Osmoregulation in Trichocorixa verticalis interiores Sailer (Hemiptera, Corixidae) — an inhabitant of Saskatchewan saline lakes, Canada

1975 ◽  
Vol 53 (9) ◽  
pp. 1207-1212 ◽  
Author(s):  
Patricia I. Tones ◽  
U. T. Hammer
Keyword(s):  
Saline Lakes ◽  
Freezing Point ◽  
Saline Water ◽  
Adult Population ◽  
Ionic Composition ◽  
Tolerance Limit ◽  
Freezing Point Depression ◽  
Wide Range ◽  
The Mean

Results of freezing point depression determinations of haemolymph show that first instars, third instars, and adults of Trichocorixa verticalis interiores have well-developed powers of osmoregulation and can hyporegulate in saline water. This species can osmoregulate equally well at 13, 20, and 25 °C but the mean tolerance limit decreases as the temperature increases. T. verticalis interiores is also tolerant to changes in ionic composition. The osmoregulation of this species is similar to that of Sigara stagnalis rather than most Corixidae which are unable to hyporegulate. T. verticalis interiores was collected quantitatively from six athalassic saline lakes which were selected to represent a wide range of salinities. The maximum adult population and conductivity and ionic composition of the water are reported for each lake.

287. The freezing-point of milk. I. The freezing-point and solids-not-fat content of the milk of individual cows throughout a period of lactation

1941 ◽  
Vol 12 (3) ◽  
pp. 315-321 ◽  
Author(s):  
R. Aschaffenburg ◽  
P. L. Temple
Keyword(s):  
Freezing Point ◽  
Extreme Case ◽  
Fat Content ◽  
The State ◽  
Freezing Point Depression ◽  
The Mean ◽  
Time Of Year

The results of regular determinations of the freezing-point and solids-not-fat content of the milk of three Shorthorn cows over a period of more than six months are reported.The known constancy of the freezing-point depression was confirmed, the Δ values deviating generally by less than 2% and, in the most extreme case, by no more than 3·5% from the mean of 0·546 ± 0·002° C. No evidence was found of any influence of the state of lactation on the freezing-point depression, but a slight but definite decrease persisting for some weeks occurred at the time of year at which ample supplies of spring pasture became available to the animals.

Osmoregulation in Ligia Oceanica and Idotea Granulosa

1963 ◽  
Vol 40 (2) ◽  
pp. 381-392
Author(s):  
MARY E. TODD
Keyword(s):  
Blood Concentration ◽  
Sea Water ◽  
Freezing Point ◽  
Freezing Point Depression ◽  
External Concentration ◽  
Osmotic Concentration ◽  
Test Range ◽  
The Mean ◽  
The Difference ◽  
Idotea Granulosa

1. The osmoregulatory response of Ligia oceanica and Idotea granulosa to the range of the experimental variables was similar. They were both hyperosmotic relative to the medium and the difference between internal and external concentration increased as the salinity of the medium decreased. 2. In 100% sea water the osmotic concentration of the blood of Ligia oceanica was markedly above that of the medium, whereas in Idotea granulosa the blood was only marginally hyperosmotic. 3. In Ligia oceanica the blood concentration changed little in 100 and 75% sea water, but dropped significantly between 75 and 50% sea water, whereas blood concentration in Idotea granulosa dropped significantly throughout the test range of salinities. 4. The more efficient osmoregulation of Ligia oceanica in 25% sea water is reflected in the mean freezing-point depression of the blood, Δi = 1.65, compared with Δi = 0.90 in Idotea granulosa. 5. In both species the osmotic concentration of the blood was influenced by season, by temperature and by a temperature-salinity interaction. 6. Neither size nor sex of the animal influenced osmotic concentration of the blood.

The influence of salinity on the cuticular permeability of Cenocorixa bifida hungerfordi Lansbury (Hemiptera: Corixidae)

1981 ◽  
Vol 59 (8) ◽  
pp. 1505-1509 ◽  
Author(s):  
S. G. Cannings
Keyword(s):  
Saline Lakes ◽  
Saline Water ◽  
Surface Conductivity ◽  
Ion Regulation ◽  
Low Salinity ◽  
Low Salinity Water ◽  
Wide Range ◽  
Cuticular Permeability ◽  
Salinity Water ◽  
Over Time

