title: Contorted stratification with clay lobes in volcanic ash beds, Raglan-Hamilton region, New Zealand

authors: Tonkin, Philip J.

abstract: Contorted stratification in basal volcanic ash beds of the Pleistocene Hamilton Ash Formation incorporates halloysitic clay lobes which project upward into a bed of predominantly allophanic material. The forms produced are similar to convolute laminations described in other marine and non-marine sedimentary sequences.
The halloysitic clay lobes have been described previously as concretions and as the products of differential weathering processes.
A third hypothesis is proposed to explain the formation of the clay lobes and associated contorted stratification of these basal ash beds, namely, that the beds were deformed by plastic flowage of halloysitic clay into a sensitive allophanic bed. This deformation was possibly a result of water-saturated beds rapidly losing strength as a result of cyclic reversals of stress and strain produced by earthquake shock waves.

text: Contorted stratification with clay lobes in volcanic ash beds, Raglan-Hamilton region, New Zealand Contorted stratification in basal volcanic ash beds of the Pleistocene Hamilton Ash Formation incorporates halloysitic clay lobes which project upward into a bed of predominantly allophanic material. The forms produced are similar to convolute laminations described in other marine and non-marine sedimentary sequences.
The halloysitic clay lobes have been described previously as concretions and as the products of differential weathering processes.
A third hypothesis is proposed to explain the formation of the clay lobes and associated contorted stratification of these basal ash beds, namely, that the beds were deformed by plastic flowage of halloysitic clay into a sensitive allophanic bed. This deformation was possibly a result of water-saturated beds rapidly losing strength as a result of cyclic reversals of stress and strain produced by earthquake shock waves.

year: 1970

title: No evidence for a culturable bacterial tetrodotoxin producer in Pleurobranchaea maculata (Gastropoda: Pleurobranchidae) and Stylochoplana sp. (Platyhelminthes: Polycladida)

authors: Salvitti, Lauren R.

subjects: bacteria

abstract: Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography—mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely.

text: No evidence for a culturable bacterial tetrodotoxin producer in Pleurobranchaea maculata (Gastropoda: Pleurobranchidae) and Stylochoplana sp. (Platyhelminthes: Polycladida) Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography—mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely.

year: 2015-01-28

title: Representations of diversity in the revised New Zealand PictureBook Collection

authors: Daly, Nicola

subjects: picturebooks

abstract: Collections of children’s literature are used for a range of reasons including preservation, record keeping, and more recently the encouragement of intercultural understanding. Both the signifi- cance of learning about other cultures and the importance of children seeing themselves reflected in the books that they read have been discussed extensively. In 2010, the New Zealand PictureBook Collection (NZPBC) was developed in order to create a resource that reflected New Zealand national identity. In 2015 the NZPBC was revised and this article presents a visual and textual analysis of the diversity present in the sixty books nomi- nated through the lens of critical multicultural analysis, using four variables. Findings indicate considerable diversity is present in the collection in terms of representations of ethnicity and family; less so for representations of disability and languages.

text: Representations of diversity in the revised New Zealand PictureBook Collection Collections of children’s literature are used for a range of reasons including preservation, record keeping, and more recently the encouragement of intercultural understanding. Both the signifi- cance of learning about other cultures and the importance of children seeing themselves reflected in the books that they read have been discussed extensively. In 2010, the New Zealand PictureBook Collection (NZPBC) was developed in order to create a resource that reflected New Zealand national identity. In 2015 the NZPBC was revised and this article presents a visual and textual analysis of the diversity present in the sixty books nomi- nated through the lens of critical multicultural analysis, using four variables. Findings indicate considerable diversity is present in the collection in terms of representations of ethnicity and family; less so for representations of disability and languages.

year: 2017