搜索结果：Genesis

Abstract ENSO (El Niño–Southern Oscillation) has a large influence on tropical cyclone activity. The authors examine how different environmental factors contribute to this influence, using a genesis potential index developed by Emanuel and Nolan. Four factors contribute to the genesis potential index: low-level vorticity (850 hPa), relative humidity at 600 hPa, the magnitude of vertical wind shear from 850 to 200 hPa, and potential intensity (PI). Using monthly NCEP Reanalysis data in the period of 1950–2005, the genesis potential index is calculated on a latitude strip from 60°S to 60°N. Composite anomalies of the genesis potential index are produced for El Niño and La Niña years separately. These composites qualitatively replicate the observed interannual variations of the observed frequency and location of genesis in several different basins. This justifies producing composites of modified indices in which only one of the contributing factors varies, with the others set to climatology, to determine which among the factors are most important in causing interannual variations in genesis frequency. Specific factors that have more influence than others in different regions can be identified. For example, in El Niño years, relative humidity and vertical shear are important for the reduction in genesis seen in the Atlantic basin, and relative humidity and vorticity are important for the eastward shift in the mean genesis location in the western North Pacific.

To evaluate the optimum conditions for osteogenesis during limb lengthening and to study the changes in soft tissues undergoing elongation, a series of experiments were performed on the canine tibia. The experiments used the transfixion-wire, Ilizarov circular external skeletal fixator in configurations of differing stability of fixation in combination with a second variable, i.e., preservation of the periosteum, bone marrow, and medullary blood supply. Both increased fixator stability, and maximum preservation of the periosseous and intraosseous soft tissues enhanced bone formation during limb lengthening. To assess the role that the direction of the elongation vector plays in osteogenesis, canine tibiae were widened rather than lengthened in a second series of experiments using an Ilizarov apparatus modified for lateral distraction. The new bone formed parallel to the tension vector even when perpendicular to the bone's mechanical axis. As in longitudinal lengthening, damage to the bone marrow inhibits osteogenesis occurring by the influence of a lateral tension-stress vector. In a third series of experiments, half- and full-circumference cortical defects were created in canine tibiae to study the osteogenic potential of the marrow. New bone formed rapidly, even when the marrow was separated from the surrounding periosseous soft tissues by a sheet of polyvinyl chloride, attesting to the importance of marrow element preservation during osteotomy for limb lengthening.

