Studies on the environmental physiology of some Australian lizards from arid and semi-arid habitats.

1965 ◽  
Vol 13 (4) ◽  
pp. 563 ◽  
Author(s):  
MR Warburg
Keyword(s):  
High Temperatures ◽  
Water Loss ◽  
Low Temperatures ◽  
The Body ◽  
The Other ◽  
Arid Conditions ◽  
Arid Habitat ◽  
Rate Of Evaporation ◽  
Semi Arid ◽  
Low Rate

The microclimate of an arid habitat was studied at midsummer. Several species of lizards found there, and in semi-arid habitats, were examined. The lizards were: Agamidae; Amphibolurus reticulatus inermis (De Vis), A pictus Peters, A. cristatus Gray, and A. decresii Dumeril & Bibron; Varanidae, Varanus gouldii Gray; Scincidae, Tiliqua melanops Stirling & Ziets. The rate of water loss by evaporation was determined under different combinations of temperature and humidity. Of the lizards studied, A. r. inermis was the only species fully adapted to life in arid conditions. No evidence for evaporative cooling of the body at high temperatures was obtained. It is suggested that this lizard survives in arid habitats mainly because it is able to tolerate long exposures to high temperatures and low humidities, not because it is capable of maintaining low temperatures. The rate at which water is lost by this lizard was remarkably low when compared with the other lizards. The curves of increasing water loss in dry air at 37.5�C (in agamids) may be indicative of their degree of adaptedness. Thus, A. r. inermis has the lowest rate of water loss, followed by A. pictus, A. cristatus, and A. decresii, respectively. The skink, T. melanops, and the goanna, V. gouldii, show a fairly low rate of evaporation at that temperature.

Evolution of water balance in the genusDrosophila

2001 ◽  
Vol 204 (13) ◽  
pp. 2331-2338 ◽  
Author(s):  
Allen G. Gibbs ◽  
Luciano M. Matzkin
Keyword(s):  
Water Balance ◽  
Water Loss ◽  
The Body ◽  
The Other ◽  
Arid Environments ◽  
Physiological Mechanisms ◽  
Dehydration Tolerance ◽  
Cactophilic Drosophila ◽  
Adaptive Mechanisms ◽  
The World

SUMMARYFruit flies of the genus Drosophila have independently invaded deserts around the world on numerous occasions. To understand the physiological mechanisms allowing these small organisms to survive and thrive in arid environments, we performed a phylogenetic analysis of water balance in Drosophila species from different habitats. Desert (cactophilic) species were more resistant to desiccation than mesic ones. This resistance could be accomplished in three ways: by increasing the amount of water in the body, by reducing rates of water loss or by tolerating the loss of a greater percentage of body water (dehydration tolerance). Cactophilic Drosophila lost water less rapidly and appeared to be more tolerant of low water content, although males actually contained less water than their mesic congeners. However, when the phylogenetic relationships between the species were taken into account, greater dehydration tolerance was not correlated with increased desiccation resistance. Therefore, only one of the three expected adaptive mechanisms, lower rates of water loss, has actually evolved in desert Drosophila, and the other apparently adaptive difference between arid and mesic species (increased dehydration tolerance) instead reflects phylogenetic history.

Effect of Sodium Exposure On the Mechanical Properties of Zirconium

CORROSION ◽  
1961 ◽  
Vol 17 (1) ◽  
pp. 31t-34t ◽  
Author(s):  
J. C. BOKROS
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Tensile Properties ◽  
High Temperatures ◽  
Low Temperatures ◽  
Hydrogen Absorption ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Surface Oxide ◽  
The Other

