881 research outputs found

    Psychanalyse et lecture (extraits de 5 Readers Reading)

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    Profiles of Dark Matter Velocity Anisotropy in Simulated Clusters

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    We report statistical results for dark matter (DM) velocity anisotropy, \beta, from a sample of some 6000 cluster-size halos (at redshift zero) identified in a \Lambda CDM hydrodynamical adaptive mesh refinement simulation performed with the Enzo code. These include profiles of \beta\ in clusters with different masses, relaxation states, and at several redshifts, modeled both as spherical and triaxial DM configurations. Specifically, although we find a large scatter in the DM velocity anisotropy profiles of different halos (across elliptical shells extending to at least ~1.5rvir1.5 r_{vir}), universal patterns are found when these are averaged over halo mass, redshift, and relaxation stage. These are characterized by a very small velocity anisotropy at the halo center, increasing outward to about 0.27 and leveling off at about 0.2rvir0.2 r_{vir}. Indirect measurements of the DM velocity anisotropy fall on the upper end of the theoretically expected range. Though measured indirectly, the estimations are derived by using two different surrogate measurements - X-ray and galaxy dynamics. Current estimates of the DM velocity anisotropy are based on very small cluster sample. Increasing this sample will allow testing theoretical predictions, including the speculation that the decay of DM particles results in a large velocity boost. We also find, in accord with previous works, that halos are triaxial and likely to be more prolate when unrelaxed, whereas relaxed halos are more likely to be oblate. Our analysis does not indicate that there is significant correlation (found in some previous studies) between the radial density slope, \gamma, and \beta\ at large radii, 0.3rvir<r<rvir0.3 r_{vir} < r < r_{vir}.Comment: 12 pages, 17 figures, accepted to Ap

    Should We Learn Probabilistic Models for Model Checking? A New Approach and An Empirical Study

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    Many automated system analysis techniques (e.g., model checking, model-based testing) rely on first obtaining a model of the system under analysis. System modeling is often done manually, which is often considered as a hindrance to adopt model-based system analysis and development techniques. To overcome this problem, researchers have proposed to automatically "learn" models based on sample system executions and shown that the learned models can be useful sometimes. There are however many questions to be answered. For instance, how much shall we generalize from the observed samples and how fast would learning converge? Or, would the analysis result based on the learned model be more accurate than the estimation we could have obtained by sampling many system executions within the same amount of time? In this work, we investigate existing algorithms for learning probabilistic models for model checking, propose an evolution-based approach for better controlling the degree of generalization and conduct an empirical study in order to answer the questions. One of our findings is that the effectiveness of learning may sometimes be limited.Comment: 15 pages, plus 2 reference pages, accepted by FASE 2017 in ETAP

    The Ursinus Weekly, May 23, 1960

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    Dr. Paisley completes 50 years as Board President • Alumni Day to be held June 4 • Library has comedy of errors display • Sigma Rho Lambda sponsors annual dinner dance on May 20 • Brownback-Anders pre-medical society elects new officers • Phi Psi and Tau Sig hold picnic in college woods • Baccalaureate speaker will be Dr. D. Horton • Officers selected for new UC group • Pete Wise is re-elected as president of the Newman Club • John Innes wins two outstanding chemistry awards • Awards presented at WAA banquet • Robert Linker is elected new president of student PSEA • Senator Scott to speak at June 6th graduation • Senior banquet is tonight at 7 • Men elect soph rulers; Feldstein is head • WSGA passes revised rules drawn up by the senate • Mike Mehrer is selected new Debating Club head • Language clubs select officers for next year • Editorial: Examinations • Letters to the editor • Requisition: 1960 • International events • Reviews: New and blue; New Lantern • Lacrosse team ends undefeated • Diamondmen eke win over Wilkes • Wenhold given top Varsity Club award • Track team ends with 5-5 season • Stroudsburg girls shade softballershttps://digitalcommons.ursinus.edu/weekly/1365/thumbnail.jp

    Sub-mm detection of a high redshift Type 2 QSO

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    We report on the first SCUBA detection of a Type 2 QSO at z=3.660 in the Chandra Deep Field South. This source is X-ray absorbed, shows only narrow emission lines in the optical spectrum and is detected in the sub-mm: it is the ideal candidate in an evolution scheme for AGN (e.g. Fabian (1999); Page et al. (2004)) of an early phase corresponding to the main growth of the host galaxy and formation of the central black hole. The overall photometry (from the radio to the X-ray energy band) of this source is well reproduced by the spectral energy distribution (SED) of NGC 6240, while it is incompatible with the spectrum of a Type 1 QSO (3C273) or a starburst galaxy (Arp 220). Its sub-mm (850 \mu m) to X-ray (2 keV) spectral slope (alpha_SX) is close to the predicted value for a Compton-thick AGN in which only 1% of the nuclear emission emerges through scattering. Using the observed flux at 850 \mu m we have derived a SFR=550--680 Modot/yrandanestimateofthedustmass,M_odot/yr and an estimate of the dust mass, M_dust=4.2 10^8 M_odotComment: 6 Pages, 5 Figures, accepted for publication in MNRA

    Hilbert Lattice Equations

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    There are five known classes of lattice equations that hold in every infinite dimensional Hilbert space underlying quantum systems: generalised orthoarguesian, Mayet's E_A, Godowski, Mayet-Godowski, and Mayet's E equations. We obtain a result which opens a possibility that the first two classes coincide. We devise new algorithms to generate Mayet-Godowski equations that allow us to prove that the fourth class properly includes the third. An open problem related to the last class is answered. Finally, we show some new results on the Godowski lattices characterising the third class of equations.Comment: 24 pages, 3 figure

    Shuttle walk tests in people with COPD who demonstrate exercise-induced oxygen desaturation: An analysis of test repeatability and cardiorespiratory responses

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    © 2017, © The Author(s) 2017. Exercise-induced oxygen desaturation (EID) is prevalent in people with chronic obstructive pulmonary disease (COPD). This article reports a sub-analysis from a randomized controlled trial (RCT) in people with COPD and EID (COPD/EID). The primary aim, in people with COPD/ EID, was to determine the repeatability of the distance and time walked in the incremental shuttle walk test (ISWT) and endurance shuttle walk test (ESWT), respectively. A secondary aim was to determine whether any participant characteristics predicted those who did not demonstrate improvements on a repeat ISWT or ESWT. Participants with nadir oxygen saturation (SpO2) &lt; 90% on the 6-minute walk test were recruited to the RCT. Two ISWTs and two ESWTs were then performed as part of the baseline assessments, and participants were included in this sub-analysis if their nadir SpO2was &lt;90% during the better of two ISWTs. Repeatability of the tests was analysed using Bland–Altman plots and paired t-tests. Participant characteristics of age, lung function, level of nadir SpO2and end-test dyspnoea were used to predict those who were not likely to demonstrate improvements on a repeat test using receiver operating curves. Eighty-seven participants (mean age (standard deviation, SD) 70 (7) years; forced expiratory volume in one second (FEV1) 47 (17)% predicted) were included. The mean differences (coefficient of repeatability) for the ISWTs and ESWTs were 9 m (55 m) and 19 seconds (142 seconds) respectively (p &lt; 0.05). No participant characteristic predicted the absence of improvement on the second ISWT (area under the curve (AUC) ranged from 0.49 to 0.58, all p &gt; 0.2) or the second ESWT (AUC ranged from 0.43 to 0.52, all p &gt; 0.3). Although repeating the tests showed only small improvements in distance (ISWT) and time (ESWT) walked in people with COPD/EID, the variability was large making definite conclusions about test repeatability in these individuals difficult
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