Stellar Masses of High-Redshift Galaxies

We present constraints on the stellar-mass distribution of distant galaxies. These stellar-mass estimates derive from fitting population-synthesis models to the galaxies' observed multi-band spectrophotometry. We discuss the complex uncertainties (both statistical and systematic) that are inherent to this method, and offer future prospects to improve the constraints. Typical uncertainties for galaxies at z ~ 2.5 are ~ 0.3 dex (statistical), and factors of ~ 3 (systematic). By applying this method to a catalog of NICMOS-selected galaxies in the Hubble Deep Field North, we generally find a lack of high-redshift galaxies (z > 2) with masses comparable to those of present-day ``L*'' galaxies. At z < 1.8, galaxies with L*-sized masses do emerge, but with a number density below that at the present epoch. Thus, it seems massive, present-day galaxies were not fully assembled by z ~ 2.5, and that further star formation and/or merging are required to assemble them from these high-redshift progenitors. Future progress on this subject will greatly benefit from upcoming surveys such as those planned with HST/ACS and SIRTF.Comment: 7 pages, 5 figures. To appear in The Mass of Galaxies at Low and High Redshift, eds. R. Bender & A. Renzini (ESO Astrophysics Symposia, Springer-Verlag), Venice, 24-26 Oct 200

“I’m Here to Do Business. I’m Not Here to Play Games.” Work, Consumption, and Masculinity in \u3ci\u3eStorage Wars\u3c/i\u3e

This essay examines the first season of Storage Wars and suggests the program helps mediate the putative crisis in American masculinity by suggesting that traditional male skills are still essential where knowledge supplants manual labor. We read representations of “men at work” in traditionally “feminine” consumer markets, as a form of masculine recuperation situated within the culture of White male injury. Specifically, Storage Wars appropriates omnivorous consumption, thrift, and collaboration to fit within the masculine repertoire of self-reliance, individualism, and competition. Thus, the program adapts hegemonic masculinity by showcasing male auction bidders adeptly performing feminine consumer practices. Whether the feminine is assimilated into the male body or represented as its Other, we contend that the expressions of masculinity in Storage Wars render women obsolete and subjugated in the marketplaces of the 21st-century economy and contribute to the mediation of the contemporary crisis in masculinity

Lyman Break Galaxies in the NGST Era

With SIRTF and NGST in the offing, it is interesting to examine what the stellar populations of z~3 galaxies models imply for the existence and nature of Lyman-break galaxies at higher redshift. To this end, we ``turn back the clock'' on the stellar population models that have been fit to optical and infrared data of Lyman-break galaxies at z~3. The generally young ages (typically 10^8 +- 0.5 yr) of these galaxies imply that their stars were not present much beyond z=4. For smooth star-formation histories SFR(t) and Salpeter IMFs, the ionizing radiation from early star-formation in these galaxies would be insufficient to reionize the intergalactic medium at z~6, and the luminosity density at z~4 would be significantly lower than observed. We examine possible ways to increase the global star-formation rate at higher redshift without violating the stellar-population constraints at z~3.Comment: To appear in "The Mass of Galaxies at Low and High Redshift", ed. R. Bender and A. Renzini, ESO Astrophysics Symposia, Springer-Verlag 7 Pages, 2 figure

Zeptonewton force sensing with nanospheres in an optical lattice

Optically trapped nanospheres in high-vaccum experience little friction and hence are promising for ultra-sensitive force detection. Here we demonstrate measurement times exceeding $10^5$ seconds and zeptonewton force sensitivity with laser-cooled silica nanospheres trapped in an optical lattice. The sensitivity achieved exceeds that of conventional room-temperature solid-state force sensors, and enables a variety of applications including electric field sensing, inertial sensing, and gravimetry. The optical potential allows the particle to be confined in a number of possible trapping sites, with precise localization at the anti-nodes of the optical standing wave. By studying the motion of a particle which has been moved to an adjacent trapping site, the known spacing of the lattice anti-nodes can be used to calibrate the displacement spectrum of the particle. Finally, we study the dependence of the trap stability and lifetime on the laser intensity and gas pressure, and examine the heating rate of the particle in high vacuum in the absence of optical feedback cooling.Comment: 5 pages, 4 figures, minor changes, typos corrected, references adde

