterranean, and migrated both into the North Sea and the Paratethys. Moreover, during the Early Miocene the Rhine Graben served as a connection between the North Sea and the Paratethys which enabled faunal exchange. The Middle Miocene Proto-Mediterranean and Paratethys decapod assemblages as taken together were relatively homogeneous, although distinct due to increasing rate of endemites in the Paratethys during the Miocene. The research has been supported by FWF: Lise Meitner Program M 1544-B25. References Feldmann R.M. & Schweitzer C.E. 2006: Paleobiogeography of Southern Hemisphere decapod Crustacea. J. Paleontol

  2. Predicting the distribution of spiral waves from cell properties in a developmental-path model of Dictyostelium pattern formation.

    Directory of Open Access Journals (Sweden)

    Daniel Geberth

    2009-07-01

    Full Text Available The slime mold Dictyostelium discoideum is one of the model systems of biological pattern formation. One of the most successful answers to the challenge of establishing a spiral wave pattern in a colony of homogeneously distributed D. discoideum cells has been the suggestion of a developmental path the cells follow (Lauzeral and coworkers. This is a well-defined change in properties each cell undergoes on a longer time scale than the typical dynamics of the cell. Here we show that this concept leads to an inhomogeneous and systematic spatial distribution of spiral waves, which can be predicted from the distribution of cells on the developmental path. We propose specific experiments for checking whether such systematics are also found in data and thus, indirectly, provide evidence of a developmental path.

  3. Both inherited susceptibility and environmental exposure determine the low-density lipoprotein-subfraction pattern distribution in healthy Dutch families

    Energy Technology Data Exchange (ETDEWEB)

    Graaf, J. de; Swinkels, D.W.; Haan, A.F.J. de; Demacker, P.N.M.; Stalenhoef, A.F.H. (University Hospital, Nijmegen (Netherlands))

    1992-12-01

    A lipoprotein profile characterized by a predominance of small, dense, low-density lipoprotein (LDL) particles has been associated with an increased risk of atherosclerosis. To investigate whether genetic factors are involved in determining this heavy LDL subfraction pattern, this study was undertaken with the aim of resolving the effects that major genes, multifactorial heritability, and environmental exposures have on the LDL subfraction pattern. In a random sample of 19 healthy Dutch families including 162 individuals, the distribution of the LDL subfraction pattern was determined by density gradient ultracentrifugation. For each subject a specific LDL subfraction profile was observed, characterized by the relative contribution of the three major LDL subfractions - LDL1 (d = 1.030-1.033 g/ml), LDL2 (d = 1.033-1.040 g/ml), and LDL3 (d = 1.040-1.045 g/ml) - to total LDL. A continuous variable, parameter K, was defined to characterize each individual LDL subfraction pattern. Complex segregation analysis of this quantitative trait, under a model which includes a major locus, polygenes, and both common and random environment, was applied to analyze the distribution of the LDL subfraction pattern in these families. The results indicate that the LDL subfraction pattern, described by parameter K, is controlled by a major autosomal, highly penetrant, recessive allele with a population frequency of .19 and an additional multifactorial inheritance component. The results indicate that genetic influences as well as environmental exposure, sex, age and hormonal status in women are important in determining the distribution of the LDL subfraction patterns in this population and that these influences may contribute to the explanation of familial clustering of coronary heart disease. 40 refs., 3 figs., 8 tabs.

  4. Pattern of tick aggregation on mice: larger than expected distribution tail enhances the spread of tick-borne pathogens.

    Directory of Open Access Journals (Sweden)

    Luca Ferreri

    2014-11-01

    Full Text Available The spread of tick-borne pathogens represents an important threat to human and animal health in many parts of Eurasia. Here, we analysed a 9-year time series of Ixodes ricinus ticks feeding on Apodemus flavicollis mice (main reservoir-competent host for tick-borne encephalitis, TBE sampled in Trentino (Northern Italy. The tail of the distribution of the number of ticks per host was fitted by three theoretical distributions: Negative Binomial (NB, Poisson-LogNormal (PoiLN, and Power-Law (PL. The fit with theoretical distributions indicated that the tail of the tick infestation pattern on mice is better described by the PL distribution. Moreover, we found that the tail of the distribution significantly changes with seasonal variations in host abundance. In order to investigate the effect of different tails of tick distribution on the invasion of a non-systemically transmitted pathogen, we simulated the transmission of a TBE-like virus between susceptible and infective ticks using a stochastic model. Model simulations indicated different outcomes of disease spreading when considering different distribution laws of ticks among hosts. Specifically, we found that the epidemic threshold and the prevalence equilibria obtained in epidemiological simulations with PL distribution are a good approximation of those observed in simulations feed by the empirical distribution. Moreover, we also found that the epidemic threshold for disease invasion was lower when considering the seasonal variation of tick aggregation.

  5. Testing the enemy release hypothesis: abundance and distribution patterns of helminth communities in grey mullets (Teleostei: Mugilidae) reveal the success of invasive species.

    Science.gov (United States)

    Sarabeev, Volodimir; Balbuena, Juan Antonio; Morand, Serge

    2017-09-01

    The abundance and aggregation patterns of helminth communities of two grey mullet hosts, Liza haematocheilus and Mugil cephalus, were studied across 14 localities in Atlantic and Pacific marine areas. The analysis matched parasite communities of (i) L. haematocheilus across its native and introduced populations (Sea of Japan and Sea of Azov, respectively) and (ii) the introduced population of L. haematocheilus with native populations of M. cephalus (Mediterranean, Azov-Black and Japan Seas). The total mean abundance (TMA), as a feature of the infection level in helminth communities, and slope b of the Taylor's power law, as a measure of parasite aggregation at the infra and component-community levels, were estimated and compared between host species and localities using ANOVA. The TMA of the whole helminth community in the introduced population of L. haematocheilus was over 15 times lower than that of the native population, but the difference was less pronounced for carried (monogeneans) than for acquired (adult and larval digeneans) parasite communities. Similar to the abundance pattern, the species distribution in communities from the invasive population of L. haematocheilus was less aggregated than from its native population for endoparasitic helminths, including adult and larval digeneans, while monogeneans showed a similar pattern of distribution in the compared populations of L. haematocheilus. The aggregation level of the whole helminth community, endoparasitic helminths, adult and larval digeneans was lower in the invasive host species in comparison with native ones as shown by differences in the slope b. An important theoretical implication from this study is that the pattern of parasite aggregation may explain the success of invasive species in ecosystems. Because the effects of parasites on host mortality are likely dose-dependent, the proportion of susceptible host individuals in invasive species is expected to be lower, as the helminth distribution in

  6. Distributed Storage Algorithm for Geospatial Image Data Based on Data Access Patterns

    OpenAIRE

    Shaoming Pan; Yongkai Li; Zhengquan Xu; Yanwen Chong

    2015-01-01

    Declustering techniques are widely used in distributed environments to reduce query response time through parallel I/O by splitting large files into several small blocks and then distributing those blocks among multiple storage nodes. Unfortunately, however, many small geospatial image data files cannot be further split for distributed storage. In this paper, we propose a complete theoretical system for the distributed storage of small geospatial image data files based on mining the access pa...

  7. An analysis of the horizontal burrow morphology of the oriental mole cricket (Gryllotalpa orientalis) and the distribution pattern of surface vegetation

    National Research Council Canada - National Science Library

    Endo, C

    2008-01-01

    .... The burrowing patterns of the oriental mole cricket (Gryllotalpa orientalis Brumeister, 1838) (Orthoptera: Gryllotalpidae) were investigated based on analyses of the relation between burrow morphology and plant distribution...

  8. Inferring processes from spatial patterns: the role of directional and non-directional forces in shaping fish larvae distribution in a freshwater lake system.

    Directory of Open Access Journals (Sweden)

    Andrea Bertolo

    Full Text Available Larval dispersal is a crucial factor for fish recruitment. For fishes with relatively small-bodied larvae, drift has the potential to play a more important role than active habitat selection in determining larval dispersal; therefore, we expect small-bodied fish larvae to be poorly associated with habitat characteristics. To test this hypothesis, we used as model yellow perch (Perca flavescens, whose larvae are among the smallest among freshwater temperate fishes. Thus, we analysed the habitat association of yellow perch larvae at multiple spatial scales in a large shallow fluvial lake by explicitly modelling directional (e.g. due to water currents and non-directional (e.g. due to aggregation spatial patterns. This allowed us to indirectly assess the relative roles of drift (directional process and potential habitat choice on larval dispersal. Our results give weak support to the drift hypothesis, whereas yellow perch show a strong habitat association at unexpectedly small sizes, when compared to other systems. We found consistent non-directional patterns in larvae distributions at both broad and medium spatial scales but only few significant directional components. The environmental variables alone (e.g. vegetation generally explained a significant and biologically relevant fraction of the variation in fish larvae distribution data. These results suggest that (i drift plays a minor role in this shallow system, (ii larvae display spatial patterns that only partially covary with environmental variables, and (iii larvae are associated to specific habitats. By suggesting that habitat association potentially includes an active choice component for yellow perch larvae, our results shed new light on the ecology of freshwater fish larvae and should help in building more realistic recruitment models.

  9. Spatial and temporal distribution patterns of the silver mojarra Eucinostomus argenteus (Perciformes: Gerreidae) in a tropical semi-enclosed bay.

    Science.gov (United States)

    Corrêa, B; Vianna, M

    2016-07-01

    This study determined the spatial and temporal distributions of the silver mojarra Eucinostomus argenteus (Perciformes: Gerreidae), one of the most abundant teleost species in bays and estuaries. Sampling was conducted from July 2005 to June 2007. The species was captured on all sampling dates and at six of the seven sampling stations. Approximately 80% of the individuals were below the size of first sexual maturity (12·0 cm total length, LT ). Although the spatial distribution of juveniles and adults differed throughout the study period, the environmental variables measured explained only a small part of their distribution. The recruitment period occurred during the first part of each year. Despite the high pollution levels in Guanabara Bay, this coastal system plays an important role as a nursery ground and for the growth of E. argenteus. © 2015 The Fisheries Society of the British Isles.

