3,058 research outputs found
Popular Cultural Keystone Species are also understudied — the case of the camphor tree (Dryobalanops aromatica)
Along with landscape degradation and loss of biodiversity there is also a co-occurring loss of cultural and linguistic diversity. When species become rare, there is a corresponding loss of cultural practices and linguistic elements associated with that species. Although cultural assessments of tree species can help in identifying Cultural Keystone Species (CKS) and be used to enhance the cultural relevance of conservation actions, such information is typically lacking for endangered species were the cultural connections may have been lost. Here, we review historic written accounts to assess the cultural status of the critically endangered camphor tree, Dryobalanops aromatica, native to Southeast Asia which is recognized for its camphor and crystals forming in the wood. We found that despite centuries of use, the importance of the tree for specific cultures has not been fully understood. Published literature indicate that it could be a CKS to multiple communities. The tree was once culturally significant for many cultures in its native range and beyond, but contemporary data is lacking, especially with respect to persistence and memory of use in relation to cultural change. By virtue of being a culturally recognized tree species, as well as having a distinct ecological role within its natural distribution, we propose D. aromatica as a flagship species for conservation and restoration of the habitat it defines. Our review highlights the usability of historic accounts as starting points for identifying CKS and effective conservation of biocultural diversity, especially concerning endangered species. We propose that future research should pay attention to inter and intra-community dynamics of local knowledge on the species, and causes and consequences of varying cultural importance across temporal and spatial scale
Phonon Squeezed States Generated by Second Order Raman Scattering
We study squeezed states of phonons, which allow a reduction in the quantum
fluctuations of the atomic displacements to below the zero-point quantum noise
level of coherent phonon states. We investigate the generation of squeezed
phonon states using a second order Raman scattering process. We calculate the
expectation values and fluctuations of both the atomic displacement and the
lattice amplitude operators, as well as the effects of the phonon squeezed
states on macroscopically measurable quantities, such as changes in the
dielectric constant. These results are compared with recent experiments.Comment: 4 pages, REVTE
Magnetic Raman Scattering in Two-Dimensional Spin-1/2 Heisenberg Antiferromagnets: Spectral Shape Anomaly and Magnetostrictive Effects
We calculate the Raman spectrum of the two-dimensional (2D) spin-1/2
Heisenberg antiferromagnet by exact diagonalization and quantum Monte Carlo
techniques on clusters of up to 144 sites and, on a 16-site cluster, by
considering the phonon-magnon interaction which leads to random fluctuations of
the exchange integral. Results are in good agreement with experiments on
various high-T_c precursors, such as La_2CuO_4 and YBa_2Cu_3O_{6.2}. In
particular, our calculations reproduce the broad lineshape of the two-magnon
peak, the asymmetry about its maximum, the existence of spectral weight at high
energies, and the observation of nominally forbidden A_{1g} scattering.Comment: 12 pages, REVTEX, 1 postscript figur
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