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1.
黄土高原植被景观多尺度变化及其与地形的响应关系   总被引:2,自引:0,他引:2  
基于RS和GIS技术,利用黄土高原近30年不同分辨率的归一化植被指数(NDVI),采用基于小波分析的多尺度空间统计学方法,研究不同时期黄土高原植被景观的多尺度变化特征及其与地形的响应关系。结果表明:(1)黄土高原植被景观1982—2011年期间发生了周期性变化。其中,1990年以前为植被恢复阶段,1990—2001年为植被退化阶段,2001年以后为植被恢复阶段。(2)植被景观的空间异质性与数据获取的时间、数据分辨率、空间位置和地形均有关。一方面,植被指数和数据分辨率越高,植被景观的空间异质性就越大,而且沿经度方向植被景观的空间差异性大于纬度方向;另一方面,NDVI的多尺度变化特征与地形因子有不同程度的相关性,表现为:高程地形湿度坡度坡向,这对于今后黄土高原植被景观的合理布局,提高生物多样性,控制水土流失,增强景观的连续性具有特别重要的意义,也可为指导生态环境建设提供基础资料。  相似文献   

2.
不同尺度上植物叶气孔导度对升高CO2的响应   总被引:8,自引:2,他引:6  
植物叶气孔导度对大气CO2浓度升高的响应可表现在以下几个层面:在叶水平上,叶气孔导度和气孔密度下降;在植物个体水平上,单位叶面积蒸腾下降,植株的水分利用率升高;在生态系统水平上,蒸散降低,土壤泾流和土壤水分含量增加;在全球尺度上,扩大了温室气体的增温效应,同时也降低了全球降雨量增加的趋势。正是因为植物叶气孔导度的变化会影响全球水循环,所以它在全球变化中起着非常重要的作用。但目前的研究结果还不能外推到更大的尺度上去。  相似文献   

3.
富硒植物与人体健康   总被引:5,自引:0,他引:5  
硒是生态环境中的一个重要微量元素。1957年施瓦茨发现,硒有抗氧化作用,并首次提出硒是人体的必需元素。同年,谷跳甘肽过氧化物酶被发现。1971年,Rotz-uch证明,硒是该酶的组成成分。1973年,世界卫生组织宣布硒是人体生命的必需元素。近年,德国植物营养学家已将硒列于植物有益元素的行列。硒通过生物地球化学营养链:岩石一土壤和水一植物一动物和人给人和动物以影响。几十年来的研究结果表明,人和动物的四十多种疾病与体内硒缺乏有关,典型疾病如地方性克山病、大骨节病、牲畜的白肌病。禽类的渗出性素质等,而硒制剂对这些疾病均…  相似文献   

4.
光学透明技术是一种通过各种化学试剂,将原本不透明的生物样本实现透明化,并在光学显微镜下深度成像的技术。结合多种光学显微成像新技术,光学透明技术可对整个组织进行成像和三维重建,深度剖析生物体内部空间特征与形成机制。近年来,多种植物光学透明技术和多尺度成像技术被陆续研发,并取得了丰硕的研究成果。该文综述了生物体光学透明技术的基本原理和一些新技术,重点介绍基于光学透明技术开发的新型成像方法及其在植物成像与细胞生物学中的应用,为后续植物整体、组织或器官的透明、成像与三维重构及功能研究提供理论依据和技术支持。  相似文献   

5.
植物气孔导度的环境响应模拟及其尺度扩展   总被引:5,自引:0,他引:5       下载免费PDF全文
气孔导度是衡量植物和大气间水分、能量及CO2平衡和循环的重要指标,探讨气孔导度与环境因子的关系及其模拟,以及气孔导度在叶片、冠层及区域尺度间的尺度转换及累积效应,对更好地认识植被与大气间的水热运移过程,合理评价植被在陆面过程中的地位和作用都具有重要意义。从植物气孔导度与环境因子的关系、气孔导度模拟以及尺度扩展三个方面,对前人的研究成果进行了概括总结。从叶片和冠层两个尺度出发,归纳总结了前人对于不同植物气孔导度与环境因子关系的研究成果,发现由于不同植物的遗传特性、测定时的环境、时间尺度的不同,以及未考虑各个环境因子的相互作用对气孔导度的影响,由此得到的气孔导度与环境因子之间的关系也不尽一致。对各单一环境因子与气孔导度的关系,给出了生理学解释,从根本上说明了环境因子变化对气孔导度的影响,而研究环境因子对气孔导度的综合影响时,应对各环境因子进行系统控制与同步观测。模拟计算植物气孔导度的模型主要有Jarvis模型和BWB模型两类,这些模型的模拟能力随着研究对象、试验区域、环境条件的改变而存在一定的差异,在具体使用时应结合实际情况选择最优模型进行模拟。除上述常用模型外,还总结了其他学者分别从不同角度提出的新的模型,对现有气孔导度模型进行了全面的总结。从叶片-冠层、冠层-区域两个方面归纳总结了前人关于气孔导度尺度扩展的研究成果,发现叶片-冠层的尺度扩展研究较成熟而冠层-区域的尺度扩展在模拟精度的验证方面存在困难。针对以下几个方面提出了今后气孔导度的研究重点:(1)结合研究对象所在的区域及环境条件,选择最优模型进行模拟;(2)综合考虑环境因子之间的相互作用及其对气孔导度的累积影响;(3)BWB模型与光合模型的耦合;(4)提高大尺度范围内的气孔导度模拟精度。  相似文献   

