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Abstract The IPv6 extension header mechanism, a new feature of the IPv6 protocol, enhances flexibility and scalability but introduces numerous security threats like firewall evasion and covert channels. Existing threat detection methods face limitations in detection types, universality, and speed. Hence, an adaptive detection model for IPv6 extension header threats (ADM-DDA6) is proposed. Firstly, standard rule sets are designed for common IPv6 extension headers, successfully detecting 70 types of threats from THC-IPv6 and ExtHdr tools using only 20 rules. Secondly, by parsing IPv6 extension headers, matching rules, establishing transition relationships, and deciding packet threat status based on final states (Normal or Abnormal), complex threats like header disorder and header repetition can be detected. Finally, an adaptive rule matching method is introduced, which dynamically selects rule sets based on IPv6 extension header types, effectively reducing rule matching time. Experimental results show that under different threat magnitudes, ADM-DDA6 is 32% faster than Suricata v6.0.12 and 21.2% faster than Snort v3.1.61.0 in detection speed. Additionally, as the number of threats increases, on commodity hardware, ADM-DDA6 incurs only a 0.7% increase in CPU overhead with no significant memory consumption increase, maintains maximum throughput, and exhibits minor performance changes under low and moderate network load conditions.

Grassland, as highly vulnerable ecosystem, requires a comprehensive understanding of its dynamics and response patterns to climate factors in response to climate change challenges. While previous research has primarily centered on the influence of interannual climate variability on grassland Net Primary Productivity (NPP), knowledge of the impacts of seasonal or monthly climate variations on annual net primary productivity (ANPP) remains limited. This study investigated the climatic drivers of grassland NPP dynamics in Xinjiang's Altay region from 2000 to 2022 using the Carnegie-Ames-Stanford approach (CASA) model and the random forest regression model. The study examined the significance and patterns of precipitation, solar radiation, temperature, soil moisture, and snowmelt water on NPP at three temporal scales. The results revealed the following key findings: (1) Grassland NPP declined significantly from 2000 to 2009 but showed a gradual increase from 2009 to 2022. Spatially, higher values were observed in the northern region and lower values were observed in the southern region. (2) Precipitation was the primary influential climate factor affecting grassland NPP, followed by solar radiation, temperature, soil moisture, and snowmelt water. In determining the significance of climate factor timing on ANPP, June played a critical role particularly for precipitation, temperature, and soil moisture, while August was essential for solar radiation. Moreover, the importance of snowmelt water had a bimodal distribution, with peaks in April and October. (3) Grassland NPP exhibited diverse nonlinear response dynamics and spatial heterogeneity to various climate factors at different temporal scales. These findings highlight the importance of considering both the magnitude and the local conditions, as well as the timing of climate variations when studying grassland dynamic responses to climate change and predicting future impacts. These insights enhance the comprehension of the intricate dynamics of grassland ecosystems and enhance predictions of their responses to future climate change.

Deep-towed multichannel seismic exploration technology has better applicability and more development potential when utilized to invert the geoacoustic properties of deep-sea sediment. The accurate geometric inversion results of the receiving array are crucial for fine submarine sediment imaging and physical property parameter inversion based on deep-towed multichannel seismic data. Thus, this study presents an array geometry inversion method suitable for complex seafloors to address the challenge of precise source-receiver positioning. The objective function of the deep-towed seismic array geometry inversion is built using the shortest path algorithm according to the traveltimes of direct waves and seafloor reflections, and the particle swarm optimization algorithm is used to achieve high-precision inversion of the source-receiver position. The results showed that the proposed method is shown to have incomparable applicability and effectiveness in obtaining exact source-receiver positions for deep-towed multichannel seismic systems. Regardless of the complexity of the seabed morphology, seismic image processing techniques using the source-receiver position data obtained by the suggested method produce fine seismic imaging profiles that clearly and accurately reflect the structural characteristics of sediments. These findings provide insights for the accuracy and reliability of the proposed geometric shape inversion method for deep-towed seismic arrays in practical applications to meet the requirements of near-bottom acoustic detection for fine imaging of deep-sea seabed strata and precise inversion of geoacoustic parameters.

When the directional rotary steering system works in the state of maintaining the tool face angle, the use of PID control mode will lead to a large swing angle of the tool face angle of the directional rotary steering system. In order to reduce the swing amplitude of the tool face angle, based on the PID position control and the angle position error sliding mode control strategy, the exponential synovial control function is established. The simulation results show that the fast and accurate tool face angle tracking is achieved through the closed-loop control of the angle position. The paper provides an implementation method for the research of directional rotary steering system.

