3,979 research outputs found

    Astrometric Microlensing Constraints on a Massive Body in the Outer Solar System with Gaia

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    A body in Solar orbit beyond the Kuiper belt exhibits an annual parallax that exceeds its apparent proper motion by up to many orders of magnitude. Apparent motion of this body along the parallactic ellipse will deflect the angular position of background stars due to astrometric microlensing ("induced parallax"). By synoptically sampling the astrometric position of background stars over the entire sky, constraints on the existence (and basic properties) of a massive nearby body may be inferred. With a simple simulation, we estimate the signal-to-noise for detecting such a body -- as function of mass, heliocentric distance, and ecliptic latitude -- using the anticipated sensitivity and temporal cadences from Gaia (launch 2011). A Jupiter-mass (M_Jup) object at 2000 AU is detectable by Gaia over the whole sky above 5-sigma, with even stronger constraints if it lies near the ecliptic plane. Hypotheses for the mass (~3M_Jup), distance (~20,000 AU) and location of the proposed perturber ("Planet X") which gives rise to long-period comets may be testable.Comment: 17 pages, 6 figures. Figures revised, new figure added, minor text revisions. Accepted to ApJ, to appear in the Dec 10, 2005 issue (v635

    Examination of Differences in the Clinical Presentation of Veterans with Combat-related and Military Sexual-related Posttraumatic Stress Disorder

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    The primary goal of this study was to examine the psychodiagnostic properties of the Minnesota Multiphasic Personality Inventory (MMPI-2) F-2-8 profile as well as the clinical cutoff scores on the PK and PS scales for PTSD assessment in a sample of U.S. military veterans with PTSD diagnoses related to combat experience and how they differ from those veterans with PTSD diagnoses identified as survivors of military sexual trauma. This study used a retrospective archival design to access and analyze MMPI-2 profiles of veterans drawn from the VA Informatics and Computing Infrastructure (VINCI). This study had three independent variables, PTSD diagnosis, gender, and trauma type, which had three levels: combat trauma (n = 4,339), military sexual trauma (n = 2,083), and no trauma identified (n = 23,085). Results showed that all three PTSD measures analyzed (PK, PS, F-2-8) were statistically effective at differentiating PTSD diagnosed from non-PTSD diagnosed veterans. In addition, the F-2-8 profile showed significantly higher elevations for veterans with PTSD who are survivors of MST compared to veterans with combat PTSD and veteran controls. However, when veterans with PTSD were split by gender, male survivors of MST showed significantly higher elevations on all three measures compared to male combat veterans, while there were no significant differences between MST and combat for females on any of the three measures. However, the large sample size in this study resulted in insignificant or small effect sizes, with the F-2-8 profile performing the best of all measures from an effect size perspective. This means the results of this study should be interpreted with caution, as they may not represent large differences in observed results for these groups and measures. Further areas for study and implications of these findings for treatment of veterans in the VA system are also explored

    Centering the Marginalized: The Impact of the Pandemic on Online Student Retention

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    During the pandemic, much of the focus of administrators and scholars has been on its impact on residential students and the sudden shift to online instruction. While justified, researchers have yet to focus on online students—who often represent marginalized communities in higher education—to ask whether they were impacted by factors related to the pandemic other than the modality shift. In this study, we examined how the first-year retention of online students was affected during the pandemic, and whether it differed from first-year residential students who transitioned online. We examined records of two student cohorts (Fall 2017 and Fall 2019) from a university to determine each cohort’s retention rate by modality. Holding other relevant factors constant, we found the COVID cohort of students were less likely to persist to the following Fall regardless of modality, although residential students were still much more likely to be retained overall. However, Black and Hispanic students were less likely to be retained across both modalities, and even Black residential students were more vulnerable to not returning than their White counterparts, suggesting that racial inequalities persist across learning modalities. We conclude by suggesting how one retention tool—financial aid—could be used to address the particular needs of online students to improve their retention

    End-functionalized glycopolymers as mimetics of chondroitin sulfate proteoglycans

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    Glycosaminoglycans are sulfated polysaccharides that play important roles in fundamental biological processes, such as cell division, viral invasion, cancer and neuroregeneration. The multivalent presentation of multiple glycosaminoglycan chains on proteoglycan scaffolds may profoundly influence their interactions with proteins and subsequent biological activity. However, the importance of this multivalent architecture remains largely unexplored, and few synthetic mimics exist for probing and manipulating glycosaminoglycan activity. Here, we describe a new class of end-functionalized ring-opening metathesis polymerization (ROMP) polymers that mimic the native-like, multivalent architecture found on chondroitin sulfate (CS) proteoglycans. We demonstrate that these glycopolymers can be readily integrated with microarray and surface plasmon resonance technology platforms, where they retain the ability to interact selectively with proteins. ROMP-based glycopolymers are part of a growing arsenal of chemical tools for probing the functions of glycosaminoglycans and for studying their interactions with proteins

