2,363 research outputs found

    Sedimentation between the Herbert delta and the Palm Isles, Halifax Bay, Central Great Barrier Reef

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    [Extract from the 1985 report] This report describes sedimentary facies in Halifax Bay, a small area of inner shelf in the Central Great Barrier Reef Province. The area is semi-protected, primarily by the Great Barrier Reef itself and secondarily by a group of nearshore continental islands, the Palm Isles. The main sedimentary facies are modern terrigenous sand and mud along the coast of the Herbert Delta, and mixed modern-palimpsest muddy sand and gravel in the central Bay. Carbonate content increases towards the islands where there are fringing reefs. The main aims of this report are: 1. to detail the configuration of the embayment and the nature of sediments, both in the Bay and in the fringing reefs, 2. to investigate the nature of terrigenous sediments being deposited on the fringing reefs, and whether the amounts of sediment have changed during the Holocene, and 3. to outline a model of sedimentation for the area

    Sedimentary framework of mainland fringing reef development, Cape Tribulation Area

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    Mainland fringing reefs with a diverse coral fauna have developed in the Cape Tribulation area primarily upon coastal sediment bodies such as beach shoals and creek mouth bars. Growth on steep rocky headlands is minor. The reefs have extensive sandy beaches to landward, and an irregular outer margin. Typically there is a raised platform of dead nef along the outer edge of the reef, and dead coral columns lie buried under the reef flat. Live coral growth is restricted to the outer reef slope. Seaward of the reefs is a narrow wedge of muddy, terrigenous sediment, which thins offshore. Beach, reef and inner shelf sediments all contain 50% terrigenous material, indicating the reefs have always grown under conditions of heavy terrigenous influx. The relatively shallow lower limit of coral growth (ca 6m below ADD) is typical of reef growth in turbid waters, where decreased light levels inhibit coral growth. Radiocarbon dating of material from surveyed sites confirms the age of the fossil coral columns as 33304110 ybp, indicating that they grew during the late postglacial sea-level high (ca 5500-6500 ybp). The former thriving reef-flat was killed by a post-5500 ybp sea-level fall of ca 1 m. Although this study has not assessed the community structure of the fringing reefs, nor whether changes are presently occurring, it is clear the corals present today on the fore-reef slope have always lived under heavy terrigenous influence, and that the fossil reef-flat can be explained as due to the mid-Holocene fall in sea-level. A medium term programme is required to record sediment loading and coral community structure, and to establish the environmental vulnerability of these reefs

    Relative value of ruminally degradable and undegradable protein on the utilization of low-quality prairie hay by steers

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    An experiment was performed to investigate the impact of providing six levels of ruminally degradable protein (RDP; protein that is available to ruminal microbes) in combination with two levels of ruminally undegradable protein (RUP; protein that is not available to the ruminal microbes, but can be digested directly by cattle) on the intake and digestion of low-quality prairie hay. Twelve steers were provided unlimited access to low-quality prairie hay (5.3% crude protein and 71.7% neutral detergent fiber) throughout the trial. To simulate dietary RUP, casein was infused abomasally once daily at either 0 or 0.087% of body weight. To simulate dietary RDP, casein was infused ruminally once daily at 0, 0.029, 0.058, 0.087, 0.116, or 0.145% of body weight. As provision of RDP increased, forage intake and fiber digestion increased. Supplementing with RUP alone increased forage intake but not fiber digestion, although the intake response was not as large as providing the same amount of RDP. In conclusion, RUP is less efficient than RDP in stimulating forage intake and digestion

    The impact of near-term climate policy choices on technology and emission transition pathways

