17,226 research outputs found
A 100 micro Kelvin bolometer system for SIRTF
Progress toward a prototype of 100 mK bolometric detection system for the Space Infrared Telescope Facility (SIRTF) is described. Two adiabatic demagnetization refrigerators (ADR's) were constructed and used to investigate the capabilities necessary for orbital operation. The first, a laboratory ADR, demonstrated a hold time at 0.1 K of over 12 hours, with temperature stability approx. 3 micro-K RMS achieved by controlling the magnetic field. A durable salt pill and an efficient support system have been demonstrated. A second ADR, the SIRTF flight prototype, has been built and will be flown on a balloon. Techniques for magnetic shielding, low heat leak current leads, and a mechanical heat switch are being developed in this ADR. Plans for construction of 100 mK bolometers are discussed. Three important cosmological investigations which will be carried out by these longest wavelength SIRTF detectors are described
Development of a tailored, telehealth intervention to address chronic pain and heavy drinking among people with HIV infection: integrating perspectives of patients in HIV care.
BACKGROUND:
Chronic pain and heavy drinking commonly co-occur and can infuence the course of HIV. There have been no interventions designed to address both of these conditions among people living with HIV (PLWH), and none that have used telehealth methods. The purpose of this study was to better understand pain symptoms, patterns of alcohol use, treatment experiences, and technology use among PLWH in order to tailor a telehealth intervention that addresses these conditions
SUBJECTS:
Ten participants with moderate or greater chronic pain and heavy drinking were recruited from a cohort of patients engaged in HIV-care (Boston Alcohol Research Collaborative on HIV/AIDS Cohort) and from an integrated HIV/primary care clinic at a large urban hospital.
METHODS:
One-on-one interviews were conducted with participants to understand experiences and treatment
of HIV, chronic pain, and alcohol use. Participantsâ perceptions of the infuence of alcohol on HIV and chronic pain were explored as was motivation to change drinking. Technology use and treatment preferences were examined in the fnal section of the interview. Interviews were recorded, transcribed and uploaded into NVivoÂŽ v12 software for analysis. A codebook was developed based on interviews followed by thematic analysis in which specifc meanings were assigned to codes.
RESULTS:
A number of themes were identifed that had implications for intervention tailoring including: resilience
in coping with HIV; autonomy in health care decision-making; coping with pain, stress, and emotion; understanding treatment rationale; depression and social withdrawal; motives to drink and refrain from drinking; technology use and capacity; and preference for intervention structure and style. Ratings of intervention components indicated that participants viewed each of the proposed intervention content areas as âhelpfulâ to âvery helpfulâ. Videoconferencing was viewed as an acceptable modality for intervention delivery
CONCLUSIONS:
Results helped specify treatment targets and provided information about how to enhance intervention
delivery. The interviews supported the view that videoconferencing is an acceptable telehealth method of addressing chronic pain and heavy drinking among PLWH.UH2 AA026192 - NIAAA NIH HHSPublished versio
CCS from industrial sources
The literature concerning the application of CCS to industry is reviewed. Costs are presented for different sectors including ``high purity'' (processes which inherently produce a high concentration of CO2), cement, iron and steel, refinery and biomass. The application of CCS to industry is a field which has had much less attention than its application to the electricity production sector. Costs range from less than 2011 100/tCO 2 . In the words of a synthesis report from the United Nations Industrial Development Organisation (UNIDO) ``This area has so far not been the focus of discussions and therefore much attention needs to be paid to the application of CCS to industrial sources if the full potential of CCS is to be unlocked''
Unstable Hadrons in Hot Hadron Gas in Laboratory and in the Early Universe
We study kinetic master equations for chemical reactions involving the
formation and the natural decay of unstable particles in a thermal bath. We
consider the decay channel of one into two particles, and the inverse process,
fusion of two thermal particles into one. We present the master equations the
evolution of the density of the unstable particles in the early Universe. We
obtain the thermal invariant reaction rate using as an input the free space
(vacuum) decay time and show the medium quantum effects on reaction relaxation time. As another laboratory example
we describe the process in thermal hadronic gas in
heavy-ion collisions. A particularly interesting application of our formalism
is the process in the early Universe.
