bluuebunny/crossref_metadata_2025 huggingface dataset:
Real‐time study of protein adsorption on thin nanocrystalline diamond
Authors: Grieten L. , Janssens S. D. , Ethirajan A. , Bon N. Vanden , Ameloot M. , Michiels L. , Haenen K. , Wagner P.
Published: September 2011

The study of protein adsorption on solid surfaces is interesting for theoretical and practical bio‐analytical sensing applications. In this work we combine electrochemical impedance spectroscopy, enzyme linked immunosorbent assay, and fluorescence microscopy with thin boron doped nanocrystalline diamond films to address and study the adsorption behavior of globular proteins (antibodies) on hydrophobic and hydrophilic diamond surfaces. A powerful combination of time resolved impedance spectroscopy and data modeling with equivalent circuits allow a detailed insight in the protein behavior at an interface. It is found that hydrogenated diamond is greatly favorable for impedimetric read‐out but causes slight conformational loss of the protein structure and therefore also its biological activity. The oxidized surface allows faster adsorption and a high biological activity but results in smaller impedimetric response.
Sputter‐deposited Ga–Sn–Zn–O thin films for transparent thin film transistors
Authors: Kim Dong‐Ho , Kim Hey‐Ri , Kwon Jung‐Dae , Lee Gun‐Hwan , Lee Hee Sung , Im Seongil
Published: September 2011

Ga–Sn–Zn–O (GTZO) thin films were prepared on glass substrates at 100 °C by co‐sputtering of Ga‐doped ZnO and SnO2 targets. Characteristic properties of the films were investigated with varying oxygen gas content in the sputtering ambient. Whereas amorphous GTZO films were prepared with pure Ar sputtering, polycrystalline films were obtained with the addition of oxygen gas. With a proper mixing ratio of sputtering gases, O2/(Ar + O2) ∼2%, we could obtain GTZO films with good performances as an active channel material in thin film transistor (TFT); i.e, field effect mobility of 12.2 cm2 V−1 s−1, on/off current ratio of 109, and subthreshold voltage swing of 0.46 V decade−1.
Controlling out‐of‐plane deformations of graphene nanobridges
Authors: Nakajima T. , Shintani K.
Published: September 2011

Graphene nanoribbons (GNRs) can be applied to transistors, mass sensors, and dust detectors. Suspended GNRs which connect terminals in electronic devices like bridges can be treated as edge‐constrained GNRs. In this paper, edge‐constrained GNRs of various sizes and initial strains are studied using molecular dynamics (MD) simulations. To induce strain in GNRs, bond lengths between carbon atoms of the initial configurations of GNR models are varied. The bond length of the energetically stable GNRs is estimated at 1.47 Å. At this bond length, GNRs obviously change the tendencies of their energies, amplitudes, and deformations. The relationships between the out‐of‐plane deformations and the sizes of GNRs, and between the out‐of‐plane deformations and strains of GNRs are studied. Under compressive strain, the out‐of‐plane deformation of GNRs is dominantly caused by buckling. The amplitude of the buckling decreases as GNRs elongate. On the other hand, under tensile strain, the out‐of‐plane deformation of GNRs is caused by ripples and thermal vibrations. The ripples show regular patterns. It is suggested we can control the amplitudes of the out‐of‐plane deformations and ripple patterns of GNRs by adjusting their strain.
Direct graphene growth on insulator
Authors: Lippert Gunther , Dabrowski Jarek , Lemme Max , Marcus Charles , Seifarth Olaf , Lupina Grzegorz
Published: September 2011

Fabrication of graphene devices is often hindered by incompatibility between the silicon technology and the methods of graphene growth. Exfoliation from graphite yields excellent films but is good mainly for research. Graphene grown on metal has a technological potential but requires mechanical transfer. Growth by SiC decomposition requires a temperature budget exceeding the technological limits. These issues could be circumvented by growing graphene directly on insulator, implying Van der Waals growth. During growth, the insulator acts as a support defining the growth plane. In the device, it insulates graphene from the Si substrate. We demonstrate planar growth of graphene on mica surface. This was achieved by molecular beam deposition above 600 °C. High resolution Raman scans illustrate the effect of growth parameters and substrate topography on the film perfection. Ab initio calculations suggest a growth model. Data analysis highlights the competition between nucleation at surface steps and flat surface. As a proof of concept, we show the evidence of electric field effect in a transistor with a directly grown channel.

magnified image

Energetic carbon atoms impinge onto the mica. Few‐layer graphene nucleates at step edges and at chemisorbed carbon atoms (black circles). At temperatures above 600 °C, nano‐sized graphene flakes can slide freely to coalesce into a graphene film.
Comprehensive characterization of an individual carbon nanotube transport device
Authors: Frielinghaus Robert , Goß Karin , Trellenkamp Stefan , Houben Lothar , Schneider Claus M. , Meyer Carola
Published: September 2011

We present a comprehensive characterization of an individual multiwalled carbon nanotube transport device combining electron microscopy and Raman spectroscopy with electrical measurements. Each method gives complementary information that mutually help to interpret each other. A sample design that allows for combining these investigation methods on individual carbon nanotube devices is introduced. This offers a direct correlation of transport features and shifts of Raman modes with structural properties as, e.g. the contact interface and the morphology of the nanotube.
Electric dipole moments and polarizabilities of small Bin (n = 2–24, 40, 80) clusters
Authors: Zhang Song , Yuan Hong Kuan , Chen Hong , Kuang An Long , Wu Bo
Published: September 2011

