802 research outputs found

    mHealth intervention development to support patients with active tuberculosis

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    Background: Mobile Health (mHealth) based interventions have been increasingly used to improve a broad range of health outcomes. However, few researchers have reported on the process or the application of theory to guide the development of mHealth based interventions, or specifically for tuberculosis (TB) treatment management. Aims: To describe the steps, process, and considerations in developing a text messaging-based intervention to promote treatment adherence and provide support to patients with active TB. Methods: Traditional qualitative techniques, including semi-structured interviews, field notes, content analysis, iterative coding, and thematic analysis, were used to design and document the intervention development with a multidisciplinary team of researchers, clinicians, administrators, and patients who were in active TB treatment. The Information-Motivation-Behavioral Skills (IMB) model was used to guide the coding scheme for content analysis of patient-directed TB educational material and intervention development. Results: The development steps included: a) establishing intervention components, including justifications, considerations, timing and frequency of components; b) developing educational messages, including cultural adaption, text or short message service (SMS) formatting, and prioritizing message delivery order; and c) determining implementation protocol. A set of 16 IMB-based messages were developed for the educational component. Final intervention development was achieved in 3 months. Conclusion: A collaborative approach and application of a theory to guide the intervention design and development is supported. Although a collaborative approach was more time consuming, it resulted in a more responsive, culturally appropriate, and comprehensive intervention. Considerations for developing a text messaging based intervention are provided and may serve as a guide for similar interventions. Further empirical evidence is needed for applying the IMB model for adherence-promotion in TB efforts

    Random Walks on Stochastic Temporal Networks

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    In the study of dynamical processes on networks, there has been intense focus on network structure -- i.e., the arrangement of edges and their associated weights -- but the effects of the temporal patterns of edges remains poorly understood. In this chapter, we develop a mathematical framework for random walks on temporal networks using an approach that provides a compromise between abstract but unrealistic models and data-driven but non-mathematical approaches. To do this, we introduce a stochastic model for temporal networks in which we summarize the temporal and structural organization of a system using a matrix of waiting-time distributions. We show that random walks on stochastic temporal networks can be described exactly by an integro-differential master equation and derive an analytical expression for its asymptotic steady state. We also discuss how our work might be useful to help build centrality measures for temporal networks.Comment: Chapter in Temporal Networks (Petter Holme and Jari Saramaki editors). Springer. Berlin, Heidelberg 2013. The book chapter contains minor corrections and modifications. This chapter is based on arXiv:1112.3324, which contains additional calculations and numerical simulation

    The evolution of Balmer jump selected galaxies in the ALHAMBRA survey

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    We present a new color-selection technique, based on the Bruzual & Charlot models convolved with the bands of the ALHAMBRA survey, and the redshifted position of the Balmer jump to select star-forming galaxies in the redshift range 0.5 < z < 1.5. These galaxies are dubbed Balmer jump Galaxies BJGs. We apply the iSEDfit Bayesian approach to fit each detailed SED and determine star-formation rate (SFR), stellar mass, age and absolute magnitudes. The mass of the haloes where these samples reside are found via a clustering analysis. Five volume-limited BJG sub-samples with different mean redshifts are found to reside in haloes of median masses 1012.5±0.2M\sim 10^{12.5 \pm 0.2} M_\odot slightly increasing toward z=0.5. This increment is similar to numerical simulations results which suggests that we are tracing the evolution of an evolving population of haloes as they grow to reach a mass of 1012.7±0.1M\sim 10^{12.7 \pm 0.1} M_\odot at z=0.5. The likely progenitors of our samples at z\sim3 are Lyman Break Galaxies, which at z\sim2 would evolve into star-forming BzK galaxies, and their descendants in the local Universe are elliptical galaxies.Hence, this allows us to follow the putative evolution of the SFR, stellar mass and age of these galaxies. From z\sim1.0 to z\sim0.5, the stellar mass of the volume limited BJG samples nearly does not change with redshift, suggesting that major mergers play a minor role on the evolution of these galaxies. The SFR evolution accounts for the small variations of stellar mass, suggesting that star formation and possible minor mergers are the main channels of mass assembly.Comment: 14 pages, 10 figures. Submitted to A&A. It includes first referee's comments. Abstract abridged due to arXiv requirement

    Electronic structure of crystalline binary and ternary Cd-Te-O compounds

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    The electronic structure of crystalline CdTe, CdO, α\alpha-TeO2_2, CdTeO3_3 and Cd3_3TeO6_6 is studied by means of first principles calculations. The band structure, total and partial density of states, and charge densities are presented. For α\alpha-TeO2_2 and CdTeO3_3, Density Functional Theory within the Local Density Approximation (LDA) correctly describes the insulating character of these compounds. In the first four compounds, LDA underestimates the optical bandgap by roughly 1 eV. Based on this trend, we predict an optical bandgap of 1.7 eV for Cd3_3TeO6_6. This material shows an isolated conduction band with a low effective mass, thus explaining its semiconducting character observed recently. In all these oxides, the top valence bands are formed mainly from the O 2p electrons. On the other hand, the binding energy of the Cd 4d band, relative to the valence band maximum, in the ternary compounds is smaller than in CdTe and CdO.Comment: 13 pages, 15 figures, 2 tables. Accepted in Phys Rev

