Capitalising the value of free schools : the impact of supply characteristics and uncertainty.

There has been a growing literature in both the US (for example Haurin and Brasington 1996, and Black 1999) and the UK (for example Gibbons & Machin, 2003) that estimates the way in which school quality is capitalised into house prices. Cheshire and Sheppard 1995 and 1999 estimated hedonic models in which the quality of the secondary school to which a household was assigned was a significant variable which provided evidence that secondary school quality was being capitalised into the price of houses. In contrast Gibbons and Machin concluded that primary schools were more significant. Each of these analyses is predicated on the assumption that the value of local schools should be reflected in the value of houses. We argue here that this is rather too simple. We should expect variation in the capitalised price of a given school quality at either primary or secondary level according to the elasticity of supply of ‘school quality’ in the local market, the certainty with which that quality can be expected to be maintained over time and the suitability of the dwelling to accommodate children. These factors will vary systematically between and perhaps within cities. This paper explores the sources and the impact of such variations as well as the impact of model specification. The results provide new evidence on the complex and subtle ways in which housing markets capitalise the value of local public goods such as school quality and perhaps most importantly suggest that this is highly non-linear: houses in the catchment areas of only the best state schools command substantial premiums but such capitalised values can be very substantial indeed.

Intramolecular integration within Moloney murine leukemia virus DNA

By screening a library of unintegrated, circular Moloney murine leukemia virus (M-MuLV) DNA cloned in lambda phage, we found that approximately 20% of the M-MuLV DNA inserts contained internal sequence deletions or inversions. Restriction enzyme mapping demonstrated tht the deleted segments frequently abutted a long terminal repeat (LTR) sequence, whereas the inverted segments were usually flanked by LTR sequences, suggesting that many of the variants arose as a consequence of M-MuLV DNA molecules integrating within their own DNA. Nucleotide sequencing also suggested that most of the variant inserts were generated by autointegration. One of the recombinant M-MuLV DNA inserts contained a large inverted repeat of a unique M-MuLV sequence abutting an LTR. This molecule was shown by nucleotide sequencing to have arisen by an M-MuLV DNA Molecule integrating within a second M-MuLV DNA molecule before cloning. The autointegrated M-MuLV DNA had generally lost two base pairs from the LTR sequence at each junction with target site DNA, whereas a four-base-pair direct repeat of target site DNA flanked the integrated viral DNA. Nucleotide sequencing of preintegration target site DNA showed that this four-base-pair direct repeat was present only once before integration and was thus reiterated by the integration event. The results obtained from the autointegrated clones were supported by nucleotide sequencing of the host-virus junction of two cloned M-MuLV integrated proviruses obtained from infected rat cells. Detailed analysis of the different unique target site sequences revealed no obvious common features

Accurate ab initio calculations which demonstrate a 3 Pi u ground state for Al2

The spectroscopic parameters and separations between the three low-lying X 3 Pi u, A 3 Sigma g -, and a 1 Sigma g + states of Al2 are studied as a function of both the one-particle and n-particle basis set. Approximate correlation treatments are calibrated against full Cl calculations correlating the six valence electrons in a double-zeta plus two d-function basis set. Since the CASSCF/MRCI 3 Pi u to 3 Sigma g - separation is in excellent agreement wtih the FCI value, the MRCI calculations were carried out in an extended (20s13p6d4f)/(6s5p3d2f) gaussian basis. Including a small correction for relativistic effects, the best estimate is that 3 Sigma g - state lies 174/cm above the 3 Pi u ground state. The 1 Sigma g + state lies at least 2000/cm higher in energy. At the CPF level, inclusion of 2s and 2p correlation has little effect on D sub e, reduces T sub e by only 26/cm, and shortens the bond lengths by about 0.02 a sub o. Further strong support for a 3 Pi u ground state comes from the experimental absorption spectra, since both observed transitions can be convincingly assigned as 3 Pi u yields 3 Pi g. The (2) 3 Pi g state is observed to be sensitive to the level of correlation treatment, and to have its minimum shifted to shorter rho values, such that the strongest experimental absorption peak probably corresponds to the 0 yields 2 transition

Theoretical studies of the potential surface for the F - H2 greater than HF + H reaction

