RESUMEN
Insect manure or "frass" has emerged as an alternative nutrient source for alleviating the dependence on fossil fuel-based fertilizers, reducing food waste, and promoting food security. Yet, research on insect frass chemical composition is in its infancy. Here, we assessed the chemical properties of yellow mealworm (Tenebrio molitor L.) frass compared with poultry litter (PL). Insect frass was obtained from the National Biological Control Laboratory (NBCL; IF-L) and an insect-rearing company (IF-C). PL was collected from facilities in Arkansas (PL-AR) and North Carolina (PL-NC). Samples were analyzed for pH, electrical conductivity, macro- and micronutrients, heavy metals, pathogens, and indicator microorganisms. On average, insect frass had 43% and 47% higher C and N than PL, respectively (Pâ <â 0.05). Considering a 5 mg/ha application rate, IF-C can supply 159 kg N/ha, twice the N supply of PL-AR (78 kg/ha). IF-L had a 53% higher P supply than PL-NC. Mean K, Ca, S, and micronutrient contents were higher in PL than in frass (Pâ <â 0.05), whereas As, Cd, Cr, and Pb were nearly absent in frass. Chemical composition and pathogens in fertilizer sources were largely affected by insect-rearing substrate and supplements used in poultry and insect production. Insect frass utilized in this study had optimum C and N rates relative to PL, suggesting a promising soil amendment for improving soil health and C sequestration, thus contributing to sustainable agricultural intensification and reuse of food waste in circular economies.
Asunto(s)
Fertilizantes , Estiércol , Fertilizantes/análisis , Animales , Estiércol/análisis , North Carolina , ArkansasRESUMEN
Microplastics have emerged as an important threat to terrestrial ecosystems. To date, little research has been conducted on investigating the effects of microplastics on ecosystem functions and multifunctionality. In this study, we conducted the pot experiments containing five plant communities consisting of Phragmites australis, Cynanchum chinense, Setaria viridis, Glycine soja, Artemisia capillaris, Suaeda glauca, and Limonium sinense and added polyethylene (PE) and polystyrene (PS) microbeads to the soil (contained a mixture of 1.5 kg loam and 3 kg sand) at two concentrations of 0.15 g/kg (lower concentration, hereinafter referred to as PE-L and PS-L) and 0.5 g/kg (higher concentration, hereinafter referred to as PE-H and PS-H) to explore the effects of microplastics on total plant biomass, microbial activity, nutrient supply, and multifunctionality. The results showed that PS-L significantly decreased the total plant biomass (p = 0.034), primarily by inhibiting the growth of the roots. ß-glucosaminidase decreased with PS-L, PS-H, and PE-L (p < 0.001) while the phosphatase was noticeably augmented (p < 0.001). The observation suggests that the microplastics diminished the nitrogen requirements and increased the phosphorus requirements of the microbes. The decrease in ß-glucosaminidase diminished ammonium content (p < 0.001). Moreover, PS-L, PS-H, and PE-H reduced the soil total nitrogen content (p < 0.001), and only PS-H considerably reduced the soil total phosphorus content (p < 0.001), affecting the ratio of N/P markedly (p = 0.024). Of interest, the impacts of microplastics on total plant biomass, ß-glucosaminidase, phosphatase, and ammonium content did not become larger at the higher concentration, and it is observable that microplastics conspicuously depressed the ecosystem multifunctionality, as microplastics depreciated single functions such as total plant biomass, ß-glucosaminidase, and nutrient supply. In perspective, measures to counteract this new pollutant and eliminate its impact on ecosystem functions and multifunctionality are necessary.
Asunto(s)
Ecosistema , Suelo , Poaceae , Microplásticos , Plásticos , Microesferas , Poliestirenos , Polietileno , Nutrientes , Nitrógeno , FósforoRESUMEN
This article aims to review research progress and provide future study on physicochemical, nutritional, and molecular structural characteristics of canola and rapeseed feedstocks and co-products from bio-oil processing and nutrient modeling evaluation methods. The review includes Canola oil seed production, utilization and features; Rapeseed oil seed production and canola oil seed import in China; Bio-processing, co-products and conventional evaluation methods; Modeling methods for evaluation of truly absorbed protein supply from canola feedstock and co-products. The article provides our current research in feedstocks and co-products from bio-oil processing which include Characterization of chemical and nutrient profiles and ruminal degradation and intestinal digestion; Revealing intrinsic molecular structures and relationship between the molecular structure spectra features and nutrient supply from feedstocks and co-products using advanced vibrational molecular spectroscopy technique. The study focused on advanced vibrational molecular spectroscopy which can be used as a fast tool to study molecular structure features of feedstock and co-products from bio-oil processing. The article also provides future in depth study areas. This review provides an insight as how to use advanced vibrational molecular spectroscopy for in-depth analysis of the relationship between molecular structure spectral feature and nutrition delivery from canola feedstocks and co-products from bio-oil processing.
