Development work leading to emittance-compensated symmetric emittance and asymmetric emittance RF photoinjectors is discussed. A mature design for a symmetric emittance photoinjector is described, and current work leading to an asymmetric design is detailed. An experimental program to characterize both injectors and to explore the physical mechanism of emittance compensation using the facilitie...

This review article aims to anatomize sources of the healthy worker effect (HWE) and to summarize advantages and limitations of several approaches frequently proposed to eliminate the HWE. Although the HWE is frequently addressed in the context of selection bias, our review suggests that the selection of occupational cohorts with advantageous health status would preferably be addressed as a sou...

BACKGROUND Melissococcus plutonius is an entomopathogenic bacterium that causes European foulbrood (EFB), a honeybee (Apis mellifera L.) disease that necessitates quarantine in some countries. In Czechia, positive evidence of EFB was absent for almost 40 years, until an outbreak in the Krkonose Mountains National Park in 2015. This occurrence of EFB gave us the opportunity to study the epizooti...

It is known that micro-task worker performance fluctuates. While between-worker variability has been studied and has been used to define filters (e.g., to filter out “bad” workers), within-worker variability (i.e. how each worker's performance varies over time) has received less attention. Better understanding of the sources of such variability will result in the design of better filters, and m...

We consider a frictional labor market in which firms want to insure their senior employees against income fluctuations and, at the same time, want to recruit new employees to fill their vacant positions. Firms can commit to a wage schedule, i.e. a schedule that specifies the wage paid by the firm to its employees as function of their tenure and other observables. However, firms cannot commit to...

background influenza is a world-wide public health concern. it is one of the most important viral causes of acute respiratory illness, affecting all age groups, recurring several times during a lifetime. we assessed the antibody titers after vaccination against influenza among hiv-infected patients and health care workers (hcws). patients and methods during this before-after study, the antibody...

Body mass shapes processes from cell metabolism to community dynamics. Little is known, however, about how the average body mass of individuals varies among ecological communities. Ants alter colony mass by independently changing worker mass and/or worker number. In a survey of 49 ecosystems from tundra to tropical rainforest, average worker mass and worker number were uncorrelated (r(s) = 0.2,...