Extraction of Pertinent Subsets from Time-Frequency Representations for Detection and Recognition Purposes

International audienceA time-frequency representation can highlight non-stationarities in a signal. We propose to extract subsets from the Time-Frequency Representation (TFR) for classification or recognition purposes. We developed two approaches. The first one is developed for TFRs obtained from the Short Time Fourier Transform or the gliding Minimum Variance method. The extraction of compact subsets is viewed as a segmentation of the TFR, which is performed by morphological filtering and Watershed segmentation. The second approach is developed when the TFR has been obtained using parametric estimators. We consider a hybrid estimator, the ARCAP method, and use a Kalman filter trajectory tracker to extract spectral lines. The proposed methods are illustrated by examples on natural signals : dolphin whistle acoustical signals, cavitation signals and seismic signals produced by snow avalanches

Improving the comparability of insolvency predictions

This working paper aims at improving the comparability of forecast quality measures of insolvency prediction studies. For this purpose, in a first step commonly used accuracy measures for categorial, ordinal and cardinal insolvency predictions are presented. It will be argued, that ordinal measures are the most suitable measures for sample spanning comparisons concerning predictive power of rating models, as they are not affected by sample default rates. A method for transforming cardinal into ordinal accuracy measures is presented, by which comparisons of insolvency prediction results of older and present-day studies are enabled. In the second part of the working paper an overview of influencing variables – aside from the quality of the insolvency prediction methods – is given, which affect the accuracy measures presented in the first part of the paper and thus impair sample spanning comparison of empirically obtained forecast quality results. In this context, methods for evaluating information losses that are attributable to the discretization of continuous rating scales or preselection of portfolios are developed. Measure results of various insolvency prognosis studies are envisaged and compared with three benchmarks. First benchmark is the accuracy that can be achieved solely by taking into account legal status and industry classification of corporations. The second benchmark is the univariate prognosis accuracy of single financial ratios. As third benchmark, ALTMAN’s Z-score model is examined, a multivariate insolvency prediction model, that is currently used as reference rating model in many empirical studies. It turns out, however, that the Z-score’s forecast quality is so discontenting, that its application is not recommendable. Instead it is suggested to use those rating models that are cited in this discussion paper, which are fully documented and which therefore can be rebuilt and directly applied to any desired data sample. If applied to the respective target groups, their performance matches with the performance of commercial rating systems, like bureau and business scores for rather small companies, middle market rating models for SMB, or agency ratings for large public companies.financial ratio analysis, corporate bankruptcy prediction, forecast validation, accuracy ratio, information entropy, sample selection, rating granularity

Development of techniques for the assessment of climate change impacts on estuaries : a hydrological perspective.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.Global climate change is a naturally occurring phenomenon, influencing weather and climate patterns. However, the greatest cause for concern at present is the rate at which climate change is currently occurring. Natural shifts in climate take place over a period of many thousands of years, not in a matter of decades, which is what is occurring at present. In South Africa, climate change is projected to have different regional effects, which in turn could impact on the components of the terrestrial hydrological system, such as land use. The alteration of the catchment upstream of the estuaries could affect the quantity and quality of streamflows entering estuaries. This could impact negatively upon estuaries, thereby reducing the considerable biodiversity in estuaries and the ecosystems goods and services provided by estuaries which would reduce the significant revenue provided by these systems. The research undertaken in this project investigates the possible effects of climate change, and changes in upstream land use on freshwater inflows into estuarine ecosystems using a daily hydrological model. Owing to the regionality of climate change in South Africa 10 estuaries in different climatic regions were selected for this investigation. Climate output from five GCMs under the SRES A2 climate scenario for the present (1971 – 1990), intermediate (2046 – 2065) and distant future (2081 – 2100) periods was used as input for the selected climate input. Results of these simulations show that the eastern regions of South Africa may experience considerable increases in the occurrence of high intensity rainfall events into the future. This could influence the abiotic factors of the system which may impact upon the biotic components of estuaries, as these systems are physically controlled. In the western regions the difference of the magnitude of flows between present and projected future is minimal. However, projected increases in temperature could influence evaporation, thereby decreasing future flows into estuaries. This, in some instances, may result in systems turning hyper-saline, which could have far reaching implications, both ecologically and economically. Additionally, an investigation, as to the possible effects of irrigation and climate change combined on flows entering and breaching events of the Klein estuary, was undertaken. Hence, simulations including and excluding irrigation routines have been completed. Results from these simulations illustrate the detrimental effects of irrigation into the future periods, especially during 1 in 10 low flow years, when flows into the Klein estuary cease completely. Breaching event results illustrate that climate change could have a negative impact on this estuarine system as the number of events decreases into distant future period. The addition of agricultural abstractions decreases the number of breaching events markedly. Therefore, the link between the marine and terrestrial hydrological systems is lost which could, if this estuary is isolated from the ocean for an extended period of time, become extremely detrimental to the ecological integrity of the Klein estuary. This highlights the value and vulnerabilities of estuarine ecosystems in South Africa to future climate and upstream land use changes

