23,208 research outputs found
Employeesâ Financial Insecurity and Health: The Underlying Role of Stress and WorkâFamily Conflict Appraisals
Data from two longitudinal samples were utilized to elucidate underlying mechanisms of the wellâestablished relationship between financial insecurity and health outcomes, stemming from the theoretical rationale of conservation of resources and cognitive appraisal theories. Study 1 (n = 80) consisted of lowâwage food manufacturing employees working full time, while Study 2 (n = 331) was consisted of a larger, heterogeneous sample of fullâtime workers representing multiple occupations. Respondents were surveyed on financial insecurity, workâtoâfamily conflict (WFC), stress, and health outcomes at two time periods, 3 months apart. Results across our studies provided support for the direct effects of financial insecurity on WFC and stress. In addition, appraisals of WFC and stress serve as significant mediators of the relationship between financial insecurity and health outcomes, including a significant overall lagged effect across time, and perceived stress accounting for the largest proportion of variance in the lagged relationship among Time 1 financial insecurity and Time 2 health outcomes. Besides support for conservation of resources and cognitive appraisal theories, practically, our studies suggest that workplace initiatives to reduce financial insecurity could positively influence employeesâ workâfamily, stress, and health experiences
Modeling of the processing and removal of trace gas and aerosol species by Arctic radiation fogs and comparison with measurements
A Lagrangian radiation fog model is applied to a fog event at Summit, Greenland. The model simulates the formation and dissipation of fog. Included in the model are detailed gas and aqueous phase chemistry, and deposition of chemical species with fog droplets. Model predictions of the gas phase concentrations of H2O2, HCOOH, SO2, and HNO3 as well as the fog fluxes of S(VI), N(V), H2O2, and water are compared with measurements. The predicted fluxes of S(VI), N(V), H2O2, and fog water generally agree with measured values. Model results show that heterogeneous SO2 oxidation contributes to approximately 40% of the flux of S(VI) for the modeled fog event, with the other 60% coming from preexisting sulfate aerosol. The deposition of N(V) with fog includes contributions from HNO3 and NO2 initially present in the air mass. HNO3 directly partitions into the aqueous phase to create N(V), and NO2 forms N(V) through reaction with OH and the nighttime chemistry set of reactions which involves N2O5 and water vapor. PAN contributes to N(V) by gas phase decomposition to NO2, and also by direct aqueous phase decomposition. The quantitative contributions from each path are uncertain since direct measurements of PAN and NO2 are not available for the fog event. The relative contributions are discussed based on realistic ranges of atmospheric concentrations. Model results suggest that in addition to the aqueous phase partitioning of the initial HNO3 present in the air mass, the gas phase decomposition of PAN and subsequent reactions of NO2 with OH as well as nighttime nitrate chemistry may play significant roles in depositing N(V) with fog. If a quasi-liquid layer exists on snow crystals, it is possible that the reactions taking place in fog droplets also occur to some extent in clouds as well as at the snow surface
Multi-mode photonic crystal fibers for VCSEL based data transmission
Quasi error-free 10 Gbit/s data transmission is demonstrated over a novel
type of 50 micron core diameter photonic crystal fiber with as much as 100 m
length. Combined with 850$ nm VCSEL sources, this fiber is an attractive
alternative to graded-index multi-mode fibers for datacom applications. A
comparison to numerical simulations suggests that the high bit-rate may be
partly explained by inter-modal diffusion.Comment: Accepted for Optics Expres
Aerosol production and growth in the marine boundary layer
The dependence of cloud condensation nuclei (CCN) production on the marine dimethylsulfide (DMS) flux is modeled with a dynamic description of the gas, aerosol, and aqueous phase processes in a closed air parcel. The results support the conclusion reached in previous work with a steady state model that an approximately linear dependence exists between CCN concentration and DMS flux under typical remote marine conditions. This linearity does not hold for low DMS fluxes (the threshold is typically near 2.5 ÎŒmol m^(â2) day^(â1)) because the seasalt particles heterogeneously convert the available SO_2 to sulfate inhibiting the creation of new particles. The conditions under which this linear relationship holds are investigated by a series of sensitivity studies, focusing particular attention on the impact of the timing and frequency of cloud events. We consider the regimes of the model's semiempirical parameters, showing that the uncertainty associated with two such parameters, namely, the nucleation rate scaling factor and the sulfuric acid accommodation coefficient, is sufficient to change the predicted CCN production due to DMS from over 300 cm^(â3) day^(â1) to none. This sensitivity accounts for most of the range of results predicted by previous models of the DMS-CCN system
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