Plant-soil interaction and soil carbon turnover across geochemical and topographic gradients in African tropical montane forests

Tropical forests play a central role in global carbon (C) cycles due to the high exchange rate of carbon between plants, soil, and the atmosphere. Nutrient availability in tropical forest systems controls these exchanges via their impact on tree growth, carbon productivity, and stocks. Research shows that local edaphic factors such as soil parent material and topography codetermine nutrient availability. However, the process knowledge of how tropical forests respond to changes in nutrients, the chemistry of the local parent material and topography, and the effect this has on C cycling between plants, soils, and the atmosphere remains unclear. This gap in knowledge obstructs the mechanistic understanding of the controls of C cycling in tropical forest systems. Furthermore, data for African tropical forests are scarce, as most research has focused mainly on Amazon and South Asia. This thesis tried to answer these questions and provided directions on where future research can focus. This thesis is based on both experimental (field and laboratory) and observational studies at different sites in the Eastern Congo Basin and along the Albertine Rift Valley System. It has three major parts: (a) nutrient uptake and distribution in the canopy of African tropical forests, (b) C stocks, Net Primary Productivity (NPP), and NPP C allocation between plant compartments, and (c) soil potential heterotrophic respiration (SPR) and soil organic carbon (SOC) turnover rate in forests developed along geochemical and topographic gradients. Specifically, the thesis focused on three contrasting geochemical regions (mafic magmatic, felsic metamorphic, and a mixture of sedimentary rock but distinct from mafic and felsic. Throughout the thesis, the three regions are referred to as “mafic”, “felsic”, and “sedimentary). Chapter 2 assessed canopy chemistry of 344 samples collected from different tree species growing on different parent materials and topographic positions. The data shows that tropical forest canopy chemistry shifts significantly when local soils and parent material geochemistry indicate fertility constraints, mainly due to low amounts of rock-derived nutrients. In contrast, topography did not affect canopy chemistry in the three investigated geochemical regions. Chapter 3 assessed the effects that soil parent material and topography as drivers of soil fertility have on forest NPP, C allocation, and biomass C stocks and how they relate to SOC stocks. Here a combination of two years monitoring of vegetation growth and soil geochemical properties measurements were used. The thesis found that soil fertility parameters reflecting the local parent material are the main drivers of NPP and C allocation patterns in tropical montane forests, resulting in significant differences in below to aboveground biomass ratio across geochemical regions. Topography did not constrain the variability in C allocation and NPP. Furthermore, SOC stocks showed no relation to C input in tropical forests. Instead, plant C input seemingly exceeded the maximum potential of these soils to stabilize C. Chapter 4 assessed potential heterotrophic soil respiration and SOC turnover via lab-based incubation experiments. Here, depth explicit SPR and Δ14C of samples originating from the three geochemical regions and topographic positions were measured under constant temperature and moisture conditions. The results revealed distinct patterns in soil respiration with soil depth and parent material geochemistry. The topographic origin of the samples was not the main determinant of the observed respiration rates and Δ14C. However, in situ soil hydrological conditions likely influence soil C turnover by inhibiting decomposition in valley subsoils. Overall, the results of this thesis demonstrate that, even in deeply weathered tropical soils, parent material has a long-lasting effect on soil geochemistry that can affect (1) nutrient availability, and uptake, (2) NPP, and C allocation, ultimately affecting differently above and belowground biomass, (3) microbial activity, the size of subsoil C stocks and the turnover rate of C in soil. Therefore, soil parent material and its control on soil chemistry need to be taken into account to predict C fluxes and to understand C cycling in African old-growth tropical forest systems

A Model-Driven and Business Approach to Autonomic Network Management

As corporate networks continue to expand, the technologies that underpin these enterprises must be capable of meeting the operational goals of the operators that own and manage them. Automation has enabled the impressive scaling of networks from the days of Strowger. The challenge now is not only to keep pace with the continuing huge expansion of capacity but at the same time to manage a huge increase in complexity – driven by the range of customer solutions and technologies. Recent advances in automation, programmable network interfaces, and model-driven networking will provide the possibility of closed-loop, self-optimizing, and self-healing networks. Collectively these support the goals of a truly automated network, commonly understood as “autonomic networking” even though this is a prospect yet to be achieved. This paper outlines the progress made towards autonomic networking and the framework and procedures developed during the UK Next Generation Converged Digital Infrastructure (NG-CDI) project. It outlines the operator-driven requirements and capabilities that have been identified, and proposes an autonomic management framework, and summarizes current art and the challenges that remain

Isolation of Temperature-sensitive Mutants in the Moss Physcomitrella patens and Mapping of their Causal Mutation by Genome Sequencing of Pooled Segregants

To use plants to achieve a sustainable future, it is critical to understand how plants grow, specifically how genes direct cell growth and cell division. One effective approach to investigate these genes is the isolation of conditional mutants. This project used the moss Physcomitrella patens as the model organism and focused on isolating temperature sensitive mutants with impaired growth, characterizing their morphology under the restrictive condition, as well as trying to identify the genetic mutation that causes the temperature-sensitive phenotype

Reactive electron scattering from biomolecules and technologically relevant molecules

