Nonlinear transmission and colour-centre dynamics in germanosilicate fibres at 420-540 nm

We report evidence in support of the view that induced loss and non-linear transmission in pure germanosilicate fibers at blue/green wavelengths are governed by the formation (via two-photon absorption), spontaneous and stimulated transformation and bleaching (via single-photon events) of Ge(1), Ge(2) and Ge(3) colour-centres. Using a tunable pulsed dye laser, the excitation spectrum of the induced absorption, its spectral attenuation and the effects of germania concentration and thermal annealing are investigated

Linkage analysis in a large kindred with autosomal dominant transmission of polyglandular autoimmune disease type II (Schmidt syndrome)

Schmidt syndrome (PGA syndrome type II) is a rare condition characterized by polyglandular failure. It is an autosomal dominant trait with variable expressivity that was inherited over four generations in an Indiana kindred. Association of HLA-B8 has been reported with Schmidt syndrome. Our proband is a 12-year-old boy with Addison disease, insulin dependent diabetes mellitus (IDDM), and vitiligo. Two of his eight sibs had either IDDM (sister) or vitiligo and hyperthyroidism (brother). His mother had hypothyroidism. Seven members of earlier generations apparently were also affected. We obtained peripheral blood for HLA and genetic analysis from 21 relatives in a family with 8 Schmidt syndrome individuals in three generations. HLA studies on 15 affected and unaffected relatives showed only 2 of 7 persons with B8-containing haplotypes. Therefore, no association exists between the B8-containing haplotype and the syndrome. We identified informative marker loci. No evidence for linkage of the Schmidt locus to any of the 14 markers was found and close linkage to esterase D and adenylate kinase and possibly properdin factor B was excluded

Hepatic effects of tartrazine (E 102) after systemic exposure are independent of oestrogen receptor interactions in the mouse

Tartrazine is a food colour that activates the transcriptional function of the human oestrogen receptor alpha in an in vitro cell model. Since oestrogens are cholestatic, we hypothesised tartrazine will cause periportal injury to the liver in vivo. To test this hypothesis, tartrazine was initially administered systemically to mice resulting in a periportal recruitment of inflammatory cells, increased serum alkaline phosphatase activity and mild periportal fibrosis. To determine whether an oestrogenic effect may be a key event in this response, tartrazine, sulphonated metabolites and a food additive contaminant were screened for their ability to interact with murine oestrogen receptors. In all cases, there were no interactions as agonists or antagonists and further, no oestrogenicity was observed with tartrazine in an in vivo uterine growth assay. To examine the relevance of the hepatic effects of tartrazine to its use as a food additive, tartrazine was orally administered to transgenic NF-κB-Luc mice. Pre- and concurrent oral treatment with alcohol was incorporated given its potential to promote gut permeability and hepatic inflammation. Tartrazine alone induced NF- κB activities in the colon and liver but there was no periportal recruitment of inflammatory cells or fibrosis. Tartrazine, its sulphonated metabolites and the contaminant inhibited sulphotransferase activities in murine hepatic S9 extracts. Given the role of sulfotransferases in bile acid excretion, the initiating event giving rise to periportal inflammation and subsequent hepatic pathology through systemic tartrazine exposure is therefore potentially associated an inhibition of bile acid sulphation and excretion and not on oestrogen receptor-mediated transcriptional function. However, these effects were restricted to systemic exposures to tartrazine and did not occur to any significant effect after oral exposure

Estimating Soil Moisture Depletion from Climate, Crop and Soil Data

TREMENDOUS international scientific effort has been expended on evaporation and transpiration problems during the past decade as evidenced by hundreds of technical publications, and numerous conferences. However, use of this scientific achievement by agriculturalists, project planners and operators of irrigation farms has lagged behind technological advancements. The lag in adaptation of new technology by the user can be partly attributed to a lack of time, technical training and experience in meteorology, physics and agronom

Changes in Climate and Potential Evapotranspiration Across a Large Irrigated Area in Idaho

Ground level climatic measurements were taken along a 50 km transect going from dry sagebrush land into the center of a large irrigated area in southern Idaho. Measurements in May, when the desert area was dry, indicated that climatic changes across the transect were minimal. In August, when the desert was obviously very dry, air temperatures decreased, vapor pressure increased, and windspeed was reduced about 40 percent within the irrigated area. The results demonstrate that any weather service agency or group must consider the distance from dry surroundings when selecting sites that are to be representative of climatic conditions over irrigated fields

Urban groundwater quality in sub-Saharan Africa: current status and implications for water security and public health

Groundwater resources are important sources of drinking water in Africa, and they are hugely important in sustaining urban livelihoods and supporting a diverse range of commercial and agricultural activities. Groundwater has an important role in improving health in sub-Saharan Africa (SSA). An estimated 250 million people (40% of the total) live in urban centres across SSA. SSA has experienced a rapid expansion in urban populations since the 1950s, with increased population densities as well as expanding geographical coverage. Estimates suggest that the urban population in SSA will double between 2000 and 2030. The quality status of shallow urban groundwater resources is often very poor due to inadequate waste management and source protection, and poses a significant health risk to users, while deeper borehole sources often provide an important source of good quality drinking water. Given the growth in future demand from this finite resource, as well as potential changes in future climate in this region, a detailed understanding of both water quantity and quality is required to use this resource sustainably. This paper provides a comprehensive assessment of the water quality status, both microbial and chemical, of urban groundwater in SSA across a range of hydrogeological terrains and different groundwater point types. Lower storage basement terrains, which underlie a significant proportion of urban centres in SSA, are particularly vulnerable to contamination. The relationship between mean nitrate concentration and intrinsic aquifer pollution risk is assessed for urban centres across SSA. Current knowledge gaps are identified and future research needs highlighted

