bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grenzlagen gegabelter Verdichtungsstöße
Authors: Wecken Franz 
Published: May 2007

AbstractDie Gesamtheit der gasdynamisch möglichen stationären Stoßwellengabeln läßt sich geometrisch darstellen durch zwei Flächenstücke, die von je einem geschlossenen Linienzuge berandet werden. Es werden vier Typen von Grenzlagen, also insgesamt 8 Randkurven unterschieden, die an 8 Eckpunkten zusammenstoßen Berechnungs‐ bzw. Konstruktionsverfahren und numerische Werte für sämtliche Grenzlagen werden angegeben. Frühere Darstellungen von A. Weise, H. Eggink und W. Wuest werden ergänzt bzw. berichtigt.L'ensemble des bifurcations stationnaires d'ondes de choc étant possible selon les lois de la dynamique des gaz peut être représenté géométriquement par deux parties de surface dont chacune est limitée par une courbe close. On peut distinguer quatre types de positions limite, c'est‐à‐dire il y a huit courbes limite qui se rencontrent en huit coins. L'auteur publie des méthodes pour le calcul et la construction. De plus il donne des valeurs numériques pour toutes les positions limite. Les travaux antérieures par A. Weise, H. Eggink et W. Wuest traitant le même sujet sont complétés et corrigés.
Morphologisch homogene Funktionen und ihre Erzeugung durch statistische Superposition von Elementfunktionen I. I. Teil: Allgemeine Theorie
Authors: Giesekus Hanswalter 
Published: May 2007

AbstractDie Menge der morphologisch homogenen Funktionen (mhF) und die sie charakterisierenden Transformationen “Spektrum” und “Produktdurchschnitt” werden allgemein definiert. Dann wird aus dieser Menge diejenige Teilmenge behandelt, die man durch statistische Superposition quadratisch integrierbarer Elementfunktionen erzeugen kann, und zwar in der Weise, daß zuerst eine ganz spezielle Klasse sehr einfacher Funktionen betrachtet und diese dann sukzessive verallgemeinert wird: Spektrum und Produktdurchschnitt werden als Funktionen der entsprechenden Transformationen der Elementfunktionen dargestellt.
Fließgesetze normal‐zäher Stoffe im Rohr Ein Beitrag zur Rheologie
Authors: Prandtl L. , Vandrey Fr. 
Published: May 2007

AbstractUnter “Normalzähen Stoffen” werden hier Stoffe verstanden, deren Fließgesetz y˙ = f(τ) durch die Formel f(τ) = C Sin τ/A angenähert werden kann, mit y˙ = Deformationsgeschwindigkeit und τ = Schubspannung. Aufgabe der Abhandlung ist die Berechnung der Ahbängigkeit der Durchflußmenge eines solchen Stoffes in einem geraden Kreiszylindrischen Rohr vom Druckgefälle, ferner die Errechnung der Konstanten A und C vorgelegter Stoffe aus den Messungsergebnissen.
Der rotierende Tragflügel als Strahlungsproblem
Authors: Ernsthausen Wilhelm 
Published: May 2007

AbstractDie auf einen, im kompressiblen Gas rotierenden Tragflügel ausgeübten Kräfte entsprechen der Rückwirkung seines Schallfeldes. Sie lassen sich daher aus dem Energie‐Inhalt dieses Feldes bestimmen.
Spannungsfunktionen achsensymmetrischer Deformation in Zylinderkoordinaten
Authors: Timpe A. 
Published: May 2007

AbstractAnschließend an frühere Arbeiten wird das Problem der torsionsfreien, achsensymmetrischen Deformation von Umdrehungskörpern mittels einer einzigen Bipotentialfunktion behandelt. Die Methode wird auf Zylinderkoordinaten übertragen und auf verschiedene früher untersuchte typische Plattenprobleme zwecks Gewinnung eines einheitlichen Ausgangspunktes für allgemeinere Fälle angewendet.
Bemerkungen zur Stabilität eines physikalischen Pendels Zweite Mitteilung
Authors: Haacke Wolfhart 
Published: May 2007

