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Students learn by repetition. Repetition is essential, but repetition needs questioning, and questioning the repertoire belongs to the essential tasks of student education. Guiding students to questioning was and is our prime motive to offer our International Student Summer Schools. The data were critically discussed among the students, in the twilight of Just So Stories, common knowledge, and prompted questioning of contemporary solutions. For these schools, the students bring their own data, carry their preliminary concepts, and in group discussions, they may have to challenge these concepts. Catch-up growth is known to affect long bone growth, but different opinions exist to what extent it also affects body proportions. Skeletal age and dental development are considered appropriate measures of maturation, but it appears that both system develop independently and are regulated by different mechanisms. Body weight distributions are assumed to be skewed, yet, historic data disproved this assumption. Many discussions focused on current ideas of global growth standards as a common yardstick for all populations world-wide, with new statistical tools being developed including network reconstruction and evaluation of the reconstructs to determine the confidence of graph prediction methods.
Modeling a secular trend by Monte Carlo simulation of height biased migration in a spatial network
(2017)
Background: In a recent Monte Carlo simulation, the clustering of body height of Swiss military conscripts within a spatial network with characteristic features of the natural Swiss geography was investigated. In this study I examined the effect of migration of tall individuals into network hubs on the dynamics of body height within the whole spatial network. The aim of this study was to simulate height trends. Material and methods: Three networks were used for modeling, a regular rectangular fishing net like network, a real world example based on the geographic map of Switzerland, and a random network. All networks contained between 144 and 148 districts and between 265-307 road connections. Around 100,000 agents were initially released with average height of 170 cm, and height standard deviation of 6.5 cm. The simulation was started with the a priori assumption that height variation within a district is limited and also depends on height of neighboring districts (community effect on height). In addition to a neighborhood influence factor, which simulates a community effect, body height dependent migration of conscripts between adjacent districts in each Monte Carlo simulation was used to re-calculate next generation body heights. In order to determine the direction of migration for taller individuals, various centrality measures for the evaluation of district importance within the spatial network were applied. Taller individuals were favored to migrate more into network hubs, backward migration using the same number of individuals was random, not biased towards body height. Network hubs were defined by the importance of a district within the spatial network. The importance of a district was evaluated by various centrality measures. In the null model there were no road connections, height information could not be delivered between the districts. Results: Due to the favored migration of tall individuals into network hubs, average body height of the hubs, and later, of the whole network increased by up to 0.1 cm per iteration depending on the network model. The general increase in height within the network depended on connectedness and on the amount of height information that was exchanged between neighboring districts. If higher amounts of neighborhood height information were exchanged, the general increase in height within the network was large (strong secular trend). The trend in the homogeneous fishnet like network was lowest, the trend in the random network was highest. Yet, some network properties, such as the heteroscedasticity and autocorrelations of the migration simulation models differed greatly from the natural features observed in Swiss military conscript networks. Autocorrelations of district heights for instance, were much higher in the migration models. Conclusion: This study confirmed that secular height trends can be modeled by preferred migration of tall individuals into network hubs. However, basic network properties of the migration simulation models differed greatly from the natural features observed in Swiss military conscripts. Similar network-based data from other countries should be explored to better investigate height trends with Monte Carlo migration approach.
The aim of the study was to investigate the correlation of heights of conscripts living in neighboring districts in Poland. The study used 10% of a nationally representative sample of 26,178 males 18.5-19.5 years old examined during the National survey of Polish conscripts conducted in 2001. The sample represented all regions and social strata of the country and included 354 different districts within 16 voivodships (provinces). Analyses were performed with the R statistical software. A small but significant correlation (0.24, p < 0.0001) was observed for height between 1st order neighboring districts. Correlations decreased with increased distances between neighboring districts, but remained significant for 7th node neighbors (0.18, p < 0.0001). Regarding voivodships (provinces), average height showed a geographical trend from the northwest (relatively tall) to the southeast (relatively short), and the correlation was stronger for first order neighboring provinces (0.796, p < 0.001). This study revealed clusters of tall people and short people, providing a support for hypothesis of the community effect in height. Small correlations between 1st order neighbors than in another country (Switzerland) may be associated with differences in geography, since in Poland there are no natural barriers (e.g., mountains) and road infrastructure is well-developed.
