411 research outputs found

    The Role of the Random Magnetic Fields in the ISM: HVCs Numerical Simulations

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    We know that the galactic magnetic field possesses a random component in addition to the mean uniform component, with comparable strength of the two components. This random component is considered to play important roles in the evolution of the interstellar medium (ISM). In this work we present numerical simulations associated with the interaction of the supersonic flows located at high latitude in our Galaxy (High Velocity Clouds, HVC) with the magnetized galactic ISM in order to study the effect that produces a random magnetic field in the evolution of this objects.Comment: 2 pages, 1 figure. To appear in Proceedings IAU Symposium No. 259. Cosmic Magnetic Fields: From Planets, to Stars and Galaxies (in press

    Validation of a Computational Fluid Dynamics Model for a Novel Residence Time Distribution Analysis in Mixing at Cross-Junctions

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    [EN] In Water Distribution Networks, the chlorine control is feasible with the use of water quality simulation codes. EPANET is a broad domain software and several commercial computer software packages base their models on its methodology. However, EPANET assumes that the solute mixing at cross-junctions is ¿complete and instantaneous¿. Several authors have questioned this model. In this paper, experimental tests are developed while using Copper Sulphate as tracer at different operating conditions, like those of real water distribution networks, in order to obtain the Residence Time Distribution and its behavior in the mixing as a novel analysis for the cross-junctions. Validation tests are developed in Computational Fluid Dynamics, following the k-# turbulence model. It is verified that the mixing phenomenon is dominated by convection, analyzing variation of Turbulent Schmidt Number vs. experimental tests. Having more accurate mixing models will improve the water quality simulations to have an appropriate control for chlorine and possible contaminants in water distribution networks.To CONACYT for the Master and Ph.D. scholarships (417824 and 703220) to D.H.-C. and the Ph.D. scholarship (294038) to M.R.; To Universidad de Guanajuato for the financial support of the project No. 100/2018 of J.L.N.; To Engineering Division, Campus Guanajuato and Geomatics and Hydraulics Engineering Department for the financial support of this project; and finally, to SEP-PRODEP and UG for the financial support to publish this paper.Hernandez Cervantes, D.; Delgado Galván, XV.; Nava, JL.; López Jiménez, PA.; Rosales, M.; Mora Rodríguez, JDJ. (2018). Validation of a Computational Fluid Dynamics Model for a Novel Residence Time Distribution Analysis in Mixing at Cross-Junctions. Water. 10(6):1-18. https://doi.org/10.3390/w10060733S118106Mercier Shanks, C., Sérodes, J.-B., & Rodriguez, M. J. (2013). Spatio-temporal variability of non-regulated disinfection by-products within a drinking water distribution network. Water Research, 47(9), 3231-3243. doi:10.1016/j.watres.2013.03.033Vasconcelos, J. J., Rossman, L. A., Grayman, W. M., Boulos, P. F., & Clark, R. M. (1997). Kinetics of chlorine decay. Journal - American Water Works Association, 89(7), 54-65. doi:10.1002/j.1551-8833.1997.tb08259.xOzdemir, O. N., & Ucak, A. (2002). Simulation of Chlorine Decay in Drinking-Water Distribution Systems. Journal of Environmental Engineering, 128(1), 31-39. doi:10.1061/(asce)0733-9372(2002)128:1(31)Knobelsdorf Miranda, J., & Mujeriego Sahuquillo, R. (1997). Crecimiento bacteriano en las redes de distribución de agua potable: una revisión bibliográfica. Ingeniería del agua, 4(2). doi:10.4995/ia.1997.2719Wang, W., Ye, B., Yang, L., Li, Y., & Wang, Y. (2007). Risk assessment on disinfection by-products of drinking water of different water sources and disinfection processes. Environment International, 33(2), 219-225. doi:10.1016/j.envint.2006.09.009Parks, S. L. I., & VanBriesen, J. M. (2009). Booster Disinfection for Response to Contamination in a Drinking Water Distribution System. Journal of Water Resources Planning and Management, 135(6), 502-511. doi:10.1061/(asce)0733-9496(2009)135:6(502)Hernández Cervantes, D., Mora Rodríguez, J., Delgado Galván, X., Ortiz Medel, J., & Jiménez Magaña, M. R. (2015). Optimal use of chlorine in water distribution networks based on specific locations of booster chlorination: analyzing conditions in Mexico. Water Supply, 16(2), 493-505. doi:10.2166/ws.2015.161Weickgenannt, M., Kapelan, Z., Blokker, M., & Savic, D. A. (2010). Risk-Based Sensor Placement for Contaminant Detection in Water Distribution Systems. Journal of Water Resources Planning and Management, 136(6), 629-636. doi:10.1061/(asce)wr.1943-5452.0000073Rathi, S., & Gupta, R. (2013). Monitoring stations in water distribution systems to detect contamination events. ISH Journal of Hydraulic Engineering, 20(2), 142-150. doi:10.1080/09715010.2013.857470Seth, A., Klise, K. A., Siirola, J. D., Haxton, T., & Laird, C. D. (2016). Testing Contamination Source Identification Methods for Water Distribution Networks. Journal of Water Resources Planning and Management, 142(4), 04016001. doi:10.1061/(asce)wr.1943-5452.0000619Xuesong, Y., Jie, S., & Chengyu, H. (2017). Research on contaminant sources identification of uncertainty water demand using genetic algorithm. Cluster Computing, 20(2), 1007-1016. doi:10.1007/s10586-017-0787-6Rathi, S., & Gupta, R. (2015). Optimal sensor locations for contamination detection in pressure-deficient water distribution networks using genetic algorithm. Urban Water Journal, 14(2), 160-172. doi:10.1080/1573062x.2015.1080736Sandoval, M. A., Fuentes, R., Walsh, F. C., Nava, J. L., & de León, C. P. (2016). Computational fluid dynamics simulations of single-phase flow in a filter-press flow reactor having a stack of three cells. Electrochimica Acta, 216, 490-498. doi:10.1016/j.electacta.2016.09.045Castañeda, L. (2017). Computational Fluid Dynamic Simulations of Single-Phase Flow in a Spacer-Filled Channel of a Filter-Press Electrolyzer. International Journal of Electrochemical Science, 7351-7364. doi:10.20964/2017.08.09Song, I., Romero-Gomez, P., & Choi, C. Y. (2009). Experimental Verification of Incomplete Solute Mixing in a Pressurized Pipe Network with Multiple Cross Junctions. Journal of Hydraulic Engineering, 135(11), 1005-1011. doi:10.1061/(asce)hy.1943-7900.0000095Romero-Gomez, P., Lansey, K. E., & Choi, C. Y. (2010). Impact of an incomplete solute mixing model on sensor network design. Journal of Hydroinformatics, 13(4), 642-651. doi:10.2166/hydro.2010.123Yu, T. C., Shao, Y., & Shen, C. (2014). Mixing at Cross Joints with Different Pipe Sizes in Water Distribution Systems. Journal of Water Resources Planning and Management, 140(5), 658-665. doi:10.1061/(asce)wr.1943-5452.0000372Shao, Y., Jeffrey Yang, Y., Jiang, L., Yu, T., & Shen, C. (2014). Experimental testing and modeling analysis of solute mixing at water distribution pipe junctions. Water Research, 56, 133-147. doi:10.1016/j.watres.2014.02.053Mompremier, R., Pelletier, G., Fuentes Mariles, Ó. A., & Ghebremichael, K. (2015). Impact of incomplete mixing in the prediction of chlorine residuals in municipal water distribution systems. Journal of Water Supply: Research and Technology - Aqua, 64(8), 904-914. doi:10.2166/aqua.2015.148McKenna, S. A., O’Hern, T., & Hartenberger, J. (2009). Detailed Investigation of Solute Mixing in Pipe Joints through High Speed Photography. Water Distribution Systems Analysis 2008. doi:10.1061/41024(340)88Ho, C. K., & O’Rear, L. (2009). Evaluation of solute mixing in water distribution pipe junctions. Journal - American Water Works Association, 101(9), 116-127. doi:10.1002/j.1551-8833.2009.tb09964.xChoi, C. Y., Shen, J. Y., & Austin, R. G. (2009). Development of a Comprehensive Solute Mixing Model (AZRED) for Double-Tee, Cross, and Wye Junctions. Water Distribution Systems Analysis 2008. doi:10.1061/41024(340)89Rosales, M., Pérez, T., & Nava, J. L. (2016). Computational fluid dynamic simulations of turbulent flow in a rotating cylinder electrode reactor in continuous mode of operation. Electrochimica Acta, 194, 338-345. doi:10.1016/j.electacta.2016.02.076Moncho-Esteve, I. J., Palau-Salvador, G., Brevis, W., Vaas, M. O., & López-Jiménez, P. A. (2015). Numerical simulation of the hydrodynamics and turbulent mixing process in a drinking water storage tank. Journal of Hydraulic Research, 53(2), 207-217. doi:10.1080/00221686.2014.98945