Temperature and precipitation are crucial indicators for investigating climate changes, necessitating precise measurements for rigorous scientific inquiry. While the Fifth Generation of European Centre for Medium-Range Weather Forecasts Atmospheric Reanalysis (ERA5), ERA5 of the Land Surface (ERA5-Land), and China Meteorological Forcing Dataset (CMFD) temperature and precipitation products are widely used worldwide, their suitability for the Altay region of arid and semi-arid areas has received limited attention. Here, we used the Altay region as the study area, utilizing meteorological station data and implementing the residual revision method for temperature and the coefficient revision method for precipitation to rectify inaccuracies in monthly temperature and precipitation records from ERA5-Land, ERA5, and CMFD. We evaluate the accuracy of these datasets before and after correction using bias, Taylor diagrams, and root-mean-square error (RMSE) metrics. Additionally, we employ Tropical Rainfall Measuring Mission satellite precipitation data (TRMM) as a benchmark to assess the performance of ERA5-Land, ERA5, and CMFD monthly precipitation before and after correction. The results revealed significant differences in the temperature and precipitation capture capabilities of ERA5-Land, ERA5, and CMFD in the Altay region. Overall, these data exhibit substantial errors and are not directly suitable for scientific research. However, we applied residual and coefficient revision methods. After this revision, ERA5-Land, ERA5, and CMFD showed significantly improved temperature and precipitation capture capabilities, especially for ERA5-Land. In terms of temperature, post-revision-CMFD (CMFDPR) demonstrated better temperature capture capabilities. All three datasets showed weaker performance in mountainous regions compared to plains. Notably, post-revision-ERA5 (ERA5PR) seemed unsuitable for capturing temperature in the Altay region. Concerning rain, CMFDPR, post-revision-ERA5-Land (ERA5-LandPR) and ERA5PR outperformed TRMM in capturing precipitation. CMFDPR and ERA5-LandPR both outperform ERA5PR. In summary, the revision datasets effectively compensated for the sparse distribution of meteorological stations in the Altay region, providing reliable data support for studying climate change in arid and semi-arid areas.

In Africa, vegetation is important for the protection of species habitats, maintaining local livelihoods, and the existence of wildlife. A comprehensive evaluation of vegetation dynamics using solar-induced fluorescence (SIF) is needed to acquire important information to understand the current situation of how ecosystems react to human activities and climate change, as well as for conservation planning. The research’s purpose was to detect vegetation dynamics in Africa from 2000 to 2017 using global, OCO-2-based SIF (GOSIF) and various datasets, as well as to analyze the factors influencing vegetation changes. The main findings revealed that: (1) The patterns for various vegetation in this study showed that forests experienced more vegetation expansions than croplands, grasslands, shrubland, and sparse vegetation, based on the Land Use Cover Change (LUCC) per vegetation type. (2) According to SIF, the decreasing area accounts for 29.4% of the total vegetation region while expanding area accounts for 70.6%. (3) The Hurst exponent summary exhibited that the majority of studied vegetation variations are consistent and accounted for 79.7%. (4) Based on the residual, we discovered that climatic patterns might be responsible for the greening trend of sparse vegetation and grassland. (5) The Boosted Regression Trees (BRT) showed that during the study period, Vapor pressure deficit (VPD) and the temperature had a greater impact on SIF vegetation dynamics than other factors. Our findings can aid in the development of appropriate vegetation management concepts or strategies to help in vegetation restoration in Africa.

The arid terrestrial ecosystem carbon cycle is one of the most important parts of the global carbon cycle, but it is vulnerable to external disturbances. As the most direct factor affecting the carbon cycle, how land cover change affects vegetation carbon sources/sinks in arid terrestrial ecosystems remains unclear. In this study, we chose the arid region of northwest China (ARNWC) as the study area and used net ecosystem productivity (NEP) as an indicator of vegetation carbon source/sink. Subsequently, we described the spatial distribution and temporal dynamics of vegetation carbon sources/sinks in the ARNWC from 2001–2018 by combining the Carnegie-Ames-Stanford Approach (CASA) and a soil microbial heterotrophic respiration (RH) model and assessed the effects of land cover change on them through modeling scenario design. We found that land cover change had an obvious positive impact on vegetation carbon sinks. Among them, the effect of land cover type conversion contributed to an increase in total NEP of approximately 1.77 Tg C (reaching 15.55% of the original value), and after simultaneously considering the effect of vegetation growth enhancement, it contributed to an increase in total NEP of approximately 14.75 Tg C (reaching 129.61% of the original value). For different land cover types, cropland consistently contributed the most to the increment of NEP, and the regeneration of young and middle-aged forests also led to a significant increase in forest carbon sinks. Thus, our findings provide a reference for assessing the effects of land cover change on vegetation carbon sinks, and they indicated that cropland expansion and anthropogenic management dominated the growth of vegetation carbon sequestration in the ARNWC, that afforestation also benefits the carbon sink capacity of terrestrial ecosystems, and that attention should be paid to restoring and protecting native vegetation in forestland and grassland regions in the future.

