bluuebunny/crossref_metadata_2025 huggingface dataset:
Context Effects on Test Performance
Authors: Khorramdel Lale , Frebort Martina
Published: May 2011

The effects of varied test order within a computer test battery on test performance were investigated. An experiment was performed to determine whether completing objective personality tests sensu R. B. Cattell affects test performance in subsequent cognitive ability tests and vice versa. The sample consisted of managers of an industrial corporation (an automotive supplier) in “higher management positions” (business managers, department chiefs, and team leaders) who attended an investigation of their professional potential that resembled a real selection situation. It was hypothesized that carry-over and priming effects, as well as fatigue and learning effects might occur. Results of a MANOVA showed a main effect of test order on objective personality tests, since “frustration tolerance” decreased and “decisiveness” increased when objective personality tests were presented subsequent to cognitive ability tests, while cognitive ability tests were not affected by prior objective personality tests.
Biominerals and the vertical flux of particulate organic carbon from the surface ocean
Authors: Balch W. M. , Bowler B. C. , Drapeau D. T. , Poulton A. J. , Holligan P. M.
Published: May 2011

Particulate inorganic carbon (PIC; calcium carbonate) is thought to be a significant source of light scattering in the sea. It also provides ballast for particulate matter, driving the ocean's biological carbon pump. During three trans‐Atlantic cruises, we measured particle optical properties plus concentrations of the three major components of sinking aggregates [particulate organic carbon (POC), PIC and biogenic silica (BSi)]. PIC contributed 15–23% of particle backscattering in oligotrophic subtropical gyres and temperate waters. Light scattering properties allowed quantification of the surface PIC:POC ratio. The ratio of the two ballast minerals (PIC:BSi) was significantly, inversely, correlated to POC concentration, allowing robust modeling of the density of sinking aggregates. Results showed greater PIC:POC ratios and sinking rates in oligotrophic regions due to greater relative abundance of PIC.
Creativity and Discovery as Blind Variation: Campbell's (1960) BVSR Model after the Half-Century Mark
Authors: Simonton Dean Keith
Published: May 2011

This article assesses and extends Campbell's (1960) classic theory that creativity and discovery depend on blind variation and selective retention (BVSR), with special attention given to blind variations (BVs). The treatment begins by defining creativity and discovery, variant blindness versus sightedness, variant utility and selection, and ideational variants versus creative products. These definitions lead to BV identification criteria: (a) intended BV, which entails both systematic and stochastic combinatorial procedures; and (b) implied BV, which involves both variations with properties of blindness (variation superfluity and backtracking) and processes that should yield variant blindness (associative richness, defocused attention, behavioral tinkering, and heuristic search). These conceptual definitions and identification criteria then have implications for four persistent issues, namely, domain expertise, ideational randomness, analogical equivalence, and personal volition. Once BV is suitably conceptualized, Campbell's theory continues to provide a fruitful approach to the understanding of both creativity and discovery.
Spatiotemporal Characteristics of Postischemic Hyperperfusion with Respect to Changes in T1, T2, Diffusion, Angiography, and Blood–Brain Barrier Permeability
Authors: Shen Qiang , Du Fang , Huang Shiliang , Duong Timothy Q
Published: May 2011

The spatiotemporal dynamics of postischemic hyperperfusion (HP) remains incompletely understood. Diffusion, perfusion, T2, T1, angiographic, dynamic susceptibility-contrast magnetic resonance imaging (MRI) and magnetic resonance angiography were acquired longitudinally at multiple time points up to 7 days after stroke in rats subjected to 30-, 60-, and 90-minutes middle cerebral artery occlusion (MCaO). The spatiotemporal dynamics of postischemic HP was analyzed and compared with T1, T2 and blood-brain barrier (BBB) changes. No early HP within 3 hours after recanalization was observed. Late (≥12 hours) HP was present in all animals of the 30-minute MCAO group (N=20), half of the animals in the 60-minute MCAO group ( N=8), and absent in the 90-minute MCAO group (N=9). Dynamic susceptibility-contrast MRI and magnetic resonance angiography corroborated HP. Hyperperfusion preceded T2 increase in some animals, but HP and T2 changes temporally coincided in others. T2 peaked first at 24 hours whereas HP peaked at 48 hours after occlusion, and HP resolved by day 7 in most animals at which point the arteries became tortuous. Pixel-by-pixel tracking analysis showed that tissue did not infarct (migrated from core or mismatch at 30 minutes to normal at 48 hours) showed normal cerebral blood flow (CBF), whereas infarct tissue (migrated from core or mismatch at 30 minutes to infarct at 48 hours) showed exaggerated CBF, indicating that HP was associated with poor outcome.
Cerebral autoregulation in Alzheimer's disease
Authors: Claassen Jurgen AHR , Zhang Rong
Published: May 2011

Cerebral autoregulation aims to stabilize blood flow to the brain during variations in perfusion pressure, thus protecting the brain against the risks of low or high systemic blood pressure. This vital mechanism is severely impaired in the transgenic mouse model of Alzheimer's disease (AD) that abundantly produces amyloid-β peptide β1-42. These observations have been extrapolated to human AD, wherein impairment of autoregulation could have important implications for the clinical management and prevention of AD. Research on cerebral autoregulation in human AD, however, has only recently become available. Contrary to the animal models, preliminary studies suggest that cerebral autoregulation is preserved in patients with AD. Further research is urgently needed to elucidate this discrepancy in the current literature, given the accumulating evidence that implicates cerebrovascular pathology in AD.
The Importance of Production Frequency in Therapy for Childhood Apraxia of Speech
Authors: Edeal Denice Michelle , Gildersleeve-Neumann Christina Elke
Published: May 2011

Purpose

This study explores the importance of production frequency during speech therapy to determine whether more practice of speech targets leads to increased performance within a treatment session, as well as to motor learning, in the form of generalization to untrained words.

