4,617 research outputs found
Intracellular mycoparasites in action: interactions between powdery mildew fungi and Ampelomyces
Pycnidial fungi of the genus Ampelomyces are widespread intracellular
mycoparasites of powdery mildew fungi worldwide. Their pycnidia are produced
in hyphae, conidiophores and immature ascomata of their mycohosts.
Thus, they suppress both the asexual and the sexual reproduction of the
invaded powdery mildew mycelia, and then destroy them completely.
Conidia of Ampelomyces are released from the intracellular pycnidia by the
rupture of the pycnidial wall; conidia then germinate on the host plant
surfaces, penetrate the intact hyphae of powdery mildew mycelia found in
their vicinity and invade them internally growing from cell to cell through
the septal pores of the mycohost. The early stage of mycoparasitism is
apparently biotrophic, but the invaded cytoplasm then begins to die and a
necrotrophic interaction results. Toxin production has not been detected in
Ampelomyces, so it might act directly by invasion and destruction of the host cytoplasm. Experimental data showed that parasitized powdery mildew
colonies can continue their growth, but their sporulation is stopped soon
after Ampelomyces penetrated their mycelia. It is concluded that these
mycoparasites represent a stress factor in the life cycle of their mycohosts
but their role in the natural control of powdery mildew infections requires
further investigations
The Fourier transform of the non-trivial zeros of the zeta function
The non-trivial zeros of the Riemann zeta function and the prime numbers can
be plotted by a modified von Mangoldt function. The series of non-trivial zeta
zeros and prime numbers can be given explicitly by superposition of harmonic
waves. The Fourier transform of the modified von Mangoldt functions shows
interesting connections between the series. The Hilbert-Polya conjecture
predicts that the Riemann hypothesis is true, because the zeros of the zeta
function correspond to eigenvalues of a positive operator and this idea
encouraged to investigate the eigenvalues itself in a series. The Fourier
transform computations is verifying the Riemann hypothesis and give evidence
for additional conjecture that those zeros and prime numbers arranged in series
that lie in the critical 1/2 positive upper half plane and over the positive
integers, respectively.Comment: 4 page
Socio-Economic Impacts of the Agricultural Emissions Trading Scheme
Paper removed Feb. 14, 2013 at author's requestAgribusiness, Environmental Economics and Policy, Land Economics/Use,
The effect of climate change on the population of sycamore lace bug (Corythuca ciliata, Say) based on a simulation model with phenological response
Climate change affects on insect populations in many ways: it can cause a shift in geographical spread, abundance, or diversity, it can change the location, the timing and the magnitude of outbreaks of pests and it can define the phenological or even the genetic properties of the species. Long-time investigations of special insect populations, simulation models and scenario studies give us very
important information about the response of the insects far away and near to our century. Getting to know
the potential responses of insect populations to climate change makes us possible to evaluate the
adaptation of pest management alternatives as well as to formulate our future management policy. In this
paper we apply two simple models, in order to introduce a complex case study for a Sycamore lace bug
population. We test how the model works in case the whether conditions are very different from those in
our days. Thus, besides we can understand the processes that happen in present, we can analyze the
effects of a possible climate change, as well
Hybrid automata dicretising agents for formal modelling of robots
Some of the fundamental capabilities required by autonomous vehicles and systems for their intelligent decision making are: modelling of the environment and forming data abstractions for symbolic, logic based reasoning. The paper formulates a discrete agent framework that abstracts and controls a hybrid system that is a composition of hybrid automata modelled continuous individual processes. Theoretical foundations are laid down for a class of general model composition agents (MCAs) with an advanced subclass of rational physical agents (RPAs). We define MCAs as the most basic structures for the description of complex autonomous robotic systems. The RPA’s have logic based decision making that is obtained by an extension of the hybrid systems concepts using a set of abstractions. The theory presented helps the creation of robots with reliable performance and safe operation in their environment. The paper emphasizes the abstraction aspects of the overall hybrid system that emerges from parallel composition of sets of RPAs and MCAs
Extraction of kinetic freeze-out properties and effect of resonance decays
We present STAR results from identified particle spectra measured in
= 62.4 GeV Au-Au collisions. Particle production and system
dynamics are compared to results at = 200 GeV. We extract
kinetic and chemical freeze-out parameters using blast wave model
parameterization and statistical model. We discuss the effect of resonance
decays on the extracted kinetic freeze-out parameters.Comment: Proceedings of the 21st Winter Workshop on Nuclear Dynamics,
Breckenridge, Colorado, February 5-12, 200
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