  10. Decapod crustacean larval communities in the Balearic Sea (western Mediterranean): Seasonal composition, horizontal and vertical distribution patterns

    Science.gov (United States)

    Torres, Asvin P.; Dos Santos, Antonina; Balbín, Rosa; Alemany, Francisco; Massutí, Enric; Reglero, Patricia

    2014-10-01

    Decapod crustaceans are the main target species of deep water bottom trawl fisheries in the Balearic Sea but little is known about their larval stages. This work focuses on the species composition of the decapod larval community, describing the main spatio-temporal assemblages and assessing their vertical distribution. Mesozooplankton sampling was carried out using depth-stratified sampling devices at two stations located over the shelf break and the mid slope, in the north-western and southern Mallorca in late autumn 2009 and summer 2010. Differences among decapod larvae communities, in terms of composition, adult's habitat such as pelagic or benthic, and distribution patterns were observed between seasons, areas and station. Results showed that for both seasons most species and developmental stages aggregated within the upper water column (above 75 m depth) and showed higher biodiversity in summer compared to late autumn. Most abundant species were pelagic prawns (e.g., Sergestidae) occurring in both seasons and areas. The larval assemblages' distributions were different between seasonal hydrographic scenarios and during situations of stratified and non-stratified water column. The vertical distribution patterns of different larval developmental stages in respect to the adult's habitat were analyzed in relation to environmental variables. Fluorescence had the highest explanatory power. Four clearly different vertical patterns were identified: two corresponding to late autumn, which were common for all the main larval groups and other two in summer, one corresponding to larvae of coastal benthic and the second to pelagic species larvae.

  11. Community Structure and Distribution Pattern of Intertidal Invertebrate Macrofauna at Some Anthropogenically Influenced Coasts of Kathiawar Peninsula (India

    Directory of Open Access Journals (Sweden)

    Poonam Bhadja

    2014-01-01

    Full Text Available Present communication reports the community structure and distribution pattern of intertidal invertebrate macrofauna at four shores of the Kathiawar peninsular coastline off the Arabian Sea (India. The selected shores have different levels of human activities. Present report tests three hypotheses; that is, (i distribution of invertebrate macrofauna in these shores is influenced by space and time, (ii abiotic factors have a profound influence on the distribution pattern of intertidal macrofaunal assemblages, and (iii human activities influence the community structure of the intertidal invertebrate macrofauna at these shores. To test these hypotheses, spatiotemporal variations in different ecological indices were studied. A total of 60 species from six phyla were considered for the study. High species diversity was recorded during winter and monsoon seasons in almost all the shores studied. It was also evident that a few environmental factors had a cumulative influence on the distribution pattern of intertidal macrofauna. Significant spatial variations in the species diversity and evenness were also observed. Though the shores studied have similar coast characteristics and climatic conditions, they face different levels of human activities. Therefore, the observed variations in the intertidal faunal assemblage were possibly caused by anthropogenic stress.

  12. Distribution of coronoid fracture lines by specific patterns of traumatic elbow instability

    NARCIS (Netherlands)

    Mellema, Jos J.; Doornberg, Job N.; Dyer, George S. M.; Ring, David

    2014-01-01

    To determine if specific coronoid fractures relate to specific overall traumatic elbow instability injury patterns and to depict any relationship on fracture maps and heat maps. We collected 110 computed tomography (CT) studies from patients with coronoid fractures. Fracture types and pattern of

  13. The study on the effect of pattern density distribution on the STI CMP process

    Science.gov (United States)

    Sub, Yoon Myung; Hian, Bernard Yap Tzen; Fong, Lee It; Anak, Philip Menit; Minhar, Ariffin Bin; Wui, Tan Kim; Kim, Melvin Phua Twang; Jin, Looi Hui; Min, Foo Thai

    2017-08-01

    The effects of pattern density on CMP characteristics were investigated using specially designed wafer for the characterization of pattern-dependencies in STI CMP [1]. The purpose of this study is to investigate the planarization behavior based on a direct STI CMP used in cerium (CeO2) based slurry system in terms of pattern density variation. The minimal design rule (DR) of 180nm generation technology node was adopted for the mask layout. The mask was successfully applied for evaluation of a cerium (CeO2) abrasive based direct STI CMP process. In this study, we described a planarization behavior of the loading-effects of pattern density variation which were characterized with layout pattern density and pitch variations using masks mentioned above. Furthermore, the characterizing pattern dependent on the variations of the dimensions and spacing features, in thickness remaining after CMP, were analyzed and evaluated. The goal was to establish a concept of library method which will be used to generate design rules reducing the probability of CMP-related failures. Details of the characterization were measured in various layouts showing different pattern density ranges and the effects of pattern density on STI CMP has been discussed in this paper.

  14. [Faunal characteristics and distribution pattern of crustaceans in the vicinity of Pearl River estuary].

    Science.gov (United States)

    Huang, Zi-Rong; Sun, Dian-Rong; Chen, Zuo-Zhi; Zhang, Han-Hua; Wang, Xue-Hui; Wang, Yue-Zhong; Fang, Hong-Da; Dong, Yan-Hong

    2009-10-01

    Based on the data of bottom trawl surveys in the vicinity of Pearl River estuary in August (summer), October (autumn), December (winter) 2006, and April (spring) 2007, the faunal characteristics and distribution pattern of crustaceans were analyzed. A total of 54 species belonging to 25 genera, 17 families, and 2 orders were collected, including 22 species of shrimps, 22 species of crabs, and 10 species of squills. Most of the crustaceans were tropical-subtropical warm-water species, a few of them were eurythermal species, and no warm-water and cold-water species occurred. Euryhaline species were most abundant, followed by halophile species, and the low-salinity species were the least. Most of the crustacean species belonged to the fauna of Indian Ocean-western Pacific Ocean. The faunal assemblages were closer to those of the East China Sea, Philippine Sea, Indonesia Sea, and the Japan Sea, and estranger with those of the Yellow Sea, Bohai Sea, and Korea Sea. The dominant species were Metapenaeus joyner, Oratosquilla oratoria, Charybdis miles, Portunus sanguinolentus, Harpiosquilla harpax, Charybdis feriatus, Charybdis japonica, Oratosquilla nepa, Solenocera crassicornis, Portunus trituberculatus, and Calappa philargius. The crustaceans had the largest species number (33) in autumn and the least one (26) in spring, and the highest stock density at the water depth of < 40 m, especially at 10-20 m. The average stock density of the crustaceans was estimated to be 99.60 kg x km(-2), with the highest (198.93 kg x km(-2)) in summer and the lowest (42.35 kg x km(-2)) in spring. Of the 3 species groups, crabs had the highest stock density (41.81 kg x km(-2)), followed by shrimps (38.91 kg x km(-2)), and squills (18.88 kg x km(-2)). The stock densities of the 3 species groups showed an obvious seasonal variation. Shrimps had the highest stock density (120.32 kg x km(-2)) in summer and the lowest density (0.67 kg x km(-2)) in spring, while crabs and squills had the highest

  15. Intra-articular distribution pattern after ultrasound-guided injections in wrist joints of patients with rheumatoid arthritis

    DEFF Research Database (Denmark)

    Boesen, Mikael; Jensen, Karl Erik; Torp-Pedersen, Søren

    2007-01-01

    OBJECTIVE: To investigate the distribution of an ultrasound-guided intra-articular (IA) injection in the wrist joint of patients with rheumatoid arthritis (RA). METHODS: An ultrasound-guided IA drug injection into the wrist joint was performed in 17 patients with 1 ml methylprednisolone (40 mg....../ml), 0.5 ml Lidocaine (5mg/ml) and 0.15 ml gadolinium (Omniscan 0.5 mmol/ml). The drug solution was placed in the central proximal part of the wrist between the distal radius and the lunate bone. Coronal and axial MRI sequences were performed after the injection to visualize the distribution. Carpal...... with the MRI OMERACT synovitis score (r=0.60, p=0.014), but not with the erosions, bonemarrow oedema scores or any clinical parameters. CONCLUSION: The distribution of contrast on MRI showed patient specific and random patterns after IA injections in active RA wrist joints. The degree of distribution increased...

  16. Development of a pattern to measure multiscale deformation and strain distribution via in situ FE-SEM observations.

    Science.gov (United States)

    Tanaka, Y; Naito, K; Kishimoto, S; Kagawa, Y

    2011-03-18

    We investigated a method for measuring deformation and strain distribution in a multiscale range from nanometers to millimeters via in situ FE-SEM observations. A multiscale pattern composed of a grid as well as random and nanocluster patterns was developed to measure the localized deformation at the specimen surface. Our in situ observations of a carbon fiber-reinforced polymer matrix composite with a hierarchical microstructure subjected to loading were conducted to identify local deformation behaviors at various boundaries. We measured and analyzed the multiscale deformation and strain localizations during various stages of loading.

  17. Urodynamic pattern distribution among aged male patients with lower urinary tract symptoms suggestive of bladder outlet obstruction.

    Science.gov (United States)

    Xu, Danfeng; Cui, Xingang; Qu, Chuangyu; Yin, Lei; Wang, Cunzhou; Chen, Jie

    2014-03-01

    To develop a urodynamic study (UDS) pattern system for aged male patients who complained of non-neurogenic lower urinary tract symptoms (LUTS) to create a reference guideline for their diagnosis and treatment by a retrospective analysis. A retrospective analysis of UDS data was carried out in 1984 male patients neurologically intact with symptoms suggestive of bladder outlet obstruction (BOO) aged older than 45 years (2002-2013). On the basis of their UDS characteristic findings, the patients were classified into 1 of 7 subgroups: equivocal or mild BOO with sphincter synergia with or without idiopathic detrusor overactivity (pattern A); equivocal or mild BOO with idiopathic sphincter overactivity (B); classic BOO with sphincter synergia (C) or overactivity (D); BOO with only detrusor low compliance (E); BOO with both detrusor underactivity and low compliance (F); and equivocal BOO with detrusor underactivity (G). The follow-up data were reviewed and analyzed thereafter. The feasibility and rationality of this system were confirmed. The distribution of 7 patterns (pattern, case number, %) was A 158, 8%; B 59, 3%; C 1059, 53.3%; D 277, 14%; E 120, 6%; F 93, 4.7%; and G 218, 11%. A-G numbers in pattern C, D, and E were 103.1-141.4, higher than other patterns (P <.001), and functional pressure lengths of pattern C and D were 7.0-7.2 cm, longer than other patterns (P <.001). A practical UDS pattern system for aged male patients with lower urinary tract symptoms suggestive of BOO was constructed, which can be used to optimize the diagnosis and treatment of these patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Spatial patterns in the distribution of kimberlites: relationship to tectonic processes and lithosphere structure

    DEFF Research Database (Denmark)

    Chemia, Zurab; Artemieva, Irina; Thybo, Hans

    2015-01-01

    Since the discovery of diamonds in kimberlite-type rocks more than a century ago, a number of theories regarding the processes involved in kimberlite emplacement have been put forward to explain the unique properties of kimberlite magmatism. Geological data suggests that pre-existing lithosphere ...