Research Article| March 01, 2011 Ophiolite genesis and global tectonics: Geochemical and tectonic fingerprinting of ancient oceanic lithosphere Yildirim Dilek; Yildirim Dilek † 1Department of Geology, Shideler Hall, Miami University, Oxford, Ohio 45056, USA, and Faculty of Earth Sciences, China University of Geosciences at Wuhan, Wuhan 430074, Hubei Province, China †E-mail: dileky@muohio.edu. Search for other works by this author on: GSW Google Scholar Harald Furnes Harald Furnes 2Department of Earth Science & Centre for Geobiology, University of Bergen, Bergen 5007, Norway Search for other works by this author on: GSW Google Scholar Author and Article Information Yildirim Dilek † 1Department of Geology, Shideler Hall, Miami University, Oxford, Ohio 45056, USA, and Faculty of Earth Sciences, China University of Geosciences at Wuhan, Wuhan 430074, Hubei Province, China Harald Furnes 2Department of Earth Science & Centre for Geobiology, University of Bergen, Bergen 5007, Norway †E-mail: dileky@muohio.edu. Publisher: Geological Society of America Received: 15 Nov 2010 Revision Received: 14 Dec 2010 Accepted: 15 Dec 2010 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2011 Geological Society of America GSA Bulletin (2011) 123 (3-4): 387–411. https://doi.org/10.1130/B30446.1 Article history Received: 15 Nov 2010 Revision Received: 14 Dec 2010 Accepted: 15 Dec 2010 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Yildirim Dilek, Harald Furnes; Ophiolite genesis and global tectonics: Geochemical and tectonic fingerprinting of ancient oceanic lithosphere. GSA Bulletin 2011;; 123 (3-4): 387–411. doi: https://doi.org/10.1130/B30446.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Ophiolites, and discussions on their origin and significance in Earth's history, have been instrumental in the formulation, testing, and establishment of hypotheses and theories in earth sciences. The definition, tectonic origin, and emplacement mechanisms of ophiolites have been the subject of a dynamic and continually evolving concept since the nineteenth century. Here, we present a review of these ideas as well as a new classification of ophiolites, incorporating the diversity in their structural architecture and geochemical signatures that results from variations in petrological, geochemical, and tectonic processes during formation in different geodynamic settings. We define ophiolites as suites of temporally and spatially associated ultramafic to felsic rocks related to separate melting episodes and processes of magmatic differentiation in particular tectonic environments. Their geochemical characteristics, internal structure, and thickness vary with spreading rate, proximity to plumes or trenches, mantle temperature, mantle fertility, and the availability of fluids. Subduction-related ophiolites include suprasubduction-zone and volcanic-arc types, the evolution of which is governed by slab dehydration and accompanying metasomatism of the mantle, melting of the subducting sediments, and repeated episodes of partial melting of metasomatized peridotites. Subduction-unrelated ophiolites include continental-margin, mid-ocean-ridge (plume-proximal, plume-distal, and trench-distal), and plume-type (plume-proximal ridge and oceanic plateau) ophiolites that generally have mid-ocean-ridge basalt (MORB) compositions. Subduction-related lithosphere and ophiolites develop during the closure of ocean basins, whereas subduction-unrelated types evolve during rift drift and seafloor spreading. The peak times of ophiolite genesis and emplacement in Earth history coincided with collisional events leading to the construction of supercontinents, continental breakup, and plume-related supermagmatic events. Geochemical and tectonic fingerprinting of Phanerozoic ophiolites within the framework of this new ophiolite classification is an effective tool for identification of the geodynamic settings of oceanic crust formation in Earth history, and it can be extended into Precambrian greenstone belts in order to investigate the ways in which oceanic crust formed in the Archean. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Carbonatites - nomenclature, average chemical compositions and element distribution, A.R.Woolley & D.R.C.Kempe the spatial and temporal distribution of carbonatites, A.R.Woolley field relations of carbonatites, D.S.Barker extrusive carbonatites and their significance, J.Keller carbonatite magma - properties and processes, A.H.Treiman pyrochlore, apatite and amphibole - distinctive minerals in carbonatite, D.D.Hogarth nature of economic mineralization in carbonatites and related rocks, A.N.Mariano nature and structural relationships of carbonatites from Southwest and West Tanzania, P.van Straaten carbonatites in a continental margin environment - the Canadian Cordillera, J.Pell & T.Hoy Phalaborwa - a saga of magmatism, metasomatism and miscibility, S.C.Eriksson sodium carbonatite extrusions from Oldoinyo Lengai, Tanzania - implications for carbonatite complex genesis, J.B.Dawson neodymium and Sr isotope geochemistry of carbonatites, K.Bell & J.Blenkinsop stable isotope variations in carbonatites, P.Deines lead isotope relationships in carbonatites and alkalic complexes - an overview, S.T.Kwon et al the genesis of carbonatites by immiscibility, B.A.Kjarsgaard & D.L.Hamilton the behaviour of trace elements in the evolution of carbonatites, D.L.Hamilton et al diversification of carbonatite, M.J.Le Bas upper-mantle enrichment by kimberlitic or carbonatitic magmatism, A.P.Jones a model of mantle metasomatism by carbonated alkaline melts - trace-element and isotopic compositions of mantle source regions of carbonatite and other continental igneous rocks, J.K.Meen et al origin of carbonatites - evidence from phase equilibrium studies, P.J.Wyllie mantle metasomes and the kinship between carbonatites and kimberlites, S.E.Haggerty carbonatites, primary melts and mantle dynamics, D.H.Eggler the origin and evolution of carbonatite magmas, J.Gittins.

