1,827 research outputs found

    Unresolved Unidentified Source Contribution to the Gamma-ray Background

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    The large majority of EGRET point sources remain without an identified low-energy counterpart, and a large fraction of these sources are most likely extragalactic. Whatever the nature of the extragalactic EGRET unidentified sources, faint unresolved objects of the same class must have a contribution to the diffuse extragalactic gamma-ray background (EGRB). Understanding this component of the EGRB, along with other guaranteed contributions from known sources, is essential if we are to use this emission to constrain exotic high-energy physics. Here, we follow an empirical approach to estimate whether a potential contribution of unidentified sources to the EGRB is likely to be important, and we find that it is. Additionally, we show how upcoming GLAST observations of EGRET unidentified sources, as well as of their fainter counterparts, can be combined with GLAST observations of the Galactic and extragalactic diffuse backgrounds to shed light on the nature of the EGRET unidentified sources even without any positional association of such sources with low-energy counterparts.Comment: 11 pages, 5 figures, submitted to Ap

    The detection of geothermal areas from Skylab thermal data

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    Skylab-4 X-5 thermal data of the geysers area was analyzed to determine the feasibility of using midday Skylab images to detect geothermal areas. The hottest ground areas indicated on the Skylab image corresponded to south-facing barren or sparsely vegetated slopes. A geothermal area approximately 15 by 30 m coincided with one of the hottest areas indicated by Skylab. This area could not be unambiguously distinguished from the other areas which are believed to be hotter than their surroundings as a result of their topography, and micrometeorological conditions. A simple modification of a previous thermal model was performed and the predicted temperatures for the hottest slopes using representative values was in general agreement with the observed data. It is concluded that data from a single midday Skylab pass cannot be used to locate geothermal areas

    Direct Causation: A New Approach to an Old Question

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    Causative constructions come in lexical and periphrastic variants, exemplified in English by Sam killed Lee and Sam caused Lee to die. While use of the former, the lexical causative, entails the truth of the latter, an entailment in the other direction does not hold. The source of this asymmetry is commonly ascribed to the lexical causative having an additional prerequisite of “direct causation , such that the causative relation holds between a contiguous cause and effect (Fodor 1970, Katz 1970). However, this explanation encounters both empirical and theoretical problems (Nelleman & van der Koot 2012). To explain the source of the directness inferences (as well as other longstanding puzzles), we propose a formal analysis based on the framework of Structural Equation Models (SEMs) (Pearl 2000) which provides the necessary background for licensing causal inferences. Specifically, we provide a formalization of a \u27sufficient set of conditions\u27 within a model and demonstrate its role in the selectional parameters of causative descriptions. We argue that “causal sufficiency” is not a property of singular conditions, but rather sets of conditions, which are individually necessary but only sufficient when taken together (a view originally motivated in the philosophical literature by Mackie 1965). We further introduce the notion of a “completion event” of a sufficient set, which is critical to explain the particular inferential profile of lexical causatives

    Practical Student Self-affirmation

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    This research paper focuses on student peer interactional relationships in a tertiary level classroom setting in Japan. The research is based on the use of one piece of technology, Microsoft PowerPoint, to illustrate student peer interactional relationships during presentation tasks throughout the 2015 Spring Semester. The application of the particular software used in this research is of little importance, in that any piece of software could be used to investigate student interaction. The important findings of this research indicate that students can be made aware of their self-affirmation through an application of sociolinguistics and an introduction of critical pedagogy that encompasses a significant reduction in the influence of the traditional ‘teacher’ role to the benefit of student empowerment. The role of the student changes from being the passive object to that of a more active Subject role, as that of the ‘teacher,’ or better termed ‘facilitator,’ dispenses their traditional paternalistic, authoritative Subject position, in favor of being one that helps to bring about ‘
an outcome (as learning, productivity, or communication) by providing indirect or unobtrusive assistance, guidance, or supervision,’ on the part of the ‘facilitator,’ as it is defined in the Miriam-Webster dictionary (2015). For students to adopt a more active role requires a change in study habits, which requires more effort. However, this adheres perfectly to the Kyoai College motto; ‘You can develop your ability though it might be hard’ (Kyoai, 2015)

    Central European foreign exchange markets: a cross-spectral analysis of the 2007 financial crisis

