A Survey for Circumstellar Disks Around Young Substellar Objects

(Abridged) We have completed the first systematic survey for disks around spectroscopically identified young brown dwarfs and very low mass stars. We have obtained L'-band (3.8 um) imaging for 38 very cool objects in IC 348 and Taurus. Our targets span spectral types from M6 to M9.5 (~100 to ~15 Mjup). Using the objects' measured spectral types and extinctions, we find that most of our sample (77%+/-15%) possess intrinsic IR excesses, indicative of disks. Because the excesses are modest, conventional analyses using only IR colors would have missed most of the sources with excesses. The observed IR excesses are correlated with Halpha emission, consistent with a common accretion disk origin. The excesses can be explained by disk reprocessing of starlight alone; the implied accretion rates are at least an order of magnitude below typical values for classical T Tauri stars. The observed distribution of IR excesses suggests the presence of inner disk holes. The disk frequency appears to be independent of the mass and age. In the same star-forming regions, disks around brown dwarfs are at least as long-lived (~3 Myr) as disks around the T Tauri stars. Altogether, the frequency and properties of young circumstellar disks appear to be similar from the stellar regime down to the substellar and planetary-mass regime. This provides prima facie evidence of a common origin for most stars and brown dwarfs.Comment: ApJ, in press, 28 pages. Minor change to the online, abridged version of the abstract. No change to the actual pape

The History, Development and Impact of Computed Imaging in Neurological Diagnosis and Neurosurgery: CT, MRI, and DTI

A steady series of advances in physics, mathematics, computers and clinical imaging science have progressively transformed diagnosis and treatment of neurological and neurosurgical disorders in the 115 years between the discovery of the X-ray and the advent of high resolution diffusion based functional MRI. The story of the progress in human terms, with its battles for priorities, forgotten advances, competing claims, public battles for Nobel Prizes, and patent priority litigations bring alive the human drama of this remarkable collective achievement in computed medical imaging

Size, Internationalization and University Rankings: Evaluating and Predicting Times Higer Education (THE) Data for Japan

International and domestic rankings of academics, academic departments, faculties, schools and colleges, institutions of higher learning, states, regions, and countries are of academic and practical interest and importance to students, parents, academics, and private and public institutions. International and domestic rankings are typically based on arbitrary methodologies and criteria. Evaluating how the rankings might be sensitive to different factors, as well as forecasting how they might change over time, requires a statistical analysis of the factors that affect the rankings. Accurate data on rankings and the associated factors are essential for a valid statistical analysis. In this respect, the Times Higher Education (THE) World University Rankings represent one of the three leading and most influential annual sources of international university rankings. Using recently released data for a single country, namely Japan, the paper evaluates the effects of size (specifically, the number of full-time-equivalent (FTE) students, or FTE (Size)) and internationalization (specifically, the percentage of international students, or IntStud) on academic rankings using THE data for 2017 and 2018 on 258 national, public (that is, prefectural or city), and private universities. The results show that both size and internationalization are statistically significant in explaining rankings for all universities, as well as separately for private and non-private (that is, national and public) universities, in Japan for 2017 and 2018

Size, Internationalization and University Rankings: Evaluating Times Higher Education (THE) Data for Japan

International and domestic rankings of academics, academic departments, faculties, schools and colleges, institutions of higher learning, states, regions and countries, are of academic and practical interest and importance to students, parents, academics, and private and public institutions. International and domestic rankings are typically based on arbitrary methodologies and criteria. Evaluating how the rankings might be sensitive to different factors, as well as forecasting how they might change over time, requires a statistical analysis of the factors that affect the rankings. Accurate data on rankings and the associated factors is essential for a valid statistical analysis. In this respect, the Times Higher Education (THE) World University Rankings is one of the three leading and most influential annual sources of international university rankings. Using recently released data for a single country, namely Japan, the paper evaluates the effects of size (specifically, the number of Full-Time Equivalent (FTE) students, or FTE(Size)) and internationalization (specifically, the percentage of international students, or IntStud) on academic rankings using THE data for 2017 and 2018 on 258 national, public (that is, prefectural or city), and private universities. The results show that both size and internationalization are statistically significant in explaining rankings for all universities, as well as separately for private and non-private (that is, national and public) universities, in Japan for each of 2017 and 2018

Size, Internationalization and University Rankings: Evaluating and Predicting Times Higher Education (THE) Data for Japan

International and domestic rankings of academics, academic departments, faculties, schools and colleges, institutions of higher learning, states, regions and countries, are of academic and practical interest and importance to students, parents, academics, and private and public institutions. International and domestic rankings are typically based on arbitrary methodologies and criteria. Evaluating how the rankings might be sensitive to different factors, as well as forecasting how they might change over time, requires a statistical analysis of the factors that affect the rankings. Accurate data on rankings and the associated factors is essential for a valid statistical analysis. In this respect, the Times Higher Education (THE) World University Rankings is one of the three leading and most influential annual sources of international university rankings. Using recently released data for a single country, namely Japan, the paper evaluates the effects of size (specifically, the number of Full-Time Equivalent (FTE) students, or FTE(Size)) and internationalization (specifically, the percentage of international students, or IntStud) on academic rankings using THE data for 2017 and 2018 on 258 national, public (that is, prefectural or city), and private universities. The results show that both size and internationalization are statistically significant in explaining rankings for all universities, as well as separately for private and non-private (that is, national and public) universities, in Japan for each of 2017 and 201

