Origin of the negative differential resistance in the output characteristics of a picene-based thin-film transistor

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this work, we have fabricated and studied p-type picene thin-film transistors. Although the devices exhibited good electrical performance with high field-effect mobility (up to 1.3 cm2/V¿s) and on/off ratios above 105, the output electric characteristics of the devices exhibited a Negative Differential Resistance for higher drain-source voltage. Finally, a possible explanation for this phenomenon is developed.Peer ReviewedPostprint (author's final draft

Contrasting growth and water use strategies in four co-occurring Mediterranean tree species revealed by concurrent measurements of sap flow and stem diameter variations

Drought limits tree water use and growth of Mediterranean trees. However, growth and water use strate-gies are rarely addressed simultaneously across species and drought conditions. Here, we investigatethe link between stem diameter variations and sap flow in four co-existing Mediterranean trees (Pinushalepensis Mill., Quercus pubescens Willd., Quercus ilex L. and Arbutus unedo L.), under relatively wet (2011)and dry (2012) conditions. Continuous stem diameter variations were converted to basal area increment(BAI) and de-trended to estimate tree water deficit ( W), an indicator of stem hydration. P. halepensis andQ. pubescens showed the most and the least conservative sap flow density (JS) regulation under drought,respectively, with Q. ilex and A.unedo showing intermediate drought responses. All species, except A.unedo, showed some between-year variability in the environmental control of JS. Seasonal stem shrink-age in response to drought (i.e., increasing W) and subsequent trunk rehydration after rainfall (i.e.,decreasing W) occurred in all species. Vapor pressure deficit (VPD) and soil moisture ( ) interacted todetermine seasonal variation in W. Interestingly, in the dry year, 2012, more species-specific differ-ences were found in the responses of W to and VPD. Across species, JSand W began to decline atsimilar soil moisture thresholds, underpinning the tight link between JSand W under varying droughtconditions. Annual BAI decreased proportionally more than tree-level transpiration (JT) between the wet(2011) and the dry (2012) year, hence growth-based WUE (WUEBAI= BAI/JT) decreased for all species,albeit less acutely for P. halepensis. Overall, despite their contrasting leaf habit and wood type, the stud-ied Mediterranean tree species show coordinated responses of transpiration, water storage dynamicsand growth-based WUE which allow them to cope with seasonal and interannual drought

Effect of Natural Antioxidants on the Oxidative Stability of Eggs

Due to the increase in the production of co3 PUFA enriched eggs, prevention of lipid oxidation in such products became more important. Dietary supplementation with alpha-tocopherol has been reported to increase the oxidative stability of animal products (Lauridsen et al. 1997, Cherian et al. 1996)

On the halide hydration study: Development of first-principles halide ion-water interaction potential based on a polarizable model

The development of first-principles halide-water interaction potentials for fluoride and iodide anions is presented. The model adopted is the mobile charge densities in harmonic oscillator that allows for a flexible and polarizable character of the interacting particles. The set of points of the quantum mechanical potential energy surfaces are calculated up to the MP2 level. The nonadditive many-body contributions were included explicitly at the three-body terms. Structural and energetic properties of the [ X(H2O)n ]- clusters (n=1 – 6) are studied with the new interaction potentials developed. Halide aqueous solutions are also studied by means of Monte Carlo simulations. The agreement between experimental and our predicted estimations shows the good behavior of the proposed potentials. The developed potentials are able to properly describe both the microsolvation of clusters in gas phase and their hydration in aqueous solutions. The different nature of the interactions among F-, Br-, I- and water appears in the set of studied properties, thus giving a gradual change in the behavior along the group.Dirección General de Investigaciones Científicas y Técnicas BQU2002-0221

La Enseñanza de las Matemáticas en la E.U. de Informática

El Departamento de Matemática Aplicada (E. U. Informática) de la Universidad Politécnica de Madrid tiene a su cargo la docencia de todas las asignaturas de matemáticas de las titulaciones de I.T.I. de Sistemas y de I.T.I. de gestión, implantadas en el curso 1992-93. Asignaturas troncales: Álgebra, Análisis matemático y métodos numéricos, Matemática discreta y estadística. Asignaturas optativas o de libre elección: Laboratorio de matemáticas, Lógica, Métodos de cálculo científico, Geometría computacional, Investigación operativa (Sistemas), investigación operativa (gestión), geometría computacional avanzada y Tratamiento estadístico de datos con ordenador. Un denominador común en todas las asignaturas es la realización de prácticas con ordenador. En las clases prácticas el papel de los estudiantes es más activo y pensamos que Éste es un factor positivo para el aprendizaje. Otro aspecto contemplado en todas las asignaturas es el de facilitar al alumno un material de trabajo adecuado, con la posibilidad de contar desde el principio de curso con información suficiente sobre los contenidos, bibliografía, metodología y normas de evaluación, así como con los enunciados de problemas y prácticas que se irán abordando a lo largo del curso. También se les facilita información sobre exámenes de cursos anteriores. En la ponencia se comentan algunos detalles sobre la planificación de las asignaturas troncales

Back junction n-type silicon heterojunction solar cells with V2O5 hole-selective contact

Postprint (published version

Cannabigerol action at cannabinoid CB1 and CB2 receptors and at CB1-CB2 heteroreceptor complexes

Cannabigerol (CBG) is one of the major phytocannabinoids present in Cannabis sativa L. that is attracting pharmacological interest because it is non-psychotropic and is abundant in some industrial hemp varieties. The aim of this work was to investigate in parallel the binding properties of CBG to cannabinoid CB1 (CB1R) and CB2 (CB2R) receptors and the effects of the compound on agonist activation of those receptors and of CB1-CB2 heteroreceptor complexes. Using [3H]-CP-55940, CBG competed with low micromolar Ki values the binding to CB1R and CB2R. Homogeneous binding in living cells, which is only possible for the CB2R, provided a nanomolar Ki value. In contrast, CBG competed the binding of [3H]-WIN-55,212-2 to CB2R but not to CB1R (2.7 versus >30 µM). The phytocannabinoid modulated signaling mediated by receptors and receptor heteromers even at low concentrations of 0.1-1 µM. cAMP, pERK, ÿ-arrestin recruitment and label-free assays in HEK-293T cells expressing the receptors and treated with endocannabinoids or selective agonists proved that CBG is a partial agonist of CB2R. The action on cells expressing heteromers was similar to that obtained in cells expressing the CB2R. The effect of CBG on CB1R was measurable but the underlying molecular mechanisms remain uncertain. The results indicate that CBG is indeed effective as regulator of endocannabinoid signaling