32,999 research outputs found
A Review of Ankylosing Spondylitis
Ankylosing spondylitis (AS) is a systemic autoimmune disorder that induces ankylosis of the spine (fusion of the vertebrae at their various joints) and inflammatory arthritis of peripheral joints among other symptoms. Overexpression of cytokines, the presence of genetic mutations not exclusive to the human leucocyte antigen (HLA)-B27 region, and environmental factors all have large roles in the progressive development of AS. Although a definitive pathology continues to be sought after, researchers believe the adaptive immune system in AS patients attacks fibrocartilaginous entheses (supportive connective tissue between bone and attached structures like tendon, ligament, and fascia).
AS markedly reduces proper systemic functioning in several areas of human physiology, including the musculoskeletal, cardiovascular, neurological, psychiatric, and reproductive systems in both genders. A diagnosis for this disease requires the presentation of several qualifying symptoms, namely chronic inflammatory back pain, peripheral joint arthritis, enthesitis (inflammation of the enthesis not associated with a joint), uveitis (inflammation of the uvea or inner eye layer), and positive response to non-steroidal anti-inflammatory drugs (NSAIDs), with radiological support through x-ray or magnetic resonance imaging (MRI). Upon an AS diagnosis, patients should engage in healthy lifestyle changes, non-impact exercise, and taking NSAIDs as the first pharmacological treatment. Symptoms unresolved by NSAIDs are then treated with disease modifying antirheumatic drugs (DMARDs) and/or biologic medications like a monoclonal TNFα antibody to prevent further disease progression. Continued research to understand the association between AS and interleukin (IL)-17/IL-23 is needed for development of additional biologic treatments
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Lord Coke, the Restatement, and Modern Subsurface Trespass Law
The First Restatement of Property provides that “‘property’ . . . denote[s] legal relations between persons with respect to a thing.” The “thing” considered in this article is the subsurface of real property, and the legal relationship involved in the extent to which persons may deal with invasions of their right to exclude trespassers is a fundamental incident of property ownership, this right, like other incidents, neither is nor should be absolute. The precise focus of this article is to consider how courts have treated subsurface invasions and to argue that the Second Restatement of Torts, which states that any subsurface intrusion is actionable, should be revised. The right to exclude trespassers from the subsurface of real property should be much more limited: subsurface trespass should not be actionable whenever the trespasser’s subsurface intrusion accomplishes an important societal need (including private commercial needs) if the subsurface owner suffers no actual and substantial harm. And because courts have largely refused to find harmless deep subsurface invasions actionable, the ALI should consider whether the Second Restatement of Torts, which essentially embraces Lord Coke’s ad coelum doctrine, accurately reflects the trend of subsurface trespass case law.The Kay Bailey Hutchison Center for Energy, Law, and Busines
Gravitational radiation from the r-mode instability
The instability in the r-modes of rotating neutron stars can (in principle)
emit substantial amounts of gravitational radiation (GR) which might be
detectable by LIGO and similar detectors. Estimates are given here of the
detectability of this GR based the non-linear simulations of the r-mode
instability by Lindblom, Tohline and Vallisneri. The burst of GR produced by
the instability in the rapidly rotating 1.4 solar mass neutron star in this
simulation is fairly monochromatic with frequency near 960 Hz and duration
about 100 s. A simple analytical expression is derived here for the optimal S/N
for detecting the GR from this type of source. For an object located at a
distance of 20 Mpc we estimate the optimal S/N to be in the range 1.2 to about
12.0 depending on the LIGO II configuration.Comment: 8 pages, 4 figure
Integrating Computer Applications Into Economics Electives
Typically, undergraduate economics electives focus on content rather than methods, in spite of the fact that empirical work is fundamental to the practice of economics. This article describes an alternative approach to teaching content by using computer applications that emphasise the empirical testing or applications of the theory. Students enjoy economics courses more when they are taught in this way and lab assignments provide opportunities to teach a broad skill set that is important to many undergraduate economics majors.
