We present a model for the scaling of mixing in weakly rotating stratified flows characterized by their Rossby, Froude and Reynolds numbers $Ro,Fr$ , $Re$ . This model is based on quasi-equipartition between kinetic and potential modes, sub-dominant vertical velocity, $w$ , and lessening of the energy transfer to small scales as measured by a dissipation efficiency $\unicode[STIX]{x1D6FD}=\unicode[STIX]{x1D716}_{V}/\unicode[STIX]{x1D716}_{D}$ , with $\unicode[STIX]{x1D716}_{V}$ the kinetic energy dissipation and $\unicode[STIX]{x1D716}_{D}=u_{rms}^{3}/L_{int}$ its dimensional expression, with $w,u_{rms}$ the vertical and root mean square velocities, and $L_{int}$ the integral scale. We determine the domains of validity of such laws for a large numerical study of the unforced Boussinesq equations mostly on grids of $1024^{3}$ points, with $Ro/Fr\geqslant 2.5$ , and with $1600\leqslant Re\approx 5.4\times 10^{4}$ ; the Prandtl number is one, initial conditions are either isotropic and at large scale for the velocity and zero for the temperature $\unicode[STIX]{x1D703}$ , or in geostrophic balance. Three regimes in Froude number, as for stratified flows, are observed: dominant waves, eddy–wave interactions and strong turbulence. A wave–turbulence balance for the transfer time $\unicode[STIX]{x1D70F}_{tr}=N\unicode[STIX]{x1D70F}_{NL}^{2}$ , with $\unicode[STIX]{x1D70F}_{NL}=L_{int}/u_{rms}$ the turnover time and $N$ the Brunt–Väisälä frequency, leads to $\unicode[STIX]{x1D6FD}$ growing linearly with $Fr$ in the intermediate regime, with a saturation at $\unicode[STIX]{x1D6FD}\approx 0.3$ or more, depending on initial conditions for larger Froude numbers. The Ellison scale is also found to scale linearly with $Fr$ . The flux Richardson number $R_{f}=B_{f}/[B_{f}+\unicode[STIX]{x1D716}_{V}]$ , with $B_{f}=N\langle w\unicode[STIX]{x1D703}\rangle$ the buoyancy flux, transitions for approximately the same parameter values as for $\unicode[STIX]{x1D6FD}$ . These regimes for the present study are delimited by ${\mathcal{R}}_{B}=ReFr^{2}\approx 2$ and $R_{B}\approx 200$ . With $\unicode[STIX]{x1D6E4}_{f}=R_{f}/[1-R_{f}]$ the mixing efficiency, putting together the three relationships of the model allows for the prediction of the scaling $\unicode[STIX]{x1D6E4}_{f}\sim Fr^{-2}\sim {\mathcal{R}}_{B}^{-1}$ in the low and intermediate regimes for high $Re$ , whereas for higher Froude numbers, $\unicode[STIX]{x1D6E4}_{f}\sim {\mathcal{R}}_{B}^{-1/2}$ , a scaling already found in observations: as turbulence strengthens, $\unicode[STIX]{x1D6FD}\sim 1$ , $w\approx u_{rms}$ , and smaller buoyancy fluxes together correspond to a decoupling of velocity and temperature fluctuations, the latter becoming passive.

Late in the summer of 1993, Robert Hall, Chairman of the Department of Geology, Indiana University-Purdue University at Indianapolis (IUPUI) thought it would be a good idea to invite a couple of dinosaur workers to campus to capitalize on the frenzy of enthusiasm for dinosaurs that the movie, Jurassic Park, had generated. However, what originally was to have been a couple of guest lectures quickly evolved into a three-day affair that was probably the first scientific conference–certainly the first paleontologic conference–for the general public, raising important issues about public involvement in science.

The late Cenozoic history of mollusks in the tropical and subtropical Western Atlantic has traditionally been viewed as one of decreasing species richness via a series of more or less discrete extinction episodes, from a Mio-Pliocene peak to the depauperate (relative to the Eastern Pacific) fauna of today. These extinction episodes have been interpreted by some authors as responses to climatic deterioration, especially climatic cooling associated with northern hemisphere glaciation.

Two new species-level compilations of gastropods suggest, however, that this traditional scenario may be oversimplified.

