The effect of sport tourists' travel style, destination and event choices, and motivation on their involvement in small-scale sports events

This exploratory study investigates whether and in which way motivation and destination, travel and event selection criteria influence sport tourists ’ involvement in small-scale events. Thus, a model was developed and tested at a small scale sport event in Sfendami, Greece. To test the six hypotheses of the proposed model a primary research study was conducted, which received responses from 181 participants. Implementation of the partial least square technique showed that changes in sport tourists’ travel style exert a direct and positive effect on involvement, as well as an indirect effect with motivation acting as a mediator; however, perception of destination and events characteristics does not exert a significant influence on participants’ involvement. Additionally, the model's ability to predict the motivational aspects of sport tourists’ participation was demonstrated. Multidimensional scaling was employed to assist with event service design and improve organizers’ capabilities to develop effective promotional strategies

Investigation of intracellular signals generated by γ-interferon and IL-4 leading to the induction of class II antigen expression

Signal transduction plays a vital role in cellular behaviour as cells respond to various stimuli in different ways and utilize diverse pathways for accomplishing their task. Determination of the pathway followed by various cytokines can be achieved using specific inhibitors which include theophylline (TPH), TMB-8 and W7 that hinder calmodulin binding to Ca2+; sphingosine (SPH), H7 and staurosporine that inhibit protein kinase C (PKC) activation; and mevalonate (MEV) or the anti-p21ras antibody which block G-proteins. This study shows that the immunologically important class II antigens in human cells are up-regulated predominately via the same pathway after gamma-interferon (γ-IFN) treatment, whereas murine cells are activated by other signalling routes. Thus, the calcium/calmodulin (Ca2+/Cam) pathway is preferentially selected for human cells whereas the PKC pathway is more often chosen for murine cells. These findings are firmly supported by other reports and show, in addition, a unique action exerted by γ-IFN, since IL-4, another inducer of class II antigen expression, uses different pathways. This diversity of activation reveals the existence of a previously unknown complicated network of intracellular interactions able to regulate the same phenotype or cellular event. As major histocompatibility complex antigens (MHC) or human leukocyte antigens (HLA), are important in immune recognition and response, the results show that for human cells a more coherent method of HLA-DR antigen induction is followed after γ-IFN administration, as calcium participation seems to be the first step in signal transduction. The same T-cell derived lymphokine, however, follows a totally different route when applied to murine cells

Bioprocess modelling of biohydrogen production by Rhodopseudomonas palustris: Model development and effects of operating conditions on hydrogen yield and glycerol conversion efficiency

This research explores the photofermentation of glycerol to hydrogen by Rhodopseudomonas palus- tris, with the objective to maximise hydrogen production. Two piecewise models are designed to simulate the entire growth phase of R. palustris; a challenge that few dynamic models can accomplish. The parameters in both models were fitted by the present batch experiments through the solution of the underlying optimal control problems by means of stable and accurate discretisation techniques. It was found that an initial glutamate to glycerol ratio of 0.25 was optimal, and was independent of the initial biomass concentration. The glycerol conversion efficiency was found to depend on initial biomass concentration and its computational peak is 64.4%. By optimising a 30-day industrially relevant batch process, the hydrogen productivity was improved to be 37.7 mL·g biomass-1·hr-1 and the glycerol conversion efficiency was maintained at 58%. The models can then be applied as the connection to transfer biohydrogen production from laboratory scale into industrial scale.Authors N. Xiao and Dr. K. T. Mahbubani are funded through the KACST-Cambridge Center for Advanced Material Manufacture, the author E. A. del Rio-Chanona is found by CONACyT scholarship No. 522530 from the Secretariat of Public Education and the Mexican government.This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0009250915001815

