Abstract
This paper presents a novel hybrid model integrating maximal overlap discrete wavelet transform (MODWT) denoising and empirical mode decomposition (EMD) with sequence‐to‐sequence (seq2seq) ...long short‐term memory (LSTM) neural networks for day‐ahead electricity price forecasting. The nonstationary and nonlinear time series electricity price data are first denoised using MODWT. The resulting signal is decomposed into several intrinsic mode functions (IMF) with different resolutions by EMD. The extracted IMF is then introduced into seq2seq LSTM to obtain an aggregated predicted value for electricity price. The proposed method is examined using the Nord pool Elspot energy market data. Empirical results show that the proposed model outperformed the other forecasting models like LSTM and stacked LSTM. The performance measures indicate that data denoising can significantly improve the prediction stability and the generalization ability of the LSTM model.
Many marine invertebrates have larval stages covered in linear arrays of beating cilia, which propel the animal while simultaneously entraining planktonic prey1. These bands are strongly conserved ...across taxa spanning four major superphyla2, 3, and they are responsible for the unusual morphologies of many invertebrate larvae4, 5. However, few studies have investigated their underlying hydrodynamics6, 7. Here, we study the ciliary bands of starfish larvae, and discover a beautiful pattern of slowly evolving vortices that surrounds the swimming animals. Closer inspection of the bands reveals unusual ciliary 'tangles' analogous to topological defects that break up and re-form as the animal adjusts its swimming stroke. Quantitative experiments and modelling demonstrate that these vortices create a physical trade-off between feeding and swimming in heterogeneous environments, which manifests as distinct flow patterns or 'eigenstrokes' representing each behaviour--potentially implicating neuronal control of cilia. This quantitative interplay between larval form and hydrodynamic function may generalize to other invertebrates with ciliary bands, and illustrates the potential effects of active boundary conditions in other biological and synthetic systems.
We study a generalization of the setting of regenerating codes, motivated by applications to storage systems consisting of clusters of storage nodes. There are <inline-formula> <tex-math ...notation="LaTeX">n </tex-math></inline-formula> clusters in total, with <inline-formula> <tex-math notation="LaTeX">m </tex-math></inline-formula> nodes per cluster. A data file is coded and stored across the <inline-formula> <tex-math notation="LaTeX">mn </tex-math></inline-formula> nodes, with each node storing <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula> symbols. For availability of data, we require that the file be retrievable by downloading the entire content from any subset of <inline-formula> <tex-math notation="LaTeX">k </tex-math></inline-formula> clusters. Nodes represent entities that can fail. We distinguish between intra-cluster and inter-cluster bandwidth (BW) costs during node repair. Node-repair in a cluster is accomplished by downloading <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula> symbols each from any set of <inline-formula> <tex-math notation="LaTeX">d </tex-math></inline-formula> other clusters, dubbed remote helper clusters, and also up to <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula> symbols each from any set of <inline-formula> <tex-math notation="LaTeX">\ell </tex-math></inline-formula> surviving nodes, dubbed local helper nodes, in the host cluster. We first identify the optimal trade-off between storage-overhead and inter-cluster repair-bandwidth under functional repair, and also present optimal exact-repair code constructions for a class of parameters. The new trade-off is strictly better than what is achievable via space-sharing existing coding solutions, whenever <inline-formula> <tex-math notation="LaTeX">\ell > 0 </tex-math></inline-formula>. We then obtain sharp lower bounds on the necessary intra-cluster repair BW to achieve optimal trade-off. Under functional repair, random linear network codes (RLNCs) simultaneously optimize usage of both inter- and intra-cluster repair BW; simulation results based on RLNCs suggest optimality of the bounds on intra-cluster repair-bandwidth. Our bounds reveal the interesting fact that, while it is beneficial to increase the number of local helper nodes <inline-formula> <tex-math notation="LaTeX">\ell </tex-math></inline-formula> in order to improve the storage-vs-inter-cluster-repair-BW trade-off, increasing <inline-formula> <tex-math notation="LaTeX">\ell </tex-math></inline-formula> not only increases intra-cluster BW in the host-cluster, but also increases the intra-cluster BW in the remote helper clusters. We also analyze resilience of the clustered storage system against passive eavesdropping by providing file-size bounds and optimal code constructions.
