8,204 research outputs found
Micronutrients in Grassland Production
Micronutrients, also known as trace minerals, which chiefly include boron (B), molybdenum (Mo), copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe), are required in extremely small quantities by crops and livestock. Their name, however, is not meant to imply their role is minor. Their lack, e.g., can cause serious crop production problems in forages and health disorders in livestock. This presentation includes the response of forage legumes and grasses to micronutrients, their deficiency and sufficiency levels in forages and their sufficiency levels in livestock. Forage legumes are more responsive to micronutrients, particularly B and Mo, than grasses. There are fewer documented cases of Cu, Fe, Mn and Zn deficiencies than of B and Mo deficiencies in forages. Soil acidity is one of the primary factors affecting the availability of micronutrients to forages. Low soil pH, e.g., is the principal cause of Mo deficiency in soybeans in Brazil and in a variety of crops in eastern Canada. More often soil properties and environmental factors are more important than actual soil levels, in affecting micronutrient availability. Micronutrient deficiencies have been emerging as a major problem in intensively cultivated soils in many countries and have become one of the serious constraints to crop productivity. Deficiency symptoms for most micronutrients appear on the young leaves at the top of the plant, because most of these nutrients are not readily translocated. However, Mo is an exception in that it is readily translocated, and its deficiency symptoms generally appear on the whole plant. Toxicity symptoms, on the other hand, for most micronutrients appear on the older leaves of the plant which is very striking, e.g., for B. Soil, foliar and seed applied methods of micronutrient application to control their deficiency are discussed in detail. Frequently the Cu, Fe, Mn, Zn and Se levels in forages which are sufficient for optimum crop yields are not adequate to meet the needs of livestock. Selenium is a trace mineral which is not required by plants and maximum forage yields can be obtained on soils with very low amounts of soil Se. However, if animals are fed forage with low Se, they could suffer from serious muscular disorders and other diseases. White muscle disease caused due to Se deficiency is the most common disorder and is found in calves and lambs. Sufficiency levels of micronutrients for crops have been discussed in relation to the animal requirement
Linking Dynamical and Thermal Models of Ultrarelativistic Nuclear Scattering
To analyse ultrarelativistic nuclear interactions, usually either dynamical
models like the string model are employed, or a thermal treatment based on
hadrons or quarks is applied. String models encounter problems due to high
string densities, thermal approaches are too simplistic considering only
average distributions, ignoring fluctuations. We propose a completely new
approach, providing a link between the two treatments, and avoiding their main
shortcomings: based on the string model, connected regions of high energy
density are identified for single events, such regions referred to as quark
matter droplets. Each individual droplet hadronizes instantaneously according
to the available n-body phase space. Due to the huge number of possible hadron
configurations, special Monte Carlo techniques have been developed to calculate
this disintegration.Comment: Complete paper enclosed as postscript file (uuencoded
Characterization of informational completeness for covariant phase space observables
In the nonrelativistic setting with finitely many canonical degrees of freedom, a shift-covariant phase space observable is uniquely characterized by a positive operator of trace one and, in turn, by the Fourier-Weyl transform of this operator. We study three properties of such observables, and characterize them in terms of the zero set of this transform. The first is informational completeness, for which it is necessary and sufficient that the zero set has dense complement. The second is a version of informational completeness for the Hilbert-Schmidt class, equivalent to the zero set being of measure zero, and the third, known as regularity, is equivalent to the zero set being empty. We give examples demonstrating that all three conditions are distinct. The three conditions are the special cases for p = 1, 2, ∞ of a more general notion of p-regularity defined as the norm density of the span of translates of the operator in the Schatten-p class. We show that the relation between zero sets and p-regularity can be mapped completely to the corresponding relation for functions in classical harmonic analysisIn the nonrelativistic setting with finitely many canonical degrees of freedom, a shift-covariant phase space observable is uniquely characterized by a positive operator of trace one and, in turn, by the Fourier-Weyl transform of this operator. We study three properties of such observables, and characterize them in terms of the zero set of this transform. The first is informational completeness, for which it is necessary and sufficient that the zero set has dense complement. The second is a version of informational completeness for the Hilbert-Schmidt class, equivalent to the zero set being of measure zero, and the third, known as regularity, is equivalent to the zero set being empty. We give examples demonstrating that all three conditions are distinct. The three conditions are the special cases for p = 1, 2, ∞ of a more general notion of p-regularity defined as the norm density of the span of translates of the operator in the Schatten-p class. We show that the relation between zero sets and p-regularity can be mapped completely to the corresponding relation for functions in classical harmonic analysi
The ALPS project: open source software for strongly correlated systems
We present the ALPS (Algorithms and Libraries for Physics Simulations)
project, an international open source software project to develop libraries and
application programs for the simulation of strongly correlated quantum lattice
models such as quantum magnets, lattice bosons, and strongly correlated fermion
systems. Development is centered on common XML and binary data formats, on
libraries to simplify and speed up code development, and on full-featured
simulation programs. The programs enable non-experts to start carrying out
numerical simulations by providing basic implementations of the important
algorithms for quantum lattice models: classical and quantum Monte Carlo (QMC)
using non-local updates, extended ensemble simulations, exact and full
diagonalization (ED), as well as the density matrix renormalization group
(DMRG). The software is available from our web server at
http://alps.comp-phys.org.Comment: For full software and introductory turorials see
http://alps.comp-phys.or
What is the meaning of the statistical hadronization model?
