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1.
目的:研究张家口市大气颗粒物对慢性阻塞性肺疾病(COPD)的影响,并分析大气颗粒物对不同特征人群的影响。方法:从张家口市医保办公室获取张家口市2013年1月1日-2015年12月31日两家三甲医院COPD患者的住院病历资料,从中国环境监测总站网站获取大气污染物的监测数据,从张家口市气象局获取气象资料。建立广义相加模型(GAM),在控制长期趋势、星期几效应和温湿度影响后,应用条件Logitic回归方法评估PM_(2.5)、PM_(10)对COPD住院人次的影响。根据患者不同特征(性别、年龄、季节)进行分层分析,评估颗粒物污染的高危人群。结果:研究纳入两家三甲医院,共1984例住院COPD患者,其中男性患者1258例(63.4%)、女性患者726例(36.6%),≥75岁患者678例(34.2%),60~75岁患者936例(47.2%)、芨60岁患者370例(18.6%)。2013-2015年PM_(2.5)、PM_(10)年均浓度分别为[(36.54±20.34)μg/m~3、(84.37±52.54)μg/m~3],[(34.50±27.08)μg/m~3、(78.43±69.78)μg/m~3],[(32.04±21.35)μg/m~3、(75.46±50.02)μg/m~3],两者在移动平均滞后3d时,对COPD的影响最大,即PM_(2.5)每增加10μg/m~3,COPD住院人次增加1.90%(95%CI:1.002-1.033,P0.05),PM_(10)每增加10μg/m~3,COPD住院人次增加2.10%(95%CI:1.005-1.045,P0.05)。分层分析结果显示:PM_(2.5)、PM_(10)每升高10μg/m~3,女性COPD患者住院人次增加1.09%、1.14%,差异具有统计学意义(P0.05);≥75岁患者,COPD住院人次增加1.03%、0.99%,差异具有统计学意义(P0.05);而年龄芨60岁、60~75岁、男性以及季节分层分析中,PM_(2.5)、PM_(10)浓度与COPD住院人次无统计学意义(P0.05)。结论:颗粒物污染会增加COPD住院率,≥75岁的老年患者及女性患者更敏感。  相似文献   
2.
调亏灌溉对菘蓝水分利用及产量的影响   总被引:4,自引:0,他引:4  
通过探究水分调亏对河西地区膜下滴灌菘蓝(Isatis indigotica)各项生理指标、产量和水分利用的影响,为菘蓝高效节水种植提供理论指导。于2016年在河西走廊中部张掖市民乐县益民灌溉试验站进行菘蓝水分调亏研究,在保持苗期和肉质根成熟期充分灌溉的情况下,在菘蓝营养生长期和肉质根生长期分别进行轻度、中度和重度的水分亏缺处理,并测定各项光合生理指标、产量和水分利用率。结果表明,营养生长期和肉质根生长期的中度与重度水分亏缺显著降低了菘蓝叶片净光合速率、叶面积指数、株高及主根长,并且随水分亏缺程度加重降幅增大;而轻度水分亏缺与对照组的差异不显著。营养生长期和肉质根生长期轻度水分亏缺处理的菘蓝产量与水分利用效率最高,分别达到8 239.56 kg·hm~(–2)和24.11kg·hm~(–2)·mm~(–1);其它水分亏缺处理组产量和水分利用效率均有所降低,与对照组之间差异显著(P0.05),重度水分亏缺处理各项指标均最低。因此,最优的菘蓝水分调控处理为营养生长期和肉质根生长期的轻度水分调亏,能够降低菘蓝耗水量,提高水分利用效率且其产量不会降低。  相似文献   
3.
Many modern cities have strongly invested in the sustainability of their urban water management system. Nordic cities like Stockholm or Copenhagen are amongst pioneers in investments towards integrated urban water management. However, cities can never be fully self-sufficient due to their dependency on external (water) resources. In this paper, we quantify this water dependency with respect to food consumption in nine cities located in the five Nordic countries (Sweden, Denmark, Finland, Norway and Iceland), by means of the water footprint concept. Detailed urban water footprint assessments are scarce in the literature. By analysing national nutrition surveys, we find that urban food intake behaviour differs from national food intake behaviour. In large Nordic cities people eat generally less potatoes, milk products (without cheese), meat and animal fats and they drink less coffee than outside city borders. On the other hand, they generally eat more vegetables and vegetable oils and they drink more tea and alcoholic beverages. This leads consistently – for the six large Nordic cities Stockholm, Malmö, Copenhagen, Helsinki, Oslo and Reykjavik – to slightly smaller food related urban water footprints (−2 to −6%) than national average values. We also analyse the water footprint for different diets based upon Nordic Nutrition Recommendations (NNR) for these cities. We assessed three healthy diet scenarios: 1) including meat (HEALTHY-MEAT), 2) pesco-vegetarian (HEALTHY-PESCO-VEG) and 3) vegetarian (HEALTHY-VEG). This shows that Nordic urban dwellers 1) eat too many animal products (red meat, milk and milk products) and sugar and drink too much alcohol and 2) they eat not enough vegetables, fruit and products from the group pulses, nuts and oilcrops. Their overall energy and protein intake is too high. A shift to a healthy diet with recommended energy and protein intake reduces the urban WF related to food consumption substantially. A shift to HEALTHY-MEAT results in a reduction of −9 to −24%, for HEALTHY-PESCO-VEG the reduction is −29 to −37%, for HEALTHY-VEG the reduction is −36 to −44%. In other words, Nordic urban dwellers can save a lot of water by shifting to a healthy diet.  相似文献   
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砷是一种无处不在的有毒类金属,其强致癌性引起了人类的广泛关注。在自然环境中,砷的转化存在物理化学过程和生物过程,其中微生物介导的砷转化是环境砷行为的主要影响因素。微生物的耐砷特性与砷吸收、氧化还原、甲基化、区隔化和外排等过程密切相关。砷在微生物体内的转运转化主要与砷解毒有关,但某些微生物可利用氧化还原过程产生的能量以维持其生长需求。本文综述了微生物介导的砷吸收、转化、区隔化和外排机制,这对阐明砷的地球化学循环过程及指导砷污染土壤和水体修复、阻控农作物砷吸收等方面具有重要意义。  相似文献   
7.

