628 research outputs found
The radical left's turn towards civil society in Greece: One strategy, two paths
The Communist Party of Greece (KKE) and the Coalition of the Radical Left (SYRIZA) made remarkable ‘turns towards civil society’ over the last decade. It is argued that this was primarily a response aimed at strengthening their social legitimacy, which had reached its lowest point in the early 1990s. Differences in the way the two parties attempted to stabilise and engage their membership and re-establish links to trade unions and new social movements can be attributed to their distinct ideological and organisational legacies. Despite those differences, their respective linkage strategies were both successful until the game-changing 2012 Greek national elections, which brought about the remarkable rise of SYRIZA and the electoral demise of the KKE
Supervised Learning in Spiking Neural Networks with Phase-Change Memory Synapses
Spiking neural networks (SNN) are artificial computational models that have
been inspired by the brain's ability to naturally encode and process
information in the time domain. The added temporal dimension is believed to
render them more computationally efficient than the conventional artificial
neural networks, though their full computational capabilities are yet to be
explored. Recently, computational memory architectures based on non-volatile
memory crossbar arrays have shown great promise to implement parallel
computations in artificial and spiking neural networks. In this work, we
experimentally demonstrate for the first time, the feasibility to realize
high-performance event-driven in-situ supervised learning systems using
nanoscale and stochastic phase-change synapses. Our SNN is trained to recognize
audio signals of alphabets encoded using spikes in the time domain and to
generate spike trains at precise time instances to represent the pixel
intensities of their corresponding images. Moreover, with a statistical model
capturing the experimental behavior of the devices, we investigate
architectural and systems-level solutions for improving the training and
inference performance of our computational memory-based system. Combining the
computational potential of supervised SNNs with the parallel compute power of
computational memory, the work paves the way for next-generation of efficient
brain-inspired systems
Employing surfactant-assisted hydrothermal synthesis to control CuGaO2 nanoparticle formation and improved carrier selectivity of perovskite solar cells
Delafossites like CuGaO2 have appeared as promising p-type semiconductor
materials for opto-electronic applications mainly due to their high optical
transparency and electrical conductivity. However, existing synthetic efforts
usually result in particles with large diameter limiting their performance
relevant to functional electronic applications. In this article, we report a
novel surfactant-assisted hydrothermal synthesis method, which allows the
development of ultrafine (~5 nm) monodispersed p-type CuGaO2 nanoparticles
(NPs). We show that DMSO can be used as a ligand and dispersing solvent for
stabilizing the CuGaO2 NPs. The resulting dispersion is used for the
fabrication of dense, compact functional CuGaO2 electronic layer with
properties relevant to advanced optoelectronic applications. As a proof of
concept, the surfactant-assisted hydrothermal synthesized CuGaO2 is
incorporated as a hole transporting layer (HTL) in the inverted p-i-n
perovskite solar cell device architecture providing improved hole carrier
selectivity and power conversion efficiency compared to conventional PEDOT:PSS
HTL based perovskite solar cells
Paediatric Behçet's disease: a UK tertiary centre experience
There are currently limited data regarding paediatric Behçet's disease (BD), particularly in the UK. We describe the clinical spectrum, treatment and outcome of BD, and explore the relative sensitivities of the criteria for the diagnosis of BD in a UK paediatric cohort. Single retrospective case note review of children with a clinical diagnosis of BD presenting between 1987 and 2012. Demographics, clinical features, treatment and outcomes were recorded. The sensitivities of the International Study Group (ISG) and International Criteria for BD (ICBD) criteria were explored. BD disease activity was calculated using the Behçet's Disease Activity Index (BDAI). Forty-six patients (22 male) were identified. Median age of onset was 4.87 (0.04-15.71) years; median time to diagnosis was 3.74 (0.25-13.48) years. Clinical features were recurrent oral ulceration (97.8 %), recurrent genital ulceration (73.9 %), gastrointestinal (58.7 %), musculoskeletal (47.83 %), cutaneous (23.9 %) involvement and uveitis (2 %). Recurrent genital ulceration was more common in female patients (P = 0.044). Thirty-seven patients (80.4 %) fulfilled the ICBD criteria; only 12 patients (26.1 %) fulfilled the ISG criteria. BDAI score at diagnosis was 7/20 (0-10/20) and significantly decreased to 5/20 (0-9/20) (P < 0.0001) at latest follow-up. The commonest systemic treatment was colchicine (76.1 %); anti-TNFα treatment was reserved for severe cases (15.5 %). Paediatric BD in the UK may present very early in life, sometimes with a family history, and with a low incidence of ocular involvement. Diagnostic delay is common. The majority of our patients required systemic therapy; anti-TNFα was reserved for severe cases and has largely superseded the use of thalidomide
