87 research outputs found

    Triangulated Surfaces in Twistor Space: A Kinematical Set up for Open/Closed String Duality

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    We exploit the properties of the three-dimensional hyperbolic space to discuss a simplicial setting for open/closed string duality based on (random) Regge triangulations decorated with null twistorial fields. We explicitly show that the twistorial N-points function, describing Dirichlet correlations over the moduli space of open N-bordered genus g surfaces, is naturally mapped into the Witten-Kontsevich intersection theory over the moduli space of N-pointed closed Riemann surfaces of the same genus. We also discuss various aspects of the geometrical setting which connects this model to PSL(2,C) Chern-Simons theory.Comment: 35 pages, references added, slightly revised introductio

    Quantum curves for Hitchin fibrations and the Eynard-Orantin theory

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    We generalize the topological recursion of Eynard-Orantin (2007) to the family of spectral curves of Hitchin fibrations. A spectral curve in the topological recursion, which is defined to be a complex plane curve, is replaced with a generic curve in the cotangent bundle TCT^*C of an arbitrary smooth base curve CC. We then prove that these spectral curves are quantizable, using the new formalism. More precisely, we construct the canonical generators of the formal \hbar-deformation family of DD-modules over an arbitrary projective algebraic curve CC of genus greater than 11, from the geometry of a prescribed family of smooth Hitchin spectral curves associated with the SL(2,C)SL(2,\mathbb{C})-character variety of the fundamental group π1(C)\pi_1(C). We show that the semi-classical limit through the WKB approximation of these \hbar-deformed DD-modules recovers the initial family of Hitchin spectral curves.Comment: 34 page

    Models for length back-calculation in Caspian Kutum, Rutilus kutum (Pisces: Cyprinidae) from the Caspian Sea

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    The Caspian Kutum, Rutilus Kutum (Kamensky 1901) specimens were sampled by purse seine in the northern Iranian coast of the Caspian Sea at four locations: Feridoonkenar Shahed, Mahmoudabad Khoram, Lariim Azadi fishing coop, and the Shiroud River in Ramsar city. “Back-calculation” is a retrospective method of estimating the characteristics of growth of fish in terms of length and rate of growth in the years preceding capture. Backcalculation of fish lengths at previous ages from scales or otoliths is a widely used approach to estimate both individual and population growth history. The back-calculated lengths of the Caspian kutum, Rutilus kutum (Kamensky 1901) were obtained using six different models, namely scale proportional hypothesis, body proportional hypothesis, Fraser Lee, nonlinear scale proportional hypothesis, nonlinear body proportional hypothesis, and the newest method, Morita Matsuishi model. The results showed that the preferred backcalculation models is Fraser Lee model for both males and females, while the nonlinear body proportional hypothesis is only for the females

    Validity and Reliability of the Persian Version of the Food Thought Suppression Inventory for Obese University Students

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    Objectives: To determine the validity and reliability of the Persian version of the Food Thought Suppression Inventory (FTSI) in overweight university students in Iran. Methods: A sample of 233 overweight students were recruited from five universities in Tehran. Participants were asked to complete the Persian versions of FTSI, Binge Eating Scale, Thought Control Questionnaire, Rumination Response Scale, and Dutch Eating Behaviour Questionnaire. Sociodemographic characteristics of participants were also collected. Results: Validity of the Persian version of the FTSI was verified by the fitting indices of the proposed single-factor model of the main makers (Χ2= 112.75, df = 90, p = 0.052, Χ2/df = 1.25, goodness-of-fit index = 0.93, comparative fit index = 0.96, non-normed fitness index = 0.96, root mean score of error approximation = 0.032, and standardised root mean residual = 0.052). Internal consistency of the instrument was high, with a Cronbach's alpha of 0.88. Conclusion: The Persian version of the FTSI is a valid and reliable tool for screening patients in obesity clinics and for evaluating treatment outcomes. © 2020 Hong Kong Academy of Medicine Press. All rights reserved

    Effect of controlled and uncontrolled cooling rate on motility parameters of cryopreserved ram spermatozoa

