The relationship between environmental management systems and organizational innovations

This study provides empirical evidence of the nature of the relationship between environmental management systems and organizational innovations. Using a sample of Spanish manufacturing firms, the study reports on the implementation of the International Organization for Standardization (ISO) 14000 environmental quality standards and the relationship of such implementation with organizational innovations in the firm. The study presents several implications of interest for practitioners, academics, and policy makers. © 2012 Wiley Periodicals, Inc.     

Stigma and barriers to care in soldiers postcombat.

The present study examined the effects of leadership and unit cohesion on mental health stigma and perceived barriers to care. A sample of 680 soldiers from combat support units were surveyed 3 months after their return from combat operations in Iraq. The survey included scales on psychological symptoms and perceptions of leader behaviors and unit cohesion, as well as items assessing stigma and barriers to care. The sample was used to test the independent and interactive effects of leadership and unit cohesion on soldiers’ perceptions of stigma and barriers to care. Analyses yielded significant interaction effects between leadership and cohesion in predicting stigma and barriers to care, while controlling for the effects of mental health symptoms. Soldiers who rated their leaders more highly and who reported higher unit cohesion also reported lower scores on both stigma and perceived barriers to care. Thus, positive leadership and unit cohesion can reduce perceptions of stigma and barriers to care, even after accounting for the relationship between mental health symptoms and these outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional stabilization of cellulase by covalent modification with chitosan

Chitosan was linked to cellulase (EC 3.2.1.4) from Trichoderma viride by covalent conjugation to periodate‐activated carbohydrate moieties of the enzyme. The modified enzyme contained about 1.5 mol of polymer per mol of protein. The specific activity of the conjugate prepared was 39.8% of the native cellulase. The optimum pH and temperature for cellulase remained unaltered after modification. The thermostability was increased by 8.9 °C for the cellulase–chitosan complex. Thermal inactivation at different temperatures ranging from 65 °C to 80 °C was markedly increased for the polymer‐modified enzyme. The stability within the pH range 1.0–3.2 was also improved for the modified enzyme. © 2001 Society of Chemical Industry     

Effect of flow field design on performances of high temperature PEM fuel cells: Experimental analysis

Among all types of fuel cells, attention is being drawn lately on high temperature Polybenzimidazole (PBI) PEM because their operative temperature range (120-180 °C) increases the tolerance to carbon monoxide. This feature allows working with low quality hydrogen produced by hydrocarbon reformation. Most of the literature on PBI PEM deals with membrane and MEA related issues, however, cell efficiency and specially, commercial feasibility are conditioned by other fuel cell components as bipolar plates. In the present study the focus is on the effect of the flow field geometry of high temperature PBI PEM composite bipolar plates on the overall performance of the cell. For this purpose, three different channel geometries are studied: two serpentine flow fields and parallel channels flow field. Results show that serpentine geometry yields higher performance though it introduces higher pressure drop along the cell as well.     

Application of linear-extended neutron diffusion equation in a semi-infinite homogeneous medium

The linear-extended neutron diffusion equation (LENDE) is the volume-averaged neutron diffusion equation (VANDE) which includes two correction terms: the first correction is related with the absorption process of the neutron and the second is a contribution to the neutron diffusion, both parameters are related to neutron effects on the interface of a heterogeneous configuration. In this work an analysis of a plane source in a semi-infinite homogeneous medium was considered to study the effects of the correction terms and the results obtained with the linear-extended neutron diffusion equation were compared against a semi-analytical benchmark for the same case. The comparison of the results demonstrate the excellent approach between the linear-extended diffusion theory and the selected benchmark, which means that the correction terms of the VANDE are physically acceptable.     

A new approach to spatial compression of stereoscopic videos

This paper presents a new spatial compression method specifically designed for stereo videos. Different form current compressors, which simply apply known 2D compression techniques, the method proposed here was developed taking into account specificities of the components of the spatial compression process which may impact the correct depth visualization, named Chrominance Subsampling, Discrete WaveletTransform (DWT) and Quantization. Each component was evaluated analyzing where datalosses occur and proposing ways to provide a good balance between compression ratio and image quality, minimizing losses in depth perception. The evaluations were made using standard objective (PSNR) and subjective (DSCQS) metrics, applied to an anaglyphic stereoscopic video base. The results showedour method is competitive regarding compression rate and providessuperior image quality.     

Monte Carlo Simulation of Massive Absorbers for Cryogenic Calorimeters

There is a growing interest in cryogenic calorimeters with macroscopic absorbers for applications such as dark matter direct detection and rare event search experiments. The physics of energy transport in calorimeters with absorber masses exceeding several grams is made complex by the anisotropic nature of the absorber crystals as well as the changing mean free paths as phonons decay to progressively lower energies. We present a Monte Carlo model capable of simulating anisotropic phonon transport in cryogenic crystals. We have initiated the validation process and discuss the level of agreement between our simulation and experimental results reported in the literature, focusing on heat pulse propagation in germanium. The simulation framework is implemented using Geant4, a toolkit originally developed for high-energy physics Monte Carlo simulations. Geant4 has also been used for nuclear and accelerator physics, and applications in medical and space sciences. We believe that our current work may open up new avenues for applications in material science and condensed matter physics.     

Pharmacokinetics of progesterone in lactating dairy cows: Gaining some insights into the metabolism from kinetic modeling

Progesterone pharmacokinetics were analyzed for plasma hormone concentrations ranging from linear to saturated metabolism in lactating Holstein cows with differing daily milk yields. The adequacy of 2-coupled first-order (bi-exponential equation), hyperbolic (Michaelis-Menten equation), and sigmoidal (Hill equation) kinetic models to describe the experimental progesterone pharmacokinetic profiles was examined on a statistical basis. After nonlinear regression and statistical analysis of the data-fitting capability, a simple one-compartment model based on Hill equation proved to be most adequate. This model indicates an enzyme-catalyzed metabolism of progesterone involving cooperative substrate-binding sites, resulting from allosteric effects that yield a sigmoidal saturation rate curve. Kinetic parameters were estimated for 2 groups of lactating Holstein cows with different daily milk yields. We found, for the first time, a remarkable quantitative agreement of the Hill coefficient value with that reported in pharmacokinetic studies involving cytochrome P450, family 3, subfamily A (CYP3A)-mediated reactions in other mammals, humans included. It seems that positive cooperativity makes enzymes much more sensitive to plasma progesterone concentration, and their activities can undergo significant changes in a narrow range of concentration as characteristic of sigmoidal behavior. Therefore, the values of classical pharmacokinetic parameters, such as the elimination constant, half-life, and clearance rate, were found to be highly dependent on the plasma progesterone concentration.     

A pseudo-transient heat transfer simulation of a continuous casting process,employing the element-free Galerkin method

The present work has been conducted in order to develop a novel solution for the heat transfer problem during the continuous casting of steel billets and blooms, by using the element-free Galerkin method under a pseudo-transient moving cross-section slice approach. The transport laws, non-linear aspects and boundary conditions of the initial value problem have been specified. A detailed explanation concerning the characteristics inherent to the application of the element-free Galerkin method to this problem has also been provided. The feasibility and suitability of this novel approach has been verified by comparison with the numerical techniques proposed and the results reported by other researchers as well as an analytical solution of a simple 1-D alloy solidification problem. The results have revealed that this technique could be used successfully in the pseudo transient moving cross-section solution of the heat transfer problem involved in the continuous casting of blooms and square billets.