bluuebunny/crossref_metadata_2025 huggingface dataset:
Air pollution and carotid arterial stiffness in children
Authors: Iannuzzi Arcangelo , Verga Maria Carmela , Renis Maurizio , Schiavo Alfonso , Salvatore Vittorio , Santoriello Carlo , Pazzano Dario , Licenziati Maria Rosaria , Polverino Mario
Published: March 2010

Background and purpose

Many studies unequivocally indicate that air pollution is directly linked to the adverse cardiovascular outcomes in the general population. No data are currently available on cardiovascular effects of exposure to trafficked roads in healthy children. Distance of the residence to a major road has been shown to be a useful proxy for long-term traffic exposure and seem to be more consistently associated with atherosclerosis than particulate matter2.5. The aim of this study was to investigate a possible association between the distance to a major road and carotid arterial subclinical markers of atherosclerosis in a group of children in Italy.

Methods

The participants consisted of 52 healthy children living in a small town of the Amalphitan Coast with only one highly trafficked road. All children underwent an ultrasound carotid arterial examination.

Results

A statistically significant difference was found in carotid arterial stiffness between children living closer to the main street and other children, both those living between 330 and 730 metres from the main street and those living more than 750 metres from the main street. No significant differences were detectable in carotid arterial thickness and arterial blood pressure among the three groups of children.

Conclusion

This study provides evidence in support of an association of exposure to air pollution with early atherosclerotic markers in healthy children. Impaired vascular health in childhood and adolescence gives further substance to the hypothesis that traffic exhausts are relevant to cardiovascular diseases even early in life.
The Real CIG – Who are They?
Authors: Coburn Andrew
Published: March 2010

Andrew Coburn the 2009 Chairman of the CILIP Cataloguing and Indexing Group describes its activities, including continuing professional development, in the form of meetings and courses; work on standards and the opportunities it provides for networking.
Business Continuity Planning: Reciprocal Agreements for Law Libraries
Authors: Mason Dean
Published: March 2010

In the first in our series of very short articles devoted to practical library and information management issues, Dean Mason from Salans provides helpful advice on how to set up a business continuity plan for your information service.
Search Engine Optimisation and Automatic Classification
Authors: Sturdy Derek
Published: March 2010

Derek Sturdy explains the importance of search engine optimisation for the legal information professional involved in the organisation's website in the Google era and suggests that the most important pieces of information are the title and the abstract. He also discusses the rise in automatic classification in the enterprise search context.
Cataloguing: AACR2 and All That
Authors: Holborn Guy
Published: March 2010

Guy Holborn, Librarian of Gray's Inn, gives some very practical help on how to catalogue the law collection whilst ensuring compliance with cataloguing standards
Getting the Right Balance: Information Security and Information Access
Authors: Smith Jennifer
Published: March 2010

This article by former law librarian, Jennifer Smith, highlights access and security issues to consider when handling sensitive information. Jennifer is a Director of the Information Management and IT consultancy, OneIS, which specialises in working with smaller organisations with complex information management requirements. The article provides practical advice and is particularly aimed at readers working in organisations without dedicated information security professionals.
Neteracy in Nova Scotia – Themes from the 2009 CALL/ACBD Conference
Authors: Furlong John
Published: March 2010

John Furlong attended the Annual Conference of the Canadian Association of Law Librarians (CALL/ACBD) and was particularly interested in the sessions involving the way in which clients are now taught about legal materials and the importance of teaching internet literacy or “neteracy”.
Information Matters: Government's Strategy to Build Capability in Managing Its Knowledge and Information Assets
Authors: Woolf Katie
Published: March 2010

This article by Katie Woolf, formerly of the Government Knowledge and Information Network, looks at the new UK Government strategy for knowledge and information (KIM). Led by the Knowledge Council, the strategy sets out the principles and actions government must take to develop the capability it needs to manage corporate knowledge and information as the key business assets they are. It discusses how the strategy will be achieved through a departmental delivery model, the relationship of the strategy with the Information Assurance agenda post data loss scandals, and the need for senior leader engagement to be the driving force to building a culture that values KIM.
Indexing of Free, Web-based Electronic Resources
Authors: Browne Glenda
Published: March 2010

The internet provides access to a huge amount of information, and most people experience problems with information overload rather than scarcity. Glenda Browne explains how indexing provides a way of increasing retrieval of relevant information from the content available. Manual, book-style indexes can be created for websites and individual web documents such as online books. Keyword metadata is a crucial behind the scenes aid to improved search engine functioning, and categorisation, social bookmarking and automated indexing also play a part.
AlGaN/GaN epitaxy and technology
Authors: Waltereit Patrick , Bronner Wolfgang , Quay Rüdiger , Dammann Michael , Kiefer Rudolf , Pletschen Wilfried , Müller Stefan , Aidam Rolf , Menner Hanspeter , Kirste Lutz , Köhler Klaus , Mikulla Michael , Ambacher Oliver
Published: March 2010

We present an overview on epitaxial growth, processing technology, device performance, and reliability of our GaN high electron mobility transistors (HEMTs) manufactured on 3- and 4-in. SiC substrates. Epitaxy and processing are optimized for both performance and reliability. We use three different gate lengths, namely 500 nm for 1–6 GHz applications, 250 nm for devices between 6 and 18 GHz, and 150 nm for higher frequencies. The developed HEMTs demonstrate excellent high-voltage stability, high power performance, and large DC to RF conversion efficiencies for all gate lengths. On large gate width devices for base station applications, an output power beyond 125 W is achieved with a power added efficiency around 60% and a linear gain around 16 dB. Reliability is tested both under DC and RF conditions with supply voltage of 50 and 30 V for 500 and 250 nm gates, respectively. DC tests on HEMT devices return a drain current change of just about 10% under IDQ conditions. Under RF stress the observed change in output power density is below 0.2 dB after more than 1000 h for both gate length technologies.
Industrial GaN FET technology
Authors: Blanck Hervé , Thorpe James R. , Behtash Reza , Splettstößer Jörg , Brückner Peter , Heckmann Sylvain , Jung Helmut , Riepe Klaus , Bourgeois Franck , Hosch Michael , Köhn Dominik , Stieglauer Hermann , Floriot Didier , Lambert Benoît , Favede Laurent , Ouarch Zineb , Camiade Marc
Published: March 2010

GaN technology has gained a lot of attention in Europe over the last few years for various domains including RF electronics. After a few years of active observation, United Monolithic Semiconductors (UMS) has taken the decision to introduce a GaN technology family in its portfolio. Based on its extensive experience of III–V technology and the intensive support and collaboration with partners and European research institutes, UMS has developed the capability to produce state-of-the-art GaN devices and circuits. The present paper will summarize the current status achieved and illustrate it with a few representative examples. Aspects covering material, devices, and circuits will be addressed.
Evaluation of GaN technology in Doherty power amplifier architectures
Authors: Colantonio Paolo , Giannini Franco , Giofrè Rocco , Piazzon Luca
Published: March 2010

The aim of the present paper is to highlight the possible benefits coming from the use of the GaN high electron-mobility transistor (HEMT) technology in the Doherty power amplifier (DPA) architecture. In particular, the attention is focused on the capabilities and the relevant drawbacks of a GaN HEMT technology when designing DPAs. A deep discussion of the DPA's design guidelines is also presented through the realization of three prototypes implementing different design solutions and working at 2.14 GHz. The first example is a tuned load DPA (TL-DPA), which show an average drain efficiency of 40.7% with 3 W of saturated output power in the obtained 6 dB of output back-off. The second DPA was designed implementing a class F harmonic termination for the main device, which allows an improvement of roughly 15% in output power and efficiency behavior with respect to the TL-DPA. The last DPA was realized implementing a single output matching network for both main and auxiliary devices, which allows a relevant reduction in the size of the resulting DPA, without downgrading the overall performances.
A hidden Markov model for earthquake declustering
Authors: Wu Zhengxiao
Published: March 2010

The hidden Markov model (HMM) and related algorithms provide a powerful framework for statistical inference on partially observed stochastic processes. HMMs have been successfully implemented in many disciplines, though not as widely applied as they should be in earthquake modeling. In this article, a simple HMM earthquake occurrence model is proposed. Its performance in declustering is compared with the epidemic‐type aftershock sequence model, using a data set of the central and western regions of Japan. The earthquake clusters and the single earthquakes separated using our model show some interesting geophysical differences. In particular, the log‐linear Gutenberg‐Richter frequency‐magnitude law (G‐R law) for the earthquake clusters is significantly different from that for the single earthquakes.
Paleointensity estimates from ignimbrites: An evaluation of the Bishop Tuff
Authors: Gee Jeffrey S. , Yu Yongjae , Bowles Julie
Published: March 2010

Ash flow tuffs, or ignimbrites, typically contain fine‐grained magnetite, spanning the superparamagnetic to single‐domain size range that should be suitable for estimating geomagnetic field intensity. However, ignimbrites may have a remanence of thermal and chemical origin as a result of the complex magnetic mineralogy and variations in the thermal and alteration history. We examined three stratigraphic sections through the ∼0.76 Ma Bishop Tuff, where independent information on postemplacement cooling and alteration is available, as a test of the suitability of ignimbrites for paleointensity studies. Thermomagnetic curves suggest that low‐Ti titanomagnetite (Tc = 560°C–580°C) is the dominant phase, with a minor contribution from a higher Tc phase(s). Significant remanence unblocking above 580°C suggests that maghemite and/or (titano)maghemite is an important contributor to the remanence in most samples. We obtained successful paleofield estimates from remanence unblocked between 440°C and 580°C for 46 of 89 specimens (15 sites at two of three total localities). These specimens represent a range of degrees of welding and have variable alteration histories and yet provide a consistent paleofield estimate of 43.0 μT (±3.2), equivalent to a VADM of 7.8 × 1022 Am2. The most densely welded sections of the tuff have emplacement temperatures inferred to be as high as ∼660°C, suggesting that the remanence may be primarily thermal in origin, though a contribution from thermochemical remanence cannot be excluded. These results suggest that ignimbrites may constitute a viable material for reliable paleointensity determinations.
Feedbacks on convection from an African wetland
Authors: Taylor Christopher M.
Published: March 2010

The Niger Inland Delta in Mali floods every year in response to rain falling hundreds of kilometers upstream. This study examines the remote hydrological feedback between rainfall, fluvial inundation, and new convective storms. A satellite thermal infra‐red dataset spanning 24 years is used to quantify both temporal variability in wetland extent, and the response of cloud cover to the wetland during August and September. The daytime initiation of convective storms is found to double during periods of inundation, consistent with a hypothesised “wetland breeze” effect. A signal of enhanced cloud cover propagates hundreds of kilometers westwards, linked to increased numbers of long‐lived Mesoscale Convective Systems emanating from the wetland region. This effect raises the possibility that changes in upstream water use could have a climatic impact over a wide area.
Radon and thoron emission from lithophysae‐rich tuff under increasing deformation: An experimental study
Authors: Tuccimei P. , Mollo S. , Vinciguerra S. , Castelluccio M. , Soligo M.
Published: March 2010

Radon and thoron emissions from lithophysae‐rich tuff under increasing deformation are measured to determine how mechanical damage affects gas emission levels in tuffs. Mechanical properties of rocks under stresses should be carefully considered to properly interpret data from geochemical field monitoring. Two samples are uniaxially loaded up to failure, while two others are unloaded at the end of the elastic phase, in order to achieve the highest compaction of existing pores. Changes in the porosity of deformed samples are evidenced by helium pycnometer and microscopy analyses. Radon and thoron exhalation rates are measured on groups of two samples by alpha spectrometer technique. Results show that tuff samples are characterised by a dual porosity consisting of a macroporosity, given by isolated large pores with sizes from mm‐ up to cm‐scale and a microporosity ranging between microns to hundreds of microns. At the end of the elastic phase pervasive pore collapse is observed, due to the closure of the cm‐scale macropores. This is mirrored by a significant decrease of radon and thoron release. After failure, a further reduction of porosity in the rock adjacent to the fault planes is observed due to extensive closure of both macropores and micropores. At this stage radon and thoron emissions increase. The formation of new exhaling surfaces is the main carrier of the bulk increase of radon and thoron exhalations, strongly prevailing over the densification carried out from the compaction mechanisms. In terms of volcanic hazard, negative anomalies in radon emissions should be considered as indicators of forthcoming ruptures. Key words: radon and thoron exhalation, tuff deformation, seismic precursor.
Polarity and energetics of inner core lightning in three intense North Atlantic hurricanes
Authors: Thomas Jeremy N. , Solorzano Natalia N. , Cummer Steven A. , Holzworth Robert H.
Published: March 2010

We use the World Wide Lightning Location Network (WWLLN), low‐frequency magnetic fields measured at Duke University, and storm intensity data (winds and central pressure) to examine the polarity and energetics of lightning within 100 km of the centers (inner core regions) of North Atlantic hurricanes Emily, Katrina, and Rita (2005). WWLLN provides the lightning locations. Polarities, peak currents, and vertical impulse charge moment changes are derived from the Duke magnetic field measurements. In agreement with past studies, we find episodic inner core lightning outbreaks prior to and during most changes in storm intensity. A new result of our analysis indicates an increase in the relative number of positive cloud‐to‐ground lightning in the inner core prior to and during periods of storm weakening, which is potentially important for hurricane intensity change forecasting. Additionally, we find that the majority of inner core lightning located by WWLLN had peak currents that surpassed the threshold needed to produce optical emissions (elves) and drive electron density perturbations in the lower ionosphere (80–105 km). Since these high peak current lightning occurred in short‐duration outbreaks, they had an accumulated effect on the ionospheric electron density, as shown by recent modeling studies. Our results suggest that the inner core lightning in intense hurricanes might be significant drivers of perturbations in the lower ionosphere during these inner core lightning outbreaks.
Local determination of ionospheric plasma convection from coherent scatter radar data using the SECS technique
Authors: Amm O. , Grocott A. , Lester M. , Yeoman T. K.
Published: March 2010

A new technique for merging line‐of‐sight (LOS) data of the ionospheric plasma convection velocity, as obtained from coherent scatter radars, into a full velocity vector field on a sphere is presented. This technique is based on the expansion into Spherical Elementary Current Systems (SECS) which have been successfully applied to many other problems in ionosphere‐magnetosphere physics. Despite their name mentioning currents for historical reasons, SECS can be used as basis functions for any continuously differentiable vector field on a sphere. In contrast to the traditional modeling of the radar data with spherical harmonics over the whole auroral zone, the new technique does not require any “a priori” model input but relies solely on the measured data, nor does it need any explicit boundary conditions to be specified. The new technique is designed to be applied locally to areas where sufficient radar backscatter exists. The analysis area that satisfies this condition may have any shape and is not limited to, e.g., spherical caps. A test with synthetic data shows that the method performs excellently (less than 5% relative error) if 25% or more of the optimal coverage of input data are actually available as backscatter data, with respect to the scale on which the results for the velocity vector field are desired to be obtained. Still if only 10% of the optimal coverage of input data are available, the technique performs fairly well with a relative error of ∼12%. A second test with real LOS input data from the SuperDARN radars shows that on such a local area with sufficient backscatter, our new technique is able to reproduce mesoscale details of the LOS data significantly better than the current standard analysis based on the technique of Ruohoniemi and Baker (1998) which processes the radar data on the whole auroral zone. While the new technique is presented here for the application with LOS radar data, it can be applied for merging any kind of vector component data on a sphere to a vector field.
Transport in the hydrologic response: Travel time distributions, soil moisture dynamics, and the old water paradox
Authors: Botter Gianluca , Bertuzzo Enrico , Rinaldo Andrea
Published: March 2010

