599 research outputs found

    Partnering with Students to Connect Students

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    Too often outreaches and interventions designed to support students transitioning to higher education, are developed by academics who may not have a full understanding of the complexity and diversity of their students’ realities. This disconnect explains why, in most cases, interventions are reactive instead of proactive. In this article, we draw on our experiences in terms of the design and implementation of a Student Resource Centre (SRC) to advocate for student and staff collaborative design. The student-run initiative works with students as partners to constitute and operationalise an innovative near-peer mentoring and support space. The mixed-methods study draws on social-cultural learning theory on student engagement and reflective practice tools. We explain how a student’s sense of belonging is central to their success, progression, and graduation. This article highlights the need to contextualise and personalise institutional support for students

    Causal Factors of Breeding Success and Frequency in Threatened Grassland Birds on the Ingula Nature Reserve, South Africa

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    The high-altitude grasslands covering the eastern escarpment of South Africa is one of the country’s most valuable habitats for biodiversity, livestock and water production. The habitat hosts several threatened bird species including endangered species such as the Rudd\u27s Lark (Heteromirafra ruddi) and Grey Crowned Crane (Balearica regulorum), and vulnerable species such as the Blue Crane (Grus paradisea), Wattled Crane (Bugeranus carunculatus), Southern Bald Ibis (Geronticus calvus), and Yellow-breasted Pipit (Anthus chloris). Avian research and monitoring have been ongoing within the recently declared Ingula Nature Reserve for more than 15 years as part of the activities of the Ingula Partnership - a partnership between BirdLife South Africa, Eskom Holdings SOC Ltd and the Middelpunt Wetland Trust - with the objective of effectively conserving birds and their habitat surrounding the Ingula Pumped Storage Scheme development. Avian monitoring on Ingula refocused in 2014 to confirm the presence of threatened species on site, followed by the determination of the breeding status of these species. An initiative was then launched to assess the breeding frequency and success of each identified species. Breeding monitoring for 13 out of the 24 occurring threatened species commenced in 2014 and was conducted for five consecutive seasons. Breeding success per season was measured in relation to the grassland management regime of that season (including both fire and grazing), as well as weather data, adjusting for dry and wet seasons. Results confirm that various grassland management regimes directly influenced the initiation of breeding activities and density of several of the species studied, while others’ breeding success and frequency were more dependent on macro-weather patterns (including climate change) and fire frequency and timing. These results have direct implications for the management of highland grasslands and associated species in the given region

    Nitro­furan­toin methanol monosolvate

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    The anti­biotic nitro­furan­toin {systematic name: (E)-1-[(5-nitro-2-fur­yl)methyl­idene­amino]­imidazolidine-2,4-dione} crys­tallizes as a methanol monosolvate, C8H6N4O5·CH4O. The nitro­furan­toin mol­ecule adopts a nearly planar conformation (r.m.s. deviation = 0.0344 Å). Hydrogen bonds involve the co-operative N—H⋯O—H⋯O heterosynthons between the cyclic imide of nitro­furan­toin and methanol O—H groups. There are also C—H⋯O hydrogen bonds involving the nitro­furan­toin mol­ecules which support the key hydrogen-bonding synthon. The overall crystal packing is further assisted by weak C—H⋯O inter­actions, giving a herringbone pattern

    The Born Rule as Dutch-Book Coherence (and only a little more)

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    The subjective Bayesian interpretation of probability asserts that the rules of the probability calculus follow from the normative principle of Dutch-book coherence: A decision-making agent should not assign probabilities such that a series of monetary transactions based on those probabilities would lead them to expect a sure loss. Similarly, the subjective Bayesian interpretation of quantum mechanics (QBism) asserts that the Born rule is a normative rule in analogy to Dutch-book coherence, but with the addition of one or more empirically based assumptions -- i.e., the ``only a little more'' that connects quantum theory to the particular characteristics of the physical world. Here we make this link explicit for a conjectured representation of the Born rule which holds true if symmetric informationally complete POVMs (or SICs) exist for every finite dimensional Hilbert space. We prove that an agent who thinks they are gambling on the outcomes of measurements on a sufficiently quantum-like system, but refuses to use this form of the Born rule when placing their bets is vulnerable to a Dutch book. The key property for being sufficiently quantum-like is that the system admits a symmetric reference measurement, but that this measurement is not sampling any hidden variables.Comment: 13 pages, 35 references, 3 appendices, 1 miserable year finally over and done wit

