Barbarism inc

The trajectory of the global capitalist economy at the beginning of the twenty first century is on a collision course with nature. Some of us used to joke that if corporations could bottle and sell the air that we breathe they would do it. Well, now nobody is laughing. The summit of these eight richest countries in the world - Britain, Canada, France, Germany, Italy, Japan, Russia and the United States - will meet in July 2005 in Scotland. The G8 have consistently imposed a neo-liberal economic model that benefits the rich and powerful at the expense of the most destitute people in the world. This type of economics is characterized by privatization, deregulation and trade liberalization

Naming the problem

Everyone, even the most die-hard defender of the established order recognizes that we face serious social and environmental problems. The news media regularly circulate the latest figures on the latest social problems. The country with the worst pollution, highest infant mortality, lowest life expectancy, epidemic rates of drug abuse, poverty, anti-social behaviour. But the mainstream media, popular debate and elite discussion treat these - at best- as a procession of seemingly unrelated and inexplicable facts and events. At worst the tendency is to suggest that whatever the problem - racism, obesity, unemployment, famine, war - that the people affected are in some way culpable. If in doubt, blame the victim. Either way, the context necessary to understand the problem and how it is caused is invariably missing. To paint in the context requires that we show how apparently isolated facts are linked causally to other social facts; that they are not so isolated after all

AGN Jet Mass Loading and Truncation by Stellar Winds

Active Galactic Nuclei can produce extremely powerful jets. While tightly collimated, the scale of these jets and the stellar density at galactic centers implies that there will be many jet/star interactions, which can mass-load the jet through stellar winds. Previous work employed modest wind mass outflow rates, but this does not apply when mass loading is provided by a small number of high mass-loss stars. We construct a framework for jet mass-loading by stellar winds for a broader spectrum of wind mass-loss rates than has been previously considered. Given the observed stellar mass distributions in galactic centers, we find that even highly efficient (0.1 Eddington luminosity) jets from supermassive black holes of masses M_{BH} \la 10^4M_{\odot} are rapidly mass loaded and quenched by stellar winds. For $10^4 M_{\odot}<M_{BH}<10^8 M_{\odot}$, the quenching length of highly efficient jets is independent of the jet's mechanical luminosity. Stellar wind mass-loading is unable to quench efficient jets from more massive engines, but can account for the observed truncation of the inefficient M87 jet, and implies a baryon dominated composition on scales \ga 2 kpc therein even if the jet is initially pair plasma dominated.Comment: 13 pages, 2 figure

Air Temperature Comparison between the MMTS and the USCRN Temperature Systems

A new U.S. Climate Reference Network (USCRN) was officially and nationally commissioned by the Department of Commerce and the National Oceanic and Atmospheric Administration in 2004. During a 1-yr side-by-side field comparison of USCRN temperatures and temperatures measured by a maximum-minimum temperature system (MMTS), analyses of hourly data show that the MMTS temperature performed with biases: 1) a systematic bias–ambient-temperature-dependent bias and 2) an ambient-solar-radiation- and ambient-wind- speed-dependent bias. Magnitudes of these two biases ranged from a few tenths of a degree to over 1C compared to the USCRN temperatures. The hourly average temperatures for the USCRN were the dependent variables in the development of two statistical models that remove the biases due to ambient temperature, ambient solar radiation, and ambient wind speed in the MMTS. The model performance was examined, and the results show that the adjusted MMTS data were substantially improved with respect to both systematic bias and the bias associated with ambient solar radiation and ambient wind speed. In addition, the results indicate that the historical temperature datasets prior to the MMTS era need to be further investigated to produce long-term homogenous times series of area-average temperature

Effect of Particle-Hole Asymmetry on the Mott-Hubbard Metal-Insulator Transition

The Mott-Hubbard metal-insulator transition is one of the most important problems in correlated electron systems. In the past decade, much progress has been made on examining a particle-hole symmetric form of the transition in the Hubbard model with dynamical mean field theory where it was found that the electronic self energy develops a pole at the transition. We examine the particle-hole asymmetric metal-insulator transition in the Falicov-Kimball model, and find that a number of features change when the noninteracting density of states has a finite bandwidth. Since, generically particle-hole symmetry is broken in real materials, our results have an impact on understanding the metal-insulator transition in real materials.Comment: 5 pages, 3 figure

The Tax Sensitivity of Foreign Direct Investment: Evidence from Firm-Level Panel Data

Understanding the determinants of foreign direct investment (FDI) is important for analyzing capital flows and the industrial organization of multinational firms. Most empirical studies of FDI, however, have focused on case studies of nontax factors in overseas investment decisions or on discerning reduced-form relationships between some measure of FDI and variables relating to nontax and tax aspects of the investment decision. In this paper, we examine the effects of taxation on FDI using previously unexplored (for this purpose) panel data on FDI by subsidiaries of U.S. multinational firms collected by Compustat's geographic segment file project. These firm- level data contain information on new capital investment overseas which enable us to measure tax influences on FDI more precisely and allow us to focus on structural models of subsidiaries' investment decision. Our empirical results cast significant doubt on the simplest notion that 'taxes don't matter' for U.S. firms' FDI decisions. Tax parameters influence FDI in precisely the way indicated by neoclassical models. Our results also lend support to the application of the 'tax capitalization' model to the study of dividend repatriation and foreign direct investment decisions.

Compressibility of the Two-Dimensional infinite-U Hubbard Model

We study the interactions between the coherent quasiparticles and the incoherent Mott-Hubbard excitations and their effects on the low energy properties in the $U=\infty$ Hubbard model. Within the framework of a systematic large-N expansion, these effects first occur in the next to leading order in 1/N. We calculate the scattering phase shift and the free energy, and determine the quasiparticle weight Z, mass renormalization, and the compressibility. It is found that the compressibility is strongly renormalized and diverges at a critical doping $\delta_c=0.07\pm0.01$. We discuss the nature of this zero-temperature phase transition and its connection to phase separation and superconductivity.Comment: 4 pages, 3 eps figures, final version to appear in Phys. Rev. Let

A Theory for the Radius of the Transiting Giant Planet HD 209458b

Using a full frequency-dependent atmosphere code that can incorporate irradiation by a central primary star, we calculate self-consistent boundary conditions for the evolution of the radius of the transiting planet HD 209458b. Using a well-tested extrasolar giant planet evolutionary code, we then calculate the behavior of this planet's radius with age. The measured radius is in fact a transit radius that resides high in HD 209458b's inflated atmosphere. Using our derived atmospheric and interior structures, we find that irradiation plus the proper interpretation of the transit radius can yield a theoretical radius that is within the measured error bars. We conclude that if HD 209458b's true transit radius is at the lower end of the measured range, an extra source of core heating power is not necessary to explain the transit observations.Comment: 6 pages in emulateapj format, plus 2 figures (one color), accepted to the Astrophysical Journa