Attainability in Repeated Games with Vector Payoffs

We introduce the concept of attainable sets of payoffs in two-player repeated games with vector payoffs. A set of payoff vectors is called {\em attainable} if player 1 can ensure that there is a finite horizon $T$ such that after time $T$ the distance between the set and the cumulative payoff is arbitrarily small, regardless of what strategy player 2 is using. This paper focuses on the case where the attainable set consists of one payoff vector. In this case the vector is called an attainable vector. We study properties of the set of attainable vectors, and characterize when a specific vector is attainable and when every vector is attainable.Comment: 28 pages, 2 figures, conference version at NetGCoop 201

The mechanism of halogen liberation in the polar troposphere

International audienceSudden depletions of tropospheric ozone during spring were reported from the Arctic and also from Antarctic coastal sites. Field studies showed that those depletion events are caused by reactive halogen species, especially bromine compounds. However the source and seasonal variation of reactive halogen species is still not completely understood. There are several indications that the halogen mobilisation from the sea ice surface of the polar oceans may be the most important source for the necessary halogens. Here we present a 1-D model study aimed at determining the primary source of reactive halogens. The model includes gas phase and heterogeneous bromine and chlorine chemistry as well as vertical transport between the surface and the top of the boundary layer. The autocatalytic Br release by photochemical processes (bromine explosion) and subsequent rapid bromine catalysed ozone depletion is well reproduced in the model and the major source of reactive bromine appears to be the sea ice surface. The sea salt aerosol alone is not sufficient to yield the high levels of reactive bromine in the gas phase necessary for fast ozone depletion. However, the aerosol efficiently 'recycles' less reactive bromine species (e.g. HBr) and feeds them back into the ozone destruction cycle. Isolation of the boundary layer air from the free troposphere by a strong temperature inversion was found to be critical for boundary layer ozone depletion to happen. The combination of strong surface inversions and presence of sunlight occurs only during polar spring

Portrait of a people: the Jewish Heritage Collection dedicated to Mark and Dave Harris

The Jewish Heritage Collection was a gift made jointly to the Frankel Center for Judaic Studies and the University Library, which aptly reflects the comprehensive and unique nature of this collection. This collection combines materials traditionally found in libraries (e.g., books, pamphlets, printed ephemera, and manuscripts) with objects of museum quality (artwork and historical artifacts) and an assortment of items of humbler nature used in everyday life. The curators have chosen several themes around which to organize the display, in order to demonstrate both interesting items from the collection and topics for study it can easily support. The full Portrait of a People Online Exhibit follows a brief biography of Constance Harris and an excerpt from her book, The Way Jews Lived. as well as essays on how the collection was assembled and how it will be used written by the Elliot Gertel and Erica Lehrer.Special Collections Libraryhttp://deepblue.lib.umich.edu/bitstream/2027.42/108167/1/Portrait-of-a-people.pd

theta-Defensins: Cyclic Peptides with Endless Potential

theta-Defensins, the only cyclic peptides of animal origin, have been isolated from the leukocytes of rhesus macaques and baboons. Their biogenesis is unusual because each peptide is an 18-residue chimera formed by the head-to-tail splicing of nonapeptides derived from two separate precursors. theta-Defensins have multiple arginines and a ladder-like tridisulfide array spanning their two antiparallel beta-strands. Human theta-defensin genes contain a premature stop codon that prevents effective translation of the needed precursors; consequently, these peptides are not present in human leukocytes. Synthetic theta-defensins with sequences that correspond to those encoded within the human pseudogenes are called retrocyclins. Retrocyclin-1 inhibits the cellular entry of HIV-1, HSV, and influenza A virus. The rhesus theta-defensin RTD-1 protects mice from an experimental severe acute respiratory syndrome coronavirus infection, and retrocyclin- 1 protects mice from infection by Bacillus anthracis spores. The small size, unique structure, and multiple host defense activities of theta-defensins make them intriguing potential therapeutic agents

Orientational order on curved surfaces - the high temperature region

We study orientational order, subject to thermal fluctuations, on a fixed curved surface. We derive, in particular, the average density of zeros of Gaussian distributed vector fields on a closed Riemannian manifold. Results are compared with the density of disclination charges obtained from a Coulomb gas model. Our model describes the disordered state of two dimensional objects with orientational degrees of freedom, such as vector ordering in Langmuir monolayers and lipid bilayers above the hexatic to fluid transition.Comment: final version, 13 Pages, 2 figures, uses iopart.cl

Globalisation and the ethics of transnational biobank networks

Biobanks are increasingly being linked together into global networks in order to maximise their capacity to identify causes of and treatments for disease. While there is great optimism about the potential of these biobank networks to contribute to personalised and data-driven medicine, there are also ethical concerns about, among other things, risks to personal privacy and exploitation of vulnerable populations. Concepts drawn from theories of globalisation can assist with the characterisation of the ethical implications of biobank networking across borders, which can, in turn, inform more ethically sophisticated responses. Using the China Kadoorie Biobank as a case study, we show how distinguishing between the subnational, transnational, supranational and extranational spheres of operation and influence can help researchers, institutions and regulators to understand and manage the ethical issues raised by the globalisation of biobanking.National Health and Medical Research Council (Australia

Repeated games over networks with vector payoffs: the notion of attainability.

We introduce the concept of strongly attainable sets of payoffs in two-player repeated games with vector payoffs in continuous time. A set of payoffs is called strongly attainable if player 1 has a strategy guaranteeing, even in the worst case, that the distance between the set and the cumulative payoff shrinks with time to zero. We characterize when any vector is strongly attainable and illustrate the motivation of our study on a multiinventory application