When invasive ants meet: effects of outbreeding on queen performance in the tramp ant Cardiocondyla itsukii.

PubMed

Heinze, Jürgen; Frohschammer, Sabine; Bernadou, Abel

2017-08-18

Most disturbed habitats in the tropics and subtropics harbor numerous species of invasive ants, and occasionally the same species has been introduced repeatedly from multiple geographical sources. We examined how experimental crossbreeding between sexuals from different populations affects the fitness of queens of the tramp ant Cardiocondyla itsukii, which is widely distributed in Asia and the Pacific Islands. Eggs laid by queens that mated with nestmate males had a higher hatching rate than eggs laid by queens mated to males from neighboring (Hawaii × Kauai) or distant introduced populations (Hawaii/Kauai × Okinawa). Furthermore, inbreeding queens had a longer lifespan and produced a less female-biased offspring sex ratio than queens from allopatric mating. This suggests that the genetic divergence between different source populations may already be so large that in case of multiple invasions eventual crossbreeding might negatively affect the fitness of tramp ants. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Inferring the origin of populations introduced from a genetically structured native range by approximate Bayesian computation: case study of the invasive ladybird Harmonia axyridis

USDA-ARS?s Scientific Manuscript database

The correct identification of the source population of an invasive species is a prerequisite for defining and testing different hypotheses concerning the environmental and evolutionary factors responsible for biological invasions. The native area of invasive species may be large, barely known and/or...

Conservation of eelgrass (Zostera marina) genetic diversity in a mesocosm-based restoration experiment.

PubMed

Ort, Brian S; Cohen, C Sarah; Boyer, Katharyn E; Reynolds, Laura K; Tam, Sheh May; Wyllie-Echeverria, Sandy

2014-01-01

Eelgrass (Zostera marina) forms the foundation of an important shallow coastal community in protected estuaries and bays. Widespread population declines have stimulated restoration efforts, but these have often overlooked the importance of maintaining the evolutionary potential of restored populations by minimizing the reduction in genetic diversity that typically accompanies restoration. In an experiment simulating a small-scale restoration, we tested the effectiveness of a buoy-deployed seeding technique to maintain genetic diversity comparable to the seed source populations. Seeds from three extant source populations in San Francisco Bay were introduced into eighteen flow-through baywater mesocosms. Following seedling establishment, we used seven polymorphic microsatellite loci to compare genetic diversity indices from 128 shoots to those found in the source populations. Importantly, allelic richness and expected heterozygosity were not significantly reduced in the mesocosms, which also preserved the strong population differentiation present among source populations. However, the inbreeding coefficient F IS was elevated in two of the three sets of mesocosms when they were grouped according to their source population. This is probably a Wahlund effect from confining all half-siblings within each spathe to a single mesocosm, elevating F IS when the mesocosms were considered together. The conservation of most alleles and preservation of expected heterozygosity suggests that this seeding technique is an improvement over whole-shoot transplantation in the conservation of genetic diversity in eelgrass restoration efforts.

Conservation of Eelgrass (Zostera marina) Genetic Diversity in a Mesocosm-Based Restoration Experiment

PubMed Central

Ort, Brian S.; Cohen, C. Sarah; Boyer, Katharyn E.; Reynolds, Laura K.; Tam, Sheh May; Wyllie-Echeverria, Sandy

2014-01-01

Eelgrass (Zostera marina) forms the foundation of an important shallow coastal community in protected estuaries and bays. Widespread population declines have stimulated restoration efforts, but these have often overlooked the importance of maintaining the evolutionary potential of restored populations by minimizing the reduction in genetic diversity that typically accompanies restoration. In an experiment simulating a small-scale restoration, we tested the effectiveness of a buoy-deployed seeding technique to maintain genetic diversity comparable to the seed source populations. Seeds from three extant source populations in San Francisco Bay were introduced into eighteen flow-through baywater mesocosms. Following seedling establishment, we used seven polymorphic microsatellite loci to compare genetic diversity indices from 128 shoots to those found in the source populations. Importantly, allelic richness and expected heterozygosity were not significantly reduced in the mesocosms, which also preserved the strong population differentiation present among source populations. However, the inbreeding coefficient F IS was elevated in two of the three sets of mesocosms when they were grouped according to their source population. This is probably a Wahlund effect from confining all half-siblings within each spathe to a single mesocosm, elevating F IS when the mesocosms were considered together. The conservation of most alleles and preservation of expected heterozygosity suggests that this seeding technique is an improvement over whole-shoot transplantation in the conservation of genetic diversity in eelgrass restoration efforts. PMID:24586683

Maintenance of Genetic Diversity in an Introduced Island Population of Guanacos after Seven Decades and Two Severe Demographic Bottlenecks: Implications for Camelid Conservation

PubMed Central

von Borries, Rainer; Johnson, Warren E.; Franklin, William L.; Marín, Juan C.

2014-01-01

Fifteen guanacos were introduced to Staats Island in the Falklands/Malvinas archipelago from Patagonia in the 1930s. Twenty five years later, the population was culled from 300 to 10–20 individuals, but quickly rebounded to a population of almost 400 animals that today retain the genetic signature of the founding event and later bottleneck. The goals of this study were to (i) make a genetic assessment of this island population through comparisons with mainland populations and simulations, and (ii) assess the likely source-population of the introduced guanacos. Genetic variation was estimated from 513 bp of mitochondrial DNA sequence and 15 microsatellite loci among 154 guanacos collected from eight localities, including the adjacent mainland and the islands of Tierra del Fuego and Staats Island. Of the 23 haplotypes observed among our samples, the Staats Island population only contained three haplotypes, all of which were shared with the coastal Monte Leon population in southern Patagonia. Mitochondrial DNA and microsatellite variations on Staats Island were comparable to most mainland populations and greater than those observed on Tierra del Fuego. Patterns of genetic structure suggest that the Staats Island guanaco population was founded with animals from southern Patagonia (as opposed to northern Patagonia or Tierra del Fuego), but that effective reductions in population size lasted only a few generations and that surviving animals were a random sample of the pre-bottleneck genetic variation. PMID:24663026

Maintenance of genetic diversity in an introduced island population of guanacos after seven decades and two severe demographic bottlenecks: implications for camelid conservation.

PubMed

González, Benito A; Orozco-Terwengel, Pablo; von Borries, Rainer; Johnson, Warren E; Franklin, William L; Marín, Juan C

2014-01-01

Fifteen guanacos were introduced to Staats Island in the Falklands/Malvinas archipelago from Patagonia in the 1930s. Twenty five years later, the population was culled from 300 to 10-20 individuals, but quickly rebounded to a population of almost 400 animals that today retain the genetic signature of the founding event and later bottleneck. The goals of this study were to (i) make a genetic assessment of this island population through comparisons with mainland populations and simulations, and (ii) assess the likely source-population of the introduced guanacos. Genetic variation was estimated from 513 bp of mitochondrial DNA sequence and 15 microsatellite loci among 154 guanacos collected from eight localities, including the adjacent mainland and the islands of Tierra del Fuego and Staats Island. Of the 23 haplotypes observed among our samples, the Staats Island population only contained three haplotypes, all of which were shared with the coastal Monte Leon population in southern Patagonia. Mitochondrial DNA and microsatellite variations on Staats Island were comparable to most mainland populations and greater than those observed on Tierra del Fuego. Patterns of genetic structure suggest that the Staats Island guanaco population was founded with animals from southern Patagonia (as opposed to northern Patagonia or Tierra del Fuego), but that effective reductions in population size lasted only a few generations and that surviving animals were a random sample of the pre-bottleneck genetic variation.

Phylogeography of Bufo marinus from its natural and introduced ranges.

PubMed Central

Slade, R W; Moritz, C

1998-01-01

The marine toad, Bufo marinus, has a broad natural distribution extending from the south-west of the USA to southern Peru and the central Amazon. It was introduced to several localities in the Caribbean and Pacific Oceans to control sugar cane pests. We sequenced 468 bp of mitochondrial DNA (mtDNA) containing the ND3 gene, and flanking tRNA genes from toads spanning the broad natural and introduced ranges. Consistent with the known history of introductions and expected effects of serial bottlenecks, mtDNA within introduced populations in Hawaii and Australia was uniform and most closely related to samples from eastern Venezuela and French Guiana. However, mtDNA nucleotide diversity in the geographic region spanning the source areas is also relative low (0.18-0.46%) and the absence of variation in the introduced populations precludes quantitative assessment of the reduction in genetic diversity. Unexpectedly, there was a large phylogeographic break (5.4% sequence divergence) within the natural range separating populations east and west of the Venezuelan Andes. We hypothesize that the two major lineages of B. marinus were isolated by the uplift of the eastern Andean cordillera which was completed approximately 2.7 Ma. Another species of the marinus group, B. paracnemis, had mtDNA paraphyletic, with marinus, being nested within the eastern lineage. Thus, at least one speciation event within the marinus group postdates the split within marinus. These findings suggest that the taxonomy of B. marinus should be re-evaluated and that the search for pathogens to control Australian populations should be conducted in populations from both lineages in the natural range. PMID:9628036

Malthus, the 18th century European explorers and the principle of population in Africa

PubMed Central

Reniers, Georges

2012-01-01

In the second edition of his Essay on the Principle of Population, Malthus included twelve chapters that offer a remarkable description of population dynamics from all corners of the world. His discussion of (sub-Saharan) Africa was almost entirely based on the travel accounts of James Bruce and Mungo Park, two late eighteenth century British explorers. In this essay, I introduce these sources and discuss the insights that Malthus did, or perhaps should have, derived from both. PMID:24259758

Costs of Extending the Noncontributory Pension Program for Elderly: The Mexican Case.

PubMed

Aguila, Emma; Mejia, Nelly; Perez-Arce, Francisco; Ramirez, Edgar; Rivera Illingworth, Alfonso

2016-01-01

Population aging coupled with high poverty rates among older persons and a lack of access to social-security benefits or traditional support systems have led governments in low and middle-income countries to introduce non-contributory pension programs for the elderly. This article reviews a non-contributory pension program introduced in Mexico in 2007 that has since expanded greatly. We use a variety of sources to estimate current and future costs of this program.

Factors in the Achievement of Below-Replacement Fertility in Chiang Mai, Thailand. Papers of the East-West Population Institute, Number 96, March 1986.

ERIC Educational Resources Information Center

Pardthaisong, Tieng

The study assesses the impact of family planning programs on the fertility of women in the Chiang Mai province of Thailand, where family planning programs were introduced early in 1963. The study documents and estimates the fertility trend of Chiang Mai's population from existing sources of data. A demographic survey, in which a random sample of…

Bridgehead Effect in the Worldwide Invasion of the Biocontrol Harlequin Ladybird

PubMed Central

Lombaert, Eric; Guillemaud, Thomas; Cornuet, Jean-Marie; Malausa, Thibaut; Facon, Benoît; Estoup, Arnaud

2010-01-01

Recent studies of the routes of worldwide introductions of alien organisms suggest that many widespread invasions could have stemmed not from the native range, but from a particularly successful invasive population, which serves as the source of colonists for remote new territories. We call here this phenomenon the invasive bridgehead effect. Evaluating the likelihood of such a scenario is heuristically challenging. We solved this problem by using approximate Bayesian computation methods to quantitatively compare complex invasion scenarios based on the analysis of population genetics (microsatellite variation) and historical (first observation dates) data. We applied this approach to the Harlequin ladybird Harmonia axyridis (HA), a coccinellid native to Asia that was repeatedly introduced as a biocontrol agent without becoming established for decades. We show that the recent burst of worldwide invasions of HA followed a bridgehead scenario, in which an invasive population in eastern North America acted as the source of the colonists that invaded the European, South American and African continents, with some admixture with a biocontrol strain in Europe. This demonstration of a mechanism of invasion via a bridgehead has important implications both for invasion theory (i.e., a single evolutionary shift in the bridgehead population versus multiple changes in case of introduced populations becoming invasive independently) and for ongoing efforts to manage invasions by alien organisms (i.e., heightened vigilance against invasive bridgeheads). PMID:20305822

Larvivorous fish for preventing malaria transmission

PubMed Central

Walshe, Deirdre P; Garner, Paul; Abdel-Hameed Adeel, Ahmed A; Pyke, Graham H; Burkot, Tom

2013-01-01

Background Adult anopheline mosquitoes transmit Plasmodium parasites that cause malaria. Some fish species eat mosquito larvae and pupae. In disease control policy documents, the World Health Organization includes biological control of malaria vectors by stocking ponds, rivers, and water collections near where people live with larvivorous fish to reduce Plasmodium parasite transmission. The Global Fund finances larvivorous fish programmes in some countries, and, with increasing efforts in eradication of malaria, policy makers may return to this option. We therefore assessed the evidence base for larvivorous fish programmes in malaria control. Objectives Our main objective was to evaluate whether introducing larvivorous fish to anopheline breeding sites impacts Plasmodium parasite transmission. Our secondary objective was to summarize studies evaluating whether introducing larvivorous fish influences the density and presence of Anopheles larvae and pupae in water sources, to understand whether fish can possibly have an effect. Search methods We attempted to identify all relevant studies regardless of language or publication status (published, unpublished, in press, or ongoing). We searched the following databases: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; CABS Abstracts; LILACS; and the metaRegister of Controlled Trials (mRCT) until 18 June 2013. We checked the reference lists of all studies identified by the above methods. We also examined references listed in review articles and previously compiled bibliographies to look for eligible studies. Selection criteria Randomized controlled trials and non-randomized controlled trials, including controlled before-and-after studies, controlled time series and controlled interrupted time series studies from malaria-endemic regions that introduced fish as a larvicide and reported on malaria in the community or the density of the adult anopheline population. In the absence of direct evidence of an effect on transmission, we carried out a secondary analysis on studies that evaluated the effect of introducing larvivorous fish on the density or presence of immature anopheline mosquitoes (larvae and pupae forms) in community water sources to determine whether this intervention has any potential in further research on control of malaria vectors. Data collection and analysis Three review authors screened abstracts and examined potentially relevant studies by using an eligibility form. Two review authors independently extracted data and assessed risk of bias of included studies. If relevant data were unclear or were not reported, we wrote to the trial authors for clarification. We presented data in tables, and we summarized studies that evaluated the effects of fish introduction on anopheline immature density or presence, or both. We used GRADE to summarize evidence quality. We also examined whether the authors of included studies reported on any possible adverse impact of larvivorous fish introduction on non-target native species. Main results We found no reliable studies that reported the effects of introducing larvivorous fish on malaria infection in nearby communities, on entomological inoculation rate, or on adult Anopheles density. For the secondary analysis, we examined the effects of introducing larvivorous fish on the density and presence of anopheline larvae and pupae in community water sources. We included 12 small studies, with follow-up from 22 days to five years. Studies were conducted in a variety of settings, including localized water bodies (such as wells, domestic water containers, fishponds, and pools; six studies), riverbed pools below dams (two studies), rice field plots (three studies), and water canals (two studies). All studies were at high risk of bias. The research was insufficient to determine whether larvivorous fish reduce the density of Anopheles larvae and pupae (nine studies, unpooled data, very low quality evidence). Some studies with high stocking levels of fish seemed to arrest the increase in immature anopheline populations, or to reduce the number of immature anopheline mosquitoes, compared with controls. However, this finding was not consistent, and in studies that showed a decrease in immature anopheline populations, the effect was not consistently sustained. Larvivorous fish may reduce the number of water sources withAnopheles larvae and pupae (five studies, unpooled data, low quality evidence). None of the included studies reported effects of larvivorous fish on local native fish populations or other species. Authors' conclusions Reliable research is insufficient to show whether introducing larvivorous fish reduces malaria transmission or the density of adult anopheline mosquito populations. In research examining the effects on immature anopheline stages of introducing fish to potential malaria vector breeding sites (localized water bodies such as wells and domestic water sources, rice field plots, and water canals) weak evidence suggests an effect on the density or presence of immature anopheline mosquitoes with high stocking levels of fish, but this finding is by no means consistent. We do not know whether this translates into health benefits, either with fish alone or with fish combined with other vector control measures. Our interpretation of the current evidence is that countries should not invest in fish stocking as a larval control measure in any malaria transmission areas outside the context of carefully controlled field studies or quasi-experimental designs. Research could also usefully examine the effects on native fish and other non-target species. PLAIN LANGUAGE SUMMARY Fish that feed on mosquito larvae for preventing malaria transmission Plasmodium parasites cause malaria and are transmitted by adult Anopheles mosquitoes. Programmes that introduce fish into water sources near where people live have been promoted. The theory is that these fish eat the Anopheles mosquito larvae and pupae, thus decreasing the adult mosquito population and reducing the number of people infected with Plasmodium parasites. In this review, we examined the research that evaluated introducing larvivorous fish to Anopheles mosquito breeding sites in areas where malaria was common, published up to 18 June 2013. We did not find any studies that looked at the effects of larvivorous fish on adult Anopheles mosquito populations or on the number of people infected with Plasmodium parasites. We included 12 studies that examined the effects of larvivorous fish on Anopheles larvae and pupae in different breeding sites, including localized water bodies (such as wells, domestic water containers, fishponds, and pools; six studies), riverbed pools below dams (two studies), rice field plots (three studies), and water canals (two studies). Research evidence is insufficient to show whether introduction of larvivorous fish reduces the number of Anopheles larvae and pupae in water sources (nine studies, unpooled data, very low quality evidence). However, larvivorous fish may reduce the number of water sources withAnopheles mosquito larvae and pupae (five studies, unpooled data, low quality evidence). None of the included studies examined the effects of introducing larvivorous fish on other native species present, but these studies were not designed to do this. Before much is invested in this intervention, better research is needed to determine the effect of introducing larvivorous fish on adult Anopheles populations and on the number of people infected with malaria. Researchers need to use robust controlled designs with an adequate number of sites. Also, researchers should explore whether introducing these fish affects native fish and other non-target species. PMID:24323308

Detecting black bear source-sink dynamics using individual-based genetic graphs.

PubMed

Draheim, Hope M; Moore, Jennifer A; Etter, Dwayne; Winterstein, Scott R; Scribner, Kim T

2016-07-27

Source-sink dynamics affects population connectivity, spatial genetic structure and population viability for many species. We introduce a novel approach that uses individual-based genetic graphs to identify source-sink areas within a continuously distributed population of black bears (Ursus americanus) in the northern lower peninsula (NLP) of Michigan, USA. Black bear harvest samples (n = 569, from 2002, 2006 and 2010) were genotyped at 12 microsatellite loci and locations were compared across years to identify areas of consistent occupancy over time. We compared graph metrics estimated for a genetic model with metrics from 10 ecological models to identify ecological factors that were associated with sources and sinks. We identified 62 source nodes, 16 of which represent important source areas (net flux > 0.7) and 79 sink nodes. Source strength was significantly correlated with bear local harvest density (a proxy for bear density) and habitat suitability. Additionally, resampling simulations showed our approach is robust to potential sampling bias from uneven sample dispersion. Findings demonstrate black bears in the NLP exhibit asymmetric gene flow, and individual-based genetic graphs can characterize source-sink dynamics in continuously distributed species in the absence of discrete habitat patches. Our findings warrant consideration of undetected source-sink dynamics and their implications on harvest management of game species. © 2016 The Author(s).

A computer simulation model of Wolbachia invasion for disease vector population modification.

PubMed

Guevara-Souza, Mauricio; Vallejo, Edgar E

2015-10-05

Wolbachia invasion has been proved to be a promising alternative for controlling vector-borne diseases, particularly Dengue fever. Creating computer models that can provide insight into how vector population modification can be achieved under different conditions would be most valuable for assessing the efficacy of control strategies for this disease. In this paper, we present a computer model that simulates the behavior of native mosquito populations after the introduction of mosquitoes infected with the Wolbachia bacteria. We studied how different factors such as fecundity, fitness cost of infection, migration rates, number of populations, population size, and number of introduced infected mosquitoes affect the spread of the Wolbachia bacteria among native mosquito populations. Two main scenarios of the island model are presented in this paper, with infected mosquitoes introduced into the largest source population and peripheral populations. Overall, the results are promising; Wolbachia infection spreads among native populations and the computer model is capable of reproducing the results obtained by mathematical models and field experiments. Computer models can be very useful for gaining insight into how Wolbachia invasion works and are a promising alternative for complementing experimental and mathematical approaches for vector-borne disease control.

Genetic population structure of the recently introduced Asian clam, Potamocorbula amurensis, in San Francisco Bay

USGS Publications Warehouse

Duda, T. F.

1994-01-01

The genetic population structure of the recently introduced Asian clam, Potamocorbula amurensis, in San Francisco Bay was described using starch gel electrophoresis at eight presumptive loci. Specimens were taken from five environmentally distinct sites located throughout the bay. The population maintains a high degree of genetic variation, with a mean heterozygosity of 0.295, a mean polymorphism of 0.75, and an average of 3.70 alleles per locus. The population is genetically homogeneous, as evidenced from genetic distance values and F-statistics. However, heterogeneity of populations was indicated from a contingency chi-square test. Significant deviations from Hardy-Weinberg equilibrium and heterozygote deficiencies were found at the Lap-1 locus for all populations and at the Lap-2 locus for a single population. High levels of variability could represent a universal characteristic of invading species, the levels of variability in the source population(s), and/or the dynamics of the introduction. Lack of differentiation between subpopulations may be due to the immaturity of the San Francisco Bay population, the “general purpose” phenotype genetic strategy of the species, high rates of gene flow in the population, and/or the selective neutrality of the loci investigated.

Multiscale Spatial Modeling of Human Exposure from Local Sources to Global Intake.

PubMed

Wannaz, Cedric; Fantke, Peter; Jolliet, Olivier

2018-01-16

Exposure studies, used in human health risk and impact assessments of chemicals, are largely performed locally or regionally. It is usually not known how global impacts resulting from exposure to point source emissions compare to local impacts. To address this problem, we introduce Pangea, an innovative multiscale, spatial multimedia fate and exposure assessment model. We study local to global population exposure associated with emissions from 126 point sources matching locations of waste-to-energy plants across France. Results for three chemicals with distinct physicochemical properties are expressed as the evolution of the population intake fraction through inhalation and ingestion as a function of the distance from sources. For substances with atmospheric half-lives longer than a week, less than 20% of the global population intake through inhalation (median of 126 emission scenarios) can occur within a 100 km radius from the source. This suggests that, by neglecting distant low-level exposure, local assessments might only account for fractions of global cumulative intakes. We also study ∼10 000 emission locations covering France more densely to determine per chemical and exposure route which locations minimize global intakes. Maps of global intake fractions associated with each emission location show clear patterns associated with population and agriculture production densities.

Contemporary morphological diversification of passerine birds introduced to the Hawaiian archipelago.

PubMed

Mathys, Blake A; Lockwood, Julie L

2011-08-07

Species that have been introduced to islands experience novel and strong selection pressures after establishment. There is evidence that exotic species diverge from their native source populations; further, a few studies have demonstrated adaptive divergence across multiple exotic populations of a single species. Exotic birds provide a good study system, as they have been introduced to many locations worldwide, and we often know details concerning the propagule origin, time of introduction, and dynamics of establishment and dispersal within the introduced range. These data make them especially conducive to the examination of contemporary evolution. Island faunas have received intense scrutiny, therefore we have expectations concerning the patterns of diversification for exotic species. We examine six passerine bird species that were introduced to the Hawaiian archipelago less than 150 years ago. We find that five of these show morphological divergence among islands from the time since they were established. We demonstrate that some of this divergence cannot be accounted for by genetic drift, and therefore we must consider adaptive evolution to explain it. We also evaluate evolutionary divergence rates and find that these species are diverging at similar rates to those found in published studies of contemporary evolution in native species.

Coming out of the starting blocks: extended lag time rearranges genetic diversity in introduced marine fishes of Hawai‘i

PubMed Central

Gaither, Michelle R.; Toonen, Robert J.; Bowen, Brian W.

2012-01-01

Biological invasions with known histories are rare, especially in the sea, and empirical studies of the genetic consequences are even rarer. Fifty-five years ago, the state of Hawai‘i began a remarkable, if unintentional, ‘experiment’ with the introduction of three reef fishes, Lutjanus fulvus, Cephalopholis argus and Lutjanus kasmira. All have since expanded from the initial introduction of 2204 to 3163 individuals; however, historical records show that initially L. fulvus remained scarce, C. argus had modest population expansion and L. kasmira experienced rapid population growth. The consequences of differential population growth rates are apparent in F-statistics: Hawaiian L. fulvus demonstrate strong and significant haplotype frequency shifts from the founder location (FST = 0.449), C. argus shows low but significant differentiation (FST = 0.066) and L. kasmira is nearly identical to the founder location (FST = 0.008). All three species had higher mtDNA diversity in the introduced range, which can be explained by multiple sources for L. fulvus and L. kasmira, but not for C. argus. We conclude that lag time before population expansion, in conjunction with genetic drift, has defined the genetic architecture of these three species in the introduced range. PMID:22874747

Three genetic groups of the Eucalyptus stem canker pathogen Teratosphaeria zuluensis introduced into Africa from an unknown source.

PubMed

Jimu, Luke; Chen, ShuaiFei; Wingfield, Michael J; Mwenje, Eddie; Roux, Jolanda

2016-01-01

The Eucalyptus stem canker pathogen Teratosphaeria zuluensis was discovered in South Africa in 1988 and it has subsequently been found in several other African countries as well as globally. In this study, the population structure, genetic diversity and evolutionary history of T. z uluensis were analysed using microsatellite markers to gain an enhanced understanding of its movement in Africa. Isolates were collected from several sites in Malawi, Mozambique, Uganda and Zambia. Data obtained were compared with those previously published for a South African population. The data obtained from 334 isolates, amplified across eight microsatellite loci, were used for assignment, differentiation and genetic diversity tests. STRUCTURE analyses, θ st and genetic distances revealed the existence of two clusters, one dominated by isolates from South Africa and the other by isolates from the Zambezi basin including Malawi, Mozambique and Zambia. High levels of admixture were found within and among populations, dominated by the Mulanje population in Malawi. Moderate to low genetic diversity of the populations supports the previously held view that the pathogen was introduced into Africa. The clonal nature of the Ugandan population suggests a very recent introduction, most likely from southern Africa.

Restoration over time and sustainability of Schinus terebinthifolius Raddi.

PubMed

Álvares-Carvalho, S V; Silva-Mann, R; Gois, I B; Melo, M F V; Oliveira, A S; Ferreira, R A; Gomes, L J

2017-05-31

The success of recovery programs on degraded areas is dependent on the genetic material to be used, which should present heterozygosity and genetic diversity in native and recovered populations. This study was carried out to evaluate the model efficiency to enable the recovery of a degraded area of the Lower São Francisco, Sergipe, Brazil. The target species for this study was Schinus terebinthifolius Raddi. Three populations were analyzed, the recovered area, seed-tree source population, and native tree population border established to the recovered area. The random amplified polymorphic DNA (RAPD) markers were used for diversity analysis. Genetic structure was estimated to evaluate the level of genetic variability existent in each population. There was no correlation between the spatial distribution and the genetic distances for all trees of the recovered area. The heterozygosity present in the recovered population was higher than the native tree population. The seed-tree source population presents genetic bottlenecks. Three clusters were suggested (ΔK = 3) with non-genetic structure. High intra-population genetic variability and inter-population differentiation are present. However, gene flow may also introduce potentially adaptive alleles in the populations of the recovered area, and the native population is necessary to ensure the sustainability and maintenance of the populations by allelic exchange.

Fish introductions in the former Soviet Union: The Sevan trout (Salmo ischchan) — 80 years later

PubMed Central

Bogdanowicz, Wiesław; Rutkowski, Robert; Gabrielyan, Bardukh K.; Ryspaev, Akylbek; Asatryan, Anzhela N.; Mkrtchyan, Jon A.; Bujalska, Barbara M.

2017-01-01

The Soviet Union played the leading role in fish introductions in Eurasia. However, only 3% of all introductions prior to 1978 gave a commercial benefit. One of the noteworthy examples appears to be the Sevan trout (Salmo ischchan Kessler, 1877)—an endemic salmonid of Lake Sevan in Armenia. This species has been introduced to Kirghizstan, Kazakhstan, and Uzbekistan, however, only the Kirghiz population has persisted in relatively high numbers. In this paper we provide the first extensive molecular study of S. ischchan using samples from the native population from Lake Sevan and three hatcheries in Armenia, as well as from the population introduced to Lake Issyk Kul in Kirghizstan. The Kirghiz population has been isolated since the introductions took place in 1930 and 1936. Our results, based on 11 nuclear microsatellites and a 905 bp fragment of the mitochondrial control region suggest that hatcheries have maintained genetic variability by way of ongoing translocations of individuals from Lake Sevan. Simultaneously, significant Garza-Williamson M-values suggest that bottlenecks could have reduced the genetic variability of the wild populations in the past. This hypothesis is supported by historical data, indicating highly manipulated water-level regulations and poaching as two main factors that dramatically impact fish abundance in the lake. On the other hand, a similar situation has been observed in Kirghizstan, but this population likely rebounded from small population size faster than the other populations examined. The Kirghiz population is significantly genetically differentiated from the other groups and have morphological features and biological attributes not observed in the source population. Genetic data imply that the effective population size in the native population is lower than that found in the introduced population, suggesting that some active protection of the Lake Sevan population may be needed urgently. PMID:28683097

Deciphering the Routes of invasion of Drosophila suzukii by Means of ABC Random Forest.

PubMed

Fraimout, Antoine; Debat, Vincent; Fellous, Simon; Hufbauer, Ruth A; Foucaud, Julien; Pudlo, Pierre; Marin, Jean-Michel; Price, Donald K; Cattel, Julien; Chen, Xiao; Deprá, Marindia; François Duyck, Pierre; Guedot, Christelle; Kenis, Marc; Kimura, Masahito T; Loeb, Gregory; Loiseau, Anne; Martinez-Sañudo, Isabel; Pascual, Marta; Polihronakis Richmond, Maxi; Shearer, Peter; Singh, Nadia; Tamura, Koichiro; Xuéreb, Anne; Zhang, Jinping; Estoup, Arnaud

2017-04-01

Deciphering invasion routes from molecular data is crucial to understanding biological invasions, including identifying bottlenecks in population size and admixture among distinct populations. Here, we unravel the invasion routes of the invasive pest Drosophila suzukii using a multi-locus microsatellite dataset (25 loci on 23 worldwide sampling locations). To do this, we use approximate Bayesian computation (ABC), which has improved the reconstruction of invasion routes, but can be computationally expensive. We use our study to illustrate the use of a new, more efficient, ABC method, ABC random forest (ABC-RF) and compare it to a standard ABC method (ABC-LDA). We find that Japan emerges as the most probable source of the earliest recorded invasion into Hawaii. Southeast China and Hawaii together are the most probable sources of populations in western North America, which then in turn served as sources for those in eastern North America. European populations are genetically more homogeneous than North American populations, and their most probable source is northeast China, with evidence of limited gene flow from the eastern US as well. All introduced populations passed through bottlenecks, and analyses reveal five distinct admixture events. These findings can inform hypotheses concerning how this species evolved between different and independent source and invasive populations. Methodological comparisons indicate that ABC-RF and ABC-LDA show concordant results if ABC-LDA is based on a large number of simulated datasets but that ABC-RF out-performs ABC-LDA when using a comparable and more manageable number of simulated datasets, especially when analyzing complex introduction scenarios. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Quantifying the impact of woodpecker predation on population dynamics of the emerald ash borer (Agrilus planipennis)

USDA-ARS?s Scientific Manuscript database

The emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that has killed millions of ash trees since it was accidentally introduced to North America in the 1990s. Woodpeckers are an important source of mortality for EAB in their native range, and understanding their effect on the pop...

Characteristics of information available on fire and invasive plants in the eastern United States

Treesearch

Corey L. Gucker; Kris Zouhar; Jane Kapler Smith; Katharine R. Stone

2012-01-01

Wildland managers need detailed information about the responses of invasive species to fire and the conditions that increase site invasibility in order to effectively manage fire without introducing or increasing populations of invasive plants. Literature reviews and syntheses of original research are important sources of this information, but the usefulness of a...

An overview of confounding. Part 2: how to identify it and special situations.

PubMed

Howards, Penelope P

2018-04-01

Confounding biases study results when the effect of the exposure on the outcome mixes with the effects of other risk and protective factors for the outcome that are present differentially by exposure status. However, not all differences between the exposed and unexposed group cause confounding. Thus, sources of confounding must be identified before they can be addressed. Confounding is absent in an ideal study where all of the population of interest is exposed in one universe and is unexposed in a parallel universe. In an actual study, an observed unexposed population represents the unobserved parallel universe. Thinking about differences between this substitute population and the unexposed parallel universe helps identify sources of confounding. These differences can then be represented in a diagram that shows how risk and protective factors for the outcome are related to the exposure. Sources of confounding identified in the diagram should be addressed analytically and through study design. However, treating all factors that differ by exposure status as confounders without considering the structure of their relation to the exposure can introduce bias. For example, conditions affected by the exposure are not confounders. There are also special types of confounding, such as time-varying confounding and unfixable confounding. It is important to evaluate carefully whether factors of interest contribute to confounding because bias can be introduced both by ignoring potential confounders and by adjusting for factors that are not confounders. The resulting bias can result in misleading conclusions about the effect of the exposure of interest on the outcome. © 2018 Nordic Federation of Societies of Obstetrics and Gynecology.

Population structure of the banana weevil, an introduced pest in the Canary Islands, studied by RAPD analysis.

PubMed

Magaña, C; Beroiz, B; Hernández-Crespo, P; Montes de Oca, M; Carnero, A; Ortego, F; Castañera, P

2007-12-01

The banana weevil (BW), Cosmopolites sordidus (Coleoptera: Curculionidae), is one of the most important insect pests of bananas and plantains. The mobility and the origin of BW infestations at the Canary Islands (Tenerife, La Gomera and La Palma) have been analysed using Random Amplified Polymorphic DNA (RAPD) as molecular markers. Populations from Costa Rica, Colombia, Uganda and Madeira were also included for comparison. One hundred and fifteen reproducible bands from eight primers were obtained. The level of polymorphism in the populations from the Canary Islands (40-62%) was in the range of those found in other populations. Nei's genetic distances, pair-wise fixation index (FST) values indicate that the closest populations are Tenerife populations among themselves (Nei's genetic distance=0.054-0.100; FST=0.091-0.157) and Costa Rica and Colombia populations (Nei's genetic distance=0.049; FST=0.113). Our results indicate the existence of BW local biotypes with limited gene flow and affected by genetic drift. These results are compatible with a unique event of colonization at Tenerife; whereas, the outbreaks in La Gomera and La Palma may come from independent introductions. The Madeira population is phylogenetically and geographically closer to the Canary Islands populations, suggesting that it is the most likely source of the insects introduced in the Canary Islands.

Conclusions, synthesis, and future directions: understanding sources of population change

USGS Publications Warehouse

Esler, Daniel N.; Flint, Paul L.; Derksen, Dirk V.; Savard, Jean-Pierre L.; Eadie, John M.

2015-01-01

The material in this volume reflects the burgeoning interest in sea ducks, both as study species with compelling and unique ecological attributes and as taxa of conservation concern. In this review, we provide perspective on the current state of sea duck knowledge by highlighting key findings in the preceding chapters that are of particular value for understanding or influencing population change. We also introduce a conceptual model that characterizes links among topics covered by individual chapters and places them in the context of demographic responses. Finally, we offer recommendations for areas of future research that we suggest will have importance for understanding and managing sea duck population dynamics.

Computational Modeling of Single Neuron Extracellular Electric Potentials and Network Local Field Potentials using LFPsim.

PubMed

Parasuram, Harilal; Nair, Bipin; D'Angelo, Egidio; Hines, Michael; Naldi, Giovanni; Diwakar, Shyam

2016-01-01

Local Field Potentials (LFPs) are population signals generated by complex spatiotemporal interaction of current sources and dipoles. Mathematical computations of LFPs allow the study of circuit functions and dysfunctions via simulations. This paper introduces LFPsim, a NEURON-based tool for computing population LFP activity and single neuron extracellular potentials. LFPsim was developed to be used on existing cable compartmental neuron and network models. Point source, line source, and RC based filter approximations can be used to compute extracellular activity. As a demonstration of efficient implementation, we showcase LFPs from mathematical models of electrotonically compact cerebellum granule neurons and morphologically complex neurons of the neocortical column. LFPsim reproduced neocortical LFP at 8, 32, and 56 Hz via current injection, in vitro post-synaptic N2a, N2b waves and in vivo T-C waves in cerebellum granular layer. LFPsim also includes a simulation of multi-electrode array of LFPs in network populations to aid computational inference between biophysical activity in neural networks and corresponding multi-unit activity resulting in extracellular and evoked LFP signals.

Simulations indicate that scores of lionfish (Pterois volitans) colonized the Atlantic Ocean.

PubMed

Selwyn, Jason D; Johnson, John E; Downey-Wall, Alan M; Bynum, Adam M; Hamner, Rebecca M; Hogan, J Derek; Bird, Christopher E

2017-01-01

The invasion of the western Atlantic Ocean by the Indo-Pacific red lionfish ( Pterois volitans ) has had devastating consequences for marine ecosystems. Estimating the number of colonizing lionfish can be useful in identifying the introduction pathway and can inform policy decisions aimed at preventing similar invasions. It is well-established that at least ten lionfish were initially introduced. However, that estimate has not faced probabilistic scrutiny and is based solely on the number of haplotypes in the maternally-inherited mitochondrial control region. To rigorously estimate the number of lionfish that were introduced, we used a forward-time, Wright-Fisher, population genetic model in concert with a demographic, life-history model to simulate the invasion across a range of source population sizes and colonizing population fecundities. Assuming a balanced sex ratio and no Allee effects, the simulations indicate that the Atlantic population was founded by 118 (54-514, 95% HPD) lionfish from the Indo-Pacific, the Caribbean by 84 (22-328, 95% HPD) lionfish from the Atlantic, and the Gulf of Mexico by at least 114 (no upper bound on 95% HPD) lionfish from the Caribbean. Increasing the size, and therefore diversity, of the Indo-Pacific source population and fecundity of the founding population caused the number of colonists to decrease, but with rapidly diminishing returns. When the simulation was parameterized to minimize the number of colonists (high θ and relative fecundity), 96 (48-216, 95% HPD) colonists were most likely. In a more realistic scenario with Allee effects (e.g., 50% reduction in fecundity) plaguing the colonists, the most likely number of lionfish increased to 272 (106-950, 95% HPD). These results, in combination with other published data, support the hypothesis that lionfish were introduced to the Atlantic via the aquarium trade, rather than shipping. When building the model employed here, we made assumptions that minimize the number of colonists, such as the lionfish being introduced in a single event. While we conservatively modelled the introduction pathway as a single release of lionfish in one location, it is more likely that a combination of smaller and larger releases from a variety of aquarium trade stakeholders occurred near Miami, Florida, which could have led to even larger numbers of colonists than simulated here. Efforts to prevent future invasions via the aquarium trade should focus on the education of stakeholders and the prohibition of release, with adequate rewards for compliance and penalties for violations.

Simulations indicate that scores of lionfish (Pterois volitans) colonized the Atlantic Ocean

PubMed Central

Selwyn, Jason D.; Johnson, John E.; Downey-Wall, Alan M.; Bynum, Adam M.; Hamner, Rebecca M.; Hogan, J. Derek

2017-01-01

The invasion of the western Atlantic Ocean by the Indo-Pacific red lionfish (Pterois volitans) has had devastating consequences for marine ecosystems. Estimating the number of colonizing lionfish can be useful in identifying the introduction pathway and can inform policy decisions aimed at preventing similar invasions. It is well-established that at least ten lionfish were initially introduced. However, that estimate has not faced probabilistic scrutiny and is based solely on the number of haplotypes in the maternally-inherited mitochondrial control region. To rigorously estimate the number of lionfish that were introduced, we used a forward-time, Wright-Fisher, population genetic model in concert with a demographic, life-history model to simulate the invasion across a range of source population sizes and colonizing population fecundities. Assuming a balanced sex ratio and no Allee effects, the simulations indicate that the Atlantic population was founded by 118 (54–514, 95% HPD) lionfish from the Indo-Pacific, the Caribbean by 84 (22–328, 95% HPD) lionfish from the Atlantic, and the Gulf of Mexico by at least 114 (no upper bound on 95% HPD) lionfish from the Caribbean. Increasing the size, and therefore diversity, of the Indo-Pacific source population and fecundity of the founding population caused the number of colonists to decrease, but with rapidly diminishing returns. When the simulation was parameterized to minimize the number of colonists (high θ and relative fecundity), 96 (48–216, 95% HPD) colonists were most likely. In a more realistic scenario with Allee effects (e.g., 50% reduction in fecundity) plaguing the colonists, the most likely number of lionfish increased to 272 (106–950, 95% HPD). These results, in combination with other published data, support the hypothesis that lionfish were introduced to the Atlantic via the aquarium trade, rather than shipping. When building the model employed here, we made assumptions that minimize the number of colonists, such as the lionfish being introduced in a single event. While we conservatively modelled the introduction pathway as a single release of lionfish in one location, it is more likely that a combination of smaller and larger releases from a variety of aquarium trade stakeholders occurred near Miami, Florida, which could have led to even larger numbers of colonists than simulated here. Efforts to prevent future invasions via the aquarium trade should focus on the education of stakeholders and the prohibition of release, with adequate rewards for compliance and penalties for violations. PMID:29302383

Selection of energy source and evolutionary stable strategies for power plants under financial intervention of government

NASA Astrophysics Data System (ADS)

Hafezalkotob, Ashkan; Mahmoudi, Reza

2017-09-01

Currently, many socially responsible governments adopt economic incentives and deterrents to manage environmental impacts of electricity suppliers. Considering the Stackelberg leadership of the government, the government's role in the competition of power plants in an electricity market is investigated. A one-population evolutionary game model of power plants is developed to study how their production strategy depends on tariffs levied by the government. We establish that a unique evolutionary stable strategy (ESS) for the population exists. Numerical examples demonstrate that revenue maximization and environment protection policies of the government significantly affect the production ESS of competitive power plants. The results reveal that the government can introduce a green energy source as an ESS of the competitive power plants by imposing appropriate tariffs.

Let’s not forget the biodiversity of the cities

Treesearch

A.E. Lugo

2010-01-01

Cities contain over half of the world’s population and are the source of many anthropogenic effects on the world’s biota. Close examination of San Juan, Puerto Rico, a tropical city, reveals a significant green infrastructure. The city contains natural and human-constructed forests, urban aquatic systems with native and introduced species, and a thriving and diverse...

Larvivorous fish for preventing malaria transmission

PubMed Central

Walshe, Deirdre P; Garner, Paul; Adeel, Ahmed A; Pyke, Graham H; Burkot, Thomas R

2017-01-01

Background Adult female Anopheles mosquitoes can transmit Plasmodium parasites that cause malaria. Some fish species eat mosquito larvae and pupae. In disease control policy documents, the World Health Organization (WHO) includes biological control of malaria vectors by stocking ponds, rivers, and water collections near where people live with larvivorous fish to reduce Plasmodium parasite transmission. In the past, the Global Fund has financed larvivorous fish programmes in some countries, and, with increasing efforts in eradication of malaria, policymakers may return to this option. Therefore, we assessed the evidence base for larvivorous fish programmes in malaria control. Objectives To evaluate whether introducing larvivorous fish to anopheline larval habitats impacts Plasmodium parasite transmission. We also sought to summarize studies that evaluated whether introducing larvivorous fish influences the density and presence of Anopheles larvae and pupae in water sources. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE (PubMed); Embase (Ovid); CABS Abstracts; LILACS; and the metaRegister of Controlled Trials (mRCT) up to 6 July 2017. We checked the reference lists of all studies identified by the search. We examined references listed in review articles and previously compiled bibliographies to look for eligible studies. Also we contacted researchers in the field and the authors of studies that met the inclusion criteria for additional information regarding potential studies for inclusion and ongoing studies. This is an update of a Cochrane Review published in 2013. Selection criteria Randomized controlled trials (RCTs) and non-RCTs, including controlled before-and-after studies, controlled time series, and controlled interrupted time series studies from malaria-endemic regions that introduced fish as a larvicide and reported on malaria in the community or the density of the adult anopheline population. In the absence of direct evidence of an effect on transmission, we performed a secondary analysis on studies that evaluated the effect of introducing larvivorous fish on the density or presence of immature anopheline mosquitoes (larvae and pupae forms) in water sources to determine whether this intervention has any potential that may justify further research in the control of malaria vectors. Data collection and analysis Two review authors independently screened each article by title and abstract, and examined potentially relevant studies for inclusion using an eligibility form. At least two review authors independently extracted data and assessed risk of bias of included studies. If relevant data were unclear or were not reported, we contacted the study authors for clarification. We presented data in tables, and we summarized studies that evaluated the effects of introducing fish on anopheline immature density or presence, or both. We used the GRADE approach to summarize the certainty of the evidence. We also examined whether the included studies reported any possible adverse impact of introducing larvivorous fish on non-target native species. Main results We identified no studies that reported the effects of introducing larvivorous fish on the primary outcomes of this review: malaria infection in nearby communities, entomological inoculation rate, or on adult Anopheles density. For the secondary analysis, we examined the effects of introducing larvivorous fish on the density and presence of anopheline larvae and pupae in community water sources, and found 15 small studies with a follow-up period between 22 days and five years. These studies were undertaken in Sri Lanka (two studies), India (three studies), Ethiopia (one study), Kenya (two studies), Sudan (one study), Grande Comore Island (one study), Korea (two studies), Indonesia (one study), and Tajikistan (two studies). These studies were conducted in a variety of settings, including localized water bodies (such as wells, domestic water containers, fishponds, and pools (seven studies); riverbed pools below dams (two studies)); rice field plots (five studies); and water canals (two studies). All included studies were at high risk of bias. The research was insufficient to determine whether larvivorous fish reduce the density of Anopheles larvae and pupae (12 studies, unpooled data, very low certainty evidence). Some studies with high stocking levels of fish seemed to arrest the increase in immature anopheline populations, or to reduce the number of immature anopheline mosquitoes, compared with controls. However, this finding was not consistent, and in studies that showed a decrease in immature anopheline populations, the effect was not always consistently sustained. In contrast, some studies reported larvivorous fish reduced the number of water sources withAnopheles larvae and pupae (five studies, unpooled data, low certainty evidence). None of the included studies reported effects of larvivorous fish on local native fish populations or other species. Authors' conclusions We do not know whether introducing larvivorous fish reduces malaria transmission or the density of adult anopheline mosquito populations. In research studies that examined the effects on immature anopheline stages of introducing fish to potential malaria vector larval habitats, high stocking levels of fish may reduce the density or presence of immature anopheline mosquitoes in the short term. We do not know whether this translates into impact on malaria transmission. Our interpretation of the current evidence is that countries should not invest in fish stocking as a stand alone or supplementary larval control measure in any malaria transmission areas outside the context of research using carefully controlled field studies or quasi-experimental designs. Such research should examine the effects on native fish and other non-target species. Fish that feed on mosquito larvae for preventing malaria transmission What is the aim of this review? Adult female Anopheles mosquitoes transmit the Plasmodium parasites that cause malaria. The aim of this Cochrane Review was to evaluate whether introducing fish that eat mosquito larvae and pupae (early life stages of mosquitoes) into water sources near where people live will decrease the adult Anopheles mosquito population and thus the number of people infected with Plasmodium parasites. Key messages We do not know if introducing fish that eat mosquito larvae and pupae has an impact on the number of people with malaria or on the adult Anopheles mosquito population. What was studied in the review? The review authors examined the available research that evaluated introducing fish that eat larvae ('larvivorous') to Anopheles mosquito larval habitats in areas where malaria was common. Fifteen small studies looked at the effects of larvivorous fish on Anopheles larvae and pupae in different larval habitats, including localized water bodies (such as wells, domestic water containers, fishponds, and pools; seven studies), riverbed pools below dams (two studies), rice field plots (four studies), and water canals (two studies). These studies were undertaken in Sri Lanka (two studies), India (three studies), Ethiopia (one study), Kenya (two studies), Sudan (one study), Grande Comore Island (one study), Korea (two studies), Indonesia (one study), and Tajikistan (two studies). This is an update of a 2013 Cochrane Review and includes some older unpublished studies from Tajikistan and a new trial from India. What are the main results of the review? In our main analysis, we found no studies that looked at the effects of larvivorous fish on adult Anopheles mosquito populations or on the number of people infected with Plasmodium parasites. In our analysis exploring the effect of fish introduction on the number of Anopheles larvae and pupae in water collections, these studies produced inconsistent results on immature mosquito density (12 studies, unpooled data, very low certainty evidence). Some studies that measured the number of water sources withAnopheles larvae and pupae reported a reduction in the number of sites with Anopheles larvae and pupae after introducing fish (five studies, unpooled data, low certainty evidence). None of the included studies examined the effects of introducing larvivorous fish on other native species present, but these studies were not designed to do this. All included studies were at high risk of bias. Before much is invested in this intervention, we need better research to determine the effect of introducing larvivorous fish on the number of people infected with malaria, and on adult Anopheles populations. Researchers need to use robust controlled designs with an adequate number of sites. In addition, researchers should explore the potential harms from introducing these fish on native fish and other non-Anopheles species. How up-to-date is this review? The review authors searched for studies published up to 6 July 2017. PMID:29226959

Detecting black bear source–sink dynamics using individual-based genetic graphs

PubMed Central

Draheim, Hope M.; Moore, Jennifer A.; Etter, Dwayne; Winterstein, Scott R.; Scribner, Kim T.

2016-01-01

Source–sink dynamics affects population connectivity, spatial genetic structure and population viability for many species. We introduce a novel approach that uses individual-based genetic graphs to identify source–sink areas within a continuously distributed population of black bears (Ursus americanus) in the northern lower peninsula (NLP) of Michigan, USA. Black bear harvest samples (n = 569, from 2002, 2006 and 2010) were genotyped at 12 microsatellite loci and locations were compared across years to identify areas of consistent occupancy over time. We compared graph metrics estimated for a genetic model with metrics from 10 ecological models to identify ecological factors that were associated with sources and sinks. We identified 62 source nodes, 16 of which represent important source areas (net flux > 0.7) and 79 sink nodes. Source strength was significantly correlated with bear local harvest density (a proxy for bear density) and habitat suitability. Additionally, resampling simulations showed our approach is robust to potential sampling bias from uneven sample dispersion. Findings demonstrate black bears in the NLP exhibit asymmetric gene flow, and individual-based genetic graphs can characterize source–sink dynamics in continuously distributed species in the absence of discrete habitat patches. Our findings warrant consideration of undetected source–sink dynamics and their implications on harvest management of game species. PMID:27440668

How much gene flow is needed to avoid inbreeding depression in wild tiger populations?

PubMed Central

Kenney, John; Allendorf, Fred W.; McDougal, Charles; Smith, James L. D.

2014-01-01

The number and size of tiger populations continue to decline owing to habitat loss, habitat fragmentation and poaching of tigers and their prey. As a result, tiger populations have become small and highly structured. Current populations have been isolated since the early 1970s or for approximately seven generations. The objective of this study is to explore how inbreeding may be affecting the persistence of remaining tiger populations and how dispersal, either natural or artificial, may reduce the potentially detrimental effect of inbreeding depression. We developed a tiger simulation model and used published levels of genetic load in mammals to simulate inbreeding depression. Following a 50 year period of population isolation, we introduced one to four dispersing male tigers per generation to explore how gene flow from nearby populations may reduce the negative impact of inbreeding depression. For the smallest populations, even four dispersing male tigers per generation did not increase population viability, and the likelihood of extinction is more than 90% within 30 years. Unless habitat connectivity is restored or animals are artificially introduced in the next 70 years, medium size wild populations are also likely to go extinct, with only four to five of the largest wild tiger populations likely to remain extant in this same period without intervention. To reduce the risk of local extinction, habitat connectivity must be pursued concurrently with efforts to increase population size (e.g. enhance habitat quality, increase habitat availability). It is critical that infrastructure development, dam construction and other similar projects are planned appropriately so that they do not erode the extent or quality of habitat for these populations so that they can truly serve as future source populations. PMID:24990671

How much gene flow is needed to avoid inbreeding depression in wild tiger populations?

PubMed

Kenney, John; Allendorf, Fred W; McDougal, Charles; Smith, James L D

2014-08-22

The number and size of tiger populations continue to decline owing to habitat loss, habitat fragmentation and poaching of tigers and their prey. As a result, tiger populations have become small and highly structured. Current populations have been isolated since the early 1970s or for approximately seven generations. The objective of this study is to explore how inbreeding may be affecting the persistence of remaining tiger populations and how dispersal, either natural or artificial, may reduce the potentially detrimental effect of inbreeding depression. We developed a tiger simulation model and used published levels of genetic load in mammals to simulate inbreeding depression. Following a 50 year period of population isolation, we introduced one to four dispersing male tigers per generation to explore how gene flow from nearby populations may reduce the negative impact of inbreeding depression. For the smallest populations, even four dispersing male tigers per generation did not increase population viability, and the likelihood of extinction is more than 90% within 30 years. Unless habitat connectivity is restored or animals are artificially introduced in the next 70 years, medium size wild populations are also likely to go extinct, with only four to five of the largest wild tiger populations likely to remain extant in this same period without intervention. To reduce the risk of local extinction, habitat connectivity must be pursued concurrently with efforts to increase population size (e.g. enhance habitat quality, increase habitat availability). It is critical that infrastructure development, dam construction and other similar projects are planned appropriately so that they do not erode the extent or quality of habitat for these populations so that they can truly serve as future source populations. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Critically evaluating best management practices for preventing freshwater turtle extinctions.

PubMed

Spencer, R-J; Van Dyke, J U; Thompson, Michael B

2017-12-01

Ex situ conservation tools, such as captive breeding for reintroduction, are considered a last resort to recover threatened or endangered species, but they may also help reduce anthropogenic threats where it is difficult or impossible to address them directly. Headstarting, or captive rearing of eggs or neonate animals for subsequent release into the wild, is controversial because it treats only a symptom of a larger conservation problem; however, it may provide a mechanism to address multiple threats, particularly near population centers. We conducted a population viability analysis of Australia's most widespread freshwater turtle, Chelodina longicollis, to determine the effect of adult roadkill (death by collision with motor vehicles), which is increasing, and reduced recruitment through nest predation from introduced European red foxes (Vulpes vulpes). We also modeled management scenarios to test the effectiveness of headstarting, fox management, and measures to reduce mortality on roads. Only scenarios with headstarting from source populations eliminated all risks of extinction and allowed population growth. Small increases in adult mortality (2%) had the greatest effect on population growth and extinction risk. Where threats simultaneously affected other life-history stages (e.g., recruitment), eliminating harvest pressures on adult females alone did not eliminate the risk of population extinction. In our models, one source population could supply enough hatchlings annually to supplement 25 other similar-sized populations such that extinction was avoided. Based on our results, we believe headstarting should be a primary tool for managing freshwater turtles for which threats affect multiple life-history stages. We advocate the creation of source populations for managing freshwater turtles that are greatly threatened at multiple life-history stages, such as depredation of eggs by invasive species and adult mortality via roadkill. © 2017 Society for Conservation Biology.

Genetic structure provides insights into the geographic origins and temporal change in the invasive charru mussel (Sururu) in the southeastern United States

PubMed Central

Walters, Linda J.; Fernandes, Flavio C.; Ferreira, Carlos E. L.

2017-01-01

In 2004, Mytella charruana (d'Orbigny, 1842) (Mollusca: Bivalvia: Mytilidae) became established along the coast of the southeastern United States (SE-US). Using mitochondrial DNA sequencing (cytochrome c oxidase subunit I), we compared genetic variation throughout its native range in South America to its invasive range in the SE-US. Samples from the SE-US were collected in 2006 and 2010 enabling a temporal comparison to evaluate possible genetic changes of the invasive population. We addressed two questions. First, what are the potential source populations (or geographic regions) for the SE-US invasion? Second, how has genetic diversity changed between the two sampling periods within the SE-US? We identified a total of 72 haplotypes, 64 of which were isolated to geographic sites and only 8 were shared among sites. The highly structured native range provides insight into the origin of invasive populations where our results suggest that the introduced SE-US population originated from multiple source populations with the Panama region as the primary source. Additionally, our results indicate that genetic composition of the non-native populations was unchanged between the two sampling periods. Mytella charruana exhibit a significant pattern of genetic structure among natural populations, owing to biogeographic barriers that limit natural dispersal, and an ability to persist in novel habitats, owing to a suite of life-history characters that favor survival under variable conditions. Overall, this study explains why M. charruana may become an increasing threat to locations founded by anthropogenic transportation. PMID:28686694

Revealing unobserved factors underlying cortical activity with a rectified latent variable model applied to neural population recordings.

PubMed

Whiteway, Matthew R; Butts, Daniel A

2017-03-01

The activity of sensory cortical neurons is not only driven by external stimuli but also shaped by other sources of input to the cortex. Unlike external stimuli, these other sources of input are challenging to experimentally control, or even observe, and as a result contribute to variability of neural responses to sensory stimuli. However, such sources of input are likely not "noise" and may play an integral role in sensory cortex function. Here we introduce the rectified latent variable model (RLVM) in order to identify these sources of input using simultaneously recorded cortical neuron populations. The RLVM is novel in that it employs nonnegative (rectified) latent variables and is much less restrictive in the mathematical constraints on solutions because of the use of an autoencoder neural network to initialize model parameters. We show that the RLVM outperforms principal component analysis, factor analysis, and independent component analysis, using simulated data across a range of conditions. We then apply this model to two-photon imaging of hundreds of simultaneously recorded neurons in mouse primary somatosensory cortex during a tactile discrimination task. Across many experiments, the RLVM identifies latent variables related to both the tactile stimulation as well as nonstimulus aspects of the behavioral task, with a majority of activity explained by the latter. These results suggest that properly identifying such latent variables is necessary for a full understanding of sensory cortical function and demonstrate novel methods for leveraging large population recordings to this end. NEW & NOTEWORTHY The rapid development of neural recording technologies presents new opportunities for understanding patterns of activity across neural populations. Here we show how a latent variable model with appropriate nonlinear form can be used to identify sources of input to a neural population and infer their time courses. Furthermore, we demonstrate how these sources are related to behavioral contexts outside of direct experimental control. Copyright © 2017 the American Physiological Society.

Larvivorous fish for preventing malaria transmission.

PubMed

Walshe, Deirdre P; Garner, Paul; Abdel-Hameed Adeel, Ahmed A; Pyke, Graham H; Burkot, Tom

2013-12-10

Adult anopheline mosquitoes transmit Plasmodium parasites that cause malaria. Some fish species eat mosquito larvae and pupae. In disease control policy documents, the World Health Organization includes biological control of malaria vectors by stocking ponds, rivers, and water collections near where people live with larvivorous fish to reduce Plasmodium parasite transmission. The Global Fund finances larvivorous fish programmes in some countries, and, with increasing efforts in eradication of malaria, policy makers may return to this option. We therefore assessed the evidence base for larvivorous fish programmes in malaria control. Our main objective was to evaluate whether introducing larvivorous fish to anopheline breeding sites impacts Plasmodium parasite transmission. Our secondary objective was to summarize studies evaluating whether introducing larvivorous fish influences the density and presence of Anopheles larvae and pupae in water sources, to understand whether fish can possibly have an effect. We attempted to identify all relevant studies regardless of language or publication status (published, unpublished, in press, or ongoing). We searched the following databases: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; CABS Abstracts; LILACS; and the metaRegister of Controlled Trials (mRCT) until 18 June 2013. We checked the reference lists of all studies identified by the above methods. We also examined references listed in review articles and previously compiled bibliographies to look for eligible studies. Randomized controlled trials and non-randomized controlled trials, including controlled before-and-after studies, controlled time series and controlled interrupted time series studies from malaria-endemic regions that introduced fish as a larvicide and reported on malaria in the community or the density of the adult anopheline population. In the absence of direct evidence of an effect on transmission, we carried out a secondary analysis on studies that evaluated the effect of introducing larvivorous fish on the density or presence of immature anopheline mosquitoes (larvae and pupae forms) in community water sources to determine whether this intervention has any potential in further research on control of malaria vectors. Three review authors screened abstracts and examined potentially relevant studies by using an eligibility form. Two review authors independently extracted data and assessed risk of bias of included studies. If relevant data were unclear or were not reported, we wrote to the trial authors for clarification. We presented data in tables, and we summarized studies that evaluated the effects of fish introduction on anopheline immature density or presence, or both. We used GRADE to summarize evidence quality. We also examined whether the authors of included studies reported on any possible adverse impact of larvivorous fish introduction on non-target native species. We found no reliable studies that reported the effects of introducing larvivorous fish on malaria infection in nearby communities, on entomological inoculation rate, or on adult Anopheles density.For the secondary analysis, we examined the effects of introducing larvivorous fish on the density and presence of anopheline larvae and pupae in community water sources. We included 12 small studies, with follow-up from 22 days to five years. Studies were conducted in a variety of settings, including localized water bodies (such as wells, domestic water containers, fishponds, and pools; six studies), riverbed pools below dams (two studies), rice field plots (three studies), and water canals (two studies). All studies were at high risk of bias.The research was insufficient to determine whether larvivorous fish reduce the density of Anopheles larvae and pupae (nine studies, unpooled data, very low quality evidence). Some studies with high stocking levels of fish seemed to arrest the increase in immature anopheline populations, or to reduce the number of immature anopheline mosquitoes, compared with controls. However, this finding was not consistent, and in studies that showed a decrease in immature anopheline populations, the effect was not consistently sustained. Larvivorous fish may reduce the number of water sources with Anopheles larvae and pupae (five studies, unpooled data, low quality evidence).None of the included studies reported effects of larvivorous fish on local native fish populations or other species. Reliable research is insufficient to show whether introducing larvivorous fish reduces malaria transmission or the density of adult anopheline mosquito populations.In research examining the effects on immature anopheline stages of introducing fish to potential malaria vector breeding sites (localized water bodies such as wells and domestic water sources, rice field plots, and water canals) weak evidence suggests an effect on the density or presence of immature anopheline mosquitoes with high stocking levels of fish, but this finding is by no means consistent. We do not know whether this translates into health benefits, either with fish alone or with fish combined with other vector control measures. Our interpretation of the current evidence is that countries should not invest in fish stocking as a larval control measure in any malaria transmission areas outside the context of carefully controlled field studies or quasi-experimental designs. Research could also usefully examine the effects on native fish and other non-target species.

Multiple origins and incursions of the Atlantic barnacle Chthamalus proteus in the Pacific.

PubMed

Zardus, John D; Hadfield, Michael G

2005-10-01

Chthamalus proteus, a barnacle native to the Caribbean and western Atlantic, was introduced to the Pacific within the last few decades. Using direct sequencing of mitochondrial DNA (COI), we characterized genetic variation in native and introduced populations and searched for genetic matches between regions to determine if there were multiple geographical sources and introduction points for this barnacle. In the native range, we found great genetic differences among populations (max. F(ST) = 0.613) encompassing four lineages: one endemic to Panama, one endemic to Brazil, and two occurring Caribbean-wide. All four lineages were represented in the Pacific, but not equally; the Brazilian lineage was most prevalent and the Panamanian least common. Twenty-one individuals spread among nearly every island from where the barnacle is known in the Pacific, exactly matched six haplotypes scattered among Curaçao, the Netherlands Antilles; St John, US Virgin Islands; Puerto Rico; and Brazil, confirming a multigeographical origin for the Pacific populations. Significant genetic differences were also found in introduced populations from the Hawaiian Islands (F(CT) = 0.043, P < 0.001), indicating introduction events have occurred at more than one locality. However, the sequence, timing and number of arrival events remains unknown. Possible reasons for limited transport of this barnacle through the Panama Canal are discussed. This and a preponderance of Brazilian-type individuals in the Pacific suggest an unexpected route of entry from around Cape Horn, South America. Unification in the Pacific of historically divergent lineages of this barnacle raises the possibility for selection of 'hybrids' with novel ecological adaptations in its new environment.

Significant genetic differentiation between native and introduced silver carp (Hypophthalmichthys molitrix) inferred from mtDNA analysis

USGS Publications Warehouse

Li, S.-F.; Xu, J.-W.; Yang, Q.-L.; Wang, C.H.; Chapman, D.C.; Lu, G.

2011-01-01

Silver carp Hypophthalmichthys molitrix (Cyprinidae) is native to China and has been introduced to over 80 countries. The extent of genetic diversity in introduced silver carp and the genetic divergence between introduced and native populations remain largely unknown. In this study, 241 silver carp sampled from three major native rivers and two non-native rivers (Mississippi River and Danube River) were analyzed using nucleotide sequences of mitochondrial COI gene and D-loop region. A total of 73 haplotypes were observed, with no haplotype found common to all the five populations and eight haplotypes shared by two to four populations. As compared with introduced populations, all native populations possess both higher haplotype diversity and higher nucleotide diversity, presumably a result of the founder effect. Significant genetic differentiation was revealed between native and introduced populations as well as among five sampled populations, suggesting strong selection pressures might have occurred in introduced populations. Collectively, this study not only provides baseline information for sustainable use of silver carp in their native country (i.e., China), but also offers first-hand genetic data for the control of silver carp in countries (e.g., the United States) where they are considered invasive.

Population genomic analyses reveal a history of range expansion and trait evolution across the native and invaded range of yellow starthistle (Centaurea solstitialis)

PubMed Central

BARKER, BRITTANY S.; ANDONIAN, KRIKOR; SWOPE, SARAH M.; LUSTER, DOUGLAS G.; DLUGOSCH, KATRINA M.

2017-01-01

Identifying sources of genetic variation and reconstructing invasion routes for non-native introduced species is central to understanding the circumstances under which they may evolve increased invasiveness. In this study, we used genome-wide single nucleotide polymorphisms to study the colonization history of Centaurea solstitialis in its native range in Eurasia and invasions into the Americas. We leveraged this information to pinpoint key evolutionary shifts in plant size, a focal trait associated with invasiveness in this species. Our analyses revealed clear population genomic structure of potential source populations in Eurasia, including deep differentiation of a lineage found in the southern Apennine and Balkan Peninsulas and divergence among populations in Asia, eastern Europe, and western Europe. We found strongest support for an evolutionary scenario in which western European populations were derived from an ancient admixture event between populations from eastern Europe and Asia, and subsequently served as the main genetic ‘bridgehead’ for introductions to the Americas. Introductions to California appear to be from a single source region, and multiple, independent introductions of divergent genotypes likely occurred into the Pacific Northwest. Plant size has evolved significantly at three points during range expansion, including a large size increase in the lineage responsible for the aggressive invasion of California’s interior. These results reveal a long history of colonization, admixture, and trait evolution in C. solstitialis, and suggest routes for improving evidence-based management decisions for one of the most ecologically and economically damaging invasive species in the western United States. PMID:28029713

Wealth status and sex differential of household head: implication for source of drinking water in Nigeria.

PubMed

Morakinyo, Oyewale Mayowa; Adebowale, Stephen Ayo; Oloruntoba, Elizabeth Omoladun

2015-01-01

Source of potable water has implication on the population health. Availability of Improved Drinking Water Sources (IDWS) is a problem in developing countries, but variation exists across segments of the population. This study therefore examined the relationship between wealth status, sex of household head and source of potable water. The 2013 Nigeria Demographic and Health Survey data was used. A representative sample of 40,680 households was selected for the survey, with a minimum target of 943 completed interviews per state covering the entire population residing in non-institutional dwelling units in the country. Households where information on drinking water sources was not reported were excluded, thus reducing the sample to 38021. The dependent and key independent variables were IDWS and Wealth Index respectively. Data were analysed using Chi-square and binary logistic regression (α = .05). Households that used IDWS were headed by females (66.7 %) than males (58.7 %). Highest proportion of households who used IDWS was found in the rich wealth index group (76.7 %). The likelihood of using IDWS was higher in household headed by females (OR = 1.41; C.I = 1.33-1.49, p <0.001). Households that belong to rich wealth index and middle class were 5.06(C.I = 4.81-5.32, p <0.001) and 2.62(C.I = 2.46-2.78, p <0.001) respectively times more likely to IDWS than the poor. This pattern was sustained when other confounding variables were introduced into the regression equation as control. Households headed by women used improved drinking water sources than those headed by men. However, wealth index has strong influence on the strength of relationship between sex of household head and improved drinking water sources.

Age, growth, and mortality of introduced flathead catfish in Atlantic rivers and a review of other populations

USGS Publications Warehouse

Kwak, T.J.; Pine, William E.; Waters, D.S.

