1,480 research outputs found

    Jackiw-Teitelboim Gravity Generates Horndeski via Disformal Transformations

    Full text link
    We show that the most general two-dimensional dilaton gravity theory with second-order field equations, which includes Horndeski and Kinetic Gravity Braiding families, may be obtained from the Jackiw-Teitelboim (JT) gravity through a general disformal transformation, up to boundary terms. We also show that this most general family of theories is closed under generic disformal transformations.Comment: 13 pages, 1 figure

    Discrete alpha-skew-Laplace Distribution

    Get PDF
    Classical discrete distributions rarely support modelling data on the set of whole integers. In this paper, we shall introduce a flexible discrete distribution on this set, which can, in addition, cover bimodal as well as unimodal data sets. The proposed distribution can also be fitted to positive and negative skewed data. The distribution is indeed a discrete counterpart of the continuous alpha-skew-Laplace distribution recently introduced in the literature. The proposed distribution can also be viewed as a weighted version of the discrete Laplace distribution. Several distributional properties of this class such as cumulative distribution function, moment generating function, moments, modality, infinite divisibility and its truncation are studied. A simulation study is also performed. Finally, a real data set is used to show applicability of the new model comparing to several rival models, such as the discrete normal and Skellam distributions

    Developing an Improved Shift-and-Invert Arnoldi Method

    Get PDF
    An algorithm has been developed for finding a number of eigenvalues close to a given shift and in interval [ Lb,Ub ] of a large unsymmetric matrix pair. The algorithm is based on the shift-andinvert Arnoldi with a block matrix method. The block matrix method is simple and it uses for obtaining the inverse matrix. This algorithm also accelerates the shift-and-invert Arnoldi Algorithm by selecting a suitable shift. We call this algorithm Block Shift-and-Invert or BSI. Numerical examples are presented and a comparison has been shown with the results obtained by Sptarn Algorithm in Matlab. The results show that the method works well

    Comparison of quality of life between myopic patients with spectacles and contact lenses, and patients who have undergone refractive surgery

    Get PDF
    Purpose: The present study aims at investigating and comparing the vision-related quality of life of myopic persons who wear spectacles or contact lenses with those who have undergone refractive surgery. It also compares the vision-related quality of life of these two groups with that of emmetropes. Method: In this study, the questionnaire of evaluation instrument of refractive error in quality of life (NEI/RQL-42) was used to compare the quality of life between 154 myopic patients with spectacles and contact lenses, and 32 patients who have undergone refractive surgery. The two groups were also compared with 54 emmetropes. The questionnaire included 13 different subgroups (score 0-100) related to vision. Data was analyzed using SPSS software. Results: The overall score of quality of life in emmetropes (95.11 ± 4.23) was more than that in persons who had undergone refractive surgery (86.98 ± 4.73), and it was the least in the group wearing spectacles or contact lenses (78.30 ± 9.21), (P < 0/001). Furthermore, except for a glare variable, the studied groups indicated a statistically significant difference in all the thirteen subgroups of vision-related quality of life. Conclusion: Quality of life for people with myopia who had the refractive surgery was better than people with myopia who wore spectacles or contact lenses. Although quality of life in people with myopia who had the refractive surgery was less than emmetropia, it seems that refractive surgery improves quality of life of myopic patients. © 2015

    The Status of Natural Radioactivity and Heavy Metals Pollution on Marine Sediments Red Sea Coast, At Safaga, Egypt

    Get PDF
    Natural 226Ra, 232Th and 40K radio nuclides concentration in beach Sediments along Safaga coast of Red sea, Egypt has been carried out using a NaI (Tl) gamma ray spectrometric technique. The total average concentrations of radionuclides ± uncertainty of 226Ra, 232Th and 40K were 22.2 ± 1.7, 19.2 ± 2.5, and 477.6 ± 27.6 Bqkg-1, respectively. The total average absorbed dose rate is found to be 41.4 nGyh-1, whereas the annual effective dose rate has an average value of 54 μSvy-1. The total organic matter (TOC), carbonates (CaCo3) and Heavy metals distribution have been measured at some locations, the concentration for the investigated heavy metals overtake the allowable limits recommended by the Canadian Environmental Quality Guidelines, this assigned to the ratio of metals pollution is caused by anthropogenic activities (phosphate shipment as in Abu Tartour harbor and navigation as in Touristic harbor) and or by natural impacts such in mangrove interment. Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclide

    Type 2 Diabetes Mellitus-Induced Hyperglycemia in Patients with NAFLD and Normal LFTs: Relationship to Lipid Profile, Oxidative Stress and Pro-Inflammatory Cytokines

    Get PDF
    Type 2 diabetes mellitus is associated with dyslipdemia, insulin resistance and non alcoholic fatty liver disease. The purpose of the current study was to assess whether type 2 diabetes mellitus-induced hyperglycemia has an effect on the lipid profile and release of oxidative stress markers and inflammatory mediators in patients with non alcoholic fatty liver disease and normal liver function tests which may in turn lead to enhancing the pathogenicity of this liver disease. For this purpose, one hundred and five outpatients, matched in age and weight, were classified into two groups: the first group consisted of patients with non alcoholic fatty liver disease and the second group consisted of patients with non alcoholic fatty liver disease in conjunction with hyperglycemia due to the presence of type 2 diabetes mellitus. In all patients, lipid profile, oxidative stress, and inflammatory mediators were assessed by measuring serum concentrations of triglycerides, low density lipoprotein, hydrogen preroxide, malondialdehyde, tumor necrosis factor-alpha and interleukin-6, respectively. In the studied population, it was found that the presence of type 2 diabetes mellitus-induced hyperglycemia significantly impaired lipid profile, and significantly enhanced the formation of hydrogen preroxide and malondialdehyde as well as significantly increased the release of tumor necrosis factor-alpha and interleukin-6 in the second group of patients. In addition, plasma glucose level showed significant positive correlation with hydrogen peroxide, malondialdehyde, tumor necrosis factor-alpha and interleukin-6. From the previous results, it was concluded that the presence of type 2 diabetes mellitus-induced hyperglycemia results in significant increase in lipid profile, oxidative stress markers and inflammatory mediators in patients with non alcoholic fatty liver disease and normal liver function tests. For this reason, further research studies may be essential to evaluate the benefit of adding suitable antioxidant and anti-inflammatory drugs to the treatment regimen for this group of patients. In addition, regular monitoring of blood glucose levels and liver function tests should be advised to this category of patients to reduce liver fat deposition and avoid the development of non alcoholic steatohepatitis, cirrhosis or liver cancer and their related complications

    Distribution of multiband THz wireless signals over fiber

    Get PDF
    Terahertz wireless communication is receiving great interest from researchers and industries, thanks to the new spectral windows between 0.1 and 1 THz offering opportunities for ultra-high-data-rate wireless transmission. Wavelength division multiplexing for wireless-over-fiber is foreseen as an enabling technique to support connection between base stations and a central station. This paper reviews architectures for photonic distribution and generation of multiband signals for sub- THz wireless communications, giving rates up to 100 Gb/s (20 Gb/s per band) using the full spectrum between 220 GHz and 280 GHz for downlink wireless transmission, and 10 Gb/s for uplink using on-off keying
    corecore