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1.
本文重点论述了苏胶地体内榴辉岩的四种产出形态,从岩石化学特点,微量元素的分馏及稀土元素富集或亏损等规律用六种以上的方法判别了不同产状榴辉岩的原岩性质;同时从区域变质环境、共生矿物、阳离子配位系数的相关性等方面,分析估算了榴辉岩相变质事件的Pt条件,以及后成碱性闪石榴辉岩产生的Pt条件,并同世界各地碱性闪石榴辉岩的成因作了广泛对比,概括了榴辉岩的成因环境等重大地质问题。  相似文献   

2.
Temperature is a major driver of biological phenomena, from metabolism to ecological interactions and rates of evolutionary diversification. However, species vary greatly in their thermal tolerance, as well as the temperature under which they perform best. This study aimed to investigate the effect of experimental manipulation of environmental temperatures on the individual mortality and phenotypic composition of colonies of Melipona interrupta. To fulfill these objectives, 30 colonies in equivalent developmental conditions were artificially subjected to different temperatures. Temperatures were monitored by thermo-hygrometers, and immature mortality and sex and caste ratios were observed in brood combs during 14 months. A strong effect of external temperature on immatures was detected on deviations from 28 to 30 °C (the natural average temperature inside the colony), causing an increase in mortality. Likewise, a significant effect of temperature on sex ratio was detected, with male:female ratio decreasing at temperatures below and above 28–30 °C. Lastly, there was no clear evidence for an effect of temperature on caste ratio, although queens appeared to become relatively more frequent at warmer temperatures. The results of this study allow us to conclude that anthropogenic changes, whose effect can be extrapolated to the similar natural changes, that modify the environmental temperatures to which M. interrupta colonies are exposed are likely to compromise their survival, mainly through individual mortality.  相似文献   

3.
In temperate climates, the initiation and termination of diapause synchronize the stress-tolerant stage with the stressful season and reproduction with the non-stressful season in many insects. Synchronization is often regulated by photoperiodism.Voltinism and the ultimate size of adults are also important determinants for their lifecycle, and different diapause stages and voltinism patterns are known in crickets.Here, we investigated the life history of the African cricket Gryllus argenteus from Malawi, which is a typical arid tropical highland. The climate is characterized by alternating arid and wet seasons, each of which lasts for half a year, and where the available heat mass is much less than lowlands at the same latitude. We first measured the nymphal duration at each rearing temperature and calculated the lower developmental threshold (t 0) to be 20.19 °C based on Ikemoto and Takai (2000) and 19.38 °C based on a conventional line-fitting method. These values are very high relative to many other insects. The local temperature in winter does not fall below 15 °C, but this is much higher than the lethal limit. This suggested that critical stress in this locality was not coldness but low precipitation in winter. We estimated, based both on local temperature change and the Ikemoto and Takai’s t 0, that G. argenteus required 3 years to complete its lifecycle unlike wet lowland species, where univoltinism or multi-voltinism are commonplace. Photoperiodism was observed in this species, but due to a lag between annual cycles in photoperiod, temperature, and humidity, photoperiodism alone cannot atune their lifecycle with local conditions.Synchronization in this species was achieved by three different adaptations: photoperiodism, high t 0, and large body size, which give it a long lifecycle. Although the species cannot achieve a univoltine lifecycle because of its high t0 value, it can escape from dry season by entering diapause at moderate temperatures, probably thereby achieving adaptive synchrony of lifecycle with both favorable and unfavorable seasons. A comparison between a conventional photothermogram and a newly formulated photohydrogram or photohygrogram demonstrates that even though sufficient heat is available, scarcity of water and thus scarcity of foliage should force the cricket to maintain diapause at intermediate temperature. The results suggested that high t 0, large body size, and multi-ennial lifecycle mutually affect each other and formulate a unique adaptation under such an extreme environment.  相似文献   

