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Ion Bernstein instability as a possible source for oxygen ion cyclotron harmonic waves
Get PDFThis paper demonstrates that an ion Bernstein instability can be a possible source for recently reported electromagnetic waves with frequencies at or near the singly ionized oxygen ion cyclotron frequency, Omega(+)(O), and its harmonics. The particle measurements during strong wave activity revealed a relatively high concentration of oxygen ions (similar to 15%) whose phase space density exhibits a local peak at energy similar to 20 keV. Given that the electron plasma-to-cyclotron frequency ratio is omega(pe)/Omega(e) greater than or similar to 1, this energy corresponds to the particle speed v/v(A) . greater than or similar to 0.3, where v(A) is the oxygen Alfven speed. Using the observational key plasma parameters, a simplified ion velocity distribution is constructed, where the local peak in the oxygen ion velocity distribution is represented by an isotropic shell distribution. Kinetic linear dispersion theory then predicts unstable Bernstein modes at or near the harmonics of Omega(+)(O) and at propagation quasi-perpendicular to the background magnetic field, B-0. If the cold ions are mostly protons, these unstable modes are characterized by a low compressibility (vertical bar delta B-parallel to vertical bar(2)/vertical bar delta B vertical bar(2) less than or similar to 0.01), a small phase speed (v(ph) similar to 0.2v(A)), a relatively small ratio of the electric field energy to the magnetic field energy (between 10(-4) and 10(-3)), and the Poynting vector directed almost parallel to B-0. These linear properties are overall in good agreement with the properties of the observed waves. We demonstrate that superposition of the predicted unstable Bernstein modes at quasi-perpendicular propagation can produce the observed polarization properties, including the minimum variance direction on average almost parallel to B-0.PublishedYe
Thermal Spikes Caused by the Urban Heat Island Effect Result in Differential Egg Survival of a Non-native Lizard (Anolis cristatellus)
Get PDFEmbryonic development in ectotherms is very sensitive to abiotic nest conditions. In reptiles, high incubation temperatures often result in relatively short incubation periods and large hatching size, but extremely high temperatures can result in cardiac arrest and death. Human altered habitats, which potentially create novel thermal conditions in the soil due to the urban heat island effect, may therefore create new selection pressures for developing embryos. The urban heat island effect can increase temperatures in cities as much as 12° C, and our preliminary data suggests that soil temperatures differ markedly between urban and natural areas in locations where reptiles deposit eggs. We measured the temperatures of potential nest sites of the Puerto Rican Crested Anole (Anolis cristatellus) in both urban and natural areas of Miami-Dade county where this lizard and several other anole species are naturalized. We bred crested anoles in the lab and subjected their eggs to 5 incubation treatments that mimic potential temperature regimes from our field data, three of which included a thermal spike 1/4 of the way through embryonic development. Preliminary results suggest that thermal spikes increase metabolism and reduce egg survival and that each are a function of the magnitude of the spike. These results suggest that urban environments create novel selection pressures that potentially result in embryonic adaptation to novel temperature regimes or in novel nest-site selection strategies by females.N
Against Egology: Ethics and Style in George Eliot and Emmanuel Levinas
No full textArticle from the George Eliot Review, digitized and hosted by the George Eliot Review Online.Publishe
Evaluating the Role of Parenting in Bullying Prevention
Get PDFThe aim of this evaluation study is to examine possible moderating effects of adolescent perceived parenting on the effectiveness of the Be SAFE, Affirming, and Fair Environments (Be SAFE) bullying prevention curriculum. Using family systems theory, this evaluation focuses on the influence of parenting on the change in adolescent bullying attitudes and behaviors after completing an adapted version of the Be SAFE bullying prevention curriculum. Findings show that on average adolescents reported engaging in more bullying behaviors after participating in the Be SAFE program, and adolescents who perceived their parents to be permissive reported significantly greater increases in bullying behaviors than adolescents who perceived their parents to be authoritarian and authoritative
Ramp-Up Your Worksheets
No full textCreating worksheets for instruction sessions that require students to think critically can be a challenge, especially when the librarian only has 50-minutes to introduce and discuss a concept. I will share strategies for developing in-class worksheets that require students to grapple with complex ideas, allowing for meaningful learning experiences despite time limitations beyond our control.N
Discovery and evolution of novel hemerythrin genes in annelid worms
Get PDFBACKGROUND: Despite extensive study on hemoglobins and hemocyanins, little is known about hemerythrin (Hr) evolutionary history. Four subgroups of Hrs have been documented, including: circulating Hr (cHr), myohemerythrin (myoHr), ovohemerythrin (ovoHr), and neurohemerythrin (nHr). Annelids have the greatest diversity of oxygen carrying proteins among animals and are the only phylum in which all Hr subgroups have been documented. To examine Hr diversity in annelids and to further understand evolution of Hrs, we employed approaches to survey annelid transcriptomes in silico. RESULTS: Sequences of 214 putative Hr genes were identified from 44 annelid species in 40 different families and Bayesian inference revealed two major clades with strong statistical support. Notably, the topology of the Hr gene tree did not mirror the phylogeny of Annelida as presently understood, and we found evidence of extensive Hr gene duplication and loss in annelids. Gene tree topology supported monophyly of cHrs and a myoHr clade that included nHrs sequences, indicating these designations are functional rather than evolutionary. CONCLUSIONS: The presence of several cHrs in early branching taxa suggests that a variety of Hrs were present in the common ancestor of extant annelids. Although our analysis was limited to expressed-coding regions, our findings demonstrate a greater diversity of Hrs among annelids than previously reported.PublishedYe
