Modular diversification of the locomotor system in damselfishes (Pomacentridae)

As fish move and interact with their aquatic environment by swimming, small morphological variations of the locomotor system can have profound implications on fitness. Damselfishes (Pomacentridae) have inhabited coral reef ecosystems for more than 50 million years. As such, habitat preferences and behavior could significantly constrain the morphology and evolvability of the locomotor system. To test this hypothesis, we used phylogenetic comparative methods on morphometric, ecological and behavioral data. While body elongation represented the primary source of variation in the locomotor system of damselfishes, results also showed a diverse suite of morphological combinations between extreme morphologies. Results show clear associations between behavior, habitat preferences, and morphology, suggesting ecological constraints on shape diversification of the locomotor system. In addition, results indicate that the three modules of the locomotor system are weakly correlated, resulting in versatile and independent characters. These results suggest that Pomacentridae is shape may result from the interaction between (1) integrated parts of morphological variation that maintain overall swimming ability and (2) relatively independent parts of the morphology that facilitate adaptation and diversification. J. Morphol. 277:603–614, 2016. © 2016 Wiley Periodicals, Inc.     

Bayesian Wavelet Shrinkage of the Haar-Fisz Transformed Wavelet Periodogram

It is increasingly being realised that many real world time series are not stationary and exhibit evolving second-order autocovariance or spectral structure. This article introduces a Bayesian approach for modelling the evolving wavelet spectrum of a locally stationary wavelet time series. Our new method works by combining the advantages of a Haar-Fisz transformed spectrum with a simple, but powerful, Bayesian wavelet shrinkage method. Our new method produces excellent and stable spectral estimates and this is demonstrated via simulated data and on differenced infant electrocardiogram data. A major additional benefit of the Bayesian paradigm is that we obtain rigorous and useful credible intervals of the evolving spectral structure. We show how the Bayesian credible intervals provide extra insight into the infant electrocardiogram data.     

Measuring surgical decision-making with hypothetical cases

Hypothetical clinical cases were used to investigate surgical decision-making in relation to surgical rates across Ontario. Six procedures were studied (cholecystectomy, colectomy, inguinal herniorrhaphy, hysterectomy, cesarean section and tonsillectomy-adenoidectomy), and substantial differences of opinion regarding the choice of surgical or nonsurgical treatment were recorded. The decision to operate, however, was not made more frequently in Ontario counties with high operative rates, and none of the demographic variables studied were correlated with the decision to operate. Other variables that might have affected operative rates were not taken into account. There were also differences of opinion in referral decisions, but generally internists and pediatricians were less likely to refer the hypothetical cases to surgeons than were family physicians.     

Glycosphingolipids: 2H NMR study of the influence of ceramide fatty acid characteristics on the carbohydrate headgroup in phospholipid bilayers.

Galactosylceramides bearing a variety of different pure fatty acid chains were 2H labeled in the carbohydrate headgroup at C6 of the terminal galactose residue, for study by 2H NMR. Fatty acids investigated included the 24-carbon saturated lignoceric acid, 18-carbon saturated stearic acid, cis-9,10-unsaturated oleic acid, and D- and L-stereoisomers of alpha-hydroxystearic acid. Headgroup-deuterated glycolipids were incorporated at 10 mol % into unsonicated bilayers of 1-palmitoyl-2-oleoylphosphatidylcholine, and 2H NMR spectra were recorded at 65 and 40 degrees C. Under these experimental conditions, the membranes studied were primarily in the liquid-crystalline phase. At a given temperature, spectra for deuterated galactosylceramides dispersed in the fluid phase were remarkably similar, regardless of the nature of the fatty acid attached to the glycolipid sphingosine backbone. In each case, the spectrum consisted of a superposition of two quadrupolar powder patterns of approximately equal intensity. The spectra may be interpreted as arising from equal populations of two stereoisomers (pro-R and pro-S) of the deuterated galactose hydroxymethyl function, which is undergoing rapid (greater than 10(6) s-1) interconversion among the possible rotamers about the C5-C6 bond of the sugar ring. Within experimental error, the only fatty-acid-induced spectral difference detected among these glycosphingolipids deuterated in the carbohydrate headgroup was in the species with alpha-hydroxy-substituted fatty acids. At 65 degrees C, N-(D-alpha-hydroxy)stearoyl- and N-(L-alpha-hydroxy)stearoylgalactosylceramide gave rise to the same quadrupole splittings, but these differed marginally from the splittings observed for the other glycolipids studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Resolution of D- and L-galactose peracetates as their bis(ethyl L-lactate) acetals by gas-liquid chromatography

Reaction between ethyl L-lactate and each of a pair of sugar enantiomers, the peracetylated D-galactose and L-galactose diethyldithioacetals, produced two acyclic diasterioisomers. They could be separated by conventional gas-liquid chromatography. The corresponding fucose diastereomers were also separated. This process should make it possible to develop a general analytical method by which small amounts of enantiomeric sugars can be identified and their quantities measured.     

Morphological and histochemical studies on a PAS-positive granular leukocyte in blood and connective tissues of Catostomus commersonii Lacépède (teleostei:pisces).

This study was undertaken to identify an ubiquitous granular leukocyte found in Catostomus commersonni Lacépède. The cell contains large, numerous, strongly PAS-positive cytoplasmic granules, an eccentric nucleus and prominent, persistent juxtanuclear space. It develops in the hemopoietic tissue of the kidney, and mature cells are found not only in kidney and peripheral blood but also in areas of connective tissue where mast cells are usually located. Electron microscopy confirms the presence of a large Golgi apparatus, unlamellated cytoplasmic granules and extensive rough-surfaced endoplasmic reticulum. Histochemical studies show that the cytoplasmic granules are alcianophobic, non-metachromatic and unstained by acridine orange. Histamine is detectable spectrophotometrically in kidney tissue, but the PAS-positive granular leukocyte does not consistently degranulate after treatment with histamine liberator 48/80. The authors suggest that while the PAS-positive granular leukocyte is not identical with classical basophils/mast cells, which are absent in C. commersonnii, it may represent an evolutionary precursor of these cells.     

Passive muscle mechanical properties of the medial gastrocnemius in young adults with spastic cerebral palsy

Individuals with spastic cerebral palsy (SCP) exhibit restricted joint range of motion and increased joint stiffness due to structural alterations of their muscles. Little is known about which muscle–tendon structures are responsible for these alterations. The aim of this study was to compare the passive mechanics of the ankle joint and medial gastrocnemius (MG) muscle in young adults with SCP and typically developed (TD) individuals. Nine ambulant SCP (17±2 years) and ten TD individuals (18±2 years) participated in the study. Physiological cross sectional area was estimated using freehand 3D ultrasound and found to be 37% lower in the SCP group. An isokinetic dynamometer rotated the ankle through its range while joint torque and ultrasound images of the MG muscle fascicles were simultaneously measured. Mean ankle stiffness was found to be 51% higher and mean MG fascicle strain 47% lower in the SCP group. Increased resistance to passive ankle dorsiflexion in SCP appears to be related to the inability of MG muscle fascicles to elongate with increased force.