The electric dipole moments (EDMs) and polarizabilities of small Bin (n = 2–24, 40, 80) clusters are investigated by the finite field method within density functional theory (DFT). The results show that both dipole moments and polarizabilities have even–odd oscillation behaviors, and they strongly depend on geometrical structures and electronic structures. High symmetry structure prohibits the occurrence of EDMs on Bi clusters. The increasing polarizabilities of Bi clusters are attributed to the inherent novel chain‐like geometrical evolution, which is significantly different from the characters observed in metal clusters or semiconductor clusters.
Local magnetic switching in patterned permalloy elements by focussed‐MOKE measurements
Authors: Sun Li , Zou Xiao , Zhang Wen , Li Guodong , Zhai Ya , Wu Jing , Xu Yongbing , Zhai Hongru
Published: September 2011

An investigation on the local magnetization processes within patterned permalloy films was performed by means of focussed magneto‐optic Kerr effect (MOKE) measurements, from which local magnetic hysteresis loops of the individual elements were found to be dependent on the separation between the individuals as well as the position in the array. When the separation between elements is larger than the element size, positions of elements in the array is relatively less influential on the behaviour of the magnetic hysteresis loops which are just the contribution of an individual element. When the separation between elements is close to the element size, the magnetic anisotropy shown in the magnetic Kerr loops is affected by the element position indicating that the magnetic interaction should be taken into account, which is also confirmed by the Micromagnetic simulations. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inversion for atmospheric thermodynamical parameters of IASI data in the principal components space
Authors: Masiello G. , Serio C. , Antonelli P.
Published: September 2011

The problem of reducing the dimensionality of infrared atmospheric sounding interferometer (IASI) data space through a suitable transform and performing the retrieval process for thermodynamical parameters within the transformed data space is addressed in this paper. The reduction of dimensionality is performed with the principal components transform, which allows us to represent the full IASI spectrum with a few coefficients of the expansion. This truncated expansion could have a twofold beneficial effect: (i) it could improve the present exploitation and performance of IASI data for the retrieval of temperature and moisture; and (ii) it could save transmission bandwidth, data rate and costs for the dissemination to users of IASI data. A suitable form of the inverse/forward model completely embedded in the transformed space has been derived and applied to simulated and real IASI data. This methodology has allowed us to assess the IASI performance for temperature, water vapor and ozone based on the full IASI spectral coverage. The use of back‐transformed spectral radiances (i.e. the filtered radiances obtained by the truncated expansion) instead of expansion coefficients has also been addressed and assessed. Retrieval exercises performed in simulation and with real observations lead us to conclude that the principal components space‐based inverse approach is potentially superior over the current practice of using sparse channels. Copyright © 2011 Royal Meteorological Society
Toward anharmonic computations of vibrational spectra for large molecular systems
Authors: Barone Vincenzo , Biczysko Malgorzata , Bloino Julien , Borkowska‐Panek Monika , Carnimeo Ivan , Panek Pawel
Published: September 2011

The subtle interplay of several different effects makes the interpretation and analysis of experimental spectra in terms of structural and dynamic characteristics a very challenging task. In this context, theoretical studies can be very helpful, and this is the reason behind the rapid evolution of computational spectroscopy from a highly specialized research field toward a versatile and widespread tool. However, in the case of vibrational spectra of large molecular systems, the most popular approach still relies on a harmonic treatment, because of the difficulty to explore the multidimensional anharmonic potential energy surface. These can be overcome considering that, in many cases, the vibrational transitions are well localized and only some of them are observed experimentally. To this aim, the procedure for the simulation of vibrational spectra of large molecular systems beyond the harmonic approximation is discussed. The quality of system‐specific reduced dimensional anharmonic approaches is first validated by comparison with computations taking into account all modes simultaneously for anisole and glycine. Next, the approach is applied to two larger systems, namely glycine adsorbed on a silicon surface and chlorophyll‐a in solution, and the results are compared with experimental data showing significant improvement over the standard harmonic approximation. Our results show that properly tailored reduced dimension anharmonic approaches stand as feasible routes for state‐of‐the‐art computational spectroscopy studies and allow to take into account both anharmonic and environmental effects on the spectra even for relatively large molecular systems. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Contribution of uniformly 13C‐enriched sterigmatocystin to the study of its pulmonary metabolism
Authors: Cabaret Odile , Puel Olivier , Botterel Françoise , Pean Michel , Bretagne Stéphane , Delaforge Marcel
Published: September 2011

