bluuebunny/crossref_metadata_2025 huggingface dataset:
MYCENAE REVISITED PART 4: ASSESSING THE NEW DATA
Authors: Dickinson O.T.P.K. , Papazoglou-Manioudaki Lena , Nafplioti Argyro , Prag A.J.N.W.
Published: August 2012

This is the fourth and final part of the series inspired by the rediscovery in 2003 of two skeletons excavated in 1877 in Shaft Grave VI in Circle A at Mycenae by Panayiotis Stamatakis. The contribution of Stamatakis to the excavations, the discrepancies between his unpublished reports to the Archaeological Society and Schliemann's account, and the reliability of that account, are discussed. This is followed by a survey of what can now be said about Grave Circle A, following the restudy of the surviving bones from Graves III–VI and the publication of various details of the arrangement in the graves reported by Stamatakis, and by a final somewhat speculative discussion of what the graves contribute to the study of the development of Mycenae at the time of its rapid rise to prominence and the accompanying major changes in the structure of society, at Mycenae and elsewhere on the Greek mainland.
Sunshine, rainfall, humidity and child pneumonia in the tropics: time-series analyses
Authors: PAYNTER S. , WEINSTEIN P. , WARE R. S. , LUCERO M. G. , TALLO V. , NOHYNEK H. , BARNETT A. G. , SKELLY C. , SIMÕES E. A. F. , SLY P. D. , WILLIAMS G. ,   the ARIVAC Consortium
Published: August 2012

Few studies have formally examined the relationship between meteorological factors and the incidence of child pneumonia in the tropics, despite the fact that most child pneumonia deaths occur there. We examined the association between four meteorological exposures (rainy days, sunshine, relative humidity, temperature) and the incidence of clinical pneumonia in young children in the Philippines using three time-series methods: correlation of seasonal patterns, distributed lag regression, and case-crossover. Lack of sunshine was most strongly associated with pneumonia in both lagged regression [overall relative risk over the following 60 days for a 1-h increase in sunshine per day was 0·67 (95% confidence interval (CI) 0·51–0·87)] and case-crossover analysis [odds ratio for a 1-h increase in mean daily sunshine 8–14 days earlier was 0·95 (95% CI 0·91–1·00)]. This association is well known in temperate settings but has not been noted previously in the tropics. Further research to assess causality is needed.
WHAT A DIFFERENCE A SUM (∑) MAKES: SUCCESS AND FAILURE IN THE RATIONALIZATION OF DEMAND
Authors: HANDS D. WADE
Published: August 2012

This paper discusses the Sonnenschein–Mantel–Debreu (SMD) theorems in general equilibrium theory. It argues that the SMD results were related to the previous literature on the integrability of demand. The integrability question involved rationalizing individual demand functions, and the SMD theorems asked the same question about aggregate (market) excess demand functions. The paper’s two goals are to demonstrate how the SMD results followed naturally from the earlier work on integrability, and to point out that the profession’s reception was quite different; the integrability results were considered a success story, while the SMD results were quite negative.
Familial intergenerational and maternal aggregation patterns in nutrient intakes in the Lifeways Cross-Generation Cohort Study
Authors: Shrivastava Aakash , Murrin Celine , Sweeney Mary Rose , Heavey Patricia , Kelleher Cecily C
Published: August 2012

Objective

The current study prospectively examines the intra-uterine hypothesis by comparing maternal, paternal and grandparental lineage influences on children's diet and also maternal–child aggregation patterns during pregnancy and early childhood.

Design

Prenatal dietary information was available for expectant mothers, fathers and up to four grandparents through a detailed validated semi-quantitative FFQ. At 6-year follow-up, when children averaged 5 years of age, dietary information was re-collected for mothers and a subset of maternal grandmothers using the same FFQ. Child's FFQ version was used for children. Anthropometric and sociodemographic variables were also collected.

Settings

Three-generation familial cohort representative of the contemporary Irish national population.

Subjects

Children aged 5 years (n 567) and their parents and grandparents.

Results

Associations for energy, macronutrient and fibre intakes were compared using Pearson's correlations, intra-class correlations (ICC) and linear regression models, adjusted for energy and potential confounders. Significant, moderate-strength positive correlations were observed for nutrient intakes in children's nuclear families (ICC (range) = 0·22–0·28). The father–child associations (r (range) = 0·13–0·20) were weaker than the mother–child associations (r (range) = 0·14–0·33). In general, associations were stronger for maternal postnatal intake–child intake than for maternal prenatal intake–child intake, except for percentage of energy from fat (adjusted β = 0·16, 95 % CI 0·05, 0·26; P = 0·004), which was stronger for maternal prenatal intake, specifically in non-breast-fed children (adjusted β = 0·28, 95 % CI 0·12, 0·44; P = 0·001). Among all grandparents, correlations were significant only for maternal grandmother–mother pairs (r (range) = 0·10–0·36). Significant positive ICC were observed for nutrient intakes of maternal grandmother–mother–child triads (ICC (range) = 0·12–0·27), not found in paternal lines.

