1,268 research outputs found

    A Deep Multicolor Survey I. Imaging Observations and Catalog of Stellar Objects

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    We have used the KPNO 4-meter Mayall telescope to image 0.83 square degrees of sky in six fields at high galactic latitude in six filters spanning 3000-10000\AA\ to magnitude limits ranging from 22.1 to 23.8. We have assembled a catalog of 21,375 stellar objects detected in the fields for use primarily in conducting a multicolor search for quasars. This paper describes the data reduction techniques used on the CCD data, the methods used to construct the stellar object catalog, and the simulations performed to understand its completeness and contamination.Comment: To Appear in ApJ Supplement, 1996. 168k uuencoded gunzipped tarred tex file (requires aas2pp4.sty and tighten.sty) and 4 PostScript figures. Also available at http://astro.as.arizona.edu/~pathall/astro.html#preprint

    Students’ Perceptions of Factors that Affect College Funding Decisions

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    This exploratory study examines the factors that college students perceive are important in helping them make good financial decisions about paying for a college education. The study categorizes and summarizes students\u27 self-reported responses to an openended survey question about recommendations for changes in financial aid counseling practices. The 335 student responses had a recurring theme of better information provided through individual counseling sessions

    Instabilities in complex mixtures with a large number of components

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    Inside living cells are complex mixtures of thousands of components. It is hopeless to try to characterise all the individual interactions in these mixtures. Thus, we develop a statistical approach to approximating them, and examine the conditions under which the mixtures phase separate. The approach approximates the matrix of second virial coefficients of the mixture by a random matrix, and determines the stability of the mixture from the spectrum of such random matrices.Comment: 4 pages, uses RevTeX 4.

    The ferrimagnetic compounds CoM[M'(EDTA)]2.4H2O (M,M'=Co,Ni): Magnetic characterization of CoCo[Ni(EDTA)]2.4H2O

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    Under the terms of the Creative Commons Attribution (CC BY) license to their work.We report on the magnetic properties of the ordered bimetallic compound CoCo(NiEDTA)2⋅4H2O (abbreviated as [CoCoNi]). The structure consists of ordered bimetallic layers formed by alternating octahedral sites of Co and Ni(II); tetrahedral Co sites connect different Co‐Ni layers. We discuss the low‐dimensional ferrimagnetic behavior of this compound in terms of a model that assumes three spin sublattices exchange coupled by an Ising interaction.This work was supported by the Comision Interministerial en Ciencia y Tecnologia (Grant No. PB 85-OI06-C02-02), the Iustitucio Valenciana d'Estudis i Investigació, and the National Science Foundation (Grant No. DMR-8515224). F. S. andP. G. R. thank the Spanish Ministerio de Educacion y Ciencia for a predoctoral and postdoctoral fellowship, respectively.Peer Reviewe

    A Deep Multicolor Survey II. Initial Spectroscopy and Comparison With Expected Quasar Number Counts

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    We have used the KPNO 4-meter Mayall telescope to image 0.83 square degrees of sky in six fields at high galactic latitude in six filters spanning 3000-10000\AA\ to magnitude limits ranging from 22.1 to 23.8. As a first use of this database, we have conducted a multicolor survey for quasars. We discuss various methods of selecting outliers in different color-color diagrams and multicolor space that have been used to identify quasars at all redshifts from their colors alone. We discuss the initial results of our program of spectroscopic identification which has so far resulted in the identification of over forty faint quasars, including one at z>>4, a similar number of compact narrow-emission-line galaxies, and a number of unusual and potentially interesting stars. We use these spectroscopic results, along with extensive simulations of quasar spectra, to study the efficiency of our candidate selection procedures. Finally, we compare the number counts of our quasars and quasar candidates to the expected numbers based on previous studies of the quasar luminosity function. The agreement of our observations with these expectations is good in most cases. However, we do estimate that our survey contains more quasars with B<<21 and z<<2.3 than expected from the results of Koo \& Kron (1988) and more z>>3 quasars than expected from the results of Warren, Hewett, \& Osmer (1994), both at the 3σ\sigma\ level. Additional spectroscopic observations will be required to confirm or refute these excesses.Comment: To appear in ApJ Vol. 462, May 20, 1996. 87k gunzipped uuencoded PostScript file. Figures (2750k) available from http://astro.as.arizona.edu/~pathall/astro.html#preprints or via anonymous ftp to ftp://gemini.tuc.noao.edu/pub/phall/ or by email to [email protected]