Asunto(s)
Brassica napus , Brassica rapa , Aceite de Brassica napus/química , Brassica rapa/química , Nutrientes , Alimentación Animal/análisisRESUMEN
Patients receiving extracorporeal membrane oxygenation (ECMO) inherit substantial disease-associated metabolic, endocrinologic, and immunologic modifications. Along with the technical components of ECMO, the aforementioned alterations may affect patients' needs and feasibility of adequate macronutrient and micronutrient supply and intake. Thus, patients receiving ECMO are at increased risk for iatrogenic malnutrition and require targeted individual medical nutrition therapy (MNT). However, specific recommendations for MNT in patients receiving ECMO are limited and, with some exceptions, based on an evidence base encompassing general patients who are critically ill. Consequently, clinician decision-making for MNT in patients receiving ECMO is unguided, which may further increase nutrition risk, culminating in iatrogenic malnutrition and ultimately affecting patient outcomes. The purpose of this article is to provide educational background and highlight specific points for MNT in adult patients receiving ECMO, which might serve as evidence-based guidance to develop institutional standard operating procedures and nutrition protocols for daily clinical practice.
Asunto(s)
Oxigenación por Membrana Extracorpórea , Desnutrición , Adulto , Humanos , Oxigenación por Membrana Extracorpórea/métodos , Nutrición Enteral/métodos , Estado Nutricional , Enfermedad Crítica/terapia , Enfermedad IatrogénicaRESUMEN
BACKGROUND AND AIMS: Root proliferation is a response to a heterogeneous nutrient distribution. However, the growth of root hairs in response to heterogeneous nutrients and the relationship between root hairs and lateral roots remain unclear. This study aims to understand the effects of heterogeneous nutrients on root hair growth and the trade-off between root hairs and lateral roots in phosphorus (P) acquisition. METHODS: Near-isogenic maize lines, the B73 wild type (WT) and the rth3 root hairless mutant, were grown in rhizoboxes with uniform or localized supply of 40 (low) or 140 (high) mg P kg-1 soil. RESULTS: Both WT and rth3 had nearly two-fold greater shoot biomass and P content under local than uniform treatment at low P. Significant root proliferation was observed in both WT and rth3 in the nutrient patch, with the WT accompanied by an obvious increase (from 0.7 to 1.2 mm) in root hair length. The root response ratio of rth3 was greater than that of WT at low P, but could not completely compensate for the loss of root hairs. This suggests that plants enhanced P acquisition through complementarity between lateral roots and root hairs, and thus regulated nutrient foraging and shoot growth. The disappearance of WT and rth3 root response differences at high P indicated that the P application reduced the dependence of the plants on specific root traits to obtain nutrients. CONCLUSIONS: In addition to root proliferation, the root response to a nutrient-rich patch was also accompanied by root hair elongation. The genotypes without root hairs increased their investment in lateral roots in a nutrient-rich patch to compensate for the absence of root hairs, suggesting that plants enhanced nutrient acquisition by regulating the trade-off of complementary root traits.
