Hypothalamic Temperature in the Cat during Feeding and Sleep

Anterior hypothalamic temperature is reported for the unanesthetized cat resting at an air temperature of 22 degrees to 25 degrees C during the ingestion of cold or warm liquids, and during sleep. Drinking cold (5 degrees C) milk resulted in an immediate depression of hypothalamic temperature and a period of peripheral vasodilation in the ear and forepaw foot and toe pads, followed by a drop in rectal temperature. Drinking warm (body temperature) milk did not bring about these changes. Hypothalamic temperature during sleep is lower by approximately 0.5 degrees C and is characterized by widely varying, slow-frequency oscillations, compared to the higher, more precisely controlled temperature seen when the animal is awake.     

Steelhead migration: potential temperature effects as indicated by gill adenosine triphosphatase activities

Yearling steelhead trout held in fresh water at cold temperatures (6.5 degrees or 10 degrees C) showed an increase in gill microsomal Na(+), K(+)-stimulated adenosine triphosphatase activity during parr-smolt transformation, whereas trout held in warm water (15 degrees or 20 degrees C) did not. Adenosine triphosphatase activity increased and other indications of transformation were observed in fish transferred from warm to cold water, whereas the reverse occurred on transfer from cold to warm water.     

Isotopic composition of old ground water from lake agassiz: implications for late pleistocene climate

A uniform oxygen isotope value of -25 per mil was obtained from old ground water at depths of 20 to 30 meters in a thick deposit of clay in the southern part of the glacial Lake Agassiz basin. The lake occupied parts of North Dakota and southern Manitoba at the end of the last glacial maximum and received water from the ice margin and the interior plains region of Canada. Ground water from thick late Pleistocene-age clay deposits elsewhere, a till in southern Saskatchewan, and a glaciolacustrine deposit in northern Ontario show the same value at similar depths. These sites are at about 50 degrees N latitude, span a distance of 2000 kilometers, and like the Lake Agassiz sites, have a ground-water velocity of less than a few millimeters per year. The value of -25 per mil is characteristic of meltwater impounded in the southern basin of Lake Agassiz. This value corresponds to an estimated air temperature of -16 degrees C, compared with the modern temperature of 0 degrees C for this area.     

Thirst satiation and the temperature of ingested water

Ingestion in rats given limited daily access to water of 12 degrees , 24 degrees , and 37 degrees C is a positive function of water temperature, even though ingestion of warm water decreases blood osmotic concentration faster than cold water. The paradox suggests that temperature-dependent gastric factors and water-transport factors determine stomach distention cues of thirst satiation.     

Water and carbon in rusty lunar rock 66095

Lunar rock 66095 contains a hydrated iron oxide and has an unusual amount of water for a lunar rock (140 to 750 parts per million), 90 percent of which is released below 690 degrees C. The deltaof water released at these low temperatures varies from -75 to -140 per mil relative to standard mean ocean water (SMOW). The small amount of water released between 690 degrees and 1300 degrees C has a delta of about -175 +/-25 per mil SMOW. These delta values are not unusual for terrestrial water. The delta(18)O of water extracted from 110 degrees to 400 degrees C has a value of +5+/- I per mil SMOW, similar to the value for lunar silicates from rock 66095 and different from the value of -4 to -22 per mil found for samples of terrestrial rust including samples of rusted meteoritic iron. The amount of carbon varies from 11 to 59 parts per million with a delta(13)C from -20 to -30 per mil relative to Pee Dee belemnite. Only very small amounts of reduced species (such as hydrogen, carbon monoxide, and methane) were found, in contrast to the analyses of other lunar rocks. Although it is possible that most of the water in the iron oxide (goethite) may be terrestrial in origin or may have exchanged with terrestrial water during sample return and handling, evidence presented herein suggests that this did not happen and that some lunar water may have a deltaD that is indistinguishable from that of terrestrial water.     

Deep, zonal subequatorial currents

Large-scale, westward-extending tongues of warm (Pacific) and cold (Atlantic) water are found between 2000 and 3000 meters both north and south of the equator in the Pacific and Atlantic oceans. They are centered at 5 degrees to 8 degrees north and 10 degrees to 15 degrees south (Pacific) and 5 degrees to 8 degrees north and 15 degrees to 20 degrees south (Atlantic). They are separated in both oceans by a contrasting eastward-extending tongue, centered at about 1 degrees to 2 degrees south, in agreement with previous helium isotope observations (Pacific). Thus, the indicated deep tropical westward flows north and south of the equator and eastward flow near the equator may result from more general forcing than the hydrothermal forcing previously hypothesized.     

