826 research outputs found
Inferences from inventories of microbes in ecological vineyard settings
The effect of degraded soil conditions on microbial communities associating the rhizosphere and roots of grapevines was investigated within the frame of project CORE Organic Plus ReSolVe. Several relationships based on Dice cluster analyses of DGGE gel profiles suggest that fungal and bacterial communities from degraded and non-degraded areas differ. Results also suggest that composted organic amendments had an effect on community structures. However, the comparison of diversity indexes did not show differences between degraded and non-degraded plots. They suggested rich and even diversity of bacteria and fungi in any of the tested samples. Culture dependent analysis emphasized that a high diversity of Streptomyces spp. associates grapevine roots in degraded and non-degraded areas. Streptomyces species, best known for their potential to produce antibiotics, are increasingly depicted as beneficial plant associated bacteria
S-duality in SU(3) Yang-Mills Theory with Non-abelian Unbroken Gauge Group
It is observed that the magnetic charges of classical monopole solutions in
Yang-Mills-Higgs theory with non-abelian unbroken gauge group are in
one-to-one correspondence with coherent states of a dual or magnetic group
. In the spirit of the Goddard-Nuyts-Olive conjecture this
observation is interpreted as evidence for a hidden magnetic symmetry of
Yang-Mills theory. SU(3) Yang-Mills-Higgs theory with unbroken gauge group U(2)
is studied in detail. The action of the magnetic group on semi-classical states
is given explicitly. Investigations of dyonic excitations show that electric
and magnetic symmetry are never manifest at the same time: Non-abelian magnetic
charge obstructs the realisation of electric symmetry and vice-versa. On the
basis of this fact the charge sectors in the theory are classified and their
fusion rules are discussed. Non-abelian electric-magnetic duality is formulated
as a map between charge sectors. Coherent states obey particularly simple
fusion rules, and in the set of coherent states S-duality can be formulated as
an SL(2,Z)-mapping between sectors which leaves the fusion rules invariant.Comment: 27 pages, harvmac, amssym, one eps figure; minor misprints corrected
and title amende
Critical cooling rate and thermal stability of Zr–Ti–Cu–Ni–Be alloys
The critical cooling rate as well as the thermal stability are measured for a series of alloys in the Zr–Ti–Cu–Ni–Be system. Upon cooling from the molten state with different rates, alloys with compositions ranging along a tie line from (Zr70Ti30)55(Ni39Cu61)25Be20 to (Zr85Ti15)55(Ni57Cu43)22.5Be27.5 show a continuous increase in the critical cooling rate to suppress crystallization. In contrast, thermal analysis of the same alloys shows that the undercooled liquid region, the temperature difference between the glass transition temperature and the crystallization temperature, is largest for some compositions midway between the two endpoints, revealing that glass forming ability does not correlate with thermal stability. The relationship between the composition-dependent glass forming ability and thermal stability is discussed with reference to a chemical decomposition process
The interaction energy of well-separated Skyrme solitons
We prove that the asymptotic field of a Skyrme soliton of any degree has a
non-trivial multipole expansion. It follows that every Skyrme soliton has a
well-defined leading multipole moment. We derive an expression for the linear
interaction energy of well-separated Skyrme solitons in terms of their leading
multipole moments. This expression can always be made negative by suitable
rotations of one of the Skyrme solitons in space and iso-space.We show that the
linear interaction energy dominates for large separation if the orders of the
Skyrme solitons' multipole moments differ by at most two. In that case there
are therefore always attractive forces between the Skyrme solitons.Comment: 27 pages amslate
Prädiktoren der Recall-Compliance bei Parodontitispatienten
Die Zahnarzt-Patienten-Kommunikation im Erstgespräch bei Parodontitispatienten wird mit dem Roter Interaction Analysis System analysiert. Soziodemographische, psychologische und parodontologische Parameter werden analysiert, sowie Prädiktoren für Recall-Compliance erarbeitet. Die Kommunikation ist arztzentriert. Signifikant für Compliance sind beruhigende und psychosoziale Äußerungen des Zahnarztes. Offene Fragen der Patienten korrelieren mit Compliance, Berichte über die Therapie vom Patienten mit Non-Compliance. Leichter Knochenabbau, PA-chirurgische Eingriffe und Antibiose korrelieren genauso mit Compliance wie ein hohes Bildungsniveau, Privatversicherung und junges Alter der Probanden. Verminderte mundgesundheitsbezogene Lebensqualität spricht für Compliance, Depressivität für schlechte Compliance. Die Kommunikation im Erstgespräch kann richtungsweisend für die Mitarbeit der Patienten sein. Eine Fortbildung von Zahnärzten im Bereich der Gesprächsführung ist wünschenswert
transition form factors in Quenched and QCD
Calculations of the magnetic dipole, electric quadrupole and Coulomb
quadrupole amplitudes for the transition are presented
both in quenched QCD and with two flavours of degenerate dynamical quarks.Comment: Lattice2003(Matrix), 3 page
Boundary conditions and symplectic structure in the Chern-Simons formulation of (2+1)-dimensional gravity
We propose a description of open universes in the Chern-Simons formulation of
(2+1)-dimensional gravity where spatial infinity is implemented as a puncture.
At this puncture, additional variables are introduced which lie in the
cotangent bundle of the Poincar\'e group, and coupled minimally to the
Chern-Simons gauge field. We apply this description of spatial infinity to open
universes of general genus and with an arbitrary number of massive spinning
particles. Using results of [9] we give a finite dimensional description of the
phase space and determine its symplectic structure. In the special case of a
genus zero universe with spinless particles, we compare our result to the
symplectic structure computed by Matschull in the metric formulation of
(2+1)-dimensional gravity. We comment on the quantisation of the phase space
and derive a quantisation condition for the total mass and spin of an open
universe.Comment: 44 pages, 3 eps figure
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