559 research outputs found
Masses and Interactions of q-Fermionic Knots
The q-electroweak theory suggests a description of elementary particles as
solitons labelled by the irreducible representations of SU_q(2). Since knots
may also be labelled by the irreducible representations of SU_q(2), we study a
model of elementary particles based on a one-to-one correspondence between the
four families of Fermions (leptons, neutrinos, (-1/3) quarks, (2/3) quarks) and
the four simplest knots (trefoils). In this model the three particles of each
family are identified with the ground and first two excited states of their
common trefoil. Guided by the standard electroweak theory we calculate
conditions restricting the masses of the fermions and the interactions between
them.
In its present form the model predicts a fourth generation of fermions as
well as a neutrino spectrum. The same model with q almost equal to 1 is
compatible with the Kobayashi-Maskawa matrix. Depending on the test of these
predictions, the model may be refined.Comment: 40 pages, 2 figures, latex forma
Hierarchically-structured metalloprotein composite coatings biofabricated from co-existing condensed liquid phases
Complex hierarchical structure governs emergent properties in biopolymeric materials; yet, the material processing involved remains poorly understood. Here, we investigated the multi-scale structure and composition of the mussel byssus cuticle before, during and after formation to gain insight into the processing of this hard, yet extensible metal cross-linked protein composite. Our findings reveal that the granular substructure crucial to the cuticleâs function as a wear-resistant coating of an extensible polymer fiber is pre-organized in condensed liquid phase secretory vesicles. These are phase-separated into DOPA-rich proto-granules enveloped in a sulfur-rich proto-matrix which fuses during secretion, forming the sub-structure of the cuticle. Metal ions are added subsequently in a site-specific way, with iron contained in the sulfur-rich matrix and vanadium coordinated by DOPA-catechol in the granule. We posit that this hierarchical structure self-organizes via phase separation of specific amphiphilic proteins within secretory vesicles, resulting in a meso-scale structuring that governs cuticle function
Molecular characterization of different isolates of CpGV and their activity against Cydia molesta
Biologische Kontrolle von Eulenraupen im Kohl mittels Baculoviren
Baculoviren sind als hoch selektive biologische Kontrollagenzien fĂŒr Kohleulenraupen (Mamestra brassicae) seit lĂ€ngerem bekannt und ihre gute Wirksamkeit wurde schon in verschiedenen GewĂ€chshaus- und Freilandversuchen nachgewiesen. Um die Kontrollsituation von Kohleulenraupen im ökologischen GemĂŒseanbau insbesondere bei niedrigen Temperaturen zu verbessern, wurden die eulenpathogenen Mamestra brassicae Nukelopolyhedrovirus (MbMNPV) und Mamestra configurata Nukleopolyhedrovirus (MacoNPV-A) als mögliche Kontrollagentien geprĂŒft. Es konnte gezeigt werden, dass auch MacoNPV-A fĂŒr M.brassicae pathogen ist. In vergleichenden Bioassays bei 24°C zeigten MbMNPV und MacoNPV-A keinen signifikanten Unterschied hinsichtlich ihrer biologischen AktivitĂ€t gegenĂŒber M.brassicae. In weiteren Bioassays wurden die konzentrationsabhĂ€ngige MortalitĂ€t von M.brassicae im 2. Larvenstadium sowie die gefressene BlattflĂ€che bei 24, 20, 16 und 12°C bestimmt. Im Vergleich zu 24 und 20°C waren die mittleren Letalkonzentrationen bei 16 und 12°C 100 bzw. 1000fach höher. FĂŒr eine mittlere Reduktion der konsumierten BlattflĂ€che waren hingegen bei Temperaturen unter 20°C 10 bis 100fach höhere Konzentrationen notwendig. Durch die Neuformulierung von MbMNPV (Probis GmbH, Wiernsheim) konnte eine Wirkungssteigerung im Vergleich zu der nicht formulierten Virussuspension im Bioassay erzielt werden. In einem Freilandtest mit kĂŒnstlicher Infestation in Kohlrabi konnte eine weitere Steigerung des Wirkungsgrades durch die Kombination mit dem Bacillus thuringiensis PrĂ€parat XenTariÂź im Vergleich zur Einzelapplikation der beiden PrĂ€parate erreicht werden. Eine breite Freilandtestung der Baculoviren-PrĂ€paraten gegen Kohlraupen bei kĂŒhler Witterung als EinzelprĂ€parat und in Kombination mit Bacillus thuringiensis PrĂ€paraten sowie neuester Applikationstechnik fĂŒr Ober- und Unterblattbehandlung wird empfohlen
