Search | SciELO

Need help?

Add field +

Search history

No documents were found for your search

Results: 31

au:ALVARENGA, R. C.

Filters

Collection + Options

All
Brazil

27
Public Health

2
Spain

1
Mexico

1

Journal + Options

All
Brazilian Journal of Biology

3
Pesquisa Veterinária Brasileira

3
Revista Brasileira de Ciência do Solo

3
Revista IBRACON de Estruturas e Materiais

3
Engenharia Agrícola

2
Horticultura Brasileira

2
Journal of the Brazilian Chemical Society

2
Revista de Saúde Pública

2
Actas Urológicas Españolas

1
Anais da Academia Brasileira de Ciências

1
Biota Neotropica

1
Jornal Brasileiro de Patologia e Medicina Laboratorial

1
Journal of Epilepsy and Clinical Neurophysiology

1
Neotropical Ichthyology

1
Revista Brasileira de Engenharia Agrícola e Ambiental

1

Show all...

Language

All
Portuguese

16

Publication Year + Options

All
2017

3
2020

3
1997

2
2001

2
2011

2
2014

2
2021

2
2022

2
2023

2
2000

1
2003

1
2004

1
2005

1
2006

1
2007

1

Show all...

SciELO Thematic Areas + Options

All
Agricultural Sciences

11
Health Sciences

7
Biological Sciences

6
Engineering

3
Exact and Earth Sciences

2
Applied Social Sciences

1
Human Sciences

1
Multidisciplinary

1

WoS Subject Categories + Options

All
Engineering

6
Sciences

5
Agricultural

3
Biology

3
Civil

3
Health

3
Multidisciplinary

3
Science

3
Soil

3
Veterinary

3
Chemistry

2
Environmental

2
Horticulture

2
Policy

2
Research

2

Show all...

WoS Citation Index + Options

All
Science Citation Index Expanded

18
Social Sciences Citation Index

4

Citables and non citables

All
Citable

31

Type of Literature + Options

All
Article

29
Case report

1
Review article

1

Order by

Page of 3 Next

Select this page

Print | Send to email | Export |

Facebook
Twitter
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

0 Selected itens

List all
Erase all

Normalized difference vegetation index for desiccation evaluation with glyphosate + 2,4-D in magnetized spray solution
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Alvarenga, C. B.

; Mundim, G. S. M.

; Santos, E. A.

; Gallis, R. B. A.

; Zampiroli, R.

; Rinaldi, P. C. N.

; Prado, J. R.

Brazilian Journal of Biology

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2023, Volume 83 elocation e246579

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo A magnetização da água e o geoprocessamento são ferramentas cada vez mais utilizadas no manejo de ervas daninhas. Nosso objetivo foi estudar a influência da magnetização da água na eficiência do herbicida e verificar se existe uma relação entre os escores de controle e o índice de vegetação por diferença normalizada (NDVI). No experimento de laboratório, a água foi submetida à magnetização e avaliada em relação a quatro características. No experimento de campo, parcelas de capim-braquiária foram submetidas a tratamentos em esquema fatorial (6 × 2 + 1). Seis fatores herbicidas (doses de glyphosate e glyphosate + 2,4-D) e a magnetização ou ausência de magnetização da calda foram avaliados e comparados com o tratamento controle (sem pulverização). Avaliações de controle de plantas daninhas foram realizadas seis vezes. As imagens foram obtidas usando uma câmera multiespectral incorporada para determinar os valores de NDVI. Os dados relacionados às características da água foram analisados por meio do teste t. O controle de plantas daninhas e os dados de NDVI foram submetidos à análise de variância e são apresentados em gráficos de regressão. A análise de dispersão dos dados NDVI foi realizada de acordo com os escores de controle. O processo de magnetização diminuiu o pH da água e aumentou a tensão superficial, mas não influenciou nos escores de controle ou no NDVI. Conforme a dose de glyphosate foi aumentada, os escores de controle foram maiores e os valores de NDVI foram menores. A água magnetizada não afetou a eficiência biológica dos herbicidas, e houve uma forte correlação entre os escores de controle e os valores de NDVI.

Abstract Water magnetization and geoprocessing are increasingly utilized tools in weed management. Our objective was to study the influence of water magnetization on herbicide efficiency and to verify whether there is a relationship between control scores and the normalized difference vegetation index (NDVI). In the laboratory experiment, water was subjected to magnetization and evaluated with respect to four characteristics. In the field experiment, plots of Brachiaria grass were subjected to treatments in a factorial scheme (6 × 2 + 1). Six herbicidal factors (doses of glyphosate and glyphosate + 2,4-D) and the magnetization or absence of magnetization of the spray solution were evaluated and compared against the control treatment (without spraying). Weed control assessments were carried out six times. Images were obtained using an embedded multispectral camera to determine the NDVI values. Data related to water characteristics were analyzed using the t test. Weed control and NDVI data were subjected to analysis of variance and are presented in regression graphs. Dispersion analysis of NDVI data was performed according to the control scores. The magnetization process decreased the pH of the water and increased the surface tension, but it did not influence the control scores or the NDVI. As the glyphosate dose was increased, the control scores were higher and the NDVI values were lower. Magnetized water did not affect the biological efficiency of the herbicides, and there was a strong correlation between the control scores and the NDVI values.

https://doi.org/10.1590/1519-6984.246579 540 downloads

Herpetofauna of protected areas in the Caatinga VIII: An updated checklist for the Serra das Confusões region with new data from Serra Vermelha, Piauí, Brazil
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Marques, Ricardo

; Garda, Adrian A.

