344 research outputs found
Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
We substantially update the capabilities of the open source software package
Modules for Experiments in Stellar Astrophysics (MESA), and its one-dimensional
stellar evolution module, MESA Star. Improvements in MESA Star's ability to
model the evolution of giant planets now extends its applicability down to
masses as low as one-tenth that of Jupiter. The dramatic improvement in
asteroseismology enabled by the space-based Kepler and CoRoT missions motivates
our full coupling of the ADIPLS adiabatic pulsation code with MESA Star. This
also motivates a numerical recasting of the Ledoux criterion that is more
easily implemented when many nuclei are present at non-negligible abundances.
This impacts the way in which MESA Star calculates semi-convective and
thermohaline mixing. We exhibit the evolution of 3-8 Msun stars through the end
of core He burning, the onset of He thermal pulses, and arrival on the white
dwarf cooling sequence. We implement diffusion of angular momentum and chemical
abundances that enable calculations of rotating-star models, which we compare
thoroughly with earlier work. We introduce a new treatment of
radiation-dominated envelopes that allows the uninterrupted evolution of
massive stars to core collapse. This enables the generation of new sets of
supernovae, long gamma-ray burst, and pair-instability progenitor models. We
substantially modify the way in which MESA Star solves the fully coupled
stellar structure and composition equations, and we show how this has improved
MESA's performance scaling on multi-core processors. Updates to the modules for
equation of state, opacity, nuclear reaction rates, and atmospheric boundary
conditions are also provided. We describe the MESA Software Development Kit
(SDK) that packages all the required components needed to form a unified and
maintained build environment for MESA. [Abridged]Comment: Accepted for publication in The ApJ Supplement Series. Extra
informations required to reproduce the calculations in this paper are
available at http://mesastar.org/results/mesa
Risk-stratified patients with resectable soft tissue sarcoma benefit from epirubicin-based adjuvant chemotherapy
As adjuvant chemotherapy (AC) for soft tissue sarcomas is controversial, we performed a retrospective analysis of patients seen at Washington University in St. Louis to evaluate whether it benefited our patient population. Patients were risk-assessed using the Memorial Sloan Kettering Predictive Nomogram (MSKPN). We defined high-risk patients by a MSKPN 4-year postoperative probability of sarcoma-specific death of ≥0.3 and investigated if they benefited from AC. Retrospective review was performed on patients seen between 15 February 1996 and 6 February 2010. A propensity score method in the logistic regression framework was used to model the likelihood of receiving AC. To make causal inference on the effect of AC on survival outcomes, a propensity score inverse probability of treatment weighting approach was applied to survival analysis. Overall, 135 high-grade patients were assessed, 33 were treated with Ifosfamide/Epirubicin (I/Epi) and 102 were non AC patients. The stratified MSKPN risk was not significantly associated with any survival endpoint in the whole cohort, but trended for overall survival (OS) when evaluated against non AC patients. After adjustment for MSKPN risk and other variables, patients not receiving chemotherapy had significantly worse OS, recurrent free survival, and disease-specific survival (DSS) with adjusted hazard ratios of 4.18 (95% CI: 2.22–7.90), 8.96 (95% CI: 3.85–20.83), and 5.42 (95% CI: 2.09–14.06), respectively. In retrospective analyses, risk-stratified patients with soft tissue sarcoma benefited from I/Epi-based AC. Randomized I/Epi versus I/Doxorubicin clinical trials may determine the optimal adjuvant treatment
Biomass power plant feedstock procurement: Modeling transportation cost zones and the potential for competition
Transportation of comminuted (processed) woody biomass from the production site to a utilization point is one of the most costly operational components in feedstock procurement. This study identified potential sources of feedstock based on transportation cost from which three woody biomass power plants in Humboldt County, California, could economically obtain their supply. We conducted service area and location-allocation network analyses for timberlands and sawmills, respectively, and created inclusive and exclusive networks to model three transportation cost zones (TCZs). The area within the $20/bone dry ton TCZ had the highest potential supply of woody biomass in the county (709,565 acres). All sawmills in the county were within an economically viable distance of the power plants. Even though there was no competition for raw materials at the time of this study, a competition risk analysis suggested that this could change with shifts in the demand for biomass or the price of electricity. The methods we developed for this study could be adapted to other regions with managed timberlands and a strong forest products industry
Hepatotoxicity following administration of onasemnogene abeparvovec (AVXS-101) for the treatment of spinal muscular atrophy
BACKGROUND & AIMS: Spinal muscular atrophy (SMA) is an autosomal recessive, childhood-onset motor neuron disease. Onasemnogene abeparvovec (OA) is a gene therapy designed to address SMA\u27s root cause. In pivotal mouse toxicology studies, the liver was identified as a major site of OA toxicity. Clinical data reflect elevations in serum aminotransferase concentrations, with some reports of serious acute liver injury. Prophylactic prednisolone mitigates these effects. Herein, we aim to provide pragmatic, supportive guidance for identification, management, and risk mitigation of potential drug-induced liver injury.
