Theoretical study of electronic transport through a small quantum dot with a magnetic impurity

We model a small quantum dot with a magnetic impurity by the Anderson Hamiltonian with a supplementary exchange interaction term. The transport calculations are performed by means of the Green functions within the equation of motion scheme, in which two decoupling procedures are proposed, for high and low temperatures, respectively. The paper focuses on the charge fluctuations for such a system, aspect not addressed before, as well as on the Kondo resonance. We show a specific role of the excited state, which can be observed in transport and in spin-spin correlations. Our studies show on a new many-body feature of the phase shift of transmitted electrons, which is manifested in a specific dip. In the Kondo regime, our calculations complement existing theoretical results. The system shows three Kondo peaks in the density of states: one at the Fermi energy and two side peaks, at a distance corresponding to the singlet-triplet level spacing. The existence of the central peak is conditioned by a degenerate state (the triplet) below the Fermi energy.Comment: 12 pages, 4 figure

Coulomb oscillations of the Fano-Kondo effect and zero bias anomalies in the double dot meso-transistor

We investigate theoretically the transport properties of the side-coupled double quantum dots in connection with the experimental study of Sasaki {\it et al.} Phys.Rev.Lett.{\bf 103}, 266806 (2009). The novelty of the set-up consists in connecting the Kondo dot directly to the leads, while the side dot provides an interference path which affects the Kondo correlations. We analyze the oscillations of the source-drain current due to the periodical Coulomb blockade of the many-level side-dot at the variation of the gate potential applied on it. The Fano profile of these oscillations may be controlled by the temperature, gate potential and interdot coupling. The non-equilibrium conductance of the double dot system exhibits zero bias anomaly which, besides the usual enhancement, may show also a suppression (a dip-like aspect) which occurs around the Fano {\it zero}. In the same region, the weak temperature dependence of the conductance indicates the suppression of the Kondo effect. Scaling properties of the non-equilibrium conductance in the Fano-Kondo regime are discussed. Since the SIAM Kondo temperature is no longer the proper scaling parameter, we look for an alternative specific to the double-dot. The extended Anderson model, Keldysh formalism and equation of motion technique are used.Comment: 19 pages, 8 figure

Educating on professional habits: attitudes of medical students towards diverse strategies for promoting influenza vaccination and factors associated with the intention to get vaccinated

BACKGROUND: Influenza vaccination coverage in medical students is usually low. Unlike health care workers, there is little information on the attitudes to and predictors of vaccination among medical students, and their attitudes towards institutional strategies for improving rates are unknown. METHODS: This cross-sectional study evaluated the effect of three influenza vaccination promotional strategies (Web page, video and tri-fold brochure) on medical students’ intention to get vaccinated and associated factors. A total of 538 medical students were asked to answer an anonymous questionnaire assessing the intention to get vaccinated after exposure to any of the promotional strategies. Sociodemographic data collected included: sex, age, university year, influenza risk group and cohabiting with member of a risk group. RESULTS: Four hundred twenty-one students answered the questionnaire, of whom 312 (74.1%) were female, 113 (26.8%) had done clinical rotations, and 111 (26.6%) reported intention to get the flu shot. Logistic regression showed the web group had a greater intention to get vaccinated than the reference group (OR: 2.42 95% CI: 1.16-5.03). Having done clinical rotations (OR: 2.55 95% CI: 1.36-4.38) and having received the shot in previous flu seasons (OR: 13.69 95% CI: 7.86-23.96) were independently associated with the intention to get vaccinated. CONCLUSION: Given that previous vaccination is a factor associated with the intention to get vaccinated, education on vaccination of health care workers should begin while they are students, thereby potentiating the habit. In addition, the intention to get vaccinated was greater during the clinical phase of the university career, suggesting this is a good time to introduce promotion strategies. Online promotional campaigns, such as a thematic Web to promote vaccination of health workers, could improve the intention to get vaccinated

Factors associated with risk behavior in travelers to tropical and subtropical regions

