Lessons for the past : Third World evidence and the reinterpretation of developed world mortality declines

Measles is the largest single killing infection of children in the world, and it is likely that its toll is heightened by the occurrence of a serious delayed effect of early infection. Variations in measles mortality, and in the seriousness of infection, have often been explained in terms of nutritional factors, but intercountry comparisons within the Third World fail to bear this out. In this paper an alternative interpretation is developed, based on the severity of the infective dose to which individuals are exposed. It is shown that this can account for a wide variety of observations which are inexplicable on the nutritional hypothesis, and can also explain the severity of virginsoil epidemics without reference to the effects of genetic selection. The exposure hypothesis predicts that measles vaccination should have a marked effect on childhood mortality as a whole, and this prediction is born out in practice. The success of this interpretation has important implications for our understanding of historical mortality declines in the developed countries, particularly the decline in smallpox mortality

Changing pattern of malaria in Bissau, Guinea Bissau.

OBJECTIVE: To describe the epidemiology of malaria in Guinea-Bissau, in view of the fact that more funds are available now for malaria control in the country. METHODS: From May 2003 to May 2004, surveillance for malaria was conducted among children less than 5 years of age at three health centres covering the study area of the Bandim Health Project (BHP) and at the outpatient clinic of the national hospital in Bissau. Cross-sectional surveys were conducted in the community in different malaria seasons. RESULTS: Malaria was overdiagnosed in both health centres and hospital. Sixty-four per cent of the children who presented at a health centre were clinically diagnosed with malaria, but only 13% of outpatient children who tested for malaria had malaria parasitaemia. Only 44% (963/2193) of children admitted to hospital with a diagnosis of malaria had parasitaemia. The proportion of positive cases increased with age. Among hospitalized children with malaria parasitaemia, those less than 2 years old were more likely to have moderate anaemia (RR = 1.27; 95% CI: 1.02-1.56) (P = 0.03) or severe anaemia (RR = 1.67; 95% CI: 1.25-2.24) (P = 0.0005) than older children. The prevalence of malaria parasitaemia in the community was low (3%, 53/1926). CONCLUSION: In Bissau, the prevalence of malaria parasitaemia in the community is now low and malaria is over-diagnosed in health facilities. Laboratory support will be essential to avoid unnecessary use of the artemisinin combination therapy which is now being introduced as first-line treatment in Bissau with support from the Global Fund

Mortality associated with HIV-1, HIV-2, and HTLV-I single and dual infections in a middle-aged and older population in Guinea-Bissau

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No long-term excess mortality after measles infection : a community study from Senegal

Because measles immunization has been found in all studies to reduce mortality with more than the share of deaths attributed to acute measles, the authors examined mortality after measles infection in a study in a rural area of Senegal that included 6924 unimmunized children, of whom 1118 developped measles. Age-adjusted post-measles mortality was similar to the mortality of unvaccinated, uninfected children (mortality ratio (MR) = 1.04, 95% confidence interval (CI) 0.80-1.35). When controlling for source of infection, mortality rate was significantly different for children who contracted measles from a person outside the home (index cases vs. unvaccinated, uninfected MR = 0.27 95% CI 0.009-0.85) and for children infected at home (secondary cases vs. unvaccinated, uninfected MR = 1.10 95% CI 0.80-1.51). Hence, secondary cases had markedly higher long-term mortality than did index cases (MR = 4.13 95% CI 1.26-13.58). These estimates were essentially unchanged when the effects of season, period, separation from mother, size of community, and size of compound were investigated using a multivariate Cox regression model. The authors conclude that measles infection was not associated with increased mortality after the acute phase of infection and that index cases had lower mortality than uninfected, unvaccinated children. The reduction in mortality after measles immunization can therefore not be explained by the prevention of post-measles mortality

Advancing touch-based continuous authentication by automatically extracting user behaviours

