Showing papers by "Michael D. Smith published in 2014"

Volatile and organic compositions of sedimentary rocks in Yellowknife Bay, Gale crater, Mars.

Abstract: H2O, CO2, SO2, O2, H2, H2S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H2O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the CO2. Concurrent evolution of O2 and chlorinated hydrocarbons suggests the presence of oxychlorine phase(s). Sulfides are likely sources for sulfur-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic carbon sources may be preserved in the mudstone; however, the carbon source for the chlorinated hydrocarbons is not definitively of martian origin.

Efficacy and safety of intravenous tanezumab for the symptomatic treatment of osteoarthritis: 2 randomized controlled trials versus naproxen.

Abstract: Objective. Two studies evaluated efficacy and safety of tanezumab versus naproxen for treatment of knee or hip osteoarthritis (OA). Methods. Randomized controlled studies [NCT00830063 (Study 1015, n = 828) and NCT00863304 (Study 1018, n = 840)] of subjects with hip or knee OA compared intravenous tanezumab (5 mg or 10 mg) to placebo and naproxen (500 mg twice daily). Coprimary outcomes were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain, WOMAC Physical Function (0–10 numerical rating scale), and patient’s global assessment of OA at Week 16. Results. In both studies, tanezumab reduced pain versus placebo [least squares mean differences, 95% CI, tanezumab 5 mg: −1.21 (−1.72, −0.70); −1.13 (−1.65, −0.62); tanezumab 10 mg: −0.91 (−1.42, −0.40); −0.80 (−1.32, −0.29)], and improved function and global scores. Tanezumab 5 mg produced greater pain reduction [−0.76 (−1.28, −0.25); −0.69 (−1.21, −0.17)], and favorable functional and global outcomes versus naproxen. Pain reductions with tanezumab 10 mg versus naproxen did not reach significance, unlike functional (both studies) and global (1 study) outcomes; thus, tanezumab 10 mg was not superior to naproxen, and predefined statistical testing procedures were not met, allowing for conclusion of superiority of tanezumab 5 mg over naproxen despite replicated favorable coprimary outcomes. Tanezumab was associated with greater incidence of peripheral sensory adverse events (paresthesia, hyperesthesia, hypoesthesia, burning sensation), pain in extremity, peripheral edema, and arthralgia. Overall frequency and discontinuations as a result of adverse events were similar to placebo and naproxen. Conclusion. Tanezumab provides efficacious treatment of knee or hip OA and may have therapeutic utility in patients with OA who experience inadequate analgesia with nonsteroidal antiinflammatory drugs.

Efficacy and safety of tanezumab added on to diclofenac sustained release in patients with knee or hip osteoarthritis: a double-blind, placebo-controlled, parallel-group, multicentre phase III randomised clinical trial

Abstract: Objectives Tanezumab, a monoclonal antibody, inhibits nerve growth factor and reduces chronic pain. This randomised, double-blind, controlled multicentre study was conducted to evaluate the efficacy and safety of tanezumab added to oral diclofenac sustained release (DSR) in patients with hip or knee osteoarthritis (OA) pain. Methods Patients (N=604) with moderate to severe knee or hip OA tolerating stable DSR were randomised and treated with DSR 75 mg twice daily combined with intravenous tanezumab 10, 5 or 2.5 mg or placebo at weeks 0, 8 and 16. Co-primary efficacy endpoints (Western Ontario and McMaster Universities OA Index (WOMAC) Pain and Physical Function subscales and patient9s global assessment of OA) were assessed at week 16. Results All co-primary endpoints were significantly improved for all tanezumab+DSR groups versus placebo+DSR (p≤0.039). The incidence of adverse events of abnormal peripheral sensation was lower than in previous tanezumab trials. No new safety signals emerged. Overall incidence of adverse events was higher with tanezumab+DSR (45.2%–49.7%) than with placebo+DSR (34.9%); serious adverse event rates were similar across treatments (5.3%–7.6%). Osteonecrosis was reported in six of 452 patients with tanezumab+DSR (1.3%), but an external adjudication committee did not confirm osteonecrosis in any patient. Conclusions Addition of tanezumab to DSR resulted in significant improvements in pain, function and global assessments in patients with OA. Although no new safety signals were observed, the higher incidence of adverse events in the tanezumab+diclofenac group suggests that combination therapy is unfavourable. Further investigations of tanezumab monotherapy for OA pain treatment are required. Clinical trial registration number NCT00864097

