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Sample records for experimental nutrient addition

  1. Experimental nutrient additions accelerate terrestrial carbon loss from stream ecosystems

    Science.gov (United States)

    Amy D. Rosemond; Jonathan P. Benstead; Phillip M. Bumpers; Vladislav Gulis; John S. Kominoski; David W.P. Manning; Keller Suberkropp; J. Bruce. Wallace

    2015-01-01

    Nutrient pollution of freshwater ecosystems results in predictable increases in carbon (C) sequestration by algae. Tests of nutrient enrichment on the fates of terrestrial organic C, which supports riverine food webs and is a source of CO2, are lacking. Using whole-stream nitrogen (N) and phosphorus (P) additions spanning the equivalent of 27 years, we found that...

  2. Freshwater ecology. Experimental nutrient additions accelerate terrestrial carbon loss from stream ecosystems.

    Science.gov (United States)

    Rosemond, Amy D; Benstead, Jonathan P; Bumpers, Phillip M; Gulis, Vladislav; Kominoski, John S; Manning, David W P; Suberkropp, Keller; Wallace, J Bruce

    2015-03-06

    Nutrient pollution of freshwater ecosystems results in predictable increases in carbon (C) sequestration by algae. Tests of nutrient enrichment on the fates of terrestrial organic C, which supports riverine food webs and is a source of CO2, are lacking. Using whole-stream nitrogen (N) and phosphorus (P) additions spanning the equivalent of 27 years, we found that average terrestrial organic C residence time was reduced by ~50% as compared to reference conditions as a result of nutrient pollution. Annual inputs of terrestrial organic C were rapidly depleted via release of detrital food webs from N and P co-limitation. This magnitude of terrestrial C loss can potentially exceed predicted algal C gains with nutrient enrichment across large parts of river networks, diminishing associated ecosystem services. Copyright © 2015, American Association for the Advancement of Science.

  3. Characterization of the Kootenai River Aquatic Macroinvertebrate Community before and after Experimental Nutrient Addition, 2003-2006. [Chapter 3

    Energy Technology Data Exchange (ETDEWEB)

    Holderman, Charlie [Kootenai Tribe of Idaho Bonners

    2009-02-19

    The Kootenai River ecosystem has experienced numerous ecological changes since the early 1900s. Some of the largest impacts to habitat, biological communities, and ecological function resulted from levee construction along the 120 km of river upstream from Kootenay Lake, completed by the 1950s, and the construction and operation of Libby Dam, completed in 1972 on the river near Libby Montana. Levee construction isolated tens of thousands of hectares of historic functioning floodplain habitat from the river channel, eliminating nutrient production and habitat diversity crucial to the functioning of a large river-floodplain ecosystem. Libby Dam continues to create large changes in the timing, duration, and magnitude of river flows, and greatly reduces sediment and nutrient transport to downstream river reaches. These changes have contributed to the ecological collapse of the post-development Kootenai River ecosystem and its native biological communities. In response to this artificial loss of nutrients, experimental nutrient addition was initiated in the Kootenay Lake's North Arm in 1992, the South Arm in 2004, and in the Kootenai River at the Idaho-Montana border during 2005. This report characterizes the macroinvertebrate community in the Kootenai River and its response to experimental nutrient addition during 2005 and 2006. This report also provides an initial evaluation of cascading trophic interactions in response to nutrient addition. Macroinvertebrates were sampled at 12 sites along a 325 km section of the Kootenai River, representing an upriver unimpounded reference reach, treatment and control canyon reach sites, and braided and meandering reach sites, all downstream from Libby Dam. Principle component analysis revealed that richness explained the greatest amount of variability in response to nutrient addition as did taxa from Acari, Coleoptera, Ephemeroptera, Plecoptera, and Trichoptera. Analysis of variance revealed that nutrient addition had a

  4. Effects of nutrient additions and macrophyte composition on invertebrate community assembly and diversity in experimental ponds.

    NARCIS (Netherlands)

    Declerck, S.A.J.; Bakker, E.S.; van Lith, B.; Kersbergen, A.P.; Van Donk, E.

    2011-01-01

    Macrophytes and nutrient loading are two factors that can strongly determine the diversity and composition of aquatic invertebrate communities. Both factors may also interact, because macrophyte species may be differentially affected by nutrients. Macrophyte community characteristics, such as

  5. Effects of flow events and nutrient addition on stream periphyton and macroinvertebrates: an experimental study using flumes

    Directory of Open Access Journals (Sweden)

    Bækkelie Knut Andreas E.

    2017-01-01

    Full Text Available We used flume experiments to study the effects of a temporary increase in stream flow on macroinvertebrates, leaf litter breakdown and soft-bodied benthic algae; both as a single stressor and eventually in combination with an increase in nutrient supply. In order to understand how well the flumes reflected the nearby stream ecosystem, we compared species composition of macroinvertebrates and benthic algae between the flumes and the nearby stream from which the flumes were supplied with water. As single stressors, nutrient addition and an increased flow velocity from 1.3 to 2.8 cm s−1 lead to an increase in the biomass of benthic algae, likely reflecting an improved transfer of nutrients into algal patches. However, the combined effect of flow and nutrient addition was smaller than the sum of both individual effects, likely because an increased biomass also was more susceptible to scouring. We found differences in macroinvertebrate and benthic algal taxon identity and abundance between stream and flumes. Since biodiversity is assumed to stabilize ecological functioning in response to disturbances and variation, we conclude that care should be taken in applying results from small scale experiments to stream ecosystems.

  6. Individual and population indicators of Zostera japonica respond quickly to experimental addition of sediment-nutrient and organic matter

    NARCIS (Netherlands)

    Han, Q.; Soissons, L.M.; Liu, D.; van Katwijk, M.; Bouma, T.J.

    2017-01-01

    Amanipulative field experimentwas designed to investigate the effects of sediment-nutrients and sediment-organicmatterson seagrasses, Zostera japonica, using individual and population indicators. The results showed thatseagrasses quickly responded to sediment-nutrient and organicmatter loading. That

  7. Interactive effects of nutrient additions and predation on infaunal communities

    Science.gov (United States)

    Posey, M.H.; Alphin, T.D.; Cahoon, L.; Lindquist, D.; Becker, M.E.

    1999-01-01

    Nutrient additions represent an important anthropogenic stress on coastal ecosystems. At moderate levels, increased nutrients may lead to increased primary production and, possibly, to increased biomass of consumers although complex trophic interactions may modify or mask these effects. We examined the influence of nutrient additions and interactive effects of trophic interactions (predation) on benthic infaunal composition and abundances through small-scale field experiments in 2 estuaries that differed in ambient nutrient conditions. A blocked experimental design was used that allowed an assessment of direct nutrient effects in the presence and absence of predation by epibenthic predators as well as an assessment of the independent effects of predation. Benthic microalgal production increased with experimental nutrient additions and was greater when infaunal abundances were lower, but there were no significant interactions between these factors. Increased abundances of one infaunal taxa, Laeonereis culveri, as well as the grazer feeding guild were observed with nutrient additions and a number of taxa exhibited higher abundances with predator exclusion. In contrast to results from freshwater systems there were no significant interactive effects between nutrient additions and predator exclusion as was predicted. The infaunal responses observed here emphasize the importance of both bottom-up (nutrient addition and primary producer driven) and top-down (predation) controls in structuring benthic communities. These processes may work at different spatial and temporal scales, and affect different taxa, making observation of potential interactive effects difficult.

  8. Tropical Andean Forests Are Highly Susceptible to Nutrient Inputs—Rapid Effects of Experimental N and P Addition to an Ecuadorian Montane Forest

    Science.gov (United States)

    Homeier, Jürgen; Hertel, Dietrich; Camenzind, Tessa; Cumbicus, Nixon L.; Maraun, Mark; Martinson, Guntars O.; Poma, L. Nohemy; Rillig, Matthias C.; Sandmann, Dorothee; Scheu, Stefan; Veldkamp, Edzo; Wilcke, Wolfgang; Wullaert, Hans; Leuschner, Christoph

    2012-01-01

    Tropical regions are facing increasing atmospheric inputs of nutrients, which will have unknown consequences for the structure and functioning of these systems. Here, we show that Neotropical montane rainforests respond rapidly to moderate additions of N (50 kg ha−1 yr−1) and P (10 kg ha−1 yr−1). Monitoring of nutrient fluxes demonstrated that the majority of added nutrients remained in the system, in either soil or vegetation. N and P additions led to not only an increase in foliar N and P concentrations, but also altered soil microbial biomass, standing fine root biomass, stem growth, and litterfall. The different effects suggest that trees are primarily limited by P, whereas some processes—notably aboveground productivity—are limited by both N and P. Highly variable and partly contrasting responses of different tree species suggest marked changes in species composition and diversity of these forests by nutrient inputs in the long term. The unexpectedly fast response of the ecosystem to moderate nutrient additions suggests high vulnerability of tropical montane forests to the expected increase in nutrient inputs. PMID:23071734

  9. Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics

    Science.gov (United States)

    Marcarelli, Amy M.; Baxter, Colden V.; Wipfli, Mark S.

    2014-01-01

    Mitigation activities designed to supplement nutrient and organic matter inputs to streams experiencing decline or loss of Pacific salmon typically presuppose that an important pathway by which salmon nutrients are moved to fish (anadromous and/or resident) is via nutrient incorporation by biofilms and subsequent bottom-up stimulation of biofilm production, which is nutrient-limited in many ecosystems where salmon returns have declined. Our objective was to quantify the magnitude of nutrient incorporation and biofilm dynamics that underpin this indirect pathway in response to experimental additions of salmon carcasses and pelletized fish meal (a.k.a., salmon carcass analogs) to 500-m reaches of central Idaho streams over three years. Biofilm standing crops increased 2–8-fold and incorporated marine-derived nutrients (measured using 15N and 13C) in the month following treatment, but these responses did not persist year-to-year. Biofilms were nitrogen (N) limited before treatments, and remained N limited in analog, but not carcass-treated reaches. Despite these biofilm responses, in the month following treatment total N load was equal to 33–47% of the N added to the treated reaches, and N spiraling measurements suggested that as much as 20%, but more likely 2–3% of added N was taken up by microbes. Design of biologically and cost-effective strategies for nutrient addition will require understanding the rates at which stream microbes take up nutrients and the downstream distance traveled by exported nutrients.

  10. Sensitivity analysis of a pulse nutrient addition technique for estimating nutrient uptake in large streams

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    Laurence Lin; J.R. Webster

    2012-01-01

    The constant nutrient addition technique has been used extensively to measure nutrient uptake in streams. However, this technique is impractical for large streams, and the pulse nutrient addition (PNA) has been suggested as an alternative. We developed a computer model to simulate Monod kinetics nutrient uptake in large rivers and used this model to evaluate the...

  11. Characterization of the Kootenai River Algae Community and Primary Productivity Before and After Experimental Nutrient Addition, 2004–2007 [Chapter 2, Kootenai River Algal Community Characterization, 2009 KTOI REPORT].

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    Holderman, Charlie [Kootenai Tribe of Idaho; Bonners Ferry, ID; Anders, Paul [Cramer Fish Sciences; Moscow, ID; Shafii, Bahman [Statistical Consulting Services; Clarkston, WA

    2009-07-01

    The Kootenai River ecosystem (spelled Kootenay in Canada) has experienced numerous ecological changes since the early 1900s. Some of the largest impacts to habitat, biological communities, and ecological function resulted from levee construction along the 120 km of river upstream from Kootenay Lake, completed by the 1950s, and the construction and operation of Libby Dam on the river near Libby Montana, completed in 1972. Levee construction isolated tens of thousands of hectares of historic functioning floodplain habitat from the river channel downstream in Idaho and British Columbia (B.C.) severely reducing natural biological productivity and habitat diversity crucial to large river-floodplain ecosystem function. Libby Dam greatly reduces sediment and nutrient transport to downstream river reaches, and dam operations cause large changes in the timing, duration, and magnitude of river flows. These and other changes have contributed to the ecological collapse of the post-development Kootenai River ecosystem and its native biological communities. In response to large scale loss of nutrients, experimental nutrient addition was initiated in the North Arm of Kootenay Lake in 1992, in the South Arm of Kootenay Lake in 2004, and in the Kootenai River at the Idaho-Montana border during 2005. This report characterizes baseline chlorophyll concentration and accrual (primary productivity) rates and diatom and algal community composition and ecological metrics in the Kootenai River for four years, one (2004) before, and three (2005 through 2007) after nutrient addition. The study area encompassed a 325 km river reach from the upper Kootenay River at Wardner, B.C. (river kilometer (rkm) 445) downstream through Montana and Idaho to Kootenay Lake in B.C. (rkm 120). Sampling reaches included an unimpounded reach furthest upstream and four reaches downstream from Libby Dam affected by impoundment: two in the canyon reach (one with and one without nutrient addition), a braided reach

  12. Assessing Soil Nutrient Additions through Different Composting ...

    African Journals Online (AJOL)

    Bheema

    Nowadays, the use of earthworms as a composting technique is also gaining popularity. This method is commonly known as vermi-composting (Edwards, 1998), the process by which worms are used to convert organic materials ..... were taken. The experimental design applied was a completely randomized block, with 4 ...

  13. Effects of Salinity and Nutrient Addition on Mangrove Excoecaria agallocha

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    Chen, Yaping; Ye, Yong

    2014-01-01

    Effects of salinity on seed germination and growth of young (1 month old) and old (2-year old) seedlings of Excoecaria agallocha were investigated. Combined effects of salinity and nutrient level were also examined on old seedlings. Seed germination was best at 0 and 5 psu salinity. 15 psu salinity significantly delayed root initiation and decreased final establishment rate. All seeds failed to establish at 25 psu salinity. Young seedlings performed best at 0 and 5 psu, but growth was stunned at 15 psu, and all seedlings died within 90 days at 25 psu. Old seedlings grew best at salinities below 5 psu and they survived the whole cultivation at 25 psu. This indicated that E. agallocha increased salt tolerance over time. Gas exchange was significantly compromised by salinities above 15 psu but evidently promoted by high nutrient. Proline accumulated considerably at high nutrient, and its contents increased from 0 to 15 psu but decreased at 25 psu salinity. Lipid peroxidation was aggravated by increasing salinity beyond 15 psu but markedly alleviated by nutrient addition. These responses indicated that E. agallocha was intolerant to high salinity but it can be greatly enhanced by nutrient addition. PMID:24691495

  14. Effects of enzyme Additive on Nutrient intake, Digestibility and ...

    African Journals Online (AJOL)

    Effects of enzyme Additive on Nutrient intake, Digestibility and Rumen metabolites of yearling Cattle fed Grass-hay based diet. ... Nigerian Journal of Animal Science ... There were no significant differences among other levels of inclusion for total dry matter intake, Crude protein intake and Acid Detergent Fibre intake.

  15. Multitrophic effects of nutrient addition in upland grassland.

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    Fountain, M T; Brown, V K; Gange, A C; Symondson, W O C; Murray, P J

    2008-06-01

    Although the effects of nutrient enhancement on aquatic systems are well documented, the consequences of nutritional supplements on soil food webs are poorly understood, and results of past research examining bottom-up effects are often conflicting. In addition, many studies have failed to separate the effects of nutrient enrichment and the physical effects of adding organic matter. In this field study, we hypothesised that the addition of nitrogen to soil would result in a trophic cascade, through detritivores (Collembola) to predators (spiders), increasing invertebrate numbers and diversity. Nitrogen and lime were added to plots in an upland grassland in a randomised block design. Populations of Collembola and spiders were sampled by means of pitfall traps and identified to species. Seventeen species of Collembola were identified from the nitrogen plus lime (N+L) and control plots. Species assemblage, diversity, richness, evenness and total number were not affected by nutrient additions. However, there was an increase in the number of Isotomidae juveniles and Parisotoma anglicana trapped in the N+L plots. Of the 44 spider species identified, over 80% were Linyphiidae. An effect on species assemblage from the addition of N+L to the plots was observed on two of the four sampling dates (July 2002 and June 2003). The linyphiid, Oedothorax retusus, was the only species significantly affected by the treatments and was more likely to be trapped in the control plots.The increased number of juvenile Collembola, and change in community composition of spiders, were consequences of the bottom-up effect caused by nutrient inputs. However, despite efforts to eliminate the indirect effects of nutrient inputs, a reduction in soil moisture in the N+L plots cannot be eliminated as a cause of the invertebrate population changes observed. Even so, this experiment was not confounded by the physical effects of habitat structure reported in most previous studies. It provides evidence

  16. Effects of Roundup formulations, nutrient addition, and Western mosquitofish (Gambusia affinis) on aquatic communities.

