Science.gov

Sample records for modeling nutrient consumptions

  1. A novel coupled system of non-local integro-differential equations modelling Young's modulus evolution, nutrients' supply and consumption during bone fracture healing

    NASA Astrophysics Data System (ADS)

    Lu, Yanfei; Lekszycki, Tomasz

    2016-10-01

    During fracture healing, a series of complex coupled biological and mechanical phenomena occurs. They include: (i) growth and remodelling of bone, whose Young's modulus varies in space and time; (ii) nutrients' diffusion and consumption by living cells. In this paper, we newly propose to model these evolution phenomena. The considered features include: (i) a new constitutive equation for growth simulation involving the number of sensor cells; (ii) an improved equation for nutrient concentration accounting for the switch between Michaelis-Menten kinetics and linear consumption regime; (iii) a new constitutive equation for Young's modulus evolution accounting for its dependence on nutrient concentration and variable number of active cells. The effectiveness of the model and its predictive capability are qualitatively verified by numerical simulations (using COMSOL) describing the healing of bone in the presence of damaged tissue between fractured parts.

  2. Energy-consumption modelling

    SciTech Connect

    Reiter, E.R.

    1980-01-01

    A highly sophisticated and accurate approach is described to compute on an hourly or daily basis the energy consumption for space heating by individual buildings, urban sectors, and whole cities. The need for models and specifically weather-sensitive models, composite models, and space-heating models are discussed. Development of the Colorado State University Model, based on heat-transfer equations and on a heuristic, adaptive, self-organizing computation learning approach, is described. Results of modeling energy consumption by the city of Minneapolis and Cheyenne are given. Some data on energy consumption in individual buildings are included.

  3. Oxygen Consumption Rates of Bacteria under Nutrient-Limited Conditions

    PubMed Central

    Riedel, Timothy E.; Nealson, Kenneth H.; Finkel, Steven E.

    2013-01-01

    Many environments on Earth experience nutrient limitation and as a result have nongrowing or very slowly growing bacterial populations. To better understand bacterial respiration under environmentally relevant conditions, the effect of nutrient limitation on respiration rates of heterotrophic bacteria was measured. The oxygen consumption and population density of batch cultures of Escherichia coli K-12, Shewanella oneidensis MR-1, and Marinobacter aquaeolei VT8 were tracked for up to 200 days. The oxygen consumption per CFU (QO2) declined by more than 2 orders of magnitude for all three strains as they transitioned from nutrient-abundant log-phase growth to the nutrient-limited early stationary phase. The large reduction in QO2 from growth to stationary phase suggests that nutrient availability is an important factor in considering environmental respiration rates. Following the death phase, during the long-term stationary phase (LTSP), QO2 values of the surviving population increased with time and more cells were respiring than formed colonies. Within the respiring population, a subpopulation of highly respiring cells increased in abundance with time. Apparently, as cells enter LTSP, there is a viable but not culturable population whose bulk community and per cell respiration rates are dynamic. This result has a bearing on how minimal energy requirements are met, especially in nutrient-limited environments. The minimal QO2 rates support the extension of Kleiber's law to the mass of a bacterium (100-fg range). PMID:23770901

  4. Levels of nutrients in relation to fish consumption among older male anglers in Wisconsin

    PubMed Central

    Christensen, Krista Y.; Thompson, Brooke A.; Werner, Mark; Malecki, Kristen; Imm, Pamela; Anderson, Henry A.

    2016-01-01

    Fish are an important source of nutrients including omega-3 fatty acids, which may reduce risk of adverse health outcomes such as cardiovascular disease; however, fish may also contain significant amounts of environmental pollutants. The Wisconsin Departments of Health Services and Natural Resources developed a survey instrument, along with a strategy to collect human biological samples to assess the risks and benefits associated with long-term fish consumption among older male anglers in Wisconsin. The target population was men aged 50 years and older, who fish Wisconsin waters and live in the state of Wisconsin. Participants provided blood and hair samples and completed a detailed (paper) questionnaire, which included questions on basic demographics, health status, location of catch and species of fish caught/eaten, consumption of locally caught and commercially purchased fish, and awareness and source of information for local and statewide consumption guidelines. Biological samples were used to assess levels of docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), eicosapentaenoic acid (EPA); vitamin D; and selenium in blood. Quantile regression analysis was used to investigate the associations between biomarker levels and self-reported consumption of fish from the Great Lakes and other areas of concern, other locally caught fish, and commercially purchased fish (meals per year). Respondents were largely non-Hispanic white men in their 60’s with at least some college education, and about half were retired. Fish consumption was high (median of 54.5 meals per year), with most fish meals coming from locally-caught fish. Multivariate regression models showed that the effect of supplement use was much greater than that of fish consumption, on nutrient levels, although consumption of fish from the Great Lakes and areas of concern was significantly associated with higher levels of vitamin D even after controlling for supplement usage. PMID:26296180

  5. Nut consumption is associated with better nutrient intakes: results from the 2008/09 New Zealand Adult Nutrition Survey.

    PubMed

    Brown, Rachel C; Tey, Siew Ling; Gray, Andrew R; Chisholm, Alex; Smith, Claire; Fleming, Elizabeth; Parnell, Winsome

    2016-01-14

    A limited number of studies have examined associations between nut consumption and nutrient intakes or diet quality. None has investigated these associations in the Southern Hemisphere. The purpose of this study was to examine associations between nut consumption and nutrient intakes among adult New Zealanders. Data from the 24-h recalls of 4721 participants from the cross-sectional 2008/09 New Zealand Adult Nutrition Survey (2008/09 NZANS) were used to determine whole nut intake and total nut intake from all sources as well as nutrient intakes. Regression models, both unadjusted and adjusted for potential confounders, were used to estimate differences in nutrient intakes between those consuming and those not consuming nuts. From adjusted models, compared with non-whole nut consumers, whole nut consumers had higher intakes of energy and percentage of energy from total fat, MUFA and PUFA, whereas percentage of energy from SFA and carbohydrate was lower (all P≤0·025). After the additional adjustment for energy intake, whole nut consumers had higher intakes of dietary fibre, vitamin E, folate, Cu, Mg, K, P and Zn (all P≤0·044), whereas cholesterol and vitamin B12 intakes were significantly lower (both P≤0·013). Total nut consumption was associated with similar nutrient profiles as observed in whole nut consumers, albeit less pronounced. Nut consumption was associated with better nutrient profiles, especially a lower intake of SFA and higher intakes of unsaturated fats and a number of vitamins and minerals that could collectively reduce the risk for chronic disease, in particular for CVD.

  6. Nutrient Intakes and Vegetable and White Potato Consumption by Children Aged 1 to 3 Years.

    PubMed

    Storey, Maureen L; Anderson, Patricia A

    2016-01-01

    In 2020, for the first time, the Dietary Guidelines for Americans will include recommendations for children from birth to age 24 mo. We examined average nutrient intakes as well as total vegetable and white potato (WP) consumption among children aged 1-3 y using day 1 dietary data from the NHANES 2009-2012 and the Food Patterns Equivalents Database 2009-2012. Appropriate survey weights were used to calculate average daily consumption of total vegetables and WPs, which included French-fried potatoes and chips, for boys and girls aged 1-3 y. We calculated mean intakes of selected nutrients of concern, including vitamin D, potassium, dietary fiber (DF), and calcium. We also examined intakes of selected nutrients by major food group. Average intakes of most nutrients, including calcium, by children aged 1-3 y exceeded Dietary Reference Intakes (DRIs). However, average intakes of potassium, DF, and vitamin D were 67%, 55%, and 49% of DRIs, respectively. Mean total vegetable intake was less than the recommendation of 1 cup/d. Boys and girls aged 1-3 y consumed an average of 0.58 cup equivalents of total vegetables on the day of the survey, which included 0.16 cups of WPs. Average vegetable consumption and mean intakes of potassium, DF, and vitamin D were far below recommendations. The consumption of all vegetables, particularly those that are excellent sources of potassium and DF, such as potatoes, should be encouraged.

  7. Nutrient Intakes and Vegetable and White Potato Consumption by Children Aged 1 to 3 Years.

    PubMed

    Storey, Maureen L; Anderson, Patricia A

    2016-01-01

    In 2020, for the first time, the Dietary Guidelines for Americans will include recommendations for children from birth to age 24 mo. We examined average nutrient intakes as well as total vegetable and white potato (WP) consumption among children aged 1-3 y using day 1 dietary data from the NHANES 2009-2012 and the Food Patterns Equivalents Database 2009-2012. Appropriate survey weights were used to calculate average daily consumption of total vegetables and WPs, which included French-fried potatoes and chips, for boys and girls aged 1-3 y. We calculated mean intakes of selected nutrients of concern, including vitamin D, potassium, dietary fiber (DF), and calcium. We also examined intakes of selected nutrients by major food group. Average intakes of most nutrients, including calcium, by children aged 1-3 y exceeded Dietary Reference Intakes (DRIs). However, average intakes of potassium, DF, and vitamin D were 67%, 55%, and 49% of DRIs, respectively. Mean total vegetable intake was less than the recommendation of 1 cup/d. Boys and girls aged 1-3 y consumed an average of 0.58 cup equivalents of total vegetables on the day of the survey, which included 0.16 cups of WPs. Average vegetable consumption and mean intakes of potassium, DF, and vitamin D were far below recommendations. The consumption of all vegetables, particularly those that are excellent sources of potassium and DF, such as potatoes, should be encouraged. PMID:26773032

  8. Electric-field-enhanced nutrient consumption in dielectric biomaterials that contain anchorage-dependent cells.

    PubMed

    Belfiore, Laurence A; Floren, Michael L; Belfiore, Carol J

    2012-02-01

    This research contribution addresses electric-field stimulation of intra-tissue mass transfer and cell proliferation in viscoelastic biomaterials. The unsteady state reaction-diffusion equation is solved according to the von Kármán-Pohlhausen integral method of boundary layer analysis when nutrient consumption and tissue regeneration occur in response to harmonic electric potential differences across a parallel-plate capacitor in a dielectric-sandwich configuration. The partial differential mass balance with diffusion and electro-kinetic consumption contains the Damköhler (Λ(2)) and Deborah (De) numbers. Zero-field and electric-field-sensitive Damköhler numbers affect nutrient boundary layer growth. Diagonal elements of the 2nd-rank diffusion tensor are enhanced in the presence of weak electric fields, in agreement with the formalism of equilibrium and nonequilibrium thermodynamics. Induced dipole polarization density within viscoelastic biomaterials is calculated via the real and imaginary components of the complex dielectric constant, according to the Debye equation, to quantify electro-kinetic stimulation. Rates of nutrient consumption under zero-field conditions are described by third-order kinetics that include local mass densities of nutrients, oxygen, and attached cells. Thinner nutrient boundary layers are stabilized at shorter dimensionless diffusion times when the zero-field intra-tissue Damköhler number increases above its initial-condition-sensitive critical value [i.e., {Λ(2)(zero-field)}(critical)≥53, see Eq. (23)], such that the biomaterial core is starved of essential ingredients required for successful proliferation. When tissue regeneration occurs above the critical electric-field-sensitive intra-tissue Damköhler number, the electro-kinetic contribution to nutrient consumption cannot be neglected. The critical electric-field-sensitive intra-tissue Damköhler number is proportional to the Deborah number.

  9. Consumption Patterns of Fruit and Vegetable Juices and Dietary Nutrient Density among French Children and Adults

    PubMed Central

    Francou, Aurée; Hebel, Pascale; Braesco, Véronique; Drewnowski, Adam

    2015-01-01

    Background: Fruit and vegetable consumption is a marker of higher-quality diets; less is known about the contribution of 100% fruit and vegetable juices (FVJ) to diet quality. Objective: To explore FVJ consumption patterns in relation to dietary nutrient density among French children (aged 3–14 years old) and adults (≥21 years old). Methods: Analyses were based on the nationally representative 2013 CCAF (Comportements et Consommations Alimentaires en France) survey of 1930 respondents, stratified by age group, FVJ consumption, and socioeconomic status (SES). Dietary nutrient density was based on the Nutrient Rich Food (NRF9.3) index, adjusted for gender and age. Results: Mean total consumption of fruits and vegetables was 2.6 servings/day for children and 3.8 servings/day for adults. Mean population consumption of FVJ was 83 mL/day for children and 54.6 mL/day for adults, equivalent to 0.4 servings/day and 0.3 servings/day respectively. FVJ consumers had higher quality diets than did non-consumers, after adjusting for covariates. The respective NRF9.3 values were 486.4 ± 4.3 vs. 428.7 ± 7.5 for children and 460.7 ± 4.4 vs. 435.4 ± 4.4 for adults. FVJ consumers had similar or higher intakes of fruits and vegetables than did non-consumers. The socioeconomic gradient for FVJ consumption was much weaker (p < 0.046) than for whole fruit (p < 0.01). Conclusions: In a nationally representative sample of French children and adults, fruit and vegetable consumption fell short of recommended values. Higher FVJ consumption was associated with higher-quality diets and better compliance with the French National Plan for Nutrition and Health (PNNS). PMID:26213964

  10. Household Food Expenditure Patterns, Food Nutrient Consumption and Nutritional Vulnerability in Nigeria: Implications for Policy.

    PubMed

    Akerele, Dare

    2015-01-01

    The study examined the patterns of food spending, food nutrient consumption, and nutrient deficiency profiles of households in Nigeria using a cross-sectional nationwide household survey data. Food nutrients were estimated from food expenditure data while the nutrient deficiency profiles were assessed adapting Foster et al. (1984) poverty index. The study established widespread nutritional deficiencies with low-income household cohorts bearing a greater burden of the deficiencies. Protein-protein deficiency appears to be much more prevalent in urban than rural areas. However, the deficiency of micro-nutrients seems to diffuse across urban-rural divides of the country with deficiency of calcium, vitamin A, and vitamin C appearing to be more pronounced in rural areas while phosphorous, vitamin B1, vitamin B2, and vitamin B3 deficiencies seem to be higher in urban settings. Pro-poor income growth strategies and sensitively guided urban-rural food and nutrition interventions are advocated for improved food consumption and nutritional deficiency reduction. PMID:26083997

  11. Almond consumption is associated with better nutrient intake, nutrient adequacy, and diet quality in adults: National Health and Nutrition Examination Survey 2001-2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to examine the association between almond consumption, the most widely consumed tree nut in the US, and nutrient intake, nutrient adequacy, diet quality, and weight/adiposity in adults. Data from adults (N=24,808), 19+ years, participating in the NHANES 2001-2010 were u...

  12. Frequent Canned Food Use is Positively Associated with Nutrient-Dense Food Group Consumption and Higher Nutrient Intakes in US Children and Adults.

    PubMed

    Comerford, Kevin B

    2015-07-01

    In addition to fresh foods, many canned foods also provide nutrient-dense dietary options, often at a lower price, with longer storage potential. The aim of this study was to compare nutrient-dense food group intake and nutrient intake between different levels of canned food consumption in the US. Consumption data were collected for this cross-sectional study from 9761 American canned food consumers (aged two years and older) from The NPD Group's National Eating Trends® (NET®) database during 2011-2013; and the data were assessed using The NPD Group's Nutrient Intake Database. Canned food consumers were placed into three groups: Frequent Can Users (≥6 canned items/week); n = 2584, Average Can Users (3-5 canned items/week); n = 4445, and Infrequent Can Users (≤2 canned items/week); n = 2732. The results provide evidence that Frequent Can Users consume more nutrient-dense food groups such as fruits, vegetables, dairy products, and protein-rich foods, and also have higher intakes of 17 essential nutrients including the shortfall nutrients-potassium, calcium and fiber-when compared to Infrequent Can Users. Therefore, in addition to fresh foods, diets higher in nutrient-dense canned food consumption can also offer dietary options which improve nutrient intakes and the overall diet quality of Americans. PMID:26184294

  13. Frequent Canned Food Use is Positively Associated with Nutrient-Dense Food Group Consumption and Higher Nutrient Intakes in US Children and Adults.

    PubMed

    Comerford, Kevin B

    2015-07-09

    In addition to fresh foods, many canned foods also provide nutrient-dense dietary options, often at a lower price, with longer storage potential. The aim of this study was to compare nutrient-dense food group intake and nutrient intake between different levels of canned food consumption in the US. Consumption data were collected for this cross-sectional study from 9761 American canned food consumers (aged two years and older) from The NPD Group's National Eating Trends® (NET®) database during 2011-2013; and the data were assessed using The NPD Group's Nutrient Intake Database. Canned food consumers were placed into three groups: Frequent Can Users (≥6 canned items/week); n = 2584, Average Can Users (3-5 canned items/week); n = 4445, and Infrequent Can Users (≤2 canned items/week); n = 2732. The results provide evidence that Frequent Can Users consume more nutrient-dense food groups such as fruits, vegetables, dairy products, and protein-rich foods, and also have higher intakes of 17 essential nutrients including the shortfall nutrients-potassium, calcium and fiber-when compared to Infrequent Can Users. Therefore, in addition to fresh foods, diets higher in nutrient-dense canned food consumption can also offer dietary options which improve nutrient intakes and the overall diet quality of Americans.

  14. Frequent Canned Food Use is Positively Associated with Nutrient-Dense Food Group Consumption and Higher Nutrient Intakes in US Children and Adults

    PubMed Central

    Comerford, Kevin B.

    2015-01-01

    In addition to fresh foods, many canned foods also provide nutrient-dense dietary options, often at a lower price, with longer storage potential. The aim of this study was to compare nutrient-dense food group intake and nutrient intake between different levels of canned food consumption in the US. Consumption data were collected for this cross-sectional study from 9761 American canned food consumers (aged two years and older) from The NPD Group’s National Eating Trends® (NET®) database during 2011–2013; and the data were assessed using The NPD Group’s Nutrient Intake Database. Canned food consumers were placed into three groups: Frequent Can Users (≥6 canned items/week); n = 2584, Average Can Users (3–5 canned items/week); n = 4445, and Infrequent Can Users (≤2 canned items/week); n = 2732. The results provide evidence that Frequent Can Users consume more nutrient-dense food groups such as fruits, vegetables, dairy products, and protein-rich foods, and also have higher intakes of 17 essential nutrients including the shortfall nutrients—potassium, calcium and fiber—when compared to Infrequent Can Users. Therefore, in addition to fresh foods, diets higher in nutrient-dense canned food consumption can also offer dietary options which improve nutrient intakes and the overall diet quality of Americans. PMID:26184294

  15. Qualitative Analysis of Nutrient-Phytoplankton Models

    NASA Astrophysics Data System (ADS)

    Cai, Qinghua; Mohamad, Zakaria; Yuan, Yuan

    2011-11-01

    We propose two nutrient-phytoplankton models with instantaneous and time delayed recyclings, investigate the dynamics and examine the responses to model complexities. We use geometrical and analytical methods to discuss the existence and stability of the possible steady state solutions and study the occurrence of Hopf bifurcation. Numerical simulations illustrate the analytical results and provide further insight into the dynamics of the model, biological interpretations are given.

  16. ATMOSPHERIC DEPOSITION MODELING AND MONITORING OF NUTRIENTS

    EPA Science Inventory

    This talk presents an overview of the capabilities and roles that regional atmospheric deposition models can play with respect to multi-media environmental problems. The focus is on nutrient deposition (nitrogen). Atmospheric deposition of nitrogen is an important contributor to...

  17. Nutrient Models Developments Using Runoff-Nutrient Relationships in an Agricultural Prairie Basin, Manitoba.

    NASA Astrophysics Data System (ADS)

    Mahmood, T. H.; Pomeroy, J. W.; Wheater, H. S.; Elliott, J. A.; Baulch, H. M.; Lindenschmidt, K. E.

    2015-12-01

    Nutrient export to streams and lakes from agricultural activities can result in significant deterioration of water quality and aquatic ecosystem health. In Western Canada, particular concerns arise for prairie agricultural systems, which are dominated by the effects of a cold climate. Insufficient attention has been given to understand the links between cold region watershed responses and nutrient concentration and a robust watershed-scale modeling framework is needed to simulate nutrient concentration and loads. Long-term, field observations of nutrient concentration-runoff relationships were used to develop nutrient concentration models for the Tobacco Creek Model Watershed (TCMW) which drains into the Red River basin. Field observations include streamflow concentrations of N and P at multiple scales from two headwater basins. Distinct nutrient concentration-runoff models for snowmelt, rain on snow (ROS) and rainfall runoff processes were developed from observed runoff-nutrient concentration relationships. Snowmelt runoff had a moderately positive correlation with particulate nutrient concentrations but no correlation with that of dissolved nutrients. ROS runoff had a weak relationship with both particulate and dissolved nutrient concentrations. Rainfall runoff had the strongest positive correlation with particulate nutrient concentrations but no association with that of dissolved nutrients. The modeling approach also identified a clear hysteretic behavior in the relationship between runoff and particulate nutrient concentration during the 2013 snowmelt runoff event at the basin outlet gauge. The models provide insight into the hydrological controls on nutrient export from cold regions watersheds and the strong effects of inter-annual climatic variability. Snowmelt runoff is a reliable exporter of large nutrient loads while nutrient export by rainfall runoff exceeded snowmelt runoff during hydrologically wet summers such as 2002, 2005, 2011 and 2013.

  18. Lactose intolerance and African Americans: implications for the consumption of appropriate intake levels of key nutrients.

    PubMed

    2009-10-01

    Lactose intolerance is a complex condition that is complicated by cultural beliefs and perceptions about the consumption of dairy products. These attitudes about dairy may contribute to inadequate intake of key nutrients that may impact conditions that contribute to health disparities in African Americans. While a complex health problem, lactose intolerance is easy to treat. However, no treatment can improve the body's ability to produce lactase. Yet, symptoms can be controlled through dietary strategies. This position paper emphasizes the importance of using patient and provider-level strategies in order to reduce the risks to the health of African Americans that may accrue as a result of dairy nutrient deficiency. Evaluation and assessment of interventions tested is critical so that evidence-based approaches to addressing dairy nutrient deficiency and lactose Intolerance can be created. Lastly, it is essential for physicians to communicate key messages to their patients. Since dairy nutrients address important health concerns, the amelioration of lactose intolerance is an investment in health. Lactose intolerance is common, is easy to treat, and can be managed. It is possible to consume dairy even in the face of a history of maldigestion or lactose intolerant issues. Gradually increasing lactose in the diet--drinking small milk portions with food, eating yogurt, and consuming cheese--are effective strategies for managing lactose intolerance and meeting optimal dairy needs.

  19. Lactose intolerance and African Americans: implications for the consumption of appropriate intake levels of key nutrients.

    PubMed

    2009-10-01

    Lactose intolerance is a complex condition that is complicated by cultural beliefs and perceptions about the consumption of dairy products. These attitudes about dairy may contribute to inadequate intake of key nutrients that may impact conditions that contribute to health disparities in African Americans. While a complex health problem, lactose intolerance is easy to treat. However, no treatment can improve the body's ability to produce lactase. Yet, symptoms can be controlled through dietary strategies. This position paper emphasizes the importance of using patient and provider-level strategies in order to reduce the risks to the health of African Americans that may accrue as a result of dairy nutrient deficiency. Evaluation and assessment of interventions tested is critical so that evidence-based approaches to addressing dairy nutrient deficiency and lactose Intolerance can be created. Lastly, it is essential for physicians to communicate key messages to their patients. Since dairy nutrients address important health concerns, the amelioration of lactose intolerance is an investment in health. Lactose intolerance is common, is easy to treat, and can be managed. It is possible to consume dairy even in the face of a history of maldigestion or lactose intolerant issues. Gradually increasing lactose in the diet--drinking small milk portions with food, eating yogurt, and consuming cheese--are effective strategies for managing lactose intolerance and meeting optimal dairy needs. PMID:19899495

  20. Dynamic shear-stress-enhanced rates of nutrient consumption in gas-liquid semi-continuous-flow suspensions

    NASA Astrophysics Data System (ADS)

    Belfiore, Laurence A.; Volpato, Fabio Z.; Paulino, Alexandre T.; Belfiore, Carol J.

    2011-12-01

    The primary objective of this investigation is to establish guidelines for generating significant mammalian cell density in suspension bioreactors when stress-sensitive kinetics enhance the rate of nutrient consumption. Ultra-low-frequency dynamic modulations of the impeller (i.e., 35104 Hz) introduce time-dependent oscillatory shear into this transient analysis of cell proliferation under semi-continuous creeping flow conditions. Greater nutrient consumption is predicted when the amplitude A of modulated impeller rotation increases, and stress-kinetic contributions to nutrient consumption rates increase linearly at higher modulation frequency via an application of fluctuation-dissipation response. Interphase mass transfer is required to replace dissolved oxygen as it is consumed by aerobic nutrient consumption in the liquid phase. The theory and predictions described herein could be important at small length scales in the creeping flow regime where viscous shear is significant at the interface between the nutrient medium and isolated cells in suspension. Two-dimensional flow around spherically shaped mammalian cells, suspended in a Newtonian culture medium, is analyzed to calculate the surface-averaged magnitude of the velocity gradient tensor and modify homogeneous rates of nutrient consumption that are stimulated by viscous shear, via the formalism of stress-kinetic reciprocal relations that obey Curie's theorem in non-equilibrium thermodynamics. Time constants for stress-free free and stress-sensitive stress nutrient consumption are defined and quantified to identify the threshold (i.e., stress,threshold) below which the effect of stress cannot be neglected in accurate predictions of bioreactor performance. Parametric studies reveal that the threshold time constant for stress-sensitive nutrient consumption stress,threshold decreases when the time constant for stress

  1. Factors influencing consumption of nutrient rich forest foods in rural Cameroon.

    PubMed

    Fungo, Robert; Muyonga, John H; Kabahenda, Margaret; Okia, Clement A; Snook, Laura

    2016-02-01

    Studies show that a number of forest foods consumed in Cameroon are highly nutritious and rich in health boosting bioactive compounds. This study assessed the knowledge and perceptions towards the nutritional and health promoting properties of forest foods among forest dependent communities. The relationship between knowledge, perceptions and socio-demographic attributes on consumption of forest foods was also determined. A total of 279 females in charge of decision making with respect to food preparation were randomly selected from 12 villages in southern and eastern Cameroon and interviewed using researcher administered questionnaires. Multivariate logistic regression analysis was used to identify the factors affecting consumption of forest foods. Baillonella toxisperma (98%) and Irvingia gabonesis (81%) were the most known nutrient rich forest foods by the respondents. About 31% of the respondents were aware of the nutritional value and health benefits of forest foods. About 10%-61% of the respondents expressed positive attitudes to questions related with health benefits of specific forest foods. Consumption of forest foods was found to be higher among polygamous families and also positively related to length of stay in the forest area and age of respondent with consumption of forest foods. Education had an inverse relationship with use of forest foods. Knowledge and positive attitude towards the nutritional value of forest foods were also found to positively influence consumption of forest foods. Since knowledge was found to influence attitude and consumption, there is need to invest in awareness campaigns to strengthen the current knowledge levels among the study population. This should positively influence the attitudes and perceptions towards increased consumption of forest foods.

  2. Modeling Addictive Consumption as an Infectious Disease*

    PubMed Central

    Alamar, Benjamin; Glantz, Stanton A.

    2011-01-01

    The dominant model of addictive consumption in economics is the theory of rational addiction. The addict in this model chooses how much they are going to consume based upon their level of addiction (past consumption), the current benefits and all future costs. Several empirical studies of cigarette sales and price data have found a correlation between future prices and consumption and current consumption. These studies have argued that the correlation validates the rational addiction model and invalidates any model in which future consumption is not considered. An alternative to the rational addiction model is one in which addiction spreads through a population as if it were an infectious disease, as supported by the large body of empirical research of addictive behaviors. In this model an individual's probability of becoming addicted to a substance is linked to the behavior of their parents, friends and society. In the infectious disease model current consumption is based only on the level of addiction and current costs. Price and consumption data from a simulation of the infectious disease model showed a qualitative match to the results of the rational addiction model. The infectious disease model can explain all of the theoretical results of the rational addiction model with the addition of explaining initial consumption of the addictive good. PMID:21339848

  3. Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients.

    PubMed

    Smith, Matthew R; Micha, Renata; Golden, Christopher D; Mozaffarian, Dariush; Myers, Samuel S

    2016-01-01

    Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model--the Global Expanded Nutrient Supply (GENuS) model--to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent

  4. Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients.

    PubMed

    Smith, Matthew R; Micha, Renata; Golden, Christopher D; Mozaffarian, Dariush; Myers, Samuel S

    2016-01-01

    Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model--the Global Expanded Nutrient Supply (GENuS) model--to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent

  5. A study of snack consumption, night-eating habits, and nutrient intake in gestational diabetes mellitus.

    PubMed

    Park, Hee-Jin; Lee, Jinju; Kim, Ji-Myung; Lee, Hyun Ah; Kim, Sung-Hoon; Kim, Yuri

    2013-01-01

    This study was performed to identify dietary behavior such as snack consumption, night-eating and nutrients intake associated with gestational diabetes mellitus (GDM). The study was conducted on 219 normal glucose tolerance (NGT) subjects and 44 GDM subjects by using a questionnaire including dietary behavior, food frequency and 3-day food record. The mean age, OGTT, and delivery weight of GDM subjects were statistically higher than those in NGT. A larger proportion of NGT subjects consumed black coffee (49.8%) while the majority of GDM subjects (61.4%) drank mixed coffee with sugar and cream. Dairy products were the most frequently consumed snack item in NGT subjects (40.7%), while fruits were most frequently consumed food item in GDM subjects (34.4%). Many of NGT subjects (49.8%) answered that they hardly took night-eating snacks whereas most of GDM subjects (61.4%) took night-eating snacks more than once a week. For change of taste preference, the proportion of NGT subjects who showed less preference for salty taste (33.3%) or greasy taste (16.9%) was higher than that of GDM subjects (11.4%). Nutrient intakes of energy, fat, cholesterol, saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), carbohydrate, vitamin B(1), vitamin B(2), vitamin C, and vitamin E in GDM group were significantly higher than those in NGT group. Nutrient densities of SFA and vitamin C in GDM group were higher and nutrient density of calcium was lower than those in NGT group. Taken together, it is recommended to reduce night-eating snack and choose less salty and fatty foods, black-coffee rather than coffee with cream and sugar, and more dairy products to prevent GDM.

  6. Unravelling trophic subsidies of agroecosystems for biodiversity conservation: food consumption and nutrient recycling by waterbirds in Mediterranean rice fields.

    PubMed

    Navedo, Juan G; Hahn, Steffen; Parejo, Manuel; Abad-Gómez, José M; Gutiérrez, Jorge S; Villegas, Auxiliadora; Sánchez-Guzmán, Juan M; Masero, José A

    2015-04-01

    Waterbirds can reallocate a considerable amount of nutrients within agricultural fields and between agriculture sites and wetlands. However their effects on biogeochemical cycles have rarely been quantified. We estimated bird numbers, diet (from stable isotope analysis), food supply, and the food consumption on rice fields by overwintering waterbirds in one of the most important areas for rice production in southwestern Europe and a key area for various migrating and resident waterbird species. Herein, we modelled the nutrient (N and P) recycling in rice fields, and their transport to reservoirs. The energy consumption by waterbirds (96,605±18,311 individuals) on rice fields during winter averaged at 89.9±39.0 kJ·m(-2), with its majority (89.9%) belonging to foraging on rice seeds. Thus, the birds removed about 26% of rice seeds leftover after harvest (estimated in 932.5±504.7 seeds·m(-2) in early winter) wherein common cranes and dabbling ducks (four species) were the most important consumers. Waterbirds foraging and roosting in the rice fields recycled more than 24.1 (1.0 kg·ha(-1)) of N and an additional 5.0 tons (0.2 kg·ha(-1)) of P in the Extremadura's rice fields during winter. Additionally, we estimated that 2.3 tons of N and 550 kg of P were removed from rice fields and transported to reservoirs. The seasonal foraging of wildlife should result in a direct benefit for rice farmers by improving nutrient recycling through defecation by waterbirds with respect to artificial fertilisation. Additionally, rice fields located in the cranes' core wintering areas can provide sufficient food supply to induce habitat shift from their traditional wintering habitat in 'dehesas' to rice fields, which causes indirect socioeconomic benefit through reduced acorn consumption by cranes. Our modelling approach may thus be especially helpful for management decisions regarding rice agroecosystems in areas which are also important for the conservation of migratory

  7. Unravelling trophic subsidies of agroecosystems for biodiversity conservation: food consumption and nutrient recycling by waterbirds in Mediterranean rice fields.

    PubMed

    Navedo, Juan G; Hahn, Steffen; Parejo, Manuel; Abad-Gómez, José M; Gutiérrez, Jorge S; Villegas, Auxiliadora; Sánchez-Guzmán, Juan M; Masero, José A

    2015-04-01

    Waterbirds can reallocate a considerable amount of nutrients within agricultural fields and between agriculture sites and wetlands. However their effects on biogeochemical cycles have rarely been quantified. We estimated bird numbers, diet (from stable isotope analysis), food supply, and the food consumption on rice fields by overwintering waterbirds in one of the most important areas for rice production in southwestern Europe and a key area for various migrating and resident waterbird species. Herein, we modelled the nutrient (N and P) recycling in rice fields, and their transport to reservoirs. The energy consumption by waterbirds (96,605±18,311 individuals) on rice fields during winter averaged at 89.9±39.0 kJ·m(-2), with its majority (89.9%) belonging to foraging on rice seeds. Thus, the birds removed about 26% of rice seeds leftover after harvest (estimated in 932.5±504.7 seeds·m(-2) in early winter) wherein common cranes and dabbling ducks (four species) were the most important consumers. Waterbirds foraging and roosting in the rice fields recycled more than 24.1 (1.0 kg·ha(-1)) of N and an additional 5.0 tons (0.2 kg·ha(-1)) of P in the Extremadura's rice fields during winter. Additionally, we estimated that 2.3 tons of N and 550 kg of P were removed from rice fields and transported to reservoirs. The seasonal foraging of wildlife should result in a direct benefit for rice farmers by improving nutrient recycling through defecation by waterbirds with respect to artificial fertilisation. Additionally, rice fields located in the cranes' core wintering areas can provide sufficient food supply to induce habitat shift from their traditional wintering habitat in 'dehesas' to rice fields, which causes indirect socioeconomic benefit through reduced acorn consumption by cranes. Our modelling approach may thus be especially helpful for management decisions regarding rice agroecosystems in areas which are also important for the conservation of migratory

  8. Plain Water and Sugar-Sweetened Beverage Consumption in Relation to Energy and Nutrient Intake at Full-Service Restaurants

    PubMed Central

    An, Ruopeng

    2016-01-01

    Background: Drinking plain water, such as tap or bottled water, provides hydration and satiety without adding calories. We examined plain water and sugar-sweetened beverage (SSB) consumption in relation to energy and nutrient intake at full-service restaurants. Methods: Data came from the 2005–2012 National Health and Nutrition Examination Survey, comprising a nationally-representative sample of 2900 adults who reported full-service restaurant consumption in 24-h dietary recalls. Linear regressions were performed to examine the differences in daily energy and nutrient intake at full-service restaurants by plain water and SSB consumption status, adjusting for individual characteristics and sampling design. Results: Over 18% of U.S. adults had full-service restaurant consumption on any given day. Among full-service restaurant consumers, 16.7% consumed SSBs, 2.6% consumed plain water but no SSBs, and the remaining 80.7% consumed neither beverage at the restaurant. Compared to onsite SSB consumption, plain water but no SSB consumption was associated with reduced daily total energy intake at full-service restaurants by 443.4 kcal, added sugar intake by 58.2 g, saturated fat intake by 4.4 g, and sodium intake by 616.8 mg, respectively. Conclusion: Replacing SSBs with plain water consumption could be an effective strategy to balance energy/nutrient intake and prevent overconsumption at full-service restaurant setting. PMID:27153083

  9. Nutrient-contaminant (Pu) plant accumulation model

    SciTech Connect

    Cowan, C.E.; Jenne, E.A.; Simpson, J.C.; Cataldo, D.A.

    1981-12-01

    A model was developed which simulates the movement and daily accumulation of nutrients and contaminants in crop plants resulting from known physiological processes in the plant. In the model, the daily contaminant accumulation is governed by daily increase in plant biomass derived from photosynthesis and by the specified thermodynamic activity of the bioavailable contaminant species in soil or hydroponic solutin. Total accumulation and resulting concentration in the plant's root, stem and branch, leaf, and reproductive compartments can be simulated any time during the growing season. Parameters were estimated from data on plutonium accumulation in soybeans and the model was calibrated against this same data set. The plutonium distribution in the plant was found to be most sensitive to parameters related to leaf accumulation. Contamination at different times during the growing season resulted in a large change in predicted leaf accumulation but very little change in predicted accumulation in other plant parts except when contamination occurred very late in the growing season.

  10. Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients

    PubMed Central

    Golden, Christopher D.; Mozaffarian, Dariush

    2016-01-01

    Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model—the Global Expanded Nutrient Supply (GENuS) model—to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961–2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent

  11. Hardwood seeding root and nutrient parameters for a model of nutrient uptake.

    PubMed

    Kelly, J M; Scarbrough, J D; Mays, P A

    2001-01-01

    Use of mechanistic models is an increasingly accepted way to evaluate complex processes. The Barber-Cushman model provides a means to simulate nutrient uptake once information on root system characteristics, nutrient uptake, and soil nutrient supply are developed. Objectives of this study were to determine during a growing season: (i) root growth for 1-yr-old black cherry (Prunus serotina Ehrh.), northern red oak (Quercus rubra L.), and red maple (Acer rubrum L.) seedlings; (ii) net plant increase in N, P, K, Ca, and Mg; (iii) soil solution and solid phase nutrient concentrations; and (iv) the influence of root growth and soil nutrient supply changes on nutrient uptake using the Barber-Cushman model. Seedlings were grown in pots containing A horizon soil from two forest sites. Measurements were made on five occasions during the growing season. Root growth averaged 41.5 cm d-1 for red maple compared with 28.0 and 16.7 cm d-1 for cherry and oak, respectively. Seventy-five percent of root growth occurred at the end of the growing season. Total plant N showed the greatest change (25-58%) due to soil source. Model simulations underestimated observed uptake by 31 to 99%. A clear relationship between soil solution nutrient concentration and plant uptake, an important assumption of the model, was not observed. Results indicate care will need to be exercised in the development and use of root growth and nutrient supply values in mechanistic models. PMID:11285903

  12. Modeling the Response of Nutrient Concentrations and Primary Productivity in Lake Michigan to Nutrient Loading Scenarios

    EPA Science Inventory

    A water quality model, LM3 Eutro, will be used to estimate the response of nutrient concentrations and primary productivity in Lake Michigan to nutrient loading scenarios. This work is part of a larger effort, the Future Midwestern landscapes study, that will estimate the produc...

  13. Meeting and exceeding dairy recommendations: effects of dairy consumption on nutrient intakes and risk of chronic disease.

    PubMed

    Rice, Beth H; Quann, Erin E; Miller, Gregory D

    2013-04-01

    The 2010 Dietary Guidelines for Americans indicate the US population is experiencing an epidemic of overweight and obesity while maintaining a nutrient-poor, energy-dense diet associated with an increased risk of osteoarthritis, cardiovascular disease, and type 2 diabetes. To build upon the review of published research in the Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010, this article aims to review the scientific literature pertaining to the consumption of dairy foods and the effects of dairy consumption on nutrient intakes and chronic disease risk published between June 2010, when the report was released, and September 2011. PubMed was searched for articles using the following key words: dairy, milk, nutrient intake, bone health, body composition, cardiovascular disease, type 2 diabetes, and blood pressure. Evidence indicates that increasing dairy consumption to the recommended amount, i.e., three servings daily for individuals ≥9 years of age, helps close gaps between current nutrient intakes and recommendations. Consuming more than three servings of dairy per day leads to better nutrient status and improved bone health and is associated with lower blood pressure and reduced risk of cardiovascular disease and type 2 diabetes.

  14. Long Term Trends in Subantarctic Nutrient Consumption: Evidence from Sedimentary and Diatom-Bound Nitrogen Isotopes

    NASA Astrophysics Data System (ADS)

    Bedsole, P.

    2014-12-01

    It has been proposed that the long term increase in Subantarctic opal export during glacial periods, centered around 1 Ma, is related to enhanced iron deposition and, potentially, carbon dioxide drawdown. New bulk sedimentary and diatom-bound nitrogen isotope records are used in combination with opal accumulation data from ODP Site 1090 to investigate controls on export production over the last 3 Ma. Sedimentary nitrogen content tracks opal during periods of high iron accumulation, especially after ~1 Ma. Bulk sedimentary nitrogen isotope trends are negatively correlated with sedimentary N-content and opal accumulation. This may be signal weaker nutrient consumption during times of high production, perhaps as a result of enhanced vertical nutrient supply. Alternatively, this variation in bulk, where high values occur in organic poor intervals, is consistent with other evidence for nitrogen isotopic alteration during periods of low export to the seafloor. The diatom-bound nitrogen isotope record does not have a clear relationship with opal or iron accumulation. A long term shift in the diatom-bound N isotope values is apparent, where the average diatom-bound δ15N from 0.5-1 Ma is 4.4 ‰, and from 2-2.6 Ma is 5.9 ‰. This decrease may reflect long-term changes in nitrate availability. A first order comparison to planktonic/benthic carbon isotopic gradients suggests that enhanced vertical mixing may explain the observed productivity peaks and lower overall diatom-bound N isotope values in the interval centered around 1 Ma.

  15. Modelling nutrient reduction targets - model structure complexity vs. data availability

    NASA Astrophysics Data System (ADS)

    Capell, Rene; Lausten Hansen, Anne; Donnelly, Chantal; Refsgaard, Jens Christian; Arheimer, Berit

    2015-04-01

    In most parts of Europe, macronutrient concentrations and loads in surface water are currently affected by human land use and land management choices. Moreover, current macronutrient concentration and load levels often violate European Water Framework Directive (WFD) targets and effective measures to reduce these levels are sought after by water managers. Identifying such effective measures in specific target catchments should consider the four key processes release, transport, retention, and removal, and thus physical catchment characteristics as e.g. soils and geomorphology, but also management data such as crop distribution and fertilizer application regimes. The BONUS funded research project Soils2Sea evaluates new, differentiated regulation strategies to cost-efficiently reduce nutrient loads to the Baltic Sea based on new knowledge of nutrient transport and retention processes between soils and the coast. Within the Soils2Sea framework, we here examine the capability of two integrated hydrological and nutrient transfer models, HYPE and Mike SHE, to model runoff and nitrate flux responses in the 100 km2 Norsminde catchment, Denmark, comparing different model structures and data bases. We focus on comparing modelled nitrate reductions within and below the root zone, and evaluate model performances as function of available model structures (process representation within the model) and available data bases (temporal forcing data and spatial information). This model evaluation is performed to aid in the development of model tools which will be used to estimate the effect of new nutrient reduction measures on the catchment to regional scale, where available data - both climate forcing and land management - typically are increasingly limited with the targeted spatial scale and may act as a bottleneck for process conceptualizations and thus the value of a model as tool to provide decision support for differentiated regulation strategies.

  16. Kootenai River Nutrient Dosing System and N-P Consumption: Year 2008.

    SciTech Connect

    Holderman, Charles

    2009-02-19

    In early 2006 we designed and built low energy consumption, pump-operated system, for dosing of the liquid nutrient in the summer 2006 season. This operated successfully, and the system was used again during the 2007 and 2008 seasons for dosing. During the early winter period, 2008, laboratory tests were made of the liquid nutrient pump system, and it was noted that small amounts of air were being entrained on the suction side of the pump, during conditions when the inlet pressure was low. It was believed that this was the cause of diurnal fluctuations in the flow supplied, characteristic of the 2007 year flow data. Replacement of '0' rings on the inlet side of the pumps was the solution to this problem, and when tested in the field during the summer season, the flow supplied was found to be stable. A decision was made by the IKERT committee at the meeting of 20th to 21st May 2008 (held in Coeur d'Alene, Idaho) to use an injection flow rate of liquid fertilizer (polyammonium phosphate 10-34-0) to achieve a target phosphorus concentration of 3.0 {micro}g/L, after complete mixing in the river. This target concentration was the same as that used in 2006 and 2007. The proposed starting date was as early as possible in June 2008. Plans were made to measure the dosing flow in three ways. Two of the three methods of flow measurement (1 and 2 below) are inter-dependent. These were: (1) Direct measurement of flow rate by diverting dosing flow into a 1000 mL volume standard flask. The flow rate was computed by dividing the flask volume by the time required to fill the flask. This was done a few times only during the summer period. (2) Adjusting the flow rate reading of the Gamma dosing pump using the 'calibration' function to achieve agreement with the flow rate computed by method 1 above. (3) Direct measurement by electrical signal from conductive fluid passing through a magnetic field (Seametrics meter, as used in previous years). Values were recorded every 4 minutes by a

  17. NUTRIENTS IN WATERSHEDS: DEVELOPING ENHANCED MODELING TOOLS

    EPA Science Inventory

    Nutrient enrichment is one of the most important stressors causing water-resource impairment. These impairments are causing devastating changes: 1) high nitrate concentrations have rendered the groundwaters and reservoirs in many regions impotable -- especially in the rural area...

  18. Effects of nutrient enrichment on channel catfish growth and consumption in Mount Storm Lake, West Virginia

    USGS Publications Warehouse

    Blanc, T.J.; Margraf, F.J.

    2002-01-01

    With the objective of augmenting fish production in Mount Storm Lake, Virginia Electric and Power Company initiated a programme of phosphorus addition to increase primary production, and ultimately, channel catfish (Ictaturus punctatus) growth in the 486 ha cooling reservoir. We simulated channel catfish growth dynamics using two bioenergetics modelling scenarios: (i) effects of average reservoir temperature on growth, conversion efficiency and consumption; and (ii) effects of reservoir enrichment on growth, which is simulated by increasing feeding rates. During 1991-1993, fish were sampled monthly, but sampling was increased to every 2 weeks during the peak growing season (June-September). Most of the channel catfish collected were aged 0 year and aged 1 year with rapid annual growth rates ranging from 9.0 to 13.7 J/g. We found many age 1 250-300 mm catfish, but few beyond this size. Conversion efficiency (joules gained/joules consumed) was low at approximately 18-19%. High algae consumption (40%) was evident, but consumption of zooplankton and Asiatic clam (Corbicula sp.) increased over the study. Simulated increased feeding rates showed that channel catfish were food limited in summer and fall (July-December). Weight gains with 5 and 10% feeding increases were 6-13% and 18-38%, respectively, from the baseline. Catfish of all sizes should benefit from phosphorus additions.

  19. Nutrients and Chemical Pollutants in Fish and Shellfish. Balancing Health Benefits and Risks of Regular Fish Consumption.

    PubMed

    Domingo, José L

    2016-01-01

    Dietary patterns and lifestyle factors are clearly associated with at least five of the ten leading causes of death, including coronary heart disease, certain types of cancer, stroke, non-insulin insulin-dependent diabetes mellitus, and atherosclerosis. Concerning specifically fish and seafood consumption, its beneficial health effects in humans are clearly supported by an important number of studies performed in the last 30 years. These studies have repeatedly linked fish consumption, especially those species whose contents in omega-3 fatty acids are high, with healthier hearts in the aging population. The nutritional benefits of fish and seafood are also due to the content of high-quality protein, vitamins, as well as other essential nutrients. However, a number of studies, particularly investigations performed in recent years, have shown that the unavoidable presence of environmental contaminants in fish and shellfish can also mean a certain risk for the health of some consumers. While prestigious international associations as the American Heart Association have recommended eating fish at least two times (two servings a week), based on our own experimental results, as well as in results from other laboratories, we cannot be in total agreement with that recommendation. Although a regular consumption of most fish and shellfish species should not mean adverse health effects for the consumers, the specific fish and shellfish species consumed, the frequency of consumption, as well as the meal size, are essential issues for adequately balancing the health benefits and risks of regular fish consumption.

  20. Assessment of the nutritional status of children with special needs in Alexandria: I. Nutrient intake and food consumption.

    PubMed

    Shabayek, Magda M

    2004-01-01

    The present study was undertaken to evaluate the nutritional status of children with special needs in Alexandria city, on the basis of nutrient intake and food consumption. Socio-demographic characteristics and dietary data were determined in a sample of 231 disabled children chosen randomly from five specialized day care centers. Results showed that the age of the sample ranged from less than 7 to 24 years with a mean age of 12.6 +/- 4.7 years. Mental retardation represents the highest proportion of subjects followed by Down's syndrome and then Autism Male subjects were found to consume higher nutrients than females at all ages except age under seven years. The intake of both gender was less than the recommended for energy, calcium, vitamin A, niacin and zinc. While the intake of protein and vitamin C was more than the RDA Iron intake was below the recommended for females at all ages and within the acceptable level for male. The results also showed that there is a relationship between nutrient intake and disability type. Down syndrome children were found to consume more nutrients than mentally retarded and autistic subjects.

  1. Mathematical modelling of plant water and nutrient uptake

    NASA Astrophysics Data System (ADS)

    Roose, Tiina

    2010-05-01

    In this presentation I will describe a model of plant water and nutrient uptake and how to translate this model and experimental data from the single root scale to the root branching structure scale. The model starts at the single root scale and describes the water and nutrient movement in the soil using Richards' equation (water uptake) and diffusion-convection equation (nutrient uptake). The water and nutrient uptake in the single root scale model is represented by boundary conditions. In the case of nutrient uptake this has the form of a non-linear Michaelis-Menten uptake law and in the case of water this is given by a soil-xylem pressure difference boundary condition. The flow of water in the xylem is modeled as Poiseuille flow. We solve the single root scale models using the analytic approximate technique of asymptotic expansions similar to Oseen expansions known from fluid dynamics. We will then discuss how to use the analytic expression to estimate the water and nutrient uptake by growing root branching systems. We model the growth of the root system using a dynamic population model to describe the branching and elongation of roots in the branching system. This root branching population model results in a hyperbolic equation similar to age dependent population models and it can be solved fully analytically using the method of characteristics. Thus we have a fully analytic description of the root branching system evolution. We use this branching model to estimate the nutrient uptake in a scenario when the competition between subbranches is small, i.e., as it is in the case of phosphate, potassium and arsenic. We compare our approximate analytic model to a full 3d simulation of the root system phosphate uptake and find that the analytic model almost perfectly reproduces the 3d numerical model. In addition the analytic model can be included in larger field/catchment/climate scale models something which is not practically possible with the numerical simulations

  2. A global model of carbon-nutrient interactions

    NASA Technical Reports Server (NTRS)

    Moore, Berrien, III; Gildea, Patricia; Vorosmarty, Charles; Mellilo, Jerry M.; Peterson, Bruce J.

    1985-01-01

    The global biogeochemical model presented has two primary objectives. First, it characterizes natural elemental cycles and their linkages for the four elements significant to Earth's biota: C, N, S, and P. Second, it describes changes in these cycles due to human activity. Global nutrient cycles were studied within the drainage basins of several major world rivers on each continent. The initial study region was the Mississippi drainage basin, concentrating on carbon and nitrogen. The model first establishes the nutrient budgets of the undisturbed ecosystems in a study region. It then uses a data set of land use histories for that region to document the changes in these budgets due to land uses. Nutrient movement was followed over time (1800 to 1980) for 30 ecosystems and 10 land use categories. A geographically referenced ecological information system (GREIS) was developed to manage the digital global data bases of 0.5 x 0.5 grid cells needed to run the model: potential vegetation, drainage basins, precipitation, runoff, contemporary land cover, and FAO soil maps of the world. The results show the contributions of land use categories to river nutrient loads on a continental scale; shifts in nutrient cycling patterns from closed, steady state systems to mobile transient or open, steady state systems; soil organic matter depletion patterns in U.S. agricultural lands; changing nutrient ratios due to land use changes; and the effect of using heavy fertilizer on aquatic systems.

  3. Tree nut consumption improves nutrient intake and diet quality in US adults: an analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent epidemiologic studies assessing tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts) consumption and the association with nutrient intake and diet quality are lacking. This study determined the association of tree nut consumption and ...

  4. Modelling nutrient emissions and the impact of nutrient reduction measures in the Weser river basin, Germany.

    PubMed

    Hirt, Ulrike; Venohr, Markus; Kreins, Peter; Behrendt, Horst

    2008-01-01

    To implement the European Water Framework Directive (WFD) into German law, measures have to be taken to reduce the unacceptably high nutrient input into rivers. To identify the most effective measures, the sources and pathways of nutrient emissions into rivers have to be quantified. Therefore, the MONERIS model is applied, which quantifies nutrients emissions into river basins, via various point and diffuse pathways, as well as nutrient load in rivers. Most nitrogen emissions come from groundwater flow (43%), tile drainages (30%), and point sources (12%), whereas most phosphorus emissions come from groundwater flow (31%), point sources (23%), erosion (13%) and overland flow (12%). Because of their great distance from the river basin outlet, the southern sub-basins Werra and Fulda-Diemel have an 8% reduction in their nitrogen loads and a 15% and 16% reduction in their phosphorus loads, respectively. This reduction is due to retention in the main part of the river Weser. For the choice of the most effective measures, the different retention in the river is relevant.

  5. EFFECTS OF CONSUMPTION OF BEEF CUTS ON NUTRIENT INTAKE IN AMERICANS IN NHANES 1999-2002

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 2005 Dietary Guidelines report identifies the meat group as a contributor of 13 nutrients: major (protein, niacin, vitamin B6, and zinc) or substantial (K, P, Mg, Fe, Cu, vitamins B1, B2, B12, and E). However, the specific contribution of beef to the American diet has not yet been determined. W...

  6. Consumption of Mass Communication--Construction of a Model on Information Consumption Behaviour.

    ERIC Educational Resources Information Center

    Sepstrup, Preben

    A general conceptual model on the consumption of information is introduced. Information as the output of the mass media is treated as a product, and a model on the consumption of this product is developed by merging elements from consumer behavior theory and mass communication theory. Chapter I gives basic assumptions about the individual and the…

  7. Benthic nutrient fluxes and sediment oxygen consumption in a full-scale facultative pond in Patagonia, Argentina.

    PubMed

    Faleschini, M; Esteves, J L

    2013-01-01

    The study of benthic metabolism is an interesting tool to understand the process that occurs in bottom water at wastewater stabilization ponds. Here, rates of benthic oxygen consumption and nutrient exchange across the water-sludge interface were measured in situ using a benthic chamber. The research was carried out during autumn, winter, and summer at a municipal facultative stabilization pond working in a temperate region (Puerto Madryn city, Argentina). Both a site near the raw wastewater inlet (Inlet station) and a site near the outlet (Outlet station) were sampled. Important seasonal and spatial patterns were identified as being related to benthic fluxes. Ammonium release ranged from undetectable (autumn/summer - Inlet station) to +30.7 kg-NH4(+) ha(-1) d(-1) (autumn - Outlet station), denitrification ranged from undetectable (winter - in both sites) to -4.0 kg-NO3(-) ha(-1) d(-1) (autumn - Outlet station), and oxygen consumption ranged from 0.07 kg-O2ha(-1) d(-1) (autumn/summer - Outlet station) to 0.84 kg-O2ha(-1) d(-1) (autumn - Inlet station). During the warmer months, the mineralization of organic matter from the bottom pond acts as a source of nutrients, which seem to support the important development of phytoplankton and nitrification activity recorded in the surface water. Bottom processes could be related to the advanced degree and efficiency of the treatment, the temperature, and probably the strong and frequent wind present in the region.

  8. Modelling macrofaunal biomass in relation to hypoxia and nutrient loading

    NASA Astrophysics Data System (ADS)

    Timmermann, Karen; Norkko, Joanna; Janas, Urszula; Norkko, Alf; Gustafsson, Bo G.; Bonsdorff, Erik

    2012-12-01

    Nutrient loading of aquatic ecosystems results in more food for benthic macrofaunal communities but also increases the risk of hypoxia, resulting in a reduction or complete loss of benthic biomass. This study investigates the interaction between eutrophication, hypoxia and benthic biomass with emphasis on the balance between gains and loss of benthic biomass due to changes in nutrient loadings. A physiological fauna model with 5 functional groups was linked to a 3D coupled hydrodynamic-ecological Baltic Sea model. Model results revealed that benthic biomass increased between 0 and 700% after re-oxygenating bottom waters. Nutrient reduction scenarios indicated improved oxygen concentrations in bottom waters and decreased sedimentation of organic matter up to 40% after a nutrient load reduction following the Baltic Sea Action Plan. The lower food supply to benthos reduced the macrofaunal biomass up to 35% especially in areas not currently affected by hypoxia, whereas benthic biomass increased up to 200% in areas affected by eutrophication-induced hypoxia. The expected changes in benthic biomass resulting from nutrient load reductions and subsequent reduced hypoxia may not only increase the food supply for benthivorous fish, but also significantly affect the biogeochemical functioning of the ecosystem.

  9. Biosurfactant yields and nutrient consumption of Pseudomonas fluorescens 378 studied in a microcomputer controlled multifermentation system.

    PubMed

    Persson, A; Molin, G; Andersson, N; Sjöholm, J

    1990-07-01

    Production of biosurfactant AP-6 and consumption of carbon (succinic acid) and nitrogen (ammonium ions) by Pseudomonas fluorescens 378 were studied under different growth conditions. The study was performed in a microcomputer controlled multibatch fermentation system which enabled simultaneous running of 10 fermentors. The fermentors were mantled glass vessels, temperature controlled by circulated water, and mixing was arranged by magnetic stirrers. They were connected to the computer system (pH measurement and control) via signal conditioning cards. The microcomputer had a 128 kbytes RAM, two 800-kbyte floppy disc drives, a graphic terminal, and expansion cards. Biosurfactant production was independent of the carbon-to-nitrogen ratio and the phosphorus content in the medium. Omitting the Fe(III) supplement to the medium increased the product yield by 120%. Changes in oxygen transfer rate and pH in the iron deficient cultures did not have any effect on the product yield. Iron deficiency increased the cell consumption of carbon source. Consumption of carbon source in relation to nitrogen uptake (carbon/nitrogen quotient) increased with increasing quotient in the growth medium. The uptake of carbon and nitrogen changed in the intervals of 1.2-1.5 g/g biomass and 0.09-0.16 g/g biomass, respectively. The consumption of carbon increased from 1.5 g/g biomass to 2.0 g/g biomass when the medium concentration of phosphorus was decreased from 0.18 to 0.027 g/L. PMID:18595075

  10. Understanding and Changing Food Consumption Behavior Among Children: The Comprehensive Child Consumption Patterns Model.

    PubMed

    Jeffries, Jayne K; Noar, Seth M; Thayer, Linden

    2015-01-01

    Current theoretical models attempting to explain diet-related weight status among children center around three individual-level theories. Alone, these theories fail to explain why children are engaging or not engaging in health-promoting eating behaviors. Our Comprehensive Child Consumption Patterns model takes a comprehensive approach and was developed specifically to help explain child food consumption behavior and addresses many of the theoretical gaps found in previous models, including integration of the life course trajectory, key influencers, perceived behavioral control, and self-regulation. Comprehensive Child Consumption Patterns model highlights multiple levels of the socioecological model to explain child food consumption, illustrating how negative influence at multiple levels can lead to caloric imbalance and contribute to child overweight and obesity. Recognizing the necessity for multi-level and system-based interventions, this model serves as a template for holistic, integrated interventions to improve child eating behavior, ultimately impacting life course health development. PMID:26518599

  11. Nutrient Dynamics in Flooded Wetlands. II: Model Application

    EPA Science Inventory

    In this paper we applied and evaluated the wetland nutrient model described in an earlier paper. Hydrologic and water quality data from a small restored wetland located on Kent Island, Maryland, which is part of the Delmarva Peninsula on the Eastern shores of the Chesapeake Bay...

  12. An electricity consumption model for electric vehicular flow

    NASA Astrophysics Data System (ADS)

    Xiao, Hong; Huang, Hai-Jun; Tang, Tie-Qiao

    2016-09-01

    In this paper, we apply the relationships between the macro and micro variables of traffic flow to develop an electricity consumption model for electric vehicular flow. We use the proposed model to study the quantitative relationships between the electricity consumption/total power and speed/density under uniform flow, and the electricity consumptions during the evolution processes of shock, rarefaction wave and small perturbation. The numerical results indicate that the proposed model can perfectly describe the electricity consumption for electric vehicular flow, which shows that the proposed model is reasonable.

  13. Nutrient-dependent/pheromone-controlled adaptive evolution: a model

    PubMed Central

    Kohl, James Vaughn

    2013-01-01

    Background The prenatal migration of gonadotropin-releasing hormone (GnRH) neurosecretory neurons allows nutrients and human pheromones to alter GnRH pulsatility, which modulates the concurrent maturation of the neuroendocrine, reproductive, and central nervous systems, thus influencing the development of ingestive behavior, reproductive sexual behavior, and other behaviors. Methods This model details how chemical ecology drives adaptive evolution via: (1) ecological niche construction, (2) social niche construction, (3) neurogenic niche construction, and (4) socio-cognitive niche construction. This model exemplifies the epigenetic effects of olfactory/pheromonal conditioning, which alters genetically predisposed, nutrient-dependent, hormone-driven mammalian behavior and choices for pheromones that control reproduction via their effects on luteinizing hormone (LH) and systems biology. Results Nutrients are metabolized to pheromones that condition behavior in the same way that food odors condition behavior associated with food preferences. The epigenetic effects of olfactory/pheromonal input calibrate and standardize molecular mechanisms for genetically predisposed receptor-mediated changes in intracellular signaling and stochastic gene expression in GnRH neurosecretory neurons of brain tissue. For example, glucose and pheromones alter the hypothalamic secretion of GnRH and LH. A form of GnRH associated with sexual orientation in yeasts links control of the feedback loops and developmental processes required for nutrient acquisition, movement, reproduction, and the diversification of species from microbes to man. Conclusion An environmental drive evolved from that of nutrient ingestion in unicellular organisms to that of pheromone-controlled socialization in insects. In mammals, food odors and pheromones cause changes in hormones such as LH, which has developmental affects on pheromone-controlled sexual behavior in nutrient-dependent reproductively fit individuals

  14. Evaluation of the Relative Validity of the Short Diet Questionnaire for Assessing Usual Consumption Frequencies of Selected Nutrients and Foods.

    PubMed

    Shatenstein, Bryna; Payette, Hélène

    2015-08-01

    A 36-item Short Diet Questionnaire (SDQ) was developed to assess usual consumption frequencies of foods providing fats, fibre, calcium, vitamin D, in addition to fruits and vegetables. It was pretested among 30 community-dwelling participants from the Québec Longitudinal Study on Nutrition and Successful Aging, "NuAge" (n = 1793, 52.4% women), recruited in three age groups (70 ± 2 years; 75 ± 2 years; 80 ± 2 years). Following revision, the SDQ was administered to 527 NuAge participants (55% female), distributed among the three age groups, both sexes and languages (French, English) prior to the second of three non-consecutive 24 h diet recalls (24HR) and validated relative to the mean of three 24HR. Full data were available for 396 participants. Most SDQ nutrients and fruit and vegetable servings were lower than 24HR estimates (p < 0.05) except calcium, vitamin D, and saturated and trans fats. Spearman correlations between the SDQ and 24HR were modest and significant (p < 0.01), ranging from 0.19 (cholesterol) to 0.45 (fruits and vegetables). Cross-classification into quartiles showed 33% of items were jointly classified into identical quartiles of the distribution, 73% into identical and contiguous quartiles, and only 7% were frankly misclassified. The SDQ is a reasonably accurate, rapid approach for ranking usual frequencies of selected nutrients and foods. Further testing is needed in a broader age range.

  15. Evaluation of the Relative Validity of the Short Diet Questionnaire for Assessing Usual Consumption Frequencies of Selected Nutrients and Foods

    PubMed Central

    Shatenstein, Bryna; Payette, Hélène

    2015-01-01

    A 36-item Short Diet Questionnaire (SDQ) was developed to assess usual consumption frequencies of foods providing fats, fibre, calcium, vitamin D, in addition to fruits and vegetables. It was pretested among 30 community-dwelling participants from the Québec Longitudinal Study on Nutrition and Successful Aging, “NuAge” (n = 1793, 52.4% women), recruited in three age groups (70 ± 2 years; 75 ± 2 years; 80 ± 2 years). Following revision, the SDQ was administered to 527 NuAge participants (55% female), distributed among the three age groups, both sexes and languages (French, English) prior to the second of three non-consecutive 24 h diet recalls (24HR) and validated relative to the mean of three 24HR. Full data were available for 396 participants. Most SDQ nutrients and fruit and vegetable servings were lower than 24HR estimates (p < 0.05) except calcium, vitamin D, and saturated and trans fats. Spearman correlations between the SDQ and 24HR were modest and significant (p < 0.01), ranging from 0.19 (cholesterol) to 0.45 (fruits and vegetables). Cross-classification into quartiles showed 33% of items were jointly classified into identical quartiles of the distribution, 73% into identical and contiguous quartiles, and only 7% were frankly misclassified. The SDQ is a reasonably accurate, rapid approach for ranking usual frequencies of selected nutrients and foods. Further testing is needed in a broader age range. PMID:26247965

  16. Antioxidant capacity total in non-melanoma skin cancer and its relationship with food consumption of antioxidant nutrients.

    PubMed

    Freitas, Betânia e Silva de Almendra; de Castro, Laís Lima; Aguiar, Jordana Rayane Sousa; de Araújo, Camila Guedes Borges; Visacri, Marília Berlofa; Tuan, Bruna Taliani; Pincinato, Eder de Carvalho; Moriel, Patricia

    2015-04-01

    The non-melanoma skin cancer is the most common cancer and accounts for more than half of the diagnoses of cancer, and basal cell carcinoma (BCC), the most frequent cutaneous neoplasm, corresponding to 70-80% of cutaneous tumors. Oxidative stress is an important trigger for skin carcinogenesis. Thus, it is important to evaluate oxidative stress, in order to discern effective therapeutic strategies able to stop it or attenuate it, thereby prevent the installation of non-melanoma skin cancer. Cross-sectional study with controls, involving 84 individuals of both sexes aged between 38-84 years, divided into two groups: control group of healthy people(n = 24) and the case group included individuals who presented non-melanoma skin and they have undergoing surgery (n = 60). The blood samples of the individuals were obtained for evaluation of biomarkers of oxidative stress (F2-isoprostane, nitrite, thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity). The usual dietary intake and nutritional status of the subjects were evaluated. The significance level for this study was 5%. Patients in the case group had higher serum concentrations of biomarkers of oxidative stress, F2-isoprostane concentrations were significantly higher compared to controls. The results showed high rates of overweight and obesity in the case and control groups. The dietary concentrations of antioxidant minerals zinc, copper and selenium in the case group were significantly lower compared to controls. The correlation between markers of oxidative stress and dietary concentrations of antioxidant nutrients showed the influence of food intake of vitamins A and E in reducing oxidative stress, since these nutrients behave as important antioxidants, acting as sweepers of RL, by removing of the body the negative effects on the redox balance of the skin. We emphasize the importance of adopting healthy eating habits that optimize the consumption of antioxidant nutrients as a strategy to

  17. Modelling and simulation of nutrient dispersion from coated fertilizer granules

    NASA Astrophysics Data System (ADS)

    Razali, Radzuan; Daud, Hanita; Nor, Shafiq Mohd.

    2014-10-01

    The usage of Controlled-Release Fertilizer (CRF) is essential in plants and crops to fulfill the need and requirement for the modern agriculture which now feeds 6 billion people. Therefore modeling and simulation of nutrient release from coated fertilizer has become the best method to study the behavior of some parameters toward water saturation in and nutrient release from the coated-fertilizer granule. This paper is the improvement development of modeling and computer simulation by Basu [1] which include some of the factors affecting the water saturation time and nutrient release time from a coated-fertilizer. The effect of granule radius, the diffusivity of water and nutrient, the temperature of surrounding, the contact areas and the characteristic of the coating are studied and the simulation was developed using MATLAB software. The studies and understanding of this project is very important and useful especially to determine the important parameters in the manufacturing process of the coated-fertilizer granule and also will be useful for the farmers/users in the selection of the best fertilizers for their crops.

  18. Food Consumption and Nutrient Intake by Children Aged 10 to 48 Months Attending Day Care in The Netherlands

    PubMed Central

    Goldbohm, R. Alexandra; Rubingh, Carina M.; Lanting, Caren I.; Joosten, Koen F. M.

    2016-01-01

    The diet of young children is an important determinant of long-term health effects, such as overweight and obesity. We analyzed two-day food consumption records from 1526 young children (10–48 months old) attending 199 daycare centers across The Netherlands. Data were observed and recorded in diaries by caregivers at the day nursery and by parents at home on days that the children attended the daycare center. According to national and European reference values, the children had an adequate nutrient intake with exception of low intakes of total fat, n-3 fatty acids from fish and possibly iron. Intakes of energy and protein were substantially higher than recommended and part of the population exceeded the tolerable upper intake levels for sodium, zinc and retinol. Consumption of fruit, fats, fish, and fluids was substantially less than recommended. The children used mostly (semi-)skimmed milk products and non-refined bread and cereals, as recommended. Two thirds of the consumed beverages, however, contained sugar and contributed substantially to energy intake. In young children, low intakes of n-3 fatty acids and iron are a potential matter of concern, as are the high intakes of energy, protein, sugared beverages, and milk, since these may increase the risk of becoming overweight. PMID:27428995

  19. Food Consumption and Nutrient Intake by Children Aged 10 to 48 Months Attending Day Care in The Netherlands.

    PubMed

    Goldbohm, R Alexandra; Rubingh, Carina M; Lanting, Caren I; Joosten, Koen F M

    2016-01-01

    The diet of young children is an important determinant of long-term health effects, such as overweight and obesity. We analyzed two-day food consumption records from 1526 young children (10-48 months old) attending 199 daycare centers across The Netherlands. Data were observed and recorded in diaries by caregivers at the day nursery and by parents at home on days that the children attended the daycare center. According to national and European reference values, the children had an adequate nutrient intake with exception of low intakes of total fat, n-3 fatty acids from fish and possibly iron. Intakes of energy and protein were substantially higher than recommended and part of the population exceeded the tolerable upper intake levels for sodium, zinc and retinol. Consumption of fruit, fats, fish, and fluids was substantially less than recommended. The children used mostly (semi-)skimmed milk products and non-refined bread and cereals, as recommended. Two thirds of the consumed beverages, however, contained sugar and contributed substantially to energy intake. In young children, low intakes of n-3 fatty acids and iron are a potential matter of concern, as are the high intakes of energy, protein, sugared beverages, and milk, since these may increase the risk of becoming overweight. PMID:27428995

  20. Trends in food consumption and nutrient intake in Germany between 2006 and 2012: results of the German National Nutrition Monitoring (NEMONIT).

