Search

In this work, we consider the nonlinear dynamics and computational aspects for non-negative solutions of one-dimensional doubly nonlocal fractional conservation laws ∂ t u + ∂ x [ u Λ α - 1 (κ (x) H u) ] = 0 and ∂ t u - ∂ x [ u Λ α - 1 (κ (x) H u) ] = 0 , where Λ α - 1 denotes the fractional Riesz transform, H denotes the Hilbert transform, and κ (x) denotes the spatial variability of the permeability coefficient in a porous medium. We construct an unconventional Lagrangian–Eulerian scheme, based on the concept of no-flow curves, to handle the doubly nonlocal term, under a weak CFL stability condition, which avoids the computation of the derivative of the nonlocal flux function. Primarily, we develop a feasible computational method and derive error estimates of the approximations of the Riesz potential operator Λ α - 1 . Secondly, we undertake a formal numerical-analytical study of initial value problems associated with such doubly nonlocal models to add insights into the role of nonlinearity and coefficient κ (x) in the composition between the Hilbert transform and the fractional Riesz potential. Numerical experiments are presented to show the performance of the approach. [ABSTRACT FROM AUTHOR]

In this work, we construct and analyze a new fully discrete Lagrangian-Eulerian numerical method for the treatment of dynamics of conservation laws with nonlocal flux and influence of the source term in the solution. The scheme is based on the improved concept of no-flow curves. We use the recent results of S. Blandin & P. Goatin (2016), [Numer. Math. 132, 217-241], to obtain a BV estimate for the new fully discrete (explicit) Lagrangian-Eulerian scheme with a rigorous analysis to prove its convergence for the entropic solution. We also derive a weak CFL-type stability condition that does not require the derivative of the nonlocal flux as is the case for classical schemes. As an application of the proposed approach, we present a combined analytical-numerical study on the interplay between local and nonlocal conservation laws motivated by dynamics of differential equations such as traffic flow and related problems. For a suitable exponential kernel ω η of class C 2 , we present theoretical and numerical evidence that the limit of solutions to the nonlocal equation coincides with the unique entropy-admissible solution of the scalar conservation law ρ t + (ρ m v (q)) x = 0 . It should be emphasized that hypotheses on the solution were verified numerically only. In this regard, the flux function f (ρ) = ρ m v (q) satisfies q (x , t) = ∫ x x + η ω η (x - y) ρ (y , t) d y , for an integer 1 ≤ m , where ω η is unitary (integral equals to 1) and non-increasing kernel such that ω η (s) = 1 (1 - e - 1 / η 2 ) η 2 e - s / η 2 for every s ∈ R . It turns out that we also use recent results of A. Bressan & W. Shen (2020), [Arch. Rational Mech. Anal., 237, 1213-1236] and A. Bressan & W. Shen (2021), [Communications in Mathematical Sciences 19(5) 1447 - 1450], as foundations of the Lagrangian-Eulerian approach for nonlocal conservation laws. [ABSTRACT FROM AUTHOR]

This paper investigates the existence, nonexistence, and qualitative properties of p-harmonic functions in the upper half-space R + N (N ≥ 3) satisfying nonlinear boundary conditions for 1 < p < N . Moreover, the symmetry of positive solutions is shown by using the method of moving planes. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the chondrotoxic effects of intra-articular use of TXA 20 mg/kg and/or 0.35% PVPI on knee joint cartilage in an experimental model of rabbits. Methods: Forty-four male New Zealand adult rabbits were randomly assigned to four groups (control, tranexamic acid (TXA), povidone-iodine (PVPI), and PVPI + TXA). The knee joint cartilage was accessed through an arthrotomy and exposed to physiological saline SF 0.9% (control group), TXA, PVPI, and PVPI followed by TXA. Sixty days after surgical procedure, the animals were sacrificed and osteochondral specimens of the distal femur were obtained. Histological sections of cartilage from this area were stained with hematoxylin/eosin and toluidine blue. The following cartilage parameters were evaluated by the Mankin histological/histochemical grading system: structure, cellularity, glycosaminoglycan content in the extracellular matrix, and integrity of the tidemark. Results: The isolated use of PVPI causes statistically significant changes in cartilage cellularity (p-value = 0.005) and decrease glycosaminoglycan content (p = 0.001), whereas the isolated use of TXA decreased significantly the glycosaminoglycan content (p = 0.031). The sequential use of PVPI + TXA causes more pronounced alterations in the structure (p = 0.039) and cellularity (p = 0.002) and decreased content of glycosaminoglycans (p < 0.001) all with statistical significance. Conclusion: Data suggest that intra-articular use of tranexamic acid 20 mg/kg and intraoperative lavage with 0.35% povidone-iodine solution for three min are toxic to the articular cartilage of the knee in an experimental in vivo study in rabbits. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to establish some weighted Sobolev inequalities, which are the borderline cases of the Sobolev embedding on the upper half-space. We use this inequality to derive a weighted Trudinger–Moser-type inequality. Our proofs rely on a simple decomposition which is rearrangement free. As an application of our results, we address the existence of solutions for a class of elliptic problems with exponential critical growth. [ABSTRACT FROM AUTHOR]

