633 research outputs found

    Higher Twist Effects in Photon-Photon Collisions

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    In this article, we investigate the contribution of the high twist Feynman diagrams to the large pTp_{T} single pseudoscalar and vector mesons inclusive production cross section in two-photon collisions and we present the general formulae for the high and leading twist differential cross sections. The pion wave function where two non-trivial Gegenbauer coefficients a2a_2 and a4a_4 have been extracted from the CLEO data, Braun-Filyanov pion wave function, the asymptotic and the Chernyak-Zhitnitsky wave functions are used in the calculations. For ρ\rho-meson we used Ball-Braun wave function. The results of all the calculations reveal that the high twist cross sections, the ratio R, the dependence transverse momentum pTp_{T} and the rapidity yy of meson in ΦCLEO(x,Q2)\Phi_{CLEO}(x,Q^2) wave function case is very close to the Φasy(x)\Phi_{asy}(x) asymptotic wave function case. It is shown that the high twist contribution to the cross section depends on the choice of the meson wave functions.Comment: REVTEX4, 23 pages, 7 figure

    Higher Twist Effects in Proton-Proton Collisions

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    In this article, we investigate the contribution of the high twist Feynman diagrams to the large-pTp_T pion production cross section in proton-proton collisions and we present the general formulae for the high and leading twist differential cross sections. The pion wave function where two non-trivial Gegenbauer coefficients a2a_2 and a4a_4 have been extracted from the CLEO data, two other pion model wave functions, P2P_2, P3P_3, the asymptotic and the Chernyak-Zhitnitsky wave functions are used in the calculations. The results of all the calculations reveal that the high twist cross sections, the ratios RR, rr, the dependence transverse momentum pTp_T and the rapidity yy of pion in the ΦCLEO(x,Q2)\Phi_{CLEO}(x,Q^2) wave function case is very close to the Φasy(x)\Phi_{asy}(x) asymptotic wave function case. It is shown that the high twist contribution to the cross section depends on the choice of the meson wave functions.Comment: 28 pages 18 figures RevTex

    Investigation of the nuetralino pair production at LHC

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    In this article, we investigate the Drell-Yan process of the light neutralino pair χ~i0χ~j0\widetilde{\chi}_{i}^{0}\widetilde{\chi}_{j}^{0} (i,j=1,2i,j=1,2) productions at proton-proton collisions and we present the general formulate for the differential cross sections. We conduct an extensive examination of the dependence of the total cross section of the subprocesses qqˉχ~i0χ~j0q \bar q \to \widetilde \chi_{i}^{0}\widetilde\chi_{j}^{0} on the beam energy, on the mass of the squarks and also on the M2M_2 gaugino for the three extremely different scenarios. For all three cases, the outcomes are as follows. The dependence of the total cross section of the subprocesses qqˉχ~i0χ~j0q \bar q \to \widetilde \chi_{i}^{0} \widetilde \chi_{j}^{0} on the beam energy is dominated by one of the subprocesses, qqˉχ~10χ~20q \bar q \to \widetilde \chi_{1}^{0} \widetilde \chi_{2}^{0}. On the other hand, the dependence of the total cross section of the subprocesses qqˉχ~i0χ~j0q \bar q \to \widetilde \chi_{i}^{0} \widetilde \chi_{j}^{0} on the mass of the squarks is dominated by one of the subprocesses, qqˉχ~10χ~20q \bar q \to \widetilde \chi_{1}^{0} \widetilde \chi_{2}^{0}. We derive there from that our findings may lead to new insights relating to experimental investigations and these dependencies may be used as bases of an experimental research for the neutralino pair at LHC.Comment: 38pp, 22 figures, ReVTeX4, (Baku State University, Azerbaijan, and Erciyes University, Kayseri, Turkey

    Drought and oxidative stress

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    Drought, a natural stress factor has the highest percentage with 26%, when the usable areas on the earth are classified in view of stress factors. Biotic and abiotic stress factors may cause yield loss in plants and affect human and animal nutrition. Amount of lacking yield due to biotic and abiotic stress factors ranged between 65 and 87%. The best option for crop production, yield improvement and yield stability under soil moisture deficient conditions is to develop drought tolerant crop varieties (Siddique et al., 2000). A physiological approach would be the most attractive way to develop new varieties rapidly. Only few studies highlighted the importance of antioxidant enzymes during drought stress. The antioxidant defenses appear to provide crucial protection against oxidative damage in cellular membranes and organelles in plants grown under unfavorable conditions. Thus, plants are equipped with complex and a highly efficient antioxidative defense system which can respond and adapt to drought stress. This system is composed of protective nonenzymatic and enzymatic protection mechanisms. They interrupt the uncontrolled oxidation and serve to maintain the antioxidants in their reduced functional state, that efficiently scavenge ROS (reactive oxygen species) and prevent damaging effects of free radicals. Balance at aerobic metabolism is defined as free radical generation and rapid removal by antioxidant systems. The structure of cells and functional changes of systems, may be damaged by the formation of irreversible oxidative stress. Redox signalling and antioxidative defense systems are very important for protection towards uncontrolled and cascade damage of biotic and abiotic stress factors. In this review, drought, drought types and antioxidative defense system components will be discussed.Key words: Antioxidative defense system, ascorbate peroxidase, catalase, drought types, glutathione reductase, oxidative stress, superoxide dismutase

    Ontology-based data access to Slegge

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    We report on our experience in ontology-based data access to the Slegge database at Statoil and share the resources employed in this use case: end-user information needs (in natural language), their translations into SPARQL, the Subsurface Exploration Ontology, the schema of the Slegge database with integrity constraints, and the mappings connecting the ontology and the schema

