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81.
Stoeger AS Charlton BD Kratochvil H Fitch WT 《The Journal of the Acoustical Society of America》2011,130(3):1700-1710
Arousal-based physiological changes influence acoustic features of vocalizations in mammals. In particular, nonlinear phenomena are thought to convey information about the caller's arousal state. This hypothesis was tested in the infant African elephant (Loxodonta africana) roar, a call type produced in situations of arousal and distress. Ninety-two percent of roars exhibited nonlinear phenomena, with chaos being the most common type. Acoustic irregularities were strongly associated with elevated fundamental frequency values. Roars produced in situations of highest urgency, based on the occurrence of behavioral indicators of arousal, were characterized by the lowest harmonics-to-noise ratio; this indicates low tonality. In addition, roars produced in these situations lasted longer than those produced in contexts of lower presumed urgency. Testing the infant roars for individual distinctiveness revealed only a moderate classification result. Combined, these findings indicate that infant African elephant roars primarily function to signal the caller's arousal state. The effective communication of this type of information may allow mothers to respond differentially based on their infant's degree of need and may be crucial for the survival of infant African elephants in their natural environment. 相似文献
82.
Parazzoli LP Fitch NJ Zuchowski PS Hutson JM Lewandowski HJ 《Physical review letters》2011,106(19):193201
Controlling interactions between cold molecules using external fields can elucidate the role of quantum mechanics in molecular collisions. We create a new experimental platform in which ultracold rubidium atoms and cold ammonia molecules are separately trapped by magnetic and electric fields and then combined to study collisions. We observe inelastic processes that are faster than expected from earlier field-free calculations. We use quantum scattering calculations to show that electric fields can have a major effect on collision outcomes, even in the absence of dipole-dipole interactions. 相似文献
83.
The surface-active, chain transfer agent (‘transurf’) sodium ω-mercapto-decane sulfonate, SMDSo, was synthesized, purified, and its interfacial properties determined. The compound acted normally in styrene emulsion polymerization to produce extremely stable colloids containing only sulfonate ionic surface functional groups. It was then used to control the surface charge density of a model polystyrene colloid by means of seeded emulsion polymerization. Surface charge could thus be increased 16-fold over that of the seed particles, and was due solely to sulfonate groups introduced by the SMDSo. Unlike most conventional emulsion polymerizations, this technique allows one to control surface chemistry independently of particle size. To cite this article: C.C. Fifield, R.M. Fitch, C. R. Chimie 6 (2003). 相似文献
84.
85.
P. Marage M. Aderholz P. Allport N. Armenise J. P. Baton M. Berggren D. Bertrand V. Brisson F. W. Bullock W. Burkot M. Calicchio E. F. Clayton T. Coghen A. M. Cooper-Sarkar O. Erriquez P. J. Fitch J. Guy F. Hamisi P. O. Hulth G. T. Jones P. Kasper U. F. Katz H. Klein E. Matsinos R. P. Middleton D. B. Miller M. M. Mobayyen D. R. O. Morrison M. Neveu S. W. O'Neale M. A. Parker P. Petiau J. Sacton R. A. Sansum N. Schmitz E. Simopoulou C. Vallée K. Varvell A. Vayaki W. Venus H. Wachsmuth J. Wells W. Wittek BEBC WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1987,35(3):275-282
Coherent production ofρ ? mesons in charged current antineutrino interactions on neon nuclei is studied in the BEBC bubble chamber exposed to the CERN SPS wide band beam. The cross section is measured to be (95±25)·10?40 cm2 per neon nucleus, averaged over the beam energy spectrum. The distributions of kinematical variables and the absolute value of the cross section are in agreement with theoretical predictions based on the CVC hypothesis and the vector meson dominance model. 相似文献
86.
