1,354,260 research outputs found
Seismic fragility and risk assessment of large bridge portfolios: efficient mechanical approaches based on multi-source data collection and integration
No full textIn earthquake-prone countries, most of the existing bridges were designed in the past without appropriate anti-seismic regulations and can induce important direct or indirect losses if subjected to severe seismic ground shaking. The main challenges in the extensive seismic risk assessment of existing bridges are related to the large number of structures to be inspected and the limited available resources. Therefore, time- and cost-saving approaches for providing seismic risk metrics on existing bridges are needed. This dissertation investigates efficient methodologies for bridge-specific seismic risk assessment within portfolio analysis by using multi-source data integration and simplified mechanical approaches.
A methodology for multi-source data collection is described. The applicability of remote-sensing data in populating inventory for structural analysis purposes is discussed. A procedure for using Remotely Piloted Aircraft Systems and photogrammetry to retrieve exhaustive structural information is presented.
The effectiveness of displacement-based assessment approaches to be used together with the capacity spectrum method (CSM) for seismic performance assessment is analysed, considering continuous-deck reinforced-concrete (RC) and steel truss multi-span bridges.
A fragility analysis methodology based on cloud analysis using the CSM results is also presented. The CSM is applied with real (i.e. recorded) ground-motion spectra (as opposed to code-based conventional spectra) to explicitly consider record-to-record variability.
A seismic risk assessment framework combining the proposed efficient data collection and simplified probabilistic seismic assessment methodologies is finally presented. It accounts for the influence of knowledge-based uncertainties associated with an initial incomplete data collection. The proposed approach is applied and tested on eight simply-supported RC bridges of the Basilicata national road network
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
DRUG DESIGN, SYNTHESIS AND STRUCTURE-ACTIVITY RELATIONSHIPS OF NOVEL MULTIMODAL INDOLE-FUSED TRICYCLIC DERIVATIVES TARGETING CANNABINOID-MODULATED G PROTEIN-COUPLED RECEPTORS AND CHOLINESTERASES
No full textDue to the multi-factorial nature of most neurological disorders, developing multi-target compounds is still considered among the effective approaches to developing neuroprotective drugs. Despite the scientific advances in the areas of neurochemistry, genetics, molecular and cell biology, there is still no effective treatment available that can delay the onset or slow the progression of neurodegenerative diseases, like Alzheimer’s disease (AD) and memory impairments. In the context of the challenging multitarget-directed-ligand (MTDL) design strategy of novel therapeutic agents for treating AD and related syndromes, progress has been made in the medicinal chemistry of drugs acting within and beyond the endocannabinoid system. Endogenous lipids, such as palmitoylethanolamide, that act simultaneously at GPCRs, ion channels, and PPARs can be taken as templates.
In this Ph.D. thesis study, starting from the structures of small-molecules inhibiting well-established AD-related targets, such as cholinesterases (AChE and BChE) and N-methyl-D-aspartate (NMDA) receptor, the synthesis has been carried out of novel rationally designed tricyclic indole-fused derivatives which interestingly proved to act as modulators (antagonists and/or inverse agonists) of the cannabinoid-related GPCRs GPR18 and GPR55, in some cases endowed with additional BChE-selective inhibition. The desired outcome is the combination of the anticholinesterase activity with the modulation of these poorly studied receptors, for a synergistic effect against neuroinflammation and neurodegeneration. Structure−activity relationships were analyzed, and selectivity versus cannabinoid (CB) and CB-like receptors was assessed. Chemical synthesis and analysis, radioligand binding and functional assays, enzymes’ inhibition kinetics and molecular modeling studies, in addition to allowing us to select candidates for in vivo pharmacological evaluation, provided us with useful medicinal chemistry information enabling the optimization of MTDLs against neurological disorders, potentially more effective than the currently available
Travelling-wave resonant four-wave mixing breaks the limits of cavity-enhanced all-optical wavelength conversion
No full textWave mixing inside optical resonators, while experiencing a large enhancement of the nonlinear interaction efficiency, suffers from strong bandwidth constraints, preventing its practical exploitation for processing broad-band signals. Here we show that such limits are overcome by the new concept of travelling-wave resonant four-wave mixing (FWM). This approach combines the efficiency enhancement provided by resonant propagation with a wide-band conversion process. Compared with conventional FWM in bare waveguides, it exhibits higher robustness against chromatic dispersion and propagation loss, while preserving transparency to modulation formats. Travelling-wave resonant FWM has been demonstrated in silicon-coupled ring resonators and was exploited to realize a 630-μm-long wavelength converter operating over a wavelength range wider than 60 nm and with 28-dB gain with respect to a bare waveguide of the same physical length. Full compatibility of the travelling-wave resonant FWM with optical signal processing applications has been demonstrated through signal retiming and reshaping at 10 Gb s(-1)
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Travelling-wave resonant four-wave mixing on a silicon chip
No full textWe demonstrate that travelling-wave four-wave
mixing in coupled resonators overcomes the bandwidth
limitations of wavelength conversion in single resonators,
preserving the efficiency enhancement: 28-dB gain over silicon
waveguides of the same length is here achieved
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Grating Assisted Coupling in Microring Resonators
No full textGrating Assisted Couplers (GACs) in Silicon-on-Insulator waveguides are studied experimentally as building blocks for optical integrated devices. By including them in a microring resonator configuration, we enhance the GAC wavelength selectivity and limit the resonance range of the microring. This device has the potential for small footprint, highly selective, wavelength filters and sensors
On the Use of Satellite-Based Interferometry for Structural Monitoring of Bridge Portfolios
No full textTransport network management authorities need to address targeted monitoring and structural assessment on appropriately selected critical bridges to improve the serviceability and safety of the network optimising the involved financial budgets and resources. The multi-temporal satellite-based differential interferometry, commonly referred to as MTInSAR, is a remote-sensing technique aimed at detecting displacements of coherent scatterers on the terrestrial surface with centimetre- to millimetre-level accuracy. This paper applies an MTInSAR-based methodology for the portfolio-scale evaluation of deformation phenomena on bridges, suitable for addressing targeted sensor-based monitoring or on-site inspection plans. The methodology is applied to a case-study highway network in Roma (Italy) by using Sentinel-1 (C-band) and COSMO-SkyMed (X-band) satellite datasets. The interferometry products are processed to identify bridge-specific deformation scenarios. The MTInSAR products and the deformation scenarios related to some specific test bridges subjected to subsidence phenomena are analysed to highlight the advantages and disadvantages of the investigated approach
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