Superstring Relics, Supersymmetric Fragmentation and UHECR

Superstring theory predicts the existence of relic metastable particles whose average lifetime is longer than the age of the universe and which could, in principle, be good dark matter candidates. At the same time, these states would be responsible for the Ultra High Energy Cosmic Rays (UHECR) events which will be searched for by various experimental collaborations in the near future. We describe a possible phenomenological path which could be followed in order to search for new physics in their detection.Comment: 7 pages 4 Figs. Plenary Talk presented by Claudio Coriano' at the 1st Intl. Conf. on String Phenomenology, Oxford, UK, July 6-11, 200

Nuclear re-interaction effects in quasi-elastic neutrino nucleus scattering

The quasi-elastic neutrino-nucleus cross section has been calculated by using a Fermi gas model corrected to consider the re-scattering between the emitted nucleon and the rest nucleus. As an example of the relevance of this effect we show results for the muon production cross section on 16O target.Comment: 7 pages, 4 Postscript figures, Contribution to NuInt01 Workshop, KEK, Tsukuba, Japa

Controlled Ecological Life Support Systems: CELSS 1985 Workshop

Various topics related to closed ecological systems are discussed. Space habitats, vegetative growth, photosynthesis, recycling, culture techniques, waste utilization bioreactors and controlled atmospheres on space stations are among the topics covered

Identification of Showers with Cores Outside the ARGO-YBJ Detector

In any EAS array, the rejection of events with shower cores outside the detector boundaries is of great importance. A large difference between the true and the reconstructed shower core positions may lead to a systematic miscalculation of some shower characteristics. Moreover, an accurate determination of the shower core position for selected internal events is important to reconstruct the primary direction using conical fits to the shower front, improving the detector angular resolution, or to performe an efficient gamma/hadron discrimination. In this paper we present a procedure able to identify and reject showers with cores outside the ARGO-YBJ carpet boundaries. A comparison of the results for gamma and proton induced showers is reported.Comment: 4 pages, to be published in the Proceedings of the 28th International Cosmic Ray Conference (Tsukuba, Japan 2003

Expected sensitivity of ARGO-YBJ to detect point gamma-ray sources

ARGO-YBJ is a full coverage air shower detector currently under construction at the Yangbajing Laboratory (4300 m a.s.l., Tibet, China). First data obtained with a subset of the apparatus will be available in summer 2003 while the full detector operation is expected in 2005. One of the main aims of ARGO-YBJ is the observation of gamma-ray sources, at an energy threshold of a few hundreds GeV. In this paper we present the expected sensitivity to detect point gamma ray sources, with particular attention to the Crab Nebula. According to our simulations a Crab-like signal could be detected in one year of operation with a statistical significance of 10 standard deviations, without any gamma/hadron discrimination.Comment: 4 pages, 2 Postscript figure

Two-season agriculture and irrigated rice during the Dian: radiocarbon dates and archaeobotanical remains from Dayingzhuang, Yunnan, Southwest China

Historical sources describe irrigation and intensive agriculture being practiced in lowland Yunnan from at least the first century AD, but so far archaeobotanical remains allowing investigation of this issue have been scarce. Here, we present new archaeobotanical evidence, including macro-botanical and phytoliths results, from the Dian settlement site of Dayingzhuang, with direct AMS radiocarbon dates on two wheat grains falling between 750 and 390 BC. We compare these results with contemporary Dian sites and analyse the agricultural systems in Central Yunnan between the eight and fourth centuries BC. We propose that agriculture was intensified toward the end of the Dian through both multiple cropping seasons and increased evidence for irrigated rice fields.Introduction The site of Dayingzhuang - Environment and excavation - Chronometric results: dates and sequences - Site description and material culture -- Features -- Ceramics -- Stone and other implements -- Metal objects -- Faunal remains Materials and methods - Macro-botanical remains - Phytolith remains Results - Macro-botanical remains -- General features of the assemblage and key economic taxa -- Cereal crops -- Wheat and barley -- Rice -- Millets -- Chenopodium -- Other possible cultigens -- Seeds of field weed species - Phytoliths remains: general features - Rice cultivation ecology: inferences from phytoliths Discussion: characterizing Dian agriculture Conclusio

Cellular cholesterol and how to find it

Cholesterol is an essential component of eukaryotic cellular membranes. Information about its subcellular localization and transport pathways inside cells are key for the understanding and treatment of cholesterol-related diseases. In this review we give an overview over the most commonly used methods that contributed to our current understanding of subcellular cholesterol localization and transport routes. First, we discuss methods that provide insights into cholesterol metabolism based on readouts of downstream effects such as esterification. Subsequently, we focus on the use of cholesterol-binding molecules as probes that facilitate visualization and quantification of sterols inside of cells. Finally, we explore different analogues of cholesterol which, when taken up by living cells, are integrated and transported in a similar fashion as endogenous sterols. Taken together, we highlight the challenges and advantages of each method such that researchers studying aspects of cholesterol transport may choose the most pertinent approach for their problem

The Networked Common Goods Game

We introduce a new class of games called the networked common goods game (NCGG), which generalizes the well-known common goods game. We focus on a fairly general subclass of the game where each agent's utility functions are the same across all goods the agent is entitled to and satisfy certain natural properties (diminishing return and smoothness). We give a comprehensive set of technical results listed as follows. * We show the optimization problem faced by a single agent can be solved efficiently in this subclass. The discrete version of the problem is however NP-hard but admits an fully polynomial time approximation scheme (FPTAS). * We show uniqueness results of pure strategy Nash equilibrium of NCGG, and that the equilibrium is fully characterized by the structure of the network and independent of the choices and combinations of agent utility functions. * We show NCGG is a potential game, and give an implementation of best/better response Nash dynamics that lead to fast convergence to an $\epsilon$-approximate pure strategy Nash equilibrium. * Lastly, we show the price of anarchy of NCGG can be as large as $\Omega(n^{1-\epsilon})$ (for any $\epsilon>0$), which means selfish behavior in NCGG can lead to extremely inefficient social outcomes

Enhanced magnetic response of fluids using self-assembled petal-like iron oxide particles

Using self-assembled iron oxide (SAIO) particles with petal-like morphology, aqueous fluids containing magnetic particles were prepared and the effect of hierarchical particle surface on the viscoelasticity under magnetic was investigated. The fluids consisting of self-assembled iron oxide particles exhibit highly tunable viscoelasticity which is controlled by applying external magnetic field. A difference between SAIO particles and spherical particles is explained by the fact that surface features of the self-assembled particles increased the network strength between particles in the fluids. © 2010 American Institute of Physics