Contour: A Practical System for Binary Transparency

Transparency is crucial in security-critical applications that rely on authoritative information, as it provides a robust mechanism for holding these authorities accountable for their actions. A number of solutions have emerged in recent years that provide transparency in the setting of certificate issuance, and Bitcoin provides an example of how to enforce transparency in a financial setting. In this work we shift to a new setting, the distribution of software package binaries, and present a system for so-called "binary transparency." Our solution, Contour, uses proactive methods for providing transparency, privacy, and availability, even in the face of persistent man-in-the-middle attacks. We also demonstrate, via benchmarks and a test deployment for the Debian software repository, that Contour is the only system for binary transparency that satisfies the efficiency and coordination requirements that would make it possible to deploy today.Comment: International Workshop on Cryptocurrencies and Blockchain Technology (CBT), 201

The Impact of Knowledge Creation on Organizational Innovation at Jordanian Medicine Industry

The study aimed to identify the impact of the knowledge creation on organizational innovation at Jordanian pharmaceutical companies, from the perspective of the sample members to the level of adopting knowledge creation modes, and the level of organizational innovation in Jordanian pharmaceutical companies. To achieve the objectives of the study, the researcher developed a questionnaire for the detection of knowledge creation modes (socialization, externalization, combination, and internalization) and the level of organizational innovation. The study sample consisted of (445) employees at Jordanian pharmaceutical companies.  Sample was selected randomly, and in light of this, data was collected and analyzed using the Statistical Package for Social Sciences (SPSS).   The found that the arithmetic mean of the estimates of employees at Jordanian pharmaceutical companies towards knowledge creation modes were high, and the arithmetic mean of the estimates of employees towards organizational innovation were moderate. The results of regression analysis that their is statistically significant effect (α≤0.05) for the knowledge creation on organizational innovation. The results of stepwise multiple also showed that the dimensions of internalization and socialization together   accounted for   (33.2%)   of   the changes in   the dependent   variable (organizational innovation). Keywords: Knowledge management, Knowledge creation, Innovation, Jordanian pharmaceutical companies

Magnetic domain structure in hexagonal crystals

The domains structure of cobalt, gadolinium and terbium have been investigated; single crystals of gadolinium and terbium, were obtained in which the oxide content was considerably reduced by a solid state electrolysis technique. The Bitter technique has been used for most of the observations with a modified colloid, but a dry colloid technique has been used at temperatures below 240 K or higher than room temperature. Two different pieces of apparatus were designed for use at high or low temperatures. In the case of cobalt single crystals the results obtained at room, temperature are similar to those obtained previously. The pattern at 77 K was as expected from the anisotropy data. The lengths of daggers of reverse magnetization and the widths of their bases were found to be in direct proportion (for simple and complex daggers). The variation of the exchange constant A with temperature was also determined. It was not possible to observe a closure domain structure, however this did not rule out the possibility of a partial structure being present on the basal plane, though the variation of dam in width with temperature agrees best with that of Kittel model. The domain, structure of gadolinium was much easier to analyse than that of cobalt. At 274 K patterns on planes containing the c-axis shoved parallel l80 walls, with the development of partial closure structures at the surface near the basal plane and at the oxide inclusions. Basal plane patterns indicate that the l80 vails are not plane and give more detailed information about the mixed nature of the basal structure. The change in domain structure has been studied as the temperature is reduced to 77 K and under the influence of magnetic fields up to l400 Oe. Unexpected results were obtained when the normal field produced by a permanent magnet was applied to the basal plane. Such arrangements produced the well known honeycomb structure which was observed on other materials after an applied field of few K.Oe. was applied parallel or perpendicular to the c-axis. This was believed to be the result of a closure structure with magnetisation laid freely in basal plane. The non-uniformity of' the lines of force produced by such magnet will re-orient the direction of the magnetic moment within the closure region. The domain structure in a cube shaped terbium single crystal was observed at 210 K and different possibilities for the internal configuration were given. Agreement between experimental observation and the proposed model which consists of plate type domains magnetized along the b(_1) and b(_2) axis but not along the third axis b(_3)-axis, which is perpendicular to one surface. The equilibrium, width was measured and compared with the calculated one and they were in. good agreement. The structure at lower temperatures was studied. However as in gadolinium it is still not clear whether the pattern observed at low temperature represents a true domain structure

