944 resultados para 020110 Stellar Astronomy and Planetary Systems
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Using the once and thrice energy-weighted moments of the random-phase-approximation strength function, we have derived compact expressions for the average energy of surface collective oscillations of clusters and spheres of metal atoms. The L=0 volume mode has also been studied. We have carried out quantal and semiclassical calculations for Na and Ag systems in the spherical-jellium approximation. We present a rather thorough discussion of surface diffuseness and quantal size effects on the resonance energies.
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This paper reports on the purpose, design, methodology and target audience of E-learning courses in forensic interpretation offered by the authors since 2010, including practical experiences made throughout the implementation period of this project. This initiative was motivated by the fact that reporting results of forensic examinations in a logically correct and scientifically rigorous way is a daily challenge for any forensic practitioner. Indeed, interpretation of raw data and communication of findings in both written and oral statements are topics where knowledge and applied skills are needed. Although most forensic scientists hold educational records in traditional sciences, only few actually followed full courses that focussed on interpretation issues. Such courses should include foundational principles and methodology - including elements of forensic statistics - for the evaluation of forensic data in a way that is tailored to meet the needs of the criminal justice system. In order to help bridge this gap, the authors' initiative seeks to offer educational opportunities that allow practitioners to acquire knowledge and competence in the current approaches to the evaluation and interpretation of forensic findings. These cover, among other aspects, probabilistic reasoning (including Bayesian networks and other methods of forensic statistics, tools and software), case pre-assessment, skills in the oral and written communication of uncertainty, and the development of independence and self-confidence to solve practical inference problems. E-learning was chosen as a general format because it helps to form a trans-institutional online-community of practitioners from varying forensic disciplines and workfield experience such as reporting officers, (chief) scientists, forensic coordinators, but also lawyers who all can interact directly from their personal workplaces without consideration of distances, travel expenses or time schedules. In the authors' experience, the proposed learning initiative supports participants in developing their expertise and skills in forensic interpretation, but also offers an opportunity for the associated institutions and the forensic community to reinforce the development of a harmonized view with regard to interpretation across forensic disciplines, laboratories and judicial systems.
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In a no-tillage system, cover crops must be used that combine shoot dry matter production and nutrient recycling. The aim of this study was to evaluate shoot dry matter production, decomposition rate and macronutrient and silicon release from pigeonpea and pearl millet in monoculture and intercropping systems. A randomized block design was used with a 3 x 6 factorial arrangement, with four replications. The first factor consisted of three cover crops (pigeonpea, pearl millet and intercropping of these cover crops) and the second consisted of six sampling times [0, 18, 32, 46, 74 and 91 days after desiccation (DAD)]. Pearl millet produced greater amounts of shoot dry matter and content of N, P, K, Ca, Mg, S, C and Si and had a higher decomposition rate and macronutrient and Si release than the other cover crops. The rates of decomposition and daily nutrient release from shoot dry matter were highest in the first period of evaluation (0-18 DAD). Over time, the C/N, C/P and C/S ratios increased, while C/Si and the decomposition rate decreased. Potassium was the nutrient most quickly released to the soil, especially from pearl millet residue. Silicon had the lowest release rate, with 62, 82 and 74 % of the total content in the shoot dry matter remaining in the last evaluation of pearl millet, pigeonpea and in the intercrop system, respectively. The shoot dry matter from the intercrop system had a different decomposition rate than that from the pearl millet monoculture and pigeonpea. Plants with greater shoot dry matter production and lower C/Si ratio are more effective in a no-tillage system for providing a more complete and persistent soil cover.
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Soil management, in terms of tillage and cropping systems, strongly influences the biological properties of soil involved in the suppression of plant diseases. Fungistasis mediated by soil microbiota is an important component of disease-suppressive soils. We evaluated the influence of different management systems on fungistasis against Fusarium graminearum, the relationship of fungistasis to the bacterial profile of the soil, and the possible mechanisms involved in this process. Samples were taken from a long-term experiment set up in a Paleudult soil under conventional tillage or no-tillage management and three cropping systems: black oat (Avena strigose L.) + vetch (Vicia sativa L.)/maize (Zea mays L.) + cowpea (Vigna sinensis L.), black oat/maize, and vetch/maize. Soil fungistasis was evaluated in terms of reduction of radial growth of F. graminearum, and bacterial diversity was assessed using ribosomal intergenic spacer analysis (RISA). A total of 120 bacterial isolates were obtained and evaluated for antibiosis, and production of volatile compounds and siderophores. No-tillage soil samples showed the highest level of F. graminearum fungistasis by sharply reducing the development of this pathogen. Of the cropping systems tested, the vetch + black oat/maize + cowpea system showed the highest fungistasis and the oat/maize system showed the lowest. The management system also affected the genetic profile of the bacteria isolated, with the systems from fungistatic soils showing greater similarity. Although there was no clear relationship between soil management and the characteristics of the bacterial isolates, we may conclude that antibiosis and the production of siderophores were the main mechanisms accounting for fungistasis.
