Effect of Temperature on Survival of Airborne Mycoplasma pneumoniae

Aerosols of Mycoplasma pneumoniae were prepared at each of eight relative humidities between 0 and 85% and at five separate temperatures between 10 and 43 C. Survival of these organisms was found to be a function of both relative humidity and temperature. However, the temperature response was mediated by humidity in that the effects of temperature could be observed only if some water vapor was present. At all temperatures, survival of M. pneumoniae in aerosols was found to be best at the extremes of relative humidity. The effects of temperature were such that irrespective of relative humidity an increase in temperature resulted in a decreased airborne survival time.     

基于SVM和MPC的数字蚯蚓生物反应器温度及相对湿度动态预测控制

为实现自动控制蚯蚓生物处理反应器处理城市污泥过程中温度和相对湿度, 采用SVM(support vector machine)技术结合MPC(model predictive control)模型控制技术建立自动控制模型,准确调节蚯蚓反应器内强耦合的温度和相对湿度,在预定时间有效地控制实际温度和相对湿度达到预设目标。     

温湿度对稻纵卷叶螟卵的联合作用

为了探讨温湿度在稻纵卷叶螟Cnaphalocrocis medinalis （Guenée）种群发展中的作用, 通过室内实验调查了不同温度和湿度组合下该蛾卵的发育历期、 胚胎发育情况、 孵化率和卵粒重量的变化。结果表明： 在相同温度下卵历期随相对湿度的增大而缩短, 孵化率随相对湿度的加大而提高。在22℃下低于46%的相对湿度显著降低了卵的孵化率, 而在25～34℃下低于66%的相对湿度会引起孵化率的显著降低, 37℃下卵无论在何种湿度中均不能孵化。在50%左右的低湿条件下, 温度高于28℃后卵也不能孵化。温度在22～31℃和相对湿度在77%～100%范围内, 卵的孵化率无显著差异, 这属于稻纵卷叶螟卵的适宜温湿度范围。稻纵卷叶螟卵的发育起点温度和有效积温分别为10.1±0.6℃和63.7±3.5日度。卵的孵化率（Y）与温湿系数（RH/T）间呈显著的逻辑斯蒂曲线关系Y=0.8662/[1+exp(17.4084-7.5714×RH/T)]。温湿系数在2.34以下时卵孵化率将低于50%, 而达到3.0左右时孵化率接近最高值。结论认为, 低湿造成的稻纵卷叶螟卵重量显著降低、 卵粒干瘪、 胚胎发育受阻是致死卵的主要原因。     

Boundaries for Biofilm Formation: Humidity and Temperature

Environmental conditions which define boundaries for biofilm production could provide useful ecological information for biofilm models. A practical use of defined conditions could be applied to the high-level nuclear waste repository at Yucca Mountain. Data for temperature and humidity conditions indicate that decreases in relative humidity or increased temperature severely affect biofilm formation on three candidate canister metals.     

Boundaries for biofilm formation: humidity and temperature

Environmental conditions which define boundaries for biofilm production could provide useful ecological information for biofilm models. A practical use of defined conditions could be applied to the high-level nuclear waste repository at Yucca Mountain. Data for temperature and humidity conditions indicate that decreases in relative humidity or increased temperature severely affect biofilm formation on three candidate canister metals.     

Direct transesterification of gases by "dry" immobilized lipase

Several different reactor configurations, including single pass, continuous recycle, and batch reactor modes, were used to investigate the effects of temperature and water activity, or relative humidity, on lipase-catalyzed, gas-phase transesterifications. Temperature and relative humidity were controlled both inside reactors and throughout the course of the reaction to account for and optimize their effects. Results indicated that, at low relative humidity, reaction rates increased with temperature up to 60 degrees C. However, when relative humidity was increased, a similar increase in temperature resulted in the loss of nearly all enzyme activity. These results are consistent with the idea that enzymes without free water are more thermally stable. Furthermore, at constant ambient temperatures, production increased dramatically with an increase in relative humidity, confirming the idea that an increase in water activity increases catalytic activity. A mass balance performed on reactors at higher relative humidity revealed that hydrolysis (rather than transesterification) of the ester substrate could significantly decrease product yields.     