2006-01-01

Knowledge of individual growth and mortality rates of an introduced fish population is required to determine the success and degree of establishment as well as to predict the fish's impact on native fauna. The age and growth of flathead catfish Pylodictis olivaris have been studied extensively in the species' native and introduced ranges, and estimates have varied widely. We quantified individual growth rates and age structure of three introduced flathead catfish populations in North Carolina's Atlantic slope rivers using sagittal otoliths, determined trends in growth rates over time, compared these estimates among rivers in native and introduced ranges, and determined total mortality rates for each population. Growth was significantly faster in the Northeast Cape Fear River (NECFR) than in the Lumber and Neuse rivers. Fish in the NECFR grew to a total length of 700 mm by age 7, whereas fish in the Neuse and Lumber river populations reached this length by 8 and 10 years, respectively. The growth rates of fish in all three rivers were consistently higher than those of native riverine populations, similar to those of native reservoir populations, and slower than those of other introduced riverine populations. In general, recent cohorts (1998-2001 year-classes) in these three rivers exhibited slower growth among all ages than did cohorts previous to the 1998 year-class. The annual total mortality rate was similar among the three rivers, ranging from 0.16 to 0.20. These mortality estimates are considerably lower than those from the Missouri and Mississippi rivers, suggesting relatively low fishing mortality for these introduced populations. Overall, flathead catfish populations in reservoirs grow faster than those in rivers, the growth rates of introduced populations exceed those of native populations, and eastern United States populations grow faster than those in western states. Such trends constitute critical information for understanding and managing local populations.

Microsatellite genetic diversity and differentiation of native and introduced grass carp populations in three continents

USGS Publications Warehouse

Chapman, Duane C.; Chen, Qin; Wang, Chenghui; Zhao, Jinlian; Lu, Guoqing; Zsigmond, Jeney; Li, Si-Fa

2012-01-01

Grass carp (Ctenopharyngodon idella), a freshwater species native to China, has been introduced to about 100 countries/regions and poses both biological and environmental challenges to the receiving ecosystems. In this study, we analyzed genetic variation in grass carp from three introduced river systems (Mississippi River Basin in US, Danube River in Hungary, and Tone River in Japan) as well as its native ranges (Yangtze, Pearl, and Amur Rivers) in China using 21 novel microsatellite loci. The allelic richness, observed heterozygosity, and within-population gene diversity were found to be lower in the introduced populations than in the native populations, presumably due to the small founder population size of the former. Significant genetic differentiation was found between all pairwise populations from different rivers. Both principal component analysis and Bayesian clustering analysis revealed obvious genetic distinction between the native and introduced populations. Interestingly, genetic bottlenecks were detected in the Hungarian and Japanese grass carp populations, but not in the North American population, suggesting that the Mississippi River Basin grass carp has experienced rapid population expansion with potential genetic diversification during the half-century since its introduction. Consequently, the combined forces of the founder effect, introduction history, and rapid population expansion help explaining the observed patterns of genetic diversity within and among both native and introduced populations of the grass carp.

Geographic proximity not a prerequisite for invasion: Hawaii not the source of California invasion by light brown apple moth (Epiphyas postvittana).

PubMed

Rubinoff, Daniel; Holland, Brenden S; San Jose, Michael; Powell, Jerry A

2011-01-27

The light brown apple moth (LBAM), Epiphyas postvittana (Walker), is native to Australia but invaded England, New Zealand, and Hawaii more than 100 years ago. In temperate climates, LBAM can be a major agricultural pest. In 2006 LBAM was discovered in California, instigating eradication efforts and quarantine against Hawaiian agriculture, the assumption being that Hawaii was the source of the California infestation. Genetic relationships among populations in Hawaii, California, and New Zealand are crucial to understanding LBAM invasion dynamics across the Pacific. We sequenced mitochondrial DNA (mtDNA) from 1293 LBAM individuals from California (695), Hawaii (448), New Zealand (147), and Australia (3) to examine haplotype diversity and structure among introduced populations, and evaluate the null hypothesis that invasive populations are from a single panmictic source. However, invasive populations in California and New Zealand harbor deep genetic diversity, whereas Hawaii shows low level, shallow diversity. LBAM recently has established itself in California, but was in Hawaii and New Zealand for hundreds of generations, yet California and New Zealand show similar levels of genetic diversity relative to Hawaii. Thus, there is no clear relationship between duration of invasion and genetic structure. Demographic statistics suggest rapid expansion occurring in California and past expansions in New Zealand; multiple introductions of diverse, genetically fragmented lineages could contribute to these patterns. Hawaii and California share no haplotypes, therefore, Hawaii is not the source of the California introduction. Paradoxically, Hawaii and California share multiple haplotypes with New Zealand. New Zealand may be the source for the California and Hawaii infestations, but the introductions were independent, and Hawaii was invaded only once. This has significant implications for quarantine, and suggests that probability of invasion is not directly related to geographic distance. Surprisingly, Hawaiian LBAM populations have much lower genetic diversity than California, despite being older.

Geographic Proximity Not a Prerequisite for Invasion: Hawaii Not the Source of California Invasion by Light Brown Apple Moth (Epiphyas postvittana)

PubMed Central

Rubinoff, Daniel; Holland, Brenden S.; San Jose, Michael; Powell, Jerry A.

2011-01-01

Background The light brown apple moth (LBAM), Epiphyas postvittana (Walker), is native to Australia but invaded England, New Zealand, and Hawaii more than 100 years ago. In temperate climates, LBAM can be a major agricultural pest. In 2006 LBAM was discovered in California, instigating eradication efforts and quarantine against Hawaiian agriculture, the assumption being that Hawaii was the source of the California infestation. Genetic relationships among populations in Hawaii, California, and New Zealand are crucial to understanding LBAM invasion dynamics across the Pacific. Methodology/Principal Findings We sequenced mitochondrial DNA (mtDNA) from 1293 LBAM individuals from California (695), Hawaii (448), New Zealand (147), and Australia (3) to examine haplotype diversity and structure among introduced populations, and evaluate the null hypothesis that invasive populations are from a single panmictic source. However, invasive populations in California and New Zealand harbor deep genetic diversity, whereas Hawaii shows low level, shallow diversity. Conclusions/Significance LBAM recently has established itself in California, but was in Hawaii and New Zealand for hundreds of generations, yet California and New Zealand show similar levels of genetic diversity relative to Hawaii. Thus, there is no clear relationship between duration of invasion and genetic structure. Demographic statistics suggest rapid expansion occurring in California and past expansions in New Zealand; multiple introductions of diverse, genetically fragmented lineages could contribute to these patterns. Hawaii and California share no haplotypes, therefore, Hawaii is not the source of the California introduction. Paradoxically, Hawaii and California share multiple haplotypes with New Zealand. New Zealand may be the source for the California and Hawaii infestations, but the introductions were independent, and Hawaii was invaded only once. This has significant implications for quarantine, and suggests that probability of invasion is not directly related to geographic distance. Surprisingly, Hawaiian LBAM populations have much lower genetic diversity than California, despite being older. PMID:21298019

Origin of Japanese White-Eyes and Brown-Eared Bulbuls on the Volcano Islands.

PubMed

Sugita, Norimasa; Kawakami, Kazuto; Nishiumi, Isao

2016-04-01

The Ogasawara Archipelago comprises two groups of oceanic islands: the Bonin Islands, formed in the Paleogene, and the Volcano Islands, formed in the Quaternary. These groups are located within a moderate distance (ca. 160-270 km) of one another; thus, most land bird species are not distinguished as different subspecies. Two land birds, however, show unusual distribution. The Japanese white-eyes Zosterops japonicus originally inhabited only the Volcano Islands, but has been introduced to the Bonin Islands. The brown-eared bulbuls Hypsipetes amaurotis are distributed as a different subspecies. We investigated their genetic differences and divergences in the Ogasawara Archipelago using mitochondria DNA. The Volcano population of white-eyes had four endemic haplotypes that were divergent from one another, except for the Bonin population, which shared three haplotypes with the Volcano, Izu, and Ryukyu Islands and did not have any endemic haplotype. This is the first genetic suggestion that the Bonin population is a hybrid of introduced populations. With respect to bulbuls, the Volcano and Bonin Islands each had a single endemic haplotype. The Volcano haplotype is closest to a haplotype shared with Izu, the Japanese mainland, Daito and Ryukyu, whereas the Bonin haplotype is closest to one endemic to the south Ryukyu Islands. This indicates that the sources of the two bulbul populations can be geologically and temporally distinguished. The populations of the two species in the Ogasawara Archipelago are irreplaceable, owing to their genetic differences and should be regarded as evolutionarily significant units. In order to prevent introgression between the two populations, we must restrict interisland transfers.

High levels of diversity and population structure in the potato late blight pathogen at the Mexico centre of origin.

PubMed

Wang, Jianan; Fernández-Pavía, Sylvia P; Larsen, Meredith M; Garay-Serrano, Edith; Gregorio-Cipriano, Rosario; Rodríguez-Alvarado, Gerardo; Grünwald, Niklaus J; Goss, Erica M

2017-02-01

Globally destructive crop pathogens often emerge by migrating out of their native ranges. These pathogens are often diverse at their centre of origin and may exhibit adaptive variation in the invaded range via multiple introductions from different source populations. However, source populations are generally unidentified or poorly studied compared to invasive populations. Phytophthora infestans, the causal agent of late blight, is one of the most costly pathogens of potato and tomato worldwide. Mexico is the centre of origin and diversity of P. infestans and migration events out of Mexico have enormously impacted disease dynamics in North America and Europe. The debate over the origin of the pathogen, and population studies of P. infestans in Mexico, has focused on the Toluca Valley, whereas neighbouring regions have been little studied. We examined the population structure of P. infestans across central Mexico, including samples from Michoacán, Tlaxcala and Toluca. We found high levels of diversity consistent with sexual reproduction in Michoacán and Tlaxcala and population subdivision that was strongly associated with geographic region. We determined that population structure in central Mexico has contributed to diversity in introduced populations based on relatedness of U.S. clonal lineages to Mexican isolates from different regions. Our results suggest that P. infestans exists as a metapopulation in central Mexico, and this population structure could be contributing to the repeated re-emergence of P. infestans in the United States and elsewhere. © 2016 John Wiley & Sons Ltd.

Using particle dispersal models to assist in the conservation and recovery of the overexploited native oyster (Ostrea edulis) in an enclosed sea lough

NASA Astrophysics Data System (ADS)

Smyth, David; Kregting, Louise; Elsäßer, Björn; Kennedy, Richard; Roberts, Dai

2016-02-01

Oyster populations around the world have seen catastrophic decline which has been largely attributed to overexploitation, disease and pollution. While considerable effort and resources have been implemented into restoring these important environmental engineers, the success of oyster populations is often limited by poor understanding of site-specific dispersal patterns of propagules. Water-borne transport is a key factor controlling or regulating the dispersal of the larval stage of benthic marine invertebrates which have limited mobility. The distribution of the native oyster Ostrea edulis in Strangford Lough, Northern Ireland, together with their densities and population structure at subtidal and intertidal sites has been documented at irregular intervals between 1997 and 2013. This paper revisits this historical data and considers whether different prevailing environmental conditions can be used to explain the distribution, densities and population structure of O. edulis in Strangford Lough. The approach adopted involved comparing predictive 2D hydrodynamic models coupled with particle tracking to simulate the dispersal of oyster larvae with historical and recent field records of the distribution of both subtidal and intertidal, populations since 1995. Results from the models support the hypothesis that commercial stocks of O. edulis introduced into Strangford Lough in the 1990s resulted in the re-establishment of wild populations of oysters in the Northern Basin which in turn provided a potential source of propagules for subtidal populations. These results highlight that strategic site selection (while inadvertent in the case of the introduced population in 1995) for the re-introduction of important shellfish species can significantly accelerate their recovery and restoration.

Ecology and control of an introduced population of Southern Watersnakes (Nerodia fasciata) in southern California

USGS Publications Warehouse

Reed, Robert; Todd, Brian D; Miano, Oliver J.; Canfield, Mark; Fisher, Robert N.; McMartin, Louanne

2016-01-01

Native to the southeastern United States, Southern Watersnakes (Nerodia fasciata) are known from two sites in California, but their ecological impacts are poorly understood. We investigated the ecology of Southern Watersnakes in Machado Lake, Harbor City, Los Angeles County, California, including an assessment of control opportunities. We captured 306 watersnakes as a result of aquatic trapping and hand captures. We captured snakes of all sizes (162–1063 mm snout–vent length [SVL], 3.5–873.3 g), demonstrating the existence of a well-established population. The smallest reproductive female was 490 mm SVL and females contained 12–46 postovulatory embryos (mean  =  21). Small watersnakes largely consumed introduced Western Mosquitofish (Gambusia affinis), while larger snakes specialized on larval and metamorph American Bullfrogs (Lithobates catesbeianus) and Green Sunfish (Lepomis cyanellus). Overall capture per unit effort (CPUE) in traps declined with time during an intensive 76-d trapping bout, but CPUE trends varied considerably among traplines and it is unlikely that the overall decline in CPUE represented a major decrease in the snake population size. Although we found no direct evidence that Southern Watersnakes are affecting native species in Machado Lake, this population may serve as a source for intentional or unintentional transportation of watersnakes to bodies of water containing imperiled native prey species or potential competitors.

Larvivorous fish for preventing malaria transmission.

PubMed

Walshe, Deirdre P; Garner, Paul; Adeel, Ahmed A; Pyke, Graham H; Burkot, Thomas R

2017-12-11

Adult female Anopheles mosquitoes can transmit Plasmodium parasites that cause malaria. Some fish species eat mosquito larvae and pupae. In disease control policy documents, the World Health Organization (WHO) includes biological control of malaria vectors by stocking ponds, rivers, and water collections near where people live with larvivorous fish to reduce Plasmodium parasite transmission. In the past, the Global Fund has financed larvivorous fish programmes in some countries, and, with increasing efforts in eradication of malaria, policymakers may return to this option. Therefore, we assessed the evidence base for larvivorous fish programmes in malaria control. To evaluate whether introducing larvivorous fish to anopheline larval habitats impacts Plasmodium parasite transmission. We also sought to summarize studies that evaluated whether introducing larvivorous fish influences the density and presence of Anopheles larvae and pupae in water sources. We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE (PubMed); Embase (Ovid); CABS Abstracts; LILACS; and the metaRegister of Controlled Trials (mRCT) up to 6 July 2017. We checked the reference lists of all studies identified by the search. We examined references listed in review articles and previously compiled bibliographies to look for eligible studies. Also we contacted researchers in the field and the authors of studies that met the inclusion criteria for additional information regarding potential studies for inclusion and ongoing studies. This is an update of a Cochrane Review published in 2013. Randomized controlled trials (RCTs) and non-RCTs, including controlled before-and-after studies, controlled time series, and controlled interrupted time series studies from malaria-endemic regions that introduced fish as a larvicide and reported on malaria in the community or the density of the adult anopheline population. In the absence of direct evidence of an effect on transmission, we performed a secondary analysis on studies that evaluated the effect of introducing larvivorous fish on the density or presence of immature anopheline mosquitoes (larvae and pupae forms) in water sources to determine whether this intervention has any potential that may justify further research in the control of malaria vectors. Two review authors independently screened each article by title and abstract, and examined potentially relevant studies for inclusion using an eligibility form. At least two review authors independently extracted data and assessed risk of bias of included studies. If relevant data were unclear or were not reported, we contacted the study authors for clarification. We presented data in tables, and we summarized studies that evaluated the effects of introducing fish on anopheline immature density or presence, or both. We used the GRADE approach to summarize the certainty of the evidence. We also examined whether the included studies reported any possible adverse impact of introducing larvivorous fish on non-target native species. We identified no studies that reported the effects of introducing larvivorous fish on the primary outcomes of this review: malaria infection in nearby communities, entomological inoculation rate, or on adult Anopheles density.For the secondary analysis, we examined the effects of introducing larvivorous fish on the density and presence of anopheline larvae and pupae in community water sources, and found 15 small studies with a follow-up period between 22 days and five years. These studies were undertaken in Sri Lanka (two studies), India (three studies), Ethiopia (one study), Kenya (two studies), Sudan (one study), Grande Comore Island (one study), Korea (two studies), Indonesia (one study), and Tajikistan (two studies). These studies were conducted in a variety of settings, including localized water bodies (such as wells, domestic water containers, fishponds, and pools (seven studies); riverbed pools below dams (two studies)); rice field plots (five studies); and water canals (two studies). All included studies were at high risk of bias. The research was insufficient to determine whether larvivorous fish reduce the density of Anopheles larvae and pupae (12 studies, unpooled data, very low certainty evidence). Some studies with high stocking levels of fish seemed to arrest the increase in immature anopheline populations, or to reduce the number of immature anopheline mosquitoes, compared with controls. However, this finding was not consistent, and in studies that showed a decrease in immature anopheline populations, the effect was not always consistently sustained. In contrast, some studies reported larvivorous fish reduced the number of water sources withAnopheles larvae and pupae (five studies, unpooled data, low certainty evidence).None of the included studies reported effects of larvivorous fish on local native fish populations or other species. We do not know whether introducing larvivorous fish reduces malaria transmission or the density of adult anopheline mosquito populations.In research studies that examined the effects on immature anopheline stages of introducing fish to potential malaria vector larval habitats, high stocking levels of fish may reduce the density or presence of immature anopheline mosquitoes in the short term. We do not know whether this translates into impact on malaria transmission. Our interpretation of the current evidence is that countries should not invest in fish stocking as a stand alone or supplementary larval control measure in any malaria transmission areas outside the context of research using carefully controlled field studies or quasi-experimental designs. Such research should examine the effects on native fish and other non-target species.

Introduced species and their missing parasites

USGS Publications Warehouse

Torchin, Mark E.; Lafferty, Kevin D.; Dobson, Andrew P.; McKenzie, Valerie J.; Kuris, Armand M.

2003-01-01

Damage caused by introduced species results from the high population densities and large body sizes that they attain in their new location. Escape from the effects of natural enemies is a frequent explanation given for the success of introduced species. Because some parasites can reduce host density and decrease body size, an invader that leaves parasites behind and encounters few new parasites can experience a demographic release and become a pest. To test whether introduced species are less parasitized, we have compared the parasites of exotic species in their native and introduced ranges, using 26 host species of molluscs, crustaceans, fishes, birds, mammals, amphibians and reptiles. Here we report that the number of parasite species found in native populations is twice that found in exotic populations. In addition, introduced populations are less heavily parasitized (in terms of percentage infected) than are native populations. Reduced parasitization of introduced species has several causes, including reduced probability of the introduction of parasites with exotic species (or early extinction after host establishment), absence of other required hosts in the new location, and the host-specific limitations of native parasites adapting to new hosts.

Invasion pathway of the Ctenophore Mnemiopsis leidyi in the Mediterranean Sea.

PubMed

Ghabooli, Sara; Shiganova, Tamara A; Briski, Elizabeta; Piraino, Stefano; Fuentes, Veronica; Thibault-Botha, Delphine; Angel, Dror L; Cristescu, Melania E; Macisaac, Hugh J

2013-01-01

Gelatinous zooplankton outbreaks have increased globally owing to a number of human-mediated factors, including food web alterations and species introductions. The invasive ctenophore Mnemiopsis leidyi entered the Black Sea in the early 1980s. The invasion was followed by the Azov, Caspian, Baltic and North Seas, and, most recently, the Mediterranean Sea. Previous studies identified two distinct invasion pathways of M. leidyi from its native range in the western Atlantic Ocean to Eurasia. However, the source of newly established populations in the Mediterranean Sea remains unclear. Here we build upon our previous study and investigate sequence variation in both mitochondrial (Cytochrome c Oxidase subunit I) and nuclear (Internal Transcribed Spacer) markers in M. leidyi, encompassing five native and 11 introduced populations, including four from the Mediterranean Sea. Extant genetic diversity in Mediterranean populations (n = 8, N a = 10) preclude the occurrence of a severe genetic bottleneck or founder effects in the initial colonizing population. Our mitochondrial and nuclear marker surveys revealed two possible pathways of introduction into Mediterranean Sea. In total, 17 haplotypes and 18 alleles were recovered from all surveyed populations. Haplotype and allelic diversity of Mediterranean populations were comparable to populations from which they were likely drawn. The distribution of genetic diversity and pattern of genetic differentiation suggest initial colonization of the Mediterranean from the Black-Azov Seas (pairwise F ST = 0.001-0.028). However, some haplotypes and alleles from the Mediterranean Sea were not detected from the well-sampled Black Sea, although they were found in Gulf of Mexico populations that were also genetically similar to those in the Mediterranean Sea (pairwise F ST = 0.010-0.032), raising the possibility of multiple invasion sources. Multiple introductions from a combination of Black Sea and native region sources could be facilitated by intense local and transcontinental shipping activity, respectively.

Invasion Pathway of the Ctenophore Mnemiopsis leidyi in the Mediterranean Sea

PubMed Central

Ghabooli, Sara; Shiganova, Tamara A.; Briski, Elizabeta; Piraino, Stefano; Fuentes, Veronica; Thibault-Botha, Delphine; Angel, Dror L.; Cristescu, Melania E.; MacIsaac, Hugh J.

2013-01-01

Gelatinous zooplankton outbreaks have increased globally owing to a number of human-mediated factors, including food web alterations and species introductions. The invasive ctenophore Mnemiopsis leidyi entered the Black Sea in the early 1980s. The invasion was followed by the Azov, Caspian, Baltic and North Seas, and, most recently, the Mediterranean Sea. Previous studies identified two distinct invasion pathways of M. leidyi from its native range in the western Atlantic Ocean to Eurasia. However, the source of newly established populations in the Mediterranean Sea remains unclear. Here we build upon our previous study and investigate sequence variation in both mitochondrial (Cytochrome c Oxidase subunit I) and nuclear (Internal Transcribed Spacer) markers in M. leidyi, encompassing five native and 11 introduced populations, including four from the Mediterranean Sea. Extant genetic diversity in Mediterranean populations (n = 8, N a = 10) preclude the occurrence of a severe genetic bottleneck or founder effects in the initial colonizing population. Our mitochondrial and nuclear marker surveys revealed two possible pathways of introduction into Mediterranean Sea. In total, 17 haplotypes and 18 alleles were recovered from all surveyed populations. Haplotype and allelic diversity of Mediterranean populations were comparable to populations from which they were likely drawn. The distribution of genetic diversity and pattern of genetic differentiation suggest initial colonization of the Mediterranean from the Black-Azov Seas (pairwise F ST = 0.001–0.028). However, some haplotypes and alleles from the Mediterranean Sea were not detected from the well-sampled Black Sea, although they were found in Gulf of Mexico populations that were also genetically similar to those in the Mediterranean Sea (pairwise F ST = 0.010–0.032), raising the possibility of multiple invasion sources. Multiple introductions from a combination of Black Sea and native region sources could be facilitated by intense local and transcontinental shipping activity, respectively. PMID:24303030

Genetic origins of the Minoans and Mycenaeans.

PubMed

Lazaridis, Iosif; Mittnik, Alissa; Patterson, Nick; Mallick, Swapan; Rohland, Nadin; Pfrengle, Saskia; Furtwängler, Anja; Peltzer, Alexander; Posth, Cosimo; Vasilakis, Andonis; McGeorge, P J P; Konsolaki-Yannopoulou, Eleni; Korres, George; Martlew, Holley; Michalodimitrakis, Manolis; Özsait, Mehmet; Özsait, Nesrin; Papathanasiou, Anastasia; Richards, Michael; Roodenberg, Songül Alpaslan; Tzedakis, Yannis; Arnott, Robert; Fernandes, Daniel M; Hughey, Jeffery R; Lotakis, Dimitra M; Navas, Patrick A; Maniatis, Yannis; Stamatoyannopoulos, John A; Stewardson, Kristin; Stockhammer, Philipp; Pinhasi, Ron; Reich, David; Krause, Johannes; Stamatoyannopoulos, George

2017-08-10

The origins of the Bronze Age Minoan and Mycenaean cultures have puzzled archaeologists for more than a century. We have assembled genome-wide data from 19 ancient individuals, including Minoans from Crete, Mycenaeans from mainland Greece, and their eastern neighbours from southwestern Anatolia. Here we show that Minoans and Mycenaeans were genetically similar, having at least three-quarters of their ancestry from the first Neolithic farmers of western Anatolia and the Aegean, and most of the remainder from ancient populations related to those of the Caucasus and Iran. However, the Mycenaeans differed from Minoans in deriving additional ancestry from an ultimate source related to the hunter-gatherers of eastern Europe and Siberia, introduced via a proximal source related to the inhabitants of either the Eurasian steppe or Armenia. Modern Greeks resemble the Mycenaeans, but with some additional dilution of the Early Neolithic ancestry. Our results support the idea of continuity but not isolation in the history of populations of the Aegean, before and after the time of its earliest civilizations.

Unifying error structures in commonly used biotracer mixing models.

PubMed

Stock, Brian C; Semmens, Brice X

2016-10-01

Mixing models are statistical tools that use biotracers to probabilistically estimate the contribution of multiple sources to a mixture. These biotracers may include contaminants, fatty acids, or stable isotopes, the latter of which are widely used in trophic ecology to estimate the mixed diet of consumers. Bayesian implementations of mixing models using stable isotopes (e.g., MixSIR, SIAR) are regularly used by ecologists for this purpose, but basic questions remain about when each is most appropriate. In this study, we describe the structural differences between common mixing model error formulations in terms of their assumptions about the predation process. We then introduce a new parameterization that unifies these mixing model error structures, as well as implicitly estimates the rate at which consumers sample from source populations (i.e., consumption rate). Using simulations and previously published mixing model datasets, we demonstrate that the new error parameterization outperforms existing models and provides an estimate of consumption. Our results suggest that the error structure introduced here will improve future mixing model estimates of animal diet. © 2016 by the Ecological Society of America.

Does enemy damage vary across the range of exotic plant species? Evidence from two coastal dune plant species in eastern Australia.

PubMed

Tabassum, Samiya; Leishman, Michelle R

2018-02-01

Release from natural enemies is often cited as a key factor for understanding the success of invasive plant species in novel environments. However, with time invasive species will accumulate native enemies in their invaded range, with factors such as spread distance from the site of introduction, climate and leaf-level traits potentially affecting enemy acquisition rates. However, the influence of such factors is difficult to assess without examining enemy attack across the entire species' range. We tested the significance of factors associated with range expansion (distance from source population and maximum population density), climatic variables (annual temperature and rainfall) and leaf-level traits [specific leaf area (SLA) and foliar nitrogen concentration] in explaining variation in enemy damage across multiple populations of two coastal invasive plants (Gladiolus gueinzii Kunze and Hydrocotyle bonariensis Lam.) along their entire introduced distribution in eastern Australia. We found that for H. bonariensis, amount of foliar damage increased with distance from source population. In contrast, for G. gueinzii, probability and amount of foliar damage decreased with decreasing temperature and increasing rainfall, respectively. Our results show that patterns of enemy attack across species' ranges are complex and cannot be generalised between species or even range edges.

Loci under selection during multiple range expansions of an invasive plant are mostly population specific, but patterns are associated with climate.

PubMed

Zenni, Rafael D; Hoban, Sean M

2015-07-01

Identifying the genes underlying rapid evolutionary changes, describing their function and ascertaining the environmental pressures that determine fitness are the central elements needed for understanding of evolutionary processes and phenotypic changes that improve the fitness of populations. It has been hypothesized that rapid adaptive changes in new environments may contribute to the rapid spread and success of invasive plants and animals. As yet, studies of adaptation during invasion are scarce, as is knowledge of the genes underlying adaptation, especially in multiple replicated invasions. Here, we quantified how genotype frequencies change during invasions, resulting in rapid evolution of naturalized populations. We used six fully replicated common garden experiments in Brazil where Pinus taeda (loblolly pine) was introduced at the same time, in the same numbers, from the same seed sources, and has formed naturalized populations expanding outward from the plantations. We used a combination of nonparametric, population genetics and multivariate statistics to detect changes in genotype frequencies along each of the six naturalization gradients and their association with climate as well as shifts in allele frequencies compared to the source populations. Results show 25 genes with significant shifts in genotype frequencies. Six genes had shifts in more than one population. Climate explained 25% of the variation in the groups of genes under selection across all locations, but specific genes under strong selection during invasions did not show climate-related convergence. In conclusion, we detected rapid evolutionary changes during invasive range expansions, but the particular gene-level patterns of evolution may be population specific. © 2015 John Wiley & Sons Ltd.

Snake (Colubridae: Thamnophis) predatory responses to chemical cues from native and introduced prey species

USGS Publications Warehouse

Mullin, S.J.; Imbert, H.; Fish, J.M.; Ervin, E.L.; Fisher, R.N.

2004-01-01

Several aquatic vertebrates have been introduced into freshwater systems in California over the past 100 years. Some populations of the two-striped garter snake (Thamnophis hammondii) have lived in sympatry with these species since their introduction; other populations have never encountered them. To assess the possible adaptation to a novel prey, we tested the predatory responses of T. hammondii from different populations to different chemosensory cues from native and introduced prey species. We presented chemical extracts from potential prey types and 2 control odors to individual snakes on cotton swabs and recorded the number of tongue flicks and attacks directed at each swab. Subject response was higher for prey odors than control substances. Odors from introduced centrarchid fish (Lepomis) elicited higher response levels than other prey types, including native anuran larvae (Pseudacris regilla). The pattern of response was similar for both populations of snakes (experienced and nai??ve, with respect to the introduced prey). We suggest that the generalist aquatic lifestyle of T. hammondii has allowed it to take advantage of increasing populations of introduced prey. Decisions on the management strategies for some of these introduced prey species should include consideration of how T. hammondii populations might respond in areas of sympatry.

sourceR: Classification and source attribution of infectious agents among heterogeneous populations

PubMed Central

French, Nigel

2017-01-01

Zoonotic diseases are a major cause of morbidity, and productivity losses in both human and animal populations. Identifying the source of food-borne zoonoses (e.g. an animal reservoir or food product) is crucial for the identification and prioritisation of food safety interventions. For many zoonotic diseases it is difficult to attribute human cases to sources of infection because there is little epidemiological information on the cases. However, microbial strain typing allows zoonotic pathogens to be categorised, and the relative frequencies of the strain types among the sources and in human cases allows inference on the likely source of each infection. We introduce sourceR, an R package for quantitative source attribution, aimed at food-borne diseases. It implements a Bayesian model using strain-typed surveillance data from both human cases and source samples, capable of identifying important sources of infection. The model measures the force of infection from each source, allowing for varying survivability, pathogenicity and virulence of pathogen strains, and varying abilities of the sources to act as vehicles of infection. A Bayesian non-parametric (Dirichlet process) approach is used to cluster pathogen strain types by epidemiological behaviour, avoiding model overfitting and allowing detection of strain types associated with potentially high “virulence”. sourceR is demonstrated using Campylobacter jejuni isolate data collected in New Zealand between 2005 and 2008. Chicken from a particular poultry supplier was identified as the major source of campylobacteriosis, which is qualitatively similar to results of previous studies using the same dataset. Additionally, the software identifies a cluster of 9 multilocus sequence types with abnormally high ‘virulence’ in humans. sourceR enables straightforward attribution of cases of zoonotic infection to putative sources of infection. As sourceR develops, we intend it to become an important and flexible resource for food-borne disease attribution studies. PMID:28558033

Ionospheric Outflow in the Magnetosphere: Circulation and Consequences

NASA Astrophysics Data System (ADS)

Welling, D. T.; Liemohn, M. W.

2017-12-01

Including ionospheric outflow in global magnetohydrodynamic models of near-Earth outer space has become an important step towards understanding the role of this plasma source in the magnetosphere. Such simulations have revealed the importance of outflow in populating the plasma sheet and inner magnetosphere as a function of outflow source characteristics. More importantly, these experiments have shown how outflow can control global dynamics, including tail dynamics and dayside reconnection rate. The broad impact of light and heavy ion outflow can create non-linear feedback loops between outflow and the magnetosphere. This paper reviews some of the most important revelations from global magnetospheric modeling that includes ionospheric outflow of light and heavy ions. It also introduces new advances in outflow modeling and coupling outflow to the magnetosphere.

Performance comparison of single axis tracking and 40° solar panels for sunny weather

NASA Astrophysics Data System (ADS)

Chua, Yaw Long; Yong, Yoon Kuang; Koh, Yit Yan

2017-09-01

The rapid increment in human population and economy growth had led to the rise of the energy demand globally. With the rapid diminishing fossil fuels based energy sources, renewable energy sources had been introduced due to its unlimited availability especially solar energy which is a sustainable and reliable energy. This research was conducted to study and compare the efficiency of the single axis tracking solar panel with a 40° inclined angle solar panel in sunny weather condition. The results indicated that the output generated by the solar panel was directly affected by the angle which the solar panel facing the sun. In terms of performance the single axis tracking solar panel emerged to be more efficient with greater energy generated.

When population genetics meets biological control of the invasive swallow-worts (Vincetoxicum nigrum (L.) Moench and V. rossicum (Kleopow) Barbar)

USDA-ARS?s Scientific Manuscript database

We explored the population genetics of two European swallow-worts belonging to the Apocynaceae that have become established in the eastern United States and Canada. Population genetic data concerning both native and introduced populations are being used to pinpoint introduced population origin, and ...

A genomic view of the peopling of the Americas

PubMed Central

Skoglund, Pontus; Reich, David

2016-01-01

Whole-genome studies have documented that most Native American ancestry stems from a single population that diversified within the continent more than twelve thousand years ago. However, this shared ancestry hides a more complex history whereby at least four distinct streams of Eurasian migration have contributed to present-day and prehistoric Native American populations. Whole genome studies enhanced by technological breakthroughs in ancient DNA now provide evidence of a sequence of events involving initial migrations from a structured Northeast Asian source population with differential relatedness to present-day Australasian populations, followed by a divergence into northern and southern Native American lineages. During the Holocene, new migrations from Asia introduced the Saqqaq/Dorset Paleoeskimo population to the North American Arctic ~4,500 years ago, ancestry that is potentially connected with ancestry found in Athabaskan-speakers today. This was then followed by a major new population turnover in the high Arctic involving Thule-related peoples who are the ancestors of present-day Inuit. We highlight several open questions that could be addressed through future genomic research. PMID:27507099

A genomic view of the peopling of the Americas.

PubMed

Skoglund, Pontus; Reich, David

2016-12-01

Whole-genome studies have documented that most Native American ancestry stems from a single population that diversified within the continent more than twelve thousand years ago. However, this shared ancestry hides a more complex history whereby at least four distinct streams of Eurasian migration have contributed to present-day and prehistoric Native American populations. Whole genome studies enhanced by technological breakthroughs in ancient DNA now provide evidence of a sequence of events involving initial migrations from a structured Northeast Asian source population with differential relatedness to present-day Australasian populations, followed by a divergence into northern and southern Native American lineages. During the Holocene, new migrations from Asia introduced the Saqqaq/Dorset Paleoeskimo population to the North American Arctic ∼4500 years ago, ancestry that is potentially connected with ancestry found in Athabaskan-speakers today. This was then followed by a major new population turnover in the high Arctic involving Thule-related peoples who are the ancestors of present-day Inuit. We highlight several open questions that could be addressed through future genomic research. Copyright © 2016 Elsevier Ltd. All rights reserved.

History and status of introduced mammals and impacts to breeding seabirds on the California channel and Northwestern Baja California Islands

USGS Publications Warehouse

McChesney, G.J.; Tershy, B.R.

1998-01-01

The California Channel Islands, U.S.A., and Northwestern Baja California Islands, Mexico, host important breeding populations of several seabird species, including the endemic Black-vented Shearwater (Puffinus opisthomelas) and Xantus' Murrelet (Synthliboramphus hypoleucus). Mammals introduced to nearly all of the islands beginning in the late 1800s to early 1900s include: cats (Felis catus), dogs (Canis familiaris), Black Rats (Rattus rattus), rabbits and hares (Leporidae), goats (Capra hirca), sheep (Ovis ones), and other grazers. Cats, dogs and rats are seabird predators, grazers such as goats and sheep cause habitat degredation, and rabbits destroy habitat and compete with hole-nesting seabirds. Cats, which were introduced to at least 19 islands and currently occur on ten islands, have had the greatest impacts on seabirds, including the extinction of the endemic Guadalupe Storm-Petrel (Oceanodroma macrodactyla). Cats are known to have eliminated or severely reduced colonies of Black-vented Shearwaters, Cassin's Auklets (Ptychoramphus aleuticus) and Xantus' Murrelets. Black Rats have occurred on a minimum of seven islands and have reduced numbers of small, hole-nesting alcids on at least one island. At many islands, defoliation and erosion caused by rabbits and large grazing mammals has been severe. Their effects on seabirds are not well documented but potentially are serious. Impacts from introduced mammals have been most severe on islands with no native mammalian predators. On the Northwestern Baja California Islands, temporary and permanent human settlements have led to a greater diversity and source of introductions. Programs to remove introduced mammals and to reduce the possibility of future introductions are needed to restore seabird populations and to preserve the biodiversity of the region. Surveys are needed particularly on the Northwestern Baja California Islands to update the status and distribution of seabirds and to further assess impacts from introduced mammals.

Spatial variability and macro‐scale drivers of growth for native and introduced Flathead Catfish populations

USGS Publications Warehouse

Massie, Danielle L.; Smith, Geoffrey; Bonvechio, Timothy F.; Bunch, Aaron J.; Lucchesi, David O.; Wagner, Tyler

2018-01-01

Quantifying spatial variability in fish growth and identifying large‐scale drivers of growth are fundamental to many conservation and management decisions. Although fish growth studies often focus on a single population, it is becoming increasingly clear that large‐scale studies are likely needed for addressing transboundary management needs. This is particularly true for species with high recreational value and for those with negative ecological consequences when introduced outside of their native range, such as the Flathead Catfish Pylodictis olivaris. This study quantified growth variability of the Flathead Catfish across a large portion of its contemporary range to determine whether growth differences existed between habitat types (i.e., reservoirs and rivers) and between native and introduced populations. Additionally, we investigated whether growth parameters varied as a function of latitude and time since introduction (for introduced populations). Length‐at‐age data from 26 populations across 11 states in the USA were modeled using a Bayesian hierarchical von Bertalanffy growth model. Population‐specific growth trajectories revealed large variation in Flathead Catfish growth and relatively high uncertainty in growth parameters for some populations. Relatively high uncertainty was also evident when comparing populations and when quantifying large‐scale patterns. Growth parameters (Brody growth coefficient [K] and theoretical maximum average length [L∞]) were not different (based on overlapping 90% credible intervals) between habitat types or between native and introduced populations. For populations within the introduced range of Flathead Catfish, latitude was negatively correlated with K. For native populations, we estimated an 85% probability that L∞ estimates were negatively correlated with latitude. Contrary to predictions, time since introduction was not correlated with growth parameters in introduced populations of Flathead Catfish. Results of this study suggest that Flathead Catfish growth patterns are likely shaped more strongly by finer‐scale processes (e.g., exploitation or prey abundances) as opposed to macro‐scale drivers.

The devil is in the details: genetic variation in introduced populations and its contributions to invasion.

PubMed

Dlugosch, Katrina M; Anderson, Samantha R; Braasch, Joseph; Cang, F Alice; Gillette, Heather D

2015-05-01

The influence of genetic variation on invasion success has captivated researchers since the start of the field of invasion genetics 50 years ago. We review the history of work on this question and conclude that genetic variation-as surveyed with molecular markers-appears to shape invasion rarely. Instead, there is a significant disconnect between marker assays and ecologically relevant genetic variation in introductions. We argue that the potential for adaptation to facilitate invasion will be shaped by the details of genotypes affecting phenotypes, and we highlight three areas in which we see opportunities to make powerful new insights. (i) The genetic architecture of adaptive variation. Traits shaped by large-effect alleles may be strongly impacted by founder events yet more likely to respond to selection when genetic drift is strong. Large-effect loci may be especially relevant for traits involved in biotic interactions. (ii) Cryptic genetic variation exposed during invasion. Introductions have strong potential to uncover masked variation due to alterations in genetic and ecological environments. (iii) Genetic interactions during admixture of multiple source populations. As divergence among sources increases, positive followed by increasingly negative effects of admixture should be expected. Although generally hypothesized to be beneficial during invasion, admixture is most often reported among sources of intermediate divergence, supporting the possibility that incompatibilities among divergent source populations might be limiting their introgression. Finally, we note that these details of invasion genetics can be coupled with comparative demographic analyses to link genetic changes to the evolution of invasiveness itself. © 2015 John Wiley & Sons Ltd.

Pleistocene to historic shifts in bald eagle diets on the Channel Islands, California.

PubMed

Newsome, Seth D; Collins, Paul W; Rick, Torben C; Guthrie, Daniel A; Erlandson, Jon M; Fogel, Marilyn L

2010-05-18

Studies of current interactions among species, their prey, and environmental factors are essential for mitigating immediate threats to population viability, but the true range of behavioral and ecological flexibility can be determined only through research on deeper timescales. Ecological data spanning centuries to millennia provide important contextual information for long-term management strategies, especially for species that now are living in relict populations. Here we use a variety of methods to reconstruct bald eagle diets and local abundance of their potential prey on the Channel Islands from the late Pleistocene to the time when the last breeding pairs disappeared from the islands in the mid-20th century. Faunal and isotopic analysis of bald eagles shows that seabirds were important prey for immature/adult eagles for millennia before the eagles' local extirpation. In historic times (A.D. 1850-1950), however, isotopic and faunal data show that breeding bald eagles provisioned their chicks with introduced ungulates (e.g., sheep), which were locally present in high densities. Today, bald eagles are the focus of an extensive conservation program designed to restore a stable breeding population to the Channel Islands, but native and nonnative prey sources that were important for bald eagles in the past are either diminished (e.g., seabirds) or have been eradicated (e.g., introduced ungulates). In the absence of sufficient resources, a growing bald eagle population on the Channel Islands could expand its prey base to include carrion from local pinniped colonies, exert predation pressure on a recovering seabird population, and possibly prey on endangered island foxes.

Colony social structure in native and invasive populations of the social wasp Vespula pensylvanica

USGS Publications Warehouse

Hanna, Cause; Cook, Erin D.; Thompson, Ariel R.; Dare, Lyndzey E.; Palaski, Amanda L.; Foote, David; Goodisman, Michael A. D.

2014-01-01

Social insects rank among the most invasive of terrestrial species. The success of invasive social insects stems, in part, from the flexibility derived from their social behaviors. We used genetic markers to investigate if the social system of the invasive wasp, Vespula pensylvanica, differed in its introduced and native habitats in order to better understand variation in social phenotype in invasive social species. We found that (1) nestmate workers showed lower levels of relatedness in introduced populations than native populations, (2) introduced colonies contained workers produced by multiple queens whereas native colonies contained workers produced by only a single queen, (3) queen mate number did not differ significantly between introduced and native colonies, and (4) workers from introduced colonies were frequently produced by queens that originated from foreign nests. Thus, overall, native and introduced colonies differed substantially in social phenotype because introduced colonies more frequently contained workers produced by multiple, foreign queens. In addition, the similarity in levels of genetic variation in introduced and native habitats, as well as observed variation in colony social phenotype in native populations, suggest that colony structure in invasive populations may be partially associated with social plasticity. Overall, the differences in social structure observed in invasive V. pensylvanica parallel those in other, distantly related invasive social insects, suggesting that insect societies often develop similar social phenotypes upon introduction into new habitats.

Lack of adaptation from standing genetic variation despite the presence of putatively adaptive alleles in introduced sweet vernal grass (Anthoxanthum odoratum).

PubMed

Gould, B; Geber, M

2016-01-01

Population genetic theory predicts that the availability of appropriate standing genetic variation should facilitate rapid evolution when species are introduced to new environments. However, few tests of rapid evolution have been paired with empirical surveys for the presence of previously identified adaptive genetic variants in natural populations. In this study, we examined local adaptation to soil Al toxicity in the introduced range of sweet vernal grass (Anthoxanthum odoratum), and we genotyped populations for the presence of Al tolerance alleles previously identified at the long-term ecological Park Grass Experiment (PGE, Harpenden, UK) in the species native range. We found that markers associated with Al tolerance at the PGE were present at appreciable frequency in introduced populations. Despite this, there was no strong evidence of local adaptation to soil Al toxicity among populations. Populations demonstrated significantly different intrinsic root growth rates in the absence of Al. This suggests that selection on correlated root growth traits may constrain the ability of populations to evolve significantly different root growth responses to Al. Our results demonstrate that genotype-phenotype associations may differ substantially between the native and introduced parts of a species range and that adaptive alleles from a native species range may not necessarily promote phenotypic differentiation in the introduced range. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Low Predictability of Colour Polymorphism in Introduced Guppy (Poecilia reticulata) Populations in Panama

PubMed Central

Martínez, Celestino; Chavarría, Carmen; Sharpe, Diana M. T.; De León, Luis Fernando

2016-01-01

Colour polymorphism is a recurrent feature of natural populations, and its maintenance has been studied in a range of taxa in their native ranges. However, less is known about whether (and how) colour polymorphism is maintained when populations are removed from their native environments, as in the case of introduced species. We here address this issue by analyzing variation in colour patterns in recently-discovered introduced populations of the guppy (Poecilia reticulata) in Panama. Specifically, we use classic colour analysis to estimate variation in the number and the relative area of different colour spots across low predation sites in the introduced Panamanian range of the species. We then compare this variation to that found in the native range of the species under low- and high predation regimes. We found aspects of the colour pattern that were both consistent and inconsistent with the classical paradigm of colour evolution in guppies. On one hand, the same colours that dominated in native populations (orange, iridescent and black) were also the most dominant in the introduced populations in Panama. On the other, there were no clear differences between either introduced-low and native low- and high predation populations. Our results are therefore only partially consistent with the traditional role of female preference in the absence of predators, and suggest that additional factors could influence colour patterns when populations are removed from their native environments. Future research on the interaction between female preference and environmental variability (e.g. multifarious selection), could help understand adaptive variation in this widely-introduced species, and the contexts under which variation in adaptive traits parallels (or not) variation in the native range. PMID:26863538

Low Predictability of Colour Polymorphism in Introduced Guppy (Poecilia reticulata) Populations in Panama.

PubMed

Martínez, Celestino; Chavarría, Carmen; Sharpe, Diana M T; De León, Luis Fernando

2016-01-01

Colour polymorphism is a recurrent feature of natural populations, and its maintenance has been studied in a range of taxa in their native ranges. However, less is known about whether (and how) colour polymorphism is maintained when populations are removed from their native environments, as in the case of introduced species. We here address this issue by analyzing variation in colour patterns in recently-discovered introduced populations of the guppy (Poecilia reticulata) in Panama. Specifically, we use classic colour analysis to estimate variation in the number and the relative area of different colour spots across low predation sites in the introduced Panamanian range of the species. We then compare this variation to that found in the native range of the species under low- and high predation regimes. We found aspects of the colour pattern that were both consistent and inconsistent with the classical paradigm of colour evolution in guppies. On one hand, the same colours that dominated in native populations (orange, iridescent and black) were also the most dominant in the introduced populations in Panama. On the other, there were no clear differences between either introduced-low and native low- and high predation populations. Our results are therefore only partially consistent with the traditional role of female preference in the absence of predators, and suggest that additional factors could influence colour patterns when populations are removed from their native environments. Future research on the interaction between female preference and environmental variability (e.g. multifarious selection), could help understand adaptive variation in this widely-introduced species, and the contexts under which variation in adaptive traits parallels (or not) variation in the native range.

Economic and fiscal implications of aging for subnational American governments.

PubMed

Serow, W J

2001-01-01

This article begins with a brief review of the extensive literature dealing with the macroeconomic consequences of population aging in industrialized societies and places the question in the context of the political and economic framework of the United States. Next, we move to the fiscal ramifications of population aging for subnational units of government. The varying demographic sources of aging are then introduced and their economic implications are reviewed. The role of population aging within the context of subnational fiscal impacts is first examined by reviewing patterns of change in demand for state-government-provided public goods and services associated with an older population. These include primarily health care and income security. These considerations on the expenditure side are then extended to substate government, where primary and secondary education are easily the largest component of public budgets. Finally, the implications of demographic change on the revenue side of state and local public finances are considered, including potential impacts on sales, property, and income tax receipts.

Habitat Suitability Index Models: Muskrat

USGS Publications Warehouse

Allen, Arthur W.; Hoffman, Robert D.

1984-01-01

The muskrat (Ondatra zibethicus) is the most valuable semi-aquatic furbearer in North America, with a total fur trade income in the millions of dollars (Willner et al. 1980). With the exception of Florida, and coastal Georgia and South Carol ina, native and introduced populations of muskrats occur throughout most of North America. Muskrats are an important component of the marsh ecosystem, serving as a food source for many predators (Wilson 1968), and can have a major impact on wetland vegetation (O'Neil 1949; Errington 1961, 1963; Weller and Spatcher 1965).

Invasion genetics of the Bermuda buttercup (Oxalis pes-caprae): complex intercontinental patterns of genetic diversity, polyploidy and heterostyly characterize both native and introduced populations.

PubMed

Ferrero, Victoria; Barrett, Spencer C H; Castro, Sílvia; Caldeirinha, Patrícia; Navarro, Luis; Loureiro, João; Rodríguez-Echeverría, Susana

2015-05-01

Genetic diversity in populations of invasive species is influenced by a variety of factors including reproductive systems, ploidy level, stochastic forces associated with colonization and multiple introductions followed by admixture. Here, we compare genetic variation in native and introduced populations of the clonal plant Oxalis pes-caprae to investigate the influence of reproductive mode and ploidy on levels of diversity. This species is a tristylous geophyte native to South Africa. Invasive populations throughout much of the introduced range are composed of a sterile clonal pentaploid short-styled form. We examined morph ratios, ploidy level, reproductive mode and genetic diversity at nuclear microsatellite loci in 10 and 12 populations from South Africa and the Western Mediterranean region, respectively. Flow cytometry confirmed earlier reports of diploids and tetraploids in the native range, with a single population containing pentaploid individuals. Introduced populations were composed mainly of pentaploids, but sexual tetraploids were also found. There was clear genetic differentiation between ploidy levels, but sexual populations from both regions were not significantly different in levels of diversity. Invasive populations of the pentaploid exhibited dramatically reduced levels of diversity but were not genetically uniform. The occurrence of mixed ploidy levels and stylar polymorphism in the introduced range is consistent with multiple introductions to the Western Mediterranean. This inference was supported by variation patterns at microsatellite loci. Our study indicates that some invasive populations of Oxalis pes-caprae are not entirely clonal, as often assumed, and multiple introductions and recombination have the potential to increase genetic variation in the introduced range. © 2014 John Wiley & Sons Ltd.

Risk assessment for the reintroduction of anadromous salmonids upstream of Chief Joseph and Grand Coulee Dams, Northeastern Washington

USGS Publications Warehouse

Hardiman, Jill M.; Breyta, Rachel B.; Haskell, Craig A.; Ostberg, Carl O.; Hatten, James R.; Connolly, Patrick J.

2017-09-12

The Upper Columbia United Tribes (UCUT; Spokane, Colville, Kootenai, Coeur d’Alene, and Kalispel Tribes) and Washington Department of Fish and Wildlife want to reintroduce anadromous salmonids to their historical range to restore ecosystem function and lost cultural and spiritual relationships in the upper Columbia River, northeastern Washington. The UCUT contracted with the U.S. Geological Survey to assess risks to resident taxa (existing fish populations in the reintroduction area upstream of Chief Joseph and Grand Coulee Dams) and reintroduced salmon associated with reintroduction. We developed a risk assessment framework for reintroduction of anadromous salmonids upstream of Chief Joseph and Grand Coulee Dams. To accomplish this goal, we applied strategies identified in previous risk assessment frameworks for reintroduction. The risk assessment is an initial step towards an anadromous reintroduction strategy. An initial list of potential donor sources for reintroduction species was developed from previous published sources for Chinook Salmon (Oncorhynchus tshawytscha) donors in the Transboundary Reach of the Columbia River, British Columbia; an ecological risk assessment of upper Columbia River hatchery programs on non-target taxa of concern; and a review of existing hatchery programsDuring two workshops, we further identified and ranked potential donor sources of anadromous Redband Trout (steelhead; O. mykiss), Chinook Salmon, Sockeye Salmon (O. nerka), and Coho Salmon (O. kisutch). We also identified resident fish populations of interest and their primary habitat, location, status, and pathogen concerns to determine the potential risks of reintroduction. Species were deemed of interest based on resource management and potential interactions (that is, genetics, competition, and predation) with introduced species. We developed tables of potential donors by species and characterized potential sources (hatchery and natural origins), populations (individual runs), broodstock management and history, and potential constraints (that is, Endangered Species Act [ESA] listing, Evolutionarily Significant Unit concerns, pathogens, and availability). During the workshops, a group of regional fisheries and topic experts subjectively ranked the relative risks of pathogens, genetic effects, predation, and competition to resident fish and reintroduced salmonids. We assessed the pathogen risk of each potential donor for introducing new pathogens and the increased burden to existing pathogens for resident species upstream of the dams. We considered genetic risks to resident and downstream conspecifics and ecological impacts, including competition for food and space, predator-prey interactions, and ecosystem benefits/impacts. Each reintroduced species donor source was ranked based on abundance/viability (demographic risk to source and feasibility of collection), ancestral/genetic similarity (evolutionary similarity to historical populations), local adaptation (geographic proximity/similarity of source conditions to reintroduction conditions), and life history compatibility (including migration; spawn timing; and relative usage of reservoir, main-stem, or tributary habitats) with environmental conditions in the reintroduction area. We synthesized this information by species for all potential donors, in which an overall score and ranking system was established for decision support in donor selection for reintroduction into the upper Columbia River. We also provided information outside the ranking process by:Identifying predator-prey interactions and competition for food and space among species,Developing a decision support framework for donor selection, andProviding decision support for reintroduction strategies.

Understanding the recent colonization history of a plant pathogenic fungus using population genetic tools and Approximate Bayesian Computation

PubMed Central

Barrès, B; Carlier, J; Seguin, M; Fenouillet, C; Cilas, C; Ravigné, V

2012-01-01

Understanding the processes by which new diseases are introduced in previously healthy areas is of major interest in elaborating prevention and management policies, as well as in understanding the dynamics of pathogen diversity at large spatial scale. In this study, we aimed to decipher the dispersal processes that have led to the emergence of the plant pathogenic fungus Microcyclus ulei, which is responsible for the South American Leaf Blight (SALB). This fungus has devastated rubber tree plantations across Latin America since the beginning of the twentieth century. As only imprecise historical information is available, the study of population evolutionary history based on population genetics appeared most appropriate. The distribution of genetic diversity in a continental sampling of four countries (Brazil, Ecuador, Guatemala and French Guiana) was studied using a set of 16 microsatellite markers developed specifically for this purpose. A very strong genetic structure was found (Fst=0.70), demonstrating that there has been no regular gene flow between Latin American M. ulei populations. Strong bottlenecks probably occurred at the foundation of each population. The most likely scenario of colonization identified by the Approximate Bayesian Computation (ABC) method implemented in 𝒟ℐ𝒴𝒜ℬ𝒞 suggested two independent sources from the Amazonian endemic area. The Brazilian, Ecuadorian and Guatemalan populations might stem from serial introductions through human-mediated movement of infected plant material from an unsampled source population, whereas the French Guiana population seems to have arisen from an independent colonization event through spore dispersal. PMID:22828899

Intraspecific geographic variation of fragrances acquired by orchid bees in native and introduced populations.

PubMed

Ramírez, Santiago R; Eltz, Thomas; Fritzsch, Falko; Pemberton, Robert; Pringle, Elizabeth G; Tsutsui, Neil D

2010-08-01

Male orchid bees collect volatiles, from both floral and non-floral sources, that they expose as pheromone analogues (perfumes) during courtship display. The chemical profile of these perfumes, which includes terpenes and aromatic compounds, is both species-specific and divergent among closely related lineages. Thus, fragrance composition is thought to play an important role in prezygotic reproductive isolation in euglossine bees. However, because orchid bees acquire fragrances entirely from exogenous sources, the chemical composition of male perfumes is prone to variation due to environmental heterogeneity across habitats. We used Gas Chromatography/Mass Spectrometry (GC/MS) to characterize the perfumes of 114 individuals of the green orchid bee (Euglossa aff. viridissima) sampled from five native populations in Mesoamerica and two naturalized populations in the southeastern United States. We recorded a total of 292 fragrance compounds from hind-leg extracts, and found that overall perfume composition was different for each population. We detected a pronounced chemical dissimilarity between native (Mesoamerica) and naturalized (U.S.) populations that was driven both by proportional differences of common compounds as well as the presence of a few chemicals unique to each population group. Despite these differences, our data also revealed remarkable qualitative consistency in the presence of several major fragrance compounds across distant populations from dissimilar habitats. In addition, we demonstrate that naturalized bees are attracted to and collect large quantities of triclopyr 2-butoxyethyl ester, the active ingredient of several commercially available herbicides. By comparing incidence values and consistency indices across populations, we identify putative functional compounds that may play an important role in courtship signaling in this species of orchid bee.

Intraspecific Geographic Variation of Fragrances Acquired by Orchid Bees in Native and Introduced Populations

PubMed Central

Eltz, Thomas; Fritzsch, Falko; Pemberton, Robert; Pringle, Elizabeth G.; Tsutsui, Neil D.

2010-01-01

Male orchid bees collect volatiles, from both floral and non-floral sources, that they expose as pheromone analogues (perfumes) during courtship display. The chemical profile of these perfumes, which includes terpenes and aromatic compounds, is both species-specific and divergent among closely related lineages. Thus, fragrance composition is thought to play an important role in prezygotic reproductive isolation in euglossine bees. However, because orchid bees acquire fragrances entirely from exogenous sources, the chemical composition of male perfumes is prone to variation due to environmental heterogeneity across habitats. We used Gas Chromatography/Mass Spectrometry (GC/MS) to characterize the perfumes of 114 individuals of the green orchid bee (Euglossa aff. viridissima) sampled from five native populations in Mesoamerica and two naturalized populations in the southeastern United States. We recorded a total of 292 fragrance compounds from hind-leg extracts, and found that overall perfume composition was different for each population. We detected a pronounced chemical dissimilarity between native (Mesoamerica) and naturalized (U.S.) populations that was driven both by proportional differences of common compounds as well as the presence of a few chemicals unique to each population group. Despite these differences, our data also revealed remarkable qualitative consistency in the presence of several major fragrance compounds across distant populations from dissimilar habitats. In addition, we demonstrate that naturalized bees are attracted to and collect large quantities of triclopyr 2-butoxyethyl ester, the active ingredient of several commercially available herbicides. By comparing incidence values and consistency indices across populations, we identify putative functional compounds that may play an important role in courtship signaling in this species of orchid bee. Electronic supplementary material The online version of this article (doi:10.1007/s10886-010-9821-3) contains supplementary material, which is available to authorized users. PMID:20623328

A new catalogue of ultraluminous X-ray sources (and more!)

NASA Astrophysics Data System (ADS)

Roberts, T.; Earnshaw, H.; Walton, D.; Middleton, M.; Mateos, S.

2017-10-01

Many of the critical issues of ultraluminous X-ray source (ULX) science - for example the prevalence of IMBH and/or ULX pulsar candidates within the wider ULX population - can only be addressed by studying statistical samples of ULXs. Similarly, characterising the range of properties displayed by ULXs, and so understanding their accretion physics, requires large samples of objects. To this end, we introduce a new catalogue of 376 ultraluminous X-ray sources and 1092 less luminous point X-ray sources associated with nearby galaxies, derived from the 3XMM-DR4 catalogue. We highlight applications of this catalogue, for example the identification of new IMBH candidates from the most luminous ULXs; and examining the physics of objects at the Eddington threshold, where their luminosities of ˜ 10^{39} erg s^{-1} indicate their accretion rates are ˜ Eddington. We also show how the catalogue can be used to start to examine a wider range of lower luminosity (sub-ULX) point sources in star forming galaxies than previously accessible through spectral stacking, and argue why this is important for galaxy formation in the high redshift Universe.

Feral Cat Globetrotters: genetic traces of historical human-mediated dispersal.

PubMed

Koch, Katrin; Algar, Dave; Schwenk, Klaus

2016-08-01

Endemic species on islands are highly susceptible to local extinction, in particular if they are exposed to invasive species. Invasive predators, such as feral cats, have been introduced to islands around the world, causing major losses in local biodiversity. In order to control and manage invasive species successfully, information about source populations and level of gene flow is essential. Here, we investigate the origin of feral cats of Hawaiian and Australian islands to verify their European ancestry and a potential pattern of isolation by distance. We analyzed the genetic structure and diversity of feral cats from eleven islands as well as samples from Malaysia and Europe using mitochondrial DNA (ND5 and ND6 regions) and microsatellite DNA data. Our results suggest an overall European origin of Hawaiian cats with no pattern of isolation by distance between Australian, Malaysian, and Hawaiian populations. Instead, we found low levels of genetic differentiation between samples from Tasman Island, Lana'i, Kaho'olawe, Cocos (Keeling) Island, and Asia. As these populations are separated by up to 10,000 kilometers, we assume an extensive passive dispersal event along global maritime trade routes in the beginning of the 19th century, connecting Australian, Asian, and Hawaiian islands. Thus, islands populations, which are characterized by low levels of current gene flow, represent valuable sources of information on historical, human-mediated global dispersal patterns of feral cats.

Genetic concepts and uncertainties in restoring fish populations and species

USGS Publications Warehouse

Reisenbichler, R.R.; Utter, F.M.; Krueger, C.C.

2003-01-01

Genetic considerations can be crucially important to the success of reintroductions of lotic species. Current paradigms for conservation and population genetics provide guidance for reducing uncertainties in genetic issues and for increasing the likelihood of achieving restoration. Effective restoration is facilitated through specific goals and objectives developed from the definition that a restored or healthy population is (i) genetically adapted to the local environment, (ii) self-sustaining at abundances consistent with the carrying capacity of the river system, (iii) genetically compatible with neighboring populations so that substantial outbreeding depression does not result from straying and interbreeding between populations, and (iv) sufficiently diverse genetically to accommodate environmental variability over many decades. Genetic principles reveal the importance of describing and adhering to the ancestral lineages for the species to be restored and enabling genetic processes to maintain diversity and fitness in the populations under restoration. Newly established populations should be protected from unnecessary human sources of mortality, gene flow from maladapted (e.g., hatchery) or exotic populations, and inadvertent selection by fisheries or other human activities. Such protection facilitates initial, rapid adaptation of the population to its environment and should enhance the chances for persistence. Various uncertainties about specific restoration actions must be addressed on a case-by-case basis. Such uncertainties include whether to allow natural colonization or to introduce fish, which populations are suitable as sources for reintroduction, appropriate levels of gene flow from other populations, appropriate levels of artificial production, appropriate minimum numbers of individuals released or maintained in the population, and the best developmental stages for releasing fish into the restored stream. Rigorous evaluation or experimental management is necessary to reduce uncertainty in our knowledge so that future conservation and restoration activities can be more effective.

Automated deconvolution of structured mixtures from heterogeneous tumor genomic data

PubMed Central

Roman, Theodore; Xie, Lu

2017-01-01

With increasing appreciation for the extent and importance of intratumor heterogeneity, much attention in cancer research has focused on profiling heterogeneity on a single patient level. Although true single-cell genomic technologies are rapidly improving, they remain too noisy and costly at present for population-level studies. Bulk sequencing remains the standard for population-scale tumor genomics, creating a need for computational tools to separate contributions of multiple tumor clones and assorted stromal and infiltrating cell populations to pooled genomic data. All such methods are limited to coarse approximations of only a few cell subpopulations, however. In prior work, we demonstrated the feasibility of improving cell type deconvolution by taking advantage of substructure in genomic mixtures via a strategy called simplicial complex unmixing. We improve on past work by introducing enhancements to automate learning of substructured genomic mixtures, with specific emphasis on genome-wide copy number variation (CNV) data, as well as the ability to process quantitative RNA expression data, and heterogeneous combinations of RNA and CNV data. We introduce methods for dimensionality estimation to better decompose mixture model substructure; fuzzy clustering to better identify substructure in sparse, noisy data; and automated model inference methods for other key model parameters. We further demonstrate their effectiveness in identifying mixture substructure in true breast cancer CNV data from the Cancer Genome Atlas (TCGA). Source code is available at https://github.com/tedroman/WSCUnmix PMID:29059177

The biology of small, introduced populations, with special reference to biological control

PubMed Central

Fauvergue, Xavier; Vercken, Elodie; Malausa, Thibaut; Hufbauer, Ruth A

2012-01-01

Populations are introduced into novel environments in different contexts, one being the biological control of pests. Despite intense efforts, less than half introduced biological control agents establish. Among the possible approaches to improve biological control, one is to better understand the processes that underpin introductions and contribute to ecological and evolutionary success. In this perspective, we first review the demographic and genetic processes at play in small populations, be they stochastic or deterministic. We discuss the theoretical outcomes of these different processes with respect to individual fitness, population growth rate, and establishment probability. Predicted outcomes differ subtly in some cases, but enough so that the evaluating results of introductions have the potential to reveal which processes play important roles in introduced populations. Second, we attempt to link the theory we have discussed with empirical data from biological control introductions. A main result is that there are few available data, but we nonetheless report on an increasing number of well-designed, theory-driven, experimental approaches. Combining demography and genetics from both theoretical and empirical perspectives highlights novel and exciting avenues for research on the biology of small, introduced populations, and great potential for improving both our understanding and practice of biological control. PMID:22949919

Genetic and Morphometric Divergence of an Invasive Bird: The Introduced House Sparrow (Passer domesticus) in Brazil

PubMed Central

Lima, Marcos R.; Macedo, Regina H. F.; Martins, Thaís L. F.; Schrey, Aaron W.; Martin, Lynn B.; Bensch, Staffan

2012-01-01

Introduced species are interesting systems for the study of contemporary evolution in new environments because of their spatial and temporal scales. For this study we had three aims: (i) to determine how genetic diversity and genetic differentiation of introduced populations of the house sparrow (Passer domesticus) in Brazil varies with range expansion, (ii) to determine how genetic diversity and differentiation in Brazil compares to ancestral European populations; and (iii) to determine whether selection or genetic drift has been more influential on phenotypic divergence. We used six microsatellite markers to genotype six populations from Brazil and four populations from Europe. We found slightly reduced levels of genetic diversity in Brazilian compared to native European populations. However, among introduced populations of Brazil, we found no association between genetic diversity and time since introduction. Moreover, overall genetic differentiation among introduced populations was low indicating that the expansion took place from large populations in which genetic drift effects would likely have been weak. We found significant phenotypic divergence among sites in Brazil. Given the absence of a spatial genetic pattern, divergent selection and not genetic drift seems to be the main force behind most of the phenotypic divergence encountered. Unravelling whether microevolution (e.g., allele frequency change), phenotypic plasticity, or both mediated phenotypic divergence is challenging and will require experimental work (e.g., common garden experiments or breeding programs). PMID:23285283

Efficient population-scale variant analysis and prioritization with VAPr.

PubMed

Birmingham, Amanda; Mark, Adam M; Mazzaferro, Carlo; Xu, Guorong; Fisch, Kathleen M

2018-04-06

With the growing availability of population-scale whole-exome and whole-genome sequencing, demand for reproducible, scalable variant analysis has spread within genomic research communities. To address this need, we introduce the Python package VAPr (Variant Analysis and Prioritization). VAPr leverages existing annotation tools ANNOVAR and MyVariant.info with MongoDB-based flexible storage and filtering functionality. It offers biologists and bioinformatics generalists easy-to-use and scalable analysis and prioritization of genomic variants from large cohort studies. VAPr is developed in Python and is available for free use and extension under the MIT License. An install package is available on PyPi at https://pypi.python.org/pypi/VAPr, while source code and extensive documentation are on GitHub at https://github.com/ucsd-ccbb/VAPr. kfisch@ucsd.edu.

Evaluating disease management program effectiveness: an introduction to time-series analysis.

PubMed

Linden, Ariel; Adams, John L; Roberts, Nancy

2003-01-01

Currently, the most widely used method in the disease management (DM) industry for evaluating program effectiveness is referred to as the "total population approach." This model is a pretest-posttest design, with the most basic limitation being that without a control group, there may be sources of bias and/or competing extraneous confounding factors that offer a plausible rationale explaining the change from baseline. Furthermore, with the current inclination of DM programs to use financial indicators rather than program-specific utilization indicators as the principal measure of program success, additional biases are introduced that may cloud evaluation results. This paper presents a non-technical introduction to time-series analysis (using disease-specific utilization measures) as an alternative, and more appropriate, approach to evaluating DM program effectiveness than the current total population approach.

Comparison of burbot populations across adjacent native and introduced ranges

USGS Publications Warehouse

Walters, Annika W.; Mandeville, Elizabeth G.; Saunders, W. Carl; Gerrity, Paul C.; Skorupski, Joseph A.; Underwood, Zachary E.; Gardunio, Eric I.

2017-01-01

Introduced species are a threat to biodiversity. Burbot, Lota lota, a fish native to the Wind River Drainage, Wyoming and a species of conservation concern, have been introduced into the nearby Green River Drainage, Wyoming, where they are having negative effects on native fish species. We compared these native and introduced burbot populations to evaluate potential mechanisms that could be leading to introduction success. We examined genetic ancestry, physical habitat characteristics, community composition, and burbot abundance, relative weight, and size structure between the native and introduced range to elucidate potential differences. The origin of introduced burbot in Flaming Gorge Reservoir is most likely Boysen Reservoir and several nearby river populations in the native Wind River Drainage. Burbot populations did not show consistent differences in abundance, size structure, and relative weight between drainages, though Fontenelle Reservoir, in the introduced drainage, had the largest burbot. There were also limited environmental and community composition differences, though reservoirs in the introduced drainage had lower species richness and a higher percentage of non-native fish species than the reservoir in the native drainage. Burbot introduction in the Green River Drainage is likely an example of reservoir construction creating habitat with suitable environmental conditions to allow a southwards range expansion of this cold-water species. An understanding of the factors driving introduction success can allow better management of species, both in their introduced and native range.

