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51.
52.
通过2013年1月1日~2017年7月31日兰州市呼吸系统疾病逐日就诊资料和气象资料,采用分布滞后非线性模型(DLNM)方法,分析0~30d滞后影响,研究极端低温对不同年龄(<15岁、16~45岁、46~60岁、>60岁)和性别人群呼吸系统疾病就诊人次的影响.结果发现:日均最低温度对相对危险度(RR)的最大RR变化范围为0.89~1.41,变化趋势整体呈现出V字型,在低温附近,温度越低,RR越高;滞后0~4d,极端低温代表的冷效应影响最为显著;滞后5~19d,在日均最低温度0℃附近,出现新的峰值,冷效应对RR的贡献有所下降,热效应对RR的贡献完全消失;滞后20~30d,日均最低温度为-10℃时,出现RR最小值,0℃温度点附近维持RR峰值;滞后22d时,滞后影响完全消失.在极端低温条件下,呼吸系统疾病对低龄人群表现出长期滞后性和高发性,对高龄人群表现出短期滞后性.男性比女性患病的滞后效应更长,患病风险更大. 相似文献
53.
Using self‐determination theory to understand the relationship between calling enactment and daily well‐being
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This paper contributes to the calling literature by using self‐determination theory—a theory that makes distinctions between different types of motivation—in order to gain a better understanding of how enacting a calling may relate both positively and negatively to well‐being. We use a daily diary method novel to the calling field and a sample with a distinctive calling, Church of England clergy. We expect daily calling enactment to relate positively to daily well‐being via more autonomous forms of motivation (intrinsic and identified motivation) and negatively via less autonomous forms (introjected motivation). Furthermore, we consider how the relationship between calling enactment and motivation may be moderated by perceived competence. The hypotheses were tested using multi‐level structural equation modeling. There was strong support for calling enactment relating positively to well‐being, and this relationship was fully mediated by intrinsic and identified motivation; the hypothesized negative pathway, from calling enactment, to introjected motivation, to well‐being, was not supported. However, perceived competence was found to moderate some of the relationships between calling and the motivation types, where calling enactment is linked to lower introjected motivation at high levels of competence. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
54.
Ronald A. Chadderton Arthur C. Miller Archie J. McDonnell 《Journal of the American Water Resources Association》1981,17(5):760-766
A study was made to analyze and modify procedures used for stream assimilation capacity and point source wasteload allocation calculations. This paper describes the sources and types of information collected and the analysis of alternative computation methods developed during the study. The calculation of stream assimilation capacity or Total Maximum Daily Load (TMDL), will depend upon assumed stream flows, quality standards, reaction rates, and modeling procedures. The “critical conditions” selected for TMDL calculations usually are low flows and warm temperatures. The complexity of water quality models used for TMDL and allocation calculations can range from simple, complete mixing to calibrated and verified mathematical models. A list of 20 wasteload allocation (WLA) methods was developed. Five of these WLA's were applied to an example stream to permit comparisons based on cost, equity, efficient use of stream assimilation capacity, and sensitivity to fundamental stream quality data. Based on insensitivity to data errors and current use by several states, the WLA method of “equal percent treatment” was preferable in the example stream. 相似文献
55.
Joel W. Herr Carl W. Chen Robert A. Goldstein Rick Herd J. Michael Brown 《Journal of the American Water Resources Association》2003,39(2):289-300
ABSTRACT: The Cheat River of West Virginia is impaired by acid mine drainage (AMD). Fifty‐five of its river segments were placed on the 303(d) list, which required calculations of total maximum daily load (TMDL) to meet the water quality criteria for pH, total iron, aluminum, manganese, and zinc. An existing watershed model was enhanced to simulate AMD as nonpoint source load. The model divided a watershed into a network of catchments and river segments. Each catchment was divided into soil layers, which could contain pyrite, calcite and other minerals. A kinetic expression was used to simulate pyrite oxidation as a function of oxygen in the soil voids. Oxygen in the soil voids was consumed by pyrite oxidation and replenished by earth breathing. The by‐products of pyrite oxidation were calculated according to its mass action equations. Chemical equilibrium was used to account for the speciation of ferrous and ferric irons and precipitation of metal hydroxides. Simulated hydrology and water quality were compared to available data. The USEPA used the calibrated model to calculate the TMDLs in the Cheat River Watershed. 相似文献
56.
Being constantly connected to others via e‐mail and other online messages is increasingly typical for many employees. In this paper, we develop and test a model that specifies how interruptions by online messages relate to negative and positive affect. We hypothesize that perceived interruptions by online messages predict state negative affect via time pressure and that perceived interruptions predict state positive affect via responsiveness to these online messages and perceived task accomplishment. A daily survey study with 174 employees (a total of 811 day‐level observations) provided support for our hypotheses at the between‐person and within‐person level. In addition, perceived interruptions showed a negative direct association with perceived task accomplishment. Our study highlights the importance of being responsive to online messages and shows that addressing only the negative effects of perceived interruptions does not suffice to understand the full impact of interruptions by online messages in modern jobs. 相似文献
57.
