bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel delay‐derivative‐dependent stability criteria using new bounding techniques
Authors: Zhang Xian‐Ming , Han Qing‐Long 
Published: April 2012

SUMMARYThis paper studies the stability of linear systems with interval time‐varying delays. By constructing a new Lyapunov–Krasovskii functional, two delay‐derivative‐dependent stability criteria are formulated by incorporating with two different bounding techniques to estimate some integral terms appearing in the derivative of the Lyapunov–Krasovskii functional. The first stability criterion is derived by using a generalized integral inequality, and the second stability criterion is obtained by employing a reciprocally convex approach. When applying these two stability criteria to check the stability of a linear system with an interval time‐varying delay, it is shown through some numerical examples that the first stability criterion can provide a larger upper bound of the time‐varying delay than the second stability criterion. Copyright © 2012 John Wiley & Sons, Ltd.
Passive and active acoustics using an autonomous wave glider
Authors: Bingham Brian , Kraus Nicholas , Howe Bruce , Freitag Lee , Ball Keenan , Koski Peter , Gallimore Eric 
Published: April 2012

AbstractThe recently developed wave glider has the potential to be an effective unmanned platform for acoustic applications. We present the results of a variety of experiments that quantify this potential. The radiated self‐noise of the autonomous platform is evaluated using an integrated passive acoustic recorder during a set of field trials off the coast of Hawaii. We present the radiated noise spectra from these trials to illustrate the dependence on hydrophone location and sea state. Using the same instrumentation, we demonstrate the ability of a modified wave glider to detect marine mammals using passive acoustic monitoring techniques. We also evaluate the performance of the wave glider operating as an active acoustic gateway, highlighting the potential of this platform to serve as a navigation reference and communications relay for scientific, industrial, and military subsea assets. To demonstrate the potential of the wave glider platform to support acoustic navigation, we assess the performance of time‐of‐flight range estimation and seafloor transponder localization. These tests were performed using commercial off‐the‐shelf acoustic positioning hardware integrated with the wave glider to illustrate that the low self‐noise of the wave glider makes it possible to achieve acoustic positioning performance similar to previously reported results. Finally, we show that the glider can operate as a station‐keeping surface communications gateway and provide recommendations for its use. © 2012 Wiley Periodicals, Inc.
Direct Volume Rendering Methods for Cell Structures
Authors: Martišek* Dalibor , Martišek Karel 
Published: April 2012

SummaryThe study of the complicated architecture of cell space structures is an important problem in biology and medical research. Optical cuts of cells produced by confocal microscopes enable two‐dimensional (2D) and three‐dimensional (3D) reconstructions of observed cells. This paper discuses new possibilities for direct volume rendering of these data. We often encounter 16 or more bit images in confocal microscopy of cells. Most of the information contained in these images is unsubstantial for the human vision. Therefore, it is necessary to use mathematical algorithms for visualization of such images. Present software tools as OpenGL or DirectX run quickly in graphic station with special graphic cards, run very unsatisfactory on PC without these cards and outputs are usually poor for real data. These tools are black boxes for a common user and make it impossible to correct and improve them. With the method proposed, more parameters of the environment can be set, making it possible to apply 3D filters to set the output image sharpness in relation to the noise. The quality of the output is incomparable to the earlier described methods and is worth increasing the computing time. We would like to offer mathematical methods of 3D scalar data visualization describing new algorithms that run on standard PCs very well. SCANNING 34: 367‐377, 2012. © 2012 Wiley Periodicals, Inc.
The dynamics of wealth, profit, and sustainable advantage
Authors: Jacobides Michael G. , Winter Sidney G. , Kassberger Stefan M. 
Published: April 2012

AbstractThis paper shows how idiosyncratic resources can drive sustained profitability and persistent heterogeneity under competitive conditions. Generic inputs purchased in the market become idiosyncratic resources as the result of firms' investments in customization. Analytically, we show how heterogeneous firms coexist in equilibrium as a function of customization costs. Computationally, we show that sustainable profits can emerge without ‘monopolistic’ imperfections. We consider how capability heterogeneity, resource customization cost, and ease of expansion interact to drive short‐run and sustainable profits. Our results illustrate that sustainable profits may represent a small part of the total wealth created over time by a firm or industry, and that changes in factors shaping a sector's evolutionary trajectory may be more important than changes in factors that determine profits' ultimate sustainability. Copyright © 2012 John Wiley & Sons, Ltd.
High‐Throughput Transfection of Interfering RNA into a 3D Cell‐Culture Chip
Authors: Zhang Haiyuan , Lee Moo‐Yeal , Hogg Michael G. , Dordick Jonathan S. , Sharfstein Susan T. 
Published: April 2012