Inferring the Provenance of an Alien Species with DNA Barcodes: The Neotropical Butterfly Dryas iulia in Thailand

PubMed Central

Burg, Noah A.; Pradhan, Ashman; Gonzalez, Rebecca M.; Morban, Emely Z.; Zhen, Erica W.; Sakchoowong, Watana; Lohman, David J.

2014-01-01

The Neotropical butterfly Dryas iulia has been collected from several locations in Thailand and Malaysia since 2007, and has been observed breeding in the wild, using introduced Passiflora foetida as a larval host plant. The butterfly is bred by a butterfly house in Phuket, Thailand, for release at weddings and Buddhist ceremonies, and we hypothesized that this butterfly house was the source of wild, Thai individuals. We compared wing patterns and COI barcodes from two, wild Thai populations with individuals obtained from this butterfly house. All Thai individuals resemble the subspecies D. iulia modesta, and barcodes from wild and captive Thai specimens were identical. This unique, Thai barcode was not found in any of the 30 specimens sampled from the wild in the species' native range, but is most similar to specimens from Costa Rica, where many exporting butterfly farms are located. These data implicate the butterfly house as the source of Thailand's wild D. iulia populations, which are currently so widespread that eradication efforts are unlikely to be successful. PMID:25119899

Inferring the provenance of an alien species with DNA barcodes: the neotropical butterfly Dryas iulia in Thailand.

PubMed

Burg, Noah A; Pradhan, Ashman; Gonzalez, Rebecca M; Morban, Emely Z; Zhen, Erica W; Sakchoowong, Watana; Lohman, David J

2014-01-01

The Neotropical butterfly Dryas iulia has been collected from several locations in Thailand and Malaysia since 2007, and has been observed breeding in the wild, using introduced Passiflora foetida as a larval host plant. The butterfly is bred by a butterfly house in Phuket, Thailand, for release at weddings and Buddhist ceremonies, and we hypothesized that this butterfly house was the source of wild, Thai individuals. We compared wing patterns and COI barcodes from two, wild Thai populations with individuals obtained from this butterfly house. All Thai individuals resemble the subspecies D. iulia modesta, and barcodes from wild and captive Thai specimens were identical. This unique, Thai barcode was not found in any of the 30 specimens sampled from the wild in the species' native range, but is most similar to specimens from Costa Rica, where many exporting butterfly farms are located. These data implicate the butterfly house as the source of Thailand's wild D. iulia populations, which are currently so widespread that eradication efforts are unlikely to be successful.

Genetic origins of the Minoans and Mycenaeans

PubMed Central

Lazaridis, Iosif; Mittnik, Alissa; Patterson, Nick; Mallick, Swapan; Rohland, Nadin; Pfrengle, Saskia; Furtwängler, Anja; Peltzer, Alexander; Posth, Cosimo; Vasilakis, Andonis; McGeorge, P.J.P.; Konsolaki-Yannopoulou, Eleni; Korres, George; Martlew, Holley; Michalodimitrakis, Manolis; Özsait, Mehmet; Özsait, Nesrin; Papathanasiou, Anastasia; Richards, Michael; Roodenberg, Songül Alpaslan; Tzedakis, Yannis; Arnott, Robert; Fernandes, Daniel M.; Hughey, Jeffery R.; Lotakis, Dimitra M.; Navas, Patrick A.; Maniatis, Yannis; Stamatoyannopoulos, John A.; Stewardson, Kristin; Stockhammer, Philipp; Pinhasi, Ron; Reich, David; Krause, Johannes; Stamatoyannopoulos, George

2017-01-01

The origins of the Bronze Age Minoan and Mycenaean cultures have puzzled archaeologists for more than a century. We assembled genome-wide data from nineteen ancient individuals, including Minoans from Crete, Mycenaeans from mainland Greece, and their eastern neighbours from southwestern Anatolia. We show that Minoans and Mycenaeans were genetically similar, having at least three quarters of their ancestry from the first Neolithic farmers of western Anatolia and the Aegean1,2, and most of the remainder from ancient populations like those of the Caucasus3 and Iran4,5. However, the Mycenaeans differed from Minoans in deriving additional ancestry from an ultimate source related to the hunter-gatherers of eastern Europe and Siberia6–8, introduced via a proximal source related to either the inhabitants of either the Eurasian steppe1,6,9 or Armenia4,9. Modern Greeks resemble the Mycenaeans, but with some additional dilution of the early Neolithic ancestry. Our results support the idea of continuity but not isolation in the history of populations of the Aegean, before and after the time of its earliest civilizations. PMID:28783727

Specificity of extrafloral nectar induction by herbivores differs among native and invasive populations of tallow tree.

PubMed

Wang, Yi; Carrillo, Juli; Siemann, Evan; Wheeler, Gregory S; Zhu, Lin; Gu, Xue; Ding, Jianqing

2013-08-01

Invasive plants can be released from specialist herbivores and encounter novel generalists in their introduced ranges, leading to variation in defence among native and invasive populations. However, few studies have examined how constitutive and induced indirect defences change during plant invasion, especially during the juvenile stage. Constitutive extrafloral nectar (EFN) production of native and invasive populations of juvenile tallow tree (Triadica sebifera) were compared, and leaf clipping, and damage by a native specialist (Noctuid) and two native generalist caterpillars (Noctuid and Limacodid) were used to examine inducible EFN production. Plants from introduced populations had more leaves producing constitutive EFN than did native populations, but the content of soluble solids of EFN did not differ. Herbivores induced EFN production more than simulated herbivory. The specialist (Noctuid) induced more EFN than either generalist for native populations. The content of soluble solids in EFN was higher (2·1 times), with the specialist vs. the generalists causing the stronger response for native populations, but the specialist response was always comparable with the generalist responses for invasive populations. These results suggest that constitutive and induced indirect defences are retained in juvenile plants of invasive populations even during plant establishment, perhaps due to generalist herbivory in the introduced range. However, responses specific to a specialist herbivore may be reduced in the introduced range where specialists are absent. This decreased defence may benefit specialist insects that are introduced for classical biological control of invasive plants.

Regional distribution of introduced plant species in the forests of the Northeastern United States

Treesearch

Beth Schulz; W. Keith Moser; Cassandra Olson; Katherine Johnson

2013-01-01

Many plant species have been introduced to the United States by humans since European settlement, sometimes deliberately and sometimes inadvertently, such as in contaminated crop seed or soil. Some species have successfully escaped cultivation and become invasive, spreading and establishing new populations distant from original population centers. Indeed, introduced...

Lower resistance and higher tolerance of invasive host plants: biocontrol agents reach high densities but exert weak control.

PubMed

Wang, Yi; Huang, Wei; Siemann, Evan; Zou, Jianwen; Wheeler, Gregory S; Carrillo, Juli; Ding, Jianqing

2011-04-01

Invasive plants often have novel biotic interactions in their introduced ranges. Their defense to herbivory may differ from their native counterparts, potentially influencing the effectiveness of biological control. If invasive plants have decreased resistance but increased tolerance to enemies, insect herbivores may rapidly build up their populations but exert weak control. Moreover, resource availability to plants may affect the efficacy of biological control agents. We tested these predictions using Chinese tallow tree (Triadica sebifera) and two specialist herbivores (Heterapoderopsis bicallosicollis and Gadirtha inexacta) that are candidates for biological control. We performed a pair of field common garden experiments in China in which Triadica seedlings from the native or introduced range were grown in low or high light conditions and subjected to different levels of herbivory by each herbivore in a factorial design. We found that Heterapoderopsis achieved greater densities on tallow trees from the introduced range or when trees were grown in high light conditions. When Gadirtha was raised in the lab on tallow tree foliage we found that it performed better (larger pupal size) when fed foliage from introduced populations. However, introduced populations generally had greater herbivore tolerance such that the impact of each agent on plant performance was lower than on native populations despite higher herbivore loads. Tallow trees grew more slowly and achieved smaller sizes in lower light levels, but the impact of biological control agents was comparable to that found for higher light levels. Plants from introduced populations grew larger than those from native populations in all conditions. Our results suggest that reduced resistance and increased tolerance to herbivory in introduced populations may impede success of biological control programs. Biological control practitioners should include plants from the introduced range in the prerelease evaluation, which will help predict insect impact on target weeds.

Molecular evidence for a founder effect in invasive house finch (Carpodacus mexicanus) populations experiencing an emergent disease epidemic.

PubMed

Hawley, Dana M; Hanley, Daniel; Dhondt, André A; Lovette, Irby J

2006-01-01

The impact of founder events on levels of genetic variation in natural populations remains a topic of significant interest. Well-documented introductions provide a valuable opportunity to examine how founder events influence genetic diversity in invasive species. House finches (Carpodacus mexicanus) are passerine birds native to western North America, with the large eastern North American population derived from a small number of captive individuals released in the 1940s. Previous comparisons using amplified fragment length polymorphism (AFLP) markers found equivalent levels of diversity in eastern and western populations, suggesting that any genetic effects of the founder event were ameliorated by the rapid growth of the newly established population. We used an alternative marker system, 10 highly polymorphic microsatellites, to compare levels of genetic diversity between four native and five introduced house finch populations. In contrast to the AFLP comparisons, we found significantly lower allelic richness and heterozygosity in introduced populations across all loci. Three out of five introduced populations showed significant reductions in the ratio of the number of alleles to the allele size range, a within-population characteristic of recent bottlenecks. Finally, native and introduced populations showed significant pairwise differences in allele frequencies in every case, with stronger isolation by distance within the introduced than native range. Overall, our results provide compelling molecular evidence for a founder effect during the introduction of eastern house finches that reduced diversity levels at polymorphic microsatellite loci and may have contributed to the emergence of the Mycoplasma epidemic which recently swept the eastern range of this species.

A Bayesian Machine Learning Model for Estimating Building Occupancy from Open Source Data

DOE PAGES

Stewart, Robert N.; Urban, Marie L.; Duchscherer, Samantha E.; ...

2016-01-01

Understanding building occupancy is critical to a wide array of applications including natural hazards loss analysis, green building technologies, and population distribution modeling. Due to the expense of directly monitoring buildings, scientists rely in addition on a wide and disparate array of ancillary and open source information including subject matter expertise, survey data, and remote sensing information. These data are fused using data harmonization methods which refer to a loose collection of formal and informal techniques for fusing data together to create viable content for building occupancy estimation. In this paper, we add to the current state of the artmore » by introducing the Population Data Tables (PDT), a Bayesian based informatics system for systematically arranging data and harmonization techniques into a consistent, transparent, knowledge learning framework that retains in the final estimation uncertainty emerging from data, expert judgment, and model parameterization. PDT probabilistically estimates ambient occupancy in units of people/1000ft2 for over 50 building types at the national and sub-national level with the goal of providing global coverage. The challenge of global coverage led to the development of an interdisciplinary geospatial informatics system tool that provides the framework for capturing, storing, and managing open source data, handling subject matter expertise, carrying out Bayesian analytics as well as visualizing and exporting occupancy estimation results. We present the PDT project, situate the work within the larger community, and report on the progress of this multi-year project.Understanding building occupancy is critical to a wide array of applications including natural hazards loss analysis, green building technologies, and population distribution modeling. Due to the expense of directly monitoring buildings, scientists rely in addition on a wide and disparate array of ancillary and open source information including subject matter expertise, survey data, and remote sensing information. These data are fused using data harmonization methods which refer to a loose collection of formal and informal techniques for fusing data together to create viable content for building occupancy estimation. In this paper, we add to the current state of the art by introducing the Population Data Tables (PDT), a Bayesian model and informatics system for systematically arranging data and harmonization techniques into a consistent, transparent, knowledge learning framework that retains in the final estimation uncertainty emerging from data, expert judgment, and model parameterization. PDT probabilistically estimates ambient occupancy in units of people/1000 ft 2 for over 50 building types at the national and sub-national level with the goal of providing global coverage. The challenge of global coverage led to the development of an interdisciplinary geospatial informatics system tool that provides the framework for capturing, storing, and managing open source data, handling subject matter expertise, carrying out Bayesian analytics as well as visualizing and exporting occupancy estimation results. We present the PDT project, situate the work within the larger community, and report on the progress of this multi-year project.« less

Ecotypic variation in recruitment of reintroduced bighorn sheep: implications for translocation

USGS Publications Warehouse

Wiedmann, Brett P.; Sargeant, Glen A.

2014-01-01

European settlement led to extirpation of native Audubon's bighorn sheep (formerly Ovis canadensis auduboni) from North Dakota during the early 20th century. The North Dakota Game and Fish Department subsequently introduced California bighorn sheep (formerly O. c. californiana) that were indigenous to the Williams Lake region of British Columbia, Canada, and Rocky Mountain bighorn sheep (O. c. canadensis) that were indigenous to the Sun River region of Montana. Although California bighorn sheep are no longer recognized as a distinct subspecies, they are smaller and adapted to a milder climate than either the native bighorn sheep of North Dakota or introduced bighorn sheep from Montana. Because reintroductions still play a key role in the management of bighorn sheep and because local adaptation may have substantial demographic consequences, we evaluated causes of variation in recruitment of bighorn sheep reintroduced in North Dakota. During 2006–2011, Montana stock recruited 0.54 juveniles/adult female (n = 113), whereas British Columbia stock recruited 0.24 juveniles/adult female (n = 562). Our most plausible mixed-effects logistic regression model (53% of model weight) attributed variation in recruitment to differences between source populations (odds ratio = 4.5; 90% CI = 1.5, 15.3). Greater recruitment of Montana stock (fitted mean = 0.56 juveniles/adult female; 90% CI = 0.41, 0.70) contributed to a net gain in abundance (r = 0.15), whereas abundance of British Columbia stock declined (fitted mean = 0.24 juveniles/adult female; 90% CI = 0.09, 0.41; r = − 0.04). Translocations have been the primary tool used to augment and restore populations of wild sheep but often have failed to achieve objectives. Our results show that ecotypic differences among source stocks may have long-term implications for recruitment and demographic performance of reintroduced populations.

Sex Distribution of Paper Mulberry (Broussonetia papyrifera) in the Pacific

PubMed Central

Peñailillo, Johany; Olivares, Gabriela; Moncada, Ximena; Payacán, Claudia; Chang, Chi-Shan; Chung, Kuo-Fang; Matthews, Peter J.; Seelenfreund, Andrea; Seelenfreund, Daniela

2016-01-01

Background Paper mulberry (Broussonetia papyrifera (L.) L'Hér. ex Vent) is a dioecious tree native to East Asia and mainland Southeast-Asia, introduced prehistorically to Polynesia as a source of bark fiber by Austronesian-speaking voyagers. In Oceania, trees are coppiced and harvested for production of bark-cloth, so flowering is generally unknown. A survey of botanical records of paper mulberry revealed a distributional disjunction: the tree is apparently absent in Borneo and the Philippines. A subsequent study of chloroplast haplotypes linked paper mulberry of Remote Oceania directly to a population in southern Taiwan, distinct from known populations in mainland Southeast-Asia. Methodology We describe the optimization and use of a DNA marker designed to identify sex in paper mulberry. We used this marker to determine the sex distribution in selected localities across Asia, Near and Remote Oceania. We also characterized all samples using the ribosomal internal transcribed spacer sequence (ITS) in order to relate results to a previous survey of ITS diversity. Results In Near and Remote Oceania, contemporary paper mulberry plants are all female with the exception of Hawaii, where plants of both sexes are found. In its natural range in Asia, male and female plants are found, as expected. Male plants in Hawaii display an East Asian ITS genotype, consistent with modern introduction, while females in Remote Oceania share a distinctive variant. Conclusions Most paper mulberry plants now present in the Pacific appear to be descended from female clones introduced prehistorically. In Hawaii, the presence of male and female plants is thought to reflect a dual origin, one a prehistoric female introduction and the other a modern male introduction by Japanese/Chinese immigrants. If only female clones were dispersed from a source-region in Taiwan, this may explain the absence of botanical records and breeding populations in the Philippines and Borneo, and Remote Oceania. PMID:27529483

Sex Distribution of Paper Mulberry (Broussonetia papyrifera) in the Pacific.

PubMed

Peñailillo, Johany; Olivares, Gabriela; Moncada, Ximena; Payacán, Claudia; Chang, Chi-Shan; Chung, Kuo-Fang; Matthews, Peter J; Seelenfreund, Andrea; Seelenfreund, Daniela

2016-01-01

Paper mulberry (Broussonetia papyrifera (L.) L'Hér. ex Vent) is a dioecious tree native to East Asia and mainland Southeast-Asia, introduced prehistorically to Polynesia as a source of bark fiber by Austronesian-speaking voyagers. In Oceania, trees are coppiced and harvested for production of bark-cloth, so flowering is generally unknown. A survey of botanical records of paper mulberry revealed a distributional disjunction: the tree is apparently absent in Borneo and the Philippines. A subsequent study of chloroplast haplotypes linked paper mulberry of Remote Oceania directly to a population in southern Taiwan, distinct from known populations in mainland Southeast-Asia. We describe the optimization and use of a DNA marker designed to identify sex in paper mulberry. We used this marker to determine the sex distribution in selected localities across Asia, Near and Remote Oceania. We also characterized all samples using the ribosomal internal transcribed spacer sequence (ITS) in order to relate results to a previous survey of ITS diversity. In Near and Remote Oceania, contemporary paper mulberry plants are all female with the exception of Hawaii, where plants of both sexes are found. In its natural range in Asia, male and female plants are found, as expected. Male plants in Hawaii display an East Asian ITS genotype, consistent with modern introduction, while females in Remote Oceania share a distinctive variant. Most paper mulberry plants now present in the Pacific appear to be descended from female clones introduced prehistorically. In Hawaii, the presence of male and female plants is thought to reflect a dual origin, one a prehistoric female introduction and the other a modern male introduction by Japanese/Chinese immigrants. If only female clones were dispersed from a source-region in Taiwan, this may explain the absence of botanical records and breeding populations in the Philippines and Borneo, and Remote Oceania.

No evidence for increased performance of a specialist psyllid on invasive French broom

NASA Astrophysics Data System (ADS)

Herrera, Angelica M.; Carruthers, Raymond I.; Mills, Nicholas J.

2011-03-01

Some invasive plants perform better in their area of introduction than in their native region. This may be a consequence of rapid evolutionary change due to different selection pressures encountered in introduced regions. The Evolution of Increased Competitive Ability hypothesis (EICA) suggests that release from natural enemies results in selection of more vigorous plant genotypes as a result of plants allocating resources away from costly herbivore-resistance traits and toward increased growth. We tested the prediction that introduced plant genotypes of Genista monspessulana (Fabaceae) are less resistant to herbivory by a specialist psyllid, Arytinnis hakani (Hemiptera: Psyllidae) by measuring and comparing A. hakani performance on plants from native (southern France) and introduced (California, U.S.) populations. A. hakani performed equally well on plants from the native and introduced regions; there were no significant differences in psyllid egg and nymphal development, nymphal survival rates, female longevity or fecundity between the test plants. Egg survival rates were significantly higher on native populations, but the difference was minimal. These results provide preliminary evidence that native and introduced G. monspessulana populations are equally resistant to A. hakani and do not support the EICA hypothesis prediction of reduced investment in defense in introduced plant populations. Possible explanations for the lack of effects found in this study include the type of parameters measured and the feeding ecology of the herbivore used to test EICA, and finally, that evolutionary changes in plant defense in introduced G. monspessulana populations may not have occurred.

Gene screening of Wharton's jelly derived stem cells.

PubMed

Mechiche Alami, S; Velard, F; Draux, F; Siu Paredes, F; Josse, J; Lemaire, F; Gangloff, S C; Graesslin, O; Laurent-Maquin, D; Kerdjoudj, H

2014-01-01

Stem cells are the most powerful candidate for the treatment of various diseases. Suitable stem cell source should be harvested with minimal invasive procedure, found in great quantity, and transplanted with no risk of immune response and tumor formation. Fetal derived stem cells have been introduced as an excellent alternative to adult and embryonic stem cells use, but unfortunately, their degree of "stemness" and molecular characterization is still unclear. Several studies have been performed deciphering whether fetal stem cells meet the needs of regenerative medicine. We believe that a transcriptomic screening of Wharton's jelly stem cells will bring insights on cell population features.

Specificity of extrafloral nectar induction by herbivores differs among native and invasive populations of tallow tree

PubMed Central

Wang, Yi; Carrillo, Juli; Siemann, Evan; Wheeler, Gregory S.; Zhu, Lin; Gu, Xue; Ding, Jianqing

2013-01-01

Background and Aims Invasive plants can be released from specialist herbivores and encounter novel generalists in their introduced ranges, leading to variation in defence among native and invasive populations. However, few studies have examined how constitutive and induced indirect defences change during plant invasion, especially during the juvenile stage. Methods Constitutive extrafloral nectar (EFN) production of native and invasive populations of juvenile tallow tree (Triadica sebifera) were compared, and leaf clipping, and damage by a native specialist (Noctuid) and two native generalist caterpillars (Noctuid and Limacodid) were used to examine inducible EFN production. Key results Plants from introduced populations had more leaves producing constitutive EFN than did native populations, but the content of soluble solids of EFN did not differ. Herbivores induced EFN production more than simulated herbivory. The specialist (Noctuid) induced more EFN than either generalist for native populations. The content of soluble solids in EFN was higher (2·1 times), with the specialist vs. the generalists causing the stronger response for native populations, but the specialist response was always comparable with the generalist responses for invasive populations. Conclusions These results suggest that constitutive and induced indirect defences are retained in juvenile plants of invasive populations even during plant establishment, perhaps due to generalist herbivory in the introduced range. However, responses specific to a specialist herbivore may be reduced in the introduced range where specialists are absent. This decreased defence may benefit specialist insects that are introduced for classical biological control of invasive plants. PMID:23761685

Distance biases in the estimation of the physical properties of Hi-GAL compact sources - I. Clump properties and the identification of high-mass star-forming candidates

NASA Astrophysics Data System (ADS)

Baldeschi, Adriano; Elia, D.; Molinari, S.; Pezzuto, S.; Schisano, E.; Gatti, M.; Serra, A.; Merello, M.; Benedettini, M.; Di Giorgio, A. M.; Liu, J. S.

2017-04-01

The degradation of spatial resolution in star-forming regions, observed at large distances (d ≳ 1 kpc) with Herschel, can lead to estimates of the physical parameters of the detected compact sources (clumps), which do not necessarily mirror the properties of the original population of cores. This paper aims at quantifying the bias introduced in the estimation of these parameters by the distance effect. To do so, we consider Herschel maps of nearby star-forming regions taken from the Herschel Gould Belt survey, and simulate the effect of increased distance to understand what amount of information is lost when a distant star-forming region is observed with Herschel resolution. In the maps displaced to different distances we extract compact sources, and we derive their physical parameters as if they were original Herschel infrared Galactic Plane Survey maps of the extracted source samples. In this way, we are able to discuss how the main physical properties change with distance. In particular, we discuss the ability of clumps to form massive stars: we estimate the fraction of distant sources that are classified as high-mass stars-forming objects due to their position in the mass versus radius diagram, that are only 'false positives'. We also give a threshold for high-mass star formation M>1282 (r/ [pc])^{1.42} M_{⊙}. In conclusion, this paper provides the astronomer dealing with Herschel maps of distant star-forming regions with a set of prescriptions to partially recover the character of the core population in unresolved clumps.

Selection bias and patterns of confounding in cohort studies: the case of the NINFEA web-based birth cohort.

PubMed

Pizzi, Costanza; De Stavola, Bianca L; Pearce, Neil; Lazzarato, Fulvio; Ghiotti, Paola; Merletti, Franco; Richiardi, Lorenzo

2012-11-01

Several studies have examined the effects of sample selection on the exposure-outcome association estimates in cohort studies, but the reasons why this selection may induce bias have not been fully explored. To investigate how sample selection of the web-based NINFEA birth cohort may change the confounding patterns present in the source population. The characteristics of the NINFEA participants (n=1105) were compared with those of the wider source population-the Piedmont Birth Registry (PBR)-(n=36 092), and the association of two exposures (parity and educational level) with two outcomes (low birth weight and birth by caesarean section), while controlling for other risk factors, was studied. Specifically the associations among measured risk factors within each dataset were examined and the exposure-outcome estimates compared in terms of relative ORs. The associations of educational level with the other risk factors (alcohol consumption, folic acid intake, maternal age, pregnancy weight gain, previous miscarriages) partly differed between PBR and NINFEA. This was not observed for parity. Overall, the exposure-outcome estimates derived from NINFEA only differed moderately from those obtained in PBR, with relative ORs ranging between 0.74 and 1.03. Sample selection in cohort studies may alter the confounding patterns originally present in the general population. However, this does not necessarily introduce selection bias in the exposure-outcome estimates, as sample selection may reduce some of the residual confounding present in the general population.

Reproductive dormancy in boll-weevil from populations of the midwest of Brazil.

PubMed

Paula, D P; Claudino, D; Timbó, R V; Miranda, J E; Bemquerer, M P; Ribeiro, A C J; Sujii, E R; Fontes, E M G; Pires, C S S

2013-02-01

The boll weevil (Anthonomus grandis Boheman) (Coleoptera: Curculionidae) is an introduced pest in Brazil, which in 30 yr has successfully expanded to various eco-regions and became the most important pest of cotton (Gossypium hirsutum, Malvaceae). Given the limited knowledge about the adaptive mechanisms that allowed successful establishment of the pest population in a tropical region, in this work we studied the potential of the Midwest population of boll weevils to enter a reproductive dormancy and identified the importance of the feeding source for induction of dormancy. We investigated morphological and physiological characters as indicators of the dormancy. We also investigated the occurrence of reproductive dormancy in boll weevils populations from cotton farms of the Midwestern region of Brazil during the cotton and noncotton seasons of 2009 and 2010. The studies revealed that boll weevils entered facultative reproductive dormancy; however, unlike what has been observed for boll weevils from temperate and subtropical regions, the hypertrophy of fat body and hexamerin levels did not straightly correlated to reproductive dormancy. The food source and field conditions during early adult development were decisive factor for the induction of reproductive dormancy. The incidence of reproductive dormancy increased progressively as the phenology of cotton plant advanced, reaching approximately 90% at the end of the crop season. During the noncotton season, the boll weevil was predominantly found in reproductive dormancy, especially females; however, there is evidence of use of multiple adaptive strategies to colonize the next harvest.

Comparative genetic diversity in a sample of pony breeds from the U.K. and North America: a case study in the conservation of global genetic resources.

PubMed

Winton, Clare L; Plante, Yves; Hind, Pamela; McMahon, Robert; Hegarty, Matthew J; McEwan, Neil R; Davies-Morel, Mina C G; Morgan, Charly M; Powell, Wayne; Nash, Deborah M

2015-08-01

Most species exist as subdivided ex situ daughter population(s) derived from a single original group of individuals. Such subdivision occurs for many reasons both natural and manmade. Traditional British and Irish pony breeds were introduced to North America (U.S.A. and Canada) within the last 150 years, and subsequently equivalent breed societies were established. We have analyzed selected U.K. and North American equivalent pony populations as a case study for understanding the relationship between putative source and derived subpopulations. Diversity was measured using mitochondrial DNA and a panel of microsatellite markers. Genetic signatures differed between the North American subpopulations according to historical management processes. Founder effect and stochastic drift was apparent, particularly pronounced in some breeds, with evidence of admixture of imported mares of different North American breeds. This demonstrates the importance of analysis of subpopulations to facilitate understanding the genetic effects of past management practices and to lead to informed future conservation strategies.

Rapid change in the thermal tolerance of a tropical lizard.

PubMed

Leal, Manuel; Gunderson, Alex R

2012-12-01

The predominant view is that the thermal physiology of tropical ectotherms, including lizards, is not labile over ecological timescales. We used the recent introduction (∼35 years ago) of the Puerto Rican lizard Anolis cristatellus to Miami, Florida, to test this thermal rigidity hypothesis. We measured lower (critical thermal minimum [CT(min)]) and upper (critical thermal maximum [CT(max)]) thermal tolerances and found that the introduced population tolerates significantly colder temperatures (by ∼3°C) than does the Puerto Rican source population; however, CT(max) did not differ. These results mirror the thermal regimes experienced by each population: Miami reaches colder ambient temperatures than Puerto Rico, but maximum ambient temperatures are similar. The differences in CT(min) were observed even though lizards from both sites experienced nearly identical conditions for 49 days before CT(min) measurement. Our results demonstrate that changes in thermal tolerance occurred relatively rapidly (∼35 generations), which strongly suggests that the thermal physiology of tropical lizards is more labile than previously proposed.

Uncertainty in gridded CO 2 emissions estimates

DOE PAGES

Hogue, Susannah; Marland, Eric; Andres, Robert J.; ...

2016-05-19

We are interested in the spatial distribution of fossil-fuel-related emissions of CO 2 for both geochemical and geopolitical reasons, but it is important to understand the uncertainty that exists in spatially explicit emissions estimates. Working from one of the widely used gridded data sets of CO 2 emissions, we examine the elements of uncertainty, focusing on gridded data for the United States at the scale of 1° latitude by 1° longitude. Uncertainty is introduced in the magnitude of total United States emissions, the magnitude and location of large point sources, the magnitude and distribution of non-point sources, and from themore » use of proxy data to characterize emissions. For the United States, we develop estimates of the contribution of each component of uncertainty. At 1° resolution, in most grid cells, the largest contribution to uncertainty comes from how well the distribution of the proxy (in this case population density) represents the distribution of emissions. In other grid cells, the magnitude and location of large point sources make the major contribution to uncertainty. Uncertainty in population density can be important where a large gradient in population density occurs near a grid cell boundary. Uncertainty is strongly scale-dependent with uncertainty increasing as grid size decreases. In conclusion, uncertainty for our data set with 1° grid cells for the United States is typically on the order of ±150%, but this is perhaps not excessive in a data set where emissions per grid cell vary over 8 orders of magnitude.« less

Monitoring the establishment and prevalence of the fungal entomopathogen Entomophaga maimaiga in two Lymantria dispar L. populations in Bulgaria

Treesearch

D. Pilarska; M. McManus; P. Pilarska; G. Georgiev; P. Mirchev; A. Linde

2005-01-01

The establishment and prevalence of the entomopathogenic fungus Entomophaga maimaiga, (Zygomycetes, Entomophthorales), introduced into two gypsy moth populations in Bulgaria, was monitored during 2000-2004. In the Karlovo Region population, where E. maimaiga was introduced in 1999, the fungus was recovered every year and the...

Invasion of sorghum in the Americas by a new sugarcane aphid (Melanaphis sacchari) superclone.

PubMed

Nibouche, Samuel; Costet, Laurent; Holt, Jocelyn R; Jacobson, Alana; Pekarcik, Adrian; Sadeyen, Joëlle; Armstrong, J Scott; Peterson, Gary C; McLaren, Neal; Medina, Raul F

2018-01-01

In the United States (US), the sugarcane aphid (SCA) Melanaphis sacchari (Zehnter) (Hemiptera: Aphididae) was introduced in the 1970s, however at that time it was only considered a pest of sugarcane. In 2013, a massive outbreak of M. sacchari occured on sorghum, resulting in significant economic damage to sorghum grown in North America including the US, Mexico, and Puerto Rico. The aim of the present study was to determine if the SCA pest emergence in American sorghum resulted from the introduction of new genotypes. To this end we used microsatellite markers and COI sequencing to compare the genetic diversity of SCA populations collected in the Americas after the 2013 SCA outbreak on sorghum (during 2013-2017) to older samples collected before the pest outbreak (during 2007-2009). Our results show that the SCA outbreak in the Americas and the Caribbean observed since 2013 belong to populations exhibiting low genetic diversity and consisting of a dominant clonal lineage, MLL-F, which colonizes Sorghum spp. and sugarcane. The comparison of MLL-F specimens collected post-2013 with specimens collected in Louisiana in 2007 revealed that both populations are genetically distinct, according to COI sequencing and microsatellite data analyses. Our result suggest that MLL-F is a new invasive genotype introduced into the Americas that has spread rapidly across sorghum growing regions in the US, Mexico, Honduras and the Caribbean. The origin of this introduction is either Africa or Asia, with Asia being the most probable source.

Incorporating parametric uncertainty into population viability analysis models

USGS Publications Warehouse

McGowan, Conor P.; Runge, Michael C.; Larson, Michael A.

2011-01-01

Uncertainty in parameter estimates from sampling variation or expert judgment can introduce substantial uncertainty into ecological predictions based on those estimates. However, in standard population viability analyses, one of the most widely used tools for managing plant, fish and wildlife populations, parametric uncertainty is often ignored in or discarded from model projections. We present a method for explicitly incorporating this source of uncertainty into population models to fully account for risk in management and decision contexts. Our method involves a two-step simulation process where parametric uncertainty is incorporated into the replication loop of the model and temporal variance is incorporated into the loop for time steps in the model. Using the piping plover, a federally threatened shorebird in the USA and Canada, as an example, we compare abundance projections and extinction probabilities from simulations that exclude and include parametric uncertainty. Although final abundance was very low for all sets of simulations, estimated extinction risk was much greater for the simulation that incorporated parametric uncertainty in the replication loop. Decisions about species conservation (e.g., listing, delisting, and jeopardy) might differ greatly depending on the treatment of parametric uncertainty in population models.

Fine-scale population genetic structure of a wildlife disease vector: The southern house mosquito on the island of Hawaii

USGS Publications Warehouse

Keyghobadi, N.; LaPointe, D.; Fleischer, R.C.; Fonseca, D.M.

2006-01-01

The southern house mosquito, Culex quinquefasciatus, is a widespread tropical and subtropical disease vector. In the Hawaiian Islands, where it was introduced accidentally almost two centuries ago, it is considered the primary vector of avian malaria and pox. Avian malaria in particular has contributed to the extinction and endangerment of Hawaii's native avifauna, and has altered the altitudinal distribution of native bird populations. We examined the population genetic structure of Cx. quinquefasciatus on the island of Hawaii at a smaller spatial scale than has previously been attempted, with particular emphasis on the effects of elevation on population genetic structure. We found significant genetic differentiation among populations and patterns of isolation by distance within the island. Elevation per se did not have a limiting effect on gene flow; however, there was significantly lower genetic diversity among populations at mid elevations compared to those at low elevations. A recent sample taken from just above the predicted upper altitudinal distribution of Cx. quinquefasciatus on the island of Hawaii was confirmed as being a temporary summer population and appeared to consist of individuals from more than one source population. Our results indicate effects of elevation gradients on genetic structure that are consistent with known effects of elevation on population dynamics of this disease vector. ?? 2006 The Authors.

Complete genome of Pieris rapae, a resilient alien, a cabbage pest, and a source of anti-cancer proteins

PubMed Central

Kinch, Lisa N.; Borek, Dominika; Otwinowski, Zbyszek; Grishin, Nick V.

2016-01-01

The Small Cabbage White ( Pieris rapae) is originally a Eurasian butterfly. Being accidentally introduced into North America, Australia, and New Zealand a century or more ago, it spread throughout the continents and rapidly established as one of the most abundant butterfly species. Although it is a serious pest of cabbage and other mustard family plants with its caterpillars reducing crops to stems, it is also a source of pierisin, a protein unique to the Whites that shows cytotoxicity to cancer cells. To better understand the unusual biology of this omnipresent agriculturally and medically important butterfly, we sequenced and annotated the complete genome from USA specimens. At 246 Mbp, it is among the smallest Lepidoptera genomes reported to date. While 1.5% positions in the genome are heterozygous, they are distributed highly non-randomly along the scaffolds, and nearly 20% of longer than 1000 base-pair segments are SNP-free (median length: 38000 bp). Computational simulations of population evolutionary history suggest that American populations started from a very small number of introduced individuals, possibly a single fertilized female, which is in agreement with historical literature. Comparison to other Lepidoptera genomes reveals several unique families of proteins that may contribute to the unusual resilience of Pieris. The nitrile-specifier proteins divert the plant defense chemicals to non-toxic products. The apoptosis-inducing pierisins could offer a defense mechanism against parasitic wasps. While only two pierisins from Pieris rapae were characterized before, the genome sequence revealed eight, offering additional candidates as anti-cancer drugs. The reference genome we obtained lays the foundation for future studies of the Cabbage White and other Pieridae species. PMID:28163896

Global Genetics and Invasion History of the Potato Powdery Scab Pathogen, Spongospora subterranea f.sp. subterranea

PubMed Central

Gau, Rebecca D.; Merz, Ueli; Falloon, Richard E.; Brunner, Patrick C.

2013-01-01

Spongospora subterranea f. sp. subterranea (Sss) causes two diseases on potato (Solanum tuberosum), lesions on tubers and galls on roots, which are economically important worldwide. Knowledge of global genetic diversity and population structure of pathogens is essential for disease management including resistance breeding. A combination of microsatellite and DNA sequence data was used to investigate the structure and invasion history of Sss. South American populations (four countries, 132 samples) were consistently more diverse than those from all other regions (15 countries, 566 samples), in agreement with the hypothesis that Sss originated in South America where potato was domesticated. A substantial genetic differenciation was found between root and tuber-derived samples from South America. Estimates of past and recent gene flow suggested that Sss was probably introduced from South America into Europe. Subsequently, Europe is likely to have been the recent source of migrants of the pathogen, acting as a “bridgehead” for further global dissemination. Quarantine measures must continue to be focussed on maintaining low global genetic diversity and avoiding exchange of genetic material between the native and introduced regions. Nevertheless, the current low global genetic diversity of Sss allows potato breeders to select for resistance, which is likely to be durable. PMID:23840791

Sensitivity of Earthquake Loss Estimates to Source Modeling Assumptions and Uncertainty

USGS Publications Warehouse

Reasenberg, Paul A.; Shostak, Nan; Terwilliger, Sharon

2006-01-01

Introduction: This report explores how uncertainty in an earthquake source model may affect estimates of earthquake economic loss. Specifically, it focuses on the earthquake source model for the San Francisco Bay region (SFBR) created by the Working Group on California Earthquake Probabilities. The loss calculations are made using HAZUS-MH, a publicly available computer program developed by the Federal Emergency Management Agency (FEMA) for calculating future losses from earthquakes, floods and hurricanes within the United States. The database built into HAZUS-MH includes a detailed building inventory, population data, data on transportation corridors, bridges, utility lifelines, etc. Earthquake hazard in the loss calculations is based upon expected (median value) ground motion maps called ShakeMaps calculated for the scenario earthquake sources defined in WGCEP. The study considers the effect of relaxing certain assumptions in the WG02 model, and explores the effect of hypothetical reductions in epistemic uncertainty in parts of the model. For example, it addresses questions such as what would happen to the calculated loss distribution if the uncertainty in slip rate in the WG02 model were reduced (say, by obtaining additional geologic data)? What would happen if the geometry or amount of aseismic slip (creep) on the region's faults were better known? And what would be the effect on the calculated loss distribution if the time-dependent earthquake probability were better constrained, either by eliminating certain probability models or by better constraining the inherent randomness in earthquake recurrence? The study does not consider the effect of reducing uncertainty in the hazard introduced through models of attenuation and local site characteristics, although these may have a comparable or greater effect than does source-related uncertainty. Nor does it consider sources of uncertainty in the building inventory, building fragility curves, and other assumptions adopted in the loss calculations. This is a sensitivity study aimed at future regional earthquake source modelers, so that they may be informed of the effects on loss introduced by modeling assumptions and epistemic uncertainty in the WG02 earthquake source model.

Bee++: An Object-Oriented, Agent-Based Simulator for Honey Bee Colonies

PubMed Central

Betti, Matthew; LeClair, Josh; Wahl, Lindi M.; Zamir, Mair

2017-01-01

We present a model and associated simulation package (www.beeplusplus.ca) to capture the natural dynamics of a honey bee colony in a spatially-explicit landscape, with temporally-variable, weather-dependent parameters. The simulation tracks bees of different ages and castes, food stores within the colony, pollen and nectar sources and the spatial position of individual foragers outside the hive. We track explicitly the intake of pesticides in individual bees and their ability to metabolize these toxins, such that the impact of sub-lethal doses of pesticides can be explored. Moreover, pathogen populations (in particular, Nosema apis, Nosema cerenae and Varroa mites) have been included in the model and may be introduced at any time or location. The ability to study interactions among pesticides, climate, biodiversity and pathogens in this predictive framework should prove useful to a wide range of researchers studying honey bee populations. To this end, the simulation package is written in open source, object-oriented code (C++) and can be easily modified by the user. Here, we demonstrate the use of the model by exploring the effects of sub-lethal pesticide exposure on the flight behaviour of foragers. PMID:28287445

General Suppression of Escherichia coli O157:H7 in Sand-Based Dairy Livestock Bedding▿ †

PubMed Central

Westphal, Andreas; Williams, Michele L.; Baysal-Gurel, Fulya; LeJeune, Jeffrey T.; McSpadden Gardener, Brian B.

2011-01-01

Sand bedding material is frequently used in dairy operations to reduce the occurrence of mastitis and enhance cow comfort. One objective of this work was to determine if sand-based bedding also supported the microbiologically based suppression of an introduced bacterial pathogen. Bedding samples were collected in summer, fall, and winter from various locations within a dairy operation and tested for their ability to suppress introduced populations of Escherichia coli O157:H7. All sources of bedding displayed a heat-sensitive suppressiveness to the pathogen. Differences in suppressiveness were also noted between different samples at room temperature. At just 1 day postinoculation (dpi), the recycled sand bedding catalyzed up to a 1,000-fold reduction in E. coli counts, typically 10-fold greater than the reduction achieved with other substrates, depending on the sampling date. All bedding substrates were able to reduce E. coli populations by over 10,000-fold within 7 to 15 dpi, regardless of sampling date. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to identify bacterial populations potentially associated with the noted suppression of E. coli O157:H7 in sand bedding. Eleven terminal restriction fragments (TRFs) were overrepresented in paired comparisons of suppressive and nonsuppressive specimens at multiple sampling points, indicating that they may represent environmentally stable populations of pathogen-suppressing bacteria. Cloning and sequencing of these TRFs indicated that they represent a diverse subset of bacteria, belonging to the Cytophaga-Flexibacter-Bacteroidetes, Gammaproteobacteria, and Firmicutes, only a few of which have previously been identified in livestock manure. Such data indicate that microbial suppression may be harnessed to develop new options for mitigating the risk and dispersal of zoonotic bacterial pathogens on dairy farms. PMID:21257815

Rapid scoring of genes in microbial pan-genome-wide association studies with Scoary.

PubMed

Brynildsrud, Ola; Bohlin, Jon; Scheffer, Lonneke; Eldholm, Vegard

2016-11-25

Genome-wide association studies (GWAS) have become indispensable in human medicine and genomics, but very few have been carried out on bacteria. Here we introduce Scoary, an ultra-fast, easy-to-use, and widely applicable software tool that scores the components of the pan-genome for associations to observed phenotypic traits while accounting for population stratification, with minimal assumptions about evolutionary processes. We call our approach pan-GWAS to distinguish it from traditional, single nucleotide polymorphism (SNP)-based GWAS. Scoary is implemented in Python and is available under an open source GPLv3 license at https://github.com/AdmiralenOla/Scoary .

Contrasting effects of specialist and generalist herbivores on resistance evolution in invasive plants.

PubMed

Zhang, Zhijie; Pan, Xiaoyun; Blumenthal, Dana; van Kleunen, Mark; Liu, Mu; Li, Bo

2018-04-01

Invasive alien plants are likely to be released from specialist herbivores and at the same time encounter biotic resistance from resident generalist herbivores in their new ranges. The Shifting Defense hypothesis predicts that this will result in evolution of decreased defense against specialist herbivores and increased defense against generalist herbivores. To test this, we performed a comprehensive meta-analysis of 61 common garden studies that provide data on resistance and/or tolerance for both introduced and native populations of 32 invasive plant species. We demonstrate that introduced populations, relative to native populations, decreased their resistance against specialists, and increased their resistance against generalists. These differences were significant when resistance was measured in terms of damage caused by the herbivore, but not in terms of performance of the herbivore. Furthermore, we found the first evidence that the magnitude of resistance differences between introduced and native populations depended significantly on herbivore origin (i.e., whether the test herbivore was collected from the native or non-native range of the invasive plant). Finally, tolerance to generalists was found to be higher in introduced populations, while neither tolerance to specialists nor that to simulated herbivory differed between introduced and native plant populations. We conclude that enemy release from specialist herbivores and biotic resistance from generalist herbivores have contrasting effects on resistance evolution in invasive plants. Our results thus provide strong support for the Shifting Defense hypothesis. © 2018 by the Ecological Society of America.

Systematic analysis of the contributions of stochastic voltage gated channels to neuronal noise

PubMed Central

O'Donnell, Cian; van Rossum, Mark C. W.

2014-01-01

Electrical signaling in neurons is mediated by the opening and closing of large numbers of individual ion channels. The ion channels' state transitions are stochastic and introduce fluctuations in the macroscopic current through ion channel populations. This creates an unavoidable source of intrinsic electrical noise for the neuron, leading to fluctuations in the membrane potential and spontaneous spikes. While this effect is well known, the impact of channel noise on single neuron dynamics remains poorly understood. Most results are based on numerical simulations. There is no agreement, even in theoretical studies, on which ion channel type is the dominant noise source, nor how inclusion of additional ion channel types affects voltage noise. Here we describe a framework to calculate voltage noise directly from an arbitrary set of ion channel models, and discuss how this can be use to estimate spontaneous spike rates. PMID:25360105

Uncertainty Quantification Techniques for Population Density Estimates Derived from Sparse Open Source Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, Robert N; White, Devin A; Urban, Marie L

2013-01-01

The Population Density Tables (PDT) project at the Oak Ridge National Laboratory (www.ornl.gov) is developing population density estimates for specific human activities under normal patterns of life based largely on information available in open source. Currently, activity based density estimates are based on simple summary data statistics such as range and mean. Researchers are interested in improving activity estimation and uncertainty quantification by adopting a Bayesian framework that considers both data and sociocultural knowledge. Under a Bayesian approach knowledge about population density may be encoded through the process of expert elicitation. Due to the scale of the PDT effort whichmore » considers over 250 countries, spans 40 human activity categories, and includes numerous contributors, an elicitation tool is required that can be operationalized within an enterprise data collection and reporting system. Such a method would ideally require that the contributor have minimal statistical knowledge, require minimal input by a statistician or facilitator, consider human difficulties in expressing qualitative knowledge in a quantitative setting, and provide methods by which the contributor can appraise whether their understanding and associated uncertainty was well captured. This paper introduces an algorithm that transforms answers to simple, non-statistical questions into a bivariate Gaussian distribution as the prior for the Beta distribution. Based on geometric properties of the Beta distribution parameter feasibility space and the bivariate Gaussian distribution, an automated method for encoding is developed that responds to these challenging enterprise requirements. Though created within the context of population density, this approach may be applicable to a wide array of problem domains requiring informative priors for the Beta distribution.« less

Forecasting wildlife response to rapid warming in the Alaskan Arctic

USGS Publications Warehouse

Van Hemert, Caroline R.; Flint, Paul L.; Udevitz, Mark S.; Koch, Joshua C.; Atwood, Todd C.; Oakley, Karen L.; Pearce, John M.

2015-01-01

Arctic wildlife species face a dynamic and increasingly novel environment because of climate warming and the associated increase in human activity. Both marine and terrestrial environments are undergoing rapid environmental shifts, including loss of sea ice, permafrost degradation, and altered biogeochemical fluxes. Forecasting wildlife responses to climate change can facilitate proactive decisions that balance stewardship with resource development. In this article, we discuss the primary and secondary responses to physical climate-related drivers in the Arctic, associated wildlife responses, and additional sources of complexity in forecasting wildlife population outcomes. Although the effects of warming on wildlife populations are becoming increasingly well documented in the scientific literature, clear mechanistic links are often difficult to establish. An integrated science approach and robust modeling tools are necessary to make predictions and determine resiliency to change. We provide a conceptual framework and introduce examples relevant for developing wildlife forecasts useful to management decisions.

Asymmetric Evolutionary Games.

PubMed

McAvoy, Alex; Hauert, Christoph

2015-08-01

Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner's Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games.

Computer simulations of sympatric speciation in a simple food web

NASA Astrophysics Data System (ADS)

Luz-Burgoa, K.; Dell, Tony; de Oliveira, S. Moss

2005-07-01

Galapagos finches, have motivated much theoretical research aimed at understanding the processes associated with the formation of the species. Inspired by them, in this paper we investigate the process of sympatric speciation in a simple food web model. For that we modify the individual-based Penna model that has been widely used to study aging as well as other evolutionary processes. Initially, our web consists of a primary food source and a single herbivore species that feeds on this resource. Subsequently we introduce a predator that feeds on the herbivore. In both instances we manipulate directly a basal resource distribution and monitor the changes in the populations. Sympatric speciation is obtained for the top species in both cases, and our results suggest that the speciation velocity depends on how far up, in the food chain, the focus population is feeding. Simulations are done with three different sexual imprintinglike mechanisms, in order to discuss adaptation by natural selection.

Mitochondria and the non-genetic origins of cell-to-cell variability: More is different.

PubMed

Guantes, Raúl; Díaz-Colunga, Juan; Iborra, Francisco J

2016-01-01

Gene expression activity is heterogeneous in a population of isogenic cells. Identifying the molecular basis of this variability will improve our understanding of phenomena like tumor resistance to drugs, virus infection, or cell fate choice. The complexity of the molecular steps and machines involved in transcription and translation could introduce sources of randomness at many levels, but a common constraint to most of these processes is its energy dependence. In eukaryotic cells, most of this energy is provided by mitochondria. A clonal population of cells may show a large variability in the number and functionality of mitochondria. Here, we discuss how differences in the mitochondrial content of each cell contribute to heterogeneity in gene products. Changes in the amount of mitochondria can also entail drastic alterations of a cell's gene expression program, which ultimately leads to phenotypic diversity. Also watch the Video Abstract. © 2015 WILEY Periodicals, Inc.

The effect of social alliances on wolf population on their survival under hunting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cebrat, S.; Kakol, J.

1997-04-01

We have introduced the modified Verhulst factor to simulate the dynamics of wolves` population. The new factor enlarges the capacity of environment for organisms living in organized groups. Under this factor, social behavior allows the population to reach the larger size in the same ecological niche. The other effect of the introduced factor is that additional non-selective killing factors limit the population size not only directly but also by shrinking the effective ecological niche capacity.

The Effect of Social Alliances on Wolf Population on Their Survival Under Hunting

NASA Astrophysics Data System (ADS)

Cebrat, Stanisław; Kakol, Jerzy

We have introduced the modified Verhulst factor to simulate the dynamics of wolves' population. The new factor enlarges the capacity of environment for organisms living in organized groups. Under this factor, social behavior allows the population to reach the larger size in the same ecological niche. The other effect of the introduced factor is that additional non-selective killing factors limit the population size not only directly but also by shrinking the effective ecological niche capacity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, Robert N.; Urban, Marie L.; Duchscherer, Samantha E.

Understanding building occupancy is critical to a wide array of applications including natural hazards loss analysis, green building technologies, and population distribution modeling. Due to the expense of directly monitoring buildings, scientists rely in addition on a wide and disparate array of ancillary and open source information including subject matter expertise, survey data, and remote sensing information. These data are fused using data harmonization methods which refer to a loose collection of formal and informal techniques for fusing data together to create viable content for building occupancy estimation. In this paper, we add to the current state of the artmore » by introducing the Population Data Tables (PDT), a Bayesian based informatics system for systematically arranging data and harmonization techniques into a consistent, transparent, knowledge learning framework that retains in the final estimation uncertainty emerging from data, expert judgment, and model parameterization. PDT probabilistically estimates ambient occupancy in units of people/1000ft2 for over 50 building types at the national and sub-national level with the goal of providing global coverage. The challenge of global coverage led to the development of an interdisciplinary geospatial informatics system tool that provides the framework for capturing, storing, and managing open source data, handling subject matter expertise, carrying out Bayesian analytics as well as visualizing and exporting occupancy estimation results. We present the PDT project, situate the work within the larger community, and report on the progress of this multi-year project.Understanding building occupancy is critical to a wide array of applications including natural hazards loss analysis, green building technologies, and population distribution modeling. Due to the expense of directly monitoring buildings, scientists rely in addition on a wide and disparate array of ancillary and open source information including subject matter expertise, survey data, and remote sensing information. These data are fused using data harmonization methods which refer to a loose collection of formal and informal techniques for fusing data together to create viable content for building occupancy estimation. In this paper, we add to the current state of the art by introducing the Population Data Tables (PDT), a Bayesian model and informatics system for systematically arranging data and harmonization techniques into a consistent, transparent, knowledge learning framework that retains in the final estimation uncertainty emerging from data, expert judgment, and model parameterization. PDT probabilistically estimates ambient occupancy in units of people/1000 ft 2 for over 50 building types at the national and sub-national level with the goal of providing global coverage. The challenge of global coverage led to the development of an interdisciplinary geospatial informatics system tool that provides the framework for capturing, storing, and managing open source data, handling subject matter expertise, carrying out Bayesian analytics as well as visualizing and exporting occupancy estimation results. We present the PDT project, situate the work within the larger community, and report on the progress of this multi-year project.« less

Plural provision of primary medical care in England, 2002-2012.

PubMed

Sheaff, Rod

2013-10-01

Health care reforms often include provider diversification, including privatization, to increase competition and thereby health care quality and efficiency. Donabedian's organizational theory implies that the consequences will vary according to the providers' ownership. The aim was to examine how far that theory applies to changes in English NHS primary medical care (general practice) since 1998, and the consequences for patterns of service provision. Framework analysis whose categories and structure reflected Donabedian's theory and its implications, populated with data from a systematic review, administrative sources and press rapportage. Two patterns of provider diversification occurred: 'native' diversification among existing providers and plural provision as providers with different types of ownership were introduced. Native diversification occurred through: extensive recruitment of salaried GPs; extending the range of services provided by general practices; introducing limited liability partnerships; establishing GPs with special clinical interests; and introducing a wider range of services for GPs to refer to. All of these had little apparent effect on competition between general practices. Plural provision involved: increased primary care provision by corporations; introducing GP-owned firms; establishing social enterprises (initially mostly out-of-hours cooperatives); and Primary Care Trusts taking over general practices. Plural provision was on a smaller scale than native diversification and appeared to go into reverse in 2011. Although the available data confirm the implications of Donabedian's theory, there are exceptions. Native diversification and plural provision policies differ in their implications for service development.

Computational inverse methods of heat source in fatigue damage problems

NASA Astrophysics Data System (ADS)

Chen, Aizhou; Li, Yuan; Yan, Bo

2018-04-01

Fatigue dissipation energy is the research focus in field of fatigue damage at present. It is a new idea to solve the problem of calculating fatigue dissipation energy by introducing inverse method of heat source into parameter identification of fatigue dissipation energy model. This paper introduces the research advances on computational inverse method of heat source and regularization technique to solve inverse problem, as well as the existing heat source solution method in fatigue process, prospects inverse method of heat source applying in fatigue damage field, lays the foundation for further improving the effectiveness of fatigue dissipation energy rapid prediction.

Volumetric Two-photon Imaging of Neurons Using Stereoscopy (vTwINS)

PubMed Central

Song, Alexander; Charles, Adam S.; Koay, Sue Ann; Gauthier, Jeff L.; Thiberge, Stephan Y.; Pillow, Jonathan W.; Tank, David W.

2017-01-01

Two-photon laser scanning microscopy of calcium dynamics using fluorescent indicators is a widely used imaging method for large scale recording of neural activity in vivo. Here we introduce volumetric Two-photon Imaging of Neurons using Stereoscopy (vTwINS), a volumetric calcium imaging method that employs an elongated, V-shaped point spread function to image a 3D brain volume. Single neurons project to spatially displaced “image pairs” in the resulting 2D image, and the separation distance between images is proportional to depth in the volume. To demix the fluorescence time series of individual neurons, we introduce a novel orthogonal matching pursuit algorithm that also infers source locations within the 3D volume. We illustrate vTwINS by imaging neural population activity in mouse primary visual cortex and hippocampus. Our results demonstrate that vTwINS provides an effective method for volumetric two-photon calcium imaging that increases the number of neurons recorded while maintaining a high frame-rate. PMID:28319111

Source identification of autochthonous-introduced Plasmodium vivax Malaria, Spain.

PubMed

Barrado, Laura; Ezpeleta, Carmen; Rubio, José Miguel; Martín, Carmen; Azcona, José Manuel; Arteaga, Miren; Beristain, Xabier; Navascués, Ana; Ongay, Eva; Castilla, Jesús

2017-02-01

In 2014, an autochthonous case of introduced malaria caused by Plasmodium vivax was identified in Spain. The strain that infected this patient was identical to that of a prior imported case from Pakistan. This is the first case where the source of infection could be identified since elimination in Spain.

Isotopic reconstruction of the weaning process in the archaeological population of Canímar Abajo, Cuba: A Bayesian probability mixing model approach

PubMed Central

Roksandic, Mirjana; Nikitović, Dejana; Rodríguez Suárez, Roberto; Smith, David; Kanik, Nadine; García Jordá, Dailys; Buhay, William M.

2017-01-01

The general lack of well-preserved juvenile skeletal remains from Caribbean archaeological sites has, in the past, prevented evaluations of juvenile dietary changes. Canímar Abajo (Cuba), with a large number of well-preserved juvenile and adult skeletal remains, provided a unique opportunity to fully assess juvenile paleodiets from an ancient Caribbean population. Ages for the start and the end of weaning and possible food sources used for weaning were inferred by combining the results of two Bayesian probability models that help to reduce some of the uncertainties inherent to bone collagen isotope based paleodiet reconstructions. Bone collagen (31 juveniles, 18 adult females) was used for carbon and nitrogen isotope analyses. The isotope results were assessed using two Bayesian probability models: Weaning Ages Reconstruction with Nitrogen isotopes and Stable Isotope Analyses in R. Breast milk seems to have been the most important protein source until two years of age with some supplementary food such as tropical fruits and root cultigens likely introduced earlier. After two, juvenile diets were likely continuously supplemented by starch rich foods such as root cultigens and legumes. By the age of three, the model results suggest that the weaning process was completed. Additional indications suggest that animal marine/riverine protein and maize, while part of the Canímar Abajo female diets, were likely not used to supplement juvenile diets. The combined use of both models here provided a more complete assessment of the weaning process for an ancient Caribbean population, indicating not only the start and end ages of weaning but also the relative importance of different food sources for different age juveniles. PMID:28459816

Isotopic reconstruction of the weaning process in the archaeological population of Canímar Abajo, Cuba: A Bayesian probability mixing model approach.

PubMed

Chinique de Armas, Yadira; Roksandic, Mirjana; Nikitović, Dejana; Rodríguez Suárez, Roberto; Smith, David; Kanik, Nadine; García Jordá, Dailys; Buhay, William M

2017-01-01

The general lack of well-preserved juvenile skeletal remains from Caribbean archaeological sites has, in the past, prevented evaluations of juvenile dietary changes. Canímar Abajo (Cuba), with a large number of well-preserved juvenile and adult skeletal remains, provided a unique opportunity to fully assess juvenile paleodiets from an ancient Caribbean population. Ages for the start and the end of weaning and possible food sources used for weaning were inferred by combining the results of two Bayesian probability models that help to reduce some of the uncertainties inherent to bone collagen isotope based paleodiet reconstructions. Bone collagen (31 juveniles, 18 adult females) was used for carbon and nitrogen isotope analyses. The isotope results were assessed using two Bayesian probability models: Weaning Ages Reconstruction with Nitrogen isotopes and Stable Isotope Analyses in R. Breast milk seems to have been the most important protein source until two years of age with some supplementary food such as tropical fruits and root cultigens likely introduced earlier. After two, juvenile diets were likely continuously supplemented by starch rich foods such as root cultigens and legumes. By the age of three, the model results suggest that the weaning process was completed. Additional indications suggest that animal marine/riverine protein and maize, while part of the Canímar Abajo female diets, were likely not used to supplement juvenile diets. The combined use of both models here provided a more complete assessment of the weaning process for an ancient Caribbean population, indicating not only the start and end ages of weaning but also the relative importance of different food sources for different age juveniles.

Genetic Diversity in Introduced Populations with an Allee Effect

PubMed Central

Wittmann, Meike J.; Gabriel, Wilfried; Metzler, Dirk

2014-01-01

A phenomenon that strongly influences the demography of small introduced populations and thereby potentially their genetic diversity is the demographic Allee effect, a reduction in population growth rates at small population sizes. We take a stochastic modeling approach to investigate levels of genetic diversity in populations that successfully overcame either a strong Allee effect, in which populations smaller than a certain critical size are expected to decline, or a weak Allee effect, in which the population growth rate is reduced at small sizes but not negative. Our results indicate that compared to successful populations without an Allee effect, successful populations with a strong Allee effect tend to (1) derive from larger founder population sizes and thus have a higher initial amount of genetic variation, (2) spend fewer generations at small population sizes where genetic drift is particularly strong, and (3) spend more time around the critical population size and thus experience more genetic drift there. In the case of multiple introduction events, there is an additional increase in diversity because Allee-effect populations tend to derive from a larger number of introduction events than other populations. Altogether, a strong Allee effect can either increase or decrease genetic diversity, depending on the average founder population size. By contrast, a weak Allee effect tends to decrease genetic diversity across the entire range of founder population sizes. Finally, we show that it is possible in principle to infer critical population sizes from genetic data, although this would require information from many independently introduced populations. PMID:25009147

Prostate-Specific Antigen (PSA)–Based Population Screening for Prostate Cancer: An Economic Analysis

PubMed Central

Tawfik, A

2015-01-01

Background The prostate-specific antigen (PSA) blood test has become widely used in Canada to test for prostate cancer (PC), the most common cancer among Canadian men. Data suggest that population-based PSA screening may not improve overall survival. Objectives This analysis aimed to review existing economic evaluations of population-based PSA screening, determine current spending on opportunistic PSA screening in Ontario, and estimate the cost of introducing a population-based PSA screening program in the province. Methods A systematic literature search was performed to identify economic evaluations of population-based PSA screening strategies published from 1998 to 2013. Studies were assessed for their methodological quality and applicability to the Ontario setting. An original cost analysis was also performed, using data from Ontario administrative sources and from the published literature. One-year costs were estimated for 4 strategies: no screening, current (opportunistic) screening of men aged 40 years and older, current (opportunistic) screening of men aged 50 to 74 years, and population-based screening of men aged 50 to 74 years. The analysis was conducted from the payer perspective. Results The literature review demonstrated that, overall, population-based PSA screening is costly and cost-ineffective but may be cost-effective in specific populations. Only 1 Canadian study, published 15 years ago, was identified. Approximately $119.2 million is being spent annually on PSA screening of men aged 40 years and older in Ontario, including close to $22 million to screen men younger than 50 and older than 74 years of age (i.e., outside the target age range for a population-based program). A population-based screening program in Ontario would cost approximately $149.4 million in the first year. Limitations Estimates were based on the synthesis of data from a variety of sources, requiring several assumptions and causing uncertainty in the results. For example, where Ontario-specific data were unavailable, data from the United States were used. Conclusions PSA screening is associated with significant costs to the health care system when the cost of the PSA test itself is considered in addition to the costs of diagnosis, staging, and treatment of screen-detected PCs. PMID:26366237

An Exercise to Introduce Power

ERIC Educational Resources Information Center

Seier, Edith; Liu, Yali

2013-01-01

In introductory statistics courses, the concept of power is usually presented in the context of testing hypotheses about the population mean. We instead propose an exercise that uses a binomial probability table to introduce the idea of power in the context of testing a population proportion. (Contains 2 tables, and 2 figures.)

Inferring evolutionary responses of Anolis carolinensis introduced into the Ogasawara archipelago using whole genome sequence data.

PubMed

Tamate, Satoshi; Iwasaki, Watal M; Krysko, Kenneth L; Camposano, Brian J; Mori, Hideaki; Funayama, Ryo; Nakayama, Keiko; Makino, Takashi; Kawata, Masakado

2017-12-21

Invaded species often can rapidly expand and establish in novel environments through adaptive evolution, resulting in devastating effects on native communities. However, it is unclear if genetic variation at whole-genomic levels is actually reduced in the introduced populations and which genetic changes have occurred responding to adaptation to new environments. In the 1960s, Anolis carolinensis was introduced onto one of the Ogasawara Islands, Japan, and subsequently expanded its range rapidly throughout two of the islands. Morphological comparison showed that lower hindlimb length in the introduced populations tended to be longer than those in its native Florida populations. Using re-sequenced whole genomic data, we estimated that the effective population size at the time of introduction was actually small (less than 50). We also inferred putative genomic regions subject to natural selection after this introduction event using SweeD and a method based on Tajima's D, π and F ST . Five candidate genes that were potentially subject to selection were estimated by both methods. The results suggest that there were standing variations that could potentially contribute to adaptation to nonnative environments despite the founder population being small.

Rainbow trout (Oncorhynchus mykiss) invasion and the spread of hybridization with native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

USGS Publications Warehouse

Boyer, M.C.; Muhlfeld, C.C.; Allendorf, F.W.

2008-01-01

We analyzed 13 microsatellite loci to estimate gene flow among westslope cutthroat trout, Oncorhynchus clarkii lewisi, populations and determine the invasion pattern of hybrids between native O. c. lewisi and introduced rainbow trout, Oncorhynchus mykiss, in streams of the upper Flathead River system, Montana (USA) and British Columbia (Canada). Fourteen of 31 sites lacked evidence of O. mykiss introgression, and gene flow among these nonhybridized O. c. lewisi populations was low, as indicated by significant allele frequency divergence among populations (?ST = 0.076, ?ST = 0.094, P < 0.001). Among hybridized sites, O. mykiss admixture declined with upstream distance from a site containing a hybrid swarm with a predominant (92%) O. mykiss genetic contribution. The spatial distribution of hybrid genotypes at seven diagnostic microsatellite loci revealed that O. mykiss invasion is facilitated by both long distance dispersal from this hybrid swarm and stepping-stone dispersal between hybridized populations. This study provides an example of how increased straying rates in the invasive taxon can contribute to the spread of extinction by hybridization and suggests that eradicating sources of introgression may be a useful conservation strategy for protecting species threatened with genomic extinction. ?? 2008 NRC.

Using Approximate Bayesian Computation to Probe Multiple Transiting Planet Systems

NASA Astrophysics Data System (ADS)

Morehead, Robert C.

2015-08-01

The large number of multiple transiting planet systems (MTPS) uncovered with Kepler suggest a population of well-aligned planetary systems. Previously, the distribution of transit duration ratios in MTPSs has been used to place constraints on the distributions of mutual orbital inclinations and orbital eccentricities in these systems. However, degeneracies with the underlying number of planets in these systems pose added challenges and make explicit likelihood functions intractable. Approximate Bayesian computation (ABC) offers an intriguing path forward. In its simplest form, ABC proposes from a prior on the population parameters to produce synthetic datasets via a physically-motivated model. Samples are accepted or rejected based on how close they come to reproducing the actual observed dataset to some tolerance. The accepted samples then form a robust and useful approximation of the true posterior distribution of the underlying population parameters. We will demonstrate the utility of ABC in exoplanet populations by presenting new constraints on the mutual inclination and eccentricity distributions in the Kepler MTPSs. We will also introduce Simple-ABC, a new open-source Python package designed for ease of use and rapid specification of general models, suitable for use in a wide variety of applications in both exoplanet science and astrophysics as a whole.

Spatial Dynamics of Human-Origin H1 Influenza A Virus in North American Swine

PubMed Central

Nelson, Martha I.; Lemey, Philippe; Tan, Yi; Vincent, Amy; Lam, Tommy Tsan-Yuk; Detmer, Susan; Viboud, Cécile; Suchard, Marc A.; Rambaut, Andrew; Holmes, Edward C.; Gramer, Marie

2011-01-01

The emergence and rapid global spread of the swine-origin H1N1/09 pandemic influenza A virus in humans underscores the importance of swine populations as reservoirs for genetically diverse influenza viruses with the potential to infect humans. However, despite their significance for animal and human health, relatively little is known about the phylogeography of swine influenza viruses in the United States. This study utilizes an expansive data set of hemagglutinin (HA1) sequences (n = 1516) from swine influenza viruses collected in North America during the period 2003–2010. With these data we investigate the spatial dissemination of a novel influenza virus of the H1 subtype that was introduced into the North American swine population via two separate human-to-swine transmission events around 2003. Bayesian phylogeographic analysis reveals that the spatial dissemination of this influenza virus in the US swine population follows long-distance swine movements from the Southern US to the Midwest, a corn-rich commercial center that imports millions of swine annually. Hence, multiple genetically diverse influenza viruses are introduced and co-circulate in the Midwest, providing the opportunity for genomic reassortment. Overall, the Midwest serves primarily as an ecological sink for swine influenza in the US, with sources of virus genetic diversity instead located in the Southeast (mainly North Carolina) and South-central (mainly Oklahoma) regions. Understanding the importance of long-distance pig transportation in the evolution and spatial dissemination of the influenza virus in swine may inform future strategies for the surveillance and control of influenza, and perhaps other swine pathogens. PMID:21695237

40 CFR 125.57 - Law governing issuance of a section 301(h) modified permit.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the discharge of any pollutant from a publicly owned treatment works into marine waters, if the... pretreatment requirements for sources introducing waste into such treatment works will be enforced; (6) In the... pretreatment requirement in effect, sources introducing waste into such works are in compliance with all...

