1,946 research outputs found

    The ebb and flow of adaptive co-management: a longitudinal evaluation of a conservation conflict

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    Adaptive co-management (ACM) is an emerging approach to the governance of social-ecological systems, but there are few long-term assessments of its efficacy. This is especially true in conservation conflicts, where ACM can mitigate disputes between polarised stakeholders. We evaluated ACM that emerged in 2005 to address conflict between seal conservation and fisheries interests in the Moray Firth, Scotland. We interviewed 20 stakeholders in 2015, repeating a survey carried out in 2011 which applied an indicator framework to measure outcomes and pre-conditions for ACM to continue. In 2015, all but one of the 12 outcome indicators were positive, the exception being the conservation status of salmon. However, pre-conditions for ACM’s continuation had weakened, with declines between 2005, 2011 and 2015. These were most marked for three indicators: leaders prepared to champion the process, presence of a bridging organisation or individual, and participation of all impacted stakeholders. The results show that ACM in this conservation conflict is dynamic. Perceived declines in salmon abundance and increases in seal numbers have renewed tensions amongst stakeholders, triggering a ‘revival’ phase of ACM initiated by fishery interests. Our study provides empirical evidence of ACM’s fluid nature, and how resource crises can reignite ACM. We suggest that participatory evaluation is a potentially important early-warning mechanism that can identify remedial action and galvanise stakeholders to respond to the re-emergence of conflict

    Cryptic photosynthesis, Extrasolar planetary oxygen without a surface biological signature

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    On the Earth, photosynthetic organisms are responsible for the production of virtually all of the oxygen in the atmosphere. On the land, vegetation reflects in the visible, leading to a red edge that developed about 450 Myr ago and has been proposed as a biosignature for life on extrasolar planets. However, in many regions of the Earth, and particularly where surface conditions are extreme, for example in hot and cold deserts, photosynthetic organisms can be driven into and under substrates where light is still sufficient for photosynthesis. These communities exhibit no detectable surface spectral signature to indicate life. The same is true of the assemblages of photosynthetic organisms at more than a few metres depth in water bodies. These communities are widespread and dominate local photosynthetic productivity. We review known cryptic photosynthetic communities and their productivity. We link geomicrobiology with observational astronomy by calculating the disk-averaged spectra of cryptic habitats and identifying detectable features on an exoplanet dominated by such a biota. The hypothetical cryptic photosynthesis worlds discussed here are Earth-analogs that show detectable atmospheric biomarkers like our own planet, but do not exhibit a discernable biological surface feature in the disc-averaged spectrum.Comment: 23 pages, 2 figures, Astrobiology (TBP) - updated Table 1, typo in detectable O2 correcte

    Representations of integers by certain positive definite binary quadratic forms

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    We prove part of a conjecture of Borwein and Choi concerning an estimate on the square of the number of solutions to n=x^2+Ny^2 for a squarefree integer N.Comment: 8 pages, submitte

    Kinetics and products of the IO + BrO reaction

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    Optical Imaging and Spectroscopic Observation of the Galactic Supernova Remnant G85.9-0.6

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    Optical CCD imaging with Hα\alpha and [SII] filters and spectroscopic observations of the galactic supernova remnant G85.9-0.6 have been performed for the first time. The CCD image data are taken with the 1.5m Russian-Turkish Telescope (RTT150) at TUBITAK National Observatory (TUG) and spectral data are taken with the Bok 2.3 m telescope on Kitt Peak, AZ. The images are taken with narrow-band interference filters Hα\alpha, [SII] and their continuum. [SII]/Hα\alpha ratio image is performed. The ratio obtained from [SII]/Hα\alpha is found to be \sim0.42, indicating that the remnant interacts with HII regions. G85.9-0.6 shows diffuse-shell morphology. [SII]λλ6716/6731\lambda\lambda 6716/6731 average flux ratio is calculated from the spectra, and the electron density NeN_{e} is obtained to be 395 cm3cm^{-3}. From [OIII]/Hβ\beta ratio, shock velocity has been estimated, pre-shock density of nc=14n_{c}=14 cm3cm^{-3}, explosion energy of E=9.2×1050E=9.2\times10^{50} ergs, interstellar extinction of E(BV)=0.28E(B-V)=0.28, and neutral hydrogen column density of N(HI)=1.53×1021N(HI)=1.53\times10^{21} cm2cm^{-2} are reported.Comment: 20 pages, 4 tables, 4 figures. Accepted for publication in Astrophysics & Space Scienc

