Seasonal trends and effects of temperature and rainfall on stem electrical capacitance of spruce and fir trees

1990 ◽  
Vol 20 (7) ◽  
pp. 970-977 ◽  
Author(s):  
Timothy M. Lekas ◽  
R. Glenn MacDougall ◽  
David A. MacLean ◽  
Robert G. Thompson
Keyword(s):  
Black Spruce ◽  
Red Spruce ◽  
Annual Rainfall ◽  
Permanent Plots ◽  
Dry Period ◽  
Seasonal Trends ◽  
Influence Of Water ◽  
Effects Of Temperature ◽  
Relationship Of ◽  
The Relationship

Seasonal trends of stem capacitance were generally similar among balsam fir (Abiesbalsamea (L.) Mill.), white spruce (Piceaglauca (Moench) Voss), red spruce (Picearubens Sarg.), and black spruce (Piceamariana (Mill.) B.S.P.) trees and among plots. In 1987, stem capacitance increased following bud break until early June and then slowly declined until September 8, corresponding to an extended dry period (less than 27% of the annual rainfall of the previous 7 years). Dramatic increases in stem capacitance were observed following 55 mm of rain on September 9, 1987. During autumn of both 1987 and 1988, stem capacitance steadily declined; mean capacitance of trees in seven plots in October and November 1987 was 55–89 and 35–74% of values in June and July 1987, respectively. Diameter at breast height increment of 34 red spruce trees and 190 spruce and fir trees in permanent plots was consistently significantly (p <0.001) related to mean monthly capacitance; the strongest relationships (55–83% of the variability explained) were with mean June or July capacitance. The relationship of stem capacitance with growth of fir and spruce trees was corroborated. In addition, a stronger influence of water relations on capacitance than previously thought was demonstrated.

Effects of temperature on membrane potentials of lobster giant axon

1962 ◽  
Vol 202 (3) ◽  
pp. 491-494 ◽  
Author(s):  
J. C. Dalton ◽  
D. E. Hendrix
Keyword(s):  
Action Potential ◽  
Giant Axon ◽  
Resting Potential ◽  
Initial Increase ◽  
Squid Axon ◽  
Temperature Dependent ◽  
Increase With Increase ◽  
Effects Of Temperature ◽  
Relationship Of ◽  
The Relationship

In the range 2–20 C, the resting potential of the lobster axon shows a greater increase with increase of temperature than can be explained by the Nernst relationship. Action potential also shows an initial increase with temperature, peaks at about 16 C, then decreases. Maximum rates of rise and fall of the action potential increase with temperature increase; duration of the propagated action potential decreases. Afterpotentials in this preparation are in the form of a delayed repolarization; as temperature is increased, the magnitude of the afterpotentials increases, as does the rate of repolarization. These results have been compared with results already available for the squid axon. Differences between the two preparations occur in the relationship of the resting potential, action potential magnitude, and afterpotentials to temperature. It is suggested that these differences may be explained by the presence of a temperature-dependent fraction of the resting potential in the lobster axon which is not present, or is inactive, in the squid axon.

Analysis of the Influence of Water Content on Shanxi Loess CBR and Rebound Module

2014 ◽  
Vol 919-921 ◽  
pp. 820-823
Author(s):  
Xi Rong Wu ◽  
Li Li Zhu
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Resilient Modulus ◽  
Test Methods ◽  
Shanxi Province ◽  
Influence Of Water ◽  
The Times ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

Selection of five typical loess in Shanxi Province, the paper adopt the indoor test methods to prepares the different compaction and different moisture content specimens which were used to test CBR value and rebound module, analyzes the impact of compactness and moisture content on the CBR value and resilient modulus and establishes the relationship of CBR and moisture content. The result shows that the level of moisture content has great impact on CBR value and rebound module. The CBR value is maximal under optimum moisture content and maximum degree of compaction condition. The times of compaction have little effect on the improvement of CBR with increasing water content. The relationship of the soaking CBR,resilient modulus and the moisture content shows a certain regularity.Key words: Loess filler;the CBR;resilient modulus;compactness;moisture content;relationship