Method

Two children with childhood apraxia of speech were treated with an alternating treatment AB design, with production frequency differing in the 2 treatments. The higher production frequency treatment required 100+ productions in 15 min, while the moderate-frequency treatment required 30–40 productions in the same time period. One child was treated 3 times weekly for 11 weeks; the other child was treated twice weekly for 5 weeks. At the conclusion of each treatment phase, 5 min of probes were administered to determine whether generalization had occurred. Maintenance data to measure performance and learning were collected after a break from treatment.

Results

Both children showed improvement on all targets; however, the targets with the higher production frequency treatment were acquired faster, evidenced by better in-session performance and greater generalization to untrained probes.

Conclusions

Both treatment designs were effective, though frequent and intense practice of speech resulted in more rapid response to treatment in 2 children whose primary communication difficulty was childhood apraxia of speech.
Effect of Verb Network Strengthening Treatment in Moderate-to-Severe Aphasia
Authors: Edmonds Lisa A. , Babb Michelle
Published: May 2011

Purpose

This Phase II treatment study examined the effect of Verb Network Strengthening Treatment (VNeST) on individuals with moderate-to-severe aphasia. Research questions addressed (a) pre- to posttreatment changes and pretreatment to treatment phase changes on probe sentences containing trained verbs (e.g., “The carpenter is
measuring
the stairs”) and semantically related untrained verbs (e.g., “The nurse is
weighing
the baby”); (b) lexical retrieval changes in single-word naming, sentence, and discourse measures; (c) functional communication by way of proxy and participant report; and (d) error evolution.

Method

A multiple-baseline approach across participants was used. Effect sizes were calculated for pre- and posttreatment and maintenance probe responses. A
C
statistic was used to determine changes from the baseline to treatment phases.

Results

One participant exhibited improvement on all generalization measures, whereas the other participant exhibited more limited generalization. Both participants showed improvement on the functional communication measure.

Conclusions

As predicted, the participants did not show the same extent of improvement that was observed in participants with more moderate aphasia (Edmonds, Nadeu, & Kiran, 2009). Nonetheless, the findings suggest that VNeST may be appropriate for persons with moderate-to-severe aphasia, especially with a small adaptation to the treatment protocol that will be retained for future iterations of VNeST.
What Factors Place Children With Speech Sound Disorders at Risk for Reading Problems?
Authors: Anthony Jason L. , Aghara Rachel Greenblatt , Dunkelberger Martha J. , Anthony Teresa I. , Williams Jeffrey M. , Zhang Zhou
Published: May 2011

Purpose

To identify weaknesses in print awareness and phonological processing that place children with speech sound disorders (SSDs) at increased risk for reading difficulties.

Method

Language, literacy, and phonological skills of 3 groups of preschool-age children were compared: a group of 68 children with SSDs, a group of 68 peers with normal speech matched on receptive vocabulary, and a group of 68 peers with normal speech and language.

Results

The SSD group demonstrated impairments in expressive phonological awareness (
t
s = 3.45 to 8.17,
p
s < .001, effect size [ES] = 0.51 to 1.04), receptive phonological awareness (
z
s = 2.26 to 5.21,
p
s ≤ .02, ES = 0.39 to 0.79), accessing phonological representations (
z
s = 3.34 to 5.83,
p
s < .001, ES = 0.59 to 0.91), quality of phonological representations (
z
s = 2.35 to 13.11,
p
s ≤ .02, ES = 0.44 to 1.56), and word reading (
t
s = 2.48 to 4.42,
p
s ≤ .01, ES = 0.22 to 0.54). Analyses of covariance found that lower performances of the SSD group on tests of phonological awareness and word reading could be explained by their weaknesses in quality and accessibility of phonological representations.

Conclusions

The present study makes a significant theoretical contribution to the literature as the first study, to our knowledge, that has tested the hypothesis that weaknesses in representation-related phonological processing may underlie the difficulties in phonological awareness and reading that are demonstrated by children with SSDs.
Pharyngeal Pressure Generation During Tongue-Hold Swallows Across Age Groups
Authors: Doeltgen Sebastian H. , Macrae Phoebe , Huckabee Maggie-Lee
Published: May 2011

Purpose

To compare the effects of the tongue-hold swallowing maneuver on pharyngeal pressure generation in healthy young and elderly research volunteers.

