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Seasonal climate variability is an important component of Earth's climate system, and has a significant impact on ecosystems and social systems. However, the temporal resolution of most proxy-based paleoclimate records is limiting to fully understand the past seasonal changes. Here, we used high-precision monthly resolution Sr/Ca records of three Tridacna squamosa specimens from the northern South China Sea (SCS) to reconstruct the sea surface temperature (SST) seasonality during three time periods from the middle Holocene. The results suggested that SST seasonality in the northern SCS during the middle Holocene (3.21 ± 0.98°C) was smaller than that for recent decades (AD 1994–2004, 4.32 ± 0.59°C). Analysis of modern instrumental data showed that the SST seasonality in the northern SCS was dominated by the winter SST, which was deeply influenced by the intensity of East Asian winter monsoon (EAWM). A strong EAWM usually resulted in cooler winter SST and a larger SST seasonality in the northern SCS. The reconstructed Holocene EAWM records showed that the EAWM strengthened from the middle to late Holocene, which was seen in our reconstruction of less SST seasonality changes during the middle Holocene in the northern SCS. This study highlighted that the Sr/Ca ratios from Tridacna shells can be used as a potential high-resolution indicator of past seasonal climate changes.
This paper addresses fixed-time trajectory tracking for a dual-arm free-floating space robot (FFSR) with the large initial errors and bounded uncertainty. A wrist-based trajectory planning method is improved by fixed-time stability to fast eliminate the error caused by singularity. Then, a novel low-chattering and global-nonsingular fixed-time terminal sliding mode control strategy is studied by state approaching angle and switching sliding mode; the practical fixed-reachable Lyapunov stability analysis is presented for a mechanical control system. In the end, the proposed trajectory planning method and controller are combined to improve the tracking accuracy of end-effector to the nanoscale. Simulation results validate the effectiveness of the proposed methodologies.
This study was designed to investigate the effects of dietary starch structure on muscle protein synthesis and gastrointestinal amino acid (AA) transport and metabolism of goats. Twenty-seven Xiangdong black female goats (average body weight = 9.00 ± 1.12 kg) were randomly assigned to three treatments, i.e., fed a T1 (normal corn 100%, high amylose corn 0%), T2 (normal corn 50%, high amylose corn 50%) and T3 (normal corn 0%, high amylose corn 100%) diet for 35 days, respectively. All amino acids in the ileal mucosa were decreased linearly as amylose/amylopectin increased in diets (P<0.05). The plasma valine (linear, P=0.03), leucine (linear, P=0.04), and total amino acids content (linear, P=0.03) increased linearly with the increase in the ratio of amylose in the diet. The relative mRNA levels of SLC38A1 (linear, P=0.01), SLC3A2 (linear, P=0.02), and SLC38A9 (linear, P=0.02) in the ileum increased linearly with the increase in the ratio of amylose in the diet. With the increase in the ratio of amylose/amylopectin in the diet, the mRNA levels of ACADSB (linear, P=0.04), BCAT1 (linear, P=0.02), and BCKDHB (linear, P=0.01) in the ileum decreased linearly. Our results revealed that the protein abundances of p-mTOR (P<0.001), p-4EBP1 (P<0.001), and p-S6K1 (P<0.001) of T2 and T3 were significantly higher than that of T1. In general, a diet with a high amylose ratio could reduce the consumption of amino acids in the intestine, allowing more amino acids to enter the blood to maintain higher muscle protein synthesis through the mTOR pathway.
