214 research outputs found

    Photometric Monitoring of the Gravitationally Lensed Ultraluminous BAL Quasar APM08279+5255

    Full text link
    We report on one year of photometric monitoring of the ultraluminous BAL quasar APM 08279+5255. The temporal sampling reveals that this gravitationally lensed system has brightened by ~0.2 mag in 100 days. Two potential causes present themselves; either the variability is intrinsic to the quasar, or it is the result of microlensing by stars in a foreground system. The data is consistent with both hypotheses and further monitoring is required before either case can be conclusively confirmed. We demonstrate, however, that gravitational microlensing can not play a dominant role in explaining the phenomenal properties exhibited by APM 08279+5255. The identification of intrinsic variability, coupled with the simple gravitational lensing configuration, would suggest that APM 08279+5255 is a potential golden lens from which the cosmological parameters can be derived and is worthy of a monitoring program at high spatial resolution.Comment: 17 pages, with 2 figures. Accepted for publication in P.A.S.

    Bright Variable Stars in NGC 6819 - An Open Cluster in the Kepler Field

    Full text link
    We describe a variability study of the moderately old open cluster NGC 6819. We have detected 4 new detached eclipsing binaries near the cluster turnoff (one of which may be in a triple system). Several of these systems should be able to provide mass and radius information, and can therefore constrain the age of the cluster. We have also newly detected one possible detached binary member about 3.5 magnitudes below the turnoff. One EW-type binary (probably not a cluster member) shows unusually strong night-to-night light curve variations in sets of observations separated by 8 years. According to the best current information, the three brightest variables we detected (2 of them new) are cluster members, making them blue stragglers. One is a delta Scu pulsating variable, one is a close but detached binary, and the third contains a detached short period binary that shows total eclipses. In each case, however, there is evidence hinting that the system may have been produced through the interaction of more than two stars.Comment: 33 pages, 15 figures, accepted to A

    Efficiency of primary spine care as compared to conventional primary care: a retrospective observational study at an Academic Medical Center

    Get PDF
    Background: Primary Spine Care (PSC) is an innovative model for the primary management of patients with spine-related disorders (SRDs), with a focus on the use of non-pharmacological therapies which now constitute the recommended first-line approach to back pain. PSC clinicians serve as the initial or early point of contact for spine patients and utilize evidence-based spine care pathways to improve outcomes and reduce escalation of care (EoC; e.g., spinal injections, diagnostic imaging, hospitalizations, referrals to a specialist). The present study examined 6-month outcomes to evaluate the efficiency of care for patients who received PSC as compared to conventional primary care. We hypothesized that patients seen by a PSC clinician would have lower rates of EoC compared to patients who received usual care by a primary care (PC) clinician. Methods: This was a retrospective observational study. We evaluated 6-month outcomes for two groups seen and treated for an SRD between February 01, 2017 and January 31, 2020. Patient groups were comprised of N = 1363 PSC patients (Group A) and N = 1329 PC patients (Group B). We conducted Pearson chi-square and logistic regression (adjusting for patient characteristics that were unbalanced between the two groups) to determine associations between the two groups and 6-month outcomes. Results: Within six months of an initial visit for an SRD, a statistically significantly smaller proportion of PSC patients utilized healthcare resources for spine care as compared to the PC patients. When adjusting for patient characteristics, those who received care from the PSC clinician were less likely within 6 months of an initial visit to be hospitalized (OR =.47, 95% CI.23–.97), fill a prescription for an opioid analgesic (OR =.43; 95% CI.29–.65), receive a spinal injection (OR =.56, 95% CI.33–.95), or have a visit with a specialist (OR =.48, 95% CI.35–.67) as compared to those who received usual primary care. Conclusions: Patients who received PSC in an academic primary care clinic experienced significantly less escalation of their spine care within 6 months of their initial visit. The PSC model may offer a more efficient approach to the primary care of spine problems for patients with SRDs, as compared to usual primary care

    V2197 Cyg - A Semi-Detached Eclipsing Binary?

    Get PDF
    The variability of V2197 Cyg (NSVS 5761314, TYC 3167-1279-1), amongst many others, was discovered photographically by Margoni & Stagni (1984, hereafter M&S) who gave coordinates, magnitude ranges in B and V , finder charts for all 99 stars, elements (epoch, period), and preliminary light curves for about half the stars (but not for V2176 Cyg, their #58). Andronov et al. (1993) performed U,B, V,R, and I photometry of this and three other M&S stars; they went on in Andronov et al. (1994) to identify the system as an eclipsing variable, also giving the elements (including period = 0.46771 d) and eclipse duration. Skiff (1997) identified the M&S variables with those in the IRAS and GSC catalogues. Hoffman et al. (2008) provided an updated period, quoted 2MASS colours, and classified the system as \u3b2 Lyrae. Since then, there have been a number of eclipse timings but no light curve analysis.Peer reviewed: YesNRC publication: Ye

    Establishing What Constitutes a Healthy Human Gut Microbiome: State of the Science, Regulatory Considerations, and Future Directions.

