Differences in the relationship of weight to height, and thus the meaning of BMI, according to age, sex, and birth year cohort.

Background: Weight can be adjusted for height using the Benn parameter (kg/mB), where B is the power that minimises the correlation with height.Aim: To investigate how the Benn parameter changes across age (10-65 years) and time (1956-2015) and differs between sexes.Subjects and methods: The sample comprised 49,717 individuals born in 1946, 1958, 1970 or 2001. Cross-sectional estimates of the Benn parameter were produced and cohort differences at ages 10/11 and 42/43 years were examined using linear regression. Multilevel modelling was used to develop trajectories showing how the Benn parameter changed over age from childhood to mid-adulthood in the three older cohorts.Results: The Benn parameter was closest to 2 in childhood but consistently lower across adulthood, particularly in females and the most recent cohort. At ages 10/11 years, the Benn parameter was greater than 3 in both sexes in the 2001 cohort but between 2.2 and 2.7 in the three older cohorts. This difference was estimated to be +0.67 (0.53, 0.81) in males and +0.53 (0.38, 0.68) in females, compared to the 1946 cohort, and was driven by a much higher weight SD in the 2001 cohort. Conversely, at ages 42/43 years, the Benn parameter was lowest in the 1970 cohort due to a slightly lower weight-height correlation. This difference was estimated to be -0.12 (-0.34, 0.10) in males and -0.15 (-0.42, 0.13) in females, compared to the 1946 cohort.Conclusions: Changes over time in the obesogenic environment appear to have firstly reduced the Benn parameter due to a lowering of the weight-height correlation but secondly and more drastically increased the Benn parameter due to increasing weight variation.

Fortified complementary foods with or without alpha-amylase treatment increase hemoglobin but do not reduce breast milk intake of 9-mo-old Zambian infants.

BACKGROUND: Malnutrition in late infancy in developing countries may result from poor-quality complementary foods that displace breast milk. OBJECTIVE: The objective of the study was to assess the effects of fortified complementary blends of different energy densities on growth, hemoglobin concentrations, and breast milk intake of 9-mo-old Zambian infants. DESIGN: Infants were randomly assigned at 6 mo of age to receive for 3 mo a fortified blend of maize, beans, bambaranuts, and groundnuts [Chilenje Baby Mix (CBM); energy density: 68 kcal/100 g; n = 37] or a similar blend with alpha-amylase (CBMA; energy density: 106 kcal/100 g; n = 44). Cross-sectional data were obtained at 9 mo for a control group of infants (n = 69) not given the diets. Breast milk intake was measured by using the dose-to-the-mother deuterium dilution technique. RESULTS: No differences in weight or length z scores, all of which were within normal ranges, were seen between groups at 9 mo. Percentage fat mass was significantly (P = 0.01) greater in the infants in both the CBM (23.2 +/- 2.7%) and CBMA (23.4 +/- 2.5%) groups than in the control group (21.6 +/- 2.6%). Hemoglobin concentrations were significantly (P = 0.03) greater in both intervention groups (CBM group: 104 +/- 12 g/L: CBMA group: 103 +/- 12 g/L) than in the control group (98 +/- 14 g/L). Breast milk intake was not significantly (P = 0.87) different between groups (CBM group: 614 +/- 271 g/d; CBMA group: 635 +/- 193 g/d; control group: 653 +/- 221 g/d). CONCLUSIONS: The study foods improved hemoglobin concentrations without reducing breast milk intake and may be used to improve the nutritional status of infants in developing countries.

Design and construction of an Electric Fish Finder

We provide notes on the design and construction of an Electric Fish Finder - a portable differential amplifier for detecting the electrostatic fields of gymnotiform knifefishes. The device can be adapted to locate electric fishes in any kind of aquatic environment. It is rugged, water resistant, and powered by alkaline batteries. This contribution is part of a series of technical papers designed to encourage students of neotropical ichthyology to explore the ecology, systematics, and electric signaling of gymnotiform fishes

Nós fornecemos o esquema e as instruções para a construção de um Detector de Peixes Elétricos - um amplificador portátil de banda larga utilizado para detectar os campos elétricos de peixes gymnotiformes. Este aparelho pode ser adaptado para encontrar peixes elétricos em diversos ambientes aquáticos. É resistente, à prova d'água e energizado por baterias alcalinas. Esta contribuição faz parte de uma série de artigos técnicos que pretende encorajar estudantes de ictiologia neotropical a explorar a ecologia, sistemática e comunicação elétrica de peixes gymnotiformes