3,148 research outputs found

    On the Derivation of Vector Radiative Transfer Equation for Polarized Radiative Transport in Graded Index Media

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    Light transport in graded index media follows a curved trajectory determined by the Fermat's principle. Besides the effect of variation of the refractive index on the transport of radiative intensity, the curved ray trajectory will induce geometrical effects on the transport of polarization ellipse. This paper presents a complete derivation of vector radiative transfer equation for polarized radiation transport in absorption, emission and scattering graded index media. The derivation is based on the analysis of the conserved quantities for polarized light transport along curved trajectory and a novel approach. The obtained transfer equation can be considered as a generalization of the classic vector radiative transfer equation that is only valid for uniform refractive index media. Several variant forms of the transport equation are also presented, which include the form for Stokes parameters defined with a fixed reference and the Eulerian forms in the ray coordinate and in several common orthogonal coordinate systems.Comment: This paper has been submitted to JQSR

    THE EFFECT OF ANKLE PLATFORM TRAINING ON ANKLE PROPRIOCEPTION IN SUBJECTS WITH UNILATERAL FUNCTIONAL ANKLE INSTABILITY

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    INTRODUCTION: Functional ankle instability (FAI) is defined as the subjective sensation of giving way or feeling joint instability after repeated episodes of ankle sprain (Riemann et al., 2003). The purpose of this study was to examine the effect of 12-week Biomechanical Ankle Platform System (BAPS) training on ankle reposition sense in subjects with unilateral FAI

    Preparación de sustitutos de grasa de leche humana y mejora de su estabilidad oxidativa

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    1,3-Dioleoyl-2-palmitoylglycerol (OPO) was synthesized by enzymatic interesterification using palm stearin rich in tripalmitin (PPP) and ethyl oleate. Enzymatic interesterification parameters such as temperature, water content, enzyme load, and substrate molar ratio were optimized. High contents of C52 (primarily OPO and its isomeric compounds) production (46.7%) and sn-2 palmitic acid (PA) content of 75.3% were detected. In addition, OPO-human milk fat substitute (HMFS) was blended with coconut, soybean, algal and microbial oils at a weight ratio of 0.70:0.18:0.11:0.004:0.007 to simulate fatty acids in human milk fat (HMF) according to the mathematical model. The main and important fatty acids in the Final-HMFS were within the ranges of those present in HMF. The Final-HMFS could promote the absorption of fats and minerals and the development of retina tissues in infants. The mixture of L-ascorbyl palmitate (L-AP) and vitamin E (VE) resulted in a synergistic antioxidant effect both in OPO-HMFS and OPO-HMFS emulsions. This finding has great significance in improving the quality and extending shelf-life of HMFS.Se sintetizó el 1,3-dioleoil-2-palmitoilglicerol (OPO), utilizando estearina de palma rica en tripalmitina (PPP) y oleato de etilo, mediante interesterificación enzimática. Se optimizaron los parámetros de la interesterificación enzimática, como la temperatura, el contenido de agua, la carga de enzimas y la relación molar del sustrato. Se lograron altos rendimientos de C52 (principalmente OPO y sus isómeros, 46,7%) y un contenido de ácido palmítico (PA) en sn-2 del 75,3%. Además, el sustituto graso de leche humana OPO (HMFS), se mezcló con aceites de coco, soja, algas y microbianos, en una proporción en peso de 0,70:0,18:0,11:0,004:0,007 para simular los ácidos grasos de la leche humana (HMF) de acuerdo con un modelo matemático. Los ácidos grasos principales e importantes en HMFS-Final estaban casi dentro de los rangos de los presentes en HMF. El HMFS-Final podría promover la absorción de grasas y minerales y el desarrollo de los tejidos de la retina en los bebés. La mezcla de palmitato de L-ascorbilo (L-AP) y vitamina E (VE) resultó tener un efecto antioxidante sinérgico, tanto en la emulsión OPO-HMFS como en la OPO-HMFS. Este hallazgo tiene una gran importancia para mejorar la calidad y prolongar la vida útil de HMFS

    THE EFFECT OF ANKLE PLATFORM TRAINING ON ANKLE PROPRIOCEPTION IN SUBJECTS WITH UNILATERAL FUNCTIONAL ANKLE INSTABILITY

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    INTRODUCTION: Functional ankle instability (FAI) is defined as the subjective sensation of giving way or feeling joint instability after repeated episodes of ankle sprain (Riemann et al., 2003). The purpose of this study was to examine the effect of 12-week Biomechanical Ankle Platform System (BAPS) training on ankle reposition sense in subjects with unilateral FAI

    Uniform bounds on the 1-norm of the inverse of lower triangular Toeplitz matrices

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    A uniform bound on the 1-norm is given for the inverse of a lower triangular Toeplitz matrix with non-negative monotonically decreasing entries whose limit is zero. The new bound is sharp under certain specified constraints. This result is then employed to throw light upon a long standing open problem posed by Brunner concerning the convergence of the one-point collocationmethod for the Abel equation. In addition, the recent conjecture of Gauthier et al. is proved

    Towards QoS provisioning in a heterogeneous carrier-grade wireless mesh access networks using unidirectional overlay cells

