256 research outputs found

    A New Deal for Southeastern Archaeology, by Edwin A. Lyon, The University of Alabama Press

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    In the 1950s, the Era of the Great Depression, archaeology in the United States enjoyed an enormous boost, both in the substance of its findings on the Precolumbian past and in the development of its methods and proce­dures. Edwin A. Lyon has laid out the story of all this in a book that is a major contribution to the history of the archaeological discipline in this country. The context of this story is in the American South, most specifically the Southeastern United States, or the 'Old South', that part of the country that was the heart of the Confederacy; and it is important to remember that the South has had a history significantly separate and distinct from that of the rest of the nation. This separateness, rooted in its plantation economy and the associated institution of slavery, was further fostered by the Civil War and its aftermath of hardships. These hardships lasted until the 1930s and the economic depression when they began to be ameliorated by the Rooseveltian political and socioeconomic measures known collectively as the 'New Deal'. The policies of the New Deal began those transformations which continued through World War II and beyond. Crucial to these transformations were the building of power dams and rural electrification, soil erosion control and agricultural modernization, and a host of public building programs. All of this went forward with Federal Relief employment. Less tangible but nonetheless important benefits were in the cultural sphere: the arts, drama, writing. history - and of particular importance to us here. archaeology

    Citrobacter rodentium is an unstable pathogen showing evidence of significant genomic flux.

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    Citrobacter rodentium is a natural mouse pathogen that causes attaching and effacing (A/E) lesions. It shares a common virulence strategy with the clinically significant human A/E pathogens enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC) and is widely used to model this route of pathogenesis. We previously reported the complete genome sequence of C. rodentium ICC168, where we found that the genome displayed many characteristics of a newly evolved pathogen. In this study, through PFGE, sequencing of isolates showing variation, whole genome transcriptome analysis and examination of the mobile genetic elements, we found that, consistent with our previous hypothesis, the genome of C. rodentium is unstable as a result of repeat-mediated, large-scale genome recombination and because of active transposition of mobile genetic elements such as the prophages. We sequenced an additional C. rodentium strain, EX-33, to reveal that the reference strain ICC168 is representative of the species and that most of the inactivating mutations were common to both isolates and likely to have occurred early on in the evolution of this pathogen. We draw parallels with the evolution of other bacterial pathogens and conclude that C. rodentium is a recently evolved pathogen that may have emerged alongside the development of inbred mice as a model for human disease

    Molecular transformation and degradation of refractory dissolved organic matter in the Atlantic and Southern Ocean

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    More than 90% of the global ocean dissolved organic carbon (DOC) is refractory, has an average age of 4,000–6,000 years and a lifespan from months to millennia. The fraction of dissolved organic matter (DOM) that is resistant to degradation is a long-term buffer in the global carbon cycle but its chemical composition, structure, and biochemical formation and degradation mechanisms are still unresolved. We have compiled the most comprehensive molecular data set of 197 Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses from solid-phase extracted marine DOM covering two major oceans, the Atlantic sector of the Southern Ocean and the East Atlantic Ocean (ranging from 50° N to 70° S). Molecular trends and radiocarbon dating of 34 DOM samples (comprising Δ14C values from -229 to -495‰) were combined to model an integrated degradation rate for bulk DOC resulting in a predicted age of >24 ka for the most persistent DOM fraction. First order kinetic degradation rates for 1,557 mass peaks indicate that numerous DOM molecules cycle on timescales much longer than the turnover of the bulk DOC pool (estimated residence times of >100 ka) and the range of validity of radiocarbon dating. Changes in elemental composition were determined by assigning molecular formulae to the detected mass peaks. The combination of residence times with molecular information enabled modelling of the average elemental composition of the slowest degrading fraction of the DOM pool. In our dataset, a group of 361 molecular formulae represented the most stable composition in the oceanic environment (“island of stability”). These most persistent compounds encompass only a narrow range of the elemental ratios H/C (average of 1.17 ± 0.13), and O/C (average of 0.52 ± 0.10) and molecular masses (360 ± 28 and 497 ± 51 Da). In the Weddell Sea DOC concentrations in the surface waters were low (46.3 ± 3.3 μM) while the organic radiocarbon was significantly more depleted than that of the East Atlantic, indicating average surface water DOM ages of 4,920 ± 180 a. These results are in accordance with a highly degraded DOM in the Weddell Sea surface water as also shown by the molecular degradation index IDEG obtained from FT-ICR MS data. Further, we identified 339 molecular formulae which probably contribute to an increased DOC concentration in the Southern Ocean and potentially reflect an accumulation or enhanced sequestration of refractory DOC in the Weddell Sea. These results will contribute to a better understanding of the persistent nature of marine DOM and its role as an oceanic carbon buffer in a changing climate

    Exercise and Type 2 Diabetes: The American College of Sports Medicine and the American Diabetes Association: joint position statement

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    Although physical activity (PA) is a key element in the prevention and management of type 2 diabetes, many with this chronic disease do not become or remain regularly active. High-quality studies establishing the importance of exercise and fitness in diabetes were lacking until recently, but it is now well established that participation in regular PA improves blood glucose control and can prevent or delay type 2 diabetes, along with positively affecting lipids, blood pressure, cardiovascular events, mortality, and quality of life. Structured interventions combining PA and modest weight loss have been shown to lower type 2 diabetes risk by up to 58% in high-risk populations. Most benefits of PA on diabetes management are realized through acute and chronic improvements in insulin action, accomplished with both aerobic and resistance training. The benefits of physical training are discussed, along with recommendations for varying activities, PA-associated blood glucose management, diabetes prevention, gestational diabetes mellitus, and safe and effective practices for PA with diabetes-related complications

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    The Convergence of Humanistic and Scientific Approaches in Maya Archaeology

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    Las investigaciones sobre la arqueología maya tradicionalmente iban desarrollándose a través de estudios 'humanísticos' del arte, la arquitectura, la escritura jeroglífica y del Sistema calendárico. En las décadas recientes, sin embargo, tendieron a dominar este campo aproximaciones 'científicas', como lo son los estudios de patrones de población, evaluaciones demográficas, análisis de subsistencia y similares. Aquí sostenemos la tesis de que entre criterios 'humanísticos' y 'científicos' no necesariamente ha de darse una dicotomía y que los dos no entran en conflicto. Las investigaciones mayas recientes más bien demostraron cómo estos dos enfoques convergieron para esclarecer problemas de economía agrícola, contactos externos o foráneos, de ideologías y de organización socio-política

    Some Thoughts on the Chronological-Developmental Configuration of Lower Central American Cultures

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    Un esquema cronológico-evolucional o cultural satisfactorio para Panamá, Costa Rica, Nicaragua así como para la mayor parte de Honduras y El Salvador, agrupados por el autor bajo la denominación Lower Central America, aguarda aún su elaboración. Se enfocan ciertas paralelas y diferencias entre las culturas de Mesoamérica y Lower Central America y se intenta un esquema de la situación cultural del último área. Desde el punto de vista de las formas socio-políticas consiguientes, las culturas de Lower Central America no parecen haber experimentado un desarrollo más allá del tipo de organización caciquil
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