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51.
Maysa Tibério Ubrig Maria Valéria S. Goffi-Gomez Raimar Weber Márcia H. Moreira Menezes Nair Kátia Nemr Domingos Hiroshi Tsuji Robinson Koji Tsuji 《Journal of voice》2011,25(6):692-699
Objectives
To ascertain whether cochlear implantation (CI), without specific vocal rehabilitation, is associated with changes in perceptual and acoustic vocal parameters in adults with severe to profound postlingual deafness.Hypothesis
Merely restoring auditory feedback could allow the individual to make necessary adjustments in vocal pattern.Study Design
Prospective and longitudinal.Methods
The experimental group composed of 40 postlingually deaf adults (20 males and 20 females) with no previous laryngeal or voice disorders. Participants’ voices were recorded before CI and 6–9 months after CI. To check for chance modifications between two evaluations, a control group of 12 postlingually deaf adults, six male and six female, without CI was also evaluated. All sessions composed of the recording of read sentences from Consensus Auditory-Perceptual Evaluation of Voice and sustained vowel /a/. Auditory and acoustic analyses were then conducted.Results
We found a statistically significant reduction in overall severity, strain, loudness, and instability in auditory analysis. In vocal acoustic analysis, we found statistically significant reduction fundamental frequency (F0) values (in male participants) and F0 variability (in both genders). The control group showed no statistically significant changes in most vocal parameters assessed, apart from pitch and F0 (in female participants only). On comparing the interval of variation of results between the experimental and control groups, we found no statistically significant difference in vocal parameters between CI recipients and nonrecipients, with the exception of F0 variability in male participants.Conclusions
The patients in our sample showed changes in overall severity, strain, loudness, and instability values, and reductions in F0 and its variability. On comparing the variation of results between the groups, we were able to prove in our study that implant recipients postlingually deaf adults (experimental group), without specific vocal rehabilitation, differed from nonrecipients (control group) in loudness and F0 variability sustained vowel /a/ in male participants. 相似文献52.
Moreira H Yu Q Nadal B Bresson B Rosticher M Lequeux N Zimmers A Aubin H 《Physical review letters》2011,107(17):176803
We describe current-voltage (I-V) characteristics of alkyl-ligated gold nanocrystals ~5 nm arrays in a long screening length limit. Arrays with different alkyl ligand lengths have been prepared to tune the electronic tunnel coupling between the nanocrystals. For long ligands, electronic diffusion occurs through sequential tunneling and follows activated laws, as a function of temperature σ∝e(-T(0)/T) and as a function of electric field I∝e(-E(0)/E). For better conducting arrays, i.e., with small ligands, the transport properties cross over to the cotunneling regime and follow Efros-Shklovskii laws as a function of temperature σ∝e(-(T(ES)/T)(1/2) and as a function of electric field I∝e(-(E)(ES)/E)(1/2). The data show that electronic transport in nanocrystal arrays can be tuned from the sequential tunneling to the cotunneling regime by increasing the tunnel barrier transparency. 相似文献
53.
J. Agostinho Moreira A. Almeida M.R. Chaves J.M. Machado da Silva S.M.F. Vilela 《Solid State Communications》2011,151(5):368-371
This work reports an experimental investigation of the ferroelectric character of magnetic phases of the orthorhombic Eu1−xY xMnO3 system at low temperatures. The temperature dependence of the polarization curves clearly reveals the existence of a re-entrant improper ferroelectric phase for x=0.2, 0.3 and 0.5. A ferroelectric phase is also stable for x=0.4, and we have no experimental evidence for its vanishing down to 7 K. From these and early results obtained using other experimental techniques, the corresponding (x,T) phase diagram was traced, yielding significant differences with regard to the ones previously reported. 相似文献
54.
55.
Roberto Laridondo Lui Daniel Rodrigues Blanco Vladimir Pavan Margarido Orlando Moreira Filho 《Micron (Oxford, England : 1993)》2009,40(5-6):552-559
B chromosomes are considered additional and non-essential; they likely originate from A chromosomes and follow a distinct evolution. In fish, approximately half of the Neotropical species with B chromosomes are Characiformes and 35% are Siluriformes. There has been no report of B chromosomes in Auchenipteridae until this moment. B chromosomes found in a population of Parauchenipterus galeatus from the São Francisco River basin in the state of Minas Gerais (Brazil) were small, metacentric, totally heterochromatic and exhibited intra-individual and inter-individual variation. The diploid number was 58 chromosomes (22 metacentric, 16 submetacentric, 12 subtelocentric and 8 acrocentric). The nucleolar organizing regions were simple and the heterochromatin intercalated in the ribosomal sites, characterized by CMA3 and DAPI fluorochromes, was of a GC-rich constitution. The 5S rDNA genes were located in an intercalary position in only one chromosome pair. An hypothesis about the origin of the B chromosomes in P. galeatus and a review on B chromosomes in catfish are also presented in this study. 相似文献
56.
