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Attention-deficit/hyperactivity disorder (ADHD) patients exhibit characteristics of impaired working memory (WM) and diminished sensory processing function. This study aimed to identify the neurophysiologic basis underlying the association between visual WM and auditory processing function in children with ADHD.
Methods
The participants included 86 children with ADHD (aged 6–15 years, mean age 9.66 years, 70 boys, and 16 girls) and 90 typically developing (TD) children (aged 7–16 years, mean age 10.30 years, 66 boys, and 24 girls). Electroencephalograms were recorded from all participants while they performed an auditory discrimination task (oddball task). The visual WM capacity and ADHD symptom severity were measured for all participants.
Results
Compared with TD children, children with ADHD presented a poorer visual WM capacity and a smaller mismatch negativity (MMN) amplitude. Notably, the smaller MMN amplitude in children with ADHD predicted a less impaired WM capacity and milder inattention symptom severity. In contrast, the larger MMN amplitude in TD children predicted a better visual WM capacity.
Conclusions
Our results suggest an intimate relationship and potential shared mechanism between visual WM and auditory processing function. We liken this shared mechanism to a total cognitive resource limit that varies between groups of children, which could drive correlated individual differences in auditory processing function and visual WM. Our findings provide a neurophysiological correlate for reports of WM deficits in ADHD patients and indicate potential effective markers for clinical intervention.
This study aimed to investigate the effects of physical multimorbidity on the trajectory of cognitive decline over 17 years and whether vary across wealth status. The study was conducted in 9035 respondents aged 50+ at baseline from nine waves (2002–2019) of the English Longitudinal Study of Aging. A latent class analysis was used to identify patterns of physical multimorbidity, and mixed multilevel models were performed to determine the association between physical multimorbidity and trajectories of cognitive decline. Joint analyses were conducted to further verify the influence of wealth status. Four patterns of physical multimorbidity were identified. Mixed multilevel models with quadratic terms of time and status/patterns indicated significant non-linear trajectories of multimorbidity on cognitive function. The magnitude of the association between complex multisystem patterns and cognitive decline increased the most as follow-up progressed. Individuals with high wealth and hypertension/diabetes patterns have significantly lower composite global cognitive z scores over time as compared with respiratory/osteoporosis patterns. Physical multimorbidity at baseline is associated with the trajectory of cognitive decline, and the magnitude of the association increased over time. The trend of cognitive decline differed in specific combinations of wealth status and physical multimorbidity.
This paper proposes a cooperative midcourse guidance law with target changing and topology switching for multiple interceptors intercepting targets in the case of target loss and communication topology switching. Firstly, a three-dimensional guidance model is established and a cooperative trajectory shaping guidance law is given. Secondly, the average position consistency protocol of virtual interception points is designed for communication topology switching, and the convergence of the average position of virtual interception points under communication topology switching is proved by Lyapunov stability theory. Then, in the case of the target changing, the target handover law and the handover phase guidance law are designed to ensure the acceleration smoothing, at last, the whole cooperative midcourse guidance law is given based on the combination of the above guidance laws. Finally, numerical simulation results show the effectiveness and the superiority of the proposed cooperative midcourse guidance law.
This study aimed to assess the relationship between COVID-19 infection-related conditions and depressive symptoms among medical staff after easing the zero-COVID policy in China, and to further examine the mediating role of professional burnout.
Methods
A total of 1716 medical staff from all levels of health care institutions in 16 administrative districts of Beijing, China, were recruited to participate at the end of 2022 in this cross-sectional study. Several multiple linear regressions and mediating effects tests were performed to analyze the data.
Results
At the beginning of the end of the zero-COVID policy in China, 91.84% of respondents reported infection with COVID-19. After adjusting for potential confounding variables, the severity of infection symptoms was significantly positively associated with high levels of depressive symptoms (β = 0.06, P < 0.001), and this association was partially mediated by professional burnout. Specifically, emotional exhaustion (95% CI, 0.131, 0.251) and depersonalization (95% CI, 0.009, 0.043) significantly mediated the association between the severity of infection symptoms and depressive symptoms.
Conclusions
The mental health of medical staff with more severe symptoms of COVID-19 infection should be closely monitored. Also, interventions aimed at reducing emotional exhaustion and depersonalization may effectively reduce their risk of developing depressive symptoms.
