132 research outputs found

    Connecting Tables with Allowing Negative Cell Counts

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    It is well-known that computing a Markov basis for a discrete loglinear model is very hard in general. Thus, we focus on connecting tables in a fiber via a subset of a Markov basis and in this paper, we consider connecting tables if we allow cell counts in each tale to be −1-1. In this paper we show that if a subset of a Markov basis connects all tables in the fiber which contains a table with all ones, then moves in this subset connect tables in the fiber if we allow cell counts to be −1-1. In addition, we show that in some cases under the no-three-way interaction model, we can connect tables by all basic moves of 2×2×22 \times 2 \times 2 minors with allowing Xijk≥−1X_{ijk} \geq -1. We then apply this Markov Chain Monte Carlo (MCMC) scheme to an empirical data on Naval officer and enlisted population. Our computational experiments show it works well and we end with the conjecture on the no-three-way interaction model.Comment: 12 page

    Hit and Run Sampling from Tropically Convex Sets

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    In this paper we propose Hit and Run (HAR) sampling from a tropically convex set. The key ingredient of HAR sampling from a tropically convex set is sampling uniformly from a tropical line segment over the tropical projective torus, which runs linearly in its computational time complexity. We show that this HAR sampling method samples uniformly from a tropical polytope which is the smallest tropical convex set of finitely many vertices. Finally, we apply this novel method to any given distribution using Metropolis-Hasting filtering over a tropical polytope

    Tropical Geometric Tools for Machine Learning: the TML package

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    In the last decade, developments in tropical geometry have provided a number of uses directly applicable to problems in statistical learning. The TML package is the first R package which contains a comprehensive set of tools and methods used for basic computations related to tropical convexity, visualization of tropically convex sets, as well as supervised and unsupervised learning models using the tropical metric under the max-plus algebra over the tropical projective torus. Primarily, the TML package employs a Hit and Run Markov chain Monte Carlo sampler in conjunction with the tropical metric as its main tool for statistical inference. In addition to basic computation and various applications of the tropical HAR sampler, we also focus on several supervised and unsupervised methods incorporated in the TML package including tropical principal component analysis, tropical logistic regression and tropical kernel density estimation

    Serotonergic antidepressant effects on aggressive, self-injurious and destructive/disruptive behaviours in intellectually disabled adults: a retrospective, open-label, naturalistic trial

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    There is a growing body of evidence that serotonergic antidepressants are useful in the treatment of maladaptive behaviours in the intellectually disabled. However, not all studies have shown positive results due to lack of efficacy, tolerance development, and troublesome side-effects. The current study consisted of a review of the treatment response to a variety of serotonergic antidepressants, consisting of selective serotonin reuptake inhibitors (SSRIs )

    The influence of tumor regression, solar elastosis, and patient age on pathologists\u27 interpretation of melanocytic skin lesions.

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    It is not known whether patient age or tumor characteristics such as tumor regression or solar elastosis influence pathologists\u27 interpretation of melanocytic skin lesions (MSLs). We undertook a study to determine the influence of these factors, and to explore pathologist\u27s characteristics associated with the direction of diagnosis. To meet our objective, we designed a cross-sectional survey study of pathologists\u27 clinical practices and perceptions. Pathologists were recruited from diverse practices in 10 states in the United States. We enrolled 207 pathologist participants whose practice included the interpretation of MSLs. Our findings indicated that the majority of pathologists (54.6%) were influenced toward a less severe diagnosis when patients were70 years of age, or by the presence of tumor regression or solar elastosis (58.5%, 71.0%, and 57.0%, respectively). Generally, pathologists with dermatopathology board certification and/or a high caseload of MSLs were more likely to be influenced, whereas those with more years\u27 experience interpreting MSL were less likely to be influenced. Our findings indicate that the interpretation of MSLs is influenced by patient age, tumor regression, and solar elastosis; such influence is associated with dermatopathology training and higher caseload, consistent with expertise and an appreciation of lesion complexity

    Measurement of the lateral distribution function of UHECR air showers with the Pierre Auger Observatory

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    We describe how the lateral distribution function (LDF) is measured using the large sample of events recorded with the surface detector (SD) array and with a small sample observed with the fluorescence detectors (FD). For hybrid events, in which SD and FD measurements of the same shower are available, the core position is much better constrained than for SD-onlyevents, thus providing an important cross-check on the LDF determined from SD measurements alone. [Segmento extraído de la ponencia]Facultad de Ciencias Exacta

    Lysosome-mediated processing of chromatin in senescence

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    Cellular senescence is a stable proliferation arrest, a potent tumor suppressor mechanism, and a likely contributor to tissue aging. Cellular senescence involves extensive cellular remodeling, including of chromatin structure. Autophagy and lysosomes are important for recycling of cellular constituents and cell remodeling. Here we show that an autophagy/lysosomal pathway processes chromatin in senescent cells. In senescent cells, lamin A/C–negative, but strongly γ-H2AX–positive and H3K27me3-positive, cytoplasmic chromatin fragments (CCFs) budded off nuclei, and this was associated with lamin B1 down-regulation and the loss of nuclear envelope integrity. In the cytoplasm, CCFs were targeted by the autophagy machinery. Senescent cells exhibited markers of lysosomal-mediated proteolytic processing of histones and were progressively depleted of total histone content in a lysosome-dependent manner. In vivo, depletion of histones correlated with nevus maturation, an established histopathologic parameter associated with proliferation arrest and clinical benignancy. We conclude that senescent cells process their chromatin via an autophagy/lysosomal pathway and that this might contribute to stability of senescence and tumor suppression
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