313 research outputs found

    On the Consequences of Retaining the General Validity of Locality in Physical Theory

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    The empirical validity of the locality (LOC) principle of relativity is used to argue in favour of a local hidden variable theory (HVT) for individual quantum processes. It is shown that such a HVT may reproduce the statistical predictions of quantum mechanics (QM), provided the reproducibility of initial hidden variable states is limited. This means that in a HVT limits should be set to the validity of the notion of counterfactual definiteness (CFD). This is supported by the empirical evidence that past, present, and future are basically distinct. Our argumentation is contrasted with a recent one by Stapp resulting in the opposite conclusion, i.e. nonlocality or the existence of faster-than-light influences. We argue that Stapp's argumentation still depends in an implicit, but crucial, way on both the notions of hidden variables and of CFD. In addition, some implications of our results for the debate between Bohr and Einstein, Podolsky and Rosen are discussed.Comment: revtex, 11 page

    The prevalence of middle ear pathogens in the outer ear canal and the nasopharyngeal cavity of healthy young adults

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    AbstractCulturing middle ear fluid samples from children with chronic otitis media with effusion (OME) using standard techniques results in the isolation of bacterial species in approximately 30–50% of the cases. Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, the classic middle ear pathogens of acute otitis media, are involved but, recently, several studies suggested Alloiococcus otitidis as an additional pathogen. In the present study, we used species-specific PCRs to establish the prevalence, in both the nasopharyngeal cavity and the outer ear, of H. influenzae, M. catarrhalis, S. pneumoniae and A. otitidis. The study group consisted of 70 healthy volunteers (aged 19–22 years). The results indicate a high prevalence (>80%) of A. otitidis in the outer ear in contrast to its absence in the nasopharynx. H. influenzae was found in both the outer ear and the nasopharynx (6% and 14%, respectively), whereas S. pneumoniae and M. catarrhalis were found only in the nasopharynx (9% and 34%, respectively). A. otitidis, described as a fastidious organism, were able to be cultured using an optimized culture protocol, with prolonged incubation, which allowed the isolation of A. otitidis in five of the nine PCR-positive samples out of the total of ten samples tested. Given the absence of the outer ear inhabitant A. otitidis from the nasopharynx, its role in the aetiology of OME remains ambiguous because middle ear infecting organisms are considered to invade the middle ear from the nasopharynx through the Eustachian tube

    Design and prototype of a train-to-wayside communication architecture

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    Telecommunication has become very important in modern society and seems to be almost omnipresent, making daily life easier, more pleasant and connecting people everywhere. It does not only connect people, but also machines, enhancing the efficiency of automated tasks and monitoring automated processes. In this context the IBBT (Interdisciplinary Institute for BroadBand Technology) project TRACK (TRain Applications over an advanced Communication networK), sets the definition and prototyping of an end-to-end train-to-wayside communication architecture as one of the main research goals. The architecture provides networking capabilities for train monitoring, personnel applications and passenger Internet services. In the context of the project a prototype framework was developed to give a complete functioning demonstrator. Every aspect: tunneling and mobility, performance enhancements, and priority and quality of service were taken into consideration. In contrast to other research in this area, which has given mostly high-level overviews, TRACK resulted in a detailed architecture with all different elements present

    On the nonlinear evolution of the Poisson’s ratio under quasi-static loading for a carbon fabricreinforced thermoplastic, Part I:

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    a b s t r a c t When observing or describing the damage state in a composite material, often only Young's modulus or residual deformation are considered. Generally, however, the Poisson's ratio is more sensitive to damage than those properties. Rather than observing the Poisson's ratio as function of crack density, the evolution of the Poisson's ratio as function of the longitudinal strain was studied in part I of this research, where a peculiar shape of the evolution was observed and proven to be entirely due to the material itself, rather than the sensors used for the strain measurement. In this article, a theoretical explanation for the peculiar evolution of the Poisson's ratio as function of the longitudinal strain is presented. Based on this explanation, extra experiments were conducted for validation purposes. The material used for this study is a carbon fabric-reinforced PPS

    Local damage in a 5-harness satin weave composite under static tension, part I: experimental analysis