6.
邓丽明  杨骥  尹小玲  贾凯  孙嘉  舒思京  黄爱琳 《生态学报》2024,44(20):9094-9107
城市化与生态系统服务供需相互作用关系在不同空间尺度下具有显著差异性。基于供需空间不匹配视角揭示生态系统服务对城市化的多尺度响应规律是实现城市可持续性发展的重要前提条件。研究从1 km×1 km、2.5 km×2.5 km、5 km×5 km、10 km×10 km、区县域和市域等6个空间尺度分析了2020年粤港澳大湾区生境质量服务、固碳服务和土壤保持服务供需关系和空间分异规律,并探究不同空间尺度生态系统服务供需关系对城市化的响应。结果表明:(1)生态系统供需错配集中分布在中心城区,空间尺度的增加加剧了中心城区的赤字程度。(2)城市化指数与生态系统服务供需比率在多空间尺度上均呈负相关关系。随着空间尺度增加,高城市化-生态系统服务赤字型逐渐向中心城区延伸,低城市化-生态系统服务盈余型向非城市化地区聚集。(3)在10 km和区县尺度上,生态系统服务供需对城市化响应最为剧烈,是解决二者不平衡发展的最佳尺度。本研究为高度城市化地区相关管理部门提供优化生态系统服务供需平衡的保护管理政策制定提供科学依据。  相似文献   

7.
陈俊辰  贺淑钰  薛晶  张环宇  李兆华  王玲  李昆 《生态学报》2023,43(12):4835-4846
多种生态系统服务相互关系及其对景观配置响应的多尺度分析一直是生态系统服务研究的热点问题,对于厘清生态系统服务尺度效应和实现区域分级管理具有重要的意义。以湖北省为研究区域,采用遥感、土地利用类型、水文、气象、土壤等多元数据,从5 km×5 km、10 km×10 km、15 km×15 km、20 km×20 km、25 km×25 km、县域和市域等7个递增尺度分析4种生态系统服务(水源供给、碳固持、粮食生产、水质净化)对景观配置的响应关系。结果表明:(1)4种生态系统服务的空间分布具有较强的异质性,粮食生产服务的高值区与水质净化服务的低值区主要分布于湖北省中部和东部的耕地集中区域,碳固持与水源供给呈现相反的空间特征。(2)生态系统服务权衡关系的作用强度随尺度增加而减弱,而协同关系呈增加趋势;同时服务间相互作用强度的变化大于作用方向的变化。(3)景观配置对生态系统服务的影响程度在县域和市域尺度上大于格网尺度。结果反映了受尺度变化中“削峰填谷”过程的影响,景观配置对生态系统服务影响的大小和正负效应具有尺度差异性。研究结果可为区域生态系统服务分级管理和景观格局调控提供科学参考。  相似文献   

8.
基于多光谱影像的森林树种识别及其空间尺度响应   总被引:1,自引:0,他引:1  
当前,不同空间分辨率卫星影像对森林类型识别结果中普遍存在的尺度效应,而且纹理参量对不同尺度下树种识别精度的影响仍缺乏广泛认知.本研究以中国东北旺业甸林场为研究区,采用观测时相同步、地理坐标匹配的GF-1 PMS、GF-2 PMS、GF-1 WFV,以及Landsat-8 OLI卫星传感器数据组成空间尺度观测序列(1、2、4、8、16、30 m),并结合支持向量机(SVM)模型,探讨了区域内5种优势树种遥感识别结果的尺度变化规律及其纹理特征参数的影响,同时检验了基于尺度上推转换影像的树种识别结果差异.结果表明: 影像空间分辨率对区域树种识别结果具有显著影响,其中,研究区森林树种识别的最佳影像分辨率为4 m,当分辨率降低至30 m时,树种识别结果最差.在1~8 m影像分辨率范围内,增加纹理信息能够显著提高不同优势树种的识别精度,使总分类精度提升了2.0%~3.6%,但纹理信息对16~30 m影像的识别结果没有显著影响.与真实尺度卫星影像相比,基于升尺度转换影像的树种识别结果及其尺度响应特征存在显著差异,表明在面向多个空间尺度的遥感观测和应用研究中,需要采用真实分辨率影像以确保结果的准确性.  相似文献   

