414 research outputs found

    Mainstreaming ecosystem science in spatial planning practice : exploiting a hybrid opportunity space

    Get PDF
    This paper develops a framework for improved mainstreaming of ecosystem science in policy and decision-making within a spatial planning context. Ecosystem science is advanced as a collective umbrella to capture a body of work and approaches rooted in social-ecological systems thinking, spawning a distinctive ecosystem terminology: ecosystem approach, ecosystem services, ecosystem services framework and natural capital. The interface between spatial planning and ecosystem science is explored as a theoretical opportunity space to improve mainstreaming processes adapting Rogers’ (2003) diffusion model. We introduce the twin concepts of hooks (linking ecosystem science to a key policy or legislative term, duty or priority that relate to a particular user group) and ‘bridges’ (linking ecosystem science to a term, concept or policy priority that is used and readily understood across multiple groups and publics) as translational mechanisms in transdisciplinary mainstreaming settings. We argue that ecosystem science can be embedded into the existing work priorities and vocabularies of spatial planning practice using these hooks and bridges. The resultant framework for mainstreaming is then tested, drawing on research funded as part of the UK National Ecosystem Assessment Follow-On programme (2012-2014), within 4 case studies; each reflecting different capacities, capabilities, opportunities and barriers. The results reveal the importance of leadership, political buy in, willingness to experiment outside established comfort zones and social learning as core drivers supporting mainstreaming processes. Whilst there are still significant challenges in mainstreaming in spatial planning settings, the identification and use of hooks and bridges collectively, enables traction to be gained for further advances; moving beyond the status quo to generate additionality and potential behaviour change within different modes of mainstreaming practice. This pragmatic approach has global application to help improve the way nature is respected and taken account of in planning systems nationally and globally

    Confirmation Sampling for Exact Nearest Neighbor Search

    Get PDF
    Locality-sensitive hashing (LSH), introduced by Indyk and Motwani in STOC ’98, has been an extremely influential framework for nearest neighbor search in high-dimensional data sets. While theoretical work has focused on the approximate nearest neighbor problem, in practice LSH data structures with suitably chosen parameters are used to solve the exact nearest neighbor problem (with some error probability). Sublinear query time is often possible in practice even for exact nearest neighbor search, intuitively because the nearest neighbor tends to be significantly closer than other data points. However, theory offers little advice on how to choose LSH parameters outside of pre-specified worst-case settings. We introduce the technique of confirmation sampling for solving the exact nearest neighbor problem using LSH. First, we give a general reduction that transforms a sequence of data structures that each find the nearest neighbor with a small, unknown probability, into a data structure that returns the nearest neighbor with probability 1−δ , using as few queries as possible. Second, we present a new query algorithm for the LSH Forest data structure with L trees that is able to return the exact nearest neighbor of a query point within the same time bound as an LSH Forest of Ω(L) trees with internal parameters specifically tuned to the query and data

    Tilt order parameters, polarity and inversion phenomena in smectic liquid crystals

    Full text link
    The order parameters for the phenomenological description of the smectic-{\it A} to smectic-{\it C} phase transition are formulated on the basis of molecular symmetry and structure. It is shown that, unless the long molecular axis is an axis of two-fold or higher rotational symmetry, the ordering of the molecules in the smectic-{\it C} phase gives rise to more than one tilt order parameter and to one or more polar order parameters. The latter describe the indigenous polarity of the smectic-{\it C} phase, which is not related to molecular chirality but underlies the appearance of spontaneous polarisation in chiral smectics. A phenomenological theory of the phase transition is formulated by means of a Landau expansion in two tilt order parameters (primary and secondary) and an indigenous polarity order parameter. The coupling among these order parameters determines the possibility of sign inversions in the temperature dependence of the spontaneous polarisation and of the helical pitch observed experimentally for some chiral smectic-{\it C∗C^{\ast}} materials. The molecular interpretation of the inversion phenomena is examined in the light of the new formulation.Comment: 12 pages, 5 figures, RevTe

    Microstructural analysis of TRISO particles using multi-scale X-ray computed tomography

    Get PDF
    TRISO particles, a composite nuclear fuel built up by ceramic and graphitic layers, have outstanding high temperature resistance. TRISO fuel is the key technology for High Temperature Reactors (HTRs) and the Generation IV Very High Temperature Reactor (VHTR) variant. TRISO offers unparalleled containment of fission products and is extremely robust during accident conditions. An understanding of the thermal performance and mechanical properties of TRISO fuel requires a detailed knowledge of pore sizes, their distribution and interconnectivity. Here 50 nm, nano-, and 1 μm resolution, micro-computed tomography (CT), have been used to quantify non-destructively porosity of a surrogate TRISO particle at the 0.3–10 μm and 3–100 μm scales respectively. This indicates that pore distributions can reliably be measured down to a size approximately 3 times the pixel size which is consistent with the segmentation process. Direct comparison with Scanning Electron Microscopy (SEM) sections indicates that destructive sectioning can introduce significant levels of coarse damage, especially in the pyrolytic carbon layers. Further comparative work is required to identify means of minimizing such damage for SEM studies. Finally since it is non-destructive, multi-scale time-lapse X-ray CT opens the possibility of intermittently tracking the degradation of TRISO structure under thermal cycles or radiation conditions in order to validate models of degradation such as kernel movement. X-ray CT in-situ experimentation of TRISO particles under load and temperature could also be used to understand the internal changes that occur in the particles under accident conditions.Scanning and analysis was performed at the Henry Moseley X-ray Imaging Facility which has been funded through support from EPSRC under Grants EP/F007906, EP/F028431 and EP/I02249X. Imaging on the UltraXRM-L200 system was carried out at Zeiss Xradia Inc., Pleasanton, CA, USA

