bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple small‐size coupled‐fed uniplanar PIFA for multiband clamshell mobile phone application
Authors: Kang Ting‐Wei , Wong Kin‐Lu
Published: September 2009

In this study, a simple uniplanar printed PIFA occupying a small area of 10 × 40 mm2for achieving multiband operation in the clamshell mobile phone is presented. The proposed PIFA is formed by a simple shorted radiating strip coupled‐fed by a simple feeding strip and is mounted at the hinge of the clamshell mobile phone; further, the upper ground plane is connected to the main ground plane using an extended connecting strip. With the coupling feed and the connection arrangement between the main and upper ground planes, the proposed PIFA itself is not only an efficient radiator, it can also excite the two ground planes of the clamshell mobile phone as an efficient radiator (dipole‐like resonant modes are excited). Thus, with a small occupying area and a simple structure for the proposed PIFA, two wide operating bands at lower and higher frequencies can be provided to cover GSM850/900/1800/1900/UMTS bands for WWAN operation. The antenna also meets the 1‐g SAR specification of 1.6 W/kg required for practical applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2805–2810, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24756
A compact seven‐section rat‐race hybrid coupler incorporating PBG cells
Authors: Opozda S. , Kurgan P. , Kitlinski M.
Published: September 2009

A conventional rat‐race coupler has been doubly miniaturized: (i) characteristic impedances and electrical lengths of microstrip sections have been adequately modified as the first step of size reduction and (ii) T‐shaped PBG cells have been implemented to diminish strip section length as the second step of circuit miniaturization. The experimental results show good agreement with theoretical characteristics. Furthermore, the proposed seven‐section PBG coupler enabled the achievement of 85% scale of size reduction in the final design, which proves the attractiveness of presented miniaturization method. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2910–2913, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24789
Vertically meander‐folded, shorted‐patch antennas
Authors: Holub Alois , Polívka Milan
Published: September 2009

In this study, a novel miniaturized microstrip patch antenna based on meander‐folded, shorted‐patch (SP) structure is introduced. The technique enables a decrease of the original quarter‐wavelength patch length approximately by the factor 1/N, where N is the number of the vertically placed patch plates above the ground plane. The antenna operational principle is explained with the help of E‐field distribution and can be interpreted as SP with vertically meander‐folded cavity. Further modification of the top patch plate to ensure symmetrical radiation pattern is proposed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2938–2942, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24790
Four‐wave mixing wavelength conversion for a novel return‐to‐zero FSK signal at 43 Gb/s
Authors: Liu X. , Hou C. , Zhen X. , Chi N. , Wen H. , Zhang H.
Published: September 2009

Transparent wavelength conversion based on four‐wave mixing(FWM) in a SOA and in a HNDSF is experimentally demonstrated for a 43Gb/s return‐to‐zero frequency shift keying(FSK) signal. When a return‐to‐zero FSK signal propagates through the SOA or HNDSF, the wavelength will be converted and the waveform will be reshaped due to the FWM effect. Our experiments show that the performance of the converted signal is enhanced due to the reshaping characteristics, which indicates the potential of FWM as bit rate transparent wavelength conversion mechanism in future high‐speed systems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2856–2858, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24800
A novel short length half‐width microstrip leaky wave antenna with suppressed back lobes
Authors: Chiou Yi‐Lin , Wu Jin‐Wei , Huang Jie‐Huang , Jou Christina F.
Published: September 2009

A novel short half‐width microstrip leaky wave antenna (MLWA) with suppressed back lobes is introduced. The design contains an oblique shape termination and a linked square metal with a grounded via hole. The oblique shape termination changes the direction of the reflected wave, and a linked square metal with a grounded via hole guides the remainder power of the reflected wave to the ground plane. As a result, the large back lobe of the short half‐width MLWA could be suppressed. The measured results show that the proposed design (length of only 1 λ0) improves the back lobes by 9 dB at 4.7 GHz compared with the original half‐width MLWA. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 3024–3026, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24805
Involvement of the PKC family in regulation of early development
Authors: Kalive Madhavi , Faust James J. , Koeneman Brian A. , Capco David G.
Published: September 2009

Protein kinase C (PKC) isotypes have been implicated in a number of key steps during gametogenesis, fertilization, and early development. The 11‐member family of PKC isotypes, many with different cofactor requirements for activation, can provide for differential activation of the specific kinases. In addition the enrichment of particular PKC isotypes to unique locations within gametes, zygotes, and early embryos likely promotes specific substrate interactions. Evidence exists to indicate involvement of PKC isotypes during sperm capacitation and the acrosome reaction, during resumption of meiosis in the oocytes, regulating the spindle organization in meiosis I and II, at fertilization, in the pronuclei, in the mitotically dividing blastomeres of the embryo, and at the plasma membranes of blastomeres at the time of embryonic compaction. Evidence also exists for crosstalk with other signaling pathways and one or more isotypes of PKC appear to be active at each major developmental transition. Mol. Reprod. Dev. 77: 95–104, 2010. © 2009 Wiley‐Liss, Inc.
Acrylamide–itaconic acid superabsorbent polymers and superabsorbent polymer/mica nanocomposites
Authors: Foungfung Daungtawan , Phattanarudee Siriwan , Seetapan Nispa , Kiatkamjornwong Suda
Published: September 2009

Superabsorbent polymer acrylamide (AM)/itaconic acid (IA) and its nanocomposite were synthesized by redox polymerization in an aqueous solution of both monomers with mica used as an inorganic additive. The influences of IA concentration, mica content, and crosslinker concentration on the water absorption and physical properties of the superabsorbent polymer and its nanocomposite were examined. Water absorbency in artificial urine by the synthesized copolymers, and the gel strength of the superabsorbent copolymers and their nanocomposites, were tested with loads of 0.28 or 0.70 psi. Transmission electron micrographs and X‐ray diffraction confirmed that the polymer chains were successfully intercalated into the silicate layers in the mica. The water absorbency and the artificial urine absorbency of the composite with an AM‐to‐IA mole ratio of 95:5, 0.2% mol N‐MBA, and 5% w/w mica were 748 ± 5  and 76 ± 2 g g−1, respectively, whilst the neat copolymer achieved only 640 ± 7 and 72 ± 2 g g−1 in water and artificial urine, respectively. The viscoelastic behavior suggested that the swollen gel of the nanocomposites exhibited mechanical stability and elasticity. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of green tea on erythrocytes antioxidant status of different age rats intoxicated with ethanol
Authors: Wojciech Łuczaj , Ewa Zapora , Elżbieta Skrzydlewska
Published: September 2009

The aim of this paper is to evaluate the effect of green tea on the erythrocyte antioxidant system of ethanol‐intoxicated rats, as well as its efficacy in the prevention of lipid peroxidation. Rats (2, 12 and 24 months old) were fed on a control or an ethanol Lieber‐DeCarli diet with and without green tea (7 g/L) for 5 weeks. Examination included the activity of antioxidant enzymes and the level of both non‐enzymatic antioxidants and lipid peroxidation marker in rat erythrocytes. It was shown that ageing was accompanied by changes in the antioxidant enzymes activity – increase in the SOD and CAT activity and decrease in GSSG‐R and GSH‐Px activity, as well as in the level of non‐enzymatic antioxidants – GSH, vitamin A and vitamin E. The increase in the level of lipid peroxidation marker – MDA – was also observed. Green tea consumption partially prevented lipid peroxidation process, especially in erythrocytes of 2‐ and 12‐month‐old rats. It was proved that ethanol administration caused a statistically significant decrease in the activity/level of the examined antioxidants in all age groups (the most significant in the case of 24‐month‐old rats) of rats, as well as an increase in the MDA level. However, ingestion of green tea by ethanol‐intoxicated rats partially prevented the decrease in activity/level of all examined antioxidant parameters, as well as protected lipids against peroxidation in all age groups of rats. Obtained results confirm the beneficial effect of green tea on erythrocyte antioxidant abilities. Copyright © 2009 John Wiley & Sons, Ltd.
Cone‐beam computed tomography of the maxillofacial region—an update
Authors: Kau Chung How , Božič Marko , English Jeryl , Lee Robert , Bussa Harry , Ellis Randy K.
Published: September 2009

Background

During the last few years, craniomaxillofacial diagnosis of the head has been confronted with an increasing number of innovations and improvements. The main progress occurred following the introduction of cone‐beam technology in computed tomography in the 1990s. The number of manufacturers and devices using this technology for the maxillofacial region is growing rapidly and they are now becoming readily available.

Materials

This article focuses on cone‐beam computed tomography (CBCT) devices applied to the maxillofacial region. CBCT serves as a bridge from two dimensions (2D) to three dimensions (3D), with lower irradiation than conventional CT. Different manufacturers and models are now available to satisfy the different needs of clinicians.

Results

A recent review of the manufacturers found 23 CBCT devices on the market. The specifications, applications and other issues of currently available CBCT devices are presented and discussed.

Conclusions

3D imaging is developing at a very fast pace. New technologies and machines are emerging and CBCT is becoming readily available. Due to the growing demand for the technology based on the needs of clinicians, there is now a wide and growing selection of devices on the market. Some of the new advances now mean that CBCT imaging should be a well‐considered option in maxillofacial imaging. Copyright © 2009 John Wiley & Sons, Ltd.
The effects of flow regulation and climatic variability on obstructed drainage and reverse flow contribution in a Northern river–lake–Delta complex, Mackenzie basin headwaters
Authors: Peters D. L. , Buttle J. M.
Published: September 2009

A distinctive hydrological feature of the Lake Athabasca–Peace–Athabasca Delta (LA‐PAD) complex is that flow in channels that drain the system reverses direction when stage on the Peace River exceeds that for the central lakes. This river's hydrology has experienced natural and human induced changes since 1968. This study investigates the importance of spring break‐up and open‐water induced outflow obstruction and reverse flow contributions to annual lake level maxima under natural (1960–1967), regulated (1976–2004) and naturalized (1976–1996) flow regimes.

Obstructed and reverse flow events during spring break‐up were common prior to and following flow regulation, suggesting that natural climatic variability in source areas below the W.A.C. Bennett Dam exerted a strong influence on their occurrence. Antecedent hydrological conditions, such as fall freeze‐up lake level, break‐up magnitude, peak spring flow and initial open‐water lake level were significantly associated with annual lake level maxima. During the summer period, lake level was linked to sustained high flows on the Peace River. The river obstructed outflow and contributed reverse flow to the LA‐PAD in each year prior to 1968. Following regulation, however, more than half the years did not experience any open‐water obstruction and/or reversal, and those that did were characterized by smaller events. The average estimated duration of obstruction was more than two weeks shorter and reverse flow volume was reduced by ∼90% under a regulated regime compared to a simulated naturalized flow regime. This implied a lowered potential for lateral lake expansion into the delta floodplain in some years. The regulated hydrology could produce large stormflow and high lake levels, but only under extreme climatic events in areas below the dam and/or human‐induced alterations to normal reservoir operation. Copyright © 2009 Crown in the right of Canada and John Wiley & Sons, Ltd.
Bounds on causal effects in randomized trials with noncompliance under monotonicity assumptions about covariates
Authors: Chiba Yasutaka
Published: September 2009

In randomized trials with nonrandom noncompliance, the causal effects of a treatment among the entire population cannot be estimated in an unbiased manner. Therefore, several authors have considered the bounds on the causal effects. Here, we propose bounds by applying an idea of VanderWeele (Biometrics 2008; 64:702–706), who showed that the sign of the unmeasured confounding bias can be determined under monotonicity assumptions about covariates in the framework of observational studies. In randomized trials with noncompliance by switching the treatment, we show that the lower or upper bound on the expectation of the potential outcome becomes the expectation from the per‐protocol analysis under monotonicity assumptions similar to those of VanderWeele. In particular, the monotonicity assumptions can yield both the lower and the upper bounds on causal effects when the monotonic relationship between the covariates and the treatment actually received depends on the treatment assigned. The results are extended to cases of noncompliance by subjects not receiving any treatment. Although the monotonicity assumptions are not themselves identifiable, they are nonetheless reasonable in some situations. Copyright © 2009 John Wiley & Sons, Ltd.
Projection pursuit
Authors: Jee J. Rodney
Published: September 2009

Projection pursuit is a technique for finding highly informative low‐dimensional projections of multivariate data for visual inspection by an analyst. When data of dimension m are reduced to dimension p (where typically p = 2 is the most useful for viewing by scatter plots), the method consists of defining a measure of information content in two dimension and optimizing that measure or index as a function of two m‐dimensional projection vectors to find the most informative projection. The main ideas that have guided research in projection pursuit are reviewed with the emphasis on ideas leading to practical implementations. The most common indices investigated and used are described, and comparative studies of these indices as used in projection pursuit are reviewed. Other aspects of implementation such as the choice of optimization algorithm are also covered. Copyright © 2009 Wiley Periodicals, Inc., A Wiley Company

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Analysis of High Dimensional Data
Positive solutions of a nonlinear Sturm–Liouville boundary-value problem
Authors: Cerda Patricio , Ubilla Pedro
Published: September 2009

We establish the existence of positive solutions of the Sturm–Liouville problem

where

We assume g and $\hat{q}$ to be non-negative, continuous functions, a(s) is a positive continuous function, c≥0, p>1, and the function h is sub-quadratic with respect to u′. We combine a priori estimates with a fixed-point result of Krasnosel'skii to obtain the existence of a positive solution.
Integer points of analytic functions in a half-plane
Authors: Fletcher Alastair N. , Langley J. K.
Published: September 2009

It is shown that if f is an analytic function of sufficiently small exponential type in the right half-plane, which takes integer values on a subset of the positive integers having positive lower density, then f is a polynomial.
Uniform approximation by elementary operators
Authors: Magajna Bojan
Published: September 2009

On a separable C*-algebra A every (completely) bounded map which preserves closed two-sided ideals can be approximated uniformly by elementary operators if and only if A is a finite direct sum of C*-algebras of continuous sections vanishing at ∞ of locally trivial C*-bundles of finite type.
The lichen genus Phylloblastia (Verrucariaceae) in the Iberian Peninsula, with a new species from Western Europe
Authors: LLOP Esteve , GÓMEZ-BOLEA Antonio
Published: September 2009

The foliicolous genus Phylloblastia is recorded for the first time in the Iberian Peninsula where it is represented by three species: P. fortuita sp. nov. from several localities in the north-east of Spain, P. dispersa, a new record for Europe and reported for the first time outside the tropics, and P. inexpectata. A key to the European species is provided.
Exploring causes of the decline of the lichenLecanora conizaeoidesin Britain: effects of experimental N and S applications
Authors: MASSARA A. C. , BATES J. W. , BELL J. N. B.
Published: September 2009

The crustose lichenLecanora conizaeoideshas declined markedly around London with progressively diminishing sulphur dioxide pollution of the air since the 1960s. To identify the immediate causes of its decline, we applied S in the form of bisulphite (0·2 & 2 mM) and sulphate (2 mM), and N as nitrate (2 mM) to relict colonies of the lichen on beech trunks in a plantation in Windsor Forest. Growth of the lichen was monitored by estimating changes in percentage cover. By the end of a 25-month period of two-weekly treatments, all the chemical treatments had resulted in significant decreases in cover ofL. conizaeoidescompared to distilled water controls, with the 2 mM bisulphite causing the greatest loss. Bark surface pH was also lowered by the chemical treatments, but most by the 2 mM bisulphite applications. Similar results were obtained in two laboratory experiments where the nutrient applications were repeated under a controlled environment and thallus area monitored photographically. No evidence was obtained to support the hypothesis that growth ofL. conizaeoidesis stimulated by an elevated sulphur supply. We conclude that the disappearance of the lichen is linked to gradual increase in bark pH caused by the combined effects of a marked reduction in SO2emissions and rising emissions of NH3.
Personality and Psychological Health in Persons with Mild Cognitive Impairment
Authors: Clément Francis , Belleville Sylvie , Bélanger Sara , Chassé Véronique
Published: September 2009

Plusieurs études ont documenté le profil cognitif des individus ayant un trouble cognitif léger (TCL), mais très peu se sont intéressées à leur santé psychologique et à leurs traits de personnalité ainsi qu’aux interactions entre ces facteurs et la cognition. Dans cette étude, 27 personnes âgées saines et 30 personnes ayant un TCL ont été soumises à une évaluation neuropsychologique et ont rempli des questionnaires portant sur la santé psychologique, le bien-être, la personnalité, l’auto-efficacité et l’auto-actualisation. Les résultats indiquent que les individus ayant un TCL sont plus déprimés, anxieux, hostiles et ont moins de bien-être que ce que rapporte un groupe de personnes âgées sans trouble de cognition. De plus, nos résultats révèlent une association positive entre le niveau de dépression des personnes ayant un TCL et la sévérité de leurs atteintes cognitives. En revanche, aucune différence n’est observée entre les groupes sur les échelles de personnalité. Ainsi, alors que la détresse psychologique est présente chez les personnes ayant un TCL, celles-ci ne montrent pas de différence de traits de personnalité par rapport aux personnes âgées n’éprouvant pas de troubles cognitifs.
Gender Role, Life Satisfaction, and Wellness: Androgyny in a Southwestern Ontario Sample
Authors: Gale-Ross Reagan , Baird Anne , Towson Shelagh
Published: September 2009

Dans cette étude, nous avons effectué des recherches sur les relations entre le rôle sexuel et le fonctionnement physique autodéclaré, à partir d’un échantillon d’aînés vivant dans la communauté. Cent deux participants ont été recrutés (55 femmes, 47 hommes) dans les associations pour personnes âgées de Windsor, Ontario. Nous avons mené des analyses de variance pour chacun des sexes afin de comparer l’autoévaluation du fonctionnement physique, du bien-être et de la satisfaction de vivre des participants qui diffèrent dans la classification de leur rôle sexuel. Pour ce qui est des femmes âgées classées comme androgynes, le rôle sexuel avait des effets importants sur le bien-être général et la satisfaction de vivre, mais n’avait pas d’effet sur le fonctionnement physique autodéclaré. Venant à l’appui du modèle androgénique d’ajustement optimal de Bem, les analyses a posteriori ont révélé que les femmes qui se sont autodéclarées androgynes ont un meilleur niveau global de bien-être que les autres. L’autoévaluation du fonctionnement physique et du bien-être général chez les hommes âgés n’a pas démontré de différences importantes en fonction du rôle sexuel. Les limitations et les implications font l’objet de discussions.
Feasibility of Biological Specimen Collection for the Canadian Longitudinal Study on Aging (CLSA) Biorepository
Authors: Balion Cynthia M. , Raina Parminder S. , Wolfson Christina , Kirkland Susan A. , Keys Judy L. , Griffith Lauren E. , Pelletier Amélie , Uniat Jennifer , McQueen Matthew J.
Published: September 2009

La collecte de spécimens biologiques est une partie intégrale de beaucoup d’études épidémiologiques longitudinales. Il est important d’obtenir un haut taux de satisfaction de la part des participants pour que leur participation soit continue et pour assurer une qualité élevée des échantillons pour avoir des mesures précises pour les biomarqueurs. Nous avons réalisé une étude pour évaluer ces questions sur la collecte d’échantillons proposée pour l’Étude longitudinale canadienne sur le vieillissement (ÉLCV). Parmi les 85 participants recrutés, 65 ont été dirigés vers un laboratoire d’hôpital ou un laboratoire privé. Environ 100 mL de sang et un prélèvement aléatoire d’urine ont été collectés pour chaque participant, pour un total de 2 108 aliquots d’échantillon. Les niveaux de qualité ont été atteints pour plus de 90 % des échantillons et étaient semblables pour les échantillons collectés dans les deux laboratoires. Plus de 90 % des participants ont exprimé que leur satisfaction par rapport à la collecte était bonne ou excellente, et 84 % serait prêts à répéter la collecte dans un à trois ans.
Diagnostik der koronaren Herzkrankheit – Teil 2: Belastungs-EKG und Myokardperfusionsszintigraphie
Authors: Maeder  , Zellweger
Published: September 2009

Belastungs-EKG und Myokardperfusionsszintigraphie (MPS) stellen die belastungsinduzierte myokardiale Ischämie dar, wobei die MPS sensitiver ist. Das Belastungs-EKG ist die Untersuchung der Wahl bei Patienten mit normalem Ruhe-EKG und guter Belastbarkeit. Die MPS kann mit Ergometer-Belastung, pharmakologischer Belastung oder kombiniert durchgeführt werden und ist eine geeignete Untersuchung bei Patienten mit nicht-interpretierbarem EKG und/oder schlechter Belastbarkeit. Beide Untersuchungen sind geeignet für die Weiterabklärung von Patienten mit Thoraxschmerz und intermediärer Vortest-Wahrscheinlichkeit einer relevanten koronaren Herzkrankheit. Für Patienten mit hoher Vortest-Wahrscheinlichkeit können beide Untersuchungen zur Risikostratifizierung verwendet werden. Beide Tests sind nicht sinnvoll für Patienten mit Thoraxschmerz und tiefer Vortest-Wahrscheinlichkeit oder als Screening-Untersuchung bei unselektionierten asymptomatischen Patienten.
A mechanism for electrostatic solitary structures in the Earth's magnetosheath
Authors: Lakhina G. S. , Singh S. V. , Kakad A. P. , Goldstein M. L. , Viñas A. F. , Pickett J. S.
Published: September 2009

Electrostatic solitary waves (ESWs) have been observed in the Earth's magnetosheath region by Cluster. A mechanism for the generation of these structures in terms of electron‐acoustic solitons and double layers is discussed. The model simulates the magnetosheath plasma by a four‐component plasma system consisting of core electrons, two counterstreaming electron beams, and one type of ions. The analysis is based on the fluid equations and the Poisson equation, and employs the Sagdeev pseudopotential techniques to investigate the solitary waves. The electric field amplitudes, the time durations, and the propagation speeds of the solitary structures predicted by the model are in good agreement with the observed electric fields, pulse widths, and speeds of the electrostatic bipolar pulses.
A systematic analysis of the structure and (hyper)polarizability of donor-acceptor substituted polyacetylenes using a Coulomb-attenuating density functional
Authors: Borini Stefano , Limacher Peter A. , Lüthi Hans Peter
Published: September 2009

In this paper we perform a systematic investigation on all-trans polyacetylene chains of different lengths, end-capped with moieties of different donor or acceptor natures and different strengths, to infer useful structure/property relationship rules and behavioral patterns. The values for bond length alternation (BLA), longitudinal polarizability, and first and second hyperpolarizabilities have been computed with the Coulomb-attenuating density function (CAM-B3LYP), using response theory. A comparison of the relative effect that each end-capping combination contributes to BLA, linear, and nonlinear optical coefficients has been performed. This results in useful insights and general rules to ad hoc tailoring the molecular response for a specific characteristic.
Computational simulation of coupled nonequilibrium discharge and compressible flow phenomena in a microplasma thruster
Authors: Deconinck Thomas , Mahadevan Shankar , Raja Laxminarayan L.
Published: September 2009

The microplasma thruster (MPT) concept is a simple extension of a cold gas micronozzle propulsion device, where a direct-current microdischarge is used to preheat the gas stream to improve the specific impulse of the device. Here we study a prototypical MPT device using a detailed, self-consistently coupled plasma and flow computational model. The model describes the microdischarge power deposition, plasma dynamics, gas-phase chemical kinetics, coupling of the plasma phenomena with high-speed flow, and overall propulsion system performance. Compared to a cold gas micronozzle, a significant increase in specific impulse is obtained from the power deposition in the diverging section of the MPT nozzle. For a discharge voltage of 750 V, a power input of 650 mW, and an argon mass flow rate of 5 SCCM (SCCM denotes cubic centimeter per minute at STP), the specific impulse of the device is increased by a factor of ∼1.5 to about 74 s. The microdischarge remains mostly confined inside the micronozzle and operates in an abnormal glow discharge regime. Gas heating, primarily due to ion Joule heating, is found to have a strong influence on the overall discharge behavior. The study provides a validation of the MPT concept as a simple and effective approach to improve the performance of micronozzle cold gas propulsion devices.
Third-order nonlinear optical properties of a one- and two-electron spherical quantum dot with and without a hydrogenic impurity
Authors: Şahin Mehmet
Published: September 2009

In this study, a detailed investigation of the nonlinear optical properties of a spherical quantum dot (QD) containing one and two electrons has been carried out. First, intersublevel linear, third-order, and total absorptions of both single- and double-electron QDs have been investigated for cases with (i.e., D0 and D− donor) and without impurity. Second, linear, third-order, and total refractive indices have been examined in the same structure. In the calculation of optical properties, for the density of electrons in the QD considered, some symbolic values chosen are not similar to those in previous studies. The full numeric matrix diagonalization technique has been employed in determining sublevel energy eigenvalues and their wave functions. The Poisson–Schrödinger equations have been solved self-consistently in the Hartree approximation. In addition, the quantum mechanical many-body effects have been taken into account in local density approximation. The results are presented as a function of QD radii, photon intensities, and photon energies. It is found out that although magnitudes of the linear absorption coefficients are the same for cases with and without impurity, the third-order ones are larger, and so the total absorption coefficients are smaller in the case without impurity. It is also observed that the size of the QD and the intensity of the illumination have drastic effects on nonlinear optical properties.
1.54

μ
m
emission mechanism in Er-doped silicon-rich silicon oxides
Authors: Jang Y. R. , Yoo K. H. , Ahn J. S. , Kim C. , Park S. M.
Published: September 2009

Silicon-rich silicon oxide (SRSO) and Er-doped SRSO (SRSO:Er) thin films were formed by pulsed laser deposition, and characterized by photoluminescence (PL), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), and UV-visible transmission in order to clarify the 1.54 μm emission mechanism in the SRSO:Er films. The oxygen content of the films was varied by the adjustment of oxygen partial pressure. The behavior of the 1.54 μm PL with oxygen partial pressure combined with XPS and XRD data show that the 1.54 μm emission intensity is related to the amount of SiOx phase. This conclusion is well supported by the measurements of UV-visible transmission. In many previous papers, the 1.54 μm emission is associated with Si nanocrystals, but in our study the correlation between 1.54 μm emission intensity and the amount of SiOx phase is much clearer.
Thermally induced permittivity enhancement in La-doped ZrO2 grown by atomic layer deposition on Ge(100)
Authors: Lamagna L. , Wiemer C. , Baldovino S. , Molle A. , Perego M. , Schamm-Chardon S. , Coulon P. E. , Fanciulli M.
Published: September 2009

La-doped ZrO2 thin films grown by O3-based atomic layer deposition directly on Ge(100) exhibit a dielectric constant of 29. Upon annealing in N2 at 400 °C, a high κ value >40 is extracted for film thickness below 15 nm. Compositional depth profiling allows to correlate this observation with a remarkable Ge interdiffusion from the substrate which is consistent with the stabilization of the tetragonal ZrO2 phase. Ge interaction with the oxide stack and the formation of a germanate-like interfacial region, which acts as an electrical passivation for the Ge surface, are also investigated.
Vibrational self-trapping in beta-sheet structures observed with femtosecond nonlinear infrared spectroscopy
Authors: Bodis Pavol , Schwartz Erik , Koepf Matthieu , Cornelissen Jeroen J. L. M. , Rowan Alan E. , Nolte Roeland J. M. , Woutersen Sander
Published: September 2009

Self-trapping of NH-stretch vibrational excitations in synthetic β-sheet helices is observed using femtosecond infrared pump-probe spectroscopy. In a dialanine-based β-sheet helix, the transient-absorption change upon exciting the NH-stretch mode exhibits a negative absorption change at the fundamental frequency and two positive peaks at lower frequencies. These two induced-absorption peaks are characteristic for a state in which the vibrational excitation is self-trapped on essentially a single NH-group in the hydrogen-bonded NH⋯OC chain, forming a small (Holstein) vibrational polaron. By engineering the structure of the polymer we can disrupt the hydrogen-bonded NH⋯OC chain, allowing us to eliminate the self-trapping, as is confirmed from the NH-stretch pump-probe response. We also investigate a trialanine-based β-sheet helix, where each side chain participates in two NH⋯OC chains with different hydrogen-bond lengths. The chain with short hydrogen bonds shows the same self-trapping behavior as the dialanine-based β-sheet helix, whereas in the chain with long hydrogen bonds the self-trapping is too weak to be observable.
A Seeman–Bohlin geometry for high-resolution nanosecond x-ray diffraction measurements from shocked polycrystalline and amorphous materials
Authors: Milathianaki D. , Hawreliak J. , McNaney J. M. , El-Dasher B. S. , Saculla M. D. , Swift D. C. , Lorenzana H. E. , Ditmire T.
Published: September 2009

We report on a focusing x-ray diffraction geometry capable of high-resolution in situ lattice probing from dynamically loaded polycrystalline and amorphous materials. The Seeman–Bohlin-type camera presented here is ideally suited for time-resolved x-ray diffraction measurements performed on high energy multibeam laser platforms. Diffraction from several lattice planes of ablatively shock-loaded 25 μm thick Cu foils was recorded on a focusing circle of diameter D=100 mm with exceptional angular resolution limited only by the spectral broadening of the x-ray source. Excellent agreement was found between the density measured using x-ray diffraction and that inferred from Doppler velocimetry and the known shock Hugoniot of Cu. In addition, x-ray diffraction signal was captured from an amorphous material under static conditions.
Influence of interlayer on the performance of stacked white organic light-emitting devices
Authors: Chen Ping , Xue Qin , Xie Wenfa , Xie Guohua , Duan Yu , Zhao Yi , Liu Shiyong , Zhang Liying , Li Bin
Published: September 2009

Stacked white organic light-emitting devices (WOLEDs) comprising of blue fluorescent and orange phosphorescent emissive units employing tri(8-hydroxyquinoline) aluminum (Alq3):Mg/MoO3 as charge generation layer are fabricated. The working mechanism of Alq3:Mg/MoO3 is also discussed using a simple method. We demonstrate charge-carrier separation takes place only in MoO3 layer. Stacked WOLED with better performance was obtained by adjusting the thickness of MoO3. The stacked WOLED with efficiency of 39.2 cd/A has excellent color stability with the Commission Internationale de l’Eclairage coordinates only changing from (0.407, 0.405) to (0.398, 0.397) when luminance increases from 22 to 10 000 cd/m2.
A mechanical Kerr effect in deformable photonic media
Authors: Pernice W. H. P. , Li Mo , Tang H. X.
Published: September 2009

We theoretically introduce a mechanism for achieving the mechanical analog of optical Kerr nonlinearity. By exploiting optomechanical interactions in deformable waveguide structures, a nonlinear phase shift proportional to the optical field intensity is induced. Resulting Kerr coefficients several orders of magnitude larger than the intrinsic silicon optical Kerr coefficient are predicted.
Current manipulation of a vortex confined in a micron-sized Fe19Ni81 disk
Authors: Yamaguchi Akinobu , Motoi Keiichi , Miyajima Hideki , Hirohata Atsufumi , Yamaoka Takehiro , Uchiyama Tsuyoshi , Utsumi Yuichi
Published: September 2009

