Hierarchical Bayes models for daily rainfall time series at multiple locations from heterogenous data sources

We estimate a Hierarchical Bayesian models for daily rainfall that incorporates two novelties for estimating spatial and temporal correlations. We estimate the within site time series correlations for a particular rainfall site using multiple data sources at a given location, and we estimate the across site covariance in rainfall based on location distance. Previous rainfall models have captured cross site correlations as a functions of site specific distances, but not within site correlations across multiple data sources, and not both aspects simultaneously. Further, we incorporate information on the technology used (satellite versus rain gauge) in our estimations, which is also a novel addition. This methodology has far reaching applications in providing more accurate and complex weather insurance contracts based combining information from multiple data sources from a single site, a crucial improvement in the face of climate change. Secondly, the modeling extends to many other data contexts where multiple datasources exist for a given event or variable where both within and between series covariances can be estimated over time

Index insurance and climate risk management: addressing social equity

Motivation Fair distribution of benefits from index insurance matters. Lack of attention to social equity can reinforce inequalities and undermine the potential index insurance holds as a tool for climate risk management that is also pro-poor. Purpose The aims are to: (i) examine social equity concerns raised by index insurance in the context of climate risk management; (ii) consider how greater attention can be given to social equity in index insurance initiatives; and (iii) reflect on the policy challenges raised by seeking to take social equity into account as a mechanism for climate risk reduction. Approach and methods The article draws on learning from the CGIAR’s Research Program on Climate Change, Agriculture and Food Security (CCAFS) and presents the cases of the Index Based Livelihoods Insurance (IBLI) and Agriculture and Climate Risk Enterprise Ltd. (ACRE) in East Africa. It proposes a framework for unpacking social equity related to equitable access, procedures, representation and distribution within index insurance schemes Findings Systematically addressing social equity raises hard policy choices for index insurance initiatives without straightforward solutions. Attention to how benefits and burdens of index insurance are distributed raises the unpalateable truth for development policy that the poorest members of rural society can be excluded. Nevertheless, a focus on social equity may open up opportunities to ensure index insurance is linked to more socially just climate risk management. At the very least, it may prevent index insurance from generating greater inequality. Taking social equity into account thus, shifts the focus from agricultural systems in transition per se to systems with potential to incorporate societal transformation through distributive justice. Policy implications A framework is presented for unpacking different dimensions of social equity in index insurance schemes. It is intended to facilitate identification of opportunities for building outcomes that are more equitable, with greater potential for inclusion and fairer distribution

Relations between assemblages of carpological remains and modern vegetation in a shallow reservoir in southern Poland

This paper explores relations between assemblages of carpological remains and vegetation in and around a small, shallow reservoir in southern Poland. The study was conducted from 2006 to 2008. Quantity and distribution of species in the reservoir were recorded annually during the growing season. In October 2008, 40 samples of surface sediment (top 2 cm) were collected along transects at 10 m intervals. Samples of 100 cm3 were prepared for analysis of plant macroremains. Assemblages of carpological remains generally reflect local vegetation well. In some cases, however, even analysis of numerous samples failed to fully capture the species composition or reflect plant ratios in the parent phytocenosis. Reasons for this include factors that affect seed production, transport and fossilization, which differ among species. Among the best-represented macroremains were plants of the rush phytocenosis. In analysed samples, macroremains of 68.8 % of extant rushes were identified. Sixty percent of submerged and floating-leaf taxa were found in carpological samples, whereas 26.7 % of the trees and bushes were represented in sediment deposits. Species composition of phytocenoses in the reservoir and in surrounding areas was best reflected by macroremains from the nearby reed bed. Numbers of diaspores of Mentha aquatica, Hippuris vulgaris and Carex reflected well their relative abundance in phytocenoses. Chara sp., Juncus inflexus and Eupatorium cannabinum were overrepresented, whereas Typha latifolia and Sparganium minimum were poorly represented in relation to contemporary plant cover. There were no diaspores of Phragmites australis, which dominates the contemporary reed bed. Besides the shape of a reservoir, the key factor influencing diaspore numbers is distribution of plant cover. In many cases, single diaspores (Potentilla erecta, Myosotis scorpioides, Lythrum salicaria, Scutellaria galericulata), or higher concentrations (Hippuris vulgaris, Mentha aquatica, Eleocharis palustris, Schoenoplectus tabernaemontani, Chara sp.) reflected well the location of parent vegetation. The findings indicate that carpological remains in sediments can be an important source of information about plants in and around lakes. They generally reflect well local vegetation and in some cases may be used to identify taxa that dominated in the past

