37 research outputs found

    Coexistence of bounded and unbounded geometry for area-preserving maps

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    The geometry of the period doubling Cantor sets of strongly dissipative infinitely renormalizable H\'enon-like maps has been shown to be unbounded by M. Lyubich, M. Martens and A. de Carvalho, although the measure of unbounded "spots" in the Cantor set has been demonstrated to be zero. We show that an even more extreme situation takes places for infinitely renormalizable area-preserving H\'enon-like maps: bounded and unbounded geometries coexist with both phenomena occuring on subsets of positive measure in the Cantor sets

    On Different Approaches to Syntactic Analysis Into Bi-Lexical Dependencies. An Empirical Comparison of Direct, PCFG-Based, and HPSG-Based Parsers

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    We compare three different approaches to parsing into syntactic, bi-lexical dependencies for English: a ‘direct’ data-driven dependency parser, a statistical phrase structure parser, and a hybrid, ‘deep’ grammar-driven parser. The analyses from the latter two are post-converted to bilexical dependencies. Through this ‘reduction’ of all three approaches to syntactic dependency parsers, we determine empirically what performance can be obtained for a common set of dependency types for English, across a broad variety of domains. In doing so, we observe what trade-offs apply along three dimensions, accuracy, efficiency, and resilience to domain variation. Our results suggest that the hand-built grammar in one of our parsers helps in both accuracy and cross-domain performance. Proceedings of The 13th International Conference on Parsing Technologies IWPT-2013

    Distinct Peripheral Blood RNA Responses to Salmonella in Pigs Differing in Salmonella Shedding Levels: Intersection of IFNG, TLR and miRNA Pathways

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    Transcriptomic analysis of the response to bacterial pathogens has been reported for several species, yet few studies have investigated the transcriptional differences in whole blood in subjects that differ in their disease response phenotypes. Salmonella species infect many vertebrate species, and pigs colonized with Salmonella enterica serovar Typhimurium (ST) are usually asymptomatic, making detection of these Salmonella-carrier pigs difficult. The variable fecal shedding of Salmonella is an important cause of foodborne illness and zoonotic disease. To investigate gene pathways and biomarkers associated with the variance in Salmonella shedding following experimental inoculation, we initiated the first analysis of the whole blood transcriptional response induced by Salmonella. A population of pigs (n = 40) was inoculated with ST and peripheral blood and fecal Salmonella counts were collected between 2 and 20 days post-inoculation (dpi). Two groups of pigs with either low shedding (LS) or persistent shedding (PS) phenotypes were identified. Global transcriptional changes in response to ST inoculation were identified by Affymetrix Genechip® analysis of peripheral blood RNA at day 0 and 2 dpi. ST inoculation triggered substantial gene expression changes in the pigs and there was differential expression of many genes between LS and PS pigs. Analysis of the differential profiles of gene expression within and between PS and LS phenotypic classes identified distinct regulatory pathways mediated by IFN-γ, TNF, NF-κB, or one of several miRNAs. We confirmed the activation of two regulatory factors, SPI1 and CEBPB, and demonstrated that expression of miR-155 was decreased specifically in the PS animals. These data provide insight into specific pathways associated with extremes in Salmonella fecal shedding that can be targeted for further exploration on why some animals develop a carrier state. This knowledge can also be used to develop rational manipulations of genetics, pharmaceuticals, nutrition or husbandry methods to decrease Salmonella colonization, shedding and spread

    The molecular and cellular origin of human prostate cancer

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    Prostate cancer is the most commonly diagnosed male malignancy. Despite compelling epidemiology, there are no definitive aetiological clues linking development to frequency. Pre-malignancies such as proliferative inflammatory atrophy (PIA) and prostatic intraepithelial neoplasia (PIN) yield insights into the initiating events of prostate cancer, as they supply a background "field" for further transformation. An inflammatory aetiology, linked to recurrent prostatitis, and heterologous signalling from reactive stroma and infiltrating immune cells may result in cytokine addiction of cancer cells, including a tumour-initiating population also known as cancer stem cells (CSCs). In prostate tumours, the background mutational rate is rarely exceeded, but genetic change via profound sporadic chromosomal rearrangements results in copy number variations and aberrant gene expression. In cancer, dysfunctional differentiation is imposed upon the normal epithelial lineage, with disruption/disappearance of the basement membrane, loss of the contiguous basal cell layer and expansion of the luminal population. An initiating role for androgen receptor (AR) is attractive, due to the luminal phenotype of the tumours, but alternatively a pool of CSCs, which express little or no AR, has also been demonstrated. Indolent and aggressive tumours may also arise from different stem or progenitor cells. Castrate resistant prostate cancer (CRPC) remains the inevitable final stage of disease following treatment. Time-limited effectiveness of second-generation anti-androgens, and the appearance of an AR-neuroendocrine phenotype imply that metastatic disease is reliant upon the plasticity of the CSC population, and indeed CSC gene expression profiles are most closely related to those identified in CRPCs

    A genome-wide meta-analysis uncovers six sequence variants conferring risk of vertigo.

