bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of dietary methionine and white tea on oxidative status of gilthead sea bream (Sparus aurata)
Authors: Pérez-Jiménez Amalia , Peres Helena , Cruz Rubio Vera , Oliva-Teles Aires
Published: December 2011

Free radicals are continuously generated during an organism's lifetime. In order to understand the involvement in the oxidative status of fish, methionine and white tea were assayed as antioxidant supplements in diets for gilthead sea bream (Sparus aurata). For the purpose of this study, four isonitrogenous and isolipidic diets were formulated to contain 45 % of protein and 18 % lipid and 0·3 % methionine (Met diet), 2·9 % white tea dry leaves (Tea diet) and 2·9 % of white tea dry leaves+0·3 % methionine (Tea+Met diet). An unsupplemented diet was used as the control. Key enzymatic antioxidant defences, superoxide dismutase (SOD) isoenzyme profile, total, reduced and oxidised glutathione and oxidative damage markers were determined. The results showed that dietary methionine supplementation increased liver SOD activity, while white tea induced higher hepatic catalase activity. Dietary white tea induced a notable increase in Mn-SOD isoenzyme. This is the first study to provide evidence that dietary tea inclusion in fish feeding could be an important source of Mn with metabolic repercussions on antioxidant mechanisms.
GLOBAL EXISTENCE AND BLOW-UP FOR A DOUBLY DEGENERATE PARABOLIC EQUATION SYSTEM WITH NONLINEAR BOUNDARY CONDITIONS
Authors: MI YONG-SHENG , MU CHUN-LAI , LIU DENG-MING
Published: December 2011

In this paper, we deal with the global existence and blow-up of solutions to a doubly degenerative parabolic system with nonlinear boundary conditions. By constructing various kinds of sub- and super-solutions and using the basic properties of M-matrix, we give the necessary and sufficient conditions for global existence of non-negative solutions, which extend the recent results of Zheng, Song and Jiang (S. N. Zheng, X. F. Song and Z. X. Jiang, Critical Fujita exponents for degenerate parabolic equations coupled via nonlinear boundary flux, J. Math. Anal. Appl. 298 (2004), 308–324), Xiang, Chen and Mu (Z. Y. Xiang, Q. Chen, C. L. Mu, Critical curves for degenerate parabolic equations coupled via nonlinear boundary flux, Appl. Math. Comput. 189 (2007), 549–559) and Zhou and Mu (J. Zhou and C. L Mu, On critical Fujita exponents for degenerate parabolic system coupled via nonlinear boundary flux, Pro. Edinb. Math. Soc. 51 (2008), 785–805) to more general equations.
INDICABLE GROUPS AND ENDOMORPHIC PRESENTATIONS
Authors: BENLI MUSTAFA GÖKHAN
Published: December 2011

In this paper we look at presentations of subgroups of finitely presented groups with infinite cyclic quotients. We prove that if H is a finitely generated normal subgroup of a finitely presented group G with G/H cyclic, then H has ascending finite endomorphic presentation. It follows that any finitely presented indicable group without free semigroups has the structure of a semidirect product H ⋊ ℤ, where H has finite ascending endomorphic presentation.
Cameronia(lichenized Ascomycetes), a remarkable new alpine genus from Tasmania
Authors: KANTVILAS Gintaras
Published: December 2011

The new genus,CameroniaKantvilas, is described and illustrated. It is characterized by a crustose thallus, a chlorococcalean photobiont, deeply immersed perithecioid ascomata, four-spored asci with an intensely hemiamyloid outer wall and non-amyloid, well-developed tholus, and hyaline, muriform ascospores. The taxonomic position of the new genus is uncertain although a relationship with theOstropomycetidaeis likely. Two species, both endemic to the highlands of Tasmania, are described:C. pertusarioidesKantvilas, which is one of the most common lichens on dolerite in alpine Tasmania, andC. tectaKantvilas, which is confined to metamorphosed sediments.
A new Agonimia from Europe with a flabelliform thallus
Authors: GUZOW-KRZEMIŃSKA Beata , HALDA Josef P. , CZARNOTA Paweł
Published: December 2011

Agonimia flabelliformis sp. nov. (Verrucariaceae, Ascomycota) is described as a new species from the Czech Republic, Germany and Great Britain. Except for the distinctive, flabelliform to minutely coralloid thallus the species mostly resembles A. allobata. It differs from other related species of Agonimia in the absence of cortical papillae and in ascospore size. The distinctness of the new species and its placement within the genus Agonimia is supported by analyses of mitochondrial small subunit ribosomal DNA sequences from several samples of the taxon, and from many other representatives of Verrucariales including newly sequenced A. repleta and A. vouauxii. Additionally, ITS rDNA sequence data supports the distinction of A. flabelliformis from A. allobata. However, A. allobata was found to be highly variable and relationships, as well as the monophyly of taxa within Agonimia, are still unresolved and need further investigation.
A new saxicolous species of Diploschistes (Thelotremataceae) from the Canary Islands
Authors: PÉREZ-VARGAS Israel , HERNÁNDEZ-PADRÓN Consuelo , PAZ Pedro L. PÉREZ DE , ELIX John A.
Published: December 2011