  19. Spatial patterns in the distribution of kimberlites: relationship to tectonic processes and lithosphere structure

    DEFF Research Database (Denmark)

    Chemia, Zurab; Artemieva, Irina; Thybo, Hans

    Since the discovery of diamonds in kimberlite-type rocks more than a century ago, a number of theories regarding the processes involved in kimberlite emplacement have been put forward to explain the unique properties of kimberlite magmatism. Geological data suggests that pre-existing lithosphere ...

  20. Exact distribution of a pattern in a set of random sequences generated by a Markov source: applications to biological data

    Directory of Open Access Journals (Sweden)

    Regad Leslie

    2010-01-01

    Full Text Available Abstract Background In bioinformatics it is common to search for a pattern of interest in a potentially large set of rather short sequences (upstream gene regions, proteins, exons, etc.. Although many methodological approaches allow practitioners to compute the distribution of a pattern count in a random sequence generated by a Markov source, no specific developments have taken into account the counting of occurrences in a set of independent sequences. We aim to address this problem by deriving efficient approaches and algorithms to perform these computations both for low and high complexity patterns in the framework of homogeneous or heterogeneous Markov models. Results The latest advances in the field allowed us to use a technique of optimal Markov chain embedding based on deterministic finite automata to introduce three innovative algorithms. Algorithm 1 is the only one able to deal with heterogeneous models. It also permits to avoid any product of convolution of the pattern distribution in individual sequences. When working with homogeneous models, Algorithm 2 yields a dramatic reduction in the complexity by taking advantage of previous computations to obtain moment generating functions efficiently. In the particular case of low or moderate complexity patterns, Algorithm 3 exploits power computation and binary decomposition to further reduce the time complexity to a logarithmic scale. All these algorithms and their relative interest in comparison with existing ones were then tested and discussed on a toy-example and three biological data sets: structural patterns in protein loop structures, PROSITE signatures in a bacterial proteome, and transcription factors in upstream gene regions. On these data sets, we also compared our exact approaches to the tempting approximation that consists in concatenating the sequences in the data set into a single sequence. Conclusions Our algorithms prove to be effective and able to handle real data sets with

  1. Exact distribution of a pattern in a set of random sequences generated by a Markov source: applications to biological data

    Science.gov (United States)

    2010-01-01

    Background In bioinformatics it is common to search for a pattern of interest in a potentially large set of rather short sequences (upstream gene regions, proteins, exons, etc.). Although many methodological approaches allow practitioners to compute the distribution of a pattern count in a random sequence generated by a Markov source, no specific developments have taken into account the counting of occurrences in a set of independent sequences. We aim to address this problem by deriving efficient approaches and algorithms to perform these computations both for low and high complexity patterns in the framework of homogeneous or heterogeneous Markov models. Results The latest advances in the field allowed us to use a technique of optimal Markov chain embedding based on deterministic finite automata to introduce three innovative algorithms. Algorithm 1 is the only one able to deal with heterogeneous models. It also permits to avoid any product of convolution of the pattern distribution in individual sequences. When working with homogeneous models, Algorithm 2 yields a dramatic reduction in the complexity by taking advantage of previous computations to obtain moment generating functions efficiently. In the particular case of low or moderate complexity patterns, Algorithm 3 exploits power computation and binary decomposition to further reduce the time complexity to a logarithmic scale. All these algorithms and their relative interest in comparison with existing ones were then tested and discussed on a toy-example and three biological data sets: structural patterns in protein loop structures, PROSITE signatures in a bacterial proteome, and transcription factors in upstream gene regions. On these data sets, we also compared our exact approaches to the tempting approximation that consists in concatenating the sequences in the data set into a single sequence. Conclusions Our algorithms prove to be effective and able to handle real data sets with multiple sequences, as well

  2. Patterns in the Distribution of Digital Games via BitTorrent

    DEFF Research Database (Denmark)

    Drachen, Anders; Veitch, Rob

    2013-01-01

    The distribution of illegal copies of computer games via digital networks forms the centre in one of the most heated debates in the international games environment, but there is minimal objective information available. Here the results of a large-scale, open-method analysis of the distribution of...

  3. Patterns in the distribution of digital games via BitTorrent

    DEFF Research Database (Denmark)

    Drachen, Anders; Veitch, Robert W. D.

    2013-01-01

    The distribution of illegal copies of computer games via digital networks forms the centre in one of the most heated debates in the international games environment, but there is minimal objective information available. Here the results of a large-scale, open-method analysis of the distribution of...

  4. Temporal and spatial patterns in the distribution of squid Loligo spp ...

    African Journals Online (AJOL)

    A Geographic Information System (GIS) was used to test hypotheses regarding the spatial distribution of the squid Loligo forbesi and Loligo vulgaris vulgaris in the northern North-East Atlantic during the years 1989-1994. Loligo spp. were present throughout coastal waters of the United Kingdom, but distribution was patchy ...

  5. Effects of resource distribution patterns on ungulate foraging behaviour: a modelling approach.

    NARCIS (Netherlands)

    Wallis de Vries, M.F.

    1996-01-01

    The food resources of forest ungulates typically are patchily distributed. Research on foraging behaviour has often focused on habitat selection but has rarely taken into account the influence of the spatial distribution of different food patches in two dimensions. However, especially when

  6. Contrasting genetic diversity patterns in two sister kelp species co-distributed along the coast of Brittany, France.

    Science.gov (United States)

    Robuchon, Marine; Le Gall, Line; Mauger, Stéphane; Valero, Myriam

    2014-06-01

    We investigated patterns of genetic structure in two sister kelp species to explore how distribution width along the shore, zonation, latitudinal distribution and historical factors contribute to contrasting patterns of genetic diversity. We implemented a hierarchical sampling scheme to compare patterns of genetic diversity and structure in these two kelp species co-distributed along the coasts of Brittany (France) using a total of 12 microsatellites, nine for Laminaria hyperborea and 11 for Laminaria digitata, of which eight amplified in both species. The genetic diversity and connectivity of L. hyperborea populations were greater than those of L. digitata populations in accordance with the larger cross-shore distribution width along the coast and the greater depth occupied by L. hyperborea populations in contrast to L. digitata populations. In addition, marginal populations showed reduced genetic diversity and connectivity, which erased isolation-by-distance patterns in both species. As L. digitata encounters its southern range limit in southern Brittany (SBr) while L. hyperborea extends down to mid-Portugal, it was possible to distinguish the effect of habitat continuity from range edge effects. We found that L. digitata did not harbour high regional diversity at its southern edge, as expected in a typical rear edge, suggesting that refuges from the last glacial maximum for L. digitata were probably not located in SBr, but most likely further north. For both species, the highest levels of genetic diversity were found in the Iroise Sea and Morlaix Bay, the two regions in which they are being currently harvested. Preserving genetic diversity of these two foundation species in these areas should, thus, be a priority for the management of this resource in Brittany. © 2014 John Wiley & Sons Ltd.

  7. Rainfall interception and distribution patterns of gross precipitation around an isolated Ficus benjamina tree in an urban area

    Science.gov (United States)

    Guevara-Escobar, A.; González-Sosa, E.; Véliz-Chávez, C.; Ventura-Ramos, E.; Ramos-Salinas, M.

    2007-02-01

    SummaryInterception of rainfall by urban trees can be an important component of urban landscapes. This work evaluated rainfall interception and distribution patterns of gross precipitation around the canopy of a single evergreen tree Ficus benjamina (L.). Nineteen individual storms occurring from July to October, 2005, were analyzed. Total precipitation for the studied period was 152 mm representing 46% of the annual precipitation. Rainfall was partitioned as follows: 38.1% throughfall, 2.4% stemflow, and 59.5% interception by the tree canopy. Canopy saturation was estimated at 1.5 mm using a linear relationship between throughfall and stemflow. Average time for saturation of canopy was 19.5 min. The screen effect was important and accounted for 18.7% of the interception losses by the tree canopy alone. A kriging model was used to explore spatial distribution patterns of rainfall and the screen effect around the projected crown. The results indicated that the tree modifies the precipitation pattern around the tree and suggested that these patterns were similar among events.

  8. The Association between Land-Use Distribution and Residential Patterns: the Case of Mixed Arab-Jewish Cities in Israel

    Directory of Open Access Journals (Sweden)

    Ran GOLDBLATT

    2014-06-01

    Full Text Available The emergence of GIS and the availability of high resolution geographic data have improved our ability to investigate the residential segregation in cities and to identify the temporal changes of the spatial phenomena. Using GIS, we have quantitatively and visually analyzed the correspondence between land-use distribution and Arab residential patterns and their changes in the period between 1983 and 2008 in five mixed Arab-Jewish Israeli cities. Results show a correspondence between the dynamics of Arab/Jewish residential patterns and the spatial distribution of various land-uses. Arab residential patterns diffused faster towards areas with relatively inferior land-uses than towards areas with more attractive land-uses, in which a gentrification process occurred. Moreover, large-scale non-residential land-uses act as spatial partitions that divide between Arab and Jewish residential areas. Understanding the association between the urban environment and residential patterns can help in formulating an appropriate social and spatial policy concerning planning of land-uses and design of the built environment in mixed cities.

