138 research outputs found
Optimized hybrid ensemble learning approaches applied to very short-term load forecasting
The significance of accurate short-term load forecasting (STLF) for modern power systems’ efficient and secure operation is paramount. This task is intricate due to cyclicity, non-stationarity, seasonality, and nonlinear power consumption time series data characteristics. The rise of data accessibility in the power industry has paved the way for machine learning (ML) models, which show the potential to enhance STLF accuracy. This paper presents a novel hybrid ML model combining Gradient Boosting Regressor (GBR), Extreme Gradient Boosting (XGBoost), k-Nearest Neighbors (kNN), and Support Vector Regression (SVR), examining both standalone and integrated, coupled with signal decomposition techniques like STL, EMD, EEMD, CEEMDAN, and EWT. Through Automated Machine Learning (AutoML), these models are integrated and their hyperparameters optimized, predicting each load signal component using data from two sources: The National Operator of Electric System (ONS) and the Independent System Operators New England (ISO-NE), boosting prediction capacity. For the 2019 ONS dataset, combining EWT and XGBoost yielded the best results for very short-term load forecasting (VSTLF) with an RMSE of 1,931.8 MW, MAE of 1,564.9 MW, and MAPE of 2.54%. These findings highlight the necessity for diverse approaches to each VSTLF problem, emphasizing the adaptability and strength of ML models combined with signal decomposition techniques
Higgs Boson Production in Association with Three Jets
The scattering amplitudes for Higgs + 5 partons are computed, with the Higgs
boson produced via gluon fusion in the large top-quark mass limit. A
parton-level analysis of Higgs + 3 jet production via gluon fusion and via
weak-boson fusion is presented, and the effectiveness of a central-jet veto is
analysed.Comment: 26 pages, 4 Postscript figures, uses JHEP3.cl
Auditory stimulation and cardiac autonomic regulation
Previous studies have already demonstrated that auditory stimulation with music influences the cardiovascular system. In this study, we described the relationship between musical auditory stimulation and heart rate variability. Searches were performed with the Medline, SciELO, Lilacs and Cochrane databases using the following keywords: "auditory stimulation", "autonomic nervous system", "music" and "heart rate variability". The selected studies indicated that there is a strong correlation between noise intensity and vagal-sympathetic balance. Additionally, it was reported that music therapy improved heart rate variability in anthracycline-treated breast cancer patients. It was hypothesized that dopamine release in the striatal system induced by pleasurable songs is involved in cardiac autonomic regulation. Musical auditory stimulation influences heart rate variability through a neural mechanism that is not well understood. Further studies are necessary to develop new therapies to treat cardiovascular disorders
Two-loop Yang-Mills diagrams from superstring amplitudes
Starting from the superstring amplitude describing interactions among
D-branes with a constant world-volume field strength, we present a detailed
analysis of how the open string degeneration limits reproduce the corresponding
field theory Feynman diagrams. A key ingredient in the string construction is
represented by the twisted (Prym) super differentials, as their periods encode
the information about the background field. We provide an efficient method to
calculate perturbatively the determinant of the twisted period matrix in terms
of sets of super-moduli appropriate to the degeneration limits. Using this
result we show that there is a precise one-to-one correspondence between the
degeneration of different factors in the superstring amplitudes and
one-particle irreducible Feynman diagrams capturing the gauge theory effective
action at the two-loop level.Comment: 42 pages plus appendices, 10 figure
RESVERATROL INCLUSION COMPLEX WITH β-CYCLODEXTRIN (RCD): CHARACTERIZATION AND EVALUATION OF TOXICITY IN WISTAR RATS
Objective: The aim of this study was to characterise the resveratrol inclusion complex with β-cyclodextrin (RCD) and evaluate their toxicity in wistar rats.Methods: The RCD were prepared in ultra-turrax. For characterization of the RCD were used: Fourier transform infra-red Spectroscopy, Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC) and X-ray powder diffraction. The RCD and others 4 treatments were performed by the chronic oral administration in 35 rats during 60 ds. After the treatments they were euthanized and the serum blood were collected to analyzed some hemogram and biochemical parameters including aspartyl aminotransferase (AST); alanine aminotransferase (AST); phosphatase alkaline (ALP); total bilirubin (TB); direct bilirubin (DB); total protein (TP); total cholesterol (TC), triacylglycerol (TAG), very low-density lipoprotein (VLDL), high-density lipoprotein (HDL), calcium, iron and phosphate using fully automated biochemistry analyzer.Results: The characterization results indicated a successful formation of the RCD. All hematological parameters analysed were within the normal values in all the groups. Furthermore, the hemogram and biochemical parameters were significantly (P>0.05) similar to the control group.Conclusion: The daily oral administration during 60 d of RCD are not harmful on blood parameters of Wistar rats. Thus, RCD can be used safely for treatment of some metabolic diseases
Valor nutritivo de pastagens de capim-elefante manejadas sob sistema convencional e agroecológico.
