660 research outputs found
Least weight and least cost optimisation of a passenger vessel
In the scantling design of a passenger ship, minimum production costminimum weight and maximum moment of inertia (stiffness) are conflicting objectives. For that purpose, recent improvements have been made to the LBR-5 software (French acronym of Stiffened Panels Software”, version 5.0) to optimize the scantling of ship sections by considering production cost, weight and moment of inertia in the optimisation objective function. A real multi-criterion optimisation of a passenger ship is presented in this paper. Results highlight that LBR-5 is competitive software to optimise scantling of ships at very early design stage with management of critical problems studied normally at a later step of the design
Multi-criterion scantling optimisation of cruise ships
A numerical tool for the optimisation of the scantlings of a ship is extended by considering production cost, weight and moment of iner tia in the objective function. A multi-criteria optimisation of a passenger ship is conducted to illustrate the analysis process. Pareto frontiers are obtained and results are verified with Bureau Veritas rules
Coronary flow reserve in stress-echo lab. From pathophysiologic toy to diagnostic tool
The assessment of coronary flow reserve by transthoracic echocardiography has recently been introduced into clinical practice with gratifying results for the diagnosis of left anterior descending artery disease simultaneously reported by several independent laboratories. This technological novelty is changing the practice of stress echo for 3 main reasons. First, adding coronary flow reserve to regional wall motion allows us to have – in the same sitting – high specificity (regional wall motion) and a high sensitivity (coronary flow reserve) diagnostic marker, with an obvious improvement in overall diagnostic accuracy. Second, the technicalities of coronary flow reserve shift the balance of stress choice in favour of vasodilators, which are a more robust hyperemic stress and are substantially easier to perform with dual imaging than dobutamine or exercise. Third, the coronary flow reserve adds a quantitative support to the exquisitely qualitative assessment of wall motion analysis, thereby facilitating the communication of stress echo results to the cardiological world outside the echo lab. The next challenges involve the need to expand the exploration of coronary flow reserve to the right and circumflex coronary artery and to prove the additional prognostic value – if any – of coronary flow reserve over regional wall motion analysis, which remains the cornerstone of clinically-driven diagnosis in the stress echo lab
Saccades and smooth pursuit eye movements in central vertigo
In order to analyze the diagnostic efficiency of saccadic and pursuit eye movements compared to findings from brain magnetic resonance imaging in patients with central vertigo, 108 patients were selected from 580 dizzy patients as cases of suspected central origin; the saccadic and pursuit eye movements were evaluated by electronystagmography and findings were compared to information from magnetic resonance imaging. The study of oculomotor movements in patients suspected of having a central lesion revealed a 83.3% sensitivity and 21.2% specificity. Restricting consideration to severe alterations in eye movements as indicative of a central origin, this test gives a 71.4% sensitivity and 50.0% specificity. In conclusion, the study of alterations in oculomotor movements, in patients with suspected central lesions, proved to be a test with good sensitivity also compared with results of magnetic resonance imaging
Farm-wide virtual load monitoring for offshore wind structures via Bayesian neural networks
Offshore wind structures are subject to deterioration mechanisms throughout
their operational lifetime. Even if the deterioration evolution of structural
elements can be estimated through physics-based deterioration models, the
uncertainties involved in the process hurdle the selection of lifecycle
management decisions. In this scenario, the collection of relevant information
through an efficient monitoring system enables the reduction of uncertainties,
ultimately driving more optimal lifecycle decisions. However, a full monitoring
instrumentation implemented on all wind turbines in a farm might become
unfeasible due to practical and economical constraints. Besides, certain load
monitoring systems often become defective after a few years of marine
environment exposure. Addressing the aforementioned concerns, a farm-wide
virtual load monitoring scheme directed by a fleet-leader wind turbine offers
an attractive solution. Fetched with data retrieved from a fully-instrumented
wind turbine, a model can be trained and then deployed, thus yielding load
predictions of non-fully monitored wind turbines, from which only standard data
remains available. In this paper, we propose a virtual load monitoring
framework formulated via Bayesian neural networks (BNNs) and we provide
relevant implementation details needed for the construction, training, and
deployment of BNN data-based virtual monitoring models. As opposed to their
deterministic counterparts, BNNs intrinsically announce the uncertainties
associated with generated load predictions and allow to detect inaccurate load
estimations generated for non-fully monitored wind turbines. The proposed
virtual load monitoring is thoroughly tested through an experimental campaign
in an operational offshore wind farm and the results demonstrate the
effectiveness of BNN models for fleet-leader-based farm-wide virtual
monitoring
Regulation of the ESC transcriptome by nuclear long non-coding RNAs
Long noncoding (lnc)RNAs have recently emerged as key regulators of gene expression. Here, we performed high-depth poly(A)+ RNA sequencing across multiple clonal populations of mouse embryonic stem cells (ESCs) and neural progenitor cells (NPCs) to comprehensively identify differentially regulated lncRNAs. We establish a biologically robust profile of lncRNA expression in these two cell types and further confirm that the majority of these lncRNAs are enriched in the nucleus. Applying weighted gene co-expression network analysis, we define a group of lncRNAs that are tightly associated with the pluripotent state of ESCs. Among these, we show that acute depletion of PAT-14 using antisense oligonucleotides impacts the differentiation- and development-associated gene expression program of ESCs. Furthermore, we demonstrate that Firre, a lncRNA highly enriched in the nucleoplasm and previously reported to mediate chromosomal contacts in ESCs, controls a network of genes related to RNA processing. Together, we provide a comprehensive, up-to-date and high resolution compilation of lncRNA expression in ESCs and NPCs and show that nuclear lncRNAs are tightly integrated into the regulation of ESC gene expression
Estabelecimento do Panicum maximum cv. Massai em função de doses crescentes de nitrogênio.
