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1.
Temperature and metabolic rate in sedentary fish from the Antarctic,North Sea and Indo-West Pacific Ocean 总被引:2,自引:0,他引:2
Resting metabolic rate
was measured in demersal stages of the teleostNotothenia neglecta Nybelin from the South Orkney Islands, Antarctica, from 1985 to 1987. The relationship between
and body mass (Mb) conformed to the general relationship
, wherea is a proportionality constant andb is the scaling exponent.
(mg O2 h–1) was found to scale toMb
(0.82±0.011) in the summer (November to April, 1.6 to 1 850 g,n=56) and toMb
(0.76±0.013) in the winter (May to October, 0.9 to 1 850 g,n=57) (values ofb are means ± SD). Although the scaling exponents were significantly different (P<0.01),
was similar in the juvenile stages of summer- and winter-caught fish matched for body mass. The effects of activity on oxygen consumption was studied using a Brett respirometer. Adult stages had a factorial aerobic scope for activity
of 5.7, which is similar to that reported for demersal fish from temperate latitudes. The effects of temperature on resting metabolism was investigated in fish with similar sedentary lifestyles from the North Sea (Agonus cataphractus andMyoxocephalus scorpius) and the Indo-West Pacific (Paracirrhites forsteri, P. arcatus, Neocirrhites armatus andExallias brevis). Extrapolated values of
for the tropical species approached zero at 5 to 10°C. For a standard 50 g fish,
for the tropical species at 25°C was in the range 3.4 to 4.4 mg O2 h–1, compared with 1.3 mg O2 h–1 forNotothenia neglecta at its acclimation temperature. Thus, the maximum metabolic rate of sedentary tropical species at 24°C is likely to be 2 to 4 times higher than inN. neglecta at 0°C. This suggests that the energy available for sustained activity
is significantly lower in cold- than in warm-water fish. 相似文献
2.
C. Clark K. F. Kelly N. Smith N. Fairweather T. Brown A. Johnston N. E. Haites 《黑龙江环境通报》1991,11(7):467-470
The polymerase chain reaction has been used to detect an abundant class of short repeat DNA families of the form (dC-dA)n.(dG-dT)n, known as microsatellites. These units are found throughout the human genome and have been characterized for several loci including APOC2 on chromosome 19ql2-ql3.2. The locus APOC2 is linked to the gene for dystrophia myotonica and a microsatellite within this locus was used to derive polymorphisms in a family to predict the inheritance of the disease. Chorionic villus sampling (CVS) was performed at 151/2 weeks' gestation. Following DNA extraction from the CVS material and parental blood samples, microsatellite analysis was carried out by the polymerase chain reaction. 相似文献
3.
Laboratory column experiments run for up to 13 days compared air sparging of groundwater contaminated by dissolved petroleum hydrocarbons in sterile and non-sterile aquifer sediments as well as uncontaminated sediments and groundwater. Loss of dissolved BTEX compounds in the contaminated columns was very rapid, occurring through volatilisation. The majority of the dissolved total organic carbon (TOC) persisted for much longer periods however. A direct comparison between losses from sterile and non-sterile columns suggested a negligible contribution of biodegradation to the removal of TOC. This was difficult to confirm through examination of O2 utilisation because oxidation of a small amount of reduced sulphur in the aquifer materials was the dominant sink for O2. Despite this, it was possible to conclude that less than 22% of the removal of TOC was through biodegradation during the first three days of air sparging. 相似文献
4.
John Doherty John M. Johnston 《Journal of the American Water Resources Association》2003,39(2):251-265
ABSTRACT: The use of a fitted parameter watershed model to address water quantity and quality management issues requires that it be calibrated under a wide range of hydrologic conditions. However, rarely does model calibration result in a unique parameter set. Parameter nonuniqueness can lead to predictive nonuniqueness. The extent of model predictive uncertainty should be investigated if management decisions are to be based on model projections. Using models built for four neighboring watersheds in the Neuse River Basin of North Carolina, the application of the automated parameter optimization software PEST in conjunction with the Hydrologic Simulation Program Fortran (HSPF) is demonstrated. Parameter nonuniqueness is illustrated, and a method is presented for calculating many different sets of parameters, all of which acceptably calibrate a watershed model. A regularization methodology is discussed in which models for similar watersheds can be calibrated simultaneously. Using this method, parameter differences between watershed models can be minimized while maintaining fit between model outputs and field observations. In recognition of the fact that parameter nonuniqueness and predictive uncertainty are inherent to the modeling process, PEST's nonlinear predictive analysis functionality is then used to explore the extent of model predictive uncertainty. 相似文献
5.
The oxidation and acidification of sulfidic soil materials results in the re-partitioning of metals, generally to more mobile forms. In this study, we examine the partitioning of Fe, Cr, Cu, Mn, Ni and Zn in the acidified surface soil (0-0.1 m) and the unoxidised sub-soil materials (1.3-1.5 m) of an acid sulfate soil landscape. Metal partitioning at this acidic site was then compared to an adjacent site that was previously acidified, but has since been remediated by tidal re-inundation. Differences in metal partitioning were determined using an optimised six-step sequential extraction procedure which targets the “labile”, “acid-soluble”, “organic”, “crystalline oxide”, “pyritic” and “residual” fractions. The surficial soil materials of the acidic site had experienced considerable losses of Cr, Cu, Mn and Ni compared to the underlying parent material due to oxidation and acidification, yet only minor losses of Fe and Zn. In general, the metals most depleted from the acidified surface soil materials exhibited the greatest sequestration in the surface soil materials of the tidally remediated site. An exception to this was iron, which accumulated to highly elevated concentrations in the surficial soil materials of the tidally remediated site. The “acid-soluble”, “organic” and “pyritic” fractions displayed the greatest increase in metals following tidal remediation. This study demonstrates that prolonged tidal re-inundation of severely acidified acid sulfate soil landscapes leads to the immobilisation of trace metals through the surficial accumulation of iron oxides, organic material and pyrite. 相似文献
6.
