851 research outputs found

    Why Do They Do It? A Case Study of Factors Influencing Part-Time Faculty to Seek Employment at a Community College

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    The purpose of this qualitative study was to discover the motivational factors influencing part-time faculty employment within the community college from the perspective of the part-time faculty. The study examined these reported motivational factors for differences influenced by age, gender, and employment status. A survey was distributed to a random sample of part-time faculty members at a large metropolitan community college in the Southeastern United States. Participants were asked to respond to categorical demographic questions and survey questions to determine workplace satisfaction. Three open-ended questions were presented to obtain in-depth information about the motivational factors leading adjunct faculty to seek employment at the community college. Findings reveal that motivation is a result of interest in working within a discipline, working with students, and achieving personal satisfaction

    Tracking the Amide I and αCOO− Terminal ν(C=O) Raman Bands in a Family of L-Glutamic Acid-Containing Peptide Fragments: A Raman and DFT Study

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    The E-hook of β-tubulin plays instrumental roles in cytoskeletal regulation and function. The last six C-terminal residues of the βII isotype, a peptide of amino acid sequence EGEDEA, extend from the microtubule surface and have eluded characterization with classic X-ray crystallographic techniques. The band position of the characteristic amide I vibration of small peptide fragments is heavily dependent on the length of the peptide chain, the extent of intramolecular hydrogen bonding, and the overall polarity of the fragment. The dependence of the E residue’s amide I ν(C=O) and the αCOO− terminal ν(C=O) bands on the neighboring side chain, the length of the peptide fragment, and the extent of intramolecular hydrogen bonding in the structure are investigated here via the EGEDEA peptide. The hexapeptide is broken down into fragments increasing in size from dipeptides to hexapeptides, including EG, ED, EA, EGE, EDE, DEA, EGED, EDEA, EGEDE, GEDEA, and, finally, EGEDEA, which are investigated with experimental Raman spectroscopy and density functional theory (DFT) computations to model the zwitterionic crystalline solids (in vacuo). The molecular geometries and Boltzmann sum of the simulated Raman spectra for a set of energetic minima corresponding to each peptide fragment are computed with full geometry optimizations and corresponding harmonic vibrational frequency computations at the B3LYP/6-311++G(2df,2pd) level of theory. In absence of the crystal structure, geometry sampling is performed to approximate solid phase behavior. Natural bond order (NBO) analyses are performed on each energetic minimum to quantify the magnitude of the intramolecular hydrogen bonds. The extent of the intramolecular charge transfer is dependent on the overall polarity of the fragment considered, with larger and more polar fragments exhibiting the greatest extent of intramolecular charge transfer. A steady blue shift arises when considering the amide I band position moving linearly from ED to EDE to EDEA to GEDEA and, finally, to EGEDEA. However, little variation is observed in the αCOO− ν(C=O) band position in this family of fragments

    Synchronous spawning of nursery-raised elkhorn coral (Acropora palmata) outplanted to reefs in the Florida Keys (United States)

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    Here, we provide the first reports of spawning activity by Acropora palmata colonies outplanted to reefs in Florida, USA. In 2020, we observed light spawning from A. palmata colonies five years after they had been outplanted on two Florida reefs. In 2021 and 2022, we observed outplanted A. palmata colonies spawning synchronously with other nearby (<3 m) outplants and wild colonies more than 100 m away. During the 2022 spawning event, some colonies spawned in as few as four years after they had been outplanted. Among all spawning seasons, gametes collected from the outplanted colonies yielded high fertilization rates and viable larvae. These observations are promising for A. palmata restoration as they indicate fragments of A. palmata can spawn four years after outplanting and that efforts to restore A. palmata may be close to achieving the first step towards self-sustaining populations that can produce viable larvae, resulting in an increase in the population’s genotypic diversity upon successful recruitment to the reef

