bluuebunny/crossref_metadata_2025_split huggingface dataset:
Condensing nozzle flows: Ludwieg tube experiments and numerical/ theoretical modelling
Authors: van Dongen M. E. H. , Lamanna G. , Prast B. 
Published: March 2011

AbstractThe present paper deals with homogeneously condensing flows of humid nitrogen in a Laval nozzle. The modelling of nonequilibrium condensation phenomena can be separated in two distinct processes: homogeneous nucleation and droplet growth. Our objective is to investigate the quality of a condensation model characterised by the following combination: the (corrected) Internally Consistent Classical Theory for the nucleation process and a generalised transitional growth model, with the droplet temperature calculated explicitly via the wet‐bulb equation. Our theoretical predictions have been then compared with our experimental results on droplet sizing showing a good agreement.
A New Law of State Model for Cavitation at Non‐Equilibrium
Authors: Vortmann C. , Schnerr G. H. 
Published: March 2011

AbstractFor practical reasons cavitating flow is often simulated using simple law of state models. These models are usually based on the assumption that the phase transition occurs if the pressures drops below the equilibrium vapor pressure. In order to improve the description of the cavitation process a new law of state model was developed that takes phase non‐equilibrium effects into account. By postulating the variation of the free enthalpy for the phase mixture a rate equation for the dryness fraction is derived. Concerning the calculation of two‐dimensional, unsteady cavitating flow the rate equation for dryness fraction is solved in combination with a modified Volume‐of‐Fluid algorithm.
Numerical Simulation of Cavitating Flow in Injector Nozzles
Authors: Yuan W. , Schnerr G. H. 
Published: March 2011

AbstractIn this study high‐velocity cavitating flows in injector nozzles are calculated using a modified Volume‐of‐Fluid method coupled with bubble dynamics. The calculations show that cavitation in injector nozzles may be unsteady and the interaction between the internal and external flow should be taken into account.
Numerical description of acoustic sources in airframe noise
Authors: Delfs J. , Grogger H. , Lauke Th. , Lummer M. , Yin J. 
Published: March 2011

AbstractThe origin of airframe noise in subsonic flows is mainly related to vorticity perturbations which i) interact with geometric inhomogeneities (egdes, steps, slots), ii) are subject to strong convective accelerations of the mean flow, iii) are strongly amplified in magnitude due to hydrodynamic instability of the mean flow. Therefore, apart from an appropriate modeling of the vorticity perturbations (e.g. causal or stochastic), a suitable Computational Aeroacoustics (CAA) method needs to describe accurately the conversion process from hydrodynamic to acoustic perturbations, i.e. the very noise generation. Aeronautics‐related examples of numerically simulated airframe noise phenomena are presented which were obtained using DLR's CAA‐code based on the high order spatial DRP scheme of Tam & Webb ]1[, the RK4 scheme in time and perfectly matched layers at the freefield boundaries Hu ]2[.
A model describing small elastic deformations and Korn's inequality with nonconstant coefficients
Authors: Neff Patrizio 
Published: March 2011

AbstractThis contribution is concerned with the formulation and mathematical investigation of a model for small elastic deformations which arises from multiplicative theories of elasto‐plasticity. In a natural way it leads to a linear elliptic system with nonconstant coefficients for the deformation u. In contrast to infinitesimal plasticity the model should he valid for both large plastic deformations Fp and large deformation gradients F. The arising linear partial differential system is proved to have unique solutions by means of a generalized Korn's inequality.
Compensated compactness for higher order differential relations
Authors: Raguz Andrija 
Published: March 2011

AbstractIn this paper we present two compensated compactness results which generalise well known results of Tartar and Murat. The first result generalises the basic compensated compactness theorem in quadratic case to differential relations of arbitrary order m. A particular result of this type has already been used in the homogenisation theory for elastic materials (Antonic and Balenovic, 1999). The other result treats the case where differential relations are of different order, and therefore cannot be reduced to the above form. Nevertheless, we obtain a result showing that we can pass to the limit in the product of two weakly converging sequences.
Index Concepts for General Systems of Partial Differential Equations
Authors: Seiler W. M. 
Published: March 2011

