986 research outputs found
Atypical one-carbon metabolism of an acetogenic and hydrogenogenic Moorella thermoacetica strain
A thermophilic spore-forming bacterium (strain AMP) was isolated from a thermophilic methanogenic bioreactor that was fed with cobalt-deprived synthetic medium containing methanol as substrate. 16S rRNA gene analysis revealed that strain AMP was closely related to the acetogenic bacterium Moorella thermoacetica DSM 521T (98.3% sequence similarity). DNA¿DNA hybridization showed 75.2 ± 4.7% similarity to M. thermoacetica DSM 521T, suggesting that strain AMP is a M. thermoacetica strain. Strain AMP has a unique one-carbon metabolism compared to other Moorella species. In media without cobalt growth of strain AMP on methanol was only sustained in coculture with a hydrogen-consuming methanogen, while in media with cobalt it grew acetogenically in the absence of the methanogen. Addition of thiosulfate led to sulfide formation and less acetate formation. Growth of strain AMP with CO resulted in the formation of hydrogen as the main product, while other CO-utilizing Moorella strains produce acetate as product. Formate supported growth only in the presence of thiosulfate or in coculture with the methanogen. Strain AMP did not grow with H2/CO2, unlike M. thermoacetica (DSM 521T). The lack of growth with H2/CO2 likely is due to the absence of cytochrome b in strain AM
Accidents Will Happen. Do Safety Systems Improve Warehouse Safety Performance?
Safety is becoming more and more an issue in warehouses. In the literature, effective measures leading to increased occupational health and safety have hardly been researched. Most research focuses on the impact of perceived safety-related leadership of managers and worker safety consciousness on ‘safety climate’ and workers’ safe behavior. We have carried out exploratory research into which measures really improve the safety performance of a warehouse. We particularly focus on the effects of (1) safety-related work procedures, (2) safety leadership, and (3) workers’ safety consciousness. Based on a survey we show that safety leadership and safety-related work procedures significantly drive worker safety consciousness, which in turn positively impacts safety performance
Tau Polarization in and
We discuss the longitudinal and transverse -polarization in inclusive
decays of hadrons containing -quarks. The calculation is performed by means
of an OPE in HQET. Some mathematical difficulties in calculating transverse
polarizations are explained. Numerical results are presented for longitudinal
and for transverse polarizations, both in and perpendicular to the decay plane.Comment: LATEX, 20 pages, 5 Postscript figure
Equilibrium solutions of the shallow water equations
A statistical method for calculating equilibrium solutions of the shallow
water equations, a model of essentially 2-d fluid flow with a free surface, is
described. The model contains a competing acoustic turbulent {\it direct}
energy cascade, and a 2-d turbulent {\it inverse} energy cascade. It is shown,
nonetheless that, just as in the corresponding theory of the inviscid Euler
equation, the infinite number of conserved quantities constrain the flow
sufficiently to produce nontrivial large-scale vortex structures which are
solutions to a set of explicitly derived coupled nonlinear partial differential
equations.Comment: 4 pages, no figures. Submitted to Physical Review Letter
A heavy quark effective field lagrangian keeping particle and antiparticle mixed sectors
We derive a tree-level heavy quark effective Lagrangian keeping
particle-antiparticle mixed sectors allowing for heavy quark-antiquark pair
annihilation and creation. However, when removing the unwanted degrees of
freedom from the effective Lagrangian one has to be careful in using the
classical equations of motion obeyed by the effective fields in order to get a
convergent expansion on the reciprocal of the heavy quark mass. Then the
application of the effective theory to such hard processes should be sensible
for special kinematic regimes as for example heavy quark pair production near
threshold.Comment: LaTeX, 14 pages, 1 EPS figure
Inclusive Semileptonic Decays in QCD Including Lepton Mass Effects
Starting from an Operator Product Expansion in the Heavy Quark Effective
Theory up to order 1/m_b^2 we calculate the inclusive semileptonic decays of
unpolarized bottom hadrons including lepton mass effects. We calculate the
differential decay spectra d\Gamma/(dE_\tau ), and the total decay rate for B
meson decays to final states containing a \tau lepton.Comment: 16 pages + 4 figs. appended in uuencoded form, LaTeX, MZ-TH/93-3
Teaching Index Numbers to economists
Economic statistics are frequently reported in the form of index numbers. This article considers how the field of Index Numbers should be approached in the teaching of a general economic degree. While the topic finds a natural home in statistics modules, it is emphasised that the area can also be referred to in the teaching of other areas of economics. It is also emphasised that the differences between Index Numbers theory and the practice of compiling economic statistics such as inflation can help students gain a better understanding of applied economic statistics. Methods for assessing learning in the area are also considered and available material to support teaching is also summarised
The Promising Process to Distinguish Supersymmetric Models with Large tan from the Standard Model:
It is shown that in supersymmetric models (SUSYMs) the large supersymmetric
contributions to come from the Feynman diagrams
which consist of exchanging neutral Higgs bosons (NHBs) and the chargino-stop
loop and are proportional to tan when tan
is large and the mass of the lightest neutral Higgs boson m is not too
large (say, less than 150 Gev). Numerical results show that the branching
ratios of can be enhanced by more than 100%
compared to the standard model (SM) and the backward-forward asymmetry of
lepton is significantly different from that in SM when tan.Comment: 8 pages, including 2 figure
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Cognitive tests used in chronic adult human randomised controlled trial micronutrient and phytochemical intervention studies
In recent years there has been a rapid growth of interest in exploring the relationship between nutritional therapies and the maintenance of cognitive function in adulthood. Emerging evidence reveals an increasingly complex picture with respect to the benefits of various food constituents on learning, memory and psychomotor function in adults. However, to date, there has been little consensus in human studies on the range of cognitive domains to be tested or the particular tests to be employed. To illustrate the potential difficulties that this poses, we conducted a systematic review of existing human adult randomised controlled trial (RCT) studies that have investigated the effects of 24 d to 36 months of supplementation with flavonoids and micronutrients on cognitive performance. There were thirty-nine studies employing a total of 121 different cognitive tasks that met the criteria for inclusion. Results showed that less than half of these studies reported positive effects of treatment, with some important cognitive domains either under-represented or not explored at all. Although there was some evidence of sensitivity to nutritional supplementation in a number of domains (for example, executive function, spatial working memory), interpretation is currently difficult given the prevailing 'scattergun approach' for selecting cognitive tests. Specifically, the practice means that it is often difficult to distinguish between a boundary condition for a particular nutrient and a lack of task sensitivity. We argue that for significant future progress to be made, researchers need to pay much closer attention to existing human RCT and animal data, as well as to more basic issues surrounding task sensitivity, statistical power and type I error
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