517 research outputs found
Low level of virological failure and drug resistance among patients receiving antiretroviral treatment under programme conditions in Maputo, Mozambique
Mexico AIDS Conference 200
Organisational activity with land managers in relation to biodiversity renewal in four case study areas. A scoping study
This is the final version. Available from the Centre for Rural Policy Research, University of Exeter via the link in this recordIntroduction: This scoping study forms part of a wider examination of land manager engagement with biodiversity
renewal, contributing to the Theme 3 objectives of RENEW. The purpose of this study was to identify
how organisations are currently engaging with land managers in relation to biodiversity renewal
across the four case study areas identified by the wider team, through the identification of existing
(or recent) biodiversity renewal initiatives and biodiversity renewal-related networks of farmers in
those areas. It also aimed to investigate stakeholder perceptions around levels of engagement, and
the potential impacts upon land managers of the agricultural transition, as well as to monitor initial
responses of organisational stakeholders to the ENABLR (Engagement in Nature and Biodiversity Land
Renewal) decision-support tool currently being developed within Theme 3. These findings allow the
research team to âmapâ key areas of activity (and non-activity) in the four case study areas, while at
the same time providing an extensive knowledge base around which to develop future research
methods (such as interviews) and be able to interact with participants from an informed position.
Findings may also assist and influence the development of the decision-support tool.Natural Environment Research Council (NERC
Bio-Inspired Multi-Layer Spiking Neural Network Extracts Discriminative Features from Speech Signals
Spiking neural networks (SNNs) enable power-efficient implementations due to
their sparse, spike-based coding scheme. This paper develops a bio-inspired SNN
that uses unsupervised learning to extract discriminative features from speech
signals, which can subsequently be used in a classifier. The architecture
consists of a spiking convolutional/pooling layer followed by a fully connected
spiking layer for feature discovery. The convolutional layer of leaky,
integrate-and-fire (LIF) neurons represents primary acoustic features. The
fully connected layer is equipped with a probabilistic spike-timing-dependent
plasticity learning rule. This layer represents the discriminative features
through probabilistic, LIF neurons. To assess the discriminative power of the
learned features, they are used in a hidden Markov model (HMM) for spoken digit
recognition. The experimental results show performance above 96% that compares
favorably with popular statistical feature extraction methods. Our results
provide a novel demonstration of unsupervised feature acquisition in an SNN
Mechanochemical synthesis and ion transport properties of Na<sub>3</sub>OX (X = Cl, Br, I and BH<sub>4</sub>) antiperovskite solid electrolytes
The push towards the development of next-generation solid-state batteries has motivated the search for novel solid electrolyte materials. Sodium antiperovskites represent a structural family of ion conductors that has emerged as a result, with expected advantages in terms of composition tuning, electrochemical stability, mechanical softness and high ionic conductivity. Here, we report the mechanochemical synthesis of several materials in this structural family, including novel mixed-halide compositions such as Na3OCl0.5(BH4)0.5, Na3OBr0.5(BH4)0.5 Na3OI0.5(BH4)0.5 and Na3OCl0.33Br0.33(BH4)0.33. We rationalize the effect of halide substitution on the structure and ion transport properties of these materials through diffraction, impedance spectroscopy and molecular dynamics. We conclude with a discussion on Na3OBH4, which has recently been reported to be a fast ion conductor, owing to the rotational disorder of the complex superhalide anion BH4â. We are unable to reproduce the reported high ionic conductivity of Na3OBH4 neither by experiment nor ab initio simulation.</p
The Future Mortality of High Mortality Countries: A Model Incorporating Expert Arguments
This paper examines the future of mortality in the 65 countries still experiencing high mortality in 2010, as defined by a cutoff of 40 deaths before age five per thousand live births. Mortality declines in several countries stagnated or reversed in the last two decades of the twentieth century due mainly to HIV/AIDS. The forces underlying past mortality trends and affecting the future course of mortality are examined by reviewing the existing literature and reporting the results of the global survey and invited meeting, both involving mortality experts. The experts assessed the likelihood and weight of forces hypothesized to influence mortality. A statistical model is combined with these expert assessments to produce a set of mortality assumptions that are incorporated into the projections reported in this paper. This paper also addresses the limited availability of reliable data on age-specific mortality rates
Engaging land managers for nature conservation and renewal: A Practical guide for environmental groups
Also available on Zenodo via the DOI in this recordThe UK is in a climate emergency and ecological
crisis. Key to addressing environmental
problems, such as improving water quality and
renewing biodiversity, involves tackling the
way land is managed. But effective
environmental land management depends on
much more than scientific knowledge. It rests
on an appropriate translation of the science by
environmental groups and its effective
implementation by land managers themselves.
