Giant scaphitid ammonites from the Maastrichtian of Europe

Giant scaphitid ammonites from the Maastrichtian of Europe have generally been assigned to Acanthoscaphites NOWAK, 1911. Prior to the present study, this genus comprised five species: A. tridens (KNER, 1848), A. varians (LOPUSKI, 1911), A. verneuilianus (D'ORBIGNY, 1841), A. sp. of KENNEDY (1987) and A. sp. of KENNEDY & CHRISTENSEN (1997). Of the first-named taxon, material from Aachen-Schneeberg of Early Maastrichtian age, including the specimen illustrated by HOLZAPFEL (1887-89) long thought to have been lost, is described. Recently collected topotype material from Kazimierz Dolny, and from Rejowiec (Poland), of latest Maastrichtian age (Belemnella kazimiroviensis Zone), allows A. varians to be revised. Specimens from the late Early and early Late Maastrichtian of NW Europe, assigned to A. varians, differ consistently in details of ornament, and are assigned to a new subspecies, A. v. blaszkiewiczi n. subsp. Style of ribbing and tuberculation of the varians stock differs from that of A. tridens to such an extent that a new subgenus, Euroscaphites n. subgen., is erected, with varians as type species. The Late Maastrichtian "Acanthoscaphites" verneuilianus, only known from phragmocones, is provisionally assigned to the new subgenus. The other two species previously referred to Acanthoscaphiles, viz. A. sp. of KENNEDY (1987) and A. sp. of KENNEDY & CHRISTENSEN (1997), both of Late Maastrichtian age, cannot be assigned confidently to either subgenus

Propagation of Laminar Flames in Wet Premixed Natural Gas-Air Mixtures

The present work investigates the effect of adding small amounts of humidity on the inhibition of natural gas-air flames. The inhibition is quantified by measuring and calculating the laminar burning velocities (Su) of premixed ames from a C1-C2 mechanism. The experimental apparatus consists of a Mache-Hebra burner, equipped with flow controllers and air purification system. Steam is generated by injecting water into a preheated natural gas-air stream, by means of a syringe pump. The burning velocities are determined experimentally from the schlieren photography using the total flame area.The results indicate decreasing burning velocities with increasing steam concentration, demonstrating the importance of thermal capacity of water vapour on slowing down the flame propagation. There is no indication of flame acceleration due to kinetic considerations, even when the flames are doped with minute moisture loadings. It is shown in the calculations that the laminar burning velocity depends strongly on the number of grid points, and so a scaling relationship is developed for adjusting the computed values of Su. The kinetic model predicts closely the experimental results, but the agreement between the experimental and numerical data is better at lower temperatures. The relationship between Su and the concentration of the added water vapour, as calculated from the model, is linear. For the natural gas considered in this work, the laminar burning velocity at the atmospheric pressure decreases by 1.81cm s-1 at 150°C for each percentage point of humidity present in the gas mixture, and by 1.18 cm s−1 at 20°C

BES3 time of flight monitoring system

A Time of Flight monitoring system has been developed for BES3. The light source is a 442-443 nm laser diode, which is stable and provides a pulse width as narrow as 50 ps and a peak power as large as 2.6 W. Two optical-fiber bundles with a total of 512 optical fibers, including spares, are used to distribute the light pulses to the Time of Flight counters. The design, operation, and performance of the system are described.Comment: 8 pages 16 figures, submitted to NI

Quantum Cascade Laser with Uni-Lateral Grating

We report on distributed feedback quantum cascade lasers at a wavelength of 3.58 μm operating at room temperature. Single-mode emission with a side-mode suppression ratio of 30 dB is achieved by manufacturing single-sided third-order lateral gratings. The devices exhibit watt level peak powers with a threshold current density of ~ 4.3 kA/cm2 at room temperature and remain in single-mode operation over the temperature range of 280-420 K

But what does it mean? Competition between products carrying alternative green labels when consumers are active acquirers of information

Programs that certify the environmental (or other social) attributes of firms are common. But the proliferation of labeling schemes makes it difficult for consumers to know what each one mean – what level of `greenness' does a particular label imply? We provide the first model in which consumers can expend effort to learn what labels mean. The relationship between information acquisition costs, firm pricing decisions, the market shares obtained by alternatively-labeled goods and a brown `backstop' good, and total environmental impact prove complex. Consumer informedness can have perverse implications. In plausible cases a reduction in the cost of information damages environmental outcomes. Our results challenge the presumption that provision of environmental information to the public is necessarily good for welfare or the environment

Seasonal and management influences on bacterial community structure in an upland grassland soil

Floristically diverse Nardo–Galion upland grasslands are common in Ireland and the UK and are valuable in agricultural, environmental and ecological terms. Under improvement (inputs of lime, fertiliser and re-seeding), they convert to mesotrophic grassland containing very few plant species. The effects of upland grassland improvement and seasonality on soil microbial communities were investigated at an upland site. Samples were taken at five times in one year in order to observe seasonal trends, and bacterial community structure was monitored using automated ribosomal intergenic spacer analysis (ARISA), a DNA-fingerprinting approach. Differences in soil chemistry and bacterial community structure between unimproved and improved grassland soils were noted. Season was also found to cause mild fluctuations in bacterial community structure, with soil samples from colder months (October and December) more correlated with change in ribotype profiles than samples from warmer months. However, for the majority of seasons clear differences in bacterial community structures from unimproved and improved soils could be seen, indicating seasonal influences did not obscure effects associated with improvement

Reperfusion in acute myocardial infarction

Studies of the pathophysiology of acute myocardial infarction (AMI) have shown that in most pa- tients a thrombus forms over a ruptured ather- oma in the infarct-related coronary artery and obstructs the artery

Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares

The extreme ultraviolet portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature and density sensitive line ratios, Doppler shifted emission lines and nonthermal broadening, abundance measurements, differential emission measure profiles, and continuum temperatures and energetics, among others. In this paper I shall review some of the advances made in recent years using these techniques, focusing primarily on studies that have utilized data from Hinode/EIS and SDO/EVE, while also providing some historical background and a summary of future spectroscopic instrumentation.Comment: 34 pages, 8 figures. Submitted to Solar Physics as part of the Topical Issue on Solar and Stellar Flare

Open tubular liquid-chromatography and the analysis of single neurons

Liquid chromatography in open tubular columns (OTLC) offers a means of achieving separations of high resolving power within analysis times of minutes to hours. A theory which predicts the optimal dimensions for an open tubular column for a given set of analytical conditions has been developed [1]. This theory predicts that for a wide range of possible inlet pressures and analysis times the most efficient columns will result when the column inner diameter is between 1.5 and 3 μm. A column of 2 μm diameter and 2 meter length should be capable of producing a million theoretical plates for an analyte with a capacity factor of 10 (strongly retained) and a retention time of 100 minutes