In nature, competing species often achieve coexistence through niche differentiation. We examined this phenomenon for Pachycrepoideus vindemmiae and Spalangia endius (Hymenoptera: Pteromalidae), two species of pupal parasitoids that are considered biological control agents of house fly, Musca domestica (Diptera: Muscidae). We examined the ability of each species, alone and in combination, to locate host pupae buried at different depths (0, 1, 2, 4, and 6 cm) in three types of substrate (sand, dry wheat bran, and spent fly diet). We then evaluated the competitiveness of each species by allowing first one species, then the other species, to parasitise host individuals within time periods ranging from less than 2 hours to 96 hours of each other. Spalangia endius exhibited greater ability than did P. vindemmiae to locate host pupae buried at depths below one centimetre. Conversely, P. vindemmiae exhibited a greater competitive ability, being more likely to emerge from pupae co-parasitised by S. endius, regardless of oviposition interval or sequence. Our findings suggest that these two parasitoid species coexist through niche differentiation. Our findings also indicate that to increase the effectiveness of biological control, the environmental conditions and risk of interspecific competition should be considered when selecting parasitoid species for release.
To examine the association between sleep duration in different stages of life and amnestic mild cognitive impairment (aMCI).
Design, setting, and participants:
A total of 2472 healthy elderly and 505 patients with aMCI in China were included in this study. The study analyzed the association between aMCI and sleep duration in different stages of life.
We compared sleep duration in different stages of life and analyzed the association between Montreal Cognitive Assessment scores and sleep duration by curve estimation. Logistic regression was used to evaluate the association between aMCI and sleep duration.
In the analysis, there were no results proving that sleep duration in youth (P = 0.719, sleep duration < 10 hours; P = 0.999, sleep duration ≥ 10 hours) or midlife (P = 0.898, sleep duration < 9 hours; P = 0.504, sleep duration ≥ 9 hours) had a significant association with aMCI. In the group sleeping less than 7 hours in late life, each hour more of sleep duration was associated with approximately 0.80 of the original risk of aMCI (P = 0.011, odds ratio = 0.80, 95% confidence interval = 0.68–0.95).
Among the elderly sleeping less than 7 hours, there is a decreased risk of aMCI for every additional hour of sleep.
X-ray powder diffraction data, unit-cell parameters, and space group for N,N-dimethyl-1H-benzo[d]imidazol-2-amine, C9H11N3, are reported [a = 11.379(3) Å, b = 10.227(5) Å, c = 7.151(1) Å, α = 90°, β = 90°, γ = 90°, unit-cell volume V = 832.318 Å3, Z = 4, ρcal = 1.286 g cm−3, and space group P21212]. All measured lines were indexed and were consistent with the P21212 space group. No detectable impurities were observed.
The theory of plate tectonics suggests that deformation occurs mainly along plate boundaries; however, compression can result in the formation of orogens and basins within intracontinental settings. During these two tectonic processes, the sedimentation and environmental changes occur in response to marginal and intracontinental deformation. Early Jurassic – Early Cretaceous deformation and basin formation along the Qinling orogenic belt and the northwestern Sichuan Basin in central–SW China are ideal for investigating a reactivated tectonic belt and basin formation. We studied the Lower Jurassic – Lower Cretaceous sedimentary sequences and structures along the northwestern margin of the Sichuan Basin, and obtained detrital zircon U–Pb ages for these rocks. The structures show that deformation migrated SE-wards and S-wards into the Sichuan Basin along the Longmen Shan, Micang Shan and Daba Shan tectonic belts during middle–late Mesozoic time. The Lower Jurassic oligomictic conglomerates have a smaller grain size and thicken towards the south, indicating protracted transport from a northern source. The conglomerates deposited near-source record post-orogenic south-vergent thrusting during the Late Triassic – Early Jurassic epochs. The Lower Cretaceous conglomerates and sandstones have multiple sources, which indicate that they were rapidly deposited near their source, synchronous with thrusting that occurred in response to coeval SE-wards and S-wards thrusting in the Longmen Shan and Daba Shan tectonic belts during the Late Jurassic – Early Cretaceous epochs. Detrital zircon grains from the Lower Jurassic – Lower Cretaceous sedimentary rocks yielded age peaks of 2600–2200, 1850–1600, 850–700, 540–400, 250–180 and 180–140 Ma. A comparison of these ages with those of surrounding exposed rocks indicates that the sediments in the northwestern Sichuan Basin were supplied from the Qinling orogenic belt, the northwestern Yangtze Block, the south margin of the North China Block and the Songpan–Garzê Terrane. The youngest peaks of detrital zircon U–Pb ages at 207 and 159 Ma constrain the two stages of intracontinental shortening and highlight the link between intracontinental deformation and sedimentation.