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    International audienceThis paper presents an experimental damage analysis of a 5-harness satin weave carbon-PPS (PolyPhenylene Sulphide) composite under uni-axial static tensile load. In order to understand the local damage behaviour, tensile tests were performed and accompanied by acoustic emission (AE) and microscopic analysis of the composite specimen. These tests enable us to detect the damage initiation stress as well as the damage initiation location in the composite. Microscopic observation of the tested composite laminates allowed the characterization of the sequence of intra-yarn transverse damage (perpendicular to the load direction) occurrence at different locations in the laminate, starting from crack initiation to the final failure of the composite

    In-situ local strain measurement in textile composites with embedded optical fibre sensors

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    To understand the local strains inside a textile composite, numerical simulations are typically done on the scale of one repetitive unit cell of the weaving pattern. Periodic boundary conditions are applied to the edges of the unit cell and different load cases can then be applied to the unit cell of the textile composite. Most often, the periodic boundary conditions are applied on all faces of the unit cell, which implies the assumption that the material is repeating itself over an infinite distance in all three orthogonal directions. This assumption is more or less valid for the textile composite material in the midplane of thick laminates, where it is constrained by neighbouring material in all three directions. It is very difficult to validate such simulations, because local strain measurements inside a textile composite have rarely been done, and the interpretation is not straightforward. This paper shows the successful use of embedded optical fibre sensors to measure the local strains inside a satin weave carbon/PPS composite (typically used in aerospace applications). The length of the Bragg grating inside the optical fibre sensor has been chosen such that it is longer than the length of one unit cell of the satin weave architecture (7.4 mm). The read-outs of the optical fibre sensor give the minimum and maximum local strains that occur along the length of the Bragg grating

    Ergogenic effect of pre-exercise chicken broth ingestion on a high-intensity cycling time-trial

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    Background: chicken meat extract is a popular functional food in Asia. It is rich in the bioactive compounds carnosine and anserine, two histidine-containing dipeptides (HCD). Studies suggest that acute pre-exercise ingestion of chicken extracts has important applications towards exercise performance and fatigue control, but the evidence is equivocal. This study aimed to evaluate the ergogenic potential of the pre-exercise ingestion of a homemade chicken broth (CB) vs a placebo soup on a short-lasting, high-intensity cycling exercise. Methods: fourteen men participated in this double-blind, placebo-controlled, crossover intervention study. Subjects ingested either CB, thereby receiving 46.4 mg/kg body weight of HCD, or a placebo soup (similar in taste without HCD) 40 min before an 8 min cycling time trial (TT) was performed. Venous blood samples were collected at arrival (fasted), before exercise and at 5 min recovery. Plasma HCD were measured with UPLC-MS/MS and glutathione (in red blood cells) was measured through HPLC. Capillary blood samples were collected at different timepoints before and after exercise. Results: a significant improvement (p = 0.033; 5.2%) of the 8 min TT mean power was observed after CB supplementation compared to placebo. Post-exercise plasma carnosine (p <  0.05) and anserine (p <  0.001) was significantly increased after CB supplementation and not following placebo. No significant effect of CB supplementation was observed either on blood glutathione levels, nor on capillary blood analysis. Conclusions: oral CB supplementation improved the 8 min TT performance albeit it did not affect the acid-base balance or oxidative status parameters. Further research should unravel the potential role and mechanisms of HCD, present in CB, in this ergogenic approach

    Polar zipper sequence in the high-affinity hemoglobin of Ascaris suum: amino acid sequence and structural interpretation.

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    The extracellular hemoglobin of Ascaris has an extremely high oxygen affinity (P50 = 0.004 mmHg). It consists of eight identical subunits of molecular weight 40,600. Their sequence, determined by protein chemistry, shows two tandemly linked globin-like sequences and an 18-residue C-terminal extension. Two N-linked glycosylation sites contain equal ratios of mannose/glucosamine/fucose of 3:2:1. Electron micrographs suggest that the eight subunits form a polyhedron of point symmetry D4, or 42. The C-terminal extension contains a repeat of the sequence Glu-Glu-His-Lys, which would form a pattern of alternate glutamate and histidine side chains on one side and of glutamate and lysine side chains on the other side of a beta strand. We propose that this represents a polar zipper sequence and that the C-terminal extensions are joined in an eight-stranded beta barrel at the center of the molecule, with histidine and glutamate side chains inside and lysine and glutamate side chains outside the barrel compensating each other's charges. The amino acid sequence of Ascaris hemoglobin fails to explain its high oxygen affinity
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