1,288 research outputs found

    Improving Software Quality Through the Use of Statistics: An Initial Approach

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    Information systems development is a very important activity that is performed continuously in Information Systems departments. We can say that quality is a complex measurement of a product or service that people demands. However, quality is a measurement that is composed by a set of aspects. Quality measurement can be performed in concrete or abstract form. Software quality is a very important issue that developers must address properly, but a lot has to do with abstract aspects of it nonetheless. We proposed an approach that could reduce the abstractness of software quality measurement. In order to prove it, we conducted a study with encouraging results. We found that end-user participation in the evaluation IS quality can be improved

    IR and electrochemical synthesis and characterization of thin films of PEDOT grown on platinum single crystal electrodes in [EMMIM]Tf2N ionic liquid

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    Thin films of PEDOT synthesized on platinum single electrodes in contact with the ionic liquid 1-ethyl-2,3-dimethylimidazolium triflimide ([EMMIM]Tf2N) were studied by cyclic voltammetry, chronoamperometry, infrared spectroscopy and atomic force microscopy. It was found that the polymer grows faster on Pt(111) than on Pt(110) or Pt(100) and that the redox reactions associated with the PEDOT p-doping process are much more reversible in [EMMIM]Tf2N than in acetonitrile. Finally, the ion exchange and charge carriers’ formation during the p-doping reaction of PEDOT were studied using in situ FTIR spectroscopy.APS acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the “Universidad Nacional de Colombia (UNAL)” and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges support of UNAL (Research Project 19030). JMF thanks MINECO (Spain) support through project CTQ2013-44083-P and Generalitat Valenciana (Feder) through project PROMETEOII/2014/013

    Hydrogen redox reactions in 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide on platinum single crystal electrodes

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    Hydrogen oxidation and the subsequent proton reduction are studied on platinum single crystal electrodes in purified 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid. The hydrogen redox reaction shows some dependence of the surface orientation. The highest reversibility is observed with Pt(111) whereas the reaction in electrodes with {100} sites is less reversible and with a slow kinetics. Adsorption states are observed in the presence of hydrogen along with the main oxidation reaction. Also, it is possible to detect protons after oxidation of water and H2O2.APS is grateful to the National University of Colombia (ESP-2011-02) for the scholarship “Estudiantes sobresalientes de posgrado”, and to COLCIENCIAS (567-2012) for the national doctoral scholarship. MFS acknowledges support from the National University of Colombia (Research Project 19030). JMF acknowledges support from Generalitat Valenciana (Feder) (PROMETEO/2009/045) through project PROMETEO/2009/045

    Study of the interface Pt(111)/ [Emmim][NTf2] using laser-induced temperature jump experiments

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    The interface between a Pt(111) electrode and a room temperature ionic liquid, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, was investigated with the laser-induced temperature jump method. In this technique, the temperature of the interface is suddenly increased by applying short laser pulses. The change of the electrode potential caused by the thermal perturbation is measured under coulostatic conditions during the subsequent temperature relaxation. This change is mainly related to the reorganization of the solvent components near the electrode surface. The sign of the potential transient depends on the potential of the experiment. At high potential values, positive transients indicate a higher density of anions than cations close the surface, contributing negatively to the potential of the electrode. Decreasing the applied potential to sufficiently low values, the transient becomes negative, meaning that the density of cations becomes then higher at the surface of the electrode. The potential dependence of the interfacial response shows a marked hysteresis depending on the direction in which the applied potential is changed.Support from MINECO (Spain) through project CTQ2013-44083-P is greatly acknowledged. Paula Sebastian acknowledges to the Generalitat valenciana for the award of vali + d gran

    Interaction of water with methanesulfonic acid on Pt single crystal electrodes

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    The electrochemical behavior of methanesulfonic acid on platinum single crystal electrode surfaces is investigated by cyclic voltammetry and infrared spectroscopy measurements. The results are compared with the voltammetric profiles of perchloric and trifluoromethanesulfonic acids. The differences are interpreted in terms of the effect of the anion on the structure of water. No adsorbed species are detected by infrared spectroscopy.APS acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the UNC and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges the support of UNC (Research Project 19030). JMFwould like to thankGeneralitat Valenciana (Feder) through project PROMETEOII/2014/013

    Resultados del tratamiento quirĂșrgico de los aneurismas de aorta abdominal infrarrenal