IntroductionDue to the actual limitation of training conditions, the freestyle skiing aerials winter training term is short. Training tasks such as adaptability training and developing new skills are needed in summer training. When facing different training environments, freestyle skiing aerial athletes’ executive control over their abilities could be affected, which can affect their performance. Therefore, we want to research the effect of training conditions on executive control in freestyle skiing aerials athletes and its neural mechanism.Materials and methodsThirty-two freestyle skiing aerials athletes were recruited. We evaluated their executive control and used fNIRS to measure oxygenated hemoglobin concentration changes in the prefrontal cortex during a rapid event-related design go/nogo task with different training condition-activated materials.ResultsAthletes’ behavior control in the summer condition has a lower accuracy than it is in the control condition. Athletes’ behavior control in the summer and winter training conditions had a longer reaction time than that in the control condition. The activation of the bilateral dlPFC and orbitofrontal cortex had a significant main effect across training conditions when freestyle skiing aerial athletes completed executive control tasks. The activation of athletes’ bilateral vlPFC and left dlPFC had an interaction between training conditions and behavioral control.ConclusionDifferent training conditions can lead to freestyle skiing aerial athletes executive control ability to drop, players in different training conditions show less activation on both sides of the vlPFC and orbitofrontal. The bilateral vlPFC and left dlPFC have an integrated effect on behavior inhibition across training conditions.

ObjectiveTo systematically evaluate the effects of physical exercise on the quality of life (QOL) of healthy older adults in China.MethodsRelevant articles published until December 2021 were retrieved from China National Knowledge Infrastructure, Wanfang, China Science and Technology Journal Database, PubMed, EBSCO, Web of Science, and the Library of Congress. Inclusion criteria were studies in which the subjects were healthy Chinese older adults (aged ≥ 60 years), the reported sample size was clear, and the study design was a randomized controlled trial or a research study. In addition, studies were included if they reported the use of at least one QOL questionnaire and investigated at least one form of physical exercise.ResultsIn total, 19 studies met the inclusion criteria, which included six studies that used comprehensive physical exercise type as an intervention and 13 studies that used regular physical exercise as an intervention. All 19 studies compared intervention and control groups, of which 12 (63%) were investigative studies and seven (37%) were experimental studies. Of the experimental studies, five used a positive control group and two used a negative control group. All 19 studies reported that physical exercise had varying degrees of positive effects on the QOL in older adults. Body–mind exercise was effective in improving the physical and mental health (MH) of older adults, whereas Xiyangcao only had a positive effect on physical health. Compared with no exercise or other exercise (exercise not used in the intervention group), the exercise group in the survey had a positive effect on the QOL of older adults. Regardless of the type of control group used, the exercise group in the experimental studies showed a positive effect of exercise on the QOL of older adults.ConclusionPhysical exercise has a positive impact on the QOL of healthy older adults. However, due to the wide and varied scope of the included studies, more randomized controlled trials are needed to examine the effects of different types, intensities, durations, and the frequency of exercise on QOL.Systematic Review Registration[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=220115], identifier: [CRD42020220115].

Beam pumping motor system (BPMS) is a typical periodic potential energy load which is affected by factors such as down-hole load, mechanical transmission and geological structure. During a running cycle, the power fluctuates in a large range and multiple operating conditions where potential energy, electrical energy and kinetic energy are converted to one another and thus leads to lower system efficiency. For this type of load, a four-quadrant inverter is an effective method to improve the efficiency of the motor system. However, in practice, the two-quadrant variable frequency control is widely used due to its lower cost. The drawback of this control is the difficulty in realizing efficient conversion and utilization of electrical energy under the power generation mode, since the generated electrical energy is converted into thermal energy by the installed resistance brake inside the inverter, which causes additional energy consumption. To resolve this problem, this paper systematically studies the influence of frequency regulation on the load torque of BPMS, an automatic tracking frequency regulation method is then proposed. With this method, the controllable conversion between the kinetic and potential energy forms can be realized, and the fluctuation power under dynamic load conditions can also be smoothed. Meanwhile, energy consumption in power generation mode is also reduced effectively. The correctness and practicability of the proposed method are verified by the simulations and experiments of a standard oil well. The results show that, comparing to the traditional two-quadrant inverter, the proposed method can reduce the active power fluctuation of the system by about 20% under the premise of still using a two-quadrant inverter, and the power saving ratio is increased by more than 10%.

