1,617 research outputs found

    Student Wellness and the Residency Experience

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    This project surveys MS Mental Health/Marriage Couple and Family /Career residency students. Data has been collected over the course of one year of residencies in a variety of geographic locations to determine students’ perceptions of how the Walden University residency experience impacts personal wellness. Preliminary results will be reported. The goal is to use the information to assist Walden faculty in the training, education, and personal support of counseling students in their professional and personal growth and development.https://scholarworks.waldenu.edu/archivedposters/1020/thumbnail.jp

    Student Wellness and the Residency Experience

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    This project surveys MS Mental Health/Marriage Couple and Family /Career residency students. Data has been collected over the course of one year of residencies in a variety of geographic locations to determine students’ perceptions of how the Walden University residency experience impacts personal wellness. Preliminary results will be reported. The goal is to use the information to assist Walden faculty in the training, education, and personal support of counseling students in their professional and personal growth and development.https://scholarworks.waldenu.edu/archivedposters/1020/thumbnail.jp

    QED blue-sheet effects inside black holes

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    The interaction of the unboundedly blue-shifted photons of the cosmic microwave background radiation with a physical object falling towards the inner horizon of a Reissner-Nordstrom black hole is analyzed. To evaluate this interaction we consider the QED effects up to the second order in the perturbation expansion. We then extrapolate the QED effects up to a cutoff, which we introduce at the Planckian level. (Our results are not sensitive to the cutoff energy.) We find that the energy absorbed by an infalling observer is finite, and for typical parameters would not lead to a catastrophic heating. However, this interaction would almost certainly be fatal for a human being, or other living organism of similar size. On the other hand, we find that smaller objects may survive the interaction. Our results do not provide support to the idea that the Cauchy horizon is to be regarded as the boundary of spacetime.Comment: 6 pages, LaTeX. To appear in Phys. Rev.

    The Nature of LINERs

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    We present JJ-band (1.151.35μ1.15-1.35 \mum) spectroscopy of a sample of nine galaxies showing some degree of LINER activity (classical LINERs, weak-[O {\sc i}] LINERs and transition objects), together with HH-band spectroscopy for some of them. A careful subtraction of the stellar continuum allows us to obtain reliable [Fe {\sc ii}]1.2567μ1.2567 \mum/Paβ\beta line ratios. We conclude that different types of LINERs (i.e., photoionized by a stellar continuum or by an AGN) cannot be easily distinguished based solely on the [Fe {\sc ii}]1.2567μ1.2567 \mum/Paβ\beta line ratio. The emission line properties of many LINERs can be explained in terms of an aging starburst. The optical line ratios of these LINERs are reproduced by a model with a metal-rich H {\sc ii} region component photoionized with a single stellar temperature T=38,000T_* = 38,000 K, plus a supernova remnant (SNR) component. The [Fe {\sc ii}] line is predominantly excited by shocks produced by SNRs in starbursts and starburst-dominated LINERs, while Paβ\beta tracks H {\sc ii} regions ionized by massive young stars. The contribution from SNRs to the overall emission line spectrum is constrained by the [Fe {\sc ii}]1.2567μ1.2567 \mum/Paβ\beta line ratio. Although our models for aging starbursts are constrained only by these infrared lines, they consistently explain the optical spectra of the galaxies also. The LINER-starburst connection is tested by predicting the time dependence of the ratio of the ionizing luminosity (LionL_{\rm ion}) to the supernova rate (SNr), LionL_{\rm ion}/(SNr). We predict the relative number of starbursts to starburst-dominated LINERs (aging starbursts) and show that it is in approximate agreement with survey findings for nearby galaxies.Comment: Accepted in ApJ (19 pages, 8 figures, uses emulateapj.sty

    Planet Hunters VII. Discovery of a New Low-Mass, Low-Density Planet (PH3 c) Orbiting Kepler-289 with Mass Measurements of Two Additional Planets (PH3 b and d)

