From Railroads to Sand Dunes: An Examination of the Offsetting Doctrine in Partial Takings

Called “shadowy at best,” the offsetting doctrine in partial takings has confused “even trained legal minds” and generated inconsistent decision after inconsistent decision. The offsetting doctrine allows certain benefits, termed special, to offset condemnation awards, while general benefits may not be offset. Courts blindly adhere to the doctrine despite its underpinnings rooted in eighteenth-century public policy, which was based on concerns of overly speculative valuation and arguably erroneous fairness, as well as incorrect interpretations of Takings Clause jurisprudence. Such adherence dramatically increases the cost of financing a takings project. In the face of blind adherence to the doctrine, municipalities are forced to balance the needs of their citizens against the needs of eighteenth-century courts, often resulting in the failure of municipalities to engage in takings for the public benefit. This Note argues that new public policy concerns warrant rejection of the doctrine in favor of a rule that allows all nonspeculative benefits to offset a condemnation award. This rule would take into account modern advances in evidence, promote fairness, simplify the judicial process, and allow municipalities to respond to twentieth-century problems while landowners receive just compensation for taken land

An investigation of the optical absorption properties of silicon as related to its electrical conductivity

The purpose of this study is to demonstrate the feasibility of obtaining the electrical conductivity of band gap semiconductors, by considering the absorption of radiation in the visible region. The experimental evidence confirmed predictions that the conductivities of the silicon samples are related to the horizontal displacement of energy in the absorption curves. The material used in this study was p-doped silicon, although the approach should be valid in general for either elemental or compound semiconductors. The absorption coefficient for silicon was measured in the radiation region between 2.0 and 3.0 ev. This region above the indirect band gap (= 1.1 ev) is where the absorption coefficient is significant (order of 105 cm-1), consequently, a reflectance method was considered most appropriate to measure the absorption. Measurements were made on p-doped silicon wafers differing by four orders of magnitude. The nominal values of the resistivities as determined by four point probe measurements were from 0.005 ohm-cm to 50 ohm-cm. Maxwell\u27s equations are applied for a plane electromagnetic wave propagating in an absorbing, homogeneous, linear medium. The resulting solutions lead to expressions for the real refractive index, nr, and the extinction coefficient, k. The amount of absorption of radiation in the medium is defined in terms of the absorption coefficient, α, which is directly proportional to k and inversely proportional to the wavelength, λ. The value for k as a function of wavelength was measured using a non-normal incidence reflectance method in which the pseudo-polar izing angle was measured. A Bausch and Lomb Grating Monochromator and a Tungsten light source was used for the monochromatic source (±1Å at the 50% intensity points). The incident monochromatic light beam was collimated, chopped mechanically by a chopper wheel to produce 3600 HZ, and then reflected from a silicon wafer. The wafer was mounted on a turn-table designed so that the reflected and incident angles were equal to better then five minutes of arc. The reflected light which was elliptically polarized was measured by a photomultiplier assembly. The amplitude of the reflected components in and normal to the plane of incidence was determined by a good grade of polarizer mounted before the photomultiplier entrace slit. Expressions are given which show that only the polarizing angle, θp, and the amplitude ratio of reflected components, are necessary to determine k and nr. Two theoretical models were assumed in an effort to fit the experimental data. The first attempt was on a semi-classical model in which the charge carriers were considered to be bound elastically with damping to account for dissipation due to collisions. The model, through a proper choice of the damping constants is found to be a reasonable fit to the absorption curve, but only for the region from 2.0 to 2.5 ev. The quantum mechanical approach was, as expected, by far the better of the two models chosen. The experimental absorption coefficient curve had the same general shape as the ideal quantum mechanical curve, but higher by an order of magnitude. This discrepancy is explained by the presence of a surface oxide layer and the fact that the quantum mechanical curve was based on an ideal semiconductor. The absorption coefficient is found to vary as the square of the radiation energy in excess of the indirect band gap, for the entire region between 2.0 and 3.0 ev. There was no evidence that the absorption process was due to direct transitions, even for energies near 3.0 ev. Expressions are derived which indicate that the ratio of two low frequency electrical conductivities are dependent on the effective band shrinkage due to doping and the Fermi level shift. The conductivity σ2 can be determined by comparing its absorption curve with that of a known al. This is realized by using the horizontal energy displacement between the two curves, ΔEd, in the derived expression. Further data taken on clean (etched surfaces) silicon wafers did indicate that direct transitions occurred consistently at 2.48 ev

