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61.
In this paper we show how to establish a reliable and efficient high level communication system in a randomly deployed network of sensors equipped with directional antennas. This high level communication system enables the programming of the sensor network using high level communication functionalities without the burden of taking care of their physical capacities (low range, unidirectional links, single frequency, presence of collisions, etc.). The high level communication functionalities we offer include point-to-point communication, point-to-area communication, and one-to-all communication. The basic idea to implement this system is to simulate a virtual network that emerges from the ad-hoc network using self-organization, self-discovery and collaborative methods. We also analyse the efficiency, scalability and robustness of the proposed protocols. 相似文献
62.
Marcos Hernández Suárez Jordi Rull Pallarés Domingo Ríos Mesa Elena Rodríguez Rodríguez Carlos Díaz Romero 《Journal of the science of food and agriculture》2008,88(11):1882-1891
BACKGROUND: Tomato producers are looking for alternatives to protect their crops against the tomato yellow leaf curl virus (TYLCV), including replacement of cultivars with other more resistant ones. Major chemical components, sugars, mineral composition, organic acids, lycopene, total phenols and hydroxycinnamic acids were determined in six tomato cultivars, three of them (Boludo, Dorothy and Tyna) resistant, and the other three (Daniela, Dominique and Thomas), non‐resistant against TYLCV. RESULTS: The Daniela cultivar showed the greatest difference with respect to the others, mostly due to the higher content of soluble solids. The major significant differences between the mean values according to the cultivar and resistance against the TYLCV were observed for total soluble solids, pH, ascorbic acid, total phenols and hydroxycinnamic acids. High coefficients of correlation were found between glucose and fructose, and among ferulic, caffeic and p‐coumaric acids. CONCLUSION: Linear discriminant analysis made it possible to differentiate tomato samples according to the cultivar. A clear varietal influence on the chemical composition was observed; however, resistance or non‐resistance against TYLCV does not seem to influence the chemical composition. Copyright © 2008 Society of Chemical Industry 相似文献
63.
Originally, Wireless Local Area Networks served only small indoor areas. Nevertheless, the idea of employing IEEE 802.11 networks in large outdoor environments is
a very attractive possibility. IEEE 802.11 technology offers several advantages: the low cost of equipment, its operation
in the unlicensed spectrum and its higher data rates. Since the advent of the first IEEE 802.11 standard, a great deal of
research has been carried out. So-called Wifi-based Long Distance networks are currently being deployed. In this paper, we study the suitability of employing IEEE 802.11 networks in large
outdoor environments without modifying the standard working procedure. In such scenarios, IEEE 802.11 networks should offer
coverage ranges of several kilometer, which leads to high propagation delay values. Thus, we analyze the influence of increasing
propagation delay in the IEEE 802.11 MAC protocol. To carry out our analysis we present a mathematical model and simulation
results. We provide an operating range in which IEEE 802.11 performance is feasible and establish a throughput threshold according
to the propagation delay. 相似文献
64.
Víctor Falguera Jordi PagánSalvador Garza Alfonso GarvínAlbert Ibarz 《Food research international (Ottawa, Ont.)》2011,44(6):1580-1588
The effectiveness of ultraviolet irradiation in inactivating microorganisms has been known for decades. Nevertheless, in the processing of foodstuff other important issues must be considered, such as organoleptic or nutritional properties preservation. Ultraviolet irradiation constitutes an alternative to thermal treatment that is being studied and developed to obtain a better final product sensory quality, but without neglecting microbial safety. Moreover, it has been proved that this technology can be useful to decompose some toxins that are not affected by thermal processing. In this piece of work, the effect of UV irradiation on all of these contaminants and components of liquid food has been reviewed. 相似文献
65.
