Employing wavelength diversity to improve SOA gain uniformity

In this paper, we propose a wavelength diversity technique for the semiconductor optical amplifier (SOA) to improve the gain uniformity for ultra-high speed optical routers. In such routers, fast SOA gain recovery is required to ensure the minimum gain standard deviation and thus leading to reduction in the system power penalty. The SOA is modeled using a segmentation technique and the detailed theoretical analysis for the model is presented. A direct temporal analysis of the impact of the signal wavelength on the SOA gain is investigated. The SOA gain profile when injected with a burst of input Gaussian pulses for a single wavelength and the proposed wavelength diversity technique are investigated. The operation principle is simulated and the results show a reduction in the gain standard deviation (at 1 mW input power) of 13.1, 11, 8.1, 6.2 and 4.8 dB for the data rates of 10, 20, 40, 80 and 160 Gb/s, respectively

Computational Protein-Ligand Modelling of the Enzymes DNA gyrase and IcaB

Computational modelling of proteins and their interactions with small molecule ligands is a growing field of research. Such studies provide an understanding of how protein structure relates to mechanism and function as well as informing drug discovery and design. This thesis had two main aspects: computational modelling of ciprofloxacin derivatives binding to DNA gyrase and homology modelling of the protein IcaB based on sequence alignment with a related protein, PgaB. The inhibitory activity of synthetic ciprofloxacin derivatives (with various linkage to citrate groups) was experimentally assessed by gel electrophoresis to examine the effect on DNA gyrase binding to a target DNA strand. Overall, the derivative which possessed the greatest inhibition compared to the unmodified ciprofloxacin was the c-gly-ciprofloxacin derivative, which had a 2 atom linker between the ciprofloxacin and citrate groups. This correlated with the change in interactions seen between ciprofloxacin derivatives as computationally modelled by molecular mechanics methods. The second aspect of the thesis was to generate a model of the protein IcaB to test the hypothesis that it is a deactylase of poly-N-acetyl-glucosamine (PNAG) during maturation of the poly-glycan in the extracellular matrix responsible for biofilm generation for bacteria. An initial review of deacetylase enzyme structures identified the conserved features required for activity. A homologous protein, Pga,B was then used as a template to generate a homology model of IcaB. The model maintained the orientation and positioning of the metal-binding and catalytic residues critical for proper deacetylase function. However, the PNAG binding groove, believed to be involved in the transport of the PNAG to the active site of PgaB, was not properly replicated in the IcaB model. Further modelling would require improved characterization of the binding groove of IcaB

Optimisation of the key SOA parameters for amplification and switching

Wireless Sensor Networks (WSN) are composed of small, low cost, resource-constrained computing nodes equipped with low power wireless transceivers. Generally, they are embedded in their environment to perform some specific monitoring and/or control function. Unlike wired networks that have dedicated routers for network connectivity and message forwarding, every node in a WSN can act as a router in a multi-hop network. A WSN can offer a cheap, applicationspecific solution in a variety of situations including military and disaster response scenarios, where other approaches are not viable. Due to their unattended nature and deployment in possibly hostile environmental conditions, there are many challenges in ensuring that a WSN is formed effectively and survives long enough to fulfil its function. Securing a WSN against attack is a particular challenge. Traditional encryption mechanisms are resource hungry and are not sufficient alone to provide a complete solution. This project is concerned with secure routing protocols. Formal methods are used to model and analyse the design of existing protocols and to demonstrate some previously unreported weaknesses

1 x M packet-switched router based on the PPM header address for all-optical WDM networks

This paper presents an all-optical 1xM router architecture for simultaneous multiple-wavelength packet routing, without the need for wavelength conversion. The packet header address is based on the pulse position modulation (PPM) format, which allows the use of only a single-bitwise optical AND gate for fast packet header address correlation. The proposed scheme offers both multicast and broadcast capabilities. We’ve demonstrated a high speed packet routing at 160 Gb/s in simulation, with a low channel crosstalk (CXT) of ~ -27 dB with a channel spacing of > 0.4 THz and a demultiplexer bandwidth of 500 GHz. The output transfer function of the PPM header processing (PPM-HP) module is also investigated in this paper