Solar sail capture trajectories at Mercury

Mercury is an ideal environment for future planetary exploration by solar sail since it has proved difficult to reach with conventional propulsion and hence remains largely unexplored. In addition, its proximity to the Sun provides a solar sail acceleration of order ten times the sail characteristic acceleration at 1 AU. Conventional capture techniques are shown to be unsuitable for solar sails and a new method is presented. It is shown that capture is bound by upper and lower limits on the orbital elements of the approach orbit and that failure to be within limits results in a catastrophic collision with the planet. These limits are presented for a range of capture inclinations and sail characteristic accelerations. It is found that sail hyperbolic excess velocity is a critical parameter during capture at Mercury, with only a narrow allowed band in order to avoid collision with the planet. The new capture methodis demonstrated for a Mercury sample return mission

Urban groundwater quality in sub-Saharan Africa: current status and implications for water security and public health

Groundwater resources are important sources of drinking water in Africa, and they are hugely important in sustaining urban livelihoods and supporting a diverse range of commercial and agricultural activities. Groundwater has an important role in improving health in sub-Saharan Africa (SSA). An estimated 250 million people (40% of the total) live in urban centres across SSA. SSA has experienced a rapid expansion in urban populations since the 1950s, with increased population densities as well as expanding geographical coverage. Estimates suggest that the urban population in SSA will double between 2000 and 2030. The quality status of shallow urban groundwater resources is often very poor due to inadequate waste management and source protection, and poses a significant health risk to users, while deeper borehole sources often provide an important source of good quality drinking water. Given the growth in future demand from this finite resource, as well as potential changes in future climate in this region, a detailed understanding of both water quantity and quality is required to use this resource sustainably. This paper provides a comprehensive assessment of the water quality status, both microbial and chemical, of urban groundwater in SSA across a range of hydrogeological terrains and different groundwater point types. Lower storage basement terrains, which underlie a significant proportion of urban centres in SSA, are particularly vulnerable to contamination. The relationship between mean nitrate concentration and intrinsic aquifer pollution risk is assessed for urban centres across SSA. Current knowledge gaps are identified and future research needs highlighted

Breastfeeding modifies the impact of diarrhoeal disease on relative weight: a longitudinal analysis of 2–12 month-old Filipino infants

Undernutrition and diarrhoeal disease are major causes of infant mortality. We investigated the combined roles of breastfeeding and diarrhoea on infant size in 2940 infants from the Cebu Longitudinal Health and Nutrition Survey. The study aimed to assess whether breastfeeding status modified the deficits associated with diarrhoeal disease. The primary exposures were combinations of current breastfeeding status (yes/no), the presence of diarrhoeal disease in previous week (yes/no) and a categorical survey variable (six surveys taken at bimonthly intervals when infants were 2–12 months of age). Relative weight (weight-for-length z-scores), calculated using the WHO growth standards, was estimated using sex-stratified, fixed-effects longitudinal models that also adjusted for energy from complementary foods. Post-estimation Wald tests were conducted to identify subgroup differences in relative weight. Diarrhoea was associated with reduced relative weight in both breastfed and non-breastfed infants of 6–12 months. Diarrhoea-related deficits in relative weight were significantly exacerbated in non-breastfed girls of 6 and 8 months. Importantly, in infants <6 months, being breastfed and having diarrhoea was still associated with greater relative weight compared with being non-breastfed and diarrhoea-free. Breastfeeding emerged as a strong contributor to relative weight in younger infants (<6 months) while diarrhoeal disease strongly contributed to deficits in relative weight in older infants (6–12 months). These findings underscore the importance of breastfeeding for promoting infant nutritional status in infants with or without diarrhoea from birth to 12 months

ISO Spectroscopy of Young Stellar Objects

Observations of gas-phase and solid-state species toward young stellar objects (YSOs) with the spectrometers on board the Infrared Space Observatory are reviewed. The excitation and abundances of the atoms and molecules are sensitive to the changing physical conditions during star-formation. In the cold outer envelopes around YSOs, interstellar ices contain a significant fraction of the heavy element abundances, in particular oxygen. Different ice phases can be distinguished, and evidence is found for heating and segregation of the ices in more evolved objects. The inner warm envelopes around YSOs are probed through absorption and emission of gas-phase molecules, including CO, CO_2, CH_4 and H_2O. An overview of the wealth of observations on gas-phase H_2O in star-forming regions is presented. Gas/solid ratios are determined, which provide information on the importance of gas-grain chemistry and high temperature gas-phase reactions. The line ratios of molecules such as H_2, CO and H_2O are powerful probes to constrain the physical parameters of the gas. Together with atomic and ionic lines such as [0 I] 63 µm, [S I] 25 µm and (Si II] 35 µm, they can also be used to distinguish between photon- and shock-heated gas. Finally, spectroscopic data on circumstellar disks around young stars are mentioned. The results are discussed in the context of the physical and chemical evolution of YSOs