Treatment Strategies for Central Nervous System Effects in Primary and Secondary Haemophagocytic Lymphohistiocytosis in Children
Purpose of Review: This review presents an appraisal of current therapeutic options for the treatment of central nervous system haemophagocytic lymphohistiocytosis (CNS-HLH) in the context of systemic disease, as well as when CNS features occur in isolation. We present the reader with a diagnostic approach to CNS-HLH and commonly used treatment protocols. We discuss and evaluate newer treatments on the horizon. Recent Findings: Mortality is high in patients who do not undergo HSCT, and while larger studies are required to establish benefit in many treatments, a number of new treatments are currently being evaluated. Alemtuzumab is being used as a first-line treatment for CNS-HLH in a phase I/II multicentre prospective clinical trial as an alternative to traditional HLH-1994 and 2004 protocols. It has also been used successfully as a second-line agent for the treatment of isolated CNS-HLH that is refractory to standard treatment. Ruxolitinib and emapalumab are new immunotherapies that block the Janus kinase—Signal Transducer and Activator of Transcription (JAK-STAT) pathway that have shown efficacy in refractory HLH, including for CNS-HLH disease. Summary: Treatment of CNS-HLH often requires HLH-94 or 2004 protocols followed by haematopoietic stem cell transplantation (HSCT) to maintain remission, although relapse can occur, particularly with reduced intensity conditioning if donor chimerism falls. CNS features have been shown to improve or stabilise following HSCT in CNS-HLH in the context of systemic disease and in isolated CNS-HLH. Encouraging reports of early cohort studies suggest alemtuzumab and the Janus kinase (JAK) inhibitor ruxolitinib offer potential salvage therapy for relapsed and refractory CNS-HLH. Newer immunotherapies such as tocilizumab and natalizumab have been shown to be beneficial in sporadic cases. CNS-HLH due to primary gene defects may be amenable to gene therapy in the future
Influence of phytoplankton taxonomic profile on the distribution of total and dissolved dimethylated sulphur (DMSx) species in the North Aegean Sea (Eastern Mediterranean)
The distribution of total and dissolved forms of DMSP and total DMSO was surveyed during two sampling cruises conducted in September 2003 and July 2004 in the North Aegean Sea. During the first cruise the surface concentrations of DMSPt, DMSPd and DMSOt in the coastal group of stations ranged from 20.92 to 23.71 nM, 15.46 to 15.53 nM and 14.90 to 18.73 nM respectively, while in the offshore group the mean concentrations were 27.41 nM (DMSPt) and 14.66 nM (DMSOt). Concerning the phytoplankton assemblage it was dominated by dinoflagellates. During the second cruise, the surface DMSPt, DMSPd and DMSOt concentrations in the coastal group were not significantly changed compared to the first cruise, while the offshore group presented more elevated values (DMSPt: 33.52 nM; DMSPd: 18.78 nM; DMSOt: 36.49 nM). Interestingly the vertical distribution and the phytoplankton abundance in this cruise were changed, with diatoms being the dominant group in the study area. On both cruises statistically significant correlations between small-sized dinoflagellates (≤ 20 μm) as well as coccolithophores and the concentrations of DMSx compounds obtained, suggesting the importance of the above phytoplankton groups in the production and distribution of the these sulphonic forms. At the same time, no significant correlations were observed between DMSx and diatom species. The strong correlation of DMSx species with the group of dinoflagellates coupled with their decorrelation with Chl-a may serve as indirect evidence of heterotrophic forms dominating dinoflagellate taxa thriving in the area during the stratified period.
Interaction of discrete breathers with thermal fluctuations
Discrete breathers (DB) are time-periodic and spatially localized lattice excitations, which can be linearly
stable or unstable with respect to either localized or extended perturbations. We analyze the interaction
of DBs with a thermalized background of small amplitude lattice excitations in a one-dimensional lattice of
Morse oscillators with nearest neighbour interaction. We find that stable DBs are barely influenced by the
thermal noise. Unstable DBs are starting to propagate through the lattice, without loosing their localization
character. The instability can be both due to localized perturbations, as well as due to extended perturbations.
We discuss these observations in terms of resonances of DBs with localized and delocalized perturbations,
and relate them to the issue of DB impact on statistical properties of nonlinear lattices
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