230 research outputs found

    Biophysical assessment of reefs in Keppel Bay: a baseline study (April 2007)

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    The Keppel Islands are a group of 16 continental islands lying 18 km off the coastal town of Yeppoon in the southern Great Barrier Reef. Located in the shallow basin to the north of Keppel Bay, the islands are host to a patchwork of fringing reefs in various forms of development. Coral communities are abundant in some locations, and coral cover is high (60 to 70%) relative to the average at sites surveyed by the Australian Institute of Marine Science’s Long-Term Monitoring Program (~35%), and are often dominated by extensive stands of branching Acropora that extend into shallow water. These ‘staghorn’ corals are vulnerable to impacts caused by environmental stresses such as elevated sea temperature (causing coral bleaching events), degraded water quality (associated with hyposaline floods events) and physical damage (from cyclones, storms and anchoring). The Fitzroy River, one of the largest catchments in Queensland, is about 40 km to the south of the Keppel Islands. Large flood plumes occur approximately every 10 years, and the soft riverine sediments are regularly re-suspended in the shallow bay by wind and tide action causing high turbidity. Heavy rainfall also affects the shallow reef flat habitats, with reported incidences of coral mortality caused by heavy rain at times of extreme low tidesID: 176

    The two-dimensional random-bond Ising model, free fermions and the network model

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    We develop a recently-proposed mapping of the two-dimensional Ising model with random exchange (RBIM), via the transfer matrix, to a network model for a disordered system of non-interacting fermions. The RBIM transforms in this way to a localisation problem belonging to one of a set of non-standard symmetry classes, known as class D; the transition between paramagnet and ferromagnet is equivalent to a delocalisation transition between an insulator and a quantum Hall conductor. We establish the mapping as an exact and efficient tool for numerical analysis: using it, the computational effort required to study a system of width MM is proportional to M3M^{3}, and not exponential in MM as with conventional algorithms. We show how the approach may be used to calculate for the RBIM: the free energy; typical correlation lengths in quasi-one dimension for both the spin and the disorder operators; even powers of spin-spin correlation functions and their disorder-averages. We examine in detail the square-lattice, nearest-neighbour ±J\pm J RBIM, in which bonds are independently antiferromagnetic with probability pp, and ferromagnetic with probability 1−p1-p. Studying temperatures T≄0.4JT\geq 0.4J, we obtain precise coordinates in the p−Tp-T plane for points on the phase boundary between ferromagnet and paramagnet, and for the multicritical (Nishimori) point. We demonstrate scaling flow towards the pure Ising fixed point at small pp, and determine critical exponents at the multicritical point.Comment: 20 pages, 25 figures, figures correcte

    Physical fitness in people with a spinal cord injury: the association with complications and duration of rehabilitation.

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    Objective: To assess the association between physical fitness and its recovery over time on the one hand, and complications and duration of phases of rehabilitation on the other. Design and setting: Prospective cohort study at eight rehabilitation centres. Subjects: People with a spinal cord injury were assessed four times: at the start of active rehabilitation (n = 110), three months later (n = 92), at discharge (n = 137) and a year after discharge from inpatient rehabilitation (n = 91). Main measures: Physical fitness was defined as aerobic capacity, determined at each occasion by the peak oxygen uptake (peak V

    Mitochondrial localization and function of a subset of 22q11 deletion syndrome candidate genes

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    Six genes in the 1.5 MB region of chromosome 22 deleted in DiGeorge/22q11 Deletion Syndrome—Mrpl40, Prodh, Slc25a1, Txnrd2, T10, and Zdhhc8—encode mitochondrial proteins. All six genes are expressed in the brain, and maximal expression coincides with peak forebrain synaptogenesis shortly after birth. Furthermore, their protein products are associated with brain mitochondria, including those in synaptic terminals. Among the six, only Zddhc8 influences mitochondria-regulated apoptosis when overexpressed, and appears to interact biochemically with established mitochondrial proteins. Zdhhc8 has an apparent interaction with Uqcrc1, a component of mitochondrial complex III. The two proteins are coincidently expressed in presynaptic processes; however, Zdhhc8 is more frequently seen in glutamatergic terminals. 22q11 deletion may alter metabolic properties of cortical mitochondria during early post-natal life, since expression complex III components, including Uqcrc1, is significantly increased at birth in a mouse model of 22q11 deletion, and declines to normal values in adulthood. Our results suggest that altered dosage of one, or several 22q11 mitochondrial genes, particularly during early postnatal cortical development, may disrupt neuronal metabolism or synaptic signaling

    The impact of introducing alcohol‐free beer options in bars and public houses on alcohol sales and revenue: a randomised crossover field trial

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    Aims: The study aimed to estimate the impact of introducing a draught alcohol‐free beer, thereby increasing the relative availability of these products, on alcohol sales and monetary takings in bars and pubs in England. Design: Randomised crossover field trial. Setting: England. Participants: Fourteen venues that did not previously sell draught alcohol‐free beer. Intervention and comparator: Venues completed two intervention periods and two control periods in a randomised order over 8 weeks. Intervention periods involved replacing one draught alcoholic beer with an alcohol‐free beer. Control periods operated business as usual. Measurements: The primary outcome was mean weekly volume (in litres) of draught alcoholic beer sold. The secondary outcome was mean weekly revenue [in GBP (£)] from all drinks. Analyses adjusted for randomised order, special events, season and busyness. Findings: The adjusted mean difference in weekly sales of draught alcoholic beer was −20 L [95% confidence interval (CI) = −41 to +0.4], equivalent to a 4% reduction (95% CI = 8% reduction to 0.1% increase) in the volume of alcoholic draught beer sold when draught alcohol‐free beer was available. Excluding venues that failed at least one fidelity check resulted in an adjusted mean difference of −29 L per week (95% CI = −53 to −5), equivalent to a 5% reduction (95% CI = 8% reduction to 0.8% reduction). The adjusted mean difference in weekly revenue was +61 GBP per week (95% CI = −328 to +450), equivalent to a 1% increase (95% CI = 5% decrease to 7% increase) when draught alcohol‐free beer was available. Conclusions: Introducing a draught alcohol‐free beer in bars and pubs in England reduced the volume of draught alcoholic beer sold by 4% to 5%, with no evidence of the intervention impacting net revenue

    Analytical Results for Individual and Group Selection of Any Intensity

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    The idea of evolutionary game theory is to relate the payoff of a game to reproductive success (= fitness). An underlying assumption in most models is that fitness is a linear function of the payoff. For stochastic evolutionary dynamics in finite populations, this leads to analytical results in the limit of weak selection, where the game has a small effect on overall fitness. But this linear function makes the analysis of strong selection difficult. Here, we show that analytical results can be obtained for any intensity of selection, if fitness is defined as an exponential function of payoff. This approach also works for group selection (= multi-level selection). We discuss the difference between our approach and that of inclusive fitness theory

    Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

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    The Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction is measured in a data sample corresponding to 0.41fb−1fb^{-1} of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2ÎČ\beta measurement from B0→J/ψKS0B^0\to J/\psi K_S^0 The time-integrated branching fraction is measured to be BF(Bs0→J/ψKS0)=(1.83±0.28)×10−5BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}. This is the most precise measurement to date
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