The effects of pesticides on life in fresh waters

1972 ◽  
Vol 180 (1061) ◽  
pp. 383-394 ◽  
Keyword(s):  
Laboratory Experiments ◽  
Organophosphorus Compounds ◽  
Analytical Techniques ◽  
Toxicity Tests ◽  
Limited Data ◽  
Fish Kills ◽  
Test Species ◽  
Fresh Waters ◽  
Short Period ◽  
Rivers And Lakes

About sixty pesticides are estimated to be used in Britain in circumstances where some contamination of fresh waters could occur. Apart from major fish kills, most of the evidence of contamination must be obtained from chemical analyses of water or fish, although these are mainly restricted to a few organochlorine and organophosphorus compounds. The potential hazards to fish and invertebrates have been identified in laboratory experiments and toxicity tests, but routine population surveys of susceptible species in rivers and lakes are rarely made. The nature of possible environmental effects of various types of pesticides is described, and the information on toxic levels of some chemicals, obtained from laboratory tests, is compared with the limited data available on levels existing in the environment. The need for more extensive screening of pesticide chemicals, especially the more persistent types, is discussed. Both adult fish and fry of several species should be used in tests, as well as representative invertebrates, which are known to be more susceptible to some pesticides than are fish. Long-period tests are also required, as for some pesticides the lethal concentrations are much lower in extended tests than in the usual short-period tests. Where possible, the test species, whether fish or invertebrates, should be analysed for the chemical under test. Analytical techniques should be developed, for levels existing in the environment, of a wider range of compounds than is currently investigated.

Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

Analysis of power law assumptions for short-period comets and Kuiper bodies

1999 ◽  
Vol 173 ◽  
pp. 289-293 ◽  
Author(s):  
J.R. Donnison ◽  
L.I. Pettit
Keyword(s):  
Power Law ◽  
Pareto Distribution ◽  
Limited Data ◽  
Short Period ◽  
Probability Plots ◽  
Exponential Probability

AbstractA Pareto distribution was used to model the magnitude data for short-period comets up to 1988. It was found using exponential probability plots that the brightness did not vary with period and that the cut-off point previously adopted can be supported statistically. Examination of the diameters of Trans-Neptunian bodies showed that a power law does not adequately fit the limited data available.

scholarly journals Incidence of Delirium in Hospitalized Children with Cancer

2019 ◽  
Vol 4 (2) ◽  
Keyword(s):  
Cognitive Deficits ◽  
Pediatric Intensive Care ◽  
Limited Data ◽  
Statistical Manual ◽  
Diagnostic And Statistical Manual ◽  
Dsm V ◽  
Increased Risk ◽  
Short Period ◽  
Fluctuating Course

Delirium is defined in the Diagnostic and Statistical Manual of Mental Disorders: Fifth edition (DSM-V) as a “disturbance and change in attention and awareness from baseline that develops over a short period of time, with fluctuating course” [1]. Delirium occurs as a result of factors related to primary illness, the treatment of that illness, and stressful and disorientating environment of the hospital [2]. There are limited data to describe the incidence of delirium in children hospitalized with cancer [3]. Delirium occurs frequently in adults and is an independent predictor of mortality, increased length of stay, and increased risk for long-term cognitive deficits [3]. The prevalence of delirium in hospitalized adults ages 18-56 with cancer ranges from 18%-44% [4]. Most pediatric studies on delirium focus on the critically ill child in the pediatric intensive care unit (PICU). It is estimated that the incidence of delirium in this population is as high as 29% [5].

Methodologies for Evaluating and Qualifying External Pipeline Coatings for Northern Pipelines

2006 ◽  
Author(s):  
S. Papavinasam ◽  
A. Doiron ◽  
T. Panneerselvam ◽  
Y. Lafrenie`re ◽  
M. Attard ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Low Temperatures ◽  
Laboratory Experiments ◽  
Field Experiments ◽  
Climatic Conditions ◽  
Limited Data ◽  
The North

The design of coatings must be adequate to protect pipelines under long-term, severe environmental conditions, including the extreme climatic conditions that will apply in the North before the pipe is installed and operation begins. Practices and standardised methodologies for evaluating and qualifying pipeline coatings for application in northern pipelines are discussed. Results from laboratory and field experiments, carried out under the conditions to which coatings will be exposed during construction, are presented. Based on 1-year laboratory experiments in which samples were exposed to temperatures as low as −45°C and limited data from the field experiments, it is concluded that Canadian Standards Association (CSA) standards CSA Z662, CSA Z245.20 and CSA Z245.21 adequately cover evaluation of coatings for northern pipelines. However, in order to evaluate the effects of low-temperatures, the specimens should be exposed for at least 4 months. Coatings qualified by CSA Z245.21 (System B1 and B2) are less affected from exposure to low-temperatures than those qualified by CSA Z245.21 (System A1) and CSA Z245.20.

