title: Stochastic and deterministic effects of a moisture gradient on soil microbial communities in the McMurdo Dry Valleys of Antarctica

authors: Lee, Kevin C.

subjects: Science & Technology

abstract: Antarctic soil supports surface microbial communities that are dependent on ephemeral moisture. Understanding the response to availability of this resource is essential to predicting how the system will respond to climate change. The McMurdo Dry Valleys are the largest ice-free soil region in Antarctica. They are a hyper-arid polar desert with extremely limited moisture availability. Microbial colonization dominates this ecosystem but surprisingly little is known about how communities respond to changing moisture regimes. We utilized the natural model system provided by transiently wetted soil at lake margins in the Dry Valleys to interrogate microbial responses along a well-defined contiguous moisture gradient and disentangle responses between and within phyla. We identified a striking non-linear response among bacteria where at low moisture levels small changes resulted in a large impact on diversity. At higher moister levels community responses were less pronounced, resulting in diversity asymptotes. We postulate that whilst the main drivers of observed community diversity were deterministic, a switch in the major influence occurred from abiotic factors at low moisture levels to biotic interactions at higher moisture. Response between and within phyla was markedly different, highlighting the importance of taxonomic resolution in community analysis. Furthermore, we resolved apparent stochasticity at high taxonomic ranks as the result of deterministic interactions taking place at finer taxonomic and spatial scales. Overall the findings provide new insight on the response to moisture and this will be useful in advancing understanding of potential ecosystem responses in the threatened McMurdo Dry Valleys system.

text: Stochastic and deterministic effects of a moisture gradient on soil microbial communities in the McMurdo Dry Valleys of Antarctica Antarctic soil supports surface microbial communities that are dependent on ephemeral moisture. Understanding the response to availability of this resource is essential to predicting how the system will respond to climate change. The McMurdo Dry Valleys are the largest ice-free soil region in Antarctica. They are a hyper-arid polar desert with extremely limited moisture availability. Microbial colonization dominates this ecosystem but surprisingly little is known about how communities respond to changing moisture regimes. We utilized the natural model system provided by transiently wetted soil at lake margins in the Dry Valleys to interrogate microbial responses along a well-defined contiguous moisture gradient and disentangle responses between and within phyla. We identified a striking non-linear response among bacteria where at low moisture levels small changes resulted in a large impact on diversity. At higher moister levels community responses were less pronounced, resulting in diversity asymptotes. We postulate that whilst the main drivers of observed community diversity were deterministic, a switch in the major influence occurred from abiotic factors at low moisture levels to biotic interactions at higher moisture. Response between and within phyla was markedly different, highlighting the importance of taxonomic resolution in community analysis. Furthermore, we resolved apparent stochasticity at high taxonomic ranks as the result of deterministic interactions taking place at finer taxonomic and spatial scales. Overall the findings provide new insight on the response to moisture and this will be useful in advancing understanding of potential ecosystem responses in the threatened McMurdo Dry Valleys system.

year: 2018

title: Cult on the rise? Students' perspectives on cult issues in secondary and national high schools in Papua New Guinea

authors: Drawii, Judy Tatu

subjects: cult issues

abstract: In the last five years there has been a dramatic increase in perceived levels of
antisocial behaviour amongst students in Secondary and National High schools
in Papua New Guinea. Certain events have caught the public's attention, such
as the burning down of school buildings and reports of Satanic worship.
Despite widespread concern, there seems to be little understanding of why such
problems are occurring and no systematic studies to estimate the exact extent of
such behaviours or their underlying cause.
The main objective of this study was to collect information about the
students' perspectives on the nature and extent of these perceived problems. For
ethical reasons, and with regard to ease of access to participants within the time
frame of the study, data were collected from the first year student teachers at
Madang Teachers' College, Papua New Guinea, who had been
Secondary/National High school students only a few months previously. As this
was an exploratory investigation, and it was not known whether participants
would feel more at ease talking one-on-one with the researcher or in groups,
two methodologies were used: focus group discussions and individual
interviews. The research was conducted over a period of three weeks in June
2007, and involved a total of 21 participants (three focus groups of five, five
and six people respectively, and six individual interviewees, one of whom also
joined a group).
The main findings to emerge from these discussions were as follows.
First, the participants explained their own and other students' behaviour in terms
of exploring old and new traditions of school life. Second, although several
participants reported knowledge of supernatural practices, many of the group
activities described in the discussions were normal activities among peer cliques
that provided a sense of belonging and positive support for school achievement.
There were no major differences in the stories told by male and female
participants, and no obvious differences in the type of information provided
under different research conditions.
There was some disagreement among participants as to whether or not school
authorities should take strong action to eliminate the possibility of cult
practices.
The findings are interpreted with reference to both Western
psychological ideas about the nature of adolescence, and to local traditions,
practices, and understandings of lifespan development. In particular, the notion
of 'searching for identity' stands out in these accounts of student behaviour.
This was an exploratory study and not designed to yield results that
provide an overall picture of the situation in the Secondary/National High
schools of Papua New Guinea. Nevertheless, participants' reports did relate to
events experienced in the majority of PNG Secondary and National High
schools, and some recommendations are tentatively offered.

