Reversible signal transmission in an active mechanical metamaterial

Mechanical metamaterials are designed to enable unique functionalities, but are typically limited by an initial energy state and require an independent energy input to function repeatedly. Our study introduces a theoretical active mechanical metamaterial that incorporates a biological reaction mechanism to overcome this key limitation of passive metamaterials. Our material allows for reversible mechanical signal transmission, where energy is reintroduced by the biologically motivated reaction mechanism. By analysing a coarse grained continuous analogue of the discrete model, we find that signals can be propagated through the material by a travelling wave. Analysis of the continuum model provides the region of the parameter space that allows signal transmission, and reveals similarities with the well-known FitzHugh-Nagumo system. We also find explicit formulae that approximate the effect of the timescale of the reaction mechanism on the signal transmission speed, which is essential for controlling the material.Comment: 20 pages, 7 figure

Long Wavelength SAR Backscatter Modelling Trends as a Consequence of the Emergent Properties of Tree Populations

www.mdpi.com/journal/remotesensin

Infantile nystagmus: an optometrist's perspective

Infantile nystagmus (IN), previously known as congenital nystagmus, is an involuntary to-and-fro movement of the eyes that persists throughout life. IN is one of three types of early-onset nystagmus that begin in infancy, alongside fusion maldevelopment nystagmus syndrome and spasmus nutans syndrome. Optometrists may also encounter patients with acquired nystagmus. The features of IN overlap largely with those of fusion maldevelopment nystagmus syndrome, spasmus nutans syndrome, and acquired nystagmus, yet the management for each subtype is different. Therefore, the optometrist’s role is to accurately discern IN from other forms of nystagmus and to manage accordingly. As IN is a lifelong condition, its presence not only affects the visual function of the individual but also their quality of life, both socially and psychologically. In this report, we focus on the approaches that involve optometrists in the investigation and management of patients with IN. Management includes the prescription of optical treatments, low-vision rehabilitation, and other interventions such as encouraging the use of the null zone and referral to support groups. Other treatments available via ophthalmologists are also briefly discussed in the article

Interventions for drug-using offenders with co-occurring mental illness: : A systematic review and economic appraisal

Background: Drug-using offenders with co-occurring mental health problems are common in the criminal justice system. A combination of drug use and mental health problems makes people more likely to be arrested for criminal involvement after release compared to offenders without a mental health problem. Previous research has evaluated interventions aimed broadly at those with a drug problem but rarely with drug use and mental health problems. This systematic review considers the effectiveness of interventions for drug-using offenders with co-occurring mental health problems. Methods: We searched 14 electronic bibliographic databases up to May 2014 and five Internet resources. The review included randomised controlled trials designed to reduce, eliminate, or prevent relapse of drug use and/or criminal activity. Data were reported on drug and crime outcomes, the identification of mental health problems, diagnoses and resource information using the Drummond checklist. The systematic review used standard methodological procedures as prescribed by the Cochrane collaboration. Results: Eight trials with 2058 participants met the inclusion criteria. These evaluated: case management (RR, 1.05, 95 % CI 0.90 to 1.22, 235 participants), motivational interviewing and cognitive skills, (MD-7.42, 95 % CI-0.20.12 to 5.28, 162 participants) and interpersonal psychotherapy (RR 0.67, 95 % CI 0.3 to 1.5, 38 participants). None of these trials reported significant reductions in self-report drug misuse or crime. Four trials evaluating differing therapeutic community models showed reductions in re-incarceration (RR 0.28, 95 % CI 0.13 to 0.63, 139 participants) but not re-arrest (RR 1.65, 95 % CI 0.83 to 3.28, 370 participants) or self-report drug use (RR 0.73, 95 % CI 0.53 to 1.01, 370 participants). Mental health problems were identified across the eight trials and 17 different diagnoses were described. Two trials reported some resource information suggesting a cost-beneficial saving when comparing therapeutic communities to a prison alternative. Conclusions: Overall, the studies showed a high degree of variation, warranting a degree of caution in the interpretation of the magnitude of effect and direction of benefit for treatment outcomes. Specifically, tailored interventions are required to assess the effectiveness of interventions for drug-using offenders with co-occurring mental health problems

