bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of the Interface Between Electron‐Hole and Electron‐Ion Plasmas: Hybrid Semiconductor‐Gas Phase Devices as a Gateway for Plasma Science
Authors: Tchertchian P. A. , Wagner C. J. , Houlahan T. J. , Li B. , Sievers D. J. , Eden J. G.
Published: October 2011

Coupling electron‐hole (e–‐ h+) and electron‐ion plasmas across a narrow potential barrier with a strong electric field provides an interface between the two plasma genres and a pathway to electronic and photonic device functionality. The magnitude of the electric field present in the sheath of a low temperature, nonequilibrium microplasma is sufficient to influence the band structure of a semiconductor region in immediate proximity to the solid‐gas phase interface. Optoelectronic devices demonstrated by leveraging this interaction are described here. A hybrid microplasma/semiconductor photodetector, having a Si cathode in the form of an inverted square pyramid encompassing a neon microplasma, exhibits a photosensitivity in the ∼420–1100 nm region as high as 3.5 A/W. Direct tunneling of electrons into the collector and the Auger neutralization of ions arriving at the Si surface appear to be facilitated by an n ‐type inversion layer at the cathode surface resulting from bandbending by the microplasma sheath electric field. Recently, an npn plasma bipolar junction transistor (PBJT), in which a low temperature plasma serves as the collector in an otherwise Si device, has also been demonstrated. Having a measured small signal current gain hfe as large as 10, this phototransistor is capable of modulat‐ing and extinguishing the collector plasma with emitter‐base bias voltages <1 V. Electrons injected into the base when the emitter‐base junction is forward‐biased serve primarily to replace conduction band electrons lost to the collector plasma by secondary emission and ion‐enhanced field emission in which ions arriving at the base‐collector junction deform the electrostatic potential near the base surface, narrowing the potential barrier and thereby facilitating the tunneling of electrons into the collector. Of greatest significance, therefore, are the implications of active, plasma/solid state interfaces as a new frontier for plasma science. Specifically, the PBJT provides the first opportunity to control the electronic properties of a material at the boundary of, and interacting with, a plasma. By specifying the relative number densities of free (conduction band) and bound (valence band) electrons at the base‐collector interface, the PBJT's emitter‐base junction is able to dictate the rates of secondary electron emission (including Auger neutralization) at the semiconductor‐plasma interface, thereby offering the ability to vary at will the effective secondary electron emission coefficient for the base surface (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formulating functional foods with long‐chain polyunsaturated fatty acids: Challenges and opportunities
Authors: Destaillats Frédéric
Published: October 2011

The development of functional foods and supplements containing bioactive lipids, such as esters of long‐chain PUFA (LC‐PUFA), is very challenging. Although the requirements and nutritional value of LC‐PUFA are widely recognized, their physical and chemical characteristics are limiting the choice of product applications, packaging materials, processing, and shelf‐life conditions. In this issue of the European Journal of Lipid Science and Technology, Borhaug et al. report a new technology to produce water soluble concentrate of LC‐PUFA. Opportunities and challenges for this new generation of ingredients are discussed in the present commentary.

See accompanying article by Borhaug et al. on pages 1235–1242
Enantioselective Total Synthesis of (+)‐Hagen's Gland Lactones
Authors: Gharpure Santosh J. , Nanda Laxmi Narayan , Shukla Manoj Kumar
Published: October 2011

Enantioselective synthesis of Hagen's gland lactone is described. The enantiomerically enriched diol was prepared by organocatalytic α‐oxidation of the aldehyde. The other key reactions involved a highly diastereoselective intramolecular cyclopropanation of vinylogous carbonates to furnish donor–acceptor‐substituted cyclopropanes and their ring opening and iodolactonization followed by reduction.
Picomole Level Determination of Cholesterol by HPLC with Electrochemical Detection Using Boron‐doped Diamond Electrode after Performance Assessment Based on the FUMI Theory
Authors: Kotani Akira , Hakamata Hideki , Nakayama Nobuyuki , Kusu Fumiyo
Published: October 2011

For the performance assessment of an electrochemical flow cell using a boron‐doped diamond (BDD) electrode in high‐performance liquid chromatography with electrochemical detection (HPLC‐ECD) to determine cholesterol, the standard deviation (SD) of area measurements in chromatographic baseline noise (AMCBN) was evaluated based on the function of mutual information (FUMI) theory without repetitive chromatographic measurements. After the selection of suitable components for the electrochemical flow cell in HPLC‐ECD, the detection limit of cholesterol was 0.04 pmol at a detection potential of +2.2 V vs. an Ag/AgCl electrode. The present HPLC‐ECD was applied to determine cholesterol in various meats.
Synthesis and Electrochemical Characterization of Poly(2‐methoxy‐4‐vinylphenol) with MWCNTs
Authors: Corrêa Cátia Crispilho , Santhiago Murilo , de Carvalho Castro e Silva Cecília , Barboza Formiga André Luiz , Kubota Lauro Tatsuo
Published: October 2011

