bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic Investigations of Phase‐Separated Thermotropic Layers Based on UV Cured Acrylate Resins
Authors: Resch Katharina , Wallner Gernot M. , Lang Reinhold W.
Published: May 2008

Summary: In this paper spectroscopic techniques were adapted and applied to characterize the optical and morphological properties of thermotropic resins. Thermotropic films were prepared by variation of resin base and thermotropic additives. By UV/Vis/NIR spectroscopy the solar optical properties, the switching temperature, the switching process and the residual transmittance in the opaque state were determined. To control the sample temperature from ambient to 100 °C a conventional UV/Vis/NIR spectrophotometer equipped with an Ulbricht‐sphere was adapted by a heating stage. Additive content, distribution and scattering domain size were characterized by Differential Scanning Calorimetry, Attenuated Total Reflectance spectroscopy and microscopic techniques. For the investigated film types hemispheric solar transmittance values ranging from 80 to 87% and 75 to 85% were obtained in the clear and the scattering state, respectively. The diffuse solar transmittance values increased significantly from 14 to 40% below the switching temperature to 36 to 70% at elevated temperatures. The thermotropic resins exhibit a steep and rapid switching process with switching temperatures between 45 and 70 °C. The materials with the best switching properties are characterized by distinct differences in refractive index between the components, a uniform additive distribution and scattering domains with diameters below 1000 nm.
In situ ATR‐FTIR and SFM Studies on the Influence of Adsorption time on Deposition and Nanostructure of Poly(ethyleneimine)/Poly(acrylic acid) Multilayers
Authors: Muller M. , Paulik S.
Published: May 2008

Summary: The deposition and the nanostructure of polyelectrolyte multilayers (PEM) of branched poly(ethyleneimine)/poly(acrylic acid) (PEI/PAC) was studied in dependence of the adsorption time (tADS) of the individual steps. PEM were reproducibly deposited applying up to z = 20 adsorption steps at the fixed pH combination of 10/4 and polyelectrolyte concentration cPEL = 0.005 M in a flow cell using an automated valve system. in situ ATR‐FTIR spectroscopy and SFM were used for quantitative determination of deposited amount and thickness, respectively. A linear relation between PEL band integrals and thickness of thin PEM films was found. Varying tADS from 0.5 to 5 min in each of the adsorption steps resulted in a steep rise of the deposited PEM amount. For tADS > 5 min the deposition did only marginally increase. Evidence for the release of outermost located PEI upon PAC immersion (even step) and of outermost PAC upon PEI immersion (odd step) was obtained. SFM images on consecutively deposited PEM‐6 showed a slight increase in structure size and roughness for increasing tADS. These studies help to prepare polyelectrolyte based films with controlled thickness for the interaction with biofluids in the biomedical and food field.
Rheo‐optical FT‐IR Spectroscopy of LLDPE: Effect of Comonomer and Composite Materials
Authors: Plass M. , Streck R. , Nieto J. , Siesler H. W.
Published: May 2008

Summary: In order to further evaluate the potential of FT‐IR spectroscopic investigations on molecular processes during tensile testing experiments, the behavior of monolayer LLDPE films, made with ethylene‐butene and ethylene‐octene copolymers, was studied. Additionally, multilayer LLDPE films based on the same C4 and C8 copolymers were investigated. The stress‐strain data obtained from the monolayer films indicate differences in the strain hardening region. It seems that the film samples PE 469‐30‐2 (C4‐gas phase process) and PE 469‐30‐5 (C8 solution process) behave similarly whereas the strain hardening for the PE 469‐30‐3 (C4 solution process) requires lower stress values. The orientation function changes during the stretching of the films indicating that unfolding of the polymer chains occurs at lower strain for PE 469‐30‐5 (C8) than in the C4 materials. In the multilayer systems the Primplast 44 material (C8) shows a lower tendency for reorientation in the strain hardening region than the Coex 82 (C4) material. In this region of the stress‐strain curve the lamellar structure is already transformed into the fibrillar arrangement. Regarding the orientation behavior of the material above 200% strain, a small increase in fb was observed, which led to a decrease of fc. In the octene product possibly the bulky side chains influence the unfolding significantly, producing a higher resistance to unfolding and alignment along the stretching direction. In part, this is potentially caused by the more perfect lamellae in the octene copolymer, which do not include the side chains, while the butene copolymer may have weaker lamellae because they contain a fraction of the side chains which create defects. Consequently, the octene copolymer requires higher stress values to be stretched and finally results in a lower stretchability of this material, as observed on an industrial scale during pallet wrapping tests. Based on the ratio of the structural absorbance parameters of the signals at 729 and 719 cm−1 changes in the crystallinity were studied. For the continuous stretching experiment, no monoclinic phase was detected even after Fourier self‐deconvolution and peak fitting approaches. Literature data, however, describe that this crystalline transformation takes place as a result of mechanical deformation. Therefore, stepwise stretching experiments which allow an improvement of the spectral resolution to 1 cm−1 were carried out. In the deconvoluted spectra the monoclinic, orthorhombic and amorphous LLDPE modifications could be assigned. Ultimate stretchability and stretching force of the films, both monolayer and multilayer, was well correlated to the development of crystalline orientation in the films upon stretching. Other mechanical properties like Elmendorf tear and dart impact can also be better understood with these results.
The transcription factor Egr1 regulates the HIF‐1α gene during hypoxia
Authors: Sperandio Sabina , Fortin Jessyka , Sasik Roman , Robitaille Lynda , Corbeil Jacques , de Belle Ian
Published: May 2008