    Oral ferroportin inhibitor vamifeport for improving iron homeostasis and erythropoiesis in β-thalassemia: current evidence and future clinical development

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    Introduction: In β-thalassemia, imbalanced globin synthesis causes reduced red blood cell survival and ineffective erythropoiesis. Suppressed hepcidin levels increase ferroportin-mediated iron transport in enterocytes, causing increased iron absorption and potentially iron overload. Low hepcidin also stimulates ferroportin-mediated iron release from macrophages, increasing transferrin saturation (TSAT), potentially forming non-transferrin-bound iron, which can be toxic. Modulating the hepcidin–ferroportin axis is an attractive strategy to improve ineffective erythropoiesis and limit the potential tissue damage resulting from iron overload. There are no oral β-thalassemia treatments that consistently ameliorate anemia and prevent iron overload. / Areas covered: The preclinical and clinical development of vamifeport (VIT-2763), a novel ferroportin inhibitor, was reviewed. PubMed, EMBASE and ClinicalTrials.gov were searched using the search term ‘VIT-2763ʹ. / Expert opinion: Vamifeport is the first oral ferroportin inhibitor in clinical development. In healthy volunteers, vamifeport had comparable safety to placebo, was well tolerated and rapidly decreased iron levels and reduced TSAT, consistent with observations in preclinical models. Data from ongoing/planned Phase II studies are critical to define its potential in β-thalassemia and other conditions associated with iron overabsorption and/or ineffective erythropoiesis. If vamifeport potentially increases hemoglobin and reduces iron-related parameters, it could be a suitable treatment for non-transfusion-dependent and transfusion-dependent β-thalassemia

    Challenges and opportunities of achieving European CO₂ transportation and storage specifications for carbon capture in the iron and steel industry

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    The application of CCS in the iron and steel industry faces particular challenges for achieving European CO2 transportation and storage in meeting CO₂ stream impurity limit specifications due to the unique and diverse composition of the steelworks off-gases targeted for CO₂ capture and the separation efficiency of proposed CO₂ capture solutions. This paper reviews the range and levels of compounds that could form potential CO₂ impurities in steelworks off-gases and provides estimates of the quality of CO₂ products obtained in primary CO₂ capture steps from Blast Furnace Gas (BFG) using different technologies of Pressure-Swing Adsorption (PSA) and amine scrubbing. Published CO₂ specifications from European transportation and storage operators are reviewed and compared. Additional suitable purification steps that are needed in order to reduce the levels of impurities from primary CO₂ product streams in order to achieve European CO₂ impurity limit specifications are identified, characterised and the associated cost implications discussed

    Attenuation of dengue virus infection by adeno-associated virus-mediated siRNA delivery

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    BACKGROUND: The need for safe and effective treatment of dengue virus (DEN), a class A agent that causes dengue hemorrhagic fever/dengue shock syndrome, has been a critical global priority. An effective vaccine for DEN is not yet available. In this study the possibility of attenuating DEN infection using adeno-associated virus (AAV)-encoded short interfering RNAs (siRNA) was examined in Vero cells and human dendritic cells (DCs). METHODS: A cassette encoding siRNA targeted to a 3' untranslated sequence common to all DEN serotypes was designed and tested for its ability to attenuate DEN infection by use of AAV delivery. RESULTS: Vero cells or DCs infected with AAV-siRNA showed a significant, dose-dependent reduction in DEN infection. Treatment of DCs with AAV-siRNA also decreased the DEN-induced apoptosis of DCs and did not induce significant inflammation. CONCLUSION: These results demonstrate that AAV-mediated siRNA delivery is capable of reducing DEN infection in cells and may be useful in decreasing DEN replication in humans
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