BACKGROUND: Recent decades have seen a rise in population movements and, therefore, the spread of tropical diseases and changes in the epidemiology of global disease patterns. Only 50% of travelers to tropical areas receive pre-travel advice and most of them present risk behaviors for acquiring infections. The aim of this study was to describe the clinical and epidemiological characteristics of travelers and identify factors associated with risk behaviors. METHODS: We made a retrospective, descriptive and analytical study of 772 travelers consulting a tropical medicine clinic in Barcelona in 2010. Data on demographic and clinical variables, travel characteristics and risk behaviors were collected. RESULTS: Among all travelers studied, 65.8% (466/708) received pre-travel advice and 30.7% (209/680) took malaria prophylaxis. At least one risk behavior was reported by 82.6% (587/711) of travelers. People travelling for 1-6 months had a 3-fold higher likelihood of experiencing risk behaviors than people travelling for <1 month (95% CI 1.54-5.81, p=0.001), and those travelling for >6 months had a 13-fold higher likelihood (95% CI 3.11-56.14, p<0.001) compared with the same group. Increasing age was associated with presenting less risk behaviors. CONCLUSIONS: Younger travelers and those making longer trips have a higher number of risk behaviors. Strategies emphasizing advice on risk behavior should focus on these groups

Immunogenicity and immunization costs of adjuvanted versus non-adjuvanted hepatitis B vaccine in chronic kidney disease patients

Hepatitis B virus (HBV) vaccination is recommended for all susceptible chronic pre-hemodialysis and hemodialysis patients. This study assessed the immunogenicity of HBV vaccines (adjuvanted and non-adjuvanted) in chronic kidney disease patients vaccinated at the Hospital Clinic of Barcelona (Spain) between January 2007 and July 2012. In addition, the costs for the health system were evaluated according to the proportion of vaccine responders after receiving either vaccine. Patients receiving three doses of hepatitis B adjuvanted vaccine were three times more likely to seroconvert than patients immunized with non-adjuvanted vaccines, OR 3.56 (95% CI 1.84-6.85). This resulted in fewer patients requiring a second course of HBV vaccination and fewer outpatient visits, saving more than euro9,500 per 100 patients. The higher immunogenicity of the adjuvanted HBV vaccine would counterbalance the lower costs associated with the non-adjuvanted vaccine

Towards a runtime verification framework for the Ada Programming Language

Runtime verification is an emerging discipline that investigates methods and tools to enable the verification of program properties during the execution of the application. The goal is to complement static analysis approaches, in particular when static verification leads to the explosion of states. Non-functional properties, such as the ones present in real-time systems are an ideal target for this kind of verification methodology, as are usually out of the range of the power and expressiveness of classic static analyses. In this paper, we present a framework that allows real-time programs written in Ada to be augmented with runtime verification capabilities. Our framework provides the infrastructures which is needed to instrument the code with runtime monitors. These monitors are responsible for observing the system and reaching verdicts about whether its behavior is compliant with its non-functional properties. We also sketch a contract language to extend the one currently provided by Ada, with the long term goal of having an elegant way in which runtime monitors can be automatically synthesized and instrumented into the target systems. The usefulness of the proposed approach is demonstrated by showing its use for an application scenario.This work was partially supported by Portuguese National Funds through FCT (Portuguese Founda- tion for Science and Technology) and by ERDF (European Regional Develop- ment Fund) through COMPETE (Operational Programme ’Thematic Factors of Competitiveness’), within projects FCOMP-01-0124-FEDER-037281 (CISTER), FCOMP-01-0124-FEDER-015006 (VIPCORE) and FCOMP-01-0124-FEDER- 020486 (AVIACC); and by FCT and EU ARTEMIS JU, within project ARTEMIS/0003/2012, JU grant nr. 333053 (CONCERTO)

Tendencias en la apicultura y pérdida de colonias de abejas melíferas en América Latina

