Incorporating Both Physical and Kinetic Limitations in Quantifying Dissolved Oxygen Flux to Aquatic Sediments

Traditionally, dissolved oxygen (DO) fluxes have been calculated using the thin-film theory with DO microstructure data in systems characterized by fine sediments and low velocities. However, recent experimental evidence of fluctuating DO concentrations near the sediment-water interface suggests that turbulence and coherent motions control the mass transfer, and the surface renewal theory gives a more mechanistic model for quantifying fluxes. Both models involve quantifying the mass transfer coefficient (k) and the relevant concentration difference (ΔC). This study compared several empirical models for quantifying k based on both thin-film and surface renewal theories, as well as presents a new method for quantifying ΔC (dynamic approach) that is consistent with the observed DO concentration fluctuations near the interface. Data were used from a series of flume experiments that includes both physical and kinetic uptake limitations of the flux. Results indicated that methods for quantifying k and ΔC using the surface renewal theory better estimated the DO flux across a range of fluid-flow conditions.     

Creativity and domain specificity: The effect of task type on multiple indexes of creative problem-solving.

This study addresses the issue of domain specificity within creativity by understanding the characteristics of creative tasks and how participants react to the task. Participants (N = 187) were given 1 of 3 realistic everyday problems to solve. The problems differed in terms of complexity, involvement, and problem-based efficacy. Problem solutions were evaluated on several measures of creativity. Results indicate that creativity was influenced by the type of problem solved and the measure of creativity used to evaluate the solution. Furthermore, these results were obtained after controlling for the effect of ability. Results imply that not all real-world problems are equivalent and that researchers need to investigate how reactions to different problems and the creativity index used may influence conclusions regarding creative problem solving. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of silane functionalization of montmorillonite on epoxy/montmorillonite nanocomposite

Mechanical and dynamic mechanical properties of various montmorillonite (MMT)/epoxy nanocomposites were investigated. 3-aminopropyltriethoxysilane functionalized MMT was compared with commercial pristine MMT and ammonium salt substituted MMT. Qualitative evidence of silane functionalization was confirmed by FT-IR. XRD and TEM were used to characterize the degree of intercalation of MMT in epoxy nanocomposite. Tensile stress and elongation of MMT/epoxy nanocomposite were improved significantly by the silane functionalization of MMT. Dynamic mechanical analysis showed that silane functionalization of MMT resulted in active interactions between MMT and epoxy.     

Jewish quotas in clinical psychology?: The Journal of Clinical Psychology and the scandal of 1945.

In 1945 Frederick Thorne, editor of the Journal of Clinical Psychology, proposed to limit the acceptance of Jewish applicants to clinical psychology graduate schools. A public scandal erupted over this proposed limit, which was modeled on Jewish quotas in medical education. Criticized by the mass media and most psychologists, Thorne’s proposal was repudiated by the Eastern Psychological Association and the Society for the Psychological Study of Social Issues. Using private correspondence, oral histories, and published articles, this mostly forgotten episode in the history of clinical psychology is recreated. It is argued that the 1945 campaign against Jewish quotas prepared activists for the 1950s campaign against racial segregation and the Brown v. Board of Education Supreme Court case. Because the participants in 1945 came from all specialties in psychology, it is suggested that this story is of significance to the field as a whole, rather than just to historians of social issues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

UNSTRUCTURED FINITE-VOLUME METHOD FOR RADIATIVE HEAT TRANSFER IN A COMPLEX TWO-DIMENSIONAL GEOMETRY WITH OBSTACLES

The radiative heat transfer in a complex two-dimensional enclosure with obstacles with participating medium is very important in practical engineering applications. In order to deal with this problem, in this study the finite-volume method (FVM) for radiation has been derived using the unstructured grid system. A general discretization equation was formulated by introducing the directional weight and the step scheme for spatial differencing. For its comparison and validation, two test cases, an equilateral triangular enclosure and a square enclosure with baffle, were chosen. Then, more complex and practical cases, such as a semicircular enclosure with cylinder hole, a square enclosure with finned internal cylinder, and a furnace with embedded cooling pipes, were investigated. All the results obtained by the unstructured FVM agreed very well with the exact solutions as well as the results obtained by the zone method. Furthermore, the wiggling behavior occurring in the blocked-off FVM was not produced by the unstructured FVM. Three types of manipulation of control angle overlap were also examined here. It was found that the solutions depended on the type of manipulation of control angle overlap, especially when the number of control angles was small. Usually, both the pixelation method and exact treatment introduced here yielded better solutions than the bold approximation.     

偷菜现象，竟是必然

2009年，“偷菜”是白领群体中的热门话题，上班时间扫荡他人菜地，午餐时间交流经验已经成了不少人每天的必修课，以至于一些企业不得不“封杀”该类网站。我的一位朋友就是一个狂热的偷菜一族，每天掐着时间将朋友们的菜地洗劫一空。     

Caulerpa lentillifera inhibits protein-tyrosine phosphatase 1B and protects pancreatic beta cell via its insulin mimetic effect

Food Science and Biotechnology - The aim of this study was to determine whether Caulerpa lentillifea extract (CLE) can protect pancreatic beta cells and enhance insulin signaling in adipocytes. We...