Miguel Alcaraz-Rivera

Feedback is central to formative e-assessment. How long students spend on it may itself be associated with whether they correct an error on a second attempt. This study examined the association between feedback-screen time (FST) and second-attempt accuracy (SAA) in mathematics, and whether it varies across items. We analyzed 8051 interactions from 1654 students following an incorrect first attempt on eight differential calculus items in the MathUP e-assessment platform. A generalized estimating equation, clustered by student, modeled SAA as a function of FST (a piecewise linear spline selected through a pre-registered, cross-validated protocol), feedback type (diagnostic plus worked-example vs. worked-example alone), and item identity. Predicted SAA rose steeply up to approximately 3.4 s of FST (61.0%) and changed little thereafter (69.1% at 640 s). Neither the FST × item nor the feedback type × item interaction improved out-of-sample performance. Item identity was associated with SAA. Feedback type showed only a marginal association, based on 143 self-selected worked-example-only interactions. Within one course and one institution, SAA was associated with FST mainly over the first few seconds. These observational findings do not establish causality and warrant replication in other contexts.

This article focuses on solving the order quantity allocation problem for retailers. It considers factors such as quality constraints, nonlinear quantity discounts, and price-dependent demand. By formulating it as a nonlinear maximization problem, the article aims to find the best combination of suppliers and order quantity out of infinite solutions to maximize the retailer’s profit. The main contribution of this research is a new mathematical model that can solve the problem of quality constraint and demand in a single step. This problem is complex due to the number of equations, their nonlinear nature, and the various trade-offs given by the market. Additionally, this research considers demand as output and includes price-dependent demand, which is more realistic for retailers. The proposed model was tested using an example from the recent literature and showed better results than the previously published best solution regarding profit maximization.

Alumnos de primer ingreso a la universidad cometen errores algebraicos cuya fuente, probablemente, es un uso incorrecto o inadecuado de las variables. Es de interés para la Educación Matemática contar con un instrumento que permita identificar cuáles son los usos y caracterizaciones de la variable que presentan mayor dificultad. El objetivo de este trabajo es la adaptación y validación de un instrumento que cumpla con estas características. Las preguntas del instrumento son un conjunto representativo de la complejidad del objeto matemático variable con los tres significados parciales: variable como incógnita, variable como número general y variable en relación funcional. Las caracterizaciones abordan niveles de abstracción que van desde la interpretación a la manipulación y simbolización. Para la validación del cuestionario, éste se aplica a 251 alumnos de las carreras administrativas de una universidad privada en Guadalajara, México. Aquellos ítems con bajas comunalidades y que en un análisis factorial muestran, ya sea factores inestables o una distribución en factores múltiples se descartan, generando un cuestionario reducido que se aplica a 129 alumnos. La confiabilidad del nuevo cuestionario es buena con un alfa de Cronbach de 0.808. Se comprueba su validez con once factores relativos a las distintas caracterizaciones de los tres usos de la variable, que explican el 75.68% de la varianza total.

Currently, the Mexican avocado supply chain has some social limitations that make the traceability process a difficult task and severely limits the regions that can add their harvest to the international market. We hypothesize that modernizing the traceability process and improving the trust of the final user could help in opening the market to other regions. This paper describes the Mexican avocado supply chain characteristics, identifies the actors involved in the supply chain, and emphasizes the problems that the current actors have when exporting them to the US market. On this basis, we propose a technological solution system to automate the traceability process. The system was designed to comply with the authority and consumer requirements. It proposes a combination of the benefits of traditional data traceability using Microservices architecture with a new layer of Blockchain auditing that will add value to current and new actors in every step of the supply chain. We contribute by proposing a model that adds value to the avocado supply chain with the following characteristics: Integrity, auditing service, dual traceability, transparency, and a front-end application with trust user-oriented. Our proofs demonstrate that the blockchain layer does not represent a considered high extra transaction cost; it could be regarded as despicable for the economy of the consumer considering costs and benefits.

The fast pace of development of the Internet and the Coronavirus Disease (COVID-19) pandemic have considerably impacted the educative sector, encouraging the constant transformation of the teaching/learning strategies and more in technological areas as Educational Software Engineering. Web programming, a fundamental topic in Software Engineering and Cloud-based applications, deals with various critical challenges in education, such as learning continuous emerging technological tools, plagiarism detection, generating innovative learning environments, among others. Continual change and even more change with the current digitization becomes a challenge for teachers and students who cannot depend on traditional educational methods. The article presents a sustainable teaching/learning methodology for web programming courses in Engineering Education using project-based learning adaptable to the continuous web technological advances. The methodology has been developed and improved during 9 years, 15 groups, and 3 different universities. Our results demonstrate that the methodology is adaptable with new technologies that might arise; it also presents the advantages of avoiding plagiarism in students and a personalized induction for every specific student in the learning process.