Mycotoxins are secondary metabolites of filamentous fungi which can cause a wide range of systemic effects. Human health effects of inhaled mycotoxins remain poorly documented, despite the large amounts present, associated with air‐borne particles. Among these mycotoxins, sterigmatocystin is one of the most prevalent. Because its chemical structure is close to that of the aflatoxins, we studied its metabolism and its cellular consequences when in contact with the airway epithelium, using the mass spectral signature from the 10% 13C uniformly enriched sterigmatocystin. The metabolism was studied in vitro, using recombinant cytochrome P450s enzymes, and in porcine tracheal epithelial cell (PTEC) primary cultures at an air‐liquid interface. The metabolites were analyzed by high‐performance liquid chromatography coupled with tandem mass spectrometry detection. Expressed enzymes and PTECs were exposed to uniformly 13 C‐enriched sterigmatocystin to confirm the relationship between sterigmatocystin and its metabolites because this isotopic cluster shape is conserved for all metabolites and their product ions. Incubation of sterigmatocystin with recombinant cytochrome P450 1A1 led to the formation of three metabolites identified as monohydroxysterigmatocystin, dihydroxysterigmatocystin and one glutathione adduct, the latter after the formation of a transient intermediate. In the PTEC cultures, sterigmatocystin metabolism resulted in a glucuro‐conjugate. Two other products were detected, a sulfo‐conjugate and a glucuro‐conjugate of hydroxysterigmatocystin upon cytochrome P450 1A1 induction. This is the first study to report sterigmatocystin metabolism in airway epithelium, and it suggests that, contrary to the aflatoxins, sterigmatocystin is mainly detoxified into its conjugates and is unable to produce significant amounts of reactive metabolites in respiratory cells, at least in pigs. Copyright © 2011 John Wiley & Sons, Ltd.
An informed reference prior for between‐study heterogeneity in meta‐analyses of binary outcomes
Authors: Pullenayegum Eleanor M.
Published: September 2011

It is well known that when a Bayesian meta‐analysis includes a small number of studies, inference can be sensitive to the choice of prior for the between‐study variance. Choosing a vague prior does not solve the problem, as inferences can be substantially different depending on the degree of vagueness. Moreover, because the data provide little information on between‐study heterogeneity, posterior inferences for the between‐study variance based on vague priors will tend to be unrealistic. It is thus preferable to adopt a reasonable, informed prior for the between‐study variance. However, relatively little is known about what constitutes a realistic distribution. On the basis of data from the Cochrane Database of Systematic Reviews, this paper describes the distribution of between‐study variance in published meta‐analyses, and proposes some realistic, informed priors for use in meta‐analyses of binary outcomes. It is hoped that these priors will improve the calibration of inferences from Bayesian meta‐analyses. Copyright © 2011 John Wiley & Sons, Ltd.
Resizing Metal‐Coated Nanopores Using a Scanning Electron Microscope
Authors: Chansin Guillaume A. T. , Hong Jongin , Dusting Jonathan , deMello Andrew J. , Albrecht Tim , Edel Joshua B.
Published: September 2011

Electron beam‐induced shrinkage provides a convenient way of resizing solid‐state nanopores in Si3N4 membranes. Here, a scanning electron microscope (SEM) has been used to resize a range of different focussed ion beam‐milled nanopores in Al‐coated Si3N4 membranes. Energy‐dispersive X‐ray spectra and SEM images acquired during resizing highlight that a time‐variant carbon deposition process is the dominant mechanism of pore shrinkage, although granular structures on the membrane surface in the vicinity of the pores suggest that competing processes may occur. Shrinkage is observed on the Al side of the pore as well as on the Si3N4 side, while the shrinkage rate is observed to be dependent on a variety of factors.
A review of methods for evaluation of maturity models for process improvement
Authors: Helgesson Yeni Yuqin Li , Höst Martin , Weyns Kim
Published: September 2011

Maturity models are widely used in process improvement. The users of a maturity model should be confident that the weak points of the assessed processes can be found, and that the most valuable changes are introduced. Therefore, the evaluation of maturity models is an important activity. In this paper, a mapping study of the literature on the evaluation of maturity models is presented. Two databases are searched resulting in a set of relevant papers. The identified papers can be classified according to six categories, namely the maturity model under evaluation, type of evaluation, relation of the evaluators/authors to the maturity model, level of objectivity, main purpose of the paper, and size of study. Further, a framework of different evaluations of maturity models is developed, and the relevant papers are mapped to the framework. Finally, the relevant research on the evaluation of the maturity models in the Capability Maturity Model family is discussed in more detail. The result of this mapping study is a clear overview of how the evaluation of maturity models has been done, and some discussions are provided for further research on the evaluation of commonly used or newly developed maturity models. Copyright © 2011 John Wiley & Sons, Ltd.
Lossless asymmetric single instruction multiple data codec
Authors: Wassenberg Jan
Published: September 2011

This report introduces a new lossless asymmetric single instruction multiple data codec designed for extremely efficient decompression of large satellite images. A throughput in excess of 3GB/s allows decompression to proceed in parallel with asynchronous transfers from fast block devices such as disk arrays. This is made possible by a simple and fast single instruction multiple data entropy coder that removes leading null bits. Our main contribution is a new approach for vectorized prediction and encoding. Unlike previous approaches that treat the entropy coder as a black box, we account for its properties in the design of the predictor. The resulting compressed stream is 1.2 to 1.5 times as large as JPEG‐2000, but can be decompressed 100 times as quickly – even faster than copying uncompressed data in memory. Applications include streaming decompression for out of core visualization. To the best of our knowledge, this is the first entirely vectorized algorithm for lossless compression. Copyright © 2011 John Wiley & Sons, Ltd.
Entwurf und Nachweisführung von Grout‐Verbindungen unter Berücksichtigung der Beanspruchungssituation in Tragstrukturen von Offshore‐Windenergieanlagen
Authors: Scharff Rüdiger , Siems Michael
Published: September 2011