4.
This study characterizes the persistence of human norovirus in Eastern oysters (Crassostrea virginica) held at different seawater temperatures. Oysters were contaminated with human norovirus GI.1 (Norwalk strain 8FIIa) by exposing them to virus-contaminated water at 15 °C, and subsequently holding them at 7, 15, and 25 °C for up to 6 weeks. Viral RNA was extracted from oyster tissue and hemocytes and quantitated by RT-qPCR. Norovirus was detected in hemocytes and oysters held at 7 and 15 °C for 6 weeks and in hemocytes and oysters held at 25 °C for up to 2 and 4 weeks, respectively. Results confirm that NoV is quite persistent within oysters and demonstrate that cooler water temperatures extend norovirus clearance times. This study suggests a need for substantial relay times to remove norovirus from contaminated shellfish and suggests that regulatory authorities should consider the effects of water temperature after a suspected episodic norovirus-contamination event.  相似文献   

5.
以磷酸二氢钠和偏磷酸钠为磷标样,对加入不同盐试剂(灰化助剂)经不同温度(150℃~550℃)灼烧后磷的回收率进行了比较.所研究的灰化助剂除文献中报道过的MgSO4和Mg(NO3)2外,还对MgCl2等10余种盐试剂进行了实验.结果发现,磷酸二氢钠和偏磷酸钠加入MgSO4在常规的灼烧温度下灼烧,用0.2mol/L HCl于80℃浸提0.5h不能使磷全部回收,而MgCl2、MgA  相似文献   

6.
Considering high-moisture municipal solid waste (MSW) of China, a steam dried MSW gasification and melting process was proposed, the feasibility was tested, and the mass and energy balance was analyzed. Preliminary experiments were conducted using a fixed-bed drying apparatus, a 200 kg per day fluidized-bed gasifier, and a swirl melting furnace. Moisture percentage was reduced from 50% to 20% roughly when MSW was dried by slightly superheated steam of 150°C–350°C within 40 min. When the temperature was less than 250°C, no incondensable gas was produced during the drying process. The gasifier ran at 550°C–700°Cwith an air equivalence ratio (ER) of 0.2–0.4. The temperature of the swirl melting furnace reached about 1240°C when the gasification ER was 0.3 and the total ER was 1.1. At these conditions, the fly ash concentration in the flue gas was 1.7 g·(Nm3)−1, which meant over 95% fly ash was trapped in the furnace and discharged as slag. 85% of Ni and Cr were bound in the slag, as well as 60% of Cu. The mass and energy balance analysis indicates that the boiler heat efficiency of an industrial MSW incineration plant reaches 86.97% when MSW is dried by steam of 200°C. The boiler heat efficiency is sensitive to three important parameters, including the temperature of preheated MSW, the moisture percentage of dried MS Wand the fly ash percentage in the total ash.  相似文献   

7.
低温硝基苯降解菌的筛选及降解特性研究   总被引:16,自引:3,他引:13  
从被硝基苯污染的某河流底泥中分离到能在低温下生长并能以硝基苯为唯一碳源的7株细菌,其中菌株NB1在温度从2.5~35 ℃范围内时都可以生长并矿化20 mg/L的硝基苯,最适宜的生长温度为25 ℃左右;当培养温度为5 ℃时,该菌株在pH为6~9范围内可以快速降解20 mg/L硝基苯,偏碱性的条件比酸性条件更适合其生长;不超过100 mg/L的硝基苯可以被该细菌完全降解.通过生理生化反应特性、菌体形态以及16S rDNA序列测定结果,确定NB1为恶臭假单胞菌(Pseudomonas putida).不同温度条件,特别是低温下该菌株对硝基苯的快速降解特性为低温环境硝基苯污染的生物修复提供了可能.  相似文献   

8.
The waste electrical and electronic equipment (WEEE) directives are designed to deal with the rapidly increasing waste stream comprised of electrical and electronic equipment. Recycling electrical and electronic equipment reduces the quantity of waste going to final disposal. The demand for thin film transistor liquid crystal display (TFT-LCD) panels, commonly used in everyday electronic products, is increasing. Conventionally adopted treatments of TFT-LCD waste glass cannot meet WEEE directives. This study adopts the following operating conditions in fabricating glass–ceramics: sintering temperature of 800–950 °C; sintering time of 6 h; and, temperature increase rate of 5 °C/min. The glass–ceramic samples then underwent a series of tests, including the Vickers hardness, water absorption and porosity tests, to determine product quality. The Vickers hardness was 12.1 GPa when fired at 900 °C for 6 h, and density was 2.4 g/cm3 and water absorption was 0%. Thus, TFT-LCD waste glass can be regarded as a good glass–ceramic material.  相似文献   

