1,213 research outputs found

    Infusing Humanities in STEM Education: Student Opinions of Disciplinary Connections in an Introductory Chemistry Course

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    The Next Generation Science Standards and other educational reforms support the formation of deep connections across the STEM disciplines. Integrated STEM is considered as a best practice by the educational communities of the disparate disciplines. However, the integration of non-STEM disciplines is understudied and generally limited to the integration of art (STEAM). Humanistic STEM blends the study of STEM with interest in and concern for human affairs, welfare, values, or culture. This study looks at an infusion of the humanities into an online chemistry course to see if there is an influence on student connection between course content and cross-disciplinary perspectives. Specifically, students were asked about the course making clear connection to STEM disciplines, between science and non-science, between science and the real world, and a widened perspective of science connection other courses in their degree programs. Items on a Likert scale were presented as part of the end of course evaluations and yielded 59 responses. Although no statistically significant difference in the pre-and post-infusion agreement, it is evident that the additional perspectives did no harm. The positive movement in this pilot study encourages further investigation with stronger infusions of both STEM and humanities content

    Percolating through networks of random thresholds: Finite temperature electron tunneling in metal nanocrystal arrays

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    We investigate how temperature affects transport through large networks of nonlinear conductances with distributed thresholds. In monolayers of weakly-coupled gold nanocrystals, quenched charge disorder produces a range of local thresholds for the onset of electron tunneling. Our measurements delineate two regimes separated by a cross-over temperature T∗T^*. Up to T∗T^* the nonlinear zero-temperature shape of the current-voltage curves survives, but with a threshold voltage for conduction that decreases linearly with temperature. Above T∗T^* the threshold vanishes and the low-bias conductance increases rapidly with temperature. We develop a model that accounts for these findings and predicts T∗T^*.Comment: 5 pages including 3 figures; replaced 3/30/04: minor changes; final versio

    A Comparison of Online, Video Synchronous, and Traditional Learning Modes for an Introductory Undergraduate Physics Course

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    While the equivalence between online and traditional classrooms has been well-researched, very little of this includes college-level introductory Physics. Only one study explored Physics at the whole-class level rather than specific course components such as a single lab or a homework platform. In this work, we compared the failure rate, grade distribution, and withdrawal rates in an introductory undergraduate Physics course across several learning modes including traditional face-to-face instruction, synchronous video instruction, and online classes. Statistically significant differences were found for student failure rates,grade distribution, and withdrawal rates but yielded small effect sizes. Post-hoc pair-wise test was run to determine differences between learning modes. Online students had a significantly lower failure rate than students who took the class via synchronous video classroom. While statistically significant differences were found for grade distributions, the pair-wise comparison yielded no statistically significance differences between learning modes when using the more conservative Bonferroni correction in post-hoc testing. Finally, in this study, student withdrawal rates were lowest for students who took the class in person (in-person classroom and synchronous video classroom) than online. Students that persist in an online introductory Physics class are more likely to achieve an A than in other modes. However, the withdrawal rate is higher from online Physics courses. Further research is warranted to better understand the reasons for higher withdrawal rates in online courses. Finding the root cause to help eliminate differences in student performance across learning modes should remain a high priority for education researchers and the education community as a whole

    A Comparison of Online and Traditional Chemistry Lecture and Lab

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    While the equivalence between online and traditional classrooms has been well researched, very little effort has been expended to do such comparisons for college level introductory chemistry. The existing literature has only one study that investigated chemistry lectures at an entire course level as opposed to particular course components such as individual topics or exams. Regarding lab courses, only one study is available and it involves moderating variables that are largely uncontrolled. In this work, we compared the student pass rates, withdrawal rates, and grade distributions between asynchronous online and traditional formats of an introductory chemistry lecture as well as its associated lab course. The study was based on the 823 university records available for the 2015–2016 academic year. Student pass and withdrawal rates between the two modes were quite similar and did not appear to be statistically significant. However, grade distributions for both the lecture and lab differed between the two learning modes, showing significant statistical associations. Online students were more likely to earn As in both lecture and lab while traditional in-person students were more likely to earn Cs or Ds. Further research should include replication of this study with a larger data set. Additionally, this study should be repeated in three to five years to determine if advances in course design, standardization and delivery platforms further reduce or eliminate differences between learning modes. Future studies should also use qualitative tools for a better understanding of why students fail or withdraw from courses

