scholarly journals Thermally induced torpor in fullterm lizard embryos synchronizes hatching with ambient conditions

2006 ◽  
Vol 2 (3) ◽  
pp. 415-416 ◽  
Author(s):  
Rajkumar Radder ◽  
Richard Shine
Keyword(s):  
Environmental Conditions ◽  
Low Temperatures ◽  
Access To Information ◽  
Ambient Conditions ◽  
Thermally Induced ◽  
Ambient Temperatures ◽  
Ground Conditions ◽  
Soil Temperatures ◽  
Bassiana Duperreyi ◽  
Do So

Eggs inside an underground nest have limited access to information about above-ground conditions that might affect the survival of emerging hatchlings. Our measurements of heart rates of embryos inside the intact eggs of montane lizards ( Bassiana duperreyi , Scincidae) show that low temperatures induce torpor in fullterm embryos, but do not do so during earlier embryogenesis or later, post-hatching. Because above-ground conditions affect soil temperatures, this stage-dependent torpor effectively restricts hatching to periods of high ambient temperatures above ground. Torpor thus can function not only to synchronize activity with suitable environmental conditions during post-hatching life (as reported for many species), but also can occur in embryos, to synchronize hatching with above-ground conditions that facilitate successful emergence from the nest.

scholarly journals Modeling of Monocrystalline PV Cell Considering Ambient Conditions in Baghdad City

2017 ◽  
Vol 13 (3) ◽  
pp. 74-82
Author(s):  
Mohammed E. Abd Al-Wahed ◽  
Osamah F. Abdullateef
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Ambient Temperature ◽  
Output Power ◽  
Environmental Conditions ◽  
Photovoltaic Module ◽  
Power Performance ◽  
Ambient Conditions ◽  
Cell Temperature ◽  
Ambient Temperatures

Abstract   The environmental conditions are important factors, because they affect both the efficiency of a photovoltaic module and the energy load. This research was carried out experimentally and modeling was done in MATLAB –Simulink by monitoring the variation in power output of the system with environmental conditions such as solar radiation, ambient temperature, wind speed, and humidity of Baghdad city. From the results, the ambient temperatures are inversely proportional to humidity and the output power performance of the system, while the wind speed is directly proportional with the output power performance of the system.     Keywords: Ambient temperature, cell temperature, humidity, Photovoltaic, solar radiation, wind speed.

Strategies and adaptations to aquatic life at high altitude

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Environmental Conditions ◽  
Low Temperatures ◽  
Cold Adaptation ◽  
Inorganic Carbon ◽  
Direct Result ◽  
Aquatic Life ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Regulatory Capacity

Chapter 5 is focused on how organisms cope with the environmental conditions that are a direct result of high altitude. Organisms reveal a number of fascinating ways of dealing with a life at high altitude; for example, avoidance and pigmentation as protection against damaging high levels of ultraviolet radiation, accumulation of antifreeze proteins, and metabolic cold adaptation among species encountering low temperatures with the risk of freezing, oxy-regulatory capacity in animals due to low availability of oxygen, and root uptake from the sediment of inorganic carbon by plants living in waters poor in dissolved carbon dioxide. These and more adaptations are carefully described through a number of examples from famous flagship species in addition to the less well-known ones. Harsh environmental conditions work as an environmental filter that only allows the well-adapted species to slip through to colonize high altitude waters.

Testing Long-Term Predictions from Hydro-Geochemical Models

1993 ◽  
Vol 333 ◽  
Author(s):  
William E. Glassley ◽  
Carol J. Bruton ◽  
William L. Bourcier
Keyword(s):  
Yucca Mountain ◽  
Taupo Volcanic Zone ◽  
Ambient Conditions ◽  
Volcanic Zone ◽  
Site Specific ◽  
Thermally Induced ◽  
Induced Flow ◽  
Geochemical Models ◽  
Kinetics And Thermodynamic

