Energy and long-range disorder in simple spinels

Interionic potential calculations conducted on simple spinels in the framework of the Born model indicate that, within experimental uncertainties, observed control of P, T intensive variables on long-range disorder may be completely due to static effects. Parameterization of repulsive potentials allows us to rationalize the existing experimental data and quantify the variation of static energy, configuration entropy and static Gibbs free energy with temperature. The static energy of the investigated phases cannot be expressed in simple quadratic terms of the inversion parameter, as commonly assumed, but requires higher order terms. Knowledge of the longrange disorder at various temperatures allows us to express configurational entropy as a Maier-Kelley type polynomial expansion on temperature. As configurational entropy simply depends on the static part of the internal energy, the integration of the obtained functions in d T allows rapid evaluation of the effect of long-range disorder on the static part of energy.     

Determinants of species susceptibility to oxidative stress: A comparison of channel catfish and brown bullhead

Xenobiotic-mediated productions of reactive oxygen species, via enzymemediated redox cycling, have been implicated in a variety of toxicological phenomena including lipid peroxidation, enzyme inactivation and oxidative DNA damage leading to cancer. A comparison was undertaken of two benthic freshwater fish species that appear to differ markedly in their susceptibility to chemical carcinogenesis—the channel catfish (Ictalurus punctatus) and the more cancer-prone brown bullhead (Ameriurus nebulosus)-in terms of basic biochemical characteristics related to oxidative stress. This has included analysis of microsomal redox cycling of model xenobiotics (e.g. menadione) as well as antioxidant and other detoxifying enzymes in hepatic tissue of the two species. In addition, endpoints of oxidative stress, such as altered glutathione status and oxidative DNA damage, were examined. These studies have revealed numerous qualitative and quantitative differences between the two species both in terms of basal enzyme activities and in species response to model prooxidants. For example, bullhead appear to possess a greater capacity for microsomal redox cycling of xenobiotics, but have glutathione-dependent defense systems less able to withstand oxidative challenge. These and other interspecific differences have allowed for an improved understanding of the basic mechanisms which may underly species susceptibility to oxidative stress and critical manifestations such as cancer.     

Hydrogeology of the Nurra Region, Sardinia (Italy): basement-cover influences on groundwater occurrence and hydrogeochemistry

The Nurra district in the Island of Sardinia (Italy) has a Palaeozoic basement and covers, consisting of Mesozoic carbonates, Cenozoic pyroclastic rocks and Quaternary, mainly clastic, sediments. The faulting and folding affecting the covers predominantly control the geomorphology. The morphology of the southern part is controlled by the Tertiary volcanic activity that generated a stack of pyroclastic flows. Geological structures and lithology exert the main control on recharge and groundwater circulation, as well as its availability and quality. The watershed divides do not fit the groundwater divide; the latter is conditioned by open folds and by faults. The Mesozoic folded carbonate sequences contain appreciable amounts of groundwater, particularly where structural lows are generated by synclines and normal faults. The regional groundwater flow has been defined. The investigated groundwater shows relatively high TDS and chloride concentrations which, along with other hydrogeochemical evidence, rules out sea-water intrusion as the cause of high salinity. The high chloride and sulphate concentrations can be related to deep hydrothermal circuits and to Triassic evaporites, respectively. The source water chemistry has been modified by various geochemical processes due to the groundwater–rock interaction, including ion exchange with hydrothermal minerals and clays, incongruent solution of dolomite, and sulphate reduction.     

The expansion,limit and decline of the global marine fish catch

Catch of marine fish grew from after WW II–1989, at which point it stabilized. In 1996 it began to decline. It continues to decline now, at a time when earth's population is expected to reach 10 billion by 2050. Since the factors driving the increase are primarily the growth in income, population, technology of catching fish and ever increasing fishing effort, it is to be expected that the aggregate marine catch will continue to decline. This decline has important implications for marine ecosystems but primarily its importance relates to the human use of other global resources such as food, water and world's climate.     