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    We report the discovery of one newly confirmed planet (P=66.06P=66.06 days, RP=2.68±0.17RR_{\rm{P}}=2.68\pm0.17R_\oplus) and mass determinations of two previously validated Kepler planets, Kepler-289 b (P=34.55P=34.55 days, RP=2.15±0.10RR_{\rm{P}}=2.15\pm0.10R_\oplus) and Kepler-289-c (P=125.85P=125.85 days, RP=11.59±0.10RR_{\rm{P}}=11.59\pm0.10R_\oplus), through their transit timing variations (TTVs). We also exclude the possibility that these three planets reside in a 1:2:41:2:4 Laplace resonance. The outer planet has very deep (1.3\sim1.3%), high signal-to-noise transits, which puts extremely tight constraints on its host star's stellar properties via Kepler's Third Law. The star PH3 is a young (1\sim1 Gyr as determined by isochrones and gyrochronology), Sun-like star with M=1.08±0.02MM_*=1.08\pm0.02M_\odot, R=1.00±0.02RR_*=1.00\pm0.02R_\odot, and Teff=5990±38T_{\rm{eff}}=5990\pm38 K. The middle planet's large TTV amplitude (5\sim5 hours) resulted either in non-detections or inaccurate detections in previous searches. A strong chopping signal, a shorter period sinusoid in the TTVs, allows us to break the mass-eccentricity degeneracy and uniquely determine the masses of the inner, middle, and outer planets to be M=7.3±6.8MM=7.3\pm6.8M_\oplus, 4.0±0.9M4.0\pm0.9M_\oplus, and M=132±17MM=132\pm17M_\oplus, which we designate PH3 b, c, and d, respectively. Furthermore, the middle planet, PH3 c, has a relatively low density, ρ=1.2±0.3\rho=1.2\pm0.3 g/cm3^3 for a planet of its mass, requiring a substantial H/He atmosphere of 2.10.3+0.82.1^{+0.8}_{-0.3}% by mass, and joins a growing population of low-mass, low-density planets.Comment: 21 pages, 10 figures, 5 tables, accepted into Ap

    Recurrent adult-onset hypophyseal Langerhans cell histiocytosis after radiotherapy: A case report

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    INTRODUCTION: Langerhans cell histiocytosis is a rare disease within the adult population, with very few cases reported as solitary hypophyseal lesions in adults. Of the reported cases, most have been treated successfully with surgery, radiotherapy, and/or chemotherapy. Radiotherapy has been thought to be curative at the relatively low dose of 20Gy. Here we report a case of recurrent hypophyseal Langerhans cell histiocytosis 9 months after radiotherapy with an interval period of symptomatic and radiographic response to therapy. CASE PRESENTATION: A 50-year-old Caucasian woman who had headaches, memory difficulties, and diabetes insipidus was found to have a 2.5cm suprasellar mass. Langerhans cell histiocytosis was diagnosed following stereotactic brain biopsy. Further workup revealed no other lesions. Initial radiation treatment succeeded in shrinking the tumor and relieving clinical symptoms temporarily; however, growth and recurrence of clinical symptoms was noted at 9 months. Re-irradiation was well tolerated and the patient had no acute side effects. CONCLUSION: Isolated hypophyseal involvement by Langerhans cell histiocytosis in adults is a unique presentation of a rare disease. Although radiotherapy doses as low as 20Gy have been reported to offer control, this case demonstrates that higher doses may be warranted to ensure tumor control. With modern imaging and radiotherapy techniques higher doses should offer little increased more durable risk to surrounding critical structures

    Planet Hunters. V. A Confirmed Jupiter-Size Planet in the Habitable Zone and 42 Planet Candidates from the Kepler Archive Data

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    We report the latest Planet Hunter results, including PH2 b, a Jupiter-size (R_PL = 10.12 \pm 0.56 R_E) planet orbiting in the habitable zone of a solar-type star. PH2 b was elevated from candidate status when a series of false positive tests yielded a 99.9% confidence level that transit events detected around the star KIC 12735740 had a planetary origin. Planet Hunter volunteers have also discovered 42 new planet candidates in the Kepler public archive data, of which 33 have at least three transits recorded. Most of these transit candidates have orbital periods longer than 100 days and 20 are potentially located in the habitable zones of their host stars. Nine candidates were detected with only two transit events and the prospective periods are longer than 400 days. The photometric models suggest that these objects have radii that range between Neptune to Jupiter. These detections nearly double the number of gas giant planet candidates orbiting at habitable zone distances. We conducted spectroscopic observations for nine of the brighter targets to improve the stellar parameters and we obtained adaptive optics imaging for four of the stars to search for blended background or foreground stars that could confuse our photometric modeling. We present an iterative analysis method to derive the stellar and planet properties and uncertainties by combining the available spectroscopic parameters, stellar evolution models, and transiting light curve parameters, weighted by the measurement errors. Planet Hunters is a citizen science project that crowd-sources the assessment of NASA Kepler light curves. The discovery of these 43 planet candidates demonstrates the success of citizen scientists at identifying planet candidates, even in longer period orbits with only two or three transit events.Comment: 35 pages, 11 figures, 6 tables, accepted and published on ApJ ApJ, 776, 1

