449 research outputs found
Men's lib? The effect of marriage on the social life of men in Ashaiman
Changing family studie
Breeding of resistant strawberry cultivars for organic fruit production – Diallel crossing strategies and resistance tests for Botrytis cinerea and Xanthomonas fragariae
Organic strawberry production suffers from high yield losses caused by numerous fungal and bacterial diseases. Two of the most important diseases are the grey mould disease caused by Botrytis cinerea Pers. (teleomorph Botryotinia fuckeliana), and the bacterial angular leaf spot disease caused by Xanthomonas fragariae (Kennedy & King). Beside cultivation methods and organic plant protection measures, the development of resistant cultivars seems to be the most promising strategy in order to improve the productivity in organic strawberry cultivation. Therefore, we established resistance tests to determine resistant and susceptible strawberry cultivars and breeding selections. In a first run, 40 different cultivars and selections were tested for their susceptibility towards B. cinerea by artificial inoculation of fruits and leaves and evaluation of the disease symptoms. Plants of 40 cultivars were tested for susceptibility to X. fragariae by artificial inoculation in the greenhouse. In a diallel crossing approach, 12 commonly cultivated strawberry cultivars have been crossed reciprocally and propagated in a field trial. Important characteristics of the progeny such as ripening time, yield, morphological traits and occurrence of diseases have been evaluated for a period of two consecutive years and lead to the determination of general (GCA) and specific (SCA) combining abilities. Together with the results of the resistance tests we identified a set of genotypes that show resistant characteristics towards B. cinerea and might be suitable for use in organic cultivation systems. Furthermore, they can be used for targeted breeding experiments in the future
Resistance Breeding in Apple at Dresden-Pillnitz
Resistance breeding in apple has a long tradition at the Institute of Fruit Breeding now Julius Kuehn-institute in Dresden-Pillnitz. The breeding was aimed at the production of multiple resistance cultivars to allow a more sustainable and environmentally friendly production of apple. In the last decades a series of resistant cultivars (Re®-cultivars) bred in Dresden-Pillnitz has been released, ‘Recolor’ and ‘Rekarda’ in 2006. The main topic in the resistance breeding programme was scab resistance and the donor of scab resistance in most cultivars was Malus x floribunda 821. Due to the development of strains that are able to overcome resistance genes inherited by M. x floribunda 821 and due to the fact that single resistance genes can be broken easily, pyramiding of resistance genes is necessary. Besides scab, fire blight and powdery mildew are the main disease for which a pyramiding of genes is aspired in Pillnitz. Biotechnical approaches are necessary for the early detection of pyramided resistance genes in breeding clones. This paper will give an overview of the resistance breeding of apple in Pillnitz and the methods used
Existence and approximation of Hunt processes associated with generalized Dirichlet forms
We show that any strictly quasi-regular generalized Dirichlet form that
satisfies the mild structural condition D3 is associated to a Hunt process, and
that the associated Hunt process can be approximated by a sequence of
multivariate Poisson processes. This also gives a new proof for the existence
of a Hunt process associated to a strictly quasi-regular generalized Dirichlet
form that satisfies SD3 and extends all previous results.Comment: Revised, shortened and improved versio
Optical spectroscopy and the nature of the insulating state of rare-earth nickelates
Using a combination of spectroscopic ellipsometry and DC transport
measurements, we determine the temperature dependence of the optical
conductivity of NdNiO and SmNiO films. The optical spectra show the
appearance of a characteristic two-peak structure in the near-infrared when the
material passes from the metal to the insulator phase. Dynamical mean-field
theory calculations confirm this two-peak structure, and allow to identify
these spectral changes and the associated changes in the electronic structure.