On Predicting Mössbauer Parameters of Iron-Containing Molecules with Density-Functional Theory

The performance of six frequently used density functional theory (DFT) methods (RPBE, OLYP, TPSS, B3LYP, B3LYP*, and TPSSh) in the prediction of Mössbauer isomer shifts(δ) and quadrupole splittings (ΔEQ) is studied for an extended and diverse set of Fe complexes. In addition to the influence of the applied density functional and the type of the basis set, the effect of the environment of the molecule, approximated with the conducting-like screening solvation model (COSMO) on the computed Mössbauer parameters, is also investigated. For the isomer shifts the COSMO-B3LYP method is found to provide accurate δ values for all 66 investigated complexes, with a mean absolute error (MAE) of 0.05 mm s–1 and a maximum deviation of 0.12 mm s–1. Obtaining accurate ΔEQ values presents a bigger challenge; however, with the selection of an appropriate DFT method, a reasonable agreement can be achieved between experiment and theory. Identifying the various chemical classes of compounds that need different treatment allowed us to construct a recipe for ΔEQ calculations; the application of this approach yields a MAE of 0.12 mm s–1 (7% error) and a maximum deviation of 0.55 mm s–1 (17% error). This accuracy should be sufficient for most chemical problems that concern Fe complexes. Furthermore, the reliability of the DFT approach is verified by extending the investigation to chemically relevant case studies which include geometric isomerism, phase transitions induced by variations of the electronic structure (e.g., spin crossover and inversion of the orbital ground state), and the description of electronically degenerate triplet and quintet states. Finally, the immense and often unexploited potential of utilizing the sign of the ΔEQ in characterizing distortions or in identifying the appropriate electronic state at the assignment of the spectral lines is also shown

