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BackgroundSignificant uncertainty has existed about the safety of reopening college and university campuses before the COVID-19 pandemic is better controlled. Moreover, little is known about the effects that on-campus students may have on local higher-risk communities. ObjectiveWe aimed to estimate the range of potential community and campus COVID-19 exposures, infections, and mortality under various university reopening plans and uncertainties. MethodsWe developed campus-only, community-only, and campus × community epidemic differential equations and agent-based models, with inputs estimated via published and grey literature, expert opinion, and parameter search algorithms. Campus opening plans (spanning fully open, hybrid, and fully virtual approaches) were identified from websites and publications. Additional student and community exposures, infections, and mortality over 16-week semesters were estimated under each scenario, with 10% trimmed medians, standard deviations, and probability intervals computed to omit extreme outliers. Sensitivity analyses were conducted to inform potential effective interventions. ResultsPredicted 16-week campus and additional community exposures, infections, and mortality for the base case with no precautions (or negligible compliance) varied significantly from their medians (4- to 10-fold). Over 5% of on-campus students were infected after a mean of 76 (SD 17) days, with the greatest increase (first inflection point) occurring on average on day 84 (SD 10.2 days) of the semester and with total additional community exposures, infections, and mortality ranging from 1-187, 13-820, and 1-21 per 10,000 residents, respectively. Reopening precautions reduced infections by 24%-26% and mortality by 36%-50% in both populations. Beyond campus and community reproductive numbers, sensitivity analysis indicated no dominant factors that interventions could primarily target to reduce the magnitude and variability in outcomes, suggesting the importance of comprehensive public health measures and surveillance. ConclusionsCommunity and campus COVID-19 exposures, infections, and mortality resulting from reopening campuses are highly unpredictable regardless of precautions. Public health implications include the need for effective surveillance and flexible campus operations.

The brown ghost knifefish (Apteronotus leptorhynchus (Ellis in Eigenmann, 1912)) is the only vertebrate organism identified thus far that exhibits negligible brain senescence. The present study examines the basic growth patterns of this species, testing the hypothesis that indeterminate growth and lack of reproductive senescence correlate with negligible senescence. Analysis of length-mass relationships revealed negative allometric growth in males and isometric growth in females. Total length at first sexual maturity was 13.5 cm in males and 12.0 cm in females, whereas gonadal mass was 0.02 g in males and 0.2 g in females. Modelling of total length as a function of the number of otolith rings using attenuating growth equations revealed that lengths of up to 26.8 cm in males and 20.2 cm in females can be reached, indicating that the fish continue to grow throughout life. Gonadal mass increased significantly with age in sexually immature individuals of both sexes. In sexually mature fish, gonadal mass showed a marginal increase with age in males and no change in females. The demonstration of indeterminate growth of the fish and of the lack of gonadal regression with age has important implications for the characterization of brown ghost knifefish as a model of negligible senescence. Key words: adult neurogenesis, Apteronotus leptorhynchus, brown ghost knifefish, indeterminate growth, length-mass relationship, negligible senescence, growth curve. Le poisson-couteau brun (Apteronotus leptorhynchus (Ellis in Eigenmann, 1912)) est le seul organisme vertebre identifie a ce jour qui presente une senescence negligeable du cerveau. L'etude se penche sur les motifs de croissance de base de cette espece afin de verifier l'hypothese voulant que la croissance indeterminee et l'absence de senescence reproductrice soient correlees a une senescence negligeable. L'yse des relations longueur-masse a revele une croissance allometrique negative chez les males et une croissance isometrique chez les femelles. La longueur totale a l'atteinte de la maturite sexuelle etait de 13,5 cm pour les males et de 12,0 cm pour les femelles, alors que la masse des gonades etait de 0,02 g pour les males et de 0,2 g pour les femelles. La modelisation de la longueur totale en fonction du nombre d'anneaux d'otolithe a l'aide d'equations d'attenuation de la croissance a revele que des longueurs de jusqu'a 26,8 cm pour les males et 20,2 cm pour les femelles peuvent etre atteintes, ce qui indique que les poissons continuent de croitre tout au long de leur vie. La masse des gonades augmentait de maniere significative avec l'age chez les individus sexuellement immatures des deux sexes. Chez les poissons sexuellement matures, la masse des gonades presentait une augmentation marginale avec l'age chez les males et aucun changement chez les femelles. La demonstration de la croissance indeterminee de ces poissons et l'absence de regression des gonades avec l'age ont d'importantes consequences en ce qui concerne la caracterisation du poisson-couteau brun en tant que modele de senescence egligeable. [Traduit par la Redaction] Mots-cles : neurogenese adulte, Apteronotus leptorhynchus, poisson-couteau brun, croissance indeterminee, relation longueurmasse, senescence negligeable, courbe de croissance., Introduction Across all organisms, senescence manifests itself in a large variety of forms. Based on a comprehensive comparative analysis of this phenomenon, Finch (1990) suggested characterizing this variability in senescence [...]