We demonstrate that the insulating phase in these compounds and the associated
characteristic two-peak structure are due to the combined effect of
bond-disproportionation and Mott physics associated with half of the
disproportionated sites. We also provide insights into the structure of excited
states above the gap.Comment: 12 pages, 13 figure
Approaching finite-temperature phase diagrams of strongly correlated materials: a case study for V2O3
Examining phase stabilities and phase equilibria in strongly correlated
materials asks for a next level in the many-body extensions to the
local-density approximation (LDA) beyond mainly spectroscopic assessments. Here
we put the charge-self-consistent LDA+dynamical mean-field theory (DMFT)
methodology based on projected local orbitals for the LDA+DMFT interface and a
tailored pseudopotential framework into action in order to address such
thermodynamics of realistic strongly correlated systems. Namely a case study
for the electronic phase diagram of the well-known prototype Mott-phenomena
system VO at higher temperatures is presented. We are able to describe
the first-order metal-to-insulator transitions with negative pressure and
temperature from the self-consistent computation of the correlated total energy
in line with experimental findings.Comment: 12 pages, 15 figures, new data adde
C–H Insertion via Ruthenium Catalyzed gem-Hydrogenation of 1,3-Enynes
gem-Hydrogenation of an internal alkyne with the aid of [Cp*RuCl]4 as the precatalyst is a highly unorthodox transformation, in which one C atom of the triple bond is transformed into a methylene group, whereas the second C atom gets converted into a ruthenium carbene. In the case of 1,3-enynes bearing a propargylic steering substituent as the substrates, the reaction occurs regioselectively, giving rise to vinyl carbene complexes that adopt interconverting η1/η3-binding modes in solution; a prototypical example of such a reactive intermediate was characterized in detail by spectroscopic means. Although both forms are similarly stable, only the η3-vinyl carbene proved kinetically competent to insert into primary, secondary, or tertiary C–H bonds on the steering group itself or another suitably placed ether, acetal, orthoester, or (sulfon)amide substituent. The ensuing net hydrogenative C–H insertion reaction is highly enabling in that it gives ready access to spirocyclic as well as bridged ring systems of immediate relevance as building blocks for medicinal chemistry. Moreover, the reaction scales well and lends itself to the formation of partly or fully deuterated isotopologues. Labeling experiments in combination with PHIP NMR spectroscopy (PHIP = parahydrogen induced polarization) confirmed that the reactions are indeed triggered by gem-hydrogenation, whereas kinetic data provided valuable insights into the very nature of the turnover-limiting transition state of the actual C–H insertion step
Zero-lag long-range synchronization via dynamical relaying
We show that simultaneous synchronization between two delay-coupled
oscillators can be achieved by relaying the dynamics via a third mediating
element, which surprisingly lags behind the synchronized outer elements. The
zero-lag synchronization thus obtained is robust over a considerable parameter
range. We substantiate our claims with experimental and numerical evidence of
these synchronization solutions in a chain of three coupled semiconductor
lasers with long inter-element coupling delays. The generality of the mechanism
is validated in a neuronal model with the same coupling architecture. Thus, our
results show that synchronized dynamical states can occur over long distances
through relaying, without restriction by the amount of delay.Comment: 10 pages, 4 figure
Resistenzzüchtung in Dresden-Pillnitz - Der Apfel
The Institute of Fruit Breeding has a long tradition in breeding resistant apple cultivars. Systematic resistance breeding started in the 1930 ties in Müncheberg. Material developed in Müncheberg was transferred in the 1970 ties to the Institute for Fruit Research, the antecessor of the Institute of Fruit Breeding. Based on this material, a couple of multiple resistant cultivars were generated. The time schedule for combining biotic and abiotic resistant traits which demonstrates the long-lasting period necessary for systematic resistance breeding is given. An overview of resistant cultivars of Dresden-Pillnitz and the respective resistant traits is presented. This assortment of cultivars was developed to provide a resistant cultivar for each ripening group and every application in fruit growing.
Modern resistance breeding is focused on quality and combination of different resistance genes for each pathogene to achieve durable resistance. Selection is facilitated by genetic markers. Likewise the look for new resistance genes, the analyses of genetics and the development of basic material are main areas of interest. Practical approaches in apple breeding to reach these aims are reported
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