To assess whether smoking is a risk factor for developing rheumatoid arthritis (RA).
Meta-analysis.
were observational studies that examined the association between smoking history and the risk of ...developing RA identified through Medline and EMBASE (from 1966 to December 2006), relevant books and a reference search. Two authors independently extracted the following: authors' names, publication year, sample size, participant characteristics, odds ratios (OR) or relative risks, adjustment factors, study design and area where the study was conducted. Data syntheses were based upon random effects model. Summarised syntheses effects were expressed by OR.
Sixteen studies were selected from among 433 articles. For men, summary OR for ever, current and past smokers were 1.89 (95% CI 1.56 to 2.28), 1.87 (1.49 to 2.34) and 1.76 (1.33 to 2.31), respectively. For rheumatoid factor-positive (RF+) RA, summary OR for ever, current and past smokers were 3.02 (2.35 to 3.88), 3.91 (2.78 to 5.50) and 2.46 (1.74 to 3.47), respectively. Summary OR for 20 or more pack-years of smoking was 2.31 (1.55 to 3.41). For women, summary OR for ever, current and past smokers were 1.27 (1.12 to 1.44), 1.31 (1.12 to 1.54) and 1.22 (1.06 to 1.40), respectively. For RF+ RA, summary OR for ever, current and past smokers were 1.34 (0.99 to 1.80), 1.29 (0.94 to 1.77) and 1.21 (0.83 to 1.77). Summary OR for 20 or more pack-years of smoking was 1.75 (1.52 to 2.02).
Smoking is a risk factor for RA, especially RF+ RA men and heavy smokers.
We investigated the applicability of miniature microtremor arrays with a radius of a few meters or less to shallow surveys (up to a few tens of meters). It is shown that the upper limit wavelength ...normalized by the seismometer separation distance s that is analyzable by a miniature array does not depend on the observation instrument as long as the instrument has a self‐noise level that is sufficiently lower than the microtremor intensities; however, it generally depends on the average S‐wave velocity of the ground. This means that a miniature array is useful at soft‐soil sites but not hard‐soil sites. A statistical study in central Japan showed that the penetration depth by a miniature array with s = 1 m ranges from 6 to 12 m; specifically, the depth exceeds 12 m in one quarter of the cases but remains below 6 m in one quarter of the cases. This large variation is due to the variation in the average S‐wave velocity. A miniature array should thus be used in combination with a larger array with an s value of several meters to 20 m. In urbanized areas with high industrial activity, where the microtremor wavefield is likely isotropic, these arrays can be replaced by a linear array. In environments with extremely low signal‐to‐noise ratios, a less efficient zero‐crossing method should be applied to the larger array. An appropriate observation strategy should be selected for a given geoenvironment. Field examples show that our strategy enables efficient and feasible dense surveys.
Plain Language Summary
A microtremor array survey is a non‐destructive, passive method for subsurface exploration. Because such a survey is also easy to conduct and cost‐effective, it is widely used for seismic hazard assessments. It is expected that the benefits can be extended to lunar and planetary exploration. We demonstrate that a miniature microtremor measurement device with a radius of a few meters or less can be used for shallow surveys. The performance of the miniature measurement device does not depend on the observation instrument. This device is effective at soft‐soil sites but not hard‐soil sites. To increase survey feasibility, miniature measurement devices should be used in combination with a larger measurement device. In ground environments with extremely low signal‐to‐noise ratios, larger measurement devices and somewhat less efficient methods must be applied. It is important to select an observation strategy that is appropriate for a given geological environment considering the balance between the efficiency and feasibility of a shallow survey.
Key Points
The applicability of a miniature array with a radius of a few meters or less to shallow surveys is reviewed and summarized
The applicability of a miniature array depends on the average S‐wave velocity of the ground but not on the observation instrument
Illustrative field examples of our strategy, which enables a dense survey to obtain a shallow two‐dimensional velocity section, are shown
Demands are growing rapidly in the operational prediction and applications communities for forecasts that fill the gap between medium-range weather and long-range or seasonal forecasts. Based on the ...potential for improved forecast skill at the subseasonal to seasonal time range, the Subseasonal to Seasonal (S2S) Prediction research project has been established by the World Weather Research Programme/World Climate Research Programme. A main deliverable of this project is the establishment of an extensive database containing subseasonal (up to 60 days) forecasts, 3 weeks behind real time, and reforecasts from 11 operational centers, modeled in part on the The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) database for medium-range forecasts (up to 15 days).
