ABSTRACT
Soft X-ray emission (0.5–2.0 keV) plays a pivotal role in regulating the optical and ultraviolet (UV) emission in the active galactic nuclei (AGNs). We collected a sample of 1811 AGNs from ...the SDSS database and obtained various parameters of Balmer lines, optical continuum, Mg ii line & UV continuum and studied their dependencies on soft X-ray luminosity. Based on the linear regression analysis, we found that FWHM$_{\rm {Mg\,\,\small {II}}}$ ∝ FWHM$_{\text{H}\beta }^{0.554}$ suggesting that UV emission is arising from a region relatively outside the broad-line region (BLR) associated to the Hβ emission and found a strong correlation between optical and UV luminosities (L$_{\rm {Mg\,\,\small {II}}}$ ∝ $L_{\rm {H}\beta }^{0.822}$). It was noticed that the dependency of optical continuum luminosities on soft excess changes with the redshift (LX ∝ L$^{0.596}_{5100\, \mathring{\rm A}}$ for z < 0.5 and LX ∝ L$^{0.429}_{5100\, \mathring{\rm A}}$ for z > 0.5). The full width at half-maximum components of Hβ and Mg ii core components were found to be virialized and is not affected by the soft excess emission whereas the wings of Mg ii display a dependency. We estimated a relation viz. LX ∝L$^{0.520}_{3000\, \mathring{\rm A}}$ FWHM$^{0.525}_{\rm {Mg\,\,\small {II}}}$ and found to be well in agreement with a proposed physical scenario. All the derived relations were used to understand the intermodulating association of the BLR and disc in the AGNs.
ABSTRACT
Understanding the radiative and physical structures of inner region of a few 100 pc of active galactic nucleus (AGNs) is important to constrain the causes of their activities. Although the ...X-ray emission from the Comptonization region/corona and the accretion disc regulates the broad-line emission regions and torus structures, the exact mutual dependency is not understood well. We performed correlation studies for X-ray, mid-infrared, and different components of Balmer emission lines for the selected sample of AGNs. Almost 10 different parameters and their interdependencies were explored in order to understand the underlying astrophysics. We found that the X-ray luminosity has a linear dependency on the various components of broad Balmer emission lines (e.g. L$_{\text{2-10 keV}}\, \propto$ L$^{0.78}_{\text{H}\beta ^{\text{B}}}$) and found a strong dependency on the optical continuum luminosity (L$_{\text{2-10 keV}}\, \propto$ L$^{0.86}_{5100\, \mathring{\rm A}}$). For a selected sample, we also observed a linear dependency between X-ray and mid-infrared luminosity (L$_{\text{2-10 keV}}\, \propto$ L$^{0.74}_{6\, \mu \text{m}}$). A break point was observed in our correlation studies for X-ray power-law index, Γ, and mass of black hole at ∼ log (M/M⊙) = 8.95. Similarly, the relations between Γ and full width at half-maximum (FWHM) of H α and H β broad components show breaks at FWHMH α = 7642 ± 657 km s−1 and FWHMH β = 7336 ± 650 km s−1. However, more data are required to confine the breaks locations exactly. We noted that Γ and Eddington ratios are negatively correlated to Balmer decrements in our selected sample. We analysed and discussed about the implications of new findings in terms of interaction AGN structures.
The future wireless Fifth Generation (5G) communication network required a higher bandwidth in order to achieve greater data rate. It will be largely characterized by small cell deployments, ...typically in the range of 200 meters of radius/cell, at most. The implementation of small size networks delivers various advantages such as high data rate and low signal delay. However, it also suffers from various issues such as inter-cell, intra-cell, and inter-user interferences. This paper discusses the issues related to interference management for 5G network from the perspective of Heterogeneous Network and Device-to-Device communication, by using enabling techniques, such as Inter-cell Interference Coordination, Coordinated Multipoint, and Coordinated Scheduling. Furthermore, several pertinent issues have been critically reviewed focusing on their methodologies, advantages and limitations along with the future work. Future directions proposed by the 3rd Generation Partnership Project for interference mitigation has also been outlined. This review will act as a guide for the researchers to comprehend various existing and emerging enabling interference mitigation techniques for further exploration and smooth implementation of 5G wireless network.
