535 research outputs found
Torsion cycles as non-local magnetic sources in non-orientable spaces
Non-orientable spaces can appear to carry net magnetic charge, even in the
absence of magnetic sources. It is shown that this effect can be understood as
a physical manifestation of the existence of torsion cycles of codimension one
in the homology of space.Comment: 17 pages, 4 figure
Effects of nanoparticles on murine macrophages
Metallic nanoparticles are more and more widely used in an increasing number
of applications. Consequently, they are more and more present in the
environment, and the risk that they may represent for human health must be
evaluated. This requires to increase our knowledge of the cellular responses to
nanoparticles. In this context, macrophages appear as an attractive system.
They play a major role in eliminating foreign matter, e.g. pathogens or
infectious agents, by phagocytosis and inflammatory responses, and are thus
highly likely to react to nanoparticles. We have decided to study their
responses to nanoparticles by a combination of classical and wide-scope
approaches such as proteomics. The long term goal of this study is the better
understanding of the responses of macrophages to nanoparticles, and thus to
help to assess their possible impact on human health. We chose as a model
system bone marrow-derived macrophages and studied the effect of commonly used
nanoparticles such as TiO2 and Cu. Classical responses of macrophage were
characterized and proteomic approaches based on 2D gels of whole cell extracts
were used. Preliminary proteomic data resulting from whole cell extracts showed
different effects for TiO2-NPs and Cu-NPs. Modifications of the expression of
several proteins involved in different pathways such as, for example, signal
transduction, endosome-lysosome pathway, Krebs cycle, oxidative stress response
have been underscored. These first results validate our proteomics approach and
open a new wide field of investigation for NPs impact on macrophagesComment: Nanosafe2010: International Conference on Safe Production and Use of
Nanomaterials 16-18 November 2010, Grenoble, France, Grenoble : France (2010
Charges and fluxes in Maxwell theory on compact manifolds with boundary
We investigate the charges and fluxes that can occur in higher-order Abelian
gauge theories defined on compact space-time manifolds with boundary. The
boundary is necessary to supply a destination to the electric lines of force
emanating from brane sources, thus allowing non-zero net electric charges, but
it also introduces new types of electric and magnetic flux. The resulting
structure of currents, charges, and fluxes is studied and expressed in the
language of relative homology and de Rham cohomology and the corresponding
abelian groups. These can be organised in terms of a pair of exact sequences
related by the Poincar\'e-Lefschetz isomorphism and by a weaker flip symmetry
exchanging the ends of the sequences. It is shown how all this structure is
brought into play by the imposition of the appropriately generalised Maxwell's
equations. The requirement that these equations be integrable restricts the
world-volume of a permitted brane (assumed closed) to be homologous to a cycle
on the boundary of space-time. All electric charges and magnetic fluxes are
quantised and satisfy the Dirac quantisation condition. But through some
boundary cycles there may be unquantised electric fluxes associated with
quantised magnetic fluxes and so dyonic in nature.Comment: 28 pages, plain Te
The Halo Mass of Optically Luminous Quasars at z ,Fâ ,F1-2 Measured via Gravitational Deflection of the Cosmic Microwave Background
© 2019. The American Astronomical Society. All rights reserved.We measure the average deflection of cosmic microwave background photons by quasars at ăZă= 1.7. Our sample is selected from the Sloan Digital Sky Survey to cover the redshift range 0.9 â€zâ€2.2 with absolute i-band magnitudes of M i â€-24 (K-corrected to z = 2). A stack of nearly 200,000 targets reveals an 8ÎŽ detection of Planck's estimate of the lensing convergence toward the quasars. We fit the signal with a model comprising a Navarro-Frenk-White density profile and a two-halo term accounting for correlated large-scale structure, which dominates the observed signal. The best-fitting model is described by an average halo mass log 10 (M h h -1 M)12.6 ±0.2 = and linear bias b=2.7±0.3 at ăZ ă= 1.7, in excellent agreement with clustering studies. We also report a hint, at a 90% confidence level, of a correlation between the convergence amplitude and luminosity, indicating that quasars brighter than MiâČ -26 reside in halos of typical mass M h â 10 13 h -1 M, scaling roughly as M h â L opt 3/4 at M i âČ-24 mag, in good agreement with physically motivated quasar demography models. Although we acknowledge that this luminosity dependence is a marginal result, the observed Mh-L opt relationship could be interpreted as a reflection of the cutoff in the distribution of black hole accretion rates toward high Eddington ratios: the weak trend of Mh with Lopt observed at low luminosity becomes stronger for the most powerful quasars, which tend to be accreting close to the Eddington limit.Peer reviewedFinal Accepted Versio
