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171.
Both dyslexics and auditory neuropathy (AN) subjects show inferior consonant-vowel (CV) perception in noise, relative to controls. To better understand these impairments, natural acoustic speech stimuli that were masked in speech-shaped noise at various intensities were presented to dyslexic, AN, and control subjects either in isolation or accompanied by visual articulatory cues. AN subjects were expected to benefit from the pairing of visual articulatory cues and auditory CV stimuli, provided that their speech perception impairment reflects a relatively peripheral auditory disorder. Assuming that dyslexia reflects a general impairment of speech processing rather than a disorder of audition, dyslexics were not expected to similarly benefit from an introduction of visual articulatory cues. The results revealed an increased effect of noise masking on the perception of isolated acoustic stimuli by both dyslexic and AN subjects. More importantly, dyslexics showed less effective use of visual articulatory cues in identifying masked speech stimuli and lower visual baseline performance relative to AN subjects and controls. Last, a significant positive correlation was found between reading ability and the ameliorating effect of visual articulatory cues on speech perception in noise. These results suggest that some reading impairments may stem from a central deficit of speech processing. 相似文献
172.
Dobbs S Metreveli Z Seth KK Tomaradze A Zweber P Ernst J Mahmood AH Severini H Asner DM Dytman SA Love W Mehrabyan S Mueller JA Savinov V Li Z Lopez A Mendez H Ramirez J Huang GS Miller DH Pavlunin V Sanghi B Shibata EI Shipsey IP Adams GS Chasse M Cravey M Cummings JP Danko I Napolitano J Cronin-Hennessy D Park CS Park W Thayer JB Thorndike EH Coan TE Gao YS Liu F Artuso M Boulahouache C Blusk S Butt J Dambasuren E Dorjkhaidav O Menaa N Mountain R Muramatsu H Nandakumar R Redjimi R Sia R 《Physical review letters》2005,94(3):032004
We report on a search for the recently reported X(3872) state using 15.1 fb(-1) of e(+)e(-) data taken in the sqrt[s] = 9.46-11.30 GeV region. Separate searches for the production of the X(3872) in untagged gammagamma fusion and e(+)e(-) annihilation following initial state radiation are made by taking advantage of the unique angular correlation between the leptons from the decay J/psi --> l(+)l(-) in X(3872) decay to pi(+)pi(-)J/psi. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)Gamma(gammagamma)(X(3872))B(X --> pi(+)pi(-)J/psi) < 12.9 eV and Gamma(ee)(X(3872))B(X- -> pi(+)pi(-)J/psi) < 8.3 eV. 相似文献
173.
The behavior of 4-nitrophenyl dihydrogen phosphate, ArOPO3H2, and of its tetra-n-butylammonium and tetramethylammonium salts, ArOPO3H?R4N+, ArOPO32?2(R4N+), was studied in aprotic solvents, in the absence and in the presence of increasing amounts of alcohols or water. The reactions were investigated in the absence of amines, and in the presence of hindered and unhindered amines, diisopropylethylamine and quinuclidine. The course of the reactions was followed at 35° or at 70° by 31P and 1H NMR spectrometry. Values for the approximate half-times of the reactions were estimated (± 25 %) from the times at which reactant signal intensity becomes equal to product signal intensity. The mononitrophenyl ester transfers its phosphoryl group to alcohols and water from the diprotonated acid by the addition-elimination mechanism via oxyphosphorane intermediates, and from the monoanion and dianion by the elimination-addition mechanism via the monomeric metaphosphate intermediate, PO3?. Formation of PO3? is faster from dianion than from monoanion in acetonitrile and in alcohol solutions. Conversely, PO3? is generated at a faster rate from monoanion than from dianion in aqueous solution. This effect results from a decrease in the rate of formation of PO3? in the solvent series: acetonitrile > alcohols > water. The rate depression as a function of the medium is greater for the dianion than for the monoanion, and is attributed to greater solvation of the more polar phosphate ground state than of the less polar transition state in the more polar protic solvents. Unhindered amines add to 4-nitrophenyl phosphate monoanion, but not to the dianion. The oxyphosphorane intermediate thus formed collapses to aroxide ion and a protonated dipolar phosphoramide which is rapidly deprotonated by the relatively basic 4-nitrophenoxide: ArOPO3H? + CH(CH2CH2)3N(acetonitrile ? CH(CH2CH2)3N+P(O)(OH)O? + ArO?? CH(CH2 CH2)3N+PO32?+ ArOH → CH(CH2CH2)3N + PO3?. The postulated formation of PO3? by this route explains why the addition of quinuclidine to an acetonitrile solution containing the monoanion salt, ArOPO3H?R4N+, and t?BuOH produces t-butyl phosphate at a faster rate than the addition of diisopropylethylamine to the same solution. 2,4-Dinitrophenyl phosphate, which was previously studied by the same techniques, reacts via oxyphosphorane intermediates from the diprotonated and the monoanion forms, and via monomeric metaphosphate, from the dianion form. 相似文献
174.
