Energy harvesting from railway vibrations - A numerical study based on beam-on-elastic-foundation under quasi-static loading

The objective of this paper is to investigate energy harvesting of train-induced rail vibrations and to provide a comparison between various feasible harvesting locations based on the expected electrical power output. The vibrations of the railway track are modelled using the beam-on-elastic-foundation model under quasi-static loading. The loading applied is from a passenger train moving at a constant velocity. The vibrations of the railway track are then used to determine the energy harvested at each location using one-degree-of-freedom models. The numerical study concludes that the optimal configuration of the harvester is on the rail for the vibration harvester and as a harvesting rail pad between the sleeper and the rail for the compression harvester. The harvested energy with each configurations is O(∼ 10−6) and O(1) J/kg of harvester, respectively.This paper has been carried out under a research project entitled “Framework for Research on Railway Engineering” which is supported by a grant sponsored by Qatar Rail and managed by Qatar University under reference number: QUEX-CENG-Rail 17/18

Visual Working Memory Recruits Two Functionally Distinct Alpha Rhythms in Posterior Cortex

Copyright © 2022 Rodriguez-Larios et al. Oscillatory activity in the human brain is dominated by posterior alpha oscillations (8–14 Hz), which have been shown to be functionally relevant in a wide variety of cognitive tasks. Although posterior alpha oscillations are commonly considered a single oscillator anchored at an individual alpha frequency (∼10 Hz), previous work suggests that individual alpha frequency reflects a spatial mixture of different brain rhythms. In this study, we assess whether independent component analysis (ICA) can disentangle functionally distinct posterior alpha rhythms in the context of visual short-term memory retention. Magnetoencephalography (MEG) was recorded in 33 subjects while performing a visual working memory task. Group analysis at sensor level suggested the existence of a single posterior alpha oscillator that increases in power and decreases in frequency during memory retention. Conversely, single-subject analysis of independent components revealed the existence of two dissociable alpha rhythms: one that increases in power during memory retention (Alpha1) and another one that decreases in power (Alpha2). Alpha1 and Alpha2 rhythms were differentially modulated by the presence of visual distractors (Alpha1 increased in power while Alpha2 decreased) and had an opposite relationship with accuracy (positive for Alpha1 and negative for Alpha2). In addition, Alpha1 rhythms showed a lower peak frequency, a narrower peak width, a greater relative peak amplitude and a more central source than Alpha2 rhythms. Together, our results demonstrate that modulations in posterior alpha oscillations during short-term memory retention reflect the dynamics of at least two distinct brain rhythms with different functions and spatiospectral characteristics.The Netherlands Organisation for Scientific Research (NWO) Vidi Grant 016.Vidi.185.137; National Institutes of Health Grant R01-MH123679

Neoadjuvant chemotherapy versus primary surgery in advanced ovarian carcinoma

BACKGROUND: Patients with advanced ovarian cancer should be treated by radical debulking surgery aiming at complete tumor resection. Unfortunately about 70% of the patients present with advanced disease, when optimal debulking can not be obtained, and therefore these patients gain little benefit from surgery. Neoadjuvant chemotherapy (NACT) has been proposed as a novel therapeutic approach in such cases. In this study, we report our results with primary surgery or neoadjuvant chemotherapy as treatment modalities in the specific indication of operable patients with advanced ovarian carcinoma (no medical contraindication to debulking surgery). PATIENTS AND METHODS: A total of 59 patients with stage III or IV epithelial ovarian carcinomas were evaluated between 1998 and 2003. All patients were submitted to surgical exploration aiming to evaluate tumor resectability. Neoadjuvant chemotherapy was given (in 27 patients) where optimal cytoreduction was not feasible. Conversely primary debulking surgery was performed when we considered that optimal cytoreduction could be achieved by the standard surgery (32 patients). RESULTS: Optimal cytoreduction was higher in the NACT group (72.2%) than the conventional group (62.4%), though not statistically significant (P = 0.5). More important was the finding that parameters of surgical aggressiveness (blood loss rates, ICU stay and total hospital stay) were significantly lower in NACT group than the conventional group. The median overall survival time was 28 months in the conventional group and 25 months in NACT group with a P value of 0.5. The median disease free survival was 19 months in the conventional group and 21 months in NACT group (P = 0.4). In multivariate analysis, the pathologic type and degree of debulking were found to affect the disease free survival significantly. Overall survival was not affected by any of the study parameters. CONCLUSION: Primary chemotherapy followed by interval debulking surgery in select group of patients doesn't appear to worsen the prognosis, but it permits a less aggressive surgery to be performed

