Firefly Flashing is Controlled by Gating Oxygen to Light-Emitting Cells

Although many aspects of firefly bioluminescence are understood, the mechanism by which adult fireflies produce light as discrete rapid flashes is not. Here we examine the most postulated theory, that flashing is controlled by gating oxygen access to the light-emitting cells (photocytes). According to this theory, the dark state represents repression of bioluminescence by limiting oxygen, which is required for bioluminescence; relief from this repression by transiently allowing oxygen access to the photocytes allows the flash. We show that normobaric hyperoxia releases the repression of light emission in the dark state of both spontaneously flashing and non-flashing fireflies, causing continual glowing, and we measure the kinetics of this process. Secondly, we determine the length of the barriers to oxygen diffusion to the photocytes in the aqueous and gas phases. Thirdly, we provide constraints upon the distance between any gas-phase gating structure(s) and the photocytes. We conclude from these data that the flash of the adult firefly is controlled by gating of oxygen to the photocytes, and demonstrate that this control mechanism is likely to act by modulating the levels of fluid in the tracheoles supplying photocytes, providing a variable barrier to oxygen diffusion

Differences in level of confidence in diabetes care between different groups of trainees: the TOPDOC diabetes study

Background There is an increasing prevalence of diabetes. Doctors in training, irrespective of specialty, will have patients with diabetes under their care. The aim of this further evaluation of the TOPDOC Diabetes Study data was to identify if there was any variation in confidence in managing diabetes depending on the geographical location of trainees and career aspirations. Methods An online national survey using a pre-validated questionnaire was administered to trainee doctors. A 4-point confidence rating scale was used to rate confidence in managing aspects of diabetes care and a 6-point scale used to quantify how often trainees would contribute to the management of patients with diabetes. Responses were grouped depending on which UK country trainees were based and their intended career choice. Results Trainees in Northern Ireland reported being less confident in IGT diagnosis, use of IV insulin and peri-operative management and were less likely to adjust oral treatment, contact specialist, educate lifestyle, and optimise treatment. Trainees in Scotland were less likely to contact a specialist, but more likely to educate on lifestyle, change insulin, and offer follow-up advice. In Northern Ireland, Undergraduate (UG) and Postgraduate (PG) training in diagnosis was felt less adequate, PG training in emergencies less adequate, and reporting of need for further training higher. Trainees in Wales felt UG training to be inadequate. In Scotland more trainees felt UG training in diagnosis and optimising treatment was inadequate. Physicians were more likely to report confidence in managing patients with diabetes and to engage in different aspects of diabetes care. Aspiring physicians were less likely to feel the need for more training in diabetes care; however a clear majority still felt they needed more training in all aspects of care. Conclusions Doctors in training have poor confidence levels dealing with diabetes related care issues. Although there is variability between different groups of trainees according to geographical location and career aspirations, this is a UK wide issue. There should be a UK wide standardised approach to improving training for junior doctors in diabetes care with local training guided by specific needs.</p

Design and Management of Saltbush-Based Forage Systems to Improve Productivity and Reproductive Performance of Sheep

There is evidence that effective shelter can significantly improve lamb survival, but the majority of Australian studies have occurred in small paddocks where the ewes had no choice but to use shelter. In mixed farming systems with large open paddocks, it is unclear if ewes will choose to use shelter for lambing. Our multidisciplinary collaboration examines the use of woody shrubs as an opportunity to improve the survival of twin lambs. In a series of large experiments on commercial farms, we will evaluate the impact of different shrub planting configurations, orientations, and densities on microclimates at the sub-paddock scale. Twin-bearing ewes with GPS trackers will graze a mosaic of shelter options to identify lambing sites relative to climatic conditions at the time of lambing. Relatively palatable and unpalatable shrubs have been planted to explore trade-offs between the attraction of ewes to shelter against declining shelter value, because palatable shrubs are defoliated faster than relatively unpalatable options. A linked project is investigating the use of the same shrub systems to provide shade and antioxidants during joining when temperatures exceed the sheep thermal comfort zone for extended periods in summer. Hardy perennial shrubs such as saltbush offer an opportunity to improve profitability and climate resilience of farming systems, while improving landscape health. Multidisciplinary research is required to understand the benefits and limitations of these systems

