Delayed Inoculative Freezing of Insects

1963 ◽  
Vol 95 (11) ◽  
pp. 1190-1202 ◽  
Author(s):  
R. W. Salt
Keyword(s):  
Fine Structure ◽  
Vapor Pressure ◽  
Body Fluid ◽  
Rate Increase ◽  
Chemical Potential ◽  
Structural Characteristics ◽  
Detergent Solution ◽  
Vapor Pressure Difference ◽  
Ice Surface ◽  
Inoculative Freezing

AbstractInoculative freezing of insects is distinguished from nucleative freezing and is treated from the standpoint of the delays observed in freezing. On the assumption that the fine structure of the cuticle regulates the penetration or growth of external ice into the insect's body, the cuticle was experimentally altered by soaking, boiling, and immersion in strong detergent solution. Soaking was of doubtful effectiveness, whereas boiling and detergent hastened inoculation, Detergent also caused many insects to freeze when the contact water froze, with no delay. Rate of inoculation of untreated larvae was directly proportional to the area in contact with ice, and inversely proportional to temperature down to −10 °C. No further rate increase took place down to −15 °C, possibly because the vapor pressure difference between ice and supercooled body fluid does not change appreciably in this temperature range. Larvae froze more rapidly when they had already been frozen and thawed once or twice. No relation between inoculation rate and rate of water loss in a dry atmosphere could be established.The freezing of water in extremely small spaces is discussed and related to the process of inoculative freezing. Probable pathways of ice growth through the cuticle are considered in relation to known structural characteristics and the results of the present experiments. Two hypotheses are proposed to account for the observed delays in freezing, but neither is wholly satisfactory. The first postulates that the outer extremities of the pathways, through the epicuticle, are hydrophobic and contain air which temporarily separates contact moisture from pore liquids. After freezing of the contact moisture a vapor pressure differential results in a net flow of vapor outwards, the vapor freezing on the ice and building inwards until the ice front touches liquid in a space large enough to allow freezing. This hypothesis assumes the existence of at least one pathway large enough to support ice penetration without hindrance caused by restricted size. The second hypothesis assumes that no such unrestricted pathways are present, all being inadequate in size. Differences in chemical potential between ice and liquid cause pore liquids to move outwards to the contacting ice surface and accrete on its

Partially miscible liquid systems: The density, change of volume on mixing, vapor pressure, surface tension, and viscosity in the system: aniline–hexane

1968 ◽  
Vol 46 (14) ◽  
pp. 2399-2407 ◽  
Author(s):  
A. N. Campbell ◽  
E. M. Kartzmark ◽  
S. C. Anand ◽  
Y. Cheng ◽  
H. P. Dzikowski ◽  
...  
Keyword(s):  
Surface Tension ◽  
Vapor Pressure ◽  
Chemical Potential ◽  
Density Change ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Pressure Surface ◽  
Anomalous Viscosity ◽  
Tension Properties ◽  
Liquid Systems

The following properties have been investigated experimentally: density, change of volume on mixing, vapor pressure, surface tension, and viscosity, at temperatures above and below the critical solution temperature. The question at issue is: How does the chemical potential, or any property dependent on chemical potential, change, at constant temperature, over a range of composition, just above the critical solution temperature? In the present case, the vapor pressure and surface tension, properties directly dependent on chemical potential, are constant within the range of experimental accuracy (which, however, may not be sufficient) over a range of concentration. The viscosity is complicated by the occurrence of anomalous viscosity. The change of volume on mixing is negative, and this is usually associated with compound formation. In all other systems investigated by us, except the system triethylamine–water, ΔV is positive. We have shown elsewhere, however, that a very stable chemical compound is formed between water and triethylamine.

Setting Realistic Design Indoor Conditions for Residential Buildings by Vapor Pressure Difference

2009 ◽  
Vol 6 (9) ◽  
pp. 102052 ◽  
Author(s):  
Patrick Roppel ◽  
Mark Lawton ◽  
William C. Brown ◽  
Phalguni Mukhopadhyaya ◽  
Mavinkal K. Kumaran ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Pressure Difference ◽  
Residential Buildings ◽  
Vapor Pressure Difference ◽  
Indoor Conditions

Photosynthesis in an open field for exotic versus native vines of the southeastern United States

1989 ◽  
Vol 67 (2) ◽  
pp. 443-446 ◽  
Author(s):  
Gregory A. Carter ◽  
Alan H. Teramura ◽  
Irwin N. Forseth
Keyword(s):  
Vapor Pressure ◽  
Pressure Difference ◽  
Native Species ◽  
Leaf Gas Exchange ◽  
Water Vapor Pressure ◽  
High Irradiance ◽  
Pueraria Lobata ◽  
Vapor Pressure Difference ◽  
High Vapor ◽  
Parthenocissus Quinquefolia

