Formation of Polymorphic Cluster Phases for Purely Repulsive Soft Spheres

We present results from density functional theory and computer simulations that unambiguously predict the occurrence of first-order freezing transitions for a large class of ultrasoft model systems into cluster crystals. The clusters consist of fully overlapping particles and arise without the existence of attractive forces. The number of particles participating in a cluster scales linearly with density, therefore the crystals feature density-independent lattice constants. Clustering is accompanied by polymorphic bcc-fcc transitions, with fcc being the stable phase at high densities.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

Information Systems Offshoring—A Literature Review and Analysis

IS offshoring has become one of the most discussed phenomena in IS research and practice. Particularly due to its rapid evolvement, current research on IS offshoring lacks a consolidated view on existing results. The article at hand seeks to meet this need by systematically reviewing and analyzing prior academic literature on IS offshoring. Based on a review of top-ranked IS and management journals as well as IS conference proceedings, we compile an exhaustive bibliography of ninety-six publications solely focusing on IS offshoring from a (project) management perspective. To adequately address the immense diversity of these publications, a multi-perspective research framework consisting of three perspectives, namely, research focus, research approach, and reference theory, is introduced and forms the basis for our literature analysis. The analysis results confirm the appropriateness of our framework and reveal directions for future research along the framework perspectives: Most importantly, in an effort to increase the significance and the trustworthiness of their results, researchers should apply a more theory-driven approach and provide a better description of their research context. Moreover, future research needs to pay particular attention to the pre-implementation stages of an IS offshoring initiative as well as the special nature of nearshoring and captive offshoring. Across all project stages, researchers should not only concentrate on the client point of view but incorporate multiple points of view

Can dark energy viscosity be detected with the Euclid survey?

Recent work has demonstrated that it is important to constrain the dynamics of cosmological perturbations, in addition to the evolution of the background, if we want to distinguish among different models of the dark sector. Especially the anisotropic stress of the (possibly effective) dark energy fluid has been shown to be an important discriminator between modified gravity and dark energy models. In this paper we use approximate analytical solutions of the perturbation equations in the presence of viscosity to study how the anisotropic stress affects the weak lensing and galaxy power spectrum. We then forecast how sensitive the photometric and spectroscopic Euclid surveys will be to both the speed of sound and the viscosity of our effective dark energy fluid when using weak lensing tomography and the galaxy power spectrum. We find that Euclid alone can only constrain models with a very small speed of sound and viscosity, while it will need the help of other observables in order to give interesting constraints on models with a sound speed close to one. This conclusion is also supported by the expected Bayes factor between modelsD. S. acknowledges support from the JAEDoc program with Grant No. JAEDoc074 and the Spanish MICINN under Project No. AYA2009-13936-C06-06. D. S. also acknowledges financial support from the Madrid Regional Government (CAM) under the program HEPHACOS P-ESP-00346, Consolider-Ingenio 2010 PAU (CSD2007-00060), as well as the European Union Marie Curie Network ‘‘UniverseNet’’ under Contract No. MRTN-CT-2006-035863. E. M. was supported by the Spanish MICINNs Juan de la Cierva programme (Grant No. JCI-2010-08112), by CICYT through Project No. FPA-2009 09017, by the Community of Madrid through the project HEPHACOS (Grant No. S2009/ESP- 1473) under Grant No. P-ESP-00346 and by the European Union FP7 ITN INVISIBLES (Marie Curie Actions, PITNGA-2011-289442). M. K. acknowledges funding by the Swiss NS

Transport of Mars-Crossing Asteroids from the Quasi-Hilda Region

We employ set oriented methods in combination with graph partitioning algorithms to identify key dynamical regions in the Sun-Jupiter-particle three-body system. Transport rates from a region near the 3:2 Hilda resonance into the realm of orbits crossing Mars' orbit are computed. In contrast to common numerical approaches, our technique does not depend on single long term simulations of the underlying model. Thus, our statistical results are particularly reliable since they are not affected by a dynamical behavior which is almost nonergodic (i.e., dominated by strongly almost invariant sets)

Preliminary findings of cerebral responses on transcutaneous vagal nerve stimulation on experimental heat pain.

Transcutaneous vagal nerve stimulation (TVNS) is a promising complementary method of pain relief. However, the neural networks associated with its analgesic effects are still to be elucidated. Therefore, we conducted two functional magnetic resonance imaging (fMRI) sessions, in a randomized order, with twenty healthy subjects who were exposed to experimental heat pain stimulation applied to the right forearm using a Contact Heat-Evoked Potential Stimulator. While in one session TVNS was administered bilaterally to the concha auriculae with maximal, non-painful intensity, the stimulation device was switched off in the other session (placebo condition). Pain thresholds were measured before and after each session. Heat stimulation elicited fMRI activation in cerebral pain processing regions. Activation magnitude in the secondary somatosensory cortex, posterior insula, anterior cingulate and caudate nucleus was associated with heat stimulation without TVNS. During TVNS, this association was only seen for the right anterior insula. TVNS decreased fMRI signals in the anterior cingulate cortex in comparison with the placebo condition; however, there was no relevant pain reducing effect over the group as a whole. In contrast, TVNS compared to the placebo condition showed an increased activation in the primary motor cortex, contralateral to the site of heat stimulation, and in the right amygdala. In conclusion, in the protocol used here, TVNS specifically modulated the cerebral response to heat pain, without having a direct effect on pain thresholds