Method

Sixty-eight healthy research volunteers (young,
n
= 34, mean age = 26.8 years,
SD
= 5.5; elderly,
n
= 34, mean age = 72.6 years,
SD
= 4.8; sex equally represented) performed 5 noneffortful saliva swallows and 5 tongue-hold swallows each. Amplitude and duration of pharyngeal pressure were investigated during both swallowing conditions with solid-state pharyngeal manometry at the level of the oropharynx, hypopharynx, and upper esophageal sphincter (UES).

Results

At both pharyngeal levels, tongue-hold swallows produced lower peak pressure compared with saliva swallows. During tongue-hold swallows, UES relaxation pressure was increased in the elders, whereas the younger group displayed a trend toward reduced relaxation pressure. Elderly individuals produced pressure longer during control swallows in the oropharynx and hypopharynx than young individuals.

Conclusions

The tongue-hold maneuver affects oropharyngeal and hypopharyngeal pressure in the young and elders in similar ways, whereas effects on UES peak relaxation pressure differ between age groups. Reduced pharyngeal peak pressure and increased UES relaxation pressure underscore the notion that tongue-hold swallows should not be performed when bolus is present. Long-term training effects remain to be investigated.
Exponential synchronization of chaotic systems with time-varying delays and parameter mismatches via intermittent control
Authors: Cai Shuiming , Hao Junjun , Liu Zengrong
Published: May 2011

This paper studies the synchronization of coupled chaotic systems with time-varying delays in the presence of parameter mismatches by means of periodically intermittent control. Some novel and useful quasisynchronization criteria are obtained by using the methods which are different from the techniques employed in the existing works, and the derived results are less conservative. Especially, a strong constraint on the control width that the control width should be larger than the time delay imposed by the current references is released in this paper. Moreover, our results show that the synchronization criteria depend on the ratio of control width to control period, but not the control width or the control period. Finally, some numerical simulations are given to show the effectiveness of the theoretical results.
Simulations of stable compact proton beam acceleration from a two-ion-species ultrathin foil
Authors: Yu T. P. , Pukhov A. , Shvets G. , Chen M. , Ratliff T. H. , Yi S. A. , Khudik V.
Published: May 2011

We report stable laser-driven proton beam acceleration from ultrathin foils consisting of two ion species: heavier carbon ions and lighter protons. Multidimensional particle-in-cell simulations show that the radiation pressure leads to very fast and complete spatial separation of the species. The laser pulse does not penetrate the carbon ion layer, avoiding the proton Rayleigh–Taylor (RT)-like instability. Ultimately, the carbon ions are heated and spread extensively in space. In contrast, protons always ride on the front of the carbon ion cloud, forming a compact high quality bunch. We introduce a simple three-interface model to interpret the instability suppression in the proton layer. The model is backed by simulations of various compound foils such as carbon–deuterium and carbon–tritium foils. The effects of the carbon ions’ charge state on proton acceleration are also investigated. It is shown that with the decrease of the carbon ion charge state, both the RT-like instability and the Coulomb explosion degrade the energy spectrum of the protons. Finally, full 3D simulations are performed to demonstrate the robustness of the stable two-ion-species regime.
Linear gyrokinetic theory and computation of the gyrocenter motion based on the exact canonical variables for axisymmetric tokamaks
Authors: Xu Yingfeng , Xiao Xiaotao , Wang Shaojie
Published: May 2011

Linear gyrokinetic theory based on the Lie-transform perturbation method is presented in terms of the exact canonical variables. In the linear drift approximation, it is shown that the gyrocenter equations of motion based on the canonical variables are equivalent to the usual guiding-center equations of motion. A numerical code is developed to advance the gyrocenter motion in terms of the exact canonical variables with arbitrary perturbations. It is found that a static magnetic island in a tokamak has little effect on the trapped particle orbits due to the conservation of the longitudinal invariant; and it induces the island structure of passing particle orbits due to the fact that the longitudinal invariant for the passing particles is broken by the asymmetric perturbation.
Gyrokinetic simulation of momentum transport with residual stress from diamagnetic level velocity shears
Authors: Waltz R. E. , Staebler G. M. , Solomon W. M.
Published: May 2011

Residual stress refers to the remaining toroidal angular momentum (TAM) flux (divided by major radius) when the shear in the equilibrium fluid toroidal velocity (and the velocity itself) vanishes. Previously [Waltz et al., Phys. Plasmas 14, 122507 (2007); errata 16, 079902 (2009)], we demonstrated with GYRO [Candy and Waltz, J. Comp. Phys. 186, 545 (2003)] gyrokinetic simulations that TAM pinching from (ion pressure gradient supported or diamagnetic level) equilibrium E×B velocity shear could provide some of the residual stress needed to support spontaneous toroidal rotation against normal diffusive loss. Here we show that diamagnetic level shear in the intrinsic drift wave velocities (or “profile shear” in the ion and electron density and temperature gradients) provides a comparable residual stress. The individual signed contributions of these small (rho-star level) E×B and profile velocity shear rates to the turbulence level and (rho-star squared) ion energy transport stabilization are additive if the rates are of the same sign. However because of the additive stabilization effect, the contributions to the small (rho-star cubed) residual stress is not always simply additive. If the rates differ in sign, the residual stress from one can buck out that from the other (and in some cases reduce the stabilization.) The residual stress from these diamagnetic velocity shear rates is quantified by the ratio of TAM flow to ion energy (power) flow (M/P) in a global GYRO core simulation of a “null” toroidal rotation DIII-D [Mahdavi and Luxon, Fusion Sci. Technol. 48, 2 (2005)] discharge by matching M/P profiles within experimental uncertainty. Comparison of global GYRO (ion and electron energy as well as particle) transport flow balance simulations of TAM transport flow in a high-rotation DIII-D L–mode quantifies and isolates the E×B shear and parallel velocity (Coriolis force) pinching components from the larger “diffusive” parallel velocity shear driven component and the much smaller profile shear residual stress component.
Global limits on kinetic Alfvénon speed in quasineutral plasmas
Authors: Akbari-Moghanjoughi M.
Published: May 2011

