THE COMMUNITy AND SCHOOL DESEGREGATION: THE SEARCH FOR HOUSING MARKET EFFECTS

This paper attempts to measure the effect of a court-ordered desegregation plan on three aspects of the housing market in Dallas County, Texas. The indicators include sale price, number of sales, and proportion of home sales financed by conventional mortgages. Monthly data from 1969 to 1979 are analyzed using Box-Jenkins time series models. After best fit models are determined, various intervention terms are introduced into the models to assess the impact of both a 1975 Circuit Court Order and a 1976 District Court Order. The analysis suggests neither order had a measurable effect on the housing market in Dallas.     

STAyING ALIVE: STREET TREE SURVIVAL IN THE INNER-CITy1

A study was conducted from 1978 to late 1984 of the survival of inner-city street trees planted by the Oakland, California urban forestry program. The tree survival rate of approximately 60 to 70 percent from the trees planted in neighborhood parkways through urban forestry sponsored block parties contrasted sharply with less than one percent survival of trees planted earlier by the Model Cities program without community participation or ceremonial plantings. Explanations for the high tree survival were tested using participant observation, interviews with residents, and a small panel. Tree survival was not found to be related to the explanations provided by urban forestry ideology; namely, that residents had been educated to hold both instrumental and expressive values toward trees. Rather, the explanation appeared to be the function of an unintended solution to the issue of parkway ownership. The tree planting process which included species selection meetings and tree planting ceremonies tended to define the parkway trees as a resident's property, thus decreasing the significance of the parkway-property barrier. The generality of the Oakland illustration is discussed.     

Immobilized α-amylase from Bacillus licheniformis: a potential enzymic time—temperature integrator for thermal processing

Biphasic and nth-order models were tested as to their usefulness to fit experimental inactivation data of Bacillus licheniformis α-amylase, immobilized on glass beads, and were discussed with respect to their suitability to characterize the considered enzymic system as a time—temperature integrator (TTI) to evaluate heat processes. Both isothermal and non-isothermal inactivation experiments were carried out. Model (kinetic) parameters (rate constant k, activation energy E_A and reaction order n) were estimated using a non-linear regression procedure. The results obtained, especially the activation energy of about 293 kJ mole^–1, indicated a potential use of this system as a TTI for heating processes in the temperature range of 96–108°C.     

Structural Aspects of the Lattice Thermal Expansion of Hexagonal Cordierite

The mechanism of lattice thermal expansion in pure hexagonal cordierite prepared by glass devitrification was investigated by time-of-flight neutron powder diffraction at temperatures from 22° to 750°C under vacuum. Full matrix least-squares refinement of the diffraction spectra was carried out in space group P6/mcc using the Rietveld method. The structural data from the refinements were resolved into components parallel and normal to the c axis. The negative c axis expansion results from two effects: (1) increasing distortion of the T₂ tetrahedral (ring tetrahedra) with temperature, primarily due to displacement of the T₂ cations toward the c-axis channels in the structure; (2) decreasing distortion of the T₁/M tetrahedra/ octahedra with increasing temperature, due to octahedral I (M-O₁) bond expansion and an associated decrease in torsional distortion of the T₁ tetrahedra.     

Inverse Spinel Pigments

The system Zn₂TiO₄-Co₂TiO₄-Ni₂TiO₄ yields a bright green pigment with the orthotitanate spinel structure. Brick-red, orange, and brown pigments are found in the system Zn₂TiO₄-Co₂TiO₄-Ni₂TiO₄.     

On joining non-singular and singular optimal control subarcs

Necessary conditions for junctions between non-singular and singular optimal control subarcs are proved for the case where the singular problem order is greater than one. the generalized Legendre-Clebsch condition (GLC) vanishes at the junction, and the derivative of the GLC expression is non-zero at the junction. The proof requires the derivation of two identities which are system properties of higher-order singular problems     

Review Article Remote sensing methodologies and geography

Abstract

Remote sensing is a technique used in scientific and technological approaches to geographical research. In the scientific approaches (of which the empirical are the most popular) the motivation is curiosity, the goal is knowledge and the methodology is often induction to derive theory and then deduction to verify theory. In the technological approaches the motivation is human need, the goal is the application of knowledge and the methodology is design. This review discusses both approaches, concentrating on the problems of taking a scientific approach and the unwillingness of geographers to accept an often more suitable technological approach. It is argued throughout that both types of approach can be valid, both can be useful and both are suitable methodologies for remote sensing in geography.