AbstractIn dieser zweiten Mitteilung werden die Stabilisierungsphänomene des physikalischen Pendels bei beliebiger periodischer ebenen Bewegung des Aufhängepunktes untersucht, falls die Schwerkraftrichtung in dieser Bewegungsebene liegt. Bei Benutzung der Theorie der Mathieuschen Differentialgleichung, besonders der Struttschen Parameterkarte, kann systematisch und mit geringem Rechenaufwand entschieden werden, welche stabilen und labilen Lagen das Pendel einnehmen kann. Ausführlich werden die harmonische elliptische Oszillation und ihre Spezialfälle diskutiert.
Der Übergang vom ebenen Spannungszustand zum ebenen Formänderungszustand im breiten gebogenen Balken
Authors: Sonntag G. 
Published: May 2007

AbstractUnter Verwendung bekannter Lösungsansätze für Platten wird der Übergang vom ebenen Spannungszustand zum ebenen Formänderungszstand beim breiten gebogenen Balken allgemein streng angegeben und für einige Beispiele berechnet.
Über die konforme Abbildung gewisser rechtwinkliger Achtecke
Authors: Bundscherer N. 
Published: May 2007

AbstractDurch Überlagerung zweier mit Einschnitten versehener Rechtecke, deren Abbildung auf einfache Funktionen zurückgeführt werden kann, gelangt man zu gewissen rechtwinkligen Achtecken. Die Parameterwerte des Abbildungsintegrals lassen sich aus den Achtecksseiten berechnen. Spiegelung dieser (speziell auch ausgearteter) Achtecke liefert eine Anzahl abbildbarer Bereiche.
Der kanonische Formalismus in entarteten Fällen
Authors: Haag Rudolf 
Published: May 2007

AbstractFür Fälle, in denen die Gleichungen pα = ∂L/∂q̇α nicht nach den Geschwindigkeiten auflösbar sind, wird der kanonische Formalismus formuliert. Er führt auf Systeme mit überzähligen Variablen. Ihre Reduktion und die Frage nach dem Sinn von Poissonklammerrelationen in solchen Systemen wird im 2. Teil besprochen.
Fehlerabschätzung bei der ersten Randwertaufgabe bei elliptischen Differentialgleichungen
Authors: Collatz L. 
Published: May 2007

AbstractDer Satz vom Randmaximum für subharmonische Funktionen, der unter gewissen Voraussetzungen auch für allgemeinere lineare elliptische Differentialgleichungen gilt, dient bei 1. Randwertaufgabe zur Fehlerabschätzung für eine Näherungsfunktion, sowohl wenn diese wie z.B. beim Trefftzschen Verfahren nur die Differentialgleichung erfüllt, als auch, wenn sie wie z. B. beim Ritzschen Verfahren nur der Randbedingung genügt. Die Abschätzungen werden angewendet auf ein Verfahren, das auf eine Idee von R. v. Mises zurückgeht, bei welchem man Differentialgleichung und Randbedingungen simultan annähert.
Der Aufschlag von Rotationskörpern auf eine Wasseroberfläche. Richard v. Mises zum 70. Geburtstag gewidmet
Authors: Schmieden C. 
Published: May 2007

AbstractDer Aufschlag von Rotationskörpern auf eine freie Wasseroberfläche wird unter Voraussetzung schwacher Konturkrümmung untersucht und gezeigt, daß sich die Integralgleichung des Problems auf eine Abelsche Integralgleichung reduzieren läßt. Für einige Spezialfälle wird die Lösung in geschlossener Form angegeben und die auftretende Stoßkraft berechnet.
Durchbiegung von geschichteten Plattenkörpern mit leichter Füllung
Authors: Vodicka V. 
Published: May 2007

AbstractDurchbiegung von geschichteten Platten ist bisher nur für unendliche Platten berechnet worden. Im Falle endlicher Abmessungen betrachtete Prusakov das Problem ohne die einschränkenden Voraussetzungen, daß die innere Zentralschicht undeformiert bleibt und die Spannungen gleichförmig über die Höhe der äußeren Schichten verteilt sind, jedoch immer nur für den einfachsten Spezialfall eines aus 3 Schichten bestehenden Plattenkörpers.Dieser Aufsatz behält die Prusakovschen Verallgemeinerungen und fügt darüber hinaus noch andere hinzu.
The physical components of vectors and tensors
Authors: Truesdell C. 
Published: May 2007

