Does number of volumes affect regional deformation measurements when using volume stitched 3D speckle tracking?

Funding Acknowledgements Type of funding sources: None. Background Optimal 3D speckle tracking echocardiography (STE) requires volume stitching, a technique prone to errors, such as patient movements, respiration and arrhythmias. With different resolution at different depths (Figure 1A), such errors may cause stitching artefacts that affect STE derived deformation measurements at different levels of the left ventricle. Methods In this cross-sectional study, 62 patients with variable degree of aortic stenosis participated. 3D images were recorded using 3 different methods (2-, 4- and 6-beat volume stitching at 22 ± 2, 29 ± 4 and 36 ± 6 volumes per second, respectively). Strain, rotation and torsion were analyzed at 3 different levels (basal, mid and apical) (Figure 1B). Results were compared using one-way analysis of variance between methods. Inter-segmental variation was estimated using the coefficient of variation (CV) of the segments involved for each level. Results were interpreted as more accurate if low values of inter-segmental variation between segments in a level was present. Results Neither longitudinal strain (LS) nor circumferential strain (CS) showed any difference between methods in the basal level (Table 1). LS was higher in mid and apical level for 2-beat, while CS was higher only in apical level for 2-beat. Inter-segmental CV showed no significant difference between methods for LS and CS. Between levels, both had higher CV in basal than apical level, but CS had much higher values, indicating lower accuracy in basal level. Rotation measurements showed negative values in basal level and positive in apical level. None of the methods differed significantly. Torsion showed higher values for 2 beat images only. Conclusion 3D STE from both 4- and 6 beat images have insignificant differences for strain, as well as low inter-segmental variability. LS is accurate in all levels while CS has high accuracy in apical, and poor in basal level. Both rotation and torsion differ insignificantly when using 4- and 6-beat images. Table 1 Level Mean ± SD ANOVA P CV 2-beat 4-beat 6-beat 2-beat 4-beat 6-beat Longitudinal strain (%) Basal -17.82 ± 4.83 -16.81 ± 4.48 -17.05 ± 3.56 0.402 34.5 34.9 31.5 Mid -16.34 ± 4.30 -14.91 ± 3.62 -14.46 ± 3.53 0.019 31.4 29.9 29.9 Apical -16.80 ± 4.33 -15.06 ± 3.12 -15.09 ± 3.02 0.008 30.6 28.5 24.9 Circumferential strain (%) Basal -12.93 ± 4.42 -14.16 ± 4.21 -13.05 ± 3.24 0.168 106.7 71.7 74.4 Mid -17.59 ± 3.86 -16.73 ± 3.56 -16.98 ± 3.51 0.406 43.0 36.9 30.3 Apical -22.14 ± 6.20 -19.04 ± 4.81 -20.32 ± 5.40 0.008 26.8 29.4 23.4 Abstract Figure 1

Conditions on the variable interpretation of |U| in Japanese

This paper examines the historical and phonological properties of h in Japanese. It shows that, by analysing a specific case of segmental variation, we not only deepen our understanding of the sound which varies but also shed light on some general characteristics of the sound system as a whole. Using an Element Theory approach (Anderson and Jones 1974; Kaye et al. 1985; Harris and Lindsey 1995; Scheer 1999; Nasukawa 2005; Cyran 2010; Backley 2011), the discussion focuses on the distribution of the element |U|, arguing that |U| is naturally weak in Japanese. This helps explain two idiosyncrasies in Japanese phonology – the restricted distribution of labial consonants and rounded vowels, and the patterning of h with labials. In modern Japanese, labiality is phonologically and phonetically weak. In vowels, u and w are produced without lip rounding, as unrounded [ɯ] and [ɰ]. And in consonants, the labial stop p is banned from certain contexts. These facts point to the inherent weakness of |U| in Japanese, where weakness refers to structural headedness; following Backley and Nasukawa (2009), it is assumed that labials are represented by headed |U| (cf. non-headed |U| in velars). To account for the restricted distribution of labials, it is argued that labiality (headed |U|) is only realised in Japanese if a specific structural condition is met: |U| must co-occur with (i.e. be supported by) another element from the same sub-group of ‘dark’ elements. Thus, the paper exploits the natural division between dark elements {|A|, |U|, |L|} and light elements {|I|, |H|, |Ɂ|}.

Modern Hebrew Sociophonetics

This paper surveys current research on the sociophonetics of Modern Hebrew, meaning the research of phonetic variation in Hebrew speech that is socially conditioned, or interpreted as socially meaningful. The paper discusses recent methodological and theoretical advances in sociophonetic research on production and perception, and illustrates how these have been implemented in Hebrew and influenced our understanding of Hebrew sociolinguistics. It further highlights a number of key sociolinguistic variables that have received the most attention in quantitative research on segmental variation: the pharyngeal segments (ħ) and (ʕ), the Hebrew rhotic (r), the glottal fricative (h), and the diphthong (ej). The paper concludes with a discussion of future directions and additional variables of interest which have the potential to advance the growing field of Hebrew sociophonetics.

Segmental Variation in a Duplicatedmsp2Pseudogene GeneratesAnaplasma marginaleAntigenic Variants

ABSTRACTAnaplasma marginaleis a prototypical highly antigenically variant bacterial pathogen dependent on the sequential generation of major surface protein 2 (Msp2) outer membrane variants to establish persistent infection. Msp2 is encoded by a single expression site, and diversity is achieved by gene conversion of chromosomally encodedmsp2pseudogenes. Analysis of the full complement ofmsp2pseudogenes in the St. Maries strain revealed identical sequences in different loci. The Florida strain shared the same locus structure, but in the loci where the St. Maries strain had two identical pseudogenes, the Florida strain had one whose sequence was identical to the St. Maries sequences, while the sequence of the second pseudogene differed. Consequently, we hypothesized that themsp2pseudogene repertoire arose via gene duplication, allowing structural variation to occur in one copy but the utility of the other to be retained. Using comparative genomics, we first established that duplication ofmsp2pseudogenes is common amongA. marginalestrains: all seven examined strains had at least one duplicate pair in which either the genes in the pair were maintained as identical copies or the genes contained segmental changes. We then demonstrated that a minimal segmental change in a duplicated pseudogene locus is sufficient for immune escape from the broad antibody response generated in a natural host, as is a completely divergent pseudogene sequence in an otherwise conserved locus. The results support a model in which a locus first duplicates, resulting in a second identical copy, and then progressively incorporates changes to generate anmsp2repertoire capable of generating sufficient antigenic variants to escape immunity and establish persistent infection.

Phonological reduction in maternal speech in northern Australian English: change over time

ABSTRACTSegmental variation in maternal speech to children changes over time. This study investigated variation in non-citation speech processes in a longitudinal, 26-hour corpus of maternal northern Australian English. Recordings were naturalistic parent–child interactions when children (N=4) were 1;6, 2;0, and 2;6. The mothers' speech was phonetically transcribed and analyzed. Based on previous sociophonetic research showing proportional changes in speech variants in maternal speech as children get older, it was predicted that deletion of word-initial /h/ and word-final /v/, processes common in non-citation speech, would increase over time. Instead results showed a non-linear change in deletion within a stable set of lexical items. Deletion proportionately increased between 1;6 and 2;0 and decreased between 2;0 and 2;6. Further analysis indicated increased deletion was not accounted for by changes in speech rate, which only marginally increased over time. Findings suggest mothers fine-tune differentially over time as children's receptive and productive language knowledge develops.