Larval survival characteristics and behaviour of the gill monogenean Discocotyle sagittata

Parasitology ◽  
1998 ◽  
Vol 117 (5) ◽  
pp. 491-498 ◽  
Author(s):  
A. M. GANNICOTT ◽  
R. C. TINSLEY
Keyword(s):  
Survival Time ◽  
Seasonal Changes ◽  
Larval Survival ◽  
Parasite Transmission ◽  
Laboratory Studies ◽  
Temperature Dependent ◽  
Maximum Life Span ◽  
Age Dependent ◽  
Increasing Temperature ◽  
The Relationship

The survival characteristics of Discocotyle sagittata larvae are both age- and temperature-dependent. In laboratory studies at constant temperatures of 6, 10, 13, 18 and 22°C, oncomiracidia had a maximum life-span of 96 h at 6°C, declining with increasing temperature to 26 h at 22°C. Larval swimming activity was also age dependent, and continued for a large proportion of survival time. The relationship between time at which larvae stop swimming as a proportion of total survival time was statistically significant between temperatures. Proportionally, oncomiracidia swam for longer periods at lower temperatures. As oncomiracidia age, they become progressively less active, spending less time in the water column. In contrast to observations recorded in the literature, D. sagittata larvae are infective soon after emergence (within the minimum of 2 h studied), and feed on blood from the gill capillaries within 2 h post-exposure. The temperature-dependent characteristics of the larval stage are likely to have important implications for seasonal changes in parasite transmission.

scholarly journals The influence of temperature on methane adsorption in coal: A review and statistical analysis

2019 ◽  
Vol 37 (9-10) ◽  
pp. 745-763 ◽  
Author(s):  
Zhijun Wang ◽  
Xiaojuan Wang ◽  
Weiqin Zuo ◽  
Xiaotong Ma ◽  
Ning Li
Keyword(s):  
Coalbed Methane ◽  
Methane Adsorption ◽  
Gas Content ◽  
Future Research ◽  
Temperature Dependent ◽  
Current State ◽  
Influence Of Temperature On ◽  
State Of Research ◽  
Increasing Temperature ◽  
The Relationship

The capacity of coal to adsorb methane is greatly affected by temperature and, in recent years, temperature-dependent adsorption has been studied by many researchers. Even so, comprehensive conclusions have not been reached and conflicting experimental results are common. This paper reviews the current state of research regarding the temperature-dependent adsorption of methane in coal and catalogs the conclusions from experiments conducted on that subject by 28 researchers, as published between 1995 and 2017. Probability theory and statistics are used to show that the conclusion generally accepted by most researchers is that the amount of methane adsorbed by coal decreases with increasing temperature. It is highly likely that the Langmuir volume decreases as the temperature rises, and it is also probable that the Langmuir pressure increases at higher temperatures. Equations are presented that express the relationships between methane adsorption, Langmuir volume, Langmuir pressure, and temperature. Future research should be directed toward determining the relationship between Langmuir pressure and temperature. The results of the study presented herein provide a theoretical basis for predicting the gas content in coal seams and improving the efficiency of coalbed methane development.

Permittivity Study of a CuCl Residue at 13–450 °C and Elucidation of the Microwave Intensification Mechanism for Its Dechlorination

2019 ◽  
Vol 38 (2019) ◽  
pp. 135-142
Author(s):  
Guo Zhanyong ◽  
Li Fachaung ◽  
Su Guang ◽  
Zhai Demei ◽  
Cheng Fang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Microwave Irradiation ◽  
Loss Factor ◽  
Elevated Temperatures ◽  
Temperature Dependent ◽  
Positive Interaction ◽  
Increasing Temperature ◽  
Relationship Of ◽  
The Relationship ◽  
Metallurgy Process

AbstractPermittivity is a vitally important parameter for describing the absorbing and heating characteristics of a material under microwave irradiation, and it is also strongly dependent on temperature. However, the literature contains little information on this topic and even less particular permittivity data at elevated temperatures. In this paper, the permittivity of a CuCl residue at temperatures from 13 to 450 °C at 2.45 GHz was measured using the cavity perturbation method. The relationship of its real part (ε′) and imaginary part (ε″) with temperature (T) was deduced. In addition, the temperature-dependent tangent (tan δ) and the penetration depth (d) of microwaves into the material were calculated. The results of the permittivity study show that the dielectric constant (ε′) of the CuCl residue increased linearly with increasing temperature. In contrast, the dielectric loss factor (ε″) and loss tangent first maintained on a steady value between 13 and 300 °C and then substantially increased from 300 to 450 °C. The positive interaction of the dielectric property and temperature showed the reasonableness of our earlier metallurgy process, where the CuCl residue for dechlorination was roasted at 350–450 °C under microwave irradiation.

