18,812 research outputs found

    The value of taking notes during lectures

    Get PDF
    Running title: Taking notesIncludes bibliographical references (p. 42-47)Pursuant to contract no. 400-81-0030 of the National Institute of Educatio

    Student Engagement in a Team-Based Capstone Course: A Comparison of What Students Do and What Instructors Value

    Full text link
    Student engagement is an important consideration across all levels of education. The adoption of student-centered teaching methods is an effective way to increase student engagement. Student engagement is at risk when instructor expectations and student participation in purposeful engagement activities are not aligned. Traditionally, student engagement is measured at the institutional level, which proves less than useful to instructors who wish to gauge engagement in specific courses in higher education. In this study, we sought to determine classroom level engagement in a capstone farm management course recently converted to the team-based learning format by comparing student perceptions regarding participation in engagement-specific activities with the instructors’ perceived importance of those same activities. The Classroom-Level Survey of Student Engagement (CLASSE) was utilized to collect student participation and instructor importance data. Data were examined utilizing a 2x2 quadrant analysis. Congruence between student participation frequency and instructor importance was found between 73.7% of the educational activities, while discrepancies were found on 26.3% of educational activities. Overall, students who completed the team-based learning-structured farm management course were physically and psychologically engaged in the learning environment. It is recommended that team-based learning be implemented in other courses within agricultural education to examine its utility in other contexts

    Does text structure/summarization instruction facilitate learning from expository text?

    Get PDF
    The work upon which this publication is based was performed pursuant to Contract no. NIE-400-81-0030 of the National Institute of Educatio

    An overview of Precambrian rocks in Sonora

    Get PDF
    The oldest stratified rocks recognized in NW Sonora (and in Mexico) are deformed muscovite-quartz schists, quartzites, and biotite-quartzofeldspathic gneisses near Caborca, which are cut by calcalkaline intrusives ranging from 1,710 to 1,750 m.y. in age. Southwest of Caborca, upper amphibolite facies layered quattzofeldspathic and amphibolitic gneisses were apparently deformed and metamorphosed at about 1,660 ± 15 m.y. ago, concealing original lithologies and ages. In northeastern Sonora, a younger belt of eugeosynolinal strata, about 1,680 ± 20 m. y. old was tightly folded and metamorphosed to greenschist facies about 1,650 m.y. ago. Numerous granitic plutons intruded into the older Precambrian crust about 1,410 to 1,440 m.y. ago. These major intrusive masses are not known to have been accompanied by regional sedimentation or deformation. Rare, small plutons of micrographic granite added to the Precambrian crystalline complexes about 1,100 m.y. ago, are the youngest Precambrian igneous rocks recognized. They limit the age of a thick miogeoclinal sequence of unmetamorphosed quartzose sandstones, carbonates with numerous stromatolite horizons, and shales which rest nonconformably on them. The sequence is overlain without unconformity by a fossiliferous Lower Cambrian section. The northwestern and northeastern Precambrian suits appear to be separated by a Jurassic magmatic arc and a postulated shear structure of large lateral displacement. Both suites correlate northward into related belts in the SW United States. To the east they are concealed by Phanerozoic cover. Abrupt termination of Precambrian exposures south and west suggests major younger tectonic features which we suspect played important but undefined roles in the apparent absence of Precambrian basement under much of northern and west-central Mexico

    Earth Structure from Free Oscillations and Travel Times

    Get PDF
    An extensive set of reliable gross Earth data has been inverted to obtain a new estimate of the radial variations of seismic velocities and density in the Earth. The basic data set includes the observed mass and moment of inertia, the average periods of free oscillation (taken mainly from the Dziewonski-Gilbert study), and five new sets of differential travel-time data. The differential travel-time data consists of the times of PcP-P and ScS-S, which contain information about mantle structure, and the times of P′_(AB) - P′_(DF) and P′_(BC)-P′_(DF) which are sensitive to core structure. A simple but realistic starting model was constructed using a number of physical assumptions, such as requiring the Adams-Williamson relation to hold in the lower mantle and core. The data were inverted using an iterative linear estimation algorithm. By using baseline-insensitive differential travel times and averaged eigenperiods, a considerable improvement in both the quality of the fit and the resolving power of the data set has been realized. The spheroidal and toroidal data are fit on the average to 0·04 and 0·08 per cent, respectively. The final model, designated model B1, also agrees with Rayleigh and Love wave phase and group velocity data. The ray-theoretical travel times of P waves computed from model B1 are about 0·8s later than the 1968 Seismological Tables with residuals decreasing with distance, in agreement with Cleary & Hales and other recent studies. The computed PcP, PKP, and PKiKP times are generally within 0·5 s of the times obtained in recent studies. The travel times of S computed from B1 are 5–10 s later than the Jeffreys-Sullen Tables in the distance range 30° to 95°, with residuals increasing with distance. These S times are in general agreement with the more recent data of Kogan, Ibrahim & Nuttli, Lehmann, Cleary, and Bolt et al. Model B1 is characterized by an upper mantle with a high, 4·8 km s^(−1), S_n velocity and a normal, 3·33 g cm^(−3), density. A low-velocity zone for S is required by the data, but a possible low-velocity zone for compressional waves cannot be resolved by the basic data set. The upper mantle transition zone contains two first-order discontinuities at depths of 420 km and 671 km. Between these discontinuities the shear velocity decreases with depth. The radius of the core, fixed by PcP-P times and previous mode inversions, is 3485 km, and the radius of the inner core-outer core boundary is 1215 km. There are no other first-order discontinuities in the core model. The shear velocity in the inner core is about 3·5 km s^(−1)

