Performance of group-housed growing pigs at and below lower critical temperature

1990 ◽  
Vol 1990 ◽  
pp. 78-78
Author(s):  
P.H. Simmins ◽  
A.W. Armsby ◽  
S.A. Edwards ◽  
A.T. Smith
Keyword(s):  
Critical Temperature ◽  
Small Groups ◽  
Minimum Temperature ◽  
Room Temperature ◽  
Ventilation Rate ◽  
Growing Pigs ◽  
Temperature Differential ◽  
Airborne Contaminants ◽  
Controlled Conditions ◽  
Lower Critical Temperature

Intensive pig housing often provides an environment with high levels of airborne contaminants which may be to the detriment of the health and welfare of the pig and the stockman. The problem is compounded by producers maintaining higher temperatures than necessary in an attempt to maximise performance. Consequently, air changes in a room may be unduly limited, particularly when the temperature differential between the outside and inside is large as in winter. It is therefore desirable to keep the room temperature as low as possible to maximise ventilation rate whilst ensuring that feed is used efficiently for growth. The temperature above which this occurs is the lower critical temperature (LCT). However current recommendations for LCT are based on research carried out on individuals and very small groups. Commercially, the variability of the group may have a significant effect on the practical minimum temperature which may be achieved. The objective of the trial reported here was to assess the performance of larger groups of pigs grown in controlled conditions utilising current recommendations for LCT based on the Bruce and Clark (1979) model.

Effect of ambient temperature on energy metabolism in growing pigs

1987 ◽  
Vol 44 (3) ◽  
pp. 427-433 ◽  
Author(s):  
J. M. F. Verhagen ◽  
A. A. M. Kloosterman ◽  
A. Slijkhuis ◽  
M. W. A. Verstegen
Keyword(s):  
Critical Temperature ◽  
Energy Metabolism ◽  
Food Intake ◽  
Ambient Temperature ◽  
Growing Pigs ◽  
Initial Exposure ◽  
Maintenance Requirement ◽  
Lower Critical Temperature ◽  
Two Temperatures ◽  
Ad Libitum

ABSTRACTGroup-housed young growing pigs, given food ad libitum, were exposed to two temperatures, one within thermal neutrality (25°C) and one around the lower critical temperature (15°C). Pigs at 15°C had daily gains reduced by 57 g for 6 days after initial exposure. Food intake was increased significantly after 6 days at 15°C but not at 25°C. Maintenance requirement was increased by 58 kJ/kg M0·75 and energy retained as protein was decreased by 49 kJ/kg M0·75 for the first 6 days after exposure to the treatment of 15°C and thereafter both became equivalent to those of pigs at 25°C afterwards. It is concluded that animals were acclimatized after 6 days exposure.

scholarly journals DATA ON THE DEVELOPMENT OF HETERAKIS PAPILLOSA IN THE FOWL

1921 ◽  
Vol 34 (3) ◽  
pp. 259-270 ◽  
Author(s):  
H. W. Graybill
Keyword(s):  
Small Intestine ◽  
Salt Solution ◽  
Final Stage ◽  
Minimum Temperature ◽  
Growth And Development ◽  
Room Temperature ◽  
Freezing Temperature ◽  
Physiological Salt Solution ◽  
Natural Conditions ◽  
Short Intervals

