1,215 research outputs found

    Are affirmative action hires less qualified? Evidence from employer-employee data on new hires

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    In this paper we use micro-level data on employers and employees to investigate whether Affirmative Action procedures lead firms to hire minority or female employees who are less qualified than workers who might otherwise be hired. Our measures of qualifications include the educational attainment of the workers hired (both absolute and relative to job requirements), skill requirements of the job into which they are hired, and a variety of outcome measures that are presumably related to worker performance on the job. The analysis is based on a representative sample of over 3,200 employers in four major metropolitan areas in the United States. Our results show some evidence of lower educational qualifications among blacks and Hispanics hired under Affirmative Action, but not among white women. Further, our results show little evidence of substantially weaker job performance among most groups of minority and female Affirmative Action hires.

    What Does Affirmative Action Do?

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    We use data from a survey of employers to investigate how Affirmative Action in recruiting and hiring influences hiring practices, personnel policies, and ultimately employment out- comes. Our results show that Affirmative Action increases the number of recruitment and screening practices used by employers, raises their willingness to hire stigmatized applicants, increases the number of minority and female applicants as well as employees, and increases employers’ tendencies to provide training and to formally evaluate employees. When Affirmative Action is used in recruiting, it does not lead to lower credentials or performance of women and minorities hired. When it is also used in hiring, it yields female and minority employees whose credentials are somewhat weaker, though performance generally is not. Overall, then, the more intensive search, evaluation, and training that accompany Affirmative Action appear to offset any tendencies of the policy to lead to hiring of less-qualified or less-productive women and minorities.

    Optical realization of optimal unambiguous discrimination for pure and mixed quantum states

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    Quantum mechanics forbids deterministic discrimination among non-orthogonal states. Nonetheless, the capability to distinguish nonorthogonal states unambiguously is an important primitive in quantum information processing. In this work, we experimentally implement generalized measurements in an optical system and demonstrate the first optimal unambiguous discrimination between three nonorthogonal states, with a success rate of 55%, to be compared with the 25% maximum achievable using projective measurements. Furthermore we present the first realization of unambiguous discrimination between a pure state and a nonorthogonal mixed state.Comment: Some minor revision

    Minimum-error discrimination between three mirror-symmetric states

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    We present the optimal measurement strategy for distinguishing between three quantum states exhibiting a mirror symmetry. The three states live in a two-dimensional Hilbert space, and are thus overcomplete. By mirror symmetry we understand that the transformation {|+> -> |+>, |-> -> -|->} leaves the set of states invariant. The obtained measurement strategy minimizes the error probability. An experimental realization for polarized photons, realizable with current technology, is suggested.Comment: 4 pages, 2 figure

    Realizations of Causal Manifolds by Quantum Fields

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    Quantum mechanical operators and quantum fields are interpreted as realizations of timespace manifolds. Such causal manifolds are parametrized by the classes of the positive unitary operations in all complex operations, i.e. by the homogenous spaces \D(n)=\GL(\C^n_\R)/\U(n) with n=1n=1 for mechanics and n=2n=2 for relativistic fields. The rank nn gives the number of both the discrete and continuous invariants used in the harmonic analysis, i.e. two characteristic masses in the relativistic case. 'Canonical' field theories with the familiar divergencies are inappropriate realizations of the real 4-dimensional causal manifold \D(2). Faithful timespace realizations do not lead to divergencies. In general they are reducible, but nondecomposable - in addition to representations with eigenvectors (states, particle) they incorporate principal vectors without a particle (eigenvector) basis as exemplified by the Coulomb field.Comment: 36 pages, latex, macros include

    Maximum-confidence discrimination among symmetric qudit states

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    We study the maximum-confidence (MC) measurement strategy for discriminating among nonorthogonal symmetric qudit states. Restricting to linearly dependent and equally likely pure states, we find the optimal positive operator valued measure (POVM) that maximizes our confidence in identifying each state in the set and minimizes the probability of obtaining inconclusive results. The physical realization of this POVM is completely determined and it is shown that after an inconclusive outcome, the input states may be mapped into a new set of equiprobable symmetric states, restricted, however, to a subspace of the original qudit Hilbert space. By applying the MC measurement again onto this new set, we can still gain some information about the input states, although with less confidence than before. This leads us to introduce the concept of "sequential maximum-confidence" (SMC) measurements, where the optimized MC strategy is iterated in as many stages as allowed by the input set, until no further information can be extracted from an inconclusive result. Within each stage of this measurement our confidence in identifying the input states is the highest possible, although it decreases from one stage to the next. In addition, the more stages we accomplish within the maximum allowed, the higher will be the probability of correct identification. We will discuss an explicit example of the optimal SMC measurement applied in the discrimination among four symmetric qutrit states and propose an optical network to implement it.Comment: 14 pages, 4 figures. Published versio

