Curriculum and teaching: what and how student at risk are thought?

En el presente artículo se analiza el currículo y la enseñanza de dos programas o medidas que se desarrollan en la Región de Murcia y en la Comunidad de Andalucía –Programa de Diversificación Curricular y Programa de Iniciación Profesional y/o Programa de Garantía Social- ambos destinados al alumnado con serias dificultades para continuar la enseñanza en las aulas regulares. Tras presentar diversos datos recogidos a través de cuestionarios y entrevistas con diferentes sujetos implicados, se analizan y valoran los resultados de la investigación realizada, procurando responder a la cuestión de en que grado el currículo diseñado en tales programas y la formación y aprendizajes logrados han contribuido a responder a las necesidades de este alumnadoThe article analyses curriculum and teaching of two programs in the Region of Murcia and in the Community of Andalusia - Program of Diversification Curricular and Program of Professional Initiation and / or Program of Social Guarantee – designed and implemented with students at risks, in serious difficulties to progress their learning in regular classrooms and teaching. After presenting different data gathered throw questionnaires and interviews carried out with different teachers, the outcomes are analyzed and valued in order to answer the question related to the degree in which de curriculum designed and its implementation in such programs respond properly to students needs and contributed to theirs expected learnin

HTLV-1 infection in solid organ transplant donors and recipients in Spain

HTLV-1 infection is a neglected disease, despite infecting 10-15 million people worldwide and severe illnesses develop in 10% of carriers lifelong. Acknowledging a greater risk for developing HTLV-1 associated illnesses due to immunosuppression, screening is being widely considered in the transplantation setting. Herein, we report the experience with universal HTLV testing of donors and recipients of solid organ transplants in a survey conducted in Spain. All hospitals belonging to the Spanish HTLV network were invited to participate in the study. Briefly, HTLV antibody screening was performed retrospectively in all specimens collected from solid organ donors and recipients attended since the year 2008. A total of 5751 individuals were tested for HTLV antibodies at 8 sites. Donors represented 2312 (42.2%), of whom 17 (0.3%) were living kidney donors. The remaining 3439 (59.8%) were recipients. Spaniards represented nearly 80%. Overall, 9 individuals (0.16%) were initially reactive for HTLV antibodies. Six were donors and 3 were recipients. Using confirmatory tests, HTLV-1 could be confirmed in only two donors, one Spaniard and another from Colombia. Both kidneys of the Spaniard were inadvertently transplanted. Subacute myelopathy developed within 1 year in one recipient. The second recipient seroconverted for HTLV-1 but the kidney had to be removed soon due to rejection. Immunosuppression was stopped and 3 years later the patient remains in dialysis but otherwise asymptomatic. The rate of HTLV-1 is low but not negligible in donors/recipients of solid organ transplants in Spain. Universal HTLV screening should be recommended in all donor and recipients of solid organ transplantation in Spain. Evidence is overwhelming for very high virus transmission and increased risk along with the rapid development of subacute myelopathy

Effect of the bridge substitution on the efficiency of dye-sensitized solar cells

We have designed and synthesized a novel D–π–A dye based on zinc porphyrin as the donor, cyanoacrylic acid as the acceptor and trans-bis(3,4-ethylenedioxythiophene)vinylene as the bridge. Under standard global AM 1.5 solar conditions, the Zn-porphyrin-2-EDOT sensitizer based cell gave a JSC of 7.28 mA cm−2, VOC of 0.438 V was obtained with a FF of 0.514, corresponding to an overall conversion efficiency η = 1.64%. The reasons for this low efficiency are analyzed to try to develop knowledge for future dye designing

Origin of efficiency enhancement in Nb2O5 coated titanium dioxide nanorod based dye sensitized solar cells

[EN] Ordered one-dimensional metal oxides are considered promising architectures for dye-sensitized solar cells (DSC). Here we explore the properties determining the photovoltaic performance of DSC based on titanium dioxide nanorods prepared by a hydrothermal method. Ultrathin conformal coating with other oxides such as Al2O3 or Nb2O5 has been widely used in the literature to improve the conversion efficiency. Usually the effects attributed to the coating are either to prevent recombination by barrier effect or to change the position of titanium dioxide conduction band. Here we show that coating TiO2 nanorods with Nb2O5 increases the photocurrent and conversion efficiency of the DSC. However, impedance spectroscopy results indicate that neither recombination is reduced by the coating nor the conduction band position is moved. The improvement in the performance of the cell has been attributed to an enhancement in the charge injection efficiency promoted by Nb2O5.We are thankful for financial support from Ministerio de Ciencia e Innovacion under Projects HOPE CSD2007-00007 and MAT 2010-19827, Generalitat Valenciana under Project PROM-ETEO/2009/058 and Programa de Mobilidad del Personal Investigador de Bancaixa. Servei Central d'Instrumentacio Cientifica of Universitat Jaume I is acknowledged for the SEM and TEM measurements, and Sixto Gimenez for fruitful discussions.Barea, EM.; Xu, X.; González-Pedro, V.; Ripolles-Sanchis, T.; Fabregat-Santiago, F.; Bisquert Mascarell, J. (2011). Origin of efficiency enhancement in Nb2O5 coated titanium dioxide nanorod based dye sensitized solar cells. Energy and Environmental Science. 4(9):3414-3419. https://doi.org/10.1039/c1ee01193fS341434194

