13,752 research outputs found

    A preliminary quarantine analysis of a possible Mariner Venus 1972 mission

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    Spacecraft contamination preliminary quarantine analysis for possible 1972 Mariner Venus prob

    Juncture stress fields in multicellular shell structures. Volume IV - Stresses and deformations of fixed-edge segmental spherical shells Final report

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    Equations for thin elastic spherical shells and digital program for analysis of stresses and deformation of fixed edge segmental spherical shells - solution by finite difference techniqu

    Juncture stress fields in multicellular shell structures. Volume III - Stresses and deformations on fixed-edge segmental conical shells Final report

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    Equations for thin elastic conical shells and digital program for analysis of stress and deformation on fixed edge segmental conical shells - solution by finite difference techniqu

    Manual of Criminal Law and Procedure

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    Intended to aid to Alaska law enforcement officers in the performance of their duties in the field, this manual was designed to provide brief, quick access to major points of substantive and procedural criminal law. The manual contained discussion and procedural guidelines for investigatory stops, identification procedures including line-ups, arrest, search and seizure, interrogation, as well as discussion of justification for the use of nondeadly and deadly force whether by peace officers or civilians, culpability, entrapment, trial preparation, and media relations. The section on substantive criminal law deals with a selection of crimes most likely to be encountered by "street" officers as defined with the recently enacted Revised Alaska Criminal Code (effective January 1, 1980), desribing elements of each crime, investigative hints, and differences with previous provisions of the criminal code, where relevant.Alaska Department of Law Grant No. 78-A-014Introduction / Criminal Procedures / Substantive Criminal Law / Justification / Culpability / Entrapment / Trial Preparation / Media Relations / Appendice

    ‘‘There’s so much more to it than what I initially thought’’: Stepping into researchers’ shoes with a class activity in a first year psychology survey course

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    In psychology, it is widely agreed that research methods, although central to the discipline, are particularly challenging to learn and teach, particularly at introductory level. This pilot study explored the potential of embedding a student-conducted research activity in a one-semester undergraduate Introduction to Psychology survey course, with the aims of (a) engaging students with the topic of research methods; (b) developing students’ comprehension and application of research methods concepts; and (c) building students’ ability to link research with theory. The research activity explored shoe ownership, examining gender differences and relationships with age, and linking to theories of gender difference and of consumer identity. The process of carrying out the research and reflecting on it created a contextualized, active learning environment in which students themselves raised many issues that research methods lectures seek to cover. Students also wrote richer assignments than standard first year mid-term essay

    Investigation of juncture stress fields in multicellular shell structures

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    Discontinuity stress fields in thin elastic multicellular shell structures subject to inertial, pressure, and thermal loadin

    Determination of ocean transports and velocities by electromagnetic effects

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    The electric potentials in and about an ocean current are shown to be related in a simple fashion to the total fluid transport. In many waters, surface measurements alone permit the determination of this total transport. It is also established that the local vertical potential gradient is a measure of the local velocity. Several techniques of measurement, including the Geomagnetic electrokinetograph method, and the errors which may be involved in each, are discussed

    Decoherence induced by Smith-Purcell radiation

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    The interaction between charged particles and the vacuum fluctuations of the electromagnetic field induces decoherence, and therefore affects the contrast of fringes in an interference experiment. In this article we show that if a double slit experiment is performed near a conducting grating, the fringe visibility is reduced. We find that the reduction of contrast is proportional to the number of grooves in the conducting surface, and that for realistic values of the parameters it could be large enough to be observed. The effect can be understood in terms of the Smith-Purcell radiation produced by the surface currents induced in the conductor.Comment: 10 pages, 3 figures. Improved discussion on experimental perspectives. References added. Version to appear in Phys. Rev.

    IC 751: a new changing-look AGN discovered by NuSTAR

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    We present the results of five NuSTAR observations of the type 2 active galactic nucleus (AGN) in IC 751, three of which were performed simultaneously with XMM-Newton or Swift/XRT. We find that the nuclear X-ray source underwent a clear transition from a Compton-thick (N H≃2×1024 cm−2N_{\rm\,H}\simeq 2\times 10^{24}\rm\,cm^{-2}) to a Compton-thin (N H≃4×1023 cm−2N_{\rm\,H}\simeq 4\times 10^{23}\rm\,cm^{-2}) state on timescales of ≲3\lesssim 3 months, which makes IC 751 the first changing-look AGN discovered by NuSTAR. Changes of the line-of-sight column density at a ∼2σ\sim2\sigma level are also found on a time-scale of ∼48\sim 48 hours (ΔN H∼1023 cm−2\Delta N_{\rm\,H}\sim 10^{23}\rm\,cm^{-2}). From the lack of spectral variability on timescales of ∼100\sim 100 ks we infer that the varying absorber is located beyond the emission-weighted average radius of the broad-line region, and could therefore be related either to the external part of the broad-line region or a clumpy molecular torus. By adopting a physical torus X-ray spectral model, we are able to disentangle the column density of the non-varying absorber (N H∼3.8×1023 cm−2N_{\rm\,H}\sim 3.8\times 10^{23}\rm\,cm^{-2}) from that of the varying clouds [N H∼(1−150)×1022 cm−2N_{\rm\,H}\sim(1-150)\times10^{22}\rm\,cm^{-2}], and to constrain that of the material responsible for the reprocessed X-ray radiation (N H∼6×1024 cm−2N_{\rm\,H} \sim 6 \times 10^{24}\rm\,cm^{-2}). We find evidence of significant intrinsic X-ray variability, with the flux varying by a factor of five on timescales of a few months in the 2-10 and 10-50 keV band.Comment: Accepted for publication in ApJ, 11 pages, 6 figure

    Superlong GRBs

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    We searched for anomalously long GRBs (GRBs) in the archival records of the Burst and Transient Sources Experiment (BATSE). Ten obvious superlong (>500 s) GRBs with almost continuous emission episodes were found. Nine of these events are known from the BATSE catalog, but five have no duration estimates; we found one burst for the first time. We also detected events with emission episodes separated by a long period of silence (up to 1000 s) with a total duration of 1000--2000 s. In the latter case, we cannot reach an unequivocal conclusion about a common origin of the episodes due to the BATSE poor angular resolution. However, for most of these pairs, the probability of a coincidence of independent GRBs is much lower than unity, and the probability that all of these are coincidences is 10E-8. All of the events have a hardness ratio (the ratio of the count rates in different energy channels) typical of GRBs, and their unique duration is unlikely to be related to their high redshifts. Superlong bursts do not differ in their properties from typical long (>2 s) GRBs. We estimated the fraction of superlong GRBs (>500 s) among the long GRBs in the BATSE sample with fluxes up to 0.1 ph cm^{-2} s^{-1} to be between 0.3 and 0.5%, which is higher than the estimate based on the BATSE catalog.Comment: 11 pages, 4 figures, 3 tables, translation is made by Astronomy Letter
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