1,179 research outputs found

    MODELS OF TURBULENCE. APPLICATIONS TO PARTICULATE MIXING INDUCED BY TRAFFIC FLOW IN URBAN AREAS.

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    In this work we address our attention to the estimation of the contribution of non-exhaust sources, like brake abrasion, tire and road wear and resuspension of particles, to the final PM air concentration; particularly we focus our investigation on the resuspension of PM deposited on road pavement surfaces and raised by the air turbulence produced by the vehicles flux, under urban and extra-urban traffic conditions. Our approach to the problem is based on modeling techniques. We refer to measurement data from literature to determine the selected empirical parameters contained in our models. Analytical models based on algebraic eddy diffusivity hypothesis are applied to describe the mean statistical component of flow generated by air recirculation inside a canyon and by the far-wake structure besides moving vehicles of simplified geometrical shapes. The analysis of the far wake solutions is suitable to the description of vehicle wakes interaction, which permits to apply our analysis to different driving cycles conditions. Numerical simulations based on finite element discretization of suitable two-equation turbulence models are employed to describe near-wake structures, which cause the strongest mixing of atmospheric pollutants and resuspension of road dust. These different components of turbulence fields at different scales of the street geometry are composed to define a set of operational and numerical models for the dispersion dynamics at the canyon scale of two classes of PM10 pollutants, corresponding to a Soot and a road dust components. The deposition and the resuspension of pollutants are described by resistance and filtration models on porous asphalts, inserting the corresponding terms in the dispersion equations as suitable boundary conditions on the ground. We estimate the resuspension fraction of traffic-related PM10 emissions at the tailpipe, through a simplified linear-emission model, considering representative data describing traffic statistics coming from empirical data. Profile laws of resuspension factors are drawn, for different vehicles geometries and velocities, and how resuspension changes with different asphalt characteristics. The results are applied to typical traffic situations in the city of Milan, studying the effect of implementations of different reduction scenarios to the total amount of traffic-related PM10 emissions. The results point at a new approach to the local PM10 reduction policies, based on more effective asphalt design and maintenance. Finally, we apply one of the dispersion operational models to the case of a congested urban traffic configuration in a canyon street, in order to obtain the pollutant spatial distribution

    Aprovechamiento de materiales locales en la estructura de pavimentos urbanos económicos

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    Se estudiaron las propiedades de un suelo representativo del partido de 25 de Mayo (Prov. de Buenos Aires) y su zona de influencia, con el objeto de conocer la posibilidad de utilizarlo como base y sub-base de pavimentos urbanos. Se analizó el comportamiento del suelo, realizando mezclas con emulsión bituminosa superestable EBL2, como así también mezclas de suelo-cemento. De la comparación de ambos casos surgen consideraciones técnico-económicas, en base a las cuales se dan posibles soluciones de pavimento.In this paper were studied the properties of a representative soil of 25 de Mayo district, in the Buenos Aires Province, with the object to establish the possibility of its use as a base and sub-base in urban pavements. The soil behaviour vms analyzed making mixtures with su- perstnble EBL2 bituminous emulsions and also with soil-cement mixtures. The results obtained with both mixtures were compared and technical and economical considerations were given

    Antirheumatic drugs and reproduction in women and men with chronic arthritis.

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    The impact of rheumatic disease on fertility and reproduction can be remarkable. Many disease-related factors can influence patients' sexual functioning, perturb fertility and limit family planning. Antirheumatic pharmacological treatment can also have a crucial role in this field. Proper counselling, preferably provided by a multidisciplinary team of rheumatologists, obstetricians, gynaecologists and neonatologists, is recommended for patients taking antirheumatic drugs, not only at the beginning, but also during the course of treatment. Paternal exposure to antirheumatic drugs was not found to be specifically associated with congenital malformation and adverse pregnancy outcome, therefore discontinuation of these drugs while planning for conception should be weighed against the risk of disease flare. Drugs in Food and Drug Administration (FDA) category 'X' should be withdrawn in a timely manner in women who desire a pregnancy. Meanwhile, disease control can be achieved with anti-tumour necrosis factor (TNF)-α agents, which are not teratogenic drugs. If maternal disease control is permissive, they can be stopped as soon as the pregnancy test turns positive and be resumed during pregnancy in case of a flare

