bluuebunny/crossref_metadata_2025 huggingface dataset:
Crustal structure of the Yakutat terrane and the evolution of subduction and collision in southern Alaska
Authors: Worthington Lindsay L. , Van Avendonk Harm J. A. , Gulick Sean P. S. , Christeson Gail L. , Pavlis Terry L.
Published: November 2011

We present a two‐dimensional velocity model to constrain crustal thickness and composition of the Yakutat terrane in the northern Gulf of Alaska. The model was constructed using seismic reflection and refraction data along a ∼455 km onshore‐offshore profile. Our model shows that the crystalline crust composing the Yakutat terrane is wedge‐shaped, with crustal thickness increasing west to east from ∼15 km to ∼30 km. Crustal velocity and structure are continuous across the terrane, with lower crustal velocities >7 km/s, suggesting that the Yakutat terrane is an oceanic plateau across its entire offshore extent rather than a composite oceanic‐continental terrane as previously proposed. The thickest Yakutat crust is entering the adjacent St. Elias orogen where elevated exhumation rates and concentrated seismicity in this vicinity are likely influenced by incipient Yakutat‐North America collision. Our model includes a ∼8 km thick low‐velocity crustal cap extending across the eastern portion of the profile where shallow basement is imaged on marine seismic reflection data. We interpret this cap as a lithified, metamorphosed remnant accretionary prism, providing evidence of a previous attempt at Yakutat subduction along its eastern margin prior to current emplacement at the southern Alaska margin.
Drake Antarctic Agile Meteor Radar first results: Configuration and comparison of mean and tidal wind and gravity wave momentum flux measurements with Southern Argentina Agile Meteor Radar
Authors: Fritts D. C. , Janches D. , Iimura H. , Hocking W. K. , Bageston J. V. , Leme N. M. P.
Published: November 2011

A new generation meteor radar was installed at the Brazilian Antarctic Comandante Ferraz Base (62.1°S) in March 2010. This paper describes the motivations for the radar location, its measurement capabilities, and comparisons of measured mean winds, tides, and gravity wave momentum fluxes from April to June of 2010 and 2011 with those by a similar radar on Tierra del Fuego (53.8°S). Motivations for the radars include the “hotspot” of small‐scale gravity wave activity extending from the troposphere into the mesosphere and lower thermosphere (MLT) centered over the Drake Passage, the maximum of the semidiurnal tide at these latitudes, and the lack of other MLT wind measurements in this latitude band. Mean winds are seen to be strongly modulated at planetary wave and longer periods and to exhibit strong coherence over the two radars at shorter time scales as well as systematic seasonal variations. The semidiurnal tide contributes most to the large‐scale winds over both radars, with maximum tidal amplitudes during May and maxima at the highest altitudes varying from ∼20 to >70 ms−1. In contrast, the diurnal tide and various planetary waves achieve maximum winds of ∼10 to 20 ms−1. Monthly mean gravity wave momentum fluxes appear to reflect the occurrence of significant sources at lower altitudes, with relatively small zonal fluxes over both radars, but with significant, and opposite, meridional momentum fluxes below ∼85 km. These suggest gravity waves propagating away from the Drake Passage at both sites, and may indicate an important source region accounting in part for this “hotspot.”
Advances in upscaling of eddy covariance measurements of carbon and water fluxes
Authors: Xiao Jingfeng , Chen Jiquan , Davis Kenneth J. , Reichstein Markus
Published: November 2011

Eddy covariance flux towers provide continuous measurements of ecosystem‐level net exchange of carbon, water, energy, and other trace gases between land surface and the atmosphere. The upscaling of flux observations from towers to broad regions provides a new and independent approach for quantifying these fluxes over regions, continents, or the globe. The seven contributions of this special section reflect the most recent advances in the upscaling of fluxes from towers to these broad regions. The section mainly stems from presentations at the recent North American Carbon Program (NACP), FLUXNET, and AGU meetings. These studies focus on different aspects of upscaling: (1) assessing the representativeness of flux networks; (2) upscaling fluxes from towers to broad spatial scales; (3) examining the magnitude, distribution, and interannual variability of fluxes over regions, continents, or the globe; and (4) evaluating the impacts of spatial heterogeneity and parameter variability on flux estimates. Collectively, this special issue provides a timely update on upscaling science and also generates gridded flux data that can be used for model evaluations. Future upscaling studies are expected to advance toward incorporating the impacts of disturbance on ecosystem carbon dynamics, quantifying uncertainties associated with gridded flux estimates, and comparing various upscaling methods and the resulting gridded flux fields.
Contrasting recombination patterns and demographic histories of the plant pathogen Ralstonia solanacearum inferred from MLSA
Authors: Wicker Emmanuel , Lefeuvre Pierre , de Cambiaire Jean-Charles , Lemaire Christophe , Poussier Stéphane , Prior Philippe
Published: November 2011

