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When users control the algorithms: Values expressed in practices on the twitter platform
Recent interest in ethical AI has brought a slew of values, including fairness, into conversations about technology design. Research in the area of algorithmic fairness tends to be rooted in questions of distribution that can be subject to precise formalism and technical implementation. We seek to expand this conversation to include the experiences of people subject to algorithmic classification and decision-making. By examining tweets about the “Twitter algorithm” we consider the wide range of concerns and desires Twitter users express. We find a concern with fairness (narrowly construed) is present, particularly in the ways users complain that the platform enacts a political bias against conservatives. However, we find another important category of concern, evident in attempts to exert control over the algorithm. Twitter users who seek control do so for a variety of reasons, many well justified. We argue for the need for better and clearer definitions of what constitutes legitimate and illegitimate control over algorithmic processes and to consider support for users who wish to enact their own collective choices
A VLBI polarization study of SiO masers towards VY CMa
Maser emission from the SiO molecule has been widely observed in the
near-circumstellar envelopes of late-type, evolved stars. VLBI images can
resolve individual SiO maser spots, providing information about the kinematics
and magnetic field in the extended atmospheres of these stars. This poster
presents full polarization images of several SiO maser lines towards the
supergiant star VY CMa. VY CMa is a particularly strong SiO maser source and
allows observations of a wide range of maser transitions. We discuss
implications of these observations for VY CMa morphology, polarization, and
pumping models.Comment: 3 pages, 1 figure: based on a poster paper at IAU Symposium 242:
Astrophysical masers and their environments, held at Alice Springs
(Australia), from March 12-16, 200
Issues Relevant to C-H Activation at Platinum(II): Comparative Studies between Cationic, Zwitterionic, and Neutral Platinum(II) Compounds in Benzene Solution
Cationic late metal systems are being highly scrutinized due to
their propensity to mediate so-called electrophilic C-H
activation reactions. This contribution compares the reactivity
of highly reactive cationic platinum(II) systems with
structurally related but neutral species. Our experimental
design exploits isostructural neutral and cationic complexes
supported by bis(phosphine) ligands amenable to mechanistic
examination in benzene solution. The data presented herein
collectively suggests that neutral platinum complexes can be
equally if not more reactive towards benzene than their
cationic counter-parts. Moreover, a number of unexpected
mechanistic distinctions between the two systems arise that
help to explain their respective reactivity
The angular power spectrum of radio emission at 2.3 GHz
We have analysed the Rhodes/HartRAO survey at 2326 MHz and derived the global
angular power spectrum of Galactic continuum emission. In order to measure the
angular power spectrum of the diffuse component, point sources were removed
from the map by median filtering. A least-square fit to the angular power
spectrum of the entire survey with a power law spectrum C_l proportional to
l^{-alpha}, gives alpha = 2.43 +/- 0.01 for l = 2-100. The angular power
spectrum of radio emission appears to steepen at high Galactic latitudes and
for observed regions with |b| > 20 deg, the fitted spectral index is alpha =
2.92 +/- 0.07. We have extrapolated this result to 30 GHz (the lowest frequency
channel of Planck) and estimate that no significant contribution to the sky
temperature fluctuation is likely to come from synchrotron at degree-angular
scalesComment: 10 pages, 10 figures, accepted for publication by Astronomy &
Astrophysic
Cavity state preparation using adiabatic transfer
We show how to prepare a variety of cavity field states for multiple
cavities. The state preparation technique used is related to the method of
stimulated adiabatic Raman passage or STIRAP. The cavity modes are coupled by
atoms, making it possible to transfer an arbitrary cavity field state from one
cavity to another, and also to prepare non-trivial cavity field states. In
particular, we show how to prepare entangled states of two or more cavities,
such as an EPR state and a W state, as well as various entangled superpositions
of coherent states in different cavities, including Schrodinger cat states. The
theoretical considerations are supported by numerical simulations.Comment: 11 pages, 9 figures. Accepted in Phys. Rev.
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