    The 2-Channel Kondo Model I: Review of Experimental Evidence for its Realization in Metal Nanoconstrictions

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    Certain zero-bias anomalies (ZBAs) in the voltage, temperature and magnetic field dependence of the conductance G(V,T,H)G(V,T,H) of quenched Cu point contacts have previously been interpreted to be due to non-magnetic 2-channel Kondo (2CK) scattering from near-degenerate atomic two-level tunneling systems (Ralph and Buhrman, 1992; Ralph et al. 1994), and hence to represent an experimental realization of the non-Fermi-liquid physics of the T=0 fixed point of the 2-channel Kondo model. In this, the first in a series of three papers (I,II,III) devoted to 2-channel Kondo physics, we present a comprehensive review of the quenched Cu ZBA experiments and their 2CK interpretation, including new results on ZBAs in constrictions made from Ti or from metallic glasses. We first review the evidence that the ZBAs are due to electron scattering from stuctural defects that are not static, but possess internal dynamics. In order to distinguish between several mechanisms proposed to explain the experiments, we then analyze the scaling properties of the conductance at low temperature and voltage and extract from the data a universal scaling function Γ(v)\Gamma(v). The theoretical calculation of the corresponding scaling function within the 2CK model is the subject of papers II and III. The main conclusion of our work is that the properties of the ZBAs, and most notably their scaling behavior, are in good agreement with the 2CK model and clearly different from several other proposed mechanisms.Comment: 35 pages RevTeX, 19 encapsulated postscript figures; this final published version features two additional authors, an additional section reviewing recent experiments on Ti nanoconstrictions that agree very well with the 2-channel Kondo model, 6 new figures (and is much shorter the previous 53 page version, due to reformatting

    Leading strategies in competitive on-line prediction

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    We start from a simple asymptotic result for the problem of on-line regression with the quadratic loss function: the class of continuous limited-memory prediction strategies admits a "leading prediction strategy", which not only asymptotically performs at least as well as any continuous limited-memory strategy but also satisfies the property that the excess loss of any continuous limited-memory strategy is determined by how closely it imitates the leading strategy. More specifically, for any class of prediction strategies constituting a reproducing kernel Hilbert space we construct a leading strategy, in the sense that the loss of any prediction strategy whose norm is not too large is determined by how closely it imitates the leading strategy. This result is extended to the loss functions given by Bregman divergences and by strictly proper scoring rules.Comment: 20 pages; a conference version is to appear in the ALT'2006 proceeding

    Snow-sourced bromine and its implications for polar tropospheric ozone

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    In the last two decades, significant depletion of boundary layer ozone (ozone depletion events, ODEs) has been observed in both Arctic and Antarctic spring. ODEs are attributed to catalytic destruction by bromine radicals (Br plus BrO), especially during bromine explosion events (BEs), when high concentrations of BrO periodically occur. However, neither the exact source of bromine nor the mechanism for sustaining the observed high BrO concentrations is completely understood. Here, by considering the production of sea salt aerosol from snow lying on sea ice during blowing snow events and the subsequent release of bromine, we successfully simulate the BEs using a global chemistry transport model. We find that heterogeneous reactions play an important role in sustaining a high fraction of the total inorganic bromine as BrO. We also find that emissions of bromine associated with blowing snow contribute significantly to BrO at mid-latitudes. Modeled tropospheric BrO columns generally compare well with the tropospheric BrO columns retrieved from the GOME satellite instrument (Global Ozone Monitoring Experiment). The additional blowing snow bromine source, identified here, reduces modeled high latitude lower tropospheric ozone amounts by up to an average 8% in polar spring

    P-Wave Charmonium Production in B-Meson Decays

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    We calculate the decay rates of BB mesons into P-wave charmonium states using new factorization formulas that are valid to leading order in the relative velocity of the charmed quark and antiquark and to all orders in the running coupling constant of QCD. We express the production rates for all four P states in terms of two nonperturbative parameters, the derivative of the wavefunction at the origin and another parameter related to the probability for a charmed-quark-antiquark pair in a color-octet S-wave state to radiate a soft gluon and form a P-wave bound state. Using existing data on BB meson decays into χc1\chi_{c1} to estimate the color-octet parameter, we find that the color-octet mechanism may account for a significant fraction of the χc1\chi_{c1} production rate and that BB mesons should decay into χc2\chi_{c2} at a similar rate.Comment: 14 page
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