Some Methodology for Appraising Contaminants in Aquatic Systems

Kinetic models for uptake and retention of various contaminants by aquatic biota are recommended as a useful means of summarizing and intercomparing laboratory studies, and as essential tools in analyzing field data. Some simple models are fitted to laboratory data on the uptake and retention of DDT and dieldrin by fish. The well-known relation between metabolic rate and body size is used to appraise data and concentrations of DDT, PCBs, and mercury in fish taken from lakes and oceans. Evidence suggests that uptake and retention experiments performed on small fish give very different results from those expected on individuals important in sports or commercial fisheries.

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Porcellio spinicornis Say (Isopoda) demography. II. A comparison between field and laboratory data

Canadian Journal of Zoology ◽

10.1139/z76-094 ◽

1976 ◽

Vol 54 (6) ◽

pp. 825-842 ◽

Cited By ~ 13

Author(s):

Donald J. McQueen

Keyword(s):

Field Data ◽

Laboratory Data ◽

Field Population ◽

Laboratory Studies ◽

The Third ◽

Terrestrial Isopod ◽

Independent Laboratory ◽

Demographic Study ◽

June July ◽

Rates Of Growth

Field data from a demographic study of the terrestrial isopod Porcellio spinicornis Say were analyzed and compared with laboratory data reported by McQueen and Carnio. On the study area, which covered 482.8 m2, it was observed that reproduction began when average temperatures were > 13 °C, and that about 86% of the individuals produced one brood and about 30% produced two broods. During 1972, 25 654 offspring were produced and during 1973, 27 664 offspring resulted from reproduction, which took place during May, June, July, and August. By October of both years, these animals attained sizes ranging from 10 to 30 mg and exhibited 42 to 47% survivorship. During the next summer, females grew to between 30 and 50 mg and males to between 20 and 40 mg, and survivorship ranged from 15% in May to 2% in August. During the third summer, females attained sizes ranging from 80 to 100 mg and males from 40 to 70 mg. Survivorship during this period ranged from 1% in May to 0% in August. All rates of growth, reproduction, and survival, as well as reproductive periodicity, agreed with independent laboratory studies conducted under controlled conditions. During the 3 years studied the field population remained relatively constant and appeared to be limited by temperature conditions.

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Determining Safe Levels of Mycotoxins

Journal of Food Protection ◽

10.4315/0362-028x-47.7.570 ◽

1984 ◽

Vol 47 (7) ◽

pp. 570-575 ◽

Cited By ~ 29

Author(s):

PAT B. HAMILTON

Keyword(s):

Data Base ◽

Field Data ◽

Laboratory Data ◽

Epidemiological Studies ◽

Animal Experimentation ◽

Laboratory Studies ◽

Safe Level ◽

Subjective Evaluations ◽

Increasing Risk

The establishing of safe levels of mycotoxins to date has been a legal rather than scientific exercise. This has resulted in levels which have varied in response to economic and political pressures. The data base for rationally determining safe levels is very small. This has resulted in subjective evaluations of the worth of different studies in attempts to deduce safe levels from experiments designed to demonstrate effects, and in assumed safe levels which vary from field experiences. Using physiological parameters other than growth as criteria of safety, known deleterious interactions of mycotoxins with other factors, and statistical corrections for inadequate numbers of animals tested, permit better agreement between safe levels determined from laboratory data and from field data. However, the number of animals required makes impractical the laboratory determination of truly safe levels. Well-conceived and executed epidemiological studies coupled with laboratory studies designed to elaborate underlying principles appear to be the best approach to determining safe levels of mycotoxins. Until safe levels are based on sound animal experimentation, the prudent person would assume there is no truly safe level and that increasing levels of mycotoxins carry increasing risk.

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COMPOSITION, MICROSTRUCTURE AND PROPERTIES OF QUATERNARY CLAYS OF THE PRIKHANKAYSKAYA DEPRESSION (PRIMORYE)

Engineering Geology World ◽

10.25296/1993-5056-2019-14-1-20-34 ◽

2019 ◽

Vol 14 (1) ◽

pp. 20-34

Author(s):

T. G. RYASHCHENKO ◽

N. N. UKHOVA ◽

S. I. SHTELMAKH ◽

N. I. BELYANINA ◽

P. S. BELYANIN

Keyword(s):

