1,300 research outputs found

    Prediction for Nonabelian Fine Structure Constants from Multicriticality

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    In developing a model for predicting the nonabelian gauge coupling constants we argue for the phenomenological validity of a ``principle of multiple point criticality''. This is supplemented with the assumption of an ``(grand) anti-unified'' gauge group SMGNgen.∌U(1)Ngen.×SU(2)Ngen.×SU(3)Ngen.SMG^{N_{gen.}}\sim U(1)^{N_{gen.}}\times SU(2)^{N_{gen.}}\times SU(3)^{N_{gen.}} that, at the Planck scale, breaks down to the diagonal subgroup. Here NgenN_{gen} is the number of generations which is assumed to be 3. According to this ``multiple point criticality principle'', the Planck scale experimental couplings correspond to multiple point couplings of the bulk phase transition of a lattice gauge theory (with gauge group SMGNgen.SMG^{N_{gen.}}). Predictions from this principle agree with running nonabelian couplings (after an extrapolation to the Planck scale using the assumption of a ``desert'') to an accuracy of 7\%. As an explanation for the existence of the multiple point, a speculative model using a glassy lattice gauge theory is presented.Comment: 42, NBI-HE-93-2

    Quantum information cannot be split into complementary parts

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    We prove a new impossibility for quantum information (the no-splitting theorem): an unknown quantum bit (qubit) cannot be split into two complementary qubits. This impossibility, together with the no-cloning theorem, demonstrates that an unknown qubit state is a single entity, which cannot be cloned or split. This sheds new light on quantum computation and quantum information.Comment: 9 pages, 1 figur

    The occurrence and characterization of Campylobacter jejuni and C. coli in organic pigs and their outdoor environment

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    The occurrence and species distribution of thermophilic Campylobacter was investigated in organic outdoor pigs. An increased exposure of outdoor pigs to C. jejuni from the environment may cause a shift from a normal dominance of C. coli to more C. jejuni, which may imply a concern of reduced food safety. Bacteriological methods for determination of Campylobacter excretion level were combined with colony-blot hybridization and real-time PCR for specific detection of C. jejuni in pigs. Campylobacter was isolated from pigs (n = 47), paddock environment (n = 126) and wildlife (n = 44), identified to species by real-time PCR and sub-typed by serotyping (Penner) and pulse-field gel electrophorsis (PFGE) genotyping. All pigs excreted Campylobacter (103–107 CFU g1 faeces) from the age of 8–13-weeks old. C. jejuni was found in 29% of pigs in three consecutive trials and always in minority to C. coli (0.3–46%). C. jejuni and C. coli were isolated from 10% and 29% of the environmental samples, respectively, while crow-birds and rats harboured C. jejuni. Individual pigs hosted several strains (up to nine serotypes). The paddock environment was contaminated with C. coli serotypes similar to pig isolates, while most of the C. jejuni serotypes differed. C. jejuni isolates of different origin comprised few similar serotypes, just one identical genotype was common between pigs, environment and birds. In conclusion, the occurrence of C. jejuni varied considerably between the three groups of outdoor pigs. Furthermore, transfer of C. jejuni to the outdoor pigs from the nearby environment was not predominant according to the subtype dissimilarities of the obtained isolates

    Comparison of serology and culture for detecting Salmonella infection of 5 to 7 month old swine

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    There was a significant direct correlation between the presence of Salmonella in ileocecal lymph nodes and the titer of antibody to Salmonella in meat juice. It was also demonstrated that there is no significant correlation between titer of antibody in serum collected from pigs immediately prior to slaughter and the presence of Salmonella in the feces on the floor of pens. These conclusions suggest that the level of antibody to Salmonella in meat juice can be used to determine whether or not groups of pigs at slaughter contain Salmonella in their ileocecal lymph nodes

    N-qubit entanglement via the Jy2J_y^2-type collective interaction

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    We investigate quantum correlations of the NN-qubit states via a collective pseudo-spin interaction (∝Jy2\propto J_y^2) on arbitrary pure separable states for a given interval of time. Based on this dynamical generation of the NN-qubit maximal entangled states, a quantum secret sharing protocol with NN continuous classical secrets is developed.Comment: 12 pages, 3 figure

    A novel procedure for fast surface structural analysis based on LEED intensity data