AbstractPhysical components of vectors and tensors referred to general curvilinear co‐ordinates are defined and shown to represent quantities possessed of the natural physical dimensions of the field and capable of immediate physical interpretation. It is shown that scalar functions of second order tensors may be expressed directly in terms of the invariants of the physical components. For the case of orthogonal co‐ordinates, a general formula for the physical components of the covariant derivative of a tensor of any order is derived.
Die Spannungsfunktionen des dreidimensionalen Kontinuums und des elastischen Körpers
Authors: Schaefer Hermann 
Published: May 2007

AbstractDas Tensorfeld der Spannungen, dessen Divergenz durch die Gleichgewichtsbedingungen und dessen Rotation durch die Verträglichkeitsbedingungen vorgeschrieben sind, wird mit Hilfe eines Tensorpotentials, dem Tensor der Spannungsfunktionen, bestimmt. Für die kovarianten Rechnungen sind enge Analogien zur Einsteinschen Gravitationstheorie richtungsweisend. Im Sonderfall des isotropen elastischen, Körpers stößt man auf die Boussinesq‐Neuberschen Darstellungen der Spannungen und Verschiebungen durch Potentialfunktionen.
Prognostic Factors Affecting Survival and Recurrence of Patients with pT1 and pT2 Colorectal Cancer
Authors: Chok Kenneth S. H. , Law Wai Lun 
Published: May 2007

AbstractBackgroundData on the prognostic factors of survival and recurrence in patients with colorectal cancers confined to the bowel wall (T1 and T2) are limited. The aim of the present study was to determine factors that might predict the survival and recurrence of patients who had T1 and T2 colorectal cancers.Patients and MethodsAll patients with T1 or T2 colorectal cancers who underwent resection in the Department of Surgery, University of Hong Kong Medical Centre, from 1996 to 2004 were included. Analysis was made from the prospectively collected database. Predictive factors for lymph node metastasis and prognostic factors were analyzed.ResultsA total of 265 patients (144 men) with the median age of 71 years (range: 33–93 years) were included. Seventy‐two patients had T1 cancers (rectal cancer n = 44; colon cancer n = 28; p = 0.89) and 193 patients suffered from T2 cancer (rectal n = 120; colon cancer n = 73). The overall incidence of lymph node metastasis was 12.7% (5.6% for T1 cancer and 14.5% for T2 cancer; p = 0.021). The presence of lymphovascular permeation was the only independent factor associated with a higher incidence of lymph node metastasis on multivariate analysis (odds ratio: 1.48, 95% CI: 1.44–13.47, p = 0.009). There were no significant differences in disease‐free 5‐year survival (T1 = 84.6%; T2 = 81.1%) and 5‐year cancer‐specific survival in patients with T1 and T2 tumors (T1 = 90.2%; T2 = 90.6%). Patients with lymph node metastasis had a significantly shorter disease‐free 5‐year survival (p < 0.001) and 5‐year cancer‐specific survival (p = 0.002) when compared with those having a negative lymph node status. Cox proportional hazards model analysis showed that lymph node status was the only significant independent factor predicting cancer‐specific survival (hazard ratio: 3.52, 95% CI: 1.60–7.71, p = 0.002) and disease‐free survival (hazard ratio: 3.42, 95% CI: 1.75–6.69, p < 0.001).ConclusionsPresence of lymphovascular permeation would have a significant higher chance of lymph node metastasis. Positive lymph node status was predictive of poorer survival in patients with T1 or T2 colorectal cancers. For those cancers with positive lymphovascular permeation, radical surgery is recommended.
A NEW REFINEMENT OF YOUNG'S INEQUALITY
Authors: Alzer Horst , Koumandos Stamatis 
Published: May 2007