; Furtado, Adriana P.

; Bruinjé, Andre C.

; Protázio, Arielson dos S.

; de Carvalho, Breno F.

; Vieira, Cecília R.

; Gomes, Dandara

; Pantoja, Davi L.

; Figueiredo, Diainara da S.

; Shepard, Donald B.

; Camurugi, Felipe

; Coelho, Felipe E. A.

; Magalhães, Felipe M.

; Caetano, Gabriel H. O.

; Colli, Guarino R.

; Paulino, Henrique M.

; Carvalho, Izabelle T. S.

; Graciene, Joedma

; Alvarenga, Júlio M.

; Clay, Natalie A.

; Albuquerque, Ralph L.

; Bosque, Renan J.

; Faria, Renato

; da Silveira-Filho, Ricardo R.

; Mângia, Sarah

; Cavalcante, Vitor H. G. L.

; Vieira, Washington L. S.

; da Silva, Willianilson P.

; Soares, Yan F. F.

; Mesquita, Daniel O.

Biota Neotropica

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2023, Volume 23 N. 4 elocation e20231520

Abstract: En Pt | Text: En Pt | PDF: En | PDF: Pt

Abstract It is repeatedly stressed the need to characterize the extant biodiversity in tropical ecosystems. However, inventory studies are still progressing slowly in dry ecosystems, leading to the underestimation of their true biodiversity and hindering conservation efforts. In this study, we present primary and secondary data, along with an updated list of amphibians and reptiles from two localities in the São Francisco-Gurguéia region in Piauí. Additionally, we compare the species composition between nine areas within the Caatinga, which were sampled using standardized methods over the past ten years, to examine broader spatial patterns of community composition. To survey reptiles and amphibians, we employed similar methods and sampling efforts in two areas within the Serra das Confusões National Park (SCNP) region. Our surveys recorded a total of 73 species of amphibians and reptiles, of which 24 are new distribution records for the SCNP region. Consequently, our findings increase the known herpetofauna in the region to 94 species. Despite their proximity, the two sites in the SCNP region exhibited only 42% similarity in species composition, and they differed significantly from other areas within the Caatinga. Furthermore, even the closer Caatinga areas presented differences in species composition, highlighting the necessity to evaluate biodiversity across the landscape and contribute to understanding biogeographic patterns.

Resumo É repetidamente enfatizada a necessidade de caracterizar a biodiversidade vivente em ecossistemas tropicais. No entanto, os estudos de inventário ainda estão progredindo lentamente em ecossistemas secos, levando à subestimação de sua verdadeira biodiversidade e dificultando os esforços de conservação. Neste estudo, apresentamos dados primários e secundários, juntamente com uma lista atualizada de anfíbios e répteis de duas localidades na região de São Francisco-Gurguéia, do Piauí. Além disso, comparamos a composição de espécies entre nove áreas dentro da Caatinga, que foram amostradas usando métodos padronizados nos últimos dez anos, para examinar padrões espaciais mais amplos de composição da comunidade. Para estudar répteis e anfíbios, utilizamos métodos e esforços de amostragem semelhantes em duas áreas na região do Parque Nacional da Serra das Confusões (PNSC). Nossos levantamentos registraram um total de 73 espécies de anfíbios e répteis, das quais 24 são novos registros de distribuição para a região do PNSC. Consequentemente, nossos resultados aumentam a herpetofauna conhecida na região para 94 espécies. Apesar da proximidade, os dois locais na região do PNSC exibiram apenas 42% de similaridade na composição de espécies e diferiram significativamente de outras áreas dentro da Caatinga. Mesmo áreas mais próximas da Caatinga apresentaram diferenças na composição de espécies, destacando a necessidade de avaliar a biodiversidade em toda a paisagem e contribuir para a compreensão de padrões biogeográficos.

https://doi.org/10.1590/1676-0611-bn-2023-1520

Simultaneous Quantification of Amorphous and Crystalline Valsartan in Tablets Using Raman Spectroscopy and Chemometrics Tools
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Domingos, Rafael C.

; Pinheiro, Adonilson F.

; Alvarenga Jr., Benedito R. de

; Carneiro, Renato L.

; Farias, Marco A. S.

