bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppressed, but Not Forgotten
Authors: Meier Beat , König Anja , Parak Samuel , Henke Katharina
Published: February 2011

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.
On the Intra- and Interindividual Differences in the Meaning of Smileys
Authors: Elfering Achim , Grebner Simone
Published: February 2011

There is increasing evidence that the Faces Scale is more sensitive to the emotional component of job satisfaction than other scales. This study investigated underlying processes and tested whether state affect and neuroticism covary with respondents’ evaluations of each face’s meaning. Seventy-five participants repeatedly judged single schematic faces as looking satisfied or unsatisfied. Participants made 11,025 two-alternative, forced-choice judgments about a variety of eleven faces. Results showed that faces appeared more satisfied to those who reported good mood and lower neuroticism (assimilation effect). In addition, there was a significant range effect of scale composition: In a range including five smiling faces, a face showing a mild smile was more often judged as looking unsatisfied than in a range including five frowning faces. Moreover, a significant interaction between range and neuroticism indicated stronger range effects in those participants who reported higher neuroticism than others. The implications for the use of the Faces Scale in work and organizational psychology are discussed.
Theoretical studies of the N2O van der Waals dimer: Ab initio potential energy surface, intermolecular vibrations and rotational transition frequencies
Authors: Zheng Limin , Lu Yunpeng , Lee Soo-Ying , Fu Hong , Yang Minghui
Published: February 2011

Theoretical studies of the potential energy surface and bound states were performed for the N2O dimer. A four-dimensional intermolecular potential energy surface (PES) was constructed at the CCSD(T) level with aug-cc-pVTZ basis set supplemented with bond functions. Three co-planar local minima were found on this surface. They correspond to a nonpolar isomer with slipped-antiparallel planar structure and two equivalent polar isomers with slipped-parallel planar structures. The nonpolar isomer is energetically more stable than the polar ones by 162 cm−1. To assign the fundamental vibrational frequencies for both isomers, more than 150 vibrational bound states were calculated based on this PES. The orientation of the nodal surface of the wave functions plays an important role in the assignment of disrotation and conrotation vibrational modes. The calculated vibrational frequencies are in good agreement with the available experimental data. We have also found a quantum tunneling effect between the two equivalent polar structures in the higher vibrational excited states. Rotational transition frequencies of the polar structure were also calculated. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters.
Experimental characterization and modeling of a nanofiber-based selective emitter for thermophotovoltaic energy conversion: The effect of optical properties
Authors: Aljarrah M. T. , Wang R. , Evans E. A. , Clemons C. B. , Young G. W.
Published: February 2011

Aluminum oxide nanofibers doped with erbium oxide have been synthesized by calcining polymer fibers made by the electrospinning technique using a mixture of aluminum acetate, erbium acetate and polyvinylpyrrolidone dissolved in ethanol. The resulting ceramic fibers are used to fabricate a free-standing selective emitter. The general equation of radiation transfer coupled with experimentally measured optical properties is used to model the net radiation obtained from these structures. It has been found that the index of refraction and the extinction coefficient are direct functions of the erbia doping level in the fibers. The fibers radiated in a selective manner at ∼1.53 μm with an efficiency of about 90%. For a fiber film on a substrate, the effect of film thickness, extinction coefficient and substrate emissivity on the overall emitter emissivity is also investigated in this study. Results show that the emissivity of the film increases as the thickness of the film increases up to a maximum value, after which increasing the film thickness had no effect on emissivity. Furthermore, it has been found that the substrate emissivity increases the amount of off-band radiation. This effect can be mitigated by controlling the film thickness.
Modeling of emission properties from a spatially distributed selective emitter
Authors: Aljarrah M. T. , Evans E. A. , Hicks J. , Clemons C. B. , Young G. W.
Published: February 2011

Preliminary analyses are presented to examine how the geometric distribution of rare-earth material in a thin film selective emitter influences the net emission. The general one-dimensional equation of radiation transfer is considered under the assumption of negligible rescattering by eliminating the phase function term. Due to the large value of the absorption coefficient for the materials under discussion, the diffusion approximation to this equation is used. Homogenization techniques are applied to this diffusion approximation to define expressions for the effective absorption and scattering coefficients for a spatially distributed selective emitting film. The emitting film consists of alternating layers of emitting and nonemitting materials into a form we call stacked layers. The optical properties of the individual layers are determined experimentally. These properties are input into the effective expressions for the absorption and scattering coefficients. The effective expressions are input into the general one-dimensional equation of radiation transfer to model the net radiation obtained from these emitting structures in directions parallel and perpendicular to the stacked layers. Results show that the emissivity of the film along the parallel direction of the stacked layers exceeds that along the perpendicular direction. Further, a film consisting of stacked layers with half the volume fraction of emitting material emits radiation along the parallel direction that is quantitatively comparable to the emission from a film consisting of a single layer of only emitting material. Hence, the reduction in emitting material may lead to a drop in the weight of the device and to lower costs.
Note: Production of sharp gold tips with high surface quality
Authors: Eisele Max , Krüger Michael , Schenk Markus , Ziegler Alexander , Hommelhoff Peter
Published: February 2011

