176 research outputs found

    Cup Products in Hopf-Cyclic Cohomology

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    We construct cup products of two different kinds for Hopf-cyclic cohomology. When the Hopf algebra reduces to the ground field our first cup product reduces to Connes' cup product in ordinary cyclic cohomology. The second cup product generalizes Connes-Moscovici's characteristic map for actions of Hopf algebras on algebras.Comment: 7 pages. To appear in C. R. Acad. Sci. Pari

    Stable anti-Yetter-Drinfeld modules

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    We define and study a class of entwined modules (stable anti-Yetter-Drinfeld modules) that serve as coefficients for the Hopf-cyclic homology and cohomology. In particular, we explain their relationship with Yetter-Drinfeld modules and Drinfeld doubles. Among sources of examples of stable anti-Yetter-Drinfeld modules, we find Hopf-Galois extensions with a flipped version of the Miyashita-Ulbrich action

    Blind Source Separation in Nonlinear Mixture for Colored Sources Using Signal Derivatives

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    International audienceWhile Blind Source Separation (BSS) for linear mixtures has been well studied, the problem for nonlinear mixtures is still thought not to have a general solution. Each of the techniques proposed for solving BSS in nonlinear mixtures works mainly on specific models and cannot be generalized for many other realistic applications. Our approach in this paper is quite different and targets the general form of the problem. In this advance, we transform the nonlinear problem to a time-variant linear mixtures of the source derivatives. The proposed algorithm is based on separating the derivatives of the sources by a modified novel technique that has been developed and specialized for the problem, which is followed by an integral operator for reconstructing the sources. Our simulations show that this method separates the nonlinearly mixed sources with outstanding performance; however , there are still a few more steps to be taken to get to a comprehensive solution which are mentioned in the discussion

    Spin-Gravity Coupling in a Rotating Universe

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    The coupling of intrinsic spin with the nonlinear gravitomagnetic fields of Goedel-type spacetimes is studied. We work with Goedel-type universes in order to show that the main features of spin-gravity coupling are independent of causality problems of the Goedel universe. The connection between the spin-gravitomagnetic field coupling and Mathisson's spin-curvature force is demonstrated in the Goedel-type universe. That is, the gravitomagnetic Stern--Gerlach force due to the coupling of spin with the gravitomagnetic field reduces in the appropriate correspondence limit to the classical Mathisson spin-curvature force.Comment: 37 page

    Investigating the Effect of Geocell Changes on Slope Stability in Unsaturated Soil

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    The purpose of this research is to investigate the performance and efficiency of reinforced slope in the stability of geocell layers in unsaturated soil conditions. Slope reinforced with geocell acts like a beam in the soil due to the geocell having a height (three-dimensional). Due to its flexural properties, it has moment of inertia as well as bending strength, which reduces the displacement and increases the safety factor of the slope. Taking into consideration unsaturated conditions of soil contributes a lot to making results close to reality. One of the well-known models among elastoplastic models for modeling unsaturated soils is Barcelona Basic Model, which has been added to the FLAC2D software by codification. Changes in thickness, length and number of geocell layers are remarkably effective on slope stability. The results show that the geocell\u27s reinforcing efficiency depends on the number of layers and depth of its placement. As the depth of the geocell\u27s first layer increases, the lateral and vertical side elevation of the upper part of the slope increases with respect to the elevation. Load capacity increases with increasing geocell length. By increasing the length of the geocell layer, the joint strength, the mobilized tensile strength, and the bending moment are increased. At u/H = 0.2, an increase in the bending momentum of about 20% occurs with increasing geocell thickness. In u/H = 1, the increase in bending momentum is 10.4%. In addition, by increasing the thickness of the geocell, the Value of moment of the inertia increases and, as a result, the amount of geocell reinforcement bending moment increases

    Cup products in Hopf-cyclic cohomology

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    Corporate Social Responsibility, Consumption Values and Consumers Choice Behaviour

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    The aim of current paper is to identify key consumer variables that determine Croatian consumers’ behaviour in relation to CSR of companies in Croatia and check if these factors and behaviour correspond to CSR activities performed by companies. Corporate social responsibility (CSR) can take various forms. Its emphasis can be on consumers, environment and/ or employees. The major goal of CSR activities, whoever they are aimed at, is to create an image of a company as responsive to the society and based on that, build the competitive advantage.  Research of consumers with respect to CSR has been mainly concentrated on cognitive and affective as well as behavioural factors that influence their buying decisions.  Such research has not been performed in Croatia, where the CSR concept is rather a new phenomenon. In general, Croatian consumers are willing to support companies’ CSR activities by paying a higher price for products with CSR attributes if the area of comparable quality and availability. The results show the influence of social values on consumer attitudes towards CSR, but also the low level of knowledge on the subject as well as trust to companies self-promoting their CSR activities. Keywords: corporate social responsibility, consumers, Croati

