Overtime work as the antecedent of employee satisfaction,firm productivity,and innovation

Overtime work has been blamed for the deterioration of employee satisfaction and productivity. However, the organization‐level implications of overtime work as a normative expectation remain unclear. In this study, such effects were analyzed through human capital theory and a causal attribution approach. Various organizational outcomes and boundary conditions were explored in explaining these implications. The analysis of time lagged data from 273 firms affirmed that a firm's overtime level was related negatively to employee satisfaction. However, it was positively related to the firm's productivity and curvilinearly (inverted U‐shaped) related to innovation. The effects of the firm's overtime level on firm productivity and innovation were also moderated by organizational trust. This study highlights the costs and benefits of overtime work as tools for utilizing human capital and reveals the critical contingency of organizational trust that enables firms to attenuate the costs of the overtime level and accentuate its potential benefits.     

Composition and distribution of polycyclic aromatic hydrocarbons in the surface sediments from the Susquehanna River

Polycyclic aromatic hydrocarbon (PAH) concentrations in 34 surface sediments along the Susquehanna River were investigated in 2000. The total concentrations of PAHs in the surface sediments of Lake Clarke, Lake Aldred, the upper Conowingo Reservoir, and the lower Conowingo Reservoir were 3.3+/-1.5 microg g-1 (n=9), 1.6+/-1.3 microg g-1 (n=4), 9.8+/-5.5 microg g-1 (n=7), and 4.0+/-1.2 microg g-1 (n=14), respectively. These represent the first comprehensive measurement of PAHs in Susquehanna River surface sediments. Overall, total PAH concentrations were relatively lower in Lake Aldred, which is more shallow and sloped, and significantly higher in the upper Conowingo Reservoir. The sediment PAH levels were related to river flow rates, which are indirectly correlated with the particle size of the surface sediments. Total PAH levels in all the studied sites were below the effects range median (ERM) of 44.8 microg g-1 with 38% (13 of the 34 sampling sites) exceeding the effects range low (ERL) of 4.02 microg g-1. Principal component analysis indicated that variations in the PAH compound patterns of each reservoir decreased from upstream to downstream, indicating that the surface sediments were mixed along the Susquehanna River. The PAH patterns in the lower Conowingo Reservoir sediments were a combination of those upstream sources. Source analysis using isomer ratios as indicators suggested that PAHs in the Susquehanna River surface sediment are derived from the combustion of fossil fuels such as coal and gasoline with coal as the major source of contaminants.     

Removal of trichloroethylene from soil using the hydration of calcium oxide

Quicklime addition to soil at a remediation site was observed to sufficiently reduce TCE levels, but the cause of the removal could not be confirmed with the field data collected. Potential mechanisms for CaO treatment of trichloroethylene (TCE) in soil include degradation and volatilization. Since earlier studies found TCE degradation to occur during the hydration of CaO under conditions where volatilization was limited, research was conducted on mechanisms of TCE removal from soil by CaO application under conditions where volatilization was allowed to occur. TCE volatilization in soil treated with 0%, 5%, 10%, and 20% CaO doses was measured in experiments where the degree of volatilization could be tracked. The total TCE removal from soil spiked with TCE at CaO doses from 5% to 20% ranged from 97% to 99% of the initial TCE mass. Volatilization accounted for 64.4-92.5% of the TCE removal, with unrecovered TCE and TCE degradation accounting for the remaining fraction. The greater heat encountered with higher CaO doses helped minimize obstacles to TCE volatilization, such as high soil organic and clay content. Treatment with a 20% CaO dose, however, led to the formation of byproducts such as dichloroacetylene. TCE degradation to dichloroacetylene at the 20% CaO dose ranged from 2.7% to 6.4% of the initial TCE. Volatilization was concluded to be the dominant process for TCE removal from soil during CaO treatment.     

MULTIOBJECTWE OPTIMIZATION OF RESERVOIR SYSTEMS OPERATION1

ABSTRACT: Development of optimal operational policies for large-scale reservoir systems is often complicated by a multiplicity of conflicting project uses and purposes. A wide range of multiobjective optimization methods are available for appraising tradeoffs between conificting objectives. The purpose of this study is to provide guidance as to those methods which are best suited to dealing with the challenging large-scale, nonlinear, dynamic, and stochastic characteristics of multireservoir system operations. As a case study, the selected methodologies are applied to the Han River Reservoir System in Korea for four principal project objectives: water supply and low flow augmentation; annual hydropower production, reliable energy generation, and minimization of risk of violating firm water supply requirements. Additional objectives such as flood control are also considered, but are imposed as fixed constraints.     

