Comparative biomonitors of coastal trace metal contamination in tropical South America (N. Brazil)

Samples of 5 bivalve molluscs (Crassostrea rhizophorae, Mytella charruana, Anomalocardia brasiliana, Anadara ovalis, Phacoides pectinata), 2 barnacles (Fistulobalanus citerosum, Balanus amphitrite) and leaves of the mangrove tree Rhizophora mangle were collected from up to 11 sites in two estuaries in Natal, Brazil--the comparatively contaminated Potengi estuary and the comparatively uncontaminated Curimataú estuary. Specimens were analysed for the trace metals Zn, Cu, Cd, Fe, Mn and Ni, and a comparative assessment made of the power of the different species as trace metal biomonitors. Four of the 5 bivalves (not P. pectinata) take up metals from solution and suspended material (food source), while P. pectinata as a lucinid with symbiotic chemosynthetic bacteria takes up metals from dissolved sources only. The organisms with the strongest net accumulation of particular metals showed the greatest discrimination between trace metal bioavailabilities between sites. Barnacles (F. citerosum) showed the best discrimination, but oysters (C. rhizophorae) are particularly recommended as biomonitors given their strong accumulation patterns for many trace metals, their large size and their local abundance.     

An initial evaluation of drone‐based monitoring of boulder beaches in Galicia,north‐western Spain

Low altitude flights by a micro‐drone were made in 2012 and 2013 over two boulder beaches in north‐western Spain. Geographical information system software was used to map the data. Boulder outlines from the first flight were recorded on 4796 clasts at Laxe Brava and 2508 clasts at Oia. Changes in location were identified by overlaying these outlines on the 2013 images. About 17.5% of the boulders (mean surface area 0.32 m²) moved at Laxe Brava and about 53% (mean surface area 0.23 m²) at Oia. Most movement on both beaches was between the mid‐tide to about 2 m above the high tidal level. The location and elevation of the highest points were also recorded on the 2012 images on 4093 boulders at Laxe Brava and 3324 boulders at Oia. These elevations were compared with the elevations at the same locations in 2013. The occurrence and scale of the elevational changes were generally consistent with changes in the boulder outlines. The study confirmed that boulder beaches can be cheaply and effectively monitored using high resolution, micro‐drone technology. Copyright © 2014 John Wiley & Sons, Ltd.     

MASTER: A multiple aspect view on trajectories

For many years trajectory data have been treated as sequences of space‐time points or stops and moves. However, with the explosion of the Internet of Things and the flood of big data generated on the Internet, such as weather channels and social network interactions, which can be used to enrich mobility data, trajectories become more and more complex, with multiple and heterogeneous data dimensions. The main challenge is how to integrate all this information with trajectories. In this article we introduce a new concept of trajectory, called multiple aspect trajectory, propose a robust conceptual and logical data model that supports a vast range of applications, and, differently from state‐of‐the‐art methods, we propose a storage solution for efficient multiple aspect trajectory queries. The main strength of our data model is the combination of simplicity and expressive power to represent heterogeneous aspects, ranging from simple labels to complex objects. We evaluate the proposed model in a tourism scenario and compare its query performance against the state‐of‐the‐art spatio‐temporal database SECONDO extension for symbolic trajectories.     

Orbital structure of self-consistent cuspy triaxial stellar systems

We used a multipolar code to create, through dissipationless collapses of systems of 10⁶ particles, two cuspy self-consistent triaxial stellar systems with γ ≈ 1. One of the systems has an axial ratio similar to that of an E4 galaxy and it is only mildly triaxial (T = 0.914), while the other one is strongly triaxial (T = 0.593) and its axial ratio lies in between those of Hubble types E5 and E6. Both models rotate although their total angular momenta are zero, i.e., they exhibit figure rotation. The angular velocity is very small for the less triaxial model and, while it is larger for the more triaxial one, it is still comparable to that found by Muzzio (Celest Mech Dynam Astron 96(2):85–97, 2006) to affect only slightly the dynamics of a similar model. Except for minor evolution, probably caused by unavoidable relaxation effects of the N-body code, the systems are highly stable. The potential of each system was subsequently approximated with interpolating formulae yielding smooth potentials, stationary in frames that rotate with the models. The Lyapunov exponents could then be computed for randomly selected samples of the bodies that make up the two systems, allowing the recognition of regular and of partially and fully chaotic orbits. Finally, the regular orbits were Fourier analyzed and classified using their locations on the frequency map. Most of the orbits are chaotic, and by a wide margin: less than 30% of the orbits are regular in our most triaxial model. Regular orbits are dominated by tubes, long axis ones in the less triaxial model and short axis tubes in the more triaxial one. Most of the boxes are resonant (i.e., they are boxlets), as could be expected from cuspy systems.     