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    Geyer, Rebecca L; Smith, Geoffrey R; Rettig, Jessica E

    2016-06-01

    Aquatic communities can be affected by herbicides, nutrient addition, and non-native fish species. We conducted a mesocosm experiment to examine the direct and interactive effects of three stressors: (1) Roundup formulations (Roundup Weed and Grass Killer(®) and Roundup Poison Ivy and Tough Brush Killer Plus(®)), (2) nutrient addition, and (3) the presence of the non-native Western mosquitofish (Gambusia affinis), on experimental pond communities. Roundup formulations had the most widespread effects on the zooplankton community, but effects varied between formulations and among taxa. The only significant effect of nutrient addition was a lowering of Daphnia abundance in the nutrient addition treatments. The abundances of Daphnia, mid-sized cladocerans, and total zooplankton were lowered by mosquitofish, but no other taxa showed significant mosquitofish effects. We found several two-way and three-way interactions among the stressors, but these varied among zooplankton taxa. Chlorophyll a levels were higher with nutrient addition but were not significantly affected by Roundup formulation or mosquitofish. Our results suggest toxicity of Roundup formulations varies among taxa, and Roundup formulations differ in their toxicity to zooplankton, but with no cascading effects on primary producers. In addition, interactions among stressors affected the zooplankton community.

  17. Spatially variable synergistic effects of disturbance and additional nutrients on kelp recruitment and recovery.

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    Carnell, Paul E; Keough, Michael J

    2014-05-01

    Understanding the impact of multiple stressors on ecosystems is of pronounced importance, particularly when one or more of those stressors is anthropogenic. Here we investigated the role of physical disturbance and increased nutrients on reefs dominated by the canopy-forming kelp Ecklonia radiata. We combined experimental kelp canopy removals and additional nutrient at three different locations in a large embayment in temperate southeastern Australia. Over the following winter recruitment season, Ecklonia recruitment was unaffected by increased nutrients alone, but tripled at all sites where the canopy had been removed. At one site, the combination of disturbance and increased nutrients resulted in more than four times the recruitment of the introduced kelp Undaria pinnatifida. Six months after disturbance, the proliferation of the Undaria canopy in the canopy-removal and nutrient-addition treatment negatively influenced the recovery of the native kelp Ecklonia. Given the otherwise competitive dominance of adult Ecklonia, this provides a mechanism whereby Undaria could maintain open space for the following recruitment season. This interplay between disturbance, nutrients and the response of native and invasive species makes a compelling case for how a combination of factors can influence species dynamics.

  18. Grassland productivity in response to nutrient additions and herbivory is scale-dependent

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    Erica A.H. Smithwick

    2016-12-01

    Full Text Available Vegetation response to nutrient addition can vary across space, yet studies that explicitly incorporate spatial pattern into experimental approaches are rare. To explore whether there are unique spatial scales (grains at which grass response to nutrients and herbivory is best expressed, we imposed a large (∼3.75 ha experiment in a South African coastal grassland ecosystem. In two of six 60 × 60 m grassland plots, we imposed a scaled sampling design in which fertilizer was added in replicated sub-plots (1 × 1 m, 2 × 2 m, and 4 × 4 m. The remaining plots either received no additions or were fertilized evenly across the entire area. Three of the six plots were fenced to exclude herbivory. We calculated empirical semivariograms for all plots one year following nutrient additions to determine whether the scale of grass response (biomass and nutrient concentrations corresponded to the scale of the sub-plot additions and compared these results to reference plots (unfertilized or unscaled and to plots with and without herbivory. We compared empirical semivariogram parameters to parameters from semivariograms derived from a set of simulated landscapes (neutral models. Empirical semivariograms showed spatial structure in plots that received multi-scaled nutrient additions, particularly at the 2 × 2 m grain. The level of biomass response was predicted by foliar P concentration and, to a lesser extent, N, with the treatment effect of herbivory having a minimal influence. Neutral models confirmed the length scale of the biomass response and indicated few differences due to herbivory. Overall, we conclude that interpretation of nutrient limitation in grasslands is dependent on the grain used to measure grass response and that herbivory had a secondary effect.

  19. Evaluation of nutrient addition to diesel biodegradation | Singh ...

    African Journals Online (AJOL)

    The breakdown of hydrocarbon C> 16 were relatively faster than the shorter chain compounds such as C9. In conclusion, the supplementation of fertilizer stimulates the diesel degradation rate in the contaminated soil and the effects of nutrient supplementation are dependant upon soil types, existing nutrients and microbial ...

  20. Growth and nutrient uptake of coffee seedlings cultivated in nutrient solution with and without silicon addition

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    Ana Catarina Monteiro Carvalho Mori da Cunha

    2012-06-01

    Full Text Available In recent years, the application of silicon (Si in crops, including coffee, has become a common practice. The objective of this study was to assess the silicon uptake by coffee seedlings and its effects on plant growth, water and macro and micronutrient uptake. The research was conducted using nutrient solution in a greenhouse at the Departamento de Fitotecnia da Universidade Federal de Viçosa, in a completely randomized design with two treatments (with and without silicon and three replications. Each plot consisted of three plants grown in a 800 mL vessel containing the treatment solutions. At every three days, water consumption, the concentration of OH - and the depletion of Si and K were assessed in the nutrient solutions. After 33 days, the plants were assessed with regard to their fresh and dry weight of leaves, roots and stem, shoot height and total length of the plant (shoot and root. Number of leaves and internodes, and the content and accumulation of silicon, macro, and micronutrients were also determined. The consumption of water, the amount of potassium uptake and, biomass accumulation were greater in plants grown in solution without silicon addition. However, the concentration of OH- in the solution and the amount of silicon uptake were greater in plants grown in solution with added silicon. Silicon accumulation was greater in leaves than in stem and roots. Silicon decreased coffee plant accumulation of phosphorus, potassium, calcium, zinc, copper and iron.

  1. A precision nutrient variability study of an experimental plot in ...

    African Journals Online (AJOL)

    The spatial soil fertility status of a 2.5 ha experimental plot was generated by mapping the soil nutrient concentration and fertility status using GIS kriging technique. The research was conducted in Mukono Zonal Agricultural Research and Development Institute, Mukono, Uganda in October 2013. Soil samples across the ...

  2. Mycorrhizal effects on nutrient cycling, nutrient leaching and N2O production in experimental grassland

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    Bender, S.F.; Conen, F.; van der Heijden, M.G.A.

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) can enhance plant nutrition and growth. However, their contribution to nutrient cycling in ecosystems is still poorly understood. Using experimental grassland microcosms filled with two different soil types (pasture and heath soil) and fertilized with different N

  3. Effect of two natural light regimes and nutrient addition on the forest herb Begonia decandra (Begoniaceae).

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    Cordero, R A

    2000-01-01

    The effect of two natural light-growing conditions (understory versus light gaps) and the interaction with nutrient availability (through fertilization) were studied in the understory herb Begonia decandra, in the Luquillo Experimental Forest in Puerto Rico. Sixteen potted plants obtained from cuttings were randomly chosen and distributed in each of eighth forest environments (four light gaps and four understories), for a total of 128 plants. Fertilizer was applied to half of the plants in each site. After seven months in the two given microenvironments, increased light and fertilization resulted in greater growth and some changes in the biomass allocation patterns. All measured variables responded similarly to reported changes for tree seedlings and saplings from other tropical and subtropical regions. Total growth parameters (height, biomass and leaf area) were very sensitive to increases in the main resource (light). The addition of nutrients was less important in producing changes in the allocation variables (root to shoot ratio, leaf area ratio, and specific leaf mass) under conditions of high light availability. Changes due to nutrient levels were relatively greater on plants grown under under-story conditions. Also, small light differences among sites can cause significant changes in the variables related to total growth. Lastly, plant mortality in the nutrient treatments was found to be independent of mortality in two forest light environments. Some hypotheses about resource acquisition and plant growth are not supported by this data.

  4. Optimizing simulated fertilizer additions using a genetic algorithm with a nutrient uptake model

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    Wendell P. Cropper; N.B. Comerford

    2005-01-01

    Intensive management of pine plantations in the southeastern coastal plain typically involves weed and pest control, and the addition of fertilizer to meet the high nutrient demand of rapidly growing pines. In this study we coupled a mechanistic nutrient uptake model (SSAND, soil supply and nutrient demand) with a genetic algorithm (GA) in order to estimate the minimum...

  5. Can uptake length in strams be determined by nutrient addition experiments? Results from an interbiome comparison study

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    P. J Mulholland; J. L. Tanks; J. R. Webster; W. B. Bowden; W. K Dodds; S. V. Gregory; N. B Grimm; J. L. Meriam; J. L. Meyer; B. J. Peterson; H. M. Valett; W. M. Wollheim

    2002-01-01

    Nutrient uptake length is an important parnmeter tor quantifying nutrient cycling in streams. Although nutrient tracer additions are the preierred method for measuring uptake length under ambient nutrient concentrations, short-term nutrient addition experiments have more irequently been used to estimate uptake length in streams. Theoretical analysis of the relationship...

  6. Soil bacterial communities respond to mowing and nutrient addition in a steppe ecosystem.

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    Ximei Zhang

    Full Text Available In many grassland ecosystems, nitrogen (N and phosphorus (P are added to improve plant productivity, and the aboveground plant biomass is mowed and stored as hay for the bullamacow. Nutrient addition and mowing affect the biodiversity and ecosystem functioning, and most of the previous studies have primarily focused on their effects on macro-organisms, neglecting the responses of soil microbial communities. In this study, we examined the changes in three community attributes (abundance, richness, and composition of the entire bacterial kingdom and 16 dominant bacterial phyla/classes in response to mowing, N addition, P addition, and their combinations, by conducting a 5-year experiment in a steppe ecosystem in Inner Mongolia, China. Overall, N addition had a greater effect than mowing and P addition on most of these bacterial groups, as indicated by changes in the abundance, richness and composition in response to these treatments. N addition affected these soil bacterial groups primarily through reducing soil pH and increasing available N content. Meanwhile, the 16 bacterial phyla/classes responded differentially to these experimental treatments, with Acidobacteria, Acidimicrobidae, Deltaproteobacteria, and Gammaproteobacteria being the most sensitive. The changes in the abundance, richness, and composition of various bacterial groups could imply some potential shift in their ecosystem functions. Furthermore, the important role of decreased soil pH caused by N addition in affecting soil bacterial communities suggests the importance of restoring acidified soil to maintain soil bacterial diversity.

  7. Improvement of aquaponic performance through micro- and macro-nutrient addition.

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    Ru, Dongyun; Liu, Jikai; Hu, Zhen; Zou, Yina; Jiang, Liping; Cheng, Xiaodian; Lv, Zhenting

    2017-07-01

    Aquaponics is one of the "zero waste" industry in the twenty-first century, and is considered to be one of the major trends for the future development of agriculture. However, the low nitrogen utilization efficiency (NUE) restricted its widely application. To date, many attempts have been conducted to improve its NUE. In the present study, effect of micro- and macro-nutrient addition on performance of tilapia-pak choi aquaponics was investigated. Results showed that the addition of micro- and macro-nutrients improved the growth of plant directly and facilitated fish physiology indirectly, which subsequently increased NUE of aquaponics from 40.42 to 50.64%. In addition, remarkable lower total phosphorus concentration was obtained in aquaponics with micro- and macro-nutrient addition, which was attributed to the formation of struvite. Most of the added micro-nutrients were enriched in plant root, while macro-nutrients mainly existed in water. Moreover, no enrichment of micro- and macro-nutrients in aquaponic products (i.e., fish and plant leaves) was observed, indicating that it had no influence on food safety. The findings here reported manifest that appropriate addition of micro- and macro-nutrients to aquaponics is necessary, and would improve its economic feasibility.

  8. Relation between selected nutrients in the chicken meat depending on phytogenic feed additives

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    Mária Angelovičová

    2016-05-01

    Full Text Available The aim of study was to evaluate the relation between selected nutrients in the breast and thigh muscles after the application of different phytogenic additives in the diet of broiler chickens and between same indicators of meat disregarding additive and parts of carcass, from which muscles originate. We realized an in vivo experiment on the Zámostie Company poultry test station with deep litter breeding system. The experiment included 100 pcs of one-day-old hybrid chickens Cobb 500 divided into 2 groups (n = 50: the 1st experimental group with an application of feed additive from chestnut tree and lemon fruit extracts and the 2nd experimental group with an application of feed additive from citrus fruits extract. We used a cereal and soybean basal diet and we divided the fattening period into four phases: starter (1 - 10 days, grower I (11 - 20 days, grower II (21 - 28 days and finisher (29 - 42 days. We applied a powder form feed mixtures. Nutritive value of feed mixtures was the same in each experimental group during the whole experiment and in accordance with the physiological needs of broiler chickens. We fed the 1st experimental group with a basal diet enriched by feed additive from chestnut tree and lemon fruit extracts (50 g/100 kg. As for the 2nd experimental group, we applied feed additive from citrus fruits extracts through the drinking water (100 mL/100 L. In the 2nd part of our experiment, we compared results obtained from two experimental groups with other four groups of diet. We applied other phytogenic additives to these four groups and we did not take into account the origin of the meat sample. We measured indicators of the chemical composition of protein, fat, water and cholesterol on a sample (50 g of breast and thigh muscle without skin by the method of FT IR by use of the apparatus Nicolet 6700. Detected relations between nutrients of breast and thigh muscles were defined by correlation coefficient of -0.6 ≤ r ≥ +0

  9. Experimental evidence for enhanced top-down control of freshwater macrophytes with nutrient enrichment.

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    Bakker, Elisabeth S; Nolet, Bart A

    2014-11-01

    The abundance of primary producers is controlled by bottom-up and top-down forces. Despite the fact that there is consensus that the abundance of freshwater macrophytes is strongly influenced by the availability of resources for plant growth, the importance of top-down control by vertebrate consumers is debated, because field studies yield contrasting results. We hypothesized that these bottom-up and top-down forces may interact, and that consumer impact on macrophyte abundance depends on the nutrient status of the water body. To test this hypothesis, experimental ponds with submerged vegetation containing a mixture of species were subjected to a fertilization treatment and we introduced consumers (mallard ducks, for 8 days) on half of the ponds in a full factorial design. Over the whole 66-day experiment fertilized ponds became dominated by Elodea nuttallii and ponds without extra nutrients by Chara globularis. Nutrient addition significantly increased plant N and P concentrations. There was a strong interactive effect of duck presence and pond nutrient status: macrophyte biomass was reduced (by 50%) after the presence of the ducks on fertilized ponds, but not in the unfertilized ponds. We conclude that nutrient availability interacts with top-down control of submerged vegetation. This may be explained by higher plant palatability at higher nutrient levels, either by a higher plant nutrient concentration or by a shift towards dominance of more palatable plant species, resulting in higher consumer pressure. Including nutrient availability may offer a framework to explain part of the contrasting field observations of consumer control of macrophyte abundance.

  10. Recovery of Three Arctic Stream Reaches From Experimental Nutrient Enrichment.

    Science.gov (United States)

    Green, A. C.; Benstead, J. P.; Deegan, L. A.; Peterson, B. J.; Bowden, W. B.; Huryn, A. D.; Slavik, K.; Hershey, A. E.

    2005-05-01

    We examined multi-year patterns in community recovery from experimental low-concentration nutrient (N+P and P only) enrichment in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (USA). Rates of recovery varied among community components and depended on duration of enrichment (2 to 13 consecutive growing seasons). Biomass and C:P ratio of epilithic algae returned to reference levels rapidly (within 2 years), regardless of enrichment duration. Bryophyte cover, which increased greatly after long-term enrichment (>8 years), recovered to reference levels only after 7 years, when a storm scoured most remnant moss in the recovering reach. Persistence of bryophytes slowed recovery rates of insect taxa that had either been positively (e.g., Ephemerella, most chironomid taxa) or negatively (e.g., Orthocladius rivulorum) affected by this shift in dominant primary producer and its consequence for benthic habitat. Growth of Arctic grayling (adults and young-of-year), the top predator, returned to reference rates within two years. Recovery of these Arctic stream ecosystems from nutrient enrichment was consequently controlled largely by interactions between duration of enrichment and physical disturbance, mediated through physical habitat shifts caused by bryophytes.

