965 resultados para Hoy, George W.
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BACKGROUND Antiretroviral drugs have been shown to reduce risk of mother-to-child transmission of human immunodeficiency virus (HIV) and are also widely used for post-exposure prophylaxis for parenteral and sexual exposures. Sexual transmission may be lower in couples in which one partner is infected with HIV and the other is not and the infected partner is on antiretroviral therapy (ART). OBJECTIVES To determine if ART use in an HIV-infected member of an HIV-discordant couple is associated with lower risk of HIV transmission to the uninfected partner compared to untreated discordant couples. SEARCH METHODS We used standard Cochrane methods to search electronic databases and conference proceedings with relevant search terms without limits to language. SELECTION CRITERIA Randomised controlled trials (RCT), cohort studies and case-control studies of HIV-discordant couples in which the HIV-infected member of the couple was being treated or not treated with ART DATA COLLECTION AND ANALYSIS: Abstracts of all trials identified by electronic or bibliographic scanning were examined independently by two authors. We initially identified 3,833 references and examined 87 in detail for study eligibility. Data were abstracted independently using a standardised abstraction form. MAIN RESULTS One RCT and nine observational studies were included in the review. These ten studies identified 2,112 episodes of HIV transmission, 1,016 among treated couples and 1,096 among untreated couples. The rate ratio for the single randomised controlled trial was 0.04 [95% CI 0.00, 0.27]. All index partners in this study had CD4 cell counts at baseline of 350-550 cells/µL. Similarly, the summary rate ratio for the nine observational studies was 0.58 [95% CI 0.35, 0.96], with substantial heterogeneity (I(2)=64%). After excluding two studies with inadequate person-time data, we estimated a summary rate ratio of 0.36 [95% CI 0.17, 0.75] with substantial heterogeneity (I(2)=62%). We also performed subgroup analyses among the observational studies to see if the effect of ART on prevention of HIV differed by the index partner's CD4 cell count. Among couples in which the infected partner had ≥350 CD4 cells/µL, we estimated a rate ratio of 0.12 [95% CI 0.01, 1.99]. In this subgroup, there were 247 transmissions in untreated couples and 30 in treated couples. AUTHORS' CONCLUSIONS ART is a potent intervention for prevention of HIV in discordant couples in which the index partner has ≤550 CD4 cells/µL. A recent multicentre RCT confirms the suspected benefit seen in earlier observational studies and reported in more recent ones. Questions remain about durability of protection, the balance of benefits and adverse events associated with earlier therapy, long-term adherence and transmission of ART-resistant strains to partners. Resource limitations and implementation challenges must also be addressed.Counselling, support, and follow up, as well as mutual disclosure, may have a role in supporting adherence, so programmes should be designed with these components. In addition to ART provision, the operational aspects of delivering such programmes must be considered.
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PURPOSE In patients with hormone-dependent postmenopausal breast cancer, standard adjuvant therapy involves 5 years of the nonsteroidal aromatase inhibitors anastrozole and letrozole. The steroidal inhibitor exemestane is partially non-cross-resistant with nonsteroidal aromatase inhibitors and is a mild androgen and could prove superior to anastrozole regarding efficacy and toxicity, specifically with less bone loss. PATIENTS AND METHODS We designed an open-label, randomized, phase III trial of 5 years of exemestane versus anastrozole with a two-sided test of superiority to detect a 2.4% improvement with exemestane in 5-year event-free survival (EFS). Secondary objectives included assessment of overall survival, distant disease-free survival, incidence of contralateral new primary breast cancer, and safety. RESULTS In the study, 7,576 women (median age, 64.1 years) were enrolled. At median follow-up of 4.1 years, 4-year EFS was 91% for exemestane and 91.2% for anastrozole (stratified hazard ratio, 1.02; 95% CI, 0.87 to 1.18; P = .85). Overall, distant disease-free survival and disease-specific survival were also similar. In all, 31.6% of patients discontinued treatment as a result of adverse effects, concomitant disease, or study refusal. Osteoporosis/osteopenia, hypertriglyceridemia, vaginal bleeding, and hypercholesterolemia were less frequent on exemestane, whereas mild liver function abnormalities and rare episodes of atrial fibrillation were less frequent on anastrozole. Vasomotor and musculoskeletal symptoms were similar between arms. CONCLUSION This first comparison of steroidal and nonsteroidal classes of aromatase inhibitors showed neither to be superior in terms of breast cancer outcomes as 5-year initial adjuvant therapy for postmenopausal breast cancer by two-way test. Less toxicity on bone is compatible with one hypothesis behind MA.27 but requires confirmation. Exemestane should be considered another option as up-front adjuvant therapy for postmenopausal hormone receptor-positive breast cancer.
