Experimental study of linear and nonlinear regimes of density-driven instabilities induced by CO2 dissolution in water

Density driven instabilities produced by CO2 (gas) dissolution in water containing a color indicator were studied in a Hele Shaw cell. The images were analyzed and instability patterns were characterized by mixing zone temporal evolution, dispersion curves, and the growth rate for different CO2 pressures and different color indicator concentrations. The results obtained from an exhaustive analysis of experimental data show that this system has a different behaviour in the linear regime of the instabilities (when the growth rate has a linear dependence with time), from the nonlinear regime at longer times. At short times using a color indicator to see the evolution of the pattern, the images show that the effects of both the color indicator and CO2 pressure are of the same order of magnitude: The growth rates are similar and the wave numbers are in the same range (0?30 cm-1) when the system is unstable. Although in the linear regime the dynamics is affected similarly by the presence of the indicator and CO2 pressure, in the nonlinear regime, the influence of the latter is clearly more pronounced than the effects of the color indicator.Fil: Outeda, Mabel Noemi. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: El Hasi, Claudio Daniel. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: D'onofrio, Alejandro Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; ArgentinaFil: Zalts, Anita. Universidad Nacional de General Sarmiento. Instituto de Ciencias. Área de Química; Argentin

The association between medical students\u27 motivation with learning environment, perceived academic rank, and burnout

Objectives: To assess the correlations between extrinsic and intrinsic motivation, personal growth and quality of life with learning environment perceptions, perceived academic rank and burnout among medical students. Methods: Cross-sectional questionnaires were administered to medical students at three medical schools in Israel, Malaysia, and China, at the end of one academic year. Surveys included demographic data, students\u27 perceived academic rank, two learning environment perceptions scales, and scales for personal growth, goal orientation, burnout and quality of life. Comparative analyses were made to determine the significance of relationships between the outcome measures and control variables, using a series of t-tests. Pearson correlation coefficients were used to test the hypothesis. Results: Sixty-four percent (400/622) of the students responded. Significant correlations were found between: intrinsic motivation (r(398) =.37, p\u3c.001); personal growth (r(398)=.62, p\u3c.001); and quality of life (r(398)= .48, p \u3c.001) with higher learning environment perceptions, intrinsic motivation (r(398)= .21, p\u3c.001); personal growth (r(398) =.21, p\u3c .001); and quality of life (r(398)=.18, p\u3c.001) with perceived academic rank, and negative correlation between personal growth (r(398) =-.38, p\u3c.001); and quality of life (r(398) =-.42, p\u3c.001) with burnout. Conclusions: Intrinsic motivation, personal growth and quality of life are correlated with higher learning environment perceptions and perceived academic rank. Burnout is influenced by personal growth and quality of life. We suggest focusing on motivation profiles before acceptance to medical school and during studies

Remoción de compuestos fenólicos de aguas superficiales y efluentes.

Capítulo de libroEn los últimos años, se ha llamado la atención sobre una serie de compuestos de origen antropogénico –ya sean residuos urbanos, efluentes industriales o agrícolas– que llegan a los cursos de agua superficiales, denominados contaminantes emergentes. Entre los residuos urbanos, un grupo muy importante son los provenientes de productos de cuidado personal, principalmente cosméticos y farmacéuticos.Fil: Beiguel, Érica. ICI-UNGS, Los Polvorines, Argentina. Email: [email protected]: Hughes, Enrique. ICI-UNGS, Los Polvorines, Argentina.Fil: Zalts, Anita. ICI-UNGS, Los Polvorines, Argentina.Fil: Montserrat, Javier. ICI-UNGS, Los Polvorines/CONICET, Argentina

Differential diffusion effects on buoyancy-driven instabilities of acid-base fronts: The case of a color indicator

Buoyancy-driven hydrodynamic instabilities of acid-base fronts are studied both experimentally and theoretically in the case where an aqueous solution of a strong acid is put above a denser aqueous solution of a color indicator in the gravity field. The neutralization reaction between the acid and the color indicator as well as their differential diffusion modifies the initially stable density profile in the system and can trigger convective motions both above and below the initial contact line. The type of patterns observed as well as their wavelength and the speed of the reaction front are shown to depend on the value of the initial concentrations of the acid and of the color indicator and on their ratio. A reaction-diffusion model based on charge balances and ion pair mobility explains how the instability scenarios change when the concentration of the reactants are varied.Fil: Kuster, S.. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; ArgentinaFil: Riolfo, L. A.. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; ArgentinaFil: Zalts, Anita. Universidad Nacional de General Sarmiento; ArgentinaFil: El Hasi, C.. Universidad Nacional de General Sarmiento; ArgentinaFil: Almarcha, C.. Université Libre de Bruxelles; BélgicaFil: Trevelyan, P.M.J.. Université Libre de Bruxelles; BélgicaFil: De Wit, A.. Université Libre de Bruxelles; BélgicaFil: D'onofrio, Alejandro Gustavo. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Management of multidrug resistant Gram-negative bacilli infections in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant (MDR) Gram-negative bacilli (GNB), as they are frequently exposed to antibiotics and the healthcare setting, and are regulary subject to invasive procedures. Nevertheless, no recommendations concerning prevention and treatment are available. A panel of experts revised the available evidence; this document summarizes their recommendations: (1) it is important to characterize the isolate´s phenotypic and genotypic resistance profile; (2) overall, donor colonization should not constitute a contraindication to transplantation, although active infected kidney and lung grafts should be avoided; (3) recipient colonization is associated with an increased risk of infection, but is not a contraindication to transplantation; (4) different surgical prophylaxis regimens are not recommended for patients colonized with carbapenem-resistant GNB; (5) timely detection of carriers, contact isolation precautions, hand hygiene compliance and antibiotic control policies are important preventive measures; (6) there is not sufficient data to recommend intestinal decolonization; (7) colonized lung transplant recipients could benefit from prophylactic inhaled antibiotics, specially for Pseudomonas aeruginosa; (8) colonized SOT recipients should receive an empirical treatment which includes active antibiotics, and directed therapy should be adjusted according to susceptibility study results and the severity of the infection.J.T.S. holds a research contract from the Fundación para la Formación e Investigación de los Profesionales de la Salud de Extremadura (FundeSalud), Instituto de Salud Carlos III. M.F.R. holds a clinical research contract “Juan Rodés” (JR14/00036) from the Spanish Ministry of Economy and Competitiveness, Instituto de Salud Carlos III