A randomised, double-blind, phase 3 study comparing the efficacy and safety of ceftazidime/avibactam plus metronidazole versus meropenem for complicated intra-abdominal infections in hospitalised adults in Asia

Ceftazidime/avibactam comprises the broad-spectrum cephalosporin ceftazidime and the non-β-lactam β-lactamase inhibitor avibactam. This phase 3, randomised, double-blind study (NCT01726023) assessed the efficacy and safety of ceftazidime/avibactam plus metronidazole compared with meropenem in patients with complicated intra-abdominal infection (cIAI) in Asian countries. Subjects aged 18–90 years and hospitalised with cIAI requiring surgical intervention were randomised 1:1 to receive every 8 h either: ceftazidime/avibactam (2000/500 mg, 2-h infusion) followed by metronidazole (500 mg, 60-min infusion); or meropenem (1000 mg, 30-min infusion). Non-inferiority of ceftazidime/avibactam plus metronidazole to meropenem was concluded if the lower limit of the 95% confidence interval (CI) for the between-group difference in clinical cure rate was greater than −12.5% at the test-of-cure (TOC) visit (28–35 days after randomisation) in the clinically evaluable (CE) population. Safety was also evaluated. Of 441 subjects randomised, 432 received at least one dose of study medication (ceftazidime/avibactam plus metronidazole, n = 215; meropenem, n = 217). In the CE population at the TOC visit, non-inferiority of ceftazidime/avibactam plus metronidazole to meropenem was demonstrated, with clinical cure reported for 93.8% (166/177) and 94.0% (173/184) of subjects, respectively (between-group difference, −0.2, 95% CI −5.53 to 4.97). The clinical cure rate with ceftazidime/avibactam plus metronidazole was comparable in subjects with ceftazidime-non-susceptible and ceftazidime-susceptible isolates (95.7% vs. 92.1%, respectively). Adverse events were similar between the study groups. Ceftazidime/avibactam plus metronidazole was non-inferior to meropenem in the treatment of cIAIs in Asian populations and was effective against ceftazidime-non-susceptible pathogens. No new safety concerns were identified

Superfluid Flow Past an Array of Scatterers

We consider a model of nonlinear superfluid flow past a periodic array of point-like scatterers in one dimension. An application of this model is the determination of the critical current of a Josephson array in a regime appropriate to a Ginzburg-Landau formulation. Here, the array consists of short normal-metal regions, in the presence of a Hartree electron-electron interaction, and embedded within a one-dimensional superconducting wire near its critical temperature, $Tc$. We predict the critical current to depend linearly as $A (Tc-T)$, while the coefficient $A$ depends sensitively on the sizes of the superconducting and normal-metal regions and the strength and sign of the Hartree interaction. In the case of an attractive interaction, we find a further feature: the critical current vanishes linearly at some temperature $T*$ less than $Tc$, as well as at $Tc$ itself. We rule out a simple explanation for the zero value of the critical current, at this temperature $T*$, in terms of order parameter fluctuations at low frequencies.Comment: 23 pages, REVTEX, six eps-figures included; submitted to PR

Ceftazidime-avibactam versus meropenem in nosocomial pneumonia, including ventilator-associated pneumonia (REPROVE): a randomised, double-blind, phase 3 non-inferiority trial