AbstractA classical theorem due to Young states that the cosine polynomial$$ C_n(x)=1+\sum_{k=1}^{n}\frac{\cos(kx)}{k} $$is positive for all $n\geq1$ and $x\in(0,\pi)$. We prove the following refinement. For all $n\geq2$ and $x\in[0,\pi]$ we have$$ \tfrac{1}{6}+c(\pi-x)^2\leq C_n(x), $$with the best possible constant factor$$ c=\min_{0\leq t\lt\pi}\frac{5+6\cos(t)+3\cos(2t)}{6(\pi-t)^2}=0.069\dots. $$
ON THE BLOW-UP OF THE NON-LOCAL THERMISTOR PROBLEM
Authors: Kavallaris N. I. , Nadzieja T. 
Published: May 2007

AbstractThe conditions under which the solution of the non-local thermistor problem\begin{gather*} u_t=\Delta u+\frac{\lambda f(u)}{(\int_{\varOmega}f(u)\,\mathrm{d}x)^{2}},\quad x\in\varOmega\subset\mathbb{R}^N,\ N\geq2,\ t>0, \\ \frac{\partial u(x,t)}{\partial\nu}+\beta(x)u(x,t)=0,\quad x\in\partial\varOmega,\ t>0, \\ u(x,0)=u_0(x),\quad x\in\varOmega, \end{gather*}blows up are investigated. We assume that $f(s)$ is a decreasing function and that it is integrable in $(0,\infty)$. Considering a suitable functional we prove that for all $\lambda\gt0$ the solution of the Neumann problem blows up in finite time. The same result is obtained for the Robin problem under the assumption that $\lambda$ is sufficiently large $(\lambda\gg 1)$. In the proof of existence of blow-up for the Dirichlet problem we use the subsolution technique. We are able to construct a blowing-up lower solution under the assumption that either $\lambda\gt\lambda^*$ or $0\lt\lambda\lt\lambda^*$, for some critical value $\lambda^*$, and that the initial condition is sufficiently large provided also that $f(s)$ satisfies the decay condition $\int_0^\infty[sf(s)-s^2f'(s)]\,\mathrm{d} s\lt\infty$.
SOLUTIONS OF SECOND-ORDER INTEGRO-DIFFERENTIAL EQUATIONS ON PERIODIC BESOV SPACES
Authors: Poblete Verónica 
Published: May 2007

AbstractMaximal regularity for an integro-differential equation with infinite delay on periodic vector-valued Besov spaces is studied. We use Fourier multipliers techniques to characterize periodic solutions solely in terms of spectral properties on the data. We study a resonance case obtaining a compatibility condition which is necessary and sufficient for the existence of periodic solutions.
Response of low-N pool maize population to nitrogen uptake and use efficiency after three cycles of full-sib recurrent selection
Authors: OMOIGUI L. O. , ALABI S. O. , KAMARA A. Y. 
Published: May 2007