Using oligonucleotide expression microarrays we have examined the modulation of gene expression in the DU145 prostate cancer cell line. Our findings confirm that the Egr1 transcription factor is rapidly and transiently upregulated by hypoxia. Furthermore, we have demonstrated that HIF‐1α mRNA is also transiently upregulated, as is its target gene VEGF. To elucidate the mechanism of the transcriptional upregulation of the HIF‐1α gene, we have shown that Egr1 is able to directly bind to the HIF‐1α promoter using chromatin immunoprecipitation. We also provide evidence that the binding of Egr1 is necessary for the trans‐activation of the HIF‐1α promoter. These studies highlight the importance for the Egr1 transcription factor in the hypoxic response in cultured prostate cancer cell lines, and indicate that the response of Egr1 is upstream of HIF‐1 in these cells. These studies are the first demonstration that the HIF‐1α transcription factor is targeted directly by Egr1 in hypoxia. © 2008 Wiley‐Liss, Inc.
Monitoring and verifying cloud forecasts originating from operational numerical models
Authors: Zingerle Christoph , Nurmi Pertti
Published: May 2008

Weather satellites produce large amounts of observational data in real time. This information has high temporal and spatial resolution covering almost every region of the globe. The infrared (IR) window channels of operational meteorological satellites are sensitive to the clouds and to the underlying surface. Comparing the IR channel observations with synthetic satellite images is an effective way to evaluate the quality of cloud forecasts produced by numerical models. Assessment of potentially problematic features in the early stages of the forecast is essential in not only nowcasting and very short‐range forecasting but also in a reliability check of a given numerical weather prediction model (NWP). A pre‐operational real‐time monitoring system is set up in the Finnish Meteorological Institute, using the observed and synthetic satellite images, and applying an entity‐based verification method. Copyright © 2008 Royal Meteorological Society
A Comparison of Modeling Approaches for Dispersion Homopolymerization of MMA and Styrene in Supercritical CO2
Authors: Quintero‐Ortega Iraís A. , Jaramillo‐Soto Gabriel , García‐Morán Pedro R. , Castellanos‐Cárdenas M. Luz , Luna‐Bárcenas Gabriel , Vivaldo‐Lima Eduardo
Published: May 2008

A comparison of kinetic models for dispersion polymerization of MMA and styrene in supercritical CO2 is presented. The limiting case of solution polymerization, as a simplified case, was also addressed. Calculation of the partition of components between the continuous and dispersed phases was emphasized. Experimental data for the solution and dispersion polymerizations of styrene and MMA, using different types of stabilizers, were used to guide the study. Although all the models analyzed can be considered as “adequate” in representing the behavior of the system, some of their strengths and drawbacks have been highlighted.

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Changes in utilisation of hormone replacement therapy in Australia following publication of the findings of the Women's Health Initiative
Authors: Main Penelope , Robinson Maxine
Published: May 2008

Purpose

To examine the impact of publication of the findings of the Women's Health Initiative (WHI) on the utilisation of hormone replacement therapy (HRT) in Australia with particular reference to the influence that media may have had on prescriber and consumer behaviour.

Methods

Retrospective data from the Australian Government Department of Health, Ageing DUSC Database and media hits from Factiva were reviewed to obtain prescription numbers, total cost and cost to the pharmaceutical benefits scheme and number of media hits from the year before publication of the combined HRT arm of the WHI.

Results

Prescribing of HRT products decreased significantly immediately following publication of the combined HRT arm of the WHI and continued to decline at a slower rate following publication of the memory and oestrogen only arms of the study.

Conclusions

These results represent a more accurate national estimate of the change in HRT use in Australian women relative to previous findings from surveys carried out in Australia. Copyright © 2008 John Wiley & Sons, Ltd.
Complexation of niflumic acid with native and hydroxypropylated α‐ and β‐cyclodextrins in aqueous solution
Authors: Zielenkiewicz Wojciech , Terekhova Irina V. , Koźbiał Małgorzata , Wszelaka‐Rylik Małgorzata , Kumeev Roman S.
Published: May 2008

Interactions between niflumic acid and native and hydroxypropylated α‐ and β‐cyclodextrins (CDs) were investigated by 1H NMR, UV‐vis spectroscopy, densimetry, and calorimetry at pH = 7.4 (phosphate buffer) and T = 298.15 K. Thermodynamic parameters of 1:1 complex formation were calculated and discussed in terms of influence of cavity size and availability of hydroxypropyl substituents on the complex stability. The 1H NMR data indicated the inclusion of niflumic acid into macrocyclic cavity of all CDs under study. It was found that both phenyl and pyridine rings of niflumic acid molecule can be included in the cyclodextrin cavity. The co‐existence of two different kinds of 1:1 inclusion complexes in the solution was suggested. In spite of the fact that binding of niflumic acid with α‐cyclodextrin is more enthalpically favorable, stability of the inclusion complexes is very low due to the enthalpy–entropy compensation effect. Complex formation of β‐CDs with niflumic acid is characterized by the higher enthalpy and entropy changes caused by more intense dehydration. Introduction of hydroxypropyl groups in the cyclodextrin molecule was found to promote the binding with niflumic acid. Copyright © 2008 John Wiley & Sons, Ltd.
Frost weathering: recent advances and future directions
Authors: Matsuoka Norikazu , Murton Julian
Published: May 2008

This paper reviews frost‐weathering studies in the last five years and proposes key questions to be answered. New techniques have enabled us to monitor moisture contents and crack movements in near‐surface hard jointed bedrock and to evaluate seasonal rockfall activity in high mountains. Field monitoring has highlighted the roles of diurnal and annual frost cycles in controlling the timing and magnitude of frost weathering. In the laboratory, bidirectional freezing in soft, porous rocks has produced fractures containing segregated ice layers near the permafrost table, which imply the development of ice‐filled fractures in permafrost bedrock over long time‐scales. This finding, combined with numerical modelling of the thermal regime in permafrost rock slopes, contributes to the prediction of large‐scale rockfalls and rock avalanches triggered by permafrost degradation. Future studies should also focus on explosive shattering, frost weathering of hard‐intact rocks, field monitoring of ice segregation and bedrock heave, and the role of frost weathering in landscape evolution. Copyright © 2008 John Wiley & Sons, Ltd.
Buprofezin susceptibility survey, resistance selection and preliminary determination of the resistance mechanism in Nilaparvata lugens (Homoptera: Delphacidae)
Authors: Wang Yanhua , Gao Congfen , Xu Zhiping , Zhu Yu Cheng , Zhang Jiushuang , Li Wenhong , Dai Dejiang , Lin Youwei , Zhou Weijun , Shen Jinliang
Published: May 2008

BACKGROUND: Buprofezin has been used for many years to control Nilaparvata lugens (Stål). Assessment of susceptibility change in the insect is essential for maintaining control efficiency and resistance management.

RESULTS: Eleven‐year surveys showed that most field populations were susceptible before 2004. However, substantially higher levels of resistance (up to 28‐fold) were found in most of the rice fields in China after 2004. A field population was collected and periodically selected for buprofezin resistance in the laboratory. After 65 generations (56 were selected), the colony successfully obtained 3599‐fold resistance to buprofezin. Synergism tests showed that O,O‐diethyl‐O‐phenyl phosphorothioate (SV1), piperonyl butoxide (PBO) and diethyl maleate (DEM) increased buprofezin toxicity in the resistant strain by only 1.5–1.6 fold, suggesting that esterases, P450‐monooxygenases and glutathione S‐transferases had no substantial effect on buprofezin resistance development.

CONCLUSION: The results from this study indicate that N. lugens has the potential to develop high resistance to buprofezin. A resistance management program with rotation of buprofezin and other pesticides may efficiently delay or slow down resistance development in the insect. Further investigation is also necessary to understand the resistance mechanisms in N. lugens. Copyright © 2008 Society of Chemical Industry
Residues of 14C‐metsulfuron‐methyl in Chinese paddy soils
Authors: Wang Haizhen , Wu Jianjun , Yates Scott , Gan Jay
Published: May 2008

BACKGROUND: Metsulfuron‐methyl is widely used for controlling many annual grasses and broadleaf weeds in cereal crops. Nonetheless, increasing evidence has demonstrated that even extremely low levels of metsulfuron‐methyl residues in soil can be toxic to subsequent crops or non‐target organisms. The behavior of herbicides in soils is mostly related to their residual forms. The intent of the present study was to investigate the dynamics of extractable residues (ERs) and non‐extractable residues (NERs) of 14C‐metsulfuron‐methyl in twelve Chinese paddy soils and their relationships to soil properties.

RESULTS: ERs decreased gradually after application, whereas NERs increased rapidly during the initial 28 days, and gradually decreased thereafter. ERs and NERs were respectively 10.1–67.9% and 5.6–28.7% of applied radioactivity in soils at 224 days after application. ERs correlated positively with soil pH and silt fractions, and negatively with microbial biomass carbon (MBC) and clay fractions, but the opposite was observed for NERs.

CONCLUSION: Both ERs and NERs may be present in the soil at the time of planting following rice crops, and the risk of phytotoxic effects needs to be considered. Soil pH, MBC and clay/silt fractions were the main factors in affecting the amounts of both ERs and NERs of metsulfuron‐methyl in the tested soils. Copyright © 2008 Society of Chemical Industry
Elastic and inelastic tunneling through one‐electron and two‐electron states in a vertical double quantum dot
Authors: Kodera T. , Ono K. , Amaha S. , Tokura Y. , Arakawa Y. , Tarucha S.
Published: May 2008

We study the magnetic field dependence of tunnelling current through the two triplet states as well as the two single‐particle states in a double quantum dot. The single‐particle state tunnelling occurs between a discrete state and three nearly degenerate states. The resonance current shows a large variation for the three states at zero‐field, and becomes equivalent as the field increases to lift the degeneracy. This can be assigned to coherent mixing of the degenerate states. The other tunnelling occurs between a triplet having one electron in each dot and that having two electrons in one of the two dots. The resonance width is much smaller than that for the single‐particle tunnelling at zero‐field, and gradually increases as the field increases. This reflects that conservation of the spin z‐component is crucial for the inter‐dot tunnelling. Particularly in the small field range, the resonance can be significantly disturbed by fluctuating nuclear spin field. For the triplet state tunnelling, we also observe gradual increase of inelastic current with phonon emission as the field increases. This is consistent with theory of electron‐phonon scattering whose contribution increases as the inter‐dot tunnel coupling increases. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of spontaneous and piezoelectric polarizations on carrier confinement at the Zn0.88Mn0.12O/ZnO interface
Authors: Masuko K. , Sakiyama H. , Ashida A. , Yoshimura T. , Fujimura N.
Published: May 2008

For Zn1‐x Mnx O/ZnO heterostructures pseudomorphically grown on ZnO (000$ \bar 1 $) single‐crystal substrates, spontaneous and piezoelectric polarization‐induced sheet charges were investigated. The sheet carrier concentration of a Zn0.88Mn0.12O/ZnO heterostructure with a 10‐nm‐thick ZnMnO spacer layer was determined to be 5.6×1012 cm–2 by Hall measurement. For x = 0.12, the number of free electrons induced by spontaneous and piezoelectric polarizations was calculated to be 1.8×1012 cm–2, which is less than the experimental value. This discrepancy can be explained by considering an additional electric field generated by the ZnMnO/ZnO conduction band offset and ZnMnO spacer layer. Therefore, for ZnMnO/ZnO heterostructures, the effect of electric field should also be considered together with spontaneous and piezoelectric polarizations in carrier confinement. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wet chemical etching behavior of β‐Ga2O3 single crystal
Authors: Ohira Shigeo , Arai Naoki
Published: May 2008

Wet chemical etching behavior of β‐Ga2O3 single crystal was investigated to evaluate its chemical stability and to explore etchants for β‐Ga2O3 single crystal. Undoped and Sn‐doped β‐Ga2O3 single crystals were grown by the floating zone method, and (100)‐ and (001)‐oriented samples were chemical‐mechanical‐polished to wafers. The samples were wet chemically etched in solutions such as HCl, H2SO4, HNO3, HF, H2O2:H2SO4:H2O=1:4:1, KOH, and NaOH. The samples were chemically stable against both acids and alkalis except HF and NaOH. Aqueous HF solution was found to etch β‐Ga2O3 uniformly at room temperature. The etch rate increased with increasing immersion time and HF content. Anisotropy of etch rate was observed between the (100) and (001) planes. The etch rate of Sn‐doped β‐Ga2O3 was lower than that of undoped β‐Ga2O3, and the etch rate decreased with increasing Sn doping content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical anisotropy of strained quantum wells on high index substrates
Authors: Niki Nobuyoshi , Morita Ken , Kitada Takahiro , Isu Toshiro
Published: May 2008

We investigate anisotropic properties of strained InGaAs quantum wells on the high index (11n)A (n = 3,4,5) GaAs substrates. The polarization dependence of photoluminescence of strained InGaAs quantum wells were measured, and optical anisotropy was observed. We calculated anisotropy of the optical transition matrix elements based on the 4x4 and 6x6 Luttinger model for the quantum wells with uniaxial strain. The calculated anisotropy taking into account of split‐off band qualitaively agree with our experiment. This indicates that the band mixing of split‐off band into the heavy‐hole band largely contributes to the the optical anisotropy in the strained InGaAs quantum wells on the high index substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reduction of self‐heating in AlGaN/GaN HFETs using thick AlN surface passivation films
Authors: Tanaka N. , Takita H. , Sumida Y. , Suzuki T.
Published: May 2008

We have fabricated and investigated AlGaN/GaN heterojunction field‐effect transistors (HFETs) with thick AlN surface passivation films. The HFETs exhibit increased drain currents and the transconductances with suppression of the self‐heating‐induced negative differential conductance at high applied voltages. Since the effects are more prominent for thicker AlN films, we conclude that the AlN films cause not only surface passivation, but also self‐heating reduction. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of thick ZnO films by metal‐source vapor phase epitaxy
Authors: Duan Yao , Cui Junpeng , Wang Xiaofeng , Zeng Yiping
Published: May 2008

Metal‐Source Vapor Phase Epitaxy (MVPE), which takes advantage of the reaction of Zn vapor and H2O vapor at high temperature, was employed to grow thick epitaxial ZnO films on c‐sapphire substrates. This method exhibits high growth rate (>120μm/h), good crystallinity and thickness uniformity. A re‐growth method is used to control the polarity of ZnO films and both Zn‐polar and O‐polar samples are obtained. The structural and electric properties and morphology of the samples were characterized by X‐ray diffraction (XRD), Hall measurements and scanning electron microscope (SEM), respectively. The samples' polarities were identified by wet etching method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement in crystalline quality of thick GaInN on m‐plane 6H‐SiC substrates using sidewall epitaxial lateral overgrowth
Authors: Senda Ryota , Miura Aya , Kawashima Takeshi , Iida Daisuke , Nagai Tetsuya , Iwaya Motoaki , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu
Published: May 2008

We report the fabrication of an epitaxial lateral overgrown (ELO) GaInN layer on a high crystalline‐quality‐grooved GaN template, which is improved by a sidewall ELO (SELO) technology. The photoluminescence peak intensity of ELO‐grown GaInN layer on the SELO GaN underlying layer is twice as high as that of ELO‐grown GaInN layer on the m‐plane GaN template. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
706‐GHz GaAs CW fundamental‐mode TUNNETT diodes fabricated with molecular layer epitaxy
Authors: Nishizawa J. , Płotka P. , Kurabayashi T. , Makabe H.
Published: May 2008

GaAs TUNNET diodes with 75‐nm thick undoped transit‐time layer and 14‐nm thick n+ electric‐field‐inducing layer, fabricated with molecular layer epitaxy, were oscillating in fundamental‐mode, metal, rectangular WR‐1.0 (0.254 × 0.127 mm) resonant cavities at 706 GHz. The continuous wave output power was ‐67 dBm, at the bias current of 600 mA. The frequency range of continuous wave fundamental‐mode TUNNETT diodes fabricated with molecular layer epitaxy extends from 60 GHz (+13 dBm) to 706 GHz. Modulation experiments of lower frequency, 86‐GHz and 163‐GHz, TUNNETTs have shown that TUNNETTs are suitable for broadband communication and other systems at the modulation rate exceeding 2 Gbps. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetotransport through a two‐dimensional hole antidot lattice: Signatures of Berry phase
Authors: Kang Ning , Abe Eisuke , Hashimoto Yoshiaki , Iye Yasuhiro , Katsumoto Shingo
Published: May 2008

We study the low‐field magnetotransport of a twodimensional hole antidot lattice subject to strong spinorbit interaction. The Aharonov‐Bohm type oscillations appearing in the low‐temperature magnetoresistance have components corresponding to h /e and h /2e. We interpret the nodes seen in the h /e oscillations as signatures of the spin‐orbit Berry phase, based on a simple simulation taking into account its contribution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scale‐dependent verification of ensemble forecasts
Authors: Jung Thomas , Leutbecher Martin
Published: May 2008

A scale‐dependent verification of the ECMWF ensemble prediction system (EPS) in the Northern Hemisphere is presented. The relationship between spread and skill is investigated alongside probabilistic forecast skill for planetary, synoptic and subsynoptic spectral bands. Since the ECMWF model is a spectral model, the three spectral bands have been isolated using total and zonal wavenumber filters. Diagnosed overdispersiveness of ECMWF EPS in the short range is primarily due to excessive amounts of spread on synoptic scales. Diagnosed underdispersiveness of the ensemble beyond day 5 of the forecast can be explained by too little spread on both synoptic and planetary scales. Copyright © 2008 Royal Meteorological Society
Conditional nonlinear optimal perturbation of a T21L3 quasi‐geostrophic model
Authors: Jiang Zhina , Mu Mu , Wang Donghai
Published: May 2008

Conditional nonlinear optimal perturbation (CNOP) is defined as an initial perturbation that makes the cost function attain the maximum at a prescribed forecast time with physical constraint conditions, which is a natural generalization of the linear singular vector (LSV) into the nonlinear regime. In this paper, CNOPs of a T21L3 quasi‐geostrophic (QG) spectral model in three kinds of norms are obtained numerically by solving nonlinear optimization problems, and further compared with their linear counterparts, namely LSVs.

Results reveal that CNOPs do depend, as LSVs do, on the norm chosen. The stream‐function‐squared norm yields small‐scale disturbances; the results obtained by total‐energy norm are characterized by intermediate‐scale disturbances; and in the case of the enstrophy norm, CNOPs are typified by large‐scale disturbances with large zonal flow contribution. If the linear approximation is valid, CNOP shows great resemblance to LSV, both of which are much localized in cases of the stream‐function‐squared and total‐energy norms. However, with the increasing of the optimization time interval and/or the magnitude of the initial constraint condition, CNOP has less localized structures than the corresponding LSV in these two norms. What is more, the wave train structures of CNOP may even be found in the whole zonal direction in the Northern Hemisphere. The evolutions of perturbations, represented by CNOPs and LSVs in the total‐energy norm, are also investigated in detail. The similarities and dissimilarities between CNOPs and LSVs are revealed not only from the growth rate but also from the similarity index of spatial patterns.

The numerical results imply that the method of CNOP may be a more appropriate tool for the study of stability and sensitivity problems when nonlinearity is of importance. Furthermore, the proper norm should be chosen for different physical problems. Copyright © 2008 Royal Meteorological Society
Observations of cross‐ridge flows across steep terrain
Authors: Lewis H. W. , Mobbs S. D. , Lehning M.
Published: May 2008

A field experiment, Gaudex, has been conducted to address the need for quantitative measurements of turbulence in the vicinity of steep terrain. A dense network of automatic weather stations and turbulence towers was deployed along cross‐ridge transects over Gaudergrat, a steep triangular cross‐section ridge in eastern Switzerland.

A new feature, whereby ridge‐normal cross‐ridge flows develop at the crest even when the flow in each valley is oriented parallel to the ridge axis, is identified. This occurs independently of whether the flow is thermally or synoptically driven. Pressure measurements across the ridge show that this flow is driven by a cross‐ridge pressure gradient. Two mechanisms for generating cross‐ridge flows have been identified from measurements of pressure, wind and temperature. In most cases the pressure gradient arises from a difference in flow speeds between the two sides of the ridge, caused by different valley geometries. Less commonly, the cross‐ridge flow is explained by linear speed‐up of the ridge‐normal flow. Copyright © 2008 Royal Meteorological Society
Coupled‐cluster approach to spontaneous symmetry breaking in molecules: The linear N3 radical
Authors: Li Xiangzhu , Paldus Josef
Published: May 2008

Symmetry‐breaking phenomena that often affect calculation of potentials for the linear ABA species along the antisymmetric‐stretching coordinate are examined for the case of the ground state of the N3 radical using various coupled‐cluster methods and molecular orbitals. The difficulties that are encountered when employing UHF‐type approaches are found to be particularly striking. It is shown that the inconsistencies that arise when relying on a numerical differentiation can be overcome by exploiting the computed potentials in the Schrödinger equation for the nuclear motion. This approach yields reliable values for the vibrational levels even in the presence of singularities that plague the UHF‐based potentials. The variety of the symmetry‐breaking phenomena that occur for these systems, including the notoriously intricate BNB radical, are briefly discussed. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Sampling independent sets in the discrete torus
Authors: Galvin David
Published: May 2008

The even discrete torus is the graphTL,don vertex set {0,…,L– 1}d(withLeven) in which two vertices are adjacent if they differ on exactly one coordinate and differ by 1(modL) on that coordinate. The hard‐core measure with activity λ onTL,dis the probability distribution πλon the independent sets (sets of vertices spanning no edges) ofTL,din which an independent setIis chosen with probability proportional to λ|I|. This distribution occurs naturally in problems from statistical physics and the study of communication networks.

We study Glauber dynamics, a single‐site update Markov chain on the set of independent sets ofTL,dwhose stationary distribution isπλ. We show that for λ = ω(d−1/4log3/4d) anddsufficiently large the convergence to stationarity is (essentially) exponentially slow inLd−1. This improves a result of Borgs, Chayes, Frieze, Kim, Tetali, Vigoda, and Vu (Proceedings of the IEEE FOCS (1999), 218–229)5who had shown slow mixing of Glauber dynamics for λ growing exponentially withd.

Our proof, which extends to ρ‐local chains (chains which alter the state of at most a proportion ρ of the vertices in each step) for suitable ρ, closely follows the conductance argument of Borgs et al.,5adding to it some combinatorial enumeration methods that are modifications of those used by Galvin and Kahn (Combinatorics, Probability and Computing 13 (2004), 137–164)12to show that the hard‐core model with parameter λ on the integer lattice ℤdexhibits phase coexistence for λ =ω(d−1/4log3/4d).

The discrete even torus is a bipartite graph, with partition classes ε (consisting of those vertices the sum of whose coordinates is even) and$$ \cal{O} $$. Our result can be expressed combinatorially as the statement that for each sufficiently large λ, there is a ρ(λ) > 0 such that ifIis an independent set chosen according toπλ, then the probability that ‖I∩ε|—|I∩$ \cal{O} $‖ is at most ρ(λ)Ldis exponentially small inLd−1. In particular, we obtain the combinatorial result that for all ε > 0 the probability that a uniformly chosen independent set fromTL,dsatisfies ‖I∩ε|—|I∩$ \cal{O} $‖≤ (.25 ‐ε)Ldis exponentially small inLd−1. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008
From the horse's mouth: What scientists say about scientific investigation and scientific knowledge
Authors: Wong Siu Ling , Hodson Derek
Published: May 2008

This study sought to identify prominent features of the nature of science (NOS) embedded in authentic scientific inquiry. Thirteen well‐established scientists from different parts of the world, working in experimental or theoretical research, in both traditional fields such as astrophysics and rapidly growing research fields such as molecular biology, completed an open‐ended questionnaire about the NOS and participated in in‐depth interviews. The descriptions of their practices provide a somewhat striking contrast to the image of science usually portrayed in science curricula and textbooks. These accounts of authentic scientific practice have considerable potential for development into interesting cases as teaching resources to enhance and enrich students' understanding of NOS and for the design of more effective laboratory work and field experience. © 2008 Wiley Periodicals, Inc. Sci Ed 93:109–130, 2009
Erratum: Shareholder valuation of foreign investment and expansion. Heather Berry. Strategic Management Journal, 27(12): 1123–1140 (2006)
Authors: Berry Heather
Published: May 2008

Half of the last sentence in the abstract was incorrectly deleted in the original publication of this
paper. The sentence should read as follows:

"These results highlight the importance of considering firm location decisions, prior experiences and resources when analyzing the performance effects from multinationality by showing that shareholders value different paths to international expansion for firms that vary in these dimensions."
Serotoninergic dorsal raphe neurons possess functional postsynaptic nicotinic acetylcholine receptors
Authors: Galindo‐Charles Luis , Hernandez‐Lopez Salvador , Galarraga Elvira , Tapia Dagoberto , Bargas José , Garduño Julieta , Frías‐Dominguez Carmen , Drucker‐Colin René , Mihailescu Stefan
Published: May 2008

Very few neurons in the telencephalon have been shown to express functional postsynaptic nicotinic acetylcholine receptors (nAChRs), among them, the noradrenergic and dopaminergic neurons. However, there is no evidence for postsynaptic nAChRs on serotonergic neurons. In this study, we asked if functional nAChRs are present in serotonergic (5‐HT) and nonserotonergic (non‐5‐HT) neurons of the dorsal raphe nucleus (DRN). In rat midbrain slices, field stimulation at the tegmental pedunculopontine (PPT) nucleus evoked postsynaptic currents (eEPSCs) with different components in DRN neurons. After blocking the glutamatergic and GABAergic components, the remaining eEPSCs were blocked by mecamylamine and reduced by either the selective α7 nAChR antagonist methyllycaconitine (MLA) or the selective α4β2 nAChR antagonist dihydro‐β‐eritroidine (DHβE). Simultaneous addition of MLA and DHβE blocked all eEPSCs. Integrity of the PPT‐DRN pathway was assessed by both anterograde biocytin tracing and antidromic stimulation from the DRN. Inward currents evoked by the direct application of acetylcholine (ACh), in the presence of atropine and tetrodotoxin, consisted of two kinetically different currents: one was blocked by MLA and the other by DHβE; in both 5‐HT and non‐5‐HT DR neurons. Analysis of spontaneous (sEPSCs) and evoked (eEPSCs) synaptic events led to the conclusion that nAChRs were located at the postsynaptic membrane. The possible implications of these newly described nAChRs in various physiological processes and behavioral events, such as the wake‐sleep cycle, are discussed. Synapse 62:601–615, 2008. © 2008 Wiley‐Liss, Inc.
The value of umbilical artery Doppler velocimetry in the antenatal surveillance of uncomplicated monochorionic twin pregnancies
Authors: Hack K. E. A. , Kaandorp J. J. , Derks J. B. , Elias S. G. , Pistorius L. , Visser G. H. A.
Published: May 2008

Objectives

To investigate the predictive value of abnormal umbilical artery Doppler findings on outcome in uncomplicated monochorionic (MC) twin pregnancies.

Methods

Sixty‐seven MC twin pregnancies, with antenatal care and delivery at the University Medical Center, Utrecht, The Netherlands, between 1999 and 2004, were studied. Pregnancies with antenatal signs of twin‐to‐twin transfusion syndrome were excluded. We analyzed the data according to both the last Doppler measurement of the umbilical artery before delivery and the presence of any abnormal Doppler measurement during the course of pregnancy. Risks of mortality and total neonatal morbidity were stratified according to the Doppler findings in one or both fetuses at the time of each standard ultrasound assessment in order to estimate the risk associated with an abnormal Doppler finding at or before that specific gestational age.

Results

Mortality rates were similar in the normal and abnormal Doppler groups. Using both group definitions, total neonatal morbidity was higher in the abnormal Doppler group; this was significant at > 32 weeks' gestation, and was due to lower birth weight and earlier gestational age at delivery. There was no mortality at ≥ 36 weeks in the abnormal Doppler group, but there were four perinatal deaths in the normal Doppler group. Gestational age at delivery was significantly lower when one or more abnormal Doppler findings had been present (median, 34 + 1 weeks vs. 36 + 3 weeks) and infants with abnormal Doppler findings weighed on average 261 g (95% CI, 21–502g) less than those with normal findings.

Conclusions

In MC twins, abnormal Doppler flow of the umbilical artery identifies a subgroup at risk for preterm delivery, low birth weight and neonatal morbidity, but with a similar mortality risk to those with normal Doppler flow. At term, mortality occurred only in the group with normal Doppler findings, suggesting that fetal surveillance is insufficient in uncomplicated term MC twin pregnancies. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal assessment of the normal fetal soft palate by three‐dimensional ultrasound examination: is there an objective technique?
Authors: Faure J.‐M. , Bäumler M. , Boulot P. , Bigorre M. , Captier G.
Published: May 2008

Objectives

To describe a three‐dimensional (3D) ultrasound technique for assessing the fetal soft palate.

Methods

A prospective study conducted from April to December 2006 included 87 fetuses in a low‐risk population. Fetal ultrasound scans were performed between 21 and 25 weeks of gestation to determine the normal 3D ultrasound view of the fetal soft tissues of the palate. The sonographers used a 30°‐inclined axial 3D view of the fetal palate. Ultrasound images obtained in this view were compared with fetopathological specimens of the same gestational age by two observers, both pediatric surgeons. Each observer indicated whether they thought that the uvula or the velum could be detected, and the differences in responses between the observers were assessed.

Results

The frequencies of detection of the uvula and velum of each observer varied between 80% and 90%. The observers showed a significant difference in judging the visualization of the uvula, but not in judging the velum.

Conclusions

A 30°‐inclined axial 3D ultrasound view seems to be effective in assessing the integrity of the fetal soft palate. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Quantitative elemental analysis of FeZn‐alloy coating by nondestructive method
Authors: Park Hyoungkuk , Lee Chong Soo
Published: May 2008

A quantitative analytical method of iron content in FeZn‐alloy coating by x‐ray diffraction (XRD) spectrum was proposed. This work aimed to replace the wet chemical analysis of FeZn‐alloy coating with rapid and reproducible quantification by an XRD spectrum. Partial least‐squares (PLS) model was utilized to differentiate the spectral characteristic as well as to quantify each component in XRD spectrum. Fifteen standard samples were prepared by heat treatment and verified by the relationship between wet chemical analyses and the XRD spectrum for iron content. The suggested method showed satisfactory precision and accuracy in the analysis of FeZn‐alloy coating. The accuracy for iron content in FeZn‐alloy coating was 0.17 wt%. Copyright © 2008 John Wiley & Sons, Ltd.
Delayed union of an operated fracture of the femoral neck
Authors: Dhar Shabir Ahmed , Gani Naseem U. , Butt Mohammed F. , Farooq Munir , Mir Mohammed Ramzan
Published: May 2008

Fracture of the femoral neck continues to be a vexing clinical and therapeutic challenge for the orthopedic surgeon. The fracture has a propensity for non-union and avascular necrosis. It is a challenge for the orthopedic surgeon to decide when to intervene in a case with non-union where the implant continues to be in place. We present a case with persistent clinical and radiological non-union signs where the fracture eventually united after 32 months. The case bolsters the view that a continued conservative regime might entail good results in such situations.
Monogenetische Risikofaktoren einer Thrombophilie
Authors: Pavlova A. , Hertfelder H.-J.
Published: May 2008

Die hereditären Thrombophilien gehören zu den angeborenen Prädispositionen, die thrombotische Ereignisse begünstigen. Die wichtigsten monogenetischen Ursachen für einen venös-thromboembolischen (VTE) Phänotyp stellen Mutationen innerhalb der Gene für die Inhibitoren Antithrombin (AT), Protein C (PC) und Protein S (PS) dar. Die Mutationsprofile in diesen Genen sind sehr unterschiedlich. Die Frequenz von AT-, PC- und PS-Mängeln wird bei VTE-Patienten jeweils mit 1,9%, 2,3% und 3,7% angegeben. Die VTE-Rezidivrate liegt in dieser Gruppe bei etwa 48%. Sie ist für AT-, PC- und PS-Mängel zusammengefasst 1,5-fach, für den AT-Mangel isoliert betrachtet 1,9-fach höher als bei VTE-Patienten ohne einen dieser Mängel. Die Detektionsrate bei einem Inhibitormangel und VTE-Ereignis liegt bei etwa 70% für AT, bei 60% für PC und bei 30% für PS. Dies unterstreicht das Problem der unterschiedlichen Sicherheit der Diagnose der Phänotypen und der damit zusammenhängenden differentialdiagnostischen Abgrenzung zwischen erworbenem und angeborenem Inhibitormangel.
Flavonoids: modulators of brain function?
Authors: Spencer Jeremy P. E.
Published: May 2008

