bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluctuation‐induced conductivity of (YCe)Ba2Cu3O7–δ superconductor
Authors: Ferreira Talita Rosas , Pinheiro Lincoln Brum de Leite Gusmão , Júnior Pedro Rodrigues , Serbena Francisco Carlos , Jurelo Alcione Roberto 
Published: February 2011

AbstractSystematic measurements of the in‐plane and out‐of‐plane in conductivity fluctuations have been used to investigate the role of the cerium ion on the splitting of the pairing transition. This splitting, associated with a phase separation, was firstly observed in single crystals and polycrystalline samples of Y1–xPrxBa2Cu3O7–δ. Considering that Ce is the rare‐earth element most easily ionized to the +4 state and that in melt‐textured sample, it is possible to observe anisotropic effects, we examined the effect of this ion in the Y1–xCexBa2Cu3O7–δ compound. We prepared three different samples: polycrystalline, pure melt‐textured and Ce‐doped melt‐textured. Melt‐textured samples were prepared using the top‐seeding growth technique and the polycrystalline sample by the standard solid‐state reaction technique. The samples were characterized by X‐ray diffraction, scanning electron microscopy (SEM) and electrical resistivity. To identify power‐law divergences in the conductivity, the results were analyzed in terms of the temperature derivative of the resistivity (${\rm d}\rho /{\rm d}T$) and of the logarithmic temperature derivative of the conductivity (${-} {\rm d}{\ln} (\Delta \sigma )/{\rm d}T$). In the normal phase, Gaussian and critical regimes were clearly seen for melt‐textured samples and no important differences between pure and Ce‐doped samples were observed. On the other hand, for the polycrystalline sample and from the critical exponent analysis, a splitting of the pairing transition was clearly observed. It is suggested that the occurrence of a phase separation and its association with Ce doping as already observed for Pr‐doped samples.
Kondo effect in a double quantum dot interferometer with Rashba spin–orbit interaction
Authors: Liu Xiao‐Jie , Yin Hai‐Tao , Wan Wei‐Long , Li Hua , Wang Xian‐Zhang , Yao Cheng‐Bao 
Published: February 2011

AbstractElectronic transport through a double quantum dot interferometer with Rashba spin–orbit interaction is investigated. By means of the slave‐boson mean‐field approximation and Green function technique, we calculated the local density of states (DOS) and the linear conductance in the Kondo regime at zero temperature. It is shown that the local DOS and the linear conductance of each spin component can be tuned by the Rashba spin–orbit interaction with help of the magnetic flux. In particular, by modulating the strength of the Rashba spin–orbit interaction properly, only one spin component electron can be allowed to transport through this structure.
Bandgap modulations of silicon carbon nanoribbons by transverse electric fields: A theoretical study
Authors: Zheng Fang‐Ling , Zhang Yan , Zhang Jian‐Min , Xu Ke‐Wei 
Published: February 2011

AbstractUnder external transverse electronic fields, the electronic and magnetic properties of silicon carbon nanoribbons with zigzag edge (ZSiCNRs) and armchair edge (ASiCNRs) are studied by using the first‐principles projector augmented wave (PAW) potential within the density‐function theory (DFT) framework. Our results for the narrow ZSiCNRs by the VASP computer code are in good agreement with those of Lou and coworkers. Thus, in this paper we showed the new results for the wide ZSiCNRs as a complementary study as well as for the narrow and wide ASiCNRs. The ground state of the ZSiCNR is a ferrimagnetic semiconductor with two different direct bandgaps for the spin‐up and the spin‐down channels near the zone boundary Z, and converts to a ferromagnetic metal when a suitable transverse electric field is applied. However, the ground state of the ASiCNR is a nonmagnetic semiconductor and its bandgap decreases with increasing absolute value of the field strength. After a suitable critical field, the ASiCNR changes to a metal, and the larger ribbon width, the larger decrease rate and thus the smaller critical field.
Luminescence imaging for inline characterisation in silicon photovoltaics
Authors: Trupke Thorsten , Nyhus Jørgen , Haunschild Jonas 
Published: February 2011

