1,918 research outputs found

    FLARR Pages #40: Foreign Language in the Rural High Schools (Continued)

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    FLARR Pages #41: Foreign Language in the Rural High Schools

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    FLARR Pages #39: Perceptions of Foreign Language Education in the Rural High School

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    This study was conducted by the foreign language instructor of a rural school district in Northwestern Minnesota. The population of the high school (grades nine through twelve) is 144 students. The racial composition of the district is nearly 100% white. The district is classified as low-income with 41.3% of the district\u27s children qualifying for free or reduced hot lunch. Of the most recent three classes, an average of 39% of graduates planned to attend a four-year college, 37% planned to attend a two-year college, and 24% planned to enter the work force. This study evolved from the observation by the researcher that foreign language study was perceived by some as unnecessary, impractical or even frivolous. Some students, parents and even faculty did not see foreign language as a necessity in high school education. The goal of the study was three-fold: to investigate the beliefs and attitudes toward foreign language study in the community, to try to determine why these beliefs existed, and to investigate how foreign language can better be promoted as an important course of study for all students. An important note is that Spanish is the only foreign language offered to the students of the district. This may affect the student\u27s choice to study foreign language, if the student would have preferred a different language, for example

    Dispersal of meiofauna in a turbulent tidal creek

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    Traditionally meiofauna have been viewed as strictly infaunal organisms adapted for life between sediment grains. Recent evidence has shown that marine meiofauna also occur in the water column. A set of field experiments investigated processes controlling the abundance of meiofauna in the water column. The transport of meiofauna in a tidal creek was identified to be primarily a passive process resulting from mechanical removal due to current scour. Drifting meiofauna included interstitial, burrowing, and epibenthic species. Copepods, foraminiferans, and juvenile bivalves were suspended in greatest numbers relative to their sediment abundances. Suspension of meiofauna was greatest for species residing in the upper sediment layers and/or occasionally crawling about on the sediment surface. Suspended meiofauna and sediment were well-mixed within the water column, suggesting that behavioral control over water column dispersal was limited once the animals were in the water. Suspension of meiofauna was not a function of winds, time of day, lunar cycle (neap vs. spring tides), or the abundance of meiofauna in the sediment. The abundance of meiofauna in the water was determined primarily by the magnitude of the friction velocity (u.). The emerging concept is that in habitats where water currents are strong enough to lead to sediment scour, meiofauna dispersal is a two-step process with erosion rather than active water column entry (modified by behavior patterns for some species) and subsequent mixing and transport as passive particles

    Effects of Pituitary Stalk-transection and Type of Barrier on Pituitary and Luteal Function During the Estrous Cycle of the Ewe

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    Effects of pituitary stalk-transection on plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH) prolactin (PRL) and progesterone were investigated during the estrous cycle of ewes. Pituitary stalk (SS) or sham (SH) transection was performed on day 1 (estrus = day 0) of the estrous cycle. A Teflon or Silastic barrier was placed between the cut ends of the stalk to prevent reorganization of the portal vasculature. Immediately following surgery, pulsatile administration of gonadotropin releasing hormone (GnRH, 200 ng/hr) or .9% NaCl was initiated and continued for the duration of the experiment. Estradiol benzoate (EB, 50 μg im) was administered to all ewes on day 3. Mean concentrations of LH were greater in SS ewes than in SH ewes (P\u3c.05). There was a trend (P=.06) for the concentration of LH to be higher in ewes with Teflon compared with Silastic barriers between the cut ends of the stalk. Infusion of GnRH elevated concentrations of LH in both SS and SH ewes (P\u3c.05). Concentrations of progesterone were reduced (P\u3c.01) in saline-infused SS ewes while infusion of GnRH in SS ewes maintained concentrations of progesterone similar to saline-infused SH ewes. The concentrations of FSH or PRL were unaffected by SS, type of barrier or treatment with GnRH. Administration of EB failed to induce a surge of LH except in a SH ewe infused with GnRH. Ewes were more responsive to infusion of GnRH following SS than after SH as reflected by increased plasma concentrations of LH and progesterone

    The Geology and Geochemistry of the Agamenticus Complex, York, Maine

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    Guidebook for field trips in southern and west-central Maine, October 13, 14 and 15, 1989: New England Intercollegiate Geological Conference 81st annual meeting: Trip A-1; C-

    Coherent Propagation of Polaritons in Semiconductor Heterostructures: Nonlinear Pulse Transmission in Theory and Experiment

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    The influence of coherent optical nonlinearities on polariton propagation effects is studied within a theory-experiment comparison. A novel approach that combines a microscopic treatment of the boundary problem in a sample of finite thickness with excitonic and biexcitonic nonlinearities is introduced. Light-polarization dependent spectral changes are analyzed for single-pulse transmission and pump-probe excitation

    The Endothelium: The Vascular Information Exchange

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    Maintenance of adequate blood flow to tissues and organs requires that endothelial cells dynamically respond in a stimulus-specific manner to elicit appropriate changes in smooth muscle contractility and thus, arterial diameter. Endothelial cells can be stimulated directly by increases in blood flow and by humoral factors acting on surface receptors, as well as through flux of second messengers from smooth muscle cells activated by release of neurotransmitters from perivascular nerves. The ability of endothelial cells to generate stimulus-specific responses to these diverse inputs is facilitated by organization of ion channels and signaling proteins into microdomains that permit finely-tuned, spatially-restricted Ca2+ events to differentially activate key effectors such as nitric oxide (NO) synthase and Ca2+-activated K+ (KCa) channels. NO is a diffusible mediator which acts locally to cause vasodilation. Opening of KCa channels causes hyperpolarization of the endothelial membrane potential which spreads to surrounding smooth muscle cells to also cause local vasodilation. However, once initiated, hyperpolarization also spreads longitudinally through the endothelium to effect coordinated changes in blood flow within multiple arterial segments. Thus, the signaling pathways activated by a particular stimulus determine whether it’s effects on arterial diameter are localized or can impact blood flow at the level of the vascular bed
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