699 research outputs found

    A Study on Hierarchical Model of a Computer Worm Defense System

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    This research addresses the problem of computer worms in the modern Internet. A worm is similar to a virus. A worm is a self-propagating computer program that is being increasingly and widely used to attack the Internet. It is considered as a sub-class of a virus because it is also capable of spreading from one computer to another. Worms are also computer programs that are capable of replicating copies of themselves via network connections. What makes it different however is that unlike a computer virus a computer worm can run itself without any human intervention? Because of these two qualities of a worm, it is possible that there will be thousands of worms in a computer even if only one computer worm is transferred. For instance, the worm may send a copy of itself to every person listed in the e-mail address book. The worm sent may then send a copy of itself to every person who is listed in the address book of the person who receives the email. Because this may go on ad infinitum worms can not only cause damage to a single computer and to other persons computer but it can only affect the functionality of Web servers and network servers to the point that they can no longer function efficiently. One example is the .blaster worm

    Engineering Performance of a New Siloxane-Based Corrosion Inhibitor

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    This paper presents an evaluation of a new non-toxic corrosion inhibitor on selected engineering properties of concrete mixes with different cementitious materials following a corrosion and durability study on concrete samples. Corrosion inhibitors consist of powders or solutions which are added to concrete when mixed to prevent or delay corrosion of steel by their reaction with ferrous ions to form a stable and passive ferric oxide film on the steel surface. The new inhibitor functions slightly differently and its corrosion inhibition effect is due to the formation of a siloxane coating on the steel surface. Therefore, the performance of the new inhibitor in concrete mixes manufactured with CEM I, PFA and GGBS cements was compared against a well known and established corrosion inhibitor on the market, namely calcium nitrite in terms of their effect on workability (measured in terms of slump), compressive strength, freeze–thaw durability and macro-cell corrosion. The results from this experimental programme have demonstrated that the new inhibitor is effective in reducing or slowing down corrosion. In addition, it was found that CEM I concrete containing the new inhibitor was less penetrable to chlorides than that without. A similar set of results was obtained for the freeze– thaw resistance, but the compressive strength was found to decrease with the addition of the new inhibitor. In the case of concretes containing PFA and GGBS, the new inhibitor was found to be less effective. Further, long-term investigations are recommended to assess the effectiveness over time

    Functional analysis of cemented bipolar hemiarthroplasty with medial calcar augmentation for unstable intertrochanteric fractures in elderly

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    Background: Intertrochanteric fracture is one of the most common fractures among the elderly osteoporotic population, constituting about 50% of hip fractures. These fractures are managed either by fixation using dynamic hip screw (DHS), proximal femur nail (PFN) or by replacement, based on the stability of fracture pattern, age of the patient, quality of bone and associated co-morbid conditions. Prosthetic replacement which is routinely done for femoral neck fractures requires modification when done for trochanteric fractures to improve stability. This study aims to analyse the short term functional outcome of cemented bipolar hemiarthroplasty with medial calcar augmentation for unstable intertrochanteric fractures in elderly.Methods: Our study includes 60 patients of age more than 70 years admitted in our institution during June 2012 to September 2016 with unstable intertrochanteric fractures. All patients operated through posterior approach to hip and cemented hemiarthroplasty with medial calcar augmentation with bone graft was done. Patients were followed up for an average of period of 2 years. Functional outcome was evaluated with Harris Hip score.Results: 28% of cases had excellent outcome. 43% of cases had good and 23% of cases had fair outcome. 2% of cases ended with poor outcome. The in-hospital mortality rate was 3.3%. The survival rate of the patients in this study at the end of one year is 85%. Conclusions: Cemented bipolar hemiarthroplasty with medial calcar augumentation can be considered as a good primary option for elderly unstable intertrochanteric fracture patients with osteoporotic bones and associated co-morbidities. 

    Adaption of Wheat Genotypes to Drought Stress

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    Drought can serve to restrict the growth and development of wheat. The current research was conducted to screen for drought-tolerant wheat genotypes through phenotypic markers, including growth indicators and yield. We used a Randomized Complete Block (RCB) design with three replicate sites (about333 m2 area per replicate). Six wheat genotypes which are frequently grown under rain-fed conditions at the southern highland of West-Bank, Palestine were evaluated for specific phenotypes including stem length, spike with awns length, awns length, number of tillers, total grain, total hay, and mass of seeds (per 100). The results showed significant variations among the six wheat genotypes for most of the measured parameters. Yellow-Hetia genotype showed the highest stem length, spike with awns length, awns length, weight of 100 seeds, and yield (grain plus hay). However, the remaining genotypes presented almost similar production ranging from 475-488 kg/dunum. In contrary, Nab-El-Jamal genotype exhibited the lowest grain production and Um-El-Rabee' genotype revealed the minimum hay production. Based on our data, Yellow-Hetia could be a promising cultivar for future breeding programs, especially those involving drought tolerance

    Fifteen new records of Batoids (Elasmobranchii) from waters off Andaman and Nicobar Islands, India

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    Marine waters of Andaman and Nicobar Islands, India in the tropical Indian Ocean, is a poorly explored high faunal diverse region. The present study documents new records of batoids from the region, identified during the fishery and diversity monitoring surveys conducted during November 2016 to June 2019 at different fish landing centers of Andaman and Nicobar Islands. Fifteen elasmobranch species including 2 wedgefishes, 1 skate and 12 rays were identified and confirmed as new reports for the region. Results of this study indicate that the elasmobranch diversity, especially batoid diversity of Andaman and Nicobar Islands are poorly documented and future systematic surveys including that of deeper reef habitat may help to explore the diversity in the region

    Microcalcifications Detection using PFCM and ANN

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    This work presents a method to detect Microcalcifications in Regions of Interest from digitized mammograms. The method is based mainly on the combination of Image Processing, Pattern Recognition and Artificial Intelligence. The Top-Hat transform is a technique based on mathematical morphology operations that, in this work is used to perform contrast enhancement of microcalcifications in the region of interest. In order to find more or less homogeneous regions in the image, we apply a novel image sub-segmentation technique based on Possibilistic Fuzzy c-Means clustering algorithm. From the original region of interest we extract two window-based features, Mean and Deviation Standard, which will be used in a classifier based on a Artificial Neural Network in order to identify microcalcifications. Our results show that the proposed method is a good alternative in the stage of microcalcifications detection, because this stage is an important part of the early Breast Cancer detectio

    Sleep-wake sensitive mechanisms of adenosine release in the basal forebrain of rodents : an in vitro study

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    Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB) to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS) inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state

    ELECTROCHEMICAL REDUCTION OF CARBONYL COMPOUNDS

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    Cyclic voltammograms were taken for aromatic carbonyl compounds like benzaldehyde and acetophenone in 0.2M sulphuric acid medium and Mcilvaine buffer at lead electrodes. Galvanostatic reduction of both aliphatic and aromatic carbonyl compdunds was carried out at tin and zinc electrodes in alkaline and acid medium, to obtain corresponding pinacols and alcohols
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