Phenomenological consequences of supersymmetry with anomaly-induced masses

In the supersymmetric standard model there exist pure gravity contributions to the soft mass parameters which arise via the superconformal anomaly. We consider the low-energy phenomenology with a mass spectrum dominated by the anomaly-induced contributions. In a well-defined minimal model we calculate electroweak symmetry breaking parameters, scalar masses, and the full one-loop splitting of the degenerate Wino states. The most distinctive features are gaugino masses proportional to the corresponding gauge coupling beta-functions, the possibility of a Wino as the lightest supersymmetric particle, mass degeneracy of sleptons, and a very massive gravitino. Unique signatures at high-energy colliders include dilepton and single lepton final states, accompanied by missing energy and displaced vertices. We also point out that this scenario has the cosmological advantage of ameliorating the gravitino problem. Finally, the primordial gravitino decay can produce a relic density of Wino particles close to the critical value.Comment: 26 pages, 7 figures, LaTe

Compositional variation during monogenetic volcano growth and its implications for magma supply to continental volcanic fields

Individual volcanoes of continental monogenetic volcanic fields are generally presumed to erupt single magma batches during brief eruptions. Nevertheless, in two unrelated volcanic fields (the Waipiata volcanic field, New Zealand, and the Miocene-Pliocene volcanic field in western Hungary), we have identified pronounced and systematic compositional differences among products of individual volcanoes. We infer that this indicates a two-stage process of magma supply for these volcanoes. Each volcano records: (1) intrusion of a basanitic parent magma to lower- to mid-crustal levels and its subsequent fractionation to form a tephritic residual melt;, (2) subsequent transection of this reservoir by a second batch of basanitic melt, with tephrite rising to the surface at the head of the propagating basanite dyke. Eruption at the surface then yields initial tephrite, typically erupted as pyroclasts, followed by eruption and shallow intrusion of basanite from deeper in the dyke. By analogy with similar tephrite-basanite eruptions along rift zones of intraplate ocean-island volcanoes, we infer that fractionation to tephrite would have required decades to centuries. We conclude that the two studied continental monogenetic volcanic fields demonstrate a consistent history of early magmatic injections that fail to reach the surface, followed by capture and partial eruption of their evolved residues in the course of separate and significantly later injections of basanite that extend to the surface and erupt. This systematic behaviour probably reflects the difficulty of bringing small volumes of dense, primitive magma to the surface from mantle source regions. Ascent through continental crust is aided by the presence in the dyke head of buoyant tephrite captured during transection of the earlier-emplaced melt bodies

The Lorentz Force and the Radiation Pressure of Light

In order to make plausible the idea that light exerts a pressure on matter, some introductory physics texts consider the force exerted by an electromagnetic wave on an electron. The argument as presented is both mathematically incorrect and has several serious conceptual difficulties without obvious resolution at the classical, yet alone introductory, level. We discuss these difficulties and propose an alternate demonstration.Comment: More or less as in AJ

New York City High-Rises on Rock: Uncovering the Unknown Leads to Variable Foundation Solutions

Construction of high-rise towers in New York City continues to provide exciting challenges for design and construction teams. Sites are becoming increasingly more difficult to build on as “desirable” locations have long since been developed and developers are constructing on sites that were previously over looked. This paper describes two projects that provided unique challenges to the engineers and contractors. The first site is the New York Times Headquarters Tower. This site appeared to be a fairly straightforward foundation design, but became complicated as the subsurface conditions were uncovered. The second case history is the new Bank of America Tower which presented significant design challenges from the outset as it entailed a three basement excavation adjacent to subways and a historic theater façade that required protection. In both cases, close collaboration between the owner, design engineers, construction manager and eventual foundation contractors was required to complete the projects in a timely manner and without adversely affecting adjacent subways, pedestrian traffic, or adjacent historical structures

Times Square Redevelopment: A Below Grade View

The paper describes the design and construction of the foundations for two new high-rise structures in New York City (NYC). The sites are located in the heart of Times Square, bound by 42nd Street to the north, 41st Street to the south, and Broadway to the east. Below grade, active subways and subway stations abut the sites, extending as much as 50 feet into the property. The work involved the demolition of existing structures, excavation of debris and rock to depths exceeding 30 feet below grade, bracing adjacent subway structures around the site, installing high capacity caissons immediately adjacent to the deeper subways, and adapting existing foundations to accommodate the new building foundations. Of particular interest is the preservation of the adjacent historic New Amsterdam Theatre that included vibration and settlement monitoring during construction. Due to the unique site constraints, close collaboration of the Engineers with the Owner, Foundation Contractors, and New York City Transit (NYCT) was required. Innovative solutions for the foundation design were applied to accommodate several construction stages and allowed the projects to be completed without adversely affecting the subways, pedestrian traffic or the historic theatre. The projects received several awards, including the 2001 New York Association of Consulting Engineers (NYACE) Platinum Excellence Award in Geotechnical Engineering and Historical Preservation Plan, and the 2003 NYACE Gold Engineering Excellence Award

A disciplinary commons for database teaching

This paper discusses the experience of taking part in a disciplinary commons devoted to the teaching of database systems. It will discuss the structure of a disciplinary commons and our experience of the database version