973 research outputs found
Connection of frost tolerance and alkaloid accumulation potential in poppy (Papaver somniferum L.)
In the Central-European region, a growing interest for winter poppy varieties both for industrial and culinary purposes can be observed. In connection with breeding, we studied if winter hardiness and alkaloid accumulation capacity are linked in some way. Experimental plots sown in autumn and thinned (selected) due to winter frosts were compared with spring sown ones of the same genotypes during 2009-2010. We found, that the overwintered populations exhibited signifi cantly lower total alkaloid contents (1.065%) than the ones from spring sowing (1.479%). This tendency was proved for each of the individual alkaloid compounds morphine, codeine, thebaine nd narcotine, too. At the same time, maximum values in some individual samples of the overwintered plants reached similar or higher contents than the spring sown ones. Therefore it is supposed that even if gene frequency in direction for enhanced alkaloid synthesis might be larger in frost sensitive ecotypes, the potential for breeding high alkaloid accumulating cultivars exists also among frost tolerant genotypes
Pressure-induced transition from the dynamic to static Jahn-Teller effect in (PhP)IC
High-pressure infrared transmission measurements on \PhC60 were performed up
to 9 GPa over a broad frequency range (200 - 20000 cm) to monitor the
vibrational and electronic/vibronic excitations under pressure. The four
fundamental T modes of \C60a\ are split into doublets already at the
lowest applied pressure and harden with increasing pressure. Several cation
modes and fullerene-related modes split into doublets at around 2 GPa, the most
prominent one being the G mode. The splitting of the vibrational modes
can be attributed to the transition from the dynamic to static Jahn-Teller
effect, caused by steric crowding at high pressure. Four absorption bands are
observed in the NIR-VIS frequency range. They are discussed in terms of
transitions between LUMO electronic states in \C60a, which are split because of
the Jahn-Teller distortion and can be coupled with vibrational modes. Various
distortions and the corresponding symmetry lowering are discussed. The observed
redshift of the absorption bands indicates that the splitting of the LUMO
electronic states is reduced upon pressure application.Comment: 10 pages, 17 figure
Lying Your Way to Better Traffic Engineering
To optimize the flow of traffic in IP networks, operators do traffic
engineering (TE), i.e., tune routing-protocol parameters in response to traffic
demands. TE in IP networks typically involves configuring static link weights
and splitting traffic between the resulting shortest-paths via the
Equal-Cost-MultiPath (ECMP) mechanism. Unfortunately, ECMP is a notoriously
cumbersome and indirect means for optimizing traffic flow, often leading to
poor network performance. Also, obtaining accurate knowledge of traffic demands
as the input to TE is elusive, and traffic conditions can be highly variable,
further complicating TE. We leverage recently proposed schemes for increasing
ECMP's expressiveness via carefully disseminated bogus information ("lies") to
design COYOTE, a readily deployable TE scheme for robust and efficient network
utilization. COYOTE leverages new algorithmic ideas to configure (static)
traffic splitting ratios that are optimized with respect to all (even
adversarially chosen) traffic scenarios within the operator's "uncertainty
bounds". Our experimental analyses show that COYOTE significantly outperforms
today's prevalent TE schemes in a manner that is robust to traffic uncertainty
and variation. We discuss experiments with a prototype implementation of
COYOTE
Possible observation of phase coexistence of the fractional quantum Hall liquid and a solid
We have measured the magnetoresistance of a very low density and an extremely
high quality two-dimensional hole system. With increasing magnetic field
applied perpendicularly to the sample we observe the sequence of insulating,
fractional quantum Hall liquid, and insulating phases. In both of the
insulating phases in the vicinity of the filling the
magnetoresistance has an unexpected oscillatory behavior with the magnetic
field. These oscillations are not of the Shubnikov-de Haas type and cannot be
explained by spin effects. They are most likely the consequence of the
formation of a new electronic phase which is intermediate between the
correlated Hall liquid and a disorder pinned solid.Comment: 5 pages, 4 figure
A Los Angeles és Duarte galaktóz-1-foszfát-uridil-transzferáz-variánsok allélgyakorisága a magyar populációban
Classical galactosaemia is an autosomal recessively inherited disorder caused by deficient activity of the enzyme galactose-1-phosphate uridyltransferase (GALT), which can be detected by newborn screening. The p.N314D mutation defines two variant forms of the GALT enzyme, the Los Angeles and Duarte, depending on the presence of additional base changes. Aim: The aim of our study was to analyze a healthy Hungarian population for the frequencies of the Los Angeles and Duarte galactose-1-phosphate uridyltransferase variant alleles. Methods: DNA samples from 100 subjects were analyzed by polymerase chain reaction, followed by digestion with restriction endonucleases. Results: The frequencies of the p.N314D, the Los Angeles and the Duarte variants were 11.5%, 2.5% and 9%, respectively. Conclusions: The allele frequencies of the Los Angeles and Duarte variant alleles in the Hungarian population correlate well with the allele frequencies in other healthy Caucasian populations
Vortex solutions in axial or chiral coupled non-relativistic spinor- Chern-Simons theory
The interaction of a spin 1/2 particle (described by the non-relativistic
"Dirac" equation of L\'evy-Leblond) with Chern-Simons gauge fields is studied.