Abstract It was found that surface oxide which developed on zirconium in impure sodium significantly lowered the fatigue life at elevated temperatures. Hydrogen absorption, on the other hand, had little effect on the fatigue life at elevated temperatures but lowered the fatigue life at room temperature. Also, critical recrystallization which occurred above 950 F in zirconium (a phenomenon unrelated to the presence of sodium) reduced the fatigue life at elevated as well as low temperatures. The effects attributable to sodium (i.e., the formation of surface oxide and absorption of reasonable amounts of hydrogen), did not significantly alter the tensile properties of zirconium at high temperatures. 6.3.20, 4.7, 3.5.8, 3.2.3

scholarly journals Evapotranspiration of sorghum from the energy balance by METRIC and STSEB

2020 ◽  
Vol 24 (1) ◽  
pp. 24-30
Author(s):  
João G. A. Lima ◽  
Juan M. Sánchez ◽  
José G. Piqueras ◽  
José Espínola Sobrinho ◽  
Paula C. Viana ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Energy Balance ◽  
Surface Energy Balance ◽  
Irrigation Management ◽  
The Other ◽  
Accurate Estimation ◽  
Actual Surface ◽  
Arid Conditions ◽  
Source Models ◽  
Semi Arid

ABSTRACT The estimate of the actual surface evapotranspiration (ET) contributes to quantifying the water needs of crops. An alternative to the use of lysimeter for an accurate estimation of water needs, which has proved to be of great value in recent years, is the use of remote sensing combined with models based on surface energy balance. There is wide variety of models that can be classified into two types: one-source models, such as the Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC) algorithm, or two-source models, such as the Simplified Two-Source Energy Balance (STSEB). The objective of this study was to analyze how METRIC and STSEB can be used to estimate ET, in comparison with the lysimeter data, for the different stages of development of the sorghum crop in Apodi, RN, Brazil. The accuracy of both models in the daily ET estimation for the semi-arid conditions of the experiment, with RMSE values of 0.8 and of 0.7 mm d-1 through METRIC and STSEB, respectively, is considered acceptable for irrigation management purposes. The errors obtained with METRIC at an instantaneous scale were 60, 50, 130 and 5 W m-2 for Rn, LE, H and G, respectively, on the other hand, using STSEB these errors were of 40, 70, 120 and 21 W m-2 for Rn, LE, H and G, respectively. The METRIC and STSEB models are very similar when it comes to providing information on water needs of the sorghum.

scholarly journals Water Status and Yield Response to Deficit Irrigation and Fertilization of Three Olive Oil Cultivars under the Semi-Arid Conditions of Tunisia

2019 ◽  
Vol 11 (17) ◽  
pp. 4812 ◽  
Author(s):  
Mouna Aïachi Mezghani ◽  
Amel Mguidiche ◽  
Faiza Allouche Khebour ◽  
Imen Zouari ◽  
Faouzi Attia ◽  
...  
Keyword(s):  
Water Use ◽  
Water Status ◽  
Leaf Water ◽  
The Other ◽  
Control Treatment ◽  
Leaf Water Content ◽  
Arid Conditions ◽  
Water Potentials ◽  
Use Efficiency ◽  
Semi Arid

Sustainability of olive production is possible by adopting the modern techniques of irrigation and fertilization. In Tunisia, olive trees are usually cultivated in poor soils, under semi-arid conditions characterized by water scarcity. This study investigated the effects of different water supply and fertilization on leaf water status and crop yield of three different olive oil varieties cultivated in central Tunisia, during four experimental seasons (2014–2017). Three treatments were examined: trees conducted under rainfed conditions (TRF), which represented the control treatment, trees irrigated with 50% ETc (T50) and, finally, trees irrigated with 50% ETc and with additional fertilization (T50F). Leaf water content and potential, yield and water use efficiency have been monitored on three different varieties, Chetoui, Chemlali, and Koroneiki, which are quite typical in the considered region. For all the growing seasons, midday leaf water potentials were measured from April to September. Midday leaf water potentials (MLWP) were generally higher for the two irrigated treatments (T50 and T50F) than for non-irrigated trees (TRF). As the season proceeded, MLWPs tended to decrease during summer for all the treatments and varieties. The lowest values were observed for the non-irrigated trees, varying between −3.25 MPa to −4.75 MPa. Relative leaf water content followed the same trends of midday leaf water potentials. Chetoui showed the lowest yield, which did not exceed 1530 Kg/(ha year), even for irrigated and fertilized trees. On the other hand, the yields of Chemlali and Koroneiki, cumulated in the four years, reached the maximum value of about 20 tons/ha. For these two varieties, the cumulated yield obtained in the control treatment (TRF) resulted significantly lower than the corresponding of the other two treatments (T50 and T50F). The highest irrigation water use efficiency (WUE) was estimated for Chemlali (T50) and (TRF). WUE was equal to 1.22 Kg/m3 for Koroneiki under fertigated treatment (T50F). Application of the only water supply (50% ETc) or associated with fertilizer improved the tree water status and increased the productivity of Chemlali and Koroneiki varieties.