AbstractWe proposed recently some index concepts for general systems of partial differential equations ]12[ based on the so‐called formal theory. In this note we discuss their meaning in the context of semi‐discretisations. It is shown for some simple examples that the involution index of the original partial differential equations provides a lower bound for the index of the differential algebraic equations obtained by a semi‐discretisation.
Computer Aided Generation of Approximate DAE Systems for Symbolic Analog Circuit Design
Authors: Wichmann T. 
Published: March 2011

AbstractThe behavior of nonlinear analog circuits is described by a set of differential algebraic equations (DAE). We are developing simplification and approximation methods which can be applied to this DAE system in order to generate a reduced symbolic system, where a user given error bound is assured automatically. Either the reduced system can be analyzed further to achieve a better understanding of the circuit's behavior or it can be used as a behavioral model which can be solved numerically easier and faster. In the following we will focus on two aspects of the algorithm: simplification of subexpressions and monitoring of the index during simplification.
Reliability of the beam with variable cross‐section under stochastic excitation
Authors: Mazur‐Sniady K. , Sniady P. 
Published: March 2011

AbstractThe paper presents the problem of reliability of a beam with periodically variable geometry under stochastic excitation. The approach is based on concepts of the nonasymptotic tolerance averaged model ]3[. In this way we formulated the averaged equations of the structured beam which describe the length‐scale effect ]1,2[. Using these averaged equations we obtain the probabilistic characteristics of the beam with periodically variable geometry. We will solve the problem of reliability of this beam as the problem of the first crossing.
Reliability of Elastic‐Plastic Bar Systems Loaded Dynamically
Authors: Sieniawska R. , Wysocka A. , Sukowski S. 
Published: March 2011

AbstractAn approach for calculating the reliability and sensitivity of elastic‐plastic systems loaded dynamically is presented. The algorithm integrates the random nature of static and dynamic load with elastic‐plastic strains of the structure. For the dynamic calculations the COSMOS system has been used and for calculating the reliability index and sensitivities the STRUREL system has been applied. Some example results of a roof grid are shown.
Random Response of a System Due to Periodic Excitation with Gaussian and Non‐Gaussian Disturbances
Authors: Sniady P. , Sieniawska R. , Sukowski S. 
Published: March 2011

AbstractThe vibrations of a linear system due to periodic excitation with some Gaussian and non‐Gaussian disturbances are studied. The disturbances are modelled by the white noise and by compound Poisson stochastic processes. The Ito formula for the white noise process and the general Ito formula for the compound Poisson process are applied to get the equations for calculating the probabilistic moments of the system response.
Identifying a major locus that regulates spontaneous arthritis in IL-1ra-deficient mice and analysis of potential candidates
Authors: JIAO YAN , JIAO FENG , YAN JIAN , XIONG QING , SHRINER DANIEL , HASTY KAREN , STUART JOHN , GU WEIKUAN 
Published: March 2011

SummaryTo identify genetic loci that regulate spontaneous arthritis in interleukin-1 receptor antagonist (IL-1ra)-deficient mice, an F2 population was created from a cross between Balb/c IL-1ra-deficient mice and DBA/1 IL-1ra-deficient mice. Spontaneous arthritis in the F2 population was examined and recorded. Genotypes of those F2 mice were determined using microsatellite markers. Quantitative trail locus (QTL) analysis was conducted with R/qtlbim. Functions of genes within QTL chromosomal regions were evaluated using a bioinformatics tool, PGMapper, and microarray analysis. Potential candidate genes were further evaluated using GeneNetwork. A total of 137 microsatellite markers with an average of 12 cM spacing along the whole genome were used for determining the correlation of arthritis phenotypes with genotypes of 191 F2 progenies. By whole-genome mapping, we obtained QTLs on chromosomes 1 and 6 that were above the significance threshold for strong Bayesian evidence. The QTL on chromosome 1 had a peak near D1Mit55 and D1Mit425 at 82·6 cM. It may account for as much as 12% of the phenotypic variation in susceptibility to spontaneous arthritis. The QTL region contained 208 known transcripts. According to their functions, Mr1, Pla2g4a and Fasl are outstanding candidate genes. From microarray analysis, 11 genes were selected as favourable candidates based on their function and expression profiles. Three of those 11 genes, Prg4, Ptgs2 and Mr1, correlated with the IL-1ra pathway. Those genes were considered to be the best candidates.
Molecular cloning and characterization of a M17 leucine aminopeptidase of Cryptosporidium parvum
Authors: KANG J.-M. , JU H.-L. , SOHN W.-M. , NA B.-K. 
Published: March 2011

