Jet drop enrichment of bacteria,virus, and dissolved organic material

Four parameters that control the enrichment of bacteria in jet drops are bubble scavenging, drop size, drop position in the jet set, and the type of bacteria. Without the scavenging of bacteria as a bubble rises through the water it is doubtful that the observed enrichment factors, EF, greater than 1000 could be obtained. There is a maximum in EF as a function of top jet drop size, and the EF decreases from the top to the bottom drop of the jet set. The efficiency by which bubbles scavenge bacteria varies with species. Presumably these parameters apply in some degree to the EF of virus in jet drops. Dissolved organic material in natural waters can adsorb to bubbles and contribute to a large EF in jet drops, but there is a feedback mechanism whereby changes in bubble surface free energy modify the jet drop-size distribution. However, there is reason to believe this will not significantly influence the jet drop-size distribution produced by bubbles in the sea.     

The dynamics of offshore gravity platforms: Some insights afforded by a two degree of freedom model

This paper presents some findings of an investigation into the dynamic behaviour of offshore gravity platforms excited by waves. Results obtained from a finite element model are presented in the form of dynamic magnification factor curves for two structures typical of current concrete platform designs. In order to facilitate interpretation of these results a simple two degree of freedom model is developed and the equivalent results presented. These are found to be very similar to those obtained from the more detailed idealization, and it is therefore concluded that the principal mechanisms involved in the dynamic behaviour of offshore gravity structures are adequately represented in the simple model. Several useful insights into this behaviour are then achieved by closer examination of the two degree of freedom configuration.     

Chemical balance of the Earth's crust

The chemical composition and lithologic proportions of average sedimentary and igneous rocks are analyzed by a linear least squares regression. The best set of internally consistent data for sediments in geosynclines, continental platforms, deep ocean basin and the average igneous and sedimentary rock are shown below. These results are based on published estimates of the chemical composition of igneous and sedimentary rocks and the relative volume of sediments on the continents and in the deep ocean basins.

$\text{SiO}{}_2\text{A1}{}_2\text{O}{}_3\text{Fe(total)}\text{MgO}\text{CaO}\text{Na}{}_2\text{O}\text{K}{}_2\text{O}\text{CO}{}_2\text{Geosynclines}\text{55.2}\text{12.0}\text{3.6}\text{3.2}\text{8.3}\text{1.0}\text{2.4}\text{8.6}\text{Platforms}\text{49.5}\text{10.7}\text{3.2}\text{3.3}\text{12.3}\text{0.9}\text{2.2}\text{10.8}\text{Av. sed.}\text{55.9}\text{13.8}\text{4.4}\text{3.6}\text{5.8}\text{1.2}\text{2.6}\text{5.2}\text{Av. ig.}\text{59.0}\text{15.0}\text{5.0}\text{3.6}\text{7.0}\text{3.4}\text{3.2}$

The lithologic proportions are: geosyncline—24% sandstone, 58% shale, and 16% carbonate; platform—23% sandstone, 49% shale and 26% carbonate; average sedimentary rock—13% sandstone, 33% shale, 12% carbonate, and 41% pelagic; average igneous rock is approximately 2/3 granodiorite and 1/3 tholeiite. These data indicate a chemical balance of major elements in the Earth's upper crust during the last 1.5 b.y.     

Hard Burst Emission from the Soft Gamma Repeater SGR 1900+14

We present evidence for burst emission from SGR 1900+14 with a power-law high-energy spectrum extending beyond 500 keV. Unlike previous detections of high-energy photons during bursts from soft gamma repeaters (SGRs), these emissions are not associated with extraordinarily bright flares. Not only is the emission hard, but the spectra are better fitted by D. Band's gamma-ray burst (GRB) function rather than by the traditional optically thin thermal bremsstrahlung model. We find that the spectral evolution within these hard events obeys a hardness/intensity anticorrelation. Temporally, these events are distinct from typical SGR burst emissions in that they are longer ( approximately 1 s) and have relatively smooth profiles. Despite a difference in peak luminosity of greater, similar1011 between these bursts from SGR 1900+14 and cosmological GRBs, there are striking temporal and spectral similarities between the two kinds of bursts, aside from spectral evolution. We outline an interpretation of these events in the context of the magnetar model.     

Geology of Santa Fe island: The oldest galapagos volcano

Santa Fe Island was a volcanic center when it emerged 3.9 ± 0.6 m.y. ago. Later upfaulting of a horst along the central axis of the island dominates its present morphology. Santa Fe is made up of evolved transitional lavas that are not related by fractional crystallization alone. Source heterogeneties, differing degrees of melting, or open-system magma chambers may explain the observed trace element variations.Santa Fe, Baltra, and Española make up a geologic subprovince in the central Galapagos: they are older than the other islands, and their lavas are compositionally similar. At the time of their emergence, the three islands were in a tectonic setting similar to that of the young western and central Galapagos Island.     

