75 research outputs found

    Tourism discretionary spending choice behaviour

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    Studies of tourism demand are numerous. But studies of how consumers apportion discretionary resources to tourism and across other competing categories of discretionary expenditure are non-existent. Therefore, how individuals and households make trade-offs between, or assess the respective utilities of, the various categories of discretionary expenditure and allocate discretionary financial resources, appears to be unknown. This study seeks to address this need by examining discretionary expenditure through choice experiments. The data provide insights into how each type of discretionary expenditure is valued and how each type competes for a share of the discretionary expenditure ‘pie’. We discuss the results with an emphasis on the implications for tourism marketing

    New horses for old courses - questioning the limitations of sustainable tourism to supply-driven measures and the nature-based context

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    It seems a general belief that (1) sustainable tourism is supply-driven, and (2) sustainable tourists are visitors engaging in nature-based travel activities. Results reported in this paper challenge these assumptions. Findings from an online survey indicate that nature-based travel is not solely related to environmentally protective attitudes. Market-driven mechanisms could therefore be used to strengthen ecological sustainable tourism. Only 39 % of respondents classified as ‘Ecologically Caring Tourists’ stated that an intense experience of nature is a motivation for their vacation travel behaviour. The findings indicate two possible directions for the strengthening of sustainable tourism measures: (1) demand-driven mechanisms could be used in addition to supply-side measures to identify and attract groups of tourists with a smaller ecological footprint; (2) the tourism market suitable to increase ecological sustainability is likely to be much larger than assumed by focusing on nature-based tourism only. These findings could be of great benefit to any tourism destination in terms of the development of new tools and the identification of new tourism contexts for managing ecological sustainability

    Modified Needle-Tip PcrV Proteins Reveal Distinct Phenotypes Relevant to the Control of Type III Secretion and Intoxication by Pseudomonas aeruginosa

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    The type III secretion system (T3SS) is employed to deliver effector proteins to the cytosol of eukaryotic hosts by multiple species of Gram-negative bacteria, including Pseudomonas aeruginosa. Translocation of effectors is dependent on the proteins encoded by the pcrGVHpopBD operon. These proteins form a T3S translocator complex, composed of a needle-tip complex (PcrV), translocons (PopB and PopD), and chaperones (PcrG and PcrH). PcrV mediates the folding and insertion of PopB/PopD in host plasmic membranes, where assembled translocons form a translocation channel. Assembly of this complex and delivery of effectors through this machinery is tightly controlled by PcrV, yet the multifunctional aspects of this molecule have not been defined. In addition, PcrV is a protective antigen for P. aeruginosa infection as is the ortholog, LcrV, for Yersinia. We constructed PcrV derivatives containing in-frame linker insertions and site-specific mutations. The expression of these derivatives was regulated by a T3S-specific promoter in a pcrV-null mutant of PA103. Nine derivatives disrupted the regulation of effector secretion and constitutively released an effector protein into growth medium. Three of these regulatory mutants, in which the linker was inserted in the N-terminal globular domain, were competent for the translocation of a cytotoxin, ExoU, into eukaryotic host cells. We also isolated strains expressing a delayed-toxicity phenotype, which secrete translocators slowly despite the normal level of effector secretion. Most of the cytotoxic translocation-competent strains retained the protective epitope of PcrV derivatives, and Mab166 was able to protect erythrocytes during infection with these strains. The use of defined PcrV derivatives possessing distinct phenotypes may lead to a better understanding of the functional aspects of T3 needle-tip proteins and the development of therapeutic agents or vaccines targeting T3SS-mediated intoxication

    Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

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    The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

    Agricultural uses of plant biostimulants

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