81 research outputs found

    Bell's local causality is a d-separation criterion

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    This paper aims to motivate Bell's notion of local causality by means of Bayesian networks. In a locally causal theory any superluminal correlation should be screened off by atomic events localized in any so-called \textit{shielder-off region} in the past of one of the correlating events. In a Bayesian network any correlation between non-descendant random variables are screened off by any so-called \textit{d-separating set} of variables. We will argue that the shielder-off regions in the definition of local causality conform in a well defined sense to the d-separating sets in Bayesian networks.Comment: 13 pages, 8 figure

    Bell's local causality is a d-separation criterion

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    This paper aims to motivate Bell’s notion of local causality by means of Bayesian networks. In a locally causal theory any superluminal correlation should be screened off by atomic events localized in any so-called shielder-off region in the past of one of the correlating events. In a Bayesian network any correlation between non-descendant random variables are screened off by any so-called d-separating set of variables. We will argue that the shielder-off regions in the definition of local causality conform in a well defined sense to the d-separating sets in Bayesian networks

    Fumonisin B1 exposure increases Hsp70 expression in the lung and kidney of rats without inducing significant oxidative stress

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    The objective of this experiment was to determine whether fumonisin B1 (FB1) added to the diet of rats in a dose of 50 mg/kg changes the production of heat shock protein 70 (Hsp70) in the lungs and kidney of rats. We also studied the effect of this mycotoxin on the antioxidant system of the body. Mature (8 weeks old) male Wistar Crl:WI BR rats (n = 6/group) were fed the toxin-containing diet for 5 days. FB1 resulted in a 7% body weight reduction without significantly changing the feed intake. Western blot analysis of the lungs and kidney demonstrated a substantial (1.4-fold and 1.8-fold, respectively) increase in Hsp70 expression. Alterations could not be detected in the clinical chemical parameters (total protein, albumin, total cholesterol, glucose, creatinine and urea concentrations, and aspartate aminotransferase activity). There was no statistically significant change in malondialdehyde concentrations and the measured antioxidant parameters (the amount of reduced glutathione, GSH and glutathione peroxidase activity, GPx) in the blood plasma, lung and kidney tissue. Thus, it can be concluded that FB1 did not induce oxidative stress in the lungs and kidney, but increased Hsp70 production

    Remarks on Causality in Relativistic Quantum Field Theory

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    It is shown that the correlations predicted by relativistic quantum field theory in locally normal states between projections in local von Neumann algebras \cA(V_1),\cA(V_2) associated with spacelike separated spacetime regions V1,V2V_1,V_2 have a (Reichenbachian) common cause located in the union of the backward light cones of V1V_1 and V2V_2. Further comments on causality and independence in quantum field theory are made.Comment: 10 pages, Latex, Quantum Structures 2002 Conference Proceedings submission. Minor revision of the order of definitions on p.

    Analysis of Ionizing Radiation Induced DNA Damage by Superresolution dSTORM Microscopy

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    The quantitative detection of radiation caused DNA double-strand breaks (DSB) by immunostained γ-H2AX foci using direct stochastic optical reconstruction microscopy (dSTORM) provides a deeper insight into the DNA repair process at nanoscale in a time-dependent manner. Glioblastoma (U251) cells were irradiated with 250 keV X-ray at 0, 2, 5, 8 Gy dose levels. Cell cycle phase distribution and apoptosis of U251 cells upon irradiation was assayed by flow cytometry. We studied the density, topology and volume of the γ-H2AX foci with 3D confocal microscopy and the dSTORM superresolution method. A pronounced increase in γ-H2AX foci and cluster density was detected by 3D confocal microscopy after 2 Gy, at 30 min postirradiation, but both returned to the control level at 24 h. Meanwhile, at 24 h a considerable amount of residual foci could be measured from 5 Gy, which returned to the normal level 48 h later. The dSTORM based γ-H2AX analysis revealed that the micron-sized γ-H2AX foci are composed of distinct smaller units with a few tens of nanometers. The density of these clusters, the epitope number and the dynamics of γ-H2AX foci loss could be analyzed. Our findings suggest a discrete level of repair enzyme capacity and the restart of the repair process for the residual DSBs, even beyond 24 h. The dSTORM superresolution technique provides a higher precision over 3D confocal microscopy to study radiation induced γ-H2AX foci and molecular rearrangements during the repair process, opening a novel perspective for radiation research

    First-line therapy in atypical hemolytic uremic syndrome: consideration on infants with a poor prognosis.

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    BackgroundAtypical hemolytic uremic syndrome (aHUS) is a rare and heterogeneous disorder. The first line treatment of aHUS is plasma therapy, but in the past few years, the recommendations have changed greatly with the advent of eculizumab, a humanized monoclonal anti C5-antibody. Although recent recommendations suggest using it as a primary treatment for aHUS, important questions have arisen about the necessity of immediate use of eculizumab in all cases. We aimed to draw attention to a specific subgroup of aHUS patients with rapid disease progression and high mortality, in whom plasma therapy may not be feasible.MethodsWe present three pediatric patients of acute complement-mediated HUS with a fatal outcome. Classical and alternative complement pathway activity, levels of complement factors C3, C4, H, B and I, as well as of anti-factor H autoantibody and of ADAMTS13 activity were determined. The coding regions of CFH, CFI, CD46, THBD, CFB and C3 genes were sequenced and the copy number of CFI, CD46, CFH and related genes were analyzed.ResultsWe found severe activation and consumption of complement components in these patients, furthermore, in one patient we identified a previously not reported mutation in CFH (Ser722Stop), supporting the diagnosis of complement-mediated HUS. These patients were not responsive to the FFP therapy, and all cases had fatal outcome.ConclusionTaking the heterogeneity and the variable prognosis of atypical HUS into account, we suggest that the immediate use of eculizumab should be considered as first-line therapy in certain small children with complement dysregulation
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