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Lower-crust-derived adakitic rocks in the Gangdese belt provide important constraints on the timing of Tibetan crustal thickening and on the relative contributions of magmatic and tectonic processes. Here we present geochronological and geochemical data for the Wangdui porphyritic monzogranites in the western Gangdese belt. Zircon U–Pb dating yields emplacement ages of 46–44 Ma. All samples have high Sr (321–599 ppm), low Yb (0.76–1.33 ppm) and Y (10.6–18.3 ppm) contents, with high La/Yb (51.1–72.3) and Sr/Y (21.0–51.4) ratios, indicating adakitic affinities. The low MgO (0.97–1.76 wt %), Cr (7.49–53.6 ppm) and Ni (4.75–29.1 ppm) contents, as well as high 87Sr/86Sr(i) (0.7143–0.7145), low ϵNd(t) (−10.4 to −9.8) and zircon ϵHf(t) (−17.7 to 0.4) values, suggest that the Wangdui pluton most likely originated from partial melting of the thickened ancient lower crust. In combination with previously published data, despite the east–west-trending heterogeneity of crustal composition in the Gangdese belt, the La/Yb ratios of magmatic rocks reveal that both western and eastern segments experienced remarkable crustal thickening in the Eocene. However, in contrast to the thickened juvenile lower crust in the eastern segment formed by the underplating of mantle-derived magmas, tectonic shortening plays a more crucial role in thickening of the ancient basement in western Gangdese. In fact, such Eocene-thickened ancient lower-crust-derived adakitic rocks are widely distributed in the central Himalayan–Tibetan orogen. This, together with the extensive development of fold–thrust belts, suggests that tectonic shortening might be the main mechanism accounting for the crustal thickening associated with the India–Asia collision.
Flutter suppression is an important measure to improve fatigue life and enhance the performance of aircraft in modern aircraft design. In order to design more effective controllers for flutter suppression with high efficiency, an efficient reduced-order framework for active/passive hybrid flutter suppression is proposed. The traditional CFD-based ROMs have been successfully applied to active flutter suppression with high accuracy and efficiency. But, when a structure modification is made such as in aeroelastic tailoring and aeroelastic structural optimisation, the structural model should be updated, and the expensive, time-consuming CFD-based ROMs have to be reconstructed; such a process is impractical for passive flutter suppression. To overcome the realistic challenge, an efficient reduced-order framework for active/passive hybrid flutter suppression is proposed by extending an efficient aeroelastic CFD-based POD/ROM which we have developed. The proposed framework is demonstrated and evaluated using an improved AGARD 445.6 wing model. The results show that the proposed framework can accurately predict the aeroelastic response for active/passive hybrid flutter suppression with high efficiency. It provides a powerful tool for active/passive hybrid flutter suppression, and therefore, is ideally suited to design more effective controllers, and may have the potential to reduce the overall cost of aircraft design.
The current study used behavioural and electroencephalograph measures to compare the transferability of three home-based interventions — cognitive training (CT), neurofeedback training (NFT), and CT combined with NFT — for reducing symptoms in children with attention-deficit/hyperactivity disorder (AD/HD). Following a multiple-baseline single-case experimental design, twelve children were randomised to a training condition. Each child completed a baseline phase, followed by an intervention phase. The intervention phase consisted of 20 sessions of at-home training. Tau-U analysis and standardised visual analysis were adopted to detect effects. Results showed that CT improved inhibitory function and NFT improved alpha EEG activity and working memory. The combined condition, which was a reduced ‘dose’ of CT and NFT, did not show any improvements. The three conditions did not alleviate AD/HD symptoms. While CT and NFT may have transfer effects on executive functions, considering the lack of improvement in symptoms, this study does not support CT and NFT on their own as a treatment for children with AD/HD.
Detailed balance of a chemical reaction network can be defined in several different ways. Here we investigate the relationship among four types of detailed balance conditions: deterministic, stochastic, local, and zero-order local detailed balance. We show that the four types of detailed balance are equivalent when different reactions lead to different species changes and are not equivalent when some different reactions lead to the same species change. Under the condition of local detailed balance, we further show that the system has a global potential defined over the whole space, which plays a central role in the large deviation theory and the Freidlin–Wentzell-type metastability theory of chemical reaction networks. Finally, we provide a new sufficient condition for stochastic detailed balance, which is applied to construct a class of high-dimensional chemical reaction networks that both satisfies stochastic detailed balance and displays multistability.
