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Abstract Student-created videos engage students’ interests, creativity, and content knowledge and enrich collaborative learning in STEM education. These videos enhance critical thinking and analytical skills, which are essential tools in the fields of science, technology, engineering, and mathematics (STEM). This study presents the results of such an assignment across several STEM areas (biology, chemistry, exercise science, information technology, and mathematics) at a minority-serving, liberal arts higher education institution in the southeast region of the United States. Undergraduate students (n = 557) across varied, online course modalities (synchronous and asynchronous) were required to create four problem-solving videos 3–8 min in duration. Assessment tools included a self-assessment of learning gains survey given to control and experimental groups and a post-video creation survey given only to experimental groups. Grade data was also collected from all sections. Comparing the experimental and control groups, students showed a statistically significant gain in their ability to give oral presentations, create videos, and edit videos. Qualitative data from free-response questions corroborate these gains and suggest that students also grew in content knowledge and conceptual understanding through these assignments. Our study implements a multimedia theoretical framework which suggests students learn more effectively from consuming presentations with both auditory and visual components. Our results suggest students see similar gains from producing presentations with both auditory and visual components. Further our results suggest that multimedia production enhances students’ presentation skills. From a practical perspective, this study suggests that faculty should incorporate student-created videos in online classes, which typically require oral presentations in person. Faculty are also advised to require oral and visual components within these videos to maximize learning gains from the perspective of a multimedia theoretical framework. more...

Introduction: Developmental defects of the enamel manifest before tooth eruption and include amelogenesis imperfecta, a rare disease of underlying gene mutations, and molar–incisor hypomineralization (MIH), a prevalent disease in children originating from environmental and epigenetic factors. MIH enamel presents as the abnormal enamel marked by loss of translucency, demarcation between the healthy and affected enamel, and reduced mineral content. The pathophysiology of opaque, demarcated enamel lesions is not understood; however, the retention of enamel proteins in the matrix has been suggested. Ameloblastin (Ambn) is an enamel protein of the secreted calcium-binding phosphoproteins (SCPPs) critical for enamel formation. When the Ambn gene is mutated or deleted, teeth are affected by hypoplastic amelogenesis imperfecta.Methods: In this study, enamel formation in mice was analyzed when transgenic Ambn was overexpressed from the amelogenin promoter encoding full-length Ambn. Ambn was under- and overexpressed at six increasing concentrations in separate mouse lines.Results: Mice overexpressing Ambn displayed opaque enamel at low concentrations and demarcated lesions at high concentrations. The severity of enamel lesions increased starting from the inner enamel close to the dentino-enamel junction (DEJ) to span the entire width of the enamel layer in demarcated areas. Associated with the opaque enamel were 17-kDa Ambn cleavage products, a prolonged secretory stage, and a thin basement membrane in the maturation stage. Ambn accumulations found in the innermost enamel close to the DEJ and the mineralization front correlated with reduced mineral content. Demarcated enamel lesions were associated with Ambn species of 17 kDa and higher, prolonged secretory and transition stages, a thin basement membrane, and shortened maturation stages. Hypomineralized opacities were delineated against the surrounding mineralized enamel and adjacent to ameloblasts detached from the enamel surface. Inefficient Ambn cleavage, loss of contact between ameloblasts, and the altered basement membrane curtailed the endocytic activity; thus, enamel proteins remained unresorbed in the matrix. Ameloblasts have the ability to distinguish between Ambn concentration and Ambn cleavage products through finely tuned feedback mechanisms. The under- or overexpression of Ambn in murine secretory ameloblasts results in either hypoplastic amelogenesis imperfecta or hypomineralization with opaque or sharply demarcated boundaries of lesions, similar to MIH. more...

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Donepezil (DPZ) is an acetylcholinesterase inhibitor used for the clinical treatment of mild cognitive impairment. However, DPZ has been reported to have adverse effects, including causing abnormal cardiac rhythm, insomnia, vomiting, and muscle cramps. However, the existence of these effects in subjects without Dementia is unknown. In this study, we use zebrafish to conduct a deeper analysis of the potential adverse effects of DPZ on the short-term memory and behaviors of normal zebrafish by performing multiple behavioral and biochemical assays. Adult zebrafish were exposed to 1 ppm and 2.5 ppm of DPZ. From the results, DPZ caused a slight improvement in the short-term memory of zebrafish and induced significant elevation in aggressiveness, while the novel tank and shoaling tests revealed anxiolytic-like behavior to be caused by DPZ. Furthermore, zebrafish circadian locomotor activity displayed a higher reduction of locomotion and abnormal movement orientation in both low- and high-dose groups, compared to the control group. Biomarker assays revealed that these alterations were associated with an elevation of oxytocin and a reduction of cortisol levels in the brain. Moreover, the significant increases in reactive oxygen species (ROS) and malondialdehyde (MDA) levels in muscle tissue suggest DPZ exposure induced muscle tissue oxidative stress and muscle weakness, which may underlie the locomotor activity impairment. In conclusion, we show, for the first time, that chronic waterborne exposure to DPZ can severely induce adverse effects on normal zebrafish in a dose-dependent manner. These unexpected adverse effects on behavioral alteration should be carefully addressed in future studies considering DPZ conducted on zebrafish or other animals. more...

