bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gains and Losses affect Learning Differentially at Low and High Attentional Load
Authors: Boroujeni Kianoush Banaie , Watson Marcus , Womelsdorf Thilo 
Published: September 2020

AbstractProspective gains and losses modulate cognitive processing, but it is unresolved whether gains and losses can facilitate flexible learning in changing environments. The prospect of gains might enhance flexible learning through prioritized processing of reward-predicting stimuli but is unclear how far this learning benefit extends when task demands increase. Similarly, experiencing losses might facilitate learning when they trigger attentional re-orienting away from loss-inducing stimuli, but losses may also impair learning by reducing the precise encoding of loss-inducing stimuli. To clarify these divergent views, we tested how varying magnitudes of gains and losses affect the flexible learning of object values in environments that varied attentional load by increasing the number of interfering object features during learning. With this task design we found that larger prospective gains improved learning efficacy and learning speed, but only when attentional load was low. In contrast, expecting losses generally impaired learning efficacy and this impairment was larger at higher attentional load. These findings functionally dissociate the contributions of prospective gains and losses on flexible learning, suggesting they operate via separate control mechanisms. One process is triggered by experiencing loss and seems to disrupt the encoding of specific loss-inducing features which leads to less efficient exploration during learning. The second process is triggered by experiencing gains which enhances learning through a more efficient prioritizing of reward-predicting stimulus features as long as the interference of distracting information is limited. These results demonstrate strengths and limitations of motivational regulation of learning efficacy in multidimensional environments having variable attentional loads.Significance statementIncreasing the prospective gains is assumed to enhance flexible learning, but there is no consensus on whether imposing losses enhances or impairs flexible learning. We show that anticipating loss of already attained assets generally reduced learning changes in the relevance of visual objects and that this learning impediment is more pronounced when learning demands higher attentional control of interference from distracting object features. Moreover, we show that increasing the prospective gains indeed facilitates learning, but only when the learning problem has intermediate or low attentional demands. These findings document that the beneficial effects of gains hit a limit when task demands increase, and that prospective losses reduce cognitive flexibility already at low task demands which is exacerbated when task demands increase. These findings provide novel insight into the strengths and limitations of gains and of losses to support flexible learning in multidimensional environments imposing variable attentional loads.
An intestinal cell type in zebrafish is the nexus for the SARS-CoV-2 receptor and the Renin-Angiotensin-Aldosterone System that contributes to COVID-19 comorbidities
Authors: Postlethwait John H. , Farnsworth Dylan R. , Miller Adam C. 
Published: September 2020

ABSTRACTPeople with underlying conditions, including hypertension, obesity, and diabetes, are especially susceptible to negative outcomes after infection with the coronavirus SARS-CoV-2. These COVID-19 comorbidities are exacerbated by the Renin-Angiotensin-Aldosterone System (RAAS), which normally protects from rapidly dropping blood pressure or dehydration via the peptide Angiotensin II (Ang II) produced by the enzyme Ace. The Ace paralog Ace2 degrades Ang II, thus counteracting its chronic effects. Ace2 is also the SARS-CoV-2 receptor.Ace, the coronavirus, and COVID-19 comorbidities all regulateAce2, but we don’t yet understand how. To exploit zebrafish (Danio rerio) as a disease model to understand mechanisms regulating the RAAS and its relationship to COVID-19 comorbidities, we must first identify zebrafish orthologs and co-orthologs of human RAAS genes, and second, understand where and when these genes are expressed in specific cells in zebrafish development. To achieve these goals, we conducted genomic analyses and investigated single cell transcriptomes. Results showed that most human RAAS genes have an ortholog in zebrafish and some have two or more co-orthologs. Results further identified a specific intestinal cell type in zebrafish larvae as the site of expression for key RAAS components, including Ace, Ace2, the coronavirus co-receptor Slc6a19, and the Angiotensin-related peptide cleaving enzymes Anpep and Enpep. Results also identified specific vascular cell subtypes as expressing Ang II receptors,apelin, andapelin receptorgenes. These results identify specific genes and cell types to exploit zebrafish as a disease model for understanding the mechanisms leading to COVID-19 comorbidities.SUMMARY STATEMENTGenomic analyses identify zebrafish orthologs of the Renin-Angiotensin-Aldosterone System that contribute to COVID-19 comorbidities and single-cell transcriptomics show that they act in a specialized intestinal cell type.
C1 compounds shape the microbial community of an abandoned century-old oil exploration well
Authors: Rojas-Gätjens Diego , Fuentes-Schweizer Paola , Rojas-Jimenez Keilor , Pérez-Pantoja Danilo , Avendaño Roberto , Alpízar Randall , Coronado-Ruíz Carolina , Chavarría Max 
Published: September 2020