We used multilocus sequence analysis (MLSA) on a worldwide collection of the plant pathogenic Ralstonia solanacearum (Betaproteobacteria) to retrace its complex evolutionary history. Using genetic imprints left during R. solanacearum evolution, we were able to delineate distinct evolutionary complex displaying contrasting dynamics. Among the phylotypes already described (I, IIA, IIB, III, IV), eight groups of strains with distinct evolutionary patterns, named clades, were identified. From our recombination analysis, we identified 21 recombination events that occurred within and across these lineages. Although appearing the most divergent and ancestral phylotype, phylotype IV was inferred as a gene donor for the majority of the recombination events that we detected. Whereas this phylotype apparently fuelled the species diversity, ongoing diversification was mainly detected within phylotype I, IIA and III. These three groups presented a recent expanding population structure, a high level of homologous recombination and evidences of long-distance migrations. Factors such as adaptation to a specific host or intense trading of infected crops may have promoted this diversification. Whether R. solanacearum lineages will eventually evolve in distinct species remains an open question. The intensification of cropping and increase of geographical dispersion may favour situations of phylotype sympatry and promote higher exchange of key factors for host adaptation from their common genetic pool.
ANN Based Virtual Classification Model for Discriminating Active and Inactive Withanolide E Analogs against Human Breast Cancer Cell Line MCF-7
Authors: Prakash Om , Khan Feroz , Sangwan R.S.
Published: November 2011

Withanolides are a group of natural C-28 steroids built on an ergostane skeleton and classified into two major groups according to their structural skeleton: (a) compounds with a beta-oriented side chain and (b) compounds with an alpha-oriented side chain. Withanolide E represents one of the members of the latter group. Classification of active compounds on the basis of pharmacophore against specific cancer cell line poses a serious concern at the primary stage of virtual screening. To overcome this problem we have developed an artificial neural network based virtual screening model for discriminating active and non-active Withanolide-E-like derivatives or analogs against human breast cancer cell line MCF-7. In the present work, a 2D chemical descriptors ensemble pharmacophore has been modelled on the basis of withanolide E structural featured molecules. The ANN structure activity based classification model could be useful for identification of active withanolide analogs as anticancer leads against MCF-7. This model can be used for predicting possible growth inhibitory concentration (logGI50) against breast cancer cell line MCF-7. The virtual screening tool “CanWithaANN” can be accessed at local network of CIMAP.
A New Method for Body Fat Evaluation, Body Adiposity Index, Is Useful in Women With Familial Partial Lipodystrophy
Authors: Godoy‐Matos Amélio F. , Moreira Rodrigo O. , Valerio Cynthia M. , Mory Patricia B. , Moises Regina S.
Published: November 2011

BMI is a widely used method to evaluate adiposity. However, it has several limitations, particularly an inability to differentiate lean from fat mass. A new method, body adiposity index (BAI), has been recently proposed as a new measurement capable to determine fat excess better than BMI. The aim of this study was to investigate BAI as a mean to evaluate adiposity in a group of women with familial partial lipodystrophy (FPLD) and compare it with BMI. Thirteen women with FLPD Dunnigan type (FPLD2) and 13 healthy volunteers matched by age and BMI were studied. Body fat content and distribution were analyzed by dual X‐ray absorptiometry (DXA). Plasma leptin was also measured. BAI was significantly lower in FPLD2 in comparison to control group (24.6 ± 1.5 vs. 30.4 ± 4.3; P < 0.001) and presented a more significant correlation with total fat (%) (r = 0.71; P < 0.001) and fat Mass (g) (r = 0.80; P < 0.001) than BMI (r = 0.27; P = 0.17 for total fat and r = 0.52; P = 0.006 for fat mass). There was a correlation between leptin and BAI (r = −0.54; P = 0.004), but not between leptin and BMI. In conclusion, BAI was able to catch differences in adiposity in a sample of FPLD2 patients. It also correlated better with leptin levels than BMI. Therefore, we provide further evidence that BAI may become a more reliable indicator of fat mass content than the currently available measurements.
Concordance of the Recently Published Body Adiposity Index With Measured Body Fat Percent in European‐American Adults
Authors: Johnson William , Chumlea William C. , Czerwinski Stefan A. , Demerath Ellen W.
Published: November 2011

The body adiposity index (BAI; hip circumference (cm)/height (m)1.5 − 18) has recently been shown to demonstrate a stronger correlation with percentage body fat (%fat) than that between the BMI and %fat in Mexican‐American adults. Here, we compare the concordance between %fat from dual‐energy X‐ray absorptiometry (DXA) and BAI, and between %fat and BMI, in European‐American adults (n = 623). Agreement between BAI, BMI, and %fat was assessed using Lin's concordance coefficients (ρc), where values <0.90 are considered poor. In the sample as a whole, the agreement between BAI and %fat (ρc = 0.752) was far better than that between BMI and %fat (ρc = 0.445) but was nonetheless relatively poor. There were large mean differences in %fat between the BAI and DXA %fat, particularly at lower levels of adiposity (<20%), and further the BAI overestimated %fat in males and underestimated %fat in females. Optimizing the BAI formula for our sample only marginally improved performance. Results of the present study show that BAI provides a better indicator of adiposity in European‐American adults than does BMI, but does not provide valid estimates of %fat, particularly at lower levels of body fatness. Further research is warranted to investigate the predictive ability of BAI for various health outcomes.
Factors limiting the open-circuit voltage in microcrystalline silicon solar cells
Authors: Nath M. , Chakraborty S. , Johnson E.V. , Abramov A. , Roca i Cabarrocas P. , Chatterjee P.
Published: November 2011

