Incidencias de las decisiones de la administración en la economía y ejecución de un proyecto vial.

Proyecto de Graduación (Licenciatura en Ingeniería en Construcción) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería en Construcción, 2002.El estudio propone el diseño de un sistema para el reconocimiento de sobre costos en proyectos, todo enmarcado en la jurisprudencia de la Contratación Administrativa para proyectos de infraestructura vial desarrollados por el Ministerio de Obras Públicas y Transportes y el Consejo Nacional de Vialidad de la República de Costa Rica. Se evaluará la incidencia de factores ajenos al contratista; en el mantenimiento de la ecuación financiera de acuerdo a: - Inicio de obra tardía. - Suspensiones de obra. - Aumento de costos en los rubros del contrato. - Falta de reconocimiento de exoneraciones. Los proyectos a evaluados son: Barú-Piñuela-Palmar Norte, Fase C, Sección 1, Mantenimiento Periódico de la Zona de Cartago. El análisis se fundamenta en las leyes N° 5501, N° 5518, la Ley de Contratación Administrativa y su Reglamento, la jurisprudencia que al respecto han remitido la Sala Constitucional y la Contraloría General de la República. Los resultados son aplicables a otros contratos con el Estado en los que el tiempo de ejecución es considerable. Se agrupan la gama de posibilidades dentro del marco de estudio: Obras de infraestructura vial. Es importante recordar que los incrementos de los montos de los contratos son considerables y debe de prestárseles la importancia del caso, ya que las decisiones tomadas pueden desbalancear considerablemente el presupuesto de la obra

Planetesimal Compositions in Exoplanet Systems

We have used recent surveys of the composition of exoplanet host stars to investigate the expected composition of condensed material in planetesimals formed beyond the snow line in the circumstellar nebulae of these systems. Of the major solid forming elements, we find that, as for the Sun, the C and O abundances (and particularly the C/O abundance ratio) have the most significant effect on the composition of icy planetesimals formed in these systems. The calculations use a self-consistent model for the condensation sequence of volatile ices from the nebula gas after refractory (silicate and metal) phases have condensed. The resultant proportions of refractory phases and ices were calculated for a range of nebular temperature structure and redox conditions. Planetesimals in systems with sub-solar C/O should be water ice-rich, with lower than solar mass fractions of refractory materials, while in super-solar C/O systems planetesimals should have significantly higher fractions of refractories, in some cases having little or no water ice. C-bearing volatile ices and clathrates also become increasingly important with increasing C/O depending on the assumed nebular temperatures. These compositional variations in early condensates in the outer portions of the nebula will be significant for the equivalent of the Kuiper Belt in these systems, icy satellites of giant planets and the enrichment (over stellar values) of volatiles and heavy elements in giant planet atmospheres.Comment: Accepted for publication in The Astrophysical Journa

Development of a High Resolution Weather Forecast Model for Mesoamerica Using the NASA Nebula Cloud Computing Environment

Over the past two years, scientists in the Earth Science Office at NASA fs Marshall Space Flight Center (MSFC) have explored opportunities to apply cloud computing concepts to support near real ]time weather forecast modeling via the Weather Research and Forecasting (WRF) model. Collaborators at NASA fs Short ]term Prediction Research and Transition (SPoRT) Center and the SERVIR project at Marshall Space Flight Center have established a framework that provides high resolution, daily weather forecasts over Mesoamerica through use of the NASA Nebula Cloud Computing Platform at Ames Research Center. Supported by experts at Ames, staff at SPoRT and SERVIR have established daily forecasts complete with web graphics and a user interface that allows SERVIR partners access to high resolution depictions of weather in the next 48 hours, useful for monitoring and mitigating meteorological hazards such as thunderstorms, heavy precipitation, and tropical weather that can lead to other disasters such as flooding and landslides. This presentation will describe the framework for establishing and providing WRF forecasts, example applications of output provided via the SERVIR web portal, and early results of forecast model verification against available surface ] and satellite ]based observations

Basal gnathostomes provide unique insights into the evolution of vitamin B12 binders

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Genome Biology and Evolution 7 (2015): 457-464, doi:10.1093/gbe/evu289.The uptake and transport of vitamin B12 (cobalamin; Cbl) in mammals involves a refined system with three evolutionarily related transporters: transcobalamin 1 (Tcn1), transcobalamin 2 (Tcn2), and the gastric intrinsic factor (Gif). Teleosts have a single documented binder with intermediate features to the human counterparts. Consequently, it has been proposed that the expansion of Cbl binders occurred after the separation of Actinopterygians. Here, we demonstrate that the diversification of this gene family took place earlier in gnathostome ancestry. Our data indicates the presence of single copy orthologs of the Sarcopterygii/Tetrapoda duplicates Tcn1 and Gif, and Tcn2, in Chondrichthyes. In addition, a highly divergent Cbl binder was found in the Elasmobranchii. We unveil a complex scenario forged by genome, tandem duplications and lineage-specific gene loss. Our findings suggest that from an ancestral transporter, exhibiting large spectrum and high affinity binding, highly specific Cbl transporters emerged through gene duplication and mutations at the binding pocket.This work was funded by the Fundação para a Ciência e a Tecnologia (FCT) project PEst-C/MAR/LA0015/2013. PhD grant SFRH/BD/84238/2012 awarded to M.L-.M. Postdoctoral grant SFRH/BPD/72519/2010 awarded to R.R

