首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
The association between circadian preference and academic achievement has been assessed through a systematic review and meta-analysis. The literature searches retrieved 1647 studies; 31 studies, with a total sample size of 27?309 participants, fulfilled the inclusion criteria and were included in the meta-analysis. With reference to all these 31 studies, before running the meta-analysis, the sign of the correlation between the investigated variables was set in a way that a positive correlation showed that eveningness was related to worse academic performance. The meta-analysis yielded a small overall effect size of 0.143 (CI [0,129; 0,156]) under a fixed effects model (Z?=?20.584, p?<?0.001, I2?=?72.656; Q?=?109.715) and of 0.145 (CI [0.117; 0.172]) under a random effects model (Z?=?10.077, p?<?0.001). A random effects model with a grouping variable (participants) revealed 15 studies based on school pupils and 16 on university students. The random model showed a higher effect size in school pupils (0.166, CI from 0.127 to 0.206) compared to university students (0.121, CI from 0.080 to 0.163). Self-report measures of grades revealed a stronger effect size (0.171; CI: 0.137 to 0.206; N?=?20) compared to objective measures (0.093; CI: 0.047 to 0.140; N?=?19). Overall, the present results suggest that evening orientation is associated with a worse academic performance, both in school pupils and university students; for the first time, it has been shown that such relationship changes over time, being weaker in university students.  相似文献   

2.
王玉  傅碧天  吕永鹏  杨凯  车越 《生态学杂志》2016,27(6):1767-1774
人类活动对生态系统不同服务的多样化需求日益增长,传统的生态系统服务价值评估实践多以经济学方法为主,较少关注社会属性和空间异质性.本文选取上海市吴淞炮台湾湿地森林公园作为研究对象,采用SolVES模型对其美学、生物多样性、文化、娱乐等服务的社会价值进行量化和空间分析.结果表明: 公园的热点区域集中在草坪乐园、吴淞炮台纪念广场、临江观景台等视野开阔或临近水景观的区域;游客对公园内美学、历史、生物多样性、娱乐、文化、康体健身价值较为偏好;水景观和路网布局影响游客对不同社会价值的偏好程度,美学、生物多样性、娱乐和康体健身价值高低与距水体远近在一定范围内呈显著负相关关系,美学和康体健身价值高低与距道路远近呈显著负相关关系;游憩频率影响游客对生物多样性价值和康体健身价值的感受及偏好;SolVES模型在评估中小尺度生态系统服务社会价值方面具有较好的可行性.  相似文献   

3.
It is generally recognised that indicator-based research forms a substantial part both of the everyday practice and of the current theoretical pursuits in an extensive set of different scientific fields that relate to the socio-economic and the environmental sphere. However, the lack of an endogenous indicator's theory hinders the enhancement of indicator's research into an autonomous scientific field and subdues the indicators study to the broader ecological, social, or economic context. Thus, scientists are often bounded to the study of indicators within their specialisation area, as evidenced by the very limited number of interdisciplinary studies on the use of indicators that have been published. Based on this deficiency of the current literature, the paper elaborates on the use of indicators in the socio-economic and the environmental area, focusing on fields in which indicators are essential to their practice. Namely, the paper reviews quality-of-life, macroeconomic, environmental, welfare and sustainability indicators in order to detect similarities and differences, pertain to their practice and to the theoretical frameworks in which indicators are utilised. The study concludes that quality-of-life, welfare and sustainability indicators are supported by weak theoretical foundations, as a result to the choice of the respective fields to exploit the possible benefits of an empirical interdisciplinary perspective, a fact that leads the use of indicators to methodological inconsistencies. In contrast, macroeconomic and environmental indicators are supported by a coherent theoretical body, which is reflected in their well-organised structure and leads to their sound practice. Last but not least, the study suggests that the way the aforementioned two fields utilise indicators can provide useful guidance to the formation of future objectives in the quality-of-life, welfare and sustainability indicators’ research. Specifically, their corresponding fields should moderate their interest on composite indicators and, instead, their future research should be focused, so much on the identification of their field's key indicators that play a crucial role to the interpretation of the complex phenomena studied, as on the identification of the relationships that link these key indicators together.  相似文献   

