Strangeness in Compact Stars and Signal of Deconfinement

Phase transitions in compact stars are discussed including hyperonization, deconfinement and crystalline phases. Reasons why kaon condensation is unlikely is reviewed. Particular emphasis is placed on the evolution of internal structure with spin-down of pulsars. A signature of a first order phase transition in the timing structure of pulsars which is strong and easy to measure, is identified.Comment: 17 pages, 15 figures, Latex. (Invited Talk at the International Symposium on ``Strangeness In Quark Matter 1997'', Thera (Santorini), Hellas, April 14-18, 1997, To be published in Journal of Physics G (Organizers: A Panagiotou and J. Madsen

Dynamic nuclear polarization from current-induced electron spin polarization

Current-induced electron spin polarization is shown to produce nuclear hyperpolarization through dynamic nuclear polarization. Saturated fields of several millitesla are generated upon the application of electric field over a timescale of a hundred seconds in InGaAs epilayers and measured using optical Larmor magnetometry. The dependence on temperature, external magnetic field, and applied voltage is investigated. We find an asymmetry in which the saturation nuclear field depends on the relative alignment of the electrically generated spin polarization and the external magnetic field, which we attribute to an interplay between various electron spin dynamical processes.Comment: 5 pages, 4 figure

On the Physical Origin of OVI Absorption-Line Systems

We present a unified analysis of the O{\sc vi} absorption-lines seen in the disk and halo of the Milky Way, high velocity clouds, the Magellanic Clouds, starburst galaxies, and the intergalactic medium. We show that these disparate systems define a simple relationship between the O{\sc vi} column density and absorption-line width that is independent of the Oxygen abundance over the range O/H $\sim$ 10% to twice solar. We show that this relation is exactly that predicted theoretically as a radiatively cooling flow of hot gas passes through the coronal temperature regime - independent of its density or metallicity (for O/H $\gtrsim$ 0.1 solar). Since most of the intregalactic O{\sc vi} clouds obey this relation, we infer that they can not have metallicities less than a few percent solar. In order to be able to cool radiatively in less than a Hubble time, the intergalactic clouds must be smaller than $\sim$1 Mpc in size. We show that the cooling column densities for the O{\sc iv}, O{\sc v}, Ne{\sc v}, and Ne{\sc vi} ions are comparable to those seen in O{\sc vi}. This is also true for the Li-like ions Ne{\sc viii}, Mg{\sc x}, and Si{\sc xii} (if the gas is cooling from $T \gtrsim 10^6$ K). All these ions have strong resonance lines in the extreme-ultraviolet spectral range, and would be accessible to $FUSE$ at $z \gtrsim$ 0.2 to 0.8. We also show that the Li-like ions can be used to probe radiatively cooling gas at temperatures an order-of-magnitude higher than where their ionic fraction peaks. We calculate that the H-like (He-like) O, Ne, Mg, Si, and S ions have cooling columns of $\sim10^{17}$ cm$^{-2}$. The O{\sc vii}, O{\sc viii}, and Ne{\sc ix} X-ray absorption-lines towards PKS 2155-304 may arise in radiatively cooling gas in the Galactic disk or halo.Comment: 25 pages, 5 figure

Honey bee colony losses

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Chain configurations in light nuclei

The model of nuclear matter built from alpha-particles is proposed. The strong deformed shape for doubly even N=Z nuclides from carbon to magnesium has been determined according to this model. In this paper we undertake very simple approach, which assumes the existence of low lying chain configurations.Comment: 6 pages, 5 figure

The Kentucky Redistricting Problem: Mixed-Integer Programming Model: Working Paper Series--03-04

The goal of the voter-redistricting problem is to partition a state into districts so that the districts have equal populations, are contiguous and compact. Each state has a different variation of this problem due to different state laws, history in the courts and political climate. There has been increasing pressure to remove the partisanship from this process and make it a more technical issue. We focus on the non-political aspects of this problem as defined in the state of Kentucky after the 1990 census. The goal of this redistricting problem is to minimize the number of times that the counties must be divided subject to equal population districts. We present two variations of a mixed-integer programming model. The performance of these models is tested on 12 problems. The tradeoff between the minimum number of cuts and contiguity is examined. Limitations of the models are described