Introduction: Total knee arthroplasty is used to treat end-stage knee osteoarthritis with great results. Tourniquet use has become popular over the years because of its various benefits, but the literature regarding functional outcomes, pain and rehabilitation and comparison between tourniquet use and improvement cement penetration and overall improve fixation is limited. The authors proposed a hypothesis that cementation quality, and clinical outcomes can be influenced by tourniquet technique. Methods: Fifty patients were allocated randomly in two groups: (1) tourniquet was inflated throughout all the procedure and (2) only during skin incision and cementation. Radiolucent lines were analyzed by two and independent examiners, using the The Knee Society Roentgenographic Evaluation and Scoring System. The functional scores used were the Oxford knee score and improvement in visual pain scale (VAS). Results: After a mean follow-up period of 2.4 ± 0.2 years, no difference was observed regarding partial use of tourniquet in the cementation quality (p value > 0.05). There was no difference between groups regarding gender, age, knee side, Visual VAS, Oxford Score, total range-of-motion (ROM), knee extension and knee flexion (p value > 0.05). Conclusions: No difference was attained regarding functional outcomes and cementation quality regarding two different tourniquet protocols. [ABSTRACT FROM AUTHOR]

This article investigates the connections between Wheat Pattern refined earthenwares produced in São Paulo and the Italian immigration farming colony of northeast Rio Grande do Sul during the first decades of the twentieth century. It explores the wheat symbology to discuss the role that these wares exerted in the construction of an Italian identity in southern Brazil appealing to those immigrants´ core values: agricultural labor, family life, and Catholic religiosity. Meanwhile, the fascist regime diffused these same values to build a trans-Atlantic national identity which bounded immigrants to their homeland as civilization carriers for the New Roman Empire designed by Mussolini. [ABSTRACT FROM AUTHOR]

The interaction of many-body systems with intense light pulses may lead to novel emergent phenomena far from equilibrium. Recent discoveries, such as the optical enhancement of the critical temperature in certain superconductors and the photo-stabilization of hidden phases, have turned this field into an important research frontier. Here, we demonstrate nonthermal charge-density-wave (CDW) order at electronic temperatures far greater than the thermodynamic transition temperature. Using time- and angle-resolved photoemission spectroscopy and time-resolved X-ray diffraction, we investigate the electronic and structural order parameters of an ultrafast photoinduced CDW-to-metal transition. Tracking the dynamical CDW recovery as a function of electronic temperature reveals a behaviour markedly different from equilibrium, which we attribute to the suppression of lattice fluctuations in the transient nonthermal phonon distribution. A complete description of the system's coherent and incoherent order-parameter dynamics is given by a time-dependent Ginzburg-Landau framework, providing access to the transient potential energy surfaces. Photo-induced phase transitions triggered by an ultrafast excitation cannot be described within the quasi-equilibrium framework. Here, using time-resolved experimental probes, the authors report a transient charge-density-wave order in TbTe3 and describe it using a model with a non-equilibrium transition temperature. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study is to provide an updated meta-analysis comparing the benefits and clinical outcomes between high flexion (HF)-TKA and standard (S)-TKA.Materials and Methods: A detailed database analysis was carried out using Web of Science, PubMed, EMBASE, Cochrane Library, MEDLINE and Clinicaltrial.gov, to identify eligible studies. The meta-analysis and sensitivity analysis were performed using Review Manager 5.3 software and STATA 12.0.Results: Twenty-two randomized control trials (RCTs), including 2841 patients and 4268 knees, were eligible for the meta-analysis. The pooled results of subgroup analysis reveal that there was significant difference between HF-TKA and S-TKA in each subgroup in terms of postoperative ROM, with a higher degree of knee flexion for HF-TKA than S-TKA. However, no statistical difference was identified between HF-TKA and S-TKA in other clinical outcomes including various functional scores and complications.Conclusions: On the basis of this meta-analysis, we can recommended HF-TKA as an alternative choice to S-TKA for patients requiring higher knee flexion in their daily activities. [ABSTRACT FROM AUTHOR]