AbstractThe search for microorganisms that degrade hydrocarbons is highly relevant because it enables the bioremediation of these substances cheaply and without dangerous by-products. In this work, we studied the microbial communities of an exploratory oil well, abandoned a century ago, located in the Cahuita National Park of Costa Rica. Cahuita well is characterized by a continuous efflux of methane and the presence of a mixture of hydrocarbons including C2-dibenzothiophene, phenanthrene or anthracene, fluoranthene pyrene, dibenzothiophene, tricyclic terpanes, pyrene, sesquiterpenes, sterane and n-alkanes. Based on the analysis of 16S rRNA gene amplicons, we detected a significant abundance of methylotrophic bacteria (Methylobacillus(6.3-26.0 % of total reads) andMethylococcus(4.1-30.6 %)) and the presence of common genera associated with hydrocarbon degradation, such asComamonas(0.8-4.6 %),Hydrogenophaga(1.5-3.3 %)Rhodobacter(1.0-4.9 %) andFlavobacterium(1.1-6.5 %). We evidenced the presence of methane monooxygenase (MMO) activities, responsible for the first step in methane metabolism, by amplifying thepmogene from environmental DNA. We also isolated a strain ofMethylorubrum rhodesianum, which was capable of using methanol as its sole carbon source. This work represents a contribution to the understanding of the ecology of communities of microorganisms in environments with permanently high concentrations of methane and hydrocarbons, which also has biotechnological implications for the bioremediation of highly polluting petroleum components.
Response of endolithic Chroococcidiopsis strains from the polyextreme Atacama Desert to light radiation
Authors: Casero María Cristina , Ascaso Carmen , Quesada Antonio , Mazur-Marzec Hanna , Wierzchos Jacek 
Published: September 2020