To achieve the latter, land managers must also
be given ample opportunities to communicate
their knowledge and expertise of the land. As
such, it is essential for environmental groups to
understand how best to engage with those key
actors.
The guidance provided in this report aims to
support those groups in their engagement with
land managers in such a way as to empower
them to move towards more sustainable and
regenerative land management practices. It
comprises clear and concise guidance on
effective engagement. This guidance draws
heavily from the wealth of experience of
Cornwall Wildlife Trust staff involved in the
Upstream Thinking catchment management
scheme funded by South West Water. The aim
of this scheme is to improve water quality,
increase biodiversity, and maintain viable farm
businesses. Staff working on this scheme have
developed immensely valuable engagement
skills as part of their work with farmers in
catchment systems over the past ten years.
The document is organized into two sections:
âengagement principlesâ and âengagement
steps.â The former lists some key behavioural
qualities for effective engagement with land
managers. The latter lists the different steps
and actions involved in building an effective
engagement over time. The guidance applies
to all types of environmental management
plans involving a land manager and land
adviser, including but not limited to those
designed as part of existing agri-environment
schemes (AES).Natural Environment Research Council (NERC
Crystal Structures, Local Atomic Environments, and Ion Diffusion Mechanisms of Scandium-Substituted Sodium Superionic Conductor (NASICON) Solid Electrolytes
The importance of exploring new solid electrolytes for all-solid-state batteries has led to significant interest in NASICON-type materials. Here, the Sc3+-substituted NASICON compositions Na3ScxZr2-x(SiO4)2-x(PO4)1+x (termed N3) and Na2ScyZr2-y(SiO4)1-y(PO4)2+y (termed N2) (x, y = 0 â 1) are studied as model Na+-ion conducting electrolytes for solid-state batteries. The influence of Sc3+ substitution on the crystal structures and local atomic environments has been characterized by powder X-ray diffraction (XRD) and neutron powder diffraction (NPD), as well as solid-state 23Na, 31P, and 29Si nuclear magnetic resonance (NMR) spectroscopy. A phase transition between 295 and 473 K from monoclinic C2/c to rhombohedral R c is observed for the N3 compositions, while N2 compositions crystallize in a rhombohedral R c unit cell in this temperature range. Alternating current (AC) impedance spectroscopy, molecular dynamics (MD) and high temperature 23Na NMR are in good agreement, showing that with a higher Sc3+ concentration, the ionic conductivity (about 10-4 S/cm at 473 K) decreases and the activation energy for ion diffusion increases. 23Na NMR experiments indicate that the nature of the Na+-ion motion is two-dimensional on the local atomic scale of NMR though the long-range diffusion pathways are three-dimensional. In addition, a combination of MD, bond valence, maximum entropy/Rietveld and van Hove correlation methods has been used, to reveal that the Na+-ion diffusion in these NASICON materials is three-dimensional and that there is a continuous exchange of sodium between Na(1) and Na(2) sites
FHR4-based immunoconjugates direct complement-dependent cytotoxicity and phagocytosis towards HER2-positive cancer cells
