737 research outputs found

    Restoration of Lake Hakanoa: Results of model simulations

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    This report was requested by Waikato District Council. It covers the lake water quality of, and possible restoration scenarios for, Lake Hakanoa a riverine lake situated in Huntly. The lake is used as a recreational resource by the community. In the past it has been reported to have had very poor water quality and is known to be eutrophic. It is currently in an algal-dominated, devegetated state and has low water clarity. The shallowness of this lake makes it potentially susceptible to resuspension of sediments through wind action. A community group, Friends of Hakanoa, has been responsible for the formation of a path around the perimeter of the lake, retiring about 3.6% of the catchment from pastoral farming and creating a riparian margin. Results from more recent reports and this report indicate a trend of improving water quality which may be related to recent restoration actions such as re-establishment of a riparian margin

    Biophysical Features of Bacillithiol, the Glutathione Surrogate of Bacillus subtilis and other Firmicutes

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    Bacillithiol (BSH) is the major low-molecular-weight (LMW) thiol in many low-G+C Gram-positive bacteria (Firmicutes). Evidence now emerging suggests that BSH functions as an important LMW thiol in redox regulation and xenobiotic detoxification, analogous to what is already known for glutathione and mycothiol in other microorganisms. The biophysical properties and cellular concentrations of such LMW thiols are important determinants of their biochemical efficiency both as biochemical nucleophiles and as redox buffers. Here, BSH has been characterised and compared with other LMW thiols in terms of its thiol pKa, redox potential and thiol–disulfide exchange reactivity. Both the thiol pKa and the standard thiol redox potential of BSH are shown to be significantly lower than those of glutathione whereas the reactivities of the two compounds in thiol–disulfide reactions are comparable. The cellular concentration of BSH in Bacillus subtilis varied over different growth phases and reached up to 5 mM, which is significantly greater than previously observed from single measurements taken during mid-exponential growth. These results demonstrate that the biophysical characteristics of BSH are distinctively different from those of GSH and that its cellular concentrations can reach levels much higher than previously reported

    Zero-Energy Modes from Coalescing Andreev States in a Two-Dimensional Semiconductor-Superconductor Hybrid Platform

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    We investigate zero-bias conductance peaks that arise from coalescing subgap Andreev states, consistent with emerging Majorana zero modes, in hybrid semiconductor-superconductor wires defined in a two-dimensional InAs/Al heterostructure using top-down lithography and gating. The measurements indicate a hard superconducting gap, ballistic tunneling contact, and in-plane critical fields up to 33~T. Top-down lithography allows complex geometries, branched structures, and straightforward scaling to multicomponent devices compared to structures made from assembled nanowires.Comment: Includes Supplementary Materia

    Mass spectrometric detection of iron nitrosyls, sulfide oxidation and mycothiolation during nitrosylation of the NO sensor [4Fe-4S] NsrR

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    Identification of RRE-type iron-nitrosyl species formed upon nitrosylation of [4Fe–4S] NsrR.</p

    Mass spectrometric studies of Cu(I)-binding to the N-terminal domains of B. subtilis CopA and influence of bacillithiol

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    CopA is a Cu(I)-exporting transmembrane P1B-type ATPase from Bacillus subtilis. It contains two N-terminal cytoplasmic domains, CopAab, which bind Cu(I) with high affinity and to form higher-order complexes with multiple Cu(I) ions. To determine the precise nature of these species, electrospray ionisation mass spectrometry (ESI-MS) under non-denaturing conditions was employed. Up to 1 Cu per CopAab resulted in Cu coordination to one or both CopAab domains. At >1 Cu/CopAab, two distinct dimeric charge state envelopes were observed, corresponding to distinct conformations, each with Cu6(CopAab)2 as its major form. The influence of the physiologically relevant low molecular weight thiol bacillithiol (BSH) on Cu(I)-binding to CopAab was assessed. Dimeric CopAab persisted in the presence of BSH, with previously undetected Cu7(CopAab)2 and Cu6(CopAab)2(BSH) forms apparent