Demographic consequences of inbreeding and outbreeding in Arnica montana: A field experiment

USGS Publications Warehouse

Luijten, S.H.; Kery, M.; Oostermeijer, J.G.B.; Den, Nijs H.J.C.M.

2002-01-01

1. The genetic constitution of populations may significantly affect demography. Founder populations or isolated remnants may show inbreeding depression, while established populations can be strongly adapted to the local environment. Gene exchange between populations can lead to better performance if heterozygosity levels are restored (heterosis), or to reduced performance if coadapted gene complexes are disrupted (outbreeding depression). 2. Five populations of the self-incompatible perennial Arnica montana (Asteraceae) were analysed for the demographic consequences of inbreeding and of intra- and interpopulation outcrossing, using both small and large populations as donors for the latter. We analysed seed production and seed weight and monitored growth, survival and flowering of offspring introduced as seeds and as 4-week-old seedlings in a 4-year field experiment. 3. Reduced seed set after selfing was probably due to the self-incompatibility system rather than to inbreeding depression. There was a significant increase for seed set after interpopulation crosses, which resulted from the alleviation of low mate availability in one of the small populations. 4. Significant inbreeding depression was observed for growth rates of plants introduced as seedlings. We found significant heterosis for flowering probability of plants introduced as seeds, but for plants introduced as seedlings, heterosis for seedling size and flowering probability was only marginally significant. Outbreeding depression was not observed. 5. The results of this study are important for reinforcement measures in small, remnant populations. Significant differences among populations for all measured fitness components suggest that reinforcement is best achieved using material from several populations. 6. The observed higher survival of seedlings as compared with seeds suggests that it is better to plant individuals than to sow. Sowing, however, is easier and cheaper, and was more likely to eliminate poorly adapted genotypes before they contribute to the next generation.

Meta-analysis reveals evolution in invasive plant species but little support for Evolution of Increased Competitive Ability (EICA).

PubMed

Felker-Quinn, Emmi; Schweitzer, Jennifer A; Bailey, Joseph K

2013-03-01

Ecological explanations for the success and persistence of invasive species vastly outnumber evolutionary hypotheses, yet evolution is a fundamental process in the success of any species. The Evolution of Increased Competitive Ability (EICA) hypothesis (Blossey and Nötzold 1995) proposes that evolutionary change in response to release from coevolved herbivores is responsible for the success of many invasive plant species. Studies that evaluate this hypothesis have used different approaches to test whether invasive populations allocate fewer resources to defense and more to growth and competitive ability than do source populations, with mixed results. We conducted a meta-analysis of experimental tests of evolutionary change in the context of EICA. In contrast to previous reviews, there was no support across invasive species for EICA's predictions regarding defense or competitive ability, although invasive populations were more productive than conspecific native populations under noncompetitive conditions. We found broad support for genetically based changes in defense and competitive plant traits after introduction into new ranges, but not in the manner suggested by EICA. This review suggests that evolution occurs as a result of plant introduction and population expansion in invasive plant species, and may contribute to the invasiveness and persistence of some introduced species.

Meta-analysis reveals evolution in invasive plant species but little support for Evolution of Increased Competitive Ability (EICA)

PubMed Central

Felker-Quinn, Emmi; Schweitzer, Jennifer A; Bailey, Joseph K

2013-01-01

Ecological explanations for the success and persistence of invasive species vastly outnumber evolutionary hypotheses, yet evolution is a fundamental process in the success of any species. The Evolution of Increased Competitive Ability (EICA) hypothesis (Blossey and Nötzold 1995) proposes that evolutionary change in response to release from coevolved herbivores is responsible for the success of many invasive plant species. Studies that evaluate this hypothesis have used different approaches to test whether invasive populations allocate fewer resources to defense and more to growth and competitive ability than do source populations, with mixed results. We conducted a meta-analysis of experimental tests of evolutionary change in the context of EICA. In contrast to previous reviews, there was no support across invasive species for EICA's predictions regarding defense or competitive ability, although invasive populations were more productive than conspecific native populations under noncompetitive conditions. We found broad support for genetically based changes in defense and competitive plant traits after introduction into new ranges, but not in the manner suggested by EICA. This review suggests that evolution occurs as a result of plant introduction and population expansion in invasive plant species, and may contribute to the invasiveness and persistence of some introduced species. PMID:23531703

The effects of restricted glycolysis on stem-cell like characteristics of breast cancer cells

PubMed Central

Banerjee, Arindam; Arvinrad, Pardis; Darley, Matthew; Laversin, Stéphanie A.; Parker, Rachel; Rose-Zerilli, Matthew J.J.; Townsend, Paul A.; Cutress, Ramsey I.; Beers, Stephen A.; Houghton, Franchesca D.; Birts, Charles N.; Blaydes, Jeremy P.

2018-01-01

Altered glycolysis is a characteristic of many cancers, and can also be associated with changes in stem cell-like cancer (SCLC) cell populations. We therefore set out to directly examine the effect of glycolysis on SCLC cell phenotype, using a model where glycolysis is stably reduced by adapting the cells to a sugar source other than glucose. Restricting glycolysis using this approach consistently resulted in cells with increased oncogenic potential; including an increase in SCLC cells, proliferation in 3D matrigel, invasiveness, chemoresistance, and altered global gene expression. Tumorigenicity in vivo was also markedly increased. SCLC cells exhibited increased dependence upon alternate metabolic pathways. They also became c-KIT dependent, indicating that their apparent state of maturation is regulated by glycolysis. Single-cell mRNA sequencing identified altered networks of metabolic-, stem- and signaling- gene expression within SCLC-enriched populations in response to glycolytic restriction. Therefore, reduced glycolysis, which may occur in niches within tumors where glucose availability is limiting, can promote tumor aggressiveness by increasing SCLC cell populations, but can also introduce novel, potentially exploitable, vulnerabilities in SCLC cells. PMID:29796188

Avoidance response of juvenile Pacific treefrogs to chemical cues of introduced predatory bullfrogs.

PubMed

Chivers, D P; Wildy, E L; Kiesecker, J M; Blaustein, A R

2001-08-01

Bullfrogs (Rana catesbeiana), native to eastern North America, were introduced into Oregon in the 1930's. Bullfrogs are highly efficient predators that are known to eat a variety of prey including other amphibians. In laboratory experiments, we investigated whether juvenile Pacific treefrogs (Hyla regilla) recognize adult bullfrogs as a predatory threat. The ability of prey animals to acquire recognition of an introduced predator has important implications for survival of the prey. We found that treefrogs from a population that co-occurred with bullfrogs showed a strong avoidance of chemical cues of bullfrogs. In contrast, treefrogs from a population that did not co-occur with bullfrogs, did not respond to the bullfrog cues. Additional experiments showed that both populations of treefrogs use chemical cues to mediate predation risk. Treefrogs from both populations avoided chemical alarm cues from injured conspecifics.

40 CFR 411.26 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS CEMENT MANUFACTURING POINT SOURCE CATEGORY Leaching Subcategory § 411.26 Pretreatment standards for new sources. Any new source subject to this subpart that introduces process...

EdVentures in Population Education. Teacher's Guide.

ERIC Educational Resources Information Center

Zero Population Growth, Inc., Washington, DC.

This kit contains 16 comprehensive activity modules that elementary and secondary teachers can use to introduce students to a wide range of population trends. The modules may also be used to introduce these trends to citizens in the community. Each module includes: (1) recommended educational level; (2) curriculum area (science, social studies,…

Shift in cytotype frequency and niche space in the invasive plant Centaurea maculosa.

PubMed

Treier, Urs A; Broennimann, Olivier; Normand, Signe; Guisan, Antoine; Schaffner, Urs; Steinger, Thomas; Müller-Schärer, Heinz

2009-05-01

Polyploidy is often assumed to increase the spread and thus the success of alien plant species, but few empirical studies exist. We tested this hypothesis with Centaurea maculosa Lam., a species native to Europe and introduced into North America approximately 120 years ago where it became highly invasive. We analyzed the ploidy level of more than 2000 plants from 93 native and 48 invasive C. maculosa populations and found a pronounced shift in the relative frequency of diploid and tetraploid cytotypes. In Europe diploid populations occur in higher frequencies than tetraploids and only four populations had both cytotypes, while in North America diploid plants were found in only one mixed population and thus tetraploids clearly dominated. Our results showed a pronounced shift in the climatic niche between tetraploid populations in the native and introduced range toward drier climate in North America and a similar albeit smaller shift between diploids and tetraploids in the native range. The field data indicate that diploids have a predominately monocarpic life cycle, while tetraploids are often polycarpic. Additionally, the polycarpic life-form seems to be more prevalent among tetraploids in the introduced range than among tetraploids in the native range. Our study suggests that both ploidy types of C. maculosa were introduced into North America, but tetraploids became the dominant cytotype with invasion. We suggest that the invasive success of C. maculosa is partly due to preadaptation of the tetraploid cytotype in Europe to drier climate and possibly further adaptation to these conditions in the introduced range. The potential for earlier and longer seed production associated with the polycarpic life cycle constitutes an additional factor that may have led to the dominance of tetraploids over diploids in the introduced range.

Identifying the institutional decision process to introduce decentralized sanitation in the city of Kunming (China).

PubMed

Medilanski, Edi; Chuan, Liang; Mosler, Hans-Joachim; Schertenleib, Roland; Larsen, Tove A

2007-05-01

We conducted a study of the institutional barriers to introducing urine source separation in the urban area of Kunming, China. On the basis of a stakeholder analysis, we constructed stakeholder diagrams showing the relative importance of decision-making power and (positive) interest in the topic. A hypothetical decision-making process for the urban case was derived based on a successful pilot project in a periurban area. All our results were evaluated by the stakeholders. We concluded that although a number of primary stakeholders have a large interest in testing urine source separation also in an urban context, most of the key stakeholders would be reluctant to this idea. However, the success in the periurban area showed that even a single, well-received pilot project can trigger the process of broad dissemination of new technologies. Whereas the institutional setting for such a pilot project is favorable in Kunming, a major challenge will be to adapt the technology to the demands of an urban population. Methodologically, we developed an approach to corroborate a stakeholder analysis with the perception of the stakeholders themselves. This is important not only in order to validate the analysis but also to bridge the theoretical gap between stakeholder analysis and stakeholder involvement. We also show that in disagreement with the assumption of most policy theories, local stakeholders consider informal decision pathways to be of great importance in actual policy-making.

Identifying the Institutional Decision Process to Introduce Decentralized Sanitation in the City of Kunming (China)

NASA Astrophysics Data System (ADS)

Medilanski, Edi; Chuan, Liang; Mosler, Hans-Joachim; Schertenleib, Roland; Larsen, Tove A.

2007-05-01

We conducted a study of the institutional barriers to introducing urine source separation in the urban area of Kunming, China. On the basis of a stakeholder analysis, we constructed stakeholder diagrams showing the relative importance of decision-making power and (positive) interest in the topic. A hypothetical decision-making process for the urban case was derived based on a successful pilot project in a periurban area. All our results were evaluated by the stakeholders. We concluded that although a number of primary stakeholders have a large interest in testing urine source separation also in an urban context, most of the key stakeholders would be reluctant to this idea. However, the success in the periurban area showed that even a single, well-received pilot project can trigger the process of broad dissemination of new technologies. Whereas the institutional setting for such a pilot project is favorable in Kunming, a major challenge will be to adapt the technology to the demands of an urban population. Methodologically, we developed an approach to corroborate a stakeholder analysis with the perception of the stakeholders themselves. This is important not only in order to validate the analysis but also to bridge the theoretical gap between stakeholder analysis and stakeholder involvement. We also show that in disagreement with the assumption of most policy theories, local stakeholders consider informal decision pathways to be of great importance in actual policy-making.

Identifying currents in the gene pool for bacterial populations using an integrative approach.

PubMed

Tang, Jing; Hanage, William P; Fraser, Christophe; Corander, Jukka

2009-08-01

The evolution of bacterial populations has recently become considerably better understood due to large-scale sequencing of population samples. It has become clear that DNA sequences from a multitude of genes, as well as a broad sample coverage of a target population, are needed to obtain a relatively unbiased view of its genetic structure and the patterns of ancestry connected to the strains. However, the traditional statistical methods for evolutionary inference, such as phylogenetic analysis, are associated with several difficulties under such an extensive sampling scenario, in particular when a considerable amount of recombination is anticipated to have taken place. To meet the needs of large-scale analyses of population structure for bacteria, we introduce here several statistical tools for the detection and representation of recombination between populations. Also, we introduce a model-based description of the shape of a population in sequence space, in terms of its molecular variability and affinity towards other populations. Extensive real data from the genus Neisseria are utilized to demonstrate the potential of an approach where these population genetic tools are combined with an phylogenetic analysis. The statistical tools introduced here are freely available in BAPS 5.2 software, which can be downloaded from http://web.abo.fi/fak/mnf/mate/jc/software/baps.html.

Trophic ecology of introduced populations of Alaska blackfish (Dallia pectoralis) in the Cook Inlet Basin, Alaska.

PubMed

Eidam, Dona M; von Hippel, Frank A; Carlson, Matthew L; Lassuy, Dennis R; López, J Andrés

2016-07-01

Introduced non-native fishes have the potential to substantially alter aquatic ecology in the introduced range through competition and predation. The Alaska blackfish ( Dallia pectoralis ) is a freshwater fish endemic to Chukotka and Alaska north of the Alaska Range (Beringia); the species was introduced outside of its native range to the Cook Inlet Basin of Alaska in the 1950s, where it has since become widespread. Here we characterize the diet of Alaska blackfish at three Cook Inlet Basin sites, including a lake, a stream, and a wetland. We analyze stomach plus esophageal contents to assess potential impacts on native species via competition or predation. Alaska blackfish in the Cook Inlet Basin consume a wide range of prey, with major prey consisting of epiphytic/benthic dipteran larvae, gastropods, and ostracods. Diets of the introduced populations of Alaska blackfish are similar in composition to those of native juvenile salmonids and stickleback. Thus, Alaska blackfish may affect native fish populations via competition. Fish ranked third in prey importance for both lake and stream blackfish diets but were of minor importance for wetland blackfish.

Trophic ecology of introduced populations of Alaska blackfish (Dallia pectoralis) in the Cook Inlet Basin, Alaska

PubMed Central

Eidam, Dona M.; Carlson, Matthew L.; Lassuy, Dennis R.; López, J. Andrés

2016-01-01

Introduced non-native fishes have the potential to substantially alter aquatic ecology in the introduced range through competition and predation. The Alaska blackfish (Dallia pectoralis) is a freshwater fish endemic to Chukotka and Alaska north of the Alaska Range (Beringia); the species was introduced outside of its native range to the Cook Inlet Basin of Alaska in the 1950s, where it has since become widespread. Here we characterize the diet of Alaska blackfish at three Cook Inlet Basin sites, including a lake, a stream, and a wetland. We analyze stomach plus esophageal contents to assess potential impacts on native species via competition or predation. Alaska blackfish in the Cook Inlet Basin consume a wide range of prey, with major prey consisting of epiphytic/benthic dipteran larvae, gastropods, and ostracods. Diets of the introduced populations of Alaska blackfish are similar in composition to those of native juvenile salmonids and stickleback. Thus, Alaska blackfish may affect native fish populations via competition. Fish ranked third in prey importance for both lake and stream blackfish diets but were of minor importance for wetland blackfish. PMID:28082763

Patterns of ancestry and genetic diversity in reintroduced populations of the slimy sculpin: Implications for conservation

USGS Publications Warehouse

Huff, David D.; Miller, Loren M.; Vondracek, Bruce C.

2010-01-01

Reintroductions are a common approach for preserving intraspecific biodiversity in fragmented landscapes. However, they may exacerbate the reduction in genetic diversity initially caused by population fragmentation because the effective population size of reintroduced populations is often smaller and reintroduced populations also tend to be more geographically isolated than native populations. Mixing genetically divergent sources for reintroduction purposes is a practice intended to increase genetic diversity. We documented the outcome of reintroductions from three mixed sources on the ancestral composition and genetic variation of a North American fish, the slimy sculpin (Cottus cognatus). We used microsatellite markers to evaluate allelic richness and heterozygosity in the reintroduced populations relative to computer simulated expectations. Sculpins in reintroduced populations exhibited higher levels of heterozygosity and allelic richness than any single source, but only slightly higher than the single most genetically diverse source population. Simulations intended to mimic an ideal scenario for maximizing genetic variation in the reintroduced populations also predicted increases, but they were only moderately greater than the most variable source population. We found that a single source contributed more than the other two sources at most reintroduction sites. We urge caution when choosing whether to mix source populations in reintroduction programs. Genetic characteristics of candidate source populations should be evaluated prior to reintroduction if feasible. When combined with knowledge of the degree of genetic distinction among sources, simulations may allow the genetic diversity benefits of mixing populations to be weighed against the risks of outbreeding depression in reintroduced and nearby populations.

Patterns of ancestry and genetic diversity in reintroduced populations of the slimy sculpin: Implications for conservation

USGS Publications Warehouse

Huff, D.D.; Miller, L.M.; Vondracek, B.

2010-01-01

Reintroductions are a common approach for preserving intraspecific biodiversity in fragmented landscapes. However, they may exacerbate the reduction in genetic diversity initially caused by population fragmentation because the effective population size of reintroduced populations is often smaller and reintroduced populations also tend to be more geographically isolated than native populations. Mixing genetically divergent sources for reintroduction purposes is a practice intended to increase genetic diversity. We documented the outcome of reintroductions from three mixed sources on the ancestral composition and genetic variation of a North American fish, the slimy sculpin (Cottus cognatus). We used microsatellite markers to evaluate allelic richness and heterozygosity in the reintroduced populations relative to computer simulated expectations. Sculpins in reintroduced populations exhibited higher levels of heterozygosity and allelic richness than any single source, but only slightly higher than the single most genetically diverse source population. Simulations intended to mimic an ideal scenario for maximizing genetic variation in the reintroduced populations also predicted increases, but they were only moderately greater than the most variable source population. We found that a single source contributed more than the other two sources at most reintroduction sites. We urge caution when choosing whether to mix source populations in reintroduction programs. Genetic characteristics of candidate source populations should be evaluated prior to reintroduction if feasible. When combined with knowledge of the degree of genetic distinction among sources, simulations may allow the genetic diversity benefits of mixing populations to be weighed against the risks of outbreeding depression in reintroduced and nearby populations. ?? 2010 US Government.

The Impact of Library Tutorials on the Information Literacy Skills of Occupational Therapy and Physical Therapy Students in an Evidence-Based Practice Course: A Rubric Assessment.

PubMed

Schweikhard, April J; Hoberecht, Toni; Peterson, Alyssa; Randall, Ken

2018-01-01

This study measures how online library instructional tutorials implemented into an evidence-based practice course have impacted the information literacy skills of occupational and physical therapy graduate students. Through a rubric assessment of final course papers, this study compares differences in students' search strategies and cited sources pre- and post-implementation of the tutorials. The population includes 180 randomly selected graduate students from before and after the library tutorials were introduced into the course curriculum. Results indicate a statistically significant increase in components of students' searching skills and ability to find higher levels of evidence after completing the library tutorials.

Distributed data networks: a blueprint for Big Data sharing and healthcare analytics.

PubMed

Popovic, Jennifer R

2017-01-01

This paper defines the attributes of distributed data networks and outlines the data and analytic infrastructure needed to build and maintain a successful network. We use examples from one successful implementation of a large-scale, multisite, healthcare-related distributed data network, the U.S. Food and Drug Administration-sponsored Sentinel Initiative. Analytic infrastructure-development concepts are discussed from the perspective of promoting six pillars of analytic infrastructure: consistency, reusability, flexibility, scalability, transparency, and reproducibility. This paper also introduces one use case for machine learning algorithm development to fully utilize and advance the portfolio of population health analytics, particularly those using multisite administrative data sources. © 2016 New York Academy of Sciences.

A multidisciplinary database for global distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolfe, P.J.

The issue of selenium toxicity in the environment has been documented in the scientific literature for over 50 years. Recent studies reveal a complex connection between selenium and human and animal populations. This article introduces a bibliographic citation database on selenium in the environment developed for global distribution via the Internet by the University of Wyoming Libraries. The database incorporates material from commercial sources, print abstracts, indexes, and U.S. government literature, resulting in a multidisciplinary resource. Relevant disciplines include, biology, medicine, veterinary science, botany, chemistry, geology, pollution, aquatic sciences, ecology, and others. It covers the years 1985-1996 for most subjectmore » material, with additional years being added as resources permit.« less

On the selection of significant variables in a model for the deteriorating process of facades

NASA Astrophysics Data System (ADS)

Serrat, C.; Gibert, V.; Casas, J. R.; Rapinski, J.

2017-10-01

In previous works the authors of this paper have introduced a predictive system that uses survival analysis techniques for the study of time-to-failure in the facades of a building stock. The approach is population based, in order to obtain information on the evolution of the stock across time, and to help the manager in the decision making process on global maintenance strategies. For the decision making it is crutial to determine those covariates -like materials, morphology and characteristics of the facade, orientation or environmental conditions- that play a significative role in the progression of different failures. The proposed platform also incorporates an open source GIS plugin that includes survival and test moduli that allow the investigator to model the time until a lesion taking into account the variables collected during the inspection process. The aim of this paper is double: a) to shortly introduce the predictive system, as well as the inspection and the analysis methodologies and b) to introduce and illustrate the modeling strategy for the deteriorating process of an urban front. The illustration will be focused on the city of L’Hospitalet de Llobregat (Barcelona, Spain) in which more than 14,000 facades have been inspected and analyzed.

Transmission network of the 2014-2015 Ebola epidemic in Sierra Leone.

PubMed

Yang, Wan; Zhang, Wenyi; Kargbo, David; Yang, Ruifu; Chen, Yong; Chen, Zeliang; Kamara, Abdul; Kargbo, Brima; Kandula, Sasikiran; Karspeck, Alicia; Liu, Chao; Shaman, Jeffrey

2015-11-06

Understanding the growth and spatial expansion of (re)emerging infectious disease outbreaks, such as Ebola and avian influenza, is critical for the effective planning of control measures; however, such efforts are often compromised by data insufficiencies and observational errors. Here, we develop a spatial-temporal inference methodology using a modified network model in conjunction with the ensemble adjustment Kalman filter, a Bayesian inference method equipped to handle observational errors. The combined method is capable of revealing the spatial-temporal progression of infectious disease, while requiring only limited, readily compiled data. We use this method to reconstruct the transmission network of the 2014-2015 Ebola epidemic in Sierra Leone and identify source and sink regions. Our inference suggests that, in Sierra Leone, transmission within the network introduced Ebola to neighbouring districts and initiated self-sustaining local epidemics; two of the more populous and connected districts, Kenema and Port Loko, facilitated two independent transmission pathways. Epidemic intensity differed by district, was highly correlated with population size (r = 0.76, p = 0.0015) and a critical window of opportunity for containing local Ebola epidemics at the source (ca one month) existed. This novel methodology can be used to help identify and contain the spatial expansion of future (re)emerging infectious disease outbreaks. © 2015 The Author(s).

Sequence-based analysis of the microbial composition of water kefir from multiple sources.

PubMed

Marsh, Alan J; O'Sullivan, Orla; Hill, Colin; Ross, R Paul; Cotter, Paul D

2013-11-01

Water kefir is a water-sucrose-based beverage, fermented by a symbiosis of bacteria and yeast to produce a final product that is lightly carbonated, acidic and that has a low alcohol percentage. The microorganisms present in water kefir are introduced via water kefir grains, which consist of a polysaccharide matrix in which the microorganisms are embedded. We aimed to provide a comprehensive sequencing-based analysis of the bacterial population of water kefir beverages and grains, while providing an initial insight into the corresponding fungal population. To facilitate this objective, four water kefirs were sourced from the UK, Canada and the United States. Culture-independent, high-throughput, sequencing-based analyses revealed that the bacterial fraction of each water kefir and grain was dominated by Zymomonas, an ethanol-producing bacterium, which has not previously been detected at such a scale. The other genera detected were representatives of the lactic acid bacteria and acetic acid bacteria. Our analysis of the fungal component established that it was comprised of the genera Dekkera, Hanseniaspora, Saccharomyces, Zygosaccharomyces, Torulaspora and Lachancea. This information will assist in the ultimate identification of the microorganisms responsible for the potentially health-promoting attributes of these beverages. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Online market research panel members as controls in case-control studies to investigate gastrointestinal disease outbreaks: early experiences and lessons learnt from the UK.

PubMed

Mook, P; McCormick, J; Kanagarajah, S; Adak, G K; Cleary, P; Elson, R; Gobin, M; Hawker, J; Inns, T; Sinclair, C; Trienekens, S C M; Vivancos, R; McCarthy, N D

2018-03-01

Established methods of recruiting population controls for case-control studies to investigate gastrointestinal disease outbreaks can be time consuming, resulting in delays in identifying the source or vehicle of infection. After an initial evaluation of using online market research panel members as controls in a case-control study to investigate a Salmonella outbreak in 2013, this method was applied in four further studies in the UK between 2014 and 2016. We used data from all five studies and interviews with members of each outbreak control team and market research panel provider to review operational issues, evaluate risk of bias in this approach and consider methods to reduce confounding and bias. The investigators of each outbreak reported likely time and cost savings from using market research controls. There were systematic differences between case and control groups in some studies but no evidence that conclusions on the likely source or vehicle of infection were incorrect. Potential selection biases introduced by using this sampling frame and the low response rate are unclear. Methods that might reduce confounding and some bias should be balanced with concerns for overmatching. Further evaluation of this approach using comparisons with traditional methods and population-based exposure survey data is recommended.

Invasive hybridization in a threatened species is accelerated by climate change

NASA Astrophysics Data System (ADS)

Muhlfeld, Clint C.; Kovach, Ryan P.; Jones, Leslie A.; Al-Chokhachy, Robert; Boyer, Matthew C.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Allendorf, Fred W.

2014-07-01

Climate change will decrease worldwide biodiversity through a number of potential pathways, including invasive hybridization (cross-breeding between invasive and native species). How climate warming influences the spread of hybridization and loss of native genomes poses difficult ecological and evolutionary questions with little empirical information to guide conservation management decisions. Here we combine long-term genetic monitoring data with high-resolution climate and stream temperature predictions to evaluate how recent climate warming has influenced the spatio-temporal spread of human-mediated hybridization between threatened native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and non-native rainbow trout (Oncorhynchus mykiss), the world's most widely introduced invasive fish. Despite widespread release of millions of rainbow trout over the past century within the Flathead River system, a large relatively pristine watershed in western North America, historical samples revealed that hybridization was prevalent only in one (source) population. During a subsequent 30-year period of accelerated warming, hybridization spread rapidly and was strongly linked to interactions between climatic drivers--precipitation and temperature--and distance to the source population. Specifically, decreases in spring precipitation and increases in summer stream temperature probably promoted upstream expansion of hybridization throughout the system. This study shows that rapid climate warming can exacerbate interactions between native and non-native species through invasive hybridization, which could spell genomic extinction for many species.

Genetic divergence in the small Indian mongoose (Herpestes auropunctatus), a widely distributed invasive species.

PubMed

Thulin, Carl-Gustaf; Simberloff, Daniel; Barun, Arijana; McCracken, Gary; Pascal, Michel; Islam, M Anwarul

2006-11-01

The combination of founder events, random drift and new selective forces experienced by introduced species typically lowers genetic variation and induces differentiation from the ancestral population. Here, we investigate microsatellite differentiation between introduced and native populations of the small Indian mongoose (Herpestes auropunctatus). Many expectations based on introduction history, such as loss of alleles and relationships among populations, are confirmed. Nevertheless, when applying population assignment methods to our data, we observe a few specimens that are incorrectly assigned and/or appear to have a mixed ancestry, despite estimates of substantial population differentiation. Thus, we suggest that population assignments of individuals should be viewed as tentative and that there should be agreement among different algorithms before assignments are applied in conservation or management. Further, we find no congruence between previously reported morphological differentiation and the sorting of microsatellite variation. Some introduced populations have retained much genetic variation while others have not, irrespective of morphology. Finally, we find alleles from the sympatric grey mongoose (Herpestes edwardsii) in one small Indian mongoose within the native range, suggesting an alternative explanation for morphological differentiation involving a shift in female preferences in allopatry.

Evaluating Web Sources in an EAP Course: Introducing a Multi-Trait Instrument for Feedback and Assessment

ERIC Educational Resources Information Center

Stapleton, Paul; Helms-Park, Rena

2006-01-01

This paper introduces the Website Acceptability Tiered Checklist (WATCH), a preliminary version of a multi-trait scale that could be used by instructors and students to assess the quality of websites chosen as source materials in students' research papers in a Humanities program. The scale includes bands for assessing: (i) the authority and…

40 CFR 421.65 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Copper... existing sources. The mass of wastewater pollutants in secondary copper process wastewater introduced into...

40 CFR 421.65 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Copper... existing sources. The mass of wastewater pollutants in secondary copper process wastewater introduced into...

A model describing the effect of sex-reversed YY fish in an established wild population: The use of a Trojan Y chromosome to cause extinction of an introduced exotic species.

PubMed

Gutierrez, Juan B; Teem, John L

2006-07-21

A novel means of inducing extinction of an exotic fish population is proposed using a genetic approach to shift the ratio of male to females within a population. In the proposed strategy, sex-reversed fish containing two Y chromosomes are introduced into a normal fish population. These YY fish result in the production of a disproportionate number of male fish in subsequent generations. Mathematical modeling of the system following introduction of YY fish at a constant rate reveals that female fish decline in numbers over time, leading to eventual extinction of the population.

Two colonisation stages generate two different patterns of genetic diversity within native and invasive ranges of Ulex europaeus

PubMed Central

Hornoy, B; Atlan, A; Roussel, V; Buckley, Y M; Tarayre, M

2013-01-01

Genetic diversity and the way a species is introduced influence the capacity of populations of invasive species to persist in, and adapt to, their new environment. The diversity of introduced populations affects their evolutionary potential, which is particularly important for species that have invaded a wide range of habitats and climates, such as European gorse, Ulex europaeus. This species originated in the Iberian peninsula and colonised Europe in the Neolithic; over the course of the past two centuries it was introduced to, and has become invasive in, other continents. We characterised neutral genetic diversity and its structure in the native range and in invaded regions. By coupling these results with historical data, we have identified the way in which gorse populations were introduced and the consequences of introduction history on genetic diversity. Our study is based on the genotyping of individuals from 18 populations at six microsatellite loci. As U. europaeus is an allohexaploid species, we used recently developed tools that take into account genotypic ambiguity. Our results show that genetic diversity in gorse is very high and mainly contained within populations. We confirm that colonisation occurred in two stages. During the first stage, gorse spread out naturally from Spain towards northern Europe, losing some genetic diversity. During the second stage, gorse was introduced by humans into different regions of the world, from northern Europe. These introductions resulted in the loss of rare alleles but did not significantly reduce genetic diversity and thus the evolutionary potential of this invasive species. PMID:23759725

Two colonisation stages generate two different patterns of genetic diversity within native and invasive ranges of Ulex europaeus.

PubMed

Hornoy, B; Atlan, A; Roussel, V; Buckley, Y M; Tarayre, M

2013-11-01

Genetic diversity and the way a species is introduced influence the capacity of populations of invasive species to persist in, and adapt to, their new environment. The diversity of introduced populations affects their evolutionary potential, which is particularly important for species that have invaded a wide range of habitats and climates, such as European gorse, Ulex europaeus. This species originated in the Iberian peninsula and colonised Europe in the Neolithic; over the course of the past two centuries it was introduced to, and has become invasive in, other continents. We characterised neutral genetic diversity and its structure in the native range and in invaded regions. By coupling these results with historical data, we have identified the way in which gorse populations were introduced and the consequences of introduction history on genetic diversity. Our study is based on the genotyping of individuals from 18 populations at six microsatellite loci. As U. europaeus is an allohexaploid species, we used recently developed tools that take into account genotypic ambiguity. Our results show that genetic diversity in gorse is very high and mainly contained within populations. We confirm that colonisation occurred in two stages. During the first stage, gorse spread out naturally from Spain towards northern Europe, losing some genetic diversity. During the second stage, gorse was introduced by humans into different regions of the world, from northern Europe. These introductions resulted in the loss of rare alleles but did not significantly reduce genetic diversity and thus the evolutionary potential of this invasive species.

Can invasions occur without change? A comparison of G-matrices and selection in the peach-potato aphid, Myzus persicae

PubMed Central

Bacigalupe, Leonardo D; Barrientos, Karin; Beckerman, Andrew P; Carter, Mauricio J; Figueroa, Christian C; Foster, Stephen P; Moore, Allen J; Silva, Andrea X; Nespolo, Roberto F

2013-01-01

Most evolutionary research on biological invasions has focused on changes seen between the native and invaded range for a particular species. However, it is likely that species that live in human-modified habitats in their native range might have evolved specific adaptations to those environments, which increase the likelihood of establishment and spread in similar human-altered environments. From a quantitative genetic perspective, this hypothesis suggests that both native and introduced populations should reside at or near the same adaptive peak. Therefore, we should observe no overall changes in the G (genetic variance–covariance) matrices between native and introduced ranges, and stabilizing selection on fitness-related traits in all populations. We tested these predictions comparing three populations of the worldwide pest Myzus persicae from the Middle East (native range) and the UK and Chile (separately introduced ranges). In general, our results provide mixed support for this idea, but further comparisons of other species are needed. In particular, we found that there has been some limited evolution in the studied traits, with the Middle East population differing from the UK and Chilean populations. This was reflected in the structure of the G-matrices, in which Chile differed from both UK and Middle East populations. Furthermore, the amount of genetic variation was massively reduced in Chile in comparison with UK and Middle East populations. Finally, we found no detectable selection on any trait in the three populations, but clones from the introduced ranges started to reproduce later, were smaller, had smaller offspring, and had lower reproductive fitness than clones from the native range. PMID:24455140

Contemporary evolution during invasion: evidence for differentiation, natural selection, and local adaptation.

PubMed

Colautti, Robert I; Lau, Jennifer A

2015-05-01

Biological invasions are 'natural' experiments that can improve our understanding of contemporary evolution. We evaluate evidence for population differentiation, natural selection and adaptive evolution of invading plants and animals at two nested spatial scales: (i) among introduced populations (ii) between native and introduced genotypes. Evolution during invasion is frequently inferred, but rarely confirmed as adaptive. In common garden studies, quantitative trait differentiation is only marginally lower (~3.5%) among introduced relative to native populations, despite genetic bottlenecks and shorter timescales (i.e. millennia vs. decades). However, differentiation between genotypes from the native vs. introduced range is less clear and confounded by nonrandom geographic sampling; simulations suggest this causes a high false-positive discovery rate (>50%) in geographically structured populations. Selection differentials (¦s¦) are stronger in introduced than in native species, although selection gradients (¦β¦) are not, consistent with introduced species experiencing weaker genetic constraints. This could facilitate rapid adaptation, but evidence is limited. For example, rapid phenotypic evolution often manifests as geographical clines, but simulations demonstrate that nonadaptive trait clines can evolve frequently during colonization (~two-thirds of simulations). Additionally, QST-FST studies may often misrepresent the strength and form of natural selection acting during invasion. Instead, classic approaches in evolutionary ecology (e.g. selection analysis, reciprocal transplant, artificial selection) are necessary to determine the frequency of adaptive evolution during invasion and its influence on establishment, spread and impact of invasive species. These studies are rare but crucial for managing biological invasions in the context of global change. © 2015 John Wiley & Sons Ltd.

Impacts of biological control and invasive species on a non-target native Hawaiian insect.

PubMed

Johnson, M Tracy; Follett, Peter A; Taylor, Andrew D; Jones, Vincent P

2005-02-01

The potential for classical biological control to cause unintended harm to native species was evaluated in the case of the endemic Hawaiian koa bug, Coleotichus blackburniae White (Hemiptera: Scutelleridae), and parasitoids introduced to Hawaii for control of an agricultural pest, the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae). Parasitism of C. blackburniae eggs, nymphs and adults by biocontrol agents was quantified across a wide range of habitats and compared to other sources of mortality. Egg mortality due to the biocontrol agent Trissolcus basalis Wollaston (Hymenoptera: Scelionidae) was low (maximum 26%) and confined to elevations below 500 m on a single host plant. Predation, mainly by alien spiders and ants, was the greatest source of egg mortality (maximum 87%). Parasitism of adult C. blackburniae by the biocontrol agent Trichopoda pilipes (F.) (Diptera: Tachinidae) was near zero at 21 of 24 sites surveyed. Three sites with high bug density had higher levels of T. pilipes parasitism, reaching maxima of 70% among adult female bugs, 100% among males and 50% among fifth instars. Male-biased parasitism indicated that T. pilipes is adapted to using male aggregation pheromone for finding C. blackburniae hosts. The relative impacts of biocontrol agents and other sources of mortality were compared using life tables. Invasive species, particularly generalist egg predators, had the greatest impacts on C. blackburniae populations. Effects of intentionally introduced parasitoids were relatively minor, although the tachinid T. pilipes showed potential for large impacts at individual sites. In retrospect, non-target attacks by biological control agents on C. blackburniae were predictable, but the environmental range and magnitude of impacts would have been difficult to foresee.

ON THE RADIO AND OPTICAL LUMINOSITY EVOLUTION OF QUASARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singal, J.; Petrosian, V.; Lawrence, A.

2011-12-20

We calculate simultaneously the radio and optical luminosity evolutions of quasars, and the distribution in radio loudness R defined as the ratio of radio and optical luminosities, using a flux-limited data set containing 636 quasars with radio and optical fluxes from White et al. We first note that when dealing with multi-variate data it is imperative to first determine the true correlations among the variables, not those introduced by the observational selection effects, before obtaining the individual distributions of the variables. We use the methods developed by Efron and Petrosian which are designed to obtain unbiased correlations, distributions, and evolutionmore » with redshift from a data set truncated due to observational biases. It is found that the population of quasars exhibits strong positive correlation between the radio and optical luminosities. With this correlation, whether intrinsic or observationally induced accounted for, we find that there is a strong luminosity evolution with redshift in both wavebands, with significantly higher radio than optical evolution. We conclude that the luminosity evolution obtained by arbitrarily separating the sources into radio-loud (R > 10) and radio-quiet (R < 10) populations introduces significant biases that skew the result considerably. We also construct the local radio and optical luminosity functions and the density evolution. Finally, we consider the distribution of the radio-loudness parameter R obtained from careful treatment of the selection effects and luminosity evolutions with that obtained from the raw data without such considerations. We find a significant difference between the two distributions and no clear sign of bi-modality in the true distribution for the range of R values considered. Our results indicate therefore, somewhat surprisingly, that there is no critical switch in the efficiency of the production of disk outflows/jets between very radio-quiet and very radio-loud quasars, but rather a smooth transition. Also, this efficiency seems higher for the high-redshift and more luminous sources in the sample considered.« less

High order statistical signatures from source-driven measurements of subcritical fissile systems

NASA Astrophysics Data System (ADS)

Mattingly, John Kelly

1998-11-01

This research focuses on the development and application of high order statistical analyses applied to measurements performed with subcritical fissile systems driven by an introduced neutron source. The signatures presented are derived from counting statistics of the introduced source and radiation detectors that observe the response of the fissile system. It is demonstrated that successively higher order counting statistics possess progressively higher sensitivity to reactivity. Consequently, these signatures are more sensitive to changes in the composition, fissile mass, and configuration of the fissile assembly. Furthermore, it is shown that these techniques are capable of distinguishing the response of the fissile system to the introduced source from its response to any internal or inherent sources. This ability combined with the enhanced sensitivity of higher order signatures indicates that these techniques will be of significant utility in a variety of applications. Potential applications include enhanced radiation signature identification of weapons components for nuclear disarmament and safeguards applications and augmented nondestructive analysis of spent nuclear fuel. In general, these techniques expand present capabilities in the analysis of subcritical measurements.

Population Genetic Analysis Infers Migration Pathways of Phytophthora ramorum in US Nurseries

PubMed Central

Goss, Erica M.; Larsen, Meg; Chastagner, Gary A.; Givens, Donald R.; Grünwald, Niklaus J.

2009-01-01

Recently introduced, exotic plant pathogens may exhibit low genetic diversity and be limited to clonal reproduction. However, rapidly mutating molecular markers such as microsatellites can reveal genetic variation within these populations and be used to model putative migration patterns. Phytophthora ramorum is the exotic pathogen, discovered in the late 1990s, that is responsible for sudden oak death in California forests and ramorum blight of common ornamentals. The nursery trade has moved this pathogen from source populations on the West Coast to locations across the United States, thus risking introduction to other native forests. We examined the genetic diversity of P. ramorum in United States nurseries by microsatellite genotyping 279 isolates collected from 19 states between 2004 and 2007. Of the three known P. ramorum clonal lineages, the most common and genetically diverse lineage in the sample was NA1. Two eastward migration pathways were revealed in the clustering of NA1 isolates into two groups, one containing isolates from Connecticut, Oregon, and Washington and the other isolates from California and the remaining states. This finding is consistent with trace forward analyses conducted by the US Department of Agriculture's Animal and Plant Health Inspection Service. At the same time, genetic diversities in several states equaled those observed in California, Oregon, and Washington and two-thirds of multilocus genotypes exhibited limited geographic distributions, indicating that mutation was common during or subsequent to migration. Together, these data suggest that migration, rapid mutation, and genetic drift all play a role in structuring the genetic diversity of P. ramorum in US nurseries. This work demonstrates that fast-evolving genetic markers can be used to examine the evolutionary processes acting on recently introduced pathogens and to infer their putative migration patterns, thus showing promise for the application of forensics to plant pathogens. PMID:19774068

Collective decision dynamics in the presence of external drivers

NASA Astrophysics Data System (ADS)

Bassett, Danielle S.; Alderson, David L.; Carlson, Jean M.

2012-09-01

We develop a sequence of models describing information transmission and decision dynamics for a network of individual agents subject to multiple sources of influence. Our general framework is set in the context of an impending natural disaster, where individuals, represented by nodes on the network, must decide whether or not to evacuate. Sources of influence include a one-to-many externally driven global broadcast as well as pairwise interactions, across links in the network, in which agents transmit either continuous opinions or binary actions. We consider both uniform and variable threshold rules on the individual opinion as baseline models for decision making. Our results indicate that (1) social networks lead to clustering and cohesive action among individuals, (2) binary information introduces high temporal variability and stagnation, and (3) information transmission over the network can either facilitate or hinder action adoption, depending on the influence of the global broadcast relative to the social network. Our framework highlights the essential role of local interactions between agents in predicting collective behavior of the population as a whole.

Irruptive dynamics of introduced caribou on Adak Island, Alaska: an evaluation of Riney-Caughley model predictions

USGS Publications Warehouse

Ricca, Mark A.; Van Vuren, Dirk H.; Weckerly, Floyd W.; Williams, Jeffrey C.; Miles, A. Keith

2014-01-01

Large mammalian herbivores introduced to islands without predators are predicted to undergo irruptive population and spatial dynamics, but only a few well-documented case studies support this paradigm. We used the Riney-Caughley model as a framework to test predictions of irruptive population growth and spatial expansion of caribou (Rangifer tarandus granti) introduced to Adak Island in the Aleutian archipelago of Alaska in 1958 and 1959. We utilized a time series of spatially explicit counts conducted on this population intermittently over a 54-year period. Population size increased from 23 released animals to approximately 2900 animals in 2012. Population dynamics were characterized by two distinct periods of irruptive growth separated by a long time period of relative stability, and the catalyst for the initial irruption was more likely related to annual variation in hunting pressure than weather conditions. An unexpected pattern resembling logistic population growth occurred between the peak of the second irruption in 2005 and the next survey conducted seven years later in 2012. Model simulations indicated that an increase in reported harvest alone could not explain the deceleration in population growth, yet high levels of unreported harvest combined with increasing density-dependent feedbacks on fecundity and survival were the most plausible explanation for the observed population trend. No studies of introduced island Rangifer have measured a time series of spatial use to the extent described in this study. Spatial use patterns during the post-calving season strongly supported Riney-Caughley model predictions, whereby high-density core areas expanded outwardly as population size increased. During the calving season, caribou displayed marked site fidelity across the full range of population densities despite availability of other suitable habitats for calving. Finally, dispersal and reproduction on neighboring Kagalaska Island represented a new dispersal front for irruptive dynamics and a new challenge for resource managers. The future demography of caribou on both islands is far from certain, yet sustained and significant hunting pressure should be a vital management tool.

Who, What, When, Where? Determining the Health Implications of Wildfire Smoke Exposure

NASA Astrophysics Data System (ADS)

Ford, B.; Lassman, W.; Gan, R.; Burke, M.; Pfister, G.; Magzamen, S.; Fischer, E. V.; Volckens, J.; Pierce, J. R.

2016-12-01

Exposure to poor air quality is associated with negative impacts on human health. A large natural source of PM in the western U.S. is from wildland fires. Accurately attributing health endpoints to wildland-fire smoke requires a determination of the exposed population. This is a difficult endeavor because most current methods for monitoring air quality are not at high temporal and spatial resolutions. Therefore, there is a growing effort to include multiple datasets and create blended products of smoke exposure that can exploit the strengths of each dataset. In this work, we combine model (WRF-Chem) simulations, NASA satellite (MODIS) observations, and in-situ surface monitors to improve exposure estimates. We will also introduce a social-media dataset of self-reported smoke/haze/pollution to improve population-level exposure estimates for the summer of 2015. Finally, we use these detailed exposure estimates in different epidemiologic study designs to provide an in-depth understanding of the role wildfire exposure plays on health outcomes.

Modest genetic differentiation among North American populations of Sarcocystis neurona may reflect expansion in its geographic range.

PubMed

Sundar, N; Asmundsson, I M; Thomas, N J; Samuel, M D; Dubey, J P; Rosenthal, B M

2008-03-25

Sarcocystis neurona is an important cause of neurological disease in horses (equine protozoal myeloencephalitis, EPM) and sea otters in the United States. In addition, EPM-like disease has been diagnosed in several other land and marine mammals. Opossums are its only definitive hosts. Little genetic diversity among isolates of S. neurona from different hosts has been reported. Here, we used 11 microsatellites to characterize S. neurona DNA isolated from natural infections in 22 sea otters (Enhydra lutris) from California and Washington and in 11 raccoons (Procyon lotor) and 1 striped skunk (Mephitis mephitis) from Wisconsin. By jointly analyzing these 34 isolates with 26 isolates previously reported, we determined that geographic barriers may limit S. neurona dispersal and that only a limited subset of possible parasite genotypes may have been introduced to recently established opossum populations. Moreover, our study confirms that diverse intermediate hosts share a common infection source, the opossum (Didelphis virginiana).

Asymmetric Evolutionary Games

PubMed Central

McAvoy, Alex; Hauert, Christoph

2015-01-01

Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner’s Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games. PMID:26308326

Modest genetic differentiation among North American populations of Sarcocystic neurona may reflect expansion in its geographic range

USGS Publications Warehouse

Sundar, N.; Asmundsson, I.M.; Thomas, N.J.; Samuel, M.D.; Dubey, J.P.; Rosenthal, B.M.

2008-01-01

Sarcocystis neurona is an important cause of neurological disease in horses (equine protozoal myeloencephalitis, EPM) and sea otters in the United States. In addition, EPM-like disease has been diagnosed in several other land and marine mammals. Opossums are its only definitive hosts. Little genetic diversity among isolates of S. neurona from different hosts has been reported. Here, we used 11 microsatellites to characterize S. neurona DNA isolated from natural infections in 22 sea otters (Enhydra lutris) from California and Washington and in 11 raccoons (Procyon lotor) and 1 striped skunk (Mephitis mephitis) from Wisconsin. By jointly analyzing these 34 isolates with 26 isolates previously reported, we determined that geographic barriers may limit S. neurona dispersal and that only a limited subset of possible parasite genotypes may have been introduced to recently established opossum populations. Moreover, our study confirms that diverse intermediate hosts share a common infection source, the opossum (Didelphis virginiana).

Augmentative Biological Control Using Parasitoids for Fruit Fly Management in Brazil

PubMed Central

Garcia, Flávio R. M.; Ricalde, Marcelo P.

2012-01-01

The history of classical biological control of fruit flies in Brazil includes two reported attempts in the past 70 years. The first occurred in 1937 when an African species of parasitoid larvae (Tetrastichus giffardianus) was introduced to control the Mediterranean fruit fly, Ceratitis capitata and other tephritids. The second occurred in September 1994 when the exotic parasitoid Diachasmimorpha longicaudata, originally from Gainesville, Florida, was introduced by a Brazilian agricultural corporation (EMBRAPA) to evaluate the parasitoid’s potential for the biological control of Anastrepha spp. and Ceratitis capitata. Although there are numerous native Brazilian fruit fly parasitoids, mass rearing of these native species is difficult. Thus, D. longicaudata was chosen due to its specificity for the family Tephritidae and its ease of laboratory rearing. In this paper we review the literature on Brazilian fruit fly biological control and suggest that those tactics can be used on a large scale, together creating a biological barrier to the introduction of new fruit fly populations, reducing the source of outbreaks and the risk of species spread, while decreasing the use of insecticides on fruit destined for domestic and foreign markets. PMID:26466795

Savant Genome Browser 2: visualization and analysis for population-scale genomics.

PubMed

Fiume, Marc; Smith, Eric J M; Brook, Andrew; Strbenac, Dario; Turner, Brian; Mezlini, Aziz M; Robinson, Mark D; Wodak, Shoshana J; Brudno, Michael

2012-07-01

High-throughput sequencing (HTS) technologies are providing an unprecedented capacity for data generation, and there is a corresponding need for efficient data exploration and analysis capabilities. Although most existing tools for HTS data analysis are developed for either automated (e.g. genotyping) or visualization (e.g. genome browsing) purposes, such tools are most powerful when combined. For example, integration of visualization and computation allows users to iteratively refine their analyses by updating computational parameters within the visual framework in real-time. Here we introduce the second version of the Savant Genome Browser, a standalone program for visual and computational analysis of HTS data. Savant substantially improves upon its predecessor and existing tools by introducing innovative visualization modes and navigation interfaces for several genomic datatypes, and synergizing visual and automated analyses in a way that is powerful yet easy even for non-expert users. We also present a number of plugins that were developed by the Savant Community, which demonstrate the power of integrating visual and automated analyses using Savant. The Savant Genome Browser is freely available (open source) at www.savantbrowser.com.

Savant Genome Browser 2: visualization and analysis for population-scale genomics

PubMed Central

Smith, Eric J. M.; Brook, Andrew; Strbenac, Dario; Turner, Brian; Mezlini, Aziz M.; Robinson, Mark D.; Wodak, Shoshana J.; Brudno, Michael

2012-01-01

High-throughput sequencing (HTS) technologies are providing an unprecedented capacity for data generation, and there is a corresponding need for efficient data exploration and analysis capabilities. Although most existing tools for HTS data analysis are developed for either automated (e.g. genotyping) or visualization (e.g. genome browsing) purposes, such tools are most powerful when combined. For example, integration of visualization and computation allows users to iteratively refine their analyses by updating computational parameters within the visual framework in real-time. Here we introduce the second version of the Savant Genome Browser, a standalone program for visual and computational analysis of HTS data. Savant substantially improves upon its predecessor and existing tools by introducing innovative visualization modes and navigation interfaces for several genomic datatypes, and synergizing visual and automated analyses in a way that is powerful yet easy even for non-expert users. We also present a number of plugins that were developed by the Savant Community, which demonstrate the power of integrating visual and automated analyses using Savant. The Savant Genome Browser is freely available (open source) at www.savantbrowser.com. PMID:22638571

Radio weak lensing shear measurement in the visibility domain - II. Source extraction

NASA Astrophysics Data System (ADS)

Rivi, M.; Miller, L.

2018-05-01

This paper extends the method introduced in Rivi et al. (2016b) to measure galaxy ellipticities in the visibility domain for radio weak lensing surveys. In that paper, we focused on the development and testing of the method for the simple case of individual galaxies located at the phase centre, and proposed to extend it to the realistic case of many sources in the field of view by isolating visibilities of each source with a faceting technique. In this second paper, we present a detailed algorithm for source extraction in the visibility domain and show its effectiveness as a function of the source number density by running simulations of SKA1-MID observations in the band 950-1150 MHz and comparing original and measured values of galaxies' ellipticities. Shear measurements from a realistic population of 104 galaxies randomly located in a field of view of 1 \\deg ^2 (i.e. the source density expected for the current radio weak lensing survey proposal with SKA1) are also performed. At SNR ≥ 10, the multiplicative bias is only a factor 1.5 worse than what found when analysing individual sources, and is still comparable to the bias values reported for similar measurement methods at optical wavelengths. The additive bias is unchanged from the case of individual sources, but it is significantly larger than typically found in optical surveys. This bias depends on the shape of the uv coverage and we suggest that a uv-plane weighting scheme to produce a more isotropic shape could reduce and control additive bias.

Graph theory as a proxy for spatially explicit population models in conservation planning.

PubMed

Minor, Emily S; Urban, Dean L

2007-09-01

Spatially explicit population models (SEPMs) are often considered the best way to predict and manage species distributions in spatially heterogeneous landscapes. However, they are computationally intensive and require extensive knowledge of species' biology and behavior, limiting their application in many cases. An alternative to SEPMs is graph theory, which has minimal data requirements and efficient algorithms. Although only recently introduced to landscape ecology, graph theory is well suited to ecological applications concerned with connectivity or movement. This paper compares the performance of graph theory to a SEPM in selecting important habitat patches for Wood Thrush (Hylocichla mustelina) conservation. We use both models to identify habitat patches that act as population sources and persistent patches and also use graph theory to identify patches that act as stepping stones for dispersal. Correlations of patch rankings were very high between the two models. In addition, graph theory offers the ability to identify patches that are very important to habitat connectivity and thus long-term population persistence across the landscape. We show that graph theory makes very similar predictions in most cases and in other cases offers insight not available from the SEPM, and we conclude that graph theory is a suitable and possibly preferable alternative to SEPMs for species conservation in heterogeneous landscapes.

No evidence of enemy release in pathogen and microbial communities of common wasps (Vespula vulgaris) in their native and introduced range.

PubMed

Lester, Philip J; Bosch, Peter J; Gruber, Monica A M; Kapp, Eugene A; Peng, Lifeng; Brenton-Rule, Evan C; Buchanan, Joe; Stanislawek, Wlodek L; Archer, Michael; Corley, Juan C; Masciocchi, Maitè; Van Oystaeyen, Annette; Wenseleers, Tom

2015-01-01

When invasive species move to new environments they typically experience population bottlenecks that limit the probability that pathogens and parasites are also moved. The invasive species may thus be released from biotic interactions that can be a major source of density-dependent mortality, referred to as enemy release. We examined for evidence of enemy release in populations of the common wasp (Vespula vulgaris), which attains high densities and represents a major threat to biodiversity in its invaded range. Mass spectrometry proteomic methods were used to compare the microbial communities in wasp populations in the native (Belgium and England) and invaded range (Argentina and New Zealand). We found no evidence of enemy release, as the number of microbial taxa was similar in both the introduced and native range. However, some evidence of distinctiveness in the microbial communities was observed between countries. The pathogens observed were similar to a variety of taxa observed in honey bees. These taxa included Nosema, Paenibacillus, and Yersina spp. Genomic methods confirmed a diversity of Nosema spp., Actinobacteria, and the Deformed wing and Kashmir bee viruses. We also analysed published records of bacteria, viruses, nematodes and fungi from both V. vulgaris and the related invader V. germanica. Thirty-three different microorganism taxa have been associated with wasps including Kashmir bee virus and entomophagous fungi such as Aspergillus flavus. There was no evidence that the presence or absence of these microorganisms was dependent on region of wasp samples (i.e. their native or invaded range). Given the similarity of the wasp pathogen fauna to that from honey bees, the lack of enemy release in wasp populations is probably related to spill-over or spill-back from bees and other social insects. Social insects appear to form a reservoir of generalist parasites and pathogens, which makes the management of wasp and bee disease difficult.

No Evidence of Enemy Release in Pathogen and Microbial Communities of Common Wasps (Vespula vulgaris) in Their Native and Introduced Range

PubMed Central

Lester, Philip J.; Kapp, Eugene A.; Peng, Lifeng; Brenton-Rule, Evan C.; Buchanan, Joe; Stanislawek, Wlodek L.; Archer, Michael; Corley, Juan C.; Masciocchi, Maitè; Van Oystaeyen, Annette; Wenseleers, Tom

2015-01-01

When invasive species move to new environments they typically experience population bottlenecks that limit the probability that pathogens and parasites are also moved. The invasive species may thus be released from biotic interactions that can be a major source of density-dependent mortality, referred to as enemy release. We examined for evidence of enemy release in populations of the common wasp (Vespula vulgaris), which attains high densities and represents a major threat to biodiversity in its invaded range. Mass spectrometry proteomic methods were used to compare the microbial communities in wasp populations in the native (Belgium and England) and invaded range (Argentina and New Zealand). We found no evidence of enemy release, as the number of microbial taxa was similar in both the introduced and native range. However, some evidence of distinctiveness in the microbial communities was observed between countries. The pathogens observed were similar to a variety of taxa observed in honey bees. These taxa included Nosema, Paenibacillus, and Yersina spp. Genomic methods confirmed a diversity of Nosema spp., Actinobacteria, and the Deformed wing and Kashmir bee viruses. We also analysed published records of bacteria, viruses, nematodes and fungi from both V. vulgaris and the related invader V. germanica. Thirty-three different microorganism taxa have been associated with wasps including Kashmir bee virus and entomophagous fungi such as Aspergillus flavus. There was no evidence that the presence or absence of these microorganisms was dependent on region of wasp samples (i.e. their native or invaded range). Given the similarity of the wasp pathogen fauna to that from honey bees, the lack of enemy release in wasp populations is probably related to spill-over or spill-back from bees and other social insects. Social insects appear to form a reservoir of generalist parasites and pathogens, which makes the management of wasp and bee disease difficult. PMID:25798856

Aedes aegypti on Madeira Island (Portugal): genetic variation of a recently introduced dengue vector

PubMed Central

Seixas, Gonçalo; Salgueiro, Patrícia; Silva, Ana Clara; Campos, Melina; Spenassatto, Carine; Reyes-Lugo, Matías; Novo, Maria Teresa; Ribolla, Paulo Eduardo Martins; Pinto, João Pedro Soares da Silva; Sousa, Carla Alexandra

2013-01-01

The increasing population of Aedes aegypti mosquitoes on Madeira Island (Portugal) resulted in the first autochthonous dengue outbreak, which occurred in October 2012. Our study establishes the first genetic evaluation based on the mitochondrial DNA (mtDNA) genes [cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 4 (ND4)] and knockdown resistance ( kdr ) mutations exploring the colonisation history and the genetic diversity of this insular vector population. We included mosquito populations from Brazil and Venezuela in the analysis as putative geographic sources. The Ae. aegypti population from Madeira showed extremely low mtDNA genetic variability, with a single haplotype for COI and ND4. We also detected the presence of two important kdr mutations and the quasi-fixation of one of these mutations (F1534C). These results are consistent with a unique recent founder event that occurred on the island of Ae. aegypti mosquitoes that carry kdr mutations associated with insecticide resistance. Finally, we also report the presence of the F1534C kdr mutation in the Brazil and Venezuela populations. To our knowledge, this is the first time this mutation has been found in South American Ae. aegypti mosquitoes. Given the present risk of Ae. aegypti re-invading continental Europe from Madeira and the recent dengue outbreaks on the island, this information is important to plan surveillance and control measures. PMID:24473797

Aedes aegypti on Madeira Island (Portugal): genetic variation of a recently introduced dengue vector.

PubMed

Seixas, Gonçalo; Salgueiro, Patrícia; Silva, Ana Clara; Campos, Melina; Spenassatto, Carine; Reyes-Lugo, Matías; Novo, Maria Teresa; Ribolla, Paulo Eduardo Martins; Silva Pinto, João Pedro Soares da; Sousa, Carla Alexandra

2013-01-01

The increasing population of Aedes aegypti mosquitoes on Madeira Island (Portugal) resulted in the first autochthonous dengue outbreak, which occurred in October 2012. Our study establishes the first genetic evaluation based on the mitochondrial DNA (mtDNA) genes [cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 4 (ND4)] and knockdown resistance (kdr) mutations exploring the colonisation history and the genetic diversity of this insular vector population. We included mosquito populations from Brazil and Venezuela in the analysis as putative geographic sources. The Ae. aegypti population from Madeira showed extremely low mtDNA genetic variability, with a single haplotype for COI and ND4. We also detected the presence of two important kdr mutations and the quasi-fixation of one of these mutations (F1534C). These results are consistent with a unique recent founder event that occurred on the island of Ae. aegypti mosquitoes that carry kdr mutations associated with insecticide resistance. Finally, we also report the presence of the F1534C kdr mutation in the Brazil and Venezuela populations. To our knowledge, this is the first time this mutation has been found in South American Ae. aegypti mosquitoes. Given the present risk of Ae. aegypti re-invading continental Europe from Madeira and the recent dengue outbreaks on the island, this information is important to plan surveillance and control measures.

PLINK: A Tool Set for Whole-Genome Association and Population-Based Linkage Analyses

PubMed Central

Purcell, Shaun ; Neale, Benjamin ; Todd-Brown, Kathe ; Thomas, Lori ; Ferreira, Manuel A. R. ; Bender, David ; Maller, Julian ; Sklar, Pamela ; de Bakker, Paul I. W. ; Daly, Mark J. ; Sham, Pak C. 

2007-01-01

Whole-genome association studies (WGAS) bring new computational, as well as analytic, challenges to researchers. Many existing genetic-analysis tools are not designed to handle such large data sets in a convenient manner and do not necessarily exploit the new opportunities that whole-genome data bring. To address these issues, we developed PLINK, an open-source C/C++ WGAS tool set. With PLINK, large data sets comprising hundreds of thousands of markers genotyped for thousands of individuals can be rapidly manipulated and analyzed in their entirety. As well as providing tools to make the basic analytic steps computationally efficient, PLINK also supports some novel approaches to whole-genome data that take advantage of whole-genome coverage. We introduce PLINK and describe the five main domains of function: data management, summary statistics, population stratification, association analysis, and identity-by-descent estimation. In particular, we focus on the estimation and use of identity-by-state and identity-by-descent information in the context of population-based whole-genome studies. This information can be used to detect and correct for population stratification and to identify extended chromosomal segments that are shared identical by descent between very distantly related individuals. Analysis of the patterns of segmental sharing has the potential to map disease loci that contain multiple rare variants in a population-based linkage analysis. PMID:17701901

The Diversity-Weighted Living Planet Index: Controlling for Taxonomic Bias in a Global Biodiversity Indicator.

PubMed

McRae, Louise; Deinet, Stefanie; Freeman, Robin

2017-01-01

As threats to species continue to increase, precise and unbiased measures of the impact these pressures are having on global biodiversity are urgently needed. Some existing indicators of the status and trends of biodiversity largely rely on publicly available data from the scientific and grey literature, and are therefore prone to biases introduced through over-representation of well-studied groups and regions in monitoring schemes. This can give misleading estimates of biodiversity trends. Here, we report on an approach to tackle taxonomic and geographic bias in one such indicator (Living Planet Index) by accounting for the estimated number of species within biogeographical realms, and the relative diversity of species within them. Based on a proportionally weighted index, we estimate a global population decline in vertebrate species between 1970 and 2012 of 58% rather than 20% from an index with no proportional weighting. From this data set, comprising 14,152 populations of 3,706 species from 3,095 data sources, we also find that freshwater populations have declined by 81%, marine populations by 36%, and terrestrial populations by 38% when using proportional weighting (compared to trends of -46%, +12% and +15% respectively). These results not only show starker declines than previously estimated, but suggests that those species for which there is poorer data coverage may be declining more rapidly.

The Diversity-Weighted Living Planet Index: Controlling for Taxonomic Bias in a Global Biodiversity Indicator

PubMed Central

Deinet, Stefanie; Freeman, Robin

2017-01-01

As threats to species continue to increase, precise and unbiased measures of the impact these pressures are having on global biodiversity are urgently needed. Some existing indicators of the status and trends of biodiversity largely rely on publicly available data from the scientific and grey literature, and are therefore prone to biases introduced through over-representation of well-studied groups and regions in monitoring schemes. This can give misleading estimates of biodiversity trends. Here, we report on an approach to tackle taxonomic and geographic bias in one such indicator (Living Planet Index) by accounting for the estimated number of species within biogeographical realms, and the relative diversity of species within them. Based on a proportionally weighted index, we estimate a global population decline in vertebrate species between 1970 and 2012 of 58% rather than 20% from an index with no proportional weighting. From this data set, comprising 14,152 populations of 3,706 species from 3,095 data sources, we also find that freshwater populations have declined by 81%, marine populations by 36%, and terrestrial populations by 38% when using proportional weighting (compared to trends of -46%, +12% and +15% respectively). These results not only show starker declines than previously estimated, but suggests that those species for which there is poorer data coverage may be declining more rapidly. PMID:28045977

An Easy Phylogenetically Informative Method to Trace the Globally Invasive Potamopyrgus Mud Snail from River's eDNA.

PubMed

Clusa, Laura; Ardura, Alba; Gower, Fiona; Miralles, Laura; Tsartsianidou, Valentina; Zaiko, Anastasija; Garcia-Vazquez, Eva

2016-01-01

Potamopyrgus antipodarum (New Zealand mud snail) is a prosobranch mollusk native to New Zealand with a wide invasive distribution range. Its non-indigenous populations are reported from Australia, Asia, Europe and North America. Being an extremely tolerant species, Potamopyrgus is capable to survive in a great range of salinity and temperature conditions, which explains its high invasiveness and successful spread outside the native range. Here we report the first finding of Potamopyrgus antipodarum in a basin of the Cantabrian corridor in North Iberia (Bay of Biscay, Spain). Two haplotypes already described in Europe were found in different sectors of River Nora (Nalon basin), suggesting the secondary introductions from earlier established invasive populations. To enhance the surveillance of the species and tracking its further spread in the region, we developed a specific set of primers for the genus Potamopyrgus that amplify a fragment of 16S rDNA. The sequences obtained from PCR on DNA extracted from tissue and water samples (environmental DNA, eDNA) were identical in each location, suggesting clonal reproduction of the introduced individuals. Multiple introduction events from different source populations were inferred from our sequence data. The eDNA tool developed here can serve for tracing New Zealand mud snail populations outside its native range, and for inventorying mud snail population assemblages in the native settings if high throughput sequencing methodologies are employed.

An Easy Phylogenetically Informative Method to Trace the Globally Invasive Potamopyrgus Mud Snail from River’s eDNA

PubMed Central

Clusa, Laura; Ardura, Alba; Gower, Fiona; Miralles, Laura; Tsartsianidou, Valentina; Zaiko, Anastasija; Garcia-Vazquez, Eva

2016-01-01

Potamopyrgus antipodarum (New Zealand mud snail) is a prosobranch mollusk native to New Zealand with a wide invasive distribution range. Its non-indigenous populations are reported from Australia, Asia, Europe and North America. Being an extremely tolerant species, Potamopyrgus is capable to survive in a great range of salinity and temperature conditions, which explains its high invasiveness and successful spread outside the native range. Here we report the first finding of Potamopyrgus antipodarum in a basin of the Cantabrian corridor in North Iberia (Bay of Biscay, Spain). Two haplotypes already described in Europe were found in different sectors of River Nora (Nalon basin), suggesting the secondary introductions from earlier established invasive populations. To enhance the surveillance of the species and tracking its further spread in the region, we developed a specific set of primers for the genus Potamopyrgus that amplify a fragment of 16S rDNA. The sequences obtained from PCR on DNA extracted from tissue and water samples (environmental DNA, eDNA) were identical in each location, suggesting clonal reproduction of the introduced individuals. Multiple introduction events from different source populations were inferred from our sequence data. The eDNA tool developed here can serve for tracing New Zealand mud snail populations outside its native range, and for inventorying mud snail population assemblages in the native settings if high throughput sequencing methodologies are employed. PMID:27706172

Abundance of introduced species at home predicts abundance away in herbaceous communities

USGS Publications Warehouse

Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

2011-01-01

Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

Multiple sparse volumetric priors for distributed EEG source reconstruction.

