Critical jamming of frictional grains in the generalized isostaticity picture

While frictionless spheres at jamming are isostatic, frictional spheres at jamming are not. As a result, frictional spheres near jamming do not necessarily exhibit an excess of soft modes. However, a generalized form of isostaticity can be introduced if fully mobilized contacts at the Coulomb friction threshold are considered as slipping contacts. We show here that, in this framework, the vibrational density of states (DOS) of frictional discs exhibits a plateau when the generalized isostaticity line is approached. The crossover frequency to elastic behavior scales linearly with the distance from this line. Moreover, we show that the frictionless limit, which appears singular when fully mobilized contacts are treated elastically, becomes smooth when fully mobilized contacts are allowed to slip.Comment: 4 pages, 4 figures, submitted to PR

A Swimming Program for Children with Autism Spectrum Disorders: Assessing Critical Parameters from Caregivers’ Perspectives

One in 54 individuals is diagnosed with autism spectrum disorders (ASD). Swimming can impact the physical and mental well-being of persons with ASD, which in turn may improve their caregivers’ well-being. The purpose of this qualitative evaluation study is to assess the necessity, acceptability, feasibility, fidelity, and beginning effectiveness of a 12-session swimming training program (STP) at an indoor university pool designed to teach persons with ASD how to swim, and to teach caregivers precautions for safety around water. Participants included 7 boys, and 3 girls with ASD [mean age 7.05 years (SD 1.17)] and their caregivers. Results indicated that caregivers reported a need for this STP and the content was appropriate. Participants indicated the instructors’ creativity and patience as well as social interaction were the most interesting/acceptable part of the STP. The number of lessons and length of the STP were considered appropriate. Evaluating these critical parameters of the STP from caregivers’ perspectives was essential as this will likely influence their future participation in swimming programs

Multi-strange baryon elliptic flow in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV measured with the ALICE detector

We present the results on elliptic flow with multi-strange baryons produced in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV. The analysis is performed with the ALICE detector at LHC. Multi-strange baryons are reconstructed via their decay topologies and the v_2 values are analyzed with the two-particle scalar product method. The p_T differential v_2 values are compared to the VISH2+1 model calculation and to the STAR measurements at 200 GeV in Au+Au collisions. We found that the model describes \Xi and \Omega v_2 measurements within experimental uncertainties. The differential flow of \Xi and \Omega is similar to the STAR measurements at 200 GeV in Au+Au collisions.Comment: Prepared for the Proceedings of the International Conference on "Critical Point and Onset of Deconfinement - CPOD 2011", Wuhan, November 7-11, 201

Force Dynamics in Weakly Vibrated Granular Packings

The oscillatory force F_b^ac on the bottom of a rigid, vertically vibrated, grain filled column, reveals rich granular dynamics, even when the peak acceleration of the vibrations is signicantly less than the gravitational acceleration at the earth's surface. For loose packings or high frequencies, F_b^ac 's dynamics are dominated by grain motion. For moderate driving conditions in more compact samples, grain motion is virtually absent, but F_b^ac nevertheless exhibits strongly nonlinear and hysteretic behavior, evidencing a granular regime dominated by nontrivial force-network dynamics.Comment: 4 pages, 5 figure

MR Imaging of Reynolds Dilatancy in the Bulk of Smooth Granular Flows

Article / Letter to editorLeiden Instituut Onderzoek Natuurkund

Simultaneous Robotic Manipulation and Functional Magnetic Resonance Imaging: Feasibility in Children with Autism Spectrum Disorders

