title: Application of impulse radar to continuous profiling of tephra-bearing lake sediments and peats: an initial evaluation

authors: Lowe, David J.

subjects: subsurface interface radar

abstract: Subsurface interface radar SIR, or impulse radar, uses electromagnetic pulses for continuous stratigraphic profiling. It has been applied to lake sediments (dy-gyttja) and peat deposits containing a sequence of thin, late Quaternary, ash-grade tephras at Lake Maratoto, North Island, New Zealand. The SIR system is very rapid, precise, and reasonably accurate compared with conventional coring and probing methods, but still requires good stratigraphic control for reliable interpretation. Radar penetration depths of up to 10 m were attained. Interfaces between lake bottom and lake sediments and underlying volcanogenic materials of varying lithologies could be readily discerned, as could many of the tephra layers preserved within the lake sediments. Peat depths and positions of stumps or logs on the surface of the subpeat materials could also be determined. Given adequate calibration by drilling, the SIR system appears useful for various shallow subsurface exploration studies, particularly those involving tephrostratig raphy and paleoenvironmental reconstructions from limnic and peat deposits, and in projects on buried wood.

text: Application of impulse radar to continuous profiling of tephra-bearing lake sediments and peats: an initial evaluation Subsurface interface radar SIR, or impulse radar, uses electromagnetic pulses for continuous stratigraphic profiling. It has been applied to lake sediments (dy-gyttja) and peat deposits containing a sequence of thin, late Quaternary, ash-grade tephras at Lake Maratoto, North Island, New Zealand. The SIR system is very rapid, precise, and reasonably accurate compared with conventional coring and probing methods, but still requires good stratigraphic control for reliable interpretation. Radar penetration depths of up to 10 m were attained. Interfaces between lake bottom and lake sediments and underlying volcanogenic materials of varying lithologies could be readily discerned, as could many of the tephra layers preserved within the lake sediments. Peat depths and positions of stumps or logs on the surface of the subpeat materials could also be determined. Given adequate calibration by drilling, the SIR system appears useful for various shallow subsurface exploration studies, particularly those involving tephrostratig raphy and paleoenvironmental reconstructions from limnic and peat deposits, and in projects on buried wood.

year: 1985

title: Models of q-algebra representations: q-integral transforms and "addition theorems''

authors: Kalnins, Ernie G.

subjects: Mathematics

abstract: In his classic book on group representations and special functions Vilenkin studied the matrix elements of irreducible representations of the Euclidean and oscillator Lie algebras with respect to countable bases of eigenfunctions of the Cartan subalgebras, and he computed the summation identities for Bessel functions and Laguerre polynomials associated with the addition theorems for these matrix elements. He also studied matrix elements of the pseudo-Euclidean and pseudo-oscillator algebras with respect to the continuum bases of generalized eigenfunctions of the Cartan subalgebras of these Lie algebras and this resulted in realizations of the addition theorems for the matrix elements as integral transform identities for Bessel functions and for confluent hypergeometric functions. Here we work out q analogs of these results in which the usual exponential function mapping from the Lie algebra to the Lie group is replaced by the q-exponential mappings Eq and eq. This study of representations of the Euclidean quantum algebra and the q-oscillator algebra (not a quantum algebra) leads to summation, integral transform, and q-integral transform identities for q analogs of the Bessel and confluent hypergeometric functions, extending the results of Vilenkin for the q=1 case.

text: Models of q-algebra representations: q-integral transforms and "addition theorems'' In his classic book on group representations and special functions Vilenkin studied the matrix elements of irreducible representations of the Euclidean and oscillator Lie algebras with respect to countable bases of eigenfunctions of the Cartan subalgebras, and he computed the summation identities for Bessel functions and Laguerre polynomials associated with the addition theorems for these matrix elements. He also studied matrix elements of the pseudo-Euclidean and pseudo-oscillator algebras with respect to the continuum bases of generalized eigenfunctions of the Cartan subalgebras of these Lie algebras and this resulted in realizations of the addition theorems for the matrix elements as integral transform identities for Bessel functions and for confluent hypergeometric functions. Here we work out q analogs of these results in which the usual exponential function mapping from the Lie algebra to the Lie group is replaced by the q-exponential mappings Eq and eq. This study of representations of the Euclidean quantum algebra and the q-oscillator algebra (not a quantum algebra) leads to summation, integral transform, and q-integral transform identities for q analogs of the Bessel and confluent hypergeometric functions, extending the results of Vilenkin for the q=1 case.

year: 1994-04

title: Flora + Fauna

authors: Apiata, Hāwea

abstract: Visual poetry featured in 'To feel the earth as one's skin: An anthology of Indigenous visual poetry' published by Poem Atlas, London, UK. This poem depicts a koru or an unfurling native fern formed from the words ngāi tipu, referring to plant life (flora), and a tuna or native eel formed from the words ngāi kīrehe, referring to animal life (fauna). Hand-stenciled lettering. Black ink on paper.

text: Flora + Fauna Visual poetry featured in 'To feel the earth as one's skin: An anthology of Indigenous visual poetry' published by Poem Atlas, London, UK. This poem depicts a koru or an unfurling native fern formed from the words ngāi tipu, referring to plant life (flora), and a tuna or native eel formed from the words ngāi kīrehe, referring to animal life (fauna). Hand-stenciled lettering. Black ink on paper.

year: 2024-08-24