94,476 research outputs found

    Race and Policing: An Agenda for Action

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    This paper is organized into two parts -- Strategic Voice and Tactical Agency. Strategic Voice argues that problems of race in policing cannot be resolved by the police alone. Other people must help by understanding and ameliorating the social conditions that cause race to be associated with crime and hence become a dilemma for American policing. Rather than accepting these conditions as givens, police leaders with their powerful collective voice should actively call attention to what needs to be changed. Tactical Agency outlines what the police can do on their own initiative to deal with the operational dilemmas of race -- in the communities they serve and in their own organizations

    Fatigue failure load indicator

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    An indicator for recording the load at which a fatigue specimen breaks during the last cycle of a fatigue test is described. A load cell is attached to the specimen which is alternately subjected to tension and compression loads. The output of the load cell which is proportional to the load on the specimen is applied to the input of a peak detector. Each time the specimen is subjected to a compression load, means are provided for applying a positive voltage to the rest of the peak detector to reset it. During the last cycle of the tension load the peak detector measures the maximum load on the specimen. Means are provided for disconnecting the load cell from the peak detector when there is a failure in the specimen

    Configurations of Handles and the Classification of Divergences in the String Partition Function

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    The divergences that arise in the regularized partition function for closed bosonic string theory in flat space lead to three types of perturbation series expansions, distinguished by their genus dependence. This classification of infinities can be traced to geometrical characteristics of the string worldsheet. Some categories of divergences may be eliminated in string theories formulated on compact manifolds.Comment: 24 pages, DAMTP-R/94/1

    Dunce mutants of Drosophila melanogaster: mutants defective in the cyclic AMP phosphodiesterase enzyme system

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    The cyclic AMP and cyclic GMP phosphodiesterase activities present in flies of six mutant strains of the dunce gene and in the parent wild- type strains are characterized. All of the mutants exhibit aberrant cyclic AMP metabolism. The mutant strains dunceM14, dunceM11, and dunceML appear to be amorphic, because they completely lack the cAMP-specific phosphodiesterase normally present in adult flies. These strains exhibit extremely high levels of cAMP. The mutant strains dunce1, dunce2, and dunceCK are hypomorphic and exhibit reduced levels of the cAMP-specific phosphodiesterase. These strains exhibit less marked increases in cAMP content compared with the three amorphic strains. The dunce2 strain possesses a residual enzyme activity that exhibits anomalous kinetics compared with those of the normal enzyme. The possibility that the dunce locus is the structural gene for the cAMP-specific phosphodiesterase is discussed

    Development of a surface isolation estimation technique suitable for application of polar orbiting satellite data

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    A technique is developed for the estimation of total daily insolation on the basis of data derivable from operational polar-orbiting satellites. Although surface insolation and meteorological observations are used in the development, the algorithm is constrained in application by the infrequent daytime polar-orbiter coverage

    Transformation Based Ensembles for Time Series Classification

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    Until recently, the vast majority of data mining time series classification (TSC) research has focused on alternative distance measures for 1-Nearest Neighbour (1-NN) classifiers based on either the raw data, or on compressions or smoothing of the raw data. Despite the extensive evidence in favour of 1-NN classifiers with Euclidean or Dynamic Time Warping distance, there has also been a flurry of recent research publications proposing classification algorithms for TSC. Generally, these classifiers describe different ways of incorporating summary measures in the time domain into more complex classifiers. Our hypothesis is that the easiest way to gain improvement on TSC problems is simply to transform into an alternative data space where the discriminatory features are more easily detected. To test our hypothesis, we perform a range of benchmarking experiments in the time domain, before evaluating nearest neighbour classifiers on data transformed into the power spectrum, the autocorrelation function, and the principal component space. We demonstrate that on some problems there is dramatic improvement in the accuracy of classifiers built on the transformed data over classifiers built in the time domain, but that there is also a wide variance in accuracy for a particular classifier built on different data transforms. To overcome this variability, we propose a simple transformation based ensemble, then demonstrate that it improves performance and reduces the variability of classifiers built in the time domain only. Our advice to a practitioner with a real world TSC problem is to try transforms before developing a complex classifier; it is the easiest way to get a potentially large increase in accuracy, and may provide further insights into the underlying relationships that characterise the problem

    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
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