Relaxation to magnetohydrodynamics equilibria via collision brackets

Metriplectic dynamics is applied to compute equilibria of fluid dynamical systems. The result is a relaxation method in which Hamiltonian dynamics (symplectic structure) is combined with dissipative mechanisms (metric structure) that relaxes the system to the desired equilibrium point. The specific metric operator, which is considered in this work, is formally analogous to the Landau collision operator. These ideas are illustrated by means of case studies. The considered physical models are the Euler equations in vorticity form, the Grad-Shafranov equation, and force-free MHD equilibria.Comment: Conference Proceeding (Theory of Fusions Plasmas, 2018), 9 pages, 8 figure

Network Security Devices and Protocols Using State Model Diagrams

Network security is concerned with protecting sensitive information, limiting unauthorised access, and reinforcing network performance. An important factor in network security is encryption. Internet Security Protocol (IPSec) is the de facto open standard for encryption and replaces the older Cisco Encryption Technology (CET). Both encryption protocols are typically implemented and managed using the text based Command Line Interface (CLI). A graphical user interface (GUI) is available; however, it is not routinely used. Regardless of whether the CLI or GUI is used, both encryption suites are complex to implement and manage. State Model Diagrams (SMDs) were developed and successfully used as the pedagogical foundation of internetworking technologies. SMDs integrate pertinent output from devices and protocol finite state information. SMDs are modular and hierarchical models thereby providing top down deconstruction as a cascaded structure. In terms of ease of use, hyperlinks may be used to navigate between different state tables and diagrams. Moreover, as hierarchical model characteristics allow technical detail to be presented and integrated to assist in managing devices. In this paper, SMDs were used to evaluate CET and IPSec via experiments in order to determine their potential value as network management tool

Economic Sustainability of Remote Access Networking Classrooms

Within the higher education domain, there is a prevalent belief that e-learning, virtual classroom and tele-education are essential requirements for the long-term effectiveness and success of educational institutions. Many information technologies have been adopted to assist studying and learning remotely and are hence potentially beneficial to students, teachers and educational providers. For educational providers, the benefits are that there are no physical or geographical limits to the number of students that can be enrolled in a course of study. However, within the field of network technology, students must actually use network devices during their studies. This is important not only because it significantly enhances student learning, but also within this field, employers expect students to have practical ‗hands-on‘ experience. Software simulators are available but they cannot provide students with the necessary practical experience of connecting together the physical devices. Despite the requirements to provide a ‗hands-on\u27 approach it effectively eliminates remote on-line students. Edith Cowan University (ECU) invested over AUD$350,000 in dedicated network teaching laboratories, which are considered to be of a \u27world-class\u27 standard. An access server has been used to provide remote students with access to this equipment. Significantly it is also possible to view the actual network devices by means of a webcam. Whilst remote access to equipment has been possible students only interact via a computer screen. This work allows students to interact by means of Webcam (visual) and Voice over Internet Protocol (VoIP) (audio). Work to date has consisted of establishing the appropriate infrastructure and testing the communication links. Further trials are planned for semester 2, 2008. Traditional remote access can only operate via Command Line Interface (CLI), this can be difficult for many students to practice and gain experience in computer network and internetworking. In effect on-line students will be able to conduct their workshops on a remotely located \u27world class\u27 network laboratory. For students, the on-line curriculum is available twenty four hours a day; there is typically on-line support, and software is now available allowing access to recorded lectures

The relationship between the Wigner-Weyl kinetic formalism and the complex geometrical optics method

The relationship between two different asymptotic techniques developed in order to describe the propagation of waves beyond the standard geometrical optics approximation, namely, the Wigner-Weyl kinetic formalism and the complex geometrical optics method, is addressed. More specifically, a solution of the wave kinetic equation, relevant to the Wigner-Weyl formalism, is obtained which yields the same wavefield intensity as the complex geometrical optics method. Such a relationship is also discussed on the basis of the analytical solution of the wave kinetic equation specific to Gaussian beams of electromagnetic waves propagating in a ``lens-like'' medium for which the complex geometrical optics solution is already available.Comment: Extended version comprising two new section