4.
水电工程的规模和特点决定了它对环境的影响特别重大,这种影响有正效益和负效益两个方面。水电开发的环境影响评价理论和方法在世界范围内都是一个在不断探索、发展和完善的科学问题。本文以怒江中下游水电开发规划为例,通过怒江水电开发规划环境影响因子的筛选和环境影响的定量分析,对开发方案的长期和整体的环境影响效益和成本进行估算,即估算项目实施后年环境成本和效益流量。评价结果表明,怒江中下游4级水电开发的直接环境效益为2.77×108元/a,环境成本总值约为3.96×108。评价结果中,直接环境效益和环境成本的比值为1∶1.4,环境影响的净现值为-1.19×108元/a;限于目前环境损益分析技术和方法还不太成熟,部分指标如怒江水电开发对文化多样性、陆生生物、水生生物等的影响,还无法找到有充分说服力的评价方法,从而使评价结果的完整性和准确性受到一定的影响。作为辅助决策依据,决策者应根据多方面的因素,综合考虑,以做出充分合理的判断和决策。  相似文献   

5.
陈晓舒  赵同谦  李聪  郑华 《生态学报》2017,37(13):4495-4504
水电开发将在局地、区域以及全球尺度上产生一系列的影响,明确这些尺度上利益相关者的成本效益、合理分配水电开发利益是减少水电开发不利影响、促进水电资源可持续利用的关键。以澜沧江干流水电能源基地建设为背景,从开发企业、移民农户、澜沧江流域政府及全球利益相关者4个利益相关者角度,选取经济、生态环境和移民生计指标对水电开发的利益再分配进行评估,结果显示:尽管水电开发总体效益大于成本,比例为4.27∶1,且水电开发所涉及的开发企业、政府流域及全球利益相关者所获得的利益大于成本,成本效益比例分别为1∶3.93、1∶3.10、1∶13.11;但移民农户成本却大于效益,比例为1.48∶1。水电开发企业等利益主体应增加生态补偿强度,才能确保移民农户的净收益不降低。该研究表明:不同利益相关者分析有助于了解成本效益分配,清晰展示利益流向,减少开发项目中的不利影响,结果可为协调水电能源开发利用与流域可持续发展提供科学依据。  相似文献   

6.
深圳福田红树林鸟类自然保护区管理策略初探   总被引:12,自引:0,他引:12  
位于深圳经济特区的福田红树林鸟类自然保护区,是城市边缘一块不可多得的生物多样性宝地。面对经济建设的快速发展和市区的不断扩张,福田自然保护区正承受着来自各方面的巨大压力。如何在积极推动保护区立法的同时,通过开放式生物多样性保护管理,主动参与地方经济建设,实现与周边社区、地方政府和各相关社会利益集团结成合作伙伴关系,是本文探讨的重点。  相似文献   

7.
ABSTRACT

This was a retrospective observational analysis of all (n = 876) ST-segment elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (PPCI) at University Hospital Limerick (UHL) from 2012 to 2016 to determine whether chronological patterns existed in incidence and mortality at our center. Data were obtained from the electronic Cardiology STEMI database in UHL. Statistical analysis was performed using the Independent Samples t Test, ANOVA and Pearson’s Chi-Squared test. The rate of STEMI from 0800 and 2259 hours (46.9/hr) was greater than 2300 to 0759 hours (19.1/hr) (p < 0.001). No association was found between 30-day mortality and weekend/weekdays presentation (p = 0.81) or off/in hour presentation (p = 0.86). No seasonal variation was found in STEMI incidence at our center using international (p = 0.29) or Celtic (p = 0.82) seasonal calendars. 30-Day mortality is equivalent whether STEMI patients treated with PPCI present during “normal working hours” or during the “out of hours”/weekend period at our center. The majority of STEMIs occur during the hours 0800 to 2259, but no further chronological relationship was observed in incidence.  相似文献   

8.
Sleep and health are closely interrelated and sleep quality is a well-known contributor to perceived health. However, effects of sleep-timing preference i.e. morningness–eveningness on health has yet to be revealed. In this study, we explored the relationship between morningness–eveningness and perceived health in a sample of female working professionals (N?=?202). Sleep-timing preference was measured using the Composite Scale of Morningness. Perceived health was characterized by Center for Epidemiologic Studies Depression Scale, WHO Well-Being Scale-5 and Patient Health Questionnaire-15 scores. We also investigated possible mechanisms, including stress and health-impairing behaviours. In accordance with previous data, we found more depressive mood, lower well-being and poorer perceived health among evening types. To assess health-impairing behaviours we collected data on smoking habits, alcohol consumption, physical activity and diet. Among the possible mechanism variables, greater stress, less frequent physical activity and less healthy diet were associated with eveningness. Furthermore, stress diminished the strength of the association between morningness–eveningness and depressed mood. Physical activity attenuated the strength of the association between morningness–eveningness and well-being. No effects of alcohol consumption could be identified. Our data show that evening preference behaves as a health risk in terms of associating with poor perceived health. Our findings also suggest that this effect might be mediated by health behaviours and stress.  相似文献   