1) A new (but still preliminary) compilation of species from the Late Pliocene “Pinecrest Sand” of southern Florida contains 365 species. This compilation is based mainly on specimens > 5mm in size taken from bulk samples collected in quarries near Sarasota and held in the collections of the Florida Museum of Natural History; when smaller specimens are considered, and systematic analysis of larger forms from this and other localities is complete, it is likely that this number will increase significantly. The Pinecrest has been systematically neglected; although our count is preliminary, it represents the most complete and well-documented compilation available for this spectacular and highly diverse fauna.

This number for the Pinecrest compares with 479 species of gastropods in the overlying Late Pliocene-Early Pleistocene Caloosahatchee “Formation” (data of Campbell et al., 1975). 178 gastropod species are in common between the two units, yielding an extinction level of 51.2%. 301 (62.8%) of the Caloosahatchee gastropod species are not present in the Pinecrest.

Stanley (1986) listed 211 species of bivalves in the Pinecrest and 150 in the Calooshatchee, with 110 in common, giving an extinction level of 47.9%. 40 (26.7%) of the Caloosahatchee bivalve species are not present in the Pinecrest.

2) A new compilation of all described Recent shelled gastropods in the Western Atlantic (Cape Hatteras to Rio de Janeiro) contains 2800 species (2418 of which were described before 1972), compared to the 2360 species listed by Keen (1971) for the Recent Eastern Pacific. These two lists compare similar size and depth ranges, and indicate that the Western Atlantic gastropod fauna is not less species-rich than the Eastern Pacific gastropod fauna.

In addition, a growing body of evidence from other studies (ostracodes, foraminifera, isotopic analyses) indicates that the Late Pliocene was not a time of marked climatic cooling, at least not in the Western Atlantic. Still other studies (e.g., of the biogeography of turritelline gastropods, isotopic analyses on both sides of the Central American Isthmus, paleoceanographic modelling) suggest that the most significant environmental changes at this time may have been associated with changes in nutrient levels.

Taken together, these very preliminary results suggest a more complex history for the Western Atlantic mollusk fauna than previously envisioned. If the Plio-Pleistocene was a time of significant turnover but not significant diversity decline, and gastropods of the Recent Western Atlantic are not less diverse than their Eastern Pacific counterparts, then the patterns to be explained must be reexamined. Late Cenozoic extinction may have been significant in the Western Atlantic, but it may have been accompanied by high levels of diversification.

In any case, those faunal changes that did occur at this time may have been caused as much or more by changes in nutrient levels as in temperature.

Growth rhythms are described in the accretionary skeletons of Rafinesquina alternata, a Late Ordovician brachiopod from southeastern Indiana. Contiguous growth increments widen and narrow in repeating series, giving the appearance of adjacent clusters of increments. Fourier analyses of growth increment widths and counts of the number of increments within individual clusters yield similar periodicities. Increments vary in width over a period of approximately 19 increments, modulated with a lower amplitude oscillation of 27 increments. The number of increments per cluster falls into two groups; clusters having between 8 and 17 increments outnumber those having between 18 and 30 increments.

All specimens were obtained from a Maysvillian facies of the Dillsboro Formation, previously inferred to represent a shallow subtidal environmental setting. The growth periodicities described here are consistent with this interpretation. The intensity of tidal parameters such as emersion-immersion cycles, substrate shifts, changes in nutrient supply or in oxygen tension declines with depth as would the number of growth increments added each month in response to these factors. Thus, for these specimens, the maximum number of increments per cluster probably approximates the true number of “tidal” days in the Late Ordovician synodic month (period between full moons).

The paleoecological model derived from these analyses can be used in future studies to predict the rate of the earth's rotation and the motion of the moon in the Late Ordovician and, equally importantly, to evaluate the limits of uncertainty of such studies.

The magnetized dusty plasma experiment (MDPX) is a newly commissioned plasma device that started operations in late spring, 2014. The research activities of this device are focused on the study of the physics, highly magnetized plasmas, and magnetized dusty plasmas. The design of the MDPX device is centered on two main components: an open bore, superconducting magnet that is designed to produce, in a steady state, both uniform magnetic fields up to 4 Tesla and non-uniform magnetic fields with gradients of 1–2 T m−1 and a flexible, removable, octagonal vacuum chamber that provides substantial probe and optical access to the plasma. This paper will provide a review of the design criteria for the MDPX device, a description of the research objectives, and brief discussion of the research opportunities offered by this multi-institution, multi-user project.