As a member of the Scathophagidae family, Scathophaga stercoraria (S. stercoraria) is widely distributed globally and is closely associated with animal feces. It is also a species of great interest to many scientific studies. However, its phylogenetic relationships are poorly understood. In this study, S. stercoraria was found in plateau pikas for the first time. The potential cause of its presence in the plateau pikas was discussed and it was speculated that the presence of S. stercoraria was related to the yak feces. In addition, 2 nuclear genes (18SrDNA and 28SrDNA), 1 mitochondrial gene (COI), and the complete mitochondrial genome of S. stercoraria were sequenced. Phylogenetic trees constructed based on 13 Protein coding genes (13PCGs), 18S and 28S rDNA showed that S. stercoraria is closely related to the Calliphoridae family; phylogenetic results based on COI suggest that within the family Scathophagidae, S. stercoraria is more closely related to the genus Leptopa, Micropselapha, Parallelomma and Americina. Divergence times estimated using the COI gene suggest that the divergence formation of the genus Scathophaga is closely related to changes in biogeographic scenarios and potentially driven by a combination of uplift of the Qinghai-Tibetan Plateau (QTP) and dramatic climate changes. These results provide valuable information for further studies on the phylogeny and differentiation of the Scathophaga genus in the future.
We report the unified constitutive law of vibroconvective turbulence in microgravity, i.e. $Nu \sim a^{-1} Re_{os}^\beta$ where the Nusselt number $Nu$ measures the global heat transport, $a$ is the dimensionless vibration amplitude, $Re_{os}$ is the oscillational Reynolds number and $\beta$ is the universal exponent. We find that the dynamics of boundary layers plays an essential role in vibroconvective heat transport and the $Nu$-scaling exponent $\beta$ is determined by the competition between the thermal boundary layer (TBL) and vibration-induced oscillating boundary layer (OBL). Then a physical model is proposed to explain the change of scaling exponent from $\beta =2$ in the TBL-dominant regime to $\beta = 4/3$ in the OBL-dominant regime. Our finding elucidates the emergence of universal constitutive laws in vibroconvective turbulence, and opens up a new avenue for generating a controllable effective heat transport under microgravity or even microfluidic environment in which the gravity effect is nearly absent.
The Righi–Leduc heat flux generated by the self-generated magnetic field in the ablative Rayleigh–Taylor instability driven by a laser irradiating thin targets is studied through two-dimensional extended-magnetohydrodynamic simulations. The perturbation structure gets into a low magnetization state though the peak strength of the self-generated magnetic field could reach hundreds of teslas. The Righi–Leduc effect plays an essential impact both in the linear and nonlinear stages, and it deflects the total heat flux towards the spike base. Compared to the case without the self-generated magnetic field included, less heat flux is concentrated at the spike tip, finally mitigating the ablative stabilization and leading to an increase in the velocity of the spike tip. It is shown that the linear growth rate is increased by about 10% and the amplitude during the nonlinear stage is increased by even more than 10% due to the feedback of the magnetic field, respectively. Our results reveal the importance of Righi–Leduc heat flux to the growth of the instability and promote deep understanding of the instability evolution together with the self-generated magnetic field, especially during the acceleration stage in inertial confinement fusion.
Iodine and thyroid hormones (TH) transport in the placenta are essential for fetal growth and development, but there is little research focus on the human placenta. The research aimed to investigate iodine and TH transport mechanisms in the human placenta. The placenta was collected from sixty healthy pregnant women. Urinary iodine concentration (UIC), serum iodine concentration (SIC), placenta iodine storage (PIS) and the concentration of serum and placenta TH were examined. Five pregnant women were selected as insufficient intake (II), adequate intake (AI) and above requirements intake (ARI) groups. Localisation/expression of placental sodium/iodide symporter (NIS) and Pendrin were also studied. Results showed that PIS positively correlated with the UIC (R = 0·58, P < 0·001) and SIC (R = 0·55, P < 0·001), and PIS was higher in the ARI group than that in the AI group (P = 0·017). NIS in the ARI group was higher than that in the AI group on the maternal side of the placenta (P < 0·05). NIS in the II group was higher than that in the AI group on the fetal side (P < 0·05). In the II group, NIS on the fetal side was higher than on the maternal side (P < 0·05). Pendrin was higher in the II group than in the AI group on the maternal side (P < 0·05). Free triiodothyronine (r = 0·44, P = 0·0067) and thyroid-stimulating hormone (r = 0·75, P < 0·001) between maternal and fetal side is positively correlated. This study suggests that maternal iodine intake changes the expression of NIS and Pendrin, thereby affecting PIS. Serum TH levels were not correlated with placental TH levels.