We present a simple method to produce sharp gold tips with excellent surface quality based on electrochemical etching with potassium chloride. Radii of curvature lie in the range of 20–40 nm and the surface roughness is measured to less than 0.8 nm. The tips are well suited for field emission, field ion microscopy, and likely for tip-enhanced Raman scattering as well as tip-enhanced near-field imaging.
In situ optical microspectroscopy approach for the study of metal transport in dielectrics via temperature- and time-dependent plasmonics: Ag nanoparticles in SiO2 films
Authors: Jiménez José A. , Sendova Mariana
Published: February 2011

This study proposes in situ optical microspectroscopy as a means for the investigation of particle growth and metal transport in nanocomposite systems based on the temperature- and time-dependent optical response of the material. The technique has been successfully employed for the real-time monitoring of the growth of Ag nanoparticles (NPs) in SiO2 films deposited on soda-lime glass during thermal processing in nitrogen atmosphere. By fitting the surface plasmon resonance (SPR) profiles with spectra calculated by Mie theory in the quasi-static regime, the time variation in effective Ag particle size was determined and subsequently analyzed in the context of crystal growth theory. The Ag NPs were indicated to grow first through a diffusion-based process and subsequently via Ostwald ripening. The experimental determination of the activation energies associated with each one of the particle growth mechanisms was carried out based on the time evolution of the SPR of Ag NPs. Arrhenius-type analyses of a set of time-dependent isotherms allowed for estimating the activation energies at 2.3 eV for the diffusion-based growth and 2.8 eV for the ripening stage.
Modeling of gain recovery of quantum cascade lasers
Authors: Talukder Muhammad Anisuzzaman
Published: February 2011

We present a model to calculate the gain recovery of quantum cascade lasers (QCLs). We implement the model for two QCLs with different material systems and quantum mechanical designs. It is found that both incoherent scattering and coherent tunneling are important for gain recovery, however, their relative importance depends on the material systems, quantum mechanical designs, and operating conditions. Though details of the gain recovery vary for the two QCLs, a complete gain recovery takes ∼2 ps in both cases. The results are consistent with the results found in pump-probe experiments.
Darboux covariant Lax pairs and infinite conservation laws of the (2+1)-dimensional breaking soliton equation
Authors: Fan Engui , Chow Kwok Wing
Published: February 2011

In this paper, the binary Bell polynomials are applied to succinctly construct bilinear formulism, bilinear Bäcklund transformations, Lax pairs, and Darboux covariant Lax pairs for the (2+1)-dimensional breaking soliton equation. An extra auxiliary variable is introduced to get the bilinear formulism. The infinitely local conservation laws of the equation are found by virtue of its Lax equation and a generalized Miura transformation. All conserved densities and fluxes are given with explicit recursion formulas.
On a kind of Noether symmetries and conservation laws in k-cosymplectic field theory
Authors: Marrero Juan Carlos , Román-Roy Narciso , Salgado Modesto , Vilariño Silvia
Published: February 2011

This paper is devoted to studying symmetries of certain kinds of k-cosymplectic Hamiltonian systems in first-order classical field theories. Thus, we introduce a particular class of symmetries and study the problem of associating conservation laws to them by means of a suitable generalization of Noether's theorem.
Off-shell nilpotent finite Becchi–Rouet–Stora–Tyutin (BRST)/anti-BRST transformations
Authors: Upadhyay Sudhaker , Rai Sumit Kumar , Mandal Bhabani Prasad
Published: February 2011

We develop the off-shell nilpotent finite field dependent Becchi–Rouet–Stora–Tyutin (BRST) transformations and show that for different choices of the finite field dependent parameter these transformations connect the generating functionals corresponding to different effective theories. We also construct both on-shell and off-shell finite field dependent anti-BRST transformations for Yang–Mills theories and show that these transformations play the similar role in connecting different generating functionals of different effective theories. Analogous to the finite field dependent BRST transformations, the nontrivial Jacobians of the path integral measure which arise due to the finite field dependent anti-BRST transformations are responsible for the new results. We consider several explicit examples in each case to demonstrate the results.
A Hom-version of the affinizations of Balinskii–Novikov and Novikov superalgebras
Authors: Zhang Runxuan , Hou Dongping , Bai Chengming
Published: February 2011

In this paper, we introduce the notions of Hom-Balinskii–Novikov and Hom-Novikov superalgebras, in which the defining identities are twisted by homomorphisms. Then we construct some infinite-dimensional Hom-Lie superalgebras by the affinizations of the above two Hom-superalgebras. Moreover, we apply the bilinear forms with some invariance conditions on the Hom-Balinskii–Novikov and Hom-Novikov superalgebras to construct central extensions of the infinite-dimensional Hom-Lie superalgebras.
NO+ formation pathways in dissociation of N2O+ ions at the C2Σ+ state revealed from threshold photoelectron–photoion coincidence velocity imaging
Authors: Tang Xiaofeng , Niu Mingli , Zhou Xiaoguo , Liu Shilin , Liu Fuyi , Shan Xiaobin , Sheng Liusi
Published: February 2011

