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1. chinaXiv:202101.00068 [pdf]

同伴对青少年冒险行为的影响及其作用机制

张玮玮; 朱莉琪
Subjects: Psychology >> Developmental Psychology

青少年更倾向于从事冒险或鲁莽行为,并且更容易受到同伴影响。从个人特质和社交互动等多个角度探讨的研究结果表明,同伴对青少年冒险行为存在助长作用,即当同伴在场时,青少年的行为会更加冒险。同伴对青少年冒险行为的作用机制可以从心理、神经、遗传、社会文化等多个层面进行解释:在心理层面,这种影响源于青少年寻求同伴认可和归属感的需要,以及社会学习的作用;在神经机制层面,源于认知控制网络和刺激处理系统的相互作用;在遗传层面,源于特定基因的易感性等;在社会文化层面,同伴影响会因文化差异而带来程度与表现上的差异。未来研究应从发展、文化心理、构建复杂模型网络等视角深入探究同伴对青少年冒险行为的影响。

submitted time 2021-01-19 Hits21Downloads13 Comment 0

2. chinaXiv:202101.00067 [pdf]

基于最优供需分配的公共设施空间可达性分析

孔云峰
Subjects: Geosciences >> Geography

空间可达性是衡量公共服务设施公平性的重要指标,在医疗、教育、休闲等公共服务的布局规划中得到广泛应用。然而,现有可达性模型难以充分反映服务供需关系,计算指标也缺乏物理意义。本文提出新的可达性计算方法取代现有方法。该方法基于最优供需分配模型,将设施服务分配给需求者,根据分配结果计算空间可达性指标。给定服务设施与需求的空间分布,以最小化旅行成本为目标,顾及设施服务能力,采用经典的运输问题模型确定最优的服务供需分配方案,进而度量服务的空间可达性。以郑州市某区社区卫生服务为例,求解 25个中心与1333个居住小区的最优服务配置。使用最优配置结果确定每个设施的服务范围、每个居住小区使用服务的旅行时间,以及特定时间阈值的服务覆盖比率。与流行的两步移动搜索法相比,新方法的计算指标具有明确的物理意义。本文提出的可达性评价方法无需参数,计算高效,结果易于解释,在公共服务评价及设施布局规划方面具有应用潜力。

submitted time 2021-01-19 Hits18Downloads12 Comment 0

3. chinaXiv:202101.00065 [pdf]

人类发音起源和演化研究综述

孔江平,吴西愉
Subjects: Linguistics and Applied Linguistics >> Linguistics and Applied Linguistics

本文详细地梳理了人类语音起源和演化的研究成果,为对语音起源和演化感兴趣的学者和研究生提供了大量有关的研究文献,并对前人在这个领域里的研究进行了初步的评述。

submitted time 2021-01-18 Hits46Downloads25 Comment 0

4. chinaXiv:202101.00064 [pdf]

成员关系对协作提取成绩的影响

张环; 王欣; 刘一贝; 曹贤才; 吴捷
Subjects: Psychology >> Cognitive Psychology

当人们与搭档组成社会群体一起协作讨论某些已经发生的事件或经验时,该社会群体中的成员关系对协作提取成绩的影响仍不明确。本研究通过两项实验,分别使用语词词单和情景故事作为实验材料,考察成员关系(关系类型和关系时长)对协作提取成绩的影响。研究结果表明,当记忆的材料为语词词单时,青年陌生组出现了协作抑制;而当记忆的材料为情景故事时,青年夫妻和老年夫妻组均出现了协作促进。此外,老年夫妻在协作提取情景故事的过程中使用的有效交流策略更多,且这些有效交流策略的使用与更高的协作提取成绩有关。该结果支持了具有长时亲密关系的老年夫妻之间“交互记忆系统”对协作促进的关键作用,为理解成员关系对协作提取成绩的影响提供了全面的证据。

submitted time 2021-01-18 Hits46Downloads17 Comment 0

5. chinaXiv:202101.00045 [pdf]

