The NAO troposphere–stratosphere connection

Using monthly mean data, daily data, and theoretical arguments, relationships between surface pressure variations associated with the North Atlantic Oscillation (NAO), tropopause height, and the strength of the stratospheric vortex are established. An increase in the NAO index leads to a stronger stratospheric vortex, about 4 days later, as a result of increased equatorward refraction of upward-propagating Rossby waves. At tropopause level the effects of the enhanced NAO index and stratospheric polar vortex are opposite, resulting in a lower tropopause over Iceland and a higher tropopause over the Arctic. The raising of the Arctic tropopause leads to a stretching and spinup of the tropospheric column and is therefore associated with a lowering of the surface pressure near the North Pole. For monthly mean data it is found that a standard deviation increase in the NAO index is associated with a 10% increase in the strength of the stratospheric vortex, as measured by potential vorticity at 500 K. A simple theoretical model predicts that this is associated with about 300-m elevation of the Arctic tropopause, as is observed, and a 5-hPa lowering of the surface pressure at the North Pole. The effects of the spinup of the tropospheric column may project on the NAO pattern so that the stratosphere acts as an integrator of the NAO index.

Protection of live bacteria from bile acid toxicity using bile acid adsorbing resins

We previously demonstrated that a dry, room temperature stable formulation of a live bacterial vaccine was highly susceptible to bile, and suggested that this will lead to significant loss of viability of any live bacterial formulation released into the intestine using an enteric coating or capsule. We found that bile and acid tolerance is very rapidly recovered after rehydration with buffer or water, raising the possibility that rehydration in the absence of bile prior to release into the intestine might solve the problem of bile toxicity to dried cells. We describe here a novel formulation that combines extensively studied bile acid adsorbent resins with the dried bacteria, to temporarily adsorb bile acids and allow rehydration and recovery of bile resistance of bacteria in the intestine before release. Tablets containing the bile acid adsorbent cholestyramine release 250-fold more live bacteria when dissolved in a bile solution, compared to control tablets without cholestyramine or with a control resin that does not bind bile acids. We propose that a simple enteric coated oral dosage form containing bile acid adsorbent resins will allow improved live bacterial delivery to the intestine via the oral route, a major step towards room temperature stable, easily administered and distributed vaccine pills and other bacterial therapeutics

'A load too heavy': Critical reflections on the child labor problem in Africa's small-scale mining sector

This paper provides an extended analysis of the child labor problem in the artisanal and small-scale mining (ASM) sector, focusing specifically on the situation in sub-Saharan Africa. In recent years, the issue of child labor in ASM has garnered significant attention from the International Labor Organization (ILO), which has been particularly active in raising public awareness of the problem; and, has proceeded to implement policies and collaborative project work aimed at Curtailing children's participation in ASM activities in a number of African countries. The analysis concludes with a critical appraisal of an ILO project recently launched in the Talensi-Nabdam District in the Upper East Region of Ghana, which sheds light on how the child labor problem is being tackled in practice in ASM communities in sub-Saharan Africa. (c) 2008 Elsevier Ltd. All rights reserved.

Output risk aspects of genetically modified crop technology in South Africa

Technology involving genetic modification of crops has the potential to make a contribution to rural poverty reduction in many developing countries. Thus far, insecticide-producing 'Bt' varieties of cotton have been the main GM crops under cultivation in developing nations. Several studies have evaluated the farm-level performance of Bt varieties in comparison to conventional ones by estimating production technology, and have mostly found Bt technology to be very successful in raising output and/or reducing insecticide input. However, the production risk properties of this technology have not been studied, although they are likely to be important to risk-averse smallholders. This study investigates the output risk aspects of Bt technology using a three-year farm-level dataset on smallholder cotton production in Makhathini flats, Kwa-Zulu Natal, South Africa. Stochastic dominance and stochastic production function estimation methods are used to examine the risk properties of the two technologies. Results indicate that Bt technology increases output risk by being most effective when crop growth conditions are good, but being less effective when conditions are less favourable. However, in spite of its risk increasing effect, the mean output performance of Bt cotton is good enough to make it preferable to conventional technology even for risk-averse smallholders.