Mucus hypersecretion contributes to lung function impairment observed in COPD (chronic obstructive pulmonary disease), a tobacco smoking-related disease. A detailed mucus hypersecretion adverse outcome pathway (AOP) has been constructed from literature reviews, experimental and clinical data, mapping key events (KEs) across biological organisational hierarchy leading to an adverse outcome. AOPs can guide the development of biomarkers that are potentially predictive of diseases and support the assessment frameworks of nicotine products including electronic cigarettes. Here, we describe a method employing manual literature curation supported by a focused automated text mining approach to identify genes involved in 5 KEs contributing to decreased lung function observed in tobacco-related COPD. KE genesets were subsequently confirmed by unsupervised clustering against 3 different transcriptomic datasets including (1) in vitro acute cigarette smoke and e-cigarette aerosol exposure, (2) in vitro repeated incubation with IL-13, and (3) lung biopsies from COPD and healthy patients. The 5 KE genesets were demonstrated to be predictive of cigarette smoke exposure and mucus hypersecretion in vitro, and less conclusively predict the COPD status of lung biopsies. In conclusion, using a focused automated text mining and curation approach with experimental and clinical data supports the development of risk assessment strategies utilising AOPs. [ABSTRACT FROM AUTHOR]

In this work, we develop an improved shock-capturing and high-resolution Lagrangian–Eulerian method for hyperbolic systems and balance laws. This is a new method to deal with discontinuous flux and complicated source terms having concentrations for a wide range of applications science and engineering, namely, 1D shallow-water equations, sedimentation processes, Geophysical flows in 2D, N-Wave models, and Riccati-type problems with forcing terms. We also include numerical simulations of a 1D two-phase flow model in porous media, with gravity and a nontrivial singular δ -source term representing an injection point. Moreover, we present approximate solutions for 2D nonlinear systems (Compressible Euler Flows and Shallow-Water Equations) for distinct benchmark configurations available in the literature aiming to present convincing and robust numerical results. In addition, for the linear advection model in 1D and for a smooth solution of the nonlinear Burgers’ problem, second order approximations were obtained. We also present a high-resolution approximation of the nonlinear non-convex Buckley–Leverett problem. Based on the work of A. Harten, we derive a convergent Lagrangian–Eulerian scheme that is total variation diminishing and second-order accurate, away from local extrema and discontinuous data. Additionally, using a suitable Kružkov’s entropy definition, introduced by K. H. Karlsen and J. D. Towers, we can verify that our improved Lagrangian–Eulerian scheme converges to the unique entropy solution for conservation laws with a discontinuous space-time dependent flux. A key hallmark of our method is the dynamic tracking forward of the no-flow curves, which are locally conservative and preserve the natural setting of weak entropic solutions related to hyperbolic problems that are not reversible systems in general. In the end, we have a general procedure to construct a class of Lagrangian–Eulerian schemes to deal with hyperbolic problems with or without forcing terms. The proposed scheme is free of Riemann problem solutions and no adaptive space-time discretizations are needed. The numerical experiments verify the efficiency and accuracy of our new Lagrangian–Eulerian method. [ABSTRACT FROM AUTHOR]

The risks of selenium (Se) water contamination to human and aquatic life make it important to develop and apply efficient Se removal methods. Selenium photocatalytic reduction is an effective technique for this purpose, but it still suffers from limitations related to the photocatalyst recovery at the end of the process. In the present work, magnetic particles were coated with a titanium dioxide (TiO2) layer, using a sol–gel process, in order to obtain a magnetic recoverable Fe/TiO2 photocatalysts. The catalysts were prepared with different Fe concentrations and with or without thermal treatment, being then characterized by different techniques and applied in the Se photoreduction. Both calcined and non-calcined catalysts presented similar specific surface areas (19–29 m2 g− 1), but the latter showed better results in the photocatalytic tests (100% of Se removal in 15 min using the non-calcined 8% Fe photocatalyst). The photostability test performed using the best catalyst (non-calcined 8% Fe photocatalyst) indicated a decrease in the photoactivity from the second photocatalytic cycle onwards. Besides, the catalysts lost their magnetic properties after being calcined. [ABSTRACT FROM AUTHOR]