Trace anomaly and Hawking effect in 2D dilaton gravity theories

We investigate the classical and semiclassical features of generic 2D, matter-coupled, dilaton gravity theories. In particular, we show that the mass, the temperature and the flux of Hawking radiation associated with 2D black holes are invariant under dilaton-dependent Weyl rescalings of the metric. The relationship between quantum anomalies and Hawking radiation is discussed.Comment: 4 pages, LaTex file uses espcrc2.sty, Talk given at the Second Conference on Constrained Dynamics and Quantum Gravity, Santa Margherita Ligure, Italy, September 1996, to appear in the Proceeding

Cross-Dictionary Linking at Sense Level with a Double-Layer Classifier

We present a system for linking dictionaries at the sense level, which is part of a wider programme aiming to extend current lexical resources and to create new ones by automatic means. One of the main challenges of the sense linking task is the existence of non one-to-one mappings among senses. Our system handles this issue by addressing the task as a binary classification problem using standard Machine Learning methods, where each sense pair is classified independently from the others. In addition, it implements a second, statistically-based classification layer to also model the dependence existing among sense pairs, namely, the fact that a sense in one dictionary that is already linked to a sense in the other dictionary has a lower probability of being linked to a further sense. The resulting double-layer classifier achieves global Precision and Recall scores of 0.91 and 0.80, respectively

Exact Path Integral Quantization of Generic 2-D Dilaton Gravity

Local path integral quantization of generic 2D dilaton gravity is considered. Locality means that we assume asymptotic fall off conditions for all fields. We demonstrate that in the absence of `matter' fields to all orders of perturbation theory and for all 2D dilaton theories the quantum effective action coincides with the classical one. This resolves the apparent contradiction between the well established results of Dirac quantization and perturbative (path-integral) approaches which seemed to yield non-trivial quantum corrections. For a particular case, the Jackiw--Teitelboim model, our result is even extended to the situation when a matter field is present.Comment: 15 page

Nonperturbative path integral of 2d dilaton gravity and two-loop effects from scalar matter

Performing an nonperturbative path integral for the geometric part of a large class of 2d theories without kinetic term for the dilaton field, the quantum effects from scalar matter fields are treated as a perturbation. When integrated out to two-loops they yield a correction to the Polyakov term which is still exact in the geometric part. Interestingly enough the effective action only experiences a renormalization of the dilaton potential.Comment: 15 page

Formation and Evaporation of a Naked Singularity in 2D Gravity

We describe a classical configuration of conformal matter forming a naked singularity and discuss its subsequent Hawking evaporation within the context of two dimensional dilaton gravity. The one loop analysis is credible for a large mass naked singularity and suggests the existence of a weak cosmological censorship that would cause it to explode into radiation upon forming. (Hardcopies of figures available on request)Comment: 10 pages, PHYZZX, preprint UATP-93/0

Two-Dimensional Reduced Theory and General Static Solution for Uncharged Black p-Branes

We derive a two-dimensional effective dilaton - gravity - matter action that describes the dynamics of an uncharged black p-brane in N dimensions. We show that this effective theory is completely integrable in the static sector and establish its general static solution. The solution includes, as a particular case, the boost symmetric p-brane solution investigated in hep-th/9510202 .Comment: 11 pages, plain LaTex, accepted for publication in Phys. Lett.

2D quantum dilaton gravitational Hamiltonian, boundary terms and new definition for total energy

The ADM and Bondi mass for the RST model have been first discussed from Hawking and Horowitz's argument. Expressing the localized RST action in terms of the ADM formulation, the RST Hamiltonian can be derived, meanwhile keeping track of all boundary terms. Then the total boundary terms can be taken as the total energy for the RST model. It has been found that there is a new contribution to the ADM and Bondi mass from the RST boundary due to the existence of the hidden dynamical field. The ADM and Bondi mass have been discussed respectively in detail, and some new properties have been found.Comment: 14 pages, Latex file, no figure, to appear in Phys. Lett.

Generalized symmetries and invariant matter couplings in two-dimensional dilaton gravity

New features of the generalized symmetries of generic two-dimensional dilaton models of gravity are presented and invariant gravity-matter couplings are introduced. We show that there is a continuum set of Noether symmetries, which contains half a de Witt algebra. Two of these symmetries are area-preserving transformations. We show that gravity-matter couplings which are invariant under area preserving transformations only contribute to the dynamics of the dilaton-gravity sector with a reshaping of the dilaton potential. The interaction with matter by means of invariant metrics is also considered. We show in a constructive way that there are metrics which are invariant under two of the symmetries. The most general metrics and minimal couplings that fulfil this condition are found.Comment: LateX file, no macros, 14pp: minor changes have been made and some misprints have been correcte