Analytical Description of X-Ray Peaks: Application to L X-Ray Spectra Processing of Lanthanide Elements by Means of the Electron Probe Micro-Analyzer

The shape of Lα X-ray peaks analyzed by means of a LiF (200 plane) monochromator was described by a pseudo-Voigt function: P(λ) = 0.35 P1(λ)+ 0.65 P2(λ) where P1(λ) and P2(λ) are a Gaussian and a Lorentzian distribution centered at the same wavelength, with the same amplitude and half-width and in relative proportion 0.35 and 0.65 respectively. For peaks occurring at wavelength greater than ≃ 0.17 nm, a Gaussian offset was added in order to correct the asymmetry of peaks resulting from the monochromator mounting within the spectrometer. The effective wavelength resolution was obtained by quadrature addition of the instrumental resolution and the natural width of the X-ray peaks. It has been shown that the difference in peak width of the L emission peaks of the lanthanide elements resulted from their difference in their natural widths. For these elements, the Lβ2, Lγ1 and Lγ2 were found to be accompanied by non-diagram lines, Lβ14, Lγ9 and Lγ10 respectively. The wavelength separation distances Lβ14-Lβ2, Lγ9-Lγ1 and Lγ10-Lγ2 were found consistent with the distances derived from the plasmon theory

Structure and dynamics of Oxide Melts and Glasses : a view from multinuclear and high temperature NMR

Solid State Nuclear Magnetic Resonance (NMR) experiments allow characterizing the local structure and dynamics of oxide glasses and melts. Thanks to the development of new experiments, it now becomes possible to evidence not only the details of the coordination state of the network formers of glasses but also to characterize the nature of polyatomic molecular motifs extending over several chemical bonds. We present results involving 31P homonuclear experiments that allow description of groups of up to three phosphate units and 27Al/17O heteronuclear that allows evidencing μ3 oxygen bridges in aluminate glasses and rediscussion of the structure of high temperature melts.Comment: Journal of Non-Crystalline Solids (2007) in press; Also available online at: http://crmht.cnrs-orleans.fr/Intranet/Publications/?id=207

Seismic Response to Injection Well Stimulation in a High-Temperature, High-Permeability Reservoir

Fluid injection into the Earth's crust can induce seismic events that cause damage to local infrastructure but also offer valuable insight into seismogenesis. The factors that influence the magnitude, location, and number of induced events remain poorly understood but include injection flow rate and pressure as well as reservoir temperature and permeability. The relationship between injection parameters and injection-induced seismicity in high-temperature, high-permeability reservoirs has not been extensively studied. Here we focus on the Ngatamariki geothermal field in the central Taupō Volcanic Zone, New Zealand, where three stimulation/injection tests have occurred since 2012. We present a catalog of seismicity from 2012 to 2015 created using a matched-filter detection technique. We analyze the stress state in the reservoir during the injection tests from first motion-derived focal mechanisms, yielding an average direction of maximum horizontal compressive stress (SHmax) consistent with the regional NE-SW trend. However, there is significant variation in the direction of maximum compressive stress (σ1), which may reflect geological differences between wells. We use the ratio of injection flow rate to overpressure, referred to as injectivity index, as a proxy for near-well permeability and compare changes in injectivity index to spatiotemporal characteristics of seismicity accompanying each test. Observed increases in injectivity index are generally poorly correlated with seismicity, suggesting that the locations of microearthquakes are not coincident with the zone of stimulation (i.e., increased permeability). Our findings augment a growing body of work suggesting that aseismic opening or slip, rather than seismic shear, is the active process driving well stimulation in many environments

Isolation of bis-indole alkaloids with antileishmanial and antibacterial activities from Peschiera van heurkii (syn. Tabernaemontana van heurkii)