    Dispositional optimism as a correlate of decision-making styles in adolescence

    Get PDF
    Despite the numerous psychological areas in which optimism has been studied, including career planning, only a small amount of research has been done to investigate the relationship between optimism and decision-making styles. Consequently, we have investigated the role of dispositional optimism as a correlate of different decision-making styles, in particular, positive for effective styles and negative for ineffective ones (doubtfulness, procrastination, and delegation). Data were gathered through questionnaires administered to 803 Italian adolescents in their last 2 years of high schools with different fields of study, each at the beginning stages of planning for their professional future. A paper questionnaire was completed containing measures of dispositional optimism and career-related decision styles, during a vocational guidance intervention conducted at school. Data were analyzed using stepwise multiple regression. Results supported the proposed model by showing optimism to be a strong correlate of decision-making styles, thereby offering important intervention guidelines aimed at modifying unrealistically negative expectations regarding their future and helping students learn adaptive decision-making skills

    Importance of heterogeneity in Porhyromonas gingivalis lipopolysaccharide lipid A in tissue specific inflammatory signaling

    Get PDF
    Lipopolysaccharide (LPS) of Porphyromonas gingivalis exists in at least two known forms, O-LPS and A-LPS. A-LPS shows heterogeneity in which two isoforms designated LPS1435/1449 and LPS1690 appear responsible for tissue specific immune signalingpathways activation and increased virulence. The modification of lipid A to tetra-acylated1435/1449 and/or penta-acylated1690 fatty acids indicates poor growth conditions and bioavailability of hemin. Hemin protects P. gingivalis from serum resistance and the lipid A serves as a site for its binding. The LPS1435/1449 and LPS1690 isoforms can produce opposite effects on the human Toll-like receptors (TLR) TLR 2 and TLR 4 activation. This enabless P. gingivalis to select the conditions for its entry, survival and that of its co-habiting species in the host, orchestrating its virulence to control innate immune pathway activation and biofilm dysbiosis. Thismini review describes a number of effects that LPS1435/1449 and LPS1690 can exert on the host tissues such as deregulation of the innate immune system, subversion of host cell autophagy, regulation of outer membrane vesicle production and adverse effects on pregnancy outcome. The ability to change its LPS1435/1449 and/or LPS1690 composition may enables P. gingivalis to paralyze local pro-inflammatory cytokine production, thereby gaining access to its primary location in periodontal tissue

    Possible Associations of NTRK2 Polymorphisms with Antidepressant Treatment Outcome: Findings from an Extended Tag SNP Approach

    Get PDF
    Background: Data from clinical studies and results from animal models suggest an involvement of the neurotrophin system in the pathology of depression and antidepressant treatment response. Genetic variations within the genes coding for the brain-derived neurotrophic factor (BDNF) and its key receptor Trkb (NTRK2) may therefore influence the response to antidepressant treatment. Methods: We performed a single and multi-marker association study with antidepressant treatment outcome in 398 depressed Caucasian inpatients participating in the Munich Antidepressant Response Signature (MARS) project. Two Caucasian replication samples (N = 249 and N = 247) were investigated, resulting in a total number of 894 patients. 18 tagging SNPs in the BDNF gene region and 64 tagging SNPs in the NTRK2 gene region were genotyped in the discovery sample; 16 nominally associated SNPs were tested in two replication samples. Results: In the discovery analysis, 7 BDNF SNPs and 9 NTRK2 SNPs were nominally associated with treatment response. Three NTRK2 SNPs (rs10868223, rs1659412 and rs11140778) also showed associations in at least one replication sample and in the combined sample with the same direction of effects (PcorrP_{corr} = .018, PcorrP_{corr} = .015 and PcorrP_{corr} = .004, respectively). We observed an across-gene BDNF-NTRK2 SNP interaction for rs4923468 and rs1387926. No robust interaction of associated SNPs was found in an analysis of BDNF serum protein levels as a predictor for treatment outcome in a subset of 93 patients. Conclusions/Limitations: Although not all associations in the discovery analysis could be unambiguously replicated, the findings of the present study identified single nucleotide variations in the BDNF and NTRK2 genes that might be involved in antidepressant treatment outcome and that have not been previously reported in this context. These new variants need further validation in future association studies

    Spike-Timing-Based Computation in Sound Localization

    Get PDF
    Spike timing is precise in the auditory system and it has been argued that it conveys information about auditory stimuli, in particular about the location of a sound source. However, beyond simple time differences, the way in which neurons might extract this information is unclear and the potential computational advantages are unknown. The computational difficulty of this task for an animal is to locate the source of an unexpected sound from two monaural signals that are highly dependent on the unknown source signal. In neuron models consisting of spectro-temporal filtering and spiking nonlinearity, we found that the binaural structure induced by spatialized sounds is mapped to synchrony patterns that depend on source location rather than on source signal. Location-specific synchrony patterns would then result in the activation of location-specific assemblies of postsynaptic neurons. We designed a spiking neuron model which exploited this principle to locate a variety of sound sources in a virtual acoustic environment using measured human head-related transfer functions. The model was able to accurately estimate the location of previously unknown sounds in both azimuth and elevation (including front/back discrimination) in a known acoustic environment. We found that multiple representations of different acoustic environments could coexist as sets of overlapping neural assemblies which could be associated with spatial locations by Hebbian learning. The model demonstrates the computational relevance of relative spike timing to extract spatial information about sources independently of the source signal
    • …
    corecore