Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?

We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68REarth) and Kepler-10b (∼1.416REarth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a "Hot Neptune" nor a "Hot Uranus"-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects.

BMI values and other anthropometric and functional measurements as predictors of obesity in a selected group of adolescents.

BACKGROUND: Obesity is well known to be a problem all over the world: WHO data report that one billion subjects are overweight and 300 million are obese. Epidemiological data (IOTF) show that prevalence rates are increasing not only in industrialized countries, but also in developing countries, especially as far as the adolescent population is concerned. AIM OF THE STUDY: To select adolescents at risk of obesity by BMI calculation and by other anthropometric and functional measurements in the Aosta Valley Mountain Region (Northern Italy). METHODS: 532 adolescents were recruited and participated in the study (254 males and 278 females, aged 15.4 +/- 0.7). According to standard methods, the following parameters were measured: weight and height for BMI calculation, four skin folds (mid-triceps,mid-biceps, subscapular and supra-iliac) to compute body fat mass,waist and hip circumferences, systolic (SBP) and diastolic (DBP) blood pressure. Parental weight and height, educational and socio-economic status were requested from the parents using a questionnaire. RESULTS: Percentages of overweight and obese boys were 20.9% and 4.7% respectively, and percentages of overweight and obese girls were 14.7% and 1.1% respectively (using Cole's cut off point reference standard). Mean body fat mass percentages (males = 19.3 +/- 5.6%, females 23.3 +/- 4.4%) showed males at risk of obesity, as indicated by a higher prevalence rate of overweight and obesity in this gender. Positive correlations (p <0.01) were found between BMI and the following parameters: mid-triceps skinfolds, body fat mass percentage,waist and hip circumferences, but no correlation emerged with WHR; body fat mass positively correlates (p <0.01) with waist and hip circumferences; students' BMI positively correlates with blood pressure (p <0.01),with parental BMI and shows a positive trend towards parental low education and socioeconomic levels. CONCLUSIONS: Overweight and obesity prevalence rates are higher in males than in females according to literature data; family influences weight condition. The correlations that emerged show that BMI is a good adiposity index also in adolescents, it acts as an indicator of cardiovascular risk condition and is influenced by parental BMI.

An evaluation of a colour food photography atlas as a tool for quantifying food portion size in epidemiological dietary surveys.

OBJECTIVE: To test the validity of a colour food photography atlas for quantifying portion size eaten compared with weighed foods. DESIGN: The colour food photography atlas was prepared by cooking, weighing and taking digital photographs of three portion sizes of 434 foods and beverages typical of the Italian diet. SUBJECTS AND INTERVENTIONS: In all, 448 male and female volunteers aged 6-60 y from a wide variety of social backgrounds completed 9075 assessments of food portions eaten at lunch and dinner in relation to a set of colour food photographs during 8 weeks of investigation. The amounts of foods eaten by individuals in five different cafeterias in Pavia, Northern Italy, were weighed by trained investigators at the time of serving and, within 5-10 min of the end of the meal, each subject was asked to quantify all foods consumed with reference to one of the three food photographs or in terms of virtual portions among those shown in the photographs. RESULTS: Multiple regression analysis shows that weights of portion sizes chosen from the set of photographs are significantly associated (P<0.05) to weights of eaten portions (beta=0.81; R(2)=0.70) and are independent of age, gender and BMI. The differences between mean weights of the portions chosen by individuals from photographs and mean weights of eaten foods are significant for all food categories (P<0.05), except for bread. However, because of the very large number of observations, the mean differences are very small (range: from +23.2 g (+11.2%) for first courses to -1.3 g (-2.7%) for bread). Bland-Altman plots show that first courses limits of agreement are wide because the dispersion is increasing while weights are rising. CONCLUSIONS: The use of a series of three photographs and virtual portion sizes being associated with relatively small errors, our findings support the validity of using this colour food photography atlas as a tool for quantifying food portion size in epidemiological dietary surveys on different age groups of Italian subjects.

[Adolescent Body Mass Index data: what differences result using different reference standard curves?]. / Indice di Massa Corporea e adolescenti: quali le differenze utilizzando diversi standard di riferimento?

Childhood and adolescent obesity prevalence rates have steadily increased both in industrialised and developing countries in the last years. Data from literature show that BMI is an acceptable indicator to assess overweight and obesity also in children and adolescents. Different reference standard curves for BMI exist: the percentiles of Rolland-Chacherà, Luciano, the National Center for Health Statistics, Cole and Cacciari. Nevertheless, different cut off points are used by the authors to identify underweight, overweight and obesity. The aim of the present study was to investigate what differences can emerge when comparing adolescent BMI using different references standard curves. Five hundreds and thirty-five adolescent subjects, aged 15.4 +/- 0.7 years, were recruited in Aosta Valley (Northen Italy). BMI was calculated according to the following equation: BMI = weight/height2 (kg/m2). The data obtained were distributed according to BMI percentiles and than compared with references standard curves. The comparison shows different results especially when underweight, overweight and obesity are identified. In conclusion, it can be asserted that BMI is an useful indicator to assess adiposity (overweight and obesity) in adolescent, but one should be cautious when comparing results based on different references.