3,506 research outputs found

    Relationships of Job and Family Involvement, Family Social Support, and Work–Family Conflict with Job and Life Satisfaction

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    A model of the relationship between work and family that incorporates variables from both the work-family conflict and social support literatures was developed and empirically tested. This model related bidirectional work-family conflict, family instrumental and emotional social support, and job and family involvement to job and life satisfaction. Data came from 163 workers who were living with at least 1 family member. Results suggested that relationships between work and family can have an important effect on job and life satisfaction and that the level of involvement the worker assigns to work and family roles is associated with this relationship. The results also suggested that the relationship between work and family can be simultaneously characterized by conflict and support. Higher levels of work interfering with family predicted lower levels of family emotional and instrumental support. Higher levels of family emotional and instrumental support were associated with lower levels of family interfering with work. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

    Resilience–Recovery Factors in Post-traumatic Stress Disorder Among Female and Male Vietnam Veterans: Hardiness, Postwar Social Support, and Additional Stressful Life Events

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    Structural equation modeling procedures were used to examine relationships among several war zone stressor dimensions, resilience-recovery factors, and post-traumatic stress disorder symptoms in a national sample of 1,632 Vietnam veterans (26% women and 74% men). A 9-factor measurement model was specified on a mixed-gender subsample of the data and then replicated on separate subsamples of female and male veterans. For both genders, the structural models supported strong mediation effects for the intrapersonal resource characteristic of hardiness, postwar structural and functional social support, and additional negative life events in the postwar period. Support for moderator effects or buffering in terms of interactions between war zone stressor level and resiliencerecovery factors was minimal

    Supersonic Crossflow Transition Control in Ground and Flight Tests

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    This paper describes the use of distributed-roughness-element (DRE) patterns along a Mach 2 design swept-wing leading edge to increase the laminar flow extent and thereby reduce drag. One swept-wing model was tested in a supersonic wind tunnel as well as beneath a supersonic flight vehicle. Wing model surface data acquired during these tests included pressures, temperatures, and boundary-layer transition locations. Similarities and differences in experimental results are discussed. While wind tunnel and flight results show some differences, the wind tunnel results still provide key insights necessary for understanding how to design effective DRE patterns for use in flight applications. Experimental results demonstrate a DRE flow control effect observed in flight similar to that observed in the wind tunnel. Finally, a different perspective is discussed concerning what flow control role RE patterns might perform in any future swept-wing laminar flow control applications

    Multi-disciplinary Collaborations in Measurement of Human Motion

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    Comparative Medicine - OneHealth and Comparative Medicine Poster SessionBioengineering is a broad and rapidly-growing discipline defined as the application of engineering principles to biological systems. Although bioengineering is diverse in nature, the study of human movement is common to many bioengineering subdisciplines such as biomechanics and biometrics. Biomechanics is the science that examines the forces acting upon and within a biological structure and effects produced by such forces [1]. Measurement of ground reaction forces, limb motion, and muscle activation are fundamental research components in musculoskeletal biomechanics. Researchers in this field have used these measurements to quantify human gait, balance, and posture in a multitude of applications including age-related fall risk [2-4], muscle fatigue [5-7], and balance-related pathologies such as Parkinson's disease [8-10], and stroke [11, 12]. Additionally, these measurements play a vital role in computational biomechanics models. For example, the inverse dynamics method incorporates measured ground reaction forces and body motions to calculate the net reaction forces and torques acting on body joints [13]. Biometrics is the science of confirming or discovering individuals' identities based on their specific biological or behavioral traits [14]. Gait is one such modality which can be used for biometric identification. It is based on the uniqueness of an individual's locomotion patterns [15]. In addition, we are interested in high-speed video analyses of micro-saccades and blink reflexes for spoof-proofing of biometric identification systems, biometric identification, and psychometry. We have shown that startle blink intensity can be derived from high- speed video [18], enabling video-based psychophysiological biometrics for detection of subject-specific affective-cognitive information [19]. The Human Motion Laboratory at the University of Missouri - Kansas City is dedicated to measuring the characteristics of human motion. The lab includes a VICON MX 6-camera motion capture system, 4 AMTI OR6-6 force platforms, and a Delsys Myomonitor IV 16-channel wireless EMG system. This equipment represents an experimental infrastructure mutually supporting the biomechanics and biometrics research efforts of four research labs. The scope of these research efforts includes aging, affective computing, psychophysiological biometrics, orthopedics, and human dynamics pathology. The lab capitalizes on a synergistic environment for characterization and measurement of human movement and the interrelated nature of the research activities. The four main research areas that the Human Motion Laboratory supports are: •Computational Biomechanics •Biometrics of Human Motion •Experimental Biomechanics •Body Area Sensor Network