ABSTRACTThermally induced flow of liquid water and water vapor at the potential repository site at Yucca Mountain, Nevada, will extend hundreds of meters away from the repository edge. The resultant transfer of heat and mass will sufficiently perturb the ambient conditions such that a variety of mineralogical and chemical reactions will occur that may modify hydrological properties. The consequences of this “coupling” of geochemical and hydrological processes will vary through time, and will occur to different degrees in four regimes (T < Tboiling; T = Tboiling; T > T boiling; cooling) that will develop within the repository block. The dominant processes in the regimes differ, and reflect the local balance between: 1) kinetics and equilibrium; 2) dissolution and precipitation; 3) evaporation and boiling; and 4) fluid flow in matrix and fractures. Simulations were conducted of the evolution of these regimes, using laboratory derived kinetics and thermodynamic data, and site specific mineralogical and hydrological properties. These simulations identify regions where chemical and mineralogical equilibrium is likely to be achieved, and where net changes in hydrological properties will be concentrated. Tests of the results of these simulations have been initiated using field data from the Taupo Volcanic Zone, New Zealand. A preliminary series of calculations suggest that relative changes in porosity of as much as ± 20% to 30% may be possible for rocks with an initial porosity of 10%.

Ambient temperatures, heatwaves and out-of-hospital cardiac arrest in Brisbane, Australia

2021 ◽  
pp. oemed-2020-107018
Author(s):  
Tan N Doan ◽  
Daniel Wilson ◽  
Stephen Rashford ◽  
Emma Bosley
Keyword(s):  
Cardiac Arrest ◽  
Temperature Distribution ◽  
Low Temperatures ◽  
Meteorological Data ◽  
Reference Temperature ◽  
Ambient Temperatures ◽  
Distributed Lag ◽  
Exposure Response ◽  
Heat Threshold ◽  
Hospital Cardiac Arrest

BackgroundThe health impacts of temperatures are gaining attention in Australia and worldwide. While a number of studies have investigated the association of temperatures with the risk of cardiovascular diseases, few examined out-of-hospital cardiac arrest (OHCA) and none have done so in Australia. This study examined the exposure–response relationship between temperatures, including heatwaves and OHCA in Brisbane, Australia.MethodsA quasi-Poisson regression model coupled with a distributed lag non-linear model was employed, using OHCA and meteorological data between 1 January 2007 and 31 December 2019. Reference temperature was chosen to be the temperature of minimum risk (21.4°C). Heatwaves were defined as daily average temperatures at or above a heat threshold (90th, 95th, 98th, 99th percentile of the yearly temperature distribution) for at least two consecutive days.ResultsThe effect of any temperature above the reference temperature was not statistically significant; whereas low temperatures (below reference temperature) increased OHCA risk. The effect of low temperatures was delayed for 1 day, sustained up to 3 days, peaking at 2 days following exposures. Heatwaves significantly increased OHCA risk across the operational definitions. When a threshold of 95th percentile of yearly temperature distribution was used to define heatwaves, OHCA risk increased 1.25 (95% CI 1.04 to 1.50) times. When the heat threshold for defining heatwaves increased to 99th percentile, the relative risk increased to 1.48 (1.11 to 1.96).ConclusionsLow temperatures and defined heatwaves increase OHCA risk. The findings of this study have important public health implications for mitigating strategies aimed at minimising temperature-related OHCA.

EFFECTS OF LOW FLUCTUATING TEMPERATURES ON FARM ANIMALS.: III. INFLUENCE OF AMBIENT AIR TEMPERATURE ON FEED INTAKE OF LACTATING HOLSTEIN-FRIESIAN COWS

1958 ◽  
Vol 38 (2) ◽  
pp. 148-159 ◽  
Author(s):  
M. A. MacDonald ◽  
J. M. Bell
Keyword(s):  
Milk Production ◽  
Air Temperature ◽  
Low Temperatures ◽  
Ambient Air ◽  
Feed Consumption ◽  
Ambient Temperatures ◽  
Ambient Air Temperature ◽  
Holstein Friesian ◽  
Cent Level ◽  
Friesian Cows

