1,659 research outputs found

    Trajectory optimization and guidance for an aerospace plane

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    The first step in the approach to developing guidance laws for a horizontal take-off, air breathing single-stage-to-orbit vehicle is to characterize the minimum-fuel ascent trajectories. The capability to generate constrained, minimum fuel ascent trajectories for a single-stage-to-orbit vehicle was developed. A key component of this capability is the general purpose trajectory optimization program OTIS. The pre-production version, OTIS 0.96 was installed and run on a Convex C-1. A propulsion model was developed covering the entire flight envelope of a single-stage-to-orbit vehicle. Three separate propulsion modes, corresponding to an after burning turbojet, a ramjet and a scramjet, are used in the air breathing propulsion phase. The Generic Hypersonic Aerodynamic Model Example aerodynamic model of a hypersonic air breathing single-stage-to-orbit vehicle was obtained and implemented. Preliminary results pertaining to the effects of variations in acceleration constraints, available thrust level and fuel specific impulse on the shape of the minimum-fuel ascent trajectories were obtained. The results show that, if the air breathing engines are sized for acceleration to orbital velocity, it is the acceleration constraint rather than the dynamic pressure constraint that is active during ascent

    Clinical efficacy, radiographic and safety findings through 2 years of golimumab treatment in patients with active psoriatic arthritis: results from a long-term extension of the randomised, placebo-controlled GO-REVEAL study

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    Objectives: To assess long-term golimumab efficacy/safety in patients with active psoriatic arthritis (PsA).<p></p> Methods Adult PsA patients (≥3 swollen, ≥3 tender joints, active psoriasis) were randomly assigned to subcutaneous injections of placebo, golimumab 50 mg or 100 mg every 4 weeks (q4wks) through week 20. All patients received golimumab 50 or 100 mg beginning week 24. Findings through 2 years are reported. Efficacy evaluations included ≥20% improvement in American College of Rheumatology (ACR20) response, good/moderate response in Disease Activity Scores incorporating 28 joints and C-reactive protein (DAS28-CRP), ≥75% improvement in Psoriasis Area and Severity Index (PASI75) and changes in PsA-modified Sharp/van der Heijde scores (SHS).<p></p> Results: Golimumab treatment through 2 years was effective in maintaining clinical response (response rates: ACR20 63%–70%, DAS28-CRP 77%–86%, PASI75 56%–72%) and inhibiting radiographic progression (mean change in PsA-modified SHS in golimumab-treated patients: −0.36), with no clear difference between doses. No new safety signals were identified through 2 years. With the study's tuberculosis screening and prophylactic measures, no patient developed active tuberculosis through 2 years.<p></p> Conclusions: Golimumab 50 and 100 mg for up to 2 years yielded sustained clinical and radiographic efficacy when administered to patients with active PsA. Increasing the golimumab dose from 50 to 100 mg q4wks added limited benefit. Golimumab safety through up to 2 years was consistent with other antitumour necrosis factor α agents used to treat PsA. Treatment of patients with latent tuberculosis identified at baseline appeared to be effective in inhibiting the development of active tuberculosis.<p></p&gt

    Rings of real functions in pointfree topology

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    AbstractThis paper deals with the algebra F(L) of real functions on a frame L and its subclasses LSC(L) and USC(L) of, respectively, lower and upper semicontinuous real functions. It is well known that F(L) is a lattice-ordered ring; this paper presents explicit formulas for its algebraic operations which allow to conclude about their behaviour in LSC(L) and USC(L).As applications, idempotent functions are characterized and previous pointfree results about strict insertion of functions are significantly improved: general pointfree formulations that correspond exactly to the classical strict insertion results of Dowker and Michael regarding, respectively, normal countably paracompact spaces and perfectly normal spaces are derived.The paper ends with a brief discussion concerning the frames in which every arbitrary real function on the α-dissolution of the frame is continuous

    Treatment recommendations for psoriatic arthritis

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    Objective: To develop comprehensive recommendations for the treatment of the various clinical manifestations of psoriatic arthritis (PsA) based on evidence obtained from a systematic review of the literature and from consensus opinion. Methods: Formal literature reviews of treatment for the most significant discrete clinical manifestations of PsA (skin and nails, peripheral arthritis, axial disease, dactylitis and enthesitis) were performed and published by members of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA). Treatment recommendations were drafted for each of the clinical manifestations by rheumatologists, dermatologists and PsA patients based on the literature reviews and consensus opinion. The level of agreement for the individual treatment recommendations among GRAPPA members was assessed with an online questionnaire. Results: Treatment recommendations were developed for peripheral arthritis, axial disease, psoriasis, nail disease, dactylitis and enthesitis in the setting of PsA. In rotal, 19 recommendations were drafted, and over 80% agreement was obtained on 16 of them. In addition, a grid that factors disease severity into each of the different disease manifestations was developed to help the clinician with treatment decisions for the individual patient from an evidenced-based perspective. Conclusions: Treatment recommendations for the cardinal physical manifestations of PsA were developed based on a literature review and consensus between rheumatologists and dermatologists. In addition, a grid was established to assist in therapeutic reasoning and decision making for individual patients. It is anticipated that periodic updates will take place using this framework as new data become available

    Markers of inflammation and bone remodelling associated with improvement in clinical response measures in psoriatic arthritis patients treated with golimumab

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    <p>Objective To determine serum biomarker associations with clinical response to golimumab treatment in patients with psoriatic arthritis (PsA).</p> <p>Methods GO–REVEAL was a randomised, placebo-controlled study of golimumab in patients with active PsA. Samples were collected from 100 patients at baseline, week 4 and week 14, and analysed for serum-based biomarkers and protein profiling (total 92 markers); data were correlated with clinical measures at week 14.</p> <p>Results Serum levels of a subset of proteins (apolipoprotein C III, ENRAGE, IL-16, myeloperoxidase, vascular endothelial growth factor, pyridinoline, matrix metalloproteinase 3, C-reactive protein (CRP), carcinoembryonic antigen, intercellular adhesion molecule 1 and macrophage inflammatory protein 1α) at baseline or week 4 were strongly associated with American College of Rheumatology 20% improvement (ACR20) response and/or disease activity score in 28 joints (DAS28) at week 14. A smaller subset of proteins was significantly associated with a 75% improvement in the psoriasis area and severity index score (PASI75) at week 14, (adiponectin, apolipoprotein CIII, serum glutamic oxaloacetic transaminase, and tumour necrosis factor α). Subsets of proteins were identified as potentially predictive of clinical response for each of the clinical measures, and the power of these biomarker panels to predict clinical response to golimumab treatment was stronger than for CRP alone.</p> <p>Conclusions This analysis provides insight into several panels of markers that may have utility in identifying PsA patients likely to have ACR20, DAS28, or PASI75 responses following golimumab treatment.</p&gt

    A survey of cost-sensitive decision tree induction algorithms

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    The past decade has seen a significant interest on the problem of inducing decision trees that take account of costs of misclassification and costs of acquiring the features used for decision making. This survey identifies over 50 algorithms including approaches that are direct adaptations of accuracy based methods, use genetic algorithms, use anytime methods and utilize boosting and bagging. The survey brings together these different studies and novel approaches to cost-sensitive decision tree learning, provides a useful taxonomy, a historical timeline of how the field has developed and should provide a useful reference point for future research in this field

    Minimum-fuel aeroassisted coplanar orbit transfer using lift-modulation

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76954/1/AIAA-1983-2094-112.pd
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