Using the novel threshold photoelectron–photoion coincidence (TPEPICO) velocity imaging technique, the dissociative photoionization of N2O molecule via the C2Σ+ ionic state has been investigated. Four fragment ions, NO+, N2+, O+, and N+, are observed, respectively, and the NO+ and N+ ions are always dominant in the whole excitation energy range of the C2Σ+ ionic state. Subsequently, the TPEPICO three-dimensional time-sliced velocity images of NO+ dissociated from the vibrational state-selected N2O+(C2Σ+) ions have been recorded. Thus the kinetic and internal energy distributions of the NO+ fragments have been obtained directly as the bimodal distributions, suggesting that the NO+ fragments are formed via both NO+(X1Σ+) + N(2P) and NO+(X1Σ+) + N(2D) dissociation channels. Almost the same vibrational population reversions are identified for both dissociation pathways. Interestingly, the obtained branching ratios of the two channels exhibit some dependence on the excited vibrational mode for N2O+(C2Σ+), in which the excited asymmetrical stretching potentially promotes dissociation possibility along the NO+(X1Σ+) + N(2D) pathway. In addition, the measured anisotropic parameters of NO+ are close to 0.5, indicating that the C2Σ+ state of N2O+ is fully predissociative, indeed, with a tendency of parallel dissociation, and therefore, the corresponding predissociation mechanisms for the N2O+(C2Σ+) ions are depicted.
Impact of electromagnetic radiation on cascaded failure in high voltage insulators
Authors: Bojovschi A. , Wong K. L. , Rowe W. S. T.
Published: February 2011

A cause of aging and cascaded failure of high voltage insulators is investigated by assessing the radiation propagating from a faulty insulator. The transfer of electromagnetic energy from corona discharge to healthy insulators situated on the same power pole is assessed. The results show that the high intensity of electric field associated with corona discharge on faulty insulators can lead to aging and finally failure of high voltage infrastructure.
Adiabatic charge control in a single donor atom transistor
Authors: Prati Enrico , Belli Matteo , Cocco Simone , Petretto Guido , Fanciulli Marco
Published: February 2011

We charge an individual donor quantum dot with an electron originally stored in another quantum dot in its proximity. The single arsenic donor quantum dot and the electrostatic quantum dot in parallel are contained in a silicon nanometric field effect transistor. Their different coupling capacitances with the control and back gates determine a honeycomb pattern at high control gate voltage. It is therefore possible to control the exchange coupling of an electron of the quantum dot with the electrons bound to the donor quantum dot toward the realization of a physical qubit for quantum information processing applications.
Hydrodynamically mediated breakup of droplets in microchannels
Authors: Che Zhizhao , Nguyen Nam-Trung , Wong Teck Neng
Published: February 2011

A flow focusing junction is integrated into a microchannel to break up droplets into a controllable number and size of daughter droplets. High speed images of the breakup at the flow focusing junction show that the breakup depends on the interplay between interfacial tension, shear force on the interface, and the confinement of the microchannel. Phase diagrams of the splitting performance show that the breakup is controllable by varying the flow rate of the continuous phase or by varying the size of the mother droplet.
Vertical polymer phototransistor featuring photomultiplication due to base-field shielding
Authors: Zan Hsiao-Wen , Tsai Wu-Wei , Meng Hsin-Fei
Published: February 2011

We introduce a vertical polymer phototransistor with low operational voltage (−1.5 V). A blended polymer layer with both acceptor and donor materials was used as a channel material in the vertical space-charge-limited transistor. Under illumination, we obtained external quantum efficiency (EQE) as high as 360% at 620 nm. We propose the effects of base-field shielding as a means to explain high EQE. This proposition has been supported by two-dimensional simulation of the device.
Large room temperature magnetoresistance in ion beam synthesized surface Fe nanoclusters on SiO2
Authors: Leveneur J. , Kennedy J. , Williams G. V. M. , Metson J. , Markwitz A.
Published: February 2011

A large room temperature magnetoresistance ratio of up ∼40% at 8 T is observed in ion beam synthesized surface Fe nanoclusters on SiO2 where there is negligible hysteresis, and quasilinear behavior occurs for fields above 2 T. The negligible hysteresis can be attributed to the small dimensions of the Fe nanoparticles that are superparamagnetic with blocking temperatures ranging from 170 to 250 K. The large magnetoresistance is likely to be due to a combination of geometric and extraordinary magnetoresistances as well as spin-dependent scattering. The observed properties have great potential for magnetic sensing in the high field regime.
Size effect on the coalescence-induced self-propelled droplet
Authors: Wang Feng-Chao , Yang Fuqian , Zhao Ya-Pu
Published: February 2011

An analysis based on the energy conservation is presented for the self-propelled droplet during coalescence of two droplets of the same size over a superhydrophobic rough surface. The self-propelled behavior occurs only for the coalescence of droplets with a certain range of radius. An analytical relation is established among the coalescence-induced velocity, surface energy, viscous dissipation, and droplet size if gravity is negligible. The coalescence-induced velocity increases with increasing droplet size to a maximum and then decreases with the size, which is in good accord with the experimental observation reported in the literature.
Identification of a major cause of endemically poor mobilities in SiC/SiO2 structures
Authors: Shen Xiao , Pantelides Sokrates T.
Published: February 2011