Influence of water temperature on heart rate and rectal temperature of swimming rats

1964 ◽  
Vol 207 (5) ◽  
pp. 1073-1076 ◽  
Author(s):  
Mary Ann Baker ◽  
Steven M. Horvath
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Rectal Temperature ◽  
Cold Water ◽  
Submaximal Exercise ◽  
The Body ◽  
Small Animals ◽  
Influence Of Water ◽  
Relationship Of ◽  
The Relationship

The heart rate and rectal temperature of 12 adult male hooded rats were studied during 10-min swims in water of 37, 20, and 42 C. Both the heart rate and the rectal temperature stabilized in water of 37 C, suggesting that swimming in thermoneutral water is a submaximal exercise for rats. In water of 20 C, rectal temperature and heart rate of swimming animals fell exponentially to 28 C and 251 beats/min, respectively. The relationship of heart rate to rectal temperature in these swimming, cooling animals was not different from that reported in the literature for unanesthetized, inactive, hypothermic rats. It appeared that exercise had no effect on the heart rate of rats when the body temperature was dropping. In water of 42 C the rectal temperature rose exponentially to 42.2 C. The heart rate rose to 521 beats/min at the 8th min of swimming and remained stable thereafter. It is suggested that inadequate cardiac output resulting from severe changes in body temperature may be one factor which limits swimming capacity of small animals in hot and cold water.

Effects of temperature and leaf wetness duration on infection of pear leaves by Venturia pirina

2000 ◽  
Vol 51 (1) ◽  
pp. 97 ◽  
Author(s):  
O. N. Villalta ◽  
W. S. Washington ◽  
G. M. Rimmington ◽  
P. A. Taylor
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Leaf Wetness ◽  
Leaf Wetness Duration ◽  
Controlled Conditions ◽  
Pyrus Communis L ◽  
Venturia Pirina ◽  
Effects Of Temperature ◽  
Relationship Of ◽  
The Relationship

The effects of temperature and wetness duration on the infection of pear leaves (Pyrus communis L.) by Venturia pirina were studied by inoculating plants with ascospores and conidia under controlled conditions and in the field. Under controlled inoculations, minimum wetness durations that lead to leaf infections by ascospores were 27, 15, 13, 11, 10, 9, and 9 h at 4, 8, 10, 12, 15, 20, and 25°C, respectively. In parallel inoculations with conidia, the minimum wetness durations that lead to leaf infections were similar to ascospores at temperatures between 12°C and 25°C, but at lower temperatures (4, 8, 10°C), conidia infected leaves only after an additional 2 h of leaf wetness. The relationship between minimum wetness times and temperature was best described using an exponential regression. In field experiments, leaf infection on plants inoculated with ascospores and conidia under various naturally occurring wetness and temperature conditions was in close agreement with those under controlled conditions. Disease severity (percent of leaf area infected) increased with increasing leaf wetness duration at all temperatures. The optimum temperature for infection was 20°C. Analysis of variance with orthogonal polynomial contrasts was used to define the relationship of the angular transformation of disease severity to temperature and leaf wetness duration.

Modelling the relationship of tree-level product value with tree characteristics in black spruce

2006 ◽  
Vol 82 (5) ◽  
pp. 690-699 ◽  
Author(s):  
S Y Zhang ◽  
Y C Lei ◽  
Z H Jiang
Keyword(s):  
Black Spruce ◽  
Tree Height ◽  
Tree Level ◽  
Elasticity Analysis ◽  
Scale Elasticity ◽  
Stem Taper ◽  
Product Value ◽  
Relationship Of ◽  
The Relationship ◽  
Tree Characteristics

