15,856 research outputs found

    Quantitative evaluation of multiband photographic techniques Final report

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    Quantitative evaluation of multiband photographic techniques using combination of black and white and color photo

    Agricultural interpretation technique development

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    There are no author-identified significant results in this report

    Evaporites and the salinity of the ocean during the Phanerozoic: Implications for climate, ocean circulation and life

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    A compilation of data on volumes and masses of evaporite deposits is used as the basis for reconstruction of the salinity of the ocean in the past. Chloride is tracked as the only ion essentially restricted to the ocean, and past salinities are calculated from reconstructed chlorine content of the ocean. Models for ocean salinity through the Phanerozoic are developed using maximal and minimal estimates of the volumes of existing evaporite deposits, and using constant and declining volumes of ocean water through the Phanerozoic. We conclude that there have been significant changes in the mean salinity of the ocean accompanying a general decline throughout the Phanerozoic. The greatest changes are related to major extractions of salt into the young ocean basins which developed during the Mesozoic as Pangaea broke apart. Unfortunately, the sizes of these salt deposits are also the least well known. The last major extractions of salt from the ocean occurred during the Miocene, shortly after the large scale extraction of water from the ocean to form the ice cap of Antarctica. However, these two modifications of the masses of H2O and salt in the ocean followed in sequence and did not cancel each other out. Accordingly, salinities during the Early Miocene were between 37‰ and 39‰. The Mesozoic was a time of generally declining salinity associated with the deep sea salt extractions of the North Atlantic and Gulf of Mexico (Middle to Late Jurassic) and South Atlantic (Early Cretaceous). The earliest of the major extractions of the Phanerozoic occurred during the Permian. There were few large extractions of salt during the earlier Palaeozoic. The models suggest that this was a time of relatively stable but slowly increasing salinities ranging through the upper 40‰'s into the lower 50‰'s. Higher salinities for the world ocean have profound consequences for the thermohaline circulation of the ocean in the past. In the modern ocean, with an average salinity of about 34.7‰, the density of water is only very slightly affected by cooling as it approaches the freezing point. Consequently, salinization through sea-ice formation or evaporation is usually required to make water dense enough to sink into the ocean interior. At salinities above about 40‰ water continues to become more dense as it approaches the freezing point, and salinization is not required. The energy-consuming phase changes involved in sea-ice formation and evaporation would not be required for vertical circulation in the ocean. The hypothesized major declines in salinity correspond closely to the evolution of both planktonic foraminifera and calcareous nannoplankton. Both groups were restricted to shelf regions in the Jurassic and early Cretaceous, but spread into the open ocean in the mid-Cretaceous. Their availability to inhabit the open ocean may be directly related to the decline in salinity. The Permian extraction may have created stress for marine organisms and may have been a factor contributing to the end-Permian extinction. The modeling also suggests that there was a major salinity decline from the Late Precambrian to the Cambrian, and it is tempting to speculate that this may have been a factor in the Cambrian explosion of life

    Development of techniques for producing static strata maps and development of photointerpretive methods based on multitemporal LANDSAT data

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    Progress in the evaluation of the static stratification procedure and the development of alternative photointerpretive techniques to the present LACIE procedure for the identification of training fields is reported. Statistically significant signature controlling variables were defined for use in refining the stratification procedure. A subset of the 1973-74 Kansas LACIE segments for wheat was analyzed

    Development of techniques for producing static strata maps and development of photointerpretation methods based on multitemporal LANDSAT data

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    The progress of research conducted in support of the Large Area Crop Inventory Experiment (LACIE) is documented. Specific tasks include (1) evaluation of the static stratification procedure and modification of that procedure if warranted, and (2) the development of alternative photointerpretative techniques to the present LACIE procedures for the identification and selection of training fields (areas)

    A General Solution for Linear Decision Rules: An Optimal Dynamic Strategy Applicable Under Uncertainty

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    Linear decision rules for controlling complex systems are often obtained by matrix inversion, but transform methods offer an alternative approach that yields insights into the structure of the decision problem of maximizing expected payoffs under constraints

    Implications of the Dirac CP phase upon parametric resonance for sub-GeV neutrinos

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    We perform an analytic and numerical study of parametric resonance in a three-neutrino framework for sub-GeV neutrinos which travel through a periodic density profile. Commensurate with the initial level of approximation, we develop a parametric resonance condition similar to the exact condition for two-neutrino systems. For a castle-wall density profile, the νe→νμ oscillation probability is enhanced significantly and bounded by cos2θ23. The CP phase δ enters into the oscillation probability as a phase shift. For several cases, we examine the interplay between the characteristics of the castle-wall profile and the CP phase and determine which profiles maximize the separation between oscillations with δ=0,±π2,π. We also consider neutrinos which travel along a chord through the Earth, passing from the mantle to core and back to mantle again. Significant enhancement of the oscillation probability is seen even in the case in which the neutrino energy is far from the MSW resonant energies. At 500 GeV, the difference between oscillation probabilities with δ=0 and δ=π2 is maximized

    Morphogenetic Theory and the Constructivist Institutionalist Challenge

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    This article engages with two meta-theoretical approaches to social analysis, ‘morphogenetic theory’ and ‘constructivist institutionalism’, and specifically explores how the former fares under the critical scrutiny of the latter. The key proponent of constructivist institutionalism, Colin Hay, has offered two detailed critiques of morphogenesis that criticise its position on the foundational sociological issues of structure-agency and material-ideational. Although Hay’s critiques are largely rejected in an overall defence of the morphogenetic approach, the process of engagement is seen to be particularly useful for morphogenetic theory because it allows a number of important clarifications to be made and it also opens up space for theoretical development. In the course of this debate, accessible introductions are given to both theories, and the similarities and differences between them are outlined, providing clarity to both. Therefore, although this article ultimately operates as a defence of morphogenetic theory, especially in the form proposed by Margaret Archer and Douglas Porpora, it finds a great deal of fruitful discussion in the constructivist institutionalist challenge

    A General Solution for Linear Decision Rules: An Optimal Dynamic Strategy Applicable Under Uncertainty

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    Linear decision rules for controlling complex systems are often obtained by matrix inversion, but transform methods offer an alternative approach that yields insights into the structure of the decision problem of maximizing expected payoffs under constraints

    Incontinence-specific quality of life measures used in trials of treatments for female urinary incontinence: a systematic review.

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    This systematic review examined the use of incontinence-specific QOL measures in clinical trials of female incontinence treatments, and systematically evaluated their quality using a standard checklist. Of 61 trials included in the review, 58 (95.1%) used an incontinence-specific QOL measure. The most commonly used were IIQ (19 papers), I-QoL (12 papers) and UDI (9 papers). Eleven papers (18.0%) used measures which were not referenced or were developed specifically for the study. The eight QOL measures identified had good clinical face validity and measurement properties. We advise researchers to evaluate carefully the needs of their specific study, and select the QOL measure that is most appropriate in terms of validity, utility and relevance, and discourage the development of new measures. Until better evidence is available on the validity and comparability of measures, we recommend that researchers consider using IIQ or I-QOL with or without UDI in trials of incontinence treatments
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