Hydrocarbons in the water and sediment of wilderness lake II

Hydrocarbons are reported for another wilderness lake including polynuclear aromatics. All hydrocarbons appear to be of natural origin.     

REDD+ readiness process in Cameroon: an analysis of multi-stakeholder perspectives

Cameroon has been a keen participant in Reducing Emissions from Deforestation and Forest Degradation plus conservation, sustainable management of forests and enhancement of carbon stocks (REDD+) negotiations since 2005 and has engaged in activities to enhance the implementation of REDD+. This article reviews progress on REDD+ readiness in Cameroon based on a multiple REDD+ functions framework. Results show that some progress has been made in terms of planning and coordination, institutional development, and the development of some REDD+ projects. Absence of a legal framework, inadequate procedures for stakeholder participation, slow progress in the development of a national strategy, monitoring, reporting, and verification (MRV) challenges, and weak financing remain prominent constraints. Despite having one of the slowest REDD Readiness Preparation Proposal (R-PP) processes in the Congo Basin, stakeholders feel strong ownership because the R-PP was done almost entirely by Cameroonian experts. Some opportunities for improving REDD+ can be considered going forward, including the establishment of procedures for a broader participatory process, speeding up the operationalization of the National Observatory on Climate Change, making use of the ongoing forestry law reform, consideration of a carbon concessions concept, tapping from international initiatives to build on MRV, and improving benefit sharing and financing through the development of an appropriate and decentralized mechanism. Enhancing these opportunities is fundamental for successful REDD+ implementation in Cameroon.

Policy relevance

This article offers a new multidimensional approach to assessing the REDD+ readiness process in Cameroon. This critical assessment, which is done using six key functions, provides an opportunity for enhanced understanding of the process by policy makers, decision makers, and professionals with a view to enabling improvements in the readiness process. Furthermore, the article proffers a series of opportunities that the government and other relevant stakeholders can capitalize on to overcome current hurdles affecting the REDD+ readiness process. It is hoped that policy makers driving the REDD+ process in Cameroon will be able to incorporate the findings of this research into their strategic policy, formulated to advance the REDD+ readiness process. More importantly, it is hoped that the multidimensional framework applied in this study could be useful for assessing REDD+ in similar contexts in the Congo Basin.     

Reducing model complexity for explanation and prediction

Numerical models can be useful for explaining poorly understood phenomena or for reliable quantitative predictions. When modeling a multi-scale system, a ‘top-down’ approach—basing models on emergent variables and interactions, rather than explicitly on the much faster and smaller scale processes that give rise to them—facilitates both goals. Parameterizations representing emergent interactions range from highly simplified and abstracted to more quantitatively accurate. Empirically based large-scale parameterizations lead more reliably to accurate large-scale behavior than do parameterizations of much smaller scale processes. Conversely, purposefully simplified representations of model interactions can enhance a model's utility for explanation, clarifying the key feedbacks leading to an enigmatic behavior. For such potential insights to be relevant, the interactions in the model need to correspond to those in the ‘real’ system in some straightforward way. Such a correspondence usually holds for models constructed for predictive purposes, although this is not a requirement. The goals motivating a modeling endeavor help determine the most appropriate modeling strategies, as well as the most appropriate criteria for judging model usefulness.     

The vibrational characteristics of a twelve-storey steel frame building

The Ralph M. Parsons World Headquarters building, a twelve-storey steel frame structure, was subjected to a series of forced vibration tests. The natural frequencies, three-dimensional mode shapes and damping coefficients of nine modes of vibration were determined. Other features of this investigation included the study of non-linearities associated with increasing levels of response, detailed measurements of the deformation of the first floor and the ground surrounding the structure, and measurements of strain in one of the columns of the structure during forced excitation. The dynamic characteristics of the building determined by these tests are compared to those predicted by a finite element model of the structure. The properties of primarily translational modes are predicted reasonably well, but adequate prediction of torsional motions is not obtained. The comparison between measured and predicted strains suggests that estimates of stress determined from finite element analyses of buildings might be within 25 per cent of those experienced by the structure for a known excitation.     

A Challenging Solar Eruptive Event of 18 November 2003 and the Causes of the 20 November Geomagnetic Superstorm. III. Catastrophe of the Eruptive Filament at a Magnetic Null Point and Formation of an Opposite-Handedness CME

Our analysis in Papers I and II (Grechnev et al., Solar Phys. 289, 289, 2014b and Solar Phys. 289, 1279, 2014c) of the 18 November 2003 solar event responsible for the 20 November geomagnetic superstorm has revealed a complex chain of eruptions. In particular, the eruptive filament encountered a topological discontinuity located near the solar disk center at a height of about 100 Mm, bifurcated, and transformed into a large cloud, which did not leave the Sun. Concurrently, an additional CME presumably erupted close to the bifurcation region. The conjectures about the responsibility of this compact CME for the superstorm and its disconnection from the Sun are confirmed in Paper IV (Grechnev et al., Solar Phys. submitted, 2014a), which concludes about its probable spheromak-like structure. The present article confirms the presence of a magnetic null point near the bifurcation region and addresses the origin of the magnetic helicity of the interplanetary magnetic clouds and their connection to the Sun. We find that the orientation of a magnetic dipole constituted by dimmed regions with the opposite magnetic polarities away from the parent active region corresponded to the direction of the axial field in the magnetic cloud, while the pre-eruptive filament mismatched it. To combine all of the listed findings, we propose an intrinsically three-dimensional scheme, in which a spheromak-like eruption originates via the interaction of the initially unconnected magnetic fluxes of the eruptive filament and pre-existing ones in the corona. Through a chain of magnetic reconnections their positive mutual helicity was transformed into the self-helicity of the spheromak-like magnetic cloud.     