The present work describes a simple grafting of poly‐2‐methoxy‐4‐vinylphenol to multiwalled carbon nanotubes (MWCNTs) by in situ free radical polymerization. The synthesis was performed using mild conditions and the product (MWCNTs/pMVP) was stable for at least 6 months. Also, the dispersion of the MWCNTs/pMVP in dimethylformamide remained homogeneously distributed for up to 2 days, facilitating the modification of glassy carbon electrode. After an in situ activation process, the stable redox couple was formed (catechol/quinone) being able to electrocatalyze NADH oxidation at low overpotential with a high rate constant (kobs).
Plasma‐derived clotting factor VIII: Heterogeneity evaluation in the quest for potential inhibitory‐antibody stimulating factors
Authors: D'Amici Gian M. , Blasi Barbara , D'Alessandro Angelo , Vaglio Stefania , Zolla Lello
Published: October 2011

In this study, we investigated the heterogeneity and the purity grade of three commercially available plasma‐derived clotting factor VIII (FVIII) concentrates, which highly differ with regard to purification strategies, relative concentrations of stabilizers (von Willebrand factor, with or without albumin) and virus inactivation strategies (solvent/detergent and/or heat/pasteurization treatments). Western blot analyses were used to evaluate product‐specific variations from Emoclot®, Alphanate® and Haemate® both in the presence and absence of reducing agents (dithiotreithol). All the plasma‐derived concentrates showed a strong heterogeneity, as they all included a significant amount of truncated forms of the full‐length (FL) clotting FVIII protein. The intact protein accounted for the 38% of the total FVIII proteins in Haemate® and 29 and 23% in Alphanate® and Emoclot®, respectively. Lower intact FVIII amounts in Emoclot might be mainly due to the low von Willebrand factor dosage and the absence of albumin. Upon addition of thrombin, both the FL and truncated forms of the FVIII protein were almost completely digested. Indeed, after thrombin activation, we could still observe a mixture of B‐domain truncated forms of the FL protein along with biologically active digested‐A1 forms. Batch‐to‐batch variation was tested with no evident changes appearing among different batches. Despite the variables in manufacturing processes, inter‐product comparisons yielded similar results for all the plasma‐derived FVIII considered in this study. However, we could individuate in Emoclot a band that was not digested by thrombin, which we could characterize as the 200 kDa FVIII heavy chain. This investigation prompts new concerns about the strong heterogeneity observed upon thrombin digestion of plasma‐derived FVIII, which might contribute to the development of inhibitory antibodies at an early stage of therapy, and to which extent these untoward phenomena could be avoided through direct intervention on routine manufacturing processes.
Engineering of a novel pluronic F127/graphene nanohybrid for pH responsive drug delivery
Authors: Hu Haiqing , Yu Jinhai , Li Yongyong , Zhao Jian , Dong Haiqing
Published: October 2011

Herein, a novel Pluronic F127/graphene nanosheet (PF127/GN) hybrid was prepared via an one‐pot process including the simultaneous reduction of graphene oxide and assembly of PF127 and GN. The nanohybrid exhibits high water dispersibility and stability in physiological environment with the hydrophilic chains of PF127 extending to the solution while the hydrophobic segments anchoring at the surface of graphene via hydrophobic interaction. The PF127/GN nanohybrid is found to be capable of effectively encapsulating doxorubicin (DOX) with ultrahigh drug‐loading efficiency (DLE; 289%, w/w) and exhibits a pH responsive drug release behavior. The superb DLE of the PF127/GN nanohybrid relies on the introduction of GN which is structurally compatible with DOX. Cellular toxicity assays performed on human breast cancer MCF‐7 cells demonstrate that the PF127/GN nanohybrid displays no obvious cytotoxicity, whereas the PF127/GN‐loaded DOX (PF127/GN/DOX) shows remarkable cytotoxicity to the MCF‐7. Cell internalization study reveals that PF127/GN nanohybrid facilitates the transfer of DOX into MCF‐7 cells, evidenced by the image of confocal laser scanning microscopy. The above results indicate the potential application of this novel nanocarrier in biomedicine. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Azadirachta indica exhibits chemopreventive action against hepatic cancer: Studies on associated histopathological and ultrastructural changes
Authors: Bharati Sanjay , Rishi Praveen , Koul Ashwani
Published: October 2011

The present study was designed to evaluate the anticarcinogenic potential of Azadirachta indica against N‐nitrosodiethylamine (NDEA)‐induced hepatocarcinogenesis. Further, the associated histopathological and ultrastructural changes were also analyzed. Hepatic cancer model was developed by the intraperitoneal administration of NDEA to mice at weekly intervals, in successive increasing doses, for a period of 8 weeks. Aqueous A. indica leaf extract (AAILE) was administered orally at a dosage of 100 μg/g body weight thrice a week till termination of the study. A relationship between histopathological grading and chemopreventive effect of A. indica had been established at various stages of carcinogenesis. Anticancer activity of A. indica was evaluated in terms of tumor incidence, tumor multiplicity, and survival rate. A significant reduction in tumor incidence (33%), tumor multiplicity (42%), and increase in survival (34%) was observed upon administration of AAILE to NDEA‐abused mice. Transmission and scanning electron microscopic investigations showed severe alterations in organelle organization, cellular arrangement, degree of differentiation, cellular metabolism, and morphology of the hepatocytes. These changes appeared to be distinctly delayed upon AAILE supplementation. The results suggest A. indica may have anticancer potential against NDEA‐induced hepatic cancer. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.
Simultaneous electroencephalography‐functional MRI at 3 T: An analysis of safety risks imposed by performing anatomical reference scans with the EEG equipment in place
Authors: Nöth Ulrike , Laufs Helmut , Stoermer Robert , Deichmann Ralf
Published: October 2011

Purpose:

To describe heating effects to be expected in simultaneous electroencephalography (EEG) and magnetic resonance imaging (MRI) when deviating from the EEG manufacturer's instructions; to test which anatomical MRI sequences have a sufficiently low specific absorption rate (SAR) to be performed with the EEG equipment in place; and to suggest precautions to reduce the risk of heating.

