2,713 research outputs found
Phonetic content influences voice discriminability
We present results from an experiment which shows that voice perception is influenced by the phonetic content of speech. Dutch listeners were presented with thirteen speakers pronouncing CVC words with systematically varying segmental content, and they had to discriminate the speakers’ voices. Results show that certain segments help listeners discriminate voices more than other segments do. Voice information can be extracted from every segmental position of a monosyllabic word and is processed rapidly. We also show that although relative discriminability within a closed set of voices appears to be a stable property of a voice, it is also influenced by segmental cues – that is, perceived uniqueness of a voice depends on what that voice says
Dosage compensation in birds
AbstractThe Z and W sex chromosomes of birds have evolved independently from the mammalian X and Y chromosomes [1]. Unlike mammals, female birds are heterogametic (ZW), while males are homogametic (ZZ). Therefore male birds, like female mammals, carry a double dose of sex-linked genes relative to the other sex. Other animals with nonhomologous sex chromosomes possess “dosage compensation” systems to equalize the expression of sex-linked genes. Dosage compensation occurs in animals as diverse as mammals, insects, and nematodes, although the mechanisms involved differ profoundly [2]. In birds, however, it is widely accepted that dosage compensation does not occur [3–5], and the differential expression of Z-linked genes has been suggested to underlie the avian sex-determination mechanism [6]. Here we show equivalent expression of at least six of nine Z chromosome genes in male and female chick embryos by using real-time quantitative PCR [7]. Only the Z-linked ScII gene, whose ortholog in Caenorhabditis elegans plays a crucial role in dosage compensation [8], escapes compensation by this assay. Our results imply that the majority of Z-linked genes in the chicken are dosage compensated
Scaling and data collapse from local moments in frustrated disordered quantum spin systems
Recently measurements on various spin-1/2 quantum magnets such as
HLiIrO, LiZnMoO, ZnCu(OH)Cl and 1T-TaS
-- all described by magnetic frustration and quenched disorder but with no
other common relation -- nevertheless showed apparently universal scaling
features at low temperature. In particular the heat capacity C[H,T] in
temperature T and magnetic field H exhibits T/H data collapse reminiscent of
scaling near a critical point. Here we propose a theory for this scaling
collapse based on an emergent random-singlet regime extended to include
spin-orbit coupling and antisymmetric Dzyaloshinskii-Moriya (DM) interactions.
We derive the scaling with at small , with (0,1,2) an integer exponent whose value
depends on spatial symmetries. The agreement with experiments indicates that a
fraction of spins form random valence bonds and that these are surrounded by a
quantum paramagnetic phase. We also discuss distinct scaling for magnetization
with a -dependent subdominant term enforced by Maxwell's relations.Comment: v2. Expanded argument in Appendix 2 and revised for clarity. v3.
Fixed typo in Fig 3 caption. Main text 4 pages 4 figures, Appendix 6 pages 1
figur
Retrofitting of Conditioning Systems for Existing Small Commercial Buildings - Analysis and Design of Liquid Desiccant - Vapor Compression Hybrid
The combination of several concepts of new energy technologies may make it possible to reduce the energy
needs for thermal comfort, especially cooling and dehumidification, in small sized, single-story commercial
buildings. The potentials and limitations of retrofit technology for these characteristic structures have
been the focus of the experience gained through the design and installation of a system adapted to a building
constructed in the early 1960's. The existing split package air conditioning system was combined with a
desiccant air-conditioning unit with a waste heat and solar heat reclaim component. While this retrofit
system is feasible, a number of questions remain to be considered regarding the design, installation and
operation of the total system. This paper focuses on the practical applications of such a hybrid system -
both architectural/construction issues and the mechanical components/system considerations
The locus of talker-specific effects in spoken-word recognition
Words repeated in the same voice are better recognized than when they are repeated in a different voice. Such findings have been taken as evidence for the storage of talker-specific lexical episodes. But results on perceptual learning suggest that talker-specific adjustments concern sublexical representations. This study thus investigates whether voice-specific repetition effects in auditory lexical decision are lexical or sublexical. The same critical set of items in Block 2 were, depending on materials in Block 1, either same-voice or different-voice word repetitions, new words comprising re-orderings of phonemes used in the same voice in Block 1, or new words with previously unused phonemes. Results show a benefit for words repeated by the same talker, and a smaller benefit for words consisting of phonemes repeated by the same talker. Talker-specific information thus appears to influence word recognition at multiple representational levels
Iron Displacements and Magnetoelastic Coupling in the Spin-Ladder Compound BaFe2Se3
We report long-range ordered antiferromagnetism concomitant with local iron
displacements in the spin-ladder compound BaFeSe. Short-range magnetic
correlations, present at room temperature, develop into long-range
antiferromagnetic order below T = 256 K, with no superconductivity down to
1.8 K. Built of ferromagnetic Fe plaquettes, the magnetic ground state
correlates with local displacements of the Fe atoms. These iron displacements
imply significant magnetoelastic coupling in FeX-based materials, an
ingredient hypothesized to be important in the emergence of superconductivity.
This result also suggests that knowledge of these local displacements is
essential for properly understanding the electronic structure of these systems.
As with the copper oxide superconductors two decades ago, our results highlight
the importance of reduced dimensionality spin ladder compounds in the study of
the coupling of spin, charge, and atom positions in superconducting materials
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