9.
Unlike natural selection, phenotypic plasticity allows organisms to respond quickly to changing environmental conditions. However, plasticity may not always be adaptive. In insects, body size and other morphological measurements have been shown to decrease as temperature increases. This relationship may lead to a physiological conflict in ants, where larger body size and longer legs often confer better thermal resistance. Here, we tested the effect of developmental temperature (20, 24, 28 or 32 °C) on adult thermal resistance in the thermophilic ant species Aphaenogaster senilis. We found that no larval development occurred at 20 °C. However, at higher temperatures, developmental speed increased as expected and smaller adults were produced. In thermal resistance tests, we found that ants reared at 28 and 32 °C had half-lethal temperatures that were 2 °C higher than those of ants reared at 24 °C. Thus, although ants reared at higher temperatures were smaller in size, they were nonetheless more thermoresistant. These results show that A. senilis can exploit phenotypic plasticity to quickly adjust its thermal resistance to local conditions and that this process is independent of morphological adaptations. This mechanism may be particularly relevant given current rapid climate warming.  相似文献   

10.
There is a risk of virus transmission through contaminated pork, and many viruses are considered potential hazards for both humans and livestock. The risk of transmission may be elevated with importation/exportation of meat between countries globally. Survival of porcine reproductive and respiratory syndrome virus (PRRSV) in different pork products has not been studied. The present study evaluated PRRSV survival in four different products: fresh sausage, ham, bacon, and acidified sausage prepared with experimentally contaminated pork. These products were prepared according to standard methods used by the manufacturers of pork products, and then stored at room temperature, 4 °C and ?20 °C. PRRSV was detected only in fresh sausage for up to 15 days at 4 °C and for 30 days at ?20 °C. No PRRSV was detected at any temperature in any of the other three products. These preliminary data provide valuable information for the pork processing industry, as well as in planning for import/export of these products among different countries.  相似文献   

11.
Telomeric attrition has repeatedly been found to correlate with the ageing of organisms; however, recent research is increasingly showing that the determinants of attrition dynamics are not well understood. This study examined the relative telomere lengths in Eastern mosquitofish, Gambusia holbrooki, kept at different temperatures and at different ages. Newly born fry were randomly selected for one of four treatment groups: 20, 30, 20–30, and 30–20 °C, where the third and fourth treatment groups were gradually changed from their starting temperature to their final temperature between days 10 and 14. Telomere length was measured, and it was found that length decreased with age and that fish exposed to the 20 °C treatment had significantly shorter telomeres than those that received the 30–20 °C treatment. Telomeric attrition with age agrees with results previously found in studies of telomeres; however, the variation in attrition with temperature was not simply predictable and may be the synergistic effects of temperature and some other factor.  相似文献   

12.
To confirm whether the amplitude of diel temperature cycles causes a phase shift of adult eclosion rhythm of the onion fly, Delia antiqua, the peak time (Ø E) of adult eclosion was determined under various thermoperiods with a fixed temperature either in the warm or cool phase and temperature differences ranging from 1°C to 4°C between the two phases. Irrespective of the temperature level during the warm or cool phase, Ø E occurred earlier with decreasing amplitude of the temperature cycle. The results strongly support the previous conclusion of Tanaka and Watari (Naturwissenschaften 90:76–79, 2003) that D. antiqua responds to the amplitude of temperature cycle as a cue for the circadian adult eclosion timing. The phase advance was larger in thermoperiods with a fixed warm-phase temperature than in those with a fixed cool-phase temperature. This might be ascribed to the interaction between the amplitude and level of temperature in the thermoperiodic regimes.  相似文献   