Materials and Methods:

Heating was determined in vivo below eight EEG electrodes, using both head and body coil transmission and sequences covering the whole range of SAR values.

Results:

Head transmit coil: temperature increases were below 2.2°C for low SAR sequences, but reached 4.6°C (one subject, clavicle) for high SAR sequences; the equilibrium temperature Teq remained below 39°C. Body transmit coil: temperature increases were higher and more frequent over subjects and electrodes, with values below 2.6°C for low SAR sequences, reaching 6.9°C for high SAR sequences (T8 electrode) with Teq exceeding a critical level of 40°C.

Conclusion:

Anatomical imaging should be based on T1‐weighted sequences (FLASH, MPRAGE, MDEFT) with an SAR below values for functional MRI sequences based on gradient echo planar imaging. Anatomical sequences with a high SAR can pose a significant risk, which is reduced by using head coil transmission. J. Magn. Reson. Imaging 2012;35:561‐571. © 2011 Wiley Periodicals, Inc.
Effect of technological processing and preservation method on amino acid content and protein quality in kale (Brassica oleracea L. var. acephala) leaves
Authors: Korus Anna
Published: October 2011

BACKGROUND: The aim of the investigation was to evaluate the level of amino acids and quality of protein in raw and processed kale leaves.

RESULTS: In all samples the dominant amino acids in g kg−1 raw matter were glutamic acid, aspartic acid and proline. In raw kale leaves the limiting amino acids were lysine, isoleucine and cystine with methionine, and in the remaining products also valine and leucine. Blanched kale leaves contained 88% of the amino acid content in raw leaves, 76% in cooked leaves, and 69–77% and 71–72% of initial levels in frozen and canned products, respectively. In raw, blanched and cooked leaves essential amino acids comprised 44%, 44% and 47%, respectively, of total amino acids; in frozen and canned leaves the proportions were 46% and 44%, respectively. The essential amino acid index was 97 for canned products, 100–109 for frozen leaves, and 117 for raw kale leaves.

CONCLUSION: Raw and processed (blanched or cooked) kale leaves are a good source of amino acids. Copyright © 2011 Society of Chemical Industry
A survey of free and conjugated deoxynivalenol in the 2008 corn crop in Ontario, Canada
Authors: Tran Si‐Trung , Smith Trevor K , Girgis George N
Published: October 2011

BACKGROUND: Deoxynivalenol (DON, vomitoxin), one of the most important mycotoxins produced by many Fusarium species, is found as a common contaminant of crops worldwide. Recent studies have described the presence of conjugated forms of DON (glycosides and fatty acid). The aim of the current study was therefore to investigate the natural occurrence of free and conjugated DON in Canadian corn.

RESULTS: Free and conjugated DON was determined by gas chromatography‐mass spectrometry (GC‐MS) and enzyme‐linked immunosorbent assay (ELISA) in 86 corn samples collected from the 2008 crop in Ontario, Canada. Free DON concentrations determined by ELISA were similar to values determined in most samples using GC‐MS. Conjugated DON was detected in 72 samples. Levels of free DON ranged from 0.17 to 14.00 µg g−1 using GC‐MS. The highest levels of free DON were found in corn samples from the southern and southwestern regions of Ontario, while samples from eastern regions were less contaminated. Conjugated DON was found mainly in corn from the east‐central region, with five of six samples showing high levels of conjugated DON (up to 43% increase in DON following acid hydrolysis). Low levels of conjugated DON (≤10% increase in DON following acid hydrolysis) were detected in the majority of corn samples from the southwestern region (nine of 19 samples) and from the central region (16 of 36 samples).

CONCLUSION: The current survey emphasizes the frequency of conjugated DON in Ontario grown corn and the potential challenges in understanding the hazard posed by DON‐contaminated foodstuffs and feedstuffs. Copyright © 2011 Society of Chemical Industry
Molecularly imprinted polymer for selective extraction of 3‐methylflavone‐8‐carboxylic acid from human urine followed by its determination using zwitterionic hydrophilic interaction liquid chromatography
Authors: Rao Ramisetti N. , Maurya Pawan K. , Kuntamukkala Ramakrishna , Vitthal Wani D. , Talluri Murali V. N. K.
Published: October 2011

A novel water‐compatible molecularly imprinted SPE combined with zwitterionic hydrophilic interaction liquid chromatography method for selective extraction and determination of 3‐methylflavone‐8‐carboxylic acid (MFA), the main active metabolite of flavoxate in human urine, was developed and validated. The effects of progenic solvents, pH, cross linker and amount of monomer were studied to optimize the efficiency and selectivity. The molecularly imprinted polymer showed good specific adsorption capacity with an optimum of 200 μmol/g at pH 7.5 and selective extraction of MFA from human urine. The recovery of MFA from human urine was >98%. The lower limit of quantification was 1.20 μg/mL. The proposed method overcomes the matrix effects of endogenous substances generally encountered during direct analysis of urine sample.
Expansion and Efficiency in Banking: Evidence from Ghana
Authors: Isshaq Zangina , Bokpin Godfred A.
Published: October 2011

