Polar intermetallic compounds of the silicon and arsenic family elements and their ternary hydrides and fluorides

An investigation has been made on the effects of hydrogen and fluoride in the solid state chemistry of alkaline-earth and divalent rare-earth metal pnictide (Pn) and tetrelide (Tt) phases A5(Pn,Tt,)3Zx, where A = Ca, Sr, Ba, Sm, Eu, Yb; Pn = As, Sb, Bi; Tt = Si, Ge, Sn, Pb and Z = H, F. Several trivalent rare-earth-metal pnictides, RE5Pn3 (RE = Y, La, Gd, Tb, Dy, Ho, Er, Tm) and alkaline-earth-metal trielides, A5Tr3Zx (Tr = Ga, In, Tl) have been included in an effort to complete observed structural trends. Two main experimental techniques were followed throughout this work, (a) reactions in absence of hydrogen or under continuous high vacuum, and (b) reactions with binary metal hydrides, AHx, in closed containers. Ternary fluorides followed to a large extent the chemistry of the corresponding ternary hydrides.;The results demonstrate that all the phases reported with the [beta]- Yb5Sb3-type structure in the A5Pn3 systems are hydrogen-stabilized compounds. Reactions in absence of hydrogen lead to compounds with the Mn5Si3-type structure. The structure type [beta]- Yb5Sb3 (=Ca5Sb3F) was found to be characteristic of ternary systems and inaccurately associated with phases that form in the Y5Bi3-type, a structure that is distinctive for pnictide compounds of trivalent metals. A new series of isomorphous Zintl compounds with the Ca16Sb11-type structure were prepared and studied as well.;All the alkaline-earth-metal tetrelides, A5Tt3, that crystallize in the Cr5B3-type structure can be interstitially derivatized by hydrogen or fluoride. Stannides and plumbides that form in this structure type are, with the exception of Sr5Sn3, hydrogen-stabilized compounds. Reactions in absence of hydrogen gave compounds in the Cr5B3, Ba5Si3, Pu31Pt20, Ca5Pb3 or W5Si3 structure types. Several new compounds with these structures were prepared. Additionally, an unprecedented Yb36Sn23 phase was discovered; its structure features isolated atoms, dimers and hexamers of tin.;Binary and ternary compounds were characterized by Guinier powder patterns, single crystal X-ray (30 structural refinements) and powder neutron (Ca5Bi3D and Ca5Sn3D samples) diffraction techniques. In an effort to establish property-structure relationships, electrical resistivity and magnetic measurements were performed on selected systems, and the results were explained in terms of the Zintl concepts, aided by extended Huckel band calculations. The structures of hydrogen-stabilized and electron deficient A5Tt3Hx compounds were rationalized in terms of multiple Tt-Tt bond interactions in these systems. ftn1This work was performed at the Ames Laboratory under contract no. W-7405-eng-82 with the U.S. Department of Energy. DOE Report no. IS-T 1730

Chambers of comerce: correspondence of its institutional function towards the impact and growth of the business sector

El presente estudio plantea la necesidad de analizar a las cámaras empresariales desde el enfoque de la teoría de las instituciones. El objetivo principal de esta investigación es determinar, como un primer intento, la correspondencia que existe entre el cumplimiento de la función institucional de las cámaras empresariales y el impacto que genera en el desarrollo del sector empresarial en el municipio de Querétaro con la actitud reflexiva de los empresarios. La presente investigación es un estudio exploratorio que utiliza una metodología de carácter cualitativo basado en la fenomenología. La muestra se definió de acuerdo con un muestreo no probabilístico de juicio secuencial, hasta determinar una saturación de categoría. Se utilizó como herramienta de recolección de información una guía de entrevista semiestructurada; el contacto que se obtuvo con los integrantes del sector empresarial fue con los propietarios de empresas micro y pequeñas de los sectores secundario y terciario con afiliación a alguna cámara empresarial.The present study raised from the need to analize the different chambers of commerce from the perspective of the institutional theory. The principal objective of this research is to determine, in a first attempt, the correspondence that exists between the compliance of the institutional function of the chambers of commerce and the impact generated on the growth in the business sector in the Queretaro municipality, through the reflection of the businessmen. The present investigation is classified as an exploratory study. For this condition it is precise to use a methology of qualitative character through phenomenology. To be able to define the effects the sample group it establishes the use of a not probabilistic model of sequencial judgement until a categorical saturation can be dertermined. A semistructural interview has been used as a recolection tool of information; members that have been contacted in business sector has been with the owners or general managers of micro and small businesses of the second and third sectors

Study of the mechanisms of immunomodulation used by Fasciola hepatica: Apoptosis and regulatory T cells

