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Cutting the Commute: Assess Authentically and Still Arrive on Time
Get PDFWhile the importance of assessment for student learning is widely recognized, instructors are often reluctant to sacrifice valuable class time for this activity. This presentation discusses the Auburn University Libraries instruction program's use of in-class student worksheets and other hands-on activities to integrate authentic assessment into classroom instruction. By applying rubrics to active learning exercises that are already part of the curriculum, instructors gather valuable data about student progress in attaining key information literacy skills. Classroom learning activities and tasks include identifying keywords and developing synonyms for database searches and articulating differences between popular and scholarly sources.N
Hydrogen sulfide cytoprotective signaling isendothelial nitric oxide synthase-nitricoxide dependent
Get PDFPrevious studies have demonstrated that hydrogen sulfide (H2S) protects against multiple cardiovascular disease states in a similar manner as nitric oxide (NO). H2S therapy also has been shown to augment NO bioavailability and signaling. The purpose of this study was to investigate the impact of H2S deficiency on endothelial NO synthase (eNOS) function, NO production, and ischemia/reperfusion (I/R) injury. We found that mice lacking the H2S-producing enzyme cystathionine γ-lyase (CSE) exhibit elevated oxidative stress, dysfunctional eNOS, diminished NO levels, and exacerbated myocardial and hepatic I/R injury. In CSE KO mice, acute H2S therapy restored eNOS function and NO bioavailability and attenuated I/R injury. In addition, we found that H2S therapy fails to protect against I/R in eNOS phosphomutant mice (S1179A). Our results suggest that H2S-mediated cytoprotective signaling in the setting of I/R injury is dependent in large part on eNOS activation and NO generation.PublishedYe
The Comprehensive Inner Magnetosphere-Ionosphere Model
Get PDFSimulation studies of the Earth's radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model were merged to form a Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. CIMI solves for many essential quantities in the inner magnetosphere, including ion and electron distributions in the ring current and radiation belts, plasmaspheric density, Region 2 currents, convection potential, and precipitation in the ionosphere. It incorporates whistler mode chorus and hiss wave diffusion of energetic electrons in energy, pitch angle, and cross terms. CIMI thus represents a comprehensive model that considers the effects of the ring current and plasmasphere on the radiation belts. We have performed a CIMI simulation for the storm on 5-9 April 2010 and then compared our results with data from the Two Wide-angle Imaging Neutral-atom Spectrometers and Akebono satellites. We identify the dominant energization and loss processes for the ring current and radiation belts. We find that the interactions with the whistler mode chorus waves are the main cause of the flux increase of MeV electrons during the recovery phase of this particular storm. When a self-consistent electric field from the CRCM is used, the enhancement of MeV electrons is higher than when an empirical convection model is applied. We also demonstrate how CIMI can be a powerful tool for analyzing and interpreting data from the new Van Allen Probes mission.PublishedYe
Three Noteworthy Vascular Plant Records from Alabama
Get PDFThree vascular plant taxa are documented as new or noteworthy to the flora of Alabama. Astragalus obcordatus,
previously unknown from the state, is here substantiated for the first time from Alabama based on a collection made from Dallas County. Eleocharis rostellata and Pilea fontana, formerly represented in the state from one location each are newly reported from Baldwin County and Jackson County, respectively.PublishedYe
Performance of soybean cultivars in Alabama, 2014
No full textoai:aurora.auburn.edu:11200/49931"December 2014.
Maternal life history of white-tailed deer: factors affecting fetal sex allocation, conception timing, and senescence
Get PDFQuestions: How does maternal condition and regional variation in resource abundance
affect fetal sex ratio allocation, timing of litter conception, and decreased fecundity due to
senescence?
Data studied: We used female white-tailed deer (Odocoileus virginianus) maternal age and
mass and reproductive tract data (number and sex of fetuses) collected from 1995 to 2011
throughout Alabama.
Methods: Fetal sex ratio allocation: We aged collected fetuses to determine conception date
and examined the effects of maternal age and mass, litter size, and conception timing (relative
to site-specific average conception timing). Timing of litter conception: We examined effects
of maternal characteristics. Fecundity: We examined effects of maternal age and mass. In all
models, we assessed the effect of regional variation in resource abundance.