    PubMed

    Gose, Maria; Krems, Carolin; Heuer, Thorsten; Hoffmann, Ingrid

    2016-04-01

    The German National Nutrition Monitoring (NEMONIT) is a longitudinal and nationwide study to assess changes in food consumption and nutrient intake in Germany. A sample of 1840 participants (baseline age: 14-80 years) was drawn from the nationally representative German National Nutrition Survey (NVS) II (2005-2007). The participants have been interviewed by telephone annually since 2008. Food consumption was assessed by two 24-h recalls in the NVS II and the 4 years of NEMONIT (2008-2012/2013), respectively. Energy and nutrient intakes were calculated using the German Nutrient Database 3.02. Diet quality was evaluated using the Healthy Eating Index-NVS (HEI-NVS) II. Time trends were analysed by generalised estimating equation. Consumption of fruit/fruit products and fruit juice/nectar among men and women decreased, whereas consumption of water, soft drinks and coffee/tea increased over the 6-year period. Furthermore, increased consumption of confectionery and animal fats was observed among women. HEI-NVS II did not change since NVS II in both sexes. There were no changes in energy and protein intakes, but carbohydrate intake declined while fat intake increased over time. Regarding micronutrients, a decreasing intake of thiamin, riboflavin and vitamin B6 was observed in both sexes, but intake of Mg, Fe and niacin increased among women over time. In conclusion, food consumption and nutrient intake remained relatively stable between 2005-2007 and 2012/2013 within this German cohort. A few favourable and unfavourable changes were observed. Compared with national dietary guidelines, consumption of food of plant origin remained too low and consumption of meat/meat products remained too high in Germany. PMID:26934826

  1. Trends in food consumption and nutrient intake in Germany between 2006 and 2012: results of the German National Nutrition Monitoring (NEMONIT).

    PubMed

    Gose, Maria; Krems, Carolin; Heuer, Thorsten; Hoffmann, Ingrid

    2016-04-01

    The German National Nutrition Monitoring (NEMONIT) is a longitudinal and nationwide study to assess changes in food consumption and nutrient intake in Germany. A sample of 1840 participants (baseline age: 14-80 years) was drawn from the nationally representative German National Nutrition Survey (NVS) II (2005-2007). The participants have been interviewed by telephone annually since 2008. Food consumption was assessed by two 24-h recalls in the NVS II and the 4 years of NEMONIT (2008-2012/2013), respectively. Energy and nutrient intakes were calculated using the German Nutrient Database 3.02. Diet quality was evaluated using the Healthy Eating Index-NVS (HEI-NVS) II. Time trends were analysed by generalised estimating equation. Consumption of fruit/fruit products and fruit juice/nectar among men and women decreased, whereas consumption of water, soft drinks and coffee/tea increased over the 6-year period. Furthermore, increased consumption of confectionery and animal fats was observed among women. HEI-NVS II did not change since NVS II in both sexes. There were no changes in energy and protein intakes, but carbohydrate intake declined while fat intake increased over time. Regarding micronutrients, a decreasing intake of thiamin, riboflavin and vitamin B6 was observed in both sexes, but intake of Mg, Fe and niacin increased among women over time. In conclusion, food consumption and nutrient intake remained relatively stable between 2005-2007 and 2012/2013 within this German cohort. A few favourable and unfavourable changes were observed. Compared with national dietary guidelines, consumption of food of plant origin remained too low and consumption of meat/meat products remained too high in Germany.

  2. Statistical modelling of variability in sediment-water nutrient and oxygen fluxes

    NASA Astrophysics Data System (ADS)

    Serpetti, Natalia; Witte, Ursula; Heath, Michael

    2016-06-01

    Organic detritus entering, or produced, in the marine environment is re-mineralised to inorganic nutrient in the seafloor sediments. The flux of dissolved inorganic nutrient between the sediment and overlying water column is a key process in the marine ecosystem, which binds the biogeochemical sub-system to the living food web. These fluxes are potentially affected by a wide range of physical and biological factors and disentangling these is a significant challenge. Here we develop a set of General Additive Models (GAM) of nitrate, nitrite, ammonia, phosphate, silicate and oxygen fluxes, based on a year-long campaign of field measurements off the north-east coast of Scotland. We show that sediment grain size, turbidity due to sediment re-suspension, temperature, and biogenic matter content were the key factors affecting oxygen consumption, ammonia and silicate fluxes. However, phosphate fluxes were only related to suspended sediment concentrations, whilst nitrate fluxes showed no clear relationship to any of the expected drivers of change, probably due to the effects of denitrification. Our analyses show that the stoichiometry of nutrient regeneration in the ecosystem is not necessarily constant and may be affected by combinations of processes. We anticipate that our statistical modelling results will form the basis for testing the functionality of process-based mathematical models of whole-sediment biogeochemistry.

  3. Cooked oatmeal consumption is associated with better diet quality, better nutrient intakes, and reduced risk for central adiposity and obesity in Children 2-18 years

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to assess the association between oatmeal consumption and nutrient intake, diet quality, and weight/adiposity of children aged 2-18. A nationally representative sample of children aged 2-18 (N=14,690) participating in National Health and Nutrition Examination Survey 2...

  4. Improved diet quality, nutrient intake, and health associated with out-of-hand tree nut consumption in U.S. adults: NHANES 1999–2004

    Technology Transfer Automated Retrieval System (TEKTRAN)

    HANES (1999–2004), data were used to examine the association of out-of-hand tree nut consumption (almonds, Brazil nuts, cashews, filberts, macadamias, pecans, pine nuts, pistachios, and walnuts) with diet quality, nutrient intakes, and health risks in adults 19+ yrs (n equals 13,292). Using 24 hour ...

  5. 100% Orange juice consumption is associated with better diet quality, improved nutrient adequacy, decreased risk for obesity, and improved biomarkers of health in adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of 100% orange juice (OJ) has been positively associated with nutrient adequacy and diet quality, with no increased risk of overweight/obesity in children; however, no one has examined these factors in adults. The purpose of this study was to examine the association of 100% orange juice ...

  6. Out-of-hand nut consumption is associated with improved nutrient intake and health risk markers in US children and adults: NHANES 1999-2004

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to determine the association of out-of-hand nut (OOHN) consumption with nutrient intake, diet quality, and the prevalence of risk factors for cardiovascular disease and metabolic syndrome. Data from 24-hour recalls from individuals aged 2+ years (n = 24,385) participati...

  7. Ecosystem modeling applied to nutrient criteria development in rivers.

    PubMed

    Carleton, James N; Park, Richard A; Clough, Jonathan S

    2009-09-01

    Threshold concentrations for biological impairment by nutrients are difficult to quantify in lotic systems, yet States and Tribes in the United States are charged with developing water quality criteria to protect these ecosystems from excessive enrichment. The analysis described in this article explores the use of the ecosystem model AQUATOX to investigate impairment thresholds keyed to biological indexes that can be simulated. The indexes selected for this exercise include percentage cyanobacterial biomass of sestonic algae, and benthic chlorophyll a. The calibrated model was used to analyze responses of these indexes to concurrent reductions in phosphorus, nitrogen, and suspended sediment in an enriched upper Midwestern river. Results suggest that the indexes would respond strongly to changes in phosphorus and suspended sediment, and less strongly to changes in nitrogen concentration. Using simulated concurrent reductions in all three water quality constituents, a total phosphorus concentration of 0.1 mg/l was identified as a threshold concentration, and therefore a hypothetical water quality criterion, for prevention of both excessive periphyton growth and sestonic cyanobacterial blooms. This kind of analysis is suggested as a way to evaluate multiple contrasting impacts of hypothetical nutrient and sediment reductions and to define nutrient criteria or target concentrations that balance multiple management objectives concurrently.

  8. A closed NPZ model with delayed nutrient recycling.

    PubMed

    Kloosterman, Matt; Campbell, Sue Ann; Poulin, Francis J

    2014-03-01

    We consider a closed Nutrient-Phytoplankton-Zooplankton (NPZ) model that allows for a delay in the nutrient recycling. A delay-dependent conservation law allows us to quantify the total biomass in the system. With this, we can investigate how a planktonic ecosystem is affected by the quantity of biomass it contains and by the properties of the delay distribution. The quantity of biomass and the length of the delay play a significant role in determining the existence of equilibrium solutions, since a sufficiently small amount of biomass or a long enough delay can lead to the extinction of a species. Furthermore, the quantity of biomass and length of delay are important since a small change in either can change the stability of an equilibrium solution. We explore these effects for a variety of delay distributions using both analytical and numerical techniques, and verify these results with simulations.

  9. Adaptive contraction of diet breadth affects sexual maturation and specific nutrient consumption in an extreme generalist omnivore.

    PubMed

    Jensen, K; Schal, C; Silverman, J

    2015-04-01

    Animals balance their intake of specific nutrients, but little is known about how they do so when foraging in an environment with toxic resources and whether toxic foods promote adaptations that affect life history traits. In German cockroach (Blattella germanica) populations, glucose aversion has evolved in response to glucose-containing insecticidal baits. We restricted newly eclosed glucose-averse (GA) and wild-type (WT) female cockroaches to nutritionally defined diets varying in protein-to-carbohydrate (P : C) ratio (3 : 1, 1 : 1, or 1 : 3) or gave them free choice of the 3 : 1 and 1 : 3 diets, with either glucose or fructose as the sole carbohydrate source. We measured consumption of each diet over 6 days and then dissected the females to measure the length of basal oocytes in their ovaries. Our results showed significantly lower consumption by GA compared to WT cockroaches when restricted to glucose-containing diets, but also lower fructose intake by GA compared to WT cockroaches when restricted to high fructose diets or given choice of fructose-containing diets. Protein intake was regulated tightly regardless of carbohydrate intake, except by GA cockroaches restricted to glucose-containing diets. Oocyte growth was completely suppressed in GA females restricted to glucose-containing diets, but also significantly slower in GA than in WT females restricted to fructose-containing diets. Our findings suggest that GA cockroaches have adapted to reduced diet breadth through endocrine adjustments which reduce requirements for energetic fuels. Our study illustrates how an evolutionary change in the chemosensory system may affect the evolution of other traits that govern animal life histories.

  10. Modelling of the Nutrient Medium for Plants Cultivation in Spaceflight

    NASA Astrophysics Data System (ADS)

    Nechitailo, Galina S.

    2016-07-01

    MODELLING OF THE NUTRIENT MEDIUM FOR PLANTS CULTIVATION IN SPACEFLIGHT Nechitajlo G.S.*, Rakhmetova A.A.**, Bogoslovskaja O.A.**, Ol'hovskay I.P.**, Glushchenko N.N.** *Emanuel Institute of Biochemical Physics of Russian Academy of Sciences (IBCP RAS) mail: spacemal@mail.ru **V.L. Talrose Institute for Energy Problems of Chemical Physics of Russian Academy of Science (INEPCP RAS) mail: nnglu@ mail.ru The valuable life and fruitful activity of cosmonauts and researchers in conditions of spaceflights and prolonged work at space stations are only possible with creating life area providing fresh air, natural food, comfortable psychological conditions, etc. The solution of that problem under space conditions seems impossible without use of high nano- and biotechnologies for plants growth. A priority should be given not only to choose species of growth plants in space, but also to improve conditions for their growth which includes optimal nourishing components for plants, preparation of nutrient mediums, illumination and temperature. We are deeply convinced that just manipulations with growing conditions for cultivated plants, but not genes changes, is a guarantee of success in the decision of this problem. For improving the method of plants growing on the artificial nutrient medium with balanced content of components, being necessary for growth and development of plants, we added essential metal elements: Fe, Zn, Cu - in an electroneutral state in the form of nanoparticles instead of sulfates or other easily dissolving salts. Nanoparticulated metals are known to have a number of advantages in comparison with salts: metals in an electroneutral form are characterized with the prolonged and multifunctional action, low toxicity per se and appearing to be much below the toxicity of the same metals in the ionic forms, accumulation as a reserve being used in biotic dozes, active distribution in bodies and organs of plants and stimulation of vital processes. A high reactivity

  11. Modelling global nutrient retention by river damming: Phosphorus and silicon

    NASA Astrophysics Data System (ADS)

    Maavara, Taylor; Dürr, Hans; Van Cappellen, Philippe

    2014-05-01

    The phosphorus to silicon (P:Si) nutrient ratio is a key variable affecting ecosystem health in many aquatic environments. River damming represents a major anthropogenic perturbation of natural material flows along the aquatic continuum, with the potential to profoundly modify absolute and relative nutrient availabilities in surface waters. In this study, a multi-tiered approach for estimating global nutrient retention in man-made reservoirs is presented. We illustrate its application to the global riverine flux of reactive Si, using a database of dissolved reactive Si (DSi) budgets for 24 natural lakes and 22 artificial reservoirs. The database includes information on bedrock geology, surface water pH, water residence time, reservoir age and function, climate, and trophic status. Statistical analyses (ANOVA, t-test, PCA, linear plus non-linear regressions) are used to identify the best predictors of DSi retention and delineate how reservoir properties modulate nutrient dynamics. Results indicate that (1) reservoirs retain significantly less DSi than natural lakes, and (2) the water residence time, reservoir age and function (e.g., hydroelectrical production, irrigation, flood control) are the main system variables controlling DSi retention by dams. Next, a biogeochemical Si model is used to reproduce the previously derived statistical trends for DSi retention. Calibration of the model yields a relationship that enables one to predict annual in-reservoir siliceous productivity as a function of the external reactive Si supply. The model further accounts for the transition from reservoirs where reactive Si retention is primarily due to burial of allochtonous Si to those where in-reservoir DSi uptake by diatoms dominates. Finally, the statistical and mechanistic relationships are extrapolated to estimate that 25-28 Tg SiO2 yr-1 are retained worldwide by dams, or 7% of the annual reactive Si load to watersheds. We are currently applying the same multi-tiered approach

  12. Nutrient Uptake by Protocells: A Liposome Model System

    NASA Astrophysics Data System (ADS)

    Monnard, Pierre-Alain; Deamer, David W.

    2001-02-01

    Over the past decade, several liposome-based models for protocells have been developed. For example, liposome systems composed of polymerase enzymes encapsulated with their substrates have demonstrated that complex compartmentalized reactions can be carried out under conditions in which polymeric products are protected from degradation by hydrolytic enzymes present in the external medium. However, such systems do not have nutrient uptake mechanisms, which would be essential for primitive cells lacking the highly evolved nutrient transport processes present in all contemporary cells. In this report, we explore passive diffusion of solutes across lipid bilayers as one possible uptake mechanism. We have established conditions under which ionic substrates as large as ATP can permeate bilayers at rates capable of supplying an encapsulated template-dependent RNA polymerase. Furthermore, while allowing the permeation of monomer substrates such as ATP, bilayer vesicles selectively retained polymerization products as small as dimers and as large as a transfer RNA. These observations demonstrate that passive diffusion could be used by the earliest forms of cellular life for transport of important nutrients such as amino acids, phosphate, and phosphorylated organic solutes.

  13. Nutrient-controlled growth of Skeletonema costatum: an applied model

    NASA Astrophysics Data System (ADS)

    Sun, Ke; Qiu, Zhongfeng; He, Yijun; Yin, Baoshu

    2014-05-01

    To model Skeletonema costatum blooms and their relationship with environmental parameters in situ, a S. costatum-specific zero-dimensional box model based on the mechanistic model Eco3M was established using physiological features. The parameters were calibrated using experimental counterparts, and simulations were compared with published laboratory findings. The resulting normalized objective function (NOF) values are less than 1.0 (and in most cases less than 0.58) and the values for the slope γ (between 0.656 7-1.127 4) and R 2 (between 0.806 8-0.971) are close to 1.0 for most of the sub-figures. This indicates good agreement between simulated and measured data and suggests that the model reproduces the general characteristics of S. costatum growth and use of nutrients under different N- or P-limiting conditions. The model is appropriate for further applications and can be used to test more scenarios using other nutrients.

  14. Modeling priming effects on microbial consumption of dissolved organic carbon in rivers

    NASA Astrophysics Data System (ADS)

    Hotchkiss, E. R.; Hall, R. O.; Baker, M. A.; Rosi-Marshall, E. J.; Tank, J. L.

    2014-05-01

    Rivers receive and process large quantities of terrestrial dissolved organic carbon (DOC). Biologically available (unstable) DOC leached from primary producers may stimulate (i.e., prime) the consumption of more stable terrestrially derived DOC by heterotrophic microbes. We measured microbial DOC consumption (i.e., decay rates) from contrasting C sources in 10 rivers in the western and Midwestern United States using short-term bioassays of river water, soil and algal leachates, glucose, and commercial humate. We added inorganic nutrients (ammonium and phosphorus) to a subset of bioassays. We also amended a subset of river, soil, and commercial humate bioassays with glucose or algal leachates to test the hypothesis that unstable DOC primes consumption of more stable DOC. We used prior measurements of source-specific DOC bioavailability, linked with a Bayesian process model, to estimate means and posterior probability distributions for source-specific DOC decay rates in multisource bioassays. Modeled priming effects ranged from a -130 to +370% change in more stable DOC decay when incubated with unstable DOC. Glucose increased modeled river DOC decay by an average of 87% among all rivers. Glucose and algal leachates increased soil leachate and commercial humate decay by an average of 25% above background rates. Inorganic nutrient additions did not have consistent effects on DOC decay, likely because most of the study rivers had high ambient background nutrients. Our results demonstrate that the priming effect can augment DOC decay in rivers. In addition, Bayesian models can be used to estimate mechanisms driving aquatic ecosystem processes that are difficult to measure directly.

  15. Spatial and seasonal variability of sediment oxygen consumption and nutrient fluxes at the sediment water interface in a sub-tropical lagoon (New Caledonia).

    PubMed

    Grenz, C; Denis, L; Pringault, O; Fichez, R

    2010-01-01

    In order to quantify the spatial and seasonal variations of sediment oxygen consumption and nutrient fluxes, we performed a spatial survey in the south west lagoon of New Caledonia during the two major seasons (dry and wet) based on a network of 11 sampling stations. Stations were selected along two barrier reef to land transects representing most types of sediments encountered in the lagoon. Fluxes were measured using ex-situ sediment incubations and compared to sediment characteristics. Sediment oxygen consumption (SOC) varied between 500 and 2000 micromol m(-2)h(-1), depending on season and stations. Nutrient effluxes from sediment were highly variable with highest fluxes measured in muddy sediments near the coast. Inter-sample variability was as high as seasonal differences so that no seasonally driven temperature effect could be observed on benthic nutrient fluxes in our temperature range. Nutrient fluxes, generally directed from the sediment to the water column, varied between -5.0 and 70.0 micromol m(-2)h(-1) for ammonia and between -2.5 and+12.5 micromol m(-2)h(-1) for PO(4) and NO(2+3). SOC and nutrient fluxes were compared to pelagic primary production rates in order to highlight the tight coupling existing between the benthic and pelagic compartments in this shallow tropical lagoon. Under specific occasions of low pelagic productivity, oxygen sediment consumption and related carbon and nutrient fluxes could balance nearly all net primary production in the lagoon. These biogeochemical estimates point to the functional importance of sediment biogeochemistry in the lagoon of New Caledonia.

  16. Soil nutrient competition in earth system models: an important but underappreciated driver of plant responses to nutrient fertilization

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Riley, W. J.; Tang, J.; Koven, C.

    2015-12-01

    Earth System Models (ESMs) used to project future biosphere-climate feedbacks rely on predictions of terrestrial carbon dynamics. Furthermore, soil nutrient availability strongly modulates land surface carbon dynamics, including plant sequestration of atmospheric CO2. Plant growth under future environmental changes (e.g., nitrogen and phosphorus deposition) depends on how well plants compete with microbial and abiotic competitors. Here, we surveyed recent developments of nutrient competition representations in ESMs that participated in the CMIP5 project. We found that nutrient competition is over-simplified despite its ecological significance. Existing ESMs either assume that soil-decomposing microbes (1) outcompete plants or (2) are evenly competitive, both of which are inconsistent with theoretical understanding and field observations. We compiled and synthesized global data of forest carbon productivity in response to nitrogen and phosphorus fertilization experiments. Using this synthesis, we show that existing ESMs with the first and second competition schemes lead to underestimation and overestimation, respectively, of fertilization effects on plant growth. We reduced these systematic biases by applying a new competition scheme in CLM4.5 and the essentially equivalent ACME land model (ALMv0) based on the Equilibrium Chemistry Approximation, which is based on classical equilibrium chemical kinetics theory. This approach dynamically updates nutrient competitiveness among multiple consumers (e.g., plants, decomposing microbes, nitrifier, denitrifier, mineral surfaces) as a function of soil nutrient status. There has been a long-term debate regarding how to implement theoretically realistic and computationally efficient nutrient competition schemes in ESMs. Our approach reconciles the complex nature of ecosystem nutrient competition with a computationally tractable approach applicable to ESMs. More importantly, our results imply that previous estimates of plant

  17. MODELING ENERGY EXPENDITURE AND OXYGEN CONSUMPTION IN HUMAN EXPOSURE MODELS: ACCOUNTING FOR FATIGUE AND EPOC

    EPA Science Inventory

    Human exposure and dose models often require a quantification of oxygen consumption for a simulated individual. Oxygen consumption is dependent on the modeled Individual's physical activity level as described in an activity diary. Activity level is quantified via standardized val...

  18. Tree nut consumption improves nutrient intake and diet quality in US adults: an analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004.

    PubMed

    O'Neil, Carol E; Keast, Debra R; Fulgoni, Victor L; Nicklas, Theresa A

    2010-01-01

    Recent epidemiologic studies assessing tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts) consumption and the association with nutrient intake and diet quality are lacking. This study determined the association of tree nut consumption and nutrient intake and diet quality using a nationally representative sample of adults. Adults 19+ years (y) (n=13,292) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. Intake was determined from 24-hour diet recalls; tree nut consumers were defined as those consuming > or =(1/4) ounce/day (7.09 g). Means, standard errors, and ANOVA (adjusted for covariates) were determined using appropriate sample weights. Diet quality was measured using the Healthy Eating Index-2005. Among consumers, mean intake of tree nuts/tree nut butters was 1.19 +/- 0.04 oz/d versus 0.01 +/- 0.00 oz/d for non-consumers. In this study, 5.5 +/- 0.3 % of individuals 19-50 y (n=7,049) and 8.4 +/- 0.6 % of individuals 51+ y (n=6,243) consumed tree nuts/tree nut butters. Mean differences (p<0.01) between tree nut consumers and non-consumers of adult shortfall nutrients were: fiber (+5.0 g/d), vitamin E (+3.7 mg AT/d), calcium (+73 mg/d), magnesium (+95 mg/d), and potassium (+260 mg/d). Tree nut consumers had lower sodium intake (-157 mg/d, p<0.01). Diet quality was significantly higher in tree nut consumers (58.0+/-0.4 vs. 48.5+/-0.3, p<0.01). Tree nut consumption was associated with a higher overall diet quality score and improved nutrient intakes. Specific dietary recommendations for nut consumption should be provided for consumers.

  19. Tree nut consumption improves nutrient intake and diet quality in US adults: an analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004.

    PubMed

    O'Neil, Carol E; Keast, Debra R; Fulgoni, Victor L; Nicklas, Theresa A

    2010-01-01

    Recent epidemiologic studies assessing tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts) consumption and the association with nutrient intake and diet quality are lacking. This study determined the association of tree nut consumption and nutrient intake and diet quality using a nationally representative sample of adults. Adults 19+ years (y) (n=13,292) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. Intake was determined from 24-hour diet recalls; tree nut consumers were defined as those consuming > or =(1/4) ounce/day (7.09 g). Means, standard errors, and ANOVA (adjusted for covariates) were determined using appropriate sample weights. Diet quality was measured using the Healthy Eating Index-2005. Among consumers, mean intake of tree nuts/tree nut butters was 1.19 +/- 0.04 oz/d versus 0.01 +/- 0.00 oz/d for non-consumers. In this study, 5.5 +/- 0.3 % of individuals 19-50 y (n=7,049) and 8.4 +/- 0.6 % of individuals 51+ y (n=6,243) consumed tree nuts/tree nut butters. Mean differences (p<0.01) between tree nut consumers and non-consumers of adult shortfall nutrients were: fiber (+5.0 g/d), vitamin E (+3.7 mg AT/d), calcium (+73 mg/d), magnesium (+95 mg/d), and potassium (+260 mg/d). Tree nut consumers had lower sodium intake (-157 mg/d, p<0.01). Diet quality was significantly higher in tree nut consumers (58.0+/-0.4 vs. 48.5+/-0.3, p<0.01). Tree nut consumption was associated with a higher overall diet quality score and improved nutrient intakes. Specific dietary recommendations for nut consumption should be provided for consumers. PMID:20200000

  20. Multi-asset investment-consumption model with transaction costs

    NASA Astrophysics Data System (ADS)

    Zhao, Xiao-Yan; Nie, Zan-Kan

    2005-09-01

    In this paper, we consider the multi-asset optimal investment-consumption model: a riskless asset and d risky assets. when the initial time is t[greater-or-equal, slanted]0, for a proportional transaction costs and discount factors, we proof that the value function of the model is a unique viscosity solution of a Hamilton-Jacobi-Bellman (HJB) equations.

  1. Control theoretic model of automobile demand and gasoline consumption

    SciTech Connect

    Panerali, R.B.

    1982-01-01

    The purpose of this research is to examine the controllability of gasoline consumption and automobile demand using gasoline price as a policy instrument. The author examines the problem of replacing the standby motor-fuel rationing plan with use of the federal excise tax on gasoline. It is demonstrated that the standby targets are attainable with the tax. The problem of multiple control of automobile demand and gasoline consumption is also addressed. When the federal gasoline excise tax is used to control gasoline consumption, the policy maker can also use the tax to direct automobile demand. There exists a trade-off between various automobile demand targets and the target implied for gasoline consumption. We seek to measure this trade-off and use the results for planning. This research employs a time series of cross section data base with a disaggregated model of automobile demand, and an aggregate model of gasoline consumption. Automobile demand is divided into five mutually exclusive classes of cars. Gasoline demand is model as the sum of regular, premium, and unleaded gasoline. The pooled data base is comprised of a quarterly time series running from 1963 quarter one through 1979 quarter four, for each of the 48 continuous states. The demand equations are modelled using dynamic theories of demand. Estimates of the respective equations are made with error components and covariance techniques. Optimal control is applied to examine the gasoline-control problem.

  2. Short-Term Energy Outlook Model Documentation: Motor Gasoline Consumption Model

    EIA Publications

    2011-01-01

    The motor gasoline consumption module of the Short-Term Energy Outlook (STEO) model is designed to provide forecasts of total U.S. consumption of motor gasolien based on estimates of vehicle miles traveled and average vehicle fuel economy.

  3. MODEL SIMULATION STUDIES OF SCALE-DEPENDENT GAIN IN STREAM NUTRIENT ASSIMILATIVE CAPACITY RESULTING FROM IMPROVING NUTRIENT RETENTION METRICS

    EPA Science Inventory

    Considering the difficulty in measuring restoration success for nonpoint source pollutants, nutrient assimilative capacity (NAS) offers an attractive systems-based metric. Here NAS was defined using an impulse-response model of nitrate fate and transport. Eleven parameters were e...

  4. Pan-European modelling of riverine nutrient concentrations - spatial patterns, source detection, trend analyses, scenario modelling

    NASA Astrophysics Data System (ADS)

    Bartosova, Alena; Arheimer, Berit; Capell, Rene; Donnelly, Chantal; Strömqvist, Johan

    2016-04-01

    Nutrient transport models are important tools for large scale assessments of macro-nutrient fluxes (nitrogen, phosphorus) and thus can serve as support tool for environmental assessment and management. Results from model applications over large areas, i.e. from major river basin to continental scales can fill a gap where monitoring data is not available. Here, we present results from the pan-European rainfall-runoff and nutrient transfer model E-HYPE, which is based on open data sources. We investigate the ability of the E-HYPE model to replicate the spatial and temporal variations found in observed time-series of riverine N and P concentrations, and illustrate the model usefulness for nutrient source detection, trend analyses, and scenario modelling. The results show spatial patterns in N concentration in rivers across Europe which can be used to further our understanding of nutrient issues across the European continent. E-HYPE results show hot spots with highest concentrations of total nitrogen in Western Europe along the North Sea coast. Source apportionment was performed to rank sources of nutrient inflow from land to sea along the European coast. An integrated dynamic model as E-HYPE also allows us to investigate impacts of climate change and measure programs, which was illustrated in a couple of scenarios for the Baltic Sea. Comparing model results with observations shows large uncertainty in many of the data sets and the assumptions used in the model set-up, e.g. point source release estimates. However, evaluation of model performance at a number of measurement sites in Europe shows that mean N concentration levels are generally well simulated. P levels are less well predicted which is expected as the variability of P concentrations in both time and space is higher. Comparing model performance with model set-ups using local data for the Weaver River (UK) did not result in systematically better model performance which highlights the complexity of model

  5. The MARINA model (Model to Assess River Inputs of Nutrients to seAs): Model description and results for China.

    PubMed

    Strokal, Maryna; Kroeze, Carolien; Wang, Mengru; Bai, Zhaohai; Ma, Lin

    2016-08-15

    Chinese agriculture has been developing fast towards industrial food production systems that discharge nutrient-rich wastewater into rivers. As a result, nutrient export by rivers has been increasing, resulting in coastal water pollution. We developed a Model to Assess River Inputs of Nutrients to seAs (MARINA) for China. The MARINA Nutrient Model quantifies river export of nutrients by source at the sub-basin scale as a function of human activities on land. MARINA is a downscaled version for China of the Global NEWS-2 (Nutrient Export from WaterSheds) model with an improved approach for nutrient losses from animal production and population. We use the model to quantify dissolved inorganic and organic nitrogen (N) and phosphorus (P) export by six large rivers draining into the Bohai Gulf (Yellow, Hai, Liao), Yellow Sea (Yangtze, Huai) and South China Sea (Pearl) in 1970, 2000 and 2050. We addressed uncertainties in the MARINA Nutrient model. Between 1970 and 2000 river export of dissolved N and P increased by a factor of 2-8 depending on sea and nutrient form. Thus, the risk for coastal eutrophication increased. Direct losses of manure to rivers contribute to 60-78% of nutrient inputs to the Bohai Gulf and 20-74% of nutrient inputs to the other seas in 2000. Sewage is an important source of dissolved inorganic P, and synthetic fertilizers of dissolved inorganic N. Over half of the nutrients exported by the Yangtze and Pearl rivers originated from human activities in downstream and middlestream sub-basins. The Yellow River exported up to 70% of dissolved inorganic N and P from downstream sub-basins and of dissolved organic N and P from middlestream sub-basins. Rivers draining into the Bohai Gulf are drier, and thus transport fewer nutrients. For the future we calculate further increases in river export of nutrients. The MARINA Nutrient model quantifies the main sources of coastal water pollution for sub-basins. This information can contribute to formulation of

  6. The MARINA model (Model to Assess River Inputs of Nutrients to seAs): Model description and results for China.

    PubMed

    Strokal, Maryna; Kroeze, Carolien; Wang, Mengru; Bai, Zhaohai; Ma, Lin

    2016-08-15

    Chinese agriculture has been developing fast towards industrial food production systems that discharge nutrient-rich wastewater into rivers. As a result, nutrient export by rivers has been increasing, resulting in coastal water pollution. We developed a Model to Assess River Inputs of Nutrients to seAs (MARINA) for China. The MARINA Nutrient Model quantifies river export of nutrients by source at the sub-basin scale as a function of human activities on land. MARINA is a downscaled version for China of the Global NEWS-2 (Nutrient Export from WaterSheds) model with an improved approach for nutrient losses from animal production and population. We use the model to quantify dissolved inorganic and organic nitrogen (N) and phosphorus (P) export by six large rivers draining into the Bohai Gulf (Yellow, Hai, Liao), Yellow Sea (Yangtze, Huai) and South China Sea (Pearl) in 1970, 2000 and 2050. We addressed uncertainties in the MARINA Nutrient model. Between 1970 and 2000 river export of dissolved N and P increased by a factor of 2-8 depending on sea and nutrient form. Thus, the risk for coastal eutrophication increased. Direct losses of manure to rivers contribute to 60-78% of nutrient inputs to the Bohai Gulf and 20-74% of nutrient inputs to the other seas in 2000. Sewage is an important source of dissolved inorganic P, and synthetic fertilizers of dissolved inorganic N. Over half of the nutrients exported by the Yangtze and Pearl rivers originated from human activities in downstream and middlestream sub-basins. The Yellow River exported up to 70% of dissolved inorganic N and P from downstream sub-basins and of dissolved organic N and P from middlestream sub-basins. Rivers draining into the Bohai Gulf are drier, and thus transport fewer nutrients. For the future we calculate further increases in river export of nutrients. The MARINA Nutrient model quantifies the main sources of coastal water pollution for sub-basins. This information can contribute to formulation of

  7. Prey-predator model with a nonlocal consumption of prey.

    PubMed

    Banerjee, M; Volpert, V

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology. PMID:27586616

  8. Prey-predator model with a nonlocal consumption of prey

    NASA Astrophysics Data System (ADS)

    Banerjee, M.; Volpert, V.

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology.

  9. Prey-predator model with a nonlocal consumption of prey.

    PubMed

    Banerjee, M; Volpert, V

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology.

  10. Long-term model study of nutrient and detritus dynamics in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Kõuts, Mariliis; Raudsepp, Urmas; Maljutenko, Ilja; Liis Treimann, Meri

    2015-04-01

    Eutrophication resulting from direct and indirect input of nutrients is considered one of the major environmental problems in the sub-basins of the Baltic Sea. Stronger eutrophication is manifested through increased summer cyanobacteria blooms and expanding hypoxia. It has been recognized that cycling of organic matter is a considerable source of nutrients in the Baltic Sea. Nutrient pools in the sediments have increased over the last decades. Our study aims at understanding the eutrophication of the Baltic Sea by looking at spatial patterns and temporal variation of biogeochemical parameters. We are focusing on spatial detritus dynamics during the period of 40 years in the Baltic Sea. Model simulations were performed using a three-dimensional free-surface hydrodynamic model GETM coupled with the ERGOM biogeochemical model. The model domain covers the entire Baltic Sea area and the period modelled is 1966-2006. Our results show that nutrient and detritus dynamics differ between shallow and deep areas. Seasonal cycle is dominant in the shallow areas (water depth less than 60 m approximately) and nutrients - organic matter are recycling there. Deep areas, however, could be storage areas of organic matter where halocline acts as a kind of barrier for nutrients to be transported to the upper layer. Still, nutrients are mixed from the upper halocline into the upper layer and fuel primary production there. Deep areas therefore become important source of nutrients especially during MBIs. Horizontal transport of nutrients from upstream basins of the Baltic Sea is a considerable source of nutrients for downstream basins.

  11. THE COMPARISON OF TWO WATERSHEDS USING A WATERSHED NUTRIENT LOADING MODEL

    EPA Science Inventory

    Monitoring data, collected from the Yaquina River, Oregon, from 1999 through 2002 were used as the basis for developing the nutrient flux model as part of a larger agency program for quantifying nutrient processes. The PNWL nitrate loading model indicates that the nitrate load is...

  12. Modelling C allocation in response to nutrient availability

    NASA Astrophysics Data System (ADS)

    Stocker, Benjamin; Prentice, Colin

    2015-04-01

    Carbon (C) allocation in ecosystems is a key variable of the global terrestrial C cycle. While photosynthesis governs the amount of C that enters ecosystems, its subsequent allocation to compartments with different life times determines its over-all residence time and variations in allocation patterns drive changes in ecosystem C balance and its response to environmental change. A better understanding of the controls on allocation is thus key to improving global vegetation models that commonly rely on using fixed partitioning factors. Observational data suggests variations of ecosystem structure and functioning along large-scale gradients of resource availability. Below-ground C allocation, inferred as gross primary production minus above-ground biomass production increases along gradients of decreasing nutrient availability. This is not only due to more root growth, but also due to enhanced production of exudates and stimulation of root symbionts and has been interpreted to reflect optimal plant allocation decisions under a varying soil fertility status. Here, we propose a model that accounts for trade-offs between (i) growth in above-ground and (ii) below-ground plant compartments, (iii) exudation to the rhizosphere and root symbionts and (iv) temporary storage in non-structural pools. By postulating the maximization of long-term growth under a given (seasonal regime) of soil nitrogen (N) availability, we attempt to reproduce observed large-scale gradients. The model is formulated based on a C cost for different N uptake decisions, where the cost is a function of N availability, root mass, and soil temperature (for biological N fixation). On a daily time scale, ecosystem N uptake may be realized by C exudation to the rhizosphere and/or symbiotic fixation of atmospheric N2. On an annual time scale, allocation to roots versus leaves is adjusted to soil inorganic N availability and modeled to yield maximum total growth. Exudation versus temporary storage of C is

  13. Testosterone and oestradiol in relation to tobacco smoking, body mass index, energy consumption and nutrient intake among adult men.

    PubMed

    Tamimi, R; Mucci, L A; Spanos, E; Lagiou, A; Benetou, V; Trichopoulos, D

    2001-06-01

    There is substantial evidence linking steroid hormones and diet to cancer aetiology. The evidence on lifestyle determinants of steroid hormones, however, is limited. We have conducted a study to identify dietary and other lifestyle predictors of testosterone and oestradiol among adult men. Subjects were 112 healthy Greek men, recruited as controls in a case-control study on the aetiology of liver cancer. Demographic data and detailed histories of smoking habits and alcohol consumption were recorded. Diet was assessed through an interviewer-administered validated food-frequency questionnaire. Serologic measurements of oestradiol, testosterone and sex hormone binding globulin were also conducted. We developed linear regression models to evaluate the associations of smoking and dietary factors with serum testosterone and oestradiol. The results indicate that, among men, both testosterone and oestradiol serum levels decline with age, whereas body mass index may be inversely related with testosterone and positively with oestradiol. The evidence concerning alcohol in relation to these hormones is inconclusive. Emerging evidence concerning smoking suggests positive associations with both hormones in the blood. The principal nutritional findings are a positive association of carbohydrate intake with testosterone levels and a set of inverse associations of vitamins with oestradiol.

  14. Sensitivity of hypoxia predictions for the northern Gulf of Mexico to sediment oxygen consumption and model nesting

    NASA Astrophysics Data System (ADS)

    Fennel, Katja; Hu, Jiatang; Laurent, Arnaud; Marta-Almeida, Martinho; Hetland, Robert

    2013-02-01

    Every summer, a large area (15,000 km2 on average) over the Texas-Louisiana shelf in the northern Gulf of Mexico turns hypoxic due to decay of organic matter that is primarily derived from nutrient inputs from the Mississippi/Atchafalaya River System. Interannual variability in the size of the hypoxic zone is large. The 2008 Action Plan put forth by the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force, an alliance of multiple state and federal agencies and tribes, calls for a reduction of the size of the hypoxic zone through nutrient management in the watershed. Comprehensive models help build mechanistic understanding of the processes underlying hypoxia formation and variability and are thus indispensable tools for devising efficient nutrient reduction strategies and for building reasonable expectations as to what responses can be expected for a given nutrient reduction. Here we present such a model, evaluate its hypoxia simulations against monitoring observations, and assess the sensitivity of the hypoxia simulations to model resolution, variations in sediment oxygen consumption, and choice of physical horizontal boundary conditions. We find that hypoxia simulations on the shelf are very sensitive to the parameterization of sediment oxygen consumption, a result of the fact that hypoxic conditions are restricted to a relatively thin layer above the bottom over most of the shelf. We show that the strength of vertical stratification is an important predictor of dissolved oxygen concentration in bottom waters and that modification of physical horizontal boundary conditions can have a large effect on hypoxia simulations because it can affect stratification strength.

  15. Modeling tribal exposures to methyl mercury from fish consumption.

    PubMed

    Xue, Jianping; Zartarian, Valerie; Mintz, Bruce; Weber, Marc; Bailey, Ken; Geller, Andrew

    2015-11-15

    Exposure assessment and risk management considerations for tribal fish consumption are different than for the general U.S. population because of higher fish intake from subsistence fishing and/or from unique cultural practices. This research summarizes analyses of available data and methodologies for estimating tribal fish consumption exposures to methyl mercury (MeHg). Large MeHg fish tissue data sets from the Environmental Protections Agency's (EPA's) Office of Water, USGS's EMMMA program, and other data sources, were integrated, analyzed, and combined with fish intake (consumption) data for exposure analyses using EPA's SHEDS-Dietary model. Results were mapped with GIS tools to depict spatial distributions of the MeHg in fish tissues and fish consumption exposure patterns. Contribution analyses indicates the major sources for those exposures, such as type and length of fish, geographical distribution (water bodies), and dietary exposure patterns. Sensitivity analyses identify the key variables and exposure pathways. Our results show that MeHg exposure of tribal populations from fish are about 3 to 10 times higher than the US general population and that exposure poses potential health risks. The estimated risks would be reduced as much as 50%, especially for high percentiles, just by avoiding consumption of fish species with higher MeHg concentrations such as walleye and bowfin, even without changing total fish intake. These exposure assessment methods and tools can help inform decisions regarding meal sizes and frequency, types of fish and water bodies to avoid, and other factors to minimize exposures and potential health risks from contaminated fish on tribal lands. PMID:26151654

  16. Modeling nutrient flows in the food chain of China.

    PubMed

    Ma, L; Ma, W Q; Velthof, G L; Wang, F H; Qin, W; Zhang, F S; Oenema, O

    2010-01-01

    Increasing nitrogen (N) and phosphorus (P) inputs have greatly contributed to the increasing food production in China during the last decades, but have also increased N and P losses to the environment. The pathways and magnitude of these losses are not well quantified. Here, we report on N and P use efficiencies and losses at a national scale in 2005, using the model NUFER (NUtrient flows in Food chains, Environment and Resources use). Total amount of "new" N imported to the food chain was 48.8 Tg in 2005. Only 4.4.Tg reached households as food. Average N use efficiencies in crop production, animal production, and the whole food chain were 26, 11, and 9%, respectively. Most of the imported N was lost to the environment, that is, 23 Tg N to atmosphere, as ammonia (57%), nitrous oxide (2%), dinitrogen (33%), and nitrogen oxides (8%), and 20 Tg to waters. The total P input into the food chain was 7.8 Tg. The average P use efficiencies in crop production, animal production, and the whole food chain were 36, 5, and 7%, respectively. This is the first comprehensive overview of N and P balances, losses, and use efficiencies of the food chain in China. It shows that the N and P costs of food are high (for N 11 kg kg(-1), for P 13 kg kg(-1)). Key measures for lowering the N and P costs of food production are (i) increasing crop and animal production, (ii) balanced fertilization, and (iii) improved manure management.

  17. Parameterization models for pesticide exposure via crop consumption.

    PubMed

    Fantke, Peter; Wieland, Peter; Juraske, Ronnie; Shaddick, Gavin; Itoiz, Eva Sevigné; Friedrich, Rainer; Jolliet, Olivier

    2012-12-01

    An approach for estimating human exposure to pesticides via consumption of six important food crops is presented that can be used to extend multimedia models applied in health risk and life cycle impact assessment. We first assessed the variation of model output (pesticide residues per kg applied) as a function of model input variables (substance, crop, and environmental properties) including their possible correlations using matrix algebra. We identified five key parameters responsible for between 80% and 93% of the variation in pesticide residues, namely time between substance application and crop harvest, degradation half-lives in crops and on crop surfaces, overall residence times in soil, and substance molecular weight. Partition coefficients also play an important role for fruit trees and tomato (Kow), potato (Koc), and lettuce (Kaw, Kow). Focusing on these parameters, we develop crop-specific models by parametrizing a complex fate and exposure assessment framework. The parametric models thereby reflect the framework's physical and chemical mechanisms and predict pesticide residues in harvest using linear combinations of crop, crop surface, and soil compartments. Parametric model results correspond well with results from the complex framework for 1540 substance-crop combinations with total deviations between a factor 4 (potato) and a factor 66 (lettuce). Predicted residues also correspond well with experimental data previously used to evaluate the complex framework. Pesticide mass in harvest can finally be combined with reduction factors accounting for food processing to estimate human exposure from crop consumption. All parametric models can be easily implemented into existing assessment frameworks. PMID:23136826

  18. Parameterization models for pesticide exposure via crop consumption.

    PubMed

    Fantke, Peter; Wieland, Peter; Juraske, Ronnie; Shaddick, Gavin; Itoiz, Eva Sevigné; Friedrich, Rainer; Jolliet, Olivier

    2012-12-01

    An approach for estimating human exposure to pesticides via consumption of six important food crops is presented that can be used to extend multimedia models applied in health risk and life cycle impact assessment. We first assessed the variation of model output (pesticide residues per kg applied) as a function of model input variables (substance, crop, and environmental properties) including their possible correlations using matrix algebra. We identified five key parameters responsible for between 80% and 93% of the variation in pesticide residues, namely time between substance application and crop harvest, degradation half-lives in crops and on crop surfaces, overall residence times in soil, and substance molecular weight. Partition coefficients also play an important role for fruit trees and tomato (Kow), potato (Koc), and lettuce (Kaw, Kow). Focusing on these parameters, we develop crop-specific models by parametrizing a complex fate and exposure assessment framework. The parametric models thereby reflect the framework's physical and chemical mechanisms and predict pesticide residues in harvest using linear combinations of crop, crop surface, and soil compartments. Parametric model results correspond well with results from the complex framework for 1540 substance-crop combinations with total deviations between a factor 4 (potato) and a factor 66 (lettuce). Predicted residues also correspond well with experimental data previously used to evaluate the complex framework. Pesticide mass in harvest can finally be combined with reduction factors accounting for food processing to estimate human exposure from crop consumption. All parametric models can be easily implemented into existing assessment frameworks.

  19. Low Calorie Beverage Consumption Is Associated with Energy and Nutrient Intakes and Diet Quality in British Adults

    PubMed Central

    Gibson, Sigrid A.; Horgan, Graham W.; Francis, Lucy E.; Gibson, Amelia A.; Stephen, Alison M.

    2016-01-01

    It is unclear whether consumption of low-calorie beverages (LCB) leads to compensatory consumption of sweet foods, thus reducing benefits for weight control or diet quality. This analysis investigated associations between beverage consumption and energy intake and diet quality of adults in the UK National Diet and Nutrition Survey (NDNS) (2008–2011; n = 1590), classified into: (a) non-consumers of soft drinks (NC); (b) LCB consumers; (c) sugar-sweetened beverage (SSB) consumers; or (d) consumers of both beverages (BB), based on 4-day dietary records. Within-person data on beverage consumption on different days assessed the impact on energy intake. LCB consumers and NC consumed less energy and non-milk extrinsic sugars than other groups. Micronutrient intakes and food choices suggested higher dietary quality in NC/LCB consumers compared with SSB/BB consumers. Within individuals on different days, consumption of SSB, milk, juice, and alcohol were all associated with increased energy intake, while LCB and tea, coffee or water were associated with no change; or reduced energy intake when substituted for caloric beverages. Results indicate that NC and LCB consumers tend to have higher quality diets compared with SSB or BB consumers and do not compensate for sugar or energy deficits by consuming more sugary foods. PMID:26729159

  20. Low Calorie Beverage Consumption Is Associated with Energy and Nutrient Intakes and Diet Quality in British Adults.

    PubMed

    Gibson, Sigrid A; Horgan, Graham W; Francis, Lucy E; Gibson, Amelia A; Stephen, Alison M

    2016-01-01

    It is unclear whether consumption of low-calorie beverages (LCB) leads to compensatory consumption of sweet foods, thus reducing benefits for weight control or diet quality. This analysis investigated associations between beverage consumption and energy intake and diet quality of adults in the UK National Diet and Nutrition Survey (NDNS) (2008-2011; n = 1590), classified into: (a) non-consumers of soft drinks (NC); (b) LCB consumers; (c) sugar-sweetened beverage (SSB) consumers; or (d) consumers of both beverages (BB), based on 4-day dietary records. Within-person data on beverage consumption on different days assessed the impact on energy intake. LCB consumers and NC consumed less energy and non-milk extrinsic sugars than other groups. Micronutrient intakes and food choices suggested higher dietary quality in NC/LCB consumers compared with SSB/BB consumers. Within individuals on different days, consumption of SSB, milk, juice, and alcohol were all associated with increased energy intake, while LCB and tea, coffee or water were associated with no change; or reduced energy intake when substituted for caloric beverages. Results indicate that NC and LCB consumers tend to have higher quality diets compared with SSB or BB consumers and do not compensate for sugar or energy deficits by consuming more sugary foods. PMID:26729159

  1. Low Calorie Beverage Consumption Is Associated with Energy and Nutrient Intakes and Diet Quality in British Adults.

    PubMed

    Gibson, Sigrid A; Horgan, Graham W; Francis, Lucy E; Gibson, Amelia A; Stephen, Alison M

    2016-01-02

    It is unclear whether consumption of low-calorie beverages (LCB) leads to compensatory consumption of sweet foods, thus reducing benefits for weight control or diet quality. This analysis investigated associations between beverage consumption and energy intake and diet quality of adults in the UK National Diet and Nutrition Survey (NDNS) (2008-2011; n = 1590), classified into: (a) non-consumers of soft drinks (NC); (b) LCB consumers; (c) sugar-sweetened beverage (SSB) consumers; or (d) consumers of both beverages (BB), based on 4-day dietary records. Within-person data on beverage consumption on different days assessed the impact on energy intake. LCB consumers and NC consumed less energy and non-milk extrinsic sugars than other groups. Micronutrient intakes and food choices suggested higher dietary quality in NC/LCB consumers compared with SSB/BB consumers. Within individuals on different days, consumption of SSB, milk, juice, and alcohol were all associated with increased energy intake, while LCB and tea, coffee or water were associated with no change; or reduced energy intake when substituted for caloric beverages. Results indicate that NC and LCB consumers tend to have higher quality diets compared with SSB or BB consumers and do not compensate for sugar or energy deficits by consuming more sugary foods.

  2. Employment, Production and Consumption model: Patterns of phase transitions

    NASA Astrophysics Data System (ADS)

    Lavička, H.; Lin, L.; Novotný, J.

    2010-04-01

    We have simulated the model of Employment, Production and Consumption (EPC) using Monte Carlo. The EPC model is an agent based model that mimics very basic rules of industrial economy. From the perspective of physics, the nature of the interactions in the EPC model represents multi-agent interactions where the relations among agents follow the key laws for circulation of capital and money. Monte Carlo simulations of the stochastic model reveal phase transition in the model economy. The two phases are the phase with full unemployment and the phase with nearly full employment. The economy switches between these two states suddenly as a reaction to a slight variation in the exogenous parameter, thus the system exhibits strong non-linear behavior as a response to the change of the exogenous parameters.

  3. Nutrient supply and mercury dynamics in marine ecosystems: A conceptual model

    PubMed Central

    Chen, Celia Y.; Hammerschmidt, Chad R.; Mason, Robert P.; Gilmour, Cynthia C.; Sunderland, Elsie M.; Greenfield, Ben K.; Buckman, Kate L.; Lamborg, Carl H.

    2013-01-01

    There is increasing interest and concern over the impacts of mercury (Hg) inputs to marine ecosystems. One of the challenges in assessing these effects is that the cycling and trophic transfer of Hg are strongly linked to other contaminants and disturbances. In addition to Hg, a major problem facing coastal waters is the impacts of elevated nutrient, particularly nitrogen (N), inputs. Increases in nutrient loading alter coastal ecosystems in ways that should change the transport, transformations and fate of Hg, including increases in fixation of organic carbon and deposition to sediments, decreases in the redox status of sediments and changes in fish habitat. In this paper we present a conceptual model which suggests that increases in loading of reactive N to marine ecosystems might alter Hg dynamics, decreasing bioavailabilty and trophic transfer. This conceptual model is most applicable to coastal waters, but may also be relevant to the pelagic ocean. We present information from case studies that both support and challenge this conceptual model, including marine observations across a nutrient gradient; results of a nutrient-trophic transfer Hg model for pelagic and coastal ecosystems; observations of Hg species, and nutrients from coastal sediments in the northeastern U.S.; and an analysis of fish Hg concentrations in estuaries under different nutrient loadings. These case studies suggest that changes in nutrient loading can impact Hg dynamics in coastal and open ocean ecosystems. Unfortunately none of the case studies is comprehensive; each only addresses a portion of the conceptual model and has limitations. Nevertheless, our conceptual model has important management implications. Many estuaries near developed areas are impaired due to elevated nutrient inputs. Widespread efforts are underway to control N loading and restore coastal ecosystem function. An unintended consequence of nutrient control measures could be to exacerbate problems associated with Hg

  4. A Multi-Agency Nutrient Dataset Used to Estimate Loads, Improve Monitoring Design, and Calibrate Regional Nutrient SPARROW Models

    USGS Publications Warehouse

    Saad, D.A.; Schwarz, G.E.; Robertson, D.M.; Booth, N.L.

    2011-01-01

    Stream-loading information was compiled from federal, state, and local agencies, and selected universities as part of an effort to develop regional SPAtially Referenced Regressions On Watershed attributes (SPARROW) models to help describe the distribution, sources, and transport of nutrients in streams throughout much of the United States. After screening, 2,739 sites, sampled by 73 agencies, were identified as having suitable data for calculating long-term mean annual nutrient loads required for SPARROW model calibration. These sites had a wide range in nutrient concentrations, loads, and yields, and environmental characteristics in their basins. An analysis of the accuracy in load estimates relative to site attributes indicated that accuracy in loads improve with increases in the number of observations, the proportion of uncensored data, and the variability in flow on observation days, whereas accuracy declines with increases in the root mean square error of the water-quality model, the flow-bias ratio, the number of days between samples, the variability in daily streamflow for the prediction period, and if the load estimate has been detrended. Based on compiled data, all areas of the country had recent declines in the number of sites with sufficient water-quality data to compute accurate annual loads and support regional modeling analyses. These declines were caused by decreases in the number of sites being sampled and data not being entered in readily accessible databases. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  5. The use of food consumption data in assessments of exposure to food chemicals including the application of probabilistic modelling.

    PubMed

    Lambe, Joyce

    2002-02-01

    Emphasis on public health and consumer protection, in combination with globalisation of the food market, has created a strong demand for exposure assessments of food chemicals. The food chemicals for which exposure assessments are required include food additives, pesticide residues, environmental contaminants, mycotoxins, novel food ingredients, packaging-material migrants, flavouring substances and nutrients. A wide range of methodologies exists for estimating exposure to food chemicals, and the method chosen for a particular exposure assessment is influenced by the nature of the chemical, the purpose of the assessment and the resources available. Sources of food consumption data currently used in exposure assessments range from food balance sheets to detailed food consumption surveys of individuals and duplicate-diet studies. The fitness-for-purpose of the data must be evaluated in the context of data quality and relevance to the assessment objective. Methods to combine the food consumption data with chemical concentration data may be deterministic or probabilistic. Deterministic methods estimate intakes of food chemicals that may occur in a population, but probabilistic methods provide the advantage of estimating the probability with which different levels of intake will occur. Probabilistic analysis permits the exposure assessor to model the variability (true heterogeneity) and uncertainty (lack of knowledge) that may exist in the exposure variables, including food consumption data, and thus to examine the full distribution of possible resulting exposures. Challenges for probabilistic modelling include the selection of appropriate modes of inputting food consumption data into the models. PMID:12002785

  6. The use of food consumption data in assessments of exposure to food chemicals including the application of probabilistic modelling.

    PubMed

    Lambe, Joyce

    2002-02-01

    Emphasis on public health and consumer protection, in combination with globalisation of the food market, has created a strong demand for exposure assessments of food chemicals. The food chemicals for which exposure assessments are required include food additives, pesticide residues, environmental contaminants, mycotoxins, novel food ingredients, packaging-material migrants, flavouring substances and nutrients. A wide range of methodologies exists for estimating exposure to food chemicals, and the method chosen for a particular exposure assessment is influenced by the nature of the chemical, the purpose of the assessment and the resources available. Sources of food consumption data currently used in exposure assessments range from food balance sheets to detailed food consumption surveys of individuals and duplicate-diet studies. The fitness-for-purpose of the data must be evaluated in the context of data quality and relevance to the assessment objective. Methods to combine the food consumption data with chemical concentration data may be deterministic or probabilistic. Deterministic methods estimate intakes of food chemicals that may occur in a population, but probabilistic methods provide the advantage of estimating the probability with which different levels of intake will occur. Probabilistic analysis permits the exposure assessor to model the variability (true heterogeneity) and uncertainty (lack of knowledge) that may exist in the exposure variables, including food consumption data, and thus to examine the full distribution of possible resulting exposures. Challenges for probabilistic modelling include the selection of appropriate modes of inputting food consumption data into the models.

  7. Dissolved Nutrient Retention Dynamics in River Networks: A Modeling Investigation of Transient Flow and Scale Effects

    SciTech Connect

    Ye, Sheng; Covino, Timothy P.; Sivapalan, Murugesu; Basu, Nandita; Li, Hongyi; Wang, Shaowen

    2012-06-30

    In this paper, we use a dynamic network flow model, coupled with a transient storage zone biogeochemical model, to simulate dissolved nutrient removal processes at the channel network scale. We have explored several scenarios in respect of the combination of rainfall variability, and the biological and geomorphic characteristics of the catchment, to understand the dominant controls on removal and delivery of dissolved nutrients (e.g., nitrate). These model-based theoretical analyses suggested that while nutrient removal efficiency is lower during flood events compared to during baseflow periods, flood events contribute significantly to bulk nutrient removal, whereas bulk removal during baseflow periods is less. This is due to the fact that nutrient supply is larger during flood events; this trend is even stronger in large rivers. However, the efficiency of removal during both periods decreases in larger rivers, however, due to (i) increasing flow velocities and thus decreasing residence time, and (ii) increasing flow depth, and thus decreasing nutrient uptake rates. Besides nutrient removal processes can be divided into two parts: in the main channel and in the hyporheic transient storage zone. When assessing their relative contributions the size of the transient storage zone is a dominant control, followed by uptake rates in the main channel and in the transient storage zone. Increasing size of the transient storage zone with downstream distance affects the relative contributions to nutrient removal of the water column and the transient storage zone, which also impacts the way nutrient removal rates scale with increasing size of rivers. Intra-annual hydrologic variability has a significant impact on removal rates at all scales: the more variable the streamflow is, compared to mean discharge, the less nutrient is removed in the channel network. A scale-independent first order uptake coefficient, ke, estimated from model simulations, is highly dependent on the

  8. Modeling Nutrient Release in the Tai Lake Basin of China: Source Identification and Policy Implications

    NASA Astrophysics Data System (ADS)

    Liu, Beibei; Liu, Heng; Zhang, Bing; Bi, Jun

    2013-03-01

    Because nutrient enrichment has become increasingly severe in the Tai Lake Basin of China, identifying sources and loads is crucial for watershed nutrient management. This paper develops an empirical framework to estimate nutrient release from five major sectors, which requires fewer input parameters and produces acceptable accuracy. Sectors included are industrial manufacturing, livestock breeding (industrial and family scale), crop agriculture, household consumption (urban and rural), and atmospheric deposition. Results show that in the basin (only the five sectors above), total nutrient loads of nitrogen (N) and phosphorus (P) into aquatic systems in 2008 were 33043.2 tons N a-1 and 5254.4 tons P a-1, and annual area-specific nutrient loads were 1.94 tons N km-2 and 0.31 tons P km-2. Household consumption was the major sector having the greatest impact (46 % in N load, 47 % in P load), whereas atmospheric deposition (18 %) and crop agriculture (15 %) sectors represented other significant proportions of N load. The load estimates also indicate that 32 % of total P came from the livestock breeding sector, making it the second largest phosphorus contributor. According to the nutrient pollution sectors, six best management practices are selected for cost-effectiveness analysis, and feasible options are recommended. Overall, biogas digester construction on industrial-scale farms is proven the most cost-effective, whereas the building of rural decentralized facilities is the best alternative under extreme financial constraint. However, the reduction potential, average monetary cost, and other factors such as risk tolerance of policy makers should all be considered in the actual decision-making process.

  9. Modeling nutrient release in the Tai Lake basin of China: source identification and policy implications.

    PubMed

    Liu, Beibei; Liu, Heng; Zhang, Bing; Bi, Jun

    2013-03-01

    Because nutrient enrichment has become increasingly severe in the Tai Lake Basin of China, identifying sources and loads is crucial for watershed nutrient management. This paper develops an empirical framework to estimate nutrient release from five major sectors, which requires fewer input parameters and produces acceptable accuracy. Sectors included are industrial manufacturing, livestock breeding (industrial and family scale), crop agriculture, household consumption (urban and rural), and atmospheric deposition. Results show that in the basin (only the five sectors above), total nutrient loads of nitrogen (N) and phosphorus (P) into aquatic systems in 2008 were 33043.2 tons N a(-1) and 5254.4 tons P a(-1), and annual area-specific nutrient loads were 1.94 tons N km(-2) and 0.31 tons P km(-2). Household consumption was the major sector having the greatest impact (46 % in N load, 47 % in P load), whereas atmospheric deposition (18 %) and crop agriculture (15 %) sectors represented other significant proportions of N load. The load estimates also indicate that 32 % of total P came from the livestock breeding sector, making it the second largest phosphorus contributor. According to the nutrient pollution sectors, six best management practices are selected for cost-effectiveness analysis, and feasible options are recommended. Overall, biogas digester construction on industrial-scale farms is proven the most cost-effective, whereas the building of rural decentralized facilities is the best alternative under extreme financial constraint. However, the reduction potential, average monetary cost, and other factors such as risk tolerance of policy makers should all be considered in the actual decision-making process.

  10. Short-Term Energy Outlook Model Documentation: Other Petroleum Products Consumption Model

    EIA Publications

    2011-01-01

    The other petroleum product consumption module of the Short-Term Energy Outlook (STEO) model is designed to provide U.S. consumption forecasts for 6 petroleum product categories: asphalt and road oil, petrochemical feedstocks, petroleum coke, refinery still gas, unfinished oils, and other miscvellaneous products

  11. Uniform modeling of bacterial colony patterns with varying nutrient and substrate

    NASA Astrophysics Data System (ADS)

    Schwarcz, Deborah; Levine, Herbert; Ben-Jacob, Eshel; Ariel, Gil

    2016-04-01

    Bacteria develop complex patterns depending on growth condition. For example, Bacillus subtilis exhibit five different patterns depending on substrate hardness and nutrient concentration. We present a unified integro-differential model that reproduces the entire experimentally observed morphology diagram at varying nutrient concentrations and substrate hardness. The model allows a comprehensive and quantitative comparison between experimental and numerical variables and parameters, such as colony growth rate, nutrient concentration and diffusion constants. As a result, the role of the different physical mechanisms underlying and regulating the growth of the colony can be evaluated.

  12. Large scale nutrient modelling using globally available datasets: A test for the Rhine basin

    NASA Astrophysics Data System (ADS)

    Loos, Sibren; Middelkoop, Hans; van der Perk, Marcel; van Beek, Rens

    2009-05-01

    SummaryNutrient discharge to coastal waters from rivers draining populated areas can cause vast algal blooms. Changing conditions in the drainage basin, like land use change, or climate induced changes in hydrology, may alter riverine nitrogen (N) and phosphorus (P) fluxes and further increase the pressure on coastal water quality. Several large scale models have been employed to quantify riverine nutrient fluxes on a yearly to decadal timescale. Seasonal variation of these fluxes, governed by internal nutrient transformations and attenuation, is often larger than the inter-annual variation and may contain crucial information on nutrient transfer through river basins and should therefore not be overlooked. In the last decade the increasing availability of global datasets at fine resolutions has enabled the modelling of multiple basins using a coherent dataset. Furthermore, the use of global datasets will aid to global change impact assessment. We developed a new model, RiNUX, to adequately simulate present and future river nutrient loads in large river basins. The RiNUX model captures the intra-annual variation at the basin scale in order to provide more accurate estimates of future nutrient loads in response to global change. With an incorporated dynamic sediment flux model, the particulate nutrient loads can be assessed. It is concluded that the RiNUX model provides a powerful, spatial and temporal explicit tool to estimate intra-annual variations in riverine nutrient loads in large river basins. The model was calibrated using the detailed RHIN dataset and its overall efficiency was tested using a coarser dataset GLOB for the Rhine basin. Using the RHIN dataset seasonal variable nutrient load at the river outlet can be satisfactorily modelled for both total N ( E = 0.50) and total P ( E = 0.47). The largest prediction errors occur in estimating high TN loads. When using the GLOB dataset, the model efficiency is lower for TN ( E = 0.12), due to overestimated

  13. Organic nutrient uptake by mycorrhizal fungi enhances ecosystem carbon storage: a model-based assessment.

    PubMed

    Orwin, Kate H; Kirschbaum, Miko U F; St John, Mark G; Dickie, Ian A

    2011-05-01

    Understanding the factors that drive soil carbon (C) accumulation is of fundamental importance given their potential to mitigate climate change. Much research has focused on the relationship between plant traits and C sequestration, but no studies to date have quantitatively considered traits of their mycorrhizal symbionts. Here, we use a modelling approach to assess the contribution of an important mycorrhizal fungal trait, organic nutrient uptake, to soil C accumulation. We show that organic nutrient uptake can significantly increase soil C storage, and that it has a greater effect under nutrient-limited conditions. The main mechanism behind this was an increase in plant C fixation and subsequent increased C inputs to soil through mycorrhizal fungi. Reduced decomposition due to increased nutrient limitation of saprotrophs also played a role. Our results indicate that direct uptake of nutrients from organic pools by mycorrhizal fungi could have a significant effect on ecosystem C cycling and storage. PMID:21395963

  14. Materials flow modeling of nutrient recycling in biodiesel production from microalgae.

    PubMed

    Rösch, Christine; Skarka, Johannes; Wegerer, Nadja

    2012-03-01

    Biodiesel production based on microalgae as feedstock is associated with a high demand of nutrients, respectively nitrogen and phosphorus. The production of 1l biodiesel requires between 0.23 and 1.55 kg nitrogen and 29-145 g of phosphorus depending of the cultivation conditions for microalgae. The supply of nutrients can be expected to severely limit the extent to which the production of biofuels from microalgae can be sustainably expanded. The nutrient demand can be reduced if the nutrients in the residual algae biomass after oil extraction are reused for algae cultivation. This modeling work illustrates that for the investigated process chains and scenarios the nutrient recycling rates are in the range from 30% to 90% for nitrogen and from 48% to 93% for phosphorus. The highest recycling values can be achieved by hydrothermal gasification of the oil-free residues.

  15. Effect of the method of preparation for consumption on calcium retention, calcium:phosphorus ratio, nutrient density and recommended daily allowance in fourteen vegetables.

    PubMed

    Słupski, Jacek; Gębczyński, Piotr; Korus, Anna; Lisiewska, Zofia

    2014-06-01

    The aim of this work was to evaluate calcium retention in 14 species of vegetable (from four usable groups). The material investigated consisted of raw and boiled fresh vegetables and two types of frozen product prepared for consumption after 12-month storage: one traditionally produced; the other obtained using the modified method (convenience food). The highest calcium content was found in leafy vegetables, followed (in descending order) by leguminous, root and brassica vegetables. The proportion by weight of Ca to P was highest in leafy vegetables and decreased with calcium retention despite the fact that levels of phosphorus were highest in leguminous and lowest in leafy vegetables. The nutrient density (ND%) of calcium for adults exceeded 100 for each individual vegetable species. The recommended daily allowance (RDA) percentage value varied between 23.04 (kale) and 1.46 (white cauliflower). Of the three types of product, ND and RDA values were generally greater in the frozen convenience products.

  16. Effect of the method of preparation for consumption on calcium retention, calcium:phosphorus ratio, nutrient density and recommended daily allowance in fourteen vegetables.

    PubMed

    Słupski, Jacek; Gębczyński, Piotr; Korus, Anna; Lisiewska, Zofia

    2014-06-01

    The aim of this work was to evaluate calcium retention in 14 species of vegetable (from four usable groups). The material investigated consisted of raw and boiled fresh vegetables and two types of frozen product prepared for consumption after 12-month storage: one traditionally produced; the other obtained using the modified method (convenience food). The highest calcium content was found in leafy vegetables, followed (in descending order) by leguminous, root and brassica vegetables. The proportion by weight of Ca to P was highest in leafy vegetables and decreased with calcium retention despite the fact that levels of phosphorus were highest in leguminous and lowest in leafy vegetables. The nutrient density (ND%) of calcium for adults exceeded 100 for each individual vegetable species. The recommended daily allowance (RDA) percentage value varied between 23.04 (kale) and 1.46 (white cauliflower). Of the three types of product, ND and RDA values were generally greater in the frozen convenience products. PMID:24467467

  17. Tree Nut Consumption Is Associated with Better Nutrient Adequacy and Diet Quality in Adults: National Health and Nutrition Examination Survey 2005–2010

    PubMed Central

    O’Neil, Carol E.; Nicklas, Theresa A.; Fulgoni, Victor L.

    2015-01-01

    Nutrient adequacy of tree nut consumers has not been examined. The National Health and Nutrition Examination Survey 2005–2010 data were used to assess the association of tree nut consumption by adults 19+ years (n = 14,386) with nutrient adequacy and diet quality. Covariate adjusted usual intake was determined using two 24-h dietary recalls and the National Cancer Institute method. Percentages of the consumption groups below the Estimated Average Requirement (EAR) or above the Adequate Intake (AI) were determined. Diet quality was determined using the Healthy Eating Index-2005 (HEI) score. Usual intake data showed consumers of tree nuts had a lower percentage (p < 0.0001) of the population below the EAR for vitamins A (22 ± 5 vs. 49 ± 1), E (38 ± 4 vs. 94 ± 0.4) and C (17 ± 4 vs. 44 ± 1); folate (2.5 ± 1.5 vs. 12 ± 0.6); calcium (26 ± 3 vs. 44 ± 1); iron (3 ± 0.6 vs. 9 ± 0.4); magnesium (8 ± 1 vs. 60 ± 1); and zinc (1.5 ± 1 vs. 13 ± 1). Tree nut consumers had a higher percentage (p < 0.0001) of the population above the AI for fiber (33 ± 3 vs. 4 ± 0.3) and potassium (12 ± 3 mg vs. 2 ± 0.2 mg). HEI-2005 total score was higher (p < 0.0001) in tree nut consumers (61 ± 0.7 vs. 52 ± 0.3) than non-consumers. Health professionals should encourage the use of tree nuts as part of a dietary approach to healthy eating. PMID:25599274

  18. Tree nut consumption is associated with better nutrient adequacy and diet quality in adults: National Health and Nutrition Examination Survey 2005-2010.

    PubMed

    O'Neil, Carol E; Nicklas, Theresa A; Fulgoni, Victor L

    2015-01-15

    Nutrient adequacy of tree nut consumers has not been examined. The National Health and Nutrition Examination Survey 2005-2010 data were used to assess the association of tree nut consumption by adults 19+ years (n = 14,386) with nutrient adequacy and diet quality. Covariate adjusted usual intake was determined using two 24-h dietary recalls and the National Cancer Institute method. Percentages of the consumption groups below the Estimated Average Requirement (EAR) or above the Adequate Intake (AI) were determined. Diet quality was determined using the Healthy Eating Index-2005 (HEI) score. Usual intake data showed consumers of tree nuts had a lower percentage (p < 0.0001) of the population below the EAR for vitamins A (22 ± 5 vs. 49 ± 1), E (38 ± 4 vs. 94 ± 0.4) and C (17 ± 4 vs. 44 ± 1); folate (2.5 ± 1.5 vs. 12 ± 0.6); calcium (26 ± 3 vs. 44 ± 1); iron (3 ± 0.6 vs. 9 ± 0.4); magnesium (8 ± 1 vs. 60 ± 1); and zinc (1.5 ± 1 vs. 13 ± 1). Tree nut consumers had a higher percentage (p < 0.0001) of the population above the AI for fiber (33 ± 3 vs. 4 ± 0.3) and potassium (12 ± 3 mg vs. 2 ± 0.2 mg). HEI-2005 total score was higher (p < 0.0001) in tree nut consumers (61 ± 0.7 vs. 52 ± 0.3) than non-consumers. Health professionals should encourage the use of tree nuts as part of a dietary approach to healthy eating.

