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An Indoor Radon Survey in Three Different Climate Regions in Mexico, and the Influence of Climate in the Obtained Values  [PDF]
Guillermo Espinosa, Richard Gammage
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.29133
Abstract: In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor radon concentrations, the country was divided into three climate regions: the northern semi-desert region, the central semitropical region and the southern tropical region. The survey was carried out using nuclear track methodology. The dosimeters employed for the survey were based on the passive closed-end cup device, developed at the Physics Institute of the National Autonomous University of Mexico, and used PADC as detector material. A well-established protocol for chemically etching and reading the detectors was followed. Average annual temperatures differ between regions (from 15℃ to 28℃) but vary relatively little within each region. Atmospheric temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations because temperature largely determines building ventilation habits, and ventilation habits are known to have significant effects on indoor radon concentrations. Other factors, including building construction materials, architectural styles, geological and hydrological characteristics, and seismicity, vary from region to region and within each region. In each of the three regions low levels of indoor radon (from 37 to 179 Bq·m-3) were found.
The Flypaper and Teflon Effects: Evidence from China  [PDF]
Lyoe Lee, Guillermo Vuletin
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.37103
Abstract: In this paper, we analyze how public spending responds to income and intergovernmental fiscal transfer shocks in China. Similar to federations around the world, we find the flypaper effect at the provincial level since the country became a de facto federation in 1980. Before 1980 we find what we define as the teflon effect at the central government level. We rationalize the latter regularity using collection costs/distortionary taxation arguments
Some relationships between the geometry of the tangent bundle and the geometry of the Riemannian base manifold
Guillermo Henry,Guillermo Keilhauer
Mathematics , 2009,
Abstract: We compute the curvature tensor of the tangent bundle of a Riemannian manifold endowed with a natural metric and we get some relationships between the geometry of the base manifold and the geometry of the tangent bundle.
Fracture Response of Reinforced Concrete Deep Beams Finite Element Investigation of Strength and Beam Size  [PDF]
Guillermo A. Riveros, Vellore Gopalaratnam
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.411212
Abstract: This article presents a finite element analysis of reinforced concrete deep beams using nonlinear fracture mechanics. The article describes the development of a numerical model that includes several nonlinear processes such as compression and tension softening of concrete, bond slip between concrete and reinforcement, and the yielding of the longitudinal steel reinforcement. The development also incorporates the Delaunay refinement algorithm to create a triangular topology that is then transformed into a quadrilateral mesh by the quad-morphing algorithm. These two techniques allow automatic remeshing using the discrete crack approach. Nonlinear fracture mechanics is incorporated using the fictitious crack model and the principal tensile strength for crack initiation and propagation. The model has been successful in reproducing the load deflections, cracking patterns and size effects observed in experiments of normal and high-strength concrete deep beams with and without stirrup reinforcement.
Blood flow, not hypoxia, determines intramucosal PCO2
Guillermo Gutierrez
Critical Care , 2004, DOI: 10.1186/cc3489
Abstract: Hypotension is strongly associated with poor patient outcome, and reversing this condition clearly should be a primary therapeutic goal when treating patients in the early stages of shock. Potent inotropic and vasoconstrictor agents are de rigueur in the treatment of shock. The therapeutic goal is to maintain the mean arterial pressure at levels above 60 mmHg, a value thought to be the minimal pressure head required for coronary and renal perfusion [1]. Our predicament is how best to determine the mean arterial pressure level that will result in optimal tissue perfusion in a given patient. In other words, is a mean arterial pressure of 60 mmHg sufficient to assure adequate perfusion to all organs? In some patients this accepted minimal mean arterial pressure may not suffice to insure adequate tissue perfusion. Should we aim for higher, or perhaps even lower, mean arterial pressure values? Catecholamines, while extremely useful in treating decreases in cardiac output, may produce an unwelcome increase in myocardial O2 consumption in cardiogenic shock, or may impede blood flow to oxygen-starved tissues in hypovolemic shock [2]. In septic shock, the balance between the positive and the negative effects of vasopressor and inotropic agents are even more difficult to discern [3].A reliable and practical method to detect the onset of tissue hypoxia in critically ill patients would be an invaluable tool in guiding the timing and aggressiveness of resuscitation efforts. Finding such a tool has bedeviled clinical investigators for many years. Given our present level of technology, our options in determining the adequacy of tissue oxygenation in the clinical setting remain limited. Direct measures of tissue oxygen concentration are not sufficient to characterize the complex interaction between cellular energy requirements and oxygen supply. More complex technology, such as magnetic resonance spectroscopy and near-infrared spectroscopy are either insensitive or impractical in t
Baum's Textbook of Pulmonary Diseases, 7th Edition
Guillermo Gutierrez
Critical Care , 2005, DOI: 10.1186/cc3717