Carbonate minerals are stained over a set period of time with alizarin red-S and potassium ferricyanide only if they will react with dilute hydrochloric acid solution, with which the stain is prepared. The rates of solution of carbonates in the acid control the intensity of color development. For calcite, the rate of solution varies with the optic orientation of the section. The speed of carbonate solution is changed if the acid concentration is altered, but only at concentrations of about 0.1 N is the optic orientation of calcite differentiated by the stain. Etching reduces thin section thickness and clarifies rock texture. Staining with alizarin red-S differentiates carbonate minerals into two groups. Aragouite, calcite, witherlte t and cerussite, which dissolve rapidly in dilute hydrochloric acid, are stained, while dolomite, siderite, magnesite, and rhodochosite, which react much more slowly with the acid, remain unstained. The distribution of ferrous iron, as distinguished by staining with potassium ferricyanide, has proved to be highly significant in the genesis of cements. Ferrous iron can be introduced at any one stage in cementation, or repeatedly, forming zoned patterns. The paragenesis of zoned ferroan cements can be reconstructed after stain-ing. Solution of the more soluble original constituents can sometimes be dated in relation to cementation. Ferroan calcite can be secondary inorigin and is usually associated with replacement minerals.

Two major functions of the mammalian ovary are the production of germ cells (oocytes), which allow continuation of the species, and the generation of bioactive molecules, primarily steroids (mainly estrogens and progestins) and peptide growth factors, which are critical for ovarian function, regulation of the hypothalamic-pituitary-ovarian axis, and development of secondary sex characteristics. The female germline is created during embryogenesis when the precursors of primordial germ cells differentiate from somatic lineages of the embryo and take a unique route to reach the urogenital ridge. This undifferentiated gonad will differentiate along a female pathway, and the newly formed oocytes will proliferate and subsequently enter meiosis. At this point, the oocyte has two alternative fates: die, a common destiny of millions of oocytes, or be fertilized, a fate of at most approximately 100 oocytes, depending on the species. At every step from germline development and ovary formation to oogenesis and ovarian development and differentiation, there are coordinated interactions of hundreds of proteins and small RNAs. These studies have helped reproductive biologists to understand not only the normal functioning of the ovary but also the pathophysiology and genetics of diseases such as infertility and ovarian cancer. Over the last two decades, parallel progress has been made in the assisted reproductive technology clinic including better hormonal preparations, prenatal genetic testing, and optimal oocyte and embryo analysis and cryopreservation. Clearly, we have learned much about the mammalian ovary and manipulating its most important cargo, the oocyte, since the birth of Louise Brown over 30 yr ago.

Part I. The Building Blocks of Soils: 1. Introduction 2. Basic concepts: soil morphology 3. Basic concepts: soil horizonation... the alphabet of soils 4. Basic concepts: soil mineralogy 5. Basic concepts: soil chemistry 6. Basic concepts: soil physics 7. Basic concepts: soil organisms 8. Soil classification and mapping 9. Weathering Part II. Soil Genesis: From Parent Material to Soil: 10. Soil parent materials 11. Pedoturbation 12. Models and concepts of soil formation 13. Soil genesis and profile differentiation Part III. Soil Geomorphology: 14. Soil geomorphology and hydrology 15. Soil development and surface exposure dating 16. Soils, paleosols, and paleoenvironmental reconstruction 17. Conclusions.

