Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site

Diffuse pollution of surface soil with polycyclic aromatic hydrocarbons (PAHs) is problematic in terms of the large areas and volumes of polluted soil. The levels and effects of diffuse PAH pollution at a motorway site were investigated. Surface soil was sampled with increasing distance from the asphalt pavement and tested for total amounts of PAHs, amounts of bioaccessible PAHs, total bacterial populations, PAH degrader populations, the potential for mineralization of 14C-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled at greater distances (12-24 m) contained only background levels of PAHs. The total bacterial populations (CFU and numbers of 16S rDNA genes) were similar for all soil samples, whereas the microbial degrader populations (culturable PAH degraders and numbers of PAH dioxygenase genes) were most abundant in the most polluted samples close to the pavement. Hydroxypropyl-beta-cyclodextrin extraction of soil PAHs, as a direct estimate of the bioaccessibility, indicated that only 1-5% of the PAHs were accessible to soil bacteria. This low bioaccessibility is suggested to be due to sorption to traffic soot particles. The increased PAH level close to the pavement was reflected in slightly increased mutagenic activity (1 m, 0.32 +/- 0.08 revertants g(-1) soil; background/ 24 m: 0.08 +/- 0.04), determined by the Salmonella/ microsome assay of total extractable PAHs activated by liver enzymes. The potential for lighter molecular weight PAH degradation in combination with low bioaccessibility of heavier PAHs is proposed to lead to a likely increase in concentration of heavier PAHs over time. These residues are, however, likely to be of low biological significance.     

Neuropsychological impairments in schizophrenia: Integration of performance-based and brain imaging findings.

[Correction Notice: An erratum for this article was reported in Vol 134(3) of Psychological Bulletin (see record 2008-04614-006). In the article "Neuropsychological Impairments in Schizophrenia: Integration of Performance-Based and Brain Imaging Findings," by Abraham Reichenberg and Philip D. Harvey (Psychological Bulletin, 2007, Vol. 133, No. 5, pp. 833-858), on page 837, right column, first paragraph; in Table 1 (p. 835); and in Table 2 (p. 843), the word perseverations was misspelled as preservations. In addition, on page 846, left column, third paragraph, the last word in the sentence was incorrect. The correct word should be hyperactivation.] Until recently, the dominant view was that schizophrenia patients have limited, if any, neuropsychological impairments, and those that are observed are only secondary to the florid symptoms of the disorder. This view has dramatically changed. This review integrates recent evidence demonstrating the severity and profile of neuropsychological impairments in schizophrenia. We present quantitative evaluation of the literature demonstrating that the most severe impairments are apparent in episodic memory and executive control processes, evident on a background of a generalized cognitive deficit. The neuropsychological impairments potentially represent genetic liability to the disorder, as similar, yet milder, impairments are evident in schizophrenia patients even before the onset of psychotic symptoms, as well as in the nonpsychotic relatives of schizophrenia patients. Corresponding cognitive neuroimaging literature on executive functions, episodic memory, and working memory in schizophrenia documenting abnormalities in frontal and medial temporal lobes is summarized, and current models integrating neuropsychological and neuroimaging data are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dampening variations in wind power generation—the effect of optimizing geographic location of generating sites

This paper presents a method to dampen the variations in the output of aggregated wind power through geographic allocation of wind power generation sites. The method, which is based on the sequential optimization of site localization, is applied to the Nordic countries and Germany, using meteorologic wind speed data as the input. The results show that the variability in aggregated wind power output mitigates by applying sequential optimization. For the data used in this work, the coefficient of variation (standard deviation/mean) was 0.54 for the optimized aggregation of sites, as compared with 0.91 for the present day installation. An optimal allocation of wind power generation site reduces the need for dispatch and other measures to deal with the intermittent nature of wind power. Copyright © 2013 John Wiley & Sons, Ltd.     

Phototoxicity of pyrene affects benthic algae and bacteria from the Arctic

Phototoxicity of polycyclic aromatic hydrocarbons (PAHs) in the Arctic is important to study since the future PAH load is likely to increase. In combination with the increased UV-light penetration due to ozone layer thinning, phototoxicity may be a potential problem for arctic areas. The aim of this study was to evaluate effects of pyrene and phototoxicity of pyrene on natural algae and bacteria from arctic sediments. Sediments from a shallow-water marine baywere spiked with different pyrene concentrations. Microcosms containing the sediment were incubated under three light regimes, natural sunlight with UV-light, natural sunlight without UV-light, and dark. Significant effects were evident at low pyrene concentrations, particularly in presence of UV-light, indicating phototoxicity. The microalgae were especially sensitive to the phototoxicity of pyrene. Already atthe lowest pyrene concentration (Cfree: 4 nM) algal 14C-incorporation and chlorophyll a content were reduced. The toxic effects of pyrene on the microalgae probably led to the release of organic matter. In agreement with this, bacterial activity increased at high pyrene concentrations indicated by increased oxygen consumption and increased release of inorganic N and P from the sediment. This study indicates that phototoxicity of PAHs may be relevant for sediment communities from shallow marine arctic areas at environmentally relevant pyrene concentrations.     

"Neuropsychological impairments in schizophrenia: Integration of performance-based and brain imaging findings": Correction.