Formulation of a tropical town energy budget (t-TEB) scheme

This work describes the tropical town energy budget (t-TEB) scheme addressed to simulate the diurnal occurrence of the urban heat island (UHI) as observed in the Metropolitan Area of Rio de Janeiro (MARJ; ?22° S; ?44° W) in Brazil. Reasoning about the tropical urban climate have guided the scheme implementation, starting from the original equations from Masson (Bound-Lay Meteorol 94:357–397, 2000). The modifications include (a) local scaling approaches for obtaining flux–gradient relationships in the roughness sub-layer, (b) the Monin-Obukhov similarity framework in the inertial sub-layer, (c) increasing aerodynamic conductance toward more unstable conditions, and (d) a modified urban subsurface drainage system to transfer the intercepted rainwater by roofs to the roads. Simulations along 2007 for the MARJ are obtained and compared with the climatology. The t-TEB simulation is consistent with the observations, suggesting that the timing and dynamics of the UHI in tropical cities could vary significantly from the familiar patterns observed in mid-latitude cities—with the peak heat island intensity occurring in the morning than at night. The simulations are suggesting that the thermal phase shift of this tropical diurnal UHI is a response of the surface energy budget to the large amount of solar radiation, intense evapotranspiration, and thermal response of the vegetated surfaces over a very humid soil layer.     

Correction to: Spatiotemporal variability of vegetation due to drought dynamics (2012–2017): a case study of the Upper Paraíba River basin,Brazil

Natural Hazards - This correction stands to support the updating of the original article for changing the name Glauciene Justino Ferreira to Glauciene Justino Ferreira da Silva. The author group...     

Pitfalls in Th–U dating of young Quaternary volcanic rocks: : a case study from Fornicher Kopf (East Eifel Volcanic Field, Germany)

The eruption age of the Fornicher Kopf basanite lava flow (East Eifel Volcanic Field, Germany) is of interest because it can provide an age constraint for part of the Quaternary Rhine river terrace chronology. Previous dating efforts by K–Ar and α-counting ²³⁰Th–²³⁸U methods produced a wide dispersion of ages. This paper presents a fresh attempt to date this lava flow by the potentially more precise mass spectrometric ²³⁰Th–²³⁸U mineral isochron technique. Unfortunately, this study also proved unsuccessful because it did not produce a meaningful mineral isochron: the only age information is provided by the fact that the groundmass shows ²³⁰Th–²³⁸U disequilibrium, which implies that the eruption age was <350 ka. However, the mineral data clearly highlight some of the problems that can plague efforts to date young lavas by the ²³⁰Th–²³⁸U method: (i) inherited older crystals; magnetite and pyroxene plot on the equiline (i.e. ²³⁰Th and ²³⁸U in secular equilibrium) and tielines to the groundmass data produce impossible ages, indicating that these crystals are older than the host magma, and (ii) open system behaviour; phlogopite has experienced variable, recent U exchange, which has implications for the reliability of this phase for alpha-recoil dating.     

Aspects of Mechanical Behavior and Modeling of a Tropical Unsaturated Soil

The research studies the applicability of two elastoplastic models for the collapse prediction of the lateritic soil profile from Southeastern Brazil. These tropical soils have peculiar geotechnical behavior, due to their mineralogical composition and porous structure coming from intense process of formation. Two elastoplastic models were analyzed: the Barcelona Basic Model (BBM) and another one based on BBM, however developed for tropical soils. Oedometric tests with suction control were performed at three distinct depths of the soil profile. The BBM was not suitable for the upper layer of the soil profile, because BBM considers the compressible behavior of the soil in function of the reduction of the elastoplastic compressibility index with the increase of the matric suction. The model developed for tropical soils showed better suited to the compressible behavior of the soil profile, resulting in good prediction of the collapse potential, mainly by accepting increasing values of the elastoplastic compressibility index of the soil profile with the matric suction rise.