Asunto(s)
Fósforo , Zea mays , Nutrientes , Raíces de Plantas , SueloRESUMEN
The aim of our study was to analyse vegetables, potatoes and their products as sources of energy and nutrients in the average diet in Poland. Representative data of the 2016 Household Budget Survey from 36,886 households were used. This is the largest study sample in Poland, so we generalized the conclusions to the whole population using the statement 'average diet'. We analysed three main product groups: vegetables, vegetable products, and potatoes and potatoes products, dividing them into 14 subgroups (e.g., tomatoes, cabbage, carrots, other vegetables, and mushrooms). The percentages of energy, protein, carbohydrates, total fat, nine vitamins (thiamine, riboflavin, niacin, vitamin B6, folate, vitamin C, vitamin A, vitamin D, and vitamin E), seven minerals (calcium, phosphorus, sodium, potassium, iron, magnesium and zinc), and fibre from the analysed food subgroups are presented. Additionally, the influence of household characteristics on the supply of energy and nutrients from each subgroup of vegetables, potatoes, and their products was evaluated using cluster analysis. In the analysis, R programme and Kohonen neural networks were applied. Our study showed that vegetables, potatoes, and their products provide 7.3% of daily dietary energy supply. Vegetables contribute more than 20% of the supply of six nutrients: vitamin C (51.8%), potassium (32.5%), folate (31.0%), vitamin A (30.6%), vitamin B6 (27.8%), and magnesium (20.2%), as well as fibre (31.8%). Cluster analysis distinguished three clusters that differed in nutritional supply from vegetables, potatoes, and their products. Educational level, income measured by quintile groups, village size, socio-economic characteristics, urbanization degree, and land use were the most important factors determining differences between clusters.
Asunto(s)
Solanum tuberosum , Verduras , Dieta , Encuestas sobre Dietas , Ingestión de Energía , Humanos , Nutrientes , Valor Nutritivo , PoloniaRESUMEN
BACKGROUND & AIMS: Excess nutrient supply, such as high fat and high glucose intake, promotes oxidative stress and advanced glycation end products accumulation. Oxidative stress and AGE accumulation cause pathological elevation of arginase activity and pro-inflammatory signaling implicated in endothelial dysfunction. Several studies showed positive effects of l-arginine supplementation in endothelial function but little is currently known about the role of l-arginine as prevention of endothelial dysfunction caused by excessive nutrient supply (overfeeding). Our aim was to evaluate a possible protective effect of l-arginine on endothelial dysfunction caused by excessive nutrient supply (overfeeding), using human endothelial cells line in an in vitro study. METHODS: Endothelial EA.hy926 cells were pre-treated with 1.72 mM of l-arginine for 24 h and afterwards subjected to nutritional stress (high lipid, high insulin and high glucose concentrations) for further 24 h. After treatment discontinuation, the cells were kept in culture for 48 h, in physiological condition, to evaluate the effects of treatments after normalization. RESULTS: Excess nutrient supply in EA.hy926 cell line showed an increase of oxidative and nitrosative stress, a rise of AGEs production, high arginase activity, leading the cells to acidosis and to cell death. l-arginine pretreatment protects the cells by reducing apoptosis, acidosis, oxidative and nitrosative stress, arginase activity and AGE accumulation. l-arginine pretreatment reduces AGEs generation and accumulation by regulating STAB1 and RAGE gene expression levels. STAB1, acting as receptor scavenger of AGEs, interferes with AGE-RAGE binding and thus prevents activation of intracellular signaling pathways leading to cell damage. Moreover the reduction of oxidative stress promotes a decrease of excessive activation of arginase involved in endothelial dysfunction. The effects of pretreatment with l-arginine last even in the absence of stimuli and despite after treatment discontinuation. CONCLUSIONS: An early l-arginine treatment is able to prevent oxidative stress and AGEs accumulation caused by overfeeding in human endothelial cell line by regulating STAB1/RAGE gene expression and by reducing excess arginase activity. The positive effects of l-arginine pretreatment continue even after treatment discontinuation in normal conditions.
Asunto(s)
Arginina/farmacología , Endotelio Vascular/efectos de los fármacos , Fenómenos Fisiológicos de la Nutrición/efectos de los fármacos , Hipernutrición/prevención & control , Sustancias Protectoras/farmacología , Línea Celular , Células Endoteliales/efectos de los fármacos , Productos Finales de Glicación Avanzada/metabolismo , Humanos , Hipernutrición/metabolismo , Estrés Oxidativo/efectos de los fármacos , Transducción de Señal/efectos de los fármacosRESUMEN
Vegetarian diets have gained popularity in sports. However, few data exist on the status of micronutrients and related biomarkers for vegetarian and vegan athletes. The aim of this cross-sectional study was to compare the micronutrient status of omnivorous (OMN, n = 27), lacto-ovo-vegetarian (LOV, n = 26), and vegan (VEG, n = 28) recreational runners. Biomarkers of vitamin B12, folate, vitamin D, and iron were assessed. Additionally, serum levels of calcium, magnesium, and zinc were examined. Lifestyle factors and supplement intake were recorded via questionnaires. About 80% of each group showed vitamin B12 adequacy with higher levels in supplement users. Mean red blood cell folate exceeded the reference range (>340 nmol/L) in all three groups (OMN: 2213 ± 444, LOV: 2236 ± 596, and VEG: 2354 ± 639 nmol/L; not significant, n.s.). Furthermore, vitamin D levels were comparable (OMN: 90.6 ± 32.1, LOV: 76.8 ± 33.7, and VEG: 86.2 ± 39.5 nmol/L; n.s.), and we found low prevalence (<20%) of vitamin D inadequacy in all three groups. Less than 30% of each group had depleted iron stores, however, iron deficiency anemia was not found in any subject. Our findings suggest that a well-planned, health-conscious lacto-ovo-vegetarian and vegan diet, including supplements, can meet the athlete's requirements of vitamin B12, vitamin D and iron.
Asunto(s)
Dieta Vegetariana , Dieta , Micronutrientes , Estado Nutricional , Carrera/fisiología , Adulto , Biomarcadores/sangre , Estudios Transversales , Dieta Vegana , Humanos , Hierro/administración & dosificación , Deficiencias de Hierro , Masculino , Micronutrientes/administración & dosificación , Micronutrientes/sangre , Necesidades Nutricionales , Veganos , Vitamina B 12/administración & dosificación , Vitamina B 12/sangre , Vitamina D/administración & dosificación , Vitamina D/sangre , Deficiencia de Vitamina D/sangreRESUMEN
BACKGROUND: The number of people preferring plant-based nutrition is growing continuously in the western world. Vegetarianism and veganism are also becoming increasingly popular among individuals participating in sport. However, whether recreationally active vegetarian and vegan populations can meet their nutritional needs is not clear. METHODS: The purpose of this cross-sectional study was to compare the nutrient intake of omnivorous (OMN, n = 27), lacto-ovo vegetarian (LOV, n = 25) and vegan (VEG, n = 27) recreational runners (two to five training sessions per week) with intake recommendations of the German, Austrian and Swiss Nutrition Societies (Deutsche, Österreichische und Schweizerische Gesellschaften für Ernährung, D-A-CH) for the general population. Lifestyle factors and supplement intake were examined via questionnaires; dietary habits and nutrient intake were determined based on 3-day dietary records. RESULTS: More than half of each group did not reach the recommended energy intake (OMN: 10.4, 8.70-12.1; LOV: 9.67, 8.55-10.8; VEG: 10.2, 9.12-11.3 MJ). Carbohydrate intake was slightly below the recommendations of > 50 EN% in OMN (46.7, 43.6-49.8 EN%), while LOV (49.4, 45.5-53.3 EN%) and VEG (55.2, 51.4-59.0 EN%) consumed adequate amounts (p = 0.003). The recommended protein intake of 0.8 g/kg body weight (D-A-CH) was exceeded in all three groups (OMN: 1.50, 1.27-1.66; LOV: 1.34, 1.09-1.56; VEG: 1.25; 1.07-1.42 g/kg BW; p = 0.047). Only VEG (26.3, 22.7-29.8 EN%) did not achieve the recommended fat intake of 30 EN%. The supply of micronutrients, such as vitamin D and cobalamin, was dependent on supplement intake. Additionally, female OMN and LOV achieved the recommended daily intake of 15 mg iron only after supplementation, while VEG consumed adequate amounts solely via food. CONCLUSION: All three groups were sufficiently supplied with most nutrients despite the exceptions mentioned above. The VEG group even showed advantages in nutrient intake (e.g. carbohydrates, fiber and iron) in comparison to the other groups. However, the demand for energy and several macro- and micronutrients might be higher for athletes. Thus, it is also necessary to analyze the endogenous status of nutrients to evaluate the influence of a vegetarian and vegan diet on the nutrient supply of athletes. TRIAL REGISTRATION: German Clinical Trial Register (DRKS00012377), registered on April 28, 2017.