Reports an error in "Neuropsychological impairments in schizophrenia: Integration of performance-based and brain imaging findings" by Abraham Reichenberg and Philip D. Harvey (Psychological Bulletin, 2007[Sep], Vol 133[5], 833-858). In the article, on page 837, right column, first paragraph; in Table 1 (p. 835); and in Table 2 (p. 843), the word perseverations was misspelled as preservations. In addition, on page 846, left column, third paragraph, the last word in the sentence was incorrect. The correct word should be hyperactivation. (The following abstract of the original article appeared in record 2007-12463-006.) Until recently, the dominant view was that schizophrenia patients have limited, if any, neuropsychological impairments, and those that are observed are only secondary to the florid symptoms of the disorder. This view has dramatically changed. This review integrates recent evidence demonstrating the severity and profile of neuropsychological impairments in schizophrenia. We present quantitative evaluation of the literature demonstrating that the most severe impairments are apparent in episodic memory and executive control processes, evident on a background of a generalized cognitive deficit. The neuropsychological impairments potentially represent genetic liability to the disorder, as similar, yet milder, impairments are evident in schizophrenia patients even before the onset of psychotic symptoms, as well as in the nonpsychotic relatives of schizophrenia patients. Corresponding cognitive neuroimaging literature on executive functions, episodic memory, and working memory in schizophrenia documenting abnormalities in frontal and medial temporal lobes is summarized, and current models integrating neuropsychological and neuroimaging data are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sample-tip interaction of piezoresponse force microscopy in ferroelectric nanostructures

We report on qualitative and quantitative implications of the sample-tip interaction in piezoresponse force microscopy. Our finite-element analysis of adsorbate effects, sample heterogeneities, and tip asymmetries is in agreement with experimental observation of ferroelectric nanostructures. Qualitative discrepancies arise from locally asymmetric tip-sample interaction. Any quantitative determination of field-related material parameters as required for the verification of semiempirical models of the ferroelectric limit typically relies on an overestimated field across the sample. Our findings indicate that adsorbates reduce the actual field across the nanograin by roughly one order of magnitude.     

Diffusion of PAH in potato and carrot slices and application for a potato model

A method for quantifying the effect of medium composition on the diffusive mass transfer of hydrophobic organic chemicals through thin layers was applied to plant tissue. The method employs two silicone disks, one serving as source and one as sink for a series of PAHs diffusing through thin layers of water, potato tissue, and carrot tissue. Naphthalene, phenanthrene, anthracene, and fluoranthene served as model substances. Their transfer from source to sink disk was measured by HPLC to determine a velocity rate constant proportional to the diffusive conductivity. The diffusive flux through the plant tissue was modeled using Fick's first law of diffusion. Both the experimental results and the model suggest that mass transfer through plant tissue occurs predominantly through pore water and that, therefore, the mass transfer ratio between plant tissue and water is independent of the hydrophobicity of the chemical. The findings of this study provide a convenient method to estimate the diffusion of nonvolatile organic chemicals through various plant materials. The application to a radial diffusion model suggests that "growth dilution" rendersthe concentration of highly hydrophobic chemicals in potatoes below their equilibrium partitioning level. This is in agreement with field results for the bioconcentration of PAHs in potatoes.     

Dual-task information processing in schizotypal personality disorder: Evidence of impaired processing capacity.

Working memory theories heavily rely on the concept of processing resources and the their efficient deployment. Some recent work with schizophrenia-spectrum patients has suggested that many associated cognitive impairments may be reduced to deficits in working memory, possibly related to reductions in information-processing capacity resources. In this study, 38 patients with schizotypal personality disorder (SPD), 22 patients with other personality disorders, and 14 healthy comparison participants performed a dual-task processing assessment that was designed specifically for use in this type of study. Participants recalled lists of digits at their predetermined maximum digit span and performed box-checking tests, first alone and then in a dual-task format. Instructions included equal prioritization of both tasks. SPD patients had significantly shorter digit spans, and they also showed more deterioration on both tasks. Performance operating characteristics curves indicated that SPD patients' reduced performance was not due to abnormal resource allocation strategies leading to strategic failures. The authors discuss the implications of these processing capacity limitations for understanding both the signature of cognitive impairment within the schizophrenia spectrum and general abnormalities in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geographic aggregation of wind power—an optimization methodology for avoiding low outputs

This work investigates macro‐geographic allocation as a means to improve the performance of aggregated wind power output. The focus is on the spatial smoothing effect so as to avoid periods of low output. The work applies multi‐objective optimization, in which two measures of aggregated wind power output variation are minimized, whereas the average output is maximized. The results show that it is possible to allocate wind power so that the frequency of low outputs is substantially reduced, while maintaining the average output at around 30% of nameplate capacity, as compared with the corresponding output of 20% for the present allocation system. We conclude that in a future, fully electrically integrated Europe, geographic allocation can substantially reduce instances of low aggregate output, while impairing little on capacity factor and at the same time providing reduction in of short‐term jumps in output. Copyright © 2016 John Wiley & Sons, Ltd.     

Stability in schizophrenia symptoms over time: Findings from the Mount Sinai Pilgrim Psychiatric Center Longitudinal Study.

This study examined the stability of symptoms of schizophrenia over time, focusing on the stability of symptom structure. Symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). The sample consisted of 215 chronic patients followed up for as long as 4 years. Exploratory factor analysis identified 6 factors. Several statistical techniques were used to examine the stability of these symptoms, including longitudinal confirmatory factor analysis. Low-to-moderate rank-order stability and high absolute stability of the factors were found, with the structure of the PANSS-assessed symptoms consistent over time. The results demonstrate that despite changes in the severity of symptoms in individual patients with schizophrenia, the factor structure and interrelatedness of symptoms have considerable stability over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)