Site fidelity and homing behaviour of intertidal sculpins revisited.

To assess the repeatability of an ecological study, this study both partially replicates and extends a previous study on the site fidelity and homing ability of two abundant and ecologically important species of rocky intertidal sculpin fishes, Oligocottus maculosus and Oligocottus snyderi. A traditional mark and recapture approach was utilized and found that both of these species display high site fidelity to a home range of tidepools and homing ability to these pools, confirming the findings of previous work. Unlike the previous study, however, there was no effect of body size on homing ability and a modelling approach that incorporates encounter probability provided evidence for a sex effect on homing ability. In addition, this study extends the maximum homing ability of O. snyderi to 179 m and O. maculosus to 218 m, which were the maximum displacement distances for each species in this study, suggesting they may be capable of even greater homing distances. This work, however, finds that homing success was negatively related to displacement distance. These findings suggest adult sculpin populations are likely to be highly sub-structured geographically, possibly contributing to the exceptionally high species richness of the group.

Can AFLP genome scans detect small islands of differentiation? The case of shell sculpture variation in the periwinkle Echinolittorina hawaiiensis.

Genome scans have identified candidate regions of the genome undergoing selection in a wide variety of organisms, yet have rarely been applied to broadly dispersing marine organisms experiencing divergent selection pressures, where high recombination rates can reduce the extent of linkage disequilibrium (LD) and the ability to detect genomic regions under selection. The broadly dispersing periwinkle Echinolittorina hawaiiensis exhibits a heritable shell sculpture polymorphism that is correlated with environmental variation. To elucidate the genetic basis of phenotypic variation, a genome scan using over 1000 AFLP loci was conducted on smooth and sculptured snails from divergent habitats at four replicate sites. Approximately 5% of loci were identified as outliers with Dfdist, whereas no outliers were identified by BayeScan. Closer examination of the Dfdist outliers supported the conclusion that these loci were false positives. These results highlight the importance of controlling for Type I error using multiple outlier detection approaches, multitest corrections and replicate population comparisons. Assuming shell phenotypes have a genetic basis, our failure to detect outliers suggests that the life history of the target species needs to be considered when designing a genome scan.

Effect of maternal hydration on fetal renal pyelectasis.

OBJECTIVE: To assess the effect of maternal hydration on fetal pyelectasis. METHODS: Thirteen pregnant women with fetal pyelectasis and 13 controls matched for gestational age were recruited during the same period. Ultrasound and Doppler studies and maternal urine specific gravity measurements were carried out before and after maternal oral hydration. The data were analyzed by either a two- or three-factor analysis of variance. RESULTS: Renal artery Doppler pulsatility index was significantly greater in the study group than in the controls (2.37 versus 1.83; P=.009) and this finding was unaffected by maternal hydration status. After hydration, the maternal urinary specific gravity decreased significantly (1.018 versus 1.009; P < .001), the amniotic fluid index (AFI) increased significantly (14.27 versus 18.24 cm; P < .001), and the fetal renal pelvis diameter increased significantly (0.29 versus 0.46 cm; P=.002) in both the study and control groups. Renal pelvis anteroposterior diameter after hydration did not differ significantly whether the fetal bladder was full or empty (0.7 versus 0.6 cm; P=.1). In this study, each subject served as her own control (ie, from before to after hydration). Three of 13 controls met the diagnostic criteria for pyelectasis after maternal hydration. CONCLUSION: The AFI increases after maternal hydration in both normal fetuses and those with pyelectasis. The fetal renal pelvis anteroposterior diameter increases with maternal hydration in both normal fetuses and those with pyelectasis and is independent of the state of the fetal bladder. The renal artery Doppler pulsatility index is significantly greater in fetuses with pyelectasis than in controls.

Operationally defined apoplastic and symplastic aluminum fractions in root tips of aluminum-intoxicated wheat.

Knowledge of the mechanistic basis of differential aluminum (Al) tolerance depends, in part, on an improved ability to quantify Al located in the apoplastic and symplastic compartments of the root apex. Using root tips excised from seedlings of an Al-tolerant wheat cultivar (Triticum aestivum L. cv Yecora Rojo) grown in Al solutions for 2 d, we established an operationally defined apoplastic Al fraction determined with six sequential 30-min washes using 5 mm CaCl(2) (pH 4.3). Soluble symplastic Al was eluted by freezing root tips to rupture cell membranes and performing four additional 30-min CaCl(2) washes, and a residual fraction was determined via digestion of root tips with HNO(3). The three fractions were then determined in Yecora Rojo and a sensitive wheat cultivar (Tyler) grown at 18, 55, or 140 mum total solution Al (Al(T)). When grown at equal Al(T), Tyler contained more Al than Yecora Rojo in all fractions, but both total Al and fractional distribution were similar in the two cultivars grown at Al(T) levels effecting a 50% reduction in root growth. Residual Al was consistently 50 to 70% of the total, and its location was elucidated by staining root tips with the fluorophore morin and examining them using fluorescence and confocal laser scanning microscopy. Wall-associated Al was only observed in tips prior to any washing, and the residual fraction was manifested as distinct staining of the cytoplasm and nucleus but not of the apoplastic space. Accordingly, the residual fraction was allocated to the symplastic compartment for both cultivars, and recalculated apoplastic Al was consistently approximately 30 to 40% of the total. Distributions of Al in the two cultivars did not support a symplastic detoxification hypothesis, but the role of cytoplasmic exclusion remains unsettled.

Reproductive counselling for adolescent females with phenylketonuria.

It is our goal to provide young adolescents with the information needed to make an informed choice, and a support system for them and their families, in whatever they choose. 1. Sterilization is not advocated. 2. Pregnancy is not advocated. 3. Reliable birth control methods are encouraged. 4. Organized reproductive counseling is essential using concrete problem solving--diagram, taste tests, etc. 5. Diet trial before or during pregnancy requires an informed understanding of the responsibilities of parenthood.