bluuebunny/crossref_metadata_2025_split huggingface dataset:
Applying approximate LU-factorizations as preconditioners in eight iterative methods for solving systems of linear algebraic equations
Authors: Zlatev Zahari , Georgiev Krassimir 
Published: May 2013

AbstractMany problems arising in different fields of science and engineering can be reduced, by applying some appropriate discretization, either to a system of linear algebraic equations or to a sequence of such systems. The solution of a system of linear algebraic equations is very often the most time-consuming part of the computational process during the treatment of the original problem, because these systems can be very large (containing up to many millions of equations). It is, therefore, important to select fast, robust and reliable methods for their solution, also in the case where fast modern computers are available. Since the coefficient matrices of the systems are normally sparse (i.e. most of their elements are zeros), the first requirement is to efficiently exploit the sparsity. However, this is normally not sufficient when the systems are very large. The computation of preconditioners based on approximate LU-factorizations and their use in the efforts to increase further the efficiency of the calculations will be discussed in this paper. Computational experiments based on comprehensive comparisons of many numerical results that are obtained by using ten well-known methods for solving systems of linear algebraic equations (the direct Gaussian elimination and nine iterative methods) will be reported. Most of the considered methods are preconditioned Krylov subspace algorithms.
Sensitivity studies of pollutant concentrations calculated by the UNI-DEM with respect to the input emissions
Authors: Dimov Ivan , Georgieva Raya , Ostromsky Tzvetan , Zlatev Zahari 
Published: May 2013

AbstractThe influence of emission levels on the concentrations of four important air pollutants (ammonia, ozone, ammonium sulphate and ammonium nitrate) over three European cities (Milan, Manchester, and Edinburgh) with different geographical locations is considered. Sensitivity analysis of the output of the Unified Danish Eulerian Model according to emission levels is provided. The Sobol’ variance-based approach for global sensitivity analysis has been applied to compute the corresponding sensitivity measures. To measure the influence of the variation of emission levels over the pollutants concentrations the Sobol’ global sensitivity indices are estimated using efficient techniques for small sensitivity indices to avoid the effect of loss of accuracy. Theoretical studies, as well as, practical computations are performed in order to analyze efficiency of various variance reduction techniques for computing small indices. The importance of accurate estimation of small sensitivity indices is analyzed. It is shown that the correlated sampling technique for small sensitivity indices gives reliable results for the full set of indices. Its superior efficiency is studied in details.
A numerical study of synchronization in the process of biochemical substance exchange in a diffusively coupled ring of cells
Authors: Mihailović Dragutin , Balaž Igor , Arsenić Ilija 
Published: May 2013

Abstract
In this paper we numerically investigate a model of a diffusively coupled ring of cells. To model the dynamics of individual cells we propose a map with cell affinity, which is a generalization of the logistic map. First, the basic features of a one-cell system are studied in terms of the Lyapunov exponent, Kolmogorov complexity and Sample Entropy. Second, the notion of observational heterarchy, which is a perpetual negotiation process between different levels of the description of a phenomenon, is reviewed. After these preliminaries, we study how the active coupling induced by the consideration of the observational heterarchy modifies the synchronization property of the model with N=100 cells. It is shown numerically that the active coupling enhances synchronization of biochemical substance exchange in several different conditions of cell affinity.
Darboux operators for linear first-order multi-component equations in arbitrary dimensions
Authors: Schulze-Halberg Axel 
Published: May 2013

Abstract
We construct Darboux operators for linear, multi-component partial differential equations of first order. The number of variables and the dimension of the matrix coefficients in our equations are arbitrary. The Darboux operator and the transformed equation are worked out explicitly. We present an application of our formalism to the (1+2)-dimensional Weyl equation.
Effect of environmental conditions and water status on the bioactive compounds of broccoli
Authors: Pék Zoltán , Daood Hussein , Nagyné Magdolna , Neményi András , Helyes Lajos 
Published: May 2013

