scholarly journals Integrating small population effects on both detection and persistence probabilities in the design and interpretation of presence/absence surveys.

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 234
Author(s):  
Brian R. Hudgens ◽  
David K. Garcelon
Keyword(s):  
Population Size ◽  
National Parks ◽  
Disease Risk ◽  
Small Population ◽  
Negative Results ◽  
Extinction Probabilities ◽  
Ecological Applications ◽  
Elusive Species ◽  
Near Future ◽  
Population Effects

Determining whether or not a species has been extirpated from part of its range is one of the most important yet difficult challenges facing ecologists.  Presence/absence surveys are a primary method to determine local extinction, but negative results are difficult to interpret, particularly when informal sightings appear to support local persistence of elusive species.  Such conflicts are particularly likely for rare species, which are the most difficult to detect during a presence/absence survey due to small population size.  However, integrating small population effects on both detection and extinction probabilities resolves such conflicts by reframing occupancy questions from present to near future terms.  We developed methods for integrating the simultaneous effects of survey effort and population size on detection and extinction probabilities in the design and interpretation of presence/absence surveys.  We applied these methods to the design and interpretation of a wolverine survey in Sequoia-Kings Canyon National Parks, California, USA, to address questions about the appropriateness of translocations from other populations.  Ecological applications that can benefit from this type of analysis, simultaneously incorporating small population effects on both detection and population processes, include management of charismatic, yet elusive species, management of disease risk in translocations, and management of nonnative pests.

Evolutionary genetics of small populations

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Evolutionary Genetics ◽  
Small Population ◽  
Small Populations ◽  
Effective Population ◽  
Genetic Management ◽  
Evolutionary Genetic ◽  
Loss Of Genetic Diversity ◽  
Number Of Individuals

Genetic management of fragmented populations involves the application of evolutionary genetic theory and knowledge to alleviate problems due to inbreeding and loss of genetic diversity in small population fragments. Populations evolve through the effects of mutation, natural selection, chance (genetic drift) and gene flow (migration). Large outbreeding, sexually reproducing populations typically contain substantial genetic diversity, while small populations typically contain reduced levels. Genetic impacts of small population size on inbreeding, loss of genetic diversity and population differentiation are determined by the genetically effective population size, which is usually much smaller than the number of individuals.

Genetic and Nongenetic Bases for the L-Shaped Distribution of Quantitative Trait Loci Effects

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1773-1787 ◽  
Author(s):  
Bruno Bost ◽  
Dominique de Vienne ◽  
Frédéric Hospital ◽  
Laurence Moreau ◽  
Christine Dillmann
Keyword(s):  
Linkage Disequilibrium ◽  
Quantitative Trait Loci ◽  
Population Size ◽  
Quantitative Trait ◽  
Metabolic Flux ◽  
Genetic Model ◽  
Small Population ◽  
Additive Genetic Model ◽  
Metabolic Mechanism ◽  
Qtl Effects

Abstract The L-Shaped distribution of estimated QTL effects (R2) has long been reported. We recently showed that a metabolic mechanism could account for this phenomenon. But other nonexclusive genetic or nongenetic causes may contribute to generate such a distribution. Using analysis and simulations of an additive genetic model, we show that linkage disequilibrium between QTL, low heritability, and small population size may also be involved, regardless of the gene effect distribution. In addition, a comparison of the additive and metabolic genetic models revealed that estimates of the QTL effects for traits proportional to metabolic flux are far less robust than for additive traits. However, in both models the highest R2's repeatedly correspond to the same set of QTL.

scholarly journals Population Density or Populations Size. Which Factor Determines Urban Traffic Congestion?

