Modelling of Ultrafast Waveguided Electro-Absorption Modulator at Telecommunication Wavelength (λ=1.55 μm) based on Intersubband Transition in an InGaAs/AlAs/AlAsSb Asymmetric Coupled Double Quantum Well Lattice-matched to InP

We investigated theoretically a waveguided EAM (Electro-Absorption Modulator) based on ISBT (Intersubband Transitions) in an In(0.53)Ga(0.47)As/AIAs/AIAs(0.56)Sb(0.44) A-CDQWs (Asymmetric Coupled Double Quantum Wells) lattice-matched to InP at telecommunication wavelength (λ=1.55 μm) which offers ultrahigh-speed and moderate voltage swing. Likewise, the temperature dependency in the In(0.53)Ga(0.47)As/AIAs/AIAs(0.56)Sb(0.44) A-CDQWs was investigated at different temperatures from 300 K to 400 K and evidently the InP-based ISB (Intersubband) modulator offers better temperature stability (~ 0.05 nm/C) compared to the InP-based IB (Interband) modulator. The EAM investigated here is anticipated to have a RC-limited speed (f3dB) of. 300 GHz with insertion loss of 5.1 dB, 10 dB extinction ratio and 5.18 dB/V modulation efficiency at a peak-to-peak voltage of 2.0 V which can support a data rate of up to 600 Gbps and beyond

Estimating the avoidable burden of certain modifiable risk factors in osteoporotic hip fracture using Generalized Impact Fraction (GIF) model in Iran

Backgrounds: The number of hip fractures, the most common complication of osteoporosis, has increased rapidly over the past decades. The goal of this study is to estimate the avoidable burden of certain modifiable risk factor of the condition using the Generalized Impact Fraction (GIF) model, which has been suggested and used by epidemiologists to overcome the drawbacks associated with the use of Attributable Fraction index. In addition to preventing a risk factor or the avoidable fraction of burden, this index can also calculate the change in the burden, when a risk factor is altered.Methods: International databases were searched through PubMed, CINAHLD, Embase using OVID and Google scholar. National resources were searched through IranDoc, IranMedex, SID and Journal sites. Other resources include abstract books and articles sent to the IOF congress. The following search strategy was used: (" Osteoporotic fracture" OR " Fragility Hip fracture" OR " Calcium" OR " vitamin D" OR " BMI" OR " lean body weight" OR " Physical activity" OR " exercise" OR " Smoke" ) AND (" prevalence" OR " incidence" OR " relative risk" ) and limited to " humans." Results: With regards to different scenarios already explained in modifying the studied risk factors, the greatest impact in reducing the prevalence of risk factors on osteoporotic hip fractures, was seen in low serum vitamin D levels, low physical activity and low intake of calcium and vitamin D, respectively. According to the fact that interventions for low serum vitamin D and low intake of calcium and vitamin D, are related to each other, it can be concluded that implementing interventions to change these two risk factors, in the easy, moderate and difficult scenarios, would result in approximately a 5%, 11% and 17% decrease in the burden of osteoporotic hip fractures, respectively. The addition of interventions addressing low physical activity in the easy, moderate and difficult scenarios, an 8%, 21% and 35% reduction in the burden of osteoporotic hip fractures would be reported, respectively.Conclusion: Improving serum vitamin D levels, recommending the consumption of calcium and vitamin D supplementations and advocating physical activity are the most effective interventions to reduce the risk of osteoporotic hip fractures. © 2013 Shahnazari et al; licensee BioMed Central Ltd

Can genetic engineering for the poor pay off? : an ex-ante evaluation of Golden Rice in India

Genetic engineering (GE) in agriculture is a controversial topic in science and society at large. While some oppose genetically modified crops as proxy of an agricultural system they consider unsustainable and inequitable, the question remains whether GE can benefit the poor within the existing system and what needs to be done to deliver these benefits? Golden Rice has been genetically engineered to produce provitamin A. The technology is still in the testing phase, but, once released, it is expected to address one consequence of poverty ? vitamin A deficiency (VAD) ? and its health implications. Current interventions to combat VAD rely mainly on pharmaceutical supplementation, which is costly in the long run and only partially successful. We develop a methodology for ex-ante evaluation, taking into account the whole sequence of effects between the cultivation of the crop and its ultimate health impacts. In doing so we build on a comprehensive, nationally representative data set of household food consumption in India. Using a refined disability-adjusted life year (DALY) framework and detailed health data, this study shows for India that under optimistic assumptions this country?s annual burden of VAD of 2.3 million DALYs lost can be reduced by 59.4% hence 1.4 million healthy life years could be saved each year if Golden Rice would be consumed widely. In a low impact scenario, where Golden Rice is consumed less frequently and produces less provitamin A, the burden of VAD could be reduced by 8.8%. However, in both scenarios the cost per DALY saved through Golden Rice (US$ 3.06-19.40) is lower than the cost of current supplementation efforts, and it outperforms international cost-effectiveness thresholds. Golden Rice should therefore be considered seriously as a complementary intervention to fight VAD in rice-eating populations in the medium term

Suppressing Diffusion-Mediated Exciton Annihilation in 2D Semiconductors Using the Dielectric Environment