In The Genesis of Animal Play, Gordon Burghardt examines the origins and evolution of play in humans and animals. He asks what play might mean in our understanding of evolution, the brain, behavioral organization, and psychology. Is play essential to development? Is it the driving force behind human and animal behavior? What is the proper place for the study of play in the cognitive, behavioral, and biological sciences? The engaging nature of play—who does not enjoy watching a kitten attack a ball of yarn?—has made it difficult to study. Some scholars have called play undefinable, nonexistent, or a mystery outside the realm of scientific analysis. Using the comparative perspectives of ethology and psychology, The Genesis of Animal Play goes further than other studies in reviewing the evidence of play throughout the animal kingdom, from human babies to animals not usually considered playful. Burghardt finds that although playfulness may have been essential to the origin of much that we consider distinctive in human (and mammalian) behavior, it only develops through a specific set of interactions among developmental, evolutionary, ecological, and physiological processes. Furthermore, play is not always beneficial or adaptive. Part I offers a detailed discussion of play in placental mammals (including children) and develops an integrative framework called surplus resource theory. The most fascinating and most controversial sections of the book, perhaps, are in the seven chapters in part II in which Burghardt presents evidence of playfulness in such unexpected groups of animals as kangaroos, birds, lizards, and "Fish That Leap, Juggle, and Tease." Burghardt concludes by considering the implications of the diversity of play for future research, and suggests that understanding the origin and development of play can shape our view of society and its accomplishments through history. The open access edition of this book was made possible by generous funding from Arcadia – a charitable fund of Lisbet Rausing and Peter Baldwin.

A versatile, platform independent and easy to use Java suite for large-scale gene expression analysis was developed. Genesis integrates various tools for microarray data analysis such as filters, normalization and visualization tools, distance measures as well as common clustering algorithms including hierarchical clustering, self-organizing maps, k-means, principal component analysis, and support vector machines. The results of the clustering are transparent across all implemented methods and enable the analysis of the outcome of different algorithms and parameters. Additionally, mapping of gene expression data onto chromosomal sequences was implemented to enhance promoter analysis and investigation of transcriptional control mechanisms.

Hypertension promotes atherosclerosis and is a major source of morbidity and mortality. We show that mice lacking T and B cells (RAG-1-/- mice) have blunted hypertension and do not develop abnormalities of vascular function during angiotensin II infusion or desoxycorticosterone acetate (DOCA)-salt. Adoptive transfer of T, but not B, cells restored these abnormalities. Angiotensin II is known to stimulate reactive oxygen species production via the nicotinamide adenosine dinucleotide phosphate (NADPH) oxidase in several cells, including some immune cells. Accordingly, adoptive transfer of T cells lacking the angiotensin type I receptor or a functional NADPH oxidase resulted in blunted angiotensin II-dependent hypertension and decreased aortic superoxide production. Angiotensin II increased T cell markers of activation and tissue homing in wild-type, but not NADPH oxidase-deficient, mice. Angiotensin II markedly increased T cells in the perivascular adipose tissue (periadventitial fat) and, to a lesser extent the adventitia. These cells expressed high levels of CC chemokine receptor 5 and were commonly double negative (CD3+CD4-CD8-). This infiltration was associated with an increase in intercellular adhesion molecule-1 and RANTES in the aorta. Hypertension also increased T lymphocyte production of tumor necrosis factor (TNF) alpha, and treatment with the TNFalpha antagonist etanercept prevented the hypertension and increase in vascular superoxide caused by angiotensin II. These studies identify a previously undefined role for T cells in the genesis of hypertension and support a role of inflammation in the basis of this prevalent disease. T cells might represent a novel therapeutic target for the treatment of high blood pressure.

The newly developed GSAS-II software is a general purpose package for data reduction, structure solution and structure refinement that can be used with both single-crystal and powder diffraction data from both neutron and X-ray sources, including laboratory and synchrotron sources, collected on both two- and one-dimensional detectors. It is intended that GSAS-II will eventually replace both the GSAS and the EXPGUI packages, as well as many other utilities. GSAS-II is open source and is written largely in object-oriented Python but offers speeds comparable to compiled code because of its reliance on the Python NumPy and SciPy packages for computation. It runs on all common computer platforms and offers highly integrated graphics, both for a user interface and for interpretation of parameters. The package can be applied to all stages of crystallographic analysis for constant-wavelength X-ray and neutron data. Plans for considerable additional development are discussed.