  19. Linking nutrient loading and oxygen in the coastal ocean: A new global scale model

    NASA Astrophysics Data System (ADS)

    Reed, Daniel C.; Harrison, John A.

    2016-03-01

    Recent decades have witnessed an exponential spread of low-oxygen regions in the coastal ocean due at least in-part to enhanced terrestrial nutrient inputs. As oxygen deprivation is a major stressor on marine ecosystems, there is a great need to quantitatively link shifts in nutrient loading with changes in oxygen concentrations. To this end, we have developed and here describe, evaluate, and apply the Coastal Ocean Oxygen Linked to Benthic Exchange And Nutrient Supply (COOLBEANS) model, a first-of-its-kind, spatially explicit (with 152 coastal segments) model, global model of coastal oxygen and nutrient dynamics. In COOLBEANS, benthic oxygen demand (BOD) is calculated using empirical models for aerobic respiration, iron reduction, and sulfate reduction, while oxygen supply is represented by a simple parameterization of exchange between surface and bottom waters. A nutrient cycling component translates shifts in riverine nutrient inputs into changes in organic matter delivery to sediments and, ultimately, oxygen uptake. Modeled BOD reproduces observations reasonably well (Nash-Sutcliffe efficiency = 0.71), and estimates of exchange between surface and bottom waters correlate with stratification. The model examines sensitivity of bottom water oxygen to changes in nutrient inputs and vertical exchange between surface and bottom waters, highlighting the importance of this vertical exchange in defining the susceptibility of a system to oxygen depletion. These sensitivities along with estimated maximum hypoxic areas that are supported by present day nutrient loads are consistent with existing hypoxic regions. Sensitivities are put into context by applying historic changes in nitrogen loading observed in the Gulf of Mexico to the global coastal ocean, demonstrating that such loads would drive many systems anoxic or even sulfidic.

  20. Evaluation models for soil nutrient based on support vector machine and artificial neural networks.

    PubMed

    Li, Hao; Leng, Weijia; Zhou, Yibing; Chen, Fudi; Xiu, Zhilong; Yang, Dazuo

    2014-01-01

    Soil nutrient is an important aspect that contributes to the soil fertility and environmental effects. Traditional evaluation approaches of soil nutrient are quite hard to operate, making great difficulties in practical applications. In this paper, we present a series of comprehensive evaluation models for soil nutrient by using support vector machine (SVM), multiple linear regression (MLR), and artificial neural networks (ANNs), respectively. We took the content of organic matter, total nitrogen, alkali-hydrolysable nitrogen, rapidly available phosphorus, and rapidly available potassium as independent variables, while the evaluation level of soil nutrient content was taken as dependent variable. Results show that the average prediction accuracies of SVM models are 77.87% and 83.00%, respectively, while the general regression neural network (GRNN) model's average prediction accuracy is 92.86%, indicating that SVM and GRNN models can be used effectively to assess the levels of soil nutrient with suitable dependent variables. In practical applications, both SVM and GRNN models can be used for determining the levels of soil nutrient.

  1. Stressor-Response Models Relating Nutrient Enrichment to Algal Communities in Pacific Northwest Streams and Rivers

    NASA Astrophysics Data System (ADS)

    Sobota, D. J.; Hubler, S.; Paul, M. J.; Labiosa, R.

    2015-12-01

    Excessive algal growth in streams and rivers from nutrient enrichment can cause costly human health and environmental problems. As part of the US Environmental Protection Agency's Nutrient Scientific Technical Exchange Partnership and Support (N-STEPS) program, we have been developing stressor-response (S-R) models relating nutrients to attached algal (periphyton) communities to help prioritize monitoring for water quality impairments in Oregon (Pacific Northwest, USA) streams and rivers. Existing data from the state and neighboring states were compiled and standardized from the Oregon Department of Environmental Quality, US Environmental Protection Agency, and the US Geological Survey. To develop S-R models, algal community and biomass metrics were compared with nitrogen (N) and phosphorus (P) concentration data, including total, dissolved, and inorganic forms of these nutrients. In total, 928 paired algal-nutrient samples were compiled from the 8 Level-III Ecoregions occurring in Oregon. Relationships between algal biomass metrics and nutrient concentrations were weak, with only ash-free dry mass and standing stock of chlorophyll a showing slight positive relationships across gradients of total N and soluble reactive P concentrations, respectively. In contrast, metrics describing algal community composition, including percent diatoms and abundance of nutrient-sensitive species, showed very strong nonlinear relationships with total N or P concentrations. This suggests that data describing algal community composition can help identify specific nutrient stressors across environmentally-diverse streams and rivers in the Pacific Northwest. Future analyses will examine if nutrient-algal S-R models vary across different hydrological, physiographical, and ecological settings in the region.

  2. Application of Hierarchy Theory to Cross-Scale Hydrologic Modeling of Nutrient Loads

    EPA Science Inventory

    We describe a model called Regional Hydrologic Modeling for Environmental Evaluation 16 (RHyME2) for quantifying annual nutrient loads in stream networks and watersheds. RHyME2 is 17 a cross-scale statistical and process-based water-quality model. The model ...

  3. Determining ecoregional numeric nutrient criteria by stressor-response models in Yungui ecoregion lakes, China.

    PubMed

    Huo, Shouliang; Ma, Chunzi; Xi, Beidou; Tong, Zhonghua; He, Zhuoshi; Su, Jing; Wu, Fengchang

    2014-01-01

    The importance of developing numeric nutrient criteria has been recognized to protect the designated uses of water bodies from nutrient enrichment that is associated with broadly occurring levels of nitrogen/phosphorus pollution. The identification and estimation of stressor-response models in aquatic ecosystems has been shown to be useful in the determination of nutrient criteria. In this study, three methods based on stressor-response relationships were applied to determine nutrient criteria for Yungui ecoregion lakes with respect to total phosphorus (TP), total nitrogen (TN), and planktonic chlorophyll a (Chl a). Simple linear regression (SLR) models were established to provide an estimate of the relationship between a response variable and a stressor. Multiple linear regressions were used to simultaneously estimate the effect of TP and TN on Chl a. A morphoedaphic index (MEI) was applied to derive nutrient criteria using data from Yungui ecoregion lakes, which were considered as areas with less anthropogenic influences. Nutrient criteria, as determined by these three methods, showed broad agreement for all parameters. The ranges of numeric nutrient criteria for Yungui ecoregion lakes were determined as follows: TP 0.008-0.010 mg/L and TN 0.140-0.178 mg/L. The stressor-response analysis described will be of benefit to support countries in their numeric criteria development programs and to further the goal of reducing nitrogen/phosphorus pollution in China.

  4. A Geographic Information System approach to modeling nutrient and sediment transport

    SciTech Connect

    Levine, D.A.; Hunsaker, C.T.; Beauchamp, J.J.; Timmins, S.P.

    1993-02-01

    The objective of this study was to develop a water quality model to quantify nonpoint-source (NPS) pollution that uses a geographic information system (GIS) to link statistical modeling of nutrient and sediment delivery with the spatial arrangement of the parameters that drive the model. The model predicts annual nutrient and sediment loading and was developed, calibrated, and tested on 12 watersheds within the Lake Ray Roberts drainage basin in north Texas. Three physiographic regions are represented by these watersheds, and model success, as measured by the accuracy of load estimates, was compared within and across these regions.

  5. A mathematical model of water and nutrient transport in xylem vessels of a wheat plant.

    PubMed

    Payvandi, S; Daly, K R; Jones, D L; Talboys, P; Zygalakis, K C; Roose, T

    2014-03-01

    At a time of increasing global demand for food, dwindling land and resources, and escalating pressures from climate change, the farming industry is undergoing financial strain, with a need to improve efficiency and crop yields. In order to improve efficiencies in farming, and in fertiliser usage in particular, understanding must be gained of the fertiliser-to-crop-yield pathway. We model one aspect of this pathway; the transport of nutrients within the vascular tissues of a crop plant from roots to leaves. We present a mathematical model of the transport of nutrients within the xylem vessels in response to the evapotranspiration of water. We determine seven different classes of flow, including positive unidirectional flow, which is optimal for nutrient transport from the roots to the leaves; and root multidirectional flow, which is similar to the hydraulic lift process observed in plants. We also investigate the effect of diffusion on nutrient transport and find that diffusion can be significant at the vessel termini especially if there is an axial efflux of nutrient, and at night when transpiration is minimal. Models such as these can then be coupled to whole-plant models to be used for optimisation of nutrient delivery scenarios. PMID:24557938

  6. [Consumption of nutrients among the elderly living in Porto Alegre in the State of Rio Grande do Sul, Brazil: a population-based study].

    PubMed

    Venturini, Carina Duarte; Engroff, Paula; Sgnaolin, Vanessa; El Kik, Raquel Milani; Morrone, Fernanda Bueno; da Silva Filho, Irenio Gomes; De Carli, Geraldo Attilio

    2015-12-01

    A cross-sectional, population-based study was conducted on a random sample of 427 elderly individuals living in Porto Alegre, Brazil, to establish the nutrient consumption profile and verify its association with sociodemographic and health variables. Dietary intake was assessed using the 24-hour Food Recall Survey and the Dietetic Research Investigation technique. Seventy percent of the elderly respondents were women: 48.5% were between 60 and 69 years old; 68.8% had less than 8 years of schooling; 39% had a family income of between 2 and 5 minimum wages and 58.4% took no physical exercise. Hypertension was the most prevalent disease among the elderly and 54.9% were underweight. Men consumed more calories, protein, fiber, minerals and vitamins than women. Carbohydrate and calcium intake increases with advancing age, while zinc intake decreases. Physical exercise increased the intake of calories, magnesium, potassium and phosphorus. The higher the schooling the greater the intake of vitamins B6 and B12; the higher the family income, the greater the consumption of vitamin B6 and folic acid. The results show that there are nutritional deficiencies in the daily diet of the Brazilian elderly population, especially among women and individuals over 80 years of age. PMID:26691795

  7. [Consumption of nutrients among the elderly living in Porto Alegre in the State of Rio Grande do Sul, Brazil: a population-based study].

    PubMed

    Venturini, Carina Duarte; Engroff, Paula; Sgnaolin, Vanessa; El Kik, Raquel Milani; Morrone, Fernanda Bueno; da Silva Filho, Irenio Gomes; De Carli, Geraldo Attilio

    2015-12-01

    A cross-sectional, population-based study was conducted on a random sample of 427 elderly individuals living in Porto Alegre, Brazil, to establish the nutrient consumption profile and verify its association with sociodemographic and health variables. Dietary intake was assessed using the 24-hour Food Recall Survey and the Dietetic Research Investigation technique. Seventy percent of the elderly respondents were women: 48.5% were between 60 and 69 years old; 68.8% had less than 8 years of schooling; 39% had a family income of between 2 and 5 minimum wages and 58.4% took no physical exercise. Hypertension was the most prevalent disease among the elderly and 54.9% were underweight. Men consumed more calories, protein, fiber, minerals and vitamins than women. Carbohydrate and calcium intake increases with advancing age, while zinc intake decreases. Physical exercise increased the intake of calories, magnesium, potassium and phosphorus. The higher the schooling the greater the intake of vitamins B6 and B12; the higher the family income, the greater the consumption of vitamin B6 and folic acid. The results show that there are nutritional deficiencies in the daily diet of the Brazilian elderly population, especially among women and individuals over 80 years of age.

  8. Early sugar-sweetened beverage consumption frequency is associated with poor quality of later food and nutrient intake patterns among Japanese young children: the Osaka Maternal and Child Health Study.

    PubMed

    Okubo, Hitomi; Miyake, Yoshihiro; Sasaki, Satoshi; Tanaka, Keiko; Hirota, Yoshio

    2016-06-01

    Evidence from Western countries shows that higher consumption of sugar-sweetened beverages (SSBs) is associated with lower quality of young children's diets, but little is known about these relations in non-Western countries with relatively low consumption levels of SSBs. We hypothesized that SSB consumption in infancy would be associated with poor quality of later food and nutrient intake patterns among Japanese young children. The study subjects were 493 Japanese mother-child pairs from a prospective birth cohort study. Dietary data on children were collected from the mothers using self-administered questionnaires when the children were aged 16-24 months and 41-49 months. Multiple linear regression analyses were used to examine the relationships between SSB consumption frequency in infancy and later intake of foods and nutrients. At 16-24 months of age, more than half of the children (56.4%) consumed SSBs less than once a week, whereas 11.6% consumed SSBs at least once daily. More frequent consumption of SSBs in infancy was associated with higher intake of confectionaries and SSBs and lower intake of fruits and vegetables at 41-49 months of age. These associations were still evident after adjustment for maternal SSB consumption and socioeconomic status. At the nutrient level, SSB consumption frequency was positively associated with energy intake and inversely associated with intake of many nutrients, such as protein, dietary fiber, and most of the micronutrients examined. In conclusion, higher consumption frequency of SSBs at an early age is associated with poor quality of overall dietary intake among young Japanese children 1.5-2.5 years later. PMID:27188905

  9. Modeling brine and nutrient dynamics in Antarctic sea ice: The case of dissolved silica

    NASA Astrophysics Data System (ADS)

    Vancoppenolle, Martin; Goosse, Hugues; de Montety, Anne; Fichefet, Thierry; Tremblay, Bruno; Tison, Jean-Louis

    2010-02-01

    Sea ice ecosystems are characterized by microalgae living in brine inclusions. The growth rate of ice algae depends on light and nutrient supply. Here, the interactions between nutrients and brine dynamics under the influence of algae are investigated using a one-dimensional model. The model includes snow and ice thermodynamics with brine physics and an idealized sea ice biological component, characterized by one nutrient, namely, dissolved silica (DSi). In the model, DSi follows brine motion and is consumed by ice algae. Depending on physical ice characteristics, the brine flow is either advective, diffusive, or turbulent. The vertical profiles of ice salinity and DSi concentration are solutions of advection-diffusion equations. The model is configured to simulate the typical thermodynamic regimes of first-year Antarctic pack ice. The simulated vertical profiles of salinity and DSi qualitatively reproduce observations. Analysis of results highlights the role of convection in the lowermost 5-10 cm of ice. Convection mixes saline, nutrient-poor brine with comparatively fresh, nutrient-rich seawater. This implies a rejection of salt to the ocean and a flux of DSi to the ice. In the presence of growing algae, the simulated ocean-to-ice DSi flux increases by 0-115% compared to an abiotic situation. In turn, primary production and brine convection act in synergy to form a nutrient pump. The other important processes are the flooding of the surface by seawater and the percolation of meltwater. The former refills nutrients near the ice surface in spring. The latter, if present, tends to expell nutrients from the ice in summer.

  10. Water quality in Atlantic rainforest mountain rivers (South America): quality indices assessment, nutrients distribution, and consumption effect.

    PubMed

    Avigliano, Esteban; Schenone, Nahuel

    2016-08-01

    The South American Atlantic rainforest is a one-of-a-kind ecosystem considered as a biodiversity hotspot; however, in the last decades, it was intensively reduced to 7 % of its original surface. Water resources and water quality are one of the main goods and services this system provides to people. For monitoring and management recommendations, the present study is focused on (1) determining the nutrient content (nitrate, nitrite, ammonium, and phosphate) and physiochemical parameters (temperature, pH, electrical conductivity, turbidity, dissolved oxygen, and total dissolved solids) in surface water from 24 rainforest mountain rivers in Argentina, (2) analyzing the human health risk, (3) assessing the environmental distribution of the determined pollutants, and (4) analyzing water quality indices (WQIobj and WQImin). In addition, for total coliform bacteria, a dataset was used from literature. Turbidity, total dissolved solids, and nitrite (NO2 (-)) exceeded the guideline value recommended by national or international guidelines in several sampling stations. The spatial distribution pattern was analyzed by Principal Component Analysis and Factor Analysis (PCA/FA) showing well-defined groups of rivers. Both WQI showed good adjustment (R (2) = 0.89) and rated water quality as good or excellent in all sampling sites (WQI > 71). Therefore, this study suggests the use of the WQImin for monitoring water quality in the region and also the water treatment of coliform, total dissolved solids, and turbidity. PMID:27083909

  11. Water quality in Atlantic rainforest mountain rivers (South America): quality indices assessment, nutrients distribution, and consumption effect.

    PubMed

    Avigliano, Esteban; Schenone, Nahuel

    2016-08-01

    The South American Atlantic rainforest is a one-of-a-kind ecosystem considered as a biodiversity hotspot; however, in the last decades, it was intensively reduced to 7 % of its original surface. Water resources and water quality are one of the main goods and services this system provides to people. For monitoring and management recommendations, the present study is focused on (1) determining the nutrient content (nitrate, nitrite, ammonium, and phosphate) and physiochemical parameters (temperature, pH, electrical conductivity, turbidity, dissolved oxygen, and total dissolved solids) in surface water from 24 rainforest mountain rivers in Argentina, (2) analyzing the human health risk, (3) assessing the environmental distribution of the determined pollutants, and (4) analyzing water quality indices (WQIobj and WQImin). In addition, for total coliform bacteria, a dataset was used from literature. Turbidity, total dissolved solids, and nitrite (NO2 (-)) exceeded the guideline value recommended by national or international guidelines in several sampling stations. The spatial distribution pattern was analyzed by Principal Component Analysis and Factor Analysis (PCA/FA) showing well-defined groups of rivers. Both WQI showed good adjustment (R (2) = 0.89) and rated water quality as good or excellent in all sampling sites (WQI > 71). Therefore, this study suggests the use of the WQImin for monitoring water quality in the region and also the water treatment of coliform, total dissolved solids, and turbidity.

  12. One hundred percent orange juice consumption is associated with better diet quality, improved nutrient adequacy, and no increased risk for overweight/obesity in children.

    PubMed

    O'Neil, Carol E; Nicklas, Theresa A; Rampersaud, Gail C; Fulgoni, Victor L

    2011-09-01

    The purpose of this study was to examine the association of 100% orange juice (OJ) consumption by children 2 to 18 years of age (n = 7250) participating in the 2003 to 2006 National Health and Nutrition Examination Survey with intakes of select nutrients, MyPyramid food groups, diet quality-measured by the Healthy Eating Index-2005, weight status, and associated risk factors. The National Cancer Institute method was used to estimate the usual intake of 100% OJ consumption, selected nutrients, and MyPyramid food groups. Percentages of the population below the Estimated Average Requirement were determined. Covariate adjusted logistic regression was used to determine if consumers had a lower odds ratio of being overweight or obese. Usual per capita intake of 100% OJ was 1.7 oz/d. Among consumers, the usual intake of 100% OJ for children (n = 2183; 26.2% of population) was 10.2 oz/d. Consumers had higher (P < .05) energy intakes than nonconsumers (9148 ± 113 vs 8625 ± 473 kJ). However, there were no differences in weight or body mass index in consumers and nonconsumers, and there was no significant difference in the risk of being overweight or obese between consumers and nonconsumers (odds ratio, 0.86; 95% confidence interval, 0.70-1.05). Compared with nonconsumers, consumers had a higher (P < .01) percentage (% ± SE) of the population meeting the Estimated Average Requirement for vitamin A (19.6 ± 2.0 vs 30.2 ± 1.4), vitamin C (0.0 ± 0.0 vs 29.2 ± 1.2), folate (1.3 ± 0.3 vs 5.1 ± 0.6), and magnesium (25.5 ± 2.0 vs 39.0 ± 11). The Healthy Eating Index-2005 was significantly (P < .01) higher in consumers (52.4 ± 0.4 vs 48.5 ± 0.3). Consumers also had higher intakes of total fruit, fruit juice, and whole fruit. Moderate consumption of 100% OJ should be encouraged in children as a component of a healthy diet.

  13. Sensitivity of Hypoxia Predictions for the Northern Gulf of Mexico to Sediment Oxygen Consumption and Model Nesting

    NASA Astrophysics Data System (ADS)

    Fennel, Katja; Hu, Jiatang; Laurent, Arnaud; Marta-Almeida, Martinho; Hetland, Robert

    2014-05-01

    Interannual variations of the hypoxic area that develops every summer over the Texas-Louisiana Shelf are large. The 2008 Action Plan put forth by an alliance of multiple state and federal agencies and tribes calls for a decrease of the hypoxic area through nutrient management in the watershed. Realistic models help build mechanistic understanding of the processes underlying hypoxia formation and are thus indispensable for devising efficient nutrient reduction strategies. Here we present such a model, evaluate its hypoxia predictions against monitoring observations and assess the sensitivity of hypoxia predictions to model resolution, variations in sediment oxygen consumption and choice of physical horizontal boundary conditions. We find that hypoxia predictions on the shelf are very sensitive to the parameterization of sediment oxygen consumption, a result of the fact that hypoxic conditions are restricted to a relatively thin layer above the bottom over most of the shelf. We also show that the strength of vertical stratification is an important predictor of oxygen concentration in bottom waters and that modification of physical horizontal boundary conditions can have a large effect on hypoxia predictions.

  14. The Federal Highway Administration Gasohol Consumption Estimation Model

    SciTech Connect

    Hwang, HL

    2003-08-28

    The Federal Highway Administration (FHWA) is responsible for estimating the portion of Federal highway funds attributable to each State. The process involves use of State-reported data (gallons) and a set of estimation models when accurate State data is unavailable. To ensure that the distribution of funds is equitable, FHWA periodically reviews the estimation models. Estimation of the use of gasohol is difficult because of State differences in the definition of gasohol, inability of many States to separate and report gasohol usage from other fuel types, changes in fuel composition in nonattainment areas to address concerns over the use of certain fuel additives, and the lack of a valid State-level surrogate data set for gasohol use. Under the sponsorship of FHWA, Oak Ridge National Laboratory (ORNL) reviewed the regression-based gasohol estimation model that has been in use for several years. Based on an analytical assessment of that model and an extensive review of potential data sets, ORNL developed an improved rule-based model. The new model uses data from Internal Revenue Service, Energy Information Administration, Environmental Protection Agency, Department of Energy, ORNL, and FHWA sources. The model basically consists of three parts: (1) development of a controlled total of national gasohol usage, (2) determination of reliable State gasohol consumption data, and (3) estimation of gasohol usage for all other States. The new model will be employed for the 2004 attribution process. FHWA is currently soliciting comments and inputs from interested parties. Relevant data, as identified, will be pursued and refinements will be made by the research team if warranted.

  15. Regional scale nutrient modelling: exports to the Great Barrier Reef World Heritage Area.

    PubMed

    McKergow, Lucy A; Prosser, Ian P; Hughes, Andrew O; Brodie, Jon

    2005-01-01

    Clearing of native vegetation and replacement with cropping and grazing systems has increased nutrient exports to the Great Barrier Reef (GBR) to a level many times the natural rate. We present a technique for modelling nutrient transport, based on material budgets of river systems, and use it to identify the patterns and sources of nutrients exported. The outputs of the model can then be used to help prioritise catchment areas and land uses for management and assess various management options. Hillslope erosion is the largest source of particulate nutrients because of its dominance as a sediment source and the higher nutrient concentrations on surface soils. Dissolved nutrient fractions contribute 30% of total nitrogen and 15% of total phosphorus inputs. Spatial patterns show the elevated dissolved inorganic nitrogen export in the wetter catchments, and the dominance of particulate N and P from soil erosion in coastal areas. This study has identified catchments with high levels of contribution to exports and targeting these should be a priority.

  16. Improved Hypoxia Modeling for Nutrient Control Decisions in the Gulf of Mexico

    NASA Technical Reports Server (NTRS)

    Habib, Shaid; Pickering, Ken; Tzortziou, Maria; Maninio, Antonio; Policelli, Fritz

    2010-01-01

    As required by the Harmful Algal Bloom and Hypoxia Research Control Act of 1998, the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force issued the 2001 Gulf Hypoxia Action Plan (updated in 2008). In response to the Gulf Hypoxia Action Plan of 2001 (updated in 2008), the EPA Gulf of Mexico Hypoxia Modeling and Monitoring Project has established a detailed model for the Mississippi-Attchafalaya River Basin which provides a capability to forecast the multi-source nutrient loading to the Gulf and the subsequent bio-geochemical processes leading to hypoxic conditions and subsequent effects on Gulf habitats and fisheries. The primary purpose of the EPA model is to characterize the impacts of nutrient management actions, or proposed actions on the spatial and temporal characteristics of the Gulf hypoxic zone. The model is expected to play a significant role in determining best practices and improved strategies for incentivizing nutrient reduction strategies, including installation of on-farm structures to reduce sediment and nutrient runoff, use of cover crops and other agricultural practices, restoration of wetlands and riparian buffers, improved waste water treatment and decreased industrial nitrogen emissions. These decisions are currently made in a fragmented way by federal, state, and local agencies, using a variety of small scale models and limited data. During the past three years, EPA has collected an enormous amount of in-situ data to be used in the model. We believe that the use of NASA satellite data products in the model and for long term validation of the model has the potential to significantly increase the accuracy and therefore the utility of the model for the decision making described above. This proposal addresses the Gulf of Mexico Alliance (GOMA) priority issue of reductions in nutrient inputs to coastal ecosystem. It further directly relates to water quality for healthy beaches and shellfish beds and wetland and coastal conservation

  17. A Poroelastic Model Describing Nutrient Transport and Cell Stresses Within a Cyclically Strained Collagen Hydrogel

    PubMed Central

    Vaughan, Benjamin L.; Galie, Peter A.; Stegemann, Jan P.; Grotberg, James B.

    2013-01-01

    In the creation of engineered tissue constructs, the successful transport of nutrients and oxygen to the contained cells is a significant challenge. In highly porous scaffolds subject to cyclic strain, the mechanical deformations can induce substantial fluid pressure gradients, which affect the transport of solutes. In this article, we describe a poroelastic model to predict the solid and fluid mechanics of a highly porous hydrogel subject to cyclic strain. The model was validated by matching the predicted penetration of a bead into the hydrogel from the model with experimental observations and provides insight into nutrient transport. Additionally, the model provides estimates of the wall-shear stresses experienced by the cells embedded within the scaffold. These results provide insight into the mechanics of and convective nutrient transport within a cyclically strained hydrogel, which could lead to the improved design of engineered tissues. PMID:24209865

  18. Changes of Dietary Pattern, Food Choice, Food Consumption, Nutrient Intake and Body Mass Index of Korean American College Students with Different Length of Residence in the Los Angeles Areas

    ERIC Educational Resources Information Center

    Kim, Nam; Tam, Chick F.; Poon, George; Lew, Polong; Kim, Samuel Saychang; Kim, James C.; Kim, Rachel Byungsook

    2010-01-01

    This study was to investigate how dietary pattern, food choice, food consumption, nutrient intake and body mass index (BMI) vary with length of residence for Korean American college students. The respondents were 60 Korean American residents living in the Los Angeles Area. They were divided into two groups based on the length of stay in the U.S.:…

  19. Nutrient Intakes: Individuals in 48 States, Year 1977-78. Nationwide Food Consumption Survey 1977-78. Report No. I-2.

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC.

    This report presents 3-day nutrient intake data for about 36,100 individuals in 48 states. Data are provided in 157 tables, and results are summarized in the text. The contribution of 14 food groups to intakes of food energy and 14 nutrients are presented. Also included are the average intakes of food energy and nutrients, the nutrient densities…

  20. Hybrid Mice as Genetic Models of High Alcohol Consumption

    PubMed Central

    Ozburn, A. R.; Walker, D.; Ahmed, S.; Belknap, J. K.; Harris, R. A.

    2011-01-01

    We showed that F1 hybrid genotypes may provide a broader variety of ethanol drinking phenotypes than the inbred progenitor strains used to create the hybrids (Blednov et al. in Alcohol Clin Exp Res 29:1949–1958–2005). To extend this work, we characterized alcohol consumption as well as intake of other tastants (saccharin, quinine and sodium chloride) in five inbred strains of mice (FVB, SJL, B6, BUB, NZB) and in their reciprocal F1 hybrids with B6 (FVBxB6; B6xFVB; NZBxB6; B6xNZB; BUBxB6; B6xBUB; SJLxB6; B6xSJL). We also compared ethanol intake in these mice for several concentrations before and after two periods of abstinence. F1 hybrid mice derived from the crosses of B6 and FVB and also B6 and SJL drank higher levels of ethanol than their progenitor strains, demonstrating overdominance for two-bottle choice drinking test. The B6 and NZB hybrid showed additivity in two-bottle choice drinking, whereas the hybrid of B6 and BUB demonstrated full or complete dominance. Genealogical origin, as well as non-alcohol taste preferences (sodium chloride), predicted ethanol consumption. Mice derived from the crosses of B6 and FVB showed high sustained alcohol preference and the B6 and NZB hybrids showed reduced alcohol preference after periods of abstinence. These new genetic models offer some advantages over inbred strains because they provide high, sustained, alcohol intake, and should allow mapping of loci important for the genetic architecture of these traits. PMID:19798565

  1. Modelling combined effects of nutrients and toxicants in a branch of the Rhine Delta

    SciTech Connect

    Kramer, P.R.G.; Nijs, A.C.M. de; Aldenberg, T.

    1995-12-31

    A model is presented in which fate and effects of both nutrients and toxicants are combined at the level of phytoplankton and zooplankton in a river system including its sedimentation area. Within water quality modelling emphasis has been on either eutrophication or on toxic fates. Eutrophication research mainly focuses on the relationship between nutrients and water quality parameters. Ecotoxicological studies on the other hand aim either at describing fate of toxic substances or estimating biological effects on or below organism level on the basis of dose-effect experiments. However, an integrated approach linking fate and effects of nutrients and toxic substances on the ecosystem level is demanded to understand the behavior of natural systems exposed to a mix of compounds. The model describes a branch of the river Rhine, the river IJssel, with its sedimentation areas, lake Ketelmeer and lake IJsselmeer, which have suffered severely from high inputs of both nutrients and heavy metals in the past. Only from the seventies onward international sanitation programs have significantly improved the situation. Despite the improvements further actions are required because the problems of high chlorophyll levels as well as high loading of metals remain. It is shown that nutrients may induce an increase in phytoplankton biomass due to less efficient zooplankton grazing. Model results show that in order to change the present state of eutrophication also the input of xenobiotic substances affecting the zooplankton must be decreased.

  2. Short-Term Energy Outlook Model Documentation: Electricity Generation and Fuel Consumption Models

    EIA Publications

    2014-01-01

    The electricity generation and fuel consumption models of the Short-Term Energy Outlook (STEO) model provide forecasts of electricity generation from various types of energy sources and forecasts of the quantities of fossil fuels consumed for power generation. The structure of the electricity industry and the behavior of power generators varies between different areas of the United States. In order to capture these differences, the STEO electricity supply and fuel consumption models are designed to provide forecasts for the four primary Census regions.

  3. Modeling energy consumption in the Defense Logistics Agency. Final report, November 1986-December 1987

    SciTech Connect

    Hobson, J.J.

    1988-05-01

    The Defense Logistics Agency (DLA) Office of Installation Services and Environmental Protection was tasked with developing goals for energy consumption at each of the DLA-managed facilities. These goals could be based on factors that beyond the control of the organization and can vary from month to month, such as weather conditions and workload. This report presents the results of an analysis that mathematically modeled energy consumption and then attempted to use these models to assist in setting consumption goals for the agency. The DLA facilities identified the factors they considered to be predictors of energy consumption. Three years of monthly data were submitted for each factor. The data were screened to identify possible problems and to determine which factors had some relationship with energy consumption. Regression models were developed to predict total consumption, electric consumption, and non-electric consumption at each location. These models showed a definite relationship between weather and workload factors and energy consumption. However, the models were not accurate enough to be used to set consumption goals in DLA due to the impact of extraneous factors that were not quantifiable. Goals for energy consumption should be flexible to allow changes when unusual weather or workload conditions exist. However, these goals cannot be derived through a precise mathematical formula given the existing detail of available data.

  4. An empirical model for estimating annual consumption by freshwater fish populations

    USGS Publications Warehouse

    Liao, H.; Pierce, C.L.; Larscheid, J.G.

    2005-01-01

    Population consumption is an important process linking predator populations to their prey resources. Simple tools are needed to enable fisheries managers to estimate population consumption. We assembled 74 individual estimates of annual consumption by freshwater fish populations and their mean annual population size, 41 of which also included estimates of mean annual biomass. The data set included 14 freshwater fish species from 10 different bodies of water. From this data set we developed two simple linear regression models predicting annual population consumption. Log-transformed population size explained 94% of the variation in log-transformed annual population consumption. Log-transformed biomass explained 98% of the variation in log-transformed annual population consumption. We quantified the accuracy of our regressions and three alternative consumption models as the mean percent difference from observed (bioenergetics-derived) estimates in a test data set. Predictions from our population-size regression matched observed consumption estimates poorly (mean percent difference = 222%). Predictions from our biomass regression matched observed consumption reasonably well (mean percent difference = 24%). The biomass regression was superior to an alternative model, similar in complexity, and comparable to two alternative models that were more complex and difficult to apply. Our biomass regression model, log10(consumption) = 0.5442 + 0.9962??log10(biomass), will be a useful tool for fishery managers, enabling them to make reasonably accurate annual population consumption predictions from mean annual biomass estimates. ?? Copyright by the American Fisheries Society 2005.

  5. Nutrient inputs to the Laurentian Great Lakes by source and watershed estimated using SPARROW watershed models

    USGS Publications Warehouse

    Robertson, Dale M.; Saad, David A.

    2011-01-01

    Nutrient input to the Laurentian Great Lakes continues to cause problems with eutrophication. To reduce the extent and severity of these problems, target nutrient loads were established and Total Maximum Daily Loads are being developed for many tributaries. Without detailed loading information it is difficult to determine if the targets are being met and how to prioritize rehabilitation efforts. To help address these issues, SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed for estimating loads and sources of phosphorus (P) and nitrogen (N) from the United States (U.S.) portion of the Great Lakes, Upper Mississippi, Ohio, and Red River Basins. Results indicated that recent U.S. loadings to Lakes Michigan and Ontario are similar to those in the 1980s, whereas loadings to Lakes Superior, Huron, and Erie decreased. Highest loads were from tributaries with the largest watersheds, whereas highest yields were from areas with intense agriculture and large point sources of nutrients. Tributaries were ranked based on their relative loads and yields to each lake. Input from agricultural areas was a significant source of nutrients, contributing ∼33-44% of the P and ∼33-58% of the N, except for areas around Superior with little agriculture. Point sources were also significant, contributing ∼14-44% of the P and 13-34% of the N. Watersheds around Lake Erie contributed nutrients at the highest rate (similar to intensively farmed areas in the Midwest) because they have the largest nutrient inputs and highest delivery ratio.

  6. Applied coastal biogeochemical modelling to quantify the environmental impact of fish farm nutrients and inform managers

    NASA Astrophysics Data System (ADS)

    Wild-Allen, Karen; Herzfeld, Mike; Thompson, Peter A.; Rosebrock, Uwe; Parslow, John; Volkman, John K.

    2010-04-01

    A 3D biogeochemical model is validated against regional observations and used to quantify the fluxes and transformations of natural and anthropogenic nutrients in an oligotrophic marine channel and micro-tidal estuary in southern Tasmania. The model reproduces the seasonal cycle of pelagic phytoplankton biomass and dissolved inorganic nutrient concentrations observed in 2002 and is not excessively sensitive to the parameterization of the key biogeochemical processes of phytoplankton light absorption, zooplankton grazing or denitrification. Simulations indicate that in 2002, 66% of total nitrogen influx to the region was supplied from marine sources, 20% from rivers and 14% from salmon farms operating in the region. Fish farm loads of labile dissolved and particulate nitrogen have greatest impact on water quality in summer and autumn when they supply labile nutrient to seasonally depleted surface waters and fuel additional phytoplankton growth. Bays in the northern part of the region are more vulnerable to farm nutrient enrichment due, in part, to the residual northward circulation. It is estimated that in 2002 12% of the region had changed from oligotrophic to mesotrophic status due to salmon farm nutrient enrichment. Analysis of a future scenario simulation with 3 fold increase in farm loads quantified the spatial and temporal impact of farms on water quality and indicated that mesotrophic conditions could extend to 54% of the region. Statistical summaries and visualisation methods were used to communicate model results to stakeholders. Management action has been taken to limit future fish farm loads into the region and implement an environmental monitoring program.

  7. A multiple-realizations chance-constrained model for optimizing nutrient removal in constructed wetlands

    NASA Astrophysics Data System (ADS)

    Ng, Tze Ling; Eheart, J. Wayland

    2008-04-01

    High nutrient loads in surface waters are a cause of hypoxia in coastal ecosystems. Constructed wetlands offer a means of nutrient removal, but their design is complicated by environmental fluctuations. In the present work, a chance-constrained model is developed on the basis of satisfying performance constraints for a subset of the period of hydrologic and meteorological record. The model incorporates a nonsteady state wetland model and is used to determine the most cost-efficient wetland design given the nutrient removal requirements. Three candidate wetlands are considered. For two of them a comparison is made between operating the wetlands individually versus operating them concurrently. Results show that the factors limiting wetland performance are low flow availability and low inflow nutrient concentrations. Further, for the case considered, a two-wetland design is found to be more cost-effective than a single-wetland design. On average, wetlands have huge potential for nutrient removal but have a higher risk of failure than conventional treatment and could, under unfavorable conditions, be more expensive.

  8. A Numerical Analysis Model for the Interpretation of In Vivo Platelet Consumption Data

    PubMed Central

    Strom, Ted S.

    2013-01-01

    Unlike anemias, most thrombocytopenias cannot be separated into those due to impaired production and those due to accelerated consumption. While rapid clearance of labeled platelets from the bloodstream can be followed in thrombocytopenic individuals, no model exists for quantitatively inferring from autologous or allogeneic platelet consumption data what changes in random consumption, lifespan dependent consumption, and platelet production rate may have caused the thrombocytopenia. Here we describe a numerical analysis model which resolves these issues. The model applies three parameter values (a random consumption rate constant, a lognormally-distributed platelet lifespan, and the standard deviation of the latter) to a matrix comprising a series of platelet cohorts which are sequentially produced and fractionally consumed in a series of time intervals. The cohort platelet counts achieved after equilibration of production and consumption both enumerate the population age distribution and sum to the population platelet count. Continued platelet consumption after production is halted then serves to model in vivo platelet consumption data, with consumption rate in the first such interval defining the equilibrium platelet production rate. We use a least squares fitting procedure to find parameter values which best fit observed platelet consumption data obtained in WT and thrombocytopenic WASP(-) mice. Equilibrium platelet age distributions are then ‘grafted’ into the matrix to allow modeling of the consumption of WT platelets in WASP(-) recipients, and vice versa. The optimal parameter values obtained indicate that random WT platelet consumption accounts for a larger fraction of platelet turnover than was previously suspected. Platelet WASP deficiency accelerates random consumption, and a trans effect of recipient WASP deficiency contributes to this. Application of the model to clinical data will allow distinctions to be made between thrombocytopenias due

  9. The effects of modeling dietary restraint on food consumption: do restrained models promote restrained eating?

    PubMed

    Rotenberg, Ken J; Carte, Laura; Speirs, Amanda

    2005-01-01

    Sixty-nine female undergraduates completed the restraint scale, a dieting checklist, and the Eating Attribution Style Questionnaire (EASQ). The participants were exposed either to no model, a peer model who behaviorally demonstrated dietary restraint, or a peer model who behaviorally and verbally demonstrated dietary restraint. The participants had an opportunity to consume food as part of a taste test. The findings revealed that attribution style, but not restraint or current dieting status, moderated the effects of exposure to the peer models. Females who had an internal attribution style for indulgent food consumption decreased their consumption of food as a function of the dietary restraint of the models, whereas females who had an external attribution style for indulgent food consumption increased their consumption of food as a function of the dietary restraint of the models. The latter disinhibitory effect was attributed to negative social comparison and learned helplessness. The results supported the conclusion that the effectiveness of modeling dietary restraint is dependent on the attribution style of the observers. PMID:15567113

  10. Bioclogging of dune sediments by coupled nutrient transport and microbial evolution: a numerical modeling study

    NASA Astrophysics Data System (ADS)

    Boano, Fulvio; Ridolfi, Luca; Packman, Aaron; Vidali, Cristina

    2014-05-01

    Streambeds are biogeochemical hotspots for a number of reactions that influence the fate of nutrients in streams and groundwater and that are performed by microorganisms attached to the hyporheic sediments. It is well known that in nutrient-enriched streams the metabolic activity of hyporheic microbes relies on water-borne solutes that are supplied by water exchanged with the stream. However, microbes also exert feedbacks on nutrient fluxes through the process of bioclogging, i.e., the reduction of water-filled pore volume and sediment permeability caused by biofilm growth and gas production. Unfortunately, the present understanding of this process is limited by the difficulty of data collection within streambed sediments. In order to better understand the dynamics of bioclogging, we have performed a numerical modeling study on the coupling between water fluxes, nutrient reactions, and permeability variations due to microbial growth. We have updated a previously published hydro-biogeochemical model with the addition of two microbial components representing autotrophic (nitrifying) bacteria and heterotrophic (facultative aerobic) bacteria. We assume that biofilm grows and occupies pore space, thus altering hydraulic conductivity and modifying the fluxes of water and nutrients which support microbial metabolism. The simulation results show that the system eventually attains an equilibrium between microbial growth and nutrient fluxes that is characterized by a vertical stratification of the microbial species and by a strong reduction of permeability near the stream-sediment interface. These findings denote the existence of an equilibrium configuration and provide insights on how microbial reaction rates are constrained by sediment properties, hydrodynamic factors, and nutrient availability.

  11. Hydrological management for improving nutrient assimilative capacity in plant-dominated wetlands: A modelling approach.

    PubMed

    Xu, Zhihao; Yang, Zhifeng; Yin, Xinan; Cai, Yanpeng; Sun, Tao

    2016-07-15

    Wetland eutrophication is a global environmental problem. Besides reducing pollutant emissions, improving nutrient assimilative capacity in wetlands is also significant for preventing eutrophication. Hydrological management can improve nutrient assimilative capacity in wetlands through physical effects on the dilution capacity of water body and ecological effects on wetland nutrient cycles. The ecological effects are significant while were rarely considered in previous research. This study focused on the ecological effects of hydrological management on two crucial nutrient removal processes, plant uptake and biological denitrification, in plant-dominated wetlands. A dual-objective optimization model for hydrological management was developed to improve wetland nitrogen and phosphorus assimilative capacities, using upstream reservoir release as water regulating measure. The model considered the interactions between ecological processes and hydrological cycles in wetlands, and their joint effects on nutrient assimilative capacity. Baiyangdian Wetland, the largest freshwater wetland in northern China, was chosen as a case study. The results found that the annual total assimilative capacity of nitrogen (phosphorus) was 4754 (493) t under the optimal scheme for upstream reservoir operation. The capacity of nutrient removal during the summer season accounted for over 80% of the annual total removal capacity. It was interesting to find that the relationship between water inflow and nutrient assimilative capacity in a plant-dominated wetland satisfied a dose-response relationship commonly describing the response of an organism to an external stressor in the medical field. It illustrates that a plant-dominated wetland shows similar characteristics to an organism. This study offers a useful tool and some fresh implications for future management of wetland eutrophication prevention. PMID:27085151

  12. Predictive modeling of transient storage and nutrient uptake: Implications for stream restoration

    USGS Publications Warehouse

    O'Connor, Ben L.; Hondzo, Miki; Harvey, Judson

    2010-01-01

    This study examined two key aspects of reactive transport modeling for stream restoration purposes: the accuracy of the nutrient spiraling and transient storage models for quantifying reach-scale nutrient uptake, and the ability to quantify transport parameters using measurements and scaling techniques in order to improve upon traditional conservative tracer fitting methods. Nitrate (NO3–) uptake rates inferred using the nutrient spiraling model underestimated the total NO3– mass loss by 82%, which was attributed to the exclusion of dispersion and transient storage. The transient storage model was more accurate with respect to the NO3– mass loss (±20%) and also demonstrated that uptake in the main channel was more significant than in storage zones. Conservative tracer fitting was unable to produce transport parameter estimates for a riffle-pool transition of the study reach, while forward modeling of solute transport using measured/scaled transport parameters matched conservative tracer breakthrough curves for all reaches. Additionally, solute exchange between the main channel and embayment surface storage zones was quantified using first-order theory. These results demonstrate that it is vital to account for transient storage in quantifying nutrient uptake, and the continued development of measurement/scaling techniques is needed for reactive transport modeling of streams with complex hydraulic and geomorphic conditions.

  13. How to find information on national food and nutrient consumption surveys across Europe: systematic literature review and questionnaires to selected country experts are both good strategies.

    PubMed

    Blanquer, Maria; García-Alvarez, Alicia; Ribas-Barba, Lourdes; Wijnhoven, Trudy M A; Tabacchi, Garden; Gurinovic, Mirjana; Serra-Majem, Lluís

    2009-07-01

    The present research was conducted within the framework of the EURopean micronutrient RECommendations Aligned project. In order to identify the best practice in assessing nutrient intakes, a search strategy for collecting data from national food consumption surveys/studies in Europe was developed. Systematic literature searches were carried out on twenty-eight European and the four European Free Trade Association countries. A questionnaire was also sent to two to five experts in each country. Systematic reviews using PubMed yielded 12 703 abstracts that were reduced to 200 studies using inclusion and exclusion criteria. Similarly, a search of ministry web sites yielded 3033 hits, and subsequently reduced to nine surveys. Belgium, France, Germany, Ireland, Sweden, Spain and the United Kingdom were the countries with most data and Slovenia and Liechtenstein were those with the least. Seventy-eight expert questionnaires were obtained from all countries except for Liechtenstein, Luxembourg and Slovakia. Detailed results and references are given. A systematic search and questionnaires are equally good at identifying national surveys across countries. Literature searching provides globally accessible and objective information albeit limited, whereas the questionnaire provides information that, depending upon responders, can be more complete. A combination of both strategies is recommended.

  14. Calibration models for electromagnetic induction methods to assess nutrient accumulation beneath confined livestock areas.

    PubMed

    Cordeiro, Marcos R C; Ranjan, R Sri; Ferguson, Ian J

    2011-01-01

    Nutrient accumulation in soils beneath confined livestock areas is a potential source of groundwater contamination. Electromagnetic induction (EMI) has become a practical method to assess nutrient content, with multiple linear regression (MLR) as the statistical method often employed to translate EMI readings into nutrient content. The purpose of this research is to compare and contrast the performance of spatially referenced MLR models that include secondary, 'easy-to-acquire' predictor variables such as spatial coordinate locations, soil water content and elevation information with MLR models based solely on EMI readings. Six feedlot areas were surveyed with an EM38 conductivity meter and between 6 and 12 sites at each feedlot were sampled at five different depths. The electrical conductivity (EC(e)), nitrate (NO3-) and phosphate (PO4(3-)) concentrations were measured and used as response variables. Analyses were performed using two different approaches: the response variables in individual layers and response variables by combining the layers within the soil profile. The results of both MLR methods were comparable in most instances because the models preferentially incorporated predictors derived from EM38 readings. Differences between the models were more evident when predicting NO3- and PO4(3-), even though prediction of these two analytes by either method was generally poor. Combined profile analysis was more effective for defining nutrient build-up because by-layer analysis gave non-significant or poor models in many instances.

  15. Modeling the Impact of Landscape Variability on Nutrient and Pesticide Dynamics in CEAP Watersheds

    NASA Astrophysics Data System (ADS)

    Saia, S. M.; Steenhuis, T. S.; Easton, Z. M.; Boll, J.; Brooks, E. S.

    2010-12-01

    Keywords: water quality, best management practices, runoff The effectiveness of agricultural conservation strategies for reducing soil, nutrient, and pesticide transport varies among landscape type and climate. For instance, a riparian buffer may reduce phosphorous loading to a Northeastern stream but fail to have the same impact on a stream in the Midwest. We propose a model based on readily available input data that can be used to prioritize the implementation of agricultural practices across a range of landscapes. Because areas generating overland flow are more prone to nutrient and pesticide transport, new management tools must accurately predict surface and subsurface flows. A modified version of the process-based Water Erosion Prediction Project (WEPP) model was developed to more accurately estimate surface and subsurface flows as well as sediment, nutrient, and pesticide transport from saturated and unsaturated hill slopes. We compare model results to available nutrient transport data from 13 USDA funded Conservation Effects Assessment Project (CEAP) watersheds. Core objectives of the CEAP initiative include the quantitative evaluation of agricultural conservation practices through enhanced data collection and model development in selected watersheds. Once available online, this modified WEPP model will be a valuable tool for water resource managers to make scientifically informed decisions concerning the impact on and selection of conservation practices for improved stream water quality.

  16. Budgeting of major nutrients and the mitigation options for nutrient mining in semi-arid tropical agro-ecosystem of Tamil Nadu, India using NUTMON model.

    PubMed

    Surendran, U; Rama Subramoniam, S; Raja, P; Kumar, V; Murugappan, V

    2016-04-01

    Mining of nutrients from soil is a major problem in developing countries causing soil degradation and threaten long-term food production. The present study attempts to apply NUTrient MONitoring (NUTMON) model for carrying out nutrient budgeting to assess the stocks and flows of nitrogen (N), phosphorus (P), and potassium (K) in defined geographical unit based on the inputs, viz., mineral fertilizers, manures, atmospheric deposition, and sedimentation, and outputs, viz., harvested crop produces, residues, leaching, denitrification, and erosion losses. The study area covers Coimbatore and Erode Districts, which are potential agricultural areas in western agro-ecological zone of Tamil Nadu, India. The calculated nutrient balances for both the districts at district scale, using NUTMON methodology, were negative for nitrogen (N -3.3 and -10.1 kg ha(-1)) and potassium (K -58.6 and -9.8 kg ha(-1)) and positive for phosphorus (P +14.5 and 20.5 kg ha(-1)). Soil nutrient pool has to adjust the negative balance of N and K; there will be an expected mining of nutrient from the soil reserve. A strategy was attempted for deriving the fertilizer recommendation using Decision Support System for Integrated Fertilizer Recommendation (DSSIFER) to offset the mining in selected farms. The results showed that when DSSIFER recommended fertilizers are applied to crops, the nutrient balance was positive. NUTMON-Toolbox with DSSIFER would serve the purpose on enhancing soil fertility, productivity, and sustainability. The management options to mitigate nutrient mining with an integrated system approach are also discussed. PMID:27021693

  17. Budgeting of major nutrients and the mitigation options for nutrient mining in semi-arid tropical agro-ecosystem of Tamil Nadu, India using NUTMON model.

    PubMed

    Surendran, U; Rama Subramoniam, S; Raja, P; Kumar, V; Murugappan, V

    2016-04-01

    Mining of nutrients from soil is a major problem in developing countries causing soil degradation and threaten long-term food production. The present study attempts to apply NUTrient MONitoring (NUTMON) model for carrying out nutrient budgeting to assess the stocks and flows of nitrogen (N), phosphorus (P), and potassium (K) in defined geographical unit based on the inputs, viz., mineral fertilizers, manures, atmospheric deposition, and sedimentation, and outputs, viz., harvested crop produces, residues, leaching, denitrification, and erosion losses. The study area covers Coimbatore and Erode Districts, which are potential agricultural areas in western agro-ecological zone of Tamil Nadu, India. The calculated nutrient balances for both the districts at district scale, using NUTMON methodology, were negative for nitrogen (N -3.3 and -10.1 kg ha(-1)) and potassium (K -58.6 and -9.8 kg ha(-1)) and positive for phosphorus (P +14.5 and 20.5 kg ha(-1)). Soil nutrient pool has to adjust the negative balance of N and K; there will be an expected mining of nutrient from the soil reserve. A strategy was attempted for deriving the fertilizer recommendation using Decision Support System for Integrated Fertilizer Recommendation (DSSIFER) to offset the mining in selected farms. The results showed that when DSSIFER recommended fertilizers are applied to crops, the nutrient balance was positive. NUTMON-Toolbox with DSSIFER would serve the purpose on enhancing soil fertility, productivity, and sustainability. The management options to mitigate nutrient mining with an integrated system approach are also discussed.

  18. Improved Hypoxia Modeling for Nutrient Control Decisions in the Gulf of Mexico

    NASA Technical Reports Server (NTRS)

    Habib, Shahid; Pickering, Ken; Tzortziou, Maria; Maninio, Antonio; Policelli, Fritz; Stehr, Jeff

    2011-01-01

    The Gulf of Mexico Modeling Framework is a suite of coupled models linking the deposition and transport of sediment and nutrients to subsequent bio-geo chemical processes and the resulting effect on concentrations of dissolved oxygen in the coastal waters of Louisiana and Texas. Here, we examine the potential benefits of using multiple NASA remote sensing data products within this Modeling Framework for increasing the accuracy of the models and their utility for nutrient control decisions in the Gulf of Mexico. Our approach is divided into three components: evaluation and improvement of (a) the precipitation input data (b) atmospheric constituent concentrations in EPA's air quality/deposition model and (c) the calculation of algal biomass, organic carbon and suspended solids within the water quality/eutrophication models of the framework.

  19. Nutrient Dynamics In Flooded Wetlands. I: Model Development

    EPA Science Inventory

    Wetlands are rich ecosystems recognized for ameliorating floods, improving water quality and providing other ecosystem benefits. In this part of a two-paper sequel, we present a relatively detailed process-based model for nitrogen and phosphorus retention, cycling and removal in...

  20. Inferring time-variable effects of nutrient enrichment on marine ecosystems using inverse modelling and ecological network analysis.

    PubMed

    Luong, Anh D; De Laender, Frederik; Olsen, Yngvar; Vadstein, Olav; Dewulf, Jo; Janssen, Colin R

    2014-09-15

    We combined data from an outdoor mesocosm experiment with carbon budget modelling and an ecological network analysis to assess the effects of continuous nutrient additions on the structural and functional dynamics of a marine planktonic ecosystem. The food web receiving no nutrient additions was fuelled by detritus, as zooplankton consumed 7.2 times more detritus than they consumed algae. Nutrient supply instantly promoted herbivory so that it was comparable to detritivory at the highest nutrient addition rate. Nutrient-induced food web restructuring reduced carbon cycling and decreased the average number of compartments a unit flow of carbon crosses before dissipation. Also, the efficiency of copepod production, the link to higher trophic levels harvestable by man, was lowered up to 35 times by nutrient addition, but showed signs of recovery after 9 to 11 days. The dependency of the food web on exogenous input was not changed by the nutrient additions.

  1. Computer simulation of two chemostat models for one nutrient resource.

    PubMed

    Chichurin, Alexander V; Shvychkina, Helena N

    2016-08-01

    We consider Michaelis-Menten chemostat dynamic models, describing the process of continuous cultivation of bacteria with one organic substrate and two types of microorganisms in a case where the Michaelis-Menten constants for the two competing species of microorganisms are equal. For such a system we obtain solutions with the finite initial conditions assuming only positive values. As it is shown the problem is reduced to the solution of the nonlinear differential equation of the first order. For some parametric relations the solutions of the differential system are found in the analytical form. Using numerical procedures we construct software modules that allow modeling the chemostat cultivation for the changing parameters and visualizing the dynamics of the development process for each microorganism. A comparative analysis of some numerical methods that are used to integrate the resulting nonlinear differential equation is given. PMID:27211839

  2. Recovery of arctic tundra from thermal erosion disturbance is constrained by nutrient accumulation: a modeling analysis.

    PubMed

    Pearce, A R; Rastetter, E B; Kwiatkowski, B L; Bowden, W B; Mack, M C; Jiang, Y

    2015-07-01

    Abstract. We calibrated the Multiple Element Limitation (MEL) model to Alaskan arctic tundra to simulate recovery of thermal erosion features (TEFs) caused by permafrost thaw and mass wasting. TEFs could significantly alter regional carbon (C) and nutrient budgets because permafrost soils contain large stocks of soil organic matter (SOM) and TEFs are expected to become more frequent as the climate warms. We simulated recovery following TEF stabilization and did not address initial, short-term losses of C and nutrients during TEF formation. To capture the variability among and within TEFs, we modeled a range of post-stabilization conditions by varying the initial size of SOM stocks and nutrient supply rates. Simulations indicate that nitrogen (N) losses after the TEF stabilizes are small, but phosphorus (P) losses continue. Vegetation biomass recovered 90% of its undisturbed C, N, and P stocks in 100 years using nutrients mineralized from SOM. Because of low litter inputs but continued decomposition, younger SOM continued to be lost for 10 years after the TEF began to recover, but recovered to about 84% of its undisturbed amount in 100 years. The older recalcitrant SOM in mineral soil continued to be lost throughout the 100-year simulation. Simulations suggest that biomass recovery depended on the amount of SOM remaining after disturbance. Recovery was initially limited by the photosynthetic capacity of vegetation but became co-limited by N and P once a plant canopy developed. Biomass and SOM recovery was enhanced by increasing nutrient supplies, but the magnitude, source, and controls on these supplies are poorly understood. Faster mineralization of nutrients from SOM (e.g., by warming) enhanced vegetation recovery but delayed recovery of SOM. Taken together, these results suggest that although vegetation and surface SOM on TEFs recovered quickly (25 and 100 years, respectively), the recovery of deep, mineral soil SOM took centuries and represented a major

  3. A human PBPK/PD model to assess arsenic exposure risk through farmed tilapia consumption.

    PubMed

    Ling, M-P; Liao, C-M

    2009-07-01

    The purpose of this study was to develop a biologically based risk assessment model for human health through consumption of arsenic (As) contaminated farmed tilapia (Oreochromis mossambicus) from blackfoot disease (BFD)-endemic area in Taiwan for estimating the consumption advice. We linked a physiologically based pharmacokinetic (PBPK) and a pharmacodynamic (PD) model to account for the exposure and dose-response profiles of As in human. Risk analysis indicates that consumption of farmed tilapia poses no significant threat from As-induced lung and bladder cancers. The predicted risk-based median consumption advice was no more than 5-17 meals month(-1) (or 2-6 g day(-1)).

  4. Modeling Nutrient Loading to Watersheds in the Great Lakes Basin: A Detailed Source Model at the Regional Scale

    NASA Astrophysics Data System (ADS)

    Luscz, E.; Kendall, A. D.; Martin, S. L.; Hyndman, D. W.

    2011-12-01

    Watershed nutrient loading models are important tools used to address issues including eutrophication, harmful algal blooms, and decreases in aquatic species diversity. Such approaches have been developed to assess the level and source of nutrient loading across a wide range of scales, yet there is typically a tradeoff between the scale of the model and the level of detail regarding the individual sources of nutrients. To avoid this tradeoff, we developed a detailed source nutrient loading model for every watershed in Michigan's lower peninsula. Sources considered include atmospheric deposition, septic tanks, waste water treatment plants, combined sewer overflows, animal waste from confined animal feeding operations and pastured animals, as well as fertilizer from agricultural, residential, and commercial sources and industrial effluents . Each source is related to readily-available GIS inputs that may vary through time. This loading model was used to assess the importance of sources and landscape factors in nutrient loading rates to watersheds, and how these have changed in recent decades. The results showed the value of detailed source inputs, revealing regional trends while still providing insight to the existence of variability at smaller scales.

  5. Optimal Energy Consumption Model for Smart Grid Households With Energy Storage

    NASA Astrophysics Data System (ADS)

    Rajasekharan, Jayaprakash; Koivunen, Visa

    2014-12-01

    In this paper, we propose to model the energy consumption of smart grid households with energy storage systems as an intertemporal trading economy. Intertemporal trade refers to transaction of goods across time when an agent, at any time, is faced with the option of consuming or saving with the aim of using the savings in the future or spending the savings from the past. Smart homes define optimal consumption as either balancing/leveling consumption such that the utility company is presented with a uniform demand or as minimizing consumption costs by storing energy during off-peak time periods when prices are lower and use the stored energy during peak time periods when prices are higher. Due to the varying nature of energy requirements of household and market energy prices over different time periods in a day, households face a trade-off between consuming to meet their current energy requirements and/or storing energy for future consumption and/or spending energy stored in the past. These trade-offs or consumption preferences of the household are modeled as utility functions using consumer theory. We introduce two different utility functions, one for cost minimization and another for consumption balancing/leveling, that are maximized subject to respective budget, consumption, storage and savings constraints to solve for the optimum consumption profile. The optimization problem of a household with energy storage is formulated as a geometric program for consumption balancing/leveling, while cost minimization is formulated as a linear programming problem. Simulation results show that the proposed model achieves extremely low peak to average ratio in the consumption balancing/leveling scheme with about 8% reduction in consumption costs and the least possible amount for electricity bill with about 12% reduction in consumption costs in the cost minimization scheme.

  6. Springs as Model Systems for Aquatic Ecosystems Ecology: Stoichiometry, Metabolism and Nutrient Limitation

    NASA Astrophysics Data System (ADS)

    Cohen, M. J.; Nifong, R. L.; Kurz, M. J.; Martin, J. B.; Cropper, W. P.; Korhnak, L. V.

    2013-12-01

    and P gradients, they are more plastic in response to micronutrient variation, particularly for iron and manganese. Expanding on the Droop model framework for understanding nutrient assimilation and plant growth, we discuss these results in the context of nutrient limitation of benthic-dominated lotic systems. We conclude that these spring-fed model systems are N and P saturated, and discuss tools for predicting nutrient limitation and thus eutrophication in flowing waters.

  7. Modeling Tribal Exposures to PCBs from Fish Consumption

    EPA Science Inventory

    Studies have shown that U.S. population continues to be exposed to polychlorinated biphenyls (PCBs), despite the ban ~40 years ago. Fish intake is a major pathway, especially, for high fish-consumption groups. Exposure assessment and risk management considerations for tribal fish...

  8. Modeling tribal exposures to methyl mercury from fish consumption

    EPA Science Inventory

    Exposure assessment and risk management considerations for tribal fish consumption are different than for the general U.S. population because of higher fish intake from subsistence fishing and/or from unique cultural practices. This research summarizes analyses of available data ...

  9. Modeling the fluid-dynamics and oxygen consumption in a porous scaffold stimulated by cyclic squeeze pressure.

    PubMed

    Ferroni, Marco; Giusti, Serena; Nascimento, Diana; Silva, Ana; Boschetti, Federica; Ahluwalia, Arti

    2016-08-01

    The architecture and dynamic physical environment of tissues can be recreated in-vitro by combining 3D porous scaffolds and bioreactors able to apply controlled mechanical stimuli on cells. In such systems, the entity of the stimuli and the distribution of nutrients within the engineered construct depend on the micro-structure of the scaffolds. In this work, we present a new approach for optimizing computational fluid-dynamics (CFD) models for the investigation of fluid-induced forces generated by cyclic squeeze pressure within a porous construct, coupled with oxygen consumption of cardiomyocytes. A 2D axial symmetric macro-scaled model of a squeeze pressure bioreactor chamber was used as starting point for generating time dependent pressure profiles. Subsequently the fluid movement generated by the pressure fields was coupled with a complete 3D micro-scaled model of a porous protein cryogel. Oxygen transport and consumption inside the scaffold was evaluated considering a homogeneous distribution of cardiomyocytes throughout the structure, as confirmed by preliminary cell culture experiments. The results show that a 3D description of the system, coupling a porous geometry and time dependent pressure driven flow with fluid-structure-interaction provides an accurate and meaningful description of the microenvironment in terms of shear stress and oxygen distribution than simple stationary 2D models.

  10. Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants.

    PubMed

    Barat, R; Serralta, J; Ruano, M V; Jiménez, E; Ribes, J; Seco, A; Ferrer, J

    2013-01-01

    This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nitrogen removal via nitrite and the formation of the solids most likely to precipitate in anaerobic digesters. The solids considered in BNRM2 are: struvite, amorphous calcium phosphate, hidroxyapatite, newberite, vivianite, strengite, variscite, and calcium carbonate. With regard to nitrogen removal via nitrite, apart from nitrite oxidizing bacteria two groups of ammonium oxidizing organisms (AOO) have been considered since different sets of kinetic parameters have been reported for the AOO present in activated sludge systems and SHARON (Single reactor system for High activity Ammonium Removal Over Nitrite) reactors. Due to the new processes considered, BNRM2 allows an accurate prediction of wastewater treatment plant performance in wider environmental and operating conditions. PMID:23552235

  11. Short-Term Energy Outlook Model Documentation: Natural Gas Consumption and Prices

    EIA Publications

    2015-01-01

    The natural gas consumption and price modules of the Short-Term Energy Outlook (STEO) model are designed to provide consumption and end-use retail price forecasts for the residential, commercial, and industrial sectors in the nine Census districts and natural gas working inventories in three regions. Natural gas consumption shares and prices in each Census district are used to calculate an average U.S. retail price for each end-use sector.

  12. Energy and nutrient deposition and excretion in the reproducing sow: model development and evaluation.

    PubMed

    Hansen, A V; Strathe, A B; Theil, P K; Kebreab, E

    2014-06-01

    Air and nutrient emissions from swine operations raise environmental concerns. During the reproduction phase, sows consume and excrete large quantities of nutrients. The objective of this study was to develop a mathematical model to describe energy and nutrient partitioning and predict manure excretion and composition and methane emissions on a daily basis. The model was structured to contain gestation and lactation modules, which can be run separately or sequentially, with outputs from the gestation module used as inputs to the lactation module. In the gestating module, energy and protein requirements for maintenance, and fetal and maternal growth were described. In the lactating module, a factorial approach was used to estimate requirements for maintenance, milk production, and maternal growth. The priority for nutrient partitioning was assumed to be in the order of maintenance, milk production, and maternal growth with body tissue losses constrained within biological limits. Global sensitivity analysis showed that nonlinearity in the parameters was small. The model outputs considered were the total protein and fat deposition, average urinary and fecal N excretion, average methane emission, manure carbon excretion, and manure production. The model was evaluated using independent data sets from the literature using root mean square prediction error (RMSPE) and concordance correlation coefficients. The gestation module predicted body fat gain better than body protein gain, which was related to predictions of body fat and protein loss from the lactation model. Nitrogen intake, urine N, fecal N, and milk N were predicted with RMSPE as percentage of observed mean of 9.7, 17.9, 10.0, and 7.7%, respectively. The model provided a framework, but more refinements and improvements in accuracy of prediction (particularly urine N) are required before the model can be used to assess environmental mitigation options from sow operations.

  13. A model for gas and nutrient exchange in the chorionic vasculature system of the mouse placenta

    NASA Astrophysics Data System (ADS)

    Mirbod, Parisa; Sled, John

    2015-11-01

    The aim of this study is to develop an analytical model for the oxygen and nutrient transport from the umbilical cord to the small villous capillaries. The nutrient and carbon dioxide removal from the fetal cotyledons in the mouse placental system has also been considered. This model describes the mass transfer between the fetal and the maternal red blood cells in the chorionic arterial vasculature system. The model reveals the detail fetal vasculature system and its geometry and the precise mechanisms of mass transfer through the placenta. The dimensions of the villous capillaries, the total length of the villous trees, the total villi surface area, and the total resistance to mass transport in the fetal villous trees has also been defined. This is the first effort to explain the reason why there are at least 7 lobules in the mouse placenta from the fluid dynamics point of view.

  14. The Catchment Runoff Attenuation Flux Tool, a minimum information requirement nutrient pollution model

    NASA Astrophysics Data System (ADS)

    Adams, R.; Quinn, P. F.; Bowes, M. J.

    2015-04-01

    A model for simulating runoff pathways and water quality fluxes has been developed using the minimum information requirement (MIR) approach. The model, the Catchment Runoff Attenuation Flux Tool (CRAFT), is applicable to mesoscale catchments and focusses primarily on hydrological pathways that mobilise nutrients. Hence CRAFT can be used to investigate the impact of flow pathway management intervention strategies designed to reduce the loads of nutrients into receiving watercourses. The model can help policy makers meet water quality targets and consider methods to obtain "good" ecological status. A case study of the 414 km2 Frome catchment, Dorset, UK, has been described here as an application of CRAFT in order to highlight the above issues at the mesoscale. The model was primarily calibrated on 10-year records of weekly data to reproduce the observed flows and nutrient (nitrate nitrogen - N; phosphorus - P) concentrations. Data from 2 years with sub-daily monitoring at the same site were also analysed. These data highlighted some additional signals in the nutrient flux, particularly of soluble reactive phosphorus, which were not observable in the weekly data. This analysis has prompted the choice of using a daily time step as the minimum information requirement to simulate the processes observed at the mesoscale, including the impact of uncertainty. A management intervention scenario was also run to demonstrate how the model can support catchment managers investigating how reducing the concentrations of N and P in the various flow pathways. This mesoscale modelling tool can help policy makers consider a range of strategies to meet the European Union (EU) water quality targets for this type of catchment.

  15. Modeling the Transport and Fate of Fecal Pollution and Nutrients of Miyun Reservoir

    NASA Astrophysics Data System (ADS)

    Liu, L.; Fu, X.; Wang, G.

    2009-12-01

    Miyun Reservoir, a mountain valley reservoir, is located 100 km northeast of Beijing City. Besides the functions of flood control, irrigation and fishery for Beijing area, Miyun Reservoir is the main drinking water storage for Beijing city. The water quality is therefore of great importance. Recently, the concentration of fecal pollution and nutrients in the reservoir are constantly rising to arrest the attention of Beijing municipality. Fecal pollution from sewage is a significant public health concern due to the known presence of human viruses and parasites in these discharges. To investigate the transport and fate of the fecal pollution and nutrients at Miyun reservoir and the health risks associated with drinking and fishery, the reservoir and two tributaries, Chaohe river and Baihe river discharging into it are being examined for bacterial, nutrients and other routine pollution. To understand the relative importance of different processes influencing pollution transport and inactivation, a finite-element model of surf-zone hydrodynamics (coupled with models for temperature, fecal pollution, nutrients and other routine contaminants) is used. The developed models are being verified by the observed water quality data including water temperature, conductivities and dissolved oxygen from the reservoir and its tributaries. Different factors impacting the inactivation of fecal pollution and the transport of nutrients such as water temperature, sedimentation, sunlight insolation are evaluated for Miyun reservoir by a sensitivity analysis analogized from the previous research of Lake Michigan (figure 1, indicating that solar insolation dominates the inactivation of E. Coli, an indicator of fecal pollution, Liu et al. 2006). The calibrated modeling system can be used to temporally and spatially simulate and predict the variation of the concentration of fecal pollution and nutrients of Miyun reservoir. Therefore this research can provide a forecasting tool for the

  16. Modeling the Relative Importance of Nutrient and Carbon Loads, Boundary Fluxes, and Sediment Fluxes on Gulf of Mexico Hypoxia.

