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We establish the existence of solitary wave solutions with exponential decay at infinity for a nonlinear dispersive partial differential equation. As a by-product, the existence of smooth solitary waves for the Camassa-Holm equation, modeling water waves and waves in elastic rods, is obtained.
The aim of this study is to demonstrate how the cultural functions of a sacred motif have changed over the years by means of intermedial transformation. The object of study is an ekphrastic poem, "Theotokos", by the Swedish poet Ingemar Leckius. A couple of medieval Orthodox icon paintings - The Vladimir Madonna and The Virgin of the Sign - have served as sources of inspiration for the poet. A myt
The inverse spectral problem for the Laplace operator on a finite metric graph is investigated. It is shown that this problem has a unique solution for graphs with rationally independent edges and without vertices having valence 2. To prove the result, a trace formula connecting the spectrum of the Laplace operator with the set of periodic orbits for the metric graph is established.
According to the principle of least action, the spatially periodic motions of one-dimensional mechanical systems with no external forces are described in the Lagrangian formalism by geodesics on a manifold-configuration space, the group D of smooth orientation-preserving diffeomorphisms of the circle. The periodic inviscid Burgers equation is the geodesic equation on D with the L-2 right-invariant
In a previous contribution (Stockmann H J 2002 J. Phys. A: Math. Gen. 35 5165), the density of states was calculated for a billiard with randomly distributed delta-like scatterers, doubly averaged over the positions of the impurities and the billiard shape. This result is now extended to the k-point correlation function. Using supersymmetric methods, we show that the correlations in the bulk are a
Studies of apparently homogeneous cell populations and single cells often give highly divergent results. Cells exhibit varying responsiveness to stimuli and gene expression and they are in many aspects stochastic and unpredictable. We have developed a method to measure gene expression quantitatively in individual cells with real-time RT-PCR. mRNA for hormones, ion channels and enzymes in pancreat
One out of ten cases of acute pancreatitis develops into severe acute pancreatitis which is a life threatening disorder with a high mortality rate. The other nine cases are self limiting and need very little therapy. The specificity of good clinical judgement on admission, concerning the prognosis of the attack, is high (high specificity) but misses a lot of severe cases (low sensitivity). The pre
Force-velocity (F-V) relationships were determined for single frog muscle fibres during the rise of tetanic contraction. F-V curves obtained using isotonic shortening early in a tetanic contraction were different from those obtained at equivalent times with isovelocity shortening, apparently because changing activation early in the contraction leads, in isovelocity experiments, to changing force a
To evaluate the effects of dietary phospholipids on plasma lipoproteins in the postprandial phase six normolipidemic men were fed alternatively a test meal rich in phosphatidylcholine and a control meal low in phosphatidylcholine. Plasma very low-density lipoproteins, low-density lipoproteins, and high-density lipoproteins were isolated at 2, 4 and 6 h after the meals. The changes in lipoprotein c
The purpose of this paper is to discuss the conceptualisation of bibliometric analyses in terms of the levels on which they are performed, adding contextual factors to the dimension where the size of the unit being analysed is considered. Based on empirical investigations of resource allocation systems and research evaluation practices, as well as the previous literature conceptualising bibliometr
During spring and autumn a special thermohydrodynamic phenomenon, called a thermal bar, can be observed in dimictic lakes. [A dimictic lake is a lake where a complete turnover of the water occurs twice a year (in spring and autumn).] The thermal bar is a zone of mixing that separates waters with temperatures above and below 4° C. Its practical importance is due to the possibility that it might iso
The present article is a study of the surface temperature distribution and its evolution during spring in Lake Ladoga, using NOAA-AVHRR Channel 4/Channel 5 (CH4/CH5) data, with special focus on a thermohydrodynamic phenomenon, called thermal bar. The split-window technique, where both constant and atmospheric-mass-dependent retrieval coefficients are tested, is used for calculating the atmospheric
Lindström & Alerstam (1992Am. Nat.140,477–491) presented a model that predicts optimal departure fuel loads as a function of the rate of fuel deposition in time-minimizing migrants. The basis of the model is that the coverable distance per unit of fuel deposited, diminishes with increasing fuel load. This is an effect of the increasing flight costs associated with increasing body mass. Lindstr
Using a highly comprehensive new data set on Swedish researchers, we investigate the effects of inter-university mobility on researcher productivity. Our study suggests substantial gains from mobility on scientific output. The empirical analysis addresses selection using inverse probability treatment censoring weights. We find that mobility induces a long-lasting increase in a researcher's publica
Immunologically insulin resistant (IIR) type I diabetic patients possess significantly elevated levels of anti-insulin serum autoantibodies. We investigated whether altered insulin processing by B lymphocytes contributes to this form of insulin resistance. A comparison was made of the 125I-labelled human insulin (HI) peptides processed by Epstein-Barr virus (EBV)-transformed B lymphocytes derived