Conclusions

These findings suggest that maternal-environment programming influences dietary intake.
“Fun, Yes, but Music?” Steve Reich and the San Francisco Bay Area's Cultural Nexus, 1962–65
Authors: COLE ROSS
Published: August 2012

This article traces Steve Reich through the Bay Area's cultural nexus during the period 1962–65, exploring intersections with Luciano Berio, Phil Lesh, Terry Riley, Robert Nelson, the San Francisco Mime Troupe, and the San Francisco Tape Music Center. The aim is to present a revised history of this era by drawing on personal interviews with Tom Constanten, R. G. Davis, Jon Gibson, Saul Landau, Pauline Oliveros, and Ramon Sender. In addition, previously unused source materials and contemporaneous newspaper reception are employed to provide a more nuanced contextual framework. Reich's heterogeneous activities—ranging from “third stream” music and multimedia happenings to incidental scores and tape collage—deserve investigation on their own terms, rather than from within narratives concerned with the stylistic development of “minimalism.” More appropriate and viable aesthetic parallels are drawn between Reich's work for tape and Californian Funk art.
Comment on “Ocean mass from GRACE and glacial isostatic adjustment” by D. P. Chambers et al.
Authors: Peltier W. R. , Drummond R. , Roy K.
Published: August 2012

The modern global theory of the glacial isostatic adjustment (GIA) process is a theory that directly addresses the extent to which the geoid of classical geodesy is impacted by this phenomenon. Because the geoid is, by conventional definition, the surface of constant potential that overlaps the surface of the sea in the absence of currents and tides, we may determine the impact of the GIA process upon it only by explicit analysis of the manner in which mass is redistributed among the ocean basins and the level of the sea is thereby influenced. Although the dominant contribution to GIA is that associated with the transfer of mass between the oceans and the continents, there is an additional influence due to the variations in Earth's rotational state. This influence “feeds‐back” onto the geoid. In the recent paper by Chambers et al. (2010), several arguments were presented that question earlier attempts to discuss the consequences of this feedback. These arguments are interesting and we address them in what follows.
After dramatic landing, Mars Curiosity rover will soon search for signs of habitability
Authors: Showstack Randy
Published: August 2012

It was a beautiful day to begin a search for evidence of habitability on another planet. With an earlier nearby dust storm having dissipated, NASA's Mars Science Laboratory (MSL) spacecraft, carrying the Curiosity rover (also known as the MSL rover), completed a complex, daring, and perfectly executed descent through the Martian atmosphere to the planet's surface on 5 August. During the final 7‐minute descent period, with a time delay in receiving signals on Earth, the spacecraft's computer executed risky maneuvers, including guided entry and parachute deployment. Twenty meters above the surface, the instrument‐laden, 899‐kilogram Mars Curiosity rover was lowered flawlessly on nylon tethers from an innovative “sky crane” on the descent stage rocket.
Comments on USGS draft science strategies
Authors: Showstack Randy
Published: August 2012

The U.S. Geological Survey (USGS) is seeking comments on a number of the agency's draft 10‐year science strategies, including those for USGS core science systems, energy and minerals, environmental health, ecosystems, natural hazards, and water. The deadline for providing comments is 1 September. To review and comment on the draft strategies, see http://www.usgs.gov/start_with_science/index.php.
Nominations sought for extractive industries committee
Authors: Showstack Randy
Published: August 2012

U.S. secretary of the Interior Ken Salazar announced on 26 July the establishment of a national committee to guide U.S. implementation of the Extractive Industries Transparency Initiative. The Interior Department is seeking nominations of people interested in serving on the committee, which will be convened as a new federal advisory group. The initiative calls on governments to publicly disclose revenues from oil, gas, and mining assets and for companies to make disclosures about payments. U.S. president Barack Obama announced the commitment of the United States to participate in this initiative as part of the U.S. National Action Plan for the International Open Government Partnership.
Arctic region mapping tool
Authors: Showstack Randy
Published: August 2012

An interactive online mapping tool is now available to assist with scientific, environmental, and emergency response needs in the Arctic region, the National Oceanic and Atmospheric Administration (NOAA) announced on 31 July. The Environmental Response Management Application (ERMA®) already has been used in other regions, including in the Gulf of Mexico, as part of the response to the Deepwater Horizon oil spill in 2010. The tool—which is a product of the combined work of NOAA, the U.S. Department of the Interior's Bureau of Safety and Environmental Enforcement (BSEE), the University of New Hampshire, and others—offers near–real time oceanographic observations, weather data, environmental and commercial information, and other data.
Atmospheric moisture residence time affects rainwater isotope ratios
Authors: Bhattacharya Atreyee
Published: August 2012