In observations on the development of the ova of Heterakis papillosa in cultures, it was found that they failed to develop at a temperature ranging from 2.5–8°C., but developed slowly at a temperature of 11.5–13.5°C. The minimum temperature for development seems to lie between 8° and 11.5–13.5°C. At temperatures ranging in various cultures from 18–29°C. ova developed to their final stage in 7 to 12 days. Undeveloped ova subjected to a freezing temperature for a period of 4 days were viable at the end of that time. Fully developed ones remained alive when exposed out of doors for a period of 7 days at a temperature ranging from 5–62°F. Undeveloped ova survived desiccation at room temperature for a period of 16 days, but not for 41 days. Fully developed eggs were alive after desiccation for 18 days, but not after 49 days. In another instance they were no longer viable after 10 days. Embryos within ova kept in physiological salt solution at room temperature survived during a period of a little over 12 months. Fully developed ova kept in soil outdoors under circumstances approaching natural conditions contained living embryos after a period of 8 months. From a study of a series of artificially infested chickens killed at short intervals it appears that the ova of Heterakis hatch in the small intestine and the larvæ pass by way of the small and large intestines to the ceca where they undergo development to maturity. Larvæ found in the mucosa of the ceca were not in an encysted condition. Feeding of numerous artificially incubated ova may lead to a light infestation, the cause of which has not been definitely determined. A period of 57 days was required for larvæ to reach maturity in a host. The entire cycle from egg to adult requires a minimum time of about 64 days. A brief study of the growth and development of larvæ within the host has been made. No evidence was found of a migration through the tissues. A few penetrate into the mucosa of the ceca.

Crystalline-To-Amorphous Transformation of Intermetallic Compounds in the Zr-Fe-M System Induced by Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
Arthur T. Motta ◽  
Lawrence M. Howe ◽  
Paul R. Okamoto
Keyword(s):  
Critical Temperature ◽  
Low Temperature ◽  
Dose Rate ◽  
Intermetallic Compounds ◽  
Electron Energy ◽  
Energy Dependence ◽  
Electron Irradiation ◽  
Critical Temperatures ◽  
Lower Critical Temperature ◽  
Ternary Intermetallic Compounds

AbstractThe binary and ternary intermetallic compounds Zr3Fe, Zr2 Fe, (Zr0.5,Nb0.5)3Fe, Zr3(Fe0.9,Ni0.1) and Zr3(Fe0.5,Ni0.5) were subjected to 900 keV electron irradiation until amorphous to study the change in the dose-to-amorphization with temperature. The critical temperatures were observed to vary with dose rate, and with the type of compound. Hexagonal (Zr0.5,Nb0.5)3Fe had an appreciably lower critical temperature and higher dose to amorphization at low temperature than orthorombic Zr3Fe, whereas other orthorombic Zr3(Fex,NiI-x) compounds were essentially identical in behavior to Zr3Fe. The electron energy dependence of the dose-to-amorphization was studied in Zr3Fe between 250 and 900 keV. The analysis of the results gives displacement energies of EZrd = 26 eV, EFed = 18 eV in the Zr3Fe compound.

scholarly journals Laboratory Metabolism of Incubating Semipalmated Plovers

The Condor ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 966-970
Author(s):  
Mark Williamson ◽  
Joseph B. Williams ◽  
Erica Nol
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Breeding Season ◽  
Basal Metabolic Rate ◽  
Low Temperatures ◽  
Thermal Conductance ◽  
Basal Metabolism ◽  
The Arctic ◽  
Lower Critical Temperature ◽  
Metabolic Data

Abstract Abstract The Semipalmated Plover (Charadriussemipalmatus), anarctic-nesting migratory shorebird, regularlyencounters low temperatures during the breedingseason. We measured the basal metabolism of adultsduring incubation at Churchill, Manitoba, Canada todetermine basal metabolic rate (BMR),lower critical temperature(Tlc), total evaporative waterloss (TEWL), and dry thermal conductance(Cm). BMR and Tlcwere 47.4 kJ day−1and 23.3°C, respectively, TEWL was2.5 mL H2O−d,and Cm was1.13 mW g−1 °C−1.Measured BMR and Tlc were consistentwith high values found for other shorebird speciesbreeding in the Arctic, while Cm was18% higher than predicted from allometricequations. These metabolic data suggest thatSemipalmated Plovers are adapted to balance therequirements of incubation against energetic andthermoregulatory demands in the Arctic, especiallyin harsh early breeding season conditions.

