Review of SIS Experimental Results on Strangeness

>A review of meson emission in heavy ion collisions at incident energies around 1 -- 2 $A\cdot$GeV is presented. It is shown how the shape of the spectra and the various particle yields vary with system size, with centrality and with incident energy. A statistical model assuming thermal and chemical equilibrium and exact strangeness conservation (i.e. strangeness conservation per collision) explains most of the observed features. Emphasis is put onto the study of $K^+$ and $K^-$ emission. In the framework of this statistical model it is shown that the experimentally observed equality of $K^+$ and $K^-$ rates at threshold corrected energies $\sqrt{s} - \sqrt{s_{th}}$ is due to a crossing of two excitation functions. Furthermore, the independence of the $K^+$ to $K^-$ ratio on the number of participating nucleons observed between 1 and 10 $A\cdot$GeV is consistent with this model. The observed flow effects are beyond the scope of this model.Comment: 10 pages, 9 figures, Strangeness 2000, V International Conference on Strangeness in Quark Matter, July, 2000, Berkeley, Californi

Image retrieval by hypertext links

This paper presents a model for retrieval of images from a large World Wide Web based collection. Rather than considering complex visual recognition algorithms, the model presented is based on combining evidence of the text content and hypertext structure of the Web. The paper shows that certain types of query are amply served by this form of representation. It also presents a novel means of gathering relevance judgements

Curvature-controlled defect dynamics in active systems

We have studied the collective motion of polar active particles confined to ellipsoidal surfaces. The geometric constraints lead to the formation of vortices that encircle surface points of constant curvature (umbilics). We have found that collective motion patterns are particularly rich on ellipsoids, with four umbilics where vortices tend to be located near pairs of umbilical points to minimize their interaction energy. Our results provide a new perspective on the migration of living cells, which most likely use the information provided from the curved substrate geometry to guide their collective motion.Comment: Accepted manuscript. 8 pages, 7 Figures. Movies of the motion patterns can be found at https://www.youtube.com/playlist?list=PLEsE7_tnqXZ_U258VwxES8KAJTV_eO43

Goats - nutrition and feeding

The nutritional needs of goats are similar to those of sheep. They both require energy, protein, vitamins, minerals and water to survive and be productive. For optimum performance these nutrients should be supplied constantly and in relatively fixed proportions. An excess of protein, vitamins or minerals will not make up for a shortfall in energy, nor will a shortfall in protein, vitamins or minerals be made up by an excess of energy. Goats\u27 nutrient requirements depend on their size, whether the goat is pregnant, lactating, growing or just maintaining body functions.https://researchlibrary.agric.wa.gov.au/bulletins/1258/thumbnail.jp

Multiplexed communication over a high-speed quantum channel

In quantum information systems it is of particular interest to consider the best way in which to use the non-classical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are amongst the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analogue bandwidth. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4 GHz comb of vacuum squeezing produced by a sub-threshold OPO, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel

The Role of Starbursts in the Formation of Galaxies & Active Galactic Nuclei

Starbursts are episodes of intense star-formation in the central regions of galaxies, and are the sites of roughly 25% of the high-mass star-formation in the local universe. In this contribution I review the role starbursts play in the formation and evolution of galaxies, the intergalactic medium, and active galactic nuclei. Four major conclusions are drawn. 1) Starburst galaxies are good analogues (in fact, the only plausible local analogues) to the known population of star-forming galaxies at high-redshift. 2) Integrated over cosmic time, supernova-driven galactic-winds (`superwinds') play an essential role in the evolution of galaxies and the inter-galactic medium. 3) Circumnuclear starbursts are an energetically-significant component of the Seyfert phenomenon. 4) The evolution of the population of the host galaxies of radio-quiet quasars is significantly different than that of powerful radio galaxies, and is at least qualitatively consistent with the standard picture of the hierarchical assembly of massive galaxies at relatively late times.Comment: 16 pages, 4 figures, Royal Society discussion meeting `The formation of galaxies