The water cycle is expected to respond to rising air temperature, which redistributes moisture in the lowest part of the atmosphere, known as the boundary layer. To understand how boundary layer processes redistribute rainfall across different climate settings, climatologists use stable isotope ratios of oxygen and hydrogen in rainwater. A process known as Rayleigh fractionation—which depends on air temperature and amount of rainfall among other factors—controls the stable isotope makeup of rainwater. For example, in the tropics the isotope ratio depends on the amount of rainfall, whereas in high‐latitude continents it depends on the air temperature.
Remote sensing of hydrological connectivity
Authors: Schultz Colin
Published: August 2012

The sub‐surface flow of water within a watershed is traditionally thought to depend solely on topographic or physical influences, such as slope, soil permeability, and channel density. Though often overlooked, some researchers propose that the role of vegetation and its feedback on subsurface flow could be just as important in some cases. Plants tend to increase subsurface flow by increasing soil conductivity and preferential flow paths. They can also cause it to decline, as plants use subsurface water and nutrients to fuel their growth, drawing it out of the system through evapotranspiration. Both sets of feedbacks affect the downslope availability of water. To capitalize on this idea, Hwang et al. devised a system called the hydrological vegetation gradient (HVG).
Inertial currents in the Caspian Sea
Authors: Farley Nicholls J. , Toumi R. , Budgell W. P.
Published: August 2012

We present the first simulation of near‐inertial oscillations in the Caspian Sea. Model amplitude is in good agreement with observations. Annual mean near‐inertial oscillations are found to be up to 14 cm/s with a seasonal maximum in the summer approximately twice as great as in the winter. The energy increases away from the coast at a rate of up to 0.8 cm2 s−2 km−1; the strongest relationship is with distance from the 50 m depth contour. The peak amplitude also occurs later further from the coastline with a delay of the order of 1 day per 100 km distance. These features are consistent with propagating baroclinic and barotropic waves.
Fast strontium transport induced by hydrodynamic dispersion and pH‐dependent sorption
Authors: Prigiobbe Valentina , Hesse Marc A. , Bryant Steven L.
Published: August 2012

As a fluid carries solutes through a porous material, species that sorb onto the surface of the material travel more slowly than the fluid. Stronger adsorption results in slower solute migration, or increased solute retardation. The adsorption of strontium (Sr2+) onto iron‐oxides is strongly pH‐dependent and becomes significant at high pH. Radioactive Sr2+isotopes are, therefore, commonly stored in alkaline solutions to maximize their retardation. Field observations and numerical simulations of the leakage of such solutions into low‐pH soils, however, show that even Sr2+ stored in alkaline solutions can migrate without retardation. Migration occurs because hydrodynamic dispersion allows mixing of Sr2+with the low‐pH fluid forming an acidic Sr2+‐rich plume which can travel without retardation. Here we report the first experimental observations confirming this dispersion‐induced fast Sr2+transport. We report column‐flood experiments where a high‐pH solution containing Sr2+was injected into a low‐pH porous medium of iron‐oxide‐coated beads. We observe both a strongly retarded Sr2+ front and an isolated fast pulse of Sr2+traveling at the average fluid velocity. This dispersion‐induced fast pulse of strontium must be taken into account when considering the safety of radionuclide storage in alkaline solutions.
On the altitude of the ELF/VLF source region generated during “beat‐wave” HF heating experiments
Authors: Moore R. C. , Fujimaru S. , Cohen M. , Gołkowski M. , McCarrick M. J.
Published: August 2012

Modulated high frequency (HF, 3–10 MHz) heating of the ionosphere in the presence of the auroral electrojet currents is an effective method for generating extremely low frequency (ELF, 3–3000 Hz) and very low frequency (VLF, 3–30 kHz) radio waves. The amplitudes of ELF/VLF waves generated in this manner depend sensitively on the auroral electrojet current strength, which varies with time. In an effort to improve the reliability of ELF/VLF wave generation by ionospheric heating, recent experiments at the High‐frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska, have focused on methods that are independent of the strength of the auroral electrojet currents. One such potential method is so‐called “beat‐wave” ELF/VLF generation. Recent experimental observations have been presented to suggest that in the absence of a significantD‐region ionosphere (∼60–100 km altitude), an ELF/VLF source region can be created within theF‐region ionosphere (∼150–250 km altitude). In this paper, we use a time‐of‐arrival analysis technique to provide direct experimental evidence that the beat‐wave source region is located in theD‐region ionosphere, and possibly the lowerE‐region ionosphere (∼100–120 km altitude), even when ionospheric diagnostics indicate a very weakD‐layer. These results have a tremendous impact on the interpretation of recent experimental observations.
Coupled atmosphere‐ocean‐wave simulations of a storm event over the Gulf of Lion and Balearic Sea
Authors: Renault Lionel , Chiggiato Jacopo , Warner John C. , Gomez Marta , Vizoso Guillermo , Tintoré Joaquin
Published: August 2012