Journal of the Brazilian Chemical Society

Journal Metrics
- Sobre o periódico
- SciELO Analytics

feb 2022, Volume 33 N. 2 Pages 157 - 162

Abstract: En | Text: En | PDF: En

Valsartan is an antihypertensive active pharmaceutical ingredient (API), it is used in the amorphous state in the commercial products. As amorphous materials are metastable, amorphous valsartan can crystallize to valsartan E, promoting changes in the dissolution and bioavailability of the drug. Tablets containing metastable forms of APIs need special conditions for transport and storage in order to avoid crystallization (from amorphous state) or polymorphic transitions (from less stable crystalline structures). A multivariate calibration model based on interval partial least squares (iPLS) regression allied to net analyte signal (NAS) algorithm was built to simultaneously quantify amorphous (VAL-AM) and crystalline (VAL-E) valsartan. Mixtures of VAL-AM and VAL-E were used to produce tablets in order to simulate the crystallization of VAL-AM in a range from 0 to 100% of conversion. The calibration set included 11 samples and 5 samples were used as the external validation set. The following parameters of merit (POM) were obtained for both polymorphs in order to evaluate the calibration model quality: root mean square error (RMSE) for cross validation (RMSECV), validation (RMSEV) and calibration (RMSEC), sensitivity (SEN), selectivity (SEL), analytical sensitivity (γ), inverse analytical sensitivity (γ−1), limit of detection (LOD) and limit of quantification (LOQ).

https://doi.org/10.21577/0103-5053.20210132

Schools reopening and the COVID-19 pandemic: a case study from Macaé, Rio de Janeiro, Brazil
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

POZZOBON, ALLAN P. B.

; PETRY, ANA C.

; ZILBERBERG, CARLA

; BARROS, CINTIA M. DE

; NEPOMUCENO-SILVA, JOSÉ L.

; FEITOSA, NATÁLIA M.

; GOMES NETO, LUPIS R.

; RODRIGUES, BRUNO C.

; BRINDEIRO, RODRIGO M.

; NOCCHI, KEITY JAQUELINE C.V.

; MURY, FLAVIA B.

; SOUZA-MENEZES, JACKSON DE

; SILVA, MANUELA L. DA

; MEDEIROS, MARCIO JOSÉ DE

; GESTINARI, RAQUEL S.

; ALVARENGA, ALESSANDRA S. DE

; SILVA, CARINA A.O.

; SANTOS, DANIELE G. DOS

; SILVESTRE, DIEGO HENRIQUE

; SOUSA, GRAZIELE F. DE

; ALMEIDA, JANIMAYRI F. DE

; SILVA, JHENIFER N. DA

; BRANDÃO, LAYZA M.

; DRUMMOND, LEANDRO O.

; CARPES, RAPHAEL M.

; SANTOS, RENATA C. DOS

; PORTAL, TAYNAN M.

; TANURI, AMILCAR

; NUNES-DA-FONSECA, RODRIGO

Anais da Academia Brasileira de Ciências

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2022, Volume 94 elocation e20211361

Abstract: En | Text: En | PDF: En

Abstract Since the first reported case of COVID-19 in Brazil, the public and private educational system started to close. Up to November 2020, scientific discussions about the return of schooling activities have been rarely performed by the national scientific community and police-makers. The great delay of school returning in Brazil contrasts with successful international strategies of school reopening worldwide and seems counterintuitive with the reopening of non-essential activities. Here, important issues to be considered before and during school reopening are reviewed and discussed. COVID-19 testing is essential to avoid disease spreading, but high cost of individual RT-qPCRs impairs an extensive testing strategy for school returning. To reduce costs and increase the speed of diagnosis, we tested the efficiency of a pooled-sample PCR strategy in a cohort of the educational staff in the city of Macaé/RJ, finding five asymptomatic individuals (0,66%) among the 754 people tested. Thus, a polled-sample PCR testing strategy of the educational staff might prevent infection spreading in schools at a reasonable cost. We discuss how our test strategy could be coupled with internationally recognized safety rules to allow for a safe school return and how countries from different world regions are dealing with educational activities during COVID-19 pandemic.

https://doi.org/10.1590/0001-3765202220211361

USE OF REMOTELY PILOTED AIRCRAFTS FOR THE APPLICATION OF PLANT PROTECTION PRODUCTS
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Cunha, João P. A. R. da

; Alvarenga, Cleyton B. de

; Rinaldi, Paula C. N.

; Marques, Matheus G.

; Zampiroli, Renan

Engenharia Agrícola

Journal Metrics
- Sobre o periódico
- SciELO Analytics

apr 2021, Volume 41 N. 2 Pages 245 - 254

Abstract: En | Text: En | PDF: En

ABSTRACT The use of remotely piloted aircrafts (RPAs) to apply plant protection products has grown a lot in agriculture worldwide. However, little research data are available regarding the efficiency and safety of this method, especially in Brazil. Thus, this review aimed to present the current scenario of scientific research involving RPAs in the application of pesticides. Several factors interfere with the quality of this type of application. Among them are height and flight speed, droplet generator elements, application rate, and spray solution properties. In general, applications have been performed between 1.0 m and 3.0 m of height and 1.0 m s-1 and 7.0 m s-1 of speed. As for the droplet generator element, there is still no clarity as to the ideal system. Efficacy studies involving RPA applications demonstrate the potential of this method in replacing applications performed mainly by using knapsack equipment in an effort to reduce occupational risks. However, it is essential to observe the advantages of RPA use, while also taking into account the risk of drift. The aerodynamic effect in the droplets, qualified personnel, appropriate formulations, regulations, and details in labels are challenges that still need to be addressed for this new technology to be successful.

https://doi.org/10.1590/1809-4430-eng.agric.v41n2p245-254/2021 406 downloads

Land-use changes affect the functional structure of stream fish assemblages in the Brazilian Savanna
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Alvarenga, Ludmilla R. P.

