7,487 research outputs found

    Edge Extraction Based on Aperture Synthesis in Optical Scanning Holography

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    Poster Session (DW2A): no. DW2A.6We present an edge extraction method based on aperture synthesis with different pupils in optical scanning holography. By utilizing two sub-holograms covering different spatial frequency ranges of the object, sharp edges can be extracted successfully. © 2015 OSApostprin

    Convergence of finite volume scheme for degenerate parabolic problem with zero flux boundary condition

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    This note is devoted to the study of the finite volume methods used in the discretization of degenerate parabolic-hyperbolic equation with zero-flux boundary condition. The notion of an entropy-process solution, successfully used for the Dirichlet problem, is insufficient to obtain a uniqueness and convergence result because of a lack of regularity of solutions on the boundary. We infer the uniqueness of an entropy-process solution using the tool of the nonlinear semigroup theory by passing to the new abstract notion of integral-process solution. Then, we prove that numerical solution converges to the unique entropy solution as the mesh size tends to 0

    Evaluation of cross-beam vector Doppler ultrasound systems for accurate 3-D velocity measurements

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    Vector Doppler ultrasound (VDUS) systems offer the potential for improved accuracy in mapping of complex flow parameters, such as recirculation, turbulence, and shear stress which are probable risk factors leading to vascular disease and stroke. Cross-beam VDUS systems were evaluated for velocity accuracy to optimize the number of receivers for the inter-beam angle, wall filter, system orientation, and complexity of flow seen in a stenosed carotid artery. Preliminary results for velocity estimation show promise for validation of numerical results. © 2012 IEEE.published_or_final_versio

    A novel intelligent system for securing cash levels using Markov random fields

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    Financial support from the Spanish Ministry of Universities "Disruptive group decision making systems in fuzzy context: Applications in smart energy and people analytics" (PID2019-103880RB-I00), and Junta de Andalucia (SEJ340) is gratefully acknowledged.The maintenance of cash levels under certain security thresholds is key for the health of the banking sector. In this paper, the monitoring process of branch network cash levels is performed using a single intelligent system which should provide an alert when there are cash shortages at any point of the network. Such an integral solution would provide a unified insight that guarantees that branches with similar cash features are secured as a whole. That is to say, a triggered alarm at a specific branch would indicate that attention must also be paid to similar (in-cash-feature) branches. The system also incorporates a (complementary) specific treatment for individual branches. The Early Warning System for securing cash levels presented in this paper (cash level EWS) is deliberately free of local demographic specifications, thereby overcoming the current lack of worldwide definitions for local demographics. This aspect would be particularly valuable for banking institutions with branch networks all over the world. A further benefit is the cost reductions that are a result of replacing several approaches with a single global one. Instead of local demographic parameters, a solid theoretical model based on Markov random fields (MRFs) has been developed. The use of MRFs means a reduction in the amount of information required. This would mean a higher processing speed as well as a significant reduction in the amount of storage capacity required. To the best of the author's knowledge, this is the first time that MRFs have been applied to cash monitoring.Spanish Ministry of Universities PID2019-103880RB-I00Junta de Andalucia SEJ34

    Evaluating the ecological and social targeting of a compensation scheme in Bangladesh.

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    Conservation payments are increasingly advocated as a way to meet both social and ecological objectives, particularly in developing countries, but these payments often fail to reach the 'right' individuals. The Government of Bangladesh runs a food compensation scheme that aims to contribute to hilsa (Tenualosa ilisha) conservation by improving the socioeconomic situation of households affected by hilsa sanctuary fishing bans. Analysing data from a household survey of compensation recipients and non-recipients, we identify the current correlates of compensation distribution and explore perceptions of fairness in this distribution. We find that distribution is largely spatial rather than based on the household characteristics that are supposed to determine eligibility for compensation, indicating political influence in the distribution process. We also find the compensation scheme is widely perceived to be unfair, which could be undermining its potential to compensate vulnerable fishers while improving compliance with fishing bans. The spatial distribution of compensation would shift substantially under alternative targeting scenarios that are likely to improve the cost-effectiveness of the scheme, such as targeting those who are most dependent on fishing for their livelihood. This study highlights a challenge for conservation payment schemes that aim to achieve the dual objectives of poverty reduction and ecological sustainability, particularly large-scale public schemes, and suggests that more effective targeting and transparency about the basis of payment distribution are prerequisites for schemes to be both cost-effective and socially acceptable

    Radial Growth of Qilian Juniper on the Northeast Tibetan Plateau and Potential Climate Associations

