title: Surface Roughening of Platinum Wire: An Electrochemical and Mechanical Approach

authors: Gygax, Stefan Manu

subjects: Surface Roughening

abstract: In order to make implanted electrodes MRI safe several methods have been explored. One of those methods involves increasing AC resistance by roughening the surface of the implanted platinum wires. This thesis explores an electrochemical and a mechanical approach to reliably induce 15 micro meter deep surface defects. The electrochemical approach dissolves the outermost layer of the wire and redeposits a porous layer on the surface that does not grow more than 2 micro meters thick. It is predicted that this layer may be grown to desired thickness if the source of platinum comes from within the solution treatment takes place in rather than the treated wire itself. The mechanical approach induces fatigue cracks that grow predictably and can be controlled to desired size. The limitations are the small amount of wire that may be treated at a time through rotational fatiguing, and the initial quality of the treated wire. High quality wire and an ultrasonic fatigue setup may remedy these limitations.

text: Surface Roughening of Platinum Wire: An Electrochemical and Mechanical Approach In order to make implanted electrodes MRI safe several methods have been explored. One of those methods involves increasing AC resistance by roughening the surface of the implanted platinum wires. This thesis explores an electrochemical and a mechanical approach to reliably induce 15 micro meter deep surface defects. The electrochemical approach dissolves the outermost layer of the wire and redeposits a porous layer on the surface that does not grow more than 2 micro meters thick. It is predicted that this layer may be grown to desired thickness if the source of platinum comes from within the solution treatment takes place in rather than the treated wire itself. The mechanical approach induces fatigue cracks that grow predictably and can be controlled to desired size. The limitations are the small amount of wire that may be treated at a time through rotational fatiguing, and the initial quality of the treated wire. High quality wire and an ultrasonic fatigue setup may remedy these limitations.

year: 2017

title: Are botanical gardens a risk for zooplankton invasions?

authors: Duggan, Ian C.

subjects: botanical gardens

abstract: A number of zooplankton invasions have been linked with the movement of plants to botanical and other public gardens. Although most of these records are historical, several recent examples indicate that aquatic fauna may still be transported by plant movements among gardens, or that there are unrecognised long-standing established populations in garden ponds around the world. We sampled 40 ponds from 10 gardens, in the United Kingdom and United States, to determine whether there is a high prevalence of non-indigenous zooplankton in garden ponds that could spread more widely if provided opportunity. No non-indigenous species were recorded from any of the gardens visited. We conclude that most well-established gardens do not pose a major threat for zooplankton invasions, mainly due to the destruction of ponds and associated populations through time, which apparently occurs commonly. In addition, ponds are regularly cleaned, insecticides are used on plants that may enter the water, and small fish are frequently added to conservatory ponds, further reducing the probability of zooplankton survival. Extirpation of populations may be occurring at a greater rate than re-introduction, due to greater restrictions on movement of plants, while the increasing focus on ex-situ conservation and science rather than aesthetics by botanical gardens means that fewer aquatic plants are being moved.

text: Are botanical gardens a risk for zooplankton invasions? A number of zooplankton invasions have been linked with the movement of plants to botanical and other public gardens. Although most of these records are historical, several recent examples indicate that aquatic fauna may still be transported by plant movements among gardens, or that there are unrecognised long-standing established populations in garden ponds around the world. We sampled 40 ponds from 10 gardens, in the United Kingdom and United States, to determine whether there is a high prevalence of non-indigenous zooplankton in garden ponds that could spread more widely if provided opportunity. No non-indigenous species were recorded from any of the gardens visited. We conclude that most well-established gardens do not pose a major threat for zooplankton invasions, mainly due to the destruction of ponds and associated populations through time, which apparently occurs commonly. In addition, ponds are regularly cleaned, insecticides are used on plants that may enter the water, and small fish are frequently added to conservatory ponds, further reducing the probability of zooplankton survival. Extirpation of populations may be occurring at a greater rate than re-introduction, due to greater restrictions on movement of plants, while the increasing focus on ex-situ conservation and science rather than aesthetics by botanical gardens means that fewer aquatic plants are being moved.

year: 2011

title: Te whakahuatanga i te reo Māori: Kua ahatia e tātou i roto i ngā tau 100 kua hipa nei? (The pronunciation of Māori: What have we done to it in the last 100 Years?)

authors: Harlow, Ray

subjects: Te reo Māori

abstract: In the words of the proverb: 'The land remains, but humankind vanishes.' One should perhaps extend this to read: 'The land remains, humankind vanishes, and language changes.' For languages are old, handed down from one generation to another, but no matter what, they change. Present-day English is not Shakespeare's or Chaucer's language. The pronunciation has changed, new words have entered the language, some words have been lost, the grammar is now different. Māori is like that as well. Over the last two centuries, many aspects of the language have become different. Many words have been borrowed from English, and become part of the language. Many new words have been created in recent years to accommodate the new topics now being spoken about in Māori. Many words have changed their meaning, e.g., 'pūtea' originally a type of basket, but now a 'fund', source of money. In the grammar, there are now constructions being used which were not correct in earlier centuries.So far as the pronunciation is concerned, how is one to observe its development? That is the substance of a research project which has only just now begun, and it is the purpose of this paper to explain the nature of that research and show some of the preliminary findings. Hence the title: The pronunciation of Māori: What have we done to it in the last 100 years? The project is supported by the Marsden Research Fund.

text: Te whakahuatanga i te reo Māori: Kua ahatia e tātou i roto i ngā tau 100 kua hipa nei? (The pronunciation of Māori: What have we done to it in the last 100 Years?) In the words of the proverb: 'The land remains, but humankind vanishes.' One should perhaps extend this to read: 'The land remains, humankind vanishes, and language changes.' For languages are old, handed down from one generation to another, but no matter what, they change. Present-day English is not Shakespeare's or Chaucer's language. The pronunciation has changed, new words have entered the language, some words have been lost, the grammar is now different. Māori is like that as well. Over the last two centuries, many aspects of the language have become different. Many words have been borrowed from English, and become part of the language. Many new words have been created in recent years to accommodate the new topics now being spoken about in Māori. Many words have changed their meaning, e.g., 'pūtea' originally a type of basket, but now a 'fund', source of money. In the grammar, there are now constructions being used which were not correct in earlier centuries.So far as the pronunciation is concerned, how is one to observe its development? That is the substance of a research project which has only just now begun, and it is the purpose of this paper to explain the nature of that research and show some of the preliminary findings. Hence the title: The pronunciation of Māori: What have we done to it in the last 100 years? The project is supported by the Marsden Research Fund.

year: 2005-05