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281.
Behavioral experiments have shown that male copepods of the species Tigriopus japonicus (Nori) can distinguish species, sex, and developmental stage of potential mates using contact chemoreception. Lectin-binding
patterns on the body surface of females have indicated that surface-bound glycoproteins may be important signals in mate choice.
In the present study, the proteolytic enzyme trypsin was used to cleave surface proteins from females, reducing their attractiveness
to males. The protein fragments released were used to make monoclonal antibodies. Three levels of screening were used to identify
monoclonal antibodies that recognized proteins involved in mate recognition. One monoclonal antibody bound to the terminal
urosome and lateral prosome of CV females, and its binding significantly decreased female attractiveness to males. Western
blotting showed that this antibody bound the trypsin-cleaved fragment and proteins of homogenized CV females and virgin adult
females, but did not bind proteins of homogenized males, CIII females, or females of T. californicus or T. fulvus. This antibody recognized proteins on the surface of females that may enable males to discriminate conspecifics, sex, and
age. It is likely that this molecule has a central role in the evolution of reproductive isolation in this group.
Received: 22 July 1999 / Accepted: 21 March 2000 相似文献
282.
Keogh Diane U. Kelly Joe Mengersen Kerrie Jayaratne Rohan Ferreira Luis Morawska Lidia 《Environmental science and pollution research international》2010,17(3):724-739
Background, aim and scope
Urban motor vehicle fleets are a major source of particulate matter pollution, especially of ultrafine particles (diameters < 0.1 μm), and exposure to particulate matter has known serious health effects. A considerable body of literature is available on vehicle particle emission factors derived using a wide range of different measurement methods for different particle sizes, conducted in different parts of the world. Therefore, the choice as to which are the most suitable particle emission factors to use in transport modelling and health impact assessments presented as a very difficult task. The aim of this study was to derive a comprehensive set of tailpipe particle emission factors for different vehicle and road type combinations, covering the full size range of particles emitted, which are suitable for modelling urban fleet emissions. 相似文献283.
Steven Brooks Winston Luke Mark Cohen Paul Kelly Barry Lefer Bernhard Rappenglück 《Atmospheric environment (Oxford, England : 1994)》2010,44(33):4045-4055
Atmospheric mercury speciation was monitored within Houston, Texas, USA, August 6–October 14, 2006 as part of the TexAQS Radical and Aerosol Measurement Program (TRAMP). On average, all mercury levels were significantly elevated compared to a rural Gulf of Mexico coastal site. Concentrations varied from very clean to very dirty. Multi-day periods of stagnant or low-wind conditions brought elevated concentrations of all mercury species, whereas multi-day periods of strong winds, particularly southerly winds off the Gulf of Mexico, brought very low values of mercury species. Over the entire mercury measurement period, the daily averages of mercury species showed distinct and consistent relationships with the average planetary boundary layer dynamics, with gaseous elemental and particulate-bound mercury near-surface concentrations enhanced by a shallow nocturnal boundary layer, and reactive gaseous mercury concentration enhanced by midday convective boundary layer air entrainment transporting air aloft to the surface. Mercury concentrations were not significantly correlated with known products of combustion, likely indicating non-combustion mercury sources from the Houston area petrochemical complexes. On the morning of August 31, 2006 an observed emission event at a refinery complex on the Houston Ship Channel resulted in extremely high concentrations of aerosol mass and particulate-bound mercury at the TRAMP measurement site 20 km downwind. 相似文献
284.
Kelly KE Jaramillo IC Quintero-Núñez M Wagner DA Collins K Meuzelaar HL Lighty JS 《Journal of the Air & Waste Management Association (1995)》2010,60(12):1476-1486
The U.S. Environmental Protection Agency (EPA) currently classifies Imperial County, CA, as a nonattainment area for PM10 (particulate matter [PM] < or = 10 microm in diameter), and this region suffers from high rates of chronic bronchitis and childhood asthma. Although high annual and daily average PM levels can have negative health and economic effects, recent studies have identified an association between adverse health effects and short-term PM spikes of tens of micrograms per cubic meter. This study identified PM episodes in Calexico/Mexicali that involve PM concentration spikes with concentrations up to 10 times greater than those reported to cause adverse health effects. These episodes appear to be relatively common during the winter months, are associated with wind speeds below 2 m/sec and stable boundary level heights below 500 m, and can comprise a large portion of the 24-hr PM levels. The organic composition of the PM10 samples collected during the low-wind/ high-PM episodes differed from that collected at other times. However, a preliminary source attribution identified only one significant difference between the source classes: agricultural burning accounted for 6.7% of organic-fraction PM10 for low-wind/high-PM episodes versus 0.25% at other times. This preliminary source attribution also revealed that motor vehicles were the most important relative contributor to organic PM10. 相似文献
285.
