The optimal accumulation of human capital over the life cycle / BEBR No.553

Includes bibliographical references (p. 28)."This paper summarizes the important contributions of the new life cycle human capital literature and demonstrates that many of these results can be derived more simply than in their original presentations. Within three period discrete-time framework it is demonstrated how the optimal pattern of human capital investment over the life cycle depends upon the choice of the objective function, the life cycle of leisure, and the extent of nonmarket benefits of human capital. The paper offers sufficient conditions for the optimality of a profile of monotonically declining investment activity over the life cycle.

The application of time-series MODIS NDVI profiles for the acquisition of crop information across Afghanistan

We investigated and developed a prototype crop information system integrating 250 m Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) data with other available remotely sensed imagery, field data, and knowledge as part of a wider project monitoring opium and cereal crops. NDVI profiles exhibited large geographical variations in timing, height, shape, and number of peaks, with characteristics determined by underlying crop mixes, growth cycles, and agricultural practices. MODIS pixels were typically bigger than the field sizes, but profiles were indicators of crop phenology as the growth stages of the main first-cycle crops (opium poppy and cereals) were in phase. Profiles were used to investigate crop rotations, areas of newly exploited agriculture, localized variation in land management, and environmental factors such as water availability and disease. Near-real-time tracking of the current years’ profile provided forecasts of crop growth stages, early warning of drought, and mapping of affected areas. Derived data products and bulletins provided timely crop information to the UK Government and other international stakeholders to assist the development of counter-narcotic policy, plan activity, and measure progress. Results show the potential for transferring these techniques to other agricultural systems

Electron Optics

Contains research objectives and summary of research on one research project.Joint Services Electronics Program (Contract DAAB07-75-C-1346

Survey and monitoring of opium poppy and wheat in Afghanistan: 2003-2009

An integrated application of remote-sensing technology was devised and applied in Afghanistan during 2003–2009 providing critical information on cereal and poppy cultivation and poppy eradication. The results influenced UK and international policy and counter-narcotics actions in Afghanistan

Farm Land Ownership as a Source of Retirement Income

Land Economics/Use,

Electron Optics

Contains reports on two research projects.Joint Services Electronics Program (Contract DAAB07-75-C-1346

A Presynaptic Kainate Receptor Is Involved in Regulating the Dynamic Properties of Thalamocortical Synapses during Development

AbstractPrevious studies have shown that pharmacological activation of presynaptic kainate receptors at glutamatergic synapses facilitates or depresses transmission in a dose-dependent manner. However, the only synaptically activated kainate autoreceptor described to date is facilitatory. Here, we describe a kainate autoreceptor that depresses synaptic transmission. This autoreceptor is present at developing thalamocortical synapses in the barrel cortex, specifically regulates transmission at frequencies corresponding to those observed in vivo during whisker activation, and is developmentally down regulated during the first postnatal week. This receptor may, therefore, limit the transfer of high-frequency activity to the developing cortex, the loss of which mechanism may be important for the maturation of sensory processing

Laser desorption/ionization coupled to FT-ICR mass spectrometry for studies of natural organic matter

Laser desorption/ionization (LDI) was investigated as an ionization method for Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) studies of natural organic matter (NOM). Using International Humic Substances Society standards, Suwannee River fulvic acid (SRFA) and Suwannee River natural organic matter (SRNOM), LDI was found to ionize a very similar set of compounds (>90% of molecular formulas identity) to the matrix assisted laser desorption/ionization (MALDI), while producing higher quality spectra. A comparison of electrospray ionization (ESI) and LDI spectra showed that different types of compounds are ionized by these methods with only 9.9% of molecular formulas common to both. The compounds ionized by LDI/MALDI belong to low oxygen classes (maximum number of species for O7–O9), while ESI compounds belong to higher oxygen classes (maximum number of species for O14–O16). Compounds ionized by LDI can be classified as aliphatic, aromatic, and condensed aromatics in approximately equal measure, while aliphatic compounds dominated the ESI spectra of SRFA. In order to maximize the coverage of molecular species, LDI, as a particularly convenient and readily deployable ionization method, should be used routinely in combination with other ionization methods, such as ESI, for FTICR MS studies of NOM