Familial hypertrophic cardiomyopathy in maine coon cats: an animal model of human disease.

BACKGROUND: A naturally occurring animal model of familial hypertrophic cardiomyopathy (FHCM) is lacking. We identified a family of Maine coon cats with HCM and developed a colony to determine mode of inheritance, phenotypic expression, and natural history of the disease. METHODS AND RESULTS: A proband was identified, and related cats were bred to produce a colony. Affected and unaffected cats were bred to determine the mode of inheritance. Echocardiography was used to identify affected offspring and determine phenotypic expression. Echocardiograms were repeated serially to determine the natural history of the disease. Of 22 offspring from breeding affected to unaffected cats, 12 (55%) were affected. When affected cats were bred to affected cats, 4 (45%) of the 9 were affected, 2 (22%) unaffected, and 3 (33%) stillborn. Findings were consistent with an autosomal dominant mode of inheritance with 100% penetrance, with the stillborns representing lethal homozygotes that died in utero. Affected cats usually did not have phenotypic evidence of HCM before 6 months of age, developed HCM during adolescence, and developed severe HCM during young adulthood. Papillary muscle hypertrophy that produced midcavitary obstruction and systolic anterior motion of the mitral valve was the most consistent manifestation of HCM. Cats died suddenly (n=5) or of heart failure (n=3). Histopathology of the myocardium revealed myocardial fiber disarray, intramural coronary arteriosclerosis, and interstitial fibrosis. CONCLUSIONS: HCM in this family of Maine coon cats closely resembles the human form of FHCM and should prove a valuable tool for studying the gross, cellular, and molecular pathophysiology of the disease.

Processing time, accent, and comprehensibility in the perception of native and foreign-accented speech.

In this study, a sentence verification task was used to determine the effect of a foreign accent on sentence processing time. Twenty native English listeners heard a set of English true/false statements uttered by ten native speakers of English and ten native speakers of Mandarin. The listeners assessed the truth value of the statements, and assigned accent and comprehensibility ratings. Response latency data indicated that the Mandarin-accented utterances required more time to evaluate than the utterances of the native English speakers. Furthermore, utterances that were assigned low comprehensibility ratings tended to take longer to process than moderately or highly comprehensible utterances. However, there was no evidence that degree of accent was related to processing time. The results are discussed in terms of the "costs" of speaking with a foreign accent, and the relevance of such factors as accent and comprehensibility to second language teaching.

Factors affecting strength of perceived foreign accent in a second language.

This study assessed the relation between non-native subjects' age of learning (AOL) English and the overall degree of perceived foreign accent in their production of English sentences. The 240 native Italian (NI) subjects examined had begun learning English in Canada between the ages of 2 and 23 yr, and had lived in Canada for an average of 32 yr. Native English-speaking listeners used a continuous scale to rate sentences spoken by the NI subjects and by subjects in a native English comparison group. Estimates of the AOL of onset of foreign accents varied across the ten listeners who rated the sentences, ranging from 3.1 to 11.6 yr (M = 7.4). Foreign accents were evident in sentences spoken by many NI subjects who had begun learning English long before what is traditionally considered to be the end of a critical period. Very few NI subjects who began learning English after the age of 15 yr received ratings that fell within the native English range. Principal components analyses of the NI subjects' responses to a language background questionnaire were followed by multiple-regression analyses. AOL accounted for an average of 59% of variance in the foreign accent ratings. Language use factors accounted for an additional 15% of variance. Gender was also found to influence degree of foreign accent.

The perception of English and Spanish vowels by native English and Spanish listeners: a multidimensional scaling analysis.

A group of Spanish- and English-speaking listeners participated in a multidimensional scaling (MDS) study examining perceptual responses to three Spanish and seven English vowels. The vowel stimuli represented tokens of Spanish /i/, /e/, and /a/ and English /i/, /I/, /eI/, /epsilon/, /ae/, /lambda/, and /a/. Each vowel had been spoken by three monolingual talkers of Spanish or English and all possible vowel pairs (405 pairs) were presented to listeners (excluding pairs representing the same vowel category). Thirty monolingual English listeners and thirty native Spanish listeners who had learned English as a second language rated these vowel pairs on a nine-point dissimilarity scale. These perceptual distances were then analyzed using then individual-differences version of ALSCAL. Results demonstrated that the English monolinguals used three underlying dimensions in rating vowels while the Spanish-English bilinguals used just two. The most salient perceptual dimension for both groups distinguished vowel height. However, for the English listeners, this dimension was most significantly correlated with duration and indicated a language-dependent sensitivity to this phonetic feature. The second dimension for the English listeners represented a front-back distinction, while the third reflected a central/noncentral distinction. For the Spanish listeners, the second dimension was less easily interpreted. However, the perceptual data for the Spanish listeners was more interpretable in terms of the distribution of the vowels in the two-dimensional perceptual plane. The vowels were distributed in terms of three separate vowel clusters, each cluster near the location of a Spanish vowel.(ABSTRACT TRUNCATED AT 250 WORDS)

Auditory and categorical effects on cross-language vowel perception.