Ross ice shelf sea temperatures

Two temperature profiles recorded by a sensitive bathythermograph at the Ross Ice Shelf Project site (82 degrees 22.5'S, 168 degrees 37.5'W) are presented. From the shape of the profiles it is concluded that an inflow of water at intermediate depths provides a source of heat to drive a regime in which ice is melted from the interface at a depth of 360 meters. Melting maintains the temperature of a thick layer under the ice at about -2.14 degrees C, close to the ambient freezing temperature. A very well mixed layer about 35 meters thick was found at the seabed.     

Climate impact of late quaternary equatorial pacific sea surface temperature variations

Magnesium/calcium data from planktonic foraminifera in equatorial Pacific sediment cores demonstrate that tropical Pacific sea surface temperatures (SSTs) were 2.8 degrees +/- 0.7 degrees C colder than the present at the last glacial maximum. Glacial-interglacial temperature differences as great as 5 degrees C are observed over the last 450 thousand years. Changes in SST coincide with changes in Antarctic air temperature and precede changes in continental ice volume by about 3 thousand years, suggesting that tropical cooling played a major role in driving ice-age climate. Comparison of SST estimates from eastern and western sites indicates that the equatorial Pacific zonal SST gradient was similar or somewhat larger during glacial episodes. Extraction of a salinity proxy from the magnesium/calcium and oxygen isotope data indicates that transport of water vapor into the western Pacific was enhanced during glacial episodes.     

Liquid water in frozen tissue: study by nuclear magnetic resonance

Nuclear magnetic resonance (NMR) spectroscopy was used to examine the behavior and extent of liquid water in postrigor-frozen tissue of cod at temperatures below 0 degrees C. A liquid-water phase persists in the tissue down to about -70 degrees C; the extent of the phase decreases rapidly between 0 degrees and -10 degrees C and slowly at lower temperatures. That the NMR absorption peak of the liquid water increases in width, with decreasing temperature, suggests loss of mobility or structuring of the phase. A technique for introducing geometrically uniform cores of muscle into the probe of the high-resolution spectrometer permits quantitative determinations of liquid water.     

Thermal reinforcement and thermoregulatory behavior in the goldfish,Carassius auratus

Goldfish in a warm environment can cause a small drop in the temperature of their environment by pressing a lever. The fish regulate the temperature of their environment, keeping the temperature between 33.5 degrees and 36.5 degrees C most of the time.     

Temperature-dependence of resistance at an electrotonic synapse

The junctional resistance at septa of the crayfish lateral giant axon is inversely related to temperature with a Q(1l), of about 3 over the range from 5 degrees to 20 degrees C. Nonjunctional axonal membrane is much less affected. Resistance changes occur rapidly with temperature changes. No correlates in ultrastructure of the synapses have been found.     

Temperature Fluctuations Accompanying Water Movement through Porous Media

Temperature measurements were made at localized sites in bentonite, kaolinite, and small glass beads during infiltration. The temperature of the medium was observed to rise gradually and then to drop sharply as the infiltrating water approached and reached the measurement site. Temperature fluctuations were observed to be about 9 degrees C for bentonite, 4 degrees C for kaolinite, and 0.1 degrees C for the glass beads.     

Thoracic Temperature Stabilization byn Blood Circulation in a Free-Flying Moth

The sphinx moth, Manduca sexta, maintains its thoracic temperature within a degree of 42 degrees C while in free flight over a range of air temperatures from about 17 degrees to 32 degrees C. Tying off the dorsal vessel abolishes temperature control. Moths with tied off vessels overheat and then stop flying at air temperatures of about 23 degrees C. However, flight at this temperature is possible when the thoracic scales are removed. The mechanism of temperature control involves transfer of the heat produced in the thorax to the blood pumped from the dorsal vessel, and the subsequent dissipation of this heat when the blood returns to the relatively cool abdomen.     

Geothermal System at 21{degrees}N, East Pacific Rise: Physical Limits on Geothermal Fluid and Role of Adiabatic Expansion

Pressure-volume-temperature relations for water at the depth of the magma chamber at 21 degrees N on the East Pacific Rise suggest that the maximum subsurface temperature of the geothermal fluid is about 420 degrees C. Both the chemistry of the discharging fluid and thermal balance considerations indicate that the effective water/rock ratios in the geothermal system are between 7 and 16. Such low ratios preclude effective metal transport at temperatures below 350 degrees C, but metal solubilization at 400 degrees C and above is effective even at such low ratios. It is proposed that the 420 degrees C fluid ascends essentially adiabatically and in the process expands, cools, and precipitates metal sulfides within the upper few hundred meters of the sea floor and on the sea floor itself.     

