335 research outputs found
PassNote: A Feedback Tool for Improving Student Success Outcomes
When Purdue University faculty asked for assistance in composing feedback messages to students, Information Technology at Purdue (ITaP) developed PassNote, a feedback tool that integrates good practice into the process of providing formative assessments. PassNote gives faculty customizable feedback prompts (snippets) and lets them connect students with information and links to services such as tutoring,Supplemental Instruction, library resources, technology tools, and workshops. PassNote message starters are often incomplete, allowing instructors to include course-specific information such as office hours and departmental resources
Predicting academic success in optometry school
Introduction: Predicting success in optometry school is a challenging task which involves evaluating many academic and non-academic qualities. This study aids in the process of selecting candidates who are likely to be successful in the challenging optometric curriculum.
Methods: Optometry Admission Test (OAT) scores, interview scores, and undergraduate and optometry grade point averages (GPA) were gathered for 175 students admitted to Pacific University College of Optometry in 2001 and 2002. At-test compared characteristics of students who failed at least one didactic course in optometry school with students who passed all optometry courses. Regression analysis was then used to establish equations to predict academic performance.
Results and Discussion: All undergraduate GPA variables and most OAT subsections demonstrated a significant difference between students who failed an optometry course and those who did not. Reading Comprehension OAT, Physics OAT, and the interview score did not demonstrate a statistically significant difference between the two groups. Three equations were developed to help predict GPA in optometry school and to predict the probability of a student failing an optometric course.
Conclusion: The equations discussed can be used by admission committees as one tool to help in the application process and to predict success prior to admitting optometlic students
The Submillimeter Bump in Sgr A* from Relativistic MHD Simulations
Recent high resolution observations of the Galactic center black hole allow
for direct comparison with accretion disk simulations. We compare
two-temperature synchrotron emission models from three dimensional, general
relativistic magnetohydrodynamic simulations to millimeter observations of Sgr
A*. Fits to very long baseline interferometry and spectral index measurements
disfavor the monochromatic face-on black hole shadow models from our previous
work. Inclination angles \le 20 degrees are ruled out to 3 \sigma. We estimate
the inclination and position angles of the black hole, as well as the electron
temperature of the accretion flow and the accretion rate, to be i=50+35-15
degrees, \xi=-23+97-22 degrees, T_e=(5.4 +/- 3.0)x10^10 K and
Mdot=(5+15-2)x10^-9 M_sun / yr respectively, with 90% confidence. The black
hole shadow is unobscured in all best fit models, and may be detected by
observations on baselines between Chile and California, Arizona or Mexico at
1.3mm or .87mm either through direct sampling of the visibility amplitude or
using closure phase information. Millimeter flaring behavior consistent with
the observations is present in all viable models, and is caused by magnetic
turbulence in the inner radii of the accretion flow. The variability at
optically thin frequencies is strongly correlated with that in the accretion
rate. The simulations provide a universal picture of the 1.3mm emission region
as a small region near the midplane in the inner radii of the accretion flow,
which is roughly isothermal and has \nu/\nu_c ~ 1-20, where \nu_c is the
critical frequency for thermal synchrotron emission.Comment: 14 pages, 17 figures, accepted by Ap
FINIS: New Methane Detector Technology for Point-Source Detection and Leak Rate Measurements
Utah State University has been developing the Filter Incidence Narrow-band Infrared Spectrometer (FINIS) as a compact instrument for observing atmospheric methane from CubeSats. This instrument will be tested on the upcoming ACMES mission for use as a methane detector. The ACMES mission was selected in 2021 as part of the NASA In-space Validation of Earth Science Technologies (InVEST) program with an expected launch in 2024. Methane is the second most important greenhouse gas and one for which a reduction in emissions could have a significant impact on the near-term rate of global warming. As part of the effort to measure tropospheric methane concentration from space, point source leaks have shown to be challenging to be detected and measured using historic satellite sensors due to their low spatial resolution. In this context, Utah State University has been developing FINIS to be suitable for CH4 leak detection using the differential absorption technique in the 1.6 um band of methane. This paper presents the FINIS design for ACMES, including the instrument review, the concept of operation along with lessons learned from previous air-based testing of the FINIS prototype
230 GHz VLBI OBSERVATIONS OF M87: EVENT‐HORIZON‐SCALE STRUCTURE DURING AN ENHANCED VERY‐HIGH‐ENERGY γ‐RAY STATE IN 2012