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Formative cell divisions are critical for multicellular patterning. In the early plant embryo, such divisions follow from orienting the division plane. A major unanswered question is how division plane orientation is genetically controlled, and in particular whether this relates to cell geometry. We have generated a complete 4D map of early Arabidopsis embryogenesis and used computational analysis to demonstrate that several divisions follow a rule that uses the smallest wall area going through the center of the cell. In other cases, however, cell division clearly deviates from this rule, which invariably leads to asymmetric cell division. By analyzing mutant embryos and through targeted genetic perturbation, we show that response to the hormone auxin triggers a deviation from the ``shortest wall'' rule. Our work demonstrates that a simple default rule couples division orientation to cell geometry in the embryo and that genetic regulation can create patterns by overriding the default rule.
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Morphogenesis occurs in 3D space over time and is guided by coordinated gene expression programs. Here we use postembryonic development in Arabidopsis plants to investigate the genetic control of growth. We demonstrate that gene expression driving the production of the growth-stimulating hormone gibberellic acid and downstream growth factors is first induced within the radicle tip of the embryo. The center of cell expansion is, however, spatially displaced from the center of gene expression. Because the rapidly growing cells have very different geometry from that of those at the tip, we hypothesized that mechanical factors may contribute to this growth displacement. To this end we developed 3D finite-element method models of growing custom-designed digital embryos at cellular resolution. We used this framework to conceptualize how cell size, shape, and topology influence tissue growth and to explore the interplay of geometrical and genetic inputs into growth distribution. Our simulations showed that mechanical constraints are sufficient to explain the disconnect between the experimentally observed spatiotemporal patterns of gene expression and early postembryonic growth. The center of cell expansion is the position where genetic and mechanical facilitators of growth converge. We have thus uncovered a mechanism whereby 3D cellular geometry helps direct where genetically specified growth takes place.
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statement of G. W. Pieritz
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Morphogenesis emerges from complex multiscale interactions between genetic and mechanical processes. To understand these processes, the evolution of cell shape, proliferation and gene expression must be quantified. This quantification is usually performed either in full 3D, which is computationally expensive and technically challenging, or on 2D planar projections, which introduces geometrical artifacts on highly curved organs. Here we present MorphoGraphX (www.MorphoGraphX.org), a software that bridges this gap by working directly with curved surface images extracted from 3D data. In addition to traditional 3D image analysis, we have developed algorithms to operate on curved surfaces, such as cell segmentation, lineage tracking and fluorescence signal quantification. The software’s modular design makes it easy to include existing libraries, or to implement new algorithms. Cell geometries extracted with MorphoGraphX can be exported and used as templates for simulation models, providing a powerful platform to investigate the interactions between shape, genes and growth.DOI: http://dx.doi.org/10.7554/eLife.05864.001Author keywordsResearch organism
