365 research outputs found

    Effects of Local and Nonlocal Substructure Spin on Localization in Tantalum Top-Hat Specimen

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    Effects of local and nonlocal substructure spin on the localization behavior of tantalum top-hat specimens subjected to high-rate compression are investigated. The orientation of a quadratic yield surface within the space of the intermediate configuration second Piola Kirchhoff stress is defined by a triad of substructure unit director vectors. Local evolution kinetics for the substructure directors are based on a plastic constitutive spin proportional to the non-coaxiality between stress and plastic rate of deformation within the spinless intermediate configuration. An extension of the local plastic constitutive spin to reflect nonlocal kinetics is made by attenuating or amplifying the spin rate depending on the misorientation of the substructure directors at a material point with those at adjacent material points within some neighborhood. Increased local spin rates tend to accentuate localization of plastic deformation and acts as a constitutive softening mechanism. On the other hand, the constraint imposed by nonlocal evolution of substructure orientation affects the plastic deformation field by reducing the propensity for flow, thus delaying localization and increasing the spatial coherence of the director vector field

    Organizational climate and employee mental health outcomes: A systematic review of studies in health care organizations

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    __Abstract__ Background: In recent years, the high prevalence of mental health problems among health care workers has given rise to great concern. The academic literature suggests that employees’ perceptions of their work environment can play a role in explaining mental health outcomes. Purposes: We conducted a systematic review of the literature in order to answer the following two research questions: (1) how does organizational climate relate to mental health outcomes among employees working in health care organizations and (2) which organizational climate dimension is most strongly related to mental health outcomes among employees working in health care organizations. Methodology/Approach: Four search strategies plus inclusion and quality assessment criteria were applied to identify and select eligible studies. As a result, 21 studies were included in the review. Data were extracted from the studies to create a findings database. The contents of the studies were analyzed and categorized according to common characteristics. Findings: Perceptions of a good organizational climate were significantly associated with positive employee mental health outcomes such as lower levels of burnout, depression, and anxiety. More specifically, our findings indicate that group relationships between co-workers are very important in explaining the mental health of health care workers. There is also evidence that aspects of leadership and supervision affect mental health outcomes. Relationships between communication, or participation, and mental health outcomes were less clear. Practical Implications: If health care organizations want to address mental

    Organisatieklimaat en geestelijke gezondheid van medewerkers

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    Dat geluk ook te maken heeft met gezondheid, is in een groot aantal wetenschappelijke onderzoeken bewezen. Hoewel mensen met een zorgberoep behoren tot een van de beroepsgroepen waarin het meeste geluk wordt ervaren, groeit de aandacht voor het voorkómen van geestelijke gezondheidsproblemen onder zorgmedewerkers. Uit de wetenschappelijke literatuur over dit onderwerp blijkt dat de perceptie die medewerkers hebben van hun werkomgeving een belangrijke rol speelt in hun geestelijke gezondheid. Om dit nader te onderzoeken, zijn de volgende onderzoeksvragen geformuleerd. Ten eerste: hoe is het organisatieklimaat binnen zorgorganisaties gerelateerd aan de geestelijke gezondheid van medewerkers? En ten tweede: welke dimensie van organisatieklimaat is het sterkst gerelateerd aan de geestelijke gezondheid van zorgmedewerkers? Om deze vragen te beantwoorden, is er een overzichtsstudie uitgevoerd. De resultaten laten zien dat percepties van een goed organisatieklimaat significant samenhangen met positieve geestelijke gezondheidsuitkomsten (zoals minder burn-out, depressie en ang

    Large scale analysis of expressed genes in common wheat

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    To assess associations between occlusal tooth wear and shortened dental arches (SDA) in Chinese 40 years and older subjects. From a sample of 1462 urban and rural adults, those presenting with SDA (n = 150) were compared with a control group of 65 randomly selected subjects with complete dentitions (CDA). Occlusal wear was assessed using a modified Smith and Knight index - the occlusal tooth wear index (OWTI) - and analysed using multivariate (logistic) regression. There was no significant effect from SDA on severe occlusal wear (OTWI score 3 or 4: OR = 2.016; 95% CI = 0.960-4.231; P = 0.064). Higher age was associated with severe occlusal wear (P values </=0.007) and with higher mean OTWI scores; urban had less often severe occlusal wear than rural residents (OR = 0.519; P = 0.008). Higher mean OTWI scores were associated with rural residents, except for anterior teeth. Females had lower mean OTWI score for anterior teeth (effect = -0.153; P = 0.030). Premolars in SDA had higher mean OTWI scores compared with those in CDA (effect = +0.213; P = 0.006). In SDA, more posterior occluding pairs (POPs) were associated with lower mean OTWI sores for anterior teeth (effect: -0.158; P = 0.008) and higher scores for molars (effect: +0.249, P = 0.003). Subjects with SDA or CDA presented comparable occlusal wear, but premolars in SDA tend to have higher probability for having occlusal wear. Fewer numbers of POPs were associated with more wear in anterior teeth

    Dental Status and Associated Factors in a Dentate Adult Population in Bulgaria: A Cross-Sectional Survey

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    This study aimed to determine variations in the dental status of a dentate adult population in terms of “decayed,” “missing,” and “filled” teeth in relation to several sociodemographic and behavioral factors. Quota sampling was used to draw 2531 subjects aged 20 years and over. Data were collected by means of a questionnaire and an oral examination. Multiple logistic regression analyses were performed to observe associations between “decayed,” “missing,” and “filled” teeth and the factors of interest. The mean numbers of “decayed,” “missing,” and “filled” teeth were 2.2, 6.7, and 4.9, respectively. Molar teeth were significantly more often “missing” than premolar and anterior teeth. Age, gender, education, and tooth brushing revealed most noticeable associations. Increasing age was associated with a lower chance of having “decayed” and “filled” teeth, but with a higher chance of having “missing” teeth. Females were more likely to have “missing” and “filled” teeth. Higher education was associated with a lower chance of having “missing” teeth. More frequent tooth brushing was associated with a lower chance of having “decayed” and “missing” teeth, but with a higher chance of having “filled” teeth. These risk indicators should be considered in prevention program planning if reduction of tooth loss is to be achieved

    Euler buckling in red blood cells: An optically driven biological micromotor

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    We investigate the physics of an optically-driven micromotor of biological origin. A single, live red blood cell, when placed in an optical trap folds into a rod-like shape. If the trapping laser beam is circularly polarized, the folded RBC rotates. A model based on the concept of buckling instabilities captures the folding phenomenon; the rotation of the cell is simply understood using the Poincar\`e sphere. Our model predicts that (i) at a critical intensity of the trapping beam the RBC shape undergoes large fluctuations and (ii) the torque is proportional to the intensity of the laser beam. These predictions have been tested experimentally. We suggest a possible mechanism for emergence of birefringent properties in the RBC in the folded state
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