127 research outputs found

    Evolutionary-enhanced quantum supervised learning model

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    Quantum supervised learning, utilizing variational circuits, stands out as a promising technology for NISQ devices due to its efficiency in hardware resource utilization during the creation of quantum feature maps and the implementation of hardware-efficient ansatz with trainable parameters. Despite these advantages, the training of quantum models encounters challenges, notably the barren plateau phenomenon, leading to stagnation in learning during optimization iterations. This study proposes an innovative approach: an evolutionary-enhanced ansatz-free supervised learning model. In contrast to parametrized circuits, our model employs circuits with variable topology that evolves through an elitist method, mitigating the barren plateau issue. Additionally, we introduce a novel concept, the superposition of multi-hot encodings, facilitating the treatment of multi-classification problems. Our framework successfully avoids barren plateaus, resulting in enhanced model accuracy. Comparative analysis with variational quantum classifiers from the technology's state-of-the-art reveal a substantial improvement in training efficiency and precision. Furthermore, we conduct tests on a challenging dataset class, traditionally problematic for conventional kernel machines, demonstrating a potential alternative path for achieving quantum advantage in supervised learning for NISQ era

    Neurophysiological Repercussions of Anabolic Steroid Abuse: A Road into Neurodegenerative Disorders

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    Since its discovery, several chemical modifications in the testosterone molecule have been done by pharmaceutical industry in order to improve its pharmacological effects, resulting in the creation of anabolic steroids (AS). Despite the therapeutic benefits, AS abuse has spread among elite and recreational athletes in the search for improvements on physical appearance and physical performance. Illicit use of anabolic AS has been correlated with several adverse effects, such as cardiovascular, endocrine, reproductive, and neurobehavioral dysfunctions. Recently, declines on cognitive and mnemonic performance have been demonstrated clinically and experimentally. Experimental studies have demonstrated that these neurological dysfunctions are correlated to spread neuronal apoptosis throughout important areas of the central nervous system (CNS), such as hippocampus and cortex. Several pathophysiological mechanisms have been linked to the AS-induced neurotoxicity, including redox imbalance and recruitment of pro-apoptotic downstream pathways. Furthermore, exposure to AS has arisen as a potential risk factor to the development of Alzheimer’s disease. Altogether, these evidences imply that AS abuse per se induces neurodegeneration and can aggravate the prognosis of neurodegenerative diseases

    Production and Partial Characterization of Cellulases from Trichoderma sp. IS-05 Isolated from Sandy Coastal Plains of Northeast Brazil

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    This study evaluated the production of cellulolytic enzymes by Trichoderma sp. IS-05 strain, isolated from sand dunes, according to its ability to grow on cellulose as carbon source. Wheat bran was tested as the carbon source and peptone tested as the nitrogen source. Different concentrations of carbon and nitrogen were tested using a factorial design to identify optimal cellulase activity production. The results showed that media containing wheat bran 4.0% (w/v) and peptone 0.25% (w/v) lead to the highest production, 564.0 U L−1 of cellulase, obtained after 2 days of fermentation. The pH and temperature profile showed optimal activity at pH 3.0 and 60°C. As for thermostability, the cellulase was most tolerant at 60°C, retaining more than 59.6% of maximal activity even after 4 hours of incubation. The combination of acid pH, high temperature tolerance, and production of cellulase from agro-industrial residues by Trichoderma sp. IS-05 offers possibilities condition for the biomass hydrolysis process to produce bioethanol

    A thermotolerant xylan-degrading enzyme is produced by Streptomyces malaysiensis AMT-3 using by-products from the food industry

