Large area black body source for ITER ECE in situ calibration

Development and testing of a hot calibration source for the ECE systems on ITER is underway. The source is intended to meet the requirements described in DDD55 Overview of Diagnostics. The requirement is for two 200 mm diameter sources. One will operate at atmospheric pressure and be well removed from the experiment. The other will operate in vacuum near the plasma. Both will operate at temperatures up to 800 °C. Here we report on the development of a prototype hot calibration source and of a realistic thermal model of the hot calibration source that will be used in simulations of the thermal properties of the source. Selection of a reliable heating method is challenging. Heating methods under consideration will be discussed.Center for Electromechanic

Electronic structure, phase stability and chemical bonding in Th2_2Al and Th2_2AlH4_4

We present the results of theoretical investigation on the electronic structure, bonding nature and ground state properties of Th$_2$Al and Th$_2$AlH$_4$ using generalized-gradient-corrected first-principles full-potential density-functional calculations. Th$_2$AlH$_4$ has been reported to violate the "2 \AA rule" of H-H separation in hydrides. From our total energy as well as force-minimization calculations, we found a shortest H-H separation of 1.95 {\AA} in accordance with recent high resolution powder neutron diffraction experiments. When the Th$_2$Al matrix is hydrogenated, the volume expansion is highly anisotropic, which is quite opposite to other hydrides having the same crystal structure. The bonding nature of these materials are analyzed from the density of states, crystal-orbital Hamiltonian population and valence-charge-density analyses. Our calculation predicts different nature of bonding for the H atoms along $a$ and $c$. The strongest bonding in Th$_2$AlH$_4$ is between Th and H along $c$ which form dumb-bell shaped H-Th-H subunits. Due to this strong covalent interaction there is very small amount of electrons present between H atoms along $c$ which makes repulsive interaction between the H atoms smaller and this is the precise reason why the 2 {\AA} rule is violated. The large difference in the interatomic distances between the interstitial region where one can accommodate H in the $ac$ and $ab$ planes along with the strong covalent interaction between Th and H are the main reasons for highly anisotropic volume expansion on hydrogenation of Th$_2$Al.Comment: 14 pages, 9 figure

Assessment of the Socio-Economic Impact of Late Blight and State of the Art of Management in European Organic Potato Production Systems

In Europe, late blight, caused by Phytophthora infestans, is the most devastating disease affecting organic (and conventional) potato production. Under suitable environmental conditions the disease can spread rapidly and it can cause complete crop loss. The extent of damage due to late blight depends on several factors: in organic production systems these factors include climate, choice of variety, soil management and use of crop protection agents such as copper. Therefore, the extent of economic damage varies between European regions. Council Regulation (EEC) No 2092/91, amended by Commission Regulation (EC) No 473/2002 of 15 March 2002 regulates the use of copper in organic agriculture. Copper has been the single most important control agent in organic late blight control. Therefore, the reduction or an eventual phasing out of copper use will have varying impacts in different regions. This report presents the results of a detailed survey that has been conducted in 7 European countries in the year 2001. It is a subproject of the EU-funded project Blight-MOP (QLRT 31065). The survey investigates legislative, socio-economic and production parameters. The aim of this study was: (i) to obtain an inventory of the current organic potato production techniques, (ii) to assess the impact of a potential ban of copper on yields and viability of organic potato production and (iii) to identify alternative plant protection strategies that are used by organic farmers. This report includes: (i) statistics on yields, farm gate prices, and production techniques, (ii) an analysis offarmer observations and experiences on the extent and impact of late blight epidemics, (iii) an analysis of the farmer’s motivations, expectations and their assessment of the potential impact of a copper ban. Using multiple linear regression we identified production factors which appear to consistently contribute to production success

The ^4He trimer as an Efimov system

We review the results obtained in the last four decades which demonstrate the Efimov nature of the $^4$He three-atomic system.Comment: Review article for a special issue of the Few-Body Systems journal devoted to Efimov physic

Electroexcitation of the Δ+(1232)\Delta^{+}(1232) at low momentum transfer

We report on new p$(e,e^\prime p)\pi^\circ$ measurements at the $\Delta^{+}(1232)$ resonance at the low momentum transfer region. The mesonic cloud dynamics is predicted to be dominant and rapidly changing in this kinematic region offering a test bed for chiral effective field theory calculations. The new data explore the low $Q^2$ dependence of the resonant quadrupole amplitudes while extending the measurements of the Coulomb quadrupole amplitude to the lowest momentum transfer ever reached. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations that include pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements suggest that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements

Tomato: a crop species amenable to improvement by cellular and molecular methods

Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures. In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.

Causes of morphological discontinuities in soils of Depressão Central, Rio Grande do Sul State, Brazil

Morphological, particularly textural, discontinuities between horizons increase soil erodibility in Depressão Central, Rio Grande do Sul State (Brazil). Characterization of such discontinuities would help to understand landscape evolution and to model near-surface hydrology. The objective of this research was to explore the relationship between morphological discontinuity and deposition of transported materials during pedogenesis. Transported material was meant to be mineral particles found in the soil profile, transported probably by water or gravity, that were not present neither in the parent material nor derived from it. Five soils of this region (two Alfisols, two Ultisols and one Mollisol) were sampled and morphological, sand grain size statistics, chemical and mineralogical analyses were used to search for evidences of deposition of transported materials. Two soils had abrupt textural change but no evidence of deposition of transported materials, two soils had less contrasting morphology and some characteristics that are possibly related to deposition, and one soil had no morphological discontinuity, but had deposition of material enriched in magnetite-maghemite in the sand fraction of the A horizon. Therefore, there were no relationship between morphological discontinuity and deposition of transported materials for these profiles in the Depressão Central.Contrastes morfológicos entre horizontes, e particularmente os contrastes texturais, aumentam a erodibilidade do solo na Depressão Central do Rio Grande do Sul (Brasil). A caracterização destes contrastes contribui para a compreensão da evolução da paisagem e para a modelagem da hidrologia de superfície. Cinco solos desta região foram amostrados e a morfologia, distribuição do tamanho de grãos da fração areia, análises químicas e mineralógicas foram usadas para tentativamente relacionar o contraste textural e morfológico com materiais transportados durante a pedogênese. Por materiais transportados entendem-se as partículas minerais presentes no perfil do solo, transportadas provavelmente por água ou gravidade, e que não estavam presentes nem no material de origem e nem foram derivadas deste. Dois solos apresentaram mudança textural abrupta sem evidências de deposição, dois solos apresentaram menor contraste morfológico e evidências que sustentam a possibilidade de deposição e um solo não apresentou contraste morfológico, porém as características indicam deposição de material rico em magnetita-maghemita na fração areia do horizonte A. Portanto, não foi encontrada relação entre descontinuidades morfológicas e deposição de materiais transportados, na Depressão Central

Maximum Likelihood and Gaussian Estimation of Continuous Time Models in Finance

Published in Handbook of financial time series, 2008, https://doi.org/10.1007/978-3-540-71297-8_22</p

Maximum likelihood and Gaussian estimation of continuous time models in finance

Ministry of Education, Singapore under its Academic Research Funding Tier