Spectral parameter-based models for leaf potassium concentration estimation in Ping'ou hybrid hazelnut

ZHAO Shanchao; PAN Cunde
Subjects: Geosciences >> Geography

Ping′ou hybrid hazelnut is produced by cross cultivation and is widely cultivated in northern China with good development prospects. Based on a field experiment of fertilizer efficiency, the leaf spectral reflectance and leaf potassium (K) concentration were measured with different quantities of K fertilizer applied at four fruit growth stages (fruit setting stage, fruit rapid growth stage, fruit fat-change stage, and fruit near-maturity stage) of Ping′ou hybrid hazelnut in 2019. Spectral parameters that were significantly correlated with leaf K concentration were selected using Pearson correlation analysis, and spectral parameter estimation models of leaf K concentration were established by employing six different modelling methods (exponential function, power function, logarithmic function, linear function, quadratic function, and cubic function). The results indicated that at the fruit setting period, leaf K concentration was significantly correlated with Dy (spectra slope of yellow edge), Rg (reflectance of the green peak position), λo (red valley position), SDb (blue edge area), SDr/SDb (where SDr represents red edge area), and (SDr–SDb)/(SDr+SDb) (P<0.01). There were significant correlations of leaf K concentration with Dy, Rg, SDb, Rg/Ro (where Ro is the reflectance of the red valley position), and (Rg–Ro)/(Rg+Ro) at the fruit rapid growth stage (P<0.01). Further, significant correlations of leaf K concentration with Rg, Ro, RNIR/Green, and RNIR/Blue were obtained at the fruit fat-change period (P<0.01). Finally, leaf K concentration showed significant correlations with Dr, Rg, Ro, SDy (yellow edge area), and SDr at the fruit near-maturity stage (P<0.01). Through a cubic function analysis, regression estimation model of leaf K concentration with highest fitting degree (R2) values at the four fruit growth stages was established. The findings in this study demonstrated that it is feasible to estimate leaf K concentration of Ping′ou hybrid hazelnut at the various phenological stages of fruit development by establishing regression models between leaf K concentration and spectral parameters.

submitted time 2021-01-15 From cooperative journals:《Journal of Arid Land》 Hits26Downloads6 Comment 0

6. chinaXiv:202101.00046 [pdf]

Germination strategies of annual and short-lived perennial species in the Arabian Desert

Arvind BHATT; David J GALLACHER; Paulo R M SOUZA-FILHO
Subjects: Geosciences >> Geography

Germination timing is highly regulated in short-lived plant species since it strongly influences recruitment success of vegetation. In deserts, the spatiotemporal distribution of plant-available water is highly episodic and unpredictable, making winter months more favorable for seed germination when other abiotic conditions co-occur. We hypothesized that changes in photoperiod and thermoperiod would impact germination more in seeds that had undergone in situ storage. We assessed 21 annual and short-lived perennial species in the Arabian Desert to find (1) if seeds were dormant at maturity, (2) if in situ seed storage increased germination percentage compared with no storage, (3) if photoperiod and thermoperiod germination requirements were influenced by in situ storage, and (4) if a phylogenetic association in seed germination could be observed. Seeds of each species collected in early 2017 were divided into two batches. One was tested for germination within one week (fresh seeds). The other was stored in situ at the maternal location (stored seeds) until October 2017 and tested for seed germination in the first week of November. Seed germination was conducted in incubators at two thermoperiods (15°C/20°C and 20°C/30°C; 12 h/12 h), and two photoperiods (12 and 0 h light per day). Results indicated that seed germination percentages of 13 species were significantly enhanced by in situ storage. A thermoperiod response was exhibited by stored, but not fresh seeds. Light exposure increased germination of fresh seeds but had only a minimal effect on stored seeds. Germination traits exhibited no phylogenetic correlation. This result indicated that selection pressure for germination strategy was stronger than that for taxonomic traits of these desert species.

