bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel lightweight authentication scheme with anonymity for roaming service in global mobility networks
Authors: Wu Shuhua , Zhu Yuefei , Pu Qiong
Published: September 2010

Recently, two authentication schemes with anonymity for roaming service in wireless networks were proposed by Heet al. and Xuet al.In this paper we point out that neither of the two schemes is sufficiently practical owing to the high computational cost involved. Furthermore, we also find that both schemes still have some weaknesses which allow the attacker to trace a certain user's behaviors and thus infer his real identity. Thereafter, we propose a novel lightweight authentication scheme with anonymity for roaming service in global mobility networks to overcome the aforementioned defects. Moreover, we formally analyze our proposed scheme with BAN‐logic and show that it can withstand several possible attacks. Copyright © 2010 John Wiley & Sons, Ltd.
Long term G‐CSF‐induced remission of ulcerative colitis‐like inflammatory bowel disease in a patient with glycogen storage disease Ib and evaluation of associated neutrophil function
Authors: Alsultan Abdulrahman , Sokol Ronald J. , Lovell Mark A. , Thurman Gail , Ambruso Daniel R.
Published: September 2010

We present a 23‐year‐old female with Glycogen storage disease Ib (GSD Ib) who was diagnosed with ulcerative colitis‐like inflammatory bowel disease (IBD) at 7 years of age. G‐CSF therapy reversed the IBD, was required to maintain IBD remission and was well tolerated. Neutrophil functions at time of diagnosis showed impaired chemotaxis but normal superoxide anion production and bactericidal activity. Ulcerative colitis‐like IBD may also be seen in GSD Ib and is responsive to G‐CSF therapy. Neutrophil dysfunction is variable among patients with GSD Ib. Pediatr Blood Cancer. 2010;55:1410–1413. © 2010 Wiley‐Liss, Inc.
Serum prohepcidin concentrations at birth and 1 month after birth in premature infants
Authors: Kitajima Junko , Ohga Shouichi , Kinjo Tadamune , Ochiai Masayuki , Takahata Yasushi , Honjo Satoshi , Hara Toshiro
Published: September 2010

Background

Premature newborns are vulnerable to iron imbalance, although the iron homeostasis during the perinatal period remains unclear. To clarify the iron metabolism of premature infants, we measured serum prohepcidin concentrations of preterm infants, and analyzed the association with iron parameters.

Methods

Seventy‐one (61 preterm and 10 term) infants were enrolled for the study, that had no underlying diseases including asphyxia, bleedings, infection, and anomalies. Serum concentrations of prohepcidin at birth and 1 month after birth were determined by enzyme‐linked immunosorbent assay.

Results

Prohepcidin levels at birth but not 1 month postnatal age positively correlated with gestational age (correlation coefficient [CC]:0.334, P = 0.005) and birth weight (CC: 0.367, P = 0.002). The levels at birth of preterm infants (median: 29.93 ng/ml, range: 4.0–110.6) were lower than those of full‐term infants, and increased thereafter. On the other hand, the levels in small‐for‐gestational age infants were not associated with gestational age or birth weight. Prohepcidin levels at birth correlated positively with red cell counts (CC = 0.487, P = 0.025), unsaturated iron binding capacity (CC = 0.755, P = 0.001), total protein (CC = 0.624, P = 0.005), and serum albumin levels (CC = 0.500, P = 0.025), and negatively with serum iron levels (CC = −0.688, P = 0.003), but not ferritin levels. Multivariate analyses indicated that prohepcidin levels at birth were lower in infants with pregnancy‐induced hypertension (P = 0.03) or premature rupture of membrane (P = 0.01).

Conclusions

Prohepcidin production was physiologically low at birth of preterm infants according to the gestational age, and the levels might be susceptible to the in utero stress. The postnatal increase might reflect the maturation and/or adaptation of iron homeostasis. Pediatr Blood Cancer 2011;56:267–272. © 2010 Wiley‐Liss, Inc.
Improved sorting of carbon nanotubes according to electronic type by density gradient ultracentrifugation
Authors: Posseckardt Juliane , Battie Yann , Fleurier Romain , Lauret Jean‐Sébastien , Loiseau Annick , Jost Oliver , Mertig Michael
Published: September 2010

A variety of fabrication methods for single‐walled carbon nanotubes (SWCNTs) has been developed, but none of them has been proven to generate tubes of only one chirality. Hence, a sample of as‐produced SWCNTs always consists of a mixture of metallic and semiconducting tubes. By this, the application of SWCNTs in electronics, optics and sensing is limited today. Recently, the sorting of carbon nanotubes using density gradient ultracentrifugation (DGU) has been demonstrated. We report on an improved sorting according to electronic type by applying a two‐step procedure: In the first step, we enriched semiconducting SWCNTs via DGU. In the second step, the sorted fractions have been reinserted and a second DGU was performed, winnowing metallic SWCNTs. Employing this procedure, we were able to reduce the content of metallic SWCNTs from 38 to 11%. Furthermore, we assembled carbon nanotube field‐effect transistors with a high ON/OFF ratio from the sorted fraction in a single step by dielectrophoresis.
Host–guest interaction between single‐wall carbon nanotubes and encapsulated C60 probed by resonance Raman spectroscopy
Authors: Joung Soon‐Kil , Okazaki Toshiya , Okada Susumu , Iijima Sumio
Published: September 2010