; Pompeu, Paulo S.

; Leal, Cecília G.

; Hughes, Robert M.

; Fagundes, Daniela C.

; Leitão, Rafael P.

Neotropical Ichthyology

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2021, Volume 19 N. 3 elocation e210035

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Investigamos os mecanismos envolvidos na relação entre mudanças de uso da terra e biodiversidade aquática, utilizando a ictiofauna de riachos do Cerrado como modelo de estudo. Testamos a predição de que a degradação da paisagem reduz a heterogeneidade ambiental e muda os tipos predominantes de habitat, por sua vez, diminuindo a diversidade e alterando a identidade funcional de comunidades de peixes. Amostramos 40 riachos da bacia do Alto Rio Paraná, e avaliamos as condições da drenagem e do habitat físico local. Em seguida, conduzimos uma análise ecomorfológica para caracterizar funcionalmente todas as espécies (36) e quantificar diferentes facetas da estrutura funcional das comunidades. Detectamos múltiplos caminhos de impacto das alterações da paisagem sobre a ictiofauna. A degradação das bacias de drenagem reduziu complexidade do leito e heterogeneidade no sombreamento pelo dossel, diminuindo especialização e divergência funcional das comunidades. Alterações na paisagem também reduziram volume de água e quantidade de pedras grandes nos riachos, resultando em diminuição na abundância de espécies de maior porte e com atributos morfológicos que favorecem a natação na coluna d’água. Concluímos que a intensificação dos usos da terra causa alterações significativas para a biodiversidade aquática no Cerrado, reforçando a necessidade de especial atenção a este hotspot global.

Abstract We investigated the mechanisms involved in the relationship between land-use changes and aquatic biodiversity, using stream fish assemblages of the Brazilian Savanna (i.e., Cerrado) as a study model. We tested the prediction that landscape degradation would decrease environmental heterogeneity and change predominant physical-habitat types, which in turn would decrease the functional diversity and alter the functional identity of fish assemblages. We sampled fish from 40 streams in the Upper Paraná River basin, and assessed catchment and instream conditions. We then conducted an ecomorphological analysis to functionally characterize all species (36) and quantify different facets of the functional structure of assemblages. We detected multiple pathways of the impacts from landscape changes on the fish assemblages. Catchment degradation reduced the stream-bed complexity and the heterogeneity of canopy shading, decreasing assemblage functional specialization and divergence. Landscape changes also reduced the water volume and the amount of large rocks in streams, resulting in decreased abundances of species with large bodies and with morphological traits that favor swimming in the water column. We conclude that land-use intensification caused significant changes in aquatic biodiversity in the Cerrado, reinforcing the need to pay special attention to this global hotspot.

https://doi.org/10.1590/1982-0224-2021-0035 178 downloads

Synthesis and Evaluation of Nematicidal Activity of Compounds Derived from Norbornadiene
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Gomes, Anni C. S.

; Demuner, Antonio J.

; Alvarenga, Elson S.

; Gondim, João P. E.

; Fonseca, Andressa R.

; Buonicontro, Dalila S.

; Pilau, Eduardo J.

; Silva, Evandro

Journal of the Brazilian Chemical Society

Journal Metrics
- Sobre o periódico
- SciELO Analytics

sep 2020, Volume 31 N. 9 Pages 1805 - 1814

Abstract: En | Text: En | PDF: En

Nematode is a major problem in agriculture, the effective way to control this pest is through chemical control, but the efficient molecules present in the market have great toxicity to mammals and birds. Thus, there is a constant demand for the development of new nematicide molecules. This study describes the synthesis of 21 novel esters derived from norbornadiene and evaluation of their potential activity against Meloidogyne javanica. The esters 5-25 presented 50% mortality of the nematodes. The acid 3 and the ester 4 caused 96 and 93% mortality of the nematodes, respectively. The lethal concentration to kill 50% of the nematodes (LD50) were determined as being 11.8 µg mL-1 for the acid 3 and 99.4 µg mL-1 for the ester 4. According to the results obtained it is believed that polarity seems to be a key factor for the higher activity of compound 3 compared to structurally similar ester derivatives.

https://doi.org/10.21577/0103-5053.20200067 313 downloads

WATER HARDNESS AND pH IN THE EFFECTIVENESS OF GLYPHOSATE FORMULATIONS
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Cunha, João P. A. R. da

; Palma, Roxanna P.

; Oliveira, Arthur C. de

; Marques, Matheus G.

