Physicochemical characterization of particulate emissions from a compression ignition engine employing two injection technologies and three fuels.

Alternative fuels and injection technologies are a necessary component of particulate emission reduction strategies for compression ignition engines. Consequently, this study undertakes a physicochemical characterization of diesel particulate matter (DPM) for engines equipped with alternative injection technologies (direct injection and common rail) and alternative fuels (ultra low sulfur diesel, a 20% biodiesel blend, and a synthetic diesel). Particle physical properties were addressed by measuring particle number size distributions, and particle chemical properties were addressed by measuring polycyclic aromatic hydrocarbons (PAHs) and reactive oxygen species (ROS). Particle volatility was determined by passing the polydisperse size distribution through a thermodenuder set to 300 °C. The results from this study, conducted over a four point test cycle, showed that both fuel type and injection technology have an impact on particle emissions, but injection technology was the more important factor. Significant particle number emission (54%-84%) reductions were achieved at half load operation (1% increase-43% decrease at full load) with the common rail injection system; however, the particles had a significantly higher PAH fraction (by a factor of 2 to 4) and ROS concentrations (by a factor of 6 to 16) both expressed on a test-cycle averaged basis. The results of this study have significant implications for the health effects of DPM emissions from both direct injection and common rail engines utilizing various alternative fuels.

Effect on calves of barley naturally contaminated with ochratoxin A and groundnut meal contaminated with low concentrations of aflatoxin B1.

Four groups of six 12-week-old male Friesian calves were fed diets containing 390 to 540 microgram ochratoxin A per kg, 320 to 500 microgram ochratoxin A plus 12 to 13 microgram aflatoxin B1 per kg, 10 to 13 microgram aflatoxin B1 per kg, or a control diet containing neither toxin. At the end of the 87-day experiment there was no evidence of kidney or liver damage in any group of animals as judged by serial plasma and urine enzyme assays, haematological examinations including the assay of blood coagulation factors, gross appearance at autopsy or histopathological assessment at the light microscopic level. Nor was there any significant alteration in serum IgA, IgM, IgG1 and IgG2 levels or in titres to environmental bacterial and viral antigens. Trace amounts of ochratoxin A were detected in kidneys of five out of the 12 calves exposed to this toxin but all 12 kidneys contained residues of the metabolite ochratoxin alpha (less than 5 to 10 microgram/kg). Traces of aflatoxin B1 and M1 were detected in the liver of one of the 12 calves exposed to aflatoxin B1 but nine kidneys contained the metabolite aflatoxin M1 (less than 0.01 to 0.03 microgram/kg). There was no evidence of interaction between the two toxins.

A sample preparation for automated cervical cancer screening.

A procedure for cluster disruption, cell dispersal and the production of a monolayer of cells from fluid suspensions for automated cell-scanning machines in an interactive system has been developed. The combination of 0.1 per cent dithiothreitol and 40 per cent alcohol in a balanced salt solution provides a self-limiting form of mucolysis which is completed by a controlled syringing regime to produce an optimally dispersed cell sample without the production of cell debris from the more effete cells. The induction of a positive charge on a microscope slide to attract the negatively charged cells has been achieved by coating the slides with the cationic polymer, polylysine. The cells appear to be sufficiently well attached to permit wet fixation and subsequent stain processing without loss. Quantitative data is given to demonstrate the superior cell presentation that is achieved by this new technique for automated scanning.

Abatement of ammonia and hydrogen sulfide emissions from a swine lagoon using a polymer biocover.

The purpose of this research was to determine the efficiency of a polymer biocover for the abatement of H2S and NH3 emissions from an east-central Missouri swine lagoon with a total surface area of 7800 m2. The flux rate of NH3, H2S, and CH4 was monitored continuously from two adjacent, circular (d = 66 m) control and treatment plots using a nonintrusive, micrometeorological method during three independent sampling periods that ranged between 52 and 149 hr. Abatement rates were observed to undergo a temporal acclimation event in which NH3 abatement efficiency improved from 17 to 54% (p = < 0.0001 to 0.0005) and H2S abatement efficiency improved from 23 to 58% (p < 0.0001) over a 3-month period. The increase in abatement efficiency for NH3 and H2S over the sampling period was correlated with the development of a stable anaerobic floc layer on the bottom surface of the biocover that reduced mass transfer of NH3 and H2S across the surface. Analysis of methanogenesis activity showed that the biocover enhanced the rate of anaerobic digestion by 25% when compared with the control. The biocover-enhanced anaerobic digestion process was shown to represent an effective mechanism to counteract the accumulation of methanogenic substrates in the biocovered lagoon.

Response of Acala cotton to nitrogen rates in the San Joaquin Valley of California.

The responses of Acala cotton (Gossypium hirsutum L.) in California to a range of applied nitrogen (N) treatments were investigated in a 5-year, multisite experiment. The experiment's goals were to identify crop growth and yield responses to applied N and provide information to better assess the utility of soil residual N estimates in improving fertilizer management. Baseline fertilizer application rates for the lowest applied N treatments were based on residual soil nitrate-N (NO3-N) levels determined on soil samples from the upper 0.6 m of the soil collected prior to spring N fertilization and within 1 week postplanting each year. Results have shown positive cotton lint yield responses to increases in applied N across the 56 to 224 kg N/ha range in only 41% (16 out of 39) of test sites. Soil NO3-N monitoring to a depth of 2.4 m in the spring (after planting) and fall (postharvest) indicate most changes in soil NO3- occur within the upper 1.2 m of soil. However, some sites (those most prone to leaching losses of soluble nutrients) also exhibited net increases in soil NO3-N in the 1.2- to 2.4-m depth zone when comparing planting time vs. postharvest data. The lack of yield responses and soil NO3-N accumulations at some sites indicate that more efforts should be put into identifying the amount of plant N requirements that can be met from residual soil N, rather than solely from fertilizer N applications.

