title: A comparative study of the effects of a concept mapping enhanced laboratory experience on Turkish high school students’ understanding of acid-base chemistry

authors: Özmen, Haluk

subjects: acids and bases

abstract: The research reported here consists of the introduction of an intervention based on a series of laboratory activities combined with concept mapping. The purpose of this intervention was to enhance student understanding of acid-base chemistry for tenth grade students’ from two classes in a Turkish high school. An additional aim was to enhance student attitude toward chemistry. In the research design, two cohorts of students were compared; those from the intervention group (N = 31) and a second group (N = 28) who were taught in a more traditional manner. Student understanding of acid-base chemistry was evaluated with a pretest/posttest research design using a purpose-designed instrument, the Concept Achievement Test (CAT) consisting of 25 items, 15 multiple choice and ten multiple choice with explanation. Alternative conceptions identified in the pretest were incorporated into the intervention, which thereby sought to move students toward views more in accord with scientific views for the concepts. Statistical tests indicate the instrument is reliable (with an alpha reliability of 0.81) and the analysis of the findings revealed statistically significant differences between the intervention and traditional groups with respect to conceptual understanding. Examination of student explanations and analyses of semi-structured interviews conducted with selected students suggest that the main influence was the laboratory activities. Analysis of the findings in the context of relevant literature that concept mapping in conjunction with laboratory activities is more enjoyable, helps student link concepts, and reduces their alternative conceptions.

text: A comparative study of the effects of a concept mapping enhanced laboratory experience on Turkish high school students’ understanding of acid-base chemistry The research reported here consists of the introduction of an intervention based on a series of laboratory activities combined with concept mapping. The purpose of this intervention was to enhance student understanding of acid-base chemistry for tenth grade students’ from two classes in a Turkish high school. An additional aim was to enhance student attitude toward chemistry. In the research design, two cohorts of students were compared; those from the intervention group (N = 31) and a second group (N = 28) who were taught in a more traditional manner. Student understanding of acid-base chemistry was evaluated with a pretest/posttest research design using a purpose-designed instrument, the Concept Achievement Test (CAT) consisting of 25 items, 15 multiple choice and ten multiple choice with explanation. Alternative conceptions identified in the pretest were incorporated into the intervention, which thereby sought to move students toward views more in accord with scientific views for the concepts. Statistical tests indicate the instrument is reliable (with an alpha reliability of 0.81) and the analysis of the findings revealed statistically significant differences between the intervention and traditional groups with respect to conceptual understanding. Examination of student explanations and analyses of semi-structured interviews conducted with selected students suggest that the main influence was the laboratory activities. Analysis of the findings in the context of relevant literature that concept mapping in conjunction with laboratory activities is more enjoyable, helps student link concepts, and reduces their alternative conceptions.

year: 2009

title: Structure, light & temperature induced changes in the compound eyes of Antarctic crustaceans

authors: Tiang, Kin Ming

abstract: The structure of the photoreceptors of three different Antarctic crustaceans was investigated by light and electron microscopy. Special attention was paid to light and temperature induced changes of the normal, i.e. dark-adapted eye. 
The apposition eye of Orchomene plebs shows structural modifications which are interpreted as adaptations to maximise photon capture in an environment of low ambient light intensities. Dark-light adaptational changes affect the position of the screening pigment granules, the volume of the random and the composition and density of the organelles in both retinula and interstitial cells. Exposure to a temperature of +10°c for seven hours affects the structural integrity of the rhabdoms and mimicks light-adaptation in animals that are kept in the dark. Rhabdoms regenerate as long as the animals are returned to water of 0°C.
The ommatidia of the dorsal eye of Glyptonotus antarcticus possess very large diameters and are of the apposition type. Dark-light adaptational changes, which are confined to the dark eye if one eye is painted black and the other is left untouched, involve radial migration of screening pigment granules in the retinula cells surrounding the rhabdom. An elevation of the temperature also affects the position of the screening pigments, but the rhabdom ultrastructure is far less affected than that of Orchomene plebs. 
The compound eyes of the Ross Ice Shelf amphipod Orchomene grandis show the highest degree of structural adaptation to a dimly-lit environment. Following exposure to sunlight or darkness for one week at a temperature of approximately +1°C. the extraordinarily massive rhabdoms exhibit almost total disintegration. The density of screening pigment granules is so low that migrations upon dark-light adaptation are insignificant. The eye of Orchornene grandis shows the smallest capacity of all three species studied to adapt to different ambient light levels.

