Effects of air temperature on seed growth and maturation in cowpea (Vigna unguiculata)

This investigation has attempted to quantify the effects of air temperature on seedgrowth in cowpea independent of phenology and other major ontogenetic changes inthe physiology of the parent plant. Fruits produced in identical positions on the mainstem of plants (which, in three of the four environments tested, were almost identicalin dry weight and morphology at the onset of flowering) were harvested at regularintervals after anthesis. Four day-night temperature regimes (mean values inparentheses) were investigated: 33-24 C (283 C); 33-19 C (256 C); 27-24 C (254 C) and 27-19 C (228 C). Overall, the mean dry weight ofindividual seeds contained in the first fruit produced in the coolest regime was morethan double that recorded in the warmest environment, with the two intermediateregimes giving intermediate but similar results to each other. These final weightswere brought about by almost identical durations of the linear phase of increase indry weight (about 9 days) in the three warmer regimes but a longer duration (about 11 days) in the coolest regime, while the rates of increase in dry weight during thisphase were identical in the three cooler regimes (about 13 mg seed^-1 day^-1) butconsiderably less in the warmest environment (about 10 mg seed^-1 day^-1). Attributes of the first formed fruits are compared with ‘average’ fruits in eachenvironment and implications of these data in legume physiology and breeding are discussed.     

A roundtable on responsible innovation with autologous stem cells in Australia,Japan and Singapore

We report on a roundtable event hosted in Singapore that sought to identify some of the ethical and regulatory challenges in translating autologous cell-based interventions, particularly those claiming to involve stem cells, into safe and effective therapies and to propose some solutions to encourage responsible innovation with these products. Challenges are identified in the three areas of cell manufacturing and processing, innovative uses of autologous cells in clinical practice and standards of evidence. Proposed solutions are discussed within a co-operative model of statutory laws and regulations that can enable product development with autologous cells and professional codes and standards that can encourage ethical conduct in clinical practice. Future research should be directed toward establishing regional networks for the development of internationally consistent standards in manufacturing and ethical codes of conduct for innovating with stem cells, and other autologous cells, and fostering ongoing exchange between jurisdictions.     

An aquatic ecotone and its significance in conservation

Aquatic invertebrates were sampled throughout an area of transition between a well-established reservoir and a perennial stream in the KwaZulu-Natal Midlands of South Africa. The visibly obvious separation of stream and reservoir was not reflected by the invertebrates. Communities overlapped in species, ranging from fast-flowing stream and moderate-flowing stream, through a transitional ecotone, which ran along the exposed reservoir edge and stream edges, to sheltered edges of reservoir and stream then to open reservoir. These features reflected the degree of water movement (whether from waves or riffles) and type of substratum, rather than visibly lotic or lentic conditions. The main aquatic ecotone between the open reservoir and the main stream was therefore not at the mouth of the stream but along the edges of both systems. The centre of the reservoir and centre of the stream, although physically connected, were quite different in their invertebrates and were separate patches with a sharp boundary. They were faunistically connected through the communities of the edge ecotone. The ecotone acted like a semi- permeable membrane to the drifting stream fauna with movement back again apparently mostly in the air, suggesting a patchy metapopulation model. Both the river continuum and boundary concepts were applicable to this multi-system. The ecotone did not show any edge effect and accords more with the variegation than fragmentation model. The great difference in patterns of pelagic, littoral and terrestrial communities has important implications for zoning of water bodies for different conservation and recreation activities.     

Morphological and genetic differentiation between populations of river crabs (Decapoda: Potamonautidae) from the Western Gape, South Africa, with a taxonomic re-examination of Gecarcinautes brincki

As part of a larger study on the systematics of river crabs of the family Potamonautidae in southern Africa, several populations of potamonautid crabs were collected from the Cape Peninsula and surrounds, Western Cape. Two species were represented: Gecarcinautes brincki and Potamonautes perlatus. The structure of the mandibular palp in the eight populations of G. brincki examined was variable, and in four populations, the structure of this palp was the same as that which can be found in species of Potamonautes. This paper re-examines the taxonomic status of G. brincki , quantifies the morphological and genetic differentiation between populations of G. brincki and P. perlatus from the Cape Peninsula, and determines the extent of morphological and genetic differentiation among geographically separated populations of G. brincki. Examination of type and other material confirmed that Gecarcinautes brincki conforms to the current diagnosis of the genus Potamonautes (family Potamonautidae) to which it is therefore transferred. Discriminant functions analysis and protein gel electrophoresis showed that P. perlatus and P. brincki are morphometrically and genetically distinct, with the three P. perlatus populations separating from the six P. brincki populations at a genetic identity value of I = 0.66 (D = 0.419). The results also showed that P. brincki is a highly structured entity, with die populations collected from the Cape Peninsula clearly separating both genetically (I = 0.75, corresponding to D = 0.296), and morphologically (presence or absence of a flange on the terminal segment of the mandibular palp) from those collected further east. The lack of gene flow between populations of this species is discussed in the light of current species concepts.     

Violence in War and Peace: An Anthology

Violence in War and Peace: An Anthology . Nancy Scheper-Hughes and Philippe Bourgois, eds. Malden, MA: Blackwell Publishers, 2004. 496 pp.