Ionic charging by local imbalance at interfaces in hybrid lead halide perovskites

Identification of specific operating mechanisms becomes particularly challenging when mixed ionic-electronic conductors are used in optoelectronic devices. Ionic effects in perovskitesolar cells are believed to distort operation curves and possess serious doubts about their long term stability. Current hysteresis and switchable photovoltaic characteristics have been connected to the kinetics of ion migration. However, the nature of the specific ionic mechanism (or mechanisms) able to explain the operation distortions is still poorly understood. It is observed here that the local rearrangement of ions at the electrodeinterfaces gives rise to commonly observed capacitive effects. Charging transients in response to step voltage stimuli using thick CH3NH3PbI3 samples show two main polarization processes and reveal the structure of the ionic double-layer at the interface with the non-reacting contacts. It is observed that ionic charging, with a typical response time of 10 s, is a local effect confined in the vicinity of the electrode, which entails absence of net mobile ionic concentration (space-charge) in the material bulk.We thank financial support from MINECO of Spain under Project (MAT2013-47192-C3-1-R), and Generalitat Valenciana (Prometeo/2014/020). O.A. acknowledges Generalitat Valenciana for a Grant (GRISOLIAP2014/035)

Motivations of the University s tudents in the physical and sports practice of free time. The nautical activities

El estudio de los perfiles motivacionales proporciona información detallada sobre los hábitos de los grupos de personas hacia la práctica de la actividad física, permitiendo poder fomentar una motivación más positiva y conseguir una mayor adherencia a la práctica. Así el objetivo de este estudio ha sido clarificar cuáles son las motivaciones frente a la práctica de actividad físico -deportiva de una muestra de jóvenes universitarios, incidiendo especialmente en las actividades náuticas. La muestra estuvo compuesta por 1011 estudiantes de la Universidad de Almería (España). El instrumento utilizado fue el cuestionario de hábitos físicos -deportivos y de práctica de deportes náuticos . Los resultados obtenidos apuntan que los principales motivos para desarrollar la práctica deportiva fueron la flexibilidad horaria y una adecuada a la disponibilidad de su tiempo libre, seguido de la cercanía a su domicilio de las instalaciones. Otros motivos son por diversión, o estar con su grupo de amigos. Respecto a las actividades náuticas, se decide practicar o no sólo porque les gustan, seguido del interés por estar en contacto con el medio natural y acuático. Las modalidades náuticas más practicadas son el piragüismo y la natación. En relación al abandono de la práctica deportiva, claramente se produce por la falta de tiempo por el estudio o el trabajo. Es evidente que la falta de tiempo por los estudios o por el trabajo, perjudica gravemente la adherencia a la actividad física, pero existen porcentajes muy altos de personas (62%) que admiten no practicar por pereza y desgana, por lo que se deben buscar nuevas estra tegias de motivación para que aumente la adherencia a la actividad físico deportiva

Effect of integrated fertilization and cover cropping on N2O losses in an irrigated mediterranean maize field

Agronomical and environmental benefits are associated with replacing winter fallow by cover crops (CC). Yet, the effect of this practice on nitrous oxide (N2 O) emissions remains poorly understood. The objective of this study was to evaluate the effect of two different CC species (barley and vetch) and fallow on N2O emissions during the CC period and during the following maize cash crop period in an Integrated Soil Fertility management (ISFM) system. We also aimed to study the contribution of synthetic fertilizer and other N sources to N2O emissions through a parallel 15N labelled fertilizer experiment

Medical Image Retrieval using Bag of Meaningful Visual Words: Unsupervised visual vocabulary pruning with PLSA

Content--based medical image retrieval has been proposed as a technique that allows not only for easy access to images from the relevant literature and electronic health records but also for training physicians, for research and clinical decision support. The bag-of-visual-words approach is a widely used technique that tries to shorten the semantic gap by learning meaningful features from the dataset and describing documents and images in terms of the histogram of these features. Visual vocabularies are often redundant, over--complete and noisy. Larger than required vocabularies lead to high--dimensional feature spaces, which present important disadvantages with the curse of dimensionality and computational cost being the most obvious ones. In this work a visual vocabulary pruning technique is presented. It enormously reduces the amount of required words to describe a medical image dataset with no significant effect on the accuracy. Results show that a reduction of up to 90% can be achieved without impact on the system performance. Obtaining a more compact representation of a document enables multimodal description as well as using classifiers requiring low--dimensional representations

