title: Colour normalisation to reduce inter-patient and intra-patient variability in microaneurysm detection in colour retinal images

authors: Cree, Michael J.

subjects: colour normalisation

abstract: Images of the human retina vary considerably in their appearance depending on the skin pigmentation (amount of melanin) of the subject. Some form of normalisation of colour in retinal images is required for automated analysis of images if good sensitivity and specificity at detecting lesions is to be achieved in populations involving diverse races. Here we describe an approach to colour normalisation by shade-correction intra-image and histogram normalisation inter-image. The colour normalisation is assessed by its effect on the automated detection of microaneurysms in retinal images. It is shown that the Na¨ıve Bayes classifier used in microaneurysm detection benefits from the use of features measured over colour normalised images.

text: Colour normalisation to reduce inter-patient and intra-patient variability in microaneurysm detection in colour retinal images Images of the human retina vary considerably in their appearance depending on the skin pigmentation (amount of melanin) of the subject. Some form of normalisation of colour in retinal images is required for automated analysis of images if good sensitivity and specificity at detecting lesions is to be achieved in populations involving diverse races. Here we describe an approach to colour normalisation by shade-correction intra-image and histogram normalisation inter-image. The colour normalisation is assessed by its effect on the automated detection of microaneurysms in retinal images. It is shown that the Na¨ıve Bayes classifier used in microaneurysm detection benefits from the use of features measured over colour normalised images.

year: 2005

title: The detrimental effect of hindsight, culpable causation, and gender biases on jury decisions in secondary liability cases

authors: Dixon, Sophie

abstract: Recent jury trials in the United States have tested the public’s willingness to hold parents criminally responsible for their children’s actions in mass shootings. However, due to the legal requirements of negligence, assigning secondary liability in such cases may be influenced by cognitive and social biases, potentially compromising fair decision-making. This study examines how hindsight bias, culpable causation bias, and gender bias affect jury decisions in secondary liability cases. Across three experiments, we manipulated factors that could elicit these biases. Experiment 1 tested the role of hindsight bias, predicting that jurors informed of a crime’s outcome would perceive it as more foreseeable and less able to accurately determine negligence. Experiment 2 examined culpability bias, hypothesising that—due to the stigma of illegal behaviour—a drug dealer who owns a gun would be judged more harshly than a hunter who owns a gun for the same negligent behaviour. Experiment 3 investigated gender bias, predicting that mothers—especially those violating caregiving and feminine norms—would be judged more harshly than fathers for the same negligent actions. Results revealed that hindsight bias influenced probability estimates as predicted but did not affect perceptions of negligence and culpability (Experiment 1). Consistent with predictions, however, participants assigned harsher punishments to defendants in stigmatised professions and to mothers who engaged in socially disapproved behaviours. These findings highlight the potential for bias in jury decision-making and underscore the need for legal safeguards to ensure more equitable outcomes in secondary liability cases.

text: The detrimental effect of hindsight, culpable causation, and gender biases on jury decisions in secondary liability cases Recent jury trials in the United States have tested the public’s willingness to hold parents criminally responsible for their children’s actions in mass shootings. However, due to the legal requirements of negligence, assigning secondary liability in such cases may be influenced by cognitive and social biases, potentially compromising fair decision-making. This study examines how hindsight bias, culpable causation bias, and gender bias affect jury decisions in secondary liability cases. Across three experiments, we manipulated factors that could elicit these biases. Experiment 1 tested the role of hindsight bias, predicting that jurors informed of a crime’s outcome would perceive it as more foreseeable and less able to accurately determine negligence. Experiment 2 examined culpability bias, hypothesising that—due to the stigma of illegal behaviour—a drug dealer who owns a gun would be judged more harshly than a hunter who owns a gun for the same negligent behaviour. Experiment 3 investigated gender bias, predicting that mothers—especially those violating caregiving and feminine norms—would be judged more harshly than fathers for the same negligent actions. Results revealed that hindsight bias influenced probability estimates as predicted but did not affect perceptions of negligence and culpability (Experiment 1). Consistent with predictions, however, participants assigned harsher punishments to defendants in stigmatised professions and to mothers who engaged in socially disapproved behaviours. These findings highlight the potential for bias in jury decision-making and underscore the need for legal safeguards to ensure more equitable outcomes in secondary liability cases.

year: 2025

title: Boat electrofishing survey of fish abundance in the Ohau Channel, Rotorua, in 2015

authors: Hicks, Brendan J.

