114 research outputs found
Prognostic Variables and Surgical Management of Foot Melanoma: Review of a 25-Year Institutional Experience
Introduction. Cutaneous foot melanoma is rare, challenging to manage, and not adequately examined in the literature. This study evaluated the prognostic variables and surgical management of foot melanoma.Materials and Methods. Foot melanoma cases managed at an academic center from 1985 to 2010 were retrospectively reviewed. Results. 46 patients were identified with a broad range of demographic characteristics. Overall recurrence was 32.6%: 19% acral lentiginous, 57% nodular, 66% superficial spreading, 30% melanoma unspecified, 50% severely atypical; 53% ulcerated, 23% nonulcerated; 29% on the dorsum of the foot, 17% heel, 60% ankle, 22% toe, 50% plantar; 0% \u3c1 mm thick, 47% 1–4 mm, 33% \u3e4 mm. 13 had positive nodes, 4 (31%) of whom recurred. Prognostic factors and recurrence did not correlate, and survival was 96% with a median followup of 91 months. Conclusions. Aggressive management of foot melanoma may result in excellent long-term survival even following disease recurrence
A joint model for the emission and absorption properties of damped Lyman alpha absorption systems
The recently discovered population of ultra-faint extended line emitters can
account for the majority of the incidence rate of Damped Lyman Alpha systems
(DLAs) at z ~ 3 if the line emission is interpreted as Ly alpha. We show here
that a model similar to that proposed by Haehnelt, Steinmetz, & Rauch (2000),
which explains the incidence rate and kinematics of DLAs in the context of
CDM models for structure formation, also reproduces the size
distribution of the new population of faint Ly alpha emitters for plausible
parameters. This lends further support to identification of the emitters with
the hitherto elusive population of DLA host galaxies. The observed incidence
rate of DLAs together with the observed space density and size distribution of
the emitters suggest a duty cycle of ~ 0.2 - 0.4 for the Ly alpha emission from
DLA host galaxies. We further show that Ly alpha cooling is expected to
contribute little to the Ly alpha emission for the majority of emitters. This
leaves centrally concentrated star formation at a rate of a few tenths
M_sun/yr, surrounded by extended Ly alpha halos with radii up to 30-50 kpc, as
the most plausible explanation for the origin of the emission. Both the
luminosity function of Ly alpha emission and the velocity width distribution of
low ionization absorption require that galaxies inside Dark Matter (DM) halos
with virial velocities < 50 - 70 km/s contribute little to the incidence rate
of DLAs at z ~ 3, suggesting that energy and momentum input due to star
formation efficiently removes gas from these halos. Galaxies with DM halos with
virial velocities of 100 - 150 km/s appear to account for the majority of DLA
host galaxies. DLA host galaxies at z ~ 3 should thus become the building
blocks of typical present-day galaxies.Comment: 9 Pages, 4 Figures. Submitted to MNRA
DVT Surveillance Program in the ICU: Analysis of Cost-Effectiveness
Background
Venous Thrombo-embolism (VTE – Deep venous thrombosis (DVT) and/or pulmonary embolism (PE) – in traumatized patients causes significant morbidity and mortality. The current study evaluates the effectiveness of DVT surveillance in reducing PE, and performs a cost-effectiveness analysis. Methods
All traumatized patients admitted to the adult ICU underwent twice weekly DVT surveillance by bilateral lower extremity venous Duplex examination (48-month surveillance period – SP). The rates of DVT and PE were recorded and compared to the rates observed in the 36-month pre-surveillance period (PSP). All patients in both periods received mechanical and pharmacologic prophylaxis unless contraindicated. Total costs – diagnostic, therapeutic and surveillance – for both periods were recorded and the incremental cost for each Quality Adjusted Life Year (QALY) gained was calculated. Results
4234 patients were eligible (PSP – 1422 and SP – 2812). Rate of DVT in SP (2.8%) was significantly higher than in PSP (1.3%) – p Conclusions
Surveillance of traumatized ICU patients increases DVT detection and reduces PE incidence. Costs in terms of QALY gained compares favorably with other interventions accepted by society
Faint extended Lyalpha emission due to star formation at the centre of high-column density QSO absorption systems
We use detailed Lyalpha radiative transfer calculations to further test the
claim of Rauch et al. (2008) that they have detected spatially extended faint
Lyalpha emission from the elusive host population of Damped Lyalpha Absorption
systems (DLAs) in their recent ultra-deep spectroscopic survey. We investigate
the spatial and spectral distribution of Lyalpha emission due to star-formation
at the centre of DLAs, and its dependence on the spatial and velocity structure
of the gas. Our model simultaneously reproduces the observed properties of DLAs