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    This paper explores the implications of delays (to 2030) in implementing optimal policies for long-term transition pathways to limit climate forcing to 450 ppm CO2e on the basis of the AMPERE Work Package 2 model comparison study. The paper highlights the critical importance of the period 2030-2050 for ambitious mitigation strategies. In this period, the most rapid shift to low greenhouse gas emitting technology occurs. In the delayed response emission mitigation scenarios, an even faster transition rate in this period is required to compensate for the additional emissions before 2030. Our physical deployment measures indicate that the availability of CCS technology could play a critical role in facilitating the attainment of ambitious mitigation goals. Without CCS, deployment of other mitigation technologies would become extremely high in the 2030-2050 period. Yet the presence of CCS greatly alleviates the challenges to the transition particularly after the delayed climate policies, lowering the risk that the long-term goal becomes unattainable. The results also highlight the important role of bioenergy with CO2 capture and storage (BECCS), which facilitates energy production with negative carbon emissions. If BECCS is available, transition pathways exceed the emission budget in the mid-term, removing the excess with BECCS in the long term. Excluding either BE or CCS from the technology portfolio implies that emission reductions need to take place much earlier

    Finding purpose in the conservation of biodiversity by the commingling of science and ethics

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    Averting the biodiversity crisis requires closing a gap between how humans tend to behave, individually and collectively, and how we ought to behave—“ought to” in the sense of behaviors required to avert the biodiversity crisis. Closing that gap requires synthesizing insight from ethics with insights from social and behavioral sciences. This article contributes to that synthesis, which presents in several provocative hypotheses: (i) Lessening the biodiversity crisis requires promoting pro-conservation behavior among humans. Doing so requires better scientific understanding of how one’s sense of purpose in life affects conservation-relevant behaviors. Psychology and virtue-focused ethics indicate that behavior is importantly influenced by one’s purpose. However, conservation psychology has neglected inquiries on (a) the influence of one’s purpose (both the content and strength of one’s purpose) on conservation-related behaviors and (b) how to foster proconservation purposes; (ii) lessening the biodiversity crisis requires governance—the regulation of behavior by governments, markets or other organization through various means, including laws, norms, and power—to explicitly take conservation as one of its fundamental purposes and to do so across scales of human behaviors, from local communities to nations and corporations; (iii) lessening the biodiversity crisis requires intervention via governance to nudge human behavior in line with the purpose of conservation without undue infringement on other basic values. Aligning human behavior with conservation is inhibited by the underlying purpose of conservation being un derspecified. Adequate specification of conservation’s purpose will require additional interdisciplinary research involving insights from ethics, social and behavioral sciences, and conservation biology

    Louse (Insecta : Phthiraptera) mitochondrial 12S rRNA secondary structure is highly variable

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    Lice are ectoparasitic insects hosted by birds and mammals. Mitochondrial 12S rRNA sequences obtained from lice show considerable length variation and are very difficult to align. We show that the louse 12S rRNA domain III secondary structure displays considerable variation compared to other insects, in both the shape and number of stems and loops. Phylogenetic trees constructed from tree edit distances between louse 12S rRNA structures do not closely resemble trees constructed from sequence data, suggesting that at least some of this structural variation has arisen independently in different louse lineages. Taken together with previous work on mitochondrial gene order and elevated rates of substitution in louse mitochondrial sequences, the structural variation in louse 12S rRNA confirms the highly distinctive nature of molecular evolution in these insects

