1,466 research outputs found

    School Desegregation and Federalism: The Court inside the Schoolhouse Door

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    Alexander Hamilton characterized the federal judiciary as having “no influence over either the sword or the purse; no direction either of the strength or wealth of society.” In the years since the landmark decision in Brown v. Board of Education, however, federal courts have taken an increasingly active role in controlling the use of resources in school districts where de jure segregation has been found to exist. In examining facts which are more legislative than adjudicative in nature, the courts have often shaped relief which intervenes in the functions of an elected body of officials, in some cases involving the court or its appointed special master in the day to day operation of the school. This judicial activism has not been limited to schools. Federal court orders have controlled the operations of prisons, police departments, and state mental health systems. These decrees can be incredibly detailed; the order enforcing the judgment in Wyatt v. Stickney even specifies the temperature of the hot water supply in Alabama\u27s mental health facilities. The propriety of such relief, and particularly the degree to which federal equitable relief may intrude into what have traditionally been locally controlled activities, has recently been called into question. By combining the traditional limitations of equity jurisprudence with notions of federalism, the Supreme Court has established a delimiting doctrine for the lower federal courts when they exercise equity jurisdiction in civil rights cases. This comment will examine the growth of equitable relief in school desegregation cases and the impact which this limiting doctrine has had. The propriety of using the federal/state relationship as a guide for relief where a violation of the Constitution has been found to exist will also be analyzed.

    Relative Flux Calibration of Keck HIRES Echelle Spectra

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    We describe a new method to calibrate the relative flux levels in spectra from the HIRES echelle spectrograph on the Keck-I telescope. Standard data reduction techniques that transfer the instrument response between HIRES integrations leave errors in the flux of 5 - 10%, because the effective response varies. The flux errors are most severe near the ends of each spectral order, where there can be discontinuous jumps. The source of these errors is uncertain, but may include changes in the vignetting connected to the optical alignment. Our new flux calibration method uses a calibrated reference spectrum of each target to calibrate individual HIRES integrations. We determine the instrument response independently for each integration, and hence we avoid the need to transfer the instrument response between HIRES integrations. The procedure can be applied to any HIRES spectrum, or any other spectrum. While the accuracy of the method depends upon many factors, we have been able to flux calibrate a HIRES spectrum to 1% over scales of 200 A that include order joins. We illustrate the method with spectra of Q1243+3047 towards which we have measured the deuterium to hydrogen abundance ratio.Comment: 24 pages, 17 figures, submitted to PAS

    Neutrinos and Primordial Nucleosynthesis

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    The importance of the Big Bang Nucleosynthesis (BBN) as a unique tool for studying neutrino properties is discussed, and the recent steps towards a self-consistent and robust handling of the weak reaction decoupling from the thermal bath as well as of the neutrino reheating following the e+e- annihilation are summarized. We also emphasize the important role of the Cosmic Microwave Background (CMB) anisotropy in providing an accurate and independent determination of the baryon density parameter omegab. The BBN is presently a powerful parameter-free theory that can test the standard scenario of the neutrino decoupling in the early Universe. Moreover it can constrain new physics in the neutrino sector. The perspectives for improvements in the next years are outlined.Comment: Talk given by G. Mangano at NOW2004, Conca Specchiulla, Otranto Italy, september 2004. To appear in the Proceedings of the Worksho

    Spin and orbital moments of ultra-thin Fe films on various semiconductor surfaces

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    The magnetic moments of ultrathin Fe films on three different III-V semiconductor substrates, namely GaAs, InAs and In0.2Ga0.8As have been measured with X-ray magnetic circular dichroism at room temperature to assess their relative merits as combinations suitable for next-generation spintronic devices. The results revealed rather similar spin moments and orbital moments for the three systems, suggesting the relationship between film and semiconductor lattice parameters to be less critical to magnetic moments than magnetic anisotropy

    McKay matrices for finite-dimensional Hopf algebras

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    For a finite-dimensional Hopf algebra AA, the McKay matrix MVM_V of an AA-module VV encodes the relations for tensoring the simple AA-modules with VV. We prove results about the eigenvalues and the right and left (generalized) eigenvectors of MVM_V by relating them to characters. We show how the projective McKay matrix QVQ_V obtained by tensoring the projective indecomposable modules of AA with VV is related to the McKay matrix of the dual module of VV. We illustrate these results for the Drinfeld double DnD_n of the Taft algebra by deriving expressions for the eigenvalues and eigenvectors of MVM_V and QVQ_V in terms of several kinds of Chebyshev polynomials. For the matrix NVN_V that encodes the fusion rules for tensoring VV with a basis of projective indecomposable DnD_n-modules for the image of the Cartan map, we show that the eigenvalues and eigenvectors also have such Chebyshev expressions

    Non-Gaussian Features of Transmitted Flux of QSO's Lyα\alpha Absorption: Intermittent Exponent

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    We calculate the structure function and intermittent exponent of the 1.) Keck data, which consists of 29 high resolution, high signal to noise ratio (S/N) QSO Lyα\alpha absorption spectra, and 2.)the Lyα\alpha forest simulation samples produced via the pseudo hydro scheme for the low density cold dark matter (LCDM) model and warm dark matter (WDM) model with particle mass mW=300,600,800m_W=300, 600, 800 and 1000 eV. These two measures detect not only non-gaussianities, but also the type of non-gaussianty in the the field. We find that, 1.) the structure functions of the simulation samples are significantly larger than that of Keck data on scales less than about 100 h1^{-1} kpc, 2.) the intermittent exponent of the simulation samples is more negative than that of Keck data on all redshifts considered, 3.) the order-dependence of the structure functions of simulation samples are closer to the intermittency of hierarchical clustering on all scales, while the Keck data are closer to a lognormal field on small scales. These differences are independent of noise and show that the intermittent evolution modeled by the pseudo-hydro simulation is substantially different from observations, even though they are in good agreement in terms of second and lower order statistics. (Abridged)Comment: 17 pages, 13 figures. Accepted by Ap

    Constraints on massive gravity theory from big bang nucleosynthesis

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    The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The cosmological consequences of the model are also discussed in the framework of the PAMELA experiment.Comment: 5 page

    Calculations of the Local Density of States for some Simple Systems

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    A recently proposed convolution technique for the calculation of local density of states is described more thouroughly and new results of its application are presented. For separable systems the exposed method allows to construct the ldos for a higher dimensionality out of lower dimensional parts. Some practical and theoretical aspects of this approach are also discussed.Comment: 5 pages, 3 figure

    Evidence for density dependent population regulation in southern elephant seals in the southern Indian Ocean

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    The means by which populations are regulated form a central theme in conservation biology, and much debate has revolved around density dependence as a mechanism driving population change. Marion Island (46o54'S, 37o45'E) is host to a relatively small breeding population of southern elephant seals, which like its counterparts in the southern Indian and southern Pacific Oceans, have declined precipitously over the past few decades. An intensive mark-recapture study, which commenced in 1983, has yielded a long time-series of resight data on this population. We used the program MARK to estimate adult female survival in this population from resight data collected over the period 1986-1999. Including concurrent population counts as covariates significantly improved our mark-recapture models and suggests density dependent population regulation to be operational in the population. Although predation may have been involved, it is far more likely that density dependent regulation has been based on a limited food supply. A significant increase in adult female survival was evident which is likely to have given rise to recent changes in population growth
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