SUMMARYLeucine aminopeptidases (LAPs) are a group of metalloexopeptidases that catalyse the sequential removal of amino acids from the N-termini of polypeptides or proteins. They play an important role in regulating the balance between catabolism and anabolism in living cells. LAPs of apicomplexa parasitic protozoa have been intensively investigated due to their crucial roles in parasite biology as well as their potentials as drug targets. In this study, we identified an M17 leucine aminopeptidase of Cryptosporidium parvum (CpLAP) and characterized the biochemical properties of the recombinant protein. Multiple sequence alignment of the deduced amino acid sequence of CpLAP with those of other organisms revealed that typical amino acid residues essential for metal binding and active-site formation in M17 LAPs were well conserved in CpLAP. Recombinant CpLAP shared similar biochemical properties such as optimal pH, stability at neutral pHs, and metal-binding characteristics with other characterized LAPs. The enzyme showed a marked preference for Leu and its activity was effectively inhibited by bestatin. These results collectively suggest that CpLAP is a typical member of the M17 LAP family and may play an important role in free amino acid regulation in the parasite.
Beak condition drives abundance and grooming-mediated competitive asymmetry in a poultry ectoparasite community
Authors: CHEN BRIAN L. , HAITH KATHRYN L. , MULLENS BRADLEY A. 
Published: March 2011

SUMMARYObjective.Ornithonyssus sylviarum(northern fowl mite) andMenacanthus stramineus(chicken body louse) are key poultry pests currently controlled by exclusion or pesticide application. We studied how host beak condition affected their populations over time and how the lice and mites might interact on a host.Methods. Beak-trimmed or beak-intact white leghorn hens were infested initially with either mites or lice and subsequently challenged using the alternate ectoparasite species (reciprocal transfer), while other hens harboured only the initial ectoparasite species.Results. Beak-trimmed hens had far higher ectoparasite numbers relative to beak-intact hens, and the 2 ectoparasites showed evidence of grooming-mediated competitive asymmetry. On beak-trimmed hens, larger numbers of lice quickly nearly completely excluded mites in competition for enemy-free space (lower abdomen), while in the reciprocal transfer mites did not affect louse numbers on beak-trimmed hosts. The 2 ectoparasites co-existed on beak-intact hens, which were better able to defend the lower abdomen habitat by grooming.Conclusion. Lice are somewhat less damaging and much easier to control relative to mites, and might be used to eliminate mites in commercial, beak-trimmed flocks. Beak trimming impairs host grooming and contributes greatly to the high ectoparasite populations seen in commercial flocks. The study adds incentives for poultry breeders to develop more docile hen strains that can be held without beak trimming. This has advantages both to welfare advocates and producers who may no longer need to use insecticides for pest control or be concerned about worker exposure to pesticides.
Conformational dynamics of the molecular chaperone Hsp90
Authors: Krukenberg Kristin A. , Street Timothy O. , Lavery Laura A. , Agard David A. 
Published: March 2011

