Influence of diesel fuel on seed germination

The use of plant-based systems to remediate contaminated soils has become an area of intense scientific study in recent years and it is apparent that plants which grow well in contaminated soils need to be identified and screened for use in phytoremediation technologies. This study investigated the effect of diesel fuel on germination of selected plant species. Germination response varied greatly with plant species and was species specific, as members of the same plant family showed differential sensitivity to diesel fuel contamination. Differences were also seen within plant subspecies. At relatively low levels of diesel fuel contamination, delayed seed emergence and reduced percentage germination was observed for the majority of plant species investigated. Results suggest the volatile fraction of diesel fuel played an influential role in delaying seed emergence and reducing percentage germination. In addition, the remaining diesel fuel in the soil Lidded to this inhibitory effect on germination by physically impeding water and oxygen transfer between the seed and the surrounding soil environment, thus hindering the germination response

City strategy : final evaluation

The City Strategy (CS) concept was first announced in the 2006 Welfare Reform Green Paper – A new deal for welfare: Empowering people to work. CS was designed at a time of growth in the national economy to combat enduring pockets of entrenched worklessness and poverty in urban areas by empowering local institutions to come together in partnerships to develop locally sensitive solutions. It was premised on the idea that developing a better understanding of the local welfare to work arena would allow partnerships to align and pool funding and resources to reduce duplication of services and fill gaps in provision. The ‘theory of change’ underlying CS suggested that such an approach would result in more coordinated services which would be able to generate extra positive outcomes in terms of getting people into jobs and sustaining them in employment over and above existing provision. CS was initially set to run for two years from April 2007 to March 2009 in 15 CS Pathfinder (CSP) areas, varying in size from five wards in one town through single local authority areas to subregional groupings of multiple local authority areas, across Great Britain. In July 2008, the Secretary of State for Work and Pensions announced an extension for a further two years to March 2011. In April 2009, two local areas in Wales, which were in receipt of monies from the Deprived Areas Fund (DAF), were invited by the Department for Work and Pensions (DWP) to form local partnerships with a similar remit to the CSPs, albeit more limited in scope – to develop locally sensitive solutions to economic inactivity, to the CSPs. During the period that the CS initiative was operational, economic conditions changed markedly with a severe recession, followed by fragile recovery. The CSPs had to cope with ongoing changes in policy throughout the lifetime of the CS initiative, including a General Election and a new Coalition Government at Westminster early in the fourth year. While policy changes are a fact of life for local practitioners operating in the welfare to work arena, the global recession in 2008/09 marked a fundamental change in the context in which local partnerships operated

Cognitive bias, scepticism and understanding

In recent work, Mark Alfano (2012; 2014) and Jennifer Saul (2013) have put forward a similar kind of provocative sceptical challenge. Both appeal to recent literature in empirical psychology to show that our judgments across a wide range of cases are riddled with unreliable cognitive heuristics and biases. Likewise, they both conclude that we know a lot less than we have hitherto supposed, at least on standard conceptions of what knowledge involves. It is argued that even if one grants the empirical claims that Saul and Alfano make, the sceptical conclusion that they canvass might not be as dramatic as it first appears. It is further argued, however, that one can reinstate a more dramatic sceptical conclusion by targeting their argument not at knowledge but rather at the distinct (and distinctively valuable) epistemic standing of understanding

Novel asymmetric microenvironments for the separation of enantiomers of chiral drugs and natural products

The determination of enantiomeric composition is of great importance in the pharmaceutical and natural product industries where two enantiomeric forms of a chiral molecule can have very different biological activities. Homochiral derivatization of enantiomeric compounds followed by chromatographic separation of the resultant diastereoisomers on conventional achiral columns has proved to be a cheap and useful method for enantioquantification. Reactions of simple alkyl halides with alcohols, acids, thiols and amines are known. Novel homochiral derivatization procedures based on two such reactions have been investigated. In these reactions, homochiral alkyl halide reagents, some of which are prepared here for the first time, have been based on proline and lactone ring systems and chiral esters. Another derivatization approach utilising highly reactive and novel homochiral chloromethyl ether reagents has proved successful. For example, racemic secondary alcohols when derivatized with (S)-(+)- tetrahydro-5-oxo-2-furanmethyl chloromethyl ether, have been separated to baseline. Quantification of 1% of one enantiomer in the presence of 99% of its antipode has been achieved. The presence of 5 bonds between the chiral centres of such diastereisomeric derivatives makes their separation an interesting result. Indeed, further work on the effects of spacing between chiral centres indicated that the separation efficiency of these systems were in the order 3>44>5 is expected. The chloromethyl ether reagents, unlike the alkyl halides, do not have a proton on the atom P to the halide and thus cannot undergo dehydrohalogénation as a side reaction. The mild reaction conditions, employing diisopropylethylamine as a hindered non nucleophilic base make such derivatizations amenable to compounds containing acid and base sensitive functions. Assessment of the performances of both the alkyl halide and chloromethyl ether reagents are made by comparison with enantioseparations achieved when using N-acetyl-(S)-(-)-prolyl chloride and (+)-(trans)- chrysanthemoyl chloride reagents. Synthetic procedures for the preparation of all the homochiral reagents are reported. NMR techniques were investigated by employing modified cyclodextrins in an attempt to form diastereoisomeric inclusion complexes with chiral analytes. It was hoped that differences in their spectra would enable enantioquantification. Initial attempts at preparing novel homochiral polyesters by the condensation polymerisation of polyethylene glycol (400) with homochiral diacids were made. Such polymers may have use as homochiral chromatographic stationary phases

