Fine-grained reasoning about the security and usability trade-off in modern security tools

Defense techniques detect or prevent attacks based on their ability to model the attacks. A balance between security and usability should always be established in any kind of defense technique. Attacks that exploit the weak points in security tools are very powerful and thus can go undetected. One source of those weak points in security tools comes when security is compromised for usability reasons, where if a security tool completely secures a system against attacks the whole system will not be usable because of the large false alarms or the very restricted policies it will create, or if the security tool decides not to secure a system against certain attacks, those attacks will simply and easily succeed. The key contribution of this dissertation is that it digs deeply into modern security tools and reasons about the inherent security and usability trade-offs based on identifying the low-level, contributing factors to known issues. This is accomplished by implementing full systems and then testing those systems in realistic scenarios. The thesis that this dissertation tests is that we can reason about security and usability trade-offs in fine-grained ways by building and testing full systems. Furthermore, this dissertation provides practical solutions and suggestions to reach a good balance between security and usability. We study two modern security tools, Dynamic Information Flow Tracking (DIFT) and Antivirus (AV) software, for their importance and wide usage. DIFT is a powerful technique that is used in various aspects of security systems. It works by tagging certain inputs and propagating the tags along with the inputs in the target system. However, current DIFT systems do not track implicit information flow because if all DIFT propagation rules are directly applied in a conservative way, the target system will be full of tagged data (a problem called overtagging) and thus useless because the tags tell us very little about the actual information flow of the system. So, current DIFT systems drop some security for usability. In this dissertation, we reason about the sources of the overtagging problem and provide practical ways to deal with it, while previous approaches have focused on abstract descriptions of the main causes of the problem based on limited experiments. The second security tool we consider in this dissertation is antivirus (AV) software. AV is a very important tool that protects systems against worms and viruses by scanning data against a database of signatures. Despite its importance and wide usage, AV has received little attention from the security research community. In this dissertation, we examine the AV internals and reason about the possibility of creating timing channel attacks against AV software. The attacker could infer information about the AV based only on the scanning time the AV spends to scan benign inputs. The other aspect of AV this dissertation explores is the low-level AV performance impact on systems. Even though the performance overhead of AV is a well known issue, the exact reasons behind this overhead are not well-studied. In this dissertation, we design a methodology that utilizes Event Tracing for Windows technology (ETW), a technology that accounts for all OS events, to reason about AV performance impact from the OS point of view. We show that the main performance impact of the AV on a task is the longer waiting time the task spends waiting on events

Development of Empirical Formula for Computing Sediment Loads in Al-Meshkab Regulator Channel

In this research, the sediments' transport and how to compute their amount have been studied in Al-Meshkab regulator channel. Twenty four cross-sections were selected along the reach of Euphrates river to study the characteristics and the rate of transport of sediments. The measured data included: cross-sections of the channel, average velocity, discharge, water surface width, water surface slope, sediment concentration, bed material samples as well as the specific gravity of bed sediments. The length of the study region was 6 km upstream of Al-Meshkab regulator. The study was divided into two parts: the practical part (field and laboratory works) and the statistical part. The research covered the suggestion of an empirical formula which was used to fit the dimensionless form and to predict a relationship between the sediment rate and the different variables. Analysis of Variance (ANOVA) was used to examine the differences between the observed sediment rate and the predicted sediment rate. Results indicated that no statistically significant differences could be detected between observed and computed sediment rate values using the statistical model

Third Order Hamiltonian for a Binary System with Varying Masses Including Preastron Effect

This work concerns of the effects of the variation in the masses for two attracting bodies on the orbiter orbital elements. The formulation of the problem was done in different kind of mechanics, Newtonian, Lagrangian, and Hamiltonian. Moreover, constructing the Hamiltonian function of the varying masses of a binary system including, periastron effect, in canonical form in the extended phase space, up to third order of the small parameter ?, to be able to solve using canonical perturbation techniques. Canonical perturbation method based on Lee transformation was developed by Kamel used to remove the short periodic terms from the Hamiltonian to be able to solve the system of equations. The Hamiltonian of the system was transformed to the extended phase space by introducing two variable represents the variation of the masses and their conjugate momenta. Finally, Hamilton's equation of motions was used to drive general formula to calculate the variations in the elements due to the variations in their masses and what so called periastron effects