The prophetic warning by the Nobel Laureate Joshua Lederberg1 that “the microbe that felled one child in a distant continent can reach yours today and seed a global pandemic tomorrow” has once again ...proved its relevance with the emergence of coronavirus disease 2019 (COVID-19) as the latest pandemic that is affecting human health and economy across the world. Both World Trade Organization (WTO) and Organization for Economic Cooperation and Development (OECD) have indicated COVID-19 pandemic as the biggest threat to global economy since the financial crisis of 2008-2009. Post-script: Within a week of submitting this manuscript for publication the situation both in respect to health and economy, has rapidly deteriorated globally. ...as per latest information (WHO coronavirus disease 2019 (COVID-19) Situation Report - 59) the infection has spread to 147 countries, involving over 0.2 million individuals and resulting in over 8,000 deaths.
Due to the rapid depletion of natural resources and undesired environmental changes in a global scale, it is necessary to conserve the natural resources and protect the environment. Industries which ...manufacture plastic based products have the necessity to recycle plastics. There are number of methods to recycle plastics. Since the selection of the best recycling method involves complex decision variables, it is considered to be a multiple criteria decision-making (MCDM) problem. This article develops an evaluation model based on the fuzzy Analytic Hierarchy Process (AHP) and the technique for order performance by similarity to ideal solution (TOPSIS) to enable the industry practitioners to perform performance evaluation in a fuzzy environment. The purpose of the study is to determine the best method for recycling plastics among the various plastic recycling processes. By observing the results, it is identified that mechanical recycling process is found to be the best plastic recycling process using the integrated approach.
We consider a communication problem in which an update of the source message needs to be conveyed to one or more distant receivers that are interested in maintaining specific linear functions of the ...source message. The setting is one in which the updates are sparse in nature, and where neither the source nor the receiver(s) is aware of the exact difference vector , but only know the amount of sparsity that is present in the difference vector. Under this setting, we are interested in devising linear encoding and decoding schemes that minimize the communication cost involved. We show that the optimal solution to this problem is closely related to the notion of maximally recoverable codes (MRCs), which were originally introduced in the context of coding for storage systems. In the context of storage, MRCs guarantee optimal erasure protection when the system is partially constrained to have local parity relations among the storage nodes. In our problem, we show that optimal solutions exist if and only if MRCs of certain kind (identified by the desired linear functions) exist. We consider point-to-point and broadcast versions of the problem and identify connections to MRCs under both these settings. For the point-to-point setting, we show that our linear-encoder-based achievable scheme is optimal even when non-linear encoding is permitted. The theory is illustrated in the context of updating erasure coded storage nodes. We present examples based on modern storage codes, such as the minimum bandwidth regenerating codes.
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•Studied effect of homotypic and heterotypic crowding on fibril rate and stability.•In mixed crowders fibril rate is comparable or slower than the individual crowders.•Crowders ...stabilize lysozyme and induce two-state unfolding at higher concentration.•Stability or fibril rate is not correlated with size or viscosity of the crowders.•Excluded volume and direct interactions contribute to changes induced by crowders.
