Speaker-sex discrimination for voiced and whispered vowels at short durations

Whispered vowels, produced with no vocal fold vibration, lack the periodic temporal fine structure which in voiced vowels underlies the perceptual attribute of pitch (a salient auditory cue to speaker sex). Voiced vowels possess no temporal fine structure at very short durations (below two glottal cycles). The prediction was that speaker-sex discrimination performance for whispered and voiced vowels would be similar for very short durations but, as stimulus duration increases, voiced vowel performance would improve relative to whispered vowel performance as pitch information becomes available. This pattern of results was shown for women’s but not for men’s voices. A whispered vowel needs to have a duration three times longer than a voiced vowel before listeners can reliably tell whether it’s spoken by a man or woman (∼30 ms vs. ∼10 ms). Listeners were half as sensitive to information about speaker-sex when it is carried by whispered compared with voiced vowels

Perturbations of C*-algebraic invariants

Kadison and Kastler introduced a metric on the set of all C*-algebras on a fixed Hilbert space. In this paper structural properties of C*-algebras which are close in this metric are examined. Our main result is that the property of having a positive answer to Kadison’s similarity problem transfers to close C*-algebras. In establishing this result we answer questions about closeness of commutants and tensor products when one algebra satisfies the similarity property. We also examine K-theory and traces of close C*-algebras, showing that sufficiently close algebras have isomorphic Elliott invariants when one algebra has the similarity property

Surface modification of a polyether-urethane with RGD-containing peptides for enhanced cell attachment and signalling

Abstract of article examining the chemical modification of polyurethane with RGD-containing peptides offers a means of encouraging the adhesion, spreading and proliferation of cells cultured on its surface. This study assesses the efficacy of a modification procedure using surface analysis techniques and preliminary cell culture studies

Domestic dogs (Canis lupus familiaris) are sensitive to the correlation between pitch and timbre in human speech

The perceived pitch of human voices is highly correlated with the fundamental frequency (f0) of the laryngeal source, which is determined largely by the length and mass of the vocal folds. The vocal folds are larger in adult males than in adult females, and men’s voices consequently have a lower pitch than women’s. The length of the supralaryngeal vocal tract (vocal-tract length; VTL) affects the resonant frequencies (formants) of speech which characterize the timbre of the voice. Men’s longer vocal tracts produce lower frequency, and less dispersed, formants than women’s shorter vocal tracts. Pitch and timbre combine to influence the perception of speaker characteristics such as size and age. Together, they can be used to categorize speaker sex with almost perfect accuracy. While it is known that domestic dogs can match a voice to a person of the same sex, there has been no investigation into whether dogs are sensitive to the correlation between pitch and timbre. We recorded a female voice giving three commands (‘Sit’, ‘Lay down’, ‘Come here’), and manipulated the recordings to lower the fundamental frequency (thus lowering pitch), increase simulated VTL (hence affecting timbre), or both (synthesized adult male voice). Dogs responded to the original adult female and synthesized adult male voices equivalently. Their tendency to obey the commands was, however, reduced when either pitch or timbre was manipulated alone. These results suggest that dogs are sensitive to both the pitch and timbre of human voices, and that they learn about the natural covariation of these perceptual attributes

Delayed winter supplemental feeding and year-round mineral supplementation of beef cows on native range

Polled Hereford cows on native Flint Hills pasture not supplemented until February lost more weight from December to February, lost less from February to May, and were in poorer condition before calving than cows supplemented beginning in November. But calf survival, birth weight, and calf average daily gain were similar for both groups. Feeding cows a calcium, phosphorus, trace mineral mix did not improve any measure of cow or calf performance

Response of yearling steers to burning and fertilizing pasture and intensive early season stocking (bluestem pastures)

Nine pastures totaling 492 acres were summer grazed by yearling Hereford, Hereford-Angus cross, and Angus steers distributed equally by breed. Five pastures were burned April 22, 1975; four were not burned. Burned and nonburned pastures had 0, 40, or 80 lbs. of nitrogen per acre applied aerially April 29, 1975. Stocking rates were determined with herbage production data from experimental plots under similar treatments. Under equal fertilization and stocking ratios, burned and fertilized pastures produced as much or more average daily gain and more gain per acre than nonburned pastures. Fertilizing and heavier stocking tended to reduce average daily gains but increased gains per acre. Steers on the early season, intensely-stocked pasture gained the most per day (1.78 lbs.) and produced the highest gain per acre (70 lbs.)

Aloidendron barberae

Aloidendron is a very small genus of seven tree aloes in the family Asphodelaceae, described as recently as 2013, ranging from South Africa to Mozambique, with a large disjunction to Somalia, Yemen and Saudi Arabia. Aloidendron barberae is recorded from South Africa, Swaziland and southern Mozambique. However, the records for Mozambique are queried here and it is suggested that these actually relate to its closest relative, Aloidendron tongaense, a smaller tree only 4-8 m tall, which may be endemic to Mozambique. Aloidendron barberae is the largest alooid, growing to 20 m tall and is copiously dichotomously branched. Its taxonomic and nomenclatural history are outlined. Its habitat, natural distribution, ecology and cultivation are discussed, accompanied by a full description and reproduction of a specially commissioned watercolour painting