Dark matter within the minimal flavour violation ansatz

Minimal Flavour Violation hypothesis can provide an attractive framework for Dark Matter (DM). We consider scalar DM candidates carrying flavour quantum numbers and whose representation under the flavour group guarantees DM stability. They interact with the Standard Model fields through Higgs portal at renormalisable level and also to quarks through dimension-6 operators. We provide a systematic analysis of the viable parameter space for the DM fields, which are triplet of the flavour group, considering several DM-quark interactions. In this framework, we analyse in which cases the viable parameter space differs from Higgs portal models thanks to the underlying flavour structure. In contrast to minimal Higgs portal scenarios, we find that light DM in the GeV mass range as well as heavier candidates above Higgs resonance could be allowed by colliders, direct and indirect DM detection searches as well as flavour constraints. The large mass regime above the top mass could even be beyond the reach of future experiments such as Xenon 1T.Comment: 11 pages, 2 figures; v2: references added, version published on Phys.Lett.

El rol del tutor de ABP en el desarrollo del razonamiento hipotético deductivo en los estudiantes

Numerosos autores han orientado sus investigaciones a la descripción del razonamiento clínico, tales como Patel (2009) y Elstein (2002), específicamente en el área de la cognición Médica. Los resultados de estos trabajos intentan describir y clasificar al razonamiento clínico identificando diversos tipos. En especial se reconocen dos de ellos, el razonamiento hipotético deductivo y el de reconocimiento por patrones. Los expertos utilizan razonamiento por patrones o no analítico y usan el razonamiento hipotético deductivo cuando se les presenta un problema no común o que no es de su área. El presente estudio se orienta a analizar y comparar las intervenciones de los tutores en función del desarrollo del razonamiento hipotético deductivo en los primeros años de la carrera de medicina, en el contexto del aprendizaje basado en problemas. Se busca analizar las intervenciones de tutores antes de instancias de reflexión y posterior a las mismas. Material y métodos: Metodología cuantitativa con observación no participante y grabación de sesiones tutoriales. La muestra se seleccionó de manera intencional. Los sujetos que participaron en el estudio fueron 4 tutores de ciclo básico, correspondientes a dos cursos y 40 estudiantes. Al finalizar cada sesión tutorial los sujetos participantes y el investigador reflexionaron sobre la importancia de promover el razonamiento hipotético deductivo. Esto se acompañó de grillas de autoevaluación que contenían las siguientes categorías: habilidades respecto al manejo de la información, identificación y jerarquización del problema, elaboración, fundamentación y selección de hipótesis y formulación de conclusiones. Las sesiones fueron transcriptas y el análisis se realizó de acuerdo a las categorías preestablecidas anteriormente mencionadas. Resultados: Del total de intervenciones del tutor el 47,3% se orienta a aspectos relacionados con el razonamiento hipotético deductivo y el 52.7% se orienta a otros objetivos. Se presenta a continuación los porcentajes correspondientes a aspectos relacionados con el razonamiento hipotético deductivo.Fil: Merlo, María Laura . Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: López, María José. Universidad Nacional de Cuyo. Facultad de Ciencias Médica

Transition metal-based bimetallic catalysts for the chemoselective hydrogenation of furfuraldehyde

In this work, the liquid-phase chemoselective hydrogenation of furfural was studied, employing Pt, Rh and Ni-based catalysts. Bimetallic systems, containing different amounts of tin, were obtained by means of controlled surface reactions between a monometallic catalyst and Sn(C4H 9)4. The results obtained when monometallic catalysts were employed suggest a relationship between metal properties and the activity and selectivity obtained. All systems allowed obtaining furfuryl alcohol with high selectivity (99, 97 and 76% were achieved with Pt, Rh and Ni catalysts, respectively). The addition of tin has different effects on the three systems, both in terms of conversion and selectivity. An interesting result was obtained for the Ni-based catalysts, for which the addition of tin led to a significant increase in furfuryl alcohol selectivity and, depending on the Sn/Ni ratio, also to an increase in the catalytic activity of the system.Centro de Investigación y Desarrollo en Ciencias Aplicada