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    ABSTRACT: This study evaluated the production of endoxylanases by Streptomyces malaysiensis AMT-3 in submerged fermentation using by-products of the food industry at 28ºC. In shake-flasks experiments, the highest endoxylanase activity of 45.8 U.mL-1 was observed within 6 days in a medium containing (w/v) 2.5% wheat bran and 1.2% corn steep liquor. The same culture conditions were used to evaluate the enzyme production in a 2 L stirred tank reactor under different agitation (300, 450 and 600 rev.min-1) and aeration (30 and 60 L.h-1) conditions. The use of 450 rev.min-1 coupled to an aeration of 90 L.h-1 resulted on 81.3 U.mL-1 endoxylanase activity within 5 days. The effect of temperature and pH on endoxylanase activity and stability showed the highest activity at 60 ºC and pH 6.0. Zymography showed the presence of three xylanolytic bands with molecular masses of 690, 180 and 142 kDa. The results showed that the thermotolerant actinobacterial endoxylanase can be produced in high titers using by-product of the food industry.info:eu-repo/semantics/publishedVersio

    Production of thermophilic and acidophilic endoglucanases by mutant Trichoderma atroviride 102C1 using agro-industrial by-products

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    Many traditional mutagenic strategies have been used to improve cellulase production by microorganisms, especially fungi species. Trichoderma species are among cellulolytic fungi, those that have been most extensively studied, due to their efficient production of these enzymes. In the present study, N-methyl-N´-nitro-N nitrosoguanidine (NTG) was used as mutagenic agent to obtain cellulolytic mutant from wild strain T. atroviride 676. After mutagenic procedures, two strains (102C1 and 104C2) were selected as promising cellulase-producing mutant. The effect of the carbon (sugarcane bagasse: SCB) and nitrogen (corn steep liquor: CSL) sources on endoglucanase production by the mutants 102C1 and 104C2 was studied using submerged cultivations at 28°C. Different concentrations of SCB and CSL were used and nine different media were generated. Mutant 102C1 showed the best results when using 2.5% SCB and 0.7% CSL. A central composite rotational design (CCRD) was performed to estimate optimal conditions of pH and temperature for endoglucanase activity of strain 102C1, which were pH 3.6 and temperature 66°C. The characterization of this acidophilic and thermophilic endoglucanase activity produced by the mutant strain 102C1 allows its use in biotechnological applications, particularly in the hydrolysis of agro industrial residues, such as SCB, for bioethanol production.Keywords: Trichoderma atroviride, CMCase, nitrosoguanidine, sugarcane bagasse, corn steep liquo

    Chemical and antimicrobial analysis of husk fiber aqueous extract from Cocos nucifera L.

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    Cocos nucifera L. (Arecaceae) is a widely distributed species around the tropical areas. Popular uses have been reported in the treatment of arthritis and diarrhea. This study evaluates the antimicrobial activity of husk fiber aqueous extract from C. nucifera and performed the identification of some biological active substances. The minimal inhibitory concentration (MIC) against human pathogen microorganisms was determined. Chromatographic and spectrometric procedures were also performed to isolate and identify the components present in the extract. In the MIC assay of crude aqueous extract, only the methicillin sensible and the resistant (MRSA) Staphylococcus aureus strains were susceptible at 156 μg/mL. The ethyl acetate partition taken from crude extract was more promising (MIC of 78 μg/mL). No fungal growth inhibition was observed. Catechin, epicatechin, two procyanidin dimers and condensed tannins were found in the organic phase. In addition, gallic and ellagic acids were detected for the first time in C. nucifera husk fiber. Gallic acid showed MIC of 39 μg/mL and minimal bactericidal concentration (MBC) at 78 μg/mL. Ellagic acid was not active against the tested strains, as well as catechin and epicatechin. Additionally catechin, epicatechin, two procyanidin dimers and condensed tannins were also detected. The antimicrobial activity observed was selective to S. aureus strains.Keywords: Antimicrobial analyses, Cocos nucifera, arecaceae, ellagic acid, gallic acid, procyanidins, Staphylococcus aureus strainsAfrican Journal of Biotechnology Vol. 12(18), pp. 2478-248

    Convergência ao padrão IFRS e suavização de resultados em empresas de energia elétrica

