Surrogacy tourism: the ethical and legal challenges

Although surrogacy seemed to have been practised since ancient times, its resurgence in the contemporary era has been nothing short of phenomenal. With advances made in reproductive technology, it is now possible to fertilise eggs and sperms in laboratories and have the embryo transferred into the womb of a surrogate mother for gestation. Through a combination of push and pull factors, this possibility of gestational surrogacy has led to the meteoric rise of cross-border surrogacy. This paper seeks to highlight the ethical and legal challenges associated with the practice, and calls for better legal oversight at international level

Spatiotemporal scaling of North American continental interior wetlands: implications for shorebird conservation

Within interior North America, erratic weather patterns and heterogeneous wetland complexes cause wide spatio-temporal variation in the resources available to migrating shorebirds. Identifying the pattern-generating components of landscape-level resources and the scales at which shorebirds respond to these patterns will better facilitate conservation efforts for these species. We constructed descriptive models that identified weather variables associated with creating the spatio-temporal patterns of shorebird habitat in ten landscapes in north-central Oklahoma. We developed a metric capable of measuring the dynamic composition and configuration of shorebird habitat in the region and used field data to empirically estimate the spatial scale at which shorebirds respond to the amount and configuration of habitat. Precipitation, temperature, solar radiation and wind speed best explained the incidence of wetland habitat, but relationships varied among wetland types. Shorebird occurrence patterns were best explained by habitat density estimates at a 1.5 km scale. This model correctly classified 86 % of shorebird observations. At this scale, when habitat density was low, shorebirds occurred in 5 % of surveyed habitat patches but occurrence reached 60 % when habitat density was high. Our results suggest scale dependence in the habitat-use patterns of migratory shorebirds. We discuss potential implications of our results and how integrating this information into conservation efforts may improve conservation strategies and management practices

Bayesian molecular clock dating of species divergences in the genomics era

It has been five decades since the proposal of the molecular clock hypothesis, which states that the rate of evolution at the molecular level is constant through time and among species. This hypothesis has become a powerful tool in evolutionary biology, making it possible to use molecular sequences to estimate the geological ages of species divergence events. With recent advances in Bayesian clock dating methodology and the explosive accumulation of genetic sequence data, molecular clock dating has found widespread applications, from tracking virus pandemics, to studying the macroevolutionary process of speciation and extinction, to estimating a timescale for Life on Earth

A review on substances and processes relevant for optical remote sensing of extremely turbid marine areas, with a focus on the Wadden Sea

The interpretation of optical remote sensing data of estuaries and tidal flat areas is hampered by optical complexity and often extreme turbidity. Extremely high concentrations of suspended matter, chlorophyll and dissolved organic matter, local differences, seasonal and tidal variations and resuspension are important factors influencing the optical properties in such areas. This review gives an overview of the processes in estuaries and tidal flat areas and the implications of these for remote sensing in such areas, using the Wadden Sea as a case study area. Results show that remote sensing research in extremely turbid estuaries and tidal areas is possible. However, this requires sensors with a large ground resolution, algorithms tuned for high concentrations of various substances and the local specific optical properties of these substances, a simultaneous detection of water colour and land-water boundaries, a very short time lag between acquisition of remote sensing and in situ data used for validation and sufficient geophysical and ecological knowledge of the area. © 2010 The Author(s)

Children and Their Parents: A Comparative Study of the Legal Position of Children with Regard to Their Intentional and Biological Parents in English and Dutch Law

This is a book about children and their parents. There are many different kinds of children and at least about as many different kinds of parents. In addition to the many different disciplines that study children and their parents, such as sociology, psychology, child studies and gender studies, to name but a few, this study concerns a legal question with regard to the parent-child relationship, namely how the law assigns parents to children. This subject is approached in a comparative legal perspective and covers England and The Netherlands. The book contains a detailed comparison and analysis of the manner in which the law in the two jurisdictions assigns the status of legal parent and/or attributes parental responsibility to the child’s biological and intentional parents. The concept ‘procreational responsibility’, which is introduced in the concluding chapter of the book, may be used as a tool to assess and reform existing regulations on legal parent-child relationships. The structure of the book, which is based on a categorisation of different family types in a ‘family tree’, enables the reader to have easy access to family-specific information.FdR – Publicaties zonder aanstelling Universiteit Leide