Assessing the Impact of Computer Programming in Understanding Limits and Derivatives in a Secondary Mathematics Classroom

This study explored the development of student’s conceptual understanding of limit and derivative when specific computational tools were utilized. Fourteen students from a secondary Advanced Placement Calculus AB course explored the limit and derivative concepts from calculus using computational tools in the Maple computer algebra system. Students worked in pairs utilizing the pair-programming collaborative model. Four groups of student pairs constructed computational tools and used them to explore the limit and derivative concepts. The remaining four student pairs were provided similar tools and asked to perform identical explorations. A multiple embedded case design was utilized to explore ways students in two classes, a programming class P and a non-programming class N, constructed understandings focusing upon their interactions with each other and with the computational tools. The Action-Process-Object-Schema (APOS) conceptual model and Constructionist framework guided design and construction of the tools, outlined developmental goals and milestones, and provided interpretive context for analysis. Results provided insights into the effective design and use of computational tools in fostering conceptual understanding. The study found the additional burden of programming redirected students’ attention away from the intended conceptual understandings. The study additionally found, however, that pre-constructed tools effectively promote conceptual understanding of the limit concept when coupled with a mature conceptual model of development. Four themes influencing development of these understandings emerged: An instructional focus on skills over concepts, the instructional sequence, the willingness and ability of students to adopt and utilize computational tools, and the ways cognitive conflict was mediated

Web Application for Evaluation and Tracking of the University Subjects and Graduates

[Summary] The adaptation of the university studies to the current European Higher Education Area (EHEA) requires the set up of mechanisms, which allow performance evaluation of the subjects compounding the new university studies. Thus, universities create new positions as “graduate quality manager” with the objective of introducing the continuous improvement of the learning process. It is also needed to provide the working tools demanded by the new manager positions. The main objective of the project presented in this paper is the design and the implementation of a web application which allows not only carrying out the typical student evaluation tasks, but introducing customizable performance rates which are dynamically evaluated. The customization of the performance rates depends on both subjects and exams. Finally, the application is able to compute the graduate performance rates from the rates defined for the subjects.[Resumen] La adaptación de las titulaciones universitarias actuales al Espacio Europeo de Educación Superior (EEES) requiere la puesta en marcha de mecanismos de evaluación del rendimiento de las asignaturas que componen las nuevas titulaciones. Así, las universidades empiezan a crear nuevas figuras como “responsable de calidad de la titulación”, con el objetivo de introducir el concepto de mejora continua del proceso formativo. Es por tanto necesario proporcionar nuevas herramientas de trabajo a estas figuras. El objetivo principal del proyecto que se presenta en este artículo es el diseño e implementación de una aplicación web que permita no sólo llevar a cabo las tareas convencionales de evaluación del alumnado, sino también introducir índices de rendimiento personalizables por cada asignatura y convocatoria y su evaluación dinámica. Finalmente, la aplicación permite calcular los índices de rendimiento de la titulación a partir de los índices definidos para las asignaturas

Coupled Interannual Variability of Wind and Sea Surface Temperature in the Caribbean Sea and the Gulf of Mexico

This work describes dominant patterns of coupled interannual variability of the 10-m wind and sea surface temperature in the Caribbean Sea and the Gulf of Mexico (CS&GM) during the period 1982-2016. Using a canonical correlation analysis (CCA) between the monthly mean anomalies of these fields, four coupled variability modes are identified: the dipole (March-April), transition (May-June), interocean (July-October), and meridional-wind (November-February) modes. Results show that El Nino-Southern Oscillation (ENSO) influences almost all the CS&GM coupled modes, except the transition mode, and that the North Atlantic Oscillation (NAO) in February has a strong negative correlation with the dipole and transition modes. The antisymmetric relationships found between the dipole mode and the NAO and ENSO indices confirm previous evidence about the competing remote forcings of both teleconnection patterns on the tropical North Atlantic variability. Precipitation in the CS and adjacent oceanic and land areas is sensitive to the wind-SST coupled variability modes from June to October. These modes seem to be strongly related to the interannual variability of the midsummer drought and the meridional migration of the intertropical convergence zone in the eastern Pacific. These findings may eventually lead to improving seasonal predictability in the CS&GM and surrounding land areas.Programa Nacional de Posgrados de Calidad of the Consejo Nacional de Ciencia y Tecnologia of Mexico; CONACYT-SENER-Hidrocarburos Project [201441]6 month embargo; published online: 20 June 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

