Effects of temperature and host density on the snail-finding capacity of cercariae of Echinostoma caproni (Digenea: Echinostomatidae)

Parasitology ◽  
1991 ◽  
Vol 102 (3) ◽  
pp. 391-395 ◽  
Author(s):  
D. Meyrowitsch ◽  
N. Ø. Christensen ◽  
O. Hindsbo
Keyword(s):  
Experimental Studies ◽  
Host Density ◽  
Snail Host ◽  
Effect Of Temperature ◽  
Density Range ◽  
Echinostoma Caproni ◽  
Snail Density ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Infective Period

The effect of temperature (19–36 °C) and snail host density (0.014–10 snails/1) on the snail-finding capacity of Echinostoma caproni cercariae is described. The initial swimming speed increased whereas the length of the infective period decreased with increasing temperature. The combined effect resulted in the E. caproni cercarial snail-finding capacity being temperature independent in the range 19 to 36 °C at a snail density of 0·014 snails/1. A moderate temperature dependency was, however, seen at a lower snail density. The cercarial snail-finding capacity was snail-host density dependent in the density range 0.014 to 1 snail/1. The findings from this study show that a relatively low and biologically realistic snail host density must be used in experimental studies if realistic estimates of the dynamics of cercarial transmission are to be obtained.

The effects of temperature and pH on the embryonic development of two species of Triturus (Caudata: Salamandridae)

2007 ◽  
Vol 28 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Leonardo Vignoli ◽  
Marco Bologna ◽  
Manuela D'Amen
Keyword(s):  
Mortality Rate ◽  
Embryonic Development ◽  
Effect Of Temperature ◽  
Acidic Ph ◽  
Larval Life ◽  
Experimental Conditions ◽  
Rate Of Development ◽  
Constant Ph ◽  
Effects Of Temperature ◽  
Increasing Temperature

AbstractAmphibian populations are especially sensitive to aquatic parameters, in particular during embryonic and larval life. Our aim was to test for an effect of temperature (T = 13°C, 20°C and 25°C at constant pH = 7) and pH (pH = 5.5, 7 and 8.5 at constant T= 20°C) on embryos of two species of Triturus, T. carnifex carnifex and T. italicus (Amphibia, Salamandridae) using GLM procedure. Trend of embryogenesis processes, time to hatching and rate of development have a similar effect in both species in the used range of temperature and pH. Time to hatching decreased significantly with the increasing temperature. The pH experimental conditions had no effect on T. carnifex embryos survival, while the acidic pH condition raised the mortality rate in T. italicus, whose embryos should be more vulnerable than those of T. carnifex to acidification in nature.

Effects of temperature on survival, infectivity and in vitro encystment of the cercariae of Echinostoma caproni

2003 ◽  
Vol 77 (3) ◽  
pp. 235-238 ◽  
Author(s):  
B. Fried ◽  
E.L. Ponder
Keyword(s):  
Spring Water ◽  
Helisoma Trivolvis ◽  
Echinostoma Caproni ◽  
Maximal Life Span ◽  
Different Temperatures ◽  
Effects Of Temperature ◽  
Effects Of Aging ◽  
C 78 ◽  
Infective Period

AbstractThe effects of temperature on survival, infectivity and in vitro encystment of Echinostoma caproni cercariae in artificial spring water (ASW) were studied. Effects of aging cercariae in ASW at various temperatures showed that at 23°C cercariae achieved 50% survival in 24 h, compared to 92 h at 12°C. Cercariae aged in ASW at 28 and 37.5°C showed 50% survival at 16 and 10 h, respectively. Cercariae aged at different temperatures for various times were used to infect juvenile Helisoma trivolvis (Colorado strain) snails maintained in ASW at 23°C. Index of infectivity was based on counting encysted metacercariae in the snails at 8 to 12 h post-infection. Cercariae aged at 23, 28 and 37.5°C showed 50% encystment at 6, 8 and 4 h, respectively. Cercariae aged at 4°C showed 50% encystment in 10 h and cercariae aged at 12°C showed 50% encystment beyond 16 h. Cercariae showed maximal longevity and infectivity in snails when aged at 12°C in ASW. For E. caproni, as in other digeneans, the infective period of cercariae is markedly shorter than the maximal life-span at any given temperature. Studies on in vitro encystment of E. caproni cercariae in Locke's solution:ASW (1:1) showed that encystment was optimal at 23°C (78% encystment) and that it declined to 44% at 28°C and became almost nil (0.02%) at 12 or 37.5°C.

