title: Identifying invertebrate invasions using morphological and molecular analyses: North American Daphnia ‘pulex’ in New Zealand fresh waters

authors: Duggan, Ian C.

subjects: Biological invasions

abstract: We used a DNA barcoding approach to identify specimens of the Daphnia pulex complex occurring in New Zealand lakes, documenting the establishment of non-indigenous North American Daphnia 'pulex'. Morphological delineation of species in this complex is problematic due to a lack of good morphological traits to distinguish the species, as there is a relatively high degree of morphological stasis within the group through evolutionary time. Accordingly, genetic analyses were used to determine the specific identity and likely geographic origin of this species. Morphologically, individuals most closely resembled Daphnia pulicaria or Daphnia pulex sensu lato, which cannot be separated morphologically. Furthermore, each of these taxa comprises separate species in North America and Europe, despite carrying the same names. We identified individuals using a 658 bp nucleotide portion of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) as North American Daphnia 'pulex', being distinct from European Daphnia pulex sensu stricto and D. pulicaria from Europe or North America. Cellulose allozyme electrophoresis was used to confirm that individuals were not hybrids with D. pulicaria. North American Daphnia 'pulex' in New Zealand were first recorded in New Zealand from South Island lakes that are popular for overseas recreational fishers, indicating a possible source of introduction for this species (e.g. on/in fishing gear). Our study provides an additional example of how genetic techniques can be used for the accurate identification of non-indigenous taxa, particularly when morphological species determination is not possible. The growth of global databases such as GenBank and Barcode of Life Datasystems (BOLD) will further enhance this identification capacity.

text: Identifying invertebrate invasions using morphological and molecular analyses: North American Daphnia ‘pulex’ in New Zealand fresh waters We used a DNA barcoding approach to identify specimens of the Daphnia pulex complex occurring in New Zealand lakes, documenting the establishment of non-indigenous North American Daphnia 'pulex'. Morphological delineation of species in this complex is problematic due to a lack of good morphological traits to distinguish the species, as there is a relatively high degree of morphological stasis within the group through evolutionary time. Accordingly, genetic analyses were used to determine the specific identity and likely geographic origin of this species. Morphologically, individuals most closely resembled Daphnia pulicaria or Daphnia pulex sensu lato, which cannot be separated morphologically. Furthermore, each of these taxa comprises separate species in North America and Europe, despite carrying the same names. We identified individuals using a 658 bp nucleotide portion of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) as North American Daphnia 'pulex', being distinct from European Daphnia pulex sensu stricto and D. pulicaria from Europe or North America. Cellulose allozyme electrophoresis was used to confirm that individuals were not hybrids with D. pulicaria. North American Daphnia 'pulex' in New Zealand were first recorded in New Zealand from South Island lakes that are popular for overseas recreational fishers, indicating a possible source of introduction for this species (e.g. on/in fishing gear). Our study provides an additional example of how genetic techniques can be used for the accurate identification of non-indigenous taxa, particularly when morphological species determination is not possible. The growth of global databases such as GenBank and Barcode of Life Datasystems (BOLD) will further enhance this identification capacity.

year: 2012

title: A study on rhodium and palladium mixed-media sols

authors: Jaine, Jacob Evan

subjects: colloid

abstract: Historically the majority of precious metal sols have been prepared in an aqueous medium, while a much smaller proportion have been prepared in various non‐aqueous solvents. Few however have been prepared in mixtures of the two, this paucity being the raison d’être of this study. The goal therefore was to perform a systematic investigation of the changes in the properties of rhodium and palladium sols generated in mixtures of water and another organic cosolvent across a range of volumetric compositions. Six cosolvents were investigated: methanol, dimethylsulfoxide, acetonitrile, N,N‐dimethylformamide, acetone, and tetrahydrofuran. To stabilise the resulting sols against aggregation four protecting agents were used: poly(vinyl pyrrolidone), poly(vinyl alcohol), poly(acrylic acid), and arabinogalactan, which was a newly‐available polysaccharide extracted from the Western Larch tree. To reduce the metals from their precursor salts, sodium borohydride and hydrazine hydrate were used. The resulting colloids were analysed by Transmission Electron Microscopy (TEM), Photon Correlation Spectroscopy (PCS) and Ultraviolet/Visible Spectrophotometry. The size of the primary particles in the resulting sols was shown by TEM to be inversely proportional to the proportion of cosolvent in which they were generated. A theory was postulated to account for these changes based on temporary stabilisation of the metal nuclei by adsorption of cosolvent molecules. The characteristics of the aggregates observed in the TEM micrographs were shown to be independent of the cosolvent proportion, changing progressively but unpredictably across the composition ranges studied for most systems. This behaviour was believed to be caused by changes in the conformations of the protecting agents, which depended nonlinearly on the composition of the dispersion medium in which they were used. The measurements collected in‐situ by both PCS and UV/Vis were considered to be good indicators of the levels of aggregation observed in the sols ex‐situ by TEM, with any disparities between the two sets of measurements rationalised with relative ease. PCS measurements gave average hydrodynamic diameters of approximately 20 nm – 80 nm for sols generated in purely aqueous dispersion media, depending on the metal and protecting agent used. Infrared spectra were collected of carbon monoxide adsorbed to the surface of the particles of the sols in mixed‐media to determine the effect of the cosolvent proportion on ν(CO)ads. Sols generated for the aforementioned work were found to be of insufficient density for this purpose, so a series of high‐density sols were synthesised especially. Adsorbed CO was successfully detected on rhodium sols in mixtures of water and either MeOH, DMF, DMSO or MeCN. In these cases υ(CO)ads and its intensity decreased as the cosolvent proportion was increased. This behaviour was rationalised by competitive adsorption of the cosolvent molecules onto the surface of the colloidal particles, precluding the adsorption of CO molecules. The consequent decrease in surface coverage was presumed to have lead to a loss of dipolar coupling, affecting the stretching frequency. These data were used to support the theory postulated for the decrease in the average particle size of the sols generated in mixed‐media.

