3,777 research outputs found

    Wildfire spreading simulator using fast marching algorithm

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    Programs that can predict wildfire behavior are a very useful tool in terms of extinguishing these fires more effectively. State of the art wildfire simulators present some drawbacks such as not being sufficiently user-friendly, being expensive, requiring great computational power or having poor graphical representation. This paper presents a prototype wildfire simulation app that uses Fast Marching (FM) as its core algorithm. The wildfire app is developed as a Matlab GUI. Said application shows the shape of the fire front at a given moment in time in a 3D map of the terrain affected by the fire. Any real life maps can be loaded to the application for wildfire prediction. The user can choose to vary parameters such as starting (ignition) and ending points, wind direction and speed and propagation time, and see its effect on fire propagation. Interface response to each change in the input is very fast, therefore proving the effciency of the algorithm. Although a prototype, the wildfire basic app is superior to some state of the art simulators regarding certain important features. It can be concluded that Fast Marching is a valid core algorithm for a fire simulator. The way the app is programmed in Matlab confers it flexibility, enabling further specific changes that make it truly competitive against currently used wildfire simulators

    Robot-assisted kidney transplantation with regional hypothermia using grafts with Multiple Vessels After Extracorporeal Vascular Reconstruction: results from the European Association of Urology Robotic Urology Section Working Group

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    Background: Kidney transplantation using grafts with multiple vessels (GMVs) is technically demanding and may be associated with increased risk of complications or suboptimal graft function. To date, no studies have reported on robot-assisted kidney transplantation (RAKT) using GMVs. Objective: To report our experience with RAKT using GMVs from living donors, focusing on technical feasibility and early postoperative outcomes. Design, setting, and participants: We reviewed the multi-institutional, prospectively collected European Association of Urology (EAU) Robotic Urology Section (ERUS)-RAKT database to select consecutive patients undergoing RAKT from living donors using GMVs between July 2015 and January 2018. Patients undergoing RAKT using grafts with single vessels (GSVs) served as controls. In case of GMVs, ex vivo vascular reconstruction techniques were performed during bench surgery according to the case-specific anatomy. Intervention: RAKT with regional hypothermia. Outcome measurements and statistical analysis: Intraoperative outcomes and early (30 d) postoperative complications and functional results were the main study endpoints. Multivariable logistic regression analysis evaluated potential predictors of suboptimal renal function at 1 mo. Results and limitations: Overall, 148 RAKTs were performed during the study period. Of these, 21/148 (14.2%) used GMVs; in all cases, single arterial and venous anastomoses could be performed after vascular reconstruction. Median anastomoses and rewarming times did not differ significantly between the GMV and GSV groups. Total and cold ischemia times were significantly higher in the GMV cohort (112 vs 88 min, p = 0.004 and 50 vs 34 min, p = 0.003, respectively). Overall complication rate and early functional outcomes were similar among the two groups. No major intra-or postoperative complications were recorded in the GMV cohort. At multivariable analysis, use of GMVs was not significantly associated with suboptimal renal function at 1 mo. Small sample size and short follow-up represent the main study limitations. Conclusions: RAKT using GMVs from living donors is technically feasible and achieved favorable perioperative and short-term functional outcomes. Larger studies with longer follow-up are needed to confirm our findings. Patient summary: In this study, we evaluated for the first time in literature the results of RAKT from living donors using kidneys with multiple arteries and veins. We found that, in experienced centers, RAKT using kidneys with multiple vessels is feasible and achieves optimal results in terms of postoperative kidney function with a low number of postoperative complications. (C) 2018 European Association of Urology. Published by Elsevier B.V. All rights reserved

    An algorithm based on the postoperative decrease of albumin (ΔAlb) to anticipate complications after liver surgery

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    International audienceBackground Perioperative decrease of albumin (Delta Alb) appeared as a promising predictor of complications after digestive surgery, but its role after liver surgery remains unclear. This study aimed to analyze whether and how Delta Alb can be used to predict complications after liver surgery. Methods A bicentric retrospective analysis of patients undergoing liver surgery (2010-2016) was performed, following TRIPOD guidelines. The preoperative and postoperative difference of albumin was calculated on POD 0 and defined as Delta Alb. Patients with any missing variable were excluded. The primary endpoint was overall complications according to the Clavien classification. A multiparametric algorithm based on Delta Alb was generated to optimize prediction performance. Results A total of 110 patients were analyzed. At least one complication occurred in 66 (60%) patients. Patients with and without complication showed a Delta Alb of 15.8 vs. 9.5 g/L (p<0.001). Area under ROC curve (AUC) of Delta Alb was 0.75 (p<0.01.). The Delta Alb-based algorithm showed an AUC of 0.84 (p<0.01), significantly improving performance (p=0.03). Multivariable analysis identified Delta Alb as independent predictor of complications (HR, 1.12; 95% CI, 1.01-1.07; p = 0.002). Conclusions Delta Alb appeared as a promising predictor independently associated with the risk of complication after liver surgery. The study presents a novel decision-tree based on Delta Alb to anticipate complications