Transition metal-based bimetallic catalysts for the chemoselective hydrogenation of furfuraldehyde

In this work, the liquid-phase chemoselective hydrogenation of furfural was studied, employing Pt, Rh and Ni-based catalysts. Bimetallic systems, containing different amounts of tin, were obtained by means of controlled surface reactions between a monometallic catalyst and Sn(C4H 9)4. The results obtained when monometallic catalysts were employed suggest a relationship between metal properties and the activity and selectivity obtained. All systems allowed obtaining furfuryl alcohol with high selectivity (99, 97 and 76% were achieved with Pt, Rh and Ni catalysts, respectively). The addition of tin has different effects on the three systems, both in terms of conversion and selectivity. An interesting result was obtained for the Ni-based catalysts, for which the addition of tin led to a significant increase in furfuryl alcohol selectivity and, depending on the Sn/Ni ratio, also to an increase in the catalytic activity of the system.Neste trabalho foi estudada a hidrogenação quimiosseletiva em fase líquida do furfural, empregando-se catalisadores baseados em Pt, Rh e Ni. Sistemas bimetálicos, contendo diferentes quantidades de estanho, foram obtidos por meio de reações de superfície controlada entre um catalisador monometálico e Sn(C4 H9)4. Quando foram utilizados catalisadores monometálicos, os resultados obtidos sugerem uma relação entre as propriedades do metal e da atividade e seletividade. Todos os sistemas permitiram a obtenção do álcool furfurílico com alta seletividade (99, 97 e 76% com catalisadores de Pt, Rh e Ni, respectivamente). A adição de estanho tem efeitos diferentes sobre os três sistemas, tanto em termos de conversão quanto na seletividade. Um resultado interessante foi obtido para os catalisadores baseados em Ni, para os quais a adição de estanho levou a um aumento significativo da seletividade do álcool furfurílico e, dependendo da razão Sn/Ni, também há um aumento na atividade catalítica do sistemaFil: Vetere, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Merlo, Andrea Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Ruggera, José Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Casella, Mónica Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

Social context shapes cognitive abilities: associative memories are modulated by fight outcome and social isolation in the crab Neohelice granulata

Cognitive abilities of an animal can be influenced by distinct social experiences. However, the extent of this modulation has not been addressed in different learning scenarios: are all tasks similarly affected by social experiences? In the present study, we analyzed the effect of social dominance in aversive and appetitive memory processes in the crab Neohelice granulata. In addition, we studied the influence of social isolation on memory ability. Social dominance experiments consisted of an agonistic phase immediately followed by a memory phase. During the agonistic phase, matched pairs of male crabs were staged in 10-min encounters and the dominant or subordinate condition of each member of the dyad was determined. During the memory phase, crabs were trained to acquire aversive or appetitive memory and tested 24 h later. Results showed that the agonistic encounter can modulate long-term memory according to the dominance condition in such a way that memory retention of subordinates results higher than their respective dominant. Remarkably, this result was found for both aversive and appetitive memory tasks. In addition, we found that isolated animals showed no memory retention when compared with animals that remained grouped. Altogether this work emphasizes the importance of social context as a modulator of cognitive abilities.Fil: Santos, María Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Merlo, Santiago Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Kaczer, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Pedreira, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Characteristics and Treatment Outcome of Cerebrospinal Fluid Shunt-Associated Infections in Adults: A Retrospective Analysis over an 11-Year Period

