199 research outputs found

    The effect of dietary dextrin levels on growth performance, body composition and hepatosomatic index in juvenile Siberian sturgeon, Acipenser baerii

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    The present study was carried out to determine the ability of Acipenser baerii in utilizing carbohydrate (dextrin) as a non protein energy source substituted with animal oil. A total of 65 juveniles A. baerii with an initial mean weight of 689 ± 62 g were distributed in 15 fiber glass tanks. Five diets were formulated including 0, 5, 10, 15 and 20% of dextrin and fed for 8 weeks. Fish were weighed monthly and growth was evaluated in each treatment. At the end of experiment, body composition and hepatosomatic index were analyzed. There was no significant differences in body weight increase (BWI) and final weight (FW) among different groups (p>0.05). Increase of dextrin levels in diets led to an increase in feed conversation ratio (FCR) in fish fed diets containing 15 and 20% dextrin as compared to that in the control group and in fish fed the diet containing 10% dextrin although the differences were not significant (p>0.05). The specific growth rate (SGR) in all treatments were the same (p>0.05). The highest body protein and lipid were observed in fish fed diets containing 10 and 20% dextrin, respectively (p0.05). In conclusion, juvenile A. baerii can be fed diets with high levels of dietary dextrin as a non protein energy source with no deleterious effects and a partial replacement of cheap carbohydrate with lipid is suggested to obtain the necessary energy in commercial diets

    Fast spectral solutions of the double-gyre problem in a turbulent flow regime

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    Several semi-analytical models are considered for a double-gyre problem in a turbulent flow regime for which a reference fully numerical eddy-resolving solution is obtained. The semi-analytical models correspond to solving the depth-averaged Navier–Stokes equations using the spectral Galerkin approach. The robustness of the linear and Smagorinsky eddy-viscosity models for turbulent diffusion approximation is investigated. To capture essential properties of the double-gyre configuration, such as the integral kinetic energy, the integral angular momentum, and the jet mean-flow distribution, an improved semi-analytical model is suggested that is inspired by the idea of scale decomposition between the jet and the surrounding flow

    Primary culture of ovarian follicular cells of Sterlet, Acipenser ruthenus to develop an in vitro system

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    The aim of the present study was to develop an in vitro system for functional investigation of ovarian follicular cells in Sterlet, Acipenser ruthenus. Oocytes for the primary culture were obtained from the ovaries of a 6 years old Sterlet 729 g in weight and 47 cm in total length. The oocytes were in advanced vitellogenesis stage (PI >10). A part of the ovary (containing about 300 follicles) was removed, ovarian follicles isolated by manually removing those from the interstitial tissue and washed with sterile phosphate buffered saline (PBS) containing antibiotics and Amphotericin B. Follicular cells were separated by treating oocytes with 0.25% trypsin-EDTA in Ca2+ and Mg2+ free PBS and cultured in medium L-15 supplemented with 20% FBS, streptomycin sulphate (Gibco, 100 mg.ml-1), penicillin G potassium (Gibco, 100 IU.ml-1) and Amphotericin B (Gibco, 2.5 mg.ml-1) at 22 °C. The concentrations of Testosterone (T), Estradiol-17ÎČ (E2), Progesterone (P4) and 17α-hydroxyprogestron (17αOHP) in the medium were measured at days 3, 5 & 7 by the Enzyme-Linked Immunosorbent Assay. According to the results, the ovarian follicular cells of Sterlet proliferated in L-15 medium were steroidogenically active as expressed by the secretion of T, E2, P4 & 17αOHP. Testosterone was the dominant hormone secreted by cultivated follicular cells, which was correlated closely with the end of vitellogenesis in the isolated oocytes. Decrease in production of these hormones was greater at days 3 & 4 in comparison with those at days 5 & 6. By successfully culturing ovarian follicular cells of Sterlet in L-15 culture medium, an in vitro system was developed which enables functional studies to be carried out similar to the in vivo situation in the ovarian follicles

    A study of affecting factors on the degree of university students loyalty to the brand of nike

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    There are different factors which affect the way people select and continue their attitudes towards products of certain brands. The main objective of the present study was investigating factors affecting the degree of University students’ loyalty  to Nike brand. This research is functional in regard with objective and descriptive-temporary in terms of kind; it was conducted among BA, MA, and PhD student of Physical Education in Tehran University with a sample size of 248 subjects. Researcher-constructed questionnaire, which examined three influential factors (trust, purchase intent, brand image), on the loyalty of University Students, was used to collect data. Research data was analyzed using EM algorithm and Spss software and stepwise multiple regression was applied to investigate the impact of variables on students’ loyalty. Significant regression model showed that all three variables of trust, purchase intent, and brand image had significant effects. Brand trust was the most influential variable with regression coefficient of   0.740 (p<0.001).Based on the results of the present study, the hierarchical priority of three variables, according to students’ replies, was brand trust, purchase intent, and brand image. The results showed that brand trust had the first priority among variables and that Nike brand has managed, on the basis of quality, to satisfy various needs, intentions, and tasks of larger number of university students.Key words: Nike brand, brand trusts, brand image, loyalty, purchase inten