175.
Daniel A. Ramirez Jianxing Zhang Kevin Klausmeyer Robert R. Kane 《Journal of chemical crystallography》2005,35(3):227-232
The combretastatin A-4 analogue cis-1-(3-N,N-dimethylthiocarbamoyl-4-methoxy)-2-(3,4, 5-trimethoxyphenyl) ethene (1) and its trans stereoisomer (2) were synthesized. The molecular structures of these compounds were obtained by single-crystal X-ray diffraction. Crystallization of 1 occurs in the centrosymmetric monoclinic space group C2/c (No. 15) with a = 21.468(5), b = 7.932(1), c = 23.949(3); and = 100.75(1) and Z = 8. Crystallization of 2 occurs in the centrosymmetric monoclinic space group P21/n (No. 14) with a = 11.7825(7), b = 11.562(1), c = 14.911(1) and = 93.294(6); and Z = 4. Details of the synthesis and the structural characterization of the title compounds are presented and discussed. 相似文献
176.
177.
This paper formulates a new criterion that distinguishes the set of parametric methods within the set of all the divisor methods of apportionment. The criterion—that a method transfer seats as it “should”—asks that as population (or the votes of parties in a PR system) is shifted more and more from one state to another state (from one party to another party) at some point the first state (or party) is apportioned one less seat, the second state (or party) one more seat, and the remaining apportionments are as they were. It goes on to examine several properties of parametric methods. 相似文献
178.
Premaditya Chhetri Dieter Ackermann Hartmut Backe Michael Block Bradley Cheal Christoph Emanuel Düllmann Julia Even Rafael Ferrer Francesca Giacoppo Stefan Götz Fritz Peter Heßberger Oliver Kaleja Jadambaa Khuyagbaatar Peter Kunz Mustapha Laatiaoui Felix Lautenschläger Werner Lauth Enrique Minaya Ramirez Andrew Kishor Mistry Sebastian Raeder Calvin Wraith Thomas Walther Alexander Yakushev 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2017,71(7):195
179.
Managing the spread of alfalfa stem nematodes (Ditylenchus dipsaci): The relationship between crop rotation periods and pest reemergence
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Alfalfa is a critical cash/rotation crop in the western region of the United States, where it is common to find crops affected by the alfalfa stem nematode (ASN) (Ditylenchus dipsaci). Understanding the spread dynamics associated with this pest would allow growers to design better management programs and farming practices. This understanding is of particular importance given that there are no nematicides available against ASNs and control strategies largely rely on crop rotation to nonhost crops or by planting resistant varieties of alfalfa. In this paper, we present a basic host‐parasite model that describes the spread of the ASN on alfalfa crops. With this discrete time model, we are able to portray a relationship between the length of crop rotation periods and the time at which the density of nematode‐infested plants becomes larger than that of nematode‐free ones in the postrotation alfalfa. The numerical results obtained are consistent with farming practice observations, suggesting that the model could play a role in the evaluation of management strategies. 相似文献
180.
MZDASoft: a software architecture that enables large‐scale comparison of protein expression levels over multiple samples based on liquid chromatography/tandem mass spectrometry
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