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Delamination and foundering of the lower continental crust (LCC) into the mantle is part of the crust-forming mechanism. However, knowledge of the composition and mineralogy of the preserved or delaminated LCC over geological timescales remains scarce. We provide a synopsis of recent research within the Kohistan arc (Pakistan) and demonstrate that hydrous and less hydrous liquid lines of descent related to flux assisted and decompression mantle melting, respectively, produce compositionally different lower crustal rocks. The argument refers to two lower crustal sections exposed in Kohistan, the older Southern Plutonic Complex (SPC) and the younger Chilas Complex. The SPC typifies a hydrous, high-pressure fractionation sequence of olivine-pyroxenes-garnet-Fe/Ti-oxide-amphibole-plagioclase. The Chilas Complex illustrates a less hydrous fractionation sequence of olivine-clinopyroxene-orthopyroxene-plagioclase-amphibole. Despite the similarity of the Chilas Complex rocks to proposed lower crust compositions, the less hydrous fractionation results in unrealistically small volumes of silica-rich rocks, precluding the Chilas Complex gabbros to represent the magmatic complement to the upper crust. The composition of the SPC lower crust differs markedly from bulk lower crust estimates, but is complementary to silica-rich rocks exposed along this section and in the Kohistan batholith. These observations inspire a composite model for the formation of continental crust (CC) where the negatively buoyant delaminated and the buoyant preserved lower continental crusts (LCC) differ in genesis, mineralogy, and composition. We propose that the upper, non-sedimentary subsequent removal of the complementary, negatively buoyant garnet-pyroxene-amphibole-plagioclase-rich cumulates. In contrast, the LCC, which is buoyant and preserved over geological timescales, is formed by less hydrous parental mantle melts. We suggest that the bulk continental crust composition is related to mixing of these petrologically not directly related end members. Published by Elsevier B.V.
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The discipline of Enterprise Architecture Management (EAM) deals with the alignment of business and information systems architectures. While EAM has long been regarded as a discipline for IT managers this book takes a different stance: It explains how top executives can use EAM for leveraging their strategic planning and controlling processes and how EAM can contribute to sustainable competitive advantage. Based on the analysis of best practices from eight leading European companies from various industries the book presents crucial elements of successful EAM. It outlines what executives need to do in terms of governance, processes, methodologies and culture in order to bring their management to the next level. Beyond this, the book points how EAM might develop in the next decade allowing today's managers to prepare for the future of architecture management.
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Schizotypy, defined in terms of commonly occurring personality traits related to the schizophrenia spectrum, has been an important construct for understanding the neurodevelopment and stress-diathesis of schizophrenia. However, as schizotypy nears its sixth decade of application, it is important to acknowledge its impressively rich literature accumulating outside of schizophrenia research. In this article, we make the case that schizotypy has considerable potential as a conceptual framework for understanding individual differences in affective and social functions beyond those directly involved in schizophrenia spectrum pathology. This case is predicated on (a) a burgeoning literature noting anomalies in a wide range of social functioning, affiliative, positive and negative emotional, expressive, and social cognitive systems, (b) practical and methodological features associated with schizotypy research that help facilitate empirical investigation, and (c) close ties to theoretical constructs of central importance to affective and social science (eg, stress diathesis, neural compensation). We highlight recent schizotypy research, ie providing insight into the nature of affective and social systems more generally. This includes current efforts to clarify the neurodevelopmental, neurobiological, and psychological underpinnings of affiliative drives, hedonic capacity, social cognition, and stress responsivity systems. Additionally, we discuss neural compensatory and resilience factors that may mitigate the expression of stress-diathesis and functional outcome, and highlight schizotypy's potential role for understanding cultural determinants of social and affective functions.
