Novel methods for discriminating behavioral differences between stickleback individuals and populations in a laboratory shoaling assay

Threespine sticklebacks (Gasterosteus aculeatus) from different habitats have been observed to differ in shoaling behavior, both in the wild and in laboratory studies. In the present study, we surveyed the shoaling behavior of sticklebacks from a variety of marine, lake, and stream habitats throughout the Pacific Northwest. We tested the shoaling tendencies of 113 wild-caught sticklebacks from 13 populations using a laboratory assay that was based on other published shoaling assays in sticklebacks. Using traditional behavioral measures for this assay, such as time spent shoaling and mean position in the tank, we were unable to find population differences in shoaling behavior. However, simple plotting techniques revealed differences in spatial distributions during the assay. When we collapsed individual trials into population-level data sets and applied information theoretic measurements, we found significant behavioral differences between populations. For example, entropy estimates confirm that populations display differences in the extent of clustering at various tank positions. Using log-likelihood analysis, we show that these population-level observations reflect consistent differences in individual behavioral patterns that can be difficult to discriminate using standard measures. The analytical techniques we describe may help improve the detection of potential behavioral differences between fish groups in future studies.     

Parental mosaic trisomy 21 detected following maternal cell contamination of an amniotic fluid specimen from a normal male pregnancy

We report a case of maternal mosaic trisomy 21 ascertained at prenatal diagnosis as a result of maternal cell contamination of an amniotic fluid sample. A 34 year old female was referred for karyotyping because of a previous trisomy 21 pregnancy. Chromosome analysis of primary in situ cultures showed a karyotype of 47,XX, + 21[6]/46,XY[32]/46,XX[2]. Molecular testing demonstrated maternal cell contamination of the amniotic fluid sample and G-banded karyotyping of maternal blood showed that 3/200 cells had trisomy 21, consistent with the mother being a Down syndrome mosaic. A normal male baby with a 46,XY chromosome complement was delivered at 30 weeks. This case emphasises the need for close collaboration between cytogenetic and molecular genetics laboratories in resolving unusual cases of mosaicism. Copyright © 2007 John Wiley & Sons, Ltd.     

A risk framework for preventing salinity

Salinity is an insidious soil conservation issue. Its expression can be greatly removed in time and space from its causes, so a focus on prevention is preferred. To avoid over or under-investment, a communication strategy for salinity needs to be a staged approach, the risks defined and the assets at risk identified.

This paper describes a risk assessment schema and associated information base designed to support community investment in preventative actions. It describes a new approach to salinity risk similar to the concepts of diagnosis and staging used by physicians for diseases such as cancer. It outlines the diagnostic tools now being developed to define the timeframes of salinity development, the biophysical features of the landscape within which salinity develops and the riskiness of current and alternative management systems and matches this with a complementary community process designed to build knowledge and intervention. A GIS/database system captures the concepts of salinity risk and a large array of diagnostic information in a form designed for the development of salinity knowledge in the community and to guide investment in salinity prevention. The communication strategy and the salinity risk system are being applied in the Fitzroy Basin, Australia, an area of approximately 150,000 km² straddling the Tropic of Capricorn.     

Prenatal diagnosis of del(11)(p13p15)

Prenatal diagnosis of del(11)(p13p15) was made on cultured amniotic fluid cells and confirmed on fetal skin fibroblasts after termination of pregnancy. Both irides appeared behind schedule in development by 2–3 weeks in reference to the gestational age of the fetus. It is suggested that the aniridia of the aniridia-Wilms tumour association is due to developmental arrest. Confirmation of this complex is difficult at mid-gestation without critical pathological study of the eyes.     

Degradation of littoral habitats by residential development: woody debris in lakes of the Pacific Northwest and Midwest, United States

One of the least understood aspects of aquatic ecology is the role of riparian zones of lakes, and how these habitats and their functions are impacted by human development of lakeshores. We investigated the effects of residential lakeshore development on littoral coarse woody debris (CWD) distribution and on riparian forest characteristics by comparing 18 lakes in the U.S. Pacific Northwest with 16 previously surveyed lakes in the U.S. Upper Midwest. Residential development had a strong negative effect on CWD and riparian forest characteristics at both local and whole-lake scales. There was a strong positive correlation between riparian forest density and littoral CWD abundance in both regions. We found regional variation in CWD and riparian forest characteristics, mostly owing to differences in native forests. Our results suggest the role of local processes in determining CWD distribution and point to potential regional differences in littoral habitat structure associated with forest composition and lakeshore development that may have consequences for littoral-pelagic coupling in lakes.     

Prenatal findings on ultrasound and X-ray in a case of overgrowth syndrome associated with increased nuchal translucency

A case of prenatal diagnosis of an overgrowth syndrome at 30 weeks of gestation is reported. The diagnosis was suggested on the basis of increased fetal growth from 16 weeks onwards, advanced bone age, and characteristic facial features such as hypertelorism, broad forehead and small chin. The fetus presented at 12 weeks with a markedly increased nuchal translucency thickness and generalized skin edema, but normal karyotype. Serial ultrasound scans revealed brain abnormalities including mild unilateral ventriculomegaly and a cyst in the cavum septi pellucidi. The pregnancy was terminated at the parents' request at 32 weeks of gestation and postmortem examination confirmed the prenatal findings. This case demonstrates the possibility of prenatal diagnosis of early overgrowth syndromes and highlights the dilemma arising from the prenatal diagnosis of a non-lethal condition associated with an uncertain prognosis and poorly documented in utero. Copyright © 2001 John Wiley & Sons, Ltd.