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5 Briefe mit Antwort an Inga Haag, 1951-1955; 1 Brief mit Antwort von Jürgen Habermas an Max Horkheimer, 1955; 1 Brief von Ministerialrat i. R. Theodor Häbich an Max Horkheimer, 1957; 2 Briefe mit Antwort von cand. phil. Walter Hähnle an Max Horkheimer, 1955, 1957; 1 Brief mit Antwort von Sekretärin Jutta Hagen an Max Horkheimer, 1956; 1 Dissertationsauszug von Volker Freiherr von Hagen, 1954; 1 Brief mit Antwort von Julia Hagenbucher an Max Horkheimer, 1951/1952; 1 Entwurf zu einem Gratulationsschreiben von Max Horkheimer an Professor Otto Hahn, ohne Jahr; 2 Drucksachen von Obermagistratsrat Julius Hahn, 1953, 1955; 1 Brief mit Antwort von Theodor W. Adorno, von Dr. Hans Hahn an Max Horkheimer, 1952; 1 Brief von Theodor W. Adorno an Dr. Hans Hahn, 1952; 1 Danksagung von Rabbi Hugo Hahn, 1955; 3 Briefe mit Antwort von Paul Hahn an Max Horkheimer, 1951-1958; 1 Brief von Max Horkheimer an die Gebrüder Haldy, 1952; 1 Brief mit Antwort und Beilage von Professor George W. F. Hallgarten an Max Horkheimer, 1950; 1 Rundschreiben von Arzt und Psychotherapeut Hans Hammer, 1957; 1 Brief von Max Horkheimer an Margarete Hampf-Solm, 1955; 1 Brief mit Antwort von Professor Eduardo Hamuy an Max Horkheimer, 1952; 1 Brief von der Stadtärztin Dr. med. Carola Hannappel an Max Horkheimer, 1951; 1 Brief von Hansenmeister an Max Horkheimer, 1951; 1 Brief mit Antwort und Beilage von der Buchhandlung Ludwig Häntzschel an Max Horkheimer, 1958; 1 Brief von Professor Frederick Harris Harbison an Max Horkheimer, 1952; 3 Briefe mit Antwort von Robert Harcourt an Max Horkheimer, 1958; 1 Brief von Karl Hardach an Max Horkheimer, 1957; 1 Brief mit Antwort von Emilie Harlacher an Max Horkheimer, 1952; 1 Drucksache mit Antwort von Oberkirchenrat Otto L. A. von Harling an Max Horkheimer, 1955; 1 Brief mit Antwort von Gertrud Harms an Max Horkheimer, 1955; 2 Brief mit Antwort von Professor Wolfgang Hartke an Max Horkheimer, 1954-1956; 2 Briefe mit antwort von Max Horkheimer an Senator Georg Hartmann, 1951, 1954; 3 briefe mit Antwort und Beilage von Ökonom Heinz Hartmann an Max Horkheimer, 1956-1958; 1 Brief mit Antwort von Professor Wilbert E. Moore an Max Horkheimer, 1957; 3 Briefe mit Antwort und Beilage von Dr. phil. Leo Hartmann an Max Horkheimer, 1957-1858; 1 Brief mit Antowort von Dr. phil. Eckardt Mesch an Max Horkheimer, 1957; 1 Brief mit Antwort von Luzie Hatch an Max Horkheimer, 1954; 1 Brief von Max Horkheimer an den Direktor H. W. Haupt, 1950; 1 Drucksache von Haus Schwalbach, 1951; 4 Briefe mit Antwort von Professor Gottfried und Ellen Hausmann an Max Horkheimer, 1951-1958; 6 Briefe mit Antwort von Eva Haussner an Max Horkheimer, 1957, 1958; 1 Brief mit Antwort von Professor Robert J. Havighurst an Max Horkheimer, 1951; 1 Brief mit Beilage von Herbert Hax an Max Horkheimer, 1955; 2 Briefe mit Antwort und Beilage von Jean Louis Hébarre an Max Horkheimer, 1950-1952; 1 Brief mit Antwort von dem Hebedienst für Elektrizität, Gas und Wasser an Max Horkheimer, 1951; 5 Briefe mit Antwort und Beilage von Professor Otto Heckmann an Max Horkheimer, 1952, 1954; 1 Brief von Melvin J. Lasky an August Heckscher, 1957; 3 Briefe mit Antwort von Marie Heep an Max Horkheimer, 1956-1858; 1 Brief von der Buchhandlung Thekla Heer an Max Horkheimer, 1953; 1 Brief mit Antwort von dem Verleger Jakob Hegner an Max Horkheimer, 1955; 1 Brief von Dr. phil. Rudolf M. Heilbrunn an Max Horkheimer, 1953; 1 Brief mit Antwort von Professor Eduard Heimann an Max Horkheimer, 1952; 1 Brief von Professor Eduard Heimann an Theodor W. Adorno, 1957; 1 Brief mit Antwort von stud. phil. Wolfgang Heinrich an Max Horkheimer, 1958; 1 Brief von Max Horkheimer an den Direktor Helmuth Heintzmann, 1955; 1 Aktennotiz von Professor Bernhard Heller, 1956; 1 Brief mit Antwort von Philipp A. Heller an Max Horkheimer, 1952; 1 Brief von Max Horkheimer an Assistent Winfried Hellmann, 1957; 2 Briefe mit Antwort von Professor Arthur Henkel an Max Horkheimer, 1953/1954; 1 Brief