Influence of Tillage and Liming on N2O emission from a rainfed crop

Nitrous oxide (N2O) is the main greenhouse gas (GHG) produced by agricultural soils due to microbial processes. The application of N fertilizers is associated with an increase of N2O losses. However, it is possible to mitigate these emissions by the introduction of adequate management practices (Snyder et al., 2009). Soil conservation practices (i.e.no tillage, NT) have recently become widespread because they promote several positive effects (increases in soil organic carbonand soil fertility, reduction of soil erosion, etc). In terms of GHG emissions, there is no consensus in the literature on the effects of tillage on N2O. Several studies found that NT can produce greater (Baggs et al., 2003), lower (Malhi et al., 2006) or similar (Grandey et al., 2006) N2O emissions compared to traditional tillage (TT). This large uncertainty is associated with the duration of tillage practices and climatic variability. Liming is widely use to solve problems of soil acidity (Al toxicity, yield penalties, etc). Several studies show a decrease in N2O emissions with liming (Barton et al., 2013) whereas no significant effects or increases were observed in others (Galbally et al., 2010). The aim of this work was to evaluate the effects of tillage (NT vs TT) and liming application or not of Ca-amendment) on N2O emissions from an acid soil during a rainfed crop

Fertilización y N2O. Implicaciones en la huella de carbono.

Todos los alimentos obtenidos de origen vegetal llevan asociada una cierta cantidad de emisiones de Gases de Efecto Invernadero (GEI), que se cuantifican a través de su huella de carbono. De los GEI, la agricultura es principalmente responsable de la emisión de óxido nitroso (N2O), que es el que presenta mayor poder de calentamiento global. La metodología del IPCC, aparte de sobreestimar con su valor por defecto las emisiones de N2O de nuestros agrosistemas, no tiene en cuenta el fin último de la agricultura que es satisfacer la demanda mundial de alimentos, fibras y combustibles. Por ello, en este artículo se propone evaluar las emisiones de N2O en base al rendimiento del cultivo. Posteriormente, se enumeran una serie de buenas prácticas agrícolas cuyo fin es aumentar la eficiencia del uso del N por parte del cultivo así como reducir las emisiones de N2O

Association between sleep-disordered breathing and breast cancer aggressiveness

Background Sleep-disordered breathing (SDB) has been associated with cancer aggressiveness, but studies focused on specific tumors are lacking. In this pilot study we investigated whether SDB is associated with breast cancer (BC) aggressiveness. Methods 83 consecutive women <65 years diagnosed with primary BC underwent a home respiratory polygraphy. Markers of SDB severity included the apnea-hypopnea index (AHI) and the 4% oxygen desaturation index (ODI4). The Ki67 proliferation index, lack of hormone receptors (HR-), Nottingham Histological Grade (NHG), and tumor stage were used as markers of BC aggressiveness. The association between SDB and molecular subtypes of BC was also assessed. Results The mean (SD) age was 48.8 (8.8) years and body mass index was 27.4 (5.4) Kg/m2. 42 women (50.6%) were post-menopausal. The median (IQR) AHI was 5.1 (2–9.4), and ODI4 was 1.5 (0.5–5.8). The median (IQR) AHI did not differ between the groups with Ki67>28% and Ki6728% and Ki67<29% (51.2% vs 52.3%, p = 0.90), HR- and HR+ (58.3% vs 49.1%, p = 0.47), NHG categories (p = 0.89), different tumor stages (p = 0.71), or molecular subtypes (p = 0.73). These results did not change when the ODI4 was used instead of the AHI. Conclusion Our results do not support an association between the presence or severity of SDB and BC aggressiveness.Asociación de Neumología y Cirugía Torácica del Sur (NEUMOSUR) 1/201

Designing bioactive porous titanium interfaces to balance mechanical properties and in vitro cells behavior towards increased osseointegration

