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51.
The outbreak of COVID-19 resulted in numerous jurisdictions instituting “shelter-in-place'' orders (SPOs). While designed to restrict or impede normal levels of social proximity, SPOs altered the way or degree to which workers interact with each other and have likely imposed a toll on employee well-being. The authors exploit the temporal and geographic variation in U.S. SPOs to investigate their effect on loneliness among online workers. Variation in loneliness is then linked to worker behavior in a simple two-person, collaborative task (a framed stag hunt). The analysis reveals a strong positive relationship between SPOs and loneliness on average, peaking during the wave associated with the most prolonged duration of isolation. SPOs disproportionately impacted workers in occupations not substantially involving teamwork or collaboration. As reported loneliness increases, the probability of an individual collaborating in a simple interactive workplace scenario decreases significantly. In the final survey wave, SPOs are scarcer, loneliness subsides, and cooperative behavior increases dramatically.  相似文献   
52.
In this study, the local atomic rearrangements caused by thermally induced martensitic phase transitions in Ni-37.5 at.%Al alloy model based on embedded atom method are studied using molecular dynamics simulations. The local atomic orders and defective structural part of the transformed regions are analysed using the bond orientational order parameters, which are employed mainly to diagnose short-range order of liquid state structures, and the radial distribution functions. In addition, short-range order properties in the model alloy were analysed using Honeycutt–Andersen method, which is commonly used to determine the relationship between atomic pairs. The results of our simulations disclosed that the local atomic rearrangement is of great importance to understand the local character of the transformation path from austenite to martensite phase.  相似文献   
53.
A new classification of the branchiopod Crustacea   总被引:16,自引:1,他引:15  
The first satisfactory groupings of the components of the Branchiopoda (Crustacea) were those of G. O. Sars, whose successive refinements, as modified by Caiman in a much used work, received wide acceptance. These schemes, and the more important of the subsequently suggested changes, are listed and tabulated. The Branchiopoda is a morphologically heterogeneous group whose component subgroups share a constellation of primitive features. It is also ancient, with representatives known from as far back as the Devonian, and probably originated in pre-Devonian times, yet still has many extant, sometimes highly successful, representatives. Such a situation presents difficulties to the would-be classifier. A new scheme is proposed which involves the elevation of four lower categories among the so-called Cladocera to ordinal rank. Two conchostracan taxa are also given ordinal status. The ten constituent orders now recognized within the Branchiopoda are defined in more detail than hitherto as a working basis for future investigations.  相似文献   
54.
Heteropteran predators constitute an important component of predatory guilds in terrestrial and aquatic ecosystems. Most heteropteran species have generalist diets, and intraguild predation has been documented in most heteropteran families. Zoophytophagous species also frequently engage in intraguild interactions. An increase in extraguild prey density is often predicted to reduce intraguild predation between guild members by providing abundant alternate prey. However, an increase of extraguild prey density may also be associated with an increase in the density of intraguild predators, which could instead strengthen intraguild predation. Evaluating the combined effect of these potentially opposing influences on intraguild predation is difficult. Most studies have been carried out in the laboratory, using artificially simplified communities of predators and prey and employing spatial and temporal scales that may not reflect field conditions. We review experimental studies examining how extraguild prey density influences the intensity of intraguild predation and then report an observational case study examining the influence of extraguild prey density on the intensity of intraguild predation at larger spatial and temporal scales in unmanipulated cotton fields. Fields with more abundant extraguild prey (aphids, mites) were not associated with elevated densities of intraguild predators, and were strongly associated with increased survival of intraguild prey (lacewing larvae). In this system, the ability of extraguild prey to relax the intensity of intraguild predation, as previously documented in small-scale field experiments, also extends to the larger spatial and temporal scales of commercial agriculture.  相似文献   
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