Execution time distributions in embedded safety-critical systems using extreme value theory

Several techniques have been proposed to upper-bound the worst-case execution time behaviour of programs in the domain of critical real-time embedded systems. These computing systems have strong requirements regarding the guarantees that the longest execution time a program can take is bounded. Some of those techniques use extreme value theory (EVT) as their main prediction method. In this paper, EVT is used to estimate a high quantile for different types of execution time distributions observed for a set of representative programs for the analysis of automotive applications. A major challenge appears when the dataset seems to be heavy tailed, because this contradicts the previous assumption of embedded safety-critical systems. A methodology based on the coefficient of variation is introduced for a threshold selection algorithm to determine the point above which the distribution can be considered generalised Pareto distribution. This methodology also provides an estimation of the extreme value index and high quantile estimates. We have applied these methods to execution time observations collected from the execution of 16 representative automotive benchmarks to predict an upper-bound to the maximum execution time of this program. Several comparisons with alternative approaches are discussed.The research leading to these results has received funding from the European Community’s Seventh Framework Programme [FP7/2007-2013] under the PROXIMA Project (grant agreement 611085). This study was also partially supported by the Spanish Ministry of Science and Innovation under grants MTM2012-31118 (2013-2015) and TIN2015-65316-P. Jaume Abella is partially supported by the Ministry of Economy and Competitiveness under Ramon y Cajal postdoctoral fellowship number RYC-2013- 14717.Peer ReviewedPostprint (author's final draft

Horizontal transmission of streptococcus mutans in schoolchildren

Objetive: The aim of this study was to analyze possible horizontal transmission patterns of S. mutans among 6-7-yr-old schoolchildren from the same class, identifying genotypes and their diversity and relationship with caries disease status. Study Design: Caries indexes and saliva mutans streptococci and lactobacilli counts were recorded in 42 schoolchildren. Mutans streptococci colonies were identified by means of biochemical tests and all S. mutans strains were genotyped by arbitrarily primed polymerase chain reaction. A child was considered free of S. mutans when it could not be isolated in 3 samples at 1-week intervals. Results: S. mutans was isolated in 30 schoolchildren: 20 having one genotype and 10 two genotypes. Higher mutans streptococci and caries index values were found in those with two genotypes. Five genotypes were isolated in more than 1 schoolchild and one of these was isolated in 3 schoolchildren. Our results suggest that horizontal transmission may take place. Conclusion: Schoolchildren aged 6-7 yrs may be the source of mutual transmission of S. mutans

Measurement-Based Worst-Case Execution Time Estimation Using the Coefficient of Variation

Extreme Value Theory (EVT) has been historically used in domains such as finance and hydrology to model worst-case events (e.g., major stock market incidences). EVT takes as input a sample of the distribution of the variable to model and fits the tail of that sample to either the Generalised Extreme Value (GEV) or the Generalised Pareto Distribution (GPD). Recently, EVT has become popular in real-time systems to derive worst-case execution time (WCET) estimates of programs. However, the application of EVT is not straightforward and requires a detailed analysis of, and customisation for, the particular problem at hand. In this article, we tailor the application of EVT to timing analysis. To that end, (1) we analyse the response time of different hardware resources (e.g., cache memories) and identify those that may lead to radically different types of execution time distributions. (2) We show that one of these distributions, known as mixture distribution, causes problems in the use of EVT. In particular, mixture distributions challenge not only properly selecting GEV/GPD parameters (i.e., location, scale and shape) but also determining the size of the sample to ensure that enough tail values are passed to EVT and that only tail values are used by EVT to fit GEV/GPD. Failing to select these parameters has a negative impact on the quality of the derived WCET estimates. We tackle these problems, by (3) proposing Measurement-Based Probabilistic Timing Analysis using the Coefficient of Variation (MBPTA-CV), a new mixture-distribution aware, WCET-suited MBPTA method that builds on recent EVT developments in other fields (e.g., finance) to automatically select the distribution parameters that best fit the maxima of the observed execution times. Our results on a simulation environment and a real board show that MBPTA-CV produces high-quality WCET estimates.The research leading to these results has received funding from the European Community’s FP7 [FP7/2007- 2013] under the PROXIMA Project (www.proxima-project.eu), grant 611085. This work has also been par- tially supported by the Spanish Ministry of Science and Innovation under grant TIN2015-65316-P and the HiPEAC Network of Excellence. Jaume Abella was partially supported by the Ministry of Economy and Competitiveness under Ramon y Cajal postdoctoral fellowship RYC-2013-14717.Peer ReviewedPostprint (author's final draft

Diagnostico del estado actual de consevación de Puya raimondii en Arequipa – Perù.