    A retrospective analysis of survival and prognostic factors after stereotactic radiosurgery for aggressive meningiomas

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    BACKGROUND: While most meningiomas are benign, aggressive meningiomas are associated with high levels of recurrence and mortality. A single institution’s Gamma Knife radiosurgical experience with atypical and malignant meningiomas is presented, stratified by the most recent WHO classification. METHODS: Thirty-one patients with atypical and 4 patients with malignant meningiomas treated with Gamma Knife radiosurgery between July 2000 and July 2011 were retrospectively reviewed. All patients underwent prior surgical resection. Overall survival was the primary endpoint and rate of disease recurrence in the brain was a secondary endpoint. Patients who had previous radiotherapy or prior surgical resection were included. Kaplan-Meier and Cox proportional hazards models were used to estimate survival and identify factors predictive of recurrence and survival. RESULTS: Post-Gamma Knife recurrence was identified in 11 patients (31.4%) with a median overall survival of 36 months and progression-free survival of 25.8 months. Nine patients (25.7%) had died. Three-year overall survival (OS) and progression-free survival (PFS) rates were 78.0% and 65.0%, respectively. WHO grade II 3-year OS and PFS were 83.4% and 70.1%, while WHO grade III 3-year OS and PFS were 33.3% and 0%. Recurrence rate was significantly higher in patients with a prior history of benign meningioma, nuclear atypia, high mitotic rate, spontaneous necrosis, and WHO grade III diagnosis on univariate analysis; only WHO grade III diagnosis was significant on multivariate analysis. Overall survival was adversely affected in patients with WHO grade III diagnosis, prior history of benign meningioma, prior fractionated radiotherapy, larger tumor volume, and higher isocenter number on univariate analysis; WHO grade III diagnosis and larger treated tumor volume were significant on multivariate analysis. CONCLUSION: Atypical and anaplastic meningiomas remain difficult tumors to treat. WHO grade III diagnosis and treated tumor volume were significantly predictive of recurrence and survival on multivariate analysis in aggressive meningioma patients treated with radiosurgery. Larger tumor size predicts poor survival, while nuclear atypia, necrosis, and increased mitotic rate are risk factors for recurrence. Clinical and pathologic predictors may help identify patients that are at higher risk for recurrence

    Stratospheric Response in the First Geoengineering Simulation Meeting Multiple Surface Climate Objectives

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    We describe here changes in stratospheric dynamics and chemistry in a first century‐long sulfate aerosol geoengineering simulation in which the mean surface temperature and the interhemispheric and equator‐to‐pole surface temperature gradients were kept near their 2020 levels despite the RCP8.5 emission scenario. Simulations were carried out with the Community Earth System Model, version 1 with the Whole Atmosphere Community Climate Model as its atmospheric component [CESM1(WACCM)] coupled to a feedback algorithm controlling the magnitude of sulfur dioxide (SO_2) injections at four injection latitudes. We find that, throughout the entire geoengineering simulation, the lower stratospheric temperatures increase by ∼0.19 K per Tg SO_2 injection per year or ∼10 K with ∼40 Tg SO_2/year total SO_2 injection. These temperature changes are associated with a strengthening of the polar jets in the stratosphere and weakening of the mean zonal wind in the lower stratosphere subtropics and throughout the troposphere, associated with weaker storm track activity. In the geoengineering simulation the quasi‐biennial oscillation of the tropical lower stratospheric winds remains close to the presently observed quasi‐biennial oscillation, even for large amounts of SO2 injection. Water vapor in the stratosphere increases substantially: by 25% with ∼20 Tg SO_2/year annual injection and by up to 90% with a ∼40 Tg SO_2/year injection. Stratospheric column ozone in the geoengineering simulation is predicted to recover to or supersede preozone hole conditions by the end of the century

    Hyaluronidase Hyal1 Increases Tumor Cell Proliferation and Motility through Accelerated Vesicle Trafficking

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    Background: Hyal1 is a turnover enzyme for hyaluronan that accelerates metastatic cancer by increasing cell motility. Results: Hyal1-overexpressing cells have a higher rate of endocytosis that impacts cargo internalization and recycling. Conclusion: The higher rate of vesicle trafficking increases motility receptor function and nutrient uptake. Significance: This novel mechanism implicates Hyal1 trafficking in multiple signaling events during tumor progression
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