Mapping diversified peri-urban agriculture – potential of object-based versus per-field land cover/land use classification

High spatial resolution satellite data contribute to improving land cover/land use (LCLU) classification in agriculture. A classification procedure based on Quickbird satellite image data was developed to map LCLU of diversified agriculture at sub-communal and communal level (7 km²). Segmentation performance of the panchromatic band in combination with high pass filters (HPF) was tested first. Accuracy of field boundary delineation was evaluated by an object-based segmentation, a per-field and a manual classification, along with a quantitative accuracy assessment. Sub-communal classification revealed an overall accuracy of 84% with a κ coefficient of 0.77 for the per-field vector segmentation compared to an overall accuracy of 56–60% and a κ coefficient of 0.37–0.42 for object-based approaches. Per-field vector segmentation was thus superior and used for LCLU classification at communal level. Overall accuracy scored 83% and the κ coefficient 0.7. In diversified agriculture, per-field vector segmentation and classification achieved higher classification results.     

Environmental Impact Assessment of High Pressure Water Scrubbing Biogas Upgrading Technology

The aim of this work was to assess the burdens of a process in terms of environmental and health impacts, resource depletion issues, and energy demand based on the ability of the Life Cycle Assessment methodology to link the environmental impacts with the mass and energy flows. The analysis was done in terms of process and environmental performances of high pressure water scrubbing (HPWS) system applied for biogas upgrading. The application of process simulation based on the Aspen Plus® software has been considered as supportive for the calculation of mass and energy balances. Data processed using GaBi 4: Software showed that global warming, acidification, and human toxicity potentials were the main impact categories associated with the HPWS process. These indicators are largely related to the exhaust gas from the desorption column and the indirect emissions generated during energy consumption. The life cycle inventory study resulted in the development of a database with a vast inventory of data regarding HPWS technology. A basis for assessing potential improvements in the environmental performance of the system is provided. Future studies in this area will address the economical evaluation of the HPWS technology, so as to maximize economic efficiency and minimize environmental impacts.     

Fluid-mediated modification of garnet interiors under ultrahigh-pressure conditions

We report the results of a novel experimental study on eclogitic garnets with abundant inclusions of clinozoisite, quartz and rutile subjected to temperatures (T) of 800–1100 °C and a pressure (P) of 4 GPa, representative of ultrahigh-pressure (UHP) metamorphic terranes such as the Kokchetav massif, Saxonian Erzgebirge, etc. The experiments reveal extremely rapid recrystallization and partial melting of garnet interiors controlled by fluids liberated from the breakdown of the hydrous mineral inclusions. The traditional assumption that inclusions of minerals and primary fluid inclusions should be representative of the peak or even earlier metamorphic history cannot be strictly applied in this case. We argue that inclusions in UHP garnets may mirror P–T conditions postdating growth of the host crystal or even P–T conditions never actually experienced by the rock itself. The above modification of garnet interiors produces a typical patchy microstructure that occurs in natural eclogitic garnet from the diamond-bearing UHP Kokchetav massif.     

XMM–Newton observations of the black hole X-ray transient XTE J1650–500 in quiescence

We report the result of an XMM–Newton observation of the black hole X-ray transient XTE J1650–500 in quiescence. The source was not detected, and we set upper limits on the 0.5–10 keV luminosity of  0.9–1.0 × 10³¹ erg s⁻¹  (for a newly derived distance of 2.6 kpc). These limits are in line with the quiescent luminosities of black hole X-ray binaries with similar orbital periods (∼7–8 h).     