Clay Minerals ◽

Laboratory Data ◽

Chemical Properties ◽

Exchange Capacity ◽

Climatic Conditions ◽

Water Soluble ◽

Laboratory Studies ◽

Microstructural Parameters ◽

Physical Chemical ◽

Study Results

The article considers the study results of composition, microstructure and physical-chemical properties of the quaternary clays of the Prikhankayskaya depression in district of the lake Khanka (Primorye) on the example of air-dry samples of geological borehole 45-b in the range of 18–62 m. The objective of research was to obtain new information about the properties of widespread clay sediments in this area using geologic-lithological materials and laboratory data. The schematic geologic-lithological column was composed with the selection of various zones in the quaternary clay sediments section and the border with sediments of the Neogene System. The methodological scheme of laboratory studies of clays was proposed. This scheme includes the determination of chemical and microelement composition, clay minerals, contents of carbonates, water-soluble salts, mobile forms of aluminum oxide, humus, as well as microstructural parameters (method «Microstructure») and some physical-chemical properties. Geochemical coefficients (Kz, CIA, CIW, ICV) determined the degree of chemical maturity of clays and confirmed the results of palynological studies reflecting the fluctuations of the climatic conditions of their formation. For the group of toxic microelements for the first time the special indicator (Zc) was calculated. Which was the criterion for a degree of pollution of the clay sediments section. Clay minerals of the quaternary clays are represented by smectite and hydromica. The clear change in the mineral association was found when passing to the Neogene sediments (kaolinite prevails). The method «Microstructure» revealed the aggregated type of clays microstructure, the domination of the particles of coarse dust fraction among the primary (free) particles and the almost complete absence of the particles of fine-grained sand fraction, the participation of various fractions in the composition of aggregates. The variants of the formation of certain types of aggregates (on sizes) in the fluviolacustrine «khankayskiy» clays are presented. Solid part density, water resistance (soaking time), sedimentation volume, plasticity, relative swelling (samples-pastes) were determined using standard methods for clays. By special methods, the cation exchange capacity was measured and the calculated values of the plasticity index were obtained from forecasting formulas using the yield limit. The proposed methodological scheme of complex laboratory studies of clay sediments can be recommended for problematic geologic-lithological and engineering-geological sections.

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Scaling the feeding mechanism of the largemouth bass (Micropterus salmoides): motor pattern

Journal of Experimental Biology ◽

10.1242/jeb.198.5.1161 ◽

1995 ◽

Vol 198 (5) ◽

pp. 1161-1171 ◽

Cited By ~ 18

Author(s):

P Wainwright ◽

B Richard

Keyword(s):

Body Size ◽

Largemouth Bass ◽

Standard Length ◽

Prey Capture ◽

Micropterus Salmoides ◽

Motor Pattern ◽

Onset Time ◽

Small Fish ◽

Scaling Effects ◽

Emg Signal

We present the first analysis of scaling effects on the motor pattern of a feeding vertebrate. Data are presented for the effects of body size on the pattern of activity in four head muscles during prey capture in the largemouth bass, Micropterus salmoides. Electromyographic (EMG) recordings were made from three expansive-phase muscles (the epaxialis, the sternohyoideus and the levator arcus palatini) and one compressive-phase muscle (the adductor mandibulae), during the capture of small fish prey. Recordings were made of 181 prey-capture events from 19 bass that ranged in size from 83 to 289 mm standard length. We measured seven variables from the myogram of each capture to quantify the temporal pattern of muscle activation, including the duration of activity in each muscle and the onset time of each muscle, relative to the onset of the sternohyoideus muscle. Regressions of the mean value of each variable for the 19 individuals on standard length revealed that only the onset time of the adductor mandibulae changed with fish body size. The increase in onset time of the adductor muscle appears to reflect the longer time taken to open the mouth fully in larger fish. Other research shows that the kinematics of the strike in this species slows significantly with increasing body size. The combined results indicate that the duration of the EMG signal is not directly correlated with the duration of force production in muscles when compared between fish of different sizes. The lack of scaling of burst duration variables suggests that the reduced speeds of prey-capture motion are explained not by changes in the envelope of muscle activity, but rather by the effects of scale on muscle contractile kinetics. These scaling effects may include changes in the relative resistance of the jaw and head structures to movement through water and changes in the intrinsic contractile properties of the muscles of the feeding apparatus.