The diagnosis of the current state of conservation of Puya raimondii Hams in Arequipa, Perú. – The authors show the results of a survey carried out in Perù, Arequipe region, and Bolivia, on the geographical distribution of Puya raimondii Harms. After describing the systematic and nomenclature of the Andinian species, the study of the biological, ecological and conservation status of this endemic plant species has been performed, as well. They have also described the density population and the risk of genetic erosion caused of both natural and anthropic pressure. Finally they evaluated the use of this plant species as animal feeding, popular medicine traditional local use

Health state perception of people close to retirement age: Relationship with lifestyle habits and subjects' characteristics

Aim: Societal ageing increases the need for correct and healthy ageing to ensure the well-being of older adults. Practical strategies are needed to acquire healthy habits for the ageing process. This study aims to analyse the lifestyle habits of subjects who are retired or close to retirement and identify factors that could influence their perceived health and that could be related to these habits. Methods: A Spanish observational, descriptive, cross-sectional study of subjects close to retirement-age. Socio-demographic, family, work, leisure, social, and clinical-psychological indicators were evaluated. Results: 1,700 participants (581 employed; 714 retirees; 405 other-status) were included, average age 63 years, 52% women. Most reported a satisfactory social life (90%), were in live-in relationships (74%), non-smoking (80%), followed a Mediterranean diet (73%), and took medicines daily (70%). Perceived health (EQ-VAS) was 75.9/100, with low disability (12-WHODAS) (7.4/100) and moderate/severe depression. Women reported higher disability (p < 0.001) and depression (p < 0.001), a better social life, and healthier lifestyle, but lower physical/work activity. Retirees reported less depression, better social life, healthier lifestyle, higher physical/work activity, and better sleeping habits. The multivariate model showed a significant association of health-status with disability level, number of chronic diseases, sleep habits, exercise, diet, and alcohol consumption. When depression level was introduced, age and being a woman were also related. Conclusions: Retirement does not mean worse health but rather an opportunity to reinforce favourable health activities and improve lifestyle factors. Incorporating the differences related to gender and employment status in health-perception will facilitate the design of healthy ageing strategies.S

Tendencias bibliométricas de las publicaciones sobre resistencia a antimicrobianos en Escherichia coli en Perú de 2009-2019.

Antibiotic resistance is a growing problem worldwide. While the most visible aspect is the direct effect of antimicrobial resistance in clinical settings, this problem affects all microorganisms in all environments. Nevertheless, most of the data available on antibiotic resistance outside clinical settings are from high-income countries, with the current situation in most low- and middle-income countries remaining under-reported. Escherichia coli is considered a good marker of “antibiotic pressure” due to its cosmopolitan distribution. In this scenario, we selected E. coli as an appropriate microorganism to perform an initial bibliometric analysis of publications focused on antimicrobial resistance outside disease-causing microorganisms. Thus, the present manuscript performs an analysis of the studies reporting measurable levels of antibiotic resistance of E. coli not causing human disease in Peru published during the period from 2009-2019. Following a search in PubMed and Google, 35 documents were selected as reporting measurable data of antibiotic resistance. Of these, 8 (22.8%) were reported in thesis format. The mean delay between sampling and publishing in article format was 3.7 years, with one study having been published 18 years after sampling. The number of publications developed in Peru describing antimicrobial resistance levels in E. coli out of hospital settings in the period 2009-2019 is scarce. Of these, a relevant number is of unpublished thesis. These findings showing the gap of knowledge and lack of accessible data about antimicrobial resistance out of hospital environments. Efforts and strategies must be developed to fill this knowledge gap.La resistencia a antibióticos es un problema creciente a nivel mundial. Aunque el aspecto más visible es el efecto de la resistencia a antimicrobianos en ambientes hospitalarios, este problema afecta todos los ambientes. No obstante, la mayoría de los datos sobre resistencia antimicrobiana allende ambientes hospitalarios son de países de alta renta, siendo escasa la información sobre la situación en países de baja y media renta. Escherichia coli se considera un buen marcador de "presión antibiótica" debido a su distribución cosmopolita. En este escenario seleccionamos E. coli como microorganismo ideal para realizar un análisis bibliométrico de publicaciones, del periodo 2009-2019, que se centrasen en el estudio de la resistencia a antimicrobianos en E. coli no causantes de enfermedad en humanos en Perú. Tras una búsqueda en PubMed y Google, se seleccionaron 35 documentos que reportasen datos cuantificables de resistencia a antimicrobianos. De estos, 8 (22.8%) fueron tesis. La media de tiempo entre muestreo y publicación de artículo fue de 3.7 años, con un estudio habiéndose publicado 18 años después del muestreo. El número de publicaciones realizadas en Perú en el periodo 2009-2019 describiendo la resistencia a antimicrobianos de E. coli fuera del ámbito clínico es escaso. De estas, reseñar la presencia de un elevado número de tesis. Estos hechos muestran un vacío de conocimiento y una falta de datos accesibles sobre resistencia a antimicrobianos fuera de ámbitos hospitalarios. Se han de desarrollar esfuerzos y estrategias para acabar con este vacío de conocimiento

