A 3-dimensional numerical simulation of the atmospheric injection of aerosols by a hypothetical basaltic fissure eruption

Researchers simulated the atmospheric response to a hypothetical basaltic fissure eruption using heating rates based on the Roza flow eruption. The simulation employs the Colorado State University Regional Atmospheric Model (RAMS) with scavenging effects. The numerical model is a three-dimensional non-hydrostatic time-split compressible cloud/mesoscale model. Explicit microphysics include prediction of cloud, rain, crystal, and hail precipitation types. Nucleation and phoretic scavenging are predicted assuming that the pollutant makes an effective cloud droplet nucleus. Smoke is carried as a passive tracer. Long and short wave radiation heating tendencies, including the effects of the smoke, are parameterized. The longwave emission by the lava surface is neglected in the parameterization and included as an explicit heating term instead. A regional scale domain of 100 x 100 km in the horizontal and 22 km high is used. The horizontal grid spacing is taken to be 2 km and the vertical spacing is taken to be 0.75 km. The initial atmospheric state is taken to be horizontally homogenous and based on the standard atmospheric sounding. The fissure is assumed to be 90 km long and oriented in a zig/zag pattern

Conversaciones virtuales: Investigación y práctica en los intercambios de lengua en línea

Advances in digital technology have created interesting opportunities for language learners to engage in conversation with native speakers. These opportunities provide the possibility for tremendous growth in language and culture learning (Lewis & O’Dowd, 2016) in ways that until recently did not exist. These interactions can take a variety of forms. Some instructors create highly controlled interactions with specific activities and pre-assigned partners. Others students are asked to connect to social media style sites where they experience enormous autonomy in choosing when they interact, who they interact with, and what they speak about (Malerba, 2012). Online exchanges with native speakers also vary according to the linguistic competence of the speakers. Generally, online exchanges have been used with learners who are at intermediate or advanced skill levels. However, the present study builds on recent research suggesting that even novice level learners can benefit from interacting with native speakers online (Satar & Özdener, 2008; Schenker, 2017). In this study, the authors examined novice students’ perceptions of learning and changes in comfort level after participating in a series of online and in-person exchanges over the course of a semester. The study compared students’ perceptions of online interactions generally with those of in-person exchanges and also compared the results of the use of various services. Results suggest that students in all of the groups, online and in-person, felt more comfortable interacting with native speakers and felt that they improved their language skills by engaging in these activities. With that said, students in the in-person group tended to feel more comfortable speaking with native speakers, but students in most of the online groups felt that the one on one nature of the interactions in the online settings led to the most growth.Los avances en la tecnología digital han creado oportunidades interesantes para que los estudiantes de lengua participen en conversaciones con hablantes nativos. Estas oportunidades brindan la posibilidad de un enorme crecimiento en el aprendizaje de lenguas y culturas (Lewis & O’Dowd, 2016) en formas que hasta hace poco no existían. Estas interacciones pueden tomar una variedad de formas. Algunos instructores crean interacciones sumamente controladas con actividades específicas y compañeros asignados previamente. A otros estudiantes se les pide que se conecten a sitios al estilo de las redes sociales donde experimentan una enorme autonomía para elegir cuándo interactúan, con quién interactúan y de qué hablan (Malerba, 2012). Los intercambios en línea con hablantes nativos también varían de acuerdo con la competencia lingüística de los hablantes. En general, los intercambios en línea se han utilizado con estudiantes que se encuentran en los niveles intermedios o avanzados. Sin embargo, el presente estudio se basa en investigaciones recientes que sugieren que incluso los principiantes de nivel principiante pueden beneficiarse de la interacción en línea con hablantes nativos (Satar & Özdener, 2008; Schenker, 2017). En este estudio, los autores examinaron las percepciones de los estudiantes principiantes sobre el aprendizaje y los cambios en el nivel de comodidad después de participar en una serie de intercambios en línea y en persona en el transcurso de un semestre. El estudio comparó las percepciones de los estudiantes sobre las interacciones en línea en general con las de los intercambios en persona y también comparó los resultados del uso de diversos servicios. Los resultados sugieren que los estudiantes de todos los grupos, en línea y en persona, se sintieron más cómodos interactuando con hablantes nativos y sintieron que mejoraron sus habilidades lingüísticas al participar en estas actividades. Dicho esto, los estudiantes en el grupo en persona tienden a sentirse más cómodos al hablar con hablantes nativos, pero los estudiantes, en la mayoría de los grupos en línea, sintieron que la naturaleza de las interacciones en línea de hablar uno a uno condujo a un mayor crecimiento