Single‐wall carbon nanotubes (SWCNTs) that are encapsulating C60 [nanopeapods (NPDs)] can be considered one of the best model systems for investigating host–guest interactions in π‐conjugated molecular systems. We thus have investigated the effects of C60 encapsulation on the radial breathing mode (RBM) frequencies of semiconducting SWCNTs in a wide range of diameters (dt = ∼1.23 − 1.5 nm). The observed frequency shifts show a characteristic behavior depending on the intermolecular spacing between encapsulated C60 and the host SWCNTs. The present findings clearly indicate the van der Waals nature of the SWCNT‐C60 interaction.
Electron spin resonance on single‐walled carbon nanotubes obtained from different sources
Authors: Ferrer‐Anglada Núria , Monge Aida Abiad , Roth Siegmar
Published: September 2010

We used electron spin resonance (ESR) to analyze several kinds of single‐walled carbon nanotubes (SWNTs) synthesized by different methods. We observed that ESR is a sensitive probe that can be used to observe major differences between samples of carbon nanotubes (CNTs), in relation to their proportion of magnetic catalysts, impurities or defects. We analyzed the ESR spectra of CNTs in the usual way, by three overlapping lines. We then, implemented a function to fit the spectra, which gave us the intensity, line width (ΔHPP), and resonance line position (g factor) of each component line. The asymmetric line, which is assigned to the conduction electrons, could be used as a fingerprint of CNT purity. However, this asymmetric line is not always observed, since the three ESR lines often overlap, particularly when there is a large amount of paramagnetic ions. We studied the ESR spectra for different samples and estimated their purity by comparing the resulting parameters with data obtained by Raman spectroscopy on the same samples.
Electronic structure, effective masses, mechanical and thermo‐acoustic properties of cubic HfO2 under pressure
Authors: Liu Qi‐Jun , Liu Zheng‐Tang , Feng Li‐Ping , Xu Bing
Published: September 2010

Electronic structure, effective masses, mechanical and thermo‐acoustic properties of cubic HfO2 at applied hydrostatic pressure up to 50 GPa have been investigated using the plane‐wave ultrasoft pseudopotential technique based on the first‐principles density‐functional theory (DFT). The calculated ground‐state properties are in good agreement with previous data, and the band gaps increase versus pressure. The valence‐ and conduction‐band effective masses for the first time have been theoretically predicted under different pressures, and the calculated carrier effective masses are shown to be anisotropic. The three independent elastic constants C11, C12 and C44 for cubic HfO2 have been calculated at zero pressure and high pressure. Using the Voigt, Reuss and Hill theory, the bulk, shear and Young's moduli and Poisson coefficients have been obtained at the applied pressure. From the obtained elastic constants, the acoustic velocity and Debye temperature ${\Theta }_{{\rm D}} $ have been estimated versus pressure. The results obtained at 0 GPa are consistent with the previous data.
Gradient nanowires and nanotubes
Authors: Agarwal S. , Eckhardt B. , Grossmann F. , Greiner A. , Göring P. , Wehrspohn R. B. , Wendorff J.
Published: September 2010

Different routes to prepare gradient nanowire and nanotubes are presented including the use of polymeric and metal nanoparticles. In the case of electrospinning, latex particles have been added to electrospinning solution. The properties of the fibres have been studied theoretically and experimentally. In the case of face‐to‐face‐wetting of porous templates, solution as well as melt wetting for different polymeric composition from both sides of the template is carried out. It turned out that solution wetting leads to an intermixing of the compounds whereas as melt wetting leads to sharp compositional interfaces. The method has been extended to include plasmonic and magnetic nanoparticles for nanophotonic applications.

magnified image
Characterization of nanowires with the low energy electron point source (LEEPS) microscope
Authors: Beyer André , Weber Dirk H. , Völkel Berthold , Gölzhäuser Armin
Published: September 2010

The low energy electron point source (LEEPS) microscope is an instrument for the characterization of structural, electrical, and mechanical properties of single molecules and nanostructures. In this work, we review our efforts in advancing LEEPS as tool for the characterization of electric properties of nanowires. Individual nanowires of different size and material were examined, including compositions of metallic as well as semiconducting character. The nanowires were characterized by electrical conductance measurements with a metallic tip as movable electrode and the sample support as its counterpart. Beyond these measurements, we developed a scheme to deduce the electrical conductivity of a single nanowire directly from its LEEPS image. This substantially reduces the data acquisition time and widens the applicability of LEEPS microscopy.
FaBSR: a method for cluster failure prediction based on Bayesian serial revision and an application to LANL cluster
Authors: Liu Qiang , Zhou Jinglun , Jin Guang , Sun Quan , Xi Min
Published: September 2010

Accurate failure number prediction of Repairable Large‐scale Long‐running Computing (RLLC) cluster systems is a challenge because of the reparability and large scale of the system. Furthermore, the variational failure rate derived from system maintenance yields a small sample problem, that is, the failure numbers observed from different time phases do not belong to the same population. To address the challenge, a general Bayesian serial revision prediction method (FaBSR) is proposed on the basis of the Time Series and Bootstrap approaches, and it can determine the distribution of failure number, analyze the variation trend of failure rate and accurately predict the failure number. To demonstrate the performance gains of the method, the data of Los Alamos National Laboratory (LANL) cluster system are used as a typical RLLC system to do extensive experiments. And experimental results show that the prediction accuracy of FaBSR is 80.4%, improved by more than 4% compared with other existing methods. Copyright © 2010 John Wiley & Sons, Ltd.
CHARMM‐based parameterization of neutral articaine—A widely used local anesthetic
Authors: Prates Érica T. , Souza Paulo C. T. , Pickholz Mónica , Skaf Munir S.
Published: September 2010