Future declines of Coronary Heart Disease mortality in England and Wales could counter the burden of population ageing

BACKGROUND:Coronary Heart Disease (CHD) remains a major cause of mortality in the United Kingdom. Yet predictions of future CHD mortality are potentially problematic due to population ageing and increase in obesity and diabetes. Here we explore future projections of CHD mortality in England & Wales under two contrasting future trend assumptions. METHODS:In scenario A, we used the conventional counterfactual scenario that the last-observed CHD mortality rates from 2011 would persist unchanged to 2030. The future number of deaths was calculated by applying those rates to the 2012-2030 population estimates. In scenario B, we assumed that the recent falling trend in CHD mortality rates would continue. Using Lee-Carter and Bayesian Age Period Cohort (BAPC) models, we projected the linear trends up to 2030. We validate our methods using past data to predict mortality from 2002-2011. Then, we computed the error between observed and projected values. RESULTS:In scenario A, assuming that 2011 mortality rates stayed constant by 2030, the number of CHD deaths would increase 62% or approximately 39,600 additional deaths. In scenario B, assuming recent declines continued, the BAPC model (the model with lowest error) suggests the number of deaths will decrease by 56%, representing approximately 36,200 fewer deaths by 2030. CONCLUSIONS:The decline in CHD mortality has been reasonably continuous since 1979, and there is little reason to believe it will soon halt. The commonly used assumption that mortality will remain constant from 2011 therefore appears slightly dubious. By contrast, using the BAPC model and assuming continuing mortality falls offers a more plausible prediction of future trends. Thus, despite population ageing, the number of CHD deaths might halve again between 2011 and 2030. This has implications for how the potential benefits of future cardiovascular strategies might best be calculated and presented

Clinical Outcomes of Patients with Chronic Neuropathic Form of Gaucher Disease in the Spanish Real-World Setting: A Retrospective Study

Gaucher disease type 3; Clinical manifestations; MutationsEnfermedad de Gaucher tipo 3; Manifestaciones clínicas; MutacionesMalaltia de Gaucher tipus 3; Manifestacions clíniques; MutacionsThis was a retrospective, multicenter study that aimed to report the characteristics of type 3 Gaucher disease (GD3) patients in Spain, including the genotype, phenotype, therapeutic options, and treatment responses. A total of 19 patients with GD3 from 10 Spanish hospitals were enrolled in the study (14 men, 5 women). The median age at disease onset and diagnosis was 1 and 1.2 years, respectively, and the mean age at follow-up completion was 12.37 years (range: 1-25 years). Most patients exhibited splenomegaly (18/19) and hepatomegaly (17/19) at the time of diagnosis. The most frequent neurological abnormalities at onset were psychomotor retardation (14/19) and extrinsic muscle disorders (11/19), including oculomotor apraxia, supranuclear palsy, and strabismus. The L444P (c.1448T>C) allele was predominant, with the L444P (c.1448T>C) homozygous genotype mainly associated with visceral manifestations like hepatosplenomegaly, anemia, and thrombocytopenia. All patients received enzyme replacement therapy (ERT); other treatments included miglustat and the chaperone (ambroxol). Visceral manifestations, including hepatosplenomegaly and hematological and bone manifestations, were mostly controlled with ERT, except for kyphosis. The data from this study may help to increase the evidence base on this rare disease and contribute to improving the clinical management of GD3 patients.This research was funded by Sanofi Spain