Background: We investigated height of Norwegian conscripts in view of the hypothesis of a "community effect on height" using autocorrelation analysis of district heights within a time-span of 20 years at the end of the 19th century and correlations between neighboring districts at this time. Material and methods: After digitalizing available body height data of Norwegian draftees in 1877-1878, 1880 (averaged as 1878), and 1895-1897 (averaged as 1896) we calculated the magnitude of autocorrelation of body height within the same municipality at different time points. Furthermore, we generated three different neighborhood networks, (1) based on Euclidean distances, (2) a minimum spanning tree build on those distances, (3) a network founded on real world road connections. The networks were used to determine the correlation between body height of neighboring districts depending on the number of edges required to connect two municipalities. Results: The autocorrelation value for body heights was around r = 0.5 (for all p < 0.001) in the years 1878 and 1896. The correlation between neighboring districts varied in the Euclidean distance based network between 0.47 and 0.27 approximately for both years in a sorted order, descending from nearest (0-50 km) to farthest (150-200 km, for all p < 0.001). First order neighbors in the minimum spanning tree network correlation was 0.36 in 1878 and 0.42 in 1896 (for all p < 0.001). The values of neighbor correlation in the road connection based network ranged in 1878 from 0.42 (first order neighbors) to 0.17 (forth order neighbors, for all p < 0.01) and in 1896 from 0.46 (first order neighbors) to 0.12 (forth order neighbors, for all p < 0.05). Conclusion: This initial study of Norwegian conscript height data from the 19th century showed significant medium sized effects for the within district autocorrelation between 1878 and 1896 as well as medium neighborhood correlation, slightly lower in comparison to a recent study regarding Swiss conscripts. Digitalizing more data from other years in this and later time spans as well as using older road and ship connections instead of the actual road data might stabilize and improve those findings.
Aim: We aimed to examine the distribution and secular changes of conscript body height in the geographic network of Norway since 1878 and to study its association with the degree of urbanization, and population density. Material and methods: Data on body height of Norwegian military conscripts were provided by the Statistics Norway Department (SSB). The sample comprised eight cohorts with the following measurement years: 1st 1877, 1878 and 1880, 2nd 18951897, 3rd 1915-1917, 4th 1935-1937, 5th 1955-1957, 6th 1975-1977, 7th 1995-1997, and 8th 2009-2011. For determining neighborhood correlations, a network was created consisting of neighboring counties, sharing a common border. Results: Average body height of Norwegian men increased by 10.9 cm between 1878 and 2010, but this trend was heterogeneous. Some counties increased by more than 1 cm per decade (Finmark) others by only 7 mm per decade (Sor-Trondelag). Urban counties and counties with higher population density showed stronger height trends than rural counties. The largest spread in body height between the various counties was observed in 1936 when for the first time people living in the more urban counties got taller than rural people. The height advantage of urban counties however, disappeared after 1996. At this time, also the secular trend in height had come to a halt. The secular trend in height had become obvious after the dissolution of the union between Norway and Sweden in 1905 and World War I, and was strongest between 1936 and 1956. During this period maximum between-county heterogeneity in height existed with body height differences of more than 6 cm between the tallest and the shortest county. The end of this period was characterized by social democratic reforms that flattened the income distribution, eliminated poverty, and ensured social services after World War II. Conclusion: The temporal coincidence between the trends in height, the degree of urbanization and the onset of the political transition of Norway from a Swedish province into an independent democratic wealthy modern European state after World War I and particularly after World War II, and the abatement of this trend after this period of transition had stabilized, suggest social and political components interfering with the regulation of physical growth in humans.
Eighteen scientists met at Jurata, Poland, to discuss various aspects of the transition from adolescence to adulthood. This transition is a delicate period facing complex interactions between the adolescents and the social group they belong to. Social identity, group identification and identity signalling, but also stress affecting basal salivary cortisol rhythms, hypertension, inappropriate nutrition causing latent and manifest obesity, moreover, in developing and under-developed countries, parasitosis causing anaemia thereby impairing growth and development, are issues to be dealt with during this period of the human development. In addition, some new aspects of the association between weight, height and head circumference in the newborns were discussed, as well as intrauterine head growth and head circumference as health risk indicators.