In this paper, we present results from an experiment using EEG to measure brain activity and explore EEG frequency power associated with gender differences of professional industrial designers while performing two prototypical stages of constrained and open design tasks, problem-solving and design sketching. Results indicate no main effect of gender. However, among other main effects, a consistent main effect of hemisphere for the six frequency bands under analysis was found. In the problem-solving stage, male designers show higher alpha and beta bands in channels of the prefrontal cortices and female designers in the right occipitotemporal cortex and secondary visual cortices. In the design sketching stage, male designers show higher alpha and beta bands in the right prefrontal cortex, and female designers in the right temporal cortex and left prefrontal cortex, where higher theta is also found. Prioritising different cognitive functions seem to play a role in each gender's approach to constrained and open design tasks. Results can be useful to design professionals, students and design educators, and for the development of methodological approaches in design research and education.
Creativity is crucial in design. In recent years, growing computational methods are applied to improve the creativity of design. This paper aims to explore an approach to generate creative design images with specific feature or design style. A Generative Adversarial Network model is applied in the approach to learn the specific design style. The target products will be projected into the latent space of model to transfer their styles and generate images. The generated images combine the features of the specific design style and the features of the target product. In the experiment, the approach using the generated images to inspire the human designer to generate the creative design in according styles. According to the primary verification by participants, the generated images can bring novelty and surprise to participants, which gain the positive impact on human creativity.
Subglacial lake exploration is of great interest to the science community. RECoverable Autonomous Sonde (RECAS) provides an exploration tool to measure and sample subglacial lake environments while the subglacial lake remains isolated from the glacier surface and atmosphere. This paper presents an electronic control system design of 200 m prototype of RECAS. The proposed electronic control system consists of a surface system, a downhole control system, and a power transfer and communication system. The downhole control system is the core element of RECAS, and is responsible for sonde status monitoring, sonde motion control, subglacial water sampling and in situ analysis. A custom RS485 temperature sensor was developed to cater for the limited size and depth requirements of the system. We adopted a humidity-based measurement to monitor for a housing leak. This condition is because standard leak detection monitoring of water conductivity may be inapplicable to pure ice in Antarctica. A water sampler control board was designed to control the samplers and monitor the on/off state. A high-definition camera system with built-in storage and self-heating ability was designed to perform the video recording in the subglacial lake. The proposed electronic control system is proven effective after a series of tests.
A series of new synthetic armored cables were developed and tested to ensure that they were suitable for use with the RECoverable Autonomous Sonde (RECAS), which is a newly designed freezing-in thermal ice probe. The final version of the cable consists of two concentric conductors that can be used as the power and signal lines. Two polyfluoroalkoxy jackets are used for electrical insulation (one for insulation between conductors, and the other for insulation of the outer conductor). The outer insulation layer is coated by polyurethane jacket to seal the connections between the cable and electrical units. The 0.65 mm thick strength member is made from aramid fibers woven together. To hold these aramid fibers in place, a sheathing layer was produced from a polyamide fabric cover net. The outer diameter of the final version of the cable is ~6.1 mm. The permissible bending radius is as low as 17–20 mm. The maximal breaking force under straight tension is ~12.2 kN. The cable weight is only ~0.061 kg m−1. The mechanical and electrical properties and environmental suitability of the cable were determined through laboratory testing and joint testing with the probe.
Early diagnosis and treatment of depression are associated with better prognosis. We used baseline data of the Canadian Longitudinal Study on Aging (2012–2015; ages 45–85 years) to examine differences in prevalence and predictors of undiagnosed depression (UD) between immigrants and non-immigrants at baseline and persistent and/or emerging depressive symptoms (DS) 18 months later. At this second time point, we also examined if a mental health care professional (MHCP) had been consulted.
We excluded individuals with any prior mood disorder and/or current anti-depressive medication use at baseline. UD was defined as the Center for Epidemiological Studies Depression 10 score ⩾10. DS at 18 months were defined as Kessler 10 score ⩾19. The associations of interest were examined in multivariate logistic regression models.
Our study included 4382 immigrants and 18 620 non-immigrants. The mean age (standard deviation) in immigrants was 63 (10.3) years v. 65 (10.7) years in non-immigrants and 52.1% v. 57.1% were male. Among immigrants, 12.2% had UD at baseline of whom 34.2% had persistent DS 18 months later v. 10.6% and 31.4%, respectively, among non-immigrants. Female immigrants were more likely to have UD than female non-immigrants (odds ratio 1.50, 95% confidence interval 1.25–1.80) but no difference observed for men. The risk of persistent DS and consulting an MHCP at 18 months did not differ between immigrants and non-immigrants.
Female immigrants may particularly benefit from depression screening. Seeking mental health care in the context of DS should be encouraged.