In studying photovoltaic devices made with silicon thin films and considering them according to their grain size, it is curious that as the crystalline fraction increases, the open-circuit voltage (Voc) – rather than approaching that of the single-crystal case – shows a decline. To gain an insight into this behavior, observed in hydrogenated microcrystalline silicon (μc-Si:H) solar cells prepared under a variety of deposition conditions, we have used a detailed electrical-optical computer modeling program, ASDMP. Two typical μc-Si:H cells with low (~79%) and higher (~93%) crystalline volume fractions (Fc), deposited in our laboratory and showing this general trend, were modeled. From the parameters extracted by simulation of their experimental current density – voltage and quantum efficiency characteristics, it was inferred that the higher Fc cell has both a higher band gap defect density as well as a lower band gap energy. Our calculations reveal that the proximity of the quasi-Fermi levels to the energy bands in cells based on highly crystallized μc-Si:H (assumed to have a lower band gap), results in both higher free and trapped carrier densities. The trapped hole population, that is particularly high near the P/I interface, results in a strong interface field, a collapse of the field in the volume, and hence a lower open-circuit voltage. Interestingly enough, we were able to fabricate fluorinated μc-Si:H:F cells having 100% crystalline fraction as well as very large grains, that violate the general trend and show a higher Voc. Modeling indicates that this is possible for the latter case, as also for a crystalline silicon PN cell, in spite of a sharply reduced band gap, because the lower effective density of states at the band edges and a sharply reduced gap defect density overcome the effect of the lower band gap.
Shift of isoelectric point in extended nanospace investigated by streaming current measurement
Authors: Morikawa Kyojiro , Mawatari Kazuma , Kazoe Yutaka , Tsukahara Takehiko , Kitamori Takehiko
Published: November 2011

Isoelectric points in extended nanochannels (580-2720 nm) fabricated on fused-silica substrates were measured using the streaming current method. The isoelectric point obtained in a 2720 nm channel was almost the same as the isoelectric point reported for the bulk (2.6-3.2). However, the isoelectric point in the extended nanochannel (580 nm) was decreased to less than 2.0. This result provides important information for the modeling of ion transport in extended nanospace.
Thermodynamic limit to photonic-plasmonic light-trapping in thin films on metals
Authors: Schiff E. A.
Published: November 2011

We calculate the maximum optical absorptance enhancements in thin semiconductor films on metals due to structures that diffuse light and couple it to surface plasmon polaritons. The calculations can be used to estimate plasmonic effects on light-trapping in solar cells. The calculations are based on the statistical distribution of energy in the electromagnetic modes of the structure, which include surface plasmon polariton modes at the metal interface as well as the trapped waveguide modes in the film. The enhancement has the form 4n2+nλ/h (n – film refractive index, λ – optical wavelength, h – film thickness), which is an increase beyond the non-plasmonic “classical” enhancement 4n2. Larger resonant enhancements occur for wavelengths near the surface plasmon frequency; these add up to 2 mA/cm2 to the photocurrent of a solar cell based on a 500 nm film of crystalline silicon. We also calculated the effects of plasmon dissipation in the metal. Dissipation rates typical of silver reverse the resonant enhancement effect for silicon, but a non-resonant enhancement remains.
Euclidean Jordan algebras, hidden actions, and J-Kepler problems
Authors: Meng Guowu
Published: November 2011

For a simple euclidean Jordan algebra, let $\mathfrak {co}$co be its conformal algebra, $\mathscr P$P be the manifold consisting of its semi-positive rank-one elements, $C^\infty (\mathscr P)$C∞(P) be the space of complex-valued smooth functions on $\mathscr P$P. An explicit action of $\mathfrak {co}$co on $C^\infty (\mathscr P)$C∞(P), referred to as the hidden action of $\mathfrak {co}$co on $\mathscr P$P, is exhibited. This hidden action turns out to be mathematically responsible for the existence of the Kepler problem and its recently discovered vast generalizations, referred to as J-Kepler problems. The J-Kepler problems are then reconstructed and re-examined in terms of the unified language of euclidean Jordan algebras. As a result, for a simple euclidean Jordan algebra, the minimal representation of its conformal group can be realized either as the Hilbert space of bound states for its J-Kepler problem or as $L^2({\mathscr P}, {1\over r}\mathrm{vol})$L2(P,1r vol ), where vol is the volume form on $\mathscr P$P and r is the inner product of $x\in \mathscr P$x∈P with the identity element of the Jordan algebra.
Experimental verification of photon angular momentum and vorticity with radio techniques
Authors: Tamburini Fabrizio , Mari Elettra , Thidé Bo , Barbieri Cesare , Romanato Filippo
Published: November 2011

The experimental evidence that radio techniques can be used for synthesizing and analyzing non-integer electromagnetic (EM) orbital angular momentum (OAM) of radiation is presented. The technique used amounts to sample, in space and time, the EM field vectors and digitally processing the data to calculate the vortex structure, the spatial phase distribution, and the OAM spectrum of the radiation. The experimental verification that OAM-carrying beams can be readily generated and exploited by using radio techniques paves the way to an entirely new paradigm of radar and radio communication protocols.
Mechanical properties of rare earth stannate pyrochlores
Authors: Feng J. , Xiao B. , Qu Z. X. , Zhou R. , Pan W.
Published: November 2011