δ13C and δ15N in the endangered Kemp’s ridley sea turtle Lepidochelys kempii after the Deepwater Horizon oil spill

The Deepwater Horizon explosion in April 2010 and subsequent oil spill released 3.19 × 106 barrels (5.07 × 108 l) of MC252 crude oil into important foraging areas of the endangered Kemp’s ridley sea turtle Lepidochelys kempii (Lk) in the northern Gulf of Mexico (GoM). We measured δ13C and δ15N in scute biopsy samples from 33 Lk nesting in Texas during the period 2010 to 2012. Of these, 27 were equipped with satellite transmitters and were tracked to traditional foraging areas in the northern GoM after the spill. Differences in δ13C between the oldest and newest scute layers from 2010 nesters were not significant, but δ13C in the newest layers from 2011 and 2012 nesters was significantly lower compared to 2010. δ15N differences were not statis- tically significant. Collectively, the stable isotope and tracking data indicate that the lower δ13C values reflect the incorporation of oil rather than changes in diet or foraging area. Discriminant analysis indicated that 51.5% of the turtles sampled had isotope signatures indicating oil exposure. Growth of the Lk population slowed in the years following the spill. The involvement of oil exposure in recent population trends is unknown, but long-term effects may not be evident for many years. Our results indicate that C isotope signatures in scutes may be useful biomarkers of sea turtle exposure to oil

Desarrollo de una metodología de crianza en laboratorio del gusano cogollero del maíz Spodoptera frugiperda (Smith) como hospedante de insectos biocontroladores de interés agrícola.

Proyecto de Investigación Instituto Tecnológico de Costa Rica. Escuela de Biología. Centro de Investigación en Biotecnología (CIB), 2008Con el fin de desarrollar una metodología de crianza en laboratorio que permita la producción masiva de organismos biocontroladores de Spodoptera frugiperda, se colectaron ejemplares en estado larval en cultivares de maíz en fase vegetativa en diferentes localidades de Costa Rica. Para ello se utilizaron jaulas plásticas de recolección a las que previamente se les había colocado hojas tiernas de maíz que evitaran la muerte de las larvas y que permitiera ser transportadas hasta el Laboratorio de Biocontroladores del CIB-ITCR, Cartago. Al llegar se individualizaron en microjaulas de plástico ámbar para evitar la muerte de los individuos por canibalismo. Al inicio del ensayo las larvas fueron alimentadas con hojas tiernas de maíz por espacio de dos meses. Luego se evaluó la dieta artificial BIO-MIX H-89 modificada para el desarrollo de huevo hasta pupa y durante la fase de adulto, se utilizó una solución de miel de abeja al 10% (v/v) como fuente de alimento. Se aplicó un ANOVA para medir las diferencias significativas entre cada etapa del ciclo de vida con ambas dietas, donde se encontró que al implementar la dieta artificial se redujo el ciclo de vida de esta especie a (45,10±1,20) días, y se prolongó el periodo larval a (26,80±1,41) días; sin embargo, en la primera elaboración de ésta se presentaron problemas por la aparición de hongos saprófitos, por lo que fue necesario adicionar cuatro preservantes al medio. Se identificó el hongo entomopatógeno Beauveria bassiana como controlador biológico de esta especie sobre larvas producidas en dieta natural. Finalmente, el uso de la dieta artificial fue la más efectiva para criar esta especie en laboratorio porque al reducir el ciclo de vida y ampliar la duración del estadio larval se convierte la especie como hospedante potencial para la producción biotecnológica de organismos biocontroladores de interés agrícola en laboratorio. ____________________________________________________________________________ Abstract To establish a methodology to breed in laboratory the massive production of bio-controllers organisms for Spodoptera frugiperda (Smith), some specimens in their larval stage were collected in corn plantations in vegetative phase in different places of Costa Rica. For it, the larvas were brought to the lab in collecting cages in which previously were placed corn leaves to avoid the death of the larvas and transport them to the Biocontrollers Lab of the CIB – ITCR, Cartago. At the arriving they were individualized in small, amber micro cages to avoid cannibalism between larvas, at the beginning of the test the larvas were feed with corn leaves during two months. After that, the artificial diet BIO-MIX H-89 modified were used to feed the insects for the develop of them since egg to pupae phase. During its adult phase butterflies were feed with honey 10% (v/v). An ANOVA analysis was applied to measure significant differences between its life cycle applying each diet, the results show that with artificial diet the life cycle gets shorter to (45,10±1,20) days and the larval state gets longer to (26,80±1,41) days; nevertheless, the first production of this one showed the presence of mushrooms, because of that, the addition of four preservative agents were necessary. The entomopathogenic mushroom Beauveria bassiana was identified as a biological controller for this specie over larvas produced using natural diet. Finally, the use of the artificial diet was more effective for breed this specie in laboratory because of the reduction of the life cycle and because of the extension of the larval stage thatCentro de Investigación en Biotecnologí

