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661.
A great number of teachers find teaching fulfilling and are dedicated to it, but others feel emotionally exhausted, indicating that the interaction with pupils can be emotionally demanding. Emotional labor was shown to play an important role for the health of teachers. In a full two-wave longitudinal study over the period of 1 year, the effect of emotional labor on emotional exhaustion and dedication of 102 teachers was investigated. Teachers who were able to influence their emotions to feel the emotion appropriate in a situation (so called deep acting) felt significantly less emotionally exhausted after 1 year. From this result, deep acting can, thus, be characterized as health-beneficial. Once teachers felt emotionally exhausted, they used more surface acting. More dedicated teachers, on the contrary, did neither engage more in deep acting nor in surface acting at Time 2. This indicates that those teachers who are dedicated to teaching seem less likely to act. To prevent emotional exhaustion of teachers, the development of interventions to promote health-beneficial emotional labor is necessary. This can be achieved by fostering deep acting, which reduces emotional exhaustion over longer periods of time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
662.

Virtual reality (VR) has become popular in mental health research. Several studies have explored the use of VR in the context of biofeedback protocols. In the present paper, we report on the development and evaluation of a VR-based respiratory biofeedback game to foster diaphragmatic breathing. The game integrates respiratory biofeedback, restorative VR and gamification. The game is designed to run on a mobile, all-in-one VR headset. Notably, an integrated VR hand controller is utilized as a sensor to detect respiration-induced movements of the diaphragm. In a longitudinal within-subjects study, we explored the feasibility of the game and tested the effectiveness of six training sessions. Participants reported a pleasant user experience. Moreover, the results show that the brief VR-based breathing training increased perceived breath awareness, improved diaphragmatic breathing, increased relaxation, decreased perceived stress, reduced symptoms of burnout and boosted relaxation-related self-efficacy. Future studies need to address the generalizability and long-term stability of the results, compare the approach with existing treatments and fine-tune the training components.

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663.
Information systems development (ISD) is analysed in this paper as asystemic work activity, using Activity Analysis and Development (ActAD)as the theoretical framework. ISD is regarded here as the process bywhich some collective work activity is facilitated by newinformation-technological means through analysis, design, implementation,introduction and sustained support, as well as process management. Itis a temporary, boundary-crossing activity which draws its actors,means, rules, etc. from two sides – typically a software companyand the IS user organization. ISD is analysed as a part of a networkof activities, too, around software development and a computer-supporteduse activity. A theoretical framework and a pragmatic checklist arepresented for studying ISD activities. It is argued that the activity-theoretical framework provides a theoretically foundedbut detailed and practicable procedure for studying ISD as a workactivity in context.  相似文献   
664.
This article reports on two user studies investigating the effect of visual context in handheld augmented reality interfaces. A dynamic peephole interface (without visual context beyond the device display) was compared to a magic lens interface (with video see-through augmentation of external visual context). The task was to explore items on a map and look for a specific attribute. We tested different sizes of visual context as well as different numbers of items per area, i.e. different item densities. Hand motion patterns and eye movements were recorded. We found that visual context is most effective for sparsely distributed items and gets less helpful with increasing item density. User performance in the magic lens case is generally better than in the dynamic peephole case, but approaches the performance of the latter the more densely the items are spaced. In all conditions, subjective feedback indicates that participants generally prefer visual context over the lack thereof. The insights gained from this study are relevant for designers of mobile AR and dynamic peephole interfaces, involving spatially tracked personal displays or combined personal and public displays, by suggesting when to use visual context.  相似文献   
665.
We present an empirical study of an organization that has recently moved from traditional newspaper production towards cross-media production involving the integrated digital production of newspaper, television, radio and web-news. The paper focuses on the daily production rhythms of the media separately and of cross-media production. Since cross-media production is in the making, we study the instruments currently used for planning and coordination, and analyze them as seeds that will eventually make cross-media production happen. Time and timing are important in news production in general, and our analyses focus on the rhythm of the daily planning, coordination and production processes. Specifically, we analyze the temporal coordination of the activities in and around the Superdesk – the current center of coordination of the news organization, and of the persons who work specifically with planning and coordination. We demonstrate how the production rhythms of the individual media collide with that of cross-media, and how product lifecycle rhythms add to the list of causes of problems that may jeopardize cross-media production. We propose to strengthen planning and overview support elements of the Superdesk, and the main new coordinator role of the organization. We point out how the media rhythms of newspaper in particular must be backgrounded. To achieve cross-media production, the starting point must be to strengthening and developing further the cross-media rhythms, rather than supplementing individual media rhythms.