The statistical model of hadronization succeeds in reproducing particle
abundances and transverse momentum spectra in high energy collisions of
elementary particles as well as of heavy ions. Despite its apparent success,
the interpretation of these results is controversial and the validity of the
approach very often questioned. In this paper, we would like to summarize the
whole issue by first outlining a basic formulation of the model and then
comment on the main criticisms and different kinds of interpretations, with
special emphasis on the so-called "phase space dominance". While the ultimate
answer to the question why the statistical model works should certainly be
pursued, we stress that it is a priority to confirm or disprove the fundamental
scheme of the statistical model by performing some detailed tests on the rates
of exclusive channels at lower energy.Comment: 14 pages, to be published in the Proceedings of the International
workshop "Focus on multiplicity", Bari (Italy) June 17-19 200
Comparative CRISPR type III-based knockdown of essential genes in hyperthermophilic Sulfolobales and the evasion of lethal gene silencing
CRISPR type III systems, which are abundantly found in archaea, recognize and degrade RNA in their specific response to invading nucleic acids. Therefore, these systems can be harnessed for gene knockdown technologies even in hyperthermophilic archaea to study essential genes. We show here the broader usability of this posttranscriptional silencing technology by expanding the application to further essential genes and systematically analysing and comparing silencing thresholds and escape mutants. Synthetic guide RNAs expressed from miniCRISPR cassettes were used to silence genes involved in cell division (cdvA), transcription (rpo8), and RNA metabolism (smAP2) of the two crenarchaeal model organisms Saccharolobus solfataricus and Sulfolobus acidocaldarius. Results were systematically analysed together with those obtained from earlier experiments of cell wall biogenesis (slaB) and translation (aif5A). Comparison of over 100 individual transformants revealed gene-specific silencing maxima ranging between 40 and 75%, which induced specific knockdown phenotypes leading to growth retardation. Exceedance of this threshold by strong miniCRISPR constructs was not tolerated and led to specific mutation of the silencing miniCRISPR array and phenotypical reversion of cultures. In two thirds of sequenced reverted cultures, the targeting spacers were found to be precisely excised from the miniCRISPR array, indicating a still hypothetical, but highly active recombination system acting on the dynamics of CRISPR spacer arrays. Our results indicate that CRISPR type III - based silencing is a broadly applicable tool to study in vivo functions of essential genes in Sulfolobales which underlies a specific mechanism to avoid malignant silencing overdose
Prüfung von Gewebewachstum, Mast- und Schlachtleistung sowie Produktqualität unterschiedlicher genetischer Herkünfte und deren züchterische Eignung für die ökologische Schweinefleischerzeugung
Mit Hilfe eines zweigeteilten Versuchsaufbaus wurde die Eignung unterschiedlicher Genotypen für die ökologische Schweinefleischerzeugung untersucht. Im Modul 1 wurden zur Bestimmung des Gewebewachstums (mit Hilfe der Magnet Resonanz Tomographie) und der Fleischqualität insgesamt 90 Tiere der Genetiken Bundeshybridzuchtprogramm (BHZP), Schwäbisch-Hällisches Schwein (SH), Piétrain x SH (PixSH) and Duroc x Deutsche Landrasse (DuxDL) ökologisch gemästet. Die SH-Schweine zeigten von Mastbeginn an das stärkste Fettgewebewachstum und das geringste Muskelwachstum. Die DuxDL-Tiere besaßen die höchsten mittleren Tageszunahmen. PixSH- und BHZP-Tiere besaßen die höchsten Muskelfleischanteile. Die PixSH-Tiere hatten zwar den niedrigsten pH45-Wert und die höchsten Tropfsaftverluste im großen Rückenmuskel 24 Stunden nach der Schlachtung, trotzdem waren keine Qualitätsabweichungen zu beanstanden. Im Modul 2 wurden insgesamt 682 Tiere der Genetiken BHZP, SH, Angler Sattelschwein (AS), PixSH, PixAS, Pi x Deutsches Edelschwein (PixDE) und DuxDL ökologisch und konventionell gehalten und gefüttert. Tageszunahme, Futterverwertung, Muskelfleischanteil, Fettmaße und Fleischqualität aller Schweine wurden durch ein lineares Model mit den fixen Effekten Umwelt (ökologisch, konventionell), Genetik, Geschlecht sowie Interaktion von Genetik and Umwelt geprüft. Obwohl signifikante Interaktionen zwischen Genotyp und Umwelt für die meisten Merkmale (außer Fleischqualität) gefunden wurden, konnten aber keine Unterschiede in der Rangierung zwischen den Genetiken innerhalb der beiden Umwelten beobachtet werden. So schnitten die unter konventionellen Haltungs- und Fütterungsbedingungen leistungsstärksten modernen Genetiken auch unter Ökobedingungen am besten ab. Es wird geschlussfolgert, dass bei vergleichbaren Vermarktungszielen die ökologische Schweinefleischerzeugung keine speziellen Zuchtprogramme benötigt
All Teleportation and Dense Coding Schemes
We establish a one-to-one correspondence between (1) quantum teleportation
schemes, (2) dense coding schemes, (3) orthonormal bases of maximally entangled
vectors, (4) orthonormal bases of unitary operators with respect to the
Hilbert-Schmidt scalar product, and (5) depolarizing operations, whose Kraus
operators can be chosen to be unitary. The teleportation and dense coding
schemes are assumed to be ``tight'' in the sense that all Hilbert spaces
involved have the same finite dimension d, and the classical channel involved
distinguishes d^2 signals. A general construction procedure for orthonormal
bases of unitaries, involving Latin Squares and complex Hadamard Matrices is
also presented.Comment: 21 pages, LaTe
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