19,010 research outputs found

    Inequalities for electron-field correlation functions

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    I show that there exists a class of inequalities between correlation functions of different orders of a chaotic electron field. These inequalities lead to the antibunching effect and are a consequence of the fact that electrons are fermions -- indistinguishable particles with antisymmetric states. The derivation of the inequalities is based on the known form of the correlation functions for the chaotic state and on the properties of matrices and determinants.Comment: 8 pages Latex2e, 2 eps figure

    How Does the Government (Want to) Fund Science? Politics, Lobbying and Academic Earmarks

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    This paper examines academic earmarks and their role in the funding of university research. It provides a summary and review of the evidence on the supply of earmarks by legislators. It then discusses the role of university lobbying for earmarks on the demand side. Finally, the paper examines the impact of earmarks on research quantity and quality.

    Academic Earmarks and the Returns to Lobbying

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    Despite a large literature on lobbying and information transmission by interest groups, no prior study has measured returns to lobbying. In this paper, we statistically estimate the returns to lobbying by universities for educational earmarks (which now represent 10 percent of federal funding of university research). The returns to lobbying approximate zero for universities not represented by a member of the Senate Appropriations Committee (SAC) or House Appropriations Committee (HAC). However, the average lobbying university with representation on the SAC receives an average return to one dollar of lobbying of 1111-17; lobbying universities with representation on the HAC obtain 2020-36 for each dollar spent. Moreover, we cannot reject the hypothesis that lobbying universities with SAC or HAC representation set the marginal benefit of lobbying equal to its marginal cost, although the large majority of universities with representation on the HAC and SAC do not lobby, and thus do not take advantage of their representation in Congress. On average, 45 percent of universities are predicted to choose the optimal level of lobbying. In addition to addressing questions about the federal funding of university research, we also discuss the impact of our results for the structure of government.

    Correlation Functions and Spin

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    The k-electron correlation function of a free chaotic electron beam is derived with the spin degree of freedom taken into account. It is shown that it can be expressed with the help of correlation functions for a polarized electron beam of all orders up to k and the degree of spin polarization. The form of the correlation function suggests that if the electron beam is not highly polarized, observing multi-particle correlations should be difficult. The result can be applied also to chaotic photon beams, the degree of spin polarization being replaced by the degree of polarization.Comment: 6 pages, 1 eps figure, accepted to Phys. Rev.

    The Effects of Negative Legacies on the Adjustment of Parentally Bereaved Children and Adolescents

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    This is a report of a qualitative analysis of a sample of bereaved families in which one parent died and in which children scored in the clinical range on the Child Behavior Check List. The purpose of this analysis was to learn more about the lives of these children. They were considered to be at risk of developing emotional and behavioral problems associated with the death. We discovered that many of these “high risk” children had a continuing bond with the deceased that was primarily negative and troubling for them in contrast to a comparison group of children not at risk from the same study. Five types of legacies, not mutually exclusive, were identified: health related, role related, personal qualities, legacy of blame, and an emotional legacy. Coping behavior on the part of the surviving parent seemed to make a difference in whether or not a legacy was experienced as negative

    Study of explosions in the NASA-MSC Vibration and Acoustic Test Facility /VATF/ Final report

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    Damage potential of titanium alloy pressure spheres relative to spacecraft vibration testin

    Applicability of 100kWe-class of space reactor power systems to NASA manned space station missions

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    An assessment is made of a manned space station operating with sufficiently high power demands to require a multihundred kilowatt range electrical power system. The nuclear reactor is a competitor for supplying this power level. Load levels were selected at 150kWe and 300kWe. Interactions among the reactor electrical power system, the manned space station, the space transportation system, and the mission were evaluated. The reactor shield and the conversion equipment were assumed to be in different positions with respect to the station; on board, tethered, and on a free flyer platform. Mission analyses showed that the free flyer concept resulted in unacceptable costs and technical problems. The tethered reactor providing power to an electrolyzer for regenerative fuel cells on the space station, results in a minimum weight shield and can be designed to release the reactor power section so that it moves to a high altitude orbit where the decay period is at least 300 years. Placing the reactor on the station, on a structural boom is an attractive design, but heavier than the long tethered reactor design because of the shield weight for manned activity near the reactor