Production risk, pesticide use and GM crop technology in South Africa

Technology involving genetic modification of crops has the potential to make a contribution to rural poverty reduction in many developing countries. Thus far, pesticide-producing Bacillus thuringensis (Bt) varieties of cotton have been the main GM crops under cultivation in developing nations. Several studies have evaluated the farm-level performance of Bt varieties in comparison to conventional ones by estimating production technology, and have mostly found Bt technology to be very successful in raising output and/or reducing pesticide input. However, the production risk properties of this technology have not been studied, although they are likely to be important to risk-averse smallholders. This study investigates the output risk aspects of Bt technology by estimating two 'flexible risk' production function models allowing technology to independently affect the mean and higher moments of output. The first is the popular Just-Pope model and the second is a more general 'damage control' flexible risk model. The models are applied to cross-sectional data on South African smallholders, some of whom used Bt varieties. The results show no evidence that a 'risk-reduction' claim can be made for Bt technology. Indeed, there is some evidence to support the notion that the technology increases output risk, implying that simple (expected) profit computations used in past evaluations may overstate true benefits.

Evidence for an inhibitory role of bone morphogenetic protein(s) in the follicular-luteal transition in cattle

Bone morphogenetic proteins (BMPs) and their receptors are expressed in ovarian theca cells (TC) and granulosa cells (GC) and BMPs have been implicated in the regulation of several aspects of follicle development including thecal androgen production and granulosal oestrogen production. Their potential involvement in luteal function has received less attention. in this study, we first compared relative abundance of mRNA transcripts for BMPs, activin-beta A and BMP/activin receptors in bovine corpus luteum (CL) and follicular theca and granulosa layers before undertaking functional in vitro experiments to test the effect of selected ligands (BMP6 and activin A) on luteinizing bovine TC and GC. Relative to P-actin transcript abundance, CL tissue contained more BMP4 and -6 mRNA than granulosa, more BMP2 mRNA than theca but much less activin-beta A mRNA than both granulosa and theca. Transcripts for all seven BMP/activin receptors were readily detected in each tissue and two transcripts (BMPRII, ActRIIA) were more abundant in CL than either theca or granulosa, consistent with tissue responsiveness. In vitro luteinization of TC and GC from antral follicles (4-6 mm) was achieved by culturing with 5% serum for 6 days. Treatment with BMP6 (0, 2, 10, and 50 ng/ml) and activin A (0, 2, 10 and 50 ng/ml) under these conditions dose-dependently suppressed forskolin-induced progesterone (P-4) secretion from both cell types without affecting cell number. BMP6 reduced forskolin-stimulated upregulation of STAR mRNA and raised 'basal' CYP17A1 mRNA level in theca-lutein cells without affecting expression of CYP11A1 or hydroxy-Delta-5-steroid dehydrogenase, 3 beta- and steroid Delta-isomerase 1 (HSD3B1). In granulosa-lutein cells, STAR transcript abundance was not affected by BMP6, whereas forskolin-induced expression of CYP11A1, HSD3B1, CYP19A1 and oxytocin transcripts was reduced. In both cell types, follistatin attenuated the suppressive effect of activin A and BMP6 on forskolin-induced P4 secretion but had no effect alone. Granulosa-lutein cells secreted low levels of endogenous activin A (similar to 1 ng/ml); BMP6 reduced this, while raising follistatin secretion thus decreasing activin A:follistatin ratio. Collectively, these findings support inhibitory roles for BMP/activin signalling in luteinization and steroidogenesis in both TC and GC.

