50 research outputs found

    Reproducing The Virginity Imperative: Women’s Collusion and Men’s Complicity Among Young Iranians living in Montreal

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    The present work centres around the question of the virginity imperative, a social contract and regime of power that regulates women’s bodies through disciplinary devices surrounding the socially constructed notion of female virginity. Through participant observation and interviews with young people of Iranian origin residing in Montreal, I explain why the virginity imperative persists among this population. Through description of women’s social navigation (Vigh 2006) of marriage and education, I argue that women’s apparent collusion with restrictive norms does not undermine their agency, but indicates their ability to make decisions that maximize social benefits given their particular circumstances. The argument extends to women’s performance of virginity, which is a face-saving tactic and instrumental in the practice of hypergyny among women I interviewed. Nevertheless, I argue, the virginity imperative operates to categorize women according to a virgin/whore dichotomy, rendering unliveable the lives of those who do not adequately perform virginity. Attitudes that define sex as defiling to women contribute to a gendered politics of knowledge resulting in women’s limited expression of sexuality as compared to men’s, which, along with the patriarchal bargain (Kandiyoti 1988), plays a role in women’s lack of expression of dissent. I argue that men’s preference for virgin women is incompatible with the love marriages they claim to aspire to, and that men lack reflexivity of the consequences for women of attitudes that reinforce the virginity imperative. Bringing an end to these painful consequences requires public discussion to replace their relegation to, and management within, the private sphere

    Intersection-based Piecewise Affine Approximation of Nonlinear Systems

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    This paper presents a new algorithm for PWA approximation of nonlinear systems. Such an approximation is very important to enable a reduction in the complexity of models of nonlinear systems while keeping the global validity of the models. The paper builds on previous work on piecewise affine (PWA) approximation methods, in particular on the work done by Casselman and Rodrigues, known as the Set of Linearization Points (SLP) PWA approximation. The proposed extension method can be used to approximate any continuous function of one variable by a PWA function. The algorithm is based on the points at which the linearization lines intersect with each other. The method assumes that a desired approximation error and one linearization point are given. The algorithm, then performs several linearizations. It is shown that the new linearization points are optimal in the sense of decreasing the error between the exact function and the approximation. The main advantages of this methodology compared to previous approaches are the reduction of the number of pieces of the PWA function, the guarantee that the approximation is continuous, and that the derivative of the approximation and the derivative of the exact function are equal at all linearization points. A detailed collection of examples from different fields of study highlight the effectiveness and the flexibility of the proposed method. It is shown that the proposed method compares favorably with other methods

    The reliability and validity of a designed setup for the assessment of static back extensor force and endurance in older women with and without hyperkyphosis.

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    ObjectiveThe purpose of this study was to investigate the intra-rater reliability and validity of a designed load cell setup for the measurement of back extensor muscle force and endurance.ParticipantsThe study sample included 19 older women with hyperkyphosis, mean age 67.0 Â± 5.0 years, and 14 older women without hyperkyphosis, mean age 63.0 Â± 6.0 years.MethodsMaximum back extensor force and endurance were measured in a sitting position with a designed load cell setup. Tests were performed by the same examiner on two separate days within a 72-hour interval. The intra-rater reliability of the measurements was analyzed using intraclass correlation coefficient (ICC), standard errors of measurement (SEM), and minimal detectable change (MDC). The validity of the setup was determined using Pearson correlation analysis and independent t-test.ResultsUsing our designed load cell, the values of ICC indicated very high reliability of force measurement (hyperkyphosis group: 0.96, normal group: 0.97) and high reliability of endurance measurement (hyperkyphosis group: 0.82, normal group: 0.89). For all tests, the values of SEM and MDC were low in both groups. A significant correlation between two documented forces (load cell force and target force) and significant differences in the muscle force and endurance among the two groups were found.ConclusionThe measurements of static back muscle force and endurance are reliable and valid with our designed setup in older women with and without hyperkyphosis

    Pseudo Euler-Lagrange and Piecewise Affine Control Applied to Surge and Stall in Axial Compressors

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    This thesis addresses the control of the axial compressor surge and stall phenomena using Pseudo Euler-Lagrange and Piecewise Affine (PWA) controller synthesis techniques. These phenomena are considered as major gas turbine compressor instabilities that may result in failures such as the engine flame-out or severe mechanical damages caused by high blade vibration. The common approach towards the detection of the rotating stall and surge is to install various types of pressure sensors, hot wires and velocity probes. The inception of the rotating stall and surge is recognized by the presence of pressure fluctuation and velocity disturbances in the gas stream that are obtained through sensors. The necessary measure is then taken by applying proper stall and surge stabilizing control actions. The Lyapunov stability of pseudo Euler-Lagrange systems in the literature is extended to include additional nonlinear terms. Although Lyapunov stability theory is considered as the cornerstone of analysis of nonlinear systems, the generalization of this energy-based method poses a drawback that makes obtaining a Lyapunov function a difficult task. Therefore, proposing a method for generating a Lyapunov function for the control synthesis problem of a class of nonlinear systems is of potential importance. A systematic Lyapunov-based controller synthesis technique for a class of second order systems is addressed in this thesis. It is shown, in terms of stability characteristics, that the proposed technique provides a more robust solution to the compressor surge suppression problem as compared to the feedback linearization and the backstepping methods. The second contribution is a proposed new PWA approximation algorithm. Such an approximation is very important in reducing the complexity of nonlinear systems models while keeping the global validity of the models. The proposed method builds upon previous work on piecewise affine (PWA) approximation methods, which can be used to approximate continuous functions of n-variables by a PWA function. Having computed the PWA model of the stall and surge equations, the suppression problem is then solved by using PWA synthesis techniques. The proposed solution is shown to have higher damping characteristics as compared to the backstepping nonlinear method

