444 research outputs found

    Blood Protein Residues on Lithic Artifacts from Two Archaeological Sites in the De Long Mountains, Northwestern Alaska

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    Immunological analysis of blood residues was performed on 25 lithic artifacts from two archaeological sites (DEL-166 and DEL-168) in the De Long Mountains of northwestern Alaska. Blood residues occur on five artifact types: retouched flakes; end scrapers; flake burins; bifaces; and wedge-shaped microblade cores. Fourteen (56%) of the 25 analyzed artifacts react positively to six animal antisera and to human blood. Besides human blood, identified residues include the blood of sturgeon (Acipenseridae), deer (Cervidae), rabbit (Leporidae), bear (Ursus), "cat" (Felidae) and "mouse" (Rodentia). Although the application of blood residue analysis to archaeological problems is a relatively new application of an old forensic method, it may provide useful information about artifact function and animal procurement from sites where faunal remains are not preserved.On a procédé à une analyse immunologique de résidus sanguins sur 25 artefacts lithiques provenant de deux sites archéologiques (DEL-166 et DEL-168) dans les monts De Long du nord-ouest de l'Alaska. On a trouvé des résidus sanguins sur cinq types d'artefacts: éclats retouchés; grattoirs sur lame; burins faits d'éclats; bifaces; et nucléus microlames cunéiformes. Quatorze (56 p. cent) des 25 artefacts analysés ont réagi positivement à six antisérums de provenance animale et à du sang humain. Outre le sang de provenance humaine, les résidus identifiés comprennent le sang d'esturgeon (Acipenseridae), de chevreuil (Cervidae), de lapin (Leporidae), d'ours (Ursus), de «chat» (Felidae) et de «souris» (Rodentia). Bien que l'application de l'analyse de résidus sanguins à des questions d'ordre archéologique soit une application relativement nouvelle d'une ancienne méthode médico-légale, elle peut fournir des renseignements utiles sur la fonction de l'artefact et sur l'approvisionnement en animaux dans les cas de sites où les vestiges de la faune n'ont pas été conservés

    Two Rare Magnetic Cataclysmic Variables with Extreme Cyclotron Features Identified in the Sloan Digital Sky Survey

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    Two newly identified magnetic cataclysmic variables discovered in the Sloan Digital Sky Survey (SDSS), SDSSJ155331.12+551614.5 and SDSSJ132411.57+032050.5, have spectra showing highly prominent, narrow, strongly polarized cyclotron humps with amplitudes that vary on orbital periods of 4.39 and 2.6 hrs, respectively. In the former, the spacing of the humps indicates the 3rd and 4th harmonics in a magnetic field of ~60 MG. The narrowness of the cyclotron features and the lack of strong emission lines imply very low temperature plasmas and very low accretion rates, so that the accreting area is heated by particle collisions rather than accretion shocks. The detection of rare systems like these exemplifies the ability of the SDSS to find the lowest accretion rate close binaries.Comment: Accepted for publication in the Astrophysical Journal, vol. 583, February 1, 2003; slight revisions and additions in response to referee's comments; 17 pages, 6 figures, AASTeX v4.

    A Qualitative Study of an Integrated Maternity, Drugs and Social Care Service for Drug-using Women

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    Background: The care of drug-using pregnant women is a growing health and social care concern in many countries. A specialist clinic was established offering multidisciplinary care and advice to pregnant drug users in and around Aberdeen (UK) in 1997. The majority of women stabilise and reduce their drug use. By determining the needs and views of the women more appropriate services and prevention strategies may be developed. There has been little research conducted in this area and none in Scotland. Methods: This is a qualitative study that aimed to gain an understanding of the experiences of women drug users, seeking and receiving prenatal care and drug services from a specialist clinic. Twelve women participated in semi-structured one-to-one interviews. Results: The women preferred the multidisciplinary clinic (one-stop shop) to traditional prenatal care centred within General Practice. The relationships of the clients to the range of Clinic professionals and in hospital were explored as well as attitudes to Clinic care. The study participants attributed success in reducing their drug use to the combination of different aspects of care of the multi-agency clinic, especially the high level prenatal support. It is this arrangement of all aspects of care together that seem to produce better outcomes for mother and child than single care elements delivered separately. Some women reported that their pregnancy encouraged them to rapidly detoxify due to the guilt experienced. The most important aspects of the Clinic care were found to be non-judgemental attitude of staff, consistent staff, high level of support, reliable information and multi-agency integrated care. Conclusion: There is an impetus for women drug users to change lifestyle during pregnancy. The study highlighted a need for women to have access to reliable information on the effects of drugs on the baby. Further research is required to determine whether positive outcomes related to clinic attendance in the prenatal period are sustained in the postnatal period. Early referral to a specialist clinic is of benefit to the women, as they reported to receive more appropriate care, especially in relation to their drug use. A greater awareness of needs of the pregnant drug user could help the design of more effective prevention strategies