AbstractFour experiments were carried out in 2010 and 2011 to determine how cultivation period (spring or autumn), harvest season (summer or autumn), and plant water status (irrigated or rainfed) influenced content and composition of broccoli cultivar Parthenon F1 with respect to sulforaphane and phenolics under field conditions in Gödöllő, Hungary. Sulforaphane content was significantly higher in the autumn harvests, regardless of irrigation treatments. Harvest season also influenced total phenolics content, with the highest values occurring in the spring season. Harvest season also affected trolox equivalent antioxidant capacity (TEAC) and this capacity was also the greatest in spring. Caffeic acid glucoside was a major phenolics component in both spring and autumn season harvests. The season and irrigation related changes in other phenolic component contents were also characterised in this study.
Anatomical characteristics and antioxidant ability of Centaurea sadleriana reveals an adaptation towards drought tolerance
Authors: Luković Jadranka , Malenčić Djordje , Zorić Lana , Kodranov Miroslava , Karanović Dunja , Kiprovski Biljana , Boža Pal 
Published: May 2013

AbstractThe lamina, main vein and peduncle anatomical properties of Centaurea sadleriana Janka plants from two populations, were examined using light and scanning electron microscopy. The indumentum was comprised of glandular and non-glandular trichomes of two types. The leaves were amphistomatic, isolateral, with strongly developed palisade tissue. Secretory ducts were observed along the phloem or sclerenchyma of large vascular bundles. Collenchyma alternated with chlorenchyma in the main vein and peduncle. Large groups of strongly lignified sclerenchyma were present along the phloem of peduncle vascular bundles. These features, together with thickened walls of epidermal cells and cuticle, numerous trichomes and thick-walled parenchyma in the perimedullar zone, were perceived as a xeromorphic peduncle structural adaptation. Non-enzymatic antioxidant compounds of phenolic origin were detected in small amounts and their respective content was higher in leaves compared to inflorescences. Compounds of phenolic orgin showed positive correlation with total potenial of antioxidant activity indicated by the DPPH assay. Greater total quantity of polyphenols and tannins was detected in leaves of plants from Zobnatica locality, while leaves of plants from Rimski Sanac were characterized by higher content of total flavonoids and proantocyanidins. Phytochemical analysis showed that dominant secondary biomolecules in inflorescences were phenolic pigments including anthocyanins and leucoanthocyanins, and free quinones in leaves.
Antioxidant enzymes in the liver of Chelidonichthys obscurus from the Montenegrin coastline
Authors: Pavlović Sladjan , Borković-Mitić Slavica , Radovanović Tijana , Perendija Branka , Despotović Svetlana , Gavrić Jelena , Saičić Zorica 
Published: May 2013

AbstractThe activities of antioxidant defence enzymes — total, manganese and copper zinc containing superoxide dismutase (Tot SOD, Mn SOD, CuZn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and biotransformation phase II enzyme glutathione-S-transferase (GST) — in the liver of longfin gurnard (Chelidonichthys obscurus) from the Montenegrin coastline (Adriatic sea) were investigated. The specimens were collected in winter (February) and late spring (May) at two localities: Platamuni (PL, potentially unpolluted) and the Estuary of the River Bojana (EB, potentially polluted). The obtained results show that the activities of Mn SOD, CAT, GSH-Px and GST in winter were significantly lower at EB than at PL. In spring, the activities of CAT and GST were decreased, while GR activity was increased at EB in comparison to PL. The activities of Mn SOD and GST at PL were decreased and GSH-Px, GR and GST activities at EB were increased in spring compared to winter. Our work represents the first study of liver antioxidant enzymes of longfin gurnard from the Montenegrin coastline and reveals that locality, as a variable, has a greater influence on antioxidant enzymes and biotransformation phase II enzyme GST activities compared to season.
The growing abundance of Helicoverpa armigera in Hungary and its areal shift estimation
Authors: Keszthelyi Sándor , Nowinszky László , Puskás János 
Published: May 2013