    Effect of laser structured micro patterns on the polyvinyl butyral/oxide/steel interface stability

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    This work investigated the effect of steel substrate topography and roughness on cathodic disbonding resistance and wet adhesion of the polyvinyl butyral/oxide/steel interface. Laser structuring was employed to pattern steel surfaces with controlled, periodic peaks of different peak-to-valley height, Rz, and geometry. Grinded smooth samples were used for reference. The in-situ scanning Kelvin probe technique was used to follow the cathodic disbonding in humid air and wet adhesion loss in inert atmosphere (3 ppm O2_{2}). Both cathodic disbonding and wet adhesion loss depended on the ability of the surface for mechanical adhesion, even when compensating for the increased effective contact area. X-ray photoelectron spectroscopy excluded the possibility for oxide chemistry effects on the delamination rate. Surfaces with features that enabled mechanical interlocking forces, had the best cathodic disbonding resistance and wet adhesion properties

    An Inverse BCC Model for Evaluating and Ordering Decision-Making Units under Fuzziness

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    One of the most ‎prevalent problems in linear programming as one of the convenient models in the field of operation research ‎‎environment is Data Envelopment Analysis (DEA), which supports the ‎efficiency of ‎‎Decision-Making Units (DMUs). Usually, accurate data are common; however, in ‎the real world, we are facing an inaccurate ‎situation. In this paper, a new ‎model for assessing DMUs in a fuzzy environment is presented; we ‎consider the inverse DEA ‎model with the variable return to scale with fuzzy numbers for fluctuating ‎data. A case study is given to ‎illustrate its performance

    Rehabilitative Ultrasound Imaging to Study the Gastrocnemius Muscles Morphology in Patients with Genu Varum and Valgum Deformities

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    Introduction: Genu varum and genu valgum deformities are highly prevalent in Iran. These deformities bring about changes in the structure and function of muscles around the knees. The aim of the present investigation was to study the structure of medial and lateral gastrocnemius muscles in patients with primary genu varum and genu valgum deformities and individuals with normal knee alignment, using rehabilitative ultrasound imaging. Method and Materials: : A Honda 2100 (Honda Co., Japan) real time ultrasound scanner was used in the current the study. The dominant legs of 18 women, 6 with genu varum (mean age: 22.00±1.78 years), 6 with genu valgum (mean age: 21.67±1.03 years), and 6 with normal alignment (mean age: 21.83±1.72 years) were examined. The morphological parameters like muscle thickness, pennation angle and fascicle length of medial and lateral gastrocnemius muscle were compared among groups. Results: In participants with genu varum, the medial gastrocnemius was thinner, closer and shorter in terms of muscle thickness, pennation angle, and fascicle lengths when compared to the lateral gastrocnemius (P<0.05). However, in participants with genu valgum, it was the other way around (P<0.05). In participants with normal alignment, there was no statistically significant difference between the medial and lateral gastrocnemius muscle structures. Conclusions: The rehabilitative ultrasound imaging is highly recommended for studying the structure of gastrocnemius muscle. The structural differences between medial and lateral gastrocnemius muscles may be due to the long term neuromuscular adaptation to knee joint alignment in both genu varum and genu valgum deformities.Key words: Genu, Valgum, Varum, Rehabilitative, Ultrasound, Imagin

    Validity and reliability of the movement assessment battery second edition test in children with and without motor impairment: A prospective cohort study

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    BackgroundExamining the reliability and validity of the second edition movement assessment battery test (MABC-2) in children with and without motor impairment.Materials and methodsIn this prospective cohort study, the MABC-2 test and developmental coordination disorder questionnaire 2007 (DCDQ′07) were completed by children and their parents. By using 95% confidence intervals, minimal detectable change (MDC95) was calculated, and concurrent validity was investigated. By applying the MABC-2 test as a reference standard (cut-off fifth centile), sensitivity and specificity were examined.Results273 children (mean age: 6.3 ± 2.3 years; 70% male) with and without motor impairment completed the investigation. For test-retest reliability, intra-class correlation coefficients (ICCs) was >0.89 for the MABC-2 test. The MDC95 value for the motor skill test was 5.76. There was a significant correlation between the MABC-2 test and DCDQ′07 (r = 0.60, P < 0.001) and the Go/No-Go test (r = 0.50, P < 0.001). Overall, the sensitivity was very high (90%), the specificity was low (46%), and positive and negative predictive values were high (69% and 81%, respectively).ConclusionThe MABC-2 test can be considered a valid and reliable motor skill assessment tool for children with and without motor impairment
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