bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zur Stabilisierung von Gleichungen der ersten Variation durch Prozeßrechner
Authors: Herz B. 
Published: June 2007

AbstractEin lineares, zeitinvariantes, multivariables System werde als Gleichung der ersten Variation eines nicht explizit bekannten nichtlinearen Systems angesehen und durch eine lineare diskrete Regelung, etwa durch einen Prozeßrechner, stabilisiert. Unter für die Anwendungen hinreichend weiten Voraussetzungen hinsichtlich der bei der Linearisierung vernachlässigten Nichtlinearitäten wird gezeigt, daß diese Stabilisierung auch für das nichtlineare System exponentielle und totale Stabilität sicherstellt. Der von H. J. Stetter gegebene Begiff der totalen Stabilität bei diskreten Systemen wird dabei hier so modifiziert, daß vom Prozeßrechner gemachte zustandsabhängige Rundungsfehler mit erfaßt werden. Wegen der als unbekannt angenommenen, vernachlässigten Nichtlinearitäten ergeben sich zwangsläufig Fortsetzbarkeitsfragen, die im Zentrum der Betrachtung stehen.
Zur Verallgemeinerung zweistufiger Differenzenverfahren für nichtlineare hyperbolische Differentialgleichungssysteme
Authors: Stark W. , Wojcieszynski R. 
Published: June 2007

AbstractAusgehend von der von Lerat und Peyret entwickelten Klasse zweistufiger Differenzenverfahren zur Lösung hyperbolischer Differentialgleichungssysteme werden Berechnungsverfahren entwickelt, die aus dieser Klasse die problemorientiert‐optimalen Verfahren auswählen. Die Herleitung dieser Bestimmungsgleichungen erfolgt unter Ausnutzung der Theorie der einfachen Wellen und der Charakteristiken hyperbolischer Differentialgleichungssysteme.
Some Results Concerning Periodic Solutions of Plane Autonomous Differential Systems
Authors: Sandqvist A. , Andersen K. M. 
Published: June 2007

AbstractIn order to obtain results concerning the possible number of closed trajectories to the plane autonomous system ẋ = P(x, y), ẏ = Q(x, y) a related polar differential equation is considered. Some criteria are derived securing this equation to have at most one, respectively at most two 2π‐periodic solutions — thereby giving corresponding results for the number of closed trajectories to the autonomous system. As an illustration the results are applied to investigate a case of bifurcation in a specific example.
A Theoretical Treatment of Lifting Surface Theory of an Elliptic Wing
Authors: Kida T. 
Published: June 2007

AbstractThis paper is concerned with the exact theoretical treatment of the three‐dimensional lifting surface theory as treated in Krienes [9]. The method treated in this paper includes a new technique for the numerical approach, and the singularity of the lift distribution in the neighbourhood of the wing tips is examined in detail. To use the trigonometric series expressions of Lamé polynomial functions makes the numerical calculations easy and makes the accuracy improved. These expressions are available for the study of the singularity of the lift distribution near the wing tips.
Zur Stabilität ebener Schichtenströmungen gegenüber Störungen mit endlich großer Amplitude
Authors: Brechling J. 
Published: June 2007

AbstractDie Stabilität ebener Kanal‐ und Grenzschichtströmungen gegen periodische Störungen endlicher Amplitude wird numerisch als kombinierte Rand‐ und Eigenwertaufgabe untersucht. Es werden Amplituden der Störbewegung bis zur Größe turbulenter Schwankungsgeschwindigkeit betrachtet.
Periodic Stress Concentration Problems of Plane Orthotropic Elasticity
Authors: Krenk S. 
Published: June 2007

AbstractConvenient formulae are provided for the stress fields produced by isolated or periodically distributed forces and dislocations in plane orthotropic elasticity. Their application to the solution of boundary value problems and the influence of the elastic constants are discussed. Special attention is given to the problem of an elastic strip containing a periodic array of holes.
The Integration of Nonlinear Stochastic Systems with Applications to the Damage and Ambiguity Identification
Authors: Wedig W. 
Published: June 2007

