344 research outputs found

    Academic Librarian Self-Image in Lore: How Shared Stories Convey and Define Our Sense of Professional Identity

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    Chapter 2 in the book: The Librarian Stereotype: Deconstructing Presentations and Perceptions of Information Work serves as a response to passionate discussions regarding how librarians are perceived. Through twelve chapters, the book reignites an examination of librarian presentation within the field and in the public eye, employing theories and methodologies from throughout the social sciences. The ultimate goal of this volume is to launch productive discourse and inspire action in order to further the positive impact of the information professions. Through deconstructing the perceived truths of our profession and employing a critical eye, we can work towards improved status, increased diversity, and greater acceptance of each other

    Introduction, Motivating Students on a Time Budget: Pedagogical Frames and Lesson Plans for In-Person and Online Information Literacy Instruction

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    Introduction to the book Motivating Students on a Time Budget: Pedagogical Frames and Lesson Plans for In-Person and Online Information Literacy Instruction, edited by Sarah Steiner and Miriam Rigby. The book begins with a section of research-based, broad-level considerations of student motivation as it relates to short-term information literacy instruction, both in person and online. It then moves into activities and lesson plans that highlight specific motivational strategies and pedagogies: Each encourages the spirit of play, autonomy, and active learning in a grade-free environment. Activities and plans cover everything from game-based learning to escape rooms to role playing to poetry, and are thoroughly explained to be easily incorporated at your campus

    The Ones That Got Away: Minimizing Missed Chats Using an Evidence Based Wait Time Standard

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    The study explores the length of time online chat (often dubbed “Ask a Librarian” or virtual reference) academic library patrons will wait before leaving without interacting with a library employee. The study investigators* reviewed 400 randomly selected transcripts from three institutions (Agnes Scott College (ASC), University of Georgia (UGA), and Western Carolina University (WCU)) to correlate wait time with patron engagement. The findings establish the ideal wait time on library chat service points is ninety seconds or fewer. Furthermore, the study indicates establishing a goal time for initial greeting within the first ninety seconds leads to a substantial decrease in the number of “missed” questions. *Study contributors are Sarah Steiner (WCU), Casey Long (ASC), and Amber Prentiss (UGA)

    Reaching Faculty During the Summer: Taking Inspiration from the Blogosphere

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    Librarians at Western Carolina University have performed scholarship-focused summer outreach to the teaching faculty for many years, primarily via in-person workshops. Since faculty often focus on scholarship rather than instruction during summers, our emphasis on research and publication was timely and appropriate. However, the in-person research workshops were poorly attended, as faculty who do not teach summer courses often do not come to campus

    Electroluminescence from Organometallic Lead Halide Perovskite-Conjugated Polymer Diodes

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    Organometallic lead perovskite-based solar cells can be converted to light-emitting diodes by engineering the current density. Diodes are fabricated with adjacent perovskite and conjugated polymer layers using orthogonal solvents. Under forward bias, these devices show simultaneous emission from both the luminescent conjugated polymer and the perovskite, providing direct information on electron and hole recombination as a function of device architecture and bias voltage.We gratefully acknowledge funding from the Engineering and Physical Sciences Research Council (EPSRC). A.K. acknowledges NRF-Singapore for a scholarship.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/aelm.20150000

    Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes

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    Copyright: © 2010 Stimpson et al.Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extrachromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.This work was supported by the Tumorzentrum Heidelberg/Mannheim grant (D.10026941)and by March of Dimes Research Foundation grant #1-FY06-377 and NIH R01 GM069514

