Hydroxyl (OH) radical reactivity (k(OH)) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Julich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapour, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements (limit of detection < 1 s(-1) at a time resolution of 30 s to a few minutes) is higher for instruments directly detecting hydroxyl radicals, whereas the indirect comparative reactivity method (CRM) has a higher limit of detection of 2 s(-1) at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapour or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected into the chamber to simulate urban and forested environments. Overall, the results show that the instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to reference measurements or to calculated reactivity were observed by CRM instruments in the presence of terpenes and oxygenated organic compounds (mixing ratio of OH reactants were up to 10 ppbv). In some of these experiments, only a small fraction of the reactivity is detected. The accuracy of CRM measurements is most likely limited by the corrections that need to be applied to account for known effects of, for example, deviations from pseudo first-order conditions, nitrogen oxides or water vapour on the measurement. Methods used to derive these corrections vary among the different CRM instruments. Measurements taken with a flow-tube instrument combined with the direct detection of OH by chemical ionisation mass spectrometry (CIMS) show limitations in cases of high reactivity and high NO concentrations but were accurate for low reactivity (< 15 s(-1)) and low NO (< 5 ppbv) conditions.
The broad applicability of super-resolution microscopy has been widely demonstrated in various areas and disciplines. The optimization and improvement of algorithms used in super-resolution microscopy are of great importance for achieving optimal quality of super-resolution imaging. In this review, we comprehensively discuss the computational methods in different types of super-resolution microscopy, including deconvolution microscopy, polarization-based super-resolution microscopy, structured illumination microscopy, image scanning microscopy, super-resolution optical fluctuation imaging microscopy, single-molecule localization microscopy, Bayesian super-resolution microscopy, stimulated emission depletion microscopy, and translation microscopy. The development of novel computational methods would greatly benefit super-resolution microscopy and lead to better resolution, improved accuracy, and faster image processing.
The brain integrates discrete but collinear stimuli to perceive global contours. Previous contour integration (CI) studies mainly focus on integration over space, and CI is attributed to either V1 long-range connections or contour processing in high-visual areas that top-down modulate V1 responses. Here, we show that CI also occurs over time in a design that minimizes the roles of V1 long-range interactions. We use tilted contours embedded in random orientation noise and moving horizontally behind a fixed vertical slit. Individual contour elements traveling up/down within the slit would be encoded over time by parallel, rather than aligned, V1 neurons. However, we find robust contour detection even when the slit permits only one viewable contour element. Similar to CI over space, CI over time also obeys the rule of collinearity. fMRI evidence shows that while CI over space engages visual areas as early as V1, CI over time mainly engages higher dorsal and ventral visual areas involved in shape processing, as well as posterior parietal regions involved in visual memory that can represent the orientation of temporally integrated contours. These results suggest at least partially dissociable mechanisms for implementing the Gestalt rule of continuity in CI over space and time.
Long-term measurements of particle number size distributions in combination with thermodenuder analysis have been performed since July 2003 at the Central European station of Melpitz, Germany. Up to the end of 2011, 20% of all investigated days during the 8.5 years of measurements showed new particle formation and subsequent growth. To investigate the role of various chemical compound candidates for condensational nanoparticle growth, we focused on nucleation events in which the measured size distributions with and without thermodesorption both showed growth patterns (accounting for up to similar to 85% of all nucleation events). In this study, particulate compounds that volatilize at 300 degrees C were specifically defined as "volatile," in contrast to "nonvolatile" compounds, which remain in the particulate phase after being heated to 300 degrees C. A strong correlation between ambient temperature and growth rate associated with volatile substances (except gaseous sulfuric acid) was found, which implies the importance of organics (possibly oxidized biogenic organic compounds) in particle growth at Melpitz. The contributions of the volatile compounds to the growth rate due to condensation of gaseous sulfuric acid and organics were found to be about 19% and 47%, respectively. The remaining similar to 25% was attributed to nonvolatile residuals, which appear to form gradually during the particle growth process and are characterized as extremely low-volatility compounds. The growth rate associated with volatile components exhibited significant seasonal variation, with the highest value during summertime, whereas the growth rate associated with the nonvolatile fraction showed less fluctuation.
