2,282 research outputs found
Measuring the cosmological constant with redshift surveys
It has been proposed that the cosmological constant might be
measured from geometric effects on large-scale structure. A positive vacuum
density leads to correlation-function contours which are squashed in the radial
direction when calculated assuming a matter-dominated model. We show that this
effect will be somewhat harder to detect than previous calculations have
suggested: the squashing factor is likely to be , given realistic
constraints on the matter contribution to . Moreover, the geometrical
distortion risks being confused with the redshift-space distortions caused by
the peculiar velocities associated with the growth of galaxy clustering. These
depend on the density and bias parameters via the combination , and we show that the main practical effect of a geometrical
flattening factor is to simulate gravitational instability with . Nevertheless, with datasets of sufficient size it is
possible to distinguish the two effects; we discuss in detail how this should
be done. New-generation redshift surveys of galaxies and quasars are
potentially capable of detecting a non-zero vacuum density, if it exists at a
cosmologically interesting level.Comment: MNRAS in press. 12 pages LaTeX including Postscript figures. Uses
mn.sty and epsf.st
Coevolutionary Approaches to Generating Robust Build-Orders for Real-Time Strategy Games
We aim to find winning build-orders for Real-Time Strategy games. Real-Time Strategy games provide a variety of challenges, from short-term control to longer term planning. We focus on a longer-term planning problem; which units to build and in what order to produce the units so a player successfully defeats the opponent. Plans which address unit construction scheduling problems in Real-Time Strategy games are called build-orders. A robust build-order defeats many opponents, while a strong build-order defeats opponents quickly. However, no single build-order defeats all other build-orders, and build-orders that defeat many opponents may still lose against a specific opponent. Other researchers have only investigated generating build-orders that defeat a specific opponent, rather than finding robust, strong build-orders. Additionally, previous research has not applied coevolutionary algorithms towards generating build-orders. In contrast, our research has three main contributions towards finding robust, strong build-orders. First, we apply a coevolutionary algorithm towards finding robust build-orders. Compared to exhaustive search, a genetic algorithm finds the strongest build-orders while a coevolutionary algorithm finds more robust build-orders. Second, we show that case-injection enables coevolution to learn from specific opponents while maintaining robustness. Build-orders produced with coevolution and case-injection learn to defeat or play like the injected build-orders. Third, we show that coevolved build-orders benefit from a representation which includes branches and loops. Coevolution will utilize multiple branches and loops to create build-orders that are stronger than build-orders without loops and branches. We believe this work provides evidence that coevolutionary algorithms may be a viable approach to creating robust, strong build-orders for Real-Time Strategy games
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Number of Pages: 4Integrative BiologyGeological Science
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Number of Pages: 2Integrative BiologyGeological Science
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Number of Pages: 2Integrative BiologyGeological Science
βGovernment by a Few Conservative Menβ: An Examination of Louis Boudinβs Understanding of the Abuse of the Judicial Power and the Decline of Judicial Restraint by the Supreme Court
For the first 150 years of the existence of the judicial power, it was liberals who advocated for the limited role that the Supreme Court should play in Americaβs constitutional democracy. Since the 1960βs and the Civil Rights Movement, there has been an increase in liberal judicial activism. This thesis seeks to explore the progression of judicial restraint and activism over the history of the Supreme Court through the eyes of Louis Boudin, a constitutional expert writing in the 1930βs. Boudin, a radical liberal, asserts in Government By Judiciary that the judicial branch has been constantly expanding its own power far beyond the scope intended by the Framers of the Constitution as evidenced by ever-increasing activism. Boudin believes the Judiciary is threatening the very existence of the American constitutional democracy. This paper provides and in depth analysis of Boudinβs arguments and applies them to the modern judicial power through the Rehnquist Court
Variation in _PNPLA3_ is associated with outcomes in alcoholic liver disease
Two recent genome-wide association studies have described associations of SNP variants in _PNPLA3_ with nonalcoholic fatty liver and plasma liver enzyme levels in population based cohorts. We investigated the contributions of these variants to clinical outcomes in Mestizo subjects with a history of excessive alcohol consumption. We show that non-synonymous variant rs738409[G] (I148M) in _PNPLA3_ is strongly associated with alcoholic liver disease and progression to alcoholic cirrhosis (unadjusted OR = 2.25, P = 1.7x10^-10^; ancestry-adjusted OR = 1.79, P = 1.9x10^-5^)
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