Significant coercivity enhancement at low temperatures in magnetically oriented cobalt ferrite nanoparticles

The present work describes a synthesis and characterization strategy employed to study the magnetic anisotropic properties of a diluted nanoparticulate system. The system under analysis is composed of monodisperse and highly crystalline 16 nm Co0.5Fe2.5O4 nanoparticles (NPs), homogenously dispersed in 1-octadecene. Owing to the liquid nature of the matrix at room temperature, the relative orientation of the nanoparticle easy axis can be controlled by an external magnetic field, enabling us to measure how the magnetic properties are modified by the alignment of the particles within the sample. In turn, by employing this strategy, we have found a significant hardness and squareness enhancement of the hysteresis loop in the magnetically oriented system, with the coercive field reaching a value as high as 30.2 kOe at low temperatures. In addition, the magnetic behavior associated with the system under study was supported by additional magnetic measurements, which were ascribed to different events expected to take place throughout the sample characterization, such as the melting process of the 1-octadecene matrix or the NP relaxation under the Brownian mechanism at high temperatures.Fil: Tancredi, Pablo. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Rivas Rojas, Patricia Carolina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moscoso Londoño, Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Muraca, Diego. Universidade Estadual de Campinas; BrasilFil: Knobel, Marcelo. Universidade Estadual de Campinas; BrasilFil: Socolovsky, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; Argentin

Strategies to tailor the architecture of dual Ag/Fe-oxide nano-heterocrystals—interfacial and morphology effects on the magnetic behavior

Bifunctional nanostructured architectures have shown appealing properties, since a single entity can combine the diverse properties of its individual constituents. Particularly, by growing Fe-oxide domains over Ag nanoparticles, the plasmonic and superparamagnetic properties can be combined in a single particle. Beyond the multifunctionality of this system, there are several properties that emerge from intrinsic factors, such as: interface and/or morphology. In this study, we present the synthesis protocols to obtain two sets of heterocrystals, each one with different morphology: dimer and flower-like. In addition, the magnetization behavior of these hybrid nano-heterocrystals is investigated and discussed. These nanomaterials were built by a seed assisted heterogeneous nucleation process, carried out in organic solvents of high boiling point, using the same batch of silver nanoparticles with a mean size of 6 nm as seeds, and tuning the electron-donor capacity of the reaction environment at the thermal decomposition of the iron precursor. Ag/Fe3O4 heterocrystals with dimer and flower-like morphologies were obtained. The synthesis protocols for generating these types of nanomaterials are discussed step-by-step. Structural and morphological properties were determined by transmission electron microscopy, x-ray diffraction and x-ray absorption fine structure. DC magnetization results suggest that the silver/magnetite coupling generates an increase of the blocking temperature in comparison to those obtained from pure magnetite. This behavior could be linked to a possible increase in the magnetic anisotropy produced by an additional disorder at the Ag–Fe3O4 interface. The higher interface area of the Ag/Fe3O4 heterocrystals with flower-like architecture leads to a higher blocking temperature and a stronger magnetic anisotropy. These results are supported by AC susceptibility data.Fil: Tancredi Gentili, Pablo. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Laboratorio de Sólidos Amorfos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Moscoso Londoño, Oscar. Universidad Autónoma de Manizales; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidade Estadual de Campinas; BrasilFil: Rivas Rojas, Patricia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Laboratorio de Sólidos Amorfos; ArgentinaFil: Wolff, U.. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Socolovsky, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Knobel, M.. Universidade Estadual de Campinas; BrasilFil: Muraca, D.. Universidade Estadual de Campinas; Brasi

Natural landscape, infrastructure, and health : The physical activity implications of urban green space composition among the elderly

Unidad de excelencia María de Maeztu MdM-2015-0552This project was funded by the RecerCaixa research fund in the 2016 call, under the original title of Ciudad, calidad de vida y movilidad activa en la tercera edad: Un análisis multimetodológico a través de Tracking Living Labs.Urban green spaces (UGS) have been linked with a series of benefits for the environment, and for the physical health and well-being of urban residents. This is of great importance in the context of the aging of modern societies. However, UGS have different forms and characteristics that can determine their utilization. Common elements in UGS such as the type of vegetation and the type of surface are surprisingly understudied in regard to their relationship with the type of activity undertaken in UGS. This paper aims to explore the relationship between landscape diversity and the type of surface with the time spent and the physical activity intensity performed by seniors. To do so, this study uses GPS tracking data in combination with accelerometer data gathered from 63 seniors residing in Barcelona, Spain. Results showed that senior participants spent little time inside the analyzed UGS and sedentary behaviors (SBs) were more common than physical activities (PAs). The presence of pavement surfaces positively influenced the total time spent in UGS while gravel surfaces were negatively associated with time spent in active behaviors. The provision of well-defined and maintained paved areas and paths are some key infrastructures to be considered when designing UGS for overall urban residents and, especially, when aiming to potentiate the access for senior visitors