We propose a mathematical framework for the general definition and computation of travel time distributions defined by the closure of a catchment control volume, where the input flux is an arbitrary rainfall pattern and the output fluxes are green and blue water flows (namely, evapotranspiration and the hydrologic response embedding runoff production through soil water dynamics). The relevance of the problem is both practical, owing to implications in hydrologic watershed modeling, and conceptual for the linkages and the explanations the theory provides, chiefly concerning the role of geomorphology, climate, soils, and vegetation through soil water dynamics and the treatment of the so‐called old water paradox. The work focuses in particular on the origins of the conditional and time‐variant nature of travel time distributions and on the differences between unit hydrographs and travel time distributions. Both carrier flow and solute matter transport in the control volume are accounted for coherently. The key effect of mixing processes occurring within runoff production is also investigated, in particular by a model that assumes that mobilization of soil water involves randomly sampled particles from the available storage. Travel time distributions are analytically expressed in terms of the major water fluxes driving soil moisture dynamics, irrespectively of the specific model used to compute them. Relevant numerical examples and a set of generalized applications are provided and discussed.
New periodicity in Jovian decametric radio emission
Authors: Panchenko M. , Rucker H. O. , Kaiser M. L. , St. Cyr O. C. , Bougeret J.‐L. , Goetz K. , Bale S. D.
Published: March 2010

We report on the finding of a new periodicity in the Jovian decametric radio emission (DAM). Periodic bursts of non‐Io component of DAM which recur with a period 1.5% longer than the Jupiter rotation (System III) have been found in the dynamic radio spectra acquired by STEREO/WAVES, Wind/WAVES and Cassini/RPWS during the years 2002–2008. Typically, the bursts appear very periodically over several Jovian days with a decreasing intensity and they display a negative frequency drift. All the bursts were detected within the same sector of Jovian Central Meridian Longitude (III), between 300° and 60° (via 360°) of CML (III), close to the region of the non‐Io‐C source. No correlation has been found with the position of Io. Considering the simultaneous stereoscopic observations onboard STEREO‐A and STEREO‐B, as well as Wind and Cassini we can conclude that the sources of the periodic bursts most probably sub‐corotate with Jupiter.
Nitrogen and phosphorus enrichment alter the composition of ammonia-oxidizing bacteria in salt marsh sediments
Authors: Lage Melissa D , Reed Heather E , Weihe Claudia , Crain Caitlin M , Martiny Jennifer B H
Published: March 2010

Ammonia oxidation is a central process in the nitrogen cycle. Particularly in marine and estuarine environments, few experiments have been conducted to tease apart the factors influencing their abundance and composition. To investigate the effect of nitrogen and phosphorus availability on ammonia-oxidizing bacteria (AOB), we conducted a nutrient enrichment experiment in a Maine salt marsh and sampled sediment communities in three seasons over 2 years. We assessed community composition using terminal restriction fragment length polymorphism analysis and sequencing of cloned fragments of the ammonia monooxygenase (amoA) gene. Almost all of the amoA sequences fell within the marine and estuarine-specific Nitrosospira-like clade. Applied separately, nitrogen and phosphorus significantly altered AOB composition; however, together the nutrients had an interactive effect, and composition did not change. In contrast, nutrient enrichment did not alter AOB abundance. Furthermore, the response of AOB composition to nutrient enrichment varied over time. We conclude that closely related taxa within the marine/estuarine-specific Nitrosospira-like clade vary in their preference for nutrient concentrations, and this preference may depend on other temporally variable abiotic factors. Finally, AOB composition was highly variable within and across years even in untreated plots. Further studies are needed to test how these different aspects of compositional variability in AOB communities influence nitrogen cycling.
Silica deposition and phenotypic changes to Thermus thermophilus cultivated in the presence of supersaturated silicia
Authors: Iwai Satoru , Doi Katsumi , Fujino Yasuhiro , Nakazono Takeo , Fukuda Kosai , Motomura Yoshinobu , Ogata Seiya
Published: March 2010

Thermus thermophilus cells formed siliceous deposits in the presence of supersaturated silicic acid (600 p.p.m SiO2). The supersaturated silicic acid promoted interaction between cells and the inside walls of glass culture bottles, leading to the development of cell aggregates or biofilms. Electron probe microanalysis showed that within the aggregates most of the cell surfaces were covered with silica. Under these conditions, there was remarkable production of silica-induced protein (Sip), a solute-binding component of the Fe3+-binding ABC transporter. Furthermore, supersaturated silica enhanced resistance to the peptide antibiotics bacitracin, colistin and polymyxin B, which all act on the cell envelope. By contrast, supersaturated silica did not induce resistance to ampicillin, chloramphenicol, kanamycin and tetracycline, which inhibit peptide synthesis. Although strong expression of Sip was detected in liquid cultures of T. thermophilus in the presence of supersaturated silica and colistin, upregulated transcription of putative efflux pump and multidrug resistance ABC transporter genes were not detected by quantitative real-time PCR analysis. These findings suggest Sip promotes silica deposition on the surfaces of cells, after which the silicified outer membrane may serve as a ‘suit-of-armor,’ conferring resistance to peptide antibiotics.
Development and quantitative analyses of a universal rRNA-subtraction protocol for microbial metatranscriptomics
Authors: Stewart Frank J , Ottesen Elizabeth A , DeLong Edward F
Published: March 2010

