A simple method for preparing prometaphase chromosomes from amniotic fluid cell cultures

A simple method for preparing prometaphase chromosomes from amniotic fluid cell cultures is described. The technique is based upon several key steps including: (1) reduced colcemid concentration, (2) reduced exposure to trypsin-EDTA, and (3) maintaining cells in single suspension by adjusting cell concentration appropriately. Chromosomes with banding resolution up ot 800 bands per haploid set can be routinely produced. The described methodology is particularly useful in defining and establishing the clinical significance of subtle structural aberrations.     

Behaviour of the institute of oceanographic science's rectangular midwater trawls: Theoretical aspects and experimental observations

The behaviour of two rectangular midwater trawls, the RMT 1+8 and the RMT 1+8M, is described. The RMT 1+8 consists of a pair of rectangular nets contained within the same frame-a small mouth area RMT 1 of mesh size 320 m and a larger RMT 8 of mesh size 4.5 mm. The RMT 1+8M is a multiple version of the RMT 1+8, combining three RMT 1s and three RMT 8s within the same frame. An expression is developed to describe the dependence of mouth angle on speed for the RMT 1+8 when towed horizontally. Theoretical estimates of the changes in mouth angle with speed agree well with experimental observations. Within normal towing speeds the RMT 1+8 is sensitive to changes in speed; this sensitivity is especially marked in the RMT 1. Between speeds of about 2.6 and 8.0 knots the RMT 8 does not alter its mouth angle with changes in speed; this behaviour is not shown by the RMT 1—at least within a practical speed range. The performance of the RMT 1+8M cannot be completely described by the theory developed for the RMT 1+8 and possible explanations for this are discussed. The multiple net is considerably less sensitive to changes in towing speed; all three nets of each type have similar mouth angles at a constant speed. Variations in warp load with speed for both trawls are described.     

Improving Predictive Models of In‐Stream Phosphorus Concentration Based on Nationally‐Available Spatial Data Coverages

Spatial data are playing an increasingly important role in watershed science and management. Large investments have been made by government agencies to provide nationally‐available spatial databases; however, their relevance and suitability for local watershed applications is largely unscrutinized. We investigated how goodness of fit and predictive accuracy of total phosphorus (TP) concentration models developed from nationally‐available spatial data could be improved by including local watershed‐specific data in the East Fork of the Little Miami River, Ohio, a 1,290 km² watershed. We also determined whether a spatial stream network (SSN) modeling approach improved on multiple linear regression (nonspatial) models. Goodness of fit and predictive accuracy were highest for the SSN model that included local covariates, and lowest for the nonspatial model developed from national data. Septic systems and point source TP loads were significant covariates in the local models. These local data not only improved the models but enabled a more explicit interpretation of the processes affecting TP concentrations than more generic national covariates. The results suggest SSN modeling greatly improves prediction and should be applied when using national covariates. Including local covariates further increases the accuracy of TP predictions throughout the studied watershed; such variables should be included in future national databases, particularly the locations of septic systems.     

Deliberative public participation and hexachlorobenzene stockpiles

This paper is concerned with the quality of citizen involvement in relation to the governance of industrial risks. Specifically, it explores the hexachlorobenzene (HCB) case relative to best practice public participation, which is consistent with deliberative democratic theory. The case could be judged a public participation failure given that the community committee in combination with the corporate sponsor was unable to agree on a mutually acceptable technological pathway. This stalemate might have been attributable in part to the time spent on the task of review. A diligent participation working party could have created a much more effective public participation plan, grounded in the core values of professional public participation practice.     

Analysis of composite sampling data using the principle of maximum entropy

A new tool is presented based on the principle of maximum entropy for enhanced hot spot detection based on composite sampling with no (or minimal) requirement for composite breakdown. The methodology presented here is easy to implement and facilitates the use of multiple criteria for evaluating attainment of site remediation objectives. The new methodology provides very simple decision rules that can easily be used by non-statisticians and complements the use of composites for control of residual mean concentrations.     

The relative influence of habitat loss and fragmentation: do tropical mammals meet the temperate paradigm?

The relative influence of habitat loss vs. habitat fragmentation per se (the breaking apart of habitat) on species distribution and abundance is a topic of debate. Although some theoretical studies predict a strong negative effect of fragmentation, consensus from empirical studies is that habitat fragmentation has weak effects compared with habitat loss and that these effects are as likely to be positive as negative. However, few empirical investigations of this issue have been conducted on tropical or wide-ranging species that may be strongly influenced by changes in patch size and edge that occur with increasing fragmentation. We tested the relative influence of habitat loss and fragmentation by examining occupancy of forest patches by 20 mid- and large-sized Neotropical mammal species in a fragmented landscape of northern Guatemala. We related patch occupancy of mammals to measures of habitat loss and fragmentation and compared the influence of these two factors while controlling for patch-level variables. Species responded strongly to both fragmentation and loss, and response to fragmentation generally was negative. Our findings support previous assumptions that conservation of large mammals in the tropics will require conservation strategies that go beyond prevention of habitat loss to also consider forest cohesion or other aspects of landscape configuration.     

SAFE—The Special Non-invasive Advances in Fetal and Neonatal Evaluation Network: aims and achievements

In this short review, the objectives and work of SAFE—the Special Non-invasive Advances in Fetal and Neonatal Evaluation Network, a European Union Framework VI network of excellence is described. We demonstrate how this network facilitates the implementation of non-invasive prenatal diagnosis (NIPD) for single gene disorders, fetal rhesus typing, aneuploidy and pregnancy complications. Copyright © 2008 John Wiley & Sons, Ltd.