Der folgende Beitrag stellt ein praxisorientiertes Bemessungskonzept für Grout‐Verbindungen von Tragstrukturen für Offshore‐Windenergieanlagen vor. Es werden zylindrische Verbindungen mit Schubrippen betrachtet. Die kombinierte Einwirkung von Biegemomenten und Normalkräften wird in dem Konzept direkt berücksichtigt und die übliche Nachweisführung über empirische Bemessungsformeln verlassen. Die wirklichkeitsnahe Abbildung der physikalischen Effekte in den Kontaktfugen erfolgt in zwei aufeinander abgestimmten Finite‐Elemente‐Modellen. Nach einer detaillierten Betrachtung der auftretenden Tragmechanismen in einer Verbindung ohne Schubrippen werden die vorhandenen physikalischen Effekte beim Vorhandensein von Schubrippen in einem Submodell untersucht. Die daraus gewonnenen Erkenntnisse über die Kraftverteilung zwischen Druckstreben und Reibverbund werden anschließend über vereinfachte Federmodelle in das globale numerische Modell integriert. Auf diese Weise kann mit vertretbarem numerischem Aufwand das reale Tragverhalten einer Grout‐Verbindung mit Schubrippen zuverlässig nachgewiesen werden.

Design of grouted joints of structures for offshore wind turbines taking the loading situation into consideration. The following article presents a practical design concept for grouted joints of structures for offshore wind turbines. Cylindrical connections with shear keys are considered. In this concept the combined action of bending moments and normal forces is directly taken into account thus the usage of empirical design formulas can be omitted. The realistic representation of physical effects in the contact joint is carried out in two complementary finite element models. After a detailed examination of the structural mechanisms that occur in a connection without shear keys, the existing physical effects in the presence of shear keys are examined in a sub model. The knowledge about the force distribution between the struts and the friction stresses is subsequently integrated in the global numerical model using simplified spring models. In this way the design calculations for a grouted joint with shear keys can be carried out with reasonable numerical effort taking into account the real structural behaviour.
Intra‐ and interobserver variability in fetal ultrasound measurements
Authors: Sarris I. , Ioannou C. , Chamberlain P. , Ohuma E. , Roseman F. , Hoch L. , Altman D. G. , Papageorghiou A. T. ,   for the International Fetal and Newborn Growth Consortium for the 21 Century (INTERGROWTH‐21)
Published: September 2011

Objective

To assess intra‐ and interobserver variability of fetal biometry measurements throughout pregnancy.

Methods

A total of 175 scans (of 140 fetuses) were prospectively performed at 14–41 weeks of gestation ensuring an even distribution throughout gestation. From among three experienced sonographers, a pair of observers independently acquired a duplicate set of seven standard measurements for each fetus. Differences between and within observers were expressed in measurement units (mm), as a percentage of fetal dimensions and as gestational age‐specific Z‐scores. For all comparisons, Bland–Altman plots were used to quantify limits of agreement.

Results

When using measurement units (mm) to express differences, both intra‐ and interobserver variability increased with gestational age. However, when measurement of variability took into account the increasing fetal size and was expressed as a percentage or Z‐score, it remained constant throughout gestation. When expressed as a percentage or Z‐score, the 95% limits of agreement for intraobserver difference for head circumference (HC) were ± 3.0% or 0.67; they were ± 5.3% or 0.90 and ± 6.6% or 0.94 for abdominal circumference (AC) and femur length (FL), respectively. The corresponding values for interobserver differences were ± 4.9% or 0.99 for HC, ± 8.8% or 1.35 for AC and ± 11.1% or 1.43 for FL.

Conclusions

Although intra‐ and interobserver variability increases with advancing gestation when expressed in millimeters, both are constant as a percentage of the fetal dimensions or when reported as a Z‐score. Thus, measurement variability should be considered when interpreting fetal growth rates. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasonographic and laboratory markers of metabolic and cardiovascular disease risk in obese women with polycystic ovary syndrome
Authors: Zueff L. F. N. , Martins W. P. , Vieira C. S. , Ferriani R. A.
Published: September 2011

Objective

To evaluate whether the presence of polycystic ovary syndrome (PCOS) alters multiple ultrasonographic and laboratory markers of metabolic and cardiovascular disease risk in obese women without any other health condition that could interfere with combined oral contraceptive (COC) eligibility criteria.

Methods

This was a case–control study evaluating 90 obese women (body mass index (BMI) ≥ 30.0 kg/m2 and < 40 kg/m2) aged between 18 and 40 years without any other health condition that could interfere with COC eligibility criteria, of whom 45 had PCOS and 45 were age‐matched controls. BMI, waist and hip circumference, arterial blood pressure, fasting insulin and glucose, quantitative insulin sensitivity check index (QUICKI), high‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol, total cholesterol, triglycerides, testosterone, sex hormone‐binding globulin, free androgen index (FAI), carotid stiffness index, intima media thickness, flow‐mediated dilatation (FMD) of the brachial artery and non‐alcoholic fatty liver disease (NAFLD) were assessed.

Results

In women with PCOS, we observed a higher frequency of NAFLD (73.3 vs. 46.7%, P < 0.01) and higher FAI (10.4 vs. 6.8%, P < 0.01). We also observed a trend towards increased insulin levels (10.06 ± 6.66 vs. 7.45 ± 5.88 µIU/mL, P = 0.05), decreased QUICKI (0.36 ± 0.06 vs. 0.39 ± 0.07, P = 0.05) and decreased FMD (7.00 ± 3.87 vs. 8.41 ± 3.79%, P = 0.08). No other significant difference was observed.

