Search results for "Coherence"

Alignement moléculaire par impulsions laser ultrabrèves : Mesures & Applications

2009

The interaction of an intense ultrashort laser pulse with a molecular sample leads, after the end of the pulse, to molecular alignment at specific time under field-free conditions. This thesis is dedicated to the measurements and applications of this effect. The degree of alignment is determined through the variation of the refractive index induced by the rearrangement of the molecular dipoles. A two-dimensional technique allowing to measure molecular alignment on a single-shot basis is reported in this document. The alignment is then exploited in order to determine physical quantities which are usually difficult to estimate through others methods. The "cross-defocusing technique" has been …

Temporal coherence in mirrorless optical parametric oscillators

2012

International audience; One of the unique features of mirrorless optical parametric oscillators based on counterpropagating three-wave interactions is the narrow spectral width of the wave generated in the backward direction. In this work, we in- vestigate experimentally and numerically the influence that a strong phase modulation in the pump has on the spectral bandwidths of the parametric waves and on the efficiency of the nonlinear interaction. The effects of group-velocity mismatch and group-velocity dispersion are elucidated. In particular, it is shown that the substan- tial increase in temporal coherence of the backward-generated wave can be obtained even for pumping with a temporally…

Electronic implementation of a non-linear oscillator subjected to noise : application to the modeling of neuronal information coding

2011

We study the nonlinear FitzHugh-Nagumo model witch describes the dynamics of excitable neural element. It is well known that this system exhibits three different possible responses. Indeed, the system can be mono-stable, oscillatory or bistable. In the oscillatory regime, the system periodically responds by generating action potential. By contrast, in the mono-stable state the system response remains constant after a transient. Under certain conditions, the system can undergo a bifurcation between the stable and the oscillatory regime via the so called Andronov-Hopf bifurcation. In this Phd thesis, we consider the FitzHugh-Nagumo model in the stable state, that is set near the Andronov-Hopf…

Evaluation of the iridocorneal angle with accommodation using optical coherence tomography

2017

The changes in the iridocorneal angle structure during accommodation are assessed by means of anterior segment optical coherence tomography. Thirteen right eyes were included in the study. The device used for the measurement was the Visante® omni system. The stimuli were set up at different vergences (0.0 D, -1.5 D, and -3.0 D). The angle opening distance 500 and 750, the trabecular iris space area 500 and 750, and the scleral spur angle parameters were assessed at the nasal and temporal regions. The results in the iridotrabecular angle comparing the three accommodative states of the eye did not yield any statistically significant difference at nasal or temporal angle sections. In light of …

Evaluation of the relationship between some mental state parameters and the quality of life in patients with allergic diseases

2022

Aim. The aim of the study was to assess the relationship between symptoms of depression,the level of sense of coherence (SOC) and the quality of life in patients with allergic diseases. Material. The study involved 50 bronchial asthma patients, 72 patients with seasonal allergic rhinitis, and 48 patients with atopic dermatitis. The control group consisted of 50 healthy volunteers. Methods. The mental status and quality of life were assessed by questionnaires: Short Form-36 Health Status Survey (SF-36), Beck Depression Inventory (BDI), Sense of Coherence-29 (SOC-29. Results. Mean depression severity values were higher in allergic rhinitis patients and atopic dermatitis patients than in the c…

Algorithms for the Automated Analysis of Age-Related Macular Degeneration Biomarkers on Optical Coherence Tomography: A Systematic Review

2017

PURPOSE To assess the quality of optical coherence tomography (OCT) grading algorithms for retinal biomarkers of age-related macular degeneration (AMD). METHODS Following a systematic review of the literature data on detection and quantification of AMD retinal biomarkers by available algorithms were extracted and descriptively synthesized. Algorithm quality was assessed using a modified version of the Quality Assessment of Diagnostic Accuracy Studies 2 checklist with a focus on accuracy against established reference standards and risk of bias. RESULTS Thirty five studies reporting computer-aided diagnosis (CAD) tools for qualitative analysis or algorithms for quantitative analysis were iden…

Increased Gamma Connectivity in the Human Prefrontal Cortex during theBereitschaftspotential

2017

The Bereitschaftspotential (BP) is a slow negative cortical potential preceding voluntary movement. Since movement preparation is dependent upon the synchronous activity of a variety of neurons, BP may develop through the exchange of information among motor-related neurons. However, the relationship between BP and information flow is not yet well-known. In the present study, we aimed to investigate how the connectivity in the prefrontal cortex (PFC) changes during the occurrence of BP. Electrocorticography (ECoG) was recorded in five patients with epilepsy. The subjects performed self-paced hand grasping. We compared the intraregional connectivity between PFC and non-PFC regions using parti…

Statistical Adhockeries Are No Criteria for Legal Decisions—The Case of the Expert Medical Report on the Assessment of Urine Specimens Collected Amon…

2019

Three New Medicagenic Acid Saponins from Polygala micranthaGuill. & Perr.

2011

Three new medicagenic acid saponins, micranthosides A–C (1–3), were isolated from the roots of Polygala micranthaGuill. & Perr., along with six known presenegenin saponins. Their structures were elucidated on the basis of extensive 1D- and 2D-NMR experiments (1H, 13C, DEPT, COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry as 3-O-β-D-glucopyranosylmedicagenic acid 28-[O-β-D-galactopyranosyl-(14)-O-β-D-xylopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-β-D-fucopyranosyl] ester (1), 3-O-β-D-glucopyranosylmedicagenic acid 28-[O-6-O-acetyl-β-D-galactopyranosyl-(14)-O-β-D-xylopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-β-D-fucopyranosyl] ester (2), and 3-O-{O-β-D-glucopyranosyl-(13)-O-[β-D-gluc…

Valodniecības aspektu loma žurnāla Forbes rakstu mērķauditorijas sasniegšanā

2018

Šīs disertācijas temats ir lingvistisko un citu aspektu lietojums lasītāju mērķa auditorijas sasniegšanai Forbes žurnāla rakstos. Kopumā, ir novērojams trūkums attiecībā uz pētījumiem, kas saistīti ar lasītāju mērķauditoriju kā galveno faktoru rakstisku darbu veidošanā. Sekojoši, trūkst arī informācijas par tiem faktoriem un instrumentiem, kuru lietošana palīdz sasniegt mērķauditoriju. Tādēļ, šī darba mērķis ir noteikt kādi lingvistiskie un ar tiem saistītie kontekstuālie aspekti tiek izmantoti lasītāju mērķauditorijas sasniegšanā žurnāla Forbes rakstos, kā arī, izanalizēt, kāda ir šo aspektu ietekme uz mērķa auditorijas sasniegšanu. Lai analizētu būtiskās žurnāla iezīmes un autora viedokli…