A survey of nulling pulsars using the Giant Meterwave Radio Telescope

Several pulsars show sudden cessation of pulsed emission, which is known as pulsar nulling. In this paper, the nulling behaviour of 15 pulsars is presented. The nulling fractions of these pulsars, along with the degree of reduction in the pulse energy during the null phase, are reported for these pulsars. A quasi-periodic null-burst pattern is reported for PSR J1738-2330. The distributions of lengths of the null and the burst phases as well as the typical nulling time scales are estimated for eight strong pulsars. The nulling pattern of four pulsars with similar nulling fraction are found to be different from each other, suggesting that the fraction of null pulses does not quantify the nulling behaviour of a pulsar in full detail. Analysis of these distributions also indicate that while the null and the burst pulses occur in groups, the underlying distribution of the interval between a transition from the null to the burst phase and vice verse appears to be similar to that of a stochastic Poisson point process.Comment: 10 pages, 7 figures, accepted for publication in MNRA

Localization Transition of Biased Random Walks on Random Networks

We study random walks on large random graphs that are biased towards a randomly chosen but fixed target node. We show that a critical bias strength b_c exists such that most walks find the target within a finite time when b>b_c. For b<b_c, a finite fraction of walks drifts off to infinity before hitting the target. The phase transition at b=b_c is second order, but finite size behavior is complex and does not obey the usual finite size scaling ansatz. By extending rigorous results for biased walks on Galton-Watson trees, we give the exact analytical value for b_c and verify it by large scale simulations.Comment: 4 pages, includes 4 figure

Analyzing Performance of ZRP by Varying Node Density and Transmission Range

Mobile Ad hoc Network (MANET) is a collection of mobile nodes that are arbitrarily located so that the interconnections between nodes are dynamically changing. In MANET mobile nodes forms a temporary network without the use of any existing network infrastructure or centralized administration. Each node participating in the network acts both as host and a router and must therefore is willing to forward packets for other nodes. For this purpose, a routing protocol is needed. A routing protocol is used to find routes between mobile nodes to facilitate communication within the network. The Zone Routing Protocol (ZRP) is a hybrid routing protocol for MANET which combines the advantages of the proactive and reactive approaches by maintaining an up-to-date topological map of a zone centered on each node. I am going to do simulation based study in order to analyze performance of ZRP protocol and I use Network Simulator (NS-2) tool to analysis performance of ZRP and analysis by varying node density and transmission range on different parameter like throughput, average end to end delay, and Normalized Routing load. Keywords:Routing Protocols, ZRP, Proactive Routing, Reactive Routing, Hybrid Routing

Performance Comparison of TR and FSRUWB System Using Particle Filter: Effects of Frequency, Data Rate, Multi-Path and Multi-Channel Communication

In this study, we introduced a novel scheme based on Transmitted References (TR) and Frequency Shifted Reference (FSR) for ultra-wideband (UWB) system. By taking into account tracking loop-based particle filtering together with a data collecting approach for single and multi-path channel situations, the suggested method is an enhanced model. Each particle's location is determined using this filtering technique, which is then utilised to calculate the timing inaccuracy and regulate the UWB system's timing pulse. Also, it can tackle the multimodal distribution of errors then effectively approximate the optimal solution. The data distribution is discretised via a number of particles that are weighted samples evolving concerning time duration. The simulation results show that, in terms of error rate, number of particles, and delay response, the recommended model of FSR-UWB with particle filter performs better than the TR-UWB with and without considering particle filter

The Public Option: a Non-regulatory Alternative to Network Neutrality

Network neutrality and the role of regulation on the Internet have been heavily debated in recent times. Amongst the various definitions of network neutrality, we focus on the one which prohibits paid prioritization of content and we present an analytical treatment of the topic. We develop a model of the Internet ecosystem in terms of three primary players: consumers, ISPs and content providers. Our analysis looks at this issue from the point of view of the consumer, and we describe the desired state of the system as one which maximizes consumer surplus. By analyzing different scenarios of monopoly and competition, we obtain different conclusions on the desirability of regulation. We also introduce the notion of a Public Option ISP, an ISP that carries traffic in a network neutral manner. Our major findings are (i) in a monopolistic scenario, network neutral regulations benefit consumers; however, the introduction of a Public Option ISP is even better for consumers, as it aligns the interests of the monopolistic ISP with the consumer surplus and (ii) in an oligopolistic situation, the presence of a Public Option ISP is again preferable to network neutral regulations, although the presence of competing price-discriminating ISPs provides the most desirable situation for the consumers

Random sampling vs. exact enumeration of attractors in random Boolean networks

We clarify the effect different sampling methods and weighting schemes have on the statistics of attractors in ensembles of random Boolean networks (RBNs). We directly measure cycle lengths of attractors and sizes of basins of attraction in RBNs using exact enumeration of the state space. In general, the distribution of attractor lengths differs markedly from that obtained by randomly choosing an initial state and following the dynamics to reach an attractor. Our results indicate that the former distribution decays as a power-law with exponent 1 for all connectivities $K>1$ in the infinite system size limit. In contrast, the latter distribution decays as a power law only for K=2. This is because the mean basin size grows linearly with the attractor cycle length for $K>2$, and is statistically independent of the cycle length for K=2. We also find that the histograms of basin sizes are strongly peaked at integer multiples of powers of two for $K<3$

Study on serum iron profile in COVID-19 associated mucormycosis patients

Background: Mucormycosis is an angio-invasive disease caused by fungi prevalence of which in India is approximately 0.14 cases per 1000 population. The incidence of mucor in COVID 19 patients has increased to greater extent. Probable cause of which is increased serum ferritin among these patients and Iron is required by virtually all microbial pathogens for growth and virulence. Hence, we had conducted a study to estimate serum iron profile and association of iron profile with mucor mycosis in covid-19 associated mucormycosis.Methods: Cross sectional study conducted from May 2021 to July 2021 by the department of general medicine, Banglore medical college and research centre, Karnataka. The data collected was analyzed statistically using descriptive statistics.Results: We observed increased prevalence of mucor cases among the patients aged between 41 to 60 years and those who were not vaccinated. Hyperglycaemia had strong correlation with development of mucor. There was lower UIBC, lower TIBC, high ferritin and serum Iron levels among those who had developed mucormycosis.Conclusions: By our observations, we concluded that the increased serum iron, ferritin, transferrin and reduced TIBC and UIBC are the associated risk factor in the development of COVID 19 associated invasive mucor mycosis. Patients with HbA1c >7 are at higher risk of developing COVID 19 associated mucor mycosis