P. J. Tarcha R. M. Fitch J. J. Dumais L. W. Jelinski 《Journal of Polymer Science.Polymer Physics》1983,21(11):2389-2402
Methyl acrylate polymer colloids can be hydrolyzed self-catalytically by bound strong acid surface groups derived from the polymerization initiator. The kinetics of hydrolysis were earlier shown to be apparently pseudo-zeroth-order for any given latex, and first order with respect to surface strong acid concentration. A surface reaction zone model was proposed to explain the kinetics. This model leads to the prediction that the polymer particles will possess a core-shell morphology after some hydrolysis has occurred. This study employs 13C NMR spectroscopy to investigate the particle morphology in the wet latex, a new application for this method. The temperature dependence of the 13C NMR integrated intensities at various levels of hydrolysis provides strong evidence that the particles do possess core-shell morphology, and that the shell is composed of PAA/PMA copolymer. This shell is swollen and plasticized by water, resulting in greatly enhanced segmental mobility of the polymer chains as evidenced by marked narrowing of the NMR lines. Thermal measurements alone cannot distinguish particle morphology because PMA appears to be somewhat compatible with its partially hydrolyzed analog at the temperatures of measurement. 相似文献
87.
P. J. Fitch P. Kasper A. M. Cooper-Sarkar M. Aderholz N. Armenise T. Azemoon D. Bertrand M. Berggren F. W. Bullock M. Calicchio E. F. Clayton T. Coghen O. Erriquez G. Gerbier J. Guy P. O. Hulth G. Iaselli G. T. Jones M. Lagraa P. Marage R. P. Middleton D. Miller M. M. Mobayyen M. Neveu S. W. O'Neale M. A. Parker R. A. Sansum E. Simopoulou K. Varvell C. Vallée A. Vayaki W. Venus H. Wachsmuth W. Wittek J. Wells E. Zevgolatakos BEBC WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1986,31(1):51-58
Evidence for a significant higher twist contribution to highz π? production in antineutrino scattering is presented. In events withW>3 GeV andQ 2>1 GeV2 in our data, it accounts for (51 ±8)% of all π? withz above 0.5. It is consistent with thez?Q 2 correlations of Berger's higher twist prediction. The data are inconclusive concerning the predictedy?z correlation andp T dependence. Thez ?Q 2 correlation is not adequately described by the Lund Monte-Carlo. 相似文献
88.
Huawei Li Hong Liu C Eduardo Corrales Jessica R Risner Jeff Forrester Jeffrey R Holt Stefan Heller Albert SB Edge 《BMC neuroscience》2009,10(1):122
Background
Neural differentiation of embryonic stem (ES) cells is usually achieved by induction of ectoderm in embryoid bodies followed by the enrichment of neuronal progenitors using a variety of factors. Obtaining reproducible percentages of neural cells is difficult and the methods are time consuming. 相似文献89.
90.
Back BB Baker MD Barton DS Basilev S Bates BD Baum R Betts RR Białas A Bindel R Bogucki W Budzanowski A Busza W Carroll A Ceglia M Chang YH Chen AE Coghen T Conner C Czyz W Dabrowski B Decowski MP Despet M Fita P Fitch J Friedl M Gałuszka K Ganz R Garcia E George N Godlewski J Gomes C Griesmayer E Gulbrandsen K Gushue S Halik J Halliwell C Haridas P Hayes A Heintzelman GA Henderson C Hollis R Hołyński R Holzman B Johnson E Kane J Katzy J Kita W Kotuła J Kraner H Kucewicz W Kulinich P LawV C 《Physical review letters》2000,85(15):3100-3104
We present the first measurement of pseudorapidity densities of primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For the most central collisions, we find the charged-particle pseudorapidity density to be dN/deta|(|eta|<1) = 408+/-12(stat)+/-30(syst) at 56 GeV and 555+/-12(stat)+/-35(syst) at 130 GeV, values that are higher than any previously observed in nuclear collisions. Compared to proton-antiproton collisions, our data show an increase in the pseudorapidity density per participant by more than 40% at the higher energy. 相似文献