21,189 research outputs found

    Preferences, Information, and Parental Choice Behavior in Public School Choice

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    The incentives and outcomes generated by public school choice depend to a large degree on parents' choice behavior. There is growing empirical evidence that low-income parents place lower weights on academics when choosing schools, but there is little evidence as to why. We use a field experiment in the Charlotte-Mecklenburg Public School district (CMS) to examine the degree to which information costs impact parental choices and their revealed preferences for academic achievement. We provided simplified information sheets on school average test scores or test scores coupled with estimated odds of admission to students in randomly selected schools along with their CMS school choice forms. We find that receiving simplified information leads to a significant increase in the average test score of the school chosen. This increase is equivalent to a doubling in the implicit preference for academic performance in a random utility model of school choice. Receiving information on odds of admission further increases the effect of simplified test score information on preferences for test scores among low-income families, but dampens the effect among higher-income families. Using within-family changes in choice behavior, we provide evidence that the estimated impact of simplified information is more consistent with lowered information costs than with suggestion or saliency.

    Keck Spectroscopy of distant GOODS Spheroidal Galaxies: Downsizing in a Hierarchical Universe

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    We analyze the evolution of the Fundamental Plane for 141 field spheroidal galaxies in the redshift range 0.2<z<1.2, selected morphologically to a magnitude limit F850LP=22.43 in the northern field of the Great Observatories Origin Survey. For massive galaxies we find that the bulk of the star formation was completed prior to z=2. However, for the lower mass galaxies, the luminosity-weighted ages are significantly younger. The differential change in mass-to-light ratio correlates closely with rest-frame color, consistent with recent star formation and associated growth. Our data are consistent with mass rather than environment governing the overall growth, contrary to the expectations of hierarchical assembly. We discuss how feedback, conduction, and galaxy interactions may explain the downsizing trends seen within our large sample.Comment: ApJ Letters, in press. 4 figure

    Quantum Entanglement and Communication Complexity

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    We consider a variation of the multi-party communication complexity scenario where the parties are supplied with an extra resource: particles in an entangled quantum state. We show that, although a prior quantum entanglement cannot be used to simulate a communication channel, it can reduce the communication complexity of functions in some cases. Specifically, we show that, for a particular function among three parties (each of which possesses part of the function's input), a prior quantum entanglement enables them to learn the value of the function with only three bits of communication occurring among the parties, whereas, without quantum entanglement, four bits of communication are necessary. We also show that, for a particular two-party probabilistic communication complexity problem, quantum entanglement results in less communication than is required with only classical random correlations (instead of quantum entanglement). These results are a noteworthy contrast to the well-known fact that quantum entanglement cannot be used to actually simulate communication among remote parties.Comment: 10 pages, latex, no figure

    Temperature induced solubility transitions of various poly(2-oxazoline)s in ethanol-water solvent mixtures

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    The solution behavior of a series of poly(2-oxazoline)s with different side chains, namely methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, phenyl and benzyl, are reported in ethanol-water solvent mixtures based on turbidimetry investigations. The LCST transitions of poly(2-oxazoline) s with propyl side chains and the UCST transitions of the poly(2-oxazoline) s with more hydrophobic side chains are discussed in relation to the ethanol-water solvent composition and structure. The poly(2-alkyl-2-oxazoline) s with side chains longer than propyl only dissolved during the first heating run, which is discussed and correlated to the melting transition of the polymers

    A Subaru Weak Lensing Survey I: Cluster Candidates and Spectroscopic Verification

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    We present the results of an ongoing weak lensing survey conducted with the Subaru telescope whose initial goal is to locate and study the distribution of shear-selected structures or halos. Using a Suprime-cam imaging survey spanning 21.82 square degree, we present a catalog of 100 candidate halos located from lensing convergence maps. Our sample is reliably drawn from that subset of our survey area, (totaling 16.72 square degree) uncontaminated by bright stars and edge effects and limited at a convergence signal to noise ratio of 3.69. To validate the sample detailed spectroscopic measures have been made for 26 candidates using the Subaru multi-object spectrograph, FOCAS. All are confirmed as clusters of galaxies but two arise as the superposition of multiple clusters viewed along the line of sight. Including data available in the literature and an ongoing Keck spectroscopic campaign, a total of 41 halos now have reliable redshifts. For one of our survey fields, the XMM LSS (Pierre et al. 2004) field, we compare our lensing-selected halo catalog with its X-ray equivalent. Of 15 halos detected in the XMM-LSS field, 10 match with published X-ray selected clusters and a further 2 are newly-detected and spectroscopically confirmed in this work. Although three halos have not yet been confirmed, the high success rate within the XMM-LSS field (12/15) confirms that weak lensing provides a reliable method for constructing cluster catalogs, irrespective of the nature of the constituent galaxies or the intracluster medium.Comment: To appear in ApJ, High resolution preprint available at http://anela.mtk.nao.ac.jp/suprime33/papers/p1.ps.g

    First report of multinodular pulmonary fibrosis associated with equine herpesvirus 5 in Belgium

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    A 20-year-old horse was evaluated for symptoms of weight loss, anorexia, fever and lethargy. Clinical examination revealed tachypnea, poor body condition and increased breath sounds on auscultation. Ultrasound showed multiple consolidations on the lungs. Thoracic radiography revealed a severe nodular pattern. The horse was treated with antibiotics, corticoids and supportive medication. Since no improvement was observed, the horse was euthanized. At necropsy, numerous coalescing fibrous nodules were present in the lungs. Histology revealed diffuse interstitial fibrosis and macrophages containing abundant eosinophilic cytoplasm and oval eosinophilic to amphophilic intranuclear inclusion bodies. Tissue samples tested positive for the presence of equine herpes virus 5 (EHV 5) on the basis of the polymerase chain reaction (PCR) test. A diagnosis of equine multinodular pulmonary fibrosis (EMPF) was made. This is the first report of EMPF in Belgium. EMPF can be suspected based on the ultrasonographic, radiographic and histological changes. EMPF is associated with EHV 5, but the etiological role of EHV 5 still remains to be proven

    Digital games for 21st–century learning: Teacher librarians\u27 beliefs and practices

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    Video games as tools for learning in K-12 have been a topic of intense discussion over the past fifteen years. One area of focus has been on the integration of commercial off-the-shelf games in lesson plans. A predictive factor for the adoption and diffusion of this innovation is the attitudes or readiness of teachers. Yet while many studies have examined this with teachers themselves, teacher librarians (TLs) have largely been ignored, despite their key role in education and technology adoption in schools. This study examines the beliefs and practices of TLs concerning digital games as learning tools to determine if and how they differ from teachers with regard to games and learning. The Teachers\u27 Attitudes toward Games (TATG) survey measured TLs\u27 perceptions of barriers to using digital games. Findings suggest that TLs tend to use digital games to address discrete library skills, although there is evidence that some use games to integrate twenty-first-century skills into classroom lessons. Similar to findings on classroom teachers, TLs perceived lack of time, lack of infrastructure, and lack of support as barriers to using digital games
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