Splitting of the pi - rho spectrum in a renormalized light-cone QCD-inspired model

We show that the splitting between the light pseudo-scalar and vector meson states is due to the strong short-range attraction in the ^1S_0 sector which makes the pion and the kaon light particles. We use a light-cone QCD-inspired model of the mass squared operator with harmonic confinement and a Dirac-delta interaction. We apply a renormalization method to define the model, in which the pseudo-scalar ground state mass fixes the renormalized strength of the Dirac-delta interaction.Comment: 9 pages, 2 figures, revtex, accepted by Phys. Rev. D; Corrected typo

Conformation of a Polyelectrolyte Complexed to a Like-Charged Colloid

We report results from a molecular dynamics (MD) simulation on the conformations of a long flexible polyelectrolyte complexed to a charged sphere, \textit{both negatively charged}, in the presence of neutralizing counterions in the strong Coulomb coupling regime. The structure of this complex is very sensitive to the charge density of the polyelectrolyte. For a fully charged polyelectrolyte the polymer forms a dense two-dimensional "disk", whereas for a partially charged polyelectrolyte the monomers are spread over the colloidal surface. A mechanism involving the \textit{overcharging} of the polyelectrolyte by counterions is proposed to explain the observed conformations.Comment: 4 pages, 4 figures (6 EPS files

Dynamical ionization ignition of clusters in intense and short laser pulses

The electron dynamics of rare gas clusters in laser fields is investigated quantum mechanically by means of time-dependent density functional theory. The mechanism of early inner and outer ionization is revealed. The formation of an electron wave packet inside the cluster shortly after the first removal of a small amount of electron density is observed. By collisions with the cluster boundary the wave packet oscillation is driven into resonance with the laser field, hence leading to higher absorption of laser energy. Inner ionization is increased because the electric field of the bouncing electron wave packet adds up constructively to the laser field. The fastest electrons in the wave packet escape from the cluster as a whole so that outer ionization is increased as well.Comment: 8 pages, revtex4, PDF-file with high resolution figures is available from http://mitarbeiter.mbi-berlin.de/bauer/publist.html, publication no. 24. Accepted for publication in Phys. Rev.

Serum vitamin D levels are associated with structural and functional properties of the carotid artery in older men and women

Background and aims: This cross-sectional study aimed to assess the relationship between serum vitamin D levels and carotid and brachial artery distensibility in patients older than 55 years, referred to the outpatient clinic of the department of internal medicine and geriatric medicine of the Erasmus Medical Center, in Rotterdam. Methods and results: From April to July 2006 we consecutively enrolled 49 elder patients (21 men and 28 women, mean age 78 ± 8 years) without a cardiovascular event within 6 weeks before the visit. Carotid and brachial artery distensibility coefficients and serum 25(OH)D levels (mean 50 ± 28.8 nmol/L) were assessed. Multivariate analysis (with linear regression model) was performed to investigate the relation between these parameters: carotid artery distensibility coefficient was associated with serum 25(OH)D levels (β = 0.112; 95% CI 0.053 0.172; p = 0.001). Moreover, a negative association was also observed between carotid artery distensibility coefficient and mean arterial pressure (β = −0.279; 95% CI, −0.339 −0.159; p = 0.0001). On the contrary, brachial artery distensibility has shown no association with 25(OH)D levels, being negatively linked to LDL-cholesterol levels and heart rate. An association was also observed between serum 25(OH)D level and carotid artery intima–media thickness. Conclusion: Our results revealed that serum 25(OH)D levels of older men and women were associated with both structural and functional properties of the carotid artery. No association was found with the brachial artery distensibility

How spiking neurons give rise to a temporal-feature map

A temporal-feature map is a topographic neuronal representation of temporal attributes of phenomena or objects that occur in the outside world. We explain the evolution of such maps by means of a spike-based Hebbian learning rule in conjunction with a presynaptically unspecific contribution in that, if a synapse changes, then all other synapses connected to the same axon change by a small fraction as well. The learning equation is solved for the case of an array of Poisson neurons. We discuss the evolution of a temporal-feature map and the synchronization of the single cells’ synaptic structures, in dependence upon the strength of presynaptic unspecific learning. We also give an upper bound for the magnitude of the presynaptic interaction by estimating its impact on the noise level of synaptic growth. Finally, we compare the results with those obtained from a learning equation for nonlinear neurons and show that synaptic structure formation may profit from the nonlinearity

Quasi-coherent fluctuations limiting the pedestal growth on Alcator C-Mod: experiment and modelling

Performance predictions for future fusion devices rely on an accurate model of the pedestal structure. The candidate for predictive pedestal structure is EPED, and it is imperative to test the underlying hypotheses to further gain confidence for ITER projections. Here, we present experimental work testing one of the EPED hypotheses, namely the existence of a soft limit set by microinstabilities such as the kinetic ballooning mode. This work extends recent work on Alactor C-Mod (Diallo et al 2014 Phys. Rev. Lett. 112 115001), to include detailed measurements of the edge fluctuations and comparisons of edge simulation codes and experimental observations

Sharing brain imaging data in the Open Science era:how and why?

The sharing of human neuroimaging data has great potential to accelerate the development of imaging biomarkers in neurological and psychiatric disorders; however, major obstacles remain in terms of how and why to share data in the Open Science context. In this Health Policy by the European Cluster for Imaging Biomarkers, we outline the current main opportunities and challenges based on the results of an online survey disseminated among senior scientists in the field. Although the scientific community fully recognises the importance of data sharing, technical, legal, and motivational aspects often prevent active adoption. Therefore, we provide practical advice on how to overcome the technical barriers. We also call for a harmonised application of the General Data Protection Regulation across EU countries. Finally, we suggest the development of a system that makes data count by recognising the generation and sharing of data as a highly valuable contribution to the community.</p

Medical Interventions for Patellofemoral Pain and Patellofemoral Osteoarthritis

Patellofemoral pain (PFP) and patellofemoral osteoarthritis (PFOA) are common, persistentconditions that may lie along a pathological spectrum. While evidence supports exercise-therapyas a core treatment for PFP and PFOA, primary care physicians commonly prescribe medication,or refer for surgical consults in persistent cases. We conducted a systematic review of medicalinterventions (pharmaceutical, nutraceutical, and surgical) for PFP and PFOA to inform primarycare decision making. Methods: Following protocol registration, we searched seven databasesfor randomized clinical trials of our target interventions for PFP and PFOA. Our primary outcomewas pain. We assessed risk of bias, calculated standardized mean differences (SMDs) and determinedthe level of evidence for each intervention. Results: We included 14 publications investigatingpharmaceutical or nutraceutical interventions, and eight publications investigating surgicalinterventions. Two randomized control trials (RCTs) provided moderate evidence of patellofemoralarthroplasty having similar pain outcomes compared to total knee arthroplasty in isolated PFOA,with SMDs ranging from−0.3 (95% CI−0.8, 0.2, Western Ontario McMaster Pain Subscale, 1 yearpost-surgery) to 0.3 (−0.1, 0.7, SF-36 Bodily Pain, 2 years post-surgery). Remaining studies provided,at most, limited evidence. No efficacy was demonstrated for oral nonsteroidal anti-inflammatoriesor arthroscopic surgery. Conclusions: Pharmaceutical and nutraceutical prescriptions, and surgicalreferrals are currently being made with little supporting evidence, with some interventions showinglimited efficacy. This should be considered within the broader context of evidence supportingexercise-therapy as a core treatment for PFP and PFOA