289 research outputs found

    Ending Laminations and Cannon-Thurston Maps

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    In earlier work, we had shown that Cannon-Thurston maps exist for Kleinian surface groups. In this paper we prove that pre-images of points are precisely end-points of leaves of the ending lamination whenever the Cannon-Thurston map is not one-to-one. In particular, the Cannon-Thurston map is finite-to-one. This completes the proof of the conjectural picture of Cannon-Thurston maps for surface groups.Comment: v4: Final version 22pgs 2figures. Includes the main theorem of the appendix arXiv:1002.2090 by Shubhabrata Das and Mahan Mj. To appear in Geometric and Functional Analysi

    “I want to do it all day!” – Students’ experiences of classroom movement integration

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    Whole-of-school physical activity programming is being advocated internationally, with movement integration in the classroom considered an effective method to increase physical activity throughout the school day. Students (N = 135) from two primary schools in the West of Ireland participated in this study. Data were collected using draw-and-write (N = 135) and focus group interviews (N = 24). Three themes were evident across data types and revealed that students thought the Moving to Learn Ireland active lessons were fun, that they learned academic content better, and the lessons contributed to their fitness development. In conclusion, children who participated in this study positively perceived movement integration lessons in their classrooms. The results of this study can inform future movement integration interventions

    On hyperbolic once-punctured-torus bundles III: Comparing two tessellations of the complex plane

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    To each once-punctured-torus bundle, TϕT_\phi, over the circle with pseudo-Anosov monodromy ϕ\phi, there are associated two tessellations of the complex plane: one, Δ(ϕ)\Delta(\phi), is (the projection from \infty of) the triangulation of a horosphere at \infty induced by the canonical decomposition into ideal tetrahedra, and the other, CW(ϕ)CW(\phi), is a fractal tessellation given by the Cannon-Thurston map of the fiber group switching back and forth between gray and white each time it passes through \infty. In this paper, we study the relation between Δ(ϕ)\Delta(\phi) and CW(ϕ)CW(\phi).Comment: Version 1. 43 pages. 13 .eps figure

    A microplate technique to simultaneously assay calcium accumulation in endoplasmic reticulum and SERCA release of inorganic phosphate

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    Traditional analyses of calcium homeostasis have separately quantified either calcium accumulation or release mechanisms. To define the system as a whole, however, requires multiple experimental techniques to examine both accumulation and release. Here we describe a technique that couples the simultaneous quantification of radio-labeled calcium accumulation in endoplasmic reticulum (ER) microsomes with the release of inorganic phosphate (Pi) by the hydrolytic activity of sarco-endoplasmic reticulum calcium ATPase (SERCA) all in the convenience of a 96-well format

    Impact of gonadectomy on blood pressure regulation in ageing male and female rats

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    Sexual dimorphism in blood pressure has been associated with differential expression of the angiotensin II (AII) receptors and with activity of the nervous system. It is generally accepted that aging affects kidney function as well as autonomic nervous system and hormonal balance. Given that hypertension is more prevalent in men than women until women reach their seventh decade we hypothesised that females would be relatively protected from adverse effects of ageing compared to males, and that this would be mediated by the protective effect of ovarian steroids. Intact and gonadectomised male and female normotensive Wistar rats aged 6, 12 and 18 months were used to study renal function, blood pressure, heart rate and blood pressure variability. We observed that intact females had lower levels of proteinuria and higher (12.5%) creatinine clearance compared to intact males, and that this difference was abolished by castration but not by ovariectomy. Ovariectomy resulted in a change by 9% in heart rate, resulting in similar cardiovascular parameters to those observed in males or gonadectomised males. Spectral analysis of systolic blood pressure revealed that high frequency power spectra were significantly elevated in the females vs. males and were reduced by ovariectomy. Taken altogether the results show that females are protected from age-related declining renal function and to a lesser extent from rising blood pressure in comparison to males. Whilst ovariectomy had some deleterious effects in females, the strongest effects were associated with gonadectomy in males, suggesting a damaging effect of male hormones

    The Genetics and Genomics of Virus Resistance in Maize

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    Viruses cause significant diseases on maize worldwide. Intensive agronomic practices, changes in vector distribution, and the introduction of vectors and viruses into new areas can result in emerging disease problems. Because deployment of resistant hybrids and cultivars is considered to be both economically viable and environmentally sustainable, genes and quantitative trait loci for most economically important virus diseases have been identified. Examination of multiple studies indicates the importance of regions of maize chromosomes 2, 3, 6, and 10 in virus resistance. An understanding of the molecular basis of virus resistance in maize is beginning to emerge, and two genes conferring resistance to sugarcane mosaic virus, Scmv1 and Scmv2, have been cloned and characterized. Recent studies provide hints of other pathways and genes critical to virus resistance in maize, but further work is required to determine the roles of these in virus susceptibility and resistance. This research will be facilitated by rapidly advancing technologies for functional analysis of genes in maize

