Ein tektonischer Schnitt durch Mittelperu

Zusammenfassung Es wird ein kombinierter Profilschnitt durch Mittelperu zwischen der Küste bei Lima und dem brasilianischen Schild vorgelegt, wobei die wesentlichen, am telefonischen Aufbau Mittelperus beteiligten Felder in Kürze charakterisiert werden. Das Vergenzverhalten im Faltenbau und die jeweilige Ausbildung der Feldergrenzen werden besonders betont.

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A combined section of Central Peru from the coast near Lima to the Brazilian shield is given with a brief outline of the main structural units, which form part of the tectonic framework of Central Peru. Special emphasis is laid on the overturn of the folding and the characteristics of the zones separating the units from each other.

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Résumé On vous donne un profil combiné du Pérou Central de son littoral près de Lima jusqu'à la masse cristalline du Brésil avec une brève caractérisation des unités structurales principales qui font partie de la charpente tectonique du Pérou Central. En particulier, on fait ressortir le déversement du plissement et les qualités des zones qui séparent les différentes unités.

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Habitat requirements for submerged aquatic vegetation in Chesapeake Bay: Water quality, light regime, and physical-chemical factors

We developed an algorithm for calculating habitat suitability for seagrasses and related submerged aquatic vegetation (SAV) at coastal sites where monitoring data are available for five water quality variables that govern light availability at the leaf surface. We developed independent estimates of the minimum light required for SAV survival both as a percentage of surface light passing though the water column to the depth of SAV growth (PLW _min) and as a percentage of light reaching reaching leaves through the epiphyte layer (PLL _min). Value were computed by applying, as inputs to this algorithm, statistically dervived values for water quality variables that correspond to thresholds for SAV presence in Chesapeake Bay. These estimates ofPLW _min andPLL _min compared well with the values established from a literature review. Calcultations account for tidal range, and total light attenuation is partitioned into water column and epiphyte contributions. Water column attenuation is further partitioned into effects of chlorophylla (chla), total suspended solids (TSS) and other substances. We used this algorithm to predict potential SAV presence throughout the Bay where calculated light available at plant leaves exceededPLL _min. Predictions closely matched results of aerial photographic monitoring surveys of SAV distribution. Correspondence between predictions and observations was particularly strong in the mesohaline and polythaline regions, which contain 75–80% of all potential SAV sites in this estuary. The method also allows for independent assessment of effects of physical and chemical factors other than light in limiting SAV growth and survival. Although this algorithm was developed with data from Chesapeake Bay, its general structure allows it to be calibrated and used as a quantitative tool for applying water quality data to define suitability of specific sites as habitats for SAV survival in diverse coastal environments worldwide.     

Robust Kalman filter for rank deficient observation models

A robust Kalman filter is derived for rank deficient observation models. The datum for the Kalman filter is introduced at the zero epoch by the choice of a generalized inverse. The robust filter is obtained by Bayesian statistics and by applying a robust M-estimate. Outliers are not only looked for in the observations but also in the updated parameters. The ability of the robust Kalman filter to detect outliers is demonstrated by an example. Received: 8 November 1996 / Accepted: 11 February 1998     

Meteorological Aspects, Ozone, and Solar Radiation Measurements During POPCORN 1994

Meteorological data, ozone mixing ratios, and photolysis frequencies for the period August 2 to August 24, 1994, are presented and discussed in support of the field campaign POPCORN (Photochemistry of Plant Emitted Compounds and OH Radicals in Northeastern Germany). Measurements of temperature, ozone, and wind speed at different heights are used to evaluate micro-meteorological parameters. The observations provide information about local influences on the air mass composition. The analysis of radio sonde data of nearby stations provides the height of the planetary boundary layer.     

Oxygen isotope partitioning between phosphate and carbonate in mammalian apatite

The oxygen isotope compositions of phosphate and structural carbonate in mammalian enamel and bone apatite are linked to that of body water at constant body temperature near 37°C, but the isotope systematics of oxygen in structural carbonate are not well understood. Using coupled measurements of the oxygen isotope composition of structural carbonate and phosphate from horse tooth enamel, the apparent oxygen isotope fractionation factor between structural carbonate and body water is estimated to be 1.0263 ± 0.0014. These estimates provide a quantitative basis for using the oxygen isotope composition of structural carbonate in mammalian biogenic apatite for ecological, climatological, and physiological reconstruction.     

Magnetic properties of feroxyhyte (δ-FeOOH)

Magnetization curves and high-field Mössbauer spectra are used to deduce a model for the magnetic order in synthetic samples of δ-FeOOH (feroxyhyte), which takes account of the changes in magnetization when the samples are heated at 105 °C. Feroxyhyte is essentially a planar antiferromagnet with the net sublattice moments aligned parallel or antiparallel to c. Each particle acquires a net moment due to the very small number of layers along the c-direction, and the presence of surface steps causing the formation of ferrimagnetic domains with an odd number of layers. There is some spin canting which is related to the crystallinity of the sample. The decrease in magnetization following heating is mainly due to an increase in the extent of antiferromagnetic coupling between the closely packed ferrimagnetic particles, but changes in the spin canting within the bulk may also contribute. A typical, rather well crystallized specimen has magnetization σ=14 JT^?1 kg^?1 and Curie temperature T _c=455 K.