Emerging evidence suggests that dietary phytochemicals, in particular flavonoids, may exert beneficial effects on the central nervous system by protecting neurons against stress-induced injury, by suppressing neuroinflammation and by improving cognitive function. It is likely that flavonoids exert such effects, through selective actions on different components of a number of protein kinase and lipid kinase signalling cascades, such as the phosphatidylinositol-3 kinase (PI3K)/Akt, protein kinase C and mitogen-activated protein kinase (MAPK) pathways. This review explores the potential inhibitory or stimulatory actions of flavonoids within these pathways, and describes how such interactions are likely to underlie neurological effects through their ability to affect the activation state of target molecules and/or by modulating gene expression. Future research directions are outlined in relation to the precise site(s) of action of flavonoids within signalling pathways and the sequence of events that allow them to regulate neuronal function.
Antioxidant phytochemicals against type 2 diabetes
Authors: Dembinska-Kiec Aldona , Mykkänen Otto , Kiec-Wilk Beata , Mykkänen Hannu
Published: May 2008

Dietary phytochemicals, of which polyphenols form a considerable part, may affect the risk of obesity-associated chronic diseases such as type 2 diabetes. This article presents an overview on how phytochemicals, especially polyphenols in fruits, vegetables, berries, beverages and herbal medicines, may modify imbalanced lipid and glucose homeostasis thereby reducing the risk of the metabolic syndrome and type 2 diabetes complications.
TRANSIENT BEHAVIOR OF PROCESSES IN THE TCP PARADIGM
Authors: Ott T. J. , Kemperman J. H. B.
Published: May 2008

This article derives the transient behavior of the stochastic process X(t) for which in earlier articles it was proven that for α<1, the process (X(t))1/(1−α) (approximately, under low drop probability or ECN marking probability) describes the behavior of the congestion windows in certain transport protocols in the so-called TCP paradigm. The transient distribution is found explicitly and is particularly transparent for moments like E[(X(t))k |X(0)]. The purpose of this article is to be part of the mathematical foundation when comparing the many protocols in the TCP paradigm.
Intake of B vitamins in childhood and adult life in relation to psychological distress among women in a British birth cohort
Authors: Mishra Gita D , McNaughton Sarah A , O’Connell Maria A , Prynne Celia J , Kuh Diana
Published: May 2008

Background

Lower levels of B vitamins (particularly folate, vitamin B12and vitamin B6) may be associated with psychological distress. Little is known about the impact of childhood nutrition on psychological distress in adult life.

Objective

We investigated whether prospectively measured childhood and adult dietary intakes of thiamin, riboflavin, niacin, folate, vitamin B6and vitamin B12were related to the psychological distress of women in mid-age, taking into account socio-economic, behavioural and lifestyle factors.

Design

Prospective data were collected from a cohort of 636 British women followed up since their birth in 1946. Participants completed a 28-item, scaled version of the General Health Questionnaire (GHQ-28) to measure psychological distress at age 53 years. Dietary intakes in childhood (at age four) were determined by 24h recall and in adulthood (at age 36, 43 and 53 years) by a 5d food record.

Results

Low dietary vitamin B12intake at age 53 was associated with higher psychological distress at that age. Women in the lowest third of vitamin B12intake in adulthood had a higher GHQ-28 score compared with those in the highest third (percentage change, adjusted regression coefficient, 21 (95% CI 3, 39)). There were no other significant associations between dietary B vitamin intake in childhood or adulthood and psychological distress in the cohort.

Conclusions

Overall, there is evidence that intake of vitamin B12at age 53 is related to adult psychological distress but there is no evidence for the effects of other adult B vitamin intakes or childhood intakes on psychological distress.
Longitudinal growth of infants born to HIV-1-infected mothers in Belo Horizonte, Brazil
Authors: Fausto Maria Arlene , Carneiro Mariângela , Antunes Carlos Maurício F , Colosimo Enrico Antônio , Pinto Jorge A
Published: May 2008

Objective

To prospectively evaluate growth parameters assessed by weight and length in infected and uninfected infants born to HIV-1-infected mothers and followed from birth to 18 months.

Methods

A cohort consisting of ninety-seven uninfected and forty-two infected infants born to HIV-infected mothers enrolled from 1995 to 2004, and admitted during their first 3 months of life at a referral Pediatric AIDS Clinic in Belo Horizonte, Brazil. Infants were followed until 18 months of age. Data were analysed using mixed-effects linear regression models for weight and length fitted by restricted maximum likelihood.

Results

Infected infants contributed to 466 weight and 411 recumbent length measurements. Uninfected infants provided 924 weight and 907 length measurements. Mean birth weight and length were similar in both groups, 3·1 (sd 0·4) and 3·0 (sd 0·5) kg, and 48·7 (sd 1·4) and 48·8 (sd 2·9) cm for uninfected and infected infants, respectively. However, HIV-1 infection had an early impact in growth impairment: at 6 months of age, HIV-infected children were 1 kg lighter and 2 cm shorter than the uninfected.

Conclusions

Growth faltering in weight, but not length, in HIV-infected children in Brazil is more marked than that reported in a European cohort, probably reflecting background nutritional deficiencies and concomitant infections. In these settings, early and aggressive nutritional management in HIV-1-infected infants should be a priority intervention associated with the antiretroviral therapy.