The RE2Sn2O7 series compounds (RE = La, Nb, Sm, Gd, Er, Yb) with a pyrochlore structure are prepared by co-precipitation method. The bulk, shear, Young’s moduli, B/G, and Poisson’s ratios are calculated using density functional theory and also measured by ultrasonic resonance method. The theoretical values of lattice constants and mechanical moduli are smaller than experimental results. The electronic structures of RE2Sn2O7 are analogous to RE2Zr2O7. La2Sn2O7 exhibits stronger ionic bonds than others. The covalent interactions are slightly enhanced in the heavy rare earth stannate pyrochlores. The Vickers harnesses of RE2Sn2O7 are measured experimentally, which are smaller than theoretical predictions.
Magnetic curves corresponding to Killing magnetic fields in ${\mathbb {E}}^3$E3
Authors: Druţă-Romaniuc Simona Luiza , Munteanu Marian Ioan
Published: November 2011

We explicitly determine all magnetic curves corresponding to the Killing magnetic fields on the 3-dimensional Euclidean space.
Simulations of granular bed erosion due to laminar shear flow near the critical Shields number
Authors: Derksen J. J.
Published: November 2011

Direct numerical simulations of granular beds consisting of uniformly sized spherical particles being eroded by a shear flow of Newtonian liquid have been performed. The lattice-Boltzmann method has been used for resolving the flow of the interstitial liquid. Fluid and solid dynamics are fully coupled with the particles having finite size and undergoing hard-sphere collisions. Only laminar flow has been considered with particle-based Reynolds numbers in the range 0.02 to 0.6. The parameter range of the simulations covers the transition between static and mobilized beds. The transition occurs for 0.10<θ<0.15 with θ the Shields number. The transition is insensitive of the Reynolds number and the solid-over-liquid density ratio. Incipient bed motion has been interpreted in terms of the probability density functions of the hydrodynamic forces acting on the spheres in the upper layer of the bed.
Investigation of dielectric and electrical properties of Mn doped sodium potassium niobate ceramic system using impedance spectroscopy
Authors: Rani Rashmi , Sharma Seema , Rai Radheshyam , Kholkin Andrei L.
Published: November 2011

A single perovskite phase formation of polycrystalline samples of (Na0.52K0.44Li0.04) (Nb0.86-xTa0.1Sb0.04Mnx) (where x = 0.00, 0.01, 0.03, and 0.05) here by denoted as NKNLST and Mn doped NKNLST were prepared by mixed oxide method. The preliminary structural studies were carried out by x-ray diffraction technique showing the formation of single perovskite phase with orthorhombic symmetry for all compositions. Addition of Mn in NKNLST system lowered the sintering temperature by 75 °C. Detail study of impedance parameters shows the non-Debye temperature of relaxation phenomena in the system. This analysis enables us to separate grain and grain boundary contribution of the materials. Above the ferroelectric–paraelectric phase transition temperature, the electrical conduction is governed by the thermal excitation of carriers from oxygen vacancies exhibiting Negative temperature coefficient (NTCR) behaviour.
Renormalization group transformations near the critical point: Some rigorous results
Authors: Yin Mei
Published: November 2011

We consider renormalization group (RG) transformations for classical Ising-type lattice spin systems in the infinite-volume limit. Formally, the RG maps a Hamiltonian H into a renormalized Hamiltonian H′, \documentclass[12pt]{minimal}\begin{document}$\exp (-H^{\prime }(\sigma ^{\prime }))=\sum _{\sigma }T(\sigma , \sigma ^{\prime })\break\exp (-H(\sigma )),$\end{document}exp(−H′(σ′))=∑σT(σ,σ′)exp(−H(σ)), where T(σ, σ′) denotes a specific RG probability kernel, \documentclass[12pt]{minimal}\begin{document}$\sum _{\sigma ^{\prime }}T(\sigma , \sigma ^{\prime })=1$\end{document}∑σ′T(σ,σ′)=1, for every configuration σ. With the help of the Dobrushin uniqueness condition and standard results on the polymer expansion, Haller and Kennedy gave a sufficient condition for the existence of the renormalized Hamiltonian in a neighborhood of the critical point. By a more complicated but reasonably straightforward application of the cluster expansion machinery, the present investigation shows that their condition would further imply a band structure on the matrix of partial derivatives of the renormalized interaction with respect to the original interaction. This in turn gives an upper bound for the RG linearization.
Resonant x-ray reflectivity study of perovskite oxide superlattices
Authors: Kemik N. , Gu M. , Yang F. , Chang C.-Y. , Song Y. , Bibee M. , Mehta A. , Biegalski M. D. , Christen H. M. , Browning N. D. , Takamura Y.
Published: November 2011

Resonant x-ray reflectivity (XRR) is utilized to characterize the structural properties of La0.7Sr0.3MnO3/La0.7Sr0.3FeO3 superlattices. XRR spectra at the Mn and Fe absorption edges provide additional structural information compared to spectra obtained with a conventional Cu x-ray source. We demonstrate that this technique provides individual layer thicknesses and intermixing behavior of perovskite superlattices with small density contrast in a non-destructive manner. These results are consistent with scanning transmission electron microscopy and electron energy loss spectroscopy.
A novel approach for high precision rapid potentiometric titrations: Application to hydrazine assay
Authors: Sahoo P. , Malathi N. , Ananthanarayanan R. , Praveen K. , Murali N.
Published: November 2011

