1,217 research outputs found
Non-Symbolic Fragmentation
This paper reports on the use of non-symbolic fragmentation of data for securing communications. Non-symbolic fragmentation, or NSF, relies on breaking up data into non-symbolic fragments, which are (usually irregularly-sized) chunks whose boundaries do not necessarily coincide with the boundaries of the symbols making up the data. For example, ASCII data is broken up into fragments which may include 8-bit fragments but also include many other sized fragments. Fragments are then separated with a form of path diversity. The secrecy of the transmission relies on the secrecy of one or more of a number of things: the ordering of the fragments, the sizes of the fragments, and the use of path diversity. Once NSF is in place, it can help secure many forms of communication, and is useful for exchanging sensitive information, and for commercial transactions. A sample implementation is described with an evaluation of the technology
A contribution to the study of arterio-sclerosis
The Pathological condition Arterio-sclerosis has been variously described by different Authors.
Savill, in opening a discussion on Arterio- sclerosis before the Pathological Society of London. (Feb: l6. 1904.), said that he was accustomed to define Arterio- sclerosis as a chronic generalised thickening, condensation, or degeneration of the Arterial walls, in which after death, the lumen does not collapse as usual, and the walls are harder and less elastic than normal.
Histologically, such a condition may occur in three situations, -in the Tunica media, when it is medial sclerosis, -in the Tunica intima, i.e. Intimal sclerosis, and in the Tunica adventitia, i.e. adventitial sclerosis
Submillimeter diffusion tensor imaging and late gadolinium enhancement cardiovascular magnetic resonance of chronic myocardial infarction.
BackgroundKnowledge of the three-dimensional (3D) infarct structure and fiber orientation remodeling is essential for complete understanding of infarct pathophysiology and post-infarction electromechanical functioning of the heart. Accurate imaging of infarct microstructure necessitates imaging techniques that produce high image spatial resolution and high signal-to-noise ratio (SNR). The aim of this study is to provide detailed reconstruction of 3D chronic infarcts in order to characterize the infarct microstructural remodeling in porcine and human hearts.MethodsWe employed a customized diffusion tensor imaging (DTI) technique in conjunction with late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) on a 3T clinical scanner to image, at submillimeter resolution, myofiber orientation and scar structure in eight chronically infarcted porcine hearts ex vivo. Systematic quantification of local microstructure was performed and the chronic infarct remodeling was characterized at different levels of wall thickness and scar transmurality. Further, a human heart with myocardial infarction was imaged using the same DTI sequence.ResultsThe SNR of non-diffusion-weighted images was >100 in the infarcted and control hearts. Mean diffusivity and fractional anisotropy (FA) demonstrated a 43% increase, and a 35% decrease respectively, inside the scar tissue. Despite this, the majority of the scar showed anisotropic structure with FA higher than an isotropic liquid. The analysis revealed that the primary eigenvector orientation at the infarcted wall on average followed the pattern of original fiber orientation (imbrication angle mean: 1.96 ± 11.03° vs. 0.84 ± 1.47°, p = 0.61, and inclination angle range: 111.0 ± 10.7° vs. 112.5 ± 6.8°, p = 0.61, infarcted/control wall), but at a higher transmural gradient of inclination angle that increased with scar transmurality (r = 0.36) and the inverse of wall thickness (r = 0.59). Further, the infarcted wall exhibited a significant increase in both the proportion of left-handed epicardial eigenvectors, and in the angle incoherency. The infarcted human heart demonstrated preservation of primary eigenvector orientation at the thinned region of infarct, consistent with the findings in the porcine hearts.ConclusionsThe application of high-resolution DTI and LGE-CMR revealed the detailed organization of anisotropic infarct structure at a chronic state. This information enhances our understanding of chronic post-infarction remodeling in large animal and human hearts
Assessing the impact of the Australia-United States Free Trade Agreement on Australian and global medicines policy
On 1 January 2005, a controversial trade agreement entered into force between Australia and the United States. Though heralded by the parties as facilitating the removal of barriers to free trade (in ways not achievable in multilateral fora), it also contained many trade-restricting intellectual property provisions and others uniquely related to altering pharmaceutical regulation and public health policy in Australia. The latter appear to have particularly focused on the world-respected process of federal government reimbursement after expert cost-effectiveness evaluation, popularly known as the Pharmaceutical Benefits Scheme ('PBS'). It remains uncertain what sort of impacts – if any – the Australia-United States Free Trade Agreement ('AUSFTA') will have on PBS processes such as reference pricing and their important role in facilitating equitable and affordable access to essential medicines. This is now the field of inquiry for a major three year Australian Research Council ('ARC')-funded study bringing together a team of senior researchers in regulatory theory from the Australian National University and pharmacoeconomics from the University of Newcastle. The project proposes to monitor, assess and analyse the real and potential impacts of the AUSFTA in this area, providing Australian policy-makers with continuing expertise and options. To the extent that the AUSFTA medicines provisions may represent an important precedent in a global strategy by industry on cost-effectiveness evaluation of pharmaceuticals, the study will also be of great interest to policy makers in other jurisdictions
The numerical solution of forward–backward differential equations: Decomposition and related issues
NOTICE: this is the author’s version of a work that was accepted for publication in Journal of computational and applied mathematics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of computational and applied mathematics, 234,(2010), doi: 10.1016/j.cam.2010.01.039This journal article discusses the decomposition, by numerical methods, of solutions to mixed-type functional differential equations (MFDEs) into sums of “forward” solutions and “backward” solutions
On the measurement and modelling of high pressure flows in poppet valves under steady-state and transient conditions
Flow coefficients of intake valves and port combinations were determined experimentally for
a compressed nitrogen engine under steady-state and dynamic flow conditions for inlet
pressures up to 3.2 MPa. Variable valve timing was combined with an indexed parked piston
cylinder unit for testing valve flows at different cylinder volumes whilst maintaining realistic
in-cylinder transient pressure profiles by simply using a fixed area outlet orifice. A one-dimensional modelling approach describing three-dimensional valve flow characteristics has
been developed by the use of variable flow coefficients that take into account the
propagation of flow jets and their boundaries as a function of downstream/upstream
pressure ratios. The results obtained for the dynamic flow cases were compared with steadystate
results for the cylinder to inlet port pressure ratios ranges from 0.18 to 0.83. The
deviation of flow coefficients for both cases is discussed using pulsatile flow theory. The key
findings include: 1. For a given valve lift, the steady-state flow coefficients fall by up to 21
percent with increasing cylinder/manifold pressure ratios within the measured range given
above; 2. Transient flow coefficients deviated from those measured for the steady-state flow
as the valve lift increases beyond a critical value of approximately 0.5 mm. The deviation can
be due to the insufficient time of the development of steady state boundary layers, which
can be quantified by the instantaneous Womersley number defined by using the transient
hydraulic diameter. We show that it is possible to predict deviations of the transient valve
flow from the steady-state measurements alone
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Characteristics of Freebase Cocaine Psychosis.
Psychosis was present in 29 percent of cocaine-disordered patients hospitalized in 1985 during an epidemic of freebase cocaine abuse in the Bahamas. Record reviews revealed that a variety of psychotic phenomenologic patterns were present. Prior major mental disorders and increased dosage of cocaine were more common among psychotic than non-psychotic patients. Violent behavior was common among cocaine patients, especially those with psychosis. We conclude that freebase cocaine psychosis is neither rare nor benign
Outcomes After Virologic Failure of First-Line ART in South Africa
Article approval pendingTo determine initial 24-week outcomes among prospectively enrolled patients with failure of initial antiretroviral therapy (ART)
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