5,730 research outputs found

    The Opioid Crisis, Employee Health Capital, and Corporate Information Production

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    This study examines the effect of employee health on corporate information production. Utilizing exposure to opioid abuse as the proxy for employee health, we find that firms headquartered in counties of high opioid prescription rate produce significantly less accurate management earnings forecasts. This result is robust to controlling for other dimensions of human capital and to utilizing the effective anti-opioid legislation across states as a plausibly exogenous variation that limits the prescriptions of opioid. The negative effect of opioid abuse is stronger for firms facing higher forecast difficulty, and is mitigated for firms with easier access to opioid treatment, for firms with superior employee welfare policies, and for firms with a corporate social responsibility (CSR) committee. We also show that managers delay earnings announcements and reduce forecast precision amidst high local opioid activity. Finally, we show that investors react less strongly to news in forecasts issued by firms located in high opioid areas, consistent with their recognition of the potential adverse effect of opioid abuse on information production within the firm

    Purification and biochemical characterization of a serine alkaline protease TC4 from a new isolated Bacillus alcalophilus TCCC11004 in detergent formulations

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    An extracellular alkaline protease producing strain was isolated from alkaline soil and identified as Bacillus alcalophilus TCCC11004 on the basis of 16S rDNA gene sequencing and biochemical properties. The most appropriate medium for the protease production was composed of (g/l): maltodextrin 110, yeast extract 17.5, cotton seed meal 29.3, K2HPO4 18, trisodium citrate 3.3 and CaCl2 2.6. The alkaline protease TC4 was purified from the culture supernatant by ammonium sulfate precipitation, Sephadex G-75 gel filtration and SP-Sepharose HP ion exchange chromatography, with a 6.8 fold increase in specific activity and 15.2% recovery. The molecular weight was estimated to be 26 kDa on SDS-PAGE. The protease was highly active from pH 9.0-12.0 with an optimal at pH 11.0. It was active at 30 - 60°C and exhibited maximal activity at 50°C. The thermostability of the protease was increased by the addition of CaCl2. It retained 70 and 81% of its initial activity after heating for 2 h at 50°C, in the absence or presence of 2 mM CaCl2, respectively. The enzyme was inactivated by diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride, suggesting that it is a serine protease. The protease was stable in 0.5% SDS and retained 70.3% of its initial activity after 1 h of incubation. It was active in the presence of 3% Triton X-100 with 100% activity and stable towards oxidizing agent with 69.2% activity in the presence of 1% H2O2. The enzyme showed excellent compatibility with commercial detergents such as TaiZi, BiLang, DiaoPai and TianQing, retaining more than 90% of its initial activity in the tested detergents after 1 h of preincubation at 40°C.Keywords: Serine alkaline protease, Bacillus alcalophilus, stability, detergent compatibility

    A Fuzzy Social Network Analysis Method and a Case Study on Tianya

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    Social networking service (SNS) has become online service platforms that focus on facilitating the building of social networks among people who share interests, activities, backgrounds, or real-life connections and has had a rapid development in China in the past few years. This paper aims to develop a fuzzy social network service analysis method, which combines graph theory with related fuzzy approach, to analyze the social network structural features and the distribution characteristics of interpersonal nodes in SNS community. A case study on a very famous Chinese tourism BBS-Tianya-is conducted to illustrate and validate the proposed approach. The research findings are as follows: (1) The attraction degrees of various areas in the forum are significantly different; (2) interpersonal nodes in the forum are concentrated relatively; (3) the fuzzy out-degrees and the fuzzy in-degrees of interpersonal nodes in the forum conflict each other; and (4) the distribution of interpersonal nodes is influenced by geographical relations. These findings can directly support social network service management and particularly tourism online service developments. © Springer-Verlag Berlin Heidelberg 2014

    Chemical Composition, Fiber Morphology, and Pulping of P. Bolleana Lauche

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    The chemical composition and fiber morphology of the P. bolleana Lauche was assessed for its suitability for pulping and papermaking. The P. bolleana Lauche used in this study contained a low amount of lignin, but higher quantities of cellulose and hemicelluloses. It was found that morphological indices of P. bolleana Lauche were adequate for pulping and papermaking. The pulping of this wood was carried out using conventional kraft and soda pulping process under varying conditions. The results indicated that at higher sulfidity (24%-32%) with lower EA (14-16%), higher yields, and viscosity of pulping were obtained with an acceptable kappa number. Kraft pulp of P. bolleana Lauche obtained at given conditions (EA 14-16%; sulfidity 24-32%) provided paper sheets with greater tensile strength, burst index and tear index, at the same beating degree

