Modeling habitat suitability for chimpanzees (<Emphasis Type="Italic">Pan troglodytes verus</Emphasis>) in the Greater Nimba Landscape,Guinea, West Africa

Tropical forests and the biodiversity within them are rapidly declining in the face of increasing human populations. Resource management and conservation of endangered species requires an understanding of how species perceive and respond to their environments. Species distribution modeling (SDM) is an appropriate tool for identifying conservation areas of concern and importance. In this study, SDM was used to identify areas of suitable chimpanzee (Pan troglodytes verus) habitat within the Greater Nimba Landscape, Guinea, West Africa. This location was ideal for investigating the effects of landscape structure on habitat suitability due to the topographic variation of the landscape and the Critically Endangered status of the Western chimpanzee. Additionally, this is the only mountainous, long-term chimpanzee study site and little is known about the effects of topography on chimpanzee behavior. Suitable habitat was predicted based on the location of direct and indirect signs of chimpanzee presence and the spatial distribution of 12 biophysical variables within the study area. Model performance was assessed by examining the area under the curve. The overall predictive performance of the model was 0.721. The variables most influencing habitat suitability were the normalized difference vegetation index (37.8%), elevation (27.3%), hierarchical slope position (11.5%), surface brightness (6.6%), and distance to rivers (5.4%). The final model highlighted the isolation and fragmentation of chimpanzee habitat within the Greater Nimba Landscape. Understanding the factors influencing chimpanzee habitat suitability, specifically the biophysical variables considered in this study, will greatly contribute to conservation efforts by providing quantitative habitat information and improving survey efficiency.     

Mobile phones and children: Is precaution warranted?

Are there health related arguments to recommend that children limit their use of mobile telephones? The International Expert Group on Mobile Phones from the UK concluded so, but did not come up with convincing scientific data to back this statement. The Health Council of the Netherlands approached the problem by considering whether developmental arguments might be found, i.e., asking if there reason to believe that the heads of children are more susceptible to the electromagnetic fields emitted by mobile telephones than those of adults. It concluded that no major changes in head development occur after the second year of life that might point at a difference in electromagnetic susceptibility between children and adults. The Health Council therefore sees no reason to recommend limiting the use of mobile phones by children. Bioelectromagnetics 25:142–144, 2004. © 2004 Wiley‐Liss, Inc.     

Foetal liver infusion in a chronic myeloid leukemia patient with busulphan toxicity

A 36-year-old man suffering from chronic myeloid leukemia (in chronic phase) was initially treated with busulphan. At the end of 6 months of follow-up he developed bone marrow aplasia. He was given single foetal liver infusion therapy. The patient recovered fully from aplasia. He continued in chronic phase for more than 7 years with intermittent busulphan therapy.     

Incorporation of organic compounds into cell protein by lithotrophic,ammonia-oxidizing bacteria

Incorporation of organic compounds into cell protein by the obligate chemolithotrophs Nitrosomonas spec., Nitrosococcus oceanus, Nitrosococcus mobilis, Nitrosovibrio tenuis, Nitrosolobus spec., and Nitrosopira spec. was studied. In the presence of ammonia as energy source organic substrates were supplied. Distribution of ¹⁴C into cell amino acids arising from ¹⁴C-labelled glucose, Na-pyruvate, and Na-acetate was investigated. While carbon from glucose was distributed unrestricted, carbon from pyruvate preferably entered into the amino acids of the pyruvate and glutamate family and from acetate mainly into leucine and the glutamate family. Among the strains examined, slight differences were observed, but all should be included under group A of the scheme of Smith and Hoare (1977).     

Life history and the fitness consequences of imperfect information

The acquisition of information incurs costs in time, energy, exposure to predation, and/or lost opportunity. Without information, however, animals will be unable to assess the costs and benefits of decisions. Obtaining perfect information may be impossible, but how close to perfect do animals need assessments of ecological factors, such as predation risk, before estimation errors affect fitness? A recent article suggested that animals should be tolerant to imperfect information about predation risk, possibly relying on simple rules of thumb. Using a dynamic state variable approach, we examine some of the assumptions underlying this work, and show that tolerance towards imperfect information is dependent on life-history strategy. By changing the relationship between energy and fitness, assumptions about life-history strategies can be modified. Calculations show that tolerance to imperfect information is sensitive to these assumptions with some life histories leading to overestimation, while other life histories result in underestimation. One consistent effect across life histories is that animals with a higher rate of increase in fitness with respect to energy should show greater tolerance to imperfect information.