bluuebunny/crossref_metadata_2025 huggingface dataset:
Obtaining hydroxyapatite with different precursors for application as a biomaterial
Authors: Farias K. A. S. , Sousa W. J. B. , Cardoso M. J. B. , Lima R. J. S. , Rodriguez M. A. , Fook M. V. L.
Published: January 2019

Abstract The hydroxyapatite (HAp) is a ceramic biomaterial with wide application in the bone regeneration. It can be obtained by different routes and different precursors. In this study, the synthesis of HAp was carried out by precipitation and subsequent thermal treatment using different calcium precursors: calcium hydroxide from synthetic origin and calcium oxide obtained from the eggshell. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. By SEM, variations of the crystal size and the concentration of agglomerates were observed. FTIR and XRD analyses proved the formation of HAp and how the (mineral and biological) precursors affected the microstructure. The thermal decomposition process of the calcium oxide obtained from the eggshell showed to be more effective for the synthesis of the hydroxyapatite, resulting in more stable morphology and microstructure.
Effect of thermal treatment on the catalytic activity of a Fe-rich bentonite for the photo-Fenton reaction
Authors: Zimmermann B. M. , Silvestri S. , Leichtweis J. , Dotto G. L. , Mallmann E. S. , Foletto E. L.
Published: January 2019

Abstract The objective of this work was to evaluate the degradation of rhodamine B dye from aqueous solution by photo-Fenton reaction under visible irradiation using a Fe-rich bentonite as a catalyst. The material was thermally treated at a low temperature (200 °C) and characterized by XRD, N2 adsorption-desorption isotherms, FTIR, SEM-EDS and XRF. Iron leaching in aqueous solution after the photo-Fenton reaction was evaluated by atomic absorption spectroscopy. The material exhibited a mesoporous structure, containing a specific surface area of 99 m2.g-1. The catalytic results showed significant dye degradation, reaching 95% of decolorization and 72% of mineralization at 300 min of reaction. The catalyst showed high chemical stability in four reaction cycles. Therefore, this thermally treated Fe-rich bentonite can be considered as a promising catalyst in the heterogeneous photo-Fenton reaction for the degradation of rhodamine B from aqueous solution.
Characterization of clays from the State of Paraíba, Brazil for aesthetic and medicinal use
Authors: Buriti B. M. A. B. , Buriti J. S. , Silva I. A. , Cartaxo J. M. , Neves G. A. , Ferreira H. C.
Published: January 2019

Abstract This study aimed to evaluate the potential of clays from the State of Paraíba to be used for medicinal, therapeutic and aesthetic treatments. The samples were characterized by X-ray diffraction, X-ray fluorescence chemical composition, thermogravimetry, differential thermal analysis, laser diffraction granulometric analysis, cation exchange capacity, and antimicrobial activity. Based on the study, it was concluded that the clays from the State of Paraíba had properties similar to those of commercial clay. The antimicrobial evaluation revealed that the samples showed no activity against the three bacterial strains of clinical interest: Staphylococcus epidermidis ATCC 12 228, Staphylococcus aureus ATCC 25 923, and Escherichia coli ATCC 25 922. Finally, it was concluded that the clays studied have the potential for technological applications in medicinal, therapeutic, and aesthetic treatments, and as raw material for obtaining biomaterials, due to their stability and biological safety.
Development and characterization of sustainable lightweight geopolymer composites
Authors: Khater H. M.
Published: January 2019

Abstract Production of lightweight building materials attract the attention of the scientists worldwide with the need for reducing the structure deadweight, provide better thermal insulation for buildings, and cost less to transport. The current work focused on the production of lightweight geopolymer composites by the incorporation of aluminum powder and aluminum slag in various ratios for water-cooled slag/kaolinite sand composite; the activators used were 6% of equal ratio from sodium hydroxide and sodium silicate. The properties of the produced lightweight geopolymer composites were studied by measurement of compressive strength, bulk density, water absorption, FTIR, XRD and SEM imaging. Results showed the enhancement for both physicomechanical and microstructural characteristics with using aluminum powder and aluminum slag forming lightweight composites with densities below 2.15 g/cm3 depending on the studied mix composition.
O equilíbrio estelar e a existência de uma massa máxima para as estrelas
Authors: Bandecchi M. , Horvath J.E. , Bretones P.S.
Published: January 2019

Resumo As condições simultâneas de equilíbrio Virial e equilíbrio hidrostático determinam a existência de soluções para os modelos estelares mais simples. Utilizando estes dois conceitos mostramos que é possível caracterizar o fim da seqüência estelar observando o comportamento da pressão do gás e a radiação, e apontamos que este valor coincide dentro das incertezas com a máxima massa diretamente inferida para estrelas reais.
A nova definição do quilograma em termos da constante de Planck
Authors: Damaceno Luiz Paulo , Mascarin Richard , Nogueira João Marcelo Pereira , Magalhães Daniel Varela , Bagnato Vanderlei Salvador
Published: January 2019

Resumo A partir de 2019, a unidade de massa do Sistema Internacional de Unidades (SI), o quilograma, terá sua definição modificada. Deixará de ser o artefato metálico guardado na sede do BIPM, nos arredores de Paris, para ser baseado na constante de Planck (h). Qual é a necessidade desta mudança? E como as medidas são realizadas? São algumas das perguntas que respondemos nesta comunicação, onde descrevemos a operação do experimento denominado Balança de Watt utilizado para a nova maneira de realizar a unidade de massa. Também detalhamos como montamos uma Balança para fins didáticos, utilizada em apresentações sobre o tema. O tópico é de interesse de todos, mas em especial para alunos que recebem aulas de física em qualquer uma das áreas de formação.
Determinação da densidade de líquidos imiscíveis pelo princípio de Stevin
Authors: Gomes Andreia Vaz , Amaral Elessandra Martins de Souza , Prado Rogério Junqueira
Published: January 2019

