4,652 research outputs found
Dipole-interacting Fermionic Dark Matter in positron, antiproton, and gamma-ray channels
Cosmic ray signals from dipole-interacting dark matter annihilation are
considered in the positron, antiproton and photon channels. The predicted
signals in the positron channel could nicely account for the excess of positron
fraction from Fermi LAT, PAMELA, HEAT and AMS-01 experiments for the dark
matter mass larger than 100 GeV with a boost (enhancement) factor of 30-80. No
excess of antiproton over proton ratio at the experiments also gives a severe
restriction for this scenario. With the boost factors, the predicted signals
from Galactic halo and signals as mono-energetic gamma-ray lines (monochromatic
photons) for the region close to the Galactic center are investigated. The
gamma-ray excess of recent tentative analyses based on Fermi LAT data and the
potential probe of the monochromatic lines at a planned experiment, AMS-02, are
also considered.Comment: Version to be published in PRD(2013), Title changed, text modifie
Learning a Static Analyzer from Data
To be practically useful, modern static analyzers must precisely model the
effect of both, statements in the programming language as well as frameworks
used by the program under analysis. While important, manually addressing these
challenges is difficult for at least two reasons: (i) the effects on the
overall analysis can be non-trivial, and (ii) as the size and complexity of
modern libraries increase, so is the number of cases the analysis must handle.
In this paper we present a new, automated approach for creating static
analyzers: instead of manually providing the various inference rules of the
analyzer, the key idea is to learn these rules from a dataset of programs. Our
method consists of two ingredients: (i) a synthesis algorithm capable of
learning a candidate analyzer from a given dataset, and (ii) a counter-example
guided learning procedure which generates new programs beyond those in the
initial dataset, critical for discovering corner cases and ensuring the learned
analysis generalizes to unseen programs.
We implemented and instantiated our approach to the task of learning
JavaScript static analysis rules for a subset of points-to analysis and for
allocation sites analysis. These are challenging yet important problems that
have received significant research attention. We show that our approach is
effective: our system automatically discovered practical and useful inference
rules for many cases that are tricky to manually identify and are missed by
state-of-the-art, manually tuned analyzers
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Influence of error terms in Bayesian calibration of energy system models
Calibration represents a crucial step in the modelling process to obtain accurate simulation results and quantify uncertainties. We scrutinise the statistical Kennedy & OâHagan framework, which quantifies different sources of uncertainty in the calibration process, including both model inputs and errors in the model. In specific, we evaluate the influence of error terms on the posterior predictions of calibrated model inputs. We do so by using a simulation model of a heat pump in cooling mode. While posterior values of many parameters concur with the expectations, some parameters appear not to be inferable. This is particularly true for parameters associated with model discrepancy, for which prior knowledge is typically scarce. We reveal the importance of assessing the identifiability of parameters by exploring the dependency of posteriors on the assigned prior knowledge. Analyses with random datasets show that results are overall consistent, which confirms the applicability and reliability of the framework
Overweight, obesity, and colorectal cancer screening: Disparity between men and women
BACKGROUND: To estimate the association between body-mass index (BMI: kg/m(2)) and colorectal cancer (CRC) screening among US adults aged â„ 50 years. METHODS: Population-based data from the 2001 Behavioral Risk Factor Surveillance Survey. Adults (N = 84,284) aged â„ 50 years were classified by BMI as normal weight (18.5â<25), overweight (25â<30), obesity class I (30â<35), obesity class II (35â<40), and obesity class III (â„ 40). Interval since most recent screening fecal occult blood test (FOBT): (0 = >1 year since last screening vs. 1 = screened within the past year), and screening sigmoidoscopy (SIG): (0 = > 5 years since last screening vs. 1 = within the past 5 years) were the outcomes. RESULTS: Results differed between men and women. After adjusting for age, health insurance, race, and smoking, we found that, compared to normal weight men, men in the overweight (odds ratio [OR] 1.25, 95% CI = 1.05â1.51) and obesity class I (OR = 1.21, 95% CI = 1.03â1.75) categories were more likely to have obtained a screening SIG within the previous 5 years, while women in the obesity class I (OR = 0.86, 95%CI = 0.78â0.94) and II (OR = 0.88, 95%CI = 0.79â0.99) categories were less likely to have obtained a screening SIG compared to normal weight women. BMI was not associated with FOBT. CONCLUSION: Weight may be a correlate of CRC screening behavior but in a different way between men and women
Sommerfeld enhancement from Goldstone pseudo-scalar exchange
We point out that the exchange of a Goldstone pseudo-scalar can provide an
enhancement in the dark matter annihilation rate capable of explaining the
excess flux seen in high energy cosmic ray data. The mechanism of enhancement
involves the coupling of s and d waves through the tensor force that is very
strong and, in fact, singular at short distances. The results indicate that
large enhancements require some amount of fine tuning. We also discuss the
enhancement due to other singular attractive potentials, such as WIMP models
with a permanent electric dipole.Comment: 14 pages, 4 figures, v2 includes contact informatio
Satisfaction with food policies for consumer
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žíž : Selected paper prepared for presentation at the Agricultural & Applied Economics Associationâs 2016 AAEA Annual Meeting, Boston, Massachusetts, July 31-August 2, 201
Raman-scattered O VI Features in the Symbiotic Nova RR Telescopii
RR Tel is an interacting binary system in which a hot white dwarf (WD) accretes matter from a Mira-type variable star via gravitational capture of its stellar wind. This symbiotic nova shows intense Raman-scattered O VI 1032 and 1038 features at 6825 ËA and 7082 ËA. We present high-resolution optical spectra of RR Tel taken in 2016 and 2017 with the Magellan Inamori Kyocera Echelle (MIKE) spectrograph at Magellan-Clay telescope, Chile. We aim to study the stellar wind accretion in RR Tel from the profile analysis of Raman O VI features. With an asymmetric O VI disk model, we derive a representative Keplerian speed of > 35 km sâ1 , and the corresponding scale < 0.8 au. The best-fit for the Raman profiles is obtained with a mass loss rate of the Mira MË âŒ 2 Ă 10â6 M yrâ1 and a wind terminal velocity vâ ⌠20 km sâ1 . We compare the MIKE data with an archival spectrum taken in 2003 with the Fibre-fed Extended Range Optical Spectrograph (FEROS) at the MPG/ESO 2.2 m telescope. It allows us to highlight the profile variation of the Raman O VI features, indicative of a change in the density distribution of the O VI disk in the last two decades. We also report the detection of O VI recombination lines at 3811 ËA and 3834 ËA, which are blended with other emission lines. Our profile decomposition suggests that the recombination of O VII takes place nearer to the WD than the O VI 1032 and 1038 emission region.Fil: Heo, J. E.. Observatorio Gemini; Chile. Universidad de La Serena; Chile. Sejong University; Corea del SurFil: Lee, H. W.. Universidad de Sejong; Corea del SurFil: Angeloni, R.. Universidad de La Serena; ChileFil: Palma, Tali. Universidad Nacional de CĂłrdoba. Observatorio AstronĂłmico de CĂłrdoba. Departamento de AstrofĂsica Estelar; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba; ArgentinaFil: Di Mille, F.. Observatorio Las Campanas; Chil
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