Light and clomazone effects on tobacco (Nicotiana tabacum) callus and leaf discs

The effects of clomazone on the growth of tobacco (Nicotiana tabacum L. 'NC2326') callus and leaf discs were studied under four light regimes. Callus cultures and leaf discs were grown on Murashige and Skoog medium supplemented with IAA and kinetin. Light regimes were: dark grown callus kept in the dark and also transferred to the light; light grown callus kept in the light and also transferred to the dark. Two-month-old callus (cultured for 2 months from initiation) grew more rapidly than twelve-month-old callus (cultured for 12 months from initiation) under all conditions tested. Callus transferred from light to dark, or from dark to light, increased in fresh weight slower than did the callus maintained totally in light or dark. Clomazone (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone) at 140 mg l(-1) or more was lethal to both callus and leaf discs whereas 10 mg l(-1) was stimulatory to growth. Callus tissue responded to clomazone differently depending on the light regime under which it was grown. While clomazone may be affecting the isoprenoid pathway in the callus and leaf disks resulting in growth inhibition, it is possible that other target sites are also being affected and contribute to the reduced growth.     

Characterisation of airborne particles collected within and proximal to an opencast coalmine: South Wales,U.K

Airborne particulate matter has been collected from within,and proximal to, an opencast coal mine in south Wales. Thiswork forms the first part of a three year project to collectand characterise, then determine the possible toxicology ofairborne particles in the south Wales region. High-resolutionField Emission SEM has shown that the coal mine dusts consistlargely of an assemblage of mineral grains and vehicle exhaustparticles. SEM-EDX has shown that the mineralogical make-up ofthe PM10 is complex, heterogeneous, and constantly changing.These findings are supported by analytical TEM-EPXMA.However, patterns can be determined relating the mineralogicalcomposition of the airborne particles to collection locationsand mining activities within the opencast. At our studyopencast, Park Slip West, quartz, which has known healtheffects, never exceeded 30% of the total collection mass, andaverage levels were much less. Vehicle exhaust emissions wasthe largest source in terms of particle numbers. The mass ofairborne particulate matter within the pit averagedapproximately twice that of outside the pit: importantlyhowever, this higher mass was due to relatively large, andnon-respirable, mineral grains. This study demonstrates that the physicochemical andmineralogical characterisation of airborne particles frommining and quarrying is essential to quantify the respirablefraction, and to identify potentially hazardous componentswithin the PM10.     

Fire and explosion assessment on oil and gas floating production storage offloading (FPSO): An effective screening and comparison tool

Fires and explosions have been identified as major potential hazards for Oil and Gas Floating Production Storage Offloading (FPSO) installations and pose risk to personnel, assets, and the environment. Current fire and explosion assessment (FEA) tools require physical effect modeling software and follows standards from API, ISO, and engineering practices. However, the tools are not specific to any particular system such as an FPSO, and do not provide comprehensive guidance for safety engineers to perform FEA.This paper discusses the development of a screening and comparison tool for FEA on FPSOs and the incorporation of an expert system into the tool. The results are computerized using MS Excel/VBA to provide a structured and comprehensive assessment on each equipment and module handling natural gas, crude oil, methanol and diesel on FPSO topsides.This tool features built-in calculations for jet and pool fire size estimation for gas/liquid releases, and the ability to perform Quantitative Risk Analysis (QRA) to specify the personnel and equipment risk for varying leak sizes and process conditions. Control and recovery measures are incorporated as an expert system based on report findings, engineering practices, and relevant standards. Bowtie analysis is applied in the tool to define detailed control and recovery measures for the FPSO based on the incident scenarios. An explosion assessment is performed by incorporating physical effect modeling software results.Unique features provided in the tool include fire and radiation contour mapping on an FPSO layout to help determine personnel and equipment risk more accurately and fire pump sizing that can be used to verify the amount of water deluge system required to mitigate fires and explosions. In addition, flexibility of data input (process data, failure rate data, etc.) and user interfaces assist safety engineers to screen and compare process alternatives, check design quality, and evaluate design options at any design stage.     

A methodology to establish the morphology of ambient aerosols

The morphology of ambient particulate matter (PM) is an important characteristic that seldom is measured and reported. A study was performed to determine the viability of a method to establish the distribution of shapes and the fractal dimensions of aggregates of ambient aerosols. Particles of PM with aerodynamic diameter less than or equal to 2.5 microm (PM2.5) were captured on different days via size-independent electrostatic precipitation at two sites in St. Louis and examined in a scanning electron microscope (SEM). Nonvolatile particles between 0.1 and 2.5 microm were readily identified via SEM. Particle shapes were classified as fibrous, spherical, agglomerated, or "other." A computer program using the nested-squares algorithm was developed and used to determine the fractal dimensions of the aggregates. More particles were collected at the St. Louis-Midwest Supersite on June 14, 2002, than were collected on the Washington University campus loading dock on May 31, 2002, but the campus samples had a higher percentage of aggregates. On one day of sampling at the Supersite, the aggregate fraction was highest in the morning (14.3% between 7:00 and 9:00 a.m.) and steadily declined during the day (1.3% between 5:00 and 7:00 p.m.). The fractal dimensions of the aerosols were 1.65 in the morning (7:00-9:00 a.m.), decreased to 1.49 (11:00 a.m.-1:00 p.m.), and then increased to 1.87 (5:00-7:00 p.m.). The results show that the fractal dimension is not a static value and that ambient aerosols are not perfectly spherical.     