Scaling of solar wind e and the AU, AL and AE indices as seen by WIND

We apply the finite size scaling technique to quantify the statistical properties of fluctuations in AU, AL and AE indices and in the parameter that represents energy input from the solar wind into the magnetosphere. We find that the exponents needed to rescale the probability density functions (PDF) of the fluctuations are the same to within experimental error for all four quantities. This self-similarity persists for time scales up to ~4 hours for AU, AL and and up to ~2 hours for AE. Fluctuations on shorter time scales than these are found to have similar long-tailed (leptokurtic) PDF, consistent with an underlying turbulent process. These quantitative and model-independent results place important constraints on models for the coupled solar wind-magnetosphere system

The diffusion-induced nova scenario. CK Vul and PB 8 as possible observational counterparts

We propose a scenario for the formation of DA white dwarfs with very thin helium buffers. For these stars we explore the possible occurrence of diffusion-induced CNO- flashes, during their early cooling stage. In order to obtain very thin helium buffers, we simulate the formation of low mass remnants through an AGB final/late thermal pulse (AFTP/LTP scenario). Then we calculate the consequent white dwarf cooling evolution by means of a consistent treatment of element diffusion and nuclear burning. Based on physically sounding white dwarf models, we find that the range of helium buffer masses for these diffusion-induced novas to occur is significantly smaller than that predicted by the only previous study of this scenario. As a matter of fact, we find that these flashes do occur only in some low-mass (M < 0.6M) and low metallicity (Z_ZAMS <0.001) remnants about 10^6 - 10^7 yr after departing from the AGB. For these objects, we expect the luminosity to increase by about 4 orders of magnitude in less than a decade. We also show that diffusion-induced novas should display a very typical eruption lightcurve, with an increase of about a few magnitudes per year before reaching a maximum of M_V ~ -5 to -6. Our simulations show that surface abundances after the outburst are characterized by logNH/NHe ~ -0.15...0.6 and N>C>O by mass fractions. Contrary to previous speculations we show that these events are not recurrent and do not change substantially the final H-content of the cool (DA) white dwarf. (Abridged)Comment: 16 pages, 8 figures, 3 tables. Replaced to match the final version published by MNRAS. The definitive version is available at http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-296

Eruptions of the V838 Mon type: stellar merger versus nuclear outburst models

We discuss various models and scenarios proposed to explain the nature of the V838 Mon type eruptions. In this class of eruptive objects we include: M31 RV (erupted in 1988), V4332 Sgr (erupted in 1994) and V838 Mon (erupted in 2002). We concentrate on three models: (i) thermonuclear runaway on an accreting white dwarf (nova-like event); (ii) He-shell flash in a post asymptotic giant branch star (born-again AGB); and (iii) merger of stars. We show that models (i) and (ii) cannot account for the majority of the observed properties of the objects. Most significantly, in both nuclear burning type models the object is expected to heat up before declining and fade as a very hot compact star. In the observed eruptions the objects declined as very cool giants or supergiants. We show that the stellar merger model can account for all the observed properties and conclude that presently this is the most promising model to explain the eruptions of the V838 Mon type.Comment: 15 pages, 1 figure, accepted in A&

Simulation-To-Flight (STF-1): A Mission to Enable CubeSat Software-Based Validation and Verification

The Simulation-to-Flight 1 (STF-1) CubeSat mission aims to demonstrate how legacy simulation technologies may be adapted for flexible and effective use on missions using the CubeSat platform. These technologies, named NASA Operational Simulator (NOS), have demonstrated significant value on several missions such as James Webb Space Telescope, Global Precipitation Measurement, Juno, and Deep Space Climate Observatory in the areas of software development, mission operations/training, verification and validation (V&V), test procedure development and software systems check-out. STF-1 will demonstrate a highly portable simulation and test platform that allows seamless transition of mission development artifacts to flight products. This environment will decrease development time of future CubeSat missions by lessening the dependency on hardware resources. In addition, through a partnership between NASA GSFC, the West Virginia Space Grant Consortium and West Virginia University, the STF-1 CubeSat will hosts payloads for three secondary objectives that aim to advance engineering and physical-science research in the areas of navigation systems of small satellites, provide useful data for understanding magnetosphere-ionosphere coupling and space weather, and verify the performance and durability of III-V Nitride-based materials