We theoretically and experimentally investigate the mechanism underlying the generation of upstream-propagating waves induced by a steady current over a horizontal bottom with a patch of sinusoidal ripples. By considering the triad resonant wave–ripple interactions involving two unsteady wave components (which have the same frequency but different wavenumbers) and one bottom ripple component in the presence of a steady uniform current, we derive the general condition under which unsteady upstream- and/or downstream-propagating waves can be induced. The frequency and wavenumbers of the induced propagating waves are given by the triad resonance condition in terms of current speed, water depth and bottom ripple wavenumber. By means of a multiple-scale perturbation analysis, we obtain the nonlinear amplitude evolution equations governing the spatio-temporal evolution of resonance-generated waves. Based on these equations, we find that the amplitude of the generated upstream-propagating waves is dramatically amplified when the associated triad resonance occurs in the neighbourhood of the critical current speed/frequency (corresponding to zero group velocity of unsteady waves in the presence of a current). A series of laboratory experiments in a long wave flume with wide ranges of current speeds and water depths are conducted to verify the theory. The experiments confirm the observation of the phenomenon of upstream-propagating wave generation in a steady flow over a rippled bottom. In particular, the experimental measurements of the kinematics of upstream-propagating waves as well as the critical flow condition for the observation of such wave generation compare well with the theoretical prediction.
This study proposed a novel ensemble analysis strategy to improve hand, foot and mouth disease (HFMD) prediction by integrating environmental data. The approach began by establishing a vector autoregressive model (VAR). Then, a dynamic Bayesian networks (DBN) model was used for variable selection of environmental factors. Finally, a VAR model with constraints (CVAR) was established for predicting the incidence of HFMD in Chengdu city from 2011 to 2017. DBN showed that temperature was related to HFMD at lags 1 and 2. Humidity, wind speed, sunshine, PM10, SO2 and NO2 were related to HFMD at lag 2. Compared with the autoregressive integrated moving average model with external variables (ARIMAX), the CVAR model had a higher coefficient of determination (R2, average difference: + 2.11%; t = 6.2051, P = 0.0003 < 0.05), a lower root mean-squared error (−24.88%; t = −5.2898, P = 0.0007 < 0.05) and a lower mean absolute percentage error (−16.69%; t = −4.3647, P = 0.0024 < 0.05). The accuracy of predicting the time-series shape was 88.16% for the CVAR model and 86.41% for ARIMAX. The CVAR model performed better in terms of variable selection, model interpretation and prediction. Therefore, it could be used by health authorities to identify potential HFMD outbreaks and develop disease control measures.
We aim to determine the correlation between parental rearing, personality traits, and obsessive–compulsive disorder (OCD) in different quantiles. In particular, we created an intermediary effect model in which parental rearing affects OCD through personality traits. All predictors were measured at the time of the survey, comprising parental rearing (paternal rearing and maternal rearing), demographics (grade and gender), and personality traits (neuroticism, extroversion, and psychoticism). These results suggest that (a) paternal emotional warmth was negatively correlated with OCD at the 0.40–0.80 quantile, while maternal emotional warmth was positively correlated with the OCD at the 0.45–0.69 quantile. (b) The correlation between negative parental rearing and OCD ranged from the 0.67 to 0.95 quantile for paternal punishment, 0.14–0.82 quantile for paternal overprotection, 0.05–0.36 and >0.50 quantile for maternal over-intervention and overprotection, and 0.08–0.88 quantile for maternal rejection. (c) Extroversion, neuroticism, and psychoticism were not only associated with OCD in a particular quantile but also mediated between parental rearing (namely parental emotional warmth, paternal punishment, paternal overprotection, maternal rejection, maternal over-intervention, and overprotection) and OCD. These findings provide targets for early interventions of OCD to improve the form of family education and personality traits and warrant validation.