    The Sloan Digital Sky Survey Quasar Lens Search. II. Statistical lens sample from the third data release

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    We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46,420 quasars from the SDSS Data Release 3 (~4188 deg^2), we select a subsample of 22,683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic extinction-corrected i-band magnitude of 19.1. We identify 220 lens candidates from the quasar subsample, for which we conduct extensive and systematic follow-up observations in optical and near-infrared wavebands, in order to construct a complete lensed quasar sample at image separations between 1" and 20" and flux ratios of faint to bright lensed images larger than 10^(−0.5). We construct a statistical sample of 11 lensed quasars. Ten of these are galaxy-scale lenses with small image separations (~ 1"-2") and one is a large separation (15") system which is produced by a massive cluster of galaxies, representing the first statistical sample of lensed quasars including both galaxy- and cluster-scale lenses. The Data Release 3 spectroscopic quasars contain an additional 11 lensed quasars outside the statistical sample

    Ozone depletion due to dust release of iodine in the free troposphere

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    Iodine is an atmospheric trace element emitted from oceans that efficiently destroys ozone (O3). Low O3 in airborne dust layers is frequently observed but poorly understood. We show that dust is a source of gas-phase iodine, indicated by aircraft observations of iodine monoxide (IO) radicals inside lofted dust layers from the Atacama and Sechura Deserts that are up to a factor of 10 enhanced over background. Gas-phase iodine photochemistry, commensurate with observed IO, is needed to explain the low O3 inside these dust layers (below 15 ppbv; up to 75% depleted). The added dust iodine can explain decreases in O3 of 8% regionally and affects surface air quality. Our data suggest that iodate reduction to form volatile iodine species is a missing process in the geochemical iodine cycle and presents an unrecognized aeolian source of iodine. Atmospheric iodine has tripled since 1950 and affects ozone layer recovery and particle formation.Fil: Koenig, Theodore K.. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados UnidosFil: Volkamer, Rainer. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados UnidosFil: Apel, Eric C.. National Center for Atmospheric Research; Estados UnidosFil: Bresch, James F.. National Center for Atmospheric Research; Estados UnidosFil: Cuevas, Carlos A.. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; EspañaFil: Dix, Barbara. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados UnidosFil: Eloranta, Edwin W.. University of Wisconsin; Estados UnidosFil: Fernandez, Rafael Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Hall, Samuel R.. National Center for Atmospheric Research; Estados UnidosFil: Hornbrook, Rebecca S.. National Center for Atmospheric Research; Estados UnidosFil: Pierce, R. Bradley. National Environmental Satellite, Data, and Information Service; Estados UnidosFil: Reeves, J. Michael. National Center for Atmospheric Research; Estados UnidosFil: Saiz López, Alfonso. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; EspañaFil: Ullmann, Kirk. National Center for Atmospheric Research; Estados Unido

    Criminology or Zemiology? Yes, please! on the refusal of choice between false alternatives

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    Buried deep within the zemiological movement and its supportive literature is the implicit assumption that the word zemia, the organising concept around which zemiology is built, simply represents ‘the Greek word for harm’. This interpretation has supported numerous drives to ‘move beyond criminology’ and erect strict borders between the study of crime and harm. However, a deeper, albeit still rather brief, exploration of zemia reveals that it possesses a broader range of meaning than that commonly afforded to it. By beginning to unpick zemia’s semantic genealogy, it appears that the conventional use of the word to support the imposition of false alternatives between criminology and zemiology is untenable. Accordingly, this chapter attempts to foreground a more integrated approach to the study of crime and harm

