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681.
Suppression pheromone and cockroach rank formation   总被引:1,自引:0,他引:1  
Although agonistic behaviors in the male lobster cockroach (Nauphoeta cinerea) are well known, the formation of an unstable hierarchy has long been a puzzle. In this study, we investigate how the unstable dominance hierarchy in N. cinerea is maintained via a pheromone signaling system. In agonistic interactions, aggressive posture (AP) is an important behavioral index of aggression. This study showed that, during the formation of a governing hierarchy, thousands of nanograms of 3-hydroxy-2-butanone (3H-2B) were released by the AP-adopting dominant in the first encounter fight, then during the early domination period and that this release of 3H-2B was related to rank maintenance, but not to rank establishment. For rank maintenance, 3H-2B functioned as a suppression pheromone, which suppressed the fighting capability of rivals and kept them in a submissive state. During the period of rank maintenance, as the dominant male gradually decreased his 3H-2B release, the fighting ability of the subordinate gradually developed, as shown by the increasing odds of a subordinate adopting an AP (OSAP). The OSAP was negatively correlated with the amount of 3H-2B released by the dominant and positively correlated with the number of domination days. The same OSAP could be achieved earlier by reducing the amount of 3H-2B released by the dominant indicates that whether the subordinate adopts an offensive strategy depends on what the dominant is doing.  相似文献   
682.
饮用水消毒副产物分析及相关研究进展   总被引:8,自引:0,他引:8  
饮用水消毒副产物(DBPs)是消毒剂和一些天然有机物(NOM)反应生成的化合物,主要包括三卤甲烷(THMs)、卤代G@(HAAs)、卤代乙腈(HANs)和致诱变化舍物(MX)4类。本文针对氯、氯胺、二氧化氯、臭氧4种主要消毒方式产生的消毒副产物,讨论了有关分析技术的发展过程,从DBPs的前处理技术、分析技术等角度,介绍了DBPs研究领域近期所取得的进展,并展望了今后研究的发展方向。  相似文献   
683.
Past arsenic exposure was found associated with increased incidence of type 2 diabetes. However, the mechanisms remain unclear. Metabolic syndrome has been shown as a strong predictor for diabetes occurrence. We aimed at examining the association of inorganic arsenic exposure and the prevalence of metabolic syndrome. The authors recruited 660 age and gender stratified random population of residents in central Taiwan during 2002-2003. They received home interviews and health examinations at local health care units, where blood and hair specimens were collected. Hair arsenic (H-As) concentrations were determined by inductively coupled plasma-mass spectrometry. Metabolic syndrome was defined as the presence of three or more of the following risk factors: elevated levels of blood pressure, plasma glucose, and triglycerides, also the body mass index, and reduced high-density lipoprotein. Prevalence of metabolic syndrome increased from the 2nd tertile (0.034 ug/g) of H-As levels (odds ratio=2.54, 95% confidence interval: 1.20-5.39, p=0.015) after the adjustment for age, gender, occupation and life styles including cigarette smoking. We further found linear relation between H-As concentrations and increased levels of plasma glucose and lipids, and blood pressures. This first report may help identify modifiable factors associated with diabetogenesis and cardiovascular disease progression and thus be worth following for community health.  相似文献   
684.
本文以呼和浩特市为研究对象,利用遥感(RS技术)、地理信息系统(GIS技术)以及全球定位系统技术(GPS技术)——简称3S技术,对呼和浩特市2000、2004年遥感影像进行了综合技术处理,获得2期土地利用现状图,据此对呼和浩特市土地利用变化幅度及变化速度、土地利用变化程度、土地利用变化空间动态进行了分析,为区域土地资源科学管理及实现区域土地资源可持续利用提供科学依据。  相似文献   
685.
