A Vision for the CGIAR: Sustainable Agriculture for a Food Secure World

A statement by an external panel appointed by the CGIAR Oversight Committee, and chaired by Gordon Conway. The need for a new, crisp fifteen page statement pointing the way to the future was identified at MTM92. A draft was discussed at MTM94. The completed version was available at ICW94, and was presented to the Ministerial-Level Meeting at Lucerne in January 1995

Knots with unknotting number 1 and essential Conway spheres

For a knot K in S^3, let T(K) be the characteristic toric sub-orbifold of the orbifold (S^3,K) as defined by Bonahon and Siebenmann. If K has unknotting number one, we show that an unknotting arc for K can always be found which is disjoint from T(K), unless either K is an EM-knot (of Eudave-Munoz) or (S^3,K) contains an EM-tangle after cutting along T(K). As a consequence, we describe exactly which large algebraic knots (ie algebraic in the sense of Conway and containing an essential Conway sphere) have unknotting number one and give a practical procedure for deciding this (as well as determining an unknotting crossing). Among the knots up to 11 crossings in Conway's table which are obviously large algebraic by virtue of their description in the Conway notation, we determine which have unknotting number one. Combined with the work of Ozsvath-Szabo, this determines the knots with 10 or fewer crossings that have unknotting number one. We show that an alternating, large algebraic knot with unknotting number one can always be unknotted in an alternating diagram. As part of the above work, we determine the hyperbolic knots in a solid torus which admit a non-integral, toroidal Dehn surgery. Finally, we show that having unknotting number one is invariant under mutation.Comment: This is the version published by Algebraic & Geometric Topology on 19 November 200

Mental health of UK university business students: Relationship with shame, motivation and self-compassion

There is growing awareness of mental health problems among UK business students, which appears to be exacerbated by students’ attitudes of shame toward mental health. This study recruited 138 UK business students and examined the relationship between mental health and shame, and mental health and potential protective factors such as self-compassion and motivation. A significant correlation between each of the constructs was observed and self-compassion was identified as an explanatory variable for mental health. Shame moderated the relationship between self-compassion and mental health. Integrating self-compassion training into business study programs may help to improve the mental health of this student group.N/

Determination of quantum labels based on projections of the total angular momentum on the molecule-fixed axis

Molecular line lists, particularly those computed for high temperature applications, often have very few states assigned local quantum numbers, i.e rotational and vibrational quantum labels. These are often important components for accurately determining line shape parameters required for radiative transfer simulations. Through variational calculations, the projection of the total angular momentum onto the molecule fixed axis (k) is investigated in the Radau internal coordinate system to determine when it can be considered a good quantum number. In the Radau coordinate system, when the square of the th component of the wavefunction is greater than one half, then we can classify k as a good quantum number in accordance with the theorem of Hose and Taylor, a quantum analogue of the Kolmogorov–Arnold–Moser theorem. When the theorem is satisfied, it is shown that k can reliably be used to determine oblate and prolate quantum labels K and K . This approach is tested on the states of the water and ozone molecules

The concordance genus of knots

In knot concordance three genera arise naturally, g(K), g_4(K), and g_c(K): these are the classical genus, the 4-ball genus, and the concordance genus, defined to be the minimum genus among all knots concordant to K. Clearly 0 <= g_4(K) <= g_c(K) <= g(K). Casson and Nakanishi gave examples to show that g_4(K) need not equal g_c(K). We begin by reviewing and extending their results. For knots representing elements in A, the concordance group of algebraically slice knots, the relationships between these genera are less clear. Casson and Gordon's result that A is nontrivial implies that g_4(K) can be nonzero for knots in A. Gilmer proved that g_4(K) can be arbitrarily large for knots in A. We will prove that there are knots K in A with g_4(K) = 1 and g_c(K) arbitrarily large. Finally, we tabulate g_c for all prime knots with 10 crossings and, with two exceptions, all prime knots with fewer than 10 crossings. This requires the description of previously unnoticed concordances.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol4/agt-4-1.abs.htm

On the Photometric Accuracy of RHESSI Imaging and Spectrosocopy

We compare the photometric accuracy of spectra and images in flares observed with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI)}spacecraft. We test the accuracy of the photometry by comparing the photon fluxes obtained in different energy ranges from the spectral-fitting software SPEX with those fluxes contained in the images reconstructed with the Clean, MEM, MEM-Vis, Pixon, and Forward-fit algorithms. We quantify also the background fluxes, the fidelity of source geometries, and spatial spectra reconstructed with the five image reconstruction algorithms. We investigate the effects of grid selection, pixel size, field-of-view, and time intervals on the quality of image reconstruction. The detailed parameters and statistics are provided in an accompanying CD-ROM and web page. We find that Forward-fit, Pixon, and Clean have a robust convergence behavior and a photometric accuracy in the order of a few percents, while MEM does not converge optimally for large degrees of freedom (for large field-of-views and/or small pixel sizes), and MEM-Vis suffers in the case of time-variable sources. This comparative study documents the current status of the RHESSI spectral and imaging software, one year after launch.Comment: 2 Figures, full version on http://www.lmsal.com/~aschwand/eprints/2003_photo/index.htm

Une agriculture durable pour la sécurité alimentaire mondiale

Alors que l'on croyait que les grandes inquiétudes quant à la sécurité alimentaire mondiale appartenaient au passé, de nouvelles interrogations se font jour. Les pays en développement pourront-ils faire face à la croissance des besoins alimentaires qui accompagnera le fort accroissement de la population dans les 40 ans à venir ? L'agriculture actuellement pratiquée risque, en effet, de dégrader fortement les ressources naturelles et l'on est inquiet de constater des plafonnements de rendements dans les régions où la révolution verte a suscité beaucoup d'espoirs. Un groupe d'experts a analysé ces risques et conclu à la nécessité d'entreprendre une nouvelle révolution verte, trente ans après la première. Qualifiée de révolution doublement verte, elle devra reproduire les performances de la première et, en même temps, respecter les grandes lois de l'écologie et favoriser un développement économique et social plus équitable. Il s'agit là de l'un des grands objectifs internationaux pour la recherche agronomique futur

Use of the complete basis set limit for computing highly accurate ab initio dipole moments

Calculating dipole moments with high-order basis sets is generally only possible for the light molecules, such as water. A simple, yet highly effective strategy of obtaining high-order dipoles with small, computationally less expensive basis sets is described. Using the finite field method for computing dipoles, energies calculated with small basis sets can be extrapolated to produce dipoles that are comparable to those obtained in high order calculations. The method reduces computational resources by approximately 50% (allowing the calculation of reliable dipole moments for larger molecules) and simultaneously improves the agreement with experimentally measured infrared transition intensities. For atmospherically important molecules which are typically too large to consider the use of large basis sets, this procedure will provide the necessary means of improving calculated spectral intensities by several percent