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New correlations for predicting two-phase electrical submersible pump performance under downhole conditions using field data

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-021-01392-y ◽

2021 ◽

Author(s):

Thuy Chu ◽

Tan C. Nguyen ◽

Jihoon Wang ◽

Duc Vuong

Keyword(s):

Experimental Data ◽

Field Data ◽

Laboratory Data ◽

Performance Curve ◽

Submersible Pump ◽

Two Phase ◽

Experimental Conditions ◽

Pump Performance ◽

Free Gas ◽

Electrical Submersible Pump

AbstractElectrical Submersible Pump (ESP) is one of the major Artificial Lift methods that is reliable and effective for pumping high volume of fluids from wellbores. However, ESP is not recommended for applications with high gas liquid ratio. The presence of free gas inside the pump causes pump performance degradation which may lead to problems or even failure during operations. Thus, it is important to investigate effect of free gas on ESP performance under downhole conditions. At present, existing models or correlations are based on/verified with experimental data. This study is one of the first attempts to develop correlations for predicting two-phase gas–liquid pump performance under downhole conditions by using field data and laboratory data. Field data from three oil producing wells provided by Strata Production Company and Perdure Petroleum LLC. as well as experimental data obtained from experimental facility at Production and Drilling Research Project—New Mexico Tech were used in this study. Actual two-phase pump differential pressure per stage is obtained from experiments or estimated from field data and was normalized using pump performance curve. The values are compared to pump performance curve to study the relationships between pump performance and free gas percentage at pump intake. Correlations to predict ESP performance in two-phase flow under downhole and experimental conditions was derived from the results using regression technique. The correlation developed from field data presented in this study can be used to predict two-phase ESP performance under downhole conditions and under high gas fraction. The results from the experimental data confirm the reliability of the developed correlation using field data to predict two-phase ESP performance under downhole conditions. The developed correlation using the laboratory data predicts quite well the two-phase pump performance at the gas fraction of less than 15% while it is no longer reliable when free gas fraction is more than 15%. The findings from this study will help operating companies as well as ESP manufacturers to operate ESPs within the recommended range under downhole conditions. However, it is recommended to use the proposed correlation on reservoirs with conditions similar to those of the three presented wells.

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Rates and potential mechanism of anaerobic nitrate-dependent microbial pyrite oxidation

Biochemical Society Transactions ◽

10.1042/bst20120102 ◽

2012 ◽

Vol 40 (6) ◽

pp. 1280-1283 ◽

Cited By ~ 14

Author(s):

Julian Bosch ◽

Rainer U. Meckenstock

Keyword(s):

Electron Acceptor ◽

Pyrite Oxidation ◽

Laboratory Data ◽

Laboratory Studies ◽

Mineral Phase ◽

Terminal Electron Acceptor ◽

Micro Organisms ◽

Open Question ◽

Sulfur Containing ◽

Positive Results

Pyrite (FeS2) is a major iron- and sulfur-containing mineral phase in the environment. Oxidation of pyrite by aerobic micro-organisms has been well investigated. However, the reactivity of pyrite under anoxic conditions is still an open question. In the present paper, we summarize field and laboratory data on this chemolithotrophic respiration process with nitrate as terminal electron acceptor. Geochemical and stable isotope field data indicate that this process is occurring. Laboratory studies are more ambiguous, but recent positive results provide evidence that anaerobic microbial pyrite oxidation can, in fact, occur with nitrate as electron acceptor.

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Pectoral fin locomotion in the striped surfperch. II. Scaling swimming kinematics and performance at a gait transition

Journal of Experimental Biology ◽

10.1242/jeb.199.10.2243 ◽

1996 ◽

Vol 199 (10) ◽

pp. 2243-2252 ◽

Cited By ~ 6

Author(s):

E Drucker ◽

J Jensen

Keyword(s):

Body Size ◽

Swimming Speed ◽

Beat Frequency ◽

Small Fish ◽

Maximal Velocity ◽

Pectoral Fin ◽

Gait Transition ◽

Transition Speed ◽

Aspect Ratios ◽

And Performance

In this study, we report the first allometric equations relating gait parameters and swimming speed to body size for fish employing pectoral fin locomotion. Comparisons of locomotor kinematics and performance among striped surfperch (Teleostei: Embiotocidae) are made at the pectoralcaudal gait transition speed (Up-c). Up-c is considered to elicit physiologically equivalent levels of exercise in animals varying over 100-fold in body mass (Mb) by virtue of dynamically similar pectoral fin movements (constant duty factor, length-specific stride length and fin-beat amplitude) and size-independent propulsive efficiency. At Up-c, pectoral fin-beat frequency scales in proportion to Mb-0.12±0.03, a size-dependence consistent with that observed for stride frequency in fishes swimming by axial undulatory propulsion and in many running tetrapods. It is proposed that the similarity in the scaling of frequency in these vertebrate groups reflects an underlying similarity in the allometry of the maximal velocity of muscle shortening. Absolute Up-c (m s-1) generally increases with body size, but the fastest speeds are not exhibited by the largest animals. A pattern of declining performance in fish 23 cm in standard length and longer may be related to their disproportionately small fin areas and aspect ratios. The pronounced negative allometry of Up-c expressed as standard body lengths per second indicates that a given length-specific speed does not induce comparable levels of activity in large and small fish. Thus, normalization of swimming speed to body length may not be a sufficient correction for kinematic comparisons across size.