von Max Horkheiemr an Dorothy Henkel, 1952; 2 Briefe mit Antwort von Dr. jur. Werner Hennig an Max Horkheimer, 1951; 1 Brief von Max Horkheimer an Professor Wilhelm Hennis, 1957; 3 Briefe mit Antwort und Beilage von Professor Fritz Hepner an Max Horkheimer, 1953; 1 Brief von Max Horkheimer an den Hessischer Minister für Erziehung und Volksbildung, 1950; 1 Brief mit Antwort von Professor Henrietta Herbolsheimer an Max Horkheimer, 1957/1958; 2 Briefe mit Antwort von P. G. Herbst an Max Horkheimer, 1952; 1 Brief von Max Horkheimer an den Herder Verlag, 1953; 2 Briefe mit Antwort, Beilagen und Aktennotizen von Guenter R. Herz an Max Horkheimer, 1956-1957; 2 Briefe mit Antwort unv Beilagen von Professor Theodor W. Adorno, von Dr. phil. Günther Herzberg an Max Horkheimer, 1951-1953; 1 Brief von Professor Theodor W. Adrono an Dr. phil. Günther Herzberg, 1951; 1 Brief von Dr. phil. G. Herzfeld an Max Horkheimer, 1952; 1 Brief von dem Herzog-Film an Max Horkheimer, 1952; 1 Brief mit Antwort von Professor Theodor W. Adorno, von Professor Erich Herzog an Max Horkheimer, 1952; 1 Brief von Professor Theodor W. Adorno an Professor Erich Herzog, 1952; 1 Brief mit Antwort von dem Verlag Otto H. Hess an Max Horkheimer, 1954; 1 Brief von Professor Gerhard Hess an Max Horkheimer, 1953; 1 Drucksachevon dem Hessischer Arbeitsausschuss gegen Rekrutierung, 1952; 1 Brief mit Beilage von dem Hotel Hessischer Hof an Max Horkheimer, 1956; 1 Brief mit Antwort von dem Hessischer Landesverband für Erwachsenenbildung an Max Horkheimer, 1956; 2 Briefe mit Antwort und Beilage von Marc Heurgon an Max Horkheimer, 1958; 1 Brief mit Beilage von Ruth Heydebrand an Max Horkheimer, [1955]; 1 Brief mit Antwort von Professor Frederick W. J. Heuser an Max Horkheimer, 1954; 2 Briefe mit Antwort von Professor Joh Erich Heyde an Max Horkheimer, 1958; 1 Befürwortung von Wolf von Heydebrand an Max Horkheimer, 1954; 1 Brief mit Antwort von Professor Heinz Joachim Heydorn an Max Horkheimer, 1953; 1 Brief mit Antwort und Beilage von dem Arzt Otto Heymann an Max Horkheimer, 1955; 5 Briefe zwischen dem Devisenberater und Steuerhelfer Joseph Christ und Max Horkheimer, 1955, 1956, 1961; 1 Brief von dem Office of the United States High Commissioner for Germany an Max Horkheimer, 1953; 1 Lebenslauf von Elen B. Hill, ohne Jahr; 1 Brief von Kurt H. Wolff an Max Horkheimer, 1952; 1 Brief von Rolf Himmelreich an Max Horkheimer, 1956; 1 Brief mit Antwort von Dr. Rolf Hinder an Max Horkheimer, 1953; 1 Brief mit Antwort von Anton Hinsinger an Max Horkheimer, 1953; 1 Brief mit Antwort von dem Hippokrates-Verlag an Max Horkheimer, 1952; 1 Brief von Bernice L. Hirsch anMax Horkheimer, 1957; 4 Briefe und Beilagen zwischen dem Historiker und Soziologe Helmut Hirsch an Max Horkheimer, 1951-1954, 25.05.1951; 3 Briefe mit Antwort von Lux Hirsch an Max Horkheimer, 1958; 1 Brief mit Antwort von Trude Hirschberg an Max Horkheimer, 1951; 1 Brief mit Antwort von Ingineur Paul F. Hirschfelder an Max Horkheimer, 1952; 1 Brief von Johannes Hirzel an Max Horkheimer, 1955; 1 Brief mit Antwort von dem Historisches Seminar Köln an Max Horkheimer, 1956; 1 Brief mit Antwort und Beilage von Professor Wolfgang Hochheimer an Professor Theodor W. Adorno, 1952; 2 Briefe von Max Horkheimer an Professor Wolfgang Hochheimer, 1953, 1954; 2 Memoranden von der Deutschen Gesellschaft für Psychologie, 1953; 1 Brief mit Beilage von Stud. phil. Erna Hochleitner an Max Horkheimer, 1956; 1 Brief mit Antwort von Professor Helmut Coing an Max Horkheimer, 1957; 3 Briefe mit Antwort von der Hochschule für Sozialwissenschaften Wilhelmshaven an Max Horkheimer, 1957, 1958; 1 Brief von Max Horkheimer an die Hochschule für Wirtschafts- und Sozialwissenschaften Nürnberg, 1953; 2 Drucksachen von dem Hochschul-Dienst, 1952; 2 Drucksachen von der Hochschule für politische Wissenschaften München, 1952; 1 Brief mit Antwort von Dr. Wolfram Hodermann an Max Horkheimer, 