Diploschistes albopruinosus is described as new to science. This species is found on siliceous rocks in La Caldera de Taburiente National Park (La Palma, Canary Islands). A description of the species is given together with notes on its chemistry, distribution, ecology and taxonomy. Related lichen taxa are discussed.
Species delimitations in the Cladonia cariosa group (Cladoniaceae, Ascomycota)
Authors: PINO-BODAS Raquel , BURGAZ Ana Rosa , MARTÍN María P. , LUMBSCH H. Thorsten
Published: December 2011

Phenotypic characters, either morphological or chemical, have shown to be insufficient to delimit species boundaries in the genus Cladonia. The present study addresses the circumscription of species within the Cladonia cariosa group, examining a number of specimens of the currently accepted taxa Cladonia cariosa, C. symphycarpa, C. acuminata, C. subcariosa and C. latiloba. We employed maximum likelihood and Bayesian methods of phylogenetic reconstructions based on DNA sequences of ITS, rpb2 and ef1α regions. Our results show that the C. cariosa group consists of at least four phylogenetic lineages. It is also shown that each of these lineages is chemically variable, which restricts the taxonomic value of the chemical differences within the group. However, anatomical differences, such as squamule surface and cortex structure, were found to correlate with the distinct lineages found in the phylogenetic analysis. This result confirms the taxonomic value of the cortical surface under SEM, as was found in other lichen groups.
C1 metabolism and CVD outcomes in older adults
Authors: McNulty Helene , Strain J. J. , Pentieva Kristina , Ward Mary
Published: December 2011

CVD is the most common cause of death in people over 65 years. This review considers the latest evidence for a potential protective effect of C1 donors (folate and the metabolically related B-vitamins) in CVD. Such an effect may or may not be mediated via the role of these nutrients in maintaining plasma homocysteine concentrations within a desirable range. Despite predictions from epidemiological studies that lowering plasma homocysteine would reduce cardiovascular risk, several secondary prevention trials in at-risk patients published since 2004 have failed to demonstrate a benefit of homocysteine-lowering therapy with B-vitamins on CVD events generally. All these trials were performed in CVD patients with advanced disease; thus current evidence suggests that intervention with high-dose folic acid is of no benefit in preventing another event, at least in the case of heart disease. The evidence at this time, however, is stronger for stroke, with meta-analyses of randomised trials showing that folic acid reduces the risk of stroke, particularly in people with no history of stroke. Genetic studies provide convincing evidence to support a causal relationship between sub-optimal B-vitamin status and CVD. People homozygous for the common C677T variant in the gene encoding the folate-metabolising enzyme, methylenetetrahydrofolate reductase (MTHFR), typically have a 14–21% higher risk of CVD. Apart from folate, riboflavin is required as a co-factor for MTHFR. New evidence shows that riboflavin intervention results in marked lowering of blood pressure, specifically in patients with the MTHFR 677TT genotype. This novel gene–nutrient interaction may provide insights as to the mechanism that links C1 metabolism with CVD outcomes.
Range-only fuzzy Voronoi-enhanced localization of mobile robots in wireless sensor networks
Authors: Herrero D. , Martínez H.
Published: December 2011

Wireless Sensor Network (WSN) localization has shown a growing research interest, thanks to the expected proliferation of WSN applications. This work is focused on indoor localization of a mobile robot in a WSN using only inter-node range measurements, which are estimated by radio frequency signal strength attenuation. These measurements are affected by different sources of uncertainty that make them highly noisy and unreliable. The proposed approach makes use of fuzzy logic for modeling and dealing with such uncertain information. Besides, the position estimation is enhanced using a rough description of indoor environment. The experiments show that the proposed localization approach (i) is fault-tolerant, (ii) results feasible in low-density WSNs, and (iii) provides better position estimations than well-known localization methods when the position measurements are affected by high uncertainty.
Cognitive Function and Assistive Technology for Cognition: A Systematic Review
Authors: Gillespie Alex , Best Catherine , O'Neill Brian
Published: December 2011

The relationship between assistive technology for cognition (ATC) and cognitive function was examined using a systematic review. A literature search identified 89 publications reporting 91 studies of an ATC intervention in a clinical population. The WHO International Classification of Functioning, Disability and Health (ICF) was used to categorize the cognitive domains being assisted and the tasks being performed. Results show that ATC have been used to effectively support cognitive functions relating to attention, calculation, emotion, experience of self, higher level cognitive functions (planning and time management) and memory. The review makes three contributions: (1) It reviews existing ATC in terms of cognitive function, thus providing a framework for ATC prescription on the basis of a profile of cognitive deficits, (2) it introduces a new classification of ATC based on cognitive function, and (3) it identifies areas for future ATC research and development. (JINS, 2012,18, 1–19)
OUTPUT FLUCTUATIONS IN THE G-7: AN UNOBSERVED COMPONENTS APPROACH
Authors: Mitra Sinchan , Sinclair Tara M.
Published: December 2011

This paper proposes a multivariate unobserved-components model to simultaneously decompose the real GDP for each of the G-7 countries into its respective trend and cycle components. In contrast to previous literature, our model allows for explicit correlation between all the contemporaneous trend and cycle shocks. We find that all the G-7 countries have highly variable stochastic permanent components for output, even once we allow for structural breaks. We also find that common restrictions on the correlations between trend and cycle shocks are rejected by the data. In particular, we find that correlations across permanent and transitory shocks are important both within and across countries.
Quantitative High-Resolution Transmission Electron Microscopy of Single Atoms
Authors: Gamm Björn , Blank Holger , Popescu Radian , Schneider Reinhard , Beyer André , Gölzhäuser Armin , Gerthsen Dagmar
Published: December 2011