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    There is controversy regarding the limiting climatic factor for tree radial growth at the alpine treeline on the northeastern Tibetan Plateau. In this study, we collected 594 increment cores from 331 trees, grouped within four altitude belts spanning the range 3550 to 4020 m.a.s.l. on a single hillside. We have developed four equivalent ring-width chronologies and shown that there are no significant differences in their growth-climate responses during 1956 to 2011 or in their longer-term growth patterns during the period AD 1110–2011. The main climate influence on radial growth is shown to be precipitation variability. Missing ring analysis shows that tree radial growth at the uppermost treeline location is more sensitive to climate variation than that at other elevations, and poor tree radial growth is particularly linked to the occurrence of serious drought events. Hence water limitation, rather than temperature stress, plays the pivotal role in controlling the radial growth of Sabina przewalskii Kom. at the treeline in this region. This finding contradicts any generalisation that tree-ring chronologies from high-elevation treeline environments are mostly indicators of temperature changes

    Division of Giardia isolates from humans into two genetically distinct assemblages by electrophoretic analysis of enzyme encoded at 27 loci in comparison with Giardia muris

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    Giardia that infect humans are known to be heterogeneous but they are assigned currently to a single species, Giardia intestinalis (syn. G. lamblia). The genetic differences that exist within G. intestinalis have not yet been assessed quantitatively and neither have they been compared in magnitude with those that exist between G. intestinalis and species that are morphologically similar (G. duodenalis) or morphologically distinct (e.g. G. muris). In this study, 60 Australian isolates of G. intestinalis were analysed electrophoretically at 27 enzyme loci and compared with G. muris and a feline isolate of G. duodenalis. Isolates of G. intestinalis were distinct genetically from both G. muris (approximately 80% fixed allelic differences) and the feline G. duodenalis isolate (approximately 75% fixed allelic differences). The G. intestinalis isolates were extremely heterogeneous but they fell into 2 major genetic assemblages, separated by fixed allelic differences at approximately 60% of loci examined. The magnitude of the genetic differences between the G. intestinalis assemblages approached the level that distinguished the G. duodenalis isolate from the morphologically distinct G. muris. This raises important questions about the evolutionary relationships of the assemblages with Homo sapiens, the possibility of ancient or contemporary transmission from animal hosts to humans and the biogeographical origins of the two clusters.G. Mayrhofer, R. H. Andrews, P. L. Ey and N. B. Chilto

    Retrospective unbiased plasma lipidomic of progressive multiple sclerosis patients-identifies lipids discriminating those with faster clinical deterioration.

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    The disease course of patients with a confirmed diagnosis of primary progressive multiple sclerosis (PPMS) is uncertain. In an attempt to identify potential signaling pathways involved in the evolution of the disease, we conducted an exploratory unbiased lipidomic analysis of plasma from non‑diseased controls (n = 8) and patients with primary progressive MS (PPMS, n = 19) and either a rapid (PPMS‑P, n = 9) or slow (PPMS‑NP, n = 10) disease course based on worsening disability and/or MRI‑visible appearance of new T2 lesions over a one‑year‑assessment. Partial least squares‑discriminant analysis of the MS/MSALL lipidomic dataset, identified lipids driving the clustering of the groups. Among these lipids, sphingomyelin‑d18:1/14:0 and mono‑hexosylceramide‑d18:1/20:0 were differentially abundant in the plasma of ppMS patients compared to controls and their levels correlated with MRI signs of disease progression. Lyso‑phosphatidic acid‑18:2 (LPA‑18:2) was the only lipid with significantly lower abundance in PPMS patients with a rapidly deteriorating disease course, and its levels inversely correlated with the severity of the neurological deficit. Decreased levels of LPA‑18:2 were detected in patients with more rapid disease progression, regardless of therapy and these findings were validated in an independent cohort of secondary progressive (SPMS) patients, but not in a third cohorts of relapsing–remitting (RRMS) patients. Collectively, our analysis suggests that sphingomyelin‑d18:1/14:0, mono‑hexosylceramide‑d18:1/20:0, and LPA‑18:2 may represent important targets for future studies aimed at understanding disease progression in MS

    Effect of polar amino acid incorporation on Fmoc-diphenylalanine-based tetrapeptides.

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    Peptide hydrogels show great promise as extracellular matrix mimics due to their tuneable, fibrous nature. Through incorporation of polar cationic, polar anionic or polar neutral amino acids into the Fmoc-diphenylalanine motif, we show that electrostatic charge plays a key role in the properties of the subsequent gelators. Specifically, we show that an inverse relationship exists for biocompatibility in the solution state versus the gel state for cationic and anionic peptides. Finally, we use tethered bilayer lipid membrane (tBLM) experiments to suggest a likely mode of cytotoxicity for tetrapeptides which exhibit cytotoxicity in the solution state
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