3,179 research outputs found

    The Predictive Information Content of External Imbalances for Exchange Rate Returns: How Much Is It Worth?

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    This paper examines the exchange rate predictability stemming from the equilibrium model of international financial adjustment developed by Gourinchas and Rey (2007). Using predictive variables that measure cyclical external imbalances for country pairs, we assess the ability of this model to forecast out-of-sample four major US dollar exchange rates using various economic criteria of model evaluation. The analysis shows that the model provides economic value to a risk-averse investor, delivering substantial utility gains when switching from a portfolio strategy based on the random walk benchmark to one that conditions on cyclical external imbalances.foreign exchange; predictability; global imbalances; fundamentals.

    La ventana indiscreta. La Historia y la Antropología Jurídicas a través de la emoción de sus textos

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    El monográfico que editamos en este quinto número de prohistoria es el resultado de una convocatoria realizada desde la revista, durante el año 2000, con la intención de confeccionar un dossier. La anchura de la respuesta está a la vista: las autoras y los autores que publican aquí sus investigaciones, comparten la voluntad de intentar dirigir la mirada a través de esta ventana indiscreta, que muestra la tela por el revés, por el bies y por sus hilos, y discute certidumbres secularmente instaladas. Ignasi Terradas, entrevistado por Dalla Corte, reflexiona, toma posición y asigna potencia al campo que se despliega, en clave de investigación y acción, detrás de la etiqueta aparentemente académica de la antropología jurídica. Un grupo de notables antropólogos e historiadores observan y analizan distintas facetas del universo de los derechos, las jurisdicciones, los cambiantes perfiles de delitos y delincuentes, o discutiendo las vías de realización de la 'ciudadanía', una cantera de fuentes que, para las historiografias hispánica y rioplatense, comienza a arrojar ya resultados sustantivos sobre los cuales edificar nuevas versiones de sociedades que transitan, sobre todo, la disolución del Antiguo Régimen

    On-Chip Integrated Antenna Structures for Biomedical Implantable Sensors

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    AbstractThis paper explores some different geometries of integrated antennas in a 0.35 μm CMOS technology for devices operating in theinternationally available unlicensed 2.4 GHz band. At this frequency, the wavelength is short enough to implement smallantennas with dimensions economically feasible for silicon integration.Two are the considered different families of structures: spiral and dipole antennas, and some different antenna structures (singleloop,4-loop, double-4-loop, dipole, bent-dipole, meander-dipole) are examined, all modeled and simulated in Ansoft HFSS.Their inductive and radiation characteristics are compared. Chip dimensions of the order of one square millimetre are considered

    Experimental characterization and numerical analysis of the 4H-SiC p-i-n diodes static and transient behaviour

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    Steady-state and turn-off switching characteristics of aluminium-implanted 4H-SiC p-i-n diodes designed for high current density operation, are investigated experimentally and by mean of numerical simulations in the 298-523 K temperature range. The diodes present circular structure with a diameter of 350 &#956;m and employ an anode region with an aluminium depth profile peaking at 6?1019 cm&#8722;3 at the surface. The profile edge and the junction depth are located at 0.2 and 1.35 &#956;m, respectively. At room temperature the measured forward current density is close to 370 A/cm2 at 5 V with an ideality factor always less than 2 before high current injection or device series resistance became dominant. The transient analysis reveals a strong potential of this diodes for use in high speed, high power applications, especially at high temperature, with a very low turn-off recovery time (<80 ns) in the whole range of test conditions. The simulated results match the experimental data, showing that the switching performance is mainly due to the poor minority charge carrier lifetime estimated to be 15 ns for these implanted devices

    All-optical modulation in a CMOS-compatible amorphous silicon-based device

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    Active silicon photonic devices, which dynamically control the flow of light, have received significant attention for their use in on-chip optical networks. High-speed active silicon photonic modulators and switches rely on the plasma dispersion effect, where a change in carrier concentration causes a variation in the refractive index. The necessary electron and hole concentration change can be introduced either by optical pumping, or by direct electrical injection and depletion. We demonstrate a fast photoinduced absorption effect in low loss hydrogenated amorphous silicon (a-Si:H) waveguides deposited at a temperature as low as 190°C. Significant modulation (M% ~90%) occurs with a 1 mm-long device. We attribute the enhanced modulation to the significantly larger free-carrier absorption effect of a-Si:H. The complementary metal-oxide semiconductor (CMOS) compatible technology of a-Si:H could be considered as a promising candidate to enable an easy back-end integration with standard microelectronics processes

    Paediatric non-alcoholic fatty liver disease: impact on patients and mothers' quality of life