13.
The petrology and geochemistry of a newly discovered suite of high-pressure garnet + clinopyroxene-bearing rocks from the Monotonous Series of the Moldanubian Zone of the Bohemian Massif, southwest Czech Republic have been investigated. Three types [common eclogites, quartz ± kyanite ± (clino)zoisite eclogites and garnet-hornblende-clinopyroxenites] are distinguished by petrography and geochemistry. All underwent a significant degree of partial breakdown under granulite and amphibolite facies conditions during exhumation. Important features include the growth of orthopyroxene in breakdown domains after garnet and omphacite and anorthite + spinel ± corundum ± exceedingly peraluminous sapphirine replacing kyanite. Garnet zoning and inclusion patterns support a prograde evolution from low pressures for at least some of the samples. The post-eclogite stage granulite facies overprint indicates that high temperatures prevailed during exhumation, but preservation of zoning in some garnets and the results of diffusion modelling suggest that this overprint took place over a very short time-scale. The geochemical and petrological results allow characteristic differences to be recognized between these eclogites and metabasites found in other tectonic units of South Bohemia and consequently the assigning of all high-pressure rocks to a single, now disrupted, tectonic unit is a gross simplification that seriously misrepresents the tectono-metamorphic history of the region.  相似文献   

14.
Investigation of the effects of pre-pressurization temperature on the high-pressure inactivation for single strains of aichivirus (AiV), coxsackievirus A9 (CAV9) and B5 (CBV5) viruses, as well as human parechovirus-1 (HPeV) was performed. For CAV9, an average 1.99 log10 greater inactivation was observed at 4 °C after a 400-MPa–5-min treatments compared to 20 °C treatments. For CBV5, an average of 2.54 log10 greater inactivation was noted after 600-MPa–10-min treatments at 4 °C in comparison to 20 °C treatments. In contrast, inactivation was reduced by an average of 1.59 log10 at 4 °C for HPeV. AiV was resistant to pressure treatments of 600 MPa for as long as 15 min at 4, 20, and 30 °C temperatures. Thus, different pre-pressurization temperatures result in different inactivation effects for picornaviruses.  相似文献   

15.
This study focuses on the ecological design between traditional Diyarbak?r houses and their physical environment (topography and climate) and structural environment (building form, spatial organization, material, landscape and planting, and technical infrastructure). The basic principle was to identify the criteria that would use natural energy sources and provide the most benefit to the inhabitants. The influence of different seasons on thermal perception was investigated. The average temperature differences between the outdoor and indoor environment of the houses were 7 °C in winter, 6 °C in summer and ±2 °C in spring and autumn. Consequently, this paper discusses ecological design solutions used in traditional houses and their applicability to modern buildings and recognizes that architecture should coexist and maintain harmony with nature.  相似文献   

16.
We present a methodology for using a domestic water use time series that were obtained from Yellow River Conservancy Commission, together with the climatic records from the National Climate Center of China to evaluate the effects of climate variability on water use in the Yellow River Basin. A suit of seven Global Circulation Models (GCMs) were adopted to anticipate future climate patterns in the Yellow River. The historical records showed evidences of rises in temperature and subsequent rises in domestic water demand in the basin. For Upstream of Longyangxia region, the impact was the least, with only 0.0021?×?108 m3 for a temperature increase of 1 °C; while for Longyangxia-Lanzhou region, domestic water use was found to increase to 0.18?×?108 m3 when temperature increases 1 °C. Downstream of Huayuankou was the region with the most changes in temperature that gave the highest increase of 1.95?×?108 m3 in domestic water demand for 1 °C of change of temperature. Downstream of Huayuankou was identified as the most vulnerable area, where domestic water demand increases nearly by 42.2 % with 1 °C increase of temperature. Judging from the trends of temperature range, we concluded that future temperature in Yellow River Basin has an increasing tendency. This could worsen the existing issues of domestic water demand and even more to trigger high competition among different water-using sectors.  相似文献   

17.
Microwave-hydrothermal treatment of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water with persulfate (S2O82−) has been found effective. However, applications of this process to effectively remediate PFOA pollution require a better understanding on free-radical scavenging reactions that also take place. The objectives of this study were to investigate the effects of pH (pH = 2.5, 6.6, 8.8, and 10.5), chloride concentrations (0.01–0.15 mol·L−1), and temperature (60°C, 90°C, and 130°C) on persulfate oxidation of PFOA under microwave irradiation. Maximum PFOA degradation occurred at pH 2.5, while little or no degradation at pH 10.5. Lowering system pH resulted in an increase in PFOA degradation rate. Both high pH and chloride concentrations would result in more scavenging of sulfate free radicals and slow down PFOA degradation. When chloride concentrations were less than 0.04 mol·L−1 at 90°C and 0.06 mol·L−1 at 60°C, presence of chloride ions had insignificant impacts on PFOA degradation. However, beyond these concentration levels, PFOA degradation rates reduced significantly with an increase in chloride concentrations, especially under the higher temperature.  相似文献   