AbstractThe paper investigates nonlinear stochastic systems with piecewise linear characteristics whose multi‐dimensional distribution densities are piecewise gaussian and therefore exactly calculable taking into account the necessary continuity and normalization conditions. Applying this approach to a cracked bending oscillator a spectral analysis is performed leading to the new phenomenon that the one degree of freedom system possesses two resonances the distance of which is a measure for the damage extension. In case of a vibrator with a piecewise progressive elasticity the spectral analysis is extended to amplitude frequency distributions in order to show the stochastic analogon to the ambiguity of the deterministic Duffing problem.
Einseitiges Knicken eines schweren Stabes
Authors: Vielsack P. 
Published: June 2007

AbstractEin schwerer gedrückter Stab auf starrer Unterlage kann neben der trivialen, geraden Lage auch nach oben gebogene Formen besitzen. Gefragt ist nach der kleinsten Druckkraft Für einen nichttrivialen Gleichgewichtszustand. Eine erste Näherung wird mit der Methode der singulären Störungsrechnung hergeleitet.
On the Economization of Stabilized Runge‐Kutta Methods with Applications to Parabolic Initial Value Problems
Authors: Sommeijer B. P. , van der Houwen P. J. 
Published: June 2007

AbstractA modification of Runge ‐ Kutta methods is analysed which leads for important classes of parabolic differential equations to a considerable reduction of the computational effort. The main characteristic of the modified methods is the replacement of the right hand side function of the differential equation by a “cheaper” function with roughly the same Jacobian matrix. Numerical experiments are reported and the results are compared with the results obtained by the unmodified Runge‐Kutta method and by an ADI method.
On the Incompleteness of the Number of Physical Parameters of a Free Streamline Potential Flow Problem
Authors: van der Zanden J. 
Published: June 2007

AbstractThe two‐dimensional free‐streamline solution of a plate rectangular in the flow of the jet from a nozzle is solved numerically. Earlier theoretical discussions of this problem mentioned only three physical parameters. However, this number must be equal to that of the independent geometrical parameters of the problem, which is four, otherwise the problem is not well posed. So a fourth parameter has been introduced. Numerical integration is preferred, although analytical integration is, in principle, possible. The determination of parameters and streamlines depends on the solution of nonlinear equations with inequality constraints.
Hydrodynamic Inlet Region Flow of Power‐Law Fluids in a Circular Tube
Authors: Gupta R. C. 
Published: June 2007

AbstractMomentum‐energy‐integral analysis for the laminar flow of power‐low fluids in the inlet region of a circular tube has been improved by incorporating Volkov's refinement of the Karman‐Pohlhausen method. Analytical expressions for the boundary layer development and the inlet region pressure‐distribution have been obtained. Results have been illustrated graphically and compared with some earlier analyses.
Nichtlineare Bewegungsgleichungen großer Mehrkörpersysteme
Authors: Schiehlen W. , Weidenhammer F. 
Published: June 2007

AbstractBei der dynamischen Untersuchung nichtlinearer mechanischer Systeme mit vielen Freiheitsgraden stellt bereits die Gewinnung der Bewegungsgleichungen ein wesentliches Problem dar. Es wird gezeigt, daß die Bewegungsgleichungen holonomer Mehrkörpersysteme durch die Anwendung des Jourdainschen Prinzips in einer einfacheren Form dargestellt werden können. Dies führt zu einem besseren mechanischen Verständnis symbolischer Gleichungen und zu kürzeren Rechenzeiten in numerischen Formalismen.
Dynamic Analysis of Cylindrical Shell under Hot Spot
Authors: Shirakawa K. 
Published: June 2007

AbstractThis paper is concerned with the dynamic analysis of a cylindrical shell subjected to a sudden change of temperature field by a hot spot at an initial state. Applying Dirac's delta function to the hot spot, the solutions are presented for the nonstationary equation of heat conduction for shell. The dynamic, thermoelastic cylindrical shell equation retaining all inertia terms are solved by employing Fourier and Laplace transforms. The solutions for a quasistatic problem enable us to discuss the singularities in thermal displacements and stresses. The importance of the dynamic effects in the practical applications is pointed out by showing some numerical examples. Shell equations employed in this study are those of Flügge and Donnell with the addition of thermal effects.
On a Direct Method of Integral Equations for Solving the Biharmonic Dirichlet Problem
Authors: Fuglede B. 
Published: June 2007

