619 research outputs found

    RARITAN FORMATION (UPPER CRETACEOUS), LONG ISLAND, NEW YORK: SEDIMENTOLOGICAL AND GEOCHEMICAL ASSESSMENT

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    The lithology of the Upper Cretaceous Raritan Formation (RF) consists of two members: an upper clay member (Raritan clay) and a lower unit, the Lloyd Sand Member. RF is unconformably overlain by upper Pleistocene glacial deposits. The RF consists of stratified white, light- to dark-gray, and red beds and lenses of clay, silt, and sand; lignite and pyrite are common. Variegated, thin to thickly-bedded Lloyd sandstone (LS) is considered to be one of the extensive regional aquifers in Long Island and interpreted to be nearshore, fluvio-deltaic deposit. Proximity to fluvial axes and active deltaic lobes plays an important role in sequence thickness and maintaining an overall architecture of deltaic sandbodies. Presumably large amounts of deltaically derived sand are reworked by wave action and redistributed by longshore currents. LS is generally identified as containing clayey lenses, pyrite and hematitic, highly micaceous reddish silty sandstone. Its upper surface lies about 400 feet below sea level in northwest Huntington and at Orient, and over 1,500 feet below sea level at western Fire Island. The exposed unit is about 30 m thick in Caumsett State Park, Long Island. Preliminary geochemical investigations using ICP-MS (Inductively coupled plasma mass spectrometry), Ultra Trace Aqua Regia ICP-MS, and routine petrography on selected samples (both outcrop and subsurface) revealed a distinctive geochemical signature associated with RF units (Raritan Clay and Lloyd Sandstone). Clay unit known as Raritan Clay contains 60-42% silica, 27-15% alumina, 7% iron-oxide, and 3% K2O, whereas LS is found to be dominantly silica rich (97%) and remarkably poor in alumina, iron-oxide, and K2O. RF clayey unit also showed LOI to be 7-40%. Field exposure of RF clay resembles a kaolinitic-illitic type of high plasticity. Selected trace elements were identified and include Zr, Cu, Ti, Rb, La, Ba, Sr, Ce, Cr, Y, and Zn. Clayey units in RF were found to contain significantly higher proportion of Cu (80-30 ppm), Rb (35-15 ppm), Ba (80-40 ppm), Ce (105 ppm), Cr (60-20 ppm), Y (30 ppm) and Zn (200-40 ppm), compared to LS. Distinctive geochemical variations between the RF clay and LS point to variable provenance, diagenetic pathways, and depositional environments. Further investigations will proceed to differentiate subunits within the LS and RF clayey unit

    A Constrained Standard Model from a Compact Extra Dimension

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    A SU(3) \times SU(2) \times U(1) supersymmetric theory is constructed with a TeV sized extra dimension compactified on the orbifold S^1/(Z_2 \times Z_2'). The compactification breaks supersymmetry leaving a set of zero modes which correspond precisely to the states of the 1 Higgs doublet standard model. Supersymmetric Yukawa interactions are localized at orbifold fixed points. The top quark hypermultiplet radiatively triggers electroweak symmetry breaking, yielding a Higgs potential which is finite and exponentially insensitive to physics above the compactification scale. This potential depends on only a single free parameter, the compactification scale, yielding a Higgs mass prediction of 127 \pm 8 GeV. The masses of the all superpartners, and the Kaluza-Klein excitations are also predicted. The lightest supersymmetric particle is a top squark of mass 197 \pm 20 GeV. The top Kaluza-Klein tower leads to the \rho parameter having quadratic sensitivity to unknown physics in the ultraviolet.Comment: 31 pages, Latex, 2 eps figures, minor correction

    Challenges to evidence synthesis and identification of data gaps in human biomonitoring

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    The increasing number of human biomonitoring (HBM) studies undertaken in recent decades has brought to light the need to harmonise procedures along all phases of the study, including sampling, data collection and analytical methods to allow data comparability. The first steps towards harmonisation are the identification and collation of HBM methodological information of existing studies and data gaps. Systematic literature reviews and meta-analyses have been traditionally put at the top of the hierarchy of evidence, being increasingly applied to map available evidence on health risks linked to exposure to chemicals. However, these methods mainly capture peer-reviewed articles, failing to comprehensively identify other important, unpublished sources of information that are pivotal to gather a complete map of the produced evidence in the area of HBM. Within the framework of the European Human Biomonitoring Initiative (HBM4EU) initiative—a project that joins 30 countries, 29 from Europe plus Israel, the European Environment Agency and the European Commission—a comprehensive work of data triangulation has been made to identify existing HBM studies and data gaps across countries within the consortium. The use of documentary analysis together with an up-to-date platform to fulfil this need and its implications for research and practice are discussed