AbstractThe Atacama Desert is known to be the place on Earth with one of the highest solar radiation limiting the presence of life to endolithic microhabitats and soil microbial ecosystems. Endolithic microbial communities are supported by photosynthetic primary producers, mainly cyanobacteria, which can be injured by UVR. Nevertheless, cyanobacteria exposed to high solar radiation and its harmful effects have developed a series of defense mechanisms: avoidance, antioxidant systems or production of photoprotective compounds such as scytonemin among others. Scytonemin is a liposoluble pigment whose absorption maxima are located in UVA and UVC range and highly absorbing in the UVB range. In order to elucidate the protection capacity of endolithic cyanobacteria against harmful radiation, two cyanobacterial strains from Chroococcidiopsis genus were isolated from different endolithic microhabitats in the Atacama Desert: UAM813 strain, originally from the cryptoendolithic microhabitat of halite (NaCl), and UAM816 strain from chasmoendolithic microhabitat of calcite (CaCO3). Both were exposed to PAR and UVR+PAR conditions studying their short-term response, as oxidative stress and long-term response, as scytonemin production, metabolic activity and ultrastructural damage. The observed response of both strains reveals a high sensitivity to direct light exposure, even to PAR. The differences in their acclimation suggest specific adaptation strategies related to their original microhabitat, revealing their protective potential and the strain specific environmental pressure selection to inhabit different microhabitats and exposed to different light conditions.ImportanceCyanobacteria are photosynthetic prokaryotes that inhabit most types of illuminated environments, even the endolithic microhabitats in cold and hot deserts. The environmental pressure caused by the extreme solar irradiation in the Atacama Desert involve that only those cyanobacterial strains able to cope with it can be found in these endolithic communities, usually dominated by members belonging to the extremotolerant Chroococcidiopsis genus. Here, a comprehensive analysis of multiple lines of defense against harmful sun radiation was conducted to diagnose the response of two Chroococcidiopsis strains isolated from different endolithic microhabitats and lithic substrates, and identify its relation with the original microenvironmental conditions of each strain. Our results contribute to a better understanding of the acclimation strategies developed by these cyanobacterial strains and its potential protective role for the whole endolithic microbial community.
Pharmacokinetics and predicted neutralization coverage of VRC01 in HIV-uninfected participants of the Antibody Mediated Prevention (AMP) trials
Authors: Huang Yunda , Naidoo Logashvari , Zhang Lily , Carpp Lindsay N. , Rudnicki Erika , Randhawa April , Gonzales Pedro , McDermott Adrian , Ledgerwood Julie , Lorenzo Margarita M. Gomez , Burns David , DeCamp Allan , Juraska Michal , Mascola John , Edupuganti Srilatha , Mgodi Nyaradzo , Cohen Myron , Corey Larry , Andrew Philip , Karuna Shelly , Gilbert Peter B. , Mngadi Kathryn , Lazarus Erica 
Published: September 2020

SummaryThe phase 2b AMP trials are testing whether the broadly neutralizing antibody VRC01 prevents HIV-1 infection in two cohorts: women in sub-Saharan Africa, and men and transgender persons who have sex with men (MSM/TG) in the Americas and Switzerland. We used nonlinear mixed effects modeling of longitudinal serum VRC01 concentrations to characterize pharmacokinetics and predict HIV-1 neutralization coverage. We found that body weight significantly influenced clearance, and that the mean peripheral volume of distribution, steady state volume of distribution, elimination half-life, and accumulation ratio were significantly higher in MSM/TG than in women. Neutralization coverage was predicted to be higher in the first (versus second) half of a given 8-week infusion interval, and appeared to be higher in MSM/TG than in women overall. Study cohort differences in pharmacokinetics and neutralization coverage provide insights for interpreting the AMP results and for investigating how VRC01 concentration and neutralization correlate with HIV incidence.
Pooling saliva to increase SARS-CoV-2 testing capacity
Authors: Watkins Anne E. , Fenichel Eli P. , Weinberger Daniel M. , Vogels Chantal B.F. , Brackney Doug E. , Casanovas-Massana Arnau , Campbell Melissa , Fournier John , Bermejo Santos , Datta Rupak ,   the Yale IMPACT Research Team, Dela Cruz Charles S. , Farhadian Shelli F. , Iwasaki Akiko , Ko Albert I. , Grubaugh Nathan D. , Wyllie Anne L. 
Published: September 2020

