714 research outputs found

    Solar system chaos and the Paleocene-Eocene boundary age constrained by geology and astronomy

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    Astronomical calculations reveal the solar system's dynamical evolution, including its chaoticity, and represent the backbone of cyclostratigraphy and astrochronology. An absolute, fully calibrated astronomical time scale has hitherto been hampered beyond \sim50 Ma, because orbital calculations disagree before that age. Here we present geologic data and a new astronomical solution (ZB18a), showing exceptional agreement from \sim58 to 53 Ma. We provide a new absolute astrochronology up to 58 Ma and a new Paleocene-Eocene boundary age (56.01 ±\pm 0.05 Ma). We show that the Paleocene-Eocene Thermal Maximum (PETM) onset occurred near a 405-kyr eccentricity maximum, suggesting an orbital trigger. We also provide an independent PETM duration (170 ±\pm 30 kyr) from onset to recovery inflection. Our astronomical solution requires a chaotic resonance transition at \sim50 Ma in the solar system's fundamental frequencies.Comment: Supplementary materials available at this URL: www2.hawaii.edu/~zeebe/Astro.htm

    A Rare Case of Jejunal Arterio-Venous Fistula: Treatment with Superselective Catheter Embolization with a Tracker-18 Catheter and Microcoils

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    Arterio-venous fistulas may develop spontaneously, following trauma or infection, or be iatrogenic in nature. We present a rare case of a jejunal arterio- venous fistula in a 35-year-old man with a history of pancreatic head resection that had been performed two years previously because of chronic pancreatitis. The patient was admitted with acute upper abdominal pain, vomiting and an abdominal machinery-type bruit. The diagnosis of a jejunal arterio-venous fistula was established by MR imaging. Transfemoral angiography was performed to assess the possibility of catheter embolization. The angiographic study revealed a small aneurysm of the third jejunal artery, abnormal early filling of dilated jejunal veins and marked filling of the slightly dilated portal vein (13-14 mm). We considered the presence of segmental portal hypertension. The patient was treated with coil embolization in the same angiographic session. This case report demonstrates the importance of auscultation of the abdomen in the initial clinical examination. MR imaging and color Doppler ultrasound are excellent noninvasive tools in establishing the diagnosis. The role of interventional radiological techniques in the treatment of early portal hypertension secondary to jejunal arterio-venous fistula is discussed at a time when this condition is still asymptomatic. A review of the current literature is include

    Variability of indigestible NDF in C3 and C4 forages and implications on the resulting feed energy values and potential microbial protein synthesis in dairy cattle

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    Estimation of indigestible neutral detergent fibre (iNDF) is necessary for accurate and precise predictions of feed energy values and potential microbial protein from digested NDF in the rumen. Due to lengthy laboratory procedures, iNDF has been estimated using the formula ADLÃ?2.4 (iNDF2.4). The relationship between iNDF and acid detergent lignin (ADL) is more variable, across and within forage species. The purpose of our study was then to assess the variability of iNDF and respective implications on ration fine-tuning for dairy cattle. Sixty forages, including grasses, maize silages and lucerne hays, were fermented in vitro from 0 to 240 hours. Residual NDF of the fermented samples were obtained at 0, 6, 12, 24, 36, 48, 72, 96, 120, 144, 216 and 240 h, with the last value assumed to represent iNDF (iNDF240).This was used to obtain the potentially digestible NDF fraction (pdNDF). Rates of digestion of pdNDF were obtained assuming a first order decay. Simulations with the Cornell Net Carbohydrate and Protein System (CNCPS v 6.1, 2012) were done to evaluate the effects of the different estimated iNDF and NDF rate of digestion (kd) on energy and microbial protein estimations, assuming the requirements of a high-yielding lactating cow and a standard TMR with at least 50% forage. Results were dependent on the amount of forage and respective NDF and ADL. The iNDF240 values resulted between 1% and 136% higher than the iNDF2.4 values. The reduced pdNDF pool resulted in both lower cell wall linked protein in the rumen and microbial protein of around 5 to 165 g, and, as a consequence, on a total decreased metabolizable protein for milk. Use of iNDF240 showed consistently lower metabolizable energy (ME) between 2 and 10 MJ/day, compared to when using iNDF2.4. The improved metabolizable protein (MP) and ME values would result in 0.3 to 3.2 kg/d less milk when using iNDF2.4. This research demonstrates how points later in the fermentation curve, even if not biologically relevant for the cow, result in a more accurate and precise estimation of the rate of NDF digestibility. Indigestible NDF estimated at 240 h would give better predictions of rumen parameters in models like the CNCPS and better fine-tuning in dairy cow diets, especially when using high forage and/or NDF rations.http://www.sasas.co.zaam201

