Barium isotopes reveal role of ocean circulation on barium cycling in the Atlantic

We diagnose the relative influences of local-scale biogeochemical cycling and regional-scale ocean circulation on Atlantic barium cycling by analysing four new depth profiles of dissolved Ba concentrations and isotope compositions from the South and tropical North Atlantic. These new profiles exhibit systematic vertical, zonal and meridional variations that reflect the influence of both local-scale barite cycling and large-scale ocean circulation. Epipelagic decoupling of dissolved Ba and Si reported previously in the tropics is also found to be associated with significant Ba isotope heterogeneity. As such, we contend that this decoupling originates from the depth segregation of opal and barite formation but is exacerbated by weak vertical mixing. Zonal influence from isotopically-‘heavy’ water masses in the western North Atlantic evidence the advective inflow of Ba-depleted Upper Labrador Sea Water, which is not seen in the eastern basin or the South Atlantic. Meridional variations in Atlantic Ba isotope systematics below 2000 m appear entirely controlled by conservative mixing. Using an inverse isotopic mixing model, we calculate the Ba isotope composition of the Ba-poor northern end-member as +0.45 ‰ and the Ba-rich southern end-member +0.26 ‰, relative to NIST SRM 3104a. The near-conservative behaviour of Ba below 2000 m indicates that Ba isotopes can serve as an independent tracer of the provenance of northern- versus southern-sourced water masses in the deep Atlantic Ocean. This finding may prove useful in palaeoceanographic studies, should appropriate sedimentary archives be identified, and offers new insights into the processes that cycle Ba in seawater

Nitrogen partitioning, energy use efficiency and isotopic fractionation measurements from cows differing in genetic merit fed low-quality pasture in late lactation

The study was carried out to evaluate energy and nitrogen (N) use efficiencies of high and low breeding worth (BW) cow groups relative to N isotopic fractionation (∆¹⁵N). Eight high- and eight low-BW cows (mean BW index ≤ 198 and 57, respectively) in late lactation were used to conduct an N balance study with all cows fed autumn pasture. Individual cow pasture DM intake, N intake and N outputs of milk, urine and faeces were quantified. Plasma sample from each cow was harvested. Feed, plasma, faeces, urine and milk samples were measured for δ¹⁵N and calculated for ∆¹⁵N. Urea N in milk and plasma, and urinary excretion of purine derivatives were also measured. The metabolisable energy (ME) intake, milk energy output, and energy and N use efficiencies of high-BW cows were greater on average than low-BW cows. Conversely, the ratios of urinary N excretion to faecal N excretion and urinary N excretion to N intake were greater for low-BW cows than high-BW cows. There was no effect of BW groups on manure N output, apparent N digestibility, retained N, purine derivatives excretion or ratio of purine derivatives excretion to ME intake. No relationships were found between N and energy efficiencies and δ¹⁵N measurements. Regression analysis with individual cow measurement showed plasma δ¹⁵N - feed δ¹⁵N was negatively correlated with DM intake. N use efficiency was positively correlated with BW. High genetic merit cows are more efficient in N and energy use than lower genetic merit cows when fed low quality pasture in late lactation. Plasma δ¹⁵N - feed δ¹⁵N was proved to be a potential indicator of DM intake for individual cows when identical feed was offered. BW may be used to predict N use efficiency for individual cows. © CSIRO 2014

Modelling ground vibrations induced by harmonic loads

A finite-element model combining the frequency domain thin-layer method with paraxial boundary conditions to simulate the semi-infinite extent of a soil medium is presented in this paper. The combined numerical model is used to deal with harmonic vibrations of surface rigid foundations on non-horizontal soil profiles. The model can deal with soil media over rigid bedrock or significant depths of half-space. Structured finite elements are used to mesh simple geometry soil domains, whereas unstructured triangular mesh grids are employed to deal with complex geometry problems. Dynamic responses of homogeneous as well as layered soil profiles are simulated and validated against analytical and approximate solutions. Finally, the model is used to deal with surface ground vibration reduction, in which it is first validated against published results and then followed by an example involving a bridge

Extreme rainfall events alter the trophic structure in bromeliad tanks across the Neotropics

Changes in global and regional precipitation regimes are among the most pervasive components of climate change. Intensification of rainfall cycles, ranging from frequent downpours to severe droughts, could cause widespread, but largely unknown, alterations to trophic structure and ecosystem function. We conducted multi-site coordinated experiments to show how variation in the quantity and evenness of rainfall modulates trophic structure in 210 natural freshwater microcosms (tank bromeliads) across Central and South America (18°N to 29°S). The biomass of smaller organisms (detritivores) was higher under more stable hydrological conditions. Conversely, the biomass of predators was highest when rainfall was uneven, resulting in top-heavy biomass pyramids. These results illustrate how extremes of precipitation, resulting in localized droughts or flooding, can erode the base of freshwater food webs, with negative implications for the stability of trophic dynamics

Genome Wide Transcriptome Analysis of Dendritic Cells Identifies Genes with Altered Expression in Psoriasis

