Autolytic degradation and microbiological activity in farmed Coho salmon (Oncorhynchus kisutch) during chilled storage

Two deteriorative pathways (autolysis and microbiological activity) were studied in farmed Coho salmon (Oncorhynchus kisutch) for 24 days during chilled storage. These changes were assessed by nucleotide degradation (determination of adenosine 5′-triphosphate and its degradation compounds) and biochemical (pH; content of total volatile base-nitrogen; trimethylamine-nitrogen, TMA-N; histamine) and microbial (total aerobe mesophiles, TAM; coliforms) indices related to bacterial activity. An important nucleotide degradation could be assessed according to the fast inosine 5′-monophosphate formation, followed by degradation into inosine and hypoxanthine; the K value was found to be an accurate tool for the measurement of quality loss throughout the whole experiment. Regarding bacterial activity, contents of TMA-N and histamine and TAM counts assessment showed sharp increases after the end of the microbial lag phase (12–17 days); however, values obtained for histamine content and TAM growth remained below acceptable security limits throughout the whole experiment.     

Catalytic Activity of ZSM-11 Zeolites Modified with Metal Cations for the Ethane Conversion

ZSM-11 zeolite samples differing by their active sites (H⁺ and different metal cations) have been studied in the transformation of ethane into aromatic hydrocarbons. A relationship between Lewis sites increasing–aromatization capacity and possible reaction steps have been suggested.     

What every psychologist should know about the Food and Drug Administration’s black box warning label for antidepressants.

In 2004, the Food and Drug Administration released a black box warning label for all antidepressants, indicating an increased risk for suicidality in children and adolescents. The label was subsequently updated in 2007 to include those up to 24 years of age. Data have since emerged to indicate changes in clinical practice patterns of nonspecialists (i.e., nonpsychiatrists) prescribing medications. Among the changes reported in practice patterns are an increased likelihood of referral and a decreased willingness to prescribe antidepressants. Findings also indicate marked reductions in ambulatory visits for depression among children and adolescents, lower rates of diagnosis of depression in this age group, a spillover effect to adults, inaccurate understanding of the actual risk communicated on the warning label (on the part of primary care practitioners), and increased suicide rates among children and adolescents. Recent findings have important implications for practicing psychologists, and specific recommendations are offered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An experimental evaluation of theory-based mother and mother–child programs for children of divorce.

This study evaluated the efficacy of 2 theory-based preventive interventions for divorced families: a program for mothers and a dual component mother–child program. The mother program targeted mother–child relationship quality, discipline, interparental conflict, and the father–child relationship. The child program targeted active coping, avoidant coping, appraisals of divorce stressors, and mother–child relationship quality. Families with a 9- to 12-year-old child (N ?=?240) were randomly assigned to the mother, dual-component, or self-study program. Postintervention comparisons showed significant positive program effects of the mother program versus self-study condition on relationship quality, discipline, attitude toward father–child contact, and adjustment problems. For several outcomes, more positive effects occurred in families with poorer initial functioning. Program effects on externalizing problems were maintained at 6-month follow-up. A few additive effects of the dual-component program occurred for the putative mediators; none occurred for adjustment problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermodynamic evaluation of hydrogen production for fuel cells by using bio-ethanol steam reforming: Effect of carrier gas addition

Omitting the influence of the addition of carrier gas to the reaction system for hydrogen production by bio-ethanol steam reforming can lead to wrong conclusions, especially when it is going to be made to scale. The effect of carrier gas addition to produce hydrogen using bio-ethanol steam reforming to feed fuel cells was evaluated. Thermodynamic calculations in equilibrium conditions were made, however the analysis derived from them can also be applied to kinetic conditions. These calculations were made by using the Aspen-HYSYS software at atmospheric pressure and different values of temperature, water/ethanol molar ratios, and inert (argon)/(water/ethanol) molar ratios. The addition of inert carrier gas modifies the concentrations of the reaction products in comparison to those obtained without its presence. This behavior occurs because most of the reactions which take place in bio-ethanol steam reforming have a positive difference of moles. This fact enhances the system sensitivity to inert concentration at low and moderated temperatures (<700 °C). At high values of temperature, the inert addition does not influence the composition of the reaction products because of the predominant effect of inverse WGS reaction.     

