title: Latitudinal distribution and mitochondrial DNA (COI) variability of Stereotydeus spp. (Acari: Prostigmata) in Victoria Land and the central Transantarctic Mountains

authors: Demetras, Nicholas J.

subjects: Antarctica

abstract: We examined mitochondrial DNA (COI) variability and distribution of Stereotydeus spp. in Victoria Land and the Transantarctic Mountains, and constructed Neighbour Joining (NJ) and Maximum Likelihood (ML) phylogenetic trees using all publicly available COI sequences for the three Stereotydeus species present (S. belli, S. mollis and S. shoupi). We also included new COI sequences from Miers, Marshall and Garwood valleys in southern Victoria Land (78°S), as well as from the Darwin (79°S) and Beardmore Glacier (83°S) regions. Both NJ and ML methods produced trees which were similar in topology differing only in the placement of the single available S. belli sequence from Cape Hallett (72°S) and a S. mollis haplotype from Miers Valley. Pairwise sequence divergences among species ranged from 9.5–18.1%. NJ and ML grouped S. shoupi from the Beardmore Glacier region as sister to those from the Darwin with pairwise divergences of 8%. These individuals formed a monophyletic clade with high bootstrap support basal to S. mollis and S. belli. Based on these new data, we suggest that the distributional range of S. shoupi extends northward to Darwin Glacier and that a barrier to dispersal for Stereotydeus, and possibly other arthropods, exists immediately to the north of this area.

text: Latitudinal distribution and mitochondrial DNA (COI) variability of Stereotydeus spp. (Acari: Prostigmata) in Victoria Land and the central Transantarctic Mountains We examined mitochondrial DNA (COI) variability and distribution of Stereotydeus spp. in Victoria Land and the Transantarctic Mountains, and constructed Neighbour Joining (NJ) and Maximum Likelihood (ML) phylogenetic trees using all publicly available COI sequences for the three Stereotydeus species present (S. belli, S. mollis and S. shoupi). We also included new COI sequences from Miers, Marshall and Garwood valleys in southern Victoria Land (78°S), as well as from the Darwin (79°S) and Beardmore Glacier (83°S) regions. Both NJ and ML methods produced trees which were similar in topology differing only in the placement of the single available S. belli sequence from Cape Hallett (72°S) and a S. mollis haplotype from Miers Valley. Pairwise sequence divergences among species ranged from 9.5–18.1%. NJ and ML grouped S. shoupi from the Beardmore Glacier region as sister to those from the Darwin with pairwise divergences of 8%. These individuals formed a monophyletic clade with high bootstrap support basal to S. mollis and S. belli. Based on these new data, we suggest that the distributional range of S. shoupi extends northward to Darwin Glacier and that a barrier to dispersal for Stereotydeus, and possibly other arthropods, exists immediately to the north of this area.

year: 2010

title: Developing a motor analogy to teach children how to tackle safely in rugby union