Environmental heterogeneity in human health studies. A compositional methodology for Land Use and Land cover data

Altres ajuts: Acord transformatiu CRUE-CSICUnidad de excelencia María de Maeztu CEX2019-000940-MThe use of Land use and Land cover (LULC) data is gradually becoming more widely spread in studies relating the environment to human health. However, little research has acknowledged the compositional nature of these data. The goal of the present study is to explore, for the first time, the independent effect of eight LULC categories (agricultural land, bare land, coniferous forest, broad-leaved forest, sclerophyll forest, grassland and shrubs, urban areas, and waterbodies) on three selected common health conditions: type 2 diabetes mellitus (T2DM), asthma and anxiety, using a compositional methodological approach and leveraging observational health data of Catalonia (Spain) at area level. We fixed the risk exposure scenario using three covariates (socioeconomic status, age group, and sex). Then, we assessed the independent effect of the eight LULC categories on each health condition. Our results show that each LULC category has a distinctive effect on the three health conditions and that the three covariates clearly modify this effect. This compositional approach has yielded plausible results supported by the existing literature, highlighting the relevance of environmental heterogeneity in health studies. In this sense, we argue that different types of environment possess exclusive biotic and abiotic elements affecting distinctively on human health. We believe our contribution might help researchers approach the environment in a more multidimensional manner integrating environmental heterogeneity in the analysis

Thermography as a method of acquiring competences in Physiology. Application case for hand blood flow control

5 p.The present work proposes a methodological structure as part of the learning of the circulatory system. For this, the application of thermal stress is used, by immersing the hands in cold water to visualize the reperfusion of the hands. Learning, based on the visualization and analysis of thermographic images, allows the acquisition of specific competences at the university level. In graduate studies such as physiotherapy and nursing, the use of virtual tools and materials that allow the acquisition of skills and technical knowledge is essential for the job performance of future professionals. The application of this methodology is proposed in practical sessions of subjects in the area of knowledge of Physiology, to demonstrate and facilitate the understanding of the circulatory system. This approach is framed within the discipline of virtual laboratories since the virtual materials generated can be used for the acquisition of skills and practical competencies, as well as for the evaluation of competencies in e-learning courses. In this way, by recording a pedagogical video that shows a short practice, 5 minutes long, it is possible to establish the necessary knowledge bases to expand them later. This material is easily implementable in any learning management system.S

Análisis de Costes y de Coste/Eficacia de las Pautas Recomendadas por GESIDA/Plan Nacional sobre el Sida en 2018 Para el Tratamiento Antirretroviral Inicial en Adultos Infectados Por el VIH