Locating the Variability of Soil Water Holding Capacity and Understanding Its Effects on Deficit Irrigation and Cotton Lint Yield

Precision irrigation equipment such as variable-rate center pivots is readily available to Tennessee growers and producers; however, little research exists describing its application to cotton grown in Tennessee. In order to optimize the use of variable-rate irrigation equipment and water resources, two experiments were performed to determine (1) whether or not ground-penetrating radar (GPR) and electrical conductivity (EC) measurements can be used to delineate variable-rate irrigation zones and (2) examine the response of cotton lint yield to varying rates and duration of irrigation. GPR and EC measurements were recorded, validated using soil cores, and used to identify the subsurface variability of soil texture, depth to a sandy layer (DTS), and soil available water holding capacity (AWHC) on a research location in Jackson, Tennessee. A strong, linear relationship between DTS and AWHC (R2=0.92) indicated that a high resolution map of textural differences would provide a good approximation of AWHC variability. Both AWHC and DTS were related (R2\u3e70%) to both GPR and EC data. Variable-rate irrigation zones representing textural and AWHC variability were successfully partitioned using a combination of GPR and EC data. Past cotton research regarding lint yield response to irrigation suggests that cotton irrigated on soils with a high AWHC might be negatively affected by the high irrigation rates required to maximize the yield of cotton grown on low AWHC soils. Using three major soil blocks identified using GPR and EC data, varying levels of irrigation rate and duration were applied to cotton grown on soils with a low, moderate, and high AWHC. Statistical analysis shows that cotton grown on low AWHC soils responded differently (p=0.06) to irrigation treatments than cotton grown on moderate and high AWHC soils. In 2011, irrigating at 1.5 inches per week from first bloom until cracked boll resulted in approximately 1081 pounds of lint per acre increase in low AWHC soils but only 167 pounds of lint per acre increase in high AWHC soils. Also, this irrigation treatment resulted in a significant (alpha=0.10) lint yield decrease below maximum yield for high AWHC soils

Effect of diesel fuel on growth of selected plant species

Diesel oil is a complex mixture of hydrocarbons with an average carbon number of C8– C26. The majority of components consist of alkanes, both straight chained and branched and aromatic compounds including mono-, di- and polyaromatic hydrocarbons. Regardless of this complexity, diesel oil can be readily degraded by a number of soil microorganisms making it a likely candidate for bioremediation. The concept of using plants to enhance bioremediation, termed phytoremediation, is a relatively new area of scientific interest. It is particularly applicable to diesel oil contamination as diesel oil generally contaminates the top few metres of soil (surface soil) and contamination is not uniform throughout the site. By encouraging plants to grow on diesel oil contaminated soil, conditions are improved for the microbial degradation of the contaminant. During this study, establishing plants on diesel oil contaminated soil proved difficult. Diesel oil is phytotoxic to plants at relatively low concentrations. At concentrations below this phytotoxic level, the development of plants grown in diesel oil contaminated soil differs greatly from plants grown in uncontaminated soil. Tolerance of plants to diesel oil and ability to germinate in diesel oil contaminated soil varied greatly between plant species as well as within plant species. The broadest differences in germination were seen within the grasses with certain species thriving in low levels of contamination (e.g. Creeping bent) while others were intolerant of diesel oil contamination (e.g. Rough meadow grass). The herbs, legumes and commercial crops screened appeared to be largely unaffected by low levels of diesel oil contamination (25 g diesel kg−1). At the higher level of contamination (50 g diesel kg−1), half of the twenty two plants species screened failed to reach a germination rate equal to 50% of the control rate. Two species of grass failed to germinate at all at this contamination level. Plant species that successfully germinated and grew were studied further to determine the effect of diesel oil contamination on the later stages of plant development. This work investigates the effect of diesel oil on plant growth and development

Ionic interchange in stearic acid sols and the mechanism of coagulation

(1) The production of acidity in stearic acid sole by neutral salts has been investigated by means of the quinhydrone electrode.(2) The variation in the degree of ionic interchange with variation in (1) concentration of sol, (2) concentration of salt, (3) acidity, and (4) nature of salt has been studied.(3) The influence of electrolytes upon the stability of the sol has been examined, and the conclusion reached that there is a close connection between the coagulative ability of a salt and the tendency for it to liberate hydrogen ions.(4) The results have been discussed with reference to the general theory of coagulation