title: Experiential learning: A narrative of a community dance field trip

authors: Buck, Ralph

abstract: In this paper, we offer a co-constructed narrative of experiential learning in the context of a community dance trip undertaken by tertiary students. We describe the unfolding experiences of a weekend field trip and reflect on community dance practices and values with a view towards articulating a shared vision for community dance. A framework for community dance (Kuppers, 2006; Peppiatt, 1996) provides a context for the students’ learning and for situating our understandings of the interrelationships between art, education, politics, society and environment. Literature on community dance practice and from sociology, experiential learning, and environmental and cultural education provides direction as we interpret our experiences. While this paper is presented as a co- constructed narrative based on our observations during the field trip, we also include comments made by students, along with reflective interludes as we discuss the field trip in relation to dance education.

text: Experiential learning: A narrative of a community dance field trip In this paper, we offer a co-constructed narrative of experiential learning in the context of a community dance trip undertaken by tertiary students. We describe the unfolding experiences of a weekend field trip and reflect on community dance practices and values with a view towards articulating a shared vision for community dance. A framework for community dance (Kuppers, 2006; Peppiatt, 1996) provides a context for the students’ learning and for situating our understandings of the interrelationships between art, education, politics, society and environment. Literature on community dance practice and from sociology, experiential learning, and environmental and cultural education provides direction as we interpret our experiences. While this paper is presented as a co- constructed narrative based on our observations during the field trip, we also include comments made by students, along with reflective interludes as we discuss the field trip in relation to dance education.

year: 2015

title: Pressure screening studies with wood pulp

authors: Weeds, Zuben

subjects: Wood-pulp Refining Separation

abstract: Pressure screening is used in paper making to separate components of a wood pulp slurry (water, wood fibre and solid contaminant material) and to concentrate the wood fibre. The complex solid-liquid and solid-solid mechanisms involved in pressure screening are still poorly understood. This thesis reviews the literature on pressure screening mechanisms and highlights the problems in the models used to describe pressure screening. 
Two models, based on well-mixed tanks in series, are developed to describe reject thickening behaviour of long and short screens. The first model uses a single one row of tanks to model steady flow from feed to accept and from feed to reject streams of a screen. A back-flow model, which had two rows of well-mixed tanks, one for the feedside and another for the accept-side of the screen, was also developed. The passage ratio for back-flow of fibre PB was estimated numerically by deducing the passage ratio for forward-flow of fibre PF. The model showed that PB can decrease more quickly than PF when feed consistency increases, even when overall passage ratio Pp remains constant. 
A small industrial pressure screen (diameter 203 mm, length 220 mm) was used to investigate the effect of screen length Ls and feed consistency Cf on pressure screening performance. The effects of pulp type ( eucalypt for short fibre and pine kraft pulp for short fibre), feed consistency (from 0.005% to 2% compared to approximately 1 % in industrial plants), screen length and placement along the length of the screen, rotor type (bump or step), and screen hole shape (round holes or slots) were investigated. Measurements of pulp consistency in the feed, reject and accept streams under different processing conditions were used to assess the screen models developed. Screening behaviour of screens less than 220 mm was studied extensively for the first time. 
The tanks-in-series model showed that the effect of screen length on reject thickening could be described as well-mixed tanks in series with plug flow behaviour when the screen was modelled as 100 tanks. The reject thickening factor T decreased semilogarithmically when number of tanks was decreased but increased slightly when the number of tanks was increased. . Reject thickening factor decreases when a screen with 1-mm hole is shortened from 220 mm to 27 mm. This reduction can be attributed mainly to the flow regime changing from plug to mixed flow.
The maximum volumetric accept flow rate Qmax decreased by approximately 30 % when a 55-mm screen section was moved from the feed end to the reject end. 1bis decrease in Qmax was consistent with an axial decrease in relative speed ( difference between rotor tip and pulp suspension in the feed annulus), along with an estimated 33% reduction in the negative pressure pulse PNP along the screen. Overall fibre passage ratio PP also decreased when the screen section was moved to the reject end, or when pulp was accelerated in a feed chamber upstream of the feed annulus. 
The three distinct regions and two critical feed consistencies observed when Cr increased from 0.005% to 2% are postulated to indicate when fibre accumulation on the feed and accept sides of the screen produces screen plugging. The critical Cr for the accept side is about ten times greater than that for the feed side due mainly to the fact that the conical holes have a larger diameter on the accept side so more fibre must accumulate before backflow is hindered. In Region 1 ( crowding number < 1 ), reject thickening is independent of feed consistency and remains constant regardless of rotor type (bump or step) and screen type (smooth holes or contoured slots). In Region 2 (1< crowding number< 60), reject thickening decreases with feed consistency. In Region 3 (crowding number > 60), reject thickening either . decreases with feed consistency or remains constant depending on the ratio of forward to back-flushing flow exhibited by the rotor and as predicted by the two-tanks in series model. For the step rotor with a flow ratio of 2:1 reject thickening is constant with feed consistency regardless of screen type. For the bump rotor with a flow ratio of 5: 1 reject thickening decreases with feed consistency regardless of the screen type.
Fibre-length fractionation index <I> increased with increasing Cr to a maximum at about Ct=0.7% when using a 1-mm smooth-holed screen with a bump rotor or at Ct=2% for a 2.4-mm smooth-holed screen. Fractionation index then decreased with increasing Cf. 
It is recommended that the back-flow model be further developed so that the volumetric flow ratio (ratio of forward flow to back flow) can be calculated from a residence time distribution. It is also recommended that fibre-length fractionation be attempted at various positions along the screen for medium consistency pulp (Cr of 8 to 12%) using unconventionally large holes (3-5 mm).

