Mitigation options for sediment and phosphorus loss from winter-sown arable crops

Sediment and P inputs to freshwaters from agriculture are a major problem in the United Kingdom (UK). This study investigated mitigation options for diffuse pollution losses from arable land. Field trials were undertaken at the hillslope scale over three winters at three UK sites with silt (Oxyaquic Hapludalf), sand (Udic Haplustept), and clay (Typic Haplaquept) soils. None of the mitigation treatments was effective in every year trialled, but each showed overall average reductions in losses. Over five site years, breaking up the compaction in tramlines (tractor wheel tracks) using a tine reduced losses of sediment and P to losses similar to those observed from areas without tramlines, with an average reduction in P loss of 1.06 kg TP ha(-1) Compared to traditional plowing, TP losses under minimum tillage were reduced by 0.30 kg TT ha(-1) over five site years, TP losses under contour cultivation were reduced by 0.30 kg TP ha(-1) over two site years, and TP losses using in-field barriers were reduced by 0.24 kg TP ha(-1) over two site years. In one site year, reductions in losses due to crop residue incorporation were nor significant. Each of the mitigation options trialled. is associated with a small cost at the farm-scale of up to 5 pound ha(-1), or with cost savings. The results indicate that each of the treatments his the potential to be a cost-effective mitigation option, but that tramline management is the most promising treatment, because tramlines dominate sediment and P transfer in surface runoff from arable hillslopes.

Inbreeding and loss of genetic variation in a reintroduced population of Mauritius Kestrel

Many populations have recovered from severe bottlenecks either naturally or through intensive conservation management. In the past, however, few conservation programs have monitored the genetic health of recovering populations. We conducted a conservation genetic assessment of a small, reintroduced population of Mauritius Kestrel (Falco punctatus) to determine whether genetic deterioration has occurred since its reintroduction. We used pedigree analysis that partially accounted for individuals of unknown origin to document that (1) inbreeding occurred frequently (2.6% increase per generation; N-el = 18.9), (2) 25% of breeding pairs were composed of either closely or moderately related individuals, (3) genetic diversity has been lost from the population (1,6% loss per generation; N-ev = 32.1) less rapidly than the corresponding increase in inbreeding, and (4) ignoring the contribution of unknown individuals to a pedigree will bias the metrics derived from that pedigree, ultimately obscuring the prevailing genetic dynamics. The rates of inbreeding and loss of genetic variation in the subpopulation of Mauritius Kestrel we examined were extreme and among the highest yet documented in a wild vertebrate population. Thus, genetic deterioration may affect this population's long-term viability. Remedial conservation strategies are needed to reduce the impact of inbreeding and loss of genetic variation in this species, We suggest that schemes to monitor genetic variation after reintroduction should be an integral component of endangered species recovery programs

Consumer welfare and the loss induced by withholding information: The case of BSE in Italy

The paper develops a measure of consumer welfare losses associated with withholding it formation about a possible link between BSE and vCJD. The Cost of Ignorance (COI) is measured by comparing the utility of the informed choice with the utility of the uninformed choice, under conditions of improved information. Unlike previous work that is largely based on a single equation demand model, the measure is obtained retrieving a cost,function from a dynamic Almost Ideal Demand System. The estimated perceived loss for Italian consumers due to delayed information ranges from 12 percent to 54 percent of total meat expenditure, depending on the month assumed to embody correct beliefs about the safety level of beef.

Constrained models of evolution lead to improved prediction of functional linkage from correlated gain and loss of genes

Motivation: We compare phylogenetic approaches for inferring functional gene links. The approaches detect independent instances of the correlated gain and loss of pairs of genes from species' genomes. We investigate the effect on results of basing evidence of correlations on two phylogenetic approaches, Dollo parsminony and maximum likelihood (ML). We further examine the effect of constraining the ML model by fixing the rate of gene gain at a low value, rather than estimating it from the data. Results: We detect correlated evolution among a test set of pairs of yeast (Saccharomyces cerevisiae) genes, with a case study of 21 eukaryotic genomes and test data derived from known yeast protein complexes. If the rate at which genes are gained is constrained to be low, ML achieves by far the best results at detecting known functional links. The model then has fewer parameters but it is more realistic by preventing genes from being gained more than once. Availability: BayesTraits by M. Pagel and A. Meade, and a script to configure and repeatedly launch it by D. Barker and M. Pagel, are available at http://www.evolution.reading.ac.uk .