We propose a high precision rapid personal computer (PC) based potentiometric titration technique using a specially designed mini-cell to carry out redox titrations for assay of chemicals in quality control laboratories attached to industrial, R&D, and nuclear establishments. Using this technique a few microlitre of sample (50–100 μl) in a total volume of ∼2 ml solution can be titrated and the waste generated after titration is extremely low comparing to that obtained from the conventional titration technique. The entire titration including online data acquisition followed by immediate offline analysis of data to get information about concentration of unknown sample is completed within a couple of minutes (about 2 min). This facility has been created using a new class of sensors, viz., pulsating sensors developed in-house. The basic concept in designing such instrument and the salient features of the titration device are presented in this paper. The performance of the titration facility was examined by conducting some of the high resolution redox titrations using dilute solutions-–hydrazine against KIO3 in HCl medium, Fe(II) against Ce(IV) and uranium using Davies–Gray method. The precision of titrations using this innovative approach lies between 0.048% and 1.0% relative standard deviation in different redox titrations. With the evolution of this rapid PC based titrator it was possible to develop a simple but high precision potentiometric titration technique for quick determination of hydrazine in nuclear fuel dissolver solution in the context of reprocessing of spent nuclear fuel in fast breeder reactors.
Sensory and short-term memory formations observed in a Ag2S gap-type atomic switch
Authors: Ohno Takeo , Hasegawa Tsuyoshi , Nayak Alpana , Tsuruoka Tohru , Gimzewski James K. , Aono Masakazu
Published: November 2011

Memorization caused by the change in conductance in a Ag2S gap-type atomic switch was investigated as a function of the amplitude and width of input voltage pulses (Vin). The conductance changed little for the first few Vin, but the information of the input was stored as a redistribution of Ag-ions in the Ag2S, indicating the formation of sensory memory. After a certain number of Vin, the conductance increased abruptly followed by a gradual decrease, indicating the formation of short-term memory (STM). We found that the probability of STM formation depends strongly on the amplitude and width of Vin, which resembles the learning behavior of the human brain.
Impurity impact ionization avalanche in p-type diamond
Authors: Mortet V. , Soltani A.
Published: November 2011

Electrical conductivity of a highly boron doped chemical vapor deposited diamond thin film has been studied at different temperatures under high electric field conditions. Current-voltage characteristics have been measured using pulsed technique to reduce thermal effects. Experimental results evidence deep impurity impact ionization avalanche in p-type diamond up to room temperature.
High quality crystalline silicon surface passivation by combined intrinsic and n-type hydrogenated amorphous silicon
Authors: Schüttauf Jan-Willem A. , van der Werf Karine H. M. , Kielen Inge M. , van Sark Wilfried G. J. H. M. , Rath Jatindra K. , Schropp Ruud E. I.
Published: November 2011

We investigate the influence of thermal annealing on the passivation quality of crystalline silicon (c-Si) surfaces by intrinsic and n-type hydrogenated amorphous silicon (a-Si:H) films. For temperatures up to 255 °C, we find an increase in surface passivation quality, corresponding to a decreased dangling bond density. Due to the combined chemical and field effect passivation of the intrinsic/n-type a-Si:H layer stack, we obtained minority carrier lifetimes with a value as high as 13.3 ms at an injection level of 1015 cm−3. For higher annealing temperatures, a decreased passivation quality is observed, which is attributed to hydrogen effusion.
Self-biased converse magnetoelectric effect
Authors: Chul Yang Su , Cho Kyung-Hoon , Park Chee-Sung , Priya Shashank
Published: November 2011

In this letter, we investigate the direct magnetoelectric (DME) and converse magnetoelectric (CME) effects in three-phase metal–ceramic laminate composites. Longitudinally poled and transversely magnetized (L-T) laminate was fabricated by bonding nickel plates between the two particulate magnetoelectric (ME) composite layers of composition 0.8 (0.948 K0.5Na0.5NbO3 – 0.052 LiSbO3) – 0.2 (Ni0.8Zn0.2Fe2O4) (KNNLS-NZF). Under off-resonance condition, the laminates exhibited hysteretic DME and CME responses as a function of applied bias field (Hbias). Self-biased effect characterized by non-zero ME response at zero Hbias was observed. The self-biased DME and CME properties were found to be enhanced under resonance conditions. Without external Hbias, magnetic induction switching was possible by applying AC voltage. These results provide the possibility of using self-biased CME effect in electrically controlled memory devices and magnetic flux control devices.
Photoemission induced bias in two-dimensional silicon pn junctions
Authors: Lavayssière M. , Renault O. , Mariolle D. , Veillerot M. , Barnes J. P. , Hartmann J. M. , Leroy J. , Barrett N.
Published: November 2011

Spectroscopic x-ray photoelectron emission microscopy was used to study the role of the pn junction on imaging of micron scale n- and p-doped silicon patterns epitaxially grown on p- and n-type substrates, respectively. In the closed n-doped patterns, contrast with respect to open patterns is observed in both work function and Si 2p binding energy. Reverse bias at the junction creates a shift of electrical potential induced by photoemission in the closed patterns. No shift is observed for p-doped patterns on n substrate, pointing to the importance of doping combination and pattern geometry in the contrast observed in electron microscopy.
Effect of different levels of amino acids on carcass composition and yield in broilers
Authors: Nasr Javad
Published: November 2011