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    This paper investigates co-movements between currency markets of Czech Republic, Poland, Hungary, Slovakia and the Euro in the year following the drying up of money markets in August 2007. The paper shows that assessing the degree of foreign currency co-movement by correlation can lead to concluding, erroneously, that financial contagion has not occurred. Using cross-spectral methods, the paper shows that defining contagion as changes in the structure of co-movements of asset prices encompasses more of the complex nature of exchange rate dynamics. What is shown is that, following August 2007, there is increased in the intensity of co-movements, but non-linearly. Focusing on the activities of a mix of banks and currency managers, it is suggested that changes in the structure of currency interaction present an unfavourable view of the contagion experienced by at least three of these currencies

    Laboratory Measurement of the Anticoagulant Activity of the Non–Vitamin K Oral Anticoagulants

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    AbstractBackgroundNon–vitamin K oral anticoagulants (NOACs) do not require routine laboratory monitoring. However, laboratory measurement may be desirable in special situations and populations.ObjectivesThis study’s objective was to systematically review and summarize current evidence regarding laboratory measurement of the anticoagulant activity of dabigatran, rivaroxaban, and apixaban.MethodsWe searched PubMed and Web of Science for studies that reported a relationship between drug levels of dabigatran, rivaroxaban, and apixaban and coagulation assay results. Study quality was evaluated using QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2).ResultsWe identified 17 eligible studies for dabigatran, 15 for rivaroxaban, and 4 for apixaban. For dabigatran, a normal thrombin time excludes clinically relevant drug concentrations. The activated partial thromboplastin time (APTT) and prothrombin time (PT) are less sensitive and may be normal at trough drug levels. The dilute thrombin time (R2 = 0.92 to 0.99) and ecarin-based assays (R2 = 0.92 to 1.00) show excellent linearity across on-therapy drug concentrations and may be used for drug quantification. For rivaroxaban and apixaban, anti-Xa activity is linear (R2 = 0.89 to 1.00) over a wide range of drug levels and may be used for drug quantification. Undetectable anti-Xa activity likely excludes clinically relevant drug concentrations. The PT is less sensitive (especially for apixaban); a normal PT may not exclude clinically relevant levels. The APTT demonstrates insufficient sensitivity and linearity for quantification.ConclusionsDabigatran, rivaroxaban, and apixaban exhibit variable effects on coagulation assays. Understanding these effects facilitates interpretation of test results in NOAC-treated patients. More information on the relationship between drug levels and clinical outcomes is needed

    Dark Matter implications of the Fermi-LAT measurement of anisotropies in the diffuse gamma-ray background: status report

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    For the first time, the Fermi-LAT measured the angular power spectrum (APS) of anisotropies in the diffuse gamma-ray background. The data is found to be broadly compatible with a model with contributions from the point sources in the 1-year catalog, the galactic diffuse background, and the extragalactic isotropic emission; however deviations are present at both large and small angular scales. In this study, we complement the model with a contribution from Dark Matter (DM) whose distribution is modeled exploiting the results of the most recent N-body simulations, considering the contribution of extragalactic halos and subhalos (from Millennium-II) and of galactic substructures (from Aquarius). With the use of the Fermi Science Tools, these simulations serve as templates to produce mock gamma-ray count maps for DM gamma-ray emission, both in the case of an annihilating and a decaying DM candidate. The APS will then be computed and compared with the Fermi-LAT results to derive constraints on the DM particle physics properties. The possible systematic due to an imperfect model of the galactic foreground is also studied and taken into account properly. The present paper reports on the status of the project.Comment: Proceeding for the RICAP2011 conferenc

    Development of an Oral Health Survey: Columbus, Ohio

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    This article describes the method used to develop and implement a local oral health survey (Columbus, Ohio) conducted in 1986. With the shift in the national dental disease pattern in the past decade, local oral health information is essential for program planning purposes. A collaborative effort by a city health department, a state health department, a dental school, and a school of public health demonstrated how this group worked harmoniously in a relatively inexpensive venture to determine the oral status of various age groups (grades 1–2, grades 6–7, age 35–44, and age 65 +). This information provided part of the framework for a five-year dental plan at the Columbus Health Department. The survey design will serve as a basis for conducting a similar survey statewide. Modifications of existing oral health survey instruments are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65714/1/j.1752-7325.1988.tb03177.x.pd
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