Boundary-induced coupling currents in a 1.3 m Rutherford-type cable due to a locally applied field change

In this paper the existence of so called Boundary-Induced Coupling Currents (BICCs) is experimentally demonstrated in a 1.3 m long Rutherford-type cable. These BICCs are induced by applying a field change locally onto the cable and can be represented by a non-uniform current distribution between the strands of the cable during and after the field sweep. In order to better understand the characteristic time, amplitude and characteristic length of these coupling currents and the parameters by which they are influenced, a special set-up has been built. With this set-up it is possible to scan the field induced by the BICCs along the full length of a Rutherford-type cable. Special attention is paid on the influence of the contact resistance between crossing strands on the characteristics of the BICCs, and results are presented where parts of the cable are soldered, simulating the joints of a coil

Cognitive enhancing effects of voluntary exercise, caloric restriction and environmental enrichment: A role for adult hippocampal neurogenesis and pattern separation?

Several behavioural interventions, such as physical exercise, dietary restriction, and enriched environments are associated with both improved cognition and increased adult hippocampal neurogenesis. Whether the learning and memory improvements associated with these interventions are causally dependent on the upregulated neurogenesis has not yet been conclusively determined. However, with the accumulating evidence of a role for adult-born hippocampal neurons in spatial pattern separation, it is possible that the improvements in learning and memory result, at least in part, from an improvement in pattern separation. The following review focuses on three major behavioural manipulations associated with cognitive enhancement: voluntary exercise, caloric restriction, and environmental enrichment (including learning), and how increased neurogenesis may contribute to the enhancement by improving pattern separation.The authors would like to acknowledge financial contribution from the following funding sources: the Innovative Medicine Initiative Joint Undertaking under grant agreement no. 115008, of which resources are composed of a European Federation of Pharmaceutical Industries and Associations in-kind contribution and financial contribution from the European Union's Seventh Framework Programme (FP7/2007–2013); The Wellcome Trust/Medical Research Council (089703/Z/09/Z) and the Biotechnology and Biological Sciences Research Council (grant BB/G019002/1). C.A.O. received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 603016. B.A.K. was supported by Gates Cambridge.This is the author accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S235215461500087X

Theoretical and experimental study of AC loss in HTS single pancake coils

The electromagnetic properties of a pancake coil in AC regime as a function of the number of turns is studied theoretically and experimentally. Specifically, the AC loss, the coil critical current and the voltage signal are discussed. The coils are made of Bi2Sr2Ca2Cu3O10/Ag (BiSCCO) tape, although the main qualitative results are also applicable to other kinds of superconducting tapes, such as coated conductors. The AC loss and the voltage signal are electrically measured using different pick up coils with the help of a transformer. One of them avoids dealing with the huge coil inductance. Besides, the critical current of the coils is experimentally determined by conventional DC measurements. Furthermore, the critical current, the AC loss and the voltage signal are simulated, showing a good agreement with the experiments. For all simulations, the field dependent critical current density inferred from DC measurements on a short tape sample is taken into account.Comment: 22 pages, 15 figures; contents extended (sections 3.2 and 4); one new figure (figure 5) and two figures replaced (figures 3 and 8); typos corrected; title change

The neurobiological characterization of distinct cognitive subtypes in early-phase schizophrenia-spectrum disorders

INTRODUCTION: Cognitive deficits are present in some, but not all patients with schizophrenia-spectrum disorders (SSD). We and others have demonstrated three cognitive clusters: cognitively intact patients, patients with deficits in a few domains and those with global cognitive deficits. This study aimed to identify cognitive subtypes of early-phase SSD with matched controls as a reference group, and evaluated cognitive subgroups regarding clinical and brain volumetric measures. METHODS: Eighty-six early-phase SSD patients were included. Hierarchical cluster analysis was conducted using global performance on the Brief Assessment of Cognition in Schizophrenia (BACS). Cognitive subgroups were subsequently related to clinical and brain volumetric measures (cortical, subcortical and cortical thickness) using ANCOVA. RESULTS: Three distinct cognitive clusters emerged: relative to controls we found one cluster of patients with preserved cognition (n = 25), one moderately impaired cluster (n = 38) and one severely impaired cluster (n = 23). Cognitive subgroups were characterized by differences in volume of the left postcentral gyrus, left middle caudal frontal gyrus and left insula, while differences in cortical thickness were predominantly found in fronto-parietal regions. No differences were demonstrated in subcortical brain volume. DISCUSSION: Current results replicate the existence of three distinct cognitive subgroups including one relatively large group with preserved cognitive function. Cognitive subgroups were characterized by differences in cortical regional brain volume and cortical thickness, suggesting associations with cortical, but not subcortical development and cognitive functioning such as attention, executive functions and speed of processing

