2,621 research outputs found

    History and morphology of faulting in the Noctis Labyrinthus-Claritas Fossae Region of Mars

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    The topographically high areas cut by Noctis Labyrinthus, Noctis Fossae, and Claritas Fossae were subjected to only minor resurfacing during and following local tectonic activity. Principal resurfacing materials consist of lava flows from Syria Planum and Tharsis Montes. Thus, these areas preserve much of the fault record produced by tectonism in this region. Although recent geologic maps of the area have been produced from Viking images, the only detailed fault histories available until now were described from Mariner 9 images. Much of the faulting in the Tharsis tectonic province was centered in Syria Planum; therefore, understanding the fault history in this region is critical to understanding the stress history and tectonism of Tharsis as a whole

    Numerical algebraic geometry for model selection and its application to the life sciences

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    Researchers working with mathematical models are often confronted by the related problems of parameter estimation, model validation, and model selection. These are all optimization problems, well-known to be challenging due to non-linearity, non-convexity and multiple local optima. Furthermore, the challenges are compounded when only partial data is available. Here, we consider polynomial models (e.g., mass-action chemical reaction networks at steady state) and describe a framework for their analysis based on optimization using numerical algebraic geometry. Specifically, we use probability-one polynomial homotopy continuation methods to compute all critical points of the objective function, then filter to recover the global optima. Our approach exploits the geometric structures relating models and data, and we demonstrate its utility on examples from cell signaling, synthetic biology, and epidemiology.Comment: References added, additional clarification

    Fertilizer Value of Cattle Dunghills in a Pasture Field

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    There were nearly 2.5 million cattle and calves in Kentucky in 1988. Most of these were maintained under pastureland conditions. Nutrients taken up by pasture plants, consumed by cattle, and re-cycled back onto fields by fecal and urine excretions can be a major source of nutrients for maintaining pastureland productivity. In order to estimate the value of this under grazing conditions, observations were made on a pasture field in Casey County, Kentucky, following stocking of the field with cattle

    Preaching and Culture in Latino Congregations

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    Animal Emotions

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    Animal Emotions: How They Drive Human Behavior gives a concise overview of ancient mammalian emotions deeply rooted in the human brain. Jaak Panksepp, a world-renowned neuroscientist, dedicated his life career to the study of mammalian emotions and he carved out seven distinct emotional systems he called seeking, lust, care, and play (positive emotions), and fear, anger, and sadness (negative emotions), all exerting a tremendous influence on human behavior.Christian Montag, a neuroscientist and psychologist, and a long-time collaborator of Jaak Panksepp, revisits together with Kenneth L. Davis, one of Jaak’s PhD students, Panksepp’s theories and provides the reader with new insights into the nature of emotions and their role as survival tools, both for animals and for humans. They also raise new questions about the background of the research field Jaak Panksepp coined "Affective Neuroscience." How are personality and psychopathology linked to animal emotions? Do animals feel the same way as we do? What are our emotional needs in a digital society, and what is key to a happy life

    Interactions of tectonic, igneous, and hydraulic processes in the North Tharsis Region of Mars

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    Recent work on the north Tharsis of Mars has revealed a complex geologic history involving volcanism, tectonism, flooding, and mass wasting. Our detailed photogeologic analysis of this region found many previously unreported volcanic vents, volcaniclastic flows, irregular cracks, and minor pit chains; additional evidence that volcanic tectonic processes dominated this region throughout Martian geologic time; and the local involvement of these processes with surface and near surface water. Also, photoclinometric profiles were obtained within the region of troughs, simple grabens, and pit chains, as well as average spacings of pits along pit chains. These data were used together with techniques to estimate depths of crustal mechanical discontinuities that may have controlled the development of these features. In turn, such discontinuities may be controlled by stratigraphy, presence of water or ice, or chemical cementation

    Introduction

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    It didn\u27t seem so wrong. It seemed as though I worked my whole life to get where I am, and at the same time, when it was presented to me, it was like this was the time I could start to get back some of the fruits of my labor. 1 —Paul Palmer, former star college football running back, regarding cash payments of more than 5,000hereceivedwhileacollegeseniorfromsportsagentNorbyWalters.Thisepigraphhasremainedinourtextthroughmultipleeditions.Itscontinuedrelevanceisunderscoredbytheironythat,inarecentcourtruling,ajudgepeggedtheminimumdollarfigureforcollegeathletestoreceivedfromlicensingrevenuesat5,000 he received while a college senior from sports agent Norby Walters. This epigraph has remained in our text through multiple editions. Its continued relevance is underscored by the irony that, in a recent court ruling, a judge pegged the minimum dollar figure for college athletes to received from licensing revenues at 5,000. This book, meanwhile, focuses on the evolving sports agent industry, the issues affecting it, and how to improve and regulate it. Key issues and problems associated with sports agents are visible at the high school, collegiate, and professional levels. Whatever the concerns that lie at the center of the sports agent storm, it is a business that captures the attention of many

    Structural Classification of Metal Complexes with Three-Coordinate Centres

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    Attempts to describe the geometry about three-coordinate silver(I) complexes have proven difficult because interatomic angles generally vary wildly and there is no adequate or readily available classification system found in the literature. A search of the Cambridge Structural Database shows that complexes formed between any metal centre and three non-metal donors (18001 examples) usually adopt geometries that are quite different than ideal ‘textbook’ extremes of either trigonal planar (∼4% with α = β = γ = 120 ± 2°), T-shaped (∼0.05% with α = 180 ± 2°, β = γ = 90 ± 2°), or trigonal pyramidal (∼0.3% with α = β = γ = 110 ± 2°). Moreover, there are multiple variations of “Y-type” and “other” shapes that require elaboration. Thus, to assist in future structural descriptions, we developed a classification system that spans all known and yet-to-be-discovered three-coordinate geometries. A spreadsheet has also been constructed that utilizes the “shape-space” approach to extract the structural description from a user input of three angles about a tri-coordinate centre and the number of atoms in a plane. The structures of two silver(I) complexes of new N-donor ligands p-NH2C6H4C6H4CH(pz = pyrazol-1-yl)2, L1, and 2-ferrocenyl-4,5-di(2-pyridyl)imidazole, L2, illustrate the utility of this classification system
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