Project HIAM Informal Report, Dec. 1965 - May 1966

Research on planetary atmospheres, Venus dark side emission, ozone concentration, cloud and aerosol scattering, atmospheric radiation scattering, and earth heat budget and albed

Taking Shots at Private Military Firms: International Law Misses its Mark (Again)

Part I of this Article takes a brief tour through military history on the consistent use of mercenaries through the ages, which Peter Singer illuminates masterfully in Corporate Warriors. Next, a brief overview on the binding nature (or not) of international custom and treaty is explored in Part II and then the codifications of international law are taken up in Part III, beginning with the Hague and Geneva Conventions. Several United Nations (“U.N.”) instruments are analyzed for their efficacy in changing the long-standing customary international law on the use of mercenaries and whether or not each is applicable to PMF contractors. Part IV closes out the Article by discussing alternative bodies of domestic law that provide criminal accountability, including the recent case of Alaa Mohammad Ali, a civilian contractor working in Iraq who was convicted on June 23, 2008 by court martial under the recent changes to the Uniform Code of Military Justice (“UCMJ”)

Fundamental Limits on Sensing Chemical Concentrations with Linear Biochemical Networks

Living cells often need to extract information from biochemical signals that are noisy. We study how accurately cells can measure chemical concentrations with signaling networks that are linear. For stationary signals of long duration, they can reach, but not beat, the Berg-Purcell limit, which relies on uniformly averaging in time the fluctuations in the input signal. For short times or nonstationary signals, however, they can beat the Berg-Purcell limit, by non-uniformly time-averaging the input. We derive the optimal weighting function for time averaging and use it to provide the fundamental limit of measuring chemical concentrations with linear signaling networks.Comment: To appear in Physical Review Letters, 7 pages, 4 figure

Reordering of Baryon Chiral Perturbation Theory

Reordering of the chiral perturbation series, proposed recently by Becher and Leutwyler in the framework of SU(2) baryonic ChPT, is applied to the SU(3) case. This results in improved convergence of the chiral expansion of static properties of the lowest lying baryon octet, which in most cases is quite impressive. Finite renormalization of coupling constants and the role it plays in the interpretation of effective field theories is discussed. Some future tests of the viability of the scheme are proposed too.Comment: 9 pages, one reference adde

The thermodynamics of computational copying in biochemical systems

Living cells use readout molecules to record the state of receptor proteins, similar to measurements or copies in typical computational devices. But is this analogy rigorous? Can cells be optimally efficient, and if not, why? We show that, as in computation, a canonical biochemical readout network generates correlations; extracting no work from these correlations sets a lower bound on dissipation. For general input, the biochemical network cannot reach this bound, even with arbitrarily slow reactions or weak thermodynamic driving. It faces an accuracy-dissipation trade-off that is qualitatively distinct from and worse than implied by the bound, and more complex steady-state copy processes cannot perform better. Nonetheless, the cost remains close to the thermodynamic bound unless accuracy is extremely high. Additionally, we show that biomolecular reactions could be used in thermodynamically optimal devices under exogenous manipulation of chemical fuels, suggesting an experimental system for testing computational thermodynamics.Comment: Accepted versio

Pla d'acció per a la igualtat d'oportunitats per a les persones amb discapacitat a la Universitat Autònoma de Barcelona 2011-2015 : aprovat pel Consell de Govern en la sessió del 17 de novembre de 2010

El propòsit és agrupar en un sol document el conjunt d'iniciatives que fins ara es duen a terme i que es volen endegar, alhora que s'assumeix com a responsabilitat institucional la inclusió de les persones amb discapacitat, amb l'objectiu de fer de la nostra comunitat un espai inclusiu, una aspiració esmentada en els nostres estatuts i en el Pla director

Vortex nucleation in bose-einstein condensates due to effective magnetic fields

We investigate the rotational properties of a Bose-Einstein condensate (BEC) in an effective magnetic field. The corresponding gauge potential is optically generated, and based on the adiabatic motion of the atoms. We demonstrate that the nucleation of vortices is seeded by instabilities in surface excitations and show that this picture also holds when the applied effective magnetic field is not homogeneous. The eventual configuration of vortices in the cloud depends on the geometry of the applied field