2,047 research outputs found
Optimal Parameter Extraction Scheme of Current Sources and Bias Dependent Elements for HBT by searching the whole unknown Parameter Space
New analytical expressions for the dynamic resistance,transconductance,base-collector internal capacitance,and base-emitter internal capacitance are derived.And a new scheme,to extract the current source parameters,thermal parameter,and small signal parameters at multiple bias points on the normal active region,is developed.The proposed parameter extraction method is robust and very fast.Based on these equations, we propose a new scheme to find out the optimal solution by searching for a full-unknown parameter space.The search space corresponds to 1.17x10 8 points on the error surface, and it takes 12.6 hours to get an optimal model parameters using a 2GHz-desktop PC.This scheme is helpful for the modeling of HBT excluding the local minimum problem in the gradient optimization method and the inaccuracies in the direct extraction method
Improving BOLD sensitivity with real-time multi-echo echo-planar imaging - Towards a cleaner neurofeedback signal
Real-time functional magnetic resonance imaging (rtfMRI) suffers from known issues related to T2*-weighted single-echo echo-planar imaging (EPI). These include image dropout in areas with increased local magnetic susceptibility susceptibility gradients; suboptimal whole-brain blood oxygen level-dependent (BOLD) contrast due to average T2*-weighting; and confounders like subject motion and physiology. During fMRI neurofeedback a metric calculated from real-time brain activity is presented visually to the subject in the scanner. To prevent sham feedback, new methods should focus on improving BOLD signal quality in real-time. In this work, presented as a poster at the 11th annual meeting of the ISMRM Benelux chapter (17 January 2019), we present our work on real-time multi-echo fMRI and its usefulness in increasing the temporal signal-to-noise ratio (tSNR) of rtfMRI
Mutation analysis using the restriction site mutation (RSM) assay
The restriction site mutation RSM assay see Steingrimsdottir et al. H. Steingrimsdottir, D. Beare, J. Cole, J.F.M. Leal, Ž. Ž w
T. Kostic, J. Lopez-Barea, G. Dorado, A.R. Lehmann, Development of new molecular procedures for the detection of
genetic alteration in man, Mutat. Res. 353 1996 pp. 109–121 for a review has been developed as a genotypic mutation Ž . x .
detection system capable of identifying mutations occurring in restriction enzyme sites of genomic DNA. Here we will
report the steps taken to overcome some of the initial problems of the assay, namely the lack of quantitative data and limited
sensitivity, the aim being to achieve a methodology suitable for the study of low dose chemical exposures. Quantitative data
was achieved in the RSM assay by the inclusion of an internal standard molecule in the PCR amplification stage, thus
allowing the calculation of both spontaneous and induced mutation frequencies. The sensitivity of the assay was increased
through the discovery that intron sequences of genomic DNA accumulated more mutations in vivo compared to the exons,
presumably due to differential selective pressure within genes G.J.S. Jenkins, I.deG. Mitchell, J.M. Parry, Enhanced w
restriction site mutation RSM analysis of 1,2-dimethylhydrazine-induced mutations, using endogenous Ž . p53 intron
sequences, Mutagenesis 12 1997 pp. 117–123 . This increased sensitivity was examined by applying the RSM assay to Ž . x
analyse the persistence of N-ethyl-N-nitrosourea ENU -induced mutations in mice testes. Germ line mutations were sought Ž .
in testes DNA 3, 10 and 100 days after ENU treatment. Mutations were detected in exons and especially intron regions, the
intron mutations were more persistent, still being detected 100 days post-chemical treatment. Assignment of these mutations
as ENU induced was complicated in some cases where the spontaneous mutation level was high. This theme of mutation
persistence was further investigated by studying the presence of 4-nitroquinoline-1-oxide 4-NQO -induced DNA mutations Ž .