Background. Data on infections associated with cerebrospinal fluid (CSF) shunts among adults are limited. Therefore, we performed a retrospective study of shunt-associated infections in adults. Methods. Patients aged ⩾12 years with infections associated with CSF shunts and admitted to our institution (University Hospital Basel, Basel, Switzerland) from January 1996 through December 2006 were included retrospectively. Hospital charts were reviewed, and follow-up was performed by assessment of later hospitalizations and telephone contact with patients, their families, and general practitioners. Results. Seventy-eight episodes of infection associated with ventriculoperitoneal shunt (65 episodes), ventriculoatrial shunt (7), lumboperitoneal shunt (5), and central nervous system reservoir (1) were included. Median patient age was 50 years (range, 12-80 years); 49 (63%) of the patients were men. Most infections (48 [62%]) manifested within 1 month after shunt surgery. Fever was present in 61 episodes (78%), neck stiffness was present in 35 (45%), and local signs of infection were present in 38 (49%). In CSF, leukocyte count was >5×106 cells/L in 80% of episodes, and lactate level was >1.9 mmol/L in 81% of episodes. Leukocyte counts were significantly higher in CSF obtained by use of lumbar puncture (median leukocyte count, 573×106 cells/L; P=.001) and valve puncture (median leukocyte count, 484×106 cells/L; P=.016) than in ventricular CSF (median leukocyte count, 8.5×106 cells/L). Overall, results of CSF cultures were positive in 66% of episodes (48 of 73 episodes for which CSF was collected), and microorganisms were isolated more often from valve puncture CSF specimens (91% of specimens) and ventricular CSF specimens (70%) than from lumbar CSF specimens (45%). The most prevalent organisms were coagulase-negative staphylococci (found in 37% of specimens), Staphylococcus aureus (18%), and Propionibacterium acnes (9%). A surgical procedure was performed to treat infection in 63 (81% of the episodes) (shunt removal in 37 episodes and shunt replacement in 26). The shunt was retained without surgery for 15 episodes (19% of episodes). Median duration of patient follow-up was 4.6 years (range, 0.1-11.1 years), with favorable treatment outcome in 75 (96%) of 78 cases. One of the 63 patients who underwent surgical treatment of shunt-associated infection experienced infection relapse; of the 15 patients who received treatment with antibiotics alone, 1 experienced infection relapse and 1 died. The 2 relapses involved rifampin-resistant coagulase-negative staphylococci. Conclusions. Shunt-associated infections among adults often present with nonspecific clinical signs, and affected patients can have normal CSF leukocyte counts and lactate levels; therefore, a high index of suspicion and improved methods are required for diagnosing shunt-associated infectio

Experimental and theoretical investigation of the enantioselective hydrogenation of ethyl pyruvate with a Pt catalyst with new non-cinchona chiral modifiers

The enantioselective hydrogenation of ethyl pyruvate using a Pt/SiO2 catalyst modified with six different chiral modifiers was studied. The chiral modifiers chosen were: (S)-(+)-1-aminoindan, (R)-(−)-1-aminoindan, (1R,2S)-(+)-cis-1- amino-2-indanol, (1S,2R)-(−)-cis-1-amino-2-indanol, (S)-(+)-1-indanol and (R)-(−)-1-indanol.An excess of the (R) enantiomer of the product of 63% and 45% with (S)-(+)-1-aminoindan and (R)-(−)-1-aminoindan modifiers, respectively was obtained. When using (1S,2R)-(−)-cis-1-amino-2-indanol and (1R,2S)-(+)-cis-1-amino-2-indanol, the enantiomeric excess (ee%) obtained was 30% and 5%, respectively, while with both indanols ee% did not exceed 8%. Molecular modeling of the complex formed between the chiral modifier and ethyl pyruvate performed by DFT calculations allowed predicting the values of ee% obtained experimentally. The low ee% value obtained both aminoindanol chiral modifiers were used, could be explained by the analysis of non-covalent interactions (NCI) method. These calculations demonstrated the presence of an intramolecular hydrogen bond in the structure of these modifiers.Centro de Investigación y Desarrollo en Ciencias Aplicada

Sustentabilidade/resiliência dos componentes da matéria orgânica do solo numa região árida da Argentina

