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

1976 ◽  
Vol 54 (6) ◽  
pp. 825-842 ◽  
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.

Porcellio spinicornis Say (Isopoda) demography. III. A comparison between field data and the results of a simulation model

1976 ◽  
Vol 54 (12) ◽  
pp. 2174-2184 ◽  
Author(s):  
Donald James McQueen
Keyword(s):  
Population Growth ◽  
Simulation Model ◽  
Field Data ◽  
Survival Rates ◽  
Laboratory Data ◽  
Individual Growth ◽  
Growth And Survival ◽  
Life History Stages ◽  
Demographic Rates ◽  
Rates Of Growth

A simulation model for a Porcellio spinicornis Say population was constructed using laboratory data for rates of growth, reproduction, and survival and using winter survival rates observed in the field. The simulated output was compared with field data collected from 1971 to 1973. The expected and observed weight distributions and reproductive periodicities showed good agreement. The expected and observed patterns of numerical change also agreed for all life-history stages, except 18-month-old individuals, which disappeared from the field counts more quickly than expected. Sensitivity analysis showed that the time at which reproduction began each year was not as critical to population growth as were the effects of minor shifts in temperature on individual growth and survival rates. Furthermore, individual growth rate emerged as the factor having the greatest effect on patterns of population growth. Since the laboratory data on growth was reasonably accurate it is probable that the simulation model adequately describes the processes that determine the changes observed in the field population monitored during this study. All of the evidence indicated that during the period of study the population did not increase or decrease and that temperature conditions modifying demographic rates could have accounted for this observation.

The influence of climatic factors on the demography of the terrestrial isopod Tracheoniscus rathkei Brandt

1976 ◽  
Vol 54 (12) ◽  
pp. 2185-2199 ◽  
Author(s):  
Donald J. McQueen
Keyword(s):  
Life Cycle ◽  
Simulation Model ◽  
Field Data ◽  
Climatic Factors ◽  
Laboratory Data ◽  
Day Length ◽  
Model Output ◽  
Population Limitation ◽  
Growth And Survival ◽  
Rates Of Growth

A field population of the isopod Tracheoniscus rathkei was monitored during 1971, 1972, and 1973. At the same time, laboratory data related to growth, reproduction, and survival were collected and combined to produce a simulation model. The model output was compared with the field data. In the laboratory, T. rathkei required humidities very near 100% relative humidity, day length had no effect on growth rates, and temperature altered rates of growth and survival and determined the periodicity of reproduction. In the field, T. rathkei exhibited a 2-year life cycle, breeding occurred in the spring and summer, and about 83% of the population bred once and 42% bred twice during each year. Juveniles grew throughout the fall, overwintered, reproduced at 1 year of age, continued to grow, overwintered a second time, reproduced again, and died. The simulation model mimicked this pattern with considerable precision. Both the field data and the simulated output suggested that the population expanded during 1971, 1972, and 1973. No mechanisms for population limitation were found.

Determining Safe Levels of Mycotoxins

1984 ◽  
Vol 47 (7) ◽  
pp. 570-575 ◽  
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.

Some Methodology for Appraising Contaminants in Aquatic Systems

1975 ◽  
Vol 32 (10) ◽  
pp. 1852-1859 ◽  
Author(s):  
L. L. Eberhardt
Keyword(s):  
Body Size ◽  
Kinetic Models ◽  
Field Data ◽  
Laboratory Data ◽  
Aquatic Systems ◽  
Commercial Fisheries ◽  
Small Fish ◽  
Aquatic Biota ◽  
Laboratory Studies ◽  
Mercury In Fish

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.