  9. Distribution pattern of picoplankton carbon biomass linked to mesoscale dynamics in the southern gulf of Mexico during winter conditions

    Science.gov (United States)

    Linacre, Lorena; Lara-Lara, Rubén; Camacho-Ibar, Víctor; Herguera, Juan Carlos; Bazán-Guzmán, Carmen; Ferreira-Bartrina, Vicente

    2015-12-01

    In order to characterize the carbon biomass spatial distribution of autotrophic and heterotrophic picoplankton populations linked to mesoscale dynamics, an investigation over an extensive open-ocean region of the southern Gulf of Mexico (GM) was conducted. Seawater samples from the mixed layer were collected during wintertime (February-March 2013). Picoplankton populations were counted and sorted using flow cytometry analyses. Carbon biomass was assessed based on in situ cell abundances and conversion factors from the literature. Approximately 46% of the total picoplankton biomass was composed of three autotrophic populations (Prochlorococcus, Synechococcus, and pico-eukaryotes), while 54% consisted of heterotrophic bacteria populations. Prochlorococcus spp. was the most abundant pico-primary producer (>80%), and accounted for more than 60% of the total pico-autotrophic biomass. The distribution patterns of picoplankton biomass were strongly associated with the mesoscale dynamics that modulated the hydrographic conditions of the surface mixed layer. The main features of the carbon distribution pattern were: (1) the deepening of picoplankton biomass to layers closer to the nitracline base in anticyclonic eddies; (2) the shoaling of picoplankton biomass in cyclonic eddies, constraining the autoprokaryote biomasses to the upper layers, as well as accumulating the pico-eukaryote biomass in the cold core of the eddies; and (3) the increase of heterotrophic bacteria biomass in frontal regions between counter-paired anticyclonic and cyclonic eddies. Factors related to nutrient preferences and light conditions may as well have contributed to the distribution pattern of the microbial populations. The findings reveal the great influence of the mesoscale dynamics on the distribution of picoplankton populations within the mixed layer. Moreover, the significance of microbial components (especially Prochlorococcus) in the southern GM during winter conditions was revealed

  10. Distribution patterns of chaetognata, polychaeta, pteropoda and salpidae off south georgia and south orkney islands

    Directory of Open Access Journals (Sweden)

    Alina María Crelier

    2010-12-01

    Full Text Available The distribution pattern, frequency and density (ind./1000 m of different mesozooplankton species from the South Georgia Islands, South Orkney Islands and the Weddell-Scotia Confluence were analyzed using data obtained in 1994. The maximum densities of the species found were: Eukrohnia hamata (5330, Sagitta gazellae (1052, Clione limacina antarctica (450, Spongiobranchaea australis (375, Clio sulcata (100, Limacina helicina (4076 x 10³, Limacina retroversa (71 x 10(4, Pelagobia longicirrata (29170, Rhynchonereella bongraini (117, Tomopteris carpenterii (26, Tomopteris planktonis (498, Tomopteris septentrionales (498 and Salpa thompsoni (189. Species density and frequency decreased from South Georgia to the South Orkney Islands, recording intermediate values at the Weddell-Scotia Confluence. Species density in the South Orkney area seemed to be limited by variations in temperature and salinity. The southern area around South Georgia showed the highest density of species, probably due to the influence of the Southern Front of the Antarctic Circumpolar Current. The presence of species characteristic of sub-Antarctic waters such as L. retroversa in the Confluence area could be related to the southward movements of eddies that originate in the Polar Front.Foram analisados os padrões de distribuição, freqüência e densidade (ind. 1000 m de diferentes espécies de mesozooplâncton encontradas em torno das ilhas Georgias e Orcadas del Sur no verão de 1994. As densidades máximas apresentadas pelas espécies principais foram: Eukrohnia hamata (5330, Sagitta gazellae (1052, Clione limacina antarctica (450, Spongiobranchaea australis (375, Clio sulcata (100, Limacina helicina (4076 x 10³, Limacina retroversa (71 x 10(4; Pelagobia longicirrata (29170, Rhynchonereella bongraini (117, Tomopteris carpenterii (26, Tomopteris planktonis (498, Tomopteris septentrionales (498 y Salpa thompsoni (189. A densidade e freqüência das espécies diminuíram das

  11. Post mortem CT of intrahepatic gas distribution in twenty-seven victims of a flood: Patterns and timing.

    Science.gov (United States)

    Sapienza, Daniela; Bottari, Antonio; Gualniera, Patrizia; Asmundo, Alessio; Perri, Fabrizio; Gaeta, Michele

    2017-09-21

    We reported the results of post mortem computed tomography of the liver in 27 subjects dead simultaneously during a flood. The aim of our work was to identify the different patterns of post mortem intrahepatic gas distribution and the timing of its appearance. Although post mortem CT is the method of choice for the evaluation of gas distribution, controversies exist about the first site of appearance of intrahepatic gas (portal veins versus hepatic veins) as well as the timing and steps of intrahepatic gas spreading. In each subject we performed thin slice CT scanner (Somatom Definition, Siemens) and post processing of native CT images with Minimum Intensity Projection technique. Our results show that the first site of appearance of intrahepatic gas is portal veins. Gas in hepatic veins was never seen without the presence of the gas in portal vein. Gaseous cysts in hepatic parenchyma represent a further and usually more tardive pattern of intrahepatic gas distribution. In addition, we demonstrated that differences in timing of gas spreading was statistically significative for exclusive presence of portal veins gas before 48h as well as for complete substitution of hepatic parenchyma by cysts 64h after death. In conclusion, our work shows that the CT study of postmortem intrahepatic gas distribution could be a useful complementary tool both in demonstrating the mechanism of intrahepatic gas spreading and in estimating post mortem interval. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Circular distribution pattern of plant modulars and endophagous herbivory within tree crowns: the impact of roadside light conditions.

    Science.gov (United States)

    Dai, Xiao-Hua; Xu, Jia-Sheng; Ding, Xing-Lu

    2013-01-01

    The circular distributions of plant modulars (branches, leaves) and endophagous herbivory (mines, galls) were investigated within the crowns of four dominant Fagaceae trees in a subtropical evergreen broadleaf forest at Jiulianshan National Nature Reserve, Jiangxi, China. The hypothesis is that more plant modulars and more endophagous herbivory should occur in the crown area perpendicular to the roads. Circular statistical techniques were used to verify new patterns of the impact of roads on plants and insects. The results confirmed that the roadside light environments had larger impacts on the circular distribution patterns of plant modulars than those of leaf herbivores. For herbivores, the impact of light was larger on mine distribution than on gall distribution. The branches of all four tree species were concentrated in the direction perpendicular to the roads. In the preferred direction, branches were longer and higher. More leaves, more mines, and more galls were found surrounding the preferred branch direction. In general, leaf miners and leaf gallers preferred leaves in the sun over those in the shade; however, leaf gallers had a lower degree of preference for sun than leaf miners. Different endphagous insects also showed clear interspecific differences in sun/shade leaf selection.

  13. Spatial Patterns in Distribution of Kimberlites: Relationship to Tectonic Processes and Lithosphere Structure

    DEFF Research Database (Denmark)

    Chemia, Zurab; Artemieva, Irina; Thybo, Hans

    2014-01-01

    Since the discovery of diamonds in kimberlite-type rocks more than a century ago, a number of theories regarding the processes involved in kimberlite emplacement have been put forward to explain the unique properties of kimberlite magmatism. Geological data suggests that pre-existing lithosphere ...... broad limits and are, apparently controlled, by the past structure of the lithosphere and a "vigor" of lithosphere-mantle interaction, which caused kimberlite emplacements....

  14. Distributional pattern of benthic foraminiferal morpho-groups in the shelf region off Mangalore: Environmental implications

    Digital Repository Service at National Institute of Oceanography (India)

    Khare, N.; Sinha, R.; Rai, A.K.; Nigam, R.

    , the population was further placed into two broad morpho-groups namely, angular-asymmetrical and rounded-symmetrical. The surficial distribution of these groups revealed that angular-asymmetrical forms are abundant in relatively deeper region whereas rounded...

  15. Intense Collaboration In Globally Distributed Teams: Evolving Patterns Of Dependencies And Coordination

    NARCIS (Netherlands)

    K. Kumar (Kuldeep); P.C. van Fenema (Paul); M.A. von Glinow

    2004-01-01

    textabstractAs multi-national firms and major offshore outsourcing companies develop experience with global work, their globally distributed teams face the challenge of collaborating intensely without the common interaction advantages associated with collocated work. This chapter analyzes the

  16. Distribution patterns of arbuscular mycorrhizal and non-mycorrhizal plant species in Germany

    Czech Academy of Sciences Publication Activity Database

    Menzel, A.; Hempel, S.; Manceur, A. M.; Götzenberger, Lars; Moora, M.; Rilling, M.C.; Zobel, M.; Kühn, I.

    2016-01-01

    Roč. 21, August 2016 (2016), s. 78-88 ISSN 1433-8319 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhiza * distribution model * Central Europe Subject RIV: EH - Ecology , Behaviour Impact factor: 3.123, year: 2016

  17. What can flux tracking teach us about water age distribution patterns and their temporal dynamics?

    NARCIS (Netherlands)

    Hrachowitz, M.; Savenije, H.; Bogaard, T.A.; Tetzlaff, D.; Soulsby, C.

    2013-01-01

    The complex interactions of runoff generation processes underlying the hydrological response of streams remain not entirely understood at the catchment scale. Extensive research has demonstrated the utility of tracers for both inferring flow path distributions and constraining model

  18. The Identity Mapping Project: Demographic differences in patterns of distributed identity.

    Science.gov (United States)

    Gilbert, Richard L; Dionisio, John David N; Forney, Andrew; Dorin, Philip

    2015-01-01

    The advent of cloud computing and a multi-platform digital environment is giving rise to a new phase of human identity called "The Distributed Self." In this conception, aspects of the self are distributed into a variety of 2D and 3D digital personas with the capacity to reflect any number of combinations of now malleable personality traits. In this way, the source of human identity remains internal and embodied, but the expression or enactment of the self becomes increasingly external, disembodied, and distributed on demand. The Identity Mapping Project (IMP) is an interdisciplinary collaboration between psychology and computer Science designed to empirically investigate the development of distributed forms of identity. Methodologically, it collects a large database of "identity maps" - computerized graphical representations of how active someone is online and how their identity is expressed and distributed across 7 core digital domains: email, blogs/personal websites, social networks, online forums, online dating sites, character based digital games, and virtual worlds. The current paper reports on gender and age differences in online identity based on an initial database of distributed identity profiles.

  19. Changes in wind pattern alter albatross distribution and life-history traits.

    Science.gov (United States)

    Weimerskirch, Henri; Louzao, Maite; de Grissac, Sophie; Delord, Karine

    2012-01-13

    Westerly winds in the Southern Ocean have increased in intensity and moved poleward. Using long-term demographic and foraging records, we show that foraging range in wandering albatrosses has shifted poleward in conjunction with these changes in wind pattern, while their rates of travel and flight speeds have increased. Consequently, the duration of foraging trips has decreased, breeding success has improved, and birds have increased in mass by more than 1 kilogram. These positive consequences of climate change may be temporary if patterns of wind in the southern westerlies follow predicted climate change scenarios. This study stresses the importance of foraging performance as the key link between environmental changes and population processes.

  20. Disjunct distributions of freshwater snails testify to a central role of the Congo system in shaping biogeographical patterns in Africa.