Thermal Tides During the 2001 Martian Global-Scale Dust Storm

Abstract: The 2001 (Mars Year 25) global dust storm radically altered the dynamics of the Martian atmosphere. Using observations from the Thermal Emission Spectrometer onboard the Mars Global Surveyor spacecraft and Mars WRF general circulation model simulations, we examine the changes to thermal tides and planetary waves caused by the storm. We find that the extratropical diurnal migrating tide is dramatically enhanced during the storm, particularly in the southern hemisphere, reaching amplitudes of more than 20 K. The tropical diurnal migrating tide is weakened to almost undetectable levels. The diurnal Kelvin waves are also significantly weakened, particularly during the period of global expansion at Ls=200deg-210deg. In contrast, the westward propagating diurnal wavenumber 2 tide strengthens to 4-8 K at altitudes above 30km. The wavenumber 1 stationary wave reaches amplitudes of 10-12 K at 50deg-70degN, far larger than is typically seen during this time of year. The phase of this stationary wave and the enhancement of the diurnal wavenumber 2 tide appear to be responses to the high-altitude westward propagating equatorial wavenumber 1 structure in dust mixing ratio observed during the storm in previous works. This work provides a global picture of dust storm wave dynamics that reveals the coupling between the tropics and high-latitude wave responses. We conclude that the zonal distribution of thermotidal forcing from atmospheric aerosol concentration is as important to understanding the atmospheric wave response as the total global mean aerosol optical depth.

The vertical distribution of Martian aerosol particle size

Abstract: Using approximately 410 limb-viewing observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), we retrieve the vertical distribution of Martian dust and water ice aerosol particle sizes. We find that dust particles have an effective radius of 1.0 µm over much of the atmospheric column below 40 km throughout the Martian year. This includes the detached tropical dust layers detected in previous studies. Little to no variation with height is seen in dust particle size. Water ice clouds within the aphelion cloud belt exhibit a strong sorting of particle size with height, however, and the effective radii range from >3 µm below 20 km to near 1.0 µm at 40 km altitude. Conversely, water ice clouds in the seasonal polar hoods show a near-uniform particle size with an effective radius of approximately 1.5 µm throughout the atmospheric column.

Mars Photoelectron Energy and Pitch Angle Dependence on Intense Lower Atmospheric Dust Storms

Abstract: We have conducted a survey of the Mars Global Surveyor (MGS) electron data across all the pitch angles of 12 usable energy bins (11–746 eV) for dayside photoelectron observations over regions of strong crustal fields. Studies have shown that solar EUV flux is the main controlling factor, but dust storms play an important role as well. Our study of different energies and pitch angles has shown that the unusual bimodal solar flux dependence is not a common feature but mainly found in low energies and a few bins of higher-energy channels. By multiplying time-history dust opacity with a solar EUV proxy as a new controlling function, the statistically significant increase of the correlation of photoelectron flux against this function indicates that dust storms have a long-lasting influence on high-altitude photoelectron fluxes, especially at low energies and the pitch angle source regions of high-energy channels. The correlation increases experienced by the pitch angle source regions of all examined energy channels suggest that dust storms' influence most likely happens in the thermosphere-ionosphere source region of the photoelectrons, rather than at exospheric altitudes at or above MGS. Furthermore, by isolating the global-scale dust storm in Mars year 25 (2001) from the rest, the results suggest that this storm is entirely responsible for the second solar flux-dependent trend. While not excluding the possibility of this phenomenon being a one-time event, we hypothesize that there is a threshold of dust opacity at which the low-altitude dust's influence on high-altitude photoelectron fluxes begins to be significant.