[Background]: The GESIDA/National AIDS Plan expert panel recommended preferred regimens (PR), alternative regimens (AR) and other regimens (OR) for antiretroviral treatment (ART) as initial therapy in HIV-infected patients for 2018. The objective of this study was to evaluate the costs and the efficiency of initiating treatment with PR and AR. [Methods]: Economic assessment of costs and efficiency (cost-effectiveness) based on decision tree analyses. Effectiveness was defined as the probability of reporting a viral load <50 copies/mL at week 48, in an intention-to-treat analysis. Cost of initiating treatment with an ART regimen was defined as the costs of ART and its consequences (adverse effects, changes of ART regimen, and drug-resistance studies) over the first 48 weeks. The payer perspective (National Health System) was applied considering only differential direct costs: ART (official prices), management of adverse effects, studies of resistance, and HLA B*5701 testing. The setting was Spain and the costs correspond to those of 2018. A deterministic sensitivity analysis was conducted, building three scenarios for each regimen: base case, most favourable and least favourable. [Results]: In the base-case scenario, the cost of initiating treatment ranges from 6788 euros for TAF/FTC/RPV (AR) to 10,649 euros for TAF/FTC + RAL (PR). The effectiveness varies from 0.82 for TAF/FTC + DRV/r (AR) to 0.91 for TAF/FTC + DTG (PR). The efficiency, in terms of cost-effectiveness, ranges from 7814 to 12,412 euros per responder at 48 weeks, for ABC/3TC/DTG (PR) and TAF/FTC + RAL (PR), respectively. [Conclusion]: Considering ART official prices, the most efficient regimen was ABC/3TC/DTG (PR), followed by TAF/FTC/RPV (AR) and TAF/FTC/EVG/COBI (AR).[Introducción]: El panel de expertos de GESIDA/Plan Nacional del Sida ha recomendado pautas preferentes (PP), pautas alternativas (PA) y otras pautas (OP) para el tratamiento antirretroviral (TAR) como terapia de inicio en pacientes infectados por VIH para 2018. El objetivo de este estudio es evaluar los costes y la eficiencia de iniciar tratamiento con PP y PA. [Métodos]: Evaluación económica de costes y eficiencia (coste/eficacia) mediante construcción de árboles de decisión. Se definió eficacia como la probabilidad de tener carga viral <50 copias/ml en la semana 48 en análisis por intención de tratar. Se definió coste de iniciar tratamiento con una pauta como los costes del TAR y de todas sus consecuencias (efectos adversos, cambios de pauta y estudio de resistencias) que se producen en las siguientes 48 semanas. Se utilizó la perspectiva del Sistema Nacional de Salud, considerando solo costes directos diferenciales: TAR (a precio oficial), manejo de efectos adversos, estudios de resistencias y determinación de HLA-B*5701. El ámbito es España, con costes de 2018. Se realizó un análisis de sensibilidad determinista construyendo 3 escenarios para cada pauta: basal, más favorable y más desfavorable. [Resultados]: En el escenario basal, los costes de iniciar tratamiento oscilaron entre 6.788 para TAF/FTC/RPV (PA) y 10.649 para TAF/FTC + RAL (PP). La eficacia osciló entre 0,82 para TAF/FTC + DRV/r (PA) y 0,91 para TAF/FTC + DTG (PP). La eficiencia, en términos de coste/eficacia, osciló entre 7.814 y 12.412 por respondedor a las 48 semanas, para ABC/3TC/DTG (PP) y TAF/FTC + RAL (PP), respectivamente. [Conclusión]: Considerando el precio oficial del TAR, la pauta más eficiente fue ABC/3TC/DTG (PP), seguida de TAF/FTC/RPV (PA) y TAF/FTC/EVG/COBI (PA)

EXD2 governs germ stem cell homeostasis and lifespan by promoting mitoribosome integrity and translation

Mitochondria are subcellular organelles critical for meeting the bioenergetic and biosynthetic needs of the cell. Mitochondrial function relies on genes and RNA species encoded both in the nucleus and mitochondria, as well as their coordinated translation, import and respiratory complex assembly. Here we describe the characterization of exonuclease domain like 2 (EXD2), a nuclear encoded gene that we show is targeted to the mitochondria and prevents the aberrant association of mRNAs with the mitochondrial ribosome. The loss of EXD2 resulted in defective mitochondrial translation, impaired respiration, reduced ATP production, increased reactive oxygen species and widespread metabolic abnormalities. Depletion of EXD2/CG6744 in D.melanogaster caused developmental delays and premature female germline stem cell attrition, reduced fecundity and a dramatic extension of lifespan that could be reversed with an anti-oxidant diet. Our results define a conserved role for EXD2 in mitochondrial translation that influences development and aging

