title: Abiotic factors influence microbial diversity in permanently cold soil horizons of a maritime-associated Antarctic Dry Valley

authors: Stomeo, Francesca

subjects: Active layer

abstract: The McMurdo Dry Valleys collectively comprise the most extensive ice-free region in Antarctica and are considered one of the coldest arid environments on Earth. In low-altitude maritime-associated valleys, mineral soil profiles show distinct horizontal structuring, with a surface arid zone overlying a moist and biologically active zone generated by seasonally melted permafrost. In this study, long-term microenvironmental monitoring data show that temperature and soil humidity regimes vary in the soil horizons of north- and south-facing slopes within the Miers Valley, a maritime valley in the McMurdo Dry Valleys. We found that soil bacterial communities varied from the north to the south. The microbial assemblages at the surface and shallow subsurface depths displayed higher metabolic activity and diversity compared to the permafrost soil interface. Multivariate analysis indicated that K, C, Ca and moisture influenced the distribution and structure of microbial populations. Furthermore, because of the large % RH gradient between the frozen subsurface and the soil surface we propose that water transported to the surface as water vapour is available to microbial populations, eit

text: Abiotic factors influence microbial diversity in permanently cold soil horizons of a maritime-associated Antarctic Dry Valley The McMurdo Dry Valleys collectively comprise the most extensive ice-free region in Antarctica and are considered one of the coldest arid environments on Earth. In low-altitude maritime-associated valleys, mineral soil profiles show distinct horizontal structuring, with a surface arid zone overlying a moist and biologically active zone generated by seasonally melted permafrost. In this study, long-term microenvironmental monitoring data show that temperature and soil humidity regimes vary in the soil horizons of north- and south-facing slopes within the Miers Valley, a maritime valley in the McMurdo Dry Valleys. We found that soil bacterial communities varied from the north to the south. The microbial assemblages at the surface and shallow subsurface depths displayed higher metabolic activity and diversity compared to the permafrost soil interface. Multivariate analysis indicated that K, C, Ca and moisture influenced the distribution and structure of microbial populations. Furthermore, because of the large % RH gradient between the frozen subsurface and the soil surface we propose that water transported to the surface as water vapour is available to microbial populations, eit

year: 2012

title: Investigation of a discus-milling process using a powder mixture of Al and TiO₂

authors: Liu, Z. G.

abstract: In this study, a powder mixture of Al and TiO₂ was employed to investigate the milling process in a discus mill. In this first report on this novel mechanical mill, several variables, including the milling time and powder charge and their effects on the microstructural evolution of powder particles, are monitored and studied. The study reveals that the dominant parameters of the milling process are the milling time and the starting powder charge, similar to the other high-energy ball-milling processes. The longer the milling time and the smaller the starting powder charge, the more homogeneous the mixing and the finer the microstructure of the powder particles. The reaction between Al and TiO₂ was not observed with a milling period as long as 6 hours, for the present materials. However, the reaction between Al and TiO₂, during the subsequent heat treatment, is influenced by the milling condition. The powders with the longer milling times and finer mixing microstructures also form a finer microstructure, after the reaction between Al and TiO₂  during heat treatment. The methods for achieving an optimal milling efficiency for the Al- TiO₂  system are discussed.

text: Investigation of a discus-milling process using a powder mixture of Al and TiO₂ In this study, a powder mixture of Al and TiO₂ was employed to investigate the milling process in a discus mill. In this first report on this novel mechanical mill, several variables, including the milling time and powder charge and their effects on the microstructural evolution of powder particles, are monitored and studied. The study reveals that the dominant parameters of the milling process are the milling time and the starting powder charge, similar to the other high-energy ball-milling processes. The longer the milling time and the smaller the starting powder charge, the more homogeneous the mixing and the finer the microstructure of the powder particles. The reaction between Al and TiO₂ was not observed with a milling period as long as 6 hours, for the present materials. However, the reaction between Al and TiO₂, during the subsequent heat treatment, is influenced by the milling condition. The powders with the longer milling times and finer mixing microstructures also form a finer microstructure, after the reaction between Al and TiO₂  during heat treatment. The methods for achieving an optimal milling efficiency for the Al- TiO₂  system are discussed.

year: 2006

title: He Matapihi Mā Mua, Mō Muri: The Ethics, Processes, and Procedures Associated with the Digitization of Indigenous Knowledge—The Pei Jones Collection

authors: Whaanga, Hēmi

abstract: The digital era has transformed how people live their lives and interact with the world and knowledge systems around them. In Aotearoa/New Zealand a range of initiatives incorporating Indigenous knowledge have been implemented to collect, catalog, maintain, and organize digital objects. In this article, we report on the ethics, processes, and procedures associated with the digitization of the manuscripts, works, and collected taonga (treasures) of the late Dr. Pei Te Hurinui Jones—and describe how it was transformed into a digital library. It discusses the decision-making processes and the various roles and responsibilities of the researchers, family members, and institute in this process.

text: He Matapihi Mā Mua, Mō Muri: The Ethics, Processes, and Procedures Associated with the Digitization of Indigenous Knowledge—The Pei Jones Collection The digital era has transformed how people live their lives and interact with the world and knowledge systems around them. In Aotearoa/New Zealand a range of initiatives incorporating Indigenous knowledge have been implemented to collect, catalog, maintain, and organize digital objects. In this article, we report on the ethics, processes, and procedures associated with the digitization of the manuscripts, works, and collected taonga (treasures) of the late Dr. Pei Te Hurinui Jones—and describe how it was transformed into a digital library. It discusses the decision-making processes and the various roles and responsibilities of the researchers, family members, and institute in this process.

year: 2015