This report presents effects of low temperatures on the feed consumption and efficiency of milk production of six mature, lactating, Holstein-Friesian cows that were confined in stanchions for three fortnightly experimental periods during which ambient temperatures measured in degree-hours per day (d-h/day) ranged from 110 to 1152 and daily minimum ambient air temperature (DMAAT) varied from 0° to 38°F. Applying results obtained, it was calculated that as temperatures decreased, i.e., d-h/day increased from 100 to 1200 and DMAAT decreased from 40° to 0°F, average daily intakes of total dry matter, hay, and gross and digestible Calories increased approximately 6.4 lb., 5.3 lb., 13 Therms and 9 Therms, respectively. Each of these increases was statistically significant at the 1 per cent level. Reductions in temperature also decreased gross and net caloric efficiencies of milk production approximately 10 and 8.5 per cent, respectively. These decreases were significant at the 2 per cent level. No correlation was evident between crude protein utilization and temperature.Results indicated that thermal stress was not overcome adequately by supplementary hay intake alone and that appetite stimulation by low temperatures had a carry-over effect continuing at least 24 hours. For continued efficient milk production during winters where low ambient temperatures are prevalent these results suggest it is necessary to provide some form of building insulation, ambient heat and/or provide a high energy supplement to otherwise adequate production rations.

Using Thermoelectric Cooling With Tourniquets for Nerve Preservation

2016 ◽  
Author(s):  
M. Trupiano ◽  
S. Aarabi ◽  
A. F. Emery
Keyword(s):  
Thermal Conditions ◽  
Ambient Conditions ◽  
Transfer Coefficients ◽  
Thermoelectric Coolers ◽  
Ambient Temperatures ◽  
Nerve Preservation ◽  
Heat Transfer Coefficients ◽  
Surface Temperatures ◽  
Element Simulation ◽  
Free And Forced Convection

The use of a tourniquet leads to nerve damage, even if applied for short periods of time. This damage can be minimized if the limb is cooled. Because of the low conductivities of human tissue, core limb cooling is slow unless the surface temperature is very cool. Subzero surface temperatures can lead to skin injury (i.e., frostbite). Ideally one would adjust the limb surface temperatures as a function of time to maximize the cooling rate while avoiding permanent tissue damage. One possible approach is to use a thermoelectric cooler (TEC) in conjunction with a programmable power supply. TEC performance varies strongly with heat absorption rate, a function of limb thermal properties, and hot side temperatures that are strongly affected by the surface conditions on the hot side, i.e., overall heat transfer coefficients and ambient conditions. The paper describes the use of finite element simulation to predict the usefulness of using thermoelectric coolers applied to the surface of a limb when compared to the standard approach of using ice packs. Since the TEC performance is strongly influenced by its warm side thermal conditions, experimental results are presented for different ambient temperatures, free and forced convection, and evaporation of water from a wickable covering.

scholarly journals Increased microbial expression of organic nitrogen cycling genes in long-term warmed grassland soils

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Joana Séneca ◽  
Andrea Söllinger ◽  
Craig W. Herbold ◽  
Petra Pjevac ◽  
Judith Prommer ◽  
...  
Keyword(s):  
Nitrogen Cycling ◽  
Cell Walls ◽  
Organic Nitrogen ◽  
Soil Microbial Communities ◽  
Microbial Cell ◽  
Ambient Conditions ◽  
Soil Microbial ◽  
Soil Temperatures ◽  
Microbial Turnover

AbstractGlobal warming increases soil temperatures and promotes faster growth and turnover of soil microbial communities. As microbial cell walls contain a high proportion of organic nitrogen, a higher turnover rate of microbes should also be reflected in an accelerated organic nitrogen cycling in soil. We used a metatranscriptomics and metagenomics approach to demonstrate that the relative transcription level of genes encoding enzymes involved in the extracellular depolymerization of high-molecular-weight organic nitrogen was higher in medium-term (8 years) and long-term (>50 years) warmed soils than in ambient soils. This was mainly driven by increased levels of transcripts coding for enzymes involved in the degradation of microbial cell walls and proteins. Additionally, higher transcription levels for chitin, nucleic acid, and peptidoglycan degrading enzymes were found in long-term warmed soils. We conclude that an acceleration in microbial turnover under warming is coupled to higher investments in N acquisition enzymes, particularly those involved in the breakdown and recycling of microbial residues, in comparison with ambient conditions.

