Scopolamine induces deficits in spontaneous object-location recognition and fear-learning in marmoset monkeys

The non-selective muscarinic receptor antagonist scopolamine (SCP) induces memory deficits in both animals and humans. However, few studies have assessed the effects of amnesic agents on memory functions of marmosets – a small-bodied neotropical primate that is becoming increasingly used as a translational model for several neuropathologies. Here we assessed the effects of an acute SCP administration (0.03 mg/kg, sc) on the behavior of adult marmoset monkeys in two tasks. In the spontaneous object-location (SOL) recognition task, two identical neutral stimuli were explored on the sample trial, after which preferential exploration of the displaced versus the stationary object was analyzed on the test trial. In the fear-motivated behavior (FMB) procedure, the same subjects were submitted to an initial baseline trial, followed by an exposure period to a snake model and lastly a post-exposure trial. All trials and inter-trial intervals lasted 10 min for both tests. Results showed that on the SOL test trial, the saline group explored the displaced object significantly longer than its identical stationary counterpart, whereas SCP-treated marmosets explored both objects equivalently. In the FMB test, the saline group – but not the SCP-treated animals – spent significantly less time where the stimulus had been specifically encountered and more time being vigilant of their surroundings, compared to pre-exposure levels. Drug-related effects on general activity, overall exploration (SOL task) and behavioral response to the aversive stimulus (FMB task) were not observed. SCP thus impaired the marmosets’ short-term ability to detect changes associated with the spatial location of ethologically irrelevant (SOL task) and relevant stimuli (FMB task). Similar results have been reported in other animal species. Marmosets may thus help reduce the translational gap between pre-clinical studies and memory-associated human pathologies

The presence of White students and the emergence of Black-White within-school inequalities: two interaction-based mechanisms

This article investigates mechanism-based explanations for a well-known empirical pattern in sociology of education, namely, that Black-White unequal access to school resources -- defined as advanced coursework -- is the highest in racially diverse and majority-White schools. Through an empirically calibrated and validated agent-based model, this study explores the dynamics of two qualitatively informed mechanisms, showing (1) that we have reason to believe that the presence of White students in school can influence the emergence of Black-White advanced enrollment disparities and (2) that such influence can represent another possible explanation for the macro-level pattern of interest. Results contribute to current scholarly accounts of within-school inequalities, shedding light into policy strategies to improve the educational experiences of Black students in racially integrated settings

Adjusting for academic preparedness when estimating enrollment disparities in advanced high school coursework

Whether racial disparities in enrollment in advanced high school coursework can be attributed to differences in prior academic preparation is a central empirical question in sociological research, with important implications for education policy. However, the regression-based approaches to this question that are predominant in the literature suffer significant methodological limitations by implicitly assuming that students are similarly prepared if and only if they have similar values on a selected set of academic background measures. Here, we provide a general technique to estimate enrollment disparities in advanced coursework between similarly-prepared students of different races that is less vulnerable to these limitations. We introduce a novel measure of academic preparedness, a student's ex-ante probability of "success" in the course, directly adjust for this single measure in a regression model of enrollment on race, and assess the robustness of estimated disparities to potential unmeasured confounding. We illustrate this approach by analyzing Black-White disparities in AP mathematics enrollment in a large, urban, public school system in the United States. We find that preexisting differences in academic preparation do not fully explain the under-representation of Black students relative to White students in AP mathematics, and contrast our results with those from traditional approaches

Unveiling time in dose-response models to infer host susceptibility to pathogens

The biological effects of interventions to control infectious diseases typically depend on the intensity of pathogen challenge. As much as the levels of natural pathogen circulation vary over time and geographical location, the development of invariant efficacy measures is of major importance, even if only indirectly inferrable. Here a method is introduced to assess host susceptibility to pathogens, and applied to a detailed dataset generated by challenging groups of insect hosts (Drosophila melanogaster) with a range of pathogen (Drosophila C Virus) doses and recording survival over time. The experiment was replicated for flies carrying the Wolbachia symbiont, which is known to reduce host susceptibility to viral infections. The entire dataset is fitted by a novel quantitative framework that significantly extends classical methods for microbial risk assessment and provides accurate distributions of symbiont-induced protection. More generally, our data-driven modeling procedure provides novel insights for study design and analyses to assess interventions

Surface characterization of photodegraded poly(ethylene terephthalate). The effect of ultraviolet absorbers

Abstract The surface characterization of photodegraded poly(ethylene terephthalate) was investigated. Films obtained by bi-axial extrusion were exposed in a laboratory weathering chamber for periods of up to , 1100 h of irradiation. Samples prepared with and without an ultraviolet (UV) absorber were tested by infrared, UV -visible and fluorescence spectroscopy. The results indicated that the unstabilized films are very susceptible to the degradation effects causing a large deterioration, especially in surface layers. The presence of an ultraviolet light absorber effectively reduced the formation of carboxyl end-groups at the surface as well as in the bulk of the films. In the case of samples with UV absorber the fluorescence data showed a barrier imposed by this additive in the formation of the monohydroxy-terephthalate. Scanning electron microcopy of fracture surfaces showed that film ductility is highly reduced after exposure.

Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold

Individual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as “frailty variation”. Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic

Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold

Funding Information: We thank Jorge Carneiro, Ben Cooper, José Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio Montalbán, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G., on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil. Funding Information: We thank Jorge Carneiro, Ben Cooper, Jos? Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio Montalb?n, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G. on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico, Brazil. Publisher Copyright: © 2022 Elsevier LtdIndividual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as “frailty variation”. Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic.publishersversionpublishe

Reply to: “Enhancement of Aedes aegypti susceptibility to dengue by Wolbachia is not supported”

Replying to Ant et al. Nature Communications https://doi.org/10.1038/s41467-020-19830-6 (2020

Cladosporium tenuissimum URM 7803: a promising new β-galactosidase producer

The Cladosporium genus, defined by Link in 1816, is one of the largest and most heterogeneous Hyphomycetes genus. It comprises more than 189 species still rarely explored biotechnologically. One of the most studied microbial enzymes, -galactosidase is a glycoside hydrolase enzyme that catalyzes the hydrolysis of -galactosides into monosaccharides through the breaking of a glycosidic bond. Recently, new studies comprising new microbial sources of -galactosidase, presenting biotechnologically interesting characteristics, have been encouraged. In this context, the present study evaluated the production of -galactosidase by a new isolate of Cladosporium tenuissimum. A C. tenuissimum inoculum was prepared adding 107 spore/mL in sterile saline solution 0.85% (w/v) NaCl containing 0.01% (w/v) Tween 80 and added to fermentation medium for enzyme production. The fermentation medium, composed of (% w/v): lactose (2), peptone (0.4), yeast extract (0.4) and salts (KH2PO4 (0.2), Na2HPO4.12H2O (0.8) and MgSO4.7H2O (0.025), pH 6.5, was maintained at 28° C and 180 rpm for 13 days. One sample (50 mL erlenmeyer) was removed every 24 hours and -galactosidase activity was evaluated using ONPG (ortho-Nitrophenyl--galactoside) method. The results showed maximum -galactosidase production by C. tenuissimum URM 7803 on thirteenth day, displayed enzymatic activity of 462.13 U/mL. The C. tenuissimum URM 7803 isolate proved to be a powerful new -galactosidase producer with potential application for food processing.info:eu-repo/semantics/publishedVersio

Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold

Individual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as "frailty variation". Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic