Ellipse-preserving Hermite interpolation and subdivision

We introduce a family of piecewise-exponential functions that have the Hermite interpolation property. Our design is motivated by the search for an effective scheme for the joint interpolation of points and associated tangents on a curve with the ability to perfectly reproduce ellipses. We prove that the proposed Hermite functions form a Riesz basis and that they reproduce prescribed exponential polynomials. We present a method based on Green's functions to unravel their multi-resolution and approximation-theoretic properties. Finally, we derive the corresponding vector and scalar subdivision schemes, which lend themselves to a fast implementation. The proposed vector scheme is interpolatory and level-dependent, but its asymptotic behaviour is the same as the classical cubic Hermite spline algorithm. The same convergence properties---i.e., fourth order of approximation---are hence ensured

Reproductive factors and incidence of breast cancer: An international ecological study

Summary: Ecological studies can help in understanding the relation of reproductive history to breast cancer. We analyzed data from 9416 women, comprising the control groups of seven countries (Australia, People's Republic of China, Colombia, (former) German Democratic Republic, Israel, Philippines, and Thailand) from the WHO international, multi-center case-control study of female cancers. Positive correlations with country-specific breast cancer incidence were observed for (median) duration of reproductive life (r≥0.95, p<0.005), age at menopause (r≥0.84, p<0.025) and delay to first birth (r≥0.59, p<0.22) (when People's Republic of China was omitted, r≥0.85, p<0.07). The association of age at first birth with breast cancer incidence was weakly positive in the whole sample (age-adjusted r=0.18, p=0.73), but weakly negative in the age groups 15-29 and 30-39 years and weakly positive in the age groups 40-49 and 50-64 years. A strong inverse correlation was observed between age at menarche and breast cancer incidence (r≤−0.84, p<0.03). These international ecological correlations agree with the associations previously reported for single populations, between higher incidence of breast cancer and younger age at menarche, older age at menopause, longer duration of reproductive life, and (possibly) longer delay to first birth. In contrast, age at first birth is only weakly related to breast cancer incidence across populations, indicating that this variable represents different constructs when measured ecologically versus individuall

The Xeros data model: tracking interpretations of archaeological finds

At an archaeological dig, interpretations are built around discovered artifacts based on measurements and informed intuition. These interpretations are semi-structured and organic, yet existing tools do not capture their creation or evolution. Patina of Notes (PoN) is an application designed to tackle this, and is underpinned by the Xeros data model. Xeros is a graph structure and a set of operations that can deal with the addition, edition, and removal of interpretations. This data model is a specialisation of the W3C PROV provenance data model, tracking the evolution of interpretations. The model is presented, with operations defined formally, and characteristics of the representation that are beneficial to implementations are discussed

Come on, Come on, Do the Loco-Motion

This themed issue of Preventive Medicine comprises articles following our call for papers on Self-Transportation, Public Transportation, and Health. Prevention-wise, the logic is that using self- or public transportation is likely to increase physical activity and counter the overall trend toward obesity that most populations of the world are now experiencing. The problem is that in countries for which data are available, both the cycling fraction of road traffic and the number of miles walked are declining (Dora, 1999; Haines et al., 2000). The harvest of papers has been rewarding. They show how far we currently are in the process of assembling evidence in support of the self/public transportation and health connection, but they also reflect the deficits in the experimental evidence needed to demonstrate that improving access to public transportation and modifying the built environment to stimulate walking and biking are going to make a meaningful difference in terms of public health

International Variability in Ages at Menarche, First Livebirth, and Menopause

The occurrences and timing of reproduction-related events, such as menarche, first birth, and menopause, play major roles in a woman's life. There is a lack of comparative information on the overall patterns of the ages at and the timing between these events among different populations of the world. This study describes the variability in reproductive factors across populations in Europe, the Americas, Asia, Australia, and Africa. The study sample consisted of 18,997 women from 13 centers in 11 countries interviewed between 1979 and 1988 who comprised the control group in a World Health Organization international, multicenter case-control study of female cancers. All were surveyed with the same questionnaire and methodology. Overall, a typical woman in this study reached menarche at age 14 years and delivered her first live child 8 years later, at age 22. She was 50 years old at natural menopause and had had 36 years of reproductive life. The median ages at menarche varied across centers from 13 to 16 years. For all centers, the median age at first livebirth was 20 or more years, with the largest observed median (25 years) occurring in China. The median delay from menarche to first livebirth ranged from 5 to 11 years. Among the centers, the median age at natural menopause ranged between 49 and 52 years. In most populations, younger women had a first birth at a later age than did older women. This tendency was more accentuated in some populations. These results reveal, perhaps for the first time, the variability of reproductive histories across different populations in a large variety of geographic and cultural settings. Except for menopause, international variability is substantial for both biologically related variables (age at menarche) and culturally related variables (age at first birth). There is a generational effect, characterized by more variability of age at first birth and delay to first birth in the younger than in the older generations. Am J Epidemiol 1998;148:1195-120

