1,229 research outputs found

    Voice parameters predict sex-specific body morphology in men and women

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    Studies of several mammalian species confirm that formant frequencies (vocal tract resonances) predict height and weight better than does fundamental frequency (F0, perceived as pitch) in same-sex adults due to differential anatomical constraints. However, our recent meta-analysis (Pisanski et al., 2014, Animal Behaviour, 95, 89–99) indicated that formants and F0 could explain no more than 10% and 2% of the variance in human height, respectively, controlling for sex and age. Here, we examined whether other voice parameters, many of which are affected by sex hormones, can indicate additional variance in human body size or shape, and whether these relationships differ between the sexes. Using a cross-cultural sample of 700 men and women, we examined relationships among 19 voice parameters (minimum–maximum F0, mean F0, F0 variability, formant-based vocal tract length estimates, shimmer, jitter, harmonics-to-noise ratio) and eight indices of body size or shape (height, weight, body mass index, hip, waist and chest circumferences, waist-to-hip ratio, chest-to-hip ratio). Our results confirm that formant measures explain the most variance in heights and weights of men and women, whereas shimmer, jitter and harmonics-to-noise ratio do not indicate height, weight or body mass index in either sex. In contrast, these perturbation and noise parameters, in addition to F0 range and variability, explained more variance in body shape than did formants or mean F0, particularly among men. Shimmer or jitter explained the most variance in men's hip circumferences (12%) and chest-to-hip ratios (6%), whereas harmonics-to-noise ratio and formants explained the most variance in women's waist-to-hip ratios (11%), and significantly more than in men's waist-to-hip ratios. Our study represents the most comprehensive analysis of vocal indicators of human body size to date and offers a foundation for future research examining the hormonal mechanisms of voice production in humans and perceptual playback experiments

    Rethinking the test: functional and evolutionary implications

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    Ecological and Biological Response of Benthic Foraminifera Under Oxygen-Depleted Conditions: Evidence from Laboratory Approaches

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    Laboratory experiments are a valuable way to elucidate physiological and ecological processes of benthic foraminifera under oxygen-depleted conditions. Experimentally tested survival rates and other experiments show high tolerance of many species under low oxic to anoxic conditions. Laboratory observations raised different assumptions to explain the physiological adaptations to this tolerance. Denitrification processes seem to be one important mechanism. Nevertheless, foraminifera try to colonize sediment horizons with optimal species-specific oxygen concentrations. Experimental settings demonstrated the importance of oxygen gradients for the orientation in sediments. At the same time, foraminifera change the oxygen concentration in their microenvironment by respiration. Despite high bioturbation, they do not appear to influence the flux of oxygen into the sediment. Experimental working in oxygen-depleted environments needs a reliable determination of living foraminifera during the experiment, e.g., different biochemical techniques. Additionally, electrochemical or optical oxygen sensors that measure the oxygen concentration are necessary

    Magnetic Field induced Dimensional Crossover Phenomena in Cuprate Superconductors and their Implications

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    We discuss the occurrence of crossing points in the magnetization - temperature (m,T(m,T) plane within the framework of critical phenomena. It is shown that in a two-dimensional superconducting slab of thickness dsd_{s} mz(δ)m_{z}(\delta) versus temperature TT curves measured in different fields H=H(0,sin(δ),cos(δ))\mathbf{H} = H(0,\sin (\delta) ,\cos (\delta)) will cross at the critical temperature T_c of the slab. In contrast, in a 3D anisotropic bulk superconductor the crossing point occurs in the plot mz(δ)/Hz1/2m_{z}(\delta) /H_{z}^{1/2} versus TT. The experimental facts that 2D crossing point features have been observed in ceramics and in single crystals for H\mathbf{H} close to H=H(0,0,1)\mathbf{H} = H(0,0,1), but not for H=H(0,1,0)\mathbf{H} = H(0,1,0), is explained in terms of an angle-dependent crossover field separating the regions where 2D or 3D thermal fluctuations dominate. The measured 2D-crossing point data are used to estimate one of the fundamental parameters of cuprate superconductors, the minimum thickness of the slab (ds)(d_{s}), which remains superconducting. Our estimates, based on experimental 2D-crossing point data for single crystals, reveal that this length adopts material dependent values. Therefore, experimental data for T_c and λ2(T=0)\lambda_{\Vert}^{2}(T=0), plotted in terms of T_c versus 1/λ2(T=0)1/\lambda_{\Vert}^{2}(T=0) will not tend to a straight line with universal slope as the underdoped limit is approached. Implications for magnetic torque measurements are also worked out

    Quality Control Process for EQ-5D-5L Valuation Studies

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    Background: The values of the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) are elicited using composite time trade-off and discrete choice experiments. Unfortunately, data quality issues and interviewer effects were observed in the first few EQ-5D-5L valuation studies. To prevent these issues from occurring in later studies, the EuroQol Group established a cyclic quality control (QC) process. Objectives: To describe this QC process and show its impact on data quality. Methods: A newly developed QC tool provided information about protocol compliance, interviewer effects, and mean values by health state severity. In a cyclic process, this information is initially used to evaluate whether new interviewers meet minimal quality requirements and later to provide feedback about how their performance may be improved. To investigate the impact of this cyclic process, we compared the quality of the data in Dutch and Spanish valuation studies that did not have this QC process with that in the follow-up studies in the same countries that used the QC process. Data quality was measured using protocol violations, variability between interviewers, the proportion of inconsistent responders, and clustering of composite time trade-off values. Results: In Spain, protocol violations were reduced from 87% in the valuation study to 5% in the follow-up study and in the Netherlands from 20% to 8%. In both countries, interviewers performed more homogeneously in the follow-up studies. The number of inconsistent respondents was reduced by 23.2% in Spain and 23.6% in the Netherlands. Values were less clustered in the follow-up studies. Conclusions: The implementation of a strict QC process in EQ-5D-5L valuation studies increases interviewer protocol compliance and promotes data quality

