Monolithic Friction and Contact Handling for Rigid Bodies and Fluids Using SPH

We propose a novel monolithic pure SPH formulation to simulate fluids strongly coupled with rigid bodies. This includes fluid incompressibility, fluid–rigid interface handling and rigid–rigid contact handling with a viable implicit particle-based dry friction formulation. The resulting global system is solved using a new accelerated solver implementation that outperforms existing fluid and coupled rigid–fluid simulation approaches. We compare results of our simulation method to analytical solutions, show performance evaluations of our solver and present a variety of new and challenging simulation scenarios.     

Safety and Insecurity: Exploring the Moderating Effect of Organizational Safety Climate.

This research reconciled disparate findings regarding the relationship between job insecurity and safety by examining organizational safety climate as a potential moderator. It was predicted that a strong organizational safety climate would attenuate the negative effects of job insecurity on self-reported safety outcomes such as safety knowledge, safety compliance, accidents, and injuries. Data collected from 136 manufacturing employees were consistent with these predictions. Results are discussed in light of escalating interest in how organizational factors can affect employee safety. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role-Based Access Controls: Status, Dissemination, and Prospects for Generic Security Mechanisms

E-commerce applications have diverse security requirements ranging from business-to-business over business-to-consumer to consumer-to-consumer types of applications. This range of requirements cannot be handled adequately by one single security model although role-based access controls (RBAC) depict a promising fundament for generic high-level security. Furthermore, RBAC is well researched but rather incompletely realized in most of the current backend as well as business layer systems. Security mechanisms have often been added to existing software causing many of the well-known deficiencies found in most software products. However, with the rise of component-based software development security models can also be made available for reuse. Therefore, we present a general-purpose software framework providing security mechanisms such as authentication, access controls, and auditing for Java software development. The framework is called GAMMA (Generic Authorization Mechanisms for Multi-Tier Applications) and offers multiple high-level security models (including the aforementioned RBAC) that may even be used concurrently to cover such diverse security requirements as found within e-commerce environments.     

Heavy metal distribution in some French forest soils: evidence for atmospheric contamination

This study is one of very few dealing with the distribution and the origin of heavy metals in French soils from a priori non-polluted forest areas. The abundance of heavy metals measured in these soils decreases as follows: Cr>Zn>Pb>Ni>Cu>Co>Cd. Total concentrations of Pb, Cr and Ni in some soils exceed the European thresholds for non-polluted soils and even the French association of normalization critical values for sludge spreading. The lowest heavy metal contents are observed in acid soils while the highest concentrations are in the calcaric cambisol and in the mollic andosol, which is rather scarce as compared with the other French forest soils. With the exception of the podzol, Cr and Ni concentrations increase with depth in all soil profiles. The distribution pattern of Co, Cu, Zn depends on the soil characteristics. In some acid soils, however, Cu and Zn decrease with depth. Pb and Cd are accumulated in the upper soil horizons. Heavy metals accumulate in deep soil horizons in relation to important clay content in the dystric planosol and stagnic luvisol. The concentration of each heavy metal is always controlled by different parameters (soil pH, iron and aluminum oxide content, clay content, organic matter and cation exchange capacity), which are heavy metal specific. This study highlights the metal-trapping character of andosol and calcaric soil, the weak heavy metal retention in acid soils, the leaching and trapping character in leached clayed soils, and the migration of heavy metals in the podzol. Pb and Cr concentrations indicate a significant enrichment in surface horizons from various soils in areas which receive significant acid atmospheric pollution. Particularly, the highest Pb content is observed in a soil located in the N-NE part of France. Lead isotope ratios measured in the cambic podzol and the calcaric cambisol, exhibit the importance of the anthropogenic sources and particularly the influence of global atmospheric inputs from leaded gasoline compared to regional and local industrial emissions. The anthropogenic Pb contribution is estimated to 83, 30 and 11%, respectively, for surface, intermediate and deep horizons of the cambic podzol located in the northern part of France, and to 68% in surface horizon of the calcaric cambisol located in the Alps.     

Occurrence and inheritance of linolenic and linoleic acids in soybean seeds

The range of linolenic acid in the oil from 251 field-grown varieties and introductions of soybeans was 4.89 to 9.28% and that of linoleic, 35.8 to 53.4%. Crosses of varieties and introductions “high” and “low” linolenic acid indicated that inheritance of both acids was quantitative rather than qualitative. Transgressive segregation, particularly to low values, was observed occasionally. However 3.35% was the lowest linolenic acid value observed. Environmental effects markedly influenced the quantity of both acids. F₂ plants from one cross (P.I.80476×P.I.85671), grown in the greenhouse, showed a dissimilar type of frequency distribution for the two acids but a significant positive correlation (P<1%) between their percentages. A similar relation was not detected for field-grown plants. Journal paper No. 1593, Purdue University Agricultural Experiment Station. Journal paper No. 346, U.S. Regional Soybean Laboratory. Crops Research Division, Agricultural Research Service, U.S. Department of Agriculture.     

