The earliest fossil record of animal biomineralization occurs in the latest Ediacaran Period (c. 550 Ma). Cloudina and Sinotubulites are two important tubular taxa among these earliest skeletal ...fossils. The evolutionary fate of Cloudina-type fossils across the Ediacaran–Cambrian transition, however, remains poorly understood. Here we report a multi-layered tubular microfossil Feiyanella manica gen. et sp. nov. from a phosphorite interval of the lowest Cambrian Kuanchuanpu Formation, southern Shaanxi Province, South China. This newly discovered fossil is a conical tube with a ‘funnel-in-funnel’ construction, showing profound morphological similarities to Cloudina and Conotubus. On the other hand, the outer few layers, and particularly the outermost layer, of Feiyanella tubes are regularly to irregularly corrugated, a feature strikingly similar to the variably folded/wrinkled tube walls of Sinotubulites. The Feiyanella tubes additionally exhibit two orders of dichotomous branching, similar to branching structures reported occasionally in Cloudina and possibly indicative of asexual reproduction. Owing to broad similarities in tube morphology, tube wall construction and features presumably indicative of asexual reproduction, Cloudina, Conotubus, Sinotubulites and the here described Feiyanella may thus constitute a monophyletic group traversing the Ediacaran–Cambrian boundary. The tube construction and palaeoecological strategy of Feiyanella putatively indicate evolutionary continuity in morphology and palaeoecology of benthic metazoan communities across the Ediacaran–Cambrian transition.
Nonvolatile memories based on van der Waals heterostructures have been proved to be promising candidates for next‐generation data storage devices. However, little attention has been focused on the ...structure with separated floating and control gates (the floating gates and control gates distribute at the different side of the channels), which were recently predicted to be capable of further improving device performance. Here, nonvolatile multibit optoelectronic memories are demonstrated using MoS2, hexagonal boron nitride (h‐BN), and graphene in a top‐floating‐gated structure. With separated top graphene floating gate, the devices show a large memory window (≈95 V) via sweeping gate voltage from 80 to −80 V, a high on/off ratio (≈106) with an ultralow dark current (≈10−14 A), as well as excellent retention characteristic (≈104 s) and cyclic endurance. In addition, these devices can also be erased by a laser illumination with broadband spectrum after being electrically programmed. For the multilevel storage property, 7/6 stages controlled by different electrical operations, and 13/6/3 stages by different laser pulse illuminations are gained. The obtained results show a promising performance for nonvolatile optoelectronic memory using a top‐floating‐gated structure.
A nonvolatile multibit optoelectronic memory in top‐floating‐gated van der Waals heterostructures is demonstrated. The fabricated device exhibits excellent electrical and optoelectrical memory performance, including large memory windows (95 V), a high on/off ratio (106), excellent retention (104), and multibit storage (7/6 for the electrical operation, 13/6/3 for the optical operation).
•Both the actual and theoretical growing seasons are lengthening in Northeast China.•Adjusting the sowing dates decreased the unutilized thermal time (TT) before sowing.•Cultivar selection increased ...the utilized TT and decreased the unutilized TT after maturity.•The increased grain yield by adjusting sowing dates far less than by switching to late maturing cultivars.•If the currently unutilized TT were fully explored, the local spring maize grain yield would have increased by 12.0–38.4%.
Global warming has lengthened the theoretical growing season of spring maize in Northeast China (NEC), and the temperatures during the growing season have increased. In practise, crop producers adjust sowing dates and alternate crop cultivars to take advantage of the lengthening growing season and increasing temperatures. In this study, we used crop data and daily weather data for 1981–2007 at five locations in NEC to quantify the utilization of the lengthening growing season and increasing temperatures by adjusting sowing dates and cultivar selection for spring maize production. If these two positive factors are not fully utilized, then it is important to know the potential impacts of these climatic trends on spring maize grain yields. The results show that in NEC, both the actual and theoretical growing seasons are lengthening, i.e., the sowing dates have been advanced and the maturity dates have been delayed. The actual sowing dates are 1–8days later and the actual maturity dates are 6–22days earlier than the theoretical perspective. Advancing sowing dates and changing cultivars led to 0–5days and 6–26days extension of the growing season. For the potential thermal time (TT), adjusting the sowing dates decreased the unutilized TT before sowing, while the cultivar selection increased the utilized TT and decreased the unutilized TT after maturity. On average, the unutilized heating resource before sowing is less than that after the maturity date (0.3–1.9% vs. 2.1–7.8%). During 1981–2007, for per day extension of the growing season, the spring maize grain yield increased by 75.2kgha−1. The spring maize grain yields have increased by 7.1–57.2% when both early sowing and changing cultivars during 1981–2007. In particular, adjusting the sowing dates increased the grain yield by 1.1–7.3%, which was far less than the increase effect (6.5–43.7%) from switching to late maturing cultivars. Therefore, selecting late maturing cultivars is an important technique to improve maize grain yields in NEC under the global warming context. Nevertheless, if the currently unutilized TT were fully explored, the local spring maize grain yield would have increased by 12.0–38.4%.