Conclusions

NAFLD is frequent in obese women without any other health condition that could interfere with COC eligibility criteria, especially in those with PCOS. This should be considered when choosing the best contraceptive option. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
The aqueduct of Sylvius: a sonographic landmark for neural tube defects in the first trimester
Authors: Finn M. , Sutton D. , Atkinson S. , Ransome K. , Sujenthiran P. , Ditcham V. , Wakefield P. , Meagher S.
Published: September 2011

Objectives

To describe a new first‐trimester sonographic landmark, posterior displacement of the midbrain and aqueduct of Sylvius, which may be useful in early screening for neural tube defects.

Methods

This was a prospective study of 457 normal fetuses at 11 + 0 to 13 + 6 weeks' gestation. We measured the distance from the posterior border of the aqueduct of Sylvius to the anterior border of the occiput (AOS‐to‐occiput distance) in the axial plane and created a reference range. In the nine fetuses with abnormal midbrain position identified in the first trimester and with neural tube defect subsequently confirmed, we analyzed ultrasound images to determine the position of the aqueduct of Sylvius.

Results

The lower limit of normal AOS‐to‐occiput distance (mean minus 2 SD) ranged from 1.7 mm at a crown–rump length (CRL) of 45 mm to 3.7 mm at a CRL of 84 mm. In the nine cases with abnormal position of the midbrain and confirmed neural tube defect, juxtaposition of the midbrain to the occiput was the clue to diagnosis of the spinal abnormality. In all nine cases, the AOS‐to‐occiput distance was below the established normal range.

Conclusions

Examination of the midbrain in an axial plane may prove a reliable marker for the first‐trimester diagnosis of neural tube defects. In contrast to recently reported subtle changes in the mid‐sagittal view of the posterior cranial fossa, axial imaging of the midbrain reveals striking displacement of this structure, with virtual juxtaposition to the occiput, in fetuses with confirmed open spina bifida. This anatomical distortion of the midbrain can be quantified by measurement of the AOS‐to‐occiput distance. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Simulating climate change and its effects on the wind energy resource of Ireland
Authors: Nolan Paul , Lynch Peter , McGrath Ray , Semmler Tido , Wang Shiyu
Published: September 2011

We consider the impact of climate change on the wind energy resource of Ireland using an ensemble of Regional Climate Model (RCM) simulations. The RCM dynamically downscales the coarse information provided by the Global Climate Models (GCMs) and provides high resolution information, on a subdomain covering Ireland. The RCM used in this work is the Rossby Center's RCM (RCA3).

The RCA3 model is evaluated by performing simulations of the past Irish climate, driven by European Center for Medium‐Range Weather Forecasts ERA‐40 data, and by comparing the output to observations. Results confirm that the output of the RCA3 model exhibits reasonable and realistic features as documented in the historical wind data record. For the investigation of the influence of the future climate under different climate scenarios, the Max Plank Institute's GCM, European Center Hamburg Model, is used to drive the RCA3 model. Simulations are run for a control period 1961‐2000 and future period 2021‐2060. The future climate was simulated using the four Intergovernmental Panel on Climate Change emission scenarios A1B, A2, B1 and B2. The results for the downscaled simulations show a substantial overall increase in the energy content of the wind for the future winter months and a decrease during the summer months. The projected changes for summer and winter were found to be statistically significant over most of Ireland. However, the projected changes should be viewed with caution since the climate change signal is of similar magnitude to the variability of the evaluation and control simulations. Copyright © 2011 John Wiley & Sons, Ltd.
Models for networks: a cross‐disciplinary science
Authors: Vivar Juan C. , Banks David
Published: September 2011

This article is an incomplete review of the rapidly growing research on network models. It focuses chiefly upon contributions to network science that have been made by sociologists, physicists, and statisticians. It addresses several topics in the area of dynamic network modeling, which is perhaps the most challenging area of current active research. Several issues in dynamic network modeling are discussed in the context of two applications: baboon grooming networks and growth in the Wikipedia. WIREs Comp Stat 2012, 4:13–27. doi: 10.1002/wics.184

This article is categorized under:

Data: Types and Structure > Graph and Network Data

Data: Types and Structure > Social Networks
From mental health professional to expert witness: Testifying in court
Authors: Bank Steven C.
Published: September 2011

With sweeping changes in health care delivery shrinking an already competitive therapist market, mental health professionals are increasing their participation in the forensic arena. The thread common to civil and criminal psycholegal work is the challenge of testifying as an expert witness.
Zero tolerance: Unfair, with little recourse
Authors: Browne Judith A. , Losen Daniel J. , Wald Johanna
Published: September 2011

This chapter examines racial disparities in the application of zero tolerance, describes legal avenues available to parents and children's advocates, and summarizes recent court decisions issued on school discipline cases.
Alternative strategies for school violence prevention
Authors: Gagnon Joseph C. , Leone Peter E.
Published: September 2011

A number of programs with empirical evidence of effectiveness in addressing problems of aggression and disruption have emerged in schools.
Reaktionen des Alumopolysiloxans (Ph2SiO)8[AlO(OH)]4 mit 4,4′‐Bipyridin und Azobipyridinen
Authors: Veith Michael , Kolano David , Huch Volker , Sutter Jean Pascal
Published: September 2011