Asymptomatic colonization of Staphylococcus aureus with intermediate resistance to vancomycin harboring vanB resistance gene

Objective: Vancomycin has been used worldwide due to empirical therapy against methicillin-resistant Staphylococcus aureus infections. As a result a selective pressure that favors the outgrowth of vancomycin intermediate S. aureus clones will be created. This study was carried out to evaluate vancomycin resistance pattern of S. aureus in Jordan.Methods: A total of 1179 samples, including 566 (48%) from human and 613 (52%) from animals were examined for the presence of S. aureus using standard biochemical tests and polymerase chain reaction (PCR) amplification of coa gene. Resistance to antibiotics was determined by the disk diffusion method. Methicillin resistance strains were tested for vancomycin resistance by minimal inhibitory concentration (MIC), E- test, and the results were confirmed by amplification of van genes, and Pulsed-field gel electrophoresis (PFGE).Results: The prevalence of S. aureus among human source was: 19.35%, 14%, and 8.8% for nasal, nail, and skin, respectively, and for animal sources 27.3%, 5.51%, and 15.86% for milk, nasal, and meat, respectively. Four VISA strains (1.87%) were found to colonize human nares, nails, and skin with vancomycin MIC of 4-8 μg/ml. Van B resistance gene was detected and PFGE with SmaI-digested VISA genomic DNA revealed two different pulsotypes.Conclusion: This is believed to be the first report of VISA strains containing vanB gene isolated from a routine carriage survey. Effective screening directed to persons colonized with VISA should therefore be a priority.Â

Optimum Location and Angle of Inclination of Cut-off to Control Exit Gradient and Uplift Pressure Head under Hydraulic Structures

The work reported in this research presents numerical investigations on the effect of cut-off inclination angle on exit gradient and uplift pressure head under hydraulic structure and determines the optimum location and angle of inclination of cut-off. This problem is solved using the finite element method by using (ANSYS 11.0). It is concluded that using downstream cut-off inclined towards the downstream side with Ө less than 120º is beneficial in increasing the safety factor against the piping phenomenon. The results are evaluated graphically in non-dimensional form

Population pharmacokinetics of vancomycin in Jordanian patients

Purpose: To characterize vancomycin pharmacokinetic properties in a Jordanian population and identify patients’ characteristics that influence vancomycin disposition.Method: A non-linear mixed-effects modeling was applied to evaluate vancomycin population pharmacokinetic parameters in Jordanian patients using NONMEM software. Vancomycin concentrations were obtained retrospectively from patients’ medical records. Demographic, clinical, medication-related, and medical history data were collected and examined as potential predictors of vancomycin disposition.Results: A total of 164 plasma vancomycin measurements from 110 patients, including neonates, older children and adults were collected. Vancomycin pharmacokinetics was described using a onecompartment model. Based on NONMEM objective function value, the selection of other models (e.g., two or three compartments) did not improve the performance of the pharmacokinetic model. Identified predictors of vancomycin clearance include: weight, serum creatinine, chronic renal failure, acute kidney injury and gender. Vancomycin volume of distribution was associated with weight and n-acetylcystine administration.Conclusion: The present analysis is a preliminary step toward developing a vancomycin dosing algorithm in Jordanian population.Keywords: Vancomycin, Population pharmacokinetics, NONME

The influence of anaesthetic drug selection for scoliosis surgery on the management of intraoperative haemodynamic stability and postoperative pain – pharmaceutical care programme