The coastal areas of the North‐Western Mediterranean Sea are one of the most challenging places for ocean forecasting. This region is exposed to severe storms events that are of short duration. During these events, significant air‐sea interactions, strong winds and large sea‐state can have catastrophic consequences in the coastal areas. To investigate these air‐sea interactions and the oceanic response to such events, we implemented the Coupled Ocean‐Atmosphere‐Wave‐Sediment Transport Modeling System simulating a severe storm in the Mediterranean Sea that occurred in May 2010. During this event, wind speed reached up to 25 m.s−1inducing significant sea surface cooling (up to 2°C) over the Gulf of Lion (GoL) and along the storm track, and generating surface waves with a significant height of 6 m. It is shown that the event, associated with a cyclogenesis between the Balearic Islands and the GoL, is relatively well reproduced by the coupled system. A surface heat budget analysis showed that ocean vertical mixing was a major contributor to the cooling tendency along the storm track and in the GoL where turbulent heat fluxes also played an important role. Sensitivity experiments on the ocean‐atmosphere coupling suggested that the coupled system is sensitive to the momentum flux parameterization as well as air‐sea and air‐wave coupling. Comparisons with available atmospheric and oceanic observations showed that the use of the fully coupled system provides the most skillful simulation, illustrating the benefit of using a fully coupled ocean‐atmosphere–wave model for the assessment of these storm events.
Mechanisms of decadal sea level variability in the eastern North Atlantic and the Mediterranean Sea
Authors: Calafat F. M. , Chambers D. P. , Tsimplis M. N.
Published: August 2012

Decadal sea level variations from tide gauge records along the western European coast and in the Mediterranean Sea commencing in the late 19th and early 20th centuries are examined relative to large‐scale atmospheric forcing. Recent studies have provided evidence for a link between sea level in the eastern North Atlantic and atmospheric forcing, however the nature of this relationship is still unclear. Here the outputs of a regional barotropic model and a nearly global baroclinic model are used in conjunction with wind stress and heat flux data to explore the physical mechanisms responsible for the observed sea level variability. All tide gauge records show significant decadal variability (up to 15 cm) and are highly correlated with the NAO and among themselves at decadal periods. There is a coherent sea level signal that affects the eastern boundary of the North Atlantic northward of 25°N and is limited to a narrow band of the order of a few hundred kilometers along the coast. This band tends to become narrower towards higher latitudes. We find that longshore wind and wave propagation along the boundary are the major contributors to coastal sea level variability but no significant contribution from mass redistribution linked to changes in the strength of the subtropical gyre is observed. The mass component dominates sea level in the Mediterranean and is mainly driven by mass exchanges with the Atlantic, which explains the correlation between both regions. Southward of 25°N, sea level changes are mainly driven by heat advection through Ekman fluxes.
Design of membrane targeting tobramycin-based cationic amphiphiles with reduced hemolytic activity
Authors: Herzog Ido M. , Feldman Mark , Eldar-Boock Anat , Satchi-Fainaro Ronit , Fridman Micha
Published: August 2012

Hemolysis caused by amphiphilic tobramycin antimicrobial agents is significantly reduced by altering the bond linking their hydrophobic and hydrophilic parts.
Discovery of hydroxamate bioisosteres as KAT II inhibitors with improved oral bioavailability and pharmacokinetics
Authors: Henderson Jaclyn L. , Sawant-Basak Aarti , Tuttle Jamison B. , Dounay Amy B. , McAllister Laura A. , Pandit Jayvardhan , Rong Suobao , Hou Xinjun , Bechle Bruce M. , Kim Ji-Young , Parikh Vinod , Ghosh Somraj , Evrard Edelweiss , Zawadzke Laura E. , Salafia Michelle A. , Rago Brian , Obach Ronald S. , Clark Alan , Fonseca Kari R. , Chang Cheng , Verhoest Patrick R.
Published: August 2012

A series of kynurenine aminotransferase II (KAT II) inhibitors has been developed replacing the hydroxamate motif with a bioisostere.
Structure–activity relationship studies of miniproteins targeting the androgen receptor–coactivator interaction
Authors: Seoane Marta Dominguez , Petkau-Milroy Katja , Vaz Belen , Möcklinghoff Sabine , Folkertsma Simon , Milroy Lech-Gustav , Brunsveld Luc
Published: August 2012

Miniproteins featuring a stable α-helical motif allow exploring point mutations in and around FXXLF motifs to improve androgen receptor affinity.
The design and synthesis of 5- and 6-isoxazolylbenzimidazoles as selective inhibitors of the BET bromodomains
Authors: Hay Duncan , Fedorov Oleg , Filippakopoulos Panagis , Martin Sarah , Philpott Martin , Picaud Sarah , Hewings David S. , Uttakar Sagar , Heightman Tom D. , Conway Stuart J. , Knapp Stefan , Brennan Paul E.
Published: August 2012

Simple 1-substituted 5- and 6-isoxazolyl-benzimidazoles have been shown to be potent inhibitors of the BET bromodomains with selectivity over the related bromodomain of CBP.
The status of type I polyketide synthase ketoreductases
Authors: Zheng Jianting , Keatinge-Clay Adrian T.
Published: August 2012