We use a translog functional form to estimate a stochastic frontier function of cost and profit efficiency (PE) of Ghanaian banks under the Battese–Coelli time‐varying decaying inefficiency parameterization for (unbalanced) panel data. We regressed efficiency estimates on a distance variable controlling for bank size, total cost, and profits. We find that Ghanaian bank PE is worsening, whereas cost efficiency is improving for the period analyzed. Our results show that PE is not related to distance, size, or cost and profitability ratios. Distance is however positively and significantly related to cost efficiency. Cost efficiency is however not influenced by size or cost and profit ratios. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and bioactivity evaluation of novel spiromesifen derivatives
Authors: Zhao Jin‐Hao , Wang Zong‐Cheng , Ji Ming‐Hua , Cheng Jing‐Li , Zhu Guo‐Nian , Yu Chuan‐Ming
Published: October 2011

BACKGROUND: The development of environmentally friendly and novel structural pesticides is now an area of intense research in the agriculture field. Spirocyclic tetronic acids such as spiromesifen are typical compounds of this kind. In order to discover novel compounds with improved and broader‐spectrum insecticidal activities, a series of spiromesifen derivatives were synthesised and bioassayed.

RESULTS: The derivatives were identified by 1H NMR and MS. Preliminary bioassays demonstrated that some bioactivities of compounds 5a to 5u were better and had a broader spectrum than the lead compound spiromesifen. Moreover, these compounds showed better insecticidal activities against Mythimna sepatara and Aphis fabae than acaricidal activities against Tetranychus cinnabari. Furthermore, LC50 of 5s against Aphis fabae reached 1.09 mg L−1. At the same time, compounds 5g, 5i, 5k and 5r also warrant further study because of their superior bioactivities to spiromesifen. What is more, suitable carbon chain length in the 4‐position ester and the log P value of these spiromesifen derivatives dramatically influenced their insecticidal activities. Butyric or pentanoic ester and a log P value of 4.0–6.0 may be preferred.

CONCLUSION: The present work demonstrates that some spiromesifen derivatives can be used as potential lead compounds for developing novel insecticides and acaricides. Copyright © 2011 Society of Chemical Industry
Improved biological effects of uniconazole using porous hollow silica nanoparticles as carriers
Authors: Tan Wei‐Ming , Hou Ning , Pang Sen , Zhu Xiao‐Feng , Li Zhao‐Hu , Wen Li‐Xiong , Duan Liu‐Sheng
Published: October 2011

BACKGROUND: The aim of this work is to prepare a controlled‐release formulation of uniconazole using porous hollow silica nanoparticles (PHSNs) as carrier, and to investigate the biological effects on rice growth.

RESULTS: PHSNs with a shell thickness of ∼15 nm and a particle size of 80–100 nm were synthesised through a sol–gel route using nanosized calcium carbonate particles as templates. Simple immersing (SI) and supercritical fluid drug loading (SFDL) technologies were employed to load uniconazole into PHSNs with loading efficiencies of ∼22 and ∼26% respectively. The prepared uniconazole‐loaded PHSNs (UCZ‐PHSNs) by SI and SFDL both demonstrated sustained release properties, and the latter showed better controlled release ability with a slower release rate. Compared with free uniconazole, UCZ‐PHSNs exhibited a weaker growth retardation effect in the early stage but more significant retardation ability in later stages for agar‐cultured rice seedlings. For the rice that grew in clay, UCZ‐PHSNs demonstrated a weaker plant height retardation effect than free uniconazole at the early jointing stage by foliar spraying, but exhibited a stronger retardation capacity than free uniconazole by being applied into soil before seedling transplantation.

CONCLUSION: The results indicated that the prepared UCZ‐PHSNs possessed good controlled‐release properties and had improved retardation effects on rice growth. It is recommended that UCZ‐PHSNs be applied into soil before seedling transplantation rather than administered by foliar spraying at the early jointing stage. Copyright © 2011 Society of Chemical Industry
De novo design, synthesis and solution conformational study of two didehydroundecapeptides: effect of nature and number of amino acids interspersed between Phe residues
Authors: Dutta Madhvi Gupta , Mathur Puniti , Chauhan Virander S
Published: October 2011