Soft Sensor for NOx Emission using Dynamical Neural Network

In this paper we propose a soft sensor for prediction of NOx emission from the combustion unit of industrial boilers. The soft sensor is based on a dynamical neural network model. A simplified structure of the dynamical neural network model is achieved by grouping the input variables using basic knowledge of the system. Neural network model is trained using real data logs of an industrial boiler. Principal Component Analysis (PCA) is used to reduce number of input variables. Lag space for the model is found by using genetic algorithm to find the best time delayed model. Lag space obtained from the linear model is then used for constriction of the dynamical neural network. The proposed model is validated using different data from the same boiler and its ability to accurately predict NOx emission from the boiler is demonstrated

QAPgrid: A Two Level QAP-Based Approach for Large-Scale Data Analysis and Visualization

Background: The visualization of large volumes of data is a computationally challenging task that often promises rewarding new insights. There is great potential in the application of new algorithms and models from combinatorial optimisation. Datasets often contain “hidden regularities” and a combined identification and visualization method should reveal these structures and present them in a way that helps analysis. While several methodologies exist, including those that use non-linear optimization algorithms, severe limitations exist even when working with only a few hundred objects. Methodology/Principal Findings: We present a new data visualization approach (QAPgrid) that reveals patterns of similarities and differences in large datasets of objects for which a similarity measure can be computed. Objects are assigned to positions on an underlying square grid in a two-dimensional space. We use the Quadratic Assignment Problem (QAP) as a mathematical model to provide an objective function for assignment of objects to positions on the grid. We employ a Memetic Algorithm (a powerful metaheuristic) to tackle the large instances of this NP-hard combinatorial optimization problem, and we show its performance on the visualization of real data sets. Conclusions/Significance: Overall, the results show that QAPgrid algorithm is able to produce a layout that represents the relationships between objects in the data set. Furthermore, it also represents the relationships between clusters that are feed into the algorithm. We apply the QAPgrid on the 84 Indo-European languages instance, producing a near-optimal layout. Next, we produce a layout of 470 world universities with an observed high degree of correlation with the score used by the Academic Ranking of World Universities compiled in the The Shanghai Jiao Tong University Academic Ranking of World Universities without the need of an ad hoc weighting of attributes. Finally, our Gene Ontology-based study on Saccharomyces cerevisiae fully demonstrates the scalability and precision of our method as a novel alternative tool for functional genomics

An international collaborative evaluation of central serous chorioretinopathy: different therapeutic approaches and review of literature. The European Vitreoretinal Society central serous chorioretinopathy study

Purpose: To study and compare the efficacy of different therapeutic options for the treatment of central serous chorioretinopathy (CSCR). Methods: This is a nonrandomized, international multicentre study on 1719 patients (1861 eyes) diagnosed with CSCR, from 63 centres (24 countries). Reported data included different methods of treatment and both results of diagnostic examinations [fluorescein angiography and/or optical coherent tomography (OCT)] and best-corrected visual acuity (BCVA) before and after therapy. The duration of observation had a mean of 11 months but was extended in a minority of cases up to 7 years. The aim of this study is to evaluate the efficacy of the different therapeutic options of CSCR in terms of both visual (BCVA) and anatomic (OCT) improvement. Results: One thousand seven hundred nineteen patients (1861 eyes) diagnosed with CSCR were included. Treatments performed were nonsteroidal anti-inflammatory eye drops, laser photocoagulation, micropulse diode laser photocoagulation, photodynamic therapy (PDT; Standard PDT, Reduced-dose PDT, Reduced-fluence PDT), intravitreal (IVT) antivascular endothelial growth factor injection (VEGF), observation and other treatments. The list of the OTHERS included both combinations of the main proposed treatments or a variety of other treatments such as eplerenone, spironolactone, acetazolamide, beta-blockers, anti-anxiety drugs, aspirin, folic acid, methotrexate, statins, vitis vinifera extract medication and pars plana vitrectomy. The majority of the patients were men with a prevalence of 77%. The odds ratio (OR) showed a partial or complete resolution of fluid on OCT with any treatment as compared with observation. In univariate analysis, the anatomical result (improvement in subretinal fluid using OCT at 1 month) was favoured by age <60 years (p < 0.005), no previous observation (p < 0.0002), duration less than 3 months (p < 0.0001), absence of CSCR in the fellow eye (p = 0.04), leakage outside of the arcade (p = 0.05) and fluid height >500 \u3bcm (p = 0.03). The OR for obtaining partial or complete resolution showed that anti-VEGF and eyedrops were not statistically significant; whereas PDT (8.5), thermal laser (11.3) and micropulse laser (8.9) lead to better anatomical results with less variability. In univariate analysis, the functional result at 1 month was favoured by first episode (p = 0.04), height of subretinal fluid >500 \u3bcm (p < 0.0001) and short duration of observation (p = 0.02). Finally, there was no statistically significant difference among the treatments at 12 months. Conclusion: Spontaneous resolution has been described in a high percentage of patients. Laser (micropulse and thermal) and PDT seem to lead to significant early anatomical improvement; however, there is little change beyond the first month of treatment. The real visual benefit needs further clarification