2,016 research outputs found
Supersymmetry with radiatively-driven naturalness: implications for WIMP and axion searches
By insisting on naturalness in both the electroweak and QCD sectors of the
MSSM, the portrait for dark matter production is seriously modified from the
usual WIMP miracle picture. In SUSY models with radiatively-driven naturalness
(radiative natural SUSY or RNS) which include a DFSZ-like solution to the
strong CP and SUSY mu problems, dark matter is expected to be an admixture of
both axions and higgsino-like WIMPs. The WIMP/axion abundance calculation
requires simultaneous solution of a set of coupled Boltzmann equations which
describe quasi-stable axinos and saxions. In most of parameter space, axions
make up the dominant contribution of dark matter although regions of WIMP
dominance also occur. We show the allowed range of PQ scale f_a and compare to
the values expected to be probed by the ADMX axion detector in the near future.
We also show WIMP detection rates which are suppressed from usual expectations
because now WIMPs comprise only a fraction of the total dark matter.
Nonetheless, ton-scale noble liquid detectors should be able to probe the
entirety of RNS parameter space. Indirect WIMP detection rates are less
propitious since they are reduced by the square of the depleted WIMP abundance.Comment: 25 pages with 14 .png figures; submitted to special issue
"Supersymmetry and Dark Matter" in Symmetry, edited by D. Clin
Carina OB Stars: X-ray Signatures of Wind Shocks and Magnetic Fields
The Chandra Carina Complex contains 200 known O- and B type stars. The
Chandra survey detected 68 of the 70 O stars and 61 of 127 known B0-B3 stars.
We have assembled a publicly available optical/X-ray database to identify OB
stars that depart from the canonical Lx/Lbol relation, or whose average X-ray
temperatures exceed 1 keV. Among the single O stars with high kT we identify
two candidate magnetically confined wind shock sources: Tr16-22, O8.5 V, and LS
1865, O8.5 V((f)). The O4 III(fc) star HD 93250 exhibits strong, hard, variable
X-rays, suggesting it may be a massive binary with a period of >30 days. The
visual O2 If* binary HD 93129A shows soft 0.6 keV and hard 1.9 keV emission
components, suggesting embedded wind shocks close to the O2 If* Aa primary, and
colliding wind shocks between Aa and Ab. Of the 11 known O-type spectroscopic
binaries, the long orbital-period systems HD 93343, HD 93403 and QZ Car have
higher shock temperatures than short-period systems such as HD 93205 and FO 15.
Although the X-rays from most B stars may be produced in the coronae of unseen,
low-mass pre-main-sequence companions, a dozen B stars with high Lx cannot be
explained by a distribution of unseen companions. One of these, SS73 24 in the
Treasure Chest cluster, is a new candidate Herbig Be star.Comment: To be published in a special issue of the Astrophysical Journal
Supplement on the Chandra Carina Complex Projec
Information Discovery on Electronic Health Records Using Authority Flow Techniques
<p>Abstract</p> <p>Background</p> <p>As the use of electronic health records (EHRs) becomes more widespread, so does the need to search and provide effective information discovery within them. Querying by keyword has emerged as one of the most effective paradigms for searching. Most work in this area is based on traditional Information Retrieval (IR) techniques, where each document is compared individually against the query. We compare the effectiveness of two fundamentally different techniques for keyword search of EHRs.</p> <p>Methods</p> <p>We built two ranking systems. The traditional BM25 system exploits the EHRs' content without regard to association among entities within. The Clinical ObjectRank (CO) system exploits the entities' associations in EHRs using an authority-flow algorithm to discover the most relevant entities. BM25 and CO were deployed on an EHR dataset of the cardiovascular division of Miami Children's Hospital. Using sequences of keywords as queries, sensitivity and specificity were measured by two physicians for a set of 11 queries related to congenital cardiac disease.</p> <p>Results</p> <p>Our pilot evaluation showed that CO outperforms BM25 in terms of sensitivity (65% vs. 38%) by 71% on average, while maintaining the specificity (64% vs. 61%). The evaluation was done by two physicians.</p> <p>Conclusions</p> <p>Authority-flow techniques can greatly improve the detection of relevant information in EHRs and hence deserve further study.</p
Surface Nano-structured Coating for Improved Performance of Axial Piston Pumps