Large-amplitude kinetic Alfvénon (exact Alfvén soliton) matching condition is investigated in quasineutral electron-ion and electron-positron-ion plasmas immersed in a uniform magnetic field. Using the standard pseudopotential method, the magnetohydrodynamics equations are exactly solved, and a global allowed matching condition for propagation of kinetic solitary waves is derived. It is remarked that, depending on the plasma parameters, the kinetic solitons can be sub-Alfvénic or super-Alfvénic, in general. It is further revealed that, either upper or lower soliton speed-limit is independent of fractional plasma parameters. Furthermore, the soliton propagation angle with respect to that of the uniform magnetic field is found to play a fundamental role in controlling the soliton matching speed-range.
Electron inertia effects on the planar plasma sheath problem
Authors: Duarte V. N. , Clemente R. A.
Published: May 2011

The steady one-dimensional planar plasma sheath problem, originally considered by Tonks and Langmuir, is revisited. Assuming continuously generated free-falling ions and isothermal electrons and taking into account electron inertia, it is possible to describe the problem in terms of three coupled integro-differential equations that can be numerically integrated. The inclusion of electron inertia in the model allows us to obtain the value of the plasma floating potential as resulting from an electron density discontinuity at the walls, where the electrons attain sound velocity and the electric potential is continuous. Results from numerical computation are presented in terms of plots for densities, electric potential, and particles velocities. Comparison with results from literature, corresponding to electron Maxwell–Boltzmann distribution (neglecting electron inertia), is also shown.
Diffraction-controlled backscattering threshold and application to Raman gap
Authors: Rose Harvey A. , Mounaix Philippe
Published: May 2011

In most classic analytical models of linear stimulated scatter, light diffraction is omitted, a priori. However, modern laser optic typically includes a variant of the random phase plate [Y. Kato et al., Phys. Rev. Lett. 53, 1057 (1984)], resulting in diffraction limited laser intensity fluctuations—or localized speckles—which may result in explosive reflectivity growth as the average laser intensity approaches a critical value [H. A. Rose and D. F. DuBois, Phys. Rev. Lett. 72, 2883 (1994)]. Among the differences between stimulated Raman scatter (SRS) and stimulated Brillouin scatter is that the SRS scattered light diffracts more strongly than the laser light with increase of electron density. This weakens the tendency of the SRS light to closely follow the most amplified paths, diminishing gain. Let G0 be the one-dimensional power gain exponent of the stimulated scatter. In this paper we show that differential diffraction gives rise to an increase of G0 at the SRS physical threshold with increase of electron density up to a drastic disruption of SRS as electron density approaches one fourth of its critical value from below. For three wave interaction lengths not small compared to a speckle length, this is a physically robust Raman gap mechanism.
Desynchronization bifurcation of coupled nonlinear dynamical systems
Authors: Acharyya Suman , Amritkar R. E.
Published: May 2011

We analyze the desynchronization bifurcation in the coupled Rössler oscillators. After the bifurcation the coupled oscillators move away from each other with a square root dependence on the parameter. We define system transverse Lyapunov exponents (STLE), and in the desynchronized state one is positive while the other is negative. We give a simple model of coupled integrable systems with quadratic nonlinearity that shows a similar phenomenon. We conclude that desynchronization is a pitchfork bifurcation of the transverse manifold. Cubic nonlinearity also shows the bifurcation, but in this case the STLEs are both negative.
Role of fluctuations and flows in sustaining mean profiles in a current less toroidal plasma
Authors: Goud T. S. , Ganesh R. , Saxena Y. C. , Raju D. , Sathyanarayana K. , Mohandas K. K. , Chavda C.
Published: May 2011

The flow and fluctuation measurements in a simple magnetized current less toroidal plasma have been conducted. The measured plasma parameter profiles are observed to be accompanied by large fluctuations. The existence of large fluctuations and filling of plasma in the entire radial domain are observed to be closely related to each other. The E×B drift velocities calculated from the gradient of measured mean plasma potential profile have shown significant deviation from the net flow velocity measurements. Interestingly, it is observed that the measured fluctuation driven flow velocity, which is opposite in direction to the mean field driven flow, partially accounts for the observed difference between the net flow and the mean electric field driven flow.
Polar molecules in the quantum regime
Authors: Jin Deborah S. , Ye Jun
Published: May 2011

With molecular gases so cold that collisions must be described quantum mechanically, researchers are studying chemical reactions as they’ve never been seen before.
The neutrino’s elusive helicity reversal
Authors: Goldhaber Alfred Scharff , Goldhaber Maurice
Published: May 2011