    Recent GRBs observed with the 1.23m CAHA telescope and the status of its upgrade

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    We report on optical observations of Gamma-Ray Bursts (GRBs) followed up by our collaboration with the 1.23m telescope located at the Calar Alto observatory. The 1.23m telescope is an old facility, currently undergoing upgrades to enable fully autonomous response to GRB alerts. We discuss the current status of the control system upgrade of the 1.23m telescope. The upgrade is being done by the ARAE our group, based on members of IAA (Instituto de Astrofiisica de Andalucia). Currently the ARAE group is responsible to develop the BOOTES network of robotic telescopes based on the Remote Telescope System, 2nd Version (RTS2), which controls the available instruments and interacts with the EPICS database of Calar Alto. Currently the telescope can run fully autonomously or under observer supervision using RTS2. The fast reaction response mode for GRB reaction (typically with response times below 3 minutes from the GRB onset) still needs some development and testing. The telescope is usually operated in legacy interactive mode, with periods of supervised autonomous runs under RTS2. We show the preliminary results of several GRBs followed up with observer intervention during the testing phase of the 1.23m control software upgrade.Comment: 15 pages, 7 figures. Accepted for publication in the Special issue "Robotic Astronomy" of Advances in Astronomy. It includes two iterations with the referee

    Does Satellite Chlorophyll‐a Respond to Southernmost Patagonian Dust? A Multi‐Year, Event‐Based Approach

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    Mineral aerosols may affect global climate indirectly by enhancing net primary productivity (NPP) upon deposition to the oceans and associated atmosphere-to-ocean CO2 flux. This mechanism is hypothesized to have contributed significantly to the last interglacial-to-glacial climatic transition. However, the dust-NPP connection remains contentious for the present-day climate system. We analyze the impact of southernmost Patagonian dust emissions on southwestern Atlantic Ocean continental shelf and proximal open ocean satellite chlorophyll-a concentration. We use the first decadal time series of surface dust mass flux in southern Patagonia, along with in situ visibility data, to model dust emission, transport, and deposition to the ocean. We then perform a dust event-based analysis of chlorophyll-a time series, using a novel approach by which time series are corrected for post-depositional particle advection due to ocean currents. Finally, we performed chemical analysis of iron in dust samples, a key micronutrient limiting phytoplankton biomass in high-nutrient, low-chlorophyll oceans such as offshore of the 200-m isobath off Patagonia. We find no compelling evidence for an influence of dust as an enhancer of phytoplankton biomass either on shelf or proximal open ocean waters of the southwestern Atlantic Ocean. For open ocean waters this is consistent with a lack of source-inherited bioavailable iron in dust samples. Future case studies addressing similar questions should concentrate on dust sources with identified high contents of bioavailable iron, particularly in the Southern Hemisphere where atmospheric processing of iron is weak.Fil: Cosentino, Nicolas Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Ruiz Etcheverry, Laura Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Bia, Gonzalo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Simonella, Lucio Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Coppo, Renata. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Torre, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Saraceno, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Tur, Veronica Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Gaiero, Diego Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

    In search for the sources of plastic marine litter that contaminates the Easter Island Ecoregion

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    Subtropical gyres are the oceanic regions where plastic litter accumulates over long timescales, exposing surrounding oceanic islands to plastic contamination, with potentially severe consequences on marine life. Islands’ exposure to such contaminants, littered over long distances in marine or terrestrial habitats, is due to the ocean currents that can transport plastic over long ranges. Here, this issue is addressed for the Easter Island ecoregion (EIE). High-resolution ocean circulation models are used with a Lagrangian particle-tracking tool to identify the connectivity patterns of the EIE with industrial fishing areas and coastline regions of the Pacific basin. Connectivity patterns for “virtual” particles either floating (such as buoyant macroplastics) or neutrally-buoyant (smaller microplastics) are investigated. We find that the South American shoreline between 20°S and 40°S, and the fishing zone within international waters off Peru (20°S, 80°W) are associated with the highest probability for debris to reach the EIE, with transit times under 2 years. These regions coincide with the most-densely populated coastal region of Chile and the most-intensely fished region in the South Pacific. The findings offer potential for mitigating plastic contamination reaching the EIE through better upstream waste management. Results also highlight the need for international action plans on this important issue

    The systemic lupus erythematosus IRF5 risk haplotype is associated with systemic sclerosis