    Grade V small bowel injury after blunt abdominal trauma: a case report

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    Injury of the small intestine or mesentery that requires surgical intervention is relatively uncommon, presenting less than 1% of all trauma. Unstable hemodynamically patients with peritoneal irritation signs and stable hemodynamically patients with radiological signs of intestine or mesentery lesions need an exploratory laparotomy. A 33-year-old male patient, suffered a car accident in which he had a frontal impact collision and was between two structures for 30 minutes, and rescued by the fire department. Physical examination of the abdomen presents generalized pain on palpation of moderate intensity and rebound sign. An exploratory laparotomy was performed, the findings were: hemoperitoneum of 1500 ml was found, lesion in the bucket loop of 1.2 meters, 1.8 meters from the Treitz angle and 70 cm from the ileocecal valve. We managed with drainage, vascular control, resection of the devascularized intestinal loop and small bowel shotgun stoma were. The patient was transferred to the intensive care unit for hemodynamic management and a second look was performed 5 days after surgery where cavity lavage, stoma dismantling and end-to-end anastomosis of the small intestine in two planes were performed. On post-operative day 7 drains were removed, and the patient was discharged from the surgical service due to improvement, without complications. We recommend a multidisciplinary approach to patients with polytrauma, since they lead to a better and faster recovery, in the same way it allows us to detect and treat any abnormality that impacts the quality of life of patients early