中国北方地区水体中四环素族抗生素残留现状分析 总被引:16,自引:3,他引:13
为了更好了解北方市政污水等水体中四环素族抗生素残留现状,采用固相萃取方法对中国北方地区市政污水样品进行富集和净化,以高效液相色谱-串联质谱法分析样品中四环素族抗生素残留量。在调查的13个污水样品中四环素族抗生素普遍检出,且浓度分别达到四环素1114.27ng/L、土霉素2175.65ng/L、金霉素149.09ng/L和强力霉素187.45ng/L。结果表明,在我国近岸污水排放中依然有大量四环素类抗生素存在,应加强对近岸海洋环境中抗生素残留的监测与管理。 相似文献
286.
Orchid-fungus fidelity: a marriage meant to last? 总被引:1,自引:0,他引:1
The characteristics of plant-mycorrhizae associations are known to vary in both time and space, but the ecological consequences of variation in the dynamics of plant-fungus interactions are poorly understood. For example, do plants associate with single fungi or multiple fungi simultaneously, and do the associations persist through a plant's lifetime or do plants support a succession of different fungi? We investigated these and other questions related to plant-fungus interactions in Goodyera pubescens, an evergreen terrestrial orchid of the eastern United States, that interacts with closely related fungi in the genus Tulasnella. Unlike the mycorrhizal associations of other plants, orchid-mycorrhizal associations only benefit the orchid, based on current evidence. Many terrestrial orchids have been found to associate with specific groups of fungi. This characteristic could potentially limit orchids to relatively narrow ranges of environmental conditions and may be a contributing factor in the decline of many orchids in the face of changing environmental conditions. We found that G. pubescens protocorms (developing embryos prior to leaf production) and adults associated with only one fungal individual at a time. The orchid-fungus association persists for years, but during a drought period that was associated with the death of many plants, surviving plants were able to switch to new fungal individuals. These results suggest that G. pubescens interacts with the same fungal partner during periods of modest environmental variation but is able to switch to a different fungal partner. We hypothesize that the ability to switch fungi allows G. pubescens to survive more extreme environmental perturbations. However, laboratory experiments suggest that switching fungi has potential costs, as it increases the risk of mortality, especially for smaller individuals. Our findings indicate that it is unlikely that switching fungi is a common way to improve tolerance of less severe environmental fluctuations and disturbances. These findings may have important implications for plant responses to severe climatic events or to more gradual environmental changes such as global warming. 相似文献
287.
Kelly K Wagner D Lighty J Quintero Núñez M Vazquez FA Collins K Barud-Zubillaga A 《Journal of the Air & Waste Management Association (1995)》2006,56(3):285-293
The investigators developed a system to measure black carbon (BC) and particle-bound polycyclic aromatic hydrocarbon (PAH) emission factors during roadside sampling in four cities along the United States-Mexico border, Calexico/Mexicali and El Paso/Juarez. The measurement system included a photoacoustic analyzer for BC, a photoelectric aerosol sensor for particle-bound PAHs, and a carbon dioxide (CO2) analyzer. When a vehicle with measurable emissions passed the system probe, corresponding BC, PAH, and CO2 peaks were evident, and a fuel-based emission factor was estimated. A picture of each vehicle was also recorded with a digital camera. The advantage of this system, compared with other roadside methods, is the direct measurement of particulate matter components and limited interference from roadside dust. The study revealed some interesting trends: Mexican buses and all medium-duty trucks were more frequently identified as high emitters of BC and PAH than heavy-duty trucks or passenger vehicles. In addition, because of the high daily mileage of buses, they are good candidates for additional study. Mexican trucks and buses had higher average emission factors compared with U.S. trucks and buses, but the differences were not statistically significant. Few passenger vehicles had measurable BC and PAH emissions, although the highest emission factor came from an older model passenger vehicle licensed in Baja California. 相似文献
288.
