Midinfrared spectral investigations of carbonates: Analysis of remotely sensed data

Recent airborne thermal infrared observations of Mars from the Kuiper Airborne Observatory (KAO) have provided evidence for the presence of carbonates, sulfates, and hydrates. Using the optical properties of calcite and anhydrite, it was estimated that CO3's and SO4's constituted about 1 to 3 and 10 to 15 wt. percent, repectively of the materials composing the atmospheric dust. Using the derived value as an estimate of total CO3 abundance, and making an assumption that the CO3's were uniformly distributed within the Martian regolith, it was estimated that such a CO3 reservoir could contain roughly 2 to 5 bars of CO2. While the results indicate that several volatile-bearing materials are present on Mars, the observations from the KAO are inherently limited in their ability to determine the spatial distributions of these materials. However, previous spacecraft observations of Mars provide both the spectral coverage necessary to identify these materials, as well as the potential for investigating their spatial variability. This has prompted us to pursue a reinvestigation of the Mariner 6 and 7 infrared spectrometer and Mariner 9 infrared interferometer spectrometer observations. The former data have been recently made available in digital format and calibration of wavelengths and intensities are almost complete. Additionally, we are pursuing the derivation of optical constants of more appropriate carbonates and sulfates

An improved synthesis of (2E,4Z)-6-(benzyloxy)-4-bromohexa-2,4-dien-1-ol

An improved synthesis of (2E,4Z)-6-(benzyloxy)-4-bromohexa-2,4-dien-1-ol has been devised. This new route increases the throughput and yield of the diene product by circumventing a low yielding preparation of boronic acid intermediate as well as removing the need to use multi-gram quantities of highly toxic thallium salts. In the process of developing this new route, a higher yielding preparation of ( E)-3-hydroxyprop-1-enylboronic acid was also achieved. (c) 2007 Elsevier Ltd. All rights reserved

IMPLICATIONS OF THE TAX REFORM ACT OF 1976 FOR FARM ESTATE PLANNING

An intergeneration transfer simulation model is used to project estate transfer costs and the value of transfers to the heirs before and after the tax reform act of 1976. Lower Federal estate taxes result for estates that qualify for the special use valuation of farmland provision of the new law. Replacing the $60,000 estate exemption with the$47,000 estate tax credit and revising the tax rate schedule increases Federal estate taxes when the taxable estate is between $1.175 million and$9.353 million. The new carryover basis rules for estate assets acquired from decedents dying after 1979 also increase transfer costs.Agricultural Finance,

FARM GROWTH AND ESTATE TRANSFER IN AN UNCERTAIN ENVIRONMENT

Farm Management,

Thermal infrared observations of Mars (7.5-12.8 microns) during the 1990 opposition

Thirteen spectra of Mars, in the 7.5 to 12.8 micron wavelength were obtained on 7 Dec. 1990 from the Infrared Telescope Facility (IRTF). For these observations, a grating with an ultimate resolving power of 120 to 250 was used and wavelengths were calibrated for each grating setting by comparison with the absorption spectrum of polystyrene measured prior to each set of observations. By sampling the Nyquist limit at the shortest wavelengths, an effective resolving power of about 120 over the entire wavelength range was achieved. A total of four grating settings were required to cover the entire wavelength region. A typical observing sequence consisted of: (1) positioning the grating in one of the intervals; (2) calibrating the wavelength of positions; and (3) obtaining spectra for a number of spots on Mars. Several observations of the nearby stellar standard star, alpha Tauri, were also acquired throughout the night. Each Mars spectrum represents an average of 4 to 6 measurements of the individual Mars spots. As a result of this observing sequence, the viewing geometry for a given location or spot on Mars does not change, but the actual location of the spot on Mars's surface varies somewhat between the different grating settings. Other aspects of the study are presented

Miller's (2009) WACC model: An extension

Miller (2009a) presents an analysis of the weighted average cost of capital WACC model. The paper attracts debate which uses a variety of repayment schedules to support the arguments raised. We present an extension of Miller's (2009a) WACC model in a world where interest is tax deductible and debt principal is paid at maturity. We also present the corresponding model for the required rate of return on levered equity which is a vital input to the WACC model. Since these models are unwieldy, we explore an alternative definition of the WACC. These models provide insights into the debate on Miller's (2009a) paper

A note resolving the debate on “The weighted average cost of capital is not quite right”

Miller (2009a) derives a weighted average cost of capital for the special case where the cash flows to equity and the cashflows to debt are annuities. The paper attracts debate. We show that the weighted average cost of capital is redundant in a world where interest paid is not tax deductible. The required rate of return on unlevered equity will consistently and reliably estimate the net present value of any project no matter the idiocyncratic beliefs of the analyst as to the year-by-year leverage of the project, or of the firm. We recommend that the weighted average cost of capital method is discarded. Our recommendation also applies to a world where interest paid is tax deductible

Bistable Behavior of the Dark Current in Copper-Doped Semi-Insulating Gallium Arsenide

The dark current characteristics of gallium arsenide doped with silicon and compensated with diffused copper were found to have a pronounced region of current controlled negative differential conductivity (ndc) similar to the characteristics of a thyristor. The resistivity of the semi‐insulating semiconductor was measured to be 105 Ω cm for applied voltages up to 2.2 kV, which corresponds to an average electric field of 38 kV/cm. At higher voltages, a transition to a stable high current state was observed with a current rate of rise exceeding 1011 A/s. There is evidence of the formation of at least one current filament during this transition. A theoretical model based on drift diffusion and boundary conditions that allows double carrier injection at the contacts has been used to show that the observed negative differential resistance is due to the filling of deep copper acceptors. The model also shows that the ndc curves may be tailored by adjusting the copper concentration. Doping of GaAs with various concentrations of copper was shown to change the dark current characteristics in a way predicted by the model

Active Adaptive Management in Insect Pest and Weed Control: Intervention with a Plan for Learning

A major problem in insect pest and weed management is uncertainty. Managers are faced with three main types of uncertainty: uncertainty about biological and environmental processes, and observational uncertainty. Active adaptive management (AAM) is management with a deliberate plan for learning about the managed system, so that management can be improved in the face of uncertainty. We discuss the potential benefits of applying AAM to insect pest and weed control with reference to a number of examples. We first address the possible uses for AAM in biological control, with particular reference to agent selection and release. We also propose applying AAM methods to resistance management and to spatial strategies for pest control. We conclude with an overview of AAM, a discussion of some of the potential limitations to its use in pest management, and the possibilities for increased implementation of AAM in the future