    Worst case and probabilistic analysis of the 2-Opt algorithm for the TSP

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    2-Opt is probably the most basic local search heuristic for the TSP. This heuristic achieves amazingly good results on “real world” Euclidean instances both with respect to running time and approximation ratio. There are numerous experimental studies on the performance of 2-Opt. However, the theoretical knowledge about this heuristic is still very limited. Not even its worst case running time on 2-dimensional Euclidean instances was known so far. We clarify this issue by presenting, for every p∈N , a family of L p instances on which 2-Opt can take an exponential number of steps. Previous probabilistic analyses were restricted to instances in which n points are placed uniformly at random in the unit square [0,1]2, where it was shown that the expected number of steps is bounded by O~(n10) for Euclidean instances. We consider a more advanced model of probabilistic instances in which the points can be placed independently according to general distributions on [0,1] d , for an arbitrary d≥2. In particular, we allow different distributions for different points. We study the expected number of local improvements in terms of the number n of points and the maximal density ϕ of the probability distributions. We show an upper bound on the expected length of any 2-Opt improvement path of O~(n4+1/3⋅ϕ8/3) . When starting with an initial tour computed by an insertion heuristic, the upper bound on the expected number of steps improves even to O~(n4+1/3−1/d⋅ϕ8/3) . If the distances are measured according to the Manhattan metric, then the expected number of steps is bounded by O~(n4−1/d⋅ϕ) . In addition, we prove an upper bound of O(ϕ√d) on the expected approximation factor with respect to all L p metrics. Let us remark that our probabilistic analysis covers as special cases the uniform input model with ϕ=1 and a smoothed analysis with Gaussian perturbations of standard deviation σ with ϕ∼1/σ d

    Fractional Exclusion Statistics and Anyons

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    Do anyons, dynamically realized by the field theoretic Chern-Simons construction, obey fractional exclusion statistics? We find that they do if the statistical interaction between anyons and anti-anyons is taken into account. For this anyon model, we show perturbatively that the exchange statistical parameter of anyons is equal to the exclusion statistical parameter. We obtain the same result by applying the relation between the exclusion statistical parameter and the second virial coefficient in the non-relativistic limit.Comment: 9 pages, latex, IFT-498-UN

    Mobile apps for weight management: a review of the latest evidence to inform practice

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    Over the last decade, mobile technology has emerged as a potentially useful platform to facilitate weight management and tackle the current obesity epidemic. Clinicians are being more frequently asked to give advice about the usefulness of mobile apps and many individuals have already integrated apps into their attempts to manage weight. Hence, it is imperative for clinicians involved in weight management to be aware of the latest developments and knowledge about available mobile apps and their usefulness in this field. A number of newly published studies have demonstrated promising results of mobile-based interventions for weight management across different populations, but the extent of their effectiveness remains widely debated. This narrative literature review synthesizes the latest evidence, primarily from randomized controlled trials (RCTs), regarding the clinical use of mobile applications for weight management, as well as highlight key limitations associated with their use and directions for future research and practice. Overall, evidence suggests that mobile applications may be useful as low-intensity approaches or adjuncts to conventional weight management strategies. However, there is insufficient evidence to support their use as stand-alone intensive approaches to weight management. Further research is needed to clarify the extent of utility of these applications, as well as the measures required to maximize their potential both as stand-alone approaches and adjuncts to more intensive programs.Drishti P. Ghelani, Lisa J. Moran, Cameron Johnson, Aya Mousa and Negar Naderpoo

    Locked into Copenhagen pledges - Implications of short-term emission targets for the cost and feasibility of long-term climate goals

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    This paper provides an overview of the AMPERE modeling comparison project with focus on the implications of near-term policies for the costs and attainability of long-term climate objectives. Nine modeling teams participated in the project to explore the consequences of global emissions following the proposed policy stringency of the national pledges from the Copenhagen Accord and Cancun Agreements to 2030. Specific features compared to earlier assessments are the explicit consideration of near-term 2030 emission targets as well as the systematic sensitivity analysis for the availability and potential of mitigation technologies. Our estimates show that a 2030 mitigation effort comparable to the pledges would result in a further "lock-in" of the energy system into fossil fuels and thus impede the required energy transformation to reach low greenhouse-gas stabilization levels (450 ppm CO2e). Major implications include significant increases in mitigation costs, increased risk that low stabilization targets become unattainable, and reduced chances of staying below the proposed temperature change target of 2 degrees C in case of overshoot. With respect to technologies, we find that following the pledge pathways to 2030 would narrow policy choices, and increases the risks that some currently optional technologies, such as carbon capture and storage (CCS) or the large-scale deployment of bioenergy, will become "a must" by 2030
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