scholarly journals Empirical assessment of a threshold model for sylvatic plague

2007 ◽  
Vol 4 (15) ◽  
pp. 649-657 ◽  
Author(s):  
S Davis ◽  
H Leirs ◽  
H Viljugrein ◽  
N.Chr Stenseth ◽  
L De Bruyn ◽  
...  
Keyword(s):  
Experimental Testing ◽  
Small Sample Size ◽  
Threshold Model ◽  
Strong Support ◽  
False Positives ◽  
Small Sample ◽  
Necessary Condition ◽  
Sylvatic Plague ◽  
Large Numbers ◽  
Rhombomys Opimus

Plague surveillance programmes established in Kazakhstan, Central Asia, during the previous century, have generated large plague archives that have been used to parameterize an abundance threshold model for sylvatic plague in great gerbil ( Rhombomys opimus ) populations. Here, we assess the model using additional data from the same archives. Throughout the focus, population levels above the threshold were a necessary condition for an epizootic to occur. However, there were large numbers of occasions when an epizootic was not observed even though great gerbils were, and had been, abundant. We examine six hypotheses that could explain the resulting false positive predictions, namely (i) including end-of-outbreak data erroneously lowers the estimated threshold, (ii) too few gerbils were tested, (iii) plague becomes locally extinct, (iv) the abundance of fleas was too low, (v) the climate was unfavourable, and (vi) a high proportion of gerbils were resistant. Of these, separate thresholds, fleas and climate received some support but accounted for few false positives and can be disregarded as serious omissions from the model. Small sample size and local extinction received strong support and can account for most of the false positives. Host resistance received no support here but should be subject to more direct experimental testing.

Soft-release versus hard-release for reintroduction of an endangered species: an experimental comparison using eastern barred bandicoots (Perameles gunnii)

2016 ◽  
Vol 43 (1) ◽  
pp. 1 ◽  
Author(s):  
Jasmine de Milliano ◽  
Julian Di Stefano ◽  
Peter Courtney ◽  
Peter Temple-Smith ◽  
Graeme Coulson
Keyword(s):  
Habitat Selection ◽  
Endangered Species ◽  
Experimental Testing ◽  
Small Sample Size ◽  
Small Sample ◽  
Statistical Testing ◽  
Experimental Comparison ◽  
Supplementary Food ◽  
Reintroduction Success ◽  
Release Method

Context Reintroduction is a popular tool for conserving endangered species, yet many attempts fail. Soft-release measures, including acclimatisation, have been used for many species around the world, based on the reasoning that gradual and supported reintroductions should improve the success of animals released into an unfamiliar wild environment. However, experimental testing of soft-release methods is rare. Aims To experimentally test the effect of a soft-release method versus a hard-release method on the initial reintroduction success of the eastern barred bandicoot (Perameles gunnii). Methods We released 12 captive-bred eastern barred bandicoots into a predator-proof reserve using two methods: soft-release (7 days of on-site acclimatisation with supplementary food before release) and hard-release (no acclimatisation and no supplementary food). We monitored the bandicoots intensively via radio-tracking and live-trapping for 4 weeks after release. Compared with hard-release bandicoots, we predicted that soft-release bandicoots would have (1) reduced movement (first night dispersal, site fidelity and activity range), (2) more directed patterns of habitat selection, (3) improved bodyweights and (4) improved survival. Key results There was no detectable difference in habitat selection, overall weight change and survival between the soft-release and hard-release groups. There was moderate evidence that, compared with the hard-release group, soft-release bandicoots moved less, demonstrated lower individual variation in all measures of movement, and lost weight more gradually after release. In most cases, effect sizes were moderate to large but had large standard errors owing to both small sample size and high variance. Consequently, statistical testing failed to detect significant differences at the 5% level. Conclusions Despite evidence that the release method influenced some of the monitored behaviours, soft-release did not confer a consistent and substantive advantage for captive-bred eastern barred bandicoots at our site. We conclude that soft-release is unlikely to improve overall reintroduction success for this species at fenced predator-free sites. Implications The present study suggests that the preferred option for reintroductions of eastern barred bandicoots to fenced sites is a hard-release, information that is now being used to guide reintroductions of this species. Similar experiments should be undertaken to improve reintroduction practice for other endangered species.