Cervical spine injury in dismounted improvised explosive device trauma

BACKGROUND: The injury pattern from improvised explosive device (IED) trauma is different if the target is in a vehicle (mounted) or on foot (dismounted). Combat and civilian first response protocols require the placement of a cervical collar on all victims of a blast injury. METHODS: We searched the Joint Theatre Trauma Registry (JTTR) and the Role 3 Hospital, Kandahar Airfield (KAF) database from Mar. 1, 2008, to May 31, 2011. We collected data on cervical fracture; head injury; traumatic amputation; initial blood pressure, pulse, injury severity score (ISS), Glasgow Coma Scale (GCS) score and base excess; and patient demographic information. RESULTS: The concordance rate between JTTR and KAF databases was 98%. Of the 15 693 admissions in JTTR, 326 patients with dismounted IED injuries were located. The rate of cervical collar prehospital placement was 7.6%. Cervical fractures were found in 19 (5.8%) dismounted IED victims, but only 4 (1.2%) were considered radiographically unstable. None of these 19 patients had prehospital placement of a collar. Patients with cervical spine fractures were more severely injured than those without (ISS 18.2 v. 13.4; GCS 10.1 v. 12.5). Patients with head injuries had significantly higher risk of cervical spine injury than those with no head injury recorded (13.6% v. 3.9%). No differences in frequency of cervical spine injury were found between patients who had associated traumatic amputations and those who did not (5.4% v. 6.0%). CONCLUSION: Dismounted IED is a mechanism of injury associated with a low risk for cervical spine trauma. A selective protocol for cervical collar placement on victims of dismounted IED blasts is possible and may be more amenable to combat situations

A comparative study of protoheme and heme d catalases : role of the heme and the heme pocket in catalysis and ligand binding

Catalase dismutes H20 2 to O2 and H20. In successive twoelectron reactions H20 2 induces both oxidation and reduction at the heme group. In the first step the protoheme prosthetic group of beef liver catalase forms compound I, in which the heme has been oxidized from Fe3+ to Fe4+=0 and a porphyrin radical has been created. Compound II is formed by the oneelectron reduction of comp I. It retains Fe4+=0 but lacks the porphyrin radical and is catalytically inert. Molecular structures are available for Escherichia coli Hydroperoxidase II, Micrococcus Iysodeiktus, Penicillium vitale and beef liver enzymes, which contain different hemes and heme pockets. In the present work, the pockets and substrate access channels of protoheme (beef liver & Micrococcus) and heme d (HPII of E. coli and Penicillium) catalases have been analysed using Quanta™ and CharmMTM molecular modeling packages on the Silicon Graphics Iris Indigo 2 computer. Experimental studies have been carried out with two catalases, HPII (and its mutants) and beef liver. Fluoride and formate' are inhibitors of both enzymes, and their binding is modulated by the heme and by distal residues N201 & H128. Both HPII and beef liver enzymes form compound I with H202 or peracetate. The reduction of beef liver enzyme compound I to II and the decay of compound II are accelerated by fluoride. The decay of compound II is also accelerated by formate, and this reagent acts as a 2-electron donor towards compound I of both enzymes. It is concluded that heme d enzymes (Penicillium and HPII of E. coli) are formed by autocatalytic transformation of protoheme in a modified pocket which contains a characteristic serine residue as well as a partially occluded heme channel. They are less active than protoheme enzymes but also do not form the inactive compound II species. Binding of peroxide as well as fluoride and formate is prevented by mutation of H128 and modulated by mutation of N201

The New Insight into the Role of Antimicrobial Proteins-Alarmins in the Immunopathogenesis of Psoriasis

The pathognesis of psoriasis still remains not fully elucidated. Recent advances favor the idea that interactions between innate and adaptive immune response drive inflammatory process in this disease. Innate antimicrobial peptides and proteins (AMPs) are diverse group of small molecules that provide the first line of defense against invading pathogens. In recent years, the novel functions ofAMPs have been identified. There are three subclasses among AMPs that have gained the special interest as a potentially important player in the pathogenesis of psoriasis: cathelicidin, S100 proteins, and defensins. These AMPs have been shown to modulate and trigger host immune response in psoriasis acting as interplayer between innate and adaptive immune mechanisms. Overexpressed in psoriatic lesions, they prime immune cells for enhanced production of proinflammatory mediators and act as chemoattractant for leukocytes. Therefore, the novel term describing AMPs alarmins has been suggested. As multifunctional player in pathogenesis of psoriasis, AMPs may constitute potential target for therapeutic interventions. However, further investigations are required to establish the methods of downregulation of the aberrant proinflammatory functions of AMPs without increasing the risk of infections

Model calculations of the proximity effect in finite multilayers

The proximity-effect theory developed by Takahashi and Tachiki for infinite multilayers is applied to multilayer systems with a finite number of layers in the growth direction. The purpose is to investigate why previous applications to infinite multilayers fail to describe the measured data satisfactorily. Surface superconductivity may appear, depending on the thickness of the covering normal metallic N layers on both the top and the bottom. The parameters used are characteristic for V/Ag and Nb/Pd systems. The nucleation process is studied as a function of the system parameters.Comment: 12 pages, 15 figures, RevTe