74 research outputs found

    A Virtuous Circle of Student Engagement: The Tech Corner

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    How can a culture of student innovation and interdisciplinary creativity be fostered when library facilities and / or budget do not accommodate a maker space? We allowed students to help develop a new collection of devices and equipment, the Tech Corner, launched in early 2016. We seek to provide ready access to unique, easy-to-use devices that support creativity, curricular work and recreation but may be too expensive for our average student to purchase. Student focus groups helped design the branding, marketing, and a starter collection of items that include virtual reality headsets, digital art brushes, tablet-compatible MIDI keyboards, digital microscopes, cameras, and pocket projectors. Liberal loan periods encourage off-campus, longer-term use, and circulation is limited to student account types. We plan to refresh the collection annually with new, student-recommended devices. We are building a virtuous circle of student engagement in a variety of ways. Students who complete a survey about each device receive promotional items and are registered in a prize raffle. Users are encouraged to share what they create for displays on our website and in library buildings. A website allows students to learn about the items, see how other students have used them, complete the survey, and sign up for email news. Polls circulated throughout the academic year via the website and social media will allow students to suggest and vote for new collection items. Assessment will include circulation statistics for this and other media items, survey feedback, and use-case submissions. Assessment data is in the attached supplemental file

    What is the relationship between photospheric flow fields and solar flares?

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    We estimated photospheric velocities by separately applying the Fourier Local Correlation Tracking (FLCT) and Differential Affine Velocity Estimator (DAVE) methods to 2708 co-registered pairs of SOHO/MDI magnetograms, with nominal 96-minute cadence and ~2" pixels, from 46 active regions (ARs) from 1996-1998 over the time interval t45 when each AR was within 45^o of disk center. For each magnetogram pair, we computed the average estimated radial magnetic field, B; and each tracking method produced an independently estimated flow field, u. We then quantitatively characterized these magnetic and flow fields by computing several extensive and intensive properties of each; extensive properties scale with AR size, while intensive properties do not depend directly on AR size. Intensive flow properties included moments of speeds, horizontal divergences, and radial curls; extensive flow properties included sums of these properties over each AR, and a crude proxy for the ideal Poynting flux, the total |u| B^2. Several magnetic quantities were also computed, including: total unsigned flux; a measure of the amount of unsigned flux near strong-field polarity inversion lines, R; and the total B^2. Next, using correlation and discriminant analysis, we investigated the associations between these properties and flares from the GOES flare catalog, when averaged over both t45 and shorter time windows, of 6 and 24 hours. We found R and total |u| B^2 to be most strongly associated with flares; no intensive flow properties were strongly associated with flares.Comment: 57 pages, 13 figures; revised content; added URL to manuscript with higher-quality image

    Structural and functional effects of acoustic exposure in goldfish: evidence for tonotopy in the teleost saccule

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    <p>Abstract</p> <p>Background</p> <p>Mammalian and avian auditory hair cells display tonotopic mapping of frequency along the length of the cochlea and basilar papilla. It is not known whether the auditory hair cells of fishes possess a similar tonotopic organization in the saccule, which is thought to be the primary auditory receptor in teleosts. To investigate this question, we determined the location of hair cell damage in the saccules of goldfish (<it>Carassius auratus</it>) following exposure to specific frequencies. Subjects were divided into six groups of six fish each (five treatment groups plus control). The treatment groups were each exposed to one of five tones: 100, 400, 800, 2000, and 4000 Hz at 176 dB re 1 μPa root mean squared (RMS) for 48 hours. The saccules of each fish were dissected and labeled with phalloidin in order to visualize hair cell bundles. The hair cell bundles were counted at 19 specific locations in each saccule to determine the extent and location of hair cell damage. In addition to quantification of anatomical injury, hearing tests (using auditory evoked potentials) were performed on each fish immediately following sound exposure. Threshold shifts were calculated by subtracting control thresholds from post-sound exposure thresholds.</p> <p>Results</p> <p>All sound-exposed fish exhibited significant hair cell and hearing loss following sound exposure. The location of hair cell loss varied along the length of the saccule in a graded manner with the frequency of sound exposure, with lower and higher frequencies damaging the more caudal and rostral regions of the saccule, respectively. Similarly, fish exposed to lower frequency tones exhibited greater threshold shifts at lower frequencies, while high-frequency tone exposure led to hearing loss at higher frequencies. In general, both hair cell and hearing loss declined as a function of increasing frequency of exposure tone, and there was a significant linear relationship between hair cell loss and hearing loss.</p> <p>Conclusions</p> <p>The pattern of hair cell loss as a function of exposure tone frequency and saccular rostral-caudal location is similar to the pattern of hearing loss as a function of exposure tone frequency and hearing threshold frequency. This data suggest that the frequency analysis ability of goldfish is at least partially driven by peripheral tonotopy in the saccule.</p

