710 research outputs found

    Epidemiology and Management of Hypertension in the Hispanic Population

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    Hispanics are the fastest growing ethnic minority in the USA. Among Hispanics, lack of hypertension awareness and lack of effective blood pressure (BP) control are problematic, as are higher incidence rates of hypertension-related co-morbidities compared with non-Hispanic populations. Moreover, there are currently no hypertension treatment guidelines that address the unique characteristics of this ethnic group. This article discusses ethnic differences in hypertension and cardiovascular risk factors and reviews the literature on the efficacy of antihypertensive agents in Hispanic patients, with a focus on the role of renin-angiotensinaldosterone system (RAAS) inhibition in the management of hypertension in these patients. Hypertension in Hispanic patients can be challenging to manage, in part because this population has a higher prevalence of obesity, diabetes, and metabolic syndrome compared with non-Hispanic whites. The presence of these comorbidities suggests that RAAS-inhibitor-based therapies may be particularly beneficial in this population. However, few studies have evaluated the efficacy of antihypertensive treatments in Hispanic patients. Two outcomes studies in hypertensive patients have shown the benefits of treating Hispanic patients with antihypertensive therapy and included RAAS inhibitors as part of the treatment regimen. In addition, BP-lowering trials have shown the antihypertensive efficacy of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and direct renin inhibitors, although data on the latter are more limited. Additional studies are needed to more thoroughly evaluate the effects of RAAS inhibitors (and other drug classes) on outcomes and BP lowering in the Hispanic hypertensive population

    The dynamics of copper intercalated molybdenum ditelluride

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    Layered transition metal dichalcogenides are emerging as key materials in nanoelectronics and energy applications. Predictive models to understand their growth, thermomechanical properties and interactions with metals are needed in order to accelerate their incorporation into commercial products. Interatomic potentials enable large-scale atomistic simulations at the device level, beyond the range of applications of first principle methods. We present a ReaxFF reactive force field to describe molybdenum ditelluride and its interactions with copper. We optimized the force field parameters to describe the properties of layered MoTe2 in various phases, the intercalation of Cu atoms and clusters within its van der Waals gap, including a proper description of energetics, charges and mechanical properties. The training set consists of an extensive set of first principle calculations computed from density functional theory. We use the force field to study the adhesion of a single layer MoTe2 on a Cu(111) surface and the results are in good agreement with density functional theory, even though such structures were not part of the training set. We characterized the mobility of the Cu ions intercalated into MoTe2 under the presence of an external electric fields via molecular dynamics simulations. The results show a significant increase in drift velocity for electric fields of approximately 0.4 V/A and that mobility increases with Cu ion concentration.Comment: 21 pages, 9 Figure

    The Fundamental Properties of Dwarf Elliptical Galaxies in Clusters

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    We present preliminary results of an extensive study of the fundamental properties of dwarf elliptical galaxies (dEs) in the Coma cluster. Our study will combine HST surface photometry with ground-based UBRIJK photometry and optical spectroscopy. The combined data set will be used to investigate the intrinsic correlations among global parameters in cluster dEs, including the Fundamental Plane, the color-magnitude relation, the Faber-Jackson and Kormendy relation, and velocity dispersion versus line strength indices. These empirical correlations have provided important constraints to theoretical models of galaxy formation and evolution for "normal" elliptical galaxies. Although dEs are the most abundant galaxy population in clusters their properties remain, however, largely unknown. Our study aims to provide an essential reference for testing current theories on the formation and evolution of dEs in clusters, and understanding their relation to more massive elliptical galaxies.Comment: 10 pages. To appear in "Star Formation through Time", 2003, ASP Conf. Ser. ed. Perez, Gonzalez Delgado, Tenorio-Tagl

    Understanding the Role of Power during the Implementation of BRT Systems

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    This research is about power. It is completely immersed in modern societies, reflections on power have not settled its definition. Regardless of centuries of considerations about power, there is still much to learn about its exercise. For decades, power has been analysed by scholars all over the world; however, transport planners have avoided issues concerning power. This dissertation focuses on the use of power during planning and implementation processes of two Bus Rapid Transit Systems; one in Quito, Ecuador, and another in Cambridge, England. Using a multimethod phronetic approach, this research examines how decisions were made for the implementation of BRT in the selected case studies. Phronetic methodology aims to explain social phenomena by piecing together large and small details that shape the context of events; in this case, existing planning documentation and the narratives of key stakeholders and decision-makers —such as former Mayors, Council Members, and Heads of Transport Departments— were used to understand the reasons behind the adoption of bus systems. Despite the contextual differences of geography, population, and political and administrative terms between Quito and Cambridge, there are key themes found in both case studies. Solving congestion and improving economic growth is a key motivation for the implementation of the systems in both cases. A complex network of actors is formed during the planning processes of BRT systems that shape the way decisions are made. In both cases, an isolated group of actors that lack the opportunity to exercise power was also identified. A sophisticated mixture of power mechanisms were discovered, which contained actors that had more experience, training and opportunities to exercise power. The findings of the analysis of power in Quito and Cambridge suggest that stakeholders with opportunities to exercise power —from the beginning— are also actors with more opportunities to influence the final uptake of the systems. Planners interested in participatory processes need to focus efforts to involve different communities as early as possible in the planning processes. The inclusion of communities does not guarantee that their needs and objectives will be incorporated into the planning process. A set of power mechanisms need to be developed by all members involved in the process. An early participation of these communities can help focus planning on solving people’s needs rather than the implementation of a specific scheme

