317 research outputs found

    Isoprene and monoterpene emissions from alder, aspen and spruce short rotation forest plantations in the UK

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    An expansion of bioenergy has been proposed to help reduce fossil-fuel greenhouse gas emissions, and short-rotation forestry (SRF) can contribute to this expansion. However, SRF plantations could also be sources of biogenic volatile organic compound (BVOC) emissions, which can impact atmospheric air quality. In this study, emissions of isoprene and 11 monoterpenes from the branches and forest floor of hybrid aspen, Italian alder and Sitka spruce stands in an SRF field trial in central Scotland were measured during two years (2018–2019) and used to derive emission potentials for different seasons. Sitka spruce was included as a comparison as it is the most extensive plantation species in the UK. Winter and spring emissions of isoprene and monoterpenes were small compared to those in summer. Sitka spruce had a standardised mean emission rate of 15 ”gCg−1h−1 for isoprene in the dry and warm summer of 2018 – more than double the emissions in 2019. However, standardised mean isoprene emissions from hybrid aspen were similar across both years, approximately 23 ”gCg−1h−1, and standardised mean isoprene emissions from Italian alder were very low. Mean standardised total monoterpene emissions for these species followed a similar pattern of higher standardised emissions in the warmer year: Sitka spruce emitting 4.5 and 2.3 ”gCg−1h−1 for 2018 and 2019, aspen emitting 0.3 and 0.09 ”gCg−1h−1, and Italian alder emitting 1.5 and 0.2 ”gCg−1h−1, respectively. In contrast to these foliage emissions, the forest floor was only a small source of monoterpenes, typically 1 or 2 orders of magnitude lower than foliage emissions on a unit of ground area basis. Estimates of total annual emissions from each plantation type per hectare were derived using the MEGAN 2.1 model. The modelled total BVOC (isoprene and monoterpenes) emissions of SRF hybrid aspen plantations were approximately half those of Sitka spruce for plantations of the same age. Italian alder SRF emissions were 20 times smaller than from Sitka spruce. The expansion of bioenergy plantations to 0.7 Mha has been suggested for the UK to help achieve net-zero greenhouse gas emissions by 2050. The model estimates show that, with such an expansion, total UK BVOC emissions would increase between <1 % and 35 %, depending on the tree species planted. Whereas increases might be small on a national scale, regional increases might have a larger impact on local air quality

    Basic principles of stable isotope analysis in humanitarian forensic science.

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    While the identity of a victim of a localized disaster – such as a train or bus crash – may be established quickly through personal effects, fingerprints, dental records, and a comparison of decedent DNA to family reference specimen DNA, a different scenario presents itself in mass disasters, such as the Asian Tsunami of 2004. In the aftermath of the tsunami, visual appearance was initially used to assign “foreign” or “indigenous” classifications to the remains of thousands of victims. However, this visual identification approach was undermined by the speed with which bodies deteriorated under the hot and humid conditions. Time was spent populating ante-mortem DNA databases for different nationalities, which led to problems when creating a post-mortem DNA database because recovery of viable DNA was compromised due to rapid decomposition. As a consequence, only 1.3% of victims were identified by DNA; in contrast, 61% were identified based on dental examination, although this process took several months and a significant number of deceased from the 2004 Asian Tsunami still remain to be identified

    Improved SOT (Hinode mission) high resolution solar imaging observations

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    We consider the best today available observations of the Sun free of turbulent Earth atmospheric effects, taken with the Solar Optical Telescope (SOT) onboard the Hinode spacecraft. Both the instrumental smearing and the observed stray light are analyzed in order to improve the resolution. The Point Spread Function (PSF) corresponding to the blue continuum Broadband Filter Imager (BFI) near 450 nm is deduced by analyzing i/ the limb of the Sun and ii/ images taken during the transit of the planet Venus in 2012. A combination of Gaussian and Lorentzian functions is selected to construct a PSF in order to remove both smearing due to the instrumental diffraction effects (PSF core) and the large-angle stray light due to the spiders and central obscuration (wings of the PSF) that are responsible for the parasitic stray light. A Max-likelihood deconvolution procedure based on an optimum number of iterations is discussed. It is applied to several solar field images, including the granulation near the limb. The normal non-magnetic granulation is compared to the abnormal granulation which we call magnetic. A new feature appearing for the first time at the extreme- limb of the disk (the last 100 km) is discussed in the context of the definition of the solar edge and of the solar diameter. A single sunspot is considered in order to illustrate how effectively the restoration works on the sunspot core. A set of 125 consecutive deconvolved images is assembled in a 45 min long movie illustrating the complexity of the dynamical behavior inside and around the sunspot.Comment: 15 pages, 22 figures, 1 movi