We present a set of CHARMM‐based parameters of molecular mechanics force field for neutral articaine (ATC), a potent and widely used local anesthetic in medical and dental applications. Partial atomic charges and effective torsion potentials around four chemical bonds, not available in CHARMM for this molecule, were obtained from quantum chemical calculations. The newly parameterized model was evaluated by examining the behavior of ATC in water and in a phospholipid bilayer using molecular dynamics simulations. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
The quantum‐chemical study of organic octupolar chromophore triaminotrinitrobenzene and the dimer: Topological analysis and nonlinear optical characteristics
Authors: Balakina Marina Yu. , Fominykh Olga D.
Published: September 2010

The nonempirical calculations of the structure and molecular polarizabilities of octupolar 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) molecule and2TATBdimer, formed of two chromophores through H‐bonding between Oxygens of nitro groups and hydrogens of amino groups of the neighboring molecule, were calculated by TDHF/aug‐cc‐pVDZ′ method. The characterization of2TATBformation is carried out in the framework of topologicalAtoms in Moleculesapproach. The analysis of electron charge density distribution has given evidence to the existence of two equivalent intermolecular NH…O bonds with the bond length of 2.458 Å; the intramolecular H‐bonds between oxygens and hydrogens of alternating nitro‐ and amino groups are also detected. The study of the solvent effect on theTATBelectric properties, performed in the framework of conventional polarizable continuum model, demonstrated weak dependence of molecular polarizabilities on the solvent polarity. The polarizability of2TATBdimer is nearly twice as large as that ofTATB, whereas the modulus of the first hyperpolarizability of2TATBis ∼2.3 times greater than that ofTATB, thus exhibiting the cooperative effect. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Helium‐fullerene pair interactions: An ab initio study by perturbation theory and coupled cluster methods
Authors: Varandas A. J. C.
Published: September 2010

Cuts of the interaction potentials between He and CN (N = 20, 36), calculated and extrapolated to the one‐electron complete basis set limit with Møller–Plesset perturbation theory, have been utilized to obtain extrapolated curves with coupled cluster singles and doubles theory. Calculations are also reported for HeC60 at the Møller–Plesset level with the cc‐pVDZ basis set, and an a priori relationship suggested that relates the well depth of such dimers to the number of C atoms. The predicted van der Waals attributes conform with empirical data, which can be rationalized as a manifestation of the Born–Oppenheimer approximation. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Phenotype of five cases of prenatally diagnosed campomelic dysplasia harboring novel mutations of the SOX9 gene
Authors: Gentilin B. , Forzano F. , Bedeschi M. F. , Rizzuti T. , Faravelli F. , Izzi C. , Lituania M. , Rodriguez‐Perez C. , Bondioni M. P. , Savoldi G. , Grosso E. , Botta G. , Viora E. , Baffico A. M. , Lalatta F.
Published: September 2010

Objectives

Campomelic dysplasia is a rare congenital skeletal disorder characterized by bowing of the long bones and a variety of other skeletal and extraskeletal defects, many of which can now be identified prenatally using advanced ultrasound equipment. The disorder is caused by mutations in SRY‐box 9 (SOX9), a gene that is abundantly expressed in chondrocytes as well as in other tissues. However, the correlation between genotype and phenotype is still unclear. We report five cases of prenatally detected campomelic dysplasia in which the diagnosis was confirmed by molecular analysis.

Methods

Ultrasound examinations were performed between 12 and 32 weeks. Standard fetal biometric measurements were obtained. Fetal sex was determined sonographically and confirmed by chromosomal analysis. Genomic DNA was obtained in four cases before termination of pregnancy from chorionic villi or amniocytes and in one case postnatally from peripheral blood.

Results

Skeletal dysplasia, most often limb shortening and bowed femora, was observed in one case in the first trimester, in three cases in the second trimester and in one case, presenting late for antenatal care, in the third trimester. Four of the pregnancies were terminated and one was carried to term. Postmortem/postnatal physical and radiographic examinations confirmed the presence of anomalies characteristic of campomelic dysplasia. A de novo mutation in the SOX9 gene was detected in all four cases that underwent termination. The father of the proband in the case that went to term was a carrier of a somatic mosaic mutation without clinical or radiographic signs of campomelic dysplasia.

Conclusions

It is likely that the integrated expertise of ultrasonographers, obstetricians, pediatricians and clinical geneticists will markedly improve the likelihood of accurate prenatal clinical diagnoses of campomelic dysplasia. This will, in turn, encourage more specific molecular testing and facilitate comprehensive genetic counseling. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Queue length aware power control for delay‐ constrained communication over fading channels
Authors: Li Xiaochen , Dong Xihua , Wu Dapeng
Published: September 2010

In this paper, we study efficient power control schemes for delay sensitive communication over fading channels. Our objective is to find a power control law that optimizes the link layer performance, specifically, minimizes the packet drop probability, subject to a long‐term average power constraint. We assume the buffer at the transmitter is finite; hence packet drop happens when the buffer is full. The fading channel under our study has a continuous state, e.g., Rayleigh fading. Since the channel state space is continuous, dynamic programming is not applicable for power control. In this paper, we propose a sub‐optimal power control law based on a parametric approach. The proposed power control scheme tries to minimize the packet drop probability by considering the queue length, i.e., reducing the probability of those queue‐length states that will cause full buffer. Simulation results show that our proposed power control scheme reduces the packet drop probability by one or two orders of magnitude, compared to the time domain water filling (TDWF) and the truncated channel inversion (TCI) power control. Copyright © 2010 John Wiley & Sons, Ltd.
Two cases of ectopic ovary and one case of potential ectopic ovary
Authors: Nishio Eiji , Hirota Yutaka , Yasue Akira , Nishizawa Haruki , Tsukada Kazuhiko , Udagawa Yasuhiro
Published: September 2010