  11. Responses of plant nutrient resorption to phosphorus addition in freshwater marsh of Northeast China.

    Science.gov (United States)

    Mao, Rong; Zeng, De-Hui; Zhang, Xin-Hou; Song, Chang-Chun

    2015-01-29

    Anthropogenic activities have increased phosphorus (P) inputs to most aquatic and terrestrial ecosystems. However, the relationship between plant nutrient resorption and P availability is still unclear, and much less is known about the underlying mechanisms. Here, we used a multi-level P addition experiment (0, 1.2, 4.8, and 9.6 g P m(-2) year(-1)) to assess the effect of P enrichment on nutrient resorption at plant organ, species, and community levels in a freshwater marsh of Northeast China. The response of nutrient resorption to P addition generally did not vary with addition rates. Moreover, nutrient resorption exhibited similar responses to P addition across the three hierarchical levels. Specifically, P addition decreased nitrogen (N) resorption proficiency, P resorption efficiency and proficiency, but did not impact N resorption efficiency. In addition, P resorption efficiency and proficiency were linearly related to the ratio of inorganic P to organic P and organic P fraction in mature plant organs, respectively. Our findings suggest that the allocation pattern of plant P between inorganic and organic P fractions is an underlying mechanism controlling P resorption processes, and that P enrichment could strongly influence plant-mediated biogeochemical cycles through altered nutrient resorption in the freshwater wetlands of Northeast China.

  12. Effect of two natural light regimes and nutrient addition on the forest herb Begonia decandra (Begoniaceae

    Directory of Open Access Journals (Sweden)

    Roberto A Cordero S

    2000-06-01

    Full Text Available The effect of two natural light-growing conditions (understory versus light gaps and the interaction with nutrient availability (through fertilization was studied in the understory herb Begonia decandra, in the Luquillo Experimental Forest in Puerto Rico. Sixteen potted plants obtained from cuttings were randomly chosen and distributed in each of eighth forest environments (four light gaps and four understories, for a total of 128 plants. Fertilizer was applied to half of the plants in each site. After seven months in the two given microenvironments, increased light and fertilization resulted in greater growth and some changes in the biomass allocation patterns. All measured variables responded similarly to reported changes for tree seedlings and saplings from other tropical and subtropical regions. Total growth parameters (height, biomass and leaf area were very sensitive to increases in the main resource (light. The addition of nutrients treatments were less important in producing changes in the allocation variables (root to shoot ratio, leaf area ratio, and specific leaf mass under conditions of high light availability. Changes due to nutrient levels were relatively greater on plants grown under understory conditions. Also, small light differences among sites can cause significant changes in the variables related to total growth. Lastly, plant mortality in the nutrient treatments was found to be independent of mortality in two forest light environments. Some hypotheses about resource acquisition and plant growth are not supported by this data.Se estudia el efecto de dos regímenes de luz natural (claros del bosque y el sotobosque y su interacción con la disponibilidad de nutrimentos sobre el crecimiento y la repartición de biomasa de Begonia decandra, una hierba del sotobosque en el Bosque Experimental de Luquillo, Puerto Rico. Dieciseis plantas en macetas obtenidas por estacas se asignaron aleatoriamente a cada uno de los ocho sitios del

  13. Response of nutrients, biofilm, and benthic insects to salmon carcass addition.

    Science.gov (United States)

    Shannon M. Claeson; Judith L. Li; Jana E. Compton; Peter A. Bisson

    2006-01-01

    Salmon carcass addition to streams is expected to increase stream productivity at multiple trophic levels. This study examined stream nutrient (nitrogen, phosphorus, and carbon), epilithic biofilm (ash-free dry mass and chlorophyll a), leaf-litter decomposition, and macroinvertebrate (density and biomass) responses to carcass addition in three headwater streams of...

  14. Joint effects of nutrient addition and enemy exclusion on exotic plant success.

    Science.gov (United States)

    Heckman, Robert W; Wright, Justin P; Mitchell, Charles E

    2016-12-01

    Worldwide, ecosystems are increasingly dominated by exotic plant species, a shift hypothesized to result from numerous ecological factors. Two of these, increased resource availability and enemy release, may act in concert to increase exotic success in plant communities (Resource-Enemy Release Hypothesis, R-ERH). To test this, we manipulated the availability of soil nutrients and access of vertebrate herbivores, insect herbivores, and fungal pathogens to intact grassland communities containing both native and exotic species. Our results supported both conditions necessary for R-ERH. First, exotics were less damaged than natives, experiencing less foliar damage (insect herbivory and fungal disease) than native species, particularly in communities where soil nutrients were added. Second, fertilization increased foliar damage on native species, but not exotic species. As well as fulfilling both conditions for R-ERH, these results demonstrate the importance of considering the effects of resource availability when testing for enemy release. When both conditions are fulfilled, R-ERH predicts that increasing resource availability will increase exotic abundance only in the presence of enemies. Our results fully supported this prediction for vertebrate herbivores: fertilization increased exotic cover only in communities exposed to vertebrate herbivores. Additionally, the prediction was partially supported for insect herbivores and fungal pathogens, excluding these enemies reduced exotic cover as predicted, but inconsistent with R-ERH, this effect occurred only in unfertilized communities. These results highlight the need to consider the influence of multiple enemy guilds on community processes like exotic plant invasions. Moreover, this study experimentally demonstrates that resource availability and natural enemies can jointly influence exotic success in plant communities. © 2016 by the Ecological Society of America.

  15. Effects of nutrient addition on leaf chemistry, morphology, and photosynthetic capacity of three bog shrubs.

    Science.gov (United States)

    Bubier, Jill L; Smith, Rose; Juutinen, Sari; Moore, Tim R; Minocha, Rakesh; Long, Stephanie; Minocha, Subhash

    2011-10-01

    Plants in nutrient-poor environments typically have low foliar nitrogen (N) concentrations, long-lived tissues with leaf traits designed to use nutrients efficiently, and low rates of photosynthesis. We postulated that increasing N availability due to atmospheric deposition would increase photosynthetic capacity, foliar N, and specific leaf area (SLA) of bog shrubs. We measured photosynthesis, foliar chemistry and leaf morphology in three ericaceous shrubs (Vaccinium myrtilloides, Ledum groenlandicum and Chamaedaphne calyculata) in a long-term fertilization experiment at Mer Bleue bog, Ontario, Canada, with a background deposition of 0.8 g N m(-2) a(-1). While biomass and chlorophyll concentrations increased in the highest nutrient treatment for C. calyculata, we found no change in the rates of light-saturated photosynthesis (A(max)), carboxylation (V(cmax)), or SLA with nutrient (N with and without PK) addition, with the exception of a weak positive correlation between foliar N and A(max) for C. calyculata, and higher V(cmax) in L. groenlandicum with low nutrient addition. We found negative correlations between photosynthetic N use efficiency (PNUE) and foliar N, accompanied by a species-specific increase in one or more amino acids, which may be a sign of excess N availability and/or a mechanism to reduce ammonium (NH(4)) toxicity. We also observed a decrease in foliar soluble Ca and Mg concentrations, essential minerals for plant growth, but no change in polyamines, indicators of physiological stress under conditions of high N accumulation. These results suggest that plants adapted to low-nutrient environments do not shift their resource allocation to photosynthetic processes, even after reaching N sufficiency, but instead store the excess N in organic compounds for future use. In the long term, bog species may not be able to take advantage of elevated nutrients, resulting in them being replaced by species that are better adapted to a higher nutrient environment.

  16. Biostimulation of nutrient additions on indigenous microbial community at the stage of nitrogen limitations during composting.

    Science.gov (United States)

    Wang, Huan; Zhao, Yue; Wei, Yuquan; Zhao, Yi; Lu, Qian; Liu, Lina; Jiang, Nan; Wei, Zimin

    2017-12-11

    Microorganisms can play a crucial role in the efficiency for composting, which are essential for converting the organic wastes into a well-stabilized, value added product. However, the activity of most of the key functional microorganisms were inhibited due to the limited special nutrient substances or other physiochemical factors during composting, which further affected the quality of compost. The study was conducted to investigate the effects of enriched ammonium (NH4+-N) and organic nitrogen (Org-N) on indigenous microbial community and whether nitrogen (N) nutrient additions could modify the special species during composting. The results showed that the abundance and structure of bacterial community had distinctly diverse responses to different N nutritional treatments (no nutrient addition, NH4+-N addition, and Org-N addition). The addition of N sources enhanced the abundance of corresponding uncultured indigenous species negatively related to the factor of NH4+ and Org-N in redundancy analysis (RDA) during composting but the effect of NH4+ was more significant than Org-N. Nonmetric multidimensional scaling ordination (NMDS) demonstrated that both the two N additions changed bacterial community but had different duration for affecting bacterial composition. Conclusively, an optimized method for regulating the key stains with special biological capacity is proposed by controlling the single limiting-nutrient factor sharply decreasing at one of composting stages and negatively related to the key species in RDA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Effects of nutrient additions on ecosystem carbon cycle in a Puerto Rican tropical wet forest

    Science.gov (United States)

    YIQING LI; MING XU; XIAOMING ZOU

    2006-01-01

    Wet tropical forests play a critical role in global ecosystem carbon (C) cycle, but C allocation and the response of different C pools to nutrient addition in these forests remain poorly understood. We measured soil organic carbon (SOC), litterfall, root biomass, microbial biomass and soil physical and chemical properties in a wet tropical forest from May 1996 to July...

  18. Thermal induced encapsulation of food nutrients into the phytoferritin through the flexible channels without additives.

    Science.gov (United States)

    Yang, Rui; Tian, Jing; Liu, Yuqian; Yang, Zhiying; Wu, Dandan; Zhou, Zhongkai

    2017-10-16

    The cavity of phytoferritin provides a nano-space to encapsulate and deliver food nutrient molecules. However, tranditional methods to prepare the ferritin-nutrient complexes must undergo acid/alkaline condition or apply additives. In this work, we provide a novel guideline that thermal treatment at 60 °C can expand ferritin channels by uncoiling the surrounding α-helix. Upon reducing the temperature to 20 °C, food nutrient rutin can be encapsulated in the apo-soybean seed ferritin (apoSSF) at pH 7.0 through channels without disassembly of the protein cage and with no addition of additives. Results indicated that one apoSSF could encapsulate about 10.5 molecules of rutin, with an encapsulation ratio of 8.08 % (w/w). In addition, the resulting rutin-loaded SSF complexes were monodispersed in a size of 12 nm in aqueous solution. This work provides a novel pathway for the encapsulation of food nutrient molecules into the nano-cavity of ferritin under a neutral pH condition induced by thermal treatment.

  19. FE, MN and ZN addition to nutrient solutions for tomato and cucumber grown in inert substrates

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2012-01-01

    Abstract: In experiments in a 2×2×3 factorial layout the addition of Fe, Mn and Zn to nutrient solutions for hydroponics was studied with crops grown under greenhouse conditions. Standard as well high concentrations of up to 25 or 50 µmol/L were included as targeted levels in the root environment of

  20. Nutrient additions in pristine Patagonian Sphagnum bog vegetation: can phosphorus addition alleviate (the effects of) increased nitrogen loads.

    Science.gov (United States)

    Fritz, C; van Dijk, G; Smolders, A J P; Pancotto, V A; Elzenga, T J T M; Roelofs, J G M; Grootjans, A P

    2012-05-01

    Sphagnum-bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear whether P-addition can alleviate physiological N-stress in Sphagnum plants. A 3-year fertilisation experiment was conducted in lawns of a pristine Sphagnum magellanicum bog in Patagonia, where competing vascular plants were practically absent. Background wet deposition of nitrogen was low (≈ 0.1-0.2 g · N · m(-2) · year(-1)). Nitrogen (4 g · N · m(-2) · year(-1)) and phosphorus (1 g · P · m(-2) · year(-1)) were applied, separately and in combination, six times during the growing season. P-addition substantially increased biomass production of Sphagnum. Nitrogen and phosphorus changed the morphology of Sphagnum mosses by enhancing height increment, but lowering moss stem density. In contrast to expectations, phosphorus failed to alleviate physiological stress imposed by excess nitrogen (e.g. amino acid accumulation, N-saturation and decline in photosynthetic rates). We conclude that despite improving growth conditions by P-addition, Sphagnum-bog ecosystems remain highly susceptible to nitrogen additions. Increased susceptibility to desiccation by nutrients may even worsen the negative effects of excess nitrogen especially in windy climates like in Patagonia. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  1. Bioremediating Oil Spills in Nutrient Poor Ocean Waters Using Fertilized Clay Mineral Flakes: Some Experimental Constraints

    Directory of Open Access Journals (Sweden)

    Laurence N. Warr

    2013-01-01

    Full Text Available Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98% of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity.

  2. Bioremediating oil spills in nutrient poor ocean waters using fertilized clay mineral flakes: some experimental constraints.

    Science.gov (United States)

    Warr, Laurence N; Friese, André; Schwarz, Florian; Schauer, Frieder; Portier, Ralph J; Basirico, Laura M; Olson, Gregory M

    2013-01-01

    Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98%) of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity.

  3. Multiple stressors in agricultural streams: a mesocosm study of interactions among raised water temperature, sediment addition and nutrient enrichment.

    Directory of Open Access Journals (Sweden)

    Jeremy J Piggott

    Full Text Available Changes to land use affect streams through nutrient enrichment, increased inputs of sediment and, where riparian vegetation has been removed, raised water temperature. We manipulated all three stressors in experimental streamside channels for 30 days and determined the individual and pair-wise combined effects on benthic invertebrate and algal communities and on leaf decay, a measure of ecosystem functioning. We added nutrients (phosphorus+nitrogen; high, intermediate, natural and/or sediment (grain size 0.2 mm; high, intermediate, natural to 18 channels supplied with water from a nearby stream. Temperature was increased by 1.4°C in half the channels, simulating the loss of upstream and adjacent riparian shade. Sediment affected 93% of all biological response variables (either as an individual effect or via an interaction with another stressor generally in a negative manner, while nutrient enrichment affected 59% (mostly positive and raised temperature 59% (mostly positive. More of the algal components of the community responded to stressors acting individually than did invertebrate components, whereas pair-wise stressor interactions were more common in the invertebrate community. Stressors interacted often and in a complex manner, with interactions between sediment and temperature most common. Thus, the negative impact of high sediment on taxon richness of both algae and invertebrates was stronger at raised temperature, further reducing biodiversity. In addition, the decay rate of leaf material (strength loss accelerated with nutrient enrichment at ambient but not at raised temperature. A key implication of our findings for resource managers is that the removal of riparian shading from streams already subjected to high sediment inputs, or land-use changes that increase erosion or nutrient runoff in a landscape without riparian buffers, may have unexpected effects on stream health. We highlight the likely importance of intact or restored buffer

  4. Multiple stressors in agricultural streams: a mesocosm study of interactions among raised water temperature, sediment addition and nutrient enrichment.

    Science.gov (United States)

    Piggott, Jeremy J; Lange, Katharina; Townsend, Colin R; Matthaei, Christoph D

    2012-01-01

    Changes to land use affect streams through nutrient enrichment, increased inputs of sediment and, where riparian vegetation has been removed, raised water temperature. We manipulated all three stressors in experimental streamside channels for 30 days and determined the individual and pair-wise combined effects on benthic invertebrate and algal communities and on leaf decay, a measure of ecosystem functioning. We added nutrients (phosphorus+nitrogen; high, intermediate, natural) and/or sediment (grain size 0.2 mm; high, intermediate, natural) to 18 channels supplied with water from a nearby stream. Temperature was increased by 1.4°C in half the channels, simulating the loss of upstream and adjacent riparian shade. Sediment affected 93% of all biological response variables (either as an individual effect or via an interaction with another stressor) generally in a negative manner, while nutrient enrichment affected 59% (mostly positive) and raised temperature 59% (mostly positive). More of the algal components of the community responded to stressors acting individually than did invertebrate components, whereas pair-wise stressor interactions were more common in the invertebrate community. Stressors interacted often and in a complex manner, with interactions between sediment and temperature most common. Thus, the negative impact of high sediment on taxon richness of both algae and invertebrates was stronger at raised temperature, further reducing biodiversity. In addition, the decay rate of leaf material (strength loss) accelerated with nutrient enrichment at ambient but not at raised temperature. A key implication of our findings for resource managers is that the removal of riparian shading from streams already subjected to high sediment inputs, or land-use changes that increase erosion or nutrient runoff in a landscape without riparian buffers, may have unexpected effects on stream health. We highlight the likely importance of intact or restored buffer strips, both

  5. Nutrient assessment of olive leaf residues processed by solid-state fermentation as an innovative feedstuff additive.

    Science.gov (United States)

    Xie, P-J; Huang, L-X; Zhang, C-H; Zhang, Y-L

    2016-07-01

    Olive leaf residue feedstuff additives were prepared by solid-state fermentation (SSF), and its feeding effects on broiler chickens were examined. The fermentation's nutrient value, that is, protein enrichment, cellulase activity, tannic acid degradation and amino acid enhancement, was determined. The effect of different strains, including molds (Aspergillus niger, Aspergillus oryzae and Trichoderma viride) and yeasts (Candida utilis, Candida tropicalis and Geotrichum candidum), and the fermentation time on the nutrient values of the feedstuff additives was investigated. The experimental results showed that the optimal parameters for best performance were A. niger and C. utilis in a 1 : 1 ratio (v/v) in co-culture fermentation for 5 days. Under these conditions, the total content of amino acids in the fermented olive leaf residues increased by 22·0% in comparison with that in the raw leaf residues. Both Glutamic acid and Aspartic acid contents were increased by more than 25·4%. Broiler chickens fed with different amounts of feedstuff additives were assessed. The results demonstrated that the chicken weight gains increased by 120%, and normal serum biochemical parameters were improved significantly after 10% of the feedstuff additives were supplemented to the daily chicken feed for 28 days. The co-culture combination of A. niger and C. utilis with SSF for olive leaf residue had the best nutrient values. The addition of 10% fermented olive leaf residue facilitated the chicken growth and development. This study reveals that olive leaf residues fermented by SSF exhibited considerable potential as feed additives for feeding poultry. © 2016 The Society for Applied Microbiology.

