The leaf-area shrinkage effect can bias paleoclimate and ecology research.

PREMISE OF THE STUDY: Leaf area is a key trait that links plant form, function, and environment. Measures of leaf area can be biased because leaf area is often estimated from dried or fossilized specimens that have shrunk by an unknown amount. We tested the common assumption that this shrinkage is negligible. METHODS: We measured shrinkage by comparing dry and fresh leaf area in 3401 leaves of 380 temperate and tropical species and used phylogenetic and trait-based approaches to determine predictors of this shrinkage. We also tested the effects of rehydration and simulated fossilization on shrinkage in four species. KEY RESULTS: We found that dried leaves shrink in area by an average of 22% and a maximum of 82%. Shrinkage in dried leaves can be predicted by multiple morphological traits with a standard deviation of 7.8%. We also found that mud burial, a proxy for compression fossilization, caused negligible shrinkage, and that rehydration, a potential treatment of dried herbarium specimens, eliminated shrinkage. CONCLUSIONS: Our findings indicate that the amount of shrinkage is driven by variation in leaf area, leaf thickness, evergreenness, and woodiness and can be reversed by rehydration. The amount of shrinkage may also be a useful trait related to ecologically and physiological differences in drought tolerance and plant life history.

Craniometric and velopharyngeal assessment of infants with and without cleft palate.

BACKGROUND: The current study was designed to obtain qualitative and quantitative information of the velopharyngeal mechanism and craniometric dimensions in infants born with a normal mechanism and in infants with an unrepaired cleft palate. MATERIALS AND METHODS: Clinical magnetic resonance imaging data were obtained from the medical charts of 4 infants (2 with cleft lip and palate and 2 without) between the ages of 8 and 9 months. Craniometric measures and levator veli palatini muscle morphology were analyzed using visualization modeling software. Both raw measures and measures normalized by head circumference were examined. RESULTS: Patients 1 and 2 demonstrated normal velopharyngeal anatomy and a similar distance between levator muscle origins (38.9-40.7 mm), sagittal angles of origin (56-57 degrees), and levator muscle bundle lengths (28.4-30.7 mm). Patients with an unrepaired cleft palate displayed smaller oblique coronal angles of origins (58-62 degrees) compared with patients without cleft palate (62-67 degrees). Patients without cleft palate showed a steeper muscle (56-57 degrees) compared with patients without cleft palate (66-67 degrees). The basion-sella-nasion angle, hard palate length, and hard palate width measurements are related systematically to head circumference in this patient group. DISCUSSION: Results from the current study are in agreement with previous studies demonstrating variations across patients with cleft palate particularly in the muscle bundle lengths, distance between muscle origins, velar thickness, and velar length. Longitudinal studies are needed to determine how levator muscle and craniometric dimensions vary between those with and without cleft palate. A larger sample size is necessary to provide statistical analysis.

MRI and 3D Computer Modeling of the Levator Veli Palatini Muscle Before and After Primary Palatoplasty.

Abstract Objective: This study was designed for two purposes: (a) to obtain qualitative and quantitative information of the velopharyngeal mechanism in infants born with cleft palate before and after primary palatoplasty using MRI and 3D computer technology and (b) to demonstrate the potential of using computer technology and MRI for presurgical planning. Methods: Clinical MRI data were obtained from the medical charts of four infants (two with cleft lip and palate and two without) between 8 - 15 months of age. Computer technology was used to obtain quantitative measures of the levator veli palatini (levator) muscle and to create 3D computer models. Results: There was little difference in angles of origin between individuals with normal velopharyngeal anatomy (ranging from 41 masculine-45 masculine). Subjects with cleft palate displayed smaller angles of origins (average of 40 masculine) prior to surgery compared to that of the subjects without cleft palate (average of 43 masculine). Following surgery, the levator muscle increased in length (ranging from 32mm-40.4mm) and formed larger angles of origin (average of 39 masculine) becoming more similar to the angles of origin observed in the subjects without cleft palate. Conclusions: Although the subjects with normal anatomy displayed levator muscle lengths, thickness, and distance between origins that were dissimilar, nevertheless the angles of origin measures were similar. Subjects with cleft palate had greater variations in the angle of origin. It is possible that the angle of the muscle as it descends from the base of the skull might be a critical feature to produce velopharyngeal closure.