AbstractThe ubiquitous molecular chaperone Hsp90 makes up 1–2% of cytosolic proteins and is required for viability in eukaryotes. Hsp90 affects the folding and activation of a wide variety of substrate proteins including many involved in signaling and regulatory processes. Some of these substrates are implicated in cancer and other diseases, making Hsp90 an attractive drug target. Structural analyses have shown that Hsp90 is a highly dynamic and flexible molecule that can adopt a wide variety of structurally distinct states. One driving force for these rearrangements is the intrinsic ATPase activity of Hsp90, as seen with other chaperones. However, unlike other chaperones, studies have shown that the ATPase cycle of Hsp90 is not conformationally deterministic. That is, rather than dictating the conformational state, ATP binding and hydrolysis only shift the equilibria between a pre-existing set of conformational states. For bacterial, yeast and human Hsp90, there is a conserved three-state (apo–ATP–ADP) conformational cycle; however; the equilibria between states are species specific. In eukaryotes, cytosolic co-chaperones regulate thein vivodynamic behavior of Hsp90 by shifting conformational equilibria and affecting the kinetics of structural changes and ATP hydrolysis. In this review, we discuss the structural and biochemical studies leading to our current understanding of the conformational dynamics of Hsp90, as well as the roles that nucleotide, co-chaperones, post-translational modification and substrates play. This view of Hsp90's conformational dynamics was enabled by the use of multiple complementary structural methods including, crystallography, small-angle X-ray scattering (SAXS), electron microscopy, Förster resonance energy transfer (FRET) and NMR. Finally, we discuss the effects of Hsp90 inhibitors on conformation and the potential for developing small molecules that inhibit Hsp90 by disrupting the conformational dynamics.
Equidistribution of singular measures on nilmanifolds and skew products
Authors: POLO FABRIZIO 
Published: March 2011

AbstractWe prove that for a minimal rotationTon a two-step nilmanifold and any measureμ, the push-forwardTn⋆μofμunderTntends toward Haar measure if and only ifμprojects to Haar measure on the maximal torus factor. For an arbitrary nilmanifold we get the same result along a sequence of uniform density one. These results strengthen Parry’s result [Ergodic properties of affine transformations and flows on nilmanifolds.Amer. J. Math.91(1968), 757–771] that such systems are uniquely ergodic. Extending the work of Furstenberg [Strict ergodicity and transformations of the torus.Amer. J. Math.83(1961), 573–601], we get the same result for a large class of iterated skew products. Additionally we prove a multiplicative ergodic theorem for functions taking values in the upper unipotent group. Finally we characterize limits ofTn⋆μfor some skew product transformations with expansive fibers. All results are presented in terms of twisting and weak twisting, properties that strengthen unique ergodicity in a way analogous to that in which mixing and weak mixing strengthen ergodicity for measure-preserving systems.
A new approach on human–robot collaboration with humanoid robot RH-2
Authors: Monje C. A. , Pierro P. , Balaguer C. 
Published: March 2011

SUMMARYThis paper presents a novel control architecture for humanoid robot RH-2. The main objective is that a robot can perform different tasks in collaboration with humans in working environments. In order to achieve this goal, two control loops have to be defined. The outer loop, called collaborative control loop, is devoted to the generation of stable motion patterns for a robot, given a specific manipulation task. The inner loop, called posture stability control loop, acts to guarantee the stability of humanoid for different poses determined by motion patterns. A case study is presented in order to show the effectiveness of the proposed control architecture.
The songs of Johannes Decanus
Authors: Brewer Charles E. 
Published: March 2011

ABSTRACTIncluded in the collection of cantiones and Benedicamus tropes copied at the end of the Moosburger Graduale (München, Universitätsbibliothek, CIM 100 [olim 2o Cod. ms. 156], ff. 30v–250v) are five songs attributed to ‘Johannes Decanus’ (Johannes de Perchausen, †15.VIII.1362). In his preface to the song collection, Johannes describes three distinct repertoires (those ‘sung from antiquity’, ‘a few modern songs’ and ‘some of my own [songs]’) and through the examination of concordances it is possible to sort the songs into each of Johannes's categories. Against this background, three of Johannes's songs (Mos florentis venustatis, Flos campi profert lilium and Ad cultum tue laudis) demonstrate the consistent use of melodic rhyme, internal repetition of phrase units in both the verses and the refrains, and clear modal centring, found in most of the other Latin songs in the Moosburg collection. Two songs (Castis psallamus mentibus, and his Benedicamus trope, Florizet vox dulcisonans), however, represent a radical departure from these ‘norms’, through the unusual structuring of their melodies. These anomalous songs may reflect Johannes's desire to stretch the training and musicality of the young students of the Moosburg church with more modern melodic concepts.
A report on the encoding of melodic incipits in the CANTUS database with the music font ‘Volpiano’
Authors: Helsen Kate , Lacoste Debra 
Published: March 2011