The Role of Obstetric Ultrasound in the Assessment of Fetal Growth and Development

Diagnostic ultrasound was introduced into obstetrics by Donald in the late 1950's and since that time has played an increasingly important role in the characterisation of normal fetal growth and the detection of intrauterine growth retardation. As a group intrauterine growth retarded fetuses have a high incidence of perinatal mortality and morbidity, and, in the long term, a higher incidence of neurological and intellectual impairment. Therefore, the antenatal detection of this group is desirable to permit careful monitoring and delivery at the optimal time, under the optimal circumstances. The objectives of this thesis were therefore to study the role of obstetric ultrasound in: (1) the determination of birthweight for gestational age growth standards which were displayed for all women with singleton live births, attending The Queen Mother's Hospital (QMH) antenatal clinic from 1985 to 1987; (2) the detection of intrauterine growth retardation (IUGR) by evaluating the effectiveness of seven single ultrasound measurements and two of their combinations . The association of fetal growth retardation with perinatal mortality and congenital malformation was also studied. In pursuit of the first objective a sample of 10259 births occurring in The QMH from 1985 to 1987 were analysed. Tables and curves were provided showing the means, standard deviations and 5th, 10th, 25th, 50th, 75th, 90th and 95th centiles of birthweight by gestational age for each week of gestation from 28 to 42 weeks. Tables and curves were classified according to the sex of the infant and parity of the mother. The sample was composed of singleton live infants born to women who had ultrasound dating of gestation prior to 20 weeks. This sample comprised 26% of all live birth in Greater Glasgow Health Board area and 5. 2% of all live births in Scotland during the study period. Similar analysis was repeated on a subset of 3919 births selected from the above sample. Women included in this group had to meet a number of criteria in order to minimize the effect they might have on the distribution of birthweight for gestational age. These criteria were: (1) their babies were without congenital malformation; (2) spontaneous onset of labour; (3) not on the contraceptive pill for the three months before pregnancy; (4) certain date of last menstrual period; (5) gestational age confirmed by ultrasound prior to 20 weeks. The QMH based standards were then compared with a number of growth standards reported for other populations, including the widely adopted standards of Thomson and associates (1968) for Aberdeen 1948-64 and Forbes and Smalls (1982) for Scotland 1975-79. The QMH based standards were comparable to the previous Scottish standards and slightly higher later in pregnancy. Similarly the 10th centile values were comparable with Scotland 1975-79 (Forbes & Smalls, 1982), but beyond 38 weeks of gestation they were significantly higher. In contrast to previous growth standards, the QMH based standards were obtained from a group of women with accurate ultrasound dating early in pregnancy. These results would justify a further study based on a large population to establish a proper growth standard. Nevertheless, tables and curves will be a useful guide for the birthweigh monitoring of infants born in the QMH. Other variables such as sex of the infant and parity of the mother were also examined in relation to birthweight. Male infants were heavier than females and infants of multiparae were heavier than infants of primiparae. In pursuing the second objective, a total of 14791 consecutive ultrasound measurements of 2810 women with singleton pregnancies, were analysed. All pregnancies were dated before the 20th week by ultrasonic measurements and had a second ultrasonic examination between 28 and 36 weeks of gestation to permit measurements of 7 single measurements and 2 of their combinations to detect those fetuses whose birthweights were below the 10th centile line on the Scottish standards 1975-79 (Forbes & Smalls, 1982). The measurements of biparietal diameter (BPD), head area (HA), head circumference (HC) , abdominal area (AA), abdominal circumference (AC) femur length (FL), amniotic fluid volume (LV), abdominal area x femur length (AAFL) and abdominal circumference x femur length (ACFL) were studied. The measurements below the 10th centile for gestational age were considered abnormal. Fetal head measurements had inferior predictive ability than abdominal measurements. The LV and FL measurements proved to be the least sensitive indicators of IUGR. The combination of FL measurement with that of abdomen had markedly improved the diagnostic accuracy over that of single measurement of FL, AA or AC