The cuticular permeabilities of individual Cenocorixa bifida hungerfordi Lansbury collected over a wide range of salinities were determined. Corixids from low salinity water (0–2000 μmhos∙cm−1 surface conductivity at 25 °C) exhibited low cuticular permeability, whereas those from moderately saline water bodies (7000 – 11 000 μmhos∙cm−1) were much more permeable. However, at higher salinities cuticular permeability was again low; corixids from a lake with a surface conductivity of 16 000 μmhos∙cm−1 (approximately half that of seawater) had cuticular permeabilities comparable with those of corixids from freshwater lakes. This phenomenon was shown to be acclimatory, since permeability decreased over time when corixids from moderately saline lakes were placed into distilled water. The biological reasons for these results are not clear, but it appears that cuticular permeability of C. bifida increases as problems of ion regulation diminish, and then begins to decrease, seemingly at the salinity at which it becomes difficult for the corixid to maintain a constant haemolymph osmotic pressure. The biological implications of this phenomenon are discussed.

scholarly journals Activity-measurement by the partition method.—I

1924 ◽  
Vol 106 (737) ◽  
pp. 243-250 ◽  
Keyword(s):  
Aqueous Solution ◽  
Electrostatic Potential ◽  
Special Interest ◽  
Freezing Point ◽  
Activity Measurement ◽  
Freezing Point Depression ◽  
Concentration Cell ◽  
Low Concentrations ◽  
The Mean ◽  
Partition Method

In the light of Milner’s calculation of the mean electrostatic potential in chaos of ions, activity-measurement is of special interest at low concentrations aqueous, and still lower concentrations in non-aqueous solution, owing to the simple and peculiar dilution law which the theory predicts for such consentrations. The methods which have chiefly been relied on for such data—that of the Freezing-point depression and that of the concentration cell-—tend to lose recision at low concentrations, owing, in the former, to the smallness of the depression measured, and in the latter, to polarisation effects.

scholarly journals Species of freshwater invertebrates that are sensitive to one saline water are mostly sensitive to another saline water but an exception exists

2018 ◽  
Vol 374 (1764) ◽  
pp. 20180003 ◽  
Author(s):  
Kasey A. Hills ◽  
Ross V. Hyne ◽  
Ben J. Kefford
Keyword(s):  
Major Ions ◽  
Saline Water ◽  
Tap Water ◽  
Ionic Composition ◽  
Relative Sensitivity ◽  
Coal Bed ◽  
Small Subset ◽  
Freshwater Invertebrates ◽  
Elevated Salinity ◽  
Wide Range

Coal mining and extraction of methane from coal beds generate effluent with elevated salinity or major ion concentrations. If discharged to freshwater systems, these effluents may have adverse environmental effects. There is a growing body of work on freshwater invertebrates that indicates variation in the proportion of major ions can be more important than salinity when determining toxicity. However, it is not known if saline toxicity in a subset of species is representative of toxicity across all freshwater invertebrates. If patterns derived from a subset of species are representative of all freshwater invertebrates, then we would expect a correlation in the relative sensitivity of these species to multiple saline waters. Here, we determine if there is a correlation between the acute (96 h) lethal toxicity in freshwater invertebrates to synthetic marine salts (SMS) and sodium bicarbonate (NaHCO 3 ) added to dechlorinated Sydney tap water. NaHCO 3 is a major component of many coal bed effluents. However, most salinization in Australia exhibits ionic composition similar to seawater, which has very little HCO 3 − . Across all eight species tested, NaHCO 3 was 2–50 times more toxic than SMS. We also observed strong correlations in the acute toxicity of seven of the tested species to SMS and NaHCO 3 . The strongest relationship (LC50 r 2 = 0.906) was dependent on the exclusion of one species, Paratya australiensis (Decopoda: Atyidae), which was the most sensitive species tested to NaHCO 3 , but the second-most tolerant of SMS. We conclude that differences in the toxicity of different proportions of major ions can be similar across a wide range of species. Therefore, a small subset of the invertebrate community can be representative of the whole. However, there are some species, which based on the species tested in the current study appear to be a minority, that respond differently to saline effluent and need to be considered separately. We discuss the implications of this study for the management of saline coal bed waters. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects'.

scholarly journals Modeling interfacial liquid layers on environmental ices

2011 ◽  
Vol 11 (18) ◽  
pp. 9971-9982 ◽  
Author(s):  
M. H. Kuo ◽  
S. G. Moussa ◽  
V. F. McNeill
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Low Temperatures ◽  
Freezing Point ◽  
Triple Junctions ◽  
Ice Crystal ◽  
Freezing Point Depression ◽  
Chemical Interactions ◽  
Interfacial Layers ◽  
Wide Range

Abstract. Interfacial layers on ice significantly influence air-ice chemical interactions. In solute-containing aqueous systems, a liquid brine may form upon freezing due to the exclusion of impurities from the ice crystal lattice coupled with freezing point depression in the concentrated brine. The brine may be segregated to the air-ice interface where it creates a surface layer, in micropockets, or at grain boundaries or triple junctions. We present a model for brines and their associated liquid layers in environmental ice systems that is valid over a wide range of temperatures and solute concentrations. The model is derived from fundamental equlibrium thermodynamics and takes into account nonideal solution behavior in the brine, partitioning of the solute into the ice matrix, and equilibration between the brine and the gas phase for volatile solutes. We find that these phenomena are important to consider when modeling brines in environmental ices, especially at low temperatures. We demonstrate its application for environmentally important volatile and nonvolatile solutes including NaCl, HCl, and HNO3. The model is compared to existing models and experimental data from literature where available. We also identify environmentally relevant regimes where brine is not predicted to exist, but the QLL may significantly impact air-ice chemical interactions. This model can be used to improve the representation of air-ice chemical interactions in polar atmospheric chemistry models.

