Nuclear magnetic resonance on oriented rare-earth nuclei in rare-earth hosts: Application to 160Tb.
We summarize the application of nuclear magnetic resonance of oriented nuclei to rare-earth impurities implanted in ferromagnetic crystals of heavy rare-earth hosts. The experimental aspects are treated in some detail; we present results obtained on $^{160}\mathrm{Tb}$$\mathrm{Tb}$, and give a formal description of the experiments. A discussion of extension to other, similar systems with applications in nuclear, solid-state, and low-temperature physics is given.
Magnetic behaviour of Tb impurities in Gd andY single crystals: a nuclear orientation study
The low temperature nuclear orientation of160Tb impurities in Gd andY single crystals has been studied in the temperature range 7–40 mK andin the external magnetic field range 0–7.3 T applied alonga-, b- andc-crystal axes. In the case of Tb in Gd we found a considerable noncollinearity of the Tb magnetic moment with respect to the magnetic external field direction even for highBext. In the case of Tb in Y the results cannot be described by a simple model, taking into account the simultaneous influence of the crystal andexternal magnetic fields. Some new proposals for interpretation of the experimental dat are given.
Vertebral Fusion in Two Early Jurassic Sauropodomorph Dinosaurs from the Lufeng Formation of Yunnan, China
Here we describe two instances of pathological vertebral fusion in two genera of sauropodomorph dinosaurs from the Early Jurassic Lufeng Formation in Yunnan, China. The first is a specimen, of Lufengosaurus huenei with two fused cervical vertebrae, and the other is a specimen of the Lufeng basal sauropod, with two fused caudal vertebrae. Both pathologies are consistent with spondyloarthropathy and represent the earliest known occurrence of that disease in dinosaurs. The two specimens affirm that early dinosaurs suffered from the same bone diseases as living vertebrates. Spondyloarthropathy in these dinosaurs may have been induced by long-term mechanical stress, such as weight bearing, and/or limited motion at the joint that would otherwise have inhibited such remodeling. In both cases, surface remodeling suggests that the animals survived well beyond the initiation of spondyloarthropathy.