Floral development of Potamogeton densus

1973 ◽  
Vol 51 (3) ◽  
pp. 647-656 ◽  
Author(s):  
U. Posluszny ◽  
R. Sattler
Keyword(s):  
Floral Development ◽  
The Other ◽  
Floral Meristem ◽  
Developmental Sequence ◽  
Initial Activity ◽  
The Third ◽  
Stamen Primordia ◽  
Procambial Strand ◽  
Inflorescence Axis ◽  
Rates Of Growth

The floral appendages of Potamogeton densus are initiated in an acropetal sequence. The first primordia to be seen externally are those of the lateral tepals, though sectioning young floral buds (longitudinally, parallel to the inflorescence axis) reveals initial activity in the region of the lower median (abaxial) tepal and stamen at a time when the floral meristem is not yet clearly demarcated. The lateral (transversal) stamens are initiated simultaneously and unlike the median stamens each arises as two separate primordia. The upper median (adaxial) tepal and stamen develop late in relation to the other floral appendages, and in some specimens are completely absent. Rates of growth of the primordia vary greatly. Though the lower median tepal and stamen are initiated first, they grow slowly up to gynoecial inception, while the upper median tepal appears late in the developmental sequence but grows rapidly, soon overtaking the other tepal primordia. The four gynoecial primordia arise almost simultaneously, although variation in their sequence of inception occurs. The two-layered tunica of the floral apices gives rise to all floral appendages through periclinal divisions in the second layer. The third layer (corpus) is involved as well in the initiation of the stamen primordia. Procambial strands develop acropetally, lagging behind primordial initiation. The lateral stamens though initiating as two primordia each form a single, central procambial strand, which differentiates after growth between the two primordia of the thecae has occurred. A great amount of deviation from the normal tetramerous flower is found, including completely trimerous flowers, trimerous gynoecia with tetramerous perianth and androecium, and organs differentiating partially as tepals and partially as stamens.

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

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.

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

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.

An Experimental Investigation of Desensitization in Phobic Patients

1974 ◽  
Vol 124 (581) ◽  
pp. 392-401 ◽  
Author(s):  
P. Gillan ◽  
S. J. Rachman
Keyword(s):  
Experimental Investigation ◽  
Clinical Outcome ◽  
Laboratory Studies ◽  
Comparative Efficacy ◽  
Fear Reduction ◽  
The Third

The investigation had three major aims. We attempted to repeat and extend the findings of the Gelder, Marks and Wolff (1967) study of the comparative efficacy of desensitization and psychotherapy in the treatment of phobic patients. Our second aim was to isolate the effects of various components of desensitization treatment, in the manner employed in laboratory studies of fear-reduction (e.g. Davison, 1968; Rachman, 1965; Rachman, 1968). The third aim was to collect data on the relationships between psychophysiological changes and clinical outcome.

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

2012 ◽  
Vol 40 (6) ◽  
pp. 1280-1283 ◽  
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.

Laboratory and field studies on the degradation of fipronil in a soil

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1095 ◽  
Author(s):  
Guang-Guo Ying ◽  
Rai Kookana
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Field Studies ◽  
Transformation Product ◽  
Laboratory Studies ◽  
The Third ◽  
High Soil Moisture ◽  
Sulfone Derivatives

Degradation of a new insecticide/termiticide, fipronil, in a soil was studied in the laboratory and field. Three metabolites of fipronil (desulfinyl, sulfide, and sulfone derivatives) were identified from soils after treatment. Laboratory studies showed that soil moisture content had a great effect on the degradation rate of fipronil and products formed. High soil moisture contents (>50%) favored the formation of a sulfide derivative of fipronil by reduction, whereas low soil moisture (<50%) and well-aerated conditions favored the formation of fipronil sulfone by oxidation. Microorganisms in soil accelerated the degradation of fipronil to sulfide and sulfone derivatives. The third transformation product, a desulfinyl derivative, was formed by photodecomposition of fipronil in water and on the soil surface under sunlight. The desulfinyl derivative degraded rapidly in field soils with a half-life of 41–55 days compared with an average half-life of 132 days for fipronil. The half-life of the 'total toxic component' (fipronil and its metabolites) in field soil was 188 days on average.

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