471 research outputs found

    An investigation of small-scale motions and the forecasting of wind profiles over short periods of time at Cape Kennedy, Florida

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    Small scale motions and numerical wind profiles forecasting for short periods at Cape Kenned

    Gravitational Force and the Cardiovascular System

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    Cardiovascular responses to changes in gravitational force are considered. Man is ideally suited to his 1-g environment. Although cardiovascular adjustments are required to accommodate to postural changes and exercise, these are fully accomplished for short periods (min). More challenging stresses are those of short-term microgravity (h) and long-term microgravity (days) and of gravitational forces greater than that of Earth. The latter can be simulated in the laboratory and quantitative studies can be conducted

    Imagine being off-the-grid: Millennials' Perceptions of Digital-Free Travel

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    The blurred boundaries between home and away facilitated by the ubiquitous connectivity have resulted in restlessness in private life, even on holiday. Disconnecting from technology on holiday could potentially contribute to travellers’ psychological sustainability. This article aims to theorise the perceptions of millennials towards digital-free travel (DFT). We interviewed 17 millennials and applied the Unified Theory of Acceptance and Use of Technology (UTAUT) qualitatively to uncover deep insights into their perceptions. Millennials in the research believe that DFT is beneficial for their well-being, but also have concerns regarding social expectations, technology dependence and environmental support. This article firstly contributes towards the psychological sustainability from the perspective of digital well-being in tourism. Second, the qualitative use of UTAUT in a technology disconnection setting is novel. Finally, the study contributes to the empirical understanding of DFT from the aspect of millennials’ perceptions. The study proposes that mental “away” should be aligned with physical “away” by reducing technology use to achieve psychological sustainability on holiday

    Single Gene Deletions of Orexin, Leptin, Neuropeptide Y, and Ghrelin Do Not Appreciably Alter Food Anticipatory Activity in Mice

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    Timing activity to match resource availability is a widely conserved ability in nature. Scheduled feeding of a limited amount of food induces increased activity prior to feeding time in animals as diverse as fish and rodents. Typically, food anticipatory activity (FAA) involves temporally restricting unlimited food access (RF) to several hours in the middle of the light cycle, which is a time of day when rodents are not normally active. We compared this model to calorie restriction (CR), giving the mice 60% of their normal daily calorie intake at the same time each day. Measurement of body temperature and home cage behaviors suggests that the RF and CR models are very similar but CR has the advantage of a clearly defined food intake and more stable mean body temperature. Using the CR model, we then attempted to verify the published result that orexin deletion diminishes food anticipatory activity (FAA) but observed little to no diminution in the response to CR and, surprisingly, that orexin KO mice are refractory to body weight loss on a CR diet. Next we tested the orexigenic neuropeptide Y (NPY) and ghrelin and the anorexigenic hormone, leptin, using mouse mutants. NPY deletion did not alter the behavior or physiological response to CR. Leptin deletion impaired FAA in terms of some activity measures, such as walking and rearing, but did not substantially diminish hanging behavior preceding feeding time, suggesting that leptin knockout mice do anticipate daily meal time but do not manifest the full spectrum of activities that typify FAA. Ghrelin knockout mice do not have impaired FAA on a CR diet. Collectively, these results suggest that the individual hormones and neuropepetides tested do not regulate FAA by acting individually but this does not rule out the possibility of their concerted action in mediating FAA

    Consumer behaviour in tourism: Concepts, influences and opportunities

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    Although consumer behaviour (CB) is one of the most researched areas in the field of tourism, few extensive reviews of the body of knowledge in this area exist. This review article examines what we argue are the key concepts, external influences and opportune research contexts in contemporary tourism CB research. Using a narrative review, we examine the CB literature published in three major tourism journals from 2000 to 2012. Of 519 articles identified and reviewed, 191 are included in this article. We examine the development of and scope for future research on nine key concepts, including decision-making, values, motivations, self-concept and personality, expectations, attitudes, perceptions, satisfaction, trust and loyalty. We then examine three important external influences on tourism behaviour, technology, Generation Y and the rise in concern over ethical consumption. Finally, we identify and discuss five research contexts that represent major areas for future scholarship: group and joint decision-making, under-researched segments, cross-cultural issues in emerging markets, emotions and consumer misbehaviour. Our examination of key research gaps is concluded by arguing that the hedonic and affective aspects of CB research in tourism must be brought to bear on the wider CB and marketing literature

    Distinct Functions of Period2 and Period3 in the Mouse Circadian System Revealed by In Vitro Analysis

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    The mammalian circadian system, which is composed of a master pacemaker in the suprachiasmatic nuclei (SCN) as well as other oscillators in the brain and peripheral tissues, controls daily rhythms of behavior and physiology. Lesions of the SCN abolish circadian rhythms of locomotor activity and transplants of fetal SCN tissue restore rhythmic behavior with the periodicity of the donor's genotype, suggesting that the SCN determines the period of the circadian behavioral rhythm. According to the model of timekeeping in the SCN, the Period (Per) genes are important elements of the transcriptional/translational feedback loops that generate the endogenous circadian rhythm. Previous studies have investigated the functions of the Per genes by examining locomotor activity in mice lacking functional PERIOD proteins. Variable behavioral phenotypes were observed depending on the line and genetic background of the mice. In the current study we assessed both wheel-running activity and Per1-promoter-driven luciferase expression (Per1-luc) in cultured SCN, pituitary, and lung explants from Per2−/− and Per3−/− mice congenic with the C57BL/6J strain. We found that the Per2−/− phenotype is enhanced in vitro compared to in vivo, such that the period of Per1-luc expression in Per2−/− SCN explants is 1.5 hours shorter than in Per2+/+ SCN, while the free-running period of wheel-running activity is only 11 minutes shorter in Per2−/− compared to Per2+/+ mice. In contrast, circadian rhythms in SCN explants from Per3−/− mice do not differ from Per3+/+ mice. Instead, the period and phase of Per1-luc expression are significantly altered in Per3−/− pituitary and lung explants compared to Per3+/+ mice. Taken together these data suggest that the function of each Per gene may differ between tissues. Per2 appears to be important for period determination in the SCN, while Per3 participates in timekeeping in the pituitary and lung
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