Objetivo: encontrar uma combinação eficiente, entre dose de fertilizzação nitrogenada e idade da palnta que permita boa produção de massa com menor lignificação, pode ajudar no manejo dessa importante forrageira.bitstream/item/104640/1/Estabelecimento-do-Panicum-maximum-cv.pd
ERDA/Lewis research center photovoltaic systems test facility
A national photovoltaic power systems test facility (of initial 10-kW peak power rating) is described. It consists of a solar array to generate electrical power, test-hardware for several alternate methods of power conversion, electrical energy storage systems, and an instrumentation and data acquisition system
Human coronary inflammation by computed tomography: Relationship with coronary microvascular dysfunction
Background A new imaging metric using coronary computed tomography angiography (CCTA), addressing the peri-coronary adipose tissue (PCAT) computed tomography (CT) attenuation, has been clinically validated. This method provides information regarding coronary inflammation. It is unclear how coronary inflammation affects microvascular function. The non-invasive evaluation of coronary flow velocity reserve is widely used in clinical practice using Doppler measurement on the left anterior descending coronary artery (CFVR-lad) during stress-echocardiography (SE). We hypothesize that coronary inflammation affects CFVR-lad and, in the absence of overt CAD, they are significantly correlated. Methods We evaluated the relationship between coronary inflammation (by PCAT CT attenuation) and coronary microvascular function (by CFVR-lad) in subjects with no or non-obstructive (diameter stenosis <70%) coronary artery disease (CAD). Results Two-hundred and two subjects were enrolled in the study. The relationship between PCAT CT attenuation and CFVR-lad show a significant inverse relationship in the entire group of subjects enrolled in the study (r = −0.32, p < 0.001). Correlation between PCAT CT attenuation and CFVR-lad was significant in subjects with no or mild CAD-lad, while this was not the case in subjects with intermediate CAD-lad. The R and R2 were respectively −0.40, −0.16 in subjects without CAD (p < 0.001) and − 0.35 and − 0.12 in subjects with mild CAD-lad (p = 0.001). Conclusions The main finding of the current study is the independent relationship between coronary microvascular function, by Doppler CFVR-lad during SE, in subjects without severely obstructive CAD in the left anterior descending coronary artery, and the level of local coronary inflammation, by PCAT attenuation measurement on CCTA
'SOSORT consensus paper on brace action: TLSO biomechanics of correction (investigating the rationale for force vector selection)'
BACKGROUND: The effectiveness of orthotic treatment continues to be controversial in international medical literature due to differences in the reported results and conclusions of various studies. Heterogeneity of the samples has been suggested as a reason for conflicting results. Besides the obvious theoretical differences between the brace concepts, the variability in the technical factors can also explain the contradictory results between same brace types. This paper will investigate the degree of variability among responses of scoliosis specialists from the Brace Study Ground of the International Society on Scoliosis Orthopedic and Rehabilitation Treatment SOSORT. Ultimately, this information could be a foundation for establishing a consensus and framework for future prospective controlled studies. METHODS: A preliminary questionnaire on the topic of 'brace action' relative to the theory of three-dimensional scoliosis correction and brace treatment was developed and circulated to specialists interested in the conservative treatment of adolescent idiopathic scoliosis. A particular case was presented (main thoracic curve with minor lumbar). Several key points emerged and were used to develop a second questionnaire which was discussed and full filed after the SOSORT consensus meeting (Milano, Italy, January 2005). RESULTS: Twenty-one questionnaires were completed. The Chêneau brace was the most frequently recommended. The importance of the three point system mechanism was stressed. Options about proper pad placement on the thoracic convexity were divided 50% for the pad reaching or involving the apical vertebra and 50% for the pad acting caudal to the apical vertebra. There was agreement about the direction of the vector force, 85% selecting a 'dorso lateral to ventro medial' direction but about the shape of the pad to produce such a force. Principles related to three-dimensional correction achieved high consensus (80%–85%), but suggested methods of correction were quite diverse. CONCLUSION: This study reveals that among participating SOSORT specialists there continues to be a strongly held and conflicting if not a contentious opinion regarding brace design and treatment. If the goal of a 'treatment consensus' is realistic and achievable, significantly more effort will be required to reconcile these differences
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