    Think yellow and keep green—Role of sulfanes from garlic in agriculture

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    Reactive sulfur species from garlic have long been renowned for their health benefits and antimicrobial properties. In agriculture the subject matter is now gathering momentum in the search for new bio-pesticides to addressing emerging environmental concerns and tighter restrictions on the use of many conventional chemical pesticides. Although the precise modes of action of these garlic-derived bioactives is complex, recent research has provided a number of new insights that deepen our understanding of garlic-derived products, such as garlic extracts and oils. Herein, their activity against various crop-damaging pests is reviewed. In many cases, there seems to be a broad range of activity associated with the sulfur-containing compounds derived from Allium species, which manifests itself in diverse insecticidal, antifungal, and nematicidal activities. These activities open a new understanding to develop this natural chemistry as a “green pesticide”

    Beyond the plane-parallel and Newtonian approach: Wide-angle redshift distortions and convergence in general relativity

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    We extend previous analyses of wide-angle correlations in the galaxy power spectrum in redshift space to include all general relativistic effects. These general relativistic corrections to the standard approach become important on large scales and at high redshifts, and they lead to new terms in the wide-angle correlations. We show that in principle the new terms can produce corrections of nearly 10 % on Gpc scales over the usual Newtonian approximation. General relativistic corrections will be important for future large-volume surveys such as SKA and Euclid, although the problem of cosmic variance will present a challenge in observing this.Comment: 14 pages, 5 figures; Typo in equation 5 corrected; results unaffecte

    The Evolution of Anti-Bat Sensory Illusions in Moths

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    Prey transmit sensory illusions to redirect predatory strikes, creating a discrepancy between what a predator perceives and reality. We use the acoustic arms race between bats and moths to investigate the evolution and function of a sensory illusion. The spinning hindwing tails of silk moths (Saturniidae) divert bat attack by reflecting sonar to create a misleading echoic target. We characterized geometric morphometrics of moth hindwings across silk moths, mapped these traits onto a new, robust phylogeny, and found that elaborated hindwing structures have converged on four adaptive shape peaks. To test the mechanism underlying these anti-bat traits, we pit bats against three species of silk moths with experimentally altered hindwings that created a representative gradient of ancestral and extant hindwing shapes. High-speed videography of battles reveals that moths with longer hindwings and tails more successfully divert bat attack. We postulate that sensory illusions are widespread and are underappreciated drivers of diversity across systems

    Mental practice with motor imagery in stroke recovery: Randomized controlled trial of efficacy

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    This randomized controlled trial evaluated the therapeutic benefit of mental practice with motor imagery in stroke patients with persistent upper limb motor weakness. There is evidence to suggest that mental rehearsal of movement can produce effects normally attributed to practising the actual movements. Imagining hand movements could stimulate restitution and redistribution of brain activity, which accompanies recovery of hand function, thus resulting in a reduced motor deficit. Current efficacy evidence for mental practice with motor imagery in stroke is insufficient due to methodological limitations. This randomized controlled sequential cohort study included 121 stroke patients with a residual upper limb weakness within 6 months following stroke (on average &lt;3 months post-stroke). Randomization was performed using an automated statistical minimizing procedure. The primary outcome measure was a blinded rating on the Action Research Arm test. The study analysed the outcome of 39 patients involved in 4 weeks of mental rehearsal of upper limb movements during 45-min supervised sessions three times a week and structured independent sessions twice a week, compared to 31 patients who performed equally intensive non-motor mental rehearsal, and 32 patients receiving normal care without additional training. No differences between the treatment groups were found at baseline or outcome on the Action Research Arm Test (ANCOVA statistical P&thinsp;=&thinsp;0.77, and effect size partial &eta;2&thinsp;=&thinsp;0.005) or any of the secondary outcome measures. Results suggest that mental practice with motor imagery does not enhance motor recovery in patients early post-stroke. In light of the evidence, it remains to be seen whether mental practice with motor imagery is a valid rehabilitation technique in its own right

    ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update)

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    This document developed by the International Society for Clinical Electrophysiology of Vision (ISCEV) provides guidance for calibration and verification of stimulus and recording systems specific to clinical electrophysiology of vision. This guideline provides additional information for those using ISCEV Standards and Extended protocols and supersedes earlier Guidelines. The ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update) were approved by the ISCEV Board of Directors 01, March 2023
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