20 research outputs found

    An Empirical Critique of On-Demand Routing Protocols against Rushing Attack in MANET

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    Over the last decade, researchers had  proposed numerous  mobile ad hoc routing protocols for which are operate in an on-demand way, as standard on-demand routing protocols such as AODV, DSR and TORA, etc., have been shown to often have faster reaction time and  lower overhead than proactive protocols. However, the openness of the routing environment and the absence of centralized system and infrastructure make them exposed to security attacks in large extent.  In particular, one such kind of attacks is rushing attack, which is mostly hard to detect due to their inherited properties, that alters the network statistics radically. In this paper, we modeled a rushing attack which is a powerful attack that exploits the weaknesses of the secure routing protocols. Moreover, to know the weakness and strength of these protocols, it is necessary to test their performance in hostile environments. Subsequently, the performance is measured with the various metrics, some ot them are average throughput, packet delivery ratio, average end-to-end delay and etc., to compare and evaluate their performance

    Designing an Adversarial Model Against Reactive and Proactive Routing Protocols in MANETS: A Comparative Performance Study

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    Mobile ad-hoc networks are self-organized infrastructure less networks that consists of mobile nodes, which are capable of maintaining and forming the network by themselves. Recently, researchers are designed several routing protocols on these networks. However, these routing protocols are more vulnerable to attacks from the intruders, which can easily paralyze the operation of the network due to its inherited characteristics of MANETS. One such type of attack is wormhole attack. Because of its severity, the wormhole attack has attracted a great deal of attention in the research community. This paper compares reactive and proactive routing protocols in adversarial environment. Specifically, wormhole attack is applied to these routing protocols to evaluate its performance through simulation. Comprehensively the results shows the comparative performance of these protocols against wormhole attack is hard to detect and easy to implement

    Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

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    BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

    A new digestion approach for the extraction of microplastics from gastrointestinal tracts (GITs) of the common dolphinfish (Coryphaena hippurus) from the western Mediterranean Sea

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    Plastic ingestion is one of the main impacts of marine litter on organisms. The occurrence of microplastics (MPs < 5 mm) in the stomachs of Mediterranean species was already reported in several studies. In this context, the present study aims to develop a new approach of digestion for the identification of MPs in the gastrointestinal tracts (GITs) of marine organisms. The new approach combines two digestion protocols, including potassium hydroxide (KOH) and nitric acid (HNO3), to remove most organic and inorganic materials. This digestion allows recording small MPs that are difficult to find via routinely stomach content analysis and also to minimize the overestimation of the phenomenon trough the control of airborne contamination. The new approach was tested on a voracious pelagic opportunistic predator, the common dolphinfish, a fishery resource exploited in several Mediterranean areas. The results showed that a large amount of ingested meso- and microplastics, such as fragments or sheets, was recorded in GITs (F = 65.5 %). The FTIR analysis on litter samples allowed to identify polyethylene, polypropylene and polystyrene as dominant constituent polymers of microplastics. These results confirmed that our novel combined digestion protocol represents a reliable approach to detect MPs in opportunistic pelagic predators

    A incubação de ovos e larvas em Genidens genidens (Valenciennes) (Siluriformes, Ariidae) da Baía de Guaratuba, Paraná, Brasil Eggs and larvae mouthbreeding in Genidens genidens (Valenciennes) (Siluriformes, Ariidae) from Guaratuba Bay, Paraná, Brazil

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    <abstract language="eng">At Guaraluba bay, the catfish Genidens genidens shows incubating behavior during the summer months. The larvae are either less or heavier than the eggs, and their stomach analysis confirms the exogenous leeding during incubation. Embryos sizes can increase to 59mm in total lenght and 2,8g in total weight, including the yolksac. It was observed that the largest larvae are guarded by the largest adults, and that the embryo size is similar among individuals from the same adult
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