The role of a set of gases relevant within the context of biomolecules and technologically relevant molecules under the interaction of low-energy electrons was studied in an effort to contribute to the understanding of the underlying processes yielding negative ion formation. The results are relevant within the context of damage to living material exposed to energetic radiation, to the role of dopants in the ion-molecule chemistry processes, to Electron Beam Induced Deposition (EBID) and Ion Beam Induced Deposition (IBID) techniques. The research described in this thesis addresses dissociative electron attachment (DEA) and electron transfer studies involving experimental setups from the University of Innsbruck, Austria and Universidade Nova de Lisboa, Portugal, respectively. This thesis presents DEA studies, obtained by a double focusing mass spectrometer, of dimethyl disulphide (C2H6S2), two isomers, enflurane and isoflurane (C3F5Cl5) and two chlorinated ethanes, pentachloroethane (C2HCl5) and hexachloroethane (C2Cl6), along with quantum chemical calculations providing information on the molecular orbitals as well as thermochemical thresholds of anion formation for enflurane, isoflurane, pentachloroethane and hexachloroethane. The experiments represent the most accurate DEA studies to these molecules, with significant differences from previous work reported in the literature. As far as electron transfer studies are concerned, negative ion formation in collisions of neutral potassium atoms with N1 and N3 methylated pyrimidine molecules were obtained by time-of-flight mass spectrometry (TOF). The results obtained allowed to propose concerted mechanisms for site and bond selective excision of bonds

Strategies for converting traditional academic library spaces to research commons : a South African perspective

Background: Over the years, the traditional academic library has been the quintessential repository for hard-copy materials and relevant information resources to support the teaching, learning and research activities of their parent universities. Accordingly, the reinvention of the academic library and its transition to the research commons model was induced by the combined effect of historical and momentous developments such as :globalisation; the worldwide democratisation of societies; the advent of mass higher education; as well as the irreversible proliferation of information and communication technologies and their tectonic impact on the knowledge economy. Purpose: This research study investigated strategies applied when converting traditional university libraries to the research commons service delivery model in South Africa. The study also sought participants’ perspectives in the identification of success factors and constraints to such conversion strategies. Methodology :The study adopted a combined qualitative-quantitative approach involving interviews, observations and questionnaires. Three public university libraries in Gauteng Province were involved as case studies to determine the extent of their orientation to the research commons model. In this regard, the study sample consisted of a manager/librarian from each of the three university libraries. Data was collected primarily by means of a survey questionnaire and semi-structured individual interviews. Explorative, descriptive and interpretive elements were applied to complement the data collection and analysis processes. Thematic data analysis was used for the ultimate categorisation and merging of both the questionnaire- and interview-based data accrued rom the selected participants. Results: Overall, the study found that careful planning and identification of positive conversion factors were critical aspects for successful implementation and evolution of any current or future research commons model. Critical factors included :formation of a research library consortium; establishing one-stop multifunctional spaces; and ongoing user and space assessment to adjust services, resources and spaces accordingly to suit changing technologies, postgraduate needs and contemporary learning styles on time and as required .Meanwhile, conversion hindrances included: model misconception by university leadership; strategic planning and change management deficiencies; poor communication; homogeneous staffing models and budgetary constraints.Information ScienceM.A. (Information Science

Bridging the gap between Open and User Innovation? : exploring the value of Living Labs as a means to structure user contribution and manage distributed innovation

In nowadays society, organizations are struggling with the practical implementation of ‘distributed innovation’, or the fact that organizations need to reach outside their boundaries to tap into distributed sources of knowledge to enhance their innovation processes. Within this PhD, we will look at a specific approach, promoted and supported by the European Commission, that tries to facilitate and manage distributed innovation processes through a Public-Private-People partnership with a central role for the end-user: Living Labs. Following Almirall & Wareham (2011) and Leminen et al. (2014), we define Living Labs as an organized approach (as opposed to an ad hoc approach) to innovation consisting of real-life experimentation and active user involvement by means of different methods involving multiple stakeholders, as is implied in the Public-Private-People character of Living Labs. However, there are two main problems associated with these Living Labs. First problem, in terms of Living Lab practice and activity, is that there seem to be too many initiatives, without enough noticeable results or impact. This is linked to the second problem, dealing with Living Labs theory. To this date, there have been a lot of Living Lab publications, but there is no consistency in terms of connection to larger research paradigms and frameworks, and there is a lack of papers with a significant academic impact as well as research clearly illustrating their value. Therefore, from a theoretical perspective, we have investigated both the Open and User Innovation paradigms and demonstrated that Living Labs are an embodiment of both, although there are only few references to these literature streams in the current Living Labs literature. From a practice perspective, we have illustrated that Living Labs are rooted within various European predecessors such as cooperative design, social experiments and ‘digital cities’, but that out of the 345 affiliated members to the European Network of Living Labs, at least 40% is currently inactive. In order to further evolve Living Labs as a concept and to allow a better conceptualization, we developed a three layered model, consisting of a macro level (the Living Lab constellation), the meso level (consisting of a Living Lab innovation project) and the micro level (consisting of the different methodological research steps). Moreover, within a multiple case study analysis of 4 Living Lab constellation, 21 Living Lab innovation projects and 107 methodological research steps, we have been able to demonstrate that the concepts gathered from the Open Innovation literature could be used to analyze the macro level, whereas the concepts from the User Innovation literature could be used on the micro level. Through co-creation, both levels merge on the meso level, resulting in useful contributions to the innovation in development. Therefore, we concluded that Living Labs are able to govern innovation networks and to structure user participation in concrete innovation projects

Mathematics Yearbook 2021

The Deakin University Mathematics Yearbook publishes student reports and articles in all areas of mathematics with an aim of promoting interest and engagement in mathematics and celebrating student achievements. The 2021 edition includes 7 coursework articles, where students have extended upon submissions in their mathematics units, as well as 4 articles based on student research projects conducted throughout 2020 and 2021