Incentive-based approaches to sustainable fisheries

The failures of traditional target-species management have led many to propose an ecosystem approach to fisheries to promote sustainability. The ecosystem approach is necessary, especially to account for fishery-ecosystem interactions, but by itself is not sufficient to address two important factors contributing to unsustainable fisheries — inappropriate incentives bearing on fishers, and the ineffective governance that frequently exists in commercial, developed fisheries managed primarily by total harvest limits and input-controls. We contend that much greater emphasis must be placed on fisher motivation when managing fisheries. Using evidence from more than a dozen ‘natural experiments’ in commercial fisheries, we argue that incentive-based approaches that better specify community, individual harvest, or territorial rights and also price ecosystem services — coupled with public research, monitoring and effective oversight — promote sustainable fisheries.incentives, sustainability, rights, fisheries management

Incentive-based approaches to sustainable fisheries (now replaced by EEN0508)

Using examples from more than a dozen fisheries, we highlight the failures of ‘command control’ management and show that approaches that empower fishers with the incentives and the mandate to be co-custodians of the marine environment can promote sustainability. Evidence is provided that where harvesters share well-defined management responsibilities over fish, and experience both the pain of overexploitation and the gains from conservation, they are much more likely to protect fish stocks and habitat. The key insight is that to maintain marine ecosystems for present and future generations, fishing incentives must be compatible with long-term goals of sustainability.incentives, sustainability, rights, fisheries management

Large-area 2D selective area growth for photonic crystal surface emitting lasers

We report an investigation into large-area selective area growth of InGaAs/GaAs quantum wells by metalorganic vapour phase epitaxy. The emission wavelength tuning range, growth enhancement, and uniformity of material deposited within square masked regions with central square growth windows with widths in the range of 100–300 μm are studied. Micro-photoluminescence measurements at the centre point of each of the growth windows reveals a total wavelength tuning range of 86 nm across all samples, with a typical tuning range of 30 nm for a given window width, dependent upon dielectric mask width. The thickness enhancement in each of features, as determined by white-light interferometric profiling, indicates that centre point growth rate enhancements of between 1.19 and 2.23× are achieved with respect to the nominal epitaxial structure. By comparing the observed emission wavelengths with those simulated using the enhanced quantum well thicknesses, a range of indium concentrations between 12 and 17 % is calculated for the material at the centre of each feature. Two-dimensional analysis of selected features reveals that areas with uniform emission wavelength up to 100 × 100 μm2 in size can be achieved for the mask patterns used, indicating suitability for future applications in the fabrication of monolithically integrated multi-wavelength photonic crystal surface emitting laser arrays

Adherence to self-administered tuberculosis treatment in a high HIV-prevalence setting: a cross-sectional survey in Homa Bay, Kenya.

Good adherence to treatment is crucial to control tuberculosis (TB). Efficiency and feasibility of directly observed therapy (DOT) under routine program conditions have been questioned. As an alternative, Médecins sans Frontières introduced self-administered therapy (SAT) in several TB programs. We aimed to measure adherence to TB treatment among patients receiving TB chemotherapy with fixed dose combination (FDC) under SAT at the Homa Bay district hospital (Kenya). A second objective was to compare the adherence agreement between different assessment tools

Small signal modulation of photonic crystal surface emitting lasers

We report the small-signal characterization of a PCSEL device, extracting damping factors and modulation efficiencies, and demonstrating -3 dB modulation bandwidths of up to 4.26 GHz. Based on modelling we show that, by reducing the device width and improving the active region design for high-speed modulation, direct modulation frequencies in excess of 50 GHz are achievable

Resonator embedded photonic crystal surface emitting lasers

The finite size of 2D photonic crystals results in them being a lossy resonator, with the normally emitting modes of conventional photonic crystal surface emitting lasers (PCSELs) differing in photon lifetime via their different radiative rates, and the different in-plane losses of higher order spatial modes. As a consequence, the fundamental spatial mode (lowest in-plane loss) with lowest out-of-plane scattering is the primary lasing mode. For electrically driven PCSELs, as current is increased, incomplete gain clamping results in additional spatial (and spectral) modes leading to a reduction in beam quality. A number of approaches have been discussed to enhance the area (power) scalability of epitaxy regrown PCSELs through careful design of the photonic crystal atom1–3. None of these approaches tackle the inflexibility in being unable to independently modify the photon lifetime of the different modes at the Γ2 point. As a method to introduce design flexibility, resonator embedded photonic crystal surface emitting lasers (REPCSELs) are introduced. This device, combining comparatively low coupling strength photonic crystal structures along with perimeter mirrors, allow a Fabry–Pérot resonance effect to be realised that provides wavelength selective modification of the photon lifetime. We show that surface emission of different surface emitting modes may be selectively enhanced, effectively changing the character of the modes at the Γ2 point. This is a consequence of the selective modification of in-plane loss for particular modes, and is dependent upon the alignment of the photonic crystal (PhC) band-structure and distributed Bragg reflectors’ (DBRs) reflectance spectrum. These findings offer new avenues in surface emitting laser diode engineering. The use of DBRs to reduce the lateral size of a PCSEL opens the route to small, low threshold current (Ith), high output efficiency epitaxy regrown PCSELs for high-speed communication and power sensitive sensing applications

AEROBIC AND ANAEROBIC SCALING IN FISH

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75506/1/j.1469-185X.1991.tb01134.x.pd

Post-acute COVID-19 neuropsychiatric symptoms are not associated with ongoing nervous system injury

A proportion of patients infected with severe acute respiratory syndrome coronavirus 2 experience a range of neuropsychiatric symptoms months after infection, including cognitive deficits, depression and anxiety. The mechanisms underpinning such symptoms remain elusive. Recent research has demonstrated that nervous system injury can occur during COVID-19. Whether ongoing neural injury in the months after COVID-19 accounts for the ongoing or emergent neuropsychiatric symptoms is unclear. Within a large prospective cohort study of adult survivors who were hospitalized for severe acute respiratory syndrome coronavirus 2 infection, we analysed plasma markers of nervous system injury and astrocytic activation, measured 6 months post-infection: neurofilament light, glial fibrillary acidic protein and total tau protein. We assessed whether these markers were associated with the severity of the acute COVID-19 illness and with post-acute neuropsychiatric symptoms (as measured by the Patient Health Questionnaire for depression, the General Anxiety Disorder assessment for anxiety, the Montreal Cognitive Assessment for objective cognitive deficit and the cognitive items of the Patient Symptom Questionnaire for subjective cognitive deficit) at 6 months and 1 year post-hospital discharge from COVID-19. No robust associations were found between markers of nervous system injury and severity of acute COVID-19 (except for an association of small effect size between duration of admission and neurofilament light) nor with post-acute neuropsychiatric symptoms. These results suggest that ongoing neuropsychiatric symptoms are not due to ongoing neural injury

Concurrent Shadow Paging in the Flask Architecture

The differing requirements for concurrency models in programming languages and databases are widely diverse and often seemingly incompatible. The rigid provision of a particular concurrency control scheme in a persistent object system limits its usefulness to a particular class of application, in contrast to the generality intended by the provision of persistence. One solution is to provide a flexible system in which concurrency control schemes may be specified according to the particular task in hand, allowing the same data to be used in conjunction with different concurrency control schemes according to the needs of the application. A major difficulty in the engineering of such a system lies in the building of generic mechanisms to provide the facilities of data visibility restriction, stability, and atomicity, independently of the combination of these employed by a particular concurrency control scheme. Flask is a architecture which is designed to achieve this goal by defining a lay..