Search results for " polar"
showing 10 items of 1091 documents
Active lighting applied to three dimensional reconstruction of specular metallic surfaces by polarization imaging
2005
This thesis deals with a new automated tridimensional inspection system for specular metallic surfaces, based on polarization analysis. We first present an extension of the ‘Shape from Polarization' method for dielectric to metallic surfaces. After being reflected, an unpolarized light wave becomes partially linearly polarized, depending on the surface normal and on the refractive index of the media it impinges on. Hence, by measuring the polarization parameters of the reflected light, the surface normals are computed. The ambiguity concerning the normals orientation is solved here with a new active lighting system. Then, we describe and compare numerical methods for reconstructing the trid…
Tolerance and M2 (alternative) macrophage polarization are related processes orchestrated by p50 nuclear factor {kappa}B.
2009
Cells of the monocyte-macrophage lineage play a central role in the orchestration and resolution of inflammation. Plasticity is a hallmark of mononuclear phagocytes, and in response to environmental signals these cells undergo different forms of polarized activation, the extremes of which are called classic or M1 and alternative or M2. NF-kappaB is a key regulator of inflammation and resolution, and its activation is subject to multiple levels of regulation, including inhibitory, which finely tune macrophage functions. Here we identify the p50 subunit of NF-kappaB as a key regulator of M2-driven inflammatory reactions in vitro and in vivo. p50 NF-kappaB inhibits NF-kappaB-driven, M1-polariz…
Spectral dynamics of incoherent waves with a noninstantaneous nonlinear response
2013
We study the influence of a constant background noise on the dynamics of spectral incoherent solitons, which are incoherent structures sustained by a noninstantaneous (Raman-like) nonlinearity. As the level of the noise background increases, the incoherent wave enters a novel nonlinear regime characterized by oscillatory dynamics of the incoherent spectrum, which develop within a spectral cone during the propagation. In contrast to the conventional Raman-like spectral red shift, such incoherent spectral dynamics can be characterized by a significant spectral blue shift. On the basis of the kinetic wave theory, we derive explicit analytical expressions of these incoherent oscillatory spectra…
Characterization of high-temperature performance of cesium vapor cells with anti-relaxation coating
2017
© 2017 Author(s). Vapor cells with antirelaxation coating are widely used in modern atomic physics experiments due to the coating's ability to maintain the atoms' spin polarization during wall collisions. We characterize the performance of vapor cells with different coating materials by measuring longitudinal spin relaxation and vapor density at temperatures up to 95 °C. We infer that the spin-projection-noise-limited sensitivity for atomic magnetometers with such cells improves with temperature, which demonstrates the potential of antirelaxation coated cells in applications of future high-sensitivity magnetometers.
Krāsu centru spinu polarizācijas ar gaismu modelēšana dimantu kristālos
2017
Pateicoties krāsu centru dimanta kristālos struktūrai, pastāv iespēja polarizēt to spinus ar gaismu, elektrisko vai magnētisko lauku, kas var būt noderīgs, piemēram, vājo lauku detektēšanā. Darbā tika izstrādāts matemātisks modelis krāsu centra spina mijiedarbībai ar lāzera starojumu ārējā magnētiskā un mikroviļņu lauka klātbūtnē, kas palīdzēs saprast dimanta kristālos notiekošo procesu dinamiku. Modelis tika realizēts Wolfram Mathematica programmas ietvaros un pārbaudīts, variējot to parametrus, kā arī simulācijas rezultāti bija salīdzināti ar reāliem optiski detektētās magnētiskās rezonanses spektriem.
Krāsu centru dimanta kristālā kodola spina polarizācija magnētiskajā laukā
2018
Šajā darbā tiek apskatīta lāzera un mikroviļņu lauku ietekme uz krāsu centriem dimanta kristālā, kuri atrodas konstantā magnētiskā laukā. Pēc iepazīšanās ar kvantu mehānikas matemātisko struktūru un galvenajām atvērto sistēmu modelēšanas metodēm, tiek veikti skaitliski aprēķini, kuri ļauj iegūt optiski detektētās magnētiskās rezonanses spektrus un krāsu centru elektronu un kodolu spinu polarizācijas raksturīgos lielumus. Iegūtie rezultāti tiek salīdzināti ar literatūrā pieejamajiem eksperimentālajiem datiem.
All polarization-maintaining assively mode-locked yb-doped fiber laser : pulse compression using an anomalous polarization-maintaining photonic cryst…
2019
We report the generation of short pulses at 1 μm using an all-polarization-maintaining (PM) fiber configuration. The pulses are provided by an all normal-dispersion Fabry-Perot Yb-doped cavity and are compressed with an anomalous polarization-maintaining photonic crystal fiber (PM PCF). Opposed to standard configurations; here the filtering action is solely performed by the finite bandwidth of the gain medium. The laser generates 8 ps width sech 2 profile pulses at 1046.8 nm with a −10 dB bandwidth of 5.9 nm. After compression using the PM PCF, pulses with an FWHM of 3 ps were obtained, limited by the actual value of the available anomalous dispersion. We also report the changes in the outp…
All-Fiber Laser With Intracavity Acousto-Optic Dynamic Mode Converter for Efficient Generation of Radially Polarized Cylindrical Vector Beams
2017
We report an all-fiber laser that emits a radially polarized cylindrical vector beam (CVB) at 1 μm based on an intracavity acousto-optic mode converter. We efficiently generate the CVB, taking advantage of the acousto-optic coupling from the HE11 mode to the TM01 mode in a two-mode fiber. The laser can be switched from emitting a Gaussian-like beam to a radially polarized CVB. Radially polarized CVBs with modal and polarization purities >98% and a maximum power of 65 mW were generated.
Macrophages as an Emerging Source of Wnt Ligands: Relevance in Mucosal Integrity
2019
The Wnt signaling pathway is a conserved pathway involved in important cellular processes such as the control of embryonic development, cellular polarity, cellular migration, and cell proliferation. In addition to playing a central role during embryogenesis, this pathway is also an essential part of adult homeostasis. Indeed, it controls the proliferation of epithelial cells in different organs such as intestine, lung, and kidney, and guarantees the maintenance of the mucosa in physiological conditions. The origin of this molecular pathway is the binding between Wnt ligands (belonging to a family of 19 different homologous secreted glycoproteins) and their specific membrane receptors, from …
Evolució de la sintaxi dels contextos de polaritat negativa en castellà i català
2007
In this paper we would like to compare the evolution of the syntax of polar contexts in Catalan and Spanish. By doing so, it would be possible to explain the greater syntactic disponibility of Catalan quantifiers and the important constraints for the same class of words in Spanish. After presenting in the first section the main theoretical questions about polarity in natural languages, we will describe in the second section the syntax of corresponding contexts in Middle Ages for both languages. Then, in the third section we will attend to the evolution towards current situation in order to understand the nature of modern differences between Catalan and Spanish on this area of their syntax.