    PubMed

    Feist, Timothy J; Pauer, James J; Melendez, Wilson; Lehrter, John C; DePetro, Phillip A; Rygwelski, Kenneth R; Ko, Dong S; Kreis, Russell G

    2016-08-16

    The Louisiana continental shelf in the northern Gulf of Mexico experiences bottom water hypoxia in the summer. In this study, we applied a biogeochemical model that simulates dissolved oxygen concentrations on the shelf in response to varying riverine nutrient and organic carbon loads, boundary fluxes, and sediment fluxes. Five-year model simulations demonstrated that midsummer hypoxic areas were most sensitive to riverine nutrient loads and sediment oxygen demand from settled organic carbon. Hypoxic area predictions were also sensitive to nutrient and organic carbon fluxes from lateral boundaries. The predicted hypoxic area decreased with decreases in nutrient loads, but the extent of change was influenced by the method used to estimate model boundary concentrations. We demonstrated that modeling efforts to predict changes in hypoxic area on the continental shelf in relationship to changes in nutrients should include representative boundary nutrient and organic carbon concentrations and functions for estimating sediment oxygen demand that are linked to settled organic carbon derived from water-column primary production. On the basis of our model analyses using the most representative boundary concentrations, nutrient loads would need to be reduced by 69% to achieve the Gulf of Mexico Nutrient Task Force Action Plan target hypoxic area of 5000 km(2). PMID:27406634

  17. Modeling the Relative Importance of Nutrient and Carbon Loads, Boundary Fluxes, and Sediment Fluxes on Gulf of Mexico Hypoxia.

    PubMed

    Feist, Timothy J; Pauer, James J; Melendez, Wilson; Lehrter, John C; DePetro, Phillip A; Rygwelski, Kenneth R; Ko, Dong S; Kreis, Russell G

    2016-08-16

    The Louisiana continental shelf in the northern Gulf of Mexico experiences bottom water hypoxia in the summer. In this study, we applied a biogeochemical model that simulates dissolved oxygen concentrations on the shelf in response to varying riverine nutrient and organic carbon loads, boundary fluxes, and sediment fluxes. Five-year model simulations demonstrated that midsummer hypoxic areas were most sensitive to riverine nutrient loads and sediment oxygen demand from settled organic carbon. Hypoxic area predictions were also sensitive to nutrient and organic carbon fluxes from lateral boundaries. The predicted hypoxic area decreased with decreases in nutrient loads, but the extent of change was influenced by the method used to estimate model boundary concentrations. We demonstrated that modeling efforts to predict changes in hypoxic area on the continental shelf in relationship to changes in nutrients should include representative boundary nutrient and organic carbon concentrations and functions for estimating sediment oxygen demand that are linked to settled organic carbon derived from water-column primary production. On the basis of our model analyses using the most representative boundary concentrations, nutrient loads would need to be reduced by 69% to achieve the Gulf of Mexico Nutrient Task Force Action Plan target hypoxic area of 5000 km(2).

  18. Computer model of hydroponics nutrient solution pH control using ammonium.

    PubMed

    Pitts, M; Stutte, G

    1999-01-01

    A computer simulation of a hydroponics-based plant growth chamber using ammonium to control pH was constructed to determine the feasibility of such a system. In nitrate-based recirculating hydroponics systems, the pH will increase as plants release hydroxide ions into the nutrient solution to maintain plant charge balance. Ammonium is an attractive alternative to traditional pH controls in an ALSS, but requires careful monitoring and control to avoid overdosing the plants with ammonium. The primary advantage of using NH4+ for pH control is that it exploits the existing plant nutrient uptake charge balance mechanisms to maintain solution pH. The simulation models growth, nitrogen uptake, and pH of a l-m2 stand of wheat. Simulation results indicated that ammonium-based control of nutrient solution pH is feasible using a proportional integral controller. Use of a 1 mmol/L buffer (Ka = 1.6 x 10(-6)) in the nutrient solution is required.

  19. Relationship between fire temperature and changes in chemical soil properties: a conceptual model of nutrient release

    NASA Astrophysics Data System (ADS)

    Thomaz, Edivaldo L.; Doerr, Stefan H.

    2014-05-01

    The purpose of this study was to evaluate the effects of fire temperatures (i.e., soil heating) on nutrient release and aggregate physical changes in soil. A preliminary conceptual model of nutrient release was established based on results obtained from a controlled burn in a slash-and-burn agricultural system located in Brazil. The study was carried out in clayey subtropical soil (humic Cambisol) from a plot that had been fallow for 8 years. A set of three thermocouples were placed in four trenches at the following depths: 0 cm on the top of the mineral horizon, 1.0 cm within the mineral horizon, and 2 cm within the mineral horizon. Three soil samples (true independent sample) were collected approximately 12 hours post-fire at depths of 0-2.5 cm. Soil chemical changes were more sensitive to fire temperatures than aggregate physical soil characteristics. Most of the nutrient response to soil heating was not linear. The results demonstrated that moderate temperatures (< 400°C) had a major effect on nutrient release (i.e., the optimum effect), whereas high temperatures (> 500 °C) decreased soil fertility.

  20. Modeling, research and development of the system for optimal heat consumption of a building

    NASA Astrophysics Data System (ADS)

    Kovalnogov, Vladislav N.; Chamchiyan, Yuri E.; Suranov, Dmitry V.

    2016-06-01

    The work sets out the technical, software and organizational and methodological solutions for automated management and optimization of a building's heat consumption. It shows the results of modeling and research on the effectiveness of the automated system of heat consumption control of the main building of Ulyanovsk State Technical University.

  1. Social Modeling Influences and Alcohol Consumption during the First Semester of College: A Natural History Study

    ERIC Educational Resources Information Center

    Talbott, Laura L.; Moore, Charity G.; Usdan, Stuart L.

    2012-01-01

    The authors examine both the alcohol consumption pattern of freshmen students during their first semester and the degree to which social modeling of peer behavior impacts consumption. A total of 534 students, residing on campus, were prospectively examined at four 30-day intervals. Data were evaluated on the basis of age, gender, and the effects…

  2. Modeling Size-Selective Soil Erosion and Nutrient Transport in Flume-Scale Experiments

    NASA Astrophysics Data System (ADS)

    Heng, B. P.; Sander, G. C.; Armstrong, A.; Chandler, J. H.; Quinton, J. N.; Scott, C. F.; Wheatley, A. D.

    2009-12-01

    The erosion of agricultural soils can have severe consequences for surface water quality as well as agricultural productivity. Where surface runoff occurs, it can carry sediment and nutrients quickly and in large quantities into water bodies. It is therefore important to be able to predict with some confidence their movement in overland flow. Since particulate pollutants (such as phosphorus) bind preferentially to the finer soil particles, we need to know the particle size distribution (PSD) of the sediment being transported as well as the bulk quantity. In this paper, we use a size-selective soil erosion model (coupled with the Saint-Venant equations for overland flow) to reproduce flume-scale experimental observations of sediment and nutrient transport dynamics under simulated rainfall. In view of the differences between experimental replicates, we model the experimental runs individually with separate sets of parameters. The model results are promising in relation to the PSD as well as the concentration of sediment in the surface runoff. We show that soil erosion and sediment transport can be significantly affected by seemingly minor topographical differences (measured by close range photogrammetry). We also analyze the optimized parameters for trends that give further insight into erosion processes. Finally, we present a single-parameter nutrient transport model that can reproduce with reasonable accuracy the dynamics of phosphorus export.

  3. Daily consumption of foods and nutrients from institutional and home sources among young children attending two contrasting day-care centers in Guatemala City.

    PubMed

    Vossenaar, M; Jaramillo, P M; Soto-Méndez, M-J; Panday, B; Hamelinck, V; Bermúdez, O I; Doak, C M; Mathias, P; Solomons, N W

    2012-12-01

    Adequate nutrition is critical to child development and institutions such as day-care centers could potentially complement children's diets to achieve optimal daily intakes. The aim of the study was to describe the full-day diet of children, examining and contrasting the relative contribution of home-derived versus institutional energy and nutrient sources. The present comparison should be considered in the domain of a case-study format. The diets of 33, 3-6 y old children attending low-income day-care centers serving either 3 or a single meal were examined. The home-diet was assessed by means of 3 non-consecutive 24-hr recalls. Estimated energy and nutrient intakes at the centers and at home were assessed and related to Recommended Nutrient Intakes (RNI). Nutrient densities, critical densities and main sources of nutrients were computed. We observed that in children attending the day-care center serving three meals, home-foods contributed less than half the daily energy (47.7%) and between 29.9% and 53.5% of daily nutrients. In children receiving only lunch outside the home, energy contribution from the home was 83.9% and 304 kcal lower than for children receiving 3 meals. Furthermore, between 59.0% and 94.8% of daily nutrients were provided at home. Daily energy, nutrient intakes and nutrient densities were well above the nutrient requirements for this age group, and particularly high for vitamin A. The overall dietary variety was superior in the situation of greater contribution of home fare, but overall the nutrient density and adequacy of the aggregate intakes did not differ in any important manner. PMID:24020251

  4. Nutrient (N, P, Si) transfers in the subtropical Red River system (China and Vietnam): Modelling and budget of nutrient sources and sinks

    NASA Astrophysics Data System (ADS)

    Le, Thi Phuong Quynh; Gilles, Billen; Garnier, Josette; Sylvain, Théry; Denis, Ruelland; Anh, Nghiem Xuan; Minh, Chau Van

    2010-02-01

    The Red River system, which has a population density that varies from 80 to over 1000 inhabitants km -2 in the different sectors of its watershed, is a typical example of a subtropical system experiencing high human pressure. A monthly survey of nutrient concentration was conducted at the outlet of the three main tributaries (Da, Thao and Lo) and at Hanoi on the main branch of the Red River in the upper part of the delta. Samples from headwater streams or irrigation channels draining homogeneous land use classes also were analysed. A GIS database describing the characteristics of the watershed in terms of morphology, climate, land use and population has been established. This served as the basis for implementing the Seneque/Riverstrahler model, which allowed calculation of nutrient transfers and transformations along the whole drainage network of the Red River system. The model was validated using the measured nutrient concentrations obtained during the survey and was used to establish an overall description and a comprehensive budget of nutrient transfer, retention and delivery for the three main sub-basins and the upper part of the delta upstream from Hanoi.

  5. A mechanistic soil biogeochemistry model with explicit representation of microbial and macrofaunal activities and nutrient cycles

    NASA Astrophysics Data System (ADS)

    Fatichi, Simone; Manzoni, Stefano; Or, Dani; Paschalis, Athanasios

    2016-04-01

    The potential of a given ecosystem to store and release carbon is inherently linked to soil biogeochemical processes. These processes are deeply connected to the water, energy, and vegetation dynamics above and belowground. Recently, it has been advocated that a mechanistic representation of soil biogeochemistry require: (i) partitioning of soil organic carbon (SOC) pools according to their functional role; (ii) an explicit representation of microbial dynamics; (iii) coupling of carbon and nutrient cycles. While some of these components have been introduced in specialized models, they have been rarely implemented in terrestrial biosphere models and tested in real cases. In this study, we combine a new soil biogeochemistry model with an existing model of land-surface hydrology and vegetation dynamics (T&C). Specifically the soil biogeochemistry component explicitly separates different litter pools and distinguishes SOC in particulate, dissolved and mineral associated fractions. Extracellular enzymes and microbial pools are explicitly represented differentiating the functional roles of bacteria, saprotrophic and mycorrhizal fungi. Microbial activity depends on temperature, soil moisture and litter or SOC stoichiometry. The activity of macrofauna is also modeled. Nutrient dynamics include the cycles of nitrogen, phosphorous and potassium. The model accounts for feedbacks between nutrient limitations and plant growth as well as for plant stoichiometric flexibility. In turn, litter input is a function of the simulated vegetation dynamics. Root exudation and export to mycorrhiza are computed based on a nutrient uptake cost function. The combined model is tested to reproduce respiration dynamics and nitrogen cycle in few sites where data were available to test plausibility of results across a range of different metrics. For instance in a Swiss grassland ecosystem, fine root, bacteria, fungal and macrofaunal respiration account for 40%, 23%, 33% and 4% of total belowground

  6. A dynamic CSTT model for the effects of added nutrients in Loch Creran, a shallow fjord

    NASA Astrophysics Data System (ADS)

    Laurent, Céline; Tett, Paul; Fernandes, Teresa; Gilpin, Linda; Jones, Ken

    2006-07-01

    Despite a tendency for the complexity of physical-biological models to increase, simple coupled models remain useful for some applications and can provide insights into crucial links between physical and biological processes. This argument is illustrated with an account of a simple 3-box model intended to help assess the capacity of fjords to assimilate nutrients from fish farms. The model, a dynamic version of the UK "Comprehensive Studies Task Team" (CSTT) steady-state model for eutrophication, was applied to Loch Creran (Scottish Western Highlands) and was implemented using Stella 8 and tested using historical data from 1975 (before the installation of a salmon farm) and field data collected in 2003, during the period of operation of the farm. The model's biological state variables are chlorophyll, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), and it includes a simple run-off model to convert rainfall into river discharge. The physical processes involved in exchange between the loch and the adjacent waters of the Firth of Lorne were parameterised as a constant daily exchange rate. Between 1975 and 2003, local inputs of nutrient increased but, despite this, there was little apparent increase in nutrient concentrations in the loch, and observed chlorophyll concentrations decreased substantially. Model simulations of chlorophyll and DIN agreed well with observations in 1975, as did DIN simulations in 2003. However, simulated chlorophyll was overestimated in 2003. Some of the agreement between observations and simulations come from the use of observed boundary conditions to force the model. However, even when boundary conditions are subtracted from simulations and observations, the simulations in most cases retain a significant correlation with observations, demonstrating that the model's 'interior' processes do add to its ability to replicate conditions in the loch.

  7. Greenland Ice Sheet nutrient export: Towards a reaction-transport model of fjord dynamics

    NASA Astrophysics Data System (ADS)

    Crosby, James; Arndt, Sandra; Wadham, Jemma; Bingham, Rory

    2015-04-01

    Glacial runoff has the potential to deliver large quantities of dissolved and particulate bioavailable nutrients to surrounding marine environments. The marine waters bordering the Greenland Ice Sheet (GrIS) host some of the most productive ecosystems in the world, and possess high socio-economic value from fisheries. Furthermore, the productivity of phytoplankton in the North Atlantic sequesters CO2 from the atmosphere with a potentially important effect on the global coastal ocean CO2 budget. Providing a link between glacier and coastal ocean, fjords are critical components of the marine coastal system in this region, acting as both transfer routes and sinks for glacial nutrient export. As such they have the potential to act as significant biogeochemical processors, yet are currently underexplored. We propose to close this knowledge gap by developing a coupled 2D physical-biogeochemical model of the Godthåbsfjord system to quantitatively assess the impact of nutrients exported from the GrIS on fjord primary productivity and biogeochemical dynamics. Here, we present the first results of the hydrodynamic model. Hydrodynamic circulation patterns and freshwater transit times are explored to provide a first understanding of the glacier-fjord-ocean continuum. The hydrodynamic model will be dynamically coupled to a biogeochemical model with the view to providing a comprehensive understanding of the fate of nutrients exported from the GrIS. This will be extended to address the future sensitivity of these coastal systems to a warming climate, knowledge of which is critical when assessing the role of these dynamic and unique environments.

  8. Nutrient biogeochemical cycles in the Gulf of Riga: scaling up field studies with a mathematical model

    NASA Astrophysics Data System (ADS)

    Savchuk, Oleg P.

    2002-05-01

    A box model has been implemented to understand the large-scale biogeochemical cycles of nitrogen, phosphorus, and silicon in the Gulf of Riga. The large data sets collected within the international Gulf of Riga Project in 1993/1995 were used to validate the model. The comparison to data was useful in scaling up to the gulf-wide level and scrutinizing the conclusions based on short-term field surveys and experimental studies. The simulations indicate that the limiting role was passing from silicon to phosphorus to nitrogen over the seasons of organic production. However, on an annual scale, nutrient limitation was close to the "Redfield equilibrium". Mass balance considerations, based on modeled coupled fluxes, disagree with the conclusions on low sediment denitrification and high phosphorus retention in the pelagic system, which were derived from isolated measurements. Nutrient budgets constructed with the model revealed the high buffer capacity of the Gulf of Riga. The nutrient residence times span a range from 6 years for N to 70 years for Si. The buffering arises from intensive internal recycling in the water body and by the bottom sediments. The budgets indicate that the Gulf retains about two-thirds of external nitrogen and silicon inputs, while phosphorus retention is only 10%. A slow response to external perturbations is demonstrated with numerical experiments run for 15 years under 50% reductions of terrestrial nutrient inputs. These experiments imply that the most effective is the N+P reduction scenario, which resulted in a 20% decrease of primary production after 12 years. A reduction of P resulted in only a 6% decrease of primary production; however, it yielded an 80% drop in the amount of nitrogen fixation.

  9. Nonlinear regression modeling of nutrient loads in streams: A Bayesian approach

    USGS Publications Warehouse

    Qian, S.S.; Reckhow, K.H.; Zhai, J.; McMahon, G.

    2005-01-01

    A Bayesian nonlinear regression modeling method is introduced and compared with the least squares method for modeling nutrient loads in stream networks. The objective of the study is to better model spatial correlation in river basin hydrology and land use for improving the model as a forecasting tool. The Bayesian modeling approach is introduced in three steps, each with a more complicated model and data error structure. The approach is illustrated using a data set from three large river basins in eastern North Carolina. Results indicate that the Bayesian model better accounts for model and data uncertainties than does the conventional least squares approach. Applications of the Bayesian models for ambient water quality standards compliance and TMDL assessment are discussed. Copyright 2005 by the American Geophysical Union.

  10. Modelling of Scenedesmus obliquus; function of nutrients with modified Gompertz model.

    PubMed

    Celekli, Abuzer; Balci, Muharrem; Bozkurt, Hüseyin

    2008-12-01

    This study attempted to investigate variation in biovolume of Scenedesmus obliquus, in the modified Johnson medium at 20+/-2 degrees C, under 16kergcm(-2)s(-1) continuous illumination. The experiments were carried out at four nitrate (8, 12, 16, and 20mM) and four phosphate (0.1, 0.3, 0.5 and 0.7mM) concentrations at pH 7 and 8. The best response for algal growth was found at 0.3mM phosphate and 12mM nitrate at pH 7, as it was obtained from weight averaging method. Besides, optimum phosphate and nitrate concentrations significantly distinguished (p<0.01) from other concentrations according to Turkey's HSD test. Key features of the growth of S. obliquus under phosphate and nitrate influenced batch culture was successfully predicted by modified Gompertz model. Through the cultivations, specific growth rate (mu) ranged from 0.30 to 1.02 day(-1), while biovolume doubling time (td) varied from 0.68 to 2.30 days. There were important differences (p<0.05) for both mu and td among response variables. Both nutrients displayed noteworthy effect (p<0.01) on the algal biovolume. PMID:18501595

  11. Modelling of Scenedesmus obliquus; function of nutrients with modified Gompertz model.

    PubMed

    Celekli, Abuzer; Balci, Muharrem; Bozkurt, Hüseyin

    2008-12-01

    This study attempted to investigate variation in biovolume of Scenedesmus obliquus, in the modified Johnson medium at 20+/-2 degrees C, under 16kergcm(-2)s(-1) continuous illumination. The experiments were carried out at four nitrate (8, 12, 16, and 20mM) and four phosphate (0.1, 0.3, 0.5 and 0.7mM) concentrations at pH 7 and 8. The best response for algal growth was found at 0.3mM phosphate and 12mM nitrate at pH 7, as it was obtained from weight averaging method. Besides, optimum phosphate and nitrate concentrations significantly distinguished (p<0.01) from other concentrations according to Turkey's HSD test. Key features of the growth of S. obliquus under phosphate and nitrate influenced batch culture was successfully predicted by modified Gompertz model. Through the cultivations, specific growth rate (mu) ranged from 0.30 to 1.02 day(-1), while biovolume doubling time (td) varied from 0.68 to 2.30 days. There were important differences (p<0.05) for both mu and td among response variables. Both nutrients displayed noteworthy effect (p<0.01) on the algal biovolume.

  12. Distance-decay patterns of nutrient loading at watershed scale: Regression modeling with a special spatial aggregation strategy

    NASA Astrophysics Data System (ADS)

    Zhang, Tao

    2011-05-01

    SummaryThe effect of distance-decay on nutrient flux usually plays an important role in nutrient retention from non-point sources to surface waters. However, the distance-decay effect has been inappropriately neglected in many studies that adopted regression modeling method to quantify the relationship between watershed landscape and in-stream nutrient loading level. The goal of this study was to develop non-linear regression models that better quantify the role of distance on non-point source nutrient loads in rivers by using simulation results of a spatially-explicit model applied to the watersheds in the Upper Chattahoochee River Basin, Georgia. Because a detailed spatially-explicit modeling approach typically simulates the nutrient flux across the entire watershed, it provides opportunities to examine the nutrient decay patterns at watershed scale. The simulation results confirmed that regarding the effect of flow distance on nutrient loading, the exponential decay setting in the spatially-explicit model performs well. Other heterogeneous factors including slope and soil conditions do affect the decay results but not strongly enough to change the general exponential patterns. The nutrient contribution from areas that were greater than 300 meters to the river network was negligible. It was also found that the decay rate for urban lands is lower than that for other land-covers. Based on these findings, a spatial aggregation strategy in the lateral dimension of the river network was adopted and eight non-linear regression models which explicitly addressed the effects of distance-decay were designed to estimate the nutrient annual average loads. The model validation results showed that three of them can well estimate the nutrient loads. This study shows the usage of stream-lateral-dimension aggregation strategy in addressing nutrient distance-decay patterns and developing simple regression models of nutrient loading. This study also illustrates the advantages of

  13. Study on Soil Nutrient Management Andfertilization Model in Ningxia County Territorywith Gis

    NASA Astrophysics Data System (ADS)

    Liu, Libo; Zhou, Guomin

    By adopting the GIS technology, this thesis tries to collect and recognize the existing pedological map, the soil nutrient graphic document and other related documents data of Ningxia. And with the classification and filtration to the material, the spatial databases and the attribute database can be established to combine the county territory soil nutrient data and the geography graph together to make the uninteresting form data visualized. Based on the soil nutrient database, the mathematical model is established by means of the design of the regression orthogonal combination. And Through the mathematical model optimization, the quantity of nitrophoskas which is employed at the maximum production rate as well as at the lowest can be obtained. With these, the paper proposes a model which can dispose, judge and analyze all the factors related to the fertilization to achieve the concrete formula and the amount of commonly used fat and the special-purpose compound fat. Therefore, the data analysis and the auxiliary decision-makingenormously facilitate, and the automatization and the rationalization of all kind of crop's fertilization scheme in Ningxia can be realized.

  14. Stable isotopes and Digital Elevation Models to study nutrient inputs in high-Arctic lakes

    NASA Astrophysics Data System (ADS)

    Calizza, Edoardo; Rossi, David; Costantini, Maria Letizia; Careddu, Giulio; Rossi, Loreto

    2016-04-01

    Ice cover, run-off from the watershed, aquatic and terrestrial primary productivity, guano deposition from birds are key factors controlling nutrient and organic matter inputs in high-Arctic lakes. All these factors are expected to be significantly affected by climate change. Quantifying these controls is a key baseline step to understand what combination of factors subtends the biological productivity in Arctic lakes and will drive their ecological response to environmental change. Basing on Digital Elevation Models, drainage maps, and C and N elemental content and stable isotope analysis in sediments, aquatic vegetation and a dominant macroinvertebrate species (Lepidurus arcticus Pallas 1973) belonging to Tvillingvatnet, Storvatnet and Kolhamna, three lakes located in North Spitsbergen (Svalbard), we propose an integrated approach for the analysis of (i) nutrient and organic matter inputs in lakes; (ii) the role of catchment hydro-geomorphology in determining inter-lake differences in the isotopic composition of sediments; (iii) effects of diverse nutrient inputs on the isotopic niche of Lepidurus arcticus. Given its high run-off and large catchment, organic deposits in Tvillingvatnet where dominated by terrestrial inputs, whereas inputs were mainly of aquatic origin in Storvatnet, a lowland lake with low potential run-off. In Kolhamna, organic deposits seem to be dominated by inputs from birds, which actually colonise the area. Isotopic signatures were similar between samples within each lake, representing precise tracers for studies on the effect of climate change on biogeochemical cycles in lakes. The isotopic niche of L. aricticus reflected differences in sediments between lakes, suggesting a bottom-up effect of hydro-geomorphology characterizing each lake on nutrients assimilated by this species. The presented approach proven to be an effective research pathway for the identification of factors subtending to nutrient and organic matter inputs and transfer

  15. Layered Plant-Growth Media for Optimizing Gaseous, Liquid and Nutrient Requirements: Modeling, Design and Monitoring

    NASA Astrophysics Data System (ADS)

    Heinse, R.; Jones, S. B.; Bingham, G.; Bugbee, B.

    2006-12-01

    Rigorous management of restricted root zones utilizing coarse-textured porous media greatly benefits from optimizing the gas-water balance within plant-growth media. Geophysical techniques can help to quantify root- zone parameters like water content, air-filled porosity, temperature and nutrient concentration to better address the root systems performance. The efficiency of plant growth amid high root densities and limited volumes is critically linked to maintaining a favorable water content/air-filled porosity balance while considering adequate fluxes to replenish water at decreasing hydraulic conductivities during uptake. Volumes adjacent to roots also need to be optimized to provide adequate nutrients throughout the plant's life cycle while avoiding excessive salt concentrations. Our objectives were to (1) design and model an optimized root zone system using optimized porous media layers, (2) verify our design by monitoring the water content distribution and tracking nutrient release and transport, and (3) mimic water and nutrient uptake using plants or wicks to draw water from the root system. We developed a unique root-zone system using layered Ottawa sands promoting vertically uniform water contents and air-filled porosities. Watering was achieved by maintaining a shallow saturated layer at the bottom of the column and allowing capillarity to draw water upward, where coarser particle sizes formed the bottom layers with finer particles sizes forming the layers above. The depth of each layer was designed to optimize water content based on measurements and modeling of the wetting water retention curves. Layer boundaries were chosen to retain saturation between 50 and 85 percent. The saturation distribution was verified by dual-probe heat-pulse water-content sensors. The nutrient experiment involved embedding slow release fertilizer in the porous media in order to detect variations in electrical resistivity versus time during the release, diffusion and uptake of

  16. Modeling and optimization of the line-driver power consumption in xDSL systems

    NASA Astrophysics Data System (ADS)

    Wolkerstorfer, Martin; Trautmann, Steffen; Nordström, Tomas; Putra, Bakti D.

    2012-12-01

    Optimization of the power spectrum alleviates the crosstalk noise in digital subscriber lines (DSL) and thereby reduces their power consumption at present. In order to truly assess the DSL system power consumption, this article presents realistic line driver (LD) power consumption models. These are applicable to any DSL system and extend previous models by parameterizing various circuit-level non-idealities. Based on the model of a class-AB LD we analyze the multi-user power spectrum optimization problem and propose novel algorithms for its global or approximate solution. The thereby obtained simulation results support our claim that this problem can be simplified with negligible performance loss by neglecting the LD model. This motivates the usage of established spectral optimization algorithms, which are shown to significantly reduce the LD power consumption compared to static spectrum management.

  17. Modelling the Transfer and Retention of Nutrients in the Drainage Network of the Danube River

    NASA Astrophysics Data System (ADS)

    Garnier, J.; Billen, G.; Hannon, E.; Fonbonne, S.; Videnina, Y.; Soulie, M.

    2002-03-01

    The Danube catchment basin (817 000 km 2, 76×10 6 inhabitants) is the major freshwater contributor to the Black Sea (6300 m 3 s -1, 80% of the annual river discharge into the north-western Black Sea). The aim of the modelling approach developed for the Danube River, is to establish how land use and management of the whole watershed are linked to nutrient (N, P, Si) delivery and retention by the river. The approach uses an adaptation of the RIVERSTRAHLER model, which is based on a schematic representation of the drainage network deduced from geomorphological analysis by stream orders. The whole catchment was divided into 10 sub-basins and one branch, to provide a description satisfying both the need to take into account the heterogeneity of the system and the availability of constraints and validation data. On the basis of this description, a hydrological model was developed, which adequately simulated the seasonal variations of the discharge measured at the outlet of the basin. The model itself resulted from the coupling of the hydrological model with a biogeochemical model (RIVE), which takes into account the main ecological processes. It established a link between microscopic processes, their controlling factors and their macroscopic manifestations in terms of nutrient cycling and ecological functioning at the scale of the whole drainage network. The model was validated for the period from 1988 to 1991 on the basis of available observations of the major water-quality variables involved in the eutrophication processes (inorganic nutrients, phytoplankton biomass, dissolved oxygen, etc.). A reasonable agreement was found between the simulations of the model and the observations. Nutrient fluxes to the Black Sea, calculated for our reference period, are in the same range as those obtained via other approaches. Si/P and N/P ratios suggest silicon, rather than phosphorus, limitation for diatoms and phosphorus, rather than nitrogen, limitation for overall phytoplankton

  18. Density outbursts in a food web model with a closed nutrient cycle

    NASA Astrophysics Data System (ADS)

    Szwabiński, Janusz

    2013-09-01

    A spatial three level food web model with a closed nutrient cycle is presented and analyzed via Monte Carlo simulations. The food web consists of three trophic levels. The basal level species (called resources, R) corresponds to primary producers in real ecosystems. The species at an intermediate level (consumers, C) relates to herbivores. It feeds on the resources. The consumers themselves constitute food for the top level species (predators, P), which corresponds to carnivores. The remains of the consumers and predators (detritus, D) provide nutrient for the resources. The time evolution of the model reveals two asymptotic states: an absorbing one with all species being extinct, and a coexisting one, in which concentrations of all species are non-zero. There are two possible ways for the system to reach the absorbing state. In some cases the densities increase very quickly at the beginning of a simulation and then decline slowly and almost monotonically. In others, well pronounced peaks in the R, C and D densities appear regularly before the extinction. Those peaks correspond to density outbursts (waves) traveling through the system. We investigate the mechanisms leading to the waves. In particular, we show that the percolation of the detritus (i.e. the accumulation of nutrients) is necessary for the emergence of the waves. Moreover, our results corroborate the hypothesis that top-level predators play an essential role in maintaining the stability of a food web (top-down control).

  19. Watershed Modeling of Nutrient Transport Covering the Country of Sweden - Scale Transfer in HBV-NP

    NASA Astrophysics Data System (ADS)

    Arheimer, B.; Andersson, L.

    2002-12-01

    Eutrophication of the Baltic Sea and its coastal zone is considered a serious environmental problem. The problems are mainly caused by excessive load of nitrogen (N) and phosphorus (P). To improve the situation new policies including watershed-based water management are implemented. However, this also demands watershed-based knowledge of nutrient transport proc-esses and appropriate tools for landscape planning. A watershed model (HBV-NP) that can be applied both on the local and the national scale has thus been developed to be used both for international reporting and scenario estimates for more efficient nutrient control strategies. The P part is presently developed within the Swedish Water Management Research Program (VASTRA), in which HBV-NP will be used for evaluation of best management practices, and for communication with local stake-holders. The model has recently been applied at the national scale for calculations of flow-normalized annual average of gross load, N retention and net transport, and source apportionment of the N load reaching the sea. In this application (called TRK) several submodels with different levels of process descriptions were linked together. Dynamic and detailed models were included for arable leaching (SOIL-N model), rainfall interpolation, atmospheric deposition (MATCH model), water balance (HBV), and nutrient transformation in groundwater, rivers and lakes (HBV-N). Based on landscape information in GIS, different leaching rates and emissions were assigned to the water discharge from similar landscape elements in 1000 subbasins covering Sweden. Scale transfer was mainly achieved through up-scaling procedures and by using the conceptual model approach for watershed hydrology, including variability parameters that are calibrated for regions. The modeled river flow and N concentrations were validated against time-series from several independent-monitoring stations. A similar national system is now under development for P, including

  20. Glutamate prevents intestinal atrophy via luminal nutrient sensing in a mouse model of total parenteral nutrition

    PubMed Central

    Xiao, Weidong; Feng, Yongjia; Holst, Jens J.; Hartmann, Bolette; Yang, Hua; Teitelbaum, Daniel H.

    2014-01-01

    Small intestine luminal nutrient sensing may be crucial for modulating physiological functions. However, its mechanism of action is incompletely understood. We used a model of enteral nutrient deprivation, or total parenteral nutrition (TPN), resulting in intestinal mucosal atrophy and decreased epithelial barrier function (EBF). We examined how a single amino acid, glutamate (GLM), modulates intestinal epithelial cell (IEC) growth and EBF. Controls were chow-fed mice, T1 receptor-3 (T1R3)-knockout (KO) mice, and treatment with the metabotropic glutamate receptor (mGluR)-5 antagonist MTEP. TPN significantly changed the amount of T1Rs, GLM receptors, and transporters, and GLM prevented these changes. GLM significantly prevented TPN-associated intestinal atrophy (2.5-fold increase in IEC proliferation) and was dependent on up-regulation of the protein kinase pAkt, but independent of T1R3 and mGluR5 signaling. GLM led to a loss of EBF with TPN (60% increase in FITC-dextran permeability, 40% decline in transepithelial resistance); via T1R3, it protected EBF, whereas mGluR5 was associated with EBF loss. GLM led to a decline in circulating glucagon-like peptide 2 (GLP-2) during TPN. The decline was regulated by T1R3 and mGluR5, suggesting a novel negative regulator pathway for IEC proliferation not previously described. Loss of luminal nutrients with TPN administration may widely affect intestinal taste sensing. GLM has previously unrecognized actions on IEC growth and EBF. Restoring luminal sensing via GLM could be a strategy for patients on TPN.—Xiao, W., Feng, Y., Holst, J. J., Hartmann, B., Yang, H., Teitelbaum, D. H. Glutamate prevents intestinal atrophy via luminal nutrient sensing in a mouse model of total parenteral nutrition. PMID:24497581

  1. Modelling Macroalgae Productivity In An Estuary. A Biorremediation To Nutrient Discharges In The Ecosystems.

    NASA Astrophysics Data System (ADS)

    Alvera-Azcárate, A.; Ferreira, J. G.; Nunes, J. P.

    Enhanced nutrient load to estuaries and coastal waters due to anthropogenic activities is damaging aquatic ecosystems, resulting in water pollution and eutrophication prob- lems. It is important to quantify the production of photosynthetic organisms, as they play an important role in controlling nitrogen removal and nitrogen fluxes between the sediments and the water column. In turbid estuaries, such as those on the NE Atlantic coast of Europe, benthic primary producers such as macroalgae may play an important part in carbon fixation and nutrient removal, since pelagic production is often strongly light-limited. Estuarine seaweeds are primarily located in intertidal areas, which are characterised by shallow waters and strong tidal currents. Due to high concentrations of suspended particulate matter in the water column, light is rapidly attenuated, limiting macroal- gae production during part of the tidal cycle. An accurate representation of sediment dynamics is essential for the determination of the light energy available for the algae, which is a key factor in reliable primary production estimates. In tidal flats, the sedi- ment dynamics is made more complex by the formation of tidal pools during low tide, where water quickly becomes clear, allowing more light to penetrate through the water column. In the present work a model is developed to calculate macroalgae production in the intertidal areas of estuaries, considering the factors mentioned above. The model is tested for the Tagus estuary (Portugal), and a Gross Primary Production of 3300 g m-2 y-1 was obtained. That results in a total nitrogen removal of 440 gN m-2 y-1. The results show that the macroalgae community plays an impor- tant role in the nitrogen cycle in estuaries and nutrient export to the open sea, acting as a biorremediation for the increased nutrient loading problem.

  2. Water and Nutrient Balances in a Large Tile-Drained Agricultural Catchment: A Distributed Modeling Study

    SciTech Connect

    Li, Hongyi; Sivapalan, Murugesu; Tian, Fuqiang; Liu, Dengfeng

    2010-11-16

    This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW) approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in central Illinois, mid-west of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter- and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow) and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

  3. A mathematical model for investigating the effect of cluster roots on plant nutrient uptake

    NASA Astrophysics Data System (ADS)

    Zygalakis, K. C.; Roose, T.

    2012-04-01

    Cluster roots are thought to play an important role in mediating nutrient uptake by plants. In this paper we develop a mathematical model for the transport and uptake of phosphate by a single root. Phosphate is assumed to diffuse in the soil fluid phase and can also solubilised due to citrate exudation. Using multiple scale homogenisation techniques we derive an effective model that accounts for the cumulative effect of citrate exudation and phosphate uptake by cluster roots whilst still retaining all the necessary information about the microscale geometry and effects.

  4. Coupling hydrological and impact assessment models to explore nutrient cycling in freshwater systems

    NASA Astrophysics Data System (ADS)

    Bouwman, Lex; van Beek, Rens; Beusen, Arthur; Mogollón, José; Middelburg, Jack

    2016-04-01

    The IMAGE-Global Nutrient Model (GNM) is a new globally distributed, spatially explicit model in which the hydrology model PCR-GLOBWB is coupled to the integrated assessment model IMAGE to simulate nitrogen (N) and phosphorus (P) delivery, and then with a spiraling ecological approach to simulating instream biogeochemistry. Routing the water with dissolved and suspended N and P from upstream grid cells occurs simultaneous with N and P delivery to water bodies within grid cells from diffuse and point sources (wastewater). IMAGE-GNM describes the following diffuse sources associated with the water flow: surface runoff, shallow and deep groundwater, riparian zones. Depending on the landscape features, all these flows may be present within one grid cell. Furthermore, diffuse N and P inputs occur through allochtonous organic matter inputs via litterfall in (temporarily) inundated river floodplains, and atmospheric deposition. In the spiraling concept, the residence time of the water and nutrient uptake velocity determine N and P retention in water bodies. Validation of model results with observations yields acceptable agreement given the global scale of the uncalibrated model. Sensitivity analysis shows shifts in the importance of the different sources, with decreasing importance of natural sources and increasing influence of wastewater and agriculture. IMAGE-GNM can be employed to study the interaction between society and the environment over prolonged time periods. Here we show results for the full 20th century.

  5. Effect of wheat (Triticum aestivum L.) grain color and hardness on the consumption preference of a mouse model system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Wheat (Triticum aestivum L.) grain is a staple food and provides necessary nutrients for human health and nutrition. Yet, flavor differences among wheat varieties are not well understood. Grain flavor and consumption preference can be examined using the house mouse (Mus musculus L.) as a...

  6. Regional assessments of the Nation's water quality—Improved understanding of stream nutrient sources through enhanced modeling capabilities

    USGS Publications Warehouse

    Preston, Stephen D.; Alexander, Richard B.; Woodside, Michael D.

    2011-01-01

    The U.S. Geological Survey (USGS) recently completed assessments of stream nutrients in six major regions extending over much of the conterminous United States. SPARROW (SPAtially Referenced Regressions On Watershed attributes) models were developed for each region to explain spatial patterns in monitored stream nutrient loads in relation to human activities and natural resources and processes. The model information, reported by stream reach and catchment, provides contrasting views of the spatial patterns of nutrient source contributions, including those from urban (wastewater effluent and diffuse runoff from developed land), agricultural (farm fertilizers and animal manure), and specific background sources (atmospheric nitrogen deposition, soil phosphorus, forest nitrogen fixation, and channel erosion).

  7. Nutrient limitation on terrestrial plant growth--modeling the interaction between nitrogen and phosphorus.

    PubMed

    Agren, Göran I; Wetterstedt, J Å Martin; Billberger, Magnus F K

    2012-06-01

    Growth of plants in terrestrial ecosystems is often limited by the availability of nitrogen (N) or phosphorous (P) Liebig's law of the minimum states that the nutrient in least supply relative to the plant's requirement will limit the plant's growth. An alternative to the law of the minimum is the multiple limitation hypothesis (MLH) which states that plants adjust their growth patterns such that they are limited by several resources simultaneously. We use a simple model of plant growth and nutrient uptake to explore the consequences for the plant's relative growth rate of letting plants invest differentially in N and P uptake. We find a smooth transition between limiting elements, in contrast to the strict transition in Liebig's law of the minimum. At N : P supply ratios where the two elements simultaneously limit growth, an increase in either of the nutrients will increase the growth rate because more resources can be allocated towards the limiting element, as suggested by the multiple limitation hypothesis. However, the further the supply ratio deviates from these supply rates, the more the plants will follow the law of the minimum. Liebig's law of the minimum will in many cases be a useful first-order approximation.

  8. Modeling carbon-nutrient interactions during the early recovery of tundra after fire.

    PubMed

    Jiang, Yueyang; Rastetter, Edward B; Rocha, Adrian V; Pearce, Andrea R; Kwiatkowski, Bonnie L; Shaver, Gaius R

    2015-09-01

    Fire frequency has dramatically increased in the tundra of northern Alaska, USA, which has major implications for the carbon budget of the region and the functioning of these ecosystems, which support important wildlife species. We investigated the postfire succession of plant and soil carbon (C), nitrogen (N), and phosphorus (P) fluxes and stocks along a burn severity gradient in the 2007 Anaktuvuk River fire scar in northern Alaska. Modeling results indicated that the early regrowth of postfire tundra vegetation was limited primarily by its canopy photosynthetic potential, rather than nutrient availability, because of the initially low leaf area and relatively high inorganic N and P concentrations in soil. Our simulations indicated that the postfire recovery of tundra vegetation was sustained predominantly by the uptake of residual inorganic N (i.e., in the remaining ash), and the redistribution of N and P from soil organic matter to vegetation. Although residual nutrients in ash were higher in the severe burn than the moderate burn, the moderate burn recovered faster because of the higher remaining biomass and consequent photosynthetic potential. Residual nutrients in ash allowed both burn sites to recover and exceed the unburned site in both aboveground biomass and production five years after the fire. The investigation of interactions among postfire C, N, and P cycles has contributed to a mechanistic understanding of the response of tundra ecosystems to fire disturbance. Our study provided insight on how the trajectory of recovery of tundra from wildfire is regulated during early succession.

  9. Identification of nutrient and physical seed trait QTL in the model legume Lotus japonicus.

    PubMed

    Klein, Melinda A; Grusak, Michael A

    2009-08-01

    Legume seeds have the potential to provide a significant portion of essential micronutrients to the human diet. To identify the genetic basis for seed nutrient density, quantitative trait locus (QTL) analysis was conducted with the Miyakojima MG-20 x Gifu B-129 recombinant inbred population from the model legume Lotus japonicus. This population was grown to seed under greenhouse conditions in 2006 and 2007. Phenotypic data were collected for seed calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P), sulfur (S), and zinc (Zn) concentrations and content. Data for physical seed traits (average seed mass and seed-pod allocation values) were also collected. Based on these phenotypic data, QTL analyses identified 103 QTL linked to 55 different molecular markers. Transgressive segregation, identified within this recombinant inbred population for both seed nutrient and physical traits, suggests new allelic combinations are available for agronomic trait improvement. QTL co-localization was also seen, suggesting that common transport processes might contribute to seed nutrient loading. Identification of loci involved in seed mineral density can be an important first step in identifying the genetic factors and, consequently, the physiological processes involved in mineral distribution to developing seeds. Longer term research efforts will focus on facilitating agronomic breeding efforts through ortholog identification in related crop legumes.

  10. Nutrients from dairy foods are difficult to replace in diets of Americans: food pattern modeling and an analyses of the National Health and Nutrition Examination Survey 2003-2006.

    PubMed

    Fulgoni, Victor L; Keast, Debra R; Auestad, Nancy; Quann, Erin E

    2011-10-01

    Because dairy products provide shortfall nutrients (eg, calcium, potassium, and vitamin D) and other important nutrients, this study hypothesized that it would be difficult for Americans to meet nutritional requirements for these nutrients in the absence of dairy product consumption or when recommended nondairy calcium sources are consumed. To test this hypothesis, MyPyramid dietary pattern modeling exercises and an analyses of data from the National Health and Nutrition Examination Survey 2003-2006 were conducted in those aged at least 2 years (n = 16 822). Impact of adding or removing 1 serving of dairy, removing all dairy, and replacing dairy with nondairy calcium sources was evaluated. Dietary pattern modeling indicated that at least 3 servings of dairy foods are needed to help individuals meet recommendations for nutrients, such as calcium and magnesium, and 4 servings may be needed to help some groups meet potassium recommendations. A calcium-equivalent serving of dairy requires 1.1 servings of fortified soy beverage, 0.6 serving of fortified orange juice, 1.2 servings of bony fish, or 2.2 servings of leafy greens. The replacement of dairy with calcium-equivalent foods alters the overall nutritional profile of the diet and affects nutrients including protein, potassium, magnesium, phosphorus, riboflavin, vitamins A, D and B(12). Similar modeling exercises using consumption data from the National Health and Nutrition Examination Survey also demonstrated that nondairy calcium replacement foods are not a nutritionally equivalent substitute for dairy products. In conclusion, although it is possible to meet calcium intake recommendations without consuming dairy foods, calcium replacement foods are not a nutritionally equivalent substitute for dairy foods and consumption of a calcium-equivalent amount of some nondairy foods is unrealistic.

  11. Nutrients from dairy foods are difficult to replace in diets of Americans: food pattern modeling and an analyses of the National Health and Nutrition Examination Survey 2003-2006.

    PubMed

    Fulgoni, Victor L; Keast, Debra R; Auestad, Nancy; Quann, Erin E

    2011-10-01

    Because dairy products provide shortfall nutrients (eg, calcium, potassium, and vitamin D) and other important nutrients, this study hypothesized that it would be difficult for Americans to meet nutritional requirements for these nutrients in the absence of dairy product consumption or when recommended nondairy calcium sources are consumed. To test this hypothesis, MyPyramid dietary pattern modeling exercises and an analyses of data from the National Health and Nutrition Examination Survey 2003-2006 were conducted in those aged at least 2 years (n = 16 822). Impact of adding or removing 1 serving of dairy, removing all dairy, and replacing dairy with nondairy calcium sources was evaluated. Dietary pattern modeling indicated that at least 3 servings of dairy foods are needed to help individuals meet recommendations for nutrients, such as calcium and magnesium, and 4 servings may be needed to help some groups meet potassium recommendations. A calcium-equivalent serving of dairy requires 1.1 servings of fortified soy beverage, 0.6 serving of fortified orange juice, 1.2 servings of bony fish, or 2.2 servings of leafy greens. The replacement of dairy with calcium-equivalent foods alters the overall nutritional profile of the diet and affects nutrients including protein, potassium, magnesium, phosphorus, riboflavin, vitamins A, D and B(12). Similar modeling exercises using consumption data from the National Health and Nutrition Examination Survey also demonstrated that nondairy calcium replacement foods are not a nutritionally equivalent substitute for dairy products. In conclusion, although it is possible to meet calcium intake recommendations without consuming dairy foods, calcium replacement foods are not a nutritionally equivalent substitute for dairy foods and consumption of a calcium-equivalent amount of some nondairy foods is unrealistic. PMID:22074800

  12. Application of the general model 'biological nutrient removal model no. 1' to upgrade two full-scale WWTPs.

    PubMed

    Ruano, M V; Serralta, J; Ribes, J; Garcia-Usach, F; Bouzas, A; Barat, R; Seco, A; Ferrer, J

    2012-01-01

    In this paper, two practical case studies for upgrading two wastewater treatment plants (WWTPs) using the general model BNRM 1 (Biological Nutrient Removal Model No. 1) are presented. In the first case study, the Tarragona WWTP was upgraded by reducing the phosphorus load to the anaerobic digester in order to minimize the precipitation problems. Phosphorus load reduction was accomplished by mixing the primary sludge and the secondary sludge and by elutriating the mixed sludge. In the second case study, the Alcantarilla WWTP, the nutrient removal was enhanced by maintaining a relatively low dissolved oxygen concentration in Stage A to maintain the acidogenic bacteria activity. The VFA produced in Stage A favour the denitrification process and biological phosphorus removal in Stage B. These case studies demonstrate the benefits of using the general model BNRMI to simulate settling processes and biological processes related to both anaerobic and aerobic bacteria in the same process unit.

  13. Image-based modelling of nutrient movement in and around the rhizosphere.

    PubMed

    Daly, Keith R; Keyes, Samuel D; Masum, Shakil; Roose, Tiina

    2016-02-01

    In this study, we developed a spatially explicit model for nutrient uptake by root hairs based on X-ray computed tomography images of the rhizosphere soil structure. This work extends our previous work to larger domains and hence is valid for longer times. Unlike the model used previously, which considered only a small region of soil about the root, we considered an effectively infinite volume of bulk soil about the rhizosphere. We asked the question: At what distance away from root surfaces do the specific structural features of root-hair and soil aggregate morphology not matter because average properties start dominating the nutrient transport? The resulting model was used to capture bulk and rhizosphere soil properties by considering representative volumes of soil far from the root and adjacent to the root, respectively. By increasing the size of the volumes that we considered, the diffusive impedance of the bulk soil and root uptake were seen to converge. We did this for two different values of water content. We found that the size of region for which the nutrient uptake properties converged to a fixed value was dependent on the water saturation. In the fully saturated case, the region of soil we needed to consider was only of radius 1.1mm for poorly soil-mobile species such as phosphate. However, in the case of a partially saturated medium (relative saturation 0.3), we found that a radius of 1.4mm was necessary. This suggests that, in addition to the geometrical properties of the rhizosphere, there is an additional effect of soil moisture properties, which extends further from the root and may relate to other chemical changes in the rhizosphere. The latter were not explicitly included in our model.

  14. Image-based modelling of nutrient movement in and around the rhizosphere

    PubMed Central

    Daly, Keith R.; Keyes, Samuel D.; Masum, Shakil; Roose, Tiina

    2016-01-01

    In this study, we developed a spatially explicit model for nutrient uptake by root hairs based on X-ray computed tomography images of the rhizosphere soil structure. This work extends our previous work to larger domains and hence is valid for longer times. Unlike the model used previously, which considered only a small region of soil about the root, we considered an effectively infinite volume of bulk soil about the rhizosphere. We asked the question: At what distance away from root surfaces do the specific structural features of root-hair and soil aggregate morphology not matter because average properties start dominating the nutrient transport? The resulting model was used to capture bulk and rhizosphere soil properties by considering representative volumes of soil far from the root and adjacent to the root, respectively. By increasing the size of the volumes that we considered, the diffusive impedance of the bulk soil and root uptake were seen to converge. We did this for two different values of water content. We found that the size of region for which the nutrient uptake properties converged to a fixed value was dependent on the water saturation. In the fully saturated case, the region of soil we needed to consider was only of radius 1.1mm for poorly soil-mobile species such as phosphate. However, in the case of a partially saturated medium (relative saturation 0.3), we found that a radius of 1.4mm was necessary. This suggests that, in addition to the geometrical properties of the rhizosphere, there is an additional effect of soil moisture properties, which extends further from the root and may relate to other chemical changes in the rhizosphere. The latter were not explicitly included in our model. PMID:26739861

  15. Image-based modelling of nutrient movement in and around the rhizosphere.

    PubMed

    Daly, Keith R; Keyes, Samuel D; Masum, Shakil; Roose, Tiina

    2016-02-01

    In this study, we developed a spatially explicit model for nutrient uptake by root hairs based on X-ray computed tomography images of the rhizosphere soil structure. This work extends our previous work to larger domains and hence is valid for longer times. Unlike the model used previously, which considered only a small region of soil about the root, we considered an effectively infinite volume of bulk soil about the rhizosphere. We asked the question: At what distance away from root surfaces do the specific structural features of root-hair and soil aggregate morphology not matter because average properties start dominating the nutrient transport? The resulting model was used to capture bulk and rhizosphere soil properties by considering representative volumes of soil far from the root and adjacent to the root, respectively. By increasing the size of the volumes that we considered, the diffusive impedance of the bulk soil and root uptake were seen to converge. We did this for two different values of water content. We found that the size of region for which the nutrient uptake properties converged to a fixed value was dependent on the water saturation. In the fully saturated case, the region of soil we needed to consider was only of radius 1.1mm for poorly soil-mobile species such as phosphate. However, in the case of a partially saturated medium (relative saturation 0.3), we found that a radius of 1.4mm was necessary. This suggests that, in addition to the geometrical properties of the rhizosphere, there is an additional effect of soil moisture properties, which extends further from the root and may relate to other chemical changes in the rhizosphere. The latter were not explicitly included in our model. PMID:26739861

  16. Global patterns of phytoplankton nutrient and light colimitation inferred from an optimality-based model

    NASA Astrophysics Data System (ADS)

    Arteaga, Lionel; Pahlow, Markus; Oschlies, Andreas

    2014-07-01

    The widely used concept of constant "Redfield" phytoplankton stoichiometry is often applied for estimating which nutrient limits phytoplankton growth in the surface ocean. Culture experiments, in contrast, show strong relations between growth conditions and cellular stoichiometry with often substantial deviations from Redfield stoichiometry. Here we investigate to what extent both views agree by analyzing remote sensing and in situ data with an optimality-based model of nondiazotrophic phytoplankton growth in order to infer seasonally varying patterns of colimitation by light, nitrogen (N), and phosphorus (P) in the global ocean. Our combined model-data analysis suggests strong N and N-P colimitation in the tropical ocean, seasonal light, and N-P colimitation in the Northern Hemisphere, and strong light limitation only during winter in the Southern Ocean. The eastern equatorial Pacific appears as the only ocean area that is essentially not limited by N, P, or light. Even though our optimality-based approach specifically accounts for flexible stoichiometry, inferred patterns of N and P limitation are to some extent consistent with those obtained from an analysis of surface inorganic nutrients with respect to the Redfield N:P ratio. Iron is not part of our analysis, implying that we cannot accurately predict N cell quotas in high-nutrient, low-chlorophyll regions. Elsewhere, we do not expect a major effect of iron on the relative distribution of N, P, and light colimitation areas. The relative importance of N, P, and light in limiting phytoplankton growth diagnosed here by combining observations and an optimal growth model provides a useful constraint for models used to predict future marine biological production under changing environmental conditions. 2014. American Geophysical Union. All Rights Reserved.

  17. Multiple soil nutrient competition between plants, microbes, and mineral surfaces: model development, parameterization, and example applications in several tropical forests

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Riley, W. J.; Tang, J.; Koven, C. D.

    2016-01-01

    Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3- and POx; representing the sum of PO43-, HPO42- and H2PO4-) and five potential competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus and NH4+ pools at a tropical forest site (Tapajos). The overall model uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer-substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results also imply that under strong nutrient limitation, relative competitiveness depends strongly on the competitor functional traits (affinity and nutrient carrier enzyme abundance). We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii and Puerto Rico) not used in model development or calibration. Under soil inorganic nitrogen and phosphorus elevated conditions, the model accurately

  18. Multiple soil nutrient competition between plants, microbes, and mineral surfaces: model development, parameterization, and example applications in several tropical forests

    DOE PAGES

    Zhu, Q.; Riley, W. J.; Tang, J.; Koven, C. D.

    2016-01-18

    Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3− and POx; representing the sum of PO43−, HPO42− and H2PO4−) and five potential competitors (plantmore » roots, decomposing microbes, nitrifiers, denitrifiers and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus and NH4+ pools at a tropical forest site (Tapajos). The overall model uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer–substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results also imply that under strong nutrient limitation, relative competitiveness depends strongly on the competitor functional traits (affinity and nutrient carrier enzyme abundance). We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii and Puerto Rico) not used in model development or calibration. Under soil inorganic nitrogen and phosphorus elevated conditions, the model accurately replicated the experimentally observed

  19. NEW FEATURES OF SIMSAFADIM NUMERICAL MODEL: inclusion of nutrients as a carbonate production factor and sediment compaction

    NASA Astrophysics Data System (ADS)

    Clavera-Gispert, R.; Carmona, A.; Tolosana-Delgado, R.; Gratacós, O.; Bitzer, K.

    2009-04-01

    Carbonate-sedimentary environments are characterized by different groups of organisms living together and competing for space, nutrients and other life-determining factors. The 3D simulation model SIMSAFADIM is used to simulate these environments. In its original state, SIMSAFADIM was a 3D forward process-based model for simulation of stratigraphic architecture and facies distribution in sedimentary basins. It was developed by Bitzer, Salas and Gratacós and considers clastic and carbonate sediments. In a first step, the model simulated carbonate production and sedimentation controlled by water depth, presence of clastic sediments, carbonate mud and predator-prey factors among three species. However other factors are important in carbonate producer species like nutrient supply, which is included in the new version of this code. Nutrients play an important role in species life, because nutrients control which species can appear and how do they grow. Each species needs a specific range of nutrient concentration to grow. Then marine environments are classified in three main groups, depending on their nutrients concentration: oligotrophic, mesotrophic and eutrophic. To model the new environmental variable, the code works with nutrients like any other 'sediment'. These are incorporated into the fluid and flow like clastic sediments, but nutrients are consumed by species and not settled down. The code considers a special situation, when a marine transgression occurs. In this case, when the sea level rises and floods new areas, these flooded areas contribute with an extra concentration of nutrients inflow. Furthermore the program adds a new module to calculate compaction of clastic and carbonate sediments using the deMarsily formulation that follows Terzaghi's consolidation theory.

  20. Dynamics of a producer-grazer model incorporating the effects of excess food nutrient content on grazer's growth.

    PubMed

    Peace, Angela; Wang, Hao; Kuang, Yang

    2014-09-01

    Modeling under the framework of ecological stoichiometric allows the investigation of the effects of food quality on food web population dynamics. Recent discoveries in ecological stoichiometry suggest that grazer dynamics are affected by insufficient food nutrient content (low phosphorus (P)/carbon (C) ratio) as well as excess food nutrient content (high P:C). This phenomenon is known as the "stoichiometric knife edge." While previous models have captured this phenomenon, they do not explicitly track P in the producer or in the media that supports the producer, which brings questions to the validity of their predictions. Here, we extend a Lotka-Volterra-type stoichiometric model by mechanistically deriving and tracking P in the producer and free P in the environment in order to investigate the growth response of Daphnia to algae of varying P:C ratios. Bifurcation analysis and numerical simulations of the full model, that explicitly tracks phosphorus, lead to quantitative different predictions than previous models that neglect to track free nutrients. The full model shows that the fate of the grazer population can be very sensitive to excess nutrient concentrations. Dynamical free nutrient pool seems to induce extreme grazer population density changes when total nutrient is in an intermediate range. PMID:25124765

  1. Global Warmth and Nutrient Trapping Enhance End-Paleozoic Euxinia in an Earth System Model

    NASA Astrophysics Data System (ADS)

    Meyer, K. M.; Kump, L. R.; Ridgwell, A.

    2007-12-01

    The end-Permian mass extinction occurred during an interval characterized by global warmth and falling atmospheric oxygen levels. Although the cause of the extinction remains unresolved, geochemical evidence suggests that the event coincided with widespread anoxia and possible euxinia (anoxic and sulfidic waters). A combination of warm surface ocean temperatures, low atmospheric oxygen content, and high O2 demand in the deep ocean likely induced anoxia. Anaerobic organic matter remineralization by bacterial sulfate reduction then produced euxinic conditions. Phosphate release from surface sediments and decreased phosphate burial under a sulfidic water column further enhanced oceanic euxinia through positive feedbacks to primary productivity. We hypothesize that late Paleozoic climate and geography favored marine euxinia, a potential kill mechanism for the extinction event. Here we use earth system modelling to explore the physical and biogeochemical conditions necessary for the development of intense euxinia during the end-Permian. We use the end-Permian configuration of GENIE (www.genie.ac.uk), an energy-moisture-balance atmospheric model coupled to a 3-D, non-eddy-resolving, frictional geostrophic model to investigate the transition to marine anoxia and euxinia in a greenhouse world. Equilibrium model simulations over a range of oceanic phosphate concentrations relate oceanic nutrient status to the buildup of euxinia and attendant hydrogen sulfide release to the atmosphere. Addition of a marine nitrogen cycle suggests that microbial denitrification reduces, but does not prevent H2S buildup. Deep-ocean hydrogen sulfide appears with a doubling of phosphate, and localized photic zone euxinia develops with a tripling of phosphate. The greatest surface water H2S concentrations are observed in upwelling zones and in the Paleo-Tethys Ocean, where nutrient trapping results in elevated phosphate concentrations. Significant hydrogen sulfide fluxes to the atmosphere result

  2. A novel cost based model for energy consumption in cloud computing.

    PubMed

    Horri, A; Dastghaibyfard, Gh

    2015-01-01

    Cloud data centers consume enormous amounts of electrical energy. To support green cloud computing, providers also need to minimize cloud infrastructure energy consumption while conducting the QoS. In this study, for cloud environments an energy consumption model is proposed for time-shared policy in virtualization layer. The cost and energy usage of time-shared policy were modeled in the CloudSim simulator based upon the results obtained from the real system and then proposed model was evaluated by different scenarios. In the proposed model, the cache interference costs were considered. These costs were based upon the size of data. The proposed model was implemented in the CloudSim simulator and the related simulation results indicate that the energy consumption may be considerable and that it can vary with different parameters such as the quantum parameter, data size, and the number of VMs on a host. Measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment. Also, measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment.

  3. A novel cost based model for energy consumption in cloud computing.

    PubMed

    Horri, A; Dastghaibyfard, Gh

    2015-01-01

    Cloud data centers consume enormous amounts of electrical energy. To support green cloud computing, providers also need to minimize cloud infrastructure energy consumption while conducting the QoS. In this study, for cloud environments an energy consumption model is proposed for time-shared policy in virtualization layer. The cost and energy usage of time-shared policy were modeled in the CloudSim simulator based upon the results obtained from the real system and then proposed model was evaluated by different scenarios. In the proposed model, the cache interference costs were considered. These costs were based upon the size of data. The proposed model was implemented in the CloudSim simulator and the related simulation results indicate that the energy consumption may be considerable and that it can vary with different parameters such as the quantum parameter, data size, and the number of VMs on a host. Measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment. Also, measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment. PMID:25705716

  4. A Novel Cost Based Model for Energy Consumption in Cloud Computing

    PubMed Central

    Horri, A.; Dastghaibyfard, Gh.

    2015-01-01

    Cloud data centers consume enormous amounts of electrical energy. To support green cloud computing, providers also need to minimize cloud infrastructure energy consumption while conducting the QoS. In this study, for cloud environments an energy consumption model is proposed for time-shared policy in virtualization layer. The cost and energy usage of time-shared policy were modeled in the CloudSim simulator based upon the results obtained from the real system and then proposed model was evaluated by different scenarios. In the proposed model, the cache interference costs were considered. These costs were based upon the size of data. The proposed model was implemented in the CloudSim simulator and the related simulation results indicate that the energy consumption may be considerable and that it can vary with different parameters such as the quantum parameter, data size, and the number of VMs on a host. Measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment. Also, measured results validate the model and demonstrate that there is a tradeoff between energy consumption and QoS in the cloud environment. PMID:25705716

  5. Partial validation of the Dutch model for emission and transport of nutrients (STONE).

    PubMed

    Overbeek, G B; Tiktak, A; Beusen, A H; van Puijenbroek, P J

    2001-11-17

    The Netherlands has to cope with large losses of N and P to groundwater and surface water. Agriculture is the dominant source of these nutrients, particularly with reference to nutrient excretion due to intensive animal husbandry in combination with fertilizer use. The Dutch government has recently launched a stricter eutrophication abatement policy to comply with the EC nitrate directive. The Dutch consensus model for N and P emission to groundwater and surface water (STONE) has been developed to evaluate the environmental benefits of abatement plans. Due to the possibly severe socioeconomic consequences of eutrophication abatement plans, it is of utmost importance that the model is thoroughly validated. Because STONE is applied on a nationwide scale, the model validation has also been carried out on this scale. For this purpose the model outputs were compared with lumped results from monitoring networks in the upper groundwater and in surface waters. About 13,000 recent point source observations of nitrate in the upper groundwater were available, along with several hundreds of observations showing N and P in local surface water systems. Comparison of observations from the different spatial scales available showed the issue of scale to be important. Scale issues will be addressed in the next stages of the validation study.

  6. Avocado consumption is associated with better diet quality and nutrient intake, and lower metabolic syndrome risk in US adults: results from the National Health and Nutrition Examination Survey (NHANES) 2001–2008

    PubMed Central

    2013-01-01

    Background Avocados contain monounsaturated fatty acids (MUFA) dietary fiber, essential nutrients and phytochemicals. However, no epidemiologic data exist on their effects on diet quality, weight management and other metabolic disease risk factors. The objective of this research was to investigate the relationships between avocado consumption and overall diet quality, energy and nutrient intakes, physiological indicators of health, and risk of metabolic syndrome. Methods Avocado consumption and nutrition data were based on 24-hour dietary recalls collected by trained NHANES interviewers using the USDA Automated Multiple Pass Method (AMPM). Physiological data were collected from physical examinations conducted in NHANES Mobile Examination Centers. Diet quality was calculated using the USDA’s Healthy Eating Index-2005. Subjects included 17,567 US adults  ≥ 19 years of age (49% female), including 347 avocado consumers (50% female), examined in NHANES 2001–2008. Least square means, standard errors, and ANOVA were determined using appropriate sample weights, with adjustments for age, gender, ethnicity, and other covariates depending on dependent variable of interest. Results Avocado consumers had significantly higher intakes of vegetables (p < 0.05); fruit, diet quality, total fat, monounsaturated and polyunsaturated fats, dietary fiber, vitamins E, K, magnesium, and potassium (p < 0.0001); vitamin K (p = 0.0013); and lower intakes of added sugars (p < 0.0001). No significant differences were seen in calorie or sodium intakes. Body weight, BMI, and waist circumference were significantly lower (p < 0.01), and HDL-C was higher (p < 0.01) in avocado consumers. The odds ratio for metabolic syndrome was 50% (95th CI: 0.32-0.72) lower in avocado consumers vs. non-consumers. Conclusions Avocado consumption is associated with improved overall diet quality, nutrient intake, and reduced risk of metabolic syndrome. Dietitians should be aware of

  7. A Eulerian nutrient to fish model of the Baltic Sea — A feasibility-study

    NASA Astrophysics Data System (ADS)

    Radtke, Hagen; Neumann, Thomas; Fennel, Wolfgang

    2013-09-01

    A nutrient-to-fish-model with an explicit two-way interaction between a biogeochemical model of the lower food web and a fish model component is presented for the example of the Baltic Sea, demonstrating the feasibility of a consistent coupling of the upper and lower parts of the food web in a Eulerian model system. In the Baltic Sea, the fish stock is dominated by two prey species (sprat and herring) and one predator (cod). The dynamics of the fish model is driven by size (mass-class) dependent predator-prey interactions while the interaction between the biogeochemical and Fish model component is established through feeding of prey fish on zooplankton and recycling of fish biomass to nutrients and detritus. The fish model component is coupled to an advanced three dimensional biogeochemical model (ERGOM, Neumann et al., 2002). A horizontally explicit representation of fish requires the implementation of fish behavior. As a first step, we propose an algorithm to stimulate fish migration by letting the fish follow the food. Moreover, fish species are guided to their respective spawning areas. Results of first three-dimensional simulations are presented with emphasis on the transport of matter by moving fish. The spawning areas of cod and sprat are in the deep basins, which are not well reached by advective transport. Hence the deposition of matter in these areas by spawning fish could play some role in the distribution of matter. The approach is not limited to applications for the Baltic and the model can be transferred also to other systems.

  8. Modeling greenhouse gas emissions and nutrient transport in managed arable soils with a fully coupled hydrology-biogeochemical modeling system

    NASA Astrophysics Data System (ADS)

    Haas, Edwin; Klatt, Steffen; Kiese, Ralf; Butterbach-Bahl, Klaus; Kraft, Philipp; Breuer, Lutz

    2015-04-01

    The use of mineral nitrogen fertilizer sustains the global food production and therefore the livelihood of human kind. The rise in world population will put pressure on the global agricultural system to increase its productivity leading most likely to an intensification of mineral nitrogen fertilizer use. The fate of excess nitrogen and its distribution within landscapes is manifold. Process knowledge on the site scale has rapidly grown in recent years and models have been developed to simulate carbon and nitrogen cycling in managed ecosystems on the site scale. Despite first regional studies, the carbon and nitrogen cycling on the landscape or catchment scale is not fully understood. In this study we present a newly developed modelling approach by coupling the fully distributed hydrology model CMF (catchment modelling framework) to the process based regional ecosystem model LandscapeDNDC for the investigation of hydrological processes and carbon and nitrogen transport and cycling, with a focus on nutrient displacement and resulting greenhouse gas emissions in various virtual landscapes / catchment to demonstrate the capabilities of the modelling system. The modelling system was applied to simulate water and nutrient transport at the at the Yanting Agro-ecological Experimental Station of Purple Soil, Sichuan province, China. The catchment hosts cypress forests on the outer regions, arable fields on the sloping croplands cultivated with wheat-maize rotations and paddy rice fields in the lowland. The catchment consists of 300 polygons vertically stratified into 10 soil layers. Ecosystem states (soil water content and nutrients) and fluxes (evapotranspiration) are exchanged between the models at high temporal scales (hourly to daily) forming a 3-dimensional model application. The water flux and nutrients transport in the soil is modelled using a 3D Richards/Darcy approach for subsurface fluxes with a kinematic wave approach for surface water runoff and the

  9. Underestimation of boreal soil carbon stocks by mathematical soil carbon models linked to soil nutrient status

    NASA Astrophysics Data System (ADS)

    Ťupek, Boris; Ortiz, Carina A.; Hashimoto, Shoji; Stendahl, Johan; Dahlgren, Jonas; Karltun, Erik; Lehtonen, Aleksi

    2016-08-01

    Inaccurate estimate of the largest terrestrial carbon pool, soil organic carbon (SOC) stock, is the major source of uncertainty in simulating feedback of climate warming on ecosystem-atmosphere carbon dioxide exchange by process-based ecosystem and soil carbon models. Although the models need to simplify complex environmental processes of soil carbon sequestration, in a large mosaic of environments a missing key driver could lead to a modeling bias in predictions of SOC stock change.We aimed to evaluate SOC stock estimates of process-based models (Yasso07, Q, and CENTURY soil sub-model v4) against a massive Swedish forest soil inventory data set (3230 samples) organized by a recursive partitioning method into distinct soil groups with underlying SOC stock development linked to physicochemical conditions.For two-thirds of measurements all models predicted accurate SOC stock levels regardless of the detail of input data, e.g., whether they ignored or included soil properties. However, in fertile sites with high N deposition, high cation exchange capacity, or moderately increased soil water content, Yasso07 and Q models underestimated SOC stocks. In comparison to Yasso07 and Q, accounting for the site-specific soil characteristics (e. g. clay content and topsoil mineral N) by CENTURY improved SOC stock estimates for sites with high clay content, but not for sites with high N deposition.Our analysis suggested that the soils with poorly predicted SOC stocks, as characterized by the high nutrient status and well-sorted parent material, indeed have had other predominant drivers of SOC stabilization lacking in the models, presumably the mycorrhizal organic uptake and organo-mineral stabilization processes. Our results imply that the role of soil nutrient status as regulator of organic matter mineralization has to be re-evaluated, since correct SOC stocks are decisive for predicting future SOC change and soil CO2 efflux.

