2,316 research outputs found
En-route: on enabling resource usage testing for autonomous driving frameworks
Software resource usage testing, including execution time bounds and memory, is a mandatory validation step during the integration of safety-related real-time systems. However, the inherent complexity of Autonomous Driving (AD) systems challenges current practice for resource usage testing. This paper exposes the difficulties to perform resource usage testing for AD frameworks by analyzing a complex and critical module of an AD framework, and provides some guidelines and practical evidence on how resource usage testing can be effectively performed, thus enabling end users to validate their safety-related real-time AD frameworks.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under grant TIN2015-65316-P, the UP2DATE European Union’s Horizon 2020 (H2020) research and innovation programme under grant agreement No 871465, and the HiPEAC Network of Excellence. MINECO partially supported Jaume Abella under Ramon y Cajal postdoctoral fellowship (RYC-2013-14717) and Leonidas Kosmidis under Juan de la Cierva-Formación postdoctoral fellowship (FJCI-2017-34095)Peer ReviewedPostprint (author's final draft
Effect of pregnancy planning and fertility treatment on cognitive outcomes in children at ages 3 and 5: longitudinal cohort study
Objective To investigate how pregnancy planning, time to conception, and infertility treatment influence cognitive development at ages 3 and 5
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Ethnic and socioeconomic variation in cause-specific preterm infant mortality by gestational age at birth: national cohort study
Objective: To describe ethnic and socioeconomic variation in cause-specific infant mortality of preterm babies by gestational age at birth.
Design: National birth cohort study.
Setting: England and Wales 2006–2012.
Subjects: Singleton live births at 24–36 completed weeks’ gestation (n=256 142).
Outcome measures: Adjusted rate ratios for death in infancy by cause (three groups), within categories of gestational age at birth (24–27, 28–31, 32–36 weeks), by baby’s ethnicity (nine groups) or area deprivation score (Index of Multiple Deprivation quintiles).
Results: Among 24–27 week births (5% of subjects; 47% of those who died in infancy), all minority ethnic groups had lower risk of immaturity-related death than White British, the lowest rate ratios being 0.63 (95% CI 0.49 to 0.80) for Black Caribbean, 0.74 (0.64 to 0.85) for Black African and 0.75 (0.60 to 0.94) for Indian. Among 32–36 week births, all minority groups had higher risk of death from congenital anomalies than White British, the highest rate ratios being 4.50 (3.78 to 5.37) for Pakistani, 2.89 (2.10 to 3.97) for Bangladeshi and 2.06 (1.59 to 2.68) for Black African; risks of death from congenital anomalies and combined rarer causes (infection, intrapartum conditions, SIDS and unclassified) increased with deprivation, the rate ratios comparing the most with the least deprived quintile being, respectively, 1.54 (1.22 to 1.93) and 2.05 (1.55 to 2.72). There was no evidence of socioeconomic variation in deaths from immaturity-related conditions.
Conclusions: Gestation-specific preterm infant mortality shows contrasting ethnic patterns of death from immaturity-related conditions in extremely-preterm babies, and congenital anomalies in moderate/late-preterm babies. Socioeconomic variation derives from congenital anomalies and rarer causes in moderate/late-preterm babies. Future research should examine biological origins of extremely preterm birth
Cognitive development following ART: effect of choice of comparison group, confounding and mediating factors
BACKGROUND: Epidemiological studies have examined the health of children born after assisted reproductive technology (ART), with contradictory results. In this article, we address the question 'Do singletons born after ART have a poorer cognitive developmental outcome at 3 years of age?' We assess the implications of using different comparison groups, and discuss appropriate analytical approaches for the control of confounding and mediating variables. METHODS: Data were drawn from the Millennium Cohort Study. Interviews captured sociodemographic, behavioural and pregnancy information. Developmental assessments conducted at age three included the British Ability Scales II Naming Vocabulary (BAS-NV) instrument. We compared ART infants (born after IVF or ICSI) to four comparison groups: a 'matched' group; a 'subfertile' group (time to conception >12 months); a 'fertile' group (time to conception <12 months); and an 'any spontaneous conceptions' group. Linear regression provided estimates of the difference in mean BAS-NV scores in the ART and comparison groups; both unadjusted estimates and those adjusted for confounding and mediating factors are presented. RESULTS: In the unadjusted analyses, ART children gained significantly better BAS-NV test results than did the comparison group children. When converted to an estimate of developmental age gap, ART children were 2.5, 2.7, 3.6 and 4.5 months ahead of the 'matched', 'subfertile', 'fertile' and 'spontaneous conception' children, respectively. After adjusting for confounding and mediating factors, the differences were reduced, and were not statistically significant. CONCLUSIONS: ART is not associated with poorer cognitive development at 3 years. We have highlighted methodological considerations for researchers planning to study the effect of infertility and ART on childhood outcomes
The contribution of gestational age, area deprivation and mother's country of birth to ethnic variations in infant mortality in England and Wales: A national cohort study using routinely collected data
OBJECTIVES: We aimed to describe ethnic variations in infant mortality and explore the contribution of area deprivation, mother's country of birth, and prematurity to these variations.