Single atoms can be considered as the most basic objects for electron microscopy to test the microscope performance and basic concepts for modeling image contrast. In this work high-resolution transmission electron microscopy was applied to image single platinum, molybdenum, and titanium atoms in an aberration-corrected transmission electron microscope. The atoms are deposited on a self-assembled monolayer substrate that induces only negligible contrast. Single-atom contrast simulations were performed on the basis of Weickenmeier-Kohl and Doyle-Turner form factors. Experimental and simulated image intensities are in quantitative agreement on an absolute intensity scale, which is provided by the vacuum image intensity. This demonstrates that direct testing of basic properties such as form factors becomes feasible.
On the implementation ofGNU Prolog
Authors: DIAZ DANIEL , ABREU SALVADOR , CODOGNET PHILIPPE
Published: December 2011

GNU Prologis a general-purpose implementation of the Prolog language, which distinguishes itself from most other systems by being, above all else, a native-code compiler which produces stand-alone executables which do not rely on any bytecode emulator or meta-interpreter. Other aspects which stand out include the explicit organization of the Prolog system as a multipass compiler, where intermediate representations are materialized, in Unix compiler tradition.GNU Prologalso includes an extensible and high-performance finite-domain constraint solver, integrated with the Prolog language but implemented using independent lower-level mechanisms. This paper discusses the main issues involved in designing and implementingGNU Prolog: requirements, system organization, performance, and portability issues as well as its position with respect to other Prolog system implementations and the ISO standardization initiative.
Autonomous data describe North Atlantic spring bloom
Authors: Fennel K. , Cetinić I. , D'Asaro E. , Lee C. , Perry M. J.
Published: December 2011

Each spring, increasing sunlight and associated changes in the ocean structure trigger rapid growth of phytoplankton across most of the North Atlantic Ocean north of 30°N. The bloom, one of the largest in the world, is a major sink for atmospheric carbon dioxide and a prototype for similar blooms around the world. Models of the ocean carbon cycle, a necessary component of climate models, need to accurately reproduce the biological, chemical, and physical processes occurring during these blooms. However, a paucity of detailed observations severely limits efforts to evaluate such models.
Updating the science of atmospheric electricity
Authors: Pinto Osmar , Williams Earle R.
Published: December 2011

XIV International Conference on Atmospheric Electricity; Rio de Janeiro, Brazil, 7–12 August 2011 The main goal of the XIV International Conference on Atmospheric Electricity (ICAE 2011) was to provide a comprehensive description of the status of knowledge in the field of atmospheric electricity, as well as to provide an opportunity for extensive interaction among researchers in this field. The history of the ICAE goes back to the first conference held in May 1954 in Portsmouth, N. H. The conference was attended by 51 scientists from 10 countries, and only three topics were addressed: fair weather electricity, thunderstorm electrification, and lightning.
New method improves estimation of subdaily rainfall statistics
Authors: Balcerak Ernie
Published: December 2011

Daily rainfall data are readily available, but in many locations there are few rain gauges that provide subdaily rainfall data. Hydrologic models often deal with this problem by generating synthetic hourly rainfall series by assuming a temporal scaling behavior. However, Beuchat et al. found that the particular scaling laws may apply only to specific climates, and it is difficult to produce regional scaling laws. Therefore, they propose a new approach to estimating subdaily rainfall statistics using a mathematical technique called multivariate adaptive regression splines (MARS).
Revisiting sea level and energy budgets
Authors: Balcerak Ernie
Published: December 2011

Various factors contribute to sea level rise, including changing groundwater storage, thermal expansion of the oceans, and melting glaciers and ice sheets. However, studies that add up the observed contributions from these effects have not been able to account for the entire observed sea level rise over the past several decades. To help resolve the discrepancy, Church et al. revisited sea level budgets and considered sea level and Earth's energy budgets together using new and updated estimates of all contributing factors for the past several decades, including a new estimate of groundwater depletion. They were able to account for the entire observed sea level change from 1972 to the present.
How did Martian polar gullies form?
Authors: Balcerak Ernie
Published: December 2011

Gullies on Mars have been pointed to as evidence of the presence of flowing liquid water. However, gullies also exist in Mars's polar regions, where temperatures are too low to support liquid water. Other processes have been proposed to explain the origin of gullies but have not been confirmed. For instance, sediment lying on top of a seasonal accumulation of carbon dioxide (CO2) frost could flow like a fluid if the frost sublimes (turns to gas directly from the solid stage) quickly enough. This fluidized sediment could form gullies.
Solar cycle variations of the Cluster spacecraft potential and its use for electron density estimations
Authors: Lybekk B. , Pedersen A. , Haaland S. , Svenes K. , Fazakerley A. N. , Masson A. , Taylor M. G. G. T. , Trotignon J.‐G.
Published: December 2011