Development of Synthetic Fiber-Reinforced Electro-Optical-Mechanical Cables for Use With Moored Buoy Observatories

We consider an alternative to traditional high-modulus synthetic electro-optical-mechanical (EOM) mooring cables that are being used in single-point moorings for deep-ocean observatories. The alternative cable design is based on using low-modulus nylon or polyester fibers as the strength member. High-modulus EOM cables such as those that use Vectran fibers as the strength member are usually constructed with the conductors and optical fibers in the core and the strength member on the outside. The key aspect of the new design is that the strength member is placed in the center of the cable and the conductors and fibers are wrapped around the outside at a high helix angle to accommodate stretching of the center-strength-member. A comparison of the static and dynamic responses of moorings constructed with nylon, polyester, and Vectran EOM cables (for mooring scopes of 1.1 and 1.2 and deployment depths of 1800, 3000, and 5000 m) shows that the maximum total tensions of moorings made with nylon EOM cables are lowest under all conditions. Differences between the nylon and the Vectran EOM cable moorings are due principally to the differences in the dynamic tensions. Differences between the nylon and the polyester EOM cable moorings are due mainly to differences in static tensions caused by the higher specific gravity of polyester fibers. Reduction in the scope of all the moorings from 1.2 to 1.1 resulted in significantly higher tensions for the polyester and Vectran EOM cable moorings but only slightly higher tensions for the nylon EOM cable moorings     

Characterization of lake water and ground water movement in the littoral zone of Williams Lake,a closed‐basin lake in north central Minnesota

Williams Lake, Minnesota is a closed‐basin lake that is a flow‐through system with respect to ground water. Ground‐water input represents half of the annual water input and most of the chemical input to the lake. Chemical budgets indicate that the lake is a sink for calcium, yet surficial sediments contain little calcium carbonate. Sediment pore‐water samplers (peepers) were used to characterize solute fluxes at the lake‐water–ground‐water interface in the littoral zone and resolve the apparent disparity between the chemical budget and sediment data. Pore‐water depth profiles of the stable isotopes δ¹⁸O and δ²H were non‐linear where ground water seeped into the lake, with a sharp transition from lake‐water values to ground‐water values in the top 10 cm of sediment. These data indicate that advective inflow to the lake is the primary mechanism for solute flux from ground water. Linear interstitial velocities determined from δ²H profiles (316 to 528 cm/yr) were consistent with velocities determined independently from water budget data and sediment porosity (366 cm/yr). Stable isotope profiles were generally linear where water flowed out of the lake into ground water. However, calcium profiles were not linear in the same area and varied in response to input of calcium carbonate from the littoral zone and subsequent dissolution. The comparison of pore‐water calcium profiles to pore‐water stable isotope profiles indicate calcium is not conservative. Based on the previous understanding that 40–50 % of the calcium in Williams Lake is retained, the pore‐water profiles indicate aquatic plants in the littoral zone are recycling the retained portion of calcium. The difference between the pore‐water depth profiles of calcium and δ¹⁸O and δ²H demonstrate the importance of using stable isotopes to evaluate flow direction and source through the lake‐water–ground‐water interface and evaluate mechanisms controlling the chemical balance of lakes. Published in 2003 by John Wiley & Sons, Ltd.     

X-ray emission from dwarf galaxies: IC 2574 revisited

Until recently, few unequivocal detections had been reported of the hot, X-ray emitting gas thought to be associated with the large, coherent structures variously described as supershells or superbubbles in dwarf irregular (dIrr) galaxies. In this contribution we report follow-up XMM-Newton and Chandra observations of our ROSAT detection of X-ray emission associated with the supergiant shell in the nearby dIrr galaxy IC 2574, a member of the M 81 group of galaxies. The spectral properties of the X-ray source suggest that we are dealing with a young (age < 2000 yr) supernova remnant (SNR). This SNR is most likely one of the many supernovae which have exploded in that region and which have created the impressive supergiant HI shell. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Ogle-Tr-56 Star–Planet System

We simultaneously fitted light and velocity data for the star–planet system OGLE-TR-56 with the Wilson–Devinney (WD) binary star program. We solved for orbital and planet parameters, along with the ephemeris using all currently available observational data. Parameters for the star (OGLE-TR-56a) were kept fixed at values derived from spectral characteristics and stellar evolutionary tracks. Our results are in good agreement with parameters obtained by other authors and have slightly smaller errors. We found no significant change in orbital period that may be due to orbital decay.