Background and Aims

The structure of a forest stand, i.e. the distribution of tree size features, has strong effects on its functioning. The management of the structure is therefore an important tool in mitigating the impact of predicted changes in climate on forests, especially with respect to drought. Here, a new functional–structural model is presented and is used to assess the effects of management on forest functioning at a national scale.

Methods

The stand process-based model (PBM) Castanea was coupled to a stand structure module (SSM) based on empirical tree-to-tree competition rules. The calibration of the SSM was based on a thorough analysis of intersite and interannual variability of competition asymmetry. The coupled Castanea–SSM model was evaluated across France using forest inventory data, and used to compare the effect of contrasted silvicultural practices on simulated stand carbon fluxes and growth.

Key Results

The asymmetry of competition varied consistently with stand productivity at both spatial and temporal scales. The modelling of the competition rules enabled efficient prediction of changes in stand structure within the Castanea PBM. The coupled model predicted an increase in net primary productivity (NPP) with management intensity, resulting in higher growth. This positive effect of management was found to vary at a national scale across France: the highest increases in NPP were attained in forests facing moderate to high water stress; however, the absolute effect of management on simulated stand growth remained moderate to low because stand thinning involved changes in carbon allocation at the tree scale.

Conclusions

This modelling approach helps to identify the areas where management efforts should be concentrated in order to mitigate near-future drought impact on national forest productivity. Around a quarter of the French temperate oak and beech forests are currently in zones of high vulnerability, where management could thus mitigate the influence of climate change on forest yield  相似文献   
8.
The partial CaDSR6 (Capsicum annuum Drought Stress Responsive 6) cDNA was previously identified as a drought-induced gene in hot pepper root tissues. However, the cellular role of CaDSR6 with regard to drought stress tolerance was unknown. In this report, full-length CaDSR6 cDNA was isolated. The deduced CaDSR6 protein was composed of 234 amino acids and contained an approximately 30 amino acid-long Asp-rich domain in its central region. This Asp-rich domain was highly conserved in all plant DSR6 homologs identified and shared a sequence identity with the N-terminal regions of yeast p23fyp and human hTCTP, which contain Rab protein binding sites. Transgenic Arabidopsis plants overexpressing CaDSR6 (35S:CaDSR6-sGFP) were tolerant to high salinity, as identified by more vigorous root growth and higher levels of total chlorophyll than wild type plants. CaDSR6-overexpressors were also more tolerant to drought stress compared to wild type plants. The 35S:CaDSR6-sGFP leaves retained their water content and chlorophyll more efficiently than wild type leaves in response to dehydration stress. The expression of drought-induced marker genes, such as RD20, RD22, RD26, RD29A, RD29B, RAB18, KIN2, ABF3, and ABI5, was markedly increased in CaDSR6-overexpressing plants relative to wild type plants under both normal and drought conditions. These results suggest that overexpression of CaDSR6 is associated with increased levels of stress-induced genes, which, in turn, conferred a drought tolerant phenotype in transgenic Arabidopsis plants. Overall, our data suggest that CaDSR6 plays a positive role in the response to drought and salt stresses.  相似文献   
9.
了解城市内河中病原菌含量对城市生态安全具有重要意义。应用定量PCR( qPCR)方法,对宁波市城区6条重要内河水体中的病原菌含量及主要水质指标进行分析。结果表明,祖关山河、苏家河、南北河、后西河、史魏家河和直落河每升水体中含有病原菌基因的拷贝数分别为:3.34×105、1.47×105、4.68×105、1.75×106、9.65×106和1.33×106;且病原菌基因的含量与水体溶解氧负相关,与总氮、氨氮、浊度、总磷、高锰酸钾指数、叶绿素a和电导率呈正相关关系,但与水体透明度、温度和酸碱度无明显关系。定量PCR分析结果可望为评价城市内河水体质量提供重要参考。  相似文献   
10.
人类活动与气候变化对洪湖春旱的影响   总被引:1,自引:0,他引:1  
刘可群  梁益同  周金莲  刘敏 《生态学报》2014,34(5):1302-1310
近年来洪湖地区干旱事件频繁发生,对该地区农业生产与生态环境造成了极大影响。利用1960—2011年气候资料、近30年洪湖水文、土地利用资料,采用湖泊水量平衡方法、统计学等方法,研究分析了人类活动和气候变化对洪湖春季干旱的影响。结果表明:伴随全球气候变化该地区年降水和夏季降水呈增加趋势,而春季降水尤其是春季少雨年的降水量减少趋势明显,其减少速率为12.57 mn/10a,达到了α=0.1显著水平;洪湖5月水位高度依赖春季降水,降水对它贡献率为0.36 m/100mm。近20年来,洪湖周边两县市水产养殖面积增加了7倍,在降水偏少时,农业灌溉需水量20a增加了4.14×10~8m~3以上;水产养殖消耗大量春季水资源,对洪湖5月水位的影响率为-0.158 m/10~4hm~2,达到了0.1的显著性水平。人类活动与气候变化是洪湖春旱增多加重两个重要原因,比较它们的变化量与影响率,人类活动对洪湖春旱的影响更大。为维护洪湖生态功能,减轻干旱影响,必须调整农业结构。  相似文献   
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