Sex allocation in a monomorphic seabird with a single-egg clutch: test of the environment, mate quality, and female condition hypotheses

Sex allocation theory posits that mothers should preferentially invest in sons when environmental conditions are favorable for breeding, their mates are of high quality, or they are in good body condition. We tested these three hypotheses in rhinoceros auklets (Cerorhinca monocerata), monomorphic seabirds that lay a single-egg clutch, in 2 years that differed in environmental conditions for breeding. Results supported the environment and mate quality hypotheses, but these effects were interactive: offspring sex was independent of paternal traits in the poor year for breeding, while females mated to larger and more ornamented males reared more sons in the better year. Conversely, offspring sex was unrelated to female condition, as indexed by hatching date. We propose that good rearing conditions enable females to rear sons possessing the desirable phenotypic attributes of their mates. Results also supported two critical assumptions of sex allocation theory: (1) dimorphism in offspring condition at independence: daughters fledged with higher baseline levels of corticosterone than sons and (2) differential costs of rearing sons versus daughters: mothers rearing sons when environmental conditions were poor completed parental care in poorer condition than mothers rearing daughters in the same year and mothers rearing either sex when conditions were better. These novel results may help to explain the disparate results of previous studies of avian sex allocation.     

Resource defense polygyny shifts to female defense polygyny over the course of the reproductive season of a Neotropical harvestman

Although studies classify the polygynous mating system of a given species into female defense polygyny (FDP) or resource defense polygyny (RDP), the boundary between these two categories is often slight. Males of some species may even shift between these two types of polygyny in response to temporal variation in social and environmental conditions. Here, we examine the mating system of the Neotropical harvestman Acutisoma proximum and, in order to assess if mate acquisition in males corresponds to FDP or RDP, we tested four contrasting predictions derived from the mating system theory. At the beginning of the reproductive season, males fight with other males for the possession of territories on the vegetation where females will later oviposit, as expected in RDP. Females present a marked preference for specific host plant species, and males establish their territories in areas where these host plants are specially abundant, which is also expected in RDP. Later in the reproductive season, males reduce their patrolling activity and focus on defending individual females that are ovipositing inside their territories, as what occurs in FDP. This is the first described case of an arachnid that exhibits a shift in mating system over the reproductive season, revealing that we should be cautious when defining the mating system of a species based on few observations concentrated in a brief period. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

固体废物的资源化和综合利用技术

固体废物对环境的污染已越来越多地引起世人关注,治理固体废物的根本出路除减少产生量外,资源化与综合利用是最积极的措施。文中简要的介绍了固体废物资源化的有关技术和我国开展固体废物综合利用的措施及手段。      

石油产品装卸过程中的油气回收技术

介绍了石油产品装卸过程产生的油气污染及其治理方法、工艺过程与技术特点。结合中国石化股份有限公司长岭分公司石油产品装卸过程产生的油气污染情况,对油气回收方案的选择、回收工艺及油品回收情况与经济效益进行了论述。     

硫磺回收装置扩能改造及效果分析

介绍了回收酸性气体生产硫磺的工艺原理与工艺流程,论述了影响硫磺回收装置生产能力的诸多因素与扩能改造的情况。扩能改造后,该装置的酸性气体处理量平均为976m^3／h,瞬时处理量可达1200m^3／h,硫磺的生产能力从4450t／a提高到7500t／a,生产能力提高了68．5％,装置总硫回收率达到93．5％。     

建设资源循环型城市是实现可持续发展战略的重要途径

从目前严峻的资源与生态环境形势看 ,要实现全面建设小康社会的目标和满足新型工业化道路的标准要求 ,实现经济发展与环境保护双赢 ,实现经济增长方式从粗放型向集约型转变 ,实现经济结构战略性调整和产业结构升级 ,发展循环经济是城市未来社会经济可持续发展的最佳模式选择     

扩展流好气滤池反冲洗机理与试验分析

采用对照研究的方法对扩展流好气滤池反冲洗方式进行选择。结果表明 ,脉冲反冲洗方式以其高效、低耗的特点明显优于气水连续反冲洗方式 ,并遵循好气滤池反冲洗的要求。扩展流好气滤池脉冲反冲洗的最佳运行参数确定为 :气冲强度 8～ 10 L/( s·m2 ) ;水冲强度 2～ 4L/( s·m2 ) ;反冲时间 5 min。     

Natural and Anthropogenic Changes in The Chemistry of Six UK Mountain Lakes, 1988 to 2000

Trends have been analysed for 12 years ofchemical data from six mountain lakes in the UK AcidWaters Monitoring Network (AWMN). With minimal localanthropogenic impacts, these sites offer the bestavailable opportunity for clear identification of surfacewater chemical response to external factors, whethernatural or anthropogenic. Results indicate that naturalclimatic variations have had a major impact on lakechemistry, through fluctuations in (i) intensity ofstorms, which cause dilution of weathering-derived basecations, and/or displacement of hydrogen and aluminiumions on soil exchange sites by deposited marine basecations; and (ii) winter temperature, which is thought tobe inversely related to spring nitrate (NO₃) maxima.Both climatic factors can be linked to the North AtlanticOscillation. For the first decade of AWMN monitoringthese natural `confounding factors' to a significantextent obscured any recovery from acidification due todeclining anthropogenic sulphur deposition. However, theadditional data presented here provide strengtheningevidence for chemical recovery at a number of sites, atwhich decreases in sulphate (SO₄), acidity andlabile aluminium can now be identified. It is believedthat changes at these sensitive mountain lake sites mayherald more widespread recovery in UK surface waters aspollutant emissions decline further. However, largeincreases in dissolved organic carbon, and hence inorganic acidity, may have partially offset reductions inmineral acidity. The cause of these increases remainsuncertain, but may be linked to climatic change.     

资源型城市典型矿产资源物质流分析——以安徽省铜陵市为例

通过对铜陵市支柱资源铜矿的铜元素物质流进行实证分析,得出铜陵市铜矿资源的综合利用率和循环率都达到了较高水平,但存在自给率偏低的限制因素,需要采取综合措施予以改善。     

Valorization of sodium sulfate waste to potassium sulfate fertilizer: experimental studies,process modeling,and optimization

ABSTRACT

Sodium sulfate is a common low-value industrial by-product but can be managed using the Glaserite process to convert it into high-value potassium sulfate. The aim of the study is to investigate the potential for implementing this process in an industrial application. Experimental studies were completed to determine the yield and purity of both glaserite and potassium sulfate. Process simulation using SysCAD was utilized to optimize a two-stage glaserite process to produce potassium sulfate. Comparison of experimental and simulated data was made to validate the simulator’s results, finding the AAD in solid and liquid phase for glaserite production to be 6.9% and 5.7%, respectively, and for potassium sulfate to be 5.7% and 2.3%, respectively. For a process treating seven MT/hr of Na₂SO₄, a KCl feed strategy of 3.0 MT/hr to the glaserite reactor and 4.5 MT/hr to the K₂SO₄ reactor was found to maximize yield and minimize water demand. It was also found that ambient temperatures were preferred for the K₂SO₄ reactor and that K₂SO₄ yield suffered significantly under certain conditions when the glaserite reactor operated at 50°C or above.