Water vapour in the atmosphere of a transiting extrasolar planet

Water is predicted to be among the most abundant (if not the most abundant) molecular species after hydrogen in the atmospheres of close-in extrasolar giant planets ('hot Jupiters'). Several attempts have been made to detect water on such planets, but have either failed to find compelling evidence for it or led to claims that should be taken with caution. Here we report an analysis of recent observations of the hot Jupiter HD 189733b (ref. 6) taken during the transit, when the planet passed in front of its parent star. We find that absorption by water vapour is the most likely cause of the wavelength-dependent variations in the effective radius of the planet at the infrared wavelengths 3.6 mum, 5.8 mum (both ref. 7) and 8 mum (ref. 8). The larger effective radius observed at visible wavelengths may arise from either stellar variability or the presence of clouds/hazes. We explain the report of a non-detection of water on HD 189733b (ref. 4) as being a consequence of the nearly isothermal vertical profile of the planet's atmosphere.     

Invisible invasion: potential contamination of Yellowstone hot springs by human activity

This report establishes a baseline inventory of microorganisms in acidic hot springs of Yellowstone National Park (YNP). The analysis is based on observations carried out over the past 25 years using light microscopy, DNA staining, and electron microscopy of environmental samples. The inventory, while incomplete in that not all organisms have been cultured or examined using genetic approaches, represents a study of several solfatara (acid sulfate) geyser basins in YNP. We found that the types of microorganisms in flowing springs had changed over time. In contrast, no such changes occurred in mixing pools. We solicited opinions of prominent YNP microbiologists to address the issue of change in the context of human cross-contamination of springs and to suggest sampling protocols. While the consensus is that research has not introduced exotic species, this explanation is always uncertain. The issues related to this uncertainty, including human cross-contamination, are discussed, and sampling methods designed to best preserve the springs for future investigations are described.     

Vegetation change detection using artificial neural networks with ancillary data in Xishuangbanna,Yunnan Province,China

Timely and accurate change detection of the Earth’s surface features provides the foundation for better planning, management and environmental studies. In this study ANN change detection was used to perform vegetation change detection, and was compared with post-classification method. Before the post-classification was performed the ANN classification was used to yield multitemporal vegetation maps. ANN were also used to perform a one-pass classification for the images in 2003 and 2004. DEM and slope were used as two extra channels. During the training stage, the training data was separated into 82 subclasses including 36 change subclasses and 46 no change subclasses. Moreover NDVI differencing methods were used to develop the change mask. The result showed that combining the NDVI differencing method with visual interpretation when identifying reference areas can produce more accurate change detection results for the ANN one pass change classification. Moreover, it is effective to use elevation and slope as extra channels together with PCA components, to perform ANN-based change detection in mountainous study areas. It is also important to separate the vegetation transition classes into subclasses based on spectral response patterns, especially for mountainous terrains. This processing can reduce the topographic effect and improve the change detection accuracy.

     

Grass spider microhabitat use in Organ Pipe Cactus National Monument, Arizona

The grass spider ( Agelena naevia ), commonly found in Organ Pipe Cactus National Monument, Arizona, uses rodent burrows located under a shrub canopy more frequently for web construction than burrows located in the open. The average number of prey available in canopy microhabitat was greater than in open microhabitat, and unequal prey abundance may explain spider microhabitat use.        

A taxonomic investigation of variation withinCissus quadrangularis L. (Vitaceae) in Kenya

Using information from literature as well as records of localities on herbarium specimen labels at the East African Herbarium Nairobi (EA), materials ofCissus quadrangularis L.,C. cactiformis Gilg. andC. quinquangularis Chiov. were collected and new localities were sought. On the basis of the nature of their stem angles, the specimens ofC. quadrangularis were sorted into two variants, A and B. Variant A has smooth stem angles while variant B has rough stem angles. The authors have proposed that variant B should be recognized as a new variety withinC. quadrangularis. Variant A is the type variety ofC. quadrangularis. A map showing the distribution of the two variants in Kenya has been prepared. The rough-edged variant was found to be absent from the low-lying semi-arid regions of northern Kenya. The variants were found occurring in distinct, separate populations but without separate geographical patterns. The results of t-test show no significant difference (p=0.05) between the means of measurements of dimensions of various organs in the two variants. The stem angles of specimens of the two variants were studied under scanning electron microscope (SEM). This showed a clear morphological difference between the two variants. The results of the investigation support the hypothesis that the variation withinC. quadrangularis represents distinct kinds that can be recognized as taxa at infra-specific level. Foundation item: Supported by the China Ministry of Education Fund for University Staff Development in Key Subject Areas and Kenyatta University. Biography: Robert Wahiti. Gituru (1967-), male, Kenya, Ph. D. candidate, research direction: plant biosystematics.     

Editorial

This issue of Systemic Practice and Action Research focuses on systemic thinking in China. It results from considerable efforts invested in the project by Gerald Midgley and Jennifer Wilby. I am very grateful to Gerald and Jennifer, who have made available to our readership important research issues that would otherwise remain published only in the Chinese language. Inevitably a huge amount of editorial work is required when assisting people not fluent in the English language so that their papers are raised to a standard suitable for publication in a journal published in English. In addition, Gerald and Jennifer have put together a series of papers that make up an interesting whole that tells an important story. Thanks are extended to Gerald and Jennifer for this contribution.