Incision and abdominal wall hernias in patients with aneurysm or occlusive aortic disease

AbstractIntroductionPatients undergoing midline incision for abdominal aortic reconstruction appear to be at greater risk for postoperative incision hernia compared with patients undergoing celiotomy for general surgical procedures. Controversy exists as to whether incidence of abdominal wall hernia and increased risk for incision hernia is higher in patients with abdominal aortic aneurysm (AAA) than in patients operated on because of aortoiliac occlusive disease (AOD). We conducted a prospective multi-institutional study to assess frequency of incision hernia after aortic surgery through a midline laparotomy and of previous abdominal wall hernia.MethodsPatients with AAA (n = 177) or AOD (n = 82) from three major institutions were prospectively enrolled in the study and examined. Data collected included demographic data, cardiopulmonary risk factors, smoking status, history of previous or current abdominal wall hernia (incision, inguinal, umbilical, femoral), previous midline incision, suture type, and postoperative complications. At a minimum of 6 months after laparotomy, patients were evaluated clinically for a new incision hernia. Differences were tested with the unpaired t test, X2 test, or Fisher exact test, and multiple logistic regression was used to control for confounding variables.ResultsMean follow-up of the cohort was 32.8 ± 2.3 months. Rate of abdominal wall hernia and inguinal hernia in patients with AAA versus AOD was 38.4% versus 11% (P = .001) and 23.7% versus 6.1% (P = .003), respectively. Rate of postoperative incision hernia in patients with AAA was 28.2%, and in patients with AOD was 11.0% (P = .002). Adjusting for age, smoking, chronic obstructive pulmonary disease, body mass index, diabetes, bowel obstruction, and suture type, patients with AAA had almost a ninefold risk for postoperative incision hernia formation (odds ratio [OR], 8.8; P = .0049).ConclusionCompared with patients with AOD, patients with AAA have a higher frequency of abdominal wall hernia and inguinal hernia, and are at significant increased risk for development of incision hernia postoperatively. The higher frequency of hernia formation in patients with AAA suggests the presence of a structural defect within the fascia. Further studies are needed to delineate the molecular changes of the aorta and its relation to the abdominal wall fascia

An Empirical Comparison of Tree-Based Methods for Propensity Score Estimation

To illustrate the use of ensemble tree-based methods (random forest classification [RFC] and bagging) for propensity score estimation and to compare these methods with logistic regression, in the context of evaluating the effect of physical and occupational therapy on preschool motor ability among very low birth weight (VLBW) children

Twenty Thousand-Year-Old Huts at a Hunter-Gatherer Settlement in Eastern Jordan

Ten thousand years before Neolithic farmers settled in permanent villages, hunter-gatherer groups of the Epipalaeolithic period (c. 22–11,600 cal BP) inhabited much of southwest Asia. The latest Epipalaeolithic phase (Natufian) is well-known for the appearance of stone-built houses, complex site organization, a sedentary lifestyle and social complexity—precursors for a Neolithic way of life. In contrast, pre-Natufian sites are much less well known and generally considered as campsites for small groups of seasonally-mobile hunter-gatherers. Work at the Early and Middle Epipalaeolithic aggregation site of Kharaneh IV in eastern Jordan highlights that some of these earlier sites were large aggregation base camps not unlike those of the Natufian and contributes to ongoing debates on their duration of occupation. Here we discuss the excavation of two 20,000-year-old hut structures at Kharaneh IV that pre-date the renowned stone houses of the Natufian. Exceptionally dense and extensive occupational deposits exhibit repeated habitation over prolonged periods, and contain structural remains associated with exotic and potentially symbolic caches of objects (shell, red ochre, and burnt horn cores) that indicate substantial settlement of the site pre-dating the Natufian and outside of the Natufian homeland as currently understood

Enhancing Standard Cardiac Rehabilitation With Stress Management Training: BACKGROUND, METHODS, AND DESIGN FOR THE ENHANCED STUDY

Enhancing Standard Cardiac Rehabilitation with Stress Management Training in Patients with Heart Disease (ENHANCED) is a randomized clinical trial (RCT) funded by the NHLBI to evaluate the effects of stress management training (SMT) on changes in biomarkers of risk and quality of life for patients enrolled in traditional exercise-based cardiac rehabilitation (CR)

Gravity Recovery and Interior Laboratory (GRAIL) Mission: Status at the Initiation of the Science Mapping Phase

The Gravity Recovery And Interior Laboratory (GRAIL) mission, a component of NASA's Discovery Program, launched successfully from Cape Canaveral Air Force Station on September 10, 2011. The dual spacecraft traversed independent, low-energy trajectories to the Moon via the EL-1 Lagrange point and inserted into elliptical, 11.5-hour polar orbits around the Moon on December 31, 2011, and January 1, 2012. The spacecraft are currently executing a series of maneuvers to circularize their orbits at 55-km mean altitude. Once the mapping orbit is achieved, the spacecraft will undergo additional maneuvers to align them into mapping configuration. The mission is on track to initiate the Science Phase on March 8, 2012