9,667 research outputs found
The evolution and decay of supersymmetric flat directions in the early universe and their role in thermalizing the universe
I study the post-inflation oscillation and decay of light coherent scalar
field condensates that may develop during an inflationary phase of the
universe. In particular, the light scalars studied are a composition of the
scalar particles of a supersymmetric theory which correspond to the flat
directions of the theory's scalar potential. Some toy models that possess
supersymmetric flat directions are presented and numerical solutions for the
evolution of the scalar fields are obtained. Both analytic and numeric results
suggest that such condensates, if they existed in the early universe, can decay
through a rapid and nonperturbative process long before these condensates could
significantly affect the thermalization of the universe.Comment: 193 Pages, Ph. D. Thesi
The accident risk of motorcyclists
This report contains the findings of a study to explore and quantify the interacting influences which determine motorcyclist accident liabilities. It was conducted on behalf of Road Safety Division, Department for Transport. The study first reviewed existing data sources to investigate the trends in motorcycling accidents over the last decade or so. The main part of the study was to carry out a survey of nearly 30,000 current motorcyclists in order to explore the relationship between accident risk and variables such as annual mileage, age, experience, journey type, training, personal characteristics of the riders, and the self-reported behaviours and attitudes of the riders. The numbers of accidents reported by riders within the past 12-months of riding were modelled using generalised linear techniques to take into account factors such as mileage, age, experience, bike size and the conditions prevailing when they rode. Models of rider behaviour were developed using other statistical modelling techniques. These models investigated how attitudes/motivations/perceptions and rider style influence rider behaviour, and how rider behaviour influences the likelihood of accident involvement. The influence of age, sex and experience on attitudes and behaviours, and as direct or indirect influences on accidents were also investigated. Accident risk was also directly influenced by the number of miles ridden in the past 12-months. The report makes a number of recommendations for improving the safety of motorcycle riders
Crew systems and flight station concepts for a 1995 transport aircraft
Aircraft functional systems and crew systems were defined for a 1995 transport aircraft through a process of mission analysis, preliminary design, and evaluation in a soft mockup. This resulted in a revolutionary pilot's desk flight station design featuring an all-electric aircraft, fly-by-wire/light flight and thrust control systems, large electronic color head-down displays, head-up displays, touch panel controls for aircraft functional systems, voice command and response systems, and air traffic control systems projected for the 1990s. The conceptual aircraft, for which crew systems were designed, is a generic twin-engine wide-body, low-wing transport, capable of worldwide operation. The flight control system consists of conventional surfaces (some employed in unique ways) and new surfaces not used on current transports. The design will be incorporated into flight simulation facilities at NASA-Langley, NASA-Ames, and the Lockheed-Georgia Company. When interfaced with advanced air traffic control system models, the facilities will provide full-mission capability for researching issues affecting transport aircraft flight stations and crews of the 1990s
A new approach to grain insect control
Western Australian farmers now have a legal responsibility to control stored grain insects on their farms.
Ten species of insects, usually referred to collectively as \u27weevils\u27, have been \u27declared\u27 under the Agriculture and Related Resources Act.
In Western Australia, grain storage insects are not found in standing cereal crops. Thus, it should be possible to set up a clean delivery pipeline from the paddock to the C.B.H. bin
Numerical Evidence for the Observation of a Scalar Glueball
We compute from lattice QCD in the valence (quenched) approximation the
partial decay widths of the lightest scalar glueball to pairs of pseudoscalar
quark-antiquark states. These predictions and values obtained earlier for the
scalar glueball's mass are in good agreement with the observed properties of
and inconsistent with all other observed meson resonances.Comment: 12 pages of Latex, 3 PostsScript figures as separate uufil
Towards the glueball spectrum of full QCD
We present first results on masses of the scalar and tensor glueballs as well
as of the torelon from simulations of QCD with two light flavours of Wilson
fermions. The gauge configurations of extent 16^3*32 at beta = 5.6 and kappa =
0.156, 0.157 and 0.1575 have been generated as part of the SESAM collaboration
programme. The present lattice resolutions correspond to 1/a = 2.0-2.3 GeV and
ratios m(pi)/m(rho) = 0.83, 0.76 and 0.71, respectively. Studies on larger
lattice volumes and closer to the chiral limit are in progress.Comment: 4 pages, LaTeX, espcrc2 and epsf styles required, 4 epsf figures,
poster presented by G. Bali at Lattice '9
On the Dynamics of Light Quarks in QCD
We describe recent results concerning the behavior of lattice QCD with light
dynamical Wilson and Staggered quarks. We show that it is possible to reach
regions of parameter space with light pions using Wilson
fermions. If the Hybrid Molecular Dynamics (HMD) algorithm is used with the
same parameters it gives incorrect results. We also present preliminary results
using a higher-order integration scheme.Comment: 4 pages (all in postscript), proceedings of LAT'9
Single Event Effects in the Pixel readout chip for BTeV
In future experiments the readout electronics for pixel detectors is required
to be resistant to a very high radiation level. In this paper we report on
irradiation tests performed on several preFPIX2 prototype pixel readout chips
for the BTeV experiment exposed to a 200 MeV proton beam. The prototype chips
have been implemented in commercial 0.25 um CMOS processes following radiation
tolerant design rules. The results show that this ASIC design tolerates a large
total radiation dose, and that radiation induced Single Event Effects occur at
a manageable level.Comment: 15 pages, 6 Postscript figure
The Effect of Dietary Supplementation with Spent Cider Yeast on the Swine Distal Gut Microbiome
peer-reviewedBackground: There is an increasing need for alternatives to antibiotics for promoting animal health, given the increasing
problems associated with antibiotic resistance. In this regard, we evaluated spent cider yeast as a potential probiotic for
modifying the gut microbiota in weanling pigs using pyrosequencing of 16S rRNA gene libraries.
Methodology and Principal Findings: Piglets aged 24–26 days were assigned to one of two study groups; control (n = 12)
and treatment (n = 12). The control animals were fed with a basal diet and the treatment animals were fed with basal diet in
combination with cider yeast supplement (500 ml cider yeast containing ,7.6 log CFU/ml) for 21 days. Faecal samples were
collected for 16s rRNA gene compositional analysis. 16S rRNA compositional sequencing analysis of the faecal samples
collected from day 0 and day 21 revealed marked differences in microbial diversity at both the phylum and genus levels
between the control and treatment groups. This analysis confirmed that levels of Salmonella and Escherichia were
significantly decreased in the treatment group, compared with the control (P,0.001). This data suggest a positive influence
of dietary supplementation with live cider yeast on the microbial diversity of the pig distal gut.
Conclusions/Significance: The effect of dietary cider yeast on porcine gut microbial communities was characterized for the
first time using 16S rRNA gene compositional sequencing. Dietary cider yeast can potentially alter the gut microbiota,
however such changes depend on their endogenous microbiota that causes a divergence in relative response to that given
diet.This work was funded by Enterprise Ireland, under the Commercialisation Fund (Contract No: CFTD/05/117), the Irish Government under the National
Development Plan, 2000–2006, the European Research and Development Fund and Science Foundation Ireland (SFI).European Research and Development Fun
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