Neutrinos have tiny but nonzero masses. So their helicities can, in principle, be reversed. Detecting that reversal by chasing a neutrino seems impossible in the foreseeable future. But if neutrinos are their own antiparticles, indirect detection may be possible.
Compound-specific bromine isotope compositions of one natural and six industrially synthesised organobromine substances
Authors: Carrizo Daniel , Unger Maria , Holmstrand Henry , Andersson Per , Gustafsson Örjan , Sylva Sean P. , Reddy Christopher M.
Published: May 2011

Environmental contextBrominated organic compounds of both natural and anthropogenic origin are commonly found in the environment. Bromine has two stable isotopes and the isotopic composition of brominated compounds may vary depending on production pathways and degradation processes. These variations are a result of isotope fractionation effects, when heavy isotopes react slower than lighter isotopes. We apply compound-specific bromine isotope analysis to industrial brominated organic compounds, and one naturally produced analogue, to test the feasibility of the technique to investigate the source and environmental fate of these compounds.
AbstractThe stable bromine isotopic composition (δ81Br) was determined for six industrially synthesised brominated organic compounds (BOCs) and one natural BOC by gas-chromatography multi-collector inductively coupled plasma mass spectrometry (GC-mcICP-MS). The δ81Br compositions of brominated benzenes, phenols (both natural and industrial), anisoles, and naphthalenes were constrained with the standard differential measurement approach using as reference a monobromobenzene sample with an independently determined δ81Br value (–0.39‰ v. Standard Mean Ocean Bromide, SMOB). The δ81Br values for the industrial BOCs ranged from –4.3 to –0.4‰. The average δ81Br value for the natural compound (2,4-dibromophenol) was 0.2 ± 1.6‰ (1 s.d.), and for the identical industrial compound (2,4-dibromophenol) –1.1 ± 0.9‰ (1 s.d.), with a statistically significant difference of ~1.4 (P < 0.05). The δ81Br of four out of six industrial compounds was found to be significantly different from that of the natural sample. These novel results establish the bromine isotopic variability among the industrially produced BOCs in relation to a natural sample.
Quantification of secondary organic aerosol in an Australian urban location
Authors: Keywood Melita , Guyes Helen , Selleck Paul , Gillett Rob
Published: May 2011

Environmental contextParticulate matter is detrimental to human health necessitating air quality standards to ensure that populations are not exposed to harmful levels of air pollutants. We quantified, for the first time in an Australian city, secondary organic aerosol produced in the atmosphere by chemical reactions, and show that it constitutes a significant fraction of the fine particulate matter. Secondary organic aerosol should be considered in regulations to control particulate matter and ozone.
AbstractThe contribution of secondary organic aerosol (SOA) to particulate mass (PM) in an Australian urban airshed is quantified for the first time in this work. SOA is estimated indirectly using the elemental carbon tracer method. The contribution of primary organic carbon (OC) to PM is determined using ambient air quality data, which is used to indicate photochemical activity and as a tracer for a general vehicular combustion source. In addition, levoglucosan concentrations were used to determine the contribution of wood heater emissions to primary OC. The contribution of bushfire smoke to primary OC emissions was determined from the organic and elemental carbon (OC/EC) ratios measured in bushfire source samples. The median annual SOA concentration determined in this work was 1.1 µg m–3, representing ~13% of PM2.5 median concentrations on an annual basis (assuming a ratio of organic mass (OM) to OC of 1.6). Significantly higher SOA concentrations were determined when bushfire smoke affected the airshed; however, the SOA fraction of PM2.5 was greatest during the autumn and early winter months when the formation of inversions allows build up of particles produced by domestic wood-heater emissions.
Dissolution and solubility of the arsenate - phosphate hydroxylapatite solid solution [Ca5(PxAs1 - xO4)3(OH)] at 25°C
Authors: Zhang Xuehong , Zhu Yinian , Zeng Honghu , Wang Dunqiu , Liu Jie , Liu Huili , Qian Meifang , Xu Liwei
Published: May 2011

Environmental contextApatites form a large family of minerals and compounds that can incorporate a variety of ions, including arsenate that can substitute for phosphate. Apatites may therefore control the concentration of arsenic in some aqueous environments. This manuscript describes the synthesis and characterisation of the arsenate–phosphate hydroxylapatite solid solution and the solid solution–aqueous solution interaction. Abstract Nine different members of the arsenate–phosphate hydroxylapatite solid solution [Ca5(PxAs1–xO4)3(OH)] were prepared and characterised by various techniques, and then dissolution of the synthetic solids was studied at 25°C and pH 2 in a series of batch experiments. The concentrations of aqueous arsenate species increased rapidly at the beginning of the dissolution and reached a steady-state after 480 h. The concentrations of aqueous phosphate species increased very fast initially and reached a peak value within the first hour of dissolution and then declined slowly with time and remained constant after 240–360 h. The solubility of the Ca5(PxAs1–xO4)3(OH) solid solution increased and its stability decreased with an increase in the mole fraction of Ca5(AsO4)3(OH). The dissolution followed or slightly overshot the Lippmann solutus curve, then approached the solutus curve. The Ca5(AsO4)3(OH)-poor solid solution was in equilibrium with the arsenate-rich aqueous solution.
CO emissions from biomass burning in South-east Asia in the 2006 El Niño year: shipboard and AIRS satellite observations
Authors: Nara Hideki , Tanimoto Hiroshi , Nojiri Yukihiro , Mukai Hitoshi , Zeng Jiye , Tohjima Yasunori , Machida Toshinobu
Published: May 2011

