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51.
The way we learn has changed dramatically in the new millennium. The introduction of e-learning in higher education in the late 1990s has opened Pandora's Box, and brought radical changes in the way where undergraduate and postgraduate programs are designed and delivered. The rapid developments and popularity ofhandheld devices such as smart phones and tablet PCs using wireless networks and mobile Intemet have marked new developments in higher education, introducing the so-called mobile leaming (m-learning). This means that university students can have access to their studies related content, anytime, anywhere in a personalized manner; this is what renders m-learning so popular and fashionable among university students globally. Nevertheless, instructors are now challenged as they have to adopt new pedagogies in learning and teaching. This paper discusses the concept of m-learning, as well as the current developments and challenges related to the major stakeholders (educators and students) in higher education. 相似文献
52.
Evangelia Kokolaki Merkouris Karaliopoulos Ioannis Stavrakakis 《Pervasive and Mobile Computing》2012,8(2):210-227
In this paper, we explore the way the discovery of service can be facilitated or not by utilizing service location information that is opportunistically disseminated primarily by the service consumers themselves. We apply our study to the real-world case of parking service in busy city areas. As the vehicles drive around the area, they opportunistically collect and share with each other information on the location and status of each parking spot they encounter. This opportunistically assisted scenario is compared against one that implements a “blind” non-assisted search and a centralized approach, where the allocation of parking spots is managed by a central server with global knowledge about the parking space availability.Results obtained for both uniformly distributed travel destinations and a single hotspot destination reveal that the relative performance of the three solutions can vary significantly and not always inline with intuition. Under the hotspot scenario, the opportunistic system is consistently outperformed by the centralized system, which yields the minimum times and distances at the expense of more distant parking spot assignments; whereas, for uniformly distributed destinations, the relative performance of all three schemes changes with the vehicle volume, with the centralized approach gradually becoming the worst solution and the opportunistic one emerging as the best scheme. We discuss how each approach modulates the information dissemination process in space and time and resolves the competition for the parking resources. We also outline models providing analytical insights to the behaviour of the centralized approach. 相似文献
53.
Ksinopoulou Evangelia Dragatogiannis Dimitrios Bakolas Asterios Charitidis Constantinos Moropoulou Antonia 《Journal of Polymer Research》2022,29(5):1-15
Journal of Polymer Research - Sodium 2,2′-methylene-bis(4,6-di-tertbutylphenyl)-phosphate (NA11) is an α-type nucleating agent for improving the mechanical and crystallization... 相似文献
54.
55.
Limiting heat losses during ventilation of indoor building spaces has become a basic aim for architects, particularly since the oil crisis of 1970. Much experience has been gained in terms of ventilation of indoor spaces. Nevertheless, due to the complex applications, attempts to create a theoretical base for solving the problems related to the issue are limited, especially determining the minimum ventilation period required within a designated space. In this paper we have approached this matter, both theoretically and experimentally. The conclusion we reached was that controlled ventilation of spaces through vent holes that successively open and close at regular time intervals can limit the excessive circulation of air masses, which in turn limits heat losses. 相似文献
56.
Xanthopoulou Despoina; Baker Arnold B.; Heuven Ellen; Demerouti Evangelia; Schaufeli Wilmar B. 《Canadian Metallurgical Quarterly》2008,13(4):345
This study aims to gain insight in the motivational process of the Job Demands-Resources (JD-R) model by examining whether daily fluctuations in colleague support (i.e., a typical job resource) predict day-levels of job performance through self-efficacy and work engagement. Forty-four flight attendants filled in a questionnaire and a diary booklet before and after consecutive flights to three intercontinental destinations. Results of multilevel analyses revealed that colleague support had unique positive effects on self-efficacy and work engagement. Self-efficacy did not mediate the relationship between support and engagement, but work engagement mediated the relationship between self-efficacy and (in-role and extra-role) performance. In addition, colleague support had an indirect effect on in-role performance through work engagement. These findings shed light on the motivational process as outlined in the JD-R model, and suggest that colleague support is an important job resource for flight attendants helping them reach their work-related goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
57.
