Phosphorus Removal in Constructed Stormwater Wetland Mesocosms Amended with Water Treatment Residuals.

Constructed stormwater wetlands (CSWs) reduce stormwater volume and improve water quality. One quality improvement is the removal of soluble reactive phosphorus (SRP). There has been limited study on SRP fate and transport or on the mechanisms to improve SRP removal due to the difficulty in quantifying the complex, spatially heterogeneous removal processes in two-dimensional flow. The present research analyzed the ability of wetland soil (Control) and wetland soil amended with 2%, 5%, and 8% (by mass) of aluminum-based water treatment residuals (AlWTRs) to remove SRP in surface-flow vegetated CSW mesocosms. Batch adsorption experiments showed increasing SRP sorption capacity with increased AlWTR content (590-850 mg/kg soil) compared to the Control (385 mg/kg soil); however, AlWTR-amended flowing mesocosms removed only 6.0-8.8 mg/kg SRP compared to 9.3 mg/kg SRP for the Control. The lack of increased SRP removal in AlWTR-amended mesocosms was attributed to flow dynamics (only 20% of the surface outflow was quantified as subsurface flow). These results suggest the extent of infiltration versus surface flow is key to soil amendments improving SRP removal in a CSW.

Microbial reduction of uranium under iron- and sulfate-reducing conditions: Effect of amended goethite on microbial community composition and dynamics.

There is a growing need for a better understanding of the biogeochemical dynamics involved in microbial U(VI) reduction due to an increasing interest in using biostimulation via electron donor addition as a means to remediate uranium contaminated sites. U(VI) reduction has been observed to be maximized during iron-reducing conditions and to decrease upon commencement of sulfate-reducing conditions. There are many unknowns regarding the impact of iron/sulfate biogeochemistry on U(VI) reduction. This includes Fe(III) availability as well as the microbial community changes, including the activity of iron-reducers during the uranium biostimulation period even after sulfate reduction becomes dominant. Column experiments were conducted with Old Rifle site sediments containing Fe-oxides, Fe-clays, and sulfate rich groundwater. Half of the columns had sediment that was augmented with small amounts of Fe(III) in the form of (57)Fe-goethite, allowing for a detailed tracking of minute changes of this added phase to study the effects of increased Fe(III) levels on the overall biostimulation dynamics. Mössbauer spectroscopy showed that the added (57)Fe-goethite was bioreduced only during the first thirty days of biostimultuion, after which it remained constant. Augmentation with Fe(III) had a significant effect on the total flux of electrons towards different electron acceptors; it suppressed the degree of sulfate reduction, had no significant impact on Geobacter-type bacterial numbers but decreased the bacterial numbers of sulfate reducers and affected the overall microbial community composition. The addition of Fe(III) had no noticeable effect on the total uranium reduction.

Biogenic U(IV) oxidation by dissolved oxygen and nitrate in sediment after prolonged U(VI)/Fe(III)/SO(4)(2-) reduction.

Sediment column experiments were performed to quantify the effect of biogenic iron sulfide precipitates on the stability of bioreduced uranium during and after a simulated bioremediation scenario. In particular, this study examined the effect of different oxidants (dissolved oxygen and nitrate) on biogenic U(IV) oxidation in sediment that experienced significant sulfate reduction in addition to Fe(III) and U(VI) reduction. The experimental set-up included five replicate columns (each 5 cm in diameter, 15 cm long and packed with background sediment from a site contaminated with uranium) that were bioreduced for 70 days by injecting a nutrient media containing 3 mM acetate and 6 mM sulfate prior to oxidation. Upon oxidation, iron sulfide precipitates formed during bioreduction acted as a buffer to partially prevent biogenic U(IV) oxidation. The iron sulfides were more effective at protecting biogenic U(IV) from oxidation when dissolved oxygen was the oxidant compared to nitrate. A constant supply of 0.25 mM and 1.6 mM nitrate over a 50 day period resulted in uranium resolubilization of 11% and 60%, respectively, while less than 1% of the uranium was resolubilized in the column supplied 0.27 mM dissolved oxygen during the same time period. Over time, oxidation increased pore water channeling, which was more pronounced during oxidation with nitrate. Increased channeling with time of oxidation could affect the transport of an oxidant through the previously reduced zone, and hence the oxidation dynamics of the reduced species.

Interaction of Klebsiella oxytoca and Burkholderia cepacia in dual-species batch cultures and biofilms as a function of growth rate and substrate concentration.

