22,828 research outputs found

    An aseismic slip pulse in northern Chile and along-strike variations in seismogenic behavior

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    We use interferometric synthetic aperture radar, GPS, and seismic observations spanning 5 to 18 years to reveal a detailed kinematic picture of the spatiotemporal evolution of fault slip in a region corresponding to the 30 July 1995 M_w 8.1 subduction zone megathrust earthquake in northern Chile. In a single area, we document a complex mosaic of phenomena including large earthquakes, postseismic afterslip with a spatial distribution that appears to be tied to variations in coastal morphology, and a completely aseismic pulse that may have triggered a M_w 7.1 earthquake on 30 January 1998. In contrast to simple models of fault slip behavior, this spatial heterogeneity indicates that frictional parameters on the fault do not have a systematic transition with depth and also vary rapidly along strike. The low amount of afterslip from the M_w 8.1 earthquake relative to other similar events suggests that postseismic behavior may be modulated by the amount of sediment subducted

    Comparison of Harvested and Nonharvested Painted Turtle Populations

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    Painted turtles (Chrysemys picta) are commercially harvested in large numbers in Minnesota for sale to biological supply companies and the pet trade. We investigated the possible effects of this harvest by comparing size, demography, and catch rates of painted turtles in 12 harvested and 10 nonharvested painted turtle populations in 2001 and 2002. We correlated turtle catch rates to harvest status, and harvested lakes had a lower catch-per-unit-effort than nonharvested lakes. Harvest had minimal effect on the size of turtles captured, and we found no significant differences in the count of male:female:juvenile turtles among lakes of different harvest status. We suggest that painted turtle populations likely have been impacted by harvester activities, but it was unclear whether the current harvest is sustainable. Further work is needed to determine whether there are any long-term effects on painted turtle populations

    New results on q-positivity

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    In this paper we discuss symmetrically self-dual spaces, which are simply real vector spaces with a symmetric bilinear form. Certain subsets of the space will be called q-positive, where q is the quadratic form induced by the original bilinear form. The notion of q-positivity generalizes the classical notion of the monotonicity of a subset of a product of a Banach space and its dual. Maximal q-positivity then generalizes maximal monotonicity. We discuss concepts generalizing the representations of monotone sets by convex functions, as well as the number of maximally q-positive extensions of a q-positive set. We also discuss symmetrically self-dual Banach spaces, in which we add a Banach space structure, giving new characterizations of maximal q-positivity. The paper finishes with two new examples.Comment: 18 page

    Leveraged Public to Private Transactions in the UK

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    This paper examines the magnitude and the sources of the expected shareholder gains in UK public to private transactions (PTPs) in the second wave from 1997-2003.Pre-transaction shareholders on average receive a premium of 40% and the share price reaction to the PTP announcement is about 30%.The main sources of the shareholder wealth gains are undervaluation of the pre-transaction target firm, increased interest tax shields and incentive realignment.An expected reduction of free cash flows does not determine the premiums nor are PTPs a defensive reaction against a takeover.Public to private;going-private;LBO;MBO;IBO;Management buyins;Management buyouts;Leveraged buyouts

    Linear LL-positive sets and their polar subspaces

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    In this paper, we define a Banach SNL space to be a Banach space with a certain kind of linear map from it into its dual, and we develop the theory of linear LL-positive subsets of Banach SNL spaces with Banach SNL dual spaces. We use this theory to give simplified proofs of some recent results of Bauschke, Borwein, Wang and Yao, and also of the classical Brezis-Browder theorem.Comment: 11 pages. Notational changes since version

    Modeling of Technical Capacity and Cost Structure in Flexible Manufacturing Systems

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    The purpose of this paper is to create a basis for modeling of technical performance and cost structure in flexible manufacturing systems (FMS). Time sharing between manufacturing phases and the cost of the system parts and implementing activities are considered. The technical performance is divided into theoretical capacity and difficulties and trade offs. The flexibility is also considered. The costs are studied separately for nine features. In addition to the hardware, software and working costs are the effects of standardization and modularization studied. In the second part of the paper the FMS-model of Ranta and Alabian has been critically reviewed and some ideas for modification are presented. Finally some of the lessons learned during this work are listed

    A specific brain structural basis for individual differences in reality monitoring.

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    Much recent interest has centered on understanding the relationship between brain structure variability and individual differences in cognition, but there has been little progress in identifying specific neuroanatomical bases of such individual differences. One cognitive ability that exhibits considerable variability in the healthy population is reality monitoring; the cognitive processes used to introspectively judge whether a memory came from an internal or external source (e.g., whether an event was imagined or actually occurred). Neuroimaging research has implicated the medial anterior prefrontal cortex (PFC) in reality monitoring, and here we sought to determine whether morphological variability in a specific anteromedial PFC brain structure, the paracingulate sulcus (PCS), might underlie performance. Fifty-three healthy volunteers were selected on the basis of MRI scans and classified into four groups according to presence or absence of the PCS in their left or right hemisphere. The group with absence of the PCS in both hemispheres showed significantly reduced reality monitoring performance and ability to introspect metacognitively about their performance when compared with other participants. Consistent with the prediction that sulcal absence might mean greater volume in the surrounding frontal gyri, voxel-based morphometry revealed a significant negative correlation between anterior PFC gray matter and reality monitoring performance. The findings provide evidence that individual differences in introspective abilities like reality monitoring may be associated with specific structural variability in the PFC

    Sensor data to measure Hawthorne effects in cookstove evaluation.

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    This data in brief article includes estimated time cooking based on temperature sensor data taken every 30 min from three stone fires and introduced fuel-efficient Envirofit stoves in approximately 168 households in rural Uganda. These households were part of an impact evaluation study spanning about six months to understand the effects of fuel-efficient cookstoves on fuel use and pollution. Daily particulate matter (pollution) and fuelwood use data are also included. This data in brief file only includes the weeks prior to, during, and after an in-person measurement team visited each home. The data is used to analyze whether households change cooking patterns when in-person measurement teams are present versus when only the temperature sensor is in the home
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