PubMed

Strobbe, Gregor; van Mierlo, Pieter; De Vos, Maarten; Mijović, Bogdan; Hallez, Hans; Van Huffel, Sabine; López, José David; Vandenberghe, Stefaan

2014-10-15

We revisit the multiple sparse priors (MSP) algorithm implemented in the statistical parametric mapping software (SPM) for distributed EEG source reconstruction (Friston et al., 2008). In the present implementation, multiple cortical patches are introduced as source priors based on a dipole source space restricted to a cortical surface mesh. In this note, we present a technique to construct volumetric cortical regions to introduce as source priors by restricting the dipole source space to a segmented gray matter layer and using a region growing approach. This extension allows to reconstruct brain structures besides the cortical surface and facilitates the use of more realistic volumetric head models including more layers, such as cerebrospinal fluid (CSF), compared to the standard 3-layered scalp-skull-brain head models. We illustrated the technique with ERP data and anatomical MR images in 12 subjects. Based on the segmented gray matter for each of the subjects, cortical regions were created and introduced as source priors for MSP-inversion assuming two types of head models. The standard 3-layered scalp-skull-brain head models and extended 4-layered head models including CSF. We compared these models with the current implementation by assessing the free energy corresponding with each of the reconstructions using Bayesian model selection for group studies. Strong evidence was found in favor of the volumetric MSP approach compared to the MSP approach based on cortical patches for both types of head models. Overall, the strongest evidence was found in favor of the volumetric MSP reconstructions based on the extended head models including CSF. These results were verified by comparing the reconstructed activity. The use of volumetric cortical regions as source priors is a useful complement to the present implementation as it allows to introduce more complex head models and volumetric source priors in future studies. Copyright © 2014 Elsevier Inc. All rights reserved.

Nitrate source apportionment using a combined dual isotope, chemical and bacterial property, and Bayesian model approach in river systems

NASA Astrophysics Data System (ADS)

Xia, Yongqiu; Li, Yuefei; Zhang, Xinyu; Yan, Xiaoyuan

2017-01-01

Nitrate (NO3-) pollution is a serious problem worldwide, particularly in countries with intensive agricultural and population activities. Previous studies have used δ15N-NO3- and δ18O-NO3- to determine the NO3- sources in rivers. However, this approach is subject to substantial uncertainties and limitations because of the numerous NO3- sources, the wide isotopic ranges, and the existing isotopic fractionations. In this study, we outline a combined procedure for improving the determination of NO3- sources in a paddy agriculture-urban gradient watershed in eastern China. First, the main sources of NO3- in the Qinhuai River were examined by the dual-isotope biplot approach, in which we narrowed the isotope ranges using site-specific isotopic results. Next, the bacterial groups and chemical properties of the river water were analyzed to verify these sources. Finally, we introduced a Bayesian model to apportion the spatiotemporal variations of the NO3- sources. Denitrification was first incorporated into the Bayesian model because denitrification plays an important role in the nitrogen pathway. The results showed that fertilizer contributed large amounts of NO3- to the surface water in traditional agricultural regions, whereas manure effluents were the dominant NO3- source in intensified agricultural regions, especially during the wet seasons. Sewage effluents were important in all three land uses and exhibited great differences between the dry season and the wet season. This combined analysis quantitatively delineates the proportion of NO3- sources from paddy agriculture to urban river water for both dry and wet seasons and incorporates isotopic fractionation and uncertainties in the source compositions.

Rapid Development of Adaptive, Climate-Driven Clinal Variation in Seed Mass in the Invasive Annual Forb Echium plantagineum L.

PubMed Central

Konarzewski, Tara K.; Murray, Brad R.; Godfree, Robert C.

2012-01-01

We examined adaptive clinal variation in seed mass among populations of an invasive annual species, Echium plantagineum, in response to climatic selection. We collected seeds from 34 field populations from a 1,000 km long temperature and rainfall gradient across the species' introduced range in south-eastern Australia. Seeds were germinated, grown to reproductive age under common glasshouse conditions, and progeny seeds were harvested and weighed. Analyses showed that seed mass was significantly related to climatic factors, with populations sourced from hotter, more arid sites producing heavier seeds than populations from cooler and wetter sites. Seed mass was not related to edaphic factors. We also found that seed mass was significantly related to both longitude and latitude with each degree of longitude west and latitude north increasing seed mass by around 2.5% and 4% on average. There was little evidence that within-population or between-population variation in seed mass varied in a systematic manner across the study region. Our findings provide compelling evidence for development of a strong cline in seed mass across the geographic range of a widespread and highly successful invasive annual forb. Since large seed mass is known to provide reproductive assurance for plants in arid environments, our results support the hypothesis that the fitness and range potential of invasive species can increase as a result of genetic divergence of populations along broad climatic gradients. In E. plantagineum population-level differentiation has occurred in 150 years or less, indicating that the adaptation process can be rapid. PMID:23284621

From blackbirds to black holes: Investigating capture-recapture methods for time domain astronomy

NASA Astrophysics Data System (ADS)

Laycock, Silas G. T.

2017-07-01

In time domain astronomy, recurrent transients present a special problem: how to infer total populations from limited observations. Monitoring observations may give a biassed view of the underlying population due to limitations on observing time, visibility and instrumental sensitivity. A similar problem exists in the life sciences, where animal populations (such as migratory birds) or disease prevalence, must be estimated from sparse and incomplete data. The class of methods termed Capture-Recapture is used to reconstruct population estimates from time-series records of encounters with the study population. This paper investigates the performance of Capture-Recapture methods in astronomy via a series of numerical simulations. The Blackbirds code simulates monitoring of populations of transients, in this case accreting binary stars (neutron star or black hole accreting from a stellar companion) under a range of observing strategies. We first generate realistic light-curves for populations of binaries with contrasting orbital period distributions. These models are then randomly sampled at observing cadences typical of existing and planned monitoring surveys. The classical capture-recapture methods, Lincoln-Peterson, Schnabel estimators, related techniques, and newer methods implemented in the Rcapture package are compared. A general exponential model based on the radioactive decay law is introduced which is demonstrated to recover (at 95% confidence) the underlying population abundance and duty cycle, in a fraction of the observing visits (10-50%) required to discover all the sources in the simulation. Capture-Recapture is a promising addition to the toolbox of time domain astronomy, and methods implemented in R by the biostats community can be readily called from within python.

PyClone: statistical inference of clonal population structure in cancer.

PubMed

Roth, Andrew; Khattra, Jaswinder; Yap, Damian; Wan, Adrian; Laks, Emma; Biele, Justina; Ha, Gavin; Aparicio, Samuel; Bouchard-Côté, Alexandre; Shah, Sohrab P

2014-04-01

We introduce PyClone, a statistical model for inference of clonal population structures in cancers. PyClone is a Bayesian clustering method for grouping sets of deeply sequenced somatic mutations into putative clonal clusters while estimating their cellular prevalences and accounting for allelic imbalances introduced by segmental copy-number changes and normal-cell contamination. Single-cell sequencing validation demonstrates PyClone's accuracy.

The Ecological Genetics of Introduced Populations of the Giant Toad BUFO MARINUS. II. Effective Population Size

PubMed Central

Easteal, Simon

1985-01-01

The allele frequencies are described at ten polymorphic enzyme loci (of a total of 22 loci sampled) in 15 populations of the neotropical giant toad, Bufo marinus, introduced to Hawaii and Australia in the 1930s. The history of establishment of the ten populations is described and used as a framework for the analysis of allele frequency variances. The variances are used to determine the effective sizes of the populations. The estimates obtained (390 and 346) are reasonably precise, homogeneous between localities and much smaller than estimates of neighborhood size obtained previously using ecological methods. This discrepancy is discussed, and it is concluded that the estimates obtained here using genetic methods are the more reliable. PMID:3922852

Community-based interventions in prepared-food sources: a systematic review.

PubMed

Gittelsohn, Joel; Lee-Kwan, Seung Hee; Batorsky, Benjamin

2013-10-31

Food purchased from prepared-food sources has become a major part of the American diet and is linked to increased rates of chronic disease. Many interventions targeting prepared-food sources have been initiated with the goal of promoting healthful options. The objective of this study was to provide a systematic review of interventions in prepared-food sources in community settings. We used PubMed and Google Scholar and identified 13 interventions that met these criteria: 1) focused on prepared-food sources in public community settings, 2) used an impact evaluation, 3) had written documentation, and 4) took place after 1990. We conducted interviews with intervention staff to obtain additional information. Reviewers extracted and reported data in table format to ensure comparability. Interventions mostly targeted an urban population, predominantly white, in a range of income levels. The most common framework used was social marketing theory. Most interventions used a nonexperimental design. All made use of signage and menu labeling to promote healthful food options. Several promoted more healthful cooking methods; only one introduced new healthful menu options. Levels of feasibility and sustainability were high; sales results showed increased purchasing of healthful options. Measures among consumers were limited but in many cases showed improved awareness and frequency of purchase of promoted foods. Interventions in prepared-food sources show initial promising results at the store level. Future studies should focus on improved study designs, expanding intervention strategies beyond signage and assessing impact among consumers.

Community-Based Interventions in Prepared-Food Sources: A Systematic Review

PubMed Central

Lee-Kwan, Seung Hee; Batorsky, Benjamin

2013-01-01

Introduction Food purchased from prepared-food sources has become a major part of the American diet and is linked to increased rates of chronic disease. Many interventions targeting prepared-food sources have been initiated with the goal of promoting healthful options. The objective of this study was to provide a systematic review of interventions in prepared-food sources in community settings. Methods We used PubMed and Google Scholar and identified 13 interventions that met these criteria: 1) focused on prepared-food sources in public community settings, 2) used an impact evaluation, 3) had written documentation, and 4) took place after 1990. We conducted interviews with intervention staff to obtain additional information. Reviewers extracted and reported data in table format to ensure comparability. Results Interventions mostly targeted an urban population, predominantly white, in a range of income levels. The most common framework used was social marketing theory. Most interventions used a nonexperimental design. All made use of signage and menu labeling to promote healthful food options. Several promoted more healthful cooking methods; only one introduced new healthful menu options. Levels of feasibility and sustainability were high; sales results showed increased purchasing of healthful options. Measures among consumers were limited but in many cases showed improved awareness and frequency of purchase of promoted foods. Conclusion Interventions in prepared-food sources show initial promising results at the store level. Future studies should focus on improved study designs, expanding intervention strategies beyond signage and assessing impact among consumers. PMID:24176084

40 CFR 463.36 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

....36 Pretreatment standards for new sources. (a) PSNS for bis(2-ethylhexyl) phthalate, di-n-butyl phthalate, and dimethyl phthalate are reserved. (b) Any new source subject to this subpart that introduces...

Global genetic variation in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae) and the endosymbiont Wolbachia: links between Iran and the USA detected.

PubMed

Lashkari, Mohammadreza; Manzari, Shahab; Sahragard, Ahad; Malagnini, Valeria; Boykin, Laura M; Hosseini, Reza

2014-07-01

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is one of the most serious pests of citrus in the world, because it transmits the pathogen that causes citrus greening disease. To determine genetic variation among geographic populations of D. citri, microsatellite markers, mitochondrial gene cytochrome oxidase I (mtCOI) and the Wolbachia-Diaphorina, wDi, gene wsp sequence data were used to characterize Iranian and Pakistani populations. Also, a Bayesian phylogenetic technique was utilized to elucidate the relationships among the sequences data in this study and all mtCOI and wsp sequence data available in GenBank and the Wolbachia database. Microsatellite markers revealed significant genetic differentiation among Iranian populations, as well as between Iranian and Pakistani populations (FST  = 0.0428, p < 0.01). Within Iran, the Sistan-Baluchestan population is significantly different from the Hormozgan (Fareghan) and Fars populations. By contrast, mtCOI data revealed two polymorphic sites separating the sequences from Iran and Pakistan. Global phylogenetic analyses showed that D. citri populations in Iran, India, Saudi Arabia, Brazil, Mexico, Florida and Texas (USA) are similar. Wolbachia, wDi, wsp sequences were similar among Iranian populations, but different between Iranian and Pakistani populations. The South West Asia (SWA) group is the most likely source of the introduced Iranian populations of D. citri. This assertion is also supported by the sequence similarity of the Wolbachia, wDi, strains from the Florida, USA and Iranian D. citri. These results should be considered when looking for biological controls in either country. © 2013 Society of Chemical Industry.

Population demographics and genetic diversity in remnant and translocated populations of sea otters

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Cronin, M.A.; Scribner, K.T.

1999-01-01

The effects of small population size on genetic diversity and subsequent population recovery are theoretically predicted, but few empirical data are available to describe those relations. We use data from four remnant and three translocated sea otter (Enhydra lutris) populations to examine relations among magnitude and duration of minimum population size, population growth rates, and genetic variation. Metochondrial (mt)DNA haplotype diversity was correlated with the number of years at minimum population size (r = -0.741, p = 0.038) and minimum population size (r = 0.709, p = 0.054). We found no relation between population growth and haplotype diversity, altough growth was significantly greater in translocated than in remnant populations. Haplotype diversity in populations established from two sources was higher than in a population established from a single source and was higher than in the respective source populations. Haplotype frequencies in translocated populations of founding sizes of 4 and 28 differed from expected, indicating genetic drift and differential reproduction between source populations, whereas haplotype frequencies in a translocated population with a founding size of 150 did not. Relations between population demographics and genetic characteristics suggest that genetic sampling of source and translocated populations can provide valuable inferences about translocations.

Biotic mortality factors affecting emerald ash borer (Agrilus planipennis) are highly dependent on life stage and host tree crown condition.

PubMed

Jennings, D E; Duan, J J; Shrewsbury, P M

2015-10-01

Emerald ash borer (EAB), Agrilus planipennis, is a serious invasive forest pest in North America responsible for killing tens to hundreds of millions of ash trees since it was accidentally introduced in the 1990 s. Although host-plant resistance and natural enemies are known to be important sources of mortality for EAB in Asia, less is known about the importance of different sources of mortality at recently colonized sites in the invaded range of EAB, and how these relate to host tree crown condition. To further our understanding of EAB population dynamics, we used a large-scale field experiment and life-table analyses to quantify the fates of EAB larvae and the relative importance of different biotic mortality factors at 12 recently colonized sites in Maryland. We found that the fates of larvae were highly dependent on EAB life stage and host tree crown condition. In relatively healthy trees (i.e., with a low EAB infestation) and for early instars, host tree resistance was the most important mortality factor. Conversely, in more unhealthy trees (i.e., with a moderate to high EAB infestation) and for later instars, parasitism and predation were the major sources of mortality. Life-table analyses also indicated how the lack of sufficient levels of host tree resistance and natural enemies contribute to rapid population growth of EAB at recently colonized sites. Our findings provide further evidence of the mechanisms by which EAB has been able to successfully establish and spread in North America.

Embolic strokes of undetermined source in the Athens stroke registry: a descriptive analysis.

PubMed

Ntaios, George; Papavasileiou, Vasileios; Milionis, Haralambos; Makaritsis, Konstantinos; Manios, Efstathios; Spengos, Konstantinos; Michel, Patrik; Vemmos, Konstantinos

2015-01-01

A new clinical construct termed embolic stroke of undetermined source (ESUS) was recently introduced, but no such population has been described yet. Our aim is to provide a detailed descriptive analysis of an ESUS population derived from a large prospective ischemic stroke registry using the proposed diagnostic criteria. The criteria proposed by the Cryptogenic Stroke/ESUS International Working Group were applied to the Athens Stroke Registry to identify all ESUS patients. ESUS was defined as a radiologically confirmed nonlacunar brain infarct in the absence of (a) extracranial or intracranial atherosclerosis causing ≥50% luminal stenosis in arteries supplying the ischemic area, (b) major-risk cardioembolic source, and (c) any other specific cause of stroke. Among 2735 patients admitted between 1992 and 2011, 275 (10.0%) were classified as ESUS. In the majority of ESUS (74.2%), symptoms were maximal at onset. ESUS were of moderate severity (median National Institute Health Stroke Scale score, 5). The most prevalent risk factor was arterial hypertension (64.7%), and 50.9% of patients were dyslipidemic. Among potential causes of the ESUS, covert atrial fibrillation (AF) was the most prevalent: in 30 (10.9%) patients, AF was diagnosed during hospitalization for stroke recurrence, whereas in 50 (18.2%) patients AF was detected after repeated ECG monitoring during follow-up. Also, covert AF was strongly suggested in 38 patients (13.8%) but never recorded. About 10% of patients with first-ever ischemic stroke met criteria for ESUS; covert paroxysmal AF seems to be a frequent cause of ESUS. © 2014 American Heart Association, Inc.

Building essential biodiversity variables (EBVs) of species distribution and abundance at a global scale.

PubMed

Kissling, W Daniel; Ahumada, Jorge A; Bowser, Anne; Fernandez, Miguel; Fernández, Néstor; García, Enrique Alonso; Guralnick, Robert P; Isaac, Nick J B; Kelling, Steve; Los, Wouter; McRae, Louise; Mihoub, Jean-Baptiste; Obst, Matthias; Santamaria, Monica; Skidmore, Andrew K; Williams, Kristen J; Agosti, Donat; Amariles, Daniel; Arvanitidis, Christos; Bastin, Lucy; De Leo, Francesca; Egloff, Willi; Elith, Jane; Hobern, Donald; Martin, David; Pereira, Henrique M; Pesole, Graziano; Peterseil, Johannes; Saarenmaa, Hannu; Schigel, Dmitry; Schmeller, Dirk S; Segata, Nicola; Turak, Eren; Uhlir, Paul F; Wee, Brian; Hardisty, Alex R

2018-02-01

Much biodiversity data is collected worldwide, but it remains challenging to assemble the scattered knowledge for assessing biodiversity status and trends. The concept of Essential Biodiversity Variables (EBVs) was introduced to structure biodiversity monitoring globally, and to harmonize and standardize biodiversity data from disparate sources to capture a minimum set of critical variables required to study, report and manage biodiversity change. Here, we assess the challenges of a 'Big Data' approach to building global EBV data products across taxa and spatiotemporal scales, focusing on species distribution and abundance. The majority of currently available data on species distributions derives from incidentally reported observations or from surveys where presence-only or presence-absence data are sampled repeatedly with standardized protocols. Most abundance data come from opportunistic population counts or from population time series using standardized protocols (e.g. repeated surveys of the same population from single or multiple sites). Enormous complexity exists in integrating these heterogeneous, multi-source data sets across space, time, taxa and different sampling methods. Integration of such data into global EBV data products requires correcting biases introduced by imperfect detection and varying sampling effort, dealing with different spatial resolution and extents, harmonizing measurement units from different data sources or sampling methods, applying statistical tools and models for spatial inter- or extrapolation, and quantifying sources of uncertainty and errors in data and models. To support the development of EBVs by the Group on Earth Observations Biodiversity Observation Network (GEO BON), we identify 11 key workflow steps that will operationalize the process of building EBV data products within and across research infrastructures worldwide. These workflow steps take multiple sequential activities into account, including identification and aggregation of various raw data sources, data quality control, taxonomic name matching and statistical modelling of integrated data. We illustrate these steps with concrete examples from existing citizen science and professional monitoring projects, including eBird, the Tropical Ecology Assessment and Monitoring network, the Living Planet Index and the Baltic Sea zooplankton monitoring. The identified workflow steps are applicable to both terrestrial and aquatic systems and a broad range of spatial, temporal and taxonomic scales. They depend on clear, findable and accessible metadata, and we provide an overview of current data and metadata standards. Several challenges remain to be solved for building global EBV data products: (i) developing tools and models for combining heterogeneous, multi-source data sets and filling data gaps in geographic, temporal and taxonomic coverage, (ii) integrating emerging methods and technologies for data collection such as citizen science, sensor networks, DNA-based techniques and satellite remote sensing, (iii) solving major technical issues related to data product structure, data storage, execution of workflows and the production process/cycle as well as approaching technical interoperability among research infrastructures, (iv) allowing semantic interoperability by developing and adopting standards and tools for capturing consistent data and metadata, and (v) ensuring legal interoperability by endorsing open data or data that are free from restrictions on use, modification and sharing. Addressing these challenges is critical for biodiversity research and for assessing progress towards conservation policy targets and sustainable development goals. © 2017 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.

Conclusions about Niche Expansion in Introduced Impatiens walleriana Populations Depend on Method of Analysis

PubMed Central

Mandle, Lisa; Warren, Dan L.; Hoffmann, Matthias H.; Peterson, A. Townsend; Schmitt, Johanna; von Wettberg, Eric J.

2010-01-01

Determining the degree to which climate niches are conserved across plant species' native and introduced ranges is valuable to developing successful strategies to limit the introduction and spread of invasive plants, and also has important ecological and evolutionary implications. Here, we test whether climate niches differ between native and introduced populations of Impatiens walleriana, globally one of the most popular horticultural species. We use approaches based on both raw climate data associated with occurrence points and ecological niche models (ENMs) developed with Maxent. We include comparisons of climate niche breadth in both geographic and environmental spaces, taking into account differences in available habitats between the distributional areas. We find significant differences in climate envelopes between native and introduced populations when comparing raw climate variables, with introduced populations appearing to expand into wetter and cooler climates. However, analyses controlling for differences in available habitat in each region do not indicate expansion of climate niches. We therefore cannot reject the hypothesis that observed differences in climate envelopes reflect only the limited environments available within the species' native range in East Africa. Our results suggest that models built from only native range occurrence data will not provide an accurate prediction of the potential for invasiveness if applied to areas containing a greater range of environmental combinations, and that tests of niche expansion may overestimate shifts in climate niches if they do not control carefully for environmental differences between distributional areas. PMID:21206912

Recent introduction and recombination in Colletotrichum acutatum populations associated with citrus postbloom fruit drop epidemics in São Paulo, Brazil.

PubMed

Ciampi-Guillardi, Maisa; Baldauf, Cristina; Souza, Anete Pereira; Silva-Junior, Geraldo José; Amorim, Lilian

2014-07-01

Citrus crops in São Paulo State, Brazil, have been severely affected by postbloom fruit drop disease (PFD), which is caused by Colletotrichum acutatum. This disease leads to the drop of up to 100% of young fruits. Previous studies have assumed that this pathogen exhibits a clonal reproductive mode, although no population genetic studies have been conducted so far. Thus, the genetic structure of six C. acutatum populations from sweet orange orchards showing PFD symptoms was determined using nine microsatellite markers, enabling inference on predominant mode of reproduction. C. acutatum populations exhibit a nearly panmictic genetic structure and a high degree of admixture, indicating either ongoing contemporary gene flow at a regional scale or a recent introduction from a common source, since this pathogen was introduced in Brazil only very recently. Sharing haplotypes among orchards separated by 400 km suggests the natural dispersal of fungal propagules, with the possible involvement of pollinators. A significant population expansion was detected, which was consistent with an increase in host density associated with crop expansion toward new areas across the state. Findings of moderate to high levels of haplotypic diversity and gametic equilibrium suggest that recombination might play an important role in these pathogen populations, possibly via parasexual reproduction or a cryptic sexual cycle. This study provides additional tools for epidemiological studies of C. acutatum to improve prevention and management strategies for this disease.

Phylogeography of recently emerged DENV-2 in southern Viet Nam.

PubMed

Rabaa, Maia A; Ty Hang, Vu Thi; Wills, Bridget; Farrar, Jeremy; Simmons, Cameron P; Holmes, Edward C

2010-07-27

Revealing the dispersal of dengue viruses (DENV) in time and space is central to understanding their epidemiology. However, the processes that shape DENV transmission patterns at the scale of local populations are not well understood, particularly the impact of such factors as human population movement and urbanization. Herein, we investigated trends in the spatial dynamics of DENV-2 transmission in the highly endemic setting of southern Viet Nam. Through a phylogeographic analysis of 168 full-length DENV-2 genome sequences obtained from hospitalized dengue cases from 10 provinces in southern Viet Nam, we reveal substantial genetic diversity in both urban and rural areas, with multiple lineages identified in individual provinces within a single season, and indicative of frequent viral migration among communities. Focusing on the recently introduced Asian I genotype, we observed particularly high rates of viral exchange between adjacent geographic areas, and between Ho Chi Minh City, the primary urban center of this region, and populations across southern Viet Nam. Within Ho Chi Minh City, patterns of DENV movement appear consistent with a gravity model of virus dispersal, with viruses traveling across a gradient of population density. Overall, our analysis suggests that Ho Chi Minh City may act as a source population for the dispersal of DENV across southern Viet Nam, and provides further evidence that urban areas of Southeast Asia play a primary role in DENV transmission. However, these data also indicate that more rural areas are also capable of maintaining virus populations and hence fueling DENV evolution over multiple seasons.

Analysis of genetic diversity and population structure of oil palm (Elaeis guineensis) from China and Malaysia based on species-specific simple sequence repeat markers.

PubMed

Zhou, L X; Xiao, Y; Xia, W; Yang, Y D

2015-12-08

Genetic diversity and patterns of population structure of the 94 oil palm lines were investigated using species-specific simple sequence repeat (SSR) markers. We designed primers for 63 SSR loci based on their flanking sequences and conducted amplification in 94 oil palm DNA samples. The amplification result showed that a relatively high level of genetic diversity was observed between oil palm individuals according a set of 21 polymorphic microsatellite loci. The observed heterozygosity (Ho) was 0.3683 and 0.4035, with an average of 0.3859. The Ho value was a reliable determinant of the discriminatory power of the SSR primer combinations. The principal component analysis and unweighted pair-group method with arithmetic averaging cluster analysis showed the 94 oil palm lines were grouped into one cluster. These results demonstrated that the oil palm in Hainan Province of China and the germplasm introduced from Malaysia may be from the same source. The SSR protocol was effective and reliable for assessing the genetic diversity of oil palm. Knowledge of the genetic diversity and population structure will be crucial for establishing appropriate management stocks for this species.

Intracolonial genetic variation in the scleractinian coral Seriatopora hystrix

NASA Astrophysics Data System (ADS)

Maier, E.; Buckenmaier, A.; Tollrian, R.; Nürnberger, B.

2012-06-01

In recent years, increasing numbers of studies revealed intraorganismal genetic variation, primarily in modular organisms like plants or colonial marine invertebrates. Two underlying mechanisms are distinguished: Mosaicism is caused by somatic mutation, whereas chimerism originates from allogeneic fusion. We investigated the occurrence of intracolonial genetic variation at microsatellite loci in five natural populations of the scleractinian coral Seriatopora hystrix on the Great Barrier Reef. This coral is a widely distributed, brooding species that is at present a target of intensive population genetic research on reproduction and dispersal patterns. From each of 155 S. hystrix colonies, either two or three samples were genotyped at five or six loci. Twenty-seven (~17%) genetically heterogeneous colonies were found. Statistical analyses indicated the occurrence of both mosaicism and chimerism. In most cases, intracolonial variation was found only at a single allele. Our analyses suggest that somatic mutations present a major source of genetic heterogeneity within a single colony. Moreover, we observed large, apparently stable chimeric colonies that harbored clearly distinct genotypes and contrast these findings with the patterns typically observed in laboratory-based experiments. We discuss the error that mosaicism and chimerism introduce into population genetic analyses.

Health Surveys Using Mobile Phones in Developing Countries: Automated Active Strata Monitoring and Other Statistical Considerations for Improving Precision and Reducing Biases

PubMed Central

Blynn, Emily; Ahmed, Saifuddin; Gibson, Dustin; Pariyo, George; Hyder, Adnan A

2017-01-01

In low- and middle-income countries (LMICs), historically, household surveys have been carried out by face-to-face interviews to collect survey data related to risk factors for noncommunicable diseases. The proliferation of mobile phone ownership and the access it provides in these countries offers a new opportunity to remotely conduct surveys with increased efficiency and reduced cost. However, the near-ubiquitous ownership of phones, high population mobility, and low cost require a re-examination of statistical recommendations for mobile phone surveys (MPS), especially when surveys are automated. As with landline surveys, random digit dialing remains the most appropriate approach to develop an ideal survey-sampling frame. Once the survey is complete, poststratification weights are generally applied to reduce estimate bias and to adjust for selectivity due to mobile ownership. Since weights increase design effects and reduce sampling efficiency, we introduce the concept of automated active strata monitoring to improve representativeness of the sample distribution to that of the source population. Although some statistical challenges remain, MPS represent a promising emerging means for population-level data collection in LMICs. PMID:28476726

Two new species of the Fusarium solani species complex isolated from compost and hibiscus (Hibiscus sp.).

PubMed

Šišić, Adnan; Al-Hatmi, Abdullah M S; Baćanović-Šišić, Jelena; Ahmed, Sarah A; Dennenmoser, Dominic; de Hoog, G Sybren; Finckh, Maria R

2018-03-22

Two new species in the Fusarium solani species complex (FSSC) are described and introduced. The new taxa are represented by German isolates CBS 142481 and CBS 142480 collected from commercial yard waste compost and vascular tissue of a wilting branch of hibiscus, respectively. The phylogenetic relationships of the collected strains to one another and within the FSSC were evaluated based on DNA sequences of 6 gene loci. Due to the limited sequence data available for reference strains in GenBank, however, a multi-gene phylogenetic analysis included partial sequences for the internal transcribed spacer region and intervening 5.8S nrRNA gene (ITS), translation elongation factor 1-alpha (tef1) and the RNA polymerase II second largest subunit (rpb2). Morphological and molecular phylogenetic data independently showed that these strains are distinct populations of the FSSC, nested within Clade 3. Thus, we introduce Fusarium stercicola and Fusarium witzenhausenense as novel species in the complex. In addition, 19 plant species of 7 legume genera were evaluated for their potential to host the newly described taxa. Eighteen plant species were successfully colonized, with 6 and 9 of these being symptomatic hosts for F. stercicola and F. witzenhausenense, respectively. As plants of the family Fabaceae are very distant to the originally sourced material from which the new taxa were recovered, our results suggest that F. stercicola and F. witzenhausenense are not host-specific and are ecologically fit to sustain stable populations in variety of habitats.

50 CFR 17.80 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (CONTINUED) ENDANGERED AND THREATENED WILDLIFE AND PLANTS Experimental Populations § 17.80 Definitions. (a) The term experimental population means an introduced and/or designated population (including any off... subpart but only when, and at such times as the population is wholly separate geographically from...

50 CFR 17.80 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (CONTINUED) ENDANGERED AND THREATENED WILDLIFE AND PLANTS Experimental Populations § 17.80 Definitions. (a) The term experimental population means an introduced and/or designated population (including any off... subpart but only when, and at such times as the population is wholly separate geographically from...

50 CFR 17.80 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (CONTINUED) ENDANGERED AND THREATENED WILDLIFE AND PLANTS Experimental Populations § 17.80 Definitions. (a) The term experimental population means an introduced and/or designated population (including any off... subpart but only when, and at such times as the population is wholly separate geographically from...

50 CFR 17.80 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (CONTINUED) ENDANGERED AND THREATENED WILDLIFE AND PLANTS Experimental Populations § 17.80 Definitions. (a) The term experimental population means an introduced and/or designated population (including any off... subpart but only when, and at such times as the population is wholly separate geographically from...

Theoretical value of pre-trade testing for Salmonella in Swedish cattle herds.

PubMed

Sternberg Lewerin, Susanna

2018-05-01

The Swedish Salmonella control programme includes mandatory action if Salmonella is detected in a herd. The aim of this study was to assess the relative value of different strategies for pre-movement testing of cattle. Three fictitious herds were included: dairy, beef and specialised calf-fattening. The yearly risks of introducing Salmonella with and without individual serological or bulk milk testing were assessed as well as the effects of sourcing animals from low-prevalence areas or reducing the number of source herds. The initial risk was highest for the calf-fattening herd and lowest for the beef herd. For the beef and dairy herds, the yearly risk of Salmonella introduction was reduced by about 75% with individual testing. Sourcing animals from low-prevalence areas reduced the risk by >99%. For the calf-fattening herd, the yearly risk was reduced by almost 50% by individual testing or sourcing animals from a maximum of five herds. The method was useful for illustrating effects of risk mitigation when introducing animals into a herd. Sourcing animals from low-risk areas (or herds) is more effective than single testing of individual animals or bulk milk. A comprehensive approach to reduce the risk of introducing Salmonella from source herds is justified. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evidence of a Native Northwest Atlantic COI Haplotype Clade in the Cryptogenic Colonial Ascidian Botryllus schlosseri.

PubMed

Yund, Philip O; Collins, Catherine; Johnson, Sheri L

2015-06-01

The colonial ascidian Botryllus schlosseri should be considered cryptogenic (i.e., not definitively classified as either native or introduced) in the Northwest Atlantic. Although all the evidence is quite circumstantial, over the last 15 years most research groups have accepted the scenario of human-mediated dispersal and classified B. schlosseri as introduced; others have continued to consider it native or cryptogenic. We address the invasion status of this species by adding 174 sequences to the growing worldwide database for the mitochondrial gene cytochrome c oxidase subunit I (COI) and analyzing 1077 sequences to compare genetic diversity of one clade of haplotypes in the Northwest Atlantic with two hypothesized source regions (the Northeast Atlantic and Mediterranean). Our results lead us to reject the prevailing view of the directionality of transport across the Atlantic. We argue that the genetic diversity patterns at COI are far more consistent with the existence of at least one haplotype clade in the Northwest Atlantic (and possibly a second) that substantially pre-dates human colonization from Europe, with this native North American clade subsequently introduced to three sites in Northeast Atlantic and Mediterranean waters. However, we agree with past researchers that some sites in the Northwest Atlantic have more recently been invaded by alien haplotypes, so that some populations are currently composed of a mixture of native and invader haplotypes. © 2015 Marine Biological Laboratory.

[Comparative analysis of Andean and Caribbean region health systems].

PubMed

Gómez-Camelo, Diana

2005-01-01

Carrying out a comparative analysis of Andean and Caribbean health systems contributing towards the general panorama of Andean and Caribbean region health care system experience. This study was aimed at carrying out a comparative analysis of health systems in Bolivia, Colombia, Ecuador, Peru, Venezuela, the Dominican Republic and Cuba between 1990 and 2004. Documentary information from secondary sources was used. Reform and changes during the aforementioned period were compared, as well as the systems' current configurations. Described typologies were used for studying the health systems. Different organisational designs were found for the systems: a national health system (NHS), segmented systems and systems based on mandatory insurance. The trend of reforms introduced in the 1990s and current proposals in almost all systems are directed towards adopting mandatory insurance via a basic packet of services and strengthening competition in providing services through a public and private mix. The organisation and structure of most systems studied have introduced and continue to introduce changes in line with international guidelines. The generality of these structures means that efforts must still be made to adopt designs strengthening them as instruments improving populations' quality of life. Comparative analysis is a tool leading to studying health systems and producing information which can nourish debate regarding current sector reform. This work took shape during the first approach to a comparative study of Andean region and Caribbean health systems.

Ethnicity and Population Structure in Personal Naming Networks

PubMed Central

Mateos, Pablo; Longley, Paul A.; O'Sullivan, David

2011-01-01

Personal naming practices exist in all human groups and are far from random. Rather, they continue to reflect social norms and ethno-cultural customs that have developed over generations. As a consequence, contemporary name frequency distributions retain distinct geographic, social and ethno-cultural patterning that can be exploited to understand population structure in human biology, public health and social science. Previous attempts to detect and delineate such structure in large populations have entailed extensive empirical analysis of naming conventions in different parts of the world without seeking any general or automated methods of population classification by ethno-cultural origin. Here we show how ‘naming networks’, constructed from forename-surname pairs of a large sample of the contemporary human population in 17 countries, provide a valuable representation of cultural, ethnic and linguistic population structure around the world. This innovative approach enriches and adds value to automated population classification through conventional national data sources such as telephone directories and electoral registers. The method identifies clear social and ethno-cultural clusters in such naming networks that extend far beyond the geographic areas in which particular names originated, and that are preserved even after international migration. Moreover, one of the most striking findings of this approach is that these clusters simply ‘emerge’ from the aggregation of millions of individual decisions on parental naming practices for their children, without any prior knowledge introduced by the researcher. Our probabilistic approach to community assignment, both at city level as well as at a global scale, helps to reveal the degree of isolation, integration or overlap between human populations in our rapidly globalising world. As such, this work has important implications for research in population genetics, public health, and social science adding new understandings of migration, identity, integration and social interaction across the world. PMID:21909399

Invasive hybridization in a threatened species is accelerated by climate change

USGS Publications Warehouse

Muhlfeld, Clint C.; Kovach, Ryan P.; Jones, Leslie A.; Al-Chokhachy, Robert K.; Boyer, Matthew C.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Allendorf, Fred W.

2014-01-01

Climate change will decrease worldwide biodiversity through a number of potential pathways, including invasive hybridization (cross-breeding between invasive and native species). How climate warming influences the spread of hybridization and loss of native genomes poses difficult ecological and evolutionary questions with little empirical information to guide conservation management decisions. Here we combine long-term genetic monitoring data with high-resolution climate and stream temperature predictions to evaluate how recent climate warming has influenced the spatio-temporal spread of human-mediated hybridization between threatened native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and non-native rainbow trout (Oncorhynchus mykiss), the world’s most widely introduced invasive fish. Despite widespread release of millions of rainbow trout over the past century within the Flathead River system, a large relatively pristine watershed in western North America, historical samples revealed that hybridization was prevalent only in one (source) population. During a subsequent 30-year period of accelerated warming, hybridization spread rapidly and was strongly linked to interactions between climatic drivers—precipitation and temperature—and distance to the source population. Specifically, decreases in spring precipitation and increases in summer stream temperature probably promoted upstream expansion of hybridization throughout the system. This study shows that rapid climate warming can exacerbate interactions between native and non-native species through invasive hybridization, which could spell genomic extinction for many species.

Mislabeling of an invasive vine (Celastrus orbiculatus) as a native congener (C. scandens) in horticulture

USGS Publications Warehouse

Zaya, David N.; Leicht-Young, Stacey A.; Pavlovic, Noel B.; Hetrea, Christopher S.; Ashley, Mary V.

2017-01-01

The horticultural industry is an important source of invasive ornamental plant species, which is part of the motivation for an increased emphasis on using native alternatives. We were interested in the possibility that plants marketed in the midwestern United States as the native Celastrus scandens, or American bittersweet, were actually the difficult-to-distinguish invasive Celastrus orbiculatus (oriental bittersweet) or hybrids of the two species. We used nuclear microsatellite DNA loci to compare the genetic identities of 34 plants from 11 vendors with reference plants from wild populations of known species identity. We found that 18 samples (53%) were mislabeled, and 7 of the 11 vendors sold mislabeled plants. Mislabeled plants were more likely to be purchased through Internet or phone order shipments and were significantly less expensive than accurately labeled plants. Vendors marketed mislabeled plants under five different cultivar names, as well as unnamed strains. Additionally, the most common native cultivar, ‘Autumn Revolution,’ displays reproductive characteristics that diverge from the typical C. scandens, which could be of some concern. The lower price and abundance of mislabeled invasive plants introduces incentives for consumers to unknowingly contribute to the spread of C. orbiculatus. Revealing the potential sources of C. orbiculatus is critical for controlling further spread of the invasive vine and limiting its impact on C. scandens populations.

Conspecific Plasticity and Invasion: Invasive Populations of Chinese Tallow (Triadica sebifera) Have Performance Advantage over Native Populations Only in Low Soil Salinity

PubMed Central

Chen, Leiyi; Tiu, Candice J.; Peng, Shaolin; Siemann, Evan

2013-01-01

Global climate change may increase biological invasions in part because invasive species may have greater phenotypic plasticity than native species. This may be especially important for abiotic stresses such as salt inundation related to increased hurricane activity or sea level rise. If invasive species indeed have greater plasticity, this may reflect genetic differences between populations in the native and introduced ranges. Here, we examined plasticity of functional and fitness-related traits of Chinese tallow (Triadica sebifera) populations from the introduced and native ranges that were grown along a gradient of soil salinity (control: 0 ppt; Low: 5 ppt; Medium: 10 ppt; High: 15 ppt) in a greenhouse. We used both norm reaction and plasticity index (PIv) to estimate the conspecific phenotypic plasticity variation between invasive and native populations. Overall, invasive populations had higher phenotypic plasticity of height growth rate (HGR), aboveground biomass, stem biomass and specific leaf area (SLA). The plasticity Index (PIv) of height growth rate (HGR) and SLA each were higher for plants from invasive populations. Absolute performance was always comparable or greater for plants from invasive populations versus native populations with the greatest differences at low stress levels. Our results were consistent with the “Master-of-some” pattern for invasive plants in which the fitness of introduced populations was greater in more benign conditions. This suggests that the greater conspecific phenotypic plasticity of invasive populations compared to native populations may increase invasion success in benign conditions but would not provide a potential interspecific competitive advantage in higher salinity soils that may occur with global climate change in coastal areas. PMID:24040366

Conspecific plasticity and invasion: invasive populations of Chinese tallow (Triadica sebifera) have performance advantage over native populations only in low soil salinity.

PubMed

Chen, Leiyi; Tiu, Candice J; Peng, Shaolin; Siemann, Evan

2013-01-01

Global climate change may increase biological invasions in part because invasive species may have greater phenotypic plasticity than native species. This may be especially important for abiotic stresses such as salt inundation related to increased hurricane activity or sea level rise. If invasive species indeed have greater plasticity, this may reflect genetic differences between populations in the native and introduced ranges. Here, we examined plasticity of functional and fitness-related traits of Chinese tallow (Triadica sebifera) populations from the introduced and native ranges that were grown along a gradient of soil salinity (control: 0 ppt; Low: 5 ppt; Medium: 10 ppt; High: 15 ppt) in a greenhouse. We used both norm reaction and plasticity index (PIv) to estimate the conspecific phenotypic plasticity variation between invasive and native populations. Overall, invasive populations had higher phenotypic plasticity of height growth rate (HGR), aboveground biomass, stem biomass and specific leaf area (SLA). The plasticity Index (PIv) of height growth rate (HGR) and SLA each were higher for plants from invasive populations. Absolute performance was always comparable or greater for plants from invasive populations versus native populations with the greatest differences at low stress levels. Our results were consistent with the "Master-of-some" pattern for invasive plants in which the fitness of introduced populations was greater in more benign conditions. This suggests that the greater conspecific phenotypic plasticity of invasive populations compared to native populations may increase invasion success in benign conditions but would not provide a potential interspecific competitive advantage in higher salinity soils that may occur with global climate change in coastal areas.

South American Plasmodium falciparum after the Malaria Eradication Era: Clonal Population Expansion and Survival of the Fittest Hybrids

PubMed Central

Griffing, Sean M.; Mixson-Hayden, Tonya; Sridaran, Sankar; Alam, Md Tauqeer; McCollum, Andrea M.; Cabezas, César; Marquiño Quezada, Wilmer; Barnwell, John W.; Macedo De Oliveira, Alexandre; Lucas, Carmen; Arrospide, Nancy; Escalante, Ananias A.; Bacon, David J.; Udhayakumar, Venkatachalam

2011-01-01

Malaria has reemerged in many regions where once it was nearly eliminated. Yet the source of these parasites, the process of repopulation, their population structure, and dynamics are ill defined. Peru was one of malaria eradication's successes, where Plasmodium falciparum was nearly eliminated for two decades. It reemerged in the 1990s. In the new era of malaria elimination, Peruvian P. falciparum is a model of malaria reinvasion. We investigated its population structure and drug resistance profiles. We hypothesized that only populations adapted to local ecological niches could expand and repopulate and originated as vestigial populations or recent introductions. We investigated the genetic structure (using microsatellites) and drug resistant genotypes of 220 parasites collected from patients immediately after peak epidemic expansion (1999–2000) from seven sites across the country. The majority of parasites could be grouped into five clonal lineages by networks and AMOVA. The distribution of clonal lineages and their drug sensitivity profiles suggested geographic structure. In 2001, artesunate combination therapy was introduced in Peru. We tested 62 parasites collected in 2006–2007 for changes in genetic structure. Clonal lineages had recombined under selection for the fittest parasites. Our findings illustrate that local adaptations in the post-eradication era have contributed to clonal lineage expansion. Within the shifting confluence of drug policy and malaria incidence, populations continue to evolve through genetic outcrossing influenced by antimalarial selection pressure. Understanding the population substructure of P. falciparum has implications for vaccine, drug, and epidemiologic studies, including monitoring malaria during and after the elimination phase. PMID:21949680

SLUG - stochastically lighting up galaxies - III. A suite of tools for simulated photometry, spectroscopy, and Bayesian inference with stochastic stellar populations

NASA Astrophysics Data System (ADS)

Krumholz, Mark R.; Fumagalli, Michele; da Silva, Robert L.; Rendahl, Theodore; Parra, Jonathan

2015-09-01

Stellar population synthesis techniques for predicting the observable light emitted by a stellar population have extensive applications in numerous areas of astronomy. However, accurate predictions for small populations of young stars, such as those found in individual star clusters, star-forming dwarf galaxies, and small segments of spiral galaxies, require that the population be treated stochastically. Conversely, accurate deductions of the properties of such objects also require consideration of stochasticity. Here we describe a comprehensive suite of modular, open-source software tools for tackling these related problems. These include the following: a greatly-enhanced version of the SLUG code introduced by da Silva et al., which computes spectra and photometry for stochastically or deterministically sampled stellar populations with nearly arbitrary star formation histories, clustering properties, and initial mass functions; CLOUDY_SLUG, a tool that automatically couples SLUG-computed spectra with the CLOUDY radiative transfer code in order to predict stochastic nebular emission; BAYESPHOT, a general-purpose tool for performing Bayesian inference on the physical properties of stellar systems based on unresolved photometry; and CLUSTER_SLUG and SFR_SLUG, a pair of tools that use BAYESPHOT on a library of SLUG models to compute the mass, age, and extinction of mono-age star clusters, and the star formation rate of galaxies, respectively. The latter two tools make use of an extensive library of pre-computed stellar population models, which are included in the software. The complete package is available at http://www.slugsps.com.

Helminth species richness of introduced and native grey mullets (Teleostei: Mugilidae).

PubMed

Sarabeev, Volodimir

2015-08-01

Quantitative complex analyses of parasite communities of invaders across different native and introduced populations are largely lacking. The present study provides a comparative analysis of species richness of helminth parasites in native and invasive populations of grey mullets. The local species richness differed between regions and host species, but did not differ when compared with invasive and native hosts. The size of parasite assemblages of endohelminths was higher in the Mediterranean and Azov-Black Seas, while monogeneans were the most diverse in the Sea of Japan. The helminth diversity was apparently higher in the introduced population of Liza haematocheilus than that in their native habitat, but this trend could not be confirmed when the size of geographic range and sampling efforts were controlled for. The parasite species richness at the infracommunity level of the invasive host population is significantly lower compared with that of the native host populations that lends support to the enemy release hypothesis. A distribution pattern of the infracommunity richness of acquired parasites by the invasive host can be characterized as aggregated and it is random in native host populations. Heterogeneity in the host susceptibility and vulnerability to acquired helminth species was assumed to be a reason of the aggregation of species numbers in the population of the invasive host. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Population Geography: Problems, Concepts, and Prospects.

ERIC Educational Resources Information Center

Peters, Gary L.; Larkin, Robert P.

This book introduces secondary students to population geography. Material from other disciplines is included because the study of population is multidisciplinary. It is presented in eleven chapters. The introduction considers definitions of concepts and aspects of population geography, explaining the emphasis on spatial patterns of population…

Does source population size affect performance in new environments?

PubMed Central

Yates, Matthew C; Fraser, Dylan J

2014-01-01

Small populations are predicted to perform poorly relative to large populations when experiencing environmental change. To explore this prediction in nature, data from reciprocal transplant, common garden, and translocation studies were compared meta-analytically. We contrasted changes in performance resulting from transplantation to new environments among individuals originating from different sized source populations from plants and salmonids. We then evaluated the effect of source population size on performance in natural common garden environments and the relationship between population size and habitat quality. In ‘home-away’ contrasts, large populations exhibited reduced performance in new environments. In common gardens, the effect of source population size on performance was inconsistent across life-history stages (LHS) and environments. When transplanted to the same set of new environments, small populations either performed equally well or better than large populations, depending on life stage. Conversely, large populations outperformed small populations within native environments, but only at later life stages. Population size was not associated with habitat quality. Several factors might explain the negative association between source population size and performance in new environments: (i) stronger local adaptation in large populations and antagonistic pleiotropy, (ii) the maintenance of genetic variation in small populations, and (iii) potential environmental differences between large and small populations. PMID:25469166

Population dynamics of hydrocarbon-oxidizing yeasts introduced into oil-contaminated soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kulichevskaya, I.S.; Panikov, N.S.; Guzev, V.S.

A pure culture of the yeastlike fungus Candida lipolytica, able to actively degrade crude oil, was isolated. In preliminary trials, an optimal dose for its introduction was adjusted (10{sup 8} cells/g soil) to ensure its predominance in contaminated soil. Laboratory incubation experiments in which the population dynamics of the introduced species and indigenous soil bacteria and the dynamics of soil respiration activity were followed showed that active proliferation of the introduced species in soil is accompanied by its elimination as a result of grazing by microfauna. The most favorable conditions for the development of introduced yeasts were found to bemore » provided in gray and gray forest soil, whereas in soddy-podzolic soil, their growth and oil degradation were retarded. The obtained results indicate that introduction of the tested culture can significantly increase the rate of oil degradation. In uncontaminated soil, the introduced species is rapidly eliminated. 9 refs., 5 figs.« less

40 CFR 467.65 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... sources. 467.65 Section 467.65 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Subcategory § 467.65 Pretreatment standards for existing sources. Except as provided in 40 CFR 403.7 and 403.13, any existing source subject to this subpart which introduces pollutants into a publicly owned...

The Population Reference Bureau's Population Handbook.

ERIC Educational Resources Information Center

Haupt, Arthur; Kane, Thomas T.

This handbook offers information on population dynamics. The population data resource is intended for use by journalists, policymakers, teachers, high school and college students, libraries, advertising agencies, and family planning groups. The document is presented in 12 sections. Section I introduces demography, explains the purpose and scope of…

Population Education in Africa. English Version.

ERIC Educational Resources Information Center

Sankale-Semeteys, Eva, Ed.

1985-01-01

National conferences on population and development have recommended the integration of population issues into development planning by national governments. This book presents several ideas of practitioners in the field of population and family life education. Five articles in Part I focus on solutions to problems of introducing population…

Probing the X-Ray Binary Populations of the Ring Galaxy NGC 1291

NASA Technical Reports Server (NTRS)

Luo, B.; Fabbiano, G.; Fragos, T.; Kim, D. W.; Belczynski, K.; Brassington, N. J.; Pellegrini, S.; Tzanavaris, P.; Wang, J.; Zezas, A.

2012-01-01

We present Chandra studies of the X-ray binary (XRB) populations in the bulge and ring regions of the ring galaxy NGC 1291. We detect 169 X-ray point sources in the galaxy, 75 in the bulge and 71 in the ring, utilizing the four available Chandra observations totaling an effective exposure of 179 ks. We report photometric properties of these sources in a point-source catalog. There are approx. 40% of the bulge sources and approx. 25% of the ring sources showing > 3(sigma) long-term variability in their X-ray count rate. The X-ray colors suggest that a significant fraction of the bulge (approx. 75%) and ring (approx. 65%) sources are likely low-mass X-ray binaries (LMXBs). The spectra of the nuclear source indicate that it is a low-luminosity AGN with moderate obscuration; spectral variability is observed between individual observations. We construct 0.3-8.0 keV X-ray luminosity functions (XLFs) for the bulge and ring XRB populations, taking into account the detection incompleteness and background AGN contamination. We reach 90% completeness limits of approx.1.5 x 10(exp 37) and approx. 2.2 x 10(exp 37) erg/s for the bulge and ring populations, respectively. Both XLFs can be fit with a broken power-law model, and the shapes are consistent with those expected for populations dominated by LMXBs. We perform detailed population synthesis modeling of the XRB populations in NGC 1291 , which suggests that the observed combined XLF is dominated by aD old LMXB population. We compare the bulge and ring XRB populations, and argue that the ring XRBs are associated with a younger stellar population than the bulge sources, based on the relative over-density of X-ray sources in the ring, the generally harder X-ray color of the ring sources, the overabundance of luminous sources in the combined XLF, and the flatter shape of the ring XLF.

Transatlantic invasion routes and adaptive potential in North American populations of the invasive glossy buckthorn, Frangula alnus

PubMed Central

De Kort, Hanne; Mergeay, Joachim; Jacquemyn, Hans; Honnay, Olivier

2016-01-01

Background and Aims Many invasive species severely threaten native biodiversity and ecosystem functioning. One of the most prominent questions in invasion genetics is how invasive populations can overcome genetic founder effects to establish stable populations after colonization of new habitats. High native genetic diversity and multiple introductions are expected to increase genetic diversity and adaptive potential in the invasive range. Our aim was to identify the European source populations of Frangula alnus (glossy buckthorn), an ornamental and highly invasive woody species that was deliberately introduced into North America at the end of the 18th century. A second aim of this study was to assess the adaptive potential as an explanation for the invasion success of this species. Methods Using a set of annotated single-nucleotide polymorphisms (SNPs) that were assigned a putative function based on sequence comparison with model species, a total of 38 native European and 21 invasive North American populations were subjected to distance-based structure and assignment analyses combined with population genomic tools. Genetic diversity at SNPs with ecologically relevant functions was considered as a proxy for adaptive potential. Key Results Patterns of invasion coincided with early modern transatlantic trading routes. Multiple introductions through transatlantic trade from a limited number of European port regions to American urban areas led to the establishment of bridgehead populations with high allelic richness and expected heterozygosity, allowing continuous secondary migration to natural areas. Conclusions Targeted eradication of the urban populations, where the highest genetic diversity and adaptive potential were observed, offers a promising strategy to arrest further invasion of native American prairies and forests. PMID:27539599

Mixed-source reintroductions lead to outbreeding depression in second-generation descendents of a native North American fish

USGS Publications Warehouse

Huff, D.D.; Miller, L.M.; Chizinski, C.J.; Vondracek, B.

2011-01-01

Reintroductions are commonly employed to preserve intraspecific biodiversity in fragmented landscapes. However, reintroduced populations are frequently smaller and more geographically isolated than native populations. Mixing genetically, divergent sources are often proposed to attenuate potentially low genetic diversity in reintroduced populations that may result from small effective population sizes. However, a possible negative tradeoff for mixing sources is outbreeding depression in hybrid offspring. We examined the consequences of mixed-source reintroductions on several fitness surrogates at nine slimy sculpin (Cottus cognatus) reintroduction sites in south-east Minnesota. We inferred the relative fitness of each crosstype in the reintroduced populations by comparing their growth rate, length, weight, body condition and persistence in reintroduced populations. Pure strain descendents from a single source population persisted in a greater proportion than expected in the reintroduced populations, whereas all other crosstypes occurred in a lesser proportion. Length, weight and growth rate were lower for second-generation intra-population hybrid descendents than for pure strain and first-generation hybrids. In the predominant pure strain, young-of the-year size was significantly greater than any other crosstype. Our results suggested that differences in fitness surrogates among crosstypes were consistent with disrupted co-adapted gene complexes associated with beneficial adaptations in these reintroduced populations. Future reintroductions may be improved by evaluating the potential for local adaptation in source populations or by avoiding the use of mixed sources by default when information on local adaptations or other genetic characteristics is lacking. ?? 2011 Blackwell Publishing Ltd.

Abundance of introduced species at home predicts abundance away in herbaceous communities

Treesearch

J. Firn; J.L. Moore; A.S. MacDougall; E.T. Borer; E.W. Seabloom; J. HilleRisLambers; S. Harpole; E.E. Cleland; C.S. Brown; J.M.H. Knops; S.M. Prober; D.A. Pyke; K.A. Farrell; J.D. Bakker; L.R. O’Halloran; P.B. Adler; S.L. Collins; C.M. D’Antonio; M.J. Crawley; E.M. Wolkovich; K.J. La Pierre; B.A. Melbourne; Y. Hautier; J.W. Morgan; A.D.B. Leakey; A.D. Kay; R.L. McCulley; K.F. Davies; C.J. Stevens; C.J. Chu

2011-01-01

Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at...

Interchange. Population Education Newsletter. Volume 5, Number 3.

ERIC Educational Resources Information Center

Seltzer, Judith; Fletcher, Carol

This publication is designed to introduce the interdisciplinary nature of population information to educators and centers of population education activity, provide classroom activity suggestions, and to review developments in the effort to infuse population issues into U.S. secondary schools. The publication provides a forum for information and…

Genetic variation in native populations of the laurel wilt pathogen, Raffaelea lauricola , in Taiwan and Japan and the introduced population in the United States

Treesearch

Caroline E. Wuest; Thomas C. Harrington; Stephen W. Fraedrich; Hye-Young Yun; Sheng-Shan Lu

2017-01-01

Laurel wilt is a vascular wilt disease caused by Raffaelea lauricola, a mycangial symbiont of an ambrosia beetle, Xyleborus glabratus. The fungus and vector are native to Asia but were apparently introduced to the Savannah, GA, area 15 or more years ago. Laurel wilt has caused widespread mortality on redbay (Persea borbonia) and other members of the Lauraceae in the...

Global phylogeography of the widely introduced North West Pacific ascidian Styela clava.

PubMed

Goldstien, Sharyn J; Dupont, Lise; Viard, Frédérique; Hallas, Paul J; Nishikawa, Teruaki; Schiel, David R; Gemmell, Neil J; Bishop, John D D

2011-02-22

The solitary ascidian Styela clava Herdman, 1882 is considered to be native to Japan, Korea, northern China and the Russian Federation in the NW Pacific, but it has spread globally over the last 80 years and is now established as an introduced species on the east and west coasts of North America, Europe, Australia and New Zealand. In eastern Canada it reaches sufficient density to be a serious pest to aquaculture concerns. We sequenced a fragment of the cytochrome oxidase subunit I mitochondrial gene (COI) from a total of 554 individuals to examine the genetic relationships of 20 S. clava populations sampled throughout the introduced and native ranges, in order to investigate invasive population characteristics. The data presented here show a moderate level of genetic diversity throughout the northern hemisphere. The southern hemisphere (particularly New Zealand) displays a greater amount of haplotype and nucleotide diversity in comparison. This species, like many other invasive species, shows a range of genetic diversities among introduced populations independent of the age of incursion. The successful establishment of this species appears to be associated with multiple incursions in many locations, while other locations appear to have experienced rapid expansion from a potentially small population with reduced genetic diversity. These contrasting patterns create difficulties when attempting to manage and mitigate a species that continues to spread among ports and marinas around the world.

DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas

NASA Astrophysics Data System (ADS)

Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

2016-09-01

The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change.

DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas

PubMed Central

Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

2016-01-01

The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change. PMID:27666088

DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas.

PubMed

Hsiao, Sheng-Tai; Chuang, Shin-Chang; Chen, Kao-Sung; Ho, Ping-Ho; Wu, Chi-Lun; Chen, Chaolun Allen

2016-09-26

The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change.

Energy production for environmental issues in Turkey

NASA Astrophysics Data System (ADS)

Yuksel, Ibrahim; Arman, Hasan; Halil Demirel, Ibrahim

2017-11-01

Due to the diversification efforts of energy sources, use of natural gas that was newly introduced into Turkish economy, has been growing rapidly. Turkey has large reserves of coal, particularly of lignite. The proven lignite reserves are 8.0 billion tons. The estimated total possible reserves are 30 billion tons. Turkey, with its young population and growing energy demand per person, its fast growing urbanization, and its economic development, has been one of the fast growing power markets of the world for the last two decades. It is expected that the demand for electric energy in Turkey will be 580 billion kWh by the year 2020. Turkey's electric energy demand is growing about 6-8% yearly due to fast economic growing. This paper deals with energy demand and consumption for environmental issues in Turkey.

Influence factors and forecast of carbon emission in China: structure adjustment for emission peak

NASA Astrophysics Data System (ADS)

Wang, B.; Cui, C. Q.; Li, Z. P.

2018-02-01

This paper introduced Principal Component Analysis and Multivariate Linear Regression Model to verify long-term balance relationships between Carbon Emissions and the impact factors. The integrated model of improved PCA and multivariate regression analysis model is attainable to figure out the pattern of carbon emission sources. Main empirical results indicate that among all selected variables, the role of energy consumption scale was largest. GDP and Population follow and also have significant impacts on carbon emission. Industrialization rate and fossil fuel proportion, which is the indicator of reflecting the economic structure and energy structure, have a higher importance than the factor of urbanization rate and the dweller consumption level of urban areas. In this way, some suggestions are put forward for government to achieve the peak of carbon emissions.

The urban health transition hypothesis: empirical evidence of an avian influenza Kuznets curve in Vietnam?

PubMed

Spencer, James Herbert

2013-04-01

The literature on development has focused on the concept of transition in understanding the emergent challenges facing poor but rapidly developing countries. Scholars have focused extensively on the health and urban transitions associated with this change and, in particular, its use for understanding emerging infectious diseases. However, few have developed explicit empirical measures to quantify the extent to which a transitions focus is useful for theory, policy, and practice. Using open source data on avian influenza in 2004 and 2005 and the Vietnam Census of Population and Housing, this paper introduces the Kuznets curve as a tool for empirically estimating transition and disease. Findings suggest that the Kuznets curve is a viable tool for empirically assessing the role of transitional dynamics in the emergence of new infectious diseases.

Population Problems, Teacher's Guide. Environmental Education Unit, Twelfth Grade Sociology.

ERIC Educational Resources Information Center

Little Rock School District, AR.

Human population growth and the implications of increasing population on the well-being of men and nations is examined in this twelfth grade curriculum guide which is part of a series for grades 4 through 12. The primary functions of the unit are to introduce the student to reasons for population growth, results of overextended populations, and…

Wolbachia infections in native and introduced populations of fire ants (Solenopsis spp.).

PubMed

Shoemaker, D D; Ross, K G; Keller, L; Vargo, E L; Werren, J H

2000-12-01

Wolbachia are cytoplasmically inherited bacteria that induce a variety of effects with fitness consequences on host arthropods, including cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. We report here the presence of Wolbachia in native South American populations of the fire ant Solenopsis invicta, but the apparent absence of the bacteria in introduced populations of this pest species in the USA. The Wolbachia strains in native S. invicta are of two divergent types (A and B), and the frequency of infection varies dramatically between geographical regions and social forms of this host. Survey data reveal that Wolbachia also are found in other native fire ant species within the Solenopsis saevissima species complex from South America, including S. richteri. This latter species also has been introduced in the USA, where it lacks Wolbachia. Sequence data reveal complete phylogenetic concordance between mtDNA haplotype in S. invicta and Wolbachia infection type (A or B). In addition, the mtDNA and associated group A Wolbachia strain in S. invicta are more closely related to the mtDNA and Wolbachia strain found in S. richteri than they are to the mtDNA and associated group B Wolbachia in S. invicta. These data are consistent with historical introgression of S. richteri cytoplasmic elements into S. invicta populations, resulting in enhanced infection and mtDNA polymorphisms in S. invicta. Wolbachia may have significant fitness effects on these hosts (either directly or by cytoplasmic incompatibility) and therefore these microbes potentially could be used in biological control programmes to suppress introduced fire ant populations.

Comparative study on the dynamics and performances of Apis mellifera jemenitica and imported hybrid honeybee colonies in southwestern Saudi Arabia.

PubMed

Al-Ghamdi, Ahmad A; Adgaba, Nuru; Tadesse, Yilma; Getachew, Awraris; Al-Maktary, Anwer A

2017-07-01

The aims of this study were to assess the seasonal population dynamics and evaluate the performance of Apis mellifera jemenitica (local bee) and introduced hybrid honeybee colonies in the lowlands and highlands of southwestern Saudi Arabia. Data regarding the performance and population dynamics parameters such as brood and adult bee population, amounts of stored pollen and nectar were gathered from the two races (25 colonies of each) for one year (April 2013 through March 2014), and statistically tested. The results indicated that at low lands, local bee colonies maintained relatively high brood and adult bee populations ( P  < 0.05) than introduced honeybee colonies and produced more ( P  < 0.05) honey. The local bee colonies were able to hoard three times more ( P  < 0.05) pollen and built more ( P  < 0.05) queen cells than introduced bees in both the low and highland areas. The annual survival rate of local bee colonies was almost double ( P  < 0.05) than that of introduced honeybee colonies. Moreover, local bees had greater ( P  < 0.05) adult bee and brood populations than imported, throughout the year. The relatively good performance of local colonies could be due to their long year's adaptation to cope with resource scarcity and unpredictable environmental conditions of the regions. The possible reasons for the dwindling of the imported hybrid colonies could be due to continuing to exhibit adaptive characteristics of their original that might not fit well with the new environment.

A general solution strategy of modified power method for higher mode solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Peng; Lee, Hyunsuk; Lee, Deokjung, E-mail: deokjung@unist.ac.kr

2016-01-15

A general solution strategy of the modified power iteration method for calculating higher eigenmodes has been developed and applied in continuous energy Monte Carlo simulation. The new approach adopts four features: 1) the eigen decomposition of transfer matrix, 2) weight cancellation for higher modes, 3) population control with higher mode weights, and 4) stabilization technique of statistical fluctuations using multi-cycle accumulations. The numerical tests of neutron transport eigenvalue problems successfully demonstrate that the new strategy can significantly accelerate the fission source convergence with stable convergence behavior while obtaining multiple higher eigenmodes at the same time. The advantages of the newmore » strategy can be summarized as 1) the replacement of the cumbersome solution step of high order polynomial equations required by Booth's original method with the simple matrix eigen decomposition, 2) faster fission source convergence in inactive cycles, 3) more stable behaviors in both inactive and active cycles, and 4) smaller variances in active cycles. Advantages 3 and 4 can be attributed to the lower sensitivity of the new strategy to statistical fluctuations due to the multi-cycle accumulations. The application of the modified power method to continuous energy Monte Carlo simulation and the higher eigenmodes up to 4th order are reported for the first time in this paper. -- Graphical abstract: -- Highlights: •Modified power method is applied to continuous energy Monte Carlo simulation. •Transfer matrix is introduced to generalize the modified power method. •All mode based population control is applied to get the higher eigenmodes. •Statistic fluctuation can be greatly reduced using accumulated tally results. •Fission source convergence is accelerated with higher mode solutions.« less

Rapid Monte Carlo Simulation of Gravitational Wave Galaxies

NASA Astrophysics Data System (ADS)

Breivik, Katelyn; Larson, Shane L.

2015-01-01

With the detection of gravitational waves on the horizon, astrophysical catalogs produced by gravitational wave observatories can be used to characterize the populations of sources and validate different galactic population models. Efforts to simulate gravitational wave catalogs and source populations generally focus on population synthesis models that require extensive time and computational power to produce a single simulated galaxy. Monte Carlo simulations of gravitational wave source populations can also be used to generate observation catalogs from the gravitational wave source population. Monte Carlo simulations have the advantes of flexibility and speed, enabling rapid galactic realizations as a function of galactic binary parameters with less time and compuational resources required. We present a Monte Carlo method for rapid galactic simulations of gravitational wave binary populations.

40 CFR 421.195 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Indium Subcategory Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average mg...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Indium... existing sources. The mass of wastewater pollutants in secondary indium process wastewater introduced into...

40 CFR 421.195 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Indium Subcategory Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average mg...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Indium... existing sources. The mass of wastewater pollutants in secondary indium process wastewater introduced into...

Phylogeographic, ancient DNA, fossil and morphometric analyses reveal ancient and modern introductions of a large mammal: the complex case of red deer (Cervus elaphus) in Ireland

NASA Astrophysics Data System (ADS)

Carden, Ruth F.; McDevitt, Allan D.; Zachos, Frank E.; Woodman, Peter C.; O'Toole, Peter; Rose, Hugh; Monaghan, Nigel T.; Campana, Michael G.; Bradley, Daniel G.; Edwards, Ceiridwen J.

2012-05-01

The problem of how and when the island of Ireland attained its contemporary fauna has remained a key question in understanding Quaternary faunal assemblages. We assessed the complex history and origins of the red deer (Cervus elaphus) in Ireland using a multi-disciplinary approach. Mitochondrial sequences of contemporary and ancient red deer (dating from c 30,000 to 1700 cal. yr BP) were compared to decipher possible source populations of red deer in Ireland, in addition to craniometric analyses of skulls from candidate regions to distinguish between different colonization scenarios. Radiocarbon dating was undertaken on all bone fragments that were previously undated. Finally, a comprehensive review of the scientific literature, unpublished reports and other sources of data were also searched for red deer remains within Irish palaeontological and archaeological contexts. Despite being present in Ireland prior to the Last Glacial Maximum (LGM), there is a notable scarcity of red deer from the Younger Dryas stadial period until the Neolithic. The presence of red deer in Irish archaeological sites then occurs more frequently relative to other species. One population in the southwest of Ireland (Co. Kerry) shared haplotypes with the ancient Irish specimens and molecular dating and craniometric analysis suggests its persistence in Ireland since the Neolithic period. The synthesis of the results from this multi-disciplinary study all indicate that red deer were introduced by humans during the Irish Neolithic period and that one of these populations persists today. In conjunction with recent results from other species, Neolithic people from Ireland's nearest landmass, Britain, played a vital role in establishing its contemporary fauna and flora.