A sunlit conductive spacecraft, immersed in tenuous plasma, will attain a positive potential relative to the ambient plasma. This potential is primarily governed by solar irradiation, which causes escape of photoelectrons from the surface of the spacecraft, and the electrons in the ambient plasma providing the return current. In this paper we combine potential measurements from the Cluster satellites with measurements of extreme ultraviolet radiation from the TIMED satellite to establish a relation between solar radiation and spacecraft charging from solar maximum to solar minimum. We then use this relation to derive an improved method for determination of the current balance of the spacecraft. By calibration with other instruments we thereafter derive the plasma density. The results show that this method can provide information about plasma densities in the polar cap and magnetotail lobe regions where other measurements have limitations.
Matching ASCAT and QuikSCAT winds
Authors: Bentamy Abderrahim , Grodsky Semyon A. , Carton James A. , Croizé‐Fillon Denis , Chapron Bertrand
Published: December 2011

Surface winds from two scatterometers, the Advanced scatterometer (ASCAT), available since 2007, and QuikSCAT, which was available through November 2009, show persistent differences during their period of overlap. This study examines a set of collocated observations during a 13‐month period November 2008 through November 2009, to evaluate the causes of these differences. A difference in the operating frequency of the scatterometers leads to differences that this study argues depend on rain rate, wind velocity, and SST. The impact of rainfall on the higher frequency QuikSCAT introduces biases of up to 1 m s−1 in the tropical convergence zones and along the western boundary currents even after rain flagging is applied. This difference from ASCAT is reduced by some 30% to 40% when data for which the multidimensional rain probabilities > 0.05 is also removed. An additional component of the difference in wind speed seems to be the result of biases in the geophysical transfer functions used in processing the two data sets and is parameterized here as a function of ASCAT wind speed and direction relative to the mid‐beam azimuth. After applying the above two corrections, QuikSCAT wind speed remains systematically lower (by 0.5 m s−1) than ASCAT over regions of cold SST < 5°C. This difference appears to be the result of temperature‐dependence in the viscous damping of surface waves which has a greater impact on shorter waves and thus preferentially impacts QuikSCAT. The difference in wind retrievals also increases in the storm track corridors as well as in the coastal regions where the diurnal cycle of winds is aliased by the time lag between satellites.
Seasonal and interannual variability in the temperature structure around the tropical tropopause and its relationship with convective activities
Authors: Nishimoto Eriko , Shiotani Masato
Published: December 2011

Seasonal and interannual variability in the tropical tropopause temperatures and its relationship with convective activities are examined by using the ECMWF 40 year reanalysis data and NOAA/OLR data. Low temperatures generally occur over the equator in the eastern hemisphere and extend northwestward and southwestward in the subtropics to form a horseshoe‐shaped structure. Because this structure resembles a stationary wave response known as the Matsuno‐Gill pattern, which is a superposition of the Rossby and Kelvin responses, the two preliminary indices are defined to represent the two responses. The horseshoe‐shaped structure index is then calculated from the two indices. The seasonal cycle in the horseshoe‐shaped structure index is significantly related to that observed in convective activities adjacent to three monsoon regions: the South Asian monsoon (SoAM) and the North Pacific monsoon (NPM) areas during the northern summer and the Australian monsoon (AUM) area during the southern summer. The convective activities in the SoAM and NPM areas individually influence the horseshoe‐shaped structure. During the northern summer, interannual variation in the horseshoe‐shaped structure index in the NPM area is related to that observed in convective activities associated with the El Niño–Southern Oscillation (ENSO) cycle with about a half‐year time lag. In the SoAM area, the variation is mainly controlled by isolated high temperatures, which are surrounded by the horseshoe‐shaped temperature structures and are not related to convective activities. During the southern summer, the horseshoe‐shaped structure index is related to convective anomalies associated with the ENSO cycle, shifting eastward in El Niño years.
A solar escalator: Observational evidence of the self‐lifting of smoke and aerosols by absorption of solar radiation in the February 2009 Australian Black Saturday plume
Authors: de Laat A. T. J. , Stein Zweers D. C. , Boers R. , Tuinder O. N. E.
Published: December 2011

We present an analysis of the evolution of the smoke plume caused by the Black Saturday bushfires, which started on 7 February 2009 in the Australian state of Victoria. Within 3 days this smoke plume was located at altitudes between 15 and 20 km thousands of kilometers away from its source region. Standard explanations for high tropospheric and lower stratospheric absorbing aerosols are either volcanic eruptions or pyroconvection. We performed a detailed analysis of various satellite observations, forward trajectory calculations, and meteorological conditions during the fire episode, yet we could not find evidence of either of these standard mechanisms explaining the observed plume evolution. Pyroconvection observed within the initial smoke plumes remained predominantly below 10 km altitude. Furthermore, there are not active volcanoes in the region. We postulate that the subsequent rise beyond approximately 10 km altitude during the first 3 days after the fires started was caused by absorption of short‐wave solar radiation in the plume. Observations indicate that the plume was highly absorptive and optically very thick. One‐dimensional plume height radiative transfer calculations with realistic assumptions about the optical properties of the smoke show that the plume could rise to 16–18 km after 5 days and up to 20 km after 10 days. The plume rise exhibits a characteristic step‐like time evolution that tracks the variation in diurnal insolation and resembles an escalator. We argue that this is the first time that this mechanism, known as “self‐lifting,” has been observed on a large scale. The key features of this mechanism and its implications are briefly discussed.
Uncertainty in dual permeability model parameters for structured soils
Authors: Arora B. , Mohanty B. P. , McGuire J. T.
Published: December 2011

