THE CURRENT AND FUTURE WORLD FOOD SITUATION: IS THERE AN EMERGING FOOD SHORTAGE?

This paper gives an overview of the current and projected food situation in the U.S. and the world.Food Security and Poverty,

Applications of Iridium-Catalyzed Isomerization Claisen Rearrangements (ICR) to Complex Molecule Synthesis

The iridium-catalyzed isomerization Claisen rearrangement (ICR) methodology developed in theNelson group has provided access to a broad range of diastereomerically enricheddisubstituted unsaturated aldehydes. Allylsilyl aldehydes produced by the ICR reaction havebeen further elaborated into substrates for highly diastereoselective intramolecular Hosomi-Sakurai annulation reactions. The Sakurai annulation has proven to be particularly powerfulwhen carried out in tandem with intramolecular aldol or Mannich reactions to form complexfused ring systems. An attempted strategic application of this methodology to the synthesis ofthe Rauwolfia alkaloids reserpine and yohimbine is detailed.Vinyl boronic esters have been demonstrated to be effective precursors for the ICRreaction providing diastereomerically enriched boronic aldehydes. The potential forintramolecular chelation between the newly formed aldehyde and proximal boronic ester hasbeen investigated. The boron functionality has proven to be useful for accessing alkoxy- andaryl-substituted compounds that are typically unavailable from the ICR reaction. A synthesis ofthe plant growth inhibitor penieone has been explored in order to demonstrate the practicalapplication of this methodology to complex molecule construction

Biodegradation and Characterization of a Bio-based Polyester

Anaerobic biodegradation in sewage sludge and aerobic biodegradation in compost of polyhydroxybutyrate (PHB) were investigated to determine degradation kinetics and identify changes in polymer properties. To determine the impact of a natural plasticizer on biodegradation, tributyl citrate (TBC) was blended with some test specimens. For comparison to another bioplastic, polylactic acid (PLA) was biodegraded in the anaerobic study. Evolved gaseous carbon was measured to assess biodegradability according to ASTM standards D5210 and D5338. Mass loss experiments were performed to facilitate determination of degradation kinetics. Melt-pressed plates of the bioplastic with five different initial mass-to-surface-area ratios (plate thicknesses of 0.24, 0.5, 1.2, 3.5 and 5.0 mm) were biodegraded to investigate the relationship between this parameter and decay rate coefficients for first order decay kinetics. Results showed that degradation rate coefficients were influenced by initial mass-to-surface-area ratio of the bioplastic seemingly according to saturation kinetics. In the first anaerobic mass loss experiment, degradation rate coefficients with respect to initial surface area of the 0.5-mm, 1.2-mm, and 3.5-mm PHB plates were 0.58, 1.29, and 2.07 mg cm-2 d-1, respectively. In the second anaerobic mass loss experiment, coefficients for the 0.24-mm, 1.2-mm, and 5-mm PHB plates were 0.32, 0.73, and 0.95 mg cm-2 d-1, respectively. Coefficients for the 1.2-mm PHB/15% TBC blend and PLA were 0.38 and 0.00 mg cm-2 d-1, respectively. In the first aerobic mass loss experiment, coefficients for the 0.5-mm, 1.2-mm, and 3.5-mm PHB plates were 0.33, 0.62, and 1.57 mg cm-2 d-1, respectively. In the second aerobic mass loss experiment, coefficients for the 0.24-mm, 1.2-mm, and 5-mm PHB plates were 0.16, 1.05, and 1.11 mg cm-2 d-1, respectively, and 0.04 mg cm-2 d-1 for the PHB/15% TBC blend. In both degrading environments, the TBC additive hindered the degradation rate of the PHB. Thermal properties, molecular bonding, and molecular weight as measured by DSC, FT-IR, and Size Exclusion Chromatography, respectively, seemed only slightly affected by biodegradation. Decreasing Izod pendulum impact strength of the PHB was the obvious result of polymer loss. Furthermore, scanning electron micrographs of degraded specimens were recorded for visual illustration of the degradation process

Epitaxial designs for maximizing efficiency in resonant tunnelling diode based terahertz emitters

We discuss the modelling of high current density InGaAs/AlAs/InP resonant tunneling diodes to maximize their efficiency as THz emitters. A figure of merit which contributes to the wall plug efficiency, the intrinsic resonator efficiency, is used for the development of epitaxial designs. With the contribution of key parameters identified, we analyze the limitations of accumulated stress to assess the manufacturability of such designs. Optimal epitaxial designs are revealed, utilizing thin barriers, with a wide and shallow quantum well that satisfies the strained layer epitaxy constraint. We then assess the advantages to epitaxial perfection and electrical characteristics provided by devices with a narrow InAs sub-well inside a lattice-matched InGaAs alloy. These new structures will assist in the realization of the next-generation submillimeter emitters

Characterisation of High Current Density Resonant Tunneling Diodes for THz Emission Using Photoluminescence Spectroscopy

We discuss the numerical simulation of high current density InGaAs/AlAs/InP resonant tunneling diodes with a view to their optimization for application as THz emitters. We introduce a figure of merit based upon the ratio of maximum extractable THz power and the electrical power developed in the chip. The aim being to develop high efficiency emitters as output power is presently limited by catastrophic failure. A description of the interplay of key parameters follows, with constraints on strained layer epitaxy introduced. We propose an optimized structure utilizing thin barriers paired with a comparatively wide quantum well that satisfies strained layer epitaxy constraints

Personal, social, health and economic (PSHE) education: A mapping study of the prevalent models of delivery and their effectiveness

In October 2008, then Schools Minister Ji, Knight announced that Personal, Social, Health and Economic (PSHE) education would become compulsory (for Key Stages 1-4). Following this, In November 2009, Sheffield Hallam University was contracted by DCSF (now DfE) to conduct a mapping exercise of PSHE education in primary and secondary schools in England. This resulted from a recommendation in the Macdonald Review, whcih identified the need for research to establish and report on the prevalent models of delivery for PSHE education and their effectiveness in improving outcomes for children and young people (Macdonald, 2009:8)

Early state papers of New Hampshire, including the Constitution of 1784, journals of the Senate and House of Representatives, and records of the President and council from June, 1790 to June, 1793 with an appendix. Volume XXII

Provincial and state papers, Volume 22; Vols. [2-3] have imprint: Concord, I. C. Evans, public printer, 1892-93

The impact of overturning and horizontal circulation in Pine Island Trough on ice shelf melt in the eastern Amundsen Sea

The ice shelves around the Amundsen Sea are rapidly melting as a result of the circulation of relatively warm ocean water into their cavities. However, little is known about the processes that determine the variability of this circulation. Here we use an ocean circulation model to diagnose the relative importance of horizontal and vertical (overturning) circulation within Pine Island Trough, leading to Pine Island and Thwaites ice shelves. We show that melt rates and southwardCircumpolar Deep Water (CDW)transports covary over large parts of the continental shelf at interannual to decadal time scales. The dominant external forcing mechanism for this variability is Ekman pumping and suction on the continental shelf and at the shelf break, in agreementwith previous studies.At the continental shelf break, the southward transport of CDWand heat is predominantly barotropic. Farther south within Pine Island Trough, northward and southward barotropic heat transports largely cancel, and the majority of the net southward temperature transport is facilitated by baroclinic and overturning circulations. The overturning circulation is related to water mass transformation and buoyancy gain on the shelf that is primarily facilitated by freshwater input from basal melting