The molecular alumosiloxane (Ph2SiO)8(AlO(OH))4·4Et2O (1) reacts with 4,4′‐bipyridine and azobipyridines (4,4′‐azobipyridine and 3,3′‐azobipyridine) to form polymer adducts. The acidic hydroxygroups of 1 interfere with the pyridine‐nitrogen atoms to form O···H···N hydrogen bridges which are the source of one‐ and two‐dimensional networks. As reaction products we have characterized (Ph2SiO)8[AlO(OH)]4·2p‐(C5H4N)2 (2), (Ph2SiO)8[AlO(OH)]4·1.5p‐(C5H4N)2N2·C4H8O (3) and (Ph2SiO)8[AlO(OH)]4·2m‐(C5H4N)2N2 (4). In the crystal structure of 2, the supramolecular adduct forms a one‐dimensional connection. In 3 and 4 two‐dimensional connections are formed. The azobipyridine ligands in solution show cis‐trans‐isomerisation by application of light even in the supramolecular state (as base adducts of (Ph2SiO)8[AlO(OH)]4).
Contraceptive Method Choice Among Youth in the United States: The Importance of Relationship Context
Authors: Kusunoki Yasamin , Upchurch Dawn M.
Published: September 2011

We examine the relationship characteristics associated with contraceptive method choice within young people’s nonmarital sexual relationships, using data from retrospective relationship histories available in the third wave (2001–2002) of the National Longitudinal Study of Adolescent Health. Data-reduction techniques produce a detailed multidimensional characterization of relationship commitment for nonmarital sexual relationships. We then use multilevel analysis to estimate associations between two key relationship characteristics—relationship commitment and couple heterogamy—and the type of contraceptive method used at last sexual intercourse within each relationship. Results indicate that for a given individual, contraceptive method choice varies across relationships as a function of these characteristics, even after we account for important individual and family characteristics and prior relationship experiences.
Impact of histology on prognosis of patients with early‐stage cervical cancer treated with radical surgery
Authors: Rudtanasudjatum Korapin , Charoenkwan Kittipat , Khunamornpong Surapan , Siriaunkgul Sumalee
Published: September 2011

Objective

To examine the effect of carcinoma cell type on tumor characteristics, tumor spread, tumor recurrence, and survival of patients with early‐stage cervical cancer who had radical hysterectomy and pelvic lymphadenectomy.

Method

Data from 499 patients with stage IA to IIA cervical carcinoma who received primary surgical treatment from 2003 to 2005 at Chiang Mai University were retrospectively reviewed with regard to 3 histologic types; squamous cell carcinoma (SCC), adenocarcinoma (AC), and adenosquamous carcinoma (AS).

Results

Among the 499 patients, 71.1% had SCC, 23.4% had AC, and 5.4% had AS. There was no significant difference in stage, tumor size, tumor characteristics, or rate of loco‐regional spread. A higher proportion of women with SCC needed adjuvant radiation (P = 0.001). Five‐year recurrence‐free survival (RFS) and overall survival (OS) were comparable among the groups. Among patients with pelvic node metastasis, 5‐year RFS and OS were significantly lower in those with AC than in those with SCC (RFS, 66.1% versus 86.4%, P = 0.02; OS, 68.2% versus 88.2%, P = 0.05).

Conclusion

There was no difference among SCC, AC, and AS in most tumor characteristics, spread, recurrence, and survival in patients with early‐stage cervical cancer. Among patients with pelvic lymph node metastasis, AC was associated with less favorable outcomes than SCC.
High-frequency observations of pH under Antarctic sea ice in the southern Ross Sea
Authors: Matson Paul G. , Martz Todd R. , Hofmann Gretchen E.
Published: September 2011

Although predictions suggest that ocean acidification will significantly impact polar oceans within 20–30 years, there is limited information regarding present-day pH dynamics of the Southern Ocean. Here, we present novel high-frequency observations of pH collected during spring of 2010 using SeaFET pH sensors at three locations under fast sea ice in the southern Ross Sea. During these deployments in McMurdo Sound, baseline pH ranged between 8.019–8.045, with low to moderate overall variation (0.043–0.114 units) on the scale of hours to days. The variation was predominantly in the direction of increased pH relative to baseline observations. Estimates of aragonite saturation state (ΩAr) were > 1 with no observations of subsaturation. Time series records such as these are significant to the Antarctic science community; this information can be leveraged towards framing more environmentally relevant laboratory experiments aimed at assessing the vulnerability of Antarctic species to ocean acidification. In addition, increased spatial and temporal coverage of pH datasets may reveal ecologically significant patterns. Specifically, whether such variation in natural ocean pH dynamics may drive local adaptation to pH variation or provide refugia for populations of marine calcifiers in a future, acidifying ocean.
Fixed ground stations for multi-satellite geostationary missions
Authors: Pasian Marco , Cametti Marta , Bozzi Maurizio , Perregrini Luca , Rawson Steve
Published: September 2011