Resumo Este artigo apresenta uma sequência didática acompanhada por um aparato experimental de baixo custo e fácil montagem e manuseio, a serem aplicados ao estudo da hidrostática e, particularmente, de uma composição de líquidos imiscíveis, como a água e o óleo. O Princípio de Stevin é utilizado para analisar a densidade de líquidos, tendo como referência a densidade da água (ρ = 1000 kg/m3). O professor nesta proposta tem papel fundamental, pois ele é o mediador de todo processo, para assim construir a relação entre os conceitos já existentes na estrutura cognitiva dos alunos com os novos temas. Os conteúdos físicos foram fundamentados a partir de aula expositiva, discorrendo sobre seus conceitos, história e aplicações no cotidiano, de forma a organizar os conhecimentos prévios dos alunos. Por fim, foi feita a reconciliação integrativa do conceito durante a experimentação, de maneira a melhor proporcionar aprendizagem significativa. Com os resultados, além de observar que, num recipiente qualquer, líquidos de menor densidade se posicionam sobre líquidos de maior densidade, os alunos também determinam a densidade de líquidos imiscíveis, obtendo valores similares aos encontrados na literatura. Por exemplo, determinou-se a densidade do óleo de soja como sendo de 0,87 g/cm3, sendo que o valor aceito é de 0,89 g/cm3 , uma diferença de cerca de 2 %.
Workplace Based Assessment in Obstetrics and Gynecology Clerkship to Detect Learning Gaps
Authors: Coelho Raquel Autran , Medeiros Francisco das Chagas , Peixoto Júnior Arnaldo Aires , Diniz Rosiane Viana Zuza , McKinley Danette , Bollela Valdes Roberto
Published: January 2019

ABSTRACT Background An outcome-based curriculum helps to communicate expectations of performance to students and clinical teachers. The Mini Clinical Evaluation Exercise (mini-CEX) is a useful tool for workplace-based formative assessment. The objective of this study was to use workplace-based assessment and student feedback to evaluate an Obstetrics and Gynecology (Ob&Gyn) clerkship curriculum. Methods A cross-sectional study was conducted with faculty members and medical students in an Ob&Gyn clerkship. The Mini-CEX was introduced into the clerkship assessment system, together with multiple choice question (MCQ) tests. This tool evaluates the history collection, physical examination, clinical judgment, professionalism and humanism, and also gives an overall score at the end of the test. At the end of the rotation, questionnaires were used to collect the students’ perceptions about their skills acquisition during the program. The results of the Mini-CEX, the MCQ test, and questionnaire responses were compared, to determine the extent to which learning objectives were achieved. Results three faculty members assessed 84 medical students using the mini-CEX during the four-month clerkship. The scores for the physical examination and clinical judgment skills were lower, compared to those of the interviewing skills. Based on the students’ feedback, ratings for physical examination and counseling preparation were rated as “inadequate”, especially for the topic breaking bad news. The bivariate correlation between the mini-CEX skills and MCQ test scores showed a positive relationship (r = 0.27). Although they assess different skills on the Muller pyramid, there appears to be a relationship between “Knowing” and “Doing”. These findings will help curriculum managers to identify important gaps in the rotation design and delivery. Based on these results, training in the skills workshop during the first month of the rotation was initiated, in addition to previous simulated training during the third year of medical course. Conclusions The introduction of the mini-CEX offers critical information to identify and refine important curriculum elements in the clinical years. Based on this, physical examination and communications skills training were initiated in the skills workshop.
Infraestrutura para higienização das mãos em um hospital universitário
Authors: Magnago Tânia Solange Bosi de Souza , Ongaro Juliana Dal , Greco Patrícia Bittencourt Toscani , Lanes Taís Carpes , Zottele Caroline , Gonçalves Naiane Glaciele , Andolhe Rafaela
Published: January 2019

Resumo OBJETIVO Avaliar a infraestrutura hospitalar e o conhecimento dos coordenadores sobre a estrutura da unidade para à higienização das mãos. MÉTODO Estudo transversal descritivo realizado em um hospital universitário no Sul do Brasil, entre dezembro de 2016 e janeiro de 2017. Foram avaliadas 18 unidades de internação e entrevistados 16 coordenadores. Utilizou-se o questionário sobre estrutura da unidade para a higienização das mãos da estratégia multimodal da Organização Mundial de Saúde. Utilizou-se a estatística descritiva. RESULTADOS Todas as unidades possuíam preparações alcóolicas, e 93,8% dos dispensadores eram substituídos quando vazios. Observaram-se falta de cartazes ilustrativos, dispensadores de álcool gel, pias em algumas enfermarias, e pouca disponibilidade de dispensadores ao alcance das mãos próximos ao leito/maca do paciente. CONCLUSÕES Constatou-se que os profissionais recebiam instruções para a higienização das mãos e a existência de protocolos. Lacunas foram observadas na infraestrutura das unidades, como a presença de pias e torneiras não adequadas.
Implementação dos núcleos de segurança do paciente e as infecções relacionadas à assistência à saúde
Authors: Cavalcante Elisângela Franco de Oliveira , Pereira Illiana Rose Benvinda de Oliveira , Leite Maria Jalila Vieira de Figueiredo , Santos Alexandy Michel Dantas , Cavalcante Cleonice Andréa Alves
Published: January 2019