AbstractA method for high‐throughput retroviral transfection of genes and interfering RNA into 3D cell‐culture microarrays is described. 3D cultures more closely mimic the in vivo cellular milieu, thus providing cellular responses to genetic manipulation more similar to the in vivo situation than 2D cultures. This technique is applied to transfect several “toxic” short‐hairpin RNAs (shRNAs) into 3D cell cultures. It is demonstrated that the toxicity is similar to that obtained by conventional (non‐high‐throughput) retroviral transfection of cells grown in similar 3D culture microarrays.
Fabrication of a Carbon‐Nanotube‐Based Field‐Effect Transistor by Microcontact Printing
Authors: Mehlich Jan , Miyata Yasumitsu , Shinohara Hisanori , Ravoo Bart Jan 
Published: April 2012

AbstractThe fabrication of a field‐effect transistor with both channel material and source and drain electrodes made from carbon nanotubes (CNTs) through patterned deposition of CNT films by microcontact printing is described. Surfactant‐dispersed single‐walled CNTs are first separated into semiconducting and metallic fractions by gel filtration. The semiconducting and metallic CNTs are then sequentially transferred by dendrimer‐coated polydimethylsiloxane stamps onto dendrimer‐coated silicon wafers following a printing protocol optimized for this purpose. The resulting CNT micropatterns are visualized by atomic force microscopy. Semiconducting as well as metallic CNTs preserve their characteristic electronic properties within the transferred films. A device composed of a rather thick (ca. 5 nm) and densely patterned film of metallic CNTs cross‐printed on top of a thinner (ca. 1.5 nm) and less dense film of semiconducting CNTs shows the typical properties of a field‐effect transistor with the metallic CNT stripes as electrodes, the semiconductive CNT stripes as channel material, and the silicon substrate as gate electrode.
Cancer Prognostics by Direct Detection of p53‐Antibodies on Gold Surfaces by Impedance Measurements
Authors: Prats‐Alfonso Elisabet , Sisquella Xavier , Zine Nadia , Gabriel Gemma , Guimerà Anton , del Campo F. Javier , Villa Rosa , Eisenberg Adam H. , Mrksich Milan , Errachid Abdelhamid , Aguiló Jordi , Albericio Fernando 
Published: April 2012

AbstractThe identification and measurement of biomarkers is critical to a broad range of methods that diagnose and monitor many diseases. Serum auto‐antibodies are rapidly becoming interesting targets because of their biological and medical relevance. This paper describes a highly sensitive, label‐free approach for the detection of p53‐antibodies, a prognostic indicator in ovarian cancer as well as a biomarker in the early stages of other cancers. This approach uses impedance measurements on gold microelectrodes to measure antibody concentrations at the picomolar level in undiluted serum samples. The biosensor shows high selectivity as a result of the optimization of the epitopes responsible for the detection of p53‐antibodies and was validated by several techniques including microcontact printing, self‐assembled‐monolayer desorption ionization (SAMDI) mass spectrometry, and adhesion pull‐off force by atomic force microscopy (AFM). This transduction method will lead to fast and accurate diagnostic tools for the early detection of cancer and other diseases.
Incidence and Risk Factors of the Intraoperative Localization Failure of Nonpalpable Breast Lesions by Radio‐guided Occult Lesion Localization: A Retrospective Analysis of 579 Cases
Authors: Bernardi Sergio , Bertozzi Serena , Londero Ambrogio P. , Gentile Giuliana , Giacomuzzi Francesco , Carbone Arnalda 
Published: April 2012