An experiment was conducted to evaluate the carcass yield and composition of 200 Arian male broilers fed diets (starter and grower) with different levels of amino acids requirements (high, medium, standard and low amino acids) in a completely randomised experimental design. All diets were isocaloric and isonitrogenous. Increased proportion of breast and thigh to bodyweight ratio were also obtained by increasing the level of amino acids from standard to high amino acids at 42 days of age (P < 0.05). In broilers receiving 120% of National Research Council amino acids, bodyweight at 42 days of age increased significantly by 202 g compared with standard amino acids diet. Feeding broilers with a high amino acid diet significantly (P < 0.05) increased carcass, breast, thigh and abdominal fat weights compared with standard group. Treatment with high amino acids had significantly higher levels of crude protein, lysine, and methionine percentage of breast and thigh meat in Arian broilers. The results of this study suggest that additional amino acids in starter and grower diets optimised bodyweight gain in Arian broiler, whereas reductions in amino acid levels reduced growth and liveweight.
Acidification increases mercury uptake by a freshwater alga, Chlamydomonas reinhardtii
Authors: Le Faucheur Séverine , Tremblay Yvan , Fortin Claude , Campbell Peter G. C.
Published: November 2011

Environmental contextMercury is classified as a priority pollutant owing to the biomagnification of its methylated species along food chains and the consequent effects on top consumers. The pH of natural waters affects many of the biogeochemical processes that control mercury accumulation in aquatic organisms. Here, evidence is presented that pH affects mercury uptake by unicellular algae, primary producers in aquatic food chains, thereby providing a new example of the pervasive influence of pH on the mercury biogeochemical cycle.
AbstractWe have examined the influence of pH on HgII uptake (mainly in the form of the lipophilic complex HgCl2) by a green, unicellular alga, Chlamydomonas reinhardtii. Uptake of the dichloro complex increased by a factor of 1.6 to 2 when the pH was lowered from 6.5 to 5.5, an unexpected result given that the intracellular hydrolysis rate of fluorescein diacetate (FDA), used as a probe for the passive diffusion of lipophilic solutes through algal membranes, decreased in the studied alga under similar conditions. Several mechanisms were explored to explain the enhanced uptake at pH 5.5, including pH-induced changes in cell surface binding of Hg or in Hg loss rates from cells, but none of them gave completely satisfactory explanations. The present findings imply that inorganic HgII in aqueous solution behaves, in terms of uptake, neither as a lipophilic complex (the uptake of which would be expected to decrease with acidification because of algal membrane packing), nor as a cationic metal (the transport of which by facilitated transport would be expected to diminish with increasing proton concentration because of metal–proton competition at the transporter binding sites). Mercury uptake by algae seems rather to be stimulated by proton addition.
Private health insurance and quality of life: perspectives of older Australians with multiple chronic conditions
Authors: Jeon Yun-Hee , Black Annie , Govett Janelle , Yen Laurann , McRae Ian
Published: November 2011

A qualitative study was conducted to explore in-depth issues relating to the health costs of chronic illness as identified in a previous study. A key theme that emerged from interviews carried out was the benefits and challenges of private health insurance (PHI) membership, and choices older Australians with multimorbidity make in accessing health services, with and without PHI. This is the focus of this paper. Semistructured interviews were conducted with 40 older people with multiple chronic conditions. Data were analysed using content analysis. Key motivators for maintaining PHI included: fear of an inability to access timely health care; the opportunity to exercise choice in service provider; a belief of being ‘better off’ both medically and financially, which was often ill-founded; and the core values of self reliance and independence. Most described financial pressure caused by rising PHI premiums as well as other out-of-pocket health related expenses. Many older people who can ill afford PHI still struggle to maintain it, potentially at the cost of their quality of life, based on beliefs about costs of health care that they have never properly assessed. The findings highlight the degree to which people whose resources are constrained are prepared to go to maintain access to private hospital care. Attention should be given to assisting older people to make informed and valid choices of health insurance derived from the facts, rather than being based on fear and assumptions.
Could zinc prevent reproductive alterations caused by cigarette smoke in male rats?
Authors: Garcia Patrícia Carvalho , Piffer Renata Carolina , Gerardin Daniela Cristina Cecatto , Sankako Michele Kimie , Alves de Lima Rodrigo Otávio , Pereira Oduvaldo Câmara Marques
Published: November 2011

The aim of the present study was to evaluate the effects of zinc on fertility through semen parameters, testosterone level and oxidative DNA damage to spermatozoa of rats exposed to cigarette smoke. Male Wistar rats (60 days old) were divided into four groups (n = 10 per group): control, cigarette-smoking (20 cigarettes per day), zinc (zinc chloride 20 mg kg–1 day–1) and zinc plus cigarette-smoking (zinc chloride 20 mg kg–1 day–1; 20 cigarettes per day). The treatment was applied for nine weeks and the following parameters were analysed: bodyweight, wet weights of the reproductive organs and the adrenal gland, plasma testosterone concentration, testicular function (seminal analysis and daily sperm production) and sperm DNA oxidative damage. The exposure to cigarette smoke decreased testosterone concentration, the percentage of normal morphology and the motility of spermatozoa. In addition, this exposure increased sperm DNA oxidative damage. Zinc treatment protected against the toxic damage that smoking caused to spermatozoa. This study showed a correlation between smoking and possible male infertility and subfertility, and also that the majority of smoking-induced changes in spermatozoa were prevented by zinc treatment. In conclusion, zinc, an antioxidant and stimulant of cell division, can be indicated as a promising treatment in men with infertility caused by the toxic components of cigarette smoke.
Application of an integrated multidisciplinary economic welfare approach to improved wellbeing through Aboriginal caring for country
Authors: Campbell David
Published: November 2011

