Leonardo Ribeiro - Academia.edu (original) (raw)

Papers by Leonardo Ribeiro

Anais do Congresso sobre Tecnologias na Educação (Ctrl+e)

Este artigo apresenta um relato dos desafios percebidos na tutoria de um curso on-line de 80 hora... more Este artigo apresenta um relato dos desafios percebidos na tutoria de um curso on-line de 80 horas para “Desenvolvimento de Competências Interdisciplinares com o Raciocínio Computacional para Professores da Educação Básica”. O curso foi promovido em colaboração por duas universidades federais e alcançou mais de 90 pessoas entre estudantes de licenciatura (professores em formação), professores iniciantes na educação básica (com até cinco anos de atuação) e professores experientes, com mais de cinco anos de atuação na Educação Básica. Para além dos desafios relacionados à temática do curso e à perspectiva intergeracional dos participantes, houve desafios intrínsecos ao exercício da tutoria on-line por estudantes de graduação. Foram utilizadas as narrativas dos tutores e dos professores-participantes para relatar os desafios apontados neste artigo, com endereçamento de reflexões acerca da formação de professores on-line para desenvolvimento do Raciocínio Computacional.

Energies

The use of hydrogen as an alternative to fossil fuels for vehicle propulsion is already a reality... more The use of hydrogen as an alternative to fossil fuels for vehicle propulsion is already a reality. However, due to its physical characteristics, storage is still a challenge. There is an innovative way, presented in this study, to store hydrogen in conventional vehicles propelled by spark-ignition reciprocating engines and fuel cells, using hydrogen as fuel; the storage of hydrogen will be at high pressure within small spheres randomly packed in a tank, like the conventional tank of fuel used nowadays in current vehicles. Therefore, the main purpose of the present study is to assess the performance of this storage system and compare it to others already applied by car manufacturers in their cars. In order to evaluate the performance of this storage system, some parameters were taken into account: The energy stored by volume and stored by weight, hydrogen leakage, and compliance with current standards. This system is safer than conventional storage systems since hydrogen is stored in...

Annals of Botany

• Background and Aims Palm seeds are interesting models for studying seed reserve mobilization at... more • Background and Aims Palm seeds are interesting models for studying seed reserve mobilization at the tissue level due to the abundance and complexity of reserves stored in their living endosperm cells and the development of a highly specialized haustorium. We studied structural and physiological aspects of the initial phases of reserve mobilization in seeds of a neotropical palm, Butia capitata, and sought to characterize the interactions between the different developmental pathways of the haustorium and endosperm. • Methods Morphological and histochemical evaluations of the haustorium, the endosperm adjacent to the embryo, and the peripheral endosperm of dry, imbibed, dormant seeds and seeds geminating for 2, 5 and 10 d were performed. Biochemical analyses included determinations of endo-β-mannanase activity, hormonal profiling (20 hormones belonging to eight classes) and H 2 O 2 quantification in various tissues. • Key Results The mobilization of haustorium reserves was associated with germination and involved distinct hormonal alterations in the endosperm related to H 2 O 2 production. The mobilization of endosperm reserves occurred as a post-germination event controlled by the seedling and involved major structural changes in the haustorium, including growth (which increased contact with, and pressure on, the endosperm) and the formation of an aerenchyma (thus facilitating O 2 diffusion). The flow of O 2 to the endosperm and changes in endogenous contents of H 2 O 2 and hormones (cytokinins, auxins, brassinosteroids and ethylene) induced the establishment of an endosperm digestion zone and the translocation of reserves to the haustorium. • Conclusions The haustorium-endosperm relationship during reserve mobilization plays a pivotal role in signal integration between growth and degradation pathways in germinating seeds of Butia capitata.

Computers & Graphics

We propose and evaluate several deep network architectures for measuring the similarity between s... more We propose and evaluate several deep network architectures for measuring the similarity between sketches and photographs, within the context of the sketch based image retrieval (SBIR) task. We study the ability of our networks to generalize across diverse object categories from limited training data, and explore in detail strategies for weight sharing, pre-processing, data augmentation and dimensionality reduction. In addition to a detailed comparative study of network configurations, we contribute by describing a hybrid multi-stage training network that exploits both contrastive and triplet networks to exceed state of the art performance on several SBIR benchmarks by a significant margin. Datasets and models are available at www.cvssp.org.