Ectopic ovary is a rare gynecologic entity. A variety of synonymous terms such as ectopic ovary, supernumerary ovary, accessory ovary, and autoamputation of the ovary have been used to describe this condition. The etiology for ectopic ovary has not been elucidated, but several mechanisms have been proposed. They are categorized as either congenital (embryologically derived) or acquired. This report presents two cases of ectopic ovary resulting from different causes and one case of potential ectopic ovary.
Discussion of ‘First finds of problematic Ediacaran fossil Gaojiashania in Siberia and its origin’
Authors: Cai Yaoping , Hua Hong , Zhuravlev Andrey Yu. , Gámez Vintaned José Antonio , Ivantsov Andrey Yu.
Published: September 2010

Y. Cai & H. Hua comment: Zhuravlev, Gámez Vintaned & Ivantsov (2009) reported the problematic Ediacaran fossil Gaojiashania annulucosta in Siberia and they considered that this is the first find of Gaojiashania outside China, since Gaojiashania had previously only been reported from the Gaojiashan Member of the middle Dengying Formation in the Ningqiang area, southern Shaanxi Province, South China. However, we believe that the so-called Siberian Gaojiashania was mis-identified, and what was described as Gaojiashania annulucosta by Zhuravlev, Gámez Vintaned & Ivantsov (2009) is more appropriately ascribed to Shaanxilithes ningqiangensis, another problematic Ediacaran fossil that has also been known from the Gaojiashan Member in Shaanxi Province of South China (Chen, Chen & Lao, 1975; Xing et al. 1984), as well as the stratigraphically equivalent Taozichong Formation in Guizhou Province (Hua, Chen & Zhang, 2004) and the Jiucheng Member (Dengying Formation) in Yunnan Province of South China (Zhu & Zhang, 2005), the Zhoujieshan Formation in Qinghai Province (Shen et al. 2007), and the Zhengmuguan Formation in Ningxia Hui Autonomous Region of North China (Shen et al. 2007).
Brazil and ‘Latin America’
Authors: BETHELL LESLIE
Published: September 2010

This essay, part history of ideas and part history of international relations, examines Brazil's relationship with Latin America in historical perspective. For more than a century after independence, neither Spanish American intellectuals nor Spanish American governments considered Brazil part of ‘América Latina’. For their part, Brazilian intellectuals and Brazilian governments only had eyes for Europe and increasingly, after 1889, the United States, except for a strong interest in the Río de la Plata. When, especially during the Cold War, the United States, and by extension the rest of the world, began to regard and treat Brazil as part of ‘Latin America’, Brazilian governments and Brazilian intellectuals, apart from some on the Left, still did not think of Brazil as an integral part of the region. Since the end of the Cold War, however, Brazil has for the first time pursued a policy of engagement with its neighbours – in South America.
Improving the Interpretability of the Variances of Latent Variables by Uniform and Factor-Specific Standardizations of Loadings
Authors: Schweizer Karl
Published: September 2010

The variances of latent variables are presented as statistics that support the evaluation of a model in confirmatory factor analysis. Appropriate standardization even improves the benefit of investigating variances. The variances integrate the information concerning the individual loadings and are associated with an error probability. The estimation of the variances of latent variables requires the estimation of the loadings in the first step and their replacement by constraints according to the estimates in the second step. Uniform or factor-specific standardization is necessary for achieving comparability of the variances. The usefulness of standardization is demonstrated in models from optimism research. Three ways of standardization were considered: uniform standardization, factor-specific standardization, and standardization by setting one loading equal to one. Generally valid results were achieved by uniform standardization. If some loadings were set equal to zero, factor-specific standardization even yielded better results. The results of the remaining way were very specific.
Apparent seasonal cycle in isotopic discrimination of carbon in the atmosphere and biosphere due to vapor pressure deficit
Authors: Ballantyne A. P. , Miller J. B. , Tans P. P.
Published: September 2010

We explore seasonal variability in isotopic fractionation by analyzing observational data from the atmosphere and the biosphere, as well as simulated data from a global model. Using simulated values of atmospheric CO2 and its carbon isotopic composition, we evaluated different methods for specifying background concentrations when calculating the isotopic signature of source CO2 (δs) to the atmosphere. Based on this evaluation, we determined that free troposphere measurements should be used when available as a background reference when calculating δs from boundary layer observations. We then estimate the seasonal distribution of δs from monthly climatologies derived from several atmospheric sampling sites. This approach yields significant seasonal variations in δs with more enriched values during the summer months that exceed the uncertainty of δs estimated for any given month. Intra‐annual measurements of δ13C in the cellulose of Pinus taeda growing in the southeastern U.S. also reveal seasonal isotopic variations that are consistent in phase but not necessarily amplitude with atmospherically derived estimates of δs. Coherent seasonal patterns in δs inferred from the atmosphere and observed in the biosphere were not consistent with the seasonal isotopic discrimination simulated by a commonly used biosphere model. However, δs seasonality consistent with observations from the atmosphere and biosphere was retrieved with a revised biosphere model when stomatal conductance, and thus isotopic discrimination, was allowed to vary in response to vapor pressure deficit rather than relative humidity. Therefore, in regions where vapor pressure deficit and relative humidity are positively covariant over the growth season, such as the sub‐tropics, different stomatal conductance models may yield very different estimates of CO2 and H2O exchange between the biosphere and atmosphere.
Distribution of diverse nitrogen fixers in the global ocean
Authors: Monteiro F. M. , Follows M. J. , Dutkiewicz S.
Published: September 2010