The abrasive waterjet (AWJ) cutting process has been widely used in the gemstone processing industry due to its versatility and accuracy characteristics. The influence of the parameters involved in the AWJ process has been investigated by many authors, and it can be seen that in each application different responses are reported. In agate processing via AWJ, the final quality of the piece depends on the properties of the initial damage region (IDR), such as width and depth. The present study has purpose to investigate the influence of the standoff distance, traverse speed, working pressure, and abrasive mass flow rate on the depth and width of the IDR when cutting agates through AWJ. A set of 80 samples were analyzed, and the measurement of the depth and width of the IDR was performed through three-dimensional scanning using X-ray computed microtomography (XCM). This technique allows assessing the IDR in an accurate and reliable way. The results showed that, within the investigated range of parameters, the width and depth of the IDR vary between 0.3 and 0.7 mm. Also, the IDR in the agate plates is strongly influenced by the standoff distance. [ABSTRACT FROM AUTHOR]

Agate plate cut by abrasive water jet (AWJ) process has several methods for assessing its quality, but there is no consensus among researchers about to which one is the most accurate and consistent method to use. The present work presents a new approach to classify the quality level of an agate surface cut by the abrasive water jet process, which is called comparative roughness criterion (Rcc). This method represents, in percentage terms, the thickness of the agate plate which is composed by the smooth zone (with good finish) in relation to the total thickness. An experimental study was conducted to validate this ratio, where the thickness of the smooth surface was defined by a surface roughness measured of the cut surface. A roughness ranging between 4 and 6 μm was found in the border between the smooth and rough region of the agate plates cut by AWJ. Therefore, the comparative roughness criterion (Rcc) based on roughness measurements proved to be a quantitative metric for evaluating the finish of cut agate plates under different AWJ processing conditions. [ABSTRACT FROM AUTHOR]

Purpose: Cystic fibrosis (CF) is a multisystem genetic disease caused by dysfunction of the epithelial anionic channel Cystic Fibrosis Transmembrane conductance Regulator (CFTR). Decreased mucociliary clearance because of thickened mucus is part of the pulmonary disease pathophysiology. It is controversial if the thickened airway surface liquid (ASL) is caused by the deficient chloride secretion and excessive sodium (through ENaC) and water hyperabsorption from the periciliar fluid or by the lack of bicarbonate secretion with relative acidification of the ASL. Correlations between the magnitude of in vivo chloride conductance with phenotypic characteristics and CF genotype can help to elucidate these mechanisms and direct to new treatments. Methods: Nasal potential difference was measured in 28 CF patients (age from 0.3 to 28 year) and correlated with pulmonary function, pancreatic phenotype, pulmonary colonization and genotype severity. Results: The CFTR-chloride conductance was better in older patients (r = 0.40; P = 0.03), in patients with better pulmonary function (r = 0.48; P = 0.01), and was associated with genotype severity. Higher chloride diffusion in the presence of a favorable chemical gradient was associated with Pseudomonas aeruginosa negativity (P < 0.05). More negative NPDmax was associated with pancreatic insufficiency (P < 0.01) as well with genotype severity, but not with the pulmonary function. Conclusions: The anion permeability through CFTR, mainly chloride, but bicarbonate as well, is the most critical factor in CF airway pathophysiology. Treatments primarily directed to correct CFTR function and/or airway acidity are clearly a priority. [ABSTRACT FROM AUTHOR]