Atomically thin semiconductors such as monolayer MoS2 and WS2 exhibit nonlinear exciton-exciton annihilation at notably low excitation densities (below ~10 excitons/um2 in MoS2). Here, we show that the density threshold at which annihilation occurs can be tuned by changing the underlying substrate. When the supporting substrate is changed from SiO2 to Al2O3 or SrTiO3, the rate constant for second-order exciton-exciton annihilation, k_XX [cm2/s], is reduced by one or two orders of magnitude, respectively. Using transient photoluminescence microscopy, we measure the effective room-temperature exciton diffusion coefficient in chemical-treated MoS2 to be D = 0.06 +/- 0.01 cm2/s, corresponding to a diffusion length of LD = 350 nm for an exciton lifetime of {\tau} = 20 ns, which is independent of the substrate. These results, together with numerical simulations, suggest that the effective exciton-exciton annihilation radius monotonically decreases with increasing refractive index of the underlying substrate. Exciton-exciton annihilation limits the overall efficiency of 2D semiconductor devices operating at high exciton densities; the ability to tune these interactions via the dielectric environment is an important step toward more efficient optoelectronic technologies featuring atomically thin materials

Blue shifting of the A exciton peak in folded monolayer 1H-MoS2

The large family of layered transition-metal dichalcogenides is widely believed to constitute a second family of two-dimensional (2D) semiconducting materials that can be used to create novel devices that complement those based on graphene. In many cases these materials have shown a transition from an indirect bandgap in the bulk to a direct bandgap in monolayer systems. In this work we experimentally show that folding a 1H molybdenum disulphide (MoS2) layer results in a turbostratic stack with enhanced photoluminescence quantum yield and a significant shift to the blue by 90 meV. This is in contrast to the expected 2H-MoS2 band structure characteristics, which include an indirect gap and quenched photoluminescence. We present a theoretical explanation to the origin of this behavior in terms of exciton screening.Comment: 16 pages, 8 figure

Psychiatric morbidity in married females living away from their spouses attending the psychiatry clinic in a tertiary care, teaching hospital

Background: In India economic problems like dowry and related issues play a major role in the problems of marriage and separation The aim of the present study is to assess the psychological impact on married females who living away from their spouses, and comparison of the psychiatric morbidity with the married women who are living with their spouses.Methods: A total of 35 subjects were included in the study. Intake proforma was specially designed for study and the questions were divided into 4 subscales (somatic complaints anxiety/insomnia social dysfunction and severe depression).Results: The study clearly revealed that the occupational separation has a significant negative impact on the marital quality of the women spouses of men working abroad or living away. Comparison with the marital quality of the control group, the group does not have the separation; the study group differs significantly in marital quality.The factors such as social support from family and friends, the stay of the study group with parents or in-laws, and duration of pre-separation, the study proved that there is no significant difference exists on the marital quality of the study group based on these factors.Conclusions: The numbers of females who were separated from their spouses are more likely to have psychiatric illnesses due the additional work load of looking after the children and managing the household activities. The study also found that the females staying with their parents after the separation from their spouses were less likely to have a severe psychiatric morbidity as they felt comfortable due the cooperation from their parents.

Evaluation of Alternative Intersections and Interchanges: Volume I—Roundabout Capacity and Rollover Analysis for Heavy Vehicles

There is a recent trend of building roundabouts on high-speed roads, often with the considerable presence of heavy vehicles. With the increased presence of trucks on roundabouts, the issue of overturning has become a concern. Although some geometric, vehicle, and loading factors have been connected to rollover, the safety performance of roundabouts built on high-speed roads is not well understood due to their relative novelty. In addition, other concerns related to geometry, driver behavior, and environmental considerations may exist at roundabouts. This study examined roundabout circulatory superelevation, aggressive driver behavior, roundabout readability, and nighttime conditions in the context of heavy vehicle rollover. Moreover, the critical and follow-up headways were estimated for trucks and other vehicles at roundabouts located on the low- and high–speed roads and during daytime and nighttime conditions. This research developed a methodology which may be used to examine truck overturning at roundabouts. A generalized rollover model suitable for application to heavy vehicles was applied to field-observed semi-trailer speeds and paths to estimate their proximity to rollover at newly-built Indiana roundabouts. This was done by introducing delta v - the difference between the critical rollover speed determined from the model and the actual speed. This report revealed that heavy vehicles increased the critical headway, and in turn reduced the entry capacity of roundabouts. Drivers of heavy vehicles, on average, accepted a 1.1 sec longer critical headway than drivers of passenger cars. The effects of nighttime/twilight conditions indicated additional capacity reduction caused by a 0.6 sec longer critical headway compared to daylight conditions. Likewise, drivers on dual-lane roundabouts in rural areas accepted a 0.6 sec longer critical headway than drivers on single-lane roundabouts in urban areas. It was determined that the gap-acceptance parameters for a single-lane roundabout on a low-speed state road were shorter than the national values, resulting on average in 30% higher capacity for Indiana conditions. In contrast, the estimated critical headway was larger for dual-lane roundabouts on high-speed state roads, resulting in 15% reduced capacity for Indiana conditions. The findings of this report are based on low and medium traffic volumes presently observed on high-speed rural and suburban roads. Heavy traffic flow may affect driver behavior; therefore, studying such roundabouts in heavier traffic conditions might improve the results