1,226 research outputs found

    Targeting conservation actions at species threat response thresholds

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    To improve the status of the world’s biodiversity by 2030, conservation actions must not only seek to halt or slow biodiversity loss, they must increase species’ populations. A better mechanistic understanding of biodiversity loss and of species’ sensitivities to certain intensities of threats is needed to target conservation actions effectively. Moving beyond ordinal space-for-time substitution analyses, towards monitoring concurrent changes in threats and species’ populations over time will help achieve this. We propose a framework to quantify species’ response thresholds along gradients of threat intensity, using a combination of threat-sensitive taxa, biogeographic regions, and biomes. This framework will allow efficient targeting of conservation actions, of relevance to global policy-making

    A comparison of magnetic resonance, X-ray and positron emission particle tracking measurements of a single jet of gas entering a bed of particles

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    Measurements of the lengths of a single jet of gas entering a packed bed were made using magnetic resonance imaging (MRI), positron emission particle tracking (PEPT) and X-ray radiography and the results compared. The experiments were performed using a Perspex bed (50 mm i.d.) of poppy seeds: air at 298 K was admitted to the base of the bed through a single, central orifice, 2 mm in diameter. Poppy seeds (Geldart Group B, measured minimum fluidisation velocity with air at 298 K and 1 atm of 0.13 m/s and particle density ~1060 kg/m3) were used because of their high content of oil, which contains mobile protons and hence is suitable for MRI examination. The lengths of jet measured using the three techniques were in agreement between 50 m/s < Uo < 100 m/s, where Uo is the superficial velocity through the orifice. Below Uo = 50 m/s, X-ray measurements of jet lengths were shorter than those measured using MRI. This was attributed to the minimum diameter of void, found to be 5 mm, detectable in a 50 mm bed using ultra-fast X-ray measurements. PEPT is most commonly used to calculate particle velocities, whilst jet lengths are usually calculated from determinations of voidage. However, the particle locations determined in this work by PEPT were used to calculate a fractional occupancy count, from which a jet length could be inferred.RCUK, OtherThis is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.ces.2014.09.02

    Poly(amino acid)-polyester graft copolymer nanoparticles for the acid-mediated release of doxorubicin

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    Biodegradable polymers have emerged as highly effective drug delivery vehicles. We combine N-carboxyanhydride and O-carboxyanhydride ring opening polymerisations to synthesise a poly(amino acid)-polyester graft copolymer capable of encapsulating, and subsequently releasing doxorubicin via acid-mediated hydrolysis. Consequently, the nanoparticles detailed are extremely promising vehicles for the controlled delivery of chemotherapeutic agents

    Spectral reflectance properties of iridescent pierid butterfly wings

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    The wings of most pierid butterflies exhibit a main, pigmentary colouration: white, yellow or orange. The males of many species have in restricted areas of the wing upper sides a distinct structural colouration, which is created by stacks of lamellae in the ridges of the wing scales, resulting in iridescence. The amplitude of the reflectance is proportional to the number of lamellae in the ridge stacks. The angle-dependent peak wavelength of the observed iridescence is in agreement with classical multilayer theory. The iridescence is virtually always in the ultraviolet wavelength range, but some species have a blue-peaking iridescence. The spectral properties of the pigmentary and structural colourations are presumably tuned to the spectral sensitivities of the butterflies’ photoreceptors

    Accreting Black Holes

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    This chapter provides a general overview of the theory and observations of black holes in the Universe and on their interpretation. We briefly review the black hole classes, accretion disk models, spectral state classification, the AGN classification, and the leading techniques for measuring black hole spins. We also introduce quasi-periodic oscillations, the shadow of black holes, and the observations and the theoretical models of jets.Comment: 41 pages, 18 figures. To appear in "Tutorial Guide to X-ray and Gamma-ray Astronomy: Data Reduction and Analysis" (Ed. C. Bambi, Springer Singapore, 2020). v3: fixed some typos and updated some parts. arXiv admin note: substantial text overlap with arXiv:1711.1025

    Towards a sustainable, participatory and inclusive wild meat sector

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    The meat of wild species, referred to in this report as 'wild meat', is an essential source of protein and a generator of income for millions of forest-living communities in tropical and subtropical regions. However, unsustainable harvest rates currently endanger the integrity of ecosystems and threaten the livelihoods of many vulnerable households. This report, produced in response to a call from the Secretariat of the Convention on Biological Diversity (CBD), is a technical tool to help users guide actions towards a more sustainable wild meat sector. Here, we present an extensive compilation of the current knowledge on wild meat use, drivers and impacts, and provide recommendations on how to improve wild meat governance and management. In all tropical and subtropical regions, greater wildlife offtakes are being enabled by advances in hunting technologies, as well as the increased penetration of new lands by infrastructure, logging, mining and agriculture. Consumers in fast-growing urban centers largely drive demand for wild meat, where it is eaten as a luxury item rather than as a food staple. This greater pressure from large towns and cities has had significant impacts on wildlife populations and ecosystem integrity. In turn, this jeopardizes the financial 'safety nets' and food security of remote rural and indigenous communities, for whom wild meat can account for much of their dietary protein, as well as an important source of other nutrients. Key to the success of sustainable management is ensuring that wild meat use is considered a cross-sectoral issue; firmly incorporated in national resource and land-use planning. The success of management strategies will depend on an enabling environment at the national level. In many countries a key first step will be the revision of national hunting laws and land tenure governance systems in consultation with multiple stakeholders. Research efforts must focus on producing science-based evidence that governments, communities, NGOs and industries can use to improve management policies and practices. The creation of a sustainable wild meat sector requires interconnected interventions along the entire value chain - focused on local hunting communities, urban consumers and wider society. Well-designed, participatory approaches can enable sustainable management of wild meat supply for local communities, but only if this is strongly complemented by approaches that aim to reduce urban demand

    Seeking legitimacy through CSR: Institutional Pressures and Corporate Responses of Multinationals in Sri Lanka

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    Arguably, the corporate social responsibility (CSR) practices of multinational enterprises (MNEs) are influenced by a wide range of both internal and external factors. Perhaps most critical among the exogenous forces operating on MNEs are those exerted by state and other key institutional actors in host countries. Crucially, academic research conducted to date offers little data about how MNEs use their CSR activities to strategically manage their relationship with those actors in order to gain legitimisation advantages in host countries. This paper addresses that gap by exploring interactions between external institutional pressures and firm-level CSR activities, which take the form of community initiatives, to examine how MNEs develop their legitimacy-seeking policies and practices. In focusing on a developing country, Sri Lanka, this paper provides valuable insights into how MNEs instrumentally utilise community initiatives in a country where relationship-building with governmental and other powerful non-governmental actors can be vitally important for the long-term viability of the business. Drawing on neo-institutional theory and CSR literature, this paper examines and contributes to the embryonic but emerging debate about the instrumental and political implications of CSR. The evidence presented and discussed here reveals the extent to which, and the reasons why, MNEs engage in complex legitimacy-seeking relationships with Sri Lankan institutions

    Autism as a disorder of neural information processing: directions for research and targets for therapy

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    The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself
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