341 research outputs found

    Electromagnetic Transients on Power Plant Connection Caused by Lightning Event

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    Lightning events can seriously damage the power systems and they represent one of the most dangerous causes of faults in the transmission lines. Usually, when one want to analyze such effects it is necessary to rely on approximate models or to simplify in some ways the power system. As a consequence, an overall analysis taking into account the complexity of the power system is difficult to find. This paper presents the study of the electromagnetic transients caused by lightning events in a point of connection between a real power plant and a large power grid. The analysis is achieved with a high level of details of the power system and the simulations are obtained through an EMT-type software (PSCAD-EMTDC). Different simulations are analyzed, showing how the cables and the transformers are affected by the electromagnetic transients

    The effects of robotic assistance on upper limb spatial muscle synergies in healthy people during planar upper-limb training

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    Background Robotic rehabilitation is a commonly adopted technique used to restore motor functionality of neurological patients. However, despite promising results were achieved, the effects of human-robot interaction on human motor control and the recovery mechanisms induced with robot assistance can be further investigated even on healthy subjects before translating to clinical practice. In this study, we adopt a standard paradigm for upper-limb rehabilitation (a planar device with assistive control) with linear and challenging curvilinear trajectories to investigate the effect of the assistance in human-robot interaction in healthy people. Methods Ten healthy subjects were instructed to perform a large set of radial and curvilinear movements in two interaction modes: 1) free movement (subjects hold the robot handle with no assistance) and 2) assisted movement (with a force tunnel assistance paradigm). Kinematics and EMGs from representative upper-limb muscles were recorded to extract phasic muscle synergies. The free and assisted interaction modes were compared assessing the level of assistance, error, and muscle synergy comparison between the two interaction modes. Results It was found that in free movement error magnitude is higher than with assistance, proving that task complexity required assistance also on healthy controls. Moreover, curvilinear tasks require more assistance than standard radial paths and error is higher. Interestingly, while assistance improved task performance, we found only a slight modification of phasic synergies when comparing assisted and free movement. Conclusions We found that on healthy people, the effect of assistance was significant on task performance, but limited on muscle synergies. The findings of this study can find applications for assessing human-robot interaction and to design training to maximize motor recovery

    Lightning activity in the Southern Coast of Chile

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    Ponencia presentada en la XV International Conference on Atmospheric Electricity, 15-20 June 2014, Norman, Oklahoma, U.S.A.Based on eight years of lightning data (from January 2005 to December 2012) from the World Wide Lightning Location Network (WWLLN) we describe the spatial distribution and temporal variability of lightning activity over southern Chile. This region extends from ~ 40°S to 55°S along the west coast of South America, is limited to the east by the austral Andes about 100 km inland, and features a maritime climate with annual mean precipitation in excess of 4000 mm. Cloud electrification is not expected in this region given the predominance of stable, deep-stratiform precipitation there, but days with at least one stroke occur up to a third of the time along the coast, being slightly more frequent during late summer and fall. Lightning density and frequency of lightning days exhibit a sharp maximum along the coast of southern Chile. Disperse strokes are also observed off southern Chile. In contrast, lightning activity is virtually inexistent over the austral Andes -where precipitation is maximum- and farther east over the dry lowlands of Argentina. It is suggested that electrification could develop under weakly unstable conditions that prevail in the region after the passage of a cold front. Large-scale ascent near the cyclone?s center may lift near-surface air parcels over open ocean fostering shallow convection, which is enhanced as the strong westerly flow ascend over the coastal topography. Laboratory experiments of charge transferred during ice crystal-graupel collisions in low liquid water content conditions and low impact velocity have shown that the non-inductive mechanism can work as a charge separation process in these systems.Fil: Nicora, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Nicora, M. Gabriela. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Quel, Eduardo J. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Quel, Eduardo J. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Departamento de Investigaciones en Láseres y sus aplicaciones; Argentina.Fil: Bürgesser, Rodrigo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Bürgesser, Rodrigo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Ávila, Eldo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Ávila, Eldo E. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Garreaud, René D. Universidad de Chile. Department of Geophysics; ChileFil: Garreaud, René D. Center for Climate and Resilience Research; ChileInvestigación Climatológic

    Magnetostratigraphy and biostratigraphy of the Carnian/Norian boundary interval from the Pizzo Mondello section (Sicani Mountains, Sicily)

