2,721 research outputs found

    Finite Volume Cumulant Expansion in QCD-Colorless Plasma

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    Due to the finite size effects, the localisation of the phase transition in finite systems and the determination of its order, become an extremely difficult task, even in the simplest known cases. In order to identify and locate the finite volume transition point T0(V)T_{0}(V) of the QCD deconfinement phase transition to a Colorless QGP, we have developed a new approach using the finite size cumulant expansion of the order parameter and the LmnL_{mn}-method. The first six cumulants C1,2,3,4,5,6C_{1,2,3,4,5,6} with the corresponding under-normalized ratios(skewness Σ\Sigma, kurtosis κ\kappa ,pentosis Π±\Pi_{\pm} and hexosis H1,2,3\mathcal{H}_{1,2,3}) and three unnormalized combinations of them (O=σ2κΣ1\mathcal{O}={\mathcal{\sigma }^{2} \mathcal{\kappa } }{\mathbf{\Sigma }^{-1} }, U=σ2Σ1\mathcal{U} ={\mathcal{\sigma }^{-2} \mathbf{\Sigma }^{-1} }, N=σ2κ\mathcal{N} = \mathcal{\sigma }^{2} \mathcal{\kappa }) are calculated and studied as functions of (T,V)(T,V). A new approach, unifying in a clear and consistent way the definitions of cumulant ratios, is proposed. A numerical FSS analysis of the obtained results has allowed us to locate accurately the finite volume transition point. The extracted transition temperature value T0(V)T_{0}(V) agrees with that expected T0N(V)T_{0}^{N}(V) from the order parameter and the thermal susceptibility χT(T,V)\chi _{T}\left( T,V\right), according to the standard procedure of localization to within about 2%2\%. In addition to this, a very good correlation factor is obtained proving the validity of our cumulants method. The agreement of our results with those obtained by means of other models is remarkable.Comment: 19 pages,14 figues, figures 4,5,6 figures are oversized, therefore, can be obtained directly from [email protected],Accepted for publication in EPJ

    Full Scale Proton Beam Impact Testing of new CERN Collimators and Validation of a Numerical Approach for Future Operation

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    New collimators are being produced at CERN in the framework of a large particle accelerator upgrade project to protect beam lines against stray particles. Their movable jaws hold low density absorbers with tight geometric requirements, while being able to withstand direct proton beam impacts. Such events induce considerable thermo-mechanical loads, leading to complex structural responses, which make the numerical analysis challenging. Hence, an experiment has been developed to validate the jaw design under representative conditions and to acquire online results to enhance the numerical models. Two jaws have been impacted by high-intensity proton beams in a dedicated facility at CERN and have recreated the worst possible scenario in future operation. The analysis of online results coupled to post-irradiation examinations have demonstrated that the jaw response remains in the elastic domain. However, they have also highlighted how sensitive the jaw geometry is to its mounting support inside the collimator. Proton beam impacts, as well as handling activities, may alter the jaw flatness tolerance value by ±\pm 70 μ{\mu}m, whereas the flatness tolerance requirement is 200 μ{\mu}m. In spite of having validated the jaw design for this application, the study points out numerical limitations caused by the difficulties in describing complex geometries and boundary conditions with such unprecedented requirements.Comment: 22 pages, 17 figures, Prepared for submission to JINS

    Why don't serum vitamin D concentrations associate with BMD by DXA? A case of being 'bound' to the wrong assay? Implications for vitamin D screening.

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    BACKGROUND: The association between bone mineral density (BMD) and serum25-hydroxyvitamin D (25(OH)D) concentration is weak, particularly in certain races (eg, BlackAfrican vs Caucasian) and in athletic populations. We aimed to examine if bioavailable vitamin D rather than serum 25(OH)D was related to markers of bone health within a racially diverse athletic population. METHODS: In 604 male athletes (Arab (n=327), Asian (n=48), Black(n=108), Caucasian (n=53)and Hispanic (n=68)), we measured total 25(OH)D, vitamin D-binding protein and BMD by DXA. Bioavailable vitamin D was calculated using the free hormone hypothesis. RESULTS: From 604 athletes, 21.5% (n=130) demonstrated severe 25(OH)D deficiency, 37.1% (n=224) deficiency, 26% (n=157) insufficiency and 15.4% (n=93) sufficiency. Serum 25(OH)D concentrations were not associated with BMD at any site. After adjusting for age and race, bioavailable vitamin D was associated with BMD (spine, neck and hip). Mean serum vitamin D binding protein concentrations were not associated with 25(OH)D concentrations (p=0.392). CONCLUSION: Regardless of age or race, bioavailable vitamin D and not serum 25(OH)D was associated with BMD in a racially diverse athletic population. If vitamin D screening is warranted, clinicians should use appropriate assays to calculate vitamin D binding protein and bioavailable vitamin D levels concentrations than serum 25(OH)D. In turn, prophylactic vitamin D supplementation to 'correct' insufficient athletes should not be based on serum 25(OH)D measures