De novo design of peptides and proteins has recently surfaced as an approach for investigating protein structure and function. This approach vitally tests our knowledge of protein folding and function, while also laying the groundwork for the fabrication of proteins with properties not precedented in nature. The success relies heavily on the ability to design relatively short peptides that can espouse stable secondary structures. To this end, substitution with α,β‐didehydroamino acids, especially α,β‐didehydrophenylalanine (ΔzPhe), comes in use for spawning well‐defined structural motifs. Introduction of ΔPhe induces β‐bends in small and 310‐helices in longer peptide sequences. The present work aims to investigate the effect of nature and the number of amino acids interspersed between two ΔPhe residues in two model undecapeptides, Ac‐Gly‐Ala‐ΔPhe‐Ile‐Val‐ΔPhe‐Ile‐Val‐ΔPhe‐Ala‐Gly‐NH2 (I) and Boc‐Val‐ΔPhe‐Phe‐Ala‐Phe‐ΔPhe‐Phe‐Leu‐Ala‐ΔPhe‐Gly‐OMe (II). Peptide I was synthesized using solid‐phase chemistry and characterized using circular dichroism spectroscopy. Peptide II was synthesized using solution‐phase chemistry and characterized using circular dichroism and nuclear magnetic resonance spectroscopy. Peptide I was designed to examine the effect of incorporating β‐strand‐favoring residues like valine and isoleucine as spacers between two ΔPhe residues on the final conformation of the resulting peptide. Circular dichroism studies on this peptide have shown the existence of a 310‐helical conformation. Peptide II possesses three amino acids as spacers between ΔPhe residues and has been reported to adopt a mixed 310/α‐helical conformation using circular dichroism and nuclear magnetic resonance spectroscopy studies. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Phase determination of crystal structure factor using measured rocking curves
Authors: Negishi Riichirou , Fukamachi Tomoe , Yoshizawa Masami , Hirano Kenji , Hirano Keiichi , Kawamura Takaaki
Published: October 2011

We report on a novel phase determination method of crystal structure factor using phase difference Δφ between the interference fringes of the diffracted intensities and those of the transmitted intensities. It is an advantage that the phase of crystal structure factor can be determined using the anomalous scattering only at one wavelength. We demonstrate the method by applying to GaAs 200 reflection near K‐absorption edges of Ga and As.
Real‐time analysis of the microstructural evolution and optical properties of Cu(In,Ga)Se2 thin films as a function of Cu content
Authors: Ranjan Vikash , Collins R. W. , Marsillac Sylvain
Published: October 2011

Thin films of Cu(In,Ga)Se2 with various copper contents were deposited by co‐evaporation onto thermally oxidized silicon substrates. Characterization by real‐time spectroscopic ellipsometry reveals clear similarities among the samples, as well as key variations with Cu content. Although all films exhibit a Volmer–Weber nucleation and similar fundamental critical point energies in the analysis of optical properties, Cu‐rich films exhibit enhanced coalescence, smoother surfaces, larger grain sizes, as well as a sub‐bandgap absorption which is absent in Cu‐poor films. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Constraints on the impact of radar rainfall data assimilation on forecasts of cumulus convection
Authors: Craig George C. , Keil Christian , Leuenberger Daniel
Published: October 2011

Experience from operational trials of assimilation of radar data in kilometre‐scale numerical weather prediction models (operating without cumulus parametrization) shows that the positive impact of the radar data on convective precipitation forecasts typically decays within a few hours, although certain cases show much longer impact time‐scales. In this work the impact time of radar data assimilation is related to characteristics of the meteorological environment. Three cases of convection over southern Germany with different synoptic conditions are investigated (one case with two data assimilation cut‐off times), each with an ensemble of ten forecasts at 2.8 km horizontal resolution based on different initial and boundary conditions from a global forecast ensemble. Control forecasts are compared with forecasts where radar rainfall data are assimilated using latent heat nudging. The impact time of the radar data on total precipitation is quantified, and found to correlate well with a convective time‐scale that measures the rate at which convection is responding to changes in large‐scale forcing. Short impact times were associated with short convective time‐scales that are characteristic of equilibrium convection. In this regime the statistical properties of the convection are constrained by the large‐scale forcing, and effects of the radar data are lost within a few hours as the convection rapidly returns to equilibrium. When the convective time‐scale was large (non‐equilibrium conditions), the impact of the radar data was longer since convective systems were triggered by the latent heat nudging and were able to persist for many hours in the very unstable conditions present in these cases. The impact of the assimilated radar data on the location of precipitation was assessed using the equitable threat score (ETS) and the displacement and amplitude score (DAS). The impact times for these measures were consistently shorter than for total precipitation, but again shortest for the equilibrium conditions. Copyright © 2011 Royal Meteorological Society
Sensitivity and out‐of‐sample error in continuous time data assimilation
Authors: Bröcker Jochen , Szendro Ivan G.
Published: October 2011

Data assimilation refers to the problem of finding trajectories of a prescribed dynamical model in such a way that the output of the model (usually some function of the model states) follows a given time series of observations. Typically though, these two requirements cannot both be met at the same time–tracking the observations is not possible without the trajectory deviating from the proposed model equations, while adherence to the model requires deviations from the observations. Thus, data assimilation faces a trade‐off. In this contribution, the sensitivity of the data assimilation with respect to perturbations in the observations is identified as the parameter which controls the trade‐off. A relation between the sensitivity and the out‐of‐sample error is established, which allows the latter to be calculated under operational conditions. A minimum out‐of‐sample error is proposed as a criterion to set an appropriate sensitivity and to settle the discussed trade‐off. Two approaches to data assimilation are considered, namely variational data assimilation and Newtonian nudging, also known as synchronization. Numerical examples demonstrate the feasibility of the approach. Copyright © 2011 Royal Meteorological Society
Multiresponse Optimization and Pareto Frontiers
Authors: Costa Nuno Ricardo , Lourenço João , Pereira Zulema Lopes
Published: October 2011