This short communication presents a novel approach to determining the soil sustainability of productive practices in an Argentinean arid region, using the resilience degree of soil organic matter components. The study was conducted in four sites of the Arid Chaco region of the Cordoba province: one undisturbed site, two sites with livestock (with total and with selective clearing) and one site with agriculture. In each site three soil samples were taken and total soil organic matter, fulvic and humic acids, and non-humic substances were analyzed. Variations of each component (%) between each productive practice and the undisturbed site were calculated in order to establish the resilience degree. The livestock soils showed: a) moderate resilience for non-humic substances, b) low resilience for organic matter and humic acids, and c) no resilience for fulvic acids. The agricultural soils showed: a) low resilience for total organic matter and non-humic substances, and b) no resilience for fulvic and humic acids. We conclude that this approach is a powerful tool for establishing management practices according to each particular situation, allowing improved productivity in arid regions.Se analizó el grado de resiliencia de los componentes de la materia orgánica del suelo para establecer la sustentabilidad de las prácticas productivas en una región árida de Argentina. Se trabajó en cuatro sitios en el Chaco Árido de la provincia de Córdoba: un sitio testigo, 2 sitios con ganadería (con desmonte total y selectivo) y un sitio con agricultura. En cada sitio se tomaron tres muestras de suelo y se analizó en contenido de materia orgánica total, ácido fúlvicos, ácidos húmicos y sustancias no humificadas. Se calculó la variación (%) de cada componente entre los sitios productivos y el sitio testigo, para establecer el grado de resiliencia. En los sitios con ganadería las sustancias no humificadas fueron moderadamente resilientes, la materia orgánica total y los ácidos húmicos escasamente resilientes y los ácidos fúlvicos no resilientes. En el sitio con agricultura la materia orgánica total y las sustancias no humificadas fueron escasamente resilientes, mientras que los ácidos fúlvicos y húmicos fueron no resilientes. Se concluye que este método de evaluación de la sustentabilidad es una excelente herramienta para establecer las prácticas de manejo de acuerdo a cada situación en particular, permitiendo mejorar la productividad de las regiones áridas.O grau de resiliência dos componentes da matéria orgânica do solo foi analisado para estabelecer a sustentabilidade das práticas de produção numa região árida da Argentina. Recorreu-se a quatro locais na região árida do Chaco província de Córdoba: um local controlo, 2 locais com produção pecuária e um local com produção agrícola. Colheram-se três amostras de solo em cada um dos locais testados e procedeu-se à determinação dos teores de matéria orgânica total, substâncias não humificadas, e ácidas fúlvicos e húmicos. Calculou-se a variação (%) de cada componente entre locais com produção e o controlo para estabelecer o grau deresiliência. Os locais com produção pecuária apresentaram substâncias não humificadas com resiliência moderada, matéria orgânica e ácidos húmicos com baixa resiliência e ácidos fúlvicos não resilientes. No local com produção agrícola a matéria orgânica total e as substâncias não humificadas apresentaram baixa resiliência, enquanto os ácidos húmicos e fúlvicos não apresentaram resiliência. Dos resultados obtidos conclui-se que este método de avaliação da sustentabilidade é uma excelente ferramenta para estabelecer práticas de gestão de acordo com cada situação em particular, permitindo melhorar a produtividade das regiões áridas.Fil: Vazquez, Carolina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Recursos Naturales. Cátedra de Microbiología Agrícola; ArgentinaFil: Merlo, Carolina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Recursos Naturales. Cátedra de Microbiología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Noe, Laura Belen. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Recursos Naturales. Cátedra de Microbiología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romero, Carlos. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Recursos Naturales. Cátedra de Microbiología Agrícola; ArgentinaFil: Abril, Adriana. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Recursos Naturales. Cátedra de Microbiología Agrícola; ArgentinaFil: Carranza, Carlos Andrés. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Córdoba. Estación Experimental Agropecuaria Manfredi. Estación Forestal Villa Dolores; Argentin

Renal function and physical fitness after 12-mo supervised training in kidney transplant recipients

To evaluate the effect of a 12-mo supervised aerobic and resistance training, on renal function and exercise capacity compared to usual care recommendations