Des extraits de feuilles et d'écorces de tiges de #Peschiera van heurkii (Muell. Arg.) L. Allorge, (Syn. #Tabernaemontana van heurkii Muell. Arg.) ont montré une activité antileishmanienne et antibactérienne significative. Les activités étaient concentrées dans les fractions alcaloïdiques, desquelles ont été isolés et identifiés 20 alcaloïdes indoliques et bis-indoliques. La plus forte activité leishmanicide et antibactérienne fut observée avec les alcaloïdes dimères conodurine (1), N-démethyle - conodurine (=gabunine) et conoduramine. Les deux premiers composés se sont avérés faiblement toxiques vis-à-vis des cellules hôtes les macrophages, tout en présentant une forte toxicité pour les formes intracellulaires du parasite. #In vitro$, l'alcaloïde (1) s'est avéré moins actif que le médicament de référence, le glucantime (=N-methylglucamine antimonate). (Résumé d'auteur

Effects of regional and local stresses on fault slip tendency in the southern Taranaki Basin, New Zealand

© 2019 Elsevier Ltd Determining the potential for faults to slip is widely employed for evaluating fault slip potential and associated earthquake hazards, and characterising hydrocarbon seal integrity and reservoir properties. Here we use borehole and 3D seismic reflection data to estimate stress orientations and magnitudes, fault geometries and slip tendency in the southern Taranaki Basin, New Zealand. Late Cenozoic normal faults in the basin range in strike from E-W to NE-SW and are associated with stress changes from basin to borehole scales. The Maui and Maari-Manaia regions, part of the eastern mobile belt, show a strike-slip/normal stress regime (SHmax ≥ Sv > Shmin). The Tui region, part of the western stable platform, shows a normal stress regime (Sv > SHmax > Shmin). Both regions have a mean SHmax azimuth of ENE-WSW. Although the southern Taranaki basin is undergoing active deformation at plate tectonic scales, the stress magnitudes appear insufficiently high to reactivate the faults assuming a classic coefficient of friction. SHmax azimuths and SHmax:Sv magnitude ratios vary locally between boreholes and with depth. A borehole that intersects an inactive seismic-scale fault and borehole-scale faults over a 150-m interval shows SHmax to rotate by up to 30° proximal to the faults, which are favourably orientated for slip in both strike-slip and normal regimes. The small borehole-scale faults may, however, be active within the inactive seismic scale fault's damage zone. We highlight changes of slip tendency along faults resulting from local variations in the stress field and non-planar fault geometries that could not be resolved using only seismic reflection data and regional stress tensor. In the Taranaki Basin additional sub-seismic fault mapping, stress information and mechanical rock property testing are required to realise the potential of stress-based prediction of along-fault permeability and fluid migration

Tectonic Controls on Taupo Volcanic Zone Geothermal Expression: Insights From Te Mihi, Wairakei Geothermal Field

Information on structure, stress, and their interrelationship is essential for understanding structurally controlled geothermal permeability. Active fault mapping, borehole image analysis, and well testing in the Te Mihi geothermal area, New Zealand, allows us to refine structural and fluid flow architecture of this resource. The Te Mihi area is structurally complex, comprising a set of NW dipping master faults containing pervasive SE dipping antithetic and splay structures in their hanging walls. These faults are also intersected by E-W striking faults. A localized, N-S striking structural trend is also observed at Te Mihi. In consideration with Global Navigation Satellite System velocity vectors, both active NE-SW and E-W striking faults create biaxial extension at Te Mihi, though the observed NE-SW SHmax direction suggests that contemporary extension is NW-SE dominated. Stress field perturbations coincide with structural complexities like fault splays and intersections and/or proximity to recently active E-W and NE-SW striking structures. Borehole fluid flow at Te Mihi is concentrated at NW dipping master fault intersections, travel time fractures on acoustic image logs, halo fractures on resistivity image logs, NE-SW and E-W striking fractures, intervals of high fracture density, and spatial concentrations of wide aperture fractures and recently active NE-SW and E-W striking fractures. This study suggests Te Mihi geothermal expression results from biaxial extension evident from active structural trend intersections and the predominance of NE-SW and E-W striking structures within permeable well zones. Biaxial extension is therefore an important control on crustal fluid flow within the Taupo Volcanic Zone and thus geothermal resource delineation