Vitamin D plays a critical role in calcium and phosphate metabolism and helps maintain skeletal integrity in childhood, yet vitamin D status in Chinese children and adolescents is not well ...documented. The aim of this study was to assess the vitamin D status and analyze the risk factors for vitamin D deficiency in Chinese children and adolescents aged 6-17 years. Serum 25 hydroxyvitamin D (25(OH)D) was measured with a radioimmunoassay kit in 15,000 children and adolescent participants in the Chinese national nutrition and health survey (CNNHS) 2010-2012. Age, gender, region type, ethnicity, outdoor time, and vitamin D supplementation were recorded in unified design questionnaires. The season was recorded by the date of blood taken; location was divided into north and south by China's Qinling Mountains and Huaihe River; and ambient ultraviolet B (UVB) radiation level was classified according to the corresponding dose of each participant living area from National Aeronautics and Space Administration data. 14,473 participants from the cross-sectional study of CNNHS 2010-2012 were included in this study. The median serum 25(OH)D concentration was 48.2 (35.4-63.4) nmol/L, and the concentration for males was 50.0 (36.5-65.7) nmol/L, which was statistically higher than that of females (46.7 (34.4-60.9) nmol/L) (
< 0.001). The general prevalence of vitamin D deficiency was 53.2%; 50.0% for males and 56.5% for females at the cut-off 50 nmol/L. According to the results of the log-binomial regression analysis, vitamin D deficiency in Chinese children and adolescents was specifically related to female gender (
< 0.0001), to ages 12-14 years (
< 0.0001) and 15-17 years (
< 0.0001), living in large cities (
< 0.0001) or ordinary rural areas (
< 0.0001), low ambient UVB levels (
< 0.0001) and medium ambient UVB levels (
< 0.0001), spring (
< 0.0001), autumn (
< 0.0001) and winter seasons (
< 0.0001). The data showed that vitamin D deficiency was very common among children and adolescents aged 6-17 years in China. Effective sun exposure should be encouraged in both genders aged 6-17 years, dietary vitamin D and vitamin D supplements are also recommended, especially in the seasons of spring and winter.
An optically rough and physically flat (OR-PF) TCO substrate was developed by spin-coating Al-doped ZnO thin film on glass substrate patterned with random pyramidal morphology to enhance the light ...absorption in superstrate-type thin-film silicon solar cells without deteriorating the growth of photoactive layers. This substrate possesses flat surface with a root mean square roughness of 10.9 nm, high visible light transmittance of over 86%, a sheet resistance of 29.5 Ω/sq, and moderate light-scattering ability. A surface morphology of random pyramidal morphology was formed on the glass substrate by replicating the pyramidal surface texture of a ZnO thin film with the room-temperature nanoimprint technique. Employed as the front electrode of hydrogenated amorphous Si single-junction solar cells, this OR-PF substrate enabled a Voc of 0.91 eV, an FF of 0.71, a Jsc gain of approximately 8%, and an efficiency gain of approximately 20% with respect to the AZO-coated flat glass substrate. The Jsc gain is attributed to the enhancement in the light absorption of a-Si:H solar cells triggered by the diffraction behaviour of the interfacial pyramidal morphology, while the achievement of large Voc and FF is ascribed to the improvement in the growth quality of the photoactive layers. Based on the calculation results of the bidirectional scattering distribution function, this substrate empowers comparable intensity of the diffraction peaks for 600–700 nm wavelength light but scatters less light away from the specular direction with respect to the conventional pyramid-textured ZnO substrate. This OR-PF substrate would enable efficient photon management and the growth of high-quality photoactive materials simultaneously for thin-film silicon solar cells.
•Sol-gel ZnO:Al coating on pyramid-patterned glass created a novel TCO substrate.•It possessed high transmittance, low surface roughness and light-scattering ability.•It enabled a-Si:H solar cells with a Voc of 0.91 V and an FF of 0.71.•A Jsc gain of 8% and an energy-conversion efficiency gain of 20% were achieved.