Environmental contextAtmospheric carbon monoxide greatly affects the abundance of environmentally important gases, including methane, hydrochlorofluorocarbons and tropospheric ozone. We present evidence for episodes of CO pollution over the tropical Pacific Ocean resulting from intensive biomass burning in South-east Asia and Northern Australia during the 2006 El Niño year. We discuss the locations of the CO emissions and their long-range transport.
AbstractBiomass burning is often associated with climate oscillations. For example, biomass burning in South-east Asia is strongly linked to El Niño–southern oscillation activity. During October and November of the 2006 El Niño year, a substantial increase in CO mixing ratios was detected over the Western tropical Pacific Ocean by shipboard observations routinely operated between Japan and Australia and New Zealand. Combining in-situ measurements, satellite observations, and an air trajectory model simulation, two high CO episodes were identified originating from biomass burning in Borneo, Sumatra, New Guinea, and Northern Australia. Between 15°N and the Equator, marked CO enhancements were encountered associated with a significant correlation between CO and CO2 and between CO and O3. The ΔCO/ΔCO2 ratio observed in the fire plume was considerably high (171 ppbv ppmv–1), suggesting substantial contributions from peat soil burning in Indonesia. In contrast, the ΔO3/ΔCO ratio was only 0.05 ppbv ppbv–1, indicating that net photochemical production of O3 in the plume was negligible during long-range transport in the lower troposphere over the Western tropical North Pacific.
Composition and molar mass characterisation of bacterial extracellular polymeric substances by using chemical, spectroscopic and fractionation techniques
Authors: Alasonati Enrica , Slaveykova Vera I.
Published: May 2011

Environmental contextExtracellular polymeric substances (EPS) released by microorganisms are an important component of organic matter in the environment. EPS play an essential role in cell adhesion to surfaces, biofilm and floc formation, soil aggregation and stability and in the activated sludge of waste water treatment plants. EPS are complex mixtures containing components of different chemical nature and molecular size, which make their characterisation difficult. The present work explores the link between chemical composition and molar-mass distribution of the EPS released by the bacterium Sinorhizobium meliloti by using a combination of chemical, spectroscopic and fractionation techniques. AbstractThe chemical composition and molar-mass distribution of extracellular polymeric substances (EPS) produced by the bacterium Sinorhizobium meliloti have been characterised by combining asymmetrical flow field-flow fractionation (AFlFFF), chemical and spectroscopic techniques. The relationship between the EPS composition and molar-mass distribution has been studied by comparing the characteristics of EPS excreted by the wild type S. meliloti and by a mutant deficient in the production of high-molar-mass EPS, as well as by the analysis of total protein content in the collected AFlFFF fractions. Total organic carbon, protein and polysaccharide contents of the EPS were also determined. Obtained results demonstrate the existence of two major populations with weight-average molar masses of 1.40 × 105 and 4.57 × 105 g mol–1 respectively. The lower molar-mass population contained predominantly protein-like substances, detectable by UV-VIS spectroscopy, whereas the higher molar-mass population was rich in exopolysaccharides and exoproteins. These findings are in general agreement with the size distributions and chemical heterogeneity observed by nanoparticle tracking analysis, and the characterisation of the composition of all the EPS by different analytical techniques.
FeII oxidation by molecular O2 during HCl extraction
Authors: Porsch Katharina , Kappler Andreas
Published: May 2011

Environmental contextIn the environment, iron exists mainly as FeII and FeIII and plays an important role in biogeochemical processes. The FeII and FeIII content is often quantified by hydrochloric acid extraction and the acid is thought to prevent FeII oxidation by oxygen. However, we found that with increasing HCl concentration and temperature, oxidation of FeII by oxygen is accelerated. Therefore, in order to obtain reliable results extractions should be performed with dilute HCl or in the absence of oxygen. AbstractHCl is commonly used to stabilise FeII under oxic conditions and is often included in Fe extractions. Although FeII oxidation by molecular O2 in HCl is described in the field of hydrometallurgy, this phenomenon has not been systematically studied in environmentally relevant systems. The extent of FeII oxidation by O2 during extraction of soils and magnetite by HCl and in HCl/FeCl2 solutions was therefore quantified. FeII was stable in 1 M HCl at room temperature for several days, whereas in 6 M HCl at 70°C, 90% of the FeII was oxidised within 24 h. In the absence of O2, no FeII oxidation occurred. Experiments at low pH with increasing H+ or Cl– concentration alone and geochemical modelling suggested that the formation of complexes of FeII and HCl may be responsible for the observed FeII oxidation. The use of strictly anoxic conditions for Fe extraction by HCl to obtain reliable Fe redox speciation data is therefore recommended.
A kinetic investigation of unimolecular reactions involving trace metals at post-combustion flue gas conditions
Authors: Wilcox Jennifer
Published: May 2011