A new method for early assessment of effects of exposing two non-target crustacean species, Asellus aquaticus and Gammarus fossarum, to pesticides, a laboratory study

2010 ◽  
Vol 26 (4) ◽  
pp. 217-228 ◽  
Author(s):  
Simon Lukančič ◽  
Uroš Žibrat ◽  
Tadej Mezek ◽  
Andreja Jerebic ◽  
Tatjana Simčič ◽  
...  
Keyword(s):  
Stress Factors ◽  
Toxicity Tests ◽  
Asellus Aquaticus ◽  
Early Assessment ◽  
Short Term ◽  
Aquatic Animals ◽  
Test Species ◽  
Gammarus Fossarum ◽  
Ets Activity ◽  
Short Term Exposure

A reliable method is needed for assessing the condition of aquatic animals and their resistance to toxic pollutants. The physiological responses of two freshwater crustaceans, Asellus aquaticus and Gammarus fossarum, following in vitro exposure to two pesticides (atrazine and imidacloprid), were measured by a combination of electron transport system (ETS) activity and respiration (R). Short-term exposure concentrations were selected according to standard toxicity tests and ranged from 0.01 mg L—1 to 10 mg L—1. When pesticide concentration was greater than 1 mg l— 1 (which is below the LC50 [48 hours] determined for both species), A. aquaticus and G. fossarum responded to short-term exposure with elevated levels of R and/or lower levels of ETS activity. One hour exposure to concentrations of up to 10 mg L—1 showed an effect in both test species. Laboratory tests confirmed that G. fossarum is more sensitive to short-term pesticide exposure than A. aquaticus. The combination of these two methods provides a useful and effective tool for assessing the general condition of aquatic animals. It also enables to determine toxic effects on freshwater biota of specific or combined pollutants. ETS/R ratio may be used as a quick predictor of effects on organisms exposed to pesticides and other stress factors such as changes in temperature, light, salinity, oxygen concentration and food.

Propagation of viscous currents on a porous substrate with finite capillary entry pressure

2016 ◽  
Vol 801 ◽  
pp. 65-90 ◽  
Author(s):  
Roiy Sayag ◽  
Jerome A. Neufeld
Keyword(s):  
Laboratory Experiments ◽  
Gravity Current ◽  
Fluid Pressure ◽  
Analytical Techniques ◽  
Gravity Currents ◽  
Porous Substrate ◽  
Entry Pressure ◽  
Self Similar ◽  
Capillary Entry Pressure ◽  
Theoretical Results

We study the propagation of viscous gravity currents over a thin porous substrate with finite capillary entry pressure. Near the origin, where the current is deep, propagation of the current coincides with leakage through the substrate. Near the nose of the current, where the current is thin and the fluid pressure is below the capillary entry pressure, drainage is absent. Consequently the flow can be characterised by the evolution of drainage and fluid fronts. We analyse this flow using numerical and analytical techniques combined with laboratory-scale experiments. At early times, we find that the position of both fronts evolve as $t^{1/2}$, similar to an axisymmetric gravity current on an impermeable substrate. At later times, the growing effect of drainage inhibits spreading, causing the drainage front to logarithmically approach a steady position. In contrast, the asymptotic propagation of the fluid front is quasi-self-similar, having identical structure to the solution of gravity currents on an impermeable substrate, only with slowly varying fluid flux. We benchmark these theoretical results with laboratory experiments that are consistent with our modelling assumption, but that also highlight the detailed dynamics of drainage inhibited by finite capillary pressure.

scholarly journals Newly Hatched Stage I American Lobster (Homarus americanus) Survival Following Exposure to Physically and Chemically Dispersed Crude Oil

2021 ◽  
Author(s):  
Benjamin de Jourdan ◽  
Tahereh Boloori ◽  
Les Burridge
Keyword(s):  
Environmental Protection Agency ◽  
Native Species ◽  
Toxicity Testing ◽  
Homarus Americanus ◽  
Larval Survival ◽  
Stage I ◽  
Toxicity Tests ◽  
American Lobster ◽  
Atlantic Canada ◽  
Test Species

Abstract Standard model species are commonly used in toxicity tests due to their biological and technical advantages but studying native species increases the specificity and relevance of results generated for the potential risk assessment to an ecosystem. Accounting for intraspecies variability and other factors, such as chemical and physical characterization of test medium, is necessary to develop a reproducible bioassay for toxicity testing with native species. In this study, larval stage I American lobster (Homarus americanus) was selected as the test species, which is native to Atlantic Canada. Toxicity tests were first conducted exposing lobster larvae to a reference toxicant of copper sulfate (CuSO4) and then to physically and chemically dispersed oil. The effect on larval survival was estimated by calculating the median effect concentration (EC50) as 2.54-9.73 mg TPH/L when all trials are considered together. The HC5 or PNEC value was 2.52 mg TPH/L and therefore a narrow difference from the EC50 value. The inter-trial variability (coefficient of variability = 17%) was lower than the US Environmental Protection Agency standard test species of mysid shrimp (Americamysis bahia) and inland silversides (Menidia bervillina). Our results indicate that the described larval lobster bioassay is reliable to produce repeatable results for this commercially important and native species of Atlantic Canada.