AbstractThe invasive Cotton Bollworm (Helicoverpa armigera Hübner, Lepidoptera: Noctuidae) has become a serious pest of several agricultural plants since its first mass occurrence in Hungary (1993). During the decades of the species’ presence in the Carpathian Basin, a remarkable fluctuation was detected in its abundance and flight phenology. We analysed long term light trap records and meteorological data to identify the possible factors behind these fluctuations. This study presents an overview of the areal dispersion and the rate of accumulation and flight phenology of this invasive pest, from its first Hungarian mass occurrence until the present, focusing on the influence of climatic factors on the Hungarian distribution of H. armigera. According to our estimation, this pest occupied 94% of the area of Hungary within eight years. There were significant differences in pest pressure by regions, corroborated by the average number of trapped specimens and the regression coefficients. Fluctuations of specimen numbers in the different years are clearly visible in the flight phenology diagrams, which depend on the rate of the growing abundance. The results indicate that abiotic elements may also play a significant role in the areal dispersion of this important invasive insect.
Can enterocins affect phagocytosis and glutathione-peroxidase in rabbits?
Authors: Simonová Monika , Lauková Andrea , Plachá Iveta , Čobanová Klaudia , Strompfová Viola , Szabóová Renáta , Chrastinová Ľubica 
Published: May 2013

AbstractThe gastrointestinal microbiota in rabbits play an important role in protection against potential pathogens via the development of the mucosal immune system. The gut health, including the microbial and immunological stability, is often influenced by exogenous factors, mainly around the weaning period. Therefore, alternative strategies are required to improve the animal’s health. In this study, the diet of rabbits was supplemented with the semi-purified enterocins Ent 2019, Ent M and Ent 4231, produced by bacteriocinogenic strains with probiotic properties, rabbit-derived Enterococcus faecium CCM7420 and non rabbit-derived E. faecium strains AL41 and CCM4231. The phagocytic activity, index of phagocytic activity and the gluthatione-peroxidase enzyme activity in blood were determined during the Ents consumption and also 3 weeks after their cessation. At 21 days into the experiment the highest phagocytic activity was observed in rabbits receiving Ent M. A significant increase in phagocytosis was noted in rabbits with Ent 2019 over the entire experiment. Moreover, a lower gluthatione-peroxidase activity was measured in rabbits receiving Ent M and Ent 2019. No effect of Ent 4231 application on the tested parameters was recorded. The Ent M and Ent 2019 improved the digestive immunity and the host’s defense capacities by stimulating leucocyte phagocytosis, without oxidative stress induction in rabbits.
In vitro and in silico inhibition of angiotensin-converting enzyme by carbohydrates and cyclitols
Authors: Endringer Denise , Oliveira Osmair , Braga Fernão 
Published: May 2013

AbstractFifteen carbohydrates (d-mannose, d-glucose, d-galactose, methyl-α-d-glucose, l-rhamnose, d-xylose, d-fructose, d-arabinose, dulcitol, mannitol, β-maltose, α-lactose, melibiose, sucrose, and raffinose) and four cyclitols [l-(+)-bornesitol, myo-inositol, per-O-acetyl-1-l-(+)-bornesitol, and quinic acid] were assayed for in vitro ACE inhibition. Of these molecules, per-O-Acetyl-1-l-(+)-bornesitol, quinic acid, methyl-α-d-glucose, d-rhamnose, raffinose, and the disaccharides were determined to be either inactive or weak ACE inhibitors, whereas l-(+)-bornesitol, d-galactose, d-glucose, and myo-inositol exhibited significant ACE inhibition. Molecular docking studies were performed to investigate interactions between active compounds and human ACE (Protein Data Bank, PDB 1O83). The results of various calculations showed that all active sugars bind to the same enzyme region, which is a tunnel directed towards the active site. With the exception of myo-inositol (K i = 13.95 μM, IC50 = 449.2 μM), the active compounds presented similar K i and IC50 values. d-Galactose (K i = 19.6 μM, IC50 = 35.7 μM) and l-(+)-bornesitol (K i = 25.3 μM, IC50 = 41.4 μM) were the most active compounds, followed by d-glucose (K i = 32.9 μM, IC50 = 85.7 μM). Our docking calculations are in agreement with the experimental data and show a new binding region for sugar-like molecules, which may be explored for the development of new ACE inhibitors.
Sexual function in older adults following thoracolumbar to pelvic instrumentation for spinal deformity
Authors: Hamilton D. Kojo , Smith Justin S. , Nguyen Tanya , Arlet Vincent , Kasliwal Manish K. , Shaffrey Christopher I. 
Published: May 2013

Object
Sexual function is an often-overlooked aspect of health-related quality of life among older adults treated for spinal deformity. The authors' objective was to assess sexual function among older adults following thoracolumbar fusion with pelvic fixation for spinal deformity.