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    By evaluating LEED intensities from different diffraction beams taken only at discrete energy intervals (which may be as large as 15–20 eV) the same degree of reliability in surface structure determination can be reached as with the conventional techniques based on analysis of continuous I/V-spectra. The minimum of the corresponding R-factor can be found by a least-squares fit method, as will be exemplified with a system in which 8 structural parameters were subject to simultaneous refinement

    The structure ofAl(111)-K−(√3 × √3)R30° determined by LEED: stable and metastable adsorption sites

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    It is found that the adsorption of potassium on Al(111) at 90 K and at 300 K both result in a (√3 × √3)R0° structure. Through a detailed LEED analysis it is revealed that at 300 K the adatoms occupy substitutional sites and at 90 K the adatoms occupy on-top sites; both geometries have hitherto been considered as very unusual. The relationship between bond length and coordination is discussed with respect to the present results, and with respect to other quantitative studies of alkali-metal/metal adsorption systems

    Incompatibility Systems in Switchgrass

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    Switchgrass (Panicum virgatum L.), a cross-pollinated perennial, produces very little or no seed when self-pollinated, indicating the presence of self-incompatibility mechanisms. Knowledge of self-incompatibility mechanisms is required to use germplasm effectively in a breeding program. The objective of this study was to characterize features of the incompatibility systems in switchgrass. Seed set and seed characteristics of reciprocal matings of tetraploid, octaploid, and tetraploid x octaploid plants were used as measures of incompatibility. Both bagged mutual pollination and manual emasculation and pollination methods were used to make crosses. The percentages of self-compatibility in the tetraploid and octaploid parent plants were 0.35 and 1.39%, respectively. Prefertilization incompatibility in switchgrass is apparently under gametophytic control, since there were significant differences in percentage of compatible pollen as measured by percentage of total seed set between reciprocal matings within ploidy levels. Results indicated that the prefertilization incompatibility system in switchgrass is similar to the S-Z incompatibility system found in other members of the Poaceae. A postfertilization incompatibility system also exists that inhibits intermatings among octaploid and tetraploid plants. In these interploidy crosses, two very distinctive types of abnormal seed were found. When the female parent was the tetraploid plant, the resulting seed was small and shriveled, while when the female parent was the octaploid, small seed with floury endosperm was obtained. These results are similar to those obtained for endosperm incompatibility due to the endosperm balance number system found in other species

    miR-345 in metastatic colorectal cancer: a non-invasive biomarker for clinical outcome in non-KRAS mutant patients treated with 3rd line cetuximab and irinotecan.

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    INTRODUCTION: MicroRNAs (miRNAs) have important regulatory functions in cellular processes and have shown promising potential as prognostic markers for disease outcome in patients with cancer. The aim of the present study was to find miRNA expression profiles in whole blood that were prognostic for overall survival (OS) in patients with metastatic colorectal cancer (mCRC) treated with cetuximab and irinotecan. METHODS: From 138 patients with mCRC in 3rd line therapy with cetuximab and irinotecan in a prospective phase II study, 738 pretreatment miRNAs were isolated and profiled from whole blood using the TaqMan MicroRNA Array v2.0. Mutation status of KRAS, BRAF, and PI3KCA was known. RESULTS: After Bonferroni adjustment, 6 miRNAs: (miR-345, miR-143, miR-34a*, miR-628-5p, miR-886-3p and miR-324-3p), were found associated with short OS. miR-345 was the strongest prognostic miRNA, significant in the full cohort and in the non-KRAS mutant population. miR-345, as a continuous variable in the full cohort, resulted in a hazard ratio (HR) of 2.38 per IQR (CI 95%: 1.8-3.1, P-value = 2.86e-07, Bonferroni adjusted, univariable analysis) and a HR = 1.75 per IQR (CI 95%: 1.24-2.48, P-Wald = 1.45e-03) in the multivariable analysis adjusted for gender, age, KRAS, PI3KCA and performance status. miR-345 was prognostic in progression-free survival (PFS) with a HR = 1.63 per IQR (CI 95%: 1.25-2.114, P-Wald = 2.92e-4) in the multivariable analysis. In addition, high miR-345 expression was associated with lack of response to treatment with cetuximab and irinotecan. CONCLUSION: We identified miR-345 in whole blood as a potential biomarker for clinical outcome. MiR-345 was a single prognostic biomarker for both OS and PFS in all patients and also in the non-KRAS mutant population
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