2,901 research outputs found

    Deep, Wide-field CCD Photometry for the Open Cluster NGC3532

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    We present the results of a deep, wide-field CCD survey for the open cluster NGC~3532. Our new BV(RI)cBV(RI)_{c} photometry effectively covers a one square degree area and reaches an unprecedented depth of V21V\sim21 to reveal that NGC~3532 is a rich open cluster that harbors a large number of faint, low-mass stars. We employ a number of methods to reduce the impact of field star contamination in the cluster color-magnitude diagrams, including supplementing our photometry with JHKsJHK_{s} data from the 2MASS catalog. These efforts allow us to define a robust sample of candidate main sequence stars suitable for a purely empirical determination of the cluster's parameters by comparing them to the well-established Hyades main sequence. Our results confirm previous findings that NGC~3532 lies fairly near to the Sun [(mM)0=8.46±0.05(m-M)_0=8.46\pm0.05; 49211+12492^{+12}_{-11}~pc] and has an extremely low reddening for its location near the Galactic plane [E(BV)=0.028±0.006E(B-V)=0.028\pm0.006]. Moreover, an age of 300\sim300\,Myr has been derived for the cluster by fitting a set of overshooting isochrones to the well-populated upper main-sequence. This new photometry also extends faint enough to reach the cluster white dwarf sequence, as confirmed by our photometric recovery of eight spectroscopically identified members of the cluster. Using the location of these eight members, along with the latest theoretical cooling tracks, we have identified 30\sim30 additional white dwarf stars in the [V, (BV)][V,~(B-V)] color-magnitude diagram that have a high probability of belonging to NGC~3532. The age we derive from fitting white dwarf isochrones to the locus of these stars, 300±100300\pm100\,Myr, is consistent with the age derived from the turnoff. Our analysis of the photometry also includes an estimation of the binary star fraction, as well as a determination of the cluster's luminosity and mass functions.Comment: Accepted for publication in AJ. 55 pages, 21 figures. High-quality version with complete data tables can be downloaded from http://www.phys.lsu.edu/~jclem/NGC3532

    Helsinki Stroke Model Is Transferrable With "Real-World" Resources and Reduced Stroke Thrombolysis Delay to 34 min in Christchurch

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    Background: Christchurch hospital is a tertiary hospital in New Zealand supported by five general neurologists with after-hours services provided mainly by onsite non-neurology medical residents. We assessed the transferrability and impact of the Helsinki Stroke model on stroke thrombolysis door-to-needle time (DNT) in Christchurch hospital. Methods: Key components of the Helsinki Stroke model were implemented first in 2015 with introduction of patient pre-notification and thrombolysis by the computed tomography (CT) suite, followed by implementation of direct transfer to CT on ambulance stretcher in May 2017. Data from the prospective thrombolysis registry which began in 2012 were analyzed for the impact of these interventions on median DNT. Results: Between May and December 2017, 46 patients were treated with alteplase, 25 (54%) patients were treated in-hours (08:00-17:00 non-public holiday weekdays) and 21 (46%) patients were treated after-hours. The in-hours, after-hours, and overall median (interquartile range) DNTs were 34 (28-43), 47 (38-60), and 40 (30-51) minutes. The corresponding times in 2012-2014 prior to interventions were 87 (68-106), 86 (72-116), and 87 (71-112) minutes, representing median DNT reduction of 53, 39, and 47 minutes, respectively (p-values <0.01). The interventions also resulted in significant reductions in the overall median door-to-CT time (from 49 to 19 min), CT-to-needle time (32 to 20 min) and onset-to-needle time (168 to 120 min). Conclusion: The Helsinki stroke model is transferrable with real-world resources and reduced stroke DNT in Christchurch by over 50%.Peer reviewe