In order to mitigate the power consumption issue for the sensor’s nodes, an efficient power optimized routing protocol is needed. Therefore, this paper proposes a network coding backpressure routing ...(NCBPR) routing scheme for a large-scale Internet of Things (IoT) networks, which exploits the backpressure algorithm in order to divert packets flow. In the network, the packets are flowing from the highly congested node to low congested node, which helps to balance the load and optimized the fair use of the battery power of all the participating nodes. It divides the network into the small clusters, where the selection of clusters head depends upon an additional parameter of battery power apart from other optimum path parameters. It also employs an efficient data aggregation mechanism, which improves the throughput of the network by eliminating redundant packets. The network has been designed by considering 300 nodes in a network and the results have been drawn in terms of network throughput, packet delivery ratio and energy consumption. The results are presented in comparison with conventional well-known information-fusion-based role assignment (InFRA) and data routing for in-network aggregation (DRINA) routing schemes. The results prove that the proposed NCBPR scheme delivers significant improvement, such as throughput which increased by 21.38 and 12.13%, packet delivery ratio improved by 24.73 and 11.38%, and sensors node’s energy consumption is decreased by 61.46 and 44.35% as compared to conventional InFRA and DRINA schemes, respectively.
Routing is fundamental in any wireless network for path selection, which provides the most effective way that legitimizes the data to be transmitted from a source to a destination device. In gigantic ...network demand nowadays, routing is pertinent to ensure fast and reliable data transfer. Ineffective routing may cause route flapping and degrade the overall Quality of Service (QoS). Meanwhile, Device-to-Device communications (D2D) is a technology that allows the devices to be connected without or partial involvement of the conventional cellular network. With these natures of qualities, D2D communication provides a reliable propitious medium that caters for the needs of many different telecommunications scenarios. The interconnectivity of multiple devices creates the Internet of Things (IoT), which will be an essential insistent in future technologies. With the dynamic nature of D2D technology, the routing approach act as a principal architecture that essential to be implemented in every niche D2D aspect. If wrong routing decisions are made in D2D communication, the QoS performance would be worse than the conventional cellular network. This paper present the state of the art of fundamentals, recent progress, current challenges, future directions, and potential routing applications for D2D and Beyond IoT 5G Networks. This review will also act as a guide and reference for future researchers and scientists to explore and integrate the routing technique in D2D communication and Beyond IoT 5G Networks.
Point-of-care ultrasound (PoCUS) is used by health care professionals of various specialties worldwide, with excellent results demonstrating significant potential to advance patient care. However, in ...low resource areas of the world, where other imaging modalities are scarce and the potential of handheld pocket-sized PoCUS devices with great versatility and increasing affordability seems most significant, its use is far from being widespread. In this report, our group of Chadian, Israeli, and Canadian physicians with experience in rural, military, and conflict zone medical aid, discusses the barriers to the implementation of PoCUS in low resource areas and offers potential solutions.
In this paper, we propose a data aggregation back pressure routing (DABPR) scheme, which aims to simultaneously aggregate overlapping routes for efficient data transmission and prolong the lifetime ...of the network. The DABPR routing algorithm is structured into five phases in which event data is sent from the event areas to the sink nodes. These include cluster-head selection, maximization of event detection reliability, data aggregation, scheduling, and route selection with multi attributes decision making metrics phases. The scheme performs data aggregation on redundant data at relay nodes in order to decrease both the size and rate of message exchanges to minimize communication overhead and energy consumption. The proposed scheme is assessed in terms of packet delivery, network lifetime, ratio, energy consumption, and throughput, and compared with two other well-known protocols, namely “information-fusion-based role assignment (InFRA)” and “data routing for in-network aggregation (DRINA)”, which intrinsically are cluster and tree-based routing schemes designed to improve data aggregation efficiency by maximizing the overlapping routes. Meticulous analysis of the simulated data showed that DABPR achieved overall superior proficiency and more reliable performance in all the evaluated performance metrics, above the others. The proposed DABPR routing scheme outperformed its counterparts in the average energy consumption metric by 64.78% and 51.41%, packet delivery ratio by 28.76% and 16.89% and network lifetime by 42.72% and 20.76% compared with InFRA and DRINA, respectively.