Directing selective complement activation towards tumour cells is an attractive strategy to promote their elimination. In the present work, we have generated heteromultimeric immunoconjugates that selectively activate the complement alternative pathway (AP) on tumour cells. We used the C4b-binding protein C-terminal-alpha-/beta-chain scaffold for multimerisation to generate heteromultimeric immunoconjugates displaying (a) a multivalent-positive regulator of the AP, the human factor H-related protein 4 (FHR4) with; (b) a multivalent targeting function directed against erbB2 (HER2); and (c) a monovalent enhanced GFP tracking function. Two distinct VHH targeting two different epitopes against HER2 and competing either with trastuzumab or with pertuzumab-recognising epitopes [VHH(T) or VHH(P)], respectively, were used as HER2 anchoring moieties. Optimised high-FHR4 valence heteromultimeric immunoconjugates [FHR4/VHH(T) or FHR4/VHH(P)] were selected by sequential cell cloning and a selective multistep His-Trap purification. Optimised FHR4-heteromultimeric immunoconjugates successfully overcame FH-mediated complement inhibition threshold, causing increased C3b deposition on SK-OV-3, BT474 and SK-BR3 tumour cells, and increased formation of lytic membrane attack complex densities and complement-dependent cytotoxicity (CDC). CDC varies according to the pattern expression and densities of membrane-anchored complement regulatory proteins on tumour cell surfaces. In addition, opsonised BT474 tumour cells were efficiently phagocytosed by macrophages through complement-dependent cell-mediated cytotoxicity. We showed that the degree of FHR4-multivalency within the multimeric immunoconjugates was the key element to efficiently compete and deregulate FH and FH-mediated convertase decay locally on tumour cell surface. FHR4 can thus represent a novel therapeutic molecule, when expressed as a multimeric entity and associated with an anchoring system, to locally shift the complement steady-state towards activation on tumour cell surface
Structural and Mechanistic Insights into Fast Lithium-Ion Conduction in Li4SiO4-Li3PO4 Solid Electrolytes.
Solid electrolytes that are chemically stable and have a high ionic conductivity would dramatically enhance the safety and operating lifespan of rechargeable lithium batteries. Here, we apply a multi-technique approach to the Li-ion conducting system (1-z)Li4SiO4-(z)Li3PO4 with the aim of developing a solid electrolyte with enhanced ionic conductivity. Previously unidentified superstructure and immiscibility features in high-purity samples are characterized by X-ray and neutron diffraction across a range of compositions (z = 0.0-1.0). Ionic conductivities from AC impedance measurements and large-scale molecular dynamics (MD) simulations are in good agreement, showing very low values in the parent phases (Li4SiO4 and Li3PO4) but orders of magnitude higher conductivities (10(-3) S/cm at 573 K) in the mixed compositions. The MD simulations reveal new mechanistic insights into the mixed Si/P compositions in which Li-ion conduction occurs through 3D pathways and a cooperative interstitial mechanism; such correlated motion is a key factor in promoting high ionic conductivity. Solid-state (6)Li, (7)Li, and (31)P NMR experiments reveal enhanced local Li-ion dynamics and atomic disorder in the solid solutions, which are correlated to the ionic diffusivity. These unique insights will be valuable in developing strategies to optimize the ionic conductivity in this system and to identify next-generation solid electrolytes.The ALISTORE ERI and CNRS are acknowledged for supporting Y.D. through a joint Ph.D. scholarship between Picardie (France) and Bath (UK). The authors thank D. Sheptyakov (PSI, Switzerland) and M. Bianchini (ILL-Grenoble, France) for assistance with neutron diffraction experiments, and M. T. Dunstan (Cambridge, UK) for assistance with NMR experiments. Financial support from the EPSRC Energy Materials Programme (Grant EP/K016288) is gratefully acknowledged. The HPC Materials Chemistry Consortium (EP/L000202) allowed use of the ARCHER facilities. O.P. and S.E. acknowledge support from a Marie SkĆodowska-Curie Fellowship (H2020-MSCA-IF-2014-EF, no. 655444) and an ERASMUS+ scholarship, respectively.This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/jacs.5b0444
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