title: High levels of intraspecific genetic divergences revealed for Antarctic springtails: evidence for small-scale isolation during Pleistocene glaciation

authors: Bennett, Kristi R.

subjects: Collembola

abstract: We examined levels of genetic variability within and among populations of three Antarctic springtail species (Arthropoda: Collembola) and tested the hypothesis that genetic divergences occur among glacially-isolated habitats. The study was conducted in southern Victoria Land, Ross Dependency, Antarctica, and samples were collected from locations in the vicinity of the Mackay Glacier. We analyzed mtDNA (cytochrome c oxidase subunit I; COI) sequence variability for 97 individuals representing three species (Gomphiocephalus hodgsoni, N = 67; Cryptopygus nivicolus, N = 20; and Antarcticinella monoculata, N = 8). Haplotype diversity and genetic divergences were calculated and used to indicate population variability and also to infer divergence times of isolated populations using molecular clock estimates. Two of the three species showed high levels of genetic divergence. Gomphiocephalus hodgsoni, a widespread and common species, showed 7.6% sequence divergence on opposite sides of the Mackay Glacier. The more range restricted C. nivicolus showed 4.0% divergence among populations. The third species, A. monoculata, was found in only one location. Molecular clock estimates based on sequence divergences suggest that populations separated within the last 4 Mya. We conclude that habitat fragmentation resulting from Pliocene (5 Mya) and Pleistocene (2 Mya to 10 Kya) glaciations has promoted and maintained high levels of diversity among isolated springtail populations on relatively small spatial scales. The region surrounding the Mackay Glacier is likely to have provided refugia for springtail populations during glacial maxima and remains an area of high genetic and species diversity for Collembola within the Ross Sea region.

text: High levels of intraspecific genetic divergences revealed for Antarctic springtails: evidence for small-scale isolation during Pleistocene glaciation We examined levels of genetic variability within and among populations of three Antarctic springtail species (Arthropoda: Collembola) and tested the hypothesis that genetic divergences occur among glacially-isolated habitats. The study was conducted in southern Victoria Land, Ross Dependency, Antarctica, and samples were collected from locations in the vicinity of the Mackay Glacier. We analyzed mtDNA (cytochrome c oxidase subunit I; COI) sequence variability for 97 individuals representing three species (Gomphiocephalus hodgsoni, N = 67; Cryptopygus nivicolus, N = 20; and Antarcticinella monoculata, N = 8). Haplotype diversity and genetic divergences were calculated and used to indicate population variability and also to infer divergence times of isolated populations using molecular clock estimates. Two of the three species showed high levels of genetic divergence. Gomphiocephalus hodgsoni, a widespread and common species, showed 7.6% sequence divergence on opposite sides of the Mackay Glacier. The more range restricted C. nivicolus showed 4.0% divergence among populations. The third species, A. monoculata, was found in only one location. Molecular clock estimates based on sequence divergences suggest that populations separated within the last 4 Mya. We conclude that habitat fragmentation resulting from Pliocene (5 Mya) and Pleistocene (2 Mya to 10 Kya) glaciations has promoted and maintained high levels of diversity among isolated springtail populations on relatively small spatial scales. The region surrounding the Mackay Glacier is likely to have provided refugia for springtail populations during glacial maxima and remains an area of high genetic and species diversity for Collembola within the Ross Sea region.

year: 2016

title: Updated reliability and normative values for the standing heel-rise test in healthy adults

authors: Hébert-Losier, Kim

subjects: Lower extremity

abstract: Objectives

The heel-rise test is used to assess the strength and endurance of the plantar flexors in everyday clinical practice. However, several factors may affect outcomes, including sex, age, body mass index and activity level. The aims of this study were to revisit the reliability and normative values of this test, and establish normative equations accounting for several factors.

Design

Cross-sectional observational study with test–retest.

Setting

Community.

Participants

Volunteers (n = 566, age 20 to 81 years).

Interventions

Subjects performed single-legged heel rises to fatigue, standing on a 10° incline, once on each leg. A subset of subjects (n = 32) repeated the test 1 week later. Reliability was quantified using intraclass (ICC) correlation coefficients and Bland–Altman plots {mean difference [95% limits of agreement (LOA)]}, whereas the impact of sex, age, body mass index and activity level on the number of heel rises was determined using non-parametric regression models.