It is shown, that similarly to the four dimensional spinor models, there is a
consistent possibility of coupling them also by axial or chiral type currents.
Static self dual vortex solutions together with a vortex-lattice are found with
the new couplings.Comment: Plain TEX, 10 page
Adatok és adatforrások integrációja a pragmatikai kutatásban
A tanulmány különböző adatforrások integrációját vizsgálja a szinkrón és a történeti pragmatika kutatási gyakorlatában. A nyelvhasználat tanulmányozásának e két, meghatározóan korpuszalapú területén készített esettanulmányainkban amellett érvelünk, hogy a hagyományosan korpuszadatoknak tekintett információk valójában integrált adatforrásból származó plauzibilis kijelentések, továbbá hogy a pragmatika kutatási módszerei között a gyakorlatban elmosódnak a határok. A tanulmány konklúziója, hogy még az elsődlegesen korpuszon alapuló kutatási folyamatokban is számos, különböző forrásból származó információt integrálunk. Következésképpen a korpusz nem tekinthető kizárólagos adatforrásnak, hiszen további forrásokkal egészül ki, úgymint pl. a kutató nyelvi intuíciója, a korábbi kutatások eredményei, a kutatás elméleti kerete és számos következtetés
Temperature and pressure-induced spin-state transitions in LaCoO3
We report the continuous variation of the spin moment of cobalt in LaCoO3
across its temperature and pressure-induced spin transitions evidenced with
K\beta emission spectra. The first thermal transition is best described by a
transition to an orbitally nondegenerate intermediate spin (S=1) state. In
parallel, continuous redistribution of the 3d electrons is also indicated by
partial fluorescence yield X-ray absorption spectra. At high pressure, our
study confirms that the material becomes low spin between 40 and 70 kbar at
room temperature
A comparative analysis of the mutagenicity of platinum-containing chemotherapeutic agents reveals direct and indirect mutagenic mechanisms.
Platinum-based drugs are a mainstay of cancer chemotherapy. However, their mutagenic effect can increase tumour heterogeneity, contribute to the evolution of treatment resistance and also induce secondary malignancies. We coupled whole genome sequencing with phenotypic investigations on two cell line models to compare the magnitude and examine the mechanism of mutagenicity of cisplatin, carboplatin and oxaliplatin. Cisplatin induced significantly more base substitution mutations than carboplatin or oxaliplatin when used at equitoxic concentrations on human TK6 or chicken DT40 cells, and also induced the highest number of short insertions and deletions. The analysis of base substitution spectra revealed that all three tested platinum drugs elicit both a direct mutagenic effect at purine dinucleotides, and an indirect effect of accelerating endogenous mutagenic processes, whereas the direct mutagenic effect appeared to correlate with the level of DNA damage caused as assessed through histone H2AX phosphorylation and single-cell agarose gel electrophoresis, the indirect mutagenic effects were equal. The different mutagenicity and DNA-damaging effect of equitoxic platinum drug treatments suggest that DNA damage independent mechanisms significantly contribute to their cytotoxicity. Thus, the comparatively high mutagenicity of cisplatin should be taken into account in the design of chemotherapeutic regimens
- …