Experimental studies on the transmission dynamics of the cercariae of Echinoparyphium recurvatum (Digenea: Echinostomatidae)

Parasitology ◽  
1983 ◽  
Vol 87 (1) ◽  
pp. 167-174 ◽  
Author(s):  
N. A. Evans ◽  
D. M. Gordon
Keyword(s):  
Life Span ◽  
Intermediate Host ◽  
Experimental Studies ◽  
Intermediate Hosts ◽  
Maximum Life Span ◽  
Age Dependent ◽  
Second Intermediate Host ◽  
The Mean ◽  
The Relationship ◽  
First Intermediate Host

SUMMARYAge-dependent survival and infectivity characteristics are described for the cercariae of Echinoparyphium recurvatum. At 18 °C the maximum life-span of the cercariae was 48 h and 50% survival occurred at 30·5 h. Infectivity of cercariae to the second intermediate host, Lymnaea peregra was maximal approximately 2 h after emission from the first intermediate host and it subsequently declined to zero at 19 h. It is suggested that the period of sub-maximal infectivity at the beginning of the cercarial life-span may represent a phase during which dispersal is an important function of the larvae. The relationship between infective stage density and establishment success was linear up to densities equivalent to 5000 cercariae/1. At higher cercarial densities the proportion of parasites establishing in second intermediate hosts declined progressively with increasing cercarial density. The mean number of parasites establishing/host increased linearly with increasing host size.

Transmission ofSchistosoma mansonifrom man to snail: experimental studies of miracidial survival and infectivity in relation to larval age, water temperature, host size and host age

Parasitology ◽  
1982 ◽  
Vol 85 (2) ◽  
pp. 339-360 ◽  
Author(s):  
R. M. Anderson ◽  
J. G. Mercer ◽  
R. A. Wilson ◽  
N. P. Carter
Keyword(s):  
Experimental Studies ◽  
Larval Survival ◽  
Host Size ◽  
Host Age ◽  
Infection Rates ◽  
Susceptibility To Infection ◽  
Size Dependent ◽  
Age Dependent ◽  
Influence Of Temperature On ◽  
The Relationship

SUMMARYWe report the results of experimental work on (a) the influence of temperature on the age-dependent survival and infectivity of the mira-cidia ofSchistosoma mansoniand (b) the relationship between snail age, snail size and susceptibility to infection. The death rate of miracidia declined exponentially with age where life-expectancy was maximal (approximately 16 h) at 15 °C. Infectivity also declined rapidly with larval age but, in contrast to larval survival, the rate of infection was at a maximum at 25 °C. Snail susceptibility was shown to be more closely correlated with host size rather than host age. Susceptibility declined exponentially with increased host size. Size-dependent susceptibility was shown to generate concave age-prevalence curves for infection within snail populations, where the maximum prevalence is generated in snails of intermediary age. Simple mathematical models are developed to aid estimation of larval survival and infection rates and experimental results are discussed in relation to the overall transmission success of the parasite from man to snail.

scholarly journals THE ROLE OF MELATONIN DEFICIENCY IN THE GENESIS OF ARTERIAL HYPERTENSION IN PATIENTS WITH CHRONIC KIDNEY DISEASE

2020 ◽  
Vol 115 (1) ◽  
pp. 18-26
Author(s):  
Anna Petrova ◽  
Olena Karpenko
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Hemodialysis Patients ◽  
Laboratory Studies ◽  
Healthy Individuals ◽  
Age Dependent ◽  
Salivary Melatonin ◽  
The Relationship

The study analyzed the prevalence of hypertension and impaired melatonin-forming function of the epiphysis in patients with stage 5 chronic kidney disease treated with hemodialysis. The relationship between epiphysis dysfunction and hypertension has been identified. 130 persons (50% of men) undergoing permanent hemodialysis treatment were examined. Controls were 20 healthy individuals. The determination of daytime and nighttime levels of melatonin in saliva and clinical and laboratory studies. As a result of the study it was found that for patients with stage 5 chronic kidney disease undergoing treatment, there is a frequent violation of melatonin-forming function of the pineal gland (84.6%) and hypertension (78%). In hemodialysis patients, blood pressure increases are age-dependent and are determined with salivary melatonin levels.

scholarly journals Experimental determination of the temperature dependence of oxygen-isotope fractionation between water and chitinous head capsules of chironomid larvae

2021 ◽  
Author(s):  
Alex Lombino ◽  
Tim Atkinson ◽  
Stephen J. Brooks ◽  
Darren R. Gröcke ◽  
Jonathan Holmes ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Oxygen Isotope ◽  
Oxygen Isotopes ◽  
Isotope Fractionation ◽  
Temperature Dependent ◽  
Oxygen Isotope Fractionation ◽  
Chironomid Larvae ◽  
Increasing Temperature ◽  
The Relationship