text: A study on rhodium and palladium mixed-media sols Historically the majority of precious metal sols have been prepared in an aqueous medium, while a much smaller proportion have been prepared in various non‐aqueous solvents. Few however have been prepared in mixtures of the two, this paucity being the raison d’être of this study. The goal therefore was to perform a systematic investigation of the changes in the properties of rhodium and palladium sols generated in mixtures of water and another organic cosolvent across a range of volumetric compositions. Six cosolvents were investigated: methanol, dimethylsulfoxide, acetonitrile, N,N‐dimethylformamide, acetone, and tetrahydrofuran. To stabilise the resulting sols against aggregation four protecting agents were used: poly(vinyl pyrrolidone), poly(vinyl alcohol), poly(acrylic acid), and arabinogalactan, which was a newly‐available polysaccharide extracted from the Western Larch tree. To reduce the metals from their precursor salts, sodium borohydride and hydrazine hydrate were used. The resulting colloids were analysed by Transmission Electron Microscopy (TEM), Photon Correlation Spectroscopy (PCS) and Ultraviolet/Visible Spectrophotometry. The size of the primary particles in the resulting sols was shown by TEM to be inversely proportional to the proportion of cosolvent in which they were generated. A theory was postulated to account for these changes based on temporary stabilisation of the metal nuclei by adsorption of cosolvent molecules. The characteristics of the aggregates observed in the TEM micrographs were shown to be independent of the cosolvent proportion, changing progressively but unpredictably across the composition ranges studied for most systems. This behaviour was believed to be caused by changes in the conformations of the protecting agents, which depended nonlinearly on the composition of the dispersion medium in which they were used. The measurements collected in‐situ by both PCS and UV/Vis were considered to be good indicators of the levels of aggregation observed in the sols ex‐situ by TEM, with any disparities between the two sets of measurements rationalised with relative ease. PCS measurements gave average hydrodynamic diameters of approximately 20 nm – 80 nm for sols generated in purely aqueous dispersion media, depending on the metal and protecting agent used. Infrared spectra were collected of carbon monoxide adsorbed to the surface of the particles of the sols in mixed‐media to determine the effect of the cosolvent proportion on ν(CO)ads. Sols generated for the aforementioned work were found to be of insufficient density for this purpose, so a series of high‐density sols were synthesised especially. Adsorbed CO was successfully detected on rhodium sols in mixtures of water and either MeOH, DMF, DMSO or MeCN. In these cases υ(CO)ads and its intensity decreased as the cosolvent proportion was increased. This behaviour was rationalised by competitive adsorption of the cosolvent molecules onto the surface of the colloidal particles, precluding the adsorption of CO molecules. The consequent decrease in surface coverage was presumed to have lead to a loss of dipolar coupling, affecting the stretching frequency. These data were used to support the theory postulated for the decrease in the average particle size of the sols generated in mixed‐media.

year: 2011

title: Early intervention services: Effectively supporting Maori children and their families

authors: Berryman, Mere

subjects: Early Childhood

abstract: This paper examines Early Intervention (EI) service provision from within one Ministry of Education region in New Zealand. It does this in order to better understand what works well and what needs to change if children from Maori families, of Early Childhood age, are to be provided with the most effective EI services. By engaging with Maori families in group-focused interviews-asconversation, and then with their service providers, about their experiences of working together, researchers learned about what could provide effective services for other Maori families in similar situations.

text: Early intervention services: Effectively supporting Maori children and their families This paper examines Early Intervention (EI) service provision from within one Ministry of Education region in New Zealand. It does this in order to better understand what works well and what needs to change if children from Maori families, of Early Childhood age, are to be provided with the most effective EI services. By engaging with Maori families in group-focused interviews-asconversation, and then with their service providers, about their experiences of working together, researchers learned about what could provide effective services for other Maori families in similar situations.

year: 2011