scholarly journals Anthropogenic and Natural Factors Affecting Trends in Atmospheric Methane in Barrow, Alaska

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 187
Author(s):  
Christopher Lawrence ◽  
Huiting Mao
Keyword(s):  
Small Sample Size ◽  
Strong Support ◽  
Warm Season ◽  
Growth Period ◽  
Complex Problem ◽  
Small Sample ◽  
Oil Field ◽  
Atmospheric Methane ◽  
Long Term Trends

This study examined the long-term trends in Arctic ambient methane (CH4) mixing ratios over 1986–2014 and investigated their potential causes. Significant correlations between carbon monoxide (CO) and CH4 in Barrow, Alaska (r = −0.59, p = 0.007) and Alert, Canada (r = −0.62, p =0.004) with the strongest correlations occurring in April (r = −0.81, p = 0.000, and r = −0.80, p = 0.000) suggest local to global anthropogenic contributions to ambient CH4 during the cold months. Backward trajectories indicate a significant influence (27% of total trajectories) of local emissions from the Prudhoe Bay Oil Field on ambient CH4 in Barrow in winter, and this influence was dominated by other factors in summer. The mean CH4 wetland emission flux in Barrow over 1986–2014 was estimated to be 0.008 ± 0.002 µg m−2 s−1 while in Tiksi, Russia it was 0.010 µg m−2 s−1 over 2012–2016, which is comparable to the lower end of measurements in the literature. Note that in Barrow, there was a decrease in wetland flux from 0.0083 ± 0.002 µg m−2 s−1 over 1986–1998 to 0.0077 ± 0.002 µg m−2 s−1 from 1999–2006 followed by an increase to 0.0081 ± 0.002 µg m−2 s−1 over 2007–2014. Although the difference between the three values is not statistically significant due to small sample size, it is indicative of possible warm season wetland emissions contributing to the zero-growth period. Strong support for this hypothesis is that these changes are consistent with a concurrent drop in summertime temperature possibly causing a decrease in wetland emissions over 1998–2006 based on the statistically significant correlations between temperature and CH4 during August through November (r~0.36–0.56, p= ≤ 0.05). In a warming climate, permafrost thawing can increase CH4 wetland emissions and also decrease wetlands making it a complex problem, and, hence, further study is needed to better understand the mechanisms driving long-term trends in Arctic CH4.

Inclusive growth in Africa: are Chinese investment and local industry participation compatible?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Emmanuel T. Kodzi Jr
Keyword(s):  
Small Sample Size ◽  
Value Added ◽  
Principal Component ◽  
Small Sample ◽  
Necessary Condition ◽  
Inclusive Growth ◽  
Host Countries ◽  
African Countries ◽  
Content Type ◽  
Chinese Investment

PurposeThis paper aims to explore whether increasing Chinese foreign direct investment (FDI) is associated with rising contributions of local industry in African countries connected to the Belt and Road Initiative (BRI). The existence of cooperative industry linkages between Chinese investments and local businesses is a necessary condition for achieving the mutual benefits asserted by the BRI.Design/methodology/approachUnder growing FDI, the authors framed increasing local industry contribution as indicative of existing industry linkages. Using principal component analysis and multiple regression on collated country-level data, the authors examined relationships between key industry output variables and several independent variables representing Chinese investment and economic activity in a contiguous three-country region, over two investment periods.FindingsIncreasing Chinese FDI was associated with positive economic outcomes including decreasing unemployment; however, it did not appear to support local industry participation. The authors identified a “China effect” that hampered industry contribution to gross domestic product. The authors found that attempting to counterbalance this effect through direct exports to China was not strategically sound. Similarly, export-focused clusters in special zones may not foster industry linkages if they result in isolationism. Rather, host countries have an opportunity to enhance local industry contribution through leveraging interconnectivity factors under increasing FDI.Research limitations/implicationsSmall sample size of the study has implications for the predictive power of the model and for the complete explanation all the emerging findings. However, the authors presented compelling arguments for selecting the specific three countries. By conducting robustness checks on a separate region, findings of this study were substantially corroborated.Practical implicationsInstead of exporting directly to China as a way to mitigate local industry contraction, host countries need to thoughtfully pursue opportunities that present the greatest value-added export advantages. Proposed Chinese-funded infrastructure projects must be negotiated with a goal to strategically reduce interconnectivity barriers and achieve broader logistics improvements in the host countries.Social implicationsThe study provides a tool for proponents of local industry growth to present clearer frameworks in their advocacy. The social tensions around Chinese dominance in the host countries can be reduced by understanding and pursuing levers that enhance industry contribution in those contexts.Originality/valueThis study takes a different approach to examining the professed win-win proposition of the BRI in Africa. It uncovers important effects of increasing Chinese FDI and addresses viable host country responses, including a clear pathway for forging the cooperative industry linkages needed for inclusive growth and sustainable development.

