A CutFEM method for two-phase flow problems

In this article, we present a cut finite element method for two-phase Navier-Stokes flows. The main feature of the method is the formulation of a unified continuous interior penalty stabilisation approach for, on the one hand, stabilising advection and the pressure-velocity coupling and, on the other hand, stabilising the cut region. The accuracy of the algorithm is enhanced by the development of extended fictitious domains to guarantee a well defined velocity from previous time steps in the current geometry. Finally, the robustness of the moving-interface algorithm is further improved by the introduction of a curvature smoothing technique that reduces spurious velocities. The algorithm is shown to perform remarkably well for low capillary number flows, and is a first step towards flexible and robust CutFEM algorithms for the simulation of microfluidic devices

Spectral/hp element methods for plane Newtonian extrudate swell

Spectral/hp element methods and an arbitrary Lagrangian-Eulerian (ALE) moving-boundary technique are used to investigate planar Newtonian extrudate swell. Newtonian extrudate swell arises when viscous liquids exit long die slits. The problem is characterised by a stress singularity at the end of the slit which is inherently difficult to capture and strongly influences the predicted swelling of the fluid. The impact of inertia (0 <Re < 100) and slip along the die wall on the free surface profile and the velocity and pressure values in the domain and around the singularity are investigated. The high order method is shown to provide high resolution of the steep pressure profile at the singularity. The swelling ratio and exit pressure loss are compared with existing results in the literature and the ability of high-order methods to capture these values using significantly fewer degrees of freedom is demonstrated

deal: A Package for Learning Bayesian Networks

deal is a software package for use with R. It includes several methods for analysing data using Bayesian networks with variables of discrete and/or continuous types but restricted to conditionally Gaussian networks. Construction of priors for network parameters is supported and their parameters can be learned from data using conjugate updating. The network score is used as a metric to learn the structure of the network and forms the basis of a heuristic search strategy. deal has an interface to Hugin.

Employment stability of entrants in newly founded firms: a matching approach using linked employer-employee data from Germany

Using a linked employer-employee dataset and taking the perspective of individuals rather than firms, this paper analyzes some effects of joining start-ups. We show that entrants in new firms differ from those joining incumbent firms, and we use a matching approach to compare a group of employees joining new firms in 1995/96 with a control group entering incumbent firms. Our results indicate that individuals' employment stability was higher in incumbent than in newly founded firms while their risk of becoming unemployed was lower. In particular in eastern Germany, joining firms that were older than six years was the best strategy. -- Diese Arbeit analysiert unter Verwendung eines verbundenen Arbeitgeber-Arbeitnehmer-Datensatzes einige Auswirkungen des Eintritts in Neugründungen, wobei die Sicht von Individuen statt von Firmen eingenommen wird. Wir zeigen, dass Personen, die in neue Firmen eintreten, sich von Eintreten-den in bestehende Firmen unterscheiden, und wir verwenden einen Matching-Ansatz, um eine Gruppe von Personen, die 1995/96 in Neugründungen eintrat, mit einer Kontrollgruppe von Eintretenden in bestehende Firmen zu vergleichen. Unsere Ergebnisse deuten darauf hin, dass die Beschäftigungsstabilität der eintre-tenden Personen in bestehenden Firmen höher als in Neugründungen ausfiel, während ihr Risiko arbeitslos zu werden geringer war. Insbesondere in den neuen Bundesländern bestand die beste Strategie darin, in Firmen einzutreten, die älter als sechs Jahre waren.employment,unemployment,newly founded firma,linked employer-employee data,Germany

How fast do newly founded firms mature? Empirical analyses on job quality in start-ups

Using a linked employer-employee data set for Germany, this paper analyzes labour fluctuation and wage setting in a cohort of newly founded and other establishments from 1997 to 2001. We show empirically that start-ups tend to have higher labour turnover rates, ceteris paribus. Moreover, bargaining coverage rates and wages in new firms are lower than in similar incumbent firms. Both the excess labour fluctuation and the wage differential are shown to decline and become insignificant over time as the newly founded firms mature. Our results imply that it takes a new firm only a few years to become an incumbent firm. -- Unter Verwendung eines kombinierten Firmen-Beschäftigten- Datensatzes für Deutschland analysiert dieser Beitrag die Arbeitskräftefluktuation und die Lohnsetzung in einer Kohorte von neu gegründeten und anderen Betrieben im Zeitraum von 1997 bis 2001. Wir zeigen empirisch, dass Neugründungen ceteris paribus tendenziell höhere Arbeitskräftefluktuationsraten aufweisen. Überdies liegen die Tarifbindungsquoten und die Löhne in Neugründungen unter denen in vergleichbaren bestehenden Betrieben. Es zeigt sich, dass mit der Reifung der Betriebe im Zeitablauf sowohl die erhöhte Arbeitskräftefluktuation als auch das Lohndifferenzial zurückgehen und schließlich insignifikant werden. Unsere Ergebnisse implizieren, dass es nur ein paar Jahre dauert, bis ein neues Unternehmen zu einem bestehenden Unternehmen wird.Labour turnover,wages,newly founded firms,linked employer-employee data,Germany

Do newly founded firms pay lower wages? : first evidence from Germany

"Using a linked employer-employee data set for Germany, this paper analyses wage setting in a cohort of newly founded and other establishments from 1997 to 2001. While theory provides alternative explanations for higher or lower wages in newly founded firms, we show empirically that start-ups tend to pay lower wages, ceteris paribus. On average, wages in newly founded establishments are 8 percent lower than in similar incumbent firms. This negative wage differential is substantially smaller in eastern than in western Germany. The wage differential is shown to decline over time as the newly founded firms become more mature." (Author's abstract, IAB-Doku) ((en))IAB-Linked-Employer-Employee-Datensatz, Unternehmensgründung, Unternehmensalter, Lohnstruktur, Lohnhöhe

Employment Stability of Entrants in Newly Founded Firms: A Matching Approach Using Linked Employer-Employee Data from Germany

Using a linked employer-employee dataset and taking the perspective of individuals rather than firms, this paper analyzes some effects of joining start-ups. We show that entrants in new firms differ from those joining incumbent firms, and we use a matching approach to compare a group of employees joining new firms in 1995/96 with a control group entering incumbent firms. Our results indicate that individuals’ employment stability was higher in incumbent than in newly founded firms while their risk of becoming unemployed was lower. In particular in eastern Germany, joining firms that were older than six years was the best strategy.linked employer-employee data, newly founded firms, unemployment, employment, Germany

How fast do newly founded firms mature? : empirical analyses on job quality in start-ups

"Using a linked employer-employee data set for Germany, this paper analyzes labour fluctuation and wage setting in a cohort of newly founded and other establishments from 1997 to 2001. We show empirically that start-ups tend to have higher labour turnover rates, ceteris paribus. Moreover, bargaining coverage rates and wages in new firms are lower than in similar incumbent firms. Both the excess labour fluctuation and the wage differential are shown to decline and become insignificant over time as the newly founded firms mature. Our results imply that it takes a new firm only a few years to become an incumbent firm." (Author's abstract, IAB-Doku) ((en))Unternehmensgründung, Unternehmensentwicklung