Anthesis and pollen dispersal of holcus lanatus L. and Festuca rubra L. in relation to climate factors

Anthesis and pollen dispersal of H. lanatus and F. rubra were related to climate factors during a field investigation on Schiermonnikoog. In both species the anthesis showed a diurnal periodicity and could be connected to air temperature, relative air humidity, and light intensity. In the pollen release of both species no daily periodicity was found. This pollen release appears to be dependent on neither the temperature nor the light intensity. It could be related to only one of the measured climate factors, viz. the relative air humidity. It was discussed that anthesis is an active process based on physiological and ecological properties of the plant, whereas the pollen dispersal is only a mechanical process.     

Response of Tomato Sugar and Acid Metabolism and Fruit Quality under Different High Temperature and Relative Humidity Conditions

The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture. However, there is little information about the precise interaction between them on tomato fruit quality. The objectives of this study were to explore the effects of the combined stress of high temperature and relative humidity on the sugar and acid metabolism and fruit quality of tomato fruits, and to determine the best relative air humidity for fruit quality under high temperature environments. Four temperature treatments (32°C, 35°C, 38°C, 41°C), three relative air humidity (50%, 70%, 90%) and four duration (3, 6, 9, 12 d) orthogonal experiments were conducted, with 28°C, 50% as control. The results showed that under high temperature and relative air humidity, the activity of sucrose metabolizing enzymes in young tomato fruits changed, which reduced fruits soluble sugar content; in addition, enzyme activities involved phosphopyruvate carboxylase (PEPC), mitochondria aconitase (MDH) and citrate synthetase (CS) increased which increased the content of organic acids (especially malic acid). Eventually, vitamin C, total sugar and sugar-acid ratio decreased significantly, while the titratable acid increased, resulting in a decrease in fruit flavor quality and nutritional quality in ripe fruit. Specifically, a temperature of 32°C and a relative air humidity of 70% were the best cultivation conditions for tomato reproductive growth period under high temperature. Our results indicating that fruit quality reduced under high temperature at the flowering stage, while increasing the relative air humidity to 70% could alleviate this negative effect. Our results are benefit to better understand the interaction between microclimate parameters under specific climatic conditions in the greenhouse environment and their impact on tomato flavor quality.     

The Evaporative Function of Cockroach Hygroreceptors

Insect hygroreceptors associate as antagonistic pairs of a moist cell and a dry cell together with a cold cell in small cuticular sensilla on the antennae. The mechanisms by which the atmospheric humidity stimulates the hygroreceptive cells remain elusive. Three models for humidity transduction have been proposed in which hygroreceptors operate either as mechanical hygrometers, evaporation detectors or psychrometers. Mechanical hygrometers are assumed to respond to the relative humidity, evaporation detectors to the saturation deficit and psychrometers to the temperature depression (the difference between wet-bulb and dry-bulb temperatures). The models refer to different ways of expressing humidity. This also means, however, that at different temperatures these different types of hygroreceptors indicate very different humidity conditions. The present study tested the adequacy of the three models on the cockroach’s moist and dry cells by determining whether the specific predictions about the temperature-dependence of the humidity responses are indeed observed. While in previous studies stimulation consisted of rapid step-like humidity changes, here we changed humidity slowly and continuously up and down in a sinusoidal fashion. The low rates of change made it possible to measure instantaneous humidity values based on UV-absorption and to assign these values to the hygroreceptive sensillum. The moist cell fitted neither the mechanical hygrometer nor the evaporation detector model: the temperature dependence of its humidity responses could not be attributed to relative humidity or to saturation deficit, respectively. The psychrometer model, however, was verified by the close relationships of the moist cell’s response with the wet-bulb temperature and the dry cell’s response with the dry-bulb temperature. Thus, the hygroreceptors respond to evaporation and the resulting cooling due to the wetness or dryness of the air. The drier the ambient air (absolutely) and the higher the temperature, the greater the evaporative temperature depression and the power to desiccate.     