The prediction of prognosis is an important part of management in hepatitis B virus (HBV)-related decompensated cirrhosis patients with high long-term mortality. Lactate is a known predictor of outcome in critically ill patients. The aim of this study was to assess the prognostic value of lactate in HBV-related decompensated cirrhosis patients. We performed a single-centre, observational, retrospective study of 405 HBV-related decompensated cirrhosis patients. Individuals were evaluated within 24 h after admission and the primary outcome was evaluated at 6-months. Multivariable analyses were used to determine whether lactate was independently associated with the prognosis of HBV-related decompensated cirrhosis patients. The area under the ROC (AUROC) was calculated to assess the predictive accuracy compared with existing scores. Serum lactate level was significantly higher in non-surviving patients than in surviving patients. Multivariable analyses demonstrated that lactate was an independent risk factor of 6-months mortality (odds ratio: 2.076, P < 0.001). Receiver operating characteristic (ROC) curves were drawn to evaluate the discriminative ability of lactate for 6-months mortality (AUROC: 0.716, P < 0.001). Based on our patient cohort, the new scores (Model For End-Stage Liver Disease (MELD) + lactate score, Child–Pugh + lactate score) had good accuracy for predicting 6-months mortality (AUROC = 0.769, P < 0.001; AUROC = 0.766, P < 0.001). Additionally, the performance of the new scores was superior to those of existing scores (all P < 0.001). Serum lactate at admission may be useful for predicting 6-months mortality in HBV-related decompensated cirrhosis patients, and the predictive value of the MELD score and Child–Pugh score was improved by adjusting lactate. Serum lactate should be part of the rapid diagnosis and initiation of therapy to improve clinical outcome.
Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch (PCSS) with a burst-mode fibre laser. The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS. To obtain a high-performance microwave signal, a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect. Resulting from the technique, homogenous peak power distribution in each burst is ensured. The maximum energy of the laser burst pulse reaches 200 μJ with a burst duration of 100 ns at the average power of 10 W, corresponding to a peak power of 4 kW. When the PCSS is illuminated by the burst-mode fibre laser, narrowband microwave generation with tuneable frequency (0.80–1.12 GHz) is obtained with a power up to 300 W. To the best of the authors’ knowledge, it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser. The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.
The coronavirus disease 2019 (COVID-19) outbreak has become a pandemic. Obstetricians and midwives, among other medical staff, are tackling COVID-19 and are under immense psychological stress.
We aimed to survey the mental health of non-infectious disease specialist staff, specifically obstetricians and midwives, working in officially designated hospitals treating patients with COVID-19.
A nationwide online survey was conducted from 7 March to 17 March 2020 investigating the mental health of obstetricians and midwives (who were not themselves infected with COVID-19) working in hospitals treating patients with COVID-19. We used the 9-item Patient Health Questionnaire (PHQ-9), the 7-item Generalized Anxiety Disorder (GAD-7) scale and the 7-item Insomnia Severity Index (ISI) to assess their symptoms of depression, anxiety and insomnia.
A total of 885 (41.6%), 609 (28.6%) and 729 (34.3%) obstetricians and midwives reported depression (PHQ-9 ≥ 5), anxiety (GAD-7 ≥ 5) and insomnia (ISI ≥ 8), respectively, during the COVID-19 pandemic. Regardless of whether or not they had direct contact with patients with COVID-19, obstetricians and midwives were more likely to report mild and moderate depression and anxiety during the COVID-19 pandemic when compared with before the pandemic. Those who had direct contact with patients with COVID-19 were more likely to report depression and insomnia than those who did not. Those who had sufficient protective equipment or training were less likely to report depression, anxiety and insomnia than those who did not.
