Using high resolution optical imagery to detect earthquake-induced liquefaction: the 2011 Christchurch earthquake

Using automated supervised methods with satellite and aerial imageries for liquefaction mapping is a promising step in providing detailed and region-scale maps of liquefaction extent immediately after an earthquake. The accuracy of these methods depends on the quantity and quality of training samples and the number of available spectral bands. Digitizing a large number of high-quality training samples from an event may not be feasible in the desired timeframe for rapid response as the training pixels for each class should be typical and accurately represent the spectral diversity of that specific class. To perform automated classification for liquefaction detection, we need to understand how to build the optimal and accurate training dataset. Using multispectral optical imagery from the 22 February, 2011 Christchurch earthquake, we investigate the effects of quantity of high-quality training pixel samples as well as the number of spectral bands on the performance of a pixel-based parametric supervised maximum likelihood classifier for liquefaction detection. We find that the liquefaction surface effects are bimodal in terms of spectral signature and therefore, should be classified as either wet liquefaction or dry liquefaction. This is due to the difference in water content between these two modes. Using 5-fold cross-validation method, we evaluate performance of the classifier on datasets with different pixel sizes of 50, 100, 500, 2000, and 4000. Also, the effect of adding spectral information was investigated by adding once only the near infrared (NIR) band to the visible red, green, and blue (RGB) bands and the other time using all available 8 spectral bands of the World-View 2 satellite imagery. We find that the classifier has high accuracies (75%–95%) when using the 2000 pixels-size dataset that includes the RGB+NIR spectral bands and therefore, increasing to 4000 pixels-size dataset and/or eight spectral bands may not be worth the required time and cost. We also investigate accuracies of the classifier when using aerial imagery with same number of training pixels and either RGB or RGB+NIR bands and find that the classifier accuracies are higher when using satellite imagery with same number of training pixels and spectral information. The classifier identifies dry liquefaction with higher user accuracy than wet liquefaction across all evaluated scenarios. To improve classification performance for wet liquefaction detection, we also investigate adding geospatial information of building footprints to improve classification performance. We find that using a building footprint mask to remove them from the classification process, increases wet liquefaction user accuracy by roughly 10%.Published versio

Soil creep: a process study in Killhope basin, upper Weardale, northern Pennines, England

The object of this research is to investigate the rate of soil creep and. its controlling variables at Killhope basin in Upper Weardale (Northern Pennines). The experimental work was designed to trace the movement of soil. Five sites were selected for study (three on peaty soils and two on mineral soils). At each site a set of four different instruments (an Anderson's tube, a Young's pit, wooden pillars and Rashidian's instrument)were used to measure creep rates for 18 months. To investigate which variables control this process, soil samples from sampling sites were used for quantitative analysis. The results of this study indicate: 1. Annual linear rates of soil creep varied from 0.58 mm to 1.52 mm.2. A strong relationship between creep rate and soil moisture content and its fluctuations.3. Higher creep rates for organic soils than for mineral soils.4. Non-exponential decline of rate of movement with depth.5. No evidence for the influence of slope angle on creep rate.6. The small differences in values recorded by different instruments show that the Rashidian technique was sufficiently accurate and useful for monitoring seasonal soil creep

The role of primary eye health care in controlling the surge of monkeypox

Letter to the edito

Deflector effects in fixed bed (biomass) combustors and non-combusting packed beds

Combustion can be used to thermally process biomass fuels and yield both heat and power in a sustainable manner. At present, direct combustion of solid biomass is the primary approach for generating electricity and heat when these fuels are used at a commercial scale. Deflectors have been used in the freeboard section of industrial combustors to reduce radiant heat loss through flue gases and for particle emissions abatement. Freeboard deflectors can also influence emissions and freeboard temperature distributions by changing the flow dynamics. Despite much research into laboratory scale biomass combustion and packed beds, there have been no systematic studies into the impact of deflectors (heat shields) on the axial and radial temperature profiles, test methodologies used or the emissions in laboratory scale fixed bed biomass combustors operated on pelletised fuels. Through a combination of experiments and numerical simulations, this research has investigated such issues in both high temperature fixed bed biomass combustors as well as relatively lower temperature (non-combusting) packed beds subject to different heating modes. Experiments have been carried out on a laboratory scale (continuous feed) fixed bed combustor featuring both primary air (supplied through the fuel bed) as well as secondary air (in the freeboard). A freeboard deflector was located at different axial locations during this testing. The aim was to characterize deflector effects on burning rate, temperature distribution (near-wall and near-centreline) and gaseous emissions (NO, CO, CO2) over a range of primary and secondary air flow rates. A systematic method has been developed to establish the steady state time period during the combustion process. In this regard, detailed analyses on the time series of thermocouples, emissions and fuel mass conversion data have been performed. The proposed method is based on calculating the percentile mean deviation of temperature and NO/CO emissions data which can provide a more effective means of resolving the stand of the steady state operating, compared to only using the time evolution of these variables. In addition, the significance of the thermocouple radiative corrections (losses) and its effect on the accuracy of measured temperatures has been investigated. The results concluded that NO, CO and CO2 emissions are affected by the presence of a deflector in the mid-range of combustion stoichiometry (λ=0.439-0.509). However, deflector effects were found to be most prominent for NO and CO emissions by reducing and rising their levels, respectively. Deflectors affect upstream near-wall temperatures, but their impact depends on relative (axial) position (H). Furthermore, results reveal that deflectors do not have significant effects on the burning rate and flow availability of the exhaust gases. A CFD model of a porous media has been implanted to study the effects of freeboard deflectors on the heat transfer inside packed bed columns for the temperature range of 100°C to 400°C (which is typical for drying and volatile release in biomass combustion). Results show that the deflector do affect temperature profiles along the freeboard as well as wall temperatures but this is dependent on the mode of heating and emissivity of the deflector

