Excitable Patterns in Active Nematics

We analyze a model of mutually-propelled filaments suspended in a two-dimensional solvent. The system undergoes a mean-field isotropic-nematic transition for large enough filament concentrations and the nematic order parameter is allowed to vary in space and time. We show that the interplay between non-uniform nematic order, activity and flow results in spatially modulated relaxation oscillations, similar to those seen in excitable media. In this regime the dynamics consists of nearly stationary periods separated by "bursts" of activity in which the system is elastically distorted and solvent is pumped throughout. At even higher activity the dynamics becomes chaotic.Comment: 4 pages, 4 figure

Defect-mediated turbulence in systems with local deterministic chaos

We show that defect-mediated turbulence can exist in media where the underlying local dynamics is deterministically chaotic. While many of the characteristics of defect-mediated turbulence, such as the exponential decay of correlations and a squared Poissonian distribution for the number of defects, are identical to those seen in oscillatory media, the fluctuations in the number of defects differ significantly. The power spectra suggest the existence of underlying correlations that lead to a different and non-universal scaling structure in chaotic media.Comment: 4 pages, 5 figure

All-Optical Modulation Via Nonlinear Cascading In Type-Ii 2Nd-Harmonic Generation

Utilizing a type II interaction for second-harmonic generation in a crystal of potassium titanyl phosphate, we experimentally demonstrate the all-optical action of a light modulator with both signal and output at the same optical wavelength. This modulator is controlled by the intensity of the injected signal, a characteristic that makes it a suitable candidate for all-optical transistor action and ultrafast analog processing in transparent networks for telecommunications

The role of the Intermediate Care Team in detecting and responding to loneliness in older clients

The Intermediate Care Team (ICT) supports patients in their own homes to manage complex needs. They are ideally placed in the community to identify older adults at risk of loneliness. However, little is known about how ICT professionals perceive, detect, or respond to loneliness in their clients. This study explores ICT professional’s attitudes to loneliness in the context of perceived service priorities and their experiences of managing loneliness in their clients. Eight ICT professionals (n=2 physiotherapists, n=3 occupational therapists, n=3 nurses) took part in semi-structured interviews. Data was analysed thematically using framework analysis, applying the Theory of Planned Behaviour as an interpretive framework. ICT professionals believed loneliness was a significant issue for many of their older clients but was a low priority for ICT services. Study participants believed that loneliness often goes undetected because it is an issue that is difficult to measure objectively. Barriers to managing loneliness included high work-load, unsatisfactory referral systems, and lack of close working with social-care and independent sector services. Introducing brief but reliable loneliness assessments into routine practice, receiving training on detecting and managing loneliness, and improving working relationships with social care and independent sector services were highlighted as strategies that could improve the detection and management of loneliness in ICT clients

Nonlinear optics: Feature issue introduction

This joint issue of Optics Express and Optical Materials Express features 18 state-of-the art articles that witness actual developments in nonlinear optics, including those by authors who participated in the international conference Nonlinear Optics held in Waikoloa, Hawaii from July 15 to 19, 2019. As an introduction, the editors provide a summary of these articles that cover all aspects of nonlinear optics, from basic nonlinear effects and novel frequency windows to innovative nonlinear materials and devices, thereby paving the way for new nonlinear optical concepts and forthcoming applications

Spatially Resolved Mapping of Local Polarization Dynamics in an Ergodic Phase of Ferroelectric Relaxor

Spatial variability of polarization relaxation kinetics in relaxor ferroelectric 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 is studied using time-resolved Piezoresponse Force Microscopy. Local relaxation attributed to the reorientation of polar nanoregions is shown to follow stretched exponential dependence, exp(-(t/tau)^beta), with beta~~0.4, much larger than the macroscopic value determined from dielectric spectra (beta~~0.09). The spatial inhomogeneity of relaxation time distributions with the presence of 100-200 nm "fast" and "slow" regions is observed. The results are analyzed to map the Vogel-Fulcher temperatures on the nanoscale.Comment: 23 pages, 4 figures, supplementary materials attached; to be submitted to Phys. Rev. Let

New Universal Strain Software Accurately Assesses Cardiac Systolic and Diastolic Function Using Speckle Tracking Echocardiography

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108658/1/echo12512.pd

Praziquantel: its use in control of schistosomiasis in sub-Saharan Africa and current research needs

Treatment with praziquantel (PZQ) has become virtually the sole basis of schistosomiasis control in sub-Saharan Africa and elsewhere, and the drug is reviewed here in the context of the increasing rate that it is being used for this purpose. Attention is drawn to our relative lack of knowledge about the mechanisms of action of PZQ at the molecular level, the need for more work to be done on schistosome isolates that have been collected recently from endemic areas rather than those maintained in laboratory conditions for long periods, and our reliance for experimental work mainly on Schistosoma mansoni, little work having been done on S. haematobium. There is no evidence that resistance to PZQ has been induced in African schistosomes as a result of its large-scale use on that continent to date, but there is also no assurance that PZQ and/or schistosomes are in any way unique and that resistant organisms will not be selected as a result of widespread drug usage. The failure of PZQ to produce complete cures in populations given a routine treatment should therefore solicit considerable concern. With few alternatives to PZQ currently available and/or on the horizon, methods to monitor drug-susceptibility in African schistosomes need to be devised and used to help ensure that this drug remains effective for as long a time as possibl