  10. A mechanistic model for electricity consumption on dairy farms: definition, validation, and demonstration.

    PubMed

    Upton, J; Murphy, M; Shalloo, L; Groot Koerkamp, P W G; De Boer, I J M

    2014-01-01

    Our objective was to define and demonstrate a mechanistic model that enables dairy farmers to explore the impact of a technical or managerial innovation on electricity consumption, associated CO2 emissions, and electricity costs. We, therefore, (1) defined a model for electricity consumption on dairy farms (MECD) capable of simulating total electricity consumption along with related CO2 emissions and electricity costs on dairy farms on a monthly basis; (2) validated the MECD using empirical data of 1yr on commercial spring calving, grass-based dairy farms with 45, 88, and 195 milking cows; and (3) demonstrated the functionality of the model by applying 2 electricity tariffs to the electricity consumption data and examining the effect on total dairy farm electricity costs. The MECD was developed using a mechanistic modeling approach and required the key inputs of milk production, cow number, and details relating to the milk-cooling system, milking machine system, water-heating system, lighting systems, water pump systems, and the winter housing facilities as well as details relating to the management of the farm (e.g., season of calving). Model validation showed an overall relative prediction error (RPE) of less than 10% for total electricity consumption. More than 87% of the mean square prediction error of total electricity consumption was accounted for by random variation. The RPE values of the milk-cooling systems, water-heating systems, and milking machine systems were less than 20%. The RPE values for automatic scraper systems, lighting systems, and water pump systems varied from 18 to 113%, indicating a poor prediction for these metrics. However, automatic scrapers, lighting, and water pumps made up only 14% of total electricity consumption across all farms, reducing the overall impact of these poor predictions. Demonstration of the model showed that total farm electricity costs increased by between 29 and 38% by moving from a day and night tariff to a flat

  11. A mechanistic model for electricity consumption on dairy farms: definition, validation, and demonstration.

    PubMed

    Upton, J; Murphy, M; Shalloo, L; Groot Koerkamp, P W G; De Boer, I J M

    2014-01-01

    Our objective was to define and demonstrate a mechanistic model that enables dairy farmers to explore the impact of a technical or managerial innovation on electricity consumption, associated CO2 emissions, and electricity costs. We, therefore, (1) defined a model for electricity consumption on dairy farms (MECD) capable of simulating total electricity consumption along with related CO2 emissions and electricity costs on dairy farms on a monthly basis; (2) validated the MECD using empirical data of 1yr on commercial spring calving, grass-based dairy farms with 45, 88, and 195 milking cows; and (3) demonstrated the functionality of the model by applying 2 electricity tariffs to the electricity consumption data and examining the effect on total dairy farm electricity costs. The MECD was developed using a mechanistic modeling approach and required the key inputs of milk production, cow number, and details relating to the milk-cooling system, milking machine system, water-heating system, lighting systems, water pump systems, and the winter housing facilities as well as details relating to the management of the farm (e.g., season of calving). Model validation showed an overall relative prediction error (RPE) of less than 10% for total electricity consumption. More than 87% of the mean square prediction error of total electricity consumption was accounted for by random variation. The RPE values of the milk-cooling systems, water-heating systems, and milking machine systems were less than 20%. The RPE values for automatic scraper systems, lighting systems, and water pump systems varied from 18 to 113%, indicating a poor prediction for these metrics. However, automatic scrapers, lighting, and water pumps made up only 14% of total electricity consumption across all farms, reducing the overall impact of these poor predictions. Demonstration of the model showed that total farm electricity costs increased by between 29 and 38% by moving from a day and night tariff to a flat

  12. A scalable model for methane consumption in arctic mineral soils

    NASA Astrophysics Data System (ADS)

    Oh, Youmi; Stackhouse, Brandon; Lau, Maggie C. Y.; Xu, Xiangtao; Trugman, Anna T.; Moch, Jonathan; Onstott, Tullis C.; Jørgensen, Christian J.; D'Imperio, Ludovica; Elberling, Bo; Emmerton, Craig A.; St. Louis, Vincent L.; Medvigy, David

    2016-05-01

    Recent field studies have documented a surprisingly strong and consistent methane sink in arctic mineral soils, thought to be due to high-affinity methanotrophy. However, the distinctive physiology of these methanotrophs is poorly represented in mechanistic methane models. We developed a new model, constrained by microcosm experiments, to simulate the activity of high-affinity methanotrophs. The model was tested against soil core-thawing experiments and field-based measurements of methane fluxes and was compared to conventional mechanistic methane models. Our simulations show that high-affinity methanotrophy can be an important component of the net methane flux from arctic mineral soils. Simulations without this process overestimate methane emissions. Furthermore, simulations of methane flux seasonality are improved by dynamic simulation of active microbial biomass. Because a large fraction of the Arctic is characterized by mineral soils, high-affinity methanotrophy will likely have a strong effect on its net methane flux.

  13. Evolution of consumption distribution and model of wealth distribution in China between 1995 and 2012

    NASA Astrophysics Data System (ADS)

    Gao, Li

    2015-07-01

    We study the evolution of the distribution of consumption of individuals in the majority population in China during the period 1995-2012 and find that its probability density functions (PDFs) obey the rule Pc(x) = K(x - μ) e-(x - μ)2/2σ2. We also find (i) that the PDFs and the individual income distribution appear to be identical, (ii) that the peaks of the PDFs of the individual consumption distribution are consistently on the low side of the PDFs of the income distribution, and (iii) that the average of the marginal propensity to consume (MPC) is large, MPC bar = 0.77, indicating that in the majority population individual consumption is low and strongly dependent on income. The long right tail of the PDFs of consumption indicates that few people in China are participating in the high consumption economy, and that consumption inequality is high. After comparing the PDFs of consumption with the PDFs of income we obtain the PDFs of residual wealth during the period 1995-2012, which exhibit a Gaussian distribution. We use an agent-based kinetic wealth-exchange model (KWEM) to simulate this evolutional process and find that this Gaussian distribution indicates a strong propensity to save rather than spend. This may be due to an anticipation of such large potential outlays as housing, education, and health care in the context of an inadequate welfare support system.

  14. Input-Output Modeling for Urban Energy Consumption in Beijing: Dynamics and Comparison

    PubMed Central

    Zhang, Lixiao; Hu, Qiuhong; Zhang, Fan

    2014-01-01

    Input-output analysis has been proven to be a powerful instrument for estimating embodied (direct plus indirect) energy usage through economic sectors. Using 9 economic input-output tables of years 1987, 1990, 1992, 1995, 1997, 2000, 2002, 2005, and 2007, this paper analyzes energy flows for the entire city of Beijing and its 30 economic sectors, respectively. Results show that the embodied energy consumption of Beijing increased from 38.85 million tonnes of coal equivalent (Mtce) to 206.2 Mtce over the past twenty years of rapid urbanization; the share of indirect energy consumption in total energy consumption increased from 48% to 76%, suggesting the transition of Beijing from a production-based and manufacturing-dominated economy to a consumption-based and service-dominated economy. Real estate development has shown to be a major driving factor of the growth in indirect energy consumption. The boom and bust of construction activities have been strongly correlated with the increase and decrease of system-side indirect energy consumption. Traditional heavy industries remain the most energy-intensive sectors in the economy. However, the transportation and service sectors have contributed most to the rapid increase in overall energy consumption. The analyses in this paper demonstrate that a system-wide approach such as that based on input-output model can be a useful tool for robust energy policy making. PMID:24595199

  15. Identification of a nutrient-sensing transcriptional network in monocytes by using inbred rat models on a cafeteria diet

    PubMed Central

    Martínez-Micaelo, Neus; González-Abuín, Noemi; Terra, Ximena; Ardévol, Ana; Pinent, Montserrat; Petretto, Enrico; Blay, Mayte

    2016-01-01

    ABSTRACT Obesity has reached pandemic levels worldwide. The current models of diet-induced obesity in rodents use predominantly high-fat based diets that do not take into account the consumption of variety of highly palatable, energy-dense foods that are prevalent in Western society. We and others have shown that the cafeteria (CAF) diet is a robust and reproducible model of human metabolic syndrome with tissue inflammation in the rat. We have previously shown that inbred rat strains such as Wistar Kyoto (WKY) and Lewis (LEW) show different susceptibilities to CAF diets with distinct metabolic and morphometric profiles. Here, we show a difference in plasma MCP-1 levels and investigate the effect of the CAF diet on peripheral blood monocyte transcriptome, as powerful stress-sensing immune cells, in WKY and LEW rats. We found that 75.5% of the differentially expressed transcripts under the CAF diet were upregulated in WKY rats and were functionally related to the activation of the immune response. Using a gene co-expression network constructed from the genes differentially expressed between CAF diet-fed LEW and WKY rats, we identified acyl-CoA synthetase short-chain family member 2 (Acss2) as a hub gene for a nutrient-sensing cluster of transcripts in monocytes. The Acss2 genomic region is significantly enriched for previously established metabolism quantitative trait loci in the rat. Notably, monocyte expression levels of Acss2 significantly correlated with plasma glucose, triglyceride, leptin and non-esterified fatty acid (NEFA) levels as well as morphometric measurements such as body weight and the total fat following feeding with the CAF diet in the rat. These results show the importance of the genetic background in nutritional genomics and identify inbred rat strains as potential models for CAF-diet-induced obesity. PMID:27483348

  16. Factors Affecting Stream Nutrient Loads: A Synthesis of Regional SPARROW Model Results for the Continental United States1

    PubMed Central

    Preston, Stephen D; Alexander, Richard B; Schwarz, Gregory E; Crawford, Charles G

    2011-01-01

    Abstract We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models – 6 for total nitrogen and 6 for total phosphorus – all provide similar levels of prediction accuracy, but those for major river basins in the eastern half of the country were somewhat more accurate. The models simulate long-term mean annual stream nutrient loads as a function of a wide range of known sources and climatic (precipitation, temperature), landscape (e.g., soils, geology), and aquatic factors affecting nutrient fate and transport. The results confirm the dominant effects of urban and agricultural sources on stream nutrient loads nationally and regionally, but reveal considerable spatial variability in the specific types of sources that control water quality. These include regional differences in the relative importance of different types of urban (municipal and industrial point vs. diffuse urban runoff) and agriculture (crop cultivation vs. animal waste) sources, as well as the effects of atmospheric deposition, mining, and background (e.g., soil phosphorus) sources on stream nutrients. Overall, we found that the SPARROW model results provide a consistent set of information for identifying the major sources and environmental factors affecting nutrient fate and transport in United States watersheds at regional and subregional scales. PMID:22457574

  17. Factors affecting stream nutrient loads: A synthesis of regional SPARROW model results for the continental United States

    USGS Publications Warehouse

    Preston, Stephen D.; Alexander, Richard B.; Schwarz, Gregory E.; Crawford, Charles G.

    2011-01-01

    We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models - 6 for total nitrogen and 6 for total phosphorus - all provide similar levels of prediction accuracy, but those for major river basins in the eastern half of the country were somewhat more accurate. The models simulate long-term mean annual stream nutrient loads as a function of a wide range of known sources and climatic (precipitation, temperature), landscape (e.g., soils, geology), and aquatic factors affecting nutrient fate and transport. The results confirm the dominant effects of urban and agricultural sources on stream nutrient loads nationally and regionally, but reveal considerable spatial variability in the specific types of sources that control water quality. These include regional differences in the relative importance of different types of urban (municipal and industrial point vs. diffuse urban runoff) and agriculture (crop cultivation vs. animal waste) sources, as well as the effects of atmospheric deposition, mining, and background (e.g., soil phosphorus) sources on stream nutrients. Overall, we found that the SPARROW model results provide a consistent set of information for identifying the major sources and environmental factors affecting nutrient fate and transport in United States watersheds at regional and subregional scales. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  18. Evolutionary Tuning of Building Models to Monthly Electrical Consumption

    SciTech Connect

    Garrett, Aaron; New, Joshua Ryan; Chandler, Theodore

    2013-01-01

    Building energy models of existing buildings are unreliable unless calibrated so they correlate well with actual energy usage. Calibrating models is costly because it is currently an art which requires significant manual effort by an experienced and skilled professional. An automated methodology could significantly decrease this cost and facilitate greater adoption of energy simulation capabilities into the marketplace. The Autotune project is a novel methodology which leverages supercomputing, large databases of simulation data, and machine learning to allow automatic calibration of simulations to match measured experimental data on commodity hardware. This paper shares initial results from the automated methodology applied to the calibration of building energy models (BEM) for EnergyPlus (E+) to reproduce measured monthly electrical data.

  19. Incorporating Uncertainty Into the Ranking of SPARROW Model Nutrient Yields From Mississippi/Atchafalaya River Basin Watersheds1

    PubMed Central

    Robertson, Dale M; Schwarz, Gregory E; Saad, David A; Alexander, Richard B

    2009-01-01

    Excessive loads of nutrients transported by tributary rivers have been linked to hypoxia in the Gulf of Mexico. Management efforts to reduce the hypoxic zone in the Gulf of Mexico and improve the water quality of rivers and streams could benefit from targeting nutrient reductions toward watersheds with the highest nutrient yields delivered to sensitive downstream waters. One challenge is that most conventional watershed modeling approaches (e.g., mechanistic models) used in these management decisions do not consider uncertainties in the predictions of nutrient yields and their downstream delivery. The increasing use of parameter estimation procedures to statistically estimate model coefficients, however, allows uncertainties in these predictions to be reliably estimated. Here, we use a robust bootstrapping procedure applied to the results of a previous application of the hybrid statistical/mechanistic watershed model SPARROW (Spatially Referenced Regression On Watershed attributes) to develop a statistically reliable method for identifying “high priority” areas for management, based on a probabilistic ranking of delivered nutrient yields from watersheds throughout a basin. The method is designed to be used by managers to prioritize watersheds where additional stream monitoring and evaluations of nutrient-reduction strategies could be undertaken. Our ranking procedure incorporates information on the confidence intervals of model predictions and the corresponding watershed rankings of the delivered nutrient yields. From this quantified uncertainty, we estimate the probability that individual watersheds are among a collection of watersheds that have the highest delivered nutrient yields. We illustrate the application of the procedure to 818 eight-digit Hydrologic Unit Code watersheds in the Mississippi/Atchafalaya River basin by identifying 150 watersheds having the highest delivered nutrient yields to the Gulf of Mexico. Highest delivered yields were from

  20. Incorporating uncertainty into the ranking of SPARROW model nutrient yields from Mississippi/Atchafalaya River basin watersheds

    USGS Publications Warehouse

    Robertson, Dale M.; Schwarz, Gregory E.; Saad, David A.; Alexander, Richard B.

    2009-01-01

    Excessive loads of nutrients transported by tributary rivers have been linked to hypoxia in the Gulf of Mexico. Management efforts to reduce the hypoxic zone in the Gulf of Mexico and improve the water quality of rivers and streams could benefit from targeting nutrient reductions toward watersheds with the highest nutrient yields delivered to sensitive downstream waters. One challenge is that most conventional watershed modeling approaches (e.g., mechanistic models) used in these management decisions do not consider uncertainties in the predictions of nutrient yields and their downstream delivery. The increasing use of parameter estimation procedures to statistically estimate model coefficients, however, allows uncertainties in these predictions to be reliably estimated. Here, we use a robust bootstrapping procedure applied to the results of a previous application of the hybrid statistical/mechanistic watershed model SPARROW (Spatially Referenced Regression On Watershed attributes) to develop a statistically reliable method for identifying “high priority” areas for management, based on a probabilistic ranking of delivered nutrient yields from watersheds throughout a basin. The method is designed to be used by managers to prioritize watersheds where additional stream monitoring and evaluations of nutrient-reduction strategies could be undertaken. Our ranking procedure incorporates information on the confidence intervals of model predictions and the corresponding watershed rankings of the delivered nutrient yields. From this quantified uncertainty, we estimate the probability that individual watersheds are among a collection of watersheds that have the highest delivered nutrient yields. We illustrate the application of the procedure to 818 eight-digit Hydrologic Unit Code watersheds in the Mississippi/Atchafalaya River basin by identifying 150 watersheds having the highest delivered nutrient yields to the Gulf of Mexico. Highest delivered yields were from

  1. Fresh pear consumption is associated with better nutrient intake, diet quality, and weight parameters in adults: National Health and Nutrition Examination Survey 2001-2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    No studies have examined the association of consuming fresh pears on nutrient intake or adequacy, diet quality, and cardiovascular risk factors (CVRF). The purpose of this study was to examine these association in adults (n=24,808) participating the NHANES 2001-2010. Covariate adjusted linear regres...

  2. Quantifying Groundwater Nutrient Discharge to a Large Glacial Lake using a Watershed Loading Model

    NASA Astrophysics Data System (ADS)

    Schilling, K. E.

    2015-12-01

    Groundwater discharge to a lake is an important, if often neglected, component to water and nutrient budgets. Point measurements of groundwater discharge into a lake are prone to error, so in this study of 15.57 km2 West Lake Okoboji, Iowa, a watershed-based groundwater loading model was developed. Located in northwest Iowa, West Lake Okoboji is considered one of Iowa's premier tourist destinations but is threatened by eutrophication. A network of 21 observation wells was installed in the watershed to evaluate groundwater recharge and quality under representative land cover types in a range of landscape positions. Our objective was to develop typical groundwater responses from various land cover-landscape associations for scaling up to unmonitored areas in the watershed. Results indicated substantial variation in groundwater recharge and quality in the 3847 ha watershed. Recharge was similar among land covers under vegetation but was much lower under urban pavement. Nitrate-nitrogen concentrations were highest under cropped fields and lowest under perennial grassland and golf courses, whereas dissolved phosphorus was highest under residential and urban areas, including an engineered bioswale. A groundwater load allocation model indicated 91% of the nitrate load was from cropped areas and 7% from residential areas. In contrast, P loads were more equally divided among cropped fields (43%), perennial grass (36%) and residential (19%) areas. Based on the mass of nitrate and P in the lake, groundwater accounts for 71% and 18% of the nutrient inputs, respectively.

  3. Adolescents and Music Media: Toward an Involvement-Mediational Model of Consumption and Self-Concept

    ERIC Educational Resources Information Center

    Kistler, Michelle; Rodgers, Kathleen Boyce; Power, Thomas; Austin, Erica Weintraub; Hill, Laura Griner

    2010-01-01

    Using social cognitive theory and structural regression modeling, we examined pathways between early adolescents' music media consumption, involvement with music media, and 3 domains of self-concept (physical appearance, romantic appeal, and global self-worth; N=124). A mediational model was supported for 2 domains of self-concept. Music media…

  4. An Application of Variational Theory to an Integrated Walrasian Model of Exchange, Consumption and Production

    NASA Astrophysics Data System (ADS)

    Donato, M. B.; Milasi, M.; Vitanza, C.

    2010-09-01

    An existence result of a Walrasian equilibrium for an integrated model of exchange, consumption and production is obtained. The equilibrium model is characterized in terms of a suitable generalized quasi-variational inequality; so the existence result comes from an original technique which takes into account tools of convex and set-valued analysis.

  5. CO2 enrichment and N addition increase nutrient loss from decomposing leaf litter in subtropical model forest ecosystems

    NASA Astrophysics Data System (ADS)

    Liu, Juxiu; Fang, Xiong; Deng, Qi; Han, Tianfeng; Huang, Wenjuan; Li, Yiyong

    2015-01-01

    As atmospheric CO2 concentration increases, many experiments have been carried out to study effects of CO2 enrichment on litter decomposition and nutrient release. However, the result is still uncertain. Meanwhile, the impact of CO2 enrichment on nutrients other than N and P are far less studied. Using open-top chambers, we examined effects of elevated CO2 and N addition on leaf litter decomposition and nutrient release in subtropical model forest ecosystems. We found that both elevated CO2 and N addition increased nutrient (C, N, P, K, Ca, Mg and Zn) loss from the decomposing litter. The N, P, Ca and Zn loss was more than tripled in the chambers exposed to both elevated CO2 and N addition than those in the control chambers after 21 months of treatment. The stimulation of nutrient loss under elevated CO2 was associated with the increased soil moisture, the higher leaf litter quality and the greater soil acidity. Accelerated nutrient release under N addition was related to the higher leaf litter quality, the increased soil microbial biomass and the greater soil acidity. Our results imply that elevated CO2 and N addition will increase nutrient cycling in subtropical China under the future global change.

  6. CO2 enrichment and N addition increase nutrient loss from decomposing leaf litter in subtropical model forest ecosystems

    PubMed Central

    Liu, Juxiu; Fang, Xiong; Deng, Qi; Han, Tianfeng; Huang, Wenjuan; Li, Yiyong

    2015-01-01

    As atmospheric CO2 concentration increases, many experiments have been carried out to study effects of CO2 enrichment on litter decomposition and nutrient release. However, the result is still uncertain. Meanwhile, the impact of CO2 enrichment on nutrients other than N and P are far less studied. Using open-top chambers, we examined effects of elevated CO2 and N addition on leaf litter decomposition and nutrient release in subtropical model forest ecosystems. We found that both elevated CO2 and N addition increased nutrient (C, N, P, K, Ca, Mg and Zn) loss from the decomposing litter. The N, P, Ca and Zn loss was more than tripled in the chambers exposed to both elevated CO2 and N addition than those in the control chambers after 21 months of treatment. The stimulation of nutrient loss under elevated CO2 was associated with the increased soil moisture, the higher leaf litter quality and the greater soil acidity. Accelerated nutrient release under N addition was related to the higher leaf litter quality, the increased soil microbial biomass and the greater soil acidity. Our results imply that elevated CO2 and N addition will increase nutrient cycling in subtropical China under the future global change. PMID:25608664

  7. Annual nutrients export modelling by analysis of landuse and topographic information: case of a small Mediterranean catchment.

    PubMed

    Payraudeau, S; Tournoud, M G; Cernesson, F; Picot, B

    2001-01-01

    The preservation of water bodies from eutrophication implies accurate estimation of phosphorus and nitrogen loads and the control of nutrient production on a catchment scale. In this paper, a simple tool for the modelling of annual nutrient loads is presented. It is implemented in ARC/INFO GIS using Arc Macro Language (AML). The use of a GIS is justified as the spatial characteristics of the catchment area (land use, industrial wastewater location) dictate water quality. The annual nutrient loads are worked out on the catchment scale, using existing GIS routines together with specific routines developed in AML for hydrological and water quality modelling purposes. The catchment area is divided into hydrological subcatchments with relatively homogeneous spatial characteristics. Each subcatchment is linked to a specific nutrient export potential. These nutrient loads, calculated on a subcatchment-by-subcatchment basis, are conveyed to the outlet of the catchment and allow annual nutrient load estimation. A comparison with a water monitoring study is conducted to verify the adequation of modelling results for phosphorus and nitrogen loads.

  8. Annual nutrients export modelling by analysis of landuse and topographic information: case of a small Mediterranean catchment.

    PubMed

    Payraudeau, S; Tournoud, M G; Cernesson, F; Picot, B

    2001-01-01

    The preservation of water bodies from eutrophication implies accurate estimation of phosphorus and nitrogen loads and the control of nutrient production on a catchment scale. In this paper, a simple tool for the modelling of annual nutrient loads is presented. It is implemented in ARC/INFO GIS using Arc Macro Language (AML). The use of a GIS is justified as the spatial characteristics of the catchment area (land use, industrial wastewater location) dictate water quality. The annual nutrient loads are worked out on the catchment scale, using existing GIS routines together with specific routines developed in AML for hydrological and water quality modelling purposes. The catchment area is divided into hydrological subcatchments with relatively homogeneous spatial characteristics. Each subcatchment is linked to a specific nutrient export potential. These nutrient loads, calculated on a subcatchment-by-subcatchment basis, are conveyed to the outlet of the catchment and allow annual nutrient load estimation. A comparison with a water monitoring study is conducted to verify the adequation of modelling results for phosphorus and nitrogen loads. PMID:11548001

  9. Mathematical model of galactose regulation and metabolic consumption in yeast.

    PubMed

    Mitre, Tina M; Mackey, Michael C; Khadra, Anmar

    2016-10-21

    The galactose network has been extensively studied at the unicellular level to broaden our understanding of the regulatory mechanisms governing galactose metabolism in multicellular organisms. Although the key molecular players involved in the metabolic and regulatory processes of this system have been known for decades, their interactions and chemical kinetics remain incompletely understood. Mathematical models can provide an alternative method to study the dynamics of this network from a quantitative and a qualitative perspective. Here, we employ this approach to unravel the main properties of the galactose network, including equilibrium binary and temporal responses, as a way to decipher its adaptation to actively-changing inputs. We combine its two main components: the genetic branch, which allows for bistable responses, and a metabolic branch, encompassing the relevant metabolic processes that can be repressed by glucose. We use both computational tools to estimate model parameters based on published experimental data, as well as bifurcation analysis to decipher the properties of the system in various parameter regimes. Our model analysis reveals that the interplay between the inducer (galactose) and the repressor (glucose) creates a bistable regime which dictates the temporal responses of the system. Based on the same bifurcation techniques, we explain why the system is robust to genetic mutations and molecular instabilities. These findings may provide experimentalists with a theoretical framework with which they can determine how the galactose network functions under various conditions. PMID:27395401

  10. Modeling energy flow and nutrient cycling in natural semiarid grassland ecosystems with the aid of thematic mapper data

    NASA Technical Reports Server (NTRS)

    Lewis, James K.

    1987-01-01

    Energy flow and nutrient cycling were modeled as affected by herbivory on selected intensive sites along gradients of precipitation and soils, validating the model output by monitoring selected parameters with data derived from the Thematic Mapper (TM). Herbivore production was modeled along the gradient of soils and herbivory, and validated with data derived from TM in a spatial data base.

  11. Consumption of various forms of apples is associated with a better nutrient intake and improved nutrient adequacy in diets of children: National Health and Nutrition Examination Survey 2003-2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of fruit has been associated with a variety of health benefits, yet, 75% of children have usual intakes of total fruit below minimum recommended amounts. Apples are the second most commonly consumed fruit in the United States; however, no studies have examined the impact of apple consump...

  12. Estimating Summer Nutrient Concentrations in Northeastern Lakes from SPARROW Load Predictions and Modeled Lake Depth and Volume

    PubMed Central

    Milstead, W. Bryan; Hollister, Jeffrey W.; Moore, Richard B.; Walker, Henry A.

    2013-01-01

    Global nutrient cycles have been altered by the use of fossil fuels and fertilizers resulting in increases in nutrient loads to aquatic systems. In the United States, excess nutrients have been repeatedly reported as the primary cause of lake water quality impairments. Setting nutrient criteria that are protective of a lakes ecological condition is one common solution; however, the data required to do this are not always easily available. A useful solution for this is to combine available field data (i.e., The United States Environmental Protection Agency (USEPA) National Lake Assessment (NLA)) with average annual nutrient load models (i.e., USGS SPARROW model) to estimate summer concentrations across a large number of lakes. In this paper we use this combined approach and compare the observed total nitrogen (TN) and total phosphorus (TN) concentrations in Northeastern lakes from the 2007 National Lake Assessment to those predicted by the Northeast SPARROW model. We successfully adjusted the SPARROW predictions to the NLA observations with the use of Vollenweider equations, simple input-output models that predict nutrient concentrations in lakes based on nutrient loads and hydraulic residence time. This allows us to better predict summer concentrations of TN and TP in Northeastern lakes and ponds. On average we improved our predicted concentrations of TN and TP with Vollenweider models by 18.7% for nitrogen and 19.0% for phosphorus. These improved predictions are being used in other studies to model ecosystem services (e.g., aesthetics) and dis-services (e.g. cyanobacterial blooms) for ~18,000 lakes in the Northeastern United States. PMID:24260579

  13. Estimating summer nutrient concentrations in Northeastern lakes from SPARROW load predictions and modeled lake depth and volume.

    PubMed

    Milstead, W Bryan; Hollister, Jeffrey W; Moore, Richard B; Walker, Henry A

    2013-01-01

    Global nutrient cycles have been altered by the use of fossil fuels and fertilizers resulting in increases in nutrient loads to aquatic systems. In the United States, excess nutrients have been repeatedly reported as the primary cause of lake water quality impairments. Setting nutrient criteria that are protective of a lakes ecological condition is one common solution; however, the data required to do this are not always easily available. A useful solution for this is to combine available field data (i.e., The United States Environmental Protection Agency (USEPA) National Lake Assessment (NLA)) with average annual nutrient load models (i.e., USGS SPARROW model) to estimate summer concentrations across a large number of lakes. In this paper we use this combined approach and compare the observed total nitrogen (TN) and total phosphorus (TN) concentrations in Northeastern lakes from the 2007 National Lake Assessment to those predicted by the Northeast SPARROW model. We successfully adjusted the SPARROW predictions to the NLA observations with the use of Vollenweider equations, simple input-output models that predict nutrient concentrations in lakes based on nutrient loads and hydraulic residence time. This allows us to better predict summer concentrations of TN and TP in Northeastern lakes and ponds. On average we improved our predicted concentrations of TN and TP with Vollenweider models by 18.7% for nitrogen and 19.0% for phosphorus. These improved predictions are being used in other studies to model ecosystem services (e.g., aesthetics) and dis-services (e.g. cyanobacterial blooms) for ~18,000 lakes in the Northeastern United States. PMID:24260579

  14. Multiple soil nutrient competition between plants, microbes, and mineral surfaces: model development, parameterization, and example applications in several tropical forests

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Riley, W. J.; Tang, J.; Koven, C. D.

    2015-03-01

    Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate, and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3-, and POx (representing the sum of PO43-, HPO42-, and H2PO4-)) and five potential competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers, and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus, and free NH4+ at a tropical forest site (Tapajos). The overall model posterior uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer-substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results imply that the competitiveness (from most to least competitive) followed this order: (1) for NH4+, nitrifiers ~ decomposing microbes > plant roots, (2) for NO3-, denitrifiers ~ decomposing microbes > plant roots, (3) for POx, mineral surfaces > decomposing microbes ~ plant roots. Although smaller, plant relative competitiveness is of the same order of magnitude as microbes. We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii

  15. Impact of proliferation strategies on food web viability in a model with closed nutrient cycle

    NASA Astrophysics Data System (ADS)

    Szwabiński, Janusz

    2012-11-01

    A food web model with a closed nutrient cycle is presented and analyzed via Monte Carlo simulations. The model consists of three trophic levels, each of which is populated by animals of one distinct species. While the species at the intermediate level feeds on the basal species, and is eaten by the predators living at the highest level, the basal species itself uses the detritus of animals from higher levels as the food resource. The individual organisms remain localized, but the species can invade new lattice areas via proliferation. The impact of different proliferation strategies on the viability of the system is investigated. From the phase diagrams generated in the simulations it follows that in general a strategy with the intermediate level species searching for food is the best for the survival of the system. The results indicate that both the intermediate and top level species play a critical role in maintaining the structure of the system.

  16. Stochastic Sensitivity Analysis for a Competitive Turbidostat Model with Inhibitory Nutrients

    NASA Astrophysics Data System (ADS)

    Xu, Chaoqun; Yuan, Sanling; Zhang, Tonghua

    A stochastic model of turbidostat in which two microorganism species compete for an inhibitory growth-limiting nutrient is considered. In the deterministic case, the model has rich dynamics: a coexistence equilibrium and the washout equilibrium can be simultaneously stable, and a stable limit cycle may exist. In the stochastic case, a phenomenon of noise-induced extinction occurs. Namely, the stochastic trajectory near the deterministic coexistence equilibrium will tend to the washout equilibrium. Based on the stochastic sensitivity function technique, in this paper, we construct the confidence ellipse and then estimate the critical value of the intensity for noise generating a transition from coexistence to extinction. We also construct the confidence band to find the configurational arrangement of the stochastic cycle.

  17. Global solutions to a chemotaxis model with consumption of chemoattractant

    NASA Astrophysics Data System (ADS)

    Wang, Liangchen; Mu, Chunlai; Hu, Xuegang

    2016-08-01

    This paper is devoted to the following chemotaxis system u_t=nabla\\cdot(D(u)nabla u)-nabla\\cdot(S(u)nabla v),quad &xin Ω,quad t>0, v_t=Δ v-uv,quad &xinΩ,quad t>0, under homogeneous Neumann boundary conditions in a smooth bounded domain {Ωsubset {R}^n} ({n≥2}), not necessarily being convex. There are some constants {c_D > 0}, {c_S > 0}, {min{R}} and {qin{R}} such that D(u) ≥ c_D(u+1)^{m-1} quad{and} quad S(u)≤ c_S(u+1)^{q-1}quad for all u≥0. If {q < m+n+2/2n}, it is shown that the model possesses a unique global classical solution which is uniformly bounded; if {q < m/2+n+2/2n}, the global existence of solution is established.

  18. Application of the SPARROW model to assess surface-water nutrient conditions and sources in the United States Pacific Northwest

    USGS Publications Warehouse

    Wise, Daniel R.; Johnson, Henry M.

    2013-01-01

    The watershed model SPARROW (Spatially Referenced Regressions on Watershed attributes) was used to estimate mean annual surface-water nutrient conditions (total nitrogen and total phosphorus) and to identify important nutrient sources in catchments of the Pacific Northwest region of the United States for 2002. Model-estimated nutrient yields were generally higher in catchments on the wetter, western side of the Cascade Range than in catchments on the drier, eastern side. The largest source of locally generated total nitrogen stream load in most catchments was runoff from forestland, whereas the largest source of locally generated total phosphorus stream load in most catchments was either geologic material or livestock manure (primarily from grazing livestock). However, the highest total nitrogen and total phosphorus yields were predicted in the relatively small number of catchments where urban sources were the largest contributor to local stream load. Two examples are presented that show how SPARROW results can be applied to large rivers—the relative contribution of different nutrient sources to the total nitrogen load in the Willamette River and the total phosphorus load in the Snake River. The results from this study provided an understanding of the regional patterns in surface-water nutrient conditions and should be useful to researchers and water-quality managers performing local nutrient assessments.

  19. Cooked oatmeal consumption is associated with better diet quality, better nutrient intakes, and reduced risk for central adiposity and obesity in children 2–18 years: NHANES 2001–2010

    PubMed Central

    O'Neil, Carol E.; Nicklas, Theresa A.; Fulgoni, Victor L.; DiRienzo, Maureen A.

    2015-01-01

    Background None of the studies of whole grains that have looked either at diet or weight/adiposity measures have focused exclusively on oatmeal. Objective The objective of this study was to assess the association between oatmeal consumption and nutrient intake, diet quality, and weight/adiposity of children aged 2–18. Design A nationally representative sample of children aged 2–18 (N=14,690) participating in National Health and Nutrition Examination Survey 2001–2010 was used. Intake was determined from a single 24-h dietary recall. Diet quality was measured using the Healthy Eating Index-2010 (HEI-2010). Covariate-adjusted regression analyses, using appropriate sample weights, were used to determine differences between oatmeal consumers and non-consumers for demographics, nutrient intakes, diet quality, and weight/adiposity measures (p<0.01). Logistic regression was performed to calculate odds ratios for weight measures and obesity (p<0.05). Results Compared to non-consumers, oatmeal consumers were more likely to be younger and less likely to be smokers. Consumers had higher intakes of dietary fiber, vitamin A, thiamin, riboflavin, calcium, phosphorus, magnesium, iron, copper, and potassium, and significantly lower intakes of total, monounsaturated and saturated fatty acids, cholesterol, and sodium. Oatmeal consumers had higher dietary quality scores attributable to higher intakes of whole grains and lower intakes of refined grains and empty calories. Children consuming oatmeal were at lower risk for having central adiposity and being obese. Conclusions Consumption of oatmeal by children was associated with better nutrient intake, diet quality, and reduced risk for central adiposity and obesity and should be encouraged as part of an overall healthful diet. PMID:26022379

  20. Econometric model of gasoline consumption, vehicle miles traveled, and new car purchases

    SciTech Connect

    Springer, R.K.; Resek, R.W.

    1981-01-01

    Continuing concern over fuel shortages and emphasis on smaller, more-efficient automobiles have led to studies relating automobile usage to gasoline consumption. This paper provides meaningful aggregates for automobile characteristics and emphasizes five different classes of cars in the estimation, using a time series of cross-sectional data. The effects of changing patterns in automobile ownership on total vehicle miles traveled and on gasoline consumption are modeled explicitly. In estimating equations for new-car demand, not only economic variables such as income and automobile price are considered but also the effects of changing gasoline prices and vehicle miles traveled. This analysis also enables one to trace the behavior of consumers' preferences for changes in the size of new cars. An important link in the model relates the vehicle miles and gasoline-consumption variables, and specific interest is given to gasoline price elasticities. 15 references.

  1. A Coupled Ocean General Circulation, Biogeochemical, and Radiative Model of the Global Oceans: Seasonal Distributions of Ocean Chlorophyll and Nutrients

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Busalacchi, Antonio (Technical Monitor)

    2000-01-01

    A coupled ocean general circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability. and the interactions among three functional phytoplankton groups (diatoms. chlorophytes, and picoplankton) and three nutrients (nitrate, ammonium, and silicate). Basin scale (greater than 1000 km) model chlorophyll results are in overall agreement with CZCS pigments in many global regions. Seasonal variability observed in the CZCS is also represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are generally in conformance although occasional departures are apparent. Model nitrate distributions agree with in situ data, including seasonal dynamics, except for the equatorial Atlantic. The overall agreement of the model with satellite and in situ data sources indicates that the model dynamics offer a reasonably realistic simulation of phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent many aspects of the great diversity of physical, biological, chemical, and radiative environments encountered in the global oceans.

  2. Improvement in fruit and vegetable consumption associated with more favorable energy density and nutrient and food group intake, but not kilocalories

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Children generally do not consume adequate amounts of fruits and vegetables (F/V). Eating more F/V can improve energy density and overall diet quality. Our aim was to investigate whether improvements in F/V consumption were associated with improvements in energy density, total calories, and dietary ...

  3. Modeling of rotary cement kilns: Applications to reduction in energy consumption

    SciTech Connect

    Mujumdar, K.S.; Arora, A.; Ranade, V.V.

    2006-03-29

    We discuss and evaluate possible ways of reducing energy consumption in rotary cement kilns. A comprehensive one-dimensional model was developed to simulate complex processes occurring in rotary cement kilns. A modeling strategy comprising three submodels, viz. a model for simulating the variation of bed height in the kiln, a model for simulating reactions and heat transfer in the bed region, and a model for simulating coal combustion and heat transfer in the freeboard region, was developed. Melting and formation of coating within the kiln were accounted for. Combustion of coal in the freeboard region was modeled by accounting for devolatilization, finite-rate gas-phase combustion, and char reaction. The simulated results were validated with the available data from three industrial kilns. The model was then used to understand the influence of various design and operating parameters on kiln performance. Several ways of reducing energy consumption in kilns were then computationally investigated. The model was also used to propose and to evaluate a practical solution of using a secondary shell to reduce energy consumption in rotary cement kilns. Simulation results indicate that varying kiln operating variables, viz. solid flow rate or RPM, can result only in small changes in kiln energetics. Use of a secondary shell over the kiln and energy recovery by passing air through the annular gap between the two appears to be a promising way to achieve significant energy savings. The developed model and the presented results will be useful for enhancing the performance of rotary cement kilns.

  4. A stoichiometric producer-grazer model incorporating the effects of excess food-nutrient content on consumer dynamics.

    PubMed

    Peace, Angela; Zhao, Yuqin; Loladze, Irakli; Elser, James J; Kuang, Yang

    2013-08-01

    There has been important progress in understanding ecological dynamics through the development of the theory of ecological stoichiometry. For example, modeling under this framework allows food quality to affect consumer dynamics. While the effects of nutrient deficiency on consumer growth are well understood, recent discoveries in ecological stoichiometry suggest that consumer dynamics are not only affected by insufficient food nutrient content (low phosphorus (P): carbon (C) ratio) but also by excess food nutrient content (high P:C). This phenomenon is known as the stoichiometric knife edge, in which animal growth is reduced not only by food with low P content but also by food with high P content, and needs to be incorporated into mathematical models. Here we present a Lotka-Volterra type model to investigate the growth response of Daphnia to algae of varying P:C ratios capturing the mechanism of the stoichiometric knife edge.

  5. Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

    NASA Astrophysics Data System (ADS)

    Bouwman, A. F.; Bierkens, M. F. P.; Griffioen, J.; Hefting, M. M.; Middelburg, J. J.; Middelkoop, H.; Slomp, C. P.

    2013-01-01

    In river basins, soils, groundwater, riparian zones and floodplains, streams, rivers, lakes and reservoirs act as successive filters in which the hydrology, ecology and biogeochemical processing are strongly coupled and together act to retain a significant fraction of the nutrients transported. This paper compares existing river ecology concepts with current approaches to describe river biogeochemistry, and assesses the value of these concepts and approaches for understanding the impacts of interacting global change disturbances on river biogeochemistry. Through merging perspectives, concepts, and modeling techniques, we propose integrated model approaches that encompass both aquatic and terrestrial components in heterogeneous landscapes. In this model framework, existing ecological and biogeochemical concepts are extended with a balanced approach for assessing nutrient and sediment delivery, on the one hand, and nutrient in-stream retention on the other hand.

  6. Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

    NASA Astrophysics Data System (ADS)

    Bouwman, A. F.; Bierkens, M. F. P.; Griffioen, J.; Hefting, M. M.; Middelburg, J. J.; Middelkoop, H.; Slomp, C. P.

    2012-07-01

    In river basins, soils, groundwater, riparian zones, streams, rivers, lakes and reservoirs act as successive filters in which the hydrology, ecology and biogeochemical processing are strongly coupled and together act to retain a significant fraction of the nutrients transported. This paper compares existing river ecology concepts with current approaches to describe river biogeochemistry, and assesses the value of these concepts and approaches for understanding the impacts of interacting global change disturbances on river biogeochemistry. Through merging perspectives, concepts, modeling techniques, we propose integrated model approaches that encompass both aquatic and terrestrial components in heterogeneous landscapes. In this model framework, existing ecological and biogeochemistry concepts are extended with a balanced approach for assessing nutrient and sediment delivery on the one hand, and nutrient in-stream retention on the other hand.

  7. MODELING NITROGEN-CARBON CYCLING AND OXYGEN CONSUMPTION IN BOTTOM SEDIMENTS

    EPA Science Inventory

    A model framework is presented for simulating nitrogen and carbon cycling at the sediment–water interface, and predicting oxygen consumption by oxidation reactions inside the sediments. Based on conservation of mass and invoking simplifying assumptions, a coupled system of diffus...

  8. In Vitro and In Vivo Models of Staphylococcus aureus Endophthalmitis Implicate Specific Nutrients in Ocular Infection

    PubMed Central

    Sadaka, Ama; Palmer, Kelli; Suzuki, Takashi; Gilmore, Michael S.

    2014-01-01

    Purpose To define global transcriptional responses of Staphylococcus aureus and its codY mutant (CodY is a transcription regulator of virulence and metabolic genes in response to branched-chain amino acids) when growing in bovine aqueous (AH) and vitreous humor (VH) in vitro, and to investigate the impact of codY deletion on S. aureus virulence in a novel murine anterior chamber (AC) infection model. Methods For the in vitro model, differential transcriptomic gene expression of S. aureus and its codY mutant grown in chemically defined medium (CDM), AH, and VH was analyzed. Furthermore, the strains were inoculated into the AC of mice. Changes in bacterial growth, electroretinography and inflammation scores were monitored. Results Bovine AH and VH provide sufficient nutrition for S. aureus growth in vitro. Transcriptome analysis identified 72 unique open reading frames differentially regulated ≥10-fold between CDM, AH, and VH. In the AC model, we found comparable growth of the codY mutant and wild type strains in vivo. Average inflammation scores and retinal function were significantly worse for codY mutant-infected eyes at 24 h post-infection. Conclusion Our in vitro bovine AH and VH models identified likely nutrient sources for S. aureus in the ocular milieu. The in vivo model suggests that control of branched-chain amino acid availability has therapeutic potential in limiting S. aureus endophthalmitis severity. PMID:25340474

  9. Modelling the eutrophication of the Seine Bight (France) under historical, present and future riverine nutrient loading

    NASA Astrophysics Data System (ADS)

    Cugier, P.; Billen, G.; Guillaud, J. F.; Garnier, J.; Ménesguen, A.

    2005-03-01

    Because of the occurrence of episodic blooms of toxic dinoflagellates, eutrophication of the Seine Bight is a subject of growing concern. In order to better understand the relationships between these processes and human activity in the Seine watershed, two models have been used in connection: A model describing nutrient (N, P, Si) transfer processes at the scale of the whole Seine Basin (RIVERSTRAHLER [Billen, G., Garnier, J., Ficht, A., Cun, C., 2001. Modelling the response of water quality in the Seine River Estuary in response to human activity in the watershed over the last 50 years. Estuaries 24, 977-993]), allowing human activity (agricultural practices, waterscape management, urban wastewater management, etc.) to be related to fluxes delivered to the sea. A model of 3D hydrodynamic and ecological model of the Seine Bight (SiAM-3D/ELISE [Cugier, P., 1999. Modélisation du devenir à moyen terme dans l'eau et le sédiment des éléments majeurs (N, P, Si, O) rejetés par la Seine en baie de Seine. Thèse de doctorat, Univ. de Caen, p. 241; Cugier, P., Le Hir, P., 2000. Modélisation 3D des matières en suspension en baie de Seine Orientale (Manche, France). C. R. Acad. Sci. Paris, Sciences de la Terre et des planétes 331, 287-294]), capable of reproducing the spatio-temporal variations of sediment transport, thermo-haline stratification and phytoplanktonic development in the plume of the Seine river. The models are validated by their ability to reproduce observed trends of interannual variations of nutrients delivered by the Seine during the last 50 years, as well as the response of the marine system in terms of diatoms and dinoflagellate development, for which data are available from 1976 to 1984 for the former and from 1987 to 1997 for the latter. The results show clearly that dry years, where silica inputs show a deficit with respect to nitrogen and phosphorus, are those where summer blooms of dinoflagellates are particularly pronounced. Various scenarios

  10. Data-driven behavioural modelling of residential water consumption to inform water demand management strategies

    NASA Astrophysics Data System (ADS)

    Giuliani, Matteo; Cominola, Andrea; Alshaf, Ahmad; Castelletti, Andrea; Anda, Martin

    2016-04-01

    The continuous expansion of urban areas worldwide is expected to highly increase residential water demand over the next few years, ultimately challenging the distribution and supply of drinking water. Several studies have recently demonstrated that actions focused only on the water supply side of the problem (e.g., augmenting existing water supply infrastructure) will likely fail to meet future demands, thus calling for the concurrent deployment of effective water demand management strategies (WDMS) to pursue water savings and conservation. However, to be effective WDMS do require a substantial understanding of water consumers' behaviors and consumption patterns at different spatial and temporal resolutions. Retrieving information on users' behaviors, as well as their explanatory and/or causal factors, is key to spot potential areas for targeting water saving efforts and to design user-tailored WDMS, such as education campaigns and personalized recommendations. In this work, we contribute a data-driven approach to identify household water users' consumption behavioural profiles and model their water use habits. State-of-the-art clustering methods are coupled with big data machine learning techniques with the aim of extracting dominant behaviors from a set of water consumption data collected at the household scale. This allows identifying heterogeneous groups of consumers from the studied sample and characterizing them with respect to several consumption features. Our approach is validated onto a real-world household water consumption dataset associated with a variety of demographic and psychographic user data and household attributes, collected in nine towns of the Pilbara and Kimberley Regions of Western Australia. Results show the effectiveness of the proposed method in capturing the influence of candidate determinants on residential water consumption profiles and in attaining sufficiently accurate predictions of users' consumption behaviors, ultimately providing

  11. Modelling water discharges and nutrient inputs into a Mediterranean lagoon (Thau, France). Impact on phytoplankton production.

    NASA Astrophysics Data System (ADS)

    Plus, M.; La Jeunesse, I.; Bouraoui, F.

    2003-04-01

    The lagoon of Thau (French Mediterranean coast), is a large (75 km2) and rather deep coastal lagoon (mean depth 4 m), connected to the sea by its two extremities (residence time: about 3 months). Besides its ecological interest as a breeding and transit zone for some sea fish species, the lagoon has a notable economic importance due to shellfish cultivation with an annual oyster production of about 15 000 tons. This considerable production depends to a large extent on nutrient inputs into the ecosystem, supplied mainly from fresh water. The catchment area is about 280 Km2, including agriculture (mainly vineyards), industrial activities and urban waste. Due to the low water renewal and to the intensive shellfish farming activities the Thau lagoon is particularly sensitive to any modification in watershed outputs. The aim of this study is to assess the impact of watershed outputs on the lagoon ecosystem. The Soil and Water Assessment Tool (SWAT model) has been applied to the Thau lagoon catchment area in order to simulate water discharges and nutrients (ammonium, nitrate, and phosphates) inputs into the lagoon on a 10 years period (1989-1999). The model has been calibrated and validated using measured data available for the two main rivers of the watershed, representing about 50% of total freshwater inputs. The model predictions compared favourably with the measurements concerning water quantity as well as major water quality determinants (ammonium, nitrate, phosphates, and suspended matter). Then, several scenarios (e. g. changes in agricultural practices) have been run and the simulated results were used as forcing variables in a lagoon ecosystem model, previously developed for Thau. The latter is a three-dimensional model coupling both hydrodynamical and biological processes. The following state variables are simulated in the model biological part: ammonia, nitrates, phytoplankton, zooplankton, detritus, oyster biodeposits and oxygen. In addition to the inputs

  12. Modeling energy consumption in membrane bioreactors for wastewater treatment in north Africa.

    PubMed

    Skouterisl, George; Arnot, Tom C; Jraou, Mouna; Feki, Firas; Sayadi, Sami

    2014-03-01

    Two pilot-scale membrane bioreactors were operated alongside a full-sized activated sludge plant in Tunisia in order to compare specific energy demand and treated water quality. Energy consumption rates were measured for the complete membrane bioreactor systems and for their different components. Specific energy demand was measured for the systems and compared with the activated sludge plant, which operated at around 3 kWh m(-3). A model was developed for each membrane bioreactor based on both dynamic and steady-state mass balances, microbial kinetics and stoichiometry, and energy balance. Energy consumption was evaluated as a function of mixed-liquor suspended solids concentration, net permeate fluxes, and the resultant treated water quality. This work demonstrates the potential for using membrane bioreactors in decentralised domestic water treatment in North Africa, at energy consumption levels similar or lower than conventional activated sludge systems, with the added benefit of producing treated water suitable for unrestricted crop irrigation.

  13. A distributed multi-compartment hydrological model with dynamic vegetation and nutrient turnover

    NASA Astrophysics Data System (ADS)

    Delfs, Jens-Olaf; Gayler, Sebastian; Streck, Thilo; Selle, Benny; Klein, Christian; Priesack, Eckart; Singh, Ashok; Kalbacher, Thomas; Wang, Wenqing; Kolditz, Olaf

    2013-04-01

    Agricultural practices impact soils and the wider environment (groundwater, receiving water courses and ponds, etc.) with various feedback loops. For instance, groundwater extraction may increase infiltration rates and nitrate leaching from the plant root zone. To assess such inter-compartment feedbacks with a numerical model, the object-oriented modeling platform OpenGeoSys (OGS), which is designed for Thermo-Hydro-Mechanical-Chemical processes in porous and fractured media (open to the public via www.opengeosys.org), is coupled with the soil-plant-atmosphere model system Expert-N. Latter consists of interchangeable sub-modules for thermo-hydro-chemical processes at land surfaces subject to agricultural production and forestry. In the resulting model, OGS solves partial differential equations through a Galerkin finite element approach to transfer water, air, heat and nitrogen compounds in the overland, soil and aquifer compartments, while Expert-N provides source / sink terms for evapotranspiration, plant growth, and nutrient turnover (mineralization, denitrification, etc.). General criteria are determined to guarantee stability when coupling hydrological compartments by iterating and to ensure that inter-compartment water and solute fluxes are insensitive to variations in leakage. Test cases include a synthetic surface-subsurface flow benchmark with evapotranspiration (Panday & Huyakorn problem) and a cross section of the Ammer catchment in South-West Germany, where precipitation water flows to groundwater wells, which are used for the supply of potable water.

  14. Modeling controlled nutrient release from polymer coated fertilizers: diffusion release from single granules.

    PubMed

    Shaviv, Avi; Raban, Smadar; Zaidel, Elina

    2003-05-15

    A comprehensive model describing the complex and "non-Fickian" (mathematically nonlinear) nature of the release from single granules of membrane coated, controlled release fertilizers (CRFs) is proposed consisting of three stages: i. a lag period during which water penetrates the coating of the granule dissolving part of the solid fertilizer in it ii. a period of linear release during which water penetration into and release out occur concomitantly while the total volume of the granules remains practically constant; and iii. a period of "decaying release", starting as the concentration inside the granule starts to decrease. A mathematical model was developed based on vapor and nutrient diffusion equations. The model predicts the release stages in terms of measurable geometrical and chemophysical parameters such as the following: the product of granule radius and coating thickness, water and solute permeability, saturation concentration of the fertilizer, and its density. The model successfully predicts the complex and "sigmoidal" pattern of release that is essential for matching plant temporal demand to ensure high agronomic and environmental effectiveness. It also lends itself to more complex statistical formulations which account for the large variability within large populations of coated CRFs and can serve for further improving CRF production and performance. PMID:12785532

  15. Modeling controlled nutrient release from polymer coated fertilizers: diffusion release from single granules.

    PubMed

    Shaviv, Avi; Raban, Smadar; Zaidel, Elina

    2003-05-15

    A comprehensive model describing the complex and "non-Fickian" (mathematically nonlinear) nature of the release from single granules of membrane coated, controlled release fertilizers (CRFs) is proposed consisting of three stages: i. a lag period during which water penetrates the coating of the granule dissolving part of the solid fertilizer in it ii. a period of linear release during which water penetration into and release out occur concomitantly while the total volume of the granules remains practically constant; and iii. a period of "decaying release", starting as the concentration inside the granule starts to decrease. A mathematical model was developed based on vapor and nutrient diffusion equations. The model predicts the release stages in terms of measurable geometrical and chemophysical parameters such as the following: the product of granule radius and coating thickness, water and solute permeability, saturation concentration of the fertilizer, and its density. The model successfully predicts the complex and "sigmoidal" pattern of release that is essential for matching plant temporal demand to ensure high agronomic and environmental effectiveness. It also lends itself to more complex statistical formulations which account for the large variability within large populations of coated CRFs and can serve for further improving CRF production and performance.

  16. Effect of the consumption of high energy dense and fortified gruels on energy and nutrient intakes of 6-10-month-old Vietnamese infants.

    PubMed

    Van Hoan, Nguyen; Van Phu, Pham; Salvignol, Bertrand; Berger, Jacques; Trèche, Serge

    2009-10-01

    The aim of this study was to test the ability of two new products, an instant infant flour and a food supplement containing amylases, to increase energy and micronutrient intakes of infants older than 6 months. Three groups of 48 infants were randomly constituted. Infants in groups 1 and 2 consumed at least twice a day gruel made either from the instant flour or from the food supplement. Infants from the control group received complementary foods prepared in the usual way. Each infant was surveyed during a whole day in order to measure feeding frequencies and characteristics as well as amounts of the different types of complementary foods consumed. Foods consumed by infants in the two experimental groups differed considerably in energy, micronutrient density and in consistency from the home-made complementary foods. Due to the incorporation of amylases, gruels made from the food supplement had a higher energy density, a more appropriate consistency and resulted in higher intakes per meal than gruels made from instant flour. In comparison with home-made complementary foods, both experimental products resulted in significantly higher energy and nutrient intakes. The two experimental products appeared to increase sufficiently both energy and nutrient intakes of infants to complement their breastmilk intake.

  17. SPARROW models used to understand nutrient sources in the Mississippi/Atchafalaya River Basin

    USGS Publications Warehouse

    Robertson, Dale M.; Saad, David A.

    2013-01-01

    Nitrogen (N) and phosphorus (P) loading from the Mississippi/Atchafalaya River Basin (MARB) has been linked to hypoxia in the Gulf of Mexico. To describe where and from what sources those loads originate, SPAtially Referenced Regression On Watershed attributes (SPARROW) models were constructed for the MARB using geospatial datasets for 2002, including inputs from wastewater treatment plants (WWTPs), and calibration sites throughout the MARB. Previous studies found that highest N and P yields were from the north-central part of the MARB (Corn Belt). Based on the MARB SPARROW models, highest N yields were still from the Corn Belt but centered over Iowa and Indiana, and highest P yields were widely distributed throughout the center of the MARB. Similar to that found in other studies, agricultural inputs were found to be the largest N and P sources throughout most of the MARB: farm fertilizers were the largest N source, whereas farm fertilizers, manure, and urban inputs were dominant P sources. The MARB models enable individual N and P sources to be defined at scales ranging from SPARROW catchments (∼50 km2) to the entire area of the MARB. Inputs of P from WWTPs and urban areas were more important than found in most other studies. Information from this study will help to reduce nutrient loading from the MARB by providing managers with a description of where each of the sources of N and P are most important, thus providing a basis for prioritizing management actions and ultimately reducing the extent of Gulf hypoxia.

  18. SPARROW Models Used to Understand Nutrient Sources in the Mississippi/Atchafalaya River Basin.

    PubMed

    Robertson, Dale M; Saad, David A

    2013-09-01

    Nitrogen (N) and phosphorus (P) loading from the Mississippi/Atchafalaya River Basin (MARB) has been linked to hypoxia in the Gulf of Mexico. To describe where and from what sources those loads originate, SPAtially Referenced Regression On Watershed attributes (SPARROW) models were constructed for the MARB using geospatial datasets for 2002, including inputs from wastewater treatment plants (WWTPs), and calibration sites throughout the MARB. Previous studies found that highest N and P yields were from the north-central part of the MARB (Corn Belt). Based on the MARB SPARROW models, highest N yields were still from the Corn Belt but centered over Iowa and Indiana, and highest P yields were widely distributed throughout the center of the MARB. Similar to that found in other studies, agricultural inputs were found to be the largest N and P sources throughout most of the MARB: farm fertilizers were the largest N source, whereas farm fertilizers, manure, and urban inputs were dominant P sources. The MARB models enable individual N and P sources to be defined at scales ranging from SPARROW catchments (∼50 km) to the entire area of the MARB. Inputs of P from WWTPs and urban areas were more important than found in most other studies. Information from this study will help to reduce nutrient loading from the MARB by providing managers with a description of where each of the sources of N and P are most important, thus providing a basis for prioritizing management actions and ultimately reducing the extent of Gulf hypoxia.

  19. Improving consumption rate estimates by incorporating wild activity into a bioenergetics model.

    PubMed

    Brodie, Stephanie; Taylor, Matthew D; Smith, James A; Suthers, Iain M; Gray, Charles A; Payne, Nicholas L

    2016-04-01

    Consumption is the basis of metabolic and trophic ecology and is used to assess an animal's trophic impact. The contribution of activity to an animal's energy budget is an important parameter when estimating consumption, yet activity is usually measured in captive animals. Developments in telemetry have allowed the energetic costs of activity to be measured for wild animals; however, wild activity is seldom incorporated into estimates of consumption rates. We calculated the consumption rate of a free-ranging marine predator (yellowtail kingfish, Seriola lalandi) by integrating the energetic cost of free-ranging activity into a bioenergetics model. Accelerometry transmitters were used in conjunction with laboratory respirometry trials to estimate kingfish active metabolic rate in the wild. These field-derived consumption rate estimates were compared with those estimated by two traditional bioenergetics methods. The first method derived routine swimming speed from fish morphology as an index of activity (a "morphometric" method), and the second considered activity as a fixed proportion of standard metabolic rate (a "physiological" method). The mean consumption rate for free-ranging kingfish measured by accelerometry was 152 J·g(-1)·day(-1), which lay between the estimates from the morphometric method (μ = 134 J·g(-1)·day(-1)) and the physiological method (μ = 181 J·g(-1)·day(-1)). Incorporating field-derived activity values resulted in the smallest variance in log-normally distributed consumption rates (σ = 0.31), compared with the morphometric (σ = 0.57) and physiological (σ = 0.78) methods. Incorporating field-derived activity into bioenergetics models probably provided more realistic estimates of consumption rate compared with the traditional methods, which may further our understanding of trophic interactions that underpin ecosystem-based fisheries management. The general methods used to estimate active metabolic rates of free-ranging fish

  20. ‘Wired’, yet intoxicated: Modeling binge caffeine and alcohol co-consumption in the mouse

    PubMed Central

    Fritz, Brandon M.; Companion, Michel; Boehm, Stephen L.

    2014-01-01

    Background The combination of highly caffeinated ‘energy drinks’ with alcohol (ethanol) has become popular among young adults and intoxication via such beverages has been associated with an elevated risk for harmful behaviors. However, there are discrepancies in the human literature regarding the effect of caffeine on alcohol intoxication, perhaps due to confounding factors such as personality type, expectancy, and history of exposure. Animal models of co-exposure are resistant to such issues, however, the consequences of voluntary co-consumption have been largely ignored in the animal literature. The primary goal of this work was to characterize a mouse model of binge caffeine and ethanol co-consumption employing the limited-access ‘Drinking-in-the-Dark’ paradigm (DID). Methods Caffeine was added to a 20% alcohol solution via DID. Alcohol/caffeine intake, locomotor behavior, ataxia, anxiety-like behavior, and cognitive function were evaluated as a consequence of co-consumption in adult male C57BL/6J mice. Results Caffeine did not substantially alter binge alcohol intake or resultant BECs, nor did it alter alcohol’s anxiolytic effects on the elevated plus maze or cognitive interfering effects in a novel object recognition task. However, no evidence of alcohol-induced sedation was observed in co-consumption groups that instead demonstrated a highly stimulated state similar to that of caffeine alone. The addition of caffeine was also found to mitigate alcohol-induced ataxia. Conclusions Taken together, our mouse model indicates that binge co-consumption of caffeine and alcohol produces a stimulated, less ataxic and anxious, as well as cognitively altered state; a state that could be of great public health concern. These results appear to resemble the colloquially-identified ‘wide awake drunk’ state that individuals seek via consumption of such beverages. This self-administration model therefore offers the capacity for translationally-valid explorations

  1. Nutrient-induced modulation of gene expression and cellular functions: modeling epigenetic regulation in bovine cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile fatty acids (VFA), especially butyrate, participate in metabolism both as nutrients and as regulators of histone deacetylation. The major biochemical change that occurs in cells treated with butyrate is the global hyperacetylation of histones. One paradigmatic example of the nutrient-epige...

  2. A Rasch Model Analysis of Alcohol Consumption and Problems Across Adolescence and Young Adulthood

    PubMed Central

    Kahler, Christopher W.; Hoeppner, Bettina B.; Jackson, Kristina M.

    2010-01-01

    Background Recent investigations using item response modeling have begun to conceptualize alcohol consumption, problems, and dependence as representing points along a single continuum of alcohol involvement. Such a conceptualization may be of particular benefit to measurement of alcohol involvement in adolescents, but investigations to date have been limited to adult samples and may not generalize to adolescents due to age-related developmental differences. Methods This study used Rasch model analyses to examine the properties of indices of alcohol consumption and problems among 6,353 adolescents, aged 12 to 18 years, in Wave 1 of the Add Health survey. A particular focus was on whether the functioning of items changed when these adolescents were re-interviewed in Wave 3 when they were 18 to 24 years of age. Results Rasch model analyses supported the unidimensionality and additive properties of the items in the Wave 1 data. Comparisons of Wave 1 and Wave 3 data indicated differential item functioning in most of the items such that items related to alcohol consumption were more severe during adolescence, whereas items related to alcohol problems were more severe in young adulthood. Conclusions A valid index of alcohol involvement in adolescents can be constructed combining indices of alcohol consumption and alcohol problems. Such an index covers a range of severity and functions similarly across sex and race/ethnicity. A similar index can be constructed in young adulthood. However, the interpretation of scores must be attentive to developmental differences. In particular, for adolescents, indices of alcohol consumption are relatively closer in severity to indices of alcohol problems than they are among young adults. Thus, alcohol problems are more likely among adolescents than young adults given a similar level of drinking. PMID:19183135

  3. Re-estimating temperature-dependent consumption parameters in bioenergetics models for juvenile Chinook salmon

    USGS Publications Warehouse

    Plumb, John M.; Moffitt, Christine M.

    2015-01-01

    Researchers have cautioned against the borrowing of consumption and growth parameters from other species and life stages in bioenergetics growth models. In particular, the function that dictates temperature dependence in maximum consumption (Cmax) within the Wisconsin bioenergetics model for Chinook Salmon Oncorhynchus tshawytscha produces estimates that are lower than those measured in published laboratory feeding trials. We used published and unpublished data from laboratory feeding trials with subyearling Chinook Salmon from three stocks (Snake, Nechako, and Big Qualicum rivers) to estimate and adjust the model parameters for temperature dependence in Cmax. The data included growth measures in fish ranging from 1.5 to 7.2 g that were held at temperatures from 14°C to 26°C. Parameters for temperature dependence in Cmax were estimated based on relative differences in food consumption, and bootstrapping techniques were then used to estimate the error about the parameters. We found that at temperatures between 17°C and 25°C, the current parameter values did not match the observed data, indicating that Cmax should be shifted by about 4°C relative to the current implementation under the bioenergetics model. We conclude that the adjusted parameters for Cmax should produce more accurate predictions from the bioenergetics model for subyearling Chinook Salmon.

  4. Transient Thermo-fluid Model of Meniscus Behavior and Slag Consumption in Steel Continuous Casting

    NASA Astrophysics Data System (ADS)

    Jonayat, A. S. M.; Thomas, Brian G.

    2014-10-01

    The behavior of the slag layer between the oscillating mold wall, the slag rim, the slag/liquid steel interface, and the solidifying steel shell, is of immense importance for the surface quality of continuous-cast steel. A computational model of the meniscus region has been developed, that includes transient heat transfer, multi-phase fluid flow, solidification of the slag, and movement of the mold during an oscillation cycle. First, the model is applied to a lab experiment done with a "mold simulator" to verify the transient temperature-field predictions. Next, the model is verified by matching with available literature and plant measurements of slag consumption. A reasonable agreement has been observed for both temperature and flow-field. The predictions show that transient temperature behavior depends on the location of the thermocouple during the oscillation relative to the meniscus. During an oscillation cycle, heat transfer variations in a laboratory frame of reference are more severe than experienced by the moving mold thermocouples, and the local heat transfer rate is increased greatly when steel overflows the meniscus. Finally, the model is applied to conduct a parametric study on the effect of casting speed, stroke, frequency, and modification ratio on slag consumption. Slag consumption per unit area increases with increase of stroke and modification ratio, and decreases with increase of casting speed while the relation with frequency is not straightforward. The match between model predictions and literature trends suggests that this methodology can be used for further investigations.

  5. Modeling climate change impact in hospitality sector, using building resources consumption signature

    NASA Astrophysics Data System (ADS)

    Pinto, Armando; Bernardino, Mariana; Silva Santos, António; Pimpão Silva, Álvaro; Espírito Santo, Fátima

    2016-04-01

    Hotels are one of building types that consumes more energy and water per person and are vulnerable to climate change because in the occurrence of extreme events (heat waves, water stress) same failures could compromise the hotel services (comfort) and increase energy cost or compromise the landscape and amenities due to water use restrictions. Climate impact assessments and the development of adaptation strategies require the knowledge about critical climatic variables and also the behaviour of building. To study the risk and vulnerability of buildings and hotels to climate change regarding resources consumption (energy and water), previous studies used building energy modelling simulation (BEMS) tools to study the variation in energy and water consumption. In general, the climate change impact in building is evaluated studying the energy and water demand of the building for future climate scenarios. But, hotels are complex buildings, quite different from each other and assumption done in simplified BEMS aren't calibrated and usually neglect some important hotel features leading to projected estimates that do not usually match hotel sector understanding and practice. Taking account all uncertainties, the use of building signature (statistical method) could be helpful to assess, in a more clear way, the impact of Climate Change in the hospitality sector and using a broad sample. Statistical analysis of the global energy consumption obtained from bills shows that the energy consumption may be predicted within 90% confidence interval only with the outdoor temperature. In this article a simplified methodology is presented and applied to identify the climate change impact in hospitality sector using the building energy and water signature. This methodology is applied to sixteen hotels (nine in Lisbon and seven in Algarve) with four and five stars rating. The results show that is expect an increase in water and electricity consumption (manly due to the increase in

  6. Sexual Preferences in Nutrient Utilization Regulate Oxygen Consumption and Reactive Oxygen Species Generation in Schistosoma mansoni: Potential Implications for Parasite Redox Biology.

    PubMed

    Oliveira, Matheus P; Correa Soares, Juliana B R; Oliveira, Marcus F

    2016-01-01

    Schistosoma mansoni, one of the causative agents of human schistosomiasis, has a unique antioxidant network that is key to parasite survival and a valuable chemotherapeutic target. The ability to detoxify and tolerate reactive oxygen species increases along S. mansoni development in the vertebrate host, suggesting that adult parasites are more exposed to redox challenges than young stages. Indeed, adult parasites are exposed to multiple redox insults generated from blood digestion, activated immune cells, and, potentially, from their own parasitic aerobic metabolism. However, it remains unknown how reactive oxygen species are produced by S. mansoni metabolism, as well as their biological effects on adult worms. Here, we assessed the contribution of nutrients and parasite gender to oxygen utilization pathways, and reactive oxygen species generation in whole unpaired adult S. mansoni worms. We also determined the susceptibilities of both parasite sexes to a pro-oxidant challenge. We observed that glutamine and serum importantly contribute to both respiratory and non-respiratory oxygen utilization in adult worms, but with different proportions among parasite sexes. Analyses of oxygen utilization pathways revealed that respiratory rates were high in male worms, which contrast with high non-respiratory rates in females, regardless nutritional sources. Interestingly, mitochondrial complex I-III activity was higher than complex IV specifically in females. We also observed sexual preferences in substrate utilization to sustain hydrogen peroxide production towards glucose in females, and glutamine in male worms. Despite strikingly high oxidant levels and hydrogen peroxide production rates, female worms were more resistant to a pro-oxidant challenge than male parasites. The data presented here indicate that sexual preferences in nutrient metabolism in adult S. mansoni worms regulate oxygen utilization and reactive oxygen species production, which may differently contribute

  7. Sexual Preferences in Nutrient Utilization Regulate Oxygen Consumption and Reactive Oxygen Species Generation in Schistosoma mansoni: Potential Implications for Parasite Redox Biology

    PubMed Central

    Oliveira, Matheus P.; Correa Soares, Juliana B. R.; Oliveira, Marcus F.

    2016-01-01

    Schistosoma mansoni, one of the causative agents of human schistosomiasis, has a unique antioxidant network that is key to parasite survival and a valuable chemotherapeutic target. The ability to detoxify and tolerate reactive oxygen species increases along S. mansoni development in the vertebrate host, suggesting that adult parasites are more exposed to redox challenges than young stages. Indeed, adult parasites are exposed to multiple redox insults generated from blood digestion, activated immune cells, and, potentially, from their own parasitic aerobic metabolism. However, it remains unknown how reactive oxygen species are produced by S. mansoni metabolism, as well as their biological effects on adult worms. Here, we assessed the contribution of nutrients and parasite gender to oxygen utilization pathways, and reactive oxygen species generation in whole unpaired adult S. mansoni worms. We also determined the susceptibilities of both parasite sexes to a pro-oxidant challenge. We observed that glutamine and serum importantly contribute to both respiratory and non-respiratory oxygen utilization in adult worms, but with different proportions among parasite sexes. Analyses of oxygen utilization pathways revealed that respiratory rates were high in male worms, which contrast with high non-respiratory rates in females, regardless nutritional sources. Interestingly, mitochondrial complex I-III activity was higher than complex IV specifically in females. We also observed sexual preferences in substrate utilization to sustain hydrogen peroxide production towards glucose in females, and glutamine in male worms. Despite strikingly high oxidant levels and hydrogen peroxide production rates, female worms were more resistant to a pro-oxidant challenge than male parasites. The data presented here indicate that sexual preferences in nutrient metabolism in adult S. mansoni worms regulate oxygen utilization and reactive oxygen species production, which may differently contribute

  8. Effect of consumption of the nutrient-dense, freshwater small fish Amblypharyngodon mola on biochemical indicators of vitamin A status in Bangladeshi children: a randomised, controlled study of efficacy.

