5,602 research outputs found

    Impact differences among the landing phases of a drop vertical jump in soccer players

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    The aim of this study was to examine the differences of landing phase biomechanics between the players who had anterior cruciate ligament (ACL) reconstruction and healthy participants during single leg drop vertical jump. In this study, 11 soccer players who had anterior cruciate ligament reconstruction (aged 23.0±3.6 years, height 177±5.0 cm, weight 83.8±11.7 kg) and 9 healthy soccer players( aged 22.2±2.4 years, height 178±3.0 cm, weight 74.3±6.1 kg) participated voluntarily. During the data collection phase three high speed cameras synchronized to each other and force plate were used. Visual analysis programme and MATLAB were used to calculate kinetic and kinematic variables. Landing techniques of the subjects' were examined by flexion angle of knee, ground reaction force and moment parameters. The statistical analyses of the measured results were performed by t-test and Pearson Correlation analysis. According to the results, it was determined that peak vertical ground reaction force exhibited significant phase differences (p=0.00, and p=0.00, respectively) between the groups. Obtained results can be explained with "quadriceps avoidance" motion pattern which is characterized by decreased quadriceps activity and lower external knee flexion moment in an effort to control anterior translation of the tibia in subjects with ACL reconstruction. A better understanding of the different phases during single-leg landings can shed a light on mechanism of non-contact anterior crucaite ligament injuries therefore future researches should assess how phase differences affect drop vertical jump performance. © 2018 Montenegrin Sports Academy. All rights reserved

    Smoothness of the Green Function for a Special Domain

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    Cataloged from PDF version of article.We consider a compact set K ⊂ ℝ in the form of the union of a sequence of segments. By means of nearly Chebyshev polynomials for K, the modulus of continuity of the Green functions gℂ\K is estimated. Markov's constants of the corresponding set are evaluated. © Instytut Matematyczny PAN, 2012

    Modeling the Influence of Antifreeze Proteins on Three-Dimensional Ice Crystal Melt Shapes using a Geometric Approach

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    The melting of pure axisymmetric ice crystals has been described previously by us within the framework of so-called geometric crystal growth. Nonequilibrium ice crystal shapes evolving in the presence of hyperactive antifreeze proteins (hypAFPs) are experimentally observed to assume ellipsoidal geometries ("lemon" or "rice" shapes). To analyze such shapes we harness the underlying symmetry of hexagonal ice Ih and extend two-dimensional geometric models to three-dimensions to reproduce the experimental dissolution process. The geometrical model developed will be useful as a quantitative test of the mechanisms of interaction between hypAFPs and ice.Comment: 15 pages, 5 figures; Proc. R. Soc. A, Published online before print June 27, 201

    Determination of the accumulator plants in Kucukcekmece Lake (Istanbul)

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    Soils are polluted by actions like using commercial fertilizers, pesticides, soil regulators and hormones to increase the amount and quality of agricultural production, discharge of soil and liquid wastes, performing wastewater sludge applications, using polluted waters in agricultural irrigation, atmospheric precipitations and radioactive sprays. It is an important environmental problem to reform and clean the soils polluted with heavy metals. Phytoremediation is a measure which uses several plants to remove the pollutants from water and soil to reduce, completely extract, control or immobilize them. The plants used for this reason are referred to as the accumulators. Metal accumulation can occur in several different families like small annual grass to perennial bushes and trees. For remediation or cleaning of the soils polluted with heavy metals, the ideal plant species are the ones which can produce high amounts of biomass, and can accumulate and tolerate the pollutants. In this study, the Cd and Zn contents obtained from Kucukcekmece Lake border were monitored on monthly basis and it was aimed at determining the plant species with accumulation ability. The plants chosen for this activity were Labiatae galatica, Compositae cardueae, Cypereace carex, and Phragmites australis. Compositae cardueae was the most efficient species in terms of mean heavy metal intake performance.Key words: Heavy metals, accumulators, phytoremediation, soil pollution, Cd, Zn

