Factors controlling the energetics of the oxygen reduction reaction on the Pd-Co electro-catalysts: Insight from first principles

We report here results of our density functional theory based computational studies of the electronic structure of the Pd-Co alloy electrocatalysts and energetics of the oxygen reduction reaction (ORR) on their surfaces. The calculations have been performed for the (111) surfaces of pure Pd, Pd0.75Co0.25 and Pd0.5Co0.5 alloys, as well as of the surface segregated Pd/Pd0.75Co0.25 alloy. We find the hybridization of dPd and dCo electronic states to be the main factor controlling the electrocatalytic properties of Pd/Pd0.75Co0.25. Namely the dPd - dCo hybridization causes low energy shift of the surface Pd d-band with respect to that for Pd(111). This shift weakens chemical bonds between the ORR intermediates and the Pd/Pd0.75Co0.25 surface, which is favorable for the reaction. Non-segregated Pd0.75Co0.25 and Pd0.5Co0.5 surfaces are found to be too reactive for ORR due to bonding of the intermediates to the surface Co atoms. Analysis of the ORR free energy diagrams, built for the Pd and Pd/Pd0.75Co0.25, shows that the co-adsorption of the ORR intermediates and water changes the ORR energetics significantly and makes ORR more favorable. We find the onset ORR potential estimated for the configurations with the O - OH and OH - OH co-adsorption to be in very good agreement with experiment. The relevance of this finding to the real reaction environment is discussed

Stability, Structure and Scale: Improvements in Multi-modal Vessel Extraction for SEEG Trajectory Planning

Purpose Brain vessels are among the most critical landmarks that need to be assessed for mitigating surgical risks in stereo-electroencephalography (SEEG) implantation. Intracranial haemorrhage is the most common complication associated with implantation, carrying signi cant associated morbidity. SEEG planning is done pre-operatively to identify avascular trajectories for the electrodes. In current practice, neurosurgeons have no assistance in the planning of electrode trajectories. There is great interest in developing computer assisted planning systems that can optimise the safety pro le of electrode trajectories, maximising the distance to critical structures. This paper presents a method that integrates the concepts of scale, neighbourhood structure and feature stability with the aim of improving robustness and accuracy of vessel extraction within a SEEG planning system. Methods The developed method accounts for scale and vicinity of a voxel by formulating the problem within a multi-scale tensor voting framework. Feature stability is achieved through a similarity measure that evaluates the multi-modal consistency in vesselness responses. The proposed measurement allows the combination of multiple images modalities into a single image that is used within the planning system to visualise critical vessels. Results Twelve paired datasets from two image modalities available within the planning system were used for evaluation. The mean Dice similarity coe cient was 0.89 ± 0.04, representing a statistically signi cantly improvement when compared to a semi-automated single human rater, single-modality segmentation protocol used in clinical practice (0.80 ±0.03). Conclusions Multi-modal vessel extraction is superior to semi-automated single-modality segmentation, indicating the possibility of safer SEEG planning, with reduced patient morbidity

La resistencia afrodescendiente en la Gobernación de Popayán

Este articulo plantea el interrogante que averigua por el papel cumplido por los afrodescendientes en el proceso de independencia, con su reconocida y permanente resistencia a la esclavitud. Para enfrentar este interrogante y entender la resistencia afrodescendiente, es necesario establecer: ¿Qué es aquello a lo que se resiste?, ¿Qué se busca con tal resistencia?Las respuestas obvias parecen ser: se resiste a la esclavitud y se busca la libertad. Pero, en este caso, a que esclavitud o aspectos de ella se resiste y, en su búsqueda, ¿a qué libertad se aspira? ¿Será, acaso, que se puede considerar la opresión sufrida por los habitantes criollos de América, bajo el régimen colonial, equiparable al sometimiento a la esclavitud de los afrodescendientes? Igualmente: ¿qué acepciones del término libertad, se aplica a cada caso?Palabras clave: Afrodescendientes, Esclavitud, cimarrones, Independencia, Resistencia. This article raises the question to find out the role played by their descendants in the process of independence, with its recognized and continued resistance to slavery. To address this question and understand the resistance of African descent, it is necessary: What is that to which you resist?, what is sought with such resistance?The answers seem obvious: to resist slavery and sought freedom. But in this case, to slavery or aspects of it resists and, in their search, what freedom is drawn? Is it, perhaps you can consider the oppression of the Creole inhabitants of America, under the colonial regime, comparable to the enslavement of African descent? Also, what meanings of the word freedom, is applied to each case?Keywords: African descendant, Slavery, Runaway, Independence, Resistanc

