575 research outputs found
Computer Literacy: Implications for Teaching a College-Level Course
The purpose of this study was to investigate students’ perceptions of computer literacy skills they had obtained prior to enrolling in a university and to develop implications and recommendations for teaching a college-level computer course. One hundred twenty-five students who were currently enrolled in a required university computer literacy course completed a questionnaire. Students were asked to identify their skill level in various types of software and their exposure to computer concepts and issues. Results showed that students perceived themselves to be better prepared in word processing than they did in spreadsheet and database applications and that they had not received extensive coverage of ethical, social, legal and global issues. In determining the content of a university computer literacy course, consideration needs to be given to nontraditional students who have not been exposed to computers as well as those students who enter the university with a variety of skill levels. Additionally, an improved and extended coverage of database and spreadsheets might be warranted in a college level computer course. Since required computer literacy competencies are continually changing for high school graduates, it is imperative that universities monitor design and content of the curriculum to provide an adequate computer literacy background for university students
Extraosseous Osteosarcoma of the Esophagus: A Case Report
Extraosseous osteosarcoma (EOO) is a malignant mesenchymal neoplasm that is located in the soft tissues without direct attachment to the skeletal system and that produces osteoid, bone, or chondroid material. EOO is an extremely rare disease, accounting for only 1% of soft tissue sarcomas, and typically presents in either an extremity or the retroperitoneum. This paper presents the case of a 45-year-old Caucasian male with extraosseous osteosarcoma of the esophagus
Olfactory ensheathing glia are required for embryonic olfactory axon targeting and the migration of gonadotropin-releasing hormone neurons.
Kallmann's syndrome is caused by the failure of olfactory axons and gonadotropin-releasing hormone (GnRH) neurons to enter the embryonic forebrain, resulting in anosmia and sterility. Sox10 mutations have been associated with Kallmann's syndrome phenotypes, but their effect on olfactory system development is unknown. We recently showed that Sox10 is expressed by neural crest-derived olfactory ensheathing cells (OECs). Here, we demonstrate that in homozygous Sox10(lacZ/lacZ) mouse embryos, OEC differentiation is disrupted; olfactory axons accumulate in the ventromedial olfactory nerve layer and fewer olfactory receptor neurons express the maturation marker OMP (most likely owing to the failure of axonal targeting). Furthermore, GnRH neurons clump together in the periphery and a smaller proportion enters the forebrain. Our data suggest that human Sox10 mutations cause Kallmann's syndrome by disrupting the differentiation of OECs, which promote embryonic olfactory axon targeting and hence olfactory receptor neuron maturation, and GnRH neuron migration to the forebrain.This work was supported by the Wellcome Trust [grant 091555 to C.V.H.B. and P.B.], a Griffith University Encouragement Research grant to J.A.S., and Deutsche Forschungsgemeinschaft [grant We1326/9 to M.W.].This is the final version of the article. It was first available from The Company of Biologists via http://dx.doi.org/10.1242/bio.2013524
An estimate of \Omega_m without priors
Using mean relative peculiar velocity measurements for pairs of galaxies, we
estimate the cosmological density parameter and the amplitude of
density fluctuations . Our results suggest that our statistic is a
robust and reproducible measure of the mean pairwise velocity and thereby the
parameter. We get and . These estimates do not depend on prior assumptions on
the adiabaticity of the initial density fluctuations, the ionization history,
or the values of other cosmological parameters.Comment: 12 pages, 4 figures, slight changes to reflect published versio
Self-Serving Bias in Performance Goal Achievement Appraisals: Evidence From Long-Distance Runners