We employ a global three‐dimensional model to simulate diverse phytoplanktonic diazotrophs (nitrogen fixers) in the oceans. In the model, the structure of the marine phytoplankton community self‐assembles from a large number of potentially viable physiologies. Amongst them, analogs ofTrichodesmium, unicellular diazotrophs and diatom‐diazotroph associations (DDA) are successful and abundant. The simulated biogeography and nitrogen fixation rates of the modeled diazotrophs compare favorably with a compilation of published observations, which includes both traditional and molecular measurements of abundance and activity of marine diazotrophs. In the model, the diazotroph analogs occupy warm subtropical and tropical waters, with higher concentrations and nitrogen fixation rates in the tropical Atlantic Ocean and the Arabian Sea/Northern Indian Ocean, and lower values in the tropical and subtropical South Pacific Ocean. The three main diazotroph types typically co‐exist in the model, althoughTrichodesmiumanalogs dominate the diazotroph population in much of the North and tropical Atlantic Ocean and the Arabian Sea, while unicellular‐diazotroph analogs dominate in the South Atlantic, Pacific and Indian oceans. This pattern reflects the relative degree of nutrient limitation by iron or phosphorus. The model suggests in addition that unicellular diazotrophs could add as much new nitrogen to the global ocean asTrichodesmium.
Propagation of whistler mode waves with a modulated frequency in the magnetosphere
Authors: Streltsov A. V. , Gołkowski M. , Inan U. S. , Papadopoulos K. D.
Published: September 2010

This paper presents results from experimental and numerical studies of the propagation of whistler mode waves in the Earth's magnetosphere. An experiment conducted at the High Frequency Active Auroral Research Program (HAARP) on 16 March 2008 demonstrates that ionospherically generated waves with particular frequency‐time formats are amplified on their pass from HAARP to the conjugate location in the South Pacific Ocean more efficiently than waves with a constant frequency. Numerical simulations of a one‐dimensional electron magnetohydrodynamics (MHD) model in the dipole magnetic field geometry reveal that the amplification takes place more efficiently when the frequency of the whistler mode waves (in the frequency range from 0.5 to 1.0 kHz) changes in the equatorial magnetosphere with the rate from 0.25 to 0.47 kHz/s. The maximum amplification occurs when this rate is 0.33 kHz/s and no/very little amplification is observed when this gradient is equal to 0 or when it is larger than 0.78 kHz/s.
A comparison of the effectiveness of 6S and SMAC in correcting for atmospheric interference of Meteosat Second Generation images
Authors: Proud S. R. , Fensholt R. , Rasmussen M. O. , Sandholt I.
Published: September 2010

Atmospheric perturbations are a large source of uncertainty in remotely sensed imagery of the Earth's surface. This paper explores the effectiveness of the simplified method for atmospheric correction (SMAC) in reducing the effects of these perturbations in images of the African Continent gathered by the Spinning Enhanced Visible & InfraRed Imager (SEVIRI) aboard Meteosat Second Generation (MSG). In order to examine the accuracy of the SMAC we compare its results to those computed by the Second Simulation of the Satellite Signal in the Solar Spectrum (6SV1.1), a highly accurate radiative transfer code, for a wide range of atmospheric conditions. We find that the SMAC does not offer a high level of accuracy under many sets of atmospheric conditions with under 20% of observations in channels 1 and 2 providing a relative error of less than 10% when compared to 6SV1.1. Those observations involving medium‐to‐high solar or viewing zenith angles (greater than 40°) or in areas with a high ozone or water vapor content (greater than 0.2 cm/atm and 1.5 gm/cm2 for ozone and water vapor respectively) returning a particularly high relative error. Nevertheless, as the SMAC is up to 3000 times faster in processing a SEVIRI scene than 6SV1.1 it is still a useful atmospheric correction tool, particularly as a majority of the differences between the SMAC and 6S appear straightforward to correct for.
Reduced North Atlantic Central Water formation in response to early Holocene ice‐sheet melting
Authors: Bamberg Audrey , Rosenthal Yair , Paul André , Heslop David , Mulitza Stefan , Rühlemann Carsten , Schulz Michael
Published: September 2010

Central waters of the North Atlantic are fundamental for ventilation of the upper ocean and are also linked to the strength of the Atlantic Meridional Overturning Circulation (AMOC). Here, we show based on benthic foraminiferal Mg/Ca ratios, that during times of enhanced melting from the Laurentide Ice Sheet (LIS) between 9.0–8.5 thousand years before present (ka) the production of central waters weakened the upper AMOC resulting in a cooling over the Northern Hemisphere. Centered at 8.54 ± 0.2 ka and 8.24 ± 0.1 ka our dataset records two ∼150‐year cooling events in response to the drainage of Lake Agassiz/Ojibway, indicating early slow‐down of the upper AMOC in response to the initial freshwater flux into the subpolar gyre (SPG) followed by a more severe weakening of both the upper and lower branches of the AMOC at 8.2 ka. These results highlight the sensitivity of regional North Atlantic climate change to the strength of central‐water overturning and exemplify the impact of both gradual and abrupt freshwater fluxes on eastern SPG surface water convection. In light of the possible future increase in Greenland Ice Sheet melting due to global warming these findings may help us to better constrain and possibly predict future North Atlantic climate change.
Lagrangian assessment of simulated surface current dispersion in the coastal ocean
Authors: Ohlmann J. Carter , Mitarai Satoshi
Published: September 2010