Methods
This was a retrospective review of consecutive older adults (≥50 years) treated with posterior thoracolumbar instrumentation (including pelvic fixation) for spinal deformity and with a minimum 18-month follow-up. Patients completed the Changes in Sexual Function Questionnaire-14 (CSFQ-14), Oswestry Disability Index (ODI), and 12-Item Short-Form Health Survey (SF-12).

Results
Sixty-two patients (45 women and 17 men) with a mean age of 70 years (range 50–83 years) met the inclusion criteria. Eight women did not complete all questionnaires and were excluded from the subanalysis. The mean number of instrumented levels was 9.8 (range 6–18), and the mean follow-up was 36 months (range 19–69 months). Based on the CSFQ-14, 13 patients (24%) had normal sexual function, and 8 (15%), 10 (19%), and 23 (42%) had mild, moderate, and severe dysfunction, respectively. Thirty-nine percent of patients reporting severe sexual dysfunction did not have available partners—23% because of a partner's death and 16% because of a partner's illness)—or had significant medical comorbidities of their own (48%). Thirty-nine percent of assessed patients had either no or only mild sexual dysfunction. Patients with minimal or mild disability tended to have no or mild sexual dysfunction.

Conclusions
The authors of this study assessed sexual function in older adults following surgical correction of spinal deformity that included posterior instrumented fusion and iliac bolts. Nearly 40% of assessed patients had either no or only mild sexual dysfunction, suggesting that despite an older age and extensive spinopelvic instrumentation, it remains very possible to maintain or achieve satisfactory sexual function.
Réseaux et subventions : les pièges cachés des énergies intermittentes
Authors: Gay Aurélien , Glita Marc 
Published: May 2013

Le développement des énergies alternatives intermittentes se heurte à des difficultés économiques et politiques souvent insoupçonnées. Après la crise de l’euro, l’Europe connaîtra-t-elle celle de l’électricité ?
Quels métiers pour la communication numérique des organisations touristiques ?
Authors: Alexandre-Bourhis Nathalie , Khalla Said , Rouvrais-Charron Chantal 
Published: May 2013

Cette étude vise à dessiner les contours des métiers présents et futurs qui sont liés à la communication numérique. Après avoir décrit le contexte spécifique du secteur touristique, particulièrement touché par l’évolution des NTIC, l’article présente les résultats d’une étude qualitative réalisée auprès de trente et un professionnels du secteur (directeurs d’organisation touristique privée ou publique et chargés de communication). Quatre métiers majeurs émergent de l’analyse : community manager, chargé d’accueil numérique, animateur numérique d’un territoire et veilleur stratégique. La prise en compte de ces métiers semble incontournable pour répondre aux besoins à venir du secteur.
Structure des coûts d'alimentation en eau potable : une analyse sur un panel d'unités de production ivoiriennes
Authors: Diakité Daouda , Thomas Alban 
Published: May 2013

Dans cet article, nous analysons la structure des coûts d’alimentation en eau potable des villes de Côte d’Ivoire à partir d’un panel des centres de production. Considérant les services d’eau comme des monopoles multi-produits fournissant conjointement deux biens (volumes d’eau facturés et volumes d’eau perdus), nous estimons une fonction de coût translog multi-produits sur la base de la dualité entre fonctions de production et de coût. Les différentes mesures de rendements calculées révèlent que le service d’eau moyen ivoirien produit dans la zone des rendements constants. Cependant, en classant les services en petits, moyens et grands selon différents critères, il apparaît clairement que l’opérateur a un avantage économique à accroître sa production et les connections dans la plupart des petits et moyens services. Aussi, la présence d’économies de gamme révèle que la production conjointe des deux biens considérés dans certaines proportions est plus bénéfique que l’amélioration du rendement du réseau. Enfin, les évaluations des coûts estimés font apparaître un coût marginal supérieur en moyenne aux prix marginaux des premières tranches de la grille tarifaire. Classification JEL : C33, D24, Q25.
Le couplage « responsabilité sociale des entreprises » et « développement durable » : mise en perspective, enjeux et limites
Authors: Quairel Françoise , Capron Michel 
Published: May 2013