Ultraviolet B (UVB) radiation has drawn more attention over these past few decades since it causes severe DNA damage and induces inflammatory response. Serial gene profiling and high throughput data in UVB-associated phenomenon in human cultured cells or full rack of human skin have been investigated. However, results using different tissue models lead to ambiguity in UVB-induced pathways. In order to systematically understand the UVB-associated reactions, the zebrafish model was used, and whole organism gene profiling was performed to identify a novel biomarker which can be used to generate a new mechanistic approach for further screening on a UVB-related system biology. In this study, detailed morphological assays were performed to address biological response after receiving UVB irradiation at morphological, cellular, and molecular levels. Microarray screening and whole genome profiling revealed that there is an early onset expression of junbb in zebrafish embryos after UVB irradiation. Also, the identified novel biomarker junbb is more sensitive to UVB response than mmps which have been used in mouse models. Moreover, cellular and molecular response chronology after UVB irradiation in zebrafish provide a solid and fundamental mechanism for use in a UV radiation-associated study in the future. more...

El trabajo es una evaluación de la influencia de los factores no genéticos en el intervalo entre partos de búfalas de río, mediante los registros de 740 partos de 210 animales, pertenecientes a la Empresa Genética Maraguán, provincia de Camagüey, Cuba. A las variables sexo de la cría, rebaño, número de partos, época y el año del parto se les aplicó análisis de varianza múltiple. El paquete estadístico utilizado fue el SPSS. Los factores no genéticos ejercieron una influencia significativa (P < 0,01) sobre el intervalo entre partos, el cual alcanzó una media de 389,2 ± 6,3 días. La tendencia del intervalo entre partos para 2007 y 2010 es negativa. more...

El objetivo de esta investigación fue desarrollar el algoritmo de filtro de Kalman en Matlab y su posterior evaluación en la señal GPS para determinar las mejoras que se obtiene ante los diferentes tipos de errores q afecta a la señal en transmisión y recepción. Esta técnica permitió eliminar los diferentes tipos de errores producidos por el ruido térmico, multipath, la refracción entre otros, que afectan principalmente a receptores que trabajan en simple frecuencia. Para realizar la diferenciación se usó los archivos Rinex de los receptores ubicados en tierra, para lo cual se extrajo las medidas de pseudo-rango y la fase de portadora es un tiempo estimado, generando la señal código menos fase denominado (CMC) para luego ser filtrada permitiendo obtener la señal CMC-Suavizada. Para el análisis de datos se aplicó estadística descriptica, la misma que permitió identificar mediante gráficas las señales originales y corregidas por el algoritmo en varios. Como conclusión se determinó que los valores del tiempo de estabilidad del filtro de Kalman están en un rango de 300 a 1800 segundos permitiendo observar la disminución del error en la señal, es así que entre más grande sea el tiempo estimado se produce una mejora en la reducción de los errores de manera gradual con respecto a la señal original. PALABRAS CLAVE: Telecomunicaciones; sistema de posicionamiento global; archivos rinex; filtro de Kalman; error ionosférico; Matlab ANALYSIS FOR CORRECTION OF ERRORS IN THE GPS SIGNAL ABSTRACT The objective of this investigation was to develop the Kalman filter algorithm in Matlab and its subsequent evaluation in the GPS signal to determine the improvements obtained in the different types of errors that affect the signal in transmission and reception. This technique allowed to eliminate the different types of errors produced by thermal noise, multipath, refraction among others, which mainly affect receivers that work in simple frequency. To perform the differentiation, the Rinex files of the receivers located on the ground were used, for which the pseudorange measurements were extracted and the carrier phase is an estimated time, generating the code signal less called phase (CMC) and then being filtered allowing get the CMC-Smoothing signal. For the analysis of data, descriptive statistics were applied, which allowed the identification of the original and corrected signals by several algorithms by means of graphs. In conclusion, it was determined that the Kalman filter stability time values are in a range of 300 to 1800 seconds, allowing the decrease in the error in the signal to be observed, so that the larger the estimated time an improvement in the Error reduction gradually with respect to the original signal. KEYWORDS: Telecommunications; global positioning system; rinex files; Kalman filter; ionospheric error; Matlab. more...