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    The 146.5 m-thick Upper Triassic limestone section at Pizzo Mondello in the Sicani Mountains of western Sicily is characterized by high quality of exposure, accessibility, and stratigraphic continuity. Magnetostratigraphic results delineate 12 normal and reverse polarity magnetozones, labelled successively from the base upwards as PM1n, PM1r, PM6n, PM6r. The Carnian/Norian boundary, based on conodont biostratigraphy, falls somewhere in the PM3n to PM5n interval which corresponds to the E14n to E16n magnetozone interval in the Newark reference sequence of polarity reversals. Comparison of magnetobiostratigraphic data from the Newark basin, Pizzo Mondello and other Late Triassic marine sections available from the literature suggests the existence of a reduction in sedimentation rate in the Tethyan marine domain at around the Carnian/Norian boundary. Although the Newark and the expanded Pizzo Mondello sections correlate well with each other, correlation with the condensed Kavur Tepe and Scheiblkogel sections is unsatisfactory. A re-interpretation of the Kavur Tepe results suggests that the section is younger than its previous correlation with the Newark section, and that it was deposited in the northern instead of the southern hemisphere. Most of the condensed Tethyan marine sections are seen to be highly discontinuous, as evidenced by concantenated conodont total range zones

    Urinary virome perturbations in kidney transplantation

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    The human microbiome is important for health and plays a role in essential metabolic functions and protection from certain pathogens. Conversely, dysbiosis of the microbiome is seen in the context of various diseases. Recent studies have highlighted that a complex microbial community containing hundreds of bacteria colonizes the healthy urinary tract, but little is known about the human urinary viruses in health and disease. To evaluate the human urinary virome in the context of kidney transplantation (tx), variations in the composition of the urinary virome were evaluated in urine samples from normal healthy volunteers as well as patients with kidney disease after they had undergone kidney tx. Liquid chromatography-mass spectrometry/mass spectrometry analysis was undertaken on a selected cohort of 142 kidney tx patients and normal healthy controls, from a larger biobank of 770 kidney biopsy matched urine samples. In addition to analysis of normal healthy control urine, the cohort of kidney tx patients had biopsy confirmed phenotype classification, coincident with the urine sample analyzed, of stable grafts (STA), acute rejection, BK virus nephritis, and chronic allograft nephropathy. We identified 37 unique viruses, 29 of which are being identified for the first time in human urine samples. The composition of the human urinary virome differs in health and kidney injury, and the distribution of viral proteins in the urinary tract may be further impacted by IS exposure, diet and environmental, dietary, or cutaneous exposure to various insecticides and pesticides

    Pain in cancer. An outcome research project to evaluate the epidemiology, the quality and the effects of pain treatment in cancer patients

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    BACKGROUND: Management of pain related to advanced or metastatic cancer, although the availability of several pharmacological and non-pharmacological interventions and the existence of well-known guidelines and protocols, is often difficult and inadequate. Evidence of the relative effectiveness of current options for treating cancer pain from comparative randomized studies is scanty. METHODS: In the context of a wider project, a multicenter, open label, prospective Outcome Research study will be launched in Italy in 2006 to investigate the epidemiology of cancer pain and of its treatments, the quality of analgesic-drug therapy and the effectiveness of alternative analgesic strategies in a large, prospective, unselected cohort of cancer patients using the state-of-the art of patient-reported-outcomes. About 100 Italian centers will recruit 2500 patients with advanced/progressive/metastatic cancer with pain (related to the cancer disease) requiring analgesic treatments. Each center is expected to recruit 25 consecutive and eligible patients during the study inception period. Approximately two months will be allowed for subject recruitment and enrollment. Subject evaluation and follow-up will be for 3 months. The effect on outcomes of various therapeutic analgesic options administered by physicians, given the observational approach where patients are not assigned at random to different treatments, will be compared using the propensity score approach, allowing the adjustment for treatment selection bias. Later, after the launch of the observational study and on the basis of results, in specific subsamples of patients and in select centers of the network, a Randomized Controlled Trial will be carried out to formally compare the efficacy of alternative analgesic strategies, with particular emphasis on oral morphine (as comparator) and buprenorphine patch (as experimental arm). Results from the outcome (cohort) and experimental (Randomized Controlled Trial) studies will ensure both the external and internal validity