The functional dissection of type I polyketide synthases has established that ketoreductases most commonly set the orientations of the hydroxyl and alkyl substituents of complex polyketides. Here we review the biochemical, structural biology, and engineering studies that have helped elucidate how stereocontrol is enforced by these enzymes.
Density functional theory for Yukawa fluids
Authors: Hatlo Marius M. , Banerjee Priyanka , Forsman Jan , Lue Leo
Published: August 2012

We develop an approximate field theory for particles interacting with a generalized Yukawa potential. This theory improves and extends a previous splitting field theory, originally developed for counterions around a fixed charge distribution. The resulting theory bridges between the second virial approximation, which is accurate at low particle densities, and the mean-field approximation, accurate at high densities. We apply this theory to charged, screened ions in bulk solution, modeled to interact with a Yukawa potential; the theory is able to accurately reproduce the thermodynamic properties of the system over a broad range of conditions. The theory is also applied to “dressed counterions,” interacting with a screened electrostatic potential, contained between charged plates. It is found to work well from the weak coupling to the strong coupling limits. The theory is able to reproduce the counterion profiles and force curves for closed and open systems obtained from Monte Carlo simulations.
Dynamic homotopy and landscape dynamical set topology in quantum control
Authors: Dominy Jason , Rabitz Herschel
Published: August 2012

We examine the topology of the subset of controls taking a given initial state to a given final state in quantum control, where “state” may mean a pure state |ψ⟩, an ensemble density matrix ρ, or a unitary propagator U(0, T). The analysis consists in showing that the endpoint map acting on control space is a Hurewicz fibration for a large class of affine control systems with vector controls. Exploiting the resulting fibration sequence and the long exact sequence of basepoint-preserving homotopy classes of maps, we show that the indicated subset of controls is homotopy equivalent to the loopspace of the state manifold. This not only allows us to understand the connectedness of “dynamical sets” realized as preimages of subsets of the state space through this endpoint map, but also provides a wealth of additional topological information about such subsets of control space.
Kinetic lattice Monte Carlo simulation of viscoelastic subdiffusion
Authors: Fritsch Christian C. , Langowski Jörg
Published: August 2012

We propose a kinetic Monte Carlo method for the simulation of subdiffusive random walks on a Cartesian lattice. The random walkers are subject to viscoelastic forces which we compute from their individual trajectories via the fractional Langevin equation. At every step the walkers move by one lattice unit, which makes them differ essentially from continuous time random walks, where the subdiffusive behavior is induced by random waiting. To enable computationally inexpensive simulations with n-step memories, we use an approximation of the memory and the memory kernel functions with a complexity \documentclass[12pt]{minimal}\begin{document}$\mathcal {O}(\log n)$\end{document}O(logn). Eventual discretization and approximation artifacts are compensated with numerical adjustments of the memory kernel functions. We verify with a number of analyses that this new method provides binary fractional random walks that are fully consistent with the theory of fractional Brownian motion.
The effects of nonthermal electron distributions on ion-temperature-gradient driven drift-wave instabilities in electron-ion plasma
Authors: Batool Nazia , Masood W. , Mirza Arshad M.
Published: August 2012

The effects of nonthermal electron distributions on electrostatic ion-temperature-gradient (ITG) driven drift-wave instabilities in the presence of equilibrium density, temperature, and magnetic field gradients are investigated here. By using Braginskii’s transport equations for ions and Cairns as well as Kappa distribution for electrons, the coupled mode equations are derived. The modified ITG driven modes are derived, and it is found both analytically as well as numerically that the nonthermal distribution of electrons significantly modify the real frequencies as well as the growth rate of the ITG driven drift wave instability. The growth rate of ion-temperature-gradient driven instability is found to be maximum for Cairns, intermediate for Kappa, and minimum for the Maxwellian distributed electron case. The results of present investigation might be helpful to understand several wave phenomena in space and laboratory plasmas in the presence of nonthermal electrons.
Structure and anomalous solubility for hard spheres in an associating lattice gas model
Authors: Szortyka Marcia M. , Girardi Mauricio , Henriques Vera B. , Barbosa Marcia C.
Published: August 2012

In this paper we investigate the solubility of a hard-sphere gas in a solvent modeled as an associating lattice gas. The solution phase diagram for solute at 5% is compared with the phase diagram of the original solute free model. Model properties are investigated both through Monte Carlo simulations and a cluster approximation. The model solubility is computed via simulations and is shown to exhibit a minimum as a function of temperature. The line of minimum solubility (TmS) coincides with the line of maximum density (TMD) for different solvent chemical potentials, in accordance with the literature on continuous realistic models and on the “cavity” picture.
On the lifetime of plasmonic transducers in heat assisted magnetic recording
Authors: Budaev Bair V. , Bogy David B.
Published: August 2012