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    The objective of this research is to analyze if there has been an increase in earnings management level (GR) using the income smoothing method in the electricity sector companies listed on the B3 with the adoption of the accounting standards of the IASB. The proposal is timely, since, due to the greater flexibility of the rules, there is the possibility of a greater GR. On the other hand, it is a heavily regulated industry, prompting, in turn, the possibility of this factor inhibiting such practices. Were analyzed the financial statements from 2003 to 2007 as the preconvergence period, and 2010 to 2014 as the post-convergence period. As GR proxy, the variance of waste equation proposed by Chen et al. (2010) and Barth et al. (2008) was considered, with adaptations, where a smaller variability in net profit is seen as practice for greater smoothing results and higher GR. The research findings show a reduction in the level of income smoothing after the adoption of IFRS (International Financial Reporting Standards). In fact, the findings indicate that the adoption of international standards for companies in that sector can improve the quality of accounting information and therefore reduce the earnings management levels, mainly due to the demand for greater disclosure and quality of financial reporting, corroborating with the results of the researches of Barth et al. (2008), Iatridis (2010) and Chen et al. (2010). Keywords: income smothing, electricity sector, international standards.O objetivo da pesquisa é o de analisar se houve um aumento no nível de gerenciamento de resultados (GR) pelo método income smoothing nas companhias do subsetor de energia elétrica listadas na B3 com a adoção das normas contábeis do IASB. A referida proposta é oportuna, uma vez que, em razão da maior flexibilidade das normas, há possibilidade de maior GR. Por outro lado, trata-se de subsetor fortemente regulamentado, instigando, por seu turno, se esse fator poderia inibir tais práticas. Foram analisadas as demonstrações financeiras de 2003 a 2007 como pré-convergência e de 2010 a 2014 como pós-convergência. Como proxy de GR, foi considerada a variância dos resíduos da equação proposta por Chen et al. (2010) e Barth et al. (2008), com adaptações, em que uma menor variabilidade no lucro líquido é vista como prática de maior suavização de resultados e maior GR. Os achados da pesquisa evidenciam uma redução no nível de income smoothing a partir da adoção das IFRS (International Financial Reporting Standards). Com efeito, as conclusões permitem inferir que a adoção dessas normas nas empresas do referido subsetor pode melhorar a qualidade da informação contábil e, por conseguinte, reduzir os níveis de gerenciamento de resultados, principalmente pela exigência de maior evidenciação e qualidade dos relatórios contábeis, o que corrobora os resultados das pesquisas de Barth et al. (2008), Iatridis (2010) e Chen et al. (2010).Palavras-chave: suavização de resultados, setor elétrico, normas internacionais

    ANÁLISE DAS UNIDADES DE CONSERVAÇÃO NO MUNICÍPIO DE APARECIDA DE GOIÂNIA: RELATO DE UMA EXPERIÊNCIA DE EXTENSÃO UNIVERSITÁRIA: Analysis of conservation units in the municipality of aparecida of goiânia: report of an experience of university extension

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    Esse artigo tem como objetivo revelar uma experiência de extensão universi- tária que teve como foco analisar a importância da vegetação em áreas urbanas e urbanizadas. Para alcançar o objetivo aplicou-se a metodologia Hands-on a partir das atividades de extensão do projeto Aprender Fazendo para estudantes do ensino médio de escolas públicas e estudantes do ensino superior da Universidade Federal de Goiás, Aparecida de Goiânia. Os principais resultados revelaram práticas multi- disciplinares de ensino através de atividades em campo. Desse modo, na perspectiva das geociências, realizou-se análises integradas da paisagem nas Unidades de Con- servação e da relação entre a geologia local, preservação dos solos com a presença de vegetação nativa e das nascentes. Na perspectiva da cartografia, os estudantes do ensino superior elaboraram mapeamentos temáticos que foram analisados por estu- dantes do ensino médio
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