Effective use of ecosystem and biological knowledge in fisheries

The general aim of the ECOKNOWS project is to improve the use of biological knowledge in fisheries science and management. The lack of appropriate calculus methods and fear of statistical overparameterisation has limited biological reality in fisheries models. This reduces biological credibility perceived by many stakeholders. We solve this technical estimation problem by using up-to date methodology supporting more effective use of data. The models suggested will include important knowledge about biological processes and the applied statistical inference methods allow to integrate and update this knowledge in stock assessment. We will use the basic biological data (such as growth, maturity, fecundity, maximum age and recruitment data sets) to estimate general probabilistic dependencies in fish stock assessments. In particular, we will seek to improve the use of large existing biological and environmental databases, published papers and survey data sets provided by EU data collection regulations and stored by ICES and EU member countries. Bayesian inference will form the methodological backbone of the project and will enable realistic estimations of uncertainty. We develop a computational learning approach that builds on the extensive information present in FishBase (www.fishbase.org).The developed methodology will be of fundamental importance, especially for the implementation of the Ecosystem Approach to Fisheries Management. It has been a difficult challenge even for target species with long data series, and now the same challenge is given for new and poorly studied species. We will improve ways to find generic and understandable biological reference points, such as the required number of spawning times per fish, which also supports the management needs in the developing countries. ECOKNOWS applies decision analysis and bioeconomic methods to evaluate the validity and utility of improved information, helping to plan efficient EU data collection.North Atlantic (NA) stock assessments address the marine phase, estimating returns to home waters, with Pre-Fishery Abundance (PFA) estimated through raising of national (or regional) annual catches by exploitation rates and attributing unreported catch and natural mortality ranges in Monte Carlo simulations. Baltic stocks in contrast, are estimated through integrated Bayesian life cycle state-space models including riverine and sea phases (Michielsens et al., 2008). There is presently no interaction between the two methodologies.We detail the two approaches specifying similarities in biology, as a prerequisite to their harmonization for parallel inference and risk analysis, independent of scales, available data and management objectives. Through aggregations of scale and availability, assimilations of data differ. For the Baltic much is performed within the forecasting framework, and while aggregations in the NA case are disparate, finer scale details are available. In the Baltic a scale of “river” is used as the geographical unit, while in the NA, 3 geo-regions are treated independently, each operating at arbitrary regional scales. To harmonize NA and Baltic approaches, a multi-scale integrated life cycle model in a Hierarchical Bayesian Modelling (HBM) framework is proposed for the NA to capture inherent complexities from mixing of life cycle age and stage cohorts, which is currently not addressed. A stage-structured life cycle approach is proposed, incorporating freshwater and marine phase variability of life histories (survival and life history choices) and auto-regenerated cohort dynamics. This represents a large change in both the modelling and statistical inference framework.Key structural hypotheses and common informative prior distributions for modelling demographic processes, for both NA and Baltic models are developed. Together with the Bayesian methodology these form the core of the harmonization process. To harmonize modelling of the demographic process the following items are necessary: State-space representation of all life stages including those not directly observed to explicitly separate out modeling of the demographic and observation processes, so as the harmonization of the models for the core ecological process can be thought independently from the data availability. Age/stage-based demographic models to integrate biological and ecological knowledge of population dynamics, characterized by seaward migrations of smolts and spawning migration of adults back to freshwater, accommodating intra- and inter-population variability in life history traits. Probabilistic demographic transitions and between-years variability of certain parameters to capture both environmental and demographic stochasticity. Variable egg to juvenile density-dependent average survival, of classical survival functions. Common approach to forecast yearly variations of marine post-smolts survival.Funer: FP7-KBBE European Commission CORDI