Expression of acetylcholinesterase messenger RNA in human brain: an in situ hybridization study

The distribution of messenger RNA coding for acetylcholinesterase was studied in human post mortem brain and rhesus monkey by in situ hybridization histochemistry and compared to the distribution of acetylcholinesterase activity. Acetylcholinesterase messenger RNA had--similar to acetylcholinesterase enzymatic activity--a widespread distribution in human bain. Acetylcholinesterase messenger RNA positive cells corresponded to perikarya rich in acetylcholinesterase activity in most but not all regions. Examples for mismatches included the inferior olive and human cerebellar cortex. The presence of hybridization signals in cerebral cortex and an enrichment in layer III and V of most isocortical areas confirmed that perikaryal acetylcholinesterase in cerebral cortex is of postsynaptic origin and not derived from cholinergic projections. In striatum the expression of high levels of acetylcholinesterase messenger RNA was restricted to a small population of large striatal neurons. In addition, low levels of expression were found in most medium sized striatal neurons. Cholinergic neurons tended to express high levels of acetylcholinesterase messenger RNA whereas in cholinoceptive neurons the levels were moderate to low. However, some noncholinergic neurons like dopaminergic cells in substantia nigra, noradrenergic cells in locus coeruleus, serotoninergic cells in raphé dorsalis, GABAergic cells in thalamic reticular nucleus, granular cells in cerebellar cortex and pontine relay neurons expressed levels comparable to cholinergic neurons in basal forebrain. It is suggested that neurons expressing high levels of acetylcholinesterase messenger RNA may synthesize acetylcholinesterase for axonal transport whereas neurons with an expression of acetylcholinesterase confined to somatodendritic regions tend to contain lower levels of acetylcholinesterase messenger RNA.     

Antibodies to chlamydia trachomatis in semen and relationship with parameters of male fertility

To screen for infection with Chlamydia trachomatis in semen samples from asymptomatic men in couples consulting for infertility and to determine the relationship of seminal chlamydial antibodies with clinically relevant parameters of male fertility, 197 randomly chosen patients were enrolled in a prospective study. The median duration of infertility was 4 years (range 1-18). Screening for C. trachomatis and chlamydial antibodies of the immunoglobulin (Ig) A and IgG classes were performed in ejaculates and, in parallel, endocervical material from the partners of the patients and serum samples from both partners were evaluated. A comprehensive examination of semen quality included sperm analyses, semen cultures, local antisperm antibody (ASA) testing, the determination of potential infection markers, and sperm-cervical mucus interaction testing in vitro (SCMPT) and in vivo (post-coital testing). Chlamydial IgA antibodies were found in the semen samples of 18.8% (37/197) of the patients, while chlamydial IgG antibodies were found in 8.1% (16/197) of the patients. Screening for C. trachomatis was negative in all semen and cervical specimens. Only 5.5% of men remembered a past genital infection. Chlamydia antibodies (IgA/Ig/G) in semen were significantly correlated with chlamydia IgG antibodies in serum samples (P < 0.001). No marked relationship was found between the presence of seminal chlamydial antibodies and the major parameters of sperm analysis, semen cultures, local ASA and sperm penetration testing as an indicator of functional capacity. Seminal chlamydial antibodies were not significantly associated with potential infection or inflammation markers in aliquots of the same ejaculates. However, a significant relationship of chlamydial antibodies in patients' semen with past genital infections of their female partners was found with clinical relevance for a tubal infertility factor. The results indicate that in asymptomatic patients the presence of chlamydial antibody IgA or IgG in semen is not associated with reduced semen quality, potential seminal infection markers or impaired functional capacity as important determinants of male fertility; however, seminal chlamydial antibodies suggesting a previous sexually transmitted disease are significantly related to a tubal infertility factor of female partners.     

X-ray fluorescence measurements of thin film chalcopyrite solar cells

X-ray fluorescence has turned out to be a very suitable and reliable tool for the characterization of thin film chalcopyrite solar cells. Besides the composition determination in atomic percent the total mass per unit square (mg/cm²) of the analyzed elements and the film thickness can be measured accurately. Furthermore, a real multi-layer analysis allows in addition to determine the CdS, ZnO and Mo thickness simultaneously with the absorber measurement. By the use of etching techniques, information about a vertical composition gradient can also be obtained. This work shows the possibilities and limitations of the X-ray fluorescence technique for the chalcopyrite solar cell characterization and emphasizes the advantages over the widespread electron probe microanalysis.