Projected impacts of climate change on water quality constituents and implications for adaptive management.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.The past few decades have seen, amongst other topical environmental issues, increased concerns regarding the imminent threat of global warming and the consequential impacts of climate change on environmental, social and economic systems. Numerous groundbreaking studies conducted independently and cooperatively have provided abundant and conclusive evidence that global climates are changing and that these changes will almost certainly impact natural and socio-economic systems. Increased global change pressures, which include, inter alia, climate change, have increased concerns over the supply of adequate quality freshwater. There is an inadequate body of knowledge pertaining to linking basic hydrological processes which drive water quality (WQ) variability with projected climate change. Incorporating such research into policy development and governance with the intention of developing adaptive WQ management strategies is also overlooked. Thus, the aim of this study was the assessment of projected climate change impacts on selected WQ constituents in the context of agricultural non-point source pollution and the development of the necessary adaptation strategies that can be incorporated into WQ management, policy development and governance. This assessment was carried out in the form of a case study in the Mkabela Catchment near Wartburg in KwaZulu-Natal, South Africa. The research involved applying climate change projections derived from seven downscaled Global Circulation Models (GCMs) used in the Fourth Intergovernmental Panel on Climate Change (IPCC) Assessment Report, in the ACRU-NPS water quality model to assess the potential impacts on selected water quality constituents (viz. sediment, nitrogen and phosphorus). Results indicated positive correlations between WQ related impacts and contaminant migration as generated from agricultural fertilizer applications. ACRU-NPS simulations indicated increases in runoff and associated changes in WQ variable generation and migration from upstream sources in response to downscaled GCM projections. However, there was limited agreement found between the simulations derived from the various downscaled GCM projections in regard to the magnitude and direction (i.e. percent changes between present and the future) of these changes in WQ variables. The rainfall distribution analyses conducted on a daily time-step resolution for each selected GCM also showed limited consistency between the GCM projections regarding rainfall changes between the present and the future. The implication was that since hydrological and climate change modelling can inform adaptation under climate change. However, adaptation to climate change in water quality management and policy development is going to require approaches that fully recognise the uncertainties presented by climate change and the associated modelling thereof. It was also considered crucial that equal attention be given to both climate change and natural variability, in order to ensure that adaptation strategies remain robust and effective under conditions of climate change and its respective uncertainties

Linkages between selected hydrological ecosystem services and land use changes, as indicated by hydrological responses : a case study on the Mpushini/Mkhondeni Catchments, South Africa.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2014.Nature provides essential services to humans, including climate regulation, water provisioning and regulation. These so-called ecosystem services have economical, societal and environmental value. This research aims at improving the knowledge on the linkages between selected hydrological ecosystem services and current and proposed land uses within the water-limited Mpushini/Mkhondeni Catchments in South Africa. The research contributes to the recognition of feedback and linkages within the complex ecological-human system, so that informed land use decisions can be made. The research aim is achieved by first reviewing the literature on hydrological ecosystem services, land use in an ecosystem services context and the links between the two. The study area is then sub-delineated into land use determined hydrological response units for baseline natural land cover, as well as for current and proposed land use scenarios. Using an appropriate model, selected hydrological processes are simulated in order to isolate the effects of individual land uses on hydrological responses, both on a local and a more catchment-wide scale. Various land uses were found to affect hydrological responses, such as runoff and its components of stormflows and baseflows, as well as transpiration and sediment yields, differently. These responses were found to be suitable indicators of selected ecosystem services such as water provisioning or flow regulation. Irrigation and high biomass crops, such as sugarcane and wattle plantations were found to reduce downstream water provisioning services. Degraded lands were found to reduce physical water quality through increased sediment yield, to reduce water provisioning during low flow periods, while the degraded lands increased stormflows, thereby reducing regulation of high flows. Urban land uses were found to significantly increase runoff, with increased impervious areas causing a shift from evaporation and transpiration towards runoff. Stormflows increased, with high flow regulation being reduced. Baseflows increased as well, as a result of a spill-over of runoff from impervious to pervious urban areas, which led to increased low flow regulation. In addition, in this study area urban return flows are generated from externally sourced water, further increasing streamflows and especially low flows. While urban areas showed an increase in downstream water quantity provision, the water quality was reduced. The combined effects of the current land use mosaic on the annual streamflows partially cancel each other out, while the proposed urbanisation dominated hydrological responses. Influences of various land uses on hydrological ecosystem services were thereby shown, which contributes to a better understanding of the linkages between the two