Managing Human-Habituated Bears to Enhance Survival, Habitat Effectiveness, and Public Viewing

The negative impacts on bears (Ursus spp.) from human activities associated with roads and developments are well documented. These impacts include displacement of bears from high-quality foods and habitats, diminished habitat effectiveness, and reduced survival rates. Additionally, increased public visitations to national parks accompanied with benign encounters with bears along park roads have caused more bears to habituate to the presence of people. In some contexts, habituation can predispose bears to being exposed to and rewarded by anthropogenic foods, which can also lower survival rates. The managers and staff of Yellowstone National Park located in Wyoming, Montana, and Idaho, USA, and Grand Teton National Park in northwestern Wyoming, USA have implemented several proactive strategies to mitigate the negative aspects of bear habituation. These strategies include providing park visitors with educational information on bear viewing etiquette, managing roadside viewing opportunities, installing bear-resistant infrastructure, hazing bears from developments, enforcing food and garbage storage regulations, and making human activities as predictable as possible to bears. Under the current management strategies, thousands of visitors are still able to view, photograph, and appreciate bears while visiting these parks each year. The opportunity to view bears provides a positive visitor experience and contributes millions of dollars to the local economies of park gateway communities. Positive bear viewing experiences also help build an important appreciation and conservation ethic for bears in people that visit national parks. For many years, managers were concerned about decreasing and threatened bear populations. Now more jurisdictions are facing new challenges caused by increasing bear populations. This paper highlights a successful attempt to address these issues

Sustainable Grazing on Saline Land in Western Australia - Multidisciplinary Research Linking Producers and Scientists

Dryland salinity is one of the most critical environmental issues challenging Western Australian farmers. Currently 10% of the cropping zone (1.8 million ha) is salt-affected and this is predicted to increase dramatically in the next 50 years (NLWRA, 2001). Animals grazing saline pasture systems represent the most likely large-scale opportunity for economic return from saline land in the short to medium term. To date, few farmers have invested in large-scale revegetation of saline land as the economic return from grazing has not been perceived to cover costs. Furthermore other benefits of saltland pasture systems, such as biodiversity, water use and improved quality of animal products have not been quantified

Domestication of the Annual Legume \u3cem\u3eTrigonella balansae\u3c/em\u3e for Mixed Farming Systems in Southern Australia

An accession of the annual legume Trigonella balansae Boiss. and Reuter. has been selected for commercial release in Australia. The annual legume has significant potential as a self-regenerating pasture within mixed farming systems. As part of a duty-of-care assessment, we tested the hypothesis that sheep grazing the trigonella cultivar will have similar liveweight, condition scores, health and wool production to sheep grazing two widely adopted annual legumes, subterranean clover (Trifolium subterraneum L. cv Dalkeith) and French serradella (Ornithopus sativus Brot. cv. Erica). Forage dry matter digestibility (DMD), crude protein (CP), fibre, mineral content and isoflavones were measured across the plant’s lifecycle. The data supported the hypotheses and there were no significant differences in liveweight, wool growth, wool yield or condition score that were associated with pasture species. The mineral content of trigonella requires further investigation

Evidence for density-dependent effects on body composition of a large omnivore in changing Greater Yellowstone Ecosystem