    Young Galaxy Candidates in the Hubble Frontier Fields - III. MACSJ0717.5+3745

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    In this paper we present the results of our search for and study of z6z \gtrsim 6 galaxy candidates behind the third Frontier Fields (FF) cluster, MACSJ0717.5+3745, and its parallel field, combining data from Hubble and Spitzer. We select 39 candidates using the Lyman Break technique, for which the clear non-detection in optical make the extreme mid-zz interlopers hypothesis unlikely. We also take benefit from z6z \gtrsim 6 samples selected using previous Frontier Fields datasets of Abell 2744 and MACS0416 to improve the constraints on the properties of very high-redshift objects. We compute the redshift and the physical properties, such emission lines properties, star formation rate, reddening, and stellar mass for all Frontier Fields objects from their spectral energy distribution using templates including nebular emission lines. We study the relationship between several physical properties and confirm the trend already observed in previous surveys for evolution of star formation rate with galaxy mass, and between the size and the UV luminosity of our candidates. The analysis of the evolution of the UV Luminosity Function with redshift seems more compatible with an evolution of density. Moreover, no robust zz\ge8.5 object is selected behind the cluster field, and few zz\sim9 candidates have been selected in the two previous datasets from this legacy survey, suggesting a strong evolution in the number density of galaxies between zz\sim8 and 9. Thanks to the use of the lensing cluster, we study the evolution of the star formation rate density produced by galaxies with L>>0.03L^{\star}, and confirm the strong decrease observed between zz\sim8 and 9.Comment: 21 pages - Accepted for publication in ApJ - v2: small correction

    Unidad didáctica “Cambio climático y producción de energía” para la asignatura de Sistemas Ambientales y Sociedades del Programa del Diploma del Bachillerato Internacional

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    En el contexto del actual mundo globalizado, el cambio climático es entendido como un gran problema, en cuanto a magnitud y causas que lo generan, que abarcan lo personal, lo social y lo ambiental. Al ser un problema multifactorial, la lucha contra el cambio climático requiere de medidas globales que afecten a niveles políticos, estructurales, económicos y educativos, entre otros. En este trabajo el cambio climático se ha abordado desde las posibilidades que la educación puede proporcionar para ayudar a reducir las consecuencias derivadas de dicho fenómeno. Concretamente, se ha desarrollado una unidad didáctica que recoge tantos los valores que proporciona la Educación Ambiental (EA) como el perfil de la comunidad del Bachillerato Internacional (IB). Esta instrucción se ha enmarcada dentro de la asignatura de Sistemas Ambientales y Sociedades (SAS) del Programa del Diploma (PD). Esta unidad didáctica pretende ofrecer una educación individualizada y centrada en el alumno, para facilitar la máxima eficiencia posible en los aprendizajes del alumnado.In the context of today´s globalized world, climate change is understood as a big problem, in terms of magnitude and causes that generate it, covering the personal, the social and the environmental. Being a multifactorial problem, the fight against climate change requires global measures that affect political, structural economic and educational levels, among others. In this work climate change has been addressed from the possibilities that education can provide to reduce the consequences derived from said phenomenon. Specifically, a didactic unit has been developed that collects both the values provided by Environmental Education (EE) and the profile of the International Baccalaureate (IB) community. This instruction has been framed within the subject of Environmental Systems and Societies (ESS) of the Diploma Program (DP). This didactic unit aims to offer an individualized and student-centered education, to facilitate maximum possible efficiency in student learning

    The 2015 Chileno Valley glacial lake outburst flood, Patagonia

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    Glacial Lake Outburst Floods (GLOFs) have become increasingly common over the past century in response to climate change, posing risks for human activities in many mountain regions. In this paper we document and reconstruct the sequence of events and impact of a large GLOF that took place in December 2015 in the Chileno Valley, Patagonia. Hydrograph data suggests that the flood continued for around eight days with an estimated total discharge of 105.6 × 106 m3 of water. The sequence of events was as follows: (1) A large debris flow entered the lake from two steep and largely non-vegetated mountain gullies located northeast of the Chileno Glacier terminus. (2) Water displaced in the lake by the debris flow increased the discharge through the Chileno Lake outflow. (3) Lake and moraine sediments were eroded by the flood. (4) Eroded sediments were redistributed downstream by the GLOF. The post-GLOF channel at the lake outlet widened in some places by >130 m and the surface elevation of the terrain lowered by a maximum of 38.8 ± 1.5 m. Farther downstream, large amounts of entrained sediment were deposited at the head of an alluvial plain and these sediments produced an ~340 m wide fan with an average increase in surface elevation over the pre-GLOF surface of 4.6 ± 1.5 m. We estimate that around 3.5 million m3 of material was eroded from the flood-affected area whilst over 0.5 million m3 of material was deposited in the downstream GLOF fan. The large debris flow that triggered the GLOF was probably a paraglacial response to glacier recession from its Little Ice Age limits. We suggest that GLOFs will continue to occur in these settings in the future as glaciers further recede in response to global warming and produce potentially unstable lakes. Detailed studies of GLOF events are currently limited in Patagonia and the information presented here will therefore help to inform future glacial hazard assessments in this region
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