    Points of Low Height on Elliptic Curves and Surfaces, I: Elliptic surfaces over P^1 with small d

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    For each of n=1,2,3 we find the minimal height h^(P) of a nontorsion point P of an elliptic curve E over C(T) of discriminant degree d=12n (equivalently, of arithmetic genus n), and exhibit all (E,P) attaining this minimum. The minimal h^(P) was known to equal 1/30 for n=1 (Oguiso-Shioda) and 11/420 for n=2 (Nishiyama), but the formulas for the general (E,P) were not known, nor was the fact that these are also the minima for an elliptic curve of discriminant degree 12n over a function field of any genus. For n=3 both the minimal height (23/840) and the explicit curves are new. These (E,P) also have the property that that mP is an integral point (a point of naive height zero) for each m=1,2,...,M, where M=6,8,9 for n=1,2,3; this, too, is maximal in each of the three cases.Comment: 15 pages; some lines in the TeX source are commented out with "%" to meet the 15-page limit for ANTS proceeding

    The Full Range of Predictions for B Physics From Iso-singlet Down Quark Mixing

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    We extend the range of predictions of the isosinglet (or vector) down quark model to the fully allowed physical ranges, and also update this with the effect of new physics constraints. We constrain the present allowed ranges of sin(2*beta) and sin(2*alpha), gamma, x_s, and A_{B_s}. In models allowing mixing to a new isosinglet down quark (as in E_6) flavor changing neutral currents are induced that allow a Z^0 mediated contribution to B-Bbar mixing and which bring in new phases. In (rho, eta), (x_s, sin(gamma)), and (x_s, A_{B_s}) plots for the extra isosinglet down quark model which are herein extended to the full physical range, we find new allowed regions that will require experiments on sin(gamma) and/or x_s to verify or to rule out an extra down quark contribution.Comment: 13 pages in RevTeX, 7 postscript figure

    A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6

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    Using a compilation of 25 studies from the literature, we investigate the evolution of the star-forming galaxy (SFG) Main Sequence (MS) in stellar mass and star formation rate (SFR) out to z6z \sim 6. After converting all observations to a common set of calibrations, we find a remarkable consensus among MS observations (0.1\sim 0.1 dex 1σ\sigma interpublication scatter). By fitting for time evolution of the MS in bins of constant mass, we deconvolve the observed scatter about the MS within each observed redshift bins. After accounting for observed scatter between different SFR indicators, we find the width of the MS distribution is 0.2\sim 0.2 dex and remains constant over cosmic time. Our best fits indicate the slope of the MS is likely time-dependent, with our best fit logSFR(M,t)=(0.84±0.020.026±0.003×t)logM(6.51±0.240.11±0.03×t)\log\textrm{SFR}(M_*,t) = \left(0.84 \pm 0.02 - 0.026 \pm 0.003 \times t\right) \log M_* - \left(6.51 \pm 0.24 - 0.11 \pm 0.03 \times t\right), with tt the age of the Universe in Gyr. We use our fits to create empirical evolutionary tracks in order to constrain MS galaxy star formation histories (SFHs), finding that (1) the most accurate representations of MS SFHs are given by delayed-τ\tau models, (2) the decline in fractional stellar mass growth for a "typical" MS galaxy today is approximately linear for most of its lifetime, and (3) scatter about the MS can be generated by galaxies evolving along identical evolutionary tracks assuming an initial 1σ1\sigma spread in formation times of 1.4\sim 1.4 Gyr.Comment: 59 pages, 10 tables, 12 figures, accepted to ApJS; v2, slight changes to text, added new figure and fit
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