    PubMed

    Kongsbak, Katja; Thilsted, Shakuntala H; Wahed, Mohammed A

    2008-03-01

    In Bangladesh, some commonly consumed, indigenous, freshwater small fish species (eaten whole with bone, head and eyes) such as mola (Amblypharyngodon mola) are nutrient-dense, containing preformed vitamin A as retinol and especially 3,4-dehydroretinol. The objective of the present randomised, controlled efficacy study was to evaluate the effects of mola on biochemical indicators of vitamin A status. Children (n 196), aged 3-7 years, with serum retinol 0.36-0.75 micromol/l, were randomly allocated to one of three treatment groups to receive a daily test meal (6 d/week for 9 weeks) of rice and vegetable curry (no vitamin A) ad libitum and 50 g fish curry consisting of: (1) mola, 600 retinol activity equivalents (RAE) (using 40 % biological activity of 3,4-dehydroretinol isomers) (experimental group, n 66); (2) rui (Labeo rohita), a large fish (no vitamin A), with added retinyl palmitate, 600 RAE (positive control group, n 65); or (3) rui, 0 RAE (negative control group, n 65). The nutrient compositions of the dishes were analysed. After 9 weeks, no significant treatment effects were observed for serum retinol (P = 0.52) and retinol-binding protein (P = 0.81) in the experimental group compared with the negative control, whereas the positive control improved significantly (P < 0.001). The present results do not suggest conversion of the large amount of 3,4-dehydroretinol in mola curry to retinol. Further research on the functional effect of mola in humans is needed. Mola is a nutrient-dense animal-source food, rich in haem Fe, Zn and especially Ca, thus consumption of mola in Bangladesh should continue to be encouraged.

  9. Agriculture and future riverine nitrogen export to US coastal regions: Insights from the Nutrient Export from WaterSheds Model

    EPA Science Inventory

    We examine contemporary (2000) and future (2030) estimates of coastal N loads in the continental US by the Nutrient Export from WaterSheds (NEWS) model. Future estimates are based on Millennium Ecosystem Assessment (MEA) scenarios and two additional scenarios that reflect “...

  10. A nonhuman primate model of type II excessive alcohol consumption? Part 1. Low cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations and diminished social competence correlate with excessive alcohol consumption.

    PubMed

    Higley, J D; Suomi, S J; Linnoila, M

    1996-06-01

    Developmental, biochemical, and behavioral concomitants of excessive alcohol consumption were investigated using a nonhuman primate model. The variables of interest were: (1) interindividual stability of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) from infancy to adulthood, (2) effect of parental deprivation early in life on adult CSF 5-HIAA concentrations; (3) correlations between CSF 5-HIAA and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations and alcohol consumption; and (4) correlation between the frequency of competent social behaviors and alcohol consumption. Twenty-nine rhesus macaques were reared for their first 6 months either with their mothers or without adults in peer-only conditions. At 6 and 50 months of age, each subject underwent a series of four, 4-day social separations. Cisternal CSF was sampled before and during the first and last separations; concomitantly, observational data were collected on social dominance behavior in the home-cage. When they reached 50 months of age, the monkeys were provided free access to a palatable alcohol solution daily for 1-hr periods before, during, and after the social separations. Before and after the 50-month separations, data were collected on all types of social behavior in the home-cage. Results showed that peer-reared subjects consumed more alcohol than mother-reared subjects during baseline conditions. Mother-reared subjects, however, increased their rates of consumption to equal peer-reared subjects' rates of consumption during the conditions of a social separation stressor. Peer-reared subjects also exhibited lower CSF 5-HIAA concentrations in infancy and adulthood than their mother-reared counterparts. With rearing condition held constant, interindividual differences in CSF 5-HIAA, MHPG, and homovanillic acid were stable from infancy to adulthood, and high rates of alcohol were consumed by the young adult monkeys with low CSF 5-HIAA and MHPG concentrations, particularly when the CSF

  11. Modeling metabolic homeostasis and nutrient sensing in Drosophila: implications for aging and metabolic diseases

    PubMed Central

    Owusu-Ansah, Edward; Perrimon, Norbert

    2014-01-01

    Over the past decade, numerous reports have underscored the similarities between the metabolism of Drosophila and vertebrates, with the identification of evolutionarily conserved enzymes and analogous organs that regulate carbohydrate and lipid metabolism. It is now well established that the major metabolic, energy-sensing and endocrine signaling networks of vertebrate systems are also conserved in flies. Accordingly, studies in Drosophila are beginning to unravel how perturbed energy balance impinges on lifespan and on the ensuing diseases when energy homeostasis goes awry. Here, we highlight several emerging concepts that are at the nexus between obesity, nutrient sensing, metabolic homeostasis and aging. Specifically, we summarize the endocrine mechanisms that regulate carbohydrate and lipid metabolism, and provide an overview of the neuropeptides that regulate feeding behavior. We further describe the various efforts at modeling the effects of high-fat or -sugar diets in Drosophila and the signaling mechanisms involved in integrating organ function. Finally, we draw attention to some of the cardinal discoveries made with these disease models and how these could spur new research questions in vertebrate systems. PMID:24609035

  12. Measurement and mathematical modelling of nutrient level and water quality parameters.

    PubMed

    Alasl, M Kashefi; Khosravi, M; Hosseini, M; Pazuki, G R; Nezakati Esmail Zadeh, R

    2012-01-01

    Physico-chemical water quality parameters and nutrient levels such as water temperature, turbidity, saturated oxygen, dissolved oxygen, pH, chlorophyll-a, salinity, conductivity, total nitrogen and total phosphorus, were measured from April to September 2011 in the Karaj dam area, Iran. Total nitrogen in water was modelled using an artificial neural network system. In the proposed system, water temperature, depth, saturated oxygen, dissolved oxygen, pH, chlorophyll-a, salinity, turbidity and conductivity were considered as input data, and the total nitrogen in water was considered as output. The weights and biases for various systems were obtained by the quick propagation, batch back propagation, incremental back propagation, genetic and Levenberg-Marquardt algorithms. The proposed system uses 144 experimental data points; 70% of the experimental data are randomly selected for training the network and 30% of the data are used for testing. The best network topology was obtained as (9-5-1) using the quick propagation method with tangent transform function. The average absolute deviation percentages (AAD%) are 2.329 and 2.301 for training and testing processes, respectively. It is emphasized that the results of the artificial neural network (ANN) model are compatible with the experimental data.

  13. Hydrological improvements for nutrient and pollutant emission modeling in large scale catchments

    NASA Astrophysics Data System (ADS)

    Höllering, S.; Ihringer, J.

    2012-04-01

    An estimation of emissions and loads of nutrients and pollutants into European water bodies with as much accuracy as possible depends largely on the knowledge about the spatially and temporally distributed hydrological runoff patterns. An improved hydrological water balance model for the pollutant emission model MoRE (Modeling of Regionalized Emissions) (IWG, 2011) has been introduced, that can form an adequate basis to simulate discharge in a hydrologically differentiated, land-use based way to subsequently provide the required distributed discharge components. First of all the hydrological model had to comply both with requirements of space and time in order to calculate sufficiently precise the water balance on the catchment scale spatially distributed in sub-catchments and with a higher temporal resolution. Aiming to reproduce seasonal dynamics and the characteristic hydrological regimes of river catchments a daily (instead of a yearly) time increment was applied allowing for a more process oriented simulation of discharge dynamics, volume and therefore water balance. The enhancement of the hydrological model became also necessary to potentially account for the hydrological functioning of catchments in regard to scenarios of e.g. a changing climate or alterations of land use. As a deterministic, partly physically based, conceptual hydrological watershed and water balance model the Precipitation Runoff Modeling System (PRMS) (USGS, 2009) was selected to improve the hydrological input for MoRE. In PRMS the spatial discretization is implemented with sub-catchments and so called hydrologic response units (HRUs) which are the hydrotropic, distributed, finite modeling entities each having a homogeneous runoff reaction due to hydro-meteorological events. Spatial structures and heterogeneities in sub-catchments e.g. urbanity, land use and soil types were identified to derive hydrological similarities and classify in different urban and rural HRUs. In this way the

  14. Energy consumption and performance models of small Philippine-built rice mills

    SciTech Connect

    Paras, A.S. Jr.

    1984-01-01

    Two simulation models were developed for small rice mills of the conventional disc-cone and rubber-roll equipped designs that range from 0.3 to 1.8 tons-per-hour capacity. These sizes comprise a large proportion of the rice mills in the Philippines. The first, a computer model, evaluated these two types of mills with regard to energy consumption, total and head grain recovery, and processing time. Field and laboratory data taken by research workers and direct measurements by the author were compiled and employed in the development of equations and distribution functions for the variables that make up the subroutines for the models. The results indicated that the energy consumption of small rice mills in the Philippines could be reduced by 5 to 19%, depending on size, without loss of quality in good-performance mills by using one bigger huller and an adjustable separator, and that the output quality of poor performance mills could be improved with just 4% increase in energy consumption by adding a second stage whitener. The second model estimated the cost of milled rice by utilizing Kirchoff's current and voltage laws and energy conservation principles to derive a cost equation involving the material energy and processing cost.

  15. Model of US Army Materiel Command (AMC) energy consumption. Volume 1. Development of monthly energy-consumption equations. Final report

    SciTech Connect

    Sliwinski, B.J.

    1986-03-01

    This report describes the development of equations to relate monthly energy consumption at U.S. Army Materiel Command (AMC) installations to weather and process parameters. Equations were developed using multiple linear regression analysis for the Armament Munitions and Chemical Command (AMCCOM) and Depot Systems Command (DESCOM) major subcommands of AMC. Multiple regression analysis is the process of fitting a curve to a set of data points. This technique, commonly known as least-squares curve fitting, is based on minimizing the sum of the squares of the errors between the data and the fitted equation. Once the regression analysis is performed, it is possible to generate confidence limits about the fitted equation. For example, the 95% confidence limits determine the range of data values that will fall within the limits 95% of the time. The confidence limits are useful in making statistically valid statements about the meaning of future observations. Accuracies of both the individual and the command-level equations are described, and examples for calculating confidence limits of the equations are given. Results in using the equations to predict AMCCOM and DESCOM total energy consumption indicate they provide a useful tool for managing AMC energy use. Lumped data regression was used to analyze energy-consumption data for AMCCOM, and the efforts are now under way to apply it to DESCOM data.

  16. Predator-scent stress, ethanol consumption and the opioid system in an animal model of PTSD.

    PubMed

    Manjoch, Hadar; Vainer, Ella; Matar, Michael; Ifergane, Gal; Zohar, Joseph; Kaplan, Zeev; Cohen, Hagit

    2016-06-01

    Emerging literature points to stress exposure as a potential contributor to the development of alcohol abuse, but animal models have yielded inconsistent results. Converging experimental data indicate that the endogenous opioid system modulates alcohol consumption and stress regulation. The aim of the present study is to examine the interplay between stress exposure, behavioral stress responses, ethanol (EtOH) consumption and the endogenous opioid system in an animal model of posttraumatic stress disorder. Rats were exposed to stress and then tested in a two-bottle free choice (TBC) assay or in a conditioned place preference paradigm. In some experiments, the endogenous opioid system was pharmacologically manipulated prior to stress exposure. The behavioral outcomes of stress exposure were assessed in an elevated plus-maze, with the acoustic startle response, and by monitoring the freezing response to trauma reminder. Immunoreactivity of phosphorylated opioid receptors in hippocampal subregions was also measured. Stress significantly increased the consumption of EtOH in the TBC assay. The severity of the behavioral response to stress was associated with EtOH consumption, cue-triggered freezing response to a trauma reminder, and endogenous levels of phosphorylated opioid receptors in the hippocampus. Pharmacologically manipulating the endogenous opioid system prior to stress exposure attenuated trauma cue-triggered freezing responses and blocked predator scent stress-induced potentiation of EtOH consumption. These data demonstrate a stress-induced potentiation of EtOH self-administration and reveal a clear association between individual patterns of the behavioral response to stress and alcohol preference, while indicating a role for the endogenous opioid system in the neurobiological response to stress. PMID:26965572

  17. Do gamblers eat more salt? Testing a latent trait model of covariance in consumption.

    PubMed

    Goodwin, Belinda C; Browne, Matthew; Rockloff, Matthew; Donaldson, Phillip

    2015-09-01

    A diverse class of stimuli, including certain foods, substances, media, and economic behaviours, may be described as 'reward-oriented' in that they provide immediate reinforcement with little initial investment. Neurophysiological and personality concepts, including dopaminergic dysfunction, reward sensitivity and rash impulsivity, each predict the existence of a latent behavioural trait that leads to increased consumption of all stimuli in this class. Whilst bivariate relationships (co-morbidities) are often reported in the literature, to our knowledge, a multivariate investigation of this possible trait has not been done. We surveyed 1,194 participants (550 male) on their typical weekly consumption of 11 types of reward-oriented stimuli, including fast food, salt, caffeine, television, gambling products, and illicit drugs. Confirmatory factor analysis was used to compare models in a 3×3 structure, based on the definition of a single latent factor (none, fixed loadings, or estimated loadings), and assumed residual covariance structure (none, a-priori / literature based, or post-hoc / data-driven). The inclusion of a single latent behavioural 'consumption' factor significantly improved model fit in all cases. Also confirming theoretical predictions, estimated factor loadings on reward-oriented indicators were uniformly positive, regardless of assumptions regarding residual covariances. Additionally, the latent trait was found to be negatively correlated with the non-reward-oriented indicators of fruit and vegetable consumption. The findings support the notion of a single behavioural trait leading to increased consumption of reward-oriented stimuli across multiple modalities. We discuss implications regarding the concentration of negative lifestyle-related health behaviours. PMID:26551907

  18. Modeling transit bus fuel consumption on the basis of cycle properties.

    PubMed

    Delgado, Oscar F; Clark, Nigel N; Thompson, Gregory J

    2011-04-01

    A method exists to predict heavy-duty vehicle fuel economy and emissions over an "unseen" cycle or during unseen on-road activity on the basis of fuel consumption and emissions data from measured chassis dynamometer test cycles and properties (statistical parameters) of those cycles. No regression is required for the method, which relies solely on the linear association of vehicle performance with cycle properties. This method has been advanced and examined using previously published heavy-duty truck data gathered using the West Virginia University heavy-duty chassis dynamometer with the trucks exercised over limited test cycles. In this study, data were available from a Washington Metropolitan Area Transit Authority emission testing program conducted in 2006. Chassis dynamometer data from two conventional diesel buses, two compressed natural gas buses, and one hybrid diesel bus were evaluated using an expanded driving cycle set of 16 or 17 different driving cycles. Cycle properties and vehicle fuel consumption measurements from three baseline cycles were selected to generate a linear model and then to predict unseen fuel consumption over the remaining 13 or 14 cycles. Average velocity, average positive acceleration, and number of stops per distance were found to be the desired cycle properties for use in the model. The methodology allowed for the prediction of fuel consumption with an average error of 8.5% from vehicles operating on a diverse set of chassis dynamometer cycles on the basis of relatively few experimental measurements. It was found that the data used for prediction should be acquired from a set that must include an idle cycle along with a relatively slow transient cycle and a relatively high speed cycle. The method was also applied to oxides of nitrogen prediction and was found to have less predictive capability than for fuel consumption with an average error of 20.4%.

  19. Influence of nutrient utilization and remineralization stoichiometry on phytoplankton species and carbon export: A modeling study at BATS

    NASA Astrophysics Data System (ADS)

    Salihoglu, B.; Garçon, V.; Oschlies, A.; Lomas, M. W.

    2008-01-01

    The primary objective of this research is to understand the underlying mechanisms of the time-varying flux of carbon in the Sargasso Sea. To address this objective, a one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology as well as nutrient cycles is used at the Bermuda Atlantic Time-series Study (BATS, 31∘40'N, 64∘10'W) site. In this model autotrophic growth is represented by three algal groups and the cell quota approach is used to estimate algal growth and nutrient uptake. This model is tested and evaluated for year 1998 using the bimonthly BATS cruise data. Results show that phosphorus and dissolved organic matter (DOM) are necessary compartments to correctly simulate organic elemental cycles at the BATS site. Model results show that autotrophic eukaryotes and cyanobacteria (i.e. Prochlorococcus and Synechococcus) are the most abundant algal groups and are responsible for 63% and 33% of carbon production in the region, respectively. Sensitivity analyses show that the annual contribution of nitrogen fixation and atmospheric nitrogen deposition to new production is approximately 9% and 3%, respectively. However, the recycled nitrogen and phosphorus are important components of the ecosystem dynamics because sustained growth of algal groups depends on remineralized nutrients which accounts for 75% of the annual carbon production. Nutrient uptake and remineralization stoichiometry can play an important role in determining the surface ocean nutrient distribution. Model results suggest phosphate limitation even during the spring bloom. Phosphate may thus limit the growth of all algal groups throughout the year.

  20. Formal Model for the Reduction of the Dynamic Energy Consumption in Multi-Layer Memory Subsystems

    NASA Astrophysics Data System (ADS)

    Zhu, Hongwei; Luican, Ilie I.; Balasa, Florin; Pradhan, Dhiraj K.

    In real-time data-dominated communication and multimedia processing applications, a multi-layer memory hierarchy is typically used to enhance the system performance and also to reduce the energy consumption. Savings of dynamic energy can be obtained by accessing frequently used data from smaller on-chip memories rather than from large background memories. This paper focuses on the reduction of the dynamic energy consumption in the memory subsystem of multidimensional signal processing systems, starting from the high-level algorithmic specification of the application. The paper presents a formal model which identifies those parts of arrays more intensely accessed, taking also into account the relative lifetimes of the signals. Tested on a two-layer memory hierarchy, this model led to savings of dynamic energy from 40% to over 70% relative to the energy used in the case of flat memory designs.

  1. Human intake fractions of pesticides via greenhouse tomato consumption: comparing model estimates with measurements for Captan.

    PubMed

    Juraske, R; Antón, A; Castells, F; Huijbregts, M A J

    2007-04-01

    Human intake due to pesticide residues in food commodities can be much higher than those related to water consumption and air inhalation, stressing the importance to correctly estimate pesticide uptake into plants and predict subsequent intake by humans. We calculated the human intake fraction of captan via tomato consumption taking into account the time between pesticide application and harvest, the time between harvest and consumption, the absorption of spray deposit on plant surfaces, transfer properties through the cuticle, degradation inside the plant and loss due to food processing. Human population intake fractions due to ingestion were calculated for complete, washed and peeled tomatoes. The calculated intake fractions were compared with measurements derived from an experimental setup in a Mediterranean greenhouse. The fraction of captan applied in the greenhouse as plant treatment that eventually is ingested by the human population is on average 10(-2)-10(-5), depending on the time between pesticide application and ingestion of tomatoes and the processing step considered. Model and experimentally derived intake fractions deviated less than a factor of 2 for complete and washed tomatoes and a factor of 3 for peeled tomatoes. Intake fractions due to air inhalation and consumption of drinking water are expected to be significantly lower (5-9 orders of magnitude) than those induced by the intake of tomatoes in this case study.

  2. Modeling biogeochemical processes in subterranean estuaries: Effect of flow dynamics and redox conditions on submarine groundwater discharge of nutrients

    NASA Astrophysics Data System (ADS)

    Spiteri, Claudette; Slomp, Caroline P.; Tuncay, Kagan; Meile, Christof

    2008-02-01

    A two-dimensional density-dependent reactive transport model, which couples groundwater flow and biogeochemical reactions, is used to investigate the fate of nutrients (NO3-, NH4+, and PO4) in idealized subterranean estuaries representing four end-members of oxic/anoxic aquifer and seawater redox conditions. Results from the simplified model representations show that the prevalent flow characteristics and redox conditions in the freshwater-seawater mixing zone determine the extent of nutrient removal and the input of nitrogen and phosphorus to coastal waters. At low to moderate groundwater velocities, simultaneous nitrification and denitrification can lead to a reversal in the depth of freshwater NO3- and NH4+-PO4 plumes, compared to their original positions at the landward source. Model results suggest that autotrophic denitrification pathways with Fe2+ or FeS2 may provide an important, often overlooked link between nitrogen and phosphorus biogeochemistry through the precipitation of iron oxides and subsequent binding of phosphorus. Simulations also highlight that deviations of nutrient data from conservative mixing curves do not necessarily indicate nutrient removal.

  3. Modeling external carbon addition in biological nutrient removal processes with an extension of the international water association activated sludge model.

    PubMed

    Swinarski, M; Makinia, J; Stensel, H D; Czerwionka, K; Drewnowski, J

    2012-08-01

    The aim of this study was to expand the International Water Association Activated Sludge Model No. 2d (ASM2d) to account for a newly defined readily biodegradable substrate that can be consumed by polyphosphate-accumulating organisms (PAOs) under anoxic and aerobic conditions, but not under anaerobic conditions. The model change was to add a new substrate component and process terms for its use by PAOs and other heterotrophic bacteria under anoxic and aerobic conditions. The Gdansk (Poland) wastewater treatment plant (WWTP), which has a modified University of Cape Town (MUCT) process for nutrient removal, provided field data and mixed liquor for batch tests for model evaluation. The original ASM2d was first calibrated under dynamic conditions with the results of batch tests with settled wastewater and mixed liquor, in which nitrate-uptake rates, phosphorus-release rates, and anoxic phosphorus uptake rates were followed. Model validation was conducted with data from a 96-hour measurement campaign in the full-scale WWTP. The results of similar batch tests with ethanol and fusel oil as the external carbon sources were used to adjust kinetic and stoichiometric coefficients in the expanded ASM2d. Both models were compared based on their predictions of the effect of adding supplemental carbon to the anoxic zone of an MUCT process. In comparison with the ASM2d, the new model better predicted the anoxic behaviors of carbonaceous oxygen demand, nitrate-nitrogen (NO3-N), and phosphorous (PO4-P) in batch experiments with ethanol and fusel oil. However, when simulating ethanol addition to the anoxic zone of a full-scale biological nutrient removal facility, both models predicted similar effluent NO3-N concentrations (6.6 to 6.9 g N/m3). For the particular application, effective enhanced biological phosphorus removal was predicted by both models with external carbon addition but, for the new model, the effluent PO4-P concentration was approximately one-half of that found from

  4. Seasonal Distributions of Global Ocean Chlorophyll and Nutrients: Analysis with a Coupled Ocean General Circulation Biogeochemical, and Radiative Model

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.

    1999-01-01

    A coupled general ocean circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. The model is driven by climatological meteorological conditions, cloud cover, and sea surface temperature. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability, and the interactions among three functional phytoplankton groups (diatoms, chorophytes, and picoplankton) and three nutrient groups (nitrate, ammonium, and silicate). Phytoplankton groups are initialized as homogeneous fields horizontally and vertically, and allowed to distribute themselves according to the prevailing conditions. Basin-scale model chlorophyll results are in very good agreement with CZCS pigments in virtually every global region. Seasonal variability observed in the CZCS is also well represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are also in good conformance, although occasional departures are apparent. Agreement of nitrate distributions with in situ data is even better, including seasonal dynamics, except for the equatorial Atlantic. The good agreement of the model with satellite and in situ data sources indicates that the model dynamics realistically simulate phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization, and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent the great diversity of physical, biological

  5. Optimisation of MSW collection routes for minimum fuel consumption using 3D GIS modelling.

    PubMed

    Tavares, G; Zsigraiova, Z; Semiao, V; Carvalho, M G

    2009-03-01

    Collection of municipal solid waste (MSW) may account for more than 70% of the total waste management budget, most of which is for fuel costs. It is therefore crucial to optimise the routing network used for waste collection and transportation. This paper proposes the use of geographical information systems (GIS) 3D route modelling software for waste collection and transportation, which adds one more degree of freedom to the system and allows driving routes to be optimised for minimum fuel consumption. The model takes into account the effects of road inclination and vehicle weight. It is applied to two different cases: routing waste collection vehicles in the city of Praia, the capital of Cape Verde, and routing the transport of waste from different municipalities of Santiago Island to an incineration plant. For the Praia city region, the 3D model that minimised fuel consumption yielded cost savings of 8% as compared with an approach that simply calculated the shortest 3D route. Remarkably, this was true despite the fact that the GIS-recommended fuel reduction route was actually 1.8% longer than the shortest possible travel distance. For the Santiago Island case, the difference was even more significant: a 12% fuel reduction for a similar total travel distance. These figures indicate the importance of considering both the relief of the terrain and fuel consumption in selecting a suitable cost function to optimise vehicle routing. PMID:18835768

  6. Neuroelectric assessment of nutrient intake.

    PubMed

    Hoffman, L D; Friedmann, A; Saltman, P; Polich, J

    1999-05-01

    Electroencephalographic (EEG) activity and auditory event-related brain potentials (ERPs) were assessed in two groups (n = 12 each) of subjects. The 'food-nutrient' group had fasted from the night before and consumed a 500 cal nutrient drink; the 'control' group consumed breakfast but did not consume any nutrients during the recordings. All subjects were assessed every 15 min for six trial blocks at the same time of day, with the fast/nutrient group measured initially before and after consuming the nutrient drink. No effects of the nutrient drink were obtained on the post-stimulus EEG spectral power or mean frequency measures. However, the fast/nutrient group demonstrated less delta, theta, and alpha-1 power than the no-fast/control group. Increases in spectral power were generally observed across trial blocks especially for the alpha and beta bands, and are consistent with increases in arousal level. P300 amplitude was unaffected by the nutrient consumption, but target stimulus N100 amplitude was smaller for the food-nutrient compared to the control group. Taken together, the results suggest that nutrient consumption does not directly affect EEG or cognitive ERP measures.

  7. Data to support statistical modeling of instream nutrient load based on watershed attributes, southeastern United States, 2002

    USGS Publications Warehouse

    Hoos, Anne B.; Terziotti, Silvia; McMahon, Gerard; Savvas, Katerina; Tighe, Kirsten C.; Alkons-Wolinsky, Ruth

    2008-01-01

    This report presents and describes the digital datasets that characterize nutrient source inputs, environmental characteristics, and instream nutrient loads for the purpose of calibrating and applying a nutrient water-quality model for the southeastern United States for 2002. The model area includes all of the river basins draining to the south Atlantic and the eastern Gulf of Mexico, as well as the Tennessee River basin (referred to collectively as the SAGT area). The water-quality model SPARROW (SPAtially-Referenced Regression On Watershed attributes), developed by the U.S. Geological Survey, uses a regression equation to describe the relation between watershed attributes (predictors) and measured instream loads (response). Watershed attributes that are considered to describe nutrient input conditions and are tested in the SPARROW model for the SAGT area as source variables include atmospheric deposition, fertilizer application to farmland, manure from livestock production, permitted wastewater discharge, and land cover. Watershed and channel attributes that are considered to affect rates of nutrient transport from land to water and are tested in the SAGT SPARROW model as nutrient-transport variables include characteristics of soil, landform, climate, reach time of travel, and reservoir hydraulic loading. Datasets with estimates of each of these attributes for each individual reach or catchment in the reach-catchment network are presented in this report, along with descriptions of methods used to produce them. Measurements of nutrient water quality at stream monitoring sites from a combination of monitoring programs were used to develop observations of the response variable - mean annual nitrogen or phosphorus load - in the SPARROW regression equation. Instream load of nitrogen and phosphorus was estimated using bias-corrected log-linear regression models using the program Fluxmaster, which provides temporally detrended estimates of long-term mean load well

  8. Paternal modeling, household availability, and paternal intake as predictors of fruit, vegetable, and sweetened beverage consumption among African American children.

    PubMed

    Harris, Toni S; Ramsey, Michael

    2015-02-01

    The current study examined how African American fathers' dietary practices were associated with their children's dietary consumption. The sample consisted of one hundred and two African American fathers, who had children between the ages of three and thirteen. The fathers provided self-reports of their consumption of fruits, vegetables, and sugar sweetened beverages; modeling of healthy eating; household availability of foods and beverages; and their children's previously mentioned consumption. Sweetened beverages are considered to be any beverage that contains added sweeteners, high-fructose corn syrup, and/or fruit juice concentrates. Paternal modeling and household availability of food and beverages were measured using subscales from the Comprehensive Feeding Practices Questionnaire (CFPQ). Three separate hierarchical regressions were performed to reveal that child fruit and vegetable consumption was only predicted by parental intake. Child sweetened beverage consumption, however, was predicted by paternal intake and household availability. Modeling did not significantly predict children's consumption of fruits, vegetables, or sweetened beverages. The findings suggest that paternal intake of fruits, vegetables, and sweetened beverages predicts child consumption of fruits, vegetables, and sweetened beverages. Family efforts should be made toward increasing father's consumption of healthy foods while decreasing the consumption and availability of sweetened beverages. PMID:25447009

  9. Bayesian Modeling of the Assimilative Capacity Component of Stream Nutrient Export

    EPA Science Inventory

    Implementing stream restoration techniques and best management practices to reduce nonpoint source nutrients implies enhancement of the assimilative capacity for the stream system. In this paper, a Bayesian method for evaluating this component of a TMDL load capacity is developed...

  10. Quantitative Models for Ecosystem Assessment in Narragansett Bay: Response to Nutrient Loading and Other Stressors

    EPA Science Inventory

    Multiple drivers, including nutrient loading and climate change, affect the Narragansett Bay ecosystem. Managers are interested in understanding the timing and magnitude of these effects, as well as ecosystem responses to restoration actions, such as the capacity and potential fo...

  11. Tree species identity and interactions with neighbors determine nutrient leaching in model tropical forests.

    PubMed

    Ewel, John J; Bigelow, Seth W

    2011-12-01

    An ecosystem containing a mixture of species that differ in phenology, morphology, and physiology might be expected to resist leaching of soil nutrients to a greater extent than one composed of a single species. We tested the effects of species identity and plant-life-form richness on nutrient leaching at a lowland tropical site where deep infiltration averages >2 m year(-1). Three indigenous tree species with contrasting leafing phenologies (evergreen, dry-season deciduous, and wet-season deciduous) were grown in monoculture and together with two other life-forms with which they commonly occur in tropical forests: a palm and a giant, perennial herb. To calculate nutrient leaching over an 11-year period, concentrations of nutrients in soil water were multiplied by drainage rates estimated from a water balance. The effect of plant-life-form richness on retention differed according to tree species identity and nutrient. Nitrate retention was greater in polycultures of the dry-season deciduous tree species (mean of 7.4 kg ha(-1) year(-1) of NO(3)-N lost compared to 12.7 in monoculture), and calcium and magnesium retention were greater in polycultures of the evergreen and wet-season deciduous tree species. Complementary use of light led to intensification of soil exploitation by roots, the main agent responsible for enhanced nutrient retention in some polycultures. Other mechanisms included differences in nutrient demand among species, and avoidance of catastrophic failure due to episodic weather events or pest outbreaks. Even unrealistically simple multi-life-form mimics of tropical forest can safeguard a site's nutrient capital if careful attention is paid to species' characteristics and temporal changes in interspecific interactions. PMID:21691855

  12. Tree species identity and interactions with neighbors determine nutrient leaching in model tropical forests.

    PubMed

    Ewel, John J; Bigelow, Seth W

    2011-12-01

    An ecosystem containing a mixture of species that differ in phenology, morphology, and physiology might be expected to resist leaching of soil nutrients to a greater extent than one composed of a single species. We tested the effects of species identity and plant-life-form richness on nutrient leaching at a lowland tropical site where deep infiltration averages >2 m year(-1). Three indigenous tree species with contrasting leafing phenologies (evergreen, dry-season deciduous, and wet-season deciduous) were grown in monoculture and together with two other life-forms with which they commonly occur in tropical forests: a palm and a giant, perennial herb. To calculate nutrient leaching over an 11-year period, concentrations of nutrients in soil water were multiplied by drainage rates estimated from a water balance. The effect of plant-life-form richness on retention differed according to tree species identity and nutrient. Nitrate retention was greater in polycultures of the dry-season deciduous tree species (mean of 7.4 kg ha(-1) year(-1) of NO(3)-N lost compared to 12.7 in monoculture), and calcium and magnesium retention were greater in polycultures of the evergreen and wet-season deciduous tree species. Complementary use of light led to intensification of soil exploitation by roots, the main agent responsible for enhanced nutrient retention in some polycultures. Other mechanisms included differences in nutrient demand among species, and avoidance of catastrophic failure due to episodic weather events or pest outbreaks. Even unrealistically simple multi-life-form mimics of tropical forest can safeguard a site's nutrient capital if careful attention is paid to species' characteristics and temporal changes in interspecific interactions.

  13. Predictive models of energy consumption in multi-family housing in College Station, Texas

    NASA Astrophysics Data System (ADS)

    Ali, Hikmat Hummad

    Patterns of energy consumption in apartment buildings are different than those in single-family houses. Apartment buildings have different physical characteristics, and their inhabitants have different demographic attributes. This study develops models that predict energy usage in apartment buildings in College Station. This is accomplished by analyzing and identifying the predictive variables that affect energy usage, studying the consumption patterns, and creating formulas based on combinations of these variables. According to the hypotheses and the specific research context, a cross-sectional design strategy is adopted. This choice implies analyses across variations within a sample of fourplex apartments in College Station. The data available for analysis include the monthly billing data along with the physical characteristics of the building, climate data for College Station, and occupant demographic characteristics. A simple random sampling procedure is adopted. The sample size of 176 apartments is drawn from the population in such a way that every possible sample has the same chance of being selected. Statistical methods used to interpret the data include univariate analysis (mean, standard deviation, range, and distribution of data), correlation analysis, regression analysis, and ANOVA (analyses of variance). The results show there are significant differences in cooling efficiency and actual energy consumption among different building types, but there are no significant differences in heating consumption. There are no significant differences in actual energy consumption between student and non-student groups or among ethnic groups. The findings indicate that there are significant differences in actual energy consumption among marital status groups and educational level groups. The multiple regression procedures show there is a significant relationship between normalized annual consumption and the combined variables of floor area, marital status, dead band

  14. Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models1

    PubMed Central

    Robertson, Dale M; Saad, David A

    2011-01-01

    Abstract Nutrient input to the Laurentian Great Lakes continues to cause problems with eutrophication. To reduce the extent and severity of these problems, target nutrient loads were established and Total Maximum Daily Loads are being developed for many tributaries. Without detailed loading information it is difficult to determine if the targets are being met and how to prioritize rehabilitation efforts. To help address these issues, SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed for estimating loads and sources of phosphorus (P) and nitrogen (N) from the United States (U.S.) portion of the Great Lakes, Upper Mississippi, Ohio, and Red River Basins. Results indicated that recent U.S. loadings to Lakes Michigan and Ontario are similar to those in the 1980s, whereas loadings to Lakes Superior, Huron, and Erie decreased. Highest loads were from tributaries with the largest watersheds, whereas highest yields were from areas with intense agriculture and large point sources of nutrients. Tributaries were ranked based on their relative loads and yields to each lake. Input from agricultural areas was a significant source of nutrients, contributing ∼33-44% of the P and ∼33-58% of the N, except for areas around Superior with little agriculture. Point sources were also significant, contributing ∼14-44% of the P and 13-34% of the N. Watersheds around Lake Erie contributed nutrients at the highest rate (similar to intensively farmed areas in the Midwest) because they have the largest nutrient inputs and highest delivery ratio. PMID:22457580

  15. Temperature effects on stocks and stability of a phytoplankton-zooplankton model and the dependence on light and nutrients

    USGS Publications Warehouse

    Norberg, J.; DeAngelis, D.L.

    1997-01-01

    A model of a closed phytoplankton—zooplankton ecosystem was analyzed for effects of temperature on stocks and stability and the dependence of these effects on light and total nutrient concentration of the system. An analysis of the steady state equations showed that the effect of temperature on zooplankton and POM biomass was levelled when primary production is nutrient limited. Temperature increase had a generally negative effect on all biomasses at high nutrient levels due to increased maintenance costs. Nutrient limitation of net primary production is the main factor governing the effect of stocks and flows as well as the stability of the system. All components of the system, except for phytoplankton biomass, are proportional to net production and thus to the net effect of light on photosynthesis. However, temperature determines the slope of that relationship. The resilience of the system was measured by calculating the eigenvalues of the steady state. Under oligotrophic conditions, the system can be stable, but an increase in temperature can cause instability or a decrease in resilience. This conclusion is discussed in the face of recent models that take spatial heterogeneity into account and display far more stable behavior, in better agreement to empirical data. Using simulations, we found that the amplitude of fluctuations of the herbivore stock increases with temperature while the mean biomass and minimum values decrease in comparison with steady state predictions

  16. The Good, the Bad, and the Tiny: A Simple, Mechanistic-Probabilistic Model of Virus-Nutrient Colimitation in Microbes

    PubMed Central

    Cael, B. B.

    2015-01-01

    For phytoplankton and other microbes, nutrient receptors are often the passages through which viruses invade. This presents a bottom-up vs. top-down, co-limitation scenario; how do these would-be-hosts balance minimizing viral susceptibility with maximizing uptake of limiting nutrient(s)? This question has been addressed in the biological literature on evolutionary timescales for populations, but a shorter timescale, mechanistic perspective is lacking, and marine viral literature suggests the strong influence of additional factors, e.g. host size; while the literature on both nutrient uptake and host-virus interactions is expansive, their intersection, of ubiquitous relevance to marine environments, is understudied. I present a simple, mechanistic model from first principles to analyze the effect of this co-limitation scenario on individual growth, which suggests that in environments with high risk of viral invasion or spatial/temporal heterogeneity, an individual host’s growth rate may be optimized with respect to receptor coverage, producing top-down selective pressure on short timescales. The model has general applicability, is suggestive of hypotheses for empirical exploration, and can be extended to theoretical studies of more complex behaviors and systems. PMID:26600042

  17. IMPACT OF IMPROVED FAT-MEAT PRODUCTS CONSUMPTION ON ANTHROPOMETRIC MARKERS AND NUTRIENT INTAKES OF MALE VOLUNTEERS AT INCREASED CARDIOVASCULAR RISK.

    PubMed

    Celada, Paloma; Delgado-Pando, Gonzalo; Olmedilla-Alonso, Begoña; Jiménez-Colmenero, Francisco; Ruperto, Mar; Sánchez-Muniz, Francisco J

    2015-08-01

    Introducción: la carne es una matriz adecuada para la inclusión de ingredientes funcionales. En un estudio no secuencial controlado y aleatorio se evaluó el impacto del consumo de productos cárnicos, en los que se sustituyó la grasa animal por una combinación de aceite de oliva, de linaza y de pescado, sobre la ingesta de energía y nutrientes y sobre los marcadores antropométricos. Métodos: dieciocho voluntarios con elevado riesgo cardiovascular consumieron semanalmente 200 g de salchichas tipo frankfurt y 250 g de paté durante tres períodos sucesivos de 4 semanas (bajo en grasa (RF); enriquecidos en n-3 (n-3RF), y grasa normal (NF)), separados por un lavado de 4 semanas. Se evaluó la ingesta de nutrientes y energía, el índice de alimentación saludable (HEI) y los cambios antropométricos. Resultados: hubo diferencias significativas entre períodos para las tasas de cambio de la grasa corporal y de la relación cintura/cadera (p = 0,018 y p = 0,031, respectivamente), disminuyendo la masa grasa, el perímetro de la cintura y la relación cintura/cadera en el periodo RF, e incrementándose la grasa corporal en el periodo NF (todos p = 0,05). En el período n-3RF las tasas de cambio de IMC y del peso ideal correlacionaron inversa y significativamente (p = 0.003 y p = 0.006, respectivamente) con el cociente hidratos de carbono/AGS. El HEI inicial de las dietas fue muy bajo (valor medio < 60). La contribución energética de carbohidratos, grasa y proteínas fue 40%, 41% y 16%, respectivamente. Más del 33% de los voluntarios no cubrían al inicio el 70% de las RDA para minerales y vitaminas. La intervención mejoró en todos los períodos la ingesta de Zn, Ca, equivalentes de retinol, folatos y vitamina B12. En el período n-3RF incrementó los AGPn-3 y redujo el cociente n-6/n-3. Conclusión: los productos cárnicos con menos grasa o enriquecidos en AGP n-3 son alimentos funcionales para personas con sobrepeso/obesidad, ya que su consumo mejora los

  18. Nutrient delivery to Lake Winnipeg from the Red-Assiniboine River Basin – A binational application of the SPARROW model

    USGS Publications Warehouse

    Benoy, Glenn A; Jenkinson, R. Wayne; Robertson, Dale; Saad, David A.

    2016-01-01

    Excessive phosphorus (TP) and nitrogen (TN) inputs from the Red–Assiniboine River Basin (RARB) have been linked to eutrophication of Lake Winnipeg; therefore, it is important for the management of water resources to understand where and from what sources these nutrients originate. The RARB straddles the Canada–United States border and includes portions of two provinces and three states. This study represents the first binationally focused application of SPAtially Referenced Regressions on Watershed attributes (SPARROW) models to estimate loads and sources of TP and TN by jurisdiction and basin at multiple spatial scales. Major hurdles overcome to develop these models included: (1) harmonization of geospatial data sets, particularly construction of a contiguous stream network; and (2) use of novel calibration steps to accommodate limitations in spatial variability across the model extent and in the number of calibration sites. Using nutrient inputs for a 2002 base year, a RARB TP SPARROW model was calibrated that included inputs from agriculture, forests and wetlands, wastewater treatment plants (WWTPs) and stream channels, and a TN model was calibrated that included inputs from agriculture, WWTPs and atmospheric deposition. At the RARB outlet, downstream from Winnipeg, Manitoba, the majority of the delivered TP and TN came from the Red River Basin (90%), followed by the Upper Assiniboine River and Souris River basins. Agriculture was the single most important TP and TN source for each major basin, province and state. In general, stream channels (historically deposited nutrients and from bank erosion) were the second most important source of TP. Performance metrics for the RARB SPARROW model are similarly robust compared to other, larger US SPARROW models making it a potentially useful tool to address questions of where nutrients originate and their relative contributions to loads delivered to Lake Winnipeg.

  19. Statistical modeling of daily urban water consumption in Hong Kong: Trend, changing patterns, and forecast

    NASA Astrophysics Data System (ADS)

    Wong, Jefferson See; Zhang, Qiang; Chen, Yongqin David

    2010-03-01

    This study attempted to address statistical properties and forecast of daily urban water consumption in Hong Kong from 1990 to 2007. A statistical model was formulated to differentiate the effects of five factors on water use, i.e., trend, seasonality, climatic regression, calendar effect, and autoregression. The postulate of the statistical model is that total water use is made up of base, seasonal, and calendrical water use. Daily urban water consumption in Hong Kong from 1990 to 2001 was modeled and the developed statistical model explains 83% of the variance with six factors: trend (8%), seasonality (27%), climatic regression (2%), day-of-the-week effect (17%), holiday effect (17%), and autoregression (12%). The model was further validated using an independent data set from 2002 to 2007, yielding a R2 of 76%. The results indicated good performance of the developed statistical model in depicting the temporal variations of the urban water use in Hong Kong, offering an improved insight into urban utilization of water resources and acting as the theoretical support for effective urban water resource management in Hong Kong under the changing environment.

  20. Microsensors to the Model Forecasts: Multiscale Embedded Networked Sensing of Nutrients in the Watershed

    NASA Astrophysics Data System (ADS)

    Harmon, T. C.

    2005-12-01

    Hydrologic and water quality observatories are being planned with a vision of enhancing our ability to better understand, forecast and adaptively manage both water quantity and quality. To adequately cover these spatially and temporally variable systems, distributed, embedded sensor networks must be designed with the proper mix (multimodality) of sensors to quantify key system properties, including temperature and chemical distributions, as well as mass and energy fluxes, and to do so across multiple scales. Given resource limitations, process models need to be coupled to the sensor network to interpolate between sensor data. This work focuses on the spatially distributed flux of nutrients, specifically nitrate, in surface-subsurface environments. It begins at the sensor level, describing the development and testing of nitrate microsensors that are scaleable to large, dense sensor networks required to cover heterogeneous watersheds, including associated soil and sediment systems. First and second generation miniature and inexpensive nitrate sensors (ion selective electrodes) fabricated by depositing conducting polymers on carbon substrates are presented in the context of laboratory and field tests. While these sensors are limited to relatively short deployments (4-8 weeks), there are potential strategies for overcoming this problem. Scale-up to one- and three-dimensional soil/sediment sensor arrays is discussed in the context of two deployments: (1) a groundwater quality protection network, where recycled wastewater that is potentially high in nitrate is being used for agricultural irrigation, and (2) nonpoint source nitrate pollution in rivers and groundwater in agricultural watersheds. Recent hardware (wireless transceivers) and software advancements (e.g., network topology design and debugging, energy management) intended for networks spanning 100s of m in space are outlined in these examples. The discussion extends to sensor form factor, in situ calibration

  1. Modelling the effects of land use changes on nutrient export in a Western Australian catchment

    NASA Astrophysics Data System (ADS)

    Zammit, C.; Sivapalan, M.

    2003-04-01

    The estuary of the Swan River in Western Australia is becoming increasingly prone to algal blooms, fish deaths and other problems associated with eutrophication. Eutrophication is an increasing problem in many of the world's waterways and the associated proliferation of algae and weeds can lead to significant loss of amenity in terms of water supply, fisheries and recreation. Phosphorus and nitrogen enrichment are the two most common causes of eutrophication. Both these elements are readily transported in streamflow and their concentrations are strongly dependent on land use within the catchment. The Large Scale Catchment Model (LASCAM) has been developed with the aim of predicting the impacts of land use and climatic changes on the daily trends of streamflow and water quality (salinity, sediments, nutrients, etc.) in large catchments over long time periods. The model has been applied to a rural catchment, Ellen Brook, located in Western Australia. It was used to test and simulate catchment exports under a range of land cover change scenarios that may occur over the next 10 years. The scenarios, which are related to different management options for the catchment are: i) urbanisation following highway development; ii) reforestation of the agricultural area; and iii) reduction in fertilizer applications. The results show that: i) urbanisation increases runoff due to the larger impermeable areas increasing overland flow; ii) phosphorus and nitrogen loads are expected to increase by about 4 to 12 % following urbanisation; iii) full reforestation is expected to reduce phosphorus and nitrogen loads export by 50 to 85%; iv) the greatest reduction of phosphorus and nitrogen export occurs for a relatively small increase of reforestation; v) reduction in fertilizer application may be suitable only for a target of 45% reduction in phosphorus export (or over).

  2. Modeling of Current Consumption in 802.15.4/ZigBee Sensor Motes

    PubMed Central

    Casilari, Eduardo; Cano-García, Jose M.; Campos-Garrido, Gonzalo

    2010-01-01

    Battery consumption is a key aspect in the performance of wireless sensor networks. One of the most promising technologies for this type of networks is 802.15.4/ZigBee. This paper presents an empirical characterization of battery consumption in commercial 802.15.4/ZigBee motes. This characterization is based on the measurement of the current that is drained from the power source under different 802.15.4 communication operations. The measurements permit the definition of an analytical model to predict the maximum, minimum and mean expected battery lifetime of a sensor networking application as a function of the sensor duty cycle and the size of the sensed data. PMID:22219671

  3. Modeling the Effects of Climate Change on Water, Sediment, and Nutrient Discharge from the Maumee River Watershed

    NASA Astrophysics Data System (ADS)

    Cousino, L. K.; Becker, R.; Zmijewski, K. A.

    2013-12-01

    A hydrologic model of the Maumee River watershed in NW Ohio, USA was constructed to test the effects of climate change on water flow and sediment and nutrient loading within the drainage basin. The Maumee River drains a larger area (17,100 km2) than any other watershed in the Great Lakes region before discharging into the Western Basin (WB) of Lake Erie. Approximately 70% of the land within the watershed is agricultural, resulting in excess sediment and nutrient loading in the WB. High nutrient concentrations, especially phosphate concentrations, contribute to harmful algal blooms (HABs) in Lake Erie, which is the source of drinking water for approximately 11 million people. After a decrease in Lake Erie HABs in the late 1980s and early 1990s, toxic cyanobacteria blooms have been prevalent in the WB every summer since 1995. To determine the effects of climate change on streamflow and sediment and nutrient loading in the Maumee River watershed, a Soil and Water Assessment Tool (SWAT) hydrologic model was constructed. Flow and suspended sediment calibrations were performed for 1995-1999 using observed data from four USGS gauging stations. Suspended sediment concentration, which correlates highly with total phosphorus concentration, was used as a proxy for total phosphorus loads. Downscaled climate projections from the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) were inputted into the model to test the effects of climate change on the flow and suspended sediment discharge of the Maumee River. Validation was performed by inputting downscaled climate data for 1975-1999 and comparing the output to observed flow and suspended sediment data from the USGS gauging station at Waterville, Ohio. Model outputs for A1B, A2, and B1 climate scenarios indicate an overall decrease in annual flow over the next century, with higher flow in the winter and spring and lower total flow in the summer. However, model outputs also indicate

  4. Do gamblers eat more salt? Testing a latent trait model of covariance in consumption

    PubMed Central

    Goodwin, Belinda C.; Browne, Matthew; Rockloff, Matthew; Donaldson, Phillip

    2015-01-01

    A diverse class of stimuli, including certain foods, substances, media, and economic behaviours, may be described as ‘reward-oriented’ in that they provide immediate reinforcement with little initial investment. Neurophysiological and personality concepts, including dopaminergic dysfunction, reward sensitivity and rash impulsivity, each predict the existence of a latent behavioural trait that leads to increased consumption of all stimuli in this class. Whilst bivariate relationships (co-morbidities) are often reported in the literature, to our knowledge, a multivariate investigation of this possible trait has not been done. We surveyed 1,194 participants (550 male) on their typical weekly consumption of 11 types of reward-oriented stimuli, including fast food, salt, caffeine, television, gambling products, and illicit drugs. Confirmatory factor analysis was used to compare models in a 3×3 structure, based on the definition of a single latent factor (none, fixed loadings, or estimated loadings), and assumed residual covariance structure (none, a-priori / literature based, or post-hoc / data-driven). The inclusion of a single latent behavioural ‘consumption’ factor significantly improved model fit in all cases. Also confirming theoretical predictions, estimated factor loadings on reward-oriented indicators were uniformly positive, regardless of assumptions regarding residual covariances. Additionally, the latent trait was found to be negatively correlated with the non-reward-oriented indicators of fruit and vegetable consumption. The findings support the notion of a single behavioural trait leading to increased consumption of reward-oriented stimuli across multiple modalities. We discuss implications regarding the concentration of negative lifestyle-related health behaviours. PMID:26551907

  5. Dynamic water quality modelling and uncertainty analysis of phytoplankton and nutrient cycles for the upper South Saskatchewan River.

    PubMed

    Akomeah, Eric; Chun, Kwok Pan; Lindenschmidt, Karl-Erich

    2015-11-01

    The surface water quality of the upper South Saskatchewan River was modelled using Water Quality Analysis Simulation Program (WASP) 7.52. Model calibration and validation were based on samples taken from four long-term water quality stations during the period 2007-2009. Parametric sensitivities in winter and summer were examined using root mean square error (RMSE) and relative entropy. The calibration and validation results show good agreement between model prediction and observed data. The two sensitivity methods confirmed pronounced parametric sensitivity to model state variables in summer compared to winter. Of the 24 parameters examined, dissolved oxygen (DO) and ammonia (NH3-N) are the most influenced variables in summer. Instream kinetic processes including nitrification, nutrient uptake by algae and algae respiration induce a higher sensitivity on DO in summer than in winter. Moreover, in summer, soluble reactive phosphorus (SRP) and chlorophyll-a (Chla) variables are more sensitive to algal processes (nutrient uptake and algae death). In winter however, there exists some degree of sensitivity of algal processes (algae respiration and nutrient uptake) to DO and NH3-N. Results of this study provide information on the state of the river water quality which impacts Lake Diefenbaker and the need for additional continuous monitoring in the river. The results of the sensitivity analysis also provide guidance on most sensitive parameters and kinetic processes that affect eutrophication for preliminary surface water quality modelling studies in cold regions.

  6. Dynamic water quality modelling and uncertainty analysis of phytoplankton and nutrient cycles for the upper South Saskatchewan River.

    PubMed

    Akomeah, Eric; Chun, Kwok Pan; Lindenschmidt, Karl-Erich

    2015-11-01

    The surface water quality of the upper South Saskatchewan River was modelled using Water Quality Analysis Simulation Program (WASP) 7.52. Model calibration and validation were based on samples taken from four long-term water quality stations during the period 2007-2009. Parametric sensitivities in winter and summer were examined using root mean square error (RMSE) and relative entropy. The calibration and validation results show good agreement between model prediction and observed data. The two sensitivity methods confirmed pronounced parametric sensitivity to model state variables in summer compared to winter. Of the 24 parameters examined, dissolved oxygen (DO) and ammonia (NH3-N) are the most influenced variables in summer. Instream kinetic processes including nitrification, nutrient uptake by algae and algae respiration induce a higher sensitivity on DO in summer than in winter. Moreover, in summer, soluble reactive phosphorus (SRP) and chlorophyll-a (Chla) variables are more sensitive to algal processes (nutrient uptake and algae death). In winter however, there exists some degree of sensitivity of algal processes (algae respiration and nutrient uptake) to DO and NH3-N. Results of this study provide information on the state of the river water quality which impacts Lake Diefenbaker and the need for additional continuous monitoring in the river. The results of the sensitivity analysis also provide guidance on most sensitive parameters and kinetic processes that affect eutrophication for preliminary surface water quality modelling studies in cold regions. PMID:26199003

  7. Development and Application of Regression Models for Estimating Nutrient Concentrations in Streams of the Conterminous United States, 1992-2001

    USGS Publications Warehouse

    Spahr, Norman E.; Mueller, David K.; Wolock, David M.; Hitt, Kerie J.; Gronberg, JoAnn M.

    2010-01-01

    Data collected for the U.S. Geological Survey National Water-Quality Assessment program from 1992-2001 were used to investigate the relations between nutrient concentrations and nutrient sources, hydrology, and basin characteristics. Regression models were developed to estimate annual flow-weighted concentrations of total nitrogen and total phosphorus using explanatory variables derived from currently available national ancillary data. Different total-nitrogen regression models were used for agricultural (25 percent or more of basin area classified as agricultural land use) and nonagricultural basins. Atmospheric, fertilizer, and manure inputs of nitrogen, percent sand in soil, subsurface drainage, overland flow, mean annual precipitation, and percent undeveloped area were significant variables in the agricultural basin total nitrogen model. Significant explanatory variables in the nonagricultural total nitrogen model were total nonpoint-source nitrogen input (sum of nitrogen from manure, fertilizer, and atmospheric deposition), population density, mean annual runoff, and percent base flow. The concentrations of nutrients derived from regression (CONDOR) models were applied to drainage basins associated with the U.S. Environmental Protection Agency (USEPA) River Reach File (RF1) to predict flow-weighted mean annual total nitrogen concentrations for the conterminous United States. The majority of stream miles in the Nation have predicted concentrations less than 5 milligrams per liter. Concentrations greater than 5 milligrams per liter were predicted for a broad area extending from Ohio to eastern Nebraska, areas spatially associated with greater application of fertilizer and manure. Probabilities that mean annual total-nitrogen concentrations exceed the USEPA regional nutrient criteria were determined by incorporating model prediction uncertainty. In all nutrient regions where criteria have been established, there is at least a 50 percent probability of exceeding

  8. Using field data to assess model predictions of surface and ground fuel consumption by wildfire in coniferous forests of California

    NASA Astrophysics Data System (ADS)

    Lydersen, Jamie M.; Collins, Brandon M.; Ewell, Carol M.; Reiner, Alicia L.; Fites, Jo Ann; Dow, Christopher B.; Gonzalez, Patrick; Saah, David S.; Battles, John J.

    2014-03-01

    Inventories of greenhouse gas (GHG) emissions from wildfire provide essential information to the state of California, USA, and other governments that have enacted emission reductions. Wildfires can release a substantial amount of GHGs and other compounds to the atmosphere, so recent increases in fire activity may be increasing GHG emissions. Quantifying wildfire emissions however can be difficult due to inherent variability in fuel loads and consumption and a lack of field data of fuel consumption by wildfire. We compare a unique set of fuel data collected immediately before and after six wildfires in coniferous forests of California to fuel consumption predictions of the first-order fire effects model (FOFEM), based on two different available fuel characterizations. We found strong regional differences in the performance of different fuel characterizations, with FOFEM overestimating the fuel consumption to a greater extent in the Klamath Mountains than in the Sierra Nevada. Inaccurate fuel load inputs caused the largest differences between predicted and observed fuel consumption. Fuel classifications tended to overestimate duff load and underestimate litter load, leading to differences in predicted emissions for some pollutants. When considering total ground and surface fuels, modeled consumption was fairly accurate on average, although the range of error in estimates of plot level consumption was very large. These results highlight the importance of fuel load input to the accuracy of modeled fuel consumption and GHG emissions from wildfires in coniferous forests.

  9. Estimating the input of submarine groundwater discharge (SGD) and SGD-derived nutrients in Geoje Bay, Korea using (222)Rn-Si mass balance model.

    PubMed

    Hwang, Dong-Woon; Lee, In-Seok; Choi, Minkyu; Kim, Tae-Hoon

    2016-09-15

    In order to evaluate the main source of nutrients for maintaining the high production in shellfish farming bay, we have measured (222)Rn activities and the concentrations of nutrients in stream water, seawater, and coastal groundwater around Geoje Bay, one of the largest cultivation areas of oyster in the southern sea of Korea in April 2013. Using the (222)Rn and Si mass balance model, the residence time of bay seawater was about 5days and the submarine groundwater discharge (SGD) into the bay was estimated to be approximately 1.8×10(6)m(3) d(-1). The SGD-derived nutrient fluxes contributed approximately 54% for DIN, 5% for DIP, and 50% for DSi of total nutrient input entering into the bay. Thus, our results suggest that SGD is the major source of nutrients in Geoje Bay, and SGD-derived nutrients are very important to support the biological production of this shellfish farming bay. PMID:27377001

  10. Coupling ANIMO and MT3DMS for 3D regional-scale modeling of nutrient transport in soil and groundwater

    NASA Astrophysics Data System (ADS)

    Janssen, G.; Del Val Alonso, L.; Groenendijk, P.; Griffioen, J.

    2012-12-01

    We developed an on-line coupling between the 1D/quasi-2D nutrient transport model ANIMO and the 3D groundwater transport model code MT3DMS. ANIMO is a detailed, process-oriented model code for the simulation of nitrate leaching to groundwater, N- and P-loads on surface waters and emissions of greenhouse gasses. It is the leading nutrient fate and transport code in the Netherlands where it is used primarily for the evaluation of fertilization related legislation. In addition, the code is applied frequently in international research projects. MT3DMS is probably the most commonly used groundwater solute transport package worldwide. The on-line model coupling ANIMO-MT3DMS combines the state-of-the-art descriptions of the biogeochemical cycles in ANIMO with the advantages of using a 3D approach for the transport through the saturated domain. These advantages include accounting for regional lateral transport, considering groundwater-surface water interactions more explicitly, and the possibility of using MODFLOW to obtain the flow fields. An additional merit of the on-line coupling concept is that it preserves feedbacks between the saturated and unsaturated zone. We tested ANIMO-MT3DMS by simulating nutrient transport for the period 1970-2007 in a Dutch agricultural polder catchment covering an area of 118 km2. The transient groundwater flow field had a temporal resolution of one day and was calculated with MODFLOW-MetaSWAP. The horizontal resolution of the model grid was 100x100m and consisted of 25 layers of varying thickness. To keep computation times manageable, we prepared MT3DMS for parallel computing, which in itself is a relevant development for a large community of groundwater transport modelers. For the parameterization of the soil, we applied a standard classification approach, representing the area by 60 units with unique combinations of soil type, land use and geohydrological setting. For the geochemical parameterization of the deeper subsurface, however, we

  11. Assessing the fate of nutrients and carbon in the bioenergy chain through the modeling of biomass growth and conversion.

    PubMed

    François, Jessica; Fortin, Mathieu; Patisson, Fabrice; Dufour, Anthony

    2014-12-01

    A forest growth model was coupled to a model of combined heat and power (CHP) production in a gasification plant developed in Aspen Plus. For a given production, this integrated forest-to-energy model made it possible to predict the annual flows in wood biomass, carbon, and nutrients, including N, S, P, and K, from the forest to the air emissions (NOx, SOx, PAH, etc.) and ash flows. We simulated the bioenergy potential of pure even-aged high-forest stands of European beech, an abundant forest type in Northeastern France. Two forest management practices were studied, a standard-rotation and a shorter-rotation scenario, along with two wood utilizations: with or without fine woody debris (FWD) harvesting. FWD harvesting tended to reduce the forested area required to supply the CHP by 15–22% since larger amounts of energy wood were available for the CHP process, especially in the short-rotation scenario. Because less biomass was harvested, the short-rotation scenario with FWD decreased the nutrient exports per hectare and year by 4–21% compared to standard practices but increased the amount of N, S, and P in the CHP process by 2–9%. This increase in the input nutrient flows had direct consequences on the inorganic air emissions, thus leading to additional NOx and SO2 emissions. This model is a valuable tool for assessing the life cycle inventories of the entire bioenergy chain.

  12. Assessing the fate of nutrients and carbon in the bioenergy chain through the modeling of biomass growth and conversion.

    PubMed

    François, Jessica; Fortin, Mathieu; Patisson, Fabrice; Dufour, Anthony

    2014-12-01

    A forest growth model was coupled to a model of combined heat and power (CHP) production in a gasification plant developed in Aspen Plus. For a given production, this integrated forest-to-energy model made it possible to predict the annual flows in wood biomass, carbon, and nutrients, including N, S, P, and K, from the forest to the air emissions (NOx, SOx, PAH, etc.) and ash flows. We simulated the bioenergy potential of pure even-aged high-forest stands of European beech, an abundant forest type in Northeastern France. Two forest management practices were studied, a standard-rotation and a shorter-rotation scenario, along with two wood utilizations: with or without fine woody debris (FWD) harvesting. FWD harvesting tended to reduce the forested area required to supply the CHP by 15–22% since larger amounts of energy wood were available for the CHP process, especially in the short-rotation scenario. Because less biomass was harvested, the short-rotation scenario with FWD decreased the nutrient exports per hectare and year by 4–21% compared to standard practices but increased the amount of N, S, and P in the CHP process by 2–9%. This increase in the input nutrient flows had direct consequences on the inorganic air emissions, thus leading to additional NOx and SO2 emissions. This model is a valuable tool for assessing the life cycle inventories of the entire bioenergy chain. PMID:25372499

  13. Modelling fuel consumption in kerbside source segregated food waste collection: separate collection and co-collection.

    PubMed

    Chu, T W; Heaven, S; Gredmaier, L

    2015-01-01

    Source separated food waste is a valuable feedstock for renewable energy production through anaerobic digestion, and a variety of collection schemes for this material have recently been introduced. The aim of this study was to identify options that maximize collection efficiency and reduce fuel consumption as part of the overall energy balance. A mechanistic model was developed to calculate the fuel consumption of kerbside collection of source segregated food waste, co-mingled dry recyclables and residual waste. A hypothetical city of 20,000 households was considered and nine scenarios were tested with different combinations of collection frequencies, vehicle types and waste types. The results showed that the potential fuel savings from weekly and fortnightly co-collection of household waste range from 7.4% to 22.4% and 1.8% to 26.6%, respectively, when compared to separate collection. A compartmentalized vehicle split 30:70 always performed better than one with two compartments of equal size. Weekly food waste collection with alternate weekly collection of the recyclables and residual waste by two-compartment collection vehicles was the best option to reduce the overall fuel consumption.

  14. Analysis and modelling of predation on biofilm activated sludge process: Influence on microbial distribution, sludge production and nutrient dosage.

    PubMed

    Revilla, Marta; Galán, Berta; Viguri, Javier R

    2016-11-01

    The influence of predation on the biofilm activated sludge (BAS) process is studied using a unified model that incorporates hydrolysis and predation phenomena into the two stages of the BAS system: moving bed biofilm reactor pre-treatment (bacterial-predator stage) and activated sludge (predator stage). The unified model adequately describes the experimental results obtained in a cellulose and viscose full-scale wastewater plant and has been used to evaluate the role and contribution of predator microorganisms towards removal of COD, nutrient requirements, sludge production and microbial distribution. The results indicate that predation is the main factor responsible for the reduction of both nutrient requirements and sludge production. Furthermore, increasing the sludge retention time (SRT) does not influence the total biomass content in the AS reactor of a BAS process in two different industrial wastewater treatments. PMID:27614580

  15. Analysis and modelling of predation on biofilm activated sludge process: Influence on microbial distribution, sludge production and nutrient dosage.

    PubMed

    Revilla, Marta; Galán, Berta; Viguri, Javier R

    2016-11-01

    The influence of predation on the biofilm activated sludge (BAS) process is studied using a unified model that incorporates hydrolysis and predation phenomena into the two stages of the BAS system: moving bed biofilm reactor pre-treatment (bacterial-predator stage) and activated sludge (predator stage). The unified model adequately describes the experimental results obtained in a cellulose and viscose full-scale wastewater plant and has been used to evaluate the role and contribution of predator microorganisms towards removal of COD, nutrient requirements, sludge production and microbial distribution. The results indicate that predation is the main factor responsible for the reduction of both nutrient requirements and sludge production. Furthermore, increasing the sludge retention time (SRT) does not influence the total biomass content in the AS reactor of a BAS process in two different industrial wastewater treatments.

  16. Integrated modelling and management of nutrients and eutrophication in river basin - coast - sea systems: A southern Baltic Sea perspective

    NASA Astrophysics Data System (ADS)

    Schernewski, Gerald

    2014-05-01

    The Odra river basin (area: 120,000 km2, average discharge: 550 m³/s, annual N-load 60,000 t) and the Oder (Szczecin) Lagoon (687 km²) are the eutrophication hot-spot in the south-western Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of nitrogen and phosphorus management scenarios in the Oder/Odra river basin on coastal and Baltic Sea water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35%) would have positive effects on lagoon water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased potentially toxic, blue-green algae blooms. The presentation will a) summarize recent results (Schernewski et al. 2009, Schernewski et al. 2011, 2012), b) give an overview how the models were used to provide a comprehensive and consistent set of water quality thresholds and maximum allowable riverine loads for the Water Framework Directive and c) will show the implications for an optimised river basin - lagoon quality management.

  17. Comparison of Real World Energy Consumption to Models and Department of Energy Test Procedures

    SciTech Connect

    Goetzler, William; Sutherland, Timothy; Kar, Rahul; Foley, Kevin

    2011-09-01

    This study investigated the real-world energy performance of appliances and equipment as it compared with models and test procedures. The study looked to determine whether the U.S. Department of Energy and industry test procedures actually replicate real world conditions, whether performance degrades over time, and whether installation patterns and procedures differ from the ideal procedures. The study first identified and prioritized appliances to be evaluated. Then, the study determined whether real world energy consumption differed substantially from predictions and also assessed whether performance degrades over time. Finally, the study recommended test procedure modifications and areas for future research.

  18. Annual cycle and budgets of nutrients in the Bohai sea

    NASA Astrophysics Data System (ADS)

    Liang, Zhao; Hao, Wei; Shizuo, Feng

    2002-04-01

    The environmental problems in the Bohai Sea have become more serious in the last decade. High nutrient concentration contributes much to it. A Sino-German cooperation program has been carried out to improve the understanding of the ecosystem by observations and modelling. A three-dimensional ecosystem model, coupled with a physical transport model, is adopted in this study. The simulation for the year 1982 is validated by the data collected in 1982/1983. The simulated annual mean nutrient concentrations are in good agreement with observations. The nutrient concentrations in the bohai Sea, which are crucial to the algal growth, are high in winter and low in summer. There are depletion from spring to summer and elevation from autumn to winter for nutrients. The nutrients’ depletion is a response to the consumption of the phytoplankton bloom in spring. Internal recycle and external compensation affect the nutrient cycle. Their contributions to the nutrient budgets are discussed based on the simulated results. Production and respiration are the most important sink and source of nutrients. The process of photosynthesis consumes 152 kilotons-P and 831.1 kilotons-N while respiration releases 94.5 kilotons-P and 516.6 kilotons-N in the same period. The remineralization of the detritus pool is an important source of nutrient regeneration, It can compensate 23 percent of the nutrient consumed by the production process. The inputs of phosphates and nitrogen from rivers are 0.55 and 52.7 kilotons respectively. The net nutrient budget is -3.05 kilotons-P and 31.6 kilotons-N.

  19. Analyzing the Energy and Power Consumption of Remote Memory Accesses in the OpenSHMEM Model

    SciTech Connect

    Jana, Siddhartha; Hernandez, Oscar R; Poole, Stephen W; Hsu, Chung-Hsing; Chapman, Barbara

    2014-01-01

    PGAS models like OpenSHMEM provide interfaces to explicitly initiate one-sided remote memory accesses among processes. In addition, the model also provides synchronizing barriers to ensure a consistent view of the distributed memory at different phases of an application. The incorrect use of such interfaces affects the scalability achievable while using a parallel programming model. This study aims at understanding the effects of these constructs on the energy and power consumption behavior of OpenSHMEM applications. Our experiments show that cost incurred in terms of the total energy and power consumed depends on multiple factors across the software and hardware stack. We conclude that there is a significant impact on the power consumed by the CPU and DRAM due to multiple factors including the design of the data transfer patterns within an application, the design of the communication protocols within a middleware, the architectural constraints laid by the interconnect solutions, and also the levels of memory hierarchy within a compute node. This work motivates treating energy and power consumption as important factors while designing compute solutions for current and future distributed systems.

  20. Ocean nutrients

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.; Hurd, Catriona L.

    Nutrients provide the chemical life-support system for phytoplankton in the ocean. Together with the carbon fixed during photosynthesis, nutrients provide the other elements, such as N and P, needed to synthesize macromolecules to build cellular constituents such as ribosomes. The makeup of these various biochemicals, such as proteins, pigments, and nucleic acids, together determine the elemental stoichiometry of an individual phytoplankton cell. The stoichiometry of different phytoplankton species or groups will vary depending on the proportions of distinct cellular machinery, such as for growth or resource acquisition, they require for their life strategies. The uptake of nutrients by phytoplankton helps to set the primary productivity, and drives the biological pump, of the global ocean. In the case of nitrogen, the supply of nutrients is categorized as either new or regenerated. The supply of new nitrogen, such as nitrate upwelled from the ocean' interior or biological nitrogen fixation, is equal to the vertical export of particular organic matter from the upper ocean on a timescale of years. Nutrients such as silica can also play a structural role in some phytoplankton groups, such as diatoms, where they are used to synthesize a siliceous frustule that offers some mechanical protection from grazers. In this chapter, we also explore nutrient uptake kinetics, patterns in nutrient distributions in space and time, the biogeochemical cycle of nitrogen, the atmospheric supply of nutrients, departures from the Redfield ratio, and whether nutrient distributions and cycling will be altered in the future

  1. 78 FR 13874 - Watershed Modeling To Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ... Climate Change and Urban Development in 20 U.S. Watersheds AGENCY: Environmental Protection Agency (EPA... Streamflow, Nutrient, and Sediment Loads to Climate Change and Urban Development in 20 U.S. Watersheds (EPA... phosphorus), and sediment loading to a range of plausible mid-21st century climate change and...