AbstractOxygen-isotope values of invertebrate cuticle preserved in lake sediments have been used in palaeoenvironmental reconstructions, generally with the assumption that fractionation of oxygen isotopes between cuticle and water ($$\upalpha_{\text{cuticle}-\text{H}_{2}\text{O}}$$ α cuticle - H 2 O ) is independent of temperature. We cultured chironomid larvae in the laboratory with labelled oxygen-isotope water and across a range of closely controlled temperatures from 5 to 25 °C in order to test the hypothesis that fractionation of oxygen isotopes between chironomid head capsules and water ($$\upalpha_{\text{chironomid}-\text{H}_{2}\text{O}}$$ α chironomid - H 2 O ) is independent of temperature. Results indicate that the hypothesis can be rejected, and that $$\upalpha_{\text{chironomid}-\text{H}_{2}\text{O}}$$ α chironomid - H 2 O decreases with increasing temperature. The scatter in the data suggests that further experiments are needed to verify the relationship. However, these results indicate that temperature-dependence of $$\upalpha_{\text{chironomid}-\text{H}_{2}\text{O}}$$ α chironomid - H 2 O should be considered when chironomid δ18O is used as a paleoenvironmental proxy, especially in cases where data from chironomids are combined with oxygen-isotope values from other materials for which fractionation is temperature dependent, such as calcite, in order to derive reconstructions of past water temperature.

APPLICATION OF THE ATP-BIOLUMINESCENCE METHOD TO ASSESS THE QUALITY OF SANITATION OF MILKING EQUIPMENT

2020 ◽  
Vol 1 (4) ◽  
pp. 468-472
Author(s):  
P.A. Popov ◽  
◽  
D.V. Gruznov ◽  
S.V. Tokarev ◽  
◽  
...  
Keyword(s):  
Dairy Farms ◽  
Laboratory Studies ◽  
Before And After ◽  
Atp Bioluminescence ◽  
Microbial Number ◽  
Proportional Relationship ◽  
The Relationship ◽  
Number Of Bacteria ◽  
Bioluminescence Method

The article presents the results of determining the relationship between the total microbial number and microbial ATP on the surface of milking equipment before and after treatment with neutral anolyte ANK-SUPER. The possibility of using the ATP-bioluminescence method to control the quality of sanitation of milking equipment on dairy farms is shown. Laboratory studies revealed a proportional relationship between the level of bacterial ATP and the number of bacteria on the surface of milking equipment before and after sanitation.

Variations in magnetic properties of Mexican serpentinites and related micro-textures 

2021 ◽  
Author(s):  
Sandra B. Ramírez-García ◽  
Luis M. Alva-Valdivia
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Ultramafic Rocks ◽  
Magnetic Carrier ◽  
Temperature Dependent ◽  
Geochemical Studies ◽  
The Relationship ◽  
Magnetite Formation

<p>Magnetite formation of serpentinized ultramafic rocks leads to variations in the magnetic properties of serpentinites; however, magnetite precipitation is still on debate.</p><p>In this work, we analyzed 60 cores of ultramafic rocks with a variety of serpentinization degrees. These rocks belong to the ultramafic-mafic San Juan de Otates complex in Guanajuato, Mexico. Geochemical studies have been previously conducted, enabling us to compare changes in the magnetic properties against the chemical variations generated by the serpentinization process. By studying the density and magnetic properties such as anisotropy of magnetic susceptibility, hysteresis curves as well as magnetic and temperature-dependent susceptibility and, we were able to identify the relationship between magnetic content and serpentinization degree, the predominant magnetic carrier, and to what extent the magnetite grain size depends on the serpentinization.  Variations in these parameters allowed us to better constrain the temperature at which serpentinization occurred, the generation of other Fe-rich phases such as Fe-brucite and/or Fe-rich serpentine as well as distinctive rock textures formed at different serpentinization degrees.</p>

Modeling the Growth of Salmonella in Cut Red Round Tomatoes as a Function of Temperature

2010 ◽  
Vol 73 (8) ◽  
pp. 1502-1505 ◽  
Author(s):  
WENJING PAN ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Mathematical Model ◽  
Growth Rates ◽  
Low Temperatures ◽  
Safety Concern ◽  
Time Intervals ◽  
Salmonella Serotypes ◽  
Increasing Temperature ◽  
Incubation Temperatures ◽  
Raw Poultry ◽  
The Relationship

Tomato-associated Salmonella outbreaks have recently become a significant food safety concern. Temperature abuse of cut tomatoes may have played a role in some of these outbreaks. The purpose of this study was to develop a mathematical model to describe the growth of Salmonella on cut tomatoes at various temperatures. Four Salmonella serotypes (Typhimurium, Newport, Javiana, and Braenderup) obtained from previous tomato-linked cases of salmonellosis were used in this study. These four serotypes were cultured separately, combined into a cocktail, and inoculated onto whole red round tomatoes and allowed to dry overnight. The tomatoes were then cut into pieces and incubated at a predetermined range of temperatures (10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, and 35°C). Salmonella concentration was measured at specified time intervals to determine the growth curve for Salmonella on cut tomatoes at each temperature. The growth rates were calculated using DMFit and used to build a mathematical model to illustrate the relationship between the growth rates of Salmonella on tomatoes and incubation temperatures from 10 to 35°C. The resulting model compared favorably with a Salmonella growth model for raw poultry developed by our laboratory. The Pathogen Modeling Program underpredicted growth at low temperatures and overpredicted growth at high temperatures. ComBase predicted consistently slower growth rates than were observed in tomatoes but showed parallel increases in growth rate with increasing temperature.

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