Estimating the spatial scale of herbicide and soil interactions by nested sampling, hierarchical analysis of variance and residual maximum likelihood

An unbalanced nested sampling design was used to investigate the spatial scale of soil and herbicide interactions at the field scale. A hierarchical analysis of variance based on residual maximum likelihood (REML) was used to analyse the data and provide a first estimate of the variogram. Soil samples were taken at 108 locations at a range of separating distances in a 9 ha field to explore small and medium scale spatial variation. Soil organic matter content, pH, particle size distribution, microbial biomass and the degradation and sorption of the herbicide, isoproturon, were determined for each soil sample. A large proportion of the spatial variation in isoproturon degradation and sorption occurred at sampling intervals less than 60 m, however, the sampling design did not resolve the variation present at scales greater than this. A sampling interval of 20-25 m should ensure that the main spatial structures are identified for isoproturon degradation rate and sorption without too great a loss of information in this field.

Gaming and social interactions in the rehabilitation of brain injuries: a pilot study

Physical rehabilitation of brain injuries and strokes is a time consuming and costly process. Over the past decade several studies have emerged looking at the use of highly sophisticated technologies, such as robotics and virtual reality to tap into the needs of clinicians and patients. While such technologies can be a valuable tool to facilitate intensive movement practice in a motivating and engaging environment, success of therapy also depends on self-administered therapy beyond hospital stay. With the emergence of low-cost gaming consoles such as the Nintendo Wii, new opportunities arise for home-therapy paradigms centred on social interactions and values, which could reduce the sense of isolation and other depression related complications. In this paper we examine the potential, user acceptance and usability of an unmodified Nintendo Wii gaming console as a low-cost treatment alternative to complement current rehabilitation programmes.

Genomic and genetic analyses of diversity and plant interactions of Pseudomonas fluorescens

Background: Pseudomonas fluorescens are common soil bacteria that can improve plant health through nutrient cycling, pathogen antagonism and induction of plant defenses. The genome sequences of strains SBW25 and Pf0-1 were determined and compared to each other and with P. fluorescens Pf-5. A functional genomic in vivo expression technology (IVET) screen provided insight into genes used by P. fluorescens in its natural environment and an improved understanding of the ecological significance of diversity within this species. Results: Comparisons of three P. fluorescens genomes (SBW25, Pf0-1, Pf-5) revealed considerable divergence: 61% of genes are shared, the majority located near the replication origin. Phylogenetic and average amino acid identity analyses showed a low overall relationship. A functional screen of SBW25 defined 125 plant-induced genes including a range of functions specific to the plant environment. Orthologues of 83 of these exist in Pf0-1 and Pf-5, with 73 shared by both strains. The P. fluorescens genomes carry numerous complex repetitive DNA sequences, some resembling Miniature Inverted-repeat Transposable Elements (MITEs). In SBW25, repeat density and distribution revealed 'repeat deserts' lacking repeats, covering approximately 40% of the genome. Conclusions: P. fluorescens genomes are highly diverse. Strain-specific regions around the replication terminus suggest genome compartmentalization. The genomic heterogeneity among the three strains is reminiscent of a species complex rather than a single species. That 42% of plant-inducible genes were not shared by all strains reinforces this conclusion and shows that ecological success requires specialized and core functions. The diversity also indicates the significant size of genetic information within the Pseudomonas pan genome.

Incorporation of in situ and biomarker assays in higher-tier assessment of the aquatic toxicity of insecticides

This study was designed to test the feasibility of integrating in situ, single species exposures and biomarker analysis into microcosm studies. Experimental ponds were dosed with pirimiphos methyl (PM) and lindane. C. riparius fourth instar larvae were deployed for 48 h on nine separate occasions during the study period before and after treatment. Surviving larvae were analysed for acetylcholinesterase activity (AChE). Survival and biomarker data were compared to chironomid assemblage analysis by monitoring insects emerging from the microcosms. Survival of chironomids within the in situ systems commenced on day + 16 after treatment with 31.6% and 53.3% survival in the lindane and PM treated ponds, respectively. In contrast, the first emergence from the microcosms occurred on days + 27, in respect to lindane, and + 59 for the PM treated ponds. Thus the in situ bioassay was able to demonstrate gradual reduction in toxicity within the sediment before this was evident from macroinvertebrate monitoring. Significant ACNE inhibition was only detected on exposure to PM. Levels decreased from 75% on day + 16 to 26% by day +29. The biomarker analysis confirmed that, by the end of the study, the insecticide was no longer exerting an effect. We discuss how the use of in situ bioassays could also aid comparison of microcosm studies by adding a standardized dimension. (C) 2003 Elsevier Ltd. All rights reserved.

