高密度中心城区蓝绿空间冷岛效应及其影响因素——以北京五环路以内地区为例

蓝绿空间作为城市绿色基础设施的重要组成部分，对促进城市热环境健康、改善局地微气候具有重要作用。利用Landsat 8遥感影像、土地利用等数据，基于辐射传输方程算法、K均值聚类算法、相关性分析等方法，量化了典型的高密度中心城区--北京五环快速路以内地区的1199块1hm²以上的蓝绿空间冷岛效应的表征指标，并分析与蓝绿空间规模、形状复杂度、景观组成、环境组成、植被覆盖等要素的相关关系，还根据蓝绿空间的不同降温特性进行分类，探讨每类蓝绿空间在缓解高密度中心城区热岛效应中的独特作用、优势与机制。结果表明：（1）蓝绿空间的规模、形状复杂度、景观组成等景观要素与冷岛效应的关系显著，如总面积、绿地面积和水体面积与降温幅度、降温范围、降温服务呈显著正相关，与降温效率和降温速率呈显著负相关；周长与降温范围、降温服务呈显著正相关，与降温效率和速率呈显著负相关；周长面积比与降温幅度和降温服务呈显著负相关，与降温效率和蓝绿空间自身温度呈显著正相关，而形状指数则与降温范围和降温服务呈显著正相关。（2）蓝绿空间的环境要素与冷岛效应也存在相关关系。蓝绿空间之间会产生冷岛效应的协同与促进现象，蓝绿空间降温范围内的其他蓝绿空间的总面积与该蓝绿空间的降温幅度、降温范围、降温服务和辐射距离呈显著正相关，与蓝绿空间自身温度呈显著负相关。（3）蓝绿空间的总面积、水体面积、周长与降温幅度之间，周长面积比与降温效率之间存在阈值，为节约土地资源、保证降温效果，建议不应过多超过阈值。（4）基于蓝绿空间在降温幅度、效率、辐射距离等方面的差异，将蓝绿空间划分为4类。高密度中心城区蓝绿空间规划建设应充分评估区域降温需求，了解蓝绿空间降温现状，合理配置具有不同降温特性和优势的蓝绿空间，在土地和资金有限的情况下，充分发挥各类蓝绿空间的冷岛效应。本研究有助于政府和规划师摸清当前蓝绿空间冷岛效应的现状、问题和发展潜力，对理论和实践具有一定参考意义。     

Spatiotemporal distribution of growth releases and suppressions along a landslide body

Our study analyzes the growth response (release or suppression) of Norway spruce trees growing along a landslide zone in eastern Czech Republic. A total of one hundred and eighty-six increment cores were extracted from Norway spruce (Picea abies (L.) Karst.) individuals, which were affected by two different disturbances, the Girová landslide in May 2010 and an anthropogenic cut-off in the neighborhood of the landslide later the same year. Growth changes were analysed in three zones that were defined according to the type of effect the disturbance had on the surrounding vegetation. The aims of our study are to (i) detect growth changes in trees that survived the disturbances in 2010, (ii) evaluate the delay time of the growth reaction to the disturbances, (iii) compare how growth changes differed in response to the two different disturbance types (natural landslide vs. anthropogenic harvesting and deforestation), and (iv) investigate spatio-temporal differences in the growth changes. Our results indicate that tree growth changed in response to the altered environmental conditions following the 2010 disturbances. The changes vary depending on the intensity of the disturbance and its effect on the forest stand. Trees in Zone 1 responded with a slight growth release (14.6 % of responding trees), which was strongest after 2013. However, growth suppression (85.4 %) was the dominant reaction in Zone 1; with the majority of trees showing growth suppression in 2014, four years after the events. The strongest and most abrupt growth release (66.1 %) occurred in Zone 2 in 2011, after a one-year delay. Since 2010, we have observed a trend of growth suppression (33.9 %) in this zone. In Zone 3, following a one-year delay, growth release has occurred gradually in about a third of the trees (37.0 %). The majority of trees in this zone have responded with growth suppression (63.0 %) in 2010 and with a three-year delay after 2013. We also found differences in how tree growth responds to anthropogenic and landslide disturbances, as well as spatio-temporal differences related to the extent of post-disturbance changes.     