Prenatal and perinatal risk factors for eating disorders in women: A population cohort study
Objective: The fetal programming model hypothesizes that developmental programming in utero and in early life induces adaptations that predetermine the adult phenotype. This study investigated whether prenatal/perinatal complications are associated with lifetime eating disorders in women. Method: Participants included 46,373 adult women enrolled in the Norwegian Mother and Child Cohort Study (den norske Mor & barn-undersĂžkelsen [MoBa]). MoBa mothers and their mothers (MoBa grandmothers) were the focus of the current study. MoBa mothers with lifetime eating disorders were compared to a referent group. Results: MoBa mothers who weighed more at birth (birth weight, adjusted odds ratio [OR] = 1.14; 95% confidence interval [CI]: 1.10â1.19) or were born large-for-gestational-age (adjusted OR = 1.39; 95% CI: 1.27â1.52) were more likely to develop binge-eating disorder in later life. MoBa mothers who weighed less at birth were more likely to develop anorexia nervosa (birth weight, adjusted OR = 0.88; 95% CI: 0.81â0.95). Bulimia nervosa and purging disorder (PD) were not significantly predicted by the prenatal and perinatal factors examined. Discussion: Results of this study, which include the first known investigation of prenatal and perinatal factors in binge-eating disorder and PD, suggest that fetal programming may be relevant to the development of anorexia nervosa and binge-eating disorder. Future genetically informative research is needed to help disentangle whether these associations are a function of genetic influences or a true environmental fetal programming effect
Polo-like kinase 3 regulates CtIP during DNA double-strand break repair in G1
DNA double-strand breaks (DSBs) are repaired by nonhomologous end joining (NHEJ) or homologous recombination (HR). The C terminal binding proteinâinteracting protein (CtIP) is phosphorylated in G2 by cyclin-dependent kinases to initiate resection and promote HR. CtIP also exerts functions during NHEJ, although the mechanism phosphorylating CtIP in G1 is unknown. In this paper, we identify Plk3 (Polo-like kinase 3) as a novel DSB response factor that phosphorylates CtIP in G1 in a damage-inducible manner and impacts on various cellular processes in G1. First, Plk3 and CtIP enhance the formation of ionizing radiation-induced translocations; second, they promote large-scale genomic deletions from restriction enzyme-induced DSBs; third, they are required for resection and repair of complex DSBs; and finally, they regulate alternative NHEJ processes in Kuâ/â mutants. We show that mutating CtIP at S327 or T847 to nonphosphorylatable alanine phenocopies Plk3 or CtIP loss. Plk3 binds to CtIP phosphorylated at S327 via its Polo box domains, which is necessary for robust damage-induced CtIP phosphorylation at S327 and subsequent CtIP phosphorylation at T847
Dynamical Boson Stars
The idea of stable, localized bundles of energy has strong appeal as a model
for particles. In the 1950s John Wheeler envisioned such bundles as smooth
configurations of electromagnetic energy that he called {\em geons}, but none
were found. Instead, particle-like solutions were found in the late 1960s with
the addition of a scalar field, and these were given the name {\em boson
stars}. Since then, boson stars find use in a wide variety of models as sources
of dark matter, as black hole mimickers, in simple models of binary systems,
and as a tool in finding black holes in higher dimensions with only a single
killing vector. We discuss important varieties of boson stars, their dynamic
properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in
Relativity; major revision in 201
Macro-financial linkages and bank behaviour: evidence from the second-round effects of the global financial crisis on East Asia
This paper studies the link between macro-financial variability and bank behaviour, which justifies the second-round effects of the global financial crisis on East Asia. Following Gallego et al. (The impact of the global economic and financial crisis on Central Eastern and South Eastern Europe (CESEE) and Latin America, 2010), the second round effects are defined as the adverse feedback loop from the slumps in economic activities and sharp financial market deterioration, which may influence the financial performance of bank, inter alia via deteriorating credit quality, declining profitability and increasing problems in retaining necessary capitalization. Differentiating itself from other research, this study stresses adjustments in four dimensions of bank performance and behaviour: asset quality, profitability, capital adequacy, and lending behaviour, assuming that any change in a bank-specific characteristic is induced by endogenous adjustments of the others. The empirical results based on partial adjustment models and two-step system GMM estimation show that bankâs adjustment behaviour is subject to the variation in the macro-financial environment and the stress condition in the global financial market. There is no convincing evidence to support the effectiveness of policy rate cut to boots bank lending and to avoid a financial accelerator effect
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