    Robo-line storage: Low latency, high capacity storage systems over geographically distributed networks

    Get PDF
    Rapid advances in high performance computing are making possible more complete and accurate computer-based modeling of complex physical phenomena, such as weather front interactions, dynamics of chemical reactions, numerical aerodynamic analysis of airframes, and ocean-land-atmosphere interactions. Many of these 'grand challenge' applications are as demanding of the underlying storage system, in terms of their capacity and bandwidth requirements, as they are on the computational power of the processor. A global view of the Earth's ocean chlorophyll and land vegetation requires over 2 terabytes of raw satellite image data. In this paper, we describe our planned research program in high capacity, high bandwidth storage systems. The project has four overall goals. First, we will examine new methods for high capacity storage systems, made possible by low cost, small form factor magnetic and optical tape systems. Second, access to the storage system will be low latency and high bandwidth. To achieve this, we must interleave data transfer at all levels of the storage system, including devices, controllers, servers, and communications links. Latency will be reduced by extensive caching throughout the storage hierarchy. Third, we will provide effective management of a storage hierarchy, extending the techniques already developed for the Log Structured File System. Finally, we will construct a protototype high capacity file server, suitable for use on the National Research and Education Network (NREN). Such research must be a Cornerstone of any coherent program in high performance computing and communications

    THE INTRACELLULAR GROWTH OF BACTERIOPHAGES : II. THE GROWTH OF T3 STUDIED BY SONIC DISINTEGRATION AND BY T6-CYANIDE LYSIS OF INFECTED CELLS

    Get PDF
    The growth of the virus T3 has been followed by breaking up the complexes it forms with host cells at various stages in their development and then assaying the debris for active virus particles. Two independent methods for breaking up cells were used: sonic vibration and lysis by the T6-cyanide method previously used for the study of the growth of T4. During the first half of the latent period both treatments, as well as cyanide alone, destroyed the capacity of the complexes for producing daughter virus particles. Furthermore, the infecting particles could not be recovered from them during the first half of the latent period. After the complexes had had 12 minutes of incubation at 30°C. both methods freed daughter virus particles from them in numbers which increased steadily with time until, near the end of the rise period, the normal burst size was reached. In general the agreement between the two yields is so good that one may conclude that both methods liberate quantitatively the mature daughter T3 particles which exist in the complexes before normal lysis occurs

    Mines and Minerals of the Western Kentucky Fluorspar District

    Get PDF
    This map shows all the known and identified mines, mineral prospects, and igneous intrusions (dikes or sills) in the Western Kentucky Fluorspar District, compiled from thousands of maps and files, creating an up-to-date, comprehensive catalog for the district. The district has been extensively mined for more than 120 years and was once the largest producer of fluorspar (fluorite) in the United States. Millions of tons of vein ore minerals (fluorite, zinc, lead, and barite) has been produced from these mines, and substantial reserves still remain. New mining and exploration activity has renewed interest in the district, and the industry will benefit from the use of this new map. Historic iron ore mines are also included because of their immediate proximity to this mapped area

    The determination of the alkalinity of sea water

    Get PDF
    In a previous paper one of us (3) described a _ method for the determination of the alkalinity of sea water-then termed the buffer capacity of sea water. This method was very rapid, eliminated the need for a titration process, and was particularly advantageous when working under rigorous field conditions. However considerable difficulty was sometimes experienced in the preparation of color comparison standards from base-free sea water. The method was later improved by Mitchell and Rakestraw (2). The present paper deals with a modification of the original method. The glass electrode is used for the measurement of excess acid and gives a precision greater than that obtained with color standards. If suitable shelter is available the method may be performed as readily in the field as in the laboratory. Following is a description of the apparatus and the method used

    Pothole Repair in Pennsylvania

    Get PDF
    • …
    corecore