Urban Green Space and Human Health: the Role of Quality Characteristics

La creixent urbanització està portant a un augment del número global de persones vivint en nuclis urbans. Simultàniament, l’evidència epidemiològica creix en referència als efectes beneficiosos dels espais verds urbans sobre la salut física i mental. Tot i això, fins ara, la majoria d’estudis epidemiològics sobre els efectes de la exposició a espais verds urbans s’han centrat en la presència (o absència) de verd urbà, passant per alt la seva qualitat. Tanmateix, la literatura apunta cap a la qualitat com a una font de possible incongruència en els resultats dels estudis on s’associa espais verds amb salut humana. Aquesta tesi té com a objectiu avaluar el rol de la qualitat dels espais verds i l’ús de diverses mesures d’aquests en la relació entre espais verds i salut humana. Primer, es posiciona la recerca mitjançant una revisió sistemàtica de les eines actualment disponibles per avaluar la qualitat dels espais verds urbans. Segon, es desenvolupa i implementa RECITAL, una nova eina per avaluar la qualitat dels espais verds urbans. Seguidament, les mesures generades per RECITAL a Barcelona (ES) són utilitzades per analitzar els efectes de la qualitat dels espais verds sobre el seu ús, l’activitat física i el sobrepès/obesitat. Finalment, s’analitzen les associacions de diverses mesures d’espai verd amb factors de risc cardiovascular en un estudi a Philadelphia (EE.UU.). Els resultats d’aquesta tesi suggereixen que tant la qualitat dels espais verds com l’ús de diferents mesures d’espai verd urbà juguen una funció essencial en l’associació entre espais de verd urbà i salut humana. A més, aquesta relació es veu modificada per factors socials, demogràfics, i econòmics.La creciente urbanización está llevando a un aumento del número global de personas viviendo en núcleos urbanos. Simultáneamente, la evidencia epidemiológica crece en referencia a los efectos beneficiosos de los espacios verdes urbanos sobre la salud física y mental. Aun así, hasta ahora, la mayoría de estudios epidemiológicos sobre los efectos de la exposición a espacios verdes urbanos se han centrado en la presencia (o ausencia) de verde urbano, pasando por alto su calidad. Sin embargo, la literatura apunta hacia la calidad como una fuente de posible incongruencia en los resultados de los estudios donde se asocia espacios verdes con salud humana. Esta tesis tiene como objetivo evaluar el rol de la calidad de los espacios verdes y el uso de varias medidas de estos en la relación entre espacios verdes y salud humana. Primero, se posiciona la investigación mediante una revisión sistemática de las herramientas actualmente disponibles para evaluar la calidad de los espacios verdes urbanos. Segundo, se desarrolla e implementa RECITAL, una nueva herramienta para evaluar la calidad de los espacios verdes urbanos. Seguidamente, las medidas generadas por RECITAL en Barcelona (ES) son utilizadas para analizar los efectos de la calidad de los espacios verdes sobre su uso, la actividad física y el sobrepeso/obesidad. Finalmente, se analizan las asociaciones de varias medidas de espacio verde con factores de riesgo cardiovascular en un estudio en Philadelphia (EE. UU.). Los resultados de esta tesis sugieren que tanto la calidad de los espacios verdes como el uso de diferentes medidas de espacio verde urbano juegan una función esencial en la asociación entre espacios de verde urbano y salud humana. Además, esta relación se ve modificada por factores sociales, demográficos, y económicos.The ongoing urbanization is leading to an increasing number of people living in urban areas worldwide. Concurrently, epidemiological evidence accumulates regarding the beneficial effects of green space on urban residents' physical and mental health. To date, most of the epidemiological studies of urban greenspaces exposure effects have only focused on the presence (or lack) of urban green, overlooking its quality. However, when looking for a source of inconsistency amongst the findings of the studies of the health benefits of green space exposure, the available literature points towards quality. This thesis aims to evaluate how the association between urban green spaces and human health is impacted by green space quality and the use of different greenspace measures. First, the stage is settled by systematically reviewing the currently available tools to assess the quality of urban green space. Second, the development and implementation of RECITAL, a novel quality assessment tool, is explained. Next, the quality assessment from RECITAL in Barcelona (ES) is used to analyze the role of quality in the association between urban green space and green space use, physical activity, and overweight/obesity. Finally, the associations of different greenspace exposure metrics with cardiovascular risk factors are evaluated and compared in a study based in Philadelphia (US). The results of this thesis suggest that both green space quality and the use of different greenspace measures play an essential role in the association between urban green spaces and human health. Moreover, this relationship is modified by the social, demographic, and economic personal context.Universitat Autònoma de Barcelona. Programa de Doctorat en Ciència i Tecnologia Ambiental

Supply-side economics: la economía argentina en 1983

Esta tesis solo está en formato papel por lo que se debe consultar en la propia Biblioteca Di Tella. La consulta se hace solo bajo reserva escribiendo a [email protected] tesis no tiene permisos por parte del autor para ser reproducida, por lo que no se puede fotocopiar, ni fotografiar ni reproducir con ningún medio. Si eres el autor de la tesis y quieres dar tu autorización para la reproducción, puedes ponerte en contacto con [email protected]

Development of the urban green space quality assessment tool (RECITAL)

The quality of green spaces could play a crucial role in green spaces’ health benefits and their underlying mechanisms. We developed and implemented the RECITAL: a multidimensional in situ quality assessment tool for urban green spaces, primarily to characterize quality aspects relevant to human health. The tool includes 90 items divided into eleven thematic dimensions. Applying RECITAL, we assessed the quality of 149 urban green spaces in Barcelona, Spain, and the obtained results showed overall good-to-excellent reliability. Decision-makers could use the quality scores generated by RECITAL to fine-tune the design and management of urban green spaces. Simultaneously, researchers could apply it to study how different quality aspects of urban green spaces would affect their potential to exert health benefits