Correlation of lower Cambrian strata is often confounded by provincialism of key fauna. The widespread occurrence of the micromollusc Watsonella crosbyi Grabau, 1900 is therefore an important biostratigraphic signpost with potential for international correlation of lower Cambrian successions. Previous correlations of W. crosbyi from Australia (Normanville Group) suggested an Atdabanian- to Botoman-equivalent age. However, in the upper part of the Mount Terrible Formation, stratigraphic ranges of W. crosbyi and Aldanella sp. cf. golubevi overlap prior to the incoming of vertically burrowed ‘piperock’, which is indicative of an age no earlier than Cambrian Stage 2. The stratigraphic range of W. crosbyi in the Normanville Group, South Australia correlates with the ranges of the taxon in China, France, Mongolia and Siberia (though not Newfoundland). The new Australian data add further support for considering the first occurrence of W. crosbyi a good potential candidate for defining the base of Cambrian Stage 2. The stratigraphic range of W. crosbyi through the lower Cambrian Normanville Group has been determined based on collections from measured sections. Although rare, W. crosbyi is part of an assemblage of micromolluscs including Bemella sp., Parailsanella sp. cf. murenica and a sinistral form of Aldanella (A. sp. cf. A. golubevi). Other fauna present include Australohalkieria sp., Eremactis mawsoni, chancelloriids and Cupitheca sp.

A new species of Oikozetetes, O. mounti n. sp. is described from the upper Mernmerna Formation (equivalent to Cambrian Series 2) in the eastern Flinders Ranges, South Australia. Description of both shell morphotypes (morph A and B) from the same stratigraphic horizon favors the interpretation of a two-shelled scleritome for Oikozetetes. Identification of at least two types of halkieriid sclerite (palmates and siculates) in stratigraphic association with the Halkieria-like shells of Oikozetetes suggests that these elements are derived from the same scleritome. This provides evidence against previous suggestions that the Gondwanan species was aspiculate; the scleritome arrangement is interpreted to be similar to Halkieria evangelista Conway Morris and Peel, 1995 and supports placement in the family Halkieriidae Poulsen, 1967. Comparison of modes of accretionary growth in Oikozetetes shell morphotypes to Halkieria shells and terminal plates in modern polyplacophorans, supports a scleritome model that places shell morphs A and B in posterior and anterior locations, respectively, along the axis of the body.

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Exploration and extraction of natural gas from the Marcellus Shale have created considerable controversy. At the core of these debates are differing perceptions of the level and types of risks involved with the extraction activities, such as hydraulic fracturing, truck traffic, air emissions, and population growth. Risks described include the potential for human and environmental health implications, as well as community change and economic gain. This article explores the nature of perceived risks associated with Marcellus Shale development by using data from a household survey (N = 1,917) conducted in 2009–10 in Pennsylvania and New York counties located in the core areas of the Marcellus Shale region. The article describes a quantitative measure of risk perceptions. Statistical analyses of the data indicate that trust in institutions responsible for managing the risks associated with development and attitudes related to relationships between people and nature are associated strongly with perceptions of risk. Other associated variables include reported knowledge of environmental, social, and economic impacts, mineral rights ownership, demographic characteristics (gender, income), and state of residence. Implications of these findings are discussed, particularly as related to improving local discourse surrounding Marcellus Shale development.

Environmental Practice 15:108–122 (2013)

Development of unconventional natural gas resources in the Marcellus Shale region of the northeastern United States has progressed rapidly over the last decade. The discourse surrounding such development recalls quarter-century-old debates about positive and negative implications for the well-being of such energy boomtowns. Potential support or opposition relates to trust in the industry and its regulators, perceived knowledge, and perceived impacts. Our research project takes advantage of the opportunity for a natural experiment in comparing these elements between two spatially adjacent sites with contrasting approaches to gas development: in Pennsylvania, drilling of unconventional natural gas reserves has been proceeding for nearly a decade, whereas, at the time of this writing, drilling has not begun in New York. A mail survey of a random sample of New York and Pennsylvania residents within the Marcellus region revealed important differences between sites. New York residents were more opposed to development, characterized the industry in a more negative light, and were more likely to have engaged in various forms of public participation. In contrast, respondents did not differ by state on their perceived level of knowledge, even though gas development is more advanced in Pennsylvania. Potential explanations for these findings are offered, as are implications for understanding newly emerging energy boomtowns.