Frequency‐dependent multi‐offset phase analysis of surface waves: an example of high‐resolution characterization of a riparian aquifer

Multi‐offset phase analysis of seismic surface waves is an established technique for the extraction of dispersion curves with high spatial resolution and, consequently, for the investigation of the subsurface in terms of shear wave velocity distribution. However, field applications are rarely documented in the published literature. In this paper, we discuss an implementation of the multi‐offset phase analysis consisting of the estimation of the Rayleigh wave velocity by means of a moving window with a frequency‐dependent length. This allows maximizing the lateral resolution at high frequencies while warranting stability at the lower frequencies. In this way, we can retrieve the shallow lateral variability with high accuracy and, at the same time, obtain a robust surface‐wave velocity measurement at depth. In this paper, we apply this methodology to a dataset collected for hydrogeophysical purposes and compare the inversion results with those obtained by using refraction seismics and electrical resistivity tomography. The surface‐wave results are in good agreement with those provided by the other methods and demonstrate a superior capability in retrieving both lateral and vertical velocity variations, including inversions. Our results are further corroborated by the lithological information from a borehole drilled on the acquisition line. The availability of multi‐offset phase analysis data also allows disentangling a fairly complex interpretation of the other geophysical results.     

Italian accelerometric archive: geological, geophysical and geotechnical investigations at strong-motion stations

Geological, geophysical and geotechnical investigations, for the characterization of the strong-motion recording sites managed by the Italian Civil Protection, have been carried out in the framework of the project “Italian strong-motion database in the period 1972–2004”. The project aimed at creating an updated database of strong-motion data acquired in Italy by different institutions in the time span 1972–2004, and at improving the quality of disseminated data. This article illustrates the state of the recording site characterization before the beginning of the project, explains the criteria adopted to select the sites where geophysical/geotechnical investigation have been performed and describes the results of the promoted field surveys.     

Local variability of the ground shaking during the 2009 L��Aquila earthquake (April 6, 2009��Mw 6.3): the case study of Onna and Monticchio villages

The 2009 Mw 6.3 L’Aquila event caused extensive damage in the city of L’Aquila and in some small towns in its vicinity. The most severe damage was recognized SE of L’Aquila town along the Aterno river valley. Although building vulnerability and near-source effects are strongly responsible for the high level of destruction, site effects have been invoked to explain the damage heterogeneities and the similarities between the 2009 macroseismic field with the intensities of historical earthquakes. The small village of Onna is settled on quaternary alluvium and suffered during the L’Aquila event an extremely heavy damage in the masonry structures with intensity IX–X on the Mercalli-Cancani-Sieberg (MCS) scale. The village of Monticchio, far less than 1.3 km from Onna, is mostly situated on Mesozoic limestone and suffered a smaller level of damaging (VI MCS). In the present paper, we analyze the aftershock recordings at seismic stations deployed in a small area of the middle-Aterno valley including Onna and Monticchio. The aim is to investigate local amplification effects caused by the near-surface geology. Because the seismological stations are close together, vulnerability and near-source effects are assumed to be constant. The waveform analysis shows that the ground motion at Onna is systematically characterized by large high-frequency content. The frequency resonance is varying from 2 to 3 Hz and it is related to alluvial sediments with a thickness of about 40 m that overlay a stiffer Pleistocene substrate. The ground motion recordings of Onna are well reproduced by the predictive equation for the Italian territory.     

The fluid phase in eclogites,glaucophane-bearing rocks and amphibolites from the central tauern window as deduced from fluid inclusion studies

Summary Fluid inclusions in rock forming quartz and in quartz from veins and Alpine fissures from eclogites and glaucophane bearing rocks of the southern Grossvenediger area as well as from amphibolitized eclogites and calcareous mica schists from the Grossglockner area (Austria) have been studied by microthermometry. The oldest fluid inclusions in the eclogites contain only CO₂ and are characterized by a very high density up to 1.15 g/cm³. From eclogite forming temperatures in the range of 500 to 550°C a trapping pressure of about 8 kb results for these inclusions. This pressure is in good agreement with that derived from the eclogite-forming mineral reactions. The amphibolites formed by retrogressive metamorphism from the eclogites show fluid inclusions containing H₂O and CO₂, the densities of the CO₂ being much lower compared to those of the fluid inclusions from the unaltered eclogites.

