title: Effects of a small-bladed macroalgal canopy on benthic boundary layer dynamics: implications for nutrient transport

authors: Kregting, Louise T.

subjects: macroalgae

abstract: Field and laboratory velocity profiles were used to quantify boundary layer dynamics within communities of a small (<0.2 m tall), dense canopy-forming seaweed Adamsiella chauvinii (Rhodophyta) in a soft-sediment habitat and to examine the role of hydrodynamics in modulating nutrient supply. At the ‘canopy scale’ there was a mixing layer at the fluid−canopy interface where turbulent kinetic energy was greatest, potentially enhancing nutrient uptake in this region. In the lower half of the canopy, a drag-dominated area of very low water velocity (<0.01 m s−1) occurred. Spectral analysis revealed a reduction in energy within the canopy of around 1 Hz. The hydrodynamic parameters obtained from flume measurements were in good agreement with those recorded in the field. To understand the implications of the hydrodynamic environment on nutrient uptake, a flushing ratio was developed that compares the time for macroalgae to remove all nutrients from the canopy volume relative to the timescale for flushing. Results suggest that when nutrient demand is low, the canopy is well flushed and not mass-transfer limited. However when nutrient demand is high, the canopy can deplete nutrients more quickly than they can be replenished by ambient flows and are potentially mass-transfer limited.

text: Effects of a small-bladed macroalgal canopy on benthic boundary layer dynamics: implications for nutrient transport Field and laboratory velocity profiles were used to quantify boundary layer dynamics within communities of a small (<0.2 m tall), dense canopy-forming seaweed Adamsiella chauvinii (Rhodophyta) in a soft-sediment habitat and to examine the role of hydrodynamics in modulating nutrient supply. At the ‘canopy scale’ there was a mixing layer at the fluid−canopy interface where turbulent kinetic energy was greatest, potentially enhancing nutrient uptake in this region. In the lower half of the canopy, a drag-dominated area of very low water velocity (<0.01 m s−1) occurred. Spectral analysis revealed a reduction in energy within the canopy of around 1 Hz. The hydrodynamic parameters obtained from flume measurements were in good agreement with those recorded in the field. To understand the implications of the hydrodynamic environment on nutrient uptake, a flushing ratio was developed that compares the time for macroalgae to remove all nutrients from the canopy volume relative to the timescale for flushing. Results suggest that when nutrient demand is low, the canopy is well flushed and not mass-transfer limited. However when nutrient demand is high, the canopy can deplete nutrients more quickly than they can be replenished by ambient flows and are potentially mass-transfer limited.

year: 2011

title: Consumers WTP for wine with certified origin: preliminary results from latent classes based on attitudinal responses

authors: Scarpa, Riccardo

subjects: latent class attitudinal model

abstract: This article investigates preference heterogeneity of wine consumers by using latent class models based on attitudinal questions. Such responses turn out to be an important source of additional information when the goal is to identify different groups of people with a similar wine preference structure. We assume that preferences are latent and the responses to attitudinal questions are the visible effect of this latent heterogeneity. In this study evidence is found of four different classes of respondents with similar response patterns. We focus on preferences for a well-known wine, the Prosecco, and use a sample of the population in the area of production. For each preference-class we estimate a class-specific WTP (willingness to pay) equation for this wine, so as to estimate the class responsiveness of WTP to various determinants. Estimates for a four-class model are discussed in detail to illustrate the potential of this approach in characterizing the preferences of local consumers for the two most common certifications of origin.

text: Consumers WTP for wine with certified origin: preliminary results from latent classes based on attitudinal responses This article investigates preference heterogeneity of wine consumers by using latent class models based on attitudinal questions. Such responses turn out to be an important source of additional information when the goal is to identify different groups of people with a similar wine preference structure. We assume that preferences are latent and the responses to attitudinal questions are the visible effect of this latent heterogeneity. In this study evidence is found of four different classes of respondents with similar response patterns. We focus on preferences for a well-known wine, the Prosecco, and use a sample of the population in the area of production. For each preference-class we estimate a class-specific WTP (willingness to pay) equation for this wine, so as to estimate the class responsiveness of WTP to various determinants. Estimates for a four-class model are discussed in detail to illustrate the potential of this approach in characterizing the preferences of local consumers for the two most common certifications of origin.

year: 2009

title: The processes involved in formulating a marae-based Māori language regeneration plan for Whakamārama marae: Outline, analysis and evaluation

authors: Lewis, Roger

subjects: New Zealand

abstract: We provide here a criterion referenced evaluation of the processes involved in the creation of a Māori language regeneration strategy for Whakamārama marae. Working voluntarily and often under difficult circumstances, core group members demonstrated that they possessed the essential characteristics of commitment, motivation and determination. In addition, they demonstrated the willingness and ability to use existing skills and knowledge effectively and to develop further skills and knowledge as the project proceeded. Perhaps most important, they developed a caring and effective working culture. However, the weaknesses of the project included a lack of preparation and planning prior to the commencement of the project which led to delays in producing outcomes and some loss of momentum. This also led, indirectly, to the views of two or three members of the core group being overrepresented in the language planning goals. We believe that the information and analysis provided here are likely to be of interest to any language community involved in micro-level language regeneration activities of a similar type.

text: The processes involved in formulating a marae-based Māori language regeneration plan for Whakamārama marae: Outline, analysis and evaluation We provide here a criterion referenced evaluation of the processes involved in the creation of a Māori language regeneration strategy for Whakamārama marae. Working voluntarily and often under difficult circumstances, core group members demonstrated that they possessed the essential characteristics of commitment, motivation and determination. In addition, they demonstrated the willingness and ability to use existing skills and knowledge effectively and to develop further skills and knowledge as the project proceeded. Perhaps most important, they developed a caring and effective working culture. However, the weaknesses of the project included a lack of preparation and planning prior to the commencement of the project which led to delays in producing outcomes and some loss of momentum. This also led, indirectly, to the views of two or three members of the core group being overrepresented in the language planning goals. We believe that the information and analysis provided here are likely to be of interest to any language community involved in micro-level language regeneration activities of a similar type.

year: 2008