基于冠层温湿度模型的日光温室黄瓜霜霉病预警方法

利用温室环境参数构建室内微环境模拟模型,并结合温室病害模型进行预警,便于开展病害生态防治,以减少农药使用,从而保护温室生态环境和保证农产品质量安全.本文利用温室内能量守恒原理和水分平衡原理,构建了日光温室冠层叶片温度和空气相对湿度模拟模型.叶片温度模拟模型考虑了温室内植物与墙体、土壤、覆盖物之间的辐射热交换,以及室内净辐射、叶片蒸腾作用引起的能量变化;相对湿度模拟模型综合了温室内叶片蒸腾、土壤蒸发、覆盖物与叶面的水汽凝结引起的水分变化.将温湿度估计模型输出值作为参数,输入黄瓜霜霉病初侵染和潜育期预警模型中,估计黄瓜霜霉病发病日期,并与田间观测的实际发病日期比较.试验选取2014年9月和10月的温湿度监测数据进行模型验证,冠层叶片温度实际值与模拟值的均方根偏差（RMSD)分别为0.016和0.024 ℃,空气相对湿度实际值与模拟值的RMSD分别为0.15%和0.13%.结合温湿度估计模型结果表明,黄瓜病害预警系统预测黄瓜霜霉病发病日期与田间调查发病日期相吻合.本研究可为黄瓜日光温室病害预警模型及系统构建提供微环境数据支持.     

Urban heat island effects on moss gardens in Kyoto,Japan

Urban heat islands (UHIs) represent a serious problem for urban biodiversity and landscapes. The impact of UHIs on Japanese gardens are of particular concern because these gardens use moss as a ground cover, and moss can be strongly affected by UHIs due to their sensitivity to drought stress. We studied 17 historical gardens in Kyoto, Japan, and propose an effective management strategy for moss gardens that takes into account the influence of UHIs on these gardens. The study sites included gardens covered by large patches of hygrophilous moss, gardens covered by mosses including small patches of hygrophilous moss, gardens covered by relatively drought-resistant moss, and gardens with small patches of mosses. We measured temperature and relative humidity within the gardens and determined the surrounding land-use types. A comparison of microclimates showed significant differences among garden types. Hygrophilous gardens had the lowest temperature and highest relative humidity, whereas gardens with small patches of moss had the highest temperature and lowest relative humidity. Using structural equation models, we determined that urbanization within 1000 m from the gardens increased temperature and decreased relative humidity, strongly affecting the type of garden. These effects could be attributed to the sensitivity of mosses to changes in microclimate caused by UHIs. Taken together, the results indicate that urban planning—e.g., increasing green space—within 1000 m of moss gardens can maintain those gardens by mitigating the influence of UHIs.

     

Diurnal flight behavior of Ichneumonoidea (Insecta: Hymenoptera) related to environmental factors in a tropical dry forest

The biology and behavior of insects are strongly influenced by environmental conditions such as temperature and precipitation. Because some of these factors present a within day variation, they may be causing variations on insect diurnal flight activity, but scant information exists on the issue. The aim of this work was to describe the patterns on diurnal variation of the abundance of Ichneumonoidea and their relation with relative humidity, temperature, light intensity, and wind speed. The study site was a tropical dry forest at Ría Lagartos Biosphere Reserve, Mexico; where correlations between environmental factors (relative humidity, temperature, light, and wind speed) and abundance of Ichneumonidae and Braconidae (Hymenoptera: Ichneumonoidea) were estimated. The best regression model for explaining abundance variation was selected using the second order Akaike Information Criterion. The optimum values of temperature, humidity, and light for flight activity of both families were also estimated. Ichneumonid and braconid abundances were significantly correlated to relative humidity, temperature, and light intensity; ichneumonid also showed significant correlations to wind speed. The second order Akaike Information Criterion suggests that in tropical dry conditions, relative humidity is more important that temperature for Ichneumonoidea diurnal activity. Ichneumonid wasps selected toward intermediate values of relative humidity, temperature and the lowest wind speeds; while Braconidae selected for low values of relative humidity. For light intensity, braconids presented a positive selection for moderately high values.     

