3,648 research outputs found

    Influence of Zn excess on compositional, structural and vibrational properties of Cu2ZnSn0.5Ge0.5Se4 thin films and their effect on solar cell efficiency

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    This Accepted Manuscript will be available for reuse under a CC BY-NC-ND licence after 24 months of embargo periodThe effect of Zn content on compositional, structural and vibrational properties of Cu2ZnSn1-xGexSe4 (CZTGSe, x ~ 0.5) thin films is studied. Kesterite layer is deposited by co-evaporation onto 5 × 5 cm2 Mo/SLG substrate followed by a thermal treatment at maximum temperature of 480 °C, obtaining areas with different composition and morphology which are due to the sample position in the co-evaporation system and to the non-uniform temperature distribution across the substrate. Kesterite layers with higher Zn amounts are characterized by lower Cu and Ge contents; however, a uniform Ge distribution through the absorber layer is detected in all cases. The excess Zn concentration leads to the formation of ZnSe secondary phase on the surface and in the bulk of the absorber as determined by Raman spectroscopy. When higher Ge content and no ZnSe are present in the absorber layer, a compact structure is formed with larger grain size of kesterite. This effect could explain the higher Voc of the solar cell. The Zn content does not affect the bandgap energy significantly (Eg near 1.3 eV), although the observed effect of Zn excess in CZTGSe results in a decreased device performance from 6.4 to 4.2%. This investigation reveals the importance of the control of the off-stoichiometric CZTGSe composition during the deposition process to enhance solar cells propertiesThis work was supported by Spanish Ministry of Science, Innovation and Universities Project WINCOST (ENE2016-80788-C5-2-R) and European Project INFINITE CELL (H2020-MSCA-RISE-2017-777968). ARP also acknowledges financial support from Community of Madrid within Youth Employment Program (PEJD-2017-PRE/IND-4062). MG acknowledges the financial support from ACCIÓ-Generalitat de Catalunya within the TECNIOspring Plus fellowship (TECSPR18-1-0048

    Late differentiation syndrome in acute promyelocytic leukemia: a challenging diagnosis

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    Detailed knowledge about differentiation syndrome (DS) has remained limited. There are 2 large studies conducted by the Spanish workgroup PETHEMA (Programa Español de Tratamientos en Hematología; Spanish Program on Hematology Treatments) and the European group trial (LPA 96-99 and APL 93) in which the incidence, characteristics, prognostic factors and outcome of patients developing DS are evaluated. Both have described the median time of DS development between 10 and 12 days. The severity of the DS has been evaluated in the study conducted by PETHEMA, and severe DS usually occurs at the beginning of the treatment (median of 6 days), as compared with moderate DS (median of 15 days). We report here in two cases of late severe DS, with late diagnosis due to both time and form of presentation. We discuss the physiopathology, clinical presentation, prophylaxis and treatment of DS

    Optimizing prolog for small devices: A case study

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    In this paper we present the design and implementation of a wearable application in Prolog. The application program is a "sound spatializer." Given an audio signal and real time data from a head-mounted compass, a signal is generated for stereo headphones that will appear to come from a position in space. We describe high-level and low-level optimizations and transformations that have been applied in order to fit this application on the wearable device. The end application operates comfortably in real-time on a wearable computer, and has a memory foot print that remains constant over time enabling it to run on continuous audio streams. Comparison with a version hand-written in C shows that the C version is no more than 20-40% faster; a small price to pay for a high level description

    High-level languages for small devices: A case study

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    In this paper we study, through a concrete case, the feasibility of using a high-level, general-purpose logic language in the design and implementation of applications targeting wearable computers. The case study is a "sound spatializer" which, given real-time signáis for monaural audio and heading, generates stereo sound which appears to come from a position in space. The use of advanced compile-time transformations and optimizations made it possible to execute code written in a clear style without efñciency or architectural concerns on the target device, while meeting strict existing time and memory constraints. The final executable compares favorably with a similar implementation written in C. We believe that this case is representative of a wider class of common pervasive computing applications, and that the techniques we show here can be put to good use in a range of scenarios. This points to the possibility of applying high-level languages, with their associated flexibility, conciseness, ability to be automatically parallelized, sophisticated compile-time tools for analysis and verification, etc., to the embedded systems field without paying an unnecessary performance penalty

