Investigating the Relationship between Instructors’ Use of Active Learning Strategies and Students’ Conceptual Understanding and Affective Changes in Introductory Biology: A Comparison of Two Active-Learning Environments

In response to calls for reform in undergraduate biology education, we conducted research examining how varying active-learning strategies impacted students’ conceptual understanding, attitudes, and motivation in two sections of a large-lecture introductory cell and molecular biology course. Using a quasi-experimental design, we collected quantitative data to compare participants’ conceptual understanding, attitudes, and motivation in the biological sciences across two contexts that employed different active-learning strategies and that were facilitated by unique instructors. Students participated in either graphic organizer/worksheet activities or clicker-based case studies. After controlling for demographic and presemester affective differences, we found that students in both active-learning environments displayed similar and significant learning gains. In terms of attitudinal and motivational data, significant differences were observed for two attitudinal measures. Specifically, those students who had participated in graphic organizer/worksheet activities demonstrated more expert-like attitudes related to their enjoyment of biology and ability to make real-world connections. However, all motivational and most attitudinal data were not significantly different between the students in the two learning environments. These data reinforce the notion that active learning is associated with conceptual change and suggests that more research is needed to examine the differential effects of varying active- learning strategies on students’ attitudes and motivation in the domain

Treatment of an aneurysmal bone cyst in a young dog: A case report

Background: An aneurysmal bone cyst (ABC) is a rare benign lytic lesion affecting the medullary canal of long bones. It has been widely reported in human medicine, but rarely described in domestic animals. Objective: To report the surgical treatment and long term follow-up of a dog affected by ABC. Methods: An 8-month-old, intact female Weimaraner was presented with lameness affecting the left front limb and progressive swelling of the mid-distal radius. Survey radiographs revealed a mid-distal diaphyseal radial lesion. Fine needle aspirates, biopsy, CT scan and histopathology results supported the diagnosis of ABC. Treatment consisted of partial corticotomy of the affected radius, filling of the cystic cavity with demineralised bone matrix and autologous bone graft and stabilisation using lag screws and a neutralisation plate. Results: The long-term follow-up, at 36 post-operative months, showed no recurrence of the cyst and bone modelling. Comparing preoperative radiographs with those at 36 months, bone modelling reduced the radial area by 23.3% in the craniocaudal radiographic view and 30% in the mediolateral projection. Conclusions: This treatment was sucessful in the case here described, with a 3 years follow-up

Identificación de agentes infecciosos asociados con Diarrea Neonatal Bovina en la Sabana de Bogotá

RESUMENObjetivo. Determinar los agentes infecciosos asociados causalmente a la presentación de Diarrea Neonatal Bovina (DNB) en terneros menores de 5 semanas de vida, procedentes de fincas lecheras y de producción mixta de la Sabana de Bogotá. Materiales y métodos. Se seleccionaron por conveniencia 21 fincas, se realizó seguimiento de 620 terneros desde el nacimiento hasta las 5 semanas de edad, se tomaron muestras de materia fecal de los animales que presentaron cuadro clínico de diarrea y de terneros clínicamente sanos como controles pareados. Se realizaron pruebas de ELISA para diagnóstico de E.coli F5, Rotavirus, Coronavirus, Cryptosporidium sp., y Salmonella sp., prueba de Ritchie para diagnóstico de Giardia sp., y tinción de Ziehl Neelsen modificada para Cryptosporidium sp. Se evaluó la asociación epidemiológica entre los agentes y la presentación de diarrea usando prueba de c2, seguido de un modelo de regresión logística (p<0.05). Resultados. Se encontró en la prueba de ELISA que de la totalidad de las muestras, 51 (38.3%), 26 (19.7%), 10 (7.5%) y 1 (0.75%) fueron positivas a Cryptosporidium sp., rotavirus, E coli F5 y coronavirus, respectivamente. Los animales positivos a Rotavirus por la prueba de ELISA y a Cryptosporidium sp., por la técnica de Ziehl Neelsen modificada tuvieron 2.6 y 7.0 veces mayor probabilidad que los demás animales de presentar DNB, respectivamente. Conclusiones. Los resultados presentados son los primeros que muestran el papel y la importancia del Cryptosporidium sp., y del Rotavirus en la DNB en las explotaciones ganaderas de la Sabana de Bogotá y en Colombia

