2,202 research outputs found
The Supersymmetric Origin of Matter
The Minimal Supersymmetric extension of the Standard Model (MSSM) can provide
the correct neutralino relic abundance and baryon number asymmetry of the
universe. Both may be efficiently generated in the presence of CP violating
phases, light charginos and neutralinos, and a light top squark. Due to the
coannihilation of the neutralino with the light stop, we find a large region of
parameter space in which the neutralino relic density is consistent with WMAP
and SDSS data. We perform a detailed study of the additional constraints
induced when CP violating phases, consistent with the ones required for
baryogenesis, are included. We explore the possible tests of this scenario from
present and future electron Electric Dipole Moment (EDM) measurements, direct
neutralino detection experiments, collider searches and the b -> s gamma decay
rate. We find that the EDM constraints are quite severe and that electron EDM
experiments, together with stop searches at the Tevatron and Higgs searches at
the LHC, will provide a definite test of our scenario of electroweak
baryogenesis in the next few years.Comment: 30 pages, 14 figure
GrameneMart: the BioMart data portal for the Gramene project
Gramene is a well-established resource for plant comparative genome analysis. Data are generated through automated and curated analyses and made available through web interfaces such as GrameneMart. The Gramene project was an early adopter of the BioMart software, which remains an integral and well-used component of the Gramene website. BioMart accessible data sets include plant gene annotations, plant variation catalogues, genetic markers, physical mapping entities, public DNA/mRNA sequences of various types and curated quantitative trait loci for various species. Database URL: http://www.gramene.org/biomart/martview
High Consequence Safety Research and Policy: The US Airline Application
The implementation of safety programs in Flight Operations has been successful since the Federal Aviation Administration formally introduced Safety Management Systems (SMS) procedures in 2000. The addition of safety programs like SMS into aviation organizations has been confirmed to improve safety culture, communication, and overall hazard mitigation. This research explores the changes and improvements that are made in maintenance programs where an SMS is formally implemented. In the United States it is legal for children under the age of twenty-four months to fly in commercial aircraft on the lap of a parent or guardian, while being unsecured or unrestrained. Throughout the history of aviation safety there have been no improvements, regulations, or laws put in place to ensure the safety of our Nation’s youngest fliers. The Policy Research Construct (PRC) will be used as a proposal for the development of advocacy for regulatory change. Through Policy Research, recommendations can be made to improve safety and create formal regulatory changes to make SMS mandatory in all aviation maintenance programs operating within the United States.
The student authors are affiliated with the Department of Safety in the College of Aviation at Embry-Riddle Aeronautical University in Prescott, AZ. Tori Kobayashi is a graduate student in the MS Safety Science program. Calissa Spooner is an undergraduate student in the Industrial Psychology and Safety program
Measurements of Scintillation Efficiency and Pulse-Shape for Low Energy Recoils in Liquid Xenon
Results of observations of low energy nuclear and electron recoil events in
liquid xenon scintillator detectors are given. The relative scintillation
efficiency for nuclear recoils is 0.22 +/- 0.01 in the recoil energy range 40
keV - 70 keV. Under the assumption of a single dominant decay component to the
scintillation pulse-shape the log-normal mean parameter T0 of the maximum
likelihood estimator of the decay time constant for 6 keV < Eee < 30 keV
nuclear recoil events is equal to 21.0 ns +/- 0.5 ns. It is observed that for
electron recoils T0 rises slowly with energy, having a value ~ 30 ns at Eee ~
15 keV. Electron and nuclear recoil pulse-shapes are found to be well fitted by
single exponential functions although some evidence is found for a double
exponential form for the nuclear recoil pulse-shape.Comment: 11 pages, including 5 encapsulated postscript figure
Attitudes of Canadian Beef Producers Toward Animal Welfare
Commercial beef production in western Canada involves raising cows and calves on large tracts of grassland, plus grain-based ‘finishing’ of animals in outdoor feedlots. This study used open-ended, semi-structured interviews to explore views on animal welfare of 23 commercial beef producers in this system. Although wary of the term ‘animal welfare’, participants understood the concept to encompass three well-known elements: (i) basic animal health and body condition; (ii) affective states (comfort, contentment, freedom from hunger or thirst); and (iii) the ability to live a ‘natural’ life. Participants attached importance to protecting animals from natural hardships (extreme weather, predators), yet many regarded some degree of natural challenge as acceptable or even positive. Quiet rumination was uniformly regarded as indicating contentment. Avoiding ‘stress’ was seen as a central goal, to be achieved especially by skilful handling and good facilities. Invasive procedures (branding, castration, de-horning) were recognised as painful but were accepted because they were seen as: (i) necessary for regulatory or management reasons; (ii) satisfactory trade-offs to prevent worse welfare problems such as aggression; or (iii) sufficiently short-term to be relatively unimportant. Other issues — including poor facilities, rough or excessive handling, poor nutrition, and failure to protect health — were regarded as more serious welfare concerns. While feeling constrained by low profits, participants saw good welfare as crucial to profitability. Participants uniformly expressed an ethic of care, enjoyment of working with animals, and varying degrees of willingness to sacrifice personal comfort for animal well-being. We argue that animal welfare policy and advocacy are likely to be more successful in engaging producers if they acknowledge and address producers’ views on animal welfare
Graph reasoning with context-aware linearization for interpretable fact extraction and verification
This paper presents an end-to-end system for fact extraction and verification using textual and tabular evidence, the performance of which we demonstrate on the FEVEROUS dataset. We experiment with both a multi-task learning paradigm to jointly train a graph attention network for both the task of evidence extraction and veracity prediction, as well as a single objective graph model for solely learning veracity prediction and separate evidence extraction. In both instances, we employ a framework for per-cell linearization of tabular evidence, thus allowing us to treat evidence from tables as sequences. The templates we employ for linearizing tables capture the context as well as the content of table data. We furthermore provide a case study to show the interpretability our approach. Our best performing system achieves a FEVEROUS score of 0.23 and 53% label accuracy on the blind test data
The DRIFT Project: Searching for WIMPS with a Directional Detector
A low pressure time projection chamber for the detection of WIMPs is
discussed. Discrimination against Compton electron background in such a device
should be very good, and directional information about the recoil atoms would
be obtainable. If a full 3-D reconstruction of the recoil tracks can be
achieved, Monte Carlo studies indicate that a WIMP signal could be identified
with high confidence from as few as 30 detected WIMP-nucleus scattering events.Comment: 5 pages, 3 figures. Presented at Dark 98, Heidelberg, July 1998, and
to appear in conference proceeding
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