1,049 research outputs found

    Ureteritis Cystica: Important Consideration in the Differential Diagnosis of Acute Renal Colic

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    Ureteritis cystica is an uncommon cause of acute renal pain. The aetiology remains unclear and the diagnosis may be difficult to establish. We report the case of a 29 year old woman with a history of repeated urinary tract infections presenting with acute renal colic in the absence of lithiasis. We review the diagnostic tools available to make the diagnosis and the recent pertinent literature

    Explosive Contagion in Networks.

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    The spread of social phenomena such as behaviors, ideas or products is an ubiquitous but remarkably complex phenomenon. A successful avenue to study the spread of social phenomena relies on epidemic models by establishing analogies between the transmission of social phenomena and infectious diseases. Such models typically assume simple social interactions restricted to pairs of individuals; effects of the context are often neglected. Here we show that local synergistic effects associated with acquaintances of pairs of individuals can have striking consequences on the spread of social phenomena at large scales. The most interesting predictions are found for a scenario in which the contagion ability of a spreader decreases with the number of ignorant individuals surrounding the target ignorant. This mechanism mimics ubiquitous situations in which the willingness of individuals to adopt a new product depends not only on the intrinsic value of the product but also on whether his acquaintances will adopt this product or not. In these situations, we show that the typically smooth (second order) transitions towards large social contagion become explosive (first order). The proposed synergistic mechanisms therefore explain why ideas, rumours or products can suddenly and sometimes unexpectedly catch on

    Leaf Morphology, Taxonomy and Geometric Morphometrics: A Simplified Protocol for Beginners

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    Taxonomy relies greatly on morphology to discriminate groups. Computerized geometric morphometric methods for quantitative shape analysis measure, test and visualize differences in form in a highly effective, reproducible, accurate and statistically powerful way. Plant leaves are commonly used in taxonomic analyses and are particularly suitable to landmark based geometric morphometrics. However, botanists do not yet seem to have taken advantage of this set of methods in their studies as much as zoologists have done. Using free software and an example dataset from two geographical populations of sessile oak leaves, we describe in detailed but simple terms how to: a) compute size and shape variables using Procrustes methods; b) test measurement error and the main levels of variation (population and trees) using a hierachical design; c) estimate the accuracy of group discrimination; d) repeat this estimate after controlling for the effect of size differences on shape (i.e., allometry). Measurement error was completely negligible; individual variation in leaf morphology was large and differences between trees were generally bigger than within trees; differences between the two geographic populations were small in both size and shape; despite a weak allometric trend, controlling for the effect of size on shape slighly increased discrimination accuracy. Procrustes based methods for the analysis of landmarks were highly efficient in measuring the hierarchical structure of differences in leaves and in revealing very small-scale variation. In taxonomy and many other fields of botany and biology, the application of geometric morphometrics contributes to increase scientific rigour in the description of important aspects of the phenotypic dimension of biodiversity. Easy to follow but detailed step by step example studies can promote a more extensive use of these numerical methods, as they provide an introduction to the discipline which, for many biologists, is less intimidating than the often inaccessible specialistic literature

    Characteristic Evolution and Matching

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    I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress in characteristic evolution is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black hole spacetime. Cauchy codes have now been successful at simulating all aspects of the binary black hole problem inside an artificially constructed outer boundary. A prime application of characteristic evolution is to extend such simulations to null infinity where the waveform from the binary inspiral and merger can be unambiguously computed. This has now been accomplished by Cauchy-characteristic extraction, where data for the characteristic evolution is supplied by Cauchy data on an extraction worldtube inside the artificial outer boundary. The ultimate application of characteristic evolution is to eliminate the role of this outer boundary by constructing a global solution via Cauchy-characteristic matching. Progress in this direction is discussed.Comment: New version to appear in Living Reviews 2012. arXiv admin note: updated version of arXiv:gr-qc/050809

    Intraoperative PaO2 is not related to the development of surgical site infections after major cardiac surgery