AbstractBackgroundThe radio‐guided occult lesion localization (ROLL) technique allows the identification of nonpalpable breast lesions by means of the preoperative, intratumoral injection of a radiotracer. Our study aimed to determine the incidence and risk factors of ROLL failure.MethodsWe collected data about all women who underwent ROLL in our department from 2002 to 2009, focusing on patient characteristics such as breast size and density, lesion size, localization, histology, radiologist, and surgeon experience. Data were analyzed using R v2.10.1, considering p < 0.05 significant.ResultsA total of 579 ROLLs were performed on 555 women with a mean age of 58.7 (±10.96) years. Incidence of ROLL failure at the first intervention was 4 % (23/579). Through monovariate analysis, ROLL failure was significantly influenced by stereotactic mammography‐guided procedure, invasive tumors, pathological and radiological lesion size ≤5 mm, and the lesion’s location in the central or upper breast quadrants. Through multivariate analysis, the most predictive factors for ROLL failure were as follows: lesion localization in the central quadrant, lesion radiological size ≤5 mm, and radiologist inexperience.ConclusionsThe main risk factors for ROLL failure were the radiologist’s inexperience, lesion size ≤5 mm, and its localization in the central subareolar quadrant, probably due to an unfavorable radiological and surgical reaching of the breast area.
A generalized model for overdispersed count data
Authors: Okamura Hiroshi , Punt André E. , Amano Tatsuya 
Published: April 2012

AbstractOverdispersed count data are very common in ecology. The negative binomial model has been used widely to represent such data. Ecological data often vary considerably, and traditional approaches are likely to be inefficient or incorrect due to underestimation of uncertainty and poor predictive power. We propose a new statistical model to account for excessive overdisperson. It is the combination of two negative binomial models, where the first determines the number of clusters and the second the number of individuals in each cluster. Simulations show that this model often performs better than the negative binomial model. This model also fitted catch and effort data for southern bluefin tuna better than other models according to AIC. A model that explicitly and properly accounts for overdispersion should contribute to robust management and conservation for wildlife and plants.
The elemental shear dynamo
Authors: McWilliams James C. 
Published: April 2012

AbstractA quasi-linear theory is presented for how randomly forced, barotropic velocity fluctuations cause an exponentially growing, large-scale (mean) magnetic dynamo in the presence of a uniform parallel shear flow. It is a ‘kinematic’ theory for the growth of the mean magnetic energy from a small initial seed, neglecting the saturation effects of the Lorentz force. The quasi-linear approximation is most broadly justifiable by its correspondence with computational solutions of nonlinear magnetohydrodynamics, and it is rigorously derived in the limit of small magnetic Reynolds number, ${\mathit{Re}}_{\eta } \ll 1$. Dynamo action occurs even without mean helicity in the forcing or flow, but random helicity variance is then essential. In a sufficiently large domain and with a small seed wavenumber in the direction perpendicular to the mean shearing plane, a positive exponential growth rate $\gamma $ can occur for arbitrary values of ${\mathit{Re}}_{\eta } $, viscous Reynolds number ${\mathit{Re}}_{\nu } $, and random-force correlation time ${t}_{f} $ and orientation angle ${\theta }_{f} $ in the shearing plane. The value of $\gamma $ is independent of the domain size. The shear dynamo is ‘fast’, with finite $\gamma \gt 0$ in the limit of ${\mathit{Re}}_{\eta } \gg 1$. Averaged over random realizations of the forcing history, the ensemble-mean magnetic field grows more slowly, if at all, compared to the r.m.s. field (magnetic energy). In the limit of small ${\mathit{Re}}_{\eta } $ and ${\mathit{Re}}_{\nu } $, the dynamo behaviour is related to the well-known alpha–omega ansatz when the force is slowly varying ($\gamma {t}_{f} \gg 1$) and to the ‘incoherent’ alpha–omega ansatz when the force is more rapidly fluctuating.
Stratified wake of a tilted cylinder. Part 1. Suppression of a von Kármán vortex street
Authors: Meunier Patrice 
Published: April 2012

