Shrinking in a growing economy is not so puzzling after all.

Bodenhorn, Guinnane, and Mroz (2017) argue that the diminution of heights during the Industrial Revolution and in the Antebellum U.S. is an artefact of the biased nature of the samples analyzed. We demonstrate that it would be an unfathomable coincidence if men and women all self-selected into scores of completely independent samples in such a way as to bias them in the identical direction. Instead, wWe show that BGM's periodization is flawed and that their statistical models are misspecified, because they fail to consider the extent to which they introduce severe multicollinearity into their regressions. In addition, they fail to specify how they selected the samples they included in their analysis. In contrast, we argue that the economic transition from a predominantly agricultural to an increasingly industrial society was not a smooth process and lags in adjustment led to nutritional stresses. Height of a typical man in the U.S. decreased by 0.75 inches at a time when incomes were growing at a rate of 1.2% per annum. The developing human body of children and youth was sensitive enough to these nutritional stresses to register their effect better than monetary measures could. While nutritional status did decline during the Industrial Revolution in Europe and at the onset of modern economic in the U.S., by the second half of the 19th century agricultural productivity caught up with the increased demand for foodstuffs and height reversals became a rarity. Thus, although markets adjusted, they did not do so instantaneously. Consequently, physical stature declined during this adjustment process although the wealthy were shielded from the increased price of nutrients. So, the divergence in average incomes and average heights at the threshold of the modern age is not so puzzling after all.

The BMI values of the lower classes likely declined during the Great Depression.

The BMI values of inmates in the McNeil Island Penitentiary in Washington State declined between the 1860s and the 1910s birth cohorts by 1.44. Furthermore, those who were imprisoned in the 1930s had significantly lower BMI values (by between 0.72 and 1.01) than those who were incarcerated at the end of the 19th century. This corresponds to a decrease in weight of some 2.25kg (4.95lbs) for a man of average height of 173.86cm (68.5inches). The diminution in nutritional status among this lower-class sample is hardly surprising, given the high level of unemployment at the time but has not been verified until now. In marked contrast, the BMI values of Citadel cadets increased by 1.5 units in the 1930s. This divergence in BMI values is most likely due to the different social status, to the different regional origins of the two samples or to both.

WITHDRAWN: European heights in the early 18th century.

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The trend of BMI values of US adults by deciles, birth cohorts 1882-1986 stratified by gender and ethnicity.

We estimate trends in BMI values by deciles of the US adult population by birth cohorts 1882-1986 stratified by ethnicity and gender. The highest decile increased by some 18-22 BMI units in the course of the century while the lowest ones increased by merely 1-3 BMI units. For example, a typical African American woman in the 10th percentile and 64 in. (162.6 cm) tall increased in weight by just 12 pounds (5 kg) whereas in the 90th percentile her weight would have increased by 128 pounds (58 kg). Hence, the BMI distribution became increasingly right skewed as the distance between the deciles increased considerably. The rate of change of the BMI decile curves varied greatly over time and across gender and ethnicity. The BMI deciles of white men and women experienced upswings after the two world wars and downswings during the Great Depression and also decelerated after 1970. However, among African Americans the pattern is different during the first half of the century with men's rate of increase in BMI values decreasing substantially and that of females remaining constant at a relatively high level until the Second World War. After the war, though, the rate of change of BMI values of blacks came to resemble that of whites with an accelerating phase followed by a slowdown around the 1970s.

The trend of mean BMI values of US adults, birth cohorts 1882-1986 indicates that the obesity epidemic began earlier than hitherto thought.

BACKGROUND: The trend in the body mass index (BMI) values of the US population has not been estimated accurately because the time series data are unavailable and the focus has been on calculating period effects. OBJECTIVES: To estimate the trend and rate of change of BMI values by birth cohorts stratified by gender and ethnicity born 1882-1986. METHODS: We use loess additive regression models to estimate age and trend effects of BMI values of US-born black and white adults measured between 1959 and 2006. We use all the National Health Examination Survey and National Health and Nutrition Examination Survey data. RESULTS: The increase in BMI was already underway among the birth cohorts of the early 20th century. The rate of increase was fastest among black females; for the three other groups under consideration, the rates of increase were similar. The generally persistent upward trend was punctuated by upsurges, particularly after each of the two world wars. The estimated rate of change of BMI values increased by 71% among black females between the birth cohorts 1955 and those of 1965 is indicative of the rapid increases in their weight. CONCLUSIONS: We infer that transition to postindustrial weights was a gradual process and began considerably earlier than hitherto supposed.