    Science.gov (United States)

    Schultheiß, Roland; Van Bocxlaer, Bert; Riedel, Frank; von Rintelen, Thomas; Albrecht, Christian

    2014-03-06

    The formation of the East African Rift System has decisively influenced the distribution and evolution of tropical Africa's biota by altering climate conditions, by creating basins for large long-lived lakes, and by affecting the catchment and drainage directions of river systems. However, it remains unclear how rifting affected the biogeographical patterns of freshwater biota through time on a continental scale, which is further complicated by the scarcity of molecular data from the largest African river system, the Congo. We study these biogeographical patterns using a fossil-calibrated multi-locus phylogeny of the gastropod family Viviparidae. This group allows reconstructing drainage patterns exceptionally well because it disperses very poorly in the absence of existing freshwater connections. Our phylogeny covers localities from major drainage basins of tropical Africa and reveals highly disjunct sister-group relationships between (a) the endemic viviparids of Lake Malawi and populations from the Middle Congo as well as between (b) the Victoria region and the Okavango/Upper Zambezi area. The current study testifies to repeated disruptions of the distribution of the Viviparidae during the formation of the East African Rift System, and to a central role of the Congo River system for the distribution of the continent's freshwater fauna during the late Cenozoic. By integrating our results with previous findings on palaeohydrographical connections, we provide a spatially and temporarily explicit model of historical freshwater biogeography in tropical Africa. Finally, we review similarities and differences in patterns of vertebrate and invertebrate dispersal. Amongst others we argue that the closest relatives of present day viviparids in Lake Malawi are living in the Middle Congo River, thus shedding new light on the origin of the endemic fauna of this rift lake.

  1. Effect of land use patterns on stability and distributions of organic ...

    African Journals Online (AJOL)

    Soil aggregation is important for the resistance of land surfaces to erosion, and it influences the ability of soils to remain productive. At the same time, it is also an important process of carbon sequestration. The objectives of this study were to elucidate the effects of different land use patterns on soil aggregate stability and the ...

  2. Frequency Distribution in Domestic Microwave Ovens and Its Influence on Heating Pattern.

    Science.gov (United States)

    Luan, Donglei; Wang, Yifen; Tang, Juming; Jain, Deepali

    2017-02-01

    In this study, snapshots of operating frequency profiles of domestic microwave ovens were collected to reveal the extent of microwave frequency variations under different operation conditions. A computer simulation model was developed based on the finite difference time domain method to analyze the influence of the shifting frequency on heating patterns of foods in a microwave oven. The results showed that the operating frequencies of empty and loaded domestic microwave ovens varied widely even among ovens of the same model purchased on the same date. Each microwave oven had its unique characteristic operating frequencies, which were also affected by the location and shape of the load. The simulated heating patterns of a gellan gel model food when heated on a rotary plate agreed well with the experimental results, which supported the reliability of the developed simulation model. Simulation indicated that the heating patterns of a stationary model food load changed with the varying operating frequency. However, the heating pattern of a rotary model food load was not sensitive to microwave frequencies due to the severe edge heating overshadowing the effects of the frequency variations. © 2016 Institute of Food Technologists®.

  3. Coccolith distribution patterns in South Atlantic and Southern Ocean surface sediments in relation to environmental gradients

    DEFF Research Database (Denmark)

    Boeckel, B.; Baumann, K.-H.; Henrich, R.

    2006-01-01

    In this study, the coccolith compositions of 213 surface sediment samples from the South Atlantic and Southern Ocean were analysed with respect to the environmental parameters of the overlying surface waters. From this data set, the abundance patterns of the main species and their ecological affi...

  4. Spatial and seasonal distribution patterns of the ragged-tooth shark ...

    African Journals Online (AJOL)

    Catches from competitive shore-anglers, inshore boatbased anglers and sightings by spearfishers and divers were used to infer the spatial and seasonal movement patterns of young-of-the-year (2.4m TL) ragged-tooth sharks Carcharias taurus along ...

  5. (TG/CAn repeats in human gene families: abundance and selective patterns of distribution according to function and gene length

    Directory of Open Access Journals (Sweden)

    Ramachandran Srinivasan

    2005-06-01

    Full Text Available Abstract Background Creation of human gene families was facilitated significantly by gene duplication and diversification. The (TG/CAn repeats exhibit length variability, display genome-wide distribution, and are abundant in the human genome. Accumulation of evidences for their multiple functional roles including regulation of transcription and stimulation of recombination and splicing elect them as functional elements. Here, we report analysis of the distribution of (TG/CAn repeats in human gene families. Results The 1,317 human gene families were classified into six functional classes. Distribution of (TG/CAn repeats were analyzed both from a global perspective and from a stratified perspective based on their biological properties. The number of genes with repeats decreased with increasing repeat length and several genes (53% had repeats of multiple types in various combinations. Repeats were positively associated with the class of Signaling and communication whereas, they were negatively associated with the classes of Immune and related functions and of Information. The proportion of genes with (TG/CAn repeats in each class was proportional to the corresponding average gene length. The repeat distribution pattern in large gene families generally mirrored the global distribution pattern but differed particularly for Collagen gene family, which was rich in repeats. The position and flanking sequences of the repeats of Collagen genes showed high conservation in the Chimpanzee genome. However the majority of these repeats displayed length polymorphism. Conclusion Positive association of repeats with genes of Signaling and communication points to their role in modulation of transcription. Negative association of repeats in genes of Information relates to the smaller gene length, higher expression and fundamental role in cellular physiology. In genes of Immune and related functions negative association of repeats perhaps relates to the smaller gene

  6. Geographic location, network patterns and population distribution of rural settlements in Greece

    Science.gov (United States)

    Asimakopoulos, Avraam; Mogios, Emmanuel; Xenikos, Dimitrios G.

    2016-10-01

    Our work addresses the problem of how social networks are embedded in space, by studying the spread of human population over complex geomorphological terrain. We focus on villages or small cities up to a few thousand inhabitants located in mountainous areas in Greece. This terrain presents a familiar tree-like structure of valleys and land plateaus. Cities are found more often at lower altitudes and exhibit preference on south orientation. Furthermore, the population generally avoids flat land plateaus and river beds, preferring locations slightly uphill, away from the plateau edge. Despite the location diversity regarding geomorphological parameters, we find certain quantitative norms when we examine location and population distributions relative to the (man-made) transportation network. In particular, settlements at radial distance ℓ away from road network junctions have the same mean altitude, practically independent of ℓ ranging from a few meters to 10 km. Similarly, the distribution of the settlement population at any given ℓ is the same for all ℓ. Finally, the cumulative distribution of the number of rural cities n(ℓ) is fitted to the Weibull distribution, suggesting that human decisions for creating settlements could be paralleled to mechanisms typically attributed to this particular statistical distribution.

  7. Distribution pattern of anthroponotic cutaneous leishmaniasis caused by Leishmania tropica in Western Afghanistan during 2013-2014.

    Science.gov (United States)

    Fakhar, Mahdi; Karamian, Mehdi; Ghatee, Mohammad Amin; Taylor, Walter Robert; Pazoki Ghohe, Hossein; Rasooli, Sayed Abobakar

    2017-12-01

    Anthroponotic cutaneous leishmaniasis (ACL), caused by Leishmania tropica, is the main cause of cutaneous leishmaniasis (CL) in the Herat province, Western Afghanistan. We investigated the role of environmental factors on ACL distribution in Herat. Epidemiological data from 2457 patients were retrieved from the local WHO sub-office. Shapefile layers of districts, cities, villages, land cover, soil type and digital elevation model (DEM) of the Herat province were used to assess, by logistic regression modelling, the effects of land cover, soil types, elevation, and proximity to the Harirud river on the distribution of ACL. The key determinants of distribution were: (i) close proximity to the Harirud river, (ii) elevation between 700 and 1200m, (iii) intensive and intermittent irrigated cultivated land, and (iv) Haplocalcids with Torriorthents and Torrifluvents soil types. No ACL cases were found below 700m, and a few cases were present at >1200m in irrigated areas around the Harirud river. These findings suggest that moist soil and the humidity from irrigated areas found between 700 and 1200m provide suitable breeding sites of Phlebotomus sergenti, the main sandfly vector of L. tropica in Afghanistan. The effect of elevation also explains the predominance of ACL over ZCL in this region. The present study showed that distribution of ACL is strongly associated with environmental factors in West Afghanistan where the political and socio-economic conditions may also affect the epidemiology of CL. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Distribution patterns of elements in dental enamel of G. blacki: a preliminary dietary investigation using SRXRF

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Yating; Hu, Yaowu; Shang, Xue; Wang, Changsui [Chinese Academy of Sciences, Lab of Human Evolution, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing (China); University of Chinese Academy of Sciences, Department of Scientific History and Archaeometry, School of Humanities, Beijing (China); Jin, Changzhu; Zhang, Yingqi [Chinese Academy of Sciences, Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing (China)

    2013-04-15

    We measured the elemental mappings in dental enamel of Gigantopithecus blacki (n=3) using synchrotron radiation X-ray fluorescence (SRXRF) to understand the dietary variation during the time of tooth eruption. In order to account for the effects of diagenesis on the variation of elements in these fossil teeth, we compared the Fe and Mn elemental distribution and levels in dental enamel of G. blacki with that of a single modern pig tooth and found no differences. The observation of the variations of Sr, Ca and RE (rare earth elements) distribution in the incremental lines reveals that the plant foods utilized by G. blacki from the early Pleistocene or the middle Pleistocene had varied during the formation of dental enamel, possibly caused by the change of living environment or food resources. The variations of elemental distribution in different incremental lines are very promising to understand the nutritional and physical stress of G. blacki during the tooth eruption and environmental adaptations. (orig.)