The lands held by Aboriginal people are mostly located in the Australian desert, aside from pastoral country purchased under the Indigenous Land Corporation, they are among the least amenable to agricultural production. Social expectations regarding land use are undergoing a multifunctional transition with a move away from a focus on production, to increased amenity and conservation uses. This change means that Aboriginal people with cultural connections to country enjoy an absolute advantage in managing country through their application of land care involving Indigenous ecological knowledge. An integrated multidisciplinary economic welfare approach, based on data from northern Australia and the central Australian desert, is used to demonstrate the role Aboriginal people can play in caring for country. Such engagement can be to the advantage of Aboriginal people through a multiplicity of private and public good benefits, such as improving Aboriginal health, maintaining biodiversity, and the mitigation of climate change impacts through possible greenhouse gas biosequestration and the reduction of dust storms – which are an important vector of disease.
Cadmium-induced changes in soil biochemical characteristics of oat (Avena sativa L.) rhizosphere during early growth stages
Authors: Astolfi Stefania , Zuchi Sabrina , De Cesare Fabrizio , Badalucco Luigi , Grego Stefano
Published: November 2011

A microcosm was assembled to physically separate soil from roots and was used to study both the impact of living roots on the soil–plant system during early stages of growth and plant responses to abiotic stress. Oat (Avena sativa L.) seedlings were grown in the microcosm unit for 44 days. Twenty-three days after planting, 0.154 mg CdSO4/g dry soil was added. Plants grown in Cd-treated microcosms showed considerable inhibition of shoot growth rates, and leaf chlorophyll content. Soil microbial biomass C and respiration increased with plant age, and most of the measured biochemical indicators decreased with increasing distance from the soil–root interface, thus demonstrating the rhizosphere effect, likely due to the quick assimilation of rhizodeposits by rhizosphere microflora. On the other hand, short-term Cd contamination sometimes had an inhibitory effect on soil respiration, qCO2, ATP content, and phosphatase activity, while stimulating microbial biomass, mainly at the rhizosphere level. The decrease in rhizosphere microbial activity observed after Cd application to soil may be due to a synergic effect of the metal directly on microbial cells and indirectly on plants, which reduced shoot growth rate and chlorophyll content, resulting in decreased availability of root exudates.
Microbial methane production in oxygenated water column of an oligotrophic lake
Authors: Grossart Hans-Peter , Frindte Katharina , Dziallas Claudia , Eckert Werner , Tang Kam W.
Published: November 2011

The prevailing paradigm in aquatic science is that microbial methanogenesis happens primarily in anoxic environments. Here, we used multiple complementary approaches to show that microbial methane production could and did occur in the well-oxygenated water column of an oligotrophic lake (Lake Stechlin, Germany). Oversaturation of methane was repeatedly recorded in the well-oxygenated upper 10 m of the water column, and the methane maxima coincided with oxygen oversaturation at 6 m. Laboratory incubations of unamended epilimnetic lake water and inoculations of photoautotrophs with a lake-enrichment culture both led to methane production even in the presence of oxygen, and the production was not affected by the addition of inorganic phosphate or methylated compounds. Methane production was also detected by in-lake incubations of lake water, and the highest production rate was 1.8–2.4 nM⋅h
−1
at 6 m, which could explain 33–44% of the observed ambient methane accumulation in the same month. Temporal and spatial uncoupling between methanogenesis and methanotrophy was supported by field and laboratory measurements, which also helped explain the oversaturation of methane in the upper water column. Potentially methanogenic Archaea were detected in situ in the oxygenated, methane-rich epilimnion, and their attachment to photoautotrophs might allow for anaerobic growth and direct transfer of substrates for methane production. Specific PCR on mRNA of the
methyl coenzyme M reductase A
gene revealed active methanogenesis. Microbial methane production in oxygenated water represents a hitherto overlooked source of methane and can be important for carbon cycling in the aquatic environments and water to air methane flux.
The Reproductive Biology of Siscowet and Lean Lake Trout in Southern Lake Superior
Authors: Goetz Frederick , Sitar Shawn , Rosauer Daniel , Swanson Penny , Bronte Charles R. , Dickey Jon , Simchick Crystal
Published: November 2011

Lean and siscowet morphotypes of lake trout Salvelinus namaycush in Lake Superior are thought to be genetically separate, but the reproductive isolating mechanism is unknown. The testicular and ovarian cycles and reproductive hormone levels of these morphotypes were determined from May to October in populations east and west of the Keweenaw Peninsula in southern Lake Superior. The gonadosomatic index (GSI) increased from August to October for lean and siscowet males and females east of the Keweenaw Peninsula and for siscowets west of the Keweenaw Peninsula. Circulating estradiol‐17β (E2) levels and ovarian GSIs increased simultaneously in females of both morphotypes. However, circulating 11‐ketotestosterone (11‐KT) levels in lean and siscowet males were not significantly elevated until October even though testicular GSIs increased by August. Transcripts of the follicle stimulating hormone (FSH) beta subunit (an indirect measure of FSH activity) increased in lean and siscowet males and females during August and September, when GSIs were increasing for both morphotypes. The seasonal changes in GSIs and hormone levels indicate that both lean and siscowet individuals in southern Lake Superior populations undergo reproductive maturation at the same time in the fall; therefore, reproductive timing does not appear to genetically isolate the morphotypes in these populations. A proportion of the sampled females (lean lake trout: 54%; siscowets: 42%) exhibited no increase in GSI from August to October, strongly suggesting that in any given year some proportion of the population does not reproduce. This was also observed in males but at a lower percentage (19–20%). Fish that did not have maturing gonads from August to October also had lower E2 and 11‐KT levels than maturing fish. Fecundity measured for lean and siscowet lake trout was not statistically different and was similar to historical values.
One hundred years of Yugoslavia: the vision of Stojan Novaković revisited
Authors: Aleksov Bojan
Published: November 2011