The F + H2 yields HF + H potential energy hypersurface was studied in the saddle point and entrance channel regions. Using a large (5s 5p 3d 2f 1g/4s 3p 2d) atomic natural orbital basis set, a classical barrier height of 1.86 kcal/mole was obtained at the CASSCF/multireference CI level (MRCI) after correcting for basis set superposition error and including a Davidson correction (+Q) for higher excitations. Based upon an analysis of the computed results, the true classical barrier is estimated to be about 1.4 kcal/mole. The location of the bottleneck on the lowest vibrationally adiabatic potential curve was also computed and the translational energy threshold determined from a one-dimensional tunneling calculation. Using the difference between the calculated and experimental threshold to adjust the classical barrier height on the computed surface yields a classical barrier in the range of 1.0 to 1.5 kcal/mole. Combining the results of the direct estimates of the classical barrier height with the empirical values obtained from the approximation calculations of the dynamical threshold, it is predicted that the true classical barrier height is 1.4 + or - 0.4 kcal/mole. Arguments are presented in favor of including the relatively large +Q correction obtained when nine electrons are correlated at the CASSCF/MRCI level

Remediation of RDX- and HMX-Contaminated Groundwater Using Organic Mulch Permeable Reactive Barriers

Organic mulch is a complex organic material that is typically populated with its own consortium of microorganisms. The organisms in mulch breakdown complex organics to soluble carbon, which can then be used by these and other microorganisms as an electron donor for treating RDX and HMX via reductive pathways. A bench-scale treatability study with organic mulch was conducted for the treatment of RDX- and HMX-contaminated groundwater obtained from a plume at the Pueblo Chemical Depot (PCD) in Pueblo, Colorado. The site-specific cleanup criteria of 0.55 ppb RDX and 602 ppb HMX were used as the logical goals of the study. Column flow-through tests were run to steady-state at the average site seepage velocity, using a 70%:30% (vol.:vol.) mulch:pea gravel packing to approach the formation\u27s permeability. Significant results included: (1) Complete removal of 90 ppb influent RDX and 8 ppb influent HMX in steady-state mulch column effluent; (2) pseudo-first-order steady-state kinetic rate constant, k, of 0.20 to 0.27 h-1 based on RDX data, using triplicate parallel column runs; (3) accumulation of reduced RDX intermediates in the steady-state column effluent at less than 2% of the influent RDX mass; (4) no binding of RDX to the column fill material; and (5) no leaching of RDX, HMX or reduction intermediates from the column fill material. The results of the bench-scale study will be used to design and implement a pilot-scale organic mulch/pea gravel permeable reactive barrier (PRB) at the site

Construction project change: Investigating cost and benefits

Cost overrun of projects is common in the construction industry. Changes to the original design and to the scope of works during the design development and construction phases contribute significantly to overall cost overrun of construction projects. However, scholars argue that change is inevitable, and some changes add value to the project. Therefore, it can be argued that the overrun of the initial construction cost through the changes made to the project may be insignificant compared to the reductions in life-cycle cost and whole life value of resultant built environments. Early research is presented here of a wider project seeking to evaluate the costs and value of proactive changes made during the construction phase with the intention to add value to the whole life of the project. Change control accounts and other related documentary evidence of two construction projects were investigated to identify changes made to the projects during the construction phase, and cost of those changes. Semi-structured interviews with quantity surveyors and project managers involved in those projects were conducted to enrich this documentary data. Analysis explored the contribution of proactive changes made with the intention to increase whole-life value to the overall cost overrun of construction projects, and clients’ understanding and willingness to pay for such changes. The next phase of this research will investigate the whole life value gained by the clients from these changes. Ultimately, this research aims to increase both clients and project managers understanding of cost and value of changes during the construction phase, with due consideration of the whole life cycle of construction projects

