Crystal Structure of the ZrO Phase at Zirconium/Zirconium Oxide Interfaces

Zirconium-based alloys are used in water-cooled nuclear reactors for both nuclear fuel cladding and structural components. Under this harsh environment, the main factor limiting the service life of zirconium cladding, and hence fuel burn-up efficiency, is water corrosion. This oxidation process has recently been linked to the presence of a sub-oxide phase with well-defined composition but unknown structure at the metal–oxide interface. In this paper, the combination of first-principles materials modeling and high-resolution electron microscopy is used to identify the structure of this sub-oxide phase, bringing us a step closer to developing strategies to mitigate aqueous oxidation in Zr alloys and prolong the operational lifetime of commercial fuel cladding alloys

An Open-Label Pilot Study Testing the Feasibility of Assessing Total Symptom Burden in Trials of Cannabinoid Medications in Palliative Care.

Background: There is considerable interest in the use of cannabinoids for symptom control in palliative care, but there is little high-quality evidence to guide clinical practice. Objectives: Assess the feasibility of using global symptom burden measures to assess response to medicinal cannabis, to determine median tolerated doses of cannabidiol (CBD) and tetrahydrocannabinol (THC), and to document adverse events (AEs). Design: Prospective two-arm open-label pilot trial of escalating doses of CBD and THC oil. Setting/Subjects: Participants had advanced cancer and cancer-related symptoms in a palliative and supportive care service in an Australian cancer center. Measurements: The main outcome measures were the number of participants screened and randomized over the time frame, the number of participants completing days 14 and 28 and providing total symptom distress scores (TSDSs) (measured using the Edmonton Symptom Assessment Scale), and the change from baseline of the TSDS at day 14. Results: Of the 21 participants enrolled (CBD, n = 16; THC, n = 5), 18 (86%) completed the primary outcome measure at day 14 and 8 completed at day 28. The median maximum tolerated doses were CBD, 300 mg/day (range 100-600 mg); THC, 10 mg/day (range 5-30 mg). Nine of 21 patients (43%) met the definition of response (≥6 point reduction in TSDS). Drowsiness was the most common AE. Conclusions: Trials of medicinal cannabis in advanced cancer patients undergoing palliative care are feasible. The doses of THC and CBD used in this study were generally well tolerated and the outcome measure of total symptom distress is promising as a measure of overall symptom benefit. Trial registration: ACTRN12618001205224

Temporal and phylogenetic evolution of the sauropod dinosaur body plan

The colossal size and body plan of sauropod dinosaurs are unparalleled in terrestrial vertebrates. However, to date, there have been only limited attempts to examine temporal and phylogenetic patterns in the sauropod bauplan. Here, we combine three-dimensional computational models with phylogenetic reconstructions to quantify the evolution of whole-body shape and body segment properties across the sauropod radiation. Limitations associated with the absence of soft tissue preservation in fossils result in large error bars about mean absolute body shape predictions. However, applying any consistent skeleton : body volume ratio to all taxa does yield changes in body shape that appear concurrent with major macroevolutionary events in sauropod history. A caudad shift in centre-of-mass (CoM) in Middle Triassic Saurischia, associated with the evolution of bipedalism in various dinosaur lineages, was reversed in Late Triassic sauropodomorphs. A craniad CoM shift coincided with the evolution of quadrupedalism in the Late Triassic, followed by a more striking craniad shift in Late Jurassic–Cretaceous titanosauriforms, which included the largest sauropods. These craniad CoM shifts are strongly correlated with neck enlargement, a key innovation in sauropod evolution and pivotal to their gigantism. By creating a much larger feeding envelope, neck elongation is thought to have increased feeding efficiency and opened up trophic niches that were inaccessible to other herbivores. However, we find that relative neck size and CoM position are not strongly correlated with inferred feeding habits. Instead the craniad CoM positions of titanosauriforms appear closely linked with locomotion and environmental distributions, potentially contributing to the continued success of this group until the end-Cretaceous, with all other sauropods having gone extinct by the early Late Cretaceous

Temperate southern Australian coastal waters are characterised by surprisingly high rates of nitrogen fixation and diversity of diazotrophs