  2. Modeling potato root and shoot growth under drought and nutrient stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulating root growth is critical to understand nutrient and water uptake dynamics of major crops, and to improve agricultural decision support tools for natural resource management. Plants invest more assimilated carbon into their root system when under stress in order to explore a greater soil vo...

  3. A dynamic growth model for prediction of nutrient partitioning and manure production in growing-finishing pigs: Model development and evaluation.

    PubMed

    Strathe, A B; Danfær, A; Jørgensen, H; Kebreab, E

    2015-03-01

    Nutrient loading and air emissions from swine operations raise environmental concerns. The objective of the study was to describe and evaluate a mathematical model (Davis Swine Model) of nutrient partitioning and predict manure excretion and composition on a daily basis. State variables of the model were AA, fatty acids, and a central pool of metabolites that supplied substrate for lipid synthesis and oxidation. The model traced the fate of ingested nutrients and water through digestion and intermediary metabolism into body protein, fat, water, and ash, where body protein and fat represented the body constituent pools. It was assumed that fluxes of metabolites follow saturation kinetics, depending on metabolite concentrations. The main inputs to the model were diet nutrient composition, feed intake, water-to-feed ratio, and initial BW. First, the model was challenged with nutrient partitioning data and then with excretion data. The data had 48 different feeding regimes with contrasting energy and lysine intakes at 2 different stages of growth. The overall observed and predicted mean were 109 and 112 g/d for protein deposition and 132 and 136 g/d for lipid deposition respectively, suggesting minor mean bias. Root mean square prediction error (RMSPE) was used in evaluation of the model for its predictive power. The overall RMSPE was 2.2 and 4.1 g/d for protein and lipid deposition, respectively. The excretion database used for evaluation of the model was constructed from 150 digestibility trials using growing-finishing pig diets that had a wide range of nutrient chemical composition. Nutrient and water excretion were quantified using the principle of mass conservation. The average daily observed and predicted manure production was 3.79 and 3.99 kg/d, respectively, with a RMSPE of 0.49 kg/d. There was a good agreement between observed and predicted mean fecal N output (9.9 and 9.8 g/d, respectively). Similarly, the overall observed and predicted mean urine N output

  4. The Thermodynamic Flow-Force Interpretation of Root Nutrient Uptake Kinetics: A Powerful Formalism for Agronomic and Phytoplanktonic Models

    PubMed Central

    Le Deunff, Erwan; Tournier, Pierre-Henri; Malagoli, Philippe

    2016-01-01

    The ion influx isotherms obtained by measuring unidirectional influx across root membranes with radioactive or stable tracers are mostly interpreted by enzyme-substrate-like modeling. However, recent analyses from ion transporter mutants clearly demonstrate the inadequacy of the conventional interpretation of ion isotherms. Many genetically distinct carriers are involved in the root catalytic function. Parameters Vmax and Km deduced from this interpretation cannot therefore be regarded as microscopic parameters of a single transporter, but are instead macroscopic parameters (Vmapp and Kmapp, apparent maximum velocity and affinity constant) that depend on weighted activities of multiple transporters along the root. The flow-force interpretation based on the thermodynamic principle of irreversible processes is an alternative macroscopic modeling approach for ion influx isotherms in which macroscopic parameters Lj (overall conductance of the root system for the substrate j) and πj (thermodynamic parameter when Jj = 0) have a straightforward meaning with respect to the biological sample studied. They characterize the efficiency of the entire root catalytic structure without deducing molecular characteristics. Here we present the basic principles of this theory and how its use can be tested and improved by changing root pre- and post-wash procedures before influx measurements in order to come as close as possible to equilibrium conditions. In addition, the constant values of Vm and Km in the Michaelis-Menten (MM) formalism of enzyme-substrate interpretation do not reflect variations in response to temperature, nutrient status or nutrient regimes. The linear formalism of the flow-force approach, which integrates temperature effect on nutrient uptake, could usefully replace MM formalism in the 1-3-dimension models of plants and phytoplankton. This formalism offers a simplification of parametrization to help find more realistic analytical expressions and numerical

  5. The Thermodynamic Flow-Force Interpretation of Root Nutrient Uptake Kinetics: A Powerful Formalism for Agronomic and Phytoplanktonic Models.

    PubMed

    Le Deunff, Erwan; Tournier, Pierre-Henri; Malagoli, Philippe

    2016-01-01

    The ion influx isotherms obtained by measuring unidirectional influx across root membranes with radioactive or stable tracers are mostly interpreted by enzyme-substrate-like modeling. However, recent analyses from ion transporter mutants clearly demonstrate the inadequacy of the conventional interpretation of ion isotherms. Many genetically distinct carriers are involved in the root catalytic function. Parameters Vmax and Km deduced from this interpretation cannot therefore be regarded as microscopic parameters of a single transporter, but are instead macroscopic parameters (V[Formula: see text] and K[Formula: see text], apparent maximum velocity and affinity constant) that depend on weighted activities of multiple transporters along the root. The flow-force interpretation based on the thermodynamic principle of irreversible processes is an alternative macroscopic modeling approach for ion influx isotherms in which macroscopic parameters Lj (overall conductance of the root system for the substrate j) and πj (thermodynamic parameter when Jj = 0) have a straightforward meaning with respect to the biological sample studied. They characterize the efficiency of the entire root catalytic structure without deducing molecular characteristics. Here we present the basic principles of this theory and how its use can be tested and improved by changing root pre- and post-wash procedures before influx measurements in order to come as close as possible to equilibrium conditions. In addition, the constant values of Vm and Km in the Michaelis-Menten (MM) formalism of enzyme-substrate interpretation do not reflect variations in response to temperature, nutrient status or nutrient regimes. The linear formalism of the flow-force approach, which integrates temperature effect on nutrient uptake, could usefully replace MM formalism in the 1-3-dimension models of plants and phytoplankton. This formalism offers a simplification of parametrization to help find more realistic analytical

  6. Soils, slopes and source rocks: Application of a soil chemistry model to nutrient delivery to rift lakes

    NASA Astrophysics Data System (ADS)

    Harris, Nicholas B.; Tucker, Gregory E.

    2015-06-01

    The topographic evolution of rift basins may be critical to the deposition of lacustrine source rocks such as the organic-rich Lower Cretaceous shales of the South Atlantic margin. Soils have been proposed as a key link between topography and source rock deposition by providing nutrients for the algae growth in rift lakes. Decreasing topographic relief from active rift to late rift has several effects on soils: soils become thicker and finer, erosion of dead surface and soil organic matter decreases, and the fractionation of precipitation between runoff and infiltration may favor increased infiltration. This hypothesis is tested by application of CENTURY, a complex box model that simulates transfer of nutrients within soil pools. The model is first applied to a rainforest soil, with several parameters individually varied. Infiltration experiments show that the concentrations of C, N and P in groundwater decrease rapidly as infiltration decreases, whether due to increased slope or to decreased precipitation. Increased erosion of surface plant litter and topsoil results in substantially decreased nutrient concentrations in groundwater. Increased sand content in soil causes an increase in nutrient concentration. We integrate these variables in analyzing topographic swathes from the Rio Grande Rift, comparing the southern part of the rift, where topography is relatively old and reduced, to the northern rift. C and P concentrations in groundwater increase as slope gradient decreases, resulting in substantially larger C and P concentrations in groundwater in the southern rift than the northern rift. Nitrogen concentrations in groundwater depends on whether infiltration varies as a function of slope gradient; in experiments where the fraction of infiltrated precipitation decreased with increasing slope, N concentrations was also substantially higher in the southern rift; but in experiments where that fraction was held constant, N concentrations was lower in the southern

  7. Development of Nutrient Model for i-Tree Hydro using Sampling Results from the Mianus River Watershed

    NASA Astrophysics Data System (ADS)

    Stephan, E. A.; Endreny, T. A.; Nowak, D. J.

    2013-12-01

    Urbanization has created an 'urban biogeochemistry' with accelerated and imbalanced nutrient cycles, polluted waterways, and compromised ecosystems due to poorly coupled interactions between society and the urban environment. Our research group tests nitrogen and phosphorus cycle algorithms in I-Tree Hydro to quantify the changes in water quality and quantity that result from changes in urbanization and land use. This presentation focuses on i-Tree Hydro nitrogen and phosphorus dynamics with changing tree and green infrastructure cover. The model is tested using water chemistry and land cover analyses from the Mianus River watershed, a 91 sq km area in Bedford, New York and Stamford, Connecticut. Storm samples are taken from areas draining a variety of land uses, and are analyzed for all nitrogen species, as well as in-situ denitrification measurements. Emphasis is placed on best management practices and structures and their effectiveness in storm event nutrient removal; comparisons between drainage areas that have green space and those that do not will be analyzed. This research should inform model simulation of how water chemistry is affected by management decisions, and how land can be best managed to promote effective nutrient cycling.

  8. Atmospheric nutrient input to the Baltic sea from 1850 to 2006: a reconstruction from modeling results and historical data.

    PubMed

    Ruoho-Airola, Tuija; Eilola, Kari; Savchuk, Oleg P; Parviainen, Maija; Tarvainen, Virpi

    2012-09-01

    In this study, a consistent basin-wise monthly time series of the atmospheric nutrient load to the Baltic Sea during 1850-2006 was compiled. Due to the lack of a long time series (1850-1960) of nutrient deposition to the Baltic Sea, the data set was compiled by combining a time series of deposition data at the Baltic Nest Institute from 1970 to 2006, published historical monitoring data and deposition estimates, as well as recent modeled Representative Concentration Pathways (RCP) emission estimates. The procedure for nitrogen compounds included estimation of the deposition in a few intermediate reference years, linear interpolation between them, and the decomposition of annual deposition into a seasonal deposition pattern. As no reliable monitoring results were found for the atmospheric deposition of phosphorus during the early period of our study, we used published estimates for the temporal and spatial pattern of the phosphorus load.

  9. Atmospheric nutrient input to the Baltic sea from 1850 to 2006: a reconstruction from modeling results and historical data.

    PubMed

    Ruoho-Airola, Tuija; Eilola, Kari; Savchuk, Oleg P; Parviainen, Maija; Tarvainen, Virpi

    2012-09-01

    In this study, a consistent basin-wise monthly time series of the atmospheric nutrient load to the Baltic Sea during 1850-2006 was compiled. Due to the lack of a long time series (1850-1960) of nutrient deposition to the Baltic Sea, the data set was compiled by combining a time series of deposition data at the Baltic Nest Institute from 1970 to 2006, published historical monitoring data and deposition estimates, as well as recent modeled Representative Concentration Pathways (RCP) emission estimates. The procedure for nitrogen compounds included estimation of the deposition in a few intermediate reference years, linear interpolation between them, and the decomposition of annual deposition into a seasonal deposition pattern. As no reliable monitoring results were found for the atmospheric deposition of phosphorus during the early period of our study, we used published estimates for the temporal and spatial pattern of the phosphorus load. PMID:22926878

  10. Modeling of the impact of Rhone River nutrient inputs on the dynamics of planktonic diversity

    NASA Astrophysics Data System (ADS)

    Alekseenko, Elena; Baklouti, Melika; Garreau, Pierre; Guyennon, Arnaud; Carlotti, François

    2014-05-01

    conditions (for which the sea surface layer is well mixed). As a first step, these scenarios will allow to investigate the impact of changes in the N:P ratios of the Rhone River on the structure of the planktonic community at short time scale (two years). Acknowledgements The present research is a contribution to the Labex OT-Med (n° ANR-11-LABX-0061) funded by the French Government «Investissements d'Avenir» program of the French National Research Agency (ANR) through the A*MIDEX project (n° ANR-11-IDEX-0001-02). We thank our collegue P. Raimbault for the access to the MOOSE project dataset about the nutrient composition of the Rhone River . References Alekseenko E., Raybaud V., Espinasse B., Carlotti F., Queguiner B., Thouvenin B., Garreau P., Baklouti M. (2014) Seasonal dynamics and stoichiometry of the planktonic community in the NW Mediterranean Sea: a 3D modeling approach. Ocean Dynamics IN PRESS. http://dx.doi.org/10.1007/s10236-013-0669-2 Baklouti M, Diaz F, Pinazo C, Faure V, Quequiner B (2006a) Investigation of mechanistic formulations depicting phytoplankton dynamics for models of marine pelagic ecosystems and description of a new model. Prog Oceanogr 71:1-33 Baklouti M, Faure V, Pawlowski L, Sciandra A (2006b) Investigation and sensitivity analysis of a mechanistic phytoplankton model implemented in a new modular tool (Eco3M) dedicated to biogeochemical modelling. Prog Oceanogr 71:34-58 Lazure P, Dumas F (2008) An external-internal mode coupling for a 3D hydrodynamical model for applications at regional scale (MARS). Adv Water Resour 31(2):233-250 Ludwig, W., Dumont, E., Meybeck, M., Heussner, S. (2009). River discharges of water and nutrients to the Mediterranean and Black Sea: Major drivers for ecosystem changes during past and future decades? Progress in Oceanography 80, pp. 199-217 Malanotte-Rizoli, P. and Pan-Med Group. (2012) Physical forcing and physical/biochemical variability of the Mediterranean Sea : A review of unresolved issues and directions of

  11. FEM-based oxygen consumption and cell viability models for avascular pancreatic islets

    PubMed Central

    Buchwald, Peter

    2009-01-01

    Background The function and viability of cultured, transplanted, or encapsulated pancreatic islets is often limited by hypoxia because these islets have lost their vasculature during the isolation process and have to rely on gradient-driven passive diffusion, which cannot provide adequate oxygen transport. Pancreatic islets (islets of Langerhans) are particularly susceptible due to their relatively large size, large metabolic demand, and increased sensitivity to hypoxia. Here, finite element method (FEM) based multiphysics models are explored to describe oxygen transport and cell viability in avascular islets both in static and in moving culture media. Methods Two- and three-dimensional models were built in COMSOL Multiphysics using the convection and diffusion as well as the incompressible Navier-Stokes fluid dynamics application modes. Oxygen consumption was assumed to follow Michaelis-Menten-type kinetics and to cease when local concentrations fell below a critical threshold; in a dynamic model, it was also allowed to increase with increasing glucose concentration. Results Partial differential equation (PDE) based exploratory cellular-level oxygen consumption and cell viability models incorporating physiologically realistic assumptions have been implemented for fully scaled cell culture geometries with 100, 150, and 200 μm diameter islets as representative. Calculated oxygen concentrations and intra-islet regions likely to suffer from hypoxia-related necrosis obtained for traditional flask-type cultures, oxygen-permeable silicone-rubber membrane bottom cultures, and perifusion chambers with flowing media and varying incoming glucose levels are presented in detail illustrated with corresponding colour-coded figures and animations. Conclusion Results of the computational models are, as a first estimate, in good quantitative agreement with existing experimental evidence, and they confirm that during culture, hypoxia is often a problem for non-vascularised islet

  12. Towards an Agro-Industrial Ecology: A review of nutrient flow modelling and assessment tools in agro-food systems at the local scale.

    PubMed

    Fernandez-Mena, Hugo; Nesme, Thomas; Pellerin, Sylvain

    2016-02-01

    Improvement in nutrient recycling in agriculture is essential to maintain food production while minimising nutrient pollution of the environment. For this purpose, understanding and modelling nutrient cycles in food and related agro-industrial systems is a crucial task. Although nutrient management has been addressed at the plot and farm scales for many years now in the agricultural sciences, there is a need to upscale these approaches to capture the additional drivers of nutrient cycles that may occur at the local, i.e. district, scale. Industrial ecology principles provide sound bases to analyse nutrient cycling in complex systems. However, since agro-food social-ecological systems have specific ecological and social dimensions, we argue that a new field, referred to as "Agro-Industrial Ecology", is needed to study these systems. In this paper, we review the literature on nutrient cycling in complex social-ecological systems that can provide a basis for Agro-Industrial Ecology. We identify and describe three major approaches: Environmental Assessment tools, Stock and Flow Analysis methods and Agent-based models. We then discuss their advantages and drawbacks for assessing and modelling nutrient cycles in agro-food systems in terms of their purpose and scope, object representation and time-spatial dynamics. We finally argue that combining stock-flow methods with both agent-based models and environmental impact assessment tools is a promising way to analyse the role of economic agents on nutrient flows and losses and to explore scenarios that better close the nutrient cycles at the local scale.

  13. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    NASA Astrophysics Data System (ADS)

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2014-12-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay watershed (CBW), which is located in the mid-Atlantic US, winter cover crop use has been emphasized, and federal and state cost-share programs are available to farmers to subsidize the cost of cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops to improve water quality at the watershed scale (~ 50 km2) and to identify critical source areas of high nitrate export. A physically based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data to simulate hydrological processes and agricultural nutrient cycling over the period of 1990-2000. To accurately simulate winter cover crop biomass in relation to growing conditions, a new approach was developed to further calibrate plant growth parameters that control the leaf area development curve using multitemporal satellite-based measurements of species-specific winter cover crop performance. Multiple SWAT scenarios were developed to obtain baseline information on nitrate loading without winter cover crops and to investigate how nitrate loading could change under different winter cover crop planting scenarios, including different species, planting dates, and implementation areas. The simulation results indicate that winter cover crops have a negligible impact on the water budget but significantly reduce nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading from agricultural lands was approximately 14 kg ha-1, but decreased to 4.6-10.1 kg ha-1 with cover crops resulting in a reduction rate of 27-67% at the watershed scale. Rye was the most effective species, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of cover crops (~ 30

  14. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    NASA Astrophysics Data System (ADS)

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2013-11-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay Watershed (CBW), which is located in the Mid-Atlantic US, winter cover crop use has been emphasized and federal and state cost-share programs are available to farmers to subsidize the cost of winter cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops at the watershed scale and to identify critical source areas of high nitrate export. A physically-based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data and satellite-based estimates of winter cover crop species performance to simulate hydrological processes and nutrient cycling over the period of 1991-2000. Multiple scenarios were developed to obtain baseline information on nitrate loading without winter cover crops planted and to investigate how nitrate loading could change with different winter cover crop planting scenarios, including different species, planting times, and implementation areas. The results indicate that winter cover crops had a negligible impact on water budget, but significantly reduced nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading was approximately 14 kg ha-1, but it decreased to 4.6-10.1 kg ha-1 with winter cover crops resulting in a reduction rate of 27-67% at the watershed scale. Rye was most effective, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of winter cover crops (~30 days of additional growing days) was crucial, as it lowered nitrate export by an additional ~2 kg ha-1 when compared to late planting scenarios. The effectiveness of cover cropping increased with increasing extent of winter cover crop implementation. Agricultural fields with well-drained soils and those

  15. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    USGS Publications Warehouse

    Yeo, In-Young; Lee, Sangchui; Sadeghi, Ali M.; Beeson, Peter C.; Hively, W. Dean; McCarty, Greg W.; Lang, Megan W.

    2013-01-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay Watershed (CBW), which is located in the Mid-Atlantic US, winter cover crop use has been emphasized and federal and state cost-share programs are available to farmers to subsidize the cost of winter cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops at the watershed scale and to identify critical source areas of high nitrate export. A physically-based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data and satellite-based estimates of winter cover crop species performance to simulate hydrological processes and nutrient cycling over the period of 1991–2000. Multiple scenarios were developed to obtain baseline information on nitrate loading without winter cover crops planted and to investigate how nitrate loading could change with different winter cover crop planting scenarios, including different species, planting times, and implementation areas. The results indicate that winter cover crops had a negligible impact on water budget, but significantly reduced nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading was approximately 14 kg ha−1, but it decreased to 4.6–10.1 kg ha−1 with winter cover crops resulting in a reduction rate of 27–67% at the watershed scale. Rye was most effective, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of winter cover crops (~30 days of additional growing days) was crucial, as it lowered nitrate export by an additional ~2 kg ha−1 when compared to late planting scenarios. The effectiveness of cover cropping increased with increasing extent of winter cover crop implementation. Agricultural fields with well-drained soils

  16. Comparative quantification of oxygen release by wetland plants: electrode technique and oxygen consumption model.

    PubMed

    Wu, Haiming; Liu, Jufeng; Zhang, Jian; Li, Cong; Fan, Jinlin; Xu, Xiaoli

    2014-01-01

    Understanding oxygen release by plants is important to the design of constructed wetlands for wastewater treatment. Lab-scale systems planted with Phragmites australis were studied to evaluate the amount of oxygen release by plants using electrode techniques and oxygen consumption model. Oxygen release rate (0.14 g O2/m(2)/day) measured using electrode techniques was much lower than that (3.94-25.20 gO2/m(2)/day) calculated using the oxygen consumption model. The results revealed that oxygen release by plants was significantly influenced by the oxygen demand for the degradation of pollutants, and the oxygen release rate increased with the rising of the concentration of degradable materials in the solution. The summary of the methods in qualifying oxygen release by wetland plants demonstrated that variations existed among different measuring methods and even in the same measuring approach. The results would be helpful for understanding the contribution of plants in constructed wetlands toward actual wastewater treatment.

  17. Global Modeling of Withdrawal, Allocation and Consumptive Use of Surface Water and Groundwater Resources

    NASA Astrophysics Data System (ADS)

    Wada, Y.; Wisser, D.; Bierkens, M. F.

    2014-12-01

    To sustain growing food demand and increasing standard of living, global water withdrawal and consumptive water use have been increasing rapidly. To analyze the human perturbation on water resources consistently over large scales, a number of macro-scale hydrological models (MHMs) have been developed in recent decades. However, few models consider the interaction between terrestrial water fluxes, and human activities and associated water use, and even fewer models distinguish water use from surface water and groundwater resources. Here, we couple a global water demand model with a global hydrological model and dynamically simulate daily water withdrawal and consumptive water use over the period 1979-2010, using two re-analysis products: ERA-Interim and MERRA. We explicitly take into account the mutual feedback between supply and demand, and implement a newly developed water allocation scheme to distinguish surface water and groundwater use. Moreover, we include a new irrigation scheme, which works dynamically with a daily surface and soil water balance, and incorporate the newly available extensive global reservoir data set (GRanD). Simulated surface water and groundwater withdrawals generally show good agreement with reported national and sub-national statistics. The results show a consistent increase in both surface water and groundwater use worldwide, with a more rapid increase in groundwater use since the 1990s. Human impacts on terrestrial water storage (TWS) signals are evident, altering the seasonal and inter-annual variability. This alteration is particularly large over heavily regulated basins such as the Colorado and the Columbia, and over the major irrigated basins such as the Mississippi, the Indus, and the Ganges. Including human water use and associated reservoir operations generally improves the correlation of simulated TWS anomalies with those of the GRACE observations.

  18. Rodent Working Heart Model for the Study of Myocardial Performance and Oxygen Consumption.

    PubMed

    DeWitt, Elizabeth S; Black, Katherine J; Kheir, John N

    2016-01-01

    Isolated working heart models have been used to understand the effects of loading conditions, heart rate and medications on myocardial performance in ways that cannot be accomplished in vivo. For example, inotropic medications commonly also affect preload and afterload, precluding load-independent assessments of their myocardial effects in vivo. Additionally, this model allows for sampling of coronary sinus effluent without contamination from systemic venous return, permitting assessment of myocardial oxygen consumption. Further, the advent of miniaturized pressure-volume catheters has allowed for the precise quantification of markers of both systolic and diastolic performance. We describe a model in which the left ventricle can be studied while performing both volume and pressure work under controlled conditions. In this technique, the heart and lungs of a Sprague-Dawley rat (weight 300-500 g) are removed en bloc under general anesthesia. The aorta is dissected free and cannulated for retrograde perfusion with oxygenated Krebs buffer. The pulmonary arteries and veins are ligated and the lungs removed from the preparation. The left atrium is then incised and cannulated using a separate venous cannula, attached to a preload block. Once this is determined to be leak-free, the left heart is loaded and retrograde perfusion stopped, creating the working heart model. The pulmonary artery is incised and cannulated for collection of coronary effluent and determination of myocardial oxygen consumption. A pressure-volume catheter is placed into the left ventricle either retrograde or through apical puncture. If desired, atrial pacing wires can be placed for more precise control of heart rate. This model allows for precise control of preload (using a left atrial pressure block), afterload (using an afterload block), heart rate (using pacing wires) and oxygen tension (using oxygen mixtures within the perfusate). PMID:27584550

  19. Nutrient management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient management has been defined as “the science and art directed to link soil, crop, weather and hydrologic factors with cultural, irrigation and soil and water conservation practices to achieve the goals of optimizing nutrient use efficiency, yields, crop quality, and economic returns, while r...

  20. Available nutrients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar technology may contribute to the recovery and recycling of plant nutrients and thus add a fertilizer value to the biochar. Total nutrient content in biochars varies greatly and is mainly dependent on feedstock elemental composition and to a lesser extent on pyrolysis conditions. Availability...

  1. [Formulation and evalution of a mathematical model to predict losses of nutrients during the thermal processing of canned food].

    PubMed

    Barreiro, J A; Salas, M G; Herrera Morám, I

    1977-09-01

    The purpose of this paper was the development of a mathematical model to predict losses of nutrients with first orden degradation kinetics during the thermal processing of conduction-heated foods. The model do not require experimental heat penetration data and operate for any possible case. It was evaluated experimentally for different thermal processes, being all the results within the 90% confidence interval on the mean experimental values. These results were obtained with a Fortran IV computer program elaborated for this purpose. The duration of this program was two minutes and tem seconds in a PDP 11/45 computer and was more efficient than others presented in the literature.

  2. Comparing SWAT and InVEST models for water yield and nutrient export: When is a simple model good enough for decision support?

    NASA Astrophysics Data System (ADS)

    Keeler, B.; Dalzell, B. J.; Pennington, D.; Johnson, K.; Polasky, S.

    2013-12-01

    Tools that link land use and management changes with effects on water quantity and quality are in high demand. These tools are used to inform a variety of decisions from regulatory action to informing investments in conservation. However, not all managers or researchers have the time, expertise, or data availability to run complex hydrologic models. This raises the question: When are simple models good enough for decision support? We evaluated two hydrologic models commonly used to predict how land use and land management decisions affect water yield and nutrient export. We compare the continuous time model SWAT (Soil and Water Assessment Tool) that operates on a daily time step with the annual water yield and nutrient retention models in InVEST (Integrated Valuation of Environmental Services and Tradeoffs). We ran each model on two watersheds in Minnesota dominated by row crop agriculture. We calibrated each model to observed data for a baseline land use scenario and then compared predicted water yield and the export of nitrogen and phosphorus from four alternative conservation scenarios. We found good agreement between InVEST and SWAT for scenarios where lands were taken out of corn and soybean production and converted to perennial cover. The two models differed in their modeled nutrient export from scenarios that employed riparian buffers along all waterways. In these scenarios, InVEST predicted much higher reductions in nutrient loading than SWAT. Our analysis highlights key differences between the models in both their structure and assumptions, and provides insights into the value of additional model complexity across a range of decision contexts.

  3. Personalizing nutrient intakes of formula-fed infants: breast milk as a model.

    PubMed

    Lönnerdal, Bo

    2008-01-01

    The growth pattern of formula-fed infants is quite different from that of breastfed infants. There may be several reasons for this difference, ranging from different endocrine responses to feeding and the presence of growth factors in breast milk to different control of food intake, but it is highly likely that differences in nutrient composition of the food (breast milk or formula) have major effects on growth. In most countries infant formula is used more or less exclusively up to 6 months of age and as part of the diet up to 12 months of age and during this period its composition remains the same. In striking contrast, the nutrient composition of breast milk changes during lactation, most dramatically during early lactation, but with pronounced differences throughout lactation for many nutrients. It is a goal that the performance of formulafed infants should be as similar to that of breastfed infants as possible, and attempts have been made to modify the composition of infant formula to achieve this goal. However, there has been no systematic attempt to gradually change the composition of infant formula in a manner similar to the changing pattern of breast milk. This represents a technical and nutritional challenge, but is now possible.

  4. Integrated Urban Nutrient Management

    NASA Astrophysics Data System (ADS)

    Nhapi, I.; Veenstra, S.; Siebel, M. A.; Gijzen, H. J.

    Most cities, especially from the developing countries, are facing serious problems with the management of nutrients, necessitating an urgent review of current waste management systems. Whilst highly efficient technologies are available, the inclusion of these in a well-thought out and systematic approach is necessary to contain the nutrient influxes and outfluxes from towns. Five intervention measures are proposed in this paper. The first is to manage the use and generation of nutrients by drastically minimising water consumption and employing other cleaner production approaches. The second deals with the optimal reuse of nutrients and water at the smallest possible level, like at the household and on-plot level. The second option is to covert the waste into something useful for reuse, and, where not possible, to something which is envi- ronmentally neutral. This involves treatment, but applying technologies that makes the best use of side products via reuse. Where the first three options will have failed, two least preferred options could be used. Waste can be dispersed or diluted to enhance self-purification capacities of downstream water bodies. The last option is to store the wastewater for some parts of the year when there is water shortage to allow for polishing during the standing period. The success of urban nutrient planning requires an integrated approach, proving specific solutions to specific situations. This, in turn, requires appropriate institutional responses.

  5. Multiple regression analysis in modelling of carbon dioxide emissions by energy consumption use in Malaysia

    NASA Astrophysics Data System (ADS)

    Keat, Sim Chong; Chun, Beh Boon; San, Lim Hwee; Jafri, Mohd Zubir Mat

    2015-04-01

    Climate change due to carbon dioxide (CO2) emissions is one of the most complex challenges threatening our planet. This issue considered as a great and international concern that primary attributed from different fossil fuels. In this paper, regression model is used for analyzing the causal relationship among CO2 emissions based on the energy consumption in Malaysia using time series data for the period of 1980-2010. The equations were developed using regression model based on the eight major sources that contribute to the CO2 emissions such as non energy, Liquefied Petroleum Gas (LPG), diesel, kerosene, refinery gas, Aviation Turbine Fuel (ATF) and Aviation Gasoline (AV Gas), fuel oil and motor petrol. The related data partly used for predict the regression model (1980-2000) and partly used for validate the regression model (2001-2010). The results of the prediction model with the measured data showed a high correlation coefficient (R2=0.9544), indicating the model's accuracy and efficiency. These results are accurate and can be used in early warning of the population to comply with air quality standards.

  6. Relations among stress, coping strategies, coping motives, alcohol consumption and related problems: a mediated moderation model.

    PubMed

    Corbin, William R; Farmer, Nicole M; Nolen-Hoekesma, Susan

    2013-04-01

    Although prominent models of alcohol use and abuse implicate stress as an important motivator of alcohol consumption, research has not consistently identified a relationship between stress and drinking outcomes. Presumably stress leads to heavier alcohol consumption and related problems primarily for individuals who lack other adaptive methods for coping effectively with stressful experiences. To test this hypothesis, we examined four adaptive coping approaches (active coping, planning, suppression of competing activities, and restraint), as predictors of alcohol use and related problems as well as moderators of relations between stress and drinking outcomes in an undergraduate population (N=225). Further, we examined coping motives for drinking as potential mediators of the effects of coping strategies as well as stress by coping strategy interactions. Analyses supported both restraint and suppression of competing activities as moderators of the influence of stress on alcohol use but not problems. The stress by restraint interaction was also evident in the prediction of coping motives, and coping motives were related to higher levels of both weekly drinking and alcohol-related problems. Finally, coping motives for drinking served to mediate the stress by restraint interaction on weekly drinking. Overall, these results suggest that efforts to suppress competing activities and restrain impulsive responses in the face of stress may reduce the risk for heavy drinking during the transition from high school to college.

  7. A generic model to describe the dynamics of nutrient concentrations within stemwood across an age series of a eucalyptus hybrid.

    PubMed

    Saint-Andre, Laurent; Laclau, Jean-Paul; Deleporte, Philippe; Ranger, Jacques; Gouma, Raphaël; Saya, Aubin; Joffre, Richard

    2002-07-01

    Nutrient concentrations (N, P, K) were determined within stemwood in an age series of eucalyptus stands. Four trees per stand were selected according to their size to represent the whole range of basal areas in 1-, 2-, 3-, 4-, 5-, 6- and 7-year-old stands. Cross-sections were sampled every 4 m from the ground to the top of the tree, and chemical analyses were performed for each annual ring in the cross-sections. We constructed a new and generic model to describe the dynamics of nutrient concentrations within the stemwood. Three main parameters were used: (1) the initial concentration of the ring, Ic; (2) the final concentration of the ring at harvest, Fc; and (3) the rate of change in concentration, k. The model is very flexible and was adapted to describe N, P and K concentrations within the stems, and their dynamics over time. An analysis of the parameters showed that k was constant for a given nutrient. Ic varied with height within the tree for P, whereas for N and K it was a function of: (1) the age of the tree when the ring was initiated: and (2) height within the tree. Fc was constant for N, and dependent on the age of the tree when the ring was initiated for K and P. The final models showed a low Root Mean Square Error for a limited number of parameters (less than seven). When validated on an independent sample, the models were shown to have high predictive quality. PMID:12125774

  8. A new model of reaction-driven cracking: fluid volume consumption and tensile failure during serpentinization

    NASA Astrophysics Data System (ADS)

    Eichenbaum-Pikser, J. M.; Spiegelman, M. W.; Kelemen, P. B.; Wilson, C. R.

    2013-12-01

    Reactive fluid flow plays an important role in a wide range of geodynamic processes, such as melt migration, formation of hydrous minerals on fault surfaces, and chemical weathering. These processes are governed by the complex coupling between fluid transport, reaction, and solid deformation. Reaction-driven cracking is a potentially critical feedback mechanism, by which volume change associated with chemical reaction drives fracture in the surrounding rock. It has been proposed to play a role in both serpentinization and carbonation of peridotite, motivating consideration of its application to mineral carbon sequestration. Previous studies of reactive cracking have focused on the increase in solid volume, and as such, have considered failure in compression. However, if the consumption of fluid is considered in the overall volume budget, the reaction can be net volume reducing, potentially leading to failure in tension. To explore these problems, we have formulated and solved a 2-D model of coupled porous flow, reaction kinetics, and elastic deformation using the finite element model assembler TerraFERMA (Wilson et al, G3 2013 submitted). The model is applied to the serpentinization of peridotite, which can be reasonably approximated as the transfer of a single reactive component (H2O) between fluid and solid phases, making it a simple test case to explore the process. The behavior of the system is controlled by the competition between the rate of volume consumption by the reaction, and the rate of volume replacement by fluid transport, as characterized by a nondimensional parameter χ, which depends on permeability, reaction rate, and the bulk modulus of the solid. Large values of χ correspond to fast fluid transport relative to reaction rate, resulting in a low stress, volume replacing regime. At smaller values of χ, fluid transport cannot keep up with the reaction, resulting in pore fluid under-pressure and tensile solid stresses. For the range of χ relevant

  9. A decision support model for improving a multi-family housing complex based on CO2 emission from electricity consumption.

    PubMed

    Hong, Taehoon; Koo, Choongwan; Kim, Hyunjoong

    2012-12-15

    The number of deteriorated multi-family housing complexes in South Korea continues to rise, and consequently their electricity consumption is also increasing. This needs to be addressed as part of the nation's efforts to reduce energy consumption. The objective of this research was to develop a decision support model for determining the need to improve multi-family housing complexes. In this research, 1664 cases located in Seoul were selected for model development. The research team collected the characteristics and electricity energy consumption data of these projects in 2009-2010. The following were carried out in this research: (i) using the Decision Tree, multi-family housing complexes were clustered based on their electricity energy consumption; (ii) using Case-Based Reasoning, similar cases were retrieved from the same cluster; and (iii) using a combination of Multiple Regression Analysis, Artificial Neural Network, and Genetic Algorithm, the prediction performance of the developed model was improved. The results of this research can be used as follows: (i) as basic research data for continuously managing several energy consumption data of multi-family housing complexes; (ii) as advanced research data for predicting energy consumption based on the project characteristics; (iii) as practical research data for selecting the most optimal multi-family housing complex with the most potential in terms of energy savings; and (iv) as consistent and objective criteria for incentives and penalties.

  10. Recommendations from Friends Anytime and Anywhere: Toward a Model of Contextual Offer and Consumption Values

    PubMed Central

    Shen, Xiao-Liang; Wang, Nan

    2013-01-01

    Abstract The ubiquity and portability of mobile devices provide additional opportunities for information retrieval. People can easily access mobile applications anytime and anywhere when they need to acquire specific context-aware recommendations (contextual offer) from their friends. This study, thus, represents an initial attempt to understand users' acceptance of a mobile-based social reviews platform, where recommendations from friends can be obtained with mobile devices. Based on the consumption value theory, a theoretical model is proposed and empirically examined using survey data from 218 mobile users. The findings demonstrate that contextual offers based on users' profiles, access time, and geographic positions significantly predict their value perceptions (utilitarian, hedonic, and social), which, in turn, affect their intention to use a mobile social reviews platform. This study is also believed to provide some useful insights to both research and practice. PMID:23530548

  11. Recommendations from friends anytime and anywhere: toward a model of contextual offer and consumption values.

    PubMed

    Shen, Xiao-Liang; Sun, Yongqiang; Wang, Nan

    2013-05-01

    The ubiquity and portability of mobile devices provide additional opportunities for information retrieval. People can easily access mobile applications anytime and anywhere when they need to acquire specific context-aware recommendations (contextual offer) from their friends. This study, thus, represents an initial attempt to understand users' acceptance of a mobile-based social reviews platform, where recommendations from friends can be obtained with mobile devices. Based on the consumption value theory, a theoretical model is proposed and empirically examined using survey data from 218 mobile users. The findings demonstrate that contextual offers based on users' profiles, access time, and geographic positions significantly predict their value perceptions (utilitarian, hedonic, and social), which, in turn, affect their intention to use a mobile social reviews platform. This study is also believed to provide some useful insights to both research and practice. PMID:23530548

  12. Evaluation Model of Plate Waste to Monitor Food Consumption in Two Different Catering Settings

    PubMed Central

    Scognamiglio, Umberto; Moroni, Catia; Marani, Alessandra; Calcaterra, Veronica; Amendola, Mariano; Civitelli, Giulia; Cattaruzza, Maria Sofia; Ermenegildi, Arianna; Morena, Valeria

    2014-01-01

    An increasing number of people regularly eats lunch away from home, using catering services. In this context, therefore, it is extremely important to improve the meals’ quality, remaining faithful to the principles of hygiene, nutritional and organoleptic quality and proper food handling. At the same time, it is necessary to promote food choices, nutritionally correct, by evaluations of appropriateness of menus. The study of food waste allows an evaluation of the nutritional habits of consumers and an important economic consideration of the costs incurred for the implementation of the service. This becomes even more important in some particularly sensitive groups, such as children and elderly. The purpose of this work is to test a model of semi-quantitative evaluation of waste to monitor food consumption in two different catering contexts (educational and business), in order to improve the service for school students and other consumers. PMID:27800337

  13. Modeling Heavy/Medium-Duty Fuel Consumption Based on Drive Cycle Properties

    SciTech Connect

    Wang, Lijuan; Duran, Adam; Gonder, Jeffrey; Kelly, Kenneth

    2015-10-13

    This paper presents multiple methods for predicting heavy/medium-duty vehicle fuel consumption based on driving cycle information. A polynomial model, a black box artificial neural net model, a polynomial neural network model, and a multivariate adaptive regression splines (MARS) model were developed and verified using data collected from chassis testing performed on a parcel delivery diesel truck operating over the Heavy Heavy-Duty Diesel Truck (HHDDT), City Suburban Heavy Vehicle Cycle (CSHVC), New York Composite Cycle (NYCC), and hydraulic hybrid vehicle (HHV) drive cycles. Each model was trained using one of four drive cycles as a training cycle and the other three as testing cycles. By comparing the training and testing results, a representative training cycle was chosen and used to further tune each method. HHDDT as the training cycle gave the best predictive results, because HHDDT contains a variety of drive characteristics, such as high speed, acceleration, idling, and deceleration. Among the four model approaches, MARS gave the best predictive performance, with an average absolute percent error of -1.84% over the four chassis dynamometer drive cycles. To further evaluate the accuracy of the predictive models, the approaches were first applied to real-world data. MARS outperformed the other three approaches, providing an average absolute percent error of -2.2% of four real-world road segments. The MARS model performance was then compared to HHDDT, CSHVC, NYCC, and HHV drive cycles with the performance from Future Automotive System Technology Simulator (FASTSim). The results indicated that the MARS method achieved a comparative predictive performance with FASTSim.

  14. Lean consumption.

    PubMed

    Womack, James P; Jones, Daniel T

    2005-03-01

    During the past 20 years, the real price of most consumer goods has fallen worldwide, the variety of goods and the range of sales channels offering them have continued to grow, and product quality has steadily improved. So why is consumption often so frustrating? It doesn't have to be--and shouldn't be--the authors say. They argue that it's time to apply lean thinking to the processes of consumption--to give consumers the full value they want from goods and services with the greatest efficiency and the least pain. Companies may think they save time and money by off-loading work to the consumer but, in fact, the opposite is true. By streamlining their systems for providing goods and services, and by making it easier for customers to buy and use those products and services, a growing number of companies are actually lowering costs while saving everyone time. In the process, these businesses are learning more about their customers, strengthening consumer loyalty, and attracting new customers who are defecting from less user-friendly competitors. The challenge lies with the retailers, service providers, manufacturers, and suppliers that are not used to looking at total cost from the standpoint of the consumer and even less accustomed to working with customers to optimize the consumption process. Lean consumption requires a fundamental shift in the way companies think about the relationship between provision and consumption, and the role their customers play in these processes. It also requires consumers to change the nature of their relationships with the companies they patronize. Lean production has clearly triumphed over similar obstacles in recent years to become the dominant global manufacturing model. Lean consumption, its logical companion, can't be far behind.

  15. Daily Stress and Alcohol Consumption: Modeling Between-Person and Within-Person Ethnic Variation in Coping Behavior*

    PubMed Central

    Aldridge-Gerry, Arianna A.; Roesch, Scott C.; Villodas, Feion; McCabe, Cameron; Leung, Queenie K.; Da Costa, Morgan

    2011-01-01

    Objective: Using a daily diary approach, the current study evaluated the relationship between coping and alcohol consumption using a large, multiethnic sample. The primary goals of this study were to (a) identify coping strategies that are either protective or risk factors for alcohol consumption and (b) model between-ethnic and within-ethnic group variation for these relations. Method: College students (N = 365, 69.0% female) were recruited via flyers, course/club presentations, and university seminars. Participants completed Internet-based daily diaries over the course of 5 days and reported specifically on a target stressful event, how they coped with the stressful event, and the amount of alcohol consumed on a daily level. Results: Use of more avoidance-oriented coping strategies (minimization of stressor, emotional rumination) and social support were significantly associated with more alcohol consumption. Ethnicity, however, did moderate some coping—alcohol associations. Use of religious coping was associated with less alcohol consumption and minimization of the stressor was associated with more alcohol consumption in African Americans; use of social support was associated with more alcohol consumption in Asian Americans; and use of problem-focused coping was associated with less alcohol consumption in Whites. Conclusions: Three maladaptive or risky coping strategies with respect to alcohol consumption were identified using an ecologically valid methodology. However, ethnic-specific variation of these risky (and protective) coping factors was identified. The findings highlight the importance of considering both between-ethnic and within-ethnic group variation with respect to the stress/coping and alcohol consumption. PMID:21138719

  16. Ultrasonic vibration-assisted pelleting of wheat straw: a predictive model for energy consumption using response surface methodology.

    PubMed

    Song, Xiaoxu; Zhang, Meng; Pei, Z J; Wang, Donghai

    2014-01-01

    Cellulosic biomass can be used as a feedstock for biofuel manufacturing. Pelleting of cellulosic biomass can increase its bulk density and thus improve its storability and reduce the feedstock transportation costs. Ultrasonic vibration-assisted (UV-A) pelleting can produce biomass pellets whose density is comparable to that processed by traditional pelleting methods (e.g. extruding, briquetting, and rolling). This study applied response surface methodology to the development of a predictive model for the energy consumption in UV-A pelleting of wheat straw. Effects of pelleting pressure, ultrasonic power, sieve size, and pellet weight were investigated. This study also optimized the process parameters to minimize the energy consumption in UV-A pelleting using response surface methodology. Optimal conditions to minimize the energy consumption were the following: ultrasonic power at 20%, sieve size at 4 mm, and pellet weight at 1g, and the minimum energy consumption was 2.54 Wh. PMID:23859359

  17. Numeric model of the normative consumption of heat for the colour homogenisation of wood in pressure autoclaves

    NASA Astrophysics Data System (ADS)

    Dzurenda, Ladislav

    2016-06-01

    This paper presents a numeric model of the normative consumption of heat for the colour homogenisation of unfrozen wood using saturated steam in pressure autoclaves, in the form of a technically feasible standard. For more effective determination of the objectively necessary consumption of heat for steaming non-frozen wood in a steam autoclave, a program was prepared in EXCEL in the form of a numeric table. Based on the technical and technological data on machinery, the range of colour homogenised wood and the colour-homogenisation regime, the program provides information about normative - the consumption of heat per 1 mł - of colour homogenised wood as well as about the consumption of heat for individual items of the thermal balance off the process of colour homogenisation in a pressure autoclave.

  18. A model to determine the lake nutrient standards for drinking water sources in Yunnan-Guizhou Plateau Ecoregion, China.

    PubMed

    Ji, Danfeng; Xi, Beidou; Su, Jing; Huo, Shouliang; He, Li; Liu, Hongliang; Yang, Queping

    2013-09-01

    Lake eutrophication (LE) has become an increasingly severe environmental problem recently. However, there has been no nutrient standard established for LE control in many developing countries such as China. This study proposes a structural equation model to assist in the establishment of a lake nutrient standard for drinking water sources in Yunnan-Guizhou Plateau Ecoregion (Yungui Ecoregion), China. The modeling results indicate that the most predictive indicator for designated use-attainment is total phosphorus (TP) (total effect = -0.43), and chlorophyll a (Chl-a) is recommended as the second important indicator (total effect = -0.41). The model is further used for estimating the probability of use-attainment associated with lake water as a drinking water source and various levels of candidate criteria (based on the reference conditions and the current environmental quality standards for surface water). It is found that these candidate criteria cannot satisfy the designated 100% use-attainment. To achieve the short-term target (85% attainment of the designated use), TP and Chl-a values ought to be less than 0.02 mg/L and 1.4 microg/L, respectively. When used as a long-term target (90% or greater attainment of the designated use), the TP and Chl-a values are suggested to be less than 0.018 mg/L and 1 microg/L, respectively.

  19. Spatial Differentiation of Arable Land and Permanent Grasslands to Improve a Regional Land Management Model for Nutrient Balancing

    NASA Astrophysics Data System (ADS)

    Gómez Giménez, M.; Della Peruta, R.; de Jong, R.; Keller, A.; Schaepman, M. E.

    2015-12-01

    Agroecosystems play an important role providing economic and ecosystem services, which directly impact society. Inappropriate land use and unsustainable agricultural management with associated nutrient cycles can jeopardize important soil functions such as food production, livestock feeding and conservation of biodiversity. The objective of this study was to integrate remotely sensed land cover information into a regional Land Management Model (LMM) to improve the assessment of spatial explicit nutrient balances for agroecosystems. Remotely sensed data as well as an optimized parameter set contributed to feed the LMM providing a better spatial allocation of agricultural data aggregated at farm level. The integration of land use information in the land allocation process relied predominantly on three factors: i) spatial resolution, ii) classification accuracy and iii) parcels definition. The best-input parameter combination resulted in two different land cover classifications with overall accuracies of 98%, improving the LMM performance by 16% as compared to using non-spatially explicit input. Firstly, the use of spatial explicit information improved the spatial allocation output resulting in a pattern that better followed parcel boundaries (Figure 1). Second, the high classification accuracies ensured consistency between the datasets used. Third, the use of a suitable spatial unit to define the parcels boundaries influenced the model in terms of computational time and the amount of farmland allocated. We conclude that the combined use of remote sensing (RS) data with the LMM has the potential to provide highly accurate information of spatial explicit nutrient balances that are crucial for policy options concerning sustainable management of agricultural soils. Figure 1. Details of the spatial pattern obtained: a) Using only the farm census data, b) using also land use information. Framed in black in the left image (a), examples of artifacts that disappeared when

  20. Dual permeability modeling of tile drain management influences on hydrologic and nutrient transport characteristics in macroporous soil

    NASA Astrophysics Data System (ADS)

    Frey, Steven K.; Hwang, Hyoun-Tae; Park, Young-Jin; Hussain, Syed I.; Gottschall, Natalie; Edwards, Mark; Lapen, David R.

    2016-04-01

    Tile drainage management is considered a beneficial management practice (BMP) for reducing nutrient loads in surface water. In this study, 2-dimensional dual permeability models were developed to simulate flow and transport following liquid swine manure and rhodamine WT (strongly sorbing) tracer application on macroporous clay loam soils under controlled (CD) and free drainage (FD) tile management. Dominant flow and transport characteristics were successfully replicated, including higher and more continuous tile discharge and lower peak rhodamine WT concentrations in FD tile effluent; in relation to CD, where discharge was intermittent, peak rhodamine concentrations higher, and mass exchange from macropores into the soil matrix greater. Explicit representation of preferential flow was essential, as macropores transmitted >98% of surface infiltration, tile flow, and tile solute loads for both FD and CD. Incorporating an active 3rd type lower boundary condition that facilitated groundwater interaction was imperative for simulating CD, as the higher (relative to FD) water table enhanced water and soluble nutrient movement from the soil profile into deeper groundwater. Scenario analysis revealed that in conditions where slight upwards hydraulic gradients exist beneath tiles, groundwater upwelling can influence the concentration of surface derived solutes in tile effluent under FD conditions; whereas the higher and flatter CD water table can restrict groundwater upwelling. Results show that while CD can reduce tile discharge, it can also lead to an increase in surface-application derived nutrient concentrations in tile effluent and hence surface water receptors, and it can promote NO3 loading into groundwater. This study demonstrates dual permeability modeling as a tool for increasing the conceptual understanding of tile drainage BMPs.

  1. Nutrient-induced inflammation in the intestine

    PubMed Central

    Ji, Yong; Sakata, Yasuhisa; Tso, Patrick

    2015-01-01

    Purpose of review To review our current understanding of the relationship between absorption of nutrients and intestinal inflammatory response. Recent findings There is increasing evidence linking gut local inflammatory events with the intake of nutrients. Our recent studies, using the conscious lymph fistula rat model, demonstrate that fat absorption activates the intestinal mucosal mast cells. This is accompanied by a dramatic increase in the lymphatic release of mast cell mediators including histamine, rat mucosal mast cell protease II (RMCPII), as well as the lipid mediator prostaglandin D2 (PGD2). Clinical studies suggest that increased consumption of animal fat may play a role in the pathogenesis of inflammatory bowel disease. This impact of dietary fat may not be restricted to the gut but may extend to the whole body. There is evidence linking a high-fat diet-induced metabolic syndrome, with a low-grade chronic inflammatory state. In this review, we hope to convince the readers that fat absorption can have far reaching physiological and pathophysiological consequences. Summary Understanding the relationship between nutrient absorption and intestinal inflammation is important. We need a better understanding of the interaction between enterocytes and the intestinal immune cells in nutrient absorption and the gut inflammatory responses. PMID:21587069

  2. Determining the best population-level alcohol consumption model and its impact on estimates of alcohol-attributable harms

    PubMed Central

    2012-01-01

    Background The goals of our study are to determine the most appropriate model for alcohol consumption as an exposure for burden of disease, to analyze the effect of the chosen alcohol consumption distribution on the estimation of the alcohol Population- Attributable Fractions (PAFs), and to characterize the chosen alcohol consumption distribution by exploring if there is a global relationship within the distribution. Methods To identify the best model, the Log-Normal, Gamma, and Weibull prevalence distributions were examined using data from 41 surveys from Gender, Alcohol and Culture: An International Study (GENACIS) and from the European Comparative Alcohol Study. To assess the effect of these distributions on the estimated alcohol PAFs, we calculated the alcohol PAF for diabetes, breast cancer, and pancreatitis using the three above-named distributions and using the more traditional approach based on categories. The relationship between the mean and the standard deviation from the Gamma distribution was estimated using data from 851 datasets for 66 countries from GENACIS and from the STEPwise approach to Surveillance from the World Health Organization. Results The Log-Normal distribution provided a poor fit for the survey data, with Gamma and Weibull distributions providing better fits. Additionally, our analyses showed that there were no marked differences for the alcohol PAF estimates based on the Gamma or Weibull distributions compared to PAFs based on categorical alcohol consumption estimates. The standard deviation of the alcohol distribution was highly dependent on the mean, with a unit increase in alcohol consumption associated with a unit increase in the mean of 1.258 (95% CI: 1.223 to 1.293) (R2 = 0.9207) for women and 1.171 (95% CI: 1.144 to 1.197) (R2 = 0. 9474) for men. Conclusions Although the Gamma distribution and the Weibull distribution provided similar results, the Gamma distribution is recommended to model alcohol consumption from population

  3. Combined use of stable isotopes and hydrologic modeling to better understand nutrient sources and cycling in highly altered systems (Invited)

    NASA Astrophysics Data System (ADS)

    Young, M. B.; Kendall, C.; Guerin, M.; Stringfellow, W. T.; Silva, S. R.; Harter, T.; Parker, A.

    2013-12-01

    The Sacramento and San Joaquin Rivers provide the majority of freshwater for the San Francisco Bay Delta. Both rivers are important sources of drinking and irrigation water for California, and play critical roles in the health of California fisheries. Understanding the factors controlling water quality and primary productivity in these rivers and the Delta is essential for making sound economic and environmental water management decisions. However, these highly altered surface water systems present many challenges for water quality monitoring studies due to factors such as multiple potential nutrient and contaminant inputs, dynamic source water inputs, and changing flow regimes controlled by both natural and engineered conditions. The watersheds for both rivers contain areas of intensive agriculture along with many other land uses, and the Sacramento River receives significant amounts of treated wastewater from the large population around the City of Sacramento. We have used a multi-isotope approach combined with mass balance and hydrodynamic modeling in order to better understand the dominant nutrient sources for each of these rivers, and to track nutrient sources and cycling within the complex Delta region around the confluence of the rivers. High nitrate concentrations within the San Joaquin River fuel summer algal blooms, contributing to low dissolved oxygen conditions. High δ15N-NO3 values combined with the high nitrate concentrations suggest that animal manure is a significant source of nitrate to the San Joaquin River. In contrast, the Sacramento River has lower nitrate concentrations but elevated ammonium concentrations from wastewater discharge. Downstream nitrification of the ammonium can be clearly traced using δ15N-NH4. Flow conditions for these rivers and the Delta have strong seasonal and inter-annual variations, resulting in significant changes in nutrient delivery and cycling. Isotopic measurements and estimates of source water contributions

  4. Modelling the 137Cs ingestion dose from consumption of marine fish in Hong Kong.

    PubMed

    Poon, C B; Au, S M

    2002-01-01

    This paper presents a compartmental model for estimating the ingestion dose, due to 137Cs, arising from the consumption of marine fish in Hong Kong. 137Cs is one of the more important radionuclides released in routine liquid effluents discharged from the Guangdong Nuclear Power Station at Daya Bay, which began commercial operation in 1994. In the model, three sea/ocean compartments are considered. Assuming the discharge of this radionuclide is maintained at a constant rate, the model shows that the concentration of 137Cs in the water and in the marine fish in the three sea compartments would become steady after 5 years. The predicted annual dose to an average local individual in Hong Kong, for a release rate of 10 GBq.y(-1), is 3.2 x 10(-5) microSv, which is dominated by the contribution from fish cultured in Hong Kong waters. The cumulative collective dose to the local population of 6 million, at 50 years of discharge, amounts to 9.0 x 10(-3) man.Sv. The annual dose to members of the critical group of local fish farmers does not exceed 3.0 x 10(-3) microSv. All these doses are small compared to the dose of around 1.2 microSv.y(-1) arising from ingestion of naturally occurring radionuclides found in marine fish. Sensitivity of model parameters and uncertainties of prediction are also studied. Difficulties encountered in model validation are discussed. Despite such difficulties. limited field data that are available show that the predicted results are generally within one order of magnitude with measurements.

  5. Pyruvate modifies metabolic flux and nutrient sensing during extracorporeal membrane oxygenation in an immature swine model

    SciTech Connect

    Ledee, Dolena R.; Kajimoto, Masaki; O'Kelly-Priddy, Colleen M.; Olson, Aaron; Isern, Nancy G.; Robillard Frayne, Isabelle; Des Rosiers, Christine; Portman, Michael A.

    2015-07-01

    Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support for infants and children with postoperative cardiopulmonary failure. Nutritional support is mandatory during ECMO, although specific actions for substrates on the heart have not been delineated. Prior work shows that enhancing pyruvate oxidation promotes successful weaning from ECMO. Accordingly, we closely examined the role of prolonged systemic pyruvate supplementation in modifying metabolic parameters during the unique conditions of ventricular unloading provided by ECMO. Twelve male mixed breed Yorkshire piglets (age 30-49 days) received systemic infusion of either normal saline (Group C) or pyruvate (Group P) during ECMO for 8 hours. Over the final hour piglets received [2-13C] pyruvate, and [13C6]-L-leucine, as an indicator for oxidation and protein synthesis. A significant increase in lactate and pyruvate concentrations occurred, along with an increase in the absolute concentration of all measured CAC intermediates. Group P showed greater anaplerotic flux through pyruvate carboxylation although pyruvate oxidation relative to citrate synthase flux was similar to Group C. The groups demonstrated similar leucine fractional contributions to acetyl-CoA and fractional protein synthesis rates. Pyruvate also promoted an increase in the phosphorylation state of several nutrient sensitive enzymes, such as AMPK and ACC, and promoted O-GlcNAcylation through the hexosamine biosynthetic pathway (HBP). In conclusion, prolonged pyruvate supplementation during ECMO modified anaplerotic pyruvate flux and elicited changes in important nutrient and energy sensitive pathways, while preserving protein synthesis. Therefore, the observed results support the further study of nutritional supplementation and its downstream effects on cardiac adaptation during ventricular unloading.

  6. Scaling up food production in the Upper Mississippi river basin: modeling impacts on water quality and nutrient cycling

    NASA Astrophysics Data System (ADS)

    Bowen, E. E.; Martin, P. A.; Schuble, T. J.; Yan, E.; Demissie, Y.

    2010-12-01

    Agricultural production imposes significant environmental stress on the landscape, both in the intensity and extent of agricultural activities. Among the most significant impacts, agriculture dominates the natural reactive nitrogen cycle, with excess reactive nitrogen leading to the degraded quality of inland and coastal waters. In the U.S., policymakers and stakeholders nationwide continue to debate strategies for decreasing environmental degradation from agricultural lands. Such strategies aim to optimize the balance among competing demands for food, fuel and ecosystem services. One such strategy increasingly discussed in the national debate is that of localizing food production around urban areas, developing what some have recently called “foodsheds”. However, the environmental impacts of localizing food production around population centers are not well-understood given the hard-to-generalize variety seen in management practices currently employed among local farms marketing food crops directly to consumers. As a first, landscape level study of potential impacts from scaling up this type of agriculture, we use the USDA Soil and Water Assessment Tool (SWAT) model to quantify environmental impacts from developing foodsheds for all population centers in the Upper Mississippi river basin. Specifically, we focus on nutrient cycling and water quality impacts determining direct greenhouse gas emissions and changes to nutrient runoff from increased food production in this watershed. We investigate a variety of scenarios in which food production is scaled up to the regional level using different types of farm management practices, ranging from conventional production of fruits and vegetables, to production of these products from small-scale, diversified systems integrating conservation easements. In addition to impacts on nutrient cycling and water quality, we also characterize relative levels of productivity in conjunction with overall demand for food associated

  7. Estimating Summer Nutrient Concentrations in Northeastern Lakes from SPARROW Load Predictions and Modeled Lake Depth and Volume

    EPA Science Inventory

    Global nutrient cycles have been altered by use of fossil fuels and fertilizers resulting in increases in nutrient loads to aquatic systems. In the United States, excess nutrients have been repeatedly reported as the primary cause of lake water quality impairments. Setting nutr...

  8. Modeling oxygen consumption in the proximal tubule: effects of NHE and SGLT2 inhibition.

    PubMed

    Layton, Anita T; Vallon, Volker; Edwards, Aurélie

    2015-06-15

    The objective of this study was to investigate how physiological, pharmacological, and pathological conditions that alter sodium reabsorption (TNa) in the proximal tubule affect oxygen consumption (QO2 ) and Na(+) transport efficiency (TNa/QO2 ). To do so, we expanded a mathematical model of solute transport in the proximal tubule of the rat kidney. The model represents compliant S1, S2, and S3 segments and accounts for their specific apical and basolateral transporters. Sodium is reabsorbed transcellularly, via apical Na(+)/H(+) exchangers (NHE) and Na(+)-glucose (SGLT) cotransporters, and paracellularly. Our results suggest that TNa/QO2 is 80% higher in S3 than in S1-S2 segments, due to the greater contribution of the passive paracellular pathway to TNa in the former segment. Inhibition of NHE or Na-K-ATPase reduced TNa and QO2 , as well as Na(+) transport efficiency. SGLT2 inhibition also reduced proximal tubular TNa but increased QO2 ; these effects were relatively more pronounced in the S3 vs. the S1-S2 segments. Diabetes increased TNa and QO2 and reduced TNa/QO2 , owing mostly to hyperfiltration. Since SGLT2 inhibition lowers diabetic hyperfiltration, the net effect on TNa, QO2 , and Na(+) transport efficiency in the proximal tubule will largely depend on the individual extent to which glomerular filtration rate is lowered.

  9. Modeling oxygen consumption in the proximal tubule: effects of NHE and SGLT2 inhibition

    PubMed Central

    Vallon, Volker; Edwards, Aurélie

    2015-01-01

    The objective of this study was to investigate how physiological, pharmacological, and pathological conditions that alter sodium reabsorption (TNa) in the proximal tubule affect oxygen consumption (QO2) and Na+ transport efficiency (TNa/QO2). To do so, we expanded a mathematical model of solute transport in the proximal tubule of the rat kidney. The model represents compliant S1, S2, and S3 segments and accounts for their specific apical and basolateral transporters. Sodium is reabsorbed transcellularly, via apical Na+/H+ exchangers (NHE) and Na+-glucose (SGLT) cotransporters, and paracellularly. Our results suggest that TNa/QO2 is 80% higher in S3 than in S1–S2 segments, due to the greater contribution of the passive paracellular pathway to TNa in the former segment. Inhibition of NHE or Na-K-ATPase reduced TNa and QO2, as well as Na+ transport efficiency. SGLT2 inhibition also reduced proximal tubular TNa but increased QO2; these effects were relatively more pronounced in the S3 vs. the S1–S2 segments. Diabetes increased TNa and QO2 and reduced TNa/QO2, owing mostly to hyperfiltration. Since SGLT2 inhibition lowers diabetic hyperfiltration, the net effect on TNa, QO2, and Na+ transport efficiency in the proximal tubule will largely depend on the individual extent to which glomerular filtration rate is lowered. PMID:25855513

  10. Numerical solution of a conspicuous consumption model with constant control delay☆

    PubMed Central

    Huschto, Tony; Feichtinger, Gustav; Hartl, Richard F.; Kort, Peter M.; Sager, Sebastian; Seidl, Andrea

    2011-01-01

    We derive optimal pricing strategies for conspicuous consumption products in periods of recession. To that end, we formulate and investigate a two-stage economic optimal control problem that takes uncertainty of the recession period length and delay effects of the pricing strategy into account. This non-standard optimal control problem is difficult to solve analytically, and solutions depend on the variable model parameters. Therefore, we use a numerical result-driven approach. We propose a structure-exploiting direct method for optimal control to solve this challenging optimization problem. In particular, we discretize the uncertainties in the model formulation by using scenario trees and target the control delays by introduction of slack control functions. Numerical results illustrate the validity of our approach and show the impact of uncertainties and delay effects on optimal economic strategies. During the recession, delayed optimal prices are higher than the non-delayed ones. In the normal economic period, however, this effect is reversed and optimal prices with a delayed impact are smaller compared to the non-delayed case. PMID:22267871

  11. HPC Server Performance and Power Consumption for Atmospheric Modeling on GPUs Configured with Different CPU Platforms

    NASA Astrophysics Data System (ADS)

    Posey, Stan; Messmer, Peter; Appleyard, Jeremy

    2015-04-01

    Current trends in high performance computing (HPC) are moving towards the use of graphics processing units (GPUs) to achieve speedups through the extraction of fine-grain parallelism of application software. GPUs have been developed exclusively for computational tasks as massively-parallel co-processors to the CPU, and during 2014 the latest NVIDIA GPU architecture can operate with as many as three CPU platforms. In addition to the conventional use of the x86 CPU architecture with GPUs starting from the mid-2000's, the POWER and ARM-64 architectures have recently become available as x86 alternatives. Today computational efficiency and increased performance per energy-cost are key drivers behind HPC decisions to implement GPU-based servers for atmospheric modeling. The choice of a server CPU platform will influence performance and overall power consumption of a system, and also the available configurations of CPU-to-GPU ratio. It follows that such system design configurations continue to be a critical factor behind scientific decisions to implement models at higher resolutions and possibly with an increased use of ensembles. This presentation will examine the current state of GPU developments for atmospheric modeling with examples from the COSMO dycore and from various WRF physics, and for different CPU platforms. The examples provided will be relevant to science-scale HPC practice of CPU-GPU system configurations based on model resolution requirements of a particular simulation. Performance results will compare use of the latest available CPUs from the three available CPU architectures, both with and without GPU acceleration. Finally a GPU outlook is provided on GPU hardware, software, tools, and programmability for each of the available CPU platforms.

  12. Nutrient density: principles and evaluation tools.

    PubMed

    Drewnowski, Adam; Fulgoni, Victor L

    2014-05-01

    Nutrient profiling is the technique of rating or classifying foods on the basis of their nutritional value. Foods that supply relatively more nutrients than calories are defined as nutrient dense. Nutrient profile models calculate the content of key nutrients per 100 g, 100 kcal, or per serving size of food. For maximum effectiveness, nutrient profile models need to be transparent, based on publicly accessible nutrient composition data, and validated against independent measures of a healthy diet. These rigorous scientific standards were applied to the development of the Nutrient-Rich Foods (NRF) family of nutrient profile models. First, the NRF models included nutrients to encourage as well as nutrients to limit. Second, NRF model performance was repeatedly tested against the Healthy Eating Index (HEI), an independent measure of a healthy diet. HEI values were calculated for participants in the 1999-2002 NHANES. Models based on 100 kcal and serving sizes performed better than those based on 100 g. Formulas based on sums and means performed better than those based on ratios. The final NRF9.3 index was based on 9 beneficial nutrients (protein; fiber; vitamins A, C, and E; calcium; iron; potassium; and magnesium) and on 3 nutrients to limit (saturated fat, added sugar, and sodium). Higher NRF9.3 scores were associated with lower energy density and more nutrient-rich diets. The nutrient density of foods, paired with a comprehensive program of consumer education, can become the foundation of dietary recommendations and guidelines.

  13. Life cycle assessment of vehicle lightweighting: a physics-based model of mass-induced fuel consumption.

    PubMed

    Kim, Hyung Chul; Wallington, Timothy J

    2013-12-17

    Lightweighting is a key strategy used to improve vehicle fuel economy. Replacing conventional materials (e.g., steel) with lighter alternatives (e.g., aluminum, magnesium, and composites) decreases energy consumption and greenhouse gas (GHG) emissions during vehicle use, but often increases energy consumption and GHG emissions during materials and vehicle production. Assessing the life-cycle benefits of mass reduction requires a quantitative description of the mass-induced fuel consumption during vehicle use. A new physics-based method for estimating mass-induced fuel consumption (MIF) is proposed. We illustrate the utility of this method by using publicly available data to calculate MIF values in the range of 0.2-0.5 L/(100 km 100 kg) based on 106 records of fuel economy tests by the U.S. Environmental Protection Agency for 2013 model year vehicles. Lightweighting is shown to have the most benefit when applied to vehicles with high fuel consumption and high power. Use of the physics-based model presented here would place future life cycle assessment studies of vehicle lightweighting on a firmer scientific foundation.

  14. Fishing for nutrients in heterogeneous landscapes: modelling plant growth trade-offs in monocultures and mixed communities

    PubMed Central

    Croft, Simon Antony; Pitchford, Jonathan W.; Hodge, Angela

    2015-01-01

    The problem of how best to find and exploit essential resources, the quality and locations of which are unknown, is common throughout biology. For plants, the need to grow an efficient root system so as to acquire patchily distributed soil nutrients is typically complicated by competition between plants, and by the costs of maintaining the root system. Simple mechanistic models for root growth can help elucidate these complications, and here we argue that these models can be usefully informed by models initially developed for foraging fish larvae. Both plant and fish need to efficiently search a spatio-temporally variable environment using simple algorithms involving only local information, and both must perform this task against a backdrop of intra- and inter-specific competition and background mortality. Here we develop these parallels by using simple stochastic models describing the growth and efficiency of four contrasting idealized root growth strategies. We show that plants which grow identically in isolation in homogeneous substrates will typically perform very differently when grown in monocultures, in heterogeneous nutrient landscapes and in mixed-species competition. In particular, our simulations show a consistent result that plants which trade-off rapid growth in favour of a more efficient and durable root system perform better, both on average and in terms of the best performing individuals, than more rapidly growing ephemeral root systems. Moreover, when such slower growing but more efficient plants are grown in competition, the overall community productivity can exceed that of the constituent monocultures. These findings help to disentangle many of the context-dependent behaviours seen in the experimental literature, and may form a basis for future studies at the level of complex population dynamics and life history evolution. PMID:26371292

  15. Variations in source apportionments of nutrient load among seasons and hydrological years in a semi-arid watershed: GWLF model results.

    PubMed

    Du, Xinzhong; Li, Xuyong; Zhang, Wangshou; Wang, Huiliang

    2014-05-01

    Quantifying source apportionments of nutrient load and their variations among seasons and hydrological years can provide useful information for watershed nutrient load reduction programs. There are large seasonal and inter-annual variations in nutrient loads and their sources in semi-arid watersheds that have a monsoon climate. The Generalized Watershed Loading Function model was used to simulate monthly nutrient loads from 2004 to 2011 in the Liu River watershed, Northern China. Model results were used to investigate nutrient load contributions from different sources, temporal variations of source apportionments and the differences in the behavior of total nitrogen (TN) and total phosphorus (TP). Examination of source apportionments for different seasons showed that point sources were the main source of TN and TP in the non-flood season, whereas contributions from diffuse sources, such as rural runoff, soil erosion, and urban areas, were much higher in the flood season. Furthermore, results for three typical hydrological years showed that the contribution ratios of nutrient loads from point sources increased as streamflow decreased, while contribution ratios from rural runoff and urban area increased as streamflow increased. Further, there were significant differences between TN and TP sources on different time scales. Our findings suggest that priority actions and management measures should be changed for different time periods and hydrological conditions, and that different strategies should be used to reduce loads of nitrogen and phosphorus effectively.