submitted time 2021-01-15 From cooperative journals:《Journal of Arid Land》 Hits31Downloads9 Comment 0

7. chinaXiv:202101.00047 [pdf]

基于双DKDP晶体原理的太阳大气实时偏振探测技术研究

胡平; 顾乃庭; 饶长辉
Subjects: Astronomy >> Astrophysical processes

磁场是太阳爆发活动的根本驱动力,高精度实时偏振测量是实现磁场测量的常用方法。然而常用的波片式测量方法需要进行多次测量,且存在机械旋转结构,易导致仪器抖动,降低测量精度;波片旋转或切入切出也会导致测量时间较长。目前,基于DKDP晶体和波片的太阳大气偏振测量周期较长,实时性不高,无法应用于快速变化的太阳活动磁场探测。基于以上背景,本论文提出了一种基于双DKDP晶体原理的太阳大气实时偏振探测技术,采用两片快轴方向不同的DKDP晶体,通过外加不同电压进行快速相位延迟变化,实现对入射太阳光的偏振调制,获取太阳大气偏振斯托克斯矢量。相较于传统旋转波片与DKDP晶体相结合的方法,本论文提出方法可将单次偏振调制速率从数秒提升到毫秒级,极大地提升了太阳磁场测量实时性。仿真分析结果表明:本文提出方法测量精度达到2×〖10〗^(-3),单波长点测量时间分辨率提升了20倍以上,可以实现对太阳磁场偏振信息的实时精确测量。

submitted time 2021-01-15 From cooperative journals:《天文研究与技术》 Hits30Downloads8 Comment 0

8. chinaXiv:202101.00048 [pdf]

Effects of different loading rates and types of biochar on passivations of Cu and Zn via swine manure composting

CHEN Yan; XU Yongping; QU Fangjing; HOU Fuqin; CHEN Hongli; LI Xiaoyu
Subjects: Geosciences >> Geography

Pollution of arable land caused by heavy metals in livestock and poultry manure has become a potential threaten to human health in China. Safe disposal of the contained toxic pollution with animal manure by co-composting with biochar is one of the alternative methods. Biochars from different sources (wheat straw, peanut shells and rice husks) amended with different loading rates were investigated for passivations of copper and zinc (Cu and Zn) in swine manure composting. Results showed that the passivation effects of the three types of biochar on Cu and Zn were enhanced with increasing biochar dose. Contents of Cu and Zn measured by diethylenetriaminepentaacetic acid (DTPA) and Community Bureau of Reference (CBR) showed that wheat straw biochar with the loading rates of 10%–13% (w/w) was superior to the other two types of biochar in this study. Compared with the control, sample from wheat straw biochar was more favorable for the bacterial growth of Proteobacteria, Firmicutes and Actinobacteria. In addition, pot experiment showed that organic fertilizer amended with wheat straw biochar could significantly improve the growth of Chinese pakchoi and enzyme activities (superoxide dismutase, peroxidase, polyphenol oxidase and catalase) as compared with the control. Cu and Zn contents of Chinese pakchoi in the organic fertilizer group containing wheat straw biochar reduced by 73.2% and 45.2%, 65.8% and 33.6%, respectively, compared with the group without loading biochar. There was no significant difference in the contents of vitamin C and reducing sugar between the groups of organic fertilizer amended with/without wheat straw biochar, however, there was significant difference compared with the heavy metal addition group. The application of organic fertilizer formed by adding biochar can effectively reduce the adverse effects of heavy metals on crops.

submitted time 2021-01-15 From cooperative journals:《Journal of Arid Land》 Hits22Downloads5 Comment 0

9. chinaXiv:202101.00049 [pdf]

Improving wood volume predictions in dry tropical forest in the semi-arid Brazil

Robson B de LIMA; Patrícia A B BARRETO-GARCIA; Alessandro de PAULA; Jhuly E S PEREIRA; Flávia F de CARVALHO; Silvio H M GOMES
Subjects: Geosciences >> Geography