Effect of Temperature and Water Immersion on the Mechanical Properties of Coated Fabrics

2010 ◽  
Vol 129-131 ◽  
pp. 230-234
Author(s):  
Ying Ying Zhang ◽  
Qi Lin Zhang ◽  
Chuan Zhi Zhou ◽  
Ying Zhou
Keyword(s):  
Mechanical Properties ◽  
Water Immersion ◽  
Effect Of Temperature ◽  
C 23 ◽  
Different Temperatures ◽  
Temperature Induction ◽  
Effects Of Temperature ◽  
C 50 ◽  
Coated Fabrics ◽  
Increasing Temperature

As composite, the mechanical properties of coated fabrics are sensitive to environment. This paper presented mechanical properties under different environments. A list of uniaxial tests are carried out under different temperatures including -20°C, 0°C, 23°C, 50°C, and 70°C. First, the tensile behaviors at room temperature and the failure behaviors are studied. Then, the effects of temperature on mechanical properties are determined. Finally, the effects of water immersion on mechanical properties are discussed. Results show PTFE coated fabrics remained unchanged in varying temperature and humidity. The temperature has effects on the mechanical properties of PVC coated fabrics. With increasing temperature, the strength decrease and the strain at break increase. The temperature induction factors are proposed for the design and analysis. The water immersion has little effect on the mechanical properties because of the impervious coating.

scholarly journals Effect of Temperature and Pressure of Supercritical CO2 on Dewatering, Shrinkage and Stresses of Eucalyptus Wood

2021 ◽  
Vol 11 (18) ◽  
pp. 8730
Author(s):  
Lin Yang
Keyword(s):  
Residual Stress ◽  
Supercritical Co2 ◽  
Tangential Direction ◽  
Effect Of Temperature ◽  
Eucalyptus Wood ◽  
Conventional Kiln Drying ◽  
Effects Of Temperature ◽  
Temperature And Pressure ◽  
Capillary Tension ◽  
Increasing Temperature

Supercritical CO2 (SuCO2) dewatering can mitigate capillary tension and reduce wood collapse. In this study, Eucalyptus urophylla × E. grandis specimens were dewatered by SuCO2 at temperatures of 35, 40 and 55 °C, in pressures of 10 and 30 MPa, respectively, for 1h. Effects of temperature and pressure on dewatering rate, moisture content (MC) distribution and gradient, shrinkage and residual stress of wood after dewatering were investigated. The results indicate that the SuCO2 dewatering rate is much faster than that of conventional kiln drying (CKD). The dewatering rate increases with increasing of temperature and pressure; however, pressure has a significant influence, especially for the high-temperature dewatering process; the MC distribution after 1 h dewatering is uneven and MC gradients decrease with reducing of mean final MC of wood. MC gradients along radial direction are much smaller than that in tangential direction; collapse of wood significantly reduces after dewatering due to SuCO2 decreasing the capillary tension, and residual stress of wood during dewatering is mainly caused by pressure of SuCO2, which decreases with increasing temperature. SuCO2 dewatering has great potential advantages in water-removal of wood prone to collapse or deformation.

Effect of temperature on the nonlinear dynamic behavior of two-lobe non-circular gas-lubricated micro-bearings

2021 ◽  
pp. 135065012199568
Author(s):  
Azizmohammad Gharanjik ◽  
Ardeshir Karami Mohammadi
Keyword(s):  
Dynamic Behavior ◽  
High Temperatures ◽  
Nonlinear Dynamic ◽  
Phase Portraits ◽  
Effect Of Temperature ◽  
Behavior Changes ◽  
Runge Kutta Method ◽  
Nonlinear Dynamic Behavior ◽  
Effects Of Temperature ◽  
Increasing Temperature