Multi-satellite missions, such as the next generation of METEOSAT geostationary satellites, require a ground station able to support an arbitrary number of satellites that can fly wherever within a pre-determined sky region, called control box. The use of high frequencies, around 26 GHz, imposes on the ground station high antenna gains to compensate for the noise temperature collected at those frequencies to obtain the specified G/T. Regardless of the narrow beamwidths that emerged from the adoption of high antenna gains, it is also required to operate with fixed (i.e. without any kind of tracking) antennas. This paper shows how all these specifications drive a new type of ground station with respect to current solutions. The proposed architecture is based on a multi-reflector system able to provide a set of interleaved beams, which generates an almost uniform coverage of the control box. The architecture is analyzed and designed, optimizing all the main antenna parameters, and presenting the analytical results.
W-band beam-steerable MEMS-based reflectarray
Authors: Montori Simone , Chiuppesi Elisa , Farinelli Paola , Marcaccioli Luca , Gatti Roberto Vincenti , Sorrentino Roberto
Published: September 2011

This paper presents recent advances on reconfigurable reflectarrays at the University of Perugia. In particular, the activities carried out in the framework of the FP7 project ARASCOM (“MEMS and Liquid Crystal based” Agile Reflectarray Antennas for Security and COMmunication). As for ARASCOM outcomes, the purpose of the project is the design of a very large reconfigurable reflectarray controlled with micro-electro-mechanical systems (MEMS) for mm-wave imaging system at 76.5 GHz. A system with sufficient resolution to detect concealed weapons impose challenging requirements on the antenna, which shall be made of hundreds of thousands elements. The problem has been addressed by exploiting some innovative solutions and architectures that will be described in this document. In particular, the dimensioning of the reflectarray, the proposed 1-bit geometry of elementary cell, and the innovative biasing control architecture are reported together with the MEMS design and fabrication and the experimental results of a demonstrating board that validated the adopted procedure.
Sustainable syntrophic growth of Dehalococcoides ethenogenes strain 195 with Desulfovibrio vulgaris Hildenborough and Methanobacterium congolense: global transcriptomic and proteomic analyses
Authors: Men Yujie , Feil Helene , VerBerkmoes Nathan C , Shah Manesh B , Johnson David R , Lee Patrick K H , West Kimberlee A , Zinder Stephen H , Andersen Gary L , Alvarez-Cohen Lisa
Published: September 2011

Dehalococcoides ethenogenes strain 195 (DE195) was grown in a sustainable syntrophic association with Desulfovibrio vulgaris Hildenborough (DVH) as a co-culture, as well as with DVH and the hydrogenotrophic methanogen Methanobacterium congolense (MC) as a tri-culture using lactate as the sole energy and carbon source. In the co- and tri-cultures, maximum dechlorination rates of DE195 were enhanced by approximately three times (11.0±0.01 μmol per day for the co-culture and 10.1±0.3 μmol per day for the tri-culture) compared with DE195 grown alone (3.8±0.1 μmol per day). Cell yield of DE195 was enhanced in the co-culture (9.0±0.5 × 107 cells per μmol Cl− released, compared with 6.8±0.9 × 107 cells per μmol Cl− released for the pure culture), whereas no further enhancement was observed in the tri-culture (7.3±1.8 × 107 cells per μmol Cl− released). The transcriptome of DE195 grown in the co-culture was analyzed using a whole-genome microarray targeting DE195, which detected 102 significantly up- or down-regulated genes compared with DE195 grown in isolation, whereas no significant transcriptomic difference was observed between co- and tri-cultures. Proteomic analysis showed that 120 proteins were differentially expressed in the co-culture compared with DE195 grown in isolation. Physiological, transcriptomic and proteomic results indicate that the robust growth of DE195 in co- and tri-cultures is because of the advantages associated with the capabilities of DVH to ferment lactate to provide H2 and acetate for growth, along with potential benefits from proton translocation, cobalamin-salvaging and amino acid biosynthesis, whereas MC in the tri-culture provided no significant additional benefits beyond those of DVH.
Black reefs: iron-induced phase shifts on coral reefs
Authors: Kelly Linda Wegley , Barott Katie L , Dinsdale Elizabeth , Friedlander Alan M , Nosrat Bahador , Obura David , Sala Enric , Sandin Stuart A , Smith Jennifer E , Vermeij Mark J A , Williams Gareth J , Willner Dana , Rohwer Forest
Published: September 2011

The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the shipwreck debris are characterized by high benthic cover of turf algae, macroalgae, cyanobacterial mats and corallimorphs, as well as particulate-laden, cloudy water. These sites also have very low coral and crustose coralline algal cover and are call black reefs because of the dark-colored benthic community and reduced clarity of the overlying water column. Here we use a combination of benthic surveys, chemistry, metagenomics and microcosms to investigate if and how shipwrecks initiate and maintain black reefs. Comparative surveys show that the live coral cover was reduced from 40 to 60% to <10% on black reefs on Millennium, Tabuaeran and Kingman. These three sites are relatively large (>0.75 km2). The phase shift occurs rapidly; the Kingman black reef formed within 3 years of the ship grounding. Iron concentrations in algae tissue from the Millennium black reef site were six times higher than in algae collected from reference sites. Metagenomic sequencing of the Millennium Atoll black reef-associated microbial community was enriched in iron-associated virulence genes and known pathogens. Microcosm experiments showed that corals were killed by black reef rubble through microbial activity. Together these results demonstrate that shipwrecks and their associated iron pose significant threats to coral reefs in iron-limited regions.
Atomic and electronic structures of the SrVO3-LaAlO3 interface
Authors: Chi Miaofang , Mizoguchi Teruyasu , Martin Lane W. , Bradley John P. , Ikeno Hidekazu , Ramesh Ramamoorthy , Tanaka Isao , Browning Nigel
Published: September 2011

