Microlensing By a Prolate All-Macho Halo

It is widely believed that dark matter halos are flattened, that is closer to oblate than prolate. The evidence cited is based largely on observations of galaxies which do not look anything like our own and on numerical simulations which use ad hoc initial conditions. Given what we believe to be a ``reasonable doubt'' concerning the shape of dark Galactic halo we calculate the optical depth and event rate for microlensing of stars in the LMC assuming a wide range of models that include both prolate and oblate halos. We find, in agreement with previous analysis, that the optical depth for a spherical (E0) halo and for an oblate (E6) halo are roughly the same, essentially because two competing effects cancel approximately. However the optical depth for an E6 prolate halo is reduced by ~35%. This means that an all-Macho prolate halo with reasonable parameters for the Galaxy is consistent with the published microlensing event rate.Comment: 7 pages (24K), LaTeX; 2 Postscript figure

Competing interactions of spin and lattice in the Kondo lattice model

The magnetic properties of a system of coexisting localized spins and conduction electrons are investigated within an extended version of the one dimensional Kondo lattice model in which effects stemming from the electron-lattice and on-site Coulomb interactions are explicitly included. After bosonizing the conduction electrons, is it observed that intrinsic inhomogeneities with the statistical scaling properties of a Griffiths phase appear, and determine the spin structure of the localized impurities. The appearance of the inhomogeneities is enhanced by appropriate phonons and acts destructively on the spin ordering. The inhomogeneities appear on well defined length scales, can be compared to the formation of intrinsic mesoscopic metastable patterns which are found in two-fluid systems.Comment: 9 pages, to appear in Jour. Superconductivit

Energy, Shading and Daylighting Analysis for the Austin Bergstrom International Airport Terminal

Our firm was under contract with the City of Austin, Texas to perform energy analysis and analysis of the daylighting potential within the New Austin Bergstrom International Airport Terminal. Design of the Passenger Terminal Facility for the New Austin Airport included large glass areas for viewing arriving and departing planes, the sky, and the surrounding terrain. The glass was envisioned to provide quality natural lighting for the terminal during daylight hours in order to improve the quality of the space and save energy throughout the usable life of the terminal. For the glass to achieve the design goals, adverse qualities were minimized and beneficial qualities must be enhanced. Using computer simulation, we studied the shading devices on the south clearstories to maximize the daylight and minimize problems of direct gain in a large commercial space. The study also included analysis of skylights above the baggage claim, indirect lighting of major spaces within the airport, and the controls of the artificial lights for integrating the efficient use of the available daylight. The energy, shading, and daylighting analysis includes analysis of a mix of low and high volume spaces. The daylight sources include glass walls, clearstories, and skylights

Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to Five-, Six-, and Seven-Membered β-Substituted Cyclic Enones: Enantioselective Construction of All-Carbon Quaternary Stereocenters

The first enantioselective Pd-catalyzed construction of all-carbon quaternary stereocenters via 1,4-addition of arylboronic acids to β-substituted cyclic enones is reported. Reaction of a wide range of arylboronic acids and cyclic enones using a catalyst prepared from Pd(OCOCF_3)_2 and a chiral pyridinooxazoline ligand yields enantioenriched products bearing benzylic stereocenters. Notably, this transformation is tolerant to air and moisture, providing a practical and operationally simple method of synthesizing enantioenriched all-carbon quaternary stereocenters

An LED-based Flasher System for VERITAS

We describe a flasher system designed for use in monitoring the gains of the photomultiplier tubes used in the VERITAS gamma-ray telescopes. This system uses blue light-emitting diodes (LEDs) so it can be operated at much higher rates than a traditional laser-based system. Calibration information can be obtained with better statistical precision with reduced loss of observing time. The LEDs are also much less expensive than a laser. The design features of the new system are presented, along with measurements made with a prototype mounted on one of the VERITAS telescopes.Comment: Accepted for publication in Nuclear Instruments and Methods in Physics Research

Resolving the Post-Begay Maelstrom Statutory Rape as a Violent Felony Under the Armed Career Criminal Act

The Armed Career Criminal Act ( ACCA ), enacted in 1984, mandates a minimum fifteen-year sentence for defendants who unlawfully possess a firearm and who also have three prior convictions for violent felonies and/or serious drug offenses. Since its inception, the ACCA has presented a weighty problem: what constitutes a violent felony? The United States Supreme Court has made an effort to allay the confusion, most recently in its decision in Begay v. United States, requiring that violent felonies be purposefully violent or aggressive. This Note questions the reasoning of circuit courts that have disallowed statutory rape as a violent felony post-Begay, a stance that has generally been supported by the argument that, as a strict liability crime that is often consensual, a statutory rape cannot be uniformly typified as purposeful or aggressive. Rather than construing the acquiescence of a minor to intercourse as consent that negates the aggression required under Begay, the focus of the courts should instead be on the reason that the legislatures in all states have rendered sex with a minor a strict liability crime: a child lacks the ability to give any legally-cognizable consent. This well-settled rule of law should create a presumption that, if an adult knowingly engages in sexual intercourse with a minor below the age of consent, such intercourse is inevitably the result of a purposeful aggression against the child on the part of the offender. Such a presumption is implied by the nature of the crime itself and by the manner in which the states have drafted their statutory rape legislation. Adopting this rule would remedy the post-Begay confusion with regards to strict liability sex crimes that center on the inability of the victims to form consent. In furtherance of this view, Part II of this Note seeks to define statutory rape in light of how the elements differ by jurisdiction. Part III explores the legislative history of the ACCA\u27s enhanced sentencing provisions and its definition of violent felonies for the purpose of enhanced sentencing, and compares this language to that of other federal sentencing guidelines. Part IV describes the United States Supreme Court rulings in Begay v. United States and Chambers v. United States and how these cases have contributed to the ongoing evolution of the definition of a violent felony or a crime of violence. Part V examines statutory rape as a predicate violent felony and proposes a rule that would, in accordance with Begay, presume aggression in the absence of consent. Part VI considers the serious risks of physical harm to minors that may result from sexual activity with an adult offender, and why these risks should render statutory rape a predicate violent felony under the ACCA. Part VII concludes

Constitutional Law - Fifth Amendment Due Process - Sex Discrimination - Suspect Classification

In a plurality opinion, the United States Supreme Court has held that classifications based on sex violate due process guarantees where female, and not male, members of the armed services are required to prove dependency of their spouses as a condition for receiving benefits. Frontiero v. Richardson, 411 U.S. 677 (1973)