and the faint Lyalpha emitters, including the velocity width and column density
distribution of DLAs and the large spatial extent of the emission of the faint
emitters. Our modelling confirms previous suggestions that DLAs are
predominately hosted by Dark Matter (DM) halos in the mass range
10^{9.5}-10^{12} M_sun, and are thus of significantly lower mass than those
inferred for L_* Lyman Break Galaxies (LBGs). Our modelling suggests that DM
halos hosting DLAs retain up to 20% of the cosmic baryon fraction in the form
of neutral hydrogen, and that star formation at the centre of the halos is
responsible for the faint Lyalpha emission. The scattering of a significant
fraction of the Lyalpha emission to the observed radii, which can be as large
as 50 kpc or more, requires the amplitude of the bulk motions of the gas at the
centre of the halos to be moderate. The observed space density and size
distribution of the emitters together with the incidence rate of DLAs suggests
that the Lyalpha emission due to star formation has a duty cycle of ~ 25%.Comment: 17 pages, 13 figures, Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Astroparticle Physics with a Customized Low-Background Broad Energy Germanium Detector
The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg
array of high purity germanium detectors housed in an ultra-low background
shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA
DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while
demonstrating the feasibility of a tonne-scale experiment. It may also carry
out a dark matter search in the 1-10 GeV/c^2 mass range. We have found that
customized Broad Energy Germanium (BEGe) detectors produced by Canberra have
several desirable features for a neutrinoless double-beta decay experiment,
including low electronic noise, excellent pulse shape analysis capabilities,
and simple fabrication. We have deployed a customized BEGe, the MAJORANA
Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and
shield at the Kimballton Underground Research Facility in Virginia. This paper
will focus on the detector characteristics and measurements that can be
performed with such a radiation detector in a low-background environment.Comment: Submitted to NIMA Proceedings, SORMA XII. 9 pages, 4 figure
Becoming Physically Active After Bariatric Surgery is Associated With Improved Weight Loss and Health-Related Quality of Life
The purpose of this study was to determine whether pre- to postoperative increases in physical activity (PA) are associated with weight loss and health-related quality of life (HRQoL) following bariatric surgery. Participants were 199 Roux-en-Y gastric bypass (RYGB) surgery patients. The International Physical Activity Questionnaire (IPAQ) was used to categorize participants into three groups according to their preoperative and /1-year postoperative PA level: (i) Inactive/Active (\u3c200-min/week/≥200-min/week), (ii) Active/Active (≥200-min/week/greater ≥200-min/week) and (iii) Inactive/Inactive (\u3c200-min/week/\u3c200-min/week). The Medical Outcomes Study Short Form-36 (SF-36) was used to assess HRQoL. Analyses of covariance were conducted to examine the effects of PA group on weight and HRQoL changes. Inactive/Active participants, compared with Inactive/Inactive individuals, had greater reductions in weight (52.5 ± 15.4 vs. 46.4 ± 12.8 kg) and BMI (18.9 ± 4.6 vs. 16.9 ± 4.2 kg/m2). Weight loss outcomes in the Inactive/Active and Active/Active groups were similar to each other. Inactive/Active and Active/Active participants reported greater improvements than Inactive/Inactive participants on the mental component summary (MCS) score and the general health, vitality and mental health domains (P \u3c 0.01). Although the direction of causation is not clear, these findings suggest that RYGB patients who become active postoperatively achieve weight losses and HRQoL improvements that are greater than those experienced by patients who remain inactive and comparable to those attained by patients who stay active. Future randomized controlled trials should examine whether assisting patients who are inactive preoperatively to increase their PA postoperatively contributes to optimization of weight loss and HRQoL outcomes
Galactic Winds and Extended Lya Emission from the Host Galaxies of High Column Density QSO Absorption Systems
We present 3D resonant radiative transfer simulations of the spatial and
spectral diffusion of the Lya radiation from a central source in the host
galaxies of high column density absorption systems at z ~ 3. The radiative
transfer simulations are based on a suite of cosmological galaxy formation
simulations that reproduce a wide range of observed properties of damped Lya
absorption systems. The Lya emission is predicted to be spatially extended up
to several arcsec, and the spectral width of the Lya emission is broadened to
several hundred (in some case more than thousand) km/s. The distribution and
the dynamical state of the gas in the simulated galaxies is complex, the latter