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The generation of a high productivity cell line is a critical step in the production of a therapeutic protein. Many innovative engineering strategies have been devised in order to maximize the expression rate of production cells for increased process efficiency. Less effort has focused on improvements to the cell line generation process, which is typically long and laborious when using mammalian cells. Based on unexpected findings when generating stable CHO cell lines expressing human IL-17F, we studied the benefit of expressing this protein during the establishment of production cell lines. We demonstrate that IL-17F expression enhances the rate of selection and overall number of selected cell lines as well as their transgene expression levels. We also show that this benefit is observed with different parental CHO cell lines and selection systems. Furthermore, IL-17F expression improves the efficiency of cell line subcloning processes. IL-17F can therefore be exploited in a standard manufacturing process to obtain higher productivity clones in a reduced time frame.
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To constrain the age of strike-slip shear, related granitic magmatism, and cooling along the Insubric line, 29 size fractions of monazite and xenotime were dated by the U-Pb method, and a series of 25 Rb-Sr and Ar-40/Ar-39 ages were measured on different size fractions of muscovite and biotite. The three pegmatitic intrusions analyzed truncate high-grade metamorphic mylonite gneisses of the Simplon shear zone, a major Alpine structure produced in association with dextral strike-slip movements along the southern edge of the European plate, after collision with its Adriatic indenter. Pegmatites and aplites were produced between 29 and 25 Ma in direct relation to right-lateral shear along the Insubric line, by melting of continental crust having Sr-87/Sr-86 between 0.7199 and 0.7244 at the time of melting. High-temperature dextral strike-slip shear was active at 29.2 +/- 0.2 (2 sigma) Ma, and it terminated before 26.4 +/- 0.1 Ma. During dike injection, temperatures in the country rocks of the Isorno-Orselina and Monte Rosa structural units did not exceed approximate to 500 degrees C, leading to fast initial cooling, followed by slower cooling to approximate to 350 degrees C within several million years. In one case, initial cooling to approximate to 500 degrees C was significantly delayed by about 4 m.y., with final cooling to approximate to 300 degrees C at 20-19 Ma in all units. For the period between 29 and 19 Ma, cooling of the three sample localities was non-uniform in space and time, with significant variations on the kilometre scale. These differences are most likely due to strongly varying heat flow, and/or heterogeneous distribution of unroofing rates within the continuously deforming Insubric line. If entirely ascribed to differences in unroofing, corresponding rates would vary between 0.5 and 2.5 mm/y, for a thermal gradient of 30 degrees/km.
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The Permo-Triassic crisis was a major turning point in geological history. Following the end-Guadalupian extinction phase, the Palaeozoic biota underwent a steady decline through the Lopingian (Late Permian), resulting in their decimation at the level that is adopted as the Permian-Triassic boundary (PTB). This trend coincided with the greatest Phanerozoic regression. The extinction at the end of the Guadalupian and that marking the end of the Permian are therefore related. The subsequent recovery of the biota occupied the whole of the Early Triassic. Several phases of perturbations in [delta]13Ccarb occurred through a similar period, from the late Wuchiapingian to the end of the Early Triassic. Therefore, the Permian-Triassic crisis was protracted, and spanned Late Permian and Early Triassic time. The extinction associated with the PTB occurred in two episodes, the main act with a prelude and the epilogue. The prelude commenced prior to beds 25 and 26 at Meishan and coincided with the end-Permian regression. The main act itself happened in beds 25 and 26 at Meishan. The epilogue occurred in the late Griesbachian and coincided with the second volcanogenic layer (bed 28) at Meishan. The temporal distribution of these episodes constrains the interpretation of mechanisms responsible for the greatest Phanerozoic mass extinction, particularly the significance of a postulated bolide impact that to our view may have occurred about 50,000[no-break space]Myr after the prelude. The prolonged and multi-phase nature of the Permo-Triassic crisis favours the mechanisms of the Earth's intrinsic evolution rather than extraterrestrial catastrophe. The most significant regression in the Phanerozoic, the palaeomagnetic disturbance of the Permo-Triassic Mixed Superchron, widespread extensive volcanism, and other events, may all be related, through deep-seated processes that occurred during the integration of Pangea. These combined processes could be responsible for the profound changes in marine, terrestrial and atmospheric environments that resulted in the end-Permian mass extinction. Bolide impact is possible but is neither an adequate nor a necessary explanation for these changes.