9.
费威  刘心  杨晨 《生态学报》2015,35(11):3797-3807
对经济与环境效率的科学评价是实现区域可持续发展的前提。运用物质流分析将辽宁省经济系统中数据进行物质化处理,再利用改进的数据包络分析模型对环境和经济效率进行综合评价。结果表明:辽宁省物资消费不主要依赖于进口,向其它地区物质输出量大;环境效率评价的综合效率主要受规模因素影响而显著低于纯技术效率,而整体经济的综合效率却主要受纯技术效率影响而下降。第二产业比重依然偏大的产业结构特征是导致上述结果的主因。进一步改造提升传统产业,发展战略性新兴产业,提高第三产业发展水平,扩大环保规模,促进居民生活质量水平全面提升,将是辽宁省以及与之相似的资源依赖型区域可持续发展的方向。  相似文献   

10.
11.
The lateral geniculate nuclear complex of albino rats was investigated with respect to the development of neurotransmitters/neuromodulators such as glutamate, cholecystokinin and vasoactive intestinal polypeptide at gestational day 18, various postnatal age periods and in the adult using immunohistochemical methods. The study shows the unequivocal presence of and the sequential changes in the profile of glutamate while cholecystokinin and vasoactive intestinal polypeptide are not demonstrable at any of the age periods. Glutamate is seen both in the cells and fibres from 40 postnatal day onwards and immunoreactivity is more intense in the adult. The findings are discussed with relevance to the role of neurotransmitters in development.  相似文献   

12.
循环农业是当前农业可持续发展理念的具体运作模式。对能值分析方法优化,使其更适合循环复合生态系统的应用上进行优化,并以福建省福清星源循环农业产业示范基地为例验证,评价复合生态系统的可持续发展程度和经济效益。结果表明改进的能值分析方法对循环复合农业生态系统的可持续发展评价更科学,复合系统的可持续发展指数比单纯的生猪养殖提高23.44%—33.86%,在4种组合的循环模式中以"生猪养殖-沼气工程-有机肥生产-种植业"循环复合生态系统整体效益最佳,其可持续发展指数最高,环境负载率最低,净能值产出率仅略低于"生猪养殖-沼气工程-种植业"复合系统。  相似文献   

13.
农业生产专业化、集约化背景下,种养分离越发严重,畜禽粪便排放与环境之间矛盾日益突出,农业可持续发展面临重大挑战.本研究以山东省为例,基于1999-2015年种养系统投入产出资料,利用能值的方法,定量分析了山东省域及市域种养系统可持续发展指数的空间格局及其演变趋势.结果表明:1999-2015年,山东省种养系统的可持续性减弱.可持续发展指数呈极显著下降趋势,2015年较1999年下降了22.0%;净能值产出率和环境负载率均呈极显著增加趋势,单位经济投入获得的利益显著增加,同时种养生产对环境的压力明显加大,这主要与电力、复合肥、农业机械等工业资源投入量的增加密切相关.山东省各地市种养系统可持续发展水平具有差异.大部分地市种养系统的可持续发展指数较高,而沿海地区(威海、烟台)和工业城市(淄博)则较低.同时,各地市种养系统的可持续发展态势也具有差异.鲁中和鲁南地区可持续性逐年减弱,鲁北地区可持续性逐年增强.以2015年为本底数据进行情景分析,发现种养高度结合(100%粪便有机肥替代化肥)情景的可持续发展指数可达8.4,是种养结合现状(30%粪便有机肥替代化肥)的2.6倍.  相似文献   

