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71.
The pattern of settlement over time of three broadcast spawning coral species (Cyphastrea serailia, Acanthastrea lordhowensis, and Goniastrea australensis) from the Solitary Islands (30°00′S; 153°20′E) was studied in 1995 and 1996 in order to determine the maximum length of time
these larvae could remain in the water column and still retain the ability to settle and metamorphose. Larvae were maintained
in aquaria and the number which had settled on biologically-conditioned tile pairs was monitored every 5 to 10 d. While the
majority of larvae settled quickly after becoming competent, some larvae survived and settled for extended periods after spawning.
Competency periods ranged from 26 d for C. serailia to 56 d for G. australensis and 78 d for A. lordhowensis. These data greatly extend the known competency periods for larvae of broadcast-spawning corals and indicate the potential
for transport of broadcast-spawned coral larvae over large distances. Medium to long-distance larval dispersal of the species
studied provides a mechanism for their widespread distribution in subtropical regions, on reefs which are often widely spaced
and relatively isolated.
Received: 27 May 1997 / Accepted: 27 November 1997 相似文献
72.
73.
José Carlos de Moura Xavier Irany de Andrade Azevedo Wilson Cabral de Sousa Junior Augusto Nishikawa 《Environmental monitoring and assessment》2013,185(2):1463-1471
Atmospheric pollutant monitoring constitutes a primordial activity in public policies concerning air quality. In São Paulo State, Brazil, the São Paulo State Environment Company (CETESB) maintains an automatic network which continuously monitors CO, SO2, NO x , O3, and particulate matter concentrations in the air. The monitoring process accuracy is a fundamental condition for the actions to be taken by CETESB. As one of the support systems, a preventive maintenance program for the different analyzers used is part of the data quality strategy. Knowledge of the behavior of analyzer failure times could help optimize the program. To achieve this goal, the failure times of an ozone analyzer—considered a repairable system—were modeled by means of the nonhomogeneous Poisson process. The rate of occurrence of failures (ROCOF) was estimated for the intervals 0–70,800 h and 0–88,320 h, in which six and seven failures were observed, respectively. The results showed that the ROCOF estimate is influenced by the choice of the observation period, t 0?=?70,800 h and t 7?=?88,320 h in the cases analyzed. Identification of preventive maintenance actions, mainly when parts replacement occurs in the last interval of observation, is highlighted, justifying the alteration in the behavior of the inter-arrival times. The performance of a follow-up on each analyzer is recommended in order to record the impact of the performed preventive maintenance program on the enhancement of its useful life. 相似文献
74.
75.
Mathematical Modeling of Column and Field Dense Nonaqueous Phase Liquid Tracer Tests 总被引:2,自引:0,他引:2
David J. Wilson Ronald A. Burt Douglas S. Hodge 《Environmental monitoring and assessment》2000,60(2):181-216
Mathematical models for the simulation of dense nonaqueous phase liquid tracer tests (DTTs) in laboratory columns and in the field are developed and examined. The DTT technique is a means of estimating the quantity of dense nonaqueous phase liquid (DNAPL) in a domain of interest in an aquifer. The two-dimensional field DTT model uses the Method of Principal Directions and an asymmetrical upwind algorithm for describing advective transport. Both models include diffusion transport of tracer into and from low-permeability porous structures such as clay lenses, as well as the mass transport kinetics of partitioning tracer to and from the DNAPL droplets. The dependence of the effluent tracer concentration curves on the parameters of the models is explored, and conclusions are drawn regarding the applicability of, and several possible problems with, the DTT technique. Model results indicate that the DTT performs well at locating distributed droplets of DNAPL, but is unlikely to be useful in the assessment of pooled DNAPL. 相似文献
76.
77.
The use of multistage, dry, fluidized beds of continuously recycled, coal-based activated carbon appears technically and economically attractive for both adsorption of stack gas So2 and sequential conversion to elemental sulfur. Conceptual design details and economic factors are discussed for the treatment of power plant or oil refinery SO2 effluents with by-product sulfur recovery. 相似文献
78.
Don H. Kampbell John T. Wilson Harvey W. Read Thomas T. Stocksdale 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1236-1240
Soil removal of propane, isobutane and n-butane from a waste air stream was evaluated in the laboratory and in a prototype soil bioreactor. Laboratory investigations indicated first-order kinetics and the potential to degrade light aliphatic hydrocarbons and trichlorethylene, a compound ordinarily resistant to aerobic biological treatment. The predicted behavior of the bioreactor, based on laboratory studies, agreed closely with the actual behavior of the Reid system. The prototype bioreactor reduced the hydrocarbon concentrations in the air by at least 90percent with a residence time of 15 minutes and a pressure drop of 85 cm of water. The bioreactor functioned well through a range of temperatures, 12°C to 24°C. 相似文献
79.
Speed-accuracy tradeoffs are a common feature of decision-making processes, both in individual animals and in groups of animals
working together to reach a single collective decision. Individual organisms display consistent differences in their “impulsivity,”
and vary in their tendency to make rapid, impulsive choices as opposed to slower, more accurate decisions. However, we do
not yet know whether groups of animals consistently differ in their tendency to prioritize decision speed over accuracy. We
challenged 17 swarms of honey bees (Apis mellifera) to simultaneously choose a new nest site in each of three locations, and measured their decision speeds in each trial. We
found that swarms displayed consistent personality differences in the number of waggle dances and shaking signals they performed
and in how actively they scouted for new nest sites. However, swarms did not consistently differ in how long they took to
choose a nest site. We suggest that house-hunting A. mellifera swarms may place an especially high emphasis on decision accuracy when choosing a nest site, and that chance events—such
as the time when each swarm discovers a sufficiently high-quality nest site—may consequently play a greater role in determining
a swarm’s decision speed than intrinsic characteristics such as a swarm’s “impulsivity.” 相似文献
80.
Iqbal Farheena Wilson Robyn Ayub Qasim Song Beng Kah Krzeminska-Ahmedzai Urszula Talei Amin Hermawan Andreas Aditya Rahman Sadequr 《Environmental science and pollution research international》2023,30(13):35715-35726
Environmental Science and Pollution Research - Urban-dwelling birds can be useful biomonitors to assess the impact of the urbanisation on both public and wildlife health. Widely distributed urban... 相似文献