; Alvarenga, Cleyton B. de

Engenharia Agrícola

Journal Metrics
- Sobre o periódico
- SciELO Analytics

aug 2020, Volume 40 N. 4 Pages 555 - 560

Abstract: En | Text: En | PDF: En

ABSTRACT The hardness and pH of the spray water can interfere with the weed control effectiveness with herbicides, but it is not clear the magnitude of this interference, mainly associating different levels of pH and hardness to different glyphosate formulations. This study aimed to evaluate the influence of hardness and pH, in association, of the water used in the application of two glyphosate formulations on the weed control effectiveness. The experiment was conducted in duplicate, in areas with a predominance of Digitaria horizontalis, under a randomized block design with a 4×4×2+1 factorial scheme, composed of four water hardness levels (70, 110, 230, and 430 ppm CaCO3), four pH levels (3.5, 4.5, 5.5, and 6.5), two glyphosate formulations (ammonium salt and potassium salt), and control without application, with four repetitions. The physicochemical characteristics of the spray solutions and the weed control effectiveness were evaluated at 7, 14, and 21 days after application (DAA). The water pH at the studied range did not interfere with the control effectiveness. The increase in hardness reduced the control at 7 DAA, but this difference was not noticed after 21 DAA. Glyphosate ammonium salt promoted higher control of D. horizontalis than that with potassium salt, regardless of water hardness and pH.

https://doi.org/10.1590/1809-4430-eng.agric.v40n4p555-560/2020 898 downloads

Matemática Educativa, transversalidad y COVID-19
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics

Cantoral, R.

; Ríos Jarquín, W.

; Reyes Gasperini, D.

; Cantoral Uriza, E. A.

; Barrios, E.

; Fallas Soto, R.

; Castillo Bárcena, D.

; Cantoral Farfán, E

; Galo Alvarenga, S.

; Flores García, R.

; Paredes Cancino, C.

; García Zaragoza, V.

; Bonilla Solano, A.

Revista latinoamericana de investigación en matemática educativa

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2020, Volume 23 N. 1 elocation 00006

Abstract: Es | Text: Es | PDF: Es

Resumen Este artículo relaciona nociones de la Matemática Educativa con la transversalidad de los saberes matemáticos en situaciones de pandemia por coronavirus. Se analiza un fenómeno social en el ámbito de la salud desde una mirada académica para la construcción de diálogos sobre las implicaciones de las acciones de política pública que la población lleva a cabo. Las reflexiones propuestas dejan ver el papel que juega el pensamiento matemático en la comprensión de la situación, las medidas de carácter preventivo y los problemas que de este se deriven; todo ello conlleva a la consideración de la noción de aula extendida. Así, el desarrollo del pensamiento habrá de entenderse más allá que la capacidad de resolución de problemas.

817 downloads

10.

Computational algorithm for the verification of reinforced concrete sections in fire situation
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

PADRE, E. P. G.

; RIBEIRO, J. C. L.

; ALVARENGA, R. C. S. S.

; SILVA, R. C.

Revista IBRACON de Estruturas e Materiais

Journal Metrics
- Sobre o periódico
- SciELO Analytics

aug 2019, Volume 12 N. 4 Pages 932 - 955

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo As estruturas de concreto armado podem ter sua capacidade resistente reduzida devido à degradação de suas propriedades mecânicas com a temperatura, aumentando o risco de colapsos estruturais. Assim, o dimensionamento de uma estrutura deve considerar seu comportamento em temperatura ambiente e em situação de incêndio (ABNT NBR 14432:2001). Neste trabalho, apresenta-se o desenvolvimento de um algoritmo para verificação da resistência de seções quaisquer de concreto armado à flexão composta oblíqua em temperatura ambiente e em incêndio. Para isso, implementou-se um algoritmo integrador de tensões a partir do perfil de deformações da seção segundo a ABNT NBR 15200:2012, vinculado com um gerador de malhas de elementos finitos e com um algoritmo de análise térmica. Na validação do programa desenvolvido, denominado Pisafo, compararam-se os resultados obtidos com os apresentados na literatura: obtidos em experimentos, com diferenças de até 28,5%, e com programas consagrados, com diferenças de até -14,8%. As maiores variações em relação aos experimentos podem ser atribuídas às diferenças entre as propriedades térmicas do concreto nos experimentos com as prescritas em normas utilizadas no programa e à não consideração do spalling na análise computacional.

Abstract Reinforced concrete structures may have reduced strength due to the degradation of their mechanical properties by temperature. This can increase the risk of structural collapses. Thus, the structural design should consider its behavior at room temperature and in fire situation (ABNT NBR 14432:2001). This study presents the development of an algorithm to verify the strength of any reinforced concrete sections subjected to unsymmetrical bending at room temperature and in fire situation. For this purpose, a stress integration algorithm was implemented from the strain profile of the section according to ABNT NBR 15200:2012, linked to a finite element mesh generator and a thermal analysis algorithm. For validation of the developed program, called Pisafo, the results obtained were compared with those in the technical literature: obtained in experiments (with differences of up to 28.5%) and with recognized software solutions (with differences of up to -14.8%). The largest variations in relation to the experiments can be attributed to the differences between the thermal properties of the concrete in the experiments with those prescribed in the technical standards used by the program and the non-consideration of spalling in the computational analysis.

https://doi.org/10.1590/s1983-41952019000400012 1215 downloads

11.