The life and times of Big Bertha: lunar breccia 14321

The lithic units of polymict breccia 14321 (Big Bertha) have been grouped according to composition, texture, degree of metamorphism, and additional criteria based on a systematic study of the interrelationships of all clast-matrix pairs. From this information it has been possible to reconstruct the assembly and metamorphic history of this breccia. The earliest formed fragmental component of 14321 (microbreccia-1) is dominated by KREEP-rich norite, extruded and subsequently brecciated and lithified in an ejecta blanket at approximately 1000°C in the general region of Mare Imbrium after the Serenitatis impact but prior to the Imbrium impact. This early microbreccia component and lesser amounts of mare-type basalt, microgranite, rhyolite glass, anorthosite and olivine microbreccia were assembled at the Apollo 14 site as part of the Fra Mauro ejecta blanket from the Imbrium impact. The resulting microbreccia-3 incorporates all the lithic types above and accretionary lapilli structures (microbreccia-2) in a dark matrix annealed at approximately 700°C. A later impact on the Fra Mauro excavated and mutually abraded microbreccia-3 and a local, 14321-type, basalt which were assembled into polymict breccia 14321. Final placement of 14321 at its sampling location was accomplished during the minor Cone Crater impact event.     

Toppling rock slope failures examples of analysis and stabilization

SummaryToppling Rock Slope Failures — Examples of Analysis and Stabilization Three case histories of toppling failures of rock slopes, and the methods used to ensure that failure did not disrupt operations below the slope, are described. The application of Goodman and Bray's limit equilibrium analysis of multi-block failures to these three slopes is demonstrated.The first failure occurred in a 20 m high granite slope that was stabilized by removing the top 6 m and installing a number of tensioned rock anchors in the toe. The second failure occurred in a sequence of folded sandstone, shale and coal. This slide was too large to stabilize, so the movement rate was monitored while mining continued in the pit below until shortly before failure took place. In the third failure, the top 8 m of a single 12 m high toppling block was removed by blasting to prevent further rotational movement.

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ZusammenfassungKippvorgänge beim Bruch von Felsböschungen — Beispiele für die Berechnung und Stabilisierung Es werden drei Fallstudien von Brüchen von Felsböschungen durch Kippen und die dabei angewendeten Sicherungsmethoden beschrieben. Die Anwendung der Grenzgleichgewichtsbetrachtung von Massenbewegungen, die durch Kippvorgänge ausgelöst wurden, nach Goodman and Bray, auf drei Felshänge wird gezeigt.Der erste Bruch ereignete sich in einer 20 m hohen Böschung in Granit. Die Stabilisierung bestand in der Entfernung der obersten 6 m und der Einbringung von einigen Vorspannankern. Der zweite Bruch ereignete sich in einer Serie von gefalteten Sandsteinen, Schiefern und Kohlen. Da die Größe dieser Rutschung eine Stabilisierung unmöglich machte, wurden die Bewegungen genau registriert und der Abbau bis kurz vor dem eigentlichen Bruch fortgesetzt. Das dritte Beispiel ist ein einzelner 12 m hoher, kippender Block, dessen oberste 8 m weggesprengt wurde, um ein weiteres Kippen zu verhindern.

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RésuméDéfauts par chute de rampes rocheuses — Exemples des analyses et de stabilisation Ce résumé décrit trois événements de rupture de pentes rocheuses et les méthodes de stabilisation utilisées. Dans ces trois cas l'auteur montre l'utilisation de l'analyse de la limite d'équilibre des masses rocheuses pour un mouvement de basculement selon Goodman et Bray.Le premier cas a eu lieu sur une rampe granitique de 20 m hauteur, laquelle a été stabilisée en 6 m de roche au sommet et en possant quelque d'ancrage au pied de la pente. La deuxième défaut s'a produit avec une séquence de roches de formation gréseuse, d'argile schisteuse et du charbon. Cette glissement a été trop grande pour être stabilisée, donc la raison de mouvement a été controlée au même temps qu'on travaillait dans le puit au dessous quelque temps avant que le défaut se produisse. Dans le troisième défaut les 8 m de sommet d'un seul bloc rocheux ont été dépilés par des méthodes explosifs pour prévenir ultérieur mouvements rotatives.