The potential importance of leaf gas exchange to the prolific growth characteristics of the exotic vines Pueraria lobata and Lonicera japonica versus the native vines Rhus radicans, Parthenocissus quinquefolia, Vitis vulpina, and Clematis virginiana was evaluated. Under high irradiance and low leaf-air water vapor pressure difference, photosynthesis was similar (23 – 27 μmol∙m−2∙s−1) among species with the exception of R. radicans (16 μmol∙m−2∙s−1). Conductance and transpiration were greater in Pueraria lobata than in the other species. When the leaf-air vapor pressure difference was high (4.0 kPa) photosynthesis in the exotic vines decreased more than in several of the native species. Photosynthesis in L. japonica and Parthenocissus quinquefolia, and to a lesser extent in Pueraria lobata, was reduced by high vapor pressure differences even though internal CO2 partial pressures remained relatively high, suggesting a nonstomatal reduction of photosynthetic capacity. Thus, the highly prolific growth typical of the exotic vines may not be attributable to greater steady-state photosynthesis.

Osmosis: Characteristics of Liquid at an Interface

2006 ◽  
Author(s):  
Larry D. Howlett
Keyword(s):  
Kinetic Energy ◽  
Kinetic Theory ◽  
Vapor Pressure ◽  
Pressure Difference ◽  
Total Kinetic Energy ◽  
Universal Model ◽  
Vapor Pressure Difference ◽  
Water Ice ◽  
Speed Distribution

Many explanations for the movement of water across a membrane have been presented. One idea proposes that osmosis is the movement of water in response to a vapor pressure difference. It is difficult to accept this model for osmosis without a good understanding of the existence of a vapor in a liquid. We propose a model for a vapor in a liquid. The model is based upon the kinetic theory of gas and Maxwell's predicted speed distribution. Since vapor pressure and total kinetic energy are both expressions of the energy of a gas, we compare the model to published values of vapor pressure for water, ice, and several other liquids. Based upon this limited comparison, it appears that this model may be a universal model for the continuous existence of a vapor in a liquid or a solid.

Fine Structure of Nerve Cells in the Brain of the House Fly, Musca Domestica (Diptera)

1971 ◽  
Vol 29 ◽  
pp. 274-275
Author(s):  
Venita F. Allison ◽  
Suraj P. Sharma ◽  
R. S. Sohal
Keyword(s):  
Fine Structure ◽  
Musca Domestica ◽  
Structural Characteristics ◽  
Cell Types ◽  
Small Population ◽  
House Fly ◽  
Nerve Cells ◽  
Type I ◽  
Structural Level ◽  
The Brain

Because of its comparative structural simplicity insect central nervous system has been frequently used for basic neurological studies. However, relatively little is known regarding the cytological organization of the different neuronal types, especially at the fine structural level. The precise localization and identification of particular cell types within the brain would be useful in correlating structural characteristics of neurons with their integrative functional role. The present study reports the fine structure of three different types of nerve cells within the anterior protocerebral region of the brain of the adult male house fly, Musca domestica.Type I Neuron (Figure 1): Examination of the anterior lateral region of the protocerebrum reveals a small population of uni-polar neurons further characterized by perikarya with a paucity of cytoplasm and proportionately large dense nuclei. The cytoplasm contains poorly developed endoplasmic reticulum, an abundance of ribosomes and a few ovoid to rounded mitochondria with shelf-like cristae. Small Golgi regions and dense inclusion bodies are seen in certain planes of section.

Photosynthesis and transpiration in large forest-grown Douglas-fir: diurnal variation

1981 ◽  
Vol 59 (3) ◽  
pp. 349-356 ◽  
Author(s):  
Jerry W. Leverenz
Keyword(s):  
Stomatal Conductance ◽  
Vapor Pressure ◽  
Diurnal Variation ◽  
Pressure Difference ◽  
Intercellular Space ◽  
Net Photosynthesis ◽  
Douglas Fir ◽  
Leaf Temperature ◽  
Photon Flux ◽  
Vapor Pressure Difference

Net photosynthesis, transpiration, and stomatal conductance of terminal shoots of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were measured using an open gas exchange system. Correlations between these physiological parameters and environmental variables on an overcast day, a cool partly sunny day, and a day of high temperature and leaf–air vapor pressure difference are presented. Diurnal variation in shoot water potential and intercellular space CO2 concentration had little effect on the physiological parameters. Leaf–air vapor pressure difference and (or) leaf temperature had considerable influence on days of high temperatures. Net photosynthetic rate was strongly correlated with photon flux density on completely overcast days.Stomatal conductance exerted little control on diurnal variation of net photosynthetic rates on overcast days because stomatal conductance saturated at lower photon flux densities than net photosynthesis. When net photosynthesis was light saturated parallel responses of stomatal and residual conductances to vapor pressure difference and (or) leaf temperature occurred. Intercellular space CO2 concentration remained fairly constant when net photosynthesis was light saturated.

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