AbstractExpanding testing capabilities is integral to managing the further spread of SARS-CoV-2 and developing reopening strategies, particularly in regards to identifying and isolating asymptomatic and pre-symptomatic individuals. Central to meeting testing demands are specimens that can be easily and reliably collected and laboratory capacity to rapidly ramp up to scale. We and others have demonstrated that high and consistent levels of SARS-CoV-2 RNA can be detected in saliva from COVID-19 inpatients, outpatients, and asymptomatic individuals. As saliva collection is non-invasive, extending this strategy to test pooled saliva samples from multiple individuals could thus provide a simple method to expand testing capacity.However, hesitation towards pooled sample testing arises due to the dilution of positive samples, potentially shifting weakly positive samples below the detection limit for SARS-CoV-2 and thereby decreasing the sensitivity. Here, we investigated the potential of pooling saliva samples by 5, 10, and 20 samples prior to RNA extraction and RT-qPCR detection of SARS-CoV-2. Based on samples tested, we conservatively estimated a reduction of 7.41%, 11.11%, and 14.81% sensitivity, for each of the pool sizes, respectively. Using these estimates we modeled anticipated changes in RT-qPCR cycle threshold to show the practical impact of pooling on results of SARS-CoV-2 testing. In tested populations with greater than 3% prevalence, testing samples in pools of 5 requires the least overall number of tests. Below 1% however, pools of 10 or 20 are more beneficial and likely more supportive of ongoing surveillance strategies.
Development and validation of a multiplex bead based assay for the detection of antibodies directed against SARS-CoV-2 proteins
Authors: Bray Robert A. , Lee Jar-How , Brescia Peter , Kumar Deepali , Nong Thoa , Shih Remi , Woodle E. Steve , Maltzman Jonathan S. , Gebel Howard M. 
Published: September 2020

AbstractTransplant recipients who develop COVID-19 may be at increased risk for morbidity and mortality. Determining antibody status against SARS-CoV-2 in candidates and recipients will be important to understand the epidemiology and clinical course of COVID-19 infection in this population. There are multiple antibody tests to detect antibodies to SARS-CoV-2, but their performance varies according to their platforms and the antigenic targets, making interpretation of the results challenging. Additionally, currently available serological tests do not exclude the possibility that positive responses are due to cross reactive antibodies to community coronaviruses. This study describes the development and validation of a high throughput multiplex bead based antibody detection assay with the capacity to identify, simultaneously, patient responses to five distinct SARS-CoV-2 proteins. The antibody response to these proteins are SARS-CoV-2 specific as antibodies against four community coronaviruses do not cross-react. Assay configuration is essentially identical to the single antigen bead assays used in the majority of histocompatibility laboratories around the world and could easily be implemented into routine screening of transplant candidates and recipients. This new assay provides a novel tool to interrogate the spectrum of immune responses to SAR-CoV-2 and is uniquely suitable for use in the transplant setting.
Onset of effects of non-pharmaceutical interventions on COVID-19 worldwide
Authors: Zeilinger Elisabeth L. , Nader Ingo W. , Jomar Dana , Zauchner Clemens 
Published: September 2020

AbstractDuring the initial phase of the global COVID-19 outbreak, most countries responded with non-pharmaceutical interventions (NPIs). The effectiveness of these NPIs has been investigated with simulation studies, that rely on assumptions and by empirical studies with few countries and controversial results. However, it has not been investigated in detail how long different NPIs need to be in place to take effect, or how long they should be in place for their maximum effect to unfold. We used global data and a non-parametric machine learning model to estimate the effects of NPIs in relation to how long they have been in place. Here we show that closure and regulation of schools was the most important NPI, associated with a pronounced effect about 10 days after implementation. Restrictions of mass gatherings and restrictions and regulations of businesses were found to have a more gradual effect, and social distancing was associated with a delayed effect starting about 18 days after implementation. Generally, effects increased until about 40 to 50 days after implementation. Our results can inform political decisions regarding the choice of NPIs and how long they need to be in place to take effect.
The role of masks in reducing the risk of new waves of COVID-19 in low transmission settings: a modeling study
Authors: Stuart RM , Abeysuriya Romesh G , Kerr Cliff C , Mistry Dina , Klein Daniel J , Gray Richard , Hellard Margaret , Scott Nick 
Published: September 2020

