Complex schooling behaviors result from local interactions among individuals. Yet, how sensory signals from neighbors are analyzed in the visuomotor stream of animals is poorly understood. Here, we ...studied aggregation behavior in larval zebrafish and found that over development larvae transition from overdispersed groups to tight shoals. Using a virtual reality assay, we characterized the algorithms fish use to transform visual inputs from neighbors into movement decisions. We found that young larvae turn away from virtual neighbors by integrating and averaging retina-wide visual occupancy within each eye, and by using a winner-take-all strategy for binocular integration. As fish mature, their responses expand to include attraction to virtual neighbors, which is based on similar algorithms of visual integration. Using model simulations, we show that the observed algorithms accurately predict group structure over development. These findings allow us to make testable predictions regarding the neuronal circuits underlying collective behavior in zebrafish.
COVID-19 hit Italy in February 2020 after its outbreak in China at the beginning of January. Why was Italy first among the Western countries? What are the conditions that made Italy more vulnerable ...and the first target of this disease? What characteristics and diffusion patterns could be highlighted and hypothesized from its outbreak to the end of March 2020, after containment measures, including a national lockdown, were introduced? In this paper, we try to provide some answers to these questions, analyzing the issue from medical, geographical and planning points of view. With reference to the Italian case, we observed the phenomenon in terms of the spatial diffusion process and by observing the relation between the epidemic and various environmental elements. In particular, we started from a hypothesis of the comparable economic, geographical, climatic and environmental conditions of the areas of Wuhan (in the Hubei Province in China, where the epidemic broke out) and the Po Valley area (in Italy) where most cases and deaths were registered. Via an ecological approach, we compared the spatial distribution and pattern of COVID-19-related mortality in Italy with several geographical, environmental and socio-economic variables at a Provincial level, analyzing them by means of spatial analytical techniques such as LISA (Local Indicators of Spatial Association). Possible evidence arose relating to COVID-19 cases and Nitrogen-related pollutants and land take, particularly in the Po Valley area.
The Gulf of California illegal fishery for totoaba (a CITES Appendix I-listed fish species since 1977) has led to socio-ecological degradation. Particularly, this fishery is well known for ...incidentally catching the critically endangered vaquita. However, its impacts on the larger ecosystem are understudied. For decades local experts and non-governmental organizations had reported large amounts of in-use and derelict fishing gear used for totoaba in the Upper Gulf of California (UGoC), but the issued remained unstudied. Six of the co-authors participated directly in gear retrieval efforts and their experience is recorded here. We also performed a literature review to collect a) information on the history, dimension, root causes and impacts of gear discarding practices, and b) lessons drawn from the inter-institutional gear recovery effort performed between 2016 and 2020. For this last objective, we used the Inter-Institutional Gap Framework (IIG). By mapping all institutions involved and their relationships, the IIG allows to identify coordination gaps among multi-level institutions. We found that the gear recovery allowed to bridge historical gaps between formal and informal institutions in the UGoC. The results of the gear recovery effort (9.3 tons of intercepted nets within a section of the UGoC) also helped illustrate the large scope of the problem, which seems to be caused by local oceanographic conditions and the fishers’ need to avoid enforcement. Our study provides a first estimation of the size of this problem and adds to a body of literature on the relationship between illegal fisheries and gear discarding.
Children of farmworkers may be chronically exposed to pesticides via the take-home exposure pathway.
The goal of this review was to analyze scientific literature evaluating the role of the take-home ...pesticide exposure pathway in children of agricultural workers.
A systematic review was undertaken and inclusion criteria were applied to identify original articles of interest. Of the 30 articles included in this review, some belonged to the same studies, resulting in a total of 23 studies. Eight studies assessed environmental samples, nine collected biological samples, and the remaining six analyzed both. Eleven studies compared pesticide levels between farm and non-farm families.
There is convincing evidence that children of farmworkers are exposed to pesticides at higher levels than “non-agricultural” children, even when residing in the same agricultural communities. These levels were shown to depend on the season, occupation, number of farmworkers per home, and type of crops. Other factors such as age, gender and, sex seem to also influence this pathway. Some studies have shown that pesticides used solely in agriculture are found only in households of farmworkers spraying these pesticides. Moreover, intervention studies have shown that behaviors among farmworkers can significantly lower exposure of people living in the same households as farmworkers.
The evidence presented here raises concerns regarding health effects associated with exposure to pesticides in children living in agricultural communities, and indicates that strategies should be developed to reduce exposures in these populations.
•Systematic review of scientific literature on take-home exposure pathway of pesticides.•Role of this pathway in children of agricultural workers.•Convincing evidence that children of farmworkers are exposed through this pathway.
The present work investigates the effect of different outermost connector types on the hydrodynamic responses of a modular multi-purpose floating structure (MMFS) system. The MMFS system is ...preliminarily designed for a mild sea zone, which is composed of a number of standardized floating modules. In this study, the MMFS system has been simplified as a seven-module connected system. Considering the structural deformation of the MMFS system mainly occurs in the connectors among adjacent modules, each module is viewed as a rigid body. Both the hydrodynamic interaction effect and mechanical coupling effect among modules have been taken into consideration in the time-domain analysis. Different outermost connector designs have been proposed and investigated for the MMFS system. The results indicate that the hydrodynamic responses of the MMFS system are sensitive to the effects of the connector types, the wave phase, and the wavelength. The hinge-type design of the outermost connector can significantly reduce the extreme responses of both the bending moment and the shear force of the connectors. The additional PTO damper design for the outermost hinge-type connector can effectively reduce the motion of the outermost module, and also produce considerable wave energy.