AbstractLuminescence imaging is a very rapid technique for the characterisation of silicon samples. Megapixel luminescence images on silicon bricks, unprocessed wafers, partially processed wafers and fully processed cells can be captured with acquisition times of typically a few seconds or less than one second. A number of specific luminescence imaging applications have been developed over the last three years, allowing quantitative spatial information to be gained about a variety of crucial material and device parameters. This paper reviews some of the intriguing possibilities for inline monitoring in PV production at an early stage of production that result from the above mentioned short measurement times. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum confinement in germanium nanocrystal thin films
Authors: Holman Zachary C. , Kortshagen Uwe R. 
Published: February 2011

AbstractThin films of semiconductor nanocrystals with tunable optical properties are promising materials for new device applications, but progress has been slow for group IV materials. We report absorption measurements near the absorption edge of thin films of germanium nanocrystals synthesized in a plasma and impacted onto substrates. Band gaps extracted from the absorption data vary from the near‐bulk value of 0.73 eV for 9.0 nm nanocrystals to over 1.0 eV for 4.7 nm nanocrystals. These values are comparable to those reported for isolated, non‐interacting germanium nanocrystals, indicating minimal loss of quantum confinement upon dense film formation. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Power of tests for comparing trend curves with application to national immunization survey (NIS)
Authors: Zhao Zhen 
Published: February 2011

AbstractTo develop statistical tests for comparing trend curves of study outcomes between two socio‐demographic strata across consecutive time points, and compare statistical power of the proposed tests under different trend curves data, three statistical tests were proposed. For large sample size with independent normal assumption among strata and across consecutive time points, the Z and Chi‐square test statistics were developed, which are functions of outcome estimates and the standard errors at each of the study time points for the two strata. For small sample size with independent normal assumption, the F‐test statistic was generated, which is a function of sample size of the two strata and estimated parameters across study period. If two trend curves are approximately parallel, the power of Z‐test is consistently higher than that of both Chi‐square and F‐test. If two trend curves cross at low interaction, the power of Z‐test is higher than or equal to the power of both Chi‐square and F‐test; however, at high interaction, the powers of Chi‐square and F‐test are higher than that of Z‐test. The measurement of interaction of two trend curves was defined. These tests were applied to the comparison of trend curves of vaccination coverage estimates of standard vaccine series with National Immunization Survey (NIS) 2000–2007 data. Copyright © 2011 John Wiley & Sons, Ltd.
Ultrafast Large‐Area Micropattern Generation in Nonabsorbing Polymer Thin Films by Pulsed Laser Diffraction
Authors: Verma Ankur , Sharma Ashutosh , Kulkarni Giridhar U. 
Published: February 2011

AbstractAn ultrafast, parallel, and beyond‐the‐master micropatterning technique for ultrathin (30−400 nm) nonabsorbing polymer films by diffraction of laser light through a 2D periodic aperture is reported. The redistribution of laser energy absorbed by the substrate causes self‐organization of polymer thin films in the form of wrinklelike surface relief structures caused by localized melting and freezing of the thin film. Unlike conventional laser ablation and laser writing processes, low laser fluence is employed to only passively swell the polymer as a pre‐ablative process without loss of material, and without absorption/reaction with incident radiation. Self‐organization in the thin polymer film, aided by the diffraction pattern, produces microstructures made up of thin raised lines. These regular microstructures have far more complex morphologies than the mask geometry and very narrow line widths that can be an order of magnitude smaller than the openings in the mask. The microstructure morphology is easily modulated by changing the film thickness, aperture size, and geometry, and by changing the diffraction pattern.
Location of Biomarkers and Reagents within Agarose Beads of a Programmable Bio‐nano‐chip
Authors: Jokerst Jesse V. , Chou Jie , Camp James P. , Wong Jorge , Lennart Alexis , Pollard Amanda A. , Floriano Pierre N. , Christodoulides Nicolaos , Simmons Glennon W. , Zhou Yanjie , Ali Mehnaaz F. , McDevitt John T. 
Published: February 2011