The Antarctic subglacial drilling rig (ASDR) is designed to recover 105 mm-diameter ice cores up to 1400 m depth and 41.5 mm-diameter bedrock cores up to 2 m in length. In order to ensure safe and convenient drilling, drilling auxiliaries are designed to support fieldwork and servicing. These auxiliaries are subdivided into several systems for power supply, drill tripping in the borehole, ice core and chip processing, and drill servicing and maintenance. The required equipment also includes two generators, a drilling winch with a cable, logging winch with a cable, control desk, pipe handler with a fixed clamp, chip chamber vibrator, centrifuge, emergency devices and fitting and electrical tools. Additionally, several environmental protective measures such as a new liquid-tight casing with a thermal casing shoe and a bailing device for recovering drilling fluid from the borehole were designed. Most of the auxiliaries were tested during the summer of 2018–2019 near Zhongshan Station, East Antarctica while drilling to the bedrock to a depth of 198 m.
Drilling to the bedrock of ice sheets and glaciers offers unique opportunities for examining the processes occurring in the bed. Basal and subglacial materials contain important paleoclimatic and paleoenvironmental records and provide a unique habitat for life; they offer significant information regarding the sediment deformation beneath glaciers and its effects on the subglacial hydraulic system and geology. The newly developed and tested Antarctic subglacial drilling rig (ASDR) is designed to recover ice and bedrock core samples from depths of up to 1400 m. All of the drilling equipment is installed inside a movable, sledge-mounted, temperature-controlled and wind-protected drilling shelter and workshop. To facilitate helicopter unloading of the research vessel, the shelter and workshop can be disassembled, with individual parts weighing <2–3 tons. The entire ASDR system weighs ~55 tons, including transport packaging. The ASDR is designed to be transported to the chosen site via snow vehicles and would be ready for drilling operations within 2–3 d after arrival. The ASDR was tested during the 2018–2019 summer season near Zhongshan Station, East Antarctica. At the test site, 2-week drilling operations resulted in a borehole that reached bedrock at a depth of 198 m.
Most skarns are found near the pluton or in lithologies containing at least some limestone. However, recent research has shown that neither a pluton nor limestone is necessarily required to form a skarn deposit. The newly discovered Bagenheigeqier Pb–Zn skarn deposit is located in NE China. The skarn and Pb–Zn orebodies occur in volcanic lithologies of the Baiyin’gaolao Formation and are controlled by NE–SW-trending faults. The nearest pluton is a granite porphyry, at a distance of 20–250 m from the orebodies. Five paragenetic stages at Bagenheigeqier are recognized: (I) skarn; (II) oxide; (III) early sulphide; (IV) late sulphide; and (V) late quartz–calcite. The fluid inclusions from stages II to V homogenized at temperatures of 402–452, 360–408, 274–319 and 167–212°C, respectively. The hydrogen and oxygen isotope compositions (δ18OH2O, –12.4‰ to +9.3‰; δDH2O, –156.5‰ to –99.1‰) indicate that the ore-fluids were primarily of magmatic origin, with the proportion of meteoric water increasing during the progression of ore formation. Sulphur isotope values (δ34SVCDT, 1.4–5.5‰), lead isotope values (206Pb/204Pb, 18.184–18.717; 207Pb/204Pb, 15.520–15.875; 208Pb/204Pb, 37.991–38.379) and the initial 187Os/188Os ratios of the pyrite (0.307 ± 0.06) suggest that the ore metals were derived from the granite porphyry and Baiyin’gaolao Formation. Re–Os dating of pyrite intergrown with galena and sphalerite yielded a well-constrained isochron age of 151.2 ± 4.7 Ma, which is coeval with the laser ablation – inductively coupled plasma – mass spectrometry zircon U–Pb age of 154 ± 1 Ma for the granite porphyry. The deposit was therefore formed during Late Jurassic time.
A new, modified version of the cable-suspended Ice and Bedrock Electromechanical Drill (IBED) was designed for drilling in firn, ice, debris-rich ice and rock. The upper part of the drill is almost the same for all drill variants and comprises four sections: cable termination, a slip-ring section, an antitorque system and an electronic pressure chamber. The lower part of the IBED comprises an auger core barrel, reamers, a core barrel for ice/debris-ice drilling and a conventional geological single-tube core barrel or custom-made double-tube core barrel. First, the short and full-scale field versions of the IBED were tested at an outdoor testing stand and a testing facility with a 12.5 m-deep ice well. Then, in the 2018–2019 summer season, the IBED was tested in the field at a site ~12 km south of Zhongshan Station, East Antarctica, and a ~6 cm bedrock core was recovered from a 198 m-deep borehole. A total of 18 d was required to penetrate the ice sheet. The retrieved core samples of blue ice, basal ice and bedrock provided valuable information regarding the Earth's paleo-environment.