This article examines a text written 100 years ago by Stojan Novaković, a leading Serbian scholar and president of its Academy of Science. Written in a political science fiction genre, it foresees a country of united South Slavs in 2011. Yugoslavia, in the enlightened vision of Novaković, will appear and strengthen due to scientific and economic development on one hand and common culture based on a common vernacular on the other. Elite-driven unification is the only mode for South Slavs to survive facing the challenges of modernization and the territorial threats of their neighbors. Accurate in some and grossly naive in other aspects, this text is a testimony of Yugoslav ideas preceding the actual creation of the state, as shared by the most prestigious among the Serbian intellectual elites.
Time-sliced Velocity Map Imaging Study on Photodissociation of Neopentyl Bromide andTert-pentyl Bromide at 234 nm
Authors: Mao Rui , Zhang Qun , Zang Jian-zheng , Zhang Zhi-guo , He Chao , Qin Cheng-bing , Chen Yang
Published: November 2011

We present a first velocity map imaging study on the 234 nm photodissociation dynamics of two carbon-chain branched alkyl bromides, neopentyl bromide (denoted as NPB) and tert-pentyl bromide (denoted as TPB). Unlike the 234 nm photodissociation of the unbranched n-C5H11Br molecule where only a direct fission of the C—Br bond is involved, the branched NPB and TPB molecules exhibit one and two more independent dissociation pathways with much energy being decayed via an extensive excitation of the bending modes of the parent molecules prior to the C—Br bond fission. This observation strongly suggests that the dissociation coordinate for the two carbon-chain branched molecules is no longer solely ascribed to the C—Br stretching mode but rather a combination of the bending-stretching modes.
RNA-related nuclear functions of human Pat1b, the P-body mRNA decay factor
Authors: Marnef Aline , Weil Dominique , Standart Nancy
Published: November 2011

The evolutionarily conserved Pat1 proteins are P-body components recently shown to play important roles in cytoplasmic gene expression control. Using human cell lines, we demonstrate that human Pat1b is a shuttling protein whose nuclear export is mediated via a consensus NES sequence and Crm1, as evidenced by leptomycin B (LMB) treatment. However, not all P-body components are nucleocytoplasmic proteins; rck/p54, Dcp1a, Edc3, Ge-1, and Xrn1 are insensitive to LMB and remain cytoplasmic in its presence. Nuclear Pat1b localizes to PML–associated foci and SC35-containing splicing speckles in a transcription-dependent manner, whereas in the absence of RNA synthesis, Pat1b redistributes to crescent-shaped nucleolar caps. Furthermore, inhibition of splicing by spliceostatin A leads to the reorganization of SC35 speckles, which is closely mirrored by Pat1b, indicating that it may also be involved in splicing processes. Of interest, Pat1b retention in these three nuclear compartments is mediated via distinct regions of the protein. Examination of the nuclear distribution of 4E-T(ransporter), an additional P-body nucleocytoplasmic protein, revealed that 4E-T colocalizes with Pat1b in PML-associated foci but not in nucleolar caps. Taken together, our findings strongly suggest that Pat1b participates in several RNA-related nuclear processes in addition to its multiple regulatory roles in the cytoplasm.
Spindle assembly requires complete disassembly of spindle remnants from the previous cell cycle
Authors: Woodruff Jeffrey B. , Drubin David G. , Barnes Georjana
Published: November 2011

Incomplete mitotic spindle disassembly causes lethality in budding yeast. To determine why spindle disassembly is required for cell viability, we used live-cell microscopy to analyze a double mutant strain containing a conditional mutant and a deletion mutant compromised for the kinesin-8 and anaphase-promoting complex-driven spindle-disassembly pathways (td-kip3 and doc1Δ, respectively). Under nonpermissive conditions, spindles in td-kip3 doc1Δ cells could break apart but could not disassemble completely. These cells could exit mitosis and undergo cell division. However, the daughter cells could not assemble functional, bipolar spindles in the ensuing mitosis. During the formation of these dysfunctional spindles, centrosome duplication and separation, as well as recruitment of key midzone-stabilizing proteins all appeared normal, but microtubule polymerization was nevertheless impaired and these spindles often collapsed. Introduction of free tubulin through episomal expression of α- and β-tubulin or introduction of a brief pulse of the microtubule-depolymerizing drug nocodazole allowed spindle assembly in these td-kip3 doc1Δ mutants. Therefore we propose that spindle disassembly is essential for regeneration of the intracellular pool of assembly-competent tubulin required for efficient spindle assembly during subsequent mitoses of daughter cells.