Ionic liquids (ILs) are neoteric solvents with a wide range of applications. Interaction of ILs with proteins alters their stability and self-aggregation. The present work analyses the effect of ...hydrophobic interactions between protein and ILs using lysozyme (Lyz) and methylimidazolium-ILs with the side-chain substitutions of H (MIC), ethyl (EMIC), butyl (BMIC), hexyl (HMIC), and octyl (OMIC) groups. Below 100 mM, ILs decrease the rate of fibrillation, with MIC showing the largest reduction. Above 100 mM, the rate is sharply increased; however, a further increase in the concentration reduces the rate. Also, the fibrillation mechanism is shifted from nucleation-independent polymerization to a nucleation-dependent mechanism with a measurable lag phase, except in MIC. Above 200 mM, HMIC increases the apparent fibrillation time nearly 55-fold and OMIC inhibits the fibrillation. Spectroscopic and docking studies suggest that the binding affinities are such that OMIC > HMIC > BMIC EMIC MIC. Thermal denaturation experiments predict that at lower concentrations (≤20 mM) the destabilization by MIC is greater, whereas at higher concentrations the destabilizing effect increases for ILs with longer alkyl chains. Overall, the results suggest that increasing the hydrophobicity of the IL increases its binding affinity with Lyz, which decreases the thermal stability and fibrillation propensity of the protein.
Imidazolium ionic liquids with longer alkyl side chains show a larger destabilization effect on lysozyme. Increased hydrophobicity of the IL increases its binding affinity and inhibits the fibril formation of lysozyme.
Fibril formation of α-synuclein is linked with Parkinson's disease. The intrinsically disordered nature of α-syn provides extensive conformational plasticity and becomes difficult to characterize its ...transition pathway from native monomeric to disease-associated fibril form. We implemented different simulation methods such as steered dynamics-umbrella sampling, and replica-exchange and conventional MD simulations to access various conformational states of α-syn. Nineteen distinct intermediate structures were identified by free energy landscape and cluster analysis. They were then sorted based on secondary structure and solvent exposure of fibril-core residues to illustrate the fibril dissociation pathway. The analysis showed that following the initial dissociation of the polypeptide chain from the fibril, α-syn might form either compact-conformations by long-range interactions or extended-conformations stabilized by local interactions. This leads α-syn to adapt two different pathways. The secondary structure, solvation, contact distance, interaction energies and backbone dihedrals of thirty-two selected residues were analyzed for all the 19 intermediates. The results suggested that formation of β-turns, reorganization of salt bridges, and dihedral changes in the hydrophobic regions are the major driving forces for helix-fibril transition. Structural features of the intermediates also correlated with the earlier experimental and computational studies. The study provides critical information on the fibrillation pathway of α-syn.
•Steered, replica exchange, and conventional MD simulations of α-syn were performed.•19 metastable conformations were identified by energy landscape or cluster analysis.•Fibril dissociation pathway with 19 intermediate structures was predicted.•α-Syn might follow compact- and extended-conformational pathways.•Analyzed structure & solvation changes and long-range interaction in intermediates.
Protein–surfactant interaction is widely studied to understand stability and structural changes in proteins. In this Article, we have investigated SDS-induced unfolding of RNase A using absorbance, ...intrinsic fluorescence of the protein, anisotropy, TNS fluorescence, and near- and far-UV circular dichroism. Unfolding titration curves obtained from the absorbance and fluorescence changes were fitted into a five-state protein unfolding model by assuming formation of three intermediate states. Free energy changes and m-values of all four transitions between the native and unfolded state were evaluated. The transitions are categorized into two different regions. Region I, up to 0.5 mM of SDS, involves ionic interaction between the protein and SDS where the secondary and tertiary structure of the protein is altered to a less extent. In region II, hydrophobic interaction dominates and has two distinct transitions. The first transition arises from the aggregation of surfactant molecules around the protein hydrophobic sites. In the following transition, the micelles probably expand more, and a few more hydrophobic sites are occupied by the surfactant. In this region, the tertiary contacts are completely broken, and almost 50% of the secondary structure is lost. The aggregation of SDS around the protein starts well below the CMC. These conformational changes can be explained by the necklace and beads model, and the free energy of formation of such a complex for the RNase A–SDS system is found to be 5.2 (±1.0) kcal mol–1. The probable interaction sites and the mechanism of unfolding have been discussed in detail.
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