  6. Additive and interactive effects of nutrient classes on longevity, reproduction, and diet consumption in the Queensland fruit fly (Bactrocera tryoni).

    Science.gov (United States)

    Fanson, Benjamin G; Taylor, Phillip W

    2012-03-01

    Insect lifespan is often closely linked to diet, and diet manipulations have been central to studies of ageing. Recent research has found that lifespan for some flies is maximised on a very low yeast diet, but once all yeast is removed, lifespan drops precipitously. Although effects of yeast availability on lifespan are commonly interpreted in terms of protein, yeast is a complex mix of nutrients and provides a rich source of vitamins, minerals and sterols. Elucidating which components of yeast are involved in this lifespan drop provides insights into more specific nutritional requirements and also provides a test for the commonplace interpretation of yeast in terms of protein. To this end, we fed Queensland fruit flies (Bactrocera tryoni) one of eight experimental diets that differed in the nutrient group(s) found in yeast that were added to sucrose: none, vitamins, minerals, amino acids, cholesterol, vitamin+mineral+cholesterol (VMC), vitamin+mineral+cholesterol+amino acids (VMCA), and yeast. We measured survival rates and egg production in single sex and mixed sex cages, as well as nutrient intake of individual flies. We found that the addition of minerals increased lifespan of both male and female flies housed in single sex cages by decreasing baseline mortality. The addition of just amino acids decreased lifespan in female flies; however, when combined with other nutrient groups found in yeast, amino acids increased lifespan by decreasing both baseline mortality and age-specific mortality. Flies on the yeast and VMCA diets were the only ones to show significant egg production. We conclude that the drop in lifespan observed when all yeast is removed is explained by missing micronutrients (vitamins, minerals and cholesterol) as well as the absence of protein in females, whereas minerals alone can explain the pattern for males. These results indicate a need for caution when interpreting effects of dietary yeast as effects of protein. Copyright © 2011 Elsevier

  7. Effects of long-term nutrient additions on Arctic tundra, stream, and lake ecosystems: beyond NPP.

    Science.gov (United States)

    Gough, Laura; Bettez, Neil D; Slavik, Karie A; Bowden, William B; Giblin, Anne E; Kling, George W; Laundre, James A; Shaver, Gaius R

    2016-11-01

    Primary producers form the base of food webs but also affect other ecosystem characteristics, such as habitat structure, light availability, and microclimate. Here, we examine changes caused by 5-30+ years of nutrient addition and resulting increases in net primary productivity (NPP) in tundra, streams, and lakes in northern Alaska. The Arctic provides an important opportunity to examine how ecosystems characterized by low diversity and low productivity respond to release from nutrient limitation. We review how responses of algae and plants affect light availability, perennial biotic structures available for consumers, oxygen levels, and temperature. Sometimes, responses were similar across all three ecosystems; e.g., increased NPP significantly reduced light to the substrate following fertilization. Perennial biotic structures increased in tundra and streams but not in lakes, and provided important new habitat niches for consumers as well as other producers. Oxygen and temperature responses also differed. Life history traits (e.g., longevity) of the primary producers along with the fate of detritus drove the responses and recovery. As global change persists and nutrients become more available in the Arctic and elsewhere, incorporating these factors as response variables will enable better prediction of ecosystem changes and feedbacks in this biome and others.

  8. Food additives, essential nutrients and neurodevelopmental behavioural disorders in children: A brief review.

    Science.gov (United States)

    Buka, Irena; Osornio-Vargas, Alvaro; Clark, Brenda

    2011-08-01

    In recent decades, changing lifestyles in Canadian homes has led to demand for foods with long shelf lives that are cosmetically appealing, palatable, easy to prepare and to consume. Food additives, especially preservatives and artificial colours as well as suboptimal intake of essential nutrients, have been linked to hyperactive behaviours and poor attention in a subgroup of children. Although other risk factors (ie, genetic, etc) for these conditions have received more attention in the scientific literature, the authors believe that there is enough evidence to consider dietary influences as a modifiable risk factor. This would involve raising awareness among clinicians and, subsequently, reviewing food regulatory processes to better protect children in Canada - similar to the regulations recently undertaken by the British Food Standards Agency. Conflicts of interest due to food and medication industry support for organizations advocating for children would need to be resolved by open communication between government regulatory agencies, academia and industry. Canadian parents and children need to be advised to limit unnecessary food additives and consume a diet rich in essential nutrients while more complete relationships are being explored further.

  9. Nutrient and Rainfall Additions Shift Phylogenetically Estimated Traits of Soil Microbial Communities

    Directory of Open Access Journals (Sweden)

    Kelly Gravuer

    2017-07-01

    Full Text Available Microbial traits related to ecological responses and functions could provide a common currency facilitating synthesis and prediction; however, such traits are difficult to measure directly for all taxa in environmental samples. Past efforts to estimate trait values based on phylogenetic relationships have not always distinguished between traits with high and low phylogenetic conservatism, limiting reliability, especially in poorly known environments, such as soil. Using updated reference trees and phylogenetic relationships, we estimated two phylogenetically conserved traits hypothesized to be ecologically important from DNA sequences of the 16S rRNA gene from soil bacterial and archaeal communities. We sampled these communities from an environmental change experiment in California grassland applying factorial addition of late-season precipitation and soil nutrients to multiple soil types for 3 years prior to sampling. Estimated traits were rRNA gene copy number, which contributes to how rapidly a microbe can respond to an increase in resources and may be related to its maximum growth rate, and genome size, which suggests the breadth of environmental and substrate conditions in which a microbe can thrive. Nutrient addition increased community-weighted mean estimated rRNA gene copy number and marginally increased estimated genome size, whereas precipitation addition decreased these community means for both estimated traits. The effects of both treatments on both traits were associated with soil properties, such as ammonium, available phosphorus, and pH. Estimated trait responses within several phyla were opposite to the community mean response, indicating that microbial responses, although largely consistent among soil types, were not uniform across the tree of life. Our results show that phylogenetic estimation of microbial traits can provide insight into how microbial ecological strategies interact with environmental changes. The method could

  10. Nutrient addition effects on tropical dry forests: a mini-review from microbial to ecosystem scales

    Directory of Open Access Journals (Sweden)

    Jennifer S. Powers

    2015-06-01

    Full Text Available Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales in tropical dry forests. The effects of N and P addition on ecosystem carbon cycling and plant and microbial dynamics depend on forest successional stage, soil parent material and rainfall regime. Responses may depend on whether overall productivity is N- versus P-limited, although data to test this hypothesis are limited. These results highlight the many important gaps in our understanding of tropical dry forest responses to global change. Large-scale experiments are required to resolve these uncertainties.

  11. Nutrient addition effects on tropical dry forests: a mini-review from microbial to ecosystem scales

    Science.gov (United States)

    Powers, Jennifer; Becklund, Kristen; Gei, Maria; Iyengar, Siddarth; Meyer, Rebecca; O'Connell, Christine; Schilling, Erik; Smith, Christina; Waring, Bonnie; Werden, Leland

    2015-06-01

    Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales in tropical dry forests. The effects of N and P addition on ecosystem carbon cycling and plant and microbial dynamics depend on forest successional stage, soil parent material and rainfall regime. Responses may depend on whether overall productivity is N- versus P-limited, although data to test this hypothesis are limited. These results highlight the many important gaps in our understanding of tropical dry forest responses to global change. Large-scale experiments are required to resolve these uncertainties.

  12. [Impact of microbial aggregating agents on soil aggregate stability under addition of exogenous nutrients].

    Science.gov (United States)

    Mo, Yan-Hua; Tang, Jia; Zhang, Ren-Duo; Li, Fang-Zhou

    2012-03-01

    In this study, we investigated the effects of biological aggregating agents (fungal hyphae and microbial extracellular polysaccharides) soil aggregate (with different sizes) stability under addition of exogenous nutrients. The exogenous nutrients included glucose and ammonium nitrate. Experiments were conducted in a 30 d incubation period with three treatments: (1) the control (0.5 mg x g(-1) soil); (2) CN5 (0.5 mg x g(-1) soil, 0.1 mg x g(-1) soil, C/N = 5); (3) CN10 (0.5 mg x g(-1) soil, 0.05 mg x g(-1) soil, C/N = 10). Results showed that soil respiration rates were not significantly different among the three treatments, with maximums being about 3.10 mg x (h x kg)(-1), indicating that the impact of inorganic nitrogen fertilizer was not obvious in a short term. Aside from 5 d, macroaggregates amount of CK (15.67%) was observably lower than those of CN5 (25.32%) and CN10 (24.63%), there were no remarkable discrepancies among 3 treatments in other incubation period. The insignificant difference in the aggregate amounts among the three treatments suggested that the influence of glucose on microbial activities surpassed the inorganic nitrogen fertilizer in shortterm in the study.

  13. Nutrient additions in pristine Patagonian Sphagnum bog vegetation : can phosphorus addition alleviate (the effects of) increased nitrogen loads

    NARCIS (Netherlands)

    Fritz, C.; Dijk, G. van; Smolders, A.J.P.; Pancotto, V.A.; Elzenga, J.T.M.; Roelofs, J.G.M.; Grootjans, A.P.

    Sphagnum-bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear

  14. Nutrient enrichment and food web composition affect ecosystem metabolism in an experimental seagrass habitat.

    Directory of Open Access Journals (Sweden)

    Amanda C Spivak

    Full Text Available BACKGROUND: Food web composition and resource levels can influence ecosystem properties such as productivity and elemental cycles. In particular, herbivores occupy a central place in food webs as the species richness and composition of this trophic level may simultaneously influence the transmission of resource and predator effects to higher and lower trophic levels, respectively. Yet, these interactions are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Using an experimental seagrass mesocosm system, we factorially manipulated water column nutrient concentrations, food chain length, and diversity of crustacean grazers to address two questions: (1 Does food web composition modulate the effects of nutrient enrichment on plant and grazer biomasses and stoichiometry? (2 Do ecosystem fluxes of dissolved oxygen and nutrients more closely reflect above-ground biomass and community structure or sediment processes? Nutrient enrichment and grazer presence generally had strong effects on biomass accumulation, stoichiometry, and ecosystem fluxes, whereas predator effects were weaker or absent. Nutrient enrichment had little effect on producer biomass or net ecosystem production but strongly increased seagrass nutrient content, ecosystem flux rates, and grazer secondary production, suggesting that enhanced production was efficiently transferred from producers to herbivores. Gross ecosystem production (oxygen evolution correlated positively with above-ground plant biomass, whereas inorganic nutrient fluxes were unrelated to plant or grazer biomasses, suggesting dominance by sediment microbial processes. Finally, grazer richness significantly stabilized ecosystem processes, as predators decreased ecosystem production and respiration only in the zero- and one- species grazer treatments. CONCLUSIONS/SIGNIFICANCE: Overall, our results indicate that consumer presence and species composition strongly influence ecosystem responses to nutrient enrichment, and

  15. Experimental evidence of the effect of nutrient enrichment on the zooplankton in a Brazilian coastal lagoon

    Directory of Open Access Journals (Sweden)

    B. KOZLOWSKY-SUZUKI

    Full Text Available Non-treated sewage disposal is one of the main impacts to which Imboassica Lagoon has been subjected. The aim of this study was to evaluate the effect of a potential increase in the artificial enrichment on the environmental conditions and zooplankton of this system. To this end, an experimental study was conducted in mesocosms where nutrients were added daily. Bacterial numbers, chlorophyll-a, and picoplanktonic cyanobacteria densities showed an increase with the availability of nutrients. Bacterio- and phytoplankton seemed to be regulated by the rotifers Brachionus rotundiformis and Hexarthra brandorffi.

  16. Reducing Nutrients to San Francisco Bay through Additional Wastewater Sidestream Treatment Project

    Science.gov (United States)

    Information about the SFBWQP Reducing Nutrients to San Francisco Bay Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  17. Nutrient addition differentially affects ecological processes of Avicennia germinans in nitrogen versus phosphorus limited mangrove ecosystems

    Science.gov (United States)

    Feller, Ilka C.; Lovelock, C.E.; McKee, K.L.

    2007-01-01

    Nutrient over-enrichment is a major threat to marine environments, but system-specific attributes of coastal ecosystems may result in differences in their sensitivity and susceptibility to eutrophication. We used fertilization experiments in nitrogen (N)- and phosphorus (P)-limited mangrove forests to test the hypothesis that alleviating different kinds of nutrient limitation may have different effects on ecosystem structure and function in natural systems. We compared a broad range of ecological processes to determine if these systems have different thresholds where shifts might occur in nutrient limitation. Growth responses indicated N limitation in Avicennia germinans (black mangrove) forests in the Indian River Lagoon (IRL), Florida, and P limitation at Twin Cays, Belize. When nutrient deficiency was relieved, A. germinans grew out of its stunted form by increasing wood relative to leaf biomass and shoot length relative to lateral growth. At the P-limited site, P enrichment (+P) increased specific leaf area, N resorption, and P uptake, but had no effect on P resorption. At the N-limited site, +N increased both N and P resorption, but did not alter biomass allocation. Herbivory was greater at the P-limited site and was unaffected by +P, whereas +N led to increased herbivory at the N-limited site. The responses to nutrient enrichment depended on the ecological process and limiting nutrient and suggested that N- versus P-limited mangroves do have different thresholds. +P had a greater effect on more ecological processes at Twin Cays than did +N at the IRL, which indicated that the P-limited site was more sensitive to nutrient loading. Because of this sensitivity, eutrophication is more likely to cause a shift in nutrient limitation at P-limited Twin Cays than N-limited IRL. ?? 2007 Springer Science+Business Media, LLC.

  18. Acumulação de nutrientes em solos arenosos adubados com esterco bovino Nutrient build up in sandy soils receiving manure additions

    Directory of Open Access Journals (Sweden)

    Sandra Regina da Silva Galvão

    2008-01-01

    Full Text Available Os objetivos deste trabalho foram quantificar as concentrações de carbono e nutrientes em solos de áreas adubadas e não adubadas com esterco; quantificar as concentrações de nutrientes em amostras de esterco bovino utilizado na região e calcular o acúmulo de nutrientes resultantes dessa adubação e o potencial de perdas por lixiviação. Foram amostradas 18 áreas agrícolas, com adição anual de esterco por pelo menos dois anos e, como controle, quatro áreas sob pastagem não adubadas, coletando-se amostras de solo das camadas de 0-20, 20-40 e 40-60 cm, que foram analisadas quanto à granulometria, densidade do solo, pH, C, N e P totais, bases trocáveis, P extraível por água e por Mehlich-1. Amostras de esterco utilizadas em nove áreas também foram analisadas. A aplicação de esterco resultou em acumulações médias ao redor de 20 Mg ha-1 de C, 2 Mg ha-1 de N total e Ca, e de 0,5 a 1 Mg ha-1 de P total, K e Mg (0-60 cm. Acumulações de P solúvel em água e bases trocáveis na camada de 40-60 cm, em relação às testemunhas, indicam grande potencial de perda desses nutrientes.The objective of this work was to quantify changes on carbon and nutrient contents in soils under continuous manure additions. Eighteen cropped fields that had received annual additions of manure for at least two years and four fields under pasture with no history of manure addition were sampled to assess if this practice results in the accumulation or losses of added nutrients. Soils samples from the 0-20, 20-40 and 40-60 cm layers were taken from each field, and analyzed with regard to their physical (particle size and soil density and chemical (pH, total C, N and P, extractable P by Mehlich-1 and water, and exchangeable cations properties. Manure samples used in nine fields were also analyzed for chemical composition. Manure additions resulted in a build up of nutrient stocks near to 20 Mg ha-1 of C, 2 Mg ha-1 of N and Ca, and 0.5 to 1 Mg ha-1 of P

  19. Controlling Non-additional Credits from Nutrient Management in Water Quality Trading Programs Through Eligibility Baseline Stringency

    OpenAIRE

    Savage, Jeffrey; Ribaudo, Marc

    2014-01-01

    A concern for any program that offers payment for environmental services is that those services be additional. Non-additional services are those that would have been provided without the payment. One source of non-additionality is farmer misrepresentation of their pre-program management. Farm management practices are often difficult to observe, particularly those that do not involve structural changes, such as nutrient management. If practices are difficult to observe, management oversight la...

