An exploratory study on the use of different composite magnetic and colour fingerprints in aeolian sediment provenance fingerprinting

Abstract Eight geochemical elements (Al, Ca, Fe, K, Na, Mg, Si, Ti) and 17 associated weathering indices were measured in 34 aeolian source samples and 10 sand dune target sediment samples in three absolute particulate size fractions. For each fraction, three final composite fingerprints (i.e., geochemical elements only, weathering indices only and a combination of the two) for discerning and ascribing the aeolian sediment sources were selected. The Modified MixSIR Bayesian un-mixing model was used to apportion aeolian source contributions using the final composite fingerprints. Regardless of the composite fingerprint used, all results across the different size fractions suggested that the south-eastern alluvial fan is the dominant (average contribution 50.6%, SD 19.0%) source of the sand dune samples, with the western alluvial fan being the second most important (average contribution 38.4%, SD 20.4%) source. Comparisons of the posterior distributions for the predicted source proportions generated using the nine composite fingerprints (three kinds of composite fingerprints*three particle size fractions) showed that the composite fingerprints combining the geochemical elements and weathering indices generated the most powerful source material discrimination. Our results demonstrate the use of weathering indices alongside more conventional elemental geochemistry tracers for investigations into sand dune sediment provenance.

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A hospital clerkship program for dental students: an exploratory study

Journal of Dental Education ◽

10.1002/j.0022-0337.1969.33.2.tb00173.x ◽

1969 ◽

Vol 33 (2) ◽

pp. 224-229

Author(s):

EA Stuebner ◽

RP Johnson

Keyword(s):

Exploratory Study ◽

Dental Students

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Classifying Disfluencies in Preschool- and School-Age Spanish–English Bilinguals Who Do Not Stutter: An Exploratory Study

Perspectives of the ASHA Special Interest Groups ◽

10.1044/2019_persp-19-00164 ◽

2020 ◽

Vol 5 (1) ◽

pp. 119-130

Author(s):

Raúl Rojas ◽

Farzan Irani

Keyword(s):

Exploratory Study ◽

Evidence Base ◽

Medium Effect ◽

Bilingual Children ◽

Linear Regression Models ◽

Cross Sectional ◽

Total Percentage ◽

Narrative Production ◽

Language Measures ◽

Mean Length Of Utterance

Purpose This exploratory study examined the language skills and the type and frequency of disfluencies in the spoken narrative production of Spanish–English bilingual children who do not stutter. Method A cross-sectional sample of 29 bilingual students (16 boys and 13 girls) enrolled in grades prekindergarten through Grade 4 produced a total of 58 narrative retell language samples in English and Spanish. Key outcome measures in each language included the percentage of normal (%ND) and stuttering-like (%SLD) disfluencies, percentage of words in mazes (%MzWds), number of total words, number of different words, and mean length of utterance in words. Results Cross-linguistic, pairwise comparisons revealed significant differences with medium effect sizes for %ND and %MzWds (both lower for English) as well as for number of different words (lower for Spanish). On average, the total percentage of mazed words was higher than 10% in both languages, a pattern driven primarily by %ND; %SLDs were below 1% in both languages. Multiple linear regression models for %ND and %SLD in each language indicated that %MzWds was the primary predictor across languages beyond other language measures and demographic variables. Conclusions The findings extend the evidence base with regard to the frequency and type of disfluencies that can be expected in bilingual children who do not stutter in grades prekindergarten to Grade 4. The data indicate that %MzWds and %ND can similarly index the normal disfluencies of bilingual children during narrative production. The potential clinical implications of the findings from this study are discussed.

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