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With 6 Figures     

The 1919–1920 eruption of Mauna Iki,Kilauea: chronology,geologic mapping,and magma transport mechanisms

Utilizing historical accounts, field mapping, and photogeology, this paper presents a chronology of, and an analysis of magma transport during, the December 1919 to August 1920 satellitic shield eruption of Mauna Iki on the SW rift zone of Kilauea Volcano, Hawaii. The eruption can be divided into four stages based on the nature of the eruptive activity. Stage 1 consisted of the shallow injection of a dike from the summit region to the eventual eruption site 10 km downrift. During stage 2, a low ridge of pahoehoe formed in the vent area; later a large a'a flow broke out of this ridge and flowed 8.5 km SW at an average flow front velocity of 0.5 km/day. The eruption continued until mid-August producing almost exclusively pahoehoe, first as gas-rich overflows from a lava pond (stage 3), and later as denser tube-fed lava (stage 4) that reached almost 8 km from the vent at an average flow-front velocity of 0.1 km/day. Magma transport during the Mauna Iki eruption is examined using three criteria: (1) eruption characteristics and volumetric flow rates; (2) changes in the surface height of the Halemaumau lava lake; and (3) tilt measurements made at the summit of Kilauea. We find good correlation between Halemaumau lake activity and the eruptive stages. Additionally, the E-W component of summit tilt tended to mimic the lake activity. The N-S component, however, did not. Multiple storage zones in the shallow summit region probably accounted for the decoupling of E-W and N-S tilt components. Analysis of these criteria shows that at different times during the eruption, magma was either emplaced into the volcano without eruption, hydraulically drained from Halemaumau to Mauna Iki, or fed at steady-state conditions from summit storage to Mauna Iki. Volume calculations indicate that the supply rate to Kilauea during the eruption was around 3 m³/s, similar to that calculated during the Mauna Ulu and Kupaianaha shield-building eruptions, and consistent with previously determined values of long-term supply to Kilauea.     

Spatially resolved kinematics and stellar populations of brightest cluster and group galaxies

We present an examination of the kinematics and stellar populations of a sample of three brightest group galaxies (BGGs) and three brightest cluster galaxies (BCGs) in X-ray groups and clusters. We have obtained high signal-to-noise ratio Gemini/Gemini South Multi-Object Spectrograph (GMOS) long-slit spectra of these galaxies and use Lick indices to determine ages, metallicities and α-element abundance ratios out to at least their effective radii. We find that the BGGs and BCGs have very uniform masses, central ages and central metallicities. Examining the radial dependence of their stellar populations, we find no significant velocity dispersion, age, or α-enhancement gradients. However, we find a wide range of metallicity gradients, suggesting a variety of formation mechanisms. The range of metallicity gradients observed is surprising, given the homogeneous environment these galaxies probe and their uniform central stellar populations. However, our results are inconsistent with any single model of galaxy formation and emphasize the need for more theoretical understanding of both the origins of metallicity gradients and galaxy formation itself. We postulate two possible physical causes for the different formation mechanisms.     

Application of the SPARROW model in watersheds with limited information: a Bayesian assessment of the model uncertainty and the value of additional monitoring

How can spatially explicit nonlinear regression modelling be used for obtaining nonpoint source loading estimates in watersheds with limited information? What is the value of additional monitoring and where should future data‐collection efforts focus on? In this study, we address two frequently asked questions in watershed modelling by implementing Bayesian inference techniques to parameterize SPAtially Referenced Regressions On Watershed attributes (SPARROW), a model that empirically estimates the relation between in‐stream measurements of nutrient fluxes and the sources/sinks of nutrients within the watershed. Our case study is the Hamilton Harbour watershed, a mixed agricultural and urban residential area located at the western end of Lake Ontario, Canada. The proposed Bayesian approach explicitly accounts for the uncertainty associated with the existing knowledge from the system and the different types of spatial correlation typically underlying the parameter estimation of watershed models. Informative prior parameter distributions were formulated to overcome the problem of inadequate data quantity and quality, whereas the potential bias introduced from the pertinent assumptions is subsequently examined by quantifying the relative change of the posterior parameter patterns. Our modelling exercise offers the first estimates of export coefficients and delivery rates from the different subcatchments and thus generates testable hypotheses regarding the nutrient export ‘hot spots’ in the studied watershed. Despite substantial uncertainties characterizing our calibration dataset, ranging from 17% to nearly 400%, we arrived at an uncertainty level for the whole‐basin nutrient export estimates of only 36%. Finally, we conduct modelling experiments that evaluate the potential improvement of the model parameter estimates and the decrease of the predictive uncertainty if the uncertainty associated with the current nutrient loading estimates is reduced. Copyright © 2012 John Wiley & Sons, Ltd.