Metatranscriptomes generated by pyrosequencing hold significant potential for describing functional processes in complex microbial communities. Meeting this potential requires protocols that maximize mRNA recovery by reducing the relative abundance of ribosomal RNA, as well as systematic comparisons to identify methodological artifacts and test for reproducibility across data sets. Here, we implement a protocol for subtractive hybridization of bacterial rRNA (16S and 23S) that uses sample-specific probes and is applicable across diverse environmental samples. To test this method, rRNA-subtracted and unsubtracted transcriptomes were sequenced (454 FLX technology) from bacterioplankton communities at two depths in the oligotrophic open ocean, yielding 10 data sets representing ∼350 Mbp. Subtractive hybridization reduced bacterial rRNA transcript abundance by 40–58%, increasing recovery of non-rRNA sequences up to fourfold (from 12% to 20% of total sequences to 40–49%). In testing this method, we established criteria for detecting sequences replicated artificially via pyrosequencing errors and identified such replicates as a significant component (6–39%) of total pyrosequencing reads. Following replicate removal, statistical comparisons of reference genes (identified via BLASTX to NCBI-nr) between technical replicates and between rRNA-subtracted and unsubtracted samples showed low levels of differential transcript abundance (<0.2% of reference genes). However, gene overlap between data sets was remarkably low, with no two data sets (including duplicate runs from the same pyrosequencing library template) sharing greater than 17% of unique reference genes. These results indicate that pyrosequencing captures a small subset of total mRNA diversity and underscores the importance of reliable rRNA subtraction procedures to enhance sequencing coverage across the functional transcript pool.
Novel observations of Thiobacterium, a sulfur-storing Gammaproteobacterium producing gelatinous mats
Authors: Grünke Stefanie , Lichtschlag Anna , Beer Dirk , Kuypers Marcel , Lösekann-Behrens Tina , Ramette Alban , Boetius Antje
Published: March 2010

The genus Thiobacterium includes uncultivated rod-shaped microbes containing several spherical grains of elemental sulfur and forming conspicuous gelatinous mats. Owing to the fragility of mats and cells, their 16S ribosomal RNA genes have not been phylogenetically classified. This study examined the occurrence of Thiobacterium mats in three different sulfidic marine habitats: a submerged whale bone, deep-water seafloor and a submarine cave. All three mats contained massive amounts of Thiobacterium cells and were highly enriched in sulfur. Microsensor measurements and other biogeochemistry data suggest chemoautotrophic growth of Thiobacterium. Sulfide and oxygen microprofiles confirmed the dependence of Thiobacterium on hydrogen sulfide as energy source. Fluorescence in situ hybridization indicated that Thiobacterium spp. belong to the Gammaproteobacteria, a class that harbors many mat-forming sulfide-oxidizing bacteria. Further phylogenetic characterization of the mats led to the discovery of an unexpected microbial diversity associated with Thiobacterium.
Association of Pericardial Fat With Liver Fat and Insulin Sensitivity After Diet‐Induced Weight Loss in Overweight Women
Authors: Bosy‐Westphal Anja , Kossel Elke , Goele Kristin , Blöcker Thordis , Lagerpusch Merit , Later Wiebke , Heller Martin , Glüer Claus C. , Müller Manfred J.
Published: March 2010

Pericardial adipose tissue (PAT) is positively associated with fatty liver and obesity‐related insulin resistance. Because PAT is a well‐known marker of visceral adiposity, we investigated the impact of weight loss on PAT and its relationship with liver fat and insulin sensitivity independently of body fat distribution. Thirty overweight nondiabetic women (BMI 28.2–46.8 kg/m2, 22–41 years) followed a 14.2 ± 4‐weeks low‐calorie diet. PAT, abdominal subcutaneous (SAT), and visceral fat volumes (VAT) were measured by magnetic resonance imaging (MRI), total fat mass, trunk, and leg fat by dual‐energy X‐ray absorptiometry and intrahepatocellular lipids (IHCL) by (1)H‐magnetic resonance spectroscopy. Euglycemic hyperinsulinemic clamp (M) and homeostasis model assessment of insulin resistance (HOMAIR) were used to assess insulin sensitivity or insulin resistance. At baseline, PAT correlated with VAT (r = 0.82; P < 0.001), IHCL (r = 0.46), HOMAIR (r = 0.46), and M value (r = −0.40; all P < 0.05). During intervention, body weight decreased by −8.5%, accompanied by decreases of −12% PAT, −13% VAT, −44% IHCL, −10% HOMA2‐%B, and +24% as well as +15% increases in HOMA2‐%S and M, respectively. Decreases in PAT were only correlated with baseline PAT and the loss in VAT (r = −0.56; P < 0.01; r = 0.42; P < 0.05) but no associations with liver fat or indexes of insulin sensitivity were observed. Improvements in HOMAIR and HOMA2‐%B were only related to the decrease in IHCL (r = 0.62, P < 0.01; r = 0.65, P = 0.002) and decreases in IHCL only correlated with the decrease in VAT (r = 0.61, P = 0.004). In conclusion, cross‐sectionally PAT is correlated with VAT, liver fat, and insulin resistance. Longitudinally, the association between PAT and insulin resistance was lost suggesting no causal relationship between the two.
An Experimental Investigation of the Effect of Altered Auditory Feedback on the Conversational Speech of Adults Who Stutter
Authors: Lincoln Michelle , Packman Ann , Onslow Mark , Jones Mark
Published: March 2010