Poor electron mobility at SiC/SiO2 interfaces has long held up the development of SiC-based power devices. The mobility degradation has been attributed to defects at the interface and the oxide as in the case of the Si/SiO2 system, but a decade of research has led only to limited improvement. Here we examine theoretical results and available experimental evidence and show that thermal oxidation generates immobile carbon di-interstitial defects inside the semiconductor substrate and that they are a major cause of the poor mobility in SiC/SiO2 structures.
Remedial options for copper-contaminated vineyard soils
Authors: Pietrzak U. , Uren N. C.
Published: February 2011

Total copper concentrations in some Victorian vineyard soils, due to the use of copper (Cu)-based fungicides, have increased to the point where remedial strategies need to be considered to avoid Cu toxicity. In Australia, the National Environment Protection (Assessment of Site Contamination) Measure recommends that total Cu concentrations in soil exceeding the threshold concentration of 100 mg/kg require environmental investigation. However, it is likely that some Cu-contaminated soils, to be used for horticultural purposes, will need to be remediated even if the total Cu concentration is <100 mg/kg. This paper examines some prospective remedial strategies for Cu-contaminated vineyard soils and demonstrates that, apart from stopping the addition of Cu, in situ remedial strategies are the only practical remedial options for Cu-contaminated vineyard soils. Active mixing, both lateral and vertical, of contaminated surface soil with less contaminated or uncontaminated deeper soil is an in situ and well-suited remedial option for most low and medium Cu-contaminated vineyard soils. The strategy relies on attenuation processes to be more effective. Other ameliorative strategies with potential as remedial options for low and medium Cu-contaminated soils, including phytoremediation and attenuation (liming and addition of organic matter), are also considered.
Evaluation of the effects of cation combinations on soil hydraulic conductivity
Authors: Jayawardane N. S. , Christen E. W. , Arienzo M. , Quayle W. C.
Published: February 2011

Effects of soil solution cation concentrations and ratios on hydraulic properties must be understood in order to model soil water flow in reactive soils or develop guidelines for sustainable land application of wastewater. We examined effects of different ratios and concentrations of the cations Ca2+, Mg2+, Na+, and K+, using hydraulic conductivity measurements in repacked soil cores, as an indicator of soil structural stability. We examined widely used indices—sodium, potassium, and monovalent cation absorption ratios (SAR, PAR, MCAR)—which assume that the flocculating effects of Ca2+ and Mg2+ are the same, and the dispersive effects of Na+ and K+ are the same. Our laboratory measurements indicate that at any given values of MCAR, the reductions in soil hydraulic conductivity with decrease in electrolyte concentration are not identical for different cation combinations in solution. The hydraulic conductivity curves showed a marked lateral shifting for both the surface and subsurface soils from a winery wastewater application site. This indicates that MCAR is inadequate as a soil stability parameter in soil solutions containing a mixture of Na+, K+, Ca2+, and Mg2+.
We employed an unpublished equation that was proposed by P. Rengasamy as a modified index of soil stability for mixed cation combinations, using calculated relative flocculating powers of different cations (‘CROSS’, cation ratio of structural stability). Our observation of lateral shift in hydraulic conductivity measurements at any value of MCAR appears to relate to changes in CROSS values for all cation combinations tested, except for K–Mg solutions, for which a more generalised CROSS equation with modified parameters seems more suitable for calculating the CROSS value. Appropriate modified parameters for use in this generalised CROSS equation were determined empirically, using the experimental data.
We derived a combination of threshold electrolyte concentration and CROSS values required to maintain high hydraulic conductivity for the soils at a winery wastewater application site. The potential use of this relationship in developing management practices for sustainable wastewater management at the site is discussed. Further research on the applicability of CROSS and generalised CROSS equations for other soils in the presence of different mixed cation combinations is needed.
Temporal variability of soil water storage evaluated for a coffee field
Authors: Timm L. C. , Dourado-Neto D. , Bacchi O. O. S. , Hu W. , Bortolotto R. P. , Silva A. L. , Bruno I. P. , Reichardt K.
Published: February 2011

Sampling field soils to estimate soil water content and soil water storage (S) is difficult due to the spatial variability of these variables, which demands a large number of sampling points. Also, the methodology employed in most cases is invasive and destructive, so that sampling in the same positions at different times is impossible. However, neutron moderation, time domain reflectrometry, and, more recently, frequency domain reflectrometry methodologies allow measurements at the same points over long time intervals. This study evaluates a set of neutron probe data, collected at 15 positions placed randomly along a coffee crop contour line, over 2 years at 14-day intervals. The temporal stability of S was again demonstrated, so that wetter or dryer locations remain so over time, and the definition of such positions in the field reduces the number of sampling points in future S evaluations under similar conditions. An analysis was made to determine the minimum number of sampling points to obtain the average S of the field within a chosen level of significance. Classical statistical analysis indicated that the 15 measurement positions could be reduced to four or even to one position to obtain a reliable field S average. State–time analysis showed S estimations depend more on previous measurements of rainfall P (52%) than on evapotranspiration ET (28%) and S (20%). The analysis also showed that ET was not realistically estimated from previous measurements of S; it was more dependent on previous measurements of ET (59%) than on P (30%) and S (9%). This statistical procedure showed great advantages over classical multiple regressions. Future studies of this type should be carried out at regularly spaced observation points in a grid, in order to allow a 2-D and 3-D state–space–time analysis.
Factors affecting apparent 15N fractionation during nitrogen mineralisation in soils with different root litter inputs
Authors: Sierra Jorge , Desfontaines Lucienne
Published: February 2011