Successful application of dual permeability models (DPM) to predict contaminant transport is contingent upon measured or inversely estimated soil hydraulic and solute transport parameters. The difficulty in unique identification of parameters for the additional macropore‐ and matrix‐macropore interface regions, and knowledge about requisite experimental data for DPM has not been resolved to date. Therefore, this study quantifies uncertainty in dual permeability model parameters of experimental soil columns with different macropore distributions (single macropore, and low‐ and high‐density multiple macropores). Uncertainty evaluation is conducted using adaptive Markov chain Monte Carlo (AMCMC) and conventional Metropolis‐Hastings (MH) algorithms while assuming 10 out of 17 parameters to be uncertain or random. Results indicate that AMCMC resolves parameter correlations and exhibits fast convergence for all DPM parameters while MH displays large posterior correlations for various parameters. This study demonstrates that the choice of parameter sampling algorithms is paramount in obtaining unique DPM parameters when information on covariance structure is lacking, or else additional information on parameter correlations must be supplied to resolve the problem of equifinality of DPM parameters. This study also highlights the placement and significance of matrix‐macropore interface in flow experiments of soil columns with different macropore densities. Histograms for certain soil hydraulic parameters display tri‐modal characteristics implying that macropores are drained first followed by the interface region and then by pores of the matrix domain in drainage experiments. Results indicate that hydraulic properties and behavior of the matrix‐macropore interface is not only a function of saturated hydraulic conductivity of the macroporematrix interface (Ksa) and macropore tortuosity (lf) but also of other parameters of the matrix and macropore domains.
The Role of Cognitive Dissonance in Social Networks
Authors: Akiba Henrique , Machado Dias Alvaro , Oda Eduardo , Ikeda Ricardo , Oliveira Mauri
Published: December 2011

Context: The principles behind the process of creating new, spontaneous sequences out of previously ordered non-declarative stimuli have been scarcely addressed and, for such reason, remain highly unknown.

Objective:

This paper has four interconnected goals:(1) Introduce a new software-based neuropsychological test that can be used as a means to assess key aspects of the way people order and reorder non-declarative stimuli, based upon cognitive dissonance principles; (2) introduce a mathematical approach to the latter in ordering/re-ordering of non-declarative stimuli;(3) assess whether the principles of cognitive dissonance in ordering/re-ordering hold for a cohort of young adults with upper socio-economic level;(4) access the extent to which the same holds for children and adolescents and trace a curve of maturation of cognitive dissonance in ordering/re-ordering. Methods: Our multi-age and multi-language social Network Test implies the two stages, first the subject must order figures of human faces in order of preference, next, the software provides him with different pairs of figures which the subject must fulfill in order to built the intermediate arrays that he believe to interconnect the original pair. Our mathematical model is centered around the relation defined by increases in the distance separating these different pairs of figures in the initial order (distances 1, 5 and 11) and related increases in the mean number of intermediate arrays placed in the re-ordering phase; 105 subjects were tested.

Results:

The tendency to produce reorders that are consonant to the one produced in the initial phase increases with age. This trend inspired us to propose a cognitive dissonance index in spontaneous ordering/reordering of non-declarative stimuli, which may formalize the operation of a previously unknown cognitive dimension of the human mind and may serve as an index of cognitive maturation. To the extent that further studies endorse these perspectives, the tests, formulas, and theoretical principals may support new diagnostic methods and explorations in cognitive science.
Physics and modelling of microwave streamers at atmospheric pressure
Authors: Chaudhury Bhaskar , Boeuf Jean-Pierre , Zhu Guo-Qiang , Pascal Olivier
Published: December 2011

Breakdown in a microwave field leads to the formation of plasmoids that expand in a direction parallel to the incident electric field and form microwave streamers. A two-dimensional model based on solutions of Maxwell’s equations coupled with a quasineutral description of the plasma is used to study the formation of a single streamer formed and confined at the antinode between two incident linearly polarized waves with opposed wave vectors. We discuss the parameters controlling the plasma density in the streamer, the field distribution and elongation speed for incident fields of frequency F = 110 GHz at atmospheric pressure, p = 760 Torr, in dry air (other conditions with the same F/p can be deduced from simple scaling laws). The results show that the large electric field at the tips of the streamer (responsible for the streamer elongation parallel to the incident field) presents successive maxima and minima during the streamer extension. These maxima and minima are associated with resonant effects. When the applied field is only slightly above the critical field, the streamer growth may stop at the first field minimum.
Correlation between polarity distribution and piezoelectric response of solution-deposited Zn1-xLixO films
Authors: Nagase Toshimi , Kamohara Toshihiro , Nishikubo Keiko , Fukamachi Satoru , Shobu Kazuhisa , Akiyama Morito
Published: December 2011