Nasopalatine duct cyst - diagnosis, treatment and postoperative complications: report of two cases
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Oliveira, Leandro J.

; Leão, Priscila Laiza R.

; Alvarenga, Roberto R.

; Horta, Martinho C. R.

; Souza, Paulo Eduardo A.

Jornal Brasileiro de Patologia e Medicina Laboratorial

Journal Metrics
- Sobre o periódico
- SciELO Analytics

nov 2017, Volume 53 N. 6 Pages 407 - 413

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

RESUMO Os objetivos deste estudo foram relatar dois casos de cisto do ducto nasopalatino e rever a literatura pertinente. No primeiro caso, a lesão media aproximadamente 1,5 cm e, no segundo, 3 cm, ambas caracterizadas por tumefação localizada no palato duro. Os dois casos apresentaram imagem radiolúcida unilocular na região do forame incisivo. O diagnóstico foi cisto do ducto nasopalatino, realizado por meio de biópsia excisional e exame anatomopatológico. O segundo paciente apresentou infecção pós-operatória tardia, quatro semanas após a cirurgia, sendo submetido a antibioticoterapia e drenagem. Os dois pacientes foram acompanhados por mais de 30 meses, sem sinais de recidiva.

ABSTRACT The objectives of this study were to report two cases of nasopalatine duct cyst and to review the relevant literature. In the first case, the lesion was approximately 1.5 cm in size and in the second case 3 cm, both characterized by localized swelling in the hard palate. The two cases presented a radiolucent unilocular image in the region of the incisive foramen. The diagnosis was nasopalatine duct cyst, established by excisional biopsy and anatomopathological examination. The second patient presented a late postoperative infection, four weeks after surgery, and was submitted to antibiotic therapy and drainage. Both patients were followed for more than 30 months, with no signs of recurrence.

https://doi.org/10.5935/1676-2444.20170066 28564 downloads

12.

Storage of Calophyllum brasiliense Cambess. seeds
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Nery, F. C.

; Prudente, D. O.

; Alvarenga, A. A.

; Paiva, R.

; Nery, M. C.

Brazilian Journal of Biology

Journal Metrics
- Sobre o periódico
- SciELO Analytics

jul 2017, Volume 77 N. 3 Pages 431 - 436

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Calophyllum brasiliense é uma espécie nativa do Brasil e está na lista de espécies recomendadas para o reflorestamento de áreas degradadas, além de possuir propriedades medicinais e madeireiras. Sua propagação se dá principalmente via sementes, as quais, em função das suas características recalcitrantes, apresentam dificuldade de conservação, devido a alterações no seu potencial fisiológico ao longo do armazenamento. Visando contribuir com a ampliação de seu cultivo, uso racional e conservação, objetivou-se investigar o comportamento das sementes de C. brasiliense durante 12 meses de armazenamento. Testou-se diferentes embalagens (papel, alumínio e polietileno) e condições ambientais (câmara fria e temperatura ambiente), avaliando-se trimestralmente a germinação, viabilidade e vigor. Com base nos resultados obtidos conclui-se que o acondicionamento em embalagem de polietileno e o armazenamento em câmara fria proporcionou a melhor condição para a conservação das sementes, mantendo essas viáveis por um período de nove meses.

Abstract Calophyllum brasiliense is a species native to Brazil and has potential for use in the timber industry, in the reforestation of degraded areas, besides having medicinal properties. Its propagation is mainly by seeds which, depending on their recalcitrant characteristics, leads to difficulty in conservation, due to changes in its physiological potential during storage. Aiming to contribute to the expansion of its cultivation, rational use and conservation, the objective of this study was to investigate the behavior of C. brasiliense seeds during storage. Different packings (paper, aluminum and polyethylene) and environmental conditions (room temperature and cold chamber) were quarterly tested over 12 months, by evaluating germination viability and vigor. Based on the results, it was concluded that packaging in polyethylene and freezer storage provided the best conditions for the conservation of seeds, keeping them viable for a period of nine months.

https://doi.org/10.1590/1519-6984.08115 1071 downloads

13.

Numerical and experimental evaluation of masonry prisms by finite element method
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

SANTOS, C. F.R.

; ALVARENGA, R. C. S. S.

; RIBEIRO, J. C. L.

; CASTRO, L. O

; SILVA, R. M.

; SANTOS, A.A.R.

; NALON, G. H.