METHODS: Data from 325 patients with SMA who had received OA through 31 December 2019, in 5 clinical trials, a managed access program (MAP), and a long-term registry (RESTORE), and through commercial use, were analyzed. Liver-related adverse events, laboratory data, concomitant medications, and prednisolone use were analyzed.
RESULTS: Based on adverse events and laboratory data, 90 of 100 patients had elevated liver function test results (alanine aminotransferase, and/or aspartate aminotransferase, and/or bilirubin concentrations). Of these, liver-associated adverse events were reported for 34 of 100 (34%) and 10 of 43 (23%) patients in clinical trials and MAP/RESTORE, respectively. Two patients in MAP had serious acute liver injury, which resolved completely. While all events in the overall population resolved, prednisolone treatment duration varied (range: 33-229 days), with a majority receiving prednisolone for 60-120 days. More than 60% had elevations in either alanine aminotransferase, aspartate aminotransferase, or bilirubin concentrations prior to dosing. Greater than 40% received potentially hepatotoxic concomitant medications.
CONCLUSIONS: Hepatotoxicity is a known risk associated with OA use. Practitioners should identify contributing factors and mitigate risk through appropriate monitoring and intervention.
LAY SUMMARY: Onasemnogene abeparvovec is a type of medicine called a gene therapy, which is used to treat babies and young children who have a rare, serious inherited condition called spinal muscular atrophy (SMA). It works by supplying a fully functioning copy of the survival motor neuron or SMN gene, which then helps the body produce enough SMN protein. However, it can cause an immune response that could lead to an increase in enzymes produced by the liver. This article provides information about the liver injury and how to prevent and recognize if it happens, so that it may be treated properly
WIYN Open Cluster Study XVI: Optical/Infrared Photometry and Comparisons With Theoretical Isochrones
We present combined optical/near-IR photometry (BVIK) for six open clusters -
M35, M37, NGC 1817, NGC 2477, NGC 2420, and M67. The open clusters span an age
range from 150 Myr to 4 Gyr and have metal abundances from [Fe/H] = -0.3 to
+0.09 dex. We have utilized these data to test the robustness of theoretical
main sequences constructed by several groups as denoted by the following
designations - Padova, Baraffe, Y^2, Geneva, and Siess. The comparisons of the
models with the observations have been performed in the [Mv, (B-V)o], [Mv,
(V-I)o], and [Mv, (V-K)o] colour-magnitude diagrams as well as the
distance-independent [(V-K)o, (B-V)o] and [(V-K)o, (V-I)o] two-colour diagrams.
We conclude that none of the theoretical models reproduce the observational
data in a consistent manner over the magnitude and colour range of the
unevolved main sequence. In particular, there are significant zeropoint and
shape differences between the models and the observations. We speculate that
the crux of the problem lies in the precise mismatch between theoretical and
observational colour-temperature relations. These results underscore the
importance of pursuing the study of stellar structure and stellar modelling
with even greater intensity.Comment: Accepted for publication in MNRAS. 12 pages, 37 figures, 4 tables.