English monolinguals and native Spanish speakers of English rated the dissimilarity of tokens of two Spanish vowel categories, two English vowel categories, or one Spanish and one English vowel category. The dissimilarity ratings of experienced and inexperienced Spanish subjects did not differ significantly. For both the native Spanish and English subjects, perceived dissimilarity increased as the distance between vowels in an F1-F2 acoustic space increased. This supported the existence of a universal, sensory-based component in cross-language vowel perception. The native English and Spanish subjects' ratings were comparable for pairs made up of vowels that were distant in an F1-F2 space, but not for pairs made up of vowels from categories that were adjacent in an F1-F2 space. The inference that the differential classification of a pair of vowels augments perceived dissimilarity was supported by the results of experiment 2, where subjects rated pairs of vowels and participated in an oddity discrimination task. Triads in the oddity task were made up of tokens of vowel categories that were either adjacent (e.g., /a/-/ae/-/a/) or nonadjacent (e.g., /a/-/i/-/i/) in an F1-F2 space. The native English subjects' discrimination was better than the native Spanish subjects' for adjacent but not nonadjacent triads. The better the Spanish subjects performed on adjacent triads--and thus the more likely they were to have differentially classified the two phonetically distinct vowels in the triad--the more dissimilar they had earlier judged realizations of those two categories to be when presented in pairs. Results are discussed in terms of their implications for second language acquisition.

Productions of English vowels by native speakers of Arabic: acoustic measurements and accentedness ratings.

Productions of ten English vowels in /bVt/ and /bVd/ contexts were elicited from a group of native American English speakers and a group of native Arabic speakers who had learned English in adulthood. When a variety of acoustic measurements, including vowel durations, F1 and F2 frequencies, and movement in F1 and F2 were examined, the two groups were found to differ on at least one of these parameters for nearly every vowel considered. A subset of the Arabic speakers' productions, and the productions of two native English speakers, were rated for accentedness by five native English judges. The rating data indicated that only a minority of the Arabic group's productions were regarded by the judges as "native-like". When the acoustic measurement data were regressed on the mean ratings, it was found that the accentedness scores were correlated primarily with F1 frequency and movement in F2, although the significant predictors varied from vowel to vowel.

Production of the word-final English /t/-/d/ contrast by native speakers of English, Mandarin, and Spanish.

The primary aim of this study was to determine if adults whose native language permits neither voiced nor voiceless stops to occur in word-final position can master the English word-final /t/-/d/ contrast. Native English-speaking listeners identified the voicing feature in word-final stops produced by talkers in five groups: native speakers of English, experienced and inexperienced native Spanish speakers of English, and experienced and inexperienced native Mandarin speakers of English. Contrary to hypothesis, the experienced second language (L2) learners' stops were not identified significantly better than stops produced by the inexperienced L2 learners; and their stops were correctly identified significantly less often than stops produced by the native English speakers. Acoustic analyses revealed that the native English speakers made vowels significantly longer before /d/ than /t/, produced /t/-final words with a higher F1 offset frequency than /d/-final words, produced more closure voicing in /d/ than /t/, and sustained closure longer for /t/ than /d/. The L2 learners produced the same kinds of acoustic differences between /t/ and /d/, but theirs were usually of significantly smaller magnitude. Taken together, the results suggest that only a few of the 40 L2 learners examined in the present study had mastered the English word-final /t/-/d/ contrast. Several possible explanations for this negative finding are presented. Multiple regression analyses revealed that the native English listeners made perceptual use of the small, albeit significant, vowel duration differences produced in minimal pairs by the nonnative speakers. A significantly stronger correlation existed between vowel duration differences and the listeners' identifications of final stops in minimal pairs when the perceptual judgments were obtained in an "edited" condition (where post-vocalic cues were removed) than in a "full cue" condition. This suggested that listeners may modify their identification of stops based on the availability of acoustic cues.

Perception of 'voicing' in whispered stops.

Amplitude measurements of 32 whispered tokens of /p/ and /b/ produced in four vowel contexts revealed that whispered /b/ tended to have a steeper rise slope relative to the following vowel than did /p/. In a perceptual experiment, short (60-ms) whispered stop + vowel utterances were played to 8 listeners. Their identification scores were significantly above chance, but lower than what might be expected for stop + vowel stimuli produced with normal voicing. The pattern of identifications showed no relationship to the measured rise time differences.

Seeking aids counsellors.

I have recently been appointed AIDS Co-ordinator for Advice and Counselling in this district and would be most interested to hear from any other people with similar backgrounds to my own who hold similar posts.