  9. Patterns of Failure After Proton Therapy in Medulloblastoma; Linear Energy Transfer Distributions and Relative Biological Effectiveness Associations for Relapses

    Energy Technology Data Exchange (ETDEWEB)

    Sethi, Roshan V. [Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Giantsoudi, Drosoula; Raiford, Michael; Malhi, Imran; Niemierko, Andrzej [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Rapalino, Otto; Caruso, Paul [Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts (United States); Yock, Torunn I.; Tarbell, Nancy J.; Paganetti, Harald [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); MacDonald, Shannon M., E-mail: smacdonald@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-03-01

    Purpose: The pattern of failure in medulloblastoma patients treated with proton radiation therapy is unknown. For this increasingly used modality, it is important to ensure that outcomes are comparable to those in modern photon series. It has been suggested this pattern may differ from photons because of variations in linear energy transfer (LET) and relative biological effectiveness (RBE). In addition, the use of matching fields for delivery of craniospinal irradiation (CSI) may influence patterns of relapse. Here we report the patterns of failure after the use of protons, compare it to that in the available photon literature, and determine the LET and RBE values in areas of recurrence. Methods and Materials: Retrospective review of patients with medulloblastoma treated with proton radiation therapy at Massachusetts General Hospital (MGH) between 2002 and 2011. We documented the locations of first relapse. Discrete failures were contoured on the original planning computed tomography scan. Monte Carlo calculation methods were used to estimate the proton LET distribution. Models were used to estimate RBE values based on the LET distributions. Results: A total of 109 patients were followed for a median of 38.8 months (range, 1.4-119.2 months). Of the patients, 16 experienced relapse. Relapse involved the supratentorial compartment (n=8), spinal compartment (n=11), and posterior fossa (n=5). Eleven failures were isolated to a single compartment; 6 failures in the spine, 4 failures in the supratentorium, and 1 failure in the posterior fossa. The remaining patients had multiple sites of disease. One isolated spinal failure occurred at the spinal junction of 2 fields. None of the 70 patients treated with an involved-field-only boost failed in the posterior fossa outside of the tumor bed. We found no correlation between Monte Carlo-calculated LET distribution and regions of recurrence. Conclusions: The most common site of failure in patients treated with protons for

  10. Analysis of Road Network Pattern Considering Population Distribution and Central Business District.

    Directory of Open Access Journals (Sweden)

    Fangxia Zhao

    Full Text Available This paper proposes a road network growing model with the consideration of population distribution and central business district (CBD attraction. In the model, the relative neighborhood graph (RNG is introduced as the connection mechanism to capture the characteristics of road network topology. The simulation experiment is set up to illustrate the effects of population distribution and CBD attraction on the characteristics of road network. Moreover, several topological attributes of road network is evaluated by using coverage, circuitness, treeness and total length in the experiment. Finally, the suggested model is verified in the simulation of China and Beijing Highway networks.

  11. Patterns in the spatial distribution of Peruvian anchovy ( Engraulis ringens) revealed by spatially explicit fishing data

    Science.gov (United States)

    Bertrand, Sophie; Díaz, Erich; Lengaigne, Matthieu

    2008-10-01

    Peruvian anchovy ( Engraulis ringens) stock abundance is tightly driven by the high and unpredictable variability of the Humboldt Current Ecosystem. Management of the fishery therefore cannot rely on mid- or long-term management policy alone but needs to be adaptive at relatively short time scales. Regular acoustic surveys are performed on the stock at intervals of 2 to 4 times a year, but there is a need for more time continuous monitoring indicators to ensure that management can respond at suitable time scales. Existing literature suggests that spatially explicit data on the location of fishing activities could be used as a proxy for target stock distribution. Spatially explicit commercial fishing data could therefore guide adaptive management decisions at shorter time scales than is possible through scientific stock surveys. In this study we therefore aim to (1) estimate the position of fishing operations for the entire fleet of Peruvian anchovy purse-seiners using the Peruvian satellite vessel monitoring system (VMS), and (2) quantify the extent to which the distribution of purse-seine sets describes anchovy distribution. To estimate fishing set positions from vessel tracks derived from VMS data we developed a methodology based on artificial neural networks (ANN) trained on a sample of fishing trips with known fishing set positions (exact fishing positions are known for approximately 1.5% of the fleet from an at-sea observer program). The ANN correctly identified 83% of the real fishing sets and largely outperformed comparative linear models. This network is then used to forecast fishing operations for those trips where no observers were onboard. To quantify the extent to which fishing set distribution was correlated to stock distribution we compared three metrics describing features of the distributions (the mean distance to the coast, the total area of distribution, and a clustering index) for concomitant acoustic survey observations and fishing set positions

  12. Analysis of Road Network Pattern Considering Population Distribution and Central Business District.

    Science.gov (United States)

    Zhao, Fangxia; Sun, Huijun; Wu, Jianjun; Gao, Ziyou; Liu, Ronghui

    2016-01-01

    This paper proposes a road network growing model with the consideration of population distribution and central business district (CBD) attraction. In the model, the relative neighborhood graph (RNG) is introduced as the connection mechanism to capture the characteristics of road network topology. The simulation experiment is set up to illustrate the effects of population distribution and CBD attraction on the characteristics of road network. Moreover, several topological attributes of road network is evaluated by using coverage, circuitness, treeness and total length in the experiment. Finally, the suggested model is verified in the simulation of China and Beijing Highway networks.

  13. Environmental, land cover and land use constraints on the distributional patterns of anurans: Leptodacylus species (Anura, Leptodactylidae from Dry Chaco

    Directory of Open Access Journals (Sweden)

    Regina Gabriela Medina

    2016-11-01

    Full Text Available Subtropical dry forests are among the most vulnerable biomes to land transformation at a global scale. Among them, the Dry Chaco suffers an accelerated change due to agriculture expansion and intensification. The Dry Chaco ecoregion is characterized by high levels of endemisms and species diversity, which are the result of a variety of climates and reliefs, allowing a wide variety of environments. The amphibian group exhibits a high richness in the Dry Chaco, which has been barely studied in relation to land cover changes. We used ecological niche models (ENMs to assess the potential geographic distribution of 10 Leptodactylus species (Anura, Leptodactylidae, which are mainly distributed within the Dry Chaco. We characterized these distributions environmentally, analyzed their overlap with land cover classes, and assessed their diversity of ecoregions. Also, we evaluated how these species potential distribution is affected by the transformation of land, and quantified the proportional area of the potential distribution in protected areas. We found that temperature seasonality is the main constraint to the occurrence of the species studied, whose main habitats are savannas, grasslands and croplands. The main threats to these species are the effects of climate change over spatial patterns of seasonality, which could affect their breeding and reproduction mode; the loss of their natural habitat; the exposure to contaminants used by intensive agriculture and their underrepresentation in protected areas.

  14. Patterns of spatial and temporal distribution of humpback whales at the southern limit of the Southeast Pacific breeding area.

    Science.gov (United States)

    Guidino, Chiara; Llapapasca, Miguel A; Silva, Sebastian; Alcorta, Belen; Pacheco, Aldo S

    2014-01-01

    Understanding the patterns of spatial and temporal distribution in threshold habitats of highly migratory and endangered species is important for understanding their habitat requirements and recovery trends. Herein, we present new data about the distribution of humpback whales (Megaptera novaeangliae) in neritic waters off the northern coast of Peru: an area that constitutes a transitional path from cold, upwelling waters to warm equatorial waters where the breeding habitat is located. Data was collected during four consecutive austral winter/spring seasons from 2010 to 2013, using whale-watching boats as platforms for research. A total of 1048 whales distributed between 487 groups were sighted. The spatial distribution of humpbacks resembled the characteristic segregation of whale groups according to their size/age class and social context in breeding habitats; mother and calf pairs were present in very shallow waters close to the coast, while dyads, trios or more whales were widely distributed from shallow to moderate depths over the continental shelf break. Sea surface temperatures (range: 18.2-25.9°C) in coastal waters were slightly colder than those closer to the oceanic realm, likely due to the influence of cold upwelled waters from the Humboldt Current system. Our results provide new evidence of the southward extension of the breeding region of humpback whales in the Southeast Pacific. Integrating this information with the knowledge from the rest of the breeding region and foraging grounds would enhance our current understanding of population dynamics and recovery trends of this species.

  15. Patterns of spatial and temporal distribution of humpback whales at the southern limit of the Southeast Pacific breeding area.

    Directory of Open Access Journals (Sweden)

    Chiara Guidino

    Full Text Available Understanding the patterns of spatial and temporal distribution in threshold habitats of highly migratory and endangered species is important for understanding their habitat requirements and recovery trends. Herein, we present new data about the distribution of humpback whales (Megaptera novaeangliae in neritic waters off the northern coast of Peru: an area that constitutes a transitional path from cold, upwelling waters to warm equatorial waters where the breeding habitat is located. Data was collected during four consecutive austral winter/spring seasons from 2010 to 2013, using whale-watching boats as platforms for research. A total of 1048 whales distributed between 487 groups were sighted. The spatial distribution of humpbacks resembled the characteristic segregation of whale groups according to their size/age class and social context in breeding habitats; mother and calf pairs were present in very shallow waters close to the coast, while dyads, trios or more whales were widely distributed from shallow to moderate depths over the continental shelf break. Sea surface temperatures (range: 18.2-25.9°C in coastal waters were slightly colder than those closer to the oceanic realm, likely due to the influence of cold upwelled waters from the Humboldt Current system. Our results provide new evidence of the southward extension of the breeding region of humpback whales in the Southeast Pacific. Integrating this information with the knowledge from the rest of the breeding region and foraging grounds would enhance our current understanding of population dynamics and recovery trends of this species.

  16. A study of distribution, sex differences and stability of lip print patterns in an Indian population

    Directory of Open Access Journals (Sweden)

    Neeti Kapoor

    2017-09-01

    Type I (30.63% was found to be most predominant overall in the Marathi population. Type I (29.75% and Type III (35.75% were found most prevalent in males and females respectively. Applying the Chi-Square test, statistically significant differences (p < 0.05 were observed between male and female lip print patterns in each of the quadrants individually and all quadrants taken together. The lip print patterns remained stable over a period of six-months. Being stable and with significant sex differences, lip prints can be effectively used as an important tool in forensic investigations for individualization as well as identification of sex of the donor, thus, narrowing down the scope of investigation to almost half.

  17. [Spatiotemporal distribution of air temperature and precipitation in rice growth period in Fujian Province of East China and the effects of this distribution on rice planting pattern].