METHODS: We analyzed routine birth and death data on singleton live births (gestational age≥22 weeks) in England and Wales, 2006-2012. Infant mortality by ethnic group was analyzed using logistic regression with adjustment for sociodemographic characteristics and gestational age.
RESULTS: In the 4,634,932 births analyzed, crude infant mortality rates were higher in Pakistani, Black Caribbean, Black African, and Bangladeshi infants (6.92, 6.00, 5.17 and 4.40 per 1,000 live births, respectively vs. 2.87 in White British infants). Adjustment for maternal sociodemographic characteristics changed the results little. Further adjustment for gestational age strongly attenuated the risk in Black Caribbean (OR 1.02, 95% CI 0.89-1.17) and Black African infants (1.17, 1.06-1.29) but not in Pakistani (2.32, 2.15-2.50), Bangladeshi (1.47, 1.28-1.69), and Indian infants (1.24, 1.11-1.38). Ethnic variations in infant mortality differed significantly between term and preterm infants. At term, South Asian groups had higher risks which cannot be explained by sociodemographic characteristics. In preterm infants, adjustment for degree of prematurity (<28, 28-31, 32-33, 34-36 weeks) fully explained increased risks in Black but not Pakistani and Bangladeshi infants. Sensitivity analyses with further adjustment for small for gestational age, or excluding deaths due to congenital anomalies did not fully explain the excess risk in South Asian groups.
CONCLUSIONS: Higher infant mortality in South Asian and Black infants does not appear to be explained by sociodemographic characteristics. Higher proportions of very premature infants appear to explain increased risks in Black infants but not in South Asian groups. Strategies targeting the prevention and management of preterm birth in Black groups and suboptimal birthweight and modifiable risk factors for congenital anomalies in South Asian groups might help reduce ethnic inequalities in infant mortality
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Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study.
Purpose:To quantify peripapillary choroidal thickness (PCT) and the factors that influence it in healthy participants who represent the racial and ethnic composition of the U.S. population. Methods:A total of 362 healthy participants underwent optical coherence tomography (OCT) enhanced depth imaging of the optic nerve head with a 24 radial B-scan pattern aligned to the fovea to Bruch's membrane opening axis. Bruch's membrane, anterior scleral canal opening (ASCO), and the anterior scleral surface were manually segmented. PCT was measured at 100, 300, 500, 700, 900, and 1100 μm from the ASCO globally and within 12 clock-hour sectors. The effects of age, axial length, intraocular pressure, ethnicity, sex, sector, and ASCO area on PCT were assessed by ANOVA and univariable and multivariable regressions. Results:Globally, PCT was thicker further from the ASCO border and thinner with older age, longer axial length, larger ASCO area, European descent, and female sex. Among these effectors, age and axial length explained the greatest proportion of variance. The rate of age-related decline increased further from the ASCO border. Sectorally, the inferior-temporal sectors were thinnest (10.7%-20.0% thinner than the thickest sector) and demonstrated a higher rate of age-related loss (from 15.6% to 20.7% faster) at each ASCO distance. Conclusions:In healthy eyes, PCT was thinnest in the inferior temporal sectors and thinner PCT was associated with older age, European descent, longer axial length, larger ASCO area, and female sex. Among these associations, age had the strongest influence, and its effect was greatest within the inferior temporal sectors
Light drinking in pregnancy, a risk for behavioural problems and cognitive deficits at 3 years of age?