in vitro. This study also analysed the relationship between DNA adduct formation and DNA mutation induction by the
concurrent RSM analysis and 32P post-labelling analysis of 4-NQO treated human fibroblasts. The results demonstrated that
early DNA mutations detected 4 days post-treatment by the RSM assay were probably ex vivo mutations induced by Taq
polymerase misincorporation of 4-NQO adducted DNA, due to the maximum levels of 4-NQO adducts being present at this
time point. A later mutational peak, after the adduct level had declined, was assumed to be due to DNA sequence changes
produced in the fibroblasts by the in vivo processing of DNA adducts
An array of fabry-perot optical-channels for biological fluids analysis
This paper describes a biosystem (biological system) used to measure the concentration of biochemical substances in urine, serum,
plasma or cerebrospinal fluid. Rather than just one channel, it comprises 16 optical-channels that enable the measurement of the concentration
of 16 different biochemical substances. An array of 16 optical filters based on Fabry-Perot thin-films optical resonators has
been designed. Each optical-channel is sensitive in a single wavelength with a full-width-half-maximum (FWHM) of 7 nm. The filter
fabrication requires only four masks, used with different etch time. A commercially available band-pass optical filter with a band-pass
wavelength in 450–650 nm is used. The biosystem requires only a white light source for illumination due the use of selective optical
filters.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/1281/2000, POCTI/33747/ESE/1999 – Fundo Europeu para o Desenvolvimento Regional
Evaluation of golden needle mushroom (Flammulina velutipes) stem waste on pullet performance and immune response
The driving force behind the interest in using natural herbs in poultry production is to eliminate the use of low-dose antibiotics. Therefore, this study was carried out to investigate the effect of Flammulina velutipes mushroom waste (FVW) on performance parameters, relative organ weight, apparent nutrient retention, excreta composition, immune response and serum immunity in pullets. A total of 360 x 10-week-old ISA Brown pullets were randomly assigned to five equal treatment groups, with nine replications of eight birds for each treatment. The dietary treatments included a standard basal diet as control; antibiotic (0.05% flavomycin); 2% FVW; 4% FVW; and 6% FVW. The total experimental duration was 42 days, from 10 weeks to 16 weeks old. Final live weight was higher in FVW groups than in the control and antibiotic groups. No differences were found for average daily feed intake, average daily weight gain and feed conversion ratio during the entire study period. Proventriculus weight and bursa weight were higher in FVW groups. No differences were observed for other inner relative organ weights (liver weight, gizzard weight spleen and abdominal fat weight) compared with the control and antibiotic groups. Dietary inclusion of FVW increased dry matter, crude protein and ether extract retention compared with control and antibiotic groups. Excreta dry matter content was higher and pH lower, in the FVW groups than in the control and antibiotic groups. Antibody titres against Newcastle disease, Infectious bronchitis and Avian influenza virus vaccines were higher in FVW groups. Serum immunoglobulin parameters (IgA, IgG, IgM) were higher in FVW than in the control and antibiotic groups. Flammulina velutipes mushroom waste can be used at inclusion levels up to 6% in pullet rations for better immune response and nutrient retention without hampering normal growth performance.Keywords: Antibody titres, apparent nutrient retention, excreta dry matter, serum immunit
Highly reproducible alkali metal doping system for organic crystals through enhanced diffusion of alkali metal by secondary thermal activation
In this paper, we report an efficient alkali metal doping system for organic single crystals. Our system employs an enhanced diffusion method for the introduction of alkali metal into organic single crystals by controlling the sample temperature to induce secondary thermal activation. Using this system, we achieved intercalation of potassium into picene single crystals with closed packed crystal structures. Using optical microscopy and Raman spectroscopy, we confirmed that the resulting samples were uniformly doped and became K2picene single crystal, while only parts of the crystal are doped and transformed into K2picene without secondary thermal activation. Moreover, using a customized electrical measurement system, the insulator-to-semiconductor transition of picene single crystals upon doping was confirmed by in situ electrical conductivity and ex situ temperature-dependent resistivity measurements. X-ray diffraction studies showed that potassium atoms were intercalated between molecular layers of picene, and doped samples did not show any KH- nor KOH-related peaks, indicating that picene molecules are retained without structural decomposition. During recent decades, tremendous efforts have been exerted to develop high-performance organic semiconductors and superconductors, whereas as little attention has been devoted to doped organic crystals. Our method will enable efficient alkali metal doping of organic crystals and will be a resource for future systematic studies on the electrical property changes of these organic crystals upon doping. © 2018 The Author(s
Self-consistent Ornstein-Zernike approximation for three-dimensional spins
An Ornstein-Zernike approximation for the two-body correlation function
embodying thermodynamic consistency is applied to a system of classical
Heisenberg spins on a three-dimensional lattice. The consistency condition
determined in a previous work is supplemented by introducing a simplified
expression for the mean-square fluctuations of the spin on each lattice site.