Identificación de agentes infecciosos asociados con Diarrea Neonatal Bovina en la Sabana de Bogotá

RESUMEN Objetivo. Determinar los agentes infecciosos asociados causalmente a la presentación de Diarrea Neonatal Bovina (DNB) en terneros menores de 5 semanas de vida, procedentes de fincas lecheras y de producción mixta de la Sabana de Bogotá. Materiales y métodos. Se seleccionaron por conveniencia 21 fincas, se realizó seguimiento de 620 terneros desde el nacimiento hasta las 5 semanas de edad, se tomaron muestras de materia fecal de los animales que presentaron cuadro clínico de diarrea y de terneros clínicamente sanos como controles pareados. Se realizaron pruebas de ELISA para diagnóstico de E.coli F5, Rotavirus, Coronavirus, Cryptosporidium sp., y Salmonella sp., prueba de Ritchie para diagnóstico de Giardia sp., y tinción de Ziehl Neelsen modificada para Cryptosporidium sp. Se evaluó la asociación epidemiológica entre los agentes y la presentación de diarrea usando prueba de c2, seguido de un modelo de regresión logística (p<0.05). Resultados. Se encontró en la prueba de ELISA que de la totalidad de las muestras, 51 (38.3%), 26 (19.7%), 10 (7.5%) y 1 (0.75%) fueron positivas a Cryptosporidium sp., rotavirus, E coli F5 y coronavirus, respectivamente. Los animales positivos a Rotavirus por la prueba de ELISA y a Cryptosporidium sp., por la técnica de Ziehl Neelsen modificada tuvieron 2.6 y 7.0 veces mayor probabilidad que los demás animales de presentar DNB, respectivamente. Conclusiones. Los resultados presentados son los primeros que muestran el papel y la importancia del Cryptosporidium sp., y del Rotavirus en la DNB en las explotaciones ganaderas de la Sabana de Bogotá y en Colombia

Distance protection algorithm for multiterminal HVDC systems using the Hilbert–Huang transform

Multiterminal high-voltage direct current (HVDC) systems still need advances in terms of protection in order to improve their reliability. In this context, the distance protection can play a major role by adding selectivity to the existing DC fault detection algorithms. Hence, the present work proposes a non-unit DC distance protection algorithm that uses the frequency of the DC voltage transient oscillation to estimate the distance of the fault. The DC voltage transient frequency is extracted using the Hilbert–Huang transform and compared with a pre-defined frequency/distance curve. The technique was evaluated by simulating faults in a four-terminal symmetric monopole multiterminal HVDC system. In the simulation environment the algorithm was fully selective for faults within the first protection zone and had a correct operation rate of 94% or more for faults located in the second protection zone. To further validate the presented technique, the proposed algorithm was embedded in a digital signal controller, running in real-time. In all performed tests in hardware, the faults were correctly detected and identified as being internal or external. The results indicate that the proposed algorithm could be used in real-world applications, in conjunction with fault detection techniques, adding selectivity to multiterminal DC protection schemes

Assessment of multi-use offshore platforms: structure classification and design challenges

As the world continues to experience problems including a lack of seafood and high energy demands, this paper provides an assessment for integrated multi-use offshore platforms (MUPs) as a step towards exploiting open seawater in a sustainable way to harvest food and energy. The paper begins with background about MUPs, including information regarding what an MUP is and why it is used. The potential energy technologies that can be involved in an offshore platform are introduced while addressing similar applications all over the world. The paper presents the state of the art of MUP structures on the light of EU-funded programs. An MUP would have a positive impact on various marine activities such as tourism, aquaculture, transport, oil and gas and leisure. However, there are concerns about the negative impact of MUPs on the marine environment and ecosystem. Building an MUP with 100% renewable energy resources is still a challenge because a large storage capacity must be considered with a well-designed control system. However, marine bio-mass would play a vital role in reducing battery size and improving power supply reliability. Direct Current (DC) systems have never been considered for offshore platforms, but they could be a better alternative as a simpler control system that requires with lower costs, has lower distribution losses, and has an increased system efficiency, so studying the feasibility of using DC systems for MUPs is required