SISTEMAS DE EJERCICIOS PARA LA ENSEÑANZA DE LA ASIGNATURA MATEMÁTICA I, EN LA CARRERA DE CONTABILIDAD Y FINANZAS

La carrera Contabilidad y Finanzas se estudia en la Universidad de Ciego de Ávila, se caracteriza por tener un ingreso de alumnos de altos índices académicos, sin embargo sus resultados docentes en las diferentes asignaturas de Matemática del currículo, en particular Matemática I, no constituyen un reflejo de esta situación. Por estas razones el presente trabajo toma como punto de partida, la problemática existente en relación con el bajo rendimiento de los estudiantes en la asignatura Matemática I de esta carrera. En la búsqueda de las causas se encontró que en el desarrollo del proceso docente educativo de esta asignatura se han detectado dificultades al tratar contenidos que requieren de conocimientos de la Enseñanza Media General, además no se han previsto estrategias que logren mejorar esta situación. El sistema de ejercicios propuestos se centró en preparatorios, integradores y de profundización. Con esta propuesta metodológica se contribuyó a lograr que los estudiantes transiten adecuadamente, por los procesos de motivación, comprensión y sistematización, lográndose de esta forma la apropiación de los nuevos contenidos en interrelación con los precedente

PERSPECTIVA METODOLÓGICA PARA EL DESARROLLO DE LA HABILIDAD CALCULAR DERIVADAS EN LA FORMACIÓN DEL INGENIERO CIVIL

En el plan de estudios D para la formación del Ingeniero Civil se destaca el desarrollo de habilidades en diferentes vertientes que le permitan al estudiante enfrentarse con éxito a su futura vida laboral. De forma precisa en el programa de la Disciplina Matemática Aplicada aparece como uno de los objetivos generales desarrollar habilidades para el cálculo, la comunicación y la comprensión de propiedades y características matemáticas de magnitudes y formas  en las variantes formal, gráfica, numérica y verbal”. En el presente trabajo se realizó el estudio de una de las habilidades matemáticas fundamentales: calcular, determinando aquellos elementos que inciden en su desarrollo, las dificultades que se presentan y proponiendo una alternativa de solución desde una perspectiva metodológica

Editing and reading early modern mathematical texts in the digital age

The advent of digital technology has brought a world of new possibilities for editors of historical texts. Though much has been written about conventions for digital editing, relatively little attention has been paid to the particular question of how best to deal with texts with heavily mathematical content. This essay outlines some ways of encoding mathematics in digital form, and then discusses three recent digital editions of collections of early modern mathematical manuscripts

Assembly of high nuclearity clusters from a family of tripodal tris-carboxylate ligands

A family of four tris-carboxylic acid ligands 1,3,5-tris(4′-carboxybiphenyl-2-yl)benzene (H3L1), 1,3,5-tris-2-carboxyphenylbenzene (H3L2), 1,3,5-tris(4″-carboxy-para-terphenyl-2-yl)benzene (H3L3) and 1,3,5-tris(3′-carboxybiphenyl-2-yl)benzene (H3L4) have been synthesised and reacted with first row transition metal cations to give nine complexes which have been structurally characterised by X-ray crystallography. The ligands share a common design motif having three arms connected to a benzene core via three ortho-disubstituted phenyl linkers. The ligands vary in length and direction of the carboxylic acid functionalised arms and are all able to adopt tripodal conformations in which the three arms are directed facially. The structures of [Zn8(μ4-O)(L1)4(HCO2)2(H2O)0.33(DMF)2] (1a-Zn), [Co14(L2)6((μ3-OH)8(HCO2)2(DMF)4(H2O)6] (2-Co), [Ni14(L2)6(μ3-OH)8(HCO2)2(DMF)4(H2O)6] (2-Ni), [Zn8(μ4-O)(L3)4(DMF)(H2O)4(NO3)2] (3-Zn), [Ni5(μ-OH)4(L2)2(H2O)6(DMF)4] (5-Ni), [Co8(μ4-O)4(L4)4(DMF)3(H2O)] (6-Co) and Fe3(μ3-O)(L4)2(H2O)(DMF)2)] (7-Fe) contain polynuclear clusters surrounded by ligands (L1–4)3− in tripodal conformations. The structure of [Zn2(HL1)2(DMF)4] (1b-Zn) shows it to be a binuclear complex in which the two ligands (HL2)2− are partially deprotonated whilst {[Zn3(L2)2(DMF)(H2O)(C5H5N)]·6(DMF)}n (4-Zn) is a 2D coordination network containing {Zn2(RCO2)4(solv)2} paddlewheel units. The conformations of the ligand arms in the complexes have been analysed, confirming that the shared ortho-disubstituted phenyl ring motif is a powerful and versatile tool for designing ligands able to form high-nuclearity coordination clusters when reacted with transition metal cations

Settling into an Increasingly Hostile World: The Rapidly Closing “Recruitment Window” for Corals

Free space is necessary for larval recruitment in all marine benthic communities. Settling corals, with limited energy to invest in competitive interactions, are particularly vulnerable during settlement into well-developed coral reef communities. This situation may be exacerbated for corals settling into coral-depauperate reefs where succession in nursery microhabitats moves rapidly toward heterotrophic organisms inhospitable to settling corals. To study effects of benthic organisms (at millimeter to centimeter scales) on newly settled corals and their survivorship we deployed terra-cotta coral settlement plates at 10 m depth on the Mesoamerican Barrier Reef in Belize and monitored them for 38 mo. During the second and third years, annual recruitment rates declined by over 50% from the previous year. Invertebrate crusts (primarily sponges) were absent at the start of the experiment but increased in abundance annually from 39, 60, to 73% of the plate undersides by year three. Subsequently, substrates hospitable to coral recruitment, including crustose coralline algae, biofilmed terra-cotta and polychaete tubes, declined. With succession, substrates upon which spat settled shifted toward organisms inimical to survivorship. Over 50% of spat mortality was due to overgrowth by sponges alone. This result suggests that when a disturbance creates primary substrate a “recruitment window” for settling corals exists from approximately 9 to 14 mo following the disturbance. During the window, early-succession, facilitating species are most abundant. The window closes as organisms hostile to coral settlement and survivorship overgrow nursery microhabitats