A purely Lagrangian assessment of dispersion from modeled surface current trajectories in the coastal ocean is presented. Modeled trajectories come from ROMS simulations for the Southern California Bight during the 1996 through 1999 period. Data are from surface current trajectories collected primarily in the Santa Barbara Channel with CODE style drifters. Distributions of particle positions from trajectories emanating from launch locations within 10 kilometers of the coast throughout the Santa Barbara Channel that advect for one through four days (Lagrangian PDFs) are evaluated descriptively and quantitatively. The two dimensional Kolmogorov‐Smirnov (K‐S) statistical test for comparing discrete sampled data with a known probability distribution is the quantitative basis. In general, dispersion distributions from observations are similar to Lagrangian PDFs computed from modeled trajectories and the K‐S statistic quantifies this accordingly. A few specific regions of poor model‐data agreement are indicated and discussed. The purely Lagrangian assessment, elucidates an improved understanding of model performance and ocean circulation beyond that offered in a Eulerian sense, and is necessary when modeled trajectories are utilized for applied oceanographic and marine ecology problems.
Ionosphere around equinoxes during low solar activity
Authors: Liu Libo , He Maosheng , Yue Xin'an , Ning Baiqi , Wan Weixing
Published: September 2010

The seasonal behaviors of the ionosphere have been investigated for several decades, but the differences of the ionosphere between the March and September equinoxes are still an open question. In this analysis we utilize the data of ionospheric electron density (Ne) profiles from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission radio occultation measurements, total electron density (TEC) from TOPEX and Jason‐1, and TEC from Global Positioning System (GPS) receivers as well as global ionosonde measurements of the F2 layer peak electron density (NmF2) to investigate the behaviors of the daytime ionosphere around equinoxes during low solar activity (LSA). The analysis reveals that during LSA the equinoctial asymmetry in ionospheric plasma density is mainly a low‐latitude phenomenon. The differences of equinoctial TEC and NmF2 have considerable amplitudes at low latitudes in both hemispheres and less significant at higher latitudes. With increasing altitude, the asymmetry in COSMIC Ne becomes weaker in the Southern Hemisphere, and the northern pronounced asymmetry regions move toward the magnetic equator. The ionospheric equinoctial asymmetry may be considered as a manifestation of the annual variation, whose annual phase significantly shifts away from the solstices. The F layer peak height (hmF2) extracted from COSMIC Ne profiles also shows an equinoctial asymmetry at low latitudes, indicating the existence of equinoctial differences in low‐latitude neutral winds, specifically in the Northern Hemisphere. It reveals that, besides the important effect of the neutral wind, other processes should play roles in the forming of the observed equinoctial asymmetry in the ionosphere.
Nine years of mass transport data in the eastern boundary of the North Atlantic Subtropical Gyre
Authors: Fraile‐Nuez Eugenio , Machín Francisco , Vélez‐Belchí Pedro , López‐Laatzen Federico , Borges Rafael , Benítez‐Barrios Verónica , Hernández‐Guerra Alonso
Published: September 2010

One of the longest current meter time series in the Lanzarote Passage in the eastern boundary of the North Atlantic Subtropical Gyre has been used to determine and quantify the 9‐year mean transport, the inter‐annual and seasonal mass transport variability for the three water masses present in the area. Results show North Atlantic Central Water (NACW) flowing southward in the upper levels with a mean mass transport of −0.81 ± 1.48 Sv, Antarctic Intermediate Water (AAIW) flowing northward at intermediate levels with a mean transport of +0.09 ± 0.57 Sv and Mediterranean Water (MW) flowing southward in the deep part of the passage with a mean transport of −0.05 ± 0.17 Sv. Harmonic and wavelet analysis show the presence of a seasonal pattern in the passage for the three water masses. A maximum southward transport in winter and spring has been observed for the NACW followed by a minimum in summer and fall. Near zero values during winter and spring are found for AAIW, with a maximum northward value in summer and a negative value in fall, when this water mass reverses its flow. MW has a similar seasonal pattern to NACW. The vertical structure in the Lanzarote Passage can be approximated by four significant oscillatory modes which cumulatively explain 86.4% of the variance. The strong transport fluctuation found at the seasonal and inter‐annual timescales demonstrates that the Eastern Boundary Current transport has a strong impact on meridional overturning estimates, thus indicating that to understand Meridional Overturning Circulation variability, these transport estimates at the eastern Atlantic margin are necessary.
Premonsoon aerosol characterization and radiative effects over the Indo‐Gangetic Plains: Implications for regional climate warming
Authors: Gautam Ritesh , Hsu N. Christina , Lau K.‐M.
Published: September 2010