    Low Complexity Regularization of Linear Inverse Problems

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    Inverse problems and regularization theory is a central theme in contemporary signal processing, where the goal is to reconstruct an unknown signal from partial indirect, and possibly noisy, measurements of it. A now standard method for recovering the unknown signal is to solve a convex optimization problem that enforces some prior knowledge about its structure. This has proved efficient in many problems routinely encountered in imaging sciences, statistics and machine learning. This chapter delivers a review of recent advances in the field where the regularization prior promotes solutions conforming to some notion of simplicity/low-complexity. These priors encompass as popular examples sparsity and group sparsity (to capture the compressibility of natural signals and images), total variation and analysis sparsity (to promote piecewise regularity), and low-rank (as natural extension of sparsity to matrix-valued data). Our aim is to provide a unified treatment of all these regularizations under a single umbrella, namely the theory of partial smoothness. This framework is very general and accommodates all low-complexity regularizers just mentioned, as well as many others. Partial smoothness turns out to be the canonical way to encode low-dimensional models that can be linear spaces or more general smooth manifolds. This review is intended to serve as a one stop shop toward the understanding of the theoretical properties of the so-regularized solutions. It covers a large spectrum including: (i) recovery guarantees and stability to noise, both in terms of ℓ2\ell^2-stability and model (manifold) identification; (ii) sensitivity analysis to perturbations of the parameters involved (in particular the observations), with applications to unbiased risk estimation ; (iii) convergence properties of the forward-backward proximal splitting scheme, that is particularly well suited to solve the corresponding large-scale regularized optimization problem

    Phase II trial of palbociclib in patients with metastatic urothelial cancer after failure of first-line chemotherapy

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    Background: The majority of urothelial cancers (UC) harbor alterations in retinoblastoma (Rb) pathway genes that can lead to loss of Rb tumour suppressor function. Palbociclib is an oral, selective inhibitor of CDK 4/6 that restores Rb function and promotes cell cycle arrest. Methods: In this phase II trial, patients with metastatic platinum-refractory UC molecularly selected for p16 loss and intact Rb by tumour immunohistochemistry received palbociclib 125 mg p.o. daily for 21 days of a 28-day cycle. Primary endpoint was progression-free survival at 4 months (PFS4) using a Simon’s two-stage design. Next-generation sequencing including Rb pathway alterations was conducted. Results: Twelve patients were enrolled and two patients (17%) achieved PFS4 with insufficient activity to advance to stage 2. No responses were seen. Median PFS was 1.9 months (95% CI 1.8–3.7 months) and median overall survival was 6.3 months (95% CI 2.2–12.6 months). Fifty-eight percent of patients had grade ≄3 hematologic toxicity. There were no CDKN2A alterations found and no correlation of Rb pathway alterations with clinical outcome. Conclusions: Palbociclib did not demonstrate meaningful activity in selected patients with platinum-refractory metastatic UC. Further development of palbociclib should only be considered with improved integral biomarker selection or in rational combination with other therapies

    Effect of calcineurin inhibitors on myotoxic activity of crotoxin and Bothrops asper phospholipase A2 myotoxins in vivo and in vitro

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    Previous studies have shown that calcineurin activity plays a critical role in the myotoxic activity induced by crotoxin (CTX), a group II phospholipase A2 (PLA2) with neurotoxic and myotoxic actions. In order to address whether calcineurin is also important for the activity of non-neurotoxic group II PLA2 myotoxins we have compared the effects of calcineurin inhibition on the myotoxic capacity of CTX and the non-neurotoxic PLA2s, myotoxin II (Mt II) and myotoxin III (Mt III) from Bothrops asper venom. Rats were treated with cyclosporin A (CsA) or FK506, calcineurin inhibitors, and received an intramuscular injection of either CTX, Mt II or Mt III into the tibialis anterior. Animals were killed 24 h after injection of toxins. Tibialis anterior was removed and stored in liquid nitrogen. Myofibers in culture were also treated with CsA or FK506 and exposed to CTX, Mt II and Mt III. It was observed that, in contrast to CTX, CsA and FK506 do not attenuate myotoxic effects induced by both Mt II and Mt III in vivo and in vitro. The results of the present study suggest that calcineurin is not essential for the myotoxic activity of Mt II and Mt III, indicating that distinct intracellular pathways might be involved in myonecrosis induced by neurotoxic CTX and non-neurotoxic Bothrops sp. PLA2 myotoxins. Alternatively, calcineurin dependent fast fiber type shift might render the muscle resistant to the action of CTX, without affecting its susceptibility to Bothrops sp. myotoxins.Fundação de Amparo à Pesquisa do Estado de São Paulo/[03/04900-4]/FAPESP/BrasilUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

    'Disc-jet' coupling in black hole X-ray binaries and active galactic nuclei

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    In this chapter I will review the status of our phenomenological understanding of the relation between accretion and outflows in accreting black hole systems. This understanding arises primarily from observing the relation between X-ray and longer wavelength (infrared, radio) emission. The view is necessarily a biased one, beginning with observations of X-ray binary systems, and attempting to see if they match with the general observational properties of active galactic nuclei.Comment: 28 pages, 15 figures, To appear in Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009

    Linear Collider Physics Resource Book for Snowmass 2001, 3: Studies of Exotic and Standard Model Physics

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    This Resource Book reviews the physics opportunities of a next-generation e+e- linear collider and discusses options for the experimental program. Part 3 reviews the possible experiments on that can be done at a linear collider on strongly coupled electroweak symmetry breaking, exotic particles, and extra dimensions, and on the top quark, QCD, and two-photon physics. It also discusses the improved precision electroweak measurements that this collider will make available.This Resource Book reviews the physics opportunities of a next-generation e+e- linear collider and discusses options for the experimental program. Part 3 reviews the possible experiments on that can be done at a linear collider on strongly coupled electroweak symmetry breaking, exotic particles, and extra dimensions, and on the top quark, QCD, and two-photon physics. It also discusses the improved precision electroweak measurements that this collider will make available
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