Methods that can capture evenly distributed solutions along the Pareto frontier are useful for multiresponse optimization problems because they provide a large variety of alternative solutions to the decision maker from among a set of nondominated solutions. However, methods often used for optimizing dual and multiple dual response problems have been rarely evaluated in terms of their ability to capture those solutions. This article provides this information by evaluating a global criterion–based method and the popular weighted mean square error method. Convex and nonconvex response surfaces were considered, and results of the methods were compared with those of a lexicographic approach on the basis of two examples from the literature. Regarding the results, it is shown that the user can be successful in capturing Pareto solutions in convex and nonconvex regions using the global criterion–based method. Moreover, it is shown that the starting point affects the distribution of solutions along the Pareto frontier but is not pivotal to obtain a complete representation of the Pareto frontier. For this purpose, it is necessary to decrease the weight increment and to compute for more solutions. Copyright © 2011 John Wiley & Sons, Ltd.
Wave packet dynamics on multiply‐valued potential surfaces: Report on work in progress
Authors: Hall Benjamin , Deumens Erik , Öhrn Yngve , Sabin John R.
Published: October 2011

A perennial problem in quantum scattering calculations is reducing the 3N degrees of freedom (three for each atom or electron present) to a more computationally manageable number, while still retaining the information present in each degree of freedom. We present a method of extracting a nonadiabatic, multiply‐valued potential‐energy surface from electron nuclear dynamics (Deumens et al., Rev Mod Phys, 1994, 66, 917) trajectories; we then perform nuclear wave packet dynamics on that surface and calculate differential cross sections for two‐center, one‐active‐electron systems. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Quasi sliding mode‐based single input fuzzy self‐tuning decoupled fuzzy PI control for robot manipulators with uncertainty
Authors: Amer Ahmed F. , Sallam Elsayed A. , Elawady Wael M.
Published: October 2011

This paper presents a robust adaptive control strategy for robot manipulators, based on the coupling of the fuzzy logic control with the so‐called sliding mode control (SMC) approach. The motivation for using SMC in robotics mainly relies on its appreciable features. However, the drawbacks of the conventional SMC, such as chattering effect and required a priori knowledge of the bounds of uncertainties can be destructive. In this paper, these problems are suitably circumvented by adopting a reduced rule base single input fuzzy self tuning decoupled fuzzy proportional integral sliding mode control approach. In this new approach a decoupled fuzzy proportional integral control is used and a reduced rule base single input fuzzy self‐tuning controller as a supervisory fuzzy system is added to adaptively tune the output control gain of the decoupled fuzzy proportional integral control. Moreover, it is proved that the fuzzy control surface of the single‐input fuzzy rule base is very close to the input/output relation of a straight line. Therefore, a varying output gain decoupled fuzzy proportional integral sliding mode control approach using an approximate line equation is then proposed. The stability of the system is guaranteed in the sense of the Lyapunov theorem. Simulations using the dynamic model of a 3DOF planar manipulator with uncertainties show the effectiveness of the approach in high speed trajectory tracking problems. The simulation results that are compared with the results of conventional SMC indicate that the control performance of the robot system is satisfactory and the proposed approach can achieve favorable tracking performance, and it is robust with regard to uncertainties and disturbances. Copyright © 2011 John Wiley & Sons, Ltd.
Distributed output regulation of leader–follower multi‐agent systems
Authors: Hong Yiguang , Wang Xiaoli , Jiang Zhong‐Ping
Published: October 2011

In this paper, distributed leader–follower control algorithms are presented for linear multi‐agent systems based on output regulation theory and internal model principle. By treating a leader to be followed as an exosystem, the proposed framework can be used to generalize existing multi‐agent coordination solutions to allow the identical agents to track an active leader with different dynamics and unmeasurable variables. Moreover, the obtained results for multi‐agent coordination control are an extension of previous work on centralized and decentralized output regulation to a distributed control context. Necessary and sufficient conditions for the distributed output regulation problem are given. Finally, distributed output regulation of some classes of multi‐agent systems with switching interconnection topologies are discussed via both static and dynamic feedback. Copyright © 2011 John Wiley & Sons, Ltd.
Simple estimation of hidden correlation in repeated measures
Authors: Nguyen Thuan , Jiang Jiming
Published: October 2011

In medical and social studies, it is often desirable to assess the correlation between characteristics of interest that are not directly observable. In such cases, repeated measures are often available, but the correlation between the repeated measures is not the same as that between the true characteristics that are confounded with the measurement errors. The latter is called the hidden correlation. Previously, the problem has been treated by assuming prior knowledge about the measurement errors or by using relatively complex statistical models, such as the mixed‐effects models, with no closed‐form expression for the estimated hidden correlation. We propose a simple estimator of the hidden correlation that is very much like the Pearson correlation coefficient, with a closed‐form expression, under assumptions much weaker than the mixed‐effects model. Simulation results show that the proposed simple estimator performs similarly as the restricted maximum likelihood (REML) estimator in mixed models but is computationally much more efficient than REML. We also made simulation comparison with the Pearson correlation. We considered a real data example. Copyright © 2011 John Wiley & Sons, Ltd.
Guest Effect on Nanopatterned Spin‐Crossover Thin Films
Authors: Bartual‐Murgui Carlos , Akou Amal , Salmon Lionel , Molnár Gábor , Thibault Christophe , Real Jose Antonio , Bousseksou Azzedine
Published: October 2011