scholarly journals Archaeologic Machine Learning for Shipwreck Detection Using Lidar and Sonar

2021 ◽  
Vol 13 (9) ◽  
pp. 1759
Author(s):  
Leila Character ◽  
Agustin Ortiz JR ◽  
Tim Beach ◽  
Sheryl Luzzadder-Beach
Keyword(s):  
Small Sample Size ◽  
Geographic Area ◽  
The United States ◽  
False Positives ◽  
Small Sample ◽  
Underwater Archaeology ◽  
Morphologic Characteristics ◽  
Digital Elevation ◽  
Elevation Data ◽  
Large Geographic Area

The objective of this project is to create a new implementation of a deep learning model that uses digital elevation data to detect shipwrecks automatically and rapidly over a large geographic area. This work is intended to apply a new methodology to the field of underwater archaeology. Shipwrecks represent a major resource to understand maritime human activity over millennia, but underwater archaeology is expensive, misappropriated, and hazardous. An automated tool to rapidly detect and map shipwrecks can therefore be used to create more accurate maps of natural and archaeological features to aid management objectives, study patterns across the landscape, and find new features. Additionally, more comprehensive and accurate shipwreck maps can help to prioritize site selection and plan excavation. The model is based on open source topo-bathymetric data and shipwreck data for the United States available from NOAA. The model uses transfer learning to compensate for a relatively small sample size and addresses a recurring problem that associated work has had with false positives by training the model both on shipwrecks and background topography. Results of statistical analyses conducted—ANOVAs and box and whisker plots—indicate that there are substantial differences between the morphologic characteristics that define shipwrecks vs. background topography, supporting this approach to addressing false positives. The model uses a YOLOv3 architecture and produced an F1 score of 0.92 and a precision score of 0.90, indicating that the approach taken herein to address false positives was successful.

Probing the ultrastructure of the mitotic and meiotic spindle in eggs: An expeditious approach based on semi-thin (0.25 μm) serial sections

1983 ◽  
Vol 41 ◽  
pp. 552-555
Author(s):  
Conly L. Rieder ◽  
S. Bowser ◽  
R. Nowogrodzki ◽  
K. Ross ◽  
G. Sluder
Keyword(s):  
Small Sample Size ◽  
Small Sample ◽  
Meiotic Spindle ◽  
Serial Sections ◽  
Mitotic Apparatus ◽  
Thin Sections ◽  
Cell Cycles ◽  
Ultrastructural Studies

Eggs have long been a favorite material for studying the mechanism of karyokinesis in-vivo and in-vitro. They can be obtained in great numbers and, when fertilized, divide synchronously over many cell cycles. However, they are not considered to be a practical system for ultrastructural studies on the mitotic apparatus (MA) for several reasons, the most obvious of which is that sectioning them is a formidable task: over 1000 ultra-thin sections need to be cut from a single 80-100 μm diameter egg and of these sections only a small percentage will contain the area or structure of interest. Thus it is difficult and time consuming to obtain reliable ultrastructural data concerning the MA of eggs; and when it is obtained it is necessarily based on a small sample size.We have recently developed a procedure which will facilitate many studies concerned with the ultrastructure of the MA in eggs. It is based on the availability of biological HVEM's and on the observation that 0.25 μm thick serial sections can be screened at high resolution for content (after mounting on slot grids and staining with uranyl and lead) by phase contrast light microscopy (LM; Figs 1-2).