Resumo OBJETIVO Verificar a implementação do Núcleo de Segurança do Paciente e sua relação com o controle das Infecções Relacionadas à Assistência à Saúde nos hospitais de Natal. MÉTODO Estudo quantitativo, do tipo transversal. A amostra foi composta por 28 profissionais controladores de infecção de 12 hospitais. Os dados foram coletados entre fevereiro e agosto de 2017, por meio de questionário semiestruturado. RESULTADOS Houve implementação do Núcleo de Segurança do Paciente em nove hospitais. Dentre os protocolos implantados, destacaram-se o de identificação do paciente (66,70%), o de higiene das mãos (50%) e o da prevenção de quedas (50%). Os hospitais com Núcleo afirmaram desenvolver atividades de capacitação em segurança do paciente com os profissionais. 44,5% afirmaram realizar comunicação efetiva. CONCLUSÃO Embora as ações implantadas não cheguem a cumprir integralmente as recomendações da Agência Nacional de Vigilância Sanitária, a maioria dessas ações tem relação direta com o controle das infecções nos serviços.
Effect of abscisic acid on the calcium content for controlling blossom-end rot in tomato under water stress
Authors: Balate Carlos Agostinho , Souza Douglas Correa de , Resende Luciane Vilela , Freitas Sergio Tonetto de
Published: January 2019

ABSTRACT Water stress in tomato plants may cause the incidence of blossom-end rot. This study aimed to analyze the effect of abscisic acid leaf application for increasing the calcium uptake in irrigated tomato (‘Santa Clara' cultivar) in the field, as a possible mechanism of blossom-end rot inhibition. The treatments consisted of four irrigation levels (25 %, 50 %, 75 % and 100 % of the crop water requirements to fulfil the crop evapotranspiration) and two abscisic acid doses (0 mg L-1 and 500 mg L-1). The fruits were harvested at 15 and 30 days after the anthesis and evaluated for calcium content and percentage of blossom-end rot. The application of abscisic acid increased the calcium partition to the distal region of the fruits at 30 days after the beginning of flowering, as well as reduced the incidence of blossom-end rot by 86 %, when compared with plants not treated with abscisic acid. It is possible to conclude that the foliar application of abscisic acid can significantly reduce the incidence of blossom-end rot.
Physalis development according to the growing season in the semi-arid region of the Bahia state, Brazil
Authors: Barroso Natália dos Santos , Fonseca Josandra Souza Teles , Nascimento Marilza Neves do , Pelacani Claudinéia Regina
Published: January 2019

ABSTRACT The Physalis ixocarpa species has an interesting performance in hot and dry regions. However, there has been a lack of information about the influence of edaphoclimatic conditions, during the growing period, on the physical and physicochemical characteristics of the fruits. This study aimed to evaluate the characteristics of ‘purple' and ‘green' fruits of the P. ixocarpa species, according to the growing season, in the semi-arid region of the Bahia state, Brazil. A randomized block design was used, in a 2 x 2 x 5 factorial scheme (variety x growing season x fruit maturation stages), with three replications. The following characteristics were evaluated: color, fresh weight, length, diameter and total soluble solids contents of the fruits. The changes in the characteristics of the fruits follow the same tendency during maturation, for both evaluated varieties, with the best characteristics being observed when the calyx is green, with dry parts, completely expanded and ruptured. The growing season has a significant effect on the characteristics of the fruits, with May to August presenting the best environmental conditions for growing in the semi-arid region of the Bahia state.
Políticas Educacionais e Pesquisas Acadêmicas sobre Dança na Escola no Brasil: um movimento em rede
Authors: Corrêa Josiane Franken , Santos Vera Lúcia Bertoni dos
Published: January 2019

Resumo: O artigo objetiva mapear políticas educacionais, documentos oficiais e trabalhos acadêmicos relacionados à Dança na Escola, a fim de criar um panorama, situando as principais iniciativas públicas e pesquisas envolvidas na busca pela inserção do professor de Dança na instituição escolar no contexto brasileiro. O trabalho caracteriza-se como documental e bibliométrico qualiquantitativo, tendo como recorte temporal o período entre 1990 e 2017. Conclui-se que, para analisar a constituição do campo acadêmico em Dança na Escola no Brasil, é necessário identificar ações que influenciam o desenvolvimento dessa prática, sob a perspectiva de uma visão sistêmica e relacional.
CONSTITUINTE, FINANCIAMENTO E DIREITO À EDUCAÇÃO: A VOZ DOS PROTAGONISTAS
Authors: Martins Paulo de Sena
Published: January 2019

RESUMO: Por meio das vozes dos protagonistas do processo constituinte - a dos parlamentares, em seus discursos no plenário e intervenções nas audiências públicas da Subcomissão da Educação, Cultura e Esportes, e a dos representantes da sociedade civil que compareceram a essas sessões para prestar seu depoimento -, o trabalho resgata o processo de discussão que levou ao capítulo de educação da Constituição de 1988. Esse capítulo trouxe significativos avanços institucionais, no plano jurídico-constitucional, ao consagrar o direito à educação e estabelecer os pilares da política de seu financiamento.
REAFIRMAÇÃO DAS LUTAS PELA EDUCAÇÃO EM UMA SOCIEDADE DESIGUAL?
Authors: Arroyo Miguel Gonzalez
Published: January 2019