The Himalayas have a profound effect on the South Asian climate and the regional hydrological cycle, as it forms a barrier for the strong monsoon winds and serves as an elevated heat source, thus controlling the onset and distribution of precipitation during the Indian summer monsoon. Recent studies have suggested that radiative heating by absorbing aerosols, such as dust and black carbon over the Indo‐Gangetic Plains (IGP) and slopes of the Himalayas, may significantly accelerate the seasonal warming of the Hindu Kush–Himalayas–Tibetan Plateau (HKHT) and influence the subsequent evolution of the summer monsoon. This paper presents a detailed characterization of aerosols over the IGP and their radiative effects during the premonsoon season (April‐May‐June) when dust transport constitutes the bulk of the regional aerosol loading, using ground radiometric and spaceborne observations. During the dust‐laden period, there is a strong response of surface shortwave flux to aerosol absorption indicated by the diurnally averaged forcing efficiency of −70 Wm−2 per unit optical depth. The simulated aerosol single‐scattering albedo, constrained by surface flux and aerosol measurements, is estimated to be 0.89 ± 0.01 (at ∼550 nm) with diurnal mean surface and top‐of‐atmosphere forcing values ranging from −11 to −79.8 Wm−2 and +1.4 to +12 Wm−2, respectively, for the premonsoon period. The model‐simulated solar heating rate profile peaks in the lower troposphere with enhanced heating penetrating into the middle troposphere (5–6 km), caused by vertically extended aerosols over the IGP with peak altitude of ∼5 km as indicated by spaceborne Cloud‐Aerosol Lidar with Orthogonal Polarization observations. On a long‐term climate scale, our analysis, on the basis of microwave satellite measurements of tropospheric temperatures from 1979 to 2007, indicates accelerated annual mean warming rates found over the Himalayan–Hindu Kush region (0.21°C/decade ± 0.08°C/decade) and underscores the potential role of enhanced aerosol solar absorption in the maximum warming localized over the western Himalayas (0.26°C/decade ± 0.09°C/decade) that significantly exceed the entire HKHT and global warming rates. We believe the accelerated warming rates reported here are critical to both the South Asian summer monsoon and hydro‐glaciological resource variability in the Himalayan–Hindu Kush snowpack and therefore to the densely populated downstream regions.
Sulfide induces phosphate release from polyphosphate in cultures of a marine Beggiatoa strain
Authors: Brock Jörg , Schulz-Vogt Heide N
Published: September 2010

Sulfur bacteria such as Beggiatoa or Thiomargarita have a particularly high capacity for storage because of their large size. In addition to sulfur and nitrate, these bacteria also store phosphorus in the form of polyphosphate. Thiomargarita namibiensis has been shown to release phosphate from internally stored polyphosphate in pulses creating steep peaks of phosphate in the sediment and thereby inducing the precipitation of phosphorus-rich minerals. Large sulfur bacteria populate sediments at the sites of recent phosphorite formation and are found as fossils in ancient phosphorite deposits. Therefore, it can be assumed that this physiology contributes to the removal of bioavailable phosphorus from the marine system and thus is important for the global phosphorus cycle. We investigated under defined laboratory conditions which parameters stimulate the decomposition of polyphosphate and the release of phosphate in a marine Beggiatoa strain. Initially, we tested phosphate release in response to anoxia and high concentrations of acetate, because acetate is described as the relevant stimulus for phosphate release in activated sludge. To our surprise, the Beggiatoa strain did not release phosphate in response to this treatment. Instead, we could clearly show that increasing sulfide concentrations and anoxia resulted in a decomposition of polyphosphate. This physiological reaction is a yet unknown mode of bacterial polyphosphate usage and provides a new explanation for high phosphate concentrations in sulfidic marine sediments.
Assessment of Atrial Electromechanical Delay by Tissue Doppler Echocardiography in Obese Subjects
Authors: Yagmur Julide , Cansel Mehmet , Acikgoz Nusret , Ermis Necip , Yagmur Murat , Atas Halil , Tasolar Hakan , Karakus Yasin , Pekdemir Hasan , Ozdemir Ramazan
Published: September 2010

Our aim was to evaluate whether atrial electromechanical delay measured by tissue Doppler imaging (TDI), which is an early predictor of atrial fibrillation (AF) development, is prolonged in obese subjects. A total of 40 obese and 40 normal‐weight subjects with normal coronary angiograms were included in this study. P‐wave dispersion (PWD) was calculated on the 12‐lead electrocardiogram (ECG). Systolic and diastolic left ventricular (LV) functions, inter‐ and intra‐atrial electromechanical delay were measured by TDI and conventional echocardiography. Inter‐ and intra‐atrial electromechanical delay were significantly longer in the obese subjects compared with the controls (44.08 ± 10.06 vs. 19.35 ± 5.94 ms and 23.63 ± 6.41 vs. 5.13 ± 2.67 ms, P < 0.0001 for both, respectively). PWD was higher in obese subjects (53.40 ± 5.49 vs. 35.95 ± 5.93 ms, P < 0.0001). Left atrial (LA) diameter, LA volume index and LV diastolic parameters were significantly different between the groups. Interatrial electromechanical delay was correlated with PWD (r = 0.409, P = 0.009), high‐sensitivity C‐reactive protein (hsCRP) levels (r = 0.588, P < 0.0001). Interatrial electromechanical delay was positively correlated with LA diameter, LA volume index, and LV diastolic function parameters consisting of mitral early wave (E) deceleration time (DT) and isovolumetric relaxation time (IVRT; r = 0.323, P = 0.042; r = 0.387, P = 0.014; r = 0.339, P = 0.033; r = 0.325, P = 0.041; respectively) and, negatively correlated with mitral early (E) to late (A) wave ratio (E/A) (r = −0.380, P = 0.016) and myocardial early‐to‐late diastolic wave ratio (Em/Am) (r = −0.326, P = 0.040). This study showed that atrial electromechanical delay is prolonged in obese subjects. Prolonged atrial electromechanical delay is due to provoked low‐grade inflammation as well as LA enlargement and early LV diastolic dysfunction in obese subjects.
ADRB2 Haplotype Is Associated With Glucose Tolerance and Insulin Sensitivity in Obese Postmenopausal Women
Authors: Prior Steven J. , Goldberg Andrew P. , Ryan Alice S.
Published: September 2010