  20. On-line monitoring of responses to nutrient feed additions by multi-frequency permittivity measurements in fed-batch cultivations of CHO cells.

    Science.gov (United States)

    Ansorge, Sven; Esteban, Geoffrey; Schmid, Georg

    2010-04-01

    Changes in the nutrient availability of mammalian cell cultures are reflected in the beta-dispersion parameter characteristic frequency (f ( C )) and the on-line dual frequency permittivity signal. Multi-frequency permittivity measurements were therefore evaluated in fed-batch cultivations of two different CHO cell lines. Similar responses to nutrient depletions and discontinuous feed additions were monitored in different cultivation phases and experimental setups. Sudden increases in permittivity and f ( C ) occurred when feed additions were conducted. A constant or declining permittivity value in combination with a decrease in f ( C ) indicated nutrient limitations. f ( C ) correlated well with changes in oxygen uptake rate when cell diameter remained constant, indicating that metabolic activity is reflected in the value of f ( C ). When significant cell size changes occurred during the cultivations, the analysis of the beta-dispersion parameters was rendered complex. For the application of our findings in other systems it will be hence required to conduct additional off-line measurements. Based on these results, it is hypothesized that multi-frequency permittivity measurements can give information on the intracellular or physiological state in fed-batch mode. Similar observations were made when using different cell lines and feeding strategies, indicating that the findings are transferable to other cell lines and systems. The results should lead to an improved understanding of routine fed-batch processes. Additional studies are, however, required to explore how these observations can be used for fed-batch process development and optimization.

  1. Effects of fish and nutrient additions on food-web stability in a charophyte-dominated lake

    NARCIS (Netherlands)

    van de Bund, W.; Van Donk, E.

    2004-01-01

    1. The response of major food-web constituents to combinations of nutrient addition and zooplanktivorous fish abundance was tested during two subsequent years in the shallow charophyte-dominated lake Naardermeer in the Netherlands, using in situ enclosures. 2. Treatment effects differed sharply

  2. Vitamins and nutrients as primary treatments in experimental brain injury: Clinical implications for nutraceutical therapies.

    Science.gov (United States)

    Vonder Haar, Cole; Peterson, Todd C; Martens, Kris M; Hoane, Michael R

    2016-06-01

    With the numerous failures of pharmaceuticals to treat traumatic brain injury in humans, more researchers have become interested in combination therapies. This is largely due to the multimodal nature of damage from injury, which causes excitotoxicity, oxidative stress, edema, neuroinflammation and cell death. Polydrug treatments have the potential to target multiple aspects of the secondary injury cascade, while many previous therapies focused on one particular aspect. Of specific note are vitamins, minerals and nutrients that can be utilized to supplement other therapies. Many of these have low toxicity, are already FDA approved and have minimal interactions with other drugs, making them attractive targets for therapeutics. Over the past 20 years, interest in supplementation and supraphysiologic dosing of nutrients for brain injury has increased and indeed many vitamins and nutrients now have a considerable body of the literature backing their use. Here, we review several of the prominent therapies in the category of nutraceutical treatment for brain injury in experimental models, including vitamins (B2, B3, B6, B9, C, D, E), herbs and traditional medicines (ginseng, Gingko biloba), flavonoids, and other nutrients (magnesium, zinc, carnitine, omega-3 fatty acids). While there is still much work to be done, several of these have strong potential for clinical therapies, particularly with regard to polydrug regimens. This article is part of a Special Issue entitled SI:Brain injury and recovery. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. External Carbon Source Addition as a Means to Control an Activated Sludge Nutrient Removal Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens; Søeberg, Henrik

    1994-01-01

    In alternating type activated sludge nutrient removal processes, the denitrification rate can be limited by the availability of readily-degradable carbon substrate. A control strategy is proposed by which an easily metabolizable COD source is added directly to that point in the process at which...

  4. The use of nutrient addition as a wetland reclamation strategy in the oil sands region of Alberta, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Boutsivongsakd, M.; Farwell, A.; Chen, H.; Heerkens, N.; Warner, B.; Dixon, G. [Waterloo Univ., ON (Canada)

    2007-07-01

    Large volumes of oil sands process-material (OSPM) are generated as a result of mining and extraction of bitumen in Alberta's oil sands region. This paper addressed the challenge of using OSPM to create wetlands. These materials have the potential to strongly affect the rate and type of aquatic faunal and floral colonization. The quality of the substrate in wetlands may be poor due to physical or chemical characteristics. It is best to construct wetlands that promote optimal sedimentation because of the potential chronic effects of polycyclic aromatic compounds (PACs). Nutrient addition is one approach for optimal sedimentation that may quickly confine potentially toxic OSPM used as an initial substrate. This study examined the influence of nutrient addition on plankton and periphyton production. It also investigated the impact of maximum sedimentation on invertebrate and macrophyte colonization. Mesocosms were set up at three different reclamation sites along a gradient of naphthenic acid concentration in the water in order to examine the effects of nutrient addition. Naphthenic acids occur naturally in oil sands and are toxic to aquatic organisms. For each site, mesocosms were lined with mature fine tailings, reclamation soil and sand. Nutrients were added to the mesocosms to create oligotrophic, mesotrophic, and eutrophic conditions for each water treatment. Planktonic and periphytic production and sedimentation were then examined.

  5. Effect of the Feed Additive Clinoptilolite (ZeoFeed on Nutrient Metabolism and Production Performance of Laying Hens

    Directory of Open Access Journals (Sweden)

    Miroslav Macháček

    2010-01-01

    Full Text Available The aim of this study was to assess the effects of two levels of clinoptilolite administered in feed (2% and 4% on some selected performance indicators, metabolic utilization of basic nutrients and the health status of laying hens. The selected 24 Bovans Goldline hybrid laying hens were divided into three equal groups, two experimental groups (E1 and E2 and one control group (C. The laying hens were housed individually in cages with an automatic supply of drinking water, manual feeding, in a setting with controlled light and temperature regimens. Hens from individual groups were all fed a complete feed mix of the same composition and the only difference was in clinoptilolite supplementation: feed mixes for E1 and E2 groups contained 2% and 4% of clinoptilolite (commercial additive ZeoFeed respectively, replacing the same amounts of wheat. The hens received feed mixes and drinking water ad libitum. During this 28-day experiment, feed consumption and the number and weight of eggs laid were monitored individually for each hen. At the end of the experiment, the balance test using the indicator method (Cr2O3 was performed in all eight hens in each of the groups. The results of balance tests were then used to calculate the metabolic utilization of selected nutrients (nitrogen, fat, ash, nitrogen-free extracts, starch, gross energy, Ca, P. After the balance tests, blood samples for haematological and biochemical examinations were collected via puncture of the vena basilica. The addition of 2% clinoptilolite to feed mix resulted in a highly significant (P ⪬ 0.01 increase in mean egg weight to 64.69 g, but the addition of 4% clinoptilolite in group E2 resulted in a highly significant (P ⪬ 0.01 decrease in mean egg weight to 62.20 g compared to the control (63.73 g. Moreover, daily feed mix consumption in group E1 decreased to 114 g per one laying hen/day compared to the controls (118 g per one laying hen/day. In group E2 (4% clinoptilolite, daily

  6. Nutrient addition modifies phosphatase activities along an altitudinal gradient in a tropical montane forest in Southern Ecuador

    Directory of Open Access Journals (Sweden)

    Karla eDietrich

    2016-02-01

    Full Text Available Atmospheric nutrient deposition and climate change are expected to endanger the diversity of tropical forest ecosystems. Nitrogen (N deposition might influence nutrient fluxes beyond the N cycle by a concomitant increased demand for other nutritional elements such as phosphorus (P. Organisms might respond to the increased P demand by enhanced activity of enzymes involved in releasing inorganic P from organic matter (OM. Our aims were to assess the effect of i climate shifts (approximated by an altitudinal gradient, and ii nutrient addition (N, P, N+P on phosphatase activity (PA in organic layer and mineral soil of a tropical montane rainforest in Southern Ecuador. A nutrient manipulation experiment (NUMEX was set up along an altitudinal gradient (1000, 2000, and 3000 m a.s.l.. We determined PA and inorganic and total P concentrations. PA at 1000 m was significantly lower (mean ± standard error: 48 ± 20 µmol p-NP g-1 dm h-1 as compared to 2000 m and 3000 m (119 ± 11 and 137 ± 19, respectively. One explanation might be that very rapid decomposition of OM at 1000 m results in very thin organic layers reducing the stabilization of enzymes and thus, resulting in leaching loss of enzymes under the humid tropical climate. We found no effect of N addition on PA neither in the organic layer nor in mineral soil, probably because of the low nutrient addition rates that showed ambiguous results so far on productivity measures as a proxy for P demand. In the organic layers of P and N+P treatments, we found decreased PA and increased concentrations of inorganic P. This indicates that the surplus of inorganic P reduced the biosynthesis of phosphatase enzymes. PA in megadiverse montane rainforests is likely to be unaffected by increased atmospheric N deposition but reduced upon atmospheric P deposition.

  7. Effects of nutrients enrichment on algal communities: an experimental in mesocosms approach Efeitos do enriquecimento de nutrientes em comunidades de algas: uma abordagem experimental em mesocosmos

    Directory of Open Access Journals (Sweden)

    Sirlene Aparecida Felisberto

    2011-06-01

    Full Text Available AIM: The effect of different concentrations of nutrients on algal communities living at the bottom of mesocosms was examined; METHODS: The experiment was carried out in the tributary of Rosana reservoir (Corvo river from November 22nd to December 16th of 2003. Mesocosms were set up in triplicate, with four treatments: nitrogen (N; phosphorus (P; nitrogen plus phosphorus (NP; plus a control treatment (C, consisting in addition of water from the reservoir; RESULTS: Results of the Principal Components Analysis applied on the abiotic variables have shown that two axes explained 93.6% of the total variability (69.6 and 23.9%, respectively. It was possible to identify a group of P (positive and N (negative treatments of axis 1. The addition of nutrients in the experiment resulted in changes in algal composition. Mean values of density ranged from 8.383 to 34.510 ind.mL-1. Higher densities occurred in the phosphorus and nitrogen plus phosphorus treatments. The most representative classes were Zygnemaphyceae, Chlorophyceae, Bacillariophyceae and Cyanobacteria, both in density and species richness; CONCLUSIONS: Phosphorus seems to be beneficial to green algae in general, since a marked increase in Zygnemaphyceae and Chlorophyceae was found in the treatments containing phosphorus and nitrogen plus phosphorus. In the nitrogen treatment, however, green algae decreased dramatically, while Cyanobacteria remained constant, indicating their capacity to live in changed environments and confirms the limiting role played by phosphorus on the algal groups.OBJETIVO: Este trabalho teve como objetivo avaliar a resposta das comunidades algais presente no sedimento de mesocosmos em diferentes concentrações de nutrientes; MÉTODOS: O experimento foi realizado no afluente do reservatório de Rosana (rio do Corvo no período de 22 de novembro a 16 de dezembro de 2003. Os mesocosmos foram preparados em triplicatas e em quatro tratamentos: (N com adição de nitrog

  8. A Simple Experimental Setup for Teaching Additive Colors with Arduino

    Science.gov (United States)

    Carvalho, Paulo Simeão; Hahn, Marcelo

    2016-01-01

    The result of additive colors is always fascinating to young students. When we teach this topic to 14- to 16-year-old students, they do not usually notice we use maximum light quantities of red (R), green (G), and blue (B) to obtain yellow, magenta, and cyan colors in order to build the well-known additive color diagram of Fig. 1. But how about…

  9. Experimental analysis on the effect of addition of Rhizoma ...

    African Journals Online (AJOL)

    The effect of addition of Rhizoma gastrodiae on mycelia and exopolysaccharide production by submerged culture of Grifola frondosa was investigated. About 7% (v/v) of R. gastrodiae extract was added to the basal medium used for its biomass and exopolysaccharide productions. The biomass and exopolysaccharide ...

  10. Experimentation on bio-kerosene stove using organic additive

    Science.gov (United States)

    Varshini, M.; Shetty, Divakar

    2017-07-01

    One of the basic worthy item used in most of the villages even now a day's also is the kerosene stove. But in the current scenario, the petroleum products are been replenished. So an alternate fuel should be found in order delve. This work is to check the contingency of blending pongamia oil and kerosene in which is used as an additive. Pongamia is one of the forest based fast growing evergreen tree which is capable of yielding 9 - 90 kg seeds from which 25% of oil can be extracted. Distilled cow urine is to be used so that the fuel can be stored for longer time and is odorless. Blends of 10% to 70% neat pongamia oil - kerosene(KEP) and pongamia oil - kerosene with additive(KEPWA) are prepared. The properties such as flash point, fire point and viscosity are determined. The blends are been compared by doing emission test. The blends with additive showed better properties and reducing in emission characteristics compared to neat blends. It is also observed that emission of CO is decreasing with increasing blends.

  11. Anaerobic rotating disc batch reactor nutrient removal process enhanced by volatile fatty acid addition.

    Science.gov (United States)

    Rodziewicz, Joanna; Janczukowicz, Wojciech; Mielcarek, Artur; Filipkowska, Urszula; Kłodowska, Izabella; Ostrowska, Kamila; Duchniewicz, Sylwia

    2015-01-01

    RBC effluent needs further treatment because of water-quality standards requiring low nitrogen and phosphorus concentrations. It may be achieved by using reactors with biomass immobilized on the filling's surface as post-denitrification biofilm reactors. Due to the lack of organic matter in treated wastewater, the introduction of external carbon sources becomes necessary. The new attached growth bioreactor--anaerobic rotating disc batch reactor (ARDBR)--was examined as a post-denitrification reactor. The impact of selected volatile fatty acids on nutrient removal efficiency in an ARDBR was studied. The biofilm was developing on totally submerged discs mounted coaxially on a vertical shaft. Acetic, propionic, butyric and caproic acids were applied. Wastewaters were removed from the reactors after 24-h treatment, together with the excess solids. In the ARDBR tank, there was no biomass in the suspended form at the beginning of the treatment process. Acids with a higher number of carbon atoms (butyric and caproic) were the most efficient in denitrification process. The highest phosphorus removal efficiency was noted in the ARDBR with butyric and propionic acids. The lowest unitary consumption of the external source of carbon in denitrification was recorded for acetic acid, whereas the highest one for caproic acid.

  12. US Geological Survey nutrient preservation experiment : experimental design, statistical analysis, and interpretation of analytical results

    Science.gov (United States)

    Patton, Charles J.; Gilroy, Edward J.

    1999-01-01

    This report describes the experimental details and interprets results from a study conducted by the U.S. Geological Survey (USGS) in 1992 to assess the effect of different sample-processing treatments on the stability of eight nutrient species in samples of surface-, ground-, and municipal-supply water during storage at 4 degrees Celsius for about 30 days. Over a 7-week period, splits of filtered- and whole-water samples from 15 stations in the continental United States were preserved at collection sites with sulfuric acid (U.S. Environmental Protection Agency protocol), mercury (II) chloride (former U.S. Geological Survey protocol), and ASTM (American Society for Testing and Materials) Type I deionized water (control) and then shipped by overnight express to the USGS National Water Quality Laboratory (NWQL). At the NWQL, the eight nutrient species were determined in splits from each of the 15 stations, typically, within 24 hours of collection and at intervals of 3, 7, 14, 22, and 35 days thereafter. Ammonium, nitrate plus nitrite, nitrite, and orthophosphate were determined only in filtered-water splits. Kjeldahl nitrogen and phosphorus were determined in both filtered-water and whole-water splits.