Dual-species microbial interactions have been extensively reported for batch and continuous culture environments. However, little research has been performed on dual-species interaction in a biofilm. This research examined the effects of growth rate and substrate concentration on dual-species population densities in batch and biofilm reactors. In addition, the feasibility of using batch reactor kinetics to describe dual-species biofilm interactions was explored. The scope of the research was directed toward creating a dual-species biofilm for the biodegradation of trichloroethylene, but the findings are a significant contribution to the study of dual-species interactions in general. The two bacterial species used were Burkholderia cepacia PR1-pTOM(31c), an aerobic organism capable of constitutively mineralizing trichloroethylene (TCE), and Klebsiella oxytoca, a highly mucoid, facultative anaerobic organism. The substrate concentrations used were different dilutions of a nutrient-rich medium resulting in dissolved organic carbon (DOC) concentrations on the order of 30, 70, and 700 mg/L. Presented herein are single- and dual-species population densities and growth rates for these two organisms grown in batch and continuous-flow biofilm reactors. In batch reactors, planktonic growth rates predicted dual-species planktonic species dominance, with the faster-growing organism (K. oxytoca) outcompeting the slower-growing organism (B. cepacia). In a dual-species biofilm, however, dual-species planktonic growth rates did not predict which organism would have the higher dual-species biofilm population density. The relative fraction of each organism in a dual-species biofilm did correlate with substrate concentration, with B. cepacia having a greater proportional density in the dual-species culture with K. oxytoca at low (30 and 70 mg/L DOC) substrate concentrations and K. oxytoca having a greater dual-species population density at a high (700 mg/L DOC) substrate concentration. Results from this research demonstrate the effectiveness of using substrate concentration to control population density in this dual-species biofilm.

Social status and adult heights in the two Germanies.

BACKGROUND: Lack of evidence prevented hitherto the systematic comparison of physical stature across East and West Germany. AIM: The aim of this study is to compare heights by social status in the two Germanies with very different socio-economic and political systems prior to unification. DATA: The German Federal Health Survey of 1998 (Public Use File BGS98), a cross-sectional random sample of 7124 adult males and females between ages 18 and 79 (birth cohorts of 1919-1980) is used in the analysis. RESULTS: There are considerable and persistent differences by social status in both East and West Germany over time. The West German height advantage among men increases with social status, whereas among women the opposite is the case. East German men born after the Berlin Wall was built became significantly shorter, but East Germans regained equality with West Germans after unification. In contrast, East German females were markedly shorter than their West German counterparts throughout the period considered. CONCLUSIONS: The West German capitalistic welfare state provided a more propitious environment for the physical growth of the human organism than did the socialist East German government. There were substantial social differences in height in the officially classless German Democratic Republic.

[Modern economic growth and biological status]. / Modernes ökonomisches Wachstum und biologischer Lebensstandard.

One of the most important recent findings of the anthropometric history research program is that human beings were becoming shorter at the onset of modern economic growth. There were hidden stresses on the biological system created by the new socio-economic environment that were not fully compensated by increases in income. This essay gives the outlines of an explanation for the "early-industrial-growth puzzle".

[On the importance of anthropometric history]. / De l'importance de l'histoire anthropométrique.

One can think of the average height at a particular age by individuals in a population as the historical record of their nutritional experience. Medical research has confirmed that nutritional status--and thus physical stature--, is related to food consumption and therefore to real family income, and therefore to wages and to prices and variables. Through anthropometric research one can illuminate the biological well being of some members of a society--women, children, aristocrats, subsistence farmers and slaves--, for whom market wages are seldom available. In additiion, it has been shown that the biological standard of living can diverge from conventional indicators of well being during the early stages of industrialization. These are noteworthy contributions to the frontiers of knowledge in economic and demographic history.

The growth of boys in the Stuttgart Carlschule, 1771-93.

Height measurements taken in a mixed longitudinal manner on 1084 German-born boys aged 7 to 21+ at the Carlschule Academy in Stuttgart during the period 1771-93 have been examined. The boys can be divided into upper (aristocrat), middle and lower (artisan, servant) classes, nearly all housed and fed in this boarding school. Preece-Baines curves have been fitted to a subsample of 155 boys whose measurements cover at least the period 12-16 years at a density of two or three per year. In addition, the whole data, totalling 11,040 observations, have been examined as if purely cross-sectional; and the height-at-entry measurement for each of 670 students has been examined. The results of the longitudinal subsample and the cross-sectional analyses agree reasonably well. Social class differences existed both in tempo of growth as signified by age at peak height velocity, and in adult height. The longitudinal analysis gives adult differences of about 2 cm between upper and middle classes and a further 2 cm between middle and lower, even amongst these boys all resident in the same, very privileged, school. Tempo differences between upper and middle class were minor, amounting to only 0.3 year, but lower-class boys had their maximum growth increment about a year later than the others. Amongst middle classes a secular trend of about 2 cm averaged over all ages was found between those born before 1770 and those born later. This mainly represents a trend in tempo rather than in adult height. The heights of these boys are compared with those of contemporary Austrian upper and lower classes, English upper and lower classes, American Army cadets, and American slaves. The increase in German middle-class heights during the 18th century indicates that this group was improving its nutritional status and well-being, at a time when the heights of the remainder of the population were constant or declining. This is evidence in favour of the view that at the beginning of economic development the distribution of income tends to become more skewed.