Revista IBRACON de Estruturas e Materiais

Journal Metrics
- Sobre o periódico
- SciELO Analytics

apr 2017, Volume 10 N. 2 Pages 477 - 508

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo No presente trabalho desenvolveram-se ensaios experimentais e modelos numéricos capazes de representar o comportamento mecânico de prismas confeccionados com blocos de concreto comuns e de alta resistência. Foram realizados ensaios experimentais de prismas e, para a análise numérica, adotou-se como estratégia de modelagem, a micromodelagem detalhada, onde cada material (bloco e argamassa) foi representado por suas propriedades mecânicas. A validação dos modelos numéricos foi realizada com base em resultados experimentais realizados. Verificou-se que os valores obtidos numericamente de resistência à compressão e módulo de elasticidade diferem 5% em relação aos valores observados experimentalmente. Ainda foram avaliados quais os mecanismos responsáveis pela ruptura dos prismas, comparando-se tanto com o comportamento verificado nos ensaios, quanto com os descritos na literatura. Por meio dos resultados experimentais conclui-se que os modelos numéricos foram capazes de representar tanto as propriedades mecânicas quanto os mecanismos responsáveis pela ruptura.

Abstract This work developed experimental tests and numerical models able to represent the mechanical behavior of prisms made of ordinary and high strength concrete blocks. Experimental tests of prisms were performed and a detailed micro-modeling strategy was adopted for numerical analysis. In this modeling technique, each material (block and mortar) was represented by its own mechanical properties. The validation of numerical models was based on experimental results. It was found that the obtained numerical values of compressive strength and modulus of elasticity differ by 5% from the experimentally observed values. Moreover, mechanisms responsible for the rupture of the prisms were evaluated and compared to the behaviors observed in the tests and those described in the literature. Through experimental results it is possible to conclude that the numerical models have been able to represent both the mechanical properties and the mechanisms responsible for failure.

https://doi.org/10.1590/s1983-41952017000200010 4192 downloads

14.

Experimental evaluation of the interaction between strength concrete block walls under vertical loads
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

CASTRO, L. O.

; ALVARENGA, R. C. S. S.

; SILVA, R. M.

; RIBEIRO, J. C. L.

Revista IBRACON de Estruturas e Materiais

Journal Metrics
- Sobre o periódico
- SciELO Analytics

oct 2016, Volume 9 N. 5 Pages 643 - 681

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Este trabalho tem como objetivo avaliar a interação entre paredes de alvenaria estrutural de blocos de concreto de alta resistência, sob ações verticais. Foram ensaiadas duas séries de paredes com flanges intertravadas, em formato "H" em escala real e com amarração direta, sendo uma série composta de três espécimes com a parede central (alma) apoiada e a outra série de três espécimes sem apoio na alma. A carga foi aplicada na parede central e através de transdutores de deslocamento foram monitorados os deslocamentos verticais em dezoito pontos do conjunto de paredes. Os resultados mostram que os valores de carga estimados para os flanges das paredes com apoio central foram próximos daqueles suportados pelos flanges das paredes sem apoio central, nas quais ocorrem 100% de transferência de carga para os mesmos. As taxas de transferência médias, calculadas com base na relação de deformações no trecho superior e inferior para o conjunto de paredes com apoio central, foram de 37,65% e 77,30%, respectivamente, mostrando que existe transferência de carga da parede central (alma) para os flanges, particularmente no trecho inferior do conjunto de paredes. Assim, há um indicativo de que a distribuição de forças verticais pode ser considerada em projetos de edifícios para cargas de serviço, como no método de grupo isolado de paredes. Com relação ao comportamento último das paredes com flanges com apoio na alma, a ruptura ocorre no topo da alma, local onde ainda não ocorre transferência de forças verticais entre paredes adjacentes, neste caso o método de paredes isoladas para a estimativa da carga de ruptura seria adequado.

Abstract This paper aims to evaluate the interaction between structural masonry walls made of high performance concrete blocks, under vertical loads. Two H-shaped flanged wall series, all full scale and using direct bond, have been analyzed experimentally. In one series, three flanged-walls were built with the central wall (web) supported and, in the other one, three specimens were built without any support at the central web. The load was applied on the central wall and vertical displacements were measured by means of displacement transducers located at eighteen points in the wall-assemblages. The results showed that the estimated load values for the flanges were close to those supported by the walls without central support, where 100% of the load transfer to the flanges occur. The average transfer load rate calculated based on the deformation ratio in the upper and lower section of the flanged-walls, with the central web support, were 37.65% and 77.30%, respectively, showing that there is load transfer from the central wall (web) toward the flanges, particularly in the lower part of the flanged walls. Thus, there is indication that the distribution of vertical loads may be considered for projects of buildings for service load, such as in the method of isolated walls group. For estimation of the failure load, the method that considers the walls acting independently showed better results, due to the fact that failure started at the top of the central wall, where there is no effect of load distribution from the adjacent walls.

https://doi.org/10.1590/S1983-41952016000500002 2158 downloads

15.

Seedling survival of Handroanthus impetiginosus (Mart ex DC) Mattos in a semi-arid environment through modified germination speed and post-germination desiccation tolerance
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Martins, J. R.

; Edvaldo, A. A. S.

; Alvarenga, A. A.

; Rodrigues, A. C.

; Ribeiro, D. E.

; Toorop, P. E.