The volumetric variability of dry tropical forests in Brazil and the scarcity of studies on the subject show the need for the development of techniques that make it possible to obtain adequate and accurate wood volume estimates. In this study, we analyzed a database of thinning trees from a forest management plan in the Contendas de Sincorá National Forest, southwestern Bahia State, Brazil. The data set included a total of 300 trees with a trunk diameter ranging from 5 to 52 cm. Adjustments, validation and statistical selection of four volumetric models were performed. Due to the difference in height values for the same diameter and the low correlation between both variables, we do not suggest models which only use the diameter at breast height (DBH) variable as a predictor because they accommodate the largest estimation errors. In comparing the best single entry model (Hohenald-Krenn) with the Spurr model (best fit model), it is noted that the exclusion of height as a predictor causes the values of 136.44 and 0.93 for Akaike information criterion (AIC) and adjusted determination coefficient (R2 adj), which are poorer than the second best model (Schumacher-Hall). Regarding the minimum sample size, errors in estimation (root mean square error (RMSE) and bias) of the best model decrease as the sample size increases, especially when a larger number of trees with DBH≥15.0 cm are randomly sampled. Stratified sampling by diameter class produces smaller volume prediction errors than random sampling, especially when considering all trees. In summary, the Spurr and Schumacher-Hall models perform better. These models suggest that the total variance explained in the estimates is not less than 95%, producing reliable forecasts of the total volume with shell. Our estimates indicate that the bias around the average is not greater than 7%. Our results support the decision to use regression methods to build models and estimate their parameters, seeking stratification strategies in diameter classes for the sample trees. Volume estimates with valid confidence intervals can be obtained using the Spurr model for the studied dry forest. Stratified sampling of the data set for model adjustment and selection is necessary, since we find significant results with mean error square root values and bias of up to 70% of the total database.

submitted time 2021-01-15 From cooperative journals:《Journal of Arid Land》 Hits23Downloads5 Comment 0

10. chinaXiv:202101.00050 [pdf]

Mapping the current and future distributions of Onosma species endemic to Iran

Farzaneh KHAJOEI NASAB; Ahmadreza MEHRABIAN; Hossein MOSTAFAVI
Subjects: Geosciences >> Geography

Climate change may cause shifts in the natural range of species especially for those that are geographically restricted and/or endemic species. In this study, the spatial distribution of five endemic and threatened species belonging to the genus Onosma (including O. asperrima, O. bisotunensis, O. kotschyi, O. platyphylla, and O. straussii) was investigated under present and future climate change scenarios: RCP2.6 (RCP, representative concentration pathway; optimistic scenario) and RCP8.5 (pessimistic scenario) for the years 2050 and 2080 in Iran. Analysis was conducted using the maximum entropy (MaxEnt) model to provide a basis for the protection and conservation of these species. Seven environmental variables including aspect, depth of soil, silt content, slope, annual precipitation, minimum temperature of the coldest month, and annual temperature range were used as main predictors in this study. The model output for the potential habitat suitability of the studied species showed acceptable performance for all species (i.e., the area under the curve (AUC)>0.800). According to the models generated by MaxEnt, the potential current patterns of the species were consistent with the observed areas of distributions. The projected climate maps under optimistic and pessimistic scenarios (RCP2.6 and RCP8.5, respectively) of 2050 and 2080 resulted in reductions and expansions as well as positive range changes for all species in comparison to their current predicted distributions. Among all species, O. bisotunensis showed the most significant and highest increase under the pessimistic scenario of 2050 and 2080. Finally, the results of this study revealed that the studied plant species have shown an acute adaptability to environmental changes. The results can provide useful information to managers to apply appropriate strategies for the management and conservation of these valuable Iranian medicinal and threatened plant species in the future.

submitted time 2021-01-15 From cooperative journals:《Journal of Arid Land》 Hits15Downloads3 Comment 0

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