The thermodynamics and the correlations obtained by this closure are then
compared with approximants based on extrapolation of series expansions and with
Monte Carlo simulations. The comparison reveals that many properties of the
model, including the critical temperature, are very well reproduced by this
simple version of the theory, but that it shows substantial quantitative error
in the critical region, both above the critical temperature and with respect to
its rendering of the spontaneous magnetization curve. A less simple but
conceptually more satisfactory version of the SCOZA is then developed, but not
solved, in which the effects of transverse correlations on the longitudinal
susceptibility is included, yielding a more complete and accurate description
of the spin-wave properties of the model.Comment: 32 pages, 12 figure
The program is the model: Enabling [email protected]
The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-36089-3_7Revised Selected Papers of 5th International Conference, SLE 2012, Dresden, Germany, September 26-28, 2012The increasing application of Model-Driven Engineering in a wide range of domains, in addition to pure code generation, raises the need to manipulate models at runtime, as part of regular programs. Moreover, certain kinds of programming tasks can be seen as model transformation tasks, and thus we could take advantage of model transformation technology in order to facilitate them.
In this paper we report on our works to bridge the gap between regular programming and model transformation by enabling the manipulation of Java APIs as models. Our approach is based on the specification of a mapping between a Java API (e.g., Swing) and a meta-model describing it. A model transformation definition is written against the API meta-model and we have built a compiler that generates the corresponding Java bytecode according to the mapping. We present several application scenarios and discuss the mapping between object-oriented meta-modelling and the Java object system. Our proposal has been validated by a prototype implementation which is also contributed.Work funded by the Spanish Ministry of Economy and Competitivity (TIN2011-24139), and the R&D programme of Madrid Region (S2009/TIC-1650)
Fractal Weyl law for Linux Kernel Architecture
We study the properties of spectrum and eigenstates of the Google matrix of a
directed network formed by the procedure calls in the Linux Kernel. Our results
obtained for various versions of the Linux Kernel show that the spectrum is
characterized by the fractal Weyl law established recently for systems of
quantum chaotic scattering and the Perron-Frobenius operators of dynamical
maps. The fractal Weyl exponent is found to be that
corresponds to the fractal dimension of the network . The
eigenmodes of the Google matrix of Linux Kernel are localized on certain
principal nodes. We argue that the fractal Weyl law should be generic for
directed networks with the fractal dimension .Comment: RevTex 6 pages, 7 figs, linked to arXiv:1003.5455[cs.SE]. Research at
http://www.quantware.ups-tlse.fr/, Improved version, changed forma
Influence of season of birth, sex and paternal line on growth performance and carcass traits in pigs
Participants in the pig production industry focus on feed and feed additives to improve growth performance and meat quality of pigs. Consequently, the Rural Development Administration of the Republic of Korea produced a new paternal line to improve economic traits in pigs. However, there is an absence of information on pig traits with regard to season and sex, and a comparison between the new paternal line and past paternal lines. Therefore, the authors conducted this study to investigate the influence of season of birth, sex and paternal line on growth performance and carcass traits in pigs. A total of 2888 piglets ((Landrace × Yorkshire) × Darby Duroc (DD) or Chookjin Duroc (CD)) with an average age of three weeks were tested for 22 weeks during the four season of the year (spring 608 piglets, summer 404 piglets, autumn 576 piglets and winter 1300 piglets). The bodyweights (BW) of individual pig were recorded, and feed consumption was recorded at weeks 2, 12 and 22, to determine growth performance. At reaching market weight, backfat thickness was determined at the last rib area. Meat was graded according to the criteria of the slaughterhouse. There were no significant differences in growth performance and carcass traits between sexes. The CD line crossbred pig had a significant higher BW at 16 weeks, and higher carcass trait values at 22 weeks than the DD line. During weeks 8 to 16 the CD line crossbred pigs showed a tendency of an increased average daily gain (ADG) and gain : feed (G : F) ratio compared with the DD line. Furthermore, pigs born in spring had significant lower ADG, average daily feed intake (ADFI) and carcass trait values than born in the other seasons. In conclusion, the new paternal line (Chookjin Duroc) improved growth performance and carcass traits compare with the DD line.Keywords: sex, growth, terminal sire, meat quality, backfat thicknes
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