Abstract: On the basis of that experience, I have consistently advised our entering pulmonary fellows to read Baum's textbook from cover to cover as an efficient and relatively painless introduction to the pathophysiology and treatment of pulmonary diseases. With each subsequent edition, however, Baum's textbook grew progressively bulkier until it had to be split into two volumes. This change, in my opinion, resulted in the loss of a most endearing attribute, that of being a single-volume compendium of pulmonary medicine easily carried to the office or to an on-call room and read as time permitted.The seventh edition of Baum's textbook is a welcome return to the single-volume format. The editors have completely revamped the previous edition of the book and produced a comprehensive, easy-to-read collection of chapters on pulmonary disorders, while keeping a tight rein on the burgeoning tendencies inherent in any multi-authored book. With the present edition of Baum's textbook, the editors have achieved their aim in producing a focused, highly readable work that serves both as a textbook and desk reference for practitioners of pulmonary medicine at all levels of training.The book's 70 chapters are written by 106 authors, many of them internationally recognized experts in their field. The chapters are grouped into 12 sections ranging from diagnostic methods to respiratory disorders of sleep. There is overall coherence in size and feel of the various chapters, which, with very few exceptions, are clearly written and abundantly referenced. The conciseness of these chapters promotes learning and stimulates the reader to learn about related issues. I found myself jumping from chapter to chapter as my curiosity was piqued. Each chapter includes a critical evaluation of the underlying literature as well as simplified evidence-based medicine tables stating the level of evidence underlying critical recommendations or conclusions, with the prospective, randomized trial considered the hig
Improvement of Escherichia coli production strains by modification of the phosphoenolpyruvate:sugar phosphotransferase system
Guillermo Gosset
Microbial Cell Factories , 2005, DOI: 10.1186/1475-2859-4-14
Abstract: Metabolic engineering can be defined as the purposeful modification of cellular activities with the aim of strain improvement [1]. Development of microbial strains for the production of metabolites is based primarily on the application of recombinant DNA technology to alter the properties of the metabolic network by modifying the level of activity or the properties of specific enzymes. These principles have been applied to the generation of a large number of Escherichia coli strains, designed for the production of commercially important compounds [2]. Cultures with these engineered strains usually employ media containing glucose. This sugar is nowadays the most utilized raw material in industrial fermentations with E. coli, mostly because it is relatively inexpensive and it is the preferred carbon and energy source for this bacterium. As a component of culture media, glucose provides carbon atoms for biomass and product generation. The cell's capacity to uptake and metabolize this carbohydrate has a profound impact on its growth rate and productivity. Thus, it can be expected that modifications to glucose transport systems should have and important impact on the cell's physiology and this, in turn, can either improve or become detrimental in an industrial production context. The purpose of this review is to summarize the characteristics of glucose uptake systems in E. coli and discuss examples where their modification in wild type or engineered production strains has resulted in improved performance.A distinctive feature of E. coli and other gram-negative bacteria is the presence of two concentric membranes surrounding its cytoplasm. The space between these two membranes is the periplasm (Fig. 1). The outer and cytoplasmic membranes constitute a hydrophobic barrier to polar compounds. To control the inward and outward flow of molecules across these barriers, the bacterial cell synthesizes proteins that form channels. The outer membrane constitutes the first barrier
Conference Report: The Nour Foundation Georgetown University & Blackfriars Hall, Oxford University Symposium Series Technology, Neuroscience & the Nature of Being: Considerations of Meaning, Morality and Transcendence Part I: The Paradox of Neurotechnology 8 May 2009
Guillermo Palchik
Philosophy, Ethics, and Humanities in Medicine , 2009, DOI: 10.1186/1747-5341-4-9
Abstract: On May 8, 2009, The Nour Foundation, a public charitable organization and NGO in special consultative status to the United Nations, together with Georgetown University, Blackfriars Hall at Oxford University, and the Potomac Institute for Policy Studies' Center for Neurotechnology Studies, presented The Paradox of Neurotechnology, a thought-provoking symposium exploring the technologies of neuroscience and the ways in which these tools and methods can lead to a deeper understanding of the nature of being. The discussions brought together leaders in the field to address the pressing issues, questions, and potential dilemmas arising in and from the use of neurotechnologies, and how such progress prompts deeper neuroethical considerations. The symposium was the first in a three-part series, with subsequent meetings to be held at the University of Oxford on 22 July 2009, and the United Nations in New York on 11 September 2009. Further information regarding the symposium can be found on their website [1].The symposium began with an introduction and keynote by Prof. James Giordano, Professor of Neuroscience, Ethics, and Philosophy at the Institute for Psychological Sciences, Centre for Philosophical Psychology; Fellow, Blackfriars Hall, University of Oxford; Director of the Center for Neurotechnology Studies and Chair of Academic Programs at the Potomac Institute for Policy Studies in Virginia; and former Samueli-Rockefeller Professor of Medicine and Neuroscience and Director of the Program for Brain, Mind and Healing Research at the Georgetown University Medical Center, where he maintains an adjunct professorship. Giordano set the tone by positing that as we approach the frontier realms of science, we encounter new and novel possibilities that require us to deal with the contingencies arising not only from what is yet unknown, but what may ultimately remain unknowable. He outlined the basic premises of a philosophy of science to address and unify domains of metaphysics, e
La periferia de "la gran transformación": el mercado de tierras en la provincia de Buenos Aires: Los casos de Chascomús y Junín en perspectiva comparada, 1780-1912
Mundo agrario , 2011,
Abstract: in this paper we analyze the formation of the land market during the expansion of the frontier of the province of buenos aires from a local comparative perspective, studying chascomús and junín areas. we postulate that the constitution of the land market in the buenos aires province was a gradual process that began only when the the lands defended by the forts of the internal border were populated and were established certain security guarantees for private property
Los dilemas morales qua límites de la racionalidad práctica
Lariguet, Guillermo;
Diánoia , 2010,
Abstract: in this paper, i attempt to show in what way moral dilemmas can be seen as limits of practical rationality. i distinguish between two types of dilemma: the first type is based in normative requirements that are non defeasible; the second type, prima facie requirements. then, i try to show in what way a rational solution or right answer can be affected by these types of dilemmas. in addition, i discuss dilemmas with tragic elements.
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