Remedies for Robots

What happens when artificially intelligent robots misbehave? The question is not just hypothetical. As robotics and artificial intelligence systems increasingly integrate into our society, they will do bad things. We seek to explore what remedies the law can and should provide once a robot has caused harm. Remedies are sometimes designed to make plaintiffs whole by restoring them to the condition they would have been in “but for” the wrong. But they can also contain elements of moral judgment, punishment, and deterrence. In other instances, the law may order defendants to do (or stop doing) something unlawful or harmful. Each of these goals of remedies law, however, runs into difficulties when the bad actor in question is neither a person nor a corporation but a robot. We might order a robot—or, more realistically, the designer or owner of the robot—to pay for the damages it causes. But it turns out to be much harder for a judge to “order” a robot, rather than a human, to engage in or refrain from certain conduct. Robots can’t directly obey court orders not written in computer code. And bridging the translation gap between natural language and code is often harder than we might expect. This is particularly true of modern artificial intelligence techniques that empower machines to learn and modify their decision-making over time. If we don’t know how the robot “thinks,” we won’t know how to tell it to behave in a way likely to cause it to do what we actually want it to do. Moreover, if the ultimate goal of a legal remedy is to encourage good behavior or discourage bad behavior, punishing owners or designers for the behavior of their robots may not always make sense—if only for the simple reason that their owners didn’t act wrongfully in any meaningful way. The same problem affects injunctive relief. Courts are used to ordering people and companies to do (or stop doing) certain things, with a penalty of contempt of court for noncompliance. But ordering a robot to abstain from certain behavior won’t be trivial in many cases. And ordering it to take affirmative acts may prove even more problematic. In this Article, we begin to think about how we might design a system of remedies for robots. Robots will require us to rethink many of our current doctrines. They also offer important insights into the law of remedies we already apply to people and corporations

You Might be a Robot

As robots and artificial intelligence (Al) increase their influence over society, policymakers are increasingly regulating them. But to regulate these technologies, we first need to know what they are. And here we come to a problem. No one has been able to offer a decent definition of robots arid AI-not even experts. What\u27s more, technological advances make it harder and harder each day to tell people from robots and robots from dumb machines. We have already seen disastrous legal definitions written with one target in mind inadvertently affecting others. In fact, if you are reading this you are (probably) not a robot, but certain laws might already treat you as one. Definitional challenges like these aren\u27t exclusive to robots and Al. But today, all signs indicate we are approaching an inflection point. Whether it is citywide bans of robot sex brothels or nationwide efforts to crack down on ticket scalping bots, we are witnessing an explosion of interest in regulating robots, human enhancement technologies, and all things in between. And that, in turn, means that typological quandaries once confined to philosophy seminars can no longer be dismissed as academic. Want, for example, to crack down on foreign influence campaigns by regulating social media bots? Be careful not to define bot too broadly (like the Calfornia legislature recently did), or the supercomputer nestled in your pocket might just make you one. Want, instead, to promote traffic safety by regulating drivers? Be careful not to presume that only humans can drive (as our Federal Motor Vehicle Safety Standards do), or you may soon exclude the best drivers on the road. In this Article, we suggest that the problem isn\u27t simply that we haven\u27t hit upon the right definition. Instead, there may not be a right definition for the multifaceted, rapidly evolving technologies we call robots or AI. As we will demonstrate, even the most thoughtful of definitions risk being overbroad, underinclusive, or simply irrelevant in short order. Rather than trying in vain to find the perfect definition, we instead argue that policymakers should do as the great computer scientist, Alan Turing, did when confronted with the challenge of defining robots: embrace their ineffable nature. We offer several strategies to do so. First, whenever possible, laws should regulate behavior, not things (or as we put it, regulate verbs, not nouns). Second, where we must distinguish robots from other entities, the law should apply what we call Turing\u27s Razor, identifying robots on a case-by-case basis. Third, we offer six functional criteria for making these types of I know it when I see it determinations and argue that courts are generally better positioned than legislators to apply such standards. Finally, we argue that if we must have definitions rather than apply standards, they should be as short-term and contingent as possible. That, in turn, suggests that regulators-not legislators-should play the defining role