Environmental Practice 14:287–298 (2012)

We present here a new set of equations for modeling the I–V characteristics of Field Effects Transistors (FETs), particularly optimized for AlGaN/GaN HEMTs. These equations describe the whole characteristics from negative to positive breakdown loci, and reproduce the current saturation at high level. Using this model enables to decrease the modeling process duration when a same transistor topology is used for several applications in a T/R module. It can even be used for switches design, which is the most demanding application in terms of I–V swing. Moreover, particular care was taken to accurately model the first third orders of the current derivatives, which is important for multione applications. We also focused on an accurate definition of the nonlinear elements such as capacitances for power applications. There are 18 parameters for the main current source (and six for both diodes Igs and Igd). This can be compared to Tajima's equations-based model (13 parameters) or to the Angelov model (14 parameters), which only fit the I–V characteristics for positive values of Vds. We will detail here the model formulation, and show some measurements/modeling comparisons on both I–V, [S]-parameters and temporal load-pull obtained for a 8 × 75 μm GaN HEMT, with 0.25 μm gate length.

A method for phenetic analysis of karyotype data has been developed for Leishmania populations. Measurement of size difference between chromosomes recognized by a given DNA probe in different isolates led to the formulation of a Chromosome Size Difference Index (CSDI). The method was applied to phenetic analysis of 4 sets of chromosomes – each set being recognized by a different probe – in 37 L. (Viannia) peruviana isolates sampled along a North–South transect through the Peruvian Andes and, in 11 L. (V.) braziliensis isolates from the Amazonian forest (Peru, Bolivia and Brazil). Karyotype variability was better accounted for by CSDI than by a method based on disjunctive encoding of karyotype data. CSDI evidenced the nature of relationships between L. braziliensis and L. peruviana and it provided a coherent picture of geographical and genomic differentiation among parasite populations. The latter did cluster according to their geographical origin. L. braziliensis was found karyotypically more homogeneous than L. peruviana. Within L. peruviana, Northern populations were closer to L. braziliensis than to Southern L. peruviana populations. The validity of karyotypic populations, or karyodemes, was sustained.

The laser program developed at the Centre d'Etudes de Limeil-Valenton, Saint-Georges, France (CEL-V) is concentrated on a systematic investigation of indirect drive fusion; by comparison with direct drive, this process is expected to provide the required irradiation uniformity with relaxed constraints on laser beam quality. The main concerns are radiative transfer and preheat, hydrodynamic instabilities, and high-density X-ray driven implosions. Ablative implosion experiments have been conducted with the two beams at the Phebus facility (5 kJ, 1.3 ns, 0.35 μm). Symmetry was proved to be controlled by the casing structure, following scaling laws describing hohlraum physics. A compressed DT density ∼100 ρ0 (ρ0 liquid DT density) has been deduced from activation measurements. Different aspects of the soft X-ray transfer processes, and particularly of the ablation of a low-Z material, which drives the capsule implosion, are dealt with in detailed investigations. Reported here are results on X-ray reemission and penetration in several materials, and on induced hydrodynamics of accelerated foils. The laser energy required to reach fuel ignition conditions has been evaluated from numerical simulations as well as from analytical models, taking into account hohlraum physics, capsule implosion, hot spot formation, and burn propagation. Several crucial parameters have been drawn, the most important being the radiation temperature. A target gain in the order of 10 appears achievable with a 2-MJ laser.

Implosion experiments performed at Centre d'Etudes de Limeil-Valenton in the indirect drive scheme using the two-beams Nd:glass laser facility Phebus at the energy level = 6 kJ (blue light) are presented. A final density of compressed DT close to 100 ρ0 has been obtained; it has been deduced from radiochemistry of the activated silicon atoms in the pusher. The best irradiance uniformity on the microballoon was evaluated to = 15% rms. Phebus has also been equipped with an optical fiber oscillator to study the effect of a smoothing technique on coupling processes: It appeared that at 0·53 μm absorption efficiency is increased by =15–20%. With the eight-beams Octal laser, hydrodynamic instabilities development in accelerated planar targets has been investigated both for direct and indirect drives; the mixing zone detected at the light-heavy interface does not present visible bubble-and-spike like structures and is less developed in the indirect configuration. Atomic physics in laser plasmas is also deeply studied; a particular effort has been made on absorption spectroscopy, a powerful diagnostic of ionization dynamics in cold and dense plasmas. Experiments have been realized either in multilayered targets or using rear-side X-ray emission of thin Au foils to heat the samples. To reach fuel ignition conditions, more powerful lasers, in the range of megajoule, will be needed. Their design needs further technological developments to reduce the capital cost in $/W. At Limeil, we work mainly on high-damage threshold optical coatings, using the sol-gel process, high-quality, low-cost mirror fabrication, using the replica technics, and incoherent laser pulse generation for beam smoothing.