We report a correlation between polarity distribution and piezoelectric response of Li-doped zinc oxide (Zn1-xLixO) films prepared by a facile chemical solution deposition (CSD) method. The correlation supports the importance of controlling the polarity distribution for obtaining high piezoelectric response of ZnO films. Although the Zn1-xLixO films were easily prepared on Inconel substrates by heating randomly-stacked nanoparticle films, Zn0.97Li0.03O and Zn0.94Li0.06O films showed high piezoelectric response of 5.6–5.8 pC/N and high O-polarity distribution ratio of 76–74%. This study presents the CSD method is promising as a low-cost and large-area fabrication method of piezoelectric ZnO films.
Role of material properties and mesostructure on dynamic deformation and shear instability in Al-W granular composites
Authors: Olney K. L. , Chiu P. H. , Lee C. W. , Nesterenko V. F. , Benson D. J.
Published: December 2011

Dynamic experiments with Al-W granular/porous composites revealed qualitatively different behavior with respect to shear localization depending on bonding between Al particles. Two-dimensional numerical modeling was used to explore the mesomechanics of the large strain dynamic deformation in Al-W granular/porous composites and explain the experimentally observed differences in shear localization between composites with various mesostructures. Specifically, the bonding between the Al particles, the porosity, the roles of the relative particle sizes of Al and W, the arrangements of the W particles, and the material properties of Al were investigated using numerical calculations. It was demonstrated in simulations that the bonding between the soft Al particles facilitated shear localization as seen in the experiments. Numerical calculations and experiments revealed that the mechanism of the shear localization in granular composites is mainly due to the local high strain flow of soft Al around the rigid W particles causing localized damage accumulation and subsequent growth of the meso/macro shear bands/cracks. The rigid W particles were the major geometrical factor determining the initiation and propagation of kinked shear bands in the matrix of soft Al particles, leaving some areas free of extensive plastic deformation as observed in experiments and numerical calculations.
Electric field compensation and sensing with a single ion in a planar trap
Authors: Narayanan S. , Daniilidis N. , Möller S. A. , Clark R. , Ziesel F. , Singer K. , Schmidt-Kaler F. , Häffner H.
Published: December 2011

We use a single ion as a movable electric field sensor with accuracies on the order of a few V/m. For this, we compensate undesired static electric fields in a planar radio frequency trap and characterize the static field and its curvature over an extended region along the trap axis. We observe a strong buildup of stray charges around the loading region on the trap resulting in an electric field of up to 1.3 kV/m at the ion position. We also find that the profile of the stray field remains constant over a time span of a few months.
Resistive transition, anomalous magnetocapacitance, and ferroelectric phenomena observed in charge ordered canted antiferromagnetic La0.5Ba0.5FeO3 perovskite
Authors: Masud Md G. , Ghosh Arijit , Chaudhuri B. K. , Hsiao K. , Yang H. D.
Published: December 2011

We report multifunctional properties of the charge disproportionate correlated electronic system La0.5Ba0.5FeO3 synthesized by conventional solid state reaction route. The bulk sample undergoes semiconductor–metal like transition at TSM = 102 K showing appreciable magnetoresistance (∼20%) around TSM even at a low field (∼0.5 T). A crossover of electrical conduction mechanism from Mott’s variable range hopping to small polaron hopping occurs around 210 K, well above TSM. Analysis of the transport, magnetic susceptibility, and magnetization data in the light of de Gennes proposal indicates the formation of canted antiferromagnetic spin order preceded by charge ordering in La0.5Ba0.5FeO3. Nonsaturation behavior and nonlinearity of the M-H curve at low temperature and at high field (∼5 T), confirms the canted spin order. The observed resistive transition is considered to be associated with the onset of weak ferromagnetic ordering in the canted antiferromagnetic spin state of the materials. Moreover, novel ferroelectric like behavior showing electric field-polarization hysteresis loop below the charge ordering temperature along with anomalous magnetocapacitance response representing magnetoelectric coupling is also observed. In the low temperature regime spin lattice coupling might be responsible for exhibiting magnetocapacitance in La0.5Ba0.5FeO3. Such multifunctional character implies fundamental as well as technological importance of this sample.
Epitaxial growth of Fe and MgO layers on GaAs (001): Microstructure and magnetic property
Authors: Kim Kyung-Ho , Kim Hyung-jun , Ahn Jae-Pyung , Lee Seung-Cheol , Ok Won Sung , Woo Choi Jun , Chang Joonyeon
Published: December 2011

Microstructure and the corresponding magnetic property of epitaxial MgO and subsequent Fe layers in situ grown on GaAs(001) substrates are investigated as a function of the epitaxial layer thicknesses. It is found that the MgO layers retain a 1.6 nm thick Mg-rich amorphous layer at the initial stage of the MgO growths regardless of its total thickness. Systematic x-ray diffraction analysis reveals that the MgO layers are under in-plane compressive strain which is partially relaxed as the total MgO thickness increases from 4 to 20 nm. The misfit strain within the MgO layers results in three-dimensional Fe islands forming at lower thickness with two different zone axis of [010] or [11¯0]. Furthermore, the islands coalesce as the nominal thickness increases, resulting in serpentine-shaped Fe islands. Finally, it completely covers the underlying MgO layers, forming an epitaxial Fe layer at the nominal thickness higher than 10 nm. The three-dimensional Fe islands at the initial stage show superparamagnetism, which becomes ferromagnetic as the Fe forms a two-dimensional layer.
Effect of the vertical composition gradient of active layer on the performance of bulk-heterojunction organic photovoltaic cell
Authors: Nam Young Min , Huh June , Jo Won Ho
Published: December 2011