2021 ◽  
Vol 13 (8) ◽  
pp. 4280
Author(s):  
Yu Sang Chang ◽  
Sung Jun Jo ◽  
Yoo-Taek Lee ◽  
Yoonji Lee
Keyword(s):  
Population Density ◽  
Population Size ◽  
Traffic Congestion ◽  
Critical Role ◽  
Small Population ◽  
High Density ◽  
Urban Traffic ◽  
Contradictory Result ◽  
Low Density

A large number of articles have documented that as population density of cities increases, car use declines and public transit use rises. These articles had a significant impact of promoting high-density compact urban development to mitigate traffic congestion. Another approach followed by other researchers used the urban scaling model to indicate that traffic congestion increases as population size of cities increases, thus generating a possible contradictory result. Therefore, this study examines the role of both density and population size on traffic congestion in 164 global cities by the use of Stochastic Impacts by Regression on Population, Affluence and Technology model. We divide 164 cities into the two subgroups of 66 low density cities and 98 high density cities for analysis. The findings from the subgroups analysis indicated a clear-cut difference on the critical role of density in low-density cities and the exclusive role of population size in high-density cities. Furthermore, using threshold regression model, 164 cities are divided into the two regions of large and small population cities to determine population scale advantage of traffic congestion. Our findings highlight the importance of including analysis of subgroups based on density and/or population size in future studies of traffic congestion.

Eumops floridanus (Chiroptera: Molossidae)

2021 ◽  
Vol 53 (1009) ◽  
pp. 125-133
Author(s):  
Jessica M Vannatta ◽  
Jeffery A Gore ◽  
Verity L Mathis ◽  
Brian D Carver
Keyword(s):  
United States ◽  
Population Size ◽  
The United States ◽  
Small Population ◽  
Species Level ◽  
Small Population Size ◽  
Restricted Distribution ◽  
Dead Trees ◽  
Fish And Wildlife Service

Abstract Eumops floridanus (Allen, 1932) is a molossid commonly called the Florida bonneted bat or the Florida mastiff bat. Eumops floridanus is the largest species of bat in Florida and is one of 16 species in the genus Eumops. With one of the smallest distributions of any bat in the United States, it is endemic to southern peninsular Florida where it roosts in cavities of live and dead trees and man-made structures. Eumops floridanus was formerly classified as a subspecies of E. glaucinus but has been elevated to species level based on morphology. Due primarily to its restricted distribution, small population size, and the continued loss of habitat, E. floridanus is federally listed as “Endangered” (EN) by the United States Fish and Wildlife Service.

scholarly journals Clipperton Atoll as a model to study small marine populations: Endemism and the genomic consequences of small population size

PLoS ONE ◽  
2018 ◽  
Vol 13 (6) ◽  
pp. e0198901 ◽  
Author(s):  
Nicole L. Crane ◽  
Juliette Tariel ◽  
Jennifer E. Caselle ◽  
Alan M. Friedlander ◽  
D. Ross Robertson ◽  
...  
Keyword(s):  
Population Size ◽  
Small Population ◽  
Small Population Size

scholarly journals A Novel Strategy to Identify Haematology Patients at High Risk of Developing Aspergillosis

2021 ◽  
Vol 12 ◽  
Author(s):  
James S. Griffiths ◽  
P. Lewis White ◽  
Aiysha Thompson ◽  
Diogo M. da Fonseca ◽  
Robert J. Pickering ◽  
...  
Keyword(s):  
High Risk ◽  
Disease Risk ◽  
Low Risk ◽  
Fungal Resistance ◽  
Haematopoietic Stem Cell ◽  
Cell Transplant ◽  
Negative Results ◽  
Risk Patients ◽  
Haematology Patients ◽  
Anti Fungal

Invasive Aspergillosis (IA), typically caused by the fungus Aspergillus fumigatus, is a leading cause of morbidity and mortality in immunocompromised patients. IA remains a significant burden in haematology patients, despite improvements in the diagnosis and treatment of Aspergillus infection. Diagnosing IA is challenging, requiring multiple factors to classify patients into possible, probable and proven IA cohorts. Given the low incidence of IA, using negative results as exclusion criteria is optimal. However, frequent false positives and severe IA mortality rates in haematology patients have led to the empirical use of toxic, drug-interactive and often ineffective anti-fungal therapeutics. Improvements in IA diagnosis are needed to reduce unnecessary anti-fungal therapy. Early IA diagnosis is vital for positive patient outcomes; therefore, a pre-emptive approach is required. In this study, we examined the sequence and expression of four C-type Lectin-like receptors (Dectin-1, Dectin-2, Mincle, Mcl) from 42 haematology patients and investigated each patient’s anti-Aspergillus immune response (IL-6, TNF). Correlation analysis revealed novel IA disease risk factors which we used to develop a pre-emptive patient stratification protocol to identify haematopoietic stem cell transplant patients at high and low risk of developing IA. This stratification protocol has the potential to enhance the identification of high-risk patients whilst reducing unnecessary treatment, minimizing the development of anti-fungal resistance, and prioritising primary disease treatment for low-risk patients.