SUMMARYIdentification of plant cultivars efficient for nitrogen (N) uptake and utilization may contribute to the improvement of crop yield potential in areas of low-N (LN) availability. Three cycles of full-sib recurrent selection were applied on a LN pool-yellow (LNP-Y) maize population to improve its level of tolerance to low soil N in the savannah ecosystem. The progress after three cycles of selection was evaluated for two years (2000 and 2001). The objectives of the study were to classify the cycles in relation to response to N levels under field conditions and to investigate the progress in selection for improved grain yield and other agronomic traits at two N levels, LN (30 kg N/ha) and high-N (HN, 90 kg N/ha). The experiment was conducted under field conditions at the LN screening site of the Institute for Agricultural Research, Samaru, in the northern Guinea savannah of Nigeria. The experimental design consisted of randomized complete blocks with three replications. The aboveground biomass and grain at harvest were analysed for total N content. The results indicated differences in plant population response to N levels. Mean grain yield ranged from 2·5 t/ha in cycle 1 to 2·7 t/ha in cycle 3 under LN and from 4·2 t/ha in cycle 1 to 4·3 t/ha in cycle 3 under HN. The observed gains were 4·8% per cycle under LN and 1·4% per cycle under HN. Nitrogen use efficiency (NUE) traits, viz. N uptake efficiency and N utilization efficiency were positively affected by selection. Gains for N utilization efficiency were 6·3% per cycle at LN and 9·1% per cycle at HN, while observed gains for NUE were 3·9% at LN and 1·4% per cycle at HN. However, N utilization efficiency was identified as the most important component of NUE for selecting cycles of selection in population development. Total N content and N utilization efficiency were significantly correlated with each other at LN, and had a significant, positive, direct effect on grain yield. Grain yield was positively correlated with N content and N utilization efficiency at both N levels. Also, a significant positive correlation was observed at LN between 300 kernel weight and N utilization efficiency. N utilization efficiency was correlated with ears/plant at HN and negatively correlated with anthesis-silking interval (ASI). The present study revealed that selection for improved productivity under LN stress conditions could be further enhanced by simultaneously selecting for high grain yield performance based on N utilization efficiency and on secondary traits, such as ears/plant, 300 kernel weight, and reduced ASI.
Molecular phylogeny of clade III nematodes reveals multiple origins of tissue parasitism
Authors: NADLER S. A. , CARRENO R. A. , MEJÍA-MADRID H. , ULLBERG J. , PAGAN C. , HOUSTON R. , HUGOT J.-P. 
Published: May 2007

SUMMARYMolecular phylogenetic analyses of 113 taxa representing Ascaridida, Rhigonematida, Spirurida and Oxyurida were used to infer a more comprehensive phylogenetic hypothesis for representatives of ‘clade III’. The posterior probability of multiple alignment sites was used to exclude or weight characters, yielding datasets that were analysed using maximum parsimony, likelihood, and Bayesian inference methods. Phylogenetic results were robust to differences among inference methods for most high-level taxonomic groups, but some clades were sensitive to treatments of characters reflecting differences in alignment ambiguity. Taxa representing Camallanoidea, Oxyurida, Physalopteroidea, Raphidascarididae, and Skrjabillanidae were monophyletic in all 9 analyses whereas Ascaridida, Ascarididae, Anisakidae, Cosmocercoidea, Habronematoidea, Heterocheilidae, Philometridae, Rhigonematida and Thelazioidea were never monophyletic. Some clades recovered in all trees such as Dracunculoidea and Spirurina included the vast majority of their sampled species, but were non-monophyletic due to the consistent behaviour of one or few ‘rogue’ taxa. Similarly, 102 of 103 clade III taxa were strongly supported as monophyletic, yet clade III was paraphyletic due to the grouping of Truttaedacnitis truttae with the outgroups. Mapping of host ‘habitat’ revealed that tissue-dwelling localization of nematode adults has evolved independently at least 3 times, and relationships among Spirurina and Camallanina often reflected tissue predilection rather than taxonomy.
Adaptation ofCryptosporidiumoocysts to different excystation conditions
Authors: WIDMER G. , KLEIN P. , BONILLA R. 
Published: May 2007

SUMMARYWithin the genusCryptosporidium2 lineages have evolved, one adapted to the acid environment of the stomach and abomasum, the other comprising parasites that multiply in the small intestine. We tested whether the release of sporozoites from oocysts, a process known as excystation, is triggered by conditions which mimic the site of infection. Specifically, we exposed oocysts from gastric and intestinalCryptosporidiumspecies to acid conditions or to a neutral solution of taurocholic acid, at 37°C. We found that oocysts from the gastric speciesC. murisandC.andersoniexcysted in both conditions, whereas the intestinal speciesC. parvumandC. hominisdid not respond to acid. When the effect of temperature alone was tested onC. murisandC. parvum, only oocysts from the former species excysted in significant numbers. Oocysts from intestinal species did not respond to temperature alone, nor to acidity. These observations are consistent with the need of gastric species to rapidly excyst and release the sporozoites upon ingestion, and indicate thatCryptosporidiumoocysts have evolved to maximize delivery of sporozoites to the region of the gastro-intestinal tract where the parasite multiplies.
Neuropsychological and behavioural disinhibition in adult ADHD compared to borderline personality disorder
Authors: LAMPE K. , KONRAD K. , KROENER S. , FAST K. , KUNERT H. J. , HERPERTZ S. C. 
Published: May 2007