    Control de calidad del seguimiento del embarazo normal en atención primaria

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    ObjetivosGeneral: aumentar la calidad de la atención maternoinfantil en nuestra población.Específicomejorar al menos un 10% el registro de las actividades con peor cumplimiento en la primera evaluación del ciclo de calidad.DiseñoCiclo de calidad del programa de seguimiento de embarazo normal en atención primaria (AP).Dimensión de calidad estudiadacientífico-técnica. Evaluación retrospectiva, cruzada, por iniciativa interna y sobre las historias clínicas de las gestantes. Marco temporal: primera evaluación sobre gestaciones de 1994-1995; aplicación de medidas correctoras durante 1996; segunda evaluación sobre gestaciones de 1997-1998.ÁmbitoAtención primaria.SujetosTodas las gestaciones seguidas en nuestro equipo de AP durante los períodos descritos.Mediciones y resultados principalesCriterios evaluados: actividades asistenciales del programa de seguimiento del embarazo normal del Área 10.Primera evaluación (n = 54)incumplimiento global del 11,5%; los criterios con cumplimiento inferior al 80% fueron suplemento con ácido fólico, consejos a la gestante, detección de diabetes gestacional y visita al mes posparto Segunda evaluación (n = 69) incumplimiento global del 6,3%; todas las actividades superaron el 80% excepto la exploración obstétrica en la primera visita, la visita a la semana posparto y la visita al mes posparto.ConclusionesTras la introducción de unas medidas correctoras sencillas, logramos una mejoría global superior al 40% y un aumento en el cumplimiento de la mayor parte de las actividades, excepto en las visitas posparto y la exploración obstétrica en la primera visita. Creemos que es necesario mantener un ciclo continuo de mejora de calidad para conseguir una adecuada asistencia maternoinfantil.ObjectivesGeneral: to increase the quality of mother-baby care in our population. Specific: to improve by at least 10% the record of activities with poorest compliance at the first evaluation on the quality cycle.DesignQuality cycle of the normal pregnancy monitoring programme in primary care (PC). The scientific-technical dimension of quality was the one studied. There was a retrospective, crossed evaluation, on internal initiative, about the clinical records of the pregnant women. Sequence: first evaluation of pregnancies in 1994-95; application of corrective measures in 1996; second evaluation of pregnancies in 1997-98.SettingPrimary care.PatientsAll the pregnancies monitored by our PC team during the periods described.Measurements and main resultsCriteria evaluated: care activities of the programme for monitoring normal pregnancies in Area 10. First evaluation (n = 54): 11.5% overall non-compliance. The criteria with under 80% compliance were: folic acid supplement, counselling, diagnosis of pregnancy diabetes and attendance in the month after delivery. Second evaluation (n = 69): 6.3% overall non-compliance. All activities surpassed 80% compliance except obstetric examination on the first visit, attendance a week after delivery and attendance a month after delivery.ConclusionsAfter introducing certain simple corrective measures, we achieved overall improvement of over 40% and increased compliance in most activities, except for attendance after delivery and obstetric examination on the first visit. We think a continuous cycle of quality improvement needs to be maintained in order to achieve adequate mother-baby care

    Revisiting the method to obtain the mechanical properties of hydrided fuel cladding in the hoop direction

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    The method reported in the literature to calculate the stress–strain curve of nuclear fuel cladding from ring tensile test is revisited in this paper and a new alternative is presented. In the former method, two universal curves are introduced under the assumption of small strain. In this paper it is shown that these curves are not universal, but material-dependent if geometric nonlinearity is taken into account. The new method is valid beyond small strains, takes geometric nonlinearity into consideration and does not need universal curves. The stress–strain curves in the hoop direction are determined by combining numerical calculations with experimental results in a convergent loop. To this end, ring tensile tests were performed in unirradiated hydrogen-charged samples. The agreement among the simulations and the experimental results is excellent for the range of concentrations tested (up to 2000 wppm hydrogen). The calculated stress–strain curves show that the mechanical properties do not depend strongly on the hydrogen concentration, and that no noticeable strain hardening occurs. However, ductility decreases with the hydrogen concentration, especially beyond 500 wppm hydrogen. The fractographic results indicate that as-received samples fail in a ductile fashion, whereas quasicleavage is bserved in the hydrogen-charged samples

    SHARDS: Constraints on the dust attenuation law of star-forming galaxies at z~2

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    We make use of SHARDS, an ultra-deep (<26.5AB) galaxy survey that provides optical photo-spectra at resolution R~50, via medium band filters (FWHM~150A). This dataset is combined with ancillary optical and NIR fluxes to constrain the dust attenuation law in the rest-frame NUV region of star-forming galaxies within the redshift window 1.5<z<3. We focus on the NUV bump strength (B) and the total-to-selective extinction ratio (Rv), targeting a sample of 1,753 galaxies. By comparing the data with a set of population synthesis models coupled to a parametric dust attenuation law, we constrain Rv and B, as well as the colour excess, E(B-V). We find a correlation between Rv and B, that can be interpreted either as a result of the grain size distribution, or a variation of the dust geometry among galaxies. According to the former, small dust grains are associated with a stronger NUV bump. The latter would lead to a range of clumpiness in the distribution of dust within the interstellar medium of star-forming galaxies. The observed wide range of NUV bump strengths can lead to a systematic in the interpretation of the UV slope (β\beta) typically used to characterize the dust content. In this study we quantify these variations, concluding that the effects are Δβ\Delta\beta~0.4.Comment: 13 pages, 11+2 figures, 3 tables. MNRAS, in pres