G. Franzò A. Irrera E.C. Moreira M. Miritello F. Iacona D. Sanfilippo G. Di Stefano P.G. Fallica F. Priolo 《Applied Physics A: Materials Science & Processing》2002,74(1):1-5
We have studied the structural, electrical and optical properties of MOS devices, where the dielectric layer consists of a
substoichiometric SiOx (x<2) thin film deposited by plasma-enhanced chemical vapor deposition. After deposition the samples were annealed at high
temperature (>1000 °C) to induce the separation of the Si and the SiO2 phases with the formation of Si nanocrystals embedded in the insulating matrix. We observed at room temperature a quite intense
electroluminescence (EL) signal with a peak at ∼850 nm. The EL peak position is very similar to that observed in photoluminescence
in the very same device, demonstrating that the observed EL is due to electron–hole recombination in the Si nanocrystals and
not to defects. The effects of the Si concentration in the SiOx layer and of the annealing temperature on the electrical and optical properties of these devices are also reported and discussed.
In particular, it is shown that by increasing the Si content in the SiOx layer the operating voltage of the device decreases and the total efficiency of emission increases. These data are reported
and their implications discussed.
Received: 31 August 2001 / Accepted: 3 September 2001 / Published online: 17 October 2001 相似文献
57.
58.
59.
Fagner Moreira de Oliveira Camila Marchioni Juan A. V de A. Barros Ayla Campos do Lago Célio Wisniewski Pedro Orival Luccas 《Analytica chimica acta》2014
This work presents an evaluation of iron and cadmium adsorption in sediment of the Furnas Hydroelectric Plant Reservatory located in Alfenas, Minas Gerais (Brazil). The metal determination was done employing a flow injection analysis (FIA) with an on-line filtering system. As detection techniques, flame atomic absorption spectrometry (FAAS) for iron and thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) for cadmium determinations were used. The developed methodology presented good limits of detection, being 190 μg L−1 for iron and 1.36 μg L−1 for cadmium, and high sampling frequency for both metals 144 and 60 readings h−1 for iron and cadmium, respectively. Both metals obey the Langmuir model, with maximum adsorptive capacity of 0⋅169 mg g−1 for iron and 7⋅991 mg g−1 for cadmium. For iron, a pseudo-first-order kinetic model was obtained with a theoretical Qe = 9⋅8355 mg g−1 (experimental Qe = 9⋅5432 mg g−1), while for cadmium, a pseudo-second-order kinetic model was obtained, with a theoretical Qe = 0.3123 mg g−1 (experimental Qe = 0⋅3052 mg g−1). 相似文献
60.
Cormanich RA Moreira MA Freitas MP Ramalho TC Anconi CP Rittner R Contreras RH Tormena CF 《Magnetic resonance in chemistry : MRC》2011,49(12):763-767
The present study shows that a hydrogen bond between the OH group and the fluorine atom is not involved in the (1h)J(FH) spin-spin coupling transmission either for 4-bromo-2-fluorophenol or 2-fluorophenol. In fact, according to a quantum theory of atoms in molecules analysis, no bond critical point is found between O-H and F moieties. The nature of the transmission mechanism of the Fermi contact term of the (1h)J(FH) spin-spin coupling is studied by analyzing canonical molecular orbitals (see J. Phys. Chem. A 2010, 114, 1044), and it is observed that virtual orbitals play only a quite minor role in its transmission. This is typical of a Fermi contact term transmitted mainly through exchange interactions owing to the overlap of proximate electronic clouds; therefore, it is suggested to identify them as (nTS)J(FH) coupling where n stands for the number of formal bonds separating the coupling nuclei. In the cases studied in this work is n = 4. Results presented in this work could provide an interesting rationalization for different experimental signs known in the current literature for proximate J(FH) couplings. 相似文献