Structure and hydration of polyvinylpyrrolidone-hydrogen peroxide

The structure of the commercially important polyvinylpyrrolidone-hydrogen peroxide complex can be understood by reference to the co-crystal structure of a hydrogen peroxide complex and its mixed hydrates of a two-monomer unit model compound, bisVP·2H2O2. The mixed hydrates involve selective water substitution into one of the two independent hydrogen peroxide binding sites

Variations in branching pattern of external carotid artery in a black Kenyan population

Knowledge of variations in branching of external carotid artery is important to minimise inadvertent injury and confusion in identification during neck and craniofacial surgery and interventional neuroradiology. These variations show ethnic differences. Procedures in head and neck are increasing but data on these variations among black populations are scarce. This study therefore examined the branching pattern of external carotid artery in a black Kenyan population. Two hundred and twenty-four common carotid arteries of 112 black adult Kenyans were exposed by cadaveric dissection at Department of Human Anatomy, University of Nairobi, Kenya. The sternocleidomastoid muscle and body of mandible were removed and the external carotid artery and its branches exposed. The conventional pattern of branching was observed in only 41.1% of cases. The variant patterns observed were trifurcation (26.8)%, bifurcation (17.9%) and quadrifurcation (8.9%). There were 20 (5.3%) cases of early division. Linguofacial trunk was observed in 44.7% cases. Frequency of variant branching pattern of external carotid artery in the population studied is high. Interventional radiologists, vascular, craniofacial and neck surgeons should be aware of these. Preoperative sonographic evaluation of the carotid arterial system is recommended.Keywords: External carotid artery, Variation, Trifurcation, Quadrifurcation, Africa

Magneto-transport study of intra- and intergrain transitions in the magnetic superconductors RuSr2GdCu2O8 and RuSr2(Gd1.5Ce0.5)Cu2O10

A characterization of the magnetic superconductors RuSr2GdCu2O8 [Ru-(1212)] and RuSr2(Gd1.5Ce0.5)Cu2O10 [Ru-(1222)] through resistance measurements as a function of temperature and magnetic field is presented. Two peaks in the derivative of the resistive curves are identified as intra- and intergrain superconducting transitions. Strong intragrain granularity effects are observed, and explained by considering the antiphase boundaries between structural domains of coherently rotated RuO6 octahedra as intragrain Josephson-junctions. A different field dependence of the intragrain transition temperature in these compounds was found. For Ru-(1212) it remains unchanged up to 0.1 T, decreasing for higher fields. In Ru-(1222) it smoothly diminishes with the increase in field even for a value as low as 100 Oe. These results are interpreted as a consequence of a spin-flop transition of the Ru moments. The large separation between the RuO2 layers in Ru-(1222) promotes a weak interlayer coupling, leading the magnetic transition to occur at lower fields. The suppression rate of the intragrain transition temperature is about five times higher for Ru-(1222), a result we relate to an enhancement of the 2D character of the vortex structure. A distinctive difference with conventional cuprates is the sharp increase in amplitude of the intergrain peak in both systems, as the field is raised, which is ascribed to percolation through a fraction of high quality intergrain junctions.Comment: Submitted for Physical Review

Point coordination mechanism based mobile ad hoc network investigation against jammers

In this paper, a jamming attack (a kind of Denial-of-Service attack) was investigated, which interfered with the normal operation of a Mobile Ad Hoc network, which is more vulnerable to various attacks because of its self-configuration, dynamic characteristics, therefore, jammers would affect the network QoS parameters by reducing the throughput and increasing the delay. This problem is solved in this study by enabling the Point Coordination Function, which is a media access mechanism specified by the IEEE standard in some selected MANET nodes (guard nodes) to improve the deficiency of MANET’s performance. The Riverbed modeler was utilized as a simulation tool. In this study, six jammers with two different transmission power values had been applied. In a number of different simulation scenarios with and without jammers, the estimated results showed that the jammers affected the network performance by increasing the delay to 3.0658 sec and decreasing the throughput to 120200.59 bits/sec. After enabling the PCF mechanism in a number of selected nodes, the results allowed the user to solve the problem by improving the network deficiency so that the throughput had been increased to 137478.32 bits/sec and the delay had been decreased to 0.7556 sec. It can be concluded that PCF is a good improvement for different levels of jammer transmission power such as 0.01 W and 0.001 W, and PCF also improved the network’s delay and throughput when the number of PCF enabled nodes had been increased to 10 nodes and 12 nodes, respectively. The improvement is also increased. This study can be used in practice for any ad hoc network when attacked by jammer

Impact of Spiritual Well-Being, Spiritual Perspective, and Religiosity on the Self-Rated Health of Jordanian Arab Christians

The purpose of this study was to explore associations of spiritual well-being, spiritual perspective, and religiosity with self-rated health in a convenience sample of 340 adult Jordanian Arab Christians. Data were collected through church and community groups. Results indicated that spiritual well-being and religiosity were positively associated with self-rated health, but in the final regression model only spiritual well-being retained a significant association after controlling for the other spiritual and religious measures. In conclusion, spirituality and religiosity are important to Jordanian Arab Christians’ health and well-being, and the implications for nursing practice are explored

Flow and non-flow event anisotropies at the SPS

A study of differential elliptic event anisotropies (v_2) of charged particles and high-pt pions in 158 AGeV/c Pb+Au collisions is presented. Results from correlations with respect to the event plane and from two-particle azimuthal correlations are compared. The latter give systematically higher v_2 values at pt>1.2GeV/c providing possibly an evidence of a non-flow semihard component.Comment: 4 pages, 6 figures, Quark Matter 2002, Nantes, to appear in Nucl. Phys.

Event-by-event fluctuations of the mean transverse momentum in 40, 80, and 158 A GeV/c Pb-Au collisions

Measurements of event-by-event fluctuations of the mean transverse momentum in Pb-Au collisions at 40, 80, and 158 A GeV/c are presented. A significant excess of mean p_T fluctuations at mid-rapidity is observed over the expectation from statistically independent particle emission. The results are somewhat smaller than recent measurements at RHIC. A possible non-monotonic behaviour of the mean p_T fluctuations as function of collision energy, which may have indicated that the system has passed the critical point of the QCD phase diagram in the range of mu_B under investigation, has not been observed. The centrality dependence of mean p_T fluctuations in Pb-Au is consistent with an extrapolation from pp collisions assuming that the non-statistical fluctuations scale with multiplicity. The results are compared to calculations by the RQMD and UrQMD event generators.Comment: 28 pages, 10 figure

Spatial and seasonal ionospheric error growth in DGPS measurement: a case study in Malaysia

This paper tackles the Equatorial ionosphere and its effects on Differential Global Positioning System (DGPS) error growth over Malaysia by using a network of GPS Continuously Operating Reference Stations (CORS). Seasonal variation of ionospheric delay has been examined and findings show that the effect of spatial variation of ionospheric errors in DGPS is very significant during the equinoctial seasons. Furthermore, a DGPS regression model was developed and tested during the solar maximum year in 2013 by using internet-based DGPS. The results show that the model is capable of estimating DGPS positional errors for distances of user to reference station less than 680 km