  16. A review of sediment and nutrient concentration data from Australia for use in catchment water quality models.

    PubMed

    Bartley, Rebecca; Speirs, William J; Ellis, Tim W; Waters, David K

    2012-01-01

    Land use (and land management) change is seen as the primary factor responsible for changes in sediment and nutrient delivery to water bodies. Understanding how sediment and nutrient (or constituent) concentrations vary with land use is critical to understanding the current and future impact of land use change on aquatic ecosystems. Access to appropriate land-use based water quality data is also important for calculating reliable load estimates using water quality models. This study collated published and unpublished runoff, constituent concentration and load data for Australian catchments. Water quality data for total suspended sediments (TSS), total nitrogen (TN) and total phosphorus (TP) were collated from runoff events with a focus on catchment areas that have a single or majority of the contributing area under one land use. Where possible, information on the dissolved forms of nutrients were also collated. For each data point, information was included on the site location, land use type and condition, contributing catchment area, runoff, laboratory analyses, the number of samples collected over the hydrograph and the mean constituent concentration calculation method. A total of ∼750 entries were recorded from 514 different geographical sites covering 13 different land uses. We found that the nutrient concentrations collected using "grab" sampling (without a well defined hydrograph) were lower than for sites with gauged auto-samplers although this data set was small and no statistical analysis could be undertaken. There was no statistically significant difference (p<0.05) between data collected at plot and catchment scales for the same land use. This is most likely due to differences in land condition over-shadowing the effects of spatial scale. There was, however, a significant difference in the concentration value for constituent samples collected from sites where >90% of the catchment was represented by a single land use, compared to sites with <90% of the

  17. A review of sediment and nutrient concentration data from Australia for use in catchment water quality models.

    PubMed

    Bartley, Rebecca; Speirs, William J; Ellis, Tim W; Waters, David K

    2012-01-01

    Land use (and land management) change is seen as the primary factor responsible for changes in sediment and nutrient delivery to water bodies. Understanding how sediment and nutrient (or constituent) concentrations vary with land use is critical to understanding the current and future impact of land use change on aquatic ecosystems. Access to appropriate land-use based water quality data is also important for calculating reliable load estimates using water quality models. This study collated published and unpublished runoff, constituent concentration and load data for Australian catchments. Water quality data for total suspended sediments (TSS), total nitrogen (TN) and total phosphorus (TP) were collated from runoff events with a focus on catchment areas that have a single or majority of the contributing area under one land use. Where possible, information on the dissolved forms of nutrients were also collated. For each data point, information was included on the site location, land use type and condition, contributing catchment area, runoff, laboratory analyses, the number of samples collected over the hydrograph and the mean constituent concentration calculation method. A total of ∼750 entries were recorded from 514 different geographical sites covering 13 different land uses. We found that the nutrient concentrations collected using "grab" sampling (without a well defined hydrograph) were lower than for sites with gauged auto-samplers although this data set was small and no statistical analysis could be undertaken. There was no statistically significant difference (p<0.05) between data collected at plot and catchment scales for the same land use. This is most likely due to differences in land condition over-shadowing the effects of spatial scale. There was, however, a significant difference in the concentration value for constituent samples collected from sites where >90% of the catchment was represented by a single land use, compared to sites with <90% of the

  18. Key Nutrients.

    ERIC Educational Resources Information Center

    Federal Extension Service (USDA), Washington, DC.

    Lessons written to help trainer agents prepare aides for work with families in the Food and Nutrition Program are presented in this booklet. The key nutrients discussed in the 10 lessons are protein, carbohydrates, fat, calcium, iron, iodine, and Vitamins A, B, C, and D. the format of each lesson is as follows: Purpose, Presentation, Application…

  19. The Regionalization of National-Scale SPARROW Models for Stream Nutrients

    USGS Publications Warehouse

    Schwarz, G.E.; Alexander, R.B.; Smith, R.A.; Preston, S.D.

    2011-01-01

    This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national-scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard errors in the prediction of TN and TP loads, expressed as a percentage of the predicted load, by about 6 and 7%. We develop and apply a method for combining national-scale and regional-scale information to estimate a hybrid model that imposes cross-region constraints that limit regional variation in model coefficients, effectively reducing the number of free model parameters as compared to a collection of independent regional models. The hybrid TN and TP regional models have improved model fit relative to the respective national models, reducing the standard error in the prediction of loads, expressed as a percentage of load, by about 5 and 4%. Only 19% of the TN hybrid model coefficients and just 2% of the TP hybrid model coefficients show evidence of substantial regional specificity (more than ??100% deviation from the national model estimate). The hybrid models have much greater precision in the estimated coefficients than do the unconstrained regional models, demonstrating the efficacy of pooling information across regions to improve regional models. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  20. Modeling Household Water Consumption in a Hydro-Institutional System - The Case of Jordan

    NASA Astrophysics Data System (ADS)

    Klassert, C. J. A.; Gawel, E.; Klauer, B.; Sigel, K.

    2014-12-01

    Jordan faces an archetypal combination of high water scarcity, with a per capita water availability of around 150 CM per year significantly below the absolute scarcity threshold of 500 CM, and strong population growth, especially due to the Syrian refugee crisis. This poses a severe challenge to the already strained institutions in the Jordanian water sector. The Stanford-led G8 Belmont Forum project "Integrated Analysis of Freshwater Resources Sustainability in Jordan" aims at analyzing the potential role of water sector institutions in the pursuit of a sustainable freshwater system performance. In order to do so, the project develops a coupled hydrological and agent-based model, allowing for the exploration of physical as well as socio-economic and institutional scenarios for Jordan's water sector. The part of this integrated model in focus here is the representation of household behavior in Jordan's densely populated capital Amman. Amman's piped water supply is highly intermittent, which also affects its potability. Therefore, Amman's citizens rely on various decentralized modes of supply, depending on their socio-economic characteristics. These include water storage in roof-top and basement tanks, private tanker supply, and the purchase of bottled water. Capturing this combination of centralized and decentralized supply modes is important for an adequate representation of water consumption behavior: Firstly, it will affect the impacts of supply-side and demand-side policies, such as reductions of non-revenue water (including illegal abstractions), the introduction of continuous supply, support for storage enhancements, and water tariff reforms. Secondly, it is also necessary to differentiate the impacts of any policy on the different socio-economic groups in Amman. In order to capture the above aspects of water supply, our model is based on the tiered supply curve approach, developed by Srinivasan et al. in 2011 to model a similar situation in Chennai, India

  1. Using models to guide field experiments: a priori predictions for the CO2 response of a nutrient- and water-limited native Eucalypt woodland.

    PubMed

    Medlyn, Belinda E; De Kauwe, Martin G; Zaehle, Sönke; Walker, Anthony P; Duursma, Remko A; Luus, Kristina; Mishurov, Mikhail; Pak, Bernard; Smith, Benjamin; Wang, Ying-Ping; Yang, Xiaojuan; Crous, Kristine Y; Drake, John E; Gimeno, Teresa E; Macdonald, Catriona A; Norby, Richard J; Power, Sally A; Tjoelker, Mark G; Ellsworth, David S

    2016-08-01

    The response of terrestrial ecosystems to rising atmospheric CO2 concentration (Ca ), particularly under nutrient-limited conditions, is a major uncertainty in Earth System models. The Eucalyptus Free-Air CO2 Enrichment (EucFACE) experiment, recently established in a nutrient- and water-limited woodland presents a unique opportunity to address this uncertainty, but can best do so if key model uncertainties have been identified in advance. We applied seven vegetation models, which have previously been comprehensively assessed against earlier forest FACE experiments, to simulate a priori possible outcomes from EucFACE. Our goals were to provide quantitative projections against which to evaluate data as they are collected, and to identify key measurements that should be made in the experiment to allow discrimination among alternative model assumptions in a postexperiment model intercomparison. Simulated responses of annual net primary productivity (NPP) to elevated Ca ranged from 0.5 to 25% across models. The simulated reduction of NPP during a low-rainfall year also varied widely, from 24 to 70%. Key processes where assumptions caused disagreement among models included nutrient limitations to growth; feedbacks to nutrient uptake; autotrophic respiration; and the impact of low soil moisture availability on plant processes. Knowledge of the causes of variation among models is now guiding data collection in the experiment, with the expectation that the experimental data can optimally inform future model improvements. PMID:26946185

  2. Adaptive function of soil consumption: an in vitro study modeling the human stomach and small intestine.

    PubMed

    Dominy, Nathaniel J; Davoust, Estelle; Minekus, Mans

    2004-01-01

    Despite occurring in a wide variety of taxa, deliberate soil consumption (geophagy) is a poorly understood behavior. In humans, geophagy is sometimes considered aberrant or a sign of metabolic dysfunction. However, geophagy is normally assigned an adaptive function in nonhuman primates and various other organisms. One hypothesis submits that clay-rich soil adsorbs intestinal insults, namely plant metabolites or diarrhoea-causing enterotoxins. Here we test the capacity of kaolin, a commonly ingested clay, to adsorb quinine (an alkaloid) and two types of tannin (digestion-inhibitors). Trials were conducted in vitro using the TNO Intestinal Model, a device that closely simulates digestion by the human stomach and small intestine. Kaolin reduced the bioavailability of each compound by < or =30%. However, because we could not replicate clay-epithelial adhesion and reduced motility, these results may underestimate adsorption in vivo. We also show that kaolin fails to render calcium oxalate soluble. We conclude that gastrointestinal adsorption is the most plausible function of human geophagy. Adaptive advantages include greater exploitation of marginal plant foods and reduced energetic costs of diarrhoea, factors that could account for the high frequency of geophagy in children and pregnant women across the tropics.

  3. Evaluation of fuel consumption potential of medium and heavy duty vehicles through modeling and simulation.

    SciTech Connect

    Delorme, A.; Karbowski, D.; Sharer, P.; Energy Systems

    2010-03-31

    The main objective of this report is to provide quantitative data to support the Committee in its task of establishing a report to support rulemaking on medium- and heavy-duty fuel efficiency improvement. In particular, it is of paramount importance for the Committee to base or illustrate their conclusions on established models and actual state-of-the art data. The simulations studies presented in the report have been defined and requested by the members of the National Academy committee to provide quantitative inputs to support their recommendations. As such, various technologies and usage scenarios were considered for several applications. One of the objective is to provide the results along with their associated assumptions (both vehicle and drive cycles), information generally missing from public discussions on literature search. Finally, the advantages and limitations of using simulation will be summarized. The study addresses several of the committee tasks, including: (1) Discussion of the implication of metric selection; (2) Assessing the impact of existing technologies on fuel consumption through energy balance analysis (both steady-state and standard cycles) as well as real world drive cycles; and (3) Impact of future technologies, both individually and collectively.

  4. Predictive model for chloroform during disinfection of water for consumption, city of Montevideo.

    PubMed

    Gomez Camponovo, Mariana; Seoane Muniz, Gustavo; Rothenberg, Stephen J; Umpiérrez Vazquez, Eleuterio; Achkar Borras, Marcel

    2014-10-01

    The objective of this study was to predict chloroform formation resulting from the process of disinfecting water, particularly trihalomethane which is most frequently produced. A statistical model was used which included repeated measurements of water parameters used for monitoring water quality at 51 sites covering the municipal water system of Montevideo. Samples were taken considering different seasons from June 2009 to July 2011 in Montevideo. Total samples (n = 330) were analytically studied using the headspace-gas chromatography method coupled with mass spectrometry. Chloroform was the dependent variable and the covariables were pH, temperature, free chlorine, and total chlorine. A Tobit analysis with an unstructured correlation matrix was performed, and a significant interaction was found between pH and free chlorine for the prediction of chloroform formation. We concluded that parameters for the continuous control of water quality for consumption can be used to predict the levels of chloroform that may be present. Given the large measurement to variability found in the repeated measurements, the use of averages that include more than one season is not recommended to determine the degree of compliance with acceptable levels established by norms. PMID:24981876

  5. [The effects of manpower emigration on income distribution and consumption models in the Egyptian economy].

    PubMed

    Abdel Fadil, M

    1985-01-01

    This work analyzes the effects of emigration from Egypt on the distribution of income and the consumption model of the Egyptian economy. The increasing role of remittances as a principal source of household income has disturbed the old division of income among socioeconomic groups. It is difficult to estimate the volume of remittances with any precision because of the variety of ways in which they can be made. Official statistics tend to underestimate their value by ignoring black market transactions, remittances of merchandise, and other forms. An estimate was made of the value of remittances in 1980 taking account of wage levels of 5 different types of workers in the principal employing countries, their average propensities to save, and the employment structure of migrants by socioprofessional groups. The average educational level of emigrants appears to have declined somewhat between 1972-78. Average monthly income for emigrants was estimated to range from 792 Egyptian pounds for technical and professional workers to 252 for unskilled workers and the propensity to save was estimated to range from 40% for technical and scientific workers to 15% for unskilled workers. The total income remitted in 1980 in millions of Egyptian pounds was estimated at 912 for 240,000 technical and scienfific workers, 739 for 360,000 intermediate level workers, 415 for 300,000 artisans and workers, 60 for 60,000 chauffeurs, and 109 for 240,000 unskilled workers. Although remittances have elevated the per capita income of the low income groups, their impact has been diminished by severe inflationary pressures which have led to a decline in living levels and a less complete satisfaction of basic needs. Salary levels of construction workers were 7-9 times higher in Egyptian pounds in 1977 in 3 countries of immigration than in Egypt, while they were 7-10 times higher in 4 countries for university professors. Remittances are used by families receiving them for subsistence or investment

  6. MODELING THE IMPACTS OF DECADAL CHANGES IN RIVERINE NUTRIENT FLUXES ON COASTAL EUTROPHICATION NEAR THE MISSISSIPPI RIVER DELTA. (R827785E02)

    EPA Science Inventory

    A mathematical model was used to link decadal changes in the Mississippi River nutrient flux to coastal eutrophication near the Mississippi River Delta. Model simulations suggest that bottom water hypoxia intensified about 30 years ago, as a probable consequence of increased n...

  7. Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

    PubMed

    Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

    2010-08-01

    Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (p<0.001) higher removal of nitrate was observed in the biphasic (42-63%) compared to the monophasic rain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (p<0.001), achieving up to 87% removal at a treatment C/N ratio of 2.0. This study demonstrates the importance of retention time, environmental conditions (i.e. saturated/unsaturated conditions), and availability of C substrate for bioremediation of pollutants, especially nitrates, in rain gardens.

  8. Modeling and CFD simulation of nutrient distribution in picoliter bioreactors for bacterial growth studies on single-cell level.

    PubMed

    Westerwalbesloh, Christoph; Grünberger, Alexander; Stute, Birgit; Weber, Sophie; Wiechert, Wolfgang; Kohlheyer, Dietrich; von Lieres, Eric

    2015-11-01

    A microfluidic device for microbial single-cell cultivation of bacteria was modeled and simulated using COMSOL Multiphysics. The liquid velocity field and the mass transfer within the supply channels and cultivation chambers were calculated to gain insight in the distribution of supplied nutrients and metabolic products secreted by the cultivated bacteria. The goal was to identify potential substrate limitations or product accumulations within the cultivation device. The metabolic uptake and production rates, colony size, and growth medium composition were varied covering a wide range of operating conditions. Simulations with glucose as substrate did not show limitations within the typically used concentration range, but for alternative substrates limitations could not be ruled out. This lays the foundation for further studies and the optimization of existing picoliter bioreactor systems.

  9. Drugs, nutrients, and phytoactive principles improving the health span of rodent models of human age-related diseases.

    PubMed

    Lebel, Michel; Picard, Frédéric; Ferland, Guylaine; Gaudreau, Pierrette

    2012-02-01

    Rodents are often the species of choice to examine the effect of drugs on survival and on the progression of specific diseased tissues. This statement is also true for research laboratories working in the field of nutrition and aging. In addition to diets that can reduce the life expectancy of rodents, such as diabetogenic or high-fat diets, genetically modified rodents exhibiting different accelerated age-associated diseases also provide important biologic tools to decipher the impact of drugs, nutrients, or phytoactive compounds on their health and life span. This review covers some of the chemicals believed to decelerate the appearance of age-related diseases in different rodent models. Such chemicals include antioxidants, anti-inflammatory molecules, modulators of metabolic sensors, calorie restriction mimetics, and vegetal polyphenolic compounds that affect mitochondrial functions, cellular proliferation or differentiation as well as cell functionality.

  10. Modeling and CFD simulation of nutrient distribution in picoliter bioreactors for bacterial growth studies on single-cell level.

    PubMed

    Westerwalbesloh, Christoph; Grünberger, Alexander; Stute, Birgit; Weber, Sophie; Wiechert, Wolfgang; Kohlheyer, Dietrich; von Lieres, Eric

    2015-11-01

    A microfluidic device for microbial single-cell cultivation of bacteria was modeled and simulated using COMSOL Multiphysics. The liquid velocity field and the mass transfer within the supply channels and cultivation chambers were calculated to gain insight in the distribution of supplied nutrients and metabolic products secreted by the cultivated bacteria. The goal was to identify potential substrate limitations or product accumulations within the cultivation device. The metabolic uptake and production rates, colony size, and growth medium composition were varied covering a wide range of operating conditions. Simulations with glucose as substrate did not show limitations within the typically used concentration range, but for alternative substrates limitations could not be ruled out. This lays the foundation for further studies and the optimization of existing picoliter bioreactor systems. PMID:26345659

  11. Ruminal Degradability and Summative Models Evaluation for Total Digestible Nutrients Prediction of Some Forages and Byproducts in Goats

    PubMed Central

    López, Rafael

    2013-01-01

    In in vitro true dry matter degradability (IVTDMD), in situ dry matter degradability, and neutral detergent fiber degradability, both in vitro (IVNDFD) and in situ (ISNDFD) techniques were used with crossbred goats to determine dry matter and neutral detergent fiber (NDF) ruminal degradability in eight forages and four industrial byproducts. Total digestible nutrients (TDN) content obtained with five different summative models (summative equations) were studied to compare the precision of estimates. All these models included digestible fractions of crude protein, ether extract, and nonfiber carbohydrates that were calculated from chemical composition, but digestible NDF (dNDF) was obtained from IVNDFD (IVdNDF), ISNDFD (ISdNDF), or by using the Surface Law approach. On the basis of the coefficient of determination (R2) of the simple lineal regression of predicted TDN (y-axes) and observed IVTDMD (x-axes), the precision of models was tested. The predicted TDN by the National Research Council model exclusively based on chemical composition only explains up to 41% of observed IVTDMD values, whereas the model based on IVdNDF had a high precision (96%) to predict TDN from forage and byproducts fiber when used in goats. PMID:23762592

  12. Modeling study of the influence of mixing on the fluxes of nutrients through the water column redox-interfaces

    NASA Astrophysics Data System (ADS)

    Yakushev, E.

    2009-04-01

    In this study we used a coupled hydrophysical-biogeochemical O-N-S-P-Mn-Fe- model based on ROLM (Yakushev et al., 2007) and GOTM (Burchard et al., 2006). Processes of organic matter (OM) formation and decay, the reduction and oxidation of species of nitrogen, sulphur, manganese, iron, as well as transformation of phosphorus species are parameterized. The model considered phytoplankton, zooplankton and bacteria. The model allowed to simulate the main features of the vertically balanced biogeochemical structure of the redox interfaces (i.e observed in the Black Sea, Gotland Deep, Oslo Fjord). Numerical experiments allowed to demonstrate how the changes in vertical mixing (from Kz=10-6 m2s-1 to Kz=10-4 m2s-1) affect the distributions of the considered parameters and the rates of their transformation. The received estimates allowed to analyze the influence of the water column redox interfaces on the fluxes of nutrients, in particular phosphate, in different conditions. Burchard, H., Bolding, K., Kuehn, W., Meister, A., Neumann, T., Umlauf, L. 2006. Description of a flexible and extendable physical-biogeochemical model system for the water column. J.of Mar.Sys., 61: 180-211. Yakushev E.V., Pollehne F., Jost G. et al. 2007. Analysis of the water column oxic/anoxic interface in the Black and Baltic seas with a Redox-Layer Model. Mar. Chem., 107: 388-410.

  13. A modified exponential behavioral economic demand model to better describe consumption data.

    PubMed

    Koffarnus, Mikhail N; Franck, Christopher T; Stein, Jeffrey S; Bickel, Warren K

    2015-12-01

    Behavioral economic demand analyses that quantify the relationship between the consumption of a commodity and its price have proven useful in studying the reinforcing efficacy of many commodities, including drugs of abuse. An exponential equation proposed by Hursh and Silberberg (2008) has proven useful in quantifying the dissociable components of demand intensity and demand elasticity, but is limited as an analysis technique by the inability to correctly analyze consumption values of zero. We examined an exponentiated version of this equation that retains all the beneficial features of the original Hursh and Silberberg equation, but can accommodate consumption values of zero and improves its fit to the data. In Experiment 1, we compared the modified equation with the unmodified equation under different treatments of zero values in cigarette consumption data collected online from 272 participants. We found that the unmodified equation produces different results depending on how zeros are treated, while the exponentiated version incorporates zeros into the analysis, accounts for more variance, and is better able to estimate actual unconstrained consumption as reported by participants. In Experiment 2, we simulated 1,000 datasets with demand parameters known a priori and compared the equation fits. Results indicated that the exponentiated equation was better able to replicate the true values from which the test data were simulated. We conclude that an exponentiated version of the Hursh and Silberberg equation provides better fits to the data, is able to fit all consumption values including zero, and more accurately produces true parameter values. PMID:26280591

  14. Nonhuman primate model of alcohol abuse: effects of early experience, personality, and stress on alcohol consumption.

    PubMed Central

    Higley, J D; Hasert, M F; Suomi, S J; Linnoila, M

    1991-01-01

    Twenty-two 50-month-old rhesus monkeys were provided concurrent free access to an aspartame-sweetened 7% ethanol solution and an aspartame-sweetened vehicle before, during, and after social separation. Subjects had been reared for their first 6 months of life either without access to adults but with constant access to age mates (peer reared), a condition producing reduced exploration and increased fear-related behaviors, or as controls with their mothers; thereafter, all subjects received identical treatment. During home-cage periods, for 1 hr each day, 4 days a week, when the ethanol solution and vehicle were freely available, peer-reared subjects consumed significantly more alcohol than mother-reared subjects. When stress was increased via social separation, mother-reared animals increased their alcohol consumption to a level nearly as high as that of peer-reared monkeys. Average individual differences in alcohol consumption were markedly stable over time. In addition, there were strong positive correlations between alcohol consumption and distress behaviors. Biological indices of increased stress, such as plasma cortisol and corticotropin, were higher in peer-reared subjects. Within the peer- and mother-reared groups, these indices were positively correlated with alcohol consumption. The results suggest that early rearing experiences that predispose monkeys to increased fear-related behaviors produce excessive alcohol consumption under normal living conditions. Furthermore, a major challenge such as social separation increases alcohol consumption to levels producing intoxication even in monkeys not particularly vulnerable to stress. Images PMID:1871131

  15. Nonhuman primate model of alcohol abuse: effects of early experience, personality, and stress on alcohol consumption.

    PubMed

    Higley, J D; Hasert, M F; Suomi, S J; Linnoila, M

    1991-08-15

    Twenty-two 50-month-old rhesus monkeys were provided concurrent free access to an aspartame-sweetened 7% ethanol solution and an aspartame-sweetened vehicle before, during, and after social separation. Subjects had been reared for their first 6 months of life either without access to adults but with constant access to age mates (peer reared), a condition producing reduced exploration and increased fear-related behaviors, or as controls with their mothers; thereafter, all subjects received identical treatment. During home-cage periods, for 1 hr each day, 4 days a week, when the ethanol solution and vehicle were freely available, peer-reared subjects consumed significantly more alcohol than mother-reared subjects. When stress was increased via social separation, mother-reared animals increased their alcohol consumption to a level nearly as high as that of peer-reared monkeys. Average individual differences in alcohol consumption were markedly stable over time. In addition, there were strong positive correlations between alcohol consumption and distress behaviors. Biological indices of increased stress, such as plasma cortisol and corticotropin, were higher in peer-reared subjects. Within the peer- and mother-reared groups, these indices were positively correlated with alcohol consumption. The results suggest that early rearing experiences that predispose monkeys to increased fear-related behaviors produce excessive alcohol consumption under normal living conditions. Furthermore, a major challenge such as social separation increases alcohol consumption to levels producing intoxication even in monkeys not particularly vulnerable to stress.

  16. Development of urban water consumption models for the City of Los Angeles

    NASA Astrophysics Data System (ADS)

    Mini, C.; Hogue, T. S.; Pincetl, S.

    2011-12-01

    water use patterns across the City. The performance of the linear regression model is being tested and compared with other algorithm-based simulations for improved modeling of urban water consumption in the region. Ultimately, projects results will contribute to the implementation of sustainable strategies targeted to specific urban areas for a growing population under uncertain climate variability.

  17. Use of neural network models to estimate early egg production in broiler breeder hens through dietary nutrient intake.

    PubMed

    Faridi, A; Golian, A

    2011-12-01

    In this study, neural network (NN) models were constructed to predict early egg production in broiler breeder hens. By breaking down the early egg production data collected from 98 breeder houses into weekly intervals, 5 NN-based models were developed for 25 to 29 wk of age. Starting with 98 data lines for each week, the NN models were trained by 69 data lines and the remainder (n = 29) were considered as the testing set. The variables of interest for developing the models were ME (kcal/bird per day) and CP, TSAA, Lys, Ca, and available P (g/bird per day). The constructed models were subjected to an optimization algorithm. Therefore, the optimal values for the input variables to maximize early egg production in broiler breeder hens were obtained. Based on the considered criteria to evaluate the goodness of fit, the efficiency of NN-based models to estimate early egg production was confirmed. The optimization results revealed that the breeder hens consuming 407, 457, 470, 486, and 487 kcal of ME/bird per day showed the highest egg production during 25, 26, 27, 28, and 29 wk of age, respectively. Moreover, optimal performance of hens required the intake (g/bird per day) of the following during 25, 26, 27, 28, and 29 wk of age, respectively: CP: 20.3, 22.6, 25, 25.8, and 26; TSAA: 0.88, 1.02, 1.06, 1.07, and 1.07; Lys: 0.98, 1.0, 1.2, 1.3, and 1.32; Ca: 4.5, 4.6, 5.3, 5.0, and 5.4; and available P: 0.48, 0.55, 0.6, 0.61, and 0.62. Although the results showed that the energy and other nutrient requirements of broiler breeder hens during early egg production do not change in parallel with age, it seems that the company recommendations underestimated the nutrient requirements of hens during these weeks.

  18. Modeling Oceanic Primary Production: Photoacclimation and Nutrient Effects on Light-saturated Photosynthesis

    NASA Technical Reports Server (NTRS)

    Behrenfeld, Michael J.; Maranon, Emilio; Siegel, David A.; Hooker, Stanford B.

    2000-01-01

    In this report, we describe a new model (the 'PhotoAcc' model) for estimating changes in the light-saturated rate of chlorophyll-normalized phytoplankton carbon fixation (Pbmax). The model is based on measurements conducted during the Atlantic Meridional Transect studies and the Bermuda Time Series program. The PhotoAcc model explained 64% to 82% of the observed variability in Pbmax for our data set, whereas none of the previously published Pbmax models described over the past 44 years explained any of the variance. The significance of this result is that a primary limiting factor for extracting ocean carbon fixation rates from satellite measurements of near surface chlorophyll has been errors in the estimate of Pbmax. Our new model should thus result in much improved calculations of oceanic photosynthesis and thus the role of the oceans in the global carbon cycle.

  19. The role of water nitrogen retention in integrated nutrient management: assessment in a large basin using different modelling approaches

    NASA Astrophysics Data System (ADS)

    Grizzetti, Bruna; Passy, Paul; Billen, Gilles; Bouraoui, Fayçal; Garnier, Josette; Lassaletta, Luis

    2015-06-01

    Assessing the removal of nitrogen (temporary and permanent) in large river basins is complex due to the dependency on climate, hydrological and physical characteristics, and ecosystems functioning. Measurements are generally limited in number and do not account for the full integration of all processes contributing to nitrogen retention in the river basin. However, the estimation of nitrogen retention by the ecosystems is crucial to understanding the nitrate water pollution and the N2O emissions to the atmosphere, as well as the lag time between the implementation of agri-environmental measures to reduce nitrogen pollution and the improvement of water quality. Models have often been used to understand the dynamics of the river basin system. The objective of this study was to assess nitrogen retention in a large river basin, the Seine basin (∼65 000 km2, in France), through the application of three models with different levels of complexity developed for different specific purposes: the GREEN, SWAT and RiverStrahler models. The study analyses the different modelling approaches and compares their estimates of water nitrogen retention over an 11-year period. Then reflexions on the role played by nitrogen retention by aquatic ecosystems in integrated nutrient management are presented. The results of this study are relevant for the understanding of nitrogen retention processes at the large river basin scale and for the analysis of mitigation measure scenarios designed to reduce nitrogen impacts on aquatic ecosystems and climate.

  20. A stochastic method to characterize model uncertainty for a Nutrient TMDL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The U.S. EPA’s Total Maximum Daily Load (TMDL) program has encountered resistances in its implementation partly because of its strong dependence on mathematical models to set limitations on the release of impairing substances. The uncertainty associated with predictions of such models is often not s...

  1. Quantifying consumption rates of dissolved oxygen along bed forms

    NASA Astrophysics Data System (ADS)

    Boano, Fulvio; De Falco, Natalie; Arnon, Shai

    2016-04-01

    Streambed interfaces represent hotspots for nutrient transformations because they host different microbial species, and the evaluation of these reaction rates is important to assess the fate of nutrients in riverine environments. In this work we analyze a series of flume experiments on oxygen demand in dune-shaped hyporheic sediments under losing and gaining flow conditions. We employ a new modeling code to quantify oxygen consumption rates from observed vertical profiles of oxygen concentration. The code accounts for transport by molecular diffusion and water advection, and automatically determines the reaction rates that provide the best fit between observed and modeled concentration values. The results show that reaction rates are not uniformly distributed across the streambed, in agreement with the expected behavior predicted by hyporheic exchange theory. Oxygen consumption was found to be highly influenced by the presence of gaining or losing flow conditions, which controlled the delivery of labile DOC to streambed microorganisms.

  2. Seasonal nutrient and plankton dynamics in a physical-biological model of Crater Lake

    USGS Publications Warehouse

    Fennel, K.; Collier, R.; Larson, G.; Crawford, G.; Boss, E.

    2007-01-01

    A coupled 1D physical-biological model of Crater Lake is presented. The model simulates the seasonal evolution of two functional phytoplankton groups, total chlorophyll, and zooplankton in good quantitative agreement with observations from a 10-year monitoring study. During the stratified period in summer and early fall the model displays a marked vertical structure: the phytoplankton biomass of the functional group 1, which represents diatoms and dinoflagellates, has its highest concentration in the upper 40 m; the phytoplankton biomass of group 2, which represents chlorophyta, chrysophyta, cryptomonads and cyanobacteria, has its highest concentrations between 50 and 80 m, and phytoplankton chlorophyll has its maximum at 120 m depth. A similar vertical structure is a reoccurring feature in the available data. In the model the key process allowing a vertical separation between biomass and chlorophyll is photoacclimation. Vertical light attenuation (i.e., water clarity) and the physiological ability of phytoplankton to increase their cellular chlorophyll-to-biomass ratio are ultimately determining the location of the chlorophyll maximum. The location of the particle maxima on the other hand is determined by the balance between growth and losses and occurs where growth and losses equal. The vertical particle flux simulated by our model agrees well with flux measurements from a sediment trap. This motivated us to revisit a previously published study by Dymond et al. (1996). Dymond et al. used a box model to estimate the vertical particle flux and found a discrepancy by a factor 2.5-10 between their model-derived flux and measured fluxes from a sediment trap. Their box model neglected the exchange flux of dissolved and suspended organic matter, which, as our model and available data suggests is significant for the vertical exchange of nitrogen. Adjustment of Dymond et al.'s assumptions to account for dissolved and suspended nitrogen yields a flux estimate that is

  3. Modeling energy consumption of residential furnaces and boilers in U.S. homes

    SciTech Connect

    Lutz, James; Dunham-Whitehead, Camilla; Lekov, Alex; McMahon, James

    2004-02-01

    In 2001, DOE initiated a rulemaking process to consider whether to amend the existing energy efficiency standards for furnaces and boilers. A key factor in DOE's consideration of new standards is their cost-effectiveness to consumers. Determining cost-effectiveness requires an appropriate comparison of the additional first cost of energy efficiency design options with the savings in operating costs. This report describes calculation of equipment energy consumption (fuel and electricity) based on estimated conditions in a sample of homes that are representative of expected furnace and boiler installations. To represent actual houses with furnaces and boilers in the United States, we used a set of houses from the Residential Energy Consumption Survey of 1997 conducted by the Energy Information Administration. Our calculation methodology estimates the energy consumption of alternative (more-efficient) furnaces, if they were to be used in each house in place of the existing equipment. We developed the method of calculation described in this report for non-weatherized gas furnaces. We generalized the energy consumption calculation for this product class to the other furnace product classes. Fuel consumption calculations for boilers are similar to those for the other furnace product classes. The electricity calculations for boilers are simpler than for furnaces, because boilers do not provide thermal distribution for space cooling as furnaces often do.

  4. Bidirectional enantioselective effects of the GABAB receptor agonist baclofen in two mouse models of excessive ethanol consumption.

    PubMed

    Kasten, Chelsea R; Blasingame, Shelby N; Boehm, Stephen L

    2015-02-01

    The GABAB receptor agonist baclofen has been studied extensively in preclinical models of alcohol-use disorders, yet results on its efficacy have been uncertain. Racemic baclofen, which is used clinically, can be broken down into separate enantiomers of the drug. Baclofen has been shown to produce enantioselective effects in behavioral assays, including those modeling reflexive and sexual behavior. The current studies sought to characterize the enantioselective effects of baclofen in two separate models of ethanol consumption. The first was a Drinking-in-the-Dark procedure that provides "binge-like" ethanol access to mice by restricting access to a 2-h period, 3 h into the dark cycle. The second was a two-bottle choice procedure that utilized selectively bred High Alcohol Preferring 1 (HAP1) mice to model chronic ethanol access. HAP1 mice are selectively bred to consume pharmacologically relevant amounts of ethanol in a 24-h two-bottle choice paradigm. The results showed that baclofen yields enantioselective effects on ethanol intake in both models, and that these effects are bidirectional. Total ethanol intake was decreased by R(+)-baclofen, while total intake was increased by S(-)-baclofen in the binge-like and chronic drinking models. Whereas overall binge-like saccharin intake was significantly reduced by R(+)-baclofen, chronic intake was not significantly altered. S(-)-baclofen did not significantly alter saccharin intake. Neither enantiomer significantly affected locomotion during binge-like reinforcer consumption. Collectively, these results demonstrate that baclofen produces enantioselective effects on ethanol consumption. More importantly, the modulation of consumption is bidirectional. The opposing enantioselective effects may explain some of the variance seen in published baclofen literature.

  5. Prawn Shell Chitosan Has Anti-Obesogenic Properties, Influencing Both Nutrient Digestibility and Microbial Populations in a Pig Model.

    PubMed

    Egan, Áine M; Sweeney, Torres; Hayes, Maria; O'Doherty, John V

    2015-01-01

    The potential of natural products to prevent obesity have been investigated, with evidence to suggest that chitosan has anti-obesity effects. The current experiment investigated the anti-obesity potential of prawn shell derived chitosan on a range of variables relevant to obesity in a pig model. The two dietary treatment groups included in this 63 day study were: T1) basal diet and T2) basal diet plus 1000 ppm chitosan (n = 20 gilts per group (70 ± 0.90 kg). The parameter categories which were assessed included: performance, nutrient digestibility, serum leptin concentrations, nutrient transporter and digestive enzyme gene expression and gut microbial populations. Pigs offered chitosan had reduced feed intake and final body weight (P< 0.001), lower ileal digestibility of dry matter (DM), gross energy (GE) (P< 0.05) and reduced coefficient of apparent total tract digestibility (CATTD) of gross energy and nitrogen (P<0.05) when compared to the basal group. Fatty acid binding protein 2 (FABP2) gene expression was down-regulated in pigs offered chitosan (P = 0.05) relative to the basal diet. Serum leptin concentrations increased (P< 0.05) in animals offered the chitosan diet compared to pigs offered the basal diet. Fatness traits, back-fat depth (mm), fat content (kg), were significantly reduced while lean meat (%) was increased (P<0.05) in chitosan supplemented pigs. Pigs offered chitosan had decreased numbers of Firmicutes in the colon (P <0.05), and Lactobacillus spp. in both the caecum (P <0.05) and colon (P <0.001). Bifidobacteria populations were increased in the caecum of animals offered the chitosan diet (P <0.05). In conclusion, these findings suggest that prawn shell chitosan has potent anti-obesity/body weight control effects which are mediated through multiple biological systems in vivo.

  6. Prawn Shell Chitosan Has Anti-Obesogenic Properties, Influencing Both Nutrient Digestibility and Microbial Populations in a Pig Model

    PubMed Central

    Egan, Áine M.; Sweeney, Torres; Hayes, Maria; O’Doherty, John V.

    2015-01-01

    The potential of natural products to prevent obesity have been investigated, with evidence to suggest that chitosan has anti-obesity effects. The current experiment investigated the anti-obesity potential of prawn shell derived chitosan on a range of variables relevant to obesity in a pig model. The two dietary treatment groups included in this 63 day study were: T1) basal diet and T2) basal diet plus 1000 ppm chitosan (n = 20 gilts per group (70 ± 0.90 kg). The parameter categories which were assessed included: performance, nutrient digestibility, serum leptin concentrations, nutrient transporter and digestive enzyme gene expression and gut microbial populations. Pigs offered chitosan had reduced feed intake and final body weight (P< 0.001), lower ileal digestibility of dry matter (DM), gross energy (GE) (P< 0.05) and reduced coefficient of apparent total tract digestibility (CATTD) of gross energy and nitrogen (P<0.05) when compared to the basal group. Fatty acid binding protein 2 (FABP2) gene expression was down-regulated in pigs offered chitosan (P = 0.05) relative to the basal diet. Serum leptin concentrations increased (P< 0.05) in animals offered the chitosan diet compared to pigs offered the basal diet. Fatness traits, back-fat depth (mm), fat content (kg), were significantly reduced while lean meat (%) was increased (P<0.05) in chitosan supplemented pigs. Pigs offered chitosan had decreased numbers of Firmicutes in the colon (P <0.05), and Lactobacillus spp. in both the caecum (P <0.05) and colon (P <0.001). Bifidobacteria populations were increased in the caecum of animals offered the chitosan diet (P <0.05). In conclusion, these findings suggest that prawn shell chitosan has potent anti-obesity/body weight control effects which are mediated through multiple biological systems in vivo. PMID:26636332

  7. Prawn Shell Chitosan Has Anti-Obesogenic Properties, Influencing Both Nutrient Digestibility and Microbial Populations in a Pig Model.

    PubMed

    Egan, Áine M; Sweeney, Torres; Hayes, Maria; O'Doherty, John V

    2015-01-01

    The potential of natural products to prevent obesity have been investigated, with evidence to suggest that chitosan has anti-obesity effects. The current experiment investigated the anti-obesity potential of prawn shell derived chitosan on a range of variables relevant to obesity in a pig model. The two dietary treatment groups included in this 63 day study were: T1) basal diet and T2) basal diet plus 1000 ppm chitosan (n = 20 gilts per group (70 ± 0.90 kg). The parameter categories which were assessed included: performance, nutrient digestibility, serum leptin concentrations, nutrient transporter and digestive enzyme gene expression and gut microbial populations. Pigs offered chitosan had reduced feed intake and final body weight (P< 0.001), lower ileal digestibility of dry matter (DM), gross energy (GE) (P< 0.05) and reduced coefficient of apparent total tract digestibility (CATTD) of gross energy and nitrogen (P<0.05) when compared to the basal group. Fatty acid binding protein 2 (FABP2) gene expression was down-regulated in pigs offered chitosan (P = 0.05) relative to the basal diet. Serum leptin concentrations increased (P< 0.05) in animals offered the chitosan diet compared to pigs offered the basal diet. Fatness traits, back-fat depth (mm), fat content (kg), were significantly reduced while lean meat (%) was increased (P<0.05) in chitosan supplemented pigs. Pigs offered chitosan had decreased numbers of Firmicutes in the colon (P <0.05), and Lactobacillus spp. in both the caecum (P <0.05) and colon (P <0.001). Bifidobacteria populations were increased in the caecum of animals offered the chitosan diet (P <0.05). In conclusion, these findings suggest that prawn shell chitosan has potent anti-obesity/body weight control effects which are mediated through multiple biological systems in vivo. PMID:26636332

  8. How important is the choice of the nutrient profile model used to regulate broadcast advertising of foods to children? A comparison using a targeted data set

    PubMed Central

    Scarborough, P; Payne, C; Agu, C G; Kaur, A; Mizdrak, A; Rayner, M; Halford, J C G; Boyland, E

    2013-01-01

    Background/Objective: The World Health Assembly recommends that children's exposure to marketing of unhealthy foods should be reduced. Nutrient profile models have been developed that define ‘unhealthy' to support regulation of broadcast advertising of foods to children. The level of agreement between these models is not clear. The objective of this study was to measure the agreement between eight nutrient profile models that have been proposed for the regulation of marketing to children over (a) how many and (b) what kind of foods should be permitted to be advertised during television viewed by children. Subjects/Methods: A representative data set of commercials for foods broadcast during television viewed by children in the UK was collected in 2008. The data set consisted of 11 763 commercials for 336 different products or brands. This data set was supplemented with nutrition data from company web sites, food packaging and a food composition table, and the nutrient profile models were applied. Results: The percentage of commercials that would be permitted by the different nutrient profile models ranged from 2.1% (0.4%, 3.7%) to 47.4% (42.1%, 52.6%). Half of the pairwise comparisons between models yielded kappa statistics less than 0.2, indicating that there was little agreement between models. Conclusions: Policy makers considering the regulation of broadcast advertising to children should carefully consider the choice of nutrient profile model to support the regulation, as this choice will have considerable influence on the outcome of the regulation. PMID:23801095

  9. Modeling the Effect of External Carbon Source Addition under Different Electron Acceptor Conditions in Biological Nutrient Removal Activated Sludge Systems.

    PubMed

    Hu, Xiang; Wisniewski, Kamil; Czerwionka, Krzysztof; Zhou, Qi; Xie, Li; Makinia, Jacek

    2016-02-16

    The aim of this study was to expand the International Water Association Activated Sludge Model No. 2d (ASM2d) to predict the aerobic/anoxic behavior of polyphosphate accumulating organisms (PAOs) and "ordinary" heterotrophs in the presence of different external carbon sources and electron acceptors. The following new aspects were considered: (1) a new type of the readily biodegradable substrate, not available for the anaerobic activity of PAOs, (2) nitrite as an electron acceptor, and (3) acclimation of "ordinary" heterotrophs to the new external substrate via enzyme synthesis. The expanded model incorporated 30 new or modified process rate equations. The model was evaluated against data from several, especially designed laboratory experiments which focused on the combined effects of different types of external carbon sources (acetate, ethanol and fusel oil) and electron acceptors (dissolved oxygen, nitrate and nitrite) on the behavior of PAOs and "ordinary" heterotrophs. With the proposed expansions, it was possible to improve some deficiencies of the ASM2d in predicting the behavior of biological nutrient removal (BNR) systems with the addition of external carbon sources, including the effect of acclimation to the new carbon source. PMID:26783836

  10. Modeling the Effect of External Carbon Source Addition under Different Electron Acceptor Conditions in Biological Nutrient Removal Activated Sludge Systems.

    PubMed

    Hu, Xiang; Wisniewski, Kamil; Czerwionka, Krzysztof; Zhou, Qi; Xie, Li; Makinia, Jacek

    2016-02-16

    The aim of this study was to expand the International Water Association Activated Sludge Model No. 2d (ASM2d) to predict the aerobic/anoxic behavior of polyphosphate accumulating organisms (PAOs) and "ordinary" heterotrophs in the presence of different external carbon sources and electron acceptors. The following new aspects were considered: (1) a new type of the readily biodegradable substrate, not available for the anaerobic activity of PAOs, (2) nitrite as an electron acceptor, and (3) acclimation of "ordinary" heterotrophs to the new external substrate via enzyme synthesis. The expanded model incorporated 30 new or modified process rate equations. The model was evaluated against data from several, especially designed laboratory experiments which focused on the combined effects of different types of external carbon sources (acetate, ethanol and fusel oil) and electron acceptors (dissolved oxygen, nitrate and nitrite) on the behavior of PAOs and "ordinary" heterotrophs. With the proposed expansions, it was possible to improve some deficiencies of the ASM2d in predicting the behavior of biological nutrient removal (BNR) systems with the addition of external carbon sources, including the effect of acclimation to the new carbon source.

  11. Steady-state and transient modeling of tracer and nutrient distributions in the global ocean

    SciTech Connect

    Stocker, T.F.; Broecker, W.S.

    1993-03-08

    The balance of stable and decaying tracers was incorporated into a latitude-depth ocean circulation model which resolves the major ocean basin and is coupled to an atmospheric energy balance model. The modern distribution of radiocarbon and the analysis of artificial color tracers enabled the census of the deep water masses. We show that good agreement with the observation can be achieved if the surface forcing is modified. The same process could also account for long-term, large-scale changes of the global thermohaline circulation. Uptake rates of carbon are investigated using an inorganic carbon cycle model and performing 2 [times] CO[sub 2]-experiments. We prescribe the industrial evolution of pCO[sub 2] in the atmosphere from 1792 to 1988 and calculate the total flux of carbon into the world ocean. Results are in good agreement with two recent 3-dimensional model simulation. First results using an organic carbon cycle in this model are presented. Changes in the hydrological cycle can stabilize the thermohaline circulation in the Atlantic and enable simulation of climate events resembling the Younger Dryas. By adding the balance of radiocarbon the evolution of its atmospheric concentration is studied during rapid changes of deep ocean ventilation. A resumption of ventilation creates a rapid decrease of atmospheric radiocarbon which is able to mask the natural decay.

  12. Contrasting response to nutrient manipulation in Arctic mesocosms are reproduced by a minimum microbial food web model

    PubMed Central

    Larsen, Aud; Egge, Jorun K; Nejstgaard, Jens C; Di Capua, Iole; Thyrhaug, Runar; Bratbak, Gunnar; Thingstad, T Frede

    2015-01-01

    A minimum mathematical model of the marine pelagic microbial food web has previously shown to be able to reproduce central aspects of observed system response to different bottom-up manipulations in a mesocosm experiment Microbial Ecosystem Dynamics (MEDEA) in Danish waters. In this study, we apply this model to two mesocosm experiments (Polar Aquatic Microbial Ecology (PAME)-I and PAME-II) conducted at the Arctic location Kongsfjorden, Svalbard. The different responses of the microbial community to similar nutrient manipulation in the three mesocosm experiments may be described as diatom-dominated (MEDEA), bacteria-dominated (PAME-I), and flagellated-dominated (PAME-II). When allowing ciliates to be able to feed on small diatoms, the model describing the diatom-dominated MEDEA experiment give a bacteria-dominated response as observed in PAME I in which the diatom community comprised almost exclusively small-sized cells. Introducing a high initial mesozooplankton stock as observed in PAME-II, the model gives a flagellate-dominated response in accordance with the observed response also of this experiment. The ability of the model originally developed for temperate waters to reproduce population dynamics in a 10°C colder Arctic fjord, does not support the existence of important shifts in population balances over this temperature range. Rather, it suggests a quite resilient microbial food web when adapted to in situ temperature. The sensitivity of the model response to its mesozooplankton component suggests, however, that the seasonal vertical migration of Arctic copepods may be a strong forcing factor on Arctic microbial food webs. PMID:26074626

  13. Modeling Stochastic Energy and Water Consumption to Manage Residential Water Uses

    NASA Astrophysics Data System (ADS)

    Abdallah, A. M.; Rosenberg, D. E.; Water; Energy Conservation

    2011-12-01

    Water energy linkages have received growing attention from the water and energy utilities as utilities recognize that collaborative efforts can implement more effective conservation and efficiency improvement programs at lower cost with less effort. To date, limited energy-water household data has allowed only deterministic analysis for average, representative households and required coarse assumptions - like the water heater (the primary energy use in a home apart from heating and cooling) be a single end use. Here, we use recent available disaggregated hot and cold water household end-use data to estimate water and energy consumption for toilet, shower, faucet, dishwasher, laundry machine, leaks, and other household uses and savings from appliance retrofits. The disaggregated hot water and bulk water end-use data was previously collected by the USEPA for 96 single family households in Seattle WA and Oakland CA, and Tampa FL between the period from 2000 and 2003 for two weeks before and four weeks after each household was retrofitted with water efficient appliances. Using the disaggregated data, we developed a stochastic model that represents factors that influence water use for each appliance: behavioral (use frequency and duration), demographical (household size), and technological (use volume or flowrate). We also include stochastic factors that govern energy to heat hot water: hot water fraction (percentage of hot water volume to total water volume used in a certain end-use event), heater water intake and dispense temperatures, and energy source for the heater (gas, electric, etc). From the empirical household end-use data, we derive stochastic probability distributions for each water and energy factor where each distribution represents the range and likelihood of values that the factor may take. The uncertainty of the stochastic water and energy factors is propagated using Monte Carlo simulations to calculate the composite probability distribution for water

  14. Modeling transport of nutrients & sediment loads into Lake Tahoe under climate change

    USGS Publications Warehouse

    Riverson, John; Coats, Robert; Costa-Cabral, Mariza; Dettinger, Mike; Reuter, John; Sahoo, Goloka; Schladow, Geoffrey

    2013-01-01

    The outputs from two General Circulation Models (GCMs) with two emissions scenarios were downscaled and bias-corrected to develop regional climate change projections for the Tahoe Basin. For one model—the Geophysical Fluid Dynamics Laboratory or GFDL model—the daily model results were used to drive a distributed hydrologic model. The watershed model used an energy balance approach for computing evapotranspiration and snowpack dynamics so that the processes remain a function of the climate change projections. For this study, all other aspects of the model (i.e. land use distribution, routing configuration, and parameterization) were held constant to isolate impacts of climate change projections. The results indicate that (1) precipitation falling as rain rather than snow will increase, starting at the current mean snowline, and moving towards higher elevations over time; (2) annual accumulated snowpack will be reduced; (3) snowpack accumulation will start later; and (4) snowmelt will start earlier in the year. Certain changes were masked (or counter-balanced) when summarized as basin-wide averages; however, spatial evaluation added notable resolution. While rainfall runoff increased at higher elevations, a drop in total precipitation volume decreased runoff and fine sediment load from the lower elevation meadow areas and also decreased baseflow and nitrogen loads basin-wide. This finding also highlights the important role that the meadow areas could play as high-flow buffers under climatic change. Because the watershed model accounts for elevation change and variable meteorological patterns, it provided a robust platform for evaluating the impacts of projected climate change on hydrology and water quality.

  15. Steady-state and transient modeling of tracer and nutrient distributions in the global ocean

    SciTech Connect

    Stocker, T.F.; Broecker, W.S.

    1992-03-26

    The deep circulation model developed by Wright and Stocker has been used to represent the latitude-depth distributions of temperature, salinity, radiocarbon and color'' tracers in the Pacific, Atlantic and Indian Oceans. Restoring temperature and salinity to observed surface data the model shows a global thermohaline circulation where deep water is formed in the North Atlantic and in the Southern Ocean. A parameter study reveals that the high-latitude surface salinity determines the composition of deep water and its flow in the global ocean. Increasing Southern Ocean surface salinity by 0.4 ppt the circulation changes from a present-day mode where North Atlantic Deep Water is one where Antarctic Bottom Water is dominant. An inorganic carbon cycle with surface carbonate chemistry is included, and gas exchange is parameterized in terms of pCO{sub 2} differences. Pre- industrial conditions are achieved by adjusting the basin-mean alkalinity. A classical 2{times}CO{sub 2} experiment yields the intrinsic time scales for carbon uptake of the ocean; they agree with those obtained from simple box models or 3-dimensional ocean general circulation models. Using the estimated industrial anthropogenic input of CO{sub 2} into the atmosphere the model requires, consistent with other model studies, an additional carbon flux to match the observed increase of atmospheric pCO{sub 2}. We use more realistic surface boundary conditions which reduce sensitivity to freshwater discharges into the ocean. In a glacial-to-interglacial experiment rapid transitions of the deep circulation between two different states occur in conjunction with a severe reduction of the meridional heat flux and sea surface temperature during peak melting. After the melting the conveyor belt circulation restarts.

  16. Simulation of annual biogeochemical cycles of nutrient balance, phytoplankton bloom(s), and DO in Puget Sound using an unstructured grid model

    NASA Astrophysics Data System (ADS)

    Khangaonkar, Tarang; Sackmann, Brandon; Long, Wen; Mohamedali, Teizeen; Roberts, Mindy

    2012-09-01

    Nutrient pollution from rivers, nonpoint source runoff, and nearly 100 wastewater discharges is a potential threat to the ecological health of Puget Sound with evidence of hypoxia in some basins. However, the relative contributions of loads entering Puget Sound from natural and anthropogenic sources, and the effects of exchange flow from the Pacific Ocean are not well understood. Development of a quantitative model of Puget Sound is thus presented to help improve our understanding of the annual biogeochemical cycles in this system using the unstructured grid Finite-Volume Coastal Ocean Model framework and the Integrated Compartment Model (CE-QUAL-ICM) water quality kinetics. Results based on 2006 data show that phytoplankton growth and die-off, succession between two species of algae, nutrient dynamics, and dissolved oxygen in Puget Sound are strongly tied to seasonal variation of temperature, solar radiation, and the annual exchange and flushing induced by upwelled Pacific Ocean waters. Concentrations in the mixed outflow surface layer occupying approximately 5-20 m of the upper water column show strong effects of eutrophication from natural and anthropogenic sources, spring and summer algae blooms, accompanied by depleted nutrients but high dissolved oxygen levels. The bottom layer reflects dissolved oxygen and nutrient concentrations of upwelled Pacific Ocean water modulated by mixing with biologically active surface outflow in the Strait of Juan de Fuca prior to entering Puget Sound over the Admiralty Inlet. The effect of reflux mixing at the Admiralty Inlet sill resulting in lower nutrient and higher dissolved oxygen levels in bottom waters of Puget Sound than the incoming upwelled Pacific Ocean water is reproduced. By late winter, with the reduction in algal activity, water column constituents of interest, were renewed and the system appeared to reset with cooler temperature, higher nutrient, and higher dissolved oxygen waters from the Pacific Ocean.

  17. Simulation of annual biogeochemical cycles of nutrient balance, phytoplankton bloom(s), and DO in Puget Sound using an unstructured grid model

    SciTech Connect

    Khangaonkar, Tarang; Sackmann, Brandon; Long, Wen; Mohamedali, Teizeen; Roberts, Mindy

    2012-08-14

    Nutrient pollution from rivers, nonpoint source runoff, and nearly 100 wastewater discharges is a potential threat to the ecological health of Puget Sound with evidence of hypoxia in some basins. However, the relative contributions of loads entering Puget Sound from natural and anthropogenic sources, and the effects of exchange flow from the Pacific Ocean are not well understood. Development of a quantitative model of Puget Sound is thus presented to help improve our understanding of the annual biogeochemical cycles in this system using the unstructured grid Finite-Volume Coastal Ocean Model framework and the Integrated Compartment Model (CE-QUAL-ICM) water quality kinetics. Results based on 2006 data show that phytoplankton growth and die-off, succession between two species of algae, nutrient dynamics, and dissolved oxygen in Puget Sound are strongly tied to seasonal variation of temperature, solar radiation, and the annual exchange and flushing induced by upwelled Pacific Ocean waters. Concentrations in the mixed outflow surface layer occupying approximately 5–20 m of the upper water column show strong effects of eutrophication from natural and anthropogenic sources, spring and summer algae blooms, accompanied by depleted nutrients but high dissolved oxygen levels. The bottom layer reflects dissolved oxygen and nutrient concentrations of upwelled Pacific Ocean water modulated by mixing with biologically active surface outflow in the Strait of Juan de Fuca prior to entering Puget Sound over the Admiralty Inlet. The effect of reflux mixing at the Admiralty Inlet sill resulting in lower nutrient and higher dissolved oxygen levels in bottom waters of Puget Sound than the incoming upwelled Pacific Ocean water is reproduced. Finally, by late winter, with the reduction in algal activity, water column constituents of interest, were renewed and the system appeared to reset with cooler temperature, higher nutrient, and higher dissolved oxygen waters from the Pacific

  18. Experimental Models of Foamy Macrophages and Approaches for Dissecting the Mechanisms of Lipid Accumulation and Consumption during Dormancy and Reactivation of Tuberculosis

    PubMed Central

    Santucci, Pierre; Bouzid, Feriel; Smichi, Nabil; Poncin, Isabelle; Kremer, Laurent; De Chastellier, Chantal; Drancourt, Michel; Canaan, Stéphane

    2016-01-01

    Despite a slight decline since 2014, tuberculosis (TB) remains the major deadly infectious disease worldwide with about 1.5 million deaths each year and with about one-third of the population being latently infected with Mycobacterium tuberculosis, the etiologic agent of TB. During primo-infection, the recruitment of immune cells leads to the formation of highly organized granulomas. Among the different cells, one outstanding subpopulation is the foamy macrophage (FM), characterized by the abundance of triacylglycerol-rich lipid bodies (LB). M. tuberculosis can reside in FM, where it acquires, from host LB, the neutral lipids which are subsequently processed and stored by the bacilli in the form of intracytosolic lipid inclusions (ILI). Although host LB can be viewed as a reservoir of nutrients for the pathogen during latency, the molecular mechanisms whereby intraphagosomal mycobacteria interact with LB and assimilate the LB-derived lipids are only beginning to be understood. Past studies have emphasized that these physiological processes are critical to the M. tuberculosis infectious-life cycle, for propagation of the infection, establishment of the dormancy state and reactivation of the disease. In recent years, several animal and cellular models have been developed with the aim of dissecting these complex processes and of determining the nature and contribution of their key players. Herein, we review some of the in vitro and in vivo models which allowed to gain significant insight into lipid accumulation and consumption in M. tuberculosis, two important events that are directly linked to pathogenicity, granuloma formation/maintenance and survival of the tubercle bacillus under non-replicative conditions. We also discuss the advantages and limitations of each model, hoping that this will serve as a guide for future investigations dedicated to persistence and innovative therapeutic approaches against TB. PMID:27774438

  19. Effect of the tobacco price support program on cigarette consumption in the United States: an updated model.

    PubMed Central

    Zhang, P; Husten, C; Giovino, G

    2000-01-01

    OBJECTIVES: This study evaluated the direct effect of the tobacco price support program on domestic cigarette consumption. METHODS: We developed an economic model of demand and supply of US tobacco to estimate how much the price support program increases the price of tobacco. We calculated the resultant increase in cigarette prices from the change in the tobacco price and the quantity of domestic tobacco contained in US cigarettes. We then assessed the reduction in cigarette consumption attributable to the price support program by applying the estimated increase in the cigarette price to assumed price elasticities of demand for cigarettes. RESULTS: We estimated that the tobacco price support program increased the price of tobacco leaf by $0.36 per pound. This higher tobacco price translates to a $0.01 increase in the price of a pack of cigarettes and an estimated 0.21% reduction in cigarette consumption. CONCLUSION: Because the tobacco price support program increases the price of cigarettes minimally, its potential health benefit is likely to be small. The adverse political effect of the tobacco program might substantially outweigh the potential direct benefit of the program on cigarette consumption. PMID:10800423

  20. Diffusion and Monod kinetics model to determine in vivo human corneal oxygen-consumption rate during soft contact lens wear

    PubMed Central

    Del Castillo, Luis F.; da Silva, Ana R. Ferreira; Hernández, Saul I.; Aguilella, M.; Andrio, Andreu; Mollá, Sergio; Compañ, Vicente

    2014-01-01

    Purpose We present an analysis of the corneal oxygen consumption Qc from non-linear models, using data of oxygen partial pressure or tension (pO2) obtained from in vivo estimation previously reported by other authors.1 Methods Assuming that the cornea is a single homogeneous layer, the oxygen permeability through the cornea will be the same regardless of the type of lens that is available on it. The obtention of the real value of the maximum oxygen consumption rate Qc,max is very important because this parameter is directly related with the gradient pressure profile into the cornea and moreover, the real corneal oxygen consumption is influenced by both anterior and posterior oxygen fluxes. Results Our calculations give different values for the maximum oxygen consumption rate Qc,max, when different oxygen pressure values (high and low pO2) are considered at the interface cornea-tears film. Conclusion Present results are relevant for the calculation on the partial pressure of oxygen, available at different depths into the corneal tissue behind contact lenses of different oxygen transmissibility. PMID:25649636

  1. What are the unique attributes of potassium that challenge existing nutrient uptake models?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil potassium (K) availability and acquisition by plant root systems are controlled by complex, interacting processes that make it difficult to assess their individual impacts on crop growth. Mechanistic, mathematical models provide an important tool to enhance understanding of these processes, and...

  2. Response of a One-Biosphere Nutrient Modeling System to Regional Land Use and Management Change

    EPA Science Inventory

    A multi-media system of nitrogen and co-pollutant models describing critical physical and chemical processes that cascade synergistically and competitively through the environment, the economy and society has been developed at the USEPA Office of Research and Development (see fig...

  3. Modeled summer background concentration nutrients and suspended sediment in the mid-continent (USA) great rivers

    EPA Science Inventory

    We used regression models to predict background concentration of four water quality indictors: total nitrogen (N), total phosphorus (P), chloride, and total suspended solids (TSS), in the mid-continent (USA) great rivers, the Upper Mississippi, the Lower Missouri, and the Ohio. F...

  4. Development and deployment of a water-crop-nutrient simulation model embedded in a web application

    NASA Astrophysics Data System (ADS)

    Langella, Giuliano; Basile, Angelo; Coppola, Antonio; Manna, Piero; Orefice, Nadia; Terribile, Fabio

    2016-04-01

    It is long time by now that scientific research on environmental and agricultural issues spent large effort in the development and application of models for prediction and simulation in spatial and temporal domains. This is fulfilled by studying and observing natural processes (e.g. rainfall, water and chemicals transport in soils, crop growth) whose spatiotemporal behavior can be reproduced for instance to predict irrigation and fertilizer requirements and yield quantities/qualities. In this work a mechanistic model to simulate water flow and solute transport in the soil-plant-atmosphere continuum is presented. This desktop computer program was written according to the specific requirement of developing web applications. The model is capable to solve the following issues all together: (a) water balance and (b) solute transport; (c) crop modelling; (d) GIS-interoperability; (e) embedability in web-based geospatial Decision Support Systems (DSS); (f) adaptability at different scales of application; and (g) ease of code modification. We maintained the desktop characteristic in order to further develop (e.g. integrate novel features) and run the key program modules for testing and validation purporses, but we also developed a middleware component to allow the model run the simulations directly over the web, without software to be installed. The GIS capabilities allows the web application to make simulations in a user-defined region of interest (delimited over a geographical map) without the need to specify the proper combination of model parameters. It is possible since the geospatial database collects information on pedology, climate, crop parameters and soil hydraulic characteristics. Pedological attributes include the spatial distribution of key soil data such as soil profile horizons and texture. Further, hydrological parameters are selected according to the knowledge about the spatial distribution of soils. The availability and definition in the geospatial domain

  5. Watershed Modeling to Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to Potential Climate Change and Urban Development in 20 U.S. Watersheds (Final Report)

    EPA Science Inventory

    Watershed modeling was conducted in 20 large, U.S. watersheds to assess the sensitivity of streamflow, nutrient (nitrogen and phosphorus), and sediment loading to a range of plausible mid-21st Century climate change and urban development scenarios in different regions of the nati...

  6. Watershed Modeling to Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to Potential Climate Change and Urban Development in 20 U.S. Watersheds (External Review Draft)

    EPA Science Inventory

    EPA has released for independent external peer review and public comment a draft report titled, Watershed Modeling to Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to Potential Climate Change and Urban Development in 20 U.S. Watersheds. This is a draft...

  7. Consumption of lycopene inhibits the growth and progression of colon cancer in a mouse xenograft model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previous study indicated that lycopene could significantly inhibit the proliferation of human colon cancer cells in vitro. However, the in vivo anticancer effects of lycopene against colon cancer have not been demonstrated yet. Therefore, this study investigated whether consumption of lycopene cou...

  8. Modelling potential ß-carotene intake and cyanide exposure from consumption of biofortified cassava

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Vitamin A (VA) deficiency causes disability and mortality. Cassava, a staple crop in Africa, can be crossbred to improve its pro-vitamin A (PVA) content and used as an alternative to capsule supplementation. However it contains cyanide and its continued consumption may lead to chronic...

  9. Modeling land-based nitrogen loads from groundwater-dominated agricultural watersheds to estuaries to inform nutrient reduction planning

    NASA Astrophysics Data System (ADS)

    Jiang, Yefang; Nishimura, Peter; van den Heuvel, Michael R.; MacQuarrie, Kerry T. B.; Crane, Cindy S.; Xing, Zisheng; Raymond, Bruce G.; Thompson, Barry L.

    2015-10-01

    Excessive nitrate loads from intensive potato production have been linked to the reoccurring anoxic events in many estuaries in Prince Edward Island (PEI), Canada. Community-led watershed-based nutrient reduction planning has been promoted as a strategy for water quality restoration and initial nitrate load criteria have been proposed for the impacted estuaries. An integrated modeling approach was developed to predict base flow nitrate loads to inform the planning activities in the groundwater-dominated agricultural watersheds. Nitrate load is calculated as base flow multiplied by the average of nitrate concentration at the receiving watershed outlet. The average of nitrate concentration is estimated as the integration of nitrate leaching concentration over the watershed area minus a nitrate loss coefficient that accounts for long-term nitrate storage in the aquifer and losses from the recharge to the discharge zones. Nitrate leaching concentrations from potato rotation systems were estimated with a LEACHN model and the land use areas were determined from satellite image data (2006-2009) using GIS. The simulated average nitrate concentrations are compared with the arithmetic average of nitrate concentration measurements in each of the 27 watersheds for model calibration and in 138 watersheds for model verifications during 2006-2009. Sensitivity of the model to the variations of land use mapping errors, nitrate leaching concentrations from key sources, and nitrate loss coefficient was tested. The calibration and verification statistics and sensitivity analysis show that the model can provide accurate nitrate concentration predictions for watersheds with drainage areas more than 5 km2 and nitrate concentration over 2 mg N L-1, while the model resolution for watersheds with drainage areas below 5 km2 and/or nitrate concentration below 2 mg N L-1 may not be sufficient for nitrate load management purposes. Comparisons of normalized daily stream discharges among the

  10. Oat consumption reduced intestinal fat deposition and improved health span in Caenorhabditis elegans model.

    PubMed

    Gao, Chenfei; Gao, Zhanguo; Greenway, Frank L; Burton, Jeffrey H; Johnson, William D; Keenan, Michael J; Enright, Frederick M; Martin, Roy J; Chu, YiFang; Zheng, Jolene

    2015-09-01

    In addition to their fermentable dietary fiber and the soluble β-glucan fiber, oats have unique avenanthramides that have anti-inflammatory and antioxidant properties that reduce coronary heart disease in human clinical trials. We hypothesized that oat consumption will increase insulin sensitivity, reduce body fat, and improve health span in Caenorhabditis elegans through a mechanism involving the daf-2 gene, which codes for the insulin/insulin-like growth factor-1-like receptor, and that hyperglycemia will attenuate these changes. Caenorhabditis elegans wild type (N2) and the null strains sir-2.1, daf-16, and daf-16/daf-2 were fed Escherichia coli (OP50) and oat flakes (0.5%, 1.0%, or 3%) with and without 2% glucose. Oat feeding decreased intestinal fat deposition in N2, daf-16, or daf-16/daf-2 strains (P < .05); and glucose did not affect intestinal fat deposition response. The N2, daf-16, or sir-2.1 mutant increased the pharyngeal pumping rate (P < .05), a surrogate marker of life span, following oat consumption. Oat consumption increased ckr-1, gcy-8, cpt-1, and cpt-2 mRNA expression in both the N2 and the sir-2.1 mutant, with significantly higher expression in sir-2.1 than in N2 (P < .01). Additional glucose further increased expression 1.5-fold of the 4 genes in N2 (P < .01), decreased the expression of all except cpt-1 in the daf-16 mutant, and reduced mRNA expression of the 4 genes in the daf-16/daf-2 mutant (P < .01). These data suggest that oat consumption reduced fat storage and increased ckr-1, gcy-8, cpt-1, or cpt-2 through the sir-2.1 genetic pathway. Oat consumption may be a beneficial dietary intervention for reducing fat accumulation, augmenting health span, and improving hyperglycemia-impaired lipid metabolism.

  11. Oat consumption reduced intestinal fat deposition and improved health span in Caenorhabditis elegans model.

    PubMed

    Gao, Chenfei; Gao, Zhanguo; Greenway, Frank L; Burton, Jeffrey H; Johnson, William D; Keenan, Michael J; Enright, Frederick M; Martin, Roy J; Chu, YiFang; Zheng, Jolene

    2015-09-01

    In addition to their fermentable dietary fiber and the soluble β-glucan fiber, oats have unique avenanthramides that have anti-inflammatory and antioxidant properties that reduce coronary heart disease in human clinical trials. We hypothesized that oat consumption will increase insulin sensitivity, reduce body fat, and improve health span in Caenorhabditis elegans through a mechanism involving the daf-2 gene, which codes for the insulin/insulin-like growth factor-1-like receptor, and that hyperglycemia will attenuate these changes. Caenorhabditis elegans wild type (N2) and the null strains sir-2.1, daf-16, and daf-16/daf-2 were fed Escherichia coli (OP50) and oat flakes (0.5%, 1.0%, or 3%) with and without 2% glucose. Oat feeding decreased intestinal fat deposition in N2, daf-16, or daf-16/daf-2 strains (P < .05); and glucose did not affect intestinal fat deposition response. The N2, daf-16, or sir-2.1 mutant increased the pharyngeal pumping rate (P < .05), a surrogate marker of life span, following oat consumption. Oat consumption increased ckr-1, gcy-8, cpt-1, and cpt-2 mRNA expression in both the N2 and the sir-2.1 mutant, with significantly higher expression in sir-2.1 than in N2 (P < .01). Additional glucose further increased expression 1.5-fold of the 4 genes in N2 (P < .01), decreased the expression of all except cpt-1 in the daf-16 mutant, and reduced mRNA expression of the 4 genes in the daf-16/daf-2 mutant (P < .01). These data suggest that oat consumption reduced fat storage and increased ckr-1, gcy-8, cpt-1, or cpt-2 through the sir-2.1 genetic pathway. Oat consumption may be a beneficial dietary intervention for reducing fat accumulation, augmenting health span, and improving hyperglycemia-impaired lipid metabolism. PMID:26253816

  12. Using models to guide field experiments: a priori predictions for the CO 2 response of a nutrien