Activation of dendritic cells by different pathogens induces the secretion of proinflammatory mediators resulting in local inflammation. Importantly, innate immunity must be properly controlled, as its continuous activation leads to the development of chronic inflammatory diseases such as psoriasis. Lipopolysaccharide (LPS) or peptidoglycan (PGN) induced tolerance, a phenomenon of transient unresponsiveness of cells to repeated or prolonged stimulation, proved valuable model for the study of chronic inflammation. Thus, the aim of this study was the identification of the transcriptional diversity of primary human immature dendritic cells (iDCs) upon PGN induced tolerance. Using SAGESeq approach, a tag-based transcriptome sequencing method, we investigated gene expression changes of primary human iDCs upon stimulation or restimulation with Staphylococcus aureus derived PGN, a widely used TLR2 ligand. Based on the expression pattern of the altered genes, we identified non-tolerizeable and tolerizeable genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (Kegg) analysis showed marked enrichment of immune-, cell cycle- and apoptosis related genes. In parallel to the marked induction of proinflammatory mediators, negative feedback regulators of innate immunity, such as TNFAIP3, TNFAIP8, Tyro3 and Mer are markedly downregulated in tolerant cells. We also demonstrate, that the expression pattern of TNFAIP3 and TNFAIP8 is altered in both lesional, and non-lesional skin of psoriatic patients. Finally, we show that pretreatment of immature dendritic cells with anti-TNF-α inhibits the expression of IL-6 and CCL1 in tolerant iDCs and partially releases the suppression of TNFAIP8. Our findings suggest that after PGN stimulation/restimulation the host cell utilizes different mechanisms in order to maintain critical balance between inflammation and tolerance. Importantly, the transcriptome sequencing of stimulated/restimulated iDCs identified numerous genes with altered expression to date not associated with role in chronic inflammation, underlying the relevance of our in vitro model for further characterization of IFNprimed iDCs

Gravitational Waves from Gravitational Collapse

Gravitational wave emission from the gravitational collapse of massive stars has been studied for more than three decades. Current state of the art numerical investigations of collapse include those that use progenitors with realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non--axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with advanced ground--based and future space--based interferometric observatories.Comment: 68 pages including 13 figures; revised version accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

Long-term (trophic) purinergic signalling: purinoceptors control cell proliferation, differentiation and death

The purinergic signalling system, which uses purines and pyrimidines as chemical transmitters, and purinoceptors as effectors, is deeply rooted in evolution and development and is a pivotal factor in cell communication. The ATP and its derivatives function as a 'danger signal' in the most primitive forms of life. Purinoceptors are extraordinarily widely distributed in all cell types and tissues and they are involved in the regulation of an even more extraordinary number of biological processes. In addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion, there is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body. In this article, we focus on the latter in the immune/defence system, in stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption, as well as in cancer. Cell Death and Disease (2010) 1, e9; doi:10.1038/cddis.2009.11; published online 14 January 201

Ficaria verna Huds. extracts and their β-cyclodextrin supramolecular systems

<p>Abstract</p> <p>Background</p> <p>Obtaining new pharmaceutical materials with enhanced properties by using natural compounds and environment-friendly methods is a continuous goal for scientists. <it>Ficaria verna </it>Huds. is a widespread perennial plant with applications in the treat of haemorrhoids and to cure piles; it has also anti-inflammatory, astringent, and antibiotic properties. The goal of the present study is the obtaining and characterization of new <it>F. verna </it>extract/β-cyclodextrin complexes by using only natural compounds, solvents, and environment-friendly methods in order to increase the quality and acceptability versus toxicity indicator. Thus, the flavonoid content (as quercetin) of <it>Ficaria verna </it>Huds. flowers and leaves from the West side of Romania was determined and correlated with their antioxidant activity. Further, the possibility of obtaining β-cyclodextrin supramolecular systems was studied.</p> <p>Results</p> <p><it>F. verna </it>flowers and leaves extracts were obtained by semi-continuous solid-liquid extraction. The raw concentrated extract was spectrophotometrically analyzed in order to quantify the flavonoids from plant parts and to evaluate the antioxidant activity of these extracts. The <it>F. verna </it>extracts were used for obtaining β-cyclodextrin complexes; these were analyzed by scanning electron microscopy and Karl Fischer water titration; spectrophotometry was used in order to quantifying the flavonoids and evaluates the antioxidant activity. A higher concentration of flavonoids of 0.5% was determined in complexes obtained by crystallisation method, while only a half of this value was calculated for kneading method. The antioxidant activity of these complexes was correlated with the flavonoid content and this parameter reveals possible controlled release properties.</p> <p>Conclusions</p> <p>The flavonoid content of <it>F. verna </it>Huds. from the West side of Romania (Banat county) is approximately the same in flowers and leaves, being situated at a medium value among other studies. β-Cyclodextrin complexes of <it>F. verna </it>extracts are obtained with lower yields by crystallisation than kneading methods, but the flavonoids (as quercetin) are better encapsulated in the first case most probably due to the possibility to attain the <it>host</it>-<it>guest </it>equilibrium in the slower crystallisation process. <it>F. verna </it>extracts and their β-cyclodextrin complexes have antioxidant activity even at very low concentrations and could be used in proper and valuable pharmaceutical formulations with enhanced bioactivity.</p

Sensitivity to differences in the motor origin of drawings:from human to robot

This study explores the idea that an observer is sensitive to differences in the static traces of drawings that are due to differences in motor origin. In particular, our aim was to test if an observer is able to discriminate between drawings made by a robot and by a human in the case where the drawings contain salient kinematic cues for discrimination and in the case where the drawings only contain more subtle kinematic cues. We hypothesized that participants would be able to correctly attribute the drawing to a human or a robot origin when salient kinematic cues are present. In addition, our study shows that observers are also able to detect the producer behind the drawings in the absence of these salient kinematic cues. The design was such that in the absence of salient kinematic cues, the drawings are visually very similar, i.e. only differing in subtle kinematic differences. Observers thus had to rely on these subtle kinematic differences in the line trajectories between drawings. However, not only motor origin (human versus robot) but also motor style (natural versus mechanic) plays a role in attributing a drawing to the correct producer, because participants scored less high when the human hand draws in a relatively mechanical way. Overall, this study suggests that observers are sensitive to subtle kinematic differences between visually similar marks in drawings that have a different motor origin. We offer some possible interpretations inspired by the idea of "motor resonance''