28,996 research outputs found
USAF solar thermal applications overview
Process heat applications were compared to solar thermal technologies. The generic process heat applications were analyzed for solar thermal technology utilization, using SERI's PROSYS/ECONOMAT model in an end use matching analysis and a separate analysis was made for solar ponds. Solar technologies appear attractive in a large number of applications. Low temperature applications at sites with high insolation and high fuel costs were found to be most attractive. No one solar thermal technology emerges as a clearly universal or preferred technology, however,, solar ponds offer a potential high payoff in a few, selected applications. It was shown that troughs and flat plate systems are cost effective in a large number of applications
Constraints on radiative decay of the 17-keV neutrino from COBE Measurements
It is shown that, for a nontrivial radiative decay channel of the 17-keV
neutrino, the photons would distort the microwave background radiation through
ionization of the universe. The constraint on the branching ratio of such
decays from COBE measurements is found to be more stringent than that from
other considerations. The limit on the branching ratio in terms of the Compton
parameter is for an
universe.Comment: 7 pages. (figures will be sent on request) (To appear in Phys. Rev.
D.
Low-power radio galaxy environments in the Subaru/XMM-Newton Deep Field at z~0.5
We present multi-object spectroscopy of galaxies in the immediate (Mpc-scale)
environments of four low-power (L_1.4 GHz < 10^25 W/Hz) radio galaxies at
z~0.5, selected from the Subaru/XMM-Newton Deep Field. We use the spectra to
calculate velocity dispersions and central redshifts of the groups the radio
galaxies inhabit, and combined with XMM-Newton (0.3-10 keV) X-ray observations
investigate the L_X--sigma_v and T_X--sigma_v scaling relationships. All the
radio galaxies reside in moderately rich groups -- intermediate environments
between poor groups and rich clusters, with remarkably similar X-ray
properties. We concentrate our discussion on our best statistical example that
we interpret as a low-power (FRI) source triggered within a sub-group, which in
turn is interacting with a nearby group of galaxies, containing the bulk of the
X-ray emission for the system -- a basic scenario which can be compared to more
powerful radio sources at both high (z>4) and low (z<0.1) redshifts. This
suggests that galaxy-galaxy interactions triggered by group mergers may play an
important role in the life-cycle of radio galaxies at all epochs and
luminosities.Comment: 12 pages, 7 figures, accepted for publication in MNRAS. High
resolution version available upon reques
Two quantum Simpson's paradoxes
The so-called Simpson's "paradox", or Yule-Simpson (YS) effect, occurs in
classical statistics when the correlations that are present among different
sets of samples are reversed if the sets are combined together, thus ignoring
one or more lurking variables. Here we illustrate the occurrence of two
analogue effects in quantum measurements. The first, which we term
quantum-classical YS effect, may occur with quantum limited measurements and
with lurking variables coming from the mixing of states, whereas the second,
here referred to as quantum-quantum YS effect, may take place when coherent
superpositions of quantum states are allowed. By analyzing quantum measurements
on low dimensional systems (qubits and qutrits), we show that the two effects
may occur independently, and that the quantum-quantum YS effect is more likely
to occur than the corresponding quantum-classical one. We also found that there
exist classes of superposition states for which the quantum-classical YS effect
cannot occur for any measurement and, at the same time, the quantum-quantum YS
effect takes place in a consistent fraction of the possible measurement
settings. The occurrence of the effect in the presence of partial coherence is
discussed as well as its possible implications for quantum hypothesis testing.Comment: published versio
Tempo and Mode of Evolution in the Tangled Nature Model
We study the Tangled Nature model of macro evolution and demonstrate that the
co-evolutionary dynamics produces an increasingly correlated core of well
occupied types. At the same time the entire configuration of types becomes
increasing de-correlated. This finding is related to ecosystem evolution. The
systems level dynamics of the model is subordinated to intermittent transitions
between meta-stable states. We improve on previous studies of the statistics of
the transition times and show that the fluctuations in the offspring
probability decreases with number of transitions. The longtime adaptation, as
seen by an increasing population size is demonstrated to be related to the
convexity of the offspring probability. We explain how the models behaviour is
a mathematical reflection of Darwin's concept of adaptation of profitable
variations.Comment: 6 pages, 5 figure
Illuminating dark matter and primordial black holes with interstellar antiprotons
Interstellar antiproton fluxes can arise from dark matter annihilating or
decaying into quarks or gluons that subsequently fragment into antiprotons.
Evaporation of primordial black holes also can produce a significant antiproton
cosmic-ray flux. Since the background of secondary antiprotons from spallation
has an interstellar energy spectrum that peaks at \sim 2\gev and falls
rapidly for energies below this, low-energy measurements of cosmic antiprotons
are useful in the search for exotic antiproton sources. However, measurement of
the flux near the earth is challenged by significant uncertainties from the
effects of the solar wind. We suggest evading this problem and more effectively
probing dark-matter signals by placing an antiproton spectrometer aboard an
interstellar probe currently under discussion. We address the experimental
challenges of a light, low-power-consuming detector, and present an initial
design of such an instrument. This experimental effort could significantly
increase our ability to detect, and have confidence in, a signal of exotic,
nonstandard antiproton sources. Furthermore, solar modulation effects in the
heliosphere would be better quantified and understood by comparing results to
inverse modulated data derived from existing balloon and space-based detectors
near the earth.Comment: 18 pages, 3 figure
National survey of the prevalence, incidence, primary care burden, and treatment of heart failure in Scotland
Objective: To examine the epidemiology, primary care burden, and treatment of heart failure in Scotland, UK.