1951; 4 Briefe zwischen Dr. phil. Walter Höllerer und Max Horkheimer, 1956; 1 Brief mit Antwort von Privatdozent Dr. phil. Walter Hoeres anMax Horkheimer, 1956; 2 Briefe mit Antwort von Stud. phil. Charlotte Hoffmann an Max Horkheimer, 1950; 3 Briefe mit Antwort und Beilage von Professor Walter Hoffmann an Max Horkheimer, 1950-1955; 1 Brief mit Antwort von Wolfhart E. V. Hoffmann an Max Horkheimer, 1953; 1 Brief von Max Horkheimer an Dr. Werner Hofmann, 1956; 1 Glückwunschtelegramm mit Antwort von Ernst und Karl Hohner, 1953; 1 Brief von Dozent Uvo Hölscher an Max Horkheimer, 1950; 2 Briefe mit Antwort von Professor Dr. med. K. Holldack an Max Horkheimer, 1957; 2 Briefe mit Antwort von Dipl. Landwirt Bernhard Hollenhorst an Max Horkheimer, 1956; 1 Brief von Hans Heinz Holz an Max Horkheimer, 1951; 2 Briefe mit Antwort und Beilage von Dr. phil. Rudolf Holzinger an Max Horkheimer, 1951, 1952; 1 Brief mit Antwort von Jakob Hommen an Max Horkheimer, 1953; 1 Brief von Adele Hoppe anMax Horkheimer, 1953; 1 Brief mit Antwort von Dr. jur. Anton Horn an Max Horkheimer, 1954; 1 Brief mit Antwort von Dr. phil. Emil Horn an Max Horkheimer, 1953; 1 Brief von der Landesabgeordneten Ruth Horn an H. Maidon, 1953; 1 Brief mit Antwort von Reg.-Direktor Dr. phil. Kurt Horstmann an Max Horkheimer, 1953; 1 Brief von dem Hotel Baur au Lac an H. Maidon, 1958; 2 Briefe mit 1 Antwort von dem Hotel Frankfurter Hof an Max Horkheimer, 1956, 1958; 1 Brief mit Antwort von dem Hotel Stafflenberg an H. Maidon, 1953; 1 Brief von dem Hotel Vier Jahreszeiten, München an Max Horkheimer, 1951; 1 Brief von Max Horkheimer an Jean J. Hubener, 1951; 2 Briefe mit Antwort und Beilage von Susanna Huber-Weisser an Max Horkheimer, 1956; 1 Todesanzeige von dem Sozialgerichtsdirektor Gustav Adolf Hünniger, 1955; 1 Brief von dem Oberstudiendirektor F. Huf an Max Horkheimer, 1952; 1 Brief mit Antwort von Professor H. D. Huggins an Max Horkheimer, 1954; 2 Briefe mit 1 Antwort und 1 Beilage von dem Humboldt-Verlag, Wien-Stuttgart an Max Horkheimer, 1951; 1 Brief von Helge Pross an stud. rer. pol. Kristian Hungar, 1957; 1 Brief von Helmut Hungerland an Max Horkheimer, 1950; 1 Brief mit Antwort von James R. Huntley an Max Horkheimer, 1954; 1 Brief von Professor Robert Maynard Hutchins an Max Horkheimer, 1957;
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President George W. Bush's 2001 statement, which laid out guidelines for research that uses human embryonic stem cells to qualify for federal funding, intends to prevent new embryonic stem cell lines from being developed, by prohibiting the federal funding of research that uses embryonic stem cell lines other than those that existed at the time of the policy's inception and were approved by the National Institutes of Health. This policy raises questions of medical and technological ethics and the governments' role in making decisions regarding the advancement of science based on moral and political opinions. Federal stem cell usage policy directly affects scientific research efforts that are currently on the path to understanding the mechanisms of cell differentiation and could potentially offer answers and therapies for disabilities and many chronic diseases. By reviewing the current literature on the background information on human embryonic stem cells, including what they are, where they come from, how they are used for research purposes, and the ethical controversy surrounding their use, I have researched and reported the impact of the 2001 policy on medical research. ^ Both those who support the current policy on human embryonic stem cell research and those who are advocates for policy change have relevant arguments and varying opinions on human embryonic stem cell usage itself. The ethical implication of how embryonic stem cells are obtained has led to fierce debate. This paper presents many arguments for and against hESC research in addition to the policy governing their use. This analysis concludes that the current policy on federal funding of human embryonic stem cell research should be revised to allow research using new stem lines to be eligible for federal funding under specific guidelines. Supporting evidence for this recommendation is provided.^