authors: Povey, Kayla

subjects: motor learning

abstract: Implicit motor learning strategies have been shown to have benefits when learning a new skill, because they encourage users to accumulate little to no declarative knowledge about the motor task. The aim of this thesis was to investigate whether a specific implicit motor learning approach, learning by analogy, could help children perform safer rugby tackles and potentially reduce the risk of concussions.  
Chapter One is a review of current literature and discusses concussions, concussions in rugby, various implicit motor learning theories, and current research.
 Chapter Two represents the process in which focus groups were held with small groups of people who all had varying experience of rugby tackling. The focus groups were designed to supply us with knowledge, common ideas and themes, and the fundamentals of a safe rugby tackling, to then help us develop an analogy or analogies that encompassed most of what defines a safe rugby tackle. The first challenge was to identify the important fundamentals in a rugby tackle. From the focus group, the fundamentals commonly mentioned were ‘same foot same shoulder’, ‘eyes focused upward’, ‘head to the side’, ‘cheek to cheek’, and ‘strong wrap’. Animals were a common theme mentioned among all groups, highlighting the importance of the use of animals when developing analogies for children. Based on this information, we were able to come up with two analogies “tackle like a raging bull” (analogy 1) and “tackle like an angry bear hugging a pillow” (analogy 2).
Chapter Three details a pilot study that was conducted on 11-year-old rugby playing children. The pilot study was designed to test the two analogies that were developed in Chapter Two. All participants underwent two consecutive trials in a baseline control condition without receiving any instructions. Subsequently, half of the participants engaged in two trials using analogy 1, while the other group conducted two trials using analogy 2. The groups then swapped and completed the remaining analogy condition. 
The baseline control condition had the highest score across most of the tackling fundamentals, albeit not significantly different from either analogy 1 or analogy 2. Analogy 2 closely mirrored the control condition in most aspects. Notably, the 'dip' (cheek to cheek) aspect in analogy 2 scored marginally lower than the control, while 'same foot same shoulder' obtained a diminished score. However, analogy 2 exhibited superior performance in the wrapping technique, displaying similarities in other aspects as well. Conversely, the 'same foot same shoulder' fundamental received relatively low scores across all conditions.
This informs us that more research is required to obtain conclusive data, with a larger participant group, stronger analysis methods, addressing the impracticality of specific fundamentals when tackling a bag versus a human, and developing analogy 2 “tackle like an angry bear hugging a pillow” further to include the aspects it scored low on.

text: Developing a motor analogy to teach children how to tackle safely in rugby union Implicit motor learning strategies have been shown to have benefits when learning a new skill, because they encourage users to accumulate little to no declarative knowledge about the motor task. The aim of this thesis was to investigate whether a specific implicit motor learning approach, learning by analogy, could help children perform safer rugby tackles and potentially reduce the risk of concussions.  
Chapter One is a review of current literature and discusses concussions, concussions in rugby, various implicit motor learning theories, and current research.
 Chapter Two represents the process in which focus groups were held with small groups of people who all had varying experience of rugby tackling. The focus groups were designed to supply us with knowledge, common ideas and themes, and the fundamentals of a safe rugby tackling, to then help us develop an analogy or analogies that encompassed most of what defines a safe rugby tackle. The first challenge was to identify the important fundamentals in a rugby tackle. From the focus group, the fundamentals commonly mentioned were ‘same foot same shoulder’, ‘eyes focused upward’, ‘head to the side’, ‘cheek to cheek’, and ‘strong wrap’. Animals were a common theme mentioned among all groups, highlighting the importance of the use of animals when developing analogies for children. Based on this information, we were able to come up with two analogies “tackle like a raging bull” (analogy 1) and “tackle like an angry bear hugging a pillow” (analogy 2).
Chapter Three details a pilot study that was conducted on 11-year-old rugby playing children. The pilot study was designed to test the two analogies that were developed in Chapter Two. All participants underwent two consecutive trials in a baseline control condition without receiving any instructions. Subsequently, half of the participants engaged in two trials using analogy 1, while the other group conducted two trials using analogy 2. The groups then swapped and completed the remaining analogy condition. 
The baseline control condition had the highest score across most of the tackling fundamentals, albeit not significantly different from either analogy 1 or analogy 2. Analogy 2 closely mirrored the control condition in most aspects. Notably, the 'dip' (cheek to cheek) aspect in analogy 2 scored marginally lower than the control, while 'same foot same shoulder' obtained a diminished score. However, analogy 2 exhibited superior performance in the wrapping technique, displaying similarities in other aspects as well. Conversely, the 'same foot same shoulder' fundamental received relatively low scores across all conditions.
This informs us that more research is required to obtain conclusive data, with a larger participant group, stronger analysis methods, addressing the impracticality of specific fundamentals when tackling a bag versus a human, and developing analogy 2 “tackle like an angry bear hugging a pillow” further to include the aspects it scored low on.