The recent decline in the height of African-American women.

Height trends since World War II are analyzed using the NHANES surveys for US-born individuals stratified by gender, ethnicity and income. After stagnating or declining for nearly a generation, the height of adult white men and women began to increase among the birth cohorts of ca. 1975-1986, who reached adulthood between 1995 and 2006. The increase in their height overcame the prior downturn that lasted between ca. 1965 and 1974. The height gap between white and black men has increased by 0.43cm (0.17in.) during past decade compared to the previous quarter century, to reach 1.0cm (0.39in.). In contrast to the three other groups examined, the height of black women has been actually declining by some 1.42cm (0.56in.). Consequently, a very considerable wedge has developed between black and white women's height of 1.95cm (0.77in.). In addition, black women in the age range 20-39 weigh some 9.5kg (21.0lb) more than their white counterparts. Two hypotheses are worth considering, namely, (a) that the decline in their height is related to the obesity epidemic and to inadequate dietary balance, and (b) that their future health will be subject to a double jeopardy in the sense that both their increasing weight and decreasing physical stature are likely associated with negative health consequences.

The transition to post-industrial BMI values among US children.

The trend in the BMI values of US children has not been estimated very convincingly because of the absence of longitudinal data. Our objective is to estimate time series of BMI values by birth cohorts instead of measurement years. We use five regression models to estimate the BMI trends of non-Hispanic US-born black and white children and adolescents ages 2-19 between 1941 and 2004. The increase in BMIZ values during the period considered was 1.3 sigma (95% CI: 1.16 sigma; 1.44 sigma) among black girls, 0.8 sigma for black boys, 0.7 sigma for white boys, and 0.6 sigma for white girls. This translates into an increase in BMI values of some 5.6, 3.3, 2.4, and 1.5 units, respectively. While the increase in BMI values started among the birth cohorts of the 1940s among black girls, the rate of increase tended to accelerate among all four ethnic/gender groups born in the mid-1950s to early-1960s. Some regional evidence leads to the conjecture that the spread of automobiles and radios affected the BMI values of boys already in the interwar period. We suppose that the changes in lifestyle associated with the labor saving technological developments of the 20th century are associated with the weight gains observed. The increased popularity of television viewing was most prominently associated with the contemporaneous acceleration in BMI gain.

Anthropometric history: an overview of a quarter century of research.

The systematic study of human physical stature reaches back into the 18th century. However, until French historians began to explore the socio-economic correlates of human height in the 1960s, the influence of the socio-economic environment primarily interested scholars of sister disciplines such as anthropology, auxology, or even military history. The present review summarizes a number of theoretical issues and new approaches to the understanding of the impact of economic processes on the human organism. Human organisms are sensitive to economic fluctuations and physical stature is an important complementary indicator, illuminating the extent to which a socio-economic or political system provides an environment--broadly conceived--propitious to the physical growth and longevity of human organisms.

Effect of sulfate on the simultaneous bioreduction of iron and uranium.

The biogeochemistry related to iron- and sulfate-reducing conditions influences the fate of contaminants such as petroleum hydrocarbons, trace metals, and radionuclides (i.e., uranium) released into the subsurface. An understanding of these processes is imperative to successfully predict the fate of contaminants during bioremediation scenarios. A series of flow-through sediment column experiments were performed to determine if the commencement of sulfate-reducing conditions would occur while bioavailable Fe(III) was present and to determine how the bioreduction of a contaminant (uranium) was affected by the switch from iron-dominated to sulfate-dominated reducing conditions. The results presented herein demonstrated that, under biostimulation, sulfate reduction can commence even though a significant pool of bioavailable Fe(III) is present. In addition, the rate of U(VI) reduction was not negatively affected by the commencement of sulfate-reducing conditions.

Differences in the physical growth of US-born black and white children and adolescents ages 2-19, born 1942-2002.