Bisphenol S has been introduced into some industrial applications and it may act as a xeno-estrogen that can alter endocrine functions and reproduction. The present study was carried out to examine the effect of bisphenol S exposure on oxidative stress, generation of reactive oxygen species, and DNA integrity in rat spermatozoa in vitro and daily sperm production and sperm DNA damage in vivo. Sperm were incubated with bisphenol S at concentrations of 0.5, 1, 10, and 100 µg/L. At the highest concentration, bisphenol S induced formation of reactive oxygen species, caused lipid peroxidation, affected superoxide dismutase levels, and increased DNA fragmentation. Adult rats were exposed to doses of 0.5, 5, 25, and 50 µg/kg/d for 28 days. Decrease in daily sperm production and an increase in sperm DNA damage was observed at the highest dose in the 50 µg/kg/d treated group, but sperm motility was not reduced. 相似文献
58.
M. Jason Todd George Vellidis R. Richard Lowrance Catherine M. Pringle 《Journal of the American Water Resources Association》2009,45(6):1493-1507
Todd, M. Jason, George Vellidis, R. Richard Lowrance, and Catherine M. Pringle, 2009. High Sediment Oxygen Demand Within an Instream Swamp in Southern Georgia: Implications for Low Dissolved Oxygen Levels in Coastal Blackwater Streams. Journal of the American Water Resources Association (JAWRA) 45(6):1493‐1507. Abstract: Sediment oxygen demand (SOD) is considered a critical and dominant sink for dissolved oxygen (DO) in many river systems including blackwater streams and is often poorly investigated or roughly estimated in oxygen budgets. The purposes of this study are to (1) characterize and document the magnitude and variability of SOD in representative instream swamps found on the Georgia Coastal Plain; (2) predict SOD from more readily measured parameters such as soil, sediment, and litter organic carbon; and (3) obtain an accurate representation of SOD values within this understudied habitat to help improve water quality models and the continued development of DO as an appropriate water quality standard. Results show SOD rates ranging from 0.491 to 14.189 g O2/m2/day, up to 18 times higher than values reported for southeastern sandy‐bottomed streams and suggest that instream swamps are repositories of large amounts of organic matter and are thus areas of intense oxygen demand and a major factor in determining the oxygen balance of the watershed as a whole. These areas of intense oxygen demand in relatively unimpacted areas indicate that low DO concentrations may be a natural phenomenon. SOD rates were significantly correlated (alpha = 0.05) with a number of sediment parameters, with organic carbon and total organic carbon being the best predictors of SOD rate. When developing water quality models, managers should pay closer attention to the influence of SOD as it plays a critical role in determining DO levels within instream swamps and the river system. 相似文献
59.
Nickitas Georgas Srinivasan Rangarajan Kevin J. Farley Sarath Chandra K. Jagupilla 《Journal of the American Water Resources Association》2009,45(3):715-733
Abstract: The Generalized Watershed Loading Functions (GWLF) model and its ArcView interface (AVGWLF) were used to estimate and examine the components of the total nitrogen (TN) nonpoint source (NPS) load generated within New York and Connecticut (CT) watersheds surrounding Long Island Sound (LIS, the Sound). The majority of data used as model inputs were generally available from online sources, and the work involved an overall calibration to streamflow and TN data in accordance with generic guidelines recommended in the GWLF manual. The GWLF model performance for three calibration and two validation watersheds in CT was compared with results of a detailed model, Hydrological Simulation Program in Fortran, developed in a previous study. The results of the application illustrate the usefulness of the relatively simpler, less parameter‐intensive GWLF model in performing exploratory loading analysis in preparation for adaptive nutrient management in the LIS watersheds. The presented methodology is valuable for identification of priority watersheds for NPS pollution reduction and also for planning‐level evaluation of best management practices to achieve the desired reductions. It is estimated that ground‐water base flow may be the largest pathway for NPS TN to the Sound, contributing about 54% of the total NPS TN load, a finding with significant implications for LIS total maximum daily load reduction scenarios. In addition to ground water, septic systems are estimated to contribute about 17% of the total load, with the remaining TN load being mostly runoff from urban (17%), agricultural (5%), and low impact (e.g., forest) areas (6%). 相似文献
60.
1997年6月5日,大连市成为全国首批在新闻媒体中发布城市空气质量周报的城市之一,1998年5月15日又在全国率先发布城市空气质量日报.文章以空气质量周(日)报的发布为切入点,全面论述其良好的社会效益、明显的环境效益及潜在的经济效益.根据环境质量的消费性,结合大连的实际,提出环境信息网络是建立面向公众的环境信息体系最便捷的途径. 相似文献