Some previous work on arthropod development is insufficiently detailed or incompletely reported. Much of the published information in this area is of limited use for the general analysis of life cycles. These difficulties arise primarily because many experiments do not control fully for the strain of the material (and even its specific identity) nor for rearing conditions, do not adequately take account of the complexity of life cycles and their stages, or are restricted to only part of the life cycle. For example, 285such factors as variable numbers of instars, sexual differences, abbreviated or hidden stages and dormancies may mean that the "average durations" reported apply to an unknown mixture of developmental types. Nor are experiments always designed or results reported and analysed in a logical and transparent manner. Undefined terms may obscure what actual developmental intervals were measured. Highly derived developmental or demographic measures may obscure core data. Statistical information may be inadequate. Such pitfalls are reviewed here, suggesting ways to ensure that results on the duration of development are both valid for specific studies and more widely useful. General experimental difficulties, recommended background information that should be provided, recommended life-cycle intervals and their terminology, and recommended ways to report numerical and statistical information are briefly summarized in tabular form.
This program enables the user to visualize f0 contours, to plot vowels in the F1/F2 space for multiple points in the vowel interval, e.g. at 20%, 50% and 80%, and to visualize vowel durations.
(The tool is implemented in R. We used the following packages: phonR, gplots, plotrix, lattice, readxl, WriteXLS, DT,
psych and pracma. We thank the developers of these packages.)
German has various homophonous sibilant fricatives of phonemic or morphemic nature that can appear in word-final position. In English, the functional status of a word-final \s\ influences its durational properties, with phonemic \s\ being longer than morphemic types. The data set presented here is a small selection of laboratory-elicited German sentences containing various words with final sibilant phonemes (e.g., "das Haus") and morphemes (plural, genitive, clitic, inflection). Durations of the \s\ types were measured and compared across the conditions. An ANOVA between the \s\ types and post-hoc Tukey pair-wise comparisons are presented that show various significant differences.
The submission consists of a csv data file, containing a number of variables, and a PDF document detailing the experiment and variables.