    Power Wheelchair Canopy

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    Some power wheelchair users can not drive and independently hold an umbrella at the time because they do not have much upper body strength. Therefore, users are unprotected from the rain and are getting soaking wet. One of the members of this group is in a wheelchair and faces this problem. He has previously searched for something to protect him from rain, but could not found something he could independently use. What users need is a powered umbrella that attaches to their power wheelchair. There is no such umbrella available in the market. In this project, the solution to this problem will be designed and built in the form of an umbrella for his wheelchair. Exploration of various methods of rain protect will be explored. Calculations will be performed to verify that everything will work when assembled. The prototype will then be built. Assuming there will be some issues, as there always seem to be, several iterations of the prototype will be built. This is assuming that there will still be money left in the budget to complete these other iterations. It is also desired to make it inexpensive. This will allow power wheelchair users all over the world to purchase it for themselves. In order to achieve this, the project will lean heavily on the 3-D printing capabilities that the University of Akron has to offer

    Book Reviews

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    A History of Archival Practice. Paul Delsalle. Translated and revised by Margaret Procter. Archival Arrangement and Description: Analog to Digital. Lois Hamill. Participatory Heritage. Andrea Copeland and Henriette Roued-Cunliffe. Managing Local Government Archives. John H. Slate and Kaye Lanning Minchew. Archiving Websites: A Practical Guide for Information Management Professionals. Adrian Brown

    Transcriptome of the Caribbean stony coral Porites astreoides from three developmental stages

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    © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in GigaScience 5 (2016): 33, doi:10.1186/s13742-016-0138-1.Porites astreoides is a ubiquitous species of coral on modern Caribbean reefs that is resistant to increasing temperatures, overfishing, and other anthropogenic impacts that have threatened most other coral species. We assembled and annotated a transcriptome from this coral using Illumina sequences from three different developmental stages collected over several years: free-swimming larvae, newly settled larvae, and adults (>10 cm in diameter). This resource will aid understanding of coral calcification, larval settlement, and host–symbiont interactions. A de novo transcriptome for the P. astreoides holobiont (coral plus algal symbiont) was assembled using 594 Mbp of raw Illumina sequencing data generated from five age-specific cDNA libraries. The new transcriptome consists of 867 255 transcript elements with an average length of 685 bases. The isolated P. astreoides assembly consists of 129 718 transcript elements with an average length of 811 bases, and the isolated Symbiodinium sp. assembly had 186 177 transcript elements with an average length of 1105 bases. This contribution to coral transcriptome data provides a valuable resource for researchers studying the ontogeny of gene expression patterns within both the coral and its dinoflagellate symbiont.Bioinformatic analysis was performed in part on computing resources at the University of Puerto Rico (UPR) Puerto Rico Center for Environmental Neuroscience (PRCEN)’s High Performance Computing Facility, which is supported by: Institutional Development Award Networks of Biomedical Research Excellent (INBRE) grant P20GM103475 from the National Institute of General Medical Sciences, National Institutes of Health; the Institute for Functional Nanomaterials (IFN) award from the Experimental Program to Stimulate Competitive Research (EPSCoR) Track 1 program of the National Science Foundation (NSF); and EPSCoR Track 2 awards for computational nanoscience (EPS 1002410, EPS 1010094). Funding and support of the research was provided by PRCEN thanks to an NSF Centers of Research Excellent in Science and Technology (CREST) award, number HRD-1137725

    Design of University Small-Scale Dairy Processing Facility

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    This project was assigned to research the feasibility and value of implementing a dairy processing facility on the campus of the University of Nebraska-Lincoln. The facility would process milk produced from cows under the same roof and will serve as an educational experience for Nebraska dairy farmers, UNL students, and K-12 students in the Lincoln-Lancaster County area. If the project is successful and replicated across the state, this facility could have a significant impact on the reduction of milk transportation costs in the Nebraska dairy industry. The project began with researching milk processing methods and steps from production to consumption. Shortly after this step, information on milk consumption patterns was collected from UNL Dining Services to determine demand on campus. Every unit operation requires certain equipment to effectively ensure the safety and quality of the final product, and mass balances from UNL milk consumption data were used to size equipment and storage capacity. Engineering firms were then consulted to gather information on equipment specifications and prices. Equipment costs and operating costs (estimated with the help of Dr. Howell and other university dairy operations) were entered into a Monte Carlo simulation to analyze return on investment and a breakeven point. The results from the costs section showed that the fixed costs (equipment and engineering) for the milk processing would be about $1.2 million. The Monte Carlo simulation showed that the project would not turn a profit for 10-12 years, and approximately 2.25 million gallons of milk would need to be processed and sold to recover initial costs. Overall, the project successfully displays data that can be interpreted by the client to decide whether to move forward with the project and the appropriate scale for the project at UNL
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