From the first issue in 1905 onward, Economic Geology has been the main publication for those who study mineral deposits; indeed, it is now difficult to imagine economic geology without Economic Geology. It is interesting to ask, therefore, Who were the farsighted people who founded the journal, and Why did they think a specialized publication devoted to mineral deposits was needed?Let us first address the question, Who were the founders? They were the 12 men who collectivelydecided a new publication was needed, who then planned the financial structure to support the venture, and who served as the original editorial group. All were employed by, or associated with, the U.S. Geological Survey. Josiah Edward Spurr suggested the need for a journal sometime in November or December 1904. After informal discussions, nine of the founders met in the office of Waldemar Lindgren in the headquarters of the U.S. Geological Survey in Washington, D.C., on May 16, 1905, and founded the Economic Geology Publishing Company. The sole purpose of the company was the publication of a journal ‘...devoted primarily to the broad application of geologicprinciples to mineral deposits of economic value, and to the scientific description of such deposits, and particularly to the chemical, physical, and structural problems bearing on their genesis.’ Initial financing for the new company was raised by the sale of 80 shares at a cost of $25 per share.Eight of the men at the founding meeting formed the first board of directors; Spurr was president, Frederick L. Ransome, secretary, and George O. Smith, treasurer. Other members were Arthur H. Brooks, Marius R. Campbell, Walter H. Weed, Waldemar Lindgren, and a young academic from Lehigh University in Pennsylvania, John D. Irving. Theninth man at the meeting was H. Foster Bain. Irving was appointed editor. Lindgren, Ransome, and Campbell from the U.S. Geological Survey, together with three academics, James F. Kemp of Columbia University, Heinrich Ries ofCornell University, and Charles K. Leith of the University of Wisconsin, were appointed associate editors. The initial board members, the editor, and associate editors are the people we now recognize as the founders of Economic Geology. Two others, Frank D. Adams, of McGill University in Canada, and John. W. Gregory, of Glasgow University in Scotland, were subsequently added as associate editors, and a third person, W. S. Bayley of the University of Illinois, was appointed as business editor, but

Partial table of contents: Organic Matter in Soils: Pools, Distribution, Transformations, and Function. Extraction, Fractionation, and General Chemical Composition of Soil Organic Matter. Organic Forms of Soil Nitrogen. Native Fixed Ammonium and Chemical Reactions of Organic Matter with Ammonia and Nitrite. Organic Phosphorus and Sulfur Compounds. Soil Carbohydrates. Soil Lipids. Biochemistry of the Formation of Humic Substances. Reactive Functional Groups. Structural Components of Humic and Fulvic Acids as Revealed by Degradation Methods. Characterization of Soil Organic Matter by NMR Spectroscopy and Analytical Pyrolysis. Structural Basis of Humic Substances. Spectroscopic Approaches. Colloidal Properties of Humic Substances. Electrochemical and Ion-Exchange Properties of Humic Substances. Organic Matter Reactions Involving Pesticides in Soil. Index.

In this paper I demonstrate the way in which people's beliefs about the aetiology of their particular affliction (arthritis) need to be understood as part of a more comprehensive imaginative enterprise which I refer to as narrative reconstruction. The intrinsically teleological form of this enterprise means that identified 'causes' represent only putative efficient connexions between the disease and antecedent factors but also narrative reference points between the individual and society in an unfolding process which has become profoundly disrupted. Through the presentation of case material taken from lengthy interviews I illustrate the way in which my question to the subjects about the cause of their disease: 'Why do you think you got arthritis?' was translated by them into a narrative reconstruction of their changing relationship to the world in which they live and the genesis of illness within it.

An extensive body of knowledge exists on network outcomes and on how network structures may contribute to the creation of outcomes at different levels of analysis, but less attention has been paid to understanding how and why organizational networks emerge, evolve, and change. Improved understanding of network dynamics is important for several reasons, perhaps the most critical being that the understanding of network outcomes is only partial without an appreciation of the genesis of the network structures that resulted in such outcomes. To provide a context for the papers in this special issue, and with the broader goal of furthering network dynamics research, we present a framework that begins by discussing the meaning and role of network dynamics and goes on to identify the drivers and key dimensions of network change as well as the role of time in this process. We conclude with theoretical and methodological issues that researchers need to address in this domain.