Response of Callosobruchus maculatus (F.) to varying temperature and relative humidity under laboratory conditions

The effect of temperature and relative humidity were determined on the development of Callosobruchus maculatus (F.) on stored bean (Vigna unguiculata) seeds exposed to five temperatures (20, 25, 30, 35 and 40 °C) and six relative humidity levels (40, 50, 60, 70, 80 and 90%). Oviposition and total adult progeny responded in a curvilinear pattern to temperature and relative humidity while developmental period presented a linear response. Egg laying (117.33 ± 3.21) and adult emergence (35.00 ± 1.70) were least at 20 °C and 90% R.H. but those showed the optimal values at 30 °C and 70% R.H. The implication of these findings is that the growth attributes of C. maculatus relate with the weather variables studied in a curvilinear manner and thus quadratic equations generated could be used for the prediction of optimum temperature and relative humidity in a given area for the management of C. maculatus in stored beans.     

Forecasting model of bacterial leaf spot disease of mulberry caused by Xanthomonas campestris pv. mori

In order to develop weather-based forecasting model of bacterial leaf spot (BLS) disease of mulberry caused by Xanthomonas campestris pv. mori, weekly disease severity data were recorded for three years on the ruling cultivar S-1. Daily meteorological data viz. maximum temperature, minimum temperature, maximum relative humidity, minimum relative humidity, rainfall and number of rainy days were also recorded. It was observed that BLS appeared in April/May and continued up to November with maximum severity in July. The correlation coefficient between disease severity and meteorological parameters revealed that the BLS disease severity has significant positive correlation with minimum temperatures, maximum and minimum relative humidity, rainfall and number of rainy days and negative correlation with maximum temperature. Multiple regressions analysis revealed that average of maximum temperature, minimum temperature and rainfall of preceding seven days and maximum relative humidity, minimum relative humidity of previous 9–15 days was found to maximally influence BLS disease severity. The contribution of the meteorological factors was found to be highest of minimum temperature (40.65%) followed by maximum temperature (24.20%), maximum relative humidity (16.41%), minimum relative humidity (8.07%), rainfall (5.29%) and number of rainy days (5.38%).     

Quantitative Studies on Fabrics as Disseminators of Viruses: II. Persistence of Poliomyelitis Virus on Cotton and Wool Fabrics

The length of time that poliovirus could be recovered from wool gabardine and blanket, and from cotton sheeting, terry cloth, and knit jersey fabrics was determined under conditions of controlled temperature and humidity (25 C in 35 and 78% relative humidities). Three types of exposure of the fabrics to viruses were used: direct contact, aerosol, and virus-containing household dust having a high content of textile fibers. When held in 35% relative humidity, virus persisted for 20 weeks on wool fabrics, but only 1 to 4 weeks on cotton fabrics. At this relative humidity, virus titers on wool fabrics decreased rapidly to low but detectable levels which persisted for long periods of time, whereas in 78% relative humidity the decrease in virus titer was less rapid, but the period of viral persistence was shorter. Generally, virus titers on cotton fabrics held in both relative humidities decreased exponentially to an undetectable level. The method of exposure to virus had a definite effect on the duration of viral persistence on a given fabric. Virus contained in household dust was least stable.     