Regulation of metabolic rate in Svalbard and Norwegian reindeer

1984 ◽  
Vol 247 (5) ◽  
pp. R837-R841 ◽  
Author(s):  
K. J. Nilssen ◽  
J. A. Sundsfjord ◽  
A. S. Blix
Keyword(s):  
Body Weight ◽  
Critical Temperature ◽  
Food Intake ◽  
Metabolic Rate ◽  
Seasonal Changes ◽  
Serum Levels ◽  
Physiological Adaptation ◽  
Conservation Of Energy ◽  
Winter Food ◽  
Lower Critical Temperature

Food intake, body weight, serum levels of triiodothyronine (T3) and free thyroxine (FT4), and metabolic rate were measured at intervals in Svalbard (SR) and Norwegian (NR) reindeer. From summer to winter food intake decreased 57 (SR) and 55% (NR), while body weight decreased 8.6 (SR) and 3.8% (NR). In SR T3 and FT4 changed seasonally, whereas this was only evident for T3 in NR. Resting (standing) metabolic rate (RMR) in winter was 1.55 (SR) and 2.05 W X kg-1 (NR), lower critical temperature (TLC) being -50 (SR) and -30 degrees C (NR). RMR in summer was 2.15 (SR) and 2.95 W X kg-1 (NR), TLC being -15 (SR) and 0 degrees C (NR). Seasonal changes in T3 and FT4 did not coincide with changes in food intake or RMR in either SR or NR. RMR did, however, correlate with food intake. This indicates that seasonal changes in RMR are due to the thermic effects of feeding and represent no physiological adaptation aimed at conservation of energy during winter.

How Reliable is the Cuprates System to Recent Technology?

2016 ◽  
Vol 6 (4) ◽  
pp. 1534
Author(s):  
Emetere M.E. ◽  
Awojoyogbe O.B. ◽  
Uno U.E. ◽  
Isah K.U. ◽  
Sanni E.S. ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Room Temperature ◽  
Engineering Application ◽  
Experimental Results ◽  
Future Research ◽  
Mathematical Approach ◽  
Experimental Room ◽  
High Tc ◽  
High Tc Superconductor

The emergence of cuprates as a high Tc superconductor gave high hopes in the discovery of a room temperature superconductor. It is almost three decades and the highest critical temperature attained on the cuprates is about 135K. A brief overview was conducted on the progress made so far on the cuprates. A mathematical approach was used to design a formula which could determine the experimental results of critical temperature of versed cuprates superconductors. The result of our findings shows that the possibility of attaining the experimental room temperature cuprates superconductor seems very narrow. The study recommended an elaborate approach on the hybridization of cuprates for future research. Hence, there is possibility of having cuprates with wide engineering application.

scholarly journals Moiré with flat bands is different

2019 ◽  
Vol 50 (3) ◽  
pp. 24-26
Author(s):  
Tero T. Heikkilä ◽  
Timo Hyart
Keyword(s):  
Critical Temperature ◽  
Fermi Surface ◽  
Room Temperature ◽  
Electronic States ◽  
Bilayer Graphene ◽  
Flat Bands ◽  
Twisted Bilayer Graphene

Recent experimental discoveries of superconductivity and other exotic electronic states in twisted bilayer graphene (TBG) call for a reconsideration of our traditional theories of these states, usually based on the assumption of the presence of a Fermi surface. Here we show how such developments may even help us finding mechanisms of increasing the critical temperature of superconductivity towards the room temperature.

THE POLARIZATION OF LIQUIDS AND THEIR SATURATED VAPORS IN THE CRITICAL TEMPERATURE REGION

1936 ◽  
Vol 14b (3) ◽  
pp. 90-95
Author(s):  
J. Marsden ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Methyl Ether ◽  
Temperature Region ◽  
Room Temperature ◽  
Saturated Vapor ◽  
Dielectric Constants

The values of the so-called polarization of methyl ether (liquid and saturated vapor) and propylene (liquid and saturated vapor), from room temperature to the critical temperature, are given. In both liquids this polarization is independent of the temperature to within a few degrees of the critical temperature. Calculations show that the polarizations of a liquid and its saturated vapor may be equal above the critical temperature, even though the dielectric constants of the liquid and its saturated vapor, as well as their densities, are different.

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