Mathematical investigations of the escape from the Malthusian trap.

"We present a simulation model that synthesizes Malthusian and Boserupian notions of the way population growth and economic development were intertwined. The non-linear stochastic model consists of a system of equations whose dynamics culminate in an industrial revolution after hundreds of iterations. The Industrial Revolution [in Europe] can thus be conceptualized as a permanent 'escape' from the Malthusian trap that occurs once the economy is capable of permanently sustaining an ever growing population. We investigate the conditions for such an escape and their sensitivity to the parameters of the model.... Our results show that the likelihood of an escape is sensitive to the savings rate and to the output elasticities of the two sectors of the economy. When not in a subsistence crisis, the chances that an escape will occur increase for larger values of the ratio of the savings rate to the growth rate of the population. The chances of an escape also increase substantially for larger values of the output elasticities of labor." (SUMMARY IN FRE)

The age at menarche and age at first birth in an undernourished population.

A statistically significant relationship has been found between the age at menarche and the age at first birth among chronically-malnourished, lower-class Viennese women born in the late nineteenth century. Because the age at menarche depends on nutritional status, the above relationship is an indication that nutritional status must also have correlated positively with fertility rate, and therefore with population growth in societies with similar characteristics as this sample. Thus, the nutrition sensitivity of the age of first birth, and therefore of population growth are established in a chronically malnourished non-contraceptive historical population.

PIP: A statistically significant relationship has been found between the age at menarche and the age of 1st birth among chronically-malnourished, lower-class Viennese women born in the late 19th century. Because the age at menarche depends on nutritional status, the above relationship is an indication that nutritional status must also have correlated positively with fertility rate, and therefore with population growth in societies with similar characteristics as this sample. Thus, the nutrition sensitivity of the age of 1st birth, and therefore of population growth are established in a chronically malnourished noncontraceptive historical population. (author's)

Population growth and economic development in the very long run: a simulation model of three revolutions.

The authors propose an economic model capable of simulating the 4 main historical stages of civilization: hunting, agricultural, industrial, and postindustrial. An output-maximizing society to respond to changes in factor endowments by switching technologies. Changes in factor proportions arise through population growth and capital accumulation. A slow rate of exogenous technical process is assumed. The model synthesizes Malthusian and Boserupian notions of the effect of population growth on per capita output. Initially the capital-diluting effect of population growth dominates. As population density increases, however, and a threshold is reached, the Boserupian effect becomes crucial, and a technological revolution occurs. The cycle is thereafter repeated. After the second economic revolution, however, the Malthusian constraint dissolves permanently, as population growth can continue without being constrained by diminishing returns to labor. By synthesizing Malthusian and Boserupian notions, the model is able to capture the salient features of economic development in the very long run.

Patterns of children's growth in east-central Europe in the eighteenth century.

Records in Vienna of the heights of (a) Military Academy youths born between 1730 and 1760, (b) orphanage children born between 1760 and 1780 and (c) military boarding-school children born between 1775 and 1815 have been retrieved and analysed. This constitutes the earliest extant set of measurements of the heights of a group of individuals. Stature was increasing in the late 1740s and decreasing after the 1770s. This evidence indicates a rise and subsequent fall in nutritional status and is consistent with the known pattern of European agricultural conditions in the eighteenth century. Shifts in the age of maximum increment support the notion of the secular changes in the nutritional status of these boys. The stature of the Habsburg boys was greater than the poorest boys of contemporary London but compared unfavourably with the height of the English gentry and American cadets of the nineteenth century and, of course, with the height of today's populations.

Population growth through history and the escape from the Malthusian trap: a homeostatic simulation model.

"A Malthusian simulation model is proposed to describe the growth of human population from the Neolithic through the Industrial Revolution. The economy is composed of a subsistence sector and a capital-producing sector. Our model captures the 'incessant contest' between population growth and the means of subsistence. When the per capita agricultural output falls below a biological minimum, the growth rate of the population is subject, in a random fashion, to perturbations that can take on disastrous proportions." It is suggested that "the slow accumulation of capital (and the buildup of the population of the capital-producing sector) eventually enables the population to overcome the constraints of the hostile economic environment. Our simulations (complete with confidence intervals) yield numerically realistic estimates of the population that eventually escapes from the Malthusian menace and grows unhindered during the Industrial Revolution." (summary in FRE, ITA)