scholarly journals Ecological specialization, variability in activity patterns and response to environmental change

2018 ◽  
Vol 14 (6) ◽  
pp. 20180115 ◽  
Author(s):  
Talisin T. Hammond ◽  
Rupert Palme ◽  
Eileen A. Lacey
Keyword(s):  
Environmental Change ◽  
Environmental Conditions ◽  
Phenotypic Variability ◽  
Activity Patterns ◽  
Temporal Patterns ◽  
Past Century ◽  
Ambient Conditions ◽  
Ecological Specialization ◽  
Sympatric Populations ◽  
Individual Level

Differences in temporal patterns of activity can modulate the ambient conditions to which organisms are exposed, providing an important mechanism for responding to environmental change. Such differences may be particularly relevant to ecological generalists, which are expected to encounter a wider range of environmental conditions. Here, we compare temporal patterns of activity for partially sympatric populations of a generalist (the lodgepole chipmunk, Tamias speciosus ) and a more specialized congener (the alpine chipmunk, Tamias alpinus ) that have displayed divergent responses to the past century of environmental change. Although mean activity budgets were similar between species, analyses of individual-level variation in locomotion revealed that T. alpinus exhibited a narrower range of activity patterns than T . speciosus . Further analyses revealed that T. alpinus was more active earlier in the day, when temperatures were cooler, and that activity patterns for both species changed with increased interspecific co-occurrence. These results are consistent with the greater responsiveness of T. alpinus to changes in environmental conditions. In addition to highlighting the utility of accelerometers for collecting behavioural data, our findings add to a growing body of evidence, suggesting that the greater phenotypic variability displayed by ecological generalists may be critical to in situ responses to environmental change.

CALCULATED DETERMINATION OF PRE-HEATING PARAMETERS FOR WELDING POLYETHYLENE PIPES FOR GAS PIPELINES AT LOW AIR TEMPERATURES.

2021 ◽  
pp. 29-31
Author(s):  
I. Tarabukin
Keyword(s):  
Low Temperatures ◽  
Weld Seam ◽  
Gas Pipelines ◽  
Ambient Temperatures ◽  
Regulatory Documents ◽  
Polyethylene Pipes ◽  
Heated Air ◽  
Air Temperatures ◽  
Different Characteristics

According to regulatory documents, welding can be performed at ambient temperatures from minus 15 ° C to plus 45 ° C. When laying gas pipelines at a lower outside temperature, it is necessary to organize their heating to the required temperature. In this case, the temperature of the heated air should not be more than plus 60 ° C. If you start working with a polyethylene (PE) pipe at low temperatures, then the PE pipe will have completely different characteristics. The weld seam may not be reliable.

Development, Longevity and Fecundity of the False Wireworms Pterohelaeus-Darlingensis and Pterohelaeus-Alternatus (Coleoptera, Tenebrionidae) .4. Models for Larval and Pupal Development Under Fluctuating Temperatures

1986 ◽  
Vol 34 (6) ◽  
pp. 815 ◽  
Author(s):  
PG Allsopp
Keyword(s):  
Stochastic Model ◽  
Low Temperatures ◽  
Considerable Variability ◽  
Ambient Conditions ◽  
Pupal Development ◽  
Long Period ◽  
New Models ◽  
The Difference ◽  
Fluctuating Temperatures ◽  
Coleoptera Tenebrionidae

The usefulness of models derived from constant-temperature rearing in predicting development of larvae and pupae of Pterohelaeus darlingensis Carter and P, alternatus Pascoe under fluctuating temperature was determined. In general, these models underestimated development. The magnitude of the difference was proportional to the length of the development period and, by inference, negatively related to the temperatures experienced. New models were developed with data from individuals reared under fluctuating temperatures. The linear model gave better predictions of development under ambient conditions than did the curvilinear Stinner model for pupae of P. darlingensis, but both models gave similar predictions for larvae of both species. Development of P. alternatus pupae was still underestimated by both models. Substantial discrepancies between observed and expected development of individuals reared under a regimen incorporating a long period at low temperatures indicate that such a regimen is deleterious. Given the considerable variability in development rates between individuals, a stochastic model may predict development more accurately.

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