503 research outputs found

    Berry-Esseen type bounds for the Left Random Walk on GL d (R) under polynomial moment conditions

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    Let An=εnε1A_n= \varepsilon_n \cdots \varepsilon_1, where (εn)n1(\varepsilon_n)_{n \geq 1} is a sequence of independent random matrices taking values in GLd(R) GL_d(\mathbb R), d2d \geq 2, with common distribution μ\mu. In this paper, under standard assumptions on μ\mu (strong irreducibility and proximality), we prove Berry-Esseen type theorems for log(An)\log ( \Vert A_n \Vert) when μ\mu has a polynomial moment. More precisely, we get the rate ((logn)/n)q/21((\log n) / n)^{q/2-1} when μ\mu has a moment of order q]2,3]q \in ]2,3] and the rate 1/n1/ \sqrt{n} when μ\mu has a moment of order 44, which significantly improves earlier results in this setting

    Rates in almost sure invariance principle for nonuniformly hyperbolic maps

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    We prove the Almost Sure Invariance Principle (ASIP) with close to optimal error rates for nonuniformly hyperbolic maps. We do not assume exponential contraction along stable leaves, therefore our result covers in particular slowly mixing invertible dynamical systems as Bunimovich flowers, billiards with flat points as in Chernov and Zhang (2005) and Wojtkowski' (1990) system of two falling balls. For these examples, the ASIP is a new result, not covered by prior works for various reasons, notably because in absence of exponential contraction along stable leaves, it is challenging to employ the so-called Sinai's trick (Sinai 1972, Bowen 1975) of reducing a nonuniformly hyperbolic system to a nonuniformly expanding one. Our strategy follows our previous papers on the ASIP for nonuniformly expanding maps, where we build a semiconjugacy to a specific renewal Markov shift and adapt the argument of Berkes, Liu and Wu (2014). The main difference is that now the Markov shift is two-sided, the observables depend on the full trajectory, both the future and the past

    DNA amplifications at 20q13 and MDM2 define distinct subsets of evolved breast and ovarian tumours.

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    DNA amplification seems to be particularly frequent in human breast tumours and has been associated with cancer evolution and aggressiveness. Recent data indicate that new events should be added to the list, such as the amplifications at chromosome 20q13 or the MDM2 gene. The present work aimed at determining the incidence and clinicopathological signification of these amplifications in a large series of breast and ovarian tumours. We tested 1371 breast and 179 ovarian tumours by Southern blotting and observed amplification of 20q13 in 5.4% breast and 2.8% ovarian carcinomas, whereas MDM2 was found amplified in 5.3% and 3.8% of breast and ovarian tumours respectively. MDM2 RNA expression levels were analysed in a subset of 57 breast tumours and overexpression was observed in 4/57 (7%) of the tumours. Elevated expression levels coincided with amplification of the gene. In breast cancer, 20q13 and MDM2 amplifications seem to define subsets of aggressive tumours. Indeed, 20q13 was correlated to axillary nodal involvement and occurred preferentially in younger patients (< 50 years). Furthermore, 20q13 correlated, as did MDM2 amplification, to aneuploidy. In parallel, we had also tested our tumour DNAs for amplification of CCND1, ERBB-2 and MYC, which made it possible to test for correlations with 20q13 or MDM2 amplifications. Whereas 20q13 showed a very strong correlation to CCND1 amplification, that of MDM2 was prevalent in MYC-amplified tumours. Interestingly, 20q13 and MDM2 amplifications showed some degree of correlation to each other, which may possibly be owing to the fact that both events occurred preferentially in aneuploid tumours. In ovarian cancer, no statistically significant correlation was observed. However, 20q13 amplification occurred preferentially in stage 3 tumours and MDM2 was correlated to ERBB-2 amplification. This may suggest that in ovarian tumours also, 20q13 and MDM2 amplifications occur in late or aggressive cancers

    Managing housing needs in post conflict housing reconstruction in Sri Lanka: gaps versus recommendations

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    Addressing housing needs in post conflict housing reconstruction leads to successful housing reconstruction. As part of a study of investigating how the housing needs can be effectively addressed in post conflict housing reconstruction, this paper identifies the gaps in managing housing needs in post conflict housing reconstruction within the context of Sri Lanka and presents the recommendations to minimise such gaps. Data was collected through un-structured interviews conducted with 37 participants, comprising policy makers, practitioners, academics and beneficiaries who engaged in post conflict housing reconstruction in Sri Lanka. Gaps were mainly found in conflict sensitivity, measures related to physical housing, performance of implementing agencies, policy and practice issues. On the job training, application of ‘do no harm’ principles, enhanced beneficiary participation, enhanced accountability, effective monitoring, enhanced knowledge sharing, adequate drinking water facilities, irrigation development and initiatives for material manufacturing were suggested as recommendations to minimise these gaps. Identification of gaps in managing housing needs in post conflict housing reconstruction and recommendations to minimise them inform policy makers to address the housing needs effectively through incorporating these aspects into the related policies. This in turn enhances the sustainability in housing development after conflicts