Validating the Factor Structure of the Stigma of Suicide Scale–Short Form Spanish Version Among Healthcare Students

Crisis ◽  
2020 ◽  
pp. 1-5
Author(s):  
Ruthmarie Hernández-Torres ◽  
Paola Carminelli-Corretjer ◽  
Nelmit Tollinchi-Natali ◽  
Ernesto Rosario-Hernández ◽  
Yovanska Duarté-Vélez ◽  
...  
Keyword(s):  
Factor Structure ◽  
Structural Equation ◽  
Short Form ◽  
Small Sample Size ◽  
Small Sample ◽  
Spanish Version ◽  
Equation Modeling ◽  
Cross Sectional ◽  
Healthcare Students ◽  
Spanish Speaking

Abstract. Background: Suicide is a leading cause of death among Spanish-speaking individuals. Suicide stigma can be a risk factor for suicide. A widely used measure is the Stigma of Suicide Scale-Short Form (SOSS-SF; Batterham, Calear, & Christensen, 2013 ). Although the SOSS-SF has established psychometric properties and factor structure in other languages and cultural contexts, no evidence is available from Spanish-speaking populations. Aim: This study aims to validate a Spanish translation of the SOSS-SF among a sample of Spanish-speaking healthcare students ( N = 277). Method: We implemented a cross-sectional design with quantitative techniques. Results: Following a structural equation modeling approach, a confirmatory factor analysis (CFA) supported the three-factor model proposed by Batterham and colleagues (2013) . Limitations: The study was limited by the small sample size and recruitment by availability. Conclusion: Findings suggest that the Spanish version of the SOSS-SF is a valid and reliable tool with which to examine suicide stigma among Spanish-speaking populations.

An Initial Investigation of Suicide Attempt Disclosures Among US Veterans

Crisis ◽  
2020 ◽  
pp. 1-7
Author(s):  
Brooke A. Ammerman ◽  
Sarah P. Carter ◽  
Heather M. Gebhardt ◽  
Jonathan Buchholz ◽  
Mark A. Reger
Keyword(s):  
Suicide Attempt ◽  
Mental Health Professionals ◽  
Help Seeking ◽  
Psychiatric Treatment ◽  
Small Sample Size ◽  
Romantic Partners ◽  
Small Sample ◽  
Professional Care ◽  
Patient Disclosure ◽  
Previous Suicide Attempt

Abstract. Background: Patient disclosure of prior suicidal behaviors is critical for effectively managing suicide risk; however, many attempts go undisclosed. Aims: The current study explored how responses following a suicide attempt disclosure may relate to help-seeking outcomes. Method: Participants included 37 veterans with a previous suicide attempt receiving inpatient psychiatric treatment. Veterans reported on their most and least helpful experiences disclosing their suicide attempt to others. Results: Veterans disclosed their suicide attempt to approximately eight individuals. Mental health professionals were the most cited recipient of their most helpful disclosure; romantic partners were the most common recipient of their least helpful disclosures. Positive reactions within the context of the least helpful disclosure experience were positively associated with a sense of connection with the disclosure recipient. Positive reactions within the most helpful disclosure experience were positively associated with the likelihood of future disclosure. No reactions were associated with having sought professional care or likelihood of seeking professional care. Limitations: The results are considered preliminary due to the small sample size. Conclusion: Findings suggest that while positive reactions may influence suicide attempt disclosure experiences broadly, additional research is needed to clarify factors that drive the decision to disclose a suicide attempt to a professional.

Investigating the Dynamics of Suicidal Ideation

Crisis ◽  
2018 ◽  
Vol 39 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Nina Hallensleben ◽  
Lena Spangenberg ◽  
Thomas Forkmann ◽  
Dajana Rath ◽  
Ulrich Hegerl ◽  
...  
Keyword(s):  
Suicidal Ideation ◽  
Small Sample Size ◽  
Unipolar Depression ◽  
Small Sample ◽  
History Of ◽  
Severity Of Depression ◽  
Ecological Momentary ◽  
Depressive Episodes ◽  
Ema Method ◽  
Shed Light