    U(1) textures and Lepton Flavor Violation

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    U(1) family symmetries have led to successful predictions of the fermion mass spectrum and the mixing angles of the hadronic sector. In the context of the supersymmetric unified theories, they further imply a non-trivial mass structure for the scalar partners, giving rise to new sources of flavor violation. In the present work, lepton flavor non-conserving processes are examined in the context of the minimal supersymmetric standard model augmented by a U(1)-family symmetry. We calculate the mixing effects on the \mu-> e\gamma and \tau -> \mu\gamma rare decays. All supersymmetric scalar masses involved in the processes are determined at low energies using two loop renormalization group analysis and threshold corrections. Further, various novel effects are considered and found to have important impact on the branching ratios. Thus, a rather interesting result is that when the see-saw mechanism is applied in the (12 X 12)-sneutrino mass matrix, the mixing effects of the Dirac matrix in the effective light sneutrino sector are canceled at first order. In this class of models and for the case that soft term mixing is already present at the GUT scale, tau -> \mu \gamma decays are mostly expected to arise at rates significantly smaller than the current experimental limits. On the other hand, the \mu \ra e \gamma rare decays impose important bounds on the model parameters, particularly on the supersymmetric scalar mass spectrum. In the absence of soft term mixing at high energies, the predicted branching ratios for rare decays are, as expected, well below the experimental bounds.Comment: 24p, 10 figures, version to appear in Phys. Rev.

    The ACOS CO_2 retrieval algorithm – Part 1: Description and validation against synthetic observations

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    This work describes the NASA Atmospheric CO_2 Observations from Space (ACOS) X_(CO_2) retrieval algorithm, and its performance on highly realistic, simulated observations. These tests, restricted to observations over land, are used to evaluate retrieval errors in the face of realistic clouds and aerosols, polarized non-Lambertian surfaces, imperfect meteorology, and uncorrelated instrument noise. We find that post-retrieval filters are essential to eliminate the poorest retrievals, which arise primarily due to imperfect cloud screening. The remaining retrievals have RMS errors of approximately 1 ppm. Modeled instrument noise, based on the Greenhouse Gases Observing SATellite (GOSAT) in-flight performance, accounts for less than half the total error in these retrievals. A small fraction of unfiltered clouds, particularly thin cirrus, lead to a small positive bias of ~0.3 ppm. Overall, systematic errors due to imperfect characterization of clouds and aerosols dominate the error budget, while errors due to other simplifying assumptions, in particular those related to the prior meteorological fields, appear small

    Photodynamic Therapy of Tumors Can Lead to Development of Systemic Antigen-Specific Immune Response

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    Background: The mechanism by which the immune system can effectively recognize and destroy tumors is dependent on recognition of tumor antigens. The molecular identity of a number of these antigens has recently been identified and several immunotherapies have explored them as targets. Photodynamic therapy (PDT) is an anti-cancer modality that uses a non-toxic photosensitizer and visible light to produce cytotoxic reactive oxygen species that destroy tumors. PDT has been shown to lead to local destruction of tumors as well as to induction of anti-tumor immune response. Methodology/Principal Findings: We used a pair of equally lethal BALB/c colon adenocarcinomas, CT26 wild-type (CT26WT) and CT26.CL25 that expressed a tumor antigen, β-galactosidase (β-gal), and we treated them with vascular PDT. All mice bearing antigen-positive, but not antigen-negative tumors were cured and resistant to rechallenge. T lymphocytes isolated from cured mice were able to specifically lyse antigen positive cells and recognize the epitope derived from beta-galactosidase antigen. PDT was capable of destroying distant, untreated, established, antigen-expressing tumors in 70% of the mice. The remaining 30% escaped destruction due to loss of expression of tumor antigen. The PDT anti-tumor effects were completely abrogated in the absence of the adaptive immune response. Conclusion: Understanding the role of antigen-expression in PDT immune response may allow application of PDT in metastatic as well as localized disease. To the best of our knowledge, this is the first time that PDT has been shown to lead to systemic, antigen- specific anti-tumor immunity.United States. National Cancer Institute (grant RO1CA/AI838801)United States. National Cancer Institute (grant R01AI050875

    Production and Decay of Scalar Stoponium Bound States

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    In this paper we discuss possible signatures for the production of scalar \stst\ (stoponium) bound states \sigst\ at hadron colliders, where \st\ is the lighter scalar top eigenstate. We first study the decay of \sigst; explicit expressions are given for all potentially important decay modes. If \st\ has unsuppressed two--body decays, they will always overwhelm the annihilation decays of \sigst. Among the latter, we find that usually either the gggg or hhhh final state dominates, depending on the size of the off--diagonal entry of the stop mass matrix; hh is the lighter neutral scalar Higgs boson of the minimal supersymmetric model. If \msig\ happens to be close to the mass of one of the neutral scalar Higgs bosons, QQˉQ \bar{Q} final states dominate (Q=bQ=b or tt). \ww\ and ZZZZ final states are subdominant. We argue that \sigst \rightarrow \gamgam decays offer the best signal for stoponium production at hadron colliders. The tevatron should be able to close the light stop window left open by LEP searches, but its mass reach is limited to \msig \leq 90 GeV. In contrast, at the LHC one should ultimately be able to probe the region \msig \leq 700 GeV, if the hhhh partial width is not too large. We also comment on the feasibility of searching for \sigst\ production at hadron colliders in the ZZ, ZγZZ, \ Z \gamma and \fourtau\ final states, and briefly mention \sigst\ production at \gamgam\ colliders.Comment: 31 pages plus 10 figures (available from DREES@WISCPHEN); LaTeX with equation.sty; MAD/PH/808, KEK-TH-37
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