An unusual choanoflagellate protein released by hedgehog autocatalytic processing

Hedgehog proteins are important cell-cell signalling proteins utilized during the development of multicellular animals. Members of the hedgehog gene family have not been detected outside the Metazoa, raising unanswered questions about their evolutionary origin. Here we report a highly unusual hedgehog-related gene from a choanoflagellate, a close unicellular relative of the animals. The deduced C-terminal domain, Hoglet-C, is homologous to the autocatalytic domain of Hedgehog proteins and is predicted to function in autocatalytic cleavage of the precursor peptide. In contrast, the N-terminal Hoglet-N peptide has no similarity to the signalling peptide of Hedgehog (Hh-N). Instead, Hoglet-N is deduced to be a secreted protein with an enormous threonine-rich domain of unprecedented size and purity (over 200 threonine residues) and two polysaccharide-binding domains. Structural modelling reveals that these domains have a novel combination of features found in cellulose-binding domains (CBD) of types IIa and IIb, and are expected to bind cellulose. We propose that the two CBD domains enable Hoglet-N to bind to plant matter, tethering an amorphous nucleophilic anchor, facilitating transient adhesion of the choanoflagellate cell. Since HhC and Hoglet-C are homologous, but Hh-N and Hoglet-N are not, we argue that metazoan hedgehog genes evolved by fusion of two distinct genes.

Architect and user interaction: The spoken representation of form and functional meaning

The paper is an investigation of the exchange of ideas and information between an architect and building users in the early stages of the building design process before the design brief or any drawings have been produced. The purpose of the research is to gain insight into the type of information users exchange with architects in early design conversations and to better understand the influence the format of design interactions and interactional behaviours have on the exchange of information. We report an empirical study of pre-briefing conversations in which the overwhelming majority of the exchanges were about the functional or structural attributes of space, discussion that touched on the phenomenological, perceptual and the symbolic meanings of space were rare. We explore the contextual features of meetings and the conversational strategies taken by the architect to prompt the users for information and the influence these had on the information provided. Recommendations are made on the format and structure of pre-briefing conversations and on designers' strategies for raising the level of information provided by the user beyond the functional or structural attributes of space.

Responsiveness to change by standard-form contract drafters: A case study of the FIDIC White Book

Purpose – The purpose of this paper is to focus on the Fédération Internationale des Ingénieurs-Conseils (FIDIC) White Book standard form of building contract. It tracks the changes to this contract over its four editions, and seeks to identify their underlying causes. Design/methodology/approach – The changes made to the White Book are quantified using a specific type of quantitative content analysis. The amended clauses are then examined to understand the nature of the changes made. Findings – The length of the contract increased by 34 per cent between 1990 and 2006. A large proportion of the overall increase can be attributed to the clauses dealing with “conflict of interest/corruption” and “dispute resolution”. In both instances, the FIDIC drafting committees have responded to international developments to discourage corruption, and to encourage the use of alternative dispute resolution. Between 1998 and 2006, the average length of the sentences increased slightly, raising the question of whether long sentences are easily understood by users of contracts. Research limitations/implications – Quantification of text appears to be particularly useful for the analysis of documents which are regularly updated because changes can be clearly identified and the length of sentences can be determined, leading to conclusions about the readability of the text. However, caution is needed because changes of great relevance can be made to contract clauses without actually affecting their length. Practical implications – The paper will be instructive for contract drafters and informative for users of FIDIC's White Book. Originality/value – Quantifying text has been rarely used regarding standard-form contracts in the field of construction.

When school is not enough: new initiatives in intergenerational language transmission in Wales

This paper examines language reproduction in the family in the context of a highly innovative project in Wales, where the Welsh language has been in decline for over a century. Although Welsh-medium schooling has played a pivotal role in slowing and even reversing language shift in recent decades, there is mounting evidence of the dangers of over-reliance on education. The Twf (Growth) Project was established in 2002 with funding from the National Assembly for Wales with the aim of raising awareness of the benefits of bilingualism among parents and prospective parents. Analysis of interviews with the main stakeholders in the project (managers, the Twf project officers, parents, health workers and a range of other partners), publicity materials and observations of project staff at work suggests that the achievements of the project lie in two main areas: the recognition of the need for building strong alliances with professional groups and organisations that work with families with young children; and the development of a marketing strategy appropriate for the target audience. It is argued that the experience of the project will be of interest to those addressing the issue of intergenerational transmission in a range of other minority language settings.