The β2‐adrenergic receptor (ADRB2) mediates obesity, cardiorespiratory fitness, and insulin resistance. We examined the hypothesis that ADRB2 Arg16Gly‐Gln27Glu haplotype is associated with body composition, glucose tolerance, and insulin sensitivity in obese, postmenopausal women. Obese (>35% body fat), postmenopausal (age 45–75 years) women (n = 123) underwent genotyping, dual‐energy X‐ray absorptiometry, and computed tomography scans, exercise testing (VO2max), 2‐h oral glucose tolerance tests (OGTTs), and hyperinsulinemic‐euglycemic clamps (80 mU/m2/min). Analysis of covariance (ANCOVA) tested for differences among haplotypes, with race, % body fat, and VO2max as covariates. We found that ADRB2 haplotype was independently associated with % body fat, abdominal fat distribution, VO2max, insulin sensitivity (M/ΔInsulin), and glucose tolerance (ANOVA, P < 0.05 for all). Women homozygous for Gly16–Gln27 haplotype had the highest % body fat (52.7 ± 1.9%), high abdominal fat, low M/ΔInsulin (0.49 ± 0.08 mg/kg/min/pmol/l/102), and impaired glucose tolerance (IGT) during an OGTT (G120 = 10.2 ± 0.9 mmol/l). Women homozygous for Gly16–Glu27 haplotype also had low M/ΔInsulin (0.51 ± 0.05 mg/kg/min/pmol/l/102) and IGT (G120 = 8.2 ± 0.7 mmol/l). Subjects with Arg16–Gln27/Gly16–Gln27 haplotype combination had the highest VO2max (1.84 ± 0.07 l/min) and M/ΔInsulin (0.7 ± 0.04 mg/kg/min/pmol/l/102), and normal glucose tolerance (G120 = 6.4 ± 0.4 mmol/l), despite being obese. These data show associations of the ADRB2 Arg16Gly‐Gln27Glu haplotype with VO2max and body composition, and an independent association with glucose metabolism, which persists after controlling for body composition and fitness. This suggests that ADRB2 haplotypes may mediate insulin action, glucose tolerance, and potentially risk for type 2 diabetes mellitus (T2DM) in obese, postmenopausal women.
FFA‐Induced Adipocyte Inflammation and Insulin Resistance: Involvement of ER Stress and IKKβ Pathways
Authors: Jiao Ping , Ma Jie , Feng Bin , Zhang Hao , Alan‐Diehl J. , Eugene‐Chin Y. , Yan Weiqun , Xu Haiyan
Published: September 2010

Free‐fatty acids (FFAs) are well‐characterized factor for causing production of inflammatory factors and insulin resistance in adipocytes. Using cultured adipocytes, we demonstrate that FFAs can activate endoplasmic reticulum (ER) stress pathway by examination of ER stress sensor activation and marker gene expression. Chemical chaperone tauroursodeoxycholic acid (TUDCA) can reduce FFA‐induced adipocyte inflammation and improve insulin signaling whereas overexpression of spliced X‐box protein 1 (XBP‐1s) only attenuates FFA‐induced inflammation. PKR‐like eukaryotic initiation factor 2α kinase (PERK) is one of the three major ER stress sensor proteins and deficiency of PERK alleviates FFA‐induced inflammation and insulin resistance. The key downstream target of FFA‐induced ER stress is IκB kinase β (IKKβ), a master kinase for regulating expression of inflammatory genes. Deficiency of PERK attenuates FFA‐induced activation of IKKβ and deficiency of IKKβ alleviates FFA‐induced inflammation and insulin resistance. Consistently, overexpression of IKKβ in 3T3‐L1 CAR adipocytes causes inflammation and insulin resistance. In addition, IKKβ overexpression has profound effect on adipocyte lipid metabolism, including inhibition of lipogenesis and promotion of lipolysis. Furthermore, increased endogenous IKKβ expression and activation is also observed in isolated primary adipocytes from mice injected with lipids or fed on high‐fat diet (HFD) acutely. These results indicate that ER stress pathway is a key mediator for FFA‐induced inflammation and insulin resistance in adipocytes with PERK and IKKβ as the critical signaling components.
Face dependence of mechanical properties of a single ZnO nano/microrod
Authors: Yan Xiaodong , Dickinson Michelle , Schirer Jeffrey P. , Zou Chongwen , Gao Wei
Published: September 2010

The mechanical properties of the single ZnO rod were studied using nanoindentation. The hardness and Young’s modulus of the polar (0001) and nonpolar (011¯0) faces were tested and the results demonstrate a face dependence variation in both properties. The mechanical behavior of the ZnO nano/microrod is discussed in conjunction with its morphology, structure, and defect effects.
Limits for n-type doping in In2O3 and SnO2: A theoretical approach by first-principles calculations using hybrid-functional methodology
Authors: Ágoston Péter , Körber Christoph , Klein Andreas , Puska Martti J. , Nieminen Risto M. , Albe Karsten
Published: September 2010

The intrinsic n-type doping limits of tin oxide (SnO2) and indium oxide (In2O3) are predicted on the basis of formation energies calculated by the density-functional theory using the hybrid-functional methodology. The results show that SnO2 allows for a higher n-type doping level than In2O3. While n-type doping is intrinsically limited by compensating acceptor defects in In2O3, the experimentally measured lower conductivities in SnO2-related materials are not a result of intrinsic limits. Our results suggest that by using appropriate dopants in SnO2 higher conductivities similar to In2O3 should be attainable.