High power RF device performance decreases as operation temperature increases (e.g. decreasing electron mobility affects cut-off frequencies and degrades device reliability). Therefore determination of device temperature is a key issue for device topology optimisation. In this work the temperature variation of AlGaN/GaN high-electron-mobility transistors grown either on silicon or sapphire substrate under bias operation was measured by micro Raman scattering spectroscopy. Temperature measurements up to power dissipation of 16 W for 4 mm development devices were carried out and a peak temperature of 650 K was determined. The difference of thermal resistance for similar devices grown on the two different substrates was assessed. The thermal resistances of different device topologies were compared to optimise the component design.

The high power RF device performance decreases as the operation temperature increases (e.g. fall of electron mobility impacting the cut-off frequencies and degradation of device reliability). Therefore the determination of device temperature is a key issue for device topology optimisation. In this work the temperature variation of AlGaN/GaN high-electron-mobility transistors grown either on silicon or sapphire substrates under bias operation was measured by micro Raman scattering spectroscopy. The differences in thermal resistance for similar devices grown on the two different substrates were assessed. The thermal resistances of different device topologies were compared in order to optimise the component design. The temperature measurement across the gate and along the component fingers were made to quantify the thermal gradient of the device. Temperature measurement up to a power dissipation of 16 W for a 4 mm development device was carried out and the peak temperature of 650 K was determined.

The high power RF device performance decreases as operation temperature increases (e.g. fall of electron mobility impacting the cut-off frequencies and degradation of device reliability). Therefore the determination of device temperature is a key issue for device topology optimisation. This work presents the comparison between pulsed I-V at different temperature and DC measurements of AlGaN/GaN HEMTs grown on two different substrates: sapphire and silicon. This technique allows the determination of mean channel temperature and the device thermal resistance. The thermal resistance is a classical way to define the average channel temperature as a function of the dissipated power. In this work the thermal resistance ratio of the HEMT grown on sapphire compared to the one grown on silicon is found to be 1.7 instead of 3 as expected from straightforward thermal conductivity ratio. This lower difference is clearly attributed to the contribution of the GaN buffer layer.

The long bones of vertebrates, such as the tibiae and femurs of humans, extend in length by means of genotypic and phenotypic changes orchestrated by the chondrocytes comprising growth plate cartilage. Among the constituents synthesized by these cartilage cells, osteopontin (OPN), a phosphorylated glycoprotein, is thought to play a critical role in events leading to normal growth plate function and ultimate mineralization of the deeper zones of this cartilage region. The precise role of OPN, however, is uncertain with regard to mineralization, and present evidence supports the alternative possibilities that the protein may be either facilitative or inhibitory to mineral deposition. in order to investigate OPN function in a model growth plate, cartilage from normal 1-11 day old postnatal mice was examined by the novel techique of laser capture microdissection (LCM) followed by RT-PCR to obtain a measure of OPN gene expression by chondrocytes of known age and specific location in the plate. LCM permits identification of individual or clusters of cells within a tissue section and subsequent unique isolation (“capture”) of such cells for a variety of molecular analyses.

In this study, mouse tibiae were dissected, placed in RNAlater (Ambion, Austin, TX) to preserve message, and stored at −20°C. Sections (5 μm thick) of fresh frozen developing epiphyseal growth plates were obtained in a cryostat maintained at −20°C, fixed briefly in 70% ethanol, and stained with eosin. Sections were examined in a Pixcell LCM system (Arcturus Engineering, Mountain View, CA) where chondrocytes were attached to the surface of polymer film substrates and lifted free of sections. in separate experiments, ∼200-1200 cells were captured and analyzed. Substrates were transferred to Eppendorf tubes containing RNA extraction buffer. RNA was extracted from cells by microisolation (Stratagene, La Jolla, CA), DNAse-treated, reverse-transcribed, and then subjected to PCR (40 cycles) with AmpliTaq DNA polymerase (PE Applied Biosystems, Foster City, CA). Ethidium bromide agarose gels revealed OPN mRNA from groups of chondrocytes isolated from whole cartilage and from resting, proliferating, and hypertrophic growth plate zones from the mouse tibiae. Brain cells captured by LCM from the same mouse sections served as positive controls and reactions containing no reverse transcriptase were negative controls. 18S rRNA was used as a marker for semiquantitation and standardization of expressed message from captured cells.

An experiment has been performed with the LULI Multi-TeraWatt Laser. The acceleration of electrons injected in a plasma wave generated by the laser wakefield mechanism has been observed with a maximum energy gain of 1.5 MeV. It has been shown that the electrons deflected during the interaction, could scatter on the walls of the experimental chamber, and fake a high-energy signal. A special effort has been given in the electron detection to separate the accelerated electrons signal from the background noise.The experimental results agree with theoretical predictions and numerical simulations when 3D effects on the electron beam are taken into account.

This paper presents the results of analyses and measurements performed on an active glass sample taken from the French vitrification facility R7.