446 research outputs found

    Rapid sediment re-deposition may limit carbon release during catastrophic thermokarst lake drainage

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    ACKNOWLEDGMENTS We thank Georgina Heldreich for valuable discussions on delta formation, and the two constructive anonymous reviews, which greatly improved the manuscript.Peer reviewedPublisher PD

    Outcrop conservation : Promoting accessibility, inclusivity, and reproducibility through digital preservation

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    We thank Georgina Heldreich for providing useful comments on an early draft of the manuscript. We gratefully acknowledge the detailed and constructive reviews by Kim Senger and two anonymous reviewers, all of which greatly improved the manuscript.Peer reviewedPublisher PD

    On the dynamics of planetesimals embedded in turbulent protoplanetary discs with dead zones

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    (abridged) Accretion in protoplanetary discs is thought to be driven by [...] turbulence via the magnetorotational instability (MRI). Recent work has shown that a planetesimal swarm embedded in a fully turbulent disc is subject to strong excitation of the velocity dispersion, leading to collisional destruction of bodies with radii R_p < 100 km. Significant diffusion of planetesimal semimajor axes also arises, leading to large-scale spreading of the planetesimal population throughout the inner regions of the protoplanetary disc, in apparent contradiction of constraints provided by the distribution of asteroids within the asteroid belt. In this paper, we examine the dynamics of planetesimals embedded in vertically stratified turbulent discs, with and without dead zones. Our main aims are to examine the turbulent excitation of the velocity dispersion, and the radial diffusion, of planetesimals in these discs. We employ three dimensional MHD simulations [...], along with an equilibrium chemistry model [...] We find that planetesimals in fully turbulent discs develop large random velocities that will lead to collisional destruction/erosion for bodies with sizes below 100 km, and undergo radial diffusion on a scale \sim 2.5 au over a 5 Myr disc life time. But planetesimals in a dead zone experience a much reduced excitation of their random velocities, and equilibrium velocity dispersions lie between the disruption thresholds for weak and strong aggregates for sizes R_p < 100 km. We also find that radial diffusion occurs over a much reduced length scale \sim 0.25 au over the disc life time, this being consistent with solar system constraints. We conclude that planetesimal growth via mutual collisions between smaller bodies cannot occur in a fully turbulent disc. By contrast, a dead zone may provide a safe haven in which km-sized planetesimals can avoid mutual destruction through collisions.Comment: 18 pages, 13 figures, 3 tables, MNRAS in press, minor corrections to match the published versio

    Increased survival with enzalutamide in prostate cancer after chemotherapy

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    Contains fulltext : 108324.pdf (publisher's version ) (Open Access)BACKGROUND: Enzalutamide (formerly called MDV3100) targets multiple steps in the androgen-receptor-signaling pathway, the major driver of prostate-cancer growth. We aimed to evaluate whether enzalutamide prolongs survival in men with castration-resistant prostate cancer after chemotherapy. METHODS: In our phase 3, double-blind, placebo-controlled trial, we stratified 1199 men with castration-resistant prostate cancer after chemotherapy according to the Eastern Cooperative Oncology Group performance-status score and pain intensity. We randomly assigned them, in a 2:1 ratio, to receive oral enzalutamide at a dose of 160 mg per day (800 patients) or placebo (399 patients). The primary end point was overall survival. RESULTS: The study was stopped after a planned interim analysis at the time of 520 deaths. The median overall survival was 18.4 months (95% confidence interval [CI], 17.3 to not yet reached) in the enzalutamide group versus 13.6 months (95% CI, 11.3 to 15.8) in the placebo group (hazard ratio for death in the enzalutamide group, 0.63; 95% CI, 0.53 to 0.75; P<0.001). The superiority of enzalutamide over placebo was shown with respect to all secondary end points: the proportion of patients with a reduction in the prostate-specific antigen (PSA) level by 50% or more (54% vs. 2%, P<0.001), the soft-tissue response rate (29% vs. 4%, P<0.001), the quality-of-life response rate (43% vs. 18%, P<0.001), the time to PSA progression (8.3 vs. 3.0 months; hazard ratio, 0.25; P<0.001), radiographic progression-free survival (8.3 vs. 2.9 months; hazard ratio, 0.40; P<0.001), and the time to the first skeletal-related event (16.7 vs. 13.3 months; hazard ratio, 0.69; P<0.001). Rates of fatigue, diarrhea, and hot flashes were higher in the enzalutamide group. Seizures were reported in five patients (0.6%) receiving enzalutamide. CONCLUSIONS: Enzalutamide significantly prolonged the survival of men with metastatic castration-resistant prostate cancer after chemotherapy. (Funded by Medivation and Astellas Pharma Global Development; AFFIRM ClinicalTrials.gov number, NCT00974311.)

