Short-term effect of soil disturbance by mechanical weeding on plant available nutrients in an organic vs conventional rotations experiment

The question whether soil disturbance from mechanical weeding in organic systems affects nutrient release from organic matter in compost-amended soil was examined in a long-term organic-versus-conventional rotational cropping system experiment over three years. The experimental design included continuous snap beans, and a fully phased snap beans/fall rye crop rotation sequence. Treatments were combinations of yearly applied fertiliser (synthetic fertiliser, 1× compost, 3× compost) and weed control (herbicide, mechanical weeding). The 1× compost rate was calculated to deliver the equivalent of 50 kg N ha-1: equal to the rate ofN in the synthetic fertiliser treatments. Ion exchange membranes were buried for 24 hours following mechanical weeding in bean plots. Adsorbed ions were then eluted and quantified. Available ammonium-nitrogen was not affected byweeding treatment, but nitrate-nitrogen was consistently less in mechanically weeded plots than in plots treated with herbicide. Principal component analysis of NH4-N, NO3-N, P, K, Ca and Mg availabilities showed distinct groupings of treatments according to fertility treatment rather than weeding treatment. The effect of cropping sequence on available nutrients was pronounced (P ≤ 0.001) only in plots amended with synthetic fertilisers

The effect of harmonized emissions on aerosol properties in global models – an AeroCom experiment

The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA) and one with unified emissions, injection heights, and particle sizes at the source (ExpB). Surprisingly, harmonization of aerosol sources has only a small impact on the simulated diversity for aerosol burden, and consequently optical properties, as the results are largely controlled by model-specific transport, removal, chemistry (leading to the formation of secondary aerosols) and parameterizations of aerosol microphysics (e.g. the split between deposition pathways) and to a lesser extent on the spatial and temporal distributions of the (precursor) emissions. The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversity for these two species was caused by few outliers. The experiment also indicated that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences. These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters) in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies

Gravitational Lensing by Dark Matter Caustics

Dark matter caustics have specific density profiles and, therefore, precisely calculable gravitational lensing properties. We present a formalism which simplifies the relevant calculations, and apply it to four specific cases. In the first three, the line of sight is tangent to a smooth caustic surface. The curvature of the surface at the tangent point is positive, negative or zero. In the fourth case the line of sight passes near a cusp. For each we derive the map between the image and source planes. In some cases, a point source has multiple images and experiences infinite magnification when the images merge. Unfortunately, for the dark matter caustics expected in realistic galactic halo models, the angular resolution required to resolve the multiple images is not presently achievable. A more promising approach aims to observe the distortions caused by dark matter caustics in the images of extended sources such as radio jets.Comment: 36 pages, 11 figure

'Riots engulfed the city':an experimental study investigating the legitimating effects of fire metaphors in discourses of disorder

In Cognitive Linguistic Critical Discourse Studies (CL-CDS), metaphor is identified as a key index of ideology and an important device in the legitimation of social action. From this perspective, metaphor is a cognitive-semiotic operation, invoked by metaphorical expressions in discourse, in which a source frame is mobilised to provide a template for sense-making inside a target frame, leading to particular framing effects. However, the extent to which metaphors in discourse genuinely activate an alternative frame and thereby achieve framing effects has recently been subject to question. Amid calls for more empirical forms of analysis in Critical Discourse Studies, the paper reports two experiments testing the legitimating framing effects of fire metaphors in discourses of disorder. Results show that images of fire and fire metaphors in the absence of competing images facilitate support for police use of water cannon in response to social unrest. The study not only justifies attention to metaphor in CL-CDS but similar effects across semiotic modalities are interpreted as evidence in support of simulation-based theories of metaphor

Genetic Background Can Result in a Marked or Minimal Effect of Gene Knockout (GPR55 and CB2 Receptor) in Experimental Autoimmune Encephalomyelitis Models of Multiple Sclerosis

PMCID: PMC379391

Lack of correlation of stem cell markers in breast cancer stem cells

BACKGROUND: Various markers are used to identify the unique sub-population of breast cancer cells with stem cell properties. Whether these markers are expressed in all breast cancers, identify the same population of cells, or equate to therapeutic response is controversial. METHODS: We investigated the expression of multiple cancer stem cell markers in human breast cancer samples and cell lines in vitro and in vivo, comparing across and within samples and relating expression with growth and therapeutic response to doxorubicin, docetaxol and radiotherapy. RESULTS: CD24, CD44, ALDH and SOX2 expression, the ability to form mammospheres and side-population cells are variably present in human cancers and cell lines. Each marker identifies a unique rather than common population of cancer cells. In vivo, cells expressing these markers are not specifically localized to the presumptive stem cell niche at the tumour/stroma interface. Repeated therapy does not consistently enrich cells expressing these markers, although ER-negative cells accumulate. CONCLUSIONS: Commonly employed methods identify different cancer cell sub-populations with no consistent therapeutic implications, rather than a single population of cells. The relationships of breast cancer stem cells to clinical parameters will require identification of specific markers or panels for the individual cancer