Origin of efficiency enhancement in Nb2O5 coated titanium dioxide nanorod based dye sensitized solar cells

Ordered one-dimensional metal oxides are considered promising architectures for dye-sensitized solar cells (DSC). Here we explore the properties determining the photovoltaic performance of DSC based on titanium dioxide nanorods prepared by a hydrothermal method. Ultrathin conformal coating with other oxides such as Al2O3 or Nb2O5 has been widely used in the literature to improve the conversion efficiency. Usually the effects attributed to the coating are either to prevent recombination by barrier effect or to change the position of titanium dioxide conduction band. Here we show that coating TiO2 nanorods with Nb2O5 increases the photocurrent and conversion efficiency of the DSC. However, impedance spectroscopy results indicate that neither recombination is reduced by the coating nor the conduction band position is moved. The improvement in the performance of the cell has been attributed to an enhancement in the charge injection efficiency promoted by Nb2O5

Panchromatic Solar-to-H2 Conversion by a Hybrid Quantum Dots-Dye Dual Absorber Tandem Device

Solution-processed mesoscopic oxide semiconductor-based materials offer potentially low-cost and high stability alternative for next generation of water to hydrogen conversion photoelectrochemical cells (PEC). In the present study, we demonstrate the effective unassisted H2 generation by a tandem device based on a quantum dot (QD)-dye dual absorber system. These systems are constituted by a TiO2 mesoscopic photoanode sensitized with CdS QDs and a dye sensitized solar cell (DSSC), based on ruthenium dye, connected in series. This solar cell supplies the needed photovoltage to induce photodriven hydrogen production. Opto-electrochemical characterization of the single components allows the prediction of the operational photocurrents and a reliable estimation of the theoretical power conversion efficiencies of tandem systems. Evolved hydrogen under simulated solar illumination was collected, and solar to hydrogen conversion efficiencies (STH) were obtained. The tandem devices have demonstrated high stability in aqueous medium and solar-to-hydrogen conversion efficiency of (0.78 ± 0.04)%, near tripling the efficiency of single QD based photoanodes. These results highlight the importance of the design of hybrid photoanodes combining the effect of different light absorbers working in parallel tandem devices for the development of efficient H2 generation QD-based photoelectrochemical cells. © 2013 American Chemical Society

Organo-metal halide perovskite-based solar cells with CuSCN as the inorganic hole selective contact

CuSCN is proposed as a cost-competitive hole selective contact for the emerging organo-metal halide perovskite-based solar cells. The CuSCN films have been deposited by a solution casting technique, which has proven to be compatible with the perovskite films, obtaining planar-like heterojunction-based glass/FTO/TiO2/CH3NH3PbI3−xClx/CuSCN/Au solar cells with a power conversion efficiency of 6.4%. Among the photovoltaic parameters, the fill factor (i.e. 62%) suggests good carrier selectivity and, therefore, efficient functionality of the TiO2 and CuSCN charge carrier selective contacts. However, the open-circuit voltage (Voc), which remains low in comparison with the state of the art perovskite-based solar cells, appears to be the main limiting parameter. This is attributed to the short diffusion length as determined by impedance spectroscopy. However, the recombination losses are not only affected by the CuSCN, but also by the perovskite film. Indeed, variations of 20 °C in the thermal annealing of the perovskite films result in changes larger than 200 mV in the Voc. Furthermore, a detailed analysis of the quantum efficiency spectra contributes significant insights into the influence of the selective contacts on the photocurrent of the planar heterojunction perovskite solar cells

Porphyrin Dyes with High Injection and Low Recombination for Highly Efficient Mesoscopic Dye-Sensitized Solar Cells

The photovoltaic performance and charge recombination characteristics of porphyrin-based dye-sensitized solar cell (DSC) devices have been investigated using the impedance spectroscopy (IS) technique. The IS results provide key information related to the device performance for a highly efficient porphyrin dye (YD2), a reference porphyrin dye (YD0), and a commercial ruthenium dye (N719). The DSC devices constructed using YD2 and N719 dyes reach similar internal power conversion efficiencies (7.41% vs 7.54%) due to the higher injection of the YD2 dye that is compromised by a lower photovoltage. In addition, both YD2 and N719 dyes exhibit the same charge-transfer resistance, indicating that the recombination rates of both dyes are very similar. The diarylamino group plays a key role to repel the triiodide ions from the titania surface so that the charge recombination of YD2 is less significant compared with that of YD0