丘陵区生态农业旅游的垂直景观生态研究

针对城郊丘陵区的地貌特征,生态农业旅游景观应按坡度和等高线布置,形成山顶水保林带、坡上桃树带、坡中枇杷带、坡下特种瓜果带、山底特色水域带的垂直生态景观模式。这种模式不仅具有良好的景观效果,也产生了很好的生态效益。试验区植被覆盖率显著提高,物种多样性得到了恢复,景观林带内的气温和土温降低、温度日变幅减少、空气相对湿度增加,这种效果由弱至强依次表现为农作地、水保林、经果林。果园自然生草、种植牧草后有利于降低土壤和空气温度、减少温度日变幅、增加空气相对湿度和防治水土流失的效果。     

Relative humidity is a key factor in the acclimation of the stomatal response to CO(2)

Previous work has shown that stomata of growth chamber-grown Vicia faba leaves have an enhanced CO2 response when compared with stomata of greenhouse-grown plants. This guard cell response to CO2 acclimatizes to the environmental conditions on the transfer of plants between the two environments. In the present study, air relative humidity is identified as a key environmental factor mediating the changes in stomatal sensitivity to CO2. In the greenhouse environment, elevation of relative humidity to growth chamber levels resulted in an enhanced CO2 response, whereas a reduction in the light level to that comparable to growth chamber conditions had no effect on stomatal CO2 sensitivity. The transfer of plants between humidified and normal greenhouse conditions resulted in an acclimation response with a time-course matching that previously obtained in transfers of plants between greenhouse and growth chamber environments. The high stomatal sensitivity to CO2 of growth chamber-grown plants could be reduced by lowering growth chamber relative humidity and then restored with its characteristic acclimation time-course by an elevation of relative humidity. Leaf temperature was unchanged during this restoration, eliminating it as a primary factor in the acclimation response. Humidity regulation of stomatal CO2 sensitivity could function as a signal for leaves inside dense foliage canopies, promoting stomatal opening under low light, low CO2 conditions.     

Microclimatic adaptation and differences in food consumption and assimilation efficiency of different shell colour morphs of the land snail Arianta arbustorum

Food consumption and assimilation efficiency of different shell colour morphs adapted to various microclimatic conditions were determined. Five-factor analysis of variance (adaptation temperature, relative humidity, phenotypic shell colour, age class and time of acclimatization) was used. There are differences between different levels of adaptation temperature and relative humidity in the effect on food consumption in the two morphs. The interaction of these two factors is also significant. There is no effect of the phenotypic shell colour on the food consumption, but there is a relation between shell colour and adaptation temperature. Food consumption is greater in the juveniles. The interactions between age class and adaptation temperature or relative humidity are relevant. Acclimatization to these conditions shows a highly significant effect on the food consumption. The brown and yellow morphs of Arianta arbustorum consumed different amounts of food in relation to the adaptation temperature.
Assimilation efficiency is independent of temperature but declines at high relative humidity. There is a relation between adaptation temperature and relative humidity, but not between the phenotypic shell colour and age class factors. The yellow morphs show higher assimilation efficiencies than the brown morphs during cold adaptation to 5 °C and at the highest level of relative humidity (98%).     

夏季城市河流宽度对绿地温湿效益的影响

城市河流是城市生态系统中重要的组成部分,对城市生态环境的改善发挥着重要作用.利用小尺度定量测定的技术方法,分析了北京市三环至五环附近7条不同宽度城市河流对其旁侧绿地温湿效益的影响.结果表明： 城市河流宽度是影响绿地温湿效应的重要因素.当河流宽度为8 m时,绿地具有一定的增湿效应,但降温效果不明显;当河流宽度为14～33 m时,绿地降温、增湿效果明显;当河流宽度超过40 m时,绿地降温、增湿效果显著且趋于稳定.7条河流旁侧绿地与各自对照间的温、湿度差异均达到显著水平,且显著发挥温湿效益的河流宽度为44 m.河流旁侧绿地夏季温度（x）、湿度（y）关系的回归方程为y=173.191-3.247x,相对湿度每升高1.0%,温度降低约0.3 ℃.