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    Introduction: Surgical treatment outcomes for infrarenal abdominal aortic aneurysm repair depend on patient factors and attending vascular team expertise. Objetives: To describe the outcomes of surgical treatment of abdominal aortic aneurysm performed by an interdisciplinary team and to evaluate the effects of annual caseload and acquired expertise. Methods: Historic cohort of patients with abdominal aortic aneurysm diagnosis surgically trea-ted from January 1994 to June 2013. Three groups were established: Group 1 was for openruptured abdominal aortic aneurysm repair, Group 2 was for open elective repair and Group 3 was for elective endovascular aneurysm repairs. Primary outcome was in-hospital mortality, andsecondary outcomes were peri-procedural morbidity. For analysis the cohort was divided in two: cases repaired from 1994 to 2002 and from 2002 to 2013. This was based in the implementation of endovascular therapy from 2002 at the institution.Results: 573 patients were treated; Group 1: 65 patients; Group 2: 433 patients; Group 3: 75 patients. Mortality was 28.6%, 2.8% and 1.3% respectively. A significant rise in annual case-load (233%) was demonstrated and a trend toward lowering in surgical mortality (4.8 vs. 2.0%,p = 0.19) after 2002. Conclusions: Implementation of endovascular repair has contributed to rising annual caseloadof patients with abdominal aortic aneurysm at our institution. This rising in volume correlateswith effective lowering in mortality. © 2015 Sociedad Colombiana de Cardiología y Cirugía Cardiovascular

    Urinary Incontinence and Health-Seeking Behavior Among White, Black, and Latina Women

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    Fewer than half of women with urinary incontinence (UI) seek care for their condition. Our objective was to qualitatively assess themes surrounding treatment seeking behaviors

    Role of the interfacial water structure on electrocatalysis: Oxygen reduction on Pt(1 1 1) in methanesulfonic acid

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    Most of electrocatalytic reactions occur in an aqueous environment. Understanding the influence of water structure on reaction dynamics is fundamental in electrocatalysis. In this work, the role of liquid water structure on the oxygen reduction at Pt(1 1 1) electrode is analyzed in methanesulfonic (MTSA) and perchloric acids. This is because these different anions can exert a different influence on liquid water structure. Results reveal a lower ORR electrode activity in MTSA than in HClO4 solutions and they are discussed in light of anion's influence on water structural ordering. From them, the existence of an outer-sphere, rate determining, step in the ORR mechanism is suggested.This work has been carried out under MINECO project CTQ2013-44083-P (Spain). APSR acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the UNAL and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges the support of UNAL (Research Project 19030)

    Factores asociados a insuficiencia renal postoperatoria en cirugĂ­a de revascularizaciĂłn miocĂĄrdica

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    Motivation: To determine which medical history and surgical procedure factors are associated to the onset of postoperative kidney failure in patients undergoing myocardial revascularisation. Methods: Case-control cohort study carried out between January 2005 and December 2013 which included patients who had undergone elective myocardial revascularisation and showed postoperative kidney failure immediately after surgery and until discharge. Controls consisted of patients who had undergone elective myocardial revascularisation and did not develop postoperative kidney failure immediately after surgery. A logistic regression model was used to determine the factors associated to postoperative kidney failure. Associations were expressed as grounds of disparity with their corresponding confidence intervals. Results: old age [OR 1.03 CI 95% (1.01-1.04)], preoperative presence of diabetes mellitus [OR 1.8 CI 95% (1.9-3.4)], cardiac insufficiency [OR 2.7 CI 95% (1.1-6.7)] and a longer perfusion time [OR 1.02 CI 95% (1.01-1.03)] were associated to a higher risk of postoperative kidney failure, while higher hematocrit [OR 0.86 CI 95% (0.82-0.91)] and higher ejection fraction [OR 0.94 CI 95% (0.92-0.96)] were associated with a decrease of the risk of postoperative kidney failure. Conclusions: In patients who had undergone myocardial revascularisation, risk factors associated to postoperative kidney failure where comorbidities related to internal and external gradual kidney damage outside the context of the surgery. This implies that strategies to minimise this event should be focused on identifying these patients in a timely manner and offering appropriate nephroprotection. © 2015 Sociedad Colombiana de Cardiología y Cirugía Cardiovascular

    The Escherichia coli BtuE Protein Functions as a Resistance Determinant against Reactive Oxygen Species

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    This work shows that the recently described Escherichia coli BtuE peroxidase protects the bacterium against oxidative stress that is generated by tellurite and by other reactive oxygen species elicitors (ROS). Cells lacking btuE (ΔbtuE) displayed higher sensitivity to K2TeO3 and other oxidative stress-generating agents than did the isogenic, parental, wild-type strain. They also exhibited increased levels of cytoplasmic reactive oxygen species, oxidized proteins, thiobarbituric acid reactive substances, and lipoperoxides. E. coli ΔbtuE that was exposed to tellurite or H2O2 did not show growth changes relative to wild type cells either in aerobic or anaerobic conditions. Nevertheless, the elimination of btuE from cells deficient in catalases/peroxidases (Hpx−) resulted in impaired growth and resistance to these toxicants only in aerobic conditions, suggesting that BtuE is involved in the defense against oxidative damage. Genetic complementation of E. coli ΔbtuE restored toxicant resistance to levels exhibited by the wild type strain. As expected, btuE overexpression resulted in decreased amounts of oxidative damage products as well as in lower transcriptional levels of the oxidative stress-induced genes ibpA, soxS and katG
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