Nanopatterned thin films of the metal–organic framework {Fe(bpac)[Pt(CN)4]} (bpac=bis(4‐pyridyl)acetylene) are elaborated by the combination of a sequential assembly process and a lithographic method. Raman microspectroscopy is used to probe the temperature dependence of the spin state of the iron(II) ions in the films (40–90 nm in thickness), and reveals an incomplete but cooperative spin transition comparable to that of the bulk material. Adsorption/desorption of pyridine guest molecules is found to have a substantial influence on the spin‐crossover properties of the thin layers. This interplay between host–guest and spin‐crossover properties in thin films and nanopatterns demonstrates the potential ability of using this kind of material as a microsensor.
Prediction of long‐term outcome in glycine encephalopathy: a clinical survey
Authors: Hennermann Julia B. , Berger Jeanne‐Marie , Grieben Ulrike , Scharer Gunter , Van Hove Johan L. K.
Published: October 2011

Objective

Glycine encephalopathy (GE) is a rare autosomal recessive inborn error of glycine degradation resulting in severe encephalopathy with ensuing poor outcome. Attenuated variants with a significantly better outcome have been reported. Early prediction of long‐term outcome is not yet possible.

Methods

We compared the clinical and biochemical features of 45 children, each with a different course of the disease, to help determine predictors of long‐term outcome.

Results

The most common presenting symptoms were hypotonia, seizures, and coma. In this study, 85% of the patients presented within the first week of life, and 15% presented after the neonatal period up to the age of 12 months. Developmental progress was made by 19% of those children presenting during the neonatal period and by 50% of those presenting in infancy. Initial CSF and plasma glycine concentrations were not useful in differentiating severe and attenuated outcome. A severe outcome was significantly associated with early onset of spasticity, frequent hiccupping, EEG burst‐suppression or hypsarrhythmia patterns, microcephaly, and congenital or cerebral malformations, e.g. corpus callosum hypoplasia. An attenuated outcome was significantly associated with hyperactivity and choreiform movement disorders. We describe a severity score which facilitates the prediction of the outcome in patients with GE.

Conclusion

Prediction of the outcome of GE may be facilitated by recognizing selected clinical parameters and early neuroimaging findings.
Norms and high-level cognition: Consequences, trends, and antidotes
Authors: McNair Simon , Feeney Aidan
Published: October 2011

We are neither as pessimistic nor as optimistic as Elqayam & Evans (E&E). The consequences of normativism have not been uniformly disastrous, even among the examples they consider. However, normativism won't be going away any time soon and in the literature on causal Bayes nets new debates about normativism are emerging. Finally, we suggest that to concentrate on expert reasoners as an antidote to normativism may limit the contribution of research on thinking to basic psychological science.
On weak mixing, minimality and weak disjointness of all iterates
Authors: KWIETNIAK DOMINIK , OPROCHA PIOTR
Published: October 2011

This article addresses some open questions about the relations between the topological weak mixing property and the transitivity of the map f×f2×⋯×fm, where f:X→X is a topological dynamical system on a compact metric space. The theorem stating that a weakly mixing and strongly transitive system is Δ-transitive is extended to a non-invertible case with a simple proof. Two examples are constructed, answering the questions posed by Moothathu [Diagonal points having dense orbit. Colloq. Math. 120(1) (2010), 127–138]. The first one is a multi-transitive non-weakly mixing system, and the second one is a weakly mixing non-multi-transitive system. The examples are special spacing shifts. The latter shows that the assumption of minimality in the multiple recurrence theorem cannot be replaced by weak mixing.
Multiplexing Performance Assessment of POCET Method for Compass B1/B3 Signals
Authors: Zhang Kai , Zhou Hongwei , Wang Feixue
Published: October 2011

Compared with traditional GPS signals, modern GNSS signals are much more complex and have various new modulations. This introduces a difficulty in combining multiple signal components into a constant-envelope signal that maximises the power efficiency of High Power Amplifiers (HPA) on satellites. This paper first describes the fundamental Phase-Optimised Constant-Envelope Transmission (POCET) technique that searches the optimum combining solution for multiple binary navigation signals. Then the Compass B1/B3 signals are modelled by POCET. For the B1 band, a binary complex sub-carrier is adopted to implement the centre frequency difference between regional and global Compass navigation systems. Regional B1 Open Service (OS) signals and global TMBOC signals are combined with optimum loss of 1·0 dB. For the B3 band, Interplex modulation is proved to be the optimum method to combine QPSK (10) and BOC (15, 2·5) signals. Signal quality in the presence of finite word-length effects of Digital-Analog (DA) converters is analysed. Simulations for signal model validation are conducted. The result indicates that relative amplitude error less than 0·01 and angle error less than 0·1 degree can be achieved with 10 bit DA converters. The POCET method is demonstrated as an efficient solution for Compass signals.
Assessment of Radio Frequency Compatibility between Compass Phase II and Other GNSSs
Authors: Liu Li , Zhan Xingqun , Liu Wei , Niu Mancang
Published: October 2011

