1,141 research outputs found

    Identification of gene pathways implicated in Alzheimer's disease using longitudinal imaging phenotypes with sparse regression

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    We present a new method for the detection of gene pathways associated with a multivariate quantitative trait, and use it to identify causal pathways associated with an imaging endophenotype characteristic of longitudinal structural change in the brains of patients with Alzheimer's disease (AD). Our method, known as pathways sparse reduced-rank regression (PsRRR), uses group lasso penalised regression to jointly model the effects of genome-wide single nucleotide polymorphisms (SNPs), grouped into functional pathways using prior knowledge of gene-gene interactions. Pathways are ranked in order of importance using a resampling strategy that exploits finite sample variability. Our application study uses whole genome scans and MR images from 464 subjects in the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. 66,182 SNPs are mapped to 185 gene pathways from the KEGG pathways database. Voxel-wise imaging signatures characteristic of AD are obtained by analysing 3D patterns of structural change at 6, 12 and 24 months relative to baseline. High-ranking, AD endophenotype-associated pathways in our study include those describing chemokine, Jak-stat and insulin signalling pathways, and tight junction interactions. All of these have been previously implicated in AD biology. In a secondary analysis, we investigate SNPs and genes that may be driving pathway selection, and identify a number of previously validated AD genes including CR1, APOE and TOMM40

    Quiz Games as a model for Information Hiding

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    We present a general computation model inspired in the notion of information hiding in software engineering. This model has the form of a game which we call quiz game. It allows in a uniform way to prove exponential lower bounds for several complexity problems of elimination theory.Comment: 46 pages, to appear in Journal of Complexit

    The LMT Galaxies' 3 mm Spectroscopic Survey: First Results

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    The molecular phase of the interstellar medium (ISM) in galaxies offers fundamental insight for understanding star-formation processes and how stellar feedback affects the nuclear activity of certain galaxies. We present here Large Millimeter Telescope spectra obtained with the Redshift Search Receiver, a spectrograph that cover simultaneously the 3 mm band from 74 to 111 GHz with a spectral resolution of around 100 km/s. The observed galaxies that have been detected previously in HCN, have different degrees of nuclear activity, one normal galaxy (NGC 6946), the starburst prototype (M 82) and two ultraluminous infrared galaxies (ULIRGs, IRAS 17208-0014 and Mrk 231). We plotted our data in the HCO+/HCN vs. HCN/13CO diagnostic diagram finding that NGC 6946 and M 82 are located close to other normal galaxies; and that both IRAS 17208-0014 and Mrk 231 are close to the position of the well known ULIRG Arp 220 reported by Snell et al. (2011). We found that in Mrk 231 -- a galaxy with a well known active galactic nucleus -- the HCO+/HCN ratio is similar to the ratio observed in other normal galaxies.Comment: Proceedings to appear in "Massive Young Star Clusters Near and Far: From the Milky Way to Reionization", 2013 Guillermo Haro Conference. Eds. Y. D. Mayya, D. Rosa-Gonzalez, & E. Terlevich, INAOE and AMC. 5 pages, 1 figur

    Mediterranean House Geckos Exploit Novel Resources in a Recipient Lizard Assemblage

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    A speciesā€™ ecological niche represents the environmental conditions needed for an individual to replace itself and is comprised of multiple resource axes (Pianka 2000 Evol. Ecol.). One mechanism of establishment of non-native species is via exploitation of novel resources in recipient ecosystems through their unique functional traits (Schalk et al. 2018 Biol. Invas.). Mediterranean House Geckos (Hemidactylus turcicus) are an exotic species introduced in urban areas across Texas, yet little is known about their resource use relative to native lizards. We hypothesized that H. turcicus would exhibit low overlap in resource use in their habitat, dietary, and isotopic niches compared to native lizard species (Green Anole [Anolis carolinensis], Little Brown Skink [Scincella lateralis], Five-lined Skink [Plestiodon fasciatus])

    Visuospatial skills in children affected by primary nocturnal enuresis: Rehabilitative proposals

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    The sphincterial control problems in childhood are very common, with relevant comorbidities (i.e.: difficulty in academic performance, sleep disturbances, minor neurological signs) involved in the complex process of maturation and learning, such as to cause a great deal of discomfort and related disorders in affected subjects. Enuresis is characterized by the involuntary urination in the absence of a physical disorder, socially unacceptable in places and at one stage of life where such control is acquired by the majority of subjects (about 5 years). The present study aims to evaluate the visuospatial skills in children affected by primary monosymptomatic nocturnal enuresis (PMNE). 31 PMNE children (16 males and 15 females) (mean age 10.87, SD Ā± 1.68) and 61 healthy children (32 males, 29 females) (mean age 11.03, SD Ā± 1.85, p = 0687) were evaluated for visuomotor skills with the Visual-Motor Integration Scale (VMI). PMNE subjects show a worse performance on average to VMI, especially in the total visual-motor integration test. This finding emphasizes the importance of a framework for global and more complex than is commonly implemented, across the border but framing the subject of enuretic symptoms in a more global perspective
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