Abstract. Background: Although the fluctuating nature of suicidal ideation (SI) has been described previously, longitudinal studies investigating the dynamics of SI are scarce. Aim: To demonstrate the fluctuation of SI across 6 days and up to 60 measurement points using smartphone-based ecological momentary assessments (EMA). Method: Twenty inpatients with unipolar depression and current and/or lifetime suicidal ideation rated their momentary SI 10 times per day over a 6-day period. Mean squared successive difference (MSSD) was calculated as a measure of variability. Correlations of MSSD with severity of depression, number of previous depressive episodes, and history of suicidal behavior were examined. Results: Individual trajectories of SI are shown to illustrate fluctuation. MSSD values ranged from 0.2 to 21.7. No significant correlations of MSSD with several clinical parameters were found, but there are hints of associations between fluctuation of SI and severity of depression and suicidality. Limitations: Main limitation of this study is the small sample size leading to low power and probably missing potential effects. Further research with larger samples is necessary to shed light on the dynamics of SI. Conclusion: The results illustrate the dynamic nature and the diversity of trajectories of SI across 6 days in psychiatric inpatients with unipolar depression. Prediction of the fluctuation of SI might be of high clinical relevance. Further research using EMA and sophisticated analyses with larger samples is necessary to shed light on the dynamics of SI.

Participant Reactions to Suicide-Focused Research

Crisis ◽  
2020 ◽  
Vol 41 (5) ◽  
pp. 367-374
Author(s):  
Sarah P. Carter ◽  
Brooke A. Ammerman ◽  
Heather M. Gebhardt ◽  
Jonathan Buchholz ◽  
Mark A. Reger
Keyword(s):  
Medical Records ◽  
Research Study ◽  
Small Sample Size ◽  
Psychiatric Inpatient ◽  
Small Sample ◽  
Inpatient Unit ◽  
Online Laboratory ◽  
Psychiatric Inpatient Unit ◽  
Before And After ◽  
Participant Reactions

Abstract. Background: Concerns exist regarding the perceived risks of conducting suicide-focused research among an acutely distressed population. Aims: The current study assessed changes in participant distress before and after participation in a suicide-focused research study conducted on a psychiatric inpatient unit. Method: Participants included 37 veterans who were receiving treatment on a psychiatric inpatient unit and completed a survey-based research study focused on suicide-related behaviors and experiences. Results: Participants reported no significant changes in self-reported distress. The majority of participants reported unchanged or decreased distress. Reviews of electronic medical records revealed no behavioral dysregulation and minimal use of as-needed medications or changes in mood following participation. Limitations: The study's small sample size and veteran population may limit generalizability. Conclusion: Findings add to research conducted across a variety of settings (i.e., outpatient, online, laboratory), indicating that participating in suicide-focused research is not significantly associated with increased distress or suicide risk.

Measurements method of the audio recordings acoustic quality indicator prepared for registration and processing in the Unified Biometric System

2019 ◽  
pp. 40-46 ◽  
Author(s):  
V.V. Savchenko ◽  
A.V. Savchenko
Keyword(s):  
Quality Control ◽  
Small Sample Size ◽  
Personal Data ◽  
Digital Processing ◽  
Small Sample ◽  
Practical Implementation ◽  
Acoustic Measurements ◽  
Pitch Frequency ◽  
Wide Range ◽  
Automated Quality Control

We consider the task of automated quality control of sound recordings containing voice samples of individuals. It is shown that in this task the most acute is the small sample size. In order to overcome this problem, we propose the novel method of acoustic measurements based on relative stability of the pitch frequency within a voice sample of short duration. An example of its practical implementation using aninter-periodic accumulation of a speech signal is considered. An experimental study with specially developed software provides statistical estimates of the effectiveness of the proposed method in noisy environments. It is shown that this method rejects the audio recording as unsuitable for a voice biometric identification with a probability of 0,95 or more for a signal to noise ratio below 15 dB. The obtained results are intended for use in the development of new and modifying existing systems of collecting and automated quality control of biometric personal data. The article is intended for a wide range of specialists in the field of acoustic measurements and digital processing of speech signals, as well as for practitioners who organize the work of authorized organizations in preparing for registration samples of biometric personal data.

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