Optimal reproductive phenology under size‐dependent cannibalism

Intra‐cohort cannibalism is an example of a size‐mediated priority effect. If early life stages cannibalize slightly smaller individuals, then parents face a trade‐off between breeding at the best time for larval growth or development and predation risk from offspring born earlier. This game‐theoretic situation among parents may drive adaptive reproductive phenology toward earlier breeding. However, it is not straightforward to quantify how cannibalism affects seasonal egg fitness or to distinguish emergent breeding phenology from alternative adaptive drivers. Here, we devise an age‐structured game‐theoretic mathematical model to find evolutionary stable breeding phenologies. We predict how size‐dependent cannibalism acting on eggs, larvae, or both changes emergent breeding phenology and find that breeding under inter‐cohort cannibalism occurs earlier than the optimal match to environmental conditions. We show that emergent breeding phenology patterns at the level of the population are sensitive to the ontogeny of cannibalism, that is, which life stage is subject to cannibalism. This suggests that the nature of cannibalism among early life stages is a potential driver of the diversity of reproductive phenologies seen across taxa and may be a contributing factor in situations where breeding occurs earlier than expected from environmental conditions.     

Identification of causal effects using instrumental variables in randomized trials with stochastic compliance

In randomized trials with imperfect compliance, it is sometimes recommended to supplement the intention‐to‐treat estimate with an instrumental variable (IV) estimate, which is consistent for the effect of treatment administration in those subjects who would get treated if randomized to treatment and would not get treated if randomized to control. The IV estimation however has been criticized for its reliance on simultaneous existence of complementary “fatalistic” compliance states. The objective of the present paper is to identify some sufficient conditions for consistent estimation of treatment effects in randomized trials with stochastic compliance. It is shown that in the stochastic framework, the classical IV estimator is generally inconsistent for the population‐averaged treatment effect. However, even under stochastic compliance, with certain common experimental designs the IV estimator and a simple alternative estimator can be used for consistent estimation of the effect of treatment administration in well‐defined and identifiable subsets of the study population.     

Xanthine oxidoreductase: A journey from purine metabolism to cardiovascular excitation-contraction coupling

Xanthine oxidoreductase (XOR) is a ubiquitous complex cytosolic molybdoflavoprotein which controls the rate limiting step of purine catabolism by converting xanthine to uric acid. It is known that optimum concentrations of uric acid (UA) and reactive oxygen species (ROS) are necessary for normal functioning of the body. The ability of XOR to perform detoxification reactions, and to synthesize UA and reactive oxygen species (ROS) makes it a versatile intra- and extra-cellular protective “housekeeping enzyme”. It is also an important component of the innate immune system. The enzyme is a target of drugs against gout and hyperuricemia and the protein is of major interest as it is associated with ischemia reperfusion (I/R) injury, vascular disorders in diabetes, cardiovascular disorders, adipogenesis, metabolic syndrome, cancer, and many other disease conditions. Xanthine oxidoreductase in conjugation with antibodies has been shown to have an anti-tumor effect due to its ability to produce ROS, which in turn reduces the growth of cancer tissues. Apart from this, XOR in association with nitric oxide synthase also participates in myocardial excitation-contraction coupling. Although XOR was discovered over 100 years ago, its physiological and pathophysiological roles are still not clearly elucidated. In this review, various physiological and pathophysiological functional aspects of XOR and its association with various forms of cancer are discussed in detail.     

Effect of Experimental Diabetic Retinopathy on the Non-Image-Forming Visual System

