120 research outputs found
Single Transferable Vote with Borda Elimination: A New Vote Counting System
Dummett (1997) notes particular difficulties with single transferable vote (STV) and proposes an alternative vote counting system called âQuota/Borda systemâ (QBS) to remedy specific difficulties. I propose an alternative system, structurally related to QBS, which accomplishes similar solutions but has some significant differences. This alternative system is identical to STV in all aspects except one. It eliminates candidates in reverse order of their Borda scores rather than by their current ranking of first-place votes. I designate this system STV with Borda elimination (STV-B). STV-B and QBS share general features. They retain proportional representation from STV. However, they differ from STV is two critical manners. First, both permit some influence on candidate selection to occur between voting blocks. Second, they are much more stable than STV when subjected to small changes in voter preferences. Outcomes from STV-B differ from QBS outcomes in two ways. Under STV-B, a minority that shares some preferences may elect a candidate even if the minority is not a solid coalition, as is required for minorities under QBS. Further, QBS always selects Borda winners, either for a minority or overall. STV-B may reject a Borda winner through emphasis on each voterâs most preferred candidates.
Insecure Participation: Experiments In A One Day Introduction To Economics
Classroom experiments and exercises served as a one-day introduction to economics for students who felt insecure about taking first year business classes. The first experiment addresses demand in isolation while the second addresses supply. Supply, demand and equilibrium are integrated in a pit market in which all students have equal expected profits. A monopoly pricing exercise addresses market failure. Exercises use many incremental questions to reveal principles of microeconomics. Evaluations show that at the end of the program, students were familiar with economic results and concepts, and were more comfortable with taking economics.
Standard Voting Power Indices Work: An Experimental Investigation of Pure Voting Power
We evaluate the accuracy of power indices by experimentally measuring the political power embodied in blocks of votes per se. The experiment incorporates several subjects interacting in online chat rooms under supervision. Chat rooms and processes for selecting subjects reduce or eliminate extraneous political forces leaving logrolling as the primary political force. Results show that two standard power indices reflect voting power while other power indices and proportionality do not.Voting, Power Index, P Power, Shapley-Shubik, Banzhaf, Johnston, Burgin, Experiment.
Focused Power: Experimental Manifestation of the Shapley-Shubik Power Index
Experiments evaluate the fit of the Shapley-Shubik Power Index to a controlled human environment. Subjects with differing votes divide a fixed purse by majority rule in online chat rooms under supervision. Earnings serve as a measure of power. Chat rooms and processes for selecting subjects reduce or eliminate extraneous political forces, leaving logrolling as the primary political force. Initial proposals by subjects for division of the purse allow measurement of effects from focal points and transaction costs. Net results closely fit the Shapley-Shubik Power Index.Voting, Power Index, Focal Point, Shapley-Shubik, Experiment
Insecure Participation: Experiments in a One-Day Introduction to Economics, with Revised Experiments and Exercises
Classroom experiments and exercises served as a one-day introduction to economics for students who felt insecure about taking first year business classes. The first experiment addresses demand in isolation, while the second addresses supply. A third integrates supply, demand and equilibrium in a pit market with all students having equal expected profits. A monopoly pricing exercise addresses market failure. Exercises use many incremental questions to reveal principles of microeconomics. Evaluations show that at the end of the program, students were familiar with economic results and concepts, and were more comfortable with taking economics.classroom experiments, exercises, principles, bond, auction, pit market
Star formation, starbursts and quenching across the Coma supercluster
We analyse Spitzer MIPS 24micron observations, and SDSS (DR7) optical
broadband photometry and spectra, to investigate the star formation (SF)
properties of galaxies residing in the Coma supercluster region. We find that
SF in dwarf galaxies is quenched only in the high density environment at the
centre of clusters and groups, but passively-evolving massive galaxies are
found in all environments, indicating that massive galaxies can become passive
via internal processes. We find AGN activity is suppressed in the cluster
cores. We present evidence for a strong dependence of the mechanism(s)
responsible for quenching SF in dwarf galaxies on the cluster potential. We
find a significant increase in the mean EW of Halpha among star-forming dwarf
galaxies in the infall regions of the Coma cluster and the core of Abell 1367
with respect to the overall supercluster population, indicative of the
infalling dwarf galaxies undergoing a starburst phase. We identify these
starburst galaxies as the precursors of the post-starburst k+A galaxies. We