RESUMO: O texto retoma como a reafirmação das lutas pela educação em nossa sociedade tão desigual tem sido uma constante a incentivar o pensamento político, social e pedagógico. Destacamos que somos obrigados a perguntar-nos como tem sido pensada a relação entre desigualdade educacional e desigualdade social. Somos obrigados, ainda, a perguntar-nos sobre que mudanças vêm dos grupos sociais vítimas das desigualdades sociais e educacionais nas formas de pensar essa relação. Organizamos a análise em torno das seguintes questões: corrigir as desigualdades sociais pela igualdade educacional? Os Outros, vítimas dessas desigualdades, ficam na espera da igualdade social pela igualdade educacional? Questionam essa relação? O texto destaca que os Outros radicalizam sua produção como desiguais no padrão de inferioridade cognitiva, ética, cultural. Levam a ter sido decretados deficientes em humanidade, consequentemente afirmam outro paradigma pedagógico e outro paradigma de humanidade. De igualdade.
Componentes fenológicos del sistema de cruzamiento monoico de Cnidoscolus spinosus (Euphorbiaceae) en Jalisco
Authors: Bullock Stephen H.
Published: January 2019

Una jerarquía de rasgos fenológicos define las oportunidades de cruzamiento en una población de Cnidoscolus spinosus en una selva tropical caducifolla en el occidente de México. En cualquier árbol dado, las inflorescencias se desarrollan más o menos sicrónicamente y todas presentan flores femeninas y masculinas. Solamente se desarrollan flores femeninas en las posiciones inferiores de ramificación, pero más tarde sólo se desarrollan flores masculinas. El traslapo del periódo de madurez de flores masculinas y femeninas es poco común en una inflorescencia o entre inflorescencias: los árboles son funcionalmente masculinos o femeninos en un momento dado. La sincronía interarbórea puede entonces reducir el éxito de la reproducción. La asincronía se consigue en parte por diferencias en el comienzo de la floración, y también por la varianza en la duración de los ciclos individuales de floración. La presencia de dos o tres ciclos de floración por árbol durante una estación (para la población) aumenta sus oportunidades reproductivas.
Reseña del libro: Ecología de la estación experimental Zoquiapan (Descripción general, vegetación y fauna). Blanco Z., S., y otros, Universidad Autónoma de Chapingo, Departamento de Bosques, México, 1978. 114 pp.
Authors: Pérez-García Martha
Published: January 2019

Reseña de libro
Nota sobre la ortografía correcta de Casimiroa calderonii Chiang et Medrano
Authors: Chiang Fernando
Published: January 2019

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New taxa anda new name in Mexican and Central American Randia (Rubiaceae, Gardenieae)
Authors: Lorence David H. , Dwyer John D.
Published: January 2019

Four new species of Randia are described from Mexico and Central America: R. hidalgensis Lorence, R. lonicerioides Dwyer & Lorence, R. pterocarpa Lorence & Dwyer, and R. vazquezii Lorence & Dwyer. Casasia chiapensis Miranda is transferred to Randia under the new name R. matudae Lorence & Dwyer.
Distribución de Rhynchosporium secalis en el mundo y en México
Authors: Carvajal-Moreno Magda
Published: January 2019

En el presente trabajo se hace una revisión de la distribución de Rhynchosporium secalis (Oud.) Davis, hongo causante de la escaldadura de la cebada, ya que esta enfermedad es de gran importancia para dicho cultivo. El hongo mencionado es de amplia distribución mundial y se encuentra por lo menos en 34 países. En México se encuentra en la parte central del país en los estados de Hidalgo, Puebla, Tlaxcala, México, Jalisco, Zacatecas, Veracruz, Guanajuato, Aguascalientes y Querétaro. También ataca a la cebada del norte de México, causando bajas en Ensenada y Baja California Norte.
Estudios cromosómicos en seis especies mexicanas de comelináceas
Authors: Palomino-Hasbach Guadalupe , Vázquez-Benítez Balbina , Martínez-Almeraya Patricia , Mercado-Ruaro Pedro
Published: January 2019

Se determinaron los números cromosómicos (2n) y se elaboraron los cariotipos de Tradescantia crassifolia Cav. subsp. acaulis (Martens y Galeotti) D. Hunt, Gibasis shiedeana (Kunth) D. Hunt, Cymbispatha commelinoides (Shult. f.) Pichon, Commelina communis L., C. diffusa Burm. f. y C. coelestis Willd. Para T. crassifolia subsp. acaulis , este es el primer registro de número cromosómico y cariotipo. Las especies estudiadas se colectaron en la Reserva Ecológica del Pedregal de San Ángel, México, D.F. Se discuten las diferencias encontradas en relación a los números cromosómicos y cariotipos de estas especies con los señalados en la literatura. Se apoya la evidencia de que las fusiones y fisiones Robertsonianas, los rearreglos estructurales, la poliploidía y la aneuploidía, han sido de notable interés para la especiación de los representantes de la familia Commelinaceae
Caracterización ficoflorística de los paredones de la Sierra de Juárez, Oaxaca. Importancia de las formas de crecimiento algales en la tipificación de un ambiente."
Authors: Tavera-Sierra Rosa Luz , González-González Jorge
Published: January 2019

En este estudio se muestra la importancia de integrar la fisiografía de un ambiente con la manifestación conspicua de las algas, a la que llamamos forma de crecimiento, para caracterizar dicho ambiente utilizando las formas de crecimiento que lo tipifican. Con este criterio se analizaron los paredones de la Sierra de Juárez encontrándose las siguientes formas de crecimiento: crecimientos hemisféricos compactos, flóculos filamentosos, flóculos mucilaginosos, películas compactas, películas filamentosas, tapetes y costras. Estas formas se describen en 15 muestras. 53.3% son de tipo floculoso y de ellas el 33.3% son flóculos filamentosos y el 20% son flóculos mucilaginosos. Las descripciones de la cobertura vegetal y de la fisiografía de paredones que hemos hecho para la Sierra de Juárez, son muy similares a las de otras latitudes, en las que predominan también los crecimientos floculosos, lo que nos permite definir un paredón como escurrimientos verticales con muy poca cantidad de agua en los que las formas de crecimiento típicas son los flóculos filamentosos y los flóculos mucilaginosos.
Anatomía del fruto de Casimiroa edulis (Rutaceae), "zapote blanco", durante su desarrollo
Authors: Zavaleta-Mancera Hilda Araceli , Engleman E. Mark
Published: January 2019