    Nutrient contents and in vitro digestibility of different parts of corn plant

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    AbstractThe objective of this study was to assess the nutrient contents and in vitro true digestibility (IVTD) of parts of the corn plant. The corn used in the study was P2088, a variety that is grown widely in Turkey. It had matured and was harvested 140 days after planting. Four replicate plants were separated into nine parts, namely lower stalk, central stalk, upper stalk, corn ear stalk, corn ear shuck, kernels, corn cob, leaf, tassel, plus the entire plant. The samples were dried and ground for analysis. Nutritional values were determined in the laboratory and in vitro digestibility was assessed. Significant differences in nutrient content were observed among parts of the corn plant. The highest crude protein (CP) content was found in the leaf (12.41%), followed by the grain (12.37%). Dry matter (DM) varied from 91.25% to 96.07%. The highest ether extract (EE) was in the grain (2.84%), and the upper stalk contained the least EE (0.29%). The parts also differed in their contents of crude cellulose (CS) and crude ash (CA) (P <0.001). Most organic matter (OM) was found in the corn cup (94.27%). The highest in vitro dry matter digestibility (IVDMD) was in the kernels (79.06%) and the lowest was in the lower stalk (38.13%). In terms of in vitro true organic matter digestibility (OMD) values of the corn plant and its 9 parts, the highest values were found in the kernels and the lowest in the lower stalk.Keywords: crude nutrients, in vitro true digestibility, parts of corn plan

    Influence functions of trimmed likelihood estimators for lifetime experiments

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    We provide a general approach for deriving the influence function for trimmed likelihood estimators using the implicit function theorem. The approach is applied to lifetime models with exponential or lognormal distributions possessing a linear or nonlinear link function. A side result is that the functional form of the trimmed estimator for location and linear regression used by Bednarski and Clarke (1993, 2002) and Bednarski et al. (2010) is not generally always the correct functional form of a trimmed likelihood estimator. However, it is a version for which the influence function has a treatable form. A real data example shows the effect of trimming using a nonlinear link function for either the exponential or lognormal distribution

    Influence functions of trimmed likelihood estimators for lifetime experiments

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    We provide a general approach for deriving the influence function for trimmed likelihood estimators using the implicit function theorem. The approach is applied to lifetime models with exponential or lognormal distributions possessing a linear or nonlinear link function. A side result is that the functional form of the trimmed estimator for location and linear regression used by Bednarski and Clarke (1993, 2002) and Bednarski et al. (2010) is not generally always the correct functional form of a trimmed likelihood estimator. However, it is a version for which the influence function has a treatable form. A real data example shows the effect of trimming using a nonlinear link function for either the exponential or lognormal distribution

    Interactions mechanism of commonly used drugs for the treatment of Covid-19

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    In this study conformation analysis of seven drugs commonly used in the treatment of COVID-19 was performed. The most stable conformers of the drug molecules were used as initial data for docking analysis. Using the Cavityplus program, the probable most active binding sites of both apo and holo forms of COVID-19 main protease enzyme (Mpro) and spike glycoprotein of SARSCoV-2 receptors were determined. The interaction mechanisms of the 7 FDA approved drugs (arbidol, colchicine, dexamethasone, favipiravir, galidesivir, hydroxychloroquine, remdesivir) were examined using the AutoDock Vina program. The six of the seven drugs were found to be more stable in binding to apo form of COVID-19 Mpro and spike glycoprotein. Moreover, a set of molecular mechanics (MM) Poisson-Boltzmann (PB) surface area (SA) calculations on the investigated drugs-protein systems were performed and the estimated binding free energy of remdesivir and the apo form of Mpro system was found to be the best. The interaction results of FDA drugs with the apo form of COVID-19 Mpro and spike glycoprotein can play an important role for the treatment of COVID-19.                     KEY WORDS: COVID-19, Drugs, Molecular modelling, Conformational analysis, Molecular docking   Bull. Chem. Soc. Ethiop. 2020, 34(3), 613-623. DOI: https://dx.doi.org/10.4314/bcse.v34i3.1
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