The atomic and electronic structures at interfaces in thin films are typically different from the bulk and are vitally important in determining the physical properties of thin films. The interface between SrVO3, chosen as a prototype for vanadium-based perovskite materials in this work, and LaAlO3 substrate is investigated by scanning transmission electron microscopy, electron energy-loss spectroscopy, and theoretical multi-electron calculations. Extra electrons have been detected on the interface layer by comparing the energy-loss near-edge structures of V-L3,2 edges to those from the film far from the interface. Monochromated EELS and theoretical calculations for SrVO3, VO2, and V2O3 support this conclusion. The extra electrons appear to originate from a change in the local bonding configuration of V at the La-O terminated substrate surface as determined by Z-contrast imaging.
Bulk modulus of Sc2O3: Ab initio calculations and experimental results
Authors: Barzilai S. , Halevy I. , Yeheskel O.
Published: September 2011

The bulk modulus of scandia is evaluated by ab initio calculation, based on density functional theory, and compared with bulk modulus measurement on nearly fully dense scandia and with the value attained from the equation of state based on diamond anvil cell measurements. The current results are in the upper range of the bulk moduli results in the literature. The scatter in the literature results might be explained by the differences in the specific volumes of the measured and calculated cases. For the specific volume of 59.65 ± 0.07 Å3 the average measured isothermal bulk modulus of scandia from the present study and recent literature results is 188 ± 10 GPa.
Response to “Comment on ‘Heating of ions by low-frequency Alfvén waves in partially ionized plasmas’” [Phys. Plasmas 18, 084703 (2011)]
Authors: Dong Chuanfei , Paty Carol S.
Published: September 2011

The calculation of temperature in a plasma system that is not in thermal equilibrium remains a topic of debate. In our article [Dong and Paty, Phys. Plasmas 18, 030702 (2011)] we use the average kinetic energy to calculate the “kinetic temperature” in a non-equilibrium system to quantify the heating of ions by low-frequency Alfvén waves in a partially ionized plasma (i.e., where collisions with neutrals can not be ignored). We implement a method previously used by Wang, Wu and Yoon [Wang, Wu and Yoon, Phys. Rev. Lett. 96, 125001 (2006)] and several others studying the effects of low frequency Alfvén waves in collisionless plasmas. This method is appropriate for several reasons discussed in this response. Most notably, we implement it to investigate heating of the plasma population since the bulk velocity of the particle ensemble perpendicular to the ambient magnetic field remains zero during the numerical experiment.
Black thin film silicon
Authors: Koynov Svetoslav , Brandt Martin S. , Stutzmann Martin
Published: September 2011

“Black etching” has been proposed previously as a method for the nanoscale texturing of silicon surfaces, which results in an almost complete suppression of reflectivity in the spectral range of absorption relevant for photovoltaics. The method modifies the topmost 150 to 300 nm of the material and thus also is applicable for thin films of silicon. The present work is focused on the optical effects induced by the black-etching treatment on hydrogenated amorphous and microcrystalline silicon thin films, in particular with respect to their application in solar cells. In addition to a strong reduction of the reflectivity, efficient light trapping within the modified thin films is found. The enhancement of the optical absorption due to the light trapping is investigated via photometric measurements and photothermal deflection spectroscopy. The correlation of the texture morphology (characterized via atomic force microscopy) with the optical effects is discussed in terms of an effective medium with gradually varying optical density and in the framework of the theory of statistical light trapping. Photoconductivity spectra directly show that the light trapping causes a significant prolongation of the light path within the black silicon films by up to 15 μm for ∼1 μm thick films, leading to a significant increase of the absorption in the red.
Impact of nonpolar AlGaN quantum wells on deep ultraviolet laser diodes
Authors: Kojima K. , Yamaguchi A. A. , Funato M. , Kawakami Y. , Noda S.
Published: September 2011

The radiation properties of nonpolar AlGaN quantum wells (QWs) were theoretically investigated by comparing them to those of c-plane AlGaN QWs with heavy holes as the top valence band (VB). First, the conditions to minimize the threshold carrier density of c-plane QW laser diodes were explored. A thin well width (∼1 nm) and reduction of the Al content in the well layer were important to reduce threshold carrier density because narrow wells suppressed the quantum confined Stark effect and AlGaN with a lower Al content had a lower density of states. Moreover, the emission wavelength was widely controlled by tuning the Al contents of both the well and barrier layers under the proposed conditions. Then the properties of nonpolar AlGaN QWs were investigated. Nonpolar AlGaN had several superior characteristics compared to c-plane QWs, including large overlap integrals, optical polarization suitable for both edge and surface emissions, an almost linearly polarized optical dipole between the conduction band and top VB due to the isolated VBs, and a reduced VB density of state. Finally, the threshold carrier densities of both nonpolar and optimized c-plane QWs were compared as functions of the transition wavelength. At a given wavelength, the threshold of nonpolar QWs was lower than that of c-plane ones. Particularly below 260 nm, nonpolar QWs had a low threshold, whereas that of c-plane QWs drastically increased due to the large VB mass of AlN and carrier population in the crystal-field splitting band.