Smartphones provide convenient access to online banking, social media, photos, and entertainment, all of which have become integral to our daily lives. However, this mobile nature also opens up new avenues for unauthorised access to user data. To combat this, device manufacturers often provide a screen lock mechanism. Yet, traditional lock screen authentication can be inconvenient and only offers protection at the point of user verification. Therefore, this thesis demonstrates the potential of touch-based behavioural biometrics for continuous authentication, which could significantly enhance smartphone security. The behaviours studied here are exclusively modelled from smartphone touchscreen inputs obtained from publicly available data, and the results show promising effectiveness in addressing security concerns.The initial objective was to assess, through feature selection, the behaviours universally exhibited by users and those unique to individuals to improve the performance of the 60 different continuous authentication models being tested. Of the 30 features used over five feature selection methods, results showed that features related to pressure appeared in 81% of models, demonstrating their importance for most users while not negatively affecting performance when non-important features were removed. The following research sought to model users independent of their directional navigation and instead rely more on these essential features. In this field, several models are typically produced for each user depending on gesture direction when testing authentication methods. However, since features describe behaviour, this thesis demonstrates that the proposed single omni-directional model can be employed while prioritising lesser complex hyperparameters. Results show that using an omni-directional model to evaluate 35 users can achieve an AUC score of 89% and 17.9% EER when authenticating using five gestures while outperforming more complex bi-directional techniques. Furthermore, the omni-directional model performs better when using the oldest feature set than more recent efforts in engineering new features.When considering the necessary prioritisation of features unique to individuals, it becomes immediately apparent that engineering and evaluating these manually is impossible at scale. To address this, this thesis proposes a move towards automatic feature extraction through the innovative TouchEncoding method. This method transforms touch behaviour into image encodings that enable computer vision to authenticate users. The results of this approach were superior to all the related work, with AUC scores of 96.7% and EER of 8.5% across 74 users while authenticating on a single gesture. The performance further improved to 99.1% AUC and 3.6% EER when authenticating using five gestures. This underscores the effectiveness and superiority of the TouchEncoding method, paving the way for future work in this area

A randomized trial of a standard dose of Edmonston-Zagreb measles vaccine given at 4.5 months of age: effect on total hospital admissions.

Observational studies and trials from low-income countries indicate that measles vaccine has beneficial nonspecific effects, protecting against non-measles-related mortality. It is not known whether measles vaccine protects against hospital admissions. Between 2003 and 2007, 6417 children who had received the third dose of diphtheria, tetanus, and pertussis vaccine were randomly assigned to receive measles vaccine at 4.5 months or no measles vaccine; all children were offered measles vaccine at 9 months of age. Using hospital admission data from the national pediatric ward in Bissau, Guinea-Bissau, we compared admission rates between enrollment and the 9-month vaccination in Cox models, providing admission hazard rate ratios (HRRs) for measles vaccine versus no measles vaccine. All analyses were conducted stratified by sex and reception of neonatal vitamin A supplementation (NVAS). Before enrollment the 2 groups had similar admission rates. Following enrollment, the measles vaccine group had an admission HRR of 0.70 (95% confidence interval [CI], .52-.95), with a ratio of 0.53 (95% CI, .32-.86) for girls and 0.86 (95% CI, .58-1.26) for boys. For children who had not received NVAS, the admission HRR was 0.53 (95% CI, .34-.84), with an effect of 0.30 (95% CI, .13-.70) for girls and 0.73 (95% CI, .42-1.28) for boys (P = .08, interaction test). The reduction in admissions was separately significant for measles infection (admission HRR, 0 [95% CI, 0-.24]) and respiratory infections (admission HRR, 0.37 [95% CI, .16-.89]). Early measles vaccine may have major benefits for infant morbidity patterns and healthcare costs. Clinical trials registration NCT00168558

An Omnidirectional Approach to Touch-based Continuous Authentication

This paper focuses on how touch interactions on smartphones can provide a continuous user authentication service through behaviour captured by a touchscreen. While efforts are made to advance touch-based behavioural authentication, researchers often focus on gathering data, tuning classifiers, and enhancing performance by evaluating touch interactions in a sequence rather than independently. However, such systems only work by providing data representing distinct behavioural traits. The typical approach separates behaviour into touch directions and creates multiple user profiles. This work presents an omnidirectional approach which outperforms the traditional method independent of the touch direction - depending on optimal behavioural features and a balanced training set. Thus, we evaluate five behavioural feature sets using the conventional approach against our direction-agnostic method while testing several classifiers, including an Extra-Tree and Gradient Boosting Classifier, which is often overlooked. Results show that in comparison with the traditional, an Extra-Trees classifier and the proposed approach are superior when combining strokes. However, the performance depends on the applied feature set. We find that the TouchAlytics feature set outperforms others when using our approach when combining three or more strokes. Finally, we highlight the importance of reporting the mean area under the curve and equal error rate for single-stroke performance and varying the sequence of strokes separately