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51.
Abraham J Abreu P Aglietta M Aguirre C Allard D Allekotte I Allen J Allison P Alvarez-Muñiz J Ambrosio M Anchordoqui L Andringa S Anzalone A Aramo C Argirò S Arisaka K Armengaud E Arneodo F Arqueros F Asch T Asorey H Assis P Atulugama BS Aublin J Ave M Avila G Bäcker T Badagnani D Barbosa AF Barnhill D Barroso SL Baughman B Bauleo P Beatty JJ Beau T Becker BR Becker KH Bellido JA Benzvi S Berat C Bergmann T Bernardini P Bertou X Biermann PL Billoir P Blanch-Bigas O Blanco F Blasi P Bleve C 《Physical review letters》2008,101(6):061101
The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min. 相似文献
52.
Ohne Zusammenfassung 相似文献
53.
Oliveira E Amara I Bellido D Odena MA Domínguez E Pagès M Goday A 《Journal of mass spectrometry : JMS》2007,42(11):1485-1495
Protein identification in systems containing very highly abundant proteins is not always efficient and usually requires previous enrichment or fractionation steps in order to uncover minor proteins. In plant seeds, identification of late embryogenesis abundant (LEA) proteins is often masked by the presence of the large family of storage proteins. LEA-proteins are predicted to play a role in plant stress tolerance. They are highly hydrophilic proteins, generally heat-stable, and correlate with dehydration in seeds or vegetative tissues. In the present work, we analyze the protein composition of heat-stable Arabidopsis thaliana seed extracts after treatment with trichloroacetic acid (TCA). The composition of the proteins that precipitate and those that remain in solution in 3% TCA was analyzed by two different approaches: 1D SDS-PAGE coupled to LC-ESI-MSMS analysis and a gel-free protocol associated with LC-MALDI-MSMS. Our results indicate that treating total heat-soluble extracts with 3% TCA is an effective procedure to remove storage proteins by selective precipitation and this fractionation step provides a soluble fraction highly enriched in Lea-type proteins. The analysis and determination of protein identities in this acid-soluble fraction by MS technology is a suitable system for large-scale identification of Lea-proteins present in seeds. 相似文献
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We consider an optimal design problem in wave propagation proposed in Sigmund and Jensen (Roy. Soc. Lond. Philos. Trans. Ser. A 361:1001–1019, 2003) in the one-dimensional situation: Given two materials at our disposal with different elastic Young modulus and different density, the problem consists of finding the best distributions of the two initial materials in a rod in order to minimize the vibration energy in the structure under periodic loading of driving frequency Ω. We comment on relaxation and optimality conditions, and perform numerical simulations of the optimal configurations. We prove also the existence of classical solutions in certain cases. 相似文献
57.
Ernesto Aranda Jose Carlos Bellido Alberto Donoso 《Journal of Optimization Theory and Applications》2012,154(2):443-461
In this paper, we devise a computational method for simulating optimal elastic materials made of two phases that maximize torsional stiffness under local stress constraints. Our method relies on a theoretical relaxation result and it is capable to find optimal layouts involving microstructure among the constituents. 相似文献
58.
D. R. Araripe L. F. Bellido S. R. Patchineelam A. V. B. Bellido M. T. Guimar?es M. B. A. Vasconcellos 《Journal of Radioanalytical and Nuclear Chemistry》2006,270(1):103-109
Summary The goal of the present work was to determine the concentration of 23 elements by instrumental neutron activation analysis
in rock samples from the vicinity of Itingussú River, in order to investigate the contribution of trace and major elements
from the local lithology to the river basin. The Itingussú River Basin ends in a mangrove area not yet largely impacted by
antropogenic activities. So far, there are no data for the concentration of trace elements in that region, even though these
data are important to the understanding of the influence of the rocks on the composition of the mangrove sediments. The results
showed some enrichment of Th and some light rare earths, probably because of the presence of the mineral allanite and other
accessory minerals, as identified by petrographic analysis. 相似文献
59.
This paper obtains solitons as well as other solutions to a few nonlinear evolution equations that appear in various areas of mathematical physics. The two analytical integrators that are applied to extract solutions are tan–cot method and functional variable approaches. The soliton solutions can be used in the further study of shallow water waves in (1+1) as well as (2+1) dimensions. 相似文献
60.
F. Guillén–González M. A. Rodríguez–Bellido M. A. Rojas–Medar 《Mathematische Nachrichten》2009,282(6):846-867
In [3], L. Berselli showed that the regularity criterion ? u ∈ (0, T; L q (Ω)), for some q ∈ (3/2, + ∞], implies regularity for the weak solutions of the Navier–Stokes equations, being u the velocity field. In this work, we prove that such hypothesis on the velocity gradient is also sufficient to obtain regularity for a nematic Liquid Crystal model (a coupled system of velocity u and orientation crystals vector d ) when periodic boundary conditions for d are considered (without regularity hypothesis on d ). For Neumann and Dirichlet cases, the same result holds only for q ∈ [2, 3], whereas for q ∈ (3/2, 2) ∪ (3, + ∞] additional regularity hypothesis for d (either on ? d or Δ d ) must be imposed. On the other hand, when the Serrin's criterion u ∈ (0, T; L p (Ω)) with some p ∈ (3, + ∞] ([16]) for u is imposed, we can obtain regularity of the system only in the problem of periodic boundary conditions for d . When Neumann and Dirichlet cases for d are considered, additional regularity for d must be imposed for each p ∈ (3, + ∞] (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献