GP prescribing of nicotine replacement and bupropion to aid smoking cessation in England and Wales
Aims Prescribing nicotine replacement therapy (NRT) or bupropion for smoking cessation is of considerable importance to public health but little is known about prescribing practices. This paper examines general practitioners' (GPs') prescribing patterns in Britain where these drugs are reimbursed. The results have implications for other health-care systems considering introducing reimbursement.Design, participants and setting Postal survey conducted in 2002 of a random sample of 1088 GPs in England and Wales, of whom 642 (59%) responded.Measures Number of requests GPs reported having received from patients for NRT and bupropion over the past month, the number of prescriptions they reported issuing and ratings of attitudes to these medications.Findings GPs reported receiving an average of 4.3 requests for NRT and 1.9 for bupropion in the previous month. They reported issuing 3.5 prescriptions for NRT and 1.2 for bupropion. Almost all GPs accepted that NRT (95%) and bupropion (97%) should be reimbursable on National Health Service (NHS) prescription. However, a significant minority of those who received requests for prescriptions did not issue any (81% for NRT and 26% for bupropion). This was related to whether they thought these products should be available on NHS prescription for both NRT and bupropion (OR = 0.66, P < 0.05), which in turn was related to beliefs about whether smokers should have to pay for treatment themselves, the cost-effectiveness of NRT/bupropion and the low priority they would give NRT/bupropion in the drug budget. For bupropion, concern about side-effects independently predicted not prescribing [odds ratio (OR) = 1.46, P < 0.03].Conclusion In the British health-care system, which has a well-established system for technology assessment and professionally endorsed guidelines, a significant minority of GPs decline all patient requests for stop-smoking medicines
Low energy operation of the DIAMOND light source
Abstract Within the last decade storage ring free-electron lasers (SRFELs) have reached UV output wavelengths and beyond: several facilities have achieved down to 250nm and quite recently below 200nm. The design of DIAMOND, the third-generation replacement for the existing SRS light source at Daresbury Laboratory, has been optimised at 3 GeV to provide high quality output for the scientific community, mainly from a range of insertion devices. In this paper we propose an additional DIAMOND regime at 1-1.5 GeV in an attempt also to include an SRFEL which would be of major benefit to users needing high quality, high brightness UV/VUV radiation. Such variable ring operating energy will have significant implications, not least in achieving acceptable beam lifetimes. In addition, enhanced beam coherent instabilities (notably microwave) at low energy will affect the single bunch length (peak current) and energy spread which will in turn limit the achievable FEL gain. All these factors will have to be assessed in the detailed design stages of DIAMOND. DIAMOND LIGHT SOURCE The recent successful demonstration of an SRFEL on the ELETTRA light source [1], together with earlier experience at LURE (Super-ACO) and elsewhere, has encouraged interest in the incorporation of such advanced facilities in all leading light sources. The normal operating mode of DIAMOND at 3GeV is described in detail elsewhere FEL OPERATING MODE When operating in optimised FEL mode, the storage ring will be populated with bunches spaced apart in time by twice the round trip time in the FEL cavity, ensuring energy transfer occurs as frequently as possible; the cavity length is always chosen to be a sub-harmonic of the storage ring circumference, whilst satisfying other, practical constraints. The final circumference of the DIAMOND storage ring has not yet been fixed but may be finalised at 528 m (an increase on the present 489 m layout [2] to budget for additional elements), giving a harmonic number of 880 at 500 MHz RF frequency. With 8 equally spaced bunches this leads to a required cavity length of 33 m, which is reasonable (cf. the ELETTRA device which has a cavity length of 32.4 m [1]). Since a very small vertical emittance is not necessary for FEL operation, a conservative coupling value of 3% has been assumed for these calculations, which should both be readily achievable and provide a satisfactory Touschek lifetime; both greater coupling and larger emittance could be selected if necessary. The momentum acceptance will be the primary limit on the beam lifetime at low energies, via Touschek scattering and quantum lifetime; the 4% dynamic and physical acceptance limit specified for 3 GeV operation BUNCH MODELLING To provide peak currents of tens of Amperes, as will be needed for useful FEL gains, bunch currents of several milliamperes are required. At these currents the effects of bunch lengthening from potential well distortion (PWD) and from the microwave instability (MI) are large, but are beneficial in that they provide low enough number densities within the bunches to give an acceptable Touschek lifetime; however the issue is whether sufficient peak current can then be maintained, together with acceptable energy spread. The ZAP code [3] was used to predict the effect on bunch parameters of PWD and MI (details are given in [4]); however, the implementation of Brück's approximatio
Automatic device for shell freezing of liquids
Unit is insulated enclosure designed to contain liquid nitrogen. It also includes set of stainless steel rotating rods for holding vessels containing liquids to be frozen, and electric drive mechanism for rotating these rods. Present device will accept 10 vessels at a time
Development and demonstration of an on-board mission planner for helicopters
Mission management tasks can be distributed within a planning hierarchy, where each level of the hierarchy addresses a scope of action, and associated time scale or planning horizon, and requirements for plan generation response time. The current work is focused on the far-field planning subproblem, with a scope and planning horizon encompassing the entire mission and with a response time required to be about two minutes. The far-feld planning problem is posed as a constrained optimization problem and algorithms and structural organizations are proposed for the solution. Algorithms are implemented in a developmental environment, and performance is assessed with respect to optimality and feasibility for the intended application and in comparison with alternative algorithms. This is done for the three major components of far-field planning: goal planning, waypoint path planning, and timeline management. It appears feasible to meet performance requirements on a 10 Mips flyable processor (dedicated to far-field planning) using a heuristically-guided simulated annealing technique for the goal planner, a modified A* search for the waypoint path planner, and a speed scheduling technique developed for this project
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