•Different outermost connector types can strongly influence the hydrodynamic responses of the MMFS system.•A proper PTO system for the outermost hinge connector, can effectively produce considerable wave energy.•The length-ratio effect on the hydrodynamic responses of the MMFS system has been figured out.•Proper outermost connector design can significantly reduce the extreme responses of the MMFS system.
We examine how directors with investment banking experience affect firms׳ acquisition behavior. We find that firms with investment bankers on the board have a higher probability of making ...acquisitions. Furthermore, acquirers with investment banker directors experience higher announcement returns, pay lower takeover premiums and advisory fees, and exhibit superior long-run performance. Overall, our results suggest that directors with investment banking experience help firms make better acquisitions, both by identifying suitable targets and by reducing the cost of the deals.
A power take-off oil-hydraulic system is designed for an oscillating wave surge converter. The adaptation of the converter to the power take-off is performed with genetic algorithms in order to find ...out the optimal geometrical and control parameters, while different power take-off layout configurations are simulated to maximize their efficiency. The simulations show that the power take-off of the oscillating wave surge converter is more effective and efficient, because the converter is driven by bigger excitation wave moments, rather than the resonant characteristics of the point absorber converter, and on the other hand, allows a less constrained design optimization of the mechanical interface with the power take-off. It was verified that these key features allow the production of lower oil flowrates at higher pressure levels, lower oil flow speeds at the cylinder ports and lower ratios between hydraulic peak and averaged power, thus characteristics that must be found in an efficient and effective power take-off.
•A power take-off oil-hydraulic system is designed for a bottom-hinged flap type wave energy converter.•The adaptation of the converter to the power take-off is performed with genetic algorithms.•The simulations show that the power take-off of the bottom-hinged plate converter is effective and efficient.•The design allowed production of lower oil flowrates at higher pressure levels, lower oil flow speeds at the cylinder ports.•The design allowed also lower ratios between hydraulic peak and averaged power.
The present study investigated effects of cognitive and visual loads on driving performance after take-over request (TOR) in an automated driving task. Participants completed automated driving in a ...driving simulator without a non-driving related task, with an easy non-driving related task, and with a difficult non-driving related task. The primary task was to monitor the environment and the system state. An N-back task and a Surrogate Reference Task (SuRT) were adapted to induce cognitive and visual loads respectively. The system followed a front vehicle automatically. Driving performance was measured by responses to a critical event (appearance of a broken-down car) after the automated system issued TOR and then terminated. High subjective difficulty of the N-back task was related to increased time and increased steering angle variance in the time course from onset of steering control to lane change, while high subjective difficulty of SuRT was related to increased steering angle variance in the time course after lane change. This suggests that both cognitive and visual loads affect driving performance after TOR in automated driving, but the effects appear in different time courses.
•We tested effects of cognitive and visual loads on driving performance after TOR.•Both cognitive and visual loads affected driving performance after TOR.•However, the effects appeared in different time courses.•The results suggest a need to monitor driver's state in automated driving.
Adipose‐derived mesenchymal stem cell (ADSC)‐based regenerative therapies have shown potential for use in many chronic diseases. Aging diminishes stem cell regenerative potential, yet it is unknown ...whether stem cells from aged donors cause adverse effects in recipients. ADSCs can be obtained using minimally invasive approaches and possess low immunogenicity. Nevertheless, we found that transplanting ADSCs from old donors, but not those from young donors, induces physical dysfunction in older recipient mice. Using single‐cell transcriptomic analysis, we identified a naturally occurring senescent cell‐like population in ADSCs primarily from old donors that resembles in vitro‐generated senescent cells with regard to a number of key pathways. Our study reveals a previously unrecognized health concern due to ADSCs from old donors and lays the foundation for a new avenue of research to devise interventions to reduce harmful effects of ADSCs from old donors.
Urban Air Mobility (UAM), a subset of advanced air mobility, is a concept that envisions safe, sustainable, affordable, and accessible air transportation for passenger mobility, cargo delivery, and ...emergency management within or traversing a metropolitan area. In recent years, several companies have designed and tested enabling elements of this concept, including; prototypes of vertical take-off and landing (VTOL) aircraft, operational concepts, and market studies to understand potential business models. While UAM may be enabled by the convergence of several factors, a number of barriers such as weather could present challenges to scaling operations. This research discusses the potential weather and public acceptance challenges for operations in adverse conditions. This article presents a comprehensive seasonal and diurnal climatology analysis using historical observations across anticipated operational altitudes (surface- 5000 ft AGL) at ten metropolitan areas across the United States for the NASA Aeronautics Research Mission Directorate (ARMD). Public perceptions of weather-related societal barriers were evaluated through a five-city general population survey (n = 1,702) where respondents were asked about their views regarding flying in a small aircraft in a variety of adverse weather conditions using a six statement 5-point Likert scale. The results of the climatology analysis found weather most favorable in Los Angeles and San Francisco, with much less favorable conditions in Denver, New York City, and Washington D.C. In the future, equipping automated vehicles, unmanned aircraft systems, and VTOLs with meteorological sensors coupled with machine learning and artificial intelligence could enhance predictive capabilities that reduce flight cancellations and delays for travelers.
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