The global 21-cm signal in the context of the high- z galaxy luminosity function

NASA Astrophysics Data System (ADS)

Mirocha, Jordan; Furlanetto, Steven R.; Sun, Guochao

2017-01-01

We build a new model for the global 21-cm signal that is calibrated to measurements of the high-z galaxy luminosity function (LF) and further tuned to match the Thomson scattering optical depth of the cosmic microwave background, τe. Assuming that the z ≲ 8 galaxy population can be smoothly extrapolated to higher redshifts, the recent decline in best-fitting values of τe and the inefficient heating induced by X-ray binaries (the presumptive sources of the high-z X-ray background) imply that the entirety of cosmic reionization and reheating occurs at z ≲ 12. In contrast to past global 21-cm models, whose z ˜ 20 (ν ˜ 70 MHz) absorption features and strong ˜25 mK emission features were driven largely by the assumption of efficient early star formation and X-ray heating, our new models peak in absorption at ν ˜ 110 MHz at depths ˜-160 mK and have negligible emission components. Current uncertainties in the faint-end of the LF, binary populations in star-forming galaxies, and UV and X-ray escape fractions introduce ˜20 MHz (˜50 mK) deviations in the trough's frequency (amplitude), while emission signals remain weak (≲10 mK) and are confined to ν ≳ 140 MHz. These predictions, which are intentionally conservative, suggest that the detection of a 21-cm absorption minimum at frequencies below ˜90 MHz and/or emission signals stronger than ˜10mK at ν ≲ 140 MHz would provide strong evidence for `new' sources at high redshifts, such as Population III stars and their remnants.

Acrylamide in food products - eating habits and consumer awareness among Medical School students.

PubMed

Kowalska, Małgorzata; Żbikowska, Anna; Onacik-Gür, Sylwia; Kowalska, Dorota

2017-12-23

Acrylamide is formed in several foods during high-temperature processing. In view of reports written about the neurotoxic, genotoxic and carcinogenic effects of acrylamide, it was considered that the presence of this substance in food products might pose a risk for human health. Currently, according to EU Commission recommendations, the content of acrylamide in food should be monitored. The aim of this work was to analyze the food preferences of youth and students from medical schools in Radom, central-eastern Poland, as the most frequent precipitantsas in the field of food products that may be a significant source of acrylamide in the diet. Furthermore, an attempt was made to determine the level of knowledge of the population in the field of acrylamide. The research was conducted by questionnaire. The study was based on the answers of 227 respondents. The survey was carried out by direct contact with an interviewer from February - June 2012. Analysis of the study population shows that women consume more coffee than men. In addition, adults over 25 years old consumed the largest quantity of coffee; it can therefore be assumed that it is a significant source of acrylamide in their bodies. However, even young people under 17 declared that they consume coffee every day (20%). Due to the adverse effects of this compound it is important to reduce the level of acrylamide in food products. A few people in the population (7%) had heard of acrylamide previously, but none of them had any knowledge of its occurrence and formation. It is necessary to take strong action to change attitudes towards acrylamide and attempt to introduce ways to reduce this compound in the diet, for example, by appropriate selection of products in the daily diet and appropriate means of thermal preparation of products at home.

The Brown Tree Snake on Guam: How the Arrival of One Invasive Species Damaged the Ecology, Commerce, Electrical Systems and Human Health on Guam: A Comprehensive Information Source

USGS Publications Warehouse

Fritts, Thomas H.; Leasman-Tanner, Dawn

2001-01-01

Synopsis -- Shortly after World War II, and before 1952, the brown tree snake was accidentally transported from its native range in the South Pacific to Guam, probably as a stowaway in ship cargo. As a result of abnormally abundant prey resources on Guam and the absence of natural predators and other population controls, brown tree snake populations reached unprecedented numbers. Snakes caused the extirpation of most of the native forest vertebrate species; thousands of power outages affecting private, commercial, and military activities; widespread loss of domestic birds and pets; and considerable emotional trauma to residents and visitors alike when snakes invaded human habitats with the potential for severe envenomation of small children. Since Guam is a major transportation hub in the Pacific, numerous opportunities exist for the brown tree snakes on Guam to be introduced accidentally to other Pacific islands as passive stowaways in ship and air traffic from Guam. Numerous sightings of this species have been reported on other islands, and an incipient population is probably established on Saipan. It is important that people who may come in contact with the brown tree snake, particularly on neighboring islands and other high-risk sites, understand the scope of this problem and how to identify the snake so proper action can be taken. This resource has been developed to provide source materials on the history of the invasion, continuing threats, research results, and containment and management of the brown tree snake (Boiga irregularis) in Guam and its relevance to other islands and mild continental environments.

Phylogeography of Recently Emerged DENV-2 in Southern Viet Nam

PubMed Central

Rabaa, Maia A.; Ty Hang, Vu Thi; Wills, Bridget; Farrar, Jeremy; Simmons, Cameron P.; Holmes, Edward C.

2010-01-01

Revealing the dispersal of dengue viruses (DENV) in time and space is central to understanding their epidemiology. However, the processes that shape DENV transmission patterns at the scale of local populations are not well understood, particularly the impact of such factors as human population movement and urbanization. Herein, we investigated trends in the spatial dynamics of DENV-2 transmission in the highly endemic setting of southern Viet Nam. Through a phylogeographic analysis of 168 full-length DENV-2 genome sequences obtained from hospitalized dengue cases from 10 provinces in southern Viet Nam, we reveal substantial genetic diversity in both urban and rural areas, with multiple lineages identified in individual provinces within a single season, and indicative of frequent viral migration among communities. Focusing on the recently introduced Asian I genotype, we observed particularly high rates of viral exchange between adjacent geographic areas, and between Ho Chi Minh City, the primary urban center of this region, and populations across southern Viet Nam. Within Ho Chi Minh City, patterns of DENV movement appear consistent with a gravity model of virus dispersal, with viruses traveling across a gradient of population density. Overall, our analysis suggests that Ho Chi Minh City may act as a source population for the dispersal of DENV across southern Viet Nam, and provides further evidence that urban areas of Southeast Asia play a primary role in DENV transmission. However, these data also indicate that more rural areas are also capable of maintaining virus populations and hence fueling DENV evolution over multiple seasons. PMID:20668540

A Method for the Analysis of Information Use in Source-Based Writing

ERIC Educational Resources Information Center

Sormunen, Eero; Heinstrom, Jannica; Romu, Leena; Turunen, Risto

2012-01-01

Introduction: Past research on source-based writing assignments has hesitated to scrutinize how students actually use information afforded by sources. This paper introduces a method for the analysis of text transformations from sources to texts composed. The method is aimed to serve scholars in building a more detailed understanding of how…

40 CFR 421.46 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Copper Smelting... wastewater pollutants in primary copper smelting process wastewater introduced into a POTW shall not exceed...

40 CFR 421.66 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Copper Subcategory... wastewater pollutants in secondary copper process wastewater introduced into a POTW shall not exceed the...

40 CFR 421.66 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Copper Subcategory... wastewater pollutants in secondary copper process wastewater introduced into a POTW shall not exceed the...

40 CFR 421.46 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Copper Smelting... wastewater pollutants in primary copper smelting process wastewater introduced into a POTW shall not exceed...

The new flora of the northeastern USA: quantifying introduced plant species occupancy in forest ecosystems

Treesearch

Bethany K. Schulz; Andrew N. Gray

2013-01-01

Introduced plant species have significant negative impacts in many ecosystems and are found in many forests around the world. Some factors linked to the distribution of introduced species include fragmentation and disturbance, native species richness, and climatic and physical conditions of the landscape. However, there are few data sources that enable the assessment...

Multisource least-squares reverse-time migration with structure-oriented filtering

NASA Astrophysics Data System (ADS)

Fan, Jing-Wen; Li, Zhen-Chun; Zhang, Kai; Zhang, Min; Liu, Xue-Tong

2016-09-01

The technology of simultaneous-source acquisition of seismic data excited by several sources can significantly improve the data collection efficiency. However, direct imaging of simultaneous-source data or blended data may introduce crosstalk noise and affect the imaging quality. To address this problem, we introduce a structure-oriented filtering operator as preconditioner into the multisource least-squares reverse-time migration (LSRTM). The structure-oriented filtering operator is a nonstationary filter along structural trends that suppresses crosstalk noise while maintaining structural information. The proposed method uses the conjugate-gradient method to minimize the mismatch between predicted and observed data, while effectively attenuating the interference noise caused by exciting several sources simultaneously. Numerical experiments using synthetic data suggest that the proposed method can suppress the crosstalk noise and produce highly accurate images.

Hybridization and restricted gene flow between native and introduced stocks of Alpine whitefish (Coregonus sp.) across multiple environments

PubMed Central

Winkler, Kathrin A; Pamminger-Lahnsteiner, Barbara; Wanzenböck, Josef; Weiss, Steven

2011-01-01

Translocations of Baltic whitefish (Coregonus sp.) into Austrian Alpine lakes have created ‘artificial hybrid zones’, threatening the genetic integrity of native lineages. We evaluate the genetic structure of Coregonus in Austrian lakes and characterize hybridization and introgression between native and introduced lineages. Fifteen populations (N= 747) were assessed for allelic variation at eight microsatellite loci and a reduced set (N= 253) for variation across two mtDNA genes (cyt b and NADH-3). Bayesian approaches were used to estimate individual admixture proportions (q-values) and classify genotypes as native, introduced or hybrids. q-value distributions varied among populations highlighting differential hybridization and introgression histories. Many lakes revealed a clear distinction between native and introduced genotypes despite hybridization, whereas some locations revealed hybrid swarms. Genetic structure among lakes was congruent with morphological divergence and novelty raising speculation of multiple taxa, including a population south of the Alps, outside the putative native range of Coregonus. Although statistically congruent with inferences based on nuclear markers, mitochondrial haplotype data was not diagnostic with respect to native and non-native lineages, supporting that the Alpine region was colonized post-glacially by an admixture of mtDNA lineages, which coalesce >1 Ma. Mechanisms promoting or eroding lineage isolation are discussed, as well as a high potential to conserve native Alpine lineages despite the extensive historical use of introduced Baltic stocks. PMID:21199024

Losing a battle but winning the war: moving past preference-performance to understand native herbivore-novel host plant interactions.

PubMed

Brown, Leone M; Breed, Greg A; Severns, Paul M; Crone, Elizabeth E

2017-02-01

Introduced plants can positively affect population viability by augmenting the diet of native herbivores, but can negatively affect populations if they are subpar or toxic resources. In organisms with complex life histories, such as insects specializing on host plants, the impacts of a novel host may differ across life stages, with divergent effects on population persistence. Most research on effects of novel hosts has focused on adult oviposition preference and larval performance, but adult preference may not optimize offspring performance, nor be indicative of host quality from a demographic perspective. We compared population growth rates of the Baltimore checkerspot butterfly, Euphydryas phaeton, on an introduced host, Plantago lanceolata (English plantain), and the native host Chelone glabra (white turtlehead). Contrary to the previous findings suggesting that P. lanceolata could be a population sink, we found higher population growth rates (λ) on the introduced than the native host, even though some component parameters of λ were higher on the native host. Our findings illustrate the importance of moving beyond preference-performance studies to integrate vital rates across all life stages for evaluating herbivore-host plant relationships. Single measures of preference or performance are not sufficient proxies for overall host quality nor do they provide insights into longer term consequences of novel host plant use. In our system, in particular, P. lanceolata may buffer checkerspot populations when the native host is limiting, but high growth rates could lead to crashes over longer time scales.

How Influenza Vaccination Policy May affect Vaccine Logistics

PubMed Central

Assi, Tina-Marie; Rookkapan, Korngamon; Rajgopal, Jayant; Sornsrivichai, Vorasith; Brown, Shawn T.; Welling, Joel S.; Norman, Bryan A.; Connor, Diana L.; Chen, Sheng-I; Slayton, Rachel B.; Laosiritaworn, Yongjua; Wateska, Angela R.; Wisniewski, Stephen R.; Lee, Bruce Y.

2012-01-01

Background When policymakers make decision about the target populations and timing of influenza vaccination, they may not consider the impact on the vaccine supply chains, which may in turn affect vaccine availability. Purpose Our goal is to explore the effects on the Thailand vaccine supply chain of introducing influenza vaccines and varying the target populations and immunization time-frames. Methods Utilized our custom-designed software HERMES (Highly Extensible Resource for Modeling Supply Chains), we developed a detailed, computational discrete-event simulation model of the Thailand's National Immunization Program (NIP) supply chain in Trang Province, Thailand., A suite of experiments simulated introducing influenza vaccines for different target populations and over different time-frames prior to and during the annual influenza season. Results Introducing influenza vaccines creates bottlenecks that reduce the availability of both influenza vaccines as well as the other NIP vaccines, with provincial to district transport capacity being the primary constraint. Even covering only 25% of the Advisory Committee on Immunization Practice-recommended population while administering the vaccine over six months hinders overall vaccine availability so that only 62% of arriving patients can receive vaccines. Increasing the target population from 25% to 100% progressively worsens these bottlenecks, while increasing influenza vaccination time - frame from 1 to 6 months decreases these bottlenecks. Conclusion Since the choice of target populations for influenza vaccination and the time-frame to deliver this vaccine can substantially affect the flow of all vaccines, policy-makers may want to consider supply chain effects when choosing target populations for a vaccine. PMID:22537993

Characterization of the near-source population around five ...

EPA Pesticide Factsheets

Many ports are currently preparing for increased freight traffic, which may result in elevated local air pollution in areas near the port and freight transportation corridors. In this study, a geographical information system (GIS) analysis of areas surrounding five ports – Port of New York and New Jersey, Port of Virginia, Port of Savannah, Port of Miami, and Port of Houston – was conducted to characterize the population that might be affected by air emissions from the freight transportation network and to determine which sources had the potential to affect the most people. Defining “near-source” populations as living within 300 m of the freight transportation network, namely the port and associated truck routes, railroads, and intermodal facilities (e. g. rail yards and warehouses); near-source populations ranged from 37,000 to over a million within 10 km of a port. At the ports considered, the population living within 300 m of the port boundary constituted <10 % of the total near-source population. Sensitive population exposure was also indicated, such as the 81 day care centers and K-12 schools in near-source environments within 2 km of the Port of New York and New Jersey. Minority groups constituted 55 % to 85 % of the near-source populations in the five port areas. For four of the five ports, the mean and median income of the near-source population was lower and the minority percentage was higher than the population living adjacent to the near-sou

[Meeting of calory and protein requirements in developing countries].

PubMed

Cremer, H D

1976-03-01

While we have definite ideas regarding the requirements for energy and proteins, we have to rely on statistical data whether these requirements are actually met. In spite of the common unreliability of these data, they serve as an useful indicator of the general situation. The supply of nutritional energy represents the average energy requirement for the populations of most developing countries. However, the insufficient supply of high grade protein remains the main nutritional problem of most of these countries. To solve these problems, the following possibilities exist: --Ensuring a sufficient calorie supply so that valuable protein is not wasted for the production of energy --Improving the supply of protein-rich staple food --Supplementing of food with local protien-rich products --Introducing lifestock only when the foodstuff available cannot be used directly for human consumption -- Improving the staple food, introducing higher grade strains of cereals --Producing protein-rich vegetable mixture from local foodstuff --Utilization of synthetic amino acids and of new protein sources. To meet the requirements for calories, and especially for hgih grade protein, is possible only by international and interdisciplinary efforts of all experts concerned with nutrition in any way.

Role Clarification Processes for Better Integration of Nurse Practitioners into Primary Healthcare Teams: A Multiple-Case Study

PubMed Central

D'Amour, Danielle; Contandriopoulos, Damien; Chouinard, Véronique; Dubois, Carl-Ardy

2014-01-01

Role clarity is a crucial issue for effective interprofessional collaboration. Poorly defined roles can become a source of conflict in clinical teams and reduce the effectiveness of care and services delivered to the population. Our objective in this paper is to outline processes for clarifying professional roles when a new role is introduced into clinical teams, that of the primary healthcare nurse practitioner (PHCNP). To support our empirical analysis we used the Canadian National Interprofessional Competency Framework, which defines the essential components for role clarification among professionals. A qualitative multiple-case study was conducted on six cases in which the PHCNP role was introduced into primary care teams. Data collection included 34 semistructured interviews with key informants involved in the implementation of the PHCNP role. Our results revealed that the best performing primary care teams were those that used a variety of organizational and individual strategies to carry out role clarification processes. From this study, we conclude that role clarification is both an organizational process to be developed and a competency that each member of the primary care team must mobilize to ensure effective interprofessional collaboration. PMID:25692039

Role clarification processes for better integration of nurse practitioners into primary healthcare teams: a multiple-case study.

PubMed

Brault, Isabelle; Kilpatrick, Kelley; D'Amour, Danielle; Contandriopoulos, Damien; Chouinard, Véronique; Dubois, Carl-Ardy; Perroux, Mélanie; Beaulieu, Marie-Dominique

2014-01-01

Role clarity is a crucial issue for effective interprofessional collaboration. Poorly defined roles can become a source of conflict in clinical teams and reduce the effectiveness of care and services delivered to the population. Our objective in this paper is to outline processes for clarifying professional roles when a new role is introduced into clinical teams, that of the primary healthcare nurse practitioner (PHCNP). To support our empirical analysis we used the Canadian National Interprofessional Competency Framework, which defines the essential components for role clarification among professionals. A qualitative multiple-case study was conducted on six cases in which the PHCNP role was introduced into primary care teams. Data collection included 34 semistructured interviews with key informants involved in the implementation of the PHCNP role. Our results revealed that the best performing primary care teams were those that used a variety of organizational and individual strategies to carry out role clarification processes. From this study, we conclude that role clarification is both an organizational process to be developed and a competency that each member of the primary care team must mobilize to ensure effective interprofessional collaboration.

Evaluating acoustic speaker normalization algorithms: evidence from longitudinal child data.

PubMed

Kohn, Mary Elizabeth; Farrington, Charlie

2012-03-01

Speaker vowel formant normalization, a technique that controls for variation introduced by physical differences between speakers, is necessary in variationist studies to compare speakers of different ages, genders, and physiological makeup in order to understand non-physiological variation patterns within populations. Many algorithms have been established to reduce variation introduced into vocalic data from physiological sources. The lack of real-time studies tracking the effectiveness of these normalization algorithms from childhood through adolescence inhibits exploration of child participation in vowel shifts. This analysis compares normalization techniques applied to data collected from ten African American children across five time points. Linear regressions compare the reduction in variation attributable to age and gender for each speaker for the vowels BEET, BAT, BOT, BUT, and BOAR. A normalization technique is successful if it maintains variation attributable to a reference sociolinguistic variable, while reducing variation attributable to age. Results indicate that normalization techniques which rely on both a measure of central tendency and range of the vowel space perform best at reducing variation attributable to age, although some variation attributable to age persists after normalization for some sections of the vowel space. © 2012 Acoustical Society of America

Comparative Analyses of Plastid Sequences between Native and Introduced Populations of Aquatic Weeds Elodea canadensis and E. nuttallii

PubMed Central

Huotari, Tea; Korpelainen, Helena

2013-01-01

Non-indigenous species (NIS) are species living outside their historic or native range. Invasive NIS often cause severe environmental impacts, and may have large economical and social consequences. Elodea (Hydrocharitaceae) is a New World genus with at least five submerged aquatic angiosperm species living in fresh water environments. Our aim was to survey the geographical distribution of cpDNA haplotypes within the native and introduced ranges of invasive aquatic weeds Elodea canadensis and E. nuttallii and to reconstruct the spreading histories of these invasive species. In order to reveal informative chloroplast (cp) genome regions for phylogeographic analyses, we compared the plastid sequences of native and introduced individuals of E. canadensis. In total, we found 235 variable sites (186 SNPs, 47 indels and two inversions) between the two plastid sequences consisting of 112,193 bp and developed primers flanking the most variable genomic areas. These 29 primer pairs were used to compare the level and pattern of intraspecific variation within E. canadensis to interspecific variation between E. canadensis and E. nuttallii. Nine potentially informative primer pairs were used to analyze the phylogeographic structure of both Elodea species, based on 70 E. canadensis and 25 E. nuttallii individuals covering native and introduced distributions. On the whole, the level of variation between the two Elodea species was 53% higher than that within E. canadensis. In our phylogeographic analysis, only a single haplotype was found in the introduced range in both species. These haplotypes H1 (E. canadensis) and A (E. nuttallii) were also widespread in the native range, covering the majority of native populations analyzed. Therefore, we were not able to identify either the geographic origin of the introduced populations or test the hypothesis of single versus multiple introductions. The divergence between E. canadensis haplotypes was surprisingly high, and future research may clarify mechanisms that structure native E. canadensis populations. PMID:23620722

Application of Water Quality Model of Jordan River to Evaluate Climate Change Effects on Eutrophication

NASA Astrophysics Data System (ADS)

Van Grouw, B.

2016-12-01

The Jordan River is a 51 mile long freshwater stream in Utah that provides drinking water to more than 50% of Utah's population. The various point and nonpoint sources introduce an excess of nutrients into the river. This excess induces eutrophication that results in an inhabitable environment for aquatic life is expected to be exacerbated due to climate change. Adaptive measures must be evaluated based on predictions of climate variation impacts on eutrophication and ecosystem processes in the Jordan River. A Water Quality Assessment Simulation Program (WASP) model was created to analyze the data results acquired from a Total Maximum Daily Load (TMDL) study conducted on the Jordan River. Eutrophication is modeled based on levels of phosphates and nitrates from point and nonpoint sources, temperature, and solar radiation. It will simulate the growth of phytoplankton and periphyton in the river. This model will be applied to assess how water quality in the Jordan River is affected by variations in timing and intensity of spring snowmelt and runoff during drought in the valley and the resulting effects on eutrophication in the river.

The Use of the Free, Open-Source Program Jmol To Generate an Interactive Web Site To Teach Molecular Symmetry

NASA Astrophysics Data System (ADS)

Cass, Marion E.; Rzepa, Henry S.

2005-11-01

Illustrating and manipulating molecules in three dimensions are some of the truly wonderful advantages that computer technologies offer to chemistry teachers. In the following article we discuss our use of the program Jmol for the presentation of interactive materials to teach molecular symmetry. Jmol is an open-source code program that is free to all users and thus ideally suited for the development of teaching materials. Three primary pedagogic goals have been at the forefront in the development of our site. Our first goal was to animate symmetry operations and include interactive tools. Our second goal was to provide a library of molecules for student exercises to supplement their study of symmetry, using generic HTML templates populated using automatic tools based on Javascript. Our third goal in the development of our site was to include International Chemical Identifiers (InChIs) for each molecule to introduce students and educators to a new mechanism for identifying molecular resources and enabling their discovery using the Web search engines.

40 CFR 424.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Open Electric Furnaces With Wet Air... subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment...

40 CFR 424.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Open Electric Furnaces With Wet Air... subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment...

40 CFR 424.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Open Electric Furnaces With Wet Air... subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment...

40 CFR 424.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Open Electric Furnaces With Wet Air... subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment...

40 CFR 415.474 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2011 CFR

2011-07-01

... sulfate, nickel chloride, nickel nitrate, or nickel fluoborate which introduces pollutants into a publicly... for existing sources (PSES): Subpart AU—Nickel Sulfate, Nickel Chloride, Nickel Nitrate, Nickel...

Comparative Genetic Structure and Demographic History in Endemic Galápagos Weevils

PubMed Central

Stepien, Courtney C.; Sijapati, Manisha; Roque Albelo, Lázaro

2012-01-01

The challenge of maintaining genetic diversity within populations can be exacerbated for island endemics if they display population dynamics and behavioral attributes that expose them to genetic drift without the benefits of gene flow. We assess patterns of the genetic structure and demographic history in 27 populations of 9 species of flightless endemic Galápagos weevils from 9 of the islands and 1 winged introduced close relative. Analysis of mitochondrial DNA reveals a significant population structure and moderately variable, though demographically stable, populations for lowland endemics (FST = 0.094–0.541; π: 0.014–0.042; Mismatch P = 0.003–0.026; and D(Tajima) = −0.601 to 1.203), in contrast to signals of past contractions and expansions in highland specialists on 2 islands (Mismatch P = 0.003–0.026 and D(Tajima) = −0.601 to 1.203). We interpret this series of variable and highly structured population groups as a system of long-established, independently founded island units, where structuring could be a signal of microallopatric differentiation due to patchy host plant distribution and poor dispersal abilities. We suggest that the severe reduction and subsequent increase of a suitably moist habitat that accompanied past climatic variation could have contributed to the observed population fluctuations in highland specialists. We propose the future exploration of hybridization between the introduced and highland endemic species on Santa Cruz, especially given the expansion of the introduced species into the highlands, the sensitivity to past climatic variation detected in highland populations, and the potentially threatened state of single-island endemics. PMID:22174444

Diversity of introduced terrestrial flatworms in the Iberian Peninsula: a cautionary tale

PubMed Central

Álvarez-Presas, Marta; Tudó, Àngels; Jones, Hugh; Riutort, Marta

2014-01-01

Many tropical terrestrial planarians (Platyhelminthes, Geoplanidae) have been introduced around the globe. One of these species is known to cause significant decline in earthworm populations, resulting in a reduction of ecological functions that earthworms provide. Flatworms, additionally, are a potential risk to other species that have the same dietary needs. Hence, the planarian invasion might cause significant economic losses in agriculture and damage to the ecosystem. In the Iberian Peninsula only Bipalium kewense Moseley, 1878 had been cited till 2007. From that year on, four more species have been cited, and several reports of the presence of these animals in particular gardens have been received. In the present study we have: (1) analyzed the animals sent by non-specialists and also the presence of terrestrial planarians in plant nurseries and garden centers; (2) identified their species through morphological and phylogenetic molecular analyses, including representatives of their areas of origin; (3) revised their dietary sources and (4) used Species Distribution Modeling (SDM) for one species to evaluate the risk of its introduction to natural areas. The results have shown the presence of at least ten species of alien terrestrial planarians, from all its phylogenetic range. International plant trade is the source of these animals, and many garden centers are acting as reservoirs. Also, landscape restoration to reintroduce autochthonous plants has facilitated their introduction close to natural forests and agricultural fields. In conclusion, there is a need to take measures on plant trade and to have special care in the treatment of restored habitats. PMID:24949245

History and updating on the spread of Aedes albopictus in Italy.

PubMed

Romi, R

1995-12-01

The present distribution in Italy of Aedes albopictus, the Asian mosquito recently introduced, is described. Until now this mosquito species has been established in 8 regions of our country: Liguria, Veneto, Lazio, Lombardia, Emilia-Romagna, Toscana, Piemonte and recently Sardegna. The established populations have been able to overcome the winter season. These populations, certainly imported from temperate areas, have reconfirmed the great adaptation of the species, reaching the high latitude of 46 degrees North of the Padova area in Northern Italy. The origin of the infestation in Veneto region was shown to be strictly related to the importation of used tires and demonstrated at least for one load of tires from USA. The internal trading of tires from Veneto is the source of infestation of the other Italian regions, with the exception of Liguria and Lazio. Since the introduction and the establishment of Ae. albopictus in Italy represent a new problem of public health, a centre for the surveillance and control of this species has been set up at the Department of Parasitology, Istituto Superiore di Sanità, Roma.

One size does not fit all: investigating doctors' stated preference heterogeneity for job incentives to inform policy in Thailand.

PubMed

Lagarde, Mylene; Pagaiya, Nonglak; Tangcharoensathian, Viroj; Blaauw, Duane

2013-12-01

This study investigates heterogeneity in Thai doctors' job preferences at the beginning of their career, with a view to inform the design of effective policies to retain them in rural areas. A discrete choice experiment was designed and administered to 198 young doctors. We analysed the data using several specifications of a random parameter model to account for various sources of preference heterogeneity. By modelling preference heterogeneity, we showed how sensitivity to different incentives varied in different sections of the population. In particular, doctors from rural backgrounds were more sensitive than others to a 45% salary increase and having a post near their home province, but they were less sensitive to a reduction in the number of on-call nights. On the basis of the model results, the effects of two types of interventions were simulated: introducing various incentives and modifying the population structure. The results of the simulations provide multiple elements for consideration for policy-makers interested in designing effective interventions. They also underline the interest of modelling preference heterogeneity carefully. Copyright © 2013 John Wiley & Sons, Ltd.

OntoPop: An Ontology Population System for the Semantic Web

NASA Astrophysics Data System (ADS)

Thongkrau, Theerayut; Lalitrojwong, Pattarachai

The development of ontology at the instance level requires the extraction of the terms defining the instances from various data sources. These instances then are linked to the concepts of the ontology, and relationships are created between these instances for the next step. However, before establishing links among data, ontology engineers must classify terms or instances from a web document into an ontology concept. The tool for help ontology engineer in this task is called ontology population. The present research is not suitable for ontology development applications, such as long time processing or analyzing large or noisy data sets. OntoPop system introduces a methodology to solve these problems, which comprises two parts. First, we select meaningful features from syntactic relations, which can produce more significant features than any other method. Second, we differentiate feature meaning and reduce noise based on latent semantic analysis. Experimental evaluation demonstrates that the OntoPop works well, significantly out-performing the accuracy of 49.64%, a learning accuracy of 76.93%, and executes time of 5.46 second/instance.

Age and growth of flathead catfish, Pylodictus olivaris rafinesque, in the Altamaha River system, Georgia

USGS Publications Warehouse

Grabowski, T.B.; Isely, J.J.; Weller, R.R.

2004-01-01

Flathead catfish were introduced to the Altamaha River system, Georgia in the 1970's. We determined the length-weight relationship, Von Bertalanffy growth parameters, and back calculated lengths by examining the sagittal otoliths of 331 individuals captured from this population. We found that there were no sex related differences in length weight relationship or Von Bertalanffy growth parameters. Flathead catfish in the Altamaha River system grow at about the same rate as individuals in other introduced populations.

Differential Selection by Nematodes on an Introduced Biocontrol Fungus vs. Indigenous Fungi in Nonsterile Soil.

PubMed

Kim, Tae Gwan; Knudsen, Guy R

2018-03-15

Trophic interactions of introduced biocontrol fungi with soil animals can bea key determinant in the fungal proliferation and activity.This study investigated trophic interaction of an introduced biocontrol fungus with soil nematodes. The biocontrol fungus Trichoderma harzianum ThzID1-M3 and the fungivorous nematode Aphelenchoides sp. (10 per gram of soil) were added to nonsterile soil, and microbial populations were monitored for 40 days. Similar results were obtained when the experiment was duplicated. ThzID1-M3 stimulated the population growth of indigenous nematodes ( p <0.05), regardless of whether Aphelenchoides sp.was added.Without ThzID1-M3, indigenous nematodes did not increase in number and the added Aphelenchoides sp. nematodes almost disappeared by day 10. With ThzID1-M3, population growth of nematodes was rapid between 5 and 10 days after treatment. ThzID1-M3 biomass peaked on day 5, dropped at day 10, and then almost disappeared at day 20, which was not influenced by the addition of nematodes.In contrast, a large quantity of ThzID1-M3 hyphae were present in a heat-treated soil in which nematodes were eliminated.Total fungal biomass in all treatments peaked on day 5 and subsequently decreased.Addition of nematodes increased the total fungal biomass ( p <0.05), but ThzID1-M3 addition did not affect the fungal biomass.Hyphae oftotal fungi when homogenously distributed did not support the nematode population growth; however, hyphae of the introduced fungus when densely localized did.The results suggest that soil fungivorous nematodes are an important constraint onhyphal proliferation of fungal agents introduced into natural soils.

Integration versus apartheid in post-Roman Britain: a response to Thomas et Al. (2008).

PubMed

Pattison, John E

2011-12-01

The genetic surveys of the population of Britain conducted by Weale et al. and Capelli et al. produced estimates of the Germani immigration into Britain during the early Anglo-Saxon period, c.430-c.730. These estimates are considerably higher than the estimates of archaeologists. A possible explanation suggests that an apartheid-like social system existed in the early Anglo-Saxon kingdoms resulting in the Germani breeding more quickly than the Britons. Thomas et al. attempted to model this suggestion and showed that it was a possible explanation if all Anglo-Saxon kingdoms had such a system for up to 400 years. I noted that their explanation ignored the probability that Germani have been arriving in Britain for at least the past three millennia, including Belgae and Roman soldiers, and not only during the early Anglo-Saxon period. I produced a population model for Britain taking into account this long term, low level migration that showed that the estimates could be reconciled without the need for introducing an apartheid-like system. In turn, Thomas et al. responded, criticizing my model and arguments, which they considered persuasively written but wanting in terms of methodology, data sources, underlying assumptions, and application. Here, I respond in detail to those criticisms and argue that it is still unnecessary to introduce an apartheid-like system in order to reconcile the different estimates of Germani arrivals. A point of confusion is that geneticists are interested in ancestry, while archaeologists are interested in ethnicity: it is the bones, not the burial rites, which are important in the present context.

40 CFR 415.366 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Copper Salts... CFR 403.7, any new source subject to this subpart and producing copper sulfate, copper chloride, copper iodide, or copper nitrate which introduces pollutants into a publicly owned treatment works must...

40 CFR 415.366 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Copper Salts... CFR 403.7, any new source subject to this subpart and producing copper sulfate, copper chloride, copper iodide, or copper nitrate which introduces pollutants into a publicly owned treatment works must...

40 CFR 421.85 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Zinc... existing sources. The mass of wastewater pollutants in primary zinc process wastewater introduced into a POTW shall not exceed the following values: (a) Subpart H—Zinc Reduction Furnace Wet Air Pollution...

Density Dependent Functional Forms Drive Compensation in Populations Exposed to Stressors

EPA Science Inventory

The interaction between density dependence (DD) and environmental stressors can result in a compensatory or synergistic response in population growth, and population models that use density-independent demographic rates or generic DD functions may be introducing bias into managem...

Genetic consequences of trumpeter swan (Cygnus buccinator) reintroductions

USGS Publications Warehouse

Ransler, F.A.; Quinn, T.W.; Oyler-McCance, S.J.

2011-01-01

Relocation programs are often initiated to restore threatened species to previously occupied portions of their range. A primary challenge of restoration efforts is to translocate individuals in a way that prevents loss of genetic diversity and decreases differentiation relative to source populations-a challenge that becomes increasingly difficult when remnant populations of the species are already genetically depauperate. Trumpeter swans were previously extirpated in the entire eastern half of their range. Physical translocations of birds over the last 70 years have restored the species to portions of its historical range. Despite the long history of management, there has been little monitoring of the genetic outcomes of these restoration attempts. We assessed the consequences of this reintroduction program by comparing patterns of genetic variation at 17 microsatellite loci across four restoration flocks (three wild-released, one captive) and their source populations. We found that a wild-released population established from a single source displayed a trend toward reduced genetic diversity relative to and significant genetic differentiation from its source population, though small founder population effects may also explain this pattern. Wild-released flocks restored from multiple populations maintained source levels of genetic variation and lacked significant differentiation from at least one of their sources. Further, the flock originating from a single source revealed significantly lower levels of genetic variation than those established from multiple sources. The distribution of genetic variation in the captive flock was similar to its source. While the case of trumpeter swans provides evidence that restorations from multiple versus single source populations may better preserve natural levels of genetic diversity, more studies are needed to understand the general applicability of this management strategy. ?? 2010 Springer Science+Business Media B.V. (outside the USA).

Blind Channel Equalization with Colored Source Based on Constrained Optimization Methods

NASA Astrophysics Data System (ADS)

Wang, Yunhua; DeBrunner, Linda; DeBrunner, Victor; Zhou, Dayong

2008-12-01

Tsatsanis and Xu have applied the constrained minimum output variance (CMOV) principle to directly blind equalize a linear channel—a technique that has proven effective with white inputs. It is generally assumed in the literature that their CMOV method can also effectively equalize a linear channel with a colored source. In this paper, we prove that colored inputs will cause the equalizer to incorrectly converge due to inadequate constraints. We also introduce a new blind channel equalizer algorithm that is based on the CMOV principle, but with a different constraint that will correctly handle colored sources. Our proposed algorithm works for channels with either white or colored inputs and performs equivalently to the trained minimum mean-square error (MMSE) equalizer under high SNR. Thus, our proposed algorithm may be regarded as an extension of the CMOV algorithm proposed by Tsatsanis and Xu. We also introduce several methods to improve the performance of our introduced algorithm in the low SNR condition. Simulation results show the superior performance of our proposed methods.

Consequences of parental care on population dynamics

NASA Astrophysics Data System (ADS)

de Oliveira, S. Moss

1999-12-01

We review the results obtained using the Penna model for biological ageing (T.J.P. Penna, J. Stat. Phys. 78 (1995) 1629) when different strategies of parental care are introduced into evolving populations. These results concern to: longevity of semelparous populations; self-organization of female menopause; the spatial distribution of the populations and finally, sexual fidelity.

The role of Allee effects in gypsy moth, Lymantria dispar (L.), invasions

Treesearch

Patrick C. Tobin; Christelle Robinet; Derek M. Johnson; Stefanie L. Whitmire; Ottar N. Bjornstad; Andrew M. Liebhold

2009-01-01

Allee effects have been applied historically in efforts to understand the low-density population dynamics of rare and endangered species. Many biological invasions likewise experience the phenomenon of decreasing population growth rates at low population densities because most founding populations of introduced nonnative species occur at low densities. In range...

Using a virtual population to authentically teach epidemiology and biostatistics

NASA Astrophysics Data System (ADS)

Dunn, Peter K.; Donnison, Sharn; Cole, Rachel; Bulmer, Michael

2017-02-01

Epidemiology is the study of the distribution of disease in human populations. This means that authentically teaching primary data collection in epidemiology is difficult as students cannot easily access suitable human populations. Using an action research methodology, this paper studied the use of a virtual human population (called The Island) to enable students to experience many features of authentic primary data collection in epidemiological research. The Island was used in a course introducing epidemiology and biostatistics for students in non-quantitative disciplines. This paper discusses how The Island was introduced into the course, and then evaluates the change. Students were highly engaged, and students and teaching staff responded favourably to the use of The Island, with 70% of students agreeing or strongly agreeing that The Island was easy to use, and 64% agreeing or strongly agreeing that the use of a virtual population was beneficial to their understanding of epidemiology.

Ensuring successful introduction of Wolbachia in natural populations of Aedes aegypti by means of feedback control.

PubMed

Bliman, Pierre-Alexandre; Aronna, M Soledad; Coelho, Flávio C; da Silva, Moacyr A H B

2018-04-01

The control of the spread of dengue fever by introduction of the intracellular parasitic bacterium Wolbachia in populations of the vector Aedes aegypti, is presently one of the most promising tools for eliminating dengue, in the absence of an efficient vaccine. The success of this operation requires locally careful planning to determine the adequate number of individuals carrying the Wolbachia parasite that need to be introduced into the natural population. The introduced mosquitoes are expected to eventually replace the Wolbachia-free population and guarantee permanent protection against the transmission of dengue to human. In this study, we propose and analyze a model describing the fundamental aspects of the competition between mosquitoes carrying Wolbachia and mosquitoes free of the parasite. We then use feedback control techniques to devise an introduction protocol that is proved to guarantee that the population converges to a stable equilibrium where the totality of mosquitoes carry Wolbachia.

40 CFR 415.364 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2012 CFR

2012-07-01

... sulfate, copper chloride, copper iodide, or copper nitrate which introduces pollutants into a publicly... for existing sources (PSES): Subpart AJ—Copper Sulfate, Copper Chloride, Copper Iodide, Copper Nitrate...

40 CFR 415.364 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2011 CFR

2011-07-01

... sulfate, copper chloride, copper iodide, or copper nitrate which introduces pollutants into a publicly... for existing sources (PSES): Subpart AJ—Copper Sulfate, Copper Chloride, Copper Iodide, Copper Nitrate...

40 CFR 415.364 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2014 CFR

2014-07-01

... sulfate, copper chloride, copper iodide, or copper nitrate which introduces pollutants into a publicly... for existing sources (PSES): Subpart AJ—Copper Sulfate, Copper Chloride, Copper Iodide, Copper Nitrate...

40 CFR 415.364 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2010 CFR

2010-07-01

... sulfate, copper chloride, copper iodide, or copper nitrate which introduces pollutants into a publicly... for existing sources (PSES): Subpart AJ—Copper Sulfate, Copper Chloride, Copper Iodide, Copper Nitrate...

LIGO and the opening of a unique observational window on the universe.

PubMed

Kalogera, Vassiliki; Lazzarini, Albert

2017-03-21

A unique window on the universe opened on September 14, 2015, with direct detection of gravitational waves by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors. This event culminated a half-century effort around the globe to develop terrestrial detectors of adequate sensitivity to achieve this goal. It also happened appropriately only a few months before the centennial of Einstein's final paper introducing the general theory of relativity. This detection provided the surprising discovery of a coalescing pair of "heavy" black holes (more massive than [Formula: see text] M[Formula: see text]) leading to the formation of a spinning [Formula: see text]62 solar mass black hole. One more binary black-hole detection and a significant candidate event demonstrated that a population of such merging binaries is formed in nature with a broad mass spectrum. This unique observational sample has already provided concrete measurements on the coalescence rates and has allowed us to test the theory of general relativity in the strong-field regime. As this nascent field of gravitational-wave astrophysics is emerging we are looking forward to the detection of binary mergers involving neutron stars and their electromagnetic counterparts, as well as continuous-wave sources, supernovae, a stochastic confusion background of compact-object mergers, known sources detected in unexpected ways, and completely unknown sources.

LIGO and the opening of a unique observational window on the universe

PubMed Central

Kalogera, Vassiliki; Lazzarini, Albert

2017-01-01

A unique window on the universe opened on September 14, 2015, with direct detection of gravitational waves by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors. This event culminated a half-century effort around the globe to develop terrestrial detectors of adequate sensitivity to achieve this goal. It also happened appropriately only a few months before the centennial of Einstein’s final paper introducing the general theory of relativity. This detection provided the surprising discovery of a coalescing pair of “heavy” black holes (more massive than ≃25 M๏) leading to the formation of a spinning ≃62 solar mass black hole. One more binary black-hole detection and a significant candidate event demonstrated that a population of such merging binaries is formed in nature with a broad mass spectrum. This unique observational sample has already provided concrete measurements on the coalescence rates and has allowed us to test the theory of general relativity in the strong-field regime. As this nascent field of gravitational-wave astrophysics is emerging we are looking forward to the detection of binary mergers involving neutron stars and their electromagnetic counterparts, as well as continuous-wave sources, supernovae, a stochastic confusion background of compact-object mergers, known sources detected in unexpected ways, and completely unknown sources. PMID:28283663

Benzophenone-type UV filters in surface waters: An assessment of profiles and ecological risks in Shanghai, China.

PubMed

Wu, Ming-Hong; Xie, Deng-Guo; Xu, Gang; Sun, Rui; Xia, Xiao-Yu; Liu, Wen-Long; Tang, Liang

2017-07-01

Benzophenone-type UV filters (BP-UV filters) are frequently introduced into aquatic environment from several sources. The occurrence and fate of select BP-UV filters and their metabolites were investigated in this study. All target compounds were detected in water samples, except for 2, 3, 4-trihydroxybenzophenone (2, 3, 4-OH-BP). The concentration reached up 131ngL -1 for 5-benzoyl-4-hydroxy-2-ethoxybenzenesulfonic acid (BP-4), 30.0ngL -1 for 2-hydroxy-4-methoxybenzophenone (BP-3), and mean value of 158ngL -1 for benzophenone (BP). Concentrations of BP-UV filters were not related to recreational waters but with high population frequencies. In addition, five BP-UV filters, namely 2,2',4,4'-tetrahydroxybenzophenone (BP-2), 2,3,4-OH-BP, 2,4-dihydroxybenzophenone (BP-1), 4-hydroxybenzophenone (4-OH-BP) and BP were investigated for probable sources, and found that they originate from BP-3 metabolism. There is a similar source for BP-3, BP-4, BP-1, 4-OH-BP and BP. Environmental risk assessment (ERA) showed that risk quotients (RQs) of BP-4, BP-3 and BP were 2.7, 0.8 and 0.5, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

Shear nulling after PSF Gaussianisation: Moment-based weak lensing measurements with subpercent noise bias

NASA Astrophysics Data System (ADS)

Herbonnet, Ricardo; Buddendiek, Axel; Kuijken, Konrad

2017-03-01

Context. Current optical imaging surveys for cosmology cover large areas of sky. Exploiting the statistical power of these surveys for weak lensing measurements requires shape measurement methods with subpercent systematic errors. Aims: We introduce a new weak lensing shear measurement algorithm, shear nulling after PSF Gaussianisation (SNAPG), designed to avoid the noise biases that affect most other methods. Methods: SNAPG operates on images that have been convolved with a kernel that renders the point spread function (PSF) a circular Gaussian, and uses weighted second moments of the sources. The response of such second moments to a shear of the pre-seeing galaxy image can be predicted analytically, allowing us to construct a shear nulling scheme that finds the shear parameters for which the observed galaxies are consistent with an unsheared, isotropically oriented population of sources. The inverse of this nulling shear is then an estimate of the gravitational lensing shear. Results: We identify the uncertainty of the estimated centre of each galaxy as the source of noise bias, and incorporate an approximate estimate of the centroid covariance into the scheme. We test the method on extensive suites of simulated galaxies of increasing complexity, and find that it is capable of shear measurements with multiplicative bias below 0.5 percent.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goltz, M.N.; Kawakami, B.T.; McCarty, P.L.

A full-scale study of in-situ bioremediation is being planned for implementation at Edwards Air Force Base. The bioremediation system that is being proposed has been developed over 8 years of research and testing in the laboratory and at a pilot field site located at Moffett Naval Air Station in Mountain View, California. Studies conducted at the Moffett field site have demonstrated that trichloroethylene (TCE), the contaminant found at Edwards, can be effectively biodegraded cometabolically through the introduction into the subsurface of a primary substrate and an oxygen source to support the growth and energy requirements of a native population ofmore » microorganisms. One of the main questions that needs to be answered, prior to full-scale demonstration of this technology on the Edwards TCE plume, is how best to mix a primary substrate, an oxygen source, and TCE, and subsequently get the mixture to the microorganisms. At Moffett Field, mixing of these three components was accomplished above ground, with the mixture then introduced into the subsurface through an injection well. In the full-scale demonstration, the TCE will, of course, already be in the groundwater. A major objective of the demonstration will be to investigate how a primary substrate and an oxygen source can be efficiently mixed and transported to indigenous microorganisms, in order to promote cometabolic degradation of TCE.« less

Identification of Neosho Smallmouth Bass (Micropterus dolomieu velox) stocks for possible introduction into Grand Lake, Oklahoma

USGS Publications Warehouse

Taylor, Andrew T.; Long, James M.; Schwemm, Michael R.; Tringali, Michael D.; Brewer, Shannon K.

2016-01-01

Stocking black basses (Micropterus spp.) is a common practice used to increase angling opportunities in impoundments; however, when non-native black basses are introduced they often invade riverine habitats where they threaten the persistence of other fishes, including native black basses. Neosho Smallmouth Bass (M. dolomieu velox) is endemic to portions of the Ozark Highlands and Boston Mountains ecoregions and is threatened by introductions of non-native Smallmouth Bass (“SMB”) forms. Because of recent interest in stocking SMB into Grand Lake o’ the Cherokees, we assessed the suitability of local Neosho SMB populations as potential broodstock sources by assessing introgression with non-native SMB forms, as well as characterizing population structure and genetic diversity. The majority of Neosho SMB populations contained low, but non-negligible, genomic proportions of two genetically distinct non-native SMB forms. Introgression was highest in the Illinois River upstream of Lake Tenkiller, where Tennessee ‘lake strain’ SMB were stocked in the early 1990’s. We recovered three genetically distinct clusters of Neosho SMB at the uppermost hierarchical level of population structure: a distinct Illinois River cluster and two Grand River clusters that appear to naturally mix at some sites. Genetic diversity measures generally increased with stream size, and smaller populations with low diversity measures may benefit from immigration of novel genetic material. Overall, introgression with non-native SMB forms appears to pose a prominent threat to Neosho SMB; however, relatively intact populations of Neosho SMB exist in some Grand Lake o’ the Cherokees tributaries. Results could be used in developing a stocking program that promotes and sustains existing genetic diversity within and among Neosho SMB populations.

A Semantic Transformation Methodology for the Secondary Use of Observational Healthcare Data in Postmarketing Safety Studies.

PubMed

Pacaci, Anil; Gonul, Suat; Sinaci, A Anil; Yuksel, Mustafa; Laleci Erturkmen, Gokce B

2018-01-01

Background: Utilization of the available observational healthcare datasets is key to complement and strengthen the postmarketing safety studies. Use of common data models (CDM) is the predominant approach in order to enable large scale systematic analyses on disparate data models and vocabularies. Current CDM transformation practices depend on proprietarily developed Extract-Transform-Load (ETL) procedures, which require knowledge both on the semantics and technical characteristics of the source datasets and target CDM. Purpose: In this study, our aim is to develop a modular but coordinated transformation approach in order to separate semantic and technical steps of transformation processes, which do not have a strict separation in traditional ETL approaches. Such an approach would discretize the operations to extract data from source electronic health record systems, alignment of the source, and target models on the semantic level and the operations to populate target common data repositories. Approach: In order to separate the activities that are required to transform heterogeneous data sources to a target CDM, we introduce a semantic transformation approach composed of three steps: (1) transformation of source datasets to Resource Description Framework (RDF) format, (2) application of semantic conversion rules to get the data as instances of ontological model of the target CDM, and (3) population of repositories, which comply with the specifications of the CDM, by processing the RDF instances from step 2. The proposed approach has been implemented on real healthcare settings where Observational Medical Outcomes Partnership (OMOP) CDM has been chosen as the common data model and a comprehensive comparative analysis between the native and transformed data has been conducted. Results: Health records of ~1 million patients have been successfully transformed to an OMOP CDM based database from the source database. Descriptive statistics obtained from the source and target databases present analogous and consistent results. Discussion and Conclusion: Our method goes beyond the traditional ETL approaches by being more declarative and rigorous. Declarative because the use of RDF based mapping rules makes each mapping more transparent and understandable to humans while retaining logic-based computability. Rigorous because the mappings would be based on computer readable semantics which are amenable to validation through logic-based inference methods.

psiTurk: An open-source framework for conducting replicable behavioral experiments online.

PubMed

Gureckis, Todd M; Martin, Jay; McDonnell, John; Rich, Alexander S; Markant, Doug; Coenen, Anna; Halpern, David; Hamrick, Jessica B; Chan, Patricia

2016-09-01

Online data collection has begun to revolutionize the behavioral sciences. However, conducting carefully controlled behavioral experiments online introduces a number of new of technical and scientific challenges. The project described in this paper, psiTurk, is an open-source platform which helps researchers develop experiment designs which can be conducted over the Internet. The tool primarily interfaces with Amazon's Mechanical Turk, a popular crowd-sourcing labor market. This paper describes the basic architecture of the system and introduces new users to the overall goals. psiTurk aims to reduce the technical hurdles for researchers developing online experiments while improving the transparency and collaborative nature of the behavioral sciences.

Health Surveys Using Mobile Phones in Developing Countries: Automated Active Strata Monitoring and Other Statistical Considerations for Improving Precision and Reducing Biases.

PubMed

Labrique, Alain; Blynn, Emily; Ahmed, Saifuddin; Gibson, Dustin; Pariyo, George; Hyder, Adnan A

2017-05-05

In low- and middle-income countries (LMICs), historically, household surveys have been carried out by face-to-face interviews to collect survey data related to risk factors for noncommunicable diseases. The proliferation of mobile phone ownership and the access it provides in these countries offers a new opportunity to remotely conduct surveys with increased efficiency and reduced cost. However, the near-ubiquitous ownership of phones, high population mobility, and low cost require a re-examination of statistical recommendations for mobile phone surveys (MPS), especially when surveys are automated. As with landline surveys, random digit dialing remains the most appropriate approach to develop an ideal survey-sampling frame. Once the survey is complete, poststratification weights are generally applied to reduce estimate bias and to adjust for selectivity due to mobile ownership. Since weights increase design effects and reduce sampling efficiency, we introduce the concept of automated active strata monitoring to improve representativeness of the sample distribution to that of the source population. Although some statistical challenges remain, MPS represent a promising emerging means for population-level data collection in LMICs. ©Alain Labrique, Emily Blynn, Saifuddin Ahmed, Dustin Gibson, George Pariyo, Adnan A Hyder. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 05.05.2017.

An ecological risk assessment of nonnative boas and pythons as potentially invasive species in the United States.

PubMed

Reed, Robert N

2005-06-01

The growing international trade in live wildlife has the potential to result in continuing establishment of nonnative animal populations in the United States. Snakes may pose particularly high risks as potentially invasive species, as exemplified by the decimation of Guam's vertebrate fauna by the accidentally introduced brown tree snake. Herein, ecological and commercial predictors of the likelihood of establishment of invasive populations were used to model risk associated with legal commercial imports of 23 species of boas, pythons, and relatives into the United States during the period 1989-2000. Data on ecological variables were collected from multiple sources, while data on commercial variables were collated from import records maintained by the U.S. Fish and Wildlife Service. Results of the risk-assessment models indicate that species including boa constrictors (Boa constrictor), ball pythons (Python regius), and reticulated pythons (P. reticulatus) may pose particularly high risks as potentially invasive species. Recommendations for reducing risk of establishment of invasive populations of snakes and/or pathogens include temporary quarantine of imports to increase detection rates of nonnative pathogens, increasing research attention to reptile pathogens, reducing the risk that nonnative snakes will reach certain areas with high numbers of federally listed species (such as the Florida Keys), and attempting to better educate individuals purchasing reptiles.

Ion Composition and Energization in the Earth's Inner Magnetosphere and the Effects on Ring Current Buildup

NASA Astrophysics Data System (ADS)

Keika, K.; Kistler, L. M.; Brandt, P. C.

2014-12-01

In-situ observations and modeling work have confirmed that singly-charged oxygen ions, O+, which are of Earth's ionospheric origin, are heated/accelerated up to >100 keV in the magnetosphere. The energetic O+ population makes a significant contribution to the plasma pressure in the Earth's inner magnetosphere during magnetic storms, although under quiet conditions H+ dominates the plasma pressure. The pressure enhancements, which we term energization, are caused by adiabatic heating through earthward transport of source population in the plasma sheet, local acceleration in the inner magnetosphere and near-Earth plasma sheet, and enhanced ion supply from the topside ionosphere. The key issues regarding stronger O+ energization than H+ are non-adiabatic local acceleration, responsible for increase in O+ temperature, and more significant O+ supply than H+, responsible for increase in O+ density. Although several acceleration mechanisms and O+ supply processes have been proposed, it remains an open question what mechanism(s)/process(es) play the dominant role in stronger O+ energization. In this paper we summarize important spacecraft observations including those from Van Allen Probes, introduces the proposed mechanisms/processes that generate O+-rich energetic plasma population, and outlines possible scenarios of O+ pressure abundance in the Earth's inner magnetosphere.

Generalized fish life-cycle poplulation model and computer program

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeAngelis, D. L.; Van Winkle, W.; Christensen, S. W.

1978-03-01

A generalized fish life-cycle population model and computer program have been prepared to evaluate the long-term effect of changes in mortality in age class 0. The general question concerns what happens to a fishery when density-independent sources of mortality are introduced that act on age class 0, particularly entrainment and impingement at power plants. This paper discusses the model formulation and computer program, including sample results. The population model consists of a system of difference equations involving age-dependent fecundity and survival. The fecundity for each age class is assumed to be a function of both the fraction of females sexuallymore » mature and the weight of females as they enter each age class. Natural mortality for age classes 1 and older is assumed to be independent of population size. Fishing mortality is assumed to vary with the number and weight of fish available to the fishery. Age class 0 is divided into six life stages. The probability of survival for age class 0 is estimated considering both density-independent mortality (natural and power plant) and density-dependent mortality for each life stage. Two types of density-dependent mortality are included. These are cannibalism of each life stage by older age classes and intra-life-stage competition.« less

40 CFR 421.295 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin... existing sources. The mass of wastewater pollutants in secondary tin process wastewater introduced into a POTW must not exceed the following values: (a) Tin smelter SO2 scrubber. PSES for the Secondary Tin...

40 CFR 421.295 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin... existing sources. The mass of wastewater pollutants in secondary tin process wastewater introduced into a POTW must not exceed the following values: (a) Tin smelter SO2 scrubber. PSES for the Secondary Tin...

40 CFR 421.295 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin... existing sources. The mass of wastewater pollutants in secondary tin process wastewater introduced into a POTW must not exceed the following values: (a) Tin smelter SO2 scrubber. PSES for the Secondary Tin...

40 CFR 421.295 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin... existing sources. The mass of wastewater pollutants in secondary tin process wastewater introduced into a POTW must not exceed the following values: (a) Tin smelter SO2 scrubber. PSES for the Secondary Tin...

40 CFR 421.295 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin... existing sources. The mass of wastewater pollutants in secondary tin process wastewater introduced into a POTW must not exceed the following values: (a) Tin smelter SO2 scrubber. PSES for the Secondary Tin...

A Conceptual Framework for Primary Source Practices

ERIC Educational Resources Information Center

Ensminger, David C.; Fry, Michelle L.

2012-01-01

This article introduces a descriptive conceptual framework to provide teachers with a means of recognizing and describing instructional activities that use primary sources. The framework provides structure for professional development programs that have been established to train teachers to access and integrate primary sources into lessons. The…

Phenotypic and genomic analysis of a fast neutron mutant population resource in soybean

USDA-ARS?s Scientific Manuscript database

Mutagenized populations have become indispensable resources for introducing variation and studying gene function in plant genomics research. We utilized fast neutron radiation to induce deletion mutations in the soybean genome and phenotypically screened the resulting population. We exposed approxim...

Virtual increase or latent loss? A reassessment of mangrove populations and their conservation in Guangdong, southern China.

PubMed

Peng, Yisheng; Zheng, Mingxuan; Zheng, Zhouxiang; Wu, Guichang; Chen, Yuechao; Xu, Hualin; Tian, Guanghong; Peng, Shenghua; Chen, Guizhu; Lee, Shing Yip

2016-08-30

Contrary to the global trend, the area of mangrove in Guangdong Province, southern China, has been increasing over the last two decades. Currently, three exotic mangrove species have been introduced for large-scale afforestation since 1985. A reassessment of the overall status of the mangrove species, habitat change, population of introduced species, was conducted through a comprehensive literature review as well as field investigations covering 96 sites. The success of conservation efforts is also evaluated. Upstream and high intertidal habitats are more vulnerable than downstream and lower intertidal ones, with habitat alteration being the biggest threats. Five mangrove species have narrow distributional extents with small populations, which could incur regional extinction. With the introduced species having naturalized at 42 sites, their role in mangrove management needs to be reconsidered. These findings collectively suggest a need to manage latent species loss and habitat degradation beyond the apparent increase in mangrove area and protection. Copyright © 2016 Elsevier Ltd. All rights reserved.

Constructing stage-structured matrix population models from life tables: comparison of methods

PubMed Central

Diaz-Lopez, Jasmin

2017-01-01

A matrix population model is a convenient tool for summarizing per capita survival and reproduction rates (collectively vital rates) of a population and can be used for calculating an asymptotic finite population growth rate (λ) and generation time. These two pieces of information can be used for determining the status of a threatened species. The use of stage-structured population models has increased in recent years, and the vital rates in such models are often estimated using a life table analysis. However, potential bias introduced when converting age-structured vital rates estimated from a life table into parameters for a stage-structured population model has not been assessed comprehensively. The objective of this study was to investigate the performance of methods for such conversions using simulated life histories of organisms. The underlying models incorporate various types of life history and true population growth rates of varying levels. The performance was measured by comparing differences in λ and the generation time calculated using the Euler-Lotka equation, age-structured population matrices, and several stage-structured population matrices that were obtained by applying different conversion methods. The results show that the discretization of age introduces only small bias in λ or generation time. Similarly, assuming a fixed age of maturation at the mean age of maturation does not introduce much bias. However, aggregating age-specific survival rates into a stage-specific survival rate and estimating a stage-transition rate can introduce substantial bias depending on the organism’s life history type and the true values of λ. In order to aggregate survival rates, the use of the weighted arithmetic mean was the most robust method for estimating λ. Here, the weights are given by survivorship curve after discounting with λ. To estimate a stage-transition rate, matching the proportion of individuals transitioning, with λ used for discounting the rate, was the best approach. However, stage-structured models performed poorly in estimating generation time, regardless of the methods used for constructing the models. Based on the results, we recommend using an age-structured matrix population model or the Euler-Lotka equation for calculating λ and generation time when life table data are available. Then, these age-structured vital rates can be converted into a stage-structured model for further analyses. PMID:29085763

Constructing stage-structured matrix population models from life tables: comparison of methods.

PubMed

Fujiwara, Masami; Diaz-Lopez, Jasmin

2017-01-01

A matrix population model is a convenient tool for summarizing per capita survival and reproduction rates (collectively vital rates) of a population and can be used for calculating an asymptotic finite population growth rate ( λ ) and generation time. These two pieces of information can be used for determining the status of a threatened species. The use of stage-structured population models has increased in recent years, and the vital rates in such models are often estimated using a life table analysis. However, potential bias introduced when converting age-structured vital rates estimated from a life table into parameters for a stage-structured population model has not been assessed comprehensively. The objective of this study was to investigate the performance of methods for such conversions using simulated life histories of organisms. The underlying models incorporate various types of life history and true population growth rates of varying levels. The performance was measured by comparing differences in λ and the generation time calculated using the Euler-Lotka equation, age-structured population matrices, and several stage-structured population matrices that were obtained by applying different conversion methods. The results show that the discretization of age introduces only small bias in λ or generation time. Similarly, assuming a fixed age of maturation at the mean age of maturation does not introduce much bias. However, aggregating age-specific survival rates into a stage-specific survival rate and estimating a stage-transition rate can introduce substantial bias depending on the organism's life history type and the true values of λ . In order to aggregate survival rates, the use of the weighted arithmetic mean was the most robust method for estimating λ . Here, the weights are given by survivorship curve after discounting with λ . To estimate a stage-transition rate, matching the proportion of individuals transitioning, with λ used for discounting the rate, was the best approach. However, stage-structured models performed poorly in estimating generation time, regardless of the methods used for constructing the models. Based on the results, we recommend using an age-structured matrix population model or the Euler-Lotka equation for calculating λ and generation time when life table data are available. Then, these age-structured vital rates can be converted into a stage-structured model for further analyses.

40 CFR 419.15 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2010 CFR

2010-07-01

... source subject to this subpart which introduces pollutants into a publicly owned treatment works must...). The following standards apply to the total refinery flow contribution to the POTW: Pollutant or...

40 CFR 419.45 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2010 CFR

2010-07-01

... source subject to this subpart which introduces pollutants into a publicly owned treatment works must...). The following standards apply to the total refinery flow contribution to the POTW: Pollutant or...

40 CFR 419.55 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2010 CFR

2010-07-01

... source subject to this subpart which introduces pollutants into a publicly owned treatment works must... following standards apply to the total refinery flow contribution to the POTW: Pollutant or pollutant...

Trends and Variability of Global Fire Emissions Due To Historical Anthropogenic Activities

NASA Astrophysics Data System (ADS)

Ward, Daniel S.; Shevliakova, Elena; Malyshev, Sergey; Rabin, Sam

2018-01-01

Globally, fires are a major source of carbon from the terrestrial biosphere to the atmosphere, occurring on a seasonal cycle and with substantial interannual variability. To understand past trends and variability in sources and sinks of terrestrial carbon, we need quantitative estimates of global fire distributions. Here we introduce an updated version of the Fire Including Natural and Agricultural Lands model, version 2 (FINAL.2), modified to include multiday burning and enhanced fire spread rate in forest crowns. We demonstrate that the improved model reproduces the interannual variability and spatial distribution of fire emissions reported in present-day remotely sensed inventories. We use FINAL.2 to simulate historical (post-1700) fires and attribute past fire trends and variability to individual drivers: land use and land cover change, population growth, and lightning variability. Global fire emissions of carbon increase by about 10% between 1700 and 1900, reaching a maximum of 3.4 Pg C yr-1 in the 1910s, followed by a decrease to about 5% below year 1700 levels by 2010. The decrease in emissions from the 1910s to the present day is driven mainly by land use change, with a smaller contribution from increased fire suppression due to increased human population and is largest in Sub-Saharan Africa and South Asia. Interannual variability of global fire emissions is similar in the present day as in the early historical period, but present-day wildfires would be more variable in the absence of land use change.

Gossip-based solutions for discrete rendezvous in populations of communicating agents.

PubMed

Hollander, Christopher D; Wu, Annie S

2014-01-01

The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal) meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm.

Transverse bacterial migration induced by chemotaxis in a packed column with structured physical heterogeneity.

PubMed

Wang, Meng; Ford, Roseanne M

2009-08-01

The significance of chemotaxis in directing bacterial migration toward contaminants in natural porous media was investigated under groundwater flow conditions. A laboratory-scale column, with a coarse-grained sand core surrounded by a fine-grained annulus, was used to simulate natural aquifers with strata of different hydraulic conductivities. A chemoattractant source was placed along the central axis of the column to model contaminants trapped in the heterogeneous subsurface. Chemotactic bacterial strains, Escherichia coli HCB1 and Pseudomonas putida F1, introduced into the column by a pulse injection, were found to alter their transport behaviors under the influence of the attractant chemical emanating from the central source. For E. coil HCB1, approximately 18% more of the total population relative to the control without attractant exited the column from the coarse sand layer due to the chemotactic effects of alpha-methylaspartate under an average fluid velocity of 5.1 m/d. Although P. putida F1 demonstrated no observable changes in migration pathways with the model contaminant acetate under the same flow rate, when the flow rate was reduced to 1.9 m/d, approximately 6-10% of the population relative to the control migrated from the fine sand layer toward attractant into the coarse sand layer. Microbial transport properties were further quantified by a mathematical model to examine the significance of bacterial motility and chemotaxis under different hydrodynamic conditions, which suggested important considerations for strain selection and practical operation of bioremediation schemes.

Changes in leptospirosis etiology in animals and humans.

PubMed

Vasylieva, Natalia; Andreychyn, Mykhaylo; Kravchuk, Yulia; Chervinska, Оlena; Iosyk, Iaryna

2017-12-23

Leptospirosis is endemic in Ternopil region. In Ukraine, the disease is registered in almost all regions, including the Ternopil region. The aim of the research is to study the regularities of epidemic and epizootic processes of leptospirosis, and the circulation of its pathogens among different sources (small mammals, animals) and humans. Etiologic spectrum of leptospirosis registered in Ternopil region in 1972-2016 among small mammals, farm animals and sick people was studied. Due to the analysis of pathogens circulation among different sources (small mammals, animals), as well as the annual morbidity in humans, it was proved that new leptospira serovars are endemic and brought into the regions mostly by farm animals. Farm animals introduce the infection to humans through the environment, sometimes within 3-5-years. The spread was observed of pathogen serovars, which are new in certain areas, among all types of mouse-like small mammals and rats. It was established that livestock and small mammals are parallel reservoirs. In the regions with endemic species, the structural modification in the etiology of leptospirosis in humans is caused by additional reservoirs among animals, as well as the circulation of other pathogen serovars that were absent in the main natural reservoir, i.e. mouse-like small mammals and rats. The constant monitoring of the population, contamination and carrier state of mouse-like small mammals, rats and farm animals, is required In order to predict the future epidemiological situation on leptospirosis among the population and to improve leptospirosis diagnosis.

Gossip-Based Solutions for Discrete Rendezvous in Populations of Communicating Agents

PubMed Central

Hollander, Christopher D.; Wu, Annie S.

2014-01-01

The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal) meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm. PMID:25397882

Small founding number and low genetic diversity in an introduced species exhibiting limited invasion success (speckled dace, Rhinichthys ocsulus)

Treesearch

Andrew Kinziger; Rodney Nakamoto; Eric Anderson; Bret Harvey

2011-01-01

Molecular evaluations of successful invaders are common, however studies of introduced species that have had limited invasion success, or have died out completely, are rare. We studied an introduced population of speckled dace (Rhinichthys osculus) from northern California, USA that has rapidly increased in abundance but remained restricted to a 25-km stretch of river...

Reduced genetic variation and the success of an invasive species.

PubMed

Tsutsui, N D; Suarez, A V; Holway, D A; Case, T J

2000-05-23

Despite the severe ecological and economic damage caused by introduced species, factors that allow invaders to become successful often remain elusive. Of invasive taxa, ants are among the most widespread and harmful. Highly invasive ants are often unicolonial, forming supercolonies in which workers and queens mix freely among physically separate nests. By reducing costs associated with territoriality, unicolonial species can attain high worker densities, allowing them to achieve interspecific dominance. Here we examine the behavior and population genetics of the invasive Argentine ant (Linepithema humile) in its native and introduced ranges, and we provide a mechanism to explain its success as an invader. Using microsatellite markers, we show that a population bottleneck has reduced the genetic diversity of introduced populations. This loss is associated with reduced intraspecific aggression among spatially separate nests, and leads to the formation of interspecifically dominant supercolonies. In contrast, native populations are more genetically variable and exhibit pronounced intraspecific aggression. Although reductions in genetic diversity are generally considered detrimental, these findings provide an example of how a genetic bottleneck can lead to widespread ecological success. In addition, these results provide insights into the origin and evolution of unicoloniality, which is often considered a challenge to kin selection theory.

Spinosad and the Tomato Borer Tuta absoluta: A Bioinsecticide, an Invasive Pest Threat, and High Insecticide Resistance

PubMed Central

Campos, Mateus R.; Rodrigues, Agna Rita S.; Silva, Wellington M.; Silva, Tadeu Barbosa M.; Silva, Vitória Regina F.; Guedes, Raul Narciso C.; Siqueira, Herbert Alvaro A.