    Science.gov (United States)

    Jiang, Min; Jin, Zhi-Qing; Yang, Hui; Shi, Chun-Lin; Zhu, Chao-Zhi; Lin, Wen-Xiong

    2012-12-01

    In order to investigate the effects of climate change on the rice production and rice planting pattern in Fujian Province, an analysis was made on the spatiotemporal distribution of air temperature and precipitation in rice growth period in the Province, and the possible changes of the local rice planting pattern in the future, based on the A2, B2, and A1 B scenarios of IPCC Special Report on Emission Scenario (SRES). In the future, the rice growth period's air temperature in the Province tended to be increased, and the increment would be increased with time, with the maximum for single cropping rice and being 0.3-2.4 degrees C and 1.5-3.4 degrees C in 2011-2030 and 2031 -2050, respectively. For early rice and late rice, the increment of their growth period's air temperature would be 0.2-0.9 degrees C and 0.7-1.7 degrees C in 2011-2030 and 0.3-2.1 degrees C and 0.5-3.6 degrees C in 2031-2050, respectively, but the annual fluctuation of the mean daily temperature would be most obvious for late rice. The rice growth period's precipitation in most parts of the Province also tended to be increased, and the increment for early rice, single cropping rice, and late rice would be 10%-40%, 10%-30%, and 10%-20%, respectively. The annual fluctuation of the precipitation would be most obvious for the early rice in southeastern Fujian. The elevated air temperature in the future could induce the increase of > or = 10 degrees C accumulated temperature, and lengthen the rice growth season, making it possible to replace early and medium-maturity varieties with late-maturity varieties, and to adopt double-rice planting pattern instead of single-rice planting pattern.

  18. Distribution patterns, dermatomal anesthesia, and Ropivacaine serum concentrations after bilateral dualtransversus abdominis plane block

    DEFF Research Database (Denmark)

    Johansen, Sys Stybe

    2012-01-01

    The ability of transversus abdominis plane (TAP) blocks to anesthetize the upper abdomen remains debatable. We aimed to describe the local anesthetic distribution following ultrasound-guided TAP blocks with repeated magnetic resonance imaging investigations and to relate this to the resulting...

  19. Distribution patterns, stock size and life-history strategies of cape ...

    African Journals Online (AJOL)

    Research surveys of Cape horse mackerel Trachurus trachurus capensis abundance on the south coast of South Africa are complicated because changes in the species' vertical and horizontal distribution limit the value of stock assessments based a single survey method. Annual bottom trawl surveys conducted in spring ...

  20. Potential impacts of climate change on the distributions and diversity patterns of European mammals

    DEFF Research Database (Denmark)

    Lewinsky, Irina; Skov, Flemming; Svenning, J.-C.

    2007-01-01

    The Intergovernmental Panel on Climate Change (IPCC) predicts an increase in global temperatures of between 1.4°C and 5.8°C during the 21st century, as a result of elevated CO2 levels. Using bioclimatic envelope models, we evaluate the potential impact of climate change on the distributions and s...

  1. Dietary protein intake and distribution patterns of well-trained Dutch athletes

    NARCIS (Netherlands)

    Gillen, Jenna B.; Trommelen, Jorn; Wardenaar, Floris C.; Brinkmans, Naomi Y.J.; Versteegen, Joline J.; Jonvik, Kristin L.; Kapp, Christoph; Vries, de Jeanne; Borne, van den Joost J.G.C.; Gibala, Martin J.; Loon, van Luc J.C.

    2017-01-01

    Dietary protein intake should be optimized in all athletes to ensure proper recovery and enhance the skeletal muscle adaptive response to exercise training. In addition to total protein intake, the use of specific proteincontaining food sources and the distribution of protein throughout the day

  2. Influence of Off-Take Angles on Flow Distribution Pattern at Concave ...

    African Journals Online (AJOL)

    ... investigate the effect of off-take angles on the flow distribution at a concave channel bifurcation. Seven different off-take angles with varied main channel flow rates were used for the study. Predicting equations for the off-take discharge dependent on the off-take angles, main channel discharges, dispersion coefficients and ...

  3. Benthic Crustacea and Mollusca distribution in Arctic fjord – case study of patterns in Hornsund, Svalbard

    Directory of Open Access Journals (Sweden)

    Anna Drewnik

    2017-10-01

    Full Text Available We present the results of species distribution modeling conducted on macrobenthic occurrence data collected between 2002 and 2014 in Arctic fjord – Hornsund. We focus on species from Mollusca and Crustacea taxa. This study investigates the importance of individual environmental factors for benthic species distribution, with a special emphasis on bottom water temperature. It aims to verify the hypothesis that the distribution of species is controlled by low water temperatures in the fjord and that the inner basins of the fjord serve as potential refugia for Arctic species threatened by the climate change-related intensification of warmer water inflows. Our results confirm the importance of bottom water temperature in regulating the presence of benthic fauna in the Hornsund fjord. The distribution of studied species is clearly related to specific water mass – colder (1°C; and the preferred temperature regimes seem to be species specific and unrelated to analyzed groups. This study supports the notion that inner basins of the Hornsund fjord are potential refugia for cold water Arctic fauna, while the outer and central basins provide suitable habitats for fauna that prefer warmer waters.

  4. MVC Design Pattern for the multi framework distributed applications using XML, spring and struts framework

    OpenAIRE

    Praveen Gupta,; Prof. M.C. Govil

    2010-01-01

    The model view controller (MVC) is a fundamental design pattern for the separation between user interface logic and business logic. Since applications are very large in size these days and the MVC designpattern can weak the coupling among the different application tiers of application. this paper presents a web application framework based on MVC in J2EE platform, and extends it with XML so that the framework is more flexible, expansible and easy to maintain. This is a multi tier system includ...

  5. Depth distribution of preferential flow patterns in a sandy loam soil as affected by tillage

    Directory of Open Access Journals (Sweden)

    C. T. Petersen

    1997-01-01

    Full Text Available Dye-tracer studies using the anionic dye Brilliant Blue FCF were conducted on a structured sandy loam soil (Typic Agrudalf. 25 mm of dye solution was applied to the surface of 11 1.6 x 1.6 m field plots, some of which had been subjected to conventional seed bed preparation (harrowing while others had been rotovated to either 5 or 15 cm depth before sowing. The soil was excavated to about 160 cm depth one or two days after dye application. Flow patterns and structural features appearing on vertical or horizontal cross sections were examined and photographed. The flow patterns were digitized, and depth functions for the number of activated flow pathways and the degree of dye coverage were calculated. Dye was found below 100 cm depth on 26 out of 33 vertical cross sections made in conventionally tilled plots showing that preferential flow was a prevailing phenomenon. The depth-averaged number of stained flow pathways in the 25-100 cm layer was significantly smaller in a plot rotovated to 5 cm depth than in a conventionally tilled plot, both under relatively dry initial soil conditions and when the entire soil profiles were initially at field capacity. There were no examples of dye penetration below 25 cm depth one month after deep rotovation. Distinct horizontal structures in flow patterns appearing at 20-40 cm depth coupled with changes in flow domains indicated soil layering with abrupt changes in soil structure and hydraulic properties.

  6. Habitual sleep patterns and the distribution of body mass index: cross-sectional findings among Swedish men and women.

    Science.gov (United States)

    Westerlund, Anna; Bottai, Matteo; Adami, Hans-Olov; Bellocco, Rino; Nyrén, Olof; Åkerstedt, Torbjörn; Lagerros, Ylva Trolle

    2014-10-01

    To compare distributions of body mass index (BMI) between individuals with different habitual sleep patterns. We performed cross-sectional analyses of 40,197 Swedish adults (64% women), who reported sleep duration and quality, weight, height, and possible confounding factors in 1997. Using quantile regression, we estimated associations between sleep patterns and selected percentiles of the distribution of BMI. While the medians were similar, larger adjusted values of BMI were estimated in the upper part of the distribution among men and women with short sleep (≤5 h) compared with medium-length sleep (6-8 h). For example, in men, the 90th percentile of BMI was 0.80 kg/m(2) (95% confidence interval: 0.17-1.43 kg/m(2)) higher among short sleepers. In women, long sleepers (≥9 h) also showed larger values in the upper part of the BMI distribution; the 90th percentile was 1.23 kg/m(2) (0.42-2.04 kg/m(2)) higher than in medium-length sleepers. In male long sleepers, smaller values were estimated in the lower part of the BMI distribution; the 10th percentile was 0.84 kg/m(2) lower (0.35-1.32 kg/m(2)) than in medium-length sleepers. The 90th percentile of BMI in women with poor-quality compared with good-quality sleep was larger by 0.82 kg/m(2) (0.47-1.16 kg/m(2)); the 10th percentile was smaller by 0.17 kg/m(2) (0.02-0.32 kg/m(2)). Short, long or poor-quality sleepers showed larger, or smaller, values at the tails of the BMI distribution, but similar medians. Hence, unfavorable sleep patterns and BMI were associated only in a subset of this study population. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Probabilistic approach to pattern selection

    Science.gov (United States)

    Yukalov, V. I.

    2001-03-01

    The problem of pattern selection arises when the evolution equations have many solutions, whereas observed patterns constitute a much more restricted set. An approach is advanced for treating the problem of pattern selection by defining the probability distribution of patterns. Then the most probable pattern naturally corresponds to the largest probability weight. This approach provides the ordering principle for the multiplicity of solutions explaining why some of them are more preferable than others. The approach is applied to solving the problem of turbulent photon filamentation in resonant media.

  8. Diversity and distribution of genetic variation in gammarids: Comparing patterns between invasive and non-invasive species.

    Science.gov (United States)

    Baltazar-Soares, Miguel; Paiva, Filipa; Chen, Yiyong; Zhan, Aibin; Briski, Elizabeta

    2017-10-01

    Biological invasions are worldwide phenomena that have reached alarming levels among aquatic species. There are key challenges to understand the factors behind invasion propensity of non-native populations in invasion biology. Interestingly, interpretations cannot be expanded to higher taxonomic levels due to the fact that in the same genus, there are species that are notorious invaders and those that never spread outside their native range. Such variation in invasion propensity offers the possibility to explore, at fine-scale taxonomic level, the existence of specific characteristics that might predict the variability in invasion success. In this work, we explored this possibility from a molecular perspective. The objective was to provide a better understanding of the genetic diversity distribution in the native range of species that exhibit contrasting invasive propensities. For this purpose, we used a total of 784 sequences of the cytochrome c oxidase subunit I of mitochondrial DNA (mtDNA-COI) collected from seven Gammaroidea, a superfamily of Amphipoda that includes species that are both successful invaders (Gammarus tigrinus, Pontogammarus maeoticus, and Obesogammarus crassus) and strictly restricted to their native regions (Gammarus locusta, Gammarus salinus, Gammarus zaddachi, and Gammarus oceanicus). Despite that genetic diversity did not differ between invasive and non-invasive species, we observed that populations of non-invasive species showed a higher degree of genetic differentiation. Furthermore, we found that both geographic and evolutionary distances might explain genetic differentiation in both non-native and native ranges. This suggests that the lack of population genetic structure may facilitate the distribution of mutations that despite arising in the native range may be beneficial in invasive ranges. The fact that evolutionary distances explained genetic differentiation more often than geographic distances points toward that deep lineage

  9. Nucleic acid distribution pattern in avian erythrocytes and mammalian lymphocytes: comparative studies by fluorescence microscopy and digital imaging analytical techniques.

