5,837 research outputs found
The relationship between employee personality traits and preferred leadership style
Purpose. The purpose of this study is to examine how employee personality traits are related to a preferred leadership style and how the differences between preferred and actual leadership style relate to employee perceptions of leader satisfaction and effectiveness. Respondents completed a survey questionnaire that consisted of the commonly used Multi-Factor Leadership Questionnaire Form 5X to assess employee leadership preferences and the NEO-FF1 to identify personality traits. The relationship between employee personality traits and their preferred leadership style is significant to leaders who believe that it is possible to adjust a leadership approach to improve organizational performance; Findings. Agreeableness is positively related and age is negatively related to a transformational leadership preference. The results also indicate a negative relationship between the difference between preferred and actual leadership and ratings of employee satisfaction and ratings of leader effectiveness. Last, employee satisfaction is positively related to ratings of leader effectiveness
Nonproductive Events in Ring-Closing Metathesis Using Ruthenium Catalysts
The relative TONs of productive and nonproductive metathesis reactions of diethyl diallylmalonate are compared for eight different ruthenium-based catalysts. Nonproductive cross metathesis is proposed to involve a chain-carrying ruthenium methylidene. A second more-challenging substrate (dimethyl allylmethylallylmalonate) that forms a trisubstituted olefin product is used to further delineate the effect of catalyst structure on the relative efficiencies of these processes. A steric model is proposed to explain the observed trends
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Data compression for climate data
The different rates of increase for computational power and storage capabilities of supercomputers turn data storage into a technical and economical problem. Because storage capabilities are lagging behind, investments and operational costs for storage systems have increased to keep up with the supercomputers' I/O requirements. One promising approach is to reduce the amount of data that is stored. In this paper, we take a look at the impact of compression on performance and costs of high performance systems. To this end, we analyze the applicability of compression on all layers of the I/O stack, that is, main memory, network and storage. Based on the Mistral system of the German Climate Computing Center (Deutsches Klimarechenzentrum, DKRZ), we illustrate potential performance improvements and cost savings. Making use of compression on a large scale can decrease investments and operational costs by 50% without negatively impacting performance. Additionally, we present ongoing work for supporting enhanced adaptive compression in the parallel distributed file system Lustre and application-specific compression
Oxidative stress stimulates alpha-tocopherol transfer protein in human trophoblast tumor cells BeWo
alpha-Tocopherol transfer protein (alpha-TTP) has been identified as the major intracellular transport protein for the antioxidant vitamin E (alpha-Tocopherol). Expression of alpha-TTP on the reproductive system has been described both in mouse uterus and lately in the human placenta. The aim of this study was to clarify if placental expression of alpha-TTP can be modified by substances causing oxidative reactions. The human choriocarcinoma cell line BeWo was, therefore, treated with two known pro-oxidants. alpha-TTP expression was determined with immunocytochemistry and evaluated by applying a semiquantitative score. The presence of pro-oxidants in BeWo cells induced alpha-TTP expression. We thus hypothesize that stimulation of alpha-TTP expression by oxidative stress, as this was induced by pro-oxidants, could be part of an antioxidant process occurring in the placenta in the aim of enhancing the supply of alpha-Tocopherol. This process could occur both in normal pregnancies, as well as in pregnancy disorders presented with intensified oxidative stress. In that view, this model is proposed for further oxidative stress studies on trophoblast and placenta, on the grounds of clarifying the role of alpha-Tocopherol in pregnancy physiology and pathophysiology
Friction mechanisms Wear mechanisms Abrasive wear Adhesive
Abstract Friction and wear tests were performed with a number of greases based on biogenic esters and thickened with two metal soaps and a highly dispersed silica acid gel. The series of experiments was performed on a Nonotribometer in material combination of sapphire ball on steel disks with a range of normal loads from 1 up to 500 mN. Results directly show influences of the bulk grease components on frictional and wear behavior. Comparison of frictional and wear results makes manifest that, while in most combinations of base oil and thickener, the highest influence is found in the thickening agent, some combinations are mainly influenced by the base oil. All frictional results along with wear widths and depths as well as micrographs of the prevailing wear mechanisms are presented and discussed
Spiral Growth and Step Edge Barriers
The growth of spiral mounds containing a screw dislocation is compared to the
growth of wedding cakes by two-dimensional nucleation. Using phase field
simulations and homoepitaxial growth experiments on the Pt(111) surface we show
that both structures attain the same characteristic large scale shape when a
significant step edge barrier suppresses interlayer transport. The higher
vertical growth rate observed for the spiral mounds on Pt(111) reflects the
different incorporation mechanisms for atoms in the top region and can be
formally represented by an enhanced apparent step edge barrier.Comment: 11 pages, 4 figures, partly in colo
A Nonpolar Blueberry Fraction Blunts NADPH Oxidase Activation in Neuronal Cells Exposed to Tumor Necrosis Factor-α
Inflammation and oxidative stress are key to the progressive neuronal degeneration common to chronic pathologies, traumatic injuries, and aging processes in the CNS. The proinflammatory cytokine tumor necrosis factor-alpha (TNF-α) orchestrates cellular stress by stimulating the production and release of neurotoxic mediators including reactive oxygen species (ROS). NADPH oxidases (NOX), ubiquitously expressed in all cells, have recently emerged as pivotal ROS sources in aging and disease. We demonstrated the presence of potent NOX inhibitors in wild Alaska bog blueberries partitioning discretely into a nonpolar fraction with minimal antioxidant capacity and largely devoid of polyphenols. Incubation of SH-SY5Y human neuroblastoma cells with nonpolar blueberry fractions obstructed the coalescing of lipid rafts into large domains disrupting NOX assembly therein and abolishing ROS production characteristic for TNF-α exposure. These findings illuminate nutrition-derived lipid raft modulation as a novel therapeutic approach to blunt inflammatory and oxidative stress in the aging or diseased CNS
The adsorption of helium atoms on coronene cations
We report the first experimental study of the attachment of multiple foreign
atoms to a cationic polycyclic aromatic hydrocarbon (PAH). The chosen PAH was
coronene, C24H12, which was added to liquid helium nanodroplets and then
subjected to electron bombardment. Using mass spectrometry, coronene cations
decorated with helium atoms were clearly seen and the spectrum shows peaks
with anomalously high intensities (“magic number” peaks), which represent ion-
helium complexes with added stability. The data suggest the formation of a
rigid helium layer consisting of 38 helium atoms that completely cover both
faces of the coronene ion. Additional magic numbers can be seen for the
further addition of 3 and 6 helium atoms, which are thought to attach to the
edge of the coronene. The observation of magic numbers for the addition of 38
and 44 helium atoms is in good agreement with a recent path integral Monte
Carlo prediction for helium atoms on neutral coronene. An understanding of how
atoms and molecules attach to PAH ions is important for a number of reasons
including the potential role such complexes might play in the chemistry of the
interstellar medium
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