    Rodenticidal Effects of Zinc Phosphide and Strychnine of Nontarget Species

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    When three rodenticide treatments—zinc phosphide (prebaited) and strychnine (both with and without prebait)were evaluated, zinc phosphide was the most effective in reducing active burrows of prairie dogs; but, it also resulted in a reduction in deer mouse densities. One month after treatment, counts of fecal pellets of eastern cottontails were greater on areas treated with strychnine without prebait than on sites treated with zinc phosphide. Eight months after treatment, no differences could be detected among rodenticides for either leporid. Horned lark densities were reduced 61% on sites treated with strychnine only

    Crystallinity reduction and enhancement in the chemical reactivity of cellulose by non-dissolving pre-treatment with tetrabutylphosphonium acetate

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    Herein, we demonstrate the activation of commercial chemical cellulose pulps towards chemical modification by a pre-treatment step with tetrabutylphosphonium acetate ([P-4444][OAc]). A heterogeneous (non-dissolving) pre-treatment was applied allowing for a significant reduction in crystallinity, without concomitant formation of the thermodynamically stable cellulose II. An increase in chemical reactivity was demonstrated using two model reactions; (1) acetylation (organic swelling conditions), where high degrees of substitution (DS) were obtained without the need for a catalyst, and (2) 4-acetamido-TEMPO oxidation (aqueous swelling conditions), where significant degrees of oxidation (DO) were obtained, beyond those for the untreated pulps. In both tests a notable improvement in cellulose reactivity was observed. Regioselectivity of acetylation was assessed using 2D NMR for one low and one high DS sample. The low DS showed a small degree of acetylation of the 6-OH, whereas, the high DS from the pre-treated sample showed mainly mixtures of triacetate and diacetates. Important mechanistic information is attained for future development of aqueous and organic-based reactions involving this ionic liquid pre-treatment.Peer reviewe

    Rodenticidal Effects of Zinc Phosphide and Strychnine of Nontarget Species

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    When three rodenticide treatments—zinc phosphide (prebaited) and strychnine (both with and without prebait)were evaluated, zinc phosphide was the most effective in reducing active burrows of prairie dogs; but, it also resulted in a reduction in deer mouse densities. One month after treatment, counts of fecal pellets of eastern cottontails were greater on areas treated with strychnine without prebait than on sites treated with zinc phosphide. Eight months after treatment, no differences could be detected among rodenticides for either leporid. Horned lark densities were reduced 61% on sites treated with strychnine only

    Piezo-Polymer-Composite Unimorph Actuators for Active Cancellation of Flow Instabilities Across Airfoils

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.This article presents a smart device for active cancellation of flow instabilities. An array of two piezo unimorph actuators fabricated in piezo-polymer-composite technology is combined with a thin silicone membrane to mimic a movable wall with a closed surface. By locally displacing the thin membrane, a surface wave is generated that interferes with naturally occurring flow instabilities within the boundary layer of an airfoil. Using flow sensors and an intelligent control enables a destructive interference and therefore, an attenuation of natural flow instabilities. This leads to a delay of transition. The boundary layer remains laminar which means drag is reduced. Within the next pages, the setup of the device with actuators, membrane, sensors, and control is introduced. The main focus of this article is on actuator design, modeling, and implementation for wind tunnel experiments. Results of actuator characterization are presented. The non-linear behavior of the piezoactuator (harmonic distortions and impact of high electric fields) is investigated in detail. This study concludes with the results obtained in wind tunnel experiments which prove the functionality of the presented approach. A maximal attenuation of natural occurring flow instabilities of 80% is achieved.DFG, SPP 1207, Strömungsbeeinflussung in der Natur und Techni
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