La resistencia afrodescendiente en la Gobernación de Popayán

Este articulo plantea el interrogante que averigua por el papel cumplido por los afrodescendientes en el proceso de independencia, con su reconocida y permanente resistencia a la esclavitud. Para enfrentar este interrogante y entender la resistencia afrodescendiente, es necesario establecer: ¿Qué es aquello a lo que se resiste?, ¿Qué se busca con tal resistencia?Las respuestas obvias parecen ser: se resiste a la esclavitud y se busca la libertad. Pero, en este caso, a que esclavitud o aspectos de ella se resiste y, en su búsqueda, ¿a qué libertad se aspira? ¿Será, acaso, que se puede considerar la opresión sufrida por los habitantes criollos de América, bajo el régimen colonial, equiparable al sometimiento a la esclavitud de los afrodescendientes? Igualmente: ¿qué acepciones del término libertad, se aplica a cada caso?Palabras clave: Afrodescendientes, Esclavitud, cimarrones, Independencia, Resistencia. This article raises the question to find out the role played by their descendants in the process of independence, with its recognized and continued resistance to slavery. To address this question and understand the resistance of African descent, it is necessary: What is that to which you resist?, what is sought with such resistance?The answers seem obvious: to resist slavery and sought freedom. But in this case, to slavery or aspects of it resists and, in their search, what freedom is drawn? Is it, perhaps you can consider the oppression of the Creole inhabitants of America, under the colonial regime, comparable to the enslavement of African descent? Also, what meanings of the word freedom, is applied to each case?Keywords: African descendant, Slavery, Runaway, Independence, Resistanc

DTA/TGA/DSC and densification data for iron phosphate glasses having natural UO2.67 or surrogate Bi2O3 added

A new set of iron-uranium phosphate glasses containing (1–20) UO2.67. (10–20) Fe2O3. (55–68) P2O5 (mass/%) were melted adequately. They were tested for glassy matrices to immobilize hazardous wastes such as radioactive ones. Likewise, new compositions had uranium oxide replaced with Bi2O3. Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and dilatometry measurements allowed us to study the thermal properties. TGA runs on phosphate glasses containing Fe and U oxides indicated that on heating the glasses, up to TS (dilatometric softening point), the Fe2+ ions oxidized irreversibly to Fe3+ ions which can increase the thermal stability of the glasses by delaying (or even avoiding) crystallization. The densification behavior, applied to pressed powder pellets of ground glasses, from controlled heating rate (CHR) runs (Δl/lo versus T/K), shows relative sample length change versus temperature during heating, provided further thermal data like densification details as well as definition of ranges of creep stability. Various DTA, DSC methods allowed estimating the activation energy for crystallization of these kind of glasses. In addition, separate crystallization treatments for a particular composition provided samples suitable to study the shape and content of crystals with the Scanning Electron Microscope (SEM)/Energy-Dispersive X-ray Spectroscopy (EDS) technique. Thus, a new family of iron-phosphate glasses having Na2O, Al2O3 added (RR6—RR62—RR63) is presented and discussed here and compared to various glasses (like PFeOx and PFeUOx) previously developed at the Bariloche Atomic Center, Argentina (CAB) for radioactive waste immobilization. Activation energies depicted roughly similar values for viscous flow densification of glasses melted with controlled amounts of UO2 for the earlier compositions as well as for the new formulations.Fil: Arboleda Zuluaga, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Rincón, Jesús Ma.. No especifíca;Fil: Gonzalez Oliver, Carlos Julian R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentin

Frecuencia de comportamientos anormales y estereotipados en caballos de patrullaje policial urbano : estudio de 48 horas continuas

ABSTRACT: Abnormal and stereotypic behaviors in horses have been widely studied around the world and different epidemiological situations have been described for behavioral disturbances. Objective: To determine the frequency of abnormal and stereotypic behaviors in a population of police patrolling horses. Additionally, to establish chronic stress levels in the population of interest. Methods: Twenty police horses were evaluated. The animals went through 48 hours of continuous observation to record the frequency of normal, abnormal, and stereotypic behaviors. Cortisol index (CI) was calculated for all the subjects. Results: A 65% of the horses expressed behavioral disturbances, with 55% corresponding to stereotypies. The abnormal behaviors consisted on wood chewing, pawing, and bed eating. Stereotypic behaviors were weaving, stall walking, and aerophagia (crib-biting or wind sucking). According to the CI, 13 horses were under chronic stress (CI<0.30). Conclusion: High level of chronic stress, expressed as abnormal and stereotypic behaviors, was observed in the horses.RESUMEN: los comportamientos anormales y estereotipados en caballos han sido ampliamente estudiados en el mundo, así como también diversas situaciones epidemiológicas relacionadas con estos disturbios. Objetivo: determinar la frecuencia de los comportamientos anormales y estereotipados en una población de caballos de patrullaje de la policía y establecer su nivel de estrés crónico. Métodos: se evaluaron 20 caballos. Los animales fueron observados durante 48 horas continuas para recopilar los comportamientos anormales y estereotipados. El índice del cortisol (CI) fue calculado para todos los animales. Resultados: el 65% de la población estudiada expresó disturbios del comportamiento, y el 55% de dichos disturbios se clasificó como estereotipias. Los comportamientos anormales observados consistieron en lignofagia, patear y comer cama. Los comportamientos estereotipados fueron balanceo, caminar en círculos y aerofagia. El CI mostró presencia de estrés crónico en 13 caballos (CI<0.30). Conclusión: se encontró un alto porcentaje de estrés crónico en los caballos de la policía, expresado como comportamientos anormales y estereotipados

