15,979 research outputs found
Noticing for Equity to Sustain Multilingual Literacies
This department explores how teachers can sustain students’ multilingual literacies and reimagine literacy learning across multiple contexts in conversation with researchers, practitioners, and communities
Cyclic brightening in the short-period WZ Sge-type cataclysmic variable SDSS J080434.20+510349.2
We have observed a new cataclysmic variable (CV) SDSS J080434.20+510349.2 and
study the origin of a long-term variability found in its light curve.
Multi-longitude time-resolved photometric observations were carried out to
analyze the uncommon behavior also found recently in two newly discovered CVs.
This study of SDSS J080434.20+510349.2 mainly concerns the understanding of the
nature of the observed double-humped light curve and its relation to a cyclic
brightening occurring during quiescence. The observations were obtained early
in 2007, when the object was at about V~17.1, 0.4 mag brighter than the
pre-outburst magnitude. The light curve shows a sinusoidal variability with an
amplitude of about 0.07 mag and a periodicity of 42.48 min, which is half of
the orbital period of the system. In addition, we have observed two
"mini-outbursts" of the system up to 0.6 mag, with a duration of about 4 days
each. The "mini-outburst" had a symmetric profile and repeated in about 32
days. Subsequent monitoring of the system shows a cyclical behaviour of such
"mini-outbursts" with a similar recurrence period. The origin of the
double-humped light curve and the periodic brightening is discussed in the
light of the evolutionary state of SDSS J080434.20+510349.2.Comment: 7 pages, 6 figures, Accepted by A&A, typos added, figure correcte
Trophic effects of sponge feeding within Lake Baikal\u27s littoral zone .2. Sponge abundance, diet, feeding efficiency, and carbon flux
Endemic freshwater demosponges in the littoral zone of Lake Baikal, Russia, dominate the benthic biomass, covering 44% of the benthos. We measured in situ sponge abundance and,orating and calculated sponge-mediated Fluxes of picoplankton (plankton \u3c2 mu m) for two common species, Baikalospongia intermedia and Baikalospongia bacillifera. By means of dual-beam how cytometry, we found retention efficiencies ranging from 58 to 99% for four types of picoplankton: heterotrophic bacteria, Synechococcus-type cyanobacteria, autotrophic picoplankton with one chloroplast, and autotrophic picoplankton with two chloroplasts. By using a general model for organism-mediated fluxes, we conservatively estimate that through active suspension feeding, sponges are a sink for 1.97 g C d(-1) m(-1), mostly from procaryotic cell types. Furthermore, grazing by these extensive sponge communities can create a layer of picoplankton-depleted water overlying the benthic community in this unique lake
Search for the electric dipole moment of the electron with thorium monoxide
The electric dipole moment of the electron (eEDM) is a signature of
CP-violating physics beyond the Standard Model. We describe an ongoing
experiment to measure or set improved limits to the eEDM, using a cold beam of
thorium monoxide (ThO) molecules. The metastable state in ThO
has important advantages for such an experiment. We argue that the statistical
uncertainty of an eEDM measurement could be improved by as much as 3 orders of
magnitude compared to the current experimental limit, in a first-generation
apparatus using a cold ThO beam. We describe our measurements of the state
lifetime and the production of ThO molecules in a beam, which provide crucial
data for the eEDM sensitivity estimate. ThO also has ideal properties for the
rejection of a number of known systematic errors; these properties and their
implications are described.Comment: v2: Equation (11) correcte
Human Time-Frequency Acuity Beats the Fourier Uncertainty Principle
The time-frequency uncertainty principle states that the product of the
temporal and frequency extents of a signal cannot be smaller than .
We study human ability to simultaneously judge the frequency and the timing of
a sound. Our subjects often exceeded the uncertainty limit, sometimes by more
than tenfold, mostly through remarkable timing acuity. Our results establish a
lower bound for the nonlinearity and complexity of the algorithms employed by
our brains in parsing transient sounds, rule out simple "linear filter" models
of early auditory processing, and highlight timing acuity as a central feature
in auditory object processing.Comment: 4 pages, 2 figures; Accepted at PR
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