Understanding the link between mode choice and travel satisfaction is essential for promoting sustainable travel by expanding utility theory to include also the eudaimonic value of travel. The study focuses on the hypothesis that more then it's functional value of arriving from A to B, mode choice creates travel experiences that answer high-order needs such as relatedness, autonomy and competence. This study enhances the framework for representing travel mode choice by incorporating the model of human needs as the missing link between mode choice and travel satisfaction. By developing and analysing a large-scale survey from the Greater Copenhagen Area in Denmark, this study empirically proves that commuting mode choice relates to travel satisfaction by answering functional, relatedness and growth needs. The Greater Copenhagen area represents a region where transit, bicycle and car each have large modal shares, hence enabling to validate the approach in a multi-modal environment. Higher bicycle satisfaction relates positively to cycling self-concepts and self-efficacy and negatively to car self-concepts. Greater car use satisfaction increases with car self-concepts and transit use difficulties, and decreases with functional difficulties in car use and better cycling self-efficacy. Higher transit satisfaction mainly relates to experiencing difficulties with other modes. These insights can be used when formulating transport policies and prioritising resources aimed at achieving sustainable mobility patterns. [ABSTRACT FROM AUTHOR]

The Einstein-de Haas effect was originally observed in a landmark experiment1 demonstrating that the angular momentum associated with aligned electron spins in a ferromagnet can be converted to mechanical angular momentum by reversing the direction of magnetization using an external magnetic field. A related problem concerns the timescale of this angular momentum transfer. Experiments have established that intense photoexcitation in several metallic ferromagnets leads to a drop in magnetization on a timescale shorter than 100 femtoseconds—a phenomenon called ultrafast demagnetization2-4. Although the microscopic mechanism for this process has been hotly debated, the key question of where the angular momentum goes on these femtosecond timescales remains unanswered. Here we use femtosecond time-resolved X-ray diffraction to show that most of the angular momentum lost from the spin system upon laser-induced demagnetization of ferromagnetic iron is transferred to the lattice on sub-picosecond timescales, launching a transverse strain wave that propagates from the surface into the bulk. By fitting a simple model of the X-ray data to simulations and optical data, we estimate that the angular momentum transfer occurs on a timescale of 200 femtoseconds and corresponds to 80 per cent of the angular momentum that is lost from the spin system. Our results show that interaction with the lattice has an essential role in the process of ultrafast demagnetization in this system. Femtosecond time-resolved X-ray diffraction reveals that in the ultrafast demagnitization of ferromagnetic iron, about 80% of the angular momentum lost from the spins is transferred to the lattice on a sub-picosecond timescale. [ABSTRACT FROM AUTHOR]

Assuming freight trip generation as the total number of freight vehicles arriving to retail establishments, for loading/unloading purposes and within a defined time period, we experiment and compare four alternative modeling methodologies to predict freight trip generation. The aim is to achieve better freight trip generation models, thus contributing to improving the chances of correctly dimension, for example, the parking infrastructure required to accommodate demand, or estimating the freight traffic impacts at micro level. Representing the state of the practice, the first two methodologies are based on cross-classification/category analysis. The third methodology uses a generalized linear model specification, a robust alternative to ordinary least squares linear regression. The fourth methodology consists in the exploration of a dependent variable simplification using an Ordinal Logit model. The main source of data is an Establishment-based Freight Survey, which collected data from 604 retail establishments in the city of Lisbon, Portugal. The selected independent variables were the establishments' industry category, number of employees and retail area. The analysis allowed for the conclusion that (a) variable contribution varies depending on the chosen modelling methodology, (b) there is little variability in the quality of predictions depending on the selected model, but a considerable improvement in correct predictions can be achieved by reducing the variability of the dependent variable, and (c) the proposed indicator framework is suitable to compare model predictions and might be adequately represented by subset of those applied. [ABSTRACT FROM AUTHOR]

Abrasive water jet (AWJ) machining is characterized by its versatility, i.e., it can be applied to a wide variety of materials. Currently, one important application is for manufacturing gem artifacts, especially agate, which is the largest gemological material produced in the state of Rio Grande do Sul. However, one of the main obstacles to its popularization is the cost associated with the process, due to the high abrasive consumption required for a good quality surface finish. In this sense, this research paper presents a study of the influence of the main process parameters (traverse speed and abrasive mass flow rate) on the surface finish of agates machined by AWJ. The experimental procedure used three different traverse speeds, four abrasive mass flow rate in two different thicknesses of agate's plates. Surface roughness and angle of striation marks were observed for different depths from the jet entrance surface. Results were analyzed using analysis of variance (ANOVA). Through the study, it was found that the machined surface finish varies according to the depth from the entrance surface of the abrasive jet. Also, it was concluded that the surface finish of the machined surface by AWJ (surface roughness and striation marks) of the agate's plates machined by AWJ exhibits similar results for both thicknesses tested. ANOVA showed that the traverse speed is more significant than abrasive mass flow rate for the material studied with respect to the surface finish. Thus, for a small material thickness, it is possible to use high traverse speed and low abrasive mass flow rate which makes the process more economical. [ABSTRACT FROM AUTHOR]

