22,649 research outputs found

    The ethics of access: Towards an equal slice of the pie

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    Ethics is a system of moral principles and of values relating to the Tightness and wrongness of certain actions. When two diametrically opposed obligations conflict with one another, an ethical dilemma occurs. It is settled only by weighing and evaluating the importance of the conflicting obligations. The moral conviction of a democratic society supportive of freedom of information versus the welfare of that public might well be an example of two opposing obligations. Equal access to information by the people versus the provision of relevant and friendly information is another wordset of potentially opposing obligations. The free library for the good of the public versus quality library services is also a contender. It is not so opposing if one considers the statement of Alphonse Trezza (1986) during his tenure with the National Commission on Library and Information Services (NCLIS): "The commitment to public good requires the library to constantly improve quality of services, the effective use of technology, and the efficiency of the operation" (p. 52). Providing access and fulfilling the needs of the majority versus providing access and fulfilling the needs of the minority is yet another opposing set. If one adds the words "equal opportunity" then the impact of this statement upon the library is significant.published or submitted for publicatio

    The study of electrical conduction mechanisms

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    The dielectric response of lunar fines 74241,2 is presented in the audio-frequency range and under lunarlike conditions. Results suggest that volatiles are released during storage and transport of the lunar sample. Apparently, subsequent absorption of volatiles on the sample surface alter its dielectric response. The assumed volatile influence disappear after evacuation. A comparison of the dielectric properties of lunar and terrestrial materials as a function of density, temperature, and frequency indicates that if the lunar simulator analyzed were completely devoid of atmospheric moisture it would present dielectric losses smaller than those of the lunar sample. It is concluded that density prevails over temperature as the controlling factor of dielectric permittivity in the lunar regolith and that dielectric losses vary slowly with depth

    Vented piston seal prevents fluid leakage between two chambers

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    To prevent fluid leakage around piston seals separating two fluids under differential pressure, a venting system has been devised. Two methods may be used for venting seals through internal passages to an external low-pressure area, O-ring or split-ring seals

    Theory and applications of the Vlasov equation

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    Forty articles have been recently published in EPJD as contributions to the topical issue "Theory and applications of the Vlasov equation". The aim of this topical issue was to provide a forum for the presentation of a broad variety of scientific results involving the Vlasov equation. In this editorial, after some introductory notes, a brief account is given of the main points addressed in these papers and of the perspectives they open.Comment: Editoria

    On Krein-like theorems for noncanonical Hamiltonian systems with continuous spectra: application to Vlasov-Poisson

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    The notions of spectral stability and the spectrum for the Vlasov-Poisson system linearized about homogeneous equilibria, f_0(v), are reviewed. Structural stability is reviewed and applied to perturbations of the linearized Vlasov operator through perturbations of f_0. We prove that for each f_0 there is an arbitrarily small delta f_0' in W^{1,1}(R) such that f_0+delta f_0isunstable.When is unstable. When f_0$ is perturbed by an area preserving rearrangement, f_0 will always be stable if the continuous spectrum is only of positive signature, where the signature of the continuous spectrum is defined as in previous work. If there is a signature change, then there is a rearrangement of f_0 that is unstable and arbitrarily close to f_0 with f_0' in W^{1,1}. This result is analogous to Krein's theorem for the continuous spectrum. We prove that if a discrete mode embedded in the continuous spectrum is surrounded by the opposite signature there is an infinitesimal perturbation in C^n norm that makes f_0 unstable. If f_0 is stable we prove that the signature of every discrete mode is the opposite of the continuum surrounding it.Comment: Submitted to the journal Transport Theory and Statistical Physics. 36 pages, 12 figure

    Why are Immigrants' Incarceration Rates so Low? Evidence on Selective Immigration, Deterrence, and Deportation

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    The perception that immigration adversely affects crime rates led to legislation in the 1990s that particularly increased punishment of criminal aliens. In fact, immigrants have much lower institutionalization (incarceration) rates than the native born - on the order of one-fifth the rate of natives. More recently arrived immigrants have the lowest relative incarceration rates, and this difference increased from 1980 to 2000. We examine whether the improvement in immigrants' relative incarceration rates over the last three decades is linked to increased deportation, immigrant self-selection, or deterrence. Our evidence suggests that deportation does not drive the results. Rather, the process of migration selects individuals who either have lower criminal propensities or are more responsive to deterrent effects than the average native. Immigrants who were already in the country reduced their relative institutionalization probability over the decades; and the newly arrived immigrants in the 1980s and 1990s seem to be particularly unlikely to be involved in criminal activity, consistent with increasingly positive selection along this dimension.

    The Role of Deportation in the Incarceration of Immigrants

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    Using data on all new admissions to California state prisons in 1986, 1990, and 1996, we find that the foreign born have a very different offense mix from native-born inmates, with foreigners much more likely to be serving time for drug offenses. We document and discuss many of the substantial changes in the enforcement environment over this period, including the war on drugs, changes in public law expanding the classes eligible for deportation, and increases in the level of resources appropriated for enforcement activities targeting deportable aliens. These developments have resulted in much greater attention by the Immigration and Naturalization Service to the incarceration of the foreign born. By 1996, the definition of deportable' was such that it covered essentially all noncitizens in the California prison system. Throughout the period, those foreign-born inmates designated by the California Department of Corrections to be released to INS custody serve substantially (6-12 percent) longer terms (conditional upon sentence length) than natives or other similar' foreigners. These longer terms of incarceration impose substantial costs on the state.
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