3,790 research outputs found
The Narrow-band Ultraviolet Imaging Experiment for Wide-field Surveys (NUVIEWS)-I: Dust scattered continuum
We report on the first results of the Narrow-band Ultraviolet Imaging
Experiment for Wide-field Surveys (NUVIEWS), a sounding rocket experiment
designed to map the far-ultraviolet background in four narrow bands. This is
the first imaging measurement of the UV background to cover a substantial
fraction of the sky. The narrow band responses (145, 155, 161, and 174 nm, 7-10
nm wide) allow us to isolate background contributions from dust-scattered
continuum, H2 fluorescence, and CIV 155 nm emission. In our first flight, we
mapped one quarter of the sky with 5-10 arcminute imaging resolution. In this
paper, we model the dominant contribution of the background, dust-scattered
continuum. Our data base consists of a map of over 10,000 sq. degrees with 468
independent measurements in 6.25 by 6.25 sq. degree bins. Stars and
instrumental stellar halos are removed from the data. We present a map of the
continuum background obtained in the 174 nm telescope. We use a model that
follows Witt, Friedman, and Sasseen (1997: WFS) to account for the
inhomogeneous radiation field and multiple scattering effects in clouds. We
find that the dust in the diffuse interstellar medium displays a moderate
albedo (a=0.55+/-0.1) and highly forward scattering phase function parameter
(g=0.75+/-0.1) over a large fraction of the sky, similar to dust in star
forming regions. We also have discovered a significant variance from the model.Comment: 16 pages, 3 ps figures, submitted to Astrophysical Journal Letter
Using adiabatic coupling techniques in atom-chip waveguide structures
Adiabatic techniques are well known tools in multi-level electron systems to
transfer population between different states with high fidelity. Recently it
has been realised that these ideas can also be used in ultra-cold atom systems
to achieve coherent manipulation of the atomic centre-of-mass states. Here we
present an investigation into a realistic setup using three atomic waveguides
created on top of an atom chip and show that such systems hold large potential
for the observation of adiabatic phenomena in experiments.Comment: 10 pages, 6 figures, accepted for publication in Physica Scripta for
the CEWQO2009 proceeding
Baryon Destruction by Asymmetric Dark Matter
We investigate new and unusual signals that arise in theories where dark
matter is asymmetric and carries a net antibaryon number, as may occur when the
dark matter abundance is linked to the baryon abundance. Antibaryonic dark
matter can cause {\it induced nucleon decay} by annihilating visible baryons
through inelastic scattering. These processes lead to an effective nucleon
lifetime of 10^{29}-10^{32} years in terrestrial nucleon decay experiments, if
baryon number transfer between visible and dark sectors arises through new
physics at the weak scale. The possibility of induced nucleon decay motivates a
novel approach for direct detection of cosmic dark matter in nucleon decay
experiments. Monojet searches (and related signatures) at hadron colliders also
provide a complementary probe of weak-scale dark-matter--induced baryon number
violation. Finally, we discuss the effects of baryon-destroying dark matter on
stellar systems and show that it can be consistent with existing observations.Comment: 26 pages, 6 figure
The Sweeney Legacy: A Tribute to the District Court of Maryland\u27s First Chief Judge
Many changes have been made during my first eighteen months as the Chief Judge of the District Court of Maryland. For example, we have added a brand new program to provide all indigent defendants with representation at initial appearances before Commissioners. We have also converted the judiciary from paper filing to an electronic filing and case management system and moved the location of the district court headquarters.
All of these endeavors have been challenging, but something special came when packing up the old office and moving next door. In the accumulation of folders, documents, and other miscellaneous office supplies, I found two ordinary file folders hidden amongst the many records accumulated by the district court over the years. These files, however, were anything but ordinary. What I found was not only history of the district court, but also history of its first Chief Judge – the man who sat in my position, over forty years ago. Looking through these folders that contained speeches, convocations, and publications, I not only received first-person insight to the beginnings of a new court, but of the man behind it all – the Honorable Robert F. Sweeney
Physiotherapy after arthroscopic partial meniscectomy surgery: An assessment of costs to the National Health Service, patients and society
Objectives: The purpose of this study was to determine and inform clinicians, managers, and budget allocators of the costs incurred to the British National Health Service (NHS), patient, and society when attending clinic-based physiotherapy compared with not attending clinic-based physiotherapy after arthroscopic partial meniscectomy surgery.
Methods: The valuation principle used in this study was the economic concept of opportunity cost. Costs were referred to as direct medical (NHS), direct nonmedical (patient), and indirect (societal) costs. Due to the difficulties of their measurement and valuation, intangible costs, in the form of pain and anxiety related to the effect of receiving or not receiving treatment, have not been considered in this analysis.
Results: Providing clinic-based physiotherapy after knee arthroscopic partial meniscectomy surgery is more costly to the NHS and patient, but no more costly to society than when not providing it and does not result in reduced contact with the NHS.
Conclusions: Clinic-based physiotherapy after knee arthroscopic partial meniscectomy surgery is costly and evidence is needed that its effectiveness is high enough to support its use
A resource survey of the coastal lands from Vlaming Head to Tantabiddi Well, West Cape Range region
The report comprise four parts; a brief review of the area\u27s climate, discussion of the geomorphology of the major landform units, an assessment of the potential erosion hazards of the surveyed landforms, and recommendations for development
Using Natural Experiments to Identify the Effects of SNAP on Child and Adult Health
The Supplemental Nutrition Assistance Program (SNAP; formerly known as food stamps) can have important impacts that extend beyond its intended aims to improve food security and nutrition, particularly for health and health care use. This project examined the impact of SNAP receipt and benefit level on the health of adults and children using two natural experiments to address selection bias: 1) state policy variation in SNAP in an instrumental variables (IV) analysis; and, 2) the temporary expansion of SNAP benefits and eligibility provided through the American Recovery and Reinvestment Act (ARRA) in a difference-in-difference (DD) approach. We used restricted data from the National Health Interview Survey (NHIS) from 2008 to 2014, restricting our sample to persons in SNAP-eligible and low-income SNAP-ineligible households. The IV analysis suggests that SNAP receipt is associated with improved health and reductions in foregone medical care due to affordability among adults and children. However, we find little evidence that ARRA’s temporary benefit increase led to any changes in health or health care use. Whereas SNAP receipt may improve health and health care use for populations close to the eligibility threshold (and thus induced to participate by some policies), the relatively small increase and reduction in SNAP benefits may not have been substantial enough to change health outcomes
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