The work starts from the consideration that most of the power losses in a hydraulic pump is due to frictional losses made by the relative motion between moving parts. This fact is particularly true at low operating velocities, when the hydraulic lift effect must be able to maintain a minimum clearance in meatus to limit the volumetric losses. The potential of structured coatings at nanoscale, with super-hydrophobic and oleophobic characteristics, has never been exploited before in an industrial application. The work studies the potential application of nano-coating on piston slippers surface in a real industrial case. The aim is to develop a new industrial solution to increase the energetic efficiency of hydraulic pump used in earthmoving machines. The proposed solution is investigated using a dedicated test bench, designed to reproduce real working conditions of the pump. The results showa reduction of friction coefficient while changing working pressure and rotation velocity
Light and flow regimes regulate the metabolism of rivers
Mean annual temperature and mean annual precipitation drive much of the variation in productivity across Earth's terrestrial ecosystems but do not explain variation in gross primary productivity (GPP) or ecosystem respiration (ER) in flowing waters. We document substantial variation in the magnitude and seasonality of GPP and ER across 222 US rivers. In contrast to their terrestrial counterparts, most river ecosystems respire far more carbon than they fix and have less pronounced and consistent seasonality in their metabolic rates. We find that variation in annual solar energy inputs and stability of flows are the primary drivers of GPP and ER across rivers. A classification schema based on these drivers advances river science and informs management.We thank Ted Stets, Jordan Read, Tom Battin, Sophia
Bonjour, Marina Palta, and members of the Duke River Center for their help in
developing these ideas. This work was supported by grants from the NSF
1442439 (to E.S.B. and J.W.H.), 1834679 (to R.O.H.), 1442451 (to R.O.H.),
2019528 (to R.O.H. and J.R.B.), 1442140 (to M.C.), 1442451 (to A.M.H.),
1442467 (to E.H.S.), 1442522 (to N.B.G.), 1624807 (to N.B.G.), and US Geological
Survey funding for the working group was supported by the John Wesley
Power Center for Analysis and Synthesis. Phil Savoy contributed as a postdoc-
toral associate at Duke University and as a postdoctoral associate (contractor)
at the US Geological Survey
Implanted Satellite Transmitters Affect Sea Duck Movement Patterns at Short and Long Timescales
Studies of the effects of transmitters on wildlife often focus on survival. However, sublethal behavioral changes resulting from radio-marking have the potential to affect inferences from telemetry data and may vary based on individual and environmental characteristics. We used a long-term, multi-species tracking study of sea ducks to assess behavioral patterns at multiple temporal scales following implantation of intracoelomic satellite transmitters. We applied state-space models to assess short-term behavioral patterns in 476 individuals with implanted satellite transmitters, as well as comparing breeding site attendance and migratory phenology across multiple years after capture. In the short term, our results suggest an increase in dispersive behavior immediately following capture and transmitter implantation; however, behavior returned to seasonally average patterns within ~5 days after release. Over multiple years, we found that breeding site attendance by both males and females was depressed during the first breeding season after radio-marking relative to subsequent years, with larger relative decreases in breeding site attendance among males than females. We also found that spring and breeding migrations occurred later in the first year after radio-marking than in subsequent years. Across all behavioral effects, the severity of behavioral change often varied by species, sex, age, and capture season. We conclude that, although individuals appear to adjust relatively quickly (i.e. within 1 week) to implanted satellite transmitters, changes in breeding phenology may occur over the longer term and should be considered when analyzing and reporting telemetry data
Spatially Explicit Network Analysis Reveals Multi‐Species Annual Cycle Movement Patterns of Sea Ducks