  13. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Science.gov (United States)

    Velescu, Andre; Valarezo, Carlos; Wilcke, Wolfgang

    2016-05-01

    In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM) by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth. In 2007, we established a nutrient manipulation experiment (NUMEX) to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N), 10 kg ha-1 a-1 of phosphorus (P), 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca) in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes. Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC) and dissolved organic nitrogen (DON) concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments. Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N and P

  14. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Directory of Open Access Journals (Sweden)

    Andre eVelescu

    2016-05-01

    Full Text Available In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth.In 2007, we established a nutrient manipulation experiment (NUMEX to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N, 10 kg ha-1 a-1 of phosphorus (P, 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes.Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC and dissolved organic nitrogen (DON concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments.Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N

  15. Nutrient Uptake and Utilization by Fragrant Rosewood (Dalbergia odorifera Seedlings Cultured with Oligosaccharide Addition under Different Lighting Spectra

    Directory of Open Access Journals (Sweden)

    Xiao-Wen Li

    2018-01-01

    Full Text Available Fragrant rosewood (Dalbergia odorifera T.C. Chen is a highly-valued species suffering from vulnerability due to over-development for wood and medicine. In this study, Fragrant rosewood seedlings were cultured with chitosan oligosaccharide (CO addition at rates of 0 and 1/800 (v/v under artificial lightings by 200-W high-pressure sodium (HPS lamps and 280-W light-emitting diode (LED panels for a 15 h daily photoperiod and a natural illumination as the control. The LEDs were designed to emit lights in 85% of red (600–700 nm, 15% of green(500–600 nm, and 5% of blue (400–500 nm. The height of artificial lightings was elevated every five to seven days to keep the mean photosynthetic photon flux density (PPFD of 72–73 µmol m−2 s−1 of artificial lighting at shoot-tips. Seedlings under LED lighting with CO addition had the greatest diameter growth and leaf biomass, as well as the highest nutrient utilization and evaluated quality, while those under HPS lighting had a higher stem sugar concentration but unchanged shoot growth and biomass compared to the control. In conclusion, we recommend Fragrant rosewood seedlings to be cultured with CO addition under LED lighting to efficiently promote synthetic quality and nutrient utilization.

  16. Effects of litter addition and warming on soil carbon, nutrient pools and microbial communities in a subarctic heath ecosystem

    DEFF Research Database (Denmark)

    Rinnan, Riikka; Michelsen, Anders; Jonasson, Sven Evert

    2008-01-01

    Climatic warming leads to the expansion of deciduous shrubs and trees in the Arctic. This leads to higher leaf litter inputs, which together with warming may alter the rate of carbon and nutrient cycling in the arctic ecosystems. We assessed effects of factorial warming and additional litter...... on the soil ecosystem of a subarctic heath in a 7-year-long field experiment. Fine root biomass, dissolved organic carbon (DOC) and total C concentration increased in response to warming, which probably was a result of the increased vegetation cover. Litter addition increased the concentration of inorganic P...... in the uppermost 5 cm soil, while decreasing the pool of total P per unit area of the organic profile and having no significant effects on N concentrations or pools. Microbial biomass C and N were unaffected by the treatments, while the microbial biomass P increased significantly with litter addition. Soil...

  17. Molecular methods to evaluate effects of feed additives and nutrients in poultry gut microflora Metodologias moleculares para avaliar efeitos de aditivos e nutrientes na microflora intestinal das aves

    Directory of Open Access Journals (Sweden)

    Edgar O. Oviedo-Rondón

    2009-07-01

    Full Text Available Intestines of each animal are the niche of a complex and dynamic ecosystem with important effects to the host. The members or final products of this ecosystem influence nutrient digestion, absorption, mucosa metabolism, general physiology, and local and systemic immunological responses of avian hosts. Better understanding of the avian gut microbial ecosystem may lead to improvements on poultry productivity, health, welfare, and reduction of food borne pathogens and the environmental impact of poultry production for a more sustainable industry. Molecular methods of microbial ecology are key tools to gain this knowledge. The objective of this presentation is to outline the basic concepts, applications, advantages, limitations, and evolution of these molecular methods used to study intestinal microbial ecology. The final goal is to stimulate their application in poultry applied research and development of new feed additives. Some practical examples in poultry research will be described to illustrate their relevance to advance in control methods for pathogens, avoid or manage disbiosis or subclinical intestinal diseases, reduce environmental impact, elucidate effects of nutrients in gut mucosa, microflora, and in general to improve poultry performance.O intestino de cada animal é o nicho de um ecossistema complexo e dinâmico com efeitos importantes para o hospedeiro. As comunidades microbianas componentes deste ecossistema e/ou os produtos finais do metabolismo influenciam a digestão e absorção de nutrientes, o metabolismo das mucosas, a fisiologia geral e as respostas imunitárias locais e gerais da ave hospedeira. A melhor compreensão do ecossistema microbiano do intestino das aves pode levar a melhorias na produtividade, saúde, bem estar, e redução de agente patogênicos dos alimentos e do impacto ambiental da produção avícola para uma indústria mais sustentável. Os métodos moleculares da ecologia microbiana são ferramentas chaves

  18. Influence of Anthropogenic Nutrient Additions on Greenhouse Gas Production Rates at Water-soil Interfaces in an Urban Dominated Estuary

    Science.gov (United States)

    Brigham, B. A.; O'Mullan, G. D.; Bird, J. A.

    2014-12-01

    The tidal Hudson River Estuary (HRE) receives significant inputs of readily dissolvable carbon (C) and nitrogen (N) from incomplete wastewater treatment and sewer overflow during storm events associated with NYC and other urban centers. Nutrient deposition may alter C utilization in the estuarine water column, associated sediments and surrounding wetlands. In these anaerobic systems, we hypothesize that microbial activity is limited by the availability of easily-degradable C (not electron acceptors), which acts as a co-metabolite and provides energy for organic matter decomposition. Sporadic transport of highly C enriched storm derived runoff may substantially enhance greenhouse gas (GHG) production rates through the utilization of stored C pools. To test our hypothesis carbon dioxide (CO2) and methane (CH4) process rates (1) were evaluated from soil cores removed from three distinct HRE wetland sites (Saw Mill Creek, Piermont, and Iona Island Marsh(s)) across a salinity gradient and incubated under varying nutrient treatments. Further, CO2 and CH4 surface water effluxes (2) were quantified from multiple river cruises spanning two years at varying distance from nutrient sources associated with NYC. Incubation experiments from wetland soil core experiments demonstrated that readily degradable C but not inorganic N additions stimulated GHG production (200 - 350 ug C g-1 of dry soil day-1) threefold compared to negative controls. The HRE was found to be both a CO2 and CH4 source under all conditions. The greatest GHG efflux (300 - 3000 nmoles C m-2 day-1) was quantified in mid-channel, tributary, and near shore sites in close proximity to NYC which following precipitation events demonstrated 2-20X increased GHG efflux. These results demonstrate that anthropogenic C additions associated with dense urban centers have the potential to enhance anaerobic microbial degradation of organic matter and subsequent GHG production.

  19. Biogeographic differences in soil biota promote invasive grass response to nutrient addition relative to co-occurring species despite lack of belowground enemy release.

    Science.gov (United States)

    Broadbent, Arthur A D; Stevens, Carly J; Ostle, Nicholas J; Orwin, Kate H

    2018-02-05

    Multiple plant species invasions and increases in nutrient availability are pervasive drivers of global environmental change that often co-occur. Many plant invasion studies, however, focus on single-species or single-mechanism invasions, risking an oversimplification of a multifaceted process. Here, we test how biogeographic differences in soil biota, such as belowground enemy release, interact with increases in nutrient availability to influence invasive plant growth. We conducted a greenhouse experiment using three co-occurring invasive grasses and one native grass. We grew species in live and sterilized soil from the invader's native (United Kingdom) and introduced (New Zealand) ranges with a nutrient addition treatment. We found no evidence for belowground enemy release. However, species' responses to nutrients varied, and this depended on soil origin and sterilization. In live soil from the introduced range, the invasive species Lolium perenne L. responded more positively to nutrient addition than co-occurring invasive and native species. In contrast, in live soil from the native range and in sterilized soils, there were no differences in species' responses to nutrients. This suggests that the presence of soil biota from the introduced range allowed L. perenne to capture additional nutrients better than co-occurring species. Considering the globally widespread nature of anthropogenic nutrient additions to ecosystems, this effect could be contributing to a global homogenization of flora and the associated losses in native species diversity.

  20. Nutrient removal in wastewater treatment high rate algal ponds with carbon dioxide addition.

    Science.gov (United States)

    Park, J B K; Craggs, R J

    2011-01-01

    The influence of CO2 addition to high rate algal ponds (HRAPS) on nitrogen removal was investigated using two pilot-scale HRAPs operated with different hydraulic retention times (HRT: 4 and 8 days), and was compared to the nitrogen removal by the 8-day HRT pond before CO2 addition was installed. Nitrogen balances were calculated by partitioning total nitrogen into organic and inorganic nitrogen (NH4+-N and NO3--N), and by separation of the organic nitrogen into particulate (PON) and dissolved organic nitrogen (DON). PON was further divided into algal organic nitrogen (AON) and bacteria organic nitrogen (BON) to investigate nitrogen mass flow in the HRAPS. This research shows that the proportion of algae in the algal/bacterial biomass in the longer 8-day HRT HRAP8d (55.6%) was appreciably lower than that in the shorter 4-day HRT HRAP4d (80.5%) when CO2 was added to control the maximum pH to rates, indicating that the longer 8-day HRT in the summer was detrimental for two reasons: lower algal productivity and increased nitrogen loss through nitrification/denitrification. Overall nitrogen removal of approximately 60% in the HRAPS with CO2 addition was mainly achieved by algal assimilation followed by sedimentation in the settling unit.

  1. Pork carcass injury in slaughterhouse waiting area and nutrient addition in pre-slaughter fasting

    Directory of Open Access Journals (Sweden)

    Tiago G Petrolli

    2017-01-01

    Full Text Available Objective. Two experiments were conducted on a slaughterhouse located in Brazil, which the first aimed at evaluating the injuries on pig skin and carcass resulting from slaughterhouse waiting area management and the second aimed at assessing how glucose (G, sodium bicarbonate (SB and vitamin E (VE added to water during pre-slaughter fasting may affect carcass yield, organ relative weight and pork meat quality characteristics. Materials and methods. First trial included 1000 pigs, which were observed in the slaughterhouse resting area until the moment they entered the stunning process area. In the second trial were used 500 animals distributed on the last pre-slaughter day in a completely randomized design, including ten treatments and ten replicates. The treatments were: water; 50 g/L G; 50 g/L G + 200 mg/L of VE; 75 g/L of G; 75 g/L of G + 200 mg VE; 0.45% SB; 0.45% SB + 200 mg/L of VE; 0.55% SB; 0.55% SB + 200 mg/L of VE; 200 mg/L of VE. Results. Carcass yield and relative organ weight were not affected by treatments. The addition of 0.55% SB + 200 mg VE reduced the final pH of meat, and of 0.45% SB reduced the red pigment intensity. Conclusions. The main occurrences of injuries to the skin and carcass of pigs are due to fights. Also, adding glucose, sodium bicarbonate, and vitamin E to diet did not affect the carcass and viscera yield and meat quality.

  2. Mathematical modeling and experimental validation of Phaeodactylum tricornutum microalgae growth rate with glycerol addition

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Keli Cristiane Correia; Ribeiro, Robert Luis Lara; Santos, Kassiana Ribeiro dos; Mariano, Andre Bellin [Mariano Center for Research and Development of Sustainable Energy (NPDEAS), Curitiba, PR (Brazil); Vargas, Jose Viriato Coelho [Departament of Mechanical Engineering, Federal University of Parana (UFPR) Curitiba, PR (Brazil)

    2010-07-01

    The Brazilian National Program for Bio fuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO{sub 2}. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10{sup th} and 14{sup th} days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. It was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l{sup -1}. In order to compare

  3. Multiple stressors in agricultural streams: a mesocosm study of interactions among raised water temperature, sediment addition and nutrient enrichment

    National Research Council Canada - National Science Library

    Piggott, Jeremy J; Lange, Katharina; Townsend, Colin R; Matthaei, Christoph D

    2012-01-01

    ... to empirical surveys, field experiments and laboratory experiments to unravel their individual and combined effects [5]. Agriculture affects streams worldwide, particularly through nutrient enr...

  4. Effects of Litter Removal and Addition on the Nutrient Mineralization Dynamics in Hyperseasonal Tropical Savannas of the Brazilian Pantanal

    Science.gov (United States)

    Hentz, C. S.; Pinto-Jr, O. B.; Vourlitis, G. L.

    2015-12-01

    The tropical savanna of Brazil (cerrado) is extremely species diverse and it encompasses many different physiognomic features, which are influenced by rainfall, fire, and soil nutrient availability. Plant litter decomposition recycles nutrients to the soil, and in turn, assists plant growth. However the rate at which these nutrients become available to the soil is poorly understood. Thus, a six month field experiment that encompassed the wet and dry seasons was conducted to assess how different quantities of litter inputs affect nutrient (P, N, C, K, Ca, and Mg) availability. It was hypothesized that nutrient mineralization would be significantly influenced by manipulation of the surface litter and that there would be a positive correlation between soil moisture and nutrient mineralization. Initial results indicate that there were significant differences in mineralization over time for all nutrients, except P, supporting our hypothesis of changes in mineralization with soil moisture. However, there were no significant differences between litter treatments and net mineralization rates for all the nutrients tested. Our results indicate that litterpool size has little effect on short-term nutrient mineralization dynamics.

  5. Additive effects due to biochar and endophyte application enable soybean to enhance nutrient uptake and modulate nutritional parameters.

    Science.gov (United States)

    Waqas, Muhammad; Kim, Yoon-Ha; Khan, Abdul Latif; Shahzad, Raheem; Asaf, Sajjad; Hamayun, Muhammad; Kang, Sang-Mo; Khan, Muhammad Aaqil; Lee, In-Jung

    We studied the effects of hardwood-derived biochar (BC) and the phytohormone-producing endophyte Galactomyces geotrichum WLL1 in soybean (Glycine max (L.) Merr.) with respect to basic, macro- and micronutrient uptakes and assimilations, and their subsequent effects on the regulation of functional amino acids, isoflavones, fatty acid composition, total sugar contents, total phenolic contents, and 1,1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity. The assimilation of basic nutrients such as nitrogen was up-regulated, leaving carbon, oxygen, and hydrogen unaffected in BC+G. geotrichum-treated soybean plants. In comparison, the uptakes of macro- and micronutrients fluctuated in the individual or co-application of BC and G. geotrichum in soybean plant organs and rhizospheric substrate. Moreover, the same attribute was recorded for the regulation of functional amino acids, isoflavones, fatty acid composition, total sugar contents, total phenolic contents, and DPPH-scavenging activity. Collectively, these results showed that BC+G. geotrichum-treated soybean yielded better results than did the plants treated with individual applications. It was concluded that BC is an additional nutriment source and that the G. geotrichum acts as a plant biostimulating source and the effects of both are additive towards plant growth promotion. Strategies involving the incorporation of BC and endophytic symbiosis may help achieve eco-friendly agricultural production, thus reducing the excessive use of chemical agents.

  6. Additive effects due to biochar and endophyte application enable soybean to enhance nutrient uptake and modulate nutritional parameters* #

    Science.gov (United States)

    Waqas, Muhammad; Kim, Yoon-Ha; Khan, Abdul Latif; Shahzad, Raheem; Asaf, Sajjad; Hamayun, Muhammad; Kang, Sang-Mo; Khan, Muhammad Aaqil; Lee, In-Jung

    2017-01-01

    We studied the effects of hardwood-derived biochar (BC) and the phytohormone-producing endophyte Galactomyces geotrichum WLL1 in soybean (Glycine max (L.) Merr.) with respect to basic, macro-and micronutrient uptakes and assimilations, and their subsequent effects on the regulation of functional amino acids, isoflavones, fatty acid composition, total sugar contents, total phenolic contents, and 1,1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity. The assimilation of basic nutrients such as nitrogen was up-regulated, leaving carbon, oxygen, and hydrogen unaffected in BC+G. geotrichum-treated soybean plants. In comparison, the uptakes of macro-and micronutrients fluctuated in the individual or co-application of BC and G. geotrichum in soybean plant organs and rhizospheric substrate. Moreover, the same attribute was recorded for the regulation of functional amino acids, isoflavones, fatty acid composition, total sugar contents, total phenolic contents, and DPPH-scavenging activity. Collectively, these results showed that BC+G. geotrichum-treated soybean yielded better results than did the plants treated with individual applications. It was concluded that BC is an additional nutriment source and that the G. geotrichum acts as a plant biostimulating source and the effects of both are additive towards plant growth promotion. Strategies involving the incorporation of BC and endophytic symbiosis may help achieve eco-friendly agricultural production, thus reducing the excessive use of chemical agents. PMID:28124840

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

    Science.gov (United States)

    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

  8. Development of an epiphyte indicator of nutrient enrichment. A critical evaluation of observational and experimental studies

    Science.gov (United States)

    An extensive review of the literature on epiphytes on submerged aquatic vegetation (SAV), primarily seagrasses but including some brackish and freshwater rooted macrophytes, was conducted in order to evaluate the evidence for response of epiphyte metrics to increased nutrients. ...