In many cases, the efficiency and safety of a drilling project depend on the reliability of the electrical and electronic control system, as the process progresses without visual access of the operator. The electrical and electronic system provides and regulates the power supply for the drill, collects and monitors the drill data during the whole operating process, and sends and receives the control instructions and feedback signals. The entire system is composed of the surface, borehole and software subsystems. The surface subsystem serves for operating the drilling process, transmitting the drilling and environmental data, and supplying power for the drill motor and downhole control system. The borehole subsystem is generally intended for borehole data acquisition, drill motor control, power regulation and communication. The software subsystem is designed for human–computer interaction, data processing and storage, and programming of signal acquisition and transmission of data. The control system of Antarctic subglacial drilling rig was tested during the 2018–2019 summer season near Zhongshan Station, East Antarctica, in the course of drilling to the bedrock at a depth of 198 m. It exhibited a steady and efficient performance without significant system failures.
Multiple sulphur isotope compositions of sedimentary pyrites across the Ediacaran–Cambrian (Ed–C) transition and into the early Cambrian from the Xiaotan section, Yunnan, South China, are presented to explore the evolution of the sulphur cycle. The values of δ34Spy range from 13.5 ‰ to 35.8 ‰, and the values of Δ33Spy range from −0.044 ‰ to 0.063 ‰. The first-order observation of highly positive δ34Spy is consistent with sulphur isotope records from other sedimentary successions (with various degrees of enrichment in 34S), reflecting a common feature in cycling of sulphur among ocean basins. The positive values suggest that pyrite was formed in a depositional setting with limiting availability of sulphate that suppressed the expression of microbial fractionations. The first-order observation of a 10-million-year period of negative Δ33Spy beginning around the Ed–C boundary likely reflects changes in isotopic compositions of sulphur influx to the oceans. Such changes are suggested to be linked to a pulse of preferred weathering of sulphides (with negative Δ33S) relative to sulphate, which may reflect enhanced exposure of pyrites in continental margins due to reorganization of continents at this time. Both δ34Spy and Δ33Spy data imply low seawater sulphate levels, and possibly heterogeneity in sulphate concentrations in the world’s coastal oceans. The predictions about sulphur isotope signatures of evolved seawater (with highly positive δ34S and negative Δ33S) at the Xiaotan section are testable with future measurements of carbonate-associated sulphate (CAS), a proxy of ancient oceanic sulphate that carries information about the operation of sulphur cycling on a global scale.
Mineral particles in bone are interlaced with collagen fibrils, hindering the investigation of bioapatite crystallites (BAp). This study utilized a special whale rostrum (the most highly mineralized bone ever recorded) to measure the crystallites of bone BAp via long-term dissolution in water. The BAp in the rostrum has a low solubility (6.7 ppm Ca and 3.8 ppm P after 150 days dissolution) as well as in normal bones, which leads to its Ksp value of ~10−53. Atomic force microscopy results show tightly compacted mineral crystallites and confirm the low amount of collagen in the rostrum. Additionally, the mineral crystallites demonstrate irregular plate-like shapes with variable sizes. The small crystallites (~11 × 24 nm) are easily detached from BAp prisms, compared with the large crystallites (~50 nm). Moreover, various orientations of crystallites are observed on the edge of the prisms, which suggest a random direction of mineral growth. Furthermore, these plate-like crystallites prefer to be stacked layer by layer under weak regulation from collagen. The morphology of rostrum after dissolution provides new insights into the actual morphology of BAp crystallites.
We present the second data release (DR2) of the SkyMapper Southern Survey, a hemispheric survey carried out with the SkyMapper Telescope at Siding Spring Observatory in Australia, using six optical filters: u, v, g, r, i, z. DR2 is the first release to go beyond the
) limit of the Shallow Survey released in the first data release (DR1), and includes portions of the sky at full survey depth that reach
mag in g and r filters. The DR2 photometry has a precision as measured by internal reproducibility of 1% in u and v, and 0.7% in griz. More than 21 000
have data in some filters (at either Shallow or Main Survey depth) and over 7 000
have deep Main Survey coverage in all six filters. Finally, about 18 000
have Main Survey data in i and z filters, albeit not yet at full depth. The release contains over 120 000 images, as well as catalogues with over 500 million unique astrophysical objects and nearly 5 billion individual detections. It also contains cross-matches with a range of external catalogues such as Gaia DR2, Pan-STARRS1 DR1, GALEX GUVcat, 2MASS, and AllWISE, as well as spectroscopic surveys such as 2MRS, GALAH, 6dFGS, and 2dFLenS.