Over the past decade, several countries have carried out monitoring programs of managed honey bee colonies, which suggest beekeeping difficulties, with high colony loss rates all over the world. Although Latin America plays a major role in the global honey supply, information about trends in beekeeping activities and honey bee colony losses are lacking. Using the Food and Agriculture Organization of the United Nations (FAO) dataset and a synthesis of unpublished data of colony losses survey carried out over the last 7 years, we reveal a worrying situation of the beekeeping in this region. The Latin American trends in honey production and beehive numbers are drifting from the global pattern, and several high colony loss rates were registered in this region. These results reveal the presence of beekeeping difficulties in Latin America. However, the variability in methods of colony loss survey across initiatives prevent proper conclusion on loss rates. Efforts are needed to adapt, centralize and standardize methods to monitor honey bee health and colony losses across countries in Latin America, the main objective of the “colony losses” working group at the LatinAmerican Society for Bee Research, SOLATINA, a large-scale platform created in 2017 to coordinate bee research programs in Latin America.Durante la última década, varios países han llevado a cabo programas de monitoreo de colmenas de abejas melíferas, que sugieren dificultades en la apicultura relacionadas con altas tasas de pérdida de colonias al rededor del mundo. Aunque América Latina juega un papel importante en la producción mundial de miel, hay un vacío de información sobre la actividad apícola y las pérdidas de colonias en la región. Utilizando el conjunto de datos de la FAO y una síntesis de datos inéditos de encuestas sobre pérdidas de colonias realizada en los últimos siete años, revelamos una preocupante situación para la apicultura en esta región. Las tendencias latinoamericanas en la producción de miel y el número de colonias se desvían del patrón global, y se registran altas tasas de pérdidas de colonias en la región. Estos resultados revelan dificultades en el desarrollo apícola latinoamericano. Sin embargo, la variabilidad en los métodos de valoración de la pérdida de colonias en las diferentes iniciativas impide llegar a conclusiones definitivas sobre las tasas de pérdidas. Se necesitan esfuerzos para adaptar, centralizar y estandarizar los métodos de monitoreo de la salud de las abejas melíferas y las pérdidas de colonias en todos los países de América Latina. Esto constituye el principal objetivo del grupo de trabajo “Pérdida de colonias” de la Sociedad Latinoamericana de Investigación en Abejas, SOLATINA, una plataforma a gran escala creada en 2017 para coordinar los programas de investigación apícola en América Latina.Facultad de Ciencias Veterinaria

Trends in beekeeping and honey bee colony losses in Latin America

Fil: Requier, Fabrice. Universidad Nacional de Río Negro. Sede Andina; Argentina.Fil: Antúnez, Karina. Instituto de Investigaciones Biológicas Clemente Estable; Uruguay.Fil: Morales, Carolina L. Universidad Nacional del Comahue; Argentina.Fil: Aldea Sánchez, Patricia. Facultad de Ciencias de la Universidad Mayor; Chile.Fil: Castilhos, Dayson. Universidade Federal Rural do Semi-Arido, Brasil.Fil: Garrido, Paula M. Universidad Nacional de Mar del Plata; Argentina.Fil: Giacobino, Agostina. Consejo Nacional de Investigaciones Científicas y Técnicas e Instituto Nacional de Tecnología Agropecuaria; Argentina.Fil: Reynaldi, Francisco J. Universidad Nacional de La Plata y Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Rosso Londoño, Juan M. Reserva Natural Hacienda Agroecológica El Paraíso y Universidad Distrital Francisco José de Caldas; Colombia.Fil: Santos, Estela. Comisión Honoraria de Desarrollo Apícola; Uruguay.Fil: Garibaldi, Lucas Alejandro. Universidad Nacional de Río Negro. Sede Andina; Argentina.Over the past decade, several countries have carried out monitoring programs of managed honey bee colonies, which suggest beekeeping difficulties, with high colony loss rates all over the world. Although Latin America plays a major role in the global honey supply, information about trends in beekeeping activities and honey bee colony losses are lacking. Using the Food and Agriculture Organization of the United Nations (FAO) dataset and a synthesis of unpublished data of colony losses survey carried out over the last 7 years, we reveal a worrying situation of the beekeeping in this region. The Latin American trends in honey production and beehive numbers are drifting from the global pattern, and several high colony loss rates were registered in this region. These results reveal the presence of beekeeping difficulties in Latin America. However, the variability in methods of colony loss survey across initiatives prevent proper conclusion on loss rates. Efforts are needed to adapt, centralize and standardize methods to monitor honey bee health and colony losses across countries in Latin America, the main objective of the “colony losses” working group at the Latin-American Society for Bee Research, SOLATINA, a large-scale platform created in 2017 to coordinate bee research programs in Latin America