446 research outputs found

    Sustainable Tourism Marketing Strategies at UNESCO World Heritage Sites

    Full text link
    Designation as a United Nations Educational Scientific and Cultural Organization (UNESCO) World Heritage site has a significant impact on the tourism development and sustainability of a site, city, region or country. World Heritage sites bring a certain level of prestige and international recognition, but they also have an impact on the local communities as they impact day to day life and rituals of the residents. Several paradigms exist in evaluating the success of a UNESCO World Heritage site. This paper specifically examines how marketing strategies bolster sustainable tourism efforts

    Numerical investigation of droplet evaporation modeling in combustion environment

    Get PDF
    Two of the most employed droplet evaporation models in CFD (Computational Fluid Dynamics) applications are analyzed in a numerical context. Both are the infinite liquid conductivity versions of Abramzon-Sirignano and Miller et al. models. The study comprehends a systematic investigation of both models and different procedures used to address thermo-chemical properties. Initially, investigations are addressed in a single droplet framework for different fuels (i.e. ethanol, hexane, and decane). Herein, available experimental data give support to the corresponding discussions. In a second part, the two models and the simplification of the surrounding gas mixture by air are investigated in flames propagating in ethanol droplet mists. A detailed chemistry model is used to represent the combustion of ethanol in air. Results help the choice of methods employed for droplet evaporation modeling in a general context. The methodology adopted in our analyses allows the assessment of each simplification and converges to an optimal combination of methods.</p

    Early embryonic requirement for nucleoporin Nup35/NPP-19 in nuclear assembly

    Get PDF
    11 pages, 8 figures, 3 tables.-- PMID: 19146848 [PubMed].-- Available online Dec 30, 2008.Supporting information (Suppl. figs S1-S5, movies S1-S6) available at: http://dx.doi.org/10.1016/j.ydbio.2008.12.024Nuclear pore complexes (NPCs) are gateways for transport between the nucleus and cytoplasm of eukaryotic cells and play crucial roles in regulation of gene expression. NPCs are composed of multiple copies of not, vert, similar 30 different nucleoporins (nups) that display both ubiquitous and cell type specific functions during development. Vertebrate Nup35 (also known as Nup53) was previously described to interact with Nup93, Nup155 and Nup205 and to be required for nuclear envelope (NE) assembly in vitro. Here, we report the first in vivo characterization of a Nup35 mutation, npp-19(tm2886), and its temperature-dependent effects on Caenorhabditis elegans embryogenesis. At restrictive temperature, npp-19(tm2886) embryos exhibit chromosome missegregation, nuclear morphology defects and die around mid-gastrulation. Depletion of Nup35/NPP-19 inhibits NE localization of Nup155/NPP-8, NPC assembly and nuclear lamina formation. Consequently, nuclear envelope function, including nucleo-cytoplasmic transport, is impaired. In contrast, recruitment of Nup107/NPP-5, LEM-2 and nuclear membranes to the chromatin surface is Nup35/NPP-19-independent, suggesting an uncoupling of nuclear membrane targeting and NPC assembly in the absence of Nup35/NPP-19. We propose that Nup35/NPP-19 has an evolutionary conserved role in NE formation and function, and that this role is particularly critical during the rapid cell divisions of early embryogenesis.This work was funded by grants from the Spanish Ministry of Science and Education (RYC-2003-001521, BFU-2004-01096, BFU-2007-60116) to PA. In addition, we wish to acknowledge Fundación Ramón Areces for a fellowship to ER and Junta de Andalucía for institutional support.Peer reviewe

    Dynamic Behavior of a Sensible-heat based Thermal Energy Storage

    Get PDF
    AbstractIn this paper, a mathematical model is developed to study the behavior of thermal energy storage (TES) under operation in the particular case of Adiabatic Compressed Air Energy Storage (A CAES). The A CAES consists of storing the available extra electrical energy of the electricity network in a form of compressed air (in a cavern) to discharge it during peak periods. The TES sub-system is used to charge and discharge the corresponding heat of compression, leading to a quasi adiabatic mode and an increase in the overall electricity storage efficiency (roughly from 50 to 70%) compared to diabatic CAES. The mathematical model has been converted into a computer simulation program with all the effective parameters of heat transfer in the storage reservoir. This model used to define a geometry reservoir able of storing a given power and restore it while maintaining a required temperature level at the output of unit. The influence of the input and output parameters on the storage efficiency is studied. The results illustrate the behavior of the storage reservoir under dynamic mode

    Seed systems and crop genetic diversity in agroecosystems

    Get PDF
    Poster presented at the First Diversitas Open Science Conference. Oaxaca (Mexico), 9-12 Nov 200

    Influence of Growth Stage and Leaf Age on Expression of the Components of Partial Resistance of Faba Bean to Botrytis fabae Sard.

