High level sill and dyke intrusions initiated from rapidly buried mafic lava flows in scoria cones of Tongoa, Vanuatu (New Hebrides), South Pacific

Scoria cones are generally considered to grow rapidly in days to weeks or months. During their growth lava flows may be fed onto the cone surface from lava-lake breaches, or form by coalescence of spatter; such flows are preserved interbedded with scoria lapilli and ash beds. On Tongoa, an island of the Vanuatu volcanic arc in the South Pacific, a series of scoria cones developed during the Holocene, forming a widespread monogenetic volcanic field. Half sections of scoria cones along the coast expose complex interior architecture cone architectures. On the western side of Tongoa Island a scoria cone remnant with steeply crater-ward dipping beds of scoria ash and lapilli contains various dm-to-m thick lava flows, which are connected by irregular dikes cutting obliquely across the beds of the cone. The lava flows are coherent igneous bodies with well-developed flow top and basal breccias. The lavas interbedded with the cone-forming layers are part of a larger (up to 7 m thick) body that is connected to dykes and sills of irregular geometries that intrude the cone's pyroclastic layers. This 3D relationship suggests that the lava flows were buried quickly under the accumulating scoriaceous deposits. This allowed subsequent escape of magma from the fluid interiors of flows, with the magma then squeezed upward or laterally into the accumulating pyroclastic pile. Movement of the pile above the partly mobile lava, and potential destabilisation during intrusion into the pile of lava squeezed from the flows, may signal the onset of localised cone failures, and could be implicated in development of major cone breaches (e.g. Paricutin)

Compositional variation during monogenetic volcano growth and its implications for magma supply to continental volcanic fields

Individual volcanoes of continental monogenetic volcanic fields are generally presumed to erupt single magma batches during brief eruptions. Nevertheless, in two unrelated volcanic fields (the Waipiata volcanic field, New Zealand, and the Miocene-Pliocene volcanic field in western Hungary), we have identified pronounced and systematic compositional differences among products of individual volcanoes. We infer that this indicates a two-stage process of magma supply for these volcanoes. Each volcano records: (1) intrusion of a basanitic parent magma to lower- to mid-crustal levels and its subsequent fractionation to form a tephritic residual melt;, (2) subsequent transection of this reservoir by a second batch of basanitic melt, with tephrite rising to the surface at the head of the propagating basanite dyke. Eruption at the surface then yields initial tephrite, typically erupted as pyroclasts, followed by eruption and shallow intrusion of basanite from deeper in the dyke. By analogy with similar tephrite-basanite eruptions along rift zones of intraplate ocean-island volcanoes, we infer that fractionation to tephrite would have required decades to centuries. We conclude that the two studied continental monogenetic volcanic fields demonstrate a consistent history of early magmatic injections that fail to reach the surface, followed by capture and partial eruption of their evolved residues in the course of separate and significantly later injections of basanite that extend to the surface and erupt. This systematic behaviour probably reflects the difficulty of bringing small volumes of dense, primitive magma to the surface from mantle source regions. Ascent through continental crust is aided by the presence in the dyke head of buoyant tephrite captured during transection of the earlier-emplaced melt bodies

Non-stationarity in daily and sub-daily intense rainfall – Part 1: Sydney, Australia

This study was driven by a need to clarify how variations in climate might affect intense rainfall and the potential for flooding. Sub-daily durations are of particular interest for urban applications. Worldwide, few such observation-based studies exist, which is mainly due to limitations in data. While there are still large discrepancies between precipitation data sets from observations and models, both show that there is a tendency for moist regions to become wetter and for dry regions to become drier. However, changes in extreme conditions may show the opposite sign to those in average conditions. Where changes in observed intense precipitation have been studied, this has typically been for daily durations or longer. <br><br> The purpose of this two-part study is to examine daily and sub-daily rainfall extremes for evidence of non-stationarity. Here the problem was addressed by supplementing one long record (Part 1) by a set of shorter records for a 30-yr concurrent period (Part 2). Variations in frequency and magnitude of rainfall extremes across durations from 6 min to 72 h were assessed using data from sites in the south-east of Australia. For the analyses presented in this paper, a peaks-over-threshold approach was chosen since it allows investigating changes in frequency as well as magnitude. Non-parametric approaches were used to assess changes in frequency, magnitude, and quantile estimates as well as the statistical significance of changes for one station (Sydney Observatory Hill) for the period 1921 to 2005. Deviations from the long-term average vary with season, duration, and threshold. The effects of climate variations are most readily detected for the highest thresholds. Deviations from the long-term average tend to be larger for frequencies than for magnitudes, and changes in frequency and magnitude may have opposite signs. <br><br> Investigations presented in this paper show that variations in frequency and magnitude of events at daily durations are a poor indicator of changes at sub-daily durations. Studies like the one presented here should be undertaken for other regions to allow the identification of regions with significant increase/decrease in intense rainfall, whether there are common features with regards to duration and season exhibiting most significant changes (which in turn could lead to establishing a theoretical framework), and assist in validation of projections of rainfall extremes

After 'Black Saturday': adapting to bushfires in a changing climate

Abstract not availabl

Quantum chemical study of the hydrolysis of oxidized endogenous psychedelic N,N-dimethyltryptamine

The metabolism of biogenic N,N-dimethyltryptamine (DMT) starts with its enzymatic oxidation to indole-3-N,N-dimethylethaniminium cation (imDMT(+)) by monoamine oxidase (MAO). Following this reaction, a nonenzymatic hydrolysis occurs, yielding indole-3-acetaldehyde (IAL) and dimethylamine (DMA). In our in silico study, using a hybrid DFT method at the M06-2X/aug-cc-pVDZ level, we examined the necessity of explicit water molecules to accurately model the hydrolysis. Our calculations revealed that despite an implicit continuum solvent model, one or two explicit solvent molecules should be added to obtain meaningful activation barriers. Thus, we demonstrate that the hydrolysis can occur in a human cell without enzymatic assistance, paving the way for deeper understanding of DMT metabolism

