A tubular protozoan predator: a burrow selectively filled with tubular agglutinated protozoans (Xenophyophorea, Foraminifera) in the abyssal South China Sea

We report the occurrence of an unusual agglutinated protozoan-filled burrow recovered in a box core collected in 1998 from a depth of 2496 m in the South China Sea. The onion-shaped burrow occurring some 8 cm beneath the sediment surface was packed full with specimens of xenophyophoreans and foraminifera dominated by a single genus (Aschemonella) that had been living on the surface of the 1991 Mt. Pinatubo ash layer. This selective scavenging of epibenthic tubular agglutinated protozoans contributes to the patchiness of the benthic fauna on the sea floor. Because the tubular protozoans selectively agglutinate mafic mineral grains from the volcanic ash, two levels of biological scavenging are involved with the redistribution of these volcanic grains

Sediment disturbance caused by a suspension-feeding tubular agglutinated foraminifer

We report the occurrence of in-situ sediment disturbance caused by a specimen of Rhabdammina observed in life position on the 1991 Mt. Pinatubo ash layer in the abyssal South China Sea. The specimen extracts sediment grains from the ash layer to build its agglutinated test, causing a depression, or “moat” to form around the base of the specimen. We suspect that such fine-scale disturbance caused by large, erect tubular foraminifera is a common feature of the fossil record in deep-sea settings

Lower Bound for Convex Hull Area and Universal Cover Problems

In this paper, we provide a lower bound for an area of the convex hull of points and a rectangle in a plane. We then apply this estimate to establish a lower bound for a universal cover problem. We showed that a convex universal cover for a unit length curve has area at least 0.232239. In addition, we show that a convex universal cover for a unit closed curve has area at least 0.0879873.Comment: 12 pages, 9 figure

Seed particle formation for silicate dust condensation by SiO nucleation

Clustering of the abundant SiO molecules has been discussed as a possible mechanism of seed particle formation for silicate dust in stellar outflows with an oxygen rich element mixture. Previous results indicated that condensation temperatures based on this mechanism are significant lower than what is really observed. This negative result strongly rests on experimental data on vapour pressure of SiO. New determinations show the older data to be seriously in error. Here we aim to check with improved data the possibility that SiO nucleation triggers the cosmic silicate dust formation. First we present results of our measurements of vapour pressure of solid SiO. Second, we use the improved vapour pressure data to re-calibrate existing experimental data on SiO nucleation from the literature. Third, we use the re-calibrated data on SiO nucleation in a simple model for dust-driven winds to determine the condensation temperature of silicate in stellar outflows from AGB stars. We show that onset of nucleation under circumstellar conditions commences at higher temperature than was previously found. Calculated condensation temperatures are still by about 100 K lower than observed ones, but this may be due to the greenhouse effect of silicate dust temperatures. The assumption that the onset of silicate dust formation in late-type M stars is triggered by cluster formation of SiO is compatible with dust condensation temperatures derived from IR observations.Comment: 11 pages, 11 figure

Toward reliable morphology assessment of thermosets via physical etching: Vinyl ester resin as an example

The morphology of peroxide-cured, styrene crosslinked, bisphenol A-based vinyl ester (VE) resin was investigated by atomic force microscopy (AFM) after ‘physical’ etching with different methods. Etching was achieved by laser ablation, atmospheric plasma treatment and argon ion bombardment. Parameters of the etching were varied to get AFM scans of high topography resolution. VE exhibited a nanoscaled nodular structure the formation of which was ascribed to complex intra- and intermolecular reactions during crosslinking. The microstructure resolved after all the above physical etching techniques was similar provided that optimized etching and suitable AFM scanning conditions were selected. Nevertheless, with respect to the ‘morphology visualization’ these methods follow the power ranking: argon bombardment > plasma treatment > laser ablation

Rain estimation from satellites: An examination of the Griffith-Woodley technique

The Griffith-Woodley Technique (GWT) is an approach to estimating precipitation using infrared observations of clouds from geosynchronous satellites. It is examined in three ways: an analysis of the terms in the GWT equations; a case study of infrared imagery portraying convective development over Florida; and the comparison of a simplified equation set and resultant rain map to results using the GWT. The objective is to determine the dominant factors in the calculation of GWT rain estimates. Analysis of a single day's convection over Florida produced a number of significant insights into various terms in the GWT rainfall equations. Due to the definition of clouds by a threshold isotherm the majority of clouds on this day did not go through an idealized life cycle before losing their identity through merger, splitting, etc. As a result, 85% of the clouds had a defined life of 0.5 or 1 h. For these clouds the terms in the GWT which are dependent on cloud life history become essentially constant. The empirically derived ratio of radar echo area to cloud area is given a singular value (0.02) for 43% of the sample, while the rainrate term is 20.7 mmh-1 for 61% of the sample. For 55% of the sampled clouds the temperature weighting term is identically 1.0. Cloud area itself is highly correlated (r=0.88) with GWT computed rain volume. An important, discriminating parameter in the GWT is the temperature defining the coldest 10% cloud area. The analysis further shows that the two dominant parameters in rainfall estimation are the existence of cold cloud and the duration of cloud over a point

What Motivates a Leader?: A Grounded Theory Study of Hagberg, Maslow, and MAL Alumni

What motivates an individual to become a leader? Why do individuals want to influence and provide direction to others? What drives someone to be part of the leadership process? It is these questions that present the framework of this study. More specifically, this grounded theory study will analyze the factors that motivate an individual to become a leader based on: Janet Hagberg\u27s Leadership Model, the various writings of psychologist Abraham H. Maslow, and the data gathered from qualitative interviews with the Augsburg MAL Alumni. This study used the grounded theory research model for data collection, coding, logging, and analysis, as well as, to facilitate the discovery and emergence of patterns and themes. Six common patterns and themes emerged from the data of Maslow, Hagberg, and the MAL. One of the patterns, a Leadership Profile, emerged which details the characteristics and attributes of a leader, as well as, how leaders go about getting things done. Five additional patterns and themes - vision, purpose, relationships, curiosity, and creativity - emerged that provide insight into what motivates someone to be a leader