Precipitation of pyroxenes and Mg2SiO4 from majoritic garnet: simulation of peridotite exhumation from great depth

Our experimental simulations of the exhumation path of mantle peridotites show that high‐temperature (1400 °C) decompression of lherzolite from 14 to 13 and 12 GPa results in exsolution of interstitial blebs of diopside and Mg₂SiO₄ (wadsleyite) lamellae from majoritic garnet. At lower pressures (from 8 to 5 GPa, at T = 1400 °C) only enstatite exsolves as blebs at garnet boundaries. Continuous high‐temperature decompression from 14 to 7 GPa produces zoned majoritic garnet containing blebs of exsolved pyroxenes inside garnet rims. No intracrystalline precipitation of pyroxene was observed in garnet, although such lamellae are found in some natural garnet peridotites. The explanation appears to be the three orders of magnitude difference in grain size between experimental and natural specimens. Our data suggest that Mg₂SiO₄ and diopside exsolutions reflect the deepest point of the exhumation path of garnet peridotites, whereas enstatite precipitation may be restricted to garnets with less majoritic component at shallower depths.     

Identification and classification of galaxies using a biologically-inspired neutral network

Recognition/Classification of galaxies is an important issue in the large-scale study of the Universe; it is not a simple task. According to estimates computed from the Hubble Deep Field (HDF), astronomers predict that the universe may potentially contain over 100 billion galaxies. Several techniques have been reported for the classification of galaxies. Parallel developments in the field of neural networks have come to a stage that they can participate well in the recognition of objects. Recently, the Pulse-Coupled Neural Network (PCNN) has been shown to be useful for image pre-processing. In this paper, we present a novel way to identify optical galaxies by presenting the images of the galaxies to a hierarchical neural network involving two PCNNs. The image is presented to the network to generate binary barcodes (one per iteration) of the galaxies; the barcodes are unique to the input galactic image. In the current study, we exploit this property to identify optical galaxies by comparing the signatures (binary barcode) from a corresponding database. This revised version was published online in July 2006 with corrections to the Cover Date.     

Daily accumulation rates of marine debris on sub-Antarctic island beaches

The worlds’ oceans contain a large but unknown amount of plastic debris. We made daily collections of marine debris stranded at two sub-Antarctic islands to establish (a) physical causes of strandings, and (b) a sampling protocol to better estimate the oceans’ plastic loading. Accumulation rates at some beaches were dependent on tide and onshore winds. Most of the 6389 items collected were plastic (Macquarie 95%, Heard 94%) and discarded or lost fishing gear comprised 22% of those plastic items. Stalked barnacles (Lepas spp.) were a regular attachment on Macquarie debris but not at Heard Island. The daily accumulation rate of plastic debris on Macquarie Island was an order of magnitude higher than that estimated from monthly surveys during the same 4 months in the previous 5 years. This finding suggests that estimates of the oceans’ plastic loading are an order of magnitude too low.     

Vestan lithologies mapped by the visual and infrared spectrometer on Dawn

We present global lithological maps of the Vestan surface based on Dawn mission's Visible InfraRed (VIR) Spectrometer acquisitions with a spatial sampling of 200 m. The maps confirm the results obtained with the data set acquired by VIR with a spatial sampling of 700 m, that the reflectance spectra of Vesta's surface are dominated by pyroxene absorptions that can be interpreted within the context of the distribution of howardites, eucrites, and diogenites (HEDs). The maps also partially agree with the ground and Hubble Space Telescope observations: they confirm the background surface being an assemblage of howardite or polymict eucrite, as well as the location of a diogenitic‐rich spot; however, there is no evidence of extended olivine‐rich regions in the equatorial latitudes. Diogenite is revealed on the Rheasilvia basin floor, indicating that material of the lower crust/mantle was exposed. VIR also detected diogenites along the scarp of Matronalia Rupes, and the rims of Severina and a nearby, unnamed crater, and as ejecta of Antonia crater. The diogenite distribution is fully consistent with petrological constraints; although the mapped distribution does not provide unambiguous constraints, it favors the hypothesis of a magma ocean.     

Factors influencing the behavior of buried pipelines subjected to earthquake faulting

Seismic ground faulting is a severe hazard for continuous buried pipelines. Over the years, researchers have attempted to understand pipe behavior, most frequently via numerical modeling and simulation. However, there has been little, if any, physical modeling and tests to verify the numerical modeling approaches and assumptions. This paper presents results of five pairs of centrifuge tests designed to investigate the influence of various factors on the behavior of buried high-density polyethylene (HDPE) pipelines subjected to strike-slip faulting. Parameters considered are the soil moisture content, fault offset rate, relative burial depth (H/D), and pipe diameter. The centrifuge test results show that pipe behavior, specifically pipe strain, is nominally not affected by the soil moisture content and fault offset rate when the pipe is subjected to strike-slip faulting. On the other hand, the burial depth ratio (H/D) and pipe diameter influence peak pipe strain, and in some cases, the ground soil failure pattern.     

A multilevel path analysis of contact frequency between social network members

Recently, there has been an increasing interest in the role of social networks in spatial-choice and travel behavior. It has been acknowledged that social activities and the travel for these activities can emerge from individuals’ social networks and that social activities are responsible for an important portion of travel demand. The influence of information and communication technologies (ICT’s) is also important in this respect. The purpose of the paper is to examine the effects of characteristics of egos and ego-alter relationships on the frequency of social interaction by different communication modes, using multilevel path analysis. The analyses are based on social network data collected in 2008 in the Eindhoven region in the Netherlands among 116 respondents. The results indicate a complementary relationship between contact frequencies by different modes. The contact frequencies of the different modes, especially face-to-face and telephone, can also be largely explained by the ego’s personal characteristics and the type of relationship and the distance between ego and alter.     

Effective intellectual property protection of traditional knowledge of plants and their uses: an example from Australia

Intellectual property rights (IPR) to traditional knowledge (TK) about Australian native plants could justifiably be described as a birthright of Australian Aboriginal people. However, as is generally the case throughout the world, this right is currently not protected under Australian law. A case study is presented describing the approach that was taken to protecting the plant knowledge rights of traditional knowledge (TK) holders who participated in research at Titjikala, central Australia. From a review of international efforts aimed at developing a legal regime for protection of traditional knowledge (TK) intellectual property rights (IPR), we found that protecting traditional knowledge (TK) of plants and their uses is most likely to be achieved through the development of effective protocols for preserving and recording traditional knowledge (TK) and the use of contract law in commercial applications of that knowledge. The process of negotiating a research agreement between the research organisations and the community is described. Relationship building and a partnership approach based on trust and mutual respect were found to be of fundamental importance. The negotiated agreement ensures that the community has an equal share to research partners in any benefits that might arise from commercialisation of research findings. The approach to benefit sharing developed in this project has application in other research projects in which the sharing of traditional knowledge (TK) is a fundamental and essential component of the research process.     

GIS-based analysis of foundation repairs and soil conditions in the Dallas-Fort Worth region,Texas

The Dallas-Fort Worth region is subject to a severe expansive soils hazard, resulting in costly damage to many thousands of residential foundations each year. A GIS is used to examine relationships between a sample of approximately 10,000 foundation repair addresses and geologic and soil conditions. The study results show that foundation repairs are concentrated in areas underlain by bedrock, surficial deposits and soils that promote high shrink–swell potentials. A linear extensibility index, designed as an index of overall shrink–swell potential explains about 48% of the variation in the prevalence of repairs. Repairs are concentrated on soils that underlay many areas of new urban growth in the DFW region, suggesting that the incidence of foundation repairs in these areas will probably increase in the future. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.