666 research outputs found

    Awareness and Use of Non-conventional Tobacco Products Among U.S. Students, 2012

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    BackgroundIncreasing diversity of the tobacco product landscape, including electronic cigarettes (e-cigarettes), hookah, snus, and dissolvable tobacco products (dissolvables), raises concerns about the public health impact of these non-conventional tobacco products among youth.PurposeThis study assessed awareness, ever use, and current use of non-conventional tobacco products among U.S. students in 2012, overall and by demographic and tobacco use characteristics.MethodsData from the 2012 National Youth Tobacco Survey, a nationally representative survey of U.S. middle and high school students, were analyzed in 2013. Prevalence of awareness, ever use, and current use of e-cigarettes, hookah, snus, and dissolvables were calculated overall and by sex, school level, race/ethnicity, and conventional tobacco product use, including cigarettes, cigars, or smokeless tobacco (chewing tobacco, snuff, or dip).ResultsOverall, 50.3% of students were aware of e-cigarettes; prevalence of ever and current use of e-cigarettes was 6.8% and 2.1%, respectively. Awareness of hookah was 41.2% among all students, and that of ever and current use were 8.9% and 3.6%, respectively. Overall awareness; ever; and current use of snus (32%, 5.3%, 1.7%, respectively) and dissolvables (19.3%, 2.0%, 0.7%, respectively) were generally lower than those of e-cigarettes or hookah. Conventional tobacco product users were more likely to be aware of and to use non-conventional tobacco products.ConclusionsMany U.S. students are aware of and use non-conventional tobacco products. Evidence-based interventions should be implemented to prevent and reduce all tobacco use among youth

    Targeting the HSP60/10 chaperonin systems of Trypanosoma brucei as a strategy for treating African sleeping sickness

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    Trypanosoma brucei are protozoan parasites that cause African sleeping sickness in humans (also known as Human African Trypanosomiasis—HAT). Without treatment, T. brucei infections are fatal. There is an urgent need for new therapeutic strategies as current drugs are toxic, have complex treatment regimens, and are becoming less effective owing to rising antibiotic resistance in parasites. We hypothesize that targeting the HSP60/10 chaperonin systems in T. brucei is a viable anti-trypanosomal strategy as parasites rely on these stress response elements for their development and survival. We recently discovered several hundred inhibitors of the prototypical HSP60/10 chaperonin system from Escherichia coli, termed GroEL/ES. One of the most potent GroEL/ES inhibitors we discovered was compound 1. While examining the PubChem database, we found that a related analog, 2e-p, exhibited cytotoxicity to Leishmania major promastigotes, which are trypanosomatids highly related to Trypanosoma brucei. Through initial counter-screening, we found that compounds 1 and 2e-p were also cytotoxic to Trypanosoma brucei parasites (EC50 = 7.9 and 3.1 μM, respectively). These encouraging initial results prompted us to develop a library of inhibitor analogs and examine their anti-parasitic potential in vitro. Of the 49 new chaperonin inhibitors developed, 39% exhibit greater cytotoxicity to T. brucei parasites than parent compound 1. While many analogs exhibit moderate cytotoxicity to human liver and kidney cells, we identified molecular substructures to pursue for further medicinal chemistry optimization to increase the therapeutic windows of this novel class of chaperonin-targeting anti-parasitic candidates. An intriguing finding from this study is that suramin, the first-line drug for treating early stage T. brucei infections, is also a potent inhibitor of GroEL/ES and HSP60/10 chaperonin systems

    Bombus griseocollis.

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    17 pages : illustrations ; 26 cm.This paper describes and illustrates the egg, fifth, first, and fourth larval instars, as well as the female pupa of Bombus (Cullumanobombus) griseocollis (DeGeer), all collected from a single nest in June 2017 in Wisconsin. In so doing, attempts are made to understand the biological significance of the anatomical and behavioral features of these various life stages

    A comprehensive database of quality-rated fossil ages for Sahul\u27s Quaternary vertebrates

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    The study of palaeo-chronologies using fossil data provides evidence for past ecological and evolutionary processes, and is therefore useful for predicting patterns and impacts of future environmental change. However, the robustness of inferences made from fossil ages relies heavily on both the quantity and quality of available data. We compiled Quaternary non-human vertebrate fossil ages from Sahul published up to 2013. This, the FosSahul database, includes 9,302 fossil records from 363 deposits, for a total of 478 species within 215 genera, of which 27 are from extinct and extant megafaunal species (2,559 records). We also provide a rating of reliability of individual absolute age based on the dating protocols and association between the dated materials and the fossil remains. Our proposed rating system identified 2,422 records with high-quality ages (i.e., a reduction of 74%). There are many applications of the database, including disentangling the confounding influences of hypothetical extinction drivers, better spatial distribution estimates of species relative to palaeo-climates, and potentially identifying new areas for fossil discovery

    Nucleon-Gold Collisions at 200 AGeV Using Tagged d+Au Interactions in PHOBOS

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    Forward calorimetry in the PHOBOS detector has been used to study charged hadron production in d+Au, p+Au and n+Au collisions at sqrt(s_nn) = 200 GeV. The forward proton calorimeter detectors are described and a procedure for determining collision centrality with these detectors is detailed. The deposition of energy by deuteron spectator nucleons in the forward calorimeters is used to identify p+Au and n+Au collisions in the data. A weighted combination of the yield of p+Au and n+Au is constructed to build a reference for Au+Au collisions that better matches the isospin composition of the gold nucleus. The p_T and centrality dependence of the yield of this improved reference system is found to match that of d+Au. The shape of the charged particle transverse momentum distribution is observed to extrapolate smoothly from pbar+p to central d+Au as a function of the charged particle pseudorapidity density. The asymmetry of positively- and negatively-charged hadron production in p+Au is compared to that of n+Au. No significant asymmetry is observed at mid-rapidity. These studies augment recent results from experiments at the LHC and RHIC facilities to give a more complete description of particle production in p+A and d+A collisions, essential for the understanding the medium produced in high energy nucleus-nucleus collisions.Comment: 17 pages, 18 figure

    Overfitting Affects the Reliability of Radial Velocity Mass Estimates of the V1298 Tau Planets

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    Mass, radius, and age measurements of young (<100 Myr) planets have the power to shape our understanding of planet formation. However, young stars tend to be extremely variable in both photometry and radial velocity, which makes constraining these properties challenging. The V1298 Tau system of four ~0.5 Rjup planets transiting a pre-main sequence star presents an important, if stress-inducing, opportunity to directly observe and measure the properties of infant planets. Su\'arez-Mascare\~no et al. (2021) published radial-velocity-derived masses for two of the V1298 Tau planets using a state-of-the-art Gaussian Process regression framework. The planetary densities computed from these masses were surprisingly high, implying extremely rapid contraction after formation in tension with most existing planet formation theories. In an effort to further constrain the masses of the V1298 Tau planets, we obtained 36 RVs using Keck/HIRES, and analyzed them in concert with published RVs and photometry. Through performing a suite of cross validation tests, we found evidence that the preferred model of SM21 suffers from overfitting, defined as the inability to predict unseen data, rendering the masses unreliable. We detail several potential causes of this overfitting, many of which may be important for other RV analyses of other active stars, and recommend that additional time and resources be allocated to understanding and mitigating activity in active young stars such as V1298 Tau.Comment: 26 pages, 12 figures; published in A

    Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

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    The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure
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