Investigations into the relationship between behavioural tendencies and social status using the signal crayfish Pacifastacus leniusculus as a model organism

Many studies have shown that animals from a variety of taxa display behavioural tendencies which differ between individuals. If such tendencies are consistent over time and across contexts, they are generally referred to as personalities, temperaments or coping styles. Social conflict is believed to be one of the main factors leading to the evolution of animal personalities. Social conflict may favour the adoption of alternative behavioural options by individuals within a population, thus leading to differing personalities. In many animals, competition for resources leads to the establishment of social hierarchies, through agonistic encounters between conspecifics. Using the signal crayfish (Pacifastacus leniusculus) as a model organism this study investigated if crayfish of differing social status display different behavioural tendencies. To this end size-matched dominant and subordinate individuals were tested for boldness and activity at different time points. The behaviour was tested one day before, immediately after, one day after and six days after an agonistic encounter, in order to test whether crayfish display behavioural tendencies which are consistent over time and expressed in different behaviours and to determine whether pre-existing behavioural tendencies predispose individuals to a certain social status or only emerge as a result of status acquisition. The results show dominant and subordinate individuals differed significantly in their defensive behaviour. Subordinates also showed a high degree of consistency in their response to a predatory stimulus but dominants showed no consistency. In addition there was a negative correlation between the amount of low-offensive behaviour displayed during the agonistic encounter and the response to the predatory stimulus during the behavioural trials. Individuals which showed more low-offensive behaviour showed a weaker response to the predatory stimulus. Furthermore, individuals which showed more high offensive behaviour during the agonistic encounter had also spent more time walking on the day prior to the encounter

Automated, miniaturized, and scalable screening of healthcare workers, first responders, and students for SARS-CoV-2 in San Diego County

Background Successful containment strategies for SARS-CoV-2, the causative virus of the COVID-19 pandemic, have involved widespread population testing that identifies infections early and enables rapid contact tracing. In this study, we developed a rapid and inexpensive RT- qPCR testing pipeline for population-level SARS-CoV-2 detection, and used this pipeline to establish a clinical laboratory dedicated to COVID-19 testing at the University of California San Diego (UCSD) with a processing capacity of 6,000 samples per day and next-day result turnaround times. Methods and findings Using this pipeline, we screened 6,786 healthcare workers and first responders, and 21,220 students, faculty, and staff from UCSD. Additionally, we screened 6,031 preschool-grade 12 students and staff from public and private schools across San Diego County that remained fully or partially open for in-person teaching during the pandemic. Between April 17, 2020 and February 5, 2021, participants provided 161,582 nasal swabs that were tested for the presence of SARS-CoV-2. Overall, 752 positive tests were obtained, yielding a test positivity rate of 0.47%. While the presence of symptoms was significantly correlated with higher viral load, most of the COVID-19 positive participants who participated in symptom surveys were asymptomatic at the time of testing. The positivity rate among preschool-grade 12 schools that remained open for in-person teaching was similar to the positivity rate at UCSD and lower than that of San Diego County, with the children in private schools being less likely to test positive than the adults at these schools. Conclusions Most schools across the United States have been closed for in-person learning for much of the 2020-2021 school year, and their safe reopening is a national priority. However, as there are no vaccines against SARS-CoV-2 currently available to the majority of school-aged children, the traditional strategies of mandatory masking, physical distancing, and repeated viral testing of students and staff remain key components of risk mitigation in these settings. The data presented here suggest that the safety measures and repeated testing actions taken by participating healthcare and educational facilities were effective in preventing outbreaks, and that a similar combination of risk-mitigation strategies and repeated testing may be successfully adopted by other healthcare and educational systems

Firefly: The Case for a Holistic Understanding of the Global Structure and Dynamics of the Sun and the Heliosphere

This white paper is on the HMCS Firefly mission concept study. Firefly focuses on the global structure and dynamics of the Sun's interior, the generation of solar magnetic fields, the deciphering of the solar cycle, the conditions leading to the explosive activity, and the structure and dynamics of the corona as it drives the heliosphere