2014-01-01

The introduction of an agricultural pest species into a new environment is a potential threat to agroecosystems of the invaded area. The phytosanitary concern is even greater if the introduced pest’s phenotype expresses traits that will impair the management of that species. The invasive tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is one such species and the characterization of the insecticide resistance prevailing in the area of origin is important to guide management efforts in new areas of introduction. The spinosad is one the main insecticides currently used in Brazil for control of the tomato borer; Brazil is the likely source of the introduction of the tomato borer into Europe. For this reason, spinosad resistance in Brazilian populations of this species was characterized. Spinosad resistance has been reported in Brazilian field populations of this pest species, and one resistant population that was used in this study was subjected to an additional seven generations of selection for spinosad resistance reaching levels over 180,000-fold. Inheritance studies indicated that spinosad resistance is monogenic, incompletely recessive and autosomal with high heritability (h 2 = 0.71). Spinosad resistance was unstable without selection pressure with a negative rate of change in the resistance level ( = −0.51) indicating an associated adaptive cost. Esterases and cytochrome P450-dependent monooxygenases titration decreased with spinosad selection, indicating that these detoxification enzymes are not the underlying resistance mechanism. Furthermore, the cross-resistance spectrum was restricted to the insecticide spinetoram, another spinosyn, suggesting that altered target site may be the mechanism involved. Therefore, the suspension of spinosyn use against the tomato borer would be a useful component in spinosad resistance management for this species. Spinosad use against this species in introduced areas should be carefully monitored to prevent rapid selection of high levels of resistance and the potential for its spread to new areas. PMID:25122089

Spinosad and the tomato borer Tuta absoluta: a bioinsecticide, an invasive pest threat, and high insecticide resistance.

PubMed

Campos, Mateus R; Rodrigues, Agna Rita S; Silva, Wellington M; Silva, Tadeu Barbosa M; Silva, Vitória Regina F; Guedes, Raul Narciso C; Siqueira, Herbert Alvaro A

2014-01-01

The introduction of an agricultural pest species into a new environment is a potential threat to agroecosystems of the invaded area. The phytosanitary concern is even greater if the introduced pest's phenotype expresses traits that will impair the management of that species. The invasive tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is one such species and the characterization of the insecticide resistance prevailing in the area of origin is important to guide management efforts in new areas of introduction. The spinosad is one the main insecticides currently used in Brazil for control of the tomato borer; Brazil is the likely source of the introduction of the tomato borer into Europe. For this reason, spinosad resistance in Brazilian populations of this species was characterized. Spinosad resistance has been reported in Brazilian field populations of this pest species, and one resistant population that was used in this study was subjected to an additional seven generations of selection for spinosad resistance reaching levels over 180,000-fold. Inheritance studies indicated that spinosad resistance is monogenic, incompletely recessive and autosomal with high heritability (h(2) = 0.71). Spinosad resistance was unstable without selection pressure with a negative rate of change in the resistance level ( = -0.51) indicating an associated adaptive cost. Esterases and cytochrome P450-dependent monooxygenases titration decreased with spinosad selection, indicating that these detoxification enzymes are not the underlying resistance mechanism. Furthermore, the cross-resistance spectrum was restricted to the insecticide spinetoram, another spinosyn, suggesting that altered target site may be the mechanism involved. Therefore, the suspension of spinosyn use against the tomato borer would be a useful component in spinosad resistance management for this species. Spinosad use against this species in introduced areas should be carefully monitored to prevent rapid selection of high levels of resistance and the potential for its spread to new areas.

Host population persistence in the face of introduced vector-borne diseases: Hawaii amakihi and avian malaria

PubMed Central

Woodworth, Bethany L.; Atkinson, Carter T.; LaPointe, Dennis A.; Hart, Patrick J.; Spiegel, Caleb S.; Tweed, Erik J.; Henneman, Carlene; LeBrun, Jaymi; Denette, Tami; DeMots, Rachel; Kozar, Kelly L.; Triglia, Dennis; Lease, Dan; Gregor, Aaron; Smith, Tom; Duffy, David

2005-01-01

The past quarter century has seen an unprecedented increase in the number of new and emerging infectious diseases throughout the world, with serious implications for human and wildlife populations. We examined host persistence in the face of introduced vector-borne diseases in Hawaii, where introduced avian malaria and introduced vectors have had a negative impact on most populations of Hawaiian forest birds for nearly a century. We studied birds, parasites, and vectors in nine study areas from 0 to 1,800 m on Mauna Loa Volcano, Hawaii from January to October, 2002. Contrary to predictions of prior work, we found that Hawaii amakihi (Hemignathus virens), a native species susceptible to malaria, comprised from 24.5% to 51.9% of the avian community at three low-elevation forests (55–270 m). Amakihi were more abundant at low elevations than at disease-free high elevations, and were resident and breeding there. Infection rates were 24–40% by microscopy and 55–83% by serology, with most infected individuals experiencing low-intensity, chronic infections. Mosquito trapping and diagnostics provided strong evidence for year-round local transmission. Moreover, we present evidence that Hawaii amakihi have increased in low elevation habitats on southeastern Hawaii Island over the past decade. The recent emergent phenomenon of recovering amakihi populations at low elevations, despite extremely high prevalence of avian malaria, suggests that ecological or evolutionary processes acting on hosts or parasites have allowed this species to recolonize low-elevation habitats. A better understanding of the mechanisms allowing coexistence of hosts and parasites may ultimately lead to tools for mitigating disease impacts on wildlife and human populations. PMID:15668377

Host population persistence in the face of introduced vector-borne diseases: Hawaii amakihi and avian malaria.

PubMed

Woodworth, Bethany L; Atkinson, Carter T; Lapointe, Dennis A; Hart, Patrick J; Spiegel, Caleb S; Tweed, Erik J; Henneman, Carlene; Lebrun, Jaymi; Denette, Tami; Demots, Rachel; Kozar, Kelly L; Triglia, Dennis; Lease, Dan; Gregor, Aaron; Smith, Tom; Duffy, David

2005-02-01

The past quarter century has seen an unprecedented increase in the number of new and emerging infectious diseases throughout the world, with serious implications for human and wildlife populations. We examined host persistence in the face of introduced vector-borne diseases in Hawaii, where introduced avian malaria and introduced vectors have had a negative impact on most populations of Hawaiian forest birds for nearly a century. We studied birds, parasites, and vectors in nine study areas from 0 to 1,800 m on Mauna Loa Volcano, Hawaii from January to October, 2002. Contrary to predictions of prior work, we found that Hawaii amakihi (Hemignathus virens), a native species susceptible to malaria, comprised from 24.5% to 51.9% of the avian community at three low-elevation forests (55-270 m). Amakihi were more abundant at low elevations than at disease-free high elevations, and were resident and breeding there. Infection rates were 24-40% by microscopy and 55-83% by serology, with most infected individuals experiencing low-intensity, chronic infections. Mosquito trapping and diagnostics provided strong evidence for year-round local transmission. Moreover, we present evidence that Hawaii amakihi have increased in low elevation habitats on southeastern Hawaii Island over the past decade. The recent emergent phenomenon of recovering amakihi populations at low elevations, despite extremely high prevalence of avian malaria, suggests that ecological or evolutionary processes acting on hosts or parasites have allowed this species to recolonize low-elevation habitats. A better understanding of the mechanisms allowing coexistence of hosts and parasites may ultimately lead to tools for mitigating disease impacts on wildlife and human populations.

Host population persistence in the face of introduced vector-borne diseases: Hawaii amakihi and avian malaria

USGS Publications Warehouse

Woodworth, B.L.; Atkinson, C.T.; Lapointe, D.A.; Hart, P.J.; Spiegel, C.S.; Tweed, E.J.; Henneman, C.; LeBrun, J.; Denette, T.; DeMots, R.; Kozar, K.L.; Triglia, D.; Lease, Dan; Gregor, A.; Smith, T.; Duffy, D.

2005-01-01

The past quarter century has seen an unprecedented increase in the number of new and emerging infectious diseases throughout the world, with serious implications for human and wildlife populations. We examined host persistence in the face of introduced vector-borne diseases in Hawaii, where introduced avian malaria and introduced vectors have had a negative impact on most populations of Hawaiian forest birds for nearly a century. We studied birds, parasites, and vectors in nine study areas from 0 to 1,800 m on Mauna Loa Volcano, Hawaii from January to October, 2002. Contrary to predictions of prior work, we found that Hawaii amakihi (Hemignathus virens), a native species susceptible to malaria, comprised from 24.5% to 51.9% of the avian community at three low-elevation forests (55-270 m). Amakihi were more abundant at low elevations than at disease-free high elevations, and were resident and breeding there. Infection rates were 24-40% by microscopy and 55-83% by serology, with most infected individuals experiencing low-intensity, chronic infections. Mosquito trapping and diagnostics provided strong evidence for year-round local transmission. Moreover, we present evidence that Hawaii amakihi have increased in low elevation habitats on south-eastern Hawaii Island over the past decade. The recent emergent phenomenon of recovering amakihi populations at low elevations, despite extremely high prevalence of avian malaria, suggests that ecological or evolutionary processes acting on hosts or parasites have allowed this species to recolonize low-elevation habitats. A better understanding of the mechanisms allowing coexistence of hosts and parasites may ultimately lead to tools for mitigating disease impacts on wildlife and human populations.

Dispersal Pathways and Genetic Differentiation among Worldwide Populations of the Invasive Weed Centaurea solstitialis L. (Asteraceae)

PubMed Central

Eriksen, Renée L.; Hierro, José L.; Eren, Özkan; Andonian, Krikor; Török, Katalin; Becerra, Pablo I.; Montesinos, Daniel; Khetsuriani, Liana; Diaconu, Alecu; Kesseli, Rick

2014-01-01

The natural history of introduced species is often unclear due to a lack of historical records. Even when historical information is readily available, important factors of the invasions such as genetic bottlenecks, hybridization, historical relationships among populations and adaptive changes are left unknown. In this study, we developed a set of nuclear, simple sequence repeat markers and used these to characterize the genetic diversity and population structure among native (Eurasian) and non-native (North and South American) populations of Centaurea solstitialis L., (yellow starthistle). We used these data to test hypotheses about the invasion pathways of the species that were based on historical and geographical records, and we make inferences about historical relationships among populations and demographic processes following invasion. We confirm that the center of diversity and the native range of the species is likely the eastern Mediterranean region in the vicinity of Turkey. From this region, the species likely proceeded to colonize other parts of Europe and Asia via a slow, stepwise range expansion. Spanish populations were the primary source of seed to invade South America via human-mediated events, as was evident from historical records, but populations from the eastern Mediterranean region were also important. North American populations were largely derived from South America, but had secondary contributors. We suggest that the introduction history of non-native populations from disparate parts of the native range have allowed not just one, but multiple opportunities first in South America then again in North America for the creation of novel genotypes via intraspecific hybridization. We propose that multiple intraspecific hybridization events may have created especially potent conditions for the selection of a noxious invader, and may explain differences in genetic patterns among North and South America populations, inferred differences in demographic processes, as well as morphological differences previously reported from common garden experiments. PMID:25551223

Genetic diversity and population structure of sickleweed (Falcaria vulgaris; Apiaceae) in the upper Midwest USA

Treesearch

Sarbottam Piya; Madhav P. Nepal; Jack L. Butler; Gary E. Larson; Achal Neupane

2014-01-01

Sickleweed (Falcaria vulgaris), an introduced species native to Europe and Asia, grows as an aggressive weed in some areas of the upper Midwest in the United States. We are reporting genetic diversity and population structure of sickleweed populations using microsatellite markers and nuclear and chloroplast DNA sequences. Populations showed high genetic differentiation...

Survival of mountain quail translocated from two distinct source populations

USGS Publications Warehouse

Troy, Ronald J.; Coates, Peter S.; Connelly, John W.; Gillette, Gifford; Delehanty, David J.

2013-01-01

Translocation of mountain quail (Oreortyx pictus) to restore viable populations to their former range has become a common practice. Because differences in post-release vital rates between animals from multiple source populations has not been well studied, wildlife and land managers may arbitrarily choose the source population or base the source population on immediate availability when planning translocation projects. Similarly, an understanding of the optimal proportion of individuals from different age and sex classes for translocation would benefit translocation planning. During 2006 and 2007, we captured and translocated 125 mountain quail from 2 ecologically distinct areas: 38 from southern California and 87 from southwestern Oregon. We released mountain quail in the Bennett Hills of south-central Idaho. We radio-marked and monitored a subsample of 58 quail and used them for a 2-part survival analysis. Cumulative survival probability was 0.23 ± 0.05 (SE) at 150 days post-release. We first examined an a priori hypothesis (model) that survival varied between the 2 distinct source populations. We found that source population did not explain variation in survival. This result suggests that wildlife managers have flexibility in selecting source populations for mountain quail translocation efforts. In a post hoc examination, we pooled the quail across source populations and evaluated differences in survival probabilities between sex and age classes. The most parsimonious model indicated that adult male survival was substantially less than survival rates of other mountain quail age and sex classes (i.e., interaction between sex and age). This result suggests that translocation success could benefit by translocating yearling males rather than adult males, perhaps because adult male breeding behavior results in vulnerability to predators

40 CFR 421.95 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Plants Subcategory § 421.95 Pretreatment standards for existing sources. Except as provided in 40 CFR 403... standards for existing sources. The mass of wastewater pollutants in metallurgical acid plant blowdown introduced into a POTW shall not exceed the following values: Subpart I—Metallurgical Acid Plant—PSES...

40 CFR 421.95 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Plants Subcategory § 421.95 Pretreatment standards for existing sources. Except as provided in 40 CFR 403... standards for existing sources. The mass of wastewater pollutants in metallurgical acid plant blowdown introduced into a POTW shall not exceed the following values: Subpart I—Metallurgical Acid Plant—PSES...

An Exact Form of Lilley's Equation with a Velocity Quadrupole/Temperature Dipole Source Term

NASA Technical Reports Server (NTRS)

Goldstein, Marvin E.

2001-01-01

There have been several attempts to introduce approximations into the exact form of Lilley's equation in order to express the source term as the sum of a quadrupole whose strength is quadratic in the fluctuating velocities and a dipole whose strength is proportional to the temperature fluctuations. The purpose of this note is to show that it is possible to choose the dependent (i.e., the pressure) variable so that this type of result can be derived directly from the Euler equations without introducing any additional approximations.

Invasion of novel habitats uncouples haplo-diplontic life cycles.

PubMed

Krueger-Hadfield, Stacy A; Kollars, Nicole M; Byers, James E; Greig, Thomas W; Hammann, Mareike; Murray, David C; Murren, Courtney J; Strand, Allan E; Terada, Ryuta; Weinberger, Florian; Sotka, Erik E

2016-08-01

Baker's Law predicts uniparental reproduction will facilitate colonization success in novel habitats. While evidence supports this prediction among colonizing plants and animals, few studies have investigated shifts in reproductive mode in haplo-diplontic species in which both prolonged haploid and diploid stages separate meiosis and fertilization in time and space. Due to this separation, asexual reproduction can yield the dominance of one of the ploidy stages in colonizing populations. We tested for shifts in ploidy and reproductive mode across native and introduced populations of the red seaweed Gracilaria vermiculophylla. Native populations in the northwest Pacific Ocean were nearly always attached by holdfasts to hard substrata and, as is characteristic of the genus, haploid-diploid ratios were slightly diploid-biased. In contrast, along North American and European coastlines, introduced populations nearly always floated atop soft-sediment mudflats and were overwhelmingly dominated by diploid thalli without holdfasts. Introduced populations exhibited population genetic signals consistent with extensive vegetative fragmentation, while native populations did not. Thus, the ecological shift from attached to unattached thalli, ostensibly necessitated by the invasion of soft-sediment habitats, correlated with shifts from sexual to asexual reproduction and slight to strong diploid bias. We extend Baker's Law by predicting other colonizing haplo-diplontic species will show similar increases in asexuality that correlate with the dominance of one ploidy stage. Labile mating systems likely facilitate colonization success and subsequent range expansion, but for haplo-diplontic species, the long-term eco-evolutionary impacts will depend on which ploidy stage is lost and the degree to which asexual reproduction is canalized. © 2016 John Wiley & Sons Ltd.

BOOK REVIEW: NCRP Report No. 160: Ionizing Radiation Exposure of the Population of the United States NCRP Report No. 160: Ionizing Radiation Exposure of the Population of the United States

NASA Astrophysics Data System (ADS)

Thurston, Jim

2010-10-01

This report by Committee 6 of the Council is an extensive update of a previous report on the exposure of the US population to ionizing radiation sources from data gathered in the 1980s (published as Report 93 in 1987). It is combined with an update on the more in-depth assessment of data on medical exposures previously reported in 1989 (Report 100). Individual chapters in this new report are dedicated to specific sources of exposure to the US population—both from natural and artificial radiation—and the level of detail in each chapter is intended to reflect the significance of the contribution of each source to the total collective dose of the population. The first chapter is on the most significant contributor: background radiation. It expands on the concept of natural background radiation in Report 93, renaming it 'ubiquitous background', and describing in detail the contributions from both extra-terrestrial and terrestrial sources. The data demonstrates that the average dose from such exposure has varied little since the previous report (a slight increase from 3.0 mSv to 3.1 mSv). The next chapter is on medical radiation, i.e. the exposure to the population when attending as patients, not including occupational exposure to hospital workers. The most striking data published in the entire report is the increase in the contribution to the total US population dose attributed to such medical exposures. It is now as significant as that from background radiation: medical exposures now account for an average effective dose to the US citizen of 3.00 mSv, up from 0.53 mSv in 1992 (Report 100). The most important contribution to this increase is the 1.46 mSv from CT scanning alone. The nuclear medicine (including PET) contribution is up from 0.14 mSv to 0.77mSv. This evidently must be due to significant changes in medical radiological practice in the US tied to the increase in the availability of CT and PET imaging facilities. These increasing contributions have driven the overall average effective dose to a US citizen from approximately 3.6 mSv reported in 1987 to 6.2 mSv per annum, with medical exposures now responsible for 48% of the total (up from 15% in 1992). It is interesting to note that over roughly the same period of time, the total dose to the UK population has been revised upwards from 2.6 mSv to 2.7mSv to reflect (amongst other factors) the increase in CT scanning in the UK—obviously a much smaller change. However, one has to consider whether medical radiological practices in the UK might similarly change in the coming years, and UK population doses subsequently follow the US trend reported here. There is now a more detailed chapter on exposure to the population from consumer products and activities. Of the contributing factors in this category, the radiation dose received from radioactivity in tobacco smoke is the most significant, followed by building materials and air travel. There has been no significant change in the total dose received from these sources when compared to the earlier Report 93, at 0.13 mSv. The report also gives significant detail on exposure to the public from industrial sources (not just nuclear power), and discusses occupational exposure. Both these categories of exposure, averaged out of the whole population, give very small contributions to the total dose (0.003 mSv and 0.005 mSv, respectively). There are two final points to make about this report. Firstly, it continues the NCRP policy introduced for Report 93 of using SI units rather than the radiation units more commonly used within the US, hence making this report more readily accessible to an international audience. Secondly, in all the descriptions of the exposures and radiation doses received, no attempt is made to convert the doses into risk. The view of the Council, as stated in the forward to the report, is that attempting to quantify the risks associated with such levels of radiation exposure falls outside the remit of the Committee that prepared the report.

Epidemiology of Breast Cancer among Females in Basrah.

PubMed

S Habib, Omran; A Hameed, Lamis; A Ajeel, Narjis; Al-Hawaz, Mazin H; Al-Faddagh, Zaki A; N Nasr, Ghalib; Al-Sodani, Ali H; A Khalaf, Asaad; M Hasson, Hasson; Lname, Aida A; Abdul-Samad, Fname

2016-01-01

Breast cancer is the most frequent cancer in females. Its incidence is higher in developed countries than in developing ones partly due to variation in risk exposure and partly due to better detection methods. Scattered evidence in Basrah, Iraq, suggests that breast cancer has been increasing at a significant pace in recent years. This study aimed to measure the current level of risk of breast cancer among females in Basrah and to describe the time trend over almost a decade of years. Data on breast cancer cases from all sources of cancer registration in Basrah governorate were compiled for the years 2005-2012. The data for each year were first checked separately for duplicate reporting of cases among various sources. Then the eight files were pooled together and checked again for any duplicate cases among years of registration. The final set of data contained 2,284 cases of breast cancer (2,213 female cases and 71 male cases). All patients were inhabitants of Basrah governorate at the time of diagnosis. Figures on the Basrah population were obtained from various sources including the Ministry of Health, Ministry of Planning and Developmental Collaboration and local household surveys. It was possible to have total population estimates for each year and by age and sex. The data were imported into SPSS (version 17) software. Age specific and year specific incidence rates were calculated. The age standardized incidence rate was also calculated using world population as the standard population to be 34.9 per 100,000 females. Age-wise, no case was reported among children aged less than 15 years and the incidence increased with advancing age reaching a peak of 123.8/100,000 females at the age range of 50-54 years. The time trend of the crude incidence rate showed only modest increased risk with passage of years and no age shift could be documented in this study. Breast cancer in females in Basrah is a significant health problem. The current incidence rate (crude, 23.7/100,000, age-standardized, 34.9/100,000) is high and justifies intensive efforts to improve early detection of cases, provide better treatment amenities and introduce long term preventive measures. Using the age standardized incidence rate as reported in this paper, it is possible to put the risk in Basrah within a regional and international context.

Dynamic radioactive particle source

DOEpatents

Moore, Murray E; Gauss, Adam Benjamin; Justus, Alan Lawrence

2012-06-26

A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

Molybdenum enhanced low-temperature deposition of crystalline silicon nitride

DOEpatents

Lowden, Richard A.

1994-01-01

A process for chemical vapor deposition of crystalline silicon nitride which comprises the steps of: introducing a mixture of a silicon source, a molybdenum source, a nitrogen source, and a hydrogen source into a vessel containing a suitable substrate; and thermally decomposing the mixture to deposit onto the substrate a coating comprising crystalline silicon nitride containing a dispersion of molybdenum silicide.

Quantification of historical livestock importation into New Zealand 1860-1979.

PubMed

Binney, B M; Biggs, P J; Carter, P E; Holland, B R; Holland, B M; French, N P

2014-11-01

To quantify the numbers of live cattle, sheep and poultry imported into New Zealand and, where possible, their country of origin from 1860 to 1979. Information on the origin and number of live animal importations into New Zealand was collected for cattle, sheep and poultry for the period 1868-1979 from the annual reports compiled by the New Zealand Registrar General's Office, Government Statistician's Office, Census and Statistics Office, Census and Statistics Department, Customs Department and Department of Statistics. Census data from 1851 to 1871 were also used to estimate the livestock population during this period. The number of animals imported and the mean population for each species in a decade were determined, and the major countries of origin were identified. A large number of cattle (53,384) and sheep (604,525) were imported in the 1860s, and then there was a marked reduction in importations. Live poultry were imported in relatively small numbers (20,701) from 1880 to 1939, then 1,564,330 live poultry were imported between 1960 and 1979. Australia was the predominant country of origin for sheep between 1868 and 1959 (51,347/60,918; 84.3%) and of cattle between 1868 and 1979 (10,080/15,157; 66.5%). Only 6,712 (11.0%) sheep and 3,909 (25.8%) cattle were imported from the United Kingdom over the same periods, and even fewer from other countries. The collated data and historical reports show that from 1860 to 1979 Australia has been the main source of livestock introduced into New Zealand. The pattern of importation showed that large numbers of cattle and sheep were initially imported in the 1860s, probably in response to rapid agricultural expansion. Thereafter importations continued at much reduced numbers. In contrast, relatively small numbers of poultry were introduced until the 1960s when large numbers were imported as part of the development of a modern high-production industry. The overall pattern for both cattle and sheep was of a bottleneck event, as initially a relatively limited number of animals arrived from outside populations, followed by population expansion with ongoing but limited immigration (admixture). Investigation into the genetic population structure of New Zealand's cattle and sheep, as well as their host-associated microorganisms, could reflect the impact of these early historical events.

Construction of a Calibrated Probabilistic Classification Catalog: Application to 50k Variable Sources in the All-Sky Automated Survey

NASA Astrophysics Data System (ADS)

Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Brink, Henrik; Crellin-Quick, Arien

2012-12-01

With growing data volumes from synoptic surveys, astronomers necessarily must become more abstracted from the discovery and introspection processes. Given the scarcity of follow-up resources, there is a particularly sharp onus on the frameworks that replace these human roles to provide accurate and well-calibrated probabilistic classification catalogs. Such catalogs inform the subsequent follow-up, allowing consumers to optimize the selection of specific sources for further study and permitting rigorous treatment of classification purities and efficiencies for population studies. Here, we describe a process to produce a probabilistic classification catalog of variability with machine learning from a multi-epoch photometric survey. In addition to producing accurate classifications, we show how to estimate calibrated class probabilities and motivate the importance of probability calibration. We also introduce a methodology for feature-based anomaly detection, which allows discovery of objects in the survey that do not fit within the predefined class taxonomy. Finally, we apply these methods to sources observed by the All-Sky Automated Survey (ASAS), and release the Machine-learned ASAS Classification Catalog (MACC), a 28 class probabilistic classification catalog of 50,124 ASAS sources in the ASAS Catalog of Variable Stars. We estimate that MACC achieves a sub-20% classification error rate and demonstrate that the class posterior probabilities are reasonably calibrated. MACC classifications compare favorably to the classifications of several previous domain-specific ASAS papers and to the ASAS Catalog of Variable Stars, which had classified only 24% of those sources into one of 12 science classes.

CONSTRUCTION OF A CALIBRATED PROBABILISTIC CLASSIFICATION CATALOG: APPLICATION TO 50k VARIABLE SOURCES IN THE ALL-SKY AUTOMATED SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.

2012-12-15

With growing data volumes from synoptic surveys, astronomers necessarily must become more abstracted from the discovery and introspection processes. Given the scarcity of follow-up resources, there is a particularly sharp onus on the frameworks that replace these human roles to provide accurate and well-calibrated probabilistic classification catalogs. Such catalogs inform the subsequent follow-up, allowing consumers to optimize the selection of specific sources for further study and permitting rigorous treatment of classification purities and efficiencies for population studies. Here, we describe a process to produce a probabilistic classification catalog of variability with machine learning from a multi-epoch photometric survey. In additionmore » to producing accurate classifications, we show how to estimate calibrated class probabilities and motivate the importance of probability calibration. We also introduce a methodology for feature-based anomaly detection, which allows discovery of objects in the survey that do not fit within the predefined class taxonomy. Finally, we apply these methods to sources observed by the All-Sky Automated Survey (ASAS), and release the Machine-learned ASAS Classification Catalog (MACC), a 28 class probabilistic classification catalog of 50,124 ASAS sources in the ASAS Catalog of Variable Stars. We estimate that MACC achieves a sub-20% classification error rate and demonstrate that the class posterior probabilities are reasonably calibrated. MACC classifications compare favorably to the classifications of several previous domain-specific ASAS papers and to the ASAS Catalog of Variable Stars, which had classified only 24% of those sources into one of 12 science classes.« less

Microbial Penetration and Utilization of Organic Aircraft Fuel-Tank Coatings1

PubMed Central

Crum, M. G.; Reynolds, R. J.; Hedrick, H. G.

1967-01-01

Microorganisms have been found as contaminants in various types of aircraft fuel tanks. Their presence introduces problems in the operation of the aircraft, including destruction of components such as the organic coatings used as protective linings in the fuel tanks. Microbial penetration and utilization of the currently used organic coatings, EC 776, DV 1180, PR 1560, and DeSoto 1080, were determined by changes in electrical resistances of the coatings; mycelial weight changes; growth counts of the bacteria; and manometric determinations on Pseudomonas aeruginosa (GD-FW B-25) and Cladosporium resinae (QMC-7998). The results indicate EC 776 and DV 1180 to be less resistant to microbial degradation than the other coatings. Organic coatings, serving as a source of nutrition, would be conducive to population buildups in aircraft fuel tanks. Images Fig. 1 PMID:16349744

Stochastic Gain in Population Dynamics

NASA Astrophysics Data System (ADS)

Traulsen, Arne; Röhl, Torsten; Schuster, Heinz Georg

2004-07-01

We introduce an extension of the usual replicator dynamics to adaptive learning rates. We show that a population with a dynamic learning rate can gain an increased average payoff in transient phases and can also exploit external noise, leading the system away from the Nash equilibrium, in a resonancelike fashion. The payoff versus noise curve resembles the signal to noise ratio curve in stochastic resonance. Seen in this broad context, we introduce another mechanism that exploits fluctuations in order to improve properties of the system. Such a mechanism could be of particular interest in economic systems.

Parasites and marine invasions

USGS Publications Warehouse

Torchin, M.E.; Lafferty, K.D.; Kuris, A.M.

2002-01-01

Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by invasive species is often a result of the higher densities and larger sizes they attain compared to where they are native. A prominent hypothesis explaining the success of introduced species is that they are relatively free of the effects of natural enemies. Most notably, they may encounter fewer parasites in their introduced range compared to their native range. Parasites are ubiquitous and pervasive in marine systems, yet their role in marine invasions is relatively unexplored. Although data on parasites of marine organisms exist, the extent to which parasites can mediate marine invasions, or the extent to which invasive parasites and pathogens are responsible for infecting or potentially decimating native marine species have not been examined. In this review, we present a theoretical framework to model invasion success and examine the evidence for a relationship between parasite presence and the success of introduced marine species. For this, we compare the prevalence and species richness of parasites in several introduced populations of marine species with populations where they are native. We also discuss the potential impacts of introduced marine parasites on native ecosystems.

Multiple introductions boosted genetic diversity in the invasive range of black cherry (Prunus serotina; Rosaceae)

PubMed Central

Pairon, Marie; Petitpierre, Blaise; Campbell, Michael; Guisan, Antoine; Broennimann, Olivier; Baret, Philippe V.; Jacquemart, Anne-Laure; Besnard, Guillaume

2010-01-01

Background and Aims Black cherry (Prunus serotina) is a North American tree that is rapidly invading European forests. This species was introduced first as an ornamental plant then it was massively planted by foresters in many countries but its origins and the process of invasion remain poorly documented. Based on a genetic survey of both native and invasive ranges, the invasion history of black cherry was investigated by identifying putative source populations and then assessing the importance of multiple introductions on the maintenance of gene diversity. Methods Genetic variability and structure of 23 populations from the invasive range and 22 populations from the native range were analysed using eight nuclear microsatellite loci and five chloroplast DNA regions. Key Results Chloroplast DNA diversity suggests there were multiple introductions from a single geographic region (the north-eastern United States). A low reduction of genetic diversity was observed in the invasive range for both nuclear and plastid genomes. High propagule pressure including both the size and number of introductions shaped the genetic structure in Europe and boosted genetic diversity. Populations from Denmark, The Netherlands, Belgium and Germany showed high genetic diversity and low differentiation among populations, supporting the hypothesis that numerous introduction events, including multiple individuals and exchanges between sites, have taken place during two centuries of plantation. Conclusions This study postulates that the invasive black cherry has originated from east of the Appalachian Mountains (mainly the Allegheny plateau) and its invasiveness in north-western Europe is mainly due to multiple introductions containing high numbers of individuals. PMID:20400456

Do pathogens reduce genetic diversity of their hosts? Variable effects of sylvatic plague in black-tailed prairie dogs.

PubMed

Sackett, Loren C; Collinge, Sharon K; Martin, Andrew P

2013-05-01

Introduced diseases can cause dramatic declines in-and even the loss of-natural populations. Extirpations may be followed by low recolonization rates, leading to inbreeding and a loss of genetic variation, with consequences on population viability. Conversely, extirpations may create vacant habitat patches that individuals from multiple source populations can colonize, potentially leading to an influx of variation. We tested these alternative hypotheses by sampling 15 colonies in a prairie dog metapopulation during 7 years that encompassed an outbreak of sylvatic plague, providing the opportunity to monitor genetic diversity before, during and after the outbreak. Analysis of nine microsatellite loci revealed that within the metapopulation, there was no change in diversity. However, within extirpated colonies, patterns varied: In half of the colonies, allelic richness after recovery was less than the preplague conditions, and in the other half, richness was greater than the preplague conditions. Finally, analysis of variation within individuals revealed that prairie dogs present in recolonized colonies had higher heterozygosity than those present before plague. We confirmed plague survivorship in six founders; these individuals had significantly higher heterozygosity than expected by chance. Collectively, our results suggest that high immigration rates can maintain genetic variation at a regional scale despite simultaneous extirpations in spatially proximate populations. Thus, virulent diseases may increase genetic diversity of host populations by creating vacant habitats that allow an influx of genetic diversity. Furthermore, even highly virulent diseases may not eliminate individuals randomly; rather, they may selectively remove the most inbred individuals. © 2013 Blackwell Publishing Ltd.

Advanced backcross QTL mapping of resistance to Fusarium head blight and plant morphological traits in a Triticum macha × T. aestivum population.

PubMed

Buerstmayr, Maria; Lemmens, Marc; Steiner, Barbara; Buerstmayr, Hermann

2011-07-01

While many reports on genetic analysis of Fusarium head blight (FHB) resistance in bread wheat have been published during the past decade, only limited information is available on FHB resistance derived from wheat relatives. In this contribution, we report on the genetic analysis of FHB resistance derived from Triticum macha (Georgian spelt wheat). As the origin of T. macha is in the Caucasian region, it is supposed that its FHB resistance differs from other well-investigated resistance sources. To introduce valuable alleles from the landrace T. macha into a modern genetic background, we adopted an advanced backcross QTL mapping scheme. A backcross-derived recombinant-inbred line population of 321 BC(2)F(3) lines was developed from a cross of T. macha with the Austrian winter wheat cultivar Furore. The population was evaluated for Fusarium resistance in seven field experiments during four seasons using artificial inoculations. A total of 300 lines of the population were genetically fingerprinted using SSR and AFLP markers. The resulting linkage map covered 33 linkage groups with 560 markers. Five novel FHB-resistance QTL, all descending from T. macha, were found on four chromosomes (2A, 2B, 5A, 5B). Several QTL for morphological and developmental traits were mapped in the same population, which partly overlapped with FHB-resistance QTL. Only the 2BL FHB-resistance QTL co-located with a plant height QTL. The largest-effect FHB-resistance QTL in this population mapped at the spelt-type locus on chromosome 5A and was associated with the wild-type allele q, but it is unclear whether q has a pleiotropic effect on FHB resistance or is closely linked to a nearby resistance QTL.

Quantifying the Impact of Woodpecker Predation on Population Dynamics of the Emerald Ash Borer (Agrilus planipennis)

PubMed Central

Jennings, David E.; Gould, Juli R.; Vandenberg, John D.; Duan, Jian J.; Shrewsbury, Paula M.

2013-01-01

The emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that has killed millions of ash trees (Fraxinus spp.) since it was accidentally introduced to North America in the 1990s. Understanding how predators such as woodpeckers (Picidae) affect the population dynamics of EAB should enable us to more effectively manage the spread of this beetle, and toward this end we combined two experimental approaches to elucidate the relative importance of woodpecker predation on EAB populations. First, we examined wild populations of EAB in ash trees in New York, with each tree having a section screened to exclude woodpeckers. Second, we established experimental cohorts of EAB in ash trees in Maryland, and the cohorts on half of these trees were caged to exclude woodpeckers. The following spring these trees were debarked and the fates of the EAB larvae were determined. We found that trees from which woodpeckers were excluded consistently had significantly lower levels of predation, and that woodpecker predation comprised a greater source of mortality at sites with a more established wild infestation of EAB. Additionally, there was a considerable difference between New York and Maryland in the effect that woodpecker predation had on EAB population growth, suggesting that predation alone may not be a substantial factor in controlling EAB. In our experimental cohorts we also observed that trees from which woodpeckers were excluded had a significantly higher level of parasitism. The lower level of parasitism on EAB larvae found when exposed to woodpeckers has implications for EAB biological control, suggesting that it might be prudent to exclude woodpeckers from trees when attempting to establish parasitoid populations. Future studies may include utilizing EAB larval cohorts with a range of densities to explore the functional response of woodpeckers. PMID:24349520

Quantifying the impact of woodpecker predation on population dynamics of the emerald ash borer (Agrilus planipennis).

PubMed

Jennings, David E; Gould, Juli R; Vandenberg, John D; Duan, Jian J; Shrewsbury, Paula M

2013-01-01

The emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that has killed millions of ash trees (Fraxinus spp.) since it was accidentally introduced to North America in the 1990s. Understanding how predators such as woodpeckers (Picidae) affect the population dynamics of EAB should enable us to more effectively manage the spread of this beetle, and toward this end we combined two experimental approaches to elucidate the relative importance of woodpecker predation on EAB populations. First, we examined wild populations of EAB in ash trees in New York, with each tree having a section screened to exclude woodpeckers. Second, we established experimental cohorts of EAB in ash trees in Maryland, and the cohorts on half of these trees were caged to exclude woodpeckers. The following spring these trees were debarked and the fates of the EAB larvae were determined. We found that trees from which woodpeckers were excluded consistently had significantly lower levels of predation, and that woodpecker predation comprised a greater source of mortality at sites with a more established wild infestation of EAB. Additionally, there was a considerable difference between New York and Maryland in the effect that woodpecker predation had on EAB population growth, suggesting that predation alone may not be a substantial factor in controlling EAB. In our experimental cohorts we also observed that trees from which woodpeckers were excluded had a significantly higher level of parasitism. The lower level of parasitism on EAB larvae found when exposed to woodpeckers has implications for EAB biological control, suggesting that it might be prudent to exclude woodpeckers from trees when attempting to establish parasitoid populations. Future studies may include utilizing EAB larval cohorts with a range of densities to explore the functional response of woodpeckers.

The epidemiology of hepatitis C virus in Egypt: a systematic review and data synthesis

PubMed Central

2013-01-01

Background Egypt has the highest prevalence of hepatitis C virus (HCV) in the world, estimated nationally at 14.7%. Our study’s objective was to delineate the evidence on the epidemiology of HCV infection among the different population groups in Egypt, and to draw analytical inferences about the nature of HCV transmission in this country. Methods We conducted a systematic review of all data on HCV prevalence and incidence in Egypt following PRISMA guidelines. The main sources of data included PubMed and Embase databases. We also used a multivariate regression model to infer the temporal trend of HCV prevalence among the general population and high risk population in Egypt. Results We identified 150 relevant records, four of which were incidence studies. HCV incidence ranged from 0.8 to 6.8 per 1,000 person-years. Overall, HCV prevalence among pregnant women ranged between 5-15%, among blood donors between 5-25%, and among other general population groups between 0-40%. HCV prevalence among multi-transfused patients ranged between 10-55%, among dialysis patients between 50-90%, and among other high risk populations between 10% and 85%. HCV prevalence varied widely among other clinical populations and populations at intermediate risk. Risk factors appear to be parenteral anti-schistosomal therapy, injections, transfusions, and surgical procedures, among others. Results of our time trend analysis suggest that there is no evidence of a statistically significant decline in HCV prevalence over time in both the general population (p-value: 0.215) and high risk population (p-value: 0.426). Conclusions Egypt is confronted with an HCV disease burden of historical proportions that distinguishes this nation from others. A massive HCV epidemic at the national level must have occurred with substantial transmission still ongoing today. HCV prevention in Egypt must become a national priority. Policymakers, and public health and medical care stakeholders need to introduce and implement further prevention measures targeting the routes of HCV transmission. PMID:23799878

The population of faint Jupiter family comets near the Earth

NASA Astrophysics Data System (ADS)

Fernández, Julio A.; Morbidelli, Alessandro

2006-11-01

We study the population of faint Jupiter family comets (JFCs) that approach the Earth (perihelion distances q<1.3 AU) by applying a debiasing technique to the observed sample. We found for the debiased cumulative luminosity function (CLF) of absolute total magnitudes H a bimodal distribution in which brighter comets ( H≲9) follow a linear relation with a steep slope α=0.65±0.14, while fainter comets follow a much shallower slope α=0.25±0.06 down to H˜18. The slope can be pushed up to α=0.35±0.09 if a second break in the H distribution to a much shallower slope is introduced at H˜16. We estimate a population of about 10 3 faint JFCs with q<1.3 AU and 10

The Cross-Wavelet Transform and Analysis of Quasi-periodic Behavior in the Pearson-Readhead VLBI Survey Sources

NASA Astrophysics Data System (ADS)

Kelly, Brandon C.; Hughes, Philip A.; Aller, Hugh D.; Aller, Margo F.

2003-07-01

We introduce an algorithm for applying a cross-wavelet transform to analysis of quasi-periodic variations in a time series and introduce significance tests for the technique. We apply a continuous wavelet transform and the cross-wavelet algorithm to the Pearson-Readhead VLBI survey sources using data obtained from the University of Michigan 26 m paraboloid at observing frequencies of 14.5, 8.0, and 4.8 GHz. Thirty of the 62 sources were chosen to have sufficient data for analysis, having at least 100 data points for a given time series. Of these 30 sources, a little more than half exhibited evidence for quasi-periodic behavior in at least one observing frequency, with a mean characteristic period of 2.4 yr and standard deviation of 1.3 yr. We find that out of the 30 sources, there were about four timescales for every 10 time series, and about half of those sources showing quasi-periodic behavior repeated the behavior in at least one other observing frequency.

Optimal source coding, removable noise elimination, and natural coordinate system construction for general vector sources using replicator neural networks

NASA Astrophysics Data System (ADS)

Hecht-Nielsen, Robert

1997-04-01

A new universal one-chart smooth manifold model for vector information sources is introduced. Natural coordinates (a particular type of chart) for such data manifolds are then defined. Uniformly quantized natural coordinates form an optimal vector quantization code for a general vector source. Replicator neural networks (a specialized type of multilayer perceptron with three hidden layers) are the introduced. As properly configured examples of replicator networks approach minimum mean squared error (e.g., via training and architecture adjustment using randomly chosen vectors from the source), these networks automatically develop a mapping which, in the limit, produces natural coordinates for arbitrary source vectors. The new concept of removable noise (a noise model applicable to a wide variety of real-world noise processes) is then discussed. Replicator neural networks, when configured to approach minimum mean squared reconstruction error (e.g., via training and architecture adjustment on randomly chosen examples from a vector source, each with randomly chosen additive removable noise contamination), in the limit eliminate removable noise and produce natural coordinates for the data vector portions of the noise-corrupted source vectors. Consideration regarding selection of the dimension of a data manifold source model and the training/configuration of replicator neural networks are discussed.

Molybdenum enhanced low-temperature deposition of crystalline silicon nitride

DOEpatents

Lowden, R.A.

1994-04-05

A process for chemical vapor deposition of crystalline silicon nitride is described which comprises the steps of: introducing a mixture of a silicon source, a molybdenum source, a nitrogen source, and a hydrogen source into a vessel containing a suitable substrate; and thermally decomposing the mixture to deposit onto the substrate a coating comprising crystalline silicon nitride containing a dispersion of molybdenum silicide. 5 figures.

Indirect effects of introduced trout on Cascades frogs (Rana cascadae) via shared aquatic prey

Treesearch

Maxwell B. Joseph; Jonah Piovia-Scott; Sharon P. Lawler; Karen L. Pope

2010-01-01

1. The introduction of trout to montane lakes has negatively affected amphibian populations across the western United States. In northern California’s Klamath–Siskiyou Mountains, introduced trout have diminished the distribution and abundance of a native ranid frog, Rana (=Lithobates)

Temporal Genetic Dynamics of an Invasive Species, Frankliniella occidentalis (Pergande), in an Early Phase of Establishment.

PubMed

Yang, Xian-Ming; Lou, Heng; Sun, Jing-Tao; Zhu, Yi-Ming; Xue, Xiao-Feng; Hong, Xiao-Yue

2015-07-03

Many species can successfully colonize new areas despite their propagules having low genetic variation. We assessed whether the decreased genetic diversity could result in temporal fluctuations of genetic parameters of the new populations of an invasive species, western flower thrips, Frankliniella occidentalis, using mitochondrial and microsatellite markers. This study was conducted in eight localities from four climate regions in China, where F. occidentalis was introduced in the year 2000 and had lower genetic diversity than its native populations. We also tested the level of genetic differentiation in these introduced populations. The genetic diversity of the samples at different years in the same locality was not significantly different from each other in most localities. FST and STRUCTURE analysis also showed that most temporal population comparisons from the same sites were not significantly differentiated. Our results showed that the invasive populations of F. occidentalis in China can maintain temporal stability in genetic composition at an early phase of establishment despite having lower genetic diversity than in their native range.

Bayesian Methods for the Physical Sciences. Learning from Examples in Astronomy and Physics.

NASA Astrophysics Data System (ADS)

Andreon, Stefano; Weaver, Brian

2015-05-01

Chapter 1: This chapter presents some basic steps for performing a good statistical analysis, all summarized in about one page. Chapter 2: This short chapter introduces the basics of probability theory inan intuitive fashion using simple examples. It also illustrates, again with examples, how to propagate errors and the difference between marginal and profile likelihoods. Chapter 3: This chapter introduces the computational tools and methods that we use for sampling from the posterior distribution. Since all numerical computations, and Bayesian ones are no exception, may end in errors, we also provide a few tips to check that the numerical computation is sampling from the posterior distribution. Chapter 4: Many of the concepts of building, running, and summarizing the resultsof a Bayesian analysis are described with this step-by-step guide using a basic (Gaussian) model. The chapter also introduces examples using Poisson and Binomial likelihoods, and how to combine repeated independent measurements. Chapter 5: All statistical analyses make assumptions, and Bayesian analyses are no exception. This chapter emphasizes that results depend on data and priors (assumptions). We illustrate this concept with examples where the prior plays greatly different roles, from major to negligible. We also provide some advice on how to look for information useful for sculpting the prior. Chapter 6: In this chapter we consider examples for which we want to estimate more than a single parameter. These common problems include estimating location and spread. We also consider examples that require the modeling of two populations (one we are interested in and a nuisance population) or averaging incompatible measurements. We also introduce quite complex examples dealing with upper limits and with a larger-than-expected scatter. Chapter 7: Rarely is a sample randomly selected from the population we wish to study. Often, samples are affected by selection effects, e.g., easier-to-collect events or objects are over-represented in samples and difficult-to-collect are under-represented if not missing altogether. In this chapter we show how to account for non-random data collection to infer the properties of the population from the studied sample. Chapter 8: In this chapter we introduce regression models, i.e., how to fit (regress) one, or more quantities, against each other through a functional relationship and estimate any unknown parameters that dictate this relationship. Questions of interest include: how to deal with samples affected by selection effects? How does a rich data structure influence the fitted parameters? And what about non-linear multiple-predictor fits, upper/lower limits, measurements errors of different amplitudes and an intrinsic variety in the studied populations or an extra source of variability? A number of examples illustrate how to answer these questions and how to predict the value of an unavailable quantity by exploiting the existence of a trend with another, available, quantity. Chapter 9: This chapter provides some advice on how the careful scientist should perform model checking and sensitivity analysis, i.e., how to answer the following questions: is the considered model at odds with the current available data (the fitted data), for example because it is over-simplified compared to some specific complexity pointed out by the data? Furthermore, are the data informative about the quantity being measured or are results sensibly dependent on details of the fitted model? And, finally, what about if assumptions are uncertain? A number of examples illustrate how to answer these questions. Chapter 10: This chapter compares the performance of Bayesian methods against simple, non-Bayesian alternatives, such as maximum likelihood, minimal chi square, ordinary and weighted least square, bivariate correlated errors and intrinsic scatter, and robust estimates of location and scale. Performances are evaluated in terms of quality of the prediction, accuracy of the estimates, and fairness and noisiness of the quoted errors. We also focus on three failures of maximum likelihood methods occurring with small samples, with mixtures, and with regressions with errors in the predictor quantity.

Factors Influencing F/OSS Cloud Computing Software Product Success: A Quantitative Study

ERIC Educational Resources Information Center

Letort, D. Brian

2012-01-01

Cloud Computing introduces a new business operational model that allows an organization to shift information technology consumption from traditional capital expenditure to operational expenditure. This shift introduces challenges from both the adoption and creation vantage. This study evaluates factors that influence Free/Open Source Software…

'Bee hotels' as tools for native pollinator conservation: a premature verdict?

PubMed

MacIvor, J Scott; Packer, Laurence

2015-01-01

Society is increasingly concerned with declining wild bee populations. Although most bees nest in the ground, considerable effort has centered on installing 'bee hotels'--also known as nest boxes or trap nests--which artificially aggregate nest sites of above ground nesting bees. Campaigns to 'save the bees' often promote these devices despite the absence of data indicating they have a positive effect. From a survey of almost 600 bee hotels set up over a period of three years in Toronto, Canada, introduced bees nested at 32.9% of sites and represented 24.6% of more than 27,000 total bees and wasps recorded (47.1% of all bees recorded). Native bees were parasitized more than introduced bees and females of introduced bee species provisioned nests with significantly more female larva each year. Native wasps were significantly more abundant than both native and introduced bees and occupied almost 3/4 of all bee hotels each year; further, introduced wasps were the only group to significantly increase in relative abundance year over year. More research is needed to elucidate the potential pitfalls and benefits of using bee hotels in the conservation and population dynamics of wild native bees.

‘Bee Hotels’ as Tools for Native Pollinator Conservation: A Premature Verdict?

PubMed Central

MacIvor, J. Scott; Packer, Laurence

2015-01-01

Society is increasingly concerned with declining wild bee populations. Although most bees nest in the ground, considerable effort has centered on installing ‘bee hotels’—also known as nest boxes or trap nests—which artificially aggregate nest sites of above ground nesting bees. Campaigns to ‘save the bees’ often promote these devices despite the absence of data indicating they have a positive effect. From a survey of almost 600 bee hotels set up over a period of three years in Toronto, Canada, introduced bees nested at 32.9% of sites and represented 24.6% of more than 27,000 total bees and wasps recorded (47.1% of all bees recorded). Native bees were parasitized more than introduced bees and females of introduced bee species provisioned nests with significantly more female larva each year. Native wasps were significantly more abundant than both native and introduced bees and occupied almost 3/4 of all bee hotels each year; further, introduced wasps were the only group to significantly increase in relative abundance year over year. More research is needed to elucidate the potential pitfalls and benefits of using bee hotels in the conservation and population dynamics of wild native bees. PMID:25785609

Spatial variation in anthropogenic mortality induces a source-sink system in a hunted mesopredator.

PubMed

Minnie, Liaan; Zalewski, Andrzej; Zalewska, Hanna; Kerley, Graham I H

2018-04-01

Lethal carnivore management is a prevailing strategy to reduce livestock predation. Intensity of lethal management varies according to land-use, where carnivores are more intensively hunted on farms relative to reserves. Variations in hunting intensity may result in the formation of a source-sink system where carnivores disperse from high-density to low-density areas. Few studies quantify dispersal between supposed sources and sinks-a fundamental requirement for source-sink systems. We used the black-backed jackal (Canis mesomelas) as a model to determine if heterogeneous anthropogenic mortality induces a source-sink system. We analysed 12 microsatellite loci from 554 individuals from lightly hunted and previously unhunted reserves, as well as heavily hunted livestock- and game farms. Bayesian genotype assignment showed that jackal populations displayed a hierarchical population structure. We identified two genetically distinct populations at the regional level and nine distinct subpopulations at the local level, with each cluster corresponding to distinct land-use types separated by various dispersal barriers. Migration, estimated using Bayesian multilocus genotyping, between reserves and farms was asymmetric and heterogeneous anthropogenic mortality induced source-sink dynamics via compensatory immigration. Additionally some heavily hunted populations also acted as source populations, exporting individuals to other heavily hunted populations. This indicates that heterogeneous anthropogenic mortality results in the formation of a complex series of interconnected sources and sinks. Thus, lethal management of mesopredators may not be an effective long-term strategy in reducing livestock predation, as dispersal and, more importantly, compensatory immigration may continue to affect population reduction efforts as long as dispersal from other areas persists.

Optional contributions have positive effects for volunteering public goods games

NASA Astrophysics Data System (ADS)

Song, Qi-Qing; Li, Zhen-Peng; Fu, Chang-He; Wang, Lai-Sheng

2011-11-01

Public goods (PG) games with the volunteering mechanism are referred to as volunteering public goods (VPG) games, in which loners are introduced to the PG games, and a loner obtains a constant payoff but not participating the game. Considering that small contributions may have positive effects to encourage more players with bounded rationality to contribute, this paper introduces optional contributions (high value or low value) to these typical VPG games-a cooperator can contribute a high or low payoff to the public pools. With the low contribution, the logit dynamics show that cooperation can be promoted in a well mixed population comparing to the typical VPG games, furthermore, as the multiplication factor is greater than a threshold, the average payoff of the population is also enhanced. In spatial VPG games, we introduce a new adjusting mechanism that is an approximation to best response. Some results in agreement with the prediction of the logit dynamics are found. These simulation results reveal that for VPG games the option of low contributions may be a better method to stimulate the growth of cooperation frequency and the average payoff of the population.

Manipulation of the fertility of marsupials for conservation of endangered species and control of over-abundant populations.

PubMed

Mate, K E; Molinia, F C; Rodger, J C

1998-10-01

Marsupials present a dichotomy in population management; the numbers of many Australian marsupial species have declined due to loss of habitat, competition from introduced herbivores and predation by introduced carnivores, but other species have become locally overabundant in Australia or are introduced pests in New Zealand. The manipulation of reproduction offers the means to increase or decrease productivity; however, considerable fundamental research is required before reproductive technologies can be applied to marsupials. Marsupials differ from eutherian mammals in several aspects of their reproduction including sex differentiation, gamete function and endocrinology, as well as in the relative lengths of gestation and lactation. Although these differences present unique problems in the application of reproductive technologies to marsupials, they also present unique opportunities for marsupial-specific fertility control. This paper summarises the assisted breeding technologies currently being applied to marsupials including superovulation, artificial insemination, in vitro fertilization and gene banking; unique marsupial targets for contraceptive intervention including gamete production, sperm capacitation, gamete surface antigens and embryonic development; and some options for the delivery of contraceptive vaccines to marsupial populations.

ChromatoGate: A Tool for Detecting Base Mis-Calls in Multiple Sequence Alignments by Semi-Automatic Chromatogram Inspection

PubMed Central

Alachiotis, Nikolaos; Vogiatzi, Emmanouella; Pavlidis, Pavlos; Stamatakis, Alexandros

2013-01-01

Automated DNA sequencers generate chromatograms that contain raw sequencing data. They also generate data that translates the chromatograms into molecular sequences of A, C, G, T, or N (undetermined) characters. Since chromatogram translation programs frequently introduce errors, a manual inspection of the generated sequence data is required. As sequence numbers and lengths increase, visual inspection and manual correction of chromatograms and corresponding sequences on a per-peak and per-nucleotide basis becomes an error-prone, time-consuming, and tedious process. Here, we introduce ChromatoGate (CG), an open-source software that accelerates and partially automates the inspection of chromatograms and the detection of sequencing errors for bidirectional sequencing runs. To provide users full control over the error correction process, a fully automated error correction algorithm has not been implemented. Initially, the program scans a given multiple sequence alignment (MSA) for potential sequencing errors, assuming that each polymorphic site in the alignment may be attributed to a sequencing error with a certain probability. The guided MSA assembly procedure in ChromatoGate detects chromatogram peaks of all characters in an alignment that lead to polymorphic sites, given a user-defined threshold. The threshold value represents the sensitivity of the sequencing error detection mechanism. After this pre-filtering, the user only needs to inspect a small number of peaks in every chromatogram to correct sequencing errors. Finally, we show that correcting sequencing errors is important, because population genetic and phylogenetic inferences can be misled by MSAs with uncorrected mis-calls. Our experiments indicate that estimates of population mutation rates can be affected two- to three-fold by uncorrected errors. PMID:24688709

ChromatoGate: A Tool for Detecting Base Mis-Calls in Multiple Sequence Alignments by Semi-Automatic Chromatogram Inspection.

PubMed

Alachiotis, Nikolaos; Vogiatzi, Emmanouella; Pavlidis, Pavlos; Stamatakis, Alexandros

2013-01-01

Automated DNA sequencers generate chromatograms that contain raw sequencing data. They also generate data that translates the chromatograms into molecular sequences of A, C, G, T, or N (undetermined) characters. Since chromatogram translation programs frequently introduce errors, a manual inspection of the generated sequence data is required. As sequence numbers and lengths increase, visual inspection and manual correction of chromatograms and corresponding sequences on a per-peak and per-nucleotide basis becomes an error-prone, time-consuming, and tedious process. Here, we introduce ChromatoGate (CG), an open-source software that accelerates and partially automates the inspection of chromatograms and the detection of sequencing errors for bidirectional sequencing runs. To provide users full control over the error correction process, a fully automated error correction algorithm has not been implemented. Initially, the program scans a given multiple sequence alignment (MSA) for potential sequencing errors, assuming that each polymorphic site in the alignment may be attributed to a sequencing error with a certain probability. The guided MSA assembly procedure in ChromatoGate detects chromatogram peaks of all characters in an alignment that lead to polymorphic sites, given a user-defined threshold. The threshold value represents the sensitivity of the sequencing error detection mechanism. After this pre-filtering, the user only needs to inspect a small number of peaks in every chromatogram to correct sequencing errors. Finally, we show that correcting sequencing errors is important, because population genetic and phylogenetic inferences can be misled by MSAs with uncorrected mis-calls. Our experiments indicate that estimates of population mutation rates can be affected two- to three-fold by uncorrected errors.

Out of Asia: mitochondrial evolutionary history of the globally introduced supralittoral isopod Ligia exotica.

PubMed

Hurtado, Luis A; Mateos, Mariana; Wang, Chang; Santamaria, Carlos A; Jung, Jongwoo; Khalaji-Pirbalouty, Valiallah; Kim, Won

2018-01-01

The native ranges and invasion histories of many marine species remain elusive due to a dynamic dispersal process via marine vessels. Molecular markers can aid in identification of native ranges and elucidation of the introduction and establishment process. The supralittoral isopod Ligia exotica has a wide tropical and subtropical distribution, frequently found in harbors and ports around the globe. This isopod is hypothesized to have an Old World origin, from where it was unintentionally introduced to other regions via wooden ships and solid ballast. Its native range, however, remains uncertain. Recent molecular studies uncovered the presence of two highly divergent lineages of L. exotica in East Asia, and suggest this region is a source of nonindigenous populations. In this study, we conducted phylogenetic analyses (Maximum Likelihood and Bayesian) of a fragment of the mitochondrial 16S ribosomal (r)DNA gene using a dataset of this isopod that greatly expanded previous representation from Asia and putative nonindigenous populations around the world. For a subset of samples, sequences of 12S rDNA and NaK were also obtained and analyzed together with 16S rDNA. Our results show that L. exotica is comprised of several highly divergent genetic lineages, which probably represent different species. Most of the 16S rDNA genetic diversity (48 haplotypes) was detected in East and Southeast Asia. Only seven haplotypes were observed outside this region (in the Americas, Hawai'i, Africa and India), which were identical or closely related to haplotypes found in East and Southeast Asia. Phylogenetic patterns indicate the L. exotica clade originated and diversified in East and Southeast Asia, and only members of one of the divergent lineages have spread out of this region, recently, suggesting the potential to become invasive is phylogenetically constrained.

Introduced species and management of a Nothofagus/Austrocedrus forest.

PubMed

Simberloff, Daniel; Relva, Maria Andrea; Nunez, Martin

2003-02-01

Isla Victoria (Nahuel Huapi National Park, Argentina), a large island dominated by native Nothofagus and Austrocedrus forest, has old plantations of many introduced tree species, some of which are famed invaders of native ecosystems elsewhere. There are also large populations of introduced deer and shrubs that may interact in a complex way with the introduced trees, as well as a recently arrived population of wild boar. Long-standing concern that the introduced trees will invade and transform native forest may be unwarranted, as there is little evidence of progressive invasion, even close to the plantations, despite over 50 years of opportunity. Introduced and native shrubs allow scattered introduced trees to achieve substantial size in abandoned pastures, but in almost all areas neither the trees nor the shrubs appear to be spreading beyond these sites. These shrub communities may be stable rather than successional, but the technology for restoring them to native forest is uncertain and probably currently impractical. Any attempt to remove the exotic tree seedlings and saplings from native forest would probably create the very conditions that would favor colonization by exotic plants rather than native trees, while simply clear-cutting the plantations would be unlikely to lead to regeneration of Nothofagus or Austrocedrus. The key to maintaining native forest is preventing catastrophic fire, as several introduced trees and shrubs would be favored over native dominant trees in recolonization. Deer undoubtedly interact with both native and introduced trees and shrubs, but their net effect on native forest is not yet clear, and specific management of deer beyond the current hunting by staff is unwarranted, at least if preventing tree invasion is the goal. The steep terrain and shallow soil make the recently arrived boar a grave threat to the native forest. Eradication is probably feasible and should be attempted quickly.

Present status of Maconellicoccus hirsutus (Hemiptera: Pseudococcidae) in the Mariana Islands and its control by two fortuitously introduced natural enemies.

PubMed

Reddy, G V P; Muniappan, R; Cruz, Z T; Naz, F; Bamba, J P; Tenorio, J

2009-08-01

The mealybug Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae), attacks ornamental and fruit crops in the Mariana Islands. Insecticides cannot penetrate the heavy layers of wax that protect the insect's body. We surveyed the mealybug's locally recruited natural enemies and their effects on its population on Guam, Rota, Saipan, and Tinian to assess the need for introduction of exotic natural enemies. We monitored population densities of M. hirsutus, those of its natural enemies, and parasitism rates for 3 yr, 2005-2007. Our surveys revealed the presence of two parasitoids, Anagyrus kamali Moursi (Hymenoptera: Encyrtidae) and Allotropa sp. near mecrida (Walker) (Hymenoptera: Platygastridae), fortuitously introduced to the Mariana Islands with M. hirsutus. The predator Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) also was often found feeding on M. hirsutus. Population density of M. hirsutus was below the economic threshold at all locations. Rainfall seemed to affect mean numbers of M. hirsutus and mean numbers of eggs at some locations. On all four islands, the two parasitoids, complemented by the predator, were effectively controlling the M. hirsutus population. No evidence of hyperparasitism was recorded. Currently, economic damage by M. hirsutus is not a concern in the Mariana Islands, and additional parasitoids need not be introduced to control M. hirsutus.

Introducing Human Sexuality into the Population Education Curriculum. The State-of-the-Art. Population Education Research Utilization Monograph Series 1 Part 3.

ERIC Educational Resources Information Center

Villanueva, Carmelita L.; Arellano-Reyes, Ma. Felicitas

This paper explores one problem area that hampers the introduction and acceptance of sex education in schools. Specifically, the paper reviews problems related to the human sexuality component of population education programs in the Philippines. Research on the experiences of the Population Education Program (PEP) is discussed, as well as research…

Taking a Population Census, Episode IV. Resource Material Development: Population Dynamics in Eighth Grade American History.

ERIC Educational Resources Information Center

Massialas, Byron G.; And Others

This is the fourth unit in a series that introduces population concepts into the eighth grade American history curriculum. (See SO 013 782 for an overview of the guide.) In Episode IV, the history topic is union under the Constitution. Objectives are to (1) help the student to examine the need for collecting information on the population during…

Specificity of extrafloral nectar induction by herbivores differs among native and invasive populations of tallow tree

USDA-ARS?s Scientific Manuscript database

Invasive plants are released from specialist herbivores and encounter novel generalists in their introduced ranges so their defenses may vary between native and introduced ranges. But few studies have examined how constitutive and induced indirect defenses change during plant invasion. We compared t...

A Model of Differential Amygdala Activation in Psychopathy

ERIC Educational Resources Information Center

Moul, Caroline; Killcross, Simon; Dadds, Mark R.

2012-01-01

This article introduces a novel hypothesis regarding amygdala function in psychopathy. The first part of this article introduces the concept of psychopathy and describes the main cognitive and affective impairments demonstrated by this population; that is, a deficit in fear-recognition, lower conditioned fear responses and poor performance in…

Extinction of an introduced warm-climate alien species, Xenopus laevis, by extreme weather events.

PubMed

Tinsley, Richard C; Stott, Lucy C; Viney, Mark E; Mable, Barbara K; Tinsley, Matthew C

Invasive, non-native species represent a major threat to biodiversity worldwide. The African amphibian Xenopus laevis is widely regarded as an invasive species and a threat to local faunas. Populations originating at the Western Cape, South Africa, have been introduced on four continents, mostly in areas with a similar Mediterranean climate. Some introduced populations are also established in cooler environments where persistence for many decades suggests a capacity for long-term adaptation. In these cases, recent climate warming might enhance invasion ability, favouring range expansion, population growth and negative effects on native faunas. In the cool temperate UK, populations have been established for about 50 years in Wales and for an unknown period, probably >20 years, in England (Lincolnshire). Our field studies over 30 and 10 years, respectively, show that in favourable conditions there may be good recruitment, fast individual growth rates and large body size; maximum longevity exceeds 23 years. Nevertheless, areas of distribution remained limited, with numbers <500 in each population. In 2010, only a single individual was captured at each locality and further searching failed to record any others in repeated sampling up to 2014. We conclude that both populations are now extinct. The winters of 2009-2010 and 2010-2011 experienced extreme cold and drought (December 2010 was the coldest in 120 years and the third driest in 100 years). The extinction of X. laevis in these areas indicates that even relatively long-established alien species remain vulnerable to rare extreme weather conditions.

Survival and reproduction of myxobolus cerebralis-resistant Rainbow Trout introduced to the colorado river and increased resistance of age-0 progeny

USGS Publications Warehouse

Winkelman, Dana L.; Fetherman, Eric R.; Baerwald, Melinda R.; Schisler, George J.

2014-01-01

Myxobolus cerebralis caused severe declines in rainbow trout populations across Colorado following its introduction in the 1980s. One promising approach for the recovery of Colorado’s rainbow trout populations has been the production of rainbow trout that are genetically resistant to the parasite. We introduced one of these resistant crosses, known as the GR×CRR (cross between the German Rainbow [GR] and Colorado River Rainbow [CRR] trout strains), to the upper Colorado River. The abundance, survival, and growth of the stocked GR×CRR population was examined to determine if GR×CRRs had contributed offspring to the age-0 population, and determine whether these offspring displayed increased resistance and survival characteristics compared to their wild CRR counterparts. Apparent survival of the introduced GR×CRR over the entire study period was estimated to be 0.007 (±0.001). Despite low survival of the GR×CRRs, age-0 progeny of the GR×CRR were encountered in years 2008 through 2011. Genetic assignments revealed a shift in the genetic composition of the rainbow trout fry population over time, with CRR fish comprising the entirety of the fry population in 2007, and GR-cross fish comprising nearly 80% of the fry population in 2011. A decrease in average infection severity (myxospores fish−1) was observed concurrent with the shift in the genetic composition of the rainbow trout fry population, decreasing from an average of 47,708 (±8,950) myxospores fish−1 in 2009 to 2,672 (±4,379) myxospores fish−1 in 2011. Results from this experiment suggest that the GR×CRR can survive and reproduce in rivers with a high prevalence of M. cerebralis. In addition, reduced myxospore burdens in age-0 fish indicated that stocking this cross may ultimately lead to an overall reduction in infection prevalence and severity in the salmonid populations of the upper Colorado River.

Survival and Reproduction of Myxobolus cerebralis-Resistant Rainbow Trout Introduced to the Colorado River and Increased Resistance of Age-0 Progeny

PubMed Central

Fetherman, Eric R.; Winkelman, Dana L.; Baerwald, Melinda R.; Schisler, George J.

2014-01-01

Myxobolus cerebralis caused severe declines in rainbow trout populations across Colorado following its introduction in the 1980s. One promising approach for the recovery of Colorado’s rainbow trout populations has been the production of rainbow trout that are genetically resistant to the parasite. We introduced one of these resistant crosses, known as the GR×CRR (cross between the German Rainbow [GR] and Colorado River Rainbow [CRR] trout strains), to the upper Colorado River. The abundance, survival, and growth of the stocked GR×CRR population was examined to determine if GR×CRRs had contributed offspring to the age-0 population, and determine whether these offspring displayed increased resistance and survival characteristics compared to their wild CRR counterparts. Apparent survival of the introduced GR×CRR over the entire study period was estimated to be 0.007 (±0.001). Despite low survival of the GR×CRRs, age-0 progeny of the GR×CRR were encountered in years 2008 through 2011. Genetic assignments revealed a shift in the genetic composition of the rainbow trout fry population over time, with CRR fish comprising the entirety of the fry population in 2007, and GR-cross fish comprising nearly 80% of the fry population in 2011. A decrease in average infection severity (myxospores fish−1) was observed concurrent with the shift in the genetic composition of the rainbow trout fry population, decreasing from an average of 47,708 (±8,950) myxospores fish−1 in 2009 to 2,672 (±4,379) myxospores fish−1 in 2011. Results from this experiment suggest that the GR×CRR can survive and reproduce in rivers with a high prevalence of M. cerebralis. In addition, reduced myxospore burdens in age-0 fish indicated that stocking this cross may ultimately lead to an overall reduction in infection prevalence and severity in the salmonid populations of the upper Colorado River. PMID:24811066

Coherent optical processing using noncoherent light after source masking.