Natural climate solutions

Our thanks for inputs by L. Almond, A. Baccini, A. Bowman, S. CookPatton, J. Evans, K. Holl, R. Lalasz, A. Nassikas, M. Spalding, M. Wolosin, and expert elicitation respondents. Our thanks for datasets developed by the Hansen lab and the NESCent grasslands working group (C. Lehmann, D. Griffith, T. M. Anderson, D. J. Beerling, W. Bond, E. Denton, E. Edwards, E. Forrestel, D. Fox, W. Hoffmann, R. Hyde, T. Kluyver, L. Mucina, B. Passey, S. Pau, J. Ratnam, N. Salamin, B. Santini, K. Simpson, M. Smith, B. Spriggs, C. Still, C. Strömberg, and C. P. Osborne). This study was made possible by funding from the Doris Duke Charitable Foundation. Woodbury was supported in part by USDA-NIFA Project 2011-67003-30205 Data deposition: A global spatial dataset of reforestation opportunities has been deposited on Zenodo (https://zenodo.org/record/883444). This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1710465114/-/DCSupplemental.Peer reviewedPublisher PD

Coordination chemistry of amide-functionalised tetraazamacrocycles: structural, relaxometric and cytotoxicity studies

Three different tetraazamacrocyclic ligands containing four amide substituents that feature groups (namely allyl, styryl and propargyl groups) suitable for polymerisation have been synthesised. Gadolinium(III) complexes of these three ligands have been prepared as potential monomers for the synthesis of polymeric MRI contrast agents. To assess the potential of these monomers as MRI contrast agents, their relaxation enhancement properties and cytotoxicity have been determined. A europium(III) complex of one of these ligands (with propargyl substituents) is also presented together with its PARACEST properties. In addition, to gain further insight into the coordination chemistry of the tetra-propargyl substituted ligand, the corresponding zinc(II) and cadmium(II) complexes have been prepared. The X-ray crystal structures of the tetra-propargyl ligand and its corresponding gadolinium(III), zinc(II) and cadmium(II) complexes are also presented

Feeding the Worlth Healthily: the Challenge of Measuring the effects of Agriculture on Health

Agricultural production, food systems and population health are intimately linked. While there is a strong evidence base to inform our knowledge of what constitutes a healthy human diet, we know little about actual food production or consumption in many populations and how developments in the food and agricultural system will affect dietary intake patterns and health. The paucity of information on food production and consumption is arguably most acute in low- and middle-income countries, where it is most urgently needed to monitor levels of under-nutrition, the health impacts of rapid dietary transition and the increasing ‘double burden’ of nutrition-related disease. Food availability statistics based on food commodity production data are currently widely used as a proxy measure of national-level food consumption, but using data from the UK and Mexico we highlight the potential pitfalls of this approach. Despite limited resources for data collection, better systems of measurement are possible. Important drivers to improve collection systems may include efforts to meet international development goals and partnership with the private sector. A clearer understanding of the links between the agriculture and food system and population health will ensure that health becomes a critical driver of agricultural change

Experience of a Medical Intern in a Secondary Healthcare Hospital in Mexico

In Mexico, medical training consists of 4 or 5 years of studies on a university campus, one year of undergraduate internship and one year of social service. The undergraduate internship is the theoretical-practical academic portion that takes place in the clinical field and is part of the curriculum of the medical career. Normally, students would expect to be able to choose a hospital with subspecialties or with prestige in their region but no matter the type of hospital, the important thing is their attitude towards their work and educatio

Characterizing rhythm in dysarthric speech using the temporal envelope

This study investigated the rhythmic characteristics of 15 dysarthric speakers and 15 non-dysarthric speakers. Speech rhythm was viewed from MacNeilage’s frame/content theory. Specifically, the temporal envelope was analysed. The subjects, native speakers of Canarian Spanish, read four phoneticallybalanced sentences. Five common spectral measures (centroid, spread, rolloff, flatness, and entropy) were computed from the temporal envelope of each sentence. A binomial logistic regression model was built to evaluate how well the five spectral measures can characterize speech rhythm in dysarthric speakers versus the control group. The results show that the dysarthric group present a significantly lower centroid and lower spread. Possible explanations for these results are discussed in relation to previous phonetic studies into the rhythmic speech patterns of dysarthric speakers

Living in Fear: A Labeling Theory Perspective on Undocumented Latinx Workers

The U.S. Latinx (Latin American) undocumented labor force has faced significant and increasing hostility and challenges in recent years. These include harmful labels about their work and personal ethics that lead to inaccurate and racist portrayals. Despite the substantial news and political coverage of this topic in the U.S., there is surprisingly little research on these workers. Guided by Labeling Theory, this thesis is based on in-depth, qualitative interviews with 24 Latinx immigrant workers in Aurora and Denver, Colorado area, who arrived undocumented or overstayed their visas (and became undocumented). The findings include descriptions of the legal and social restrictions imposed on them, their survival techniques, their reasons for migrating to and staying in the U.S., and the collateral effects of the legal restrictions, including access to affordable and adequate healthcare. As expected, the increasing deportation threat directed at the Latinx immigrants posed by the Trump presidency, and the ensuing media, societal, and legal hype, resulted in significant harm to these individuals, including fear in general, and exploitation and abuse in these laborers’ work environments