Typical X-ray Outburst Light Curves of Aql X-1

We show that a typical X-ray outburst light curve of Aql X-1 can be reproduced by accretion onto the neutron star in the frame of the disc instability model without invoking partial accretion or propeller effect. The knee and the subsequent sharp decay in the X-ray light curve can be generated naturally by taking into account the weak dependence of the disc aspect ratio, $h/r$, on the disc mass-flow rate, $\dot{M}_\mathrm{in}$, in the X-ray irradiation flux calculation. This $\dot{M}_\mathrm{in}$ dependence of $h/r$ only slightly modifies the irradiation temperature profile along the hot disc in comparison to that obtained with constant $h/r$. Nevertheless, this small difference has a significant cumulative effect on the hot disc radius leading to a much faster decrease in the size of the hot disc, and thereby to a sharper decay in the X-ray outburst light curve. The same model also produces the long-term evolution of the source consistently with its observed outburst recurrence times and typical light curves of Aql X-1. Our results imply that the source accretes matter from the disc in the quiescent state as well. We also estimate that the dipole moment of the source $\mu \lesssim 2 \times 10^{26}$ G cm$^3$.Comment: 5 pages, 3 figures, submitted to PAS

FINTECH, DIGITALIZATION, AND BLOCKCHAIN IN INSLAMIC FINANCE: RETROSPECTIVE INVESTIGATION

The increasing interest in Fintech, Blockchain, and Digitalization in Islamic Finance created a new area in the literature, requiring a systematic review of these academic publications. The scope of the analysis is limited to journal articles to understand the trends in the indexed journals. Results are categorized into three sections, Islamic banks’ digitalization, Blockchain and Crypto Assets research, and Islamic non-bank financial institutions’ digitalization. Islamic fintech has great potential mainly because of the overlapping norms of Shariah and fintech, making it easier to implement technological disruption into Islamic finance. Moreover, the trust shift to Islamic finance could be merged with the opportunities of fintech and increase the potential of Islamic fintech even more

A Bibliometric Analysis of Fintech and Blockchain in Islamic Finance

This paper conducts a bibliometric research in the literature on Fintech and Islamic finance. The data of this study consists of relevant articles obtained from the Scopus database as of February 2021. A keywords bundle related to Islamic finance and keyword has been used for the search, resulting in 89 publishments included in this research. Results show the stunning increase in the Islamic Fintech publishments after 2017, mainly in the fields of cryptocurrencies, micro-finance, impact investing, and SRI investing, and so on. The two main centers of Islamic Fintech research are Malaysia-Indonesia Region and the GCC area. The increasing number of Islamic Fintech publishments show the potential of the field for the industry's future

Blockchain for a Resilient, Efficient, and Effective Supply Chain, Evidence from Cases

In the modern acquisition, it is unrealistic to consider single entities as producing and delivering a product independently. Acquisitions usually take place through supply networks. Resiliency, efficiency, and effectiveness of supply networks directly contribute to the acquisition system\u27s resiliency, efficiency, and effectiveness. All the involved firms form a part of a supply network essential to producing the product or service. The decision-makers have to look for new methodologies for supply chain management. Blockchain technology introduces new methods of decentralization and delegation of services, which can transform supply chains and result in a more resilient, efficient, and effective supply chain. This research aims to review and analyze the selected current blockchain technology adoptions to enhance the resiliency of supply network management by facilitating collaboration and communication among suppliers and support the decision-making process. In the first part of this study, we discuss the limitations and challenges of the supply chain system that can be addressed by integrating blockchain technology. In the final part, we analyze multiple blockchain-based supply chain use cases to identify how the main features of blockchain are suited best for supply network management

Integration of Blockchain Technology into Supply Network for Resilient and Efficient Acquisition [video]

In the modern acquisition, it is unrealistic to consider single entities as producing and delivering a product independently. Acquisitions usually take place through supply networks. Resiliency, efficiency, and effectiveness of supply networks directly contribute to the acquisition system\u27s resiliency, efficiency, and effectiveness. All the involved firms form a part of a supply network essential to producing the product or service. The decision-makers have to look for new methodologies for supply chain management. Blockchain technology introduces new methods of decentralization and delegation of services, which can transform supply chains and result in a more resilient, efficient, and effective supply chain. This research aims to review and analyze the selected current blockchain technology adoptions to enhance the resiliency of supply network management by facilitating collaboration and communication among suppliers and support the decision-making process. In the first part of this study, we discuss the limitations and challenges of the supply chain system that can be addressed by integrating blockchain technology. In the final part, we analyze multiple blockchain-based supply chain use cases to identify how the main features of blockchain are suited best for supply network management