O capim-elefante é utilizado, na sua grande maioria, em sistemas convencionais de produção animal. O objetivo deste trabalho foi comparar o valor nutritivo do capimelefante em sistemas de manejo agroecológico e convencional, quanto a proteína bruta (PB), fibra em detergente neutro (FDN) e digestibilidade in vitro da matéria seca (DIVMS). Foram usados quatro piquetes, com 0,12ha cada um. No sistema convencional, o capim-elefante foi estabelecido singularmente. No sistema agroecológico, o plantio foi feito em linhas afastadas de 3m. Nas entrelinhas, estabeleceu-se a aveia e o azevém no período hibernal, enquanto que no período estival permitiu-se o desenvolvimento de espécies espontâneas. A adubação foi feita com fertilizantes orgânicos (150kg ha-1 de N). No sistema agroecológico, foram conduzidos sete pastejos, de 24/04/2004 a 05/05/2005. Na pastagem convencional, usouse a mesma quantidade de N (uréia), sendo conduzidos quatro ciclos de pastejo, de 06/10/2004 a 05/05/2005. Para ambos os sistemas foram utilizadas vacas da raça Holandês, recebendo complementação alimentar de 3,5kg dia-1 de concentrado com 20% de proteína bruta, constituindo-se nos animais experimentais. Nas avaliações, considerou-se a massa de forragem inicial com base na matéria seca (MS), os componentes botânicos da pastagem e estruturais do capimelefante. As análises de qualidade foram feitas em amostras de pastejo simulado. O delineamento experimental foi o inteiramente casualizado com dois tratamentos, convencional e agroecológico, duas repetições (piquetes) e em parcelas incompletas subdivididas no tempo (pastejos). Houve interação (P<0,05) entre tratamentos e pastejos em todas as variáveis. Na pastagem agroecológica, o modelo que melhor se ajustou foi o cúbico para todas as variáveis, em função do tempo de pastejo. Na pastagem convencional, a PB e a DIVMS ajustaram-se melhor ao modelo linear, com taxa positiva de crescimento, sendo observado comportamento inverso para FDN, com o decorrer dos pastejos. Tanto na pastagem convencional quanto na agroecológica encontraram-se associações negativas entre lâmina foliar do capim-elefante com PB e DIVMS e positiva com FDN. Ambos os sistemas apresentaram teores qualitativos elevados das pastagens, considerando-se a adubação, o manejo e o tempo de utilização
Guanosine effect on cholesterol efflux and apolipoprotein E expression in astrocytes
The main source of cholesterol in the central nervous system (CNS) is represented by glial cells, mainly astrocytes, which also synthesise and secrete apolipoproteins, in particular apolipoprotein E (ApoE), the major apolipoprotein in the brain, thus generating cholesterol-rich high density lipoproteins (HDLs). This cholesterol trafficking, even though still poorly known, is considered to play a key role in different aspects of neuronal plasticity and in the stabilisation of synaptic transmission. Moreover, cell cholesterol depletion has recently been linked to a reduction in amyloid beta formation. Here we demonstrate that guanosine, which we previously reported to exert several neuroprotective effects, was able to increase cholesterol efflux from astrocytes and C6 rat glioma cells in the absence of exogenously added acceptors. In this effect the phosphoinositide 3 kinase/extracellular signal-regulated kinase 1/2 (PI3K/ERK1/2) pathway seems to play a pivotal role. Guanosine was also able to increase the expression of ApoE in astrocytes, whereas it did not modify the levels of ATP-binding cassette protein A1 (ABCA1), considered the main cholesterol transporter in the CNS. Given the emerging role of cholesterol balance in neuronal repair, these effects provide evidence for a role of guanosine as a potential pharmacological tool in the modulation of cholesterol homeostasis in the brain
Use of twitter data for waste minimisation in beef supply chain
Approximately one third of the food produced is discarded or lost, which accounts for 1.3 billion tons per annum. The waste is being generated throughout the supply chain viz. farmers, wholesalers/processors, logistics, retailers and consumers. The majority of waste occurs at the interface of retailers and consumers. Many global retailers are making efforts to extract intelligence from customer’s complaints left at retail store to backtrack their supply chain to mitigate the waste. However, majority of the customers don’t leave the complaints in the store because of various reasons like inconvenience, lack of time, distance, ignorance etc. In current digital world, consumers are active on social media and express their sentiments, thoughts, and opinions about a particular product freely. For example, on an average, 45,000 tweets are tweeted daily related to beef products to express their likes and dislikes. These tweets are large in volume, scattered and unstructured in nature. In this study, twitter data is utilised to develop waste minimization strategies by backtracking the supply chain. The execution process of proposed framework is demonstrated for beef supply chain. The proposed model is generic enough and can be applied to other domains as well
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