671 research outputs found
Side-pumped WGM milled microstub resonator laser
Whispering Gallery Mode (WGM) resonators are promising candidates for realization of ultra-small micro lasers. Conventional 3D resonators such as micro toroids [1], micro spheres [2, 3] and microbottles [4] are well studied as both passive and active devices. The excitation and signal collection are mostly done using evanescently coupled micro-sized fibers [5], integrated waveguides [3] and\or collecting the scattered light [6]. As the spectrum and coupling efficiency highly depend on the excitation position, the coupling system requires precise alignment, and packaging is complex. Here, we demonstrate a completely new micro laser based on WGM generated in an Yb3+-doped stub resonator side-pumped at 976nm wavelength
The Time for a Uniform Fiduciary Duty Is Now
(Excerpt)
The 2008 collapse focused attention on how to better protect investors from securities sellers and advisers who purport to offer unbiased advice, yet do not disclose meaningful conflicts of interest. The push to protect ordinary investors by imposing a uniform fiduciary duty for brokers and investment advisers has gained momentum. This Article examines differences in the standard of care currently owed by financial professionals and the arguments for and against imposing a uniform fiduciary standard
Unwanted Pregnancy and Its Risk Factors Among Pregnant Women in Tehran, Iran
Background: Unwanted pregnancies remain a main public health problem worldwide. In Iran, comparative studies on the risk factors of unwanted pregnancies and their effects on maternal health are rare.
Objectives: This study was conducted to determine the risk factors of unwanted pregnancies and their impact on maternal behavior during pregnancy.
Patients and Methods: This case-control study was carried out on 240 pregnant women who referred to the healthcare centers of Shahid Beheshti University of Medical Science for receiving routine prenatal care. Of the 240 women, 120 had unwanted pregnancies (case) and 120 had wanted pregnancies (control). Data collection was performed using a researcher-made questionnaire. The data were analyzed using chi-square tests, Fisher’s exact tests, t-tests, Mann Whitney U tests, odds ratios, and logistic regression analysis.
Results: Compared to women with wanted pregnancies, those with unwanted pregnancies were more employed (23.3% vs. 12.5%, P = 0.006), had lower education levels (P = 0.016), had lower incomes (P = 0.009), had more children (1.30 ± 1.08 vs. 0.53 ± 0.67, P = 0.001), and had more traditional marriages (15% vs. 3.3%, P = 0.002). Also, women with unwanted pregnancies had significantly lower tendencies to do prenatal care (P = 0.002), had a higher tendency to abortion (P = 0.001), had higher previous abortion attempts (P = 0.001), and had higher levels of unhealthy behaviors (P = 0.017) compared to those with wanted pregnancies.
Conclusions: Lower education and socioeconomic status, longer marriage duration, being employed, and unwilling of spouse were among the risk factors of unwanted pregnancies. These women are at high risk for unhealthy behaviors and have a higher tendency to abortion that consequently threatens their health
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Modeling of eddy current probe response for steam generator tubes
Sample calculations were performed with a three-dimensional (3-D) finite-element model analysis that describe the response of an eddy current (EC) probe to steam generator (SG) tubing artifacts. Such calculations could be very helpful in understanding and interpreting of EC probe response to complex tube/defect geometries associated with the inservice inspection (ISI) of steam generator (SG) tubing. The governing field equations are in terms of coupled magnetic vector and electric scalar potentials in conducting media and of total or reduced scalar potentials in nonconducting regions. To establish the validity of the model, comparisons of the theoretical and experimental responses of an absolute bobbin probe are given for two types of calibration standard defects. Preliminary results are also presented from a recent theoretical study of the effect of ligament size in axial cracks on EC indications with conventional ISI bobbin probes
Estimating flood characteristics using geomorphologic flood index with regards to rainfall intensity-duration-frequency-area curves and CADDIES-2D model in three Iranian basins
This is the final version. Available on open access from MDPI via the DOI in this recordThere is not enough data and computational power for conventional flood mapping methods in many parts of the world, thus fast and low-data-demanding methods are very useful in facing the disaster. This paper presents an innovative procedure for estimating flood extent and depth using only DEM SRTM 30 m and the Geomorphic Flood Index (GFI). The Geomorphologic Flood Assessment (GFA) tool which is the corresponding application of the GFI in QGIS is implemented to achieved the results in three basins in Iran. Moreover, the novel concept of Intensity-Duration-Frequency-Area (IDFA) curves is introduced to modify the GFI model by imposing a constraint on the maximum hydrologically contributing area of a basin. The GFA model implements the linear binary classification algorithm to classify a watershed into flooded and non-flooded areas using an optimized GFI threshold that minimizes the errors with a standard flood map of a small region in the study area. The standard hydraulic model envisaged for this study is the Cellular Automata Dual-DraInagE Simulation (CADDIES) 2D model which employs simple transition rules and a weight-based system rather than complex shallow water equations allowing fast flood modelling for large-scale problems. The results revealed that the floodplains generated by the GFI has a good agreement with the standard maps, especially in the fluvial rivers. However, the performance of the GFI decreases in the less steep and alluvial rivers. With some overestimation, the GFI model is also able to capture the general trend of water depth variations in comparison with the CADDIES-2D flood depth map. The modifications made in the GFI model, to confine the maximum precipitable area through implementing the IDFAs, improved the classification of flooded area and estimation of water depth in all study areas. Finally, the calibrated GFI thresholds were used to achieve the complete 100-year floodplain maps of the study areas.University of BasilicataCNR-IMAAOpenet TechnologiesRoyal Academy of Engineering (RAE
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