Antibacterial and Biocompatible Coating for Cardiovascular Grafts

In chapter 1: Polyethylene terephthalate (PET) is considered as the gold standard cardiovascular graft to restore the function of damaged vessels and heart valves. However, the post implantation complications essentially distract the long-term patency of PET grafts resulting in prolonged hospitalization, graft failure, and patient death. Most of the prominent shortcomings of PET are the substantial thrombogenic property and the associated infections as well as the biocompatibility issues. Therefore, in this thesis, the improvement of the biocompatibility and the infection-resistance properties of PET grafts were our foremost perspective. We fundamentally minimized the bacterial adhesion and enhanced the biocompatibility of woven and knitted forms of crimped PET cardiovascular grafts. Our results proved an effective strategy for graft surface modification in terms of biocompatible and infection-resistant. In chapter 2: the initial bacterial adhesion was minimized by a multifunctional network-structured film coat using a newly synthesized amphiphilic SD-PHA-b-MPEO diblock copolymer. A versatile coating technique was described based on the repulsion forces between the surface and the used polymer to preserve the flexibility and tensile ability of crimped PET grafts. The surface modified graft was confirmed by Fourier transform infrared spectroscopy (FTIR) and by scanning electron microscope (SEM). The employed polymer manifested suitable biocompatibility to host cell as established using mouse L929 fibroblast cell line. Importantly, the negative charge and the hydrophobic properties of the polymer augmented the bactericidal effect of the sulfadimethoxine moiety as reported by the significant bacterial anti-adhesion efficiency for Gram-positive S. aureus and Gram-negative E. coli bacteria, and for the previously vein isolated Gram-positive S. epidermidis. In chapter 3: Unlike previous studies, the bacterial adhesion was enzymatically inhibited using a bacterial lytic enzyme, lysozyme. Accordingly, graft with broad-spectrum bacteria-resistant was developed. The lysozyme enzyme was covalently immobilized on PET graft by end-point method and proved by FTIR and X-ray photoelectron spectroscopy (XPS). The activity of immobilized enzyme against M. lysodeikticus cells displayed a significant reduction as compared to the free enzyme. However, the remaining activity remarkably decreased the adhesion of Gram-positive S. epidermidis and S. aureus bacteria and to less extent of Gram-negative E.coli. The anti-adhesion efficiency showed bacterial cells specificity while, showed no significant effect on L929 cells adhesion and growth. This indicated the utility of the employed strategy to modulate the initial bacteria adhesion to inhibit the graft-associated infection. In chapter 4: FITC-dextran loaded Poly lactic-glycolic acid (PLGA) nanoparticles were covalently immobilized onto two different cardiovascular prostheses namely; woven crimped PET and expanded polytetrafluoroethylene (ePTFE, Teflon®). The grafts surface was modified by introduction of amino groups on the surface. The surface modified graft was characterized by electro kinetic analyzer, and FTIR before the covalent coupling to the carboxyl group of PLGA Nanoparticles was performed. The prepared model manifested homogenous monolayer of nanoparticles on grafts surface and displayed a satisfactory stability under appropriate human-mimic continuous flow conditions for 24h. Additionally, the established biocompatibility of nano-coated grafts highlighted the utility of the immobilized nanoparticles on the graft’s surface as an attractive strategy for local drug delivery to treat the common complications after graft’s implantation, and hence increasing the grafts long-term patency. In chapter 5: A thrombus-resistant graft was developed by covalent immobilization of heparin. Additionally, the host cell compatibility of PET grafts was enhanced by co-immobilization of collagen. Heparin and collagen were immobilized by end-point method into previously functionalized PET grafts and characterized using FTIR and XPS. The modified grafts manifested a significant biological activity in-vitro under human-mimic conditions mainly, substantial resistance of the graft to clot and fibrin formation. Importantly, the co-immobilization of heparin and collagen supported the host cell adhesion and growth, and showed synergistic inhibition effect of platelets deposition after continuous flow for 30 minutes to simulate the massive blood flow conditions. Consequently, this approach minimized the inherent thrombogenicity of the PET grafts and the corresponding host response, hence ensuring a rapid coating of grafts with host cells required for the grafts biocompatibility