When work is wanted after hours: Testing weekly stress of information communication technology demands using boundary theory

Information communication technologies (ICTs; e.g., smartphones) enable employees to work anywhere and anytime, blurring work and family boundaries. Building on this trend, this study draws from work–family border/boundary theory to examine antecedents and consequences of employees' weekly experiences of ICT demands (i.e., being accessible and contacted for work after hours via ICTs). A sample of 546 elementary teachers completed a registration survey and a weekly diary for 5 weeks. Multilevel modeling results suggest that ICT demands as a form of work intrusion in the home can constitute a source of significant weekly strain (i.e., negative rumination, negative affect, and insomnia). As border crossers, teachers' adoption of a technological boundary tactic (i.e., keeping work email alerts turned off on mobile phones) was related to lower weekly ICT demands. As important border keepers at work, school principals' work–family support was related to teachers' lower weekly ICT demands, whereas parents' after-hours boundary expectations were related to teachers' higher weekly ICT demands. Moreover, teachers' boundary control was found as a mediating mechanism by which the two border keepers influenced teachers' ICT demands−negative rumination link. That is, teachers who received fewer boundary expectations and/or more work–family support had greater boundary control, which in turn buffered the ICT demands–negative rumination relationship.     

3D QSAR studies of dioxins and dioxin-like compounds using CoMFA and CoMSIA

In the present study we have performed comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) on structurally diverse ligands of Ah (dioxin) receptor to explore the physico-chemical requirements for binding. All CoMFA and CoMSIA models have given q(2) value of more than 0.5 and r(2) value of more than 0.84. The predictive ability of the models was validated by an external test set, which gave satisfactory predictive r(2) values. Best predictions were obtained with CoMFA model of combined modified training set (q(2) = 0.631, r(2) = 0.900), giving predictive residual value = 0.02 log unit for the test compound. Addition of CoMSIA study has elucidated the role of hydrophobicity and hydrogen bonding along with the effect of steric and electrostatic properties revealed by CoMFA. We have suggested a model comprises of four structurally different compounds, which offers a good predictability for various ligands. Our QSAR model is consistent with all previously established QSAR models with less structurally diverse ligands.     

Application of an artificial sea salt solution to determine acute toxicity of herbicides to Proisotoma minuta (Collembola)

The acute toxicity test is described in this experiment where the Collembola species Proisotoma minuta was exposed to herbicides in an artificial sea salt solution for seven days. The salt solution did not prohibit the insects' reproduction system. The seven day LD50 values for trifluralin, pendimethalin, metolachlor, prometryn, paraquat, atrazine, fluometuron, and diuron were 3.48, 10.4, 12.4, 13.0, 23.1, 33.4, 250, and 711 mg L(-1), respectively. A good correlation between toxicity of the compounds and their lipophilicity and vapor pressure was recorded in this study.     

Reproductive dynamics of endeavour prawns, Metapenaeus endeavouri and M. ensis, in Albatross Bay, Gulf of Carpentaria, Australia

 The spawning patterns of two penaeid prawns, Metapenaeus endeavouri (Schmitt) and M. ensis (De Haan), were examined from data collected at 45 stations between March 1986 and March 1992. An index of population fecundity based on the abundance, proportion and fecundity of sexually mature females was used as a measure of spawning output of the prawn stock. The population fecundity index for M. ensis was higher than that for M. endeavouri. The monthly population fecundity index for M. endeavouri varied markedly among years, while that for M. ensis was consistent among years. Spawning of M. endeavouri occurred year-round, while that of M. ensis was concentrated mainly in spring (September to November). For M. endeavouri, a minor spawning, derived from a relatively small number of summer spawners, occurred in the 20 to 30 m offshore waters in summer. In early summer (after May), the major spawning group consisted of large females from the winter-spawning cohort, and the spawning area shifted to depths of 30 to 60 m. In winter (July), the major spawning, derived from the winter-spawning cohort, occurred at depths of 20 to 40 m. For M. ensis, the major spawning, derived from the spring-spawning cohort, was observed in depths <50 m and was concentrated particularly in inshore waters (<20 m) in spring. In autumn, the spawning output was mainly from the autumn-spawning cohort, which comprised but a small number of individuals. In winter, the major spawning group again consisted of the large females from the spring-spawning cohort, and spawning increased in the oceanic waters (>50 m). These results suggest that mature female M. endeavouri and M. ensis move offshore (>40 m) by May and July, respectively, and return to shallow waters (<35 m) in July and November, respectively. The monthly reproduction patterns of both species in the “effective spawning” area showed that the major spawning season for M. endeavouri is August to October and that for M. ensis is September to December. Received: 19 February 1999 / Accepted: 18 June 2000     

Regional measurements of PCDD/PCDF concentrations in Korean atmosphere and comparison with gas-particle partitioning models