Determination of cadmium at ultra-trace levels by CPE–molecular fluorescence combined methodology

A highly sensitive micelle-mediated extraction methodology for the preconcentration and determination of trace levels of cadmium by molecular fluorescence has been developed. Metal was complexed with o-phenanthroline (o-phen) and eosin (eo) at pH 7.6 in buffer Tris medium and quantitatively extracted into a small volume of surfactant-rich phase of PONPE 7.5 after centrifugating. The chemical variables affecting cloud point extraction (CPE) were evaluated and optimized. The RSD for six replicates of cadmium determinations at 0.84 μg L⁻¹ level was 1.17%. The linearity range using the preconcentration system was between 2.79 × 10⁻³ μg L⁻¹ and 2.81 μg L⁻¹ with a correlation coefficient of 0.99. Under the optimal conditions, it obtained a LOD of 8.38 × 10⁻⁴ μg L⁻¹ and LOQ of 2.79 × 10⁻³ μg L⁻¹. The method presented good sensitivity and selectivity and was applied to the determination of trace amounts of cadmium in commercially bottled mineral water, tap water and water well samples with satisfactory results. The proposed method is an innovative application of CPE-luminescence to metal analysis comparable in sensitivity and accuracy with atomic spectroscopies.     

Gas holdup and mass transfer in solid suspended bubble columns in presence of structured packings

Electrochemical gas absorption or biotechnical purification processes using structured packing as electrode or as biological support, respectively, may operate in bubble columns in presence of suspended solids. In both systems the knowledge of mass transfer rates from the liquid to the packing is important for the design of equipment. In the present investigation, the fluid dynamic behavior of a simple bubble column and a bubble column containing small size particles, both in presence of structured packing, was studied. Furthermore, mass transfer coefficients between the liquid and the structured packing were obtained by the electrochemical method. The influence of physical properties of the liquid phase, gas flow rate, kind and concentration of the suspended particles on both gas holdup and mass transfer was investigated. Correlations of the experimental data of mass transfer using dimensionless groups were derived and compared to previous correlations. Similarity with a heat transfer expression already used in two-phase systems was found.     

Modified sum-product algorithms for decoding low-density parity-check codes

The authors deal with the sum-product algorithm (SPA) based on the hyperbolic tangent (tanh) rule when it is applied for decoding low-density parity-check (LDPC) codes. Motivated by the finding that, because of the large number of multiplications required by the algorithm, an overflow in the decoder may occur, two novel modifications of the tanh function (and its inverse) are proposed. By means of computer simulations, both methods are evaluated using random-based LDPC codes with binary phase shift keying (BPSK) signals transmitted over the additive white Gaussian noise (AWGN) channel. It is shown that the proposed modifications improve the bit error rate (BER) performance up to 1 dB with respect to the conventional SPA. These results have also shown that the error floor is removed at BER lower than 10^-6. Furthermore, two novel approximations are presented to reduce the computational complexity of the tanh function (and its inverse), based on either a piecewise linear function or a quantisation table. It is shown that the proposed approximations can slightly improve the BER performance (up to 0.13 dB) in the former case, whereas small BER performance degradation is observed (<0.25 dB) in the latter case. In both cases, however, the decoding complexity is reduced significantly     

Channeling characterization of defects in silicon: an atomistic approach

We review here the possibilities opened by a recent development of the Monte Carlo binary collision approximation (MC-BCA) simulation of Rutherford backscattering spectrometry-channeling (RBS-C) spectra for the study of radiation damage in monocrystalline materials. The ion implantation of silicon has been chosen as a case study. Atomic-scale modeling of defect structures was used to determine the location of interstitial atoms in the host lattice. Among possible candidate defects, we have considered the elementary hexagonal, tetrahedral, 1 1 0-split interstitials, the Bond-defect and one type of tetra-interstitial cluster. For each defect model a large Si supercell was populated with a proper defect depth distribution and then it was structurally relaxed by the application of the classical EDIP potential. This model system was then given as an input to the MC-BCA simulation code and the spectra corresponding to nine different axial and planar alignments were calculated. For low defect concentration (a few atomic percent), the scattering yields are strongly dependent on the orientation and a distinct signature characteristic of the limited number of allowed interstitial positions in Si could be found. The comparison of simulations and experiments in the case of 180 keV self ion implantation allowed the identification of the dominant interstitial defect whose structural properties are represented by the split-1 1 0 interstitial. By increasing the concentration of defects (and their mutual interaction) the technique looses sensitivity and, at the same time, the contribution of lattice relaxation becomes important. Under these conditions, although the RBS-C response becomes similar to the one obtained from a random distribution of displaced atoms, the major structural features of a heavily damaged sample could be still observed.