1,041 research outputs found

    Garside and quadratic normalisation: a survey

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    Starting from the seminal example of the greedy normal norm in braid monoids, we analyse the mechanism of the normal form in a Garside monoid and explain how it extends to the more general framework of Garside families. Extending the viewpoint even more, we then consider general quadratic normalisation procedures and characterise Garside normalisation among them.Comment: 30 page

    Production of Biodiesel from Locally Available Spent Vegetable Oils

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    The depletion of fossil fuels prompted considerable research to find alternative fuels. Due its environmental benefits and renewable nature the production of biodiesel has acquired increasing importance with a view to optimizing the production procedure and the sources of feedstock. Millions of liters of waste frying oil are produced from local restaurants and houses every year, most are discarded into sewage systems causing damage to the networks.  This study is intended to consider aspects related to the feasibility of the production of biodiesel from waste frying oils which will solve the problem of waste frying oil pollution and reduce the cost of biodiesel production.This research studies the conversion of locally available spent vegetable oils of different origins and with different chemical compositions into an environmentally friendly fuel. The biodiesel production requirements by base catalyzed trans-esterification process for the different feed stocks are determined according to the measured physical properties. The quality of the produced biodiesel is compared to petro diesel in terms of established standard specifications

    DNA copy number changes in young gastric cancer patients with special reference to chromosome 19

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    Only a few cytogenetic and genetic studies have been performed in gastric cancer patients in young age groups. In the present study we used the comparative genomic hybridisation (CGH) method to characterise frequent DNA copy number changes in 22 gastric cancer patients of 45 years or younger and three gastric cancer cell lines established from patients younger than 45 years. Analysis of DNA copy number changes revealed frequent DNA copy number increases at chromosomes 17q (52%), 19q (68%) and 20q (64%). To confirm the CGH results and to characterise the amplicon region on the most frequently amplified chromosome, chromosome 19, we carried out fluorescence in situ hybridisation (FISH) analysis and Southern blot analysis. Fluorescence in situ hybridisation with the bacterial artificial chromosome (BAC) clone mapped to 19q12 indicated a copy number increase in all eight tumour specimens studied. Southern blot analysis of six tumour specimens and three tumour cell lines, with five probes mapped to the 19q12-13.2 region, suggested cyclin E to be one of the candidate target genes in the 19q region for gastric cancer tumorigenesis. Cyclin E protein overexpression was verified in tumours with amplification on chromosome 19. Further studies are required to investigate the biological and clinical significance of 19q amplicon and cyclin E upregulation in gastric cancer of young patient

    Chromosomal aberrations in benign and malignant Bilharzia-associated bladder lesions analyzed by comparative genomic hybridization

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    BACKGROUND: Bilharzia-associated bladder cancer (BAC) is a major health problem in countries where urinary schistosomiasis is endemic. Characterization of the genetic alterations in this cancer might enhance our understanding of the pathogenic mechanisms of the disease but, in contrast to nonbilharzia bladder cancer, BAC has rarely been the object of such scrutiny. In the present study, we aimed to characterize chromosomal imbalances in benign and malignant post-bilharzial lesions, and to determine whether their unique etiology yields a distinct cytogenetic profile as compared to chemically induced bladder tumors. METHODS: DNAs from 20 archival paraffin-embedded post-bilharzial bladder lesions (6 benign and 14 malignant) obtained from Sudanese patients (12 males and 8 females) with a history of urinary bilharziasis were investigated for chromosomal imbalances using comparative genomic hybridization (CGH). Subsequent FISH analysis with pericentromeric probes was performed on paraffin sections of the same cases to confirm the CGH results. RESULTS: Seven of the 20 lesions (6 carcinomas and one granuloma) showed chromosomal imbalances varying from 1 to 6 changes. The most common chromosomal imbalances detected were losses of 1p21-31, 8p21-pter, and 9p and gain of 19p material, seen in three cases each, including the benign lesion. CONCLUSION: Most of the detected imbalances have been repeatedly reported in non-bilharzial bladder carcinomas, suggesting that the cytogenetic profiles of chemical- and bilharzia-induced carcinomas are largely similar. However, loss of 9p seems to be more ubiquitous in BAC than in bladder cancer in industrialized countries