    New Algorithm for Mixmaster Dynamics

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    We present a new numerical algorithm for evolving the Mixmaster spacetimes. By using symplectic integration techniques to take advantage of the exact Taub solution for the scattering between asymptotic Kasner regimes, we evolve these spacetimes with higher accuracy using much larger time steps than previously possible. The longer Mixmaster evolution thus allowed enables detailed comparison with the Belinskii, Khalatnikov, Lifshitz (BKL) approximate Mixmaster dynamics. In particular, we show that errors between the BKL prediction and the measured parameters early in the simulation can be eliminated by relaxing the BKL assumptions to yield an improved map. The improved map has different predictions for vacuum Bianchi Type IX and magnetic Bianchi Type VI0_0 Mixmaster models which are clearly matched in the simulation.Comment: 12 pages, Revtex, 4 eps figure

    Atomic Hydrogen and Star Formation in the Bridge/Ring Interacting Galaxy Pair NGC 7714/7715 (Arp 284)

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    We present high spatial resolution 21 cm HI maps of the interacting galaxy pair NGC 7714/7715. We detect a massive (2 x 10**9 M(sun)) HI bridge connecting the galaxies that is parallel to but offset from the stellar bridge. A chain of HII regions traces the gaseous bridge, with H-alpha peaks near but not on the HI maxima. An HI tidal tail is also detected to the east of the smaller galaxy NGC 7715, similarly offset from a stellar tail. The strong partial stellar ring on the eastern side of NGC 7714 has no HI counterpart, but on the opposite side of NGC 7714 there is a 10**9 M(sun) HI loop 11 kpc in radius. Within the NGC 7714 disk, clumpy HI gas is observed associated with star formation regions. Redshifted HI absorption is detected towards the starburst nucleus. We compare the observed morphology and gas kinematics with gas dynamical models in which a low-mass companion has an off-center prograde collision with the outer disk of a larger galaxy. These simulations suggest that the bridge in NGC 7714/7715 is a hybrid between bridges seen in systems like M51 and the purely gaseous `splash' bridges found in ring galaxies like the Cartwheel. The offset between the stars and gas in the bridge may be due to dissipative cloud-cloud collisions occuring during the impact of the two gaseous disks.Comment: 31 pages, Latex, 11 figures, to be published in the July 10, 1997 issue of the Astrophysical Journa

    FGF4 retrogene on CFA12 is responsible for chondrodystrophy and intervertebral disc disease in dogs.

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    Chondrodystrophy in dogs is defined by dysplastic, shortened long bones and premature degeneration and calcification of intervertebral discs. Independent genome-wide association analyses for skeletal dysplasia (short limbs) within a single breed (PBonferroni = 0.01) and intervertebral disc disease (IVDD) across breeds (PBonferroni = 4.0 × 10-10) both identified a significant association to the same region on CFA12. Whole genome sequencing identified a highly expressed FGF4 retrogene within this shared region. The FGF4 retrogene segregated with limb length and had an odds ratio of 51.23 (95% CI = 46.69, 56.20) for IVDD. Long bone length in dogs is a unique example of multiple disease-causing retrocopies of the same parental gene in a mammalian species. FGF signaling abnormalities have been associated with skeletal dysplasia in humans, and our findings present opportunities for both selective elimination of a medically and financially devastating disease in dogs and further understanding of the ever-growing complexity of retrogene biology

    Hunting Local Mixmaster Dynamics in Spatially Inhomogeneous Cosmologies

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    Heuristic arguments and numerical simulations support the Belinskii et al (BKL) claim that the approach to the singularity in generic gravitational collapse is characterized by local Mixmaster dynamics (LMD). Here, one way to identify LMD in collapsing spatially inhomogeneous cosmologies is explored. By writing the metric of one spacetime in the standard variables of another, signatures for LMD may be found. Such signatures for the dynamics of spatially homogeneous Mixmaster models in the variables of U(1)-symmetric cosmologies are reviewed. Similar constructions for U(1)-symmetric spacetimes in terms of the dynamics of generic T2T^2-symmetric spacetime are presented.Comment: 17 pages, 5 figures. Contribution to CQG Special Issue "A Spacetime Safari: Essays in Honour of Vincent Moncrief

    Mixmaster Behavior in Inhomogeneous Cosmological Spacetimes

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    Numerical investigation of a class of inhomogeneous cosmological spacetimes shows evidence that at a generic point in space the evolution toward the initial singularity is asymptotically that of a spatially homogeneous spacetime with Mixmaster behavior. This supports a long-standing conjecture due to Belinskii et al. on the nature of the generic singularity in Einstein's equations.Comment: 4 pages plus 4 figures. A sentence has been deleted. Accepted for publication in PR

    Antenatal steroid exposure and heart rate variability in adolescents born with very low birth weight

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    Reduced heart rate variability (HRV) suggests autonomic imbalance in the control of heart rate and is associated with unfavorable cardiometabolic outcomes. We examined whether antenatal corticosteroid (ANCS) exposure had long-term programming effects on heart rate variability (HRV) in adolescents born with very low birth weight (VLBW)
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