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1.
Compared to data on adolescents and adults, limited research has been conducted on biological corre- lates among young children with possible psychological difficulties, especially in Asian countries. By focusing on various peripheral biochemical indicators, we investigated potential biological correlates of psychological states in a community sample of Taiwanese school children aged 6-10 years. In total, 307 students (159 obese children and 148 normal-weight children) were selected from first- and fourth-grade school children in eight elementary schools in the Taipei metropolitan area in 2009. These children underwent a comprehensive health examination, including a physical examination, blood sample analysis, and questionnaire administration in a hospital. Differences in anthropometric and serum biochemical readings were compared between children with average and worse levels on each of the five psychological domains. We found that interleukin (IL)-1β [β = 1.29, 95 % confidence interval (CI) 0.50-2.09], IL-10 (β = 1.61, 95 % CI 〈0.01-3.24), fasting blood glucose (β = 0.08, 95 % CI 0.01-0.15), homocysteine (β = 0.63, 95 % CI 0.09-1.18), and aspar- tate transaminase (AST) (β = 0.15, 95 % CI 〈0.01-0.31) were significantly positively associated with anxiety. In addition, IL-113, insulin, AST, and alanine aminotransam- inase (ALT) were significantly positively associated with depression. Anger and disruptive behaviors were also related to specific biological correlates. Specific biological correlates, including AST/ALT, cardiovascular disease- related variables, and specific cytokines, were linked to particular psychological states among young children in this Asian population. These might provide a route for better understanding the biological aspects of children's mental health and might contribute to research on diag- nostic or predictive biomarkers for psychiatric diseases in young children.  相似文献   

2.
Acetone is regarded as a promising biomarker for the noninvasive diagnosis and monitoring of diabetes.We collected breath acetone from 25 type 2 diabetics(T2D)and 44 healthy subjects using aluminum foil bags(3 L),and the samples were analyzed by gas chromatography–mass spectrometry.T2D patients had significantly higher acetone levels(mean=2.167 ppmv(1 ppmv=1 lL/L),standard error(SE)=0.231)than healthy volunteers(mean=0.488 ppmv,SE=0.025;P\0.0001).The receiver operating characteristics curve showed that the optimum diagnostic cutoff value for exhaled acetone was 0.891 ppmv(area under the curve 0.999,sensitivity 100%,and specificity 97.7%)in T2D patients relative to healthy subjects.Thus,breath acetone could be a useful marker for the high accuracy diagnosis and monitoring of diabetes.In addition,the ratios of the mean acetone concentration in ambient air relative to that in the total exhaled air and in the net exhaled air were 1:18 and 1:17,respectively.The post-breakfast acetone concentrations(mean=0.437 ppmv,SE=0.035)were slightly lower than the pre-breakfast levels(mean=0.553 ppmv,SE=0.047;P[0.05).Thus,the increased acetone concentrations in T2D patients are affected strongly by physiological factors related to the disease,rather than the ambient air and diet.  相似文献   

3.
Understanding the stressor–response relationship between nutrient levels and algal biomass is a prerequisite for the management of eutrophication in lakes. In this study, a quantile regression(QR) approach was used to interpret the stressor–response relationships between nutrient(e.g., phosphorus, nitrogen) concentrations and algal biomass as measured by chlorophyll-a(Chl-a) levels. QR results indicated that Lake Dianshan and Lake Changdang,which are both heavily eutrophicated, were P-limited only.In contrast, Lake Kuilei, which has significantly lower nutrient levels and algal biomass than the other two lakes,was P- and N-limited. Moreover, in Lake Kuilei, N and P levels had significant interaction effects on the algal biomass at the upper quantiles(s [ 0.68). The degree to which the lakes were P-limited increased with rises in the mean total P concentration in the lakes. QR has many advantages over ordinary least squares regression for discriminating limiting factors and, in particular, allows us to estimate changes near the upper extremes of distributions associated with limiting factors. QR is adapted to more specialized risk management problems, such as early warnings of the risk of algal blooms.The probable value-at-risk of harmful algal blooms for Lake Kuilei, Lake Dianshan and Lake Changdang is s = 0.76(Chl-a = 9 mg/m3), s = 0.87(Chl-a = 24 mg/m3) and s = 0.72(Chl-a = 35 mg/m3), respectively. Given the results of the stressor–response relationship analysis, we conclude that reductions in P input represent the most feasible and least costly approach for managing eutrophication in the shallow lakes of the Lake Taihu Basin. To control the magnitude and duration of algal blooms in shallow lakes,reductions in P and N inputs are required. The 95 % CI bounds of slopes indicated that the interactions of nonnutrient factors with nutrients had strong impacts on the algal biomass in lightly eutrophicated Lake Kuilei. It is suggested that, in addition to reductions in nutrient loads,several ecological measures, such as an increase in the biomass of submerged macrophytes and the reduction of hydraulic retention time by flushing, could represent important components of an integrated approach to eutrophication management in the Lake Taihu Basin.  相似文献   