This study assessed the effect of Qianhu (
Peucedanum praeruptorum
Dunn
)
on the recovery of movement in mice with D-galactose-induced dyskinesia. The evaluation of the ability of mice to exercise ...revealed that Qianhu increased the running and swimming time to exhaustion in mice with dyskinesia. In addition, measurement of biochemical indices in mice showed that Qianhu altered the serum levels of blood urea nitrogen (BUN), blood lactic acid (BLA), malonaldehyde (MDA), liver glycogen (HG), muscle glycogen (MG), while the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) remained normal. Additionally, Qianhu regulated the mRNA expression of copper/zinc-superoxide dismutase (Cu/Zn-SOD), manganese-superoxide dismutase (Mn-SOD), catalase (CAT), heme oxygenase 1(HO-1), nuclear factor erythroid2-related factor (Nrf2) and syncytin-1 in mice and also protected mice against D-galactose-induced oxidative stress. The analysis of the chemical composition of Qianhu revealed that it mainly contains isochlorogenic acid B, myricetin, baicalin, luteolin, and kaempferol, which are known excellent antioxidants that protect against tissue damage due to oxidative stress and have anti-aging properties. Thus, these compounds may be the active components in Qianhu that improve the ability of mice to exercise, and may also represent the key compounds for its use as natural medicine or health food.
Accurate mathematical models, to describe and analyze complex systems, cannot be established. This is especially true for biological complex systems because of the complexity of interaction among ...constituent units inside the whole system. Descriptor biological complex systems are a new research field in descriptor systems; there has been little research about passivity and optimal control of descriptor biological complex systems. Passivity analysis and feedback controller design of the system offers an important basis for the research of descriptor system theory applied to biological complex systems. In this paper, a poly-chamber model of the endocrine disruptor - Diethylstibestrol - moving in a human body is developed based on physiological rules. Passivity of this model is described and proved systematically. A feedback controller for this descriptor biological complex system is designed under the station of strict passivity, and an example of the controller is given for a particular instantiation of the model.
The spread and resonance of users’ opinions on Sina Weibo, the most popular micro-blogging website in China, are tremendously influential, having significantly affected the processes of many ...real-world hot social events. We select 21 hot events that were widely discussed on Sina Weibo in 2011, and do some statistical analyses. Our main findings are that (i) male users are more likely to be involved, (ii) messages that contain pictures and those posted by verified users are more likely to be reposted, while those with URLs are less likely, (iii) the gender factor, for most events, presents no significant difference in reposting likelihood.
•Male users are more likely to talk about hot social events.•Picture-containing weibos are more likely to be reposted.•URL-containing weibos are less likely to be reposted.•Weibos posted by verified users are more likely to be reposted.
Climatic or technological ceilings could cause yield stagnation. Thus, identifying the principal reasons for yield stagnation within the context of the local climate and socio‐economic conditions are ...essential for informing regional agricultural policies. In this study, we identified the climatic and technological ceilings for seven rice‐production regions in China based on yield gaps and on a yield trend pattern analysis for the period 1980–2010. The results indicate that 54.9% of the counties sampled experienced yield stagnation since the 1980. The potential yield ceilings in northern and eastern China decreased to a greater extent than in other regions due to the accompanying climate effects of increases in temperature and decreases in radiation. This may be associated with yield stagnation and halt occurring in approximately 49.8–57.0% of the sampled counties in these areas. South‐western China exhibited a promising scope for yield improvement, showing the greatest yield gap (30.6%), whereas the yields were stagnant in 58.4% of the sampled counties. This finding suggests that efforts to overcome the technological ceiling must be given priority so that the available exploitable yield gap can be achieved. North‐eastern China, however, represents a noteworthy exception. In the north‐central area of this region, climate change has increased the yield potential ceiling, and this increase has been accompanied by the most rapid increase in actual yield: 1.02 ton ha⁻¹ per decade. Therefore, north‐eastern China shows a great potential for rice production, which is favoured by the current climate conditions and available technology level. Additional environmentally friendly economic incentives might be considered in this region.
In the present study, surface treatment techniques such as room temperature machining (RTM) and low temperature burnishing (LTB) processing have been used to improve the microstructure of GH738 ...superalloy. Nano-grains and nano-twins are obtained on the top surface of RTM and LTB specimens. It is found that although the grain size of RTM and LTB specimens is almost the same, different types of nano-twins have been produced. Moreover, the effect of RTM and LTB processing on high temperature oxidation behavior of nickel-based superalloy GH738 at 700 °C is investigated. The result shows that LTB specimen has the best high temperature oxidation resistance owing to the formation of nano-grains and higher twins density, which induce to form a continuous protective Al2O3 layer at the interface between outer oxide layer and matrix. It is observed that this layer inhibits the inward diffusion of O and outward diffusion of Ti and significantly improves oxidation resistance of LTB specimen. Furthermore, the effects of nano-grains and crystal defects on the diffusion mechanism of elements are clarified during the high temperature oxidation test.
PDF