    Geoelectrical and electromagnetic methods applied to paleolimnological studies: Two examples from desiccated lakes in the Basin of Mexico

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    Paleolimnological studies require a broad understanding of the geometry and depth of the sedimentary fill of lake basins prior to coring campaigns. Seismic methods are routinely employed for the indirect characterization of lake-bottom sediments. However, the use of seismic methods might occasionally be limited due to surface conditions or poor seismic contrasts between the stratigraphic units, which lead to data quality that is too poor to provide sufficient information for the selection of drill sites. Sources of cultural noise are one of the main reasons why seismic methods fail in study areas near or within large cities, such as Mexico City. Under certain conditions, electrical and electromagnetic methods might be a suitable substitute or complement to seismic exploration, as they respond to different physical properties of the subsurface. To evaluate the applicability of such methods, here we present two recent case studies from the desiccated lakes Chalco and Xochimilco both located in urban areas within the Basin of Mexico where electrical resistivity tomography (ERT), transient electromagnetic (TEM) and magnetotelluric (MT) soundings were conducted for the characterization of lake basement and lacustrine sediments. In both examples, the results of the geophysical exploration contributed valuable stratigraphic information for the following drilling and core recovery, which highlights the potential of electrical and electromagnetic methods in paleolimnological studies

    Beef from Calves Finished with a Diet Based on Concentrate Rich in Agro-Industrial By-Products: Acceptability and Quality Label Preferences in Spanish Meat Consumers

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    Conjoint analysis was used to estimate the relative importance of some of the main extrinsic attributes and quality labels of beef in three Spanish cities (Córdoba, Marbella, and Santa Pola) in a study performed with 300 individuals. Consumers were segmented according to their frequency of consumption. Willingness to pay for different meats was also calculated from the conjoint analysis results. Consumer liking of beef that had been finished with an alternative concentrate rich in agro-industrial by-products and aged for three different durations as compared to conventionally finished beef was also evaluated using the same consumers. The most important attribute for Spanish consumers was the price (28%), followed by origin (25%), animal welfare certification (19%), protected geographical indication (14%), and organic agriculture certification (14%). Most consumers preferred beef from Spain at the lowest possible price and with the highest number of quality labels. Consumers were willing to pay a premium of 1.49, 3.61, and 5.53 EUR over 14 EUR/kg for organic certification, protected geographical indication, and animal welfare certification, respectively. Sensory analysis revealed that, for regular consumers, beef finished with an alternative concentrate rich in agro-industrial by-products offered several hedonic advantages (color, flavor, and tenderness) when compared to beef finished using a conventional diet, while occasional consumers did not find any difference between the two kinds of meat

    The action of obestatin in skeletal muscle repair: stem cell expansion, muscle growth, and microenvironment remodeling

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    The development of therapeutic strategies for skeletal muscle diseases, such as physical injuries and myopathies, depends on the knowledge of regulatory signals that control the myogenic process. The obestatin/GPR39 system operates as an autocrine signal in the regulation of skeletal myogenesis. Using a mouse model of skeletal muscle regeneration after injury and several cellular strategies, we explored the potential use of obestatin as a therapeutic agent for the treatment of trauma-induced muscle injuries. Our results evidenced that the overexpression of the preproghrelin, and thus obestatin, and GPR39 in skeletal muscle increased regeneration after muscle injury. More importantly, the intramuscular injection of obestatin significantly enhanced muscle regeneration by simulating satellite stem cell expansion as well as myofiber hypertrophy through a kinase hierarchy. Added to the myogenic action, the obestatin administration resulted in an increased expression of VEGF/VEGFR2 and the consequent microvascularization, with no effect on collagen deposition in skeletal muscle. Furthermore, the potential inhibition of myostatin during obestatin treatment might contribute to its myogenic action improving muscle growth and regeneration. Taken together, our data demonstrate successful improvement of muscle regeneration, indicating obestatin is a potential therapeutic agent for skeletal muscle injury and would benefit other myopathies related to muscle regeneration
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