Is Islamic Finance A Panacea for Global Economic Disruptions After COVID-19

The coronavirus pandemic has led to unprecedented financial and economic disruptions worldwide. Academic interest in the topic of COVID-19 outbreak has led to a rapid influx of publications on the subject matter from both Islamic and conventional finance and economy perspectives. This paper analyses the contributions of Islamic finance and economy (IFE) literature to the global discussion through a bibliometric analysis and literature review of publications on IFE and COVID-19 using the dimensions database. The paper investigates the role IFE research has played in providing solutions capable of addressing global challenges in the wake of the pandemic. The paper reveals that IFE has made efforts during the pandemic to mitigate the effect of the crisis and strengthen economies. But unlike after the 2008 global financial crisis, IFE is not focusing on global solutions and is more confined to localized country-specific solutions for recovery and resilience. The paper recommends repositioning IFE's academic focus towards tackling issues and providing solutions at a global scale

Cybersecurity Acquisition Framework Based on Risk Management: Economics Perspective

Acquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsCyber attacks continuously target organizations, however, the mitigation actions taken for defense are not sufficiently effective. Ability to compute the cost of attacks is crucial to assess the effectiveness of countermeasure investments. In this study, we developed a framework to have a well-informed decision-making process in cybersecurity acquisition by evaluating the business impact caused by the operability losses of assets. We tested the developed framework using various attack and mitigation scenarios. The findings suggest that using a simulation approach to calculate the business impact of cyber attacks provides the ability to support decision-making process.Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited

Octagonal Shaped Metamaterial Absorber Based Energy Harvester

In this study, a novel octagonal shaped metamaterial based broadband absorber is proposed for energy harvesting at WIMAX wireless communication band. The proposal has an absorption of 99.97 % at 5.5 GHz with a bandwidth of 1 GHz between 5 GHz and 6 GHz in Transverse Electric (TE) mode. Transverse Electric (TE), Transverse Magnetic (TM) and Transverse Electromagnetic (TEM) modes are studied numerically in this paper. In TM and TEM modes, proposed structure has absorption of nearly 96 % and 98 % respectively at 6 GHz. The proposed structure is polarization angle independent which is important for energy harvesting applications. Energy harvesting application is realized by using resistive loads on the design, simulations are parametrically studied on resistive loads and experimental study is realized for reflection coefficient measurement and compared with simulated results. Both experimental and simulated results are complying with each other. The proposed structure has different usage areas in stealth areas, detection and imaging. DOI: http://dx.doi.org/10.5755/j01.ms.24.3.18625</p

Family history in stone disease: how important is it for the onset of the disease and the incidence of recurrence?

The aim of this study was to evaluate the possible effect of a positive family history on the age at the onset of urinary stone disease and the frequency of subsequent symptomatic episodes relating to the disease. Between March 2006 and April 2009, patients with either a newly diagnosed or a previously documented stone disease were included in the study program. They were required to fill in a questionnaire and divided into two groups according to the positive family history of stone disease; group I comprised patients with a family history for urinary calculi and group II those without. Depending on the data obtained from questionnaires, all patients were evaluated in detail with respect to the age at the onset of the stone disease, stone passage and interventions over time, time to first recurrence (time interval between the onset of the disease and the first recurrence), number of total stone episodes and recurrence intervals. 1,595 patients suffering from urolithiasis with the mean age of 41.7 (14–69 years) were evaluated with respect to their past history of the disease. There were 437 patients in group I and 1,158 in group II. There was no statistically significant difference between the mean age value of two groups (P = 0.09). When both genders in group I were analyzed separately, female patients tended to have higher rate of family history positivity than males. Comparative evaluation of the age at the onset of the disease between the two groups did reveal that stone formation occured at younger ages in patients with positive family history [P = 0.01 (males), P = 0.01 (females)] and the mean age of onset of the disease was lower in males than females in group I (P = 0.01). Patients in group I had relatively more stone episodes from the onset of the disease [P < 0.01 (2–4 episodes), P < 0.01 (≥5 episodes)]. Male patients were associated with higher number of stone episodes (P = 0.01). Mean time interval between recurrences was noted to be significantly shorter in group I patients when compared with patients in group II [P < 0.01 (males), P = 0.02 (females)]. In conclusion, our results showed that urinary stone formation may occur at younger ages and that the frequency of symptom episodes may be higher in patients with a positive family history. We believe that the positive family history for urinary stone disease could give us valuable information concerning the onset as well as the severity of the disease