RUTHENIUM-99 MÖSSBAUER STUDY OF THE PEROVSKITE PHASES LaxSr1-xRuO3 AND LaxCa1-xRuO3

Les propriétés magnétiques, électroniques et structurales de solution solide LaxSr1-xRuO3 et LaxCa1-xRuO3 ont été étudiées par spectrométrie Mössbauer de 99Ru et par d'autres techniques. L'existence de phases LaxCa1-xRuO3 est démontrée pour la première fois à partir de diagrammes de poudre R. X. qui permettent de les identifier à des pérovskites distordues en structures orthorhombiques. Des mesures de résistivité électrique sur des poudres frittées montrent que toutes les phases sont métalliques avec ρ ≈ 10-3 ohm. cm. La substitution progressive de Sr2+ par La3+ dans le composé ferromagnétique SrRuO3 conduit à une rapide disparition du champ hyperfin à 4,2 K. Pour x = 0,25 certains ions Ru sont encore porteurs de moment, mais pour 0,4 ≤ x ≤ 0,75, on n'observe plus que des raies étroites de résonance, ce qui est caractéristique de la disparition du ferromagnétisme et la présence d'un état moyen d'oxydation de Ru dans chaque phase, soit Lax3+ Sr2+1-x Ru(4-x)+O3 plutôt que Lax3+Sr2+1-xRU3+x+Ru4+1-xO3 LaRuO3 et CaRuO3 donne essentiellement des spectres à une seule raie à 4,2 K, ce qui montre que le Ru dans les oxydes ne sont pas soumis à un ordre antiferromagnétique mais sont probablement paramagnétiques. Les solutions solides LaxCa1-xRuO3(0 < x ≤ 0,6) donnent une raie unique très étroite avec un déplacement isomérique qui varie progressivement depuis la valeur caractéristique de Ru4+ jusqu'à celle de Ru3+ (— 0,303 mm s-1 et — 0,557 mm s-1 par rapport à Ru métal), ce qui confirme bien l'existence d'états d'oxydation intermédiaires, également dans ces phases.The magnetic, electronic, and structural properties of the solid solutions LaxSr1-xRuO3 and LaxCa1-xRuO3 have been studied by 99Ru Mössbauer spectroscopy and other techniques. The LaxCa1-xRuO3 phases are reported for the first time and have been shown by powder X-ray diffraction measurements to be orthorhombically distorted perovskites. Electrical resistivity measurements on compacted powders show that all the phases are metallic with ρ ~ 10-3 ohm cm. Progressive substitution of Sr2+ by La3+ in ferromagnetic SrRuO3 leads to a rapid collapse of the magnetic hyperfine splitting at 4.2 K. For x = 0.25 some ruthenium ions still experience magnetic flux densities but for 0.4 ≤ x ≤ 0.75 only single, narrow resonance lines are observed, consistent both with the complete removal of the ferromagnetism and with the presence of an averaged ruthenium oxidation state in each phase, i. e. La3+xS2+1-x Ru(4-x)+O3 rather than La3+xSr2+1-xRu3+x Ru4+1-xO3. LaRuO3 and CaRuO3 both give essentially single-line spectra at 4.2 K, indicating that the ruthenium ions in these oxides are not involved in long-range antiferromagnetic order but are probably paramagnetic. The solid solutions LaxCa1-xRuO3 (0 < x ≤ 0.6) each give a sharp symmetrical singlet with a chemical isomer shift which moves progressively from the value characteristic of Ru4+ towards the value for Ru3+ (— 0.303 mm s-1 and — 0.557 mm s-1 respectively relative to Ru-metal), consistent with the presence of intermediate ruthenium oxidation States in these phases also. These results will be discussed together with those obtained recently on other related ruthenium oxide systems

Base- and Co(II)-catalyzed ring-opening reactions of perhydrooxireno[2,3-d][1,2]dioxines: An efficient route to 4-hydroxy-2,3-epoxy-ketones

A series of 3,4,6-substituted 3,6-dihydro-1,2-dioxines were epoxidized with m-chloroperbenzoic acid to furnish perhydrooxireno[2,3-d][1,2]dioxines (epoxy-1,2-dioxines) in yields ranging from 51% to 93% with de's from 26% to 100%. Unsymmetrical epoxy-1,2-dioxines were ring-opened using triethylamine to yield 4-hydroxy-2,3-epoxy-ketones quantitatively, and meso-epoxy-1,2-dioxines were ring-opened using Co(II) salen complexes to afford 4-hydroxy-2,3-epoxy-ketones in 77-98% yield. The first reported examples of the catalytic asymmetric ring-opening of meso-epoxy-1,2-dioxines using a range of chiral Co(II) salen and β-ketoiminato complexes to afford highly enantio-enriched 4-hydroxy-2,3-epoxy-ketones are also presented

A domino ring-opening/epoxidation of 1,2-dioxines

Copyright © 2004 American Chemical SocietyWhen allowed to react with alkaline hydrogen peroxide, monocyclic 1,2-dioxines ring-open to their isomeric -hydroxyenone intermediates which are rapidly epoxidized to afford trans-4-hydroxy-2,3-epoxyketones in 21-81% yield. In the case of meso-1,2-dioxines, Co(II) complex catalyzed asymmetric ring-opening of the 1,2-dioxine may be employed to furnish enantioenriched epoxide