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Smaller Fraction (smaller + fraction)
Selected AbstractsAltered volume and hemispheric asymmetry of the superficial cortical layers in the schizophrenia planum temporaleEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2009John F. Smiley Abstract In vivo structural MRI studies in schizophrenia auditory cerebral cortex have reported smaller volumes and, less consistently, have reported altered hemispheric asymmetry of volumes. We used autopsy brains from 19 schizophrenia and 18 nonpsychiatric male subjects to measure the volume asymmetry of the planum temporal (PT). We then used the most recently autopsied 11 schizophrenia and 10 nonpsychiatric brains to measure the widths and fractional volumes of the upper (I,III) and lower (IV,VI) layers. Measurements of whole PT gray matter volumes did not show significant changes in schizophrenia. Nevertheless, laminar volume measurements revealed that the upper layers of the PT comprise a smaller fraction of the total cortex in schizophrenia than in nonpsychiatric brains. Subdivision of the PT showed that this change was especially prominent caudally, beyond Heschl's gyrus, whereas similar but less pronounced changes were found in the rostral PT and Heschl's gyrus. Complementary measures of laminar widths showed that the altered fractional volume in the caudal left PT was due mainly to ,8% thinner upper layers. However, the caudal right PT had a different profile, with thicker lower layers and comparatively unchanged upper layers. Thus, in the present study, laminar measurements provided a more sensitive method for detecting changes than measurement of whole PT volumes. Besides findings in schizophrenia, our cortical width measurements revealed normal hemispheric asymmetries consistent with previous reports. In schizophrenia, the thinner upper layers of the caudal PT suggest disrupted corticocortical processing, possibly affecting the multisensory integration and phonetic processing of this region. [source] External labor market strategy and career success: CEO careers in Europe and the United StatesHUMAN RESOURCE MANAGEMENT, Issue 3 2009Monika Hamori Abstract In this paper, we examine the career histories of the chief executive officers (CEOs) affiliated with the 500 largest organizations in Europe and the 500 largest in the United States. Our purpose is to determine whether frequent career moves across employers, a phenomenon we label an "external labor market strategy," brings greater career rewards than moves inside the same organization. The results reveal that an external labor market strategy is negatively related to career success. On both continents, CEOs who have spent a smaller fraction of their career in their current organization or have changed employers more often have taken a longer time from the start of their career to be promoted to the most influential corporate positions. The labor market institutions in the 22 countries sampled do not influence the relationship between an external labor market strategy and career success, while the specific geographic region in which the employers are located has a limited impact on this relationship. © 2009 Wiley Periodicals, Inc. [source] Global warming, Bergmann's rule and body mass , are they related?JOURNAL OF ZOOLOGY, Issue 4 2002The chukar partridge (Alectoris chukar) case Abstract Using museum specimens collected in Israel during the second half of the 20th century, no support was found for the hypothesis that body mass and tarsus length of chukar partridges Alectoris chukar has changed as a result of global warming. Body mass showed fluctuations during the year, reaching a maximum in late winter and spring and a minimum in summer. Bergmann's rule predicts that in warm-blooded animals, races from warm regions will be smaller than races from colder regions, and a wider explanation states that body size is positively related to latitude. Because of its topography and varied climate, Israel provides a unique opportunity to separate partly the effect of latitude from that of ambient temperature, thus testing if Bergmann's rule is related to latitude or to climatic variables. We found that body mass (and marginally also tarsus length) declined significantly with decreasing latitude in accordance with the wider explanation of Bergmann's rule, but ambient temperature explained a much smaller fraction of the variation in body mass than latitude. These results weaken the traditional explanation to Bergmann's rule that a heat conservation mechanism causes the latitudinal size variation. [source] Effects of common carp Cyprinus carpio (L.) and feed addition in rohu Labeo rohita (Hamilton) ponds on nutrient partitioning among fish, plankton and benthosAQUACULTURE RESEARCH, Issue 1 2008Mohammad Mustafizur Rahman Abstract The effects of introducing common carp (CC) and of adding artificial feed to fertilized rohu ponds on water quality and nutrient accumulation efficiency were studied. All ponds were stocked with 15 000 rohu ha,1. Treatments included ponds with rohu alone, rohu plus 5000 common carp ha,1 and rohu plus 10 000 CC ha,1. A comparison was also made between supplementally fed and non-fed ponds. The overall highest nitrogen (N) and phosphorus (P) concentrations were observed in ponds with 5000 CC ha,1, followed by ponds with 10 000 and 0 CC ha,1. The largest fractions of N and P inputs accumulating in fish, phytoplankton and zooplankton were observed in ponds with 5000 CC ha,1, followed by ponds with 10 000 CC ha,1 and subsequently ponds without CC. Relatively more nutrients accumulated in benthic organisms in ponds without than in ponds with CC. A smaller fraction of the nutrient input was retained in fish, plankton and benthic organisms in ponds without CC compared with ponds with CC. Compared with 5000 CC ha,1, stocking 10 000 CC ha,1 can be considered as overstocking, because this leads to lower fish production and relatively less nutrients retained in plankton and benthic organisms. [source] Dermally adhered soil: 2.INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2006Reconstruction of dry-sieve particle-size distributions from wet-sieve data Abstract In the evaluation of soil particle-size effects on environmental processes, particle-size distributions are measured by either wet or dry sieving. Commonly, size distributions determined by wet and dry sieving differ because some particles disaggregate in water. Whereas the dry-sieve distributions are most relevant to the study of soil adherence to skin, soil can be recovered from skin only by washing with the potential for disaggregation whether or not it is subsequently wet or dry sieved. Thus, the possibility exists that wet-sieving measurements of the particle sizes that adhered to the skin could be skewed toward the smaller fractions. This paper provides a method by which dry-sieve particle-size distributions can be reconstructed from wet-sieve particle-size distributions for the same soil. The approach combines mass balances with a series of experiments in which wet sieving was applied to dry-sieve fractions from the original soil. Unless the soil moisture content is high (i.e., greater than or equal to the water content after equilibration with water-saturated air), only the soil particles of diameters less than about 63 ,m adhere to the skin. Because of this, the adhering particle-size distribution calculated using the reconstruction method was not significantly different from the wet-sieving determinations. [source] | ||||||||||