abstract: The aim of the survey was to provide on-going monitoring of the fish communities and abundance by boat electrofishing in the Ohau Channel, especially fish species that are taonga to Maori (eels, goldfish, and koura). In the current study, we present the findings from the ninth year of sampling (2015) and a summary of previous surveys.
We used the University of Waikato's 4.5 m-long, aluminium-hulled electrofishing boat to catch a total of total of 1,198 fish and koura (18.9 kg) at 13 sites on 2 December 2015, which comprised 2,671 lineal m and 10,684 m² in area. Koura (freshwater crayfish) and 6 fish species were present, with common bully the most abundant species (up to 45.5 fish 100 m⁻² at the site 6, edge habitat). Goldfish (up to 4.85 100 m⁻²) was the next most abundant species, with most goldfish at sites 7 and 12-13 in and around the side channel. Rainbow trout densities were up to 0.28 fish 100 m⁻². Mean bully density (11.41 fish 100 m⁻²) was much higher than for smelt (0.29 fish 100 m⁻²). Koura had a patchy distribution; only 3 individuals were caught at one site.
Comparing catches over the 9 years of sampling, the mean abundance of common bullies in 2015 was consistent with densities in most post-wall years (after 2007), but lower than in 2007 before wall closure (ANOVA P = 0.001). The cause of fluctuating bully abundance is not known, and was not accounted for by changes in water clarity expressed as black disc distance (BDD), water temperature, or water conductivity. Poor water clarity can reduce the efficiency of electrofishing, but high BDD did not correspond with high common bully densities. In 2015, smelt abundance had recovered somewhat from the low catch in 2014.
Goldfish biomass increased initially (2009-2010) because of targeted fishing in the excavated side branch (site 11), which has dense macrophytes and offers good habitat for goldfish. The continued rise in density from 2012 on, however, suggests a real increase in goldfish numbers. In 2012 and 2013 shortfin eels were caught, but no eels were caught in 2014 and only a single longfin eel was caught in 2015.
Analysis of fish densities before and after wall closure is hampered by the single data point before closure. However, we now have 9 years of post-wall data, and comparison of means suggest that the number of bullies has been lower since 2007. An obvious cause could be interruption of bully migration into the Ohau Channel from Lake Rotoiti by the wall. This suggests that the bully population in the Ohau Channel before wall construction and closure was a mixture of fish from lakes Rotorua and Rotoiti, and that recruitment from Rotoiti is now restricted. This hypothesis is testable with otolith microchemistry.

text: Boat electrofishing survey of fish abundance in the Ohau Channel, Rotorua, in 2015 The aim of the survey was to provide on-going monitoring of the fish communities and abundance by boat electrofishing in the Ohau Channel, especially fish species that are taonga to Maori (eels, goldfish, and koura). In the current study, we present the findings from the ninth year of sampling (2015) and a summary of previous surveys.
We used the University of Waikato's 4.5 m-long, aluminium-hulled electrofishing boat to catch a total of total of 1,198 fish and koura (18.9 kg) at 13 sites on 2 December 2015, which comprised 2,671 lineal m and 10,684 m² in area. Koura (freshwater crayfish) and 6 fish species were present, with common bully the most abundant species (up to 45.5 fish 100 m⁻² at the site 6, edge habitat). Goldfish (up to 4.85 100 m⁻²) was the next most abundant species, with most goldfish at sites 7 and 12-13 in and around the side channel. Rainbow trout densities were up to 0.28 fish 100 m⁻². Mean bully density (11.41 fish 100 m⁻²) was much higher than for smelt (0.29 fish 100 m⁻²). Koura had a patchy distribution; only 3 individuals were caught at one site.
Comparing catches over the 9 years of sampling, the mean abundance of common bullies in 2015 was consistent with densities in most post-wall years (after 2007), but lower than in 2007 before wall closure (ANOVA P = 0.001). The cause of fluctuating bully abundance is not known, and was not accounted for by changes in water clarity expressed as black disc distance (BDD), water temperature, or water conductivity. Poor water clarity can reduce the efficiency of electrofishing, but high BDD did not correspond with high common bully densities. In 2015, smelt abundance had recovered somewhat from the low catch in 2014.
Goldfish biomass increased initially (2009-2010) because of targeted fishing in the excavated side branch (site 11), which has dense macrophytes and offers good habitat for goldfish. The continued rise in density from 2012 on, however, suggests a real increase in goldfish numbers. In 2012 and 2013 shortfin eels were caught, but no eels were caught in 2014 and only a single longfin eel was caught in 2015.
Analysis of fish densities before and after wall closure is hampered by the single data point before closure. However, we now have 9 years of post-wall data, and comparison of means suggest that the number of bullies has been lower since 2007. An obvious cause could be interruption of bully migration into the Ohau Channel from Lake Rotoiti by the wall. This suggests that the bully population in the Ohau Channel before wall construction and closure was a mixture of fish from lakes Rotorua and Rotoiti, and that recruitment from Rotoiti is now restricted. This hypothesis is testable with otolith microchemistry.

year: 2016