text: Cult on the rise? Students' perspectives on cult issues in secondary and national high schools in Papua New Guinea In the last five years there has been a dramatic increase in perceived levels of
antisocial behaviour amongst students in Secondary and National High schools
in Papua New Guinea. Certain events have caught the public's attention, such
as the burning down of school buildings and reports of Satanic worship.
Despite widespread concern, there seems to be little understanding of why such
problems are occurring and no systematic studies to estimate the exact extent of
such behaviours or their underlying cause.
The main objective of this study was to collect information about the
students' perspectives on the nature and extent of these perceived problems. For
ethical reasons, and with regard to ease of access to participants within the time
frame of the study, data were collected from the first year student teachers at
Madang Teachers' College, Papua New Guinea, who had been
Secondary/National High school students only a few months previously. As this
was an exploratory investigation, and it was not known whether participants
would feel more at ease talking one-on-one with the researcher or in groups,
two methodologies were used: focus group discussions and individual
interviews. The research was conducted over a period of three weeks in June
2007, and involved a total of 21 participants (three focus groups of five, five
and six people respectively, and six individual interviewees, one of whom also
joined a group).
The main findings to emerge from these discussions were as follows.
First, the participants explained their own and other students' behaviour in terms
of exploring old and new traditions of school life. Second, although several
participants reported knowledge of supernatural practices, many of the group
activities described in the discussions were normal activities among peer cliques
that provided a sense of belonging and positive support for school achievement.
There were no major differences in the stories told by male and female
participants, and no obvious differences in the type of information provided
under different research conditions.
There was some disagreement among participants as to whether or not school
authorities should take strong action to eliminate the possibility of cult
practices.
The findings are interpreted with reference to both Western
psychological ideas about the nature of adolescence, and to local traditions,
practices, and understandings of lifespan development. In particular, the notion
of 'searching for identity' stands out in these accounts of student behaviour.
This was an exploratory study and not designed to yield results that
provide an overall picture of the situation in the Secondary/National High
schools of Papua New Guinea. Nevertheless, participants' reports did relate to
events experienced in the majority of PNG Secondary and National High
schools, and some recommendations are tentatively offered.

year: 2008

title: Addressing the context and complexity of indigenous language revitalization

authors: May, Stephen

subjects: revitilization

abstract: This response discusses six key themes that emerge, either explicitly or implicitly, from Nancy Hornberger's exemplary analysis of the challenges facing indigenous language revitalization initiatives, particularly as they are currently expressed and implemented in three key indigenous language education contexts--Quechua in the South American Andes; Guarani in Paraguay and Maori in Aotearoa/New Zealand. These themes include, first, the importance of recognizing the wider social and political contexts within which indigenous revitalization initiatives are invariably situated. Second, it requires a related recognition of the internationalism of these initiatives. Third, any academic analysis of indigenous language revitalization requires, or at least must benefit from, an interdisciplinary approach, as exemplified by Hornberger's own analysis. Fourth, Hornberger's continua of biliteracy provides a sufficiently robust framework to explore the complexities and interrelationships inevitably involved in the articulation of language revitalization efforts, as well as how individuals and groups are situated in relation to those efforts. Fifth, the ongoing challenges and tensions inherent in indigenous language revitalization efforts need to continue to be discussed candidly, in order for them to be seriously addressed and, where possible, resolved. And finally, the importance of recognizing and including the voices of those centrally involved in these initiatives, as Hornberger again does, is a crucial feature, as well as a reflection of the inclusive, emancipatory aims of indigenous language revitalization itself.

text: Addressing the context and complexity of indigenous language revitalization This response discusses six key themes that emerge, either explicitly or implicitly, from Nancy Hornberger's exemplary analysis of the challenges facing indigenous language revitalization initiatives, particularly as they are currently expressed and implemented in three key indigenous language education contexts--Quechua in the South American Andes; Guarani in Paraguay and Maori in Aotearoa/New Zealand. These themes include, first, the importance of recognizing the wider social and political contexts within which indigenous revitalization initiatives are invariably situated. Second, it requires a related recognition of the internationalism of these initiatives. Third, any academic analysis of indigenous language revitalization requires, or at least must benefit from, an interdisciplinary approach, as exemplified by Hornberger's own analysis. Fourth, Hornberger's continua of biliteracy provides a sufficiently robust framework to explore the complexities and interrelationships inevitably involved in the articulation of language revitalization efforts, as well as how individuals and groups are situated in relation to those efforts. Fifth, the ongoing challenges and tensions inherent in indigenous language revitalization efforts need to continue to be discussed candidly, in order for them to be seriously addressed and, where possible, resolved. And finally, the importance of recognizing and including the voices of those centrally involved in these initiatives, as Hornberger again does, is a crucial feature, as well as a reflection of the inclusive, emancipatory aims of indigenous language revitalization itself.

year: 2006-01-01