year: 2023

title: The marine reservoir effect in the Southern Ocean: an evaluation of extant and new R values and their application to archaeological chronologies

authors: Petchey, Fiona

subjects: ∆R

abstract: The last phase of human colonisation of the south-west Pacific occurred around the 12th Century AD amongst the islands of the subtropical and temperate zones of the Southern Ocean (i.e., Norfolk Island, the Kermadec Islands, New Zealand and the Chatham Islands) (Fig. 1). Archaeological evidence indicates that initial colonisation of the region was rapid, possibly taking less than 100 years. Unfortunately, the chronology of these events has been largely reliant on charcoal radiocarbon determinations that have not been successful in delineating these changes. This paper investigates the use of marine shell for radiocarbon dating as an alternative to charcoal, with specific focus on variation in the marine 14C reservoir (specifically the ∆R) of Raoul Island (Kermadec Islands), Norfolk Island and Chatham Island (Fig. 2). Results from known-age, pre-AD 1950 shellfish indicate that ∆R values south of the South Pacific Convergence Zone are low compared to those recorded for islands within the South Pacific generally (Fig. 1) (see Petchey et al.in press). An average ∆R value of –19 ± 13 14C yr is recorded for Raoul Island and –49 ± 10 14C yr for Norfolk Island. These values are attributed to heightened absorption of atmospheric CO2 in this region. Extant published ∆R information from New Zealand (Fig. 2A) also suggests a low average ∆R value for these southern waters, but the range of values indicates that considerable variability is possible because of the complex interplay of currents around the New Zealand coastline. In contrast, results from Chatham Island are more variable and much higher (average ∆R = 134 ± 83 14C yr). Stable oxygen and carbon isotope data support the hypothesis that these ∆R values are caused by upwelling and mixing of 14C-depleted water along the Chatham Rise. Comparison of marine and charcoal 14C determinations from archaeological sites on Raoul Island support, within the limits of the available data, the ∆R values obtained, but further analysis is required to establish the stability of this value over time.

text: The marine reservoir effect in the Southern Ocean: an evaluation of extant and new R values and their application to archaeological chronologies The last phase of human colonisation of the south-west Pacific occurred around the 12th Century AD amongst the islands of the subtropical and temperate zones of the Southern Ocean (i.e., Norfolk Island, the Kermadec Islands, New Zealand and the Chatham Islands) (Fig. 1). Archaeological evidence indicates that initial colonisation of the region was rapid, possibly taking less than 100 years. Unfortunately, the chronology of these events has been largely reliant on charcoal radiocarbon determinations that have not been successful in delineating these changes. This paper investigates the use of marine shell for radiocarbon dating as an alternative to charcoal, with specific focus on variation in the marine 14C reservoir (specifically the ∆R) of Raoul Island (Kermadec Islands), Norfolk Island and Chatham Island (Fig. 2). Results from known-age, pre-AD 1950 shellfish indicate that ∆R values south of the South Pacific Convergence Zone are low compared to those recorded for islands within the South Pacific generally (Fig. 1) (see Petchey et al.in press). An average ∆R value of –19 ± 13 14C yr is recorded for Raoul Island and –49 ± 10 14C yr for Norfolk Island. These values are attributed to heightened absorption of atmospheric CO2 in this region. Extant published ∆R information from New Zealand (Fig. 2A) also suggests a low average ∆R value for these southern waters, but the range of values indicates that considerable variability is possible because of the complex interplay of currents around the New Zealand coastline. In contrast, results from Chatham Island are more variable and much higher (average ∆R = 134 ± 83 14C yr). Stable oxygen and carbon isotope data support the hypothesis that these ∆R values are caused by upwelling and mixing of 14C-depleted water along the Chatham Rise. Comparison of marine and charcoal 14C determinations from archaeological sites on Raoul Island support, within the limits of the available data, the ∆R values obtained, but further analysis is required to establish the stability of this value over time.

year: 2008