    Shared Risk Factors for Mood-, Eating-, and Weight-Related Health Outcomes

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    Objective: Given the overlap among depressive symptoms, disordered eating, and overweight, identifying shared risk factors for these conditions may inform public health interventions. This study aimed to examine cross-sectional and prospective relationships among these 3 conditions, and identify potential shared eating-related and psychosocial variable risk factors (i.e., body dissatisfaction, dieting, teasing experiences). Method: A population-based sample (n = 1,902) self-reported depressive symptoms, disordered eating (binge eating, extreme weight control behaviors), weight status, and several putative risk factors (body satisfaction, dieting frequency, weight-related teasing) at 5-year intervals spanning early/middle adolescence, middle adolescence/early young adulthood, and early/middle young adulthood. Results: There was moderate overlap among depressive symptoms, disordered eating, and overweight at each time point, and moderate stability in each condition over time. Body dissatisfaction and dieting were the most potent shared risk factors for later depressive symptoms, disordered eating, and overweight among males and females (ps \u3c .05). Conclusions: Depressive symptoms, disordered eating, and overweight share several risk factors, including dieting and body dissatisfaction, which may be effective targets for interventions aiming to simultaneously prevent these 3 conditions

    Neumark Operators and Sharp Reconstructions, the finite dimensional case

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    A commutative POV measure FF with real spectrum is characterized by the existence of a PV measure EE (the sharp reconstruction of FF) with real spectrum such that FF can be interpreted as a randomization of EE. This paper focuses on the relationships between this characterization of commutative POV measures and Neumark's extension theorem. In particular, we show that in the finite dimensional case there exists a relation between the Neumark operator corresponding to the extension of FF and the sharp reconstruction of FF. The relevance of this result to the theory of non-ideal quantum measurement and to the definition of unsharpness is analyzed.Comment: 37 page

    Associations between body mass index, weight control concerns and behaviors, and eating disorder symptoms among non-clinical Chinese adolescents

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    <p>Abstract</p> <p>Background</p> <p>Previous research with adolescents has shown associations of body weight, weight control concerns and behaviors with eating disorder symptoms, but it is unclear whether these associations are direct or whether a mediating effect exists. This study was conducted to investigate the prevalence of overweight and obesity, weight control concerns and behaviors, and eating disorder symptoms and to examine the mediating function of weight control concerns and behaviors on the relationship between body mass index (BMI) and eating disorder symptoms among non-clinical adolescents in China.</p> <p>Methods</p> <p>A cross-sectional survey among 2019 adolescent girls and 1525 adolescent boys in the 7th, 8th, 10th and 11th grades from seven cities in China was conducted. Information on weight control concerns and behaviors, and eating disorder symptoms (Eating Disorder Inventory-3) were collected from the adolescents using a self-administrated questionnaire.</p> <p>Results</p> <p>Weight control concerns and behaviors, and eating disorder symptoms were prevalent among the study population. A high proportion of adolescents scored at or above the threshold on the eating disorder inventory (EDI) subscale such as bulimia, interoceptive deficits, perfectionism, and maturity fears, which indicated eating disorder symptoms. High BMI was significantly associated with high score of drive for thinness, body dissatisfaction, bulimia, low self-esteem, interceptive deficits and maturity fears, so do perceived body weight status. Almost all weight control concerns and behaviors we investigated were significantly associated with high EDI subscale scores. When weight control concerns were added to the model, as shown in the model, the association between BMI and tendency of drive to thinness and bulimia was attenuated but still kept significant. The association between BMI and body dissatisfaction were no further significant. The association of BMI and drive for thinness, body dissatisfaction and bulimia was considerably weaker than when weight control behaviors were not included.</p> <p>Conclusions</p> <p>Weight control concerns and behaviors may be mediators of the association between BMI and eating disorder symptoms. Interpretation of these weight control problems is crucial to develop culturally appropriate educational and intervention programs for adolescents.</p
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