    Relationship between fatty liver and glucose metabolism: A cross-sectional study in 571 obese children

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    BACKGROUND AND AIMS: Early onset type 2 diabetes mellitus (T2DM) is associated with obesity, insulin resistance and impaired beta-cell function. Non-alcoholic fatty liver disease (NAFLD) may be an independent risk factor for T2DM. We investigated the relationship between NAFLD and glucose metabolism in a large sample of obese children. METHODS AND RESULTS: A total of 571 obese children (57% males and 43% females) aged 8-18 years were consecutively studied at a tertiary care centre specialised in paediatric obesity. Liver ultrasonography was used to diagnose NAFLD after exclusion of hepatitis B and C and alcohol consumption. Oral-glucose tolerance testing (OGTT) was performed; insulin sensitivity was evaluated by using the insulin sensitivity index (ISI) and beta-cell function by using the ratio between the incremental areas under the curve (AUC) of insulin and glucose (incAUCins/incAUCglu). A total of 41% of the obese children had NAFLD. Impaired glucose tolerance or T2DM was present in 25% of the children with NAFLD versus 8% of those without it (p<0.001). Children with NAFLD had higher body mass index (BMI), fasting glucose, 120-min OGTT glucose, incAUCins/incAUCglu and lower ISI as compared with children without NAFLD (p</=0.002). At bootstrapped multivariable median regression analysis controlling for gender, age, pubertal status and BMI, NAFLD was an independent predictor of 120-min OGTT glucose and ISI, but not of incAUCins/incAUCglu. Similar findings were obtained using continuous liver steatosis as the predictor, instead of dichotomous NAFLD. CONCLUSION: NAFLD was present in 41% of our obese children and was associated with higher insulin resistance, but not with impaired beta-cell function

    Long-term neuropsychological sequelae, emotional wellbeing and quality of life in patients with acquired thrombotic thrombocytopenic purpura

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    Neurological symptoms related to microthrombosis are the hallmark of acute manifestations of acquired thrombotic thrombocytopenic purpura. Despite the achievement of hematological remission, patients may report persisting neurological impairment that affects their quality of life. To assess the long-term neuropsychological consequences of acute thrombotic thrombocytopenic purpura, we recruited 35 acquired thrombotic thrombocytopenic purpura patients (77% females, median age at onset 41 years, interquartile range 35-48) regularly followed at our out-patient clinic of thrombotic microangiopathies in Milan (Italy) from December 2015 to October 2016. Patients underwent a psychological evaluation of memory and attentional functions, emotional wellbeing and health-related quality of life at least 3 months after their last acute thrombotic thrombocytopenic purpura event (median 36 months, interquartile range 17-54). During the psychological consultation, 17 patients (49%) referred persisting subjective neurological impairment in the frame of a remission phase, with at least one symptom as disorientation, loss of concentration, dizziness, lack of balance, headache and diplopia. Neuropsychological assessment revealed lower scores than the Italian general population pertaining to direct, indirect and deferred memory. A higher degree of impairment of memory domains was found in patients with neurological involvement at the time of presentation of the first acute thrombotic thrombocytopenic purpura episode. Anxiety and depression were detected in 7 (20%) and 15 (43%) patients, respectively. Health-related quality of life was lower than the Italian general population, with mental domains more impacted than physical domains (mean difference 58.43, 95% confidence interval [-71.49, -45.37]). Our study demonstrates compromised memory and attention functions, persisting anxiety/depression symptoms and a generally reduced quality of life in patients surviving from acute acquired thrombotic thrombocytopenic purpura. New clinical strategies should be considered to improve these symptoms

    Copyright and the Use of Images as Biodiversity Data [Forum paper]