We also explore the physics of and freeze-out in the
Universe.Comment: 13 pages, 9 figures, published in Physical Review
The Evolution of Distorted Rotating Black Holes III: Initial Data
In this paper we study a new family of black hole initial data sets
corresponding to distorted ``Kerr'' black holes with moderate rotation
parameters, and distorted Schwarzschild black holes with even- and odd-parity
radiation. These data sets build on the earlier rotating black holes of Bowen
and York and the distorted Brill wave plus black hole data sets. We describe
the construction of this large family of rotating black holes. We present a
systematic study of important properties of these data sets, such as the size
and shape of their apparent horizons, and the maximum amount of radiation that
can leave the system during evolution. These data sets should be a very useful
starting point for studying the evolution of highly dynamical black holes and
can easily be extended to 3D.Comment: 16 page
Using schema transformation pathways for data lineage tracing
With the increasing amount and diversity of information available on the Internet, there has been a huge growth in information systems that need to integrate data from distributed, heterogeneous data sources. Tracing the lineage of the integrated data is one of the problems being addressed in data warehousing research. This paper presents a data lineage tracing approach based on schema transformation pathways. Our approach is not limited to one specific data model or query language, and would be useful in any data transformation/integration framework based on sequences of primitive schema transformations
Efficient Discrete Approximations of Quantum Gates
Quantum compiling addresses the problem of approximating an arbitrary quantum
gate with a string of gates drawn from a particular finite set. It has been
shown that this is possible for almost all choices of base sets and furthermore
that the number of gates required for precision epsilon is only polynomial in
log 1/epsilon. Here we prove that using certain sets of base gates quantum
compiling requires a string length that is linear in log 1/epsilon, a result
which matches the lower bound from counting volume up to constant factor.Comment: 7 pages, no figures, v3 revised to correct major error in previous
version
Fast hashing with Strong Concentration Bounds
Previous work on tabulation hashing by Patrascu and Thorup from STOC'11 on
simple tabulation and from SODA'13 on twisted tabulation offered Chernoff-style
concentration bounds on hash based sums, e.g., the number of balls/keys hashing
to a given bin, but under some quite severe restrictions on the expected values
of these sums. The basic idea in tabulation hashing is to view a key as
consisting of characters, e.g., a 64-bit key as characters of
8-bits. The character domain should be small enough that character
tables of size fit in fast cache. The schemes then use tables
of this size, so the space of tabulation hashing is . However, the
concentration bounds by Patrascu and Thorup only apply if the expected sums are
.
To see the problem, consider the very simple case where we use tabulation
hashing to throw balls into bins and want to analyse the number of
balls in a given bin. With their concentration bounds, we are fine if ,
for then the expected value is . However, if , as when tossing
unbiased coins, the expected value is for large data sets,
e.g., data sets that do not fit in fast cache.
To handle expectations that go beyond the limits of our small space, we need
a much more advanced analysis of simple tabulation, plus a new tabulation
technique that we call \emph{tabulation-permutation} hashing which is at most
twice as slow as simple tabulation. No other hashing scheme of comparable speed
offers similar Chernoff-style concentration bounds.Comment: 54 pages, 3 figures. An extended abstract appeared at the 52nd Annual
ACM Symposium on Theory of Computing (STOC20
Use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccines: Updated recommendations of the advisory committee on immunization practices - United States, 2019
The Evolution of Distorted Rotating Black Holes II: Dynamics and Analysis
We have developed a numerical code to study the evolution of distorted,
rotating black holes. This code is used to evolve a new family of black hole
initial data sets corresponding to distorted ``Kerr'' holes with a wide range
of rotation parameters, and distorted Schwarzschild black holes with odd-parity
radiation. Rotating black holes with rotation parameters as high as
are evolved and analyzed in this paper. The evolutions are generally carried
out to about , where is the ADM mass. We have extracted both the
even- and odd-parity gravitational waveforms, and find the quasinormal modes of
the holes to be excited in all cases. We also track the apparent horizons of
the black holes, and find them to be a useful tool for interpreting the
numerical results. We are able to compute the masses of the black holes from
the measurements of their apparent horizons, as well as the total energy
radiated and find their sum to be in excellent agreement with the ADM mass.Comment: 26 pages, LaTeX with RevTeX 3.0 macros. 27 uuencoded gz-compressed
postscript figures. Also available at http://jean-luc.ncsa.uiuc.edu/Papers/
Submitted to Physical Review
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