La fasciolosis causada por Fasciola hepatica es una enfermedad económicamente muy importante en rumiantes en climas templados. F. hepatica ha desarrollado una amplia variedad de mecanismos para munomodular o suprimir la respuesta inmune del hospedador haciéndola inefectiva, esto permite la supervivencia del parásito durante años. Esto constituye un serio obstáculo para la creación de vacunas protectoras en rumiantes. El conocimiento de los mecanismos de inmunomodulación llevados a cabo por F. hepatica para evadir la respuesta inmunitaria del hospdador es crucial para mejorar el diseño de vacunas. En infecciones por helmintos, los eosinófilos juegan un importante papel tanto en el desarrollo de la patología como en la defensa del hospedador. La apoptosis de estas células efectoras ha sido descrita como uno de los principales mecanismos de inmunosupresión o evasión durante las infecciones por helmintos. Existen trabajos que sugieren que los productos de excreción y secreción de F. hepatica inducen la apoptosis de los eosinófilos y de macrófagos peritoneales in vitro, así en los infiltrados inflamatorios en ratas in vivo. El empleo de anticuerpos anti-caspasa 3 es un método fácil, reproducible y sencillo para estudiar la presencia de apoptosis. El primer objetivo de este estudio, incluido en el Primer Trabajo fue demostrar la existencia de este fenómeno, como método de evasión de la respuesta inmunitaria del hospedador en ovejas infectadas con F. hepatica, in vivo.En el Segundo Trabajo el objetivo fue el estudio de la apoptosis de los leucocitos peritoneales en ovejas infectadas experimentalmente con F. hepatica durante la fase migratoria peritoneal en el hospedador. Fueron empleados cinco grupos, (n=5). El grupo 1 fue usado como control no infectado (control negativo), mientras que los grupos 2-5 fueron infectados oralmente con 200 mtc y sacrificados a los 1, 3, 9 y 18 dpi, respectivamente. El fenómeno de la apoptosis fue detectado mediante el empleo de tres métodos diferentes: 1) inmunocitoquímica empleando un anticuerpo policlonal anticaspasa- 3 activa; 2) ensayo de citometría de flujo usando Anexina V-FITC/ yoduro de propidio; y 3) microscopía electrónica de transmisión (TEM). El objetivo del Tercer Trabajo de la presente Tesis Doctoral fue evaluar la presencia y distribución de linfocitos T reguladores en el hígado y en los nódulos linfáticos en ovejas y cabras infectadas con F. hepatica durante las fases agudas y crónicas de la infección.Fasciolosis caused by Fasciola hepatica is an economically important disease of ruminants in temperate climates. F. hepatica has developed a variety of mechanisms to modulate or suppress the host response making it ineffective, which allows the parasite to survive in the host for years. The parasite host immune response modulation is a serious obstacle for developing protective vaccines for ruminants. The knowledge of the immunomodulation mechanisms carried out by F. hepatica to avoid the host immune response is a key to improve the vaccines development. In helminth infections, eosinophils play important roles both in developing tissue pathology and in the host effector response. Apoptosis of effector cells such as eosinophils and macrophages may play a role in the host immune evasion/suppression induced by helminth infection. Studies in the rat model have demonstrated that secreted excretory products of F. hepatica (FhESP) are able to induce apoptosis in eosinophils and peritoneal macrophages -in vitro- and in the inflammatory infiltrate - in vivo-, suggesting that apoptosis of effector cells may play a role in the host immune evasion/suppression induced by F. hepatica infection. The use of activated caspasa 3 antibodies is an easy, reliable and sensitive method to study the presence of apoptosis in tissue sections. The aim of this study, included in the First Work of this Thesis was to identify and quantify apoptosis of eosinophils in the hepatic inflammatory infiltrates of sheep challenged with F. hepatica during the migratory and biliary stages of infection. The aim of the Second Work was to evaluate the presence and number of inflammatory peritoneal leucocytes undergoing apoptosis in peritoneal fluid from sheep experimentally infected with F. hepatica during the peritoneal migratory stages in the host. Twenty five- merino sheep were used. They were divided into five groups (n=5): Group 1 was used as an uninfected control group (UC) and groups 2–5 were orally infected with one dose of 200 F. hepatica metacercariae and sheep from these groups were sacrificed by an intravenous injection of thiobarbital at 1, 3, 9, and 18 dpi, respectively. Apoptosis was detected using three different methods: 1) immunocytochemistry (ICC) with a polyclonal antibody anti-active caspase-3; 2) Flow cytometry assay using the Annexin V-FITC/propidium iodide (PI) kit; and 3) transmission electron microscopy (TEM). The aim of the Third Work of this Thesis was to evaluate the presence of Foxp3+ Tregs in liver and hepatic lymph nodes (HLN) from experimentally infected sheep and goats during acute and chronic stages of infection

