9,921 research outputs found
Phylogeny, Ontogeny and Distribution of the Ribbonfishes (Lampridiformes: Trachipteridae)
The ribbonfish family Trachipteridae (Lampridiformes) includes three well-defined genera (Trachipterus, Desmodema, and Zu), which are distributed worldwide throughout the pelagic marine environment as with most families of Lampridiformes, drastic changes in morphology occur throughout ontogeny due to extreme allometric growth. Combined with the rarity of specimens, this has led to the description of different life history stages as different species, rather than as part of the ontogenetic continuum of a single species. There is significant uncertainty concerning the ontogeny, distribution, nomenclature, number and phylogenetic affinity of trachipterid and other lampridiform genera.;The first chapter of my dissertation is a taxonomic review of of the family Trachipteridae. This chapter provides updated genus (Trachipterus, Desmodema, and Zu) and species descriptions ( Desmodema and Zu) and a synthesis of life history, biogeographic, and ontogenetic data for trachipterid fishes, including examination of an abundance of material from the western Pacific Ocean. Additionally, numerous new morphological observations are described and an updated key to the trachipterid genera, applicable to both juvenile and adult stages, is provided.;The phylogenetic systematics of all lampridiform genera (Metavelifer, Velifer, Lampris, Lophotus, Eumecichthys, Radiicephalus, Agrostichthys, Regalecus, Trachipterus, Desmodema, Zu) is examined in the second chapter of my dissertation. I used 62 morphological characters from across the ontogenetic continuum to test proposed hypotheses of genus-level relationships of Trachipteridae and familial monophyly of the Lampridiformes. All lampridiform families were recovered as monophyletic except for the Lophotidae, resulting in Eumecichthys as incertae sedis. The suborder Taeniosomoidei is proposed to reflect the monophyletic clade consisting on long-bodied lampridiforms. Trachipteridae is recovered as monophyletic sister group to Regalecidae. The superfamily Trachipteroidea is proposed to recognize this clade. However, within the Trachipteridae, a monophyletic clade consisting of Trachipterus + Zu is recovered but with low support
Keeping Up with the Virtual Joneses: The Practices, Meanings, and Consequences of Consumption in Second Life
Every day, thousands of people log into the virtual world of Second Life and collectively pay hundreds of thousands of dollars to purchase virtual goods. With an in-world economic system that is linked to offline economies and a wealth of user-generated content, the virtual world has a wide variety of goods available for consumption. These commodities, which include everything from clothes and cars to fantastical pets and flying airships, are computer code visually rendered on a screen, and cannot exist apart from the servers on which they are housed. Although they are virtual, goods in Second Life are widely bought, sold, and traded.
Through participant observation, surveys, interviews, and content analysis, this dissertation investigates the practices, meanings, and effects associated with the consumption of virtual goods. It considers the extensive consumption practices found in the worldās market and freebie economies, the degree to which Second Life residents consume virtual goods, and their consumption preferences. It also investigates the meanings associated with these practices, and examines the ways in which consumption is implicated in individuality, belonging, resistance, social status, and social and cultural capital. Finally, it argues that although there is significant consumption inequality within the world, the effects and perceptions of this inequality are moderated by factors including the virtual nature of the world, free and inexpensive virtual goods, a lack of stigmas, user-generated content, and resident attitudes. Although consumption is a practice that bears important meanings for residents and is heavily engaged, often in unequal ways, the moderating effects of the world make Second Life what can be termed a utopia of inequality
Interrogating fragments using a protein thermal shift assay
Protein thermal shift is a relatively rapid and inexpensive technique for the identification of low molecular weight compound interactions with protein targets. An increase in the melting temperature of the target protein in the presence of a test ligand is indicative of a promising ligand-protein interaction. Due to its simplicity, protein thermal shift is an attractive method for screening libraries and validating hits in drug discovery programs. The methodology has been used successfully in high throughput screens of small molecule libraries, and its application has been extended to report on protein-drug-like-fragment interactions. Here, we review how protein thermal shift has been employed recently in fragment-based drug discovery (FBDD) efforts, and highlight its application to protein-protein interaction targets. Multiple validation of fragment hits by independent means is paramount to ensure efficient and economical progress in a FBDD campaign. We discuss the applicability of thermal shift assays in this light, and discuss more generally what one does when orthogonal approaches disagree
Search for Gamma-ray Emission from Dark Matter Annihilation in the Large Magellanic Cloud with the Fermi Large Area Telescope
At a distance of 50 kpc and with a dark matter mass of
M, the Large Magellanic Cloud (LMC) is a natural target for indirect
dark matter searches. We use five years of data from the Fermi Large Area
Telescope (LAT) and updated models of the gamma-ray emission from standard
astrophysical components to search for a dark matter annihilation signal from
the LMC. We perform a rotation curve analysis to determine the dark matter
distribution, setting a robust minimum on the amount of dark matter in the LMC,
which we use to set conservative bounds on the annihilation cross section. The
LMC emission is generally very well described by the standard astrophysical