A computational model is developed to investigate the effect of vertical composition gradient on the photovoltaic properties of organic photovoltaic cell based on poly (3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). When the photovoltaic properties of model devices with systematic variation of vertical composition distribution are calculated by using this model, it is found that the efficiency increases almost linearly as the concentrations of P3HT and PCBM become richer near anode and cathode, respectively. The larger exciton generation near anode due to enrichment of P3HT near the anode contributes mainly to an increase of the device efficiency by compensating the lower hole mobility of P3HT with shorter pathway to the anode.
(Electro)mechanical behavior of selectively solvated diblock/triblock copolymer blends
Authors: Vargantwar Pruthesh H. , Brelander Sarah M. , Krishnan Arjun S. , Ghosh Tushar K. , Spontak Richard J.
Published: December 2011

Thermoplastic elastomeric triblock copolymers swollen with a midblock-selective solvent form a highly elastic physical network that can exhibit remarkable electromechanical properties (high actuation strains and electromechanical efficiency with low hysteresis upon cycling) as dielectric elastomers. One unexplored means of controllably altering the midblock network and the corresponding (electro)mechanical properties at constant copolymer concentration is to substitute non-network-forming diblock for triblock copolymer molecules. In this study, we demonstrate that the incorporation of composition-matched diblock molecules into selectively solvated triblock systems results in softer materials that are less physically crosslinked and thus capable of undergoing electroactuation at reduced electric fields.
Magnetic field modulated dielectric relaxation behavior of Pt/BiScO3-PbTiO3/La0.7Sr0.3MnO3 heterostructure in metal-insulator transition region: An equivalent-circuit method
Authors: Zhu Junyu , Yang Jing , Bai Wei , Duan Chungang , Zhang Shuai , Wang Genshui , Dong Xianlin , Remiens Denis , Tang Xiaodong
Published: December 2011

Utilizing temperature and magnetic field dependent dielectric spectroscopy, two different dielectric relaxation processes, both accompanied with prominent positive magnetodielectric (MD) effects, were observed in Pt/BiScO3-PbTiO3/La0.7Sr0.3MnO3 (Pt/BSPT/LSMO) heterostructure. An equivalent circuit model is established to quantitatively describe the relaxation data well. The simulation results elucidated that one relaxation process can be attributed to magnetic order associated BSPT/LSMO interfacial relaxation with abnormal dynamics feature. Another one is due to the external contact interface contributions. Both relaxation dynamics can be tuned, via magnetic field controlled localization of free interfacial charges, to induce MD effects in BSPT/LSMO interfaces and nonmagnetic Pt/BSPT contacts.
Field confinement and quality factor of the multilayer cavity resonators
Authors: Yogesh N. , Subramanian V.
Published: December 2011

The field confinement aspect of a multilayer cavity resonator formed by a one-dimensional photonic crystal with prism wedge configuration is described in this paper. The prism wedge consists of alternating dielectric layers and is used for the construction of polygon multilayered structures with different symmetries like C4v-square and C6v-hexagon. Field confinement is studied by finding the resonant modes and quality factors (Q) of the proposed geometries. The computed Q factors for the two-dimensional geometries (the third dimension is taken to be infinity) are of the order of 103–107. On the other hand, for the finite height of the cavity, the estimated Q factor is found to be of the order of 104. An attempt has been taken to achieve the vertical confinement of light for a few of the resonant modes so that the proposed cavities may be implemented for microwave applications, especially in spectroscopic techniques.
The effects of laser welding on heterogeneous immunoassay performance in a microfluidic cartridge
Authors: Mäntymaa Anne , Halme Jussi , Välimaa Lasse , Kallio Pasi
Published: December 2011

Sealing of a microfluidic cartridge is a challenge, because the cartridge commonly contains heat-sensitive biomolecules that must also be protected from contamination. In addition, the objective is usually to obtain a sealing method suitable for mass production. Laser welding is a rapid technique that can be accomplished with low unit costs. Even though the technique has been widely adopted in industry, the literature on its use in microfluidic applications is not large. This paper is the first to report the effects of laser welding on the performance of the heterogeneous immunoassay in a polystyrene microfluidic cartridge in which biomolecules are immobilized into the reaction surface of the cartridge before sealing. The paper compares the immunoassay performance of microfluidic cartridges that are sealed either with an adhesive tape or by use of laser transmission welding. The model analyte used is thyroid stimulating hormone (TSH). The results show that the concentration curves in the laser-welded cartridges are very close to the curves in the taped cartridges. This indicates, first, that laser welding does not cause any significant reduction in immunoassay performance, and second, that the polystyrene cover does not have significant effect on the signal levels. Interestingly, the coefficients of variance between parallel samples were lower in the laser-welded cartridges than in the taped cartridges.
Intrinsic nanoscale phase separation in miscible mixtures and supramolecular assemblies
Authors: Zhang Lei
Published: December 2011

A model is used to describe the intrinsic nanoscale phase separation in miscible mixtures and supramolecular assemblies. Phase-separated nanostructures related to size-dependent surface tension, molecular structural factors and strong interphase interactions exist in miscible mixtures and supramolecular assemblies. The intrinsic nanoscale phase separation may exist universally in miscible mixtures.
Enhancement of exciton photoluminescence intensity caused by the distortion of the crystal plane originating from the internal strain in a ZnO wafer
Authors: Takeuchi Hideo
Published: December 2011