Orbital dynamics of three-dimensional bars – I. The backbone of three-dimensional bars. A fiducial case

In this series of papers we investigate the orbital structure of three-dimensional (3D) models representing barred galaxies. In the present introductory paper we use a fiducial case to describe all families of periodic orbits that may play a role in the morphology of three-dimensional bars. We show that, in a 3D bar, the backbone of the orbital structure is not just the x1 family, as in two-dimensional (2D) models, but a tree of 2D and 3D families bifurcating from x1. Besides the main tree we have also found another group of families of lesser importance around the radial 3:1 resonance. The families of this group bifurcate from x1 and influence the dynamics of the system only locally. We also find that 3D orbits elongated along the bar minor axis can be formed by bifurcations of the planar x2 family. They can support 3D bar-like structures along the minor axis of the main bar. Banana-like orbits around the stable Lagrangian points build a forest of 2D and 3D families as well. The importance of the 3D x1-tree families at the outer parts of the bar depends critically on whether they are introduced in the system as bifurcations in z or in   z˙   .     

Relationship between exchangeable cations and palaeosalinity

In Carboniferous shales a relationship has been found between exchangeable cations and palaeosalinity. In the marine shales the concentration of exchangeable Mg is higher than in shales deposited in fresh and brackish water, and the concentrations of exchangeable Ca, Na and K are lower. The same relationships have been observed in modern sediments. When the cation concentrations in the whole rock are compared with the exchangeable cation concentrations, incorporation into the sediment of K and possibly Mg in the marine environment is indicated. Furthermore, the loss of Ca and Na from the sediment can be accounted for by the loss from exchange sites. Reactions taking place during halmyrolysis would appear to be more important than those taking place during diagenesis.     

The selective replacement of the aluminum silicates by white mica

From considerations of relativeG-T surfaces inferred from publishedP-T data and the occurrence of replacement textures of Al₂SiO₅ polymorphs in rocks, the relative positions of curves representing the following equation in _K+ —T — pH ispace on substituting Al₂SiO₅ different polymorphs are derived.3 Al₂SiO₅ + 3 SiO₂ (quartz) + 2 K⁺ + 3 H₂O 2 KAl₂[AlSi₃O₁₀](OH)₂ (muscovite)+ 2 H⁺. The curves are different because of the differentG-T values for the polymorphs which, in the field, is borne out by the observation that in a rock containing two or three Al₂SiO₅ polymorphs, in nearly all instances only one polymorph is replaced by white mica. Instances of textural relations showing the interpreted selective replacement of one Al₂SiO₅ polymorph by a white mica in the presence of one (or two) other Al₂SiO₅ polymorph(s) are cited both from the literature and various field examples. The selective replacement of kyanite if sillimanite and/or andalusite is/are present, and of andalusite if only sillimanite is present are interpreted to show that generally during the muscovitization reaction, the field of sillimanite in the above reaction (left hand side) at a particular pH (H⁺ concentration) and is larger in _K+ —T space than that of andalusite which in turn is larger than that of kyanite. Theoretically it is shown that variations to this can exist but the field evidence suggests these only occur under rare geological conditions. Although this is not totally conclusive, the selectiveness of the replacement is interpreted to show that the fluid was buffered with respect to K⁺ and H⁺ on or near the curve of the polymorph showing the lowest stability field until that polymorph is totally consumed, after which the fluid composition moves to the next lowest curve for the remaining polymorph(s) present in the rock. The alteration of more than one polymorph by an apparently simultaneous process of alteration is rare and usually occurs at a low grade of metamorphism. This is interpreted to show that the buffering reaction could not keep pace with the influx of fluid and change the composition of this fluid (in most cases).     

A method for uncertainty constraint of catchment discharge and phosphorus load estimates

River discharge and nutrient measurements are subject to aleatory and epistemic uncertainties. In this study, we present a novel method for estimating these uncertainties in colocated discharge and phosphorus (P) measurements. The “voting point”‐based method constrains the derived stage‐discharge rating curve both on the fit to available gaugings and to the catchment water balance. This helps reduce the uncertainty beyond the range of available gaugings and during out of bank situations. In the example presented here, for the top 5% of flows, uncertainties are shown to be 139% using a traditional power law fit, compared with 40% when using our updated “voting point” method. Furthermore, the method is extended to in situ and lab analysed nutrient concentration data pairings, with lower uncertainties (81%) shown for high concentrations (top 5%) than when a traditional regression is applied (102%). Overall, for both discharge and nutrient data, the method presented goes some way to accounting for epistemic uncertainties associated with nonstationary physical characteristics of the monitoring site.