In this study, we define the S0 value (buffer zone area centred on a meteorological station) and two inhomogeneity measurement parameters, the station domain area and station network density, for 89 weather stations in the Xinjiang region, and we construct the weight coefficient of the station network according to the station domain area. Applying the weight coefficient, we calculate the mean temperature, maximum temperature, and minimum temperature in January, April, July, October, and annually in the Xinjiang region from 1961 to 2021. The results show that the S0 value of 200,000 km2 is suitable for determining the weight coefficient of the station network in the Xinjiang region. The two measurement parameters can quantitatively reflect the inhomogeneity of the distribution of 89 weather stations in the Xinjiang region. The spatial distribution density of the station network is positively proportional to the station network density and inversely proportional to the station domain area and weight coefficient of the stations. The equal-weighted average is lower than the spatially homogenized revised average, which underestimates the mean temperature in the Xinjiang region, and the spatially homogenized revised average better reflects the real temperature in the Xinjiang region. The annual and monthly mean temperatures, maximum and minimum temperatures calculated by the spatially homogenized revised average, and the equal-weighted average have the same upwards trend, and the mean temperature warming trend calculated by the two methods have differences, but the differences are not significant. The annual, January, April, July, and October minimum temperature warming trends according to the spatial homogenization revised average are greater than the maximum temperature warming trend and the mean temperature warming trend, and the annual minimum temperature warming trend is 3.3 times the annual maximum warming trend and two times the annual mean temperature.

Asamitocins are maytansinoids produced by Actinosynnema pretiosum ssp. auranticum ATCC 31565 (A. pretiosum ATCC 31565), which have a structure similar to that of maytansine, therefore serving as a precursor of maytansine in the development of antibody-drug conjugates (ADCs). Currently, there are more than 20 known derivatives of ansamitocins, among which ansamitocin P-3 (AP-3) exhibits the highest antitumor activity. Despite its importance, the application of AP-3 is restricted by low yield, likely due to a substrate competition mechanism underlying the synthesis pathways of AP-3 and its byproducts. Given that N-demethylansamitocin P-3, the precursor of AP-3, is regulated by asm25 and asm10 to synthesize AGP-3 and AP-3, respectively, asm25 is predicted to be an inhibitory gene for AP-3 production. In this study, we inactivated asm25 in A. pretiosum ATCC 31565 by CRISPR-Cas9-guided gene editing. asm25 depletion resulted in a more than 2-fold increase in AP-3 yield. Surprisingly, the addition of isobutanol further improved AP-3 yield in the asm25 knockout strain by more than 6 times; in contrast, only a 1.53-fold increase was found in the WT strain under the parallel condition. Thus, we uncovered an unknown function of asm25 in AP-3 yield and identified asm25 as a promising target to enhance the large-scale industrial production of AP-3.

Abstract Background The Short Form-8 (SF-8) is a widely used instrument for measuring health-related quality of life (HRQOL). The purpose of the current study is to evaluate the reliability and validity of the Chinese version SF-8 using a large, representative sample of city residents in mainland China. Methods We surveyed residents of 35 major cities in China using random digit dialing of both landlines and cell phones. We adopted a multi-stage stratified sampling scheme and selected a probability sample of 10,885 adults. Internal consistency reliability of the SF-8 was evaluated with item-total correlations and Cronbach’s alphas. Construct validity was assessed with factor analysis. Known-groups validity was examined based on known HRQOL differences in age, gender, income, and overall quality of life. Results We showed that SF-8 has very good internal consistency reliability and known-groups validity. Our results also confirmed that the traditional 2-factor structure of SF-8 (physical and mental health) is reasonable among Chinese city residents. Further, we showed that a 3-factor model (physical, mental, and overall health) fit the data better than the traditional 2-factor model. Conclusions This study is the first to confirm the traditional 2-factor structure of SF-8 using a large, representative sample from China. We have shown that the SF-8 Chinese version is feasible, reliable, and valid. Our findings support the use of the SF-8 summary scores for assessing general HRQOL among Chinese. Future studies may further explore the possibility of a 3-factor structure for the SF-8 among the Chinese population.

Pre-exercise fluid intake is an important healthy behavior for maintaining athletes’ sports performances and health. However, athletes’ behavioral adherence to fluid intake and its underlying psychological mechanisms have not been investigated. This prospective study aimed to use a health psychology model that integrates the self-determination theory and the theory of planned behavior for understanding pre-exercise fluid intake among athletes. Participants (n = 179) were athletes from college sport teams who completed surveys at two time points. Baseline (Time 1) assessment comprised psychological variables of the integrated model (i.e., autonomous and controlled motivation, attitude, subjective norm, perceived behavioral control, and intention) and fluid intake (i.e., behavior) was measured prospectively at one month (Time 2). Path analysis showed that the positive association between autonomous motivation and intention was mediated by subjective norm and perceived behavioral control. Controlled motivation positively predicted the subjective norm. Intentions positively predicted pre-exercise fluid intake behavior. Overall, the pattern of results was generally consistent with the integrated model, and it was suggested that athletes’ pre-exercise fluid intake behaviors were associated with the motivational and social cognitive factors of the model. The research findings could be informative for coaches and sport scientists to promote athletes’ pre-exercise fluid intake behaviors.