5,680 research outputs found
More than Human Sacrifice: Teaching about the Aztecs in the New Latino South
This essay details an extended lesson I created to teach about Aztec/Mexica resistance to Spanish conquest in a sixth grade classroom within the context of the New Latino South. Rather than concentrate on the familiar tropes of human sacrifice and European exploration, I centered Aztec/Mexica philosophy, arts, and resistance in order to disrupt majoritarian narratives reified in Social Studies courses. Decentering and complicating the dominant narrative about Aztec/Mexica culture is one way educators can challenge dominant, and negative, discourse about burgeoning Latinx communities. I argue that in order for schools to help remedy deficit perspectives of Latinx people, especially in newer receiver contexts like the South(east), educators must be willing to find ways to explicitly teach against such narratives
Sensitivity of Neutrino Mass Experiments to the Cosmic Neutrino Background
The KATRIN neutrino experiment is a next-generation tritium beta decay
experiment aimed at measuring the mass of the electron neutrino to better than
200 meV at 90% C.L. Due to its intense tritium source, KATRIN can also serve as
a possible target for the process of neutrino capture, {\nu}e +3H \to 3He+ +
e-. The latter process, possessing no energy threshold, is sensitive to the
Cosmic Neutrino Background (C{\nu}B). In this paper, we explore the potential
sensitivity of the KATRIN experiment to the relic neutrino density. The KATRIN
experiment is sensitive to a C{\nu}B over-density ratio of 2.0x 10^9 over
standard concordance model predictions (at 90% C.L.), addressing the validity
of certain speculative cosmological models
Relativistic Cyclotron Radiation Detection of Tritium Decay Electrons as a New Technique for Measuring the Neutrino Mass
The shape of the beta decay energy distribution is sensitive to the mass of
the electron neutrino. Attempts to measure the endpoint shape of tritium decay
have so far seen no distortion from the zero-mass form, thus placing an upper
limit of m_nu_beta < 2.3 eV. Here we show that a new type of electron energy
spectroscopy could improve future measurements of this spectrum and therefore
of the neutrino mass. We propose to detect the coherent cyclotron radiation
emitted by an energetic electron in a magnetic field. For mildly relativistic
electrons, like those in tritium decay, the relativistic shift of the cyclotron
frequency allows us to extract the electron energy from the emitted radiation.
We present calculations for the energy resolution, noise limits, high-rate
measurement capability, and systematic errors expected in such an experiment.Comment: 4 pages, 2 figure
Sampling Theorem and Discrete Fourier Transform on the Hyperboloid
Using Coherent-State (CS) techniques, we prove a sampling theorem for
holomorphic functions on the hyperboloid (or its stereographic projection onto
the open unit disk ), seen as a homogeneous space of the
pseudo-unitary group SU(1,1). We provide a reconstruction formula for
bandlimited functions, through a sinc-type kernel, and a discrete Fourier
transform from samples properly chosen. We also study the case of
undersampling of band-unlimited functions and the conditions under which a
partial reconstruction from samples is still possible and the accuracy of
the approximation, which tends to be exact in the limit .Comment: 22 pages, 2 figures. Final version published in J. Fourier Anal. App
Kondo Resonance Decoherence by an External Potential
The Kondo problem, for a quantum dot (QD), subjected to an external bias, is
analyzed in the limit of infinite Coulomb repulsion by using a consistent
equations of motion method based on a slave-boson Hamiltonian. Utilizing a
strict perturbative solution in the leads-dot coupling, T, to T^4 and T^6
orders, we calculate the QD spectral density and conductance, as well as the
decoherent rate that drive the systemm from the strong to the weak coupling
regime. Our results indicate thet the weak coupling regime is reached for
voltages larger than a few units of the Kondo temperature.Comment: 5 figure
Diffuse interstellar bands {\lambda}5780 and {\lambda}5797 in the Antennae Galaxy as seen by MUSE
ABRIDGED: Diffuse interstellar bands (DIBs) are faint spectral absorption
features of unknown origin. Research on DIBs beyond the Local Group (LG) will
surely blossom in the era of the ELTs. A possibility that needs to be explored
is the use of integral field spectrographs. We do so by using MUSE data for the
Antennae Galaxy, the closest major galaxy merger. High S-to-N spectra were
created by co-adding the signal of many spatial elements. The emission of the
underlying stellar population was modeled using STARLIGHT. To our knowledge, we
have derived the first maps for the DIBs at l5780 and l5797 in galaxies outside
the LG. The l5780 DIB was detected in an area of ~0.6 arcmin2, corresponding to
a linear scale of ~25 kpc2. This region was sampled using >200 independent
lines of sight. The DIB l5797 was detected in >100 independent lines of sight.
Both DIBs are associated with a region with high emission in the HI 21 cm line,
implying a connection between atomic gas and DIBs, as the correlations for the
Milky Way also suggest. Conversely, there is mild spatial association between
the two DIBs and the molecular gas, in agreement with results for our Galaxy
that indicate a lack of correlation between DIBs and molecular gas. The overall
structure for the DIB strength distribution and extinction are comparable.
Within the system, the l5780 DIB clearly correlates with the extinction. Both
DIBs follow the relationship between equivalent width and reddening when data
for several galaxies are considered. Unidentified Infrared emission Bands
(UIBs, likely caused by PAHs) and the l5780 and l5797 DIBs show similar but not
identical spatial distributions. We attribute the differences to extinction
effects without necessarily implying a radically different nature of the
respective carriers. The results illustrate the enormous potential of integral
field spectrographs for extragalactic DIB research.Comment: 12 pages, 13 figures, accepted by Astronomy & Astrophysics; version
corrected by English edito
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