    The Vaginal Microbiome: Disease, Genetics and the Environment

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    The vagina is an interactive interface between the host and the environment. Its surface is covered by a protective epithelium colonized by bacteria and other microorganisms. The ectocervix is nonsterile, whereas the endocervix and the upper genital tract are assumed to be sterile in healthy women. Therefore, the cervix serves a pivotal role as a gatekeeper to protect the upper genital tract from microbial invasion and subsequent reproductive pathology. Microorganisms that cross this barrier can cause preterm labor, pelvic inflammatory disease, and other gynecologic and reproductive disorders. Homeostasis of the microbiome in the vagina and ectocervix plays a paramount role in reproductive health. Depending on its composition, the microbiome may protect the vagina from infectious or non-infectious diseases, or it may enhance its susceptibility to them. Because of the nature of this organ, and the fact that it is continuously colonized by bacteria from birth to death, it is virtually certain that this rich environment evolved in concert with its microbial flora. Specific interactions dictated by the genetics of both the host and microbes are likely responsible for maintaining both the environment and the microbiome. However, the genetic basis of these interactions in both the host and the bacterial colonizers is currently unknown. _Lactobacillus_ species are associated with vaginal health, but the role of these species in the maintenance of health is not yet well defined. Similarly, other species, including those representing minor components of the overall flora, undoubtedly influence the ability of potential pathogens to thrive and cause disease. Gross alterations in the vaginal microbiome are frequently observed in women with bacterial vaginosis, but the exact etiology of this disorder is still unknown. There are also implications for vaginal flora in non-infectious conditions such as pregnancy, pre-term labor and birth, and possibly fertility and other aspects of women&#x2019;s health. Conversely, the role of environmental factors in the maintenance of a healthy vaginal microbiome is largely unknown. To explore these issues, we have proposed to address the following questions:&#xd;&#xa;&#xd;&#xa;*1.&#x9;Do the genes of the host contribute to the composition of the vaginal microbiome?* We hypothesize that genes of both host and bacteria have important impacts on the vaginal microbiome. We are addressing this question by examining the vaginal microbiomes of mono- and dizygotic twin pairs selected from the over 170,000 twin pairs in the Mid-Atlantic Twin Registry (MATR). Subsequent studies, beyond the scope of the current project, may investigate which host genes impact the microbial flora and how they do so.&#xd;&#xa;*2.&#x9;What changes in the microbiome are associated with common non-infectious pathological states of the host?* We hypothesize that altered physiological (e.g., pregnancy) and pathologic (e.g., immune suppression) conditions, or environmental exposures (e.g., antibiotics) predictably alter the vaginal microbiome. Conversely, certain vaginal microbiome characteristics are thought to contribute to a woman&#x2019;s risk for outcomes such as preterm delivery. We are addressing this question by recruiting study participants from the ~40,000 annual clinical visits to women&#x2019;s clinics of the VCU Health System.&#xd;&#xa;*3.&#x9;What changes in the vaginal microbiome are associated with relevant infectious diseases and conditions?* We hypothesize that susceptibility to infectious disease (e.g. HPV, _Chlamydia_ infection, vaginitis, vaginosis, etc.) is impacted by the vaginal microbiome. In turn, these infectious conditions clearly can affect the ability of other bacteria to colonize and cause pathology. Again, we are exploring these issues by recruiting participants from visitors to women&#x2019;s clinics in the VCU Health System.&#xd;&#xa;&#xd;&#xa;Three kinds of sequence data are generated in this project: i) rDNA sequences from vaginal microbes; ii) whole metagenome shotgun sequences from vaginal samples; and iii) whole genome shotgun sequences of bacterial clones selected from vaginal samples. The study includes samples from three vaginal sites: mid-vaginal, cervical, and introital. The data sets also include buccal and perianal samples from all twin participants. Samples from these additional sites are used to test the hypothesis of a per continuum spread of bacteria in relation to vaginal health. An extended set of clinical metadata associated with these sequences are deposited with dbGAP. We have currently collected over 4,400 samples from ~100 twins and over 450 clinical participants. We have analyzed and deposited data for 480 rDNA samples, eight whole metagenome shotgun samples, and over 50 complete bacterial genomes. These data are available to accredited investigators according to NIH and Human Microbiome Project (HMP) guidelines. The bacterial clones are deposited in the Biodefense and Emerging Infections Research Resources Repository (&#x22;http://www.beiresources.org/&#x22;:http://www.beiresources.org/). &#xd;&#xa;&#xd;&#xa;In addition to the extensive sequence data obtained in this study, we are collecting metadata associated with each of the study participants. Thus, participants are asked to complete an extensive health history questionnaire at the time samples are collected. Selected clinical data associated with the visit are also obtained, and relevant information is collected from the medical records when available. This data is maintained securely in a HIPAA-compliant data system as required by VCU&#x2019;s Institutional Review Board (IRB). The preponderance of these data (i.e., that judged appropriate by NIH staff and VCU&#x2019;s IRB are deposited at dbGAP (&#x22;http://www.ncbi.nlm.nih.gov/gap&#x22;:http://www.ncbi.nlm.nih.gov/gap). Selected fields of this data have been identified by NIH staff as &#x2018;too sensitive&#x2019; and are not available in dbGAP. Individuals requiring access to these data fields are asked to contact the PI of this project or NIH Program Staff. &#xd;&#xa

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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