309 research outputs found

    Outcome Prediction for Unipolar Depression

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    Although effective drug and non-drug treatment for unipolar depressive illness exist, different individuals respond differently to different treatments. It is not uncommon for a given patient to lw switched several times from one treatment to another until an effective remedy for that particular patient is found. This process is costly in terms of time, money and suffering. It is thus desirable to determine at the outset the likdy response of a patient to the available treatments, so that the optimal one can be selected. Although prior attempts at outcome prediction with linear regression models have failed, recent work on this problem has indicated that the nonlinear predictive techniques of backpropagation and quadratic regression call account for a significant proportion of the variance in the data. The present research applies the nonlinear predictive technique of kernel regression to this problcrn, and employs cross-validation to test the ability of the resulting model to extract, from extremely noisy dinical data, information with predictive value. The importance of comparison with a suitable null hypothesis is illustrated.Office of Naval Research (N00014-95-1-0409

    Environmental enrichment, sexual dimorphism, and brain size in sticklebacks

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    Evidence for phenotypic plasticity in brain size and the size of different brain parts is widespread, but experimental investigations into this effect remain scarce and are usually conducted using individuals from a single population. As the costs and benefits of plasticity may differ among populations, the extent of brain plasticity may also differ from one population to another. In a common garden experiment conducted with three-spined sticklebacks (Gasterosteus aculeatus) originating from four different populations, we investigated whether environmental enrichment (aquaria provided with structural complexity) caused an increase in the brain size or size of different brain parts compared to controls (bare aquaria). We found no evidence for a positive effect of environmental enrichment on brain size or size of different brain parts in either of the sexes in any of the populations. However, in all populations, males had larger brains than females, and the degree of sexual size dimorphism (SSD) in relative brain size ranged from 5.1 to 11.6% across the populations. Evidence was also found for genetically based differences in relative brain size among populations, as well as for plasticity in the size of different brain parts, as evidenced by consistent size differences among replicate blocks that differed in their temperature.Peer reviewe

    Heterochronic development of lateral plates in the three-spined stickleback induced by thyroid hormone level alterations

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    The three-spined stickleback Gasterosteus aculeatus is an important model for studying microevolution and parallel adaptation to freshwater environments. Marine and freshwater forms differ markedly in their phenotype, especially in the number of lateral plates, which are serially repeated elements of the exoskeleton. In fishes, thyroid hormones are involved in adaptation to salinity, as well as the developmental regulation of serially repeated elements. To study how thyroid hormones influence lateral plate development, we manipulated levels of triiodothyronine and thiourea during early ontogeny in a marine and freshwater population with complete and low plate phenotypes, respectively. The development of lateral plates along the body and keel was heterochronic among experimental groups. Fish with a low dosage of exogenous triiodothyronine and those treated with thiourea exhibited retarded development of bony plates compared to both control fish and those treated with higher a triiodothyronine dosage. Several triiodothyronine-treated individuals of the marine form expressed the partial lateral plate phenotype. Some individuals with delayed development of lateral plates manifested 1-2 extra bony plates located above the main row of lateral plates.Peer reviewe

    Erosion Mitigation at Fort Hase Beach and at Pyramid Rock Recreational Areas

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    The U.S. Marine Corps Base Hawaii is responsible for management of the military lands at Mokapu Peninsula in the Kaneohe Bay area, on the island of Oahu, including the shoreline recreational areas known as Fort Hase and Pyramid Rock Beaches. These two beach parks are popular recreational sites and are used extensively by military personnel. The beach at Pyramid Rock Recreational Subarea is also open to the general public on weekends. Unfortunately, this use has resulted in considerable stress to the physical characteristics of the parks. The lack of directional walkways has led to multiple paths across and through the dune vegetation. Inadequate drainage from a shower facility and rainfall runoff have led to erosion in the parking lot at Pyramid Rock Recreational Subarea. High waves have exacerbated the erosion caused by unregulated foot traffic at the Fort Hase beach park, in particular, and have led to the formation of a .5 meter coastal escarpment at the Fort Hase beach and the exposure of an archaeological site. To assure effective and informed management of their coastal and cultural resources, the Marine Corps Base Hawaii (MCBH) is interested in developing methods to mitigate coastal erosion problems and to simultaneously improve the recreational use of these beach parks in accordance with their administrative directives and need to comply with federal statutes. Hence, the purpose of this study has been to examine the environmental characteristics of the two recreational parks; Fort Hase and Pyramid Rock beaches, and to make recommendations on non-structural ways to mitigate both anthropogenic and natural impacts to these parks while assuring that historical and cultural resources are protected.Ogden Environmental and Energy Services Co., Inc

    Resurgence of Sleeping Sickness in Tambura County, Sudan

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    Endemic foci of human African trypanosomiasis are present in southern Sudan. In 1996 and 1997, trypanosomiasis increased sharply in Tambura County. To define the magnitude and geographic distribution of the outbreak, we conducted a prevalence survey using population-based cluster sampling in 16 villages: 1,358 participants answered questions about routine activities and tsetse fly contact and received serologic testing. Seroprevalence in the surveyed area was 19.4% (95% confidence interval = 16.9%, 21.8%). We confirmed infection in 66% of seropositive persons who received one parasitologic examination and in 95% of those who had serial examinations of lymph node fluid and blood. Activities related to the civil war, such as temporary migration, were not associated with seropositive status. Since the previous population screening in 1988, the trypanosomiasis prevalence increased two orders of magnitude, and the proportion of villages affected increased from 54% to 100%. Our results suggest that there may be 5,000 cases in Tambura County. The absence of trypanosomiasis control for nearly a decade is a factor in the resurgence of the disease

    Efficient Acoustic Feature Computation Using FPGAs

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    Many recent advances in music information retrieval (MIR) have been data-driven. Widespread performance evaluations on common data sets, like the annual MIREX events, have been instrumental in advancing the field. Such endeavors incur large computational costs and could potentially benefit from faster calculation of acoustic features. Traditional cluster-based solutions are expensive and space- and power inefficient. The massively parallel architecture of the field programmable gate array (FPGA) makes it possible to design lower-cost, applicationspecific chips rivaling cluster speed for large-scale acoustic feature computation. Such devices also show potential for implementations of MIR systems on embedded devices where hardware acceleration is a necessity. We present a prototype Xilinx System Generator (XSG) library for acoustic feature calculation. We use a genre classification task to compare the performance of simulated hardware features to those computed using standard methods. Finally, we discuss ongoing efforts toward a working hardware design

    UPC++: A high-performance communication framework for asynchronous computation

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    UPC++ is a C++ library that supports high-performance computation via an asynchronous communication framework. This paper describes a new incarnation that differs substantially from its predecessor, and we discuss the reasons for our design decisions. We present new design features, including future-based asynchrony management, distributed objects, and generalized Remote Procedure Call (RPC). We show microbenchmark performance results demonstrating that one-sided Remote Memory Access (RMA) in UPC++ is competitive with MPI-3 RMA; on a Cray XC40 UPC++ delivers up to a 25% improvement in the latency of blocking RMA put, and up to a 33% bandwidth improvement in an RMA throughput test. We showcase the benefits of UPC++ with irregular applications through a pair of application motifs, a distributed hash table and a sparse solver component. Our distributed hash table in UPC++ delivers near-linear weak scaling up to 34816 cores of a Cray XC40. Our UPC++ implementation of the sparse solver component shows robust strong scaling up to 2048 cores, where it outperforms variants communicating using MPI by up to 3.1x. UPC++ encourages the use of aggressive asynchrony in low-overhead RMA and RPC, improving programmer productivity and delivering high performance in irregular applications
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