The Relationship of the North American Monsoon to Tropical and North Pacific Sea Surface Temperatures as Revealed by Observational Analyses

The North American monsoon is a seasonal shift of upper- and low-level pressure and wind patterns that brings summertime moisture into the southwest United States and ends the late spring wet period in the Great Plains. The interannual variability of the North American monsoon is examined using the NCEP–NCAR reanalysis (1948–98). The diurnal and seasonal evolution of 500-mb geopotential height, integrated moisture flux, and integrated moisture flux convergence are constructed using a 5-day running mean for the months May through September. All of the years are used to calculate an average daily Z score that removes the diurnal, seasonal, and intraseasonal variability. The 30-day average Z score centered about the date is correlated with Pacific sea surface temperature anomaly (SSTA) indices associated with the El Niño–Southern Oscillation (ENSO) and the North Pacific oscillation (NPO). These indices are Niño-3, a North Pacific index, and a Pacific index that combines the previous two. Regional time-evolving precipitation indices for the Southwest and Great Plains, which consider the total number of wet or dry stations in a region, are also correlated with the SSTA indices. The use of nonnormally distributed point source precipitation data is avoided. Teleconnections are computed relative to the climatological evolution of the North American monsoon, rather than to calendar months, thus more accurately accounting for the climatological changes in the large-scal

Relationship of the North American Monsoon to tropical and North Pacific sea surface temperatures as revealed by observational analyses, The

Includes bibliographical references (pages 43-48).April 2000.The North American Monsoon is a seasonal shift of upper and low level pressure and wind patterns which brings summertime moisture into the Southwest United States and ends the late spring wet period in the Great Plains. The climatology and interannual variability of the North American Monsoon are examined using the NCEP/NCAR Reanalysis (1948-98). The diurnal and seasonal evolution of 500-mb geopotential height, integrated moisture flux, and integrated moisture flux convergence are constructed using a five-day running mean for the months May through September. All of the years are used to calculate an average daily Z-score which removes the diurnal, seasonal, and intraseasonal variability. The average Z-score centered about the date is correlated with three Pacific SST indices associated with the El Niño Southern Oscillation (ENSO) and the North Pacific Oscillation (NPO). These indices are: Niño 3, a North Pacific index, and a North American Monsoon index (M) which combines the previous two. Regional time evolving precipitation indices for the Southwest and Great Plains, which consider the total number of wet or dry stations in a region, are also correlated with the SST indices. The new reanalysis climatology reveals: the time of maximum northward extent of the monsoon is late July, a diurnal cycle in atmospheric moisture which reflects the evolution of summer thunderstorms, the presence of the Baja and Great Plains low level jets, and the seasonal dependence of atmospheric moisture on monsoon ridge position. These results are in agreement with previous, more comprehensive reanalysis climatologies using shorter lengths of record. Pacific SSTs are related to a sequence of teleconnection patterns over North America through the summer. The relationship to the atmospheric circulation is strongest at monsoon onset, when the Pacific Transition pattern controls the large-scale distribution of moisture across the western U.S. A high (low) NPO phase and El Niño (La Nina) conditions favor a trough (ridge) over the northern Rocky Mountains, northern Great Plains. In the Great Plains the spring wet season is lengthened (shortened) and early summer rainfall and integrated moisture flux convergence are above (below) average. In the Southwest monsoon onset is late (early) and early summer rainfall and integrated moisture flux convergence are below (above) average. Relationships with the Pacific SST indices decay in the later part of the monsoon. These idealized climatological responses associated with high and low values of the M index were observed in the Midwest Flood of 1993 and the Drought of 1988, respectively. Tropical and North Pacific SSTs are related to atmospheric moisture and precipitation in the western U.S. to varying degrees depending on location. In the Great Plains, North Pacific SSTs are dominant factor, while in the Southwest tropical and North Pacific SSTs are equally important. Though the M index is the better diagnostic for North American Monsoon, only the time-coincident relationships with atmospheric circulation and moisture are statistically significant. A statistically significant relationship exists between spring Niño- 3 and the atmospheric circulation pattern over North America at monsoon onset