En Europe, les concepts de responsabilité sociale des entreprises (RSE) et de développement durable (DD) sont fortement liés. Or cette approche de la RSE ne s’est construite que depuis une dizaine d’années et elle n’est pas universellement partagée. L’objectif de cet article est de présenter les différentes étapes du processus de « couplage » entre RSE et DD, de mettre en lumière le rôle des « entrepreneurs institutionnels » (WBCSD et SustainAbility), qui ont contribué à l’institutionnalisation des grandes entreprises comme acteurs du DD et d’en analyser les enjeux et les limites. L’enjeu majeur du couplage RSE-DD est le rôle politique attribué aux grandes entreprises dans la régulation internationale en l’absence d’une véritable gouvernance mondiale et d’un droit international pour les entreprises.
Fracture aperture and fill characterization in a limestone quarry using GPR thin‐layer AVA analysis
Authors: Kana Aisha A. , West L. Jared , Clark Roger A. 
Published: May 2013

The detection and characterization of fractures is important in many engineering practices e.g., rock fall assessment, quarry rock quality determination and mine roof and tunnel stability. Fractures may provide suitable contrasts in electrical properties for detection by GPR instruments. Their ability to reflect radar waves and the dependence of this reflectivity on fracture properties (aperture and fill) makes the GPR method a promising tool for rock fracture characterization. Doing so successfully requires quantification of the reflectivity, reflection coefficient, R, of individual fractures and its variation with incidence angle (AVA), or in practice, offset. Measuring the full AVA response using Common Mid Point (CMP) surveys enables simultaneous estimation of fracture aperture and fill permittivity, difficult to achieve with Common Offset (CO) profiling which does not evaluate angle dependence. This paper reports on AVA analysis carried out on CMP data acquired with 500 MHz antennae over Carboniferous Limestone with horizontal bedding plane fractures in Yorkshire, United Kingdom. Using the transverse electric (TE) polarization mode, data were collected at a sampling interval of 0.05 ns for offsets at 0.04 m steps from 0.37–16.05m.The recorded amplitude is related to the reflection coefficient but is also influenced by other factors we eliminated by making some simplifying assumptions and amplitude corrections. We assume frequency‐independent electrical properties, constant antenna coupling with the ground surface, constant losses associated with transmission losses through any interfaces above the target reflection for the range of offsets considered and a flat homogeneous surface over which measurements are made. Amplitudes were corrected for conductive attenuation, spherical spreading and antenna patterns, which we measured through transillumination surveys across limestone boulders and numerical modelling using the GprMax 3D modelling code. To constrain fracture aperture and fill permittivity, we use the least squares fit of normalized reflection coefficient curves to corrected CMP amplitudes. The analysis allowed characterization of the (bedding plane) fracture fill relative permittivity (~7.8) and aperture (~0.043 m, ~0.2 at 500 MHz). The values obtained are consistent with field observations of fracture fill, corresponding to a mixture of clays and calcite.
Cutting Edge: Receptors for C3a and C5a Modulate Stability of Alloantigen-Reactive Induced Regulatory T Cells
Authors: van der Touw William , Cravedi Paolo , Kwan Wing-hong , Paz-Artal Estela , Merad Miriam , Heeger Peter S. 
Published: May 2013

Abstract
CD4+Foxp3+ regulatory T cells (Treg) are critical regulators of immune homeostasis and self-tolerance. Whereas thymic-derived or natural Treg stably express Foxp3, adaptive or induced Treg (iTreg) generated from peripheral CD4 T cells are susceptible to inflammation-induced reversion to pathogenic effector T cells. Building upon our previous observations that T cell–expressed receptors for C3a (C3aR) and C5a (C5aR) drive Th1 maturation, we tested the impact of C3aR/C5aR signaling on induction and stability of alloreactive iTreg. We observed that genetic deficiency or pharmacological blockade of C3aR/C5aR signaling augments murine and human iTreg generation, stabilizes Foxp3 expression, resists iTreg conversion to IFN-γ/TNF-α–producing efffector T cells, and, as a consequence, limits the clinical expression of graft-versus-host disease. Taken together, the findings highlight the expansive role of complement as a crucial modulator of T cell alloimmunity and demonstrate proof-of-concept that targeting C3a/C3aR and C5a/C5aR interactions could facilitate iTreg-mediated tolerance to alloantigens in humans.