4.
The trend of fencing grassland as livestock paddocks is spreading on the Eurasian steppe,however,its impacts on grassland wildlife are little known.In order to explore such impacts,we carried out a field study on how grassland fencing impacts Przewalski’s gazelle(Procapra przewalskii),a species listed as EN(Endangered) by SSC/IUCN,on the Qinghai-Tibet Plateau.The results revealed that(1) in the fenced areas,daily movement distance of Przewalski’s gazelle was 5081±1187 m(Hudong-Ketu) and 4110±912 m(Yuanzhe),which was much shorter than the 7223±546 m recorded in an unfenced area(Kuaierma);(2) the feeding bout duration of Przewalski’s gazelle was much shorter in the fenced habitat;(3) the frequency of walking along both high or low fence lines reached about 81%;while the frequency of jumping across the low fence line was only about 1.2% and frequency of crawling through the bottom of the high fence lines was about 17.8%;(4) the size of post-fencing habitat decreased to about 20% and 6% of the sizes of pre-fencing habitat in Hudong-Ketu and Yuanzhe areas respectively,but no clear change in the size of habitat area was found in the unfenced Kuaierma area;and(5) the fence lines impaired the possibility of gazelles to escape from predators and occasionally trapped the Przewalski’s gazelle which failed to jump over the fence lines.Death occurrence of Przewalski’s gazelle in the intensively fenced area,including gazelles strangled by fence lines and predated by wolves,reached 5% of the population size in Yuanzhe and up to 15%-20% in Hudong-Ketu.This study highlights the negative impacts of grassland fencing on Przewalski’s gazelle and proposes measures for integrating conservation of this gazelle with livestock management practice.  相似文献   

5.
A novel phenol-linked bis(imidazolium) salt, H3LCl2 (L = O-4-C(CH3)3-C6H2-2,6-di[CH2{C(NCHCH- NAr)}]2, Ar = 2,6-diisopropylphenyl, 1), was designed and used to prepare an ionic iron(III) complex [H2L][FeCl4] (2). Complex 2 was a highly efficient catalyst for aryl Grignard cross-coupling of alkyl chlorides bearing β-hydrogens. Furthermore, complex 2 was reusable and could be reused in at least eight times without significant loss in catalytic activity.  相似文献   

6.
实时预测民航发动机滑油量对保障飞行安全具有重要意义.针对滑油量受发动机多个工作状态的多个参数影响,具有影响参数多,提取方法不确定等问题,提出了一种基于邻域粗糙集(neighborhood rough set,NRS)和灰狼优化(grey wolf op-timizer,GWO)-Elman相结合的方法预测滑油量.首先通过邻域粗糙集提取对滑油量重要度高的发动机工作阶段,将提取后的工作阶段有关参数作为特征向量输入到灰狼优化-Elman的网络模型中,灰狼算法通过计算和比较个体的适应度来优化El-man网络中的权值和阈值,保证Elman网络中的权值和阈值达到全局最优.预测结果表明,精度达到98.44%,满足工程应用的精度要求.研究结果为及时监测民航发动机滑油系统的健康状况提供理论依据.  相似文献   

7.
李靖  杨帆 《科学技术与工程》2020,20(15):6122-6129
为了解决大任务量作业监测中机器人路径规划问题,提出了一种区域监测的机器人路径规划算法。模拟大任务量监测真实环境进行问题建模。针对传统灰狼优化算法求解模型时全局搜索能力差且易陷入局部最优解的问题,提出了一种改进的灰狼优化算法。引入Logistic混沌映射,以加强初始化种群的多样性;引入一种控制参数的自适应调整策略,以平衡灰狼优化算法的搜索能力和开发能力;引入静态加权平均权重策略,更新种群位置,加快收敛速度。将机器人载电量与路径长度短作为约束,引入K-means算法进行任务聚类,通过改进灰狼优化算法对模型进行离线求解以规划出路径,将大任务量监测作业自动转换成分时分步作业。实验结果表明:通过国际通用6个基准函数进行测试,改进的灰狼优化算法在收敛速度、搜索精度及稳定性上均有明显提高。通过50任务点与100任务点作业场景对机器人路径规划模型进行算法仿真,验证了算法的真实有效性,且任务量越大模型优越性越好,路径缩短比例越高。  相似文献   