AIM: The present study estimates differences in the trend and in the age-by-height profiles of US-born non-Hispanic black and white children and adolescents born 1942-2002. SUBJECTS AND METHODS: The combined NHES and NHANES data sets stratified by ethnicity and gender were used. The differences in height-for-age z-scores (HAZ) were decomposed into an age effect and a secular trend effect using a non-linear regression model. RESULTS: The tempo of growth among blacks is faster than among whites. Black girls are more than 0.3sigma taller than white girls between the ages of 3 and 11. At age 9 this amounts to some 2.7 cm. White boys catch up to black boys at age 14 and white girls catch up at age 15 and are taller thereafter. At age 19 whites are only slightly taller: By 0.12sigma (0.8 cm) for boys and 0.03sigma (0.2 cm) among girls. The cumulative effect of the differences in the secular trend is considerable. Between the birth cohorts of the mid-1950s and the beginning of the new century blacks gained some 0.17sigma (girls) and 0.23sigma (boys) relative to white HAZ values. CONCLUSION: Blacks have a faster tempo of linear growth in childhood partly on account of their nutritional habits, as girls in particular tend to have higher BMI values, and partly probably because of genetic differences.

Height of US-born non-Hispanic children and adolescents ages 2-19, born 1942-2002 in the NHANES samples.

We examine the height of non-Hispanic US-born children born 1942-2002 on the basis of all NHES and NHANES data sets available. We use the CDC 2000 reference values to convert height into height-for-age z-scores stratified by gender. We decompose deviations from the reference values into an age-effect and a secular trend effect and find that after an initial increase in the 1940s, heights experienced a downward cycle to reach their early 1950s peak again only c. 2 decades later. After the early 1970s, heights increased almost continuously until the present. Girls born in 2002 are estimated to be 0.35sigma and boys are 0.39sigma above their 1971 values implying an increase of approximately 2.5 cm between birth cohorts 1971 and 2002 as an average of all ages (Table 3). Age effects are also substantial-pointing to faster tempo of growth. Girls are c. 0.23sigma taller at age 11 and boys 0.15sigma taller at age 13 than reference values (Fig. 3). This translates into an age effect of approximately 1.7 and 1.3 cm, respectively. Hence, the combined estimated trend and age-effects are substantially larger than those reported hitherto. The 2-decade stagnation in heights and the upward trend beginning in the early 1970s confirm the upswing in adult heights born c. 1975-1983, and imply that adults are likely to continue to increase in height. We find the expected positive correlation between height and family income, but income does not affect the secular trend or the age effects markedly.

Are Americans shorter (partly) because they are fatter? A comparison of US and Dutch children's height and BMI values.

OBJECTIVE: The study compared the height and BMI values of US children and youth by gender in the most recent NHANES surveys (1999-2004) to those of their Dutch counterparts in 1997 in order to gain insights into the different growth patterns. RESULTS: US children and youth are both shorter and heavier than their Dutch counterparts. US adolescent girls tend to experience an earlier growth spurt than do the Dutch and the velocity of growth of US boys slows down faster after the adolescent growth spurt than does that of their Dutch counterparts. The latter end up being approximately 5.6 cm taller and their median BMI values are 1.9-2.0 less than that of US youth between the ages of 10 and 19. This implies that US boys of the same height at age 19 are 8.8 kg heavier than their Dutch counterparts, and girls of age 13 are 7.2 kg heavier. DISCUSSION: Some studies link high BMI values in childhood to an earlier onset of adolescence, which in turn has been linked to less growth thereafter. CONCLUSION: The fast tempo of growth of the US children may be associated with high energy balance, which leads to higher BMI values and which in turn may be associated with less growth during adolescence.

Uranium reoxidation in previously bioreduced sediment by dissolved oxygen and nitrate.

Flow-through sediment column experiments examined the reoxidation of microbially reduced uranium with either oxygen or nitrate supplied as the oxidant. The uranium was reduced and immobilized via long-term (70 days) acetate biostimulation resulting in 62-92% removal efficiency of the 20 microM influent uranium concentration. Uranium reduction occurred simultaneously with iron reduction as the dominant electron accepting process. The columns were reoxidized by discontinuing the supply of acetate and either replacing the anaerobic gas used to purge the influent media with a gas mixture containing 20% oxygen (resulting in a dissolved oxygen concentration of 0.27 mM) or adding 1.6 mM nitrate to the influent media. Both oxygen and nitrate resolubilized the majority (88 and 97%, respectively) of the uranium precipitated during bioreduction within 54 days. Although oxygen is more thermodynamically favorable an oxidant than nitrate, nitrate-dependent uranium oxidation occurred significantly faster than oxygen-dependent uranium oxidation at the beginning of our experiment due, in part, to oxygen reacting more strongly with other reduced compounds. Nitrate breakthrough at the effluent of the column occurred within 12 h, which was significantly earlier than when oxygen was detected at the effluent (26 days). Although, over time, the majority of uranium was reoxidized by either oxidant, these results indicate that the type of oxidant and its reactivity with other reduced compounds will influence the fate of reduced uranium during a short-term oxidation event that may occur during a uranium bioremediation scenario.