In this study, paddy fields in Jilin province which are flooded parcel of arable lands used for growing rice (Oryza sativa Linn.) were selected as the object. Long-term exploitation of paddy fields led to variations of soil organic carbon (SOC) and green house gases (GHGs) emissions which might contribute to global warming. In order to calculate the amount of global warming potentials (GWPs) of emissions from ricepaddies and find the correlations among rice yield, SOC storage and GWP, DeNitrification-DeComposition (DNDC) model was used to simulate SOC densities and fluxes of main GHGs emitted from paddy fields. After verification, simulation results were used to calculate SOC storages and 100-year GWPs from 1949 to 2009. Results indicated that SOC densities in depths of 0–10 cm, 10–20 cm and 20–30 cm all kept increasing. Average methane (CH4) and nitrous oxide (N2O) fluxes were 278.55 kg carbon (kgC) ha−1 a−1 and 2.22 kg nitrogen (kgN) ha−1 a−1. The SOC storage (0–30 cm) had increased from 3.96 × 109kgC in 1949 to 47.85 × 109kgC in 2009. In addition, GWP emission was increasing exponentially in the past 61 years, from 0.16 × 106 Mg carbon dioxide equivalents (CO2-equivalents) to 66.36 × 106 Mg CO2-equivalents. Both SOC storage and GWP presented obviously linear relation to rice yields. Overall, the research suggested that long-term rice yields could be used to estimate the SOC storage and GWP variations.  相似文献   
686.
介绍了液化烃的特性及主要火灾爆炸伤害模型,分析了诱发火灾爆炸的原因,并从本质化安全技术角度,提出了前期管理无缺陷的主要对策措施。  相似文献   
687.
自然环境谱编制方法研究   总被引:7,自引:6,他引:1  
针对装备(产品)在服役过程中所遭受的自然环境开展了自然环境谱编制方法研究,给出了自然环境谱的定义和编制程序,提出了盐雾和工业废气环境的判定标准,制定了适用于我国各种大气环境场地自然环境谱的编制方法,并举例编制了某地域的自然环境谱.  相似文献   
688.
以聚乙烯亚胺、巯基乙酸为原料,通过酰胺化反应合成了一种新型高分子重金属絮凝剂巯基乙酰聚乙烯亚胺(MAPEI),研究其处理含镉废水的性能,并对几个影响因素进行了考察。实验结果表明:①该絮凝剂对Cd2+有很好的捕集性能,最高去除率可达99.9%以上;②水中常见阳离子Na+、K+、Mg2+对Cd2+的去除起促进作用;③水中常见阴离子C l-、SO42-、NO3-对Cd2+的去除也起促进作用;④pH值在6.0至8.0范围内变化时,pH值越高去除Cd2+的效果越好;⑤Cd2+和致浊物质共存时,会相互促进彼此的去除。  相似文献   
689.
在结合实际确定陕西省二噁英的主要排放源及其排放因子基础上,采用国际通用的气体排放量计算法估算了陕西省2000年-2008年的二噁英年排放量,并就排放量的构成和变化趋势进行分析。结果显示:二噁英的年排放总量呈增长趋势,介于27.67 98.39 g TEQ之间;能源消耗产生的二噁英居于首位,其排放量约占总排放量的50%。工业燃料燃烧和工业生产过程所排放的二噁英占年排放量的60%以上,控制工业污染源的二噁英排放势在必行。  相似文献   
690.
Studies on mortality attributed to tropical cyclones often concern large-scale disasters. Attention is rarely paid to small-scale mortality over the long term. To understand the relationship between the environment and the behavior that contributes to mortality, this article uses a classification table to review the 1556 deaths attributed to tropical cyclones, named typhoons, in Taiwan during the period 2000–2014. The results demonstrate that the majority of outdoor deaths are associated with work-related activities, while most indoor deaths occur during non-work-related activities. Taking action, such as stopping the car on a bridge if the tail lights of a vehicle in front disappear, and not walking on the roadside when the road is flooded by muddy water, may help to reduce the likelihood of typhoon-attributed death. The findings also help to dispel four myths associated with typhoon-attributed mortality.  相似文献   
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