2,822 research outputs found

    Bell Correlations and the Common Future

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    Reichenbach's principle states that in a causal structure, correlations of classical information can stem from a common cause in the common past or a direct influence from one of the events in correlation to the other. The difficulty of explaining Bell correlations through a mechanism in that spirit can be read as questioning either the principle or even its basis: causality. In the former case, the principle can be replaced by its quantum version, accepting as a common cause an entangled state, leaving the phenomenon as mysterious as ever on the classical level (on which, after all, it occurs). If, more radically, the causal structure is questioned in principle, closed space-time curves may become possible that, as is argued in the present note, can give rise to non-local correlations if to-be-correlated pieces of classical information meet in the common future --- which they need to if the correlation is to be detected in the first place. The result is a view resembling Brassard and Raymond-Robichaud's parallel-lives variant of Hermann's and Everett's relative-state formalism, avoiding "multiple realities."Comment: 8 pages, 5 figure

    SILAC-based proteomic quantification of chemoattractant-induced cytoskeleton dynamics on a second to minute timescale

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    Cytoskeletal dynamics during cell behaviours ranging from endocytosis and exocytosis to cell division and movement is controlled by a complex network of signalling pathways, the full details of which are as yet unresolved. Here we show that SILAC-based proteomic methods can be used to characterize the rapid chemoattractant-induced dynamic changes in the actin–myosin cytoskeleton and regulatory elements on a proteome-wide scale with a second to minute timescale resolution. This approach provides novel insights in the ensemble kinetics of key cytoskeletal constituents and association of known and novel identified binding proteins. We validate the proteomic data by detailed microscopy-based analysis of in vivo translocation dynamics for key signalling factors. This rapid large-scale proteomic approach may be applied to other situations where highly dynamic changes in complex cellular compartments are expected to play a key role

    Cross modal perception of body size in domestic dogs (Canis familiaris)

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    While the perception of size-related acoustic variation in animal vocalisations is well documented, little attention has been given to how this information might be integrated with corresponding visual information. Using a cross-modal design, we tested the ability of domestic dogs to match growls resynthesised to be typical of either a large or a small dog to size- matched models. Subjects looked at the size-matched model significantly more often and for a significantly longer duration than at the incorrect model, showing that they have the ability to relate information about body size from the acoustic domain to the appropriate visual category. Our study suggests that the perceptual and cognitive mechanisms at the basis of size assessment in mammals have a multisensory nature, and calls for further investigations of the multimodal processing of size information across animal species

    Quasi-Normal Modes of Stars and Black Holes

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    Perturbations of stars and black holes have been one of the main topics of relativistic astrophysics for the last few decades. They are of particular importance today, because of their relevance to gravitational wave astronomy. In this review we present the theory of quasi-normal modes of compact objects from both the mathematical and astrophysical points of view. The discussion includes perturbations of black holes (Schwarzschild, Reissner-Nordstr\"om, Kerr and Kerr-Newman) and relativistic stars (non-rotating and slowly-rotating). The properties of the various families of quasi-normal modes are described, and numerical techniques for calculating quasi-normal modes reviewed. The successes, as well as the limits, of perturbation theory are presented, and its role in the emerging era of numerical relativity and supercomputers is discussed.Comment: 74 pages, 7 figures, Review article for "Living Reviews in Relativity

    The impact of DMARD and anti-TNF therapy on functional characterization of short-term T-cell activation in patients with rheumatoid arthritis - A follow-up study

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    Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by a systemic dysfunction of T-cells. In this study we tested the impact of DMARD and anti-TNF agents on short-term activation characteristics of T-cells. We enrolled 12 patients with newly diagnosed RA (naïve RA) who were treated with methothrexate (MTX) and glucocorticsteroid (GCS) and 22 patients with established RA non responding to conventional DMARD therapy who were treated with different anti-TNF agents. Nine healthy volunteers served as controls. Blood samples were taken at baseline, then at 4th and 8th week of therapy. The characteristics of several intracellular activation processes during short-term activation of T-cells including cytoplasmic Ca2+ level, mitochondrial Ca2+ level, reactive oxygen species (ROS) and nitric oxide (NO) generation were determined by a novel flow-cytometry technique. At baseline, the tested processes were comparable to controls in naïve RA. During GCS therapy, cytoplasmic Ca2+ level and ROS generation decreased. After the addition of MTX to GCS cytoplasmic Ca2+ level became comparable to controls, while ROS generation decreased further. In DMARD non responders, cytoplasmic Ca2+ level was higher than controls at baseline. The cytoplasmic Ca2+ level became comparable to controls and ROS generation decreased during each of the three anti-TNF-α agent therapies. Mitochondrial Ca2+ level and NO generation were unaltered in all of the patient groups. These results indicate that intracellular machinery is affected in T-cells of RA patients. This may alter the behavior of T-cells during activation. Different therapeutic approaches may modulate the abnormal T-cell functions. © 2014 Szalay et al

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Obesity and pronated foot type may increase the risk of chronic plantar heel pain : a matched case-control study

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    Background : Chronic plantar heel pain (CPHP) is one of the most common musculoskeletal disorders of the foot, yet its aetiology is poorly understood. The purpose of this study was to examine the association between CPHP and a number of commonly hypothesised causative factors.Methods : Eighty participants with CPHP (33 males, 47 females, mean age 52.3 years, S.D. 11.7) were matched by age (&plusmn; 2 years) and sex to 80 control participants (33 males, 47 females, mean age 51.9 years, S.D. 11.8). The two groups were then compared on body mass index (BMI), foot posture as measured by the Foot Posture Index (FPI), ankle dorsiflexion range of motion (ROM) as measured by the Dorsiflexion Lunge Test, occupational lower limb stress using the Occupational Rating Scale and calf endurance using the Standing Heel Rise Test.Results : Univariate analysis demonstrated that the CPHP group had significantly greater BMI (29.8 &plusmn; 5.4 kg/m2 vs. 27.5 &plusmn; 4.9 kg/m2; P &lt; 0.01), a more pronated foot posture (FPI score 2.4 &plusmn; 3.3 vs. 1.1 &plusmn; 2.3; P &lt; 0.01) and greater ankle dorsiflexion ROM (45.1 &plusmn; 7.1&deg; vs. 40.5 &plusmn; 6.6&deg;; P &lt; 0.01) than the control group. No difference was identified between the groups for calf endurance or time spent sitting, standing, walking on uneven ground, squatting, climbing or lifting. Multivariate logistic regression revealed that those with CPHP were more likely to be obese (BMI &ge; 30 kg/m2) (OR 2.9, 95% CI 1.4 &ndash; 6.1, P &lt; 0.01) and to have a pronated foot posture (FPI &ge; 4) (OR 3.7, 95% CI 1.6 &ndash; 8.7, P &lt; 0.01).Conclusion : Obesity and pronated foot posture are associated with CPHP and may be risk factors for the development of the condition. Decreased ankle dorsiflexion, calf endurance and occupational lower limb stress may not play a role in CPHP.<br /
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