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    Taxonomy is the discipline responsible for charting the world’s organismic diversity, understanding ancestor/descendant relationships, and organizing all species according to a unified taxonomic classification system. Taxonomists document the attributes (characters) of organisms, with emphasis on those can be used to distinguish species from each other. Character information is compiled in the scientific literature as text, tables, and images. The information is presented according to conventions that vary among taxonomic domains; such conventions facilitate comparison among similar species, even when descriptions are published by different authors. There is considerable uncertainty within the taxonomic community as to how to re-use images that were included in taxonomic publications, especially in regard to whether copyright applies. This article deals with the principles and application of copyright law, database protection, and protection against unfair competition, as applied to images. We conclude that copyright does not apply to most images in taxonomic literature because they are presented in a standardized way and lack the individuality that is required to qualify as ‘copyrightable works’. There are exceptions, such as wildlife photographs, drawings and artwork produced in a distinctive individual form and intended for other than comparative purposes (such as visual art). Further exceptions may apply to collections of images that qualify as a database in the sense of European database protection law. In a few European countries, there is legal protection for photographs that do not qualify as works in the usual sense of copyright. It follows that most images found in taxonomic literature can be re-used for research or many other purposes without seeking permission, regardless of any copyright declaration. In observance of ethical and scholarly standards, re-users are expected to cite the author and original source of any image that they use

    Cognitive impairment in children and adolescents with migraine

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    INTRODUCTION The presence and characteristics of cognitive alterations in children and adolescents affected by migraine have been largely under-investigated. Childhood and adolescence are key periods for personal growth and academic achievements, and migraine-related cognitive deficits may interfere with functioning levels across several settings. A careful analysis of cognitive impairment in the context of migraine is pivotal for making informed decisions on the most appropriate care pathways. METHODS We therefore critically evaluated the results of research studies conducted to date on cognitive function in children and adolescents affected by migraine using the Pubmed database. The literature search was limited to original articles published in English language and focused on current research trends. We operationally defined cognitive processing as the range of individual cognitive functions assessed by neuropsychological studies. Our analysis, which did not include findings on cognitive processing assessed by neurophysiological measures for methodological consistency, led us to formulate the opinion that young patients affected by migraine may present with specific cognitive deficits. RESULTS An early neuropsychological study on young patients with migraine was conducted in 1989 on a group of 20 children affected by migraine without aura, aged between 7 and 11. The authors of this study did not identify clinically relevant impairment in cognitive performance, with the exception of impaired functioning in short and long-term memory tasks (1). A few years later, Haverkamp et al. (2) reported no significant differences between children with migraine aged 6–12 years and their healthy siblings on a measure of sequential and simultaneous information processing (2). Contrarily, Riva et al. (3) reported significant alterations in the information processing rate only. Patients with migraine showed delayed reaction times to visual stimuli compared to healthy controls; interestingly, reaction times were the only parameters showing a significant correlation with the pattern of headache episodes. The authors hypothesized the existence of reduced rates of information processing speed within the posterior cortical areas involved in detecting visual stimuli and within the premotor areas responsible for programming and implementing motor responses. The findings of this study were however limited by the absence of a matched control group (3)

    Anabolic steroids purchased on the Internet as a cause of prolonged hypogonadotropic hypogonadism

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    OBJECTIVE: To report a case of hypogonadotropic hypogonadism due to the chronic abuse of anabolic steroids purchased over the Internet. DESIGN: Case report. SETTING: Endocrinology unit of the University of Brescia. PATIENT(S): A 34-year-old man. INTERVENTION(S): A single dose (100 μg) of triptorelin (triptorelin test). MAIN OUTCOME MEASURE(S): Clinical symptoms, androgen normalization, levels of serum testosterone, follicle-stimulating hormone, and luteinizing hormone. RESULT(S): Within 1 month, the patient's serum testosterone was in the normal range, and he reported a return to normal energy and libido. CONCLUSION(S): The World Anti-Doping Code has proved to be a very powerful and effective tool in the harmonization of antidoping efforts worldwide, but it is insufficient to combat this illegal phenomenon. To tackle the serious side effects caused by doping we believe that it is necessary to increase monitoring and adopt severe sanctions, particularly with regard to Internet sites
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