9.
在3S技术平台支撑下,用典范对应分析排序方法对武夷山风景区景观格局与环境因子的关系及其尺度效应进行了分析。结果表明,在6个取样尺度上(粒度分别为30 m、90 m、150 m、210 m、300 m和450 m),排序轴总特征值呈递减趋势,依次为9.626、7.814、5.708、4.019、3.386、2.310;前4轴累积景观环境解释量变化程度小(97.3%~98.8%),前2轴各尺度平均累积解释量为89.4%,景观-环境的相关系数呈先减后增趋势。6个尺度中环境因子与景观格局的平均相关系数依次为郁闭度(0.7989**)>腐殖质层厚度(0.7248**)>海拔(0.6083**)>坡度(0.6132**)>经度(-0.4064**)>土层厚度(0.3696**)>纬度(0.0614)>坡向(0.0295)。风景区景观类型可划分为3类,即与海拔因子密切相关的裸地、河流、建设用地、农田景观,与土壤因子密切相关的杉木林、马尾松林、阔叶林景观,以及受人类活动密切相关的茶园、经济林、竹林、灌草丛景观。因此,风景区景观格局与环境因子间的关系具有尺度效应,各环境因子对排序轴相关系数的影响规律在6个取样尺度内可尺度推绎。  相似文献   

10.
景观格局对植物多样性的影响已经在很多研究中得到了验证,但有关城市景观的影响仍然知之甚少.为了探究城市化景观格局对植物多样性的影响及其尺度效应,本研究在北京市顺义区调查了105个样地,计算每个样地的c和p多样性指数;并以100 m为步长,分析了100~1000 m范围内的10个尺度43个城市的景观格局指数.结果表明:在所...  相似文献   

11.
  总被引:2,自引:0,他引:2  
The morphological structure and optical properties of the wings of 14 species of Morphidae have been investigated. Most of the scales of the iridescent species of Morphidae (Lepidoptera) present a very particular structure. The ground scales, responsible for the major part of the optical properties, are covered by a very regular set of longitudinal ridges. The ridges themselves are constituted by a superposition of lamellae that act locally as a multilayered structure. This very specific morphology leads to both interferences and diffraction effects. The first one is responsible of the brilliant blue coloration of the males, while the second one diffracts this colored light at a very large angle. These two phenomena give to the butterfly a very effective long-range communication system. The morphological characteristics of the scales of the various species are presented in detail. Two types of optical measurement were performed on the iridescent wings of 14 different species of Morphidae: spectroscopic measurements under various incidences and gonioscopic measurements for a given incidence angle and wavelength. The first allows a determination of the index of refraction of the cuticular material. The second leads to the drawing of spatial diffraction maps. It shows that most of the reflected light is diffracted laterally over a very large angle (90° 〈 0 〈 120°, according to the different species) and that this repartition depends of the polarization of incident light. As predicted by previous calculations, the dissymmetric structure of the ridge is responsible for the separation of the polarization modes in the various diffraction orders.  相似文献   

12.
Objectives This audit aims to evaluate the effectiveness of delivering an equivalent primary care service to a long-term forensic psychiatric inpatient population, using the UK primary care national Quality and Outcomes Framework (QOF).Method The audit compares the targets met by the general practitioner with special interest (GPwSI) service, using local and national QOF benchmarks (2005-2006), and determines the prevalence of chronic disease in a long-term inpatient forensic psychiatry population.Results The audit results show that the UK national QOF is a useful tool for assessment and evaluation of physical healthcare needs in a non-community based population. It shows an increased prevalence of all QOF-assessed long-term physical conditions when compared to the local East London population and national UK population, confirming previously reported elevated levels of physical healthcare need in psychiatric populations.Conclusions This audit shows that the UK General Practice QOF can be used as a standardised instrument for commissioning and monitoring the delivery of physical health services to in-patient psychiatric populations, and for the evaluation of the effectiveness of clinical interventions in long-term physical conditions. The audit also demonstrates the effectiveness of using a GPwSI in healthcare delivery in non-community based settings. We suggest that the findings may be generalisable to other long-term inpatient psychiatric and prison populations in order to further the objective of delivering an equivalent primary care service to all populations.The QOF is a set of national primary care audit standards and is freely available on the British Medical Association website or the UK Department of Health website. We suggest that primary care workers in health economies who have not yet developed their own national primary care standards can access and adapt these standards in order to improve the clinical standards of care given to the primary care populations that they serve.  相似文献   

13.
    