El zapote blanco es un fruto mexicano apreciado por su pulpa dulce comestible y por sus semillas medicinales. Tomando en cuenta la importancia de esta especie para México y la escasa información sobre la anatomía del fruto, se propuso estudiar el desarrollo del fruto desde antesis hasta madurez comestible. Se hicieron cortes y disociaciones. Se aplicaron tinciones generales con safranina y verde fijo, y particulares para almidón, lípidos, fenoles (taninos) y lignina. El crecimiento en diámetro del fruto presenta una curva simple sigmoide. La estructura fibrosa que cubre la semilla es un endocarpo que se origina de a) la epidermis interna pluriestratificada, b) estratos subepidérmicos de tejido fundamental y c) una red de tejido vascular que rodea el lóculo. Las paredes de este tejido se engruesan y lignifican poco antes de la madurez. El pericarpo no acumula almidón durante el desarrollo; en la madurez es dulce y con abundantes esferosomas (gotitas de lípidos); contiene numerosas glándulas de aceite de origen lisígeno, de formas y tamaños (0.1-5.0 mm) variables, cuyos ejes se disponen radialmente en el fruto. En el material estudiado no observamos la hipodermis externa descrita por Schroeder.
Mimosa bahamensis (Leguminosae) en la Península de Yucatán, México
Authors: Grether Rosaura , Camargo-Ricalde Sara L.
Published: January 2019

Este trabajo presenta la historia nomenclatural de Mimosa bahamensis Bentham, conocida comúnmente como "saskatzim" o "sak-katzim", el estudio de su fenología y de su distribución en la parte mexicana de la Península de Yucatán, como un elemento importante en áreas taladas de la selva, y en tintales y en vegetación de bajos. Se destaca su abundancia en terrenos de cultivo sujetos a quemas periódicas o abandonados y a la orilla de caminos y veredas. Se discute el carácter oportunista y típicamente secundario de esta especie, así como las posibles causas de su distribución disyunta.
Anatomía de la madera de cinco especies de Quintana Roo, México
Authors: Rebollar Silvia , De la Paz-Pérez Olvera Carmen , Quintanar Alejandra
Published: January 2019

Se presenta la descripción anatómica macroscópica y microscópica de la madera de 5 especies procedentes de Puerto Morelos, Quintana Roo: Drypetes lateriflora (Euphorbiaceae ), Exothea diphylla (Sapindaceae ), Myrcianthes fragrans var. fragrans (Myrtaceae ), Diospyros nicaraguensis (Ebenaceae) y Thevetia gaumeri (Apocynaceae). De cada especie se recolectó un árbol del cual se obtuvieron muestras de 15 X 7 X 1 cm con las que se hizo el estudio macroscópico y cubos de 2 x 2 cm de los que se obtuvieron .preparaciones fijas de cortes y material disociado para el estudio microscópico. A los elementos mensurables se les hizo un análisis estadístico y se consideró el valor de la media para su clasificación el cual se incluye junto con los valores mínimo y máximo de cada descripción. Se proporciona un mapa del lugar de recolección, un cuadro y fotografías de la estructura microscópica de las especies.
Perspectivas en el estudio de las Pteridofitas
Authors: Riba Ramón , Pérez-García Blanca
Published: January 2019

Las pteridofitas han sido estudiadas en sus inicios principalmente con base en la morfología del esporofito, en la que descansan las principales clasificaciones. Como resultado de los avances en otras disciplinas, y las mejoras tecnológicas en sistemas de observación y técnicas de laboratorio, en nuestros días hay una clara y evidente interrelación disciplinaria que ha llevado a revisar viejos conceptos con la consecuente modificación de ideas y teorías de la biología de las pteridofitas. En este artículo se pretende mostrar el desarrollo de la taxonomía, desde sus inicios hasta los diversos enfoques con que son abordados en la actualidad los problemas que plantea. Para ello se hará mención de las principales líneas de trabajo que se siguen, así como las contribuciones más importantes en cada campo de investigación.
Carlos Rafael Vázquez Yanes (1945-1999)
Authors: Novelo Eberto
Published: January 2019

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Editorial
Authors: Lira Rafael , Magaña Patricia
Published: January 2019

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Algunos aspectos biológicos de los hongos micorrícicos arbusculares (AMF)
Authors: Camargo-Ricalde Sara Lucía
Published: January 2019

El mecanismo ecológico por el cual la diversidad vegeta l (riqueza y composición de especies) es regulada y mantenida, todavía no se comprende en su totalidad; asimismo, se le ha dado muy poca atención a los efectos que producen las interacciones entre los microorganismos del suelo y las plantas. El objetivo de este trabajo es llevar a cabo una revisión de la literatura científica relacionada con algunos aspectos de la biología de los hongos micorrizógenos arbusculares (HMA) en relación con los mecanismos eco lógicos que afectan la diversidad vegetal. Varios estudios muestran que los HMA afectan a las plantas en su adecuación, crecimiento y abundancia relativos, y en su balance competitivo. Por lo tanto, los HMA son uno más de los factores que determinan la diversidad vegetal y la estructura de la comunidad. La discusión se centra en aspectos controvertibles de la investigación en HMA-diversidad vegetal.
Nueva especie del género Sicyos L. (Cucurbitaceae) para la República Mexicana
Authors: Rodríguez-Arévalo Isela , Lira Saade Rafael
Published: January 2019