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OBJECTIVE: To determine if the results of resin-dentin microtensile bond strength (µTBS) is correlated with the outcome parameters of clinical studies on non-retentive Class V restorations. METHODS: Resin-dentin µTBS data were obtained from one test center; the in vitro tests were all performed by the same operator. The µTBS testing was performed 8h after bonding and after 6 months of storing the specimens in water. Pre-test failures (PTFs) of specimens were included in the analysis, attributing them a value of 1MPa. Prospective clinical studies on cervical restorations (Class V) with an observation period of at least 18 months were searched in the literature. The clinical outcome variables were retention loss, marginal discoloration and marginal integrity. Furthermore, an index was formulated to be better able to compare the laboratory and clinical results. Estimates of adhesive effects in a linear mixed model were used to summarize the clinical performance of each adhesive between 12 and 36 months. Spearman correlations between these clinical performances and the µTBS values were calculated subsequently. RESULTS: Thirty-six clinical studies with 15 adhesive/restorative systems for which µTBS data were also available were included in the statistical analysis. In general 3-step and 2-step etch-and-rinse systems showed higher bond strength values than the 2-step/3-step self-etching systems, which, however, produced higher values than the 1-step self-etching and the resin modified glass ionomer systems. Prolonged water storage of specimens resulted in a significant decrease of the mean bond strength values in 5 adhesive systems (Wilcoxon, p<0.05). There was a significant correlation between µTBS values both after 8h and 6 months of storage and marginal discoloration (r=0.54 and r=0.67, respectively). However, the same correlation was not found between µTBS values and the retention rate, clinical index or marginal integrity. SIGNIFICANCE: As µTBS data of adhesive systems, especially after water storage for 6 months, showed a good correlation with marginal discoloration in short-term clinical Class V restorations, longitudinal clinical trials should explore whether early marginal staining is predictive for future retention loss in non-carious cervical restorations.
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A review of the Iowa Department of Transportation's field data collection and reporting system has been performed. Included were several systems used by the Office of Construction and Local Jurisdictions. The entire field data collection and reporting systems for asphalt cement concrete (ACC) paving, portland cement concrete (PCC) paving, and PCC structures were streamlined and computerized. The field procedures for materials acceptance were also reviewed. Best practices were identified and a method was developed to prioritize materials so transportation agencies could focus their efforts on high priority materials. Iowa State University researchers facilitated a discussion about Equal Employment Opportunity (EEO) and Affirmative Action (AA) procedures between the Office of Construction field staff and the Office of Contracts. A set of alternative procedures was developed. Later the Office of Contracts considered these alternatives as they developed new procedures that are currently being implemented. The job close-out package was reviewed and two unnecessary procedures were eliminated. Numerous other procedures were reviewed and flowcharted. Several changes have been recommended that will increase efficiency and allow staff time to be devoted to higher priority activities. It is estimated the improvements in ACC paving, PCC paving and structural concrete will by similar to three full time equivalent (FTE) positions to field construction, field materials and Office of Materials. Elimination of EEO interviews will be equivalent to one FTE position. It is estimated that other miscellaneous changes will be equivalent to at least one other FTE person. This is a total five FTEs. These are conservative estimates based on savings that are easily quantified. It is likely that total positive effect is greater when items that are difficult to quantify are considered.
Space Competition and Time Delays in Human Range Expansions. Application to the Neolithic Transition
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Space competition effects are well-known in many microbiological and ecological systems. Here we analyze such an effectin human populations. The Neolithic transition (change from foraging to farming) was mainly the outcome of a demographic process that spread gradually throughout Europe from the Near East. In Northern Europe, archaeological data show a slowdown on the Neolithic rate of spread that can be related to a high indigenous (Mesolithic) population density hindering the advance as a result of the space competition between the two populations. We measure this slowdown from a database of 902 Early Neolithic sites and develop a time-delayed reaction-diffusion model with space competition between Neolithic and Mesolithic populations, to predict the observed speeds. The comparison of the predicted speed with the observations and with a previous non-delayed model show that both effects, the time delay effect due to the generation lag and the space competition between populations, are crucial in order to understand the observations