The concept of the Internet of Things (IoT)-based Wireless Sensor Network (WSN) is rapidly gaining wide-spread recognition and acceptance in our day-to-day lives. Nowadays, the application of the IoT ...sensor nodes in various domains of endeavors such as health-care, smart homes, industrial and production sectors, control networks, and in many other fields has continued to increase steadily. In IoT-based WSN, sensor nodes dynamically join the internet and collaborate to accomplish a mission by sensing and collecting event data from the application field. The sensor nodes thus forward the collected information to the sink nodes or to the nearest base station for further transmission. However, one of the significant drawbacks of the IoT-based WSN networks is that the battery life of the sensor nodes is often short-lived due to the energy-limited nature of the electronic sensors, resulting in the network’s short lifetime. Thus, prolonging the lifetime duration of the sensor nodes becomes a fundamental task. Whether the battery life of a sensor node is extended for a reasonable length of time or depleted in a moment depends mainly on the energy efficiency of the underlying routing protocol. Therefore, the issue of network lifetime can be fundamentally addressed by implementing an efficient and robust energy-aware routing protocol for sustainable and prolonged network operation time in a WSN based IoT network scenario. In this paper, a cluster-based Backpressure routing (CBPR) scheme has been proposed, which targets to prolong the network lifetime and enhance the data transmission reliability using energy load-balancing mechanism. For every cluster of the sensor node, the CBPR scheme elects a cluster head which has the highest energy level and the shortest distance to the sink node. The proposed CBPR routing scheme further utilizes a very robust data aggregation algorithm to checkmate and prevent the circulation of redundant data packets in the network while also exploiting the Backpressure scheduling machine for data packets queueing and for route selection, which allows it to select the next-hop sensor node based on the queue length value of the sensor nodes. Extensive simulations have been performed to evaluate the efficiency of the proposed CBPR routing scheme, which was compared with that of other well-known routing schemes such as the Information Fusion Based Role Assignment and Data Routing for In-Network Aggregation in terms of throughput, energy consumption, and packet delivery ratio.
The surge in global population is compelling a shift toward smart agriculture practices. This coupled with the diminishing natural resources, limited availability of arable land, increase in ...unpredictable weather conditions makes food security a major concern for most countries. As a result, the use of Internet of Things (IoT) and data analytics (DA) are employed to enhance the operational efficiency and productivity in the agriculture sector. There is a paradigm shift from use of wireless sensor network (WSN) as a major driver of smart agriculture to the use of IoT and DA. The IoT integrates several existing technologies, such as WSN, radio frequency identification, cloud computing, middleware systems, and end-user applications. In this paper, several benefits and challenges of IoT have been identified. We present the IoT ecosystem and how the combination of IoT and DA is enabling smart agriculture. Furthermore, we provide future trends and opportunities which are categorized into technological innovations, application scenarios, business, and marketability.
The association between diabetes mellitus and tuberculosis is a health-threatening double trouble. Vulnerable populations such as refugees and conflict-displaced populations may be at higher risk of ...both diseases. Here, we examined the prevalence of latent tuberculosis infection (LTBI) and its associated risk factors in a population of Syrian refugees with diabetes in North Lebanon.
This is a cross-sectional study.
A total of 87 Syrian refugees with diabetes were enrolled. Demographic and clinical data were collected using a structured questionnaire, and a blood sample was obtained from each patient. LTBI was examined using the last generation QuantiFERON-TB Gold Plus assay.
The mean age of the study population was 54.1 ± 10.5 years, and the majority were women (79.3%). LTBI was found in 1 in 5 (17/87; 19.5%) enrolled patients, with the majority being originated from Aleppo (47.05%). Infection was significantly associated only with age (P = 0.009), and its risk was 4-fold higher in patients aged ≥60 years (odds ratio: 4.1, confidence interval: 1.4–12.5, P = 0.018).
This study highlights the need to implement effective tuberculosis control strategies among refugees with diabetes, with particular attention to those at older age.
•Prevalence of latent tuberculosis among Syrian refugees with diabetes never investigated.•One of 5 Syrian refugees with diabetes in Lebanon has a latent tuberculosis infection.•Older age is significantly associated with tuberculosis infection in this population.•TB control measures should be implemented among refugees with diabetes, esp. elders.•Diabetes-TB requires intl. efforts & resource mobilization in humanitarian settings.
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