A Comparison of Physiological Demand between Self-Propelled and Motorized Treadmill Exercise

2018 ◽  
Vol 7 (4) ◽  
pp. 13-21
Author(s):  
Todd Backes ◽  
Charlene Takacs
Keyword(s):  
Respiratory Exchange Ratio ◽  
Treadmill Exercise ◽  
Cardiopulmonary Exercise Testing ◽  
Mean Value ◽  
The Self ◽  
Mixing Chamber ◽  
Wide Range ◽  
The Subject ◽  
The Mean ◽  
Computer Controlled

There are a wide range of options for individuals to choose from in order to engage in aerobic exercise; from outdoor running to computer controlled and self-propelled treadmills. Recently, self-propelled treadmills have increased in popularity and provide an alternative to a motorized treadmill. Twenty subjects (10 men, 10 women) ranging in age from 19-23 with a mean of 20.4 ± 0.8 SD were participants in this study. The subjects visited the laboratory on three occasions. The purpose of the first visit was to familiarize the subject with the self-propelled treadmill (Woodway Curve 3.0). The second visit, subjects were instructed to run on the self-propelled treadmill for 3km at a self-determined pace. Speed data were collected directly from the self-propelled treadmill. The third visit used speed data collected during the self-propelled treadmill run to create an identically paced 3km run for the subjects to perform on a motorized treadmill (COSMED T150). During both the second and third visit, oxygen consumption (VO2) and respiratory exchange ratio (R) data were collected with COSMED’s Quark cardiopulmonary exercise testing (CPET) metabolic mixing chamber system. The VO2 mean value for the self-propelled treadmill (44.90 ± 1.65 SE ml/kg/min) was significantly greater than the motorized treadmill (34.38 ± 1.39 SE ml/kg/min). The mean R value for the self-propelled treadmill (0.91 ± 0.01 SE) was significantly greater than the motorized treadmill (0.86 ± 0.01 SE). Our study demonstrated that a 3km run on a self-propelled treadmill does elicit a greater physiological response than a 3km run at on a standard motorized treadmill. Self-propelled treadmills provide a mode of exercise that offers increased training loads and should be considered as an alternative to motorized treadmills.

The way of value of Correlation of genomic DNA microsatellite loci and live weight of Chukchi reindeer

2020 ◽  
pp. 27-32
Author(s):  
V. Dodokhov ◽  
N. Pavlova ◽  
T. Rumyantseva ◽  
L. Kalashnikova
Keyword(s):  
Microsatellite Markers ◽  
Agricultural Production ◽  
Live Weight ◽  
Biodiversity Loss ◽  
Tribal Community ◽  
High Germination ◽  
Wide Range ◽  
The Mean ◽  
High Level ◽  
Dna Microsatellite

The article presents the genetic characteristic of the Chukchi reindeer breed. The object of the study was of the Chukchi reindeer. In recent years, the number of reindeer of the Chukchi breed has declined sharply. Reduced reindeer numbers could lead to biodiversity loss. The Chukchi breed of deer has good meat qualities, has high germination viability and is adapted in adverse tundra conditions of Yakutia. Herding of the Chukchi breed of deer in Yakutia are engaged only in the Nizhnekolymsky district. There are four generic communities and the largest of which is the agricultural production cooperative of nomadic tribal community «Turvaurgin», which was chosen to assess the genetic processes of breed using microsatellite markers: Rt6, BMS1788, Rt 30, Rt1, Rt9, FCB193, Rt7, BMS745, C 143, Rt24, OheQ, C217, C32, NVHRT16, T40, C276. It was found that microsatellite markers have a wide range of alleles and generally have a high informative value for identifying of genetic differences between animals and groups of animal. The number of identified alleles is one of the indicators of the genetic diversity of the population. The total number of detected alleles was 127. The Chukchi breed of deer is characterized by a high level of heterozygosity, and the random crossing system prevails over inbreeding in the population. On average, there were 7.9 alleles (Na) per locus, and the mean number of effective alleles (Ne) was 4.1. The index of fixation averaged 0.001. The polymorphism index (PIC) ranged from 0.217 to 0.946, with an average of 0.695.

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