Factors influencing the soil-air partitioning and the strength of soils as a secondary source of polychlorinated biphenyls to the atmosphere 总被引:2,自引:0,他引:2
Cabrerizo A Dachs J Moeckel C Ojeda MJ Caballero G Barceló D Jones KC 《Environmental science & technology》2011,45(11):4785-4792
Soils are a major reservoir of persistent organic pollutants, and soil-air partitioning and exchange are key processes controlling the atmospheric concentrations and regional fate of pollutants. Here, we report and discuss the concentrations of polychlorinated biphenyls (PCBs) in soils, their measured fugacities in soil, the soil-air partition coefficients (K(SA)) and soil-air fugacity gradients in rural background areas of N-NE Spain and N-NW England. Four sampling campaigns were carried out to assess seasonal and daily variability and differences between sampling sites. K(SA) values were significantly dependent on soil temperature and soil organic matter quantity, and to a minor extent organic matter type. All the PCB congeners in the soil are close to equilibrium with the atmosphere at rural Ebro sites, but soil fugacities tend to be higher than ambient air fugacities in early and late summer, consistent with the influence of temperature on soil-air partitioning. Therefore, during warm periods, soils increment their strength as secondary sources to the atmosphere. The mixture of PCBs found in the atmosphere is clearly strongly influenced by the mixture of PCBs which escape from soil, with significant correlations between them (R(2) ranging between 0.35 and 0.74 and p-level <0.001 for the Ebro sampling sites). Conversely, the close-to-equilibrium to net sink status of rural UK sites, suggest a close coupling of air and soil concentrations, but it is not possible to elucidate the importance of these soils as secondary sources yet, and presumably there are still significant primary sources to the regional/global environment. 相似文献
66.
67.
Xavier Ruiz Jordi Pallarés 《International Journal of Heat and Mass Transfer》2012,55(23-24):6966-6978
Three different shear cell arrangements are considered here in order to discuss and compare the accuracy of their measurements at low and moderate Rayleigh number, that is to say, in reduced gravity environments. To do so, specific numerical procedures have been designed in order to quantitatively estimate the corresponding associated errors as a function of time and at the end of the diffusive process. The present work clearly shows that the interdiffusion-couple configuration is, from the point of view of accuracy, the worst one. 相似文献
68.
The Journal of Supercomputing - The high-performance computing (HPC) community has recently started to use containerization to obtain fast, customized, portable, flexible, and reproducible... 相似文献
69.
Nieves Martinez-Peinado Clara Martori Nuria Cortes-Serra Julian Sherman Ana Rodriguez Joaquim Gascon Jordi Alberola Maria-Jesus Pinazo Alheli Rodriguez-Cortes Julio Alonso-Padilla 《International journal of molecular sciences》2021,22(2)
Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects over 6 million people worldwide. Development of new drugs to treat this disease remains a priority since those currently available have variable efficacy and frequent adverse effects, especially during the long regimens required for treating the chronic stage of the disease. T. cruzi modulates the host cell-metabolism to accommodate the cell cytosol into a favorable growth environment and acquire nutrients for its multiplication. In this study we evaluated the specific anti-T. cruzi activity of nine bio-energetic modulator compounds. Notably, we identified that 17-DMAG, which targets the ATP-binding site of heat shock protein 90 (Hsp90), has a very high (sub-micromolar range) selective inhibition of the parasite growth. This inhibitory effect was also highly potent (IC50 = 0.27 μmol L−1) against the amastigote intracellular replicative stage of the parasite. Moreover, molecular docking results suggest that 17-DMAG may bind T. cruzi Hsp90 homologue Hsp83 with good affinity. Evaluation in a mouse model of chronic T. cruzi infection did not show parasite growth inhibition, highlighting the difficulties encountered when going from in vitro assays onto preclinical drug developmental stages. 相似文献
70.
Emerson Luiz dos Santos Veiga Xavier Vendrell Villafruela Jordi Llorca Hector Beltrán-Mir Eloísa Cordoncillo 《Journal of the American Ceramic Society》2023,106(2):1369-1380
One of the alternatives to decrease the concentration of CO is its oxidation reaction to CO2, which can be made more efficient using catalysts. In this work, it is shown that pyrochlore structures are a promising candidate to act as heterogeneous catalysts due to their chemical and physical properties. For use as a catalyst in this reaction, the Pr2Zr2−xFexO7±δ (x = 0, 0.05, 0.10, and 0.15) system was synthesized by the solvothermal method, firing the powder obtained at temperatures of 1200 and 1400°C. The diffraction patterns confirmed the pyrochlore structure as the single phase in all the nominal compositions. The Brunauer–Emmett–Teller method and dynamic light-scattering analysis showed an increase in the particle size and a decrease in the specific surface area when increasing the iron concentration and increasing the calcination temperature. The compositions that presented the best catalytic activity were the samples with the highest iron concentration. Moreover, these samples were able to convert all the CO oxidation reactions in a narrower temperature range than a conventional CeO2 sample. The presence of vacancies and the redox behavior of the elements present are the key factors for the catalysis of this system in the CO oxidation reaction. 相似文献