Biological dinitrogen (N2) fixation is one mechanism by which specific microorganisms (diazotrophs) can ameliorate nitrogen (N) limitation. Historically, rates of N2 fixation were believed to be limited outside of the low nutrient tropical and subtropical open ocean; however, emerging evidence suggests that N2 fixation is also a significant process within temperate coastal waters. Using a combination of amplicon sequencing, targeting the nitrogenase reductase gene (nifH), quantitative nifH PCR, and 15N2 stable isotope tracer experiments, we investigated spatial patterns of diazotroph assemblage structure and N2 fixation rates within the temperate coastal waters of southern Australia during Austral autumn and summer. Relative to previous studies in open ocean environments, including tropical northern Australia, and tropical and temperate estuaries, our results indicate that high rates of N2 fixation (10–64 nmol L−1 d−1) can occur within the large inverse estuary Spencer Gulf, while comparatively low rates of N2 fixation (2 nmol L−1 d−1) were observed in the adjacent continental shelf waters. Across the dataset, low concentrations of NO3/NO2 were significantly correlated with the highest N2 fixation rates, suggesting that N2 fixation could be an important source of new N in the region as dissolved inorganic N concentrations are typically limiting. Overall, the underlying diazotrophic community was dominated by nifH sequences from Cluster 1 unicellular cyanobacteria of the UCYN-A clade, as well as non-cyanobacterial diazotrophs related to Pseudomonas stutzeri, and Cluster 3 sulfate-reducing deltaproteobacteria. Diazotroph community composition was significantly influenced by salinity and SiO4 concentrations, reflecting the transition from UCYN-A-dominated assemblages in the continental shelf waters, to Cluster 3-dominated assemblages in the hypersaline waters of the inverse estuary. Diverse, transitional diazotrophic communities, comprised of a mixture of UCYN-A and putative heterotrophic bacteria, were observed at the mouth and southern edge of Spencer Gulf, where the highest N2 fixation rates were observed. In contrast to observations in other environments, no seasonal patterns in N2 fixation rates and diazotroph community structure were apparent. Collectively, our findings are consistent with the emerging view that N2 fixation within temperate coastal waters is a previously overlooked dynamic and potentially important component of the marine N cycle

Analyticity and criticality results for the eigenvalues of the biharmonic operator

We consider the eigenvalues of the biharmonic operator subject to several homogeneous boundary conditions (Dirichlet, Neumann, Navier, Steklov). We show that simple eigenvalues and elementary symmetric functions of multiple eigenvalues are real analytic, and provide Hadamard-type formulas for the corresponding shape derivatives. After recalling the known results in shape optimization, we prove that balls are always critical domains under volume constraint.Comment: To appear on the proceedings of the conference "Geometric Properties for Parabolic and Elliptic PDE's - 4th Italian-Japanese Workshop" held in Palinuro (Italy), May 25-29, 201

Hydrochimie et potabilité des eaux du bassin versant du Nchi dans le plateau Bamoun (Ouest Cameroun)