text: Structure, light & temperature induced changes in the compound eyes of Antarctic crustaceans The structure of the photoreceptors of three different Antarctic crustaceans was investigated by light and electron microscopy. Special attention was paid to light and temperature induced changes of the normal, i.e. dark-adapted eye. 
The apposition eye of Orchomene plebs shows structural modifications which are interpreted as adaptations to maximise photon capture in an environment of low ambient light intensities. Dark-light adaptational changes affect the position of the screening pigment granules, the volume of the random and the composition and density of the organelles in both retinula and interstitial cells. Exposure to a temperature of +10°c for seven hours affects the structural integrity of the rhabdoms and mimicks light-adaptation in animals that are kept in the dark. Rhabdoms regenerate as long as the animals are returned to water of 0°C.
The ommatidia of the dorsal eye of Glyptonotus antarcticus possess very large diameters and are of the apposition type. Dark-light adaptational changes, which are confined to the dark eye if one eye is painted black and the other is left untouched, involve radial migration of screening pigment granules in the retinula cells surrounding the rhabdom. An elevation of the temperature also affects the position of the screening pigments, but the rhabdom ultrastructure is far less affected than that of Orchomene plebs. 
The compound eyes of the Ross Ice Shelf amphipod Orchomene grandis show the highest degree of structural adaptation to a dimly-lit environment. Following exposure to sunlight or darkness for one week at a temperature of approximately +1°C. the extraordinarily massive rhabdoms exhibit almost total disintegration. The density of screening pigment granules is so low that migrations upon dark-light adaptation are insignificant. The eye of Orchornene grandis shows the smallest capacity of all three species studied to adapt to different ambient light levels.

year: 1980

title: Stigmatising gang narratives, housing, and the social policing of Māori women

authors: Lewis, Cassandra Louise Terauhina

subjects: Gang narratives

abstract: It is well established that negative stigmas are used to dehumanise and to limit, restrict, and deny assistance to poor and racially marginalised populations, especially single mothers. While scholars have examined racial social control with regard to gangs, how the stigma of gang affiliation influences access to quality housing has been scantly examined in New Zealand. Employing discourse analysis to examine parliamentary speeches regarding the Organised Crime Bill and Residential Tenancy Amendment Bill (2009–2018), this project explores how gangs are framed in housing-related political discourse. Findings reveal that language used by policymakers constructs gangs as being associated largely with Māori through three main tactics: referencing ‘ethnic’ gangs as the only entity/focus of organised crime; omitting Pākehā/White gangs and white-collar crime; and identifying areas/towns with high Māori populations as in need of targeted social control. Such framing strategies fashioned a criminalising narrative around Māori as gang members and as inherently violent that permeates housing-related political rhetoric used to frame ‘bad’ or ‘undesirable’ tenants enabling policymakers to stigmatise Māori as the ‘criminal other’. This motif carries severe implications with regard to life chances of Māori women, especially as it relates to housing screening practices and the ability to secure social housing.

text: Stigmatising gang narratives, housing, and the social policing of Māori women It is well established that negative stigmas are used to dehumanise and to limit, restrict, and deny assistance to poor and racially marginalised populations, especially single mothers. While scholars have examined racial social control with regard to gangs, how the stigma of gang affiliation influences access to quality housing has been scantly examined in New Zealand. Employing discourse analysis to examine parliamentary speeches regarding the Organised Crime Bill and Residential Tenancy Amendment Bill (2009–2018), this project explores how gangs are framed in housing-related political discourse. Findings reveal that language used by policymakers constructs gangs as being associated largely with Māori through three main tactics: referencing ‘ethnic’ gangs as the only entity/focus of organised crime; omitting Pākehā/White gangs and white-collar crime; and identifying areas/towns with high Māori populations as in need of targeted social control. Such framing strategies fashioned a criminalising narrative around Māori as gang members and as inherently violent that permeates housing-related political rhetoric used to frame ‘bad’ or ‘undesirable’ tenants enabling policymakers to stigmatise Māori as the ‘criminal other’. This motif carries severe implications with regard to life chances of Māori women, especially as it relates to housing screening practices and the ability to secure social housing.

year: 2020