Since the serum level of the enzyme creatine (phospho)kinase (CPK) is frequently used for diagnostic purposes and since circadian variations of this parameter have been observed under different stress conditions, it had to be determined whether they are induced by an endogenous circadian rhythm or whether they are activity-related masking effects. For this purpose, 15 untrained male test persons were examined for a period of 25h each under different conditions: lying constantly in a climatic chamber, everyday activity conditions, resting conditions with intermittent bicycle ergometer tests (1.4 W/kg body weight) between 09:00 and 11:30 or between 15:00 and 17:30. In addition, 5 sportsmen were included in the study under resting conditions and the bicycle ergometer tests in the forenoon. The serum CPK was determined at intervals of 2h or 4h, respectively. Under constant resting conditions, the mean serum CPK level decreased continuously (p <. 001, repeated measures analysis of variance [Rep. Mes. ANOVA]), and the final values amounted to approximately 80% of the initial values. In contrast, under everyday conditions, the mean CPK level rose during the activity phase and decreased again to below the initial values during subsequent rest (p <. 001, Rep. Mes. ANOVA). In the ergometer tests, the CPK blood level rose in each case after the activity phase and fell again continuously in the following resting period. However, in the calculation of the deviations from the linear trend, it was shown that certain daily variations in the CPK values can be detected under constant resting conditions; however, the amplitude was much smaller than the amplitude under everyday activity conditions. All in all, it can be stated that serum CPK levels are mainly dependent on the physical load conditions, and that the daily changes observed under everyday conditions disappear almost entirely under resting conditions. The daily variation of the serum creatine kinase level under everyday conditions can thus be regarded as a masking effect. These results are of practical significance for diagnosis to the extent that the physical activity that has taken place before the determination of the CPK level must be taken into account in the interpretation of the values. According to the results obtained so far, the CPK serum level may be used in chronobiology as an indicator of masking by physical activity. (Chronobiology International, 17(4), 583–590, 2000)     

A New Enzyme “Bilirubin Oxidase” Produced by Myrothecium verrucaria MT-1

The thermal degradation kinetics of pectin methylesterase (PME) from carrot and lettuce were studied. Fresh extracts were exposed to temperatures from 55 to 70 °C until the enzyme was inactivated. A model based on the presence of two forms of the enzyme, one active and one non-active, is proposed. The natural variability of the PME activity was taken into the model in the form of normally distributed random effects. The common model parameters obtained (cleavage constant (0.0395±0.0062 s^?1), degradation constant (0.556±0.112 s^?1), cleavage energy of activation (469±23 kJ mol^?1) and degradation energy of activation (488±18 kJ mol^?1)) show that the PME degradation kinetics of the two vegetables can be explained with a single set of parameters.     

Tracing the toxic ions of an endodontic tricalcium silicate-based sealer in local tissues and body organs

BackgroundThis study aimed to track the toxic ions released by MTA Fillapex, BioRoot RCS, and an experimental tricalcium silicate-based sealer (CEO) into local and distant tissues as well as to investigate their potential adverse effects. In addition, the chemical constituents of the sealers were also evaluated. The main components of the dry powders, pastes, and mixed sealers were characterized.Material and methodsDry powder and sealer discs were each set for 72 h and their main components were characterized by energy dispersive X-ray spectroscopy. Polyethylene tubes filled with sealers were used to measure silicon and calcium ions. Polyethylene tubes filled with sealers or empty tubes were implanted into the dorsal connective tissue of Wistar rats. On days 7, 15, 30, and 45, the animals were euthanized and their brains, livers, kidneys, and subcutaneous tissues were removed and processed to determine the concentrations of chromium, cobalt, copper, lead, iron, magnesium and nickel using an inductively coupled plasma optical emission spectrometer.ResultsThe main compounds in all sealers were carbon, oxygen, silicon, and calcium. MTA Fillapex release more Si while highest levels of Si were found in presence of BioRoot. The release of Si and Ca ions promoted by MTA Fillapex raise by time. No traces of cobalt, chromium, or magnesium were detected in any tissue. Irrespective of the sealer, no traces of copper and lead were found in the subcutaneous tissue; however, they were observed in the organs. The highest concentration of iron was identified in the liver. All sealers exhibited similar nickel traces in the brain, kidney, and liver except for MTA Fillapex, which demonstrated levels higher than CEO in the subcutaneous tissue on day 7. Tracing nickel ions over time revealed that lowest concentrations were found in subcutaneous tissue.ConclusionTaken together, our data demonstrate that CEOs have chemical compositions similar to those of other commercial sealers. Furthermore, none of them exhibited a threat to systemic health. Moreover, the minimal amounts of iron and nickel detected were not related to the sealers.