Attention to Authority: The behavioural finance of Covid-19

In this paper we investigate the predictability of cryptocurrency returns following increases in Covid-19 cases/deaths. We find that the rate of government intervention moderates the impact that Covid-19 cases/deaths have on cryptocurrency returns. We show that in periods of tightening government intervention, increases in Covid-19 cases positively predict cryptocurrency returns. We argue that this is due to investors imputing their expectations of the pandemic through a ‘combined’ signal

The effect of gaze angle on visual acuity in infantile nystagmus

Purpose: Most individuals with infantile nystagmus (IN) have an idiosyncratic gaze angle at which their nystagmus intensity is minimized. Some adopt an abnormal head posture to use this “null zone,” and it has therefore long been assumed that this provides people with nystagmus with improved visual acuity (VA). However, recent studies suggest that improving the nystagmus waveform could have little, if any, influence on VA; that is, VA is fundamentally limited in IN. Here, we examined the impact of the null zone on VA. Methods: Visual acuity was measured in eight adults with IN using a psychophysical staircase procedure with reversals at three horizontal gaze angles, including the null zone. Results: As expected, changes in gaze angle affected nystagmus amplitude, frequency, foveation duration, and variability of intercycle foveation position. Across participants, each parameter (except frequency) was significantly correlated with VA. Within any given individual, there was a small but significant improvement in VA (0.08 logMAR) at the null zone as compared with the other gaze angles tested. Despite this, no change in any of the nystagmus waveform parameters was significantly associated with changes in VA within individuals. Conclusions: A strong relationship between VA and nystagmus characteristics exists between individuals with IN. Although significant, the improvement in VA observed within individuals at the null zone is much smaller than might be expected from the occasionally large variations in intensity and foveation dynamics (and anecdotal patient reports of improved vision), suggesting that improvement of other aspects of visual performance may also encourage use of the null zone

Technological advances in maize breeding: past, present and future

Maize has for many decades been both one of the most important crops worldwide and one of the primary genetic model organisms. More recently, maize breeding has been impacted by rapid technological advances in sequencing and genotyping technology, transformation including genome editing, doubled haploid technology, parallelled by progress in data sciences and the development of novel breeding approaches utilizing genomic information. Herein, we report on past, current and future developments relevant for maize breeding with regard to (1) genome analysis, (2) germplasm diversity characterization and utilization, (3) manipulation of genetic diversity by transformation and genome editing, (4) inbred line development and hybrid seed production, (5) understanding and prediction of hybrid performance, (6) breeding methodology and (7) synthesis of opportunities and challenges for future maize breeding

Visual processing in infantile nystagmus is not slow

Purpose: Treatments for infantile nystagmus (IN) sometimes elicit subjective reports of improved visual function, yet quantifiable improvements in visual acuity, if any, are often negligible. One possibility is that these subjective “improvements” may relate to temporal, rather than spatial, visual function. This study aimed to ascertain the extent to which “time to see” might be increased in nystagmats, as compared to normally sighted controls. By assessing both eye movement and response time data, it was possible to determine whether delays in “time to see” were due solely to the eye movements, or to an underlying deficit in visual processing. Methods: The time taken to respond to the orientation of centrally and peripherally presented gratings was measured in subjects with IN and normally sighted controls (both groups: n = 11). For each vertically displaced grating, the time until the target-acquiring saccade was determined, as was the time from the saccade until the subject's response. Results: Nystagmats took approximately 60 ms longer than controls to execute target-acquiring saccades to vertically displaced targets (P = 0.010). However, the time from the end of the saccade until subjects responded was not significantly different between groups (P = 0.37). Despite this, nystagmats took longer to respond to gratings presented at fixation. Conclusions: Individuals with IN took longer to direct their gaze toward objects of interest. However, once a target was foveated, the time taken to process visual information and respond did not appear to differ from that of control subjects. Therefore, conscious visual processing in IN is not slow