909 research outputs found

    Global ecological success of Thalassoma fishes in extreme coral reef habitats

    Get PDF
    Phenotypic adaptations can allow organisms to relax abiotic selection and facilitate their ecological success in challenging habitats, yet we have relatively little data for the prevalence of this phenomenon at macroecological scales. Using data on the relative abundance of coral reef wrasses and parrotfishes (f. Labridae) spread across three ocean basins and the Red Sea, we reveal the consistent global dominance of extreme wave-swept habitats by fishes in the genus Thalassoma, with abundances up to 15 times higher than any other labrid. A key locomotor modification-a winged pectoral fin that facilitates efficient underwater flight in high-flow environments-is likely to have underpinned this global success, as numerical dominance by Thalassoma was contingent upon the presence of high-intensity wave energy. The ecological success of the most abundant species also varied with species richness and the presence of congeneric competitors. While several fish taxa have independently evolved winged pectoral fins, Thalassoma appears to have combined efficient high-speed swimming (to relax abiotic selection) with trophic versatility (to maximize exploitation of rich resources) to exploit and dominate extreme coral reef habitats around the world

    Will fish be part of future healthy and sustainable diets?

    Get PDF
    First paragraph: The adoption of healthy and sustainable diets and food systems is recognised as a means to address the global challenge of malnutrition and poor-quality diets, and unprecedented environmental damage from food production and consumption.1 Sustainable diets have also been recognised as a key strategy to achieve the Sustainable Development Goals. Reducing consumption of animal-source foods is frequently presented as key to improving the sustainability of food systems.2 Fish and seafood can have a lower environmental impact and in many cases are considered more efficient than terrestrial animal production (albeit with wide variation) depending on the type of production or capture method,3 yet remain largely absent, or insufficiently articulated in the sustainable diets literature, rendering their future role in healthy diets unclear.4 This absence of specific consideration of fish and seafood extends to food security literature, in which the role of fish remains under-recognised and undervalued.5 Legitimate concerns exist regarding the environmental sustainability of fisheries and aquaculture systems; however, we argue that an overemphasis on the so-called doomsday portrayal of fish—which often dominates literature and the broader media—masks the myriad of positive contributions of the fisheries sector to nutrition and sustainability and limits its scope in contributing to healthy and sustainable food systems

    Economic Impact and Social Benefits Study of Coldwater Angling in Minnesota

    Get PDF
    Saint Paul: University of Minnesota Extension Service, Tourism Center.This study was conducted of anglers utilizing Minnesota’s northeast region cold-water fisheries in 2000-2001, and was based upon a staged mail-back questionnaire sent to anglers who had purchased a trout/salmon stamp from the Minnesota DNR. The purpose of this study was to investigate the economic and social benefits of coldwater angling participation in the state of Minnesota. Overall 10,297 questionnaires were mailed, and 3,029 returned for a response rate of 33%. Two null hypotheses guided this study: 1. There are no expenditure differences between the different types of coldwater angling investigated. 2. There are no experience differences between the different types of coldwater anglers. The survey looked at access points; bait used; species preferences; preference for fishing location; angler age, gender and education; trip distance; purpose of anglers’ trips; and numerous other behaviors and preferences. It also assessed the economic impact of anglers on local economies. The report notes that “fishing equipment was the largest expenditure in preparation for the trip (12.57/person/day).Totalexpendituresathomewere12.57/person/day). Total expenditures at home were 33.90 per person per day. The largest expenses en route and onsite were lodging (15.39/person/day),preparedfood(15.39/person/day), prepared food (12.55/person/day), and gas (12.70/person/day)totaling12.70/person/day) totaling 71.31 per person daily. In sum, the typical coldwater angler spent $105.21/day. Overall, anglers were satisfied with their trip, and the quality, size and number of fish caught. The study concludes with the following findings: “There were many differences noted between the five different types of fishing investigated in this study. The differences were substantial, significant, and revealing. The evidence presented strongly argues for rejecting both of the null hypotheses used to guide this research. Therefore, we can state with a high degree of certainty that expenditure differences do exist for anglers between the different types of coldwater angling and that different experiences are sought by anglers engaging in different types of fishing. The research that allowed us to reject both null hypotheses also provides us with some interesting insights into other differences between anglers in the five different fishing types.

    The KELT Follow-up Network and Transit False-positive Catalog: Pre-vetted False Positives for TESS

    Get PDF
    The Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey of transiting planets orbiting bright stars for over 10 years. The KELT images have a pixel scale of ~23'' pixel^(−1)—very similar to that of NASA's Transiting Exoplanet Survey Satellite (TESS)—as well as a large point-spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3'. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with spatial resolution, cadence, and photometric precision higher than the KELT telescopes, as well as spectroscopic observations of the candidate host stars. The KELT-FUN team has followed-up over 1600 planet candidates since 2011, resulting in more than 20 planet discoveries. Excluding ~450 false alarms of non-astrophysical origin (i.e., instrumental noise or systematics), we present an all-sky catalog of the 1128 bright stars (6 < V < 13) that show transit-like features in the KELT light curves, but which were subsequently determined to be astrophysical false positives (FPs) after photometric and/or spectroscopic follow-up observations. The KELT-FUN team continues to pursue KELT and other planet candidates and will eventually follow up certain classes of TESS candidates. The KELT FP catalog will help minimize the duplication of follow-up observations by current and future transit surveys such as TESS

    Non-perturbative dynamics of hot non-Abelian gauge fields: beyond leading log approximation

    Get PDF
    Many aspects of high-temperature gauge theories, such as the electroweak baryon number violation rate, color conductivity, and the hard gluon damping rate, have previously been understood only at leading logarithmic order (that is, neglecting effects suppressed only by an inverse logarithm of the gauge coupling). We discuss how to systematically go beyond leading logarithmic order in the analysis of physical quantities. Specifically, we extend to next-to-leading-log order (NLLO) the simple leading-log effective theory due to Bodeker that describes non-perturbative color physics in hot non-Abelian plasmas. A suitable scaling analysis is used to show that no new operators enter the effective theory at next-to-leading-log order. However, a NLLO calculation of the color conductivity is required, and we report the resulting value. Our NLLO result for the color conductivity can be trivially combined with previous numerical work by G. Moore to yield a NLLO result for the hot electroweak baryon number violation rate.Comment: 20 pages, 1 figur
    • …
    corecore