18.
The distribution of metallic elements in a submerged membrane bioreactor(MBR) was revealed at different temperatures using inductively coupled plasma-optical emission spectrometry(ICP-OES), and the role of extracellular polymeric substances(EPS) was probed by integrating scanning electron microscopy(SEM) with confocal laser scanning microscopy(CLSM) over long-term operation. More metallic elements in the influent were captured by suspended sludge and built up in the fouling layer at lower temperature. The concentration of metallic elements in the effluent was 5.60 mg/L at 10°C operational temperature, far lower than that in the influent(51.35 mg/L). The total contents of metallic elements in suspended sludge and the membrane fouling layer increased to 40.20 and 52.19 mg/g at 10°C compared to 35.14 and 32.45 mg/g at 30°C, and were dominated by the organically bound fraction. The EPS contents in suspended sludge and membrane fouling layer sharply increased to 37.88 and 101.51 mg/g at 10°C, compared to 16.87 and 30.03 mg/g at 30°C. The increase in EPS content at lower temperature was responsible for the deposition of more metallic ions. The strong bridging between EPS and metallic elements at lower temperature enhanced the compactness of the fouling layer and further decreased membrane flux. This was helpful for understanding the mechanism of membrane fouling at different operational temperatures and the role of EPS, and also of significance for the design of cleaning strategies for fouled membranes after long-term operation.  相似文献   

19.
I studied the conditions controlling the timing of breeding migration of the Japanese mountain stream frog Rana sakuraii, an explosive breeder, over 9 years (1992, 1993 and 1999–2005). I analysed two factors: the daily cumulative temperature (DCT) during hibernation and the triggering temperature on the day of migration onset. Frogs hibernated in shallow running water in streams in December. A total of 53,155 breeding migrating adults were captured by traps. Every year, breeding migration was induced by a rise in daily maximum water temperature to about 5°C. However, its date was limited to 1 February at the earliest, and the onset needed a DCT (from 20 January, using 3°C as the threshold for daily effective temperature) of at least about 15°C. Earlier (e.g. in mid- or late January), even if the maximum temperature rose to 5–8°C, migration did not begin. Moreover, even in early February, if the maximum temperature rose to 5°C, if it had been too cold in January and the DCT was low, migration would not begin until mid- or late February. Thus, the earliest date of readiness for migration varied from 1 February to mid-February, depending on the winter DCT. Logistic regression analyses showed that both factors, the DCT and the daily temperature, were significant. I propose that in temperate-zone amphibian explosive breeders, both the passing of an essential number of days and an essential DCT during hibernation are prerequisites for the onset of breeding migration before the daily temperature rises to the threshold.  相似文献   

20.
The resistance of the grain mite Acarus siro to unfavourable physical conditions was studied to determine how long some members of a population might survive so that development and increase could continue if conditions became favourable. Preliminary experiments showed that: (i) the eggs formed the most resistant stage, both to extreme temperatures and to desiccation; (ii) the most resistant eggs were those in an early stage of development, and that resistance declined with age; and (iii) environmental conditions prior to oviposition influenced resistance, resistance being greater in eggs from populations reared at near threshold conditions than in those reared at ecologically more favourable temperatures and humidities.Experiments with eggs exposed to lethal high and low temperatures and to both favourable and desiccating humidities show that above 30°C and below 0°C, relative humidity ceased to affect survival, the eggs being killed by heat or cold before the effects of desiccation became important. Eggs were fairly susceptible to high temperatures; none survived longer than 10 h at 35°C or 35 min at 40°C. They showed greater tolerance to low temperatures, surviving up to a maximum of 12–14 days at ?10°C and 24–26 days at ?5°C. At 0°C, the maximum survival period varied from 80 days at 20% RH to 180 days at 90% RH. For eggs exposed at temperatures within the developmental temperature range to relative humidities from 20 to 50%, survival appeared to be directly related to humidity and inversely to temperature, maximum survival periods ranging from 20 days (20% RH) to 45 days (50% RH) at 5°C, and from 1 day (20% RH) to 3 days (50% RH) at 30°C.  相似文献   

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