Impact of signal wavelength on the semiconductor opticalamplifier gain uniformity for high speed optical routers employing the segmentation model

This paper investigates the impact of a train of input Gaussian pulses wavelength on semiconductor optical amplifier (SOA) gain uniformity for high speed applications. In high speed applications, the linear output gain of the input pulses is necessary in order to minimize the gain standard deviation and power penalties. A segmentation model of the SOA is demonstrated to utilize the complete rate equations. The SOA gain profile when injected with a burst of input signal is presented. A direct temporal analysis of the effect of the burst wavelength on the SOA gain and the output gain standard deviation is investigated. The output gain uniformity dependence on the input burst power and wavelength within the C-band spectrum range is analyzed. Results obtained show the proportionality of the peak-gain conditions for the SOA on the nonlinearity of the output gain achieved by the input pulses

The Nature of Monitoring the Constitutionality of Laws and Regulations in the Kingdom of Bahrain

The study aims to explain the reality of control over the constitutionality of laws and regulations in the Kingdom of Bahrain, in terms of the form of this control and the bodies entrusted with moving this control in addition to the effects that result in the two cases of previous and subsequent control over the constitutionality of laws and regulations. It is known that the Bahraini constitutional legislator started with central control. On the constitutionality of laws and regulations in the sense of giving jurisdiction to a single court entrusted with the task of conducting this oversight, and this body was determined by the Bahraini constitutional legislator in accordance with the text of the article of the amended Bahraini constitution of 2002 in the Constitutional Court, and this oversight that the court exercises is not exercised by itself, but rather by His Majesty the King or by The Prime Minister or by the Speaker of the House of Representatives and also the Speaker of the Shura Council as well as the judges of the matter and finally by individuals and these practices of these bodies are in accordance with the terms and conditions established in accordance with the constitution and also in accordance with the law of the court itself in addition to the law of civil and commercial pleadings in a way that does not conflict with the provisions of the law of the court, and these Oversight of these constitutionally defined bodies is optional oversight of constitutionality in accordance with its recognized forms The two are the previous censorship as well as the post censorship, which we will discuss in this study by dividing it into three demands. As for the third requirement, we deal with it the nature of the laws and regulations that are challenged as unconstitutional

Univariate and multivariate analyses of the asset returns using new statistical models and penalized regression techniques

The COVID-19 epidemic has had a profound effect on almost every aspect of daily life, including the financial sector, education, transportation, health care, and so on. Among these sectors, the financial and health sectors are the most affected areas by COVID-19. Modeling and predicting the impact of the COVID-19 epidemic on the financial and health care sectors is particularly important these days. Therefore, this paper has two aims, (i) to introduce a new probability distribution for modeling the financial data set (oil prices data), and (ii) to implement a machine learning approach to predict the oil prices. First, we introduce a new approach for developing new probability distributions for the univariate analysis of the oil price data. The proposed approach is called a new reduced exponential-$X$ (NRE-$X$) family. Based on this approach, two new statistical distributions are introduced for modeling the oil price data and its log returns. Based on certain statistical tools, we observe that the proposed probability distributions are the best competitors for modeling the prices' data sets. Second, we carry out a multivariate analysis while considering some covariates of oil price data. Dual well-known machine learning algorithms, namely, the least absolute shrinkage and absolute deviation (Lasso) and Elastic net (Enet) are utilized to achieve the important features for oil prices based on the best model. The best model is established through forecasting performance

The SCIDOTS Project: Evidence of benefits of an integrated tobacco cessation intervention in tuberculosis care on treatment outcomes