Results

The test showed excellent reliability (ICC = 1.0 right leg, 1.0 left leg), with mean between-day differences in the total number of heel-rise repetitions of 0.2 (95% LOA −6.2 to 6.5) and 0.1 (95% LOA −6.1 to 6.2) for right and left legs, respectively. Overall, males completed more repetitions than females (median 24 vs 21). However, older females (age >60 years) outperformed older males. According to the model, younger males with higher activity levels can complete the most heel rises.

Conclusions

The heel-rise test is highly reliable. The regression models herein can be employed by clinicians to evaluate the outcomes of heel-rise tests of individuals against a comparable normative population.

text: Updated reliability and normative values for the standing heel-rise test in healthy adults Objectives

The heel-rise test is used to assess the strength and endurance of the plantar flexors in everyday clinical practice. However, several factors may affect outcomes, including sex, age, body mass index and activity level. The aims of this study were to revisit the reliability and normative values of this test, and establish normative equations accounting for several factors.

Design

Cross-sectional observational study with test–retest.

Setting

Community.

Participants

Volunteers (n = 566, age 20 to 81 years).

Interventions

Subjects performed single-legged heel rises to fatigue, standing on a 10° incline, once on each leg. A subset of subjects (n = 32) repeated the test 1 week later. Reliability was quantified using intraclass (ICC) correlation coefficients and Bland–Altman plots {mean difference [95% limits of agreement (LOA)]}, whereas the impact of sex, age, body mass index and activity level on the number of heel rises was determined using non-parametric regression models.

Results

The test showed excellent reliability (ICC = 1.0 right leg, 1.0 left leg), with mean between-day differences in the total number of heel-rise repetitions of 0.2 (95% LOA −6.2 to 6.5) and 0.1 (95% LOA −6.1 to 6.2) for right and left legs, respectively. Overall, males completed more repetitions than females (median 24 vs 21). However, older females (age >60 years) outperformed older males. According to the model, younger males with higher activity levels can complete the most heel rises.

Conclusions

The heel-rise test is highly reliable. The regression models herein can be employed by clinicians to evaluate the outcomes of heel-rise tests of individuals against a comparable normative population.

year: 2017

title: A cultural encounter through volunteer tourism: Towards the ideals of sustainable tourism?

authors: McIntosh, Alison J.

subjects: cultural tourism

abstract: International volunteering is increasingly recognised as a form of alternative tourism. However, the nature of the ‘alternative’ experience gained, and the ensuing narrative between host and volunteer, remains under-explored in published research, especially in volunteer tourism research within a cultural context in a developed nation. This paper examines the nexus between volunteer tourism and cultural tourism in the search for alternative and sustainable experiences through tourism. Qualitative research using in-depth interviews, diaries and participant observation was conducted to examine the pre-, during and post-trip experiences of 12 Australian visitors undertaking organised volunteer activities in an indigenous Maori community in the North Island of New Zealand during January 2005. Members of the indigenous Maori community were also interviewed to provide an important host perspective. Findings suggest that the nature of the interaction and cultural experiences gained were perceived as mutually beneficial and seemingly different from those gained from traditional cultural products. In particular, the volunteers experienced an alternative Maori cultural product and engaged in a different narrative with their Maori hosts through their volunteer work, one rich in authentic cultural content, genuine and reflective of modern Maori life in New Zealand society.

text: A cultural encounter through volunteer tourism: Towards the ideals of sustainable tourism? International volunteering is increasingly recognised as a form of alternative tourism. However, the nature of the ‘alternative’ experience gained, and the ensuing narrative between host and volunteer, remains under-explored in published research, especially in volunteer tourism research within a cultural context in a developed nation. This paper examines the nexus between volunteer tourism and cultural tourism in the search for alternative and sustainable experiences through tourism. Qualitative research using in-depth interviews, diaries and participant observation was conducted to examine the pre-, during and post-trip experiences of 12 Australian visitors undertaking organised volunteer activities in an indigenous Maori community in the North Island of New Zealand during January 2005. Members of the indigenous Maori community were also interviewed to provide an important host perspective. Findings suggest that the nature of the interaction and cultural experiences gained were perceived as mutually beneficial and seemingly different from those gained from traditional cultural products. In particular, the volunteers experienced an alternative Maori cultural product and engaged in a different narrative with their Maori hosts through their volunteer work, one rich in authentic cultural content, genuine and reflective of modern Maori life in New Zealand society.

year: 2007