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    Proceedings of: 6th International ICST Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness, QShine 2009 and 3rd International Workshop on Advanced Architectures and Algorithms for Internet Delivery and Applications, AAA-IDEA 2009, Las Palmas, Gran Canaria, November 23-25, 2009The visibility and success ofWireless Mesh Network (WMN) deployments has raised interest among commercial operators in this technology. Compared to traditional operator access networks WMNs have the potential to offer easier deployment and flexible self-reconfiguration at lower costs. A WMN-type architecture considered as an alternative for an operator access network must meet similar requirements such as high availability and guaranteed QoS in order to support triple-play content provisioning. In this paper we introduce an architecture of such a Carrier-grade Wireless Mesh Access Network (CG-WMAN). We then present our contribution, an approach to seamlessly integrate unidirectional broadcast cells (i.e. DVB-T) into such a CG-WMAN. This allows higher layer protocols to utilize broadcast cells like regular mesh links, where beneficial for a given payload and receiver distribution. We then present a typical use case and discuss for which combinations of traffic type, user distribution and QoS requirements the use of longer range broadcast technologies can help to improve the overall CG-WMAN performance in terms of throughput and reliability.European Community's Seventh Framework ProgramPublicad

    Understanding of hydrogel network formation and its application in the architecture of significantly enhanced hydrogel

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    An understanding of the physical hydrogel network formation has been obtained by dynamic rheological experiments. The evidence shows that the network formation turns out to be a nucleation-controlled process. It was found that there exists a critical temperature Tc; fiber branching is greatly enhanced when the network formation is performed in the regime of T&lt;Tc (T, the final setting temperature). This finding enables the authors to build significantly enhanced gel networks. So far G&prime; (elastic modulus) of the hydrogel network has been enhanced by 187% while the formation period can be greatly shortened to only 1/20 of the previous process.<br /

    Propiedades antioxidantes de dos nuevos derivados lipofílicos del ácido gálico

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    The effectiveness of two lipophilic derivatives of the natural phenol, gallic acid (GA), synthesized using methyl gallate as starting material was investigated. The antioxidant activities of these novel phenolics compared to GA,&nbsp;tert-butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT) were evaluated in bulk oil, emulsion and the DPPH systems. The results showed that the new compounds effectively delayed lipid oxidation much better than GA and other antioxidants under Rancimat (100-140 °C) and emulsion tests. In the bulk oil system at 65 °C, they still behaved better than GA, but TBHQ had the highest activity. Thus, replacing the electron-withdrawing carboxylic group on GA by covalently linking sterically hindered phenols to its phenyl ring increased its lipophilicity and also resulted in synergistic effects which improved overall antioxidant activity through stabilization of the phenoxy radical. These new antioxidant variants satisfy industrial demands for bioactive ingredients with strong antioxidant potentials under different food processing conditions.Se aporta información sobre de la eficacia de dos derivados lipofílicos de fenoles naturales derivados del ácido gálico (GA) y sintetizados utilizando galato de metilo como material de partida. Las actividades antioxidantes de estos nuevos compuestos fenólicos en comparación con el GA, terc-butilhidroquinona (TBHQ) y butil hidroxitolueno (BHT) se evaluaron en aceites, sistemas emulsionados y mediante DPPH. Los resultados mostraron que los nuevos compuestos retrasaron efectivamente la oxidación de lípidos mucho más fuerte que el GA y otros antioxidantes mediante Rancimat (100-140 °C) y pruebas de emulsión. En el aceite a 65 °C, se comportaron mejor que el GA, pero el TBHQ tuvo la actividad más alta. Por lo tanto, reemplazar el grupo carboxílico en GA al unir covalentemente fenoles impedidos estéricamente a su anillo de fenilo ayudó a aumentar su lipofilia y también dio como resultado efectos sinérgicos que mejoraron la actividad antioxidante general a través de la estabilización del radical fenoxi. Estas nuevas variantes de antioxidantes satisfacen la demanda industrial de ingredientes bioactivos con un fuerte potencial antioxidante en diferentes condiciones de procesamiento de alimentos

    Challenges for foreign companies in China: Implications for research and practice

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    As a large country with great development potential, China has been one of the most popular foreign direct investment destinations. However, foreign companies increasingly face a variety of challenges especially during the “soft-landing” of the Chinese economy and amidst anti-globalization tendency. Based on a comprehensive review of the extant literature, we provide a critical overview of some of the key challenges for foreign companies in China, focusing on two challenges related to the business environment, namely regulatory and cultural challenges, and two management challenges, namely innovation and human resource management. We provide managerial implications and outline directions for future research

    POSTURAL STABILITY PERFORMANCE BETWEEN SEDENTARY AND ACTIVE SUBJECTS WITH THE BIODEX STABILITY SYSTEM

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    INTRODUCTION: Postural stability (PS) has been defined as the ability to maintain an upright posture within the base of support (Lee and Lin, 2007) and is considered to be an important indicator of musculoskeletal health and physical performance. This study examined the PS performance between sedentary and active subjects using the Biodex Balance System (BBS) with well intraclass correlation coefficient (Hinman, 2000)
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