Field-based cultivation of Kappaphycus and Eucheuma seaweeds is widespread across the tropics and is largely done to extract the polysaccharide carrageenan, which is used in commercial applications. Although such seaweed farming has been cited as a sustainable alternative livelihood to destructive fishing, there has not been a comprehensive review of its environmental impacts to assess its potential conservation benefit. We reviewed the peer-reviewed and industry gray literature to determine what is known about seaweed farming techniques and their impacts on local ecosystems, organisms, and ecosystem services. We identified 43 tropical or subtropical countries that are currently cultivating or have cultivated carrageenophytes. Ecosystem impacts of seaweed farming were measured directly in 33 publications with variable results. Placement of seaweed farms above seagrass beds led to reduced productivity and shoot density in 5 studies and reduced or altered meiofaunal abundance and diversity in 6 studies. On coral reefs, overgrowth of corals by farmed seaweed species was documented in 8 cases. Two studies showed changes to herbivorous fish communities in adjacent areas because seaweed farms changed the environment, whereas in 2 studies measures of overall abundance or diversity did not change. The impacts of seaweed farming may not be as destructive as some other human activities, but they should still be considered when establishing new farms or managing existing farm sites. Our findings are consistent with suggestions to mitigate impact on local ecosystems by shifting seaweed farms to deeper, sandy-bottom areas. However, some of these changes may adversely affect farmers and associated communities. 相似文献
289.
Luke T. Kelly Andrew F. Bennett Michael F. Clarke Michael A. McCarthy 《Conservation biology》2015,29(2):473-481
Fire is used as a management tool for biodiversity conservation worldwide. A common objective is to avoid population extinctions due to inappropriate fire regimes. However, in many ecosystems, it is unclear what mix of fire histories will achieve this goal. We determined the optimal fire history of a given area for biological conservation with a method that links tools from 3 fields of research: species distribution modeling, composite indices of biodiversity, and decision science. We based our case study on extensive field surveys of birds, reptiles, and mammals in fire‐prone semi‐arid Australia. First, we developed statistical models of species’ responses to fire history. Second, we determined the optimal allocation of successional states in a given area, based on the geometric mean of species relative abundance. Finally, we showed how conservation targets based on this index can be incorporated into a decision‐making framework for fire management. Pyrodiversity per se did not necessarily promote vertebrate biodiversity. Maximizing pyrodiversity by having an even allocation of successional states did not maximize the geometric mean abundance of bird species. Older vegetation was disproportionately important for the conservation of birds, reptiles, and small mammals. Because our method defines fire management objectives based on the habitat requirements of multiple species in the community, it could be used widely to maximize biodiversity in fire‐prone ecosystems. Historiales de Incendios Óptimos para la Conservación de la Biodiversidad 相似文献
290.
The complex relationship between personal sense of connection to animals and self‐reported proenvironmental behaviors by zoo visitors
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Alejandro Grajal Jerry F. Luebke Lisa‐Anne DeGregoria Kelly Jennifer Matiasek Susan Clayton Bryan T. Karazsia Carol D. Saunders Susan R. Goldman Michael E. Mann Ricardo Stanoss 《Conservation biology》2017,31(2):322-330
The global biodiversity crisis requires an engaged citizenry that provides collective support for public policies and recognizes the consequences of personal consumption decisions. Understanding the factors that affect personal engagement in proenvironmental behaviors is essential for the development of actionable conservation solutions. Zoos and aquariums may be some of the only places where many people can explore their relations with wild animals and proenvironmental behaviors. Using a moderated‐mediation analysis of a survey of U.S. zoo and aquarium visitors (n = 3588), we explored the relationship between the sense of connection to animals and self‐reported engagement in proenvironmental behaviors related to climate change and how this relationship is affected by certainty that climate change is happening, level of concern about climate change, and perceptions of effectiveness in personally addressing climate change. We found a significant, directional relationship between sense of connection to animals and self‐reported proenvironmental behaviors. Political inclination within the conservative to liberal spectrum did not affect the relationship. We conclude that a personal sense of connection to animals may provide a foundation for educational and communication strategies to enhance involvement in proenvironmental actions. 相似文献