713 research outputs found

    Shape and Pose Recovery from Planar Pushing

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    Tactile exploration refers to the use of physical interaction to infer object properties. In this work, we study the feasibility of recovering the shape and pose of a movable object from observing a series of contacts. In particular, we approach the problem of estimating the shape and trajectory of a planar object lying on a frictional surface, and being pushed by a frictional probe. The probe, when in contact with the object, makes observations of the location of contact and the contact normal. Our approach draws inspiration from the SLAM problem, where noisy observations of the location of landmarks are used to reconstruct and locate a static environment. In tactile exploration, analogously, we can think of the object as a rigid but moving environment, and of the pusher as a sensor that reports contact points on the boundary of the object. A key challenge to tactile exploration is that, unlike visual feedback, sensing by touch is intrusive in nature. The object moves by the action of sensing. In the 2D version of the problem that we study in this paper, the well understood mechanics of planar frictional pushing provides a motion model that plays the role of odometry. The conjecture we investigate in this paper is whether the models of frictional pushing are sufficiently descriptive to simultaneously estimate the shape and pose of an object from the cumulative effect of a sequence of pushes.National Science Foundation (U.S.) (Award IIS-1427050

    Exploration and visualization of gene expression with neuroanatomy in the adult mouse brain

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    <p>Abstract</p> <p>Background</p> <p>Spatially mapped large scale gene expression databases enable quantitative comparison of data measurements across genes, anatomy, and phenotype. In most ongoing efforts to study gene expression in the mammalian brain, significant resources are applied to the mapping and visualization of data. This paper describes the implementation and utility of Brain Explorer, a 3D visualization tool for studying <it>in situ </it>hybridization-based (ISH) expression patterns in the Allen Brain Atlas, a genome-wide survey of 21,000 expression patterns in the C57BL6J adult mouse brain.</p> <p>Results</p> <p>Brain Explorer enables users to visualize gene expression data from the C57Bl/6J mouse brain in 3D at a resolution of 100 μm<sup>3</sup>, allowing co-display of several experiments as well as 179 reference neuro-anatomical structures. Brain Explorer also allows viewing of the original ISH images referenced from any point in a 3D data set. Anatomic and spatial homology searches can be performed from the application to find data sets with expression in specific structures and with similar expression patterns. This latter feature allows for anatomy independent queries and genome wide expression correlation studies.</p> <p>Conclusion</p> <p>These tools offer convenient access to detailed expression information in the adult mouse brain and the ability to perform data mining and visualization of gene expression and neuroanatomy in an integrated manner.</p

    Trends in Psychotropic Dispensing Among Older Adults with Dementia Living in Long-Term Care Facilities: 2004-2013.

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    OBJECTIVE: Guidelines worldwide have cautioned against the use of antipsychotics as first-line agents to treat neuropsychiatric symptoms of dementia. We aimed to investigate the changes over time in the dispensing of antipsychotics and other psychotropics among older adults with dementia living in long-term care facilities. METHODS: We used drug claims data from Ontario, Canada, to calculate quarterly rates of prescription dispensing of six psychotropic drug classes among all elderly (≥65 years of age) long-term care residents with dementia from January 1, 2004, to March 31, 2013. Psychotropic drugs were classified into the following categories: atypical and conventional antipsychotics, non-sedative and sedative antidepressants, anti-epileptics, and benzodiazepines. We used time-series analysis to assess trends over time. RESULTS: The study sample increased by 21% over the 10-year study period, from 49,251 patients to 59,785 patients. The majority of patients (within the range of 75%-79%) were dispensed at least one psychotropic medication. At the beginning of the study period atypical antipsychotics (38%) were the most frequently dispensed psychotropic, followed by benzodiazepines (28%), non-sedative antidepressants (27%), sedative antidepressants (17%), anti-epileptics (7%), and conventional antipsychotics (3%). Dispensing of anti-epileptics (2% increase) and conventional antipsychotics (1% decrease) displayed modest changes over time, but we observed more pronounced changes in dispensing of benzodiazepines (11% decrease) and atypical antipsychotics (4% decrease). Concurrently, we observed a substantial growth in the dispensing of both sedative (15% increase) and non-sedative (9% increase) antidepressants. The proportion of patients dispensed two or more psychotropic drug classes increased from 42% in 2004 to 50% in 2013. CONCLUSIONS: Utilization patterns of psychotropic drugs in institutionalized patients with dementia have changed over the past decade. Although their use declined slightly over the study period, atypical antipsychotics continue to be used at a high rate. A decline in the use of benzodiazepines along with an increased use of sedative and non-sedative antidepressants suggests that the latter class of drugs is being substituted for the former in the management of neuropsychiatric symptoms. Psychotropic polypharmacy continues to be highly prevalent in these patient samples

    IsoDOT Detects Differential RNA-isoform Expression/Usage with respect to a Categorical or Continuous Covariate with High Sensitivity and Specificity

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    We have developed a statistical method named IsoDOT to assess differential isoform expression (DIE) and differential isoform usage (DIU) using RNA-seq data. Here isoform usage refers to relative isoform expression given the total expression of the corresponding gene. IsoDOT performs two tasks that cannot be accomplished by existing methods: to test DIE/DIU with respect to a continuous covariate, and to test DIE/DIU for one case versus one control. The latter task is not an uncommon situation in practice, e.g., comparing paternal and maternal allele of one individual or comparing tumor and normal sample of one cancer patient. Simulation studies demonstrate the high sensitivity and specificity of IsoDOT. We apply IsoDOT to study the effects of haloperidol treatment on mouse transcriptome and identify a group of genes whose isoform usages respond to haloperidol treatment
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