    Tunis's New Mosques Constructed Between 1975 and 1995: Morphological Knowledge

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    The mosque has always been a prominent unit that used to structure the old Islamic cites. Its architecture through the Muslim world has always aroused the interest of many researchers. Actually, mosques are still built while undergoing the changes which occurred on the modern societies. However, only few research who have been interested in the new mosques. This paper targets the architecture of mosques built in Tunis governorate between 1975 and 1995. Through a morphological analysis of 24 mosques we were able to determine their identity and their morphological structure. According to their form and position, we discovered classes of specimen and classes of segments. Our corpus presents several constants and variations that we can explain though the introduction of some extrinsic attributes. In fact, these architectural objects possess some morphological specifications related to some urban, functional and historical factors

    Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method, applied in Risk-UE project

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11069-016-2566-8Al Hoceima is one of the most seismic active regions in north of Morocco. It is demonstrated by the large seismic episodes reported in seismic catalogs and research studies. However, seismic risk is relatively high due to vulnerable buildings that are either old or don’t respect seismic standards. Our aim is to present a study about seismic risk and seismic scenarios for the city of Al Hoceima. The seismic vulnerability of the existing residential buildings was evaluated using the vulnerability index method (Risk-UE). It was chosen to be adapted and applied to the Moroccan constructions for its practicality and simple methodology. A visual inspection of 1102 buildings was carried out to assess the vulnerability factors. As for seismic hazard, it was evaluated in terms of macroseismic intensity for two scenarios (a deterministic and probabilistic scenario). The maps of seismic risk are represented by direct damage on buildings, damage to population and economic cost. According to the results, the main vulnerability index of the city is equal to 0.49 and the seismic risk is estimated as Slight (main damage grade equal to 0.9 for the deterministic scenario and 0.7 for the probabilistic scenario). However, Moderate to heavy damage is expected in areas located in the newer extensions, in both the east and west of the city. Important economic losses and damage to the population are expected in these areas as well. The maps elaborated can be a potential guide to the decision making in the field of seismic risk prevention and mitigation strategies in Al Hoceima.Peer ReviewedPostprint (author's final draft

    Nonlinear optical properties of selected natural pigments extracted from spinach: Carotenoids

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    They are report here, for the first time in authors knowledge, results on third order nonlinear optical susceptibilities from a series of natural pigments extracted from spinach. The measurements were performed in-situ at 532 nm wavelength using degenerate four wave mixing technique (DFWM). For comparison third order nonlinear optical susceptibilities of the same pigments were also evaluated using third harmonic generation (THG) set up at 1064 nm. The electronic contribution to the observed properties was also deduced. The measurements were performed on thin films deposited on a thick glass substrate. These pigments were also identified by UV–VIS spectral analysis. All these results were in good agreement with the literature data

    Gamma-D crystallin gene (CRYGD) mutation causes autosomal dominant congenital cerulean cataracts

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    Congenital cataracts are a major cause of bilateral visual impairment in childhood. We mapped the gene responsible for autosomal congenital cerulean cataracts to chromosome 2q33-35 in a four generation family of Moroccan descent. The maximum lod score (7.19 at recombination fraction theta=0) was obtained for marker D2S2208 near the g-crystallin gene (CRYG) cluster. Sequencing of the coding regions of the CRYGA, B, C, and D genes showed the presence of a heterozygous C>A transversion in exon 2 of CRYGD that is associated with cataracts in this family. This mutation resulted in a proline to threonine substitution at amino acid 23 of the protein in the first of the four Greek key motifs that characterise this protein. We show that although the x ray crystallography modelling does not indicate any change of the backbone conformation, the mutation affects a region of the Greek key motif that is important for determining the topology of this protein fold. Our data suggest strongly that the proline to threonine substitution may alter the protein folding or decrease the thermodynamic stability or solubility of the protein. Furthermore, this is the first report of a mutation in this gene resulting in autosomal dominant congenital cerulean cataracts
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