    Changes in Corneal Asphericity after MyoRing Implantation in Moderate and Severe Keratoconus

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    Purpose: To evaluate the effect of MyoRing implantation on corneal asphericity in moderate and severe keratoconus (KCN). Methods: This cross-sectional observational study comprised 32 eyes of 28 patients with KCN, who had femtosecond-assisted MyoRing corneal implantation. The primary outcome measures were preoperative and six-month postoperative corneal asphericity in 6-, 7-, 8-, 9-, and 10-mm optical zones in the superior, inferior, nasal, temporal, and central areas. The secondary outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, thinnest location value, and keratometry readings. Results: A significant improvement in the UDVA and CDVA was observed six months after the surgery (P < 0.001) with a significant reduction in the spherical (4.67 diopters (D)) and cylindrical (2.19 D) refractive errors. A significant reduction in the corneal asphericity in all the optical zones and in the superior, inferior, nasal, temporal, and central areas was noted (P < 0.001). The mean thickness at the thinnest location of the cornea decreased from 437.15 ± 30.69 to 422.81 ± 36.91 μm. A significant corneal flattening was seen. The K1, K2, and Km changes were 5.32 D, 7 D, and 6.17 D, respectively (P < 0.001). Conclusion: MyoRing implantation is effective for improving corneal asphericity in patients with KCN. It allows successful corneal remodeling and provides a significant improvement in UDVA, CDVA, and refractive errors

    Effects of ginger extract on smooth muscle activity of sheep reticulum and rumen

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    Reticulorumen hypomotility leads to the impaired physiologic functions of the digestive tract. Prokinetic action of ginger has been demonstrated in the laboratory animals and human. The aim of this study was to evaluate the effect of hydroalcoholic extract of ginger on contraction and motility of reticulum and rumen of ruminants. Collected samples of reticulum and rumen from eight sheep were investigated in vitro. The extract at the concentration of 0.1 and 1.0 mg L-1 had no effect on any preparations. Contraction of reticulum and rumen preparations was occurred at 10.0 and 100 mg L-1 concentrations (p < 0.05). Concentration of 1000 mg L-1 caused a relaxation in preparations contracted with 10.0 and 100 mg L-1. Likewise, the concentration of 1000 mg L-1 significantly (p < 0.05) inhibited ACh-induced contraction in both tissues. Six sheep were involved in electromyographic study. Administration of 40 mg kg-1 of the extract increased the overall frequency of contractions of the reticulum and rumen at the subsequent three days with the prominent increase at the second day (p < 0.05). Results of in vitro study indicated that hydroalcoholic extract of ginger contained spasmogenic and spasmolytic constituents. The results in vivo study represented evidences that the extract may have stimulant effect on reticulorumen motility in 40 mg kg-1 concentration

    The effect of food service system modifications on staff body mass index in an industrial organization

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    Due to the adverse effects of obesity and overweight on health status of people, organizations that provide daily food aim for a healthy Body Mass Index among their staff. The purpose of this applied randomized controlled trial (RCT) was to study the effect of modifications in the food service section and nutritional intervention on the BMI of staff in an industrial center. In this applied randomized controlled trial which lasted for 40 days, 116 overweight people (BMI ≥ 26) were randomly selected and divided into control and test groups. Individual daily food plan was prepared by a dietitian and nutritional education sessions were held for test group. At the management level, food menu was modified reduce the calorie intake by at least 1000 Kcal per day for the test group and also cost less for the center. The kitchen staffs were trained to promote healthy cooking and improving the food taste. The satisfaction level of food service was also evaluated before and after the intervention, using a questionnaire. To analyze the findings, SPSS 16 software, independent t-test and paired t-test, and Macnemar test were used. The results showed that BMI in test group decreased from 27.5 ± 2.36 to 26.8 ± 2.15 (p&lt;0.05), while in control group increased by 0.5 Kg/m2. Similar result was observed in weight change. The level of satisfaction of food service following changes in the menu increased significantly in both groups. Also, cost of food and use of fat were reduced by 15% and 8%, respectively.  Dietary interventions and improving the nutritional knowledge along with modification in food service system could result in better weight management in organization staff using canteen food.  
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