text: Pressure screening studies with wood pulp Pressure screening is used in paper making to separate components of a wood pulp slurry (water, wood fibre and solid contaminant material) and to concentrate the wood fibre. The complex solid-liquid and solid-solid mechanisms involved in pressure screening are still poorly understood. This thesis reviews the literature on pressure screening mechanisms and highlights the problems in the models used to describe pressure screening. 
Two models, based on well-mixed tanks in series, are developed to describe reject thickening behaviour of long and short screens. The first model uses a single one row of tanks to model steady flow from feed to accept and from feed to reject streams of a screen. A back-flow model, which had two rows of well-mixed tanks, one for the feedside and another for the accept-side of the screen, was also developed. The passage ratio for back-flow of fibre PB was estimated numerically by deducing the passage ratio for forward-flow of fibre PF. The model showed that PB can decrease more quickly than PF when feed consistency increases, even when overall passage ratio Pp remains constant. 
A small industrial pressure screen (diameter 203 mm, length 220 mm) was used to investigate the effect of screen length Ls and feed consistency Cf on pressure screening performance. The effects of pulp type ( eucalypt for short fibre and pine kraft pulp for short fibre), feed consistency (from 0.005% to 2% compared to approximately 1 % in industrial plants), screen length and placement along the length of the screen, rotor type (bump or step), and screen hole shape (round holes or slots) were investigated. Measurements of pulp consistency in the feed, reject and accept streams under different processing conditions were used to assess the screen models developed. Screening behaviour of screens less than 220 mm was studied extensively for the first time. 
The tanks-in-series model showed that the effect of screen length on reject thickening could be described as well-mixed tanks in series with plug flow behaviour when the screen was modelled as 100 tanks. The reject thickening factor T decreased semilogarithmically when number of tanks was decreased but increased slightly when the number of tanks was increased. . Reject thickening factor decreases when a screen with 1-mm hole is shortened from 220 mm to 27 mm. This reduction can be attributed mainly to the flow regime changing from plug to mixed flow.
The maximum volumetric accept flow rate Qmax decreased by approximately 30 % when a 55-mm screen section was moved from the feed end to the reject end. 1bis decrease in Qmax was consistent with an axial decrease in relative speed ( difference between rotor tip and pulp suspension in the feed annulus), along with an estimated 33% reduction in the negative pressure pulse PNP along the screen. Overall fibre passage ratio PP also decreased when the screen section was moved to the reject end, or when pulp was accelerated in a feed chamber upstream of the feed annulus. 
The three distinct regions and two critical feed consistencies observed when Cr increased from 0.005% to 2% are postulated to indicate when fibre accumulation on the feed and accept sides of the screen produces screen plugging. The critical Cr for the accept side is about ten times greater than that for the feed side due mainly to the fact that the conical holes have a larger diameter on the accept side so more fibre must accumulate before backflow is hindered. In Region 1 ( crowding number < 1 ), reject thickening is independent of feed consistency and remains constant regardless of rotor type (bump or step) and screen type (smooth holes or contoured slots). In Region 2 (1< crowding number< 60), reject thickening decreases with feed consistency. In Region 3 (crowding number > 60), reject thickening either . decreases with feed consistency or remains constant depending on the ratio of forward to back-flushing flow exhibited by the rotor and as predicted by the two-tanks in series model. For the step rotor with a flow ratio of 2:1 reject thickening is constant with feed consistency regardless of screen type. For the bump rotor with a flow ratio of 5: 1 reject thickening decreases with feed consistency regardless of the screen type.
Fibre-length fractionation index <I> increased with increasing Cr to a maximum at about Ct=0.7% when using a 1-mm smooth-holed screen with a bump rotor or at Ct=2% for a 2.4-mm smooth-holed screen. Fractionation index then decreased with increasing Cf. 
It is recommended that the back-flow model be further developed so that the volumetric flow ratio (ratio of forward flow to back flow) can be calculated from a residence time distribution. It is also recommended that fibre-length fractionation be attempted at various positions along the screen for medium consistency pulp (Cr of 8 to 12%) using unconventionally large holes (3-5 mm).