Goals and Development of the Alaska Volcano Observatory Seismic Network and Application to Forecasting and Detecting Volcanic Eruptions

2020 ◽  
Vol 91 (2A) ◽  
pp. 647-659 ◽  
Author(s):  
John A. Power ◽  
Mathew M. Haney ◽  
Stephen M. Botnick ◽  
James P. Dixon ◽  
David Fee ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Volcanic Eruptions ◽  
Seismic Network ◽  
High Rate ◽  
Volcano Observatory ◽  
Short Period ◽  
Volcanic Seismicity ◽  
Volcanic Processes ◽  
Aleutian Arc ◽  
Monitoring Effort

Abstract The Alaska Volcano Observatory (AVO) seismic network has been in operation since 1988 and during this time has grown from 29 to 217 seismic stations providing real-time monitoring of 32 active volcanoes in Alaska, as well as useful data for regional earthquake monitoring. Since 1988, AVO has detected 59 volcanic eruptions at Aleutian arc volcanoes, and 31 of these have been captured by local seismic instrumentation. As part of this monitoring effort, AVO has cataloged more than 120,000 earthquake hypocenters and magnitudes associated with volcanic processes throughout the arc. This high rate of volcanic activity provides an excellent opportunity to study seismicity associated with magmatic and eruptive processes and develop and refine analytical techniques to track volcanic seismicity and warn of hazardous eruptions. The network is currently undergoing an extensive upgrade, replacing aging short-period analog seismometers with digital broadband instruments. These are expected to improve AVO’s seismic capability and further facilitate other geophysical instrumentation such as continuous Global Positioning System receivers, infrasound sensors, and web cams.

Long-Term Programme for Pollution Monitoring and Research in the Mediterranean (MED POL)

1993 ◽  
Vol 27 (7-8) ◽  
pp. 345-352 ◽  
Author(s):  
L. Jeftic
Keyword(s):  
Organophosphorus Compounds ◽  
Scientific Information ◽  
Analytical Techniques ◽  
Pollution Monitoring ◽  
Data Quality Control ◽  
Pollution Levels ◽  
Mediterranean Countries ◽  
The Mediterranean ◽  
Scientific Meetings

Long-term programme for pollution monitoring and research in the Mediterranean (MED POL) was adopted by the Mediterranean countries in 1981. Monitoring of the Mediterranean pollution in the framework of MED POL started in 1983 and at present 16 Mediterranean countries have on-going programmes and are submitting data. Through these programmes pollution is regularly monitored at hundreds of sampling stations. All national research centres involved in monitoring participate in the continuing programme of data quality control which includes intercalibration of sampling and analytical techniques. By the end of 1991, over 400 research projects have been implemented in the framework of MED POL by 150 institutes from 15 Mediterranean countries. Results gathered through the research component of MED POL were presented at numerous scientific meetings and were published in a large number of scientific papers. Data generated through MED POL are used as the basis for the analysis of the present “state of the health” of the Mediterranean and of the trends in pollution levels. They also provide scientific information needed for the formulation of common measures to control pollution. In-depth assessment studies, including concrete recommendations for measures to be taken by the Contracting Parties were completed for microbial pollution, mercury, cadmium, petroleum hydrocarbons, used lubricating oils, organotin compounds, organohalogen compounds, organophosphorus compounds, persistent synthetic materials, radioactive substances and pathogenic microorganisms. Similar assessment studies are being prepared on other subjects.

A viewpoint from the trenches

2019 ◽  
Vol 33 (1) ◽  
pp. 125-130 ◽  
Author(s):  
Paul Sergius Koku
Keyword(s):  
Data Analysis ◽  
Collaborative Research ◽  
Design Methodology ◽  
Qualitative Data ◽  
Analytical Techniques ◽  
Limited Data ◽  
Content Type ◽  
The Past ◽  
The Future ◽  
Practical Implications

Purpose This paper aims to present the author’s viewpoint on the developments in the Journal of Services Marketing (JSM) during the past 25 years of his association with the Journal. The paper documents the evolution in the Journal, highlights significant changes and makes some prognostications for the future. Design/methodology/approach The paper relies on the first-hand account of the author, which is supplemented by limited qualitative data analysis that consists of analyzing keywords and the abstract of articles published in JSM during the past 25 years. Findings The first-hand account shows that JSM has undergone changes that reflect changes that have taken place in the field of marketing. The issues/topics of manuscripts submitted and published in the Journal have become interdisciplinary and so are the analytical techniques. This expanding scope of the Journal positions it well for the future in which collaborative research will be more pervasive in the academy. Research limitations/implications This is a first-hand account with limited data analysis and therefore could suffer from the writer’s biases even though they might be unintended. Practical implications This paper documents the expanding scope of the Journal that may have been the result of explicit steps taken to make the Journal more successful in the future. Originality/value As a first-hand account, this study is original.

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