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Die fluide Phase in den Eklogiten, den glaukophanführenden Gesteinen und den Amphiboliten des zentralen Tauernfensters abgeleitet aus der Untersuchung der Flüssigkeitseinschlüsse

Zusammenfassung Es wurden die Flüssigkeitseinschlüsse von Gesteins- und Kluftquarzen aus den Eklogiten und glaukophanführenden Gesteinen des südlichen Großvenedigergebietes und aus Granatamphiboliten und Kalkglimmerschiefern aus dem Bereich des Großglockners (Österreich) mikrothermometrisch untersucht.Die ältesten Flüssigkeitseinschlüsse der Eklogite bestehen nur aus CO₂ mit einer sehr hohen Dichte bis 1.15 g/cm³. Aus dieser Dichte und den Temperaturen der eklogitbildenden Mineralreaktionen kann für diese nur CO₂ enthaltenden Einschlüsse ein Einschließungsdruck von etwa 8 kb errechnet werden, der mit den aus den Mineralreaktionen in den Eklogiten abgeleiteten Druckwerten übereinstimmt.Die aus Eklogiten durch Diaphtorese hervorgegangenen Amphibolite aus dem Gebiet des Großglockners enthalten keine CO₂-Einschlüsse hoher Dichte mehr. Es treten dort ausschließlich CO₂- und H₂O-führende Einschlüsse auf. Das CO₂ dieser Einschlüsse hat eine deutlich niedrigere Dichte als das CO₂ der Einschlüsse in den Eklogiten.

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With 2 Figures     

Assessing physical vulnerability in large cities exposed to flash floods and debris flows: the case of Arequipa (Peru)

Understanding the physical vulnerability of buildings and infrastructure to natural hazards is an essential step in risk assessment for large cities. We have interpreted high spatial resolution images, conducted field surveys, and utilized numerical simulations, in order to assess vulnerability across Arequipa, south Peru, close to the active El Misti volcano. The emphasis of this study was on flash floods and volcanic or non-volcanic hyperconcentrated flows, which recur on average every 3.5 years across the city. We utilized a geographic information system to embed vulnerability and hazard maps as a step to calculate risk for buildings and bridges along the Río Chili valley and two tributaries. A survey of ~1,000 buildings from 46 city blocks, different in age, construction materials, and land usage, provided architectural and structural characteristics. A similar survey of twenty bridges across the three valleys was based on structural, hydraulic, and strategic parameters. Interpretation of high spatial resolution (HSR) satellite images, which allows for quick identification of approximately 69 % of the structural building types, effectively supplemented field data collection. Mapping vulnerability has led us to pinpoint strategic areas in case of future destructive floods or flows. Calculated vulnerability is high if we examine structural criteria alone. We further consider physical setting with the most vulnerable city blocks located on the lowermost terraces, perpendicular or oblique to the flow path. Statistical analysis conducted on 3,015 city blocks, considering nine criteria identified from HSR images, indicated that building-type heterogeneity and the shape of the city blocks, along with building and street network density, are the most discriminant parameters for assessing vulnerability.     

Ein Vergleich der Ergebnisse von A. Bianchi und F. Karl über die granitischen Gesteine des Zillertales und des Großvenedigers (Hohe Tauern)

Zusammenfassung Es wurde in einem Vergleichsreferat zwischen den Untersuchungsergebnissen vonA. Bianchi (1934) undF. Karl (1959) an den granitischen Gesteinen des Zillertal- und Großvenedigerbereiches (Hohe Tauern) und dem Tonalitmassiv des Rieserferner gezeigt, daß sich die Beobachtungen und Teilergebnisse vonBianchi trotz unterschiedlicher genetischer Auswertung gut in das Gesamtbild vonKarl einordnen lassen. Wichtig ist dafür, daß die Mehraktigkeit der alpidischen Orogenese für die Beurteilung des Verhältnisses zwischen Kristallisation und Deformation berücksichtigt wird und daß aus der zusammengefaßten Gesteinsgruppe der granodioritischen, schichtigen oder massigen Orthogneise mit normaler Biotit-reicher Facies tonalitisierte Paragneise (nachKarl Tonalitische Gneise) abgetrennt werden. Für die petrochemischen Vergleiche wurden alle interessierenden AnalysenBianchis auf Kationoxydprozente (Eskola) verrechnet und in vergleichbaren Verhältniszahlen gegenübergestellt.Mit 4 Textabbildungen