Autism can be defined as a heterogeneous behavioral syndrome in both genetic and diagnostic terms. This heterogeneity poses difficulties in conducting genetic studies on the topic. A candidate endophenotype of autism is theory of mind. The goal of this study was to evaluate the ability of theory of mind in parents of children with autism. We evaluated 90 participants: 30 parents of children with autism, 30 parents of children with Down syndrome and 30 parents of typically developing children. The instruments used were the Eyes Test, to assess decoding skills, and the Unexpected Outcomes Task, to measure deductive reasoning. The results do not indicate significant differences between groups in theory of mind decoding. However, they indicate the existence of deficits in the theory of mind reasoning. These deficits seem to be more pronounced in mothers of children with autism, compared to groups of mothers of children with Down syndrome and mothers of typically developing children. Further studies are needed to better clarify the relationship between theory of mind and autism. [ABSTRACT FROM AUTHOR]

Purpose: Femoral and tibial footprint coordinates have been well studied in double-bundle anterior cruciate ligament (ACL) reconstruction. However, in a single-bundle reconstruction approach, the central coordinate of femoral and tibial footprints have not been determined. The purpose of this study was to describe the central point locations of the ACL footprints visualized by three-dimensional computed tomography (3D CT) images and analysed by the quadrant method. Methods: Eight cadaveric knees were dissected, and the central points of ACL femoral and tibial footprints were marked and analysed using 3D CT images. Results: In the present study, the means (and standard deviation) of ACL femoral footprint dimensions were in the ventral-dorsal plane and in the cranial-caudal plane 9.4 ± 0.8 and 15.6 ± 0.9 mm, respectively. In the tibial side, the means of ACL footprint dimensions were in the anterior-posterior and in the medial-lateral 18.5 ± 1.9 and 15.5 ± 1.0 mm, respectively. In the tomographic analyses, the means of femoral central location coordinates in the ventral-dorsal ( y) and in the cranial-caudal ( x) axes were 35.3 ± 4.5 and 30.0 ± 1.6 %, respectively. The means of tibial central location coordinates were in the anterior-posterior ( y) and in the medial-lateral ( x) axes, respectively: 40.5 ± 5.3 and 50.2 ± 1.3 %, respectively. Conclusions: These computed tomographic coordinates might help future studies as a reference on ACL single-bundle anatomic reconstruction, with respect to the management of ACL revision surgery or in symptomatic patients after ACL reconstruction. Improvements in three-dimensional image acquisition could facilitate its intraoperative applicability in the coming years. [ABSTRACT FROM AUTHOR]

Musculoskeletal allografts are a valuable alternative to autograft tissue in orthopaedic surgeries. However, the effects of the allografts’ storage history on the collagen and subsequent allograft scaffold properties are unknown. In this study, we hypothesized that freezing and refrigeration of allografts for 1 week would alter the biologic performance and mechanical properties of the allograft collagen. Allograft collagen was characterized by SDS–PAGE migration pattern, amino acid profile and measured denaturation. Scaffolds made from allograft collagen were evaluated for fibroblast proliferation, platelet activation and scaffold retraction. Collagen gelation kinetics (elastic and inelastic moduli and the viscous-elastic transition point) were also evaluated. Fibroblast proliferation, platelet activation and scaffold retraction results showed only minor, though statistically significant, differences between the storage groups. In addition, there were no significant differences in rheological properties or collagen biochemistry. In conclusion, this study suggests that freezing or refrigeration for 1 week does not appear to have any detrimental effect on the mechanical properties and biologic performance of the collagen within allografts. [ABSTRACT FROM AUTHOR]