AbstractThe slow development of cost‐effective medical microdevices with strong analytical performance characteristics is due to a lack of selective and efficient analyte capture and signaling. The recently developed programmable bio‐nano‐chip (PBNC) is a flexible detection device with analytical behavior rivaling established macroscopic methods. The PBNC system employs ≈300 μm‐diameter bead sensors composed of agarose “nanonets” that populate a microelectromechanical support structure with integrated microfluidic elements. The beads are an efficient and selective protein‐capture medium suitable for the analysis of complex fluid samples. Microscopy and computational studies probe the 3D interior of the beads. The relative contributions that the capture and detection of moieties, analyte size, and bead porosity make to signal distribution and intensity are reported. Agarose pore sizes ranging from 45 to 620 nm are examined and those near 140 nm provide optimal transport characteristics for rapid (<15 min) tests. The system exhibits efficient (99.5%) detection of bead‐bound analyte along with low (≈2%) nonspecific immobilization of the detection probe for carcinoembryonic antigen assay. Furthermore, the role analyte dimensions play in signal distribution is explored, and enhanced methods for assay building that consider the unique features of biomarker size are offered.
Enhancement of Cellulolytic Enzyme Activity by Clustering Cellulose Binding Domains on Nanoscaffolds
Authors: Kim Do‐Myoung , Umetsu Mitsuo , Takai Kyo , Matsuyama Takashi , Ishida Nobuhiro , Takahashi Haruo , Asano Ryutaro , Kumagai Izumi 
Published: February 2011

AbstractCellulose, one of the most abundant carbon resources, is degraded by cellulolytic enzymes called cellulases. Cellulases are generally modular proteins with independent catalytic and cellulose‐binding domain (CBD) modules and, in some bacteria, catalytic modules are noncovalently assembled on a scaffold protein with CBD to form a giant protein complex called a cellulosome, which efficiently degrades water‐insoluble hard materials. In this study, a catalytic module and CBD are independently prepared by recombinant means, and are heterogeneously clustered on streptavidin and on inorganic nanoparticles for the construction of artificial cellulosomes. Heteroclustering of the catalytic module with CBD results in significant improvements in the enzyme’s degradation activity for water‐insoluble substrates. In particular, the increase of CBD valency in the cluster structure critically enhances the catalytic activity by improving the affinity for substrates, and clustering with multiple CBDs on CdSe nanoparticles generates a 7.2‐fold increase in the production of reducing sugars relative to that of the native free enzyme. The multivalent design of substrate‐binding domain on clustered cellulases is important for the construction of the artificial cellulosome, and the nanoparticles are an effective scaffold for increasing the valence of CBD in clustered cellulases. A new design is proposed for artificial cellulosomes with multiple CBDs on noncellulosome‐derived scaffold structures.
Knowledge as cheating: A metaphorical analysis of the concept of ‘best practice’
Authors: Falconer James 
Published: February 2011

AbstractWell entrenched after many years, and perhaps just as well obfuscated, the flawed concept of ‘best practice’ remains a guiding precept of management. Best practice is flawed because it acts as a placeholder for proper management practice, displacing accountability for effectiveness and fit. Best practice is flawed, further, because it supplants strategy, adopting solutions out of convenience or copying them reactively, and supplants innovation, allowing ‘the best we know about’, ‘the best we've come across’, or even ‘the best we've done before’ to be adequate. Best practice considers the world predictable, and discounts the emergence of better, novel ideas. In organizations that rely on best practice, knowledge management tactics focus on building repositories to house best practice artefacts. This fosters the ready harvesting of old ideas and reusing them in new applications. Over time, this leads to fewer and fewer new ideas, little improvement through reuse, and eventually diminishing marginal returns across the whole corpus. This, and a limited value (generation) proposition based on what is effectively ‘used’ knowledge, means that best practice represents a relatively poor investment from an intellectual capital perspective. Using metaphorical analysis to unpack the best practice orientation toward knowledge holistically reveals a cogent underpinning metaphor, knowledge as cheating, which is then analysed. The metaphor knowledge as exploration is then offered as a foil, with all the foregoing in mind, and subjected to similar, and comparative, analysis. It is found superior in both an absolute and a relative sense. Copyright © 2011 John Wiley & Sons, Ltd.
Science, decision‐making and development: managing the risks of climate variation in less‐industrialized countries
Authors: Kandlikar Milind , Zerriffi Hisham , Ho Lem Claudia 
Published: February 2011