Se describe y se ilustra una nueva especie del género Sicyos ( S. daviliae ) para los estados de Chiapas y Oaxaca en el sur de México. Esta nueva especie se distingue del resto de las especies mexicanas con frutos secos y espinosos del género, principalmente por la coloración de sus frutos, los cuales en fresco son verde hialinos y ocasionalmente maculados en color negro. Es similar a Sicyos wanningii Cogn . de Brasil y Argentina, de la cual difiere en varias características tales como la consistencia de la lámina, las ramificaciones de los zarcillos, la forma del estigma, y la coloración y tamaño de sus frutos.
In Memoriam: Roberto Cruz Cisneros (29 de abril de 1940-23 de abril de 2001)
Authors: Xelhuantzi-López Ma. Susana
Published: January 2019

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Diversidad florística del bosque mesófilo en el norte de Chiapas y su relación con México y Centroamérica
Authors: Ramírez-Marcial Neptalí
Published: January 2019

Se registró la distribución de familias y géneros de árboles y arbustos en las montañas del norte de Chiapas y se comparó con otras 23 localidades de bosque mesófilo de montaña en México, Guatemala y Costa Rica. De un total de 99 familias, las más representadas por géneros fueron Rubiaceae ( 19), Leguminosae (16), Ericaceae (15) y Compositae ( 14). Los géneros Quercus, Clelhra, Cornus, Oreopanax y Ceslrum fueron citados en más de 95% de los sitios; 32 géneros (10%) sólo se registraron una vez. Mediante un análisis no métrico de escala multidimensional, se reconocieron seis áreas de distribución actual de acuerdo con sus valores de diversidad y posición geográfica. La mayor riqueza genérica se registró para Manantlán, El Triunfo, Sierra de Talamanca y las Montañas del norte de Chiapas. La mayor proporción de los géneros ( 41 % ) tiene una distribución meridional, 15% holártica, 4% americano-africana, 9% malayo-americana, 3% austral-antártica, 14% pantropical, 5% de amplia distribución y 9% de los géneros se consideran exclusivos de México y/o Centroamérica.
Editorial
Authors: Sosa Victoria , Meave Jorge A.
Published: January 2019

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Efecto del fuego en la estructura poblacional y la regeneración de dos especies de encinos (Quercus liebmanii Oerst. y Quercus magnoliifolia Née) en la región de La Montaña (Guerrero), México
Authors: Peña-Ramírez Víctor M. , Bonfíl Consuelo
Published: January 2019

This study analyzed the effect of superficial fires on population structure and individual crown area of two tree species: Quercus liebmanii and Q. magnoliifolia, in San José Lagunas, Guerrero, southern Mexico. For each species two sites were selected, in which ca. 350 individuals were recorded per species. Individuals were classified in four size categories. During the study period (1993-95), superficial fires occurred at all four sites. As a result, the relative frequency of the smallest plants increased due to height reductions among juveniles, while there were no changes in adult tree frequency. Analysis of changes in crown cover showed that seedlings and adult trees recovered from fire, while there were reductions in crown cover in the juvenile categories. It is concluded that although both species tolerate fires, the high frequency fire regimen prevailing in the study area may inhibit the regeneration of their populations.
Validation of the name Zamia elegantissima Schutzaman, Vovides et Adams
Authors: Schutzman Bart , Vovides Andrew P. , Adam Russell S.
Published: January 2019

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El uso ceremonial de la cícada amenazada "espadaña" ( Dioon merolae , Zamiaceae) por una comunidad de la depresión central de Chiapas, México
Authors: Pérez-Farrera Miguel A. , Vovides Andrew P.
Published: January 2019

Dioon merolae De Luca, Sabato et Vázq.Torres, una especie de cícada de Chiapas conocida localmente como espadaña, juega un papel importante durante la festividad de la Santa Cruz del 3 de mayo entre la comunidad de Suchiapa de la Depresión Central del estado de Chiapas. Aparentemente ésta es una tradición nativa chiapaneca de origen prehispánico que se sincretizó con la religión católica durante la época colonial. Sus hojas se usan para adornar altares cada mayo durante esta festividad religiosa Católica. Las cícadas no parecen sufrir daño alguno por la poda anual de las hojas, pero la amenaza actual a las poblaciones y a esta tradición milenaria viene de activistas de otras tradiciones religiosas que provocan incendios al hábitat de la cícada durante el período del estiaje antes de la cosecha de las hojas.
Herbivory damage on oak seedlings at the edge of cloud forest fragments
Authors: Reynoso Juan Antonio , Williams-Linera Guadalupe
Published: January 2019

Herbivory damage on Quercus xalapensis Humb. et Bonpl. seedlings was experimentally determined in two cloud forest fragments (Veracruz, Mexico), one with an abrupt edge (forest contiguous to a one-year old stand), and another with a soft edge (forest contiguous to a 10 year-old stand). Sets of seedlings were planted in transects parallel to the border. The experiments were conducted in the warm-dry (April-May) and warm-wet (July-August) seasons. Herbivory damage was measured at the beginning and at the end of each season. Weekly, microclimatic variables were measured in the same positions in which seedlings were planted. During the wet season, herbivory was similar at different distances from the border (ca. 2%), but during the dry season, herbivory was higher at the forest border (2.75-11.75%) than at the old-field (0.50-0.75%). Herbivory and air temperature were higher, and air humidity and soil water content were lower in the abrupt than in the soft edge. Our results suggest that herbivory levels on oak seedlings depend on modulating factors such as the edge type and the season of the year.
Caracterización ecológica y diversidad de los bosques de encino de la sierra de Zapalinamé, Coahuila, México
Authors: Encina-Domínguez Juan A. , Zárate-Lupercio Alejandro , Valdés-Reyna Jesús , Villarreal-Quintanilla José A.
Published: January 2019