Environmental contextUnderstanding trace metal speciation in coal combustion flue gases is imperative to the design of effective capture technologies to prevent their release into the atmosphere. Unfortunately much of the kinetics that dictate trace metal speciation are not known and the current study focuses for the first time on the kinetics for three reactions involving mercury and one involving selenium. Rate constant expressions are provided over a broad temperature range (i.e. 298–2000 K), indicative of post-combustion flue gas conditions. AbstractAb-initio methods were carried out to calculate forward and reverse rate constant data for the following reactions: Hg + Cl2 ↔ HgCl2, HgCl + Cl ↔ HgCl2, Hg + O ↔ HgO, and Se + H2 ↔ SeH2. Theoretical predictions of bond distances, vibrational frequencies and enthalpies of reaction are compared to available experimental data to determine the level of theory most appropriate for predicting kinetic parameters. The pseudopotentials ECP60MDF and RECP60VDZ were used for mercury in combination with B3LYP or QCISD(T) methods whereas the complete 6–311++G(3df,3pd) Pople basis set with the CCSD(T) method was used for selenium. Potential energy curves for each reaction were constructed and a variational approach along with RRKM theory was used to predict rate constants from 298 to 2000 K. Reactions HgCl + Cl ↔ HgCl2 and Hg + O ↔ HgO were found to have a strong negative temperature dependence, whereas the insertion reactions Hg + Cl2 ↔ HgCl2 and Se + H2 ↔ SeH2 were found to proceed very slowly with large pre-exponential factors.
Combined effects of contrast between poor and rich patches and overall nitrate concentration on Arabidopsis thaliana root system structure
Authors: Blouin Manuel , Puga-Freitas Ruben
Published: May 2011

The law of correlative inhibition states that roots in a richer environment develop more intensively if other roots of the same plant are in a poorer environment. This probably occurs only when the cost of emitting these roots in the rich patch is compensated by the advantage of having more roots, i.e. in situations where the difference in concentration between rich and poor patches is strong or the overall nutrient amount in the environment is low. For the first time, we tested root system response to combined gradients of contrast between poor and rich patches and of overall NO3– concentration in agar gels. We set up a factorial in vitro experiment crossing contrast (null, weak, strong heterogeneity) with overall NO3– concentration (deficient, optimal, excessive). We observed an increase in ramification density with increasing heterogeneity in deficient situations; but a decrease with increasing heterogeneity in excessive situations. The interaction between overall NO3– concentration and heterogeneity had a significant effect on root ramification density and the distribution of root length in diameter classes. The overall nutrient status of the soil has to be considered to understand the effect of heterogeneity on plant development at the morphological as well as at the molecular level.
Quantifying abortion rates of reproductive organs and effects of contributing factors using time-to-event analysis
Authors: Wubs A. M. , Heuvelink E. , Marcelis L. F. M. , Hemerik L.
Published: May 2011

Time-to-event analysis, or survival analysis, is a method to analyse the timing of events and to quantify the effects of contributing factors. We apply this method to data on the timing of abortion of reproductive organs. This abortion often depends on source and sink strength. We hypothesise that the effect of source and sink strength on abortion rate can be quantified with a statistical model, obtained via survival analysis. Flower and fruit abortion in Capsicum annuum L., observed in temperature and planting density experiments, were analysed. Increasing the source strength as well as decreasing the sink strength decreased the abortion rate. The effect was non-linear, e.g. source strengths above 6 g CH2O per plant per d did not decrease abortion rates further. The maximum abortion rate occurred around 100 degree-days after anthesis. Analyses in which sink strength was replaced with the number of fruits in a specified age category had an equal or better fit to the data. We discuss the advantages and disadvantages of using survival analyses for this kind of data. The technique can also be used for other crops showing reproductive organ abortion (e.g. soybean (Glycine max L.), cucumber (Cucumis sativus L.)), but also on other event types like bud break or germination.
Albert Russell ('Bert') Main 1919 - 2009
Authors: Bradshaw S. D.
Published: May 2011

Bert Main (1919?2009)was recognized both nationally and internationally as one of Australia's leading zoologists and a gifted naturalist. His research and ecological teaching on a wide variety of animals, including frogs, reptiles, birds, insects and marsupials, laid the foundations for three generations of graduate students who were inspired by his imagination and biological insight. His foresight and energy as an administrator on government bodies also led to the creation of some of Western Australia's most important National Parks and Nature Reserves that are vital for the preservation of Australia's rich biodiversity and form part of his enduring legacy.
Relationship between late embryonic mortality and the increase in plasma advanced oxidised protein products (AOPP) in dairy cows
Authors: Celi Pietro , Merlo Mariacristina , Da Dalt Laura , Stefani Annalisa , Barbato Olimpia , Gabai Gianfranco
Published: May 2011