Statistical modelling of water colour in the uplands: The Upper Midd catchment 1979-1987

The increasing colour of raw water from the uplands is a matter of concern to water managers. The colour record for the period 1979-1987 is examined for the catchment of Upper Nidderdale, North Yorkshire. The variation in colour shows a marked seasonality with peaks occurring during the autumn months. No long-term sustained increase in colour is found, although colour levels were high in 1980, 1985 and 1987. Colour is found to be highly correlated with iron and, more particularly, aluminium. There is no relationship between colour and turbidity which suggests that there is no direct link between colour levels and erosion on the catchments. Colour increases appear to relate to large soil moisture deficits in months immediately prior to the colour flush and to high soil moisture deficits in the previous year. Complementary relationships are found between monthly rainfall totals and colour. In the light of these findings, it is suggested that high colour is associated with water table lowering and aerobic decomposition of the upper organic peat layers.     

Uptake and depuration of 131I by the edible periwinkle Littorina littorea: uptake from seawater

Uptake and depuration experiments for the edible periwinkle Littorina littorea have been performed using 131I-labelled seawater. Throughout the experimental phase the winkles were fed on unlabelled Chondrus crispus. 131I concentrations in winkles during uptake followed linear first-order kinetics with an uptake half-time of 11 days, whereas for depuration a triphasic sequence with biological half-lives of 4, 23 and 56 days was determined. In general, iodine turnover in winkles via labelled seawater appears to be slower than observed for other molluscs (2-3 days). Most of the activity prior to and after depuration is found to be in the shell, with indications that shell and soft parts accumulate and depurate 131I at a similar rate. The operculum displays the highest specific activity of all fractions with a concentration factor of 750 l kg(-1). Concentration factors for whole winkle, shell, soft parts and digestive gland are in the order of 40-60 l kg(-1), higher than the IAEA recommended CF value for iodine in molluscs of 10 l kg(-1). The 131I CF in winkles is closer to that of the conservative radionuclides 99Tc and 137Cs than the CF of the particle reactive radionuclides (239,240)Pu and 241Am.     

Comparison between the predictions of a Gaussian plume model and a Lagrangian particle dispersion model for annual average calculations of long-range dispersion of radionuclides

This study attempts to validate the applicability of a simple Gaussian dispersion model for predicting long-range dispersion of continuous releases from an industrial site, by comparison with a Lagrangian particle dispersion model. The United Kingdom Meteorological Office model NAME has been used to predict annual average concentrations of radionuclides over Western Europe, resulting from discharges from the British Nuclear Fuels (BNFL) site at Sellafield, UK. The results are compared here to calculations performed using a conventional Gaussian type of dispersion model, PLUME. The results of the Gaussian model were compared at 14 locations within Western Europe at long range (up to 1700 km). The differences in predictions between the models were explained readily by differences in the way dispersion and deposition processes are represented in the two models. However, differences are generally small compared to the expected precision of the models. The implementation of environmental processes in NAME is more complete and realistic than in PLUME, and as such the results from this model may be considered more realistic. However, given that PLUME is much simpler to use, and appears to over-estimate, rather than under-estimate, environmental concentrations, its use for radiological assessments appears appropriate.     

Saltcedar control and water salvage on the Pecos river, Texas, 1999–2003

A large scale ecosystem restoration program was initiated in 1997 on the Pecos River in Western Texas. Saltcedar (Tamarix spp.), a non-native invasive tree, had created a near monoculture along the banks of the river by replacing most native vegetation. Local irrigation districts, private landowners, federal and state agencies, and private industry worked together to formulate and implement a restoration plan, with a goal of reducing the effects of saltcedar and restoring the native ecosystem of the river. An initial management phase utilizing state-of-the-art aerial application of herbicide began in 1999 and continued through 2003. Initial mortality of saltcedar averaged about 85–90%. Monitoring efforts were initiated at the onset of the project to include evaluating the effects of saltcedar control on salinity of the river water, efficiency of water delivery down the river as an irrigation water source, and estimates of water salvage. To date, no effect on salinity can be measured and irrigation delivery was suspended in 2002–2003 due to drought conditions. Water salvage estimates show a significant reduction in system water loss after saltcedar treatment. However, a flow increase in the river is not yet evident. Monitoring efforts will continue in subsequent years.     

A longitudinal study of age-specific reproductive output and body condition among male rhesus macaques,<Emphasis Type="Italic"> Macaca mulatta</Emphasis>

In many mammalian species, male reproductive success appears to climb sharply at young adulthood, form a brief plateau during prime ages, and decline among older animals, a pattern often attributed to reduced physical condition with ageing. However, solid evidence to either substantiate or refute this profile among nonhuman primates is lacking. Here, we combine a decade of genetic analysis of paternity among free-ranging rhesus macaques, Macaca mulatta, with information about body condition in order to evaluate how changes in morphology might govern age-specific reproduction among males. We show that age-specific reproductive success traverses the same life history profile as found in other mammals, but reductions in reproductive output with advanced age were associated with reduced chances of survivorship rather than accompanied by diminished body condition. We demonstrate that variance in male age at onset of reproduction is three times greater than variance in female age at onset of reproduction. We provide the first evidence from primates that age-specific reproductive output among males is not a consequence of age-related changes in body condition, but reflects social and demographic factors.     

上海市城区典型道路行驶特征研究

对上海市城区快速干道、主干道和次于道等3种典型道路上的机动车行驶特征和交通状况进行试验和调查，得出了上海市城区各类道路上机动车行驶特征参数和交通密度。结果显示，上海市城区各类道路综合行驶特征为平均速度低，加减速频繁。其中又以主干道交通状况最差。文中的数据和结论不仅可以用于上海城市交通规划，而且对控制道路两旁机动车污染具有重要意义。