Mitigation of atmospheric perturbations and solid Earth movements in a TerraSAR-X time-series
The TerraSAR-X (TSX) synthetic aperture radar (SAR) marks the recent emergence of a new generation of spaceborne radar sensors that can for the first time lay claim to localization accuracies in the sub-meter range. The TSX platformâs extremely high orbital stability and the sensorâs hardware timing accuracy combine to enable direct measurements of atmospheric refraction and solid Earth movements. By modeling these effects for individual TSX acquisitions, absolute pixel geolocation accuracy on the order of several centimeters can be achieved without need for even a single tiepoint. A 16-month time series of images was obtained over a fixed test site, making it possible to validate both an atmospheric refraction and a solid Earth tide model, while at the same time establishing the instrumentâs long-term stability. These related goals were achieved by placing trihedral corner reflectors (CRs) at the test site and estimating their phase centers with centimeter-level accuracy using differential GPS (DGPS). Oriented in pairs toward a given satellite track, the CRs could be seen as bright âpointsâ in the images, providing a geometric reference set. SAR images from the high-resolution spotlight (HS) mode were obtained in alternating ascending and descending orbit configurations. The highest-resolution products were selected for their small sample dimensions, as positions can be more precisely determined. Based on the delivered product annotations, the CR image positions were predicted, and these predictions were compared with their measured image positions both before and after compensation for atmospheric refraction and systematic solid Earth deviations. It was possible to show that when the atmospheric distortion and Earth tides are taken into account, the TSX HS products have geolocation accuracies far exceeding the specified requirements. Furthermore, this accuracy was maintained for the duration of the 16-month test period. It could be demonstrated that with a correctly calibrated sensor, and after accounting for atmospheric and tidal effects, tiepoint-free geolocation is possible with TSX with an absolute product accuracy of about 5 cm
Conseil-santé dans la médecine de premier recours, partie 2
Les maladies non transmissibles (MNT, en anglais «non-communicable diseases») ont gagné du terrain dans le monde entier. Les approches de conseil fourni au cabinet médical ont déjà été présentées dans un premier article. Le présent article se
consacre aux conditions permettant Ă ces approches de dĂ©ployer leur efficacitĂ© au niveau de la population. Ceci est illustrĂ© sur la base des programmes suisses actuels «Vivre sans tabac», PAPRICA et «Coaching Santé» ainsi que de lâexemple historique «Ăa dĂ©bouche sur quoi?»
Untersuchungen zur Populationsgenetik der Minderempfindlichkeit des Apfelwicklers gegenĂŒber Cydia pomonella Granulovirus (CpGV)
The Codling moth granulovirus (Cydia pomonella granulovirus, CpGV, Baculoviridae) is one of the most important bio control agents of the codling moth in apple production. Since 2003, codling moth populations have been observed in Germany and France, which show an up to thousand fold decreased susceptibility to CpGV. A spread of this phenomenon is a severe threat to the efficient control of the codling moth, particularly in organic farming. In order to prevent this development, investigations on the popula-tion genetics of codling moth populations in Germany were initiated to assess the baseline susceptibilities of selected populations. Furthermore, the genetic and biologi-cal background of resistance of the codling moth to CpGV are being elucidated by crossing susceptible and low susceptible codling moth populations. These investiga-tions will help to develop new control strategies or to restore high susceptibility to-wards CpGV.