The involvement of protein oxidation in embryonic mortality (EM) has been poorly investigated in cows. Advanced oxidation protein products (AOPP) are markers of protein oxidation generated by activated neutrophils and involved in inflammation. The aim of this work was to study AOPP in cow plasma and their relationship with late EM. The outcomes of 158 artificial inseminations (AI) were examined in 72 cows, which were classified ex post on the basis of blood progesterone and pregnancy-associated glycoprotein concentrations and clinical confirmation of pregnancy into the following categories: (1) positive (AI+, resulted in pregnancy, n = 58), (2) negative (AI–, did not result in pregnancy, n = 86) and (3) embryonic mortality (EM, n = 14). Plasma protein fractions, malondialdehyde (MDA), total glutathione and AOPP were measured at AI (Day 0) and on Days 15, 28, 35, 45 and 60. MDA was significantly higher in EM than AI+ and AI– animals on Day 45, and than AI+ animals on Day 60 (P < 0.05). Mean plasma AOPP concentrations were significantly higher in the EM group (P < 0.01) and the ratio of AOPP : albumin was significantly higher in the EM group on Days 15, 28, 45 and 60 (P < 0.05). Based on the temporal pattern of the AOPP : albumin ratio, we propose that oxidative stress is implicated in and may possibly be a cause of EM.
Una aproximación empírica a la ­clasificación y traducción de las figuras retóricas en la publicidad
Authors: Calzada Perez Maria
Published: May 2011

Since ancient times the suasive value of rhetorical figures has been vastly studied. In fact, Aristotle himself argued that the aim of rhetoric was not just to persuade but to find the best methods of persuasion (Aristotle, Retorica, ed. 1990). These methods have been frequently used in advertising, where they are employed to capture the consumer’s attention and, consequently, to sell the advertised product. However (despite the frequent appearance of rhetorical figures in advertising), there is a scarcity of studies on the role of these persuasive mechanisms in the translation of publicity. Bearing upon the “new rhetoric”, the present paper has a twofold purpose. On the one hand, it aims to import a clear taxonomy of rhetorical figures from advertising into translation studies and subsequently to illustrate the transfer of these figures. On the other hand, it analyses the behaviour of rhetorical figures in the translation process by means of an empirical investigation whose goal it is to further categorise them in a systematic and rational way. Drawing upon the seminal work of McQuarrie and his collaborators, the paper performs a quantitative analysis of a corpus of 120 matching pairs consisting of English advertisements and their existing Spanish counterparts. Results evidence that a great majority of rhetorical figures are “translated”, thus confirming the globalising tendencies of advertising.
“Eorlas arhwate eard begeatan”
Authors: Bueno-Alonso Jorge L.
Published: May 2011

The poetic insert known as The Battle of Brunanburh (Anglo-Saxon Chronicle 937) constitutes by no means one of the most interesting texts for the building of the Old English heroic geography. Its author, as Marsden states (2005: 86), “builds a sense of national destiny, using style, diction and imagery of heroic poetry”. There are many interesting issues to deal with when you want to revise how the elements Marsden quotes are used in the construction of a poem that uses history as a narrative device to build the inner story of the poem experimenting with the topics (style, diction, imagery) of heroic poetry. If the poem constitutes such a crucial text, if its emphasis is on “English nationalism” in an historical perspective rather than on individual heroics, as Marsden points out (2005: 86), it seems most evident that a careful consideration of these topics has to be made when translating the text into other languages. The aim of this article is to revisit the poem and its topics and to see how that careful consideration has been accomplished in several important English (Treharne 2004, Hamer 1970, Rodrigues 1996, Garmonsway 1953, Swanton 2000) and Spanish (Lerate & Lerate 2000, Bravo 1998, Bueno 2007) translations that consider the poem in isolation, in the context of the Anglo-Saxon Chronicle or as an excuse for poetic inspiration, i.e. the case of Borges’ 1964 and 1975 poems and Tennyson’s 1880 text.
From left to right and from right to left
Authors: Kayyal Mahmoud
Published: May 2011

The present paper discusses Anton Shammas’s translations of Modern Hebrew literature into Arabic and of Modern Arabic literature into Hebrew. The discussion focuses on the connection between hegemony and translation, particularly in light of the fact that these translations were carried out in the shadow of the political, social and economic hegemony of the Jewish majority over the Arab-Palestinian minority in Israel. Shammas began his translation activities with a series of translations from Hebrew into Arabic, but after establishing his status in Hebrew literature and journalism, he began to translate from Arabic into Hebrew as well. Evidently, this transition entailed a significant change in his translation paradigm and in his attitude toward the culture of the hegemonic majority.
His translations from Hebrew into Arabic aimed to preserve and reinforce that hegemony, not only through the direct or indirect involvement of bodies from the source culture and bodies identified with the establishment, but also in the multiple interferences of the Hebrew source language in the Arabic target language, and his disregard for the accepted linguistic, stylistic and ethical norms of the Arab target culture. By contrast, Shammas’s translations from Arabic into Hebrew aimed to challenge the discourse of the hegemonic culture through his meticulous selection of works that represent the oppressed narrative of the Palestinian people and adopting translation policies to enhance acceptability in the target culture, such as non-preservation of the integrity of the source text in the translation, elevation of linguistic and stylistic register in the translated text, and an inclination toward paraphrase.
Erik Sahai: Getting the whole picture of metastasis
Authors: Sedwick Caitlin
Published: May 2011

Sahai uses 3D culture and intravital imaging to investigate how tumor cells invade surrounding tissues.