with significant contributions from rotation and both in- and out-flows. The
emerging Lya radiation extends to gas with column densities of N_HI ~ 10^{18}
cm^{-2} and its spectral shape varies strongly with viewing angle. The strong
dependence on the central \hi column density and the HI velocity field suggests
that the Lya emission will also vary strongly with time on timescales of a few
dynamical times of the central region. Such variations with time should be
especially pronounced at times where the host galaxy undergoes a major merger
and/or starburst. Depending on the pre-dominance of in- or out-flow along a
given sightline and the central column density, the spectra show prominent blue
peaks, red peaks or double-peaked profiles. Both spatial distribution and
spectral shape are very sensitive to details of the galactic wind
implementation. Stronger galactic winds result in more spatially extended Lya
emission and - somewhat counterintuitively - a narrower spectral distribution.Comment: 16 pages, 9 figures. Submitted to MNRAS on 20th Dec, 201
The DOE E3SM Coupled Model Version 1: Overview and Evaluation at Standard Resolution
This work documents the first version of the U.S. Department of Energy (DOE) new Energy Exascale Earth System Model (E3SMv1). We focus on the standard resolution of the fully coupled physical model designed to address DOE mission-relevant water cycle questions. Its components include atmosphere and land (110-km grid spacing), ocean and sea ice (60 km in the midlatitudes and 30 km at the equator and poles), and river transport (55 km) models. This base configuration will also serve as a foundation for additional configurations exploring higher horizontal resolution as well as augmented capabilities in the form of biogeochemistry and cryosphere configurations. The performance of E3SMv1 is evaluated by means of a standard set of Coupled Model Intercomparison Project Phase 6 (CMIP6) Diagnosis, Evaluation, and Characterization of Klima simulations consisting of a long preindustrial control, historical simulations (ensembles of fully coupled and prescribed SSTs) as well as idealized CO2 forcing simulations. The model performs well overall with biases typical of other CMIP-class models, although the simulated Atlantic Meridional Overturning Circulation is weaker than many CMIP-class models. While the E3SMv1 historical ensemble captures the bulk of the observed warming between preindustrial (1850) and present day, the trajectory of the warming diverges from observations in the second half of the twentieth century with a period of delayed warming followed by an excessive warming trend. Using a two-layer energy balance model, we attribute this divergence to the model’s strong aerosol-related effective radiative forcing (ERFari+aci = -1.65 W/m2) and high equilibrium climate sensitivity (ECS = 5.3 K).Plain Language SummaryThe U.S. Department of Energy funded the development of a new state-of-the-art Earth system model for research and applications relevant to its mission. The Energy Exascale Earth System Model version 1 (E3SMv1) consists of five interacting components for the global atmosphere, land surface, ocean, sea ice, and rivers. Three of these components (ocean, sea ice, and river) are new and have not been coupled into an Earth system model previously. The atmosphere and land surface components were created by extending existing components part of the Community Earth System Model, Version 1. E3SMv1’s capabilities are demonstrated by performing a set of standardized simulation experiments described by the Coupled Model Intercomparison Project Phase 6 (CMIP6) Diagnosis, Evaluation, and Characterization of Klima protocol at standard horizontal spatial resolution of approximately 1° latitude and longitude. The model reproduces global and regional climate features well compared to observations. Simulated warming between 1850 and 2015 matches observations, but the model is too cold by about 0.5 °C between 1960 and 1990 and later warms at a rate greater than observed. A thermodynamic analysis of the model’s response to greenhouse gas and aerosol radiative affects may explain the reasons for the discrepancy.Key PointsThis work documents E3SMv1, the first version of the U.S. DOE Energy Exascale Earth System ModelThe performance of E3SMv1 is documented with a set of standard CMIP6 DECK and historical simulations comprising nearly 3,000 yearsE3SMv1 has a high equilibrium climate sensitivity (5.3 K) and strong aerosol-related effective radiative forcing (-1.65 W/m2)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151288/1/jame20860_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151288/2/jame20860.pd
American Gut: an Open Platform for Citizen Science Microbiome Research
McDonald D, Hyde E, Debelius JW, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18
QCD and strongly coupled gauge theories : challenges and perspectives
We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe
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