ABSTRACTThe cantus project, begun more than twenty years ago, provides observations about medieval musical sources for the Office and the melodies they contain in a web-based, freely available format. The record for a single chant has always contained information about the feast to which it belongs, its placement within that feast, its text, its mode and its appearance. Owing to the recent introduction of the music font Volpiano into cantus records, information regarding pitch is now also available. Wherever feasible, records now include melodic incipits encoded as strings of letters and dashes which appear as note-heads on a five-line staff in Volpiano font. Melodic incipits increase the appeal of cantus as a research tool.
Leukemia inhibitory factor stimulates the transition of primordial to primary follicle and supports the goat primordial follicle viability in vitro
Authors: da Nóbrega Janduí Escarião , Gonçalves Paulo Bayard Dias , Chaves Roberta Nogueira , Magalhães Deborah de Melo , Rossetto Rafael , Lima-Verde Isabel Bezerra , Pereira Gabriel Ribas , Campello Cláudio Cabral , Figueiredo José Ricardo , de Oliveira João Francisco Coelho 
Published: March 2011

SummaryThe aim of this study was to evaluate the effect of leukemia inhibitory factor (LIF) on the activation and survival of preantral follicles cultured in vitro enclosed in ovarian fragments (in situ). Goat ovarian cortex was divided into fragments to be used in this study. One fragment was immediately fixed (fresh control – FC) and the remaining fragments were cultured in supplemented minimum essential medium (MEM) without (cultured control – CC) or with different concentrations of LIF (1, 10, 50, 100 or 200 ng/ml) for 1 or 7 days, at 39°C in air with 5% CO2. Fresh control, CC and treated ovarian fragments were processed for histological and fluorescence analysis. The percentage of histological normal preantral follicles cultured for 7 days with 1 ng/ml (49.3%), 10 ng/ml (58.6%) and 50 ng/ml (58%) of LIF was higher than in the CC (32.6%; p < 0.05). After 7 days of culture, the percentage of primordial follicles in situ cultured with LIF decreased and primary follicles increased in all LIF concentrations compared with FC and CC (p < 0.05). In conclusion, LIF induced primordial follicle activation and supported preantral follicle viability of goat ovarian tissues cultured for 7 days.
The number of 24 h dietary recalls using the US Department of Agriculture's automated multiple-pass method required to estimate nutrient intake in overweight and obese adults
Authors: Stote Kim S , Radecki Steven V , Moshfegh Alanna J , Ingwersen Linda A , Baer David J 
Published: March 2011

AbstractObjectiveTo determine the number of 24 h dietary recalls required to adequately estimate nutrient intake in overweight and obese adults using the US Department of Agriculture's (USDA) automated multiple-pass method (AMPM). In addition, the study quantified sources of variation in dietary intake, such as day of the week, season, sequence of diet interviews (training effect), diet interviewer, body weight and within- and between-subject variances in the intake of selected nutrients.DesignAdults having a BMI of ≥ 28 but <38 kg/m2 were included in the study. The USDA's AMPM was used to obtain 24 h dietary recalls every 10 d for 6 months. Dietary intake data were analysed to adequately estimate the number of 24 h recalls necessary to assess nutrient intake. Variance component estimates were made by using a mixed-model procedure.SettingThe greater Washington, DC, metropolitan area.SubjectsAdults (34 men and 39 women) aged 35–65 years.ResultsOverweight and obese adults completed fourteen 24 h dietary recalls. Utilizing within- and between-subject variances requires 5–10 and 12–15 d of 24 h dietary recalls in men and women, respectively, to estimate energy and macronutrient intakes in a 6-month period. Within- and between-subject variances were the major contributors to variance in nutrient intakes. Day of the week, season, sequence, diet interviewer and body weight had little impact on variance.ConclusionsThis information is valuable for researchers planning to conduct studies on free-living individuals that include the collection of dietary intake data.