In this paper, the molecular gas lubrication model was used to analyze the nonlinear dynamic behavior of two-lobe non-circular gas-lubricated micro-bearings. The effects of temperature rise are taken into account. At high temperatures, in addition to gas rarefaction, its viscosity and friction will also change, and slip across boundaries will occur. The rarefaction of the lubricating gas film caused by the microscale effect at high temperatures was considered. The effects of temperature and rotation speed (with and without rarefaction effect) on the dynamic behavior of the non-circular micro gas bearing were studied. The nonlinear equation governing the gas behavior is discretized using the finite-element method and then solved simultaneously with the dynamic equations of rotor motion using the fourth-order Runge–Kutta method. Center orbit diagrams, phase portraits, Poincare maps, power spectrum, and bifurcation diagrams are used to investigate the dynamic behavior of two-lobe non-circular gas-lubricated micro-bearings. Some results show that with increasing temperature, the rotor behavior changes from T-periodic to quasi-periodic. It was also observed that at high temperatures, with increasing rotational speed, the behavior of the system changes from T-periodic to quasi-periodic, but if the gas is rarefied, this change occurs at a slower speed.

scholarly journals Effects of temperature on tissue–diet isotopic spacing of nitrogen and carbon in otolith organic matter

2019 ◽  
Vol 70 (12) ◽  
pp. 1757 ◽  
Author(s):  
Jane A. Godiksen ◽  
Ming-Tsung Chung ◽  
Arild Folkvord ◽  
Peter Grønkjær
Keyword(s):  
Stable Isotopes ◽  
Organic Matter ◽  
Ambient Temperature ◽  
Trophic Position ◽  
Effect Of Temperature ◽  
Δ13c Values ◽  
Different Temperatures ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Rearing Experiment

Reconstruction of the trophic position of a fish can be performed by analysing stable nitrogen and carbon isotopes in otolith protein. However, ambient temperature may affect the tissue–diet isotopic spacing of stable isotopes from diet to predator tissue and bias estimates of trophic position. To test this, otolith protein, heart and muscle tissue from a rearing experiment with juvenile cod held at different temperatures (4, 7, 10 and 14°C) were analysed. There was no significant effect of temperature on otolith δ15N, whereas muscle and heart exhibited a slight decrease in δ15N values with increasing temperature corresponding to maximum of 0.6‰ over the 10°C range. By contrast, the otolith protein δ13C values at 4 and 7°C were significantly higher than for 10 and 14°C, suggesting an approximate 1‰ increased tissue–diet enrichment at the lower temperatures. Temperature had no significant effect on muscle and heart δ13C values. Considering the annual mean variation in ocean temperatures, our results indicate that the trophic signals recorded in the otoliths will reflect changes in diet isotope values with little bias from the ambient temperature experienced by the fish.

scholarly journals Modified-atmosphere Packaging of Blueberry Fruit: Effect of Temperature on Package O2 and CO2

1992 ◽  
Vol 117 (3) ◽  
pp. 436-441 ◽  
Author(s):  
Randolph M. Beaudry ◽  
Arthur C. Cameron ◽  
Ahmad Shirazi ◽  
Diana L. Dostal-Lange
Keyword(s):  
Steady State ◽  
Partial Pressure ◽  
Modified Atmosphere Packaging ◽  
Vaccinium Corymbosum ◽  
Effect Of Temperature ◽  
Modified Atmosphere ◽  
Highbush Blueberry ◽  
Partial Pressures ◽  
Effects Of Temperature ◽  
Increasing Temperature

Highbush blueberry (Vaccinium corymbosum L. `Bluecrop') fruit sealed in low-density polyethylene packages were incubated at 0, 5, 10, 15, 20, or 25C until O2 and CO2 levels in the package reached a steady state. A range of steady-state O2 partial pressures (1 to 18 kPa) was created by placing a range of fruit weights within packages having a constant surface area and film thickness. The steady-state O2 partial pressure in packages containing the same weight of fruit decreased as temperature increased, indicating the respiratory rate rose more rapidly (i.e., had a greater sensitivity to temperature) than O2 transmission through the film. Steady-state O2 and CO2 partial pressures were used to calculate rates of O2 uptake. CO2 Production. and the respiratory quotient (RO). The effects of temperature and 02 partial pressure on O2 uptake and CO2 production and the RQ were characte∼zed. The steady-state O, partial pressure at which the fruit began to exhibit anaerobic CO2 production (the RQ breakpoint) increased with increasing temperature, which implies that blueberry fruit can be stored at lower O2 partial pressures when stored at lower temperatures.