Background: Nosocomial pneumonia is commonly associated with antimicrobial-resistant Gram-negative pathogens. We aimed to assess the efficacy and safety of ceftazidime-avibactam in patients with nosocomial pneumonia, including ventilator-associated pneumonia, compared with meropenem in a multinational, phase 3, double-blind, non-inferiority trial (REPROVE). Methods: Adults with nosocomial pneumonia (including ventilator-associated pneumonia), enrolled at 136 centres in 23 countries, were randomly assigned (1:1) to 2000 mg ceftazidime and 500 mg avibactam (by 2 h intravenous infusion every 8 h) or 1000 mg meropenem (by 30-min intravenous infusion every 8 h) for 7-14 days; regimens were adjusted for renal function. Computer-generated randomisation codes were stratified by infection type and geographical region with a block size of four. Participants and investigators were masked to treatment assignment. The primary endpoint was clinical cure at the test-of-cure visit (21-25 days after randomisation). Non-inferiority was concluded if the lower limit of the two-sided 95% CI for the treatment difference was greater than -12·5% in the coprimary clinically modified intention-to-treat and clinically evaluable populations. This trial is registered with ClinicalTrials.gov (NCT01808092) and EudraCT (2012-004006-96). Findings: Between April 13, 2013, and Dec 11, 2015, 879 patients were randomly assigned. 808 patients were included in the safety population, 726 were included in the clinically modified intention-to-treat population, and 527 were included in the clinically evaluable population. Predominant Gram-negative baseline pathogens in the microbiologically modified intention-to-treat population (n=355) were Klebsiella pneumoniae (37%) and Pseudomonas aeruginosa (30%); 28% were ceftazidime-non-susceptible. In the clinically modified intention-to-treat population, 245 (68·8%) of 356 patients in the ceftazidime-avibactam group were clinically cured, compared with 270 (73·0%) of 370 patients in the meropenem group (difference -4·2% [95% CI -10·8 to 2·5] ). In the clinically evaluable population, 199 (77·4%) of 257 participants were clinically cured in the ceftazidime-avibactam group, compared with 211 (78·1%) of 270 in the meropenem group (difference -0·7% [95% CI -7·9 to 6·4]). Adverse events occurred in 302 (75%) of 405 patients in the ceftazidime-avibactam group versus 299 (74%) of 403 in the meropenem group (safety population), and were mostly mild or moderate in intensity and unrelated to study treatment. Serious adverse events occurred in 75 (19%) patients in the ceftazidime-avibactam group and 54 (13%) patients in the meropenem group. Four serious adverse events (all in the ceftazidime-avibactam group) were judged to be treatment related. Interpretation: Ceftazidime-avibactam was non-inferior to meropenem in the treatment of nosocomial pneumonia. These results support a role for ceftazidime-avibactam as a potential alternative to carbapenems in patients with nosocomial pneumonia (including ventilator-associated pneumonia) caused by Gram-negative pathogens. Funding: AstraZeneca

Magnetic fields in cosmic particle acceleration sources

We review here some magnetic phenomena in astrophysical particle accelerators associated with collisionless shocks in supernova remnants, radio galaxies and clusters of galaxies. A specific feature is that the accelerated particles can play an important role in magnetic field evolution in the objects. We discuss a number of CR-driven, magnetic field amplification processes that are likely to operate when diffusive shock acceleration (DSA) becomes efficient and nonlinear. The turbulent magnetic fields produced by these processes determine the maximum energies of accelerated particles and result in specific features in the observed photon radiation of the sources. Equally important, magnetic field amplification by the CR currents and pressure anisotropies may affect the shocked gas temperatures and compression, both in the shock precursor and in the downstream flow, if the shock is an efficient CR accelerator. Strong fluctuations of the magnetic field on scales above the radiation formation length in the shock vicinity result in intermittent structures observable in synchrotron emission images. Resonant and non-resonant CR streaming instabilities in the shock precursor can generate mesoscale magnetic fields with scale-sizes comparable to supernova remnants and even superbubbles. This opens the possibility that magnetic fields in the earliest galaxies were produced by the first generation Population III supernova remnants and by clustered supernovae in star forming regions.Comment: 30 pages, Space Science Review

Large-Eddy Simulations of Magnetohydrodynamic Turbulence in Heliophysics and Astrophysics

We live in an age in which high-performance computing is transforming the way we do science. Previously intractable problems are now becoming accessible by means of increasingly realistic numerical simulations. One of the most enduring and most challenging of these problems is turbulence. Yet, despite these advances, the extreme parameter regimes encountered in space physics and astrophysics (as in atmospheric and oceanic physics) still preclude direct numerical simulation. Numerical models must take a Large Eddy Simulation (LES) approach, explicitly computing only a fraction of the active dynamical scales. The success of such an approach hinges on how well the model can represent the subgrid-scales (SGS) that are not explicitly resolved. In addition to the parameter regime, heliophysical and astrophysical applications must also face an equally daunting challenge: magnetism. The presence of magnetic fields in a turbulent, electrically conducting fluid flow can dramatically alter the coupling between large and small scales, with potentially profound implications for LES/SGS modeling. In this review article, we summarize the state of the art in LES modeling of turbulent magnetohydrodynamic (MHD) ows. After discussing the nature of MHD turbulence and the small-scale processes that give rise to energy dissipation, plasma heating, and magnetic reconnection, we consider how these processes may best be captured within an LES/SGS framework. We then consider several special applications in heliophysics and astrophysics, assessing triumphs, challenges,and future directions

State of the climate in 2013

In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earths surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. © 2014, American Meteorological Society. All rights reserved

Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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