    The Grizzly, March 9, 2006

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    Two Juniors Attend C.O.O.L. Idealist National Conference in Tennessee • Celebration of Student Achievement • SPINT: Overview of House Projects • Understanding Abortion • Imperfect World of Auguste Rodin • Kelly Stirs Up Laughs • Marche aux Puces and Other Shopping Advice • Opinions: Letter to the Editor; Gimme Fiction Drips with Musical Ambition; Line Between Personal Offense and Free Speech • Bears Crush Crusaders • Respect!https://digitalcommons.ursinus.edu/grizzlynews/1709/thumbnail.jp

    Infrared plasmons propagate through a hyperbolic nodal metal

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    Metals are canonical plasmonic media at infrared and optical wavelengths, allowing one to guide and manipulate light at the nanoscale. A special form of optical waveguiding is afforded by highly anisotropic crystals revealing the opposite signs of the dielectric functions along orthogonal directions. These media are classified as hyperbolic and include crystalline insulators, semiconductors, and artificial metamaterials. Layered anisotropic metals are also anticipated to support hyperbolic waveguiding. However, this behavior remains elusive, primarily because interband losses arrest the propagation of infrared modes. Here, we report on the observation of propagating hyperbolic waves in a prototypical layered nodal-line semimetal ZrSiSe. The observed waveguiding originates from polaritonic hybridization between near-infrared light and nodal-line plasmons. Unique nodal electronic structures simultaneously suppress interband loss and boost the plasmonic response, ultimately enabling the propagation of infrared modes through the bulk of the crystal

    Cytochrome P450-derived eicosanoids and vascular dysfunction in coronary artery disease patients

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    Accumulating preclinical and epidemiologic evidence has emerged to suggest that modulation of cytochrome P450 (CYP)-mediated eicosanoid metabolism may be a viable vascular protective therapeutic strategy for the secondary prevention of coronary artery disease (CAD). The functional relationship between CYP-derived eicosanoid metabolite levels and vascular dysfunction in humans with established CAD, however, has not been evaluated. Therefore, we characterized the relationship between inter-individual variation in soluble epoxide hydrolase (sEH) and CYP ω-hydroxylase metabolism and established vascular function phenotypes predictive of prognosis in a cohort of patients with atherosclerotic cardiovascular disease

    Crystal Structures of Malonyl-Coenzyme A Decarboxylase Provide Insights into Its Catalytic Mechanism and Disease-Causing Mutations

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    Malonyl-coenzyme A decarboxylase (MCD) is found from bacteria to humans, has important roles in regulating fatty acid metabolism and food intake, and is an attractive target for drug discovery. We report here four crystal structures of MCD from human, Rhodopseudomonas palustris, Agrobacterium vitis, and Cupriavidus metallidurans at up to 2.3 Å resolution. The MCD monomer contains an N-terminal helical domain involved in oligomerization and a C-terminal catalytic domain. The four structures exhibit substantial differences in the organization of the helical domains and, consequently, the oligomeric states and intersubunit interfaces. Unexpectedly, the MCD catalytic domain is structurally homologous to those of the GCN5-related N-acetyltransferase superfamily, especially the curacin A polyketide synthase catalytic module, with a conserved His-Ser/Thr dyad important for catalysis. Our structures, along with mutagenesis and kinetic studies, provide a molecular basis for understanding pathogenic mutations and catalysis, as well as a template for structure-based drug design

    Structural Comparison of Human Mammalian Ste20-Like Kinases

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    BACKGROUND: The serine/threonine mammalian Ste-20 like kinases (MSTs) are key regulators of apoptosis, cellular proliferation as well as polarization. Deregulation of MSTs has been associated with disease progression in prostate and colorectal cancer. The four human MSTs are regulated differently by C-terminal regions flanking the catalytic domains. PRINCIPAL FINDINGS: We have determined the crystal structure of kinase domain of MST4 in complex with an ATP-mimetic inhibitor. This is the first structure of an inactive conformation of a member of the MST kinase family. Comparison with active structures of MST3 and MST1 revealed a dimeric association of MST4 suggesting an activation loop exchanged mechanism of MST4 auto-activation. Together with a homology model of MST2 we provide a comparative analysis of the kinase domains for all four members of the human MST family. SIGNIFICANCE: The comparative analysis identified new structural features in the MST ATP binding pocket and has also defined the mechanism for autophosphorylation. Both structural features may be further explored for inhibitors design. ENHANCED VERSION: This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S1
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