The article surveys the main notions regarding electromagnetic compatibility of JTRS-type systems: electromagnetic compatibility (EMC) specific terms, influence areas of disturbing factors, parameters. Another section identifies natural and artificial perturbations which can occur in the outdoor spaces the JTRS equipment is used in. A similar analysis is performed for indoor spaces, where perturbations occur due to the materials out of which the equipment is fabricated and the processing of the signal at different blocks. The last section identifies the conditions favouring the occurrence of radiofrequency interferences when collocating JTRS equipment. [ABSTRACT FROM AUTHOR]

Background: Significant uncertainty exists in many countries about the safety of, and best strategies for, reopening college and university campuses until the Covid-19 pandemic is better controlled. Little also is known about the effects on-campus students may have on local higher-risk communities. We aimed to estimate potential community and campus Covid-19 exposures, infections, and mortality due to various university reopening and precaution plans under current ranges of assumptions and uncertainties., Methods: We developed and calibrated campus-only, community-only, and campus-x-community epidemic differential equation and agent-based models. Input parameters for campus and surrounding communities were estimated via published and grey literature, scenario development, expert opinion, accuracy optimization algorithms, and Monte Carlo simulation; models were cross-validated against each other using February-June 2020 data from heterogeneous U.S. counties and states. Campus opening plans (spanning various fully open, hybrid, and fully virtual approaches) were identified from websites and publications. All scenarios were simulated assuming 16-week semesters and estimated ranges for Covid-19 prevalence among community residents and arriving students, precaution compliance, contact frequency, virus attack rates, and tracing and isolation effectiveness. Additional student and community exposures, infections, and mortality were estimated under each scenario, with 10% trimmed medians, standard deviations, and probability intervals computed to omit extreme outlier scenarios. Factorial analyses were conducted to identify intervention inputs with largest and smallest effects., Results: As a base case with no precautions (or no compliance), predicted 16-week student infections and mortality under normal operations ranged significantly from 471 to 9,495 (median: 2,286, SD: 2,627) and 0 to 123 (median: 9, SD: 14) per 10,000 students, respectively. The maximum active exposures across a semester was 15.76% of all students warranting tracing. Total additional community exposures, infections, and mortality ranged from 1 to 187, 13 to 820, and 1 to 21 per 10,000 residents, respectively. 1% and 5% of on-campus students were infected after a mean (SD) of 11 (3) and 76 (17) days, respectively; >10% students infected by the end of a semester in 34.8% of scenarios, with the greatest increase (first inflection point) occurring on aver-age on day 84 (SD: 10.2 days). Common reopening precautions reduced infections by 24% to 26% and mortality by 36% to 50% in both populations. Uncertainties in many factors, however, produced tremendous variability in all results, ranging from medians by -67% to +342%., Conclusions: Consequences on community and student Covid-19 exposures, infections, and mortality of reopening physical campuses are very highly unpredictable, depending on a combination of random chance, controllable (e.g. physical layouts), and uncontrollable (e.g. human behavior) factors. Implications include needs for criteria to adapt campus operations mid-semester, methods to detect when necessary, and contingency plans for doing so.

Sexually dimorphic behaviors develop under the influence of sex steroids, which induce reversible changes in the underlying neural network of the brain. However, little is known about the proteins that mediate these activational effects of sex steroids. Here, we used a proteomics approach for large-scale identification of proteins involved in the development of a sexually dimorphic behavior, the electric organ discharge of brown ghost knifefish, Apteronotus leptorhynchus. In this weakly electric fish, the discharge frequency is controlled by the medullary pacemaker nucleus and is higher in males than in females. After lowering the discharge frequency by chronic administration of β-estradiol, 2-dimensional difference gel electrophoresis revealed 62 proteins spots in tissue samples from the pacemaker nucleus that exhibited significant changes in abundance of >1.5-fold. The 20 identified protein spots indicated, among others, a potential involvement of astrocytes in the establishment of the behavioral dimorphism. Indeed, immunohistochemical analysis demonstrated higher expression of the astrocytic marker protein GFAP and increased gap-junction coupling between astrocytes in females compared with males. We hypothesize that changes in the size of the glial syncytium, glial coupling, and/or number of glia-specific potassium channels lead to alterations in the firing frequency of the pacemaker nucleus via a mechanism mediating the uptake of extracellular potassium ions from the extracellular space.