Titanium implant failures are mainly related to stress shielding phenomenon and the poor cell interaction with host bone tissue. The development of bioactive and biomimetic Ti scaffolds for bone regeneration remains a challenge which needs the design of Ti implants with enhanced osseointegration. In this context, 4 types of titanium samples were fabricated using conventional powder metallurgy, fully dense, dense etched, porous Ti, and porous etched Ti. Porous samples were manufactured by space holder technique, using ammonium bicarbonate particles as spacer in three different ranges of particle size (100–200 μm, 250–355 μm and 355–500 μm). Substrates were chemically etched by immersion in fluorhydric acid at different times (125 and 625 s) and subsequently, were characterized from a micro-structural, topographical and mechanical point of view. Etched surfaces showed an additional roughness preferentially located inside pores. In vitro tests showed that all substrates were biocompatible (80% of cell viability), confirming cell adhesion of premioblastic cells. Similarly, osteoblast showed similar cell proliferation rates at 4 days, however, higher cell metabolic activity was observed in fully dense and dense etched surfaces at 7 days. In contrast, a significant increase of alkaline phosphatase enzyme expression was observed in porous and porous etched samples compared to control surfaces (dense and dense etched), noticing the suitable surface modification parameters (porosity and roughness) to improve cell differentiation. Furthermore, the presence of pores and rough surfaces of porous Ti substrates remarkably decreased macrophage activation reducing the M1 phenotype polarization as well M1 cell marker expression. Thus, a successful surface modification of porous Ti scaffolds has been performed towards a reduction on stress shielding phenomenon and enhancement of bone osseointegration, achieving a biomechanical and biofunctional equilibrium.Ministry of Economy and Competitiveness of Spain grant MAT2015-71284-PJunta de Andalucía – FEDER (Spain) Project Ref. P12-TEP-140

Pharmacological and Nonpharmacological Therapeutic Strategies Based on the Pathophysiology of Acute and Chronic Spinal Cord Injury

Spinal cord injury (SCI) induces a series of anatomic and physiological disorders which have severe repercussions on neural function. SCI is classified chronologically into an acute (primary and secondary phase) and a chronic phase. The primary phase results directly from the initial trauma and is comprised of disturbances in neural tissue (mainly axons), blood vessels, and spinal shock. Secondary injury results from a series of time-dependent pathophysiological changes, beginning in the first minutes after SCI and lasting days and weeks. This phase is characterized by biochemical and immunological alterations in the injury site and periphery, leading to neuronal over-excitation, apoptosis, and axonal demyelination. In chronic stages, the pathophysiology consists of disturbances in fiber organization, oligodendrocyte apoptosis, fibroglial scar formation, and cyst formation, leading to parenchymal alterations such as syringomyelia and hydromyelia hindering the possibility for functional basal axonal regeneration. This chapter will review a wide range of pharmacological and nonpharmacological therapeutic strategies in preclinical and clinical phases, each targeting different pathological mechanisms of SCI in acute and chronic stages of SCI; taking into account limitations, advances, scope, and new trends. The chapter focuses on the general aspects of SCI pathophysiology, pharmacological and nonpharmacological treatments acute and chronic stages of SCI

Fatigue behavior of polymer-modified porous concretes

Highly permeable materials provide drainage and noise absorption properties that are useful in pavement top-layers. In such porous concretes, the voids reduce the mechanical integrity, which may have to be compensated by the incorporation of non-conventional components, such as polymers. A basic property needed for the design of pavements is the fatigue behavior of the material, which has not been studied thoroughly for polymer modified porous concretes. The paper presents experimental results of fatigue tests in compression in terms of Wöhler curves for four porous concretes (two of them with polymer). It is seen that the polymer modified porous concretes exhibit better fatigue behavior than those without polymer. However, the improvement decreases for low values of the stress level, S, and appears to be negligible for the case of traffic loads in main roads or highways (number of load cycles, N >106). Additionally, the deformation and internal temperature evolutions have been monitored, and it is concluded that their trends are similar to those of conventional concrete, with temperature increases significantly higher than in conventional concretes.Peer Reviewe