Complex hierarchic syntax is a hallmark of human language. The highest level of syntactic complexity, recursive-embedded clauses, has been singled out by some for a special status as the evolutionary apex of the uniquely - human language faculty - evolutionary yet mysteriously immune to Darwinian adaptive selection. Prof. Givón's book treats syntactic complexity as an integral part of the evolutionary rise of human communication. The book first describes grammar as an adaptive instrument of communication, assembled upon the pre-existing platform of pre-linguistic object- and-event cognition and mental representation. It then surveys the two grand developmental trends of human language: diachrony , the communal enterprise directly responsible for fashioning synchronic morpho-syntax and cross-language diversity; and ontogeny , the individual endeavor directly responsible for acquiring the competent use of grammar. The genesis of syntactic complexity along these two developmental trends is compared with second language acquisition, pre-grammatical pidgin and pre-human communication. The evolutionary relevance of language diachrony, language ontogeny and pidginization is argued for on general bio-evolutionary grounds: It is the organism's adaptive on-line behavior - invention, learning and skill acquisition - that is the common thread running through all three developmental trends. The neuro-cognitive circuits that underlie language, and their evolutionary underpinnings, are described and assessed. Recursive embedding turns out to be not an adaptive target on its own, but the by-product of two distinct adaptive moves: (i) the recruitment of conjoined clauses as modal operators on, or referential specifiers of, other clauses; and (ii) the subsequent condensation of paratactic into syntactic structures.

A putative tumor suppressor locus on the short arm of human chromosome 9 has been localized to a region of less than 40 kilobases by means of homozygous deletions in melanoma cell lines. This region contained a gene, Multiple Tumor Suppressor 1 (MTS1), that encodes a previously identified inhibitor (p16) of cyclin-dependent kinase 4. MTS1 was homozygously deleted at high frequency in cell lines derived from tumors of lung, breast, brain, bone, skin, bladder, kidney, ovary, and lymphocyte. Melanoma cell lines that carried at least one copy of MTS1 frequently carried nonsense, missense, or frameshift mutations in the gene. These findings suggest that MTS1 mutations are involved in tumor formation in a wide range of tissues.

Research on mudrock attributes has increased dramatically since shale-gas systems have become commercial hydrocarbon production targets. One of the most significant research questions now being asked focuses on the nature of the pore system in these mudrocks. Our work on siliceous mudstones from the Mississippian Barnett Shale of the Fort Worth Basin, Texas, shows that the pores in these rocks are dominantly nanometer in scale (nanopores). We used scanning electron microscopy to characterize Barnett pores from a number of cores and have imaged pores as small as 5 nm. Key to our success in imaging these nanopores is the use of Ar-ion-beam milling; this methodology provides flat surfaces that lack topography related to differential hardness and are fundamental for high-magnification imaging. Nanopores are observed in three main modes of occurrence. Most pores are found in grains of organic matter as intraparticle pores; many of these grains contain hundreds of pores. Intraparticle organic nanopores most commonly have irregular, bubblelike, elliptical cross sections and range between 5 and 750 nm with the median nanopore size for all grains being approximately 100 nm. Internal porosities of up to 20.2% have been measured for whole grains of organic matter based on point-count data from scanning electron microscopy analysis. These nanopores in the organic matter are the predominant pore type in the Barnett mudstones and they are related to thermal maturation. Nanopores are also found in bedding-parallel, wispy, organic-rich laminae as intraparticle pores in organic grains and as interparticle pores between organic matter, but this mode is not common. Although less abundant, nanopores are also locally present in fine-grained matrix areas unassociated with organic matter and as nano- to microintercrystalline pores in pyrite framboids. Intraparticle organic nanopores and pyrite-framboid intercrystalline pores contribute to gas storage in Barnett mudstones. We postulate that permeability pathways within the Barnett mudstones are along bedding-parallel layers of organic matter or a mesh network of organic matter flakes because this material contains the most pores.

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