Conclusions: Fetal sex ratio allocation: The only significant predictor was conception timing,
and sons were more likely as conception date was closer to the peak of breeding. We did not
find support for Trivers-Willard or the local resource competition hypothesis. Timing of litter
conception: Maternal age, mass, and their interaction (maternal age × mass) explained conception timing, with smaller females conceiving further from the mean conception date among
younger females and larger females conceiving further from the mean conception date among
older females (likely related to reproductive output in the prior breeding season). Fecundity:
Not previously demonstrated, we found support for age-related reproductive senescence in
female white-tailed deer.PublishedYe
Solar cycle variation of plasma mass density in the outer magnetosphere: Magnetoseismic analysis of toroidal standing Alfven waves detected by Geotail
No full textWe study the variation of plasma mass density in the outer magnetosphere over a solar cycle using mass density estimated from the frequency of fundamental toroidal standing Alfven waves observed by the Geotail spacecraft. We identify wave events using ion bulk velocity data covering 1995-2006 and use events in the 0400-0800 magnetic local time sector for statistical analysis. We find that the F-10.7 index is a dominant controlling factor of the mass density. For the equatorial mass density rho(*)(eq) that is normalized to the value at L = 11, we obtain an empirical formula log rho(*)(eq)= -0.136 + 1.78 x 10(-3) = 10(-3) F-10.7, where the units of rho(*)(eq) and F-10.7 are amu cm(-3) and solar flux units (sfu; 1 sfu =10(-22) W m(-2) Hz(-1)), respectively. This formula indicates that rho(*)(eq) changes by a factor of 1.8, if F-10.7 changes from 70 sfu (solar minimum) to 210 sfu (solar maximum). A formula derived in a similar manner using GOES magnetometer data indicates that, for the same range of F-10.7, the mass density at L approximate to 7 varies by a factor of 4.1 We attribute the smaller factor at L = 11 to the lower O+/H+ number density ratio at higher L, the stronger F-10.7 dependence of the O+ outflow rate than the H+ outflow rate, and entry of solar wind H+ ions to the outer magnetosphere.Publishe
Investigation of storm time magnetotail and ion injection using three-dimensional global hybrid simulation
Get PDFDynamics of the near-Earth magnetotail associated with substorms during a period of extended southward interplanetary magnetic field is studied using a three-dimensional (3-D) global hybrid simulation model that includes both the dayside and nightside magnetosphere, for the first time, with physics from the ion kinetic to the global Alfvenic convection scales. It is found that the dayside reconnection leads to the penetration of the dawn-dusk electric field through the magnetopause and thus a thinning of the plasma sheet, followed by the magnetotail reconnection with 3-D, multiple flux ropes. Ion kinetic physics is found to play important roles in the magnetotail dynamics, which leads to the following results: (1) Hall electric fields in the thin current layer cause a systematic dawnward ion drift motion and thus a dawn-dusk asymmetry of the plasma sheet with a higher (lower) density on the dawnside (duskside). Correspondingly, more reconnection occurs on the duskside. Bidirectional fast ions are generated due to acceleration in reconnection, and more high-speed earthward flow injections are found on the duskside than the dawnside. Such finding of the dawn-dusk asymmetry is consistent with recent satellite observations. (2) The injected ions undergo the magnetic gradient and curvature drift in the dipole-like field, forming a ring current. (3) Ion particle distributions reveal multiple populations/beams at various distances in the tail. (4) Dipolarization of the tail magnetic field takes place due to the pileup of the injected magnetic fluxes and thermal pressure of injected ions, where the fast earthward flow is stopped. Oscillation of the dipolarization front is developed at the fast-flow braking, predominantly on the dawnside. (5) Kinetic compressional wave turbulence is present around the dipolarization front. The cross-tail currents break into small-scale structures with where is the perpendicular wave number. A sharp dip of magnetic field strength is seen just in front of the sharp rise of the magnetic field at the dipolarization front, mainly on the duskside. (6) A shear flow-type instability is found on the duskside flank of the ring current plasma, whereas a kinetic ballooning instability appears on the dawnside. (7) Shear Alfvenic waves and compressional waves are generated from the tail reconnection, and they evolve into kinetic Alfvn waves in the dipole-like field region. Correspondingly, multiple field-aligned current filaments are generated above the auroral ionosphere.Publishe
Modeling the loss of inner belt protons by magnetic field line curvature scattering
Get PDFThe sudden loss of energetic protons in the inner radiation belt has been observed during geomagnetic storms. It is hypothesized that this sudden loss occurs because of changes in the geomagnetic field configuration which lead to a breakdown of the first adiabatic invariant, mu, in a process called magnetic field line curvature scattering or mu scattering. Comparison of observations to various analytic model predictions for mu scattering induced loss has, however, yielded discrepancies. To better understand how well the analytic models predict the proton loss, test particle simulations are carried out for various magnetic field configurations. Although our simulation results agree well with the analytic models for single-scattering events, the results after cumulative mu scattering can show significant disagreement with the theoretical predictions based on analytic models. In particular, we find the assumption that protons with predicted initial delta mu/mu 0.01 or epsilon > 0.1 are ultimately lost overestimates the proton loss. Based on the test particle simulation results, we develop a new empirical model, called the epsilon-onset model, to predict the minimum value of e at which all protons of a given pitch angle and energy can be assumed to be lost due to mu scattering. By applying our epsilon-onset model as the variable cutoff condition between trapping and detrapping, we obtain very good agreement between theoretical predictions and the simulation results for a range of Kp, suggesting that the epsilon-onset model can potentially serve as an easy-to-use and more reliable predictor of inner belt proton loss due to mu scattering than the previously used fixed-valued cutoff conditions.PublishedYe