    Joint QTL Linkage Mapping for Multiple-Cross Mating Design Sharing One Common Parent

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    BACKGROUND: Nested association mapping (NAM) is a novel genetic mating design that combines the advantages of linkage analysis and association mapping. This design provides opportunities to study the inheritance of complex traits, but also requires more advanced statistical methods. In this paper, we present the detailed algorithm of a QTL linkage mapping method suitable for genetic populations derived from NAM designs. This method is called joint inclusive composite interval mapping (JICIM). Simulations were designed on the detected QTL in a maize NAM population and an Arabidopsis NAM population so as to evaluate the efficiency of the NAM design and the JICIM method. PRINCIPAL FINDINGS: Fifty-two QTL were identified in the maize population, explaining 89% of the phenotypic variance of days to silking, and nine QTL were identified in the Arabidopsis population, explaining 83% of the phenotypic variance of flowering time. Simulations indicated that the detection power of these identified QTL was consistently high, especially for large-effect QTL. For rare QTL having significant effects in only one family, the power of correct detection within the 5 cM support interval was around 80% for 1-day effect QTL in the maize population, and for 3-day effect QTL in the Arabidopsis population. For smaller-effect QTL, the power diminished, e.g., it was around 50% for maize QTL with an effect of 0.5 day. When QTL were linked at a distance of 5 cM, the likelihood of mapping them as two distinct QTL was about 70% in the maize population. When the linkage distance was 1 cM, they were more likely mapped as one single QTL at an intermediary position. CONCLUSIONS: Because it takes advantage of the large genetic variation among parental lines and the large population size, NAM is a powerful multiple-cross design for complex trait dissection. JICIM is an efficient and specialty method for the joint QTL linkage mapping of genetic populations derived from the NAM design

    Early Left-Hemispheric Dysfunction of Face Processing in Congenital Prosopagnosia: An MEG Study

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    Electrophysiological research has demonstrated the relevance to face processing of a negative deflection peaking around 170 ms, labelled accordingly as N170 in the electroencephalogram (EEG) and M170 in magnetoencephalography (MEG). The M170 was shown to be sensitive to the inversion of faces and to familiarity-two factors that are assumed to be crucial for congenital prosopagnosia. In order to locate the cognitive dysfunction and its neural correlates, we investigated the time course of neural activity in response to these manipulations.Seven individuals with congenital prosopagnosia and seven matched controls participated in the experiment. To explore brain activity with high accuracy in time, we recorded evoked magnetic fields (275 channel whole head MEG) while participants were looking at faces differing in familiarity (famous vs. unknown) and orientation (upright vs. inverted). The underlying neural sources were estimated by means of the least square minimum-norm-estimation (L2-MNE) approach.The behavioural data corroborate earlier findings on impaired configural processing in congenital prosopagnosia. For the M170, the overall results replicated earlier findings, with larger occipito-temporal brain responses to inverted than upright faces, and more right- than left-hemispheric activity. Compared to controls, participants with congenital prosopagnosia displayed a general decrease in brain activity, primarily over left occipitotemporal areas. This attenuation did not interact with familiarity or orientation.The study substantiates the finding of an early involvement of the left hemisphere in symptoms of prosopagnosia. This might be related to an efficient and overused featural processing strategy which serves as a compensation of impaired configural processing

    Imageability ratings across languages

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    Imageability is a psycholinguistic variable that indicates how well a word gives rise to a mental image or sensory experience. Imageability ratings are used extensively in psycholinguistic, neuropsychological, and aphasiological studies. However, little formal knowledge exists about whether and how these ratings are associated between and within languages. Fifteen imageability databases were cross-correlated using nonparametric statistics. Some of these corresponded to unpublished data collected within a European research network-the Collaboration of Aphasia Trialists (COST IS1208). All but four of the correlations were significant. The average strength of the correlations (rho = .68) and the variance explained (R (2) = 46%) were moderate. This implies that factors other than imageability may explain 54% of the results. Imageability ratings often correlate across languages. Different possibly interacting factors may explain the moderate strength and variance explained in the correlations: (1) linguistic and cultural factors; (2) intrinsic differences between the databases; (3) range effects; (4) small numbers of words in each database, equivalent words, and participants; and (5) mean age of the participants. The results suggest that imageability ratings may be used cross-linguistically. However, further understanding of the factors explaining the variance in the correlations will be needed before research and practical recommendations can be made
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