Dimensionality of the spatio-temporal entanglement of PDC photon pairs

In this work the Schmidt number of the two-photon state generated by parametric-down conversion (PDC) is evaluated in the framework of a fully spatio-temporal model for PDC. A comparison with the results obtained in either purely spatial or purely temporal models shows that the degree of entanglement of the PDC state cannot be trivially reduced to the product of the Schmidt numbers obtained in models with lower dimensionality, unless the detected bandwidth is very narrow. This result is a consequence of the non-factorability of the state in the spatial and temporal degrees of freedoms of twin photons. In the limit of a broad pump beam, we provide a geometrical interpretation of the Schmidt number, as the ratio between the volume of the phase matching region and of a correlation volume.Comment: 17 pages, 10 figures. Submitted to Phys. Rev.

Pressure-induced transformations in LiCl–H2O at 77 K

A systematic study of the properties of high-density amorphous ice (HDA) in the presence of increasing amounts of salt is missing, especially because it is challenging to avoid ice crystallization upon cooling the pressurized liquid. In order to be able to study HDA also in the presence of small amounts of salt, we have investigated the transformation behaviour of quenched aqueous LiCl solutions (mole fraction x 1 GPa. The observed densification is consistent with the idea that a freeze concentrated LiCl solution of x = 0.14 (R = 6) segregates, which transforms to the glassy state upon cooling, and that the densification is only due to the Ih → HDA transition. Also the XRD patterns and DSC scans are almost unaffected by the presence of the segregated glassy LiCl solution. Upon heating at ambient pressure HDA experiences the polyamorphic transition to low-density amorphous ice (LDA) at ∼120 K, even at x ∼ 0.10. Based on the latent heat evolved in the transition we suggest that almost all water in the sample transforms to an LDA-like state, even the water in the vicinity of the ions. The glassy LiCl solution acts as a spectator that does not shift the transformation temperature significantly and experiences a glass-to-liquid transition at ∼140 K prior to the crystallization to cubic ice. By contrast, at x > 0.12 the phenomenology completely changes and is now dominated by the salt. Hexagonal ice no longer forms upon quenching the LiCl solution, but instead LDA forms. A broad pressure-induced transformation at >0.6 GPa can be attributed to the densification of LDA, the glassy LiCl solution and/or glassy hydrates.Fil: Ruiz, G. N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Innsbruck; AustriaFil: Bove, L. E.. Universite Pierre et Marie Curie; Francia. Ecole Polytechnique Federale de Lausanne; SuizaFil: Corti, Horacio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Loerting, T.. Universidad de Innsbruck; Austri

Near-infrared spectroscopy study of tourniquet-induced forearm ischaemia in patients with coronary artery disease

Near-Infrared Spectroscopy (NIR) can be employed to monitor local changes in haemodynamics and oxygenation of human tissues. A preliminary study has been performed in order to evaluate the NIRS transmittance response to induced forearm ischaemia in patients with coronary artery disease (CAD). The population consists in 40 patients with cardiovascular risk factors and angiographically documented CAD, compared to a group of 13 normal subjects. By inflating and subsequently deflating a cuff placed around the patient arm, an ischaemia has been induced and released, and the patients have been observed until recovery of the basal conditions. A custom LAIRS spectrometer (IRIS) has been used to collect the backscattered light intensities from the patient forearm throughout the ischaemic and the recovery phase. The time dependence of the near-infrared transmittance on the control group is consistent with the available literature. On the contrary, the magnitude and dynamics of the NIRS signal on the CAD patients show deviations from the documented normal behavior, which can be tentatively attributed to abnormal vessel stiffness. These preliminary results, while validating the performance of the IRIS spectrometer, are strongly conducive towards the applicability of the NIRS technique to ischaemia analysis and to endothelial dysfunction characterization in CAD patients with cardiovascular risk factors.Publisher PD

Calorimetric study of water's two glass transitions in the presence of LiCl

A DSC study of dilute glassy LiCl aqueous solutions in the water-dominated regime provides direct evidence of a glass-to-liquid transition in expanded high density amorphous (eHDA)-type solutions. Similarly, low density amorphous ice (LDA) exhibits a glass transition prior to crystallization to ice Ic. Both glass transition temperatures are independent of the salt concentration, whereas the magnitude of the heat capacity increase differs. By contrast to pure water, the glass transition endpoint for LDA can be accessed in LiCl aqueous solutions above 0.01 mole fraction. Furthermore, we also reveal the endpoint for HDA's glass transition, solving the question on the width of both glass transitions. This suggests that both equilibrated HDL and LDL can be accessed in dilute LiCl solutions, supporting the liquid-liquid transition scenario to understand water's anomalies.Fil: Ruiz, Guadalupe N.. Universidad de Innsbruck; Austria. Universidad Politécnica de Catalunya; EspañaFil: Amann Winkel, Katrin. AlbaNova University Center; Suecia. Universidad de Innsbruck; AustriaFil: Bove, Livia E.. Université Pierre et Marie Curie; FranciaFil: Corti, Horacio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina. Universidad de Buenos Aires; ArgentinaFil: Loerting, Thomas. Universidad de Innsbruck; Austri

