Production of carboxylates (C-A) by young sugar-beet plants grown in nutrient solution.

In growth-chamber experiments, sugar beet seedlings were grown in nutrient solution. Plants were harvested 30, 36, 39, 43, 46 or 51 days after germination, leaf blades (including midribs), petioles and storage roots plus fibrous roots were analysed for Na, K, Ca, Mg, H2PO4, NO3, Cl, SOt, total N and 5 organic acids, and fresh and dry weights were recorded. The total content of carboxylates (C-A) was calculated by subtracting the sum of inorganic anions from the sum of inorganic cations. Amounts of C-A and organic N were about equal; there was no release of carboxylates resulting from NO3- and SO4- reduction in the leaves of sugar beet. Only a small amount of carboxylates reached the root system and no excess uptake of inorganic anions over inorganic cations accompanied by a decarboxylation of carboxylates occurred. In sugar beet plants the C-A content was not constant during the growth period studied. The NO3- reduction per g leaf/day decreased rapidly with time and was accompanied by a decrease in oxalate production. The high oxalate content in the leaves was thought to account for the decrease in NO3- reduction. GMC. (Abstract retrieved from CAB Abstracts by CABI’s permission

Nitrate reductase activity and oxalate content of sugar-beet leaves.

Diploid sugar beet was grown in controlled environment at 25/17 deg C in 14-h photoperiods in well aerated, regularly changed nutrient solution containing 6 meq NO3/l. When 6 leaves had been expanded, the total carboxylate content of the oldest leaf (leaf 1) was found to be 5836 meq/kg DM, while that of leaf 6 was only 2312 meq/kg; the difference was mainly due to oxalate content, which was 5236 meq/kg in leaf 1 and 1744 meq/kg in leaf 6. Nitrate-N content was about 50% higher in leaf 1 than in leaf 4. Nitrate-reductase activity fell to very low values as leaves aged. Experiments in which young and old leaf material was mixed, or oxalate at 0-4000 meq/kg DM was added to leaf samples, showed that oxalate had no substantial effect on nitrate-reductase activity. (Abstract retrieved from CAB Abstracts by CABI’s permission

Collective polarization exchanges in collisions of photon clouds

The one-loop "vacuum" Heisenberg-Euler coupling of four electromagnetic fields can lead to interesting collective effects in the collision of two photon clouds, on a time scale orders of magnitude faster than one estimates from the cross-section and density. We estimate the characteristic time for macroscopic transformation of positive to negative helicity in clouds that are initially totally polarized and for depolarization of a polarized beam traversing an unpolarized cloud.Comment: Recapitulates much that is in hep-ph/0402127, with new results in the last section, and the first section drastically reduced in view of the previous work of Kotkin and Serbo. Typo corrected in eq. 1

Changes in production of organic nitrogen and carboxylates (C-A) in young sugar-beet plants grown in nutrient solutions of different nitrogen composition.

Sugar-beet seedlings grown in controlled environment for 19 days in culture solution containing nitrate were then grown with nitrate, ammonium or no N. Carboxylate levels (in meq.) were approximately equal to organic N levels (in mM) in plants given nitrate, were lower in plants grown with ammonium and were higher in plants grown without further N; this was accompanied by a slight rise in culture solution pH where nitrate was supplied and a sharp drop in pH in the other treatments.-R.B. (Abstract retrieved from CAB Abstracts by CABI’s permission

The ionic balance of the sugar-beet plant

The ionic balance of the sugar-beet plant was studied by measuring dry weight and chemical composition of every leaf, the crown and the root during the growing season.The sugar-beet plant has an almost neutral uptake. The nitrate and sulphate reduction determines the amount of carboxylates in the plant. Accumulation of carboxylates prevents large changes of cell-pH because of the ion-uptake and ion-utilization processes.In every plant part the carboxylates are a quantitative measure of the amount of nitrate reduced. It is concluded that nitrate is mainly reduced in the leaves and to a small extent in the root.It is proved that for the sugar-beet plant, Cl can be used as an index element to calculate the supply of the various ions to the various plant parts. Redistribution of potassium, calcium, magnesium, phosphate and organic N is determined by comparing the actual and calculated amounts in the various plant parts. The redistribution of potassium from the old leaves to the root is counterbalanced by redistribution of divalents in the opposite direction. The redistribution of the divalents takes place from organs with a relatively small oxalate production towards organs with a relatively large oxalate production.In an appendix a rapid carboxylate determination is described

Advancing interoperable soil data exchange for global soil data information systems

In order to be able to address local, regional and global issues such as sustainable land management, food security, climate change mitigation and soil-related indicators of the UN Agenda for Sustainable Development the need for reliable, relevant and accurate soil information and data is increasing. Currently, ..

A selection of sensing techniques for mapping soil hydraulic properties

Data on soil hydraulic properties are needed as input for many models, such as models to predict unsaturated water movement and crop growth, and models to predict leaching of nutrients and pesticides to groundwater. The soil physics database of the Netherlands shows several lacunae, and a substantial part of the data were collected more than thirty years ago and thus might not represent actual soil hydraulic conditions

Some remarks on the spectral functions of the Abelian Higgs Model

We consider the unitary Abelian Higgs model and investigate its spectral functions at one-loop order. This analysis allows to disentangle what is physical and what is not at the level of the elementary particle propagators, in conjunction with the Nielsen identities. We highlight the role of the tadpole graphs and the gauge choices to get sensible results. We also introduce an Abelian Curci-Ferrari action coupled to a scalar field to model a massive photon which, like the non-Abelian Curci-Ferarri model, is left invariant by a modified non-nilpotent BRST symmetry. We clearly illustrate its non-unitary nature directly from the spectral function viewpoint. This provides a functional analogue of the Ojima observation in the canonical formalism: there are ghost states with nonzero norm in the BRST-invariant states of the Curci-Ferrari model.Comment: 32 pages, 12 figure

Информационное обеспечение в процессно-ориентированной модели управления предприятиями

Приведено описание информационного обеспечения как составной части менеджмента производственного предприятия в его современном, процессном представлении. Информационное обеспечение предприятий связано с качеством функционирования, которое с точки зрения процессно-ориентированных стандартов характеризуется результативностью и эффективностью.It has been accomplished the description of data-ware as a component of manufacturing enterprise management in its modern process presentation. The data-ware of enterprise is connected with quality of functioning, which is defined by effectiveness and efficiency of the according process-oriented standards