  9. Modeling the Effect of External Carbon Source Addition under Different Electron Acceptor Conditions in Biological Nutrient Removal Activated Sludge Systems.

    Science.gov (United States)

    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.

  10. Structurally functional changes in the microbiota of nutrient solution with addition of liquid human wastes, used for growing plants in a closed ecological system

    Science.gov (United States)

    Tirranen, L. S.; Borodina, E. V.; Markov, A. A.

    The investigations have proved the dependence of microbial community of nutrient solution development upon the specific conditions of a closed human life-support ecological system: the time of using permanent solution, introduction of additives into the nutrient medium and system gas exchange closure. For the first time, liquid human wastes were introduced into the nutrient solution to increase the mass exchange closure. Correlation analysis revealed the direct dependence between the time of liquid native human excretions introduction into the nutrient solution and the development of organisms participating in nitrogen transformation and growth of microflora potentially dangerous for humans and plants. With the help of correlation analysis it has been determined that particularly close connection exists between the duration of introduction of liquid human wastes and bacteria Escherichia coli, denitrificators, ammonificators and urobacteria. The correlation coefficient for these microbial groups was: r = 0,78. The investigations showed that by the end of experiment the microbial community of nutrient solution fulfilled the role of native urine destructor successfully. Thus, introduction of human native excretions (at 70% substitution of nitrate nitrogen with urine nitrogen) into the nutrient solution used for growing wheat monoculture in a closed ecosystem is possible.

  11. Additional BCAA-enriched nutrient mixture improves the nutritional condition in cirrhotic patients with hypoalbuminemia despite treatment with regular BCAA granules: A pilot study.

    Science.gov (United States)

    Fukui, Aiko; Kawabe, Naoto; Hashimoto, Senju; Murao, Michihito; Nakano, Takuji; Shimazaki, Hiroaki; Kan, Toshiki; Nakaoka, Kazunori; Ohki, Masashi; Takagawa, Yuka; Kamei, Hiroyuki; Yoshioka, Kentaro

    2015-07-01

    To elucidate the effect of adding branched-chain amino acid (BCAA)-enriched nutrient mixtures in cirrhotic patients with hypoalbuminemia despite the use of BCAA granules. A BCAA-enriched nutrient mixture containing 5.6 g of BCAA and 210 kcal was additionally administered in 40 cirrhotic patients with hypoalbuminemia despite their treatment with BCAA granules containing 12 g of BCAA. Laboratory data were assessed at 6 months before beginning additional therapy, at baseline, and at 6 months after baseline. Serum albumin levels significantly decreased from 6 months before baseline (3.14±0.47 g/dL) to baseline (2.83±0.46 g/dL), despite the treatment with BCAA granules (pBCAA-enriched nutrient mixtures increased serum albumin levels of the cirrhotic patients with hypoalbuminemia despite the treatment with BCAA granules and without hepatocellular carcinoma treatment, upper gastrointestinal tract bleeding, or albumin infusion.

  12. Dietary influences on nutrient partitioning and anatomical body composition of growing pigs; modelling and experimental approaches

    NARCIS (Netherlands)

    Halas, V.

    2004-01-01

    Prediction of pig performance from data on nutrient intake and animal properties makes it easier to obtain a better productivity. It provides tools to arrive at desired outputs, or to calculate required inputs. Thus it enables production to be flexible, safe and less erratic. It is to be expected

  13. Studies on the effects of essential-oil-based feed additives on performance, ileal nutrient digestibility, and selected bacterial groups in the gastrointestinal tract of piglets.

    Science.gov (United States)

    Maenner, K; Vahjen, W; Simon, O

    2011-07-01

    The aim of this study was to assess the effects of 2 different phytogenic products on performance, ileal nutrient digestibility, and composition of the intestinal microbiota. The 2 phytogenic products contained different essential oil mixtures (EOM) characterized by either menthol (Mentha arvensis; EOM-M) or cinnamon aldehyde (Cinnamomum aromaticum; EOM-C) as main constituents. Three treatments consisted of control diet without EOM addition and diets supplemented with EOM-M or EOM-C. Reproducibility of the effects was examined in 4 trials with a total of 300 male castrated and female piglets weaned at 25 d of age. The number of pens per treatment in trials I through III were 7, 9, and 9, respectively, for research station conditions, and 10 in trial IV for simulated farm conditions. In research station conditions, the experimental unit consisted of flat deck pens with 2 piglets per pen, whereas it consisted of floor pens with straw bedding with 5 piglets per pen in farm conditions. The feed additives had no effect on feed intake or BW gain. Improvements (P digestibility of CP and of most AA. The effect of EOM-C on these response criteria was intermediate between control and EOM-M. Real-time PCR analysis of the gastrointestinal contents for 7 bacterial groups (Lactobacillus spp., Enterococcus spp., Clostridium coccoides and Clostridium leptum cluster, Escherichia spp., and Escherichia coli toxin estII) indicated no effect of treatments on the gastrointestinal microbiota. It was concluded that EOM-M consistently improved feed efficiency in weaned piglets, and it was associated with improved ileal protein and AA digestibility. In general, however, the effectiveness of EOM as feed additives differs considerably depending on the constituents. © 2011 American Society of Animal Science. All rights reserved.

  14. Experimental additions of aluminum sulfate and ammonium nitrate to in situ mesocosms to reduce cyanobacterial biovolume and microcystin concentration

    Science.gov (United States)

    Harris, Ted D.; Wilhelm, Frank M.; Graham, Jennifer L.; Loftin, Keith A.

    2014-01-01

    Recent studies suggest that nitrogen additions to increase the total nitrogen:total phosphorus (TN:TP) ratio may reduce cyanobacterial biovolume and microcystin concentration in reservoirs. In systems where TP is >100 μg/L, however, nitrogen additions to increase the TN:TP ratio could cause ammonia, nitrate, or nitrite toxicity to terrestrial and aquatic organisms. Reducing phosphorus via aluminum sulfate (alum) may be needed prior to nitrogen additions aimed at increasing the TN:TP ratio. We experimentally tested this sequential management approach in large in situ mesocosms (70.7 m3) to examine effects on cyanobacteria and microcystin concentration. Because alum removes nutrients and most seston from the water column, alum treatment reduced both TN and TP, leaving post-treatment TN:TP ratios similar to pre-treatment ratios. Cyanobacterial biovolume was reduced after alum addition, but the percent composition (i.e., relative) cyanobacterial abundance remained unchanged. A single ammonium nitrate (nitrogen) addition increased the TN:TP ratio 7-fold. After the TN:TP ratio was >50 (by weight), cyanobacterial biovolume and abundance were reduced, and chrysophyte and cryptophyte biovolume and abundance increased compared to the alum treatment. Microcystin was not detectable until the TN:TP ratio was <50. Although both treatments reduced cyanobacteria, only the nitrogen treatment seemed to stimulate energy flow from primary producers to zooplankton, which suggests that combining alum and nitrogen treatments may be a viable in-lake management strategy to reduce cyanobacteria and possibly microcystin concentrations in high-phosphorus systems. Additional studies are needed to define best management practices before combined alum and nitrogen additions are implemented as a reservoir management strategy.

  15. Shrub growth rate and bark responses to soil warming and nutrient addition – A dendroecological approach in a field experiment

    NARCIS (Netherlands)

    Iturrate-Garcia, Maitane; Heijmans, Monique M.P.D.; Schweingruber, Fritz H.; Maximov, Trofim C.; Niklaus, Pascal A.; Schaepman-Strub, Gabriela

    2017-01-01

    Tundra shrubs are slow-growing species limited by low air temperature and scarce nutrient availability. However, shrub expansion has been widely observed in the Arctic during the last decades and attributed to climate warming. Shift in shrub growth, wood structure and abundance affects the

  16. The effects of nutrient concentration, addition of thickeners, and agitation speed on liquid fermentation of Steinernema feltiae

    Science.gov (United States)

    Therefore, this study was aimed at developing a more suitable liquid media for mass production of Steinernema feltiae, by assessing the effects of nutrient concentration, media viscosity, and agitation speed on infective juvenile (IJ) yield. For all the experiments, the base medium contained yeast ...

  17. Effects of nutrient profiling and price changes based on NuVal® scores on food purchasing in an online experimental supermarket.

    Science.gov (United States)

    Epstein, Leonard H; Finkelstein, Eric A; Katz, David L; Jankowiak, Noelle; Pudlewski, Corrin; Paluch, Rocco A

    2016-08-01

    The goal of the present study was to apply experimental economic methods in an online supermarket to examine the effects of nutrient profiling, and differential pricing based on the nutrient profile, on the overall diet quality, energy and macronutrients of the foods purchased, and diet cost. Participants were provided nutrient profiling scores or price adjustments based on nutrient profile scores while completing a hypothetical grocery shopping task. Prices of foods in the top 20 % of nutrient profiling scores were reduced (subsidized) by 25 % while those in the bottom 20 % of scores were increased (taxed) by 25 %. We evaluated the independent and interactive effects of nutrient profiling or price adjustments on overall diet quality of foods purchased as assessed by the NuVal® score, energy and macronutrients purchased and diet cost in a 2×2 factorial design. A large (>10 000 food items) online experimental supermarket in the USA. Seven hundred and eighty-one women. Providing nutrient profiling scores improved overall diet quality of foods purchased. Price changes were associated with an increase in protein purchased, an increase in energy cost, and reduced carbohydrate and protein costs. Price changes and nutrient profiling combined were associated with no unique benefits beyond price changes or nutrient profiling alone. Providing nutrient profile score increased overall NuVal® score without a reduction in energy purchased. Combining nutrient profiling and price changes did not show an overall benefit to diet quality and may be less useful than nutrient profiling alone to consumers who want to increase overall diet quality of foods purchased.

  18. Elevation dependent sensitivity of northern hardwoods to Ca addition at Hubbard Brook Experimental Forest, NH USA

    Science.gov (United States)

    Rakesh Minocha; Stephanie Long; Palaniswamy Thangavel; Subhash C. Minocha; Christopher Eagar; Charles T. Driscoll

    2010-01-01

    Acidic deposition has caused a depletion of calcium (Ca) in the northeastern forest soils. Wollastonite (Ca silicate) was added to watershed 1 (WS1) at the Hubbard Brook Experimental Forest (HBEF) in 1999 to evaluate its effects on various functions of the HBEF ecosystem. The effects of Ca addition on foliar soluble (extractable in 5% HClO4) ions...

  19. Shifts in the phylogenetic structure of arbuscular mycorrhizal fungi in response to experimental nitrogen and carbon dioxide additions.

    Science.gov (United States)

    Mueller, Rebecca C; Bohannan, Brendan J M

    2015-09-01

    Global N inputs and atmospheric CO2 concentrations have increased as a result of human activities, and are predicted to increase along with population growth, with potentially negative effects on biodiversity. Using taxonomic and phylogenetic measures, we examined the response of arbuscular mycorrhizal fungi (AMF) to experimental manipulations of N and CO2 at the Jasper Ridge Global Change Experiment. No significant interactions between N and CO2 were observed, but individual effects of N and CO2 were found. Elevated CO2 resulted in changes in phylogenetic similarity, and a shift to phylogenetic clustering of AMF communities. N addition resulted in higher phylogenetic diversity and evenness, with no shifts in community composition and no significant signal for phylogenetic clustering. N addition resulted in an increase in both available N and the N:P ratio in N-amended plots, which suggests that changing patterns of nutrient limitation could have lead to altered species interactions. These findings suggest that elevated levels of N and CO2 altered patterns of AMF community assembly, with potential effects on ecosystem function.

  20. Light and Nutrient Dependent Responses in Secondary Metabolites of Plantago lanceolata Offspring Are Due to Phenotypic Plasticity in Experimental Grasslands.

    Directory of Open Access Journals (Sweden)

    Annegret Miehe-Steier

    Full Text Available A few studies in the past have shown that plant diversity in terms of species richness and functional composition can modify plant defense chemistry. However, it is not yet clear to what extent genetic differentiation of plant chemotypes or phenotypic plasticity in response to diversity-induced variation in growth conditions or a combination of both is responsible for this pattern. We collected seed families of ribwort plantain (Plantago lanceolata from six-year old experimental grasslands of varying plant diversity (Jena Experiment. The offspring of these seed families was grown under standardized conditions with two levels of light and nutrients. The iridoid glycosides, catalpol and aucubin, and verbascoside, a caffeoyl phenylethanoid glycoside, were measured in roots and shoots. Although offspring of different seed families differed in the tissue concentrations of defensive metabolites, plant diversity in the mothers' environment did not explain the variation in the measured defensive metabolites of P. lanceolata offspring. However secondary metabolite levels in roots and shoots were strongly affected by light and nutrient availability. Highest concentrations of iridoid glycosides and verbascoside were found under high light conditions, and nutrient availability had positive effects on iridoid glycoside concentrations in plants grown under high light conditions. However, verbascoside concentrations decreased under high levels of nutrients irrespective of light. The data from our greenhouse study show that phenotypic plasticity in response to environmental variation rather than genetic differentiation in response to plant community diversity is responsible for variation in secondary metabolite concentrations of P. lanceolata in the six-year old communities of the grassland biodiversity experiment. Due to its large phenotypic plasticity P. lanceolata has the potential for a fast and efficient adjustment to varying environmental conditions in

  1. Light and Nutrient Dependent Responses in Secondary Metabolites of Plantago lanceolata Offspring Are Due to Phenotypic Plasticity in Experimental Grasslands

    Science.gov (United States)

    Miehe-Steier, Annegret; Roscher, Christiane; Reichelt, Michael; Gershenzon, Jonathan; Unsicker, Sybille B.

    2015-01-01

    A few studies in the past have shown that plant diversity in terms of species richness and functional composition can modify plant defense chemistry. However, it is not yet clear to what extent genetic differentiation of plant chemotypes or phenotypic plasticity in response to diversity-induced variation in growth conditions or a combination of both is responsible for this pattern. We collected seed families of ribwort plantain (Plantago lanceolata) from six-year old experimental grasslands of varying plant diversity (Jena Experiment). The offspring of these seed families was grown under standardized conditions with two levels of light and nutrients. The iridoid glycosides, catalpol and aucubin, and verbascoside, a caffeoyl phenylethanoid glycoside, were measured in roots and shoots. Although offspring of different seed families differed in the tissue concentrations of defensive metabolites, plant diversity in the mothers' environment did not explain the variation in the measured defensive metabolites of P. lanceolata offspring. However secondary metabolite levels in roots and shoots were strongly affected by light and nutrient availability. Highest concentrations of iridoid glycosides and verbascoside were found under high light conditions, and nutrient availability had positive effects on iridoid glycoside concentrations in plants grown under high light conditions. However, verbascoside concentrations decreased under high levels of nutrients irrespective of light. The data from our greenhouse study show that phenotypic plasticity in response to environmental variation rather than genetic differentiation in response to plant community diversity is responsible for variation in secondary metabolite concentrations of P. lanceolata in the six-year old communities of the grassland biodiversity experiment. Due to its large phenotypic plasticity P. lanceolata has the potential for a fast and efficient adjustment to varying environmental conditions in plant communities of

  2. Impact of nutrient enrichment and fish introductions on the structure and function of experimental shallow littoral lagoons

    Directory of Open Access Journals (Sweden)

    Oriol Cano-Rocabayera

    2015-12-01

    Full Text Available Mediterranean coastal lagoons are probably one of the most singular and endangered ecosystems worldwide. Common threats to other aquatic ecosystems are nutrient enrichment and species introductions. In shallow and warm areas, the environmental concern may be even exacerbated by an increase in nutrient levels and biotic interactions due to the low water flow, coupled to the temperature-sensitivity of ectotherms’ metabolism and hence ecological processes. Nutrient enrichment can benefit ecosystem productivity when the bottom-up effect of nutrients is counteracted by top-down controllers such as macro-invertebrates and/or fish. This balance can, however, be directly and indirectly disrupted by excessive fertilization and/or the release of exotic species. Ammonia and nitrite has long been considered a water quality hazard but the toxic effects of nitrates are still poorly studied. The present study examined experimentally the multi-trophic impacts of chronic nitrate exposure and/or the invasive eastern mosquitofish (Gambusia holbrooki on the structure and function of shallow littoral lagoons. Specifically, we monitored ecosystem metabolism (primary production and leaf litter decomposition and the community structure of pelagic and benthonic macro-invertebrates during 2 months. Preliminary results show that chronic nitrate pollution and/or G. holbrooki can profoundly alter the structure and function of coastal lagoon ecosystems, and that pelagic and benthonic sub-systems are coupled in response to these anthropogenic stressors. Although the long-term consequences of these findings remain to be examined in detail, this study will increase our mechanistic understanding of how the top-down and bottom-up controllers of aquatic ecosystems are affected by major drivers of global change typified by nitrate pollution and an invasive species.