We are concerned with central differencing schemes for solving scalar hyperbolic conservation laws arising in the simulation of multiphase flows in heterogeneous porous media. We compare the Kurganov-Tadmor (KT) [3] semi-discrete central scheme with the Nessyahu-Tadmor (NT) [27] central scheme. The KT scheme uses more precise information about the local speeds of propagation together with integration over nonuniform control volumes, which contain the Riemann fans. These methods can accurately resolve sharp fronts in the fluid saturations without introducing spurious oscillations or excessive numerical diffusion. We first discuss the coupling of these methods with velocity fields approximated by mixed finite elements. Then, numerical simulations are presented for two-phase, two-dimensional flow problems in multi-scale heterogeneous petroleum reservoirs. We find the KT scheme to be considerably less diffusive, particularly in the presence of high permeability flow channels, which lead to strong restrictions on the time step selection; however, the KT scheme may produce incorrect boundary behavior. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate a 3D tumor segmentation method for fluorodeoxyglucose positron emission tomography (FDG-PET) in the context of noninvasive estimation of tumor metabolic length ( L m), as it correlates with surgical pathology and phantom results. Thirty-four patients (7 women, 27 men) with esophageal cancer were retrospectively evaluated. All patients underwent FDG-PET-computed tomography (CT) imaging following endoscopic ultrasound (EUS). Seventeen patients had esophagectomy after PET/CT, without prior neoadjuvant therapy. Tumor length was assessed by EUS ( L e, n = 31) and histopathology ( L p, n = 17). Images were evaluated quantitatively with a 3D threshold-based region-growing program (Medical Image Processing Analysis and Visualization). L m, total metabolic volume ( V m), maximum standardized uptake value (SUVmax), and average SUV (SUVa) over the entire tumor were obtained for several threshold values (mean activity in the liver plus 0-, 1-, 2-, 3-, and 4-SD of the activity in the liver). L m showed a good correlation with L p for all thresholds (best correlation for L m(2 -SD), r = 0.74, P < 0.001). A positive nonsignificant correlation was observed between L p and L e ( r = 0.30, P = 0.29). L m(2 -SD) correlated well with L e ( r = 0.71, P < 0.001). Good correlations were also observed between L m(2-SD) and V m(2-SD) ( r = 0.89, P < 0.001) and SUVa(2-SD) ( r = 0.38, P < 0.05). V m(2-SD) also had a significant correlation with L p ( r = 0.61, P < 0.05) and L e ( r = 0.57, P < 0.001). FDG-PET-derived tumor metabolic length of untreated esophageal carcinomas correlates well with surgical pathology results, and provides preliminary evidence that noninvasive delineation of the superior and inferior extent of viable tumor involvement might be feasible using computer-generated metabolic length measurements. [ABSTRACT FROM AUTHOR]

A method of extraction of proteins from cowpea for two-dimensional electrophoresis is presented. This method avoids loss of protein in the course of sample preparation and results in a fraction that yields reproducible 2-DE protein patterns. The efficiency of this method was demonstrated by comparison of the patterns of protein deposition in developing and mature cowpea seeds. It is also demonstrated that without further processing of the gel piece the proteins present in the spots can be directly digested with trypsin and the peptides subjected to mass spectrometry analysis for identification. [ABSTRACT FROM AUTHOR]

We show that a complete covariantization of the chiral constraint in the Floreanini-Jackiw necessitates an infinite number of auxiliary Wess-Zumino fields other-wise the covariantization is only partial and unable to remove the nonlocality in the chiral boson operator. We comment on recent works that claim to obtain covariantization through the use of Batalin-Fradkin-Tyutin method, that uses just one Wess-Zumino field. [ABSTRACT FROM AUTHOR]

In this work, we will analyze a noncommutative (NC) phase space version of the Friedmann–Robert–Walker cosmological models within the gravitational Hořava–Lifshitz theory. The matter content of the models is described by a perfect fluid and the constant curvature of the spatial sections may be positive, negative or zero. In order to obtain this theory, we will use the Faddeev–Jackiw symplectic formalism to introduce, naturally, phase space noncommutativity inside the equations that provide the dynamics of the theory. We will investigate, in details, the classical field equations of a particular version of the NC models. The equations will be modified, with respect to the commutative ones, by the introduction of a NC parameter. We will demonstrate that various NC models, with different types of matter and spatial constant curvatures, show several interesting and new results relative to the corresponding commutative ones. We will pay special attention to some cases, where the NC model predicts a scale factor accelerated expansion, which may describe the current state of our Universe. [ABSTRACT FROM AUTHOR]