Roles, responsibilities, and job description of ophthalmic nurses, a universal definition is required

Letter to the Edito

Immunological interactions of virus peptides at the antigen presenting MHC I proteins

Regarding the recent outbreak of Zika virus (ZIKV) infection, there is an urgent need to develop a preventive or a therapeutic ZIKV vaccine. In this thesis, computational analysis was performed to predict suitable peptide candidates for vaccine design. Computational approaches such as docking and molecular dynamics simulations (MD simulations) were employed to evaluate the binding energy and stability of candidate T-cell epitope peptides of ZIKV proteins at the antigen-presenting MHC class I molecules. For the docking step and the following MD simulations, MHC I alleles HLA-A*0101, HLA-A*0201, HLA-B*2705 and HLA-C*0801 were used as receptor structures and eight different peptides from ZIKV proteins (E, NS3, NS5) were docked to the MHC I molecules. All predicted peptide-HLA complexes and experimental reference peptide-HLA complexes were submitted to a 10-ns MD simulation in explicit water for further refinement and to examine and compare their stability. Hydrogen bonding network, Root-Mean-Square Deviation (RMSD) for both the MHC I peptide-binding domain and the peptides, atomic fluctuation and solvent accessibility of the bound peptides, interaction energies and the dimensions of the peptide binding groove were analyzed to evaluate the stability and strength of the peptide-HLA complexes. The computational analysis provided two T-cell epitopes from the ZIKV proteins (GLDFSDLYY, FSDLYYLTM) with a high affinity to the studied MHC I alleles. These could be introduced as putative candidates for vaccine development

Pilot Study: Effectiveness of System Dynamics based Interactive Learning Environment SD/ILE as an interdisciplinary educational tool in K-12 classrooms

Systems thinking is a methodology used to explore and understand the interrelationships within complex systems. One of the key concepts in systems thinking are the feedback loops. This research aims to assess the effectiveness of an SD/ILE (System Dynamics-based Interactive Learning Environment) as an interdisciplinary educational tool for K-12 students, to help them develop systems thinking skills and build lateral understanding on feedback loop processes. While the concept of feedback loops is far-reaching and present in many disciplines as well as day-to-day life, this ILE references the carbon cycle as a complex system. In this study we chose to develop a lesson about “Carbon Cycle” for two reasons: first, it is part of the US high-school biology curriculum, and second, due to the current environmental crisis, it is important to learn about climate feedbacks and to provide a real-world context. This is an empirical research project based on observation of students’ learning outcomes in a pilot session. During this session, students were provided with guidelines, the online links to the ILEs and challenges to complete both individually and in teams under their teacher’s supervision. The session took place in a US high-school biology class. The obtained results through the pilot test and analyzed data, show promising increase in students’ learning curve after playing the Carbon Cycle games in comparison with the pre-test results. Evaluation of students’ understanding, and page time tracking data reveals that learning curve has a high correlation with the average time that each student spent playing the game. Moreover, the data supports the positive impact of animation-based design in the students’ learning curve along the game. Also, this pilot session provides a useful overview of challenges for real-world experiment setup and limitations of available systems thinking skills measurement tools in real-world classroom experiments. The challenges are related to different aspects of the experience, such as the teachers’ role, interactive and engaging level of the ILE (game) design, appropriate timing for playing the game, easy instruction, and suitable assessment tool for measuring individual knowledge development. Among the strongest lesson learned from the classroom experiment, time management, and students’ engagement can be underlined.Master's Thesis in System DynamicsGEO-SD351INTL-KMDMASV-SYSDYINTL-HFINTL-JUSINTL-PSYKINTL-MNINTL-MEDINTL-S