As the technology of global navigation satellite system (GNSS) and augmentation systems are evolving rapidly, compatibility becomes a critical issue for system providers. By April 2011, China had successfully launched eight satellites of the Compass phase II (CP II) navigation system, which will provide positioning, navigation, timing and communication services to the Asia-Pacific region by the year 2012. Due to the limitations of available radio frequency bandwidths, it is important to assess the compatibility and to design signals based on the compatibility within these limited radio frequency bandwidths. This paper presents a modified compatibility assessment methodology, derived from the traditional methodologies that are based on the spectral separation coefficient (SSC) and the effective carrier-power-to-noise density ratio. The modified methodology takes into account additional factors including the Doppler offset, code tracking loop, and band-limiting, sampling and quantisation (BSQ) of the GNSS receiver. In the simulation section, the comprehensive compatibility assessment between CP II and other GNSSs, such as GPS, Galileo, Wide Area Augmentation System (WAAS) and European Geostationary Navigation Overlay Service (EGNOS) on L1 Band are carried out and presented with some new results. Simulation results reveal that CP II does not cause serious interference on GPS, Galileo, WAAS and EGNOS as the interference level is below the 0·25 dB threshold recommended by ITU.
A Study for IGSO Inclination Angles in the Transmitting Satellite Navigation Constellation
Authors: Ma Lihua , Ai Guoxiang , Ji Haifu
Published: October 2011

Unlike a direct broadcasting satellite navigation system, the transmitting satellite navigation system developed in China uses transponders onboard communication satellites to retransmit navigation signals generated at a ground master station. The transmitting navigation satellite constellation consists of a number of inclined geosynchronous orbit (IGSO) satellites. Considering China's mainland coverage in the northern hemisphere occupies some 62 degrees in longitude, the inclination of the IGSO satellites cannot be too high, or its signals would not be received by the users in the middle and high latitude areas when the IGSO satellite travels over the southern hemisphere. Meanwhile, the latitude of the most southerly station in China mainland that can uplink navigation signals is about 18°N when the IGSO satellite travels to the southern hemisphere. Therefore, there is a need to consider the IGSO inclination to achieve balance between uplinking high-quality navigation signals and covering the high-latitude area. In this work, the navigation performance and availability of the IGSO satellite are examined when navigation signals are uplinked from the stations Lintong and Sanya.
Minimum-Wage Policy and Constitutional Inequality: The Paradox of the Fair Labor Standards Act of 1938
Authors: Hart Vivien
Published: October 2011

The minimum wage was conceived as an attack on poverty within the work force. Americans first defined “sweated labor” as a category and a social problem, then wrote solutions into law which fundamentally changed that definition and undermined the original purpose. First, in 1912, a problem of economic exploitation of workers became a problem of women unable to protect themselves. Transformed into an issue of the rights of labor, in the Fair Labor Standards Act of 1938 (FLSA) a radically new minimum wage law left those most in need unprotected.
Discovering Patterns in Regulatory History: Continuity, Change, and Regulatory Regimes
Authors: Eisner Marc Allen
Published: October 2011

From contesting the power of large corporations to nurturing a stable industrial economy, regulatory policies have been created in pursuit of a wide variety of goals. Likewise, regulatory institutions have been designed to address host of administrative demands, to incorporate organized interests into the policy process, and to compensate for specific problems of implementation. One can analyze each expansion of regulatory authority as an independentevent. However, one can bring order to the history of regulation by identifying particularregimesthat have emerged during critical periods in U.S. history. When used in international relations, a regime is commonly defined as “a set of principles, norms, rules, and procedures around which actors' expectations converge.” In this context, regimes are important because they “constrain and regularize the behavior of participants, affect which issues among protagonists move on and off agendas, determine which activities are legitimized or condemned, and influence whether, when, and how conflicts are resolved.” While retaining the emphasis on a value-based governance structure, we can define a regulatory regime asa linked set of policies and institutions that condition the relationship between societal interests, the state, economic actors in multiple sectors of the economy. A regime framework focuses attention on points of continuity in policy and institutional change. It facilitates the discovery of patterns in regulatory policies and institutions and provides a useful explanatory and organizational tool.
The Myth of Class in Jacksonian America
Authors: Gienapp William E.
Published: October 2011

In the mid-1960s, Charles G. Sellers, Jr., was perhaps the most widely respected historian of the Jacksonian era. The author of several seminal articles on the period, he was in the midst of writing a multivolume biography of James K. Polk, two volumes of which had already appeared. Sellers's knowledge of the intricacies of Jacksonian politics, his comprehension of the importance of state politics, and his understanding of the relationship between society and politics were unrivaled. The second volume of his study of Polk received the Bancroft Prize, and Jacksonian scholars eagerly awaited the appearance of the promised third volume, covering the most crucial years of Polk's presidency.
World Population Growth, Family Planning, and American Foreign Policy
Authors: Sharpless John
Published: October 2011

The U.S. government position on world population growth as it emerged in the early 1960s was a fundamental departure in both content and commitment. We embraced the idea that one of the goals of American foreign policy should be the simultaneous reduction ofbothmortality and fertility across the Third World. It was not simply rhetoric. As the years passed, we committed a growing portion of our foreign aid to that end. The decision to link U.S. foreign-policy objectives with the subsidy of family planning and population control was truly exceptional in that it explicitly aimed at altering the demographic structure of foreign countries through long-term intervention. No nation had ever set in motion a foreign-policy initiative of such magnitude. Its ultimate goal was no less than to alter the basic fertility behavior of the entire Third World! Whether one views this goal as idealistic and naive or as arrogant and self-serving, the project was truly of herculean proportions.