    Isocuanta de la producción de leche semi intensiva en una región del Estado de México

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    Artículo arbitrado en revista CONACYTPara determinar niveles óptimo técnico (not) y óptimo económico (noe) del alimento concentrado y forraje en producción de leche, se construyó un modelo econométrico polinomial. La información provino de un rancho lechero, ubicado en Temascaltepec, Estado de México, durante agosto-septiembre 2013, dividido en cinco periodos de 15 días cada uno. El rancho dispuso 65 vacas pardo suizo, sólo se utilizaron 10 (pv 628 ± 72 kilogramos) con diferente número de partos y tiempo de lactación. Para concentrado y forraje, el not y noe, fueron 104.4 y 148.4; 78.5 y 109 kg; el productor utilizó 97.2 y 169 kg de esos insumos, con ganancia de $792.9. El noe es recomendación técnico-económica que los productores deben adoptar para maximizar su ganancia monetaria

    Velocity Dispersions and Stellar Populations of the Most Compact and Msssive early-Type Galaxies at Redshift similar to 1

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    We present Gran-Telescopio-Canarias/OSIRIS optical spectra of four of the most compact and massive early-type galaxies (ETGs) in the Groth Strip Survey at redshift z similar to 1, with effective radii R-e = 0.5-2.4 kpc and photometric stellarmasses M-star = (1.2-4) x 10(11)M(circle dot). We find that these galaxies have velocity dispersions sigma = 156-236 km s(-1). The spectra are well fitted by single stellar population models with approximately 1 Gyr of age and solar metallicity. We find that (1) the dynamical masses of these galaxies are systematically smaller by a factor of similar to 6 than the published stellarmasses using BRIJK photometry, and (2) when estimating stellarmasses as 0.7xM(dyn), a combination of passive luminosity fading with mass/size growth due to minor mergers can plausibly evolve our objects to match the properties of the local population of ETGs

    Soil biogeochemistry across Central and South American tropical dry forests

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    The availability of nitrogen (N) and phosphorus (P) controls the flow of carbon (C) among plants, soils, and the atmosphere, thereby shaping terrestrial ecosystem responses to global change. Soil C, N, and P cycles are linked by drivers operating at multiple spatial and temporal scales: landscape-level variation in macroclimate and soil geochemistry, stand-scale heterogeneity in forest composition, and microbial community dynamics at the soil pore scale. Yet in many biomes, we do not know at which scales most of the biogeochemical variation emerges, nor which processes drive cross-scale feedbacks. Here, we examined the drivers and spatial/temporal scales of variation in soil biogeochemistry across four tropical dry forests spanning steep environmental gradients. To do so, we quantified soil C, N, and P pools, extracellular enzyme activities, and microbial community structure across wet and dry seasons in 16 plots located in Colombia, Costa Rica, Mexico, and Puerto Rico. Soil biogeochemistry exhibited marked heterogeneity across the 16 plots, with total organic C, N, and P pools varying fourfold, and inorganic nutrient pools by an order of magnitude. Most soil characteristics changed more across space (i.e., among sites and plots) than over time (between dry and wet season samplings). We observed stoichiometric decoupling among C, N, and P cycles, which may reflect their divergent biogeochemical drivers. Organic C and N pool sizes were positively correlated with the relative abundance of ectomycorrhizal trees and legumes. By contrast, the distribution of soil P pools was driven by soil geochemistry, with larger inorganic P pools in soils with P-rich parent material. Most earth system models assume that soils within a texture class operate similarly, and ignore subgrid cell variation in soil properties. Here we reveal that soil nutrient pools and fluxes exhibit as much variation among four Neotropical dry forests as is observed across terrestrial ecosystems at the global scale. Soil biogeochemical patterns are driven not only by regional differences in soil parent material and climate, but also by local-scale variation in plant and microbial communities. Thus, the biogeochemical patterns we observed across the Neotropical dry forest biome challenge representation of soil processes in ecosystem models

    Generation of Human Antigen-Specific Monoclonal IgM Antibodies Using Vaccinated “Human Immune System” Mice

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    Passive transfer of antibodies not only provides immediate short-term protection against disease, but also can be exploited as a therapeutic tool. However, the 'humanization' of murine monoclonal antibodies (mAbs) is a time-consuming and expensive process that has the inherent drawback of potentially altering antigenic specificity and/or affinity. The immortalization of human B cells represents an alternative for obtaining human mAbs, but relies on the availability of biological samples from vaccinated individuals or convalescent patients. In this work we describe a novel approach to generate fully human mAbs by combining a humanized mouse model with a new B cell immortalization technique. After transplantation with CD34+CD38⁻ human hematopoietic progenitor cells, BALB/c Rag2⁻/⁻IL-2Rγc⁻/⁻ mice acquire a human immune system and harbor B cells with a diverse IgM repertoire. "Human Immune System" mice were then immunized with two commercial vaccine antigens, tetanus toxoid and hepatitis B surface antigen. Sorted human CD19+CD27+ B cells were retrovirally transduced with the human B cell lymphoma (BCL)-6 and BCL-XL genes, and subsequently cultured in the presence of CD40-ligand and IL-21. This procedure allows generating stable B cell receptor-positive B cells that secrete immunoglobulins. We recovered stable B cell clones that produced IgM specific for tetanus toxoid and the hepatitis B surface antigen, respectively. This work provides the proof-of-concept for the usefulness of this novel method based on the immunization of humanized mice for the rapid generation of human mAbs against a wide range of antigen
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