    Imaging Oxygen Distribution in Marine Sediments. The Importance of Bioturbation and Sediment Heterogeneity

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    The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns:the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowing species which does not build any structure. Oxygen two-dimensional distribution in sediments was quantified by means of the optical planar optode technique. Diffusive oxygen fluxes (mean and integrated) and a variability index were calculated on the captured oxygen images. All species increased sediment oxygen heterogeneity compared to the controls without animals. This was particularly noticeable with the polychaetes because of the construction of more or less complex burrows. Integrated diffusive oxygen flux increased with oxygen heterogeneity due to the production of interface available for solute exchanges between overlying water and sediments. This work shows that sediment heterogeneity is an important feature of the control of oxygen exchanges at the sediment–water interface

    Transmission of highly virulent community-associated MRSA ST93 and livestock-associated MRSA ST398 between humans and pigs in Australia

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    Pigs have been recognised as a reservoir of livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in Europe, Asia and North America. However, little is known about the presence and distribution of MRSA in the Australian pig population and pig industry. This study describes the presence, distribution and molecular characteristics of the human adapted Australian CA-MRSA ST93 isolated from pigs, people, and the environment within a piggery. Isolates were subjected to antibiotic susceptibility testing, DNA microarray, whole genome sequencing, multi locus sequence typing, virulence and resistance gene characterization and phylogenetic analysis. MRSA were isolated from 60% (n = 52) of farm workers where 84% of isolates returned ST93 and the rest ST398. Of the thirty-one pig isolates tested further, an equal number of ST398 and ST93 (15 each) and one as ST30-V were identified. Four of six environmental isolates were identified as ST93 and two as ST398. This study has identified for the first time in Australia the occurrence of CA-MRSA ST93 and LA-MRSA ST398 amongst farm workers, pigs, and the farm environment. Comparative genome analysis indicates that ST398 is likely to have been introduced into Australia from Europe or North America. This study also reports the first linezolid resistant MRSA isolated in Australia

    Nasal Colonization of Humans with Methicillin-Resistant Staphylococcus aureus (MRSA) CC398 with and without Exposure to Pigs

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    Background: Studies in several European countries and in North America revealed a frequent nasal colonization of livestock with MRSA CC398 and also in humans with direct professional exposure to colonized animals. The study presented here addresses the question of further transmission to non exposed humans. Methods: After selecting 47 farms with colonized pigs in different regions of Germany we sampled the nares of 113 humans working daily with pigs and of their 116 non exposed family members. The same was performed in 18 veterinarians attending pig farms and in 44 of their non exposed family members. For investigating transmission beyond families we samples the nares of 462 pupils attending a secondary school in a high density pig farming area. MRSA were detected by direct culture on selective agar. The isolates were typed by means of spa-sequence typing and classification of SCCmec elements. For attribution of spa sequence types to clonal lineages as defined by multi locus sequence typing we used the BURP algorithm. Antibiotic susceptibility testing was performed by microbroth dilution assay. Results: At the farms investigated 86% of humans exposed and only 4.3% of their family members were found to carry MRSA exhibiting spa-types corresponding to clonal complex CC398. Nasal colonization was also found in 45% of veterinarians caring for pig farms and in 9% of their non exposed family members. Multivariate analysis revealed that antibiotic usage prior to sampling beard no risk with respect to colonization. From 462 pupils only 3 were found colonized, all 3 were living on pig farms. Conclusion: These results indicate that so far the dissemination of MRSA CC398 to non exposed humans is infrequent and probably does not reach beyond familial communities

    Pharmacologic inhibition of the anaphase-promoting complex induces a spindle checkpoint-dependent mitotic arrest in the absence of spindle damage

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    Microtubule inhibitors are important cancer drugs that induce mitotic arrest by activating the spindle assembly checkpoint (SAC), which, in turn, inhibits the ubiquitin ligase activity of the anaphase-promoting complex (APC). Here, we report a small molecule, tosyl-L-arginine methyl ester (TAME), which binds to the APC and prevents its activation by Cdc20 and Cdh1. A prodrug of TAME arrests cells in metaphase without perturbing the spindle, but nonetheless the arrest is dependent on the SAC. Metaphase arrest induced by a proteasome inhibitor is also SAC dependent, suggesting that APC-dependent proteolysis is required to inactivate the SAC. We propose that mutual antagonism between the APC and the SAC yields a positive feedback loop that amplifies the ability of TAME to induce mitotic arrest
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