Chalk River Laboratories

About: Chalk River Laboratories is a based out in . It is known for research contribution in the topics: Neutron diffraction & Neutron scattering. The organization has 2297 authors who have published 2700 publications receiving 73287 citations.

Cooperative Paramagnetism in the Geometrically Frustrated Pyrochlore Antiferromagnet Tb 2 Ti 2 O 7

Abstract: Neutron scattering, muon spin relaxation, and dc susceptibility studies have been carried out on polycrystalline ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$, a pyrochlore antiferromagnet in which the ${\mathrm{Tb}}^{3+}$ moments reside on a network of corner-sharing tetrahedra. Unlike other geometrically frustrated systems, ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ remains paramagnetic down to $\ensuremath{\sim}0.07\mathrm{K}$, rather than ordering into a conventional N\'eel or spin-glass-like state, despite the fact that short-range antiferromagnetic correlations (AFC) develop at $\ensuremath{\sim}50\mathrm{K}$. At the first AFC wave vector, its low-lying, relatively flat magnetic excitation spectrum softens partially below 30 K.

A Study of the Relation of Meteorological Variables to Monthly Provincial Area Burned by Wildfire in Canada (1953–80)

Abstract: The relation between meteorological variables and the monthly area burned by wildfire from May to August 1953–80 in nine Canadian “provinces” was investigated. A purely statistical approach to estimating the monthly provincial area burned, using meteorological variables as predictors, succeeded in explaining 30% of the variance west of Lake Nipigon and about 11% east of Lake Nipigon. Long sequences of days with less than 1.5 mm of rain or days with relative humidities less than 60% proved to have the highest correlation with area burned. These long sequences were assumed to be associated with blocking highs in the westerlies. Bad fire months were independent of rainfall amount but significantly dependent on rainfall frequency, temperature, and relative humidity.

Segregation of random amplified DNA markers in F1 progeny of conifers

Abstract: The recently developed approach to deriving genetic markers via amplification of random DNA segments with single primers of arbitrary nucleotide sequence was tested for its utility in genetic linkage mapping studies with conifers. Reaction conditions were optimized to reproducibly yield clean and specific amplification products. Template DNA from several genotypes of Douglas-fir (Pseudotsuga menziesii) and white spruce (Picea glauca) were tested against eight ten-base oligonucleotide primers. Most of the tested primer/parent tree combinations yielded polymorphic PCR products ("RAPD" markers). Selected primers were then used in PCR reactions with template DNA isolated from offspring in Douglas-fir and black spruce diallel crosses among the same parental lines. The diallel study confirmed the appropriate inheritance of RAPD markers in the F1 generation. The value of these dominant RAPD markers for genetic linkage mapping in trees was established from both theoretical and applied perspectives.