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81.
Abbasi RU Abu-Zayyad T Allen M Amman JF Archbold G Belov K Belz JW Ben Zvi SY Bergman DR Blake SA Brusova OA Burt GW Cannon C Cao Z Connolly BC Deng W Fedorova Y Finley CB Gray RC Hanlon WF Hoffman CM Holzscheiter MH Hughes G Hüntemeyer P Jones BF Jui CC Kim K Kirn MA Loh EC Maestas MM Manago N Marek LJ Martens K Matthews JA Matthews JN Moore SA O'Neill A Painter CA Perera L Reil K Riehle R Roberts M Rodriguez D Sasaki N Schnetzer SR Scott LM Sinnis G Smith JD Sokolsky P Song C Springer RW 《Physical review letters》2008,100(10):101101
The High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10(19) eV, consistent with the expected cutoff energy. We observe the ankle of the cosmic-ray energy spectrum as well, at an energy of 4 x 10(18) eV. We describe the experiment, data collection, and analysis and estimate the systematic uncertainties. The results are presented and the calculation of the statistical significance of our observation is described. 相似文献
82.
83.
This paper is concerned with the part that the design of the highway and the management of the traffic on it can play in noise problems. The noise characteristics of individual vehicles and of traffic are summarized in the Appendixes. Attention is confined to vehicles with conventional petrol and diesel engines and to noise outside the vehicles. Alternative methods of reducing traffic noise are compared and their effects on other aspects of the highway and the traffic are considered. The conclusion is drawn that there are two alternative approaches to noise reduction. One is to reduce traffic flow and the other is to make use of noise barriers and environmental design. The relative importance of these two approaches depends on the type of road under consideration. 相似文献
84.
M Bárány K Bárány C T Burt T Glonek T C Myers 《Journal of supramolecular structure》1975,3(2):125-140
The reactivity of myosin to [14C]-labeled N-ethylmaleimide ([14C]NEM) or to tritium was determined in functionally different frog muscles. The incorporation of [14C]NEM into myosin decreased during isotonic or isometric contractions, as compared to resting muscle. The cysteine residues which were protected during contraction were not involved in the ATPase activity or the actin-binding ability of myosin. Peptide mapping revealed that several residues were protected simultaneously. The incorporation of tritium into the peptide N-H groups of myosin was also decreased during muscle activity. These data support the idea that activation and subsequent contraction of muscle are correlated with structural changes in the myosin molecule. The reactivity of myosin to [14C]NEM was increased when the muscle was stretched to 140% rest length and treated with iodoacetate to deplete ATP. Based on in vitro experiments and on literature data, it is suggested that in the resting muscle myosin contains bound MgATP which decreases the rate of incorporation of [14C]NEM into myosin and that upon the irreversible loss of ATP the rate increases. 31P nuclear magnetic resonance signals from a number of phosphates were detected in the intact frog muscle. The data indicated that the minimum concentration of ATP in the muscle is 3 mM, a value which agrees with that of chemical determination. The characteristic chemical shifts, coupling constants, and line widths of ATP in the muscle were considerably altered from that of either free ATP in aqueous solutions or ATP in perchloric acid extracts of muscle. 相似文献
85.
A novel strategy for the synthesis of oligosaccharides, involving the use of a solid phase peptide template, has been successfully applied to the construction of a twelve member disaccharide library. 相似文献
86.
[structure: see text] A novel (two-zone process with different spin-state channels) mechanistic picture for the Jacobsen-Katsuki reaction is presented that provides insight into the still elusive understanding of the epoxidation mechanism. For the first time, we show that the salen moiety of the catalyst can be explicitly involved in the epoxidation process. 相似文献
87.
Philip B. Burt 《Journal of Mathematical Analysis and Applications》1980,73(1):49-51
Exact solutions of nonlinear generalizations of the wave equation are constructed. In some cases these solutions are solitary waves or solitions. Thus, by explicit construction solitons or solitary waves are shown to exist in dispersionless systems. In contrast to previous solitary wave solutions, these solutions are limiting cases of solutions of nonlinear partial differential equations with dispersion. 相似文献
88.
We present a mechanism for fermion mass generation, and apply it to the lepton sector of the Weinberg-Salam model. Extra fields, necessary to produce the large mass splittings of the observed fermions, form bound states more massive than the electroweak scale. 相似文献
89.
It is shown how to construct effective lagrangians to the two-loop level for non-abelian gauge theories, quantized in background field gauge. This construction is no more difficult than the analogous computation in abelian gauge theories when minimal subtraction is employed. It is argued that for three or more loops, one can no longer separate heavy or mixed light-heavy graphs in an intermediate renormalization, and the more general algorithm presented by us in an earlier work must be employed even in background field gauge. 相似文献
90.