Brazilian Journal of Biology

Journal Metrics
- Sobre o periódico
- SciELO Analytics

nov 2015, Volume 75 N. 4 Pages 812 - 820

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo A germinação rápida e uniforme geralmente pode apresentar riscos para a população de plantas caso a precipitação ocorra de maneira intermitente, provocando seca e morte das plântulas. Handroanthus impetiginosus pode ser encontrado em uma grande variedade de biomas no Brasil. A germinação e o crescimento inicial das plântulas de Handroanthus impetiginosus foram estudadas para compreender como as sementes germinadas sobrevivem nestas condições. Acessos de quatro biomas que apresentam secas sazonais foram amostrados. A precipitação, no início da estação chuvosa na Caatinga, um bioma semi-árido, é menos previsível e o número de dias secos consecutivos por intervalo de seca, nos primeiros quatro meses da estação chuvosa, foi maior do que nos outros biomas estudados. Plantas do bioma Caatinga produzem sementes mais espessas e essa característica está associada com uma germinação lenta e com a inibição osmótica maior da germinação através dos acessos, formando um mecanismo para evitar o estresse. Tolerância à dessecação em sementes germinadas foi superior no bioma Caatinga e que podem ser reinduzida em acesso com uma precipitação mais regular (Cerrado e na zona de transição), mas manteve-se baixa no acesso Cerradão, formando assim um mecanismo para evitar o estresse. Produção de raízes adventícias foi observada nos indivíduos estudados de todos os quatro biomas, mesmo quando as raízes primárias não sobreviveram à dessecação, formando um mecanismo adicional de tolerância ao estresse. Assim, foi observado estratégias para evitar o estresse e mecanismos de tolerância ao estresse em sementes e sementes germinadas associada com padrões de precipitação nos diferentes biomas estudados. Estes mecanismos podem favorecer o estabelecimento das plântulas de forma rápida quando as condições são adequadas e permitirem a sobrevivência de plântulas quando as condições são adversas.

Abstract Uniform rapid seed germination generally forms a great risk for the plant population if subsequent intermittent precipitation causes desiccation and seedling death. Handroanthus impetiginosus can be found commonly in a wide range of biomes within Brazil including those that are semi-arid. Germination and early growth was studied to understand how germinated seeds survive under these stringent conditions. Accessions were sampled from four seasonally dry biomes in Brazil. Precipitation at the start of the rainy season in the Caatinga, a semi-arid biome, is less predictable and the number of successive dry days per dry interval in the first four months of the rainy season was higher than in the other studied biomes. Plants from the Caatinga produced thicker seeds and this trait concurred with slow germination and stronger osmotic inhibition of germination across the accessions, forming a stress avoidance mechanism in the Caatinga. Post-germination desiccation tolerance was high in the Caatinga accession, could be re-induced in accessions from biomes with more regular precipitation (Cerrado and transition zone), but remained poor in the Cerradão accession; thus forming a stress tolerance mechanism. Production of adventitious roots ascertained survival of all tested individuals from all four locations, even if protruded radicles did not survive desiccation, forming an additional stress tolerance mechanism. A sequence of stress avoidance and stress tolerance mechanisms in seeds and germinated seeds was associated with precipitation patterns in different biomes. These mechanisms purportedly allow rapid seedling establishment when conditions are suitable and enable survival of the young seedling when conditions are adverse.

https://doi.org/10.1590/1519-6984.23413 2505 downloads

Showing

itens per page

Page of 3 Next

Select one or more results

All Alphabetic

Results

Comparative chart Download CSV

Statistics of

Send result

To*

Use ; (semicolon) to insert more emails.

Send to email

This page

Selected records

All references (max. 300)

Your email

Subject

Comments

Export format:

RIS (for EndNote, ProCite, Reference Manager, RefWorks, Citavi, etc.)

BibTeX

Citation

CSV (for Excel, etc)

Export:

This page

Selected itens

All references (max. 2000)

Sem resultados

No documents were found for your search

Glossary and search help

You can enrich your search in a very simple way. Use the search indexes combined with the connectors (AND or OR) and specify more your search.

For example, if you want to search for articles about
cases of dengue in Brasil in 2015, use:
ti:dengue and publication_year:2015 and aff_country:Brasil

See below the complete list of search indexes that can be used:

Index code	Element
ti	article title
au	author
kw	article keywords
subject	subject (title words, abstract and keywords)
ab	abstract
ta	journal short title (e.g. Cad. Saúde Pública)
journal_title	journal full title (e.g. Cadernos de Saúde Pública)
la	publication language code (e.g. pt - Portuguese, es - Spanish)
type	document type
pid	publication identifier
publication_year	publication year of publication
sponsor	sponsor
aff_country	country code of the author's affiliation
aff_institution	author affiliation institution
volume	article volume
issue	article issue
elocation	elocation
doi	DOI number
issn	journal ISSN
in	SciELO colection code (e.g. scl - Brasil, col - Colômbia)
use_license	article usage license code

SciELO - Scientific Electronic Library Online
Rua Dr. Diogo de Faria, 1087 – 9º andar – Vila Clementino 04037-003 São Paulo/SP - Brasil
Email: scielo@scielo.org

All the contents of this site www.scielo.br, except where otherwise noted, is licensed under a Creative Commons Attribution License.
more »