Objective: To examine the prevalence and association of health‐related quality of life (HRQOL) with trying to lose weight and with weight loss practices (eating fewer calories, physical activity, and both) among overweight and obese U.S. adults ≥ 20 years of age. Research Methods and Procedures: This study used data from the 2001 to 2002 National Health and Nutrition Examination Survey, a continuous annual survey of the civilian non‐institutionalized U.S. population. This analysis included those ≥ 20 years of age with BMI ≥ 25 (n = 2578) who responded to four standard HRQOL measures that assessed general health status and recent physical health, mental health, and activity limitation. Results: Among obese men, but not women, there were significant increasing linear trends in the adjusted prevalence of trying to lose weight as physically unhealthy and activity limitation days increased. Regardless of BMI or HRQOL, reducing calories was a common weight loss practice (66% to 86%). Except for recent activity limitation, respondents with BMI ≥ 35 did not generally differ by HRQOL level in the attainment of recommended physical activity either alone or in combination with reduced calories, whereas those in the BMI 25 to 34.9 groups often differed significantly by HRQOL level. Specifically, increased unhealthy or activity limitation days were associated with reduced prevalence of attained physical activity. Discussion: Our findings indicate an association between trying to lose weight and a greater number of unhealthy days reported by obese men, suggesting that these men may be influenced by traditional clinical weight‐loss counseling that is prompted by weight and comorbidity, whereas women had a high prevalence of trying to lose weight irrespective of weight and HRQOL. Assessment of HRQOL, especially measures that evaluate physical domains, could provide subjective information to assist with weight counseling.  相似文献   

14.
目的:观察8周广场舞锻炼对中老年女性身心健康的影响。方法:60名中老年女性(年龄55~70岁)随机分为2组(n=30),即对照组和运动组。运动组进行中等强度的广场舞运动60 min,隔日1次,每周运动3次;对照组不组织运动,原有日常生活节律保持不变,持续8周。试验前后测试体重、腰围、臀围、体重指数、腰臀比、血压、安静心率、肺活量、台阶指数、握力、闭眼单脚站立、血清总胆固醇(TC)、血清甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、血糖(Glu)、SCL-90症状自评量表等指标。结果:经过8周广场舞锻炼,运动组成员的体重、体重指数、腰臀比、血压和安静心率均有明显下降(P<0.05,P<0.01),同时血清TC、TG、LDL-C、Glu含量显著下降(P<0.05),而运动组成员的肺活量、握力和闭眼单脚站立时间及血清HDL-C水平显著升高(P<0.01),运动组心理健康水平发生一定的变化,强迫症和人际关系有显著改善(P< 0.05)。结论:广场舞锻炼对中老年女性身心健康可产生明显的改善作用,是一项适合中老年女性的健身锻炼方式。  相似文献   

15.
People with severe mental illness (SMI) experience some of the worst physical health and die younger than almost any section of the population. Mental health professionals have seemed strangely indifferent to this inequality, which in other areas of health would be a national scandal. In this editorial we discuss the recently introduced smoking ban in inpatient mental health service settings, which will offer mental health services an opportunity to implement creative, evidence-based strategies to help people with SMI address smoking and nicotine addiction. In doing this, we refer to National Institute for Health and Clinical Excellence (NICE) guidance. This guidance forms the basis of national smoking policies for the general population and forms a starting point for those with SMI. Such a strategy will necessarily involve close collaboration with primary care, and we specifically examine how this might be achieved.  相似文献   

16.
    

Objectives

The aim of this study was to test the hypothesis that ethnic and ethnolinguistic discrimination, and Post-Traumatic Stress Disorder (PTSD) related to being Indigenous as well as different aspects of acculturative stress, are associated with poorer health and higher levels of depression among the Nahua Indigenous communities.

Materials and methods

Our quantitative survey was carried out in four different regions inhabited by the Nahua people in Mexico. Self-rated health and depression, the symptoms of PTSD, two facets of acculturative stress and ethnolinguistic discrimination were assessed by questionnaires. The data were analyzed using binary logistic regression models.