Nitrogen-15 (15N) fractionation during N mineralisation is frequently invoked to interpret data of N cycling in N-isotope-based ecosystem studies. Because direct measurement of actual fractionation (Dact) is difficult to perform, it is currently estimated from laboratory or field incubation experiments (apparent fractionation, Dapp). However, the procedure of calculation may induce bias in the estimations due to several factors controlled by litter inputs. The objective of this study was to assess the effects of litter inputs and the size and 15N content of organic N fractions on Dapp. Laboratory incubations were performed using soils receiving different amount of root litter from legume trees and grass in an agroforestry plot. The 15N contents of organic N and mineralised N were determined. The results were interpreted with a ‘three-N’ pool model considering two labile organic N pools derived from litter of the tree and the grass, and a recalcitrant organic N pool comprising organic N in mineral soil. The model was used to explore mechanisms that could explain the Dapp obtained in the incubation experiment. Model simulations well duplicated the observed relationships between organic N, mineralised N, their 15N content, and Dapp. Dapp varied from 1.2‰ to 2.4‰. It was negatively correlated with the distance from trees (R2 = 0.91, P < 0.05) and positively correlated with total organic N (R2 = 0.81, P < 0.05). Model simulations indicated that these correlations did not reflect a control of 15N fractionation, but were an artefact induced by the higher decomposition rate of the labile organic N depleted in 15N. This induced an overestimation of 15N fractionation that varied from 10% to 55%. Our results indicated that the procedure currently applied to estimate 15N fractionation during mineralisation may induce large overestimations depending upon the amount of litter input, and the size and 15N content of the organic N pools.
Assessing carbon lability of particulate organic matter from δ13C changes following land-use change from C3 native vegetation to C4 pasture
Authors: Dalal R. C. , Cowie B. A. , Allen D. E. , Yo S. A.
Published: February 2011

Land-use change from C3 vegetation (δ13C values, –30‰ to –24‰) to C4 vegetation (δ13C values, –14‰ to –11‰) provides a useful quantitative technique for estimating organic C turnover in soil, even when total organic C changes are negligible. We utilised this technique to estimate C turnover in physically fractionated soil organic matter, particulate organic matter C (POM C >250 μm fraction and POM C 250–53 μm fraction), and the <53 μm fraction. There were small changes in total soil organic C (SOC) after 23 years of land-use change from native vegetation (mixed vegetation of Acacia harpophylla and Casuarina cristata) to buffel grass (Cenchrus ciliaris L. cv. Biloela) pasture grown on Vertosol–Dermosol–Sodosol soil types. The SOC values (t/ha) under native vegetation were: 31 ± 3 for the 0–0.1 m depth, 21 ± 1 for the 0.1–0.2 m depth, 15 ± 3 for the 0.2–0.3 m depth, and 16 ± 2 for the 0.3–0.4 m depth; the corresponding SOC values under pasture were 25 ± 2, 19 ± 2, 14 ± 2, and 13 ± 1 t/ha. The respective δ13C values in 0–0.1 m depths of the whole SOC and POM C >250 μm fraction changed from –25.5 ± 0.1‰ and –25.5 ± 0.3‰ under native vegetation to –20.1 ± 0.5‰ and –19.4 ± 0.2‰ under pasture. Similar, although smaller, differences were observed for other depths and SOC fractions. The SOC turnover periods (years) were 31 ± 6 for the 0–0.1 m depth, 60 ± 5 for the 0.1–0.2 m depth, 55 ± 15 for the 0.2–0.3 m depth, and 63 ± 20 for the 0.3–0.4 m depth; the corresponding turnover periods for the POM C >250 μm fraction were 13 ± 2, 19 ± 5, 14 ± 4, and 12 ± 5 years. The turnover periods of SOC in the POM C 250–53 μm and <53 μm fractions were similar to, or longer than, for the whole SOC at all depths studied. Thus, the lability of the SOC and SOC pools was in the order: POM C >250 μm fraction > POM C 53–250 μm fraction = POM C <53 μm fraction = whole SOC.
Ribosome recycling depends on a mechanistic link between the FeS cluster domain and a conformational switch of the twin-ATPase ABCE1
Authors: Barthelme Dominik , Dinkelaker Stephanie , Albers Sonja-Verena , Londei Paola , Ermler Ulrich , Tampé Robert
Published: February 2011