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    Systemic sclerosis (SSc) is a fibrotic autoimmune disease in which the genetic component plays an important role. One of the strongest SSc association signals outside the human leukocyte antigen (HLA) region corresponds to interferon (IFN) regulatory factor 5 (IRF5), a major regulator of the type I IFN pathway. In this study we aimed to evaluate whether three different haplotypic blocks within this locus, which have been shown to alter the protein function influencing systemic lupus erythematosus (SLE) susceptibility, are involved in SSc susceptibility and clinical phenotypes. For that purpose, we genotyped one representative single-nucleotide polymorphism (SNP) of each block (rs10488631, rs2004640, and rs4728142) in a total of 3,361 SSc patients and 4,012 unaffected controls of Caucasian origin from Spain, Germany, The Netherlands, Italy and United Kingdom. A meta-analysis of the allele frequencies was performed to analyse the overall effect of these IRF5 genetic variants on SSc. Allelic combination and dependency tests were also carried out. The three SNPs showed strong associations with the global disease (rs4728142: P = 1.34×10<sup>−8</sup>, OR = 1.22, CI 95% = 1.14–1.30; rs2004640: P = 4.60×10<sup>−7</sup>, OR = 0.84, CI 95% = 0.78–0.90; rs10488631: P = 7.53×10<sup>−20</sup>, OR = 1.63, CI 95% = 1.47–1.81). However, the association of rs2004640 with SSc was not independent of rs4728142 (conditioned P = 0.598). The haplotype containing the risk alleles (rs4728142*A-rs2004640*T-rs10488631*C: P = 9.04×10<sup>−22</sup>, OR = 1.75, CI 95% = 1.56–1.97) better explained the observed association (likelihood P-value = 1.48×10<sup>−4</sup>), suggesting an additive effect of the three haplotypic blocks. No statistical significance was observed in the comparisons amongst SSc patients with and without the main clinical characteristics. Our data clearly indicate that the SLE risk haplotype also influences SSc predisposition, and that this association is not sub-phenotype-specific

    Robot-assisted Kidney Transplantation: The European Experience.

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    BACKGROUND: Robot-assisted kidney transplantation (RAKT) has recently been introduced to reduce the morbidity of open kidney transplantation (KT). OBJECTIVE: To evaluate perioperative and early postoperative RAKT outcomes. DESIGN, SETTING AND PARTICIPANTS: This was a multicenter prospective observational study of 120 patients who underwent RAKT, predominantly with a living donor kidney, in eight European institutions between July 2015 and May 2017, with minimum follow-up of 1 mo. The robot-assisted surgical steps were transperitoneal dissection of the external iliac vessels, venous/arterial anastomosis, graft retroperitonealization, and ureterovesical anastomosis. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Descriptive analysis of surgical data and their correlations with functional outcomes. RESULTS AND LIMITATIONS: The median operative and vascular suture time was 250 and 38min, respectively. The median estimated blood loss was 150ml. No major intraoperative complications occurred, although two patients needed open conversion. The median postoperative estimated glomerular filtration rate was 21.2, 45.0, 52.6, and 58.0ml/min on postoperative day 1, 3, 7, and 30, respectively. Both early and late graft function were not related to overall operating time or rewarming time. Five cases of delayed graft function (4.2%) were reported. One case (0.8%) of wound infection, three cases (2.5%) of ileus, and four cases of bleeding (3.3%; three of which required blood transfusion), managed conservatively, were observed. One case (0.8%) of deep venous thrombosis, one case (0.8%) of lymphocele, and three cases (2.5%) of transplantectomy due to massive arterial thrombosis were recorded. In five cases (4.2%), surgical exploration was performed for intraperitoneal hematoma. Limitations of the study include selection bias, the lack of an open control group, and failure to report on patient cosmetic satisfaction. CONCLUSIONS: When performed by surgeons with robotic and KT experience, RAKT is safe and reproducible in selected cases and yields excellent graft function. PATIENT SUMMARY: We present the largest reported series on robot-assisted kidney transplantation. Use of a robotic technique can yield low complication rates, rapid recovery, and excellent graft function. Further investigations need to confirm our promising data

    ANÁLISIS MORFOTECTÓNICO EN EL PIEDEMONTE SUROCCIDENTAL DEL ANTEPAIS ANDINO, SIERRAS PAMPEANAS OCCIDENTALES, SAN JUAN, ARGENTINA

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    El retroarco andino, entre los 27°S y 33°S, se caracteriza por ser una de las regiones con mayor sismicidad cortical en el mundo, siendo epicentro de importantes terremotos en el territorio argentino. Esta sismicidad produce una intensa deformación, provocando cambios en la morfología del terreno. En el sector occidental de Sierras Pampeanas Occidentales, en la sierra de la Huerta, se utilizó un SIG para diferenciar unidades geomorfológicas y determinar parámetros cualitativos y cuantitativos que permitieran caracterizar las geoformas identificadas y su relación con la actividad tectónica. La tectónica andina, que afecta la región desde los últimos 5 millones de años, es el principal factor que controla el paisaje de la región. Se diferenciaron tres unidades morfoestucturales y fallamiento con actividad tectónica cuaternaria, presentando abundantes indicadores morfotectónicos, como niveles aluviales dislocados, variación en el diseño y desvío de los ríos, aumento en su grado de incisión, surgentes de agua, abras de viento e inversión del patrón de drenaje, entre otros. El análisis de los indicadores morfotectónicos permitió identificar cómo la deformación disminuye hacia el sur y aumenta de este a oeste. Finalmente, es posible determinar que la deformación continúa activa, modificando el paisaje actual del piedemonte occidental de la sierra de la Huerta
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