The establishment of the relationship between tree-level product value and tree characteristics will allow for predicting the potential value of individual trees and a stand directly using tree characteristics. Using statistical and elasticity analysis methods this study examined the relationship of tree-level product value with selected tree characteristics in black spruce (Picea mariana). The study was based a sample of 139 trees from 48-year-old black spruce plantations grown in Ontario, Canada. The sample trees showed large variation in tree characteristics and tree-level product value. Models were developed and compared on the basis of statistics of the estimated and predicted criteria. Results show that the model, including only tree DBH, tree height and stem taper, is the best in describing the relationship of the tree-level product value with tree characteristics. Furthermore, relationships including input-output and interaction factors in the model were analyzed by calculating the elasticity of production and scale and the cross partial derivative of output with respect to the inputs. The analyses indicate that tree DBH has the largest and positive influence on tree-level product value, followed by tree height; however, stem taper has a negative effect on tree-level product value. When tree DBH, tree height and stem taper each increase by 1%, the quantities of output elasticity show 2.53%, 0.64% and -0.37% changes in the product value, respectively; while the scale elasticity shows a 2.81% increase in tree-level product value with a simultaneous 1% change in tree DBH, tree height and stem taper. Results indicate that the model is suitable for predicting tree-level product value using those tree characteristics from forest inventory and also reflects biological behaviour.Key words: black spruce, regression models, elasticity analysis, product value, tree characteristics

EFFECTS OF TEMPERATURE ON WINTER MOTH PUPAE, OPEROPHTERA BRUMATA (LEPIDOPTERA: GEOMETRIDAE)

1983 ◽  
Vol 115 (3) ◽  
pp. 243-249 ◽  
Author(s):  
N. J. Holliday
Keyword(s):  
Adult Emergence ◽  
Operophtera Brumata ◽  
Winter Moth ◽  
Pupal Period ◽  
Diurnal Temperature ◽  
Temperature Cycles ◽  
Effects Of Temperature ◽  
Relationship Of ◽  
The Relationship

AbstractPupae of winter moth, Operophtera brumata (L.) (Lepidoptera: Geometridae), from southwest England were subjected to nine temperature treatments in the laboratory. The pupal period of about 180 days was unaffected by changes in mean temperatures between 9.5 °C and 16.8 °C. Adult emergence was delayed at a mean temperature of 17.7 °C; no pupae survived at mean temperatures above this. These results are compared with conflicting statements in the literature about the relationship of length of the pupal period with temperature.No pupae died when exposed to temperature cycles of 20°–25 °C in the early part of the pupal period. The same temperatures near the time of adult emergence caused increased mortality. The duration of the pupal period was unaffected by exposure of pupae to 12 h (rather than diurnal) temperature cycles.

scholarly journals Long-Term Study of the Relationship between Precipitation and Aquatic Vegetation Succession in East Taihu Lake, China

Scientifica ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yehui Zhang ◽  
Na Yang ◽  
Jiawei Xu ◽  
Yixing Yin
Keyword(s):  
Water Level ◽  
Aquatic Plants ◽  
Aquatic Vegetation ◽  
Taihu Lake ◽  
Vegetation Succession ◽  
Annual Rainfall ◽  
Dry Period ◽  
Long Term Study ◽  
The Relationship

Based on long-term rainfall measurements (1956–2012), water level records (1956–2006), and aquatic plants field survey data (1960–2014), the relationship between precipitation and aquatic vegetation succession in east Taihu Lake, China, is studied. Neither abrupt changes nor any trends were found in the annual rainfall series in Taihu Lake during the studied period (1956–2012). However, for seasonal variations, statistically significant decreases are found in spring and autumn, while the rainfall in winter exhibits statistically significant increase. No significant trend was obtained in summer. A “dry” period was detected in our studied period (1963/1964~1978/1979). Total annual rainfall was significantly positively correlated to the number of rain-days (r=0.59) and the water level (r=0.84). Our results indicate that the variations of rainfall and water level may have an impact on the aquatic plants in Taihu Lake. The dry period may be not suitable for the growth of the aquatic plants. All aquatic plants in Taihu Lake were dramatically reduced in the dry period, especially for submerged macrophytes and floating-leaf macrophytes. Our results may be helpful for the aquatic restoration in the future.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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