The intrinsic shape of galaxy bulges

The knowledge of the intrinsic three-dimensional (3D) structure of galaxy components provides crucial information about the physical processes driving their formation and evolution. In this paper I discuss the main developments and results in the quest to better understand the 3D shape of galaxy bulges. I start by establishing the basic geometrical description of the problem. Our understanding of the intrinsic shape of elliptical galaxies and galaxy discs is then presented in a historical context, in order to place the role that the 3D structure of bulges play in the broader picture of galaxy evolution. Our current view on the 3D shape of the Milky Way bulge and future prospects in the field are also depicted.Comment: Invited Review to appear in "Galactic Bulges" Editors: Laurikainen E., Peletier R., Gadotti D. Springer Publishing. 24 pages, 7 figure

Dynamic Evolution of a Quasi-Spherical General Polytropic Magnetofluid with Self-Gravity

In various astrophysical contexts, we analyze self-similar behaviours of magnetohydrodynamic (MHD) evolution of a quasi-spherical polytropic magnetized gas under self-gravity with the specific entropy conserved along streamlines. In particular, this MHD model analysis frees the scaling parameter $n$ in the conventional polytropic self-similar transformation from the constraint of $n+\gamma=2$ with $\gamma$ being the polytropic index and therefore substantially generalizes earlier analysis results on polytropic gas dynamics that has a constant specific entropy everywhere in space at all time. On the basis of the self-similar nonlinear MHD ordinary differential equations, we examine behaviours of the magnetosonic critical curves, the MHD shock conditions, and various asymptotic solutions. We then construct global semi-complete self-similar MHD solutions using a combination of analytical and numerical means and indicate plausible astrophysical applications of these magnetized flow solutions with or without MHD shocks.Comment: 21 pages, 7 figures, accepted for publication in APS

Yields and Sward Characteristics of Timothy Cultivars under Grazing

Seven timothy (Phleum pratense L.) cultivars were evaluated over three pasture seasons under rotational grazing to 7 or 11 cm post-grazing heights and regrowth periods of four to seven weeks. There was a trend for the pasture type timothy cultivars to outyield Champ timothy (check). Dry matter yields were lower for the 7 cm than 11 cm post-grazing height. Although the overall cultivar x post-grazing height interaction was not significant (P \u3e 0.05), there was variability in grazing tolerance among timothy cultivars. Yield of Kahu was maintained and vegetative tiller density of Kahu increased over the experimental period under 7 cm grazing. Proportion of vegetative tillers among the cultivars ranged from 0.20 to 0.61 in the primary growth but this proportion increased to 0.95 in the fourth grazing

No association of alcohol use and the risk of ulcerative colitis or Crohn’s disease: data from a European Prospective cohort study (EPIC)

Background The role of long -term alcohol consumption for the risk of developing ulcerative colitis (UC) and Crohn’s disease (CD) is unclear. Aim s For the first time, t o prospectively assess the role of pre -disease alcohol consumption o n the risk of developing UC or CD. Methods Nested within the European Prospective Investigation into Cancer and Nutrition (EPIC - IBD ), incident UC and CD cases and ma tched controls where included. At recruitment, participants completed validated food frequency and lifestyle questionnaires. Alcohol consumption was classified as either: non -use, former, light ( ≤ 0.5 and 1 drink/week), below the recommended limits (BRL) ( ≤ 1 and 2 drinks/day), moderate ( ≤ 2.5 and 5 drinks/day) , or heavy use (>2.5 and >5 drinks/ day) for women and men, respectively ; and was expressed as consumption at enrolment and during lifetime. Conditional logistic regression was applied adjusting for smoking and education , taking light users as the 3 Abstract Background The role of long -term alcohol consumption for the risk of developing ulcerative colitis (UC) and Crohn’s disease (CD) is unclear. Aim s For the first time, t o prospectively assess the role of pre -disease alcohol consumption o n the risk of developing UC or CD. Methods Nested within the European Prospective Investigation into Cancer and Nutrition (EPIC - IBD ), incident UC and CD cases and ma tched controls where included. At recruitment, participants completed validated food frequency and lifestyle questionnaires. Alcohol consumption was classified as either: non -use, former, light ( ≤ 0.5 and 1 drink/week), below the recommended limits (BRL) ( ≤ 1 and 2 drinks/day), moderate ( ≤ 2.5 and 5 drinks/day) , or heavy use (>2.5 and >5 drinks/ day) for women and men, respectively ; and was expressed as consumption at enrolment and during lifetime. Conditional logistic regression was applied adjusting for smoking and education , taking light users as the reference. Results Out of 262,451 participants in 6 countries, 198 UC incident cases/792 controls and 84 CD cases/336 controls were included. At enrolment, 8%/27%/3 2%/2 3%/1 1% UC cases and 7%/2 9%/4 0%/19%/ 5% C D cases were: non -users, light, BRL, moderate and heavy users, respectively. The corresponding figures for lifetime non -use, former, light, BRL, moderate and heavy use were : 3%/5%/2 3%/44%/19%/6% and 5%/2%/25%/44%/23 %/1% for UC and CD cases , respectively. There were no associations between any categories of alcohol consumption and risk of UC or CD in the una djusted and adjusted odds ratios . Conclusion There was no evidence of association s between alcohol use and the odds of developing either UC or CD