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Pectoral fin locomotion in the striped surfperch. I. Kinematic effects of swimming speed and body size

Journal of Experimental Biology ◽

10.1242/jeb.199.10.2235 ◽

1996 ◽

Vol 199 (10) ◽

pp. 2235-2242 ◽

Cited By ~ 9

Author(s):

E Drucker ◽

J Jensen

Keyword(s):

Body Size ◽

Swimming Speed ◽

Beat Frequency ◽

Limited Range ◽

The Body ◽

Small Fish ◽

Large Fish ◽

Pectoral Fin ◽

Transition Speed ◽

Speed Up

Swimming trials at increasing velocity were used to determine the effects of steady swimming speed on pectoral fin kinematics for an ontogenetic series of striped surfperch Embiotoca lateralis, ranging from 6 to 23 cm in standard length (SL). The fin stroke cycle consisted of a propulsive period, the duration of fin abduction and adduction, and a 'refractory' period, during which the fin remained adducted against the body. Pectoral fin-beat frequency (fp) measured as the inverse of the entire stride period, as in past studies, increased curvilinearly with speed. Frequency, calculated as the reciprocal of the propulsive period alone, increased linearly with speed, as shown previously for tail-beat frequency of fishes employing axial undulation. Fin-beat amplitude, measured as the vertical excursion of the pectoral fin tip during abduction, increased over a limited range of low speeds before reaching a plateau at 0.350.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoralcaudal gait transition speed (Up-c), frequency and amplitude attained maxima, suggesting that the fin musculature reached a physiological limit. The effects of body size on swimming kinematics differed according to the method used for expressing speed. At a given absolute speed, small fish used higher stride frequencies and increased frequency at a faster rate than large fish. In contrast, the relationship between fp and length-specific speed (SL s-1) had a greater slope for large fish and crossed that for small fish at high speeds. We recommend that comparisons across size be made using speeds expressed as a percentage of Up-c, at which kinematic variables influencing thrust are size-independent.

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Laboratory Studies of Cirrus Cloud Processes

Cirrus ◽

10.1093/oso/9780195130720.003.0009 ◽

2002 ◽

Author(s):

Paul DeMott

Keyword(s):

Laboratory Data ◽

Ice Formation ◽

Formation Mechanisms ◽

Laboratory Studies ◽

Theoretical Concepts ◽

Upper Troposphere ◽

Microphysical Properties ◽

Nucleation Mechanisms ◽

Remote Measurements ◽

Many Sources

A number of processes that play a role in the formation, evolution of microphysical properties, and radiative characteristics of cirrus clouds are amenable to investigation in a laboratory setting. These laboratory studies provide fundamental data for quantifying and validating theoretical concepts and help guide investigations involving direct and remote measurements of cirrus. Laboratory data also may be used for formulating parameterizations for numerical cloud models, especially where information is incomplete or full descriptions are not possible. This chapter reviews results from laboratory studies of ice formation, ice crystal growth, radiative transfer, and aerosol scavenging and transformation in the cirrus environment. Emphasis is placed on ice formation in cirrus conditions. The related topic of contrail formation is covered separately in this book. The formation mechanisms of lower stratospheric clouds are reviewed elsewhere (e.g., Tolbert 1994; Peter 1996; Carslaw et al. 1997; Koop et al. 1997a). Laboratory studies of cirrus ice formation are at a rapidly developing stage, so it is useful to provide significant background bases for current and needed studies. Key issues are aerosol composition, ice nucleation mechanisms, and the synergy between theory and laboratory measurements. Vali (1996), Baker (1997) and Martin (2000) discuss some of these issues in review papers. Upper tropospheric aerosol particles play an important catalytic role in the formation of cirrus. The nucleation process is important in determining the microphysical properties of cirrus. Numerical modeling studies (e.g., Jensen and Toon 1994; DeMott et al. 1994, 1997; Heymsfield and Sabin 1989) indicate that variation in the factors that drive the nucleation of ice and variations in the physical and chemical characteristics of aerosol particle populations lead to the formation of cirrus with different microphysical characteristics. Knowledge of the physics and chemistry of aerosols in the upper troposphere and lower stratosphere has evolved at a rapid pace. A detailed accounting of this topic is beyond the scope of this chapter. For the purpose of the present discussion, it is sufficient to note that the aerosol from which cirrus nucleate may vary significantly from place to place. Differences in aerosol properties in time and space occur because particles can arrive to the upper troposphere in so many ways and from so many sources.

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