The S2S database, available to the research community since May 2015, represents an important tool to advance our understanding of the subseasonal to seasonal time range that has been considered for a long time as a “desert of predictability.” In particular, this database will help identify common successes and shortcomings in the model simulation and prediction of sources of subseasonal to seasonal predictability. For instance, a preliminary study suggests that the S2S models significantly underestimate the amplitude of the Madden–Julian oscillation (MJO) teleconnections over the Euro-Atlantic sector. The S2S database also represents an important tool for case studies of extreme events. For instance, a multimodel combination of S2S models displays higher probability of a landfall over the islands of Vanuatu 2–3 weeks before Tropical Cyclone Pam devastated the islands in March 2015.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Atmospheric methane (CH4) increased from similar to 900 ppb (parts per billion, or nanomoles per mole of dry air) in 1900 to similar to 1800 ppb in 2010 at a rate unprecedented in any observational ...records. However, the contributions of the various methane sources and sinks to the CH4 increase are poorly understood. Here we use initial emissions from bottom-up inventories for anthropogenic sources, emissions from wetlands and rice paddies simulated by a terrestrial biogeochemical model, and an atmospheric general circulation model (AGCM)-based chemistry-transport model (i.e. ACTM) to simulate atmospheric CH4 concentrations for 1910-2010. The ACTM simulations are compared with the CH4 concentration records reconstructed from Antarctic and Arctic ice cores and firn air samples, and from direct measurements since the 1980s at multiple sites around the globe. The differences between ACTM simulations and observed CH4 concentrations are minimized to optimize the global total emissions using a mass balance calculation. During 1910-2010, the global total CH4 emission doubled from similar to 290 to similar to 580 Tg yr-1. Compared to optimized emission, the bottom-up emission data set underestimates the rate of change of global total CH4 emissions by similar to 30% during the high growth period of 1940-1990, while it overestimates by similar to 380% during the low growth period of 1990-2010. Further, using the CH4 stable carbon isotopic data ( delta 13C), we attribute the emission increase during 1940-1990 primarily to enhancement of biomass burning. The total lifetime of CH4 shortened from 9.4 yr during 1910-1919 to 9 yr during 2000-2009 by the combined effect of the increasing abundance of atomic chlorine radicals (Cl) and increases in average air temperature. We show that changes of CH4 loss rate due to increased tropospheric air temperature and CH4 loss due to Cl in the stratosphere are important sources of uncertainty to more accurately estimate the global CH4 budget from delta 13C observations.
New automated observation systems for use in passenger aircraft to measure atmospheric carbon dioxide (CO2) and other trace species have been developed and are described in this paper. The Continuous ...CO2 Measuring Equipment (CME) is composed mainly of a nondispersive infrared analyzer, a datalogger, and two calibration cylinders for in situ CO2 measurements. The Automatic Air Sampling Equipment (ASE), on the other hand, is designed for flask sampling; the instrument, connected to a metal bellows pump, is made up of a specially designed control board and can accommodate 12 flasks. The CME platform can be used to conduct high-frequency measurements of CO2 for obtaining a detailed spatial observation over a wide area, while ASE, despite the limited flight frequency, can provide useful distributions not only of CO2 but also various trace gas species, as well as their isotopic ratios. ASE and CME are installed on the racks in the forward cargo compartment of the aircraft and the air bypass intake is mounted on the airconditioning duct upstream of the recirculation fan. Both sets of sampling equipment are automatically controlled through input of relevant flight parameters from the aircraft data system. Their deployment in a Boeing 747-400 aircraft was approved by the aviation regulatory agencies in the United States and Japan through issuance of the supplemental type certificate (STC), while the approval for installation of CME in a Boeing 777-200ER was also obtained via STC. First measurement results of CO2 variations obtained by CME and ASE deployed on Japan Airlines (JAL) aircraft are reported herein. PUBLICATION ABSTRACT
