364 research outputs found

    Complementing Farmers' Genetic Knowledge Farmer Breeding Workshop in Turipaná, Colombia

    Get PDF
    This workshop explored the feasibility and methods for complementing farmer experts' knowledge and skills in the enhancement and conservation of agrobiodiversity

    Gains from selection to improve carotenoids content in cassava roots

    Get PDF

    Plan de negocios para un colegio biling?e como una nueva unidad estrat?gica de negocios del Instituto Cultural Peruano Norteamericano - ICPNA

    Get PDF
    La tesis que se presenta a continuaci?n, es el plan de negocio para un colegio Biling?e como una nueva unidad estrat?gica de negocios del instituto cultural peruano norteamericano ? ICPNA. El objetivo es determinar la viabilidad comercial y econ?mica de la implementaci?n de un colegio biling?e en una de las sedes del ICPNA, aprovechando la capacidad ociosa del ICPNA y ante la creciente tasa de poblaci?n estudiantil en Lima. Se har? uso de uno de las edificaciones m?s modernas con las que cuenta el instituto, adem?s de la tecnolog?a y ?reas adecuadas para la correcta ense?anza de educaci?n inicial, primaria (hasta 3er grado). Bajo el posicionamiento que tiene el ICPNA, se realiz? una evaluaci?n a fin de conocer las necesidades de los padres de familia para la ense?anza a nivel escolar, de sus hijos. Destacando la gran iniciativa del ICPNA, pues no solo ayudar? a que se formen en las materias dentro de una estructura curricular adecuada y conforme a las normas del ministerio de educaci?n, sino que adem?s puedan contar con un soporte adecuado de un segundo idioma tan necesario en el presente y para el futuro profesional

    Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: polarization dependence, selection rules and strain effects

    Get PDF
    Polarization dependent Raman scattering experiments realized on single GaAs nanowires with different percentages of zinc-blende and wurtzite structure are presented. The selection rules for the special case of nanowires are found and discussed. In the case of zinc-blende, the transversal optical mode E1(TO) at 267 cm-1 exhibits the highest intensity when the incident and analyzed polarization are parallel to the nanowire axis. This is a consequence of the nanowire geometry and dielectric mismatch with the environment, and in quite good agreement with the Raman selection rules. We also find a consistent splitting of 1 cm-1 of the E1(TO). The transversal optical mode related to the wurtzite structure, E2H, is measured between 254 and 256 cm-1, depending on the wurtzite content. The azymutal dependence of E2H indicates that the mode is excited with the highest efficiency when the incident and analyzed polarization are perpendicular to the nanowire axis, in agreement with the selection rules. The presence of strain between wurtzite and zinc-blende is analyzed by the relative shift of the E1(TO) and E2H modes. Finally, the influence of the surface roughness in the intensity of the longitudinal optical mode on {110} facets is presented.Comment: 28 pages, 12 figures. to be published in Phys. Rev.

    Mejoramiento genético de la yuca

    Get PDF

    Structural and optical properties of high quality zinc-blende/wurtzite GaAs hetero-nanowires

    Get PDF
    The structural and optical properties of 3 different kinds of GaAs nanowires with 100% zinc-blende structure and with an average of 30% and 70% wurtzite are presented. A variety of shorter and longer segments of zinc-blende or wurtzite crystal phases are observed by transmission electron microscopy in the nanowires. Sharp photoluminescence lines are observed with emission energies tuned from 1.515 eV down to 1.43 eV when the percentage of wurtzite is increased. The downward shift of the emission peaks can be understood by carrier confinement at the interfaces, in quantum wells and in random short period superlattices existent in these nanowires, assuming a staggered band-offset between wurtzite and zinc-blende GaAs. The latter is confirmed also by time resolved measurements. The extremely local nature of these optical transitions is evidenced also by cathodoluminescence measurements. Raman spectroscopy on single wires shows different strain conditions, depending on the wurtzite content which affects also the band alignments. Finally, the occurrence of the two crystallographic phases is discussed in thermodynamic terms.Comment: 24 page

    Complement component 3 (C3) expression in the hippocampus after excitotoxic injury: role of C/EBPβ

    Get PDF
    [Background] The CCAAT/enhancer-binding protein β (C/EBPβ) is a transcription factor implicated in the control of proliferation, differentiation, and inflammatory processes mainly in adipose tissue and liver; although more recent results have revealed an important role for this transcription factor in the brain. Previous studies from our laboratory indicated that CCAAT/enhancer-binding protein β is implicated in inflammatory process and brain injury, since mice lacking this gene were less susceptible to kainic acid-induced injury. More recently, we have shown that the complement component 3 gene (C3) is a downstream target of CCAAT/enhancer-binding protein β and it could be a mediator of the proinflammatory effects of this transcription factor in neural cells.[Methods] Adult male Wistar rats (8–12 weeks old) were used throughout the study. C/EBPβ+/+ and C/EBPβ–/– mice were generated from heterozygous breeding pairs. Animals were injected or not with kainic acid, brains removed, and brain slices containing the hippocampus analyzed for the expression of both CCAAT/enhancer-binding protein β and C3.[Results] In the present work, we have further extended these studies and show that CCAAT/enhancer-binding protein β and C3 co-express in the CA1 and CA3 regions of the hippocampus after an excitotoxic injury. Studies using CCAAT/enhancer-binding protein β knockout mice demonstrate a marked reduction in C3 expression after kainic acid injection in these animals, suggesting that indeed this protein is regulated by C/EBPβ in the hippocampus in vivo.[Conclusions] Altogether these results suggest that CCAAT/enhancer-binding protein β could regulate brain disorders, in which excitotoxic and inflammatory processes are involved, at least in part through the direct regulation of C3.This work was supported by MINECO, Grant SAF2014-52940-R and partially financed with FEDER funds. CIBERNED is funded by the Instituto de Salud Carlos III. JAM-G was supported by CIBERNED. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

    Moderate alcohol consumption increases insulin sensitivity and ADIPOQ expression in postmenopausal women: a randomised, crossover trial

    Get PDF
    Aims/hypothesis To determine whether 6 weeks of daily, moderate alcohol consumption increases expression of the gene encoding adiponectin (ADIPOQ) and plasma levels of the protein, and improves insulin sensitivity in postmenopausal women. Methods In a randomised, open-label, crossover trial conducted in the Netherlands, 36 apparently healthy postmenopausal women who were habitual alcohol consumers, received 250 ml white wine (~25 g alcohol/day) or 250 ml of white grape juice (control) daily during dinner for 6 weeks. Randomisation to treatment allocation occurred according to BMI. Insulin sensitivity and ADIPOQ mRNA and plasma adiponectin levels were measured at the end of both periods. Insulin sensitivity was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). Levels of ADIPOQ mRNA in subcutaneous adipose tissue were determined by RT-PCR. Results All subjects completed the study. Six weeks of white wine consumption reduced fasting insulin (mean¿±¿SEM 40.0¿±¿3.4 vs 46.5¿±¿3.4 pmol/l; p
    • …
    corecore