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    To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadVertigo is the leading symptom of vestibular disorders and a major risk factor for falls. In a genome-wide association study of vertigo (Ncases = 48,072, Ncontrols = 894,541), we uncovered an association with six common sequence variants in individuals of European ancestry, including missense variants in ZNF91, OTOG, OTOGL, and TECTA, and a cis-eQTL for ARMC9. The association of variants in ZNF91, OTOGL, and OTOP1 was driven by an association with benign paroxysmal positional vertigo. Using previous reports of sequence variants associating with age-related hearing impairment and motion sickness, we found eight additional variants that associate with vertigo. Although disorders of the auditory and the vestibular system may co-occur, none of the six genome-wide significant vertigo variants were associated with hearing loss and only one was associated with age-related hearing impairment. Our results uncovered sequence variants associating with vertigo in a genome-wide association study and implicated genes with known roles in inner ear development, maintenance, and disease.UK Biobank Resource European Commission European Commission Joint Research Centre United States Department of Health & Human Services National Institutes of Health (NIH) - US

    Psychosocial impact of undergoing prostate cancer screening for men with BRCA1 or BRCA2 mutations.

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    OBJECTIVES: To report the baseline results of a longitudinal psychosocial study that forms part of the IMPACT study, a multi-national investigation of targeted prostate cancer (PCa) screening among men with a known pathogenic germline mutation in the BRCA1 or BRCA2 genes. PARTICPANTS AND METHODS: Men enrolled in the IMPACT study were invited to complete a questionnaire at collaborating sites prior to each annual screening visit. The questionnaire included sociodemographic characteristics and the following measures: the Hospital Anxiety and Depression Scale (HADS), Impact of Event Scale (IES), 36-item short-form health survey (SF-36), Memorial Anxiety Scale for Prostate Cancer, Cancer Worry Scale-Revised, risk perception and knowledge. The results of the baseline questionnaire are presented. RESULTS: A total of 432 men completed questionnaires: 98 and 160 had mutations in BRCA1 and BRCA2 genes, respectively, and 174 were controls (familial mutation negative). Participants' perception of PCa risk was influenced by genetic status. Knowledge levels were high and unrelated to genetic status. Mean scores for the HADS and SF-36 were within reported general population norms and mean IES scores were within normal range. IES mean intrusion and avoidance scores were significantly higher in BRCA1/BRCA2 carriers than in controls and were higher in men with increased PCa risk perception. At the multivariate level, risk perception contributed more significantly to variance in IES scores than genetic status. CONCLUSION: This is the first study to report the psychosocial profile of men with BRCA1/BRCA2 mutations undergoing PCa screening. No clinically concerning levels of general or cancer-specific distress or poor quality of life were detected in the cohort as a whole. A small subset of participants reported higher levels of distress, suggesting the need for healthcare professionals offering PCa screening to identify these risk factors and offer additional information and support to men seeking PCa screening

    Properties of invariant sets in certain two-dimensional dynamical systems : Renormalization and beyond

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    This thesis consists of an introduction and four research papers concerning dynamical systems, focusing on renormalization in two dimensions. Paper I (joint with Jordi-Lluís Figueras) studies a generalization of the anti-integrable limit of skew-product systems based on a Frenkel-Kontorova model. It is shown that under certain regularity conditions the orbits of such a system has a Cantor set structure and the existence of a non-smooth folding bifurcation is deduced. Paper II studies the invariant Cantor sets of period doubling type of infinitely renormalizable area-preserving maps in the universality class of the Eckmann-Koch-Wittwer renormalization fixed point. It is shown that for such maps the invariant Cantor set is always contained in a Lipschitz curve but never in a smooth (meaning C1) curve. Paper III (joint with Denis Gaidashev) continues the study of the invariant Cantor sets of infinitely renormalizable area-preserving maps, focusing on their geometry. It is shown that there is always a positive measure of unbounded geometry. Additionally, some results giving control over the average expansion of vectors by the renormalization microscope are also provided Finally paper IV (joint with Denis Gaidashev) considers renormalization of two-dimensional perturbations of almost commuting pairs of holomorphic maps. A renormalization operator is developed and statements about the hyperbolicity, universality and non-rigidity of this operator are proven

    On the Invariant Cantor Sets of Period Doubling Type of Infinitely Renormalizable Area-Preserving Maps