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In this study we reexamine nearly four decades of in situ balloon‐based stratospheric observations of SF6 and CO2 with an idealized model and reanalysis products. We use new techniques to account for ...the spatial and temporal inhomogeneity of the sparse balloon profiles and to calculate stratospheric mean ages of air more consistently from the observations with the idealized model. By doing so we are able to more clearly show and account for the variability of mean age of air throughout the bulk of the depth of the stratosphere. From an idealized model guided by the observations, we identify variability in the mean age due to the seasonal cycle of stratospheric transport, the quasi‐biennial oscillation in tropical zonal winds, major volcanic eruptions, and linear trends that vary significantly with altitude. We calculate a negative mean age trend in the lowest 5 km of the stratosphere that agrees within uncertainties with a trend calculated from a set of chemistry climate model mean ages in this layer. The mean age trends reverse sign in the middle and upper stratosphere and are in agreement with a previous positive trend estimate using the same observational data set, although we have substantially reduced the uncertainty on the trend. Our analysis shows that a long time series of in situ profile measurements of trace gases such as SF6 and CO2 can be a unique and useful indicator of stratospheric circulation variability on a range of time scales and an important contributor to help validate the stratospheric portion of global chemistry climate models. However, with only SF6 and CO2 measurements, the competing effects on mean age between mean circulation and mixing (tropical entrainment) are not uniquely separable.
Key Points
Refined calculation of stratospheric mean age of air trendsMean ages have decreased in the lower stratosphere and increased in the middle stratosphereTrace gas measurements are a useful indicator of stratosphere circulation changes
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•The reactions of an iron atom with oxygen molecules are studied by the DFT method.•Potential energy surfaces are calculated for the Fe+O2 and FeO2+O2 reactions.•In our calculations ...the reactions of Fe with O2 are found to be endothermic.•The FeO2+O2 reactions endothermically produce the η2-(O2)FeO2 and η1-(O2)FeO2.•Optimized structure, vibrational and NBO analyses for products are reported.
The reactions of Fe and FeO2 with O2 and the products of these reactions are investigated at the B3LYP/6-311+G(d) level. The reactions are considered in terms of the calculated potential energy surfaces, the interaction energies between reactant species, and the energies required to populate the higher electronic states such as the excited states of Fe(5F, 3F) and O2(1Σg+). It is found that the reactions of Fe with O2 are endothermic and that the direct formation of dioxide OFeO is due to an ionic interaction of Fe+ with O2−. Furthermore, the diabatic transitions from the covalent and ionic surfaces onto another ionic surface with energy barriers allow the Fe+O2 reaction to proceed toward the formation of dioxide OFeO. There are other paths corresponding to the vertical excitation from peroxide Fe(O2) to dioxide OFeO; these require excitation energies above 23, 34, and 48kcalmol−1 in the low-lying triplet, quintet, and septet states, respectively. The OFeO+O2 reactions are found to endothermically produce the η2-(O2)FeO2 and η1-(O2)FeO2 complexes, and the low-lying states of complexes are found to be closely located in the energy range of 5.6kcalmol−1. The conversion of the η2-complex to the η1-complex and vice versa is caused by low energy. The NBO analyses show that the large atomic charges of peroxide Fe(O2), superoxide FeOO, and the η2- and η1-complexes are caused by electron transfer between reactant species, whereas those of dioxide OFeO are dominated by the ionic character of the species.
Silk fibroin (SF) possesses several characteristics that are favorable for tissue engineering. However, the mechanical properties must be modified in some cases. For instance, soft tissues such as ...those of the circulatory system are more elastic than tissue-engineered materials. The development of polymer blends is a simple method with the potential to provide materials with extended useful properties. In this study, we developed a non-woven SF and thermoplastic polyurethane-blend sheet from a polymer solution. The structure and miscibility of the blend sheet was evaluated using solid-state nuclear magnetic resonance (NMR) methods. In the 13 C cross-polarization and magic angle spinning NMR spectra, no peak shift was observed between the pure and blended samples. The miscibility of the sample was investigated using proton spin-lattice relaxation times in the laboratory frame (T1 H ). The T1 H measurement clearly revealed that the molecular chains of SF and Pellethane exist in close proximity of several tens of nanometers.
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