Comparative Analysis of CSR Disclosure and Its Impact on Financial Performance in the GCC Islamic Banks

The concept of corporate social responsibility (CSR) has been developed and promoted since the 1960s, as part of the changing nature of the corporate working environment, with the objective of corporations having their share in contributing to social good in the economy and in society. CSR, as a concept and practice, is directly related to Islamic banking operations, since Islamic finance is located within Islamic moral economy, which essentialises social justice. The Islamic banking sector, therefore, is required by the nature of Islamic injunctions and principles to produce outcomes that are in line with the larger social expectations, namely CSR, with the objective of delivering long-term economic benefits but also to help society. The main aim of this research, therefore, is to analyse the CSR attitudes and practices of Islamic banks in the GCC region through their CSR disclosure practices. This research further aims to examine empirically the impact of CSR disclosure practices of the GCC Islamic banks on their financial performance. In fulfilling the research aim, annual reports of GCC Islamic banks for the period 2000- 2011 are scored by using content analysis. The CSR disclosure index is constructed based on the eight dimensions developed for this purpose. Despite the high expectations of full disclosure and accountability, the research findings do not produce encouraging results in terms of CSR or the social outcome of Islamic banks in the GCC region. The majority of GCC Islamic banks disclose significantly less than required, as CSR disclosure indices for all the Islamic banks remain very low in comparison to the overall score but also for each of the CSR dimensions included in the indices. While examining the impact of CSR disclosure practices on financial performance of Islamic banks in the GCC region, the results indicate the positive relationship between CSR disclosure and financial performance. These results are in line with the set hypotheses and discussed theoretical framework that predict a positive link between corporate social and financial performance in the Islamic banking industry

The Australian Handbook for Careers in Psychological Science

Despite psychology being one of the most popular undergraduate programs, students often report not knowing how training in psychology relates to careers. With chapters written by experts across Australia, this book explores just some of the many ways that students can apply their training in psychological science across a variety of careers and sectors

Rapid induction of the unfolded protein response and apoptosis by synthetic oestrogen mimic TTC-352 and naturally-occurring oestrogen oestetrol for the treatment of endocrine-resistant breast cancer

Patients with long-term oestrogen-deprived (LTED) breast cancer (BC), after resistance to tamoxifen or aromatase inhibitors develops, can experience tumour regression when treated with oestrogens. Oestrogen’s anti-tumour effect is attributed to apoptosis via the oestrogen receptor (ER). Oestrogen treatment can have unpleasant gynecological, as well as non-gynecological adverse events, and thus the development of safer oestrogenic agents remains a clinical priority. Here, we study synthetic selective oestrogen mimics (SEMs) BMI-135 and TTC-352, and the naturally-occurring oestrogen oestetrol (E4), which are proposed as safer oestrogenic agents compared to 17β-oestradiol (E2), for the treatment of endocrine-resistant BC. TTC-352 and E4 are being evaluated in advanced BC clinical trials. Cell viability assays, real-time polymerase chain reaction, luciferase reporter assays, chromatin immunoprecipitation, immunoblotting, ERE DNA pull downs, mass spectrometry, X-ray crystallography, docking and molecular dynamics simulations, live cell microscopic imaging and analysis, and annexin V staining, were conducted in 11 biologically-different patient-derived BC models and a human endometrial cancer model. Results were compared with the potent full agonist E2, less potent full agonists oestrone and oestriol, the benchmark partial agonist triphenylethylene bisphenol (BPTPE), antagonists or Selective ER modulators 4-hydroxytamoxifen, endoxifen, and raloxifene, and Selective ER Downregulator fulvestrant. This work reports ERα’s regulation and coregulators’ binding profiles with SEMs and E4. It also describes SEMs and E4’s pharmacology as weak full agonists, and anti-tumour molecular mechanisms through the unfolded protein response (UPR) and apoptosis. These studies highlight the phenolic OH of TTC-352’s benzothiophene scaffold and E4’s A ring that yield an H-bond with Glu353, which allows Asp351-to-helix 12 (H12) interaction; sealing ERα’s ligand binding domain (LBD), recruiting E2-enriched coactivators, and triggering rapid ERα-induced UPR and apoptosis, as the basis of its anti-cancer properties. By contrast, BPTPE’s phenolic OH yields an H-Bond with Thr347, which disrupts Asp351-to-H12 interaction; not sealing ERα’s LBD properly, not recruiting many E2-enriched coactivators, and triggering delayed ERα-induced UPR and apoptosis. Such delay might increase the risk of metastasis, clonal evolution, and acquired resistance. Overall, this work concludes the structural, pharmacological, and mechanistic constituents of an effective oestrogen for the treatment of LTED advanced BC