Purpose

To investigate the impact on percentage of syllables stuttered of various durations of delayed auditory feedback (DAF), levels of frequency-altered feedback (FAF), and masking auditory feedback (MAF) during conversational speech.

Method

Eleven adults who stuttered produced 10-min conversational speech samples during a control condition and under 4 different combinations of DAF, FAF, and MAF. Participants also read aloud in a control condition with DAF and FAF.

Results

A statistically significant difference was found between the NAF conversation condition and the 4 combined altered auditory feedback (AAF) conditions. No statistically significant differences in percentage of syllables stuttered were found in conversation or reading between the control conditions and the FAF/DAF or MAF conditions. The analysis of individual participants' data showed highly individual responsiveness to different conditions.

Conclusions

Participants' varying responses to differing AAF settings likely accounted for the failure to find group differences between conditions. These results suggest that studies that use standard DAF and FAF settings for all participants are likely to underestimate any AAF effect. It is not yet possible to predict who will benefit from AAF devices in everyday situations and the extent of those benefits.
An On-Line Imitative Test of Speech-Pattern Contrast Perception (OlimSpac): Developmental Effects in Normally Hearing Children
Authors: Boothroyd Arthur , Eisenberg Laurie S. , Martinez Amy S.
Published: March 2010

Purpose

The goal was to assess the effects of maturation and phonological development on performance, by normally hearing children, on an imitative test of auditory capacity (On-Line Imitative Test of Speech-Pattern Contrast Perception [OlimSpac]; Boothroyd, Eisenberg, & Martinez, 2006; Eisenberg, Martinez, & Boothroyd, 2003, 2007).

Method

Thirty-four hearing children (aged between 1;8 [years;months] and 6;7) were asked to imitate nonword utterances. Responses were evaluated by a blinded listener in an 8-alternative forced-choice task, giving information on the children’s ability to convey, by imitation, information about 6 binary phonemic contrasts.

Results

Four children declined participation. Among 30 children aged 2;7 or older, performance improved significantly with age and varied with contrast. All children 3 years of age or older attained passing scores (7 or 8 correct responses in 8 binary trials) on at least 5 of the 6 contrasts. Post-alveolar consonant place was the contrast most often failed.

Conclusions

When evaluated on a pass/fail basis, normally hearing children 3 years of age or older are likely to demonstrate auditory perception of most phonemic contrasts using this imitative test. Phonological development and other task-related factors have only a modest effect on performance by normally hearing children after 3 years of age. The effects of hearing loss, hearing age, sensory assistance, and listening experience in children with hearing loss remain to be determined.
Evidence That a Motor Timing Deficit Is a Factor in the Development of Stuttering
Authors: Olander Lindsey , Smith Anne , Zelaznik Howard N.
Published: March 2010

Purpose

To determine whether young children who stutter have a basic motor timing and/or a coordination deficit.

Method

Between-hands coordination and variability of rhythmic motor timing were assessed in 17 children who stutter (4–6 years of age) and 13 age-matched controls. Children clapped in rhythm with a metronome with a 600-ms interbeat interval and then attempted to continue to match this target rate for 32 unpaced claps.

Results

Children who stutter did not significantly differ from children who were typically developing on mean clapping rate or number of usable trials produced; however, they produced remarkably higher variability levels of interclap interval. Of particular interest was the bimodal distribution of the stuttering children on clapping variability. One subgroup of children who stutter clustered within the normal range, but 60% of the children who stutter exhibited timing variability that was greater than the poorest performing nonstuttering child. Children who stutter were not more variable in measures of coordination between the 2 hands (mean and median phase difference between hands).

Conclusion

We infer that there is a subgroup of young stuttering children who exhibit a nonspeech motor timing deficit, and we discuss this result as it pertains to recovery or persistence of stuttering.
Perception of Acoustically Degraded Sentences in Bilingual Listeners Who Differ in Age of English Acquisition
Authors: Shi Lu-Feng
Published: March 2010

Purpose

The effects of acoustic degradation and context use on sentence perception were evaluated in listeners differing in age of English acquisition.

Method

Five groups of 8 listeners, native monolingual (NM), native bilingual (NB), and early, late, and very late non-native bilingual (NN-E, NN-L, and NN-VL, respectively), identified target words in 400 Speech-Perception-in-Noise (SPIN) sentences presented in 8 combinations of noise (+6 vs. 0 dB signal-to-noise ratio), reverberation (1.2 vs. 3.6 s reverberation time), and context (high vs. low predictability).