Mapping of traits involved in resistance will be performed. Involved loci will be identi-fied with the help of amplified fragment length polymorphism (AFLP). Loci coupled with susceptibility can help to elucidate resistance mechanisms. Analysis of comple-mentary DNA amplified fragment length polymorphism (cDNA-AFLP) will be per-formed to display differences in expression rate of particular genes. If there are differ-ences between sensitive and non-sensitive strains, the genes will be isolated and sequenced. Putative sequence homologies give the direction of the functional sense of the mentioned gene and further conclusion of the mechanisms of the susceptibility of CpGV
A toy model of the five-dimensional universe with the cosmological constant
A value of the cosmological constant in a toy model of the five-dimensional
universe is calculated in such a manner that it remains in agreement with both
astronomical observations and the quantum field theory concerning the
zero-point fluctuations of the vacuum. The (negative) cosmological constant is
equal to the inverse of the Planck length squared, which means that in the toy
model the vanishing of the observed value of the cosmological constant is a
consequence of the existence of an energy cutoff exactly at the level of the
Planck scale. In turn, a model for both a virtual and a real
particle-antiparticle pair is proposed which describes properly some energetic
properties of both the vacuum fluctuations and created particles, as well as it
allows one to calculate the discrete "bare" values of an elementary-particle
mass, electric charge and intrinsic angular momentum (spin) at the energy
cutoff. The relationships between the discussed model and some phenomena such
as the Zitterbewegung and the Unruh-Davies effect are briefly analyzed, too.
The proposed model also allows one to derive the Lorentz transformation and the
Maxwell equations while considering the properties of the vacuum filled with
the sea of virtual particles and their antiparticles. Finally, the existence of
a finite value of the vacuum-energy density resulting from the toy model leads
us to the formulation of dimensionless Einstein field equations which can be
derived from the Lagrangian with a dimensionless (naively renormalized)
coupling constant.Comment: 52 pages, 1 figure; a post-final, rewritten version with a number of
new remarks and conclusion
Pharmacokinetics of oxycodone/naloxone and its metabolites in patients with end-stage renal disease during and between haemodialysis sessions
The pharmacokinetics of oxycodone in patients with end-stage renal disease (ESRD) requiring haemodialysis are largely unknown. Therefore, we investigated the pharmacokinetics of oxycodone/naloxone prolonged release and their metabolites in patients with ESRD during and between haemodialysis sessions.; Single doses of oxycodone/naloxone (5/2.5 or 10/5âmg) were administered in nine patients with ESRD using a cross-over design on the day of dialysis and on a day between dialysis sessions. Plasma, dialysate and urine concentrations of oxycodone, naloxone and their metabolites were determined up to 48âh post-dosing using a liquid chromatography-tandem mass spectrometry system.; Haemodialysis performed 6-10âh after dosing removed âŒ10% of the administered dose of oxycodone predominantly as unconjugated oxycodone and noroxycodone or conjugated oxymorphone and noroxymorphone. The haemodialysis clearance of oxycodone based on its recovery in dialysate was (mean ± SD) 8.4â±â2.1âL/h. The geometric mean (coefficient of variation) plasma elimination half-life of oxycodone during the 4-h haemodialysis period was 3.9âh (39%) which was significantly shorter than the 5.7âh (22%) without haemodialysis. Plasma levels of the active metabolite oxymorphone in its unconjugated form were very low.; Oxycodone is removed during haemodialysis. The pharmacokinetics including the relatively short half-life of oxycodone in patients with ESRD with or without haemodialysis and the absence of unconjugated active metabolites indicate that oxycodone can be used at usual doses in patients requiring dialysis
Intuitionistc probability and the Bayesian objection to dogmatism
Given a few assumptions, the probability of a conjunction is raised, and the probability of its negation is lowered, by conditionalising upon one of the conjuncts. This simple result appears to bring Bayesian confirmation theory into tension with the prominent dogmatist view of perceptual justification â a tension often portrayed as a kind of âBayesian objectionâ to dogmatism. In a recent paper, David Jehle and Brian Weatherson observe that, while this crucial result holds within classical probability theory, it fails within intuitionistic probability theory. They conclude that the dogmatist who is willing to take intuitionistic logic seriously can make a convincing reply to the Bayesian objection. In this paper, I argue that this conclusion is premature â the Bayesian objection can survive the transition from classical to intuitionistic probability, albeit in a slightly altered form. I shall conclude with some general thoughts about what the Bayesian objection to dogmatism does and doesnât show
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