Brazilian Journal of Biology

Ecological niche modeling has contributed to the investigation of the geographical distribution a... more Ecological niche modeling has contributed to the investigation of the geographical distribution and conservation of rare or little recorded species. Therefore, we studied the known and potential distributions of Colobosauroides carvalhoi Soares and Caramaschi 1998 and discuss the implications for its conservation. Data were obtained by manual collections made in quarterly samplings in three different regions, considering the regions with occurrence records and surrounding areas. The known distribution was determined by occurrence records and literature data, and potential distribution was estimated with an ecological niche model by the MaxEnt algorithm. Twenty-five specimens were collected exclusively in forest formations of Caatinga and Caatinga-Cerrado. Our data corroborated the relative rarity of C. carvalhoi and reflected the biogeographical history of the group, where it is restricted to forest formations with milder environmental conditions. The occurrence records indicated ne...

Protoplasma, Jan 18, 2018

Latex is a complex plant secretion with both ecological and economic importance. There is little ... more Latex is a complex plant secretion with both ecological and economic importance. There is little information currently available on the cytological aspects of the ontogenesis of anastomosed laticifers, the ducts originating through the lysis of adjacent cell walls. Hancornia speciosa is a tree typical of the Cerrado (neotropical savanna) biome. Its latex has medicinal value and is also used to produce rubber. The ontogenesis of its laticifers and the process of latex synthesis are described here. Structural, cytochemical, and ultrastructural analyses of the stem apex and phytochemical analyses of the latex were performed. Laticifer ontogenesis begins early in promeristem cells and subsequently extends through the procambial region. The laticifer precursor cells demonstrate intense metabolic activity, evidenced by starch accumulation and the proliferation of mitochondria, dictyosomes, endoplasmic reticulum, and ribosomes-resulting in the thickening of the cell walls and accumulations...

Boletim do Instituto de Pesca

O objetivo deste estudo foi analisar comparativamente as principais características morfológicas ... more O objetivo deste estudo foi analisar comparativamente as principais características morfológicas e histomorfométricas de ovários e testículos de Astyanax lacustris (Lütken, 1875) e Psellogrammus kennedyi (Eigenmann, 1903). Os peixes foram obtidos entre abril de 2014 e março de 2015, no Reservatório Monte Alegre (Salgueiro, Pernambuco). No total, 240 indivíduos foram observados macroscopicamente e, destes, 126 gônadas foram analisadas histologicamente. Durante o período estudado, A. lacustris apresentou quatro diferentes estádios gonadais e P. kennedyi apresentou três. Para ambas as espécies, em todos os meses foram detectados macroscopicamente, ovócitos vitelogênicos e, microscopicamente, ovócitos pré-vitelogênicos. O diâmetro dos ovócitos vitelogênicos foi maior (471,68 µm±160,55; p<0,05) para fêmeas de A. lacustris. O diâmetro dos túbulos seminíferos (114,68 µm±34,57; p<0,05) e a altura do epitélio germinativo (18,75 µm±5,47; p<0,05) foram maiores para P. kennedyi. Os testículos maduros em A. lacustris apresentaram epitélio germinativo com bordas melhor delimitadas, quando comparado a P. kennedyi. As observações macroscópicas demonstraram que os maiores valores do índice gonadossomático (IGS) de ambas as espécies coincidiu com o período de maior precipitação na região (entre novembro/2014 e maio/2015). Por fim, concluiu-se que as duas espécies apresentam desova parcelada com desenvolvimento ovocitário assincrônico. Palavras-chave: lambari; reprodução de peixes; morfologia gonadal; histologia.

Revista Brasileira de Fruticultura

Soluble solids (SS), titratable acidity (TA), SS/TA ratio, pH, moisture, soluble sugars (SSU), to... more Soluble solids (SS), titratable acidity (TA), SS/TA ratio, pH, moisture, soluble sugars (SSU), total reducing sugars (RSU), and non-reducing sugars (NRS) were assessed in the pulp of pequi fruits collected at three ripening stages: from the plant, from the ground after naturally falling off, and collected from the ground three days after naturally falling off. The evaluation was performed after six months of freezer storage both for fruits subjected to quick freezing (liquid nitrogen followed by freezer) and slow freezing (straight into the freezer). The variables assessed were not influenced by the freezing method. The SS, TA, and RSU contents increased with the ripening stage, suggesting that the fruits collected from the plant are still immature and have lower quality than those collected after naturally falling off. Although considered mature when they fall off, fruits consumed three days after naturally falling off have better quality.