    Observation of two new Ξb−\Xi_b^- baryon resonances

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    Two structures are observed close to the kinematic threshold in the Ξb0π−\Xi_b^0 \pi^- mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1^{-1} recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content bdsbds are expected in this mass region: the spin-parity JP=12+J^P = \frac{1}{2}^+ and JP=32+J^P=\frac{3}{2}^+ states, denoted Ξbâ€Č−\Xi_b^{\prime -} and Ξb∗−\Xi_b^{*-}. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be m(Ξbâ€Č−)−m(Ξb0)−m(π−)=3.653±0.018±0.006m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006 MeV/c2/c^2, m(Ξb∗−)−m(Ξb0)−m(π−)=23.96±0.12±0.06m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06 MeV/c2/c^2, Γ(Ξb∗−)=1.65±0.31±0.10\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10 MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of Γ(Ξbâ€Č−)<0.08\Gamma(\Xi_b^{\prime -}) < 0.08 MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

    Differential branching fraction and angular analysis of the decay B0→K∗0ÎŒ+Ό−

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    The angular distribution and differential branching fraction of the decay B 0→ K ∗0 ÎŒ + ÎŒ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions

    Observation of excited Lambda_b0 baryons

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    Using pp collision data corresponding to 1.0 fb-1 integrated luminosity collected by the LHCb detector, two narrow states are observed in the Lambda_b0pi+pi- spectrum with masses 5911.97 +- 0.12(stat) +- 0.02(syst) +- 0.66(Lambda_b0 mass) MeV/c^2 and 5919.77 +- 0.08(stat) +- 0.02(syst) +- 0.66(Lambda_b0 mass) MeV/c^2. The significances of the observations are 5.2 and 10.2 standard deviations, respectively. These states are interpreted as the orbitally-excited Lambda_b0 baryons, Lambda_b*0(5912) and Lambda_b*0(5920).Comment: Replaced by version published in Phys. Rev. Lett, modified fit with better mass resolution treatmen

    Observation of associated production of a ZZ boson with a DD meson in the~forward region

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    A search for associated production of a ZZ boson with an open charm meson is presented using a data sample, corresponding to an integrated luminosity of 1.0 fb−‘1.0\,\mathrm{fb}^{-`} of proton--proton collisions at a centre-of-mass energy of 7\,TeV, collected by the LHCb experiment. %% Seven candidate events for associated production of a ZZ boson with a D0D^0 meson and four candidate events for a ZZ boson with a D+D^+ meson are observed with a combined significance of 5.1standard deviations. The production cross-sections in the forward region are measured to be σZ→Ό+ÎŒâˆ’â€‰âŁ,D0=2.50±1.12±0.22pb\sigma_{Z\rightarrow\mu^+\mu^-\!,D^0} = 2.50\pm1.12\pm0.22pb σZ→Ό+ÎŒâˆ’â€‰âŁ,D+=0.44±0.23±0.03pb,\sigma_{Z\rightarrow\mu^+\mu^-\!,D^+} = 0.44\pm0.23\pm0.03pb, where the first uncertainty is statistical and the second systematic.Comment: 18 pages, 2 figure

    Measurement of the relative rate of prompt χc0, χc1 and χc2 production at √s=7TeV

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    Prompt production of charmonium χc0, χc1 and χc2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of √s=7TeV. The χc mesons are identified through their decay to J/ÏˆÎł, with J/ψ→Ό+mu− using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0fb−1 collected by the LHCb detector, is used to measure the relative prompt production rate of χc1 and χc2 in the rapidity range 2.0<y<4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χc0 meson production at a hadron collider is also presented
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