AbstractIn recent years an alternative method of integral equations has been used for numerical solution of the Dirichlet problem for the Laplace equation or the biharmonic equation in a bounded plane domain. This method is based simply on Green's third identity, and its main advantage is that is leads directly from the prescribed Dirichlet boundary data to the (physically relevant) Neumann data. It has been conjectured recently by S. Christiansen and P. Hougaard that, for certain values of the outer mapping radius of the domain, the integral equation(s) in question has (have) other solutions than that which stems from the solution to the Dirichlet problem. They proved this for a circular domain and gave numerical indications in another case. In the present paper we prove this and related conjectures in the case of a general domain with smooth boundary. We do not discuss the numerical aspects of the method in question.
Interaction of Elastic Waves with a Griffith Crack Situated in an Infinitely Long Strip
Authors: Srivastava K. N. , Gupta O. P. , Palaiya R. M. 
Published: June 2007

AbstractThe problem is the determination of the distribution of stress in the neighbourhood of a Griffith crack situated in an infinitely long elastic strip. The crack is opened by longitudinal elastic waves, incident normally on the crack. Fourier transforms are used to reduce the problem to a Fredholm integral equation of the second kind. Numerical solution of this equation is used for calculating the values of dynamical stress intensity factor at the edge of the crack. The results are illustrated graphically.
Young Women's Social and Occupational Development and Mental Health in the Aftermath of Child Sexual Abuse
Authors: Schilling Elizabeth A. , Aseltine Robert H. , Gore Susan 
Published: June 2007

AbstractWe examined social role functioning and depressive symptoms of young adults who were abused as children in data from a longitudinal community sample. Sexually abused women and men were more depressed during their senior year of high school, and this difference was more pronounced 2 years later. We then examined a mediational model to determine whether social functioning explained the course of depressive symptoms over this transitional period. Focusing only on young women, for whom the prevalence of abuse was much higher, results indicated that two‐thirds of the effect of abuse on depressive symptoms was explained by experiences and choices in the domains of work, education and intimate relationships. Having less supportive intimate relationships and lower rates of attendance at 4‐year colleges were particularly important. Findings reveal the key role played by early adult interpersonal and occupational development in perpetuating the mental health impact of childhood trauma.
Transcriptome analysis during the process ofin vitrodifferentiation ofLeishmania donovaniusing genomic microarrays
Authors: SRIVIDYA G. , DUNCAN R. , SHARMA P. , RAJU B. V. S. , NAKHASI H. L. , SALOTRA P. 
Published: June 2007

SUMMARYLeishmania donovanicauses visceral disease (kala-azar), a major health problem throughout the tropics with 500 000 new cases every year.Leishmaniadifferentiates from the promastigote to the amastigote form to establish infection in a mammalian host. To understand the process of differentiation, we assessed the global variation in gene expression in promastigotes, an intermediate stage of differentiation (PA24) and axenic amastigotes in culture using anL. donovanigenomic microarray with 4224 clones printed in triplicate. During an intermediate stage of differentiation 24 h after shifting the promastigotes into amastigotes (PA24), there were 41 (∼1%) clones with expression ⩾2·0-fold higher than promastigotes, whereas in terminally differentiated amastigotes there were 130 (∼3%) such clones. Of particular interest were certain genes that exhibited a transient increase or decrease in expression at the PA24 stage. Kinases showed a transient increase, and surface molecules, PSA and amino acid permease, were prominent clones among those showing a brief decrease at the PA24 stage. The microarray results have been validated using Northern blots or RT-PCR. In summary, our results provide important clues about the genes involved in the differentiation process ofL. donovanithat may contribute to virulence.
International environmental cooperation in northwest Russia: an assessment of performance
Authors: Tennberg Monica 
Published: June 2007

ABSTRACTThe effectiveness of international environmental cooperation is a theoretical and methodological challenge that has captured the interest of scholars and students of international relations in the recent years. This article is an evaluation of international environmental cooperation in northwest Russia by applying an approach developed in the Institutional Dimensions of Global Environmental Change (IDGEC) research programme of the International Human Dimension Programme (IHDP). The IDGEC approach emphasises the importance of complex diagnostics of institutional environmental arrangements in terms of performance. The approach relates to the effects of international environmental cooperation in terms of sustainability, efficiency, fairness, and robustness. The article focuses on Russian and Nordic experiences of international environmental cooperation, and the assessment of performance has been done by the participants themselves. According to the results of interviews and questionnaires, the cooperation is considered institutionally effective and robust in general. However, views about the environmental effects vary. Some problems exist that are related to sustainability and fairness, but the most critical issue is the lack of domestic environmental capacity in Russia.
Number and distribution of Adélie penguin (Pygoscelis adeliae) breeding sites in the Robinson Group of islands, Mac.Robertson Land coast, east Antarctica
Authors: Low Matthew , Meyer Lisa , Southwell Colin 
Published: June 2007