Multiple domestications and their taxonomic consequences: the example of Phaseolus vulgaris

The evolutionary history of P. vulgaris is important to those working on its genetic resources, but is not reflected in its infraspecific taxonomy. Genetic isolation of wild populations between and also within Middle and South America has resulted in morphological and molecular differentiation. Populations from northern and southern ends of the range are assigned to different gene pools, though intermediates occur in intervening areas. Chloroplast haplotypes suggest three distinct lineages of wild beans and several intercontinental dispersals. The species was domesticated independently in both Middle and South America, probably several times in Middle America. This, together with further differentiation under human selection, has produced distinct races among domesticated beans. The informal categories of wild versus domesticated, gene pool, and race convey the evolutionary picture more clearly than the formal categories provided by the Codes of Nomenclature for wild or cultivated plants.

Insect and bird interactions

This unique book is the first of its kind to explore the diversity of interactions between insects and birds. A group of international experts enthusiastically agreed to contribute to the four sections of the book following the success of an Entomological Club Conference on Insect and Bird Interactions. The first section covers population management issues, discussing effects on birds highly relevant to the planting of large areas of GM crops, new opportunities for increasing biodiversity in farming landscapes, and the novel aspect of managing insects by exploiting birds as biological control agents. This is followed by a section discussing the effects of insecticides on bird populations, and includes a contribution from the RSPB, as well as a re-appraisal of the effects of DDT on raptors. Next, the foraging behaviour of birds on insects is discussed, with chapters also on 'warning' coloration in insects and learning by birds. The first chapter in this section is unusual in having been written by an ophthalmologist and covers colour vision in birds, more specifically ultraviolet vision in relation to insect coloration. Finally, the authors look at insects that are parasites of birds or feed on the detritus in nests, and review the ecology and evolution of the co-adaptation of insect ectoparasites with birds. Insect and Bird Interactions is unparalleled in scope and coverage and will be of interest to entomologists, ornithologists, and ecologists alike.

Supramolecular hydrogen-bond structures and magnetic interactions in basal-apical, dinuclear, azide-bridged copper(II) complexes

The synthesis, characterisation, X-ray single crystal structures and magnetic properties of three new basal-apical mu(2)-1,1-azide-bridged complexes [(CuLN3)-N-1](2) (1), [(CuLN3)-N-2](2) (2) and [(CuLN3)-N-3](2) (3) with very similar tridentate Schiff-base blocking ligands {HL1 = N-[2-(ethylamino) ethyl] salicylaldimine; HL2 = 7-(ethylamino)-4-methyl-5-azahept-3-en-2-one; HL3 = 7-amino-4-methyl-5-azaoct-3-en-2-one} have been reported [complex 1: monoclinic, P2(1)/c, a = 8.390(2), b = 7.512(2), c = 19.822(6) Angstrom, beta = 91.45(5)degrees; complex 2: monoclinic, P2(1)/c, a = 8.070(9), b = 9.787(12), c = 15.743(17) A, beta = 98.467(10)degrees; complex 3: monoclinic, P2(1)/n, a = 5.884(7), b = 16.147(18), c = 11.901(12) Angstrom, beta = 90.050(10)degrees]. The structures consist of neutral dinuclear entities resulting from the pairing of two mononuclear units through end-on azide bridges connecting an equatorial position of one copper centre to an axial position of the other, The copper ions adopt a (4+1) square-based geometry in all the complexes. In complex 2, there is no inter-dimer hydrogen-bonding. However, complexes 1 and 3 form two different supramolecular structures in which the dinuclear entities are linked by H-bonds giving one-dimensional systems. Variable temperature (300-2 K) magnetic-susceptibility measurements and magnetisation measurements at 2 K reveal that all three complexes have antiferromagnetic coupling. Magneto-structural correlations have been made taking into consideration both the azido bridging ligands and the existence of intermolecular hydrogen bonds. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).