  3. Short communication: A laboratory study to validate the impact of the addition of Alnus nepalensis leaf litter on carbon and nutrients mineralization in soil

    Directory of Open Access Journals (Sweden)

    GAURAV MISHRA

    2016-04-01

    Full Text Available Abstract. Mishra G, Giri K, Dutta A, Hazarika S and Borgohain P. 2015. A laboratory study to validate the impact of the addition of Alnus nepalensis leaf litter on carbon and nutrients mineralization in soil. Nusantara Bioscience 8: 5-7. Plant litter or residues can be used as soil amendment to maintain the carbon stock and soil fertility. The amount and rate of mineralization depends on biochemical composition of plant litter. Alnus nepalensis (Alder is known for its symbiotic nitrogen fixation and capability to restore fertility of degraded lands. A laboratory incubation experiment was conducted for 60 days under controlled conditions to validate the carbon and nutrients mineralization potential of alder litter. Soil fertility indicators, i.e. soil organic carbon (SOC, available nitrogen (N, available phosphorus (P, and available potassium (K were analyzed using standard procedures. Significant differences were observed in the soil properties after addition of litter. Nutrient composition of alder litter was found superior by providing significantly higher organic matter and helped in better nutrient cycling. Therefore, alder based land use system may be replicated in other degraded lands or areas for productivity enhancement which is important for sustaining biodiversity and soil fertility.

  4. Experimental Investigations on the Effects of Cerium Oxide Nanoparticle Fuel Additives on Biodiesel

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    V. Sajith

    2010-01-01

    Full Text Available This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in the nanoparticle form on the major physicochemical properties and the performance of biodiesel. The physicochemical properties of the base fuel and the modified fuel formed by dispersing the catalyst nanoparticles by ultrasonic agitation are measured using ASTM standard test methods. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Comparisons of the performance of the fuel with and without the additive are also presented. The flash point and the viscosity of biodiesel were found to increase with the inclusion of the cerium oxide nanoparticles. The emission levels of hydrocarbon and NOx are appreciably reduced with the addition of cerium oxide nanoparticles.

  5. Streamwater Chemistry and Nutrient Export During Five Years of Bark Beetle Infestation of Subalpine Watersheds at the Fraser Experimental Forest

    Science.gov (United States)

    Rhoades, C.; Elder, K.; Hubbard, R.; Porth, L.

    2008-12-01

    Forested watersheds of western North America are currently undergoing rapid and extensive canopy mortality caused by a variety of insect species. The mountain pine bark beetle (Dendroctonus ponderosae) began to attack lodgepole pine (Pinus contorta) at the USFS Fraser Experimental Forest in central Colorado in 2002. By 2007, bark beetles had killed 78% of the overstory pine in Fraser research watersheds on average. The hydrologic, climatic, biogeochemical and vegetation records at the Fraser Experimental Forest provide a unique opportunity to quantify the impacts of this widespread, but poorly understood forest disturbance relative to a multi-decade pre-disturbance period. Here we compare seasonal streamwater chemistry and annual nutrient export for the five years since the bark beetle outbreak began with the pre- attack record. Patterns in post-outbreak streamwater biogeochemistry are compared to changes is species composition and proportional loss of overstory basal area for four basins. The influence of the outbreak will depend upon an aggregate of short (i.e. halted overstory water and nutrient use) and longer-term (i.e. altered canopy interception, windthrow, and understory growth) processes, so the hydrologic and biogeochemical implications of current beetle activity will not be fully realized for decades.

  6. Adição de níquel na solução nutritiva para o cultivo de mudas de umbuzeiro Addition of nickel to nutrient solution for cultivating spondias tuberose tree seedlings

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    Orlando Sílvio Caires Neves

    2007-06-01

    Full Text Available Com o objetivo de avaliar a influência da adição de Ni na solução nutritiva de Hoagland & Arnon sobre o crescimento e a nutrição mineral de mudas de umbuzeiro, realizou-se este trabalho. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições e seis doses de Ni (0; 0,0005; 0,05; 0,1; 0,5 e 1,0 mmol L-1. Observou-se que o Ni, em pequenas concentrações, estimula o crescimento de mudas de umbuzeiro em solução nutritiva; para o cultivo destas em solução nutritiva de Hoagland & Arnon, recomenda-se a adição de 0,03 mmol L-1 de Ni.This study evaluated the influence of Ni addition to Hoagland - Arnon nutrient solution on the growth and mineral nutrition of Umbu (Spondias tuberose tree seedlings. The experiment was in a completely randomized design with four replications and six Ni doses (0; 0.0005; 0.05; 0.1; 0.5; and 1.0 mmol L-1. Low Ni concentrations in the nutrient solution stimulated Umbu seedlings growth. The application of 0.03 mmol L-1 of Ni is recommended for the cultivation of Umbu seedlings in Hoagland - Arnon nutrient solution.

  7. Experimental and Numerical Study of Water Entry Supercavity Influenced by Turbulent Drag-Reducing Additives

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    Chen-Xing Jiang

    2014-04-01

    Full Text Available The configurational and dynamic characteristics of water entry supercavities influenced by turbulent drag-reducing additives were studied through supercavitating projectile approach, experimentally and numerically. The projectile was projected vertically into water and aqueous solution of CTAC with weight concentrations of 100, 500, and 1000 ppm, respectively, using a pneumatic nail gun. The trajectories of the projectile and the supercavity configuration were recorded by a high-speed CCD camera. Besides, water entry supercavities in water and CTAC solution were numerically simulated based on unsteady RANS scheme, together with application of VOF multiphase model. The Cross viscosity model was adopted to represent the fluid property of CTAC solution. It was obtained that the numerical simulation results are in consistence with experimental data. Numerical and experimental results all show that the length and diameter of supercavity in drag-reducing solution are larger than those in water, and the drag coefficient is smaller than that in water; the maintaining time of supercavity is longer in solution as well. The surface tension plays an important role in maintaining the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitation and drag reduction.

  8. Impact of decade-long warming, nutrient addition and shading on emission and carbon isotopic composition of CO2 from two subarctic dwarf shrub heaths

    DEFF Research Database (Denmark)

    Ravn, Nynne R.; Ambus, Per Lennart; Michelsen, Anders

    2017-01-01

    This study investigated ecosystem respiration, soil respiration and carbon isotopic composition in CO2 emitted from two subarctic shrub heaths with contrasting moisture regimes. The reported measurements were conducted 22 years (mesic heath) and 12 years (wet heath) upon initiation of in situ...... and soil respiration was measured using closed chambers and CO2 in the soil profile was sampled with gas probes installed at different depths. At the mesic heath ecosystem respiration was increased 46% by warming while soil respiration increased 133% by nutrient addition. At the wet heath, warming...... climate change related manipulations of temperature, nutrient availability and light. The aim was to quantify expected climatic change effects on soil and ecosystem respiration, and to investigate whether the emitted CO2 originates from old carbon stores in the soil or from newly fixed carbon. Ecosystem...

  9. Changes in soil carbon and nutrients following 6 years of litter removal and addition in a tropical semi-evergreen rain forest

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    E. V. J. Tanner

    2016-11-01

    Full Text Available Increasing atmospheric CO2 and temperature may increase forest productivity, including litterfall, but the consequences for soil organic matter remain poorly understood. To address this, we measured soil carbon and nutrient concentrations at nine depths to 2 m after 6 years of continuous litter removal and litter addition in a semi-evergreen rain forest in Panama. Soils in litter addition plots, compared to litter removal plots, had higher pH and contained greater concentrations of KCl-extractable nitrate (both to 30 cm; Mehlich-III extractable phosphorus and total carbon (both to 20 cm; total nitrogen (to 15 cm; Mehlich-III calcium (to 10 cm; and Mehlich-III magnesium and lower bulk density (both to 5 cm. In contrast, litter manipulation did not affect ammonium, manganese, potassium or zinc, and soils deeper than 30 cm did not differ for any nutrient. Comparison with previous analyses in the experiment indicates that the effect of litter manipulation on nutrient concentrations and the depth to which the effects are significant are increasing with time. To allow for changes in bulk density in calculation of changes in carbon stocks, we standardized total carbon and nitrogen on the basis of a constant mineral mass. For 200 kg m−2 of mineral soil (approximately the upper 20 cm of the profile about 0.5 kg C m−2 was “missing” from the litter removal plots, with a similar amount accumulated in the litter addition plots. There was an additional 0.4 kg C m−2 extra in the litter standing crop of the litter addition plots compared to the control. This increase in carbon in surface soil and the litter standing crop can be interpreted as a potential partial mitigation of the effects of increasing CO2 concentrations in the atmosphere.

  10. Experimental Study of Hydrogen Addition Effects on a Swirl-Stabilized Methane-Air Flame

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    Mao Li

    2017-11-01

    Full Text Available The effects of H2 addition on a premixed methane-air flame was studied experimentally with a swirl-stabilized gas turbine model combustor. Experiments with 0%, 25%, and 50% H2 molar fraction in the fuel mixture were conducted under atmospheric pressure. The primary objectives are to study the impacts of H2 addition on flame lean blowout (LBO limits, flame shapes and anchored locations, flow field characteristics, precessing vortex core (PVC instability, as well as the CO emission performance. The flame LBO limits were identified by gradually reducing the equivalence ratio until the condition where the flame physically disappeared. The time-averaged CH chemiluminescence was used to reveal the characteristics of flame stabilization, e.g., flame structure and stabilized locations. In addition, the inverse Abel transform was applied to the time-averaged CH results so that the distribution of CH signal on the symmetric plane of the flame was obtained. The particle image velocimetry (PIV was used to detect the characteristics of the flow field with a frequency of 2 kHz. The snapshot method of POD (proper orthogonal decomposition and fast Fourier transform (FFT were adopted to capture the most prominent coherent structures in the turbulent flow field. CO emission was monitored with an exhaust probe that was installed close to the combustor exit. The experimental results indicated that the H2 addition extended the flame LBO limits and the operation range of low CO emission. The influence of H2 addition on the flame shape, location, and flow field was observed. With the assistance of POD and FFT, the combustion suppression impacts on PVC was found.

  11. Co-digestion of manure with grass silage and pulp and paper mill sludge using nutrient additions.

    Science.gov (United States)

    Hagelqvist, Alina; Granström, Karin

    2016-08-01

    There is an increasing worldwide demand for biogas. Anaerobic co-digestion involves the treatment of different substrates with the aim of improving the production of biogas and the stability of the process. This study evaluates how methane production is affected by the co-digestion of pig and dairy manure with grass silage and pulp and paper mill sludge and assesses whether methane production is affected by factors other than nutrient deficiency, low buffering capacity, inadequate dilution, and an insufficient activity and amount of microorganism culture. Anaerobic digestion was performed in batch reactors under mesophilic conditions for 20 days. The season of grass silage and manure collection proved to be an important factor affecting methane production. Spring grass silage produced a maximum of 250 mL/VSadded and spring manure 150 mL/VSadded, whereas autumn grass silage produced at most 140 ml/VSadded and autumn manure 45 mL/VSadded. The pulp mill sludge used is comprised of both primary and secondary sludge and produced at most 50 mL/VSadded regardless of season; this substrate benefitted most from co-digestion.

  12. HYDROGEN ADDITION ON COMBUSTION AND EMISSION CHARACTERISTICS OF HIGH SPEED SPARK IGNITION ENGINE- AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    SHIVAPRASAD K. V.

    2016-11-01

    Full Text Available The present article aims at characterizing the combustion and emission parameters of a single cylinder high speed SI engine operating with different concentrations of hydrogen with gasoline fuel. The conventional carburetted SI engine was modified into an electronically controllable engine, wherein ECU was used to control the injection timings and durations of gasoline. The engine was maintained at a constant speed of 3000 rpm and wide open throttle position. The experimental results demonstrated that heat release rate and cylinder pressure were increased with the addition of hydrogen until 20%. The CO and HC emissions were reduced considerably whereas NOx emission was increased with the addition of hydrogen in comparison with pure gasoline engine operation.

  13. Epidermal growth factor and human growth hormone accelerate adaptation after massive enterectomy in an additive, nutrient-dependent, and site-specific fashion.

    Science.gov (United States)

    Iannoli, P; Miller, J H; Ryan, C K; Gu, L H; Ziegler, T R; Sax, H C

    1997-10-01

    After massive enterectomy (ME), remnant intestine undergoes compensatory adaptation. Epidermal growth factor (EGF) and human growth hormone (hGH) have each been shown to enhance total length small intestine nutrient transport after ME. This study aims to determine the differential effects of EGF and hGH on proximal and distal small intestinal remnants after ME. New Zealand white rabbits underwent 70% mid-jejunoileal resection. After 1 week, animals received hGH (0.2 mg/kg/day), EGF (1.5 micrograms/kg/hr), hGH + EGF, or vehicle (equal volume) for 7 days. Sodium-dependent uptake of glucose, glutamine, alanine, leucine, and arginine into brush border membrane vesicles was quantitated. Serum insulin-like growth factor-I concentrations as well as proximal and distal villus and microvillus heights were measured. IGF binding protein-3 and -4 mRNA expression was determined in full-thickness proximal and distal gut remnants. Concomitant hGH and EGF treatment up-regulates glucose (100%), glutamine (80%), and leucine (60%) transport in the proximal remnant; alanine (150%) and arginine (400%) transport in the distal remnant; and microvillus height (25% to 35%) both proximally and distally. Serum IGF-I levels and gross villus heights were not different among groups. Co-infusion of hGH and EGF accelerates intestinal adaptation after ME in an additive, nutrient-dependent, and site-specific fashion via enhanced nutrient transport as well as microvillus hypertrophy.

  14. Nutrient addition shifts plant community composition towards earlier flowering species in some prairie ecoregions in the U.S. Central Plains.

    Directory of Open Access Journals (Sweden)

    Lori Biederman

    Full Text Available The distribution of flowering across the growing season is governed by each species' evolutionary history and climatic variability. However, global change factors, such as eutrophication and invasion, can alter plant community composition and thus change the distribution of flowering across the growing season. We examined three ecoregions (tall-, mixed, and short-grass prairie across the U.S. Central Plains to determine how nutrient (nitrogen (N, phosphorus, and potassium (+micronutrient addition alters the temporal patterns of plant flowering traits. We calculated total community flowering potential (FP by distributing peak-season plant cover values across the growing season, allocating each species' cover to only those months in which it typically flowers. We also generated separate FP profiles for exotic and native species and functional group. We compared the ability of the added nutrients to shift the distribution of these FP profiles (total and sub-groups across the growing season. In all ecoregions, N increased the relative cover of both exotic species and C3 graminoids that flower in May through August. The cover of C4 graminoids decreased with added N, but the response varied by ecoregion and month. However, these functional changes only aggregated to shift the entire community's FP profile in the tall-grass prairie, where the relative cover of plants expected to flower in May and June increased and those that flower in September and October decreased with added N. The relatively low native cover in May and June may leave this ecoregion vulnerable to disturbance-induced invasion by exotic species that occupy this temporal niche. There was no change in the FP profile of the mixed and short-grass prairies with N addition as increased abundance of exotic species and C3 graminoids replaced other species that flower at the same time. In these communities a disturbance other than nutrient addition may be required to disrupt phenological

  15. Experimental analysis of an effect of the nutrient type and its concentration on the rheological properties of the baker’s yeast suspensions

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    Major-Godlewska Marta

    2015-09-01

    Full Text Available The aim of the study presented was to experimentally analyze an effect of the nutrient type and its concentration on the variability of rheological properties of the baker’s yeast suspensions for different time periods. Aqueous suspensions of the baker’s yeast of various concentration (solution I, without nutrient and yeasts suspended in aqueous solution of sucrose or honey as nutrients with different concentration (solution II or solution III were tested. Experiments were carried out using rotational rheoviscometer of type RT10 by a company HAAKE. The measurements were conducted for different time periods (from 1 h up to 144 h at given fluid temperature. On the basis of the obtained data, rheological characteristics of the aqueous solution of baker’s yeast suspensions without and with nutrients of different sucrose or honey concentration were identified and mathematically described.

  16. Altered leaf functional traits by nitrogen addition in a nutrient-poor pine plantation: A consequence of decreased phosphorus availability

    OpenAIRE

    Zheng, Lin-Lin; Zhao, Qiong; Yu, Zhan-Yuan; Zhao, Shan-