Partial Splenectomy for Staging Hodgkin's Disease: Risk of False-Negative Results

1978 ◽  
Vol 299 (7) ◽  
pp. 345-346 ◽  
Author(s):  
James C Dearth ◽  
Gerald S. Gilchrist ◽  
Robert L. Telander ◽  
Michael J. O'Connell ◽  
Louis H. Weiland
Keyword(s):  
Hodgkin's Disease ◽  
Disease Risk ◽  
Hodgkin’S Disease ◽  
False Negative ◽  
Partial Splenectomy ◽  
Negative Results ◽  
False Negative Results

while the opposite was expected for the latter. Men were expected to exhibit no change. In fact, no systematic change in any variable was observed for any group. Even unsystematic change was minimal. This suggests that the survey instrument is highly reliable, but it does not support the biological hypothesis for political orientations. Attempts to test biological explanations of observed political behavior are reasonable enough given the underdeveloped status of the research. Testing for biological roots of male-female political differences is justified by extant literature. Given this, what inter-pretation should be placed on the negative empirical results just reported? One might conclude that reasonable though the attempt may have been, there is little justification for further work in this field. Indeed, at least by implication, the case for cultural explana-tions of sex differences in politics is strengthened. If negative results can stimulate more imaginative inquiry into cultural explanation, they still serve a very useful purpose, for there is much to be done here. Similarly, though they should not have been deterred by positive findings, persons who seek more equitable status for women through modification of the cultural environment may take heart from this, for it does underscore the likely efficacy of their strategy. There are other implications to this effort. First, it is possible to do actual research about the importance of biological variables in political behavior. The process does not have to be difficult; ques-tions generated by the literature are amenable to straightforward research. One study producing negative results in a single area can-not represent closure across the whole broad question of biology and political behavior. Hopefully this work will stimulate further think-ing on related concepts in the discipline. Finally, it is unlikely that the question of whether there are biological roots to male-female political differences will be regarded as definitively settled at any time in the near future. Perhaps this will encourage measured, re-sponsible research into the matter; it would not do to leave this area of inquiry entirely to chauvinists and polemicists. NOTES

2012 ◽  
pp. 152-220
Keyword(s):  
Sex Differences ◽  
Political Behavior ◽  
Systematic Change ◽  
Cultural Environment ◽  
Negative Results ◽  
Biological Variables ◽  
Political Orientations ◽  
Cultural Explanation ◽  
Political Differences ◽  
Near Future

Is Its Success Generalizable?

2019 ◽  
pp. 72-93
Author(s):  
Lane Kenworthy
Keyword(s):  
Income Inequality ◽  
Population Size ◽  
Labor Unions ◽  
Low Income ◽  
Work Ethic ◽  
Unique Feature ◽  
Tax Compliance ◽  
Small Population ◽  
Close Inspection ◽  
Social Democratic

Abstract: Social democratic capitalism’s chief practitioners have been the Nordic nations: Denmark, Finland, Norway, and Sweden. Skeptics discount the Nordics’ success on the presumption that these nations have some unique feature that allows them, and only them, to reap the benefits of social democratic policies without suffering tradeoffs. Versions of this story identify the Nordics’ secret weapon as an immutable work ethic, superior intelligence, trust, solidarity, small population size, racial and ethnic homogeneity, institutional coherence, effective government, corporatism, a willingness to be taxed, tax compliance, strong labor unions, or low income inequality. I examine these hypotheses. None holds up to close inspection.

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