RESUMEN
Humans are altering nutrient dynamics through myriad pathways globally. Concurrent with the addition of nutrients via municipal, industrial, and agricultural sources, widespread consumer exploitation is changing consumer-mediated nutrient dynamics drastically. Thus, altered nutrient dynamics can occur through changes in the supply of multiple nutrients, as well as through changes in the sources of these nutrients. Seagrass ecosystems are heavily impacted by human activities, with highly altered nutrient dynamics from multiple causes. We simulate scenarios of altered nutrient supply and ratios, nitrogen:phosphorus (N:P), from two nutrient sources in seagrass ecosystems: anthropogenic fertilizer and fish excretion. In doing so we tested expectations rooted in ecological theory that suggest the importance of resource dynamics for predicting primary producer dynamics. Ecosystem functions were strongly altered by artificial fertilizer (e.g., seagrass growth increased by as much as 140%), whereas plant/algae community structure was most affected by fish-mediated nutrients or the interaction of both treatments (e.g., evenness increased by ~140% under conditions of low fish nutrients and high anthropogenic nutrients). Interactions between the nutrient sources were found for only two of six response variables, and the ratio of nutrient supply was the best predictor for only one response. These findings show that seagrass structure and function are well predicted by supply of a single nutrient (either N or P). Importantly, no single nutrient best explained the majority of responses-measures of community structure were best explained by the primary limiting nutrient to this system (P), whereas measures of growth and density of the dominant producer in the system were best explained by N. Thus, while our findings support aspects of theoretical expectations, the complexity of producer community responses belies broad generalities, underscoring the need to manage for multiple simultaneous nutrients in these imperiled coastal ecosystems.
Asunto(s)
Ecosistema , Nutrientes , Animales , Peces , Nitrógeno , FósforoRESUMEN
Nitrogen (N) and phosphorus (P) have key roles in leaf metabolism, resulting in a strong coupling of chemical composition traits to metabolic rates in field-based studies. However, in such studies, it is difficult to disentangle the effects of nutrient supply per se on trait-trait relationships. Our study assessed how high and low N (5 mM and 0.4 mM, respectively) and P (1 mM and 2 µM, respectively) supply in 37 species from six plant functional types (PTFs) affected photosynthesis (A) and respiration (R) (in darkness and light) in a controlled environment. Low P supply increased scaling exponents (slopes) of area-based log-log A-N or R-N relationships when N supply was not limiting, whereas there was no P effect under low N supply. By contrast, scaling exponents of A-P and R-P relationships were altered by P and N supply. Neither R : A nor light inhibition of leaf R was affected by nutrient supply. Light inhibition was 26% across nutrient treatments; herbaceous species exhibited a lower degree of light inhibition than woody species. Because N and P supply modulates leaf trait-trait relationships, the next generation of terrestrial biosphere models may need to consider how limitations in N and P availability affect trait-trait relationships when predicting carbon exchange.
Asunto(s)
Ambiente Controlado , Nitrógeno/farmacología , Fósforo/farmacología , Hojas de la Planta/fisiología , Análisis de Varianza , Dióxido de Carbono/metabolismo , Luz , Nitrógeno/metabolismo , Fósforo/metabolismo , Fotosíntesis/efectos de la radiación , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Hojas de la Planta/efectos de la radiación , Carácter Cuantitativo Heredable , Almidón/metabolismo , Azúcares/metabolismoRESUMEN
The influence of nutrients on the growth of Ulva prolifera was studied in the SYS by field experiments. The wet weight of U. prolifera gradiently increased from 11.94% to 25.92% in proportion to contents of DIN supply, which indicated DIN content was essentially decisive for the output of U. prolifera blooms. Continuous nutrient supply could promote the growth of U. prolifera, indicated by the increase of growth rate from 10.46% of the batch culture to 42.17% of the in situ culture. The higher P utilized rate in all treatments showed P was the potential limited factor for the growth of U. prolifera. Moreover, it was calculated about 4.1×10(5)t organic matter was begot by U. prolifera in the whole Yellow Sea based on the statistical relationship between output of U. prolifera and DIN content. This work could be convenient to evaluate biomass and prepare enough tools to manage U. prolifera.