    The Small World of Psychopathology

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    Background: Mental disorders are highly comorbid: people having one disorder are likely to have another as well. We explain empirical comorbidity patterns based on a network model of psychiatric symptoms, derived from an analysis of symptom overlap in the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV). Principal Findings: We show that a) half of the symptoms in the DSM-IV network are connected, b) the architecture of these connections conforms to a small world structure, featuring a high degree of clustering but a short average path length, and c) distances between disorders in this structure predict empirical comorbidity rates. Network simulations of Major Depressive Episode and Generalized Anxiety Disorder show that the model faithfully reproduces empirical population statistics for these disorders. Conclusions: In the network model, mental disorders are inherently complex. This explains the limited successes of genetic, neuroscientific, and etiological approaches to unravel their causes. We outline a psychosystems approach to investigate the structure and dynamics of mental disorders

    Quantitative exposure to livestock-associated MRSA ST398 of pig slaughterhouse workers

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    Objectives: To quantify livestock-associated MRSA (LA-MRSA) exposure to workers in pig slaughterhouses and assess associated risk factors for carriage in slaughterhouse workers. Methods: A cross-sectional study in three Dutch pig slaughterhouses was undertaken. Nasal swabs of 341 participants, surface wipes, air, and glove samples were screened for presence of MRSA. MRSA was quantitatively determined on gloves and in air samples by culturing and real-time PCR

    Fast and accurate modelling of longitudinal and repeated measures neuroimaging data

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    Despite the growing importance of longitudinal data in neuroimaging, the standard analysis methods make restrictive or unrealistic assumptions (e.g., assumption of Compound Symmetry—the state of all equal variances and equal correlations—or spatially homogeneous longitudinal correlations). While some new methods have been proposed to more accurately account for such data, these methods are based on iterative algorithms that are slow and failure-prone. In this article, we propose the use of the Sandwich Estimator (SwE) method which first estimates the parameters of interest with a simple Ordinary Least Square model and second estimates variances/covariances with the “so-called” SwE which accounts for the within-subject correlation existing in longitudinal data. Here, we introduce the SwE method in its classic form, and we review and propose several adjustments to improve its behaviour, specifically in small samples. We use intensive Monte Carlo simulations to compare all considered adjustments and isolate the best combination for neuroimaging data. We also compare the SwE method to other popular methods and demonstrate its strengths and weaknesses. Finally, we analyse a highly unbalanced longitudinal dataset from the Alzheimer's Disease Neuroimaging Initiative and demonstrate the flexibility of the SwE method to fit within- and between-subject effects in a single model. Software implementing this SwE method has been made freely available at http://warwick.ac.uk/tenichols/SwE

    Caregiver Willingness to Give TPT to Children Living with Drug-Resistant TB Patients

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    Pediatric household contacts (HHCs) of patients with multidrug-resistant TB (MDR-TB) are at high risk of infection and active disease. Evidence of caregiver willingness to give MDR-TB preventive therapy (TPT) to children is limited.METHODS This was a cross-sectional study of HHCs of patients with MDR-TB to assess caregiver willingness to give TPT to children aged \u3c13 years.RESULTS Of 743 adult and adolescent HHCs, 299 reported caring for children aged \u3c13 years of age. The median caregiver age was 35 years (IQR 27-48); 75% were women. Among caregivers, 89% were willing to give children MDR TPT. In unadjusted analyses, increased willingness was associated with TB-related knowledge (OR 5.1, 95% CI 2.3-11.3), belief that one can die of MDR-TB (OR 5.2, 95% CI 1.2-23.4), concern for MDR-TB transmission to child (OR 4.5, 95% CI 1.6-12.4), confidence in properly taking TPT (OR 4.5, 95% CI 1.6-12.6), comfort telling family about TPT (OR 5.5, 95% CI 2.1-14.3), and willingness to take TPT oneself (OR 35.1, 95% CI 11.0-112.8).CONCLUSIONS A high percentage of caregivers living with MDR- or rifampicin-resistant TB patients were willing to give children a hypothetical MDR TPT. These results provide important evidence for the potential uptake of effective MDR TPT when implemented
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