4,656 research outputs found
Scientific reasoning abilities of non-science majors in physics-based courses
We have found that non-STEM majors taking either a conceptual physics or
astronomy course at two regional comprehensive institutions score significantly
lower pre-instruction on the Lawson's Classroom Test of Scientific Reasoning
(LCTSR) in comparison to national average STEM majors. The majority of non-STEM
students can be classified as either concrete operational or transitional
reasoners in Piaget's theory of cognitive development, whereas in the STEM
population formal operational reasoners are far more prevalent. In particular,
non-STEM students demonstrate significant difficulty with proportional and
hypothetico-deductive reasoning. Pre-scores on the LCTSR are correlated with
normalized learning gains on various concept inventories. The correlation is
strongest for content that can be categorized as mostly theoretical, meaning a
lack of directly observable exemplars, and weakest for content categorized as
mostly descriptive, where directly observable exemplars are abundant. Although
the implementation of research-verified, interactive engagement pedagogy can
lead to gains in content knowledge, significant gains in theoretical content
(such as force and energy) are more difficult with non-STEM students. We also
observe no significant gains on the LCTSR without explicit instruction in
scientific reasoning patterns. These results further demonstrate that
differences in student populations are important when comparing normalized
gains on concept inventories, and the achievement of significant gains in
scientific reasoning requires a re-evaluation of the traditional approach to
physics for non-STEM students.Comment: 18 pages, 4 figures, 3 table
The Symmetric Group Defies Strong Fourier Sampling
The dramatic exponential speedups of quantum algorithms over their best existing classical counterparts were ushered in by the technique of Fourier sampling, introduced by Bernstein and Vazirani and developed by Simon and Shor into an approach to the hidden subgroup problem. This approach has proved successful for abelian groups, leading to efficient algorithms for factoring, extracting discrete logarithms, and other number-theoretic problems. We show, however, that this method cannot resolve the hidden subgroup problem in the symmetric groups, even in the weakest, information-theoretic sense. In particular, we show that the Graph Isomorphism problem cannot be solved by this approach. Our work implies that any quantum approach based upon the measurement of coset states must depart from the original framework by using entangled measurements on multiple coset states
Are stellar-mass black-hole binaries too quiet for LISA?
The progenitors of the high-mass black-hole mergers observed by LIGO and
Virgo are potential LISA sources and promising candidates for multiband GW
observations. In this letter, we consider the minimum signal-to-noise ratio
these sources must have to be detected by LISA. Our revised threshold of
is higher than previous estimates, which significantly
reduces the expected number of events. We also point out the importance of the
detector performance at high-frequencies and the duration of the LISA mission,
which both influence the event rate substantially.Comment: 6 pages, 3 figures. Published in MNRAS letters. DOI
10.1093/mnrasl/slz10
Frequency-domain waveform approximants capturing Doppler shifts
Gravitational wave astrophysics has only just begun, and as current detectors
are upgraded and new detectors are built, many new, albeit faint, features in
the signals will become accessible. One such feature is the presence of
time-dependent Doppler shifts, generated by the acceleration of the center of
mass of the gravitational-wave emitting system. We here develop a generic
method that takes a frequency-domain, gravitational-wave model devoid of
Doppler shifts and introduces modifications that incorporate them. Building
upon a perturbative expansion that assumes the Doppler-shift velocity is small
relative to the speed of light, the method consists of the inclusion of a
single term in the Fourier phase and two terms in the Fourier amplitude. We
validate the method through matches between waveforms with a Doppler shift in
the time domain and waveforms constructed with our method for two toy problems:
constant accelerations induced by a distant third body and Gaussian
accelerations that resemble a kick profile. We find mismatches below
for all of the astrophysically relevant cases considered, and
improve further at smaller velocities. The work presented here will allow for
the use of future detectors to extract new, faint features in the signal from
the noise.Comment: 11 pages, 5 figures, submitted to Phys. Rev.
Sense-making across disciplines : physical models, theoretical frameworks, and the connections between education in the humanities and sciences
Across disciplines, the fundamental goal of authentic learning is sense-making:
making sense of the world around us, our interactions, and art. As education shifts from
a discipline focused on propagating knowledge as ‘stuff’ to a focus on propagating
understanding and teaching the means towards understanding, the learning of sensemaking
practice across the disciplines is becoming more important. In the recent past,
education at nearly all levels has focused on the teaching of facts. The practices of
experts within disciplines were taught rarely, if at all, and almost exclusively at the level of
domain-specific skills. However, sense-making practices are surprisingly universal, and
not just across the sciences. In this paper, I discuss the parallels between the sciences
and humanities with respect to the practice of sense-making, specifically the mental/
physical models in the sciences and the theoretical frameworks deployed in the social
sciences and the humanities. I will make the case that we should begin addressing in our
classrooms the cross-cutting nature of the practices of all learners, so that students can
see how what they are doing when analysing history is not epistemologically dissimilar
to their physics class.peer-reviewe
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