The mysterious trend in American heights in the 20th century.

BACKGROUND: The secular trend in the height of the US population has been almost neglected in a comparative perspective, despite its being a useful indicator of early-life biological conditions. AIM: The study estimated the height of the US population and compared it to Western European trends after World War II. SUBJECTS AND METHOD: The complete set of NHES and NHANES data were analyzed, collected between 1959 and 2004 by the National Center for Health Statistics, in order to construct trends of the physical stature of US-born men and women limited to non-Hispanic blacks and whites. Also analyzed was the trend in the height of US military personnel whose parents were also born in the USA. The trends and levels were compared with those of several European populations. RESULTS: The increase in the physical stature of US adults slowed down by mid-century concurrent with a substantial acceleration in height attainment in Western and Northern Europe. Military data corroborate this finding in the main. After being the tallest population in the world ever since colonial times, Americans are now shorter than most Western and Northern Europeans and as much as 4.7-5.7 cm shorter than the Dutch, who are the tallest in world today. CONCLUSION: Given the well-established relationship between adult stature and early-life biological welfare, it was hypothesized that either American diets are sub-optimal or that the universal health care systems and social safety net of the European welfare states are providing a more favorable early-life health environment than does the American health care system.

Biostimulation of iron reduction and subsequent oxidation of sediment containing Fe-silicates and Fe-oxides: effect of redox cycling on Fe(III) bioreduction.

Sediment containing a mixture of iron (Fe)-phases, including Fe-oxides (mostly Al-goethite) and Fe-silicates (illites and vermiculite) was bioreduced in a long-term flow through column experiment followed by re-oxidation with dissolved oxygen. The objective of this study was (a) to determine the nature of the re-oxidized Fe(III), and (b) to determine how redox cycling of Fe would affect subsequent Fe(III)-bioavailability. In addition, the effect of Mn on Fe(III) reduction was explored.(57)Fe-Mössbauer spectroscopy measurements showed that biostimulation resulted in partial reduction (20%) of silicate Fe(III) to silicate Fe(II) while the reduction of goethite was negligible. Furthermore, the reduction of Fe in the sediment was uniform throughout the column. When, after biostimulation, 3900 pore volumes of a solution containing dissolved oxygen was pumped through the column over a period of 81 days, approximately 46% of the reduced silicate Fe(II) was re-oxidized to silicate Fe(III). The Mössbauer spectra of the re-oxidized sample were similar to that of pristine sediment implying that Fe-mineralogy of the re-oxidized sediment was mineralogically similar to that of the pristine sediment. In accordance to this, batch experiments showed that Fe(III) reduction occurred at a similar rate although time until Fe(II) buildup started was longer in the pristine sediment than re-oxidized sediment under identical seeding conditions. This was attributed to oxidized Mn that acted as a temporary redox buffer in the pristine sediment. The oxidized Mn was transformed to Mn(II) during bioreduction but, unlike silicate Fe(II), was not re-oxidized when exposed to oxygen.

Uranium removal from groundwater via in situ biostimulation: Field-scale modeling of transport and biological processes.

During 2002 and 2003, bioremediation experiments in the unconfined aquifer of the Old Rifle UMTRA field site in western Colorado provided evidence for the immobilization of hexavalent uranium in groundwater by iron-reducing Geobacter sp. stimulated by acetate amendment. As the bioavailable Fe(III) terminal electron acceptor was depleted in the zone just downgradient of the acetate injection gallery, sulfate-reducing organisms came to dominate the microbial community. In the present study, we use multicomponent reactive transport modeling to analyze data from the 2002 field experiment to identify the dominant transport and biological processes controlling uranium mobility during biostimulation, and determine field-scale parameters for these modeled processes. The coupled process simulation approach was able to establish a quantitative characterization of the principal flow, transport, and reaction processes based on the 2002 field experiment, that could be applied without modification to describe the 2003 field experiment. Insights gained from this analysis include field-scale estimates of the bioavailable Fe(III) mineral threshold for the onset of sulfate reduction, and rates for the Fe(III), U(VI), and sulfate terminal electron accepting processes.