sources, with at most a excess identified near the kinematic center
of the LMC once systematic uncertainties are taken into account. We place
competitive bounds on the dark matter annihilation cross section as a function
of dark matter particle mass and annihilation channel.Comment: 33 pages, 22 figures Version 2: minor corrections and clarifications
after journal peer review proces
Search for Gamma-ray Emission from Dark Matter Annihilation in the Small Magellanic Cloud with the Fermi Large Area Telescope
The Small Magellanic Cloud (SMC) is the second-largest satellite galaxy of
the Milky Way and is only 60 kpc away. As a nearby, massive, and dense object
with relatively low astrophysical backgrounds, it is a natural target for dark
matter indirect detection searches. In this work, we use six years of Pass 8
data from the Fermi Large Area Telescope to search for gamma-ray signals of
dark matter annihilation in the SMC. Using data-driven fits to the gamma-ray
backgrounds, and a combination of N-body simulations and direct measurements of
rotation curves to estimate the SMC DM density profile, we found that the SMC
was well described by standard astrophysical sources, and no signal from dark
matter annihilation was detected. We set conservative upper limits on the dark
matter annihilation cross section. These constraints are in agreement with
stronger constraints set by searches in the Large Magellanic Cloud and approach
the canonical thermal relic cross section at dark matter masses lower than 10
GeV in the and channels.Comment: 17 pages, 11 figures. Accepted by PR
Some remarks on authentication systems
Brickell, Simmons and others have discussed doubly perfect authentication systems in which an opponent\u27s chance of deceiving the receiver is a minimum for a given number of encoding rules. Brickell has shown that in some instances to achieve this minimum the system needs to have splitting. Such a system uses a larger message space. Motivated by Brickell\u27s ideas we consider authentication systems with splitting and the problems of reducing the message space
Tell Your Story Well: How Embedded Librarians Demonstrate and Communicate Their Value
SLA Embedded Librarians Caucus Conference panel session from the Special Libraries Association 2018 Annual Conference, selected for the SLA "Best Of" Webinar series of the seven most highly-rated sessions from this SLA 2018 conference. Embedded librarians have unique opportunities and challenges in demonstrating and communicating their value. Metrics and communications have to be tailored to each situation, and can depend on the type of organization, the organizationās mission and strategy, and the personalities involved. In this panel session, experienced managers and librarians shared perspectives, principles, and examples for making sure others in your organization (especially the higher ups) understand the value librarians are adding in their embedded role. Moderator: Nadine Anderson. Panelists: *Jennifer Martin, Associate Librarian, Arizona Health Sciences Library *Ethel M. Salonen, Principal, Ollin AssociatesSLA Embedded Librarians Caucus Conference panel session from the Special Libraries Association 2018 Annual Conference, selected for the SLA "Best Of" Webinar series of the seven most highly-rated sessions from this SLA 2018 conference.https://deepblue.lib.umich.edu/bitstream/2027.42/150201/1/Tell Your Story Well - How Embedded Librarians Demonstrate and Communicate Their Value.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150201/2/2018-10-02 14.03 How Embedded Librarians Demonstrate and Communicate Their Value.mp4Description of Tell Your Story Well - How Embedded Librarians Demonstrate and Communicate Their Value.pdf : Presentation SlidesDescription of 2018-10-02 14.03 How Embedded Librarians Demonstrate and Communicate Their Value.mp4 : Webinar Recordin
Daily Sleep Quality is Associated with Daily Cognition in Late-Life
Background: Older adults often face sleep disturbance or cognitive decline that goes beyond the scope of normal aging. The present study examined the relationship between self-reported sleep quality and self-reported daytime attention in a community-dwelling sample of older men at the between-persons and within-persons levels of association.
Methods: Thirty-eight participants (M age =75.36 years, SD age =7.51 years, range=66-90 years) completed a twice-daily sleep diary for one week. Sleep quality and attention were assessed using a single-item 0-10 rating scales from the morning diary (āHow was the quality of your sleep last night?ā) and from the evening diary (āHow was your attention today?ā). A two-level multilevel model was parameterized with days nested within individuals to examine whether nightly sleep quality predicts an individualās daily attention rating.
Results: A multilevel model predicting self-reported attention revealed (1) older individuals who reported better sleep quality reported having better daily attention [Beta=0.64, t(248.15)=10.12, p\u3c0.001] and (2) following a day of above-average sleep quality, older individuals experienced above-average attention [Beta=0.16, t(259.79)=2.75, p=.006].
Conclusion: Not only was overall sleep quality associated with self-reported attention, but a good night\u27s sleep was associated with better self-reported next-day attention. Results point to the potential importance of fluctuations in sleep quality for daytime functioning. Interventions aimed at improving nightly sleep consistency may be worth exploring as methods to improve daytime cognitive functioning in older adults.
Support: This work was supported by the Sleep Research Society Foundation/Jazz Pharmaceuticals (001JP13, PI: Dzierzewski) and by the National Institute on Aging of the National Institutes of Health under Award Number K23AG049955 (PI: Dzierzewski), and National Heart Lung and Blood Institute at the National Institutes of Health under award number K24HL143055 (PI: Martin). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Department of Veterans Affairs.https://scholarscompass.vcu.edu/gradposters/1089/thumbnail.jp
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