216 research outputs found

    Data driven approach to sparsification of reaction diffusion complex network systems

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    Graph sparsification is an area of interest in computer science and applied mathematics. Sparsification of a graph, in general, aims to reduce the number of edges in the network while preserving specific properties of the graph, like cuts and subgraph counts. Computing the sparsest cuts of a graph is known to be NP-hard, and sparsification routines exists for generating linear sized sparsifiers in almost quadratic running time O(n2+ϵ)O(n^{2 + \epsilon}). Consequently, obtaining a sparsifier can be a computationally demanding task and the complexity varies based on the level of sparsity required. In this study, we extend the concept of sparsification to the realm of reaction-diffusion complex systems. We aim to address the challenge of reducing the number of edges in the network while preserving the underlying flow dynamics. To tackle this problem, we adopt a relaxed approach considering only a subset of trajectories. We map the network sparsification problem to a data assimilation problem on a Reduced Order Model (ROM) space with constraints targeted at preserving the eigenmodes of the Laplacian matrix under perturbations. The Laplacian matrix (L=DAL = D - A) is the difference between the diagonal matrix of degrees (DD) and the graph's adjacency matrix (AA). We propose approximations to the eigenvalues and eigenvectors of the Laplacian matrix subject to perturbations for computational feasibility and include a custom function based on these approximations as a constraint on the data assimilation framework. We demonstrate the extension of our framework to achieve sparsity in parameter sets for Neural Ordinary Differential Equations (neural ODEs)

    Reinforcing POD-based model reduction techniques in reaction-diffusion complex networks using stochastic filtering and pattern recognition

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    Complex networks are used to model many real-world systems. However, the dimensionality of these systems can make them challenging to analyze. Dimensionality reduction techniques like POD can be used in such cases. However, these models are susceptible to perturbations in the input data. We propose an algorithmic framework that combines techniques from pattern recognition (PR) and stochastic filtering theory to enhance the output of such models. The results of our study show that our method can improve the accuracy of the surrogate model under perturbed inputs. Deep Neural Networks (DNNs) are susceptible to adversarial attacks. However, recent research has revealed that Neural Ordinary Differential Equations (neural ODEs) exhibit robustness in specific applications. We benchmark our algorithmic framework with the neural ODE-based approach as a reference.Comment: 19 pages, 6 figure

    A Web-based GIS for Tourism Administration in Kerala

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    Geographic  Information  systems  are  used  widely  for Tourism  administration  in  several  countries,  but  not especially true in Kerala scenario. This paper attempts to present a GIS model for tourism administration in Kerala. Various  applications  of  Tourism  based  GIS  in  the international  arena  have  been  examined  in  this  paper. Data collected from different sources reveals the present status of Tourism GISs world over. The study focuses on areas where GIS can be applied in Kerala Tourism and gives outputs that can be generated using the proposed model.  Tourism  is  essentially  a  cartographic phenomenon.  In  this  context  this  paper  assumes importance as various devices, both wired and wireless are  increasingly  used  to  accesses  cartographic information.  With  internet  becoming  an  unavoidable component of modern day life, map based information is the need of the hour. A web based GIS will benefit Kerala tourism in the coming years. The model proposed in this paper can act as a foundation for building a web based GIS for Kerala tourism

    π-extended peri-acenes: recent progress in synthesis and characterization

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    Nanographenes (NGs) with open-shell character have gained intense attention due to their potential applications in future organic nanoelectronics and spintronics. Among them, NGs bearing a pair of parallel zigzag edges, such as acenes and peri-acenes (PAs) bestow unique (opto)electronic and magnetic properties owing to their localized non-bonding π-state. However, their reactive zigzag edges impart intrinsic instability, leading to the challenging synthesis. The recent development of synthetic strategies provided access to several π-extended PAs, which were considered unrealistic for decades. Notably, their laterally π-extended structures of zigzag-edged graphene nanoribbons was realised via on-surface synthesis. However, synthesis of π-extended PAs in solution is still in its infancy, more intensive scientific efforts are needed to surpass the existing challenges regarding stability and solubility. This Review provides an overview of recent progress in the synthesis and characterization of PAs through a bottom-up synthetic strategy, including on-surface and solution-phase chemistry. In addition, views on existing challenges and the future prospects are also provided

    A surface confined yttrium(III) bis-phthalocyaninato complex: a colourful switch controlled by electrons

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    AMs of a Y(III) double-decker complex on ITO have been prepared and their electrical and optical properties explored, exhibiting three accessible stable redox states with characteristic absorption bands in the visible spectra, corresponding to three complementary colors (i.e., green, blue and red). These absorption bands are exploited as output signals of this robust ternary electrochemical switch, behaving hence as an electrochromic molecular-based device.This work was funded by ERC StG 2012-306826 e-GAMES, the EU project ITN iSwitch (GA no. 642196), the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), DGI (Spain) BE-WELL CTQ2013-40480-R, and Generalitat de Catalunya 2014-SGR-17. I. A. acknowledges CIBER-BBN for a grant.Peer reviewe

    Light interception and yield response of cotton varieties to high density planting and fertilizers in sub-tropical India