<p>Abstract</p> <p>Background</p> <p>There is substantial evidence to support the association between tuberculosis (TB) and tobacco smoking and that the smoking-related immunological abnormalities in TB are reversible within six weeks of cessation. Therefore, connecting TB and tobacco cessation interventions may produce significant benefits and positively impact TB treatment outcomes. However, no study has extensively documented the evidence of benefits of such integration. SCIDOTS Project is a study from the context of a developing nation aimed to determine this.</p> <p>Methods</p> <p>An integrated TB-tobacco intervention was provided by trained TB directly observed therapy short-course (DOTS) providers at five chest clinics in Malaysia. The study was a prospective non-randomized controlled intervention using quasi-experimental design. Using Transtheoretical Model approach, 120 eligible participants who were current smokers at the time of TB diagnosis were assigned to either of two treatment groups: conventional TB DOTS plus smoking cessation intervention (integrated intervention or SCIDOTS group) or conventional TB DOTS alone (comparison or DOTS group). At baseline, newly diagnosed TB patients considering quitting smoking within the next 30 days were placed in the integrated intervention group, while those who were contemplating quitting were assigned to the comparison group. Eleven sessions of individualized cognitive behavioral therapy with or without nicotine replacement therapy were provided to each participant in the integrated intervention group. The impacts of the novel approach on biochemically validated smoking cessation and TB treatment outcomes were measured periodically as appropriate.</p> <p>Results</p> <p>A linear effect on both 7-day point prevalence abstinence and continuous abstinence was observed over time in the intervention group. At the end of 6 months, patients who received the integrated intervention had significantly higher rate of success in quitting smoking when compared with those who received the conventional TB treatment alone (77.5% vs. 8.7%; p < 0.001). Furthermore, at the end of TB treatment (6 months or later), there were significantly higher rates of treatment default (15.2% vs. 2.5%; p = 0.019) and treatment failure (6.5% vs. 0%; p = 0.019) in the DOTS group than in the SCIDOTS group.</p> <p>Conclusion</p> <p>This study provides evidence that connecting TB-tobacco treatment strategy is significant among TB patients who are smokers. The findings suggest that the integrated approach may be beneficial and confer advantages on short-term outcomes and possibly on future lung health of TB patients who quit smoking. This study may have important implications on health policy and clinical practice related to TB management among tobacco users.</p

Trends in future health financing and coverage: future health spending and universal health coverage in 188 countries, 2016–40

Background: Achieving universal health coverage (UHC) requires health financing systems that provide prepaid pooled resources for key health services without placing undue financial stress on households. Understanding current and future trajectories of health financing is vital for progress towards UHC. We used historical health financing data for 188 countries from 1995 to 2015 to estimate future scenarios of health spending and pooled health spending through to 2040. Methods: We extracted historical data on gross domestic product (GDP) and health spending for 188 countries from 1995 to 2015, and projected annual GDP, development assistance for health, and government, out-of-pocket, and prepaid private health spending from 2015 through to 2040 as a reference scenario. These estimates were generated using an ensemble of models that varied key demographic and socioeconomic determinants. We generated better and worse alternative future scenarios based on the global distribution of historic health spending growth rates. Last, we used stochastic frontier analysis to investigate the association between pooled health resources and UHC index, a measure of a country's UHC service coverage. Finally, we estimated future UHC performance and the number of people covered under the three future scenarios. Findings: In the reference scenario, global health spending was projected to increase from US$10 trillion (95$20 trillion (18 trillion to 22 trillion) in 2040. Per capita health spending was projected to increase fastest in upper-middle-income countries, at 4·2% (3·4–5·1) per year, followed by lower-middle-income countries (4·0%, 3·6–4·5) and low-income countries (2·2%, 1·7–2·8). Despite global growth, per capita health spending was projected to range from only $40 (24–65) to$413 (263–668) in 2040 in low-income countries, and from $140 (90–200) to$1699 (711–3423) in lower-middle-income countries. Globally, the share of health spending covered by pooled resources would range widely, from 19·8% (10·3–38·6) in Nigeria to 97·9% (96·4–98·5) in Seychelles. Historical performance on the UHC index was significantly associated with pooled resources per capita. Across the alternative scenarios, we estimate UHC reaching between 5·1 billion (4·9 billion to 5·3 billion) and 5·6 billion (5·3 billion to 5·8 billion) lives in 2030. Interpretation: We chart future scenarios for health spending and its relationship with UHC. Ensuring that all countries have sustainable pooled health resources is crucial to the achievement of UHC. Funding: The Bill & Melinda Gates Foundation