Despite some appealing similarities of protein synthesis across all phyla of life, the final phase of mRNA translation has yet to be captured. Here, we reveal the ancestral role and mechanistic principles of the newly identified twin-ATPase ABCE1 in ribosome recycling. We demonstrate that the unique iron-sulfur cluster domain and an ATP-dependent conformational switch of ABCE1 are essential both for ribosome binding and recycling. By direct (1∶1) interaction, the peptide release factor aRF1 is shown to synergistically promote ABCE1 function in posttermination ribosome recycling. Upon ATP binding, ABCE1 undergoes a conformational switch from an open to a closed ATP-occluded state, which drives ribosome dissociation as well as the disengagement of aRF1. ATP hydrolysis is not required for a single round of ribosome splitting but for ABCE1 release from the 30S subunit to reenter a new cycle. These results provide a mechanistic understanding of final phases in mRNA translation.
Antigen-stimulated CD4 T-cell expansion is inversely and log-linearly related to precursor number
Authors: Quiel Juan , Caucheteux Stephane , Laurence Arian , Singh Nevil J. , Bocharov Gennady , Ben-Sasson Shlomo Z. , Grossman Zvi , Paul William E.
Published: February 2011

Antigen-driven expansion of specific CD4 T cells diminishes, on a per cell basis, as infused cell number increases. There is a linear relation between log precursor number and log factor of expansion (FE), with a slope of ∼−0.5 over a range from 3 to 30,000 precursors. Cell number dependence of FE is observed at low precursor number, implying that the underlying process physiologically regulates antigen-driven T-cell expansion. FE of small numbers of transgenic precursors is not significantly affected by concomitant responses of large numbers of cells specific for different antigens. Increasing antigen amount or exogenous IL-2, IL-7, or IL-15 does not significantly affect FE, nor does FE depend on Fas, TNF-α receptor, cytotoxic T-lymphocyte antigen-4, IL-2, or IFN-γ. Small numbers of Foxp3-deficient T-cell receptor transgenic cells expand to a greater extent than do large numbers, implying that this effect is not mediated by regulatory T cells. Increasing dendritic cell number does result in larger FE, but the quantitative relation between FE and precursor number is not abrogated. Although not excluding competition for peptide/MHC complexes as an explanation, fall in FE with increasing precursor number could be explained by a negative feedback in which increasing numbers of responding cells in a cluster inhibit the expansion of cells of the same specificity within that cluster.
Feedback regulation of proliferation vs. differentiation rates explains the dependence of CD4 T-cell expansion on precursor number
Authors: Bocharov Gennady , Quiel Juan , Luzyanina Tatyana , Alon Hagit , Chiglintsev Egor , Chereshnev Valery , Meier-Schellersheim Martin , Paul William E. , Grossman Zvi
Published: February 2011

The mechanisms regulating clonal expansion and contraction of T cells in response to immunization remain to be identified. A recent study established that there was a log-linear relation between CD4 T-cell precursor number (PN) and factor of expansion (FE), with a slope of ∼−0.5 over a range of 3–30,000 precursors per mouse. The results suggested inhibition of precursor expansion either by competition for specific antigen-presenting cells or by the action of other antigen-specific cells in the same microenvironment as the most likely explanation. Several molecular mechanisms potentially accounting for such inhibition were examined and rejected. Here we adopt a previously proposed concept, “feedback-regulated balance of growth and differentiation,” and show that it can explain the observed findings. We assume that the most differentiated effectors (or memory cells) limit the growth of less differentiated effectors, locally, by increasing the rate of differentiation of the latter cells in a dose-dependent manner. Consequently, expansion is blocked and reversed after a delay that depends on initial PN, accounting for the dependence of the peak of the response on that number. We present a parsimonious mathematical model capable of reproducing immunization response kinetics. Model definition is achieved in part by requiring consistency with available BrdU-labeling and carboxyfluorescein diacetate succinimidyl ester (CFSE)-dilution data. The calibrated model correctly predicts FE as a function of PN. We conclude that feedback-regulated balance of growth and differentiation, although awaiting definite experimental characterization of the hypothetical cells and molecules involved in regulation, can explain the kinetics of CD4 T-cell responses to antigenic stimulation.
Under-reported and undervalued: small-scale fisheries in the developing world.
Authors: Mills D. J. , Westlund L. , Graaf G. de , Kura Y. , Willman R. , Kelleher K.
Published: February 2011

This chapter discusses the collection of data on small-scale fisheries in developing countries, the limitations of national data systems and progress in synthesizing collected data.
Diagnosis and the management constituency of small-scale fisheries.
Authors: Evans L. , Andrew N. L.
Published: February 2011

The concepts and implementation of the Participatory Diagnosis and Adaptive Management (PDAM) framework for small-scale fishery development and management in developing countries are described.
Human rights and fishery rights in small-scale fisheries management.
Authors: Charles A.
Published: February 2011

The aspects of human rights and fishery rights, the relationship between the two, the implementation of rights and the creation of rights framework in small-scale fisheries management are discussed.
Managing overcapacity in small-scale fisheries.
Authors: Pomeroy R. S.
Published: February 2011

The concept and assessment of overcapacity, overfishing and sustainability of small-scale marine fisheries and the socioeconomic effects on fishing communities are discussed.
Adaptive management in small-scale fisheries: a practical approach.
Authors: Parks J.
Published: February 2011