Carbon isotope analysis of pedogenic carbonate (δ13CCarb) and soil organic matter (δ13CTOC) is widely applied in reconstructions of terrestrial paleovegetation. The δ13C of different archives is considered well matched and equally reflects the proportion of C3/C4 plant biomass covering the soil profile. However, modern soil and paleosol sequences provide substantial evidence that δ13CCarb and δ13CTOC do not always match, raising doubts about the accuracy of quantitative C4 plant reconstructions. Here we report paired δ13C records of pedogenic carbonates and organic matter occluded within carbonate nodules from the Shaozhai section in the central Chinese Loess Plateau (CLP). The δ13CCarb record exhibits a positive anomaly and exceeds the theoretical fractionation range with the coexisting δ13CTOC record during the expansion of C4 plants. The possibility of contamination by detrital carbonates and atmospheric CO2 affecting δ13CCarb was ruled out based on the morphological features, mineral fractions, and geochemical composition of carbonate nodules. Our study suggests that the enhanced respiration of C4 plants during pedogenic carbonate precipitation may have caused positive shifts in δ13CCarb records, supporting the hypothesis that the discrepancy in carbon sources explains the δ13CCarb positive anomaly. Thus, the δ13CCarb could reflect the maximum relative abundance of C4 plants during their metabolic peaks.
The demand for flexible grasping of various objects by robotic hands in the industry is rapidly growing. To address this, we propose a novel variable stiffness gripper (VSG). The VSG design is based on a parallel-guided beam structure inserted by a slider from one end, allowing stiffness variation by changing the length of the parallel beams participating in the system. This design enables continuous adjustment between high compliance and high stiffness of the gripper fingers, providing robustness through its mechanical structure. The linear analytical model of the deflection and stiffness of the parallel beam is derived, which is suitable for small and medium deflections. The contribution of each parameter of the parallel beam to the stiffness is analyzed and discussed. Also, a prototype of the VSG is developed, achieving a stiffness ratio of 70.9, which is highly competitive. Moreover, a vision-based force sensing method utilizing ArUco markers is proposed as a replacement for traditional force sensors. By this method, the VSG is capable of closed-loop control during the grasping process, ensuring efficiency and safety under a well-defined grasping strategy framework. Experimental tests are conducted to emphasize the importance and safety of stiffness variation. In addition, it shows the high performance of the VSG in adaptive grasping for asymmetric scenarios and its ability to flexible grasping for objects with various hardness and fragility. These findings provide new insights for future developments in the field of variable stiffness grippers.
Fast neutron absorption spectroscopy is widely used in the study of nuclear structure and element analysis. However, due to the traditional neutron source pulse duration being of the order of nanoseconds, it is difficult to obtain a high-resolution absorption spectrum. Thus, we present a method of ultrahigh energy-resolution absorption spectroscopy via a high repetition rate, picosecond duration pulsed neutron source driven by a terawatt laser. The technology of single neutron count is used, which results in easily distinguishing the width of approximately 20 keV at 2 MeV and an asymmetric shape of the neutron absorption peak. The absorption spectroscopy based on a laser neutron source has one order of magnitude higher energy-resolution power than the state-of-the-art traditional neutron sources, which could be of benefit for precisely measuring nuclear structure data.