    Perturbations in the Urinary Exosome in Transplant Rejection

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    Urine exosomes are small vesicles exocytosed into the urine by all renal epithelial cell types under normal physiologic and disease states. Urine exosomal proteins may mirror disease specific proteome perturbations in kidney injury. Analysis methodologies for the exosomal fraction of the urinary proteome were developed for comparing the urinary exosomal fraction versus unfractionated proteome for biomarker discovery. Urine exosomes were isolated by centrifugal filtration of urine samples collected from kidney transplant patients with and without acute rejection, which were biopsy matched. The proteomes of unfractionated whole urine (Uw) and urine exosomes (Ue) underwent mass spectroscopy-based quantitative proteonomics analysis. The proteome data were analyzed for significant differential protein abundances in acute rejection (AR). A total of 1018 proteins were identified in Uw and 349 proteins in Ue. 279 overlapped between the two urinary compartments and 70 proteins were unique to the Ue compartment. Of 349 exosomal proteins identified from transplant patients,220 had not been previously identified in the normal Ue fraction. 11 Ue proteins, functionally involved in an inflammatory and stress response, were more abundant in urine samples from patients with acute rejection, 3 of which are exclusive to the Ue fraction. Ue AR-specific biomarkers(8) were also detected in Uw, but since they were observed at significantly lower abundances in Uw, they were not significant for AR in Uw. A rapid urinary exosome isolation method and quantitative measurement of enriched Ue proteins was applied. Perturbed proteins in the exosomal compartment of urine collected from kidney transplant patients were specific to inflammatory responses, and were not observed in the Ue fraction from normal healthy subjects. Ue specific protein alterations in renal disease provide potential mechanistic insights and offer a unique panel of sensitive biomarkers for monitoring AR

    Magnetostratigraphy and Biostratigraphy of the Carnian/Norian Boundary Interval from the Pizzo Mondello Section (Sicily)

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    We present new magnetostratigraphic and biostratigraphic data from an Upper Triassic limestone section named Pizzo Mondello. This section is 141m-thick and crops out in the Sicani Mountains of western Sicily (Italy). The Pizzo Mondello section is one of the Tethyan best in virtue of its high quality of exposure, accessibility, stratigraphic continuity and good magnetostratigraphic data. We recognize a sequence of six magnetozones, from M1 to M6, each subdivided into a lower predominantly normal and an upper predominantly reversed magnetozone. This sequence of magnetozones spans the Carnian/Norian boundary according to conodont biostratigraphy. The Carnian/Norian boundary should fall in the upper part of magnetozone M3 which should correspond to chron E14 in the Newark reference sequence of polarity reversals. The comparison of data from the Newark basin, Pizzo Mondello and the Late Triassic Bolcektasi Tepe section from the literature seems to suggest the existence of a disconformity in the Tethyan marine domain at around the Carnian/Norian boundary which we tentatively relate to intraPangea tectonic mobility. A consistent correlation of Newark/Pizzo Mondello with published data from the Norian Tethyan marine Kavur Tepe and Scheiblkogel sections is still elusive, suggesting that the validity of the original polarity interpretation of the Kavur Tepe section could usefully be critically reviewed

    Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1

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    Lignocellulosic biofuels are promising as sustainable alternative fuels, but lignin inhibits access of enzymes to cellulose, and by-products of lignin degradation can be toxic to cells. The fast growth, high efficiency and specificity of enzymes employed in the anaerobic litter deconstruction carried out by tropical soil bacteria make these organisms useful templates for improving biofuel production. The facultative anaerobe Enterobacter lignolyticus SCF1 was initially cultivated from Cloud Forest soils in the Luquillo Experimental Forest in Puerto Rico, based on anaerobic growth on lignin as sole carbon source. The source of the isolate was tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, where bacteria using oxygen-independent enzymes likely play an important role in decomposition. We have used transcriptomics and proteomics to examine the observed increased growth of SCF1 grown on media amended with lignin compared to unamended growth. Proteomics suggested accelerated xylose uptake and metabolism under lignin-amended growth, with up-regulation of proteins involved in lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase (GST) proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. This suggested the use of lignin as terminal electron acceptor. We detected significant lignin degradation over time by absorbance, and also used metabolomics to demonstrate moderately significant decreased xylose concentrations as well as increased metabolic products acetate and formate in stationary phase in lignin-amended compared to unamended growth conditions. Our data show the advantages of a multi-omics approach toward providing insights as to how lignin may be used in nature by microorganisms coping with poor carbon availability
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