69 research outputs found

    Initial recruitment and establishment of vascular plants in relation to topographical variation in microsite conditions on a recently-deglaciated moraine on Ellesmere Island, high arctic Canada

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    We investigated the effects of topographical positions (moraine ridge, upper side slope and lower side slope) within a recently-deglaciated young moraine on initial recruitment and establishment of vascular plants. Compared with the moraine ridge, the upper slope had similar/higher abundance of vascular plants in terms of percent cover, frequency occurrence, species number, and density/biomass of a dominating species, Salix arctica. Establishment and growth of vascular plants are generally inhibited on unstable habitats; nevertheless, on this newly-formed moraine, every attribute measured for vascular plants implied a higher probability of vascular plant recruitment on the upper slope, where substrate is less stable than on the ridge. Further, the microsite with greater vascular plant abundance, S. arctica density and S. arctica aboveground/leaf biomass accumulated more organic materials regardless of topographical positions, and such an organic accumulation was deepest on the upper slope, suggesting that relatively-successful plant establishment occurs on this site. This is further supported by the S. arctica population structure, which implies a relatively-constant juvenile supply on the upper slope. Along a slope, unstable gravels easily slide down hill. This topographical process may cause large rock size and high surface cover by rocks on the lower slope. On the upper slope, the percent cover by rocks had therefore become smaller, leading to high cover by fine-grained sediments, which retain moisture favorable for germination and growth of vascular plants. This would enhance the emergence of pioneer vascular plant species, probably resulting in higher vascular plant abundance, density and biomass of S. arctica on the upper slope. This study suggests that during primary succession following deglaciation in the high arctic the upper slope of a newly-formed glacier moraine may be an important location for the initial recruitment and establishment of pioneer vascular plant species, such as S. arctica

    Measuring the Complexity of Consciousness

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    The quest for a scientific description of consciousness has given rise to new theoretical and empirical paradigms for the investigation of phenomenological contents as well as clinical disorders of consciousness. An outstanding challenge in the field is to develop measures that uniquely quantify global brain states tied to consciousness. In particular, information-theoretic complexity measures such as integrated information have recently been proposed as measures of conscious awareness. This suggests a new framework to quantitatively classify states of consciousness. However, it has proven increasingly difficult to apply these complexity measures to realistic brain networks. In part, this is due to high computational costs incurred when implementing these measures on realistically large network dimensions. Nonetheless, complexity measures for quantifying states of consciousness are important for assisting clinical diagnosis and therapy. This article is meant to serve as a lookup table of measures of consciousness, with particular emphasis on clinical applicability of these measures. We consider both, principle-based complexity measures as well as empirical measures tested on patients. We address challenges facing these measures with regard to realistic brain networks, and where necessary, suggest possible resolutions.Comment: 9 page

    Panretinal Photocoagulation Using Short-Pulse Laser Induces Less Inflammation and Macular Thickening in Patients with Diabetic Retinopathy

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    We compared the effect of panretinal photocoagulation (PRP) using short-pulse laser (SPL) and conventional laser, regardless of the number of spots, in terms of their effect on the progression of diabetic macular edema (DME) and anterior flare intensity (AFI) in patients with high-risk nonproliferative diabetic retinopathy (non-PDR). Forty-two eyes of 42 patients were subjected to PRP using the conventional argon laser (Conv group) or SPL (SPL group). CRT and AFI levels in the SPL group were significantly lower than those in the Conv group (CRT at 4, 6, and 10 weeks; AFI at 6, 10, and 18 weeks). Eyes of rabbits were photocoagulated using conventional laser with 500 spots (Conv 500s), SPL with 500 spots (SPL 500s), or 1000 spots (SPL 1000s). Vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), and monocyte chemotactic protein-1 (MCP-1) levels in vitreous humor were measured using an immunoassay. Compared to conventional laser, VEGF, IL-6, and MCP-1 levels were significantly lower in the SPL 1000s and SPL 500s groups. In patients with high-risk non-PDR, SPL has a greater preventive effect on the progression of DME and AFI and produces less inflammatory cytokines than conventional lasers

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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