An unanswered question concerning the neural basis of autism spectrum disorders (ASD) is how sensorimotor deficits in individuals with ASD are related to abnormalities of brain function. We previously described a robotic joystick and video game system that allows us to record functional magnetic resonance images (FMRI) while adult humans make goal- directed wrist motions. We anticipated several challenges in extending this approach to studying goal-directed behaviors in children with ASD and in typically developing (TYP) children. In particular we were concerned that children with autism may express increased levels of anxiety as compared to typically developing children due to the loud sounds and small enclosed space of the MRI scanner. We also were concerned that both groups of children might become restless during testing, leading to an unacceptable amount of head movement. Here we performed a pilot study evaluating the extent to which autistic and typically developing children exhibit anxiety during our experimental protocol as well as their ability to comply with task instructions. Our experimental controls were successful in minimizing group differences in drop-out due to anxiety. Kinematic performance and head motion also were similar across groups. Both groups of children engaged cortical regions (frontal, parietal, temporal, occipital) while making goal- directed movements. In addition, the ASD group exhibited task- related correlations in subcortical regions (cerebellum, thalamus), whereas correlations in the TYP group did not reach statistical significance in subcortical regions. Four distinct regions in frontal cortex showed a significant group difference such that TYP children exhibited positive correlations between the hemodynamic response and movement, whereas children with ASD exhibited negative correlations. These findings demonstrate feasibility of simultaneous application of robotic manipulation and functional imaging to study goal-directed motor behaviors in autistic and typically developing children. The findings also suggest the presence of marked changes in neural activation during a sensorimotor task requiring goal- directed movement

A Swimming Program for Children with Autism Spectrum Disorders: Assessing Critical Parameters from Caregivers’ Perspectives

One in 54 individuals is diagnosed with autism spectrum disorders (ASD). Swimming can impact the physical and mental well-being of persons with ASD, which in turn may improve their caregivers’ well-being. The purpose of this qualitative evaluation study is to assess the necessity, acceptability, feasibility, fidelity, and beginning effectiveness of a 12-session swimming training program (STP) at an indoor university pool designed to teach persons with ASD how to swim, and to teach caregivers precautions for safety around water. Participants included 7 boys, and 3 girls with ASD [mean age 7.05 years (SD 1.17)] and their caregivers. Results indicated that caregivers reported a need for this STP and the content was appropriate. Participants indicated the instructors’ creativity and patience as well as social interaction were the most interesting/acceptable part of the STP. The number of lessons and length of the STP were considered appropriate. Evaluating these critical parameters of the STP from caregivers’ perspectives was essential as this will likely influence their future participation in swimming programs

Towards a standard MRI protocol for multiple sclerosis across the UK.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating and degenerative disease of the central nervous system. It is the most common non-traumatic cause of chronic disability in young adults. An early and accurate diagnosis, and effective disease modifying treatment (DMT) are key elements of optimum care for people with MS (pwMS). Magnetic resonance imaging (MRI) has become a critical tool to confirm the presence of dissemination in space and time of lesions characteristic of inflammatory demyelination, a cornerstone of MS diagnosis, over and above exclusion of numerous differential diagnoses. In the modern era of early and highly effective DMT, follow-up of pwMS also relies heavily on MRI, to both confirm efficacy and for pharmacovigilance. Since criteria for MS rely heavily on MRI, an agreed standardized acquisition and reporting protocol enabling efficient and equitable application across the UK is desirable. Following a recent meeting of MS experts in London (UK), we make recommendations for a standardized UK MRI protocol that captures the diagnostic phase as well as monitoring for safety and treatment efficacy once the diagnosis is established. Our views take into account issues arising from the (repeated) use of contrast agents as well as the advent of (semi-) automated tools to further optimise disease monitoring in pwMS.Edmond J Safra FoundationLily SafraMRCUK Dementia Research InstituteImperial College Healthcare Trust Biomedical Research Centr

Clinician-targeted interventions to reduce antibiotic prescribing for acute respiratory infections in primary care:An overview of systematic reviews

This is the protocol for a review and there is no abstract. The objectives are as follows: To systematically review the literature and appraise the existing evidence from systematic reviews regarding the effects of interventions, aimed at changing clinician behaviour, to reduce antibiotic prescribing for ARIs in primary care