2,407 research outputs found
Learning analytics beyond the LMS: The connected learning analytics toolkit
We present a Connected Learning Analytics (CLA) toolkit, which enables data to be extracted from social media and imported into a Learning Record Store (LRS), as defined by the new xAPI standard. A number of implementation issues are discussed, and a mapping that will enable the consistent storage and then analysis of xAPI verb/object/activity statements across different social media and online environments is introduced. A set of example learning activities are proposed, each facilitated by the Learning Analytics beyond the LMS that the toolkit enables
New limits on cosmic strings from gravitational wave observation
We combine new analysis of the stochastic gravitational wave background to be
expected from cosmic strings with the latest pulsar timing array (PTA) limits
to give an upper bound on the energy scale of the possible cosmic string
network, at the 95% confidence level. We also show
bounds from LIGO and to be expected from LISA and BBO.
Current estimates for the gravitational wave background from supermassive
black hole binaries are at the level where a PTA detection is expected. But if
PTAs do observe a background soon, it will be difficult in the short term to
distinguish black holes from cosmic strings as the source, because the spectral
indices from the two sources happen to be quite similar.
If PTAs do not observe a background, then the limits on will improve
somewhat, but a string network with substantially below will
produce gravitational waves primarily at frequencies too high for PTA
observation, so significant further progress will depend on
intermediate-frequency observatories such as LISA, DECIGO and BBO.Comment: 9 pages, updated link to companion pape
Dermatoglyphic Traits of Jewish and Non-Jewish Whites
Author Institution: University of Toledo, Toledo 6, Ohi
Thomas-Fermi Approximation for a Condensate with Higher-order Interactions
We consider the ground state of a harmonically trapped Bose-Einstein
condensate within the Gross-Pitaevskii theory including the effective-range
corrections for a two-body zero-range potential. The resulting non-linear
Schr\"odinger equation is solved analytically in the Thomas-Fermi approximation
neglecting the kinetic energy term. We present results for the chemical
potential and the condensate profiles, discuss boundary conditions, and compare
to the usual Thomas-Fermi approach. We discuss several ways to increase the
influence of effective-range corrections in experiment with magnetically
tunable interactions. The level of tuning required could be inside experimental
reach in the near future.Comment: 8 pages, RevTex4 format, 5 figure
Reconciling threshold and subthreshold expansions for pion-nucleon scattering
Heavy-baryon chiral perturbation theory (ChPT) at one loop fails in relating
the pion-nucleon amplitude in the physical region and for subthreshold
kinematics due to loop effects enhanced by large low-energy constants. Studying
the chiral convergence of threshold and subthreshold parameters up to fourth
order in the small-scale expansion, we address the question to what extent this
tension can be mitigated by including the as an explicit degree
of freedom and/or using a covariant formulation of baryon ChPT. We find that
the inclusion of the indeed reduces the low-energy constants to more
natural values and thereby improves consistency between threshold and
subthreshold kinematics. In addition, even in the -less theory the
resummation of corrections in the covariant scheme improves the results
markedly over the heavy-baryon formulation, in line with previous observations
in the single-baryon sector of ChPT that so far have evaded a profound
theoretical explanation.Comment: 10 pages, 4 tables, Mathematica notebook with the analytic
expressions for threshold and subthreshold parameters included as
supplementary material; journal versio
Neutrino-Nucleus Reactions and Muon Capture in 12C
The neutrino-nucleus cross section and the muon capture rate are discussed
within a simple formalism which facilitates the nuclear structure calculations.
The corresponding formulae only depend on four types of nuclear matrix
elements, which are currently used in the nuclear beta decay. We have also
considered the non-locality effects arising from the velocity-dependent terms
in the hadronic current. We show that for both observables in 12C the higher
order relativistic corrections are of the order of ~5 only, and therefore do
not play a significant role. As nuclear model framework we use the projected
QRPA (PQRPA) and show that the number projection plays a crucial role in
removing the degeneracy between the proton-neutron two quasiparticle states at
the level of the mean field. Comparison is done with both the experimental data
and the previous shell model calculations. Possible consequences of the present
study on the determination of the neutrino oscillation
probability are briefly addressed.Comment: 29 pages, 6 figures, Revtex4. Several changes were made to the
previous manuscript, the results and final conclusions remain unalterable. It
has been accepted for publication as a Regular Article in Physical Review
Detection of gravitational waves from the QCD phase transition with pulsar timing arrays
If the cosmological QCD phase transition is strongly first order and lasts
sufficiently long, it generates a background of gravitational waves which may
be detected via pulsar timing experiments. We estimate the amplitude and the
spectral shape of such a background and we discuss its detectability prospects.Comment: 7 pages, 5 figs. Version accepted by PR
Bracelets of Pride and Guilt? An Experimental Test of Self-Signaling in Charitable Giving
Self-signaling theory argues that individuals partly behave prosocially to create or uphold a favorable self-image. To study self-signaling theory, we investigate whether increasing self-image concerns affects charitable giving. In our experiment subjects divide 20 euros between themselves and a charity. Some randomly determined participants are induced to wear a bracelet for the two weeks following their donation decision. This bracelet serves as a private reminder of the experiment, thus making the donation more important for future self-image. If self-signaling plays a role, participants having to wear the bracelet should donate more. We do not find that wearing a bracelet has any effect on donation behavior. This holds although subjects having to wear the bracelet report that at the moment of making the donation, they expect to more often remember the experiment in the following two weeks
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