year: 2006

title: Māori medical student and physician exposure to racism, discrimination, harassment, and bullying

authors: Cormack, Donna

abstract: IMPORTANCE: Discrimination, bullying, and harassment in medicine have been reported internationally, but exposures for Indigenous medical students and physicians, and for racism
specifically, remain less examined.
OBJECTIVE: To examine the prevalence of racism, discrimination, bullying, and harassment for Māori medical students and physicians in New Zealand and associations with demographic and clinical
characteristics.
DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used data from an anonymous national survey of Māori medical students and physicians in New Zealand in late 2021 and early 2022.
Data were analyzed from March 2022 to April 2024.
EXPOSURES: Age, gender, marginalized status (ie, in addition to being Māori, belonging to other groups traditionally marginalized or underrepresented in medicine), year of medical school, year of
graduation, and main work role.
MAIN OUTCOMES AND MEASURES: Direct and witnessed racism, discrimination, bullying, and harassment were measured as any experience in the last year and ever. Any exposure to negative
comments about social groups and witnessing discriminatory treatment toward Māori patients or whānau (extended family). Considering leaving medicine, including because of mistreatment, was
measured.
RESULTS: Overall, 205 Māori medical students (median [IQR] age, 23.1 [21.6-24.3] years; 137 [67.2%] women) and 200 physicians (median [IQR] age, 36.6 [30.1-45.3] years; 123 [62.8%] women)
responded. Direct and witnessed exposure to racism (184 students [91.5%]; 176 physicians [90.7%]) and discrimination (176 students [85.9%]; 179 physicians [89.5%]) ever in medical education,
training, or work environments was common. Ever exposure to witnessed and direct bullying (123 students [66.5%]; 150 physicians [89.3%]) and harassment (73 students [39.5%]; 112 physicians
[66.7%]) was also common. Most respondents reported witnessing Māori patients or their whānau being treated badly in clinical settings, in direct interactions (67 students [57.8%]; 112 physicians
[58.9%]) or behind their backs (87 students [75.0%]; 138 physicians [72.6%]). One-quarter of Māori medical students (45 students), and 37.0%of physicians (61 physicians) had considered leaving or taken a break from medicine because of these experiences. Additional marginalized statuses were significantly associated with any direct experience of mistreatment in the last year for students and physicians. Exposure to some forms of mistreatment were also significantly associated with higher likelihood of thinking about leaving or taking a break from medicine for physicians.
CONCLUSIONS AND RELEVANCE: In this study, Māori medical students and physicians reported high exposure to multiple forms of racism, discrimination, bullying, and harassment in medical
education, training, and work environments, requiring an urgent response from medical institutions.

text: Māori medical student and physician exposure to racism, discrimination, harassment, and bullying IMPORTANCE: Discrimination, bullying, and harassment in medicine have been reported internationally, but exposures for Indigenous medical students and physicians, and for racism
specifically, remain less examined.
OBJECTIVE: To examine the prevalence of racism, discrimination, bullying, and harassment for Māori medical students and physicians in New Zealand and associations with demographic and clinical
characteristics.
DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used data from an anonymous national survey of Māori medical students and physicians in New Zealand in late 2021 and early 2022.
Data were analyzed from March 2022 to April 2024.
EXPOSURES: Age, gender, marginalized status (ie, in addition to being Māori, belonging to other groups traditionally marginalized or underrepresented in medicine), year of medical school, year of
graduation, and main work role.
MAIN OUTCOMES AND MEASURES: Direct and witnessed racism, discrimination, bullying, and harassment were measured as any experience in the last year and ever. Any exposure to negative
comments about social groups and witnessing discriminatory treatment toward Māori patients or whānau (extended family). Considering leaving medicine, including because of mistreatment, was
measured.
RESULTS: Overall, 205 Māori medical students (median [IQR] age, 23.1 [21.6-24.3] years; 137 [67.2%] women) and 200 physicians (median [IQR] age, 36.6 [30.1-45.3] years; 123 [62.8%] women)
responded. Direct and witnessed exposure to racism (184 students [91.5%]; 176 physicians [90.7%]) and discrimination (176 students [85.9%]; 179 physicians [89.5%]) ever in medical education,
training, or work environments was common. Ever exposure to witnessed and direct bullying (123 students [66.5%]; 150 physicians [89.3%]) and harassment (73 students [39.5%]; 112 physicians
[66.7%]) was also common. Most respondents reported witnessing Māori patients or their whānau being treated badly in clinical settings, in direct interactions (67 students [57.8%]; 112 physicians
[58.9%]) or behind their backs (87 students [75.0%]; 138 physicians [72.6%]). One-quarter of Māori medical students (45 students), and 37.0%of physicians (61 physicians) had considered leaving or taken a break from medicine because of these experiences. Additional marginalized statuses were significantly associated with any direct experience of mistreatment in the last year for students and physicians. Exposure to some forms of mistreatment were also significantly associated with higher likelihood of thinking about leaving or taking a break from medicine for physicians.
CONCLUSIONS AND RELEVANCE: In this study, Māori medical students and physicians reported high exposure to multiple forms of racism, discrimination, bullying, and harassment in medical
education, training, and work environments, requiring an urgent response from medical institutions.

year: 0202-07-01