Understanding the density-dependent processes that drive population demography in a changing world is critical in ecology, yet measuring performance–density relationships in long-lived mammalian species demands long-term data, limiting scientists' ability to observe such mechanisms. We tested performance–density relationships for an opportunistic omnivore, grizzly bears (Ursus arctos, Linnaeus, 1758) in the Greater Yellowstone Ecosystem, with estimates of body composition (lean body mass and percent body fat) serving as indicators of individual performance over two decades (2000–2020) during which time pronounced environmental changes have occurred. Several high-calorie foods for grizzly bears have mostly declined in recent decades (e.g., whitebark pine [Pinus albicaulis, Engelm, 1863]), while increasing human impacts from recreation, development, and long-term shifts in temperatures and precipitation are altering the ecosystem. We hypothesized that individual lean body mass declines as population density increases (H1), and that this effect would be more pronounced among growing individuals (H2). We also hypothesized that omnivory helps grizzly bears buffer energy intake from changing foods, with body fat levels being independent from population density and environmental changes (H3). Our analyses showed that individual lean body mass was negatively related to population density, particularly among growing-age females, supporting H1 and partially H2. In contrast, population density or sex had little effect on body fat levels and rate of accumulation, indicating that sufficient food resources were available on the landscape to accommodate successful use of shifting food sources, supporting H3. Our results offer important insights into ecological feedback mechanisms driving individual performances within a population undergoing demographic and ecosystem-level changes. However, synergistic effects of continued climate change and increased human impacts could lead to more extreme changes in food availability and affect observed population resilience mechanisms. Our findings underscore the importance of long-term studies in protected areas when investigating complex ecological relationships in an increasingly anthropogenic worl

Is null-point reconnection important for solar flux emergence?

The role of null-point reconnection in a 3D numerical MHD model of solar emerging flux is investigated. The model consists of a twisted magnetic flux tube rising through a stratified convection zone and atmosphere to interact and reconnect with a horizontal overlying magnetic field in the atmosphere. Null points appear as the reconnection begins and persist throughout the rest of the emergence, where they can be found mostly in the model photosphere and transition region, forming two loose clusters on either side of the emerging flux tube. Up to 26 nulls are present at any one time, and tracking in time shows that there is a total of 305 overall, despite the initial simplicity of the magnetic field configuration. We find evidence for the reality of the nulls in terms of their methods of creation and destruction, their balance of signs, their long lifetimes, and their geometrical stability. We then show that due to the low parallel electric fields associated with the nulls, null-point reconnection is not the main type of magnetic reconnection involved in the interaction of the newly emerged flux with the overlying field. However, the large number of nulls implies that the topological structure of the magnetic field must be very complex and the importance of reconnection along separators or separatrix surfaces for flux emergence cannot be ruled out.Comment: 26 pages, 12 figures. Added one referenc

Safety and Efficacy of Omaveloxolone in Friedreich Ataxia (MOXIe Study)

OBJECTIVE: Friedreich's ataxia (FRDA) is a progressive genetic neurodegenerative disorder with no approved treatment. Omaveloxolone, an Nrf2 activator, improves mitochondrial function, restores redox balance, and reduces inflammation in models of FRDA. We investigated the safety and efficacy of omaveloxolone in patients with FRDA. METHODS: We conducted an international, double-blind, randomized, placebo-controlled parallel-group, registrational phase 2 trial at 11 institutions in the United States, Europe, and Australia (NCT02255435, EudraCT2015-002762-23). Eligible patients, 16 to 40 years of age with genetically confirmed FRDA and baseline modified Friedreich's Ataxia Rating Scale (mFARS) scores between 20 and 80, were randomized 1:1 to placebo or 150 mg per day of omaveloxolone. The primary outcome was change from baseline in the mFARS score in those treated with omaveloxolone compared with those on placebo at 48 weeks. RESULTS: 155 patients were screened and 103 were randomly assigned to receive omaveloxolone (n=51) or placebo (n=52), with 40 omaveloxolone patients and 42 placebo patients analyzed in the full analysis set. Changes from baseline in mFARS scores in omaveloxolone (-1.55 ± 0.69) and placebo (0.85 ± 0.64) patients showed a difference between treatment groups of -2.40 ± 0.96; p=0.014). Transient reversible increases in aminotransferase levels were observed with omaveloxolone without increases in total bilirubin or other signs of liver injury. Headache, nausea, and fatigue were also more common among patients receiving omaveloxolone. INTERPRETATION: In the MOXIe trial, omaveloxolone significantly improved neurological function compared to placebo and was generally safe and well tolerated. It represents a potential therapeutic agent in FRDA. This article is protected by copyright. All rights reserved

Lack of confidence among trainee doctors in the management of diabetes: the Trainees Own Perception of Delivery of Care (TOPDOC) Diabetes Study

Background: There is an increased prevalence of diabetes. Doctors in training, irrespective of specialty, will have patients with diabetes under their care