EU-China relations and the limits of economic diplomacy

Abstract: This paper addresses a key problem in EU-China economic relations: the capacity of the EU to exert leverage through its economic diplomacy in the context of key economic trends, policy dilemmas, and processes of governance The paper begins by identifying key elements of the EU’s economic diplomacy and their relationship to key functions: deliberation, representation, communication, and negotiation It continues by reviewing key trends and challenges in EU-China economic relations, in terms of trade, finance/investment, and broader issues of economic performance, with special reference to the problems emanating from the current economic turbulence both in the EU and in the broader global political economy It then identifies a number of key policy dilemmas for the EU in areas such as trade defense/trade promotion, environment/development, security/commercial priorities, investment/sovereignty, and explores these in terms of three key concepts: orientation, coordination, and effectiveness In pursuing this analysis, the paper relates these trends and dilemmas to attempts to govern EU-China economic relations: public/private, bilateral/multilateral, and regulatory/political In the final section of the paper, these efforts are evaluated in the context of the EU’s economic diplomacy, with relation to key actors, processes, and outcomes and to the key functions of deliberation, representation, communication, and negotiation

The European Union and the Contradictions of Complex Interregionalism

Abstract: This chapter focuses on the evolution of EU interregional strategy through the lens of the concept of ‘complex interregionalism’, the changing interlinkages of bilateral, interregional and transregional relations that the EU has around the globe. Complex interregionalism offers an analytical tool to understand the significant changes in EU interregional policy over the last few years. In addition to this, the chapter addresses the key institutional drivers of EU complex interregionalism (the Commission, the Council, the member states and more recently the European Parliament) and analyses the implications of their differing interests in interregionalism. Finally, the chapter offers a first evaluation of the implications of the Treaty of Lisbon for EU interregionalism, notably through the creation of the European External Action Service and the increased powers of the European Parliament, before ending with some conclusions for the future of EU complex interregionalism.

Long-term variability of Mars' exosphere based on precise orbital analysis of Mars Global Surveyor and Mars Odyssey

Abstract: A long-term perspective on Mars' exosphere variability at 405 km is provided by merging together density data derived from precise orbit determination of the Mars Global Surveyor and Mars Odyssey (MO) satellites extending from 2001 to 2010. These data are heavily weighted toward afternoon local times at high latitudes in the Southern Hemisphere. Clear long-term solar and annual variations are well captured by empirical formulas. Residuals from the empirical fit show evidence for relative depletions in exosphere density around Mars' closest approach to Earth, which would be consistent with a scavenging mechanism that is dependent on solar wind dynamic pressure. Superimposed on this variation with Mars-Sun distance are positive density residuals during Mars year (MY)25, MY27, and MY29 that are apparently due to elevated dust levels in Mars' middle atmosphere. However, during MY24, MY26, and MY28 there are dust level increases without any corresponding increase in exosphere density. We suspect that this inconsistency is related to a variable ability to sense the response to dust-related effects, imposed by the high-latitude limitations of our measurements combined with interference between the mechanisms that translate middle atmosphere heating to an exosphere response. Evidence also supports the hypothesis that winter helium bulge effects contributed to the inferred interannual density variability during the 2007–2009 solar minimum period, when the O-He transition height likely resided near the ~405 km orbit of MO.

Biased-Coin Randomization

Abstract: The biased coin randomisation is introduced as a procedure to minimize study bias whilst maintaining treatment balance throughout the trial. The range of biased coin randomizations are described for 2 and more than 2 treatment groups, and also for equal and unequal randomization. Biased coin randomizations are described which use both fixed and adaptive levels of coin ‘bias’. The well-known urn model is described as a special representation of the biased coin randomization, and the link is discussed. Finally, the use of the biased coin randomization procedure for balance within covariate strata, and the application to response adaptive randomizations are described. Keywords: Randomisation; biased coin; balance; urn model; adaptive design