Modeling of quasi-phase-matched cavity enhanced second harmonic generation

We propose a mean-field model to describe second harmonic generation in a resonator made of a material with zincblende crystalline structure. The model is obtained through an averaging of the propagation equations and boundary conditions. It considers the phase-mismatched terms, which act as an effective Kerr effect. We analyze the impact of the different terms on the steady state solutions, highlighting the competition between nonlinearities

Measuring the nonlinear refractive index of graphene using the optical Kerr effect method

© 2016 Optical Society of America.By means of the ultrafast optical Kerr effect method coupled to optical heterodyne detection (OHD-OKE), we characterize the third-order nonlinear response of graphene and compare it to experimental values obtained by the Z-scan method on the same samples. From these measurements, we estimate a negative nonlinear refractive index for monolayer graphene, n2 = -1.1 × 10-13 m2/W. This is in contradiction to previously reported values, which leads us to compare our experimental measurements obtained by the OHD-OKE and the Z-scan method with theoretical and experimental values found in the literature and to discuss the discrepancies, taking into account parameters such as doping

Total sleep deprivation alters endothelial function in rats: a nonsympathetic mechanism

STUDY OBJECTIVES: Sleep loss is suspected to induce endothelial dysfunction, a key factor in cardiovascular risk. We examined whether sympathetic activity is involved in the endothelial dysfunction caused by total sleep deprivation (TSD). DESIGN: TWO GROUPS: TSD (24-h wakefulness), using slowly rotating wheels, and wheel control (WC). PARTICIPANTS: Seven-month-old male Wistar rats. INTERVENTIONS: Pharmacological sympathectomy (reserpine, 5 mg/kg, intraperitoneal), nitric oxide synthase (NOS) inhibition (N (G)-nitro-L-arginine, 20 mg/kg, intraperitoneally 30 min before experiment) and cyclooxygenase (COX) inhibition (indomethacin, 5 mg/kg, intraperitoneally 30 min before experiment). MEASUREMENTS AND RESULTS: In protocol 1, changes in heart rate (HR) and blood pressure were continuously recorded in the sympathectomized and non-sympathectomized rats. Blood pressure and HR increased during TSD in non-sympathectomized rats. In protocol 2, changes in skin blood flow (vasodilation) were assessed in the sympathectomized and non-sympathectomized rats using laser-Doppler flowmetry coupled with iontophoretic delivery of acetylcholine (ACh), sodium nitroprusside (SNP), and anodal and cathodal currents. ACh- and cathodal current-induced vasodilations were significantly attenuated after TSD in non-sympathectomized and sympathectomized rats (51% and 60%, respectively). In protocol 3, ACh-induced vasodilation was attenuated after NOS and COX inhibition (66% and 49%, respectively). Cathodal current-induced vasodilation decreased by 40% after COX inhibition. In TSD compared to WC a decrease in ACh-induced vasodilation was still observed after COX inhibition. No changes in SNP- and anodal current-induced vasodilation were detected. CONCLUSION: These results demonstrate that total sleep deprivation induces a reduction in endothelial-dependent vasodilation. This endothelial dysfunction is independent of blood pressure and sympathetic activity but associated with nitric oxide synthase and cyclooxygenase pathway alterations

Photonic coherent state transfer with Hamiltonian dynamics

We report the observation of near-perfect light wave transfer by emulating quantum state transfer on a lattice with Hamiltonian dynamics, i.e., time-dependent intersite couplings. The structure transferring a single waveguide ex-citation over 11 sites with a fidelity of 0.93 works for classical light as well as single photons. As our implementation of perfect quantum state transfer uses a photonic setting, we introduce polarization as a new degree of freedom to the transport protocol. We demonstrate rotation operations of up to 40 ° on polarization during state transfer. © 201

Recomendaciones para mejorar la práctica odontológica

Introduction.- The stomatologic alterations have a high incidence according with World Health Organization. In Mexico about 90% of the population have caries. Objective.- To identify principal conflicts for odontologic attention observed in the complaints received in the CONAMED, and to generate recommendations directed to improve the quality of the odontology practice Methodology.- There was obtained information about the odontology complaints received in the CONAMED (January 2001 to October 2002). Once elaborated the recommendations were submitted to a Group of External Validation integrated by expert in the area. Results.� It were analyzed 177 complaints; 63.3 % corresponded to women and 36.7 % to men. The most affected age group patients was 25-44 years old with 35% of cases; 91 % of complaints was of private services. The most frequent causes of complaint were related to the treatment in 75.7 % of cases. The principal procedures were: 25.6 % of orthodontics y 24.4% prothesis. Principal modality of conclusion of the complaints was the conciliation (53.1 %). In a special sub-analysis of cases, malpractice was present in 43% of cases. Likewise the principal origin of identified problems were related with lack of communication or problems of communication between health personnel an their patients. Conclusions.- Factors identified in the complaints are related to the lack of communication among the professional of the mouth health and patient, false expectations of the patients and to the breach of obligations, The factors identified in the complaints, are related to lack of communication among health personnel and their patients, false expectations of the patients and with the breach of obligations, they were considered in recommendations.Introducción.- Las alteraciones estomatológicas tienen una alta incidencia de acuerdo con la Organización Mundial de la Salud, en México se estima que 90% de la población padece caries. Objetivo.- Identificar las principales conflictos por atención odontológica, manifestados en las quejas recibidas en la CONAMED, identificar sus principales características y emitir recomendaciones dirigidas a mejorar la calidad de la práctica odontológica. Metodología.- Se obtuvo la información sobre las quejas recibidas en la CONAMED del área de Odontología (enero de 2001 a octubre de 2002), una vez que se concluyó el análisis de las quejas, se elaboraron una serie de recomendaciones que fueron sometidas a un proceso de validación interna y posteriormente a una validación externa que fue realizada por expertos en el área. Resultados.- Se analizaron 177 quejas; 63.3% correspondieron a mujeres y 36.7% a hombres. El grupo de edad más afectado fue el de 25-44 años con 35% de los casos; 91% de quejas fueron de servicios privados. Los motivos de queja más frecuentes estaban relacionados con el tratamiento en 75.7% de los casos. Los principales procedimientos realizados fueron: 25.6% de ortodoncia, 24.4% prótesis y 13.3%. Las principal modalidad de conclusión de las quejas fue la conciliación (53.1%). En un subanálisis de (n=100) se identificó mala práctica en 43% de casos. Así mismo se identificaron problemas cuyo origen se encuentra en la falta de comunicación o problemas de comunicación en la relación del profesional de la salud bucal � paciente. Conclusiones.- Los factores identificados en las quejas, tales como la falta de comunicación entre el profesional de la salud bucal y el paciente, falsas expectativas de los pacientes y con el incumplimiento de obligaciones, fueron considerados en las Recomendaciones elaboradas