This study examines: (1) the impact of two methods of giving screening results on health behaviour and beliefs, evaluated in a randomized controlled trial. (2) The association between uptake of screening and health risk behaviours and beliefs. Two methods of feedback of screening results were given: simple informational feedback, and more extensive feedback, including target-setting and a written contract. At six month follow-up, those who received simple informational feedback had lost less weight and had increased their exercise less than those who received more extensive feedback. Attenders believed more strongly in the relationship between lifestyle and health, perceived themselves as less healthy than others and scored higher on the GHQ than staff who did not attend for screening. These results suggest that belief in the effectiveness of lifestyle change in promoting health, and anxiety about health, can influence uptake of screening. Second, the method of presenting screening results can influence the impact of screening on subsequent behaviour change. 相似文献
7.
Rosanna L. Mattingly Edwin E. Herricks Douglas M. Johnston 《Environmental management》1993,17(6):781-795
The environmental impact of loss of natural stream and riparian habitat is of concern throughout the United States and Europe.
Environmental impacts related to such activities as channelization of and levee construction along streams and rivers are
particularly apparent in the Midwestern United States. The objective of the research presented here was to delineate the extent,
relative degree of impact, and implications for management of channelization and levee construction along watercourses located
in the state of Illinois. According to records maintained through the Illinois Streams Information System data base (Illinois
Department of Conservation), nearly 25% of surface water resources in the state have been modified directly by channelization
and/or levee construction. Reviews of agency records, elaboration of case histories, interviews with agency personnel, and
inspections of impacted sites indicated that these alterations have occurred without the benefit of effective mitigation.
Although permit records may provide suggestions for mitigation to be incorporated in the design of a particular project, permits
issued generally do not require even minimal instream habitat and bank stabilization efforts in conjunction with channel alteration.
Information derived from policy and case study analyses suggests that institutional constraints, rather than lack of particular
understanding about mitigation, provide major barriers to protecting the state's surface water resources in terms of regulatory
review, policy interpretation and implementation, and project evaluation. Recommendations for environmental management efforts
regarding these and similar channel alterations are elaborated from these findings. 相似文献
8.
There are profound differences in the ways that the sponge Callyspongia diffusa reacts to self versus non-self tissue contact. Syngeneic or isogeneic contacts result in rapid tissue fusion and persistent maintenance of normal sponge structure. However, allogeneic contacts result in immune-type rejection reactions leading to tissue death at the interface. Using grafted sponge tissues, both types of response were subject to fine-structural analysis by scanning electron microscopy. Isografts showed no overt cellular reactions other than compatible fusion, whereas sponge tissues at allograft interfaces showed incompatibility reactions. The major steps in the histopathologic sequence of events in allograft reactions may be summarized as follows: (1) immediate allorecognition occurs accompanied by microscopic cellular rearrangements; (2) macroscopic tissue bridges form across the graft interface; (3) massive cellular infiltration towards graft sites, with cells often passing into a graft partner through the tissue bridges; (4) cellular hyperplasia and then cell death occurs at the interface; and (5) sloughing of dead tissue leaves areas of vacant skeleton between the two grafted individuals. Allograft rejection reactions in sponges have many of the hallmarks of histoincompatibility reactions in higher animals. Although there could be different alloimmune mechanisms operating in different animals, the salient events of allorecognition and antagonistic rejection appear strikingly similar among diverse multicellular animals. 相似文献
9.
Adversarial safety analysis: borrowing the methods of security vulnerability assessments 总被引:2,自引:0,他引:2
Johnston RG 《Journal of Safety Research》2004,35(3):245-248
INTRODUCTION: Safety and security share numerous attributes. The author, who heads the (Security) Vulnerability Assessment Team at Los Alamos National Laboratory, therefore argues that techniques used to optimize security might be useful for optimizing safety. OPTIMIZING SECURITY: There are three main ways to attempt to improve security-security surveys, risk assessment (or "design basis threat"), and vulnerability assessments. The latter is usually the most effective. SAFETY ANALOGS: Vulnerability assessment techniques used to improve security can be applied to safety analysis--even though safety is not ordinarily viewed as having malicious adversaries (other than hazards involving deliberate sabotage). Thinking like a malicious adversary can nevertheless have benefits in identifying safety vulnerabilities. SUGGESTIONS: The attributes of an effective safety vulnerability assessment are discussed, and recommendations are offered for how such an adversarial assessment might work. CONCLUSION: A safety vulnerability assessment can potentially provide new insights, a fresh and vivid perspective on safety hazards, and increased safety awareness. 相似文献
10.
Hult M Martínez Canet MJ Johnston PN Komura K 《Journal of environmental radioactivity》2002,60(3):307-318
During the JCO-accident in Tokai-mura in 1999, the surrounding village was irradiated by an uncontrolled neutron flux. At some locations in that village, the thermal neutron flux was determined retrospectively by measurement of the very low activity of 51Cr and 60Co in stainless-steel spoons using gamma-ray spectrometry in underground laboratories. Activities determined in the HADES underground facility are presented here, together with calibrations performed using a well-defined thermal neutron flux to directly estimate the fluence of thermal neutrons independent of most assumptions. The results show measurable 51Cr in three samples and 60Co in four samples taken from locations at distances of up to 430m from the accident location despite the elapse of 4 half-lives of 51Cr before measurement. Effects of air transport of the samples were considered and shown to be negligible. 相似文献