Geographic structure in the Southern Ocean circumpolar brittle star Ophionotus victoriae (Ophiuridae) revealed from mtDNA and single-nucleotide polymorphism data
Get PDFMarine systems have traditionally been thought of as "open" with few barriers to gene flow. In particular, many marine organisms in the Southern Ocean purportedly possess circumpolar distributions that have rarely been well verified. Here, we use the highly abundant and endemic Southern Ocean brittle star Ophionotus victoriae to examine genetic structure and determine whether barriers to gene flow have existed around the Antarctic continent. Ophionotus victoriae possesses feeding planktotrophic larvae with presumed high dispersal capability, but a previous study revealed genetic structure along the Antarctic Peninsula. To test the extent of genetic differentiation within O. victoriae, we sampled from the Ross Sea through the eastern Weddell Sea. Whereas two mitochondrial DNA markers (16S rDNA and COI) were employed to allow comparison to earlier work, a 2b-RAD single-nucleotide polymorphism (SNP) approach allowed sampling of loci across the genome. Mitochondrial data from 414 individuals suggested three major lineages, but 2b-RAD data generated 1,999 biallelic loci that identified four geographically distinct groups from 89 samples. Given the greater resolution by SNP data, O. victoriae can be divided into geographically distinct populations likely representing multiple species. Specific historical scenarios that explain current population structure were examined with approximate Bayesian computation (ABC) analyses. Although the Bransfield Strait region shows high diversity possibly due to mixing, our results suggest that within the recent past, dispersal processes due to strong currents such as the Antarctic Circumpolar Current have not overcome genetic subdivision presumably due to historical isolation, questioning the idea of large open circumpolar populations in the Southern Ocean.PublishedYe
Tait Family Papers: Creating the Digital Collection
Get PDFMost archival collections will have more than one user group or audience. Anticipating the most likely audience(s) for a given collection and thinking about the needs of the expected audience(s) should help the repository worker when preparing the collection for use. This panel will use as an example the Tait Family Papers Collection, which contains the financial records and correspondence of the Tait family, 19th and early 20th century plantation owners in Wilcox County, Alabama. The panel will discuss this collection from three different audience perspectives: Speaker 1 will talk about the collection from the point of view of traditional archival practice for use by on-site researchers. Speaker 2 will talk about using this collection in teaching situations at Auburn University. Speaker 3 [this presentation] will talk about constructing a digital collection that respects the original materials but meets the needs of an off-site audience
Research Practices and Support Services in Agriculture at Auburn University
Get PDFThis study examines the current and emerging research practices of academic and extension faculty from the field of agriculture at Auburn University in order to identify the resources and services that faculty need to be successful in their research and related professional duties and activities. This is one of 19 studies with similar objectives that are being conducted at selected United States universities and colleges and the USDA's National Agricultural Library. We conducted in-person interviews of 15 faculty who responded to questions on their areas of research; research methodologies used in their research; sources of research information; standard information searching methods and approaches; publication practices; research trends; and challenges that impede the research process. Responses were audio-recorded, transcribed and then interview transcripts were coded to identify the key responses and major themes
Crossing the Divide: Admixture Across the Antarctic Polar Front Revealed by the Brittle Star Astrotoma agassizii
Get PDFThe Antarctic Polar Front (APF) is one of the most well-defined and persistent oceanographic features on the planet and serves as a barrier to dispersal between the Southern Ocean and lower latitudes. High levels of endemism in the Southern Ocean have been attributed to this barrier, whereas the accompanying Antarctic Circumpolar Current (ACC) likely promotes west-to-east dispersal. Previous phylogeographic work on the brittle star Astrotoma agassizii Lyman, 1875 based on mitochondrial genes suggested isolation across the APF, even though populations in both South American waters and the Southern Ocean are morphologically indistinguishable. Here, we revisit this finding using a high-resolution 2b-RAD (restriction-site-associated DNA) single-nucleotide polymorphism (SNP)-based approach, in addition to enlarged mitochondrial DNA data sets (16S rDNA, COI, and COII), for comparison to previous work. In total, 955 biallelic SNP loci confirmed the existence of strongly divergent populations on either side of the Drake Passage. Interestingly, genetic admixture was detected between South America and the Southern Ocean in five individuals on both sides of the APF, revealing evidence of recent or ongoing genetic contact. We also identified two differentiated populations on the Patagonian Shelf with six admixed individuals from these two populations. These findings suggest that the APF is a strong but imperfect barrier. Fluctuations in location and strength of the APF and ACC due to climate shifts may have profound consequences for levels of admixture or endemism in this region of the world.PublishedYe