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    Producción CientíficaBackground: The perioperative use of high inspired oxygen fraction (FIO2) for preventing surgical site infections (SSIs) has demonstrated a reduction in their incidence in some types of surgery however there exist some discrepancies in this respect. The aim of this study was to analyze the relationship between PaO2 values and SSIs in cardiac patients. Methods: We designed a prospective study in which 1,024 patients undergoing cardiac surgery were analyzed. Results: SSIs were observed in 5.3% of patients. There was not significant difference in mortality at 30 days between patients with and without SSIs. In the uni and multivariate analysis no differences in function of the inspired oxygen fraction administrated were observed. Conclusions: We observed that the PaO2 in adult cardiac surgery patients was not related to SSI rate

    State of emergency medicine in Spain

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    Spain has universal public health care coverage. Emergency care provisions are offered to patients in different modalities and levels according to the characteristics of the medical complaint: at primary care centers (PCC), in an extrahospital setting by emergency medical services (EMS) and at hospital emergency departments (ED). We have more than 3,000 PCCs, which are run by family doctors (general practitioners) and pediatricians. On average, there is 1 PCC for every 15,000 to 20,000 inhabitants, and every family doctor is in charge of 1,500 to 2,000 citizens, although less populated zones tend to have lower ratios. Doctors spend part of their duty time in providing emergency care to their own patients. While not fully devoted to emergency medicine (EM) practice, they do manage minor emergencies. However, Spanish EMSs contribute hugely to guarantee population coverage in all situations. These EMS are run by EM technicians (EMT), nurses and doctors, who usually work exclusively in the emergency arena. EDs dealt with more than 25 million consultations in 2008, which implies, on average, that one out of two Spaniards visited an ED during this time. They are usually equipped with a wide range of diagnostic tools, most including ultrasonography and computerized tomography scans. The academic and training background of doctors working in the ED varies: nearly half lack any structured specialty residence training, but many have done specific master or postgraduate studies within the EM field. The demand for emergency care has grown at an annual rate of over 4% during the last decade. This percentage, which was greater than the 2% population increase during the same period, has outpaced the growth in ED capacity. Therefore, Spanish EDs become overcrowded when the system exerts minimal stress. Despite the high EM caseload and the potential severity of the conditions, training in EM is still unregulated in Spain. However, in April 2009 the Spanish Minister of Health announced the imminent approval of an EM specialty, allowing the first EM resident to officially start in 2011. Spanish emergency physicians look forward to the final approval, which will complete the modernization of emergency health care provision in Spain

    Efficiency of BRCAPRO and Myriad II mutation probability thresholds versus cancer history criteria alone for BRCA1/2 mutation detection

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    Considerable differences exist amongst countries in the mutation probability methods and thresholds used to select patients for BRCA1/2 genetic screening. In order to assess the added value of mutation probability methods, we have retrospectively calculated the BRCAPRO and Myriad II probabilities in 306 probands who had previously been selected for DNA-analysis according to criteria based on familial history of cancer. DNA-analysis identified 52 mutations (16.9%) and 11 unclassified variants (UVs, 3.6%). Compared to cancer history, a threshold ≥10% with BRCAPRO or with Myriad II excluded about 40% of the patients from analysis, including four with a mutation and probabilities <10% with both programs. All four probands had a BRCA2 mutation. BRCAPRO and Myriad II showed similar specificity at 10% threshold, overall BRCAPRO was more sensitive than Myriad II for the detection of mutations. Only two of the probands with an UV had probabilities >20% with BRCAPRO and Myriad II. In summary, BRCAPRO and Myriad II are more efficient than cancer history alone to exclude patients without a mutation. BRCAPRO performs better for the detection of BRCA1 mutations than of BRCA2 mutations. The Myriad II scores provided no additional information than the BRCAPRO scores alone for the detection of patients with a mutation. The use of thresholds excluded from analysis the majority of patients carrying an UV
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