AbstractObjectivesTo evaluate the risk of a new wave of coronavirus disease 2019 (COVID-19) in a setting with ongoing low transmission, high mobility, and an effective test-and-trace system, under different assumptions about mask uptake.DesignWe used a stochastic agent-based microsimulation model to create multiple simulations of possible epidemic trajectories that could eventuate over a five-week period following prolonged low levels of community transmission.SettingWe calibrated the model to the epidemiological and policy environment in New South Wales, Australia, at the end of August 2020.ParticipantsNoneInterventionFrom September 1, 2020, we ran the stochastic model with the same initial conditions(i.e., those prevailing at August 31, 2020), and analyzed the outputs of the model to determine the probability of exceeding a given number of new diagnoses and active cases within five weeks, under three assumptions about future mask usage: a baseline scenario of 30% uptake, a scenario assuming no mask usage, and a scenario assuming mandatory mask usage with near-universal uptake (95%).Main outcome measureProbability of exceeding a given number of new diagnoses and active cases within five weeks.ResultsThe policy environment at the end of August is sufficient to slow the rate of epidemic growth, but may not stop the epidemic from growing: we estimate a 20% chance that NSW will be diagnosing at least 50 new cases per day within five weeks from the date of this analysis. Mandatory mask usage would reduce this to 6–9%.ConclusionsMandating the use of masks in community settings would significantly reduce the risk of epidemic resurgence.
Systematic review and meta-analysis of veterinary-related occupational exposures to hazards
Authors: Adebowale OO , Fasanmi OG , Awosile B.B , Afolabi MO , Fasina FO 
Published: September 2020

ABSTRACTObjectiveUnderstanding hazards within the veterinary profession is critical for developing strategies to ensure health and safety in the work environment. This study was conducted to systematically review and synthesize data on reported risks within veterinary workplaces.MethodsA systematic review of published data reporting occupational hazards and associated risk factors were searched within three database platforms namely PubMed, Ebscohost, and Google scholar. To determine the proportion estimates of hazards and pooled odds ratio, two random-effects meta-analysis were performed.ResultsData showed veterinarians and students were at high risk of exposure to diverse physical, chemical, and biological hazards. For the biological, chemical and physical hazards, the pooled proportion estimates were 17% (95% CI: 15.0–19.0, p < 0.001), 7.0% (95% CI: 6.0–9.0%, p < 0.001) and 65.0% (95% CI: 39.0–91.0%, p < 0.001) respectively. A pooled odds ratio indicated the odds of physical (OR = 1.012, 95% CI: 1.008–1.017, p < 0.001) and biological exposures (OR = 2.07, 95% CI: 1.70–2.52, p < 0.001) increased more when working with or in contact with animals than non-contact.ConclusionsThis review has provided a better understanding of occupational health and safety status of veterinarians and gaps within the developing countries. Veterinarians including students are at considerable risk of occupational-related hazards. The need to improve government and organisation policies and measures on occupational health and safety is therefore crucial, most importantly in Africa.
Revealing the extent of the COVID-19 pandemic in Kenya based on serological and PCR-test data
Authors: Ojal John , Brand Samuel P. C. , Were Vincent , Okiro Emelda A , Kombe Ivy K , Mburu Caroline , Aziza Rabia , Ogero Morris , Agweyu Ambrose , Warimwe George M , Uyoga Sophie , Adetifa Ifedayo M O , Scott J Anthony G , Otieno Edward , Ochola-Oyier Lynette I , Agoti Charles N , Kasera Kadondi , Amoth Patrick , Mwangangi Mercy , Aman Rashid , Ng’ang’a Wangari , Tsofa Benjamin , Bejon Philip , Barasa Edwine , Keeling Matt. J. , Nokes D. James. 
Published: September 2020

AbstractPolicy makers in Africa need robust estimates of the current and future spread of SARS-CoV-2. Data suitable for this purpose are scant. We used national surveillance PCR test, serological survey and mobility data to develop and fit a county-specific transmission model for Kenya. We estimate that the SARS-CoV-2 pandemic peaked before the end of July 2020 in the major urban counties, with 34 - 41% of residents infected, and will peak elsewhere in the country within 2-3 months. Despite this penetration, reported severe cases and deaths are low. Our analysis suggests the COVID-19 disease burden in Kenya may be far less than initially feared. A similar scenario across sub-Saharan Africa would have implications for balancing the consequences of restrictions with those of COVID-19.