BMC cardiovascular disorders, Jun 13, 2017

Knowledge of the normal limits of the electrocardiogram (ECG) is mandatory for establishing which... more Knowledge of the normal limits of the electrocardiogram (ECG) is mandatory for establishing which patients have abnormal ECGs. No studies have assessed the reference standards for a Latin American population. Our aim was to establish the normal ranges of the ECG for pediatric and adult Brazilian primary care patients. This retrospective observational study assessed all the consecutive 12-lead digital electrocardiograms of primary care patients at least 1 year old in Minas Gerais state, Brazil, recorded between 2010 and 2015. ECGs were excluded if there were technical problems, selected abnormalities were present or patients with selected self-declared comorbidities or on drug therapy. Only the first ECG from patients with multiple ECGs was accepted. The University of Glasgow ECG analysis program was used to automatically interpret the ECGs. For each variable, the 1st, 2nd, 50th, 98th and 99th percentiles were determined and results were compared to selected studies. A total of 1,493...

Check List, 2016

This article provides a new record for Enyalius bibronii from municipality of Tenente Laurentino ... more This article provides a new record for Enyalius bibronii from municipality of Tenente Laurentino Cruz, state of Rio Grande do Norte, northeastern Brazil. The collection site is located in a mountain forest enclave belonging to the Caatinga domain. This record extends the species distribution towards central region of the state.

Revista Ceres, 2011

Este trabalho foi desenvolvido com objetivo de avaliar os efeitos da luz, das concentrações de sa... more Este trabalho foi desenvolvido com objetivo de avaliar os efeitos da luz, das concentrações de sais MS e de sacarose sobre a germinação, in vitro, de embriões, e o desenvolvimento de plântulas de coquinho-azedo (Butia capitata (Mart.) Becc.). Para o preparo do meio de cultivo, foram utilizados sais MS suplementados com vitaminas, mio-inositol, caseína hidrolizada, carvão ativado, sacarose e ágar. Para avaliação do efeito da luminosidade, embriões zigóticos foram cultivados na presença e na ausência de luz. Diferentes concentrações de minerais MS (0; 25; 50; 75 e 100% em relação à formulação original do meio MS) foram testadas em associação com duas concentrações de sacarose ( de0 a 2%). Em ambos os experimentos, avaliaram-se, após 30 dias da inoculação, percentuais de oxidação, germinação e emissão de raízes e bainhas foliares. Os resultados obtidos mostraram que condição de luminosidade não afetou a germinação, porém, a ausência de luz favoreceu a emissão de raízes. Ocorreu o along...

Anais Do Encontro Virtual De Documentacao Em Software Livre E Congresso Internacional De Linguagem E Tecnologia Online, Oct 6, 2013

African Journal of Biotechnology, 2013

Unimontes Cientifica, Jun 25, 2008

Resumo: Foram avaliadas as propriedades alelopáticas dos extratos aquoso (material vegetal + água... more Resumo: Foram avaliadas as propriedades alelopáticas dos extratos aquoso (material vegetal + água fervente) e etanólico (material vegetal + etanol 80%) de Anadenanthera colubrina, Acacia bahiensis, Albizia blanchetii, Chloroleucon tortum, Machaerium scleroxylon e Copaifera langsdorffii sobre a germinação e o desenvolvimento de plântulas de alface. Os extratos aquosos de flores e folhas de C. tortum e de folhas de A. blanchetii inibiram a taxa de germinação em 99 e 100%, respectivamente. Os maiores efeitos inibitórios sobre o comprimento das plântulas foram promovidos pelos extratos foliares aquoso de M. scleroxylon e etanólicos de C. langsdorffii e A. bahiensis, com 100, 85 e 82% de inibição, respectivamente.

Brazilian Journal of Kinanthropometry and Human Performance, 2003

Corporal (IMC) tem sido tradicionalmente utilizado em estudos clínicos e epidemiológicos, como in... more Corporal (IMC) tem sido tradicionalmente utilizado em estudos clínicos e epidemiológicos, como instrumento para identifi car sobrepeso e obesidade. Rabelo & Araújo (2001) sugerem que a utilização do Recíproco do Índice Ponderal (RIP), pelas características de sua formulação, seria mais adequada. O objetivo deste trabalho foi comparar a identifi cação de sobrepeso feita pelos dois índices, tendo como medida critério a estimativa do percentual de gordura (G%).

The present work has two objectives. The first one is to provide a brief description of a system ... more The present work has two objectives. The first one is to provide a brief description of a system developed to improve the medical assistance in small cities that do not have full medical staff and equipments. The system provides an environment where the medical professionals can use the Internet to search databases and access the patient medical information, such as exams and reports. In this context, a medical specialist access a central web server and is able to make expert diagnosis reports based on exams stored in distributed medical databases. The second objective is to develop an information retrieval system over different databases to optimize the search process of medical information. Semantic Indexing and similarity evaluation using medical dictionaries are among the methods proposed in this work. Our goal is to improve efficiency and effectiveness of the information retrieval system.