    Bound state solutions of the Dirac-Rosen-Morse potential with spin and pseudospin symmetry

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    The energy spectra and the corresponding two- component spinor wavefunctions of the Dirac equation for the Rosen-Morse potential with spin and pseudospin symmetry are obtained. The ss-wave (κ=0\kappa = 0 state) solutions for this problem are obtained by using the basic concept of the supersymmetric quantum mechanics approach and function analysis (standard approach) in the calculations. Under the spin symmetry and pseudospin symmetry, the energy equation and the corresponding two-component spinor wavefunctions for this potential and other special types of this potential are obtained. Extension of this result to κ0\kappa \neq 0 state is suggested.Comment: 18 page

    CHARACTERIZATION OF CYLINDROCARPON-LIKE ANAMORPHS CAUSING ROOT AND BASAL ROT OF APRICOT AND IN VITRO ACTIVITIES OF SOME FUNGICIDES

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    Four apricot nurseries were surveyed in Hatay province in Turkey to evaluate the phytosanitary status of the nursery plant material. Endophytic and potential pathogenic fungi were identified in plants and 12 Cylindrocarpon-like anamorph isolates were detected in the root system and basal stems of analyzed rootstocks. Based on partial sequencing ITS, three different  Cylindrocarpon-like anamorph species were identified as Dactylonectria torresensis (6 isolates), Dactylonectria novozelandica (3 isolates) and Neonectria candida (3 isolates). Pathogenicity tests were conducted under greenhouse conditions which showed that all three Cylindrocarpon-like anamorph species, were identified as pathogens. ADt12 (D. torresensis) isolate, obtained from the survey area, have been tested in vitro for its sensitivity to several fungicides (thiophanate-methyl (70%), fluazinam (500g/L), fludioxonil (230g/L), and boscalid (26.7%)+pyraclostrobin (6.7%)). It was determined that ADt12 isolate was highly sensitive to fludioxonil and fluazinam, and sensitive to thiophanate-methyl and boscalid+pyraclostrobin as a result of probit analysis of EC50 values

    Racial/ethnic differences in health insurance adequacy and consistency among children: Evidence from the 2011/12 National Survey of Children’s Health

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    Background: Surveillance of disparities in healthcare insurance, services and quality of care among children are critical for properly serving the medical/healthcare needs of underserved populations. The purpose of this study was to assess racial/ethnic differences in children’s (0 to 17 years old) health insurance adequacy and consistency (child has insurance coverage for the last 12 months). Design and methods: We used data from the 2011/2012 National Survey of Children’s Health (n=79,474). Descriptive statistics and logistic regression analyses were conducted to examine the distribution and influence of several sociodemographic/family related factors on insurance adequacy and consistency across different racial/ethnic groups. Results: Stratified analyses by race/ethnicity revealed that white and black children living in households at or below 299% of the Federal Poverty Level (FPL) were approximately 29 to 42% less likely to have adequate insurance compared to children living in families of higher income levels. Regardless of race/ethnicity, we found that children with public health insurance were more likely to have adequate insurance than their privately insured counterparts, while adolescents were at greater risk of inadequate coverage. Hispanic and black children were more likely to lack consistent insurance coverage. Conclusions: This study provides evidence that racial/ethnic differences in adequate and consistent health insurance exists with both white and minority children being affected adversely by poverty. Establishing outreach programs for low income families, and cross-cultural education for healthcare providers may help increase health insurance adequacy and consistency within certain underserved populations

    Clinicopathological Profile and Surgical Treatment of Abdominal Tuberculosis: A Single Centre Experience in Northwestern Tanzania.

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    Abdominal tuberculosis continues to be a major public health problem worldwide and poses diagnostic and therapeutic challenges to general surgeons practicing in resource-limited countries. This study was conducted to describe the clinicopathological profile and outcome of surgical treatment of abdominal tuberculosis in our setting and compare with what is described in literature. A prospective descriptive study of patients who presented with abdominal tuberculosis was conducted at Bugando Medical Centre (BMC) in northwestern Tanzania from January 2006 to February 2012. Ethical approval to conduct the study was obtained from relevant authorities. Statistical data analysis was performed using SPSS version 17.0. Out of 256 patients enrolled in the study, males outnumbered females. The median age was 28 years (range = 16-68 years). The majority of patients (77.3%) had primary abdominal tuberculosis. A total of 127 (49.6%) patients presented with intestinal obstruction, 106 (41.4%) with peritonitis, 17 (6.6%) with abdominal masses and 6 (2.3%) patients with multiple fistulae in ano. Forty-eight (18.8%) patients were HIV positive. A total of 212 (82.8%) patients underwent surgical treatment for abdominal tuberculosis. Bands /adhesions (58.5%) were the most common operative findings. Ileo-caecal region was the most common bowel involved in 122 (57.5%) patients. Release of adhesions and bands was the most frequent surgical procedure performed in 58.5% of cases. Complication and mortality rates were 29.7% and 18.8% respectively. The overall median length of hospital stay was 32 days and was significantly longer in patients with complications (p < 0.001). Advanced age (age ≥ 65 years), co-morbid illness, late presentation, HIV positivity and CD4+ count < 200 cells/μl were statistically significantly associated with mortality (p < 0.0001). The follow up of patients were generally poor as only 37.5% of patients were available for follow up at twelve months after discharge. Abdominal tuberculosis constitutes a major public health problem in our environment and presents a diagnostic challenge requiring a high index of clinical suspicion. Early diagnosis, early anti-tuberculous therapy and surgical treatment of the associated complications are essential for survival
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