For a heat assisted magnetic recording system to be successful, it must deliver heat to a small spot on a magnetic disk without being damaged by the applied power. This paper shows that such conditions may not be easily attained in systems that use laser energy and plasmonic near field transducers. It is also shown that the analysis and design of the near field transducers cannot rely on numerical integration of the conventional Maxwell equations of electrodynamics of continuous media, because such equations implicitly incorporate numerous assumptions that are not valid in nanoscale systems. Here, we examine assumptions inherent in the derivation of these equations and point out which assumptions are violated if they are applied to the metallic nanoscale elements of heat assisted magnetic recording systems. The main body of the paper focuses on the well-known experimental results that support our conclusions while the derivations are relegated to the appendices.
Surface-plasmon-like modes of graphite powder compact in microwave heating
Authors: Kashimura K. , Suzuki S. , Hayashi M. , Mitani T. , Shinohara N. , Nagata K.
Published: August 2012

We determine the mechanism of rapid and selective heating of nonmagnetic conductive particles by the electric and magnetic fields of microwaves. We investigated the dependencies of the heating behaviors of carbon powders on the radius and electrical conductivity for various relative densities. In these experiments, strong microwave absorption was observed in magnetic field at certain radii and ratios of the crystallite size to the radius. Mie theory for a single particle could account for the high heating rates generated by the microwave magnetic field in sintering experiments. In the dependence of the heating behavior on the relative density, that H field exhibited the maximum absorption at certain relative densities of the graphite powders. These surface plasmon-like modes were observed in graphite, but were not observed when an E field was applied. Multiparticle systems such as graphite powder were found to have significantly different heating behaviors from a single particle. Microwave heating of metal particles is expected to be affected by the structure and shape of the particles.
Swellable elastomers under constraint
Authors: Lou Yucun , Robisson Agathe , Cai Shengqiang , Suo Zhigang
Published: August 2012

Swellable elastomers are widely used in the oilfield to seal the flow of downhole fluids. For example, when a crack appears in self-healing cement, the liquid in the surroundings flows into the crack and permeates into the cement, causing small particles of elastomers in the cement to swell, resulting in the blocking of the flow. Elastomers are also used as large components in swellable packers, which can swell and seal zones in the borehole. In these applications, the elastomers swell against the constraint of stiff materials, such as cement, metal, and rock. The pressure generated by the elastomer against the confinement is a key factor that affects the quality of the sealing. This work develops a systematic approach to predict the magnitude of the pressure in such components. Experiments are carried out to determine the stress-stretch curve, free swelling ratio, and confining pressure. The data are interpreted in terms of a modified Flory-Rehner model.
Impact of Xe partial pressure on the production of excimer vacuum ultraviolet emission for plasma display panels
Authors: Zhu Di , Zhang Xiong , Kajiyama Hiroshi
Published: August 2012

In this work, the effect of the Xe partial pressure on the excimer vacuum ultraviolet (VUV) emission intensity of the plasma display panels is investigated, both by measuring the spectral emission directly and by two-dimensional simulations. Experimentally, we find that at the high Xe partial pressure levels, there is an supra-linear increase of excimer VUV radiation and that determines the strong increase of luminance at the high pressures and high voltage. Due to the increase of the luminance and the almost unchanged discharge current, the luminous efficacy strongly increases with the Xe partial pressure. In addition, we also investigated the dynamics of the VUV generation, by measuring the decay time of the excimer VUV light as a function of the gas pressure. It is found that the decay time decreases with the increase of gas pressure. The spatial characteristics of the excimer VUV emission are also discussed. Different from the Ne and near-infrared emission, the excimer VUV emission is generated near the surface of the electrodes and increases uniformly on both sides of the anode and cathode (i.e., the bulk plasma region). Most importantly, it is found that the VUV production occurs during the afterglow period, while it is almost zero at the moment of the discharge itself. From the simulations, it can be seen that the Xe2*(3Σu+) excimer species, which are generated from Xe*(1s5), play a dominant role in the excimer VUV emission output at the high Xe partial pressure. The two-dimensional simulations also show that the strong increase of Xe excimer excitation states in the case of high pressure is mainly the result of the high conversion efficiency of the Xe excimer states, especially in the afterglow period. Due to the high conversion efficiency of Xe excitation species to Xe excimer species by the high collision rate in the case of high pressure, there is a strong increase of excimer VUV production, especially from the cathode.
Normal metal-superconductor decoupling as a source of thermal fluctuation noise in transition-edge sensors
Authors: Kinnunen K. M. , Palosaari M. R. J. , Maasilta I. J.
Published: August 2012

We have studied the origin of excess noise in superconducting transition-edge sensors (TES) with several different detector designs. We show that most of the observed noise and complex impedance features can be explained by a thermal model consisting of three bodies. We suggest that one of the thermal blocks and the corresponding thermal fluctuation noise arise due to the high-frequency thermal decoupling of the normal and superconducting phase regions inside the TES film. Our results are also consistent with the prediction that in thin bilayer proximitized superconductors, the jump in heat capacity at the critical temperature is smaller than the universal BCS theory result.
Multi-keV x-ray sources from metal-lined cylindrical hohlraums
Authors: Jacquet L. , Girard F. , Primout M. , Villette B. , Stemmler Ph.
Published: August 2012