Physical activity of urban adults: A general population survey in Geneva

Summary: Objectives: Describing the distribution of physical activity in populations is of major importance for developing public health campaigns to prevent sedentarism. Methods: A population-based survey conducted during 1997-1999 in Geneva, Switzerland, included 3410 randomly selected men (n=1707) and women (n=1703), aged 35 to 74 years. Percentiles P10, P50, and P90 summarised the distributions of the total energy expenditure and of the percents used in moderate intensity activities (3 to 3.9 times the basal metabolism rate (BMR), e.g., normal walking, household chores), and in high and very high intensity activities (≥ 4 BMR, e.g., brisk walking, sports). Results: The total energy expenditure (median 2929 kcal/day in men, 2212 kcal/day in women) decreased with age. Prevalence of sedentarism, defined as less than 10% of total energy expended in ≥4 BMR activities, was 57% in men and 70% in women. Men expended 12% (median) of their total energy in 3 to 3.9 BMR and 8% in ≥4 BMR activities. Corresponding percentages in women were 11% and 5%. The highest prevalence of sedentarism was in older age, women, and lower socio-economic status persons. Conclusion: Most of Geneva population is sedentary. Promoting physical activity should target children, adults and elderly, and physical activity should target children, adults and elderly, and physical activities which would be both attractive and financially affordable by most peopl

Experimental approach to measuring functional food consumption for risk factor surveillance

Abstract Objective To develop and integrate the assessment of functional foods (FuF; manufactured foods with altered composition carrying a health claim) consumption into an existing risk factor surveillance system. Design FuF market research followed by an experimental FuF intake study incorporated into an ongoing community-based survey. Concurrent completion of a self-administered semi-quantitative FFQ and a self-administered, qualitative FuF frequency questionnaire (FuFFQ) followed by a face-to-face control step using FuF photographs and combined food group-based data analyses. Setting ‘Bus Santé' risk factor surveillance programme, Geneva/Switzerland. Subjects Population-based random sample of 639 residents (52 % women, aged 35-74 years) surveyed from September 2003 to April 2004. Results Local Geneva/French neighbourhood market research identified 148 FuF in five major FuF food groups which were compiled into a functional ingredient database. Prior to the face-to-face verification, 210 (33 %) individuals categorized themselves as FuF consumers, 429 (67 %) as non-consumers. The control step revealed that 70 % of the 639 participants were already familiar with the FuF concept, and thus were correctly self-categorized as FuF consumers or non-consumers. For the remaining 30 % of participants the true FuF consumption status was established, resulting in a final number of 285 FuF consumers (45 %; 12 % net increase) and 354 (55 %) non-consumers. Conclusions The developed self-administered, brief, qualitative food group-based FuF frequency check list in combination with an FFQ and a photo-assisted control step provides a flexible assessment tool for measuring FuF consumption in the context of a specific fluctuating FuF market and may be applicable to other population settings and time

'A bit like British Weather, I suppose' Design and Evaluation of the Temperature Calendar

In this paper we present the design and evaluation of the Temperature Calendar -- a visualisation of temperature variation within a workplace over the course of the past week, highlights deviation from organisational temperature policy, and aims to bring staff "into the loop" of understanding and managing heating, and so reduce energy waste. The display was deployed in five public libraries. Analysis of logs, questionnaires and interviews shows staff used the displays to understand heating in their buildings, and took action to relate their libraries to organisational policy and improve thermal comfort. We also present a subsequent lab study, demonstrating that adding electricity consumption to the visualisation did not improve likelihood of spotting heating "errors". Bringing together our results, we discuss three topics of relevance to the research community: design implications for workplace displays, the engagement of staff through focus on organisational policy, and sustainability cost-benefit analysis of the Temperature Calendar