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The eighteenth annual biochemical engineering symposium was held during April 22–23, 1988 at the YMCA of the Rockies conference center in Estes Park, Colorado, under the sponsorship of the University of Colorado. Previous symposia in this series have been hosted by Kansas State University (1st, 3rd, 5th, 9th, 12th, 16th), University of Nebraska-Lincoln (2nd, 4th), Iowa State University (6th, 7th, l0th, 13th, 17th), University of Missouri–Columbia (8th, 14th), and Colorado State University (11th, 15th). Next year's symposium is scheduled to be held at the University of Missouri-Columbia. The symposia are devoted to talks by students about their ongoing research. Because final publication usually takes place elsewhere, the papers included in the proceedings are brief, and often cover work in progress. ContentsApplications of mass spectrometers in biochemical engineeringJohn P. McDonald, Ayush Gupta, and Lourdes Taladriz, Kansas State University Enzymatic hydrolysis of corn gluten proteinsJulie Hardwick; Iowa State University Improved Acetone-Butanol Fermentation AnalysisZ. Buday; Colorado State University On-Line State Identification for Batch FermentationD. A. Gee and W. F. Ramirez; University of Colorado Role of Spargers in Air-Lift ReactorsPeter U. Sohn and Rakesh K. Bajpai; University of Missouri–Columbia The Interaction of Microcarriers and Turbulence within an Airlift FermenterG. Travis Jones; Kansas State University Oxygen Diffusion in the Inter-Fiber Gel/Cell Matrix of NMR-Compatible Hollow Fiber Bio-ReactorsS. L. Hanson, B. E. Dale, and R. J. Gillies; Colorado State University Characterization of Ca-alginate Gel Beads FormationHorngtwu Su, Rakesh K. Bajpai, and George W. Preckshot; University of Missouri–Columbia Metabolic Effects of Chloramphenicol Resistance in the Recombinant Host/Vector System: E. coli RRl [pBR329]William E. Bentley, Dana C. Andersen, Dhinakar S. Kompala, and Robert H. Davis; University of Colorado Genetic Engineering of Beta-Galactosidase to Aid in Fermentation Product Recovery by Polyelectrolyte PrecipitationD. E. Parker, C. E. Glatz, J. Zhao, C. F. Ford, S. M. Gendel, and M. A. Rougvie; Iowa State University Biodegradation of Organic Compounds in SoilLourdes Taladriz, L. E. Erickson, and L. T. Fan; Kansas State University Effect of Dilution, pH and Nutrient Composition on the Biodegradation of Metalworking FluidsAyush Gupta, L. E. Erickson, and L. T. Fan; Kansas State University Dissolved Hydrogen Correlation with Redox Potential in Acetone-Butanol FermentationXiangdong Zhou; Colorado State University Modeling of Ensiling Fermentation of Sweet SorghumA. K. Hilaly; Colorado State University
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Luego de las resistencias que George W. Bush generó en la región, la llegada de Barack Obama despertó esperanzas en algunos mandatrios latinoamericanos. En el presente artículo analizamos el vínculo entre Estados Unidos y el resto del continente, a partir del análisis de las últimas dos Cumbres de las Américas: la de Puerto España (2009), en la que primó la expectativa por la relación entre iguales que prometió el recién asumido presidente demócrata; y la de Cartagena (2012), cuando emergió una nueva agenda impuesta por América Latina, pese a las presiones de Washington. Estas cumbres se inscriben en diferentes etapas de la relación entre Estados Unidos y el resto del Hemisferio, que muestran alcances y límites de las estrategias de la Casa Blanca, y reconfiguraciones regionales para enfrentar el poder de Estados Unidos.
