1,064 research outputs found
Blogging in the physics classroom: A research-based approach to shaping students' attitudes towards physics
Even though there has been a tremendous amount of research done in how to
help students learn physics, students are still coming away missing a crucial
piece of the puzzle: why bother with physics? Students learn fundamental laws
and how to calculate, but come out of a general physics course without a deep
understanding of how physics has transformed the world around them. In other
words, they get the "how" but not the "why". Studies have shown that students
leave introductory physics courses almost universally with decreased
expectations and with a more negative attitude. This paper will detail an
experiment to address this problem: a course weblog or "blog" which discusses
real-world applications of physics and engages students in discussion and
thinking outside of class. Specifically, students' attitudes towards the value
of physics and its applicability to the real-world were probed using a
26-question Likert scale survey over the course of four semesters in an
introductory physics course at a comprehensive Jesuit university. We found that
students who did not participate in the blog study generally exhibited a
deterioration in attitude towards physics as seen previously. However, students
who read, commented, and were involved with the blog maintained their initially
positive attitudes towards physics. Student response to the blog was
overwhelmingly positive, with students claiming that the blog made the things
we studied in the classroom come alive for them and seem much more relevant.Comment: 20 pages, 6 figure
Time Delay Predictions in a Modified Gravity Theory
The time delay effect for planets and spacecraft is obtained from a fully
relativistic modified gravity theory including a fifth force skew symmetric
field by fitting to the Pioneer 10/11 anomalous acceleration data. A possible
detection of the predicted time delay corrections to general relativity for the
outer planets and future spacecraft missions is considered. The time delay
correction to GR predicted by the modified gravity is consistent with the
observational limit of the Doppler tracking measurement reported by the Cassini
spacecraft on its way to Saturn, and the correction increases to a value that
could be measured for a spacecraft approaching Neptune and Pluto.Comment: 5 pages, LaTex file, no figures. Corrections to Table
Electronic Event–based Surveillance for Monitoring Dengue, Latin America
Dengue, a potentially fatal disease, is spreading around the world. An estimated 2.5 billion people in tropical and subtropical regions are at risk. Early detection of outbreaks is crucial to prevention and control of dengue virus and other viruses. Case reporting may often take weeks or months. Therefore, researchers explored whether electronic sources of real-time information (such as Internet news outlets, health expert mailing lists, social media sites, and queries to online search engines) might be faster, and they were. Although information from unofficial sources should be interpreted with caution, when used in conjunction with traditional case reporting, real-time electronic surveillance can help public health authorities allocate resources in time to avert full-blown epidemics
Measuring the impact of health policies using Internet search patterns: the case of abortion
<p>Abstract</p> <p>Background</p> <p>Internet search patterns have emerged as a novel data source for monitoring infectious disease trends. We propose that these data can also be used more broadly to study the impact of health policies across different regions in a more efficient and timely manner.</p> <p>Methods</p> <p>As a test use case, we studied the relationships between abortion-related search volume, local abortion rates, and local abortion policies available for study.</p> <p>Results</p> <p>Our initial integrative analysis found that, both in the US and internationally, the volume of Internet searches for abortion is inversely proportional to local abortion rates and directly proportional to local restrictions on abortion.</p> <p>Conclusion</p> <p>These findings are consistent with published evidence that local restrictions on abortion lead individuals to seek abortion services outside of their area. Further validation of these methods has the potential to produce a timely, complementary data source for studying the effects of health policies.</p
Gravitational solution to the Pioneer 10/11 anomaly
A fully relativistic modified gravitational theory including a fifth force
skew symmetric field is fitted to the Pioneer 10/11 anomalous acceleration. The
theory allows for a variation with distance scales of the gravitational
constant G, the fifth force skew symmetric field coupling strength omega and
the mass of the skew symmetric field mu=1/lambda. A fit to the available
anomalous acceleration data for the Pioneer 10/11 spacecraft is obtained for a
phenomenological representation of the "running" constants and values of the
associated parameters are shown to exist that are consistent with fifth force
experimental bounds. The fit to the acceleration data is consistent with all
current satellite, laser ranging and observations for the inner planets.Comment: 14 pages, 3 figures, 3 tables. typo's were corrected at Equations (4)
and (12) and a third table including our predictions for the anomalous
perihelion advance of the planets was adde
Coexistence of Several Putative Neurotransmitters in Single Identified Neurosn of Aplysia
Ecotones as indicators: boundary properties in wetland-woodland transition zones
Ecotones, representing the transition zones between species or communities, have been suggested as focal points for detecting early shifts in vegetation composition due to anthropogenic impact. Here we examined if changes in ecotone location or properties can be used as reliable indicators of hydrological change in temperate wetland communities. We examined 38 woodland-wetland-woodland transitions, distributed across four sites with different anthropogenic disturbance histories and hydrological traits. We tested whether: 1) the ecotones are associated with environmental gradients, and 2) the location or properties of these ecotones change with disturbance history. Well-defined ecotones were associated with steep gradients in soil depth and soil moisture. Most ecotones showed a change in vegetation from hydrophytic to dryland species. There was also some evidence that in highly disturbed sites the link between ecotones and environmental gradients was less apparent. By sampling across boundaries we can better understand the factors controlling the distribution of species. This allows us to make better predictions about the impacts of anthropogenic change in wetland communities. By investigating the transitions between different vegetation communities we were able to highlight key indicators that could be used to monitor these ecologically sensitive and diverse wetland communities
Supersymmetry in quantum mechanics: An extended view
The concept of supersymmetry in a quantum mechanical system is extended,
permitting the recognition of many more supersymmetric systems, including very
familiar ones such as the free particle. Its spectrum is shown to be
supersymmetric, with space-time symmetries used for the explicit construction.
No fermionic or Grassmann variables need to be invoked. Our construction
extends supersymmetry to continuous spectra. Most notably, while the free
particle in one dimension has generally been regarded as having a doubly
degenerate continuum throughout, the construction clarifies taht there is a
single zero energy state at the base of the spectrum.Comment: 4 pages, 4 figure
The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Angular clustering tomography and its cosmological implications
We investigate the cosmological implications of studying galaxy clustering
using a tomographic approach applied to the final BOSS DR12 galaxy sample,
including both auto- and cross-correlation functions between redshift shells.
We model the signal of the full shape of the angular correlation function,
, in redshift bins using state-of-the-art modelling of
non-linearities, bias and redshift-space distortions. We present results on the
redshift evolution of the linear bias of BOSS galaxies, which cannot be
obtained with traditional methods for galaxy-clustering analysis. We also
obtain constraints on cosmological parameters, combining this tomographic
analysis with measurements of the cosmic microwave background (CMB) and type Ia
supernova (SNIa). We explore a number of cosmological models, including the
standard CDM model and its most interesting extensions, such as
deviations from w_\rm{DE} = -1, non-minimal neutrino masses, spatial
curvature and deviations from general relativity using the growth-index
parametrisation. These results are, in general, comparable to the most
precise present-day constraints on cosmological parameters, and show very good
agreement with the standard model. In particular, combining CMB,
and SNIa, we find a value of w_\rm{DE} consistent with
to a precision better than 5\% when it is assumed to be constant in time, and
better than 6\% when we also allow for a spatially-curved Universe.Comment: 21 pages, 18 figures, accepted for publication MNRAS. The data used
in this analysis is publicly available at
https://sdss3.org/science/boss_publications.ph
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