Asunto(s)
Ulva/crecimiento & desarrollo , Ulva/metabolismo , Contaminantes Químicos del Agua/metabolismo , Técnicas de Cultivo Celular por Lotes , Biomasa , China , Nitrógeno , Océanos y Mares , Fósforo/metabolismoRESUMEN
Corals thrive in low nutrient environments and the conservation of these globally imperiled ecosystems is largely dependent on mitigating the effects of anthropogenic nutrient enrichment. However, to better understand the implications of anthropogenic nutrients requires a heightened understanding of baseline nutrient dynamics within these ecosystems. Here, we provide a novel perspective on coral reef nutrient dynamics by examining the role of fish communities in the supply and storage of nitrogen (N) and phosphorus (P). We quantified fish-mediated nutrient storage and supply for 144 species and modeled these data onto 172 fish communities (71 729 individual fish), in four types of coral reefs, as well as seagrass and mangrove ecosystems, throughout the Northern Antilles. Fish communities supplied and stored large quantities of nutrients, with rates varying among ecosystem types. The size structure and diversity of the fish communities best predicted N and P supply and storage and N : P supply, suggesting that alterations to fish communities (e.g., overfishing) will have important implications for nutrient dynamics in these systems. The stoichiometric ratio (N : P) for storage in fish mass (~8 : 1) and supply (~20 : 1) was notably consistent across the four coral reef types (but not seagrass or mangrove ecosystems). Published nutrient enrichment studies on corals show that deviations from this N : P supply ratio may be associated with poor coral fitness, providing qualitative support for the hypothesis that corals and their symbionts may be adapted to specific ratios of nutrient supply. Consumer nutrient stoichiometry provides a baseline from which to better understand nutrient dynamics in coral reef and other coastal ecosystems, information that is greatly needed if we are to implement more effective measures to ensure the future health of the world's oceans.
Asunto(s)
Arrecifes de Coral , Peces , Nitrógeno/análisis , Fósforo/análisis , Animales , Teorema de Bayes , Ecosistema , Metabolismo Energético , Modelos Lineales , Modelos TeóricosRESUMEN
When the root system of a nutrient deficient plant is supplied locally with the nutrient, the roots grow and proliferate in the nutrient-rich zone, sometimes spectacularly so. In addition, uptake per unit of root is faster in the nutrient-rich zone. These are often thought of as compensatory responses. The extra surface area and faster uptake from the localized supply offset the inability of the rest of the root system to contribute to nutrient acquisition. This is the picture obtained from a few, well-known studies of young cereals. But is it supported by all the evidence that is available? This review assesses how various attributes respond to localized supplies of nutrients. The attributes are: root growth and development; uptake rates; nutrient contents; root;shoot interactions; and whole-plant growth. The nutrients considered are K, NH4 + , NO3 - and P. The experiments reviewed used techniques ranging from solution cultures to field studies. Most used as controls plants that were amply and uniformly supplied with the nutrient; some used plants uniformly deprived of the nutrient. One third of the measurements of root growth showed little or no response to a localized nutrient supply. Many others did, and the general tendency was for a stimulation of growth in a nutrient-rich zone to be mirrored by a suppression of growth elsewhere. Responses varied with time, species and nutrient. The response of a root system to locally available nutrients can be predicted in general terms. But the precise degree and direction of growth cannot. Simple rules of root development sometimes apply. But these cannot account for many other observations of development that do not follow any simple rule. Uptake per unit of root was usually up to c. three-fold faster when roots of nutrient-deprived plants were supplied locally. Exceptionally, increases of five- to ten-fold were measured. Generally, this increase was related inversely to the fraction of the root system with access to the nutrient. But within particular studies that relation did not hold. Root:shoot ratio usually increased or hardly changed in locally supplied plants. Their nutrient content usually declined more than growth. On average, therefore, the nutrient was less concentrated in the tissues of a locally supplied plant. This may indicate the diversion or mobilization of nutrients from potential storage pools to supplement the amounts taken up from the localized supply. An exception to this was for N in the one C4 species studied, Zea mays. When comparing these attributes, the growth of whole plants was least affected by a non-uniform supply of nutrients, and least variable. This is circumstantial evidence that some of the responses did compensate partially for non-uniform supplies of nutrients. But within species and nutrient treatments, there was no consistent association between specific responses and any apparent compensation. Contents Summary 635 I. Introduction 636 II. Experimental methods 638 III. Root growth 642 IV. Uptake rate per unit of root 647 V. Xutrient content 648 VI. Root: shoot partitioning 649 VII. Growth: do responses compensate? 649 VIII. Conclusions 652 Acknowledgements 653 References 653 Appendix 656.