title: A novel ‘FlocDrifter’ platform for observing flocculation and turbulence processes in a Lagrangian frame of reference

authors: MacDonald, Iain T.

abstract: A novel drifter platform was used to measure the properties of aggregated particles called flocs—a key component of sediment transport in muddy environments. Also concurrently measured were turbulence, suspended sediment concentration (SSC), velocity, and salinity in both Lagrangian and Eulerian frames of reference. In Lagrangian mode the system performed well in a heavily sediment-laden river, providing measurements over a large spatial scale. The platform navigated itself through a complex geometry encompassing many bends and significant depth changes. Observed velocities relative to the drifter and salinities indicated that the drifter motion was almost Lagrangian with minimal slippage between the drifter and the water motion. The small amount of slippage that did occur was sufficient to ensure that the drifter oriented itself into the oncoming flow. 
High-quality in situ images of flocs were collected using a high-magnification floc camera (FlocCam). An automatic image analysis routine was developed to identify and characterize flocs within each FlocCam image, employing an artificial neural network (ANN) to ensure that only in-focus particles were included in the analyses. The results indicated that the FlocCam system had an upper working SSC limit of around 350–400 mg L⁻¹. 
The SSC estimates show that the drifters encountered considerable variability as they were advected downstream; however, concentrations predominantly remained under the image processing threshold of 350–400 mg L⁻¹. The system captured the evolution of floc characteristics over short spatial scales (hundreds of meters). The median floc size (d₅₀) was found to be positively correlated with SSC (r² = 0.5). A comparison between Eulerian and Lagrangian floc histories can then be used to evaluate the role of antecedent conditions within the flocculation process.

text: A novel ‘FlocDrifter’ platform for observing flocculation and turbulence processes in a Lagrangian frame of reference A novel drifter platform was used to measure the properties of aggregated particles called flocs—a key component of sediment transport in muddy environments. Also concurrently measured were turbulence, suspended sediment concentration (SSC), velocity, and salinity in both Lagrangian and Eulerian frames of reference. In Lagrangian mode the system performed well in a heavily sediment-laden river, providing measurements over a large spatial scale. The platform navigated itself through a complex geometry encompassing many bends and significant depth changes. Observed velocities relative to the drifter and salinities indicated that the drifter motion was almost Lagrangian with minimal slippage between the drifter and the water motion. The small amount of slippage that did occur was sufficient to ensure that the drifter oriented itself into the oncoming flow. 
High-quality in situ images of flocs were collected using a high-magnification floc camera (FlocCam). An automatic image analysis routine was developed to identify and characterize flocs within each FlocCam image, employing an artificial neural network (ANN) to ensure that only in-focus particles were included in the analyses. The results indicated that the FlocCam system had an upper working SSC limit of around 350–400 mg L⁻¹. 
The SSC estimates show that the drifters encountered considerable variability as they were advected downstream; however, concentrations predominantly remained under the image processing threshold of 350–400 mg L⁻¹. The system captured the evolution of floc characteristics over short spatial scales (hundreds of meters). The median floc size (d₅₀) was found to be positively correlated with SSC (r² = 0.5). A comparison between Eulerian and Lagrangian floc histories can then be used to evaluate the role of antecedent conditions within the flocculation process.

year: 2015

title: Focus groups as sites of influential interaction: Building communicative self-efficacy and effecting attitudinal change in discussing controversial topics

authors: Zorn, Theodore E.

subjects: focus groups

abstract: Although most focus group theorists consider interaction to be a defining feature of focus groups, the influence that occurs through this interaction has been under-theorized. We argue that two important forms of influence may occur: influence on people's beliefs about the substantive issues under discussion and influence on self-efficacy beliefs. As a result of such influence, focus groups provide a learning context that may facilitate empowerment of participants through the development of communicative self-efficacy as they struggle over constructing and sharing understandings of controversial issues. As part of a larger research project on dialogues about science, we present a case study that puts qualitatively analyzed transcripts of interaction and quantitative self-report measures into empirical conversation. The case study demonstrated that focus group participants were influenced in two important ways: participation and interaction led to increased participant confidence and motivation towards participating in public dialogues and to the construction, modification, and contestation of attitudes toward science, scientists, and biotechnology. Findings suggest that scholars should rethink their rationales for and use of the focus group as just a method of data collection and reconsider and explore alternative ways of presenting focus group results.

text: Focus groups as sites of influential interaction: Building communicative self-efficacy and effecting attitudinal change in discussing controversial topics Although most focus group theorists consider interaction to be a defining feature of focus groups, the influence that occurs through this interaction has been under-theorized. We argue that two important forms of influence may occur: influence on people's beliefs about the substantive issues under discussion and influence on self-efficacy beliefs. As a result of such influence, focus groups provide a learning context that may facilitate empowerment of participants through the development of communicative self-efficacy as they struggle over constructing and sharing understandings of controversial issues. As part of a larger research project on dialogues about science, we present a case study that puts qualitatively analyzed transcripts of interaction and quantitative self-report measures into empirical conversation. The case study demonstrated that focus group participants were influenced in two important ways: participation and interaction led to increased participant confidence and motivation towards participating in public dialogues and to the construction, modification, and contestation of attitudes toward science, scientists, and biotechnology. Findings suggest that scholars should rethink their rationales for and use of the focus group as just a method of data collection and reconsider and explore alternative ways of presenting focus group results.

year: 2006

title: Te Ahurei a Rangatahi sexual health programme: An evaluation

authors: Nikora, Linda Waimarie

subjects: youth

abstract: The Maori and Psychology Research Unit was engaged in August 2001 to evaluate a
sexual health programme delivered by Te Ahurei a Rangatahi. Established in 1997,
Te Ahurei a Rangatahi is a community based charitable trust that delivers a variety of
programmes to Rangatahi.

text: Te Ahurei a Rangatahi sexual health programme: An evaluation The Maori and Psychology Research Unit was engaged in August 2001 to evaluate a
sexual health programme delivered by Te Ahurei a Rangatahi. Established in 1997,
Te Ahurei a Rangatahi is a community based charitable trust that delivers a variety of
programmes to Rangatahi.

year: 2001-12-01