Barium & related stars and their white-dwarf companions II. Main-sequence and subgiant stars

Barium (Ba) dwarfs and CH subgiants are the less-evolved analogues of Ba and CH giants. They are F- to G-type main-sequence stars polluted with heavy elements by a binary companion when the latter was on the Asymptotic Giant Branch (AGB). This companion is now a white dwarf that in most cases cannot be directly detected. We present a large systematic study of 60 objects classified as Ba dwarfs or CH subgiants. Combining radial-velocity measurements from HERMES and SALT high-resolution spectra with radial-velocity data from CORAVEL and CORALIE, we determine the orbital parameters of 27 systems. We also derive their masses by comparing their location in the Hertzsprung-Russell diagram with evolutionary models. We confirm that Ba dwarfs and CH subgiants are not at different evolutionary stages and have similar metallicities, despite their different names. Additionally, Ba giants appear significantly more massive than their main-sequence analogues. This is likely due to observational biases against the detection of hotter main-sequence post-mass-transfer objects. Combining our spectroscopic orbits with the Hipparcos astrometric data, we derive the orbital inclinations and the mass of the WD companion for four systems. Since this cannot be done for all systems in our sample yet (but should be with upcoming Gaia data releases), we also analyse the mass-function distribution of our binaries. We can model this distribution with very narrow mass distributions for the two components and random orbital orientation on the sky. Finally, based on BINSTAR evolutionary models, we suggest that the orbital evolution of low-mass Ba systems can be affected by a second phase of interaction along the Red Giant Branch of the Ba star, impacting on the eccentricities and periods of the giants.Comment: Accepted for publication in A&A on the 5th of April, 201

Q-koorts in Nederland: 2008 en verwachting voor 2009

In 2007 en 2008 deed zich in Nederland een epidemie van Q-koorts voor met resp. 196 en 906 bevestigde ziektegevallen. In dit artikel beschrijven de auteurs het verloop van de epidemie, het onderzoek, de maatregelen en de verwachting van het beloop in 2009. Q-koorts is, met name in het zuidoosten van Nederland, een nieuwe aandoening met belangrijke consequenties voor diagnostiek en therapi

Knee adduction moments are not increased in obese knee osteoarthritis patients during stair negotiation

Background: Negotiating stairs is an important activity of daily living that is also associated with large loads on the knee joint. In medial compartment knee osteoarthritis, the knee adduction moment during level walking is considered a marker for disease severity. It could be argued that the discriminative capability of this parameter is even better if tested in a strenuous stair negotiation task. Research question: What is the relation with knee osteoarthritis on the knee adduction moment during the stance phase of both stair ascent and descent in patients with and without obesity? Methods: This case control study included 22 lean controls, 16 lean knee osteoarthritis patients, and 14 obese knee osteoarthritis patients. All subjects ascended and descended a two-step staircase at a self-selected, comfortable speed. Three-dimensional motion analysis was performed to evaluate the knee adduction moment during stair negotiation. Results: Obese knee osteoarthritis patients show a prolonged stance time together with a more flattened knee adduction moment curve during stair ascent. Normalized knee adduction moment impulse, as well as the first and second peaks were not different between groups. During stair descent, a similar increase in stance time was found for both osteoarthritis groups. Significance: The absence of a significant effect of groups on the normalized knee adduction moment during stair negotiation may be explained by a lower ambulatory speed in the obese knee osteoarthritis group, that effectively lowers vertical ground reaction force. Decreasing ambulatory speed may be an effective strategy to lower knee adduction moment during stair negotiation