AbstractThis article addresses the role of scientific knowledge in decision‐making with respect to climate variability and change in the developing world, with a focus on scientific capacity. We propose a ‘systemic’ view of scientific capacity for studying the relationship between science and decision‐making vis‐à‐vis climate variation, one that encompasses knowledge production, as well as its translation for and use in decision‐making. We analyze the challenges faced by developing countries in building capacity on each of these elements. Case studies on the production and use of scientific information for societal decision‐making at three distinct timescales—the weekly scale (Hurricanes in the North Indian Ocean), the seasonal scale (Climate Variability in the Sahel), and the decadal/century scale (Climate Change Impacts on Small Island States) are used to elucidate the scale and complexity of capacity building challenges. We argue that capacity building for coping with the impacts of climate change is interwoven with the capacity needed for meeting the challenges of development, particularly those related to short‐term climate and weather variation. Any serious attempt to build scientific capacity for decision‐making vis‐à‐vis climate change will need to embrace a ‘developmentalist’ position. WIREs Clim Change 2011 2 201–219 DOI: 10.1002/wcc.98This article is categorized under:

Climate and Development > Knowledge and Action in Development
Social Status of Climate Change Knowledge > Climate Science and Decision Making
Channel capacity of OFDM systems employing diversity in fading environments
Authors: Le Khoa N. , Dabke Kishor P. 
Published: February 2011

ABSTRACTThis paper derives capacity of a fading channel with orthogonal frequency division multiplexing (OFDM) transmission employing diversity techniques and adaptive policies involving (i) power and rate, (ii) optimal rate and (iii) channel inversion with fixed rate. Two major diversity techniques are considered (i) maximal ratio combining (MRC) and (ii) selective combining (SC). Closed‐form expressions and/or bounds on various channel capacity with OFDM transmission under different scenarios are derived. Simulation results are given. Copyright © 2011 John Wiley & Sons, Ltd.
An adaptive channel preemption model for small‐cell embedded large‐cellular networks
Authors: Sheu Tsang‐Ling , Lin Chia‐Nan 
Published: February 2011

ABSTRACTIn this paper, we present an analytical model of adaptive channel preemption (ACP) for small‐cell embedded large‐cellular (SCELC) networks. An SCELC network consists of a fixed base station (FBS) with large coverage and many embedded base stations (EBS) with relatively small coverage. Channel capacity in an FBS cell may become insufficient when traffic is unexpectedly increased particularly in some special occasion. This paper considers two aspects of dynamically allocating channels for an SCELC network. First, by increasing one or more EBS cells within an FBS cell, the proposed ACP can reduce blocking probability of new calls. Second, to reduce dropping probability of handoff calls, the proposed ACP allows a handoff call to preempt an on‐going call, when the latter is located in an EBS cell or in the overlapping area of two adjacent FBS cells. For the purpose of performance evaluation, we build an analytical model with 4‐tuple Markov chains. Numerical results reveal that embedding one or more EBS cells inside an FBS cell needs to be done carefully since it results in a tradeoff between the reduction of new‐call blocking probability and the increase of handoff‐call dropping probability. Copyright © 2011 John Wiley & Sons, Ltd.
Improving quality of service in WiMAX communication at vehicular speeds: a new call admission control solution
Authors: Ahmad Iftekhar , Habibi Daryoush 
Published: February 2011