ABSTRACTBackgroundAlthough attention-deficit/hyperactivity disorder (ADHD) is thought to be an inhibitory disorder, the question remains of how specific the inhibitory deficit is in adults and whether it distinguishes ADHD from borderline personality disorder (BPD), with which it shares several clinical features, particularly impulsiveness.MethodThe study assessed various motor and cognitive inhibitory functions (inhibition of prepotent, ongoing and interfering responses) in addition to working memory in adult ADHD patients with and without BPD, compared to subjects with BPD alone and controls. In addition, questionnaire data on various aspects of impulsiveness and anger regulation were assessed in all groups.ResultsADHD patients performed worse than BPD individuals and controls in two inhibitory tasks: the stop signal task and the conflict module of the Attentional Network Task (ANT). In addition, they exhibited longer reaction times (RTs) and higher intra-individual variance in nearly all attentional tasks. The co-morbid group exhibited poor performance on the stop signal task but not on the conflict task. The BPD group barely differed from controls in neuropsychological performance but overlapped with ADHD in some behavioural problems, although they were less severe on the whole.ConclusionsImpaired inhibition is a core feature in adults with ADHD. In addition, slow RTs and high intra-individual variance in performance may reflect deficits in the regulation of activation and effort in ADHD patients. ADHD and BPD share some symptoms of behavioural dysregulation without common cognitive deficits, at least in the attentional realm.
Confabulation in schizophrenia and its relationship to clinical and neuropsychological features of the disorder
Authors: LORENTE-ROVIRA E. , POMAROL-CLOTET E. , McCARTHY R. A. , BERRIOS G. E. , McKENNA P. J. 
Published: May 2007

ABSTRACTBackgroundA form of confabulation has been documented in schizophrenia and appears to be related to the symptom of thought disorder. It is unclear whether it is associated with the same pattern of neuropsychological deficits as confabulation in neurological patients.MethodThirty-four patients with chronic schizophrenia, including those with and without thought disorder, and 17 healthy controls were given a fable recall task to elicit confabulation. They were also examined on a range of executive, episodic and semantic memory tests.ResultsConfabulation was seen at a significantly higher rate in the schizophrenic patients than the controls, and predominated in those with thought disorder. Neuropsychologically, it was not a function of general intellectual impairment, and was not clearly related to episodic memory or executive impairment. However, there were indications of an association with semantic memory impairment.ConclusionsThe findings support the existence of a form of confabulation in schizophrenia that is related to thought disorder and has a different neuropsychological signature to the neurological form of the symptom.
Advances in genetic findings on attention deficit hyperactivity disorder
Authors: THAPAR ANITA , LANGLEY KATE , OWEN MICHAEL J. , O'DONOVAN MICHAEL C. 
Published: May 2007

ABSTRACTAttention deficit hyperactivity disorder (ADHD) is a common, childhood-onset neurodevelopmental disorder with adverse consequences during adult life. Family, twin and adoption studies show that genetic factors contribute to the aetiology of ADHD and that environmental factors also play a role. Family and twin studies have shown the importance of genetic influences on continuity in ADHD over time and in accounting for the co-occurrence of ADHD and conduct disorder problems. In meta-analyses of molecular genetic studies, the 48-bp variable number tandem repeat (VNTR) variant in the dopamine D4 gene and the CA(n) microsatellite marker in the D5 receptor gene have been found to be repeatedly associated with ADHD. Results from meta-analyses of the 480-bp VNTR in the dopamine transporter gene are mixed. Several genetic studies have also identified genetic variants that are related to specific clinical and developmental features of ADHD. In the next few years, a new generation of much larger-scale genetic studies should lead to the identification of further ADHD susceptibility genes. Such studies will also need to be integrated with other areas of neuroscience, clinical and epidemiological research to investigate how specific gene variants exert risk effects, interact with environmental factors and enable identification of the underlying causal mechanisms that lead to ADHD.