Effect of Black hole Attack on Mobile Ad-hoc Networks

Mobile ad hoc networks (MANETs) are obtaining popularity today, as it offers wireless connectivity to the users irrespective of their geographical position. Such networks are composed of a set of stations or nodes that communicating through wireless channels, without any fixed backbone support in which different nodes are allowed to join or leave the network at any time. MANETs are generally more vulnerable to information and physical security threats than wired networks, so security is a vital requirement in MANETs to provide secured communication between mobile nodes. Most of the routing protocols rely on the cooperation among the nodes for secure transmission due to lack of centralized administration. There is no general algorithm for security of principle routing protocols like AODV against various attacks. One of the most common attacks against routing in MANETs is the Black Hole attack. A black hole is a malicious node that uses the routing protocol to advertise itself as having the shortest path to the node whose packets it wants to intercept. In this paper, we examine the effect of blackhole node in adhoc networks using simulator tool NS2

Recurrence of borderline ovarian tumors: a survival analysis

Background: Borderline ovarian tumors are non-invasive tumors that display greater epithelial proliferation and cytological atypia than benign tumors, but less than carcinomas. They may be treated conservatively in young women, however there is a concern for recurrence and progression to frank malignancy. We aimed to study the clinicopathological features of borderline ovarian tumors and their risk of recurrence.Methods: We reviewed the electronic and paper charts of all borderline ovarian tumors operated between January 1, 2001 and December 31, 2019 at a tertiary level teaching hospital in India. Descriptive statistics such as proportions and means were used. A survival analysis was done for recurrence and death.Results: A total of 93 borderline ovarian tumor patients were identified. The most common histology in our study was mucinous 60 (63%) followed by serous 28 (29%). Ninety two (99%) of them were stage I at diagnosis. Microinvasion was present in 27 (26%) of the cases. Out of the 30 fertility sparing operations performed (unilateral salpingo-oophorectomy/cytectomy), 4 (13%) had recurrences and progressed to malignancy. The overall malignancy rate was 4%. There was one mortality secondary to septic shock.Conclusions: Borderline ovarian tumors account for 10-20% of ovarian epithelial tumors and have extremely good prognosis affecting majorly the reproductive aged women. The low recurrence rate and good five year survival rate, at all the stages of the disease enables to incorporate fertility sparing surgeries as part of the staging

Digital Radio over Fiber System with OFDM & OACI Reduction and Its Performance Evaluation

Radio over Fiber (RoF) system uses remodulation technique to reduce the hardware requirement at every Base Station. This paper reports a study of Radio over Fiber system using remodulation along with Digital Modulation scheme of OFDM, in which the same optical carriers are used for both downlink and uplink connection. The main drawback of remodulation ROF system is Optically Generated Adjacent Channel Interference (O-ACI), which is likely to reduce Q-Factor. To overcome this issue, a Single Drive Mach Zehnder Modulator (SD-MZM) is used to tune up the phase and amplitude of carrier signal which can reduce the interference, thereby improving the efficiency level of the system. Instead of a simple Mach Zehnder Modulator used for the conversion of RF signal to Optical signal, a Single Drive Dual Parallel Mach Zehnder Modulator (SD-MZM) at the control station and an MZM modulator at the base station are used. Using a multiuser RoF model, observations are made at various power levels, in terms of Q factor, Eye Height and etc. A Data Envelopment Analysis (DEA) technique is applied to identify the optimum transmission power to achieve high Q factor, eye height and a threshold value of 0.5

Effect of Climatic Variability on the Fishery of Indian Oil Sardine Along Kerala Coast

Indian oil sardine (IOS), the commercially and ecologically important pelagic fish of the Kerala coast is susceptible to climatic variation. The study analyzes the impact of climate change on the catch of Sardinella longiceps along the Kerala coast and tries to predict the catch trend under the two RCP scenarios 4.5 and 6.0 for the period 2020-2100. Monthly catch of IOS by major gears for the period 1990-2016 was collected and Relative effort (Effort) and Weighted CPUE (cpue) were accordingly estimated. The climatic variables Sea Surface Temperature (SST), Precipitation (Pr), Chlorophyll a (SSC) and Salinity (SSS) were obtained from NOAA/NASA. The relationship of cpue and Effort of IOS to environmental variables were explored by Generalized Additive Model. The best fit model was selected using lowest Akaike information criterion (AIC) value, Deviance and F statistic. Predictions of cpue and Effort under RCP 4.5 and RCP 6.0 were done and the catch of IOS was estimated. The GAM model revealed the variations in the catch of IOS in relation to climate change. The SST, SSS and Pr showed a negative relation whereas SSC was found to be positively related to the catch of IOS. The results of the study indicate a decreasing trend of cpue and catch and an increasing trend of Effort towards 2100 under both climate change scenarios

Climate change drivers influencing Indian mackerel fishery in south-eastern Arabian Sea off Kerala, India

The Indian mackerel Rastrelligerkanagurta(Cuvier, 1816) is one of the most important marine fishery resources along the south-eastern Arabian Sea along the coast of Kerala, south India. The effect of selected environmental variables on the Relative effort (Effort) and weighted catch per unit effort (cpue)of the fish were investigated using simple correlation and Path analysis. Six major oceanographic variables, namely sea surface temperature (SST), sea surface chlorophyll-a concentration (SSC), sea surface salinity (SSS), Precipitation (Pr) Indian Ocean Dipole (IOD) and Southern Oscillation Index (SOI) (ENSO index) were selected for the present study. Among these SST had the highest direct negative effect (-0.282, p SSC >SSS

Application of Information Communication Technology in Coastal Resilience through Income Improvement

Application of Information Communication Technology in Coastal Resilience through Income Improvemen

A ring-like accretion structure in M87 connecting its black hole and jet

The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation^{1,2}. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole^3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of 8.4_{-1.1}^{+0.5} Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.Comment: 50 pages, 18 figures, 3 tables, author's version of the paper published in Natur

A ring-like accretion structure in M87 connecting its black hole and jet

The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition\ua0to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow

A Ring-Like Accretion Structure in M87 Connecting Its Black Hole and Jet

The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of 8.4+0.5−1.1 Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow

A network analysis to identify mediators of germline-driven differences in breast cancer prognosis

cited By 0Identifying the underlying genetic drivers of the heritability of breast cancer prognosis remains elusive. We adapt a network-based approach to handle underpowered complex datasets to provide new insights into the potential function of germline variants in breast cancer prognosis. This network-based analysis studies similar to 7.3 million variants in 84,457 breast cancer patients in relation to breast cancer survival and confirms the results on 12,381 independent patients. Aggregating the prognostic effects of genetic variants across multiple genes, we identify four gene modules associated with survival in estrogen receptor (ER)-negative and one in ER-positive disease. The modules show biological enrichment for cancer-related processes such as G-alpha signaling, circadian clock, angiogenesis, and Rho-GTPases in apoptosis.Peer reviewe