Mejoramiento de Barrios en el Asentamiento 1 De Mayo, Desamparados, San José

ResumenEl presente trabajo consiste en una propuesta de mejoramiento de barrios informales, por medio de la aplicación de metodologías participativas en la comunidad de 1 de Mayo, ubicada en el cantón de Desamparados, de la provincia de San José. Aborda la problemática del hábitat degradado y el déficit de vivienda de este asentamiento. Sin embargo, se debe tomar en cuenta que es una de las principales problemáticas que afectan a la sociedad de hoy en día. Solo en América Latina, la producción social del hábitat es el principal gestor de ciudades. Esto se debe a que la oferta de vivienda existente en el mercado formal no da solución habitacional a las diferentes condiciones sociales y económicas de la población, generando concentraciones de pobreza y de riqueza que produce ciudades cada vez más desiguales. AbstractThis work is a proposal for the improvement of informal settlements, through the application of participatory methodologies in the community of 1 de Mayo, located in the canton of Desamparados, in the province of San José. The proposal addresses the problem of degraded habitat and housing deficit of the settlement. However, it should be noticed that these issues stand among the main problems affecting society today. Only in Latin America, the social production of the habitat is one of the central city management mechanisms. This condition takes place because the existing supply of housing in the formal housing market does not provide a solution for the different social and economic conditions of the population, generating concentrations of poverty and wealth which outcome is increasingly unequal city schemes.

Walkability index for the city of Bogotá

La movilidad peatonal es un aspecto recurrente en los discursos de la ciudad actual. Se espera que en las ciudades se generen espacios urbanos que fomenten la caminabilidad y, de esta manera, se promueva la reducción de la movilidad vehicular y la recuperación de la calidad ambiental, a fin de mejorar la calidad de vida de los ciudadanos. De esta manera, es necesario evaluar en términos cuantitativos las diferentes condiciones que permitan tener desplazamientos a pie, y con ello servir de base para la implementación de políticas de movilidad y espacio público que aporten a la generación de entornos más amigables. Para el caso de Bogotá se plantea la construcción y medición del índice de caminabilidad basado en cinco componentes: calidad ambiental, densidad, confort, proximidad y entropía aplicados en las Unidades de Planeamiento Zonal (UPZ), mediante el análisis de bases de datos espaciales y herramientas de sistemas de información geográfica (SIG). Se construye el índice entendiendo que es un indicador relativo de qué tan bien está el entorno construido en diferentes áreas para caminar, y qué condiciones de entorno propician dicho comportamiento. Se logra diagnosticar cuáles son los grados de caminabilidad por cada UPZ, y se distinguen diversas condiciones en los sectores analizados.A mobilidade de pedestres é um aspecto recorrente nos discursos da cidade atual. Espera-se que, nas cidades, sejam gerados espaços urbanos que fomentem a caminhabilidade e, dessa maneira, seja promovida a redução da mobilidade veicular e a recuperação da qualidade ambiental a fim de melhorar a qualidade de vida dos cidadãos. Assim, é necessário avaliar, em termos quantitativos, as diferentes condições que permitem ter deslocamentos a pé e, com isso, servir de base para implantar políticas de mobilidade e espaço público que contribuam para gerar ambientes mais amigáveis. Para o caso de Bogotá, Colômbia, são propostas a construção e a mediação do índice de caminhabilidade baseado em cinco componentes: qualidade ambiental, densidade, conforto, proximidade e entropia aplicados nas Unidades de Planejamento Zonal (UPZ), mediante a análise de bases de dados espaciais e ferramentas de sistemas de informação geográfica (SIG). Foi construído o índice entendendo que é um indicador relativo de quão bem está o ambiente construído em diferentes áreas para caminhar e quais condições de entorno propiciam esse comportamento. Pode-se diagnosticar quais são os graus de caminhabilidade por cada UPZ e foram diferenciadas as condições nos setores analisados.Pedestrian mobility has been a recurrent aspect in discourses on the contemporary city. It is expected that cities generate urban spaces that encourage walkability, promoting thus the reduction of vehicular mobility and the recovery of environmental quality, seeking to improve the quality of life of citizens. For this reason, it is necessary to quantitatively evaluate different conditions that allow citizens to have displacements on foot, and to use this as a basis for the implementation of mobility and public space policies that allow generating more pedestrian-friendly environments. In the case of Bogotá and its administrative divisions, the paper proposes the construction and measurement of a walkability index based on five components (environmental quality, density, comfort, proximity, and entropy) at the level of Zonal Planning Units (UPZ), through the analysis of spatial databases and Geographic Information System tools. This index is a relative indicator of how well the environment is constructed in different areas with respect to walking and what environmental conditions favor such behavior. It helps to diagnose the degree of walkability for each UPZ, as well as to distinguish diverse conditions in the analyzed areas

Why are the Trial-By-Trial, Strength-Based Criterion Shifts Hard to Observe? Is the Difficulty in the Mental Process Itself or in the Typical Cued-Criterion Method?