14.
Examinations of 23 forms ofCallicebus were made to elucidate their phylogenetic relationships based on cranial measurements. Multivariate statistical methods of distance analysis utilizing Q-mode correlation coefficients and principal component analysis were employed. As a result, the following five distinct groups were recognized morphometrically among the 23 species and subspecies: theDonacophilus, Cupreus, Moloch, Personatus, andTorquatus groups. Moreover, the phenetic characters of cranial size, karyotype, pelage coloration, and geographic range were consistent with the results of this group classification. It could be safely concluded therefore that these groups represented phylogenetically independent groups, in view of the fact that the rate of character differentiation was not appreciably different among closely related groups. Of the five groups, thePersonatus andTorquatus groups were respectively considered to maintain a higher peculiarity of character differentiation within theCallicebus phylogeny, since these two groups individually displayed the higher magnitudes of differentiation in both their craniometric shape and some phenetic features. Conversely, the other three groups were considered to be closer to each other in theCallicebus phylogeny.  相似文献   

15.
以石羊河流域为研究区,基于干旱内陆河流域生态特征和遥感数据快速、客观、大面积观测的特点,采用遥感模型计算湿度、绿度、干度和热度等指标,并构建石羊河流域生态脆弱性评价指标体系,在此基础上运用空间主成分分析法(SPCA)对石羊河流域2000和2016年生态脆弱性时空演变及动因进行了分析。研究结果表明:(1)从各遥感指数空间分布来看,湿度和绿度指标均值在17年间呈增长趋势,证明该流域水源涵养能力变好,植被覆盖率变大;干度指标均值有所下降,表明该流域地表裸露程度有所降低;而与植被和水资源关系密切的地表温度均值呈逐年上升趋势,说明该流域水热平衡差异进一步增加,对未来生态脆弱性影响显著;(2)从全流域生态脆弱性时空演变特征来看,该流域主要以强度和中度脆弱为主,17年间生态脆弱性整体上呈缓慢降低趋势;(3)从不同的海拔生态脆弱性分布来看,中山区(1000—2000m)最高,高中山区(2000—3000m)次之,高山区(3000m)最低,17年间中山区生态脆弱性有所下降,而高中山区与高山区却呈上升的趋势;(4)从不同的行政区划生态脆弱性来看,金川区、凉州区、永昌县、民勤县和古浪县整体上处于中度和强度脆弱水平,而天祝县和肃南县处于轻度和微度脆弱水平;(5)从生态脆弱性的演变动因来看,4个指标对石羊河流域生态脆弱性影响均为显著。2000年生态脆弱性的主导影响因子依次为热度湿度绿度干度,而2016年为热度干度绿度湿度。总的来看,石羊河流域生态脆弱程度近年来有所降低,但综合治理工作仍任重道远。本文的遥感方法和分析思路对该流域生态脆弱性保护及治理提供一定的理论基础和决策依据。  相似文献   

16.
Ongoing success throughout regional development is contingent on maintaining the function, quality and harmony progress in society, economy and environment domains, so exploring the interaction and relation among them should be considerable significant. The model by coupling principal component analysis and vector autoregressive, which relate the aggregated values and dynamic analysis among factors, is proposed to achieve the qualitative and quantitative analysis of interaction and relation among society, economy and environment subsystem, providing a framework to conceptualize the influences among their changes and simulate the future scenarios in the Bohai Rim region. The impulse response analysis and variance decomposition of vector autoregressive method, in particular, permit dynamic interaction between every two systems and display clear decomposition of contribution for each change, respectively. This study results show that: there is a virtuous circle of promotion between economic growth and social progress no matter which is regarded as the endogenous variable during the study period, and yet the negative effect to environmental changes had been produced; what the improvement of social and environmental situation need most might be advancing its own progress; it is also reflected that the entire complicated system walk on the path of unsustainable development due to the evident disequilibrium of three subsystems; and the scenario analysis results obviously tell that in order to attain coordinated development, the annual growth rate of 12% to 16% of overall environmental level should be anticipated along with 8% of social and economic level improve. The study guide future possibilities for relatively more harmonious interconnections among social, economic and the environmental development.  相似文献   

17.
马奔  严冬  温亚利 《生态学报》2023,43(10):4202-4211
国家公园内人与野生动物冲突严重,建立野生动物肇事保险机制是减缓冲突的重要举措。以大熊猫国家公园周边社区为例,分析建立国家公园以及农户风险偏好对野生动物肇事保险购买意愿的影响,并探讨冲突程度和制度信任的中介效应。研究结果表明建立国家公园显著增加了农户野生动物肇事保险购买意愿,而农户风险偏好对保险购买意愿会产生负向显著影响。冲突程度和制度信任是重要的中介变量,冲突程度和制度信任均对农户保险购买意愿产生正向显著影响。建立国家公园显著增加了人与野生动物冲突严重程度,进而对保险购买意愿产生正向影响。此外,建立国家公园显著降低了农户制度信任,进而对保险购买意愿产生负向影响。农户风险偏好对野生动物肇事损失程度产生正向显著影响,进而对保险购买意愿产生正向影响。农户风险偏好对制度信任影响并不显著。基于此,研究提出吸纳社会资本参与,拓宽野生动物肇事保险资金来源,开展社区共管、地役权补偿等措施提升社区信任以及建立基于农户自主防护行为的野生动物肇事保险机制等政策建议。  相似文献   

