title: Valuing externalities from water supply: status quo, choice complexity, and individual random effects in panel kernel logit analysis of choice experiments

authors: Scarpa, Riccardo

subjects: choice experiments

abstract: Choice experiments are often implemented with choice sets including one alternative depicting the status quo. Utility from status quo is experienced by the respondent, while utility associated with experimentally designed hypothetical alternatives is only conjectured by respondents. The effects of explicitly accounting for such a difference in the econometric analysis of the data are often unreported, or limited to fitting a 'status quo' constant. The paper proposes a model that explicitly accounts for these effects and attempts their decomposition using data from two choice modelling exercises designed to value the provision of environmental goods. Preferences for change versus status quo are explored with standard specifications along with a less usually applied error component analysis via mixed logit. The results suggest that alternatives offering changes from status quo do not share the same preference structure as the status quo alternative, and that estimates of spread parameters in zero-mean error components can be decomposed conditional on respondents' socio-economic characteristics. It is argued that these findings have implications for practitioners and their stance towards the strategies for the econometric analysis of choice modelling data for the purpose of valuation.

text: Valuing externalities from water supply: status quo, choice complexity, and individual random effects in panel kernel logit analysis of choice experiments Choice experiments are often implemented with choice sets including one alternative depicting the status quo. Utility from status quo is experienced by the respondent, while utility associated with experimentally designed hypothetical alternatives is only conjectured by respondents. The effects of explicitly accounting for such a difference in the econometric analysis of the data are often unreported, or limited to fitting a 'status quo' constant. The paper proposes a model that explicitly accounts for these effects and attempts their decomposition using data from two choice modelling exercises designed to value the provision of environmental goods. Preferences for change versus status quo are explored with standard specifications along with a less usually applied error component analysis via mixed logit. The results suggest that alternatives offering changes from status quo do not share the same preference structure as the status quo alternative, and that estimates of spread parameters in zero-mean error components can be decomposed conditional on respondents' socio-economic characteristics. It is argued that these findings have implications for practitioners and their stance towards the strategies for the econometric analysis of choice modelling data for the purpose of valuation.

year: 2007

title: A sedimentological study of three saline lakes in the Dry Valleys of Victoria Land, Antarctica

authors: Gumbley, John Watson

subjects: Sediments

abstract: The Dry Valley region of Victoria Land is the largest ice-free area in Antarctica. Within the frigid arid environment of the Dry Valleys, where the mean annual air temperature is -20℃, there are several permanently ice-covered, amictic, saline lakes occupying undrained bedrock depressions. Three of these lakes, namely Lakes Vanda, Bonney and Joyce, have been studied with the aim of determining the nature of their bottom sediments and relating the stratigraphy of bottom sediment cores to Holocene climatic fluctuations. These lakes have an area of 0.8 to 5.2 km², are from 35 to 68m in maximum depth and have an ice-cover 3 to 4m thick. The lakes are chemically and thermally stratified and receive their water from meltwater streams draining the local glaciers.

The bottom sediments consist of detrital sands and silts, chemical precipitates and organic material. The detrital sediments consist of feldspar and quartz with smaller quantities of hornblende, augite, hypersthene and mica that are derived locally from the rocks exposed on the adjacent valley sides. These sediments are mainly wind-transported or, to a lesser extent, river-transported into the lakes. The wind derived sediments are either blown onto the lake-ice, where they eventually sink to the lake-floor, or they are blown into the moat developed about the shores of the lake in summer. The chemical precipitates consist mainly of gypsum, halite, aragonite and calcite whose constituent elements were derived from meltwater streams discharging into the lakes; however Lake Bonney also received dissolved solids of marine origin about 300,000 years B.P. and 1,200 years B.P.

From the sequence of chemical precipitate - rich bands and grain-size cycles in cores from Lakes Vanda and Joyce, together with the stratigraphy in the Lake Bonney cores, a sequence of climatic fluctuations is inferred. Colder climatic phases are most probably associated with periods of low lake-level during which chemical precipitates formed following the concentration of brines under frigid evaporitic conditions. At these times the sediment input from meltwater streams was low because of the locking-up of water in valley glaciers, and the main source of sediment would probably then be wind-derived. 

