COVID-19 and the Transition to Online Learning in the Basic Course: Examining Effects on Student Learning

Objectives: This study examines how the transition to remote delivery during the spring of 2020 affected student learning in the basic communication course. Methods: Participants in three different course delivery modes (face-to-face, online, and live interactive) were enrolled in a public speaking course with standardized adaptive reading quizzes, exams, and speech assignments. Participants completed several measures over the course of the semester and had their responses paired up with their end-of-semester grade book data. Results: Results of this study indicate that students who were enrolled in a face-to-face course and transitioned online during the COVID-19 pandemic were outperformed by online and learning interactive students in several of the standardized assignments in the course. Conclusions: Overall, face-to-face (FtF) students performed four percentage points lower in the course than the learning interactive and online groups while also demonstrating more emotional interest in the course than the other two groups. Implication for Theory and/or Practice: In future transitions to remote learning, FtF students may experience greater disruption than existing online students. Instructors should be mindful of this finding in transitioning to remote learning during the semester

Investigations on the individual and maternal components of calving performance in cattle

International audienc

Einsatz einer Extrapolationsmethode bei der Versagensanalyse thermozyklisch beanspruchter Bauteile

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Datos preliminares de las inclusiones fluidas (petróleo y acuosas) en las fracturas cementadas de las Fms. Corones y Armàncies, Eoceno, Pirineo oriental

Las calizas del Eoceno del Pirineo sur-oriental están afectadas por fracturas con direcciones N-NE, buzamientos subverticales (55-72º), espesores centimétricos y longitudes de varios metros. En ocasiones también se observan cavidades vacuolares. Tanto las fracturas como las cavidades vacuolares están rellenas por cementos carbonáticos que no ocluyen totalmente la porosidad. Además, la presencia de indicios de petróleo es muy abundante en las fracturas que afectan a la parte alta de la Fm Armàncies (Cuisiense, Eoceno) y son menos abundantes, pero están también presentes, en la Fm Corones (Cuisiense inferior). El objetivo principal de este trabajo es caracterizar los tipos de inclusiones fluidas (IF) en los cementos carbonáticos que rellenan fracturas como primera aproximación a la historia de migración del petróleo. El estudio detallado de petrografía, fluorescencia y microtermometría ha revelado que en la Fm Corones aparecen tres tipos de inclusiones con dos fases (líquido y vapor): i) IF de petróleo con fluorescencia amarilla; ii) IF de petróleo con fluorescencia amarilla y color marrón en luz transmitida; ambos tipos de IF aparecen como trazas de pequeña longitud que afectan sólo a uno o dos cristales de calcita, lo cual sugiere un origen secundario; iii) IF acuosas de tamaños muy pequeño (5-10 μm) que aparecen en los bordes de los cristales indicando un origen primario. En la Fm Armàncies aparecen cuatro tipos de inclusiones con dos fases (líquido y vapor): i) IF de petróleo con fluorescencia amarilla; ii) IF de petróleo con fluorescencia amarilla y color marrón en luz transmitida; iii) IF petróleo con fluorescencia azul y azul intenso, que son las más abundantes; todas las IF de petróleo aparecen como trazas de gran continuidad, paralelas a los márgenes de las fracturas, lo cual sugiere un origen primario; iv) IF acuosas que son muy escasas y aparecen como trazas. En resumen, los datos preliminares del estudio de inclusiones fluidas sugieren que el petróleo en la Fm Armàncies migró a través de fracturas de forma coetánea con la precipitación de los cementos carbonáticos. Por el contrario, el petróleo fue atrapado en el cemento carbonático de las fracturas de la Fm Corones, pero no durante su precipitación, sino posteriorment

Spatio-temporal variations of climate along possible African-Arabian routes of H. sapiens expansion

Eastern Africa and Arabia were major hominin hotspots and critical crossroads for migrating towards Asia during the late Pleistocene. To decipher the role of spatiotemporal environmental change on human occupation and migration patterns, we remeasured the marine core from Meteor Site KL 15 in the Gulf of Aden and reanalyzed its data together with the aridity index from ICDP Site Chew Bahir in eastern Africa and the wet-dry index from ODP Site 967 in the eastern Mediterranean Sea using linear and nonlinear time series analysis. These analyses show major changes in the spatiotemporal paleoclimate dynamics at 400 and 150 ka BP (thousand years before 1950), presumably driven by changes in the amplitude of the orbital eccentricity. From 400 to 150 ka BP, eastern Africa and Arabia show synchronized wet-dry shifts, which changed drastically at 150 ka BP. After 150 ka BP, an overall trend to dry climate states is observable, and the hydroclimate dynamics between eastern Africa and Arabia are negatively correlated. Those spatio-temporal variations and interrelationships of climate potentially influenced the availability of spatial links for human expansion along those vertices. We observe positively correlated network links during the supposed out-of-Africa migration phases of H. sapiens. Furthermore, our data do not suggest hominin occupation phases during specific time intervals of humid or stable climates but provide evidence of the so far underestimated potential role of climate predictability as an important factor of hominin ecological competitiveness

From the Feynman-Schwinger representation to the non-perturbative relativistic bound state interaction

We write the 4-point Green function in QCD in the Feynman-Schwinger representation and show that all the dynamical information are contained in the Wilson loop average. We work out the QED case in order to obtain the usual Bethe-Salpeter kernel. Finally we discuss the QCD case in the non-perturbative regime giving some insight in the nature of the interaction kernel.Comment: 25 pages, RevTex, 3 figures included, typos corrected, to appear in Phys. Rev. D 5