In the cued-criterion recognition paradigm (Stretch & Wixted, 1998a), trial-by-trial memory-strength based criterion shifts have been an elusive phenomenon. Often the criterion shifts fail to occur. We suggest that the frequent failure in making criterion shifts in the literature is due to participants’ failure to understand the rationale of the task as typically presented in an abstract format. In this study, participants studied words once or thrice and were asked at test to either classify the probes into “new”, “seen once”, or “seen 3 times” categories by pressing the corresponding keys, or to make an Old/New binary decision followed by an item presentation-frequency judgment, a confidence, or a memory-quality judgment. No memory-strength cues were provided and only one set of new items served as distractors for strong and weak targets. Robust trial-by-trial criterion shift was observed. We concluded that no cues distinguishing between strong and weak probes are necessary for obtaining this type of criterion shift when the tasks are designed to make good pragmatic sense for the participants. The reason why this type of criterion shifts is typically hard to obtain in the cued-criterion paradigm is not that the process itself is difficult, but that the cued-criterion method is hard to understand to the participants

Nuevas estrategias docentes en Histología. Más aprendizaje y menos enseñanza: Uso de microscopios virtuales e Historrelatos.

Current teaching at the University needs novel methodologies to increase students’ motivation. Here, we present two approaches to engage the student body to Human Histology subject at the University of Malaga. Virtual teaching was propelled by the COVID-19 crisis and confinement. The software for the study of histological/histopathological samples has become a valuable tool. Moreover, digital competences are in high demand within the biomedical field but students usually do not receive sufficient training. For these reasons, we have implemented the use of virtual microscopy (VM, Olympus), sharing 66 digitalized slides accessible under a username/password. VM provides real-time dynamic microscopy and offers an innovative experience at exceptionally high resolution. VM allows students to explore the samples online from anywhere, favoring autonomy and self-learning. Moreover, VM enables capturing specific tissue areas using these pictures to ask specific questions. On the other hand, transversal competences such as reading and writing skills, along with synthesis capability can be underdeveloped in our students. We initiated the activity of writing stories about histology contents (Histostories). Professional graphic designers from a webpage of scientific divulgation (masscience.com) illustrated the first story about erythrocytes. We conducted a survey among medical students to analyze the impact of this narration on their learning. Most of them welcome the initiative, considering it as an appropriate and enjoyable instrument for summarizing and revising the concepts. Immunity was among the topics more demanded between the students. Finally, we encouraged our students to write their own Histostories mentored by our teaching staff. These stories are shared through the virtual campus and on masscience website. So far, two medical students are collaborating with us in this experimental project that we expect it will bring more benefits to both readers and participants.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Greater capacity to exploit warming temperatures in northern populations of European beech is partly driven by delayed leaf senescence

One of the most widespread consequences of climate change is the disruption of trees’ phenological cycles. The extent to which tree phenology varies with local climate is largely genetically determined, and while a combination of temperature and photoperiodic cues are typically found to trigger bud burst (BB) in spring, it has proven harder to identify the main cues driving leaf senescence (LS) in autumn. We used 905 individual field observations of BB and LS from six Fagus sylvatica populations, covering the range of environmental conditions found across the species distribution, to: (i) estimate the dates of BB and LS of these populations; (ii) assess the main drivers of LS; and (iii) predict the likely variation in growing season length (GSL; defined as the period from BB to LS timing) across populations under current and future climate scenarios. To this end, we first calibrated linear mixed-effects models for LS as a function of temperature, insolation and BB date. Secondly, we calculated GSL for each population as the number of days between BB and LS. We found that: i) there were larger differences among populations in the date of BB than in the date of LS; ii) the temperature through September, October and November was the main determinant of LS, although covariation of temperature with daily insolation and precipitation-related variables suggests that all three variables may affect LS timing; and iii) GSL was predicted to increase in northern populations and to shrink in central and southern populations under climate change. Consequently, the large present-day differences in GSL across the range of beech are likely to decrease under future climates where rising temperatures will alter the relationship between BB and LS. Northern populations are likely to increase their productivity as warmer conditions will enable them to extend their growing season.Peer reviewe