    Development of artificial neural network models for paediatric critical illness in South Africa

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    OBJECTIVES: Failures in identification, resuscitation and appropriate referral have been identified as significant contributors to avoidable severity of illness and mortality in South African children. In this study, artificial neural network models were developed to predict a composite outcome of death before discharge from hospital or admission to the PICU. These models were compared to logistic regression and XGBoost models developed on the same data in cross-validation. DESIGN: Prospective, analytical cohort study. SETTING: A single centre tertiary hospital in South Africa providing acute paediatric services. PATIENTS: Children, under the age of 13 years presenting to the Paediatric Referral Area for acute consultations. OUTCOMES: Predictive models for a composite outcome of death before discharge from hospital or admission to the PICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: 765 patients were included in the data set with 116 instances (15.2%) of the study outcome. Models were developed on three sets of features. Two derived from sequential floating feature selection (one inclusive, one parsimonious) and one from the Akaike information criterion to yield 9 models. All developed models demonstrated good discrimination on cross-validation with mean ROC AUCs greater than 0.8 and mean PRC AUCs greater than 0.53. ANN1, developed on the inclusive feature-et demonstrated the best discrimination with a ROC AUC of 0.84 and a PRC AUC of 0.64 Model calibration was variable, with most models demonstrating weak calibration. Decision curve analysis demonstrated that all models were superior to baseline strategies, with ANN1 demonstrating the highest net benefit. CONCLUSIONS: All models demonstrated satisfactory performance, with the best performing model in cross-validation being an ANN model. Given the good performance of less complex models, however, these models should also be considered, given their advantage in ease of implementation in practice. An internal validation study is now being conducted to further assess performance with a view to external validation

    Elicitation of domain knowledge for a machine learning model for paediatric critical illness in South Africa

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    OBJECTIVES: Delays in identification, resuscitation and referral have been identified as a preventable cause of avoidable severity of illness and mortality in South African children. To address this problem, a machine learning model to predict a compound outcome of death prior to discharge from hospital and/or admission to the PICU was developed. A key aspect of developing machine learning models is the integration of human knowledge in their development. The objective of this study is to describe how this domain knowledge was elicited, including the use of a documented literature search and Delphi procedure. DESIGN: A prospective mixed methodology development study was conducted that included qualitative aspects in the elicitation of domain knowledge, together with descriptive and analytical quantitative and machine learning methodologies. SETTING: A single centre tertiary hospital providing acute paediatric services. PARTICIPANTS: Three paediatric intensivists, six specialist paediatricians and three specialist anaesthesiologists. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The literature search identified 154 full-text articles reporting risk factors for mortality in hospitalised children. These factors were most commonly features of specific organ dysfunction. 89 of these publications studied children in lower- and middle-income countries. The Delphi procedure included 12 expert participants and was conducted over 3 rounds. Respondents identified a need to achieve a compromise between model performance, comprehensiveness and veracity and practicality of use. Participants achieved consensus on a range of clinical features associated with severe illness in children. No special investigations were considered for inclusion in the model except point-of-care capillary blood glucose testing. The results were integrated by the researcher and a final list of features was compiled. CONCLUSION: The elicitation of domain knowledge is important in effective machine learning applications. The documentation of this process enhances rigour in such models and should be reported in publications. A documented literature search, Delphi procedure and the integration of the domain knowledge of the researchers contributed to problem specification and selection of features prior to feature engineering, pre-processing and model development

    The lesson of causal discovery algorithms for quantum correlations: Causal explanations of Bell-inequality violations require fine-tuning

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    An active area of research in the fields of machine learning and statistics is the development of causal discovery algorithms, the purpose of which is to infer the causal relations that hold among a set of variables from the correlations that these exhibit. We apply some of these algorithms to the correlations that arise for entangled quantum systems. We show that they cannot distinguish correlations that satisfy Bell inequalities from correlations that violate Bell inequalities, and consequently that they cannot do justice to the challenges of explaining certain quantum correlations causally. Nonetheless, by adapting the conceptual tools of causal inference, we can show that any attempt to provide a causal explanation of nonsignalling correlations that violate a Bell inequality must contradict a core principle of these algorithms, namely, that an observed statistical independence between variables should not be explained by fine-tuning of the causal parameters. In particular, we demonstrate the need for such fine-tuning for most of the causal mechanisms that have been proposed to underlie Bell correlations, including superluminal causal influences, superdeterminism (that is, a denial of freedom of choice of settings), and retrocausal influences which do not introduce causal cycles.Comment: 29 pages, 28 figs. New in v2: a section presenting in detail our characterization of Bell's theorem as a contradiction arising from (i) the framework of causal models, (ii) the principle of no fine-tuning, and (iii) certain operational features of quantum theory; a section explaining why a denial of hidden variables affords even fewer opportunities for causal explanations of quantum correlation