The Western honey bee (Apis mellifera) is widely used as commercial pollinator in worldwide agriculture and, therefore, plays an important role in global food security. Among the parasites and pathogens threatening health and survival of honey bees are two species of microsporidia, Nosema apis and Nosema ceranae. Nosema ceranae is considered an emerging pathogen of the Western honey bee. Reports on the spread of N. ceranae suggested that this presumably highly virulent species is replacing its more benign congener N. apis in the global A. mellifera population. We here present a 12 year longitudinal cohort study on the prevalence of N. apis and N. ceranae in Northeast Germany. Between 2005 and 2016, a cohort of about 230 honey bee colonies originating from 23 apiaries was sampled twice a year (spring and autumn) resulting in a total of 5,600 bee samples which were subjected to microscopic and molecular analysis for determining the presence of infections with N. apis or/and N. ceranae. Throughout the entire study period, both N. apis- and N. ceranae-infections could be diagnosed within the cohort. Logistic regression analysis of the prevalence data demonstrated a significant increase of N. ceranae-infections over the last 12 years, both in autumn (reflecting the development during the summer) and in spring (reflecting the development over winter) samples. Cell culture experiments confirmed that N. ceranae has a higher proliferative potential than N. apis at 27. and 33 degrees C potentially explaining the increase in N. ceranae prevalence during summer. In autumn, characterized by generally low infection prevalence, this increase was accompanied by a significant decrease in N. apis- infection prevalence. In contrast, in spring, the season with a higher prevalence of infection, no significant decrease of N. apis infections despite a significant increase in N. ceranae infections could be observed. Therefore, our data do not support a general advantage of N. ceranae over N. apis and an overall replacement of N. apis by N. ceranae in the studied honey bee population.
Background: The association between stature and social dominance is known. Dominance within social groups and current politics are related issues. We therefore aimed to compare estimates of the opinion of a population about their current political issues, with physical growth. Material and methods: We used data on the 2012 and the 2014 elections for the Japanese House of Representatives and the percent proportion of votes of the 47 prefectures of Japan, and regional data on body height of 17.5 year old men and women. Information on capita income, possession of mobile phones, urban/rural population ratio, and age distribution were added to capture socioeconomic factors. Four political parties were present in most of the 47 prefectures: the Liberal Democratic Party (LDP), the Democratic Party of Japan (DPJ), the New Komeito Party (Kom) that is known for their social network community, and the Japanese Communist Party (JCP). Results: A dense network of associations exists between height, age distribution, per capita income, number of smartphones, and voting results. Male and female body height was inversely related with the proportion of votes for New Komeito Party. Average stature decreases by one mm per percent votes for this political party. Medium strong positive associations were found for male body height and voting results of the DPJ and for female body height with the JCP election results. Conclusion: In modern Japan, popular preferences for conservative political structures coincide with shorter stature.
Introduction: Body height is influenced by biological factors such as genetics, nutrition and health, but also by the social network, and environmental and economical factors. During centuries, the Japanese society has developed on islands. This setting provides ideal natural conditions for studying the influence of social networks on human height. Material and methods: We investigated body height of male Japanese students aged 17.5 years obtained in 47 prefectures, from the Japanese school health survey of the years 1955, 1975, 1995, and 2015. Results: Japanese students increased in height from 163.23 cm in 1955 to 170.84 cm in 1995, with no further increase thereafter (170.63 cm in 2015). Students living in neighboring prefectures were similar in height. The correlation of height between neighboring prefectures ranged between r = 0.79 and r = 0.49 among first degree neighbors, between r = 0.49 and r = 0.21 among second degree neighbors and dropped to insignificance among third degree neighbors indicating psychosocial effects of the community on body height. Tall stature and short stature prefectures did not remain tall or short throughout history. Autocorrelations of height within the same prefectures decreased from the 20 years periods of 1955-1975, 1975-1995 and 1995-2015 (r = 0.52, r = 0.61, r = 0.63, respectively) to the 40 years periods of 1955-1995 and 1975-2015 (r = 0.49, r = 0.52), down to the 60 years period of 1955-2015 (r = 0.27), indicating significant volatility of height. Conclusion: Body height of 17.5 years old Japanese students increased since 1955. Body height depended on height of the neighboring prefecture, but was volatile with decreasing autocorrelation during a period of 60 years.