This chapter discusses the origins, theory, design and implementation of adaptive management in small-scale fisheries.
Conditions for successful co-management: lessons learned in Asia, Africa, the Pacific and the Wider Caribbean.
Authors: Pomeroy R. S. , Cinner J. E. , Nielsen J. R.
Published: February 2011

The key conditions for the successful implementation and performance and the policy implications for fisheries and coastal co-management in South East Asia, Africa, the Pacific and Caribbean region are presented.
Communication.
Authors: McConney P. , Haynes C.
Published: February 2011

The definition, effectiveness and roles of communication, communication strategies, communication-based processes and specific media guidelines in small-scale fisheries management are presented.
Poverty reduction as a means to enhance resilience in small-scale fisheries.
Authors: Allison E. H. , Béné C. , Andrew N. L.
Published: February 2011

This chapter examines the multiple dimensions of poverty and related 'state of being' such as vulnerability and social exclusion, with reference to several important aspects of vulnerability, including gender, climate change, HIV/AIDS and child labour.
Evaluation of hydrogen atom density in the plasma core region based on the Balmer-𝛂 line profile
Authors: Goto M. , Sawada K. , Fujii K. , Hasuo M. , Morita S.
Published: February 2011

The Balmer-α line profile is measured with high wavelength resolution for a discharge in the Large Helical Device. The line profile is regarded as a superposition of continuously varying Doppler broadened components and is expressed as the Laplace transform. Numerical Laplace inversion of the measured line profile gives the distribution function of line emissivity in terms of atom temperature. The temperature dependence of the line emissivity is interpreted as spatial dependence so that the ionization rate and atom density of neutral hydrogen are determined. The temperature range of the detected atoms extends beyond 2 keV which corresponds to a penetration depth of about 1 m in the plasma, or the location at ρ ∼ 0.3, where ρ is the normalized minor radius. The atom density of approximately 1013 m−3 is derived in the plasma core region which is more than four orders smaller than that at the plasma boundary. Calculation of neutral transport with a Monte-Carlo simulation code gives satisfactory consistency with the experimental results.
Some generalized Euclidean and 2-stage Euclidean number fields that are not norm-Euclidean
Authors: Cerri Jean-Paul
Published: February 2011

We give examples of Generalized Euclidean but not norm-Euclidean number fields of degree greater than 2. In the same way we give examples of 2-stage Euclidean but not norm-Euclidean number fields of degree greater than 2. In both cases, no such examples were known.
Involvement of the Lateral Amygdala in the Antiallodynic and Reinforcing Effects of Heroin in Rats after Peripheral Nerve Injury
Authors: Martin Thomas J. , Buechler Nancy L. , Kim Susy A. , Ewan Eric E. , Xiao Ruoyu , Childers Steven R.
Published: February 2011

Background

Neuropathic pain alters opioid self-administration in rats. The brain regions altered in the presence of neuropathic pain mediating these differences have not been identified, but likely involve ascending pain pathways interacting with the limbic system. The amygdala is a brain region that integrates noxious stimulation with limbic activity.

Methods

μ-Opioid receptors were blocked in the amygdala using the irreversible antagonist, β-funaltrexamine, and the antiallodynic and reinforcing effects of heroin were determined in spinal nerve-ligated rats. In addition, the effect of β-funaltrexamine was determined on heroin self-administration in sham-operated rats.

Results

β-Funaltrexamine decreased functional activity of μ-opioid receptors by 60 ± 5% (mean ± SD). Irreversible inhibition of μ-opioid receptors in the amygdala significantly attenuated the ability of doses of heroin up to 100 μg/kg to reverse hypersensitivity after spinal nerve ligation. Heroin intake by self-administration in spinal nerve-ligated rats was increased from 5.0 ± 0.3 to 9.9 ± 2.1 infusions/h after administration of 2.5 nmol of β-funaltrexamine in the lateral amygdala, while having no effect in sham-operated animals (5.8 ± 1.6 before, 6.7 ± 0.9 after). The antiallodynic effects of 60 μg/kg heroin were decreased up to 4 days, but self-administration was affected for up to 14 days.

Conclusions

μ-Opioid receptors in the lateral amygdala partially meditate heroin's antiallodynic effects and self-administration after peripheral nerve injury. The lack of effect of β-funaltrexamine on heroin self-administration in sham-operated subjects suggests that opioids maintain self-administration through a distinct mechanism in the presence of pain.
Opioid Facilitation of Rewarding Electrical Brain Stimulation Is Suppressed in Rats with Neuropathic Pain
Authors: Ewan Eric E. , Martin Thomas J.
Published: February 2011

Introduction

Opioids are powerful analgesics, but are also common drugs of abuse. Few studies have examined how neuropathic pain alters the pharmacology of opioids in modulating limbic pathways that underlie abuse liability.

Methods

Rats with or without spinal nerve ligation (SNL) were implanted with electrodes into the left ventral tegmental area and trained to lever press for electrical stimulation. The effects of morphine, heroin, and cocaine on facilitating electrical stimulation of the ventral tegmental area and mechanical allodynia were assessed in SNL and control subjects.