    Cartan subalgebras in C*-algebras of Hausdorff etale groupoids

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    The reduced C∗C^*-algebra of the interior of the isotropy in any Hausdorff \'etale groupoid GG embeds as a C∗C^*-subalgebra MM of the reduced C∗C^*-algebra of GG. We prove that the set of pure states of MM with unique extension is dense, and deduce that any representation of the reduced C∗C^*-algebra of GG that is injective on MM is faithful. We prove that there is a conditional expectation from the reduced C∗C^*-algebra of GG onto MM if and only if the interior of the isotropy in GG is closed. Using this, we prove that when the interior of the isotropy is abelian and closed, MM is a Cartan subalgebra. We prove that for a large class of groupoids GG with abelian isotropy---including all Deaconu--Renault groupoids associated to discrete abelian groups---MM is a maximal abelian subalgebra. In the specific case of kk-graph groupoids, we deduce that MM is always maximal abelian, but show by example that it is not always Cartan.Comment: 14 pages. v2: Theorem 3.1 in v1 incorrect (thanks to A. Kumjain for pointing out the error); v2 shows there is a conditional expectation onto MM iff the interior of the isotropy is closed. v3: Material (including some theorem statements) rearranged and shortened. Lemma~3.5 of v2 removed. This version published in Integral Equations and Operator Theor

    Trading water for carbon in the future : effects of elevated CO2 and warming on leaf hydraulic traits in a semiarid grassland

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    The effects of climate change on plants and ecosystems are mediated by plant hydraulic traits, including interspecific and intraspecific variability of trait phenotypes. Yet, integrative and realistic studies of hydraulic traits and climate change are rare. In a semiarid grassland, we assessed the response of several plant hydraulic traits to elevated CO2 (+200 ppm) and warming (+1.5 to 3°C; day to night). For leaves of five dominant species (three graminoids and two forbs), and in replicated plots exposed to 7 years of elevated CO2, warming, or ambient climate, we measured: stomatal density and size, xylem vessel size, turgor loss point, and water potential (pre-dawn). Interspecific differences in hydraulic traits were larger than intraspecific shifts induced by elevated CO2 and/or warming. Effects of elevated CO2 were greater than effects of warming, and interactions between treatments were weak or not detected. The forbs showed little phenotypic plasticity. The graminoids had leaf water potentials and turgor loss points that were 10% to 50% less negative under elevated CO2; thus, climate change might cause these species to adjust their drought resistance strategy away from tolerance and toward avoidance. The C4 grass also reduced allocation of leaf area to stomata under elevated CO2, which helps explain observations of higher soil moisture. The shifts in hydraulic traits under elevated CO2 were not, however, simply due to higher soil moisture. Integration of our results with others' indicates that common species in this grassland are more likely to adjust stomatal aperture in response to near-term climate change, rather than anatomical traits; this contrasts with apparent effects of changing CO2 on plant anatomy over evolutionary time. Future studies should assess how plant responses to drought may be constrained by the apparent shift from tolerance (via low turgor loss point) to avoidance (via stomatal regulation and/or access to deeper soil moisture)

    Decadal comparison of a diminishing coral community: a study using demographics to advance inferences of community status

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    The most common coral monitoring methods estimate coral abundance as percent cover, either via in situ observations or derived from images. In recent years, growing interest and effort has focused on colony-based (demographic) data to assess the status of coral populations and communities. In this study, we relied on two separate data sets (photo-derived percent cover estimates, 2002–12, and opportunistic in situ demographic sampling, 2004 and 2012) to more fully infer decadal changes in coral communities at a small, uninhabited Caribbean island. Photo-derived percent cover documented drastic declines in coral abundance including disproportionate declines in Orbicella spp. While overall in situ estimates of total coral density were not different between years, densities of several rarer taxa were. Meandrina meandrites and Stephanocoenia intersepta increased while Leptoseris cucullata decreased significantly, changes that were not discernable from the photo-derived cover estimates. Demographic data also showed significant shifts to larger colony sizes (both increased mean colony sizes and increased negative skewness of size frequency distributions, but similar maximum colony sizes) for most taxa likely indicating reduced recruitment. Orbicella spp. differed from this general pattern, significantly shifting to smaller colony sizes due to partial mortality. Both approaches detected significant decadal changes in coral community structure at Navassa, though the demographic sampling provided better resolution of more subtle, taxon-specific changes

    Rotation Periods of Open Cluster Stars, II

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    We present the results from a photometric monitoring program of 21 stars observed during 1992 in the Pleiades and Alpha Persei open clusters. Period determinations for 16 stars are given, 13 of which are the first periods reported for these stars. Brightness variations for an additional five cluster stars are also given. One K dwarf member of the a Per cluster is observed to have a period of rotation of only 4.39 hr, perhaps the shortest period currently known among BY Draconis variables. The individual photometric measurements have been deposited with the NSSDC. Combining current X-ray flux determinations with known photometric periods, we illustrate the X-ray activity/rotation relation among Pleiades K dwarfs based on available data
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