Background
The objective of this study was to determine whether there was an association between mothers’ light drinking during pregnancy and risk of behavioural problems, and cognitive deficits in their children at age 3 years.
Methods
Data from the first two sweeps of the nationally representative prospective UK Millennium Cohort study were used. Drinking patterns during pregnancy and behavioural and cognitive outcomes were assessed during interviews and home visits. Behavioural problems were indicated by scores falling above defined clinically 15 relevant cut-offs on the parent-report version of the Strengths and
Difficulties Questionnaire (SDQ). Cognitive ability was assessed using the naming vocabulary subscale from the British Ability Scale (BAS) and the Bracken School Readiness Assessment (BSRA).
Results
There was a J-shaped relationship between mothers drinking
20 during pregnancy and the likelihood of high scores (above the cut-off) on the total difficulties scale of the SDQ and the conduct problems, hyperactivity and emotional symptom SDQ subscales. Children born to light drinkers were less likely to score above the cut-offs compared with children of abstinent mothers. Children 25 born to heavy drinkers were more likely to score above the cut-offs
compared with children of abstinent mothers. Boys born to mothers who had up to 1–2 drinks per week or per occasion were less likely to have conduct problems (OR 0.59, 95% CI 0.45–0.77) and hyperactivity (OR 0.71, 95% CI 0.54–0.94). These effects remained 30 in fully adjusted models. Girls were less likely to have emotional symptoms (OR 0.72, 95% CI 0.51–1.01) and peer problems (OR 0.68, 95% CI 0.52–0.92) compared with those born to abstainers. These effects were attenuated in fully adjusted models. Boys born to light drinkers had higher cognitive ability test scores [standard
35 deviations, (95% CI)] BAS 0.15 (0.08–0.23) BSRA 0.24 (0.16–0.32) compared with boys born to abstainers. The difference for BAS was attenuated on adjustment for socio-economic factors, whilst the difference for BSRA remained statistically significant.
Conclusions
Children born to mothers who drank up to 1–2 drinks per week or per occasion during pregnancy were not at increased risk of clinically relevant behavioural difficulties or cognitive deficits compared with children of abstinent mothers. Heavy drinking 5 during pregnancy appears to be associated with behavioural problems and cognitive deficits in offspring at age 3 years whereas light drinking does not
Noncovalent Interactions by QMC: Speedup by One-Particle Basis-Set Size Reduction
While it is empirically accepted that the fixed-node diffusion Monte-Carlo
(FN-DMC) depends only weakly on the size of the one-particle basis sets used to
expand its guiding functions, limits of this observation are not settled yet.
Our recent work indicates that under the FN error cancellation conditions,
augmented triple zeta basis sets are sufficient to achieve a benchmark level of
0.1 kcal/mol in a number of small noncovalent complexes. Here we report on a
possibility of truncation of the one-particle basis sets used in FN-DMC guiding
functions that has no visible effect on the accuracy of the production FN-DMC
energy differences. The proposed scheme leads to no significant increase in the
local energy variance, indicating that the total CPU cost of large-scale
benchmark noncovalent interaction energy FN-DMC calculations may be reduced.Comment: ACS book chapter, accepte
Application of Correct-by-Construction Principles for a Resilient Risk-Aware Architecture
In this paper we discuss the application of correct-by-construction techniques to a resilient,
risk-aware software architecture for onboard, real-time autonomous operations. We
mean to combat complexity and the accidental introduction of bugs through the use of
verifiable auto-coding software and correct-by-construction techniques, and discuss the use
of a toolbox for correct-by-construction Temporal Logic Planning (TuLiP) for such a purpose.
We describe some of TuLiP’s current functionality, specifically its ability to model
symbolic discrete systems and synthesize software controllers and control policies that are
correct-by-construction. We then move on to discuss the use of these techniques to define a
deliberative goal-directed executive capability that performs risk-informed action-planning
– to satisfy the mission goals (specified by mission control) within the specified priorities
and constraints. Finally, we discuss an application of the TuLiP process to a simple rover
resilience scenario
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