    Alveolar hypoxia, alveolar macrophages, and systemic inflammation

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    Diseases featuring abnormally low alveolar PO2 are frequently accompanied by systemic effects. The common presence of an underlying inflammatory component suggests that inflammation may contribute to the pathogenesis of the systemic effects of alveolar hypoxia. While the role of alveolar macrophages in the immune and defense functions of the lung has been long known, recent evidence indicates that activation of alveolar macrophages causes inflammatory disturbances in the systemic microcirculation. The purpose of this review is to describe observations in experimental animals showing that alveolar macrophages initiate a systemic inflammatory response to alveolar hypoxia. Evidence obtained in intact animals and in primary cell cultures indicate that alveolar macrophages activated by hypoxia release a mediator(s) into the circulation. This mediator activates perivascular mast cells and initiates a widespread systemic inflammation. The inflammatory cascade includes activation of the local renin-angiotensin system and results in increased leukocyte-endothelial interactions in post-capillary venules, increased microvascular levels of reactive O2 species; and extravasation of albumin. Given the known extrapulmonary responses elicited by activation of alveolar macrophages, this novel phenomenon could contribute to some of the systemic effects of conditions featuring low alveolar PO2

    PtrWRKY19, a novel WRKY transcription factor, contributes to the regulation of pith secondary wall formation in Populus trichocarpa

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    WRKY proteins are one of the largest transcription factor families in higher plants and play diverse roles in various biological processes. Previous studies have shown that some WRKY members act as negative regulators of secondary cell wall formation in pith parenchyma cells. However, the regulatory mechanism of pith secondary wall formation in tree species remains largely unknown. In this study, PtrWRKY19 encoding a homolog of Arabidopsis WRKY12 was isolated from Populus trichocarpa. PtrWRKY19 was expressed in all tissues tested, with highest expression in stems, especially in pith. PtrWRKY19 was located in the nucleus and functioned as a transcriptional repressor. Ectopic expression of PtrWRKY19 in an atwrky12 mutant successfully rescued the phenotype in pith cell walls caused by the defect of AtWRKY12, suggesting that PtrWRKY19 had conserved functions for homologous AtWRKY12. Overexpression of PtrWRKY19 in poplar plants led to a significant increase in the number of pith parenchyma cells. qRT-PCR analysis showed that lignin biosynthesis-related genes were repressed in transgenic plants. In transcient reporter assays, PtrWRKY19 was identified to repress transcription from the PtoC4H2 promoter containing the conserved W-box elements. These results indicated that PtrWRKY19 may function as a negative regulator of pith secondary wall formation in poplar

    The ERI-6/7 Helicase Acts at the First Stage of an siRNA Amplification Pathway That Targets Recent Gene Duplications

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    Endogenous small interfering RNAs (siRNAs) are a class of naturally occuring regulatory RNAs found in fungi, plants, and animals. Some endogenous siRNAs are required to silence transposons or function in chromosome segregation; however, the specific roles of most endogenous siRNAs are unclear. The helicase gene eri-6/7 was identified in the nematode Caenorhabditis elegans by the enhanced response to exogenous double-stranded RNAs (dsRNAs) of the null mutant. eri-6/7 encodes a helicase homologous to small RNA factors Armitage in Drosophila, SDE3 in Arabidopsis, and Mov10 in humans. Here we show that eri-6/7 mutations cause the loss of 26-nucleotide (nt) endogenous siRNAs derived from genes and pseudogenes in oocytes and embryos, as well as deficiencies in somatic 22-nucleotide secondary siRNAs corresponding to the same loci. About 80 genes are eri-6/7 targets that generate the embryonic endogenous siRNAs that silence the corresponding mRNAs. These 80 genes share extensive nucleotide sequence homology and are poorly conserved, suggesting a role for these endogenous siRNAs in silencing of and thereby directing the fate of recently acquired, duplicated genes. Unlike most endogenous siRNAs in C. elegans, eri-6/7–dependent siRNAs require Dicer. We identify that the eri-6/7–dependent siRNAs have a passenger strand that is ∼19 nt and is inset by ∼3–4 nts from both ends of the 26 nt guide siRNA, suggesting non-canonical Dicer processing. Mutations in the Argonaute ERGO-1, which associates with eri-6/7–dependent 26 nt siRNAs, cause passenger strand stabilization, indicating that ERGO-1 is required to separate the siRNA duplex, presumably through endonucleolytic cleavage of the passenger strand. Thus, like several other siRNA–associated Argonautes with a conserved RNaseH motif, ERGO-1 appears to be required for siRNA maturation
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