We have investigated the relation between the exciton photoluminescence intensity and distortion of the crystal plane in a ZnO wafer. The present investigation utilizes the following two characterization methods that complement the result of the photoluminescence measurement: a circular polariscopic measurement and a θ-2θ x-ray diffraction measurement. The circular polariscopic map clarifies the distribution of the strain exists in the ZnO wafer. The strain found in the circular polariscopic analysis indicates the existence of the crystal-plane distortion, which is confirmed from the appearance of the forbidden reflection line in the x-ray diffraction pattern. The photoluminescence measurements at different positions sensitive to the crystal-plane distortion were performed on the basis of the above-mentioned complementary information. It is found that the crystal-plane distortion causes the enhancement of the exciton photoluminescence intensity. The responsible factor is attributed to the suppression of the exciton diffusion caused by the crystal-plane distortion. This is in contrast to the usual interpretation that the lowering of the crystalline quality leads to the reduction of the exciton photoluminescence intensity; namely, the aid of complementary information is essential to precisely interpret the photoluminescence intensity.
Toward a New Countermovement: A Framework for Interpreting the Contradictory Interventions of Migrant Civil Society Organizations in Urban Labor Markets
Authors: Martin Nina
Published: December 2011

Low-wage migrant workers in the United States confront a perilous labor market, where wages are low, the risk of injury on the job is high, and the fear of apprehension by immigration authorities is widespread. There is increasing empirical evidence that civil society organizations are becoming involved in mediating labor-market problems, but work remains to be done in developing a robust theoretical conception of why such organizations are involved in this arena and how we might evaluate the impacts of their interventions. This paper presents a framework for interpreting the role of migrant civil society organizations as labor-market intermediaries, by extending Karl Polanyi's theory of the ‘double movement’ and more recent writing to neoliberalism and precarious work. On the basis of data collected from migrant nonprofit organizations in Chicago, I theorize migrant civil society organizations as part of the creation of a new countermovement that protects the interests of both workers and employers from the destructive nature of an unregulated labor market, as predicted by Polanyi. I catalogue organizations' responses to precarious work and create a generalizable framework for evaluating the contingent outcomes of their strategies. Organizations' work is interpreted as complex and sometimes contradictory: the potential to shield workers and advocate for progressive change is in constant tension with the neoliberal patterns of state and economic restructuring that such organizations can support.
Synchrotron Radiation Spectroscopic Techniques as Tools for the Medicinal Chemist: Microprobe X-Ray Fluorescence Imaging, X-Ray Absorption Spectroscopy, and Infrared Microspectroscopy
Authors: Dillon Carolyn Therese
Published: December 2011

This review updates the recent advances and applications of three prominent synchrotron radiation techniques, microprobe X-ray fluorescence spectroscopy/imaging, X-ray absorption spectroscopy, and infrared microspectroscopy, and highlights how these tools are useful to the medicinal chemist. A brief description of the principles of the techniques is given with emphasis on the advantages of using synchrotron radiation-based instrumentation rather than instruments using typical laboratory radiation sources. This review focuses on several recent applications of these techniques to solve inorganic medicinal chemistry problems, focusing on studies of cellular uptake, distribution, and biotransformation of established and potential therapeutic agents. The importance of using these synchrotron-based techniques to assist the development of, or validate the chemistry behind, drug design is discussed.
Levels of mRNA for bone morphogenetic proteins, their receptors and SMADs in goat ovarian follicles grown in vivo and in vitro
Authors: Costa J. J. N. , Passos M. J. , Leitão C. C. F. , Vasconcelos G. L. , Saraiva M. V. A. , Figueiredo J. R. , van den Hurk R. , Silva J. R. V.
Published: December 2011

This study investigated the stability of housekeeping genes (glyceraldehyde-3-phosphate dehydrogenase, β-tubulin, β-actin, phosphoglycerate kinase (PGK), 18S rRNA, ubiquitin and ribosomal protein 19) and the levels of mRNA for bone morphogenetic protein-2 (BMP-2), -4 (BMP-4), -6 (BMP-6), -7 (BMP-7) and -15 (BMP-15), their receptors (BMPR-IA, -IB and -II) and Similar to Mothers Against Decapentaplegic (SMADs) (-1, -5 and -8) in goat follicles of 0.2, 0.5 and 1.0 mm, as well as in secondary follicles before and after culture for 18 days. β-tubulin and PGK were the most stable housekeeping genes and the levels of mRNA for BMP-2 in follicles of 0.2 mm were higher than in follicles of 0.5 and 1.0 mm. For BMP-4, -6 and -7, the highest levels of mRNA were found in follicles of 1.0 mm. The expression of BMPR-IB was higher in follicles of 0.2 mm, whereas the levels of BMPR-II were higher in follicles of 0.5 mm. The levels of mRNA for SMAD-5 were higher in follicles of 0.2 mm, whereas SMAD-8 had higher levels in 0.5-mm follicles. After culture, follicles showed increased levels of mRNA for BMP-2 and reduced mRNA for BMP-4, BMP-7, BMPR-IA and SMAD-5. In conclusion, β-tubulin and PGK are the most stable reference genes, and BMPs, their receptors and SMADs have variable levels of mRNA in the follicular size classes analysed.