By measuring a rectifying planer Hall effect, we have manipulated a vortex core trapped in a single layered Fe19Ni81 disk dependent upon the magnitude of a dc current simultaneously applied with an rf current and a magnetic field. The observed behavior is attributed to a single vortex translational mode. The resonance frequency of the translational mode is found to be almost proportional to the magnitude of the dc current and to be governed by the shape of the energy potential well defined by the disk shape.
The strong influence of heat losses on the accurate measurement of thermal diffusivity using lock-in thermography
Authors: Salazar Agustín , Mendioroz Arantza , Fuente Raquel
Published: September 2009

In modulated photothermal experiments the lateral thermal diffusivity can be obtained from the slope of the linear relation between the phase of the surface temperature and the distance to the heating spot. However, this slope is greatly affected by heat losses so that the measured thermal diffusivity is overestimated, especially for thin samples of poor thermal conducting materials. In this paper we definitely identify the physical mechanism responsible for the overestimation of the diffusivity as heat conduction to the surrounding gas. Accurate measurements of the thermal diffusivity using the “slope method” have been obtained by keeping the sample in vacuum.
Neighbourhood Effects on Youth Educational Achievement in the Netherlands: Can Effects Be Identified and Do They Vary by Student Background Characteristics?
Authors: Sykes Brooke , Kuyper Hans
Published: September 2009

Adding to the growing body of research examining neighbourhood effects in European contexts, this study investigates the associations between the educational achievement of Dutch youth and their neighbourhood conditions. We further consider whether these associations vary by student socioeconomic status (SES), gender, or nativity. Results from a multilevel analysis of 17 836 secondary school students living in 3085 neighbourhoods indicate significant relationships between several dimensions of the neighbourhood context and educational achievement. Student SES and nativity appear to moderate some of these effects. In particular, we find the negative effect of neighbourhood disadvantage to be almost entirely restricted to native youth. The achievement outcomes of students with higher levels of SES also appear to be less affected by neighbourhood affluence and disadvantage than those of lower-SES students. Our results suggest that the impact of neighbourhood conditions on certain groups of youth may be obscured in studies that measure average neighbourhood effects across all individuals. Future research which examines neighbourhood effects and mechanisms across subgroups of youth, and which examines the links between the neighbourhood, family, and school contexts, can help us to better determine the neighbourhood's role in youth education.
Governing the Clean Development Mechanism: Global Rhetoric versus Local Realities in Carbon Sequestration Projects
Authors: Boyd Emily
Published: September 2009

Global agreements have proliferated in the past ten years. One of these is the Kyoto Protocol, which contains provisions for emissions reductions by trading carbon through the Clean Development Mechanism (CDM). The CDM is a market-based instrument that allows companies in Annex I countries to offset their greenhouse gas emissions through energy and tree offset projects in the global South. I set out to examine the governance challenges posed by the institutional design of carbon sequestration projects under the CDM. I examine three global narratives associated with the design of CDM forest projects, specifically North–South knowledge politics, green developmentalism, and community participation, and subsequently assess how these narratives match with local practices in two projects in Latin America. Findings suggest that governance problems are operating at multiple levels and that the rhetoric of global carbon actors often asserts these schemes in one light, while the rhetoric of those who are immediately involved locally may be different. I also stress the alarmist's discourse that blames local people for the problems of environmental change. The case studies illustrate the need for vertical communication and interaction and nested governance arrangements as well as horizontal arrangements. I conclude that the global framing of forests as offsets requires better integration of local relationships to forests and their management and more effective institutions at multiple levels to link the very local to the very large scale when dealing with carbon sequestration in the CDM.
Barium Stars: Theoretical Interpretation
Authors: Husti Laura , Gallino Roberto , Bisterzo Sara , Straniero Oscar , Cristallo Sergio
Published: September 2009

Barium stars are extrinsic Asymptotic Giant Branch (AGB) stars. They present the s-enhancement characteristic for AGB and post-AGB stars, but are in an earlier evolutionary stage (main sequence dwarfs, subgiants, red giants). They are believed to form in binary systems, where a more massive companion evolved faster, produced the s-elements during its AGB phase, polluted the present barium star through stellar winds and became a white dwarf. The samples of barium stars of Allen & Barbuy (2006) and of Smiljanic et al. (2007) are analysed here. Spectra of both samples were obtained at high-resolution and high S/N. We compare these observations with AGB nucleosynthesis models using different initial masses and a spread of 13C-pocket efficiencies. Once a consistent solution is found for the whole elemental distribution of abundances, a proper dilution factor is applied. This dilution is explained by the fact that the s-rich material transferred from the AGB to the nowadays observed stars is mixed with the envelope of the accretor. We also analyse the mass transfer process, and obtain the wind velocity for giants and subgiants with known orbital period. We find evidence that thermohaline mixing is acting inside main sequence dwarfs and we present a method for estimating its depth.
BBC broadcasters’ unpublished views on Jung: Priestley and Freeman
Authors: Schoenl William
Published: September 2009