EFFECT OF MC4R POLYMORPHISM ON PHYSIOLOGICAL STRESS RESPONSE IN PIGS

Melanocortin-4 receptor (MC4R) is a G-protein coupled receptor predominantly expressed in hypothalamic regions which are known for their roles in feeding behavior, energy homeostasis and HPA axis regulation. In this study, we analyzed the effect of a missense mutation (Asp298Asn) in the porcine MC4R gene on physiological stress response and carcass composition in pigs of two crosses: A (♀Duroc x ♂Swedish Landrace) x ♂Pietrain (n=25) and B (♀Swedish Landrace x ♂Large White) x ♂Pietrain (n=21). All pigs included in this study were heterozygous (Nn) for the stress syndrome gen. Blood samples were collected before loading and at exsanguinations to measure cortisol, lactate, glucose, serum enzymes activity and some haematological parameters. Because only one pig with AA genotype was observed, there was no indicated effect of this genotype on investigated parameters. The heterozygous (AG) pigs showed a lower increase (P<0.05) in CK and AST activity after exsanguinations as well as trend towards lower increase (P<0.10) in cortisol and lactate levels and higher increase (P<0.10) in RBC and haemoglobin content. Higher increase (P<0.05) in LDH activity was observed in GG homozygous pigs from group B, but not in pigs from group A. In addition, the heterozygous (AG) pigs had a higher backfat thickness and lower estimated lean (P<0.05) than homozygous (GG) pigs. These results may support a possible role of the MC4R Asp298Asn polymorphism in the genetic basis of stress response and economically important traits in pigs

Up-regulation of Tissue Factor in Human Pulmonary Artery Endothelial Cells after Ultrafine Particle Exposure

BACKGROUND: Epidemiology studies have linked exposure to pollutant particles to increased cardiovascular mortality and morbidity, but the mechanisms remain unknown. OBJECTIVES: We tested the hypothesis that the ultrafine fraction of ambient pollutant particles would cause endothelial cell dysfunction. METHODS: We profiled gene expression of human pulmonary artery endothelial cells (HPAEC) exposed to ultrafine particles (UFPs; 100 μg/mL) from Chapel Hill, North Carolina, or vehicle for 4 hr with Affymetrix HG U133 Plus 2.0 chips (n = 4 each). RESULTS: We found 320 up-regulated genes and 106 down-regulated genes (p < 0.01, 5% false discovery rate). We noted up-regulation of genes related to coagulation [tissue factor (F3) and coagulation factor II receptor-like 2 (F2RL2)] and differential regulation of genes related to F3 signaling (FOS, JUN, and NFKBIA). Results of quantitative polymerase chain reaction show a significant up-regulation of F3 after 10 and 100 μg/mL UFP exposures. Additionally, the water-soluble fractions of UFPs were sufficient to induce the expression of F3, F2RL2, and heme oxygenase 1 (HMOX1). Treatment of HPAEC with UFPs for 16 hr increased the release of interleukin (IL)-6 and IL-8. Pretreatment of HPAEC with a blocking antibody against F3 attenuated IL-6 and IL-8 release by 30 and 70%, respectively. CONCLUSIONS: Using gene profiling, we discovered that UFPs may induce vascular endothelial cells to express genes related to clotting. These results indicate that PM may cause adverse cardiovascular health effects by activating coagulation-inflammation circuitry

Metabolomic analysis of prostate cancer risk in a prospective cohort: The alpha‐tocolpherol, beta‐carotene cancer prevention (ATBC) study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113106/1/ijc29576.pd

A placebo-controlled, double-blind, randomized, multicenter study to assess the effects of dronedarone 400 mg twice daily for 12 weeks on atrial fibrillation burden in subjects with permanent pacemakers

Purpose Dronedarone is a benzofuran derivative with a pharmacological profile similar to amiodarone but has a more rapid onset of action and a much shorter half-life (13–19 h). Our goal was to evaluate the efficacy of dronedarone in atrial fibrillation (AF) patients using dual-chamber pacemakers capable of quantifying atrial fibrillation burden. Methods Pacemakers were adjusted to optimize AF detection. Patients with AF burden \u3e1 % were randomized to dronedarone 400 mg twice daily (BID) or placebo. Pacemakers were interrogated after 4 and 12 weeks of treatment. The primary endpoint was the change in AF burden from baseline over the 12-week treatment period. Patients with permanent AF, severe/recently decompensated heart failure, and current use of antiarrhythmic drugs were excluded. AF burden was assessed by a core laboratory blinded to treatment assignment. Results From 285 patients screened, 112 were randomized (mean age 76 years, 60 % male, 84 % hypertensive, 65 % with sick sinus syndrome, 26 % with diabetes mellitus type II, 15 % with heart failure). Baseline mean (SEM) AF burden was 8.77 % (0.16) for placebo and 10.14 % (0.17) for dronedarone. Over the 12-week study period, AF burden compared to baseline decreased by 54.4 % (0.22) (P = 0.0009) with dronedarone and trended higher by 12.8 % (0.16) (P = 0.450) with placebo. The absolute change in burden was decreased by 5.5 % in the dronedarone group and increased by 1.1 % in the placebo group. Heart rate during AF was reduced to approximately 4 beats/min with dronedarone (P = 0.285). Adverse events were higher with dronedarone compared to placebo (65 vs 56 %). Conclusions Dronedarone reduced pacemaker-assessed the relative AF burden compared to baseline and placebo by over 50 % during the 12-week observation period