We report on 230 GHz (1.3 mm) very long baseline interferometry (VLBI) observations of M87 with the Event Horizon Telescope using antennas on Mauna Kea in Hawaii, Mt. Graham in Arizona, and Cedar Flat in California. For the first time, we have acquired 230 GHz VLBI interferometric phase information on M87 through measurement of the closure phase on the triangle of long baselines. Most of the measured closure phases are consistent with 0° as expected by physically motivated models for 230 GHz structure such as jet models and accretion disk models. The brightness temperature of the event-horizon-scale structure is ~1 X 10[superscript 10] K derived from the compact flux density of ~1 Jy and the angular size of ~40 µas ~ 5.5 R[subscript s], which is broadly consistent with the peak brightness of the radio cores at 1–86 GHz located within ~10[superscript 2] R[subscript s]. Our observations occurred in the middle of an enhancement in very-high-energy (VHE) γ-ray flux, presumably originating in the vicinity of the central black hole. Our measurements, combined with results of multi-wavelength observations, favor a scenario in which the VHE region has an extended size of ~20–60 R[subscript s]
Recommended Revisions to the National SEP‐1 Sepsis Quality Measure: A commentary by the Society of Infectious Diseases Pharmacists on the Infectious Diseases Society of America Position Paper
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154912/1/phar2384.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154912/2/phar2384_am.pd
Superresolution Full-polarimetric Imaging for Radio Interferometry with Sparse Modeling
We propose a new technique for radio interferometry to obtain superresolution full-polarization images in all four Stokes parameters using sparse modeling. The proposed technique reconstructs the image in each Stokes parameter from the corresponding full-complex Stokes visibilities by utilizing two regularization functions: the ℓ 1 norm and the total variation (TV) of the brightness distribution. As an application of this technique, we present simulated linear polarization observations of two physically motivated models of M87 with the Event Horizon Telescope. We confirm that ℓ 1+TV regularization can achieve an optimal resolution of ~25%–30% of the diffraction limit λ/D[subscript max], which is the nominal spatial resolution of a radio interferometer for both the total intensity (i.e., Stokes I) and linear polarizations (i.e., Stokes Q and U). This optimal resolution is better than that obtained from the widely used Cotton–Schwab CLEAN algorithm or from using ℓ 1 or TV regularizations alone. Furthermore, we find that ℓ 1+TV regularization can achieve much better image fidelity in linear polarization than other techniques over a wide range of spatial scales, not only in the superresolution regime, but also on scales larger than the diffraction limit. Our results clearly demonstrate that sparse reconstruction is a useful choice for high-fidelity full-polarimetric interferometric imaging
Tilted black hole accretion disc models of Sagittarius A*: time-variable millimetre to near-infrared emission
High-resolution, multi-wavelength, and time-domain observations of the
Galactic centre black hole candidate, Sgr A*, allow for a direct test of
contemporary accretion theory. To date, all models have assumed alignment
between the accretion disc and black hole angular momentum axes, but this is
unjustified for geometrically thick accretion flows like that onto Sgr A*.
Instead, we calculate images and spectra from a set of simulations of accretion
flows misaligned ('tilted') by 15 degrees from the black hole spin axis and
compare them with millimetre (mm) to near-infrared (NIR) observations.
Non-axisymmetric standing shocks from eccentric fluid orbits dominate the
emission, leading to a wide range of possible image morphologies. These effects
invalidate previous parameter estimates from model fitting, including estimates
of the dimensionless black hole spin, except possibly at low values of spin or
tilt. At 1.3mm, the images have crescent morphologies, and the black hole
shadow may still be accessible to future mm-VLBI observations. Shock heating
leads to high energy electrons (T > 10^12 K), which can naturally produce the
observed NIR flux, spectral index, and rapid variability ('flaring'). This NIR
emission is uncorrelated with that in the mm, which also agrees with
observations.
These are the first models to self-consistently explain the time-variable mm
to NIR emission of Sgr A*. Predictions of the model include significant
structural changes observable with mm-VLBI on both the dynamical (hour) and
Lense-Thirring precession (day-year) timescales; and ~30-50 microarcsecond
changes in centroid position from extreme gravitational lensing events during
NIR flares, detectable with the future VLT instrument GRAVITY. If the observed
NIR emission is caused by shock heating in a tilted accretion disc, then the
Galactic centre black hole has a positive, non-zero spin parameter (a > 0).Comment: 17 pages, 18 figures, submitted to MNRAS; for movies and version with
high-res figures see http://astro.berkeley.edu/~jdexter/tiltedsgr
MicroRNA Regulation of Cell Lineages in Mouse and Human Embryonic Stem Cells
SummaryCell fate decisions of pluripotent embryonic stem (ES) cells are dictated by activation and repression of lineage-specific genes. Numerous signaling and transcriptional networks progressively narrow and specify the potential of ES cells. Whether specific microRNAs help refine and limit gene expression and, thereby, could be used to manipulate ES cell differentiation has largely been unexplored. Here, we show that two serum response factor (SRF)-dependent muscle-specific microRNAs, miR-1 and miR-133, promote mesoderm formation from ES cells but have opposing functions during further differentiation into cardiac muscle progenitors. Furthermore, miR-1 and miR-133 were potent repressors of nonmuscle gene expression and cell fate during mouse and human ES cell differentiation. miR-1's effects were in part mediated by translational repression of the Notch ligand Delta-like 1 (Dll-1). Our findings indicate that muscle-specific miRNAs reinforce the silencing of nonmuscle genes during cell lineage commitment and suggest that miRNAs may have general utility in regulating cell-fate decisions from pluripotent ES cells
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