La sierra de Zapalinamé es un área natural protegida del sureste de Coahuila, en la transición entre el Desierto Chihuahuense y la Sierra Madre Oriental. En sus cañones, donde el clima es templado subhúmedo y templado semiseco, se desarrollan bosques de encino. Con la finalidad de conocer la distribución, la riqueza y la diversidad de especies de estos bosques, se establecieron 66 sitios circulares de 500 m2, donde se tomó información de la densidad, el diámetro y la cobertura de las plantas leñosas, y de la frecuencia de las hierbas. Se utilizó la densidad de plantas leñosas y la frecuencia de todos los gremios de plantas para calcular el índice de diversidad de Shannon-Wiener; la relación entre la diversidad y la riqueza de especies leñosas con las variables ambientales se analizó mediante regresión lineal. Se reconocieron dos asociaciones del encinar: bosque de Quercus greggii-Q. mexicana y bosque de Q. saltillensis-Q. laeta, ambos distribuidos en un intervalo altitudinal de 2,000 a 2,600 m. La precipitación media es de 324 mm y la temperatura media es de 16ºC. Los bosques de Q. saltillensis–Q. laeta presentan el índice de diversidad más alto, así como la mayor riqueza de hierbas y arbustos, debido a las condiciones ambientales particulares, a la mayor incidencia de disturbios antropogénicos y a la infiltración de especies provenientes del matorral submontano. El patrón de diversidad de especies y su relación con los gradientes ambientales muestra que la diversidad y la riqueza disminuyen con el aumento de altitud y de precipitación, pero que aumentan con el incremento de la temperatura. En estos encinares la riqueza de especies varía marcadamente, siendo las hierbas las de mayor riqueza, seguidas por los arbustos y al final los árboles. La  diversidad alfa promedio para las parcelas de muestreo fue de 40 especies. El patrón en la diversidad parece resultar de una combinación de procesos ecológicos con la configuración espacial y el historial de manejo del área protegida. En el diseño de estrategias de conservación biológica se deberá considerar el control de los disturbios antropogénicos.
Etnobotánica y ecología de plantas utilizadas por tres curanderos contra la mordedura de serpiente en la región de Acayucan, Veracruz, México
Authors: Ramos-Hernández Mario , Ávila-Bello Carlos H. , Morales-Mávil Jorge E.
Published: January 2019

Se estudió el conocimiento etnobotánico y se analizaron aspectos ecológicos de plantas utilizadas como antiviperino por tres curanderos de la región de Acayucan, Veracruz, México. Los objetivos fueron conocer las plantas usadas para la elaboración del suero y evaluar la estructura general de la vegetación en dos áreas en donde se recolectan estas plantas. Se llevaron a cabo  entrevistas y recorridos de campo con los tres curanderos, se calcularon las frecuencias relativas de las especies y se registró su forma de uso. La estructura de la vegetación se estudió en sitios de 400 m2 divididos en parcelas de 25 m2. Se determinaron 16 especies usadas contra la mordedura de serpiente. Las plantas se preparan de tres formas: cocimiento, pulverización y extracto alcohólico; todos los métodos se aplican vía oral. Las zonas de recolección son áreas muy aisladas y fragmentadas, rodeadas por terrenos utilizados para la agricultura y la ganadería.
Notas sobre la flora de la Península de Yucatán VII: Boehmeria cylindrica (Urticaceae), un nuevo registro para la región
Authors: Tapia José Luis , Carnevalli-Fernández-Concha Germán , Duno-de Stefano Rodrigo , Ramírez-Morillo Ivón M. , Hernández-Aguilar Silvia , Can-Itza Lilia Lorena
Published: January 2019

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Before data acquisition -- Start MRI Project Spinoza REC v12
Authors: Beemsterboer Tinka , Snoek Lukas , Scholte H.steven
Published: January 2019

Dear researcher, This protocoloutlines the steps to start an MRI project at the Spinoza Centre Roeterseiland (REC). If you haven't had contact with Steven Scholte or Tinka Beemsterboer, make sure to contact them before completing this protocol. You can reach us by email: Steven Scholte: h.s.scholte@uva.nl Tinka Beemsterboer: t.beemsterboer@uva.nl If you have any suggestions for improving the workflow, don't hesitate to add comments to the steps in the protocol. Hope to see you soon! The Spinoza REC team, Steven Scholte, Tinka Beemsterboer, and Lukas Snoek
Preparation of paclitaxel and vitamin D3-loaded PLGA nanoparticles v2
Authors: Jafari Alireza , Madani Fateme , Khodaverdi Sepideh , Soltani Bahram , Skandari Vajihe
Published: January 2019