Spatial distribution of land type in regression models of pollutant loading

This paper proposes a method to improve landscape-pollution interaction regression models through the inclusion of a variable that describes the spatial distribution of a land type with respect to the pattern of runoff within a drainage catchment. The proposed index is used as an independent variable to enhance the strength, as quantified by R² values, of regression relationships between empirical observations of in-stream pollutant concentrations and land type by considering the spatial distribution of key land-type categories within the sample point’s drainage area. We present an index that adds a new dimension of explanatory power when used in conjunction with a variable describing the proportion of the land type. We demonstrate the usefulness of this index by exploring the relationship between nitrate ( - 3 NO ) and land type within 40 drainage sub-catchments in the Ipswich River watershed, Massachusetts. Nutrient loads associated with non-point source pollution paths are related to land type within the up-stream drainage catchments of sample sites. Past studies have focused on the quantity of particular land type within a sample point’s drainage catchment. Quantifying the spatial distribution of key land-type categories in terms of location on a runoff surface can improve our understanding of the relationship between sampled - 3 NO concentrations and land type. Regressions that employ the proportion of residential and agricultural land type within catchments provide a fair fit (R² = 0.67). However, we find that a regression adding a variable that indicates the spatial distribution of residential land improves the overall relationship between instream - 3 NO measurements and associated land types (R² = 0.712). We test the sensitivity of the results with respect to variations in the surface definition in order to determine the conditions under which the spatial index variable is useful

Bioelectric-calcineurin signaling module regulates allometric growth and size of the zebrafish fin

AbstractThe establishment of relative size of organs and structures is paramount for attaining final form and function of an organism. Importantly, variation in the proportions of structures frequently underlies adaptive change in morphology in evolution and maybe a common mechanism underlying selection. However, the mechanism by which growth is integrated within tissues during development to achieve proper proportionality is poorly understood. We have shown that signaling by potassium channels mediates coordinated size regulation in zebrafish fins. Recently, calcineurin inhibitors were shown to elicit changes in zebrafish fin allometry as well. Here, we identify the potassium channelkcnk5bas a key player in integrating calcineurin’s growth effects, in part through regulation of the cytoplasmic C-terminus of the channel. We propose that the interaction between Kcnk5b and calcineurin acts as a signaling node to regulate allometric growth. Importantly, we find that this regulation is epistatic to inherent mechanisms instructing overall size as inhibition of calcineurin is able to bypass genetic instruction of size as seen insofand wild-type fins, however, it is not sufficient to re-specify positional memory of size of the fin. These findings integrate classic signaling mediators such as calcineurin with ion channel function in the regulation of size and proportion during growth.</jats:p

Drivers of Natural Variation in Water-Use Efficiency Under Fluctuating Light Are Promising Targets for Improvement in Sorghum.

Improving leaf intrinsic water-use efficiency (iWUE), the ratio of photosynthetic CO2 assimilation to stomatal conductance, could decrease crop freshwater consumption. iWUE has primarily been studied under steady-state light, but light in crop stands rapidly fluctuates. Leaf responses to these fluctuations substantially affect overall plant performance. Notably, photosynthesis responds faster than stomata to decreases in light intensity: this desynchronization results in substantial loss of iWUE. Traits that could improve iWUE under fluctuating light, such as faster stomatal movement to better synchronize stomata with photosynthesis, show significant natural diversity in C3 species. However, C4 crops have been less closely investigated. Additionally, while modification of photosynthetic or stomatal traits independent of one another will theoretically have a proportionate effect on iWUE, in reality these traits are inter-dependent. It is unclear how interactions between photosynthesis and stomata affect natural diversity in iWUE, and whether some traits are more tractable drivers to improve iWUE. Here, measurements of photosynthesis, stomatal conductance and iWUE under steady-state and fluctuating light, along with stomatal patterning, were obtained in 18 field-grown accessions of the C4 crop sorghum. These traits showed significant natural diversity but were highly correlated, with important implications for improvement of iWUE. Some features, such as gradual responses of photosynthesis to decreases in light, appeared promising for improvement of iWUE. Other traits showed tradeoffs that negated benefits to iWUE, e.g., accessions with faster stomatal responses to decreases in light, expected to benefit iWUE, also displayed more abrupt losses in photosynthesis, resulting in overall lower iWUE. Genetic engineering might be needed to break these natural tradeoffs and achieve optimal trait combinations, e.g., leaves with fewer, smaller stomata, more sensitive to changes in photosynthesis. Traits describing iWUE at steady-state, and the change in iWUE following decreases in light, were important contributors to overall iWUE under fluctuating light