The Infrared Diameter -- Velocity Dispersion Relation for Elliptical Galaxies

Using single channel infrared photometry from the literature, a provisional K-band diameter--velocity dispersion relation for elliptical galaxies in the Coma and Virgo clusters is derived. The Coma cluster relation has \~1.5 times lower scatter at K than in B or V. Excluding 4 outliers, the RMS scatter at K for 24 galaxies in Coma is only 4.8% in distance, close to the limit implied by the observational errors. Distance estimates based on the IR \Dsig relation will be more accurate than those derived from optical data. The improvement in the infrared is attributed to a decrease in sensitivity to stellar population parameters (age, metallicity, and slope of the IMF) as well as lower internal extinction from dust compared to the optical. That the \Dsig relation has a larger scatter in the optical indicates that there are detectable, but small, stellar population or dust content differences among the Coma ellipticals. Since the \Dsig relations are based on the fundamental plane, this result promises that the fundamental plane is thinner in the infrared than it is in the optical. Infrared photometric data available for Virgo are limited to just 13 objects; the spread in distance due to the depth of the cluster precludes any significant improvement over B and V. A relative Coma-Virgo distance of 5.56 is derived from the K band data, in agreement with estimates in other colors and using other techniques, indicating that there is no significant age difference between Virgo and Coma ellipticals.Comment: 10 pages, 3 Postscript figures, uuencoded and Z-compressed with csh script uufiles; to appear in the September Astronomical Journa

Free Will Skepticism and the Question of Creativity: Creativity, Desert, and Self-Creation

Free will skepticism maintains that what we do, and the way we are, is ultimately the result of factors beyond our control and because of this we are never morally responsible for our actions in the basic desert sense—the sense that would make us truly deserving of praise and blame. In recent years, a number of contemporary philosophers have advanced and defended versions of free will skepticism, including Derk Pereboom (2001, 2014), Galen Strawson (2010), Neil Levy (2011), Bruce Waller (2011, 2015), and myself (Caruso 2012, 2013, forthcoming). Critics, however, often complain that adopting such views would have dire consequences for ourselves, society, morality, meaning, and the law. They fear, for instance, that relinquishing belief in free will and basic desert moral responsibility would leave us unable to adequately deal with criminal behavior, increase anti-social conduct, and undermine meaning in life. In response, free will skeptics argue that life without free will and basic desert moral responsibility would not be as destructive as many people believe (see, e.g., Pereboom 2001, 2014; Waller 2011, 2015; Caruso 2016, forthcoming). According to optimistic skeptics, prospects of finding meaning in life or of sustaining good interpersonal relationships, for instance, would not be threatened. And although retributivism and severe punishment, such as the death penalty, would be ruled out, incapacitation and rehabilitation programs would still be justified (see Pereboom 2001, 2013, 2014; Levy 2012; Caruso 2016; Pereboom and Caruso, forthcoming). In this paper, I attempt to extend this general optimism about the practical implications of free will skepticism to the question of creativity. In Section I, I spell out the question of creativity and explain why it’s relevant to the problem of free will. In Section II, I identify three different conceptions of creativity and explain the practical concerns critics have with free will skepticism. In Section III, I distinguish between three different conceptions of moral responsibility and argue that at least two of them are consistent with free will skepticism. I further contend that forward-looking accounts of moral responsibility, which are perfectly consistent with free will skepticism, can justify calling agents to account for immoral behavior as well as providing encouragement for creative activities since these are important for moral and creative formation and development. I conclude in Section IV by arguing that relinquishing belief in free will and basic desert would not mean the death of creativity or our sense of achievement since important and realistic conceptions of both remain in place

Stably Extending Two-Dimensional Bipedal Walking to Three Dimensions

In this paper we develop a feedback control law that results in stable walking gaits on flat ground for a three-dimensional bipedal robotic walker given stable walking gaits for a two-dimensional bipedal robotic walker. This is achieved by combining disparate techniques that have been employed in the bipedal robotic community: controlled symmetries, geometric reduction and hybrid zero dynamics. Controlled symmetries are utilized to obtain stable walking gaits for a two-dimensional bipedal robot walking on flat ground. These are related to walking gaits for a three-dimensional (hipless) bipedal robot through the use of geometric reduction. Finally, these walking gaits in three dimensions are made stable through the use of hybrid zero dynamics

A geometric approach to three-dimensional hipped bipedal robotic walking

This paper presents a control law that results in stable walking for a three-dimensional bipedal robot with a hip. To obtain this control law, we utilize techniques from geometric reduction, and specifically a variant of Routhian reduction termed functional Routhian reduction, to effectively decouple the dynamics of the three-dimensional biped into its sagittal and lateral components. Motivated by the decoupling afforded by functional Routhian reduction, the control law we present is obtained by combining three separate control laws: the first shapes the potential energy of the sagittal dynamics of the biped to obtain stable walking gaits when it is constrained to the sagittal plane, the second shapes the total energy of the walker so that functional Routhian reduction can be applied to decoupling the dynamics of the walker for certain initial conditions, and the third utilizes an output zeroing controller to stabilize to the surface defining these initial conditions. We numerically verify that this method results in stable walking, and we discuss certain attributes of this walking gait

On the Optimization of Mixture Resolving Signal Processing Structures

Mixture resolving signal processing optimization with optimum linear detection operators and mixture resolving estimator

Free Will: Real or Illusion - A Debate

Debate on free will with Christian List, Gregg Caruso, and Cory Clark. The exchange is focused on Christian List's book Why Free Will Is Real