Conservation of long‐distance migratory species poses unique challenges. Migratory connectivity, that is, the extent to which groupings of individuals at breeding sites are maintained in wintering areas, is frequently used to evaluate population structure and assess use of key habitat areas. However, for species with complex or variable annual cycle movements, this traditional bimodal framework of migratory connectivity may be overly simplistic. Like many other waterfowl, sea ducks often travel to specific pre‐ and post‐breeding sites outside their nesting and wintering areas to prepare for migration by feeding extensively and, in some cases, molting their flight feathers. These additional migrations may play a key role in population structure, but are not included in traditional models of migratory connectivity. Network analysis, which applies graph theory to assess linkages between discrete locations or entities, offers a powerful tool for quantitatively assessing the contributions of different sites used throughout the annual cycle to complex spatial networks. We collected satellite telemetry data on annual cycle movements of 672 individual sea ducks of five species from throughout eastern North America and the Great Lakes. From these data, we constructed a multi‐species network model of migratory patterns and site use over the course of breeding, molting, wintering, and migratory staging. Our results highlight inter‐ and intra‐specific differences in the patterns and complexity of annual cycle movement patterns, including the central importance of staging and molting sites in James Bay, the St. Lawrence River, and southern New England to multi‐species annual cycle habitat linkages, and highlight the value of Long‐tailed Ducks (Calengula haemalis) as an umbrella species to represent the movement patterns of multiple sea duck species. We also discuss potential applications of network migration models to conservation prioritization, identification of population units, and integrating different data streams
Measurement of the prompt J/psi and psi(2S) polarizations in pp collisions at sqrt(s) = 7 TeV
The polarizations of prompt J/psi and psi(2S) mesons are measured in proton-proton collisions at sqrt(s) = 7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 inverse femtobarns. The prompt J/psi and psi(2S) polarization parameters lambda[theta], lambda[phi], and lambda[theta, phi], as well as the frame-invariant quantity lambda(tilde), are measured from the dimuon decay angular distributions in three different polarization frames. The J/psi results are obtained in the transverse momentum range 14 < pt < 70 GeV, in the rapidity intervals abs(y) < 0.6 and 0.6 < abs(y) < 1.2. The corresponding psi(2S) results cover 14 < pt < 50 GeV and include a third rapidity bin, 1.2 < abs(y) < 1.5. No evidence of large transverse or longitudinal polarizations is seen in these kinematic regions, which extend much beyond those previously explored
Schadevergoeding bij overlijden: een stoel die een soort tafeltje is
In het aansprakelijkheidsrecht heeft een benadeelde in beginsel recht op volledige vergoeding van zijn schade. De gevolgen van de schadetoebrengende gebeurtenis dienen zoveel als mogelijk te worden weggenomen of te worden gecompenseerd. Daarbij wordt gekeken naar de situatie waarin de benadeelde zou hebben verkeerd indien de schadetoebrengende gebeurtenis niet zou hebben plaatsgevonden. Dat is bij overlijden per definitie problematisch. Er is iemand weggevallen, wat vele gevolgen heeft. De schade als gevolg van het overlijden komt maar beperkt voor vergoeding in aanmerking. In artikel 6:108 BW is een drietal beperkingen te vinden. Het gaat hier om beperkingen ten aanzien van de aard van de schade, de kring van gerechtigden en de omvang van de schade. Daarbij hinkt het recht op schadevergoeding bij overlijden op twee gedachten. Aan de ene kant is er het aansprakelijkheidsrecht, maar de geleden schade komt niet volledig voor vergoeding in aanmerking. Aan de andere kant is er het recht op alimentatie uit het familierecht, maar dat wordt bij overlijden niet consequent toegepast. De motieven voor de beperkingen van het recht op schadevergoeding zijn achterhaald en niet (langer) overtuigend. Het recht is niet bij de tijd, het sluit niet aan bij de maatschappelijke ontwikkelingen. De beperkingen die het recht op schadevergoeding bij overlijden in de huidige samenleving met zich meebrengt zorgen voor complexe methoden om de nabestaanden tegemoet te komen en oogsten daardoor veel kritiek. In deze bijdrage wordt die kritiek besproken. De bijdrage wordt afgesloten met enkele denkrichtingen voor nader onderzoek
Measurement of the Tau Lepton Polarisation at LEP2
A first measurement of the average polarisation P_tau of tau leptons produced in e+e- annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P_tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV.A first measurement of the average polarisation Pτ of tau leptons produced in e + e − annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value Pτ=−0.164±0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV.A first measurement of the average polarisation P_tau of tau leptons produced in e+e- annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P_tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV
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