U/Th dating of the chemical precipitates has provided an absolute record of past climatic changes which indicate that the major glacier systems in the Dry Valley region were nonsynchronous. Low lake levels occurred in Lake Vanda some 2,000 and 5,500 years B.P. and on at least four earlier occasions. Sediment cores from Lake Joyce indicate a period of low lake-level about 3,000 years B.P. The Lake Bonney cores suggest periods of low lake-level occurred following each of the marine incursions into the valley (300,000 and 1,200 years B.P.) and that the advance of the Taylor Glacier into the Bonney Basin at least 10,000 years B.P. probably coincided with the Taylor I Glaciation. Frigid evaporitic conditions have continued to operate in Lake Bonney since 1,200 years B.P. with halite crystals forming on the lake-floor. However, the lake-level has been steadily rising over the last 500 years.

text: A sedimentological study of three saline lakes in the Dry Valleys of Victoria Land, Antarctica The Dry Valley region of Victoria Land is the largest ice-free area in Antarctica. Within the frigid arid environment of the Dry Valleys, where the mean annual air temperature is -20℃, there are several permanently ice-covered, amictic, saline lakes occupying undrained bedrock depressions. Three of these lakes, namely Lakes Vanda, Bonney and Joyce, have been studied with the aim of determining the nature of their bottom sediments and relating the stratigraphy of bottom sediment cores to Holocene climatic fluctuations. These lakes have an area of 0.8 to 5.2 km², are from 35 to 68m in maximum depth and have an ice-cover 3 to 4m thick. The lakes are chemically and thermally stratified and receive their water from meltwater streams draining the local glaciers.

The bottom sediments consist of detrital sands and silts, chemical precipitates and organic material. The detrital sediments consist of feldspar and quartz with smaller quantities of hornblende, augite, hypersthene and mica that are derived locally from the rocks exposed on the adjacent valley sides. These sediments are mainly wind-transported or, to a lesser extent, river-transported into the lakes. The wind derived sediments are either blown onto the lake-ice, where they eventually sink to the lake-floor, or they are blown into the moat developed about the shores of the lake in summer. The chemical precipitates consist mainly of gypsum, halite, aragonite and calcite whose constituent elements were derived from meltwater streams discharging into the lakes; however Lake Bonney also received dissolved solids of marine origin about 300,000 years B.P. and 1,200 years B.P.

From the sequence of chemical precipitate - rich bands and grain-size cycles in cores from Lakes Vanda and Joyce, together with the stratigraphy in the Lake Bonney cores, a sequence of climatic fluctuations is inferred. Colder climatic phases are most probably associated with periods of low lake-level during which chemical precipitates formed following the concentration of brines under frigid evaporitic conditions. At these times the sediment input from meltwater streams was low because of the locking-up of water in valley glaciers, and the main source of sediment would probably then be wind-derived. 

U/Th dating of the chemical precipitates has provided an absolute record of past climatic changes which indicate that the major glacier systems in the Dry Valley region were nonsynchronous. Low lake levels occurred in Lake Vanda some 2,000 and 5,500 years B.P. and on at least four earlier occasions. Sediment cores from Lake Joyce indicate a period of low lake-level about 3,000 years B.P. The Lake Bonney cores suggest periods of low lake-level occurred following each of the marine incursions into the valley (300,000 and 1,200 years B.P.) and that the advance of the Taylor Glacier into the Bonney Basin at least 10,000 years B.P. probably coincided with the Taylor I Glaciation. Frigid evaporitic conditions have continued to operate in Lake Bonney since 1,200 years B.P. with halite crystals forming on the lake-floor. However, the lake-level has been steadily rising over the last 500 years.

year: 1975

title: Nga taonga o Te Urewera

authors: Te Awekotuku, Ngahuia

subjects: Maori

abstract: This report sets out to establish that Te Urewera and Tuhoe - the place, the people -
are synonymous. It is argued by two discrete approaches - cultural property and the
significance of place. These are both enmeshed in the Tuhoe concept of
matemateaone, which is defined and demonstrated throughout the text. Issues of
Tuhoe heritage and cultural property are positioned within the international
indigenous context, and considered in detail with reference to the United Nations
Report on the Protection of the Heritage of Indigenous Peoples tabled in June 1995.
A Tuhoe response to the nine sections of this document form the basis of this
submission, as they clearly reflect the intentions and principles that configure the
articles of the Treaty of Waitangi.

text: Nga taonga o Te Urewera This report sets out to establish that Te Urewera and Tuhoe - the place, the people -
are synonymous. It is argued by two discrete approaches - cultural property and the
significance of place. These are both enmeshed in the Tuhoe concept of
matemateaone, which is defined and demonstrated throughout the text. Issues of
Tuhoe heritage and cultural property are positioned within the international
indigenous context, and considered in detail with reference to the United Nations
Report on the Protection of the Heritage of Indigenous Peoples tabled in June 1995.
A Tuhoe response to the nine sections of this document form the basis of this
submission, as they clearly reflect the intentions and principles that configure the
articles of the Treaty of Waitangi.

year: 2003-08