This article shows the unpublished views of J. B. Priestley and John Freeman, two significant BBC broadcasters on Jung. Priestley puzzled over individuation in Jung, but his most striking comment was that H. G. Baynes’ death in 1943 had been an enormous loss to Jungians in Britain. Freeman strikingly commented on Marie-Louise von Franz as the most important person in Jung's life after Emma Jung's death, on Jung's immediate entourage regarding him as a sort of demi-God in his last years, and on India perhaps being more than he could sustain. Freeman acted as co-ordinating editor of Jung's final book, Man and his symbols.
RAYTEC: a new code for electron cyclotron radiative transport modelling of fusion plasmas
Authors: Albajar F. , Bornatici M. , Engelmann F.
Published: September 2009

As it was recognized that local electron cyclotron (EC) wave power losses can be a competitive contribution to the 1D electron power balance for reactor-grade tokamak plasmas in regimes as anticipated for steady-state operation, a systematic effort is ongoing to improve the modelling capability for the radial profile of EC wave emission. This effort aims at generating a hierarchy of codes that cover the non-local behaviour of EC wave transport for inhomogeneous plasmas and in the presence of reflecting walls with increasingly improved accuracy and also provide sufficient computational efficiency for being usable in 1D transport studies. The recently developed code RAYTEC, which explicitly addresses the geometrical effects present in toroidal plasmas with arbitrary cross-section, is described and used to investigate the impact of elongation of the plasma cross-section and of toroidicity on the angular dependence of the EC radiation field, on the profile of the net EC wave power density lost from the plasma and on the total EC power loss for ITER-like plasma conditions. Furthermore, a comparison is made with the results of simpler models in use to describe both local and total EC power losses as well as with ones obtained from analytical formulae that are introduced on the basis of Trubnikov's formula for EC power emission.
HHsvm: fast and accurate classification of profile–profile matches identified by HHsearch
Authors: Dlakić Mensur
Published: September 2009

Motivation: Recently developed profile–profile methods rival structural comparisons in their ability to detect homology between distantly related proteins. Despite this tremendous progress, many genuine relationships between protein families cannot be recognized as comparisons of their profiles result in scores that are statistically insignificant.

Results: Using known evolutionary relationships among protein superfamilies in SCOP database, support vector machines were trained on four sets of discriminatory features derived from the output of HHsearch. Upon validation, it was shown that the automatic classification of all profile–profile matches was superior to fixed threshold-based annotation in terms of sensitivity and specificity. The effectiveness of this approach was demonstrated by annotating several domains of unknown function from the Pfam database.

Availability: Programs and scripts implementing the methods described in this manuscript are freely available from http://hhsvm.dlakiclab.org/.

Contact:  mdlakic@montana.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Relation Between Adiposity and Disease Risk Factors in Mexican American Children
Authors: McFarlin Brian K , Johnston Craig A , Tyler Chermaine , O'Connor Daniel P , Strohacker Kelley A , Reeves Rebecca , Jackson Andrew S , Foreyt John P
Published: September 2009

Objective:

Excess adiposity is associated with systemic low‐grade inflammation, which has been implicated in the pathophysiology of various diseases. The purpose of this study was to examine the relation between measures of adiposity and disease risk factors in Mexican American children participating in a weight loss intervention.

Subjects and Methods:

Boys and girls (N = 170; 13.3 ± 0.1 year) volunteered for additional testing from a larger study that demonstrated significant reduction in standardized body mass index. Insulin, C‐reactive protein, soluble cluster of differentiation 14, glucose, and cholesterol profile were assessed.

Results:

Linear mixed models regression showed that changes in adiposity (standardized body mass index and triceps skinfold) were significantly related with changes in total cholesterol (P = 0.01), triglycerides (P < 0.001), C‐reactive protein (P < 0.001), insulin (P < 0.001), Homeostasis model assessment of insulin resistance (P < 0.001), and high‐density lipoprotein (P < 0.001).

Conclusions:

The relation between measures of adiposity and disease risk factors was stable over time in children participating in an exercise/weight loss intervention. Also, our findings indicate that reducing adiposity results in an improvement of blood disease risk factors in Mexican American children.
The Heat Shock Response in Moss Plants Is Regulated by Specific Calcium-Permeable Channels in the Plasma Membrane
Authors: Saidi Younousse , Finka Andrija , Muriset Maude , Bromberg Zohar , Weiss Yoram G. , Maathuis Frans J.M. , Goloubinoff Pierre
Published: September 2009

Land plants are prone to strong thermal variations and must therefore sense early moderate temperature increments to induce appropriate cellular defenses, such as molecular chaperones, in anticipation of upcoming noxious temperatures. To investigate how plants perceive mild changes in ambient temperature, we monitored in recombinant lines of the moss Physcomitrella patens the activation of a heat-inducible promoter, the integrity of a thermolabile enzyme, and the fluctuations of cytoplasmic calcium. Mild temperature increments, or isothermal treatments with membrane fluidizers or Hsp90 inhibitors, induced a heat shock response (HSR) that critically depended on a preceding Ca2+ transient through the plasma membrane. Electrophysiological experiments revealed the presence of a Ca2+-permeable channel in the plasma membrane that is transiently activated by mild temperature increments or chemical perturbations of membrane fluidity. The amplitude of the Ca2+ influx during the first minutes of a temperature stress modulated the intensity of the HSR, and Ca2+ channel blockers prevented HSR and the onset of thermotolerance. Our data suggest that early sensing of mild temperature increments occurs at the plasma membrane of plant cells independently from cytosolic protein unfolding. The heat signal is translated into an effective HSR by way of a specific membrane-regulated Ca2+ influx, leading to thermotolerance.