510 research outputs found
Time-Delay Polaritonics
Non-linearity and finite signal propagation speeds are omnipresent in nature,
technologies, and real-world problems, where efficient ways of describing and
predicting the effects of these elements are in high demand. Advances in
engineering condensed matter systems, such as lattices of trapped condensates,
have enabled studies on non-linear effects in many-body systems where exchange
of particles between lattice nodes is effectively instantaneous. Here, we
demonstrate a regime of macroscopic matter-wave systems, in which ballistically
expanding condensates of microcavity exciton-polaritons act as picosecond,
microscale non-linear oscillators subject to time-delayed interaction. The ease
of optical control and readout of polariton condensates enables us to explore
the phase space of two interacting condensates up to macroscopic distances
highlighting its potential in extended configurations. We demonstrate
deterministic tuning of the coupled-condensate system between fixed point and
limit cycle regimes, which is fully reproduced by time-delayed coupled
equations of motion similar to the Lang-Kobayashi equation
Nanosized Sodium-Doped Lanthanum Manganites: Role of the Synthetic Route on their Physical Properties
In this paper we present the results of the synthesis and characterisation of
nanocrystalline La1-xNaxMnO3+delta samples. Two synthetic routes were employed:
polyacrylamide-based sol-gel and propellant synthesis. Pure, single phase
materials were obtained with grain size around 35 nm for the sol-gel samples
and around 55 nm for the propellant ones, which moreover present a more broaden
grain size distribution. For both series a superparamagnetic behaviour was
evidenced by means of magnetisation and EPR measurements with peculiar features
ascribable to the different grain sizes and morphology. Preliminary
magnetoresistivity measurements show enhanced low-field (< 1 T)
magnetoresistance values which suggest an interesting applicative use of these
manganites.Comment: 31 Pages 10 Figures to appear in Chem. Mate
Zero Order Estimates for Analytic Functions
The primary goal of this paper is to provide a general multiplicity estimate.
Our main theorem allows to reduce a proof of multiplicity lemma to the study of
ideals stable under some appropriate transformation of a polynomial ring. In
particular, this result leads to a new link between the theory of polarized
algebraic dynamical systems and transcendental number theory. On the other
hand, it allows to establish an improvement of Nesterenko's conditional result
on solutions of systems of differential equations. We also deduce, under some
condition on stable varieties, the optimal multiplicity estimate in the case of
generalized Mahler's functional equations, previously studied by Mahler,
Nishioka, Topfer and others. Further, analyzing stable ideals we prove the
unconditional optimal result in the case of linear functional systems of
generalized Mahler's type. The latter result generalizes a famous theorem of
Nishioka (1986) previously conjectured by Mahler (1969), and simultaneously it
gives a counterpart in the case of functional systems for an important
unconditional result of Nesterenko (1977) concerning linear differential
systems. In summary, we provide a new universal tool for transcendental number
theory, applicable with fields of any characteristic. It opens the way to new
results on algebraic independence, as shown in Zorin (2010).Comment: 42 page
Grapevine DNA polymorphisms revealed by microsatellite-derived markers from soybean and rice
We report detection of DNA polymorphisms in grapevine by the use of microsatellite-flanking primer pairs from soybean and rice. These “cross species” microsatellite-derived markers were checked for their inheritance patterns in controlled grapevine crosses. They produced multiple bands that segregated and can be scored as individual genetic markers of dominant type. Employed in genetic mapping studies they offer advantages such as improved reproducibility in comparison to commonly used multi-locus marker systems like RAPDs and AFLPs.
Molecular-Level Understanding of the Ro-vibrational Spectra of NO in Gaseous, Supercritical and Liquid SF and Xe
The transition between the gas-, supercritical-, and liquid-phase behaviour
is a fascinating topic which still lacks molecular-level understanding. Recent
ultrafast two-dimensional infrared spectroscopy experiments suggested that the
vibrational spectroscopy of NO embedded in xenon and SF as solvents
provides an avenue to characterize the transitions between different phases as
the concentration (or density) of the solvent increases. The present work
demonstrates that classical molecular dynamics simulations together with
accurate interaction potentials allows to (semi-)quantitatively describe the
transition in rotational vibrational infrared spectra from the P-/R-branch
lineshape for the stretch vibrations of NO at low solvent densities to the
Q-branch-like lineshapes at high densities. The results are interpreted within
the classical theory of rigid-body rotation in more/less constraining
environments at high/low solvent densities or based on phenomenological models
for the orientational relaxation of rotational motion. It is concluded that
classical MD simulations provide a powerful approach to characterize and
interpret the ultrafast motion of solutes in low to high density solvents at a
molecular level
Directional planar antennae in polariton condensates
We report on the realization of all-optical planar microlensing for
exciton-polariton condensates in semiconductor microcavities. We utilize
spatial light modulators to structure a nonresonant pumping beam into a
planoconcave lens-shape focused onto the microcavity plane. When pumped above
condensation threshold, the system effectively becomes a directional polariton
antenna, generating an intense focused beam of coherent polaritons away from
the pump region. The effects of pump intensity, which regulates the interplay
between gain and blueshift of polaritons, as well as the geometry of
lens-shaped pump are studied and a strategy to optimize the focusing of the
condensate is proposed. Our work underpins the feasibility to guide nonlinear
light in microcavities using nonresonant excitation schemes, offering
perspectives on optically reprogrammable on-chip polariton circuitry
CAR-T cell. the long and winding road to solid tumors
Adoptive cell therapy of solid tumors with reprogrammed T cells can be considered the "next generation" of cancer hallmarks. CAR-T cells fail to be as effective as in liquid tumors for the inability to reach and survive in the microenvironment surrounding the neoplastic foci. The intricate net of cross-interactions occurring between tumor components, stromal and immune cells leads to an ineffective anergic status favoring the evasion from the host's defenses. Our goal is hereby to trace the road imposed by solid tumors to CAR-T cells, highlighting pitfalls and strategies to be developed and refined to possibly overcome these hurdles
A 'Regent' pedigree update: ancestors, offspring and their confirmed resistance loci
'Regent' is the fungal resistant grapevine cultivar with the highest acreage in Germany and an important resistance donor in international breeding programs. It carries the resistance loci Rpv3.1 as well as Ren3 and Ren9 against downy and powdery mildew, respectively. As the parents of 'Chambourcin', the resistant paternal ancestor of 'Regent', did not coincide with the breeder's information, the germplasm repository of JKI Geilweilerhof was screened to find the missing ancestors. SSR marker analysis revealed that 'Joannes Seyve 11369' and 'Plantet' are the true parents of 'Chambourcin' and not 'Seyve Villard 12-417' and 'Chancellor'. Furthermore, the origin of the resistance loci Ren3 and Ren9 could be traced back to the genotypes 'Seibel 4614' and 'Munson'. Since the breeder Hermann Jaeger mentioned 'Munson' as a direct descendant of Vitis aestivalis Michx. var. linsecomii (Buckley) L. H. Bailey and Vitis rupestris Scheele, one of these wild species might have been the donor of the loci
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