Our data suggest that non-infectious disease specialist staff have experienced varying, but increased levels of depression, anxiety and insomnia during this COVID-19 pandemic, which could be reduced by sufficient levels of protective equipment and occupational COVID-19 workplace training.
A compact ultrawideband (UWB) antenna with reconfigurable triple band notch characteristics is proposed in this paper. The antenna consists of a coplanar waveguide-fed top-cut circular-shaped radiator with two etched C-shaped slots, a pair of split-ring resonators (SRRs) on the backside and four p-type intrinsic n-type (PIN) diodes integrated in the slots and SRRs. By controlling the current distribution in the slots and SRRs, the antenna can realize eight band notch states with independent switch ability, which allows UWB to coexist with 5G (3.3–4.4 GHz)/WiMAX (3.3–3.6 GHz), WLAN (5.15–5.825 GHz), and X-band (7.9–8.4 GHz) bands without interference. By utilizing a nested structure of C-shaped slots and SRRs on the backside, a compact size of 18 × 19.5 mm2 is achieved along with multimode triple band notch reconfigurability. The antenna covers a bandwidth of 3.1–10.6 GHz. A prototype is fabricated and tested. The simulated and experimental results are in good agreement.
Colour is widely utilised as a visual coding system in visual search, but its application under vibration conditions (e.g., in various vehicles) has not been fully explored. This study was designed to examine the effect of colour combinations on performance of visual search tasks conducted in vibration conditions. Forty-eight university students participated in an experiment where they were required to identify target type and location under 24 colour combinations (half in negative polarity and half in positive polarity) and three vibration conditions (static, low, and high). The findings showed that vibration did not significantly affect performance, perceptions, or physiological aspects. Colour combination significantly affected response time, and the participants preferred colour combinations that had the potential to produce better performance. Colour combinations with negative polarity (e.g., yellow on black and white on black) are recommended for presenting search interfaces. These findings are of importance in human–computer interface designs for information display under vibration conditions.
The impact of diet on the metabolic syndrome (MetS) and CVD has been investigated widely, but few studies have investigated the association between dietary patterns (DP) and the predicted CVD, derived from reduced rank regression (RRR). The objectives of this study were to derive DP using RRR and principal component analysis (PCA) and investigate their associations with the MetS and estimated 10-year atherosclerotic CVD (ASCVD). We used the baseline dataset from the Xinjiang multi-ethnic cohort study in China, collected from June 2018 to May 2019. A total of 14 982 subjects aged 35–74 years from Urumqi, Huo Cheng and Mo Yu were included in the analysis. The 10-year ASCVD risk was estimated using the Chinese ASCVD risk equations. The associations of DP with the MetS and 10-year ASCVD were determined using multivariable logistic regression models. In Urumqi and Mo Yu, the increased RRR DP score was associated with a higher OR of having the MetS and with a higher OR of elevated 10-year ASCVD risk. However, only the first DP determined by PCA in Urumqi was inversely associated with the MetS and elevated 10-year ASCVD risk. The prevalence of the MetS and elevated ASCVD risk in urban population is higher than that in rural areas. Our results may help nutritionists develop more targeted dietary strategies to prevent the MetS and ASCVD in different regions in China.
To evaluate the effects of dietary Ca intake and Ca supplementation during pregnancy on low birth weight (LBW) and small for gestational age (SGA) infants.
A birth cohort study was conducted in 2010–2012 at the Gansu Provincial Maternity and Child Care Hospital in Lanzhou, China.
A birth cohort study.
Totally, 9595 pregnant women who came to the hospital for delivery at 20 weeks of gestation or more, and who were 18 years of age or older.