Anja Bechmann PetersenEmail:
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666.
We study the computational complexity of the existence and the verification problem for wonderfully stable partitions (WSPE and WSPV) and of the existence problem for strictly core stable coalition structures (SCSCS) in enemy-oriented hedonic games. In this note, we show that WSPV is NP-complete and both WSPE and SCSCS are DP-hard, where DP is the second level of the boolean hierarchy, and we discuss an approach for classifying the latter two problems in terms of their complexity.  相似文献   
667.
The strength and E-modulus of concrete are decisive parameters when it comes to ultimate limit state design, serviceability limit state design, and early age crack assessment. The properties of concrete are generally determined in the laboratory under 20 °C isothermal conditions and then used as the basis for calculations under realistic temperature conditions. It is well-known, however, that the curing temperature affects both the rate of property development in concrete and the “final value” of a given property. The current study investigated the effect of a realistic temperature history on the compressive cube strength, the tensile strength, and the tensile E-modulus for two concretes, a reference concrete and a fly ash concrete. Concrete specimens were subjected to either (1) 20 °C isothermal curing conditions, or (2) realistic temperature curing conditions for 14 days and then 20 °C isothermal conditions, until they were tested after 28 and 91 days. Parallel tests performed in a Temperature-Stress Testing Machine were also used to evaluate the results. The reference concrete showed a general reduction in strength and E-modulus when subjected to a realistic curing temperature, whereas the fly ash concrete showed an 11% increase in the 28-day E-modulus when cured under realistic temperature conditions. Furthermore, in both isothermal and realistic curing temperature conditions, the fly ash concrete showed a pronounced property development beyond 28 days, which could not be described by the material model currently used.  相似文献   
668.
Plasma nitriding of aluminum alloys is a suitable method for improving wear resistance because of the hard ceramic AlN layer formed. However, the surface's load‐bearing behavior is greatly limited by the low hardness of the Al base material. New investigations regarding improved load support of the thin AlN layer examine the treatment sequence of nitriding and subsequent EB remelting. Because of its broad range of beneficial alloying elements (Si, Fe, Cu, Mg), a hypereutectic Al–Si alloy (DISPAL® S232) ? made by spray forming ? was used as the base material. The electron beam remelting process is carried out on samples with a nitride layer thickness of approx. 3 μm. As a result of the newly formed phases, grain refinement, and oversaturation of the aluminum solid solution, the surface hardness beneath the nitride layer can be increased by up to three times compared to that of the initial base material. The estimated enhancement in load support is evaluated by unlubricated wear tests using a pin‐on‐disc configuration and scratch tests under constant loading conditions. Furthermore, the wear mechanisms are investigated by means of detailed SEM examination of the remelted surface layer.
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669.
In order to mimic cell organelles, artificial nanoreactors have been investigated based on polymeric vesicles with reconstituted channel proteins (outer membrane protein F) and coencapsulated enzymes horseradish peroxidase (HRP) along with a crowding agent (Ficoll or polyethylene glycol) inside the cavity. Importantly, the presence of macromolecules has a strong impact on the enzyme kinetics, but no influence on the integrity of vesicles up to certain concentrations. This particular design allows for the first time the determination of HRP kinetics inside nanoreactors with crowded milieu. The values of the Michaelis–Menten constant (K m) measured for HRP in a confined space (encapsulated in nanoreactors) in the absence of macromolecules are ≈50% lower than in free conditions, and the presence of a crowding agent results in a further pronounced decrease. These results clearly suggest that activities of enzymes in confined spaces can be tuned by varying the concentrations of crowding compounds. The present investigation represents an advance in nanoreactor design by considering the influence of environmental factors on enzymatic performance, and it demonstrates that both encapsulation and the presence of a crowding environment increase the enzyme‐substrate affinity.  相似文献   
670.
One key point for improving osseous integration of implants is to render them osteopromotive by specifically favoring the adhesion of osteoblasts. Mimicking the physiological adhesion process of osteoblasts to the extracellular matrix improves cell adhesion in vitro and results in improved and earlier osseous integration of implants in vivo. Our approach involves coating titanium implants with a tailor-made cyclic-RGD peptide, thus allowing them to bind to specific integrin receptors on the cell surface through multimeric phosphonates. The advantages of this very stable, new type of anchoring for practical application are presented.  相似文献   
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