    Fatigue Crack Initiation and Propagation in Butt Joint Welds of an Ultrahigh-Strength Steel Formulas proposed for predicting fatigue crack intitation and propagation agree well with experimental data

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    ABSTRACT. In this paper, the fatigue crack initiation (FCI) from notches and fatigue crack propagation (FCP) in different zones of welds in butt joints of 30CrMnSiNi2A steel were investigated. General formulas for the FCI life and the FCP rate of the welds are examined, and an approach to predicting the FCI life is offered. Our research indicates that the postweld isothermal quenching treatment improves both the microstructure and fatigue resistance of the welds. Little difference is found in the FCI resistance of the base metal, weld metal and weld interface, although the microstructural effect on the FCP rate is observed. In the near-threshold region, the FCP rates of the weld interface are higher than those of the base metal but lower than those of the weld metal. The discontinuities on the notch surface have a detrimental influence on the FCI resistance of the welds investigated. The results further indicate that, in order to predict the fatigue life of the welded structures accurately, the test results of FCI life and FCP rate should be properly selected according to the FCI location and FCP path in the structures

    Orientation relationships between TiB (B27), B2, and Ti₃Al phases

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    Tellurium quantum dots: Preparation and optical properties

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    Herein, we report an effective and simple method for producing Tellurium Quantum dots (TeQDs), zero-dimensional nanomaterials with great prospects for biomedical applications. Their preparation is based on the ultrasonic exfoliation of Te powder dispersed in 1-methyl-2-pyrrolidone. Sonication causes the van der Waals forces between the structural hexagons of Te to break so that the relatively coarse powder breaks down into nanoscale particles. The TeQDs have an average size of about 4 nm. UV-Vis absorption spectra of the TeQDs showed an absorption peak at 288 nm. Photoluminescence excitation (PLE) and photoluminescence (PL) are used to study the optical properties of TeQDs. Both the PLE and PL peaks revealed a linear relationship against the emission and excitation energies, respectively. TeQDs have important potential applications in biological imaging and catalysis as well as optoelectronics

    Fundamental performance similarities between individual pitch control strategies for wind turbines.

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    The use of blade individual pitch control (IPC) offers a means of reducing the harmful turbine structural loads that arise from the uneven and unsteady forcing from the oncoming wind. In recent years two different and competing IPC techniques have emerged that are characterised by the specific loads that they are primarily designed to attenuate. In the first instance, methodologies such as single-blade control and Clarke Transform-based control have been developed to reduce the unsteady loads on the rotating blades, whilst tilt-yaw control and its many variants instead target load reductions in the non rotating turbine structures, such as the tower and main bearing. Given the seeming disparities between these controllers, the aim of this paper is to show the fundamental performance similarities that exist between them and hence unify research in this area. Specifically, we show that single-blade controllers are equivalent to a particular class of tilt-yaw controller, which itself is equivalent to Clarke~Transform-based control. This means that three architecturally dissimilar IPC controllers exist that yield exactly the same performance in terms of load reductions on fixed and rotating turbine structures. We further demonstrate this outcome by presenting results obtained from high-fidelity closed-loop turbine simulations

    Assessing record linkage between health care and Vital Statistics databases using deterministic methods

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    BACKGROUND: We assessed the linkage and correct linkage rate using deterministic record linkage among three commonly used Canadian databases, namely, the population registry, hospital discharge data and Vital Statistics registry. METHODS: Three combinations of four personal identifiers (surname, first name, sex and date of birth) were used to determine the optimal combination. The correct linkage rate was assessed using a unique personal health number available in all three databases. RESULTS: Among the three combinations, the combination of surname, sex, and date of birth had the highest linkage rate of 88.0% and 93.1%, and the second highest correct linkage rate of 96.9% and 98.9% between the population registry and Vital Statistics registry, and between the hospital discharge data and Vital Statistics registry in 2001, respectively. Adding the first name to the combination of the three identifiers above increased correct linkage by less than 1%, but at the cost of lowering the linkage rate almost by 10%. CONCLUSION: Our findings suggest that the combination of surname, sex and date of birth appears to be optimal using deterministic linkage. The linkage and correct linkage rates appear to vary by age and the type of database, but not by sex
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