    Get PDF
    On December 17, 2018, the North American branch of the International Life Sciences Institute (ILSI North America) convened a workshop "Can We Begin to Define a Healthy Gut Microbiome Through Quantifiable Characteristics?" with >40 invited academic, government, and industry experts in Washington, DC. The workshop objectives were to 1) develop a collective expert assessment of the state of the evidence on the human gut microbiome and associated human health benefits, 2) see if there was sufficient evidence to establish measurable gut microbiome characteristics that could serve as indicators of "health," 3) identify short- and long-term research needs to fully characterize healthy gut microbiome-host relationships, and 4) publish the findings. Conclusions were as follows: 1) mechanistic links of specific changes in gut microbiome structure with function or markers of human health are not yet established; 2) it is not established if dysbiosis is a cause, consequence, or both of changes in human gut epithelial function and disease; 3) microbiome communities are highly individualized, show a high degree of interindividual variation to perturbation, and tend to be stable over years; 4) the complexity of microbiome-host interactions requires a comprehensive, multidisciplinary research agenda to elucidate relationships between gut microbiome and host health; 5) biomarkers and/or surrogate indicators of host function and pathogenic processes based on the microbiome need to be determined and validated, along with normal ranges, using approaches similar to those used to establish biomarkers and/or surrogate indicators based on host metabolic phenotypes; 6) future studies measuring responses to an exposure or intervention need to combine validated microbiome-related biomarkers and/or surrogate indicators with multiomics characterization of the microbiome; and 7) because static genetic sampling misses important short- and long-term microbiome-related dynamic changes to host health, future studies must be powered to account for inter- and intraindividual variation and should use repeated measures within individuals

    Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

    Get PDF
    BACKGROUND: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control. METHODS: Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights. FINDINGS: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease. INTERPRETATION: International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems

    The structure of IL2 bound to the three chains of the IL2 receptor and how signaling occurs

    Get PDF
    The interleukin-2 molecule and receptor were the first of the interleukins to be discovered and characterized at the molecular level. Now after 20 years of effort, two groups have succeeded in determining the structure of IL2 bound to the external domains of the three receptor chains in a quaternary complex. What do we know now that we did not know before this structural information was available, and how do these new data help us to develop new therapies

    Application of Broad-Spectrum, Sequence-Based Pathogen Identification in an Urban Population

    Get PDF
    A broad spectrum detection platform that provides sequence level resolution of target regions would have a significant impact in public health, case management, and means of expanding our understanding of the etiology of diseases. A previously developed respiratory pathogen microarray (RPM v.1) demonstrated the capability of this platform for this purpose. This newly developed RPM v.1 was used to analyze 424 well-characterized nasal wash specimens from patients presenting with febrile respiratory illness in the Washington, D. C. metropolitan region. For each specimen, the RPM v.1 results were compared against composite reference assay (viral and bacterial culture and, where appropriate, RT-PCR/PCR) results. Across this panel, the RPM assay showed ≥98% overall agreement for all the organisms detected compared with reference methods. Additionally, the RPM v.1 results provide sequence information which allowed phylogenetic classification of circulating influenza A viruses in ∼250 clinical specimens, and allowed monitoring the genetic variation as well as antigenic variability prediction. Multiple pathogens (2–4) were detected in 58 specimens (13.7%) with notably increased abundances of respiratory colonizers (esp. S. pneumoniae) during viral infection. This first-ever comparison of a broad-spectrum viral and bacterial identification technology of this type against a large battery of conventional “gold standard” assays confirms the utility of the approach for both medical surveillance and investigations of complex etiologies of illness caused by respiratory co-infections

    Phenotyping male infertility in the mouse: how to get the most out of a ‘non-performer’

    Get PDF
    BACKGROUND: Functional male gametes are produced through complex processes that take place within the testis, epididymis and female reproductive tract. A breakdown at any of these phases can result in male infertility. The production of mutant mouse models often yields an unexpected male infertility phenotype. It is with this in mind that the current review has been written. The review aims to act as a guide to the 'non-reproductive biologist' to facilitate a systematic analysis of sterile or subfertile mice and to assist in extracting the maximum amount of information from each model. METHODS: This is a review of the original literature on defects in the processes that take a mouse spermatogonial stem cell through to a fully functional spermatozoon, which result in male infertility. Based on literature searches and personal experience, we have outlined a step-by-step strategy for the analysis of an infertile male mouse line. RESULTS: A wide range of methods can be used to define the phenotype of an infertile male mouse. These methods range from histological methods such as electron microscopy and immunohistochemistry, to hormone analyses and methods to assess sperm maturation status and functional competence. CONCLUSION: With the increased rate of genetically modified mouse production, the generation of mouse models with unexpected male infertility is increasing. This manuscript will help to ensure that the maximum amount of information is obtained from each mouse model and, by extension, will facilitate the knowledge of both normal fertility processes and the causes of human infertility
    corecore