629 research outputs found

    Parameter estimation with Bayesian estimation applied to multiple species in the presence of biases and correlations

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    The original formulation of Bayesian estimation applied to multiple species (BEAMS) showed how to use a data set contaminated by points of multiple underlying types to perform unbiased parameter estimation. An example is cosmological parameter estimation from a photometric supernova sample contaminated by unknown Type Ibc and II supernovae. Where other methods require data cuts to increase purity, BEAMS uses all of the data points in conjunction with their probabilities of being each type. Here we extend the BEAMS formalism to allow for correlations between the data and the type probabilities of the objects as can occur in realistic cases. We show with simple simulations that this extension can be crucial, providing a 50 per cent reduction in parameter estimation variance when such correlations do exist. We then go on to perform tests to quantify the importance of the type probabilities, one of which illustrates the effect of biasing the probabilities in various ways. Finally, a general presentation of the selection bias problem is given, and discussed in the context of future photometric supernova surveys and BEAMS, which lead to specific recommendations for future supernova survey

    Studies in molecular structure, symmetry and conformation. Part XIV. Crystal and molecular structure of L-isoleucine hydrochloride monohydrate form II

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    The crystal structure of a new form of L-isoleucine hydrochloride monohydrate C6H13O2NHClH2O (termed form II) has been determined using three-dimensional photographic data. This differs conformationally from the hydrochloride derivative (termed form I, Trommel and Bijvoet 1954) reported earlier. The crystal belongs to the orthorhombic space group P212121 with cell dimensions, a=5.87±0.01, b=24.77±0.02 and c=6.85±0.01Å and four molecules per cell, ρobs=1.240g/cm3, ρcal=1.238 g/cm3, μ for CuKα=32.6 cm-1

    Gonadotropins for pubertal induction in males with hypogonadotropic hypogonadism: systematic review and meta-analysis.

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    OBJECTIVE: Hypogonadotropic hypogonadism is characterized by inadequate secretion of pituitary gonadotropins, leading to absent, partial, or arrested puberty. In males, classical treatment with testosterone promotes virilization but not testicular growth or spermatogenesis. To quantify treatment practices and efficacy, we systematically reviewed all studies investigating gonadotropins for the achievement of pubertal outcomes in males with hypogonadotropic hypogonadism. DESIGN: Systematic review and meta-analysis. METHODS: A systematic review of Medline, Embase, Global Health, and PsycINFO databases in December 2022. Risk of Bias 2.0/Risk Of Bias In Non-randomized Studies of Interventions/National Heart, Lung, and Blood Institute tools for quality appraisal. Protocol registered on PROSPERO (CRD42022381713). RESULTS: After screening 3925 abstracts, 103 studies were identified including 5328 patients from 21 countries. The average age of participants was <25 years in 45.6% (n = 47) of studies. Studies utilized human chorionic gonadotropin (hCG) (n = 93, 90.3% of studies), human menopausal gonadotropin (n = 42, 40.8%), follicle-stimulating hormone (FSH) (n = 37, 35.9%), and gonadotropin-releasing hormone (28.2% n = 29). The median reported duration of treatment/follow-up was 18 months (interquartile range 10.5-24 months). Gonadotropins induced significant increases in testicular volume, penile size, and testosterone in over 98% of analyses. Spermatogenesis rates were higher with hCG + FSH (86%, 95% confidence interval [CI] 82%-91%) as compared with hCG alone (40%, 95% CI 25%-56%). However, study heterogeneity and treatment variability were high. CONCLUSIONS: This systematic review provides convincing evidence of the efficacy of gonadotropins for pubertal induction. However, there remains substantial heterogeneity in treatment choice, dose, duration, and outcomes assessed. Formal guidelines and randomized studies are needed

    Clinical Guidance for the Management of Patients with Urothelial Cancers During the COVID-19 Pandemic - Rapid Review.

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    The current COVID-19 pandemic presents a substantial obstacle to cancer patient care. Data from China as well as risk models suppose that cancer patients, particularly those on active, immunosuppressive therapies are at higher risks of severe infection from the illness. In addition, staff illness and restructuring of services to deal with the crisis will inevitably place treatment capacities under significant strain. These guidelines aim to expand on those provided by NHS England regarding cancer care during the coronavirus pandemic by examining the known literature and provide guidance in managing patients with urothelial and rarer urinary tract cancers. In particular, they address the estimated risk and benefits of standard treatments and consider the alternatives in the current situation. As a result, it is recommended that this guidance will help form a framework for shared decision making with patients. Moreover, they do not advise a one-size-fits-all approach but recommend continual assessment of the situation with discussion within and between centres

    A Case of Xanthogranulomatous Pyelonephritis Associated with Renoduodenal Fistula

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    Xanthogranulomatous pyelonephritis (XGP) is a rare form of pyelonephritis associated with repeated infection, chronic inflammation, and obstruction. Various fistulas, including those to the intestine, are a known association with XGP. Here, a 55-year-old woman with a history of multiple previous renal calculi presented with dysuria and back pain. Contrast-enhanced computed tomography (CT) revealed a soft tissue density in her renal pelvis and perirenal space consistent with XGP along with a tract connecting the upper pole of her right kidney to the second portion of the duodenum. This finding was subsequently confirmed during percutaneous nephrostomy placement, stent placement, a small bowel follow-through study, and upper endoscopy. She was diagnosed with XGP with associated renoduodenal fistula, eventually treated by open nephrectomy with fistula takedown. Histopathologic analysis was consistent with the diagnosis of XGP with no malignant or infectious cause of the fistula. XGP should be considered in the diagnosis of patients with dysuria and back pain, especially when a history of obstruction or chronic inflammation. Associated fistulas should also be considered prior to surgical management to prevent complications
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