Computational assembly of a human Cytomegalovirus vaccine upon experimental epitope legacy

Background: Human Cytomegalovirus (HCMV) is a ubiquitous herpesvirus affecting approximately 90% of the world population. HCMV causes disease in immunologically naive and immunosuppressed patients. The prevention, diagnosis and therapy of HCMV infection are thus crucial to public health. The availability of effective prophylactic and therapeutic treatments remain a significant challenge and no vaccine is currently available. Here, we sought to define an epitope-based vaccine against HCMV, eliciting B and T cell responses, from experimentally defined HCMV-specific epitopes. Results: We selected 398 and 790 experimentally validated HCMV-specific B and T cell epitopes, respectively, from available epitope resources and apply a knowledge-based approach in combination with immunoinformatic predictions to ensemble a universal vaccine against HCMV. The T cell component consists of 6 CD8 and 6 CD4 T cell epitopes that are conserved among HCMV strains. All CD8 T cell epitopes were reported to induce cytotoxic activity, are derived from early expressed genes and are predicted to provide population protection coverage over 97%. The CD4 T cell epitopes are derived from HCMV structural proteins and provide a population protection coverage over 92%. The B cell component consists of just 3 B cell epitopes from the ectodomain of glycoproteins L and H that are highly flexible and exposed to the solvent. Conclusions: We have defined a multiantigenic epitope vaccine ensemble against the HCMV that should elicit T and B cell responses in the entire population. Importantly, although we arrived to this epitope ensemble with the help of computational predictions, the actual epitopes are not predicted but are known to be immunogenic

Principales nemátodos fitoparasitos asociados con cultivos de plátano (Musa AAb y Musa ABB) en cuatro regiones de Colombia

Se realizó un reconocimiento general de nemátodos ecto y endoparásitos prevalentes en 4 zonas de producción de plátano. Los géneros de mayor diseminación fueron Helicotylenchus, Pratylenchus y Meloidogyne. De estos el que causa mayores daños es el nemátodo de la lesión radical, generalmente la especie P. coffeae, el cual en las zonas bananeras de la Costa Atlántica se encuentra en niveles altos de parasitismo. Los géneros Meloidogyne y Helicotylenchus fueron más prevalentes con altos niveles de población, en la región cafetera del Quindió donde posiblemente pueden causar pérdidas en producción de fruta. Radopholus similis se observó también en las regiones de la Costa, especialmente en la zona de Urabá, donde puede estar causando daños de importancia. Hoplolaimus seinhorsti fue identificado frecuentemente en la zona bananera de Santa Martha. R. similis no fue detectado en las 2 zonas del interior, sólo de material introducido al Quindió de la región de Urabá, lo cual implica un peligro potencial para ésta importante zona de producción del interior del paísEl plátano (Musa AÁAB y ARB) es considerado como uno de Jos alimentos basicós del pueblo colombiano, por lo: cuul: se cultiva en todas fas reglenes del pais desde las llanuras de lus costas, en arillos océanos, hasta os valles interandinos y las vertientes de las Cordilleras. donde generelmente se encuentra intercalado con útros. cultivos Importentes, como el cate, el cecao, la yuca y al malz. Es asi como para 1975, se colculuba, ul área de este quibvóo en superior a las 385,000 hectáreas con una produeción estimada de 1.300 000 toneladas métricas de frila (8). Sin embargo, debido a que tragficionalmente el cultivo del plátano ha sido: una actividad de producción para constimo interno. hasta la, presente no há existido una atención prioritaria para aplicar tecnologia con el lin de mejorar el cultivo e ¡dentificar los printipales probiemas fitosanitarioqsu:e lo efectán, Dentro de estos problemas pcupa especial importencia el relacionado. cen el parasitismo de nemétodos, a los cuales el plátano presenta un alto grado de susceptibilidad. El presente trabajo: tuvo: como objetivo principal etectuar un réconocimiento de. nernátodos en algubas de las principales zonas de producción de pláteno del a con el fin de conocer Ja Iiiportancia rejativa Uel problema y sugerir algunas medidas dé control para evitar la: dispersión de algunos grupos de nenátados firoparásitos. que puedan considerarse ¡como Ung arrenaza potencial para ciertes zones de producción de plátano.Plátano-Musa sapientu