AbstractThis experimental and numerical study considers the two-dimensional stability of a circular cylinder wake, whose axis is tilted with respect to a stable density gradient. When the Reynolds number increases, the wake transitions from a steady flow to a periodic von Kármán vortex street as in a homogeneous fluid. However, the presence of a moderate stratification delays the appearance of the von Kármán vortex street, in agreement with the stabilization of shear flows by a density gradient. This stabilization, which does not occur for a vertical cylinder, increases with the tilt angle of the cylinder and is maximum for a horizontal cylinder. The critical Reynolds number increases when the stratification increases and diverges at a Froude number of order one for a horizontal cylinder. This critical Reynolds number can be predicted using the Richardson number based on the projection of the gravity and the density gradient in the direction of the shear, as was proposed by Candelier (J. Fluid Mech., vol. 685, pp. 191–201) for a tilted stratified jet. This picture is completely different for a strongly stratified wake since a new unstable mode appears, creating a von Kármán vortex street with a smaller Strouhal number. This surprising result is due to the presence of tilted vortices with no vertical velocity, i.e. with horizontal elliptic streamlines. This mode occurs in a band of Froude numbers which becomes smaller and smaller when the tilt angle increases, and eventually disappears for a horizontal cylinder. The presence of the tilt has thus a large impact on the structure of the wake at small Froude numbers and might need to be taken into account in geophysical flows.
Overview of worldwide diversity ofDiaphorina citriKuwayama mitochondrial cytochrome oxidase 1 haplotypes: two Old World lineages and a New World invasion
Authors: Boykin L.M. , De Barro P. , Hall D.G. , Hunter W.B. , McKenzie C.L. , Powell C.A. , Shatters R.G. 
Published: April 2012

AbstractRelationships among worldwide collections ofDiaphorina citri(Asian citrus psyllid) were analyzed using mitochondrial cytochrome oxidase I (mtCOI) haplotypes from novel primers. Sequences were produced from PCR amplicons of an 821bp portion of the mtCOI gene usingD. citrispecific primers, derived from an existing EST library. An alignment was constructed using 612bps of this fragment and consisted of 212 individuals from 52 collections representing 15 countries. There were a total of eight polymorphic sites that separated the sequences into eight different haplotypes (Dcit-1 through Dcit-8). Phylogenetic network analysis using the statistical parsimony software, TCS, suggests two major haplotype groups with preliminary geographic bias between southwestern Asia (SWA) and southeastern Asia (SEA). The recent (within the last 15 to 25 years) invasion into the New World originated from only the SWA group in the northern hemisphere (USA and Mexico) and from both the SEA and SWA groups in the southern hemisphere (Brazil). In only one case, Reunion Island, did haplotypes from both the SEA and SWA group appear in the same location. In Brazil, both groups were present, but in separate locations. The Dcit-1 SWA haplotype was the most frequently encountered, including ~50% of the countries sampled and 87% of the total sequences obtained from India, Pakistan and Saudi Arabia. The second most frequently encountered haplotype, Dcit-2, the basis of the SEA group, represented ~50% of the countries and contained most of the sequences from Southeast Asia and China. Interestingly, only the Caribbean collections (Puerto Rico and Guadeloupe) represented a unique haplotype not found in other countries, indicating no relationship between the USA (Florida) and Caribbean introductions. There is no evidence for cryptic speciation forD. citribased on the COI region included in this study.
Genetic improvement of bread wheat yield and associated traits in Spain during the 20th century
Authors: SANCHEZ-GARCIA M. , ROYO C. , APARICIO N. , MARTÍN-SÁNCHEZ J. A. , ÁLVARO F. 
Published: April 2012

SUMMARYA collection of 26 wheat genotypes widely grown in Spain during the 20th century was evaluated in eight contrasting environments in order to quantify breeding achievements in yield and associated traits. From 1930 to 2000, yield increased at a rate of 35·1 kg/ha/yr or 0·88%/yr, but estimations of relative genetic gain (RGG) were environment-dependent. RGG estimated for yield were positively associated with the average minimum daily temperatures from sowing to heading in the testing environments (R2 = 0·81;P < 0·01). The number of grains/spike and the number of spikes/m2increased at a rate of 0·60%/yr and 0·30%/yr, respectively, while grain weight remained unchanged. The present study detected two main episodes of yield improvement during the century. The first one coincided with the introduction, during the 1950s, of the first improved cultivars derived from intra-specific crosses, which increased the yield of landraces by 30% due to an increase ofc. 58% in the number of grains/spike, accompanied by a 16% reduction in grain weight. These initial cultivars (termed ‘old-bred’ in a previous study by Sanchez-Garciaet al. 2012) exhibited a higher harvest index (HI), increased from 0·25 to 0·40, but maintained the same aboveground biomass at maturity as the landraces (despite reducing both plant height and the number of tillers/plant) due to increases in the proportion of tillers bearing spikes. The second yield gain occurred after the introduction, in the early 1970s, of semi-dwarf germplasm from CIMMYT (International Maize and Wheat Improvement Centre) and some French cultivars. This new germplasm further reduced plant height, improved HI up to 0·45 and increased the number of tillers/plant while maintaining their rate of fertility, thus resulting in a yield gain ofc. 37%. The cultivars released during the last decade of the century did not contribute to significant yield improvements.
Impact of hydrology and effluent quality on the management of woodchip pads for overwintering cattle. II. Effluent analysis and nutrient balance
Authors: JACKSON D. R. , CHADWICK D. R. , CROOKES M. , SAGOO E. , SMITH K. A. 
Published: April 2012