Novel temperature-responsive water-soluble copolymers based on 2-hydroxyethylacrylate and vinyl butyl ether and their interactions with poly(carboxylic acids)

Novel water-soluble amphiphilic copolymers have been synthesized by free radical copolymerization of 2-hydroxyethylacrylate with vinyl butyl ether. In water these copolymers exhibit lower critical solution temperature, which depends on the content of hydrophobic vinyl butyl ether units. The interaction between these copolymers and poly(acrylic acid) or poly(methacrylic acid) in aqueous solutions results in formation of interpolymer complexes stabilized by hydrogen bonds and hydrophobic interactions. An increase in hydrophobicity of the copolymers leads to the enhancement of their complex formation ability with respect to poly(acrylic acid) and poly(methacrylic acid). Poly(methacrylic acid) forms stronger complexes with the copolymers when compared with poly(acrylic acid). The complexes exhibit dual sensitivity to pH- and temperature and this property may be easily adjusted regulating the strength of interaction. (c) 2005 Wiley Periodicals, Inc.

Perceptual compensation for reverberation in speech identification: effects of single-band, multiple-band and wideband noise contexts

Perceptual effects of room reverberation on a "sir" or "stir" test-word can be observed when the level of reverberation in the word is increased, while the reverberation in a surrounding 'context I utterance remains at a minimal level. The result is that listeners make more "sit" identifications. When the context's reverberation is also increased, to approach the level in the test word, extrinsic perceptual compensation is observed, so that the number of listeners' "sir" identifications reduces to a value similar to that found with minimal reverberation. Thus far, compensation effects have only been observed with speech or speech-like contexts in which the short-term spectrum changes as the speaker's articulators move. The results reported here show that some noise contexts with static short-term spectra can also give rise to compensation. From these experiments it would appear that compensation requires a context with a temporal envelope that fluctuates to some extent, so that parts of it resemble offsets. These findings are consistent with a rather general kind of perceptual compensation mechanism; one that is informed by the 'tails' that reverberation adds at offsets. Other results reported here show that narrow-band contexts do not bring about compensation, even when their temporal-envelopes are the same as those of the more effective wideband contexts. These results suggest that compensation is confined to the frequency range occupied by the context, and that in a wideband sound it might operate in a 'band by band' manner.

Effects of food structure and ingredient interactions on antioxidant capacity

Foods are complex biological materials, and the lipids within the food are susceptible to lipid oxidation, which is retarded by antioxidants. The precise structure and composition of the food may affect the antioxidant activity quite strongly in some cases. Solubility of the antioxidant in the phases present is one of the main parameters that affects the variation in antioxidant activity with phase composition of food. Polar antioxidants are more effective in oils, whereas non-polar antioxidants are more effective in oil-in-water emulsions. Antioxidant activity has been reported in a range of different media, including oils, emulsions, liposomes, microemulsions, fish and meat muscles, and the antioxidant activity may vary from one medium to another. Synergy between antioxidants may also vary from one medium to another. Interactions with metals and with proteins affect antioxidant activity and these interactions are also dependent on the phases present.

Beyond antioxidants: the cellular and molecular interactions of flavonoids and how these underpin their actions on the brain

The consumption of flavonoid-rich foods and beverages has been suggested to limit the neurodegeneration associated with a variety of neurological disorders and to prevent or reverse normal or abnormal deteriorations in cognitive performance. Flavonoids mediate these effects via a number of routes, including a potential to protect neurons against injury induced by neurotoxins, an ability to suppress neuroinflammation and a potential to promote memory, learning and cognitive function. Originally, it was thought that such actions were mediated by the antioxidant capacity of flavonoids. However, their limited absorption and their low bioavailability in the brain suggest that this explanation is unlikely. Instead, this multiplicity of effects appears to be underpinned by three separate processes: first, through their interactions with important neuronal and glial signalling cascades in the brain, most notably the phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase pathways that regulate pro-survival transcription factors and gene expression; second, through an ability to improve peripheral and cerebral blood flow and to trigger angiogenesis and neurogenesis in the hippocampus; third, by their capacity to directly react with and scavenge neurotoxic species and pro-inflammatory agents produced in the brain as a result of both normal and abnormal brain ageing. The present review explores the potential inhibitory or stimulatory actions of flavonoids within these three systems and describes how such interactions are likely to underlie neurological effects.