Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water

It has been suggested that high-density amorphous (HDA) ice is a structurally arrested form of high-density liquid (HDL) water, while low-density amorphous (LDA) ice is a structurally arrested form of low-density liquid (LDL) water. Recent experiments and simulations have been interpreted to support the possibility of a second "distinct" high-density structural state, named very high-density amorphous (VHDA) ice, questioning the LDL-HDL hypothesis. We test this interpretation using extensive computer simulations, and find that VHDA is a more stable form of HDA and that in fact VHDA should be considered as the amorphous ice of the quenched HDL.Comment: 5 pages, 4 fig

The Open Methods of Coordination as Amplifier for EU Soft Law

The final publication is available at Springer via http://dx.doi.org/[insert DOI

Optimal trap shape for a Bose gas with attractive interactions

Dilute Bose gas with attractive interactions is considered at zero temperature, when practically all atoms are in Bose-Einstein condensate. The problem is addressed aiming at answering the question: What is the optimal trap shape allowing for the condensation of the maximal number of atoms with negative scattering lengths? Simple and accurate analytical formulas are derived allowing for an easy analysis of the optimal trap shapes. These analytical formulas are the main result of the paper.Comment: Latex file, 21 page

In beweging! Over de ontwikkeling van de identiteit van een kennisorganisatie in een veranderende context

On the move! About organizational identity formation in a changing context How does the identity of an organization develop in a permanently changing environment on which it depends and with which it is intertwined through networks? This question forms the subject of a case study performed by the Netherlands Institute for Sport and Physical Activity (NISB). Tackling problems and attaining goals requires the exchange and combination of goods, services and expertise. To achieve that, organizations work together in networks. Social problems, however, tend to be complex because they involve different parties with different backgrounds and different interests. Moreover, constant changes in the environment constantly require a response from organizations to safeguard their position. Confronted with changes, organizations are faced with dilemmas. These dilemmas reveal value contrasts that organizations have to deal with and that lead them to constantly reconsider their identity. Dilemmas and decision-making have been selected as the starting point for data collection in the study, the results of which show that, in order to preserve its mission, the NISB is constantly adapting its identity to suit the environment. In other words, a robust working method and a stable mission constantly create a new interactive identity. In beweging! Over de ontwikkeling en handhaving van de identiteit van een kennisorganisatie in een veranderende context Hoe ontwikkelt de identiteit van een organisatie zich in een permanent veranderende omgeving waarmee zij via netwerken verweven is en waarvan zij afhankelijk is? Deze vraag is onderwerp van een casestudy, uitgevoerd bij het Nederlands Instituut voor Sport en Bewegen (NISB). Bij de aanpak van problemen en het realiseren van doelstellingen is uitwisseling en bundeling van goederen, diensten en expertise noodzakelijk. Daartoe werken organisaties samen in netwerken. Maatschappelijke problemen zijn dikwijls complex omdat verschillende partijen vanuit uiteenlopende achtergronden en belangen betrokken zijn. Daar komt bij dat voortdurende veranderingen in de omgeving steeds vragen om een reactie van organisaties, dit met het oog op het behoud van haar positie. In de confrontatie met veranderingen stuiten organisaties op dilemma’s. Deze dilemma’s maken waardetegenstellingen zichtbaar, waar organisaties niet omheen kunnen en die vervolgens leiden tot een vrijwel permanente heroverweging van de identiteit van de organisatie. Dilemma’s en besluitvorming zijn gekozen als aangrijpingspunt voor de dataverzameling in het onderzoek. De resultaten laten zien hoe NISB, met behoud van haar missie, voortdurend haar identiteit aanpast aan haar omgeving. Met andere woorden, er is steeds sprake van interactieve identiteitsvorming die mogelijk gemaakt wordt door een robuuste werkwijze en een stabiele missi

Automatic IVUS segmentation of atherosclerotic plaque with Stop & Go snake

Since the upturn of intravascular ultrasound (IVUS)as an imaging technique for the coronary artery system, much research has been done to simplify the complicated analysis of the resulting images. In this study, an attempt to develop an automatic tissue characterization algorithm for IVUS images was done. We concentrated on the segmentation of calcium and soft plaque, because these structures predict the extension and the vulnerability of the atherosclerotic disease, respectively. The first step in the procedure was the extraction of texture features like local binary patterns, co-occurrence matrices and Gabor filter banks. After dimensionality reduction, the resulting feature space was used for classification, constructing a likelihood map to represent different coronary plaques. The information in this map was organized using a recently developed geodesic snake formulation,the so-called Stop & Go snake. The novelty of our study lies in this last step, as it was the first time to apply the Stop & Go snake to segment IVUS images

Spin superfluidity and spin-orbit gauge symmetry fixing

The Hamiltonian describing 2D electron gas, in a spin-orbit active medium, can be cast into a consistent non-Abelian gauge field theory leading to a proper definition of the spin current. The generally advocated gauge symmetric version of the theory results in current densities that are gauge covariant, a fact that poses severe concerns on their physical nature. We show that in fact the problem demands gauge fixing, leaving no room to ambiguity in the definition of physical spin currents. Gauge fixing also allows for polarized edge excitations not present in the gauge symmetric case. The scenario here is analogous to that of superconductivity gauge theory. We develop a variational formulation that accounts for the constraints between U(1) physical fields and SU(2) gauge fields and show that gauge fixing renders a physical matter and radiation currents and derive the particular consequences for the Rashba SO interaction.Comment: to appear in EP