SUMMARYWoodchip pads can be a sustainable alternative to the overwintering of stock on grassland or in conventional housing and can offer benefits in improved animal performance, improved health and environmentally sustainable options for the management of the effluent resulting from the animal excreta (dung, urine and rainfall over the pad). Detailed observations were made on effluent flow and quality from woodchip pads on two commercial farms in the UK, one in Powys (Wales) and the other in Leicestershire (England), over a period of 8 months in 2009/10. Flow data and hydrological characteristics, reported in the companion to the current paper (Jackson & Smith 2012), were combined with the results of effluent sample and soiled woodchip analyses, together with records of animal numbers and activity on the pads, to calculate nutrient fluxes and nutrient balances across the pad for defined periods. Nutrient balances showed that, of the estimated nutrient inputs in animal excreta deposited on the pad, only 0·05–0·10 of the N and P were contained in the effluent draining from the pad, with the rest (>0·90 of N and P inputs) retained in the solids accumulating in the surface layers of soiled woodchip, ‘spent timber residues’ (STR). The STR was similar in analysis to straw-based farmyard manure (FYM), high in organic N, and land spreading of this material should be managed in a similar way to FYM. It also appears suitable for application to grassland, except when based on coarse woodchips. These results confirm the hypothesis that the effluent draining from the pads should be considered as consistently similar to dirty water rather than slurry, as in the current rules associated with Nitrate Vulnerable Zones (NVZs) in England and Wales.
Understanding the role of social capital for mental wellbeing among older adults
Authors: FORSMAN A. K. , HERBERTS C. , NYQVIST F. , WAHLBECK K. , SCHIERENBECK I. 
Published: April 2012

ABSTRACTPrevious research applying quantifiable measurements has established significant positive associations between social capital and mental health in older adults. This study aimed to obtain a deeper understanding of the causal mechanisms of social capital affecting mental wellbeing among older people. The study is based on two independent qualitative data materials collected through two focus group interviews and an open-ended question included in a Finnish population-based postal survey. The findings indicate that informal social contacts such as family members and life-long relationships between friends impact the experienced mental wellbeing among older adults due to shared life events, social support, mutual appreciation and trust, as well as a sense of belonging through common social activities. Hence, this study challenges Putnam's idea of social capital as a collective concept focusing on formal contacts and the benefits on a collective level. In addition, the findings highlight the obstacles specific to older adults in maintaining social networks and participation, which should be considered in order to promote mental health in later life.
Second and third harmonics generation in the interaction of strongly magnetized dense plasma with an intense laser beam
Authors: Ghorbanalilu Mohammad 
Published: April 2012

AbstractThe goal of this theory is to study the conversion of a fraction of a laser beam to its phase-mismatch second and third harmonics. This conversion takes place by focusing an intense laser beam into a transversely magnetized plasma, as a nonlinear medium. The influence of the polarization field is considered, however, the plasma density is below the critical density. It has already been revealed that for dense plasma, the second and third harmonics efficiencies decreased with density increasing in the presence of a sufficiently strong magnetic field. This result is in contrast to the under dense and weakly magnetized plasma, which the harmonics efficiencies increased with density increasing. It is shown that the harmonics radiation cut-off, when the magnetic field increases up until the saturation strength Bsat. In addition, the results indicated that the average phase-mismatch third harmonic conversion efficiency is a little smaller than the phase-match case reported for non-magnetized plasma.