As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are ∼6%-8% for titanium, ∼2% for copper, and ∼0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.
Quantification of the specific membrane capacitance of single cells using a microfluidic device and impedance spectroscopy measurement
Authors: Tan Qingyuan , Ferrier Graham A. , Chen Brandon K. , Wang Chen , Sun Yu
Published: August 2012

The specific membrane capacitance (SMC) is an electrical parameter that correlates with both the electrical activity and morphology of the plasma membrane, which are physiological markers for cellular phenotype and health. We have developed a microfluidic device that enables impedance spectroscopy measurements of the SMC of single biological cells. Impedance spectra induced by single cells aspirated into the device are captured over a moderate frequency range (5 kHz–1 MHz). Maximum impedance sensitivity is achieved using a tapered microfluidic channel, which effectively routes electric fields across the cell membranes. The SMC is extracted by curve-fitting impedance spectra to an equivalent circuit model. From our measurement, acute myeloid leukemia (AML) cells are found to exhibit larger SMC values in hypertonic solutions as compared with those in isotonic solutions. In addition, AML cell phenotypes (AML2 and NB4) exhibiting varying metastatic potential yield distinct SMC values (AML2: 16.9 ± 1.9 mF/m2 (n = 23); NB4: 22.5 ± 4.7 mF/m2 (n = 23)). Three-dimensional finite element simulations of the microfluidic device confirm the feasibility of this approach.
Role of mucilage in seed dispersal and germination of the annual ephemeral Alyssum minus (Brassicaceae)
Authors: Sun Ying , Tan Dun Y. , Baskin Carol C. , Baskin Jerry M.
Published: August 2012

Seeds of Alyssum minus, an annual ephemeral in shrublands of north-west China, can produce a large amount of mucilage. The primary aim of this study was to explore the role of mucilage in seed dispersal, settlement onto the soil surface and germination of this species. Width of imbibed seeds with mucilage was three times greater than that of seeds without mucilage, and mass of mucilage increased 167 times after imbibition. Expanded dry mucilage significantly increased wind dispersal of seeds. Floating time on water was greatest for seeds without mucilage, and adherence of soil particles to seeds was greater for seeds with mucilage than for those without mucilage. Mucilage increased rate of water uptake and decreased rate of water loss, and it significantly decreased germination of 0- and 4-week-old seeds. Gibberellic acid promoted germination of 0- and 4-week-old seeds with and without mucilage, but its effect depended on seed age and incubation temperature. Seeds with mucilage subjected to water stress during imbibition and/or incubation germinated faster than those without mucilage. Presence of mucilage on seeds during imbibition significantly increased germination percentages under increased water stress, a first report of this phenomenon. The study has shown that the mucilage of A. minus plays an important role in seed dispersal, seed adhesion to soil (thereby minimising removal by water and predators), seed hydration via increasing surface contact with the substrate, and can serve as a water reservoir for germination, especially under moisture stress.
Ploidy stability of somatic embryo-derived plants in two ecological keystone sedge species (Lepidosperma laterale and L. concavum, Cyperaceae)
Authors: Kodym Andrea , Temsch Eva M. , Bunn Eric , Delpratt John
Published: August 2012

We report on the development of a somatic embryogenesis system for Lepidosperma concavum R.Br. and L. laterale R.Br. and the determination of ploidy stability of plants derived from somatic embryos. These keystone Lepidosperma species cannot currently be returned to restoration sites because of propagation difficulties (i.e. seed dormancy, low seed fill and recalcitrance to vegetative propagation). Three explant types (in vitro-germinated seedlings, immature seed and immature inflorescences) were used for the assessment of callus production potential. Embryogenic callus was induced and multiplied on 1/2MS medium with 2,4-D either alone, or in combination with zeatin. Over 90% of seedling explants of L. laterale produced regenerative calli after 6 weeks and 53% of seedling explants of L. concavum produced calli after 16 weeks on media containing 2,4-D and zeatin. Inflorescence material appeared to be least responsive. High rates of conversion to plants were achieved on medium containing activated charcoal, followed by thidiazuron medium. Acclimatisation success of plants ranged from 86% to 95%. Acclimatised plants grew vigorously under standard nursery conditions. The DNA ploidy level of 486 somatic embryogenesis-derived plantlets was analysed by flow cytometry. Only one plant (=0.2% of all plantlets tested) was found mixoploid. All other plants showed a stable ploidy level and stable C-values within the species. There was a small but significant C-value difference between the two Lepidosperma species. Five variegated plants (=0.3%) were observed among a total of ~1600 plants acclimatised. The application of tissue culture techniques such as somatic embryogenesis brings large-scale production of Lepidosperma plants for revegetation and horticultural purposes closer to commercial feasibility.
Cryptic genetic variability in Swainsona sericea (A. Lee) H. Eichler (Fabaceae): lessons for restoration
Authors: Broadhurst Linda M. , Murray Brian G. , Forrester Robert , Young Andrew G.
Published: August 2012