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    Background: Non-alcoholic fatty liver disease (NAFLD) is one of the causes of fatty liver in adults and is currently the primary form of chronic liver disease in children and adolescents. However, the psychological outcome (i.e. the behavioural problems that can in turn be related to psychiatric conditions, like anxiety and mood disorders, or lower quality of life) in children and adolescents suffering of NAFLD has not been extensively explored in the literature. Objectives: The present study aims at evaluating the emotional and behavioural profile in children suffering from NAFLD and the quality of life in their mothers. Patients and Methods: A total of 57 children (18 females/39 males) with NAFLD were compared to 39 age-matched control children (25 females/14 males). All participants were submitted to the following psychological tools to assess behavior, mood, and anxiety: the Multidimensional Anxiety Scale for Children (MASC), the Child Behavior Checklist (CBCL), and the Children's Depression Inventory (CDI). Moreover, the mothers of 40 NAFLD and 39 control children completed the World Health Organization Quality of Life-BREF (WHOQOL-BREF) questionnaire. Results: NAFLD children scored significantly higher as compared to control children in MASC (P = 0.001) and CDI total (P &lt; 0.001) scales. The CBCL also revealed significantly higher scores for NAFLD children in total problems (P = 0.046), internalizing symptoms (P = 0.000) and somatic complaints (P &lt; 0.001). The WHOQOL-BREF revealed significantly lower scores for the mothers of NAFLD children in the overall perception of the quality of life (P &lt; 0.001), and in the "relationships" domain (P = 0.023). Conclusions: Increased emotional and behavioural problems were detected in children with NAFLD as compared to healthy control children, together with an overall decrease in their mothers' quality of life. These results support the idea that these patients may benefit from a psychological intervention, ideally involving both children and parents, whose quality of life is likely negatively affected by this disease

    Some Considerations on the Behaviour of Bolted Stainless-Steel Beam-to-Column Connections: A Simplified Analytical Approach

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    Stainless-steel has proven to be a first-class material with unique mechanical properties for a variety of applications in the building and construction industry. High ductility, strain hardening, durability and aesthetic appeal are only a few of them. From a specific point of view, its nonlinear stress–strain behaviour appears capable of providing a significant increase in the rotational capacity of stainless-steel connections. This, in turn, may provide significant benefits for the overall response of a structure in terms of capacity and ductility. However, the bulk of the research on stainless-steel that has been published so far has mostly ignored the analysis of the deformation capabilities of the stainless-steel connections and has mostly focused on the structural response of individual members, such as beams or columns. For such a reason, the present study aims to contribute to the general understanding of the behaviour of stainless-steel connections from a conceptual, numerical and design standpoint. After a brief review of the available literature, the influence of the use of stainless-steel for column–beam connections is discussed from a theoretical standpoint. As a novel contribution, a different approach to compute the pseudo-plastic moment resistance that takes into account the post-elastic secant stiffness of the stainless-steel is proposed. Successively, a refined finite element model is employed to study the failure of stainless-steel column–beam connections. Finally, a critical assessment of the employment of carbon-steel-based design guidelines for stainless-steel connections provided by the Eurocode 3 design (EN 1993-1-8) is performed. The findings prove the need for the development of novel design approaches and more precise capacity models capable of capturing the actual stainless-steel joint response and their impact on the overall ductility and capacity of the whole structure

    Clinical outcomes of endurant II stent-graft for infrarenal aortic aneurysm repair: Comparison of on-label versus off-label use

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    PURPOSE We aimed to compare the outcomes of the Endurant II (Medtronic) stent-graft used under instructions for use versus off-label in high-risk patients considered unfit for conventional surgery. METHODS Data from patients treated with the Endurant II stent-graft between December 2012 and March 2015 were retrospectively analyzed. Sixty-four patients were included. Patients were assigned to group A if treated under instructions for use (n=34, 53%) and to group B if treated off-label (n=30, 47%). Outcome measures included perioperative mortality and morbidity, survival, freedom from reintervention, endoleak incidence, in-hospital length of stay, and mean stent-graft component used. Mean follow-up was 22.61±12 months (median, 21.06 months; range, 0–43 months). RESULTS One perioperative mortality (1.6%) and one perioperative complication (1.6%) occurred in group B. At two months follow-up, one iliac limb occlusion (1.6%) occurred in group A. No type I/III endoleaks were recorded. A type II endoleak was identified in three cases (4.7%). Overall survival at three years was 89% (97% for group A, 82% for group B; P = 0.428). Reintervention-free survival at three years was 97% for both groups (P = 0.991). A longer in-hospital stay was observed in group B (P = 0.012). CONCLUSION The Endurant II (Medtronic) new generation device was safe in off-label setting at mid-term follow-up. The off-label use of the Endurant II (Medtronic) is justified in patients considered unfit for conventional surgery. Larger studies are required in this subgroup of patients

    Post Thoracotomy Pain Syndrome

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