Results

The symptoms of PTSD and acculturative stress experienced in the workplace were significantly associated with a higher risk of poor self-rated health, adjusted for various socio-demographic characteristics. Acculturative stress, discouragement of language use, language avoidance and ethnolinguistic discrimination were related to a higher risk of depression and PTSD.

Discussion

Our research implies that ethnic and linguistic discrimination, acculturative stress and the memory of harm linked to being Indigenous reflected in the symptoms of PTSD, are important predictors of poorer health and depression among Nahua groups in Mexico. These adverse effects could be significantly counteracted by effective dealing with stigmatization and discrimination against Indigenous people in Mexico and by replacing strong assimilation pressures with integrational approaches that respect ethnolinguistic diversity and reduce socioeconomic marginalization.  相似文献   

17.
城市景观影响人居环境健康的研究进展   总被引:1,自引:0,他引:1  
城市景观类型和格局能够改变居民的生理和心理活动,对人居环境健康有着重要影响,当前尚缺少对影响方式和程度的系统研究.通过综述绿色空间与人居环境健康的国内外文献,从生理健康和心理健康角度归纳了绿色空间对城市人居环境健康的影响.当前研究存在的问题包括侧重于单个学科领域研究、局限于传统数据、侧重于静态分析、研究区域相对局限、研...  相似文献   

18.
This paper examines a controversy that arose while developing a supplement to Mental Health: A Report of the Surgeon General that was focused on ethnic minority mental health. The controversy involved whether and how to make recommendations about ethnic minorities seeking mental health care. We found that few studies provided information on outcomes of mental health care for ethnic minorities. In this paper, we discuss outcomes of mental health care for ethnic minorities and how to proceed in developing an evidence base for understanding mental health care and minorities. We conclude that entering representative (based on population) numbers of ethnic minorities in efficacy trials is unlikely to produce useful information on outcomes of care because the numbers will be too small to produce reliable findings. We also conclude that while conducting randomized efficacy trials for all mental health interventions for each ethnic group would be impractical, innovative and theoretically informed studies that focus on specific cultural groups are needed to advance the knowledge base. We call for theory-driven research focused on mental health disparities that has the potential for understanding disparities and improving outcomes for ethnic minority populations.  相似文献   

19.
    
Objective: To examine relationships of BMI with health‐related quality of life in adults 65 years and older. Research Methods and Procedures: In 1996, a health survey was mailed to all surviving participants ≥ 65 years old from the Chicago Heart Association Detection Project in Industry Study (1967 to 1973). The response rate was 60%, and the sample included 3981 male and 3099 female respondents. BMI (kilograms per meter squared) was classified into four groups: underweight (<18.5), normal weight (18.5 to 24.9), overweight (25.0 to 29.9), and obese (≥30.0). Main outcome measures were Health Status Questionnaire‐12 scores (ranging from 0 to 100) assessing eight domains: health perception, physical functioning, role limitations‐physical, bodily pain, energy/fatigue, social functioning, role limitations‐mental, and mental health. The higher the score, the better the outcome. Results: With adjustment for age, race, education, smoking, and alcohol intake, obesity was associated with lower health perception and poorer physical and social functioning (women only) but not impaired mental health. Overweight was associated with impaired physical well‐being among women only. Both underweight men and women reported impairment in physical, social, and mental well‐being. For example, multivariable‐adjusted health perception domain scores for women were 50.8 (underweight), 62.7 (normal weight), 60.5 (overweight), and 52.1 (obese), respectively. Associations weakened but remained significant with further adjustment for comorbidities. Discussion: Compared with normal‐weight people, both underweight and obese older adults reported impaired quality of life, particularly worse physical functioning and physical well‐being. These results reinforce the importance of normal body weight in older age.  相似文献   

20.
Public mental health deals with mental health promotion, prevention of mental disorders and suicide, reducing mental health inequalities, and governance and organization of mental health service provision. The full impact of mental health is largely unrecognized within the public health sphere, despite the increasing burden of disease attributable to mental and behavioral disorders. Modern public mental health policies aim at improving psychosocial health by addressing determinants of mental health in all public policy areas. Stigmatization of mental disorders is a widespread phenomenon that constitutes a barrier for help-seeking and for the development of health care services, and is thus a core issue in public mental health actions. Lately, there has been heightened interest in the promotion of positive mental health and wellbeing. Effective programmes have been developed for promoting mental health in everyday settings such as families, schools and workplaces. New evidence indicates that many mental disorders and suicides are preventable by public mental health interventions. Available evidence favours the population approach over high-risk approaches. Public mental health emphasizes the role of primary care in the provision of mental health services to the population. The convincing evidence base for population-based mental health interventions asks for actions for putting evidence into practice.  相似文献   

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