690 research outputs found
Berry-Esseen type bounds for the Left Random Walk on GL d (R) under polynomial moment conditions
Let , where is a sequence of independent random matrices taking values in , , with common distribution . In this paper,
under standard assumptions on (strong irreducibility and proximality), we
prove Berry-Esseen type theorems for when has a
polynomial moment. More precisely, we get the rate
when has a moment of order and the rate when
has a moment of order , which significantly improves earlier results
in this setting
Rates in almost sure invariance principle for nonuniformly hyperbolic maps
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
The Early Iron Age collective tomb LCG-1 at Dibba al-Bayah, Oman: long-distance exchange and cross-cultural interaction
The Iron Age (c. 1300-600 BC) of South-eastern Arabia is characterised by rapid expansion of settlement. Social structures formed over the previous millennia, however, persisted and were reinforced through the development of collective funerary monuments. A recently discovered tomb of Late Bronze to Early Iron Age date at Dibba al-Bayah in the Sultanate of Oman has yielded a range of artefacts that illuminate the nature and extent of the long-distance contacts of the local community. Seemingly selected not only for their exotic appeal, but also for their apotropaic function, these objects testify to a deep cross-cultural knowledge extending across the wider region during this crucial period in Arabian prehistory
A conjugate gradient method for the solution of the non-LTE line radiation transfer problem
This study concerns the fast and accurate solution of the line radiation
transfer problem, under non-LTE conditions. We propose and evaluate an
alternative iterative scheme to the classical ALI-Jacobi method, and to the
more recently proposed Gauss-Seidel and Successive Over-Relaxation (GS/SOR)
schemes. Our study is indeed based on the application of a preconditioned
bi-conjugate gradient method (BiCG-P). Standard tests, in 1D plane parallel
geometry and in the frame of the two-level atom model, with monochromatic
scattering, are discussed. Rates of convergence between the previously
mentioned iterative schemes are compared, as well as their respective timing
properties. The smoothing capability of the BiCG-P method is also demonstrated.Comment: Research note: 4 pages, 5 figures, accepted to A&
Міхал Бобжинський: суспільно-політична діяльність
Розглянута суспільно-політична діяльність визначного представника краківської
історичної школи М. Бобжинського. Акцентовано увагу на зв’язку наукових поглядів
історика з його політичною практикою. Охарактеризовано дискусії, які досьогодні
точаться серед науковців щодо оцінки результатів його діяльності.Рассмотрена общественно-политическая деятельность выдающегося представителя краковской исторической школы М. Бобжинского. Акцентировано внимание на связи научных взглядов историка с его политической практикой. Охарактеризованы дискуссии, которые досегодня ведутся среди ученых относительно оценки результатов его деятельности.The socio-political activities of M. Bobzhynski – a prominent representative of the Krakow
historical school – are reviewed. Attention is given to the connection of the historian scholarly
views with his political practice. The discussions that until now are going on among scholars
in evaluating the results of his work are characterised
Photoinduced ligand exchange dynamics of a polypyridyl ruthenium complex in aqueous solution
The understanding of photoinduced ligand exchange mechanisms in polypyridyl ruthenium(II) complexes operating in aqueous solution is of crucial importance to rationalize their photoreactivity. Herein, we demonstrate that a synergetic use of ab initio molecular dynamics simulations and static calculations, both conducted at the DFT level, can provide a full understanding of photosubstitution mechanisms of a monodentate ligand by a solvent water molecule in archetypal ruthenium complexes in explicit water. The simulations show that the photoinduced loss of a monodentate ligand generates an unreactive 16-electron species in a hitherto undescribed pentacoordinated triplet excited state that converts, via an easily accessible crossing point, to a reactive 16-electron singlet ground state, which combines with a solvent water molecule to yield the experimentally observed aqua complex in less than 10 ps. This work paves the way for the rational design of novel photoactive metal complexes relevant for biological applications.Metals in Catalysis, Biomimetics & Inorganic Material
DNA amplifications at 20q13 and MDM2 define distinct subsets of evolved breast and ovarian tumours.
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
Imaging Oxygen Distribution in Marine Sediments. The Importance of Bioturbation and Sediment Heterogeneity
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
Managing housing needs in post conflict housing reconstruction in Sri Lanka: gaps versus recommendations
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
In Vivo and In Vitro Pharmacological Studies of Methoxycarbonyl-Carboetomidate
Background—We previously developed two etomidate analogs that retain etomidate’s favorable hemodynamic properties, but whose adrenocortical effects are reduced in duration or magnitude. Methoxycarbonyl-etomidate (MOC-etomidate) is rapidly metabolized and ultra-short acting whereas (R)-ethyl 1-(1-phenylethyl)-1H-pyrrole-2-carboxylate (carboetomidate) does not potently inhibit 11?-hydroxylase. We hypothesized that MOC-etomidate’s labile ester could be incorporated into carboetomidate to produce a new agent that possesses favorable properties individually found in each agent. We describe the synthesis and pharmacology of methoxycarbonyl-(R)-ethyl 1-(1-phenylethyl)-1H-pyrrole-2-carboxylate (MOC-carboetomidate), a “soft” analog of carboetomidate. Methods—MOC-carboetomidate’s octanol:water partition coefficient was determined chromatographically and compared with those of etomidate, carboetomidate, and MOC-etomidate. MOC-carboetomidate’s EC50 and ED50 for loss of righting reflexes (LORR) were measured in tadpoles and rats, respectively. Its effect on gamma-aminobutyric acid A (GABAA) receptor function was assessed using two-microelectrode voltage clamp electrophysiological techniques and its metabolic stability was determined in pooled rat blood using high performance liquid chromatography. Its duration of action and effects on arterial blood pressure and adrenocortical function were assessed in rats. Results—MOC-carboetomidate’s octanol:water partition coefficient was 3300 ± 280, whereas those for etomidate, carboetomidate, and MOC-etomidate were 800 ± 180, 15000 ± 3700, and 190 ± 25, respectively. MOC-carboetomidate’s EC50 for LORR in tadpoles was 9 ± 1 µM and its EC50 for LORR in rats was 13 ± 5 mg/kg. At 13 µM, MOC-carboetomidate enhanced GABAA receptor currents by 400 ± 100%. Its metabolic half-life in pooled rat blood was 1.3 minutes. The slope of a plot of the duration of LORR in rats versus the logarithm of the hypnotic dose was significantly shallower for MOC-carboetomidate than for carboetomidate (4 ± 1 vs. 15 ± 3, respectively; p = 0. 0004123). At hypnotic doses, the effects of MOC-carboetomidate on arterial blood pressure and adrenocortical function were not significantly different from those of vehicle alone. Conclusions—MOC-carboetomidate is a GABAA receptor modulator with potent hypnotic activity that is more rapidly metabolized and cleared from the brain than carboetomidate, maintains hemodynamic stability similar to carboetomidate, and does not suppress adrenocortical function
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