    Inverse Association between Dietary Iron Intake and Gastric Cancer: A Pooled Analysis of Case‐Control Studies of the Stop Consortium

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    Background: Inconsistent findings have been reported regarding the relationship between dietary iron intake and the risk of gastric cancer (GC). Methods: We pooled data from 11 case‐control studies from the Stomach Cancer Pooling (StoP) Project. Total dietary iron intake was derived from food frequency questionnaires combined with national nutritional tables. We derived the odds ratios (ORs) and 95% confidence intervals (CIs) for quartiles of dietary iron through multivariable unconditional logistic regression models. Secondary analyses stratified by sex, smoking status, caloric intake, anatomical subsite and histological type were performed. Results: Among 4658 cases and 12247 controls, dietary iron intake was inversely associated with GC (per quartile OR 0.88; 95% CI: 0.83–0.93). Results were similar between cardia (OR = 0.85, 95% CI = 0.77–0.94) and non‐cardia GC (OR = 0.87, 95% CI = 0.81–0.94), and for diffuse (OR = 0.79, 95% CI = 0.69–0.89) and intestinal type (OR = 0.88, 95% CI = 0.79–0.98). Iron intake exerted an independent effect from that of smoking and salt intake. Additional adjustment by meat and fruit/vegetable intake did not alter the results. Conclusions: Dietary iron is inversely related to GC, with no difference by subsite or histological type. While the results should be interpreted with caution, they provide evidence against a direct effect of iron in gastric carcinogenesis

    VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

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    VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

    Splanchnic vein thrombosis in myeloproliferative neoplasms: risk factors for recurrences in a cohort of 181 patients

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    We retrospectively studied 181 patients with polycythaemia vera (n=67), essential thrombocythaemia (n=67) or primary myelofibrosis (n=47), who presented a first episode of splanchnic vein thrombosis (SVT). Budd-Chiari syndrome (BCS) and portal vein thrombosis were diagnosed in 31 (17.1%) and 109 (60.3%) patients, respectively; isolated thrombosis of the mesenteric or splenic veins was detected in 18 and 23 cases, respectively. After this index event, the patients were followed for 735 patient years (pt-years) and experienced 31 recurrences corresponding to an incidence rate of 4.2 per 100 pt-years. Factors associated with a significantly higher risk of recurrence were BCS (hazard ratio (HR): 3.03), history of previous thrombosis (HR: 3.62), splenomegaly (HR: 2.66) and leukocytosis (HR: 2.8). Vitamin K-antagonists (VKA) were prescribed in 85% of patients and the recurrence rate was 3.9 per 100 pt-years, whereas in the small fraction (15%) not receiving VKA more recurrences (7.2 per 100 pt-years) were reported. Intracranial and extracranial major bleeding was recorded mainly in patients on VKA and the corresponding rate was 2.0 per 100 pt-years. In conclusion, despite anticoagulation treatment, the recurrence rate after SVT in myeloproliferative neoplasms is high and suggests the exploration of new avenues of secondary prophylaxis with new antithrombotic drugs and JAK-2 inhibitors

    Chitosan–Starch–Keratin composites: Improving thermo-mechanical and degradation properties through chemical modification

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    The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73 % for chitosan-starch matrix up to 16 % for the composites with 5wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiat-ing chitosan–starch films with sustainable featuresChitosan–starch polymers are reinforced with different keratin materials obtained from chicken feather. Keratin materials are treated with sodium hydroxide; the modified surfaces are rougher in comparison with untreated surfaces, observed by Scanning Electron Microscopy. The results obtained by Differential Scanning Calorimetry show an increase in the endothermic peak related to water evaporation of the films from 92 °C (matrix) up to 102–114 °C (reinforced composites). Glass transition temperature increases from 126 °C in the polymer matrix up to 170–200 °C for the composites. Additionally, the storage modulus in the composites is enhanced up to 1614 % for the composites with modified ground quill, 2522 % for composites with modified long fiber and 3206 % for the composites with modified short fiber. The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73 % for chitosan-starch matrix up to 16 % for the composites with 5wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiat-ing chitosan–starch films with sustainable featuresUniversidad Autónoma del Estado de México Tecnológico Nacional de México, Instituto Tecnológico de Querétaro Universidad Nacional Autónoma de México Tecnológico Nacional de México, Instituto Tecnológico de Celaya Universidad Autónoma de Cd. Juáre

    Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

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    Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range η<0.8|\eta| < 0.8 are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
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