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    <p>Abstract</p> <p>Background</p> <p>Ram spermatozoa are sensitive to extreme changes in temperature during the freeze-thaw process. The degree of damage depends on a combined effect of various factors including freezing temperature. The aim of this study was to determine the effects of two cooling method (controlled-rate and uncontrolled-rate) on pre-freezing and post-thaw sperm motility parameters.</p> <p>Results</p> <p>Ejaculates were collected using the artificial vagina from four Chal rams and three replicates of the ejaculates were diluted with a Tris-based extender and packed in 0.25 ml straws. Then, sample processed according to the two methods. Method 1: straws cooled from 37 to 5°C, at a liner rate of -0.3°C/min in a controlled-rate cooling machine (custom-built) and equilibrated at 5°C for 80 min, then the straws were frozen at rate of -0.3°C/min from 5°C to -10°C and -25°C/min from -10°C to -150°C and plunged into liquid nitrogen for storage. Method 2: straws were transferred to refrigerator and maintained at 5°C for 3 h, then the straws were frozen in liquid nitrogen vapor, 4 cm above the liquid nitrogen for 15 min and plunged into liquid nitrogen. Computer-assisted sperm motility analysis was used to analyze sperm motion characteristics.</p> <p>Conclusions</p> <p>Controlled rate of freezing (Method 1) significantly improve the pre-freezing and post-thaw total and progressive motility compared to uncontrolled rate (Method 2). In specific kinetic parameters, Method 1 gives significantly higher value for VSL and VCL in comparison with Method 2. There are no significant differences between the two methods for VAP and LIN. In conclusion, controlled rate of cooling conferred better cryopreserving ability to ram spermatozoa compared to uncontrolled rate of cooling prior to programmable freezing.</p

    Non-Invasive Prosthetic Hand Model

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    Prosthetics are artificial devices that replace a missing body part, which may be lost through, disease, accidents or combat in times of warfare. The exponential advances in microprocessor technology coupled with affordability have spawned an online support community that have incorporated cost-effective microcontrollers in interesting applications. In relation to prosthetics, scientists and engineers frequent drawing boards periodically to update prosthetic design, each time incorporating more features that are increasingly less noticeable to the user. However, strict standards for medical devices and demand for reliability mean very few implementations have progressed from research and development phases to production for the commercial sector. The scientific community has been working diligently on this frontier for decades but it is still considered an open problem needing to be solved. Even though many breakthroughs are likely to occur within the next decade, the likelihood of cost effective implementation from large-scale research projects is slim meaning most amputees will not be able to afford this technology. This research is focused on the implementation a prototype of a non-invasive prosthetic hand model replicated by a robotic hand. Electromyography is the study of electrical signals produced by the movement of muscles in the human body .The prototype will be designed to use pre-processed electromyography signals as control signals in order to demonstrate replication of simple hand movements. This research project will be completed by first examining pre-processed electromyography signals identified that trigger specific hand movements and then programming microcontrollers to recognize these signals, which leads to ultimately replicating hand movements by controlling the servo motors of a robotic hand. The effective combination of hardware and software has yet to be determined. This research benefits society because it will provide insight to using cost effective hardware as a basis for prosthetic limb control thus allowing future products in the commercial sector to benefit from these savings

    Extensive Proliferation of Cd4+ Lymphocyte by Both Phytohaemagglutinin A and Anti-Cd2/Cd3/ Cd28 Macsibeads

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    Background: Lymphocytes proliferate considerably following appropriate stimulation in vitro. Autologous T cells are obtained from whole blood or tissue sites in relatively limited amounts. We need a method to expand these cells efficiently, study their functions and manipulate them to create appropriate cells for transferring to the patient with infection and cancer. Objectives: The aim of this study is to determine proliferation ability of two different stimulators on CD4+ lymphocytes. Methods: Lymphocytes were isolated from blood samples of healthy donors after removing adherent cells (monocytes).The efficacy of MACSiBead™ coated with anti-CD2, anti-CD3, anti-CD28 (anti-CD2/CD3/CD28) was compared with Phytohaemagglutinin A (PHA) on CD4+ lymphocytes proliferation using carboxyfluorescein diacetate succinimidyl ester (CFSE) in cell culture media. The percentage of proliferating cells was analyzed using flow cytometry. Results: Both stimulators induced extensive proliferation of CD4+ lymphocytes but proliferation ability of PHA was higher compared to stimulation by anti-CD2/CD3/CD28 MACSiBead™. The proliferation rate of cells stimulated by PHA was 93.8% ± 3.37% whereas it was 85.2% ± 4.7% in cells stimulated by anti-CD2/CD3/CD28 MACSiBead™. Conclusions: Our results show that MACSiBead™ along with PHA can be used to obtain a large number of expanded CD4+ lymphocytes
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