High resolution figures available from
http://www.astro.ufl.edu/~aaron/opt_ir_figs
A systematic review on health resilience to economic crises
Background The health effects of recent economic crises differ markedly by population group. The objective of this systematic review is to examine evidence from longitudinal studies on factors influencing resilience for any health outcome or health behaviour among the general population living in countries exposed to financial crises. Methods We systematically reviewed studies from six electronic databases (EMBASE, Global Health, MEDLINE, PsycINFO, Scopus, Web of Science) which used quantitative longitudinal study designs and included: (i) exposure to an economic crisis; (ii) changes in health outcomes/behaviours over time; (iii) statistical tests of associations of health risk and/or protective factors with health outcomes/behaviours. The quality of the selected studies was appraised using the Quality Assessment Tool for Quantitative Studies. PRISMA reporting guidelines were followed. Results From 14,584 retrieved records, 22 studies met the eligibility criteria. These studies were conducted across 10 countries in Asia, Europe and North America over the past two decades. Ten socio-demographic factors that increased or protected against health risk were identified: gender, age, education, marital status, household size, employment/occupation, income/ financial constraints, personal beliefs, health status, area of residence, and social relations. These studies addressed physical health, mortality, suicide and suicide attempts, mental health, and health behaviours. Women’s mental health appeared more susceptible to crises than men’s. Lower income levels were associated with greater increases in cardiovascular disease, mortality and worse mental health. Employment status was associated with changes in mental health. Associations with age, marital status, and education were less consistent, although higher education was associated with healthier behaviours. Conclusions Despite widespread rhetoric about the importance of resilience, there was a dearth of studies which operationalised resilience factors. Future conceptual and empirical research is needed to develop the epidemiology of resilience
Clinical Utility and Concordance of Upper Urinary Tract Cytology and Biopsy in Predicting Clinicopathologic Features of Upper Urinary Tract Urothelial Carcinoma
5% of urothelial carcinoma occurs in the upper urinary tract (UUT), a challenging location to biopsy. We aim to evaluate concordance between biopsy, cytology, and resection specimens in a large upper tract urothelial carcinoma (UTUC) cohort.117 UTUC resections with UUT biopsy and/or cytology specimens from 2000–2016 were retrieved; pathologic material was re-reviewed, evaluated for concordance, and correlated with clinical information. 14% pre-operative biopsies, including 8 from renal pelvis and 6 from ureter, lacked neoplastic diagnoses. 77% diagnostic biopsies included subepithelial tissue; 11% demonstrated reclassification of grade and 30% demonstrated reclassification of invasion status. 26% of renal pelvis UTUC and 36% ureter UTUC were invasive only on resection. Of 18 UTUC reclassified from noninvasive high-grade papillary urothelial carcinoma (HGPUC) to invasive HGPUC, 39% had prior radical cystectomy (versus 8% invasive UTUC and 11% noninvasive UTUC with concordant biopsies). Most high-grade UTUC (88%) and some low-grade UTUC (58%) resections had abnormal cytology results. Biopsy-resection pairs with concordant invasion status and pairs with discordant invasion status showed similar rates of recurrence (38% versus 38%) and metastasis (25% versus 27%). 14% of UUT biopsies lacked diagnostic neoplastic material. Grade concordance between biopsy and resection was high (89%), but 30% of cases showed invasion only on resection. Subepithelial tissue was less commonly present in ureter biopsies, particularly from mid or proximal ureter. UTUC in patients with prior cystectomy were more likely to show invasion on resection but not biopsy
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Allowing a wildfire to burn: estimating the effect on future fire suppression costs
Where a legacy of aggressive wildland fire suppression has left forests in need of fuel reduction, allowing wildland fire to burn may provide fuel treatment benefits, thereby reducing suppression costs from subsequent fires. The least-cost-plus-net-value-change model of wildland fire economics includes benefits of wildfire in a framework for evaluating suppression options. In this study, we estimated one component of that benefit – the expected present value of the reduction in suppression costs for subsequent fires arising from the fuel treatment effect of a current fire. To that end, we employed Monte Carlo methods to generate a set of scenarios for subsequent fire ignition and weather events, which are referred to as sample paths, for a study area in central Oregon. We simulated fire on the landscape over a 100-year time horizon using existing models of fire behaviour, vegetation and fuels development, and suppression effectiveness, and we estimated suppression costs using an existing suppression cost model. Our estimates suggest that the potential cost savings may be substantial. Further research is needed to estimate the full least-cost-plus-net-value-change model. This line of research will extend the set of tools available for developing wildfire management plans for forested landscapes.Keywords: bio-economic modelling, wildland fire management, forest economics, forest fire polic
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