    Genome-wide, high-content siRNA screening identifies the Alzheimer's genetic risk factor FERMT2 as a major modulator of APP metabolism

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    Genome-wide association studies (GWASs) have identified 19 susceptibility loci for Alzheimer’s disease (AD). However, understanding how these genes are involved in the pathophysiology of AD is one of the main challenges of the “post-GWAS” era. At least 123 genes are located within the 19 susceptibility loci; hence, a conventional approach (studying the genes one by one) would not be time- and cost-effective. We therefore developed a genome-wide, high-content siRNA screening approach and used it to assess the functional impact of gene under-expression on APP metabolism. We found that 832 genes modulated APP metabolism. Eight of these genes were located within AD susceptibility loci. Only FERMT2 (a β3-integrin co-activator) was also significantly associated with a variation in cerebrospinal fluid Aβ peptide levels in 2886 AD cases. Lastly, we showed that the under-expression of FERMT2 increases Aβ peptide production by raising levels of mature APP at the cell surface and facilitating its recycling. Taken as a whole, our data suggest that FERMT2 modulates the AD risk by regulating APP metabolism and Aβ peptide production

    Subsequent Chemotherapy and Treatment Patterns After Abiraterone Acetate in Patients with Metastatic Castration-resistant Prostate Cancer: Post Hoc Analysis of COU-AA-302.

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    Background Treatment patterns for metastatic castration-resistant prostate cancer (mCRPC) have changed substantially in the last few years. In trial COU-AA-302 (chemotherapy-naïve men with mCRPC), abiraterone acetate plus prednisone (AA) significantly improved radiographic progression-free survival and overall survival (OS) when compared to placebo plus prednisone (P).Objective This post hoc analysis investigated clinical responses to docetaxel as first subsequent therapy (FST) among patients who progressed following protocol-specified treatment with AA, and characterized subsequent treatment patterns among older (≥75 yr) and younger (<75 yr) patient subgroups.Design, setting, and participants Data were collected at the final OS analysis (96% of expected death events). Subsequent therapy data were prospectively collected, while response and discontinuation data were collected retrospectively following discontinuation of the study drug.Intervention At the discretion of the investigator, 67% (365/546) of patients from the AA arm received subsequent treatment with one or more agents approved for mCRPC.Outcome measurements and statistical analysis Efficacy analysis was performed for patients for whom baseline and at least one post-baseline prostate-specific antigen (PSA) values were available.Results and limitations Baseline and at least one post-baseline PSA values were available for 100 AA patients who received docetaxel as FST. While acknowledging the limitations of post hoc analyses, 40% (40/100) of these patients had an unconfirmed ≥50% PSA decline with first subsequent docetaxel therapy, and 27% (27/100) had a confirmed ≥50% PSA decline. The median docetaxel treatment duration among these 100 patients was 4.2 mo. Docetaxel was the most common FST among older and younger patients from each treatment arm. However, 43% (79/185) of older patients who progressed on AA received no subsequent therapy for mCRPC, compared with 17% (60/361) of younger patients.Conclusions Patients with mCRPC who progress with AA treatment may still derive benefit from subsequent docetaxel therapy. These data support further assessment of treatment patterns following AA treatment for mCRPC, particularly among older patients.Trial registration ClinicalTrials.gov NCT00887198.Patient summary Treatment patterns for advanced prostate cancer have changed substantially in the last few years. This additional analysis provides evidence of clinical benefit for subsequent chemotherapy in men with advanced prostate cancer whose disease progressed after treatment with abiraterone acetate. Older patients were less likely to be treated with subsequent therapy

    Walk-ins seeking treatment at an emergency department or general practitioner out-of-hours service: a cross-sectional comparison

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    Background Emergency Departments (ED) in Switzerland are faced with increasing numbers of patients seeking non-urgent treatment. The high rate of walks-ins with conditions that may be treated in primary care has led to suggestions that those patients would best cared for in a community setting rather than in a hospital. Efficient reorganisation of emergency care tailored to patients needs requires information on the patient populations using the various emergency services currently available. The aim of this study is to evaluate the differences between the characteristics of walk-in patients seeking treatment at an ED and those of patients who use traditional out-of-hours GP (General Practitioner) services provided by a GP-Cooperative (GP-C). Methods In 2007 and 2009 data was collected covering all consecutive patient-doctor encounters at the ED of a hospital and all those occurring as a result of contacting a GP-C over two evaluation periods of one month each. Comparison was made between a GP-C and the ED of the Waid City Hospital in Zurich. Patient characteristics, time and source of referral, diagnostic interventions and mode of discharge were evaluated. Medical problems were classified according to the International Classification of Primary Care (ICPC-2). Patient characteristics were compared using non-parametric tests and multiple logistic regression analysis was applied to investigate independent determinants for contacting a GP-C or an ED. Results Overall a total of 2974 patient encounters were recorded. 1901 encounters were walk-ins and underwent further analysis (ED 1133, GP-C 768). Patients consulting the GP-C were significantly older (58.9 vs. 43.8 years), more often female (63.5 vs. 46.9%) and presented with non-injury related medical problems (93 vs. 55.6%) in comparison with patients at the ED. Independent determining factors for ED consultation were injury, male gender and younger age. Walk-in distribution in both settings was equal over a period of 24 hours and most common during daytime hours (65%). Outpatient care was predominant in both settings but significantly more so at the GP-C (79.9 vs. 85.7%). Conclusions We observed substantial differences between the two emergency settings in a non gate-keeping health care system. Knowledge of the distribution of diagnoses, their therapy, of diagnostic measures and of the factors which determine the patients' choice of the ED or the GP-C is essential for the efficient allocation of resources and the reduction of costs
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