24 research outputs found

    Influence Of Unusual Economic Conditions On The Occurrence Of The Size Anomaly

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    Much of the explanation for the size anomaly has been assigned to taxation and behavioural issues near the end of the calendar year. However, factor models based on company characteristics suggest that some type of risk may also have a long term effect on returns.  We use a traditional multifactor model to re-examine the influence of macroeconomic variables on the magnitude and direction of size portfolio returns using traditional and Logit regression models. Our results indicate significant differences in sensitivity of returns to the market risk factor across size portfolios, but limited mean return effects of economic and financial factors. However, we find that macroeconomic factors that take on unusually extreme values influence the probable direction of annual size anomalies.  The unusual economic conditions may influence investor risk-return expectations differentially across size portfolios. These differing expectations are reflected in the occurrence of a size anomaly

    Quantum Gas Mixtures and Dual-Species Atom Interferometry in Space

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    The capability to reach ultracold atomic temperatures in compact instruments has recently been extended into space. Ultracold temperatures amplify quantum effects, while free-fall allows further cooling and longer interactions time with gravity - the final force without a quantum description. On Earth, these devices have produced macroscopic quantum phenomena such as Bose-Einstein condensation (BECs), superfluidity, and strongly interacting quantum gases. Quantum sensors interfering the superposition of two ultracold atomic isotopes have tested the Universality of Free Fall (UFF), a core tenet of Einstein's classical gravitational theory, at the 101210^{-12} level. In space, cooling the elements needed to explore the rich physics of strong interactions and preparing the multiple species required for quantum tests of the UFF has remained elusive. Here, utilizing upgraded capabilities of the multi-user Cold Atom Lab (CAL) instrument within the International Space Station (ISS), we report the first simultaneous production of a dual species Bose-Einstein condensate in space (formed from 87^{87}Rb and 41^{41}K), observation of interspecies interactions, as well as the production of 39^{39}K ultracold gases. We have further achieved the first space-borne demonstration of simultaneous atom interferometry with two atomic species (87^{87}Rb and 41^{41}K). These results are an important step towards quantum tests of UFF in space, and will allow scientists to investigate aspects of few-body physics, quantum chemistry, and fundamental physics in novel regimes without the perturbing asymmetry of gravity

    UBVRI Light Curves of 44 Type Ia Supernovae

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    We present UBVRI photometry of 44 type-Ia supernovae (SN Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SN Ia to date, nearly doubling the number of well-observed, nearby SN Ia with published multicolor CCD light curves. The large sample of U-band photometry is a unique addition, with important connections to SN Ia observed at high redshift. The decline rate of SN Ia U-band light curves correlates well with the decline rate in other bands, as does the U-B color at maximum light. However, the U-band peak magnitudes show an increased dispersion relative to other bands even after accounting for extinction and decline rate, amounting to an additional ~40% intrinsic scatter compared to B-band.Comment: 84 authors, 71 pages, 51 tables, 10 figures. Accepted for publication in the Astronomical Journal. Version with high-res figures and electronic data at http://astron.berkeley.edu/~saurabh/cfa2snIa

    Eosinophils in glioblastoma biology

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    Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. The development of this malignant glial lesion involves a multi-faceted process that results in a loss of genetic or epigenetic gene control, un-regulated cell growth, and immune tolerance. Of interest, atopic diseases are characterized by a lack of immune tolerance and are inversely associated with glioma risk. One cell type that is an established effector cell in the pathobiology of atopic disease is the eosinophil. In response to various stimuli, the eosinophil is able to produce cytotoxic granules, neuromediators, and pro-inflammatory cytokines as well as pro-fibrotic and angiogenic factors involved in pathogen clearance and tissue remodeling and repair. These various biological properties reveal that the eosinophil is a key immunoregulatory cell capable of influencing the activity of both innate and adaptive immune responses. Of central importance to this report is the observation that eosinophil migration to the brain occurs in response to traumatic brain injury and following certain immunotherapeutic treatments for GBM. Although eosinophils have been identified in various central nervous system pathologies, and are known to operate in wound/repair and tumorstatic models, the potential roles of eosinophils in GBM development and the tumor immunological response are only beginning to be recognized and are therefore the subject of the present review

    The epimerization of α-chiral hydrazones: Menthonetosylhydrazone

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    The first preparation of (-)-menthonetosylhydrazone (2) in diastereomerically pure form is reported. Kinetic studies show that 2 is far more susceptible to acid-catalyzed epimerization (∼150x) than is the parent ketone, (-)-menthone (1), a relationship which has not been generally recognized. Conversion of 2 to 1-menthenyllithium (3) using excess butyllithium occurs without detectable epimerization, as determined by analysis of the 1-iodomenthene 5 obtained by treatment of 3 with iodine in-situ. © 1993
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