The Magnetized Dusty Plasma Experiment (MDPX) device is a newly constructed research instrument for the study of dusty (complex) plasmas. The MDPX device is envisioned as an experimental platform in which the dynamical behavior of all three charged plasma components, the electrons, ions, and charged microparticles (i.e., the ‘dust’) will be significantly influenced by the magnetic force. This brief paper will provide a short overview of the design, magnetic performance, and initial plasma measurements in the MDPX device.

We present numerical evidence of how three-dimensionalization occurs at small scale in rotating turbulence with Beltrami () forcing, creating helical flow. The Zeman scale at which the inertial and eddy turn-over times are equal is more than one order of magnitude larger than the dissipation scale, with the relevant domains (large-scale inverse cascade of energy, dual regime in the direct cascade of energy and helicity , and dissipation) each moderately resolved. These results stem from the analysis of a large direct numerical simulation on a grid of points, with Rossby and Reynolds numbers, respectively, equal to and . At scales smaller than the forcing, a helical wave-modulated inertial law for the energy and helicity spectra is followed beyond by Kolmogorov spectra for and . Looking at the two-dimensional slow manifold, we also show that the helicity spectrum breaks down at , a clear sign of recovery of three-dimensionality in the small scales.

The preparation of small, representative research samples of polymers for evaluation in the form of a fiber has been a continuing problem because of the several complex and interrelated steps in going from the monomer to the polymer to the fiber. Such complexity can be magnified in the preparation of rigid rod polymers like cis-PBO, i.e., poly[benzo(1,2-d:5,4-d')-bisoxazole-2,6-diyl-1,4-phenylene]. PBO is a member of the group of high performance polymers generically labeled the PBZ family. With these polymers the additional factors of unreliable mixing, high viscosity, varying morphology, poor solubility, extended polymerization times, etc., present formidable experimental problems. especially when only small quantities of monomers are available.

A new laboratory process has been developed to overcome the difficulties enumerated above so that a dehydrohalogenated monomer mixture in an appropriate solvent can be polymerized rapidly with molecular weight control. The polymer is degassed and otherwise conditioned for spinning, transferred to the spin pump with controlled morphological change, and subjected to dry-jet wet spinning to prepare a fiber representative of the polymer. The spinning operation incorporates features characteristic of both solution processing and thermoplastic extrusion.

Typical fibers of cis-PBO prepared by the process are described.

Microscopic morphologies of monocomponent and binary solids growing from melts and vapors are simulated with a Monte Carlo model that accounts for bulk diffusion, interface attachment and detachment kinetics and surface diffusion. The interplay between transport and interface kinetics on morphologies and its effect on microstructures including lamellar spacing, tilted lamellar and oscillatory structures is investigated. An important aspect of these models is the length scale of the simulation.

Preliminary characterization of two native insulators on germanium is reported. A technique for preparing oxide by a room temperature chemical technique (wet chemical oxidation) is described. Compositional data based on IR transmission and ellipsometry, as well as characteristics of MOS capacitors based on this film are given. Also, compositional and electrical characterization of nitrided atmospheric pressure oxides are reported here. These films have very low fixed charge and interface state densities, and show excellent potential for use as gate insulators in a germanium MOS technology.

Identification of polysilicate intermediates formed during sol-gel processing of silica gels and glasses is an important step toward understanding the nature of this process on a molecular level. Although capillary gas chromatography using mass spectrometric detection gives the molecular formulas for low molecular weight intermediates [1], this approach is only semi-quantitative and provides no structural information. An improved protocol has been developed that allows structural assignment and quantitative determination of the principal mono- through hexasilicate structural isamers formed by hydrolysis of methanolic tetramethylorthosilicate in the presence of HC1. This protocol combines quenching by diazomethane, fractionation using spinning band column distillation, identification by capillary gas chromatography, and structural characterization using 29Si{1H} NMR techniques (l-pulse, ID-INADEQUATE, and 2D-INADEQUATE) to provide structural assignments and response factors for the components separated by gas chromatography.