68 research outputs found
Deformation forecasting of a hydropower dam by hybridizing a long short-term memory deep learning network with the coronavirus optimization algorithm
The safety operation and management of hydropower dam play a critical role
in social-economic development and ensure people’s safety in many countries;
therefore, modeling and forecasting the hydropower dam’s deformations with
high accuracy is crucial. This research aims to propose and validate a new model
based on deep learning long short-term memory (LSTM) and the coronavirus
optimization algorithm (CVOA), named CVOA-LSTM, for forecasting the defor mations of the hydropower dam. The second-largest hydropower dam of Viet nam, located in the Hoa Binh province, is focused. Herein, we used the LSTM
to establish the deformation model, whereas the CVOA was utilized to opti mize the three parameters of the LSTM, the number of hidden layers, the learn ing rate, and the dropout. The efficacy of the proposed CVOA-LSTM model is
assessed by comparing its forecasting performance with state-of-the-art bench marks, sequential minimal optimization for support vector regression, Gaussian
process, M5’ model tree, multilayer perceptron neural network, reduced error
pruning tree, random tree, random forest, and radial basis function neural net work. The result shows that the proposed CVOA-LSTM model has high fore casting capability (R2 = 0.874, root mean square error = 0.34, mean absolute
error = 0.23) and outperforms the benchmarks. We conclude that CVOA-LSTM
is a new tool that can be considered to forecast the hydropower dam’s deforma tions.Ministerio de Ciencia, Innovación y Universidades PID2020-117954RB-C2
Urinary Excretion of Mimosine Derivatives by Cows with and without Experience in Consumption of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e
Leucaena leucocephala is a leguminous tree widely distributed in the tropical regions of the world. In Mexico, it has been incorporated into silvopastoral systems and is highly regarded, owing to its high content of crude protein. Nonetheless, L. leucocephala contains secondary metab-olites, such as mimosine, a non-protein free amino acid, which may induce toxic effects in unadapted ruminants that consume the forage (Hammond 1995). Although Synergistes jonesii, an anaerobic bacterium, has the ability to degrade 3,4-DHP and 2,3-DHP to non-toxic compounds (Allison et al. 1992), in Mexico its presence has not yet been confirmed. Recent work has suggested the occurrence of sub-clinical toxicity to 3,4-DHP and 2,3-DHP in cattle grazing L. leucocephala in Australia and Thailand (Graham 2007; Dalzell et al. 2012; Phaikaew et al. 2012). Several options such as the transfer of rumen liquor and the adaptation of ruminants to the intake of L. leucocephala have been studied in an attempt to reduce the excretion of mimosine and its metabolites (Palmer et al. 2010).
The aim of the present work was to evaluate the effect of the experience of consumption of L. leucocephala on excretion of mimosine derivatives (3,4-DHP and 2,3-DHP) in the urine of cattle
Coronavirus Optimization Algorithm: A Bioinspired Metaheuristic Based on the COVID-19 Propagation Model
This study proposes a novel bioinspired metaheuristic simulating how the coronavirus spreads and infects healthy people. From a primary infected individual (patient zero), the coronavirus rapidly infects new victims, creating large populations of infected people who will either die or spread infection. Relevant terms such as reinfection probability, super-spreading rate, social distancing measures, or traveling rate are introduced into the model to simulate the coronavirus activity as accurately as possible. The infected population initially grows exponentially over time, but taking into consideration social isolation measures, the mortality rate, and number of recoveries, the infected population gradually decreases. The coronavirus optimization algorithm has two major advantages when compared with other similar strategies. First, the input parameters are already set according to the disease statistics, preventing researchers from initializing them with arbitrary values. Second, the approach has the ability to end after several iterations, without setting this value either. Furthermore, a parallel multivirus version is proposed, where several coronavirus strains evolve over time and explore wider search space areas in less iterations. Finally, the metaheuristic has been combined with deep learning models, to find optimal hyperparameters during the training phase. As application case, the problem of electricity load time series forecasting has been addressed, showing quite remarkable performance.Ministerio de Economía y Competitividad TIN2017-88209-C
Productive Performance of Growing Cattle Grazing a Silvopastoral System with \u3cem\u3eLeucaena leucocephala\u3c/em\u3e
In tropical regions, the feeding of cattle is usually based on the grazing of medium to low quality grasses. Low fertility of soils, changing climatic conditions and the poor management of pastures, have further reduced the quality and forage yield of pastures. The low availability and quality of grasses gives modest weight gains for grazing cattle and this in-turn causes low economical efficiency of cattle production systems (Campos et al. 2011). Silvopastoral systems represent a sustainable option for meat and milk production in the tropics. The association of grasses with legumes such as Leucaena leucocephala (leucaena) supply forage with high concentration of crude protein (Barros et al. 2012). There are reports in the scientific literature which show that intake of leucaena can result in good rates of growth in cattle (e.g. Shelton and Dalzell 2007); however the presence of the free amino acid mimosine and its metabolites (3,4-DHP and 2,3-DHP) in leucaena when the anaerobic bacteria Synergistes jonesii (Allison et al. 1992) is absent from the rumen, may induce subclinical toxicity in grazing ruminants (Graham 2007; Dalzell et al. 2012; Phaikaew et al. 2012). There are no reports in Mexico regarding the rate of growth of cattle grazing silvopastoral systems with leucaena.