Aqueous peroxyl radical exposure to THP-1 cells causes glutathione loss followed by protein oxidation and cell death without increased caspase-3 activity

Protein oxidation within cells exposed to oxidative free radicals has been reported to occur in an uninhibited manner with both hydroxyl and peroxyl radicals. In contrast, THP-1 cells exposed to peroxyl radicals (ROO center dot) generated by thermo decomposition of the azo compound AAPH showed a distinct lag phase of at least 6 h, during which time no protein oxidation or cell death was observed. Glutathione appears to be the source of the lag phase as cellular levels were observed to rapidly decrease during this period. Removal of glutathione with buthionine sulfoxamine eliminated the lag phase. At the end of the lag phase there was a rapid loss of cellular MTT reducing activity and the appearance of large numbers of propidium iodide/annexin-V staining necrotic cells with only 10% of the cells appearing apoptotic (annexin-V staining only). Cytochrome c was released into the cytoplasm after 12 h of incubation but no increase in caspase-3 activity was found at any time points. We propose that the rapid loss of glutathione caused by the AAPH peroxyl radicals resulted in the loss of caspase activity and the initiation of protein oxidation. The lack of caspase-3 activity appears to have caused the cells to undergo necrosis in response to protein oxidation and other cellular damage. (c) 2007 Elsevier B.V. All rights reserved.

Loss of 3-chlorotyrosine by inflammatory oxidants: Implications for the use of 3-chlorotyrosine as a bio-marker in vivo

Activated neutrophils generate the potent oxidant hypochlorous acid (HOCl) from the enzyme myeloperoxidase (MPO). A proposed bio-marker for MPO-derived HOCl in vivo is 3-chlorotyrosine, elevated levels of which have been measured in several human inflammatory pathologies. However, it is unlikely that HOCl is produced as the sole oxidant at sites of chronic inflammation as other reactive species are also produced during the inflammatory response. The work presented shows that free and protein bound 3-chlorotyrosine is lost upon addition of the pro-inflammatory oxidants, HOCl, peroxynitrite, and acidified nitrite. Furthermore, incubation of 3-chlorotyrosine with activated RAW264.7 macrophages or neutrophil-like HL-60 cells resulted in significant loss of 3-chlorotyrosine. Therefore, at sites of chronic inflammation where there is concomitant ONOO- and HOCl formation, it is possible measurement of 3-chlorotyrosine may represent an underestimate of the true extent of tyrosine chlorination. This finding could account for some of the discrepancies reported between 3-chlorotyrosine levels in tissues in the literature. (c) 2008 Elsevier Inc. All rights reserved.

Permanent changes in growth and physiology of Bacillus subtilis ToC46 after loss of a recombinant plasmid

The physiology and growth of plasmid-bearing Bacillus subtilis carrying plasmid pPFF1, the non-transformed host, and cells after loss of the plasmid (so-called plasmid-cured cells) were investigated. It was found that, following plasmid loss, cells exhibited phenotypic characteristics different from those of the non-transformed host strains. Compared to plasmid-bearing cells and non-transformed host cells, an approximate 25% increase in the maximum specific growth rate and a more rapid increase in total RNA per unit cell mass were observed in plasmid-cured cells. The total enthalpy associated with irreversible denaturation events was determined in whole cells by differential scanning calorimetry. This showed higher enthalpies for plasmid-cured cells compared with the non-transformed host, which suggests increased ribosome numbers. The result from cellular DNA hybridisation suggests that there was no direct evidence of plasmid integration into the host chromosome. (C) 2004 Elsevier Inc. All rights reserved.

Suboptimal system recovery from communication loss in a multi-robot localization scenario using EKF algorithms

This paper describes a multi-robot localization scenario where, for a period of time, the robot team loses communication with one of the robots due to system error. In this novel approach, extended Kalman filter (EKF) algorithms utilize relative measurements to localize the robots in space. These measurements are used to reliably compensate "dead-com" periods were no information can be exchanged between the members of the robot group.