It is known that certain one-dimensional nearest-neighbor random walks in i.i.d. random space-time environments have diffusive scaling limits. Here, in the continuum limit, the random environment is represented by a `stochastic flow of kernels', which is a collection of random kernels that can be loosely interpreted as the transition probabilities of a Markov process in a random environment. The theory of stochastic flows of kernels was first developed by Le Jan and Raimond, who showed that each such flow is characterized by its -point motions. The authors' work focuses on a class of stochastic flows of kernels with Brownian -point motions which, after their inventors, will be called Howitt-Warren flows. The authors' main result gives a graphical construction of general Howitt-Warren flows, where the underlying random environment takes on the form of a suitably marked Brownian web. This extends earlier work of Howitt and Warren who showed that a special case, the so-called "erosion flow", can be constructed from two coupled "sticky Brownian webs". The authors' construction for general Howitt-Warren flows is based on a Poisson marking procedure developed by Newman, Ravishankar and Schertzer for the Brownian web. Alternatively, the authors show that a special subclass of the Howitt-Warren flows can be constructed as random flows of mass in a Brownian net, introduced by Sun and Swart. Using these constructions, the authors prove some new results for the Howitt-Warren flows.
The introduction of synthetic organic chemicals into the environment during the last few decades has given rise to major concern about the ecotoxicological effects and ultimate fate of these compounds. The pollutants that are considered to be most hazardous because of their intrinsic toxicity, high exposure level, or recalcitrant behavior in the environment have been placed on blacklists and other policy priority lists. The fate of synthetic compounds that enter the environment is mainly determined by their rate of biodegradation, which therefore also has a major effect on the degree of bioaccumulation and the risk of ecotoxicological effects. The degree and rate of biodegradation is also of critical importance for the feasibility of biological techniques to clean up contaminated sites and waste streams. The biodegradation of xenobiotics has thus been the subject of numerous studies, which resulted in thousands of publications in scientific journals, books, and conference proceedings. These studies led to a deeper understanding of the diversity of biodegradation processes. As a result, it has become possible to enhance the rate of degradation of recalcitrant pollutants during biological treatment and to design completely new treatment processes. At present, much work is being done to expand the range of pollutants to which biodegradation can be applied, and to make treatment techniques less expensive and better applicable for waste streams which are difficult to handle.
Mammals of Africa (MoA) is a series of six volumes which describes, in detail, every currently recognized species of African land mammal. This is the first time that such extensive coverage has ever been attempted, and the volumes incorporate the very latest information and detailed discussion of the morphology, distribution, biology and evolution (including reference to fossil and molecular data) of Africa's mammals. With 1,160 species and 16 orders, Africa has the greatest diversity and abundance of mammals in the world. The reasons for this and the mechanisms behind their evolution are given special attention in the series. Each volume follows the same format, with detailed profiles of every species and higher taxa. The series includes some 660 colour illustrations by Jonathan Kingdon and his many drawings highlight details of morphology and behaviour of the species concerned. Diagrams, schematic details and line drawings of skulls and jaws are by Jonathan Kingdon and Meredith Happold. Every species also includes a detailed distribution map. Extensive references alert readers to more detailed information. Volume I: Introductory Chapters and Afrotheria (352 pages) Volume II: Primates (560 pages) Volume III: Rodents, Hares and Rabbits (784 pages) Volume IV: Hedgehogs, Shrews and Bats (800 pages) Volume V: Carnivores, Pangolins, Equids and Rhinoceroses (560 pages) Volume VI: Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids (704 pages)
Thank you for visiting our website. Would you like to provide feedback on how we could improve your experience?
This site does not use any third party cookies with one exception — it uses cookies from Google to deliver its services and to analyze traffic.Learn More.