Design: Cross sectional data from primary care practices participating in the Scottish continuous morbidity recording scheme between 1 April 1999 and 31 March 2000.
Setting: 53 primary care practices (307 741 patients).
Subjects: 2186 adult patients with heart failure.
Results: The prevalence of heart failure in Scotland was 7.1 in 1000, increasing with age to 90.1 in 1000 among patients 85 years. The incidence of heart failure was 2.0 in 1000, increasing with age to 22.4 in 1000 among patients 85 years. For older patients, consultation rates for heart failure equalled or exceeded those for angina and hypertension. Respiratory tract infection was the most common co-morbidity leading to consultation. Among men, 23% were prescribed a ß blocker, 11% spironolactone, and 46% an angiotensin converting enzyme inhibitor. The corresponding figures for women were 20% (p = 0.29 versus men), 7% (p = 0.02), and 34% (p < 0.001). Among patients < 75 years 26% were prescribed a β blocker, 11% spironolactone, and 50% an angiotensin converting enzyme inhibitor. The corresponding figures for patients 75 years were 19% (p = 0.04 versus patients < 75), 7% (p = 0.04), and 33% (p < 0.001).
Conclusions: Heart failure is a common condition, especially with advancing age. In the elderly, the community burden of heart failure is at least as great as that of angina or hypertension. The high rate of concomitant respiratory tract infection emphasises the need for strategies to immunise patients with heart failure against influenza and pneumococcal infection. Drugs proven to improve survival in heart failure are used less frequently for elderly patients and women
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Peer support for discharge from inpatient to community mental health services: Study protocol clinical trial (SPIRIT Compliant).
INTRODUCTION: In the period shortly after discharge from inpatient to community mental health care, people are at increased risk of self-harm, suicide, and readmission to hospital. Discharge interventions including peer support have shown potential, and there is some evidence that community-based peer support reduces readmissions. However, systematic reviews of peer support in mental health services indicate poor trial quality and a lack of reporting of how peer support is distinctive from other mental health support. This study is designed to establish the clinical and cost effectiveness of a peer worker intervention to support discharge from inpatient to community mental health care, and to address issues of trial quality and clarity of reporting of peer support interventions. METHODS: This protocol describes an individually randomized controlled superiority trial, hypothesizing that people offered a peer worker discharge intervention in addition to usual follow-up care in the community are less likely to be readmitted in the 12 months post discharge than people receiving usual care alone. A total of 590 people will be recruited shortly before discharge from hospital and randomly allocated to care as usual plus the peer worker intervention or care as usual alone. Manualized peer support provided by trained peer workers begins in hospital and continues for 4 months in the community post discharge. Secondary psychosocial outcomes are assessed at 4 months post discharge, and service use and cost outcomes at 12 months post discharge, alongside a mixed methods process evaluation. DISCUSSION: Clearly specified procedures for sequencing participant allocation and for blinding assessors to allocation, plus full reporting of outcomes, should reduce risk of bias in trial findings and contribute to improved quality in the peer support evidence base. The involvement of members of the study team with direct experience of peer support, mental distress, and using mental health services, in coproducing the intervention and designing the trial, ensures that we theorize and clearly describe the peer worker intervention, and evaluate how peer support is related to any change in outcome. This is an important methodological contribution to the evidence base. TRIAL REGISTRATION: This study was prospectively registered as ISRCTN 10043328 on November 28, 2016
Skew in ovarian activation depends on domicile size in phyllode-glueing thrips
Costs and benefits of group living are a fundamental topic in behavioural ecology. Resource availability affects individuals’ breeding prospects alone and in groups, as well as how reproduction is distributed within groups (“reproductive skew”). Here, we provide correlational evidence in facultatively social thrips that breeding resources are associated with (1) whether solitary or social living is favoured, and (2) the degree of ovarian skew. Dunatothrips aneurae (Thysanoptera, Phlaeothripidae) cooperatively build silk “domiciles” on Australian Acacias, feeding exclusively from internal phyllode surfaces. Per capita productivity scaled differently with group size depending on domicile volume - females in small domiciles did better alone than in groups, whereas in large domiciles single and group-nesting females did equally well. Ovarian dissections revealed that in small domiciles some females were nonreproductive, indicating ovarian (i.e. reproductive) skew. Skew increased as domicile size decreased and group size increased. Breeders had smaller oocyte volume in smaller domiciles, especially those containing nonreproductives. These findings suggest group formation and reproductive skew in D. aneurae may be influenced by reproductive competition for breeding resources. Nonreproductive females in small domiciles may be reproductively suppressed, subfertile, or accumulating resources to reproduce
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