Ioannis S. Arvanitoyannis Ebrahim M. Khah Evangelia C. Christakou & Fotios A Bletsos 《International Journal of Food Science & Technology》2005,40(3):311-322
The physico‐chemical parameters (pH, mechanical firmness and vitamin C) and sensory parameters of grafted and ungrafted eggplant plants were studied in relation to storage time (up to 17 days at 10 °C). Eggplant plants of cultivar ‘Tsakoniki’ were grafted on Solanum torvum and S. sisymbriifolium rootstocks in order to avoid the soil borne disease caused by Verticillium dahliae. The fruits were stored under modified atmosphere packaging (MAP). Vitamin C was negatively affected by grafting it storage, while MAP prolonged the shelf life. Although pH was not affected by grafting but was positively affected by MAP. Flesh firmness was negatively affected by grafting and reduced over storage, but positively affected by MAP. Sensory analysis showed higher ratings of fruits from ungrafted plants for sweetness, acceptance and hardness whereas no difference was detected for overall acceptance. Fruits stored under MAP were better maintained compared with those stored in air. 相似文献
58.
Niki Mourtzi Amalia Sertedaki Evangelia Charmandari 《International journal of molecular sciences》2021,22(11)
Stress is defined as a state of threatened or perceived as threatened homeostasis. The well-tuned coordination of the stress response system is necessary for an organism to respond to external or internal stressors and re-establish homeostasis. Glucocorticoid hormones are the main effectors of stress response and aberrant glucocorticoid signaling has been associated with an increased risk for psychiatric and mood disorders, including schizophrenia, post-traumatic stress disorder and depression. Emerging evidence suggests that life-stress experiences can alter the epigenetic landscape and impact the function of genes involved in the regulation of stress response. More importantly, epigenetic changes induced by stressors persist over time, leading to increased susceptibility for a number of stress-related disorders. In this review, we discuss the role of glucocorticoids in the regulation of stress response, the mechanism through which stressful experiences can become biologically embedded through epigenetic alterations, and we underline potential associations between epigenetic changes and the development of stress-related disorders. 相似文献
59.
Problem-solving theories have not examined how solvers navigate their knowledge to interpret problem situations or to plan strategies toward goals. In this article, the author argues that success in problem solving depends on the solver's ability to construct goal-derived categories, namely categories that are formed ad hoc to serve goals during the instantiation of problem frames. Experiment 1 (N = 140) showed improved problem-solving performance after training to construct goal-derived categories. Experiment 2 (N = 80) demonstrated that effects of training in category construction can be obtained without participants being explicitly informed regarding the relevance of training to problem solving. These studies suggest that problem solving is a dynamic expression of goal-directed cognition and provide evidence for the involvement of categorization in problem-solving processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
Nefta-Eleftheria P. Votsi Evangelia G. Drakou Antonios D. Mazaris 《Landscape and urban planning》2012,104(2):279-288
The need to preserve natural quietness, as a resourceful land protection strategy, has increased with the need to implement the EU's Environmental Noise Directive (END, 2002/49/EC) at a national level. We implemented distance-based criteria with view to defining potential Quiet Areas (QAs) in open country of Greece.Residential areas, industrial sites and traffic noise are the main environmental noise sources considered according to END's prerequisites. Also following the particular characteristics of the country (e.g. leisure facilities) we considered recreational areas and construction sites for our analysis, as well as the cumulative effects of noise sources. The spatial analysis of QAs in open country indicated that the higher values of clustering are found in places of high biodiversity value (as these were characterized by the Habitat's Directive 92/43/EEC), thus multiplying the need for QAs to be preserved.Although distance-based criteria are considerably less accurate than true noise levels calculations, our research serves as a first step for the estimation of QAs in open country at the national level, before moving on to on-site measurements for the complete definition of QAs (at the regional level), thus providing a rapid, comprehensible but above all a cost-effective solution for the assessment of QAs by management responsibles. 相似文献