Hemoglobin Kinetics of the Galapagos Rift Vent Tube Worm Riftia pachyptila Jones (Pogonophora; Vestimentifera)

Kinetics of the reactions of Riftia pachyptila hemoglobin with oxygen were followed spectrophotometrically by stopped-flow and laser flash photolysis techniques. The rate of oxygen dissociation increases eightfold over the range of 5 degrees to 20 degrees C (k = 2.2 sec(-1)at 10 degrees C). Oxygen recombination after flash photolysis was biphasic. The rates of both slow and fast phases of the reaction were independent of temperature from 0 degrees to 20 degrees C(k'fast = 7 x 10(6); k'slow = 1 x 16(6) liter mole (-1) sec(-1)). As the oxygen affinity is relatively temperature independent, analysis in terms of the two-state model of cooperativity requires that the conformational equilibrium constant L decrease by about 50-fold between 3 degrees and 15 degrees C.     

Silver-Foil Psychrometer for Measuring Leaf Water Potential in situ

The water potential of leaves in situ can be measured without temperature control with a miniature, single-junction psychrometer constructed from silver foil and attached to the leaf with a silver-impregnated, conductive coating. The temperature of the psychrometer has been found to stay within 0.025 degrees C of the temperature of a simulated leaf when the latter temperature was changing at a rate of 1 degrees C per minute. Leaf water potentials can be measured with a precision of +/- 1 bar, or better.     

Evaporative water loss of small vertebrates,as measured with an infrared analyzer

Evaporation is linearly and inversely related to absolute humidity at 26 degrees to 27 degrees C. The relative rate of loss in desert reptiles, rodents, and anurans is about 1:10:40. The maximum rate of water loss is about 2.5 and 5 times the basal rate, respectively, in pocket mice and sand lizards. The ratio of loss from lung to loss from skin is about 84:16 in kangaroo rats and 70:30 in rattlesnakes.     

Interstitial Silica and pH in Marine Sediments: Some Effects of Sampling Procedures

The temperature at which the interstitial water was squeezed from a marine sediment had a profound effect on the measured interstitial silica concentrations which showed an average increase of 51 percent after the sediment was exposed to a temperature 20 degrees C higher than the in situ temperature. Similar effects were not found for interstitial phosphate or alkalinity, but the pH was slightly higher in the water squeezed at the higher temperature. These tempreature-induced changes were completed in a few hours. The use of filter paper can significantly lower the pH of expressed pore waters. Until some important questions about temperature effects are answered, all future data on the pH and silica concentration of pore waters of marine sediments should be obtained from samples extracted at in situ temperatures.     

Tiliqua scincoides: temperature-sensitive units in lizard brain

Extracellular action potentials were recorded from units in the preoptic area of the brain of the Australian blue-tongued skink (Tiliqua scincoides) during periods of local heating and cooling of the brain (20 degrees to 36 degrees C) with water-perfused thermodes. In this temperature range most spontaneously firing neurons were temperature-insensitive, but eight showed sensitivity to the thermal stimulus. Five warm neurons increased their activity when the brain temperature was raised, and three cold neurons showed increased activity with fall in temperature.     

一个天然水体硅藻区系的演替

本文报导了山西省太谷县一个天然水体硅藻区系的演替。标本自1979年11月到1981年1月逐月定点采集,初步鉴定的结果,共10科25属104个分类单位。从逐月硅藻种类的消长情况,看出该水体硅藻区系的演替,其中一些种常年出现,如:库津小环藻叔曼变种Cyclotella kuetzingiana var。Schumannii Grun,变异直链藻Melosira varians Ag。新月形桥弯藻Cymbella cymbiformis(Ag？Kuetz)V.H.另一些种从4月或6月到次年1月出现,前者如:弯羽纹藻Pinnularia gibba Ehr,后者如:短角美壁藻Caloneis silicula(Ehr.)Cl,有些种在一年中仅出现1——2次,如:大美壁藻Caloneis permagna(Bailey.)Cleve.,彩虹长篦藻Neidium iridis(Ehr.)Cl.,作者认为常年出现的种对温度反应极为迟钝。而一年中仅出现1——2次的种则对温度反应极为敏感。如果在某一个时期一些种大量出现,可以看作这种温度为最适温度,如;弯羽纹藻P.gibba Ehr。10月气温16℃,水温14℃。这样就提供了培养硅藻的温度范围。同时,也可以作为鉴定化石硅藻时推测当时(古气候)的参考。