8.
Inorganic arsenic(iAs) at high doses is a known human carcinogen, inducing tumors of the skin,urinary bladder, and lung. It is also associated with noncancer toxicities. An understanding of the mode of action(MOA) for arsenic-induced effects is needed to develop a scientifically-based risk assessment. To determine an MOA for iAs induced toxicities, it is necessary to understand the metabolism, kinetics, cell transport, and interaction with specific proteins of iAs. Based on in vitro investigations using animal and human cells, studies from animal models,and clinical and epidemiological studies, we have proposed an MOA involving formation of sufficient levels of reactive trivalent metabolites which interact with critical free sulfhydryl groups, leading to cytotoxicity and regenerative cell proliferation. There is a strong correlation between in vitro cytotoxicity([0.1 lmol/L trivalent arsenicals) and the no effect levels in rodents [approximately 1 ppm(1 ppm = 1 mg/L) of water or diet]. In epithelial target tissues, the cytotoxic effects of iAs result in chronic precursor lesions which have the potential for an increased risk of developing cancer. In non-epithelial tissues, noncancer toxicities such as hypertension and atherosclerosis develop. This MOA implies a non-linear, threshold dose–response relationship for both non-cancer and cancer end points of exposure to iAs.  相似文献   

9.
This study demonstrates the accuracy of powder X-ray diffraction (PXRD) in determining the crystal structures of four organic molecules by comparing the structural information obtained from both single-crystal X-ray diffraction (SXRD) and PXRD techniques. Results showed that the PXRD technique had approximately the same precision as the SXRD technique. The majority of the relative deviations from PXRD-derived lattice parameters were within ±0.2 % of the correct values (average of the SXRD data), whereas the relative deviations in bond lengths and angles are within ±1.0 %. All of the relative deviations were subjected to normal statistical distributions (μ = 0) and coincided with the SXRD data. As an auxiliary implement of SXRD, PXRD is clearly an effective and powerful technique in establishing an accurate characterization of organic molecules.  相似文献   

10.
Through petrography, mineral compositions and P-T estimate results, an ultrahigh-temperature(UHT) metapelitic granulite has recently been identified from near Kalasu in the east of Altay city, with an assemblage gt-opx-silcd-sp-bt-pl-qtz. The orthopyroxene has a high-Al feature, and its Al2O3 content is as high as 8.7 wt%, indicating a UHT metamorphic condition. Its peak metamorphic condition is estimated as: P = *0.80 GPa, T = *960 °C. Metamorphic textural relations and P-T estimate results show a post-peak near-isobaric cooling anticlockwise P-T path. Zircon U-Pb age results(271 ± 5 Ma) support that the UHT metamorphic event in the region occurred in the Permian. The identification of the UHT metapelitic granulite from near Kalasu confirms the existence of the Permian UHT metamorphism in the Altay orogen, implying that the Permian extensional tectonic setting of a high-heat flow in the southern part of the Altay orogen may be closely associated with the Permian Tarim mantle plume activity.  相似文献   

11.
The association of circulating levels of cystatin C (CysC) and risk of recurrent cardiovascular events in patients with preexisting coronary heart disease are uncertain. To qualitatively and quantitatively address this issue, we performed a random meta-analysis of results from prospective studies on the topic. We searched electronic and printed sources (up to 16 October 2011) using keywords and retrieved articles for seven prospective studies according to the selection criteria. Data were abstracted and meta-analysis was performed using the random-effects model (RevMan 5.0.23 software). The cohorts involved 4,576 patients with preexisting coronary heart disease (CHD) and normal or mild chronic kidney disease, and follow-up ranged from 5.6 to 40.6 months. Highest versus lowest baseline CysC level was significantly associated with increased risk of cardiovascular events (OR 2.30, 95 % CI 1.80–2.94), all-cause mortality (OR 5.69, 95 % CI 3.70–8.74), but not with recurrent MI (OR 1.75, 95 % CI 0.77–4.00). In heterogeneity testing for studies reporting cardiovascular events and all-cause mortality, no significant heterogeneity was found, and exclusion of any single study did not alter the overall finding. For risk of recurrent MI, significant heterogeneity was found among the five trials (χ 2 = 13.16, P = 0.01, I 2 = 70 %) and exclusion of the Taglieri et al. [12] study from the analysis resulted in a rise in relative risk (OR 2.36, 95 % CI 1.09–5.15). In conclusion, for patients with established CHD, high baseline level of CysC is associated with increased risk of cardiovascular events and all-cause death during long-term follow-up.  相似文献   