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    Since its inception in the 1970s at the hands of Feigenbaum and, independently, Coullet and Tresser the study of renormalization operators in dynamics has been very successful at explaining universality phenomena observed in certain families of dynamical systems. The first proof of existence of a hyperbolic fixed point for renormalization of area-preserving maps was given by Eckmann et al. (Mem Am Math Soc 47(289):vi+122, 1984). However, there are still many things that are unknown in this setting, in particular regarding the invariant Cantor sets of infinitely renormalizable maps. In this paper we show that the invariant Cantor set of period doubling type of any infinitely renormalizable area-preserving map in the universality class of the Eckmann-Koch-Wittwer renormalization fixed point is always contained in a Lipschitz curve but never contained in a smooth curve. This extends previous results by de Carvalho, Lyubich and Martens about strongly dissipative maps of the plane close to unimodal maps to the area-preserving setting. The method used for constructing the Lipschitz curve is very similar to the method used in the dissipative case but proving the nonexistence of smooth curves requires new techniques

    Properties of invariant sets in certain two-dimensional dynamical systems : Renormalization and beyond

    No full text
    This thesis consists of an introduction and four research papers concerning dynamical systems, focusing on renormalization in two dimensions. Paper I (joint with Jordi-Lluís Figueras) studies a generalization of the anti-integrable limit of skew-product systems based on a Frenkel-Kontorova model. It is shown that under certain regularity conditions the orbits of such a system has a Cantor set structure and the existence of a non-smooth folding bifurcation is deduced. Paper II studies the invariant Cantor sets of period doubling type of infinitely renormalizable area-preserving maps in the universality class of the Eckmann-Koch-Wittwer renormalization fixed point. It is shown that for such maps the invariant Cantor set is always contained in a Lipschitz curve but never in a smooth (meaning C1) curve. Paper III (joint with Denis Gaidashev) continues the study of the invariant Cantor sets of infinitely renormalizable area-preserving maps, focusing on their geometry. It is shown that there is always a positive measure of unbounded geometry. Additionally, some results giving control over the average expansion of vectors by the renormalization microscope are also provided Finally paper IV (joint with Denis Gaidashev) considers renormalization of two-dimensional perturbations of almost commuting pairs of holomorphic maps. A renormalization operator is developed and statements about the hyperbolicity, universality and non-rigidity of this operator are proven

    Manipulation for Acquisition of mathematics ideas of 5-6 years old pupils

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    Kvalifikācijas darba autore: Marina Larionova. Kvalifikācijas darba nosaukums: Priekšmetiskā darbība matemātikas priekšstatu apguves veicināšanā 5-6 g. vecuma bērniem. Darba mērķis: teorētiski un praktiski pētīt vecākā pirmsskolas vecumposma bērnu priekšmetisko darbību un apkopot ieteikumus matemātikas priekšstatu apguves veicināšanā 5-6 g. vecuma bērniem. Darbs sastāv: ievads, 2 (divas) daļas, 4 (četras) apakšnodaļas, secinājumi, 60 (sešdesmit) literatūras un avotu saraksts, 17 (septiņpadsmit) pielikumi. Kvalifikācijas darba apjoms: 55 lpp., darbā 7 tabulas, 7attēli, 17 pielikumi. Pirmajā daļā tiek analizēta daudzu zinātnieku un autoru teorija par matemātikas priekšstatiem un to apguvi pirmsskolā, un raksturota priekšmetiskā darbības būtība priekšstatu apguves veicināšanā 5-6 g. vecuma bērniem. Otrajā daļā tiek pētīta reālā situācija matemātikas priekšstatu apguvē. Kā arī tiek piedāvāti ieteikumi, lai veicinātu šo priekšstatu apguvi. Atslēgas vārdi: priekšmetiskā darbība, matemātiskie priekšstati, 5-6 g. vecuma bērni, pirmskola.Author of the qualification paper: Marina Larionova. Title of the qualification paper: Manipulation for Acquisition of mathematics ideas of 5-6 years old pupils. Objective of the paper: to study in theory and practice the Manipulation for Acquisition in older preschool-age children and sum-up recommendations of mathematics ideas of 5-6 years old pupils. The paper consists: the introduction, 2 (two) chapters, 4 (four) subdivisions, conclusions, 60 (sixty) units of literature and a list of sources, 17 (seventeen) of the annexes. Extent of the qualification paper: 55 pages, 7 tables, 7 figures, 17 annexes. The first chapter analyzes many scholars and authors the theory about mathematical ideas and acquisitions in the pre-school, and presents Manipulation for Acquisition essence of mathematics ideas of 5-6 years old pupils. The second chapter explores the real situation for Acquisition of mathematics ideas. And are being made recommendations for promote manipulation of acquisition. Keywords: Manipulation for Acquisition, mathematics ideas, 5-6 years old pupils, pre-school
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