This study investigates the effect of vibration on the flow structure transitions in thermal vibrational convection (TVC) systems, which occur when a fluid layer with a temperature gradient is excited by vibration. Direct numerical simulation (DNS) of TVC in a two-dimensional enclosed square box is performed over a range of dimensionless vibration amplitudes $0.001 \le a \le 0.3$ and angular frequencies $10^{2} \le \omega \le 10^{7}$, with a fixed Prandtl number of 4.38. The flow visualisation shows the transition behaviour of flow structure upon the varying frequency, characterising three distinct regimes, which are the periodic-circulation regime, columnar regime and columnar-broken regime. Different statistical properties are distinguished from the temperature and velocity fluctuations at the boundary layer and mid-height. Upon transition into the columnar regime, columnar thermal coherent structures are formed, in contrast to the periodic oscillating circulation. These columns are contributed by the merging of thermal plumes near the boundary layer, and the resultant thermal updrafts remain at almost fixed lateral position, leading to a decrease in fluctuations. We further find that the critical point of this transition can be described nicely by the vibrational Rayleigh number ${{Ra}}_{vib}$. As the frequency continues to increase, entering the so-called columnar-broken regime, the columnar structures are broken, and eventually the flow state becomes a large-scale circulation (LSC), characterised by a sudden increase in fluctuations. Finally, a phase diagram is constructed to summarise the flow structure transition over a wide range of vibration amplitude and frequency parameters.
Arising of disasters by climate change had affected crop growth and yield, and then threaten local to global food security, particularly heat stress. Therefore, hazard assessment is essential to develop effective disaster risk management and adaptation interventions to ensure food security. In this study, the accumulated heat stress days (DAY), heat stress intensity (HSI) and heat degree-days (HDD) during the post-silking period of summer maize in The Huang-Huai-Hai Plain were investigated. Based on the optimal probability distribution function of HDD and information diffusion theory, we compute heat stress classification index and the possibility of heat stress, respectively. During 1981–2019, DAY, HSI and HDD were 11.8 d, 31.9°C and 23.6°Cd and increased by 0.67 d/decade, 0.10°C/decade and 3.14°Cd/decade, respectively. The threshold and hazard probability of mild, moderate and severe heat stress were 9.4, 19.4 and 34.2°Cd and 16.6, 9.3 and 4.5%, respectively. The heat stress hazard index (M) was 0.48, ranged from 0 to 0.77 during 1981 to 2019. M will increase in the future at all regions, particularly after 2060. Under SSP5-8.5 climate scenario, M ranged from 0.95 to 1.20 in 2080s, about two times than historical period. This could be used in optimizing agricultural management in summer maize production in order to combat heat stress under projected climate change.
In this paper, to address the cooperative localisation of a heterogeneous UAV swarm in the GNSS-denied environment, an adaptive simulated annealing-particle swarm optimisation (SA-PSO) cooperative localisation algorithm is proposed. Firstly, the forming principle of the communication and measurement framework is investigated in light of a heterogeneous UAV swarm composition. Secondly, a reasonably cooperative localisation function is established based on the proposed forming principle, which can minimise the relative localisation error with limited available information. Then, an adaptive weight principle is incorporated into the particle swarm optimisation (PSO) for better performance. Furthermore, in order to overcome the drawbacks of PSO algorithm easily falling into the local extreme point, an adaptive SA-PSO algorithm is improved to promote the convergence speed of cooperative localisation. Finally, comparative simulations are performed among the adaptive SA-PSO, adaptive PSO, and PSO algorithms to demonstrate the feasibility and superiority of the proposed adaptive SA-PSO algorithm. Simulation results show that the proposed algorithm has better performance in convergence speed, and the cooperative localisation precision can be guaranteed.
This study examines family context and sexual debut among young people in China. Using data from the 2018 Panel Study of Chinese University Students (PSCUS), it explores how the family is correlated with sexual debut among young people in China aged 18–24 years. The Kaplan–Meier method was adopted to detect a survival function for different family factors and related demographic variables. Cox proportional hazard regression analysis was adopted to calculate hazard ratios for the timing of sexual debut. The average age of sexual debut among the college students was 18.39 years. The Kaplan–Meier analysis showed that sexual intercourse initiation was earlier for female students who had no siblings, and those who had a mother with senior high school (including technical school) education or higher family income, but this correlation was insignificant among male students. The multivariate hazard regression analysis revealed that living in a family with a higher level of fathers’ education, having a lower level of family income and having siblings had positive correlations with later sexual debut among the college students. Moreover, family factors showed gender differences in their associations with the timing of sexual debut, typically parent’s education level, family income and left-behind experience. This study provides a comprehensive perspective on the role of family influences in timing of sexual debut among youth in China.