12.
Eight new Palaeolithic open-air sites were identified and 770 stone artefacts were collected from 2009 to 2011 in the Lantian area of the Bahe River valley, central China. Because the famous Homo erectus fossils were unearthed at the Gongwangling and Chenjiawo localities, and more than 30 Palaeolithic open-air sites were investigated in the 1960s in this region, the catchment of Bahe River is regarded as one of the most important hominin sites from the late early Pleistocene to the middle Pleistocene. These eight newly discovered open-air sites are located at the second(n = 6), third(n = 1) or higher terraces(n = 1) of the Bahe River. The Diaozhai section on the second terrace was sampled in detail. Two samples were collected for optically stimulated luminescence dating(OSL). The OSL results suggest that a buried lithic artefact layer at the Diaozhai site spans approximately 70–30 ka. The lithic assemblage analysis suggests that the stone artefacts were made of local pebbles/cobbles such as greywacke, quartz, sandstone and igneous rocks. The main percussion techniques that were used were direct hard hammer percussion and bi-polar techniques. The lithic artefacts comprise hammer stones, cores, flakes, retouched tools and flaking debris. Acheulian-type large cutting tools(LCTs) such as hand-axes, picks and cleavers were indentified in the Lantian region as well. This is the first time Acheulian-type LCTs from the late Pleistocene have been identified in this region. This study distinguishes age gaps between Western world and East Asian Acheulian-type tools.  相似文献   

13.
The Weather Research and Forecasting model(WRF)is configured for the region of(15°–41°N,105°–135°E),which covers the same area with the MASNUM(Key Lab.Marine ScienceNumerical Modeling,State Oceanic Administration)wave-tide-circulation coupled operational forecast system.Three numerical experiments are implemented to investigate the effects of the real-time forecasted sea surface temperature(SST)and the nonbreaking wave-induced vertical mixing(Bv)on the track forecast of all 33 tropical cyclones(TC)in the model domain area during 2008 and 2011.The first experiment employs NCEP FNL(NCEP final analysis)SST as WRF’s bottom condition as the Control run,which is also the default setup of WRF.The second and third experiments use real-time forecasted SST from the MASNUM forecast system with and without Bv,respectively.The forecasted track results are compared with Japan Meteorological Agency’s best track data.For 24-h forecast,the averaged TC position error of Experiment with Bv is reduced by 9%compared to the Control experiment,while the forecasted track error of Experiment without Bv is reduced by only2%compared to the Control experiment.For the 48-h forecast,the averaged track errors are reduced by 10%and6%with Bv and without Bv compared to the Control experiment,respectively.These results suggest that the real-time forecasted SST can improve the performance of WRF in forecasting TC track,and the Bv plays an important role in reducing the forecast error of TC track.Comparatively,Bv can improve more on the track of stronger TC.  相似文献   

14.
This study analyzes the changes in glacier zones and snow composition of Glacier No.1 in the Tianshan Mountains of China since 1961,and their possible relations with climate.It is found that precipitation dominated the snow composition and that air temperature and precipitation controlled the distribution of glacier zones,but interannual change in precipitation had a relatively large effect on glacier zones and snow composition during 1963–1981 (P10) and 1963–1989 (P11).However,during 1982–2007 (P20) and 19...  相似文献   

15.
El Nio-Southern Oscillation(ENSO)has affected penguins and their habitats in the western Antarctic Peninsula.We used both historical penguin population dynamics data(1980–2012)and sedimentary lipids in penguin droppings(1916–2001)on Ardley Island to examine the responses of the Antarctic ecosystem to ENSO(El Nin o/La Nin a)events.The results showed that during the last 30 years,climate,marine food chain changes,and human activity have significantly affected penguin population sizes on Ardley Island.The Chinstrap(Pygoscelis antarctica)and Ade′lie(P.adeliae)penguin populations showed a good correlation with ENSO events.The Chinstrap penguin population decreased significantly because it was more sensitive to increasing human disturbance(e.g.,scientific activity and tourism)than Ade′lie and Gentoo(P.papua),particularly during the breeding season.Compositional features of n-alkanes in penguin dropping sediments revealed that organic matter came from lower terrestrial plants,bacteria and algae.C23was the main nalkane heavy hydrocarbon indicating mosses and lichens in the penguin’s diet.Variation in the ratio of nC23/nC17was closely correlated with ENSO events.The bacteria intrusion index(ratio of(iC15:0?aC15:0)/nC15:0for fatty acids)reflected significant increases in microorganism activity during several periods in this area.Meanwhile,the CPIA value for fatty acids decreased because micro-organisms contributed light hydrocarbon fatty acids to penguin droppings.Our results showed that the fine structure and molecular indices of fatty acids and n-alkanes in penguin dropping sediments can be used to explain climate-driven microbial processes,and to reveal the important role that microbes and bacteria play in the relatively simple Antarctic ecosystem.  相似文献   