Grassland communities worldwide have been extensively modified or lost following broadscale agricultural expansion. In south-eastern Australia few natural grasslands remain, with most now being small, isolated and degraded. Conservation and restoration of grassland communities requires an understanding of the impacts of fragmentation on genetic and demographic processes. Swainsona sericea is a perennial grassland herb with conservation listing in New South Wales, Victoria and South Australia. Reproductive output, progeny fitness and genetic diversity were assessed in nine S. sericea populations occupying fragmented grasslands across the southern tablelands of New South Wales. Unexpectedly, four chromosome classes were observed among the populations (2n = 4x = 32, 2n = 10x = 80, 2n = 14x = 112, 2n = 16x = 128), suggesting a more complex taxonomy than is currently recognised. There was no association between reproductive output and population size or ploidy level whereas population size influenced the number of alleles and percentage of polymorphic loci while ploidy influenced effective alleles and expected heterozygosity. Restricted maximum likelihood analyses of progeny growth indicated that ploidy had a significant influence on height, shoot weight, shoot to root ratio and days to germination. The cytological complexity in S. sericea requires clarification, including delineating the cytological boundaries to enable land managers to include this in their conservation and management plans.
Biogeographic origins and reproductive mode of naturalised populations of Acacia saligna
Authors: Millar M. A. , Byrne M.
Published: August 2012

Acacia saligna (Labill.) H.L.Wendl. is a species complex with an extensive history of anthropogenic utilisation and distribution. The taxon is naturalised and invasive in many countries. Extensive morphological variation makes accurate taxonomic identification of populations difficult. We used population genetic analysis to determine the biogeographic origins of 12 naturalised populations sampled from throughout south-eastern South Australia and assess the mode of reproduction (seedling or root suckering) at sites with active recruitment. Ten naturalised populations were assigned to Eastern ‘saligna’, although some also showed a lesser degree of affinity with other entities. A single population was assigned to Western ‘saligna’, but showed some affinity with Eastern ‘saligna’, and one population assigned to subsp. ‘lindleyi’ showed some affinity with Northern ‘lindleyi’. These assignments suggest that although several genetic entities of A. saligna are represented in South Australia, the majority of germplasm has originated from native populations of Eastern ‘saligna’ located around Esperance on Western Australia’s southern coast. Genetic diversity is limited in naturalised A. saligna compared with that present in the native range, suggesting a restricted number of historical introductions. Reproduction is predominantly by seedling recruitment, as opposed to clonal reproduction.
Influence of Ammophila arenaria on half a century of vegetation change in eastern Tasmanian sand dune systems
Authors: Hayes Monica , Kirkpatrick Jamie B.
Published: August 2012

There is strong observational evidence that marram grass Ammophila arenaria transforms vegetation when it invades temperate coastal sand dunes. Because of contemporaneous marram grass introduction, sea level rise, climate change and coastal land use change, we use control dune systems to test the hypotheses that marram grass displaces native sand-binding grasses, reduces the area of bare sand and facilitates shrub invasion. We mapped vegetation from aerial photographs at four times between 1948 and 2007 on four pairs of sand dune systems, with one of each pair being heavily invaded by marram grass during the period of observation. We calculated the transitions between cover types between times. On the dune systems with marram grass, dunes became taller and more regular, native sand-binders became rare, bare sand decreased in area and native shrubs colonised the stabilised dunes. In the absence of marram grass the dunes remained dynamic, with much bare sand. At two of these control sites, increases in wind strength and sea level may have facilitated the development of transgressive dunes and eroded the native sand-binders. At the remaining two control sites, native sand-binders created low incipient foredunes. Shrub invasion occurred at most control sites. We conclude that marram grass does displace native sand-binders and decrease the proportion of bare sand, but that shrub invasion is partly independent of its introduction.
High temperature tolerance in chickpea and its implications for plant improvement
Authors: Devasirvatham V. , Tan D. K. Y. , Gaur P. M. , Raju T. N. , Trethowan R. M.
Published: August 2012

Chickpea (Cicer arietinum L.) is an important food legume and heat stress affects chickpea ontogeny over a range of environments. Generally, chickpea adapts to high temperatures through an escape mechanism. However, heat stress during reproductive development can cause significant yield loss. The most important effects on the reproductive phase that affect pod set, seed set and yield are: (1) flowering time, (2) asynchrony of male and female floral organ development, and (3) impairment of male and female floral organs. While this review emphasises the importance of high temperatures >30°C, the temperature range of 32–35°C during flowering also produces distinct effects on grain yield. Recent field screening at ICRISAT have identified several heat-tolerant germplasm, which can be used in breeding programs for improving heat tolerance in chickpea. Research on the impact of heat stress in chickpea is not extensive. This review describes the status of chickpea production, the effects of high temperature on chickpea, and the opportunities for genetic improvement of chickpea tolerance to high temperatures.