The aim of the present work was to evaluate the rate of growth of cattle grazing an association of Panicum maximum and leucaena compared to that of cattle fed a high grain ration (feedlot)
Urinary Excretion of Mimosine Metabolites by Hair Sheep Fed Foliage of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e
Leucaena leucocephala is an adapted legume widely distributed in the tropical regions of Mexico. The high crude protein content of leucaena leaves renders it appropriate for ruminant feeding under commercial conditions. However, the foliage contains the non-protein amino acid mimosine, which, if consumed in high amounts, may induce toxicity in animals which have not previously consumed the legume or without microorganisms capable of degrading mimosine and its derivatives 2,3-DHP (dihydroxypyridine) and 3,4-DHP (Hammond 1995, Palmer et al. 2010, Dalzell et al. 2012). Barros-Rodríguez et al. (2012) found that dry matter intake and weight gain were reduced when sheep grazed paddocks with 55,000 plants of leucaena per hectare. Early work in Australia led to the isolation of Synergistes jonesii, an anaerobic bacterium able to degrade 3,4-DHP and 2,3-DHP to non-toxic compounds (Allison et al. 1992). In Mexico, the presence of this microorganism in the rumen has not yet been confirmed. Inoculation of non-accustomed animals with rumen liquor of ruminants adapted to the consumption of leucaena can reduce the impact of mimosine and its metabolites on animal health (Ghosh et al. 2009; Palmer et al. 2010). The aim of the present work was to evaluate the effects of transferring rumen liquor of cows adapted to the consumption of L. leucocephala to sheep without experience of consumption, on urinary excretion of 3.4-DHP and 2.3-DHP by means of a colorimetric technique
Prognostic value of discharge heart rate in acute heart failure patients: more relevant in atrial fibrillation?
[Abstract]
Aims.
The prognostic impact of heart rate (HR) in acute heart failure (AHF) patients is not well known especially in atrial fibrillation (AF) patients. The aim of the study was to evaluate the impact of admission HR, discharge HR, HR difference (admission-discharge) in AHF patients with sinus rhythm (SR) or AF on long- term outcomes.
Methods.
We included 1398 patients consecutively admitted with AHF between October 2013 and December 2014 from a national multicentre, prospective registry. Logistic regression models were used to estimate the association between admission HR, discharge HR and HR difference and one- year all-cause mortality and HF readmission.
Results.
The mean age of the study population was 72 ± 12 years. Of these, 594 (42.4%) were female, 655 (77.8%) were hypertensive and 655 (46.8%) had diabetes. Among all included patients, 745 (53.2%) had sinus rhythm and 653 (46.7%) had atrial fibrillation. Only discharge HR was associated with one year all-cause mortality (Relative risk (RR) = 1.182, confidence interval (CI) 95% 1.024–1.366, p = 0.022) in SR. In AF patients discharge HR was associated with one year all cause mortality (RR = 1.276, CI 95% 1.115–1.459, p ≤ 0.001). We did not observe a prognostic effect of admission HR or HRD on long-term outcomes in both groups. This relationship is not dependent on left ventricular ejection fraction.
Conclusions.
In AHF patients lower discharge HR, neither the admission nor the difference, is associated with better long-term outcomes especially in AF patients
Electrophysiological characteristics of permanent atrial fibrillation: insights from research models of cardiac remodeling
[EN] Atrial fibrillation (AF) results in a remodeling of the electrical and structural characteristics of the cardiac tissue which dramatically reduces the efficacy of pharmacological and catheter-based ablation therapies. Recent experimental and clinical results have demonstrated that the complexity of the fibrillatory process significantly differs in paroxysmal versus persistent AF; however, the lack of appropriate research models of remodeled atrial tissue precludes the elucidation of the underlying AF mechanisms and the identification of appropriated therapeutic targets. Here, we summarize the different research models used to date, highlighting the lessons learned from them and pointing to the new doors that should be open for the development of innovative treatments for AF.The authors were supported by grants from the Spanish Ministry of Science and Innovation (PLE2009-0152), the Instituto de Salud Carlos III (Ministry of Economy and Competitiveness, Spain: PI13-01882 and PI13-00903) the Red de Investigacion Cardiovacular (RIC) from Instituto de Salud Carlos III (Ministry of Economy and Competitiveness, Spain). F Atienza served on the advisory board of Medtronic and has received research funding from St. Jude Medical Spain. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.Climent, A.; Guillem Sánchez, MS.; Atienza Fernández, F.; Fernandez-Aviles, F. (2014). Electrophysiological characteristics of permanent atrial fibrillation: insights from research models of cardiac remodeling. Expert Review of Cardiovascular Therapy. 13(1):1-3. https://doi.org/10.1586/14779072.2015.986465S1313
Could a Factor That Does Not Affect Egg Recognition Influence the Decision of Rejection?
Rejection of the parasitic egg is the most important defence of hosts against brood parasites. However, this response is variable among and within species, and egg discrimination is not always followed by egg rejection. Low risk of parasitism and high risk of rejection costs may lead to the acceptance of the parasitic egg even if it has been previously recognized. The main aim of this paper is to answer a relevant question: can a single egg trait provoke the acceptance of an experimental egg previously recognized as foreign? Increased egg mass should hamper the ejection of an egg that has been discriminated because ejection of a heavy egg may imply higher rejection costs for hosts. We have tested this prediction by experimentally parasitizing natural nests of Common Blackbirds (Turdus merula) with non-mimetic model eggs of different mass (heavy, normal-weight, and light) while controlling for potential confounding factors such as egg size and colour. Our results showed that blackbirds more frequently accepted heavy eggs, even when previously recognized. This differential acceptance may be related to insufficient motivation to assume the higher costs that the ejection of a heavy egg could impose.Financial support has been provided by the Consejería Economía, Innovación, Ciencia y Empleo, Junta de Andalucia (research project CVI-6653)
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