The current investigation was aimed at determining the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) in the Korean atmosphere along with their estimation using gas-particle partitioning. Samples collected from six cites showed that large cities were polluted with a concentration of 0.593 pg TEQ/m3. Samples were also collected from residential (nine sites), commercial (five sites), and industrial (seven sites) districts in each city. Higher levels of PCDDs/PCDFs were observed in industrial area than other areas, since it includes many sources. Higher chlorinated 2,3,7,8-substituted congeners were predominantly found in the particulate phase. HpCDD/Fs and OCDD/Fs shared 97-99% of the particulate phase, whereas TCDD/Fs, which dominated the gaseous phase, shared 34.8% and 42.8% in 2,3,7,8-substituted congeners. The regression dataset was transformed due to the relationship between log K(P) and log P(L)o. A wide variation was observed in the slopes for the residential areas when compared with the slopes for the commercial and industrial areas. The Junge-Pankow model and K(oa) adsorption model were both found to be helpful in describing the gas-particle partitioning in the current study.     

Weekly work–school conflict,sleep quality,and fatigue: Recovery self‐efficacy as a cross‐level moderator

This study employed a weekly diary method among a sample of 74 Midwestern college student workers in order to examine the within‐person relationships between work–school conflict, sleep quality, and fatigue over five weeks. Further, recovery self‐efficacy was proposed as a cross‐level moderator of the relation between sleep quality and fatigue. Results from multilevel analyses demonstrated that weekly work–school conflict was negatively related to weekly sleep quality and positively related to end‐of‐week fatigue, with sleep quality partially mediating the relation between work–school conflict and fatigue. These findings enhance understanding of the process by which work–school conflict contributes to college student workers' strain on a weekly basis. Additionally, student workers with low recovery self‐efficacy demonstrated a negative relation between sleep quality and fatigue; however, this relation did not exist for student workers with high recovery self‐efficacy. This finding suggests recovery self‐efficacy as an important resource that may reduce the association between poor sleep quality (as a result of work–school conflict) and fatigue. The current findings provide important theoretical and practical implications for researchers, organizations, and college institutions as a whole. Copyright © 2014 John Wiley & Sons, Ltd.     

Acute and chronic health risk assessment for inhalation and ingestion exposure in acrylic acid leak accidents

Environmental Science and Pollution Research - We established a hypothetical acrylic acid leak accident scenario, conducted a health risk assessment of local residents, and compared an actual...     

Source contributions to fine particulate matter in an urban atmosphere

This paper proposes a practical method for estimating source attribution by using a three-step methodology. The main objective of this study is to explore the use of the three-step methodology for quantifying the source impacts of 24-h PM2.5 particles at an urban site in Seoul, Korea. 12-h PM2.5 samples were collected and analyzed for their elemental composition by ICP-AES/ICP-MS/AAS to generate the source composition profiles. In order to assess the daily average PM2.5 source impacts, 24-h PM2.5 and polycyclic aromatic hydrocarbons (PAH) ambient samples were simultaneously collected at the same site. The PM2.5 particle samples were then analyzed for trace elements. Ionic and carbonaceous species concentrations were measured by ICP-AES/ICP-MS/AAS, IC, and a selective thermal MnO2 oxidation method. The 12-h PM2.5 chemical data was used to estimate possible source signatures using the principal component analysis (PCA) and the absolute principal component scores method followed by the multiple linear regression analysis. The 24-h PM2.5 source categories were extracted with a combination of PM2.5 and some PAH chemical data using the PCA, and their quantitative source contributions were estimated by chemical mass balance (CMB) receptor model using the estimated source profiles and those in the literature. The results of PM2.5 source apportionment using the 12-h derived source composition profiles show that the CMB performance indices; chi2, R2, and percent of mass accounted for are 2.3%, 0.97%, and 100.7%, which are within the target range specified. According to the average PM2.5 source contribution estimate results, motor vehicle exhaust was the major contributor at the sampling site, contributing 26% on average of measured PM2.5 mass (41.8 microg m-3), followed by secondary sulfate (23%) and nitrate (16%), refuse incineration (15%), soil dust (13%), field burning (4%), oil combustion (2.7%), and marine aerosol (1.3%). It can be concluded that quantitative source attribution to PM2.5 in an urban area where source profiles have not been developed can be estimated using the proposed three-step methodology approach.     

Mechanical characteristics evaluation of biogas micro turbine power systems

As the increase of energy demand, the emission of CO2 is also likely to increase by at least the same amount because energy supply will be based on fossil fuels, which is more apparent in a number of developing countries. With the total global energy environment and rapid increase of domestic and foreign demand, renewable energy is the inevitable energy source for the future. In this context, the micro gas turbines (MGTs) by using bio-energy is being considered as a promising solution. In order to develop the real plant system of those technologies such as 60 kW-class micro gas turbine by using swine biogas, we finished the optimal design and construction for a biomass fueled MGT system. This paper consists of 1) MGT system design for swine bio gas 2) material evaluation for bio gas piping 3) computational fluid dynamics analysis for bio gas sulfur removal tower and sulfur absorption filter 4) the fundamental modeling using manufacturer's technical specifications and performance simulation by PEPSE-GT 5) field test and application of bio gas micro gas turbine. Finally, I established to set up the top-notched distributed power system design and optimal application.