title: An illusory size–speed bias and railway crossing collisions

authors: Isler, Robert B.

abstract: Collisions between motor vehicles and trains at railway level crossings have been a high-profile issue for many years in New Zealand and other countries. Errors made in judging a train's speed could possibly be attributed to motorists being unknowingly subjected to a size-speed illusion and this could put them at considerable risk. Leibowitz (1985) maintained that a large object seems to be moving slower than a small object travelling at the same speed. Support has been provided for Leibowitz's theory from studies using simple shapes on a screen. However, the reasons behind the size-speed illusion remain unknown and there is no experimental evidence that it applies to an approaching train situation. To investigate these issues, we tested observers' relative speed estimation performance for a train and a car approaching at a range of speeds and distances, in a simulated environment. The data show that participants significantly underestimated the speed of the train, compared to the car. A size-speed illusion seems to be operating in the case of the approaching train in our simulation and may therefore be a risk factor in some railway level crossing collisions.

text: An illusory size–speed bias and railway crossing collisions Collisions between motor vehicles and trains at railway level crossings have been a high-profile issue for many years in New Zealand and other countries. Errors made in judging a train's speed could possibly be attributed to motorists being unknowingly subjected to a size-speed illusion and this could put them at considerable risk. Leibowitz (1985) maintained that a large object seems to be moving slower than a small object travelling at the same speed. Support has been provided for Leibowitz's theory from studies using simple shapes on a screen. However, the reasons behind the size-speed illusion remain unknown and there is no experimental evidence that it applies to an approaching train situation. To investigate these issues, we tested observers' relative speed estimation performance for a train and a car approaching at a range of speeds and distances, in a simulated environment. The data show that participants significantly underestimated the speed of the train, compared to the car. A size-speed illusion seems to be operating in the case of the approaching train in our simulation and may therefore be a risk factor in some railway level crossing collisions.

year: 2013

title: Social conflict in communities impacted by tourism

authors: Yang, Jingjing

subjects: China

abstract: This paper is based upon 12 months of ethnographic study while living among the Tuva and Kazakh people in Xinjiang Uyghur Autonomous Region, China. Based on observation, interviews, participation and secondary documents the paper uses Coser's theory of Social Conflict to suggest a four part model of how tourism engenders different forms of social conflict and fluctuating alliances between stakeholders in an environment where tourism has been introduced by agents external to the indigenous community. The actors are ethnic groupings and members of those groups, governmental officials at local, regional and national level, intermediaries of the tourism industry and private sector entrepreneurs drawn from the majority and minority ethnic groups. Tensions are identified as being based on beliefs, resources and power, and a sequential pattern of primacy is identified consistent with stages of the tourist area life cycle.

text: Social conflict in communities impacted by tourism This paper is based upon 12 months of ethnographic study while living among the Tuva and Kazakh people in Xinjiang Uyghur Autonomous Region, China. Based on observation, interviews, participation and secondary documents the paper uses Coser's theory of Social Conflict to suggest a four part model of how tourism engenders different forms of social conflict and fluctuating alliances between stakeholders in an environment where tourism has been introduced by agents external to the indigenous community. The actors are ethnic groupings and members of those groups, governmental officials at local, regional and national level, intermediaries of the tourism industry and private sector entrepreneurs drawn from the majority and minority ethnic groups. Tensions are identified as being based on beliefs, resources and power, and a sequential pattern of primacy is identified consistent with stages of the tourist area life cycle.

year: 2013

title: A core phyllosphere microbiome exists across distant populations of a tree species indigenous to New Zealand

authors: Noble, Anya S.

subjects: Science & Technology

abstract: The phyllosphere microbiome is increasingly recognised as an influential component of plant physiology, yet it remains unclear whether stable host-microbe associations generally exist in the phyllosphere. Leptospermum scoparium (mānuka) is a tea tree indigenous to New Zealand, and honey derived from mānuka is widely known to possess unique antimicrobial properties. However, the host physiological traits associated with these antimicrobial properties vary widely, and the specific cause of such variation has eluded scientists despite decades of research. Notably, the mānuka phyllosphere microbiome remains uncharacterised, and its potential role in mediating host physiology has not been considered. Working within the prevailing core microbiome conceptual framework, we hypothesise that the phyllosphere microbiome of mānuka exhibits specific host association patterns congruent with those of a microbial community under host selective pressure (null hypothesis: the mānuka phyllosphere microbiome is recruited stochastically from the surrounding environment). To examine our hypothesis, we characterised the phyllosphere and associated soil microbiomes of five distinct and geographically distant mānuka populations across the North Island of New Zealand. We identified a habitat-specific and relatively abundant core microbiome in the mānuka phyllosphere, which was persistent across all samples. In contrast, non-core phyllosphere microorganisms exhibited significant variation across individual host trees and populations that was strongly driven by environmental and spatial factors. Our results demonstrate the existence of a dominant and ubiquitous core microbiome in the phyllosphere of mānuka, supporting our hypothesis that phyllosphere microorganisms of mānuka exhibit specific host association and potentially mediate physiological traits of this nationally and culturally treasured indigenous plant. In addition, our results illustrate biogeographical patterns in mānuka phyllosphere microbiomes and offer insight into factors contributing to phyllosphere microbiome assembly.

text: A core phyllosphere microbiome exists across distant populations of a tree species indigenous to New Zealand The phyllosphere microbiome is increasingly recognised as an influential component of plant physiology, yet it remains unclear whether stable host-microbe associations generally exist in the phyllosphere. Leptospermum scoparium (mānuka) is a tea tree indigenous to New Zealand, and honey derived from mānuka is widely known to possess unique antimicrobial properties. However, the host physiological traits associated with these antimicrobial properties vary widely, and the specific cause of such variation has eluded scientists despite decades of research. Notably, the mānuka phyllosphere microbiome remains uncharacterised, and its potential role in mediating host physiology has not been considered. Working within the prevailing core microbiome conceptual framework, we hypothesise that the phyllosphere microbiome of mānuka exhibits specific host association patterns congruent with those of a microbial community under host selective pressure (null hypothesis: the mānuka phyllosphere microbiome is recruited stochastically from the surrounding environment). To examine our hypothesis, we characterised the phyllosphere and associated soil microbiomes of five distinct and geographically distant mānuka populations across the North Island of New Zealand. We identified a habitat-specific and relatively abundant core microbiome in the mānuka phyllosphere, which was persistent across all samples. In contrast, non-core phyllosphere microorganisms exhibited significant variation across individual host trees and populations that was strongly driven by environmental and spatial factors. Our results demonstrate the existence of a dominant and ubiquitous core microbiome in the phyllosphere of mānuka, supporting our hypothesis that phyllosphere microorganisms of mānuka exhibit specific host association and potentially mediate physiological traits of this nationally and culturally treasured indigenous plant. In addition, our results illustrate biogeographical patterns in mānuka phyllosphere microbiomes and offer insight into factors contributing to phyllosphere microbiome assembly.

year: 2020