Nano-precipitation method was used to prepare the PLGA-PTX-VITD co-delivery NPs. The PVA polymer was dissolved in deionized water, as an aqueous phase, under continuous magnetic stirring at 70 °C for 5 h to obtain a homogenous solution; likewise, 50 mg of the PLGA and 5 mg of the PTX were dissolved in 10 ml and 5 ml of acetone respectively. Next, 1 ml of the vitamin D3 was added to acetone (0.1% W/V). Subsequently, the PTX was poured in the PLGA solution. Afterward, organic phase was poured in the PVA (100 ml) and stirred overnight at the room temperature. After the evaporation of the organic phase, the NPs were collected by centrifugation (Eppendorf, U.S.A) at 12000 rpm for 30 min at 4°C and washed twice with deionized water[17].
Towards a More Nuance Understanding of White Teachers of English Learners: Increasing Capacity and Capabilities
Authors: Shim Jenna Min
Published: January 2019

Predicated on the idea that race, racialization, and racism are major factors that shape language teaching and learning, this paper draws on the second wave White teacher identity studies to argue for a more nuanced understandings on White monolingual teachers’ racial identities by exploring their perspectives on English learners’ (ELs’) learning experiences by asking the following research questions: (1) From the EL teachers’ perspectives, what contribute to EL’s struggles in school? (2) What effects do the EL teachers’ perspective have on ELs’ school experiences? (3) Are there any consistencies or inconsistencies among the participants’ perspectives and what do they mean? The findings report that tensions and contradictions arising from inconsistencies across the participants’ perspectives as well as within each teacher’s perspective reflect co-existence of race evasive and race conscious identities that in turn can serve as an important locus to transform their perspectives toward more equitable pedagogical practices for ELs.
Perceptions about Self-recording Videos to Develop EFL Speaking Skills in Two Ecuadorian Universities
Authors: Encalada Maria Asuncion Rojas , Sarmiento Sonia Magali Arteaga
Published: January 2019

The present study explores the perceptions of EFL students from two Ecuadorian universities on the use of Self-Recording Videos (SRV) to develop speaking skills.  As students do not have the opportunity to talk in the target language outside their classes, the authors of the present study analyzed the participants’ viewpoints regarding SRV to improve their conversational abilities.  There is still limited research on the use of SRV for English speaking practice in a foreign country, so the researchers' purpose is to fill this gap in the literature to contribute to further studies on the topic.  The authors consider essential to acknowledge the positive aspects of using this technique from the learners’ perspectives.  For this purpose, participants were required to self-record a video related to the content of the class during the week and submit it to the Moodle platform.
A Case Study of Communication Difficulties between a Chinese Advanced Learner and Native Speakers
Authors: Jin Xiaoling
Published: January 2019

The paper focuses on the communication difficulties between a Chinese advanced learner and native speakers. The research is carried out through a case study approach and is grounded on the data collected from recording conversations between a Chinese participant and two native speakers. The recorded conversations are spontaneous, covering general topics encountered in real life. Three linguistic findings are: first, grammar does not usually affect advanced learners in speaking whereas the lack of appropriate vocabulary may be a bigger challenge; second, advanced learners could learn contents words and expressions without instruction but through a rich target language input; third, incorrect pronunciation can be corrected through consistent physical practice and corrective feedback. Also, the research shows that foreign language anxiety, cultural differences and L1 influence play important roles in communication with native speakers. As to the study strategy, this research emphasizes the importance of continuous language exposure for advanced learners. This case study could be applied by students and teachers in EFL classrooms and will also contribute to the study of Chinese English.
The Relationship between Morphological Awareness and Vocabulary Knowledge of Thai EFL Students
Authors: Tarat Sarunya
Published: January 2019

This study focuses on the relationship between morphological awareness and vocabulary knowledge of English among Thai EFL university students. All participants are taking English language as their major field in the universities situated at the lower northern region of Thailand. The morphological awareness identification test was employed to identify the linkage between morphological awareness and vocabulary gain Thai EFL learners. The test was divided into 2 parts: self-checking and morpheme identification. Fifty English vocabularies in intermediate and upper-intermediate level were used in the test in which the participants were requested to check whether they have seen the vocabularies in the test and also asked to break those vocabularies into morphemic units. The results showed that the participants possessed an adequate level of morphological awareness to break words into morphemes correctly even though they were unknown words of the participants. Additionally, the findings also revealed that there is no significant difference between male and female in acquiring morphological awareness of English and gaining English vocabularies.
Position-Force Control for a Six Coordinate Industrial Robot when Performing Complicated Surface Treatment
Authors: Afonin V. L. , Gavrilina L. V. , Smolentsev A. N.
Published: January 2019

When performing certain technological operations, multi-coordinate industrial robots require simultaneous control of the movement of the executive body and the developed effort. When performing assembly operations (for example, a shaft with a bush), it is necessary to perform a free movement of the shaft along the bore of the bushing and to ensure minimum pressure on the bore walls. When performing operations to handle complex surfaces of parts, it is simultaneously required to move the tool over the surface at a specified speed and to perform a metered pressure on the surface. Since it is impossible to control the force and motion simultaneously at the same coordinate, it is necessary either to switch from one control method to another, or to control various actuators and different controllable coordinates of the actuator. In multi-coordinate robots, this task is complicated by the fact that to control the movement of one of the Cartesian coordinates of the executive body, and by another force, it is simultaneously necessary to control the interrelated generalized coordinates of the robot’s mechanism. In the work presented, the solution of the problem of control of a six-coordinate industrial robot is described, in which the separation of the degrees of mobility into power control and positional control of trajectory motion is carried out. In order to accomplish the task, additional variable parameters are introduced for the treatment of complex surfaces, which determine the position of the cutting edge on the cutting surface, which makes it possible to expand the service area of the robot during selection, for example, one of the coordinates for controlling the pressure force. This task is considered using the example of a six-coordinate industrial robot when performing a complex surface treatment operation, when it is required to program the tool at a specified speed along a path on the surface and at the same time carry out the controlled pressure of the tool on the surface.