Aflatoxin B1 in dairy concentrates and other animal feedstuffs.

Over a period of 13 years 740 samples of various animal feedstuffs were analysed for the presence of aflatoxin B1. Nearly 500 were suspected of causing disease in farm animals but aflatoxin B1 could be detected in only 13.6 per cent of them. Groundnut meal samples nearly always contained the toxin but compounded feeds were contaminated to a varying extent. In particular, none could be detected in 62 poultry feeds. Where mycotoxicosis was suspected in dairy cattle, aflatoxin B1 was present at levels of more than 30 micrograms per kg in about 27 per cent of associated feed samples. In other dairy feeds (178 samples) this level of contamination was present in only about 9 per cent of samples. Concentrations of aflatoxin B1 likely to produce toxic effects (100 micrograms per kg and above) were present in about 4 per cent of suspect dairy concentrates but in 1 per cent or less of others. Contamination of dairy concentrates with aflatoxin B1 is usually at such a level that cows probably excrete the toxic metabolite aflatoxin M1 in milk at very low concentrations of 0.1 micrograms per litre or less.

Investigation of suspected cases of mycotoxicosis in farm animals in Britain.

Mycotoxins were detected in 13 out of 131 feed samples examined over two years. Screening of feeds associated with cases of suspected mycotoxicosis occurring in farm animals over a further 12 month period showed that most incidents occurred during the winter and involved mainly cattle and pigs fed concentrates. A haemorrhagic syndrome in cattle and abortions in sows were most frequently connected with mouldy food. One or more known toxins (the aflatoxins, ochratoxin A, sterigmatocystin and zearalenone) were detected in three out of 65 cases and a wide variety of fungi were isolated. Toxicity to experimental animals was demonstrated in four out of 22 samples.

The failure of trichothecene mycotoxins and whole cultures of Fusarium tricinctum to cause experimental haemorrhagic syndromes in calves and pigs.

Piglets and calves were dosed orally with pure diacetoxyscirpenol (DAS) and T-2 toxin, crude extracts of Fusarium tricinctum containing T-2 toxin, and whole cultures of F tricinctum containing T-2 toxin at a constant daily rate of 0.1 mg toxin per kg body-weight (piglets) or 0.2 mg toxin per kg body-weight (calves). The treatment continued for periods of seven to 78 days but it failed to induce clinical haemorrhagic syndromes. Increasing the dose of F tricinctum culture five-fold for eight days following 78 days at the lower dose was equally ineffective. The lack of an effect by daily intakes of toxin that could have been ingested with naturally contaminated feedstuffs suggests that DAS, T-2 toxin and other metabolites of F tricinctum probably have little or no part to play in the aetiology of feed associated haemorrhagic disease.

Development of Ecological Land Classification and mapping in support of forest management in northern Newfoundland, Canada.

For the sustainable development of forest land, as recently prescribed by the Canadian Forest Strategy, a land classification project in northern Newfoundland was initiated to support the local forest management activities. The method adopted here is a modification of the Canadian Committee for Ecological Land Classification's (CCELC) system, and it applies various levels of mapping to uniform areas based on geomorphology, soils, vegetation, climate, water, and fauna.In this study, all CCELC levels were mapped; resulting maps were digitized and imported into a Geographic Informations System (GIS). The GIS data base contained the following maps: 1) digital terrain model, 2) bedrock geology, 3) surficial geology, 4) forest inventory, and 5) various levels of the ecological land classification, including Vegetation Types at the lowest level. In addition to the mapping, mensurational data were analyzed to provide stand and stock tables for each of the forest types, including growth curves that could be entered into specific forest growth modelling systems to predict wood supply scenarios based upon different management interventions.

Site characteristics, growth and nutrition of natural red pine stands in newfoundland.

Red pine (Pinus resinosa Ait.) is rare (< 15 000 mature trees) in Newfoundland and is known from only 22 locations in the central region. Red pine occupies 3 major site types in Newfoundland: 1) red pine on medium-textured sands (RP1), 2) red pine on coarse-textured glaciofluvial deposits (RP2), and 3) red pine on Folisols over bedrock (RP3). The succession of red pine site types after cutting is from red pine to Kalmia-black spruce (Picea mariana (Mill.) B.S.P.) for RP1, and to Cladonia-Kalmia-black spruce for types RP2 and RP3. Succession after fire is usually to the pre-fire type, but this depends on the severity of the fire.Although occupying a relatively poor site, red pine at 60-70 years reaches heights in excess of 18 m, dbh in excess of 40 cm, and individual tree volumes greater than 1 m(3) were recorded in 75 stemanalyzed fire-killed trees. Black spruce on that same site produces less than one-third that volume in 60 years. Merchantable volume of 140-280 m(3) ha(-1) were recorded i.e., Canada Land Inventory (CLI) forest capability class 5 and class 4 ratings. This raises the CLI rating two capability classes if red pine were occupying these poor quality sites over black spruce. In terms of nutrition, even the best growing red pine are nitrogen (N) deficient as shown by foliar analysis. All natural stands have foliar N concentrations below 1.3% which is the critically low level shown in the literature. Immediately after fire, foliar concentrations reach this level but are usually about 1% or less. Most other nutrients are low but are within the generally reported adequate levels in testing for P, K, Ca and Mg.Fire influences soil nutrient availability as pH increases in the RP1 type. Burning temperature also affects soil pH and the understory vegetation. The RP2 type loses more N in hotter burns on this site type and more N is tied up in these ortstein hardpan soils. The pattern of regeneration following wildfire is related to slope, density, age and species mixture of the stand as well as the thickness and composition of the duff layer.