ABSTRACTCall admission control (CAC) scheme serves as a useful tool for the WiMAX technology, which ensures that resources are not overcommitted and thereby, all existing connections enjoy guaranteed quality of service (QoS). CAC schemes largely rely on readily available information like currently available resources and bandwidth demand of the new call while making an acceptance or rejection decision once a new request arrives. Since wireless channels are not as reliable as wired communication, CAC scheme in WiMAX communication faces a serious challenge of making a right estimate of the usable channel capacity (i.e., effective throughput capacity) while computing the available resources in various communication scenarios. Existing CAC schemes do not consider the impact of mobility at vehicular speeds when computing the usable link capacity and available resources. The main limitation of such CAC scheme is that when a mobile node moves at a slower speed and makes a connection request to the base station (BS), the BS evaluates the situation based on the currently available information. The BS in such cases, is short‐sighted and often overestimates the available resources as it completely ignores the scenario when the SS reaches its top speed within a very short time after a CAC decision is made, causing a significant drop in usable throughput. In this paper, we address this limitation of existing WiMAX CAC schemes and propose a new CAC scheme that estimates the usable link capacity for WiMAX communication at vehicular speeds and uses this information while making a CAC decision. We also present a CAC scheme that takes the speed distribution model of a mobile node into account during the CAC decision making process. Simulation results confirm that the proposed scheme achieves lower dropping rate and improved QoS compared to existing schemes. Copyright © 2011 John Wiley & Sons, Ltd.
Language production and working memory in classic galactosemia from a cognitive neuroscience perspective: future research directions
Authors: Timmers Inge , den van Hurk Job , Di Salle Francesco , Rubio‐Gozalbo M. Estela , Jansma Bernadette M. 
Published: February 2011

AbstractMost humans are social beings and we express our thoughts and feelings through language. In contrast to the ease with which we speak, the underlying cognitive and neural processes of language production are fairly complex and still little understood. In the hereditary metabolic disease classic galactosemia, failures in language production processes are among the most reported difficulties. It is unclear, however, what the underlying neural cause of this cognitive problem is. Modern brain imaging techniques allow us to look into the brain of a thinking patient online ‐ while she or he is performing a task, such as speaking. We can measure indirectly neural activity related to the output side of a process (e.g. articulation). But most importantly, we can look into the planning phase prior to an overt response, hence tapping into subcomponents of speech planning. These components include verbal memory, intention to speak, and the planning of meaning, syntax, and phonology. This paper briefly introduces cognitive theories on language production and methods used in cognitive neuroscience. It reviews the possibilities of applying them in experimental paradigms to investigate language production and verbal memory in galactosemia.
Features and outcome of galactokinase deficiency in children diagnosed by newborn screening
Authors: Hennermann Julia B. , Schadewaldt Peter , Vetter Barbara , Shin Yoon S. , Mönch Eberhard , Klein Jeannette 
Published: February 2011

AbstractGalactokinase deficiency (GALK‐D), an autosomal recessive disorder in the Leloir pathway, results in accumulation of galactose, galactitol, and galactonate and leads to early onset of juvenile bilateral cataract. Highest incidence of GALK‐D is found in Romani populations. The migration wave due to the Yugoslavian civil war has changed the spectrum of inborn errors of metabolism within Europe. Hence, newborn screening (NBS) in the Berlin region, performed from 1991 until 2010 in 683,675 neonates, revealed an increased incidence of GALK‐D of 1:40,000, comparable to that of galactose‐1‐phosphate‐uridyltransferase deficiency. A total of 44% of GALK‐D patients were of Romani origin. All patients of Bosnian or Serbian origin were homozygous for the Romani founder mutation p.P28T. Detection of GALK‐D by NBS and early start of galactose‐restricted diet resulted in regression or prevention of cataracts. Slight cataracts without visual impairment occurred in 50% of the patients, 56% of whom were noncompliant. Further clinical symptoms, e.g., hypoglycemia, mental retardation, microcephaly, and failure to thrive, were associated with noncompliance. With treatment, galactose in blood decreased from 8,892 ± 5,243 to 36.5 ± 49.3 μmol/l, galactose in urine from 31,820 ± 32,103 to 30.0 ± 36.1 μmol/mmol creatinine, galactitol in RBC from 1,584 ± 584 to 12.3 ± 9.4 μmol/l, and galactitol in urine from 11,724 ± 4,496 to 236 ± 116 μmol/mmol creatinine. This is the first presentation of outcome and clinical features in GALK‐D patients diagnosed by NBS. As our data suggest, GALK‐D should be considered for inclusion in NBS in populations expected to have substantial numbers of GALK‐D carriers, e.g., Yugoslavian immigrants.