    Get PDF
    In detached leaf tests on faba bean (Vicia faba L.), genotypes partially resistant and susceptible to Botrytis fabae were examined. Expression of four components of partial resistance to a virulent isolate of B. fabae differed depending on the plant age and the leaf age of the genotypes. The incubation period of resistant genotypes at the podding stage was longer than that of susceptible genotypes at the same stage. The area under disease progress curve (AUDPC) of the lesion size increased from the seedling to the flowering stage but declined at the podding stage in all genotypes. Differences between resistant and susceptible genotypes for lesion size were significant except on old leaves from plants at the podding stage. The latent period decreased, and spore production increased with increasing growth and leaf age but there was significant interaction with the genotype. These last two components of partial resistance were more clearly expressed at all growth stages on FRY167 (highly resistant) but were expressed only at the seedling and podding stages on FRY7 (resistant). The resistant line BPL710 was not significantly different from the susceptible genotypes for the latent period at any growth stage, and for spore production at the seedling and flowering stages. Leaf age affected all genotypes, but with a significant interaction between leaf age and growth stage. Components of partial resistance were more strongly expressed on young leaves from plants at the seedling or flowering stage

    Mind the Gap I: Hα\alpha Activity of M Dwarfs Near the Partially/Fully Convective Boundary and a New Hα\alpha Emission Deficiency Zone on the Main Sequence

    Full text link
    Since identifying the gap in the H-R Diagram (HRD) marking the transition between partially and fully convective interiors, a unique type of slowly pulsating M dwarf has been proposed. These unstable M dwarfs provide new laboratories in which to understand how changing interior structures result in potentially observable activity at the surface. In this work, we report the results of the largest high-resolution spectroscopic Hα\alpha emission survey to date spanning this transition region, including 480 M dwarfs observed using the CHIRON spectrograph at CTIO/SMARTS 1.5-m. We find that M dwarfs with Hα\alpha in emission are almost entirely found 0 to 0.5 magnitude above the top edge of the gap in the HRD, whereas effectively no stars in and below the gap show emission. Thus, the top edge of the gap marks a relatively sharp activity transition and there is no anomalous Hα\alpha activity for stars in the gap. We also identify a new region at 10.3 <MG<<M_{G}< 10.8 on the main sequence where fewer M dwarfs exhibit Hα\alpha emission compared to M dwarfs above and below this magnitude range. Careful evaluation of literature results indicates that 1) rotation and Hα\alpha activity distributions on the main sequence are closely related, and 2) fewer stars in this absolute magnitude range rotate in less than \sim13 days than populations surrounding this region. This result suggests that the most massive fully convective stars lose their angular momentum faster than both partially convective stars and less massive fully convective stars.Comment: 30 pages, 18 figures, and 6 table. Submitted to A

    Towards an optimization of turbulence effects on heat and mass transfer in evaporating and reacting gas turbine sprays

    Get PDF
    ABSTRACT In this paper, the way towards an optimization of turbulence effects on heat and mass transfer in evaporating and reacting GT-sprays is outlined. It is based on an accurate consideration of coupling between turbulence and turbulence modulation, swirl intensity and non-equilibrium effects during the vaporization. This is achieved by including a physically consistent modelling of turbulence modulation phenomena that allows to better retrieve mass and heat transport effects on the droplet surface, and therefore improves the prediction of processes, like evaporation and combustion, which in turn affect the turbulence. For this purpose, an Euler-Lagrangian method in conjunction with advanced models has been used in RANScontext and applied to the numerical study of a single gas turbine combustor configuration. a) To quantify, to control or to optimize the effects of turbulence along with the swirl intensity effects, a mixing parameter has been introduced. b) Under reacting conditions, it is shown how the evaporation characteristics, mixing rate and combustion process are influenced by turbulence. In particular, the turbulence modulation modifies the evaporation rate, which in turn influences the mixing and the species concentration distribution. It is demonstrated that this effect can not be neglected far from the nozzle for low swirl intensities (Sw.Nu.&lt;1) and close to the nozzle for high swirl number intensities. All these findings can well be used to optimize turbulence effects in evaporating and reacting sprays. INTRODUCTION The success of some promising approaches, such as the LPP-or the RQL-concept strategies, that can help to limit gas turbine emissions, depends on a suitable homogeneity of the air-fuel mixture in the reaction zone. To achieve this goal by means of numerical simulations, an accurate determination of droplet and vapour spatial distribution and a reliable control of the interaction between the evaporating and reacting spray with the surrounding turbulent gas flow are prerequisite. As pointed out in [1, 2] a considerable amount of works have been done including diverse parameter studies (e. g. [1-5, 8-15, 20-25, 34]. However, there are relatively few experimental and numerical results devoted to the effects of turbulence characteristics on spray combustio
    corecore