    On the determination of the interface density of states in a-Si:H/a-SiC:H multilayers

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    This paper deals with the determination of the interface density of states in amorphous silicon-based multilayers. Photothermal deflection spectroscopy is used to characterize two series of aSi:H/aSi1-xCx:H multilayers, and a new approach in the treatment of experimental dada is used in order to obtain accurate results. From this approach, an upper limit of 10^10 cm-2 is determined for the interface density of states

    Structural and Magnetic Instabilities of La2x_{2-x}Srx_xCaCu2_2O6_6

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    A neutron scattering study of nonsuperconducting La2x_{2-x}Srx_xCaCu2_2O6_6 (x=0 and 0.2), a bilayer copper oxide without CuO chains, has revealed an unexpected tetragonal-to-orthorhombic transition with a doping dependent transition temperature. The predominant structural modification below the transition is an in-plane shift of the apical oxygen. In the doped sample, the orthorhombic superstructure is strongly disordered, and a glassy state involving both magnetic and structural degrees of freedom develops at low temperature. The spin correlations are commensurate.Comment: published versio

    Survival, Reproduction and Calcification of Three Benthic Foraminiferal Species in Response to Experimentally Induced Hypoxia

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    An experiment was conducted to test the survival rates, growth (calcification), and reproduction capacities of three benthic foraminiferal species (Ammonia tepida, Melonis barleeanus and Bulimina marginata) under strongly oxygen-depleted conditions alternating with short periods of anoxia. Protocols were determined to use accurate methods (1) to follow oxygen concentrations in the aquaria (continuously recorded using microsensors), (2) to distinguish live foraminifera (fluorogenic probe), (3) to determine foraminiferal growth (calcein-marked shells and automatic measurement of the shell size). Our results show a very high survival rate, and growth of A. tepida and M. barleeanus in all experimental conditions, suggesting that survival and growth are not negatively impacted by hypoxia. Unfortunately, no reproduction was observed for these species, so that we cannot draw firm conclusions on their ability to reproduce under hypoxic/anoxic conditions. The survival rates of Bulimina marginata are much lower than for the other two species. In the oxic treatments, the presence of juveniles is indicative of reproductive events, which can explain an important part of the mortality. The absence of juveniles in the hypoxic/anoxic treatments could indicate that these conditions inhibit reproduction. Alternatively, the perceived absence of juveniles could also be due to the fact that the juveniles resulting from reproduction (causing similar mortality rates as in the oxic treatments) were not able to calcify, and remained at a propagule stage. Additional experiments are needed to distinguish these two options

    Effect of a Normal-State Pseudogap on Optical Conductivity in Underdoped Cuprate Superconductors

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    We calculate the c-axis infrared conductivity σc(ω)\sigma_c(\omega) in underdoped cuprate superconductors for spinfluctuation exchange scattering within the CuO2_2-planes including a phenomenological d-wave pseudogap of amplitude EgE_g. For temperatures decreasing below a temperature TEg/2T^* \sim E_g/2, a gap for ω<2Eg\omega < 2E_g develops in σc(ω)\sigma_c(\omega) in the incoherent (diffuse) transmission limit. The resistivity shows 'semiconducting' behavior, i.e. it increases for low temperatures above the constant behavior for Eg=0E_g=0. We find that the pseudogap structure in the in-plane optical conductivity is about twice as big as in the interplane conductivity σc(ω)\sigma_c(\omega), in qualitative agreement with experiment. This is a consequence of the fact that the spinfluctuation exchange interaction is suppressed at low frequencies as a result of the opening of the pseudogap. While the c-axis conductivity in the underdoped regime is described best by incoherent transmission, in the overdoped regime coherent conductance gives a better description.Comment: to be published in Phys. Rev. B (November 1, 1999

    C-axis lattice dynamics in Bi-based cuprate superconductors

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    We present results of a systematic study of the c axis lattice dynamics in single layer Bi2Sr2CuO6 (Bi2201), bilayer Bi2Sr2CaCu2O8 (Bi2212) and trilayer Bi2Sr2Ca2Cu3O10 (Bi2223) cuprate superconductors. Our study is based on both experimental data obtained by spectral ellipsometry on single crystals and theoretical calculations. The calculations are carried out within the framework of a classical shell model, which includes long-range Coulomb interactions and short-range interactions of the Buckingham form in a system of polarizable ions. Using the same set of the shell model parameters for Bi2201, Bi2212 and Bi2223, we calculate the frequencies of the Brillouin-zone center phonon modes of A2u symmetry and suggest the phonon mode eigenvector patterns. We achieve good agreement between the calculated A2u eigenfrequencies and the experimental values of the c axis TO phonon frequencies which allows us to make a reliable phonon mode assignment for all three Bi-based cuprate superconductors. We also present the results of our shell model calculations for the Gamma-point A1g symmetry modes in Bi2201, Bi2212 and Bi2223 and suggest an assignment that is based on the published experimental Raman spectra. The superconductivity-induced phonon anomalies recently observed in the c axis infrared and resonant Raman scattering spectra in trilayer Bi2223 are consistently explained with the suggested assignment.Comment: 29 pages, 13 figure
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