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    Plant density and optimum fertilization are two important agronomic practices to enhance productivity of cotton (Gossypium hirsutum L.) varieties. The objective of this study was to investigate the effect of high density planting (HDPS) and fertilization rate, especially their interactions, on yield, yield components of cotton varieties in sub-tropical India. Split-split plot design was adopted and replicated thrice. The main plots were assigned to low, medium and high plant densities (16.7, 13.3 and 11.1 plants/m2). Pre released cotton varieties TCH-1705 and LH-2298 were tested in low, moderate and high rates of fertilizers recommended for the region (100, 125 and 150 %) in sub-sub plots. Significantly higher seed cotton yield (1148 kg/ha) was achieved in narrow inter row spaced at 60 cm over normal plant row spacing of 90 cm (1025 kg/ha). Compact genotype TCH-1705 was out yielded (1146 kg/ha) over LH 2298(1044 kg/ha). Application of fertilizers at higher rate improved seed cotton yield (1232 kg/ha) Leaf area index (3.8) and light interception (0.98) over blanket recommendation. The results of the study inferred that seed cotton yield improvement was possible under HDPS production system with compact varieties grown at narrow spacing and higher fertilizer dose

    Modified planting geometry and fertilizer rate on productivity of corn (Zea mays L.) in Vertisols

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    A field experiment was conducted at Raichur, Karnataka with an objective to find out production potential of grain corn planted in clumps and rate of fertilizer application. Design followed was split plot and repeated thrice with rate of fertilizer application as main factor and planting geometry as sub factor. Treatments consists of planting corn at 2, 3, 4 seeds/hill compared with single seeds/hill (60 cm x 20 cm) and farmers practice uneven spacing. In clumped plants inter row spacing is similar (60 cm) and intra row distance is differ to maintain uniform plant density (83,333 plants/ha) in each treatment. Recommended dose of fertilizers (RDF) was applied in 2 splits and 150% RDF in 3 splits. Results revealed that planting 2 seeds /hill at 60 cm x 40 cm recorded significantly higher yield, economics of corn as compared to 3 and 4 seeds/hill and farmers practice. As increased plant population per hill maintains higher soil moisture at 75 days after planting (7.5-9.4%) and lower dry matter per plant at harvest (236.3 to 185.5 g) as compared to conventional planting. Application of higher (150%) fertilizers in 3 splits recorded higher dry matter production, grain yield, and economic returns over RDF. This may be useful strategy for corn productivity enhancement by clump planting with higher fertilizer rate

    Survival and quality of life analysis in glioblastoma multiforme with adjuvant chemoradiotherapy: a retrospective study

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    Background: Glioblastoma multiforme (GBM) is the most common and aggressive primary intracranial tumor. Despite modern therapies, it is still fatal with tremendously poor prognosis with a median survival of 14 months. Even though mean survival and progression-free survival (PFS) are considered as primary response measure, it is important to assess the effects of therapies on disease burden and health-related quality of life (HRQoL). Changes in quality of life (QoL) indicates the impact of cytotoxic therapy and may aid in defining response in the absence of quantifiable endpoints like tumor regression. The objective was to assess 2-year survival and quality of life in GBM patients who underwent primary surgery followed by chemo-radiotherapy and 6-month adjuvant chemotherapy with temozolomide.  Materials and methods: Single-institution retrospective study of 60 patients of GBM from 2015 to 2017. Data regarding patient factors, disease factors, and treatment factors were collected and survival was calculated. Results: 60 patients with GBM were analyzed, male to female ratio was 1.6:1. Patients most commonly presented with headache. Most common tumour site is the frontal lobe. The median overall survival (OS) was 10 months. The 1-year and 2-year survival rates were 30% and 6.7%, respectively. Compared to before surgery patients have showed improved emotional, social and role functioning in Post radiotherapy period. There was a decrease in symptoms like pain, headache and seizures. Conclusions: OS and QoL in GBM patients remains poor despite constant research and studies. Maximum safe resection followed by adjuvant temozolomide has shown improvement in OS. Post-surgery and adjuvant radiotherapy patients have shown a decrease in symptoms and better QoL

    A Rapid, Low-Cost, and Scalable Technique for Printing State-of-the-Art Organic Field-Effect Transistors

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    In the last few years exciting advances have been achieved in developing printing techniques for organic semiconductors, and impressive mobility values have been reported for the resulting organic field-effect transistors (OFETs). However, not all these techniques are scalable and some of them require additional crystallization steps. This study reports on the fabrication of OFETs employing blends of four benchmark organic semiconductors with polystyrene and demonstrates that applying the same formulation and experimental conditions for printing them, highly reproducible and uniform crystalline films exhibiting high OFET performance are successfully achieved. It is noted that the mobility values achieved here are not the highest reported for the studied materials; however, they are state-of-the-art values and could be regarded as exceptional considering the low cost and fast speed of the fabrication process involved here.This work was mainly funded by the ERC StG 2012 306826 e GAMES and ERC PoC 2014 640120 LAB TECH projects. The authors also thank the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER BBN), the DGI (Spain) project BE WELL CTQ2013 40480 R, the Generalitat de Catalunya (2014 SGR 17) and the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV 2015 0496). The authors would like to thank the ICTS "NANBIOSIS", more specifically to the Nanotechnology Platform, unit of CIBER BBN at the Institute for Bioengineering of Catalonia (IBEC) for their assistance in ToF SIMS analyses. I. T. acknowledges FPU fellowship from the Ministery and the Materials Science PhD Program of Universitat Autònoma de Barcelona. F. G. D. P. thanks Universidad Técnica de Ambato and Secretaría de Educación Superior, Ciencia, Tecnología e Innovación for funding through a doctoral scholarship “Convocatoria abierta 2010”.Peer reviewe
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