find that 11.4% of all dwarf (z mag > 15) galaxies in the Coma cluster and 4.8%
in the Abell 1367 have k+A like spectra, while this fraction is just 2.1% when
averaged over the entire supercluster region. We show that in the centre of the
Coma cluster, the (24-z) colour of galaxies is correlated with their optical
(g-r) colour and Halpha emission. By analysing the projected phase space
distribution of galaxies detected at 24micron in Coma, we find that the
(optically) red 24 micron detected galaxies follow the general distribution of
`all' the spectroscopic members, but their (optically) blue counterparts show
interesting features, indicative of recent infall.Comment: 17 pages, 14 figures, accepted for publicaton in MNRA
The WiggleZ Dark Energy Survey: the transition to large-scale cosmic homogeneity
We have made the largest-volume measurement to date of the transition to
large-scale homogeneity in the distribution of galaxies. We use the WiggleZ
survey, a spectroscopic survey of over 200,000 blue galaxies in a cosmic volume
of ~1 (Gpc/h)^3. A new method of defining the 'homogeneity scale' is presented,
which is more robust than methods previously used in the literature, and which
can be easily compared between different surveys. Due to the large cosmic depth
of WiggleZ (up to z=1) we are able to make the first measurement of the
transition to homogeneity over a range of cosmic epochs. The mean number of
galaxies N(<r) in spheres of comoving radius r is proportional to r^3 within
1%, or equivalently the fractal dimension of the sample is within 1% of D_2=3,
at radii larger than 71 \pm 8 Mpc/h at z~0.2, 70 \pm 5 Mpc/h at z~0.4, 81 \pm 5
Mpc/h at z~0.6, and 75 \pm 4 Mpc/h at z~0.8. We demonstrate the robustness of
our results against selection function effects, using a LCDM N-body simulation
and a suite of inhomogeneous fractal distributions. The results are in
excellent agreement with both the LCDM N-body simulation and an analytical LCDM
prediction. We can exclude a fractal distribution with fractal dimension below
D_2=2.97 on scales from ~80 Mpc/h up to the largest scales probed by our
measurement, ~300 Mpc/h, at 99.99% confidence.Comment: 21 pages, 16 figures, accepted for publication in MNRA
Energy Saving on Campus: A comparison of students' attitudes and reported behaviours in the UK and Portugal
Energy saving on campus is an increasingly important part of universitiesâ responses to climate change, but can only be fully realised through a partnership between institutions and students. This study explores similarities and differences between studentsâ energy-related attitudes and reported behaviours, as well as their perceptions of their institutionâs energy saving efforts using data from two universities in the United Kingdom (UK) and one in Portugal. The results indicate that there are differences between the studentsâ responses at the selected universities which appear to reflect the national context and diverse institutional priorities. Key differences include the variation between studentsâ perceptions of individual agency and their universityâs environmental practices (stronger in the UK) and studentsâ sense of collective agency and trust in the government and business (stronger in Portugal). The study is the first to attempt a comparison between students from institutions in different countries in relation to energy saving. It provides a foundation to extend the comparison to other institutions and other countries, and to expand the research to encompass actual energy use, in relation to perceived energy use
The Oxford-Dartmouth Thirty Degree Survey I: Observations and Calibration of a Wide-Field Multi-Band Survey
The Oxford Dartmouth Thirty Degree Survey (ODTS) is a deep, wide, multi-band
imaging survey designed to cover a total of 30 square degrees in BVRi'Z, with a
subset of U and K band data, in four separate fields of 5-10 deg^2 centred at
00:18:24 +34:52, 09:09:45 +40:50, 13:40:00 +02:30 and 16:39:30 +45:24.
Observations have been made using the Wide Field Camera on the 2.5-m Isaac
Newton Telescope in La Palma to average limiting depths (5 sigma Vega, aperture
magnitudes) of U=24.8, B=25.6, V=25.0, R=24.6, and i'=23.5, with observations
taken in ideal conditions reaching the target depths of U=25.3, B=26.2, V=25.7,
R=25.4, and i'=24.6. The INT Z band data was found to be severely effected by
fringing and, consequently, is now being obtained at the MDM observatory in
Arizona. A complementary K-band survey has also been carried out at MDM,
reaching an average depth of K_{5\sigma}~18.5. At present, approximately 23
deg^2 of the ODTS have been observed, with 3.5 deg^2 of the K band survey
completed. This paper details the survey goals, field selection, observation
strategy and data reduction procedure, focusing on the photometric calibration
and catalogue construction. Preliminary photometric redshifts have been
obtained for a subsample of the objects with R <= 23. These results are
presented alongside a brief description of the photometric redshift
determination technique used. The median redshift of the survey is estimated to
be z~0.7 from a combination of the ODTS photometric redshifts and comparison
with the redshift distributions of other surveys. Finally, galaxy number counts
for the ODTS are presented which are found to be in excellent agreement with
previous studies.Comment: 18 pages, 21 figures, Accepted for publication in MNRA
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