    Studies on the pathology of heartwater Cowdria (Rickettsia) ruminantium, Cowdry, 1926 I. Neuropathological changes

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    The most significant pathological changes in the central nervous system of 27 cases of heartwater are described. In addition to leucostasis and cell infiltration in the perivascular and subarachnoid spaces described previously, the following changes were noticed:- Swollen axis-cylinders, microcavitation and focal necrosis of the cerebellar cortex; degenerative and necrotic changes in the neuroglia accompanied by the formation of P.A.S. positive intracytoplasmic granules and globules; the accumulation of P.A.S. positive globules in the V.R. spaces; choriomeningeal oedema and fibrinous choriomeningitis; haemorrhages, oedema and vascular changes. Evidence is submitted in favour of the perivascular globules being proteinaceous and of glial origin.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    Task shifting from doctors to non-doctors for initiation and maintenance of antiretroviral therapy

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    CITATION: Kredo, T. et al. 2014. Task shifting from doctors to non-doctors for initiation and maintenance of antiretroviral therapy. Cochrane Database of Systematic Reviews, 7:CD007331, doi:10.1002/14651858.CD007331.pub3.The original publication is available at https://www.cochranelibrary.comBackground: The high levels of healthcare worker shortage is recognised as a severe impediment to increasing patients’ access to antiretroviral therapy. This is particularly of concern where the burden of disease is greatest and the access to trained doctors is limited.This review aims to better inform HIV care programmes that are currently underway, and those planned, by assessing if task-shifting care from doctors to non-doctors provides both high quality and safe care for all patients requiring antiretroviral treatment. Objectives: To evaluate the quality of initiation and maintenance of HIV/AIDS care in models that task shift care from doctors to non-doctors.Publisher's versio

    Aggregation, impaired degradation and immunization targeting of amyloid-beta dimers in Alzheimer’s disease: a stochastic modelling approach

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    Background Alzheimer’s disease (AD) is the most frequently diagnosed neurodegenerative disorder affecting humans, with advanced age being the most prominent risk factor for developing AD. Despite intense research efforts aimed at elucidating the precise molecular underpinnings of AD, a definitive answer is still lacking. In recent years, consensus has grown that dimerisation of the polypeptide amyloid-beta (Aß), particularly Aß42, plays a crucial role in the neuropathology that characterise AD-affected post-mortem brains, including the large-scale accumulation of fibrils, also referred to as senile plaques. This has led to the realistic hope that targeting Aß42 immunotherapeutically could drastically reduce plaque burden in the ageing brain, thus delaying AD onset or symptom progression. Stochastic modelling is a useful tool for increasing understanding of the processes underlying complex systems-affecting disorders such as AD, providing a rapid and inexpensive strategy for testing putative new therapies. In light of the tool’s utility, we developed computer simulation models to examine Aß42 turnover and its aggregation in detail and to test the effect of immunization against Aß dimers. Results Our model demonstrates for the first time that even a slight decrease in the clearance rate of Aß42 monomers is sufficient to increase the chance of dimers forming, which could act as instigators of protofibril and fibril formation, resulting in increased plaque levels. As the process is slow and levels of Aβ are normally low, stochastic effects are important. Our model predicts that reducing the rate of dimerisation leads to a significant reduction in plaque levels and delays onset of plaque formation. The model was used to test the effect of an antibody mediated immunological response. Our results showed that plaque levels were reduced compared to conditions where antibodies are not present. Conclusion Our model supports the current thinking that levels of dimers are important in initiating the aggregation process. Although substantial knowledge exists regarding the process, no therapeutic intervention is on offer that reliably decreases disease burden in AD patients. Computer modelling could serve as one of a number of tools to examine both the validity of reliable biomarkers and aid the discovery of successful intervention strategies
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