Theoretical and Experimental Studies on Thermal Consolidations Characteristics of Ningbo Soft Clay

2014 ◽  
Vol 501-504 ◽  
pp. 141-149
Author(s):  
Tie Feng Yin
Keyword(s):  
Extreme Values ◽  
Soft Clay ◽  
Experimental Studies ◽  
Effect Of Temperature ◽  
Consolidation Process ◽  
Confining Pressures ◽  
Degree Of Consolidation ◽  
The Difference ◽  
Increasing Temperature ◽  
The Impact

When considering the effect of temperature, consolidation deformation of the soil is a complex multi-physics coupling problem. For soil of different regions, the influence of temperature on soil physical properties vary widely, even presents the opposite result. In order to realize the thermal consolidations characteristics of Ningbo soft clay, this paper selected Ningbo soft clay and done consolidation test with temperature controlled under different temperatures and confining pressures. Combined with the analysis of theory, this paper carried out the reasonable explanation to the experimenting phenomenon. The results show that: temperature increase the penetration rate of the soil by changing the coefficient of the water, thereby accelerating the consolidation process. The degree of consolidation increases with increasing temperature. In the same conditions and time, the higher the degree of consolidation of soil with increasing temperature, and the difference of the degree of consolidation increases with the increase of the difference in temperature. The difference of the degree of consolidation under different temperature increases with time showing a rapid increase in the extreme values first, and then gradually reduced to zero. Therefore, effect of temperature is mainly reflected in the drainage consolidation process less than half the period of time before, and the greater the temperature difference, the impact effect is more obvious.

Effect of temperature during the synthesis process of CdSe nanoparticles using the colloidal technique

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3389-3395
Author(s):  
R. González-Díaz ◽  
D. Fernández-Sánchez ◽  
P. Rosendo-Francisco ◽  
G. Sánchez-Legorreta
Keyword(s):  
Scanning Tunneling Microscope ◽  
Electron Cloud ◽  
Cdse Nanoparticles ◽  
Effect Of Temperature ◽  
Synthesis Process ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
First Results ◽  
Effects Of Temperature ◽  
Scanning Electron

AbstractIn this work, the first results of the effects of temperature during the production of Se2- ions and the effect during the interaction of Cd2+ and Se2- ions in the synthesis process of CdSe nanoparticles are presented. The synthesis of CdSe was carried out by the colloidal technique, in the first one we used a temperature of 63 °C to produce Se2- ions and in the second one an interaction temperature of 49 °C. The samples were characterized using a Scanning Electron Microscope (SEM) and a Scanning Tunneling Microscope (STM). From the SEM micrographs it was possible to identify the thorns formation and irregular islands. STM micrographs reveal elliptical shapes with a regular electron cloud profile.

scholarly journals Theoretical Effect of Temperature on Threshold in the Hodgkin-Huxley Nerve Model

1966 ◽  
Vol 49 (5) ◽  
pp. 989-1005 ◽  
Author(s):  
Richard Fitzhugh
Keyword(s):  
Relaxation Time ◽  
Relaxation Times ◽  
Giant Axon ◽  
Temperature Curve ◽  
Effect Of Temperature ◽  
Threshold Temperature ◽  
Ionic Conductances ◽  
And Shifts ◽  
The Right ◽  
Increasing Temperature

In the squid giant axon, Sjodin and Mullins (1958), using 1 msec duration pulses, found a decrease of threshold with increasing temperature, while Guttman (1962), using 100 msec pulses, found an increase. Both results are qualitatively predicted by the Hodgkin-Huxley model. The threshold vs. temperature curve varies so much with the assumptions made regarding the temperature-dependence of the membrane ionic conductances that quantitative comparison between theory and experiment is not yet possible. For very short pulses, increasing temperature has two effects. (1) At lower temperatures the decrease of relaxation time of Na activation (m) relative to the electrical (RC) relaxation time favors excitation and decreases threshold. (2) For higher temperatures, effect (1) saturates, but the decreasing relaxation times of Na inactivation (h) and K activation (n) factor accommodation and increased threshold. The result is a U-shaped threshold temperature curve. R. Guttman has obtained such U-shaped curves for 50 µsec pulses. Assuming higher ionic conductances decreases the electrical relaxation time and shifts the curve to the right along the temperature axis. Making the conductances increase with temperature flattens the curve. Using very long pulses favors effect (2) over (1) and makes threshold increase monotonically with temperature.

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