Studies on the water economy of some Australian frogs.

1965 ◽  
Vol 13 (2) ◽  
pp. 317 ◽  
Author(s):  
MR Warburg
Keyword(s):  
High Temperatures ◽  
Water Uptake ◽  
Water Loss ◽  
Vapour Pressure ◽  
Arid Regions ◽  
Vapour Pressure Deficit ◽  
Evaporative Water ◽  
Dry Air ◽  
Reduced Water ◽  
Semi Arid

The rate of evaporative water loss of several species of frog found in Australia and their ability to survive at high temperatures were studied at various temperatures in both dry and in humid air, and at constant vapour pressure deficit. The species studied were: Bufonidae, Bufo marinus (L.); Leptodactylidae, Crinia signifera Girard, Pseudophryne bibroni Gunther, Limnodynastes tasmaniensis Gunther, L. dorsalis (Gray), L. ornatus (Gray), Neobatrachus pictus Peters, N. centralis (Parker); Hylidae, Hyla ewingi (Dumeril & Bibron) and H. rubella Gray. To a certain extent, the trend for increased adaptation to terrestrial conditions follows the trend for reduced water loss. The rate of water uptake after dehydration is greatest in the burrowing frogs inhabiting arid and semi-arid regions. Survival at high temperatures in dry air was found to be a good criterion for judging the degree of adaptation of these frogs to life in arid regions.

On the Behaviour of Wireworms of the Genus Agriotes Esch. (Coleoptera, Elateridae)

1943 ◽  
Vol 20 (1) ◽  
pp. 43-53
Author(s):  
A. D. LEES
Keyword(s):  
Water Loss ◽  
The Other ◽  
Sudden Increase ◽  
Great Activity ◽  
Moist Air ◽  
Steep Gradient ◽  
Dry Air ◽  
Constant Rate ◽  
Rate Of Evaporation ◽  
Humidity Range

1. The general humidity behaviour, the humidity receptors and the orientation mechanisms have been studied in the larvae of Agriotes. 2. Wireworms avoid dry air, the intensity of avoidance being greatest when the alternatives are close to saturation . Within this humidity range a difference of 7.5 % R.H. in the alternative chamber (at 17 ° C.) is sufficient to ensure the successful avoidance of the lower humidity by nearly every individual, while statistically significant reactions are obtained with differences as small as 0.5 % R.H. At lower ranges of humidity the same differences yield progressively less intense reactions; at low humidities the response is entirely eliminated. 3. The intensity of the reaction is in better accord with the humidity differences when these are expressed as saturation deficiencies rather than as relative humidities. This suggests that the reaction is initiated by the evaporation of water (‘evapori-meter’ receptor) and not by the operation of receptors which function hygrometrically (‘hygrometer’ receptors). 4. The humidity ‘receptors’ lie on the head. Amputation experiments indicate that the relevant sites of evaporation are distributed between the antennae, maxillary and labial palps; the structure of these appendages is compatible with such a function;- on the other hand, sensilla which might conceivably have a hygroscopic function are absent. 5. Orientation is achieved by the operation of two mechanisms. First, larvae are more active in dry than in moist air (low hygro-kinesis); secondly, larvae show a directed response to low humidities (klinotaxis); this is displayed as a powerful backward recoil if the wireworm crosses a steep gradient from moist into dry air. No tropo-tactic component is involved. The failure of the reaction at low humidities is explained by the great activity of the larvae which interferes with the operation of the klino-tactic mechanism. It is suggested that the kinesis is maintained by a relatively constant rate of water loss from the head appendages, while the klino-taxis is initiated by any sudden increase in the rate of evaporation. 6. The behaviour can readily be correlated with the humidity conditions prevailing in the soil; the necessity for such a sensitive response is possibly dictated by the permeability of the cuticle which renders wireworms peculiarly liable to water loss in unsaturated atmospheres.