Aim: The aim of this study was to conduct a pharmaceutical care programme for two different anaesthetic methods used during scoliosis surgery, to investigate which method ensured better intraoperative haemodynamic stability and postoperative pain control.Methods: A clinical pharmacist actively participated in a prospective randomised double blind study for 40 patients who had a physical status class I-II ASA, scheduled for scoliosis surgery, who were randomly allocated into two groups, 20 in each group. Both groups received midazolam preoperatively, propofol, sevuflorane, atracurium, and either remifentanil infusion 0.2 &mu;g/kg/min for (Group 1 = G1), or the same dose of remifentanil infusion and low dose ketamine infusion 1 &mu;g/kg/min (Group 2 = G2), antidote medications and postoperative morphine. Patients were subject to a pharmaceutical care programme. Heart rate HR, MAP, vital signs, surgical bleeding, urine output, time to accomplish the wake up test, duration of surgery and duration of anesthesia were recorded. In postanesthesia care unit (PACU) for 24 hours, the recoverytime, the first pain score and analgesic requirements were assessed. All drugs used were documented in medical charts for statistical analysis.Results: Intraoperative heart rate and arterial blood pressure were significantly less (p < 0.05) in G1 as compared with G2. In the (PACU) the first pain score recordings were significantly less (p < 0.05) in G2 than G1. The time which passed until the first patient analgesia demand dose was greater in G2 and morphine consumption was greater in G1 than G2 (p < 0.05). The rest of the results were not significantly different between the two groups. None of the patients had any allergic or adverse drug reaction to any of the medications.Conclusions: Adding a low dose ketamine hydrochloride infusion during scoliosis surgery could be applied as a routine therapy to improve the haemodynamic stability during the surgery and reduce the postoperative morphine consumption. A pharmaceutical care programme tested in this study gave a high score for patient satisfaction.Keywords: scoliosis; remifentanil; ketamin

Effects of maternal age on the expression of mesenchymal stem cell markers in the components of human umbilical cord

Introduction. Although the human umbilical cord (UC) has been previously considered a medical waste, its use as a main source of fetal stem cells for regenerative medicine applications has increased over the past few years. The aim of the study was to assess the impact of the maternal age on the expression of mesenchymal stem cells (MSC) markers CD105 and CD29 in the different areas of human UC. Material and methods. In this comparative cross sectional study, one hundred term UCs from five maternal age groups (20–45 years) were collected after delivery from healthy mothers and were processed to assess both immuno- and gene expression of CD105 and CD29 surface antigen markers using immunohistochemical and RT-PCR techniques. Results. The immunoexpression of CD105 and CD29 in the amniotic membrane (AM) and Wharton’s jelly (WJ), the umbilical artery (UA) and the umbilical vein (UV) showed significant negative correlation with the maternal age (p &lt; 0.001). Reduced amount of cells as well as the studied MSC markers and their gene expression levels were documented in older age mothers. CD105-positive MSCs were more abundant in the UA, whereas CD29-positive MSCs were more abundant in the AM and WJ. Conclusion. The decreased expression of CD105 and CD29 MSCs markers with age suggests that selective isolation of MSCs from Wharton’s jelly, umbilical artery or umbilical vein of younger mothers should be recommended

ESTIMATION OF SLOPE LENGTH FACTOR (L) AND SLOPE STEEPNESS FACTOR (S) OF RUSLE EQUATION IN THE EUPHRATES RIVER WATERSHED BY GIS MODELING

Specific effects of topography over any area watershed erosion are estimated through the LS factor as the product of slope length L and slope steepness factor S using RUSLE equation. The LS factor map of Euphrates watershed was derived from the raw Digital Elevation Model (DEM) by using of ArcMap 10.2 software, the DEM images were provided from United State Geological Survey (USGS) website. The DEM were consisting of sixteen images with cell resolution of 30m*30m, the DEM of Euphrates watershed is ranged from -100 m to 466 m, 98.83% of Euphrates basin area of DEM within the range 0 to 457 m. The slope in percentage rise map of Euphrates watershed is required to estimate the LS factor, the most of slope of this study was ranged from zero to five which represent about 93.12% from total area of basin. The LS factor of Euphrates basin is ranged from (0) to (8010.61), 94.25% of Euphrates watershed area have the LS factor of the range from (0) to (1). Furthermore, the LS factor values more than 500 of watershed have a small area, so the factor value can be considered up to 500 and neglect the other large values of LS factor. The LS values more than 3 were identified the lines of Euphrates river, distributary channel, rills, interrill and gully

Giant Spontaneous Femoral Artery Pseudoaneurysm Treated with Covered Stents : Report of a rare presentation and review of literature

We report the case of a 62-year-old woman who presented with a one-month history of a pulsatile mass, with no antecedent trauma or intervention. Imaging showed a large pseudoaneurysm (PSA) of the distal portion of the left superficial femoral artery. The PSA was treated successfully with endovascular placement of covered stents