物理学中的自然单位方法

分析了物理学中自然单位的特点,用自然单位方法给出了原子物理学中玻尔理论的全部结果．     

Combined aerobic heterotrophic oxidation, nitrification and denitrification in a permeable-support biofilm

A biofilm reactor, termed the permeable-support biofilm (PSB), was developed in which oxygen was supplied to the interior of the biofilm through a permeable membrane. The reactor was tested on filtered sewage supplemented with nutrient broth; the bulk solution was anoxic and the interior of the biofilm was supplied with pure oxygen. All tests were performed on a non-steady state biofilm with a depth of 1 mm. Mass balances on total organic carbon, ammonia, organic nitrogen and nitrate showed that combined heterotrophic oxidation of organics, denitrification and nitrification occurred simultaneously within the biofilm. The advantages of such a reactor are discussed.     

Applications of freeze-fracture replication to problems in materials and colloid science

Understanding the relationship between the molecular structure and the macroscopic properties of polymer solutions and gels, oil-water-surfactant emulsions, lyotropic and thermotropic liquid crystals, colloidal dispersions, detergents, and other such “microstructured fluids” is essential to the optimal use of these commercially important materials. Modern rapid-freezing methods followed by freeze-fracture replication techniques are ideally suited to allow the direct visualization of the three-dimensional structure of the particles or units that make up the dispersion, while simultaneously revealing their orientation and distribution with molecular resolution. This paper reviews the necessary experimental conditions required to successfully exploit the freeze-fracture technique as it applies to microstructured fluid systems. The benefits and limitations of structural studies by freeze-fracture techniques as opposed to the more commonly used light, X-ray, and neutron-scattering methods are discussed. Freeze-fracture replicas can also be imaged by scanning tunneling microscopy to reveal directly three-dimensional fracture contours with improved resolution.     

一个用于取得符号IEC 61508组织性功能安全认证的方法论第一部分:制定策略和确定实施范围

IEC 61508和IEC 61511为那些涉及在危险的与安全相关的环境下运营,同时想证明自身在功能安全管理方面有合规能力和资质的企业设立了一个全球通用的标准.为证明对这些标准的遵循,许多企业都选择通过制定一个战略目标来获得一个第三方权威机构的认证.做到这一点对企业来说是一项重要的成就,它除了要求一个全面完善的工作程序和出色的技术资源,还要求对标准有全面深入的理解、取得最高管理层的支持、需要对安全生命周期与该机构相关的各个阶段有清晰的认识.本文简要介绍了某国际级的安全系统集成商在获取符合IEC 61508标准的第三方功能安全认证的道路上所采用的战略.     

Remote sensing of phytoplankton functional types

The principal goal in early missions of satellite-borne visible spectral radiometry (ocean colour) was to create synoptic fields of phytoplankton biomass indexed as concentration of chlorophyll-a. In the context of climate change, a major application of the results has been in the modelling of primary production and the ocean carbon cycle. It is now recognised that a partition of the marine autotrophic pool into a suite of phytoplankton functional types, each type having a characteristic role in the biogeochemical cycle of the ocean, would increase our understanding of the role of phytoplankton in the global carbon cycle. At the same time, new methods have been emerging that use visible spectral radiometry to map some of the phytoplankton functional types. Here, we assess the state of the art, and suggest paths for future work.     

Using full matching to estimate causal effects in nonexperimental studies: Examining the relationship between adolescent marijuana use and adult outcomes.

Matching methods such as nearest neighbor propensity score matching are increasingly popular techniques for controlling confounding in nonexperimental studies. However, simple k:1 matching methods, which select k well-matched comparison individuals for each treated individual, are sometimes criticized for being overly restrictive and discarding data (the unmatched comparison individuals). The authors illustrate the use of a more flexible method called full matching. Full matching makes use of all individuals in the data by forming a series of matched sets in which each set has either 1 treated individual and multiple comparison individuals or 1 comparison individual and multiple treated individuals. Full matching has been shown to be particularly effective at reducing bias due to observed confounding variables. The authors illustrate this approach using data from the Woodlawn Study, examining the relationship between adolescent marijuana use and adult outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Kanayama et al. (2007).

Reports an error in Testosterone supplementation for depressed men: Current research and suggested treatment guidelines by Gen Kanayama, Revital Amiaz, Stuart Seidman and Harrison G. Pope Jr. (Experimental and Clinical Psychopharmacology, 2007[Dec], Vol 15[6], 529-538). In the Recent Studies section (pp. 531-532), citations to Pope and Katz (2003) should have been to Pope, Kanayama, Cohane, Siegel, and Hudson (2003) to reflect the following source, which was omitted from the reference list: Pope, H. G., Jr., Kanayama, G., Cohane, G., Siegel, A., & Hudson, J. I. (2003). Testosterone gel supplementation for men with refractory depression: A randomized placebo-controlled trial. American Journal of Psychiatry, 160, 105-111. (The following abstract of the original article appeared in record 2007-18976-003.) Several lines of accumulating evidence suggest that testosterone might be effective for the treatment of depression, especially in older men who exhibit low testosterone levels. However, despite the potential promise of this approach, the available literature of controlled studies of testosterone in depression remains extremely limited. Therefore, testosterone treatment of depression must still be considered an experimental procedure. At the present state of research, it appears that testosterone might most likely show benefit as an augmentation strategy in men who exhibit low or borderline testosterone levels and who show only a partial response to conventional antidepressants. In this article, we provide some suggested practical guidelines for the treatment of such individuals. However, it should be recognized that these suggestions are tentative and will likely require revision as additional data become available. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geometric control and tuneable pore size distribution of buckypaper and buckydiscs

The fabrication of buckypaper from unfunctionalised multi-walled carbon nanotubes (MWCNTs) without the aid of surfactants or surface modification techniques is accomplished through a novel and quick frit compression method. The dimensions can be controlled through the size of the syringe housing and the through the mass of carbon nanotubes added. Their thicknesses are typically much larger than surfactant-cast buckypaper and range from 120 μm up to 650 μm; buckypaper with thicknesses larger than 500 μm we call buckydiscs. Buckypaper and buckydiscs are mechanically robust to handle, flexible, stable in solvents and possess larger porosities than Triton-X100 cast buckypaper. They also exhibit a memory effect when bending wetted samples, returning to their former geometry on drying. Buckypaper and buckydiscs were studied by mercury intrusion porosimetry to reveal a defined distribution of mesopores and small macropores that is, along with their density and apparent free volume, dependant on the casting solvent and therefore tuneable. Moreover, the frit compression system also allows control over the 3-dimensional geometry of the buckydiscs during the casting process.