847 research outputs found
Altered stimulus frequency and intensity dependence of the somatosensory evoked potential in rats after acute application of two mitochondrial toxins
Mitochondrial toxins are a special group of toxicants with nervous system ef TRACT -
fects. The resulting nervous system damage could be detected and followed-up by means of
functional biomarkers but these still have to be worked out. In this work, adult male Wistar
rats were anesthetized with urethane, the left hemisphere was exposed, and a silver recording
electrode was placed on the projection area of the whiskers. The whisker pad was stimulated
with electric square pulses and the cortical response was recorded. The intensity of the stimulus
was varied between 25% and 100% (just supramaximal), and its frequency, between 1 and 10
Hz. Control records were taken, then one of the agents (3-nitrporopionic acid, a mitochondrial
toxin of microfungal origin: 20 mg/kg b.w.; or manganese, a heavy metal: 50 mg/kg b.w. in
chloride form) was injected ip. and further records were taken. Both agents had an effect on
the latency, but on the amplitude, only Mn. Of the relationships between stimulation settings
and evoked potential parameters, frequency dependence of latency had the clearest alteration
on application of Mn or 3-NP. Such effects may have the potency to be developed to functional
biomarkers, applicable in practical toxicology or in animal research
New developments in the experimental data for charged particle production of medical radioisotopes
The goal of the present work is to give a review of developments achieved
experimentally in the field of nuclear data for medically important
radioisotopes in the last three years. The availability and precision of
production related nuclear data is continuously improved mainly experimentally.
This review emphasizes a couple of larger fields: the Mo/Tc generator problem
and the generator isotopes in general, heavy alpha-emitters and the rare-earth
elements. Other results in the field of medical radioisotope production are
also listed.Comment: in Journal of Radioanalytical and Nuclear Chemistry 201
OPTICAL BISTABILITY OF A PRISM-COUPLED NONLINEAR SLAB WAVE GUIDE
We describe the bistable behaviour of a prism-coupled nonlinear double-boundary slab
waveguide. We show that the bistable light reflection is possible in the system when the
mismatch from the condition of the optimal waveguide excitation is adequately chosen. A
system based on this configuration is proposed to achieve a high-contrast bistable switch
Activation cross-sections of proton induced reactions on Sm up to 65 MeV
Activation cross sections for proton induced reactions on Sm are presented
for the first time for
Sm(p,xn)Eu,
Sm(p,x)Sm,
Sm(p,x)Pm and
Sm(p,x)Nd up to 65 MeV. The cross sections were measured via
activation method by using a stacked-foil irradiation technique and high
resolution gamma ray spectroscopy. The results were compared with results of
the nuclear reaction codes ALICE, EMPIRE and TALYS (results taken from TENDL
libraries). Integral yields of the activation products were calculated from the
excitation functions.Comment: arXiv admin note: text overlap with arXiv:1411.716
CHANGES OF WEIGHT AND IN-KERNEL CONTENT VALUES OF MAIZE HYBRIDS (OCCITAN, COLOMBA, DK-471) AS A RESULT OF DAMAGING BY EUROPEAN CORN BORER (OSTRINIA NUBILALIS HBN)
The research was conducted in the year 2001 on two fields sown with three different maize hybrids and was based on randomly chosen sample plots. The first survey was carried out on the field sown with hybrids COLOMBA and OCCITAN (total area 120 ha), the second survey was performed on 50 ha of hybrid DK-471. The assessment was focused primarily on the difference between the cobs developed by healthy and damaged maize plants with regards to their weight and the content of protein, fat and starch in the maize kernel.
The hybrids unambiguously reacted to infestation by the European Corn Borer by cob weight reduction. The decrease of kernel fat content in the case of COLOMBA and that of the starch content in the case of OCCITAN displayed significant dependence on the degree of infestation by the European Corn Borer. The results of the survey verifiably showed that in both cases either metabolism, or incorporation of protein, fat and starch had experienced disorder.
A close link has been ascertained between the growth of larvae population and the kernel-cob rate of the examined hybrids. The distribution and number of larvae significantly affected the weight of maize cobs of hybrid DK-471 and the quantity of the basic nutrient components (raw protein, fat and starch) incorporated in the kernel
Parallel versus Sequential Update and the Evolution of Cooperation with the Assistance of Emotional Strategies
Our study contributes to the debate on the evolution of cooperation in the single-shot Prisoner's Dilemma (PD) played on networks. We construct a model in which individuals are connected with positive and negative ties. Some agents play sign-dependent strategies that use the sign of the relation as a shorthand for determining appropriate action toward the opponent. In the context of our model in which network topology, agent strategic types and relational signs coevolve, the presence of sign-dependent strategies catalyzes the evolution of cooperation. We highlight how the success of cooperation depends on a crucial aspect of implementation: whether we apply parallel or sequential strategy update. Parallel updating, with averaging of payoffs across interactions in the social neighborhood, supports cooperation in a much wider set of parameter values than sequential updating. Our results cast doubts about the realism and generalizability of models that claim to explain the evolution of cooperation but implicitly assume parallel updating
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