16.
针对基本灰狼算法存在初始种群不均匀、早熟收敛等问题,基于混沌理论从三个方面对灰狼优化(grey wolf optimization, GWO)算法进行改进,提出了混沌灰狼优化(chaotic grey wolf optimization,CGWO)算法用于确定边坡的最小安全系数.首先,采用改进Tent混沌映射提高初始种群多样性;其次,通过混沌扰动策略避免算法陷入局部最优;最后,引入参数混沌非线性调节机制均衡算法的全局开发和局部勘探算力.13个基准测试函数的仿真结果表明,改进后的算法与基本GWO,WOA,PSO以及SCA相比具有更强的综合寻优性能.选取ACADS边坡考核题进行计算分析,CGWO算法表现出较高的计算精度和收敛速度,能够有效地搜索到复杂分层边坡的最小安全系数.对比有限元强度折减法,该方法具有操作简易、搜索区域易于设置等优点.  相似文献   

17.
Magnetocardiography(MCG) has been investigated as a tool for noninvasive detection of coronary artery disease(CAD). In this study, the area ratio of positive and negative magnetic induction extracted from an extrema circle in the magnetocardiogram was analyzed at specific time points in the cardiac cycle: P maximum, R peak, J point, T onset, T peak and T end. The area of the positive proportion of the magnetic field relative to the total area within a circle encompassing the field extrema was determined and proposed for fast-speed CAD diagnosis. MCG was performed with a 61-channel biomagnetometer in a shielded environment in 38 healthy subjects and 15 CAD patients. A notable difference in area ratio was found between healthy and CAD subjects at the peak time of T wave: 0.416 ± 0.090 versus0.465 ± 0.065(p = 0.013). Using a cutoff value of 0.4506resulted in a sensitivity and specificity of 86.7 % and 73.8 %,respectively. This approach may enable a fast-speed CAD diagnosis in a clinical setting.  相似文献   

18.
Crystal structure determining of 7-ADCA based on X-ray powder diffraction   总被引:2,自引:0,他引:2  
Traditionally, crystal structure data can be collected and determined from single-crystal X-ray diffraction. However, in the fields of organic and macromolecular crystallography, it is often difficult or impractical to grow single crystals with suitable sizes and purity. Therefore, it will be benefited from the newly growing analytical tool that combining X-ray powder diffraction based on polycrystalline samples and ab initio calcula- tion[1]. 7-ADCA is one of the most important intermediate…  相似文献   

19.
A hierarchical cluster analysis has been made on the geomagnetic and geoelectric data of Nagoya (ϕ=21. 1°), Japan (1978–1981, 1985, 1987) and geomagnetic data of Wuchang (ϕ=19. 1°), China (1985–1995). From the cluster diagram it is seen that the monthly mean occurrence of Pc3–4 observed at these two sites can be best grouped into 3 clusters. Supported by the National Natural Science Foundation of China Zhao Zhengyu: born in 1952, Doctor, Associate professor  相似文献   

20.
百里杜鹃国家森林公园优势种生态位研究   总被引:1,自引:0,他引:1  
【目的】评估百里杜鹃国家森林公园杜鹃花科优势种的资源利用能力和空间占据能力,为经营管理提供依据。【方法】应用生态位宽度、生态位相似度及Pianka生态位重叠度计算方法,对百里杜鹃优势种群生态位特征进行研究。【结果】①群落中杜鹃花科植物(马樱杜鹃、露珠杜鹃、迷人杜鹃、映山红)生态位宽度较大,分别为1.709、1.576、1.411、1.062,是群落的优势种; ②该群落种群间的生态位相似性比例较小,生态位宽度与生态位相似性之间无显著关系; ③生态位宽度大的物种与其他物种发生重叠的概率更大,但生态位重叠值不一定大。【结论】杜鹃花科植物在群落中生态位宽度较大,而马缨杜鹃与露珠杜鹃的生态位重叠程度在降低,这主要与植物的生物-生态学特性有关,是种群对资源利用的长期适应性结果。  相似文献   

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