ABSTRACTIn November 2005, the first comprehensive survey for Adélie penguin (Pygoscelis adeliae) breeding sites in the Robinson Group of islands, situated 25 to 55 km east of Australia's Mawson station (67.602°S, 62.879°E) was conducted. Breeding Adélie penguins were found on 30 of the 149 islands, with the number of nests on each island ranging from fewer than 10 to several thousand. With the exception of those islands in the southeast, nesting Adélie penguins were found throughout the Robinson Group. In this paper, the spatial coordinates and presence/absence of breeding penguins for all 149 islands are reported so that researchers may interpret the results in relation to possible future survey work. All locations reported in this paper are in decimal degrees.
Globalisation and development in a post-nomadic hunter/gatherer Alaskan village: a follow-up assessment
Authors: Dinero Steven C. 
Published: June 2007

ABSTRACTUsing data collected in the Gwich'in Athabascan community of Vashraii K'oo/Arctic Village, an examination of how the village has continued to develop and evolve as a native space since its initial creation in 1908, is presented. Data collected using a household survey in 2006 is compared with data that was collected in a 1999 survey in order to address and measure such issues as: the village residents’ economic standing and subsistence activities; satisfaction with the planning and governance of the village; and residents’ overall attitudes toward the degree to which their village continues to function as an ‘ethnic space’. The previous conclusion (Dinero 2005) was that these villagers have responded relatively well to globalising forces, effectively bridging the native and white worlds in a manner which allows them to live in both, yet to retain a strong sense of their identity and cultural values despite residence in a settled, post-nomadic setting. While this remains the case, one cannot overlook in the present research the sense of loss of past lifeways that has resulted from the changes brought on by new technologies, despite any positive benefits deriving therefrom. Therefore, the conclusion of this paper is the suggestion that the development of this ‘hybridised’ Alaska native is still very much in process, as these people strive to adapt to the new challenges presented by their ever-changing environment.
UrbanDictionary.com
Authors: Damaso John , Cotter Colleen 
Published: June 2007

ABSTRACTIn traditional English lexicography, individual dictionary editors have had ultimate control over the selection, meaning, and illustration of words and extensive collaboration with contributors has been limited. However, Internet technologies that easily permit exchanges between a user and a database have allowed a new type of dictionary online: one that is built by the collaboration of contributing end-users, allowing users who are not trained lexicographers to engage in the actual making of dictionaries. We discuss here a popular online slang dictionary, UrbanDictionary.com (UD), to illustrate how traditional lexicographic principles are joined with Web-only communication technologies to provide a context for collaborative engagement and meaning-making, and to note the many characteristics and functions shared with traditional print dictionaries. Significantly, UD captures what most traditional English dictionaries fall short of: both recording ephemeral everyday spoken language and representing popular views of meaning. By relying on the users of language to select and define words for a dictionary, UD – which defines more than one million words – has in effect influenced both access to and formulation of the lexis.
Seroepidemiology of hepatitis A in voluntary blood donors from Pune, western India (2002 and 2004–2005)
Authors: GADGIL P. S. , FADNIS R. S. , JOSHI M. S. , RAO P. S. , CHITAMBAR S. D. 
Published: June 2007

SUMMARYRecently, a changing pattern of hepatitis A epidemiology has been reported in the Indian population indicating a rise in the rate of hepatitis A infection among adults. The study's objective was to assess anti-HAV prevalence in voluntary blood donors from middle and high socioeconomic strata. Serum samples collected from voluntary blood donors from Pune city and its suburbs in the years 2002 and 2004–2005 were tested for anti-HAV IgG antibodies. Serum samples collected during 2004–2005 were examined for anti-HAV IgM antibodies. Positive samples were tested for HAV-RNA. Agewise anti-HAV positivity was significantly low in adults aged 18–25 years (90·4%) compared to those aged >25 years (97·4%) (P<0·01). A decline in anti-HAV prevalence was significant in 2004–2005 compared to that in 2002 (96·5% vs. 92·1%) (P<0·01). Overall, in both adult age groups, the proportion of anti-HAV positivity was remarkably low in the high socioeconomic group (HSG) (88·96%) compared to that of the middle socioeconomic group (MSG) (95·86%) (P<0·01). Anti-HAV IgM positivity was not significant (~1%), however, presence of HAV-RNA in one of the samples indicated the possibility of horizontal transmission of HAV. Increase in seronegativity to HAV in HSG implicates a rise in the susceptible pool and indicates the need for vaccination against hepatitis A.
Semmelweis and the aetiology of puerperal sepsis 160 years on: an historical review
Authors: NOAKES T. D. , BORRESEN J. , HEW-BUTLER T. , LAMBERT M. I. , JORDAAN E. 
Published: June 2007