    Utilization of corn gluten meal as a protein source in great sturgeon (Huso huso) diets in growth up stage

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    The utilization of corn gluten meal (CGM) was evaluated as a replacement for fish meal (FM) in practical diets for beluga Huso huso in growth up stage. Four experimental diets (isonitrogenus and isocaloric , 40 % protein and 18 kj/ g diet) were formulated. Fish meal was replaced by CGM at 0%, 20%, 40% and 60% being named as CGM0, CGM20, CGM40 and CGM60, respectively. Fingerlings great sturgeon with an initial body weight of ± 78.876.94gr (mean ±SD) were reared in 12 fiberglass tanks and fed with diets for10 weeks at 20.00± 2 oC. At the end of experiment, growth performance (final weight, body increase weight, specific growth rate) of fish fed CGM20 and CGM40 were significantly higher than fish fed control diet, While feed conversion ratio were lower than fish fed CGM40 and CGM60 compared with control diet. There were not significant difference in condition factor, protein efficiency ratio and body protein in different experimental groups , but body lipid increased as dietary gluten meal increased (P<0.05). Different levels of corn gluten meal did no significantly affect Aspartat amino transferas (AST), Alanin amino transferas (ALT) and Triglyceride, but amount of cholesterol in fish fed diets CGM40 and CGM 60 were significantly lower than control diet (P<0.05). The present study revealed that CGM is a suitable source as replacement with fish meal and might be included in great sturgeon commercial diet up to 60 % with no adverse effect on nutrition efficiency, liver enzymes and biochemical parameters

    Risk-Based Decision Support Model for the Optimal Operation of a Smart Energy Distribution Company for Enabling Emerging Resources

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    In this paper, a risk-based decision support model is developed for a smart energy distribution company, enabling emerging resources like renewable energy sources, electric vehicles and demand response programs in a holistic approach. Because of the inherent uncertainties of these emerging resources, the conditional value-at-risk (CVaR) method is adopted to restrict the distribution company’s risk. A risk aversion parameter sensitivity analysis is also provided on the optimal operation of the smart energy distribution company. The proposed model is thoroughly tested on a 15-bus distribution grid system, and the numerical results prove the effectiveness of the model in risk management

    Researchers Experience Multiple Embodiments in a Cross-Cultural, Intergenerational Event to Support Girls Challenging Gender-Based Violence

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    Many challenges exist to conducting participatory research and consultation with young people, especially with those considered vulnerable or at risk. Beyond respecting the safety and wellbeing of young research participants, researchers must be aware of barriers to youth engagement and be attuned to the many forms of youth resistance. As young people are seeking more control over their lives, traditional knowledge hierarchies between adults and youth are shifting. In July 2018, an event entitled Circles Within Circles brought together Indigenous and non-Indigenous girls and young women from South Africa, Canada, Russia, Sweden, and Kenya to learn from each other’s participatory art-making and create a network for challenging gender-based violence (GBV). This article provides insight into the often-invisible experience of the “supporting cast” in events like Circles Within Circles. The co-authors are doctoral and postdoctoral researchers who contributed to organization and acted as facilitators, notetakers, and participants. The co-authors conduct participatory analyses of journal entries they wrote throughout the event, and jointly reflect on the activities and their feelings about their roles. Reflecting, for example, on gut feelings about young participants’ use of voice and silence during adult-led activities, the co-authors discuss their reading of girls’ demonstrations of resistance. This embodied knowledge, further cultivated by attuning to shared experience, is explored in this collaborative auto-ethnography. Examining the complexities of this cross-cultural and intergenerational event, the co-authors contend that when supporting girls and young people subverting dominant narratives of GBV, researchers’ embodied reflexivity is crucial for positively contributing to girl-led change

    Control Space Reduction and Real-Time Accurate Modeling of Continuum Manipulators Using Ritz and Ritz-Galerkin Methods

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    To address the challenges with real-time accurate modeling of multi-segment continuum manipulators in the presence of significant external and body loads, we introduce a novel series solution for variable-curvature Cosserat rod static and Lagrangian dynamic method. By combining a modified Lagrange polynomial series solution, based on experimental observations, with Ritz and Ritz-Galerkin methods, the infinite modeling state space of a continuum manipulator is minimized to geometrical position of a handful of physical points (in our case two). As a result, a unified easy to implement vector formalism is proposed for the nonlinear impedance and configuration control. We showed that by considering the mechanical effects of highly elastic axial deformation, the model accuracy is increased up to 6%. The proposed model predicts experimental results with 6-8% (4-6 [mm]) mean error for the Ritz-Galerkin method in static cases and 16-20% (12-14 [mm]) mean error for the Ritz method in dynamic cases, in planar and general 3D motions. Comparing to five different models in the literature, our approximate solution is shown to be more accurate with the smallest possible number of modeling states and suitable for real-time modeling, observation and control applications
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