Comme dans la plupart des métropoles camerounaises, l’Approvisionnement en Eau Potable (AEP) dans le périmètre urbain de Foumban reste un défi majeur pour les populations. L’objectif de ce travail est de comprendre la dynamique hydrochimique et le niveau de vulnérabilité des eaux de cette zone située dans le bassin versant du Nchi, plateau Bamoun, à l’Ouest du Cameroun. La méthodologie mise en oeuvre a consisté d’une part au suivi des paramètres physico-chimiques dans les eaux du cours d’eau Nchi et les eaux de nappes et d’autre part, à la caractérisation des paramètres bactériologiques dans les eaux souterraines sélectionnées en fonction de leur répartition spatiale et de leur sollicitation par les populations. Les résultats montrent que ces eaux sont acides à neutres (5.3 ≤ pH ≤ 7,7) et faiblement minéralisées [(15 μS/cm < C.E < 164,9 μS/cm) et (184 μeq/l ≤ TZ+ ≤ 1565 μeq/l)]. La concentration moyenne de la silice pondérée par les débits est de 23,55 mg/l et représente 59,33% de la somme de matières dissoutes minérales (TDS) qui est de 39,68 mg/l. L’ordre de grandeur décroissant des éléments majeurs dans les eaux du bassin versant du Nchi est le suivant : HCO- 3 > Ca2+ > Mg2+ >Na+ > K+ > NO3 - ≥ Cl- traduisant ainsi des eaux bicarbonatées calci-magnésiennes. Les variations spatiales des différentes espèces chimiques montrent de fortes concentrations dans les eaux de nappe par rapport aux eaux d’écoulement. Les analyses statistiques, les variations temporelles des minéraux dissouts et des fortes corrélations inter-élémentaires observées traduisent de leur origine commune qui est surtout l’altération chimique. L’analyse bactériologique met en évidence l’absence des streptocoques fécaux (SF) dans les puits P1 et P4 et la présence remarquée des coliformes fécaux (CF) qui sont de 30 UFC/100 ml, 20 UFC/100 ml et 36 UFC/100 ml respectivement dans les puits P1, P4 et la source S1. La présence de ces bactéries thermo-tolérantes, de même que les nitrates fortement représentés dans les eaux souterraines de la ville de Foumban montrent que ces eaux présentent une dégradation liée aux activités humaines.© 2015 International Formulae Group. All rights reserved.Mots clés: Lithologie, anthropisation, qualité de l’eau, altération chimique, bassin versant du Nchi, plateau BamounEnglish AbstractAs it is the case in most of Cameroonian towns, the Water Supply (WS) in the Foumban urban area remains a major challenge to its inhabitants. The objective of this work is to understand the hydrochemical dynamics and the vulnerability of the water of this area located in the Nchi watershed, Bamoun plateau, West Cameroon. The methodology firstly consisted in the monitoring of physico-chemical parameters in the river Nchi and the underground water. Secondly, in the characterization of bacteriological parameters in underground water selected according to their spatial distribution and types frequently used by the population (wells, springs). The results show that the water is acidic to neutral (5.3 ≤ pH ≤ 7.7) and weakly mineralized [(15 μS/cm <EC <164.9 μS/cm) and (184 μeq/l ≤ + ≤ TZ 1565 μeq/l)]. The average concentration of weighted silica by the discharge rate is 23.55 mg/l, representing 59.33% of the sum of total dissolved solids (TDS) which is 39.68 mg/l. The decreasing order of magnitude of the major elements in the water of the Nchi watershed is: HCO- 3 > Ca2+ > Mg2+ >Na+ > K+ > NO3 - ≥ Cl- thus reflecting a calco-Mg-bicarbonate water. The spatial variations of different chemical elements show high concentrations in underground water as compared to surface flow. Statistical analysis, temporal variations of dissolved minerals and strong inter-element correlations indicate that they have a common origin, mainly resulting from chemical weathering. Bacteriological analysis shows the absence of faecal streptococci (SF) in the P1 and P4 wells and the significant presence of faecal coliforms (FC) which is 30 CFU/100 ml 20 CFU/100 ml and 36 CFU/100 ml respectively in the P1, P4 well and the S1 spring. The presence of these heat-tolerant bacteria, as well as nitrates strongly represented in groundwater of the Foumban town, shows that the water is polluted as a result human activities.Keywords: Lithology, anthropic activities, water quality, chemical weathering, Nchi watershed, Bamoun platea

Calcitization of aragonitic bryozoans in Cenozoic tropical carbonates from East Kalimantan, Indonesia

© The Author(s) 2016. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The file attached is the published version of the article

Inert gas clearance from tissue by co-currently and counter-currently arranged microvessels

To elucidate the clearance of dissolved inert gas from tissues, we have developed numerical models of gas transport in a cylindrical block of tissue supplied by one or two capillaries. With two capillaries, attention is given to the effects of co-current and counter-current flow on tissue gas clearance. Clearance by counter-current flow is compared with clearance by a single capillary or by two co-currently arranged capillaries. Effects of the blood velocity, solubility, and diffusivity of the gas in the tissue are investigated using parameters with physiological values. It is found that under the conditions investigated, almost identical clearances are achieved by a single capillary as by a co-current pair when the total flow per tissue volume in each unit is the same (i.e., flow velocity in the single capillary is twice that in each co-current vessel). For both co-current and counter-current arrangements, approximate linear relations exist between the tissue gas clearance rate and tissue blood perfusion rate. However, the counter-current arrangement of capillaries results in less-efficient clearance of the inert gas from tissues. Furthermore, this difference in efficiency increases at higher blood flow rates. At a given blood flow, the simple conduction-capacitance model, which has been used to estimate tissue blood perfusion rate from inert gas clearance, underestimates gas clearance rates predicted by the numerical models for single vessel or for two vessels with co-current flow. This difference is accounted for in discussion, which also considers the choice of parameters and possible effects of microvascular architecture on the interpretation of tissue inert gas clearance