We conducted the first detailed mineral magnetic investigation of more than nine loess–paleosol couplets of the composite Titel-Stari Slankamen loess section in Serbia, which provides one of the longest and most complete terrestrial record of paleoclimatic changes in Europe since ~1.0 Ma. The results show that the ferrimagnetic mineral assemblage of the loess units is dominated by partially oxidized multidomain (MD) and pseudo-single domain (PSD) magnetite; however, with an increasing degree of pedogenesis, the eolian contribution is gradually masked by pedogenic superparamagnetic(SP) and single-domain (SD) ferrimagnets (mainly maghemite). The overall consistency of ferrimagnetic grain-size parameters indicates an absence of dissolution of the fine-grained ferrimagnetic fraction despite changes in climate regime over the past 1.0 Ma. The variations of normalized dJ/dT@120K and normalized χheating@530°C reflect a long-term stepwise increase in aridity during glacials with a major step at ~0.6–0.5 Ma, over the last 1.0 Ma. Overall, the results provide an improved basis for the future use of the magnetic properties of Serbian loess deposits for paleoclimatic reconstruction.
Wave radiation and diffraction problems of a body floating in an open water channel confined by two semi-infinite ice sheets are considered. The linearized velocity potential theory is used for fluid flow and a thin elastic plate model is adopted for the ice sheet. The Green function, which satisfies all the boundary conditions apart from that on the body surface, is first derived. This is obtained through applying Fourier transform in the longitudinal direction of the channel, and matched eigenfunction expansions in the transverse plane. With the help of the derived Green function, the boundary integral equation of the potential is derived and it is shown that the integrations over all other boundaries, including the bottom of the fluid, free surface, ice sheet, ice edge as well as far field will be zero, and only the body surface has to be retained. This allows the problem to be solved through discretization of the body surface only. Detailed results for hydrodynamic forces are provided, which are generally highly oscillatory owing to complex wave–body–channel interaction and body–body interaction. In depth investigations are made for the waves confined in a channel, which does not decay at infinity. Through this, a detailed analysis is presented on how the wave generated by a body will affect the other bodies even when they are far apart.
The aeolian loess-paleosol sequences in the Chinese Loess Plateau (CLP) are an excellent archive of variations in atmospheric circulation in the geological past. However, there is no consensus regarding the roles of the East Asian winter monsoon and westerly winds in transporting the dust responsible for loess deposition during glacial and interstadial periods. We conducted detailed measurements of the anisotropy of magnetic susceptibility (AMS) on two parallel loess profiles covering the most recent 130 ka in the western CLP to determine paleowind directions. Results show that the magnetic lineations of the loess and paleosol units in both sections are significantly clustered along the northwest to southeast direction. These observations demonstrate that the prevailing wind system responsible for dust transport in the western CLP was the northwesterly winter monsoon, rather than the westerly winds. The AMS-derived dust-bearing wind direction was relatively stable during the last glacial and interglacial cycle in the western CLP, consistent with sedimentary and AMS evidence from the eastern CLP. Accordingly, it is reasonable to conclude that large areas of deserts and Gobi deserts areas located in the upwind direction were the dominant sources for the aeolian deposits of the Loess Plateau.
Echinococcus shiquicus is currently limited to the Qinghai–Tibet plateau, a large mountainous region in China. Although the zoonotic potential remains unknown, progress is being made on the distribution and intermediate host range. In this study, we report E. shiquicus within Gansu and Qinghai provinces in regions located not only around the central areas but also the southeast edge of the plateau and describe their genetic relationship with previous isolates from the plateau. From 1879 plateau pikas examined, 2.39% (95% CI 1.79–3.18) were infected with E. shiquicus. The highest prevalence of 10.26% (4.06–23.58) was recorded in Makehe town, Qinghai province. Overall the prevalence was marginally higher in Qinghai (2.5%, CI 1.82–3.43) than in Gansu (2%, CI 1.02–3.89). The cox1 and nad1 genes demonstrated high and low haplotype and nucleotide diversities, respectively. The median-joining network constructed by the cox1–nad1 gene sequences demonstrated a star-like configuration with a median vector (unsampled haplotype) occupying the centre of the network. No peculiar distinction or common haplotype was observed in isolates originating from the different provinces. The presence of E. shiquicus in regions of the southeast and northeast edges of the Qinghai–Tibet plateau and high genetic variation warrants more investigation into the haplotype distribution and genetic polymorphism by exploring more informative DNA regions of the mitochondrial genome to provide epidemiologically useful insight into the population structure of E. shiquicus across the plateau and its axis.