2,732 research outputs found
In Search of a Fair Bet in the Lottery
Although state-operated lotto games have the worst average expected payoffs among common games of chance, because the jackpot can accumulate, the maximum expected payoff is potentially unlimited. It is possible, therefore, that lotto can exhibit a positive expected return. This paper examines 18,000 drawings in 34 American lotteries and finds approximately 1 percent of these drawings provided players with a fair bet. If it were possible for a bettor to purchase every possible combination, however, most lotteries commonly experience circumstances where such a purchase would provide a positive return with 11 percent of the drawings providing a fair bet to the player.
An analysis of the relationship of school entrance age to mental age and school achievement in grades I, III, V, and VIII
Thesis (Ed.M.)--Boston Universit
Protein folding rates correlate with heterogeneity of folding mechanism
By observing trends in the folding kinetics of experimental 2-state proteins
at their transition midpoints, and by observing trends in the barrier heights
of numerous simulations of coarse grained, C-alpha model, Go proteins, we show
that folding rates correlate with the degree of heterogeneity in the formation
of native contacts. Statistically significant correlations are observed between
folding rates and measures of heterogeneity inherent in the native topology, as
well as between rates and the variance in the distribution of either
experimentally measured or simulated phi-values.Comment: 11 pages, 3 figures, 1 tabl
Spectroscopy of High-Redshift Supernovae from the ESSENCE Project: The First Four Years
We present the results of spectroscopic observations from the ESSENCE
high-redshift supernova (SN) survey during its first four years of operation.
This sample includes spectra of all SNe Ia whose light curves were presented by
Miknaitis et al. (2007) and used in the cosmological analyses of Davis et al.
(2007) and Wood-Vasey et al. (2007). The sample represents 273 hours of
spectroscopic observations with 6.5 - 10-m-class telescopes of objects detected
and selected for spectroscopy by the ESSENCE team. We present 174 spectra of
156 objects. Combining this sample with that of Matheson et al. (2005), we have
a total sample of 329 spectra of 274 objects. From this, we are able to
spectroscopically classify 118 Type Ia SNe. As the survey has matured, the
efficiency of classifying SNe Ia has remained constant while we have observed
both higher-redshift SNe Ia and SNe Ia farther from maximum brightness.
Examining the subsample of SNe Ia with host-galaxy redshifts shows that
redshifts derived from only the SN Ia spectra are consistent with redshifts
found from host-galaxy spectra. Moreover, the phases derived from only the SN
Ia spectra are consistent with those derived from light-curve fits. By
comparing our spectra to local templates, we find that the rate of objects
similar to the overluminous SN 1991T and the underluminous SN 1991bg in our
sample are consistent with that of the local sample. We do note, however, that
we detect no object spectroscopically or photometrically similar to SN 1991bg.
Although systematic effects could reduce the high-redshift rate we expect based
on the low-redshift surveys, it is possible that SN 1991bg-like SNe Ia are less
prevalent at high redshift.Comment: 21 pages, 17 figures, accepted to A
Exploring the Structure of Distant Galaxies with Adaptive Optics on the Keck-II Telescope
We report on the first observation of cosmologically distant field galaxies
with an high order Adaptive Optics (AO) system on an 8-10 meter class
telescope. Two galaxies were observed at 1.6 microns at an angular resolution
as high as 50 milliarcsec using the AO system on the Keck-II telescope. Radial
profiles of both objects are consistent with those of local spiral galaxies and
are decomposed into a classic exponential disk and a central bulge. A
star-forming cluster or companion galaxy as well as a compact core are detected
in one of the galaxies at a redshift of 0.37+/-0.05. We discuss possible
explanations for the core including a small bulge, a nuclear starburst, or an
active nucleus. The same galaxy shows a peak disk surface brightness that is
brighter than local disks of comparable size. These observations demonstrate
the power of AO to reveal details of the morphology of distant faint galaxies
and to explore galaxy evolution.Comment: 5 pages, Latex, 3 figures. Accepted for publication in P.A.S.
Variability of Red Supergiants in M31 from the Palomar Transient Factory
Most massive stars end their lives as Red Supergiants (RSGs), a short-lived
evolution phase when they are known to pulsate with varying amplitudes. The RSG
period-luminosity (PL) relation has been measured in the Milky Way, the
Magellanic Clouds and M33 for about 120 stars in total. Using over 1500 epochs
of R-band monitoring from the Palomar Transient Factory (PTF) survey over a
five-year period, we study the variability of 255 spectroscopically cataloged
RSGs in M31. We find that all RGSs brighter than M_K~ -10 mag
(log(L/L_sun)>4.8) are variable at dm_R>0.05 mag. Our period analysis finds 63
with significant pulsation periods. Using the periods found and the known
values of M_K for these stars, we derive the RSG PL relation in M31 and show
that it is consistent with those derived earlier in other galaxies of different
metallicities. We also detect, for the first time, a sequence of likely
first-overtone pulsations. Comparison to stellar evolution models from MESA
confirms the first overtone hypothesis and indicates that the variable stars in
this sample have 12 M_sun<M<24 M_sun. As these RSGs are the immediate
progenitors to Type II-P core-collapse supernovae (SNe), we also explore the
implication of their variability in the initial-mass estimates for SN
progenitors based on archival images of the progenitors. We find that this
effect is small compared to the present measurement errors.Comment: 17 pages, 10 figure
Addressing health inequities for same sex attracted women in New South Wales, Australia, who use drugs
ACON’s Alcohol and Other Drugs Program provides a Needle Syringe Program, peerbased harm reduction programs, drug education targeted at members of the lesbian, gay, bisexual and transgender (LGBT) community, and counselling services. The Lesbian Health Project works with lesbians and other same-sex attracted (SSA) women to improve their health and wellbeing through health promotion, peer education and community development programs as well as providing capacity development for mainstream service providers. In Australia, LGBT people have considerably higher rates of drug use than the general population. While there is considerable funding support from Australian state and federal governments for education interventions that address gay men’s drug use, it has been more difficult to address the needs of lesbians and other SSA women. Efforts to address lesbian health needs are hampered by lack of research, poor understanding of the issues by potential funding bodies, and the lack of a single defining health issue (such as HIV among gay men) around which to focus advocacy efforts. Equally problematic is the absence of consideration given to lesbians and SSA women in any Australian national and state health policies. In response to the consistently low uptake of both harm reduction and treatment services by SSA women, ACON has successfully advocated with a major funder of our drug and alcohol work to re-allocate some existing funding to produce SSAwomen specific drug resources, in the interests of equity. This project (currently under development) seeks to engage with networks of SSA women who use drugs and who do not normally access ACON’s drugs and alcohol services, to produce resources that ‘speak to’ their issue
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