Rapid progression of atherosclerotic coronary artery disease in patients with human immunodeficiency virus infection

We describe the case of a 39-year-old human immunodeficiency virus (HIV)-infected man with angiographically documented rapid progression of coronary artery disease. Over a time course of only 2 months, he developed high-grade stenosis of the left anterior descending coronary artery. The risk of myocardial infarction is increased in patients with HIV infection receiving antiretroviral therapy. However, the absolute risk is small and the marked overall benefits of antiretroviral therapy are evident. Patients receiving HIV protease inhibitors should be screened for hyperlipidemia, hyperglycemia, and hypertension. They may be candidates for lipid-lowering therapies depending on their long-term prognosis and individual risk of cardiovascular disease. Care is need because of possible drug interactions between lipid-lowering drugs and antiretroviral therapy. Invasive treatment of acute myocardial infarction does not differ from that in patients not infected with HIV. The rate of progression of coronary artery disease and the restenosis rate, however, are often unexpectedly high in these patient

Transfer of Benzophenones from Soil to Plants

Benzophenones (BPs) include different compounds whose molecular structure is based on diphenyl ketone (benzophenone, BP). Some benzophenones have been reported to have estrogenic activity and some compounds have been classified as possibly carcinogenic to humans. Specific studies should be carried out about possible pollution of soils due to the use of biosolids and/or treated wastewater in agriculture practices, in particular to understand the transport of BPs to the edible parts of plants and risk for humans due to their consumption. In this work, the transfer of BP and BP-3 to edible vegetables cultivated on polluted soil was investigated. Lettuce and tomatoes were selected due to their high worldwide per capita consumption rates. Plants were cultivated in pots filled with agricultural soil artificially contaminated with BP or BP-3 and in pots with uncontaminated soil (blank pots). At the beginning of tests (time T0) three soil samples from each pot were collected and analyzed. Lettuce was cultivated for about 55 d; at the end of this period (time T1), the edible part of each plant was collected and analyzed. Tomatoes were collected at different times (T1 = 54 d, T2 = 70 d, T3 = 83 d and T4 = 92 d) due to the different ripening time of the fruits; in the BP-3 pot, tomatoes could be collected only at time T3 and T4, because no ripe fruits were available before. Soil samples were also collected at the different times, by coring the soil next to the lettuce plant roots or the plants from which tomatoes had been grabbed. Commercial pre-washed lettuce, raw lettuce and tomatoes from conventional farming and organic farming were also bought at a local store and analyzed. BP concentrations in the contaminated soils remained constant over time except for the tomato pot from time T3, while BP-3 concentrations decreased over time. As for the vegetables, BP (at T2) and BP-3 (at T3 and T4) in tomatoes were higher than in the Blank. BP and BP-3 concentrations found in the vegetables cultivated in this study were similar to those measured in the commercial vegetables, except for BP-3 in tomatoes at T3

Evaluación de competencias transversales mediante el uso de portafolio digital: el caso de la asignatura de teoría y práctica de la investigación educativa

Podeu consultar el document complet a: http://diposit.ub.edu/dspace/handle/2445/65797Esta experiencia de trabajo se enmarca dentro del Proyecto de Innovación Docente (PID_2012 IP: Rubio,M.J.) Un sistema de portafolio digital para la mejora de competencias transversales de la Universidad de Barcelona. La implementación de esta experiencia tiene por objetivo poder integrar a lo largo de la carrera de Pedagogía el uso del portafolio digital como una herramienta básica, plural y global en la adquisición y evaluación de las competencias transversales. El presente trabajo trata de presentar la experiencia de la asignatura de Teoría y Práctica de la Investigación Educativa. El portafolio digital pretende favorecer la mejora del aprendizaje de los estudiantes basándose en competencias y estableciendo una metodología de evaluación continuada, tal como sugiere el Espacio Europeo de Educación Superior. Las competencias transversales que se pretenden desarrollar con la experiencia son: a) capacidad de toma de decisiones; y b) capacidad comunicativa escrita relacionada con la investigación. La metodología de trabajo consiste en integrar estrategias que favorezcan el desarrollo de las competencias propuestas y que permitan al estudiante auto-gestionar su proceso de aprendizaje, utilizando el portafolio como ayuda fundamental para esto. Se presentan algunos resultados de la experiencia respecto a la auto percepción de los estudiantes sobre las competencias trabajadas

Learning to manage and share data: jump-starting the research methods curriculum

Researchers? responsibilities towards their research data are changing across all domains of social scientific endeavour. Government, funders and publishers expect greater transparency of, open access to, and re-use of research data, and fears over data loss call for more robust information security practices. Researchers must develop, enhance and professionalise their research data management skills to meet these challenges and to deal with a rapidly changing data sharing environment. This paper sets out how we have contributed to jump-starting the research methods training curriculum in this field by translating high-level needs into practical guidance and training activities. Our pedagogical approach involves applicable, easy-to-digest, modules based on best practice guidance for managing and sharing research data. In line with recent findings on successful practices in methods teaching, we work on the principle of embedding grounded learning activities within existing narratives of research design and implementation