On the particle paths and the stagnation points in small-amplitude deep-water waves

In order to obtain quite precise information about the shape of the particle paths below small-amplitude gravity waves travelling on irrotational deep water, analytic solutions of the nonlinear differential equation system describing the particle motion are provided. All these solutions are not closed curves. Some particle trajectories are peakon-like, others can be expressed with the aid of the Jacobi elliptic functions or with the aid of the hyperelliptic functions. Remarks on the stagnation points of the small-amplitude irrotational deep-water waves are also made.Comment: to appear in J. Math. Fluid Mech. arXiv admin note: text overlap with arXiv:1106.382

Why is management research irrelevant?

At least since 1980, there has been a practically continuous, but somewhat fragmented discussion on the relevance of management research. This discussion has addressed practically all fields of management; here, besides general management, operations management, project management and construction management are examined in more detail. Although many different proposals have been made to rectify the situation, no definitive resolution has been found. In this paper, it is argued that prior analyses have not reached the root causes of the irrelevance problem. By an analysis of the recent history of management research, the following novel findings are reached. First, the root cause of the irrelevance is argued to lie in the 1959 reports on American business education, written by Pierson and Gordon & Howell. Second, while the proposed direction in the 1959 reports was deficient in several ways, the rejection of production as an integral part of organizations and management has been perhaps the most damaging feature of those reports. Third, current research on management suffers from a variety of immediate causes for irrelevance, insufficiently recognized by the scholarly community. It is suggested that reaching the root causes for irrelevance will facilitate finding suitable cures

Dust in Supernovae and Supernova Remnants II: Processing and survival

Observations have recently shown that supernovae are efficient dust factories, as predicted for a long time by theoretical models. The rapid evolution of their stellar progenitors combined with their efficiency in precipitating refractory elements from the gas phase into dust grains make supernovae the major potential suppliers of dust in the early Universe, where more conventional sources like Asymptotic Giant Branch (AGB) stars did not have time to evolve. However, dust yields inferred from observations of young supernovae or derived from models do not reflect the net amount of supernova-condensed dust able to be expelled from the remnants and reach the interstellar medium. The cavity where the dust is formed and initially resides is crossed by the high velocity reverse shock which is generated by the pressure of the circumstellar material shocked by the expanding supernova blast wave. Depending on grain composition and initial size, processing by the reverse shock may lead to substantial dust erosion and even complete destruction. The goal of this review is to present the state of the art about processing and survival of dust inside supernova remnants, in terms of theoretical modelling and comparison to observations

G.: Topology based flow analysis and superposition effects

Summary. Using topology for feature analysis in flow fields faces several problems. First of all, not all features can be detected using topology based methods. Second, while in flow feature analysis the user is interested in a quantification of feature parameters like position, size, shape, radial velocity and other parameters of feature models, many of these parameters can not be determined using topology based methods alone. Additionally, in some applications it is advantageous to regard the vector field as a superposition of several, possibly simple, features. As topology based methods are quite sensitive to superposition effects, their precision and usability is limited in these cases. In this paper, topology based analysis and visualization of flow fields is estimated and compared to other feature based approaches demonstrating these problems.