Compared with non-users, Ca supplement users had a reduced risk of LBW infants (OR = 0·77, 95 % CI: 0·63, 0·95) and a reduced risk of nulliparous women giving birth to LBW infants (OR = 0·75, 95 % CI: 0·58, 0·98) (P < 0·05). More specifically, both the use of Ca supplement before conception and during pregnancy (OR = 0·44, 95 % CI: 0·19, 0·99) and during pregnancy only (OR = 0·80, 95 % CI: 0·65, 0·99) had the main effect of reducing risk of nulliparous women giving birth to LBW infants (P < 0·05). There was no association between Ca supplementation and SGA (OR = 0·87, 95 % CI: 0·75, 1·01) (P > 0·05). However, higher dietary Ca intake during pregnancy decreases the risk of both LBW (quartile 2: OR = 0·72, 95 % CI: 0·55, 0·94; quartile 3: OR = 0·68, 95 % CI: 0·50, 0·62) and SGA infants (quartile 2: OR = 0·77, 95 % CI: 0·63, 0·95; quartile 3: OR = 0·71, 95 % CI: 0·57, 0·88, quartile 4: OR = 0·71, 95 % CI: 0·57, 0·88) (P < 0·05).
Ca supplementation and adequate dietary intake of Ca during pregnancy are associated with a decreased risk of LBW infants born to nulliparous women.
The cellular accumulation of drug delivery systems (DDSs) is a critical parameter to determine the final outcome of cancer chemotherapy. Herein, we designed a red blood cells membrane-based vehicle (RV) and employed it to load both doxorubicin (Dox) and IR 780 (RV/I-D). The photothermal-assisted chemotherapy efficacy of RV/I-D on the treatment of cancer was tested on a prostate cancer model. Excitingly, the results showed that RV/I-D was stable and safe nanoparticles with size at about 100 nm. Moreover, upon the increase of system temperature using photothermal effects of IR780, the drug release of the DDS was accelerated. Above all, the DDS also increased the accumulation of drugs into the Dox-resistant prostate cancer cells (PC-3/Dox) both in vitro and in vivo and showed enhanced anticancer performance.
Three-dimensional porous materials with the hydrophobic/oleophilic surface have attracted significant interest in the fields of oil/water separation. In this paper, superhydrophobic magnetic polyurethane sponge was fabricated by the self-polymerization of dopamine to bind the Fe3O4 nanoparticles tightly on the sponge and then soaking in cheap stearic acid aqueous solution. The obtained sponge has the superhydrophobic property and good magnetic property. The surface structure, composition, and properties of the modified sponges were characterized by scanning electron microscopy, energy dispersive spectrometer, Fourier-transform infrared spectrum, and water contact angle (WCA) measurements. The as-prepared superhydrophobic magnetic sponge was able to collect a wide range of oils and organic solvents from oil–water mixture with an absorption capacity up to 16–60 times of its own weight. Under an external magnetic field, it can be guided to a designated area. In addition, combined with the vacuum system, continuous oil separation can be carried out, which is of great significance for removing a good deal of dirty oil on the water surface. Furthermore, the WCA of sponge remains above 141°, and the oil absorption is basically unchanged through repeated cyclic experiments.
A–Ar–A-type small molecule (SM) of Py-2DTOBT and Py-2DTOBTPh with an Ar(A–D)2 framework were synthesized, in which 2,7-pyrene (Py) and alkoxyl-substituted benzothiadiazole (OBT) were, respectively, used as the central aryl (Ar) and arm acceptor (A), while 3-phenanthrene (Ph) was used as a terminal donor (D) in Py-2DTOBTPh. By comparison with the parent SM of Py-2DTBT, where 2,7-pyrene (Py) and benzothiadiazole (BT) were used as the central aryl (Ar) and arm acceptor (A), the effects of non-covalent interactions and the terminal group on optical, electrochemical, and photovoltaic properties were investigated. The gradually improved photovoltaic performances were observed among Py-2DTBT, Py-2DTOBT, and Py-2DTOBTPh based organic solar cells. A power conversion efficiency (PCE) of 2.83% was obtained in the Py-2DTOBTPh/PC71BM-based device, which is a 53% improvement related to that of Py-2DTOBT and three times enhanced related to that of Py-2DTBT(Py-2DTOBT:PCE of 1.86%, Py-2DTBT:PCE of 0.74%).