title: Microbial succession under freeze–thaw events and its potential for hydrocarbon degradation in nutrient-amended Antarctic soil

authors: de Jesus, HE

subjects: Science & Technology

abstract: The polar regions have relatively low richness and diversity of plants and animals, and the basis of the entire ecological chain is supported by microbial diversity. In these regions, understanding the microbial response against environmental factors and anthropogenic disturbances is essential to understand patterns better, prevent isolated events, and apply biotechnology strategies. The Antarctic continent has been increasingly affected by anthropogenic contamination, and its constant temperature fluctuations limit the application of clean recovery strategies, such as bioremediation. We evaluated the bacterial response in oil-contaminated soil through a nutrient-amended microcosm experiment using two temperature regimes: (i) 4 C and (ii) a freeze–thaw cycle (FTC) alternating between −20 and 4 C. Bacterial taxa, such as Myxococcales, Chitinophagaceae, and Acidimicrobiales, were strongly related to the FTC. Rhodococcus was positively related to contaminated soils and further stimulated under FTC conditions. Additionally, the nutrient-amended treatment under the FTC regime enhanced bacterial groups with known biodegradation potential and was efficient in removing hydrocarbons of diesel oil. The experimental design, rates of bacterial succession, and level of hydrocarbon transformation can be considered as a baseline for further studies aimed at improving bioremediation strategies in environments affected by FTC regimes. ◦ ◦

text: Microbial succession under freeze–thaw events and its potential for hydrocarbon degradation in nutrient-amended Antarctic soil The polar regions have relatively low richness and diversity of plants and animals, and the basis of the entire ecological chain is supported by microbial diversity. In these regions, understanding the microbial response against environmental factors and anthropogenic disturbances is essential to understand patterns better, prevent isolated events, and apply biotechnology strategies. The Antarctic continent has been increasingly affected by anthropogenic contamination, and its constant temperature fluctuations limit the application of clean recovery strategies, such as bioremediation. We evaluated the bacterial response in oil-contaminated soil through a nutrient-amended microcosm experiment using two temperature regimes: (i) 4 C and (ii) a freeze–thaw cycle (FTC) alternating between −20 and 4 C. Bacterial taxa, such as Myxococcales, Chitinophagaceae, and Acidimicrobiales, were strongly related to the FTC. Rhodococcus was positively related to contaminated soils and further stimulated under FTC conditions. Additionally, the nutrient-amended treatment under the FTC regime enhanced bacterial groups with known biodegradation potential and was efficient in removing hydrocarbons of diesel oil. The experimental design, rates of bacterial succession, and level of hydrocarbon transformation can be considered as a baseline for further studies aimed at improving bioremediation strategies in environments affected by FTC regimes. ◦ ◦

year: 2021-03-01

title: The estimation and interpretation of coefficients in panel gravity models of migration

authors: Cameron, Michael Patrick

subjects: gross migration flows

abstract: In this paper, we demonstrate that the conventional ordinary least squares and fixed effects estimators of classical gravity models of migration are biased, and that the interpretation of coefficients in the fixed effects gravity model is typically incorrect. We then present a best linear unbiased (BLU) estimator for gravity models of migration, and illustrate its application with inter-regional data from New Zealand. The results demonstrate that the standard ordinary least squares and fixed effect models lead to biased coefficients on population. Alternative estimates that are BLU are provided for a data generating process with fixed origin and destination effects. The coefficients on population must be interpreted in this model as growth rate effects rather than level effects. Our findings also have significance for other types of spatial interaction modelling.

text: The estimation and interpretation of coefficients in panel gravity models of migration In this paper, we demonstrate that the conventional ordinary least squares and fixed effects estimators of classical gravity models of migration are biased, and that the interpretation of coefficients in the fixed effects gravity model is typically incorrect. We then present a best linear unbiased (BLU) estimator for gravity models of migration, and illustrate its application with inter-regional data from New Zealand. The results demonstrate that the standard ordinary least squares and fixed effect models lead to biased coefficients on population. Alternative estimates that are BLU are provided for a data generating process with fixed origin and destination effects. The coefficients on population must be interpreted in this model as growth rate effects rather than level effects. Our findings also have significance for other types of spatial interaction modelling.

year: 2019

title: In your face: wearing Moko - Maori facial marking in today's world

authors: Nikora, Linda Waimarie

subjects: Moko

abstract: The early voyagers, missionaries, settlers all reacted to the pukanohi, to the marked
faces of the Maori people during the period of first contact, and the century following
it. Their accounts are vivid, judgemental, revealing, telling us as much about them, as
it does about the people they described. Curiosity and horror are mixed with a
genuine fascination; where sternly evangelizing words failed, armed confrontation
occurred; and we now live with the results, te ao hou, a new world.
In this world, today, wahine mau kauae, tangata mau moko, pukanohi - wearers - are
speaking for themselves, about themselves, and commenting on how others view
them. Unanimously, they insist the decision to take the marking is about continuity,
affirmation, identity, and commitment. It is also about wearing those ancestors,
carrying them into the future; as their moko become a companion, a salient being with
its own life force, its own integrity and power, beyond the face.

text: In your face: wearing Moko - Maori facial marking in today's world The early voyagers, missionaries, settlers all reacted to the pukanohi, to the marked
faces of the Maori people during the period of first contact, and the century following
it. Their accounts are vivid, judgemental, revealing, telling us as much about them, as
it does about the people they described. Curiosity and horror are mixed with a
genuine fascination; where sternly evangelizing words failed, armed confrontation
occurred; and we now live with the results, te ao hou, a new world.
In this world, today, wahine mau kauae, tangata mau moko, pukanohi - wearers - are
speaking for themselves, about themselves, and commenting on how others view
them. Unanimously, they insist the decision to take the marking is about continuity,
affirmation, identity, and commitment. It is also about wearing those ancestors,
carrying them into the future; as their moko become a companion, a salient being with
its own life force, its own integrity and power, beyond the face.

year: 2003-08-01