Results

Separate effects of noise, reverberation, and context were largely level dependent and more significant than their interaction with listeners' age of English acquisition. However, the effect of noise, as well as the combined effect of reverberation and context, was mediated by age of acquisition. NN-VL listeners' performance was significantly compromised in all test conditions. NB, NN-E, and NN-L listeners' use of context, by contrast, deviated substantially from the monolingual normative in difficult listening conditions.

Conclusions

Findings suggest that linguistic background needs to be considered in the understanding of bilingual listeners' context use in acoustically degraded conditions. Direct comparison of early bilingual listeners' performance with monolingual norms may be inappropriate when speech is highly degraded.
Using Language Sampling to Measure Language Growth
Authors: Rojas Raúl , Iglesias Aquiles
Published: March 2010

This article illustrates how speech-language pathologists (SLPs) can use language sampling and growth curve modeling (GCM) to examine the language growth rates of English Language Learners. GCM data on language samples provides SLPs with powerful, new tools to evaluate actual progress over time instead of relying on single, static measurement endpoints to determine typical development.
Existence of the weak solution of coupled time-dependent Ginzburg–Landau equations
Authors: Chen Shuhong , Guo Boling
Published: March 2010

In this paper, we investigate the existence of weak solutions of the coupled time-dependent Ginzburg-Landau equations and establish the global existence of weak solutions to the equations by Galerkin method and compactness theory.
Effect of nitrogen plasma power on defect levels in Ni/n-GaN Schottky diodes grown by molecular beam epitaxy
Authors: Arehart A. R. , Poblenz C. , Speck J. S. , Ringel S. A.
Published: March 2010

The incorporation of deep level defects in n-type GaN grown by plasma assisted molecular beam epitaxy was studied via systematic adjustment of the nitrogen plasma source power from 150 to 400 W while maintaining a constant V/III beam flux ratio. Deep level optical spectroscopy and conventional thermal deep level transient spectroscopy measurements, which together enable deep level detection throughout the GaN band gap, revealed several deep level concentrations that depend strongly on rf-plasma power. The concentrations of the gallium vacancy deep level at EC-2.60 eV and carbon-related point defects with energy levels at EC-3.28 and EC-1.35 eV are found to be very sensitive to the nitrogen source power, increasing by up to 50 times for a corresponding increase in plasma power from 150 to 400 W. The relation between the concentrations of these traps and plasma power follows an Arrhenius-type behavior and is suggestive of plasma damage associated with the energetics of the constituent active nitrogen species. In contrast, two traps at EC-0.86 and EC-0.59 eV did not exhibit a systematic dependence on plasma power, with this difference a result of the dislocation-related nature of these defects.
Computational and experimental studies on the growth of nonpolar surfaces of gallium nitride
Authors: Jindal Vibhu , Shahedipour-Sandvik Fatemeh
Published: March 2010

Surface diffusion of the adatoms strongly influences the surface morphology of thin films. We have carried out density functional theory calculations to study the binding energies, migration pathways, and diffusion barriers for adatoms such as Ga and N on the nonpolar surface such as m- and a-plane GaN surfaces and compare it with the results on c-plane GaN surfaces. A strong anisotropy was observed for the diffusion behavior for Ga adatom on m- and a-plane GaN surfaces with the channels of low diffusion barrier in a- and c-crystallographic directions, respectively. The experimental observation during the metal organic chemical vapor deposition growth of m- and a-plane GaN surfaces show striated surface morphology with the steps oriented in a- and c-crystallographic directions, respectively.
Zener tunneling in semiconductors under nonuniform electric fields
Authors: Vandenberghe William , Sorée Bart , Magnus Wim , Groeseneken Guido
Published: March 2010

Recently, a renewed interest in Zener tunneling has arisen because of its increasing impact on semiconductor device performance at nanometer dimensions. In this paper we evaluate the tunnel probability under the action of a nonuniform electric field using a two-band model and arrive at significant deviations from the commonly used Kane’s model, valid for weak uniform fields only. A threshold on the junction bias where Kane’s model for Zener tunneling breaks down is determined. Comparison with Kane’s model particularly shows that our calculation yields a higher tunnel probability for intermediate electric fields and a lower tunnel probability for high electric fields. When performing a current calculation comparing to the WKB approximation for the case of an abrupt p-n junction significant differences concerning the shape of the I-V curve are demonstrated.
A high resolution scanning electron microscope for in situ investigation of swift heavy ion induced modification of solid surfaces
Authors: Amirthapandian S. , Schuchart F. , Bolse W.
Published: March 2010