18.
Chronotypes are classified as morning, evening, or intermediate, but there are reports of a bimodal type. This study was undertaken to describe the characteristics of the bimodal chronotype and to explore relationships between the bimodal type and psychiatric disorders, fatigue, and quality of life. A total of 2389 subjects from a Korean national epidemiological survey of psychiatric disorders responded during face-to-face interviews. The Korean Composite International Diagnostic Interview was used to diagnose psychiatric disorders, and the Composite Scale of Morningness was used to assess chronotypes. Among intermediate-type subjects, those with a positive bimodal index were classified as bimodal type. In the present study, the proportions of bimodal, morning, intermediate, and evening types were 4.8%, 10.8%, 73.3%, and 11.1%, respectively. Distributions of sociodemographic variables were similar for the bimodal and intermediate types. After controlling for sociodemographic variables, any mood disorder and major depressive disorder were found to be significantly more associated with the bimodal type than the morning type, and dysthymic disorder was significantly more associated with the bimodal type than the intermediate type. For quality-of-life domains, moderate or extreme pain/discomfort was complained about more by subjects with the bimodal type than other types. In summary, the study shows chronotypes differ with respect to their relationships with mood disorder and quality of life. Before the bimodal type is classified as a clinically valid type, further investigations are needed to examine its psychological, physiological, and genetic characteristics.  相似文献   

19.
Carbon use efficiency (CUE, the ratio between the amount of carbon incorporated into dry matter to the amount of carbon fixed in gross photosynthesis) is an important parameter in estimating growth rate from photosynthesis data or models. It previously has been found to be relatively constant among species and under different environmental conditions. Here it is shown that CUE can be expressed as a function of the relative growth rate (rGR) and the growth (gr) and maintenance respiration coefficients (mr): 1/CUE = 1 + gr + mr/rGR. Net daily carbon gain (Cdg), rGR, and CUE were estimated from whole‐plant gas exchange measurements on lettuce (Lactuca sativa L.) ranging from 24 to 66 d old. Carbon use efficiency decreased from 0.6 to 0.2 with increasing dry mass, but there was no correlation between CUE and Cdg. The decrease in CUE with increasing dry mass was correlated with a simultaneous decrease in rGR. From the above equation, gr and mr were estimated to be 0.48 mol mol?1 and 0.039 g glucose g–1 dry matter d?1, respectively. Based on the gr estimate, the theoretical upper limit for CUE of these plants was 0.68. The importance of maintenance respiration in the carbon balance of the plants increased with increasing plant size. Maintenance accounted for 25% of total respiration in small plants and 90% in large plants.  相似文献   

20.
The neurocognitive and behavioral profile of individuals with 47,XYY is increasingly documented; however, very little is known about the effect of a supernumerary Y‐chromosome on brain development. Establishing the neural phenotype associated with 47,XYY may prove valuable in clarifying the role of Y‐chromosome gene dosage effects, a potential factor in several neuropsychiatric disorders that show a prevalence bias toward males, including autism spectrum disorders. Here, we investigated brain structure in 10 young boys with 47,XYY and 10 age‐matched healthy controls by combining voxel‐based morphometry (VBM) and surface‐based morphometry (SBM). The VBM results show the existence of altered gray matter volume (GMV) in the insular and parietal regions of 47,XYY relative to controls, changes that were paralleled by extensive modifications in white matter (WM) bilaterally in the frontal and superior parietal lobes. The SBM analyses corroborated these findings and revealed the presence of abnormal surface area and cortical thinning in regions with abnormal GMV and WMV. Overall, these preliminary results demonstrate a significant impact of a supernumerary Y‐chromosome on brain development, provide a neural basis for the motor, speech and behavior regulation difficulties associated with 47,XYY and may relate to sexual dimorphism in these areas .  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号