Results

Responding for electrical stimulation of the ventral tegmental area was similar in control and SNL rats. The frequency at which rats emitted 50% of maximal responding was 98.2 ± 5.1 (mean ± SEM) and 93.7 ± 2.8 Hz in control and SNL rats, respectively. Morphine reduced the frequency at which rats emitted 50% of maximal responding in control (maximal shift of 14.8 ± 3.1 Hz), but not SNL (2.3 ± 2.2 Hz) rats. Heroin was less potent in SNL rats, whereas cocaine produced similar shifts in control (42.3 ± 2.0 Hz) and SNL (37.5 ± 4.2 Hz) rats.

Conclusions

Nerve injury suppressed potentiation of electrical stimulation of the ventral tegmental area by opioids, suggesting that the positive reinforcing effects are diminished by chronic pain. Given concerns regarding prescription opioid abuse, developing strategies that assess both analgesia and abuse liability within the context of chronic pain may aid in determining which opioids are most suitable for treating chronic pain when abuse is a concern.
Strategies for antiviral stockpiling for future influenza pandemics: a global epidemic-economic perspective
Authors: Carrasco Luis R. , Lee Vernon J. , Chen Mark I. , Matchar David B. , Thompson James P. , Cook Alex R.
Published: February 2011

Influenza pandemics present a global threat owing to their potential mortality and substantial economic impacts. Stockpiling antiviral drugs to manage a pandemic is an effective strategy to offset their negative impacts; however, little is known about the long-term optimal size of the stockpile under uncertainty and the characteristics of different countries. Using an epidemic–economic model we studied the effect on total mortality and costs of antiviral stockpile sizes for Brazil, China, Guatemala, India, Indonesia, New Zealand, Singapore, the UK, the USA and Zimbabwe. In the model, antivirals stockpiling considerably reduced mortality. There was greater potential avoidance of expected costs in the higher resourced countries (e.g. from $55 billion to $27 billion over a 30 year time horizon for the USA) and large avoidance of fatalities in those less resourced (e.g. from 11.4 to 2.3 million in Indonesia). Under perfect allocation, higher resourced countries should aim to store antiviral stockpiles able to cover at least 15 per cent of their population, rising to 25 per cent with 30 per cent misallocation, to minimize fatalities and economic costs. Stockpiling is estimated not to be cost-effective for two-thirds of the world's population under current antivirals pricing. Lower prices and international cooperation are necessary to make the life-saving potential of antivirals cost-effective in resource-limited countries.
Specific and promiscuous functions of multiple DnaJ proteins in Synechocystis sp. PCC 6803
Authors: Düppre Eva , Rupprecht Eva , Schneider Dirk
Published: February 2011

Cyanobacterial genomes typically encode multiple Hsp70 (DnaK) and Hsp40 (DnaJ) chaperones, and in the genome of the cyanobacteriumSynechocystisPCC 6803, three DnaK proteins are encoded together with seven DnaJ proteins. While only two of the DnaJ proteins can complement the growth defect of anEscherichia coliΔdnaJstrain, only disruption of thednaJgenesll0897resulted in a growth defect at elevated temperatures. Based on the domain structure and the phenotype observed following disruption of the encoding gene, Sll0897 can be classified as a canonical heat-shock protein inSynechocystis. Furthermore, mostdnaJgenes could be deleted individually, whereas disruption of the gene encoding the DnaJ Sll1933 failed, which suggests an essential, yet undefined, function for Sll1933. Since after deletion of the remainingdnaJgenes the phenotypes were not altered, the functions of these DnaJs either are not critical or are taken over by the remaining DnaJs. Nevertheless, only the twodnaJgenessll0909andsll1384could be disrupted in combination, suggesting physiological functions for the two encoded proteins which either are not overlapping and/or can be fulfilled by the remaining DnaJs in the double-disruption strain. Taken together, the present analysis indicates specific and promiscuous functions for multiple DnaJ proteins inSynechocystis.
Deletion of the mmpL4b gene in the Mycobacterium abscessus glycopeptidolipid biosynthetic pathway results in loss of surface colonization capability, but enhanced ability to replicate in human macrophages and stimulate their innate immune response
Authors: Nessar Rachid , Reyrat Jean-Marc , Davidson Lisa B. , Byrd Thomas F.
Published: February 2011

Mycobacterium abscessusis considered to be the most virulent of the rapidly growing mycobacteria. Generation of bacterial gene knockout mutants has been a useful tool for studying factors that contribute to virulence of pathogenic bacteria. Until recently, the optimal genetic approach to generation ofM. abscessusgene knockout mutants was not clear. Based on the recent identification of genetic recombineering as the preferred approach, aM. abscessusmutant was generated in which the genemmpL4b, critical to glycopeptidolipid synthesis, was deleted. Compared to the previously well-characterized parental strain 390S, themmpL4Bdeletion mutant had lost sliding motility and the ability to form biofilm, but acquired the ability to replicate in human macrophages and stimulate macrophage Toll-like receptor 2. This study demonstrates that deletion of a gene associated with expression of a cell-wall lipid can result in acquisition of an immunostimulatory, invasive bacterial phenotype and has important implications for the study ofM. abscessuspathogenesis at the cellular level.