Spatial correlates of us heights and body mass indexes, 2002.

Aiming to further explore possible underlying causes of the recent remarkable stagnation and relative decline in American heights, this paper describes the result of analysis of the commercial US Sizing Survey (2002). Heights are correlated positively with income and education among both white males and females while Body Mass Index (BMI) is correlated negatively among females, as in other samples. In contrast to much of the literature, this paper considers geographic correlates of height such as local poverty rate, median income and population density at the zip code level of resolution. After adjusting for confounding factors that influence height such as income and education, population density is found to be strongly and negatively correlated with height among white men, but less so among white women. The effect on BMIs less convincing. Other ethnic groups are not analysed in detail because of the small number of observations available. Local economic conditions as measured by median income, unemployment and poverty rate do not have a strong correlation with height or BMI after adjusting for individual income and education.

The height increments and BMI values of elite Central European children and youth in the second half of the 19th century.

BACKGROUND: Longitudinal height measurements on children and youth are very rare prior to the 20th century, as are BMI values. AIM: Growth increments and BMI values were determined among elite (select) Habsburg children and youth in the late 19th century and compared with other extant historical and contemporary data. SUBJECT AND METHODS: Archival data on height and weight were collected for approximately 3500 students attending Habsburg Military schools. The students were measured once a year for 4 years. Because of the minimum height requirement, truncated regression was used in order to estimate height trends, but standard procedures were used to determine height increments and BMI values. RESULTS: Heights increased at most 0.9-1.6 cm between the birth cohorts of circa 1870s and 1900. These future officers were about the same size as their counterparts in the USA and France, but smaller than those attending the Royal Military Academy in Sandhurst, England, who were taller and probably the tallest in the world at the time. Height increments were markedly smaller than those experienced by German students in the 18th century after age 15. Central European BMI values were above those obtained in the USA in the 19th century but well below modern values. CONCLUSION: Although peak height velocity was experienced as early as ages 13 and 14, the height increments were very small compared even to other historical populations. The military academy selected mainly precocious applicants (with probably larger height increments at younger ages and smaller increments at older ages). BMI values in this sample were well below modern standards, but they were unexpectedly as high as those of contemporary US West Point cadets, a well nourished group. There were significant differences in the height of elites in Central Europe in the 19th century, pointing to substantial socio-economic inequality, but at least the elites were as well nourished as the US population.

Effect of substrate concentration on dual-species biofilm population densities of Klebsiella oxytoca and Burkholderia cepacia in porous media.

The long-term operation of bioremediation technologies relies on the success of the contaminant-degrading microorganism(s) to compete for available resources with microorganisms already present in an aquifer or those that may contaminate a bioreactor. Though research has been performed studying the interaction of multiple species in batch and chemostat reactors, little work has been done looking at multi-species interactions in environments that more closely resemble field-scale applications. The research presented herein examined the interaction of Burkholderia cepacia PR1-pTOM(31c), an aerobic trichloroethylene (TCE)-degrading bacterium, with Klebsiella oxytoca, a facultative bacterium, in a flow-through porous media (PM) reactor. Growth characteristics and population distributions in PM were compared to previously reported values from batch and chemostat reactors. The faster growing organism in batch experiments (K. oxytoca) did not always have the greater population density in dual-species PM experiments. The biofilm population distribution was influenced by substrate concentration, with B. cepacia having a greater dual-species population density than K. oxytoca at a low (30 mg/L dissolved organic carbon [DOC]) substrate concentration and K. oxytoca having a greater population density at a high (700 mg/L DOC) substrate concentration. This change in species population distribution with change in substrate concentration, which was not observed in batch reactors, was also observed in chemostat reactors. Therefore, manipulation of substrate concentration enabled the control of species dominance to the advantage of the TCE degrading population in this dual-species PM system and may provide a mechanism to enhance bioremediation scenarios involving TCE or other contaminants of concern.