The Influence of Service Planning Decisions on Rail Transit Success or Failure, MTI Report 08-04

Some United States metropolitan areas with rail transit systems enjoy ridership and productivity success while others do not. This study examines the experiences of 11 U.S. metropolitan areas with between one million and five million persons to better understand why some areas are successful and others are not. A particular focus is the role of service planning decisions in facilitating transit success. We find that successful transit systems are those that: 1) articulate a clear, multidestination vision for regional transit; 2) rely on rail transit as the system´s backbone; 3) recognize the importance of the non-CBD travel market; 4) encourage the use of transfers to reach a wider array of destinations; 5) recognize that rail transit alone is not enough to guarantee success; and 6) recognize the importance of serving regional destinations

Heritage Language Learners and Spanish for Specific Purposes: Bridging the Gap through Community Service Learning

The growth in the number of Spanish heritage language learners in languages for specific purposes classes has been accompanied by an increase in the number and types of community service learning programs in which these students can participate to better prepare them for future employment opportunities. In spite of the increase in the number of Spanish heritage language learners in the languages for specific purposes classroom, few studies have looked at these students in this setting and even fewer have looked at the role that community service learning can play in developing these learners’ domain-specific abilities. Through an analysis of research in the areas of heritage language learners, Spanish for specific purposes, and community service learning, this article discusses strategies to effectively teach Spanish heritage language learners in language for specific purposes classes and to develop their language and cultural knowledge through community service learning. In addition, we address many of the challenges that arise when connecting Spanish heritage language learners with community partners as well as the obstacles to the integration of community service learning into the Spanish for specific purposes curriculum. The article concludes providing suggestions on how community service can be used to help Spanish heritage language learners not only see the benefits of language for specific purposes courses but also transfer their skills to other fields of study

Digital Connections: Student Experiences in Online Language Exchanges

Exciting advances in technology have provided foreign language teachers with opportunities to connect students to native speakers of target languages. Much of the research in this area focuses on changes in proficiency or cultural sensitivity. Although valuable, the research is lacking in understanding students’ experiences online, including positive and negative feelings, challenges, as well as students’ overall opinions of the exchanges’ usefulness for learning. The present study used a mixed methods approach to examine the experiences of third-semester university students participating in online language exchanges with native speakers. A third-semester Spanish class at a large university consisting of 18 students was selected as a sample. Students were required to speak online with native Spanish speakers in the target language for 20 minutes each week. Students completed weekly surveys and a final survey, and three students were selected for semi-structured interviews. The data reveal common struggles that students face during online exchanges, methods students use for coping with these difficulties, areas of perceived growth, and social factors that affect students’ experiences. The article concludes with recommendations for what foreign language educators can do to support students in similar online exchanges

Life-history aspects of \u3ci\u3eChrosomus oreas\u3c/i\u3e (Mountain Redbelly Dace) in Catawba Creek, Virginia

Life-history aspects of Chrosomus oreas, Mountain Redbelly Dace, were identified using specimens collected monthly from Catawba Creek in Roanoke County, Virginia. Chrosomus oreas were found in depths up to 63.3 cm with a modest relationship between abundance and depth. The largest specimen examined was a female 64.68 mm standard length, 4.80 g eviscerated weight, and 36 months of age. The oldest specimens examined were 37 months of age suggesting a maximum lifespan of approximately three years. Spawning appears to occur from April to early July, with a mean of 243 oocytes (SD = 178) up to 1.61 mm diameter in gravid females. Males begin to reach sexual maturity by approximately one year of age and all males appear to be mature by two years of age. Females do not begin to reach sexual maturity until two years of age. The diet of C. oreas appears to be almost exclusively algae and detritus. Food intake largely mimics energetic investment in gonadic mass as it was lowest in August and generally increased until May. Weight of gut contents increases with size of specimen

A numerical study of the correspondence between paths in a causal set and geodesics in the continuum

This paper presents the results of a computational study related to the path-geodesic correspondence in causal sets. For intervals in flat spacetimes, and in selected curved spacetimes, we present evidence that the longest maximal chains (the longest paths) in the corresponding causal set intervals statistically approach the geodesic for that interval in the appropriate continuum limit.Comment: To the celebration of the 60th birthday of Rafael D. Sorki