The seasonal distribution of heavy metals in Mussel sample from Yalova in the Marmara Sea, 2008�C2009

Concentration of the some heavy metals (Co, Cu, Fe, Ni, Pb and Zn) Mediterranean mussel Mytilus galloprovincialis from Yalova (Marmara Sea) were investigated seasonally. The mean concentrations of Co, Cu, Fe, Ni, Pb and Zn in the soft tissues were 4.08 ± 0.67, 5.54 ± 0.59, 156.72 ± 20.18, 3.71 ± 1.14, 2.92 ± 0.51 and 106.23 ± 5.66 mg kg(?-1) dry weights, respectively. There were no significant differences between the metal concentrations among the seasons (P > 0.05). The mean Pb and Zn concentrations were higher than the acceptable limit proposed by International Turkish standards.     

DNA polymorphism and globin chain analysis in the prenatal diagnosis of β-thalassaemia major in Taiwan

Thirty-six pregnancies in 25 families at risk of β-thalassaemia major received prenatal diagnosis. Chorionic villus sampling or amniocentesis was done in 35 pregnancies to obtain fetal cells for DNA linkage study, for which Southern blotting and DNA hybridization were used to detect seven restriction fragment length polymorphisms (RFLPs) within the β-globin gene cluster: ϵ-HincII, ^Gγ-HindIII, ^Aγ-HindIII, Φβ-HincII, 3′Φβ-HincII, β-AvaII, and 3′β BarnHI. β-Thalassaemia major was diagnosed in seven and excluded in 22 pregnancies. In the remaining six cases, β-thalassaemia major could not be excluded. In these six pregnancies and another one with late booking, ultrasound-guided cordocentesis was performed at the 22nd to 27th week of gestation. Globin chain composition was determined with urea-acetic acid-Triton X-100-12 per cent polyacrylamide gel electrophoresis. β-Thalassaemia major was diagnosed in two fetuses and excluded in the other five. Eleven fetuses (in which β-thalassaemia major was excluded) have been delivered and are healthy at more than 5 months old DNA linkage analysis coupled with globin chain electrophoresis provides an effective way for prenatal diagnosis of β-thalassaemia major, although these methods are being replaced by more direct detection techniques using oligonucleotide probes.     

Removal of arsenic in tailings by soil flushing and the remediation process monitoring

In order to investigate the optimum conditions for the application of soil flushing of arsenic, a batch test was carried out using EDTA at various concentration and pH levels. Based on the optimum condition derived from the batch test, a column test was conducted to examine the feasibility of the soil-flushing technology under field-equivalent conditions. In this column test, a low flushing solution flow rate showed a significantly higher As removal efficiency (71.6%) than a high flow rate (56.3%). TCLP (toxicity characteristic leaching procedure) and a seed germination test were carried out to monitor the toxicity both during and after the treatment. The finally treated tailings were shown to be significantly remediated, having a reduced toxicity by both the TCLP and seed germination tests.     

Characteristics of organic precursors and their relationship with disinfection by-products

The molecular weight distribution and chemical composition of precursors and their relationship with disinfection by-products (DBPs) were investigated. Most of the organic matter responsible for the major DBP precursors in the Pan-Hsin water are small compounds with a molecular weight less than 1 kDa. The hydrophobic acids display the greatest ability to produce DBP. Therefore, effective removal of small molecules or hydrophobic acidic organics prior to disinfection process will significantly reduce the DBP concentration in the finished water. Although the coagulation process is effective in removing large organic precursors and the removal efficiencies of CHCl3 formation potential and organic carbon increase proportionally to the molecular weight of the precursors, the conventional treatment methods have limited efficiency in eliminating small precursors, which have high DBP formation potential.     

Investigation of acute toxicity of chlorpyrifos-methyl on guppy Poecilia reticulata

Static bioassays were made to determine acute toxicity of chlorpyrifos-methyl, a wide spectrum organophosphorus insecticide and potential toxic pollutant of aquatic ecosystem, Guppy fish (Poecilia reticulata). Bioassays were made at a regulated temperature of 22+/-1 degrees C and were repeated three times. Lethal doses of the insecticides were determined using LC50 software programme of U.S. EPA based on Finney's Probit Analysis statistical method. The 96 h LC50 value and 95% confidence limit of chlorpyrifos-methyl for Guppy was estimated as 1.79 (1.47-2.10) mg/l. The fish exposed to chlorpyrifos-methyl exhibited behavioral changes in the form of neurotoxin toxicity: less general activity than control group, loss of equilibrium, erratic swimming and staying motionless at a certain location generally at mid-water level for prolonged periods. The 1 mg/l (lowest) concentration had similar behavior (NOEC) with the control group.