Language transmission in the family in Wales: an example of innovative language planning.

This paper examines the achievements to date of Twf (“Growth”) — a project initiated as part of language planning efforts in Wales to encourage families to bring up their children to be bilingual. Evidence is presented of the ways in which the project has succeeded in raising awareness of the advantages of bilingualism amongst parents, prospective parents and the public at large by working strategically with health professionals and Early Years organizations, and by developing a range of highly innovative promotional materials. Given the central importance of the family as a site of intergenerational language transmission, the achievements of this project are likely to be of interest to those concerned with language planning in other minority communities in many other parts of the world. The lessons for language planning both in Wales and in other settings are discussed.

In-service training needs in an African context: a study of headteacher and teacher perspectives in the Gucha District of Kenya

Improving the quality of teaching is an educational priority in Kenya, as in many developing countries. The present paper considers various aspects of in-service education, including views on the effectiveness of in-service, teacher and headteacher priorities in determining in-service needs and the constraints on providing in-service courses. These issues are examined though an empirical study of 30 secondary headteachers and 109 teachers in a district of Kenya. The results show a strong felt need for in-service provision together with a firm belief in the efficacy of in-service in raising pupil achievement. Headteachers had a stronger belief in the need for in-service for their teachers than did the teachers themselves. The priorities of both headteachers and teachers were dominated by the external pressures of the schools, in particular the pressures for curriculum innovation and examination success. The resource constraints on supporting attendance at in-service courses were the major problems facing headteachers. The results reflect the difficulties that responding to an externally driven in-service agenda creates in a context of scarce resources.

Apolipoprotein B-48: comparison of fasting concentrations measured in normolipidaemic individuals using SDS-PAGE, immunoblotting and ELISA

Raised levels of chylomicrons and chylomicron remnants, which circulate following a meal, have been implicated in the development of atherosclerosis. Apolipoprotein (apo) B-48 is exclusively associated with chylomicron particles and provides a specific direct measurement of the number of intestinally derived lipoproteins in the circulation. The quantification of apo B-48 in biological samples is difficult due to the very low concentration in plasma, structural similarity to the N-terminal 48% of apo B-100 and lack of an appropriate standard for apo B-48. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), followed by coomassie blue staining, has been used for many years to measure apo B-48 levels in triacylglycerol (TAG)-rich lipoprotein samples. The raising of antiserum to apo B-48 has led to development of more sensitive and specific methods including immunoblotting and enzyme-linked immunosorbant assays (ELISAs). This has enabled direct measurement of apo B-48 in plasma without the need for separation into TAG-rich lipoproteins. A high degree of variability was observed in the apo B-48 concentrations reported in the literature both within and between the SDS-PAGE, immunoblotting and ELISA methods. (C) 2004 Elsevier Ireland Ltd. All rights reserved.

Affective prosody in children with Williams syndrome

The aim of the current study was to investigate expressive affect in children with Williams syndrome ( WS) in comparison to typically developing children in an experimental task and in spontaneous speech. Fourteen children with WS, 14 typically developing children matched to the WS group for receptive language ( LA) and 15 typically developing children matched to the WS groups for chronological age ( CA) were recruited. Affect was investigated using an experimental Output Affect task from the Profiling Elements of Prosodic Systems-Child version ( PEPS-C) battery, and by measuring pitch range and vowel durations from a spontaneous speech task. The children were also rated for level of emotional involvement by phonetically naive listeners. The WS group performed similarly to the LA and CA groups on the Output Affect task. With regard to vowel durations, the WS group was no different from the LA group; however both the WS and the LA groups were found to use significantly longer vowels than the CA group. The WS group differed significantly from both control groups on their range of pitch range and was perceived as being significantly more emotionally involved than the two control groups.