The industrial sector is a major source of China's major CO2 emissions. In 2012, the emissions embedded in the final-use-induced intermediate CO2 flows contributed to approximately 91.2% of the total emissions. Hence, controlling CO2 emissions along supply chains could have a significant contribution in achieving the climate mitigation goal to which the Chinese government has been committed. In this study, we first extracted final-use induced CO2 transfer networks from input-output tables, and then applied the power-of-pull approach to the networks to identify the key sectors significantly affecting the CO2 emissions of each targeted sector's supply chains. Our results showed that each sector itself has significant power of pulling their emissions. Energy and raw material providers have played an essential role in pulling other sectors' emissions in the past years. The results of all sectors can easily construct a network reflecting the system's characteristics. And the power-of-pull approach could easily be integrated with the structural path analysis. Our proposed approach has the potential in helping policy making by offering a new perspective.
On the cover: The cover image, by Yanmei Dou et al., is based on the Research Article Postzygotic single‐nucleotide mosaicisms contribute to the etiology of autism spectrum disorder and autistic traits and the origin of mutations, Pages 1002–1013. DOI 10.1002/humu. 23284
The firework algorithm (FWA) is a novel swarm intelligence-based method recently proposed for the optimization of multi-parameter, nonlinear functions. Numerical waveform inversion experiments using a synthetic model show that the FWA performs well in both solution quality and efficiency. We apply the FWA in this study to crustal velocity structure inversion using regional seismic waveform data of central Gansu on the northeastern margin of the Qinghai-Tibet plateau. Seismograms recorded from the moment magnitude (MW) 5.4 Minxian earthquake enable obtaining an average crustal velocity model for this region. We initially carried out a series of FWA robustness tests in regional waveform inversion at the same earthquake and station positions across the study region, inverting two velocity structure models, with and without a low-velocity crustal layer; the accuracy of our average inversion results and their standard deviations reveal the advantages of the FWA for the inversion of regional seismic waveforms. We applied the FWA across our study area using three component waveform data recorded by nine broadband permanent seismic stations with epicentral distances ranging between 146 and 437 km. These inversion results show that the average thickness of the crust in this region is 46.75 km, while thicknesses of the sedimentary layer, and the upper, middle, and lower crust are 3.15, 15.69, 13.08, and 14.83 km, respectively. Results also show that the P-wave velocities of these layers and the upper mantle are 4.47, 6.07, 6.12, 6.87, and 8.18 km/s, respectively.
We present high-precision chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-IDTIMS) U-Pb zircon and isotope dilution-negative-diennal ionization mass spectrometry (ID-N-TIMS) Re-Os molybdenite geochronology of the world class Tibetan Qulong porphyry Cu-NIo deposit. The data is used to constrain the timing, duration, and to yield implications for the ore -forming processes. The (-Pb data suggest that the preore Bonginuctiola pluton crystallized at 17.142 0.014/0.014/0.023 Ma (uncertainties presented as analytical /+ tracer /+ decay constant uncertainties), with emplacements of the synore P porphyry and postore quartz diorite occurring at 16.009 +/- 0.016/0.017/0.024 and 15.166 +/- 0.010/0.011/0.020 Ma, respectively. The Re-Os analysis of nudtiple independent molybdenite separations from single molybdenite-bearing quartz veins yields sub-%(0) level analytical precision (<1%(0)), which is comparable with that of modern CA[D-TINTSU-Pb zircon geochronology. The new Re-Os data indicate that the majority of the metals at Qulong were deposited over a minimum duration of 266 13 k.y., between 16.126 +/- 0.008/0.060/0.077 and 1.5.86 +/- 00.010/0.058/0.075 Ma, with die main phase of mineralization being broadly synchronous with the emplacement of die P porphyry. However, our Re-Os data of molybdenite hosted within the Rongmuctiola pillion imply that a portion of mineralizadon also predated die P porphyry and suggest that die P porphyry is an intermineral porphyry stock, although mineralization cut by P porphyry has not been previously documented or observed in this study. Correlating the Re-Os ages with vein types (A-B-D veins) demonstrates that the mineralization process was cyclical, with the presence of at least three short-lived (38 +/- 11 to 59 10 k.y.) mineralization pulses between 16.1.26 +/- 0.008 and 16.050 +/- 0.005, 16.040 +/- 0.007 and 15.981 +/- 0.007, and similar to 15.981 +/- 0.007 and 15.860 +/- 0.010 Ma. Coupling die Re-Os molybdenite ages and quartz (coprecipitated with die dated molybdenite) fluid inclusion data suggests that die cooling history was also cyclic, and implies a rapid cooling rate during the entire mineralization process (0.55 degrees +/- 0.11 C/k.y.), with much faster cooling rates (1.19 degrees +/- 0.82 degrees to 1.27 degrees +/- 0.53 degrees C/k.y.) for the individual mineralization pulses. The cyclic and rapid cooling process requires an additional cooling mechanism rather than the inefficient conduction, which we attribute to meteoric water circulation.The presence of mineralization predating the intermineral P porphyry stock and the absence of evidence of an early porphyry stock at Qulong suggest that mineralization potentially can take place without contemporaneous magmatism at mineralization levels. As a result, dating magmatic events may not necessarily bracket the entire mineralization duration of a porphyry system. This highlights the importance of dating ore minerals to reveal a comprehensive picture of the magma-hydrothermal process. In addition, the absence of contemporaneous magmatism during mineralization has broad implications for the classification of porphyry copper deposits and mineral exploration. The timescales of mineralization cycles constrained here via direct dating of ore minerals (tens of k.y.) are comparable with those recently proposed through high -precision U-Pb zircon dating, diffusion modeling, and numerical simulation. We propose that the cyclic mineralization pulses are linked with the periodic release of volatiles from the lower crustal magma chamber, which are common for porphyry copper systems worldwide. The episodic/cyclic metal enrichment process potentially is one of the controlling factors of porphyry copper ore formation and is the key to differentiate the formation of economic and subeconomic porphyry deposits.Finally, direct comparison of molybdenite Re-Os dates from different laboratories and with the zircon U-Pb system needs to account for the much larger uncertainties from tracer calibration and decay constants, respectively. As a result, we lose the necessary resolution to investigate the ore -forming process at the k.y. level. Therefore, to reduce these uncertainties, calibration between the two chronometers, using shared tracer solutions and a transparent data reduction platform within the community is required.
Objective To examine whether previous observed inverse associations of dairy intake with systolic blood pressure and risk of hypertension were causal.Design Mendelian randomization study using the single nucleotide polymorphism rs4988235 related to lactase persistence as an instrumental variable.Setting CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium.Participants Data from 22 studies with 171 213 participants, and an additional 10 published prospective studies with 26 119 participants included in the observational analysis.Main outcome measures The instrumental variable estimation was conducted using the ratio of coefficients approach. Using meta-analysis, an additional eight published randomized clinical trials on the association of dairy consumption with systolic blood pressure were summarized.Results Compared with the CC genotype (CC is associated with complete lactase deficiency), the CT/TT genotype (TT is associated with lactose persistence, and CT is associated with certain lactase deficiency) of LCT-13910 (lactase persistence gene) rs4988235 was associated with higher dairy consumption (0.23 (about 55 g/day), 95% confidence interval 0.17 to 0.29) serving/day; P<0.001) and was not associated with systolic blood pressure (0.31, 95% confidence interval -0.05 to 0.68 mm Hg; P=0.09) or risk of hypertension (odds ratio 1.01, 95% confidence interval 0.97 to 1.05; P=0.27). Using LCT-13910 rs4988235 as the instrumental variable, genetically determined dairy consumption was not associated with systolic blood pressure (beta=1.35, 95% confidence interval -0.28 to 2.97 mm Hg for each serving/day) or risk of hypertension (odds ratio 1.04, 0.88 to 1.24). Moreover, meta-analysis of the published clinical trials showed that higher dairy intake has no significant effect on change in systolic blood pressure for interventions over one month to 12 months (intervention compared with control groups: beta=-0.21, 95% confidence interval -0.98 to 0.57 mm Hg). In observational analysis, each serving/day increase in dairy consumption was associated with -0.11 (95% confidence interval -0.20 to -0.02 mm Hg; P=0.02) lower systolic blood pressure but not risk of hypertension (odds ratio 0.98, 0.97 to 1.00; P=0.11).Conclusion The weak inverse association between dairy intake and systolic blood pressure in observational studies was not supported by a comprehensive instrumental variable analysis and systematic review of existing clinical trials.