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Este trabajo está destinado a divulgar en la población de las carreras de inglés como lengua extranjera un enfoque al estudio del discurso que reconoce su carácter situado tanto en sentido local como histórico. Su objetivo específico es revelar las características del género ‘alocución inaugural’ y la construcción discursiva de la nación estadounidense a través del análisis de un discurso público importante desde el punto de vista histórico pronunciado por el presidente de los EE.UU. George W. Bush. El examen de los datos muestra que la concurrencia de rasgos de actuación oral y eficaces recursos retóricos en un texto cuidadosamente elaborado que convoca ciertos aspectos de la identidad nacional se orienta a complejos fines políticos y se dirige a múltiples auditorios.
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Analyses of water samples taken by means of an in-hole sampler generally show good agreement with analyses of samples collected by routine shipboard squeezing techniques. At Sites 438 and 439, a decrease in salinity with depth is related to former freshwater flow from an aquifer that crops out at an anticline on a deep sea terrace between Japan and the top of the trench slope of the Japan Trench. This former subaerial recharge suggests significant late Cenozoic subsidence of the terrace, because it now lies at a water depth of 1500 meters. Samples from the trench slope at Site 440 have extremely high values of alkalinity and ammonia, presumably because of a favorable combination of high sedimentation rate and organic carbon content. Diagenetic conditions on the trench slope favor formation of the Fe-Mg carbonate mineral, ankerite; at Site 440 it first occurs at a depth below the sea floor of only 29 meters in late Pleistocene strata. Undissolved diatoms persist to relatively great depth at the sites of Leg 57 because of a low geothermal gradient caused by subduction. Secondary silica lepispheres first appear at 851 meters at the most landward and warmest site, Site 438, in strata 16 million years old with an ambient temperature of 31 °C.
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Dating of a hornblende concentrate by the 40Ar/39Ar method gives an age of 23.4±5.5 m.y. for a dacite boulder from conglomerate in Deep Sea Drilling Project Hole 439. The conglomerate clasts range up to 1 meter in diameter and are nearly monolithologic, suggesting that a nearby former volcano erupted the dacite. The dacite is only 90 km landward from the Japan Trench, whereas modern trench-related volcanoes lie at least 120 km from their trenches. The dacite locality is on strike with and is probably an extension of a magmatic arc on the island of Hokkaido that crosses the Kuril arc at an angle of 65° and which was active 16 to 36 m.y. ago. The part of the former arc landward from the Kuril arc argues against an origin from a leaking subduction zone or from subduction of an active spreading ridge. The part seaward both from the Kuril and Japan arcs weakens an explanation based on migration of a trench-trenchtrench triple junction. The magmatic rocks probably formed along a middle-Tertiary plate boundary that had stepped seaward from a more-landward Cretaceous position. Later, the boundary stepped farther seaward at the Kuril arc and landward again at the Japan arc. If so, the present Japan subduction zone must have consumed most of the strata that had accumulated between it and the earlier trench.
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On Deep Sea Drilling Project Leg 54, we recovered upper Pliocene (Globigerinoides obliquus: PL6 zone) to Pleistocene sediments from the equatorial East Pacific Rise (EPR) and Galapagos spreading center (GSC). Progressively older sediments were drilled at increasing distances from the crest, with the exception of the sediment drilled in the deepest trough known in the Siqueiros fracture zone. The anomalous age obtained at the latter site suggests that the basalt which was drilled may represent fracture zone volcanism. Paleoenvironmental analysis using the planktonic foraminifers at the EPR sites indicated the presence of environmental cycles of shorter wave length during the interval from 0 to 0.24 Ma, whereas cycles of longer wave length occurred from 0.43 to 2.17 Ma. The planktonic foraminiferal taphocoenoses at the EPR sites were strongly affected by selective dissolution which indicated that these EPR sites have been near either the lysocline or carbonate compensation surface since the upper Pliocene. The planktonic foraminiferal thanatocoenoses at the GSC sites were preserved better than those at the EPR sites. The number of planktonic foraminiferal species generally was greatly reduced in the green mud associated with the GSC hydrothermal mounds. More species were found in older than in younger green mud; this suggests that there probably was an increase in the rate of production of green mud sometime after the initiation of the hydrothermal system.