A new in situ high resolution electron microscope (HRSEM) setup has been designed and integrated into the materials science beamline (M-branch) of the universal linear accelerator at Gesellschaft für Schwerionenforschung, Darmstadt for in situ investigations of swift heavy ion induced surface modifications. Special ports for in situ experiments are installed at the HRSEM chamber to connect it to the high vacuum beamline, which is equipped with suitable beam control and shaping devices. In order to demonstrate the feasibility and power of this new instrument, first experiments were performed on a 50-nm-thick Fe2O3 film on Si substrate, which exhibited submicrometer size holes due to irradiation induced dewetting in a previous experiment. We have demonstrated that with our new instrument, the development of individual dewetting holes as a function of the ion fluence can be investigated and even the interaction between them can be studied. To illustrate pattern formation during grazing incidence, 3.6 MeV/u X131e ion irradiation was carried out on a 25-nm-thick NiO film on SiO2/Si at a tilt angle of 75°. The SEM image sequence recorded during the experiment reveals the development of a lamellaelike structure also seen before in ex situ experiments. With our new in situ setup, however, we are able to not only investigate the overall average pattern formation, but also to track the formation and decay of individual linking structures, which would be hardly possible in a standard ex situ experiment.
Voltage-time dilemma of pure electronic mechanisms in resistive switching memory cells
Authors: Schroeder Herbert , Zhirnov Victor V. , Cavin Ralph K. , Waser Rainer
Published: March 2010

Metal/insulator/metal thin film stacks showing stable resistive switching are promising candidates for future use as a nonvolatile resistive random access memory, competitive to FLASH and DRAM. Although the switching mechanisms are not completely understood a lot of theories and models try to describe the effects. One of them postulates the trapping and detrapping of electronic charge in immobile traps as the reason for the resistance changes, also known as Simmons & Verderber model. This contribution shows that this “pure electronic” switching mechanism will face a voltage-time dilemma—general to all switching insulators—at conditions competitive to the state-of-the-art FLASH. There is an incompatibility between the long retention time (10 years) and the short READ/WRITE current pulses (tREAD/WRITE≤100 ns) at high densities (area≤100×100 nm2) at low applied voltages (≤1 V). This general dilemma is exemplified in two detailed scenarios with different electronic band and defect properties.
Optical properties of a high-temperature superconductor operating in near zero-permittivity region
Authors: Hsu Heng-Tung , Kuo Fang-Yao , Wu Chien-Jang
Published: March 2010

Optical properties of a high-temperature superconductor in the near-zero-permittivity operation range are theoretically investigated. Investigations are performed through the calculations of optical reflectance over three model structures. First, the calculated wavelength-dependent reflectance for a bulk superconductor occupying half-space shows that the threshold wavelength is strongly influenced by the angle of incidence and the polarization of wave. Second, the reflectance response in a single superconducting slab has a peak at the threshold wavelength for the transverse magnetic (TM) wave, whereas the shape of the peak is very sensitive to the angle of incidence. Finally, reflectance is calculated for a superconductor-dielectric bilayer structure. The results illustrate that the dielectric substrate has a pronounced effect on the reflectance response for both TM and transverse electric waves.
Light emission polarization properties of semipolar InGaN/GaN quantum well
Authors: Huang Hung-Hsun , Wu Yuh-Renn
Published: March 2010

As many reports show that the InGaN quantum wells grown on semipolar substrate have better efficiency in the green spectrum, it is important to understand the light emission properties of these semipolar quantum wells. In this paper, we have studied the optical characteristics of a semipolar InGaN/GaN quantum well with different growth orientations. Also, the most common growth directions such as (101¯3¯) and (112¯2) planes are studied in details. The self-consistent Poisson and 6×6 k⋅p Schrödinger solver has been applied to study the band structure of the semipolar InGaN-based quantum well. We find that the light emission polarization ratio has a very interesting switching behavior under different conditions of indium compositions, quantum well widths, and injection carrier densities. Our results show that the semipolar InGaN quantum well has a potential to be a polarized light source under certain conditions.
Relaxation oscillations in chalcogenide phase change memory
Authors: Nardone M. , Karpov V. G. , Karpov I. V.
Published: March 2010

The results of a comprehensive experimental study of relaxation oscillations in chalcogenide phase change memory are presented. Extending the previous work, voltage and current oscillations were measured over much longer periods of time and with a broad range of applied voltages, load resistances, and device thicknesses. The effects of various reset voltage levels and material types were also considered. Several types of oscillation patterns were observed; most were continuous through the measurement period while others exhibited few or no oscillations. Also observed were two distinct regimes of oscillations; one of stable amplitudes followed by one of decaying amplitudes. The duration of the stable regime and the total time for oscillation decay were found to be directly proportional to the device thickness. In addition, temporal drift of the threshold voltage was observed which provided a method for measuring the variation in the drift coefficient between different materials. A numerical model was developed to simulate oscillations and extrapolate our results to lower circuit time constants. The physical mechanism of oscillations and their stochastic nature are effectively described in the framework of field-induced nucleation, while the transition from stable to decaying amplitudes is attributed to concomitant thermally induced nucleation.
Anomalous current transients in organic field-effect transistors
Authors: Sharma A. , Mathijssen S. G. J. , Cramer T. , Kemerink M. , de Leeuw D. M. , Bobbert P. A.
Published: March 2010

Here we study the origin of the gate bias-stress effect in organic p-type transistors. Based on water-mediated exchange between holes in the semiconductor and protons in the gate dielectric, we predict anomalous current transients for a non-constant gate bias, while ensuring accumulation. When applying a strongly negative gate bias followed by a less negative bias a back-transfer of protons to holes and an increase of the current is expected. We verify this counterintuitive behavior experimentally and can quantitatively model the transients with the same parameters as used to describe the threshold voltage shift.