    Science.gov (United States)

    Isitor, G N; Asgarali, Z; Pouching, K

    2008-12-01

    Nucleated erythrocytes of healthy domestic chicken and ducks, and lymphocytes of healthy Sprague Dawley rats were evaluated for nucleic acid distribution pattern, employing light and fluorescence microscopy procedures, as well as digital imaging analytical methods. The results demonstrate a unique organization of nuclear DNA of mature chicken and duck erythrocytes, as well as immature duck erythrocytes, as delineated spherical nuclear bodies that mostly corresponded with euchromatin zones of the cells in routine Wright-stain blood smears. The nuclear DNA of the rat lymphocytes, on the other hand, was observed as a more diffuse green fluorescing nuclear areas, with punctate variably-sized diffuse areas of RNA red fluorescence. RNA red color fluorescence was also evident in the narrow cytoplasm of the lymphocytes, especially in large lymphocytes, in comparison with the cytoplasm of the mature avian erythrocytes that completely lacked any nucleic acid fluorescence. Nuclear RNA fluorescence was lacking in the mature chicken erythrocytes, compared with those of the mature and immature duck erythrocytes as well as lymphocytes of both avian and rats blood. The significance of these findings lies in the establishment of normal benchmarks for the nuclear and cytoplasmic nucleic acid pattern in eukaryotic cells. These normal benchmarks become valuable in rapid diagnostic situations associated with pathologies, such as the presence of viral nuclear and cytoplasmic inclusion bodies that can alter the nucleic acid pattern of the host cells, and in conditions of cellular abnormal protein aggregations. Variability of cellular nucleic acid pattern can also aid in prognostic assessments of neoplastic conditions.

  10. Spatial distribution patterns of terrestrial bird assemblages on islands of the Sabana–Camagüey Archipelago, Cuba: evaluating nestedness and co–occurrence patterns

    Directory of Open Access Journals (Sweden)

    Mancina, C. A.

    2013-12-01

    Full Text Available Using distribution data of 131 terrestrial bird species on 17 islands of the Archipelago Sabana–Camagüey, Cuba, we tested for non–randomness in presence–absence matrices with respect to co–occurrence and nestedness. We conducted separate analyses for the whole assemblage and sub–matrices according to trophic levels and residence status (breeding and migratory. We also explored the influence of weighting factors such as island area and isolation. The C–occurrence analyses were susceptible to the species subsets and the weighting factors. Unweighted analyses revealed a significant negative co–occurrence pattern for the entire assemblage and for most sub–matrices. The area weighted analyses always indicated strong non–random structure. However, an analysis with intra–guild species pairs showed that most pairs were randomly assembled; very few pairs had a significant segregated pattern. Bird assemblages followed a nested subset structure across islands. Nestedness was strongly correlated with area and unrelated with island isolation. Overall, this study suggests that terrestrial bird assemblages were shaped by extinction processes mediated through area effects rather than interspecific trophic guild competition. Data suggest that conservation of largest islands will guarantee high terrestrial bird richness on the archipelago.

  11. Computation of antenna pattern correlation and MIMO performance by means of surface current distribution and spherical wave theory

    Directory of Open Access Journals (Sweden)

    O. Klemp

    2006-01-01

    Full Text Available In order to satisfy the stringent demand for an accurate prediction of MIMO channel capacity and diversity performance in wireless communications, more effective and suitable models that account for real antenna radiation behavior have to be taken into account. One of the main challenges is the accurate modeling of antenna correlation that is directly related to the amount of channel capacity or diversity gain which might be achieved in multi element antenna configurations. Therefore spherical wave theory in electromagnetics is a well known technique to express antenna far fields by means of a compact field expansion with a reduced number of unknowns that was recently applied to derive an analytical approach in the computation of antenna pattern correlation. In this paper we present a novel and efficient computational technique to determine antenna pattern correlation based on the evaluation of the surface current distribution by means of a spherical mode expansion.

  12. Lumbar Vertebral Endplate Defects on Magnetic Resonance Images: Classification, Distribution Patterns, and Associations with Modic Changes and Disc Degeneration.

    Science.gov (United States)

    Feng, Zhiyun; Liu, Yuanhao; Yang, Ge; Battié, Michele C; Wang, Yue

    2017-10-10

    A cross-sectional MR imaging study. To classify and characterize endplate defects using routine lumbar MR images, and to determine associations of endplate defects with Modic Changes (MCs) and disc degeneration. Previously, a cadaveric study revealed that endplate lesions were common and associated with back pain history. New in vivo approaches appropriate for clinical studies are needed to further this potentially important line of research on the clinical significance of endplate lesions, including their relation with MCs, disc degeneration and back pain. Using a MRI archive, 1564 endplates of 133 subjects (59 men and 74 women, mean age 58.9 ± 11.9 years) with the presence of MCs were retrospectively collected from April of 2014 to June of 2015. Based on morphological characteristics, a protocol was proposed to identify three distinct types of endplate defects, including focal, corner and erosive defects. The location, size and distribution patterns of various endplate lesions were characterized. MCs and disc degeneration were measured to examine their associations with endplate defects. Endplate defects were observed in 27.8% of endplates studied. Greater age was associated with the presence of endplate defects. Focal defects were the most common (13.5%), followed by erosive defects (11.1%) and corner defects (3.2%). Defect types also differed in size and distribution patterns. Endplate defects and MCs had similar distribution patterns in the lumbar spine. The presence and size of endplate defects were associated with the presence of MCs (OR = 4.29, P system may facilitate clinical studies on endplate defects. 4.

  13. Dietary Protein Intake and Distribution Patterns of Well-Trained Dutch Athletes.

    Science.gov (United States)

    Gillen, Jenna B; Trommelen, Jorn; Wardenaar, Floris C; Brinkmans, Naomi Y J; Versteegen, Joline J; Jonvik, Kristin L; Kapp, Christoph; de Vries, Jeanne; van den Borne, Joost J G C; Gibala, Martin J; van Loon, Luc J C

    2017-04-01

    Dietary protein intake should be optimized in all athletes to ensure proper recovery and enhance the skeletal muscle adaptive response to exercise training. In addition to total protein intake, the use of specific proteincontaining food sources and the distribution of protein throughout the day are relevant for optimizing protein intake in athletes. In the present study, we examined the daily intake and distribution of various proteincontaining food sources in a large cohort of strength, endurance and team-sport athletes. Well-trained male (n=327) and female (n=226) athletes completed multiple web-based 24-hr dietary recalls over a 2-4 wk period. Total energy intake, the contribution of animal- and plant-based proteins to daily protein intake, and protein intake at six eating moments were determined. Daily protein intake averaged 108±33 and 90±24 g in men and women, respectively, which corresponded to relative intakes of 1.5±0.4 and 1.4±0.4 g/kg. Dietary protein intake was correlated with total energy intake in strength (r=0.71, p athletes. Animal and plant-based sources of protein intake was 57% and 43%, respectively. The distribution of protein intake was 19% (19±8 g) at breakfast, 24% (25±13 g) at lunch and 38% (38±15 g) at dinner. Protein intake was below the recommended 20 g for 58% of athletes at breakfast, 36% at lunch and 8% at dinner. In summary, this survey of athletes revealed they habitually consume > 1.2 g protein/kg/d, but the distribution throughout the day may be suboptimal to maximize the skeletal muscle adaptive response to training.

  14. Density and spatial distribution of Parkia biglobosa pattern in Benin under climate change

    Directory of Open Access Journals (Sweden)

    Fafunkè Titilayo Dotchamou

    2016-06-01

    Full Text Available Parkia biglobosa is an indigenous species which, traditionally contributes to the resilience of the agricultural production system in terms of food security, source of income, poverty reduction and ecosystem stability. Therefore, it is important to improve knowledge on its density, current and future spatial distribution. The main objective of this study is to evaluate the tree density, the climate change effects on the spatial distribution of the species in the future for better conservation. The modeling of the current and future geographical distribution of the species is based on the principle of Maximum Entropy (MaxEnt on a total of 286 occurrence points from field work and Global Biodiversity Information Facility GBIF-Data Portal-(www.gbif.org. Two climatic models (HadGEM2_ES and Csiro_mk3_6_0 have been used under two scenarios RCP 2.6 and RCP 8.5 for the projection of the species distribution at the horizon 2050. The correlation analyses and Jackknife test have helped to identify seven variables which are less correlated (r < 0.80 with highest modeling participation. The soil, annual precipitation (BIO12 and temperature (diurnal average Deviation are the variables which have mostly contributed to performance of the models. Currently, 53% of national territory, spread from north to south is very suitable to the cultivation of P. biglobosa. The scenarios have predicted at the horizon 2050, a loss of the habitats which are currently very suitable for the cultivation and conservation of P. biglobosa, to the benefit of moderate and weak habitats. 51% and 57% are the highest proportion of this lost which will be registered with HadGEM2_ES model under two scenarios. These results revealed that the suitable habitat of the species is threatened by climate change in Benin. In order to limit damage such as decreased productivity, extinction of species, some appropriate solutions must be found.

  15. Alien animals in South Africa – composition, introduction history, origins and distribution patterns

    OpenAIRE

    Mike D. Picker; Griffiths, Charles L.

    2017-01-01

    Background: There is no comprehensive inventory and analysis of the composition, distribution, origin and rate of introduction of the alien fauna of South Africa. Objectives: To provide such an analysis to facilitate effective ecological management, and compile a comprehensive inventory of introduced animal species across major habitats. Methods: All available databases and references were used to compile the inventory, forming the basis of subsequent analyses. A graduated map was produced to...

  16. Distribution Patterns and Phylogeny of Marine Stramenopiles in the North Pacific Ocean

    OpenAIRE

    Lin, Yun-Chi; Campbell, Tracy; Chung, Chih-Ching; Gong, Gwo-Ching; Chiang, Kuo-Ping; Worden, Alexandra Z.

    2012-01-01

    Marine stramenopiles (MASTs) are a diverse suite of eukaryotic microbes found in marine environments. Several MAST lineages are thought to contain heterotrophic nanoflagellates. However,