9 research outputs found

    The Effect of Carbon Credits on Savanna Land Management and Priorities for Biodiversity Conservation

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    Carbon finance offers the potential to change land management and conservation planning priorities. We develop a novel approach to planning for improved land management to conserve biodiversity while utilizing potential revenue from carbon biosequestration. We apply our approach in northern Australia's tropical savanna, a region of global significance for biodiversity and carbon storage, both of which are threatened by current fire and grazing regimes. Our approach aims to identify priority locations for protecting species and vegetation communities by retaining existing vegetation and managing fire and grazing regimes at a minimum cost. We explore the impact of accounting for potential carbon revenue (using a carbon price of US14pertonneofcarbondioxideequivalent)onpriorityareasforconservationandtheimpactofexplicitlyprotectingcarbonstocksinadditiontobiodiversity.OurresultsshowthatimprovedmanagementcanpotentiallyraiseapproximatelyUS14 per tonne of carbon dioxide equivalent) on priority areas for conservation and the impact of explicitly protecting carbon stocks in addition to biodiversity. Our results show that improved management can potentially raise approximately US5 per hectare per year in carbon revenue and prevent the release of 1–2 billion tonnes of carbon dioxide equivalent over approximately 90 years. This revenue could be used to reduce the costs of improved land management by three quarters or double the number of biodiversity targets achieved and meet carbon storage targets for the same cost. These results are based on generalised cost and carbon data; more comprehensive applications will rely on fine scale, site-specific data and a supportive policy environment. Our research illustrates that the duel objective of conserving biodiversity and reducing the release of greenhouse gases offers important opportunities for cost-effective land management investments

    Sexual Dimorphism in Newborn Vertebrae and Its Potential Implications

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    OBJECTIVE: To examine whether the sex-related differences in vertebral cross-sectional area (CSA) found in children and at the timing of peak bone mass – a major determinant of osteoporosis and future fracture risk – are also present at birth. STUDY DESIGN: Vertebral CSA, vertebral height, and intervertebral disc height were measured using magnetic resonance imaging (MRI) in 70 healthy full-term newborns (35 male and 35 female). Additionally, measures of the length and CSA of the humerus, musculature, and adiposity were obtained. RESULTS: Weight, body length, and head and waist circumferences did not significantly differ between sexes (all P’s ≄ 0.06). Compared with newborn boys, girls had significantly smaller vertebral cross-sectional dimensions; 1.47 ± 0.11 vs. 1.31 ± 0.12; P < 0.0001. Multiple linear regression analysis indicated that sex was a predictor of vertebral CSA independent of gestational age, birth weight, and body length. In contrast, sexes were monomorphic with regard to vertebral height, intervertebral disc height, and spinal length (all P’s ≄ 0.11). There were also no sex differences in the length or cross-sectional dimensions of the humerus or in measures of musculature and adiposity (all P’s ≄ 0.10). CONCLUSIONS: Factors related to sex influence fetal development of the axial skeleton. The smaller vertebral CSA in females is associated with greater flexibility of the spine that could represent the human adaptation to fetal load. Unfortunately, it also imparts a mechanical disadvantage that increases stress within the vertebrae for all physical activities and the susceptibility for fragility fractures later in life

    First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

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    International audienceSpinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

    Search for intermediate mass black hole binaries in the first observing run of Advanced LIGO

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    International audienceDuring their first observational run, the two Advanced LIGO detectors attained an unprecedented sensitivity, resulting in the first direct detections of gravitational-wave signals produced by stellar-mass binary black hole systems. This paper reports on an all-sky search for gravitational waves (GWs) from merging intermediate mass black hole binaries (IMBHBs). The combined results from two independent search techniques were used in this study: the first employs a matched-filter algorithm that uses a bank of filters covering the GW signal parameter space, while the second is a generic search for GW transients (bursts). No GWs from IMBHBs were detected; therefore, we constrain the rate of several classes of IMBHB mergers. The most stringent limit is obtained for black holes of individual mass 100  M⊙, with spins aligned with the binary orbital angular momentum. For such systems, the merger rate is constrained to be less than 0.93  Gpc−3 yr−1 in comoving units at the 90% confidence level, an improvement of nearly 2 orders of magnitude over previous upper limits

    First low-frequency Einstein@Home all-sky search for continuous gravitational waves in Advanced LIGO data

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    International audienceWe report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7  [1/Hz]. At the frequency of best strain sensitivity, near 100 Hz, we set 90% confidence upper limits of 1.8×10-25. At the low end of our frequency range, 20 Hz, we achieve upper limits of 3.9×10-24. At 55 Hz we can exclude sources with ellipticities greater than 10-5 within 100 pc of Earth with fiducial value of the principal moment of inertia of 1038  kg m2
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