    The role of triplet states in the long wavelength absorption region of bromine nitrate

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    A theoretical study of the low-lying singlet and triplet electronic states of BrONO 2 is presented. Calculations of excitation energies and oscillator strengths are reported using excited-state coupled cluster response methods, as well as the complete active space self-consistent field method with the full Breit-Pauli spin-orbit operator. The calculations predict that there is only one singlet state for BrONO 2 , the à 1 AЉ state, that is accessible at wavelengths longer than 300 nm. At energies below the first singlet state, i.e., Ͼ330 nm, the calculations reveal two triplet states with significant oscillator strength. Therefore, we propose that the origin of absorption in the long wavelength region from 350 to 500 nm, responsible for the majority of atmospheric photolysis, is due to transitions to triplet states and not singlet states. A comparison of the reported benchmark coupled cluster calculations ͑CCSD͒ with the results of ͑1͒ configuration interaction with all single substitutions and a perturbative correction for the double substitutions ͓CIS͑D͔͒ and ͑2͒ time-dependent density-functional ͑TDDF͒ calculations is provided. For the lowest energy excitations, CIS͑D͒ calculations provide quantitative agreement with the CCSD results, while TDDF calculations yield qualitative agreement

    The Sloan Digital Sky Survey Quasar Lens Search. III. Constraints on Dark Energy from the Third Data Release Quasar Lens Catalog

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    We present cosmological results from the statistics of lensed quasars in the Sloan Digital Sky Survey (SDSS) Quasar Lens Search. By taking proper account of the selection function, we compute the expected number of quasars lensed by early-type galaxies and their image separation distribution assuming a flat universe, which is then compared with 7 lenses found in the SDSS Data Release 3 to derive constraints on dark energy under strictly controlled criteria. For a cosmological constant model (w=-1) we obtain \Omega_\Lambda=0.74^{+0.11}_{-0.15}(stat.)^{+0.13}_{-0.06}(syst.). Allowing w to be a free parameter we find \Omega_M=0.26^{+0.07}_{-0.06}(stat.)^{+0.03}_{-0.05}(syst.) and w=-1.1\pm0.6(stat.)^{+0.3}_{-0.5}(syst.) when combined with the constraint from the measurement of baryon acoustic oscillations in the SDSS luminous red galaxy sample. Our results are in good agreement with earlier lensing constraints obtained using radio lenses, and provide additional confirmation of the presence of dark energy consistent with a cosmological constant, derived independently of type Ia supernovae.Comment: 9 pages, 3 figures, 2 tables, accepted for publication in A

    Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

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    The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

    Seasonal melting and the formation of sedimentary rocks on Mars, with predictions for the Gale Crater mound

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    A model for the formation and distribution of sedimentary rocks on Mars is proposed. The rate-limiting step is supply of liquid water from seasonal melting of snow or ice. The model is run for a O(10^2) mbar pure CO2 atmosphere, dusty snow, and solar luminosity reduced by 23%. For these conditions snow only melts near the equator, and only when obliquity >40 degrees, eccentricity >0.12, and perihelion occurs near equinox. These requirements for melting are satisfied by 0.01-20% of the probability distribution of Mars' past spin-orbit parameters. Total melt production is sufficient to account for aqueous alteration of the sedimentary rocks. The pattern of seasonal snowmelt is integrated over all spin-orbit parameters and compared to the observed distribution of sedimentary rocks. The global distribution of snowmelt has maxima in Valles Marineris, Meridiani Planum and Gale Crater. These correspond to maxima in the sedimentary-rock distribution. Higher pressures and especially higher temperatures lead to melting over a broader range of spin-orbit parameters. The pattern of sedimentary rocks on Mars is most consistent with a Mars paleoclimate that only rarely produced enough meltwater to precipitate aqueous cements and indurate sediment. The results suggest intermittency of snowmelt and long globally-dry intervals, unfavorable for past life on Mars. This model makes testable predictions for the Mars Science Laboratory rover at Gale Crater. Gale Crater is predicted to be a hemispheric maximum for snowmelt on Mars.Comment: Submitted to Icarus. Minor changes from submitted versio
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