SUMMARYIt is generally accepted that Professor Ignaz Semmelweis was the first to identify the mode of transmission of puerperal sepsis. However no appropriate statistical analysis of Semmelweis's data supporting his theory has been reported. Mean annual percent maternal mortality rates for the Allgemeines Krankenhaus and Dublin Maternity Hospitals (1784–1858) were analysed. The introduction of pathological anatomy at the Allgemeines Krankenhaus in 1823 was associated with increased mortality. After 1840 maternal mortality was higher in Clinic 1 which was staffed by male obstetricians and medical students who, unlike the midwives in Clinic 2, attended autopsies. The introduction of chlorine washing of the male clinicians’ hands in Clinic 1 by Semmelweis in 1847 reduced mortality, whereas the cessation of handwashing after Semmelweis left Vienna in 1850 was associated with increased mortality. This statistical analysis supports Semmelweis's hypothesis that ‘the cadaveric particles adhering to the hand had … caused the preponderant mortality in the first Clinic’.
Population-based study of human papillomavirus infection and cervical neoplasia in Athens, Greece
Authors: KROUPIS C. , THOMOPOULOU G. , PAPATHOMAS T. G. , VOURLIDIS N. , LAZARIS A. C. 
Published: June 2007

SUMMARYThe aim of our study is to describe the prevalence of the different HPV types in women with pre-neoplastic lesions of the cervix in Greece. Cervical scrapes from 841 women were obtained for both cytological evaluation and analysis for the presence of HPV DNA. PCR was performed on specimens from these 841 women. The Pap test results were normal or showed benign cellular changes in 45·8% of the women, atypical squamous cells of undeterminated significance (ASCUS) in 23·2%, low-grade squamous intra-epithelial lesion (LSIL) in 27·9% and high-grade squamous intra-epithelial lesion (HSIL) in 3·1%. HPV DNA was demonstrated in 23·6% of cytologically normal women. We detected HPV in 60% of the total samples. Of these, HPV-16 was the most common HPV DNA detected. Interestingly, HPV-58 was inversely correlated with positive cytological findings. A clear pattern of decreasing prevalence of HPV with age was also observed. Our results indicate that HPV infections, especially those with HPV-16, represent a significant public health concern in Greece.
Cultivation of a novel cold-adapted nitrite oxidizing betaproteobacterium from the Siberian Arctic
Authors: Alawi Mashal , Lipski André , Sanders Tina , Eva-Maria-Pfeiffer  , Spieck Eva 
Published: June 2007

Abstract
Permafrost-affected soils of the Siberian Arctic were investigated with regard to identification of nitrite oxidizing bacteria active at low temperature. Analysis of the fatty acid profiles of enrichment cultures grown at 4°C, 10°C and 17°C revealed a pattern that was different from that of known nitrite oxidizers but was similar to fatty acid profiles of Betaproteobacteria. Electron microscopy of two enrichment cultures grown at 10°C showed prevalent cells with a conspicuous ultrastructure. Sequence analysis of the 16S rRNA genes allocated the organisms to a so far uncultivated cluster of the Betaproteobacteria, with Gallionella ferruginea as next related taxonomically described organism. The results demonstrate that a novel genus of chemolithoautotrophic nitrite oxidizing bacteria is present in polygonal tundra soils and can be enriched at low temperatures up to 17°C. Cloned sequences with high sequence similarities were previously reported from mesophilic habitats like activated sludge and therefore an involvement of this taxon in nitrite oxidation in nonarctic habitats is suggested. The presented culture will provide an opportunity to correlate nitrification with nonidentified environmental clones in moderate habitats and give insights into mechanisms of cold adaptation. We propose provisional classification of the novel nitrite oxidizing bacterium as ‘Candidatus Nitrotoga arctica’.