While working with a long-distance running event organizer, the authors of this study observed considerable differences between event participants’ official finish time (i.e., bib time) and their self-reported finish time in the post-event survey. Drawing on the notion of self-serving bias, we aim to explore the source of this disparity and how such psychological bias influences participants’ event experience at long-distance running events. Using evidence of 1,320 marathon runners, we demonstrated how people are more likely to be subject to a biased self-assessment contingent upon achieving their best finish time at the event. The study samples were split into record-high-achieved and record-high-missed groups, and the self-serving biases of each group were explored. Results from the t-test comparing record-high-achieved and -missed groups showed that runners in the record-high-missed group were significantly more likely to report a positively biased finish time than runners in the record-high-achieved group (p \u3c 0.01). Additionally, results from logistic regression showed that as runners missed their best finish time by a wider margin, the probability of reporting a positively biased incorrect finish time increased. Lastly, we conducted an additional t-test and revealed that runners who are subject to self-serving bias showed a lower level of overall event satisfaction. The current study suggests one way to bypass the adverse effects of participant sport event participants’ worse-than-expected athletic performance. We specifically suggest that the event organizers target runners who had worse-than-expected performance and make extra efforts on non-race service attributes (e.g., finish line experience, rest and recovery area, and transportation after the event) because these runners are more likely to be unsatisfied with the event
UV Observations of the Cool DBQA5 White Dwarf LDS 678A - Limits on the Atmospheric Composition, Pressure Shift, and Gravitational Redshift Derived from C I 2479
A high-resolution ultraviolet spectrum of the helium-rich degenerate LDS 678A, obtained with the International Ultraviolet Explorer (IUE) satellite, is presented. LDS 678A is the coolest metallic line degenerate (DQ or DZ) yet observed with the IUE echelle. These observations provide a detailed line profile of the strong C I 2479 absorption line and equivalent width W2479 = 2.35 + or - 0.06 A from which theoretical profile fits yield a carbon abundance of log C/He = (-6.7 + or- 0.2). The presence of carbon in a He-rich atmosphere lends credence to the notion that LDS 678A is a transitional case between the DB white dwarfs with nearly pure helium atmospheres and the helium-rich DQ white dwarfs which exhibit carbon bands. Corrected for an inferred pressure shift Vp = + 38 + or - 4 km/s for the C I 2479 line, a gravitational redshift of Vrs = + 26 + or - 13 km/s is deduced from which a most probable mass of 0.55 solar mass is derived
The Formation Rate, Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey
Spectrophotometric observations at high signal-to-noise ratio were obtained
of a complete sample of 347 DA white dwarfs from the Palomar Green (PG) Survey.
Fits of observed Balmer lines to synthetic spectra calculated from
pure-hydrogen model atmospheres were used to obtain robust values of Teff, log
g, masses, radii, and cooling ages. The luminosity function of the sample,
weighted by 1/Vmax, was obtained and compared with other determinations. The
mass distribution of the white dwarfs is derived, after important corrections
for the radii of the white dwarfs in this magnitude-limited survey and for the
cooling time scales. The formation rate of DA white dwarfs from the PG is
estimated to be 0.6x10^(-12) pc^(-3) yr^(-1). Comparison with predictions from
a theoretical study of the white dwarf formation rate for single stars
indicates that >80% of the high mass component requires a different origin,
presumably mergers of lower mass double degenerate stars. In order to estimate
the recent formation rate of all white dwarfs in the local Galactic disk,
corrections for incompleteness of the PG, addition of the DB-DO white dwarfs,
and allowance for stars hidden by luminous binary companions had to be applied
to enhance the rate. An overall formation rate of white dwarfs recently in the
local Galactic disk of 1.15+/-0.25x10^(-12) pc^(-3) yr^(-1) is obtained. Two
recent studies of samples of nearby Galactic planetary nebulae lead to
estimates around twice as high. Difficulties in reconciling these
determinations are discussed.Comment: 73 pages, 18 figures, accepted for publication in the ApJ Supplemen
High gradient testing of an X-band crab cavity at XBOX2
CERN’s Compact linear collider (CLIC) will require crab cavities to align the bunches to provide effective head-on collisions. An X-band quasi-TM11 deflecting cavity has been designed and manufactured for testing at CERN’s Xbox-2 high power standalone test stand. The cavity is currently under test and has reached an input power level in excess of 40MW, with a measured breakdown rate of better than 10-5 breakdowns per pulse. This paper also describes surface field quantities which are important in assessing the expected BDR when designing high gradient structures
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