The Body Temperature of Woodlice

1951 ◽  
Vol 28 (3) ◽  
pp. 271-280
Author(s):  
E. B. EDNEY
Keyword(s):  
Body Temperature ◽  
Water Vapour ◽  
High Temperatures ◽  
Air Temperature ◽  
Water Loss ◽  
Evaporation Rate ◽  
The Body ◽  
Steady Temperature ◽  
Dry Air ◽  
Temperature Depression

1. Measurements by means of thermocouples, accurate to 0.1°C., were made of the body temperature of the woodlice Armadillidium, Porcellio, Oniscus and Ligia, and of the cockroach Blatta, both alive and dead, in a stream of saturated or dry air at both 20 and 37°C. 2. No difference in temperature depression was found between living and dead woodlice, and in all the animals used there was, after equilibration, no difference greater than 0.1°C. between the air temperature and body temperature if the air were saturated with water vapour. 3. In dry air, the body temperature of all the animals except Ligia settled down after at most 25 min. to a steady temperature which was lower than that of the surrounding air. The body temperature of Ligia continued to rise slowly for at least 2 hr., though remaining well below that of the environment. 4. After 30 min. in dry air at 20 and 37°C. respectively, mean temperature depressions (of at least three readings at each temperature for each species) were, in degrees centigrade: Ligia, 2.6 and 6.8; Oniscus, 1.5 and 2.7; Parcellio, 0.4 and 1.3; Armadillidium, 0.5 and 1.8; and the cockroach Blatta, 0.7 and 2.4. The order of the species in this respect is substantially the same as their order in respect of evaporation rate, which was established previously. 5. Certain anomalies which appear when these figures are compared with previously established figures for insects are probably the result of differences in permeability of the integument and in the site of water loss. The ability to evaporate water rapidly, and thus to cool the body, may be of survival value when woodlice are exposed to high temperatures for short periods, particularly in littoral forms which may well have been intermediate in the evolution of terricolous from maricolous isopods.

High Heels sebagai Agensi bagi Tubuh Wanita

2020 ◽  
Vol 5 (2) ◽  
pp. 196
Author(s):  
Sunandar Macpal ◽  
Fathianabilla Azhar
Keyword(s):  
Body Image ◽  
Literature Review ◽  
The Body ◽  
The Other ◽  
Body Image Disturbance ◽  
Other Hand ◽  
High Heels ◽  
Experience Pain ◽  
Woman's Body

The aims of this paper is to explain the use of high heels as an agency for a woman's body. Agency context refers to pain in the body but pain is perceived as something positive. In this paper, the method used is a literature review by reviewing writings related to the use of high heels. The findings in this paper that women experience body image disturbance or anxiety because they feel themselves are not beautiful or not attractive. The use of high heels, makes women more attractive and more confident, on the other hand the use of high heels actually makes women feel pain and discomfort. However, for the achievement of beauty standards, women voluntarily allow their bodies to experience pain. However, the agency's willingness to beauty standards here is meaningless without filtering and directly accepted. Instead women keep negotiating with themselves so as to make a decision why use high heels.

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