PubMed

Boopathi, V; Vasu, R M

1992-01-10

Coherent optical processing starting with spatially noncoherent illumination is described. Good spatial coherence is introduced in the far field by modulating a noncoherent source when masks with sharp autocorrelation are used. The far-field mutual coherence function of light is measured and it is seen that, for the masks and the source size used here, we get a fairly large area over which the mutual coherence function is high and flat. We demonstrate traditional coherent processing operations such as Fourier transformation and image deblurring when coherent light that is produced in the above fashion is used. A coherence-redundancy merit function is defined for this type of processing system. It is experimentally demonstrated that the processing system introduced here has superior blemish tolerance compared with a traditional processor that uses coherent illumination.

About the Modeling of Radio Source Time Series as Linear Splines

NASA Astrophysics Data System (ADS)

Karbon, Maria; Heinkelmann, Robert; Mora-Diaz, Julian; Xu, Minghui; Nilsson, Tobias; Schuh, Harald

2016-12-01

Many of the time series of radio sources observed in geodetic VLBI show variations, caused mainly by changes in source structure. However, until now it has been common practice to consider source positions as invariant, or to exclude known misbehaving sources from the datum conditions. This may lead to a degradation of the estimated parameters, as unmodeled apparent source position variations can propagate to the other parameters through the least squares adjustment. In this paper we will introduce an automated algorithm capable of parameterizing the radio source coordinates as linear splines.

Using Primary Sources on the Internet To Teach and Learn History. ERIC Digest.

ERIC Educational Resources Information Center

Shiroma, Deanne

The Internet enables teachers to enhance the teaching and learning of history through quick and extensive access to primary sources. Introducing and using primary sources in the history classroom will almost certainly lead to active learning and development of critical thinking, reasoning, and problem solving. This Digest discusses: (1) types and…

Abundance and activity of 16S rRNA, amoA and nifH bacterial genes during assisted phytostabilization of mine tailings

PubMed Central

Nelson, Karis N.; Neilson, Julia W.; Root, Robert A.; Chorover, Jon; Maier, Raina M.

2014-01-01

Mine tailings in semiarid regions are highly susceptible to erosion and are sources of dust pollution and potential avenues of human exposure to toxic metals. One constraint to revegetation of tailings by phytostabilization is the absence of microbial communities critical for biogeochemical cycling of plant nutrients. The objective of this study was to evaluate specific genes as in situ indicators of biological soil response during phytoremediation. The abundance and activity of 16S rRNA, nifH, and amoA were monitored during a nine month phytostabilization study using buffalo grass and quailbush grown in compost-amended, metalliferous tailings. The compost amendment provided a greater than 5-log increase in bacterial abundance, and survival of this compost-inoculum was more stable in planted treatments. Despite increased abundance, the activity of the introduced community was low, and significant increases were not detected until six and nine months in quailbush, and unplanted compost and buffalo grass treatments, respectively. In addition, increased abundances of nitrogen-fixation (nifH) and ammonia-oxidizing (amoA) genes were observed in rhizospheres of buffalo grass and quailbush, respectively. Thus, plant establishment facilitated the short term stabilization of introduced bacterial biomass and supported the growth of two key nitrogen-cycling populations in compost-amended tailings. PMID:25495940

Spatial and temporal spawning dynamics of native westslope cutthroat trout, Oncorhynchus clarkii lewisi, introduced rainbow trout, Oncorhynchus mykiss, and their hybrids

USGS Publications Warehouse

Muhlfeld, C.C.; McMahon, T.E.; Belcer, D.; Kershner, J.L.

2009-01-01

We used radiotelemetry to assess spatial and temporal spawning distributions of native westslope cutthroat trout (Oncorhynchus clarkii lewisi; WCT), introduced rainbow trout (Oncorhynchus mykiss; RBT), and their hybrids in the upper Flathead River system, Montana (USA) and British Columbia (Canada), from 2000 to 2007. Radio-tagged trout (N = 125) moved upriver towards spawning sites as flows increased during spring runoff and spawned in 29 tributaries. WCT migrated greater distances and spawned in headwater streams during peak flows and as flows declined, whereas RBT and RBT hybrids (backcrosses to RBT) spawned earlier during increasing flows and lower in the system. WCT hybrids (backcrosses to WCT) spawned intermediately in time and space to WCT and RBT and RBT hybrids. Both hybrid groups and RBT, however, spawned over time periods that produced temporal overlap with spawning WCT in most years. Our data indicate that hybridization is spreading via long-distance movements of individuals with high amounts of RBT admixture into WCT streams and stepping-stone invasion at small scales by later generation backcrosses. This study provides evidence that hybridization increases the likelihood of reproductive overlap in time and space, promoting extinction by introgression, and that the spread of hybridization is likely to continue if hybrid source populations are not reduced or eliminated.

Abundance and Activity of 16S rRNA, AmoA and NifH Bacterial Genes During Assisted Phytostabilization of Mine Tailings.

PubMed

Nelson, Karis N; Neilson, Julia W; Root, Robert A; Chorover, Jon; Maier, Raina M

2015-01-01

Mine tailings in semiarid regions are highly susceptible to erosion and are sources of dust pollution and potential avenues of human exposure to toxic metals. One constraint to revegetation of tailings by phytostabilization is the absence of microbial communities critical for biogeochemical cycling of plant nutrients. The objective of this study was to evaluate specific genes as in situ indicators of biological soil response during phytoremediation. The abundance and activity of 16S rRNA, nifH, and amoA were monitored during a nine month phytostabilization study using buffalo grass and quailbush grown in compost-amended, metalliferous tailings. The compost amendment provided a greater than 5-log increase in bacterial abundance, and survival of this compost-inoculum was more stable in planted treatments. Despite increased abundance, the activity of the introduced community was low, and significant increases were not detected until six and nine months in quailbush, and unplanted compost and buffalo grass treatments, respectively. In addition, increased abundances of nitrogen-fixation (nifH) and ammonia-oxidizing (amoA) genes were observed in rhizospheres of buffalo grass and quailbush, respectively. Thus, plant establishment facilitated the short term stabilization of introduced bacterial biomass and supported the growth of two key nitrogen-cycling populations in compost-amended tailings.

Behavioural change models for infectious disease transmission: a systematic review (2010–2015)

PubMed Central

2016-01-01

We review behavioural change models (BCMs) for infectious disease transmission in humans. Following the Cochrane collaboration guidelines and the PRISMA statement, our systematic search and selection yielded 178 papers covering the period 2010–2015. We observe an increasing trend in published BCMs, frequently coupled to (re)emergence events, and propose a categorization by distinguishing how information translates into preventive actions. Behaviour is usually captured by introducing information as a dynamic parameter (76/178) or by introducing an economic objective function, either with (26/178) or without (37/178) imitation. Approaches using information thresholds (29/178) and exogenous behaviour formation (16/178) are also popular. We further classify according to disease, prevention measure, transmission model (with 81/178 population, 6/178 metapopulation and 91/178 individual-level models) and the way prevention impacts transmission. We highlight the minority (15%) of studies that use any real-life data for parametrization or validation and note that BCMs increasingly use social media data and generally incorporate multiple sources of information (16/178), multiple types of information (17/178) or both (9/178). We conclude that individual-level models are increasingly used and useful to model behaviour changes. Despite recent advancements, we remain concerned that most models are purely theoretical and lack representative data and a validation process. PMID:28003528

Cost-effectiveness of Chlamydia antibody tests in subfertile women.

PubMed

Fiddelers, A A A; Land, J A; Voss, G; Kessels, A G H; Severens, J L

2005-02-01

For the evaluation of tubal function, Chlamydia antibody testing (CAT) has been introduced as a screening test. We compared six CAT screening strategies (five CAT tests and one combination of tests), with respect to their cost-effectiveness, by using IVF pregnancy rate as outcome measure. A decision analytic model was developed based on a source population of 1715 subfertile women. The model incorporates hysterosalpingography (HSG), laparoscopy and IVF. To calculate IVF pregnancy rates, costs, effects, cost-effectiveness and incremental costs per effect of the six different CAT screening strategies were determined. pELISA Medac turned out to be the most cost-effective CAT screening strategy (15 075 per IVF pregnancy), followed by MIF Anilabsystems (15 108). A combination of tests (pELISA Medac and MIF Anilabsystems; 15 127) did not improve the cost-effectiveness of the single strategies. Sensitivity analyses showed that the results are robust for changes in the baseline values of the model parameters. Only small differences were found between the screening strategies regarding the cost-effectiveness, although pELISA Medac was the most cost-effective strategy. Before introducing a particular CAT test into clinical practice, one should consider the effects and consequences of the entire screening strategy, instead of only the diagnostic accuracy of the test used.

Genetic characterization and phylogeography of the wild boar Sus scrofa introduced into Uruguay

PubMed Central

García, Graciela; Vergara, Julia; Lombardi, Raúl

2011-01-01

The European wild boar Sus scrofa was first introduced into Uruguay, in southern South America during the early decades of the last century. Subsequently, and starting from founder populations, its range spread throughout the country and into the neighbouring Brazilian state Rio Grande do Sul. Due to the subsequent negative impact, it was officially declared a national pest. The main aim in the present study was to provide a more comprehensive scenario of wild boar differentiation in Uruguay, by using mtDNA markers to access the genetic characterization of populations at present undergoing rapid expansion. A high level of haplotype diversity, intermediate levels of nucleotide diversity and considerable population differentiation, were detected among sampled localities throughout major watercourses and catchment dams countrywide. Phylogenetic analysis revealed the existence of two different phylogroups, thereby reflecting two deliberate introduction events forming distantly genetic lineages in local wild boar populations. Our analysis lends support to the hypothesis that the invasive potential of populations emerge from introgressive hybridization with domestic pigs. On taking into account the appreciable differentiation and reduced migration between locales in wild boar populations, management strategies could be effective if each population were to be considered as a single management unit. PMID:21734838

Population dynamics and evaluation of alternative management strategies for nonnative Lake Trout in Priest Lake, Idaho

USGS Publications Warehouse

Ng, Elizabeth L.; Fredericks, Jim P.; Quist, Michael C.

2016-01-01

Lake Trout Salvelinus namaycush have been introduced widely throughout the western USA to enhance recreational fisheries, but high predatory demand can create challenges for management of yield and trophy fisheries alike. Lake Trout were introduced to Priest Lake, Idaho, during the 1920s, but few fishery-independent data are available to guide current or future management actions. We collected fishery-independent data to describe population dynamics and evaluate potential management scenarios using an age-structured population model. Lake Trout in Priest Lake were characterized by fast growth at young ages, which resulted in young age at maturity. However, adult growth rates and body condition were lower than for other Lake Trout populations. High rates of skipped spawning (>50%) were also observed. Model projections indicated that the population was growing (λ = 1.03). Eradication could be achieved by increasing annual mortality to 0.32, approximately twice the current rate. A protected slot length limit could increase population length-structure, but few fish grew fast enough to exit the slot. In contrast, a juvenile removal scenario targeting age-2 to age-5 Lake Trout maintained short-term harvest of trophy-length individuals while reducing overall population abundance.

Research into health, population and social transitions in rural South Africa: Data and methods of the Agincourt Health and Demographic Surveillance System1

PubMed Central

KAHN, KATHLEEN; TOLLMAN, STEPHEN M.; COLLINSON, MARK A.; CLARK, SAMUEL J.; TWINE, RHIAN; CLARK, BENJAMIN D.; SHABANGU, MILDRED; GÓMEZ-OLIVÉ, FRANCESC XAVIER; MOKOENA, OBED; GARENNE, MICHEL L.

2010-01-01

Rationale for study Vital registration is generally lacking in infrastructurally weak areas where health and development problems are most pressing. Health and demographic surveillance is a response to the lack of a valid information base that can provide high-quality longitudinal data on population dynamics, health, and social change to inform policy and practice. Design and measurement procedures Continuous demographic monitoring of an entire geographically defined population involves a multi-round, prospective community study, with annual recording of all vital events (births, deaths, migrations). Status observations and special modules add value to particular research areas. A verbal autopsy is conducted on every death to determine its probable cause. A geographic surveillance system supports spatial analyses, and strengthens field management. Population and sample size considerations Health and demographic surveillance covers the Agincourt sub-district population, sited in rural north-eastern South Africa, of some 70,000 people (nearly a third are Mozambican immigrants) in 21 villages and 11,700 households. Data enumerated are consistent or more detailed when compared with national sources; strategies to improve incomplete data, such as counts of perinatal deaths, have been introduced with positive effect. Basic characteristics A major health and demographic transition was documented over a 12-year period with marked changes in population structure, escalating mortality, declining fertility, and high levels of temporary migration increasing particularly amongst women. A dual burden of infectious and non-communicable disease exists against a background of dramatically progressing HIV/AIDS. Potential and research questions Health and demographic surveillance sites – fundamental to the INDEPTH Network – generate research questions and hypotheses from empirical data, highlight health, social and population priorities, provide cost-effective support for diverse study designs, and track population change and the impact of interventions over time. PMID:17676498

Who Can Afford Health Care? Evaluating the Socio-Economic Conditions and the Ability to Contribute to Health Care in a Post-Conflict Area in DR Congo

PubMed Central

Gerstl, Sibylle; Sauter, Justin; Kasanda, Joseph; Kinzelbach, Alfred

2013-01-01

Introduction The Democratic Republic of the Congo is today one of the poorest countries in the world; the health status of the population ranks among the worst in Sub-Saharan Africa. Public health services charge user fees and drug prices. Since 2008, north-eastern Congo is facing a guerrilla war. Malteser International is assisting with free health care for internally displaced persons as well as the general population. Before the incursion the health system was based on user fees. The aim of this study was to determine the socio-economic conditions of the population and to assess their ability to contribute to health care. Methodology Heads of 552 randomly selected households in 23 clusters in two health zones were interviewed using a standardised questionnaire. Findings The demographic description and socio-economic conditions of the study population were homogenous. Major source of income was agriculture (57%); 47% of the households earned less than US$ 5.5/week. Ninety-two percent of the interviewed households estimated that they would be able to contribute to consultation fees (maximum amount of US$ 0.27) and 79% to the drug prices (maximum amount of US$ 1.10). Six percent opted for free consultations and 19% for free drugs. Conclusions Living conditions were very basic; the estimated income of the study population was low. Almost half of the population perceived their current living situation as fairly good/good. More than 90% of the study population estimated to be able to contribute to consultation fees and 80% to drug prices. As a result Malteser International suggested introducing flat-rates for health care services. Once the project ends, the population will have to pay again for their health service. One solution would be the introduction of a health care financing system with the goal to reach universal coverage to health care. PMID:24204819

Levitation of objects using acoustic energy

NASA Technical Reports Server (NTRS)

Whymark, R. R.

1975-01-01

Activated sound source establishes standing-wave pattern in gap between source and acoustic reflector. Solid or liquid material introduced in region will move to one of the low pressure areas produced at antinodes and remain suspended as long as acoustic signal is present.

Genomic Consequences of Population Decline in the Endangered Florida Scrub-Jay.

PubMed

Chen, Nancy; Cosgrove, Elissa J; Bowman, Reed; Fitzpatrick, John W; Clark, Andrew G

2016-11-07

Understanding the population genetic consequences of declining population size is important for conserving the many species worldwide facing severe decline [1]. Thorough empirical studies on the impacts of population reduction at a genome-wide scale in the wild are scarce because they demand huge field and laboratory investments [1, 2]. Previous studies have demonstrated the importance of gene flow in introducing genetic variation to small populations [3], but few have documented both genetic and fitness consequences of decreased immigration through time in a natural population [4-6]. Here we assess temporal variation in gene flow, inbreeding, and fitness using longitudinal genomic, demographic, and phenotypic data from a long-studied population of federally Threatened Florida scrub-jays (Aphelocoma coerulescens). We exhaustively sampled and genotyped the study population over two decades, providing one of the most detailed longitudinal investigations of genetics in a wild animal population to date. Immigrants were less heterozygous than residents but still introduced genetic variation into our study population. Owing to regional population declines, immigration into the study population declined from 1995-2013, resulting in increased levels of inbreeding and reduced fitness via inbreeding depression, even as the population remained demographically stable. Our results show that, contrary to conventional wisdom, small peripheral populations that already have undergone a genetic bottleneck may play a vital role in preserving genetic diversity of larger and seemingly stable populations. These findings underscore the importance of investing in the persistence of small populations and maintaining population connectivity in conservation of fragmented species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Real payoffs and virtual trading in agent based market models

NASA Astrophysics Data System (ADS)

Ferreira, Fernando F.; Marsili, Matteo

2005-01-01

The -Game was recently introduced as an extension of the Minority Game. In this paper we compare this model with the well know Minority Game and the Majority Game models. Due to the inter-temporal nature of the market payoff, we introduce a two step transaction with single and mixed group of interacting traders. When the population is composed of two different group of -traders, they show an anti-imitative behavior. However, when they interact with minority or majority players the $-population imitates the usual behavior of these players. Finally we discuss how these models contribute to clarify the market mechanism.

Innovative technologies for decentralised water-, wastewater and biowaste management in urban and peri-urban areas.

PubMed

Otterpohl, R; Braun, U; Oldenburg, M

2003-01-01

Avoiding the comingling of water flows coming from different sources and thus obtaining flows with a very low dilution factor is the first and major step key to technical solutions for adequate treatment of household wastewaters. Through their decentral structure and effective recovery of water, energy and fertiliser these systems can be highly cost efficient. Fresh water consumption can be reduced by up to 80% while nutrients can be recovered to a large extent. Source control is also advantageous for hygienic reasons: low volumes are far easier to sanitise. Source separation technology in municipal waste water treatment does often lead decentralised or semicentral systems. The first essential step is the separate collection and treatment of toilet waste in households, which contains almost all pathogens and nutrients. New toilet systems with very low dilution factors, ranging from vacuum- through urine sorting to dry toilets, have been introduced in several projects and proven feasible. New ideas such as the black- and greywater cycle systems are presently under research at the Technical University Hamburg Harburg. Such modular, integrated and small scale systems are only possible through recent advances in membrane technology and, due to their small scale, do have the potential to be installed in densely populated regions. These technologies are options for following the principles of ecological sanitation, to contain, to sanitise and to reuse also in urban areas (EcoSanRes, 2003).

Climate Change Impacts on Environmental and Human Exposure to Mercury in the Arctic

PubMed Central

Sundseth, Kyrre; Pacyna, Jozef M.; Banel, Anna; Pacyna, Elisabeth G.; Rautio, Arja

2015-01-01

This paper reviews information from the literature and the EU ArcRisk project to assess whether climate change results in an increase or decrease in exposure to mercury (Hg) in the Arctic, and if this in turn will impact the risks related to its harmful effects. It presents the state-of-the art of knowledge on atmospheric mercury emissions from anthropogenic sources worldwide, the long-range transport to the Arctic, and it discusses the likely environmental fate and exposure effects on population groups in the Arctic under climate change conditions. The paper also includes information about the likely synergy effects (co-benefits) current and new climate change polices and mitigation options might have on mercury emissions reductions in the future. The review concludes that reductions of mercury emission from anthropogenic sources worldwide would need to be introduced as soon as possible in order to assure lowering the adverse impact of climate change on human health. Scientific information currently available, however, is not in the position to clearly answer whether climate change will increase or decrease the risk of exposure to mercury in the Arctic. New research should therefore be undertaken to model the relationships between climate change and mercury exposure. PMID:25837201

Particle swarm optimization algorithm for optimizing assignment of blood in blood banking system.

PubMed

Olusanya, Micheal O; Arasomwan, Martins A; Adewumi, Aderemi O

2015-01-01

This paper reports the performance of particle swarm optimization (PSO) for the assignment of blood to meet patients' blood transfusion requests for blood transfusion. While the drive for blood donation lingers, there is need for effective and efficient management of available blood in blood banking systems. Moreover, inherent danger of transfusing wrong blood types to patients, unnecessary importation of blood units from external sources, and wastage of blood products due to nonusage necessitate the development of mathematical models and techniques for effective handling of blood distribution among available blood types in order to minimize wastages and importation from external sources. This gives rise to the blood assignment problem (BAP) introduced recently in literature. We propose a queue and multiple knapsack models with PSO-based solution to address this challenge. Simulation is based on sets of randomly generated data that mimic real-world population distribution of blood types. Results obtained show the efficiency of the proposed algorithm for BAP with no blood units wasted and very low importation, where necessary, from outside the blood bank. The result therefore can serve as a benchmark and basis for decision support tools for real-life deployment.

Climate change impacts on environmental and human exposure to mercury in the arctic.

PubMed

Sundseth, Kyrre; Pacyna, Jozef M; Banel, Anna; Pacyna, Elisabeth G; Rautio, Arja

2015-03-31

This paper reviews information from the literature and the EU ArcRisk project to assess whether climate change results in an increase or decrease in exposure to mercury (Hg) in the Arctic, and if this in turn will impact the risks related to its harmful effects. It presents the state-of-the art of knowledge on atmospheric mercury emissions from anthropogenic sources worldwide, the long-range transport to the Arctic, and it discusses the likely environmental fate and exposure effects on population groups in the Arctic under climate change conditions. The paper also includes information about the likely synergy effects (co-benefits) current and new climate change polices and mitigation options might have on mercury emissions reductions in the future. The review concludes that reductions of mercury emission from anthropogenic sources worldwide would need to be introduced as soon as possible in order to assure lowering the adverse impact of climate change on human health. Scientific information currently available, however, is not in the position to clearly answer whether climate change will increase or decrease the risk of exposure to mercury in the Arctic. New research should therefore be undertaken to model the relationships between climate change and mercury exposure.

Old world versus new world: life-history alterations in a successful invader introduced across Europe.

PubMed

Fox, Michael G; Copp, Gordon H

2014-02-01

We examined differences in pumpkinseed (Lepomis gibbosus) life-history traits between native North American and introduced European populations, and tested three life-history predictions related to the effect of temperature, growth, waterbody size, and the presence/absence of predators on native and non-native populations. Pumpkinseed populations exhibit more 'opportunistic' traits (earlier maturity, smaller size at maturity, and higher reproductive allocation) in their introduced European range than those in their native range. Predictions of life-history traits were improved when indicators of juvenile growth rate (mean length at age 2), waterbody size (surface area), and thermal regime (air temperature degree-days above 10 °C) were incorporated into models along with continental location, but European pumpkinseed populations exhibit more opportunistic life-history traits than North American populations even when these factors are accounted for. Native pumpkinseed in waterbodies containing piscivores mature later and at a larger size, and have lower gonadosomatic indices than those in waterbodies lacking piscivores, whereas there is no significant difference in the same three life-history traits between European waterbodies containing or lacking piscivores. Because congeneric competitors of the pumpkinseed are absent from Europe, the apparent absence of a predator life-history effect there could also be due to the absence of the major sunfish competitors. In either case, the evolution and maintenance of more opportunistic traits in European pumpkinseed can likely be attributed to enemy release, and this may explain the successful establishment and spread of pumpkinseed in many parts of Europe.

Genome-wide DNA methylation alterations of Alternanthera philoxeroides in natural and manipulated habitats: implications for epigenetic regulation of rapid responses to environmental fluctuation and phenotypic variation.

PubMed

Gao, Lexuan; Geng, Yupeng; Li, Bo; Chen, Jiakuan; Yang, Ji

2010-11-01

Alternanthera philoxeroides (alligator weed) is an invasive weed that can colonize both aquatic and terrestrial habitats. Individuals growing in different habitats exhibit extensive phenotypic variation but little genetic differentiation in its introduced range. The mechanisms underpinning the wide range of phenotypic variation and rapid adaptation to novel and changing environments remain uncharacterized. In this study, we examined the epigenetic variation and its correlation with phenotypic variation in plants exposed to natural and manipulated environmental variability. Genome-wide methylation profiling using methylation-sensitive amplified fragment length polymorphism (MSAP) revealed considerable DNA methylation polymorphisms within and between natural populations. Plants of different source populations not only underwent significant morphological changes in common garden environments, but also underwent a genome-wide epigenetic reprogramming in response to different treatments. Methylation alterations associated with response to different water availability were detected in 78.2% (169/216) of common garden induced polymorphic sites, demonstrating the environmental sensitivity and flexibility of the epigenetic regulatory system. These data provide evidence of the correlation between epigenetic reprogramming and the reversible phenotypic response of alligator weed to particular environmental factors. © 2010 Blackwell Publishing Ltd.

Globular clusters in high-redshift dwarf galaxies: a case study from the Local Group

NASA Astrophysics Data System (ADS)

Zick, Tom O.; Weisz, Daniel R.; Boylan-Kolchin, Michael

2018-06-01

We present the reconstructed evolution of rest-frame ultraviolet (UV) luminosities of the most massive Milky Way dwarf spheroidal satellite galaxy, Fornax, and its five globular clusters (GCs) across redshift, based on analysis of the stellar fossil record and stellar population synthesis modelling. We find that (1) Fornax's (proto-)GCs can generate 10-100 times more UV flux than the field population, despite comprising <˜{5} per cent of the stellar mass at the relevant redshifts; (2) due to their respective surface brightnesses, it is more likely that faint, compact sources in the Hubble Frontier Fields (HFFs) are GCs hosted by faint galaxies, than faint galaxies themselves. This may significantly complicate the construction of a galaxy UV luminosity function at z > 3. (3) GC formation can introduce order-of-magnitude errors in abundance matching. We also find that some compact HFF objects are consistent with the reconstructed properties of Fornax's GCs at the same redshifts (e.g. surface brightness, star formation rate), suggesting we may have already detected proto-GCs in the early Universe. Finally, we discuss the prospects for improving the connections between local GCs and proto-GCs detected in the early Universe.

A genetic survey of Salvinia minima in the southern United States

USGS Publications Warehouse

Madeira, Paul T.; Jacono, C.C.; Tipping, Phil; Van, Thai K.; Center, Ted D.

2003-01-01

The genetic relationships among 68 samples of Salvinia minima (Salviniaceae) were investigated using RAPD analysis. Neighbor joining, principle components, and AMOVA analyses were used to detect differences among geographically referenced samples within and outside of Florida. Genetic distances (Nei and Li) range up to 0.48, although most are under 0.30, still relatively high levels for an introduced, clonally reproducing plant. Despite the diversity AMOVA analysis yielded no indication that the Florida plants, as a group, were significantly different from the plants sampled elsewhere in its adventive, North American range. A single, genetically dissimilar population probably exists in the recent (1998) horticultural introduction to Mississippi. When the samples were grouped into 10 regional (but artificial) units and analyzed using AMOVA the between region variance was only 7.7%. Genetic similarity among these regions may indicate introduction and dispersal from common sources. The reduced aggressiveness of Florida populations (compared to other states) may be due to herbivory. The weevil Cyrtobagous salviniae, a selective feeder, is found in Florida but not other states. The genetic similarity also suggests that there are no obvious genetic obstacles to the establishment or efficacy of C. salviniae as a biological control agent on S. minima outside of Florida.

Introducing Synchrotrons Into the Classroom

ScienceCinema

Bloch, Ashley; Lanzirotti, Tony

2018-06-08

Brookhaven's Introducing Synchrotrons Into the Classroom (InSynC) program gives teachers and their students access to the National Synchrotron Light Source through a competitive proposal process. The first batch of InSynC participants included a group of students from Islip Middle School, who used the massive machine to study the effectiveness of different what filters.

Vegetation component of geothermal EIS studies: Introduced plants, ecosystem stability, and geothermal development

NASA Astrophysics Data System (ADS)

1994-10-01

This paper contributes new information about the impacts from introduced plant invasions on the native Hawaiian vegetation as consequences of land disturbance and geothermal development activities. In this regard, most geothermal development is expected to act as another recurring source of physical disturbance which favors the spread and maintenance of introduced organisms throughout the region. Where geothermal exploration and development activities extend beyond existing agricultural and residential development, they will become the initial or sole source of disturbance to the naturalized vegetation of the area. Kilauea has a unique ecosystem adapted to the dynamics of a volcanically active landscape. The characteristics of this ecosystem need to be realized in order to understand the major threats to the ecosystem and to evaluate the effects of and mitigation for geothermal development in Puna. The native Puna vegetation is well adapted to disturbances associated with volcanic eruption, but it is ill-adapted to compete with alien plant species in secondary disturbances produced by human activities. Introduced plant and animal species have become a major threat to the continued presence of the native biota in the Puna region.

An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

DOE PAGES

Van Berkel, Gary J.; Kertesz, Vilmos

2015-08-25

RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creatingmore » a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.« less

Using Asymptotic Results to Obtain a Confidence Interval for the Population Median

ERIC Educational Resources Information Center

Jamshidian, M.; Khatoonabadi, M.

2007-01-01

Almost all introductory and intermediate level statistics textbooks include the topic of confidence interval for the population mean. Almost all these texts introduce the median as a robust measure of central tendency. Only a few of these books, however, cover inference on the population median and in particular confidence interval for the median.…

Understanding Social Integration and Student Involvement as Factors of Self-Reported Gains for African American Undergraduate Women

ERIC Educational Resources Information Center

Miller, Edna Jones

2012-01-01

Diversity of student populations within higher education has considerably increased, particularly for women and minority populations, which is indicative of greater access to education toward a college degree. However, increased diversity of student populations has introduced a new set of challenges for higher education administrators in that it…

Integration of Population Education in APPEAL. Volume Two: Population Education in Universal Primary Education.

ERIC Educational Resources Information Center

United Nations Educational, Scientific and Cultural Organization, Bangkok (Thailand). Principal Regional Office for Asia and the Pacific.

These lesson plans are the result of two regional workshops sponsored by UNESCO in Indonesia in 1989 and Pakistan in 1991. The workshops focused on the need to introduce population education core messages in the Asia-Pacific Programme of Education for All (APPEAL). These prototypes of exemplar instructional materials for primary education,…

Site-specific temporal and spatial validation of a generic plant pest forecast system with observations of Bactrocera dorsalis (oriental fruit fly).

USDA-ARS?s Scientific Manuscript database

This study introduces a simple generic model, the Generic Pest Forecast System (GPFS), for simulatingthe relative populations of non-indigenousarthropod pests in space and time. The model was designed to calculate the population index or relative population using hourly weather dataas influenced by...

Can lowland dry forests represent a refuge from avian malaria for native Hawaiian birds?

USGS Publications Warehouse

Tucker-Mohl, Katherine; Hart, Patrick; Atkinson, Carter T.

2010-01-01

Hawaii's native birds have become increasingly threatened over the past century. Introduced mosquito borne diseases such as avian malaria may be responsible for the near absence of endemic Hawaiian forest birds in low-elevation habitats. The recent recognition that some native Hawaiian forest birds may be repopulating moist lowland habitats as a result of evolved resistance to this disease has increased the conservation value of these areas. Here, we investigate whether remnant low elevation dry forests on Hawaii Island provide natural 'refuges' from mosquito-transmitted malaria by nature of their low rainfall and absence of suitable natural sources of water for mosquito breeding. Unlike lowland wet forests where high rates of disease transmission may be selecting for disease resistance, lowland dry forests may provide some refuge for native forest birds without natural resistance to malaria. We mistnetted forest birds in two lowland dry forests and tested all native birds by microscopy and serology for avian malaria caused by the Plasmodium relictum parasite. We also conducted surveys for standing water and mosquito larvae. Overall prevalence of infections with Plasmodium relictum in the Hawaii Amakihi Hemignathus virens virens was 15%. Most infected birds had lowlevel parasitemias, suggesting chronic infections. Although avian malaria is present in these lowland dry forest Amakihi populations, infection rates are significantly lower than in wet forest populations at similar elevations. Sources of breeding mosquitoes in these forests appeared to be largely anthropogenic; thus, there is potential to manage dry forests as mosquito-free habitat for Hawaii Amakihi and other Hawaiian forest birds.

History of research on modelling gypsy moth population ecology

Treesearch

J. J. Colbert

1991-01-01

History of research to develop models of gypsy moth population dynamics and some related studies are described. Empirical regression-based models are reviewed, and then the more comprehensive process models are discussed. Current model- related research efforts are introduced.

Introducing the World Population Crises to Secondary Social Studies Classes: An Inquiry-Oriented Instructional Strategy

ERIC Educational Resources Information Center

Anderson, Randall C.

1970-01-01

The author contends that students must be alerted to the dangers of overpopulation of the world and to the methods that exist to control population growth. He suggests topics for student inquiry. (CK)

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

40 CFR 421.326 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Uranium Subcategory... wastewater pollutants in secondary uranium process wastewater introduced into a POTW shall not exceed the following values: (a) Refinery sump filtrate. PSNS for the Secondary Uranium Subcategory Pollutant or...

40 CFR 421.326 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Uranium Subcategory... wastewater pollutants in secondary uranium process wastewater introduced into a POTW shall not exceed the following values: (a) Refinery sump filtrate. PSNS for the Secondary Uranium Subcategory Pollutant or...

40 CFR 421.326 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Uranium Subcategory... wastewater pollutants in secondary uranium process wastewater introduced into a POTW shall not exceed the following values: (a) Refinery sump filtrate. PSNS for the Secondary Uranium Subcategory Pollutant or...

Overview of Microbial Source Tracking Methods Targeting Human Fecal Pollution Sources

EPA Science Inventory

Exposure to human fecal waste can be a public health risk dueto the presence of human pathogens. Human fecal pollutioncan be introduced into water resources from damagedsewer lines, faulty septic systems, combined sewer overflows,illicit dumping activities, and even recreational ...

APPLICATION OF PROTEOMIC METHODS TO ARSENIC EXPOSURE RESEARCH

EPA Science Inventory

Arsenic, an environmental contaminant, is introduced to drinking water through the leaching of soil and the result of anthropogenic sources such as industrial effluents and combustion of fossil fuels. It also occurs naturally in ground water sources in some geographic areas. Chro...

The role of local populations within a landscape context: Defining and classifying sources and sinks

USGS Publications Warehouse

Runge, J.P.; Runge, M.C.; Nichols, J.D.

2006-01-01

The interaction of local populations has been the focus of an increasing number of studies in the past 30 years. The study of source-sink dynamics has especially generated much interest. Many of the criteria used to distinguish sources and sinks incorporate the process of apparent survival (i.e., the combined probability of true survival and site fidelity) but not emigration. These criteria implicitly treat emigration as mortality, thus biasing the classification of sources and sinks in a manner that could lead to flawed habitat management. Some of the same criteria require rather restrictive assumptions about population equilibrium that, when violated, can also generate misleading inference. Here, we expand on a criterion (denoted ?contribution? or Cr) that incorporates successful emigration in differentiating sources and sinks and that makes no restrictive assumptions about dispersal or equilibrium processes in populations of interest. The metric Cr is rooted in the theory of matrix population models, yet it also contains clearly specified parameters that have been estimated in previous empirical research. We suggest that estimates of emigration are important for delineating sources and sinks and, more generally, for evaluating how local populations interact to generate overall system dynamics. This suggestion has direct implications for issues such as species conservation and habitat management.

Review of water footprint components of grain

NASA Astrophysics Data System (ADS)

Ahmad, Wan Amiza Amneera Wan; Meriam Nik Sulaiman, Nik; Zalina Mahmood, Noor

2017-06-01

Burgeoning global population, economic development, agriculture and prevailing climate pattern are among aspects contributed to water scarcity. In low and middle income countries, agriculture takes the highest share among water user sector. Demand for grain is widespread all over the globe. Hence, this study review published papers regarding quantification of water footprint of grain. Review shows there are various methods in quantifying water footprint. In ascertaining water footprint, three (green, blue, grey) or two (green, blue) components of water footprint involved. However, there was a study introduced new term in evaluating water footprint, white water footprint. The vulnerability of varying methods is difficulty in conducting comparative among water footprint. Salient source in contributing high water footprint also varies. In some studies, green water footprint play major role. Conversely, few studies found out blue water footprint most contributing component in water footprint. This fluctuate pattern influenced by various aspects, namely, regional climatic characteristics, crop yield and crop types.

Teaching transcultural nursing through literature.

PubMed

Halloran, Laurel

2009-09-01

One of the biggest challenges in nursing education is to develop culturally sensitive graduates. Although theory and lecture are appropriate to introduce cultural issues, the application of those skills is limited by the kinds of clinical experiences and patient populations students may treat. Literary works are a rich source of information for nursing. This assignment was created to sensitize the students to the influence of cultural diversity. Students were assigned to read one novel from an approved list and answer the questions posed on the Cultural Discovery worksheet. The only direction that was given regarding novel selection was that the novel had to represent a culture other than the student's own. The focus was to expose students to a different culture. Classroom discussion, based on worksheet answers, followed. The assignment's good, bad, and ugly outcomes are discussed. Suggestions for adaptation of this assignment to an online format are also provided.

Incorporating extrinsic noise into the stochastic simulation of biochemical reactions: A comparison of approaches

NASA Astrophysics Data System (ADS)

Thanh, Vo Hong; Marchetti, Luca; Reali, Federico; Priami, Corrado

2018-02-01

The stochastic simulation algorithm (SSA) has been widely used for simulating biochemical reaction networks. SSA is able to capture the inherently intrinsic noise of the biological system, which is due to the discreteness of species population and to the randomness of their reciprocal interactions. However, SSA does not consider other sources of heterogeneity in biochemical reaction systems, which are referred to as extrinsic noise. Here, we extend two simulation approaches, namely, the integration-based method and the rejection-based method, to take extrinsic noise into account by allowing the reaction propensities to vary in time and state dependent manner. For both methods, new efficient implementations are introduced and their efficiency and applicability to biological models are investigated. Our numerical results suggest that the rejection-based method performs better than the integration-based method when the extrinsic noise is considered.

Observing the Anthropocene from Space: Challenges and Needs

NASA Astrophysics Data System (ADS)

Burrows, John

2016-07-01

The rapid growth of human population since the industrial revolution has been coupled with a much increased standard of living and bountiful production of food. The dominant energy source sustaining this development has been fossil fuel combustion. However this has resulted in pollution which now spans all scales. There have significant impacts on air quality, water quality, stratospheric ozone and climate. The impacts can sudden and large and also slowly accumulate over time in the long term. The first decades of the space age resulted in pioneering efforts to establish adequate measurement capability. This process is continuing to evolve. Over the past two decades there have been a number of efforts to define the contribution and needs for a space segment which can separate anthropogenic form natural changes in the earth system. This talk introduces this topic of the use of the space segment to deconvolve change from anthropogenic activity and natural phenomena.

Climate change alters diffusion of forest pest: A model study

NASA Astrophysics Data System (ADS)

Jo, Woo Seong; Kim, Hwang-Yong; Kim, Beom Jun

2017-01-01

Population dynamics with spatial information is applied to understand the spread of pests. We introduce a model describing how pests spread in discrete space. The number of pest descendants at each site is controlled by local information such as temperature, precipitation, and the density of pine trees. Our simulation leads to a pest spreading pattern comparable to the real data for pine needle gall midge in the past. We also simulate the model in two different climate conditions based on two different representative concentration pathways scenarios for the future. We observe that after an initial stage of a slow spread of pests, a sudden change in the spreading speed occurs, which is soon followed by a large-scale outbreak. We found that a future climate change causes the outbreak point to occur earlier and that the detailed spatio-temporal pattern of the spread depends on the source position from which the initial pest infection starts.

Challenges towards Economic Fuel Generation from Renewable Electricity: The Need for Efficient Electro-Catalysis.

PubMed

Formal, Florian Le; Bourée, Wiktor S; Prévot, Mathieu S; Sivula, Kevin

2015-01-01

Utilizing renewable sources of energy is very attractive to provide the growing population on earth in the future but demands the development of efficient storage to mitigate their intermittent nature. Chemical storage, with energy stored in the bonds of chemical compounds such as hydrogen or carbon-containing molecules, is promising as these energy vectors can be reserved and transported easily. In this review, we aim to present the advantages and drawbacks of the main water electrolysis technologies available today: alkaline and PEM electrolysis. The choice of electrode materials for utilization in very basic and very acid conditions is discussed, with specific focus on anodes for the oxygen evolution reaction, considered as the most demanding and energy consuming reaction in an electrolyzer. State-of-the-art performance of materials academically developed for two alternative technologies: electrolysis in neutral or seawater, and the direct electrochemical conversion from solar to hydrogen are also introduced.

Methods to Manipulate and Monitor Wnt Signaling in Human Pluripotent Stem Cells.

PubMed

Huggins, Ian J; Brafman, David; Willert, Karl

2016-01-01

Human pluripotent stem cells (hPSCs) may revolutionize medical practice by providing: (a) a renewable source of cells for tissue replacement therapies, (b) a powerful system to model human diseases in a dish, and (c) a platform for examining efficacy and safety of novel drugs. Furthermore, these cells offer a unique opportunity to study early human development in vitro, in particular, the process by which a seemingly uniform cell population interacts to give rise to the three main embryonic lineages: ectoderm, endoderm. and mesoderm. This process of lineage allocation is regulated by a number of inductive signals that are mediated by growth factors, including FGF, TGFβ, and Wnt. In this book chapter, we introduce a set of tools, methods, and protocols to specifically manipulate the Wnt signaling pathway with the intention of altering the cell fate outcome of hPSCs.

CrowdHEALTH: Holistic Health Records and Big Data Analytics for Health Policy Making and Personalized Health.

PubMed

Kyriazis, Dimosthenis; Autexier, Serge; Brondino, Iván; Boniface, Michael; Donat, Lucas; Engen, Vegard; Fernandez, Rafael; Jimenez-Peris, Ricardo; Jordan, Blanca; Jurak, Gregor; Kiourtis, Athanasios; Kosmidis, Thanos; Lustrek, Mitja; Maglogiannis, Ilias; Mantas, John; Martinez, Antonio; Mavrogiorgou, Argyro; Menychtas, Andreas; Montandon, Lydia; Nechifor, Cosmin-Septimiu; Nifakos, Sokratis; Papageorgiou, Alexandra; Patino-Martinez, Marta; Perez, Manuel; Plagianakos, Vassilis; Stanimirovic, Dalibor; Starc, Gregor; Tomson, Tanja; Torelli, Francesco; Traver-Salcedo, Vicente; Vassilacopoulos, George; Wajid, Usman

2017-01-01

Today's rich digital information environment is characterized by the multitude of data sources providing information that has not yet reached its full potential in eHealth. The aim of the presented approach, namely CrowdHEALTH, is to introduce a new paradigm of Holistic Health Records (HHRs) that include all health determinants. HHRs are transformed into HHRs clusters capturing the clinical, social and human context of population segments and as a result collective knowledge for different factors. The proposed approach also seamlessly integrates big data technologies across the complete data path, providing of Data as a Service (DaaS) to the health ecosystem stakeholders, as well as to policy makers towards a "health in all policies" approach. Cross-domain co-creation of policies is feasible through a rich toolkit, being provided on top of the DaaS, incorporating mechanisms for causal and risk analysis, and for the compilation of predictions.

On X-Ray Variability in Seyfert Galaxies

NASA Technical Reports Server (NTRS)

Turner, T. J.; George, I. M.; Nandra, K.; Turcan, D.

1999-01-01

This paper presents a quantification of the X-ray variability amplitude for 79 ASCA observations of 36 Seyfert 1 galaxies. We find that consideration of sources with the narrowest permitted lines in the optical band introduces scatter into the established correlation between X-ray variability and nuclear luminosity. Consideration of the X-ray spectral index and variability properties together shows distinct groupings in parameter space for broad and narrow-line Seyfert 1 galaxies, confirming previous studies. A strong correlation is found between hard X-ray variability and FWHM Hbeta. A range of nuclear mass and accretion rate across the Seyfert population can explain the differences observed in X-ray and optical properties. An attractive alternative model, which does not depend on any systematic difference in central mass, is that the circumnuclear gas of NLSy1s is different to BLSy1s in temperature, optical depth, density or geometry.

High levels of insecticide resistance in introduced horn fly (Diptera: Muscidae) populations and implications for management

USDA-ARS?s Scientific Manuscript database

The horn fly, Haematobia irritans (L.) (Diptera: Muscidae) was introduced to Chile early in the 1990s. Since their introduction, farmers have controlled this pest almost exclusively with insecticides. In order to understand the consequences of different control strategies on the development of insec...

Distinguishing Continuous and Discrete Approaches to Multilevel Mixture IRT Models: A Model Comparison Perspective

ERIC Educational Resources Information Center

Zhu, Xiaoshu

2013-01-01

The current study introduced a general modeling framework, multilevel mixture IRT (MMIRT) which detects and describes characteristics of population heterogeneity, while accommodating the hierarchical data structure. In addition to introducing both continuous and discrete approaches to MMIRT, the main focus of the current study was to distinguish…

New strategies for weed prevention

Treesearch

Randy G. Westbrooks; Lee Otteni; Robert E. Eplee

1998-01-01

Over the past several thousand years, Man has moved many plant species far beyond their historical native range. Many introduced plants that have become established outside of cultivation are benign (so far). However, some introduced species with free-living populations pose a threat to the biodiversity of natural areas and/or diminish the production capacity of...

On the inclusion of mass source terms in a single-relaxation-time lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Aursjø, Olav; Jettestuen, Espen; Vinningland, Jan Ludvig; Hiorth, Aksel

2018-05-01

We present a lattice Boltzmann algorithm for incorporating a mass source in a fluid flow system. The proposed mass source/sink term, included in the lattice Boltzmann equation, maintains the Galilean invariance and the accuracy of the overall method, while introducing a mass source/sink term in the fluid dynamical equations. The method can, for instance, be used to inject or withdraw fluid from any preferred lattice node in a system. This suggests that injection and withdrawal of fluid does not have to be introduced through cumbersome, and sometimes less accurate, boundary conditions. The method also suggests that, through a chosen equation of state relating mass density to pressure, the proposed mass source term will render it possible to set a preferred pressure at any lattice node in a system. We demonstrate how this model handles injection and withdrawal of a fluid. And we show how it can be used to incorporate pressure boundaries. The accuracy of the algorithm is identified through a Chapman-Enskog expansion of the model and supported by the numerical simulations.

A novel semiconductor-based, fully incoherent amplified spontaneous emission light source for ghost imaging

PubMed Central

Hartmann, Sébastien; Elsäßer, Wolfgang

2017-01-01

Initially, ghost imaging (GI) was demonstrated with entangled light from parametric down conversion. Later, classical light sources were introduced with the development of thermal light GI concepts. State-of-the-art classical GI light sources rely either on complex combinations of coherent light with spatially randomizing optical elements or on incoherent lamps with monochromating optics, however suffering strong losses of efficiency and directionality. Here, a broad-area superluminescent diode is proposed as a new light source for classical ghost imaging. The coherence behavior of this spectrally broadband emitting opto-electronic light source is investigated in detail. An interferometric two-photon detection technique is exploited in order to resolve the ultra-short correlation timescales. We thereby quantify the coherence time, the photon statistics as well as the number of spatial modes unveiling a complete incoherent light behavior. With a one-dimensional proof-of-principle GI experiment, we introduce these compact emitters to the field which could be beneficial for high-speed GI systems as well as for long range GI sensing in future applications. PMID:28150737

Elevated blood-lead levels among children living in the rural Philippines.

PubMed

Riddell, Travis J; Solon, Orville; Quimbo, Stella A; Tan, Cheryl May C; Butrick, Elizabeth; Peabody, John W

2007-09-01

Generally, lead poisoning is not considered a significant environmental hazard for children in rural areas of developing countries. With a prospectively designed policy experiment, the research community and the government are conducting a broad-based investigation to introduce and evaluate the impact of health policy reforms on children in a rural area of the Philippines - the Quality Improvement Demonstration Study (QIDS). As part of this study, we researched lead exposure in children under the age of five. We sampled a population of children from the Visayas region in the central Philippines, covering approximately one third of the country's geographical area. From December 2003 to September 2004, the survey collected blood lead levels (BLL) together with demographic, socioeconomic and child health data points. Supplemental field-testing among a sub-sample of the most exposed children assessed the sources of environmental lead exposure. Among children in this study, 21% (601 of 2861 children) had BLL greater than 10 microg/dl. BLL were associated independently with age, haemoglobin concentration, water source, roofing material, expenditures and history of breastfeeding. A follow-up assessment of possible environmental exposures among the sub-sample of children with elevated BLL revealed no single or predominant exposure source. Instead, there appear to be multiple potential sources, such as fossil-fuel combustion, lead paint (in or around 38% of homes) and household items. Elevated BLL are common among children in the Visayas, and may signify an under-recognized threat to children living in rural areas of other developing nations. This setting has varied environmental sources of lead. Observed correlates of BLL may be of clinical, environmental and public health utility to identify and mitigate the consequences of lead toxicity.

An experimental test of the EICA hypothesis in multiple ranges: invasive populations outperform those from the native range independent of insect herbivore suppression

PubMed Central

DeWalt, Saara J.; Zou, Jianwen; Rogers, William E.

2017-01-01

Abstract The success of invasive plants may reflect environmental differences in their native and introduced ranges including both abiotic and biotic conditions, such as release from aboveground herbivory. However, in response to these novel conditions, plants from invasive populations may have higher growth rates and lower defence levels compared with those in the native range. This may contribute to their success in the introduced range but perhaps not in the native range. Here, we grew 1000 Triadica sebifera plants from 14 native and introduced populations in seven common gardens with unmanaged background vegetation for three growing seasons in three geographic venues that varied in T. sebifera status and insect herbivore communities: Texas—T. sebifera is invasive, low levels of generalist herbivory; Hawaii—T. sebifera introduced but not invasive, high levels of generalist herbivory from exotic herbivores; China—native range, both generalist and specialist herbivores. We suppressed aboveground insects with insecticide on half the plants. Aboveground damage in the first growing season was lowest in Texas and insecticide sprays reduced damage in China. At the end of the first growing season, plants were tallest on an average in China and shortest in Hawaii. However, height in later years and mass were the highest on average in Texas and the lowest in Hawaii. However, there was large variation in damage and plant performance among gardens within venues. Our results suggest that more rapid aboveground growth rates contribute to T. sebifera’s success in both the invasive and native ranges independent of aboveground herbivory. However, strong variation among sites indicates that T. sebifera plants from invasive populations only have a strong advantage in a subset of sites in Texas. PMID:28039113

An experimental test of the EICA Hypothesis in multiple ranges: invasive populations outperform those from the native range independent of insect herbivore suppression.

PubMed

Siemann, Evan; DeWalt, Saara J; Zou, Jianwen; Rogers, William E

2016-12-30

The success of invasive plants may reflect environmental differences in their native and introduced ranges including both abiotic and biotic conditions, such as release from aboveground herbivory. However, in response to these novel conditions, plants from invasive populations may have higher growth rates and lower defense levels compared to those in the native range. This may contribute to their success in the introduced range but perhaps not in the native range. Here, we grew 1000 Triadica sebifera plants from 14 native and introduced populations in seven common gardens with unmanaged background vegetation for three growing seasons in three geographic venues that varied in T. sebifera status and insect herbivore communities: Texas -T. sebifera is invasive, low levels of generalist herbivory; Hawaii - T. sebifera introduced but not invasive, high levels of generalist herbivory from exotic herbivores; China - native range, both generalist and specialist herbivores. We suppressed aboveground insects with insecticide on half the plants. Aboveground damage in the first growing season was lowest in Texas and insecticide sprays reduced damage in China. At the end of the first growing season, plants were tallest on average in China and shortest in Hawaii. However, height in later years and mass were highest on average in Texas and lowest in Hawaii. However, there was large variation in damage and plant performance among gardens within venues. Our results suggest that more rapid aboveground growth rates contribute to T. sebifera's success in both the invasive and native ranges independent of aboveground herbivory. However, strong variation among sites indicates that T. sebifera plants from invasive populations only have a strong advantage in a subset of sites in Texas. Published by Oxford University Press on behalf of the Annals of Botany Company.

Iron and Prochlorococcus

DTIC Science & Technology

2009-06-01

greatly influenced by the sources of iron to the marine environment, which include riverine input, hydrothermal upwelling, and atmospheric...deposition (Jickells et al, 2005). While the amount of iron introduced to the oceans from riverine and hydrothermal sources is high, precipitation occurs...rapidly in both cases and removes iron from seawater, minimizing the impact of hydrothermal and riverine sources on the concentration of iron in the

Green Power Grids: How Energy from Renewable Sources Affects Networks and Markets

PubMed Central

Mureddu, Mario; Caldarelli, Guido; Chessa, Alessandro; Scala, Antonio; Damiano, Alfonso

2015-01-01

The increasing attention to environmental issues is forcing the implementation of novel energy models based on renewable sources. This is fundamentally changing the configuration of energy management and is introducing new problems that are only partly understood. In particular, renewable energies introduce fluctuations which cause an increased request for conventional energy sources to balance energy requests at short notice. In order to develop an effective usage of low-carbon sources, such fluctuations must be understood and tamed. In this paper we present a microscopic model for the description and for the forecast of short time fluctuations related to renewable sources in order to estimate their effects on the electricity market. To account for the inter-dependencies in the energy market and the physical power dispatch network, we use a statistical mechanics approach to sample stochastic perturbations in the power system and an agent based approach for the prediction of the market players’ behavior. Our model is data-driven; it builds on one-day-ahead real market transactions in order to train agents’ behaviour and allows us to deduce the market share of different energy sources. We benchmarked our approach on the Italian market, finding a good accordance with real data. PMID:26335705

Green Power Grids: How Energy from Renewable Sources Affects Networks and Markets.

PubMed

Mureddu, Mario; Caldarelli, Guido; Chessa, Alessandro; Scala, Antonio; Damiano, Alfonso

2015-01-01

The increasing attention to environmental issues is forcing the implementation of novel energy models based on renewable sources. This is fundamentally changing the configuration of energy management and is introducing new problems that are only partly understood. In particular, renewable energies introduce fluctuations which cause an increased request for conventional energy sources to balance energy requests at short notice. In order to develop an effective usage of low-carbon sources, such fluctuations must be understood and tamed. In this paper we present a microscopic model for the description and for the forecast of short time fluctuations related to renewable sources in order to estimate their effects on the electricity market. To account for the inter-dependencies in the energy market and the physical power dispatch network, we use a statistical mechanics approach to sample stochastic perturbations in the power system and an agent based approach for the prediction of the market players' behavior. Our model is data-driven; it builds on one-day-ahead real market transactions in order to train agents' behaviour and allows us to deduce the market share of different energy sources. We benchmarked our approach on the Italian market, finding a good accordance with real data.

Plastic waste in the marine environment: A review of sources, occurrence and effects.

PubMed

Li, W C; Tse, H F; Fok, L

2016-10-01

This review article summarises the sources, occurrence, fate and effects of plastic waste in the marine environment. Due to its resistance to degradation, most plastic debris will persist in the environment for centuries and may be transported far from its source, including great distances out to sea. Land- and ocean-based sources are the major sources of plastic entering the environment, with domestic, industrial and fishing activities being the most important contributors. Ocean gyres are particular hotspots of plastic waste accumulation. Both macroplastics and microplastics pose a risk to organisms in the natural environment, for example, through ingestion or entanglement in the plastic. Many studies have investigated the potential uptake of hydrophobic contaminants, which can then bioaccumulate in the food chain, from plastic waste by organisms. To address the issue of plastic pollution in the marine environment, governments should first play an active role in addressing the issue of plastic waste by introducing legislation to control the sources of plastic debris and the use of plastic additives. In addition, plastics industries should take responsibility for the end-of-life of their products by introducing plastic recycling or upgrading programmes. Copyright © 2016 Elsevier B.V. All rights reserved.

Acquired and introduced macroparasites of the invasive Cuban treefrog, Osteopilus septentrionalis

PubMed Central

Ortega, Nicole; Price, Wayne; Campbell, Todd; Rohr, Jason

2015-01-01

Because shifts in host–parasite relationships can alter host populations, attention should be given to the parasites that introduced species take with them or acquire in their introduced range. The Cuban treefrog, Osteopilus septentrionalis, is a successful invasive species in Florida with its parasites in the native range being well-documented, but there is a void in the literature regarding what parasites were lost or introduced in its expansion. We necropsied 330 O. septentrionalis from Tampa, FL and compared their macroparasites to those of O. septentrionalis in their native range and to the parasites of anurans native to the Tampa, FL area to determine the species O. septentrionalis likely introduced or acquired in Florida. At least nine parasite species (Aplectana sp., Oswaldocruzia lenteixeirai, Cylindrotaenia americana, Physaloptera sp., Rhabdias sp., Centrorhynchus sp., unidentified trematode metacercariae, unidentified larval acuariids, and unidentified pentastomids) were isolated. We found no differences in parasite communities of adult male and female frogs, which averaged 19.36 parasite individuals and 1.39 parasite species per adult frog, and had an overall prevalence of 77.52%. Acuariid larvae were likely acquired by O. septentrionalis in FL because they are not found in their native range. O. lenteixeirai was likely introduced because it is commonly reported in O. septentrionalis' native range but has never been reported in FL-native anurans. Aplectana sp. is also likely introduced because it has been reported in several anurans in Cuba but only reported once in Florida. O. septentrionalis tended to harbor fewer of its native parasites in the introduced range, which is consistent with the enemy release hypothesis and potentially creates an immunological advantage for this invasive host. Because native populations can be threatened by introduced parasites, there is a need to further explore the frequency and rate at which non-native hosts introduce parasites. PMID:26759792

An Indo-Pacific damselfish (Neopomacentrus cyanomos) in the Gulf of Mexico: origin and mode of introduction.

PubMed

Robertson, D Ross; Dominguez-Dominguez, Omar; Victor, Benjamin; Simoes, Nuno

2018-01-01

The Indo-West Pacific (IWP) coral-reef damselfish Neopomacentrus cyanomos is well established across the south-west Gulf of Mexico (SwGoMx). Comparisons of mtDNA sequences of the SwGoMx population with those from conspecifics from 16 sites scattered across its native geographic range show that the SwGoMx population is derived from two of four native lineages: one from the north-west Pacific Ocean, the other from the northern Indian Ocean. Three hypotheses address how this species was introduced to the SwGoMX: (1) aquarium release; (2) borne by cargo-ship; and (3) carried by offshore petroleum platform (petro-platform). The first is unlikely because this species rarely features in the aquarium trade, and " N. cyanomos " traded to the USA from the sole IWP source we are aware of are a misidentified congener, N. taeniurus . The second hypothesis is unlikely because shipping has not been associated with the introduction of alien damselfishes, there is little international shipping between the IWP and the SwGoMx, and voyages between those areas would be lengthy and along environmentally unfavorable routes. Various lines of evidence support the third hypothesis: (i) bio-fouled petro-platforms represent artificial reefs that can sustain large and diverse populations of tropical reef-fishes, including N. cyanomos in the SwGoMx; (ii) relocation of such platforms has been implicated in trans-oceanic introductions leading to establishment of non-native populations of such fishes; and (iii) genetic characteristics of the SwGoMx population indicate that it was established by a large and diverse group of founders drawn from the IWP regions where many petro-platforms currently in the SwGoMx and other Atlantic offshore oilfields originated.

An Indo-Pacific damselfish (Neopomacentrus cyanomos) in the Gulf of Mexico: origin and mode of introduction

PubMed Central

Dominguez-Dominguez, Omar; Victor, Benjamin; Simoes, Nuno

2018-01-01

The Indo-West Pacific (IWP) coral-reef damselfish Neopomacentrus cyanomos is well established across the south-west Gulf of Mexico (SwGoMx). Comparisons of mtDNA sequences of the SwGoMx population with those from conspecifics from 16 sites scattered across its native geographic range show that the SwGoMx population is derived from two of four native lineages: one from the north-west Pacific Ocean, the other from the northern Indian Ocean. Three hypotheses address how this species was introduced to the SwGoMX: (1) aquarium release; (2) borne by cargo-ship; and (3) carried by offshore petroleum platform (petro-platform). The first is unlikely because this species rarely features in the aquarium trade, and “N. cyanomos” traded to the USA from the sole IWP source we are aware of are a misidentified congener, N. taeniurus. The second hypothesis is unlikely because shipping has not been associated with the introduction of alien damselfishes, there is little international shipping between the IWP and the SwGoMx, and voyages between those areas would be lengthy and along environmentally unfavorable routes. Various lines of evidence support the third hypothesis: (i) bio-fouled petro-platforms represent artificial reefs that can sustain large and diverse populations of tropical reef-fishes, including N. cyanomos in the SwGoMx; (ii) relocation of such platforms has been implicated in trans-oceanic introductions leading to establishment of non-native populations of such fishes; and (iii) genetic characteristics of the SwGoMx population indicate that it was established by a large and diverse group of founders drawn from the IWP regions where many petro-platforms currently in the SwGoMx and other Atlantic offshore oilfields originated. PMID:29441235

Molecular Epidemiology and Genetic Variation of Pathogenic Vibrio parahaemolyticus in Peru

PubMed Central

Gavilan, Ronnie G.; Zamudio, Maria L.; Martinez-Urtaza, Jaime

2013-01-01

Vibrio parahaemolyticus is a foodborne pathogen that has become a public health concern at the global scale. The epidemiological significance of V. parahaemolyticus infections in Latin America received little attention until the winter of 1997 when cases related to the pandemic clone were detected in the region, changing the epidemic dynamics of this pathogen in Peru. With the aim to assess the impact of the arrival of the pandemic clone on local populations of pathogenic V. parahaemolyticus in Peru, we investigated the population genetics and genomic variation in a complete collection of non-pandemic strains recovered from clinical sources in Peru during the pre- and post-emergence periods of the pandemic clone. A total of 56 clinical strains isolated in Peru during the period 1994 to 2007, 13 strains from Chile and 20 strains from Asia were characterized by Multilocus Sequence Typing (MLST) and checked for the presence of Variable Genomic Regions (VGRs). The emergence of O3:K6 cases in Peru implied a drastic disruption of the seasonal dynamics of infections and a shift in the serotype dominance of pathogenic V. parahaemolyticus. After the arrival of the pandemic clone, a great diversity of serovars not previously reported was detected in the country, which supports the introduction of additional populations cohabitating with the pandemic group. Moreover, the presence of genomic regions characteristic of the pandemic clone in other non-pandemic strains may represent early evidence of genetic transfer from the introduced population to the local communities. Finally, the results of this study stress the importance of population admixture, horizontal genetic transfer and homologous recombination as major events shaping the structure and diversity of pathogenic V. parahaemolyticus. PMID:23696906

Discriminating the effects of spatial extent and population size in cyclic competition among species

NASA Astrophysics Data System (ADS)

Lamouroux, D.; Eule, S.; Geisel, T.; Nagler, J.

2012-08-01

We introduce a population model for species under cyclic competition. This model allows individuals to coexist and interact on single cells while migration takes place between adjacent cells. In contrast to the model introduced by Reichenbach, Mobilia, and Frey [Reichenbach, Mobilia, and Frey, Nature (London)NATUAS0028-083610.1038/nature06095 448, 1046 (2007)], we find that the emergence of spirals results in an ambiguous behavior regarding the stability of coexistence. The typical time until extinction exhibits, however, a qualitatively opposite dependence on the newly introduced nonunit carrying capacity in the spiraling and the nonspiraling regimes. This allows us to determine a critical mobility that marks the onset of this spiraling state sharply. In contrast, we demonstrate that the conventional finite size stability analysis with respect to spatial size is of limited use for identifying the onset of the spiraling regime.

The Certainty of Uncertainty: Potential Sources of Bias and Imprecision in Disease Ecology Studies.

PubMed

Lachish, Shelly; Murray, Kris A

2018-01-01

Wildlife diseases have important implications for wildlife and human health, the preservation of biodiversity and the resilience of ecosystems. However, understanding disease dynamics and the impacts of pathogens in wild populations is challenging because these complex systems can rarely, if ever, be observed without error. Uncertainty in disease ecology studies is commonly defined in terms of either heterogeneity in detectability (due to variation in the probability of encountering, capturing, or detecting individuals in their natural habitat) or uncertainty in disease state assignment (due to misclassification errors or incomplete information). In reality, however, uncertainty in disease ecology studies extends beyond these components of observation error and can arise from multiple varied processes, each of which can lead to bias and a lack of precision in parameter estimates. Here, we present an inventory of the sources of potential uncertainty in studies that attempt to quantify disease-relevant parameters from wild populations (e.g., prevalence, incidence, transmission rates, force of infection, risk of infection, persistence times, and disease-induced impacts). We show that uncertainty can arise via processes pertaining to aspects of the disease system, the study design, the methods used to study the system, and the state of knowledge of the system, and that uncertainties generated via one process can propagate through to others because of interactions between the numerous biological, methodological and environmental factors at play. We show that many of these sources of uncertainty may not be immediately apparent to researchers (for example, unidentified crypticity among vectors, hosts or pathogens, a mismatch between the temporal scale of sampling and disease dynamics, demographic or social misclassification), and thus have received comparatively little consideration in the literature to date. Finally, we discuss the type of bias or imprecision introduced by these varied sources of uncertainty and briefly present appropriate sampling and analytical methods to account for, or minimise, their influence on estimates of disease-relevant parameters. This review should assist researchers and practitioners to navigate the pitfalls of uncertainty in wildlife disease ecology studies.

ALIEN SPECIES: THEIR ROLE IN AMPHIBIAN POPULATION DECLINES AND RESTORATION

EPA Science Inventory

Alien species (also referred to as exotic, invasive, introduced, or normative species) have been implicated as causal agents in population declines of many amphibian species. Herein, we evaluate the relative contributions of alien species and other factors in adversely affecting ...

ASSESSING RISKS TO WILDLIFE POPULATIONS FROM MULTIPLE STRESSORS: OVERVIEW OF PROBLEM AND RESEARCH NEEDS

EPA Science Inventory

Wildlife populations are experiencing increasing pressure from human-induced changes in the landscape. Stressors including agricultural and urban land use, introduced invasive and exotic species, nutrient enrichment, direct human disturbance, and toxic chemicals directly or indi...

The coordination of problem solving strategies: when low competence sources exert more influence on task processing than high competence sources.

PubMed

Quiamzade, Alain; Mugny, Gabriel; Darnon, Céline

2009-03-01

Previous research has shown that low competence sources, compared to highly competent sources, can exert influence in aptitudes tasks in as much as they induce people to focus on the task and to solve it more deeply. Two experiments aimed at testing the coordination between self and source's problem solving strategies as a main explanation of such a difference in influence. The influence of a low versus high competence source has been examined in an anagram task that allows for distinguishing between three response strategies, including one that corresponds to the coordination between the source's strategy and participants' own strategy. In Study 1 the strategy suggested by the source was either relevant and useful or irrelevant and useless for solving the task. Results indicated that participants used the coordination strategy in a larger extend when they had been confronted to a low competence rather than a highly competent source but only when the source displayed a strategy that was useful to solve the task. In Study 2 the source's strategy was always relevant and useful, but a decentring procedure was introduced for half of the participants. This procedure induced participants to consider other points of view than their own. Results replicated the difference observed in Study 1 when no decentring was introduced. The difference however disappeared when decentring was induced, because of an increase of the high competence source's influence. These results highlight coordination of strategies as one mechanism underlying influence from low competence sources.

Nonlinear theory of shocked sound propagation in a nearly choked duct flow

NASA Technical Reports Server (NTRS)

Myers, M. K.; Callegari, A. J.

1982-01-01

The development of shocks in the sound field propagating through a nearly choked duct flow is analyzed by extending a quasi-one dimensional theory. The theory is applied to the case in which sound is introduced into the flow by an acoustic source located in the vicinity of a near-sonic throat. Analytical solutions for the field are obtained which illustrate the essential features of the nonlinear interaction between sound and flow. Numerical results are presented covering ranges of variation of source strength, throat Mach number, and frequency. It is found that the development of shocks leads to appreciable attenuation of acoustic power transmitted upstream through the near-sonic flow. It is possible, for example, that the power loss in the fundamental harmonic can be as much as 90% of that introduced at the source.

40 CFR 421.196 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Electrolyte. PSNS for the Secondary Indium Subcategory Pollutant or pollutant property Maximum for any 1 day... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Indium Subcategory... wastewater pollutants in secondary indium process wastewater introduced into a POTW should not exceed the...

40 CFR 421.196 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Electrolyte. PSNS for the Secondary Indium Subcategory Pollutant or pollutant property Maximum for any 1 day... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Indium Subcategory... wastewater pollutants in secondary indium process wastewater introduced into a POTW should not exceed the...

40 CFR 421.296 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin Subcategory... wastewater pollutants in secondary tin process wastewater introduced into a POTW shall not exceed the following values: (a) Tin smelter SO2 scrubber. PSNS for the Secondary Tin Subcategory Pollutant or...

40 CFR 421.296 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin Subcategory... wastewater pollutants in secondary tin process wastewater introduced into a POTW shall not exceed the following values: (a) Tin smelter SO2 scrubber. PSNS for the Secondary Tin Subcategory Pollutant or...

40 CFR 421.296 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin Subcategory... wastewater pollutants in secondary tin process wastewater introduced into a POTW shall not exceed the following values: (a) Tin smelter SO2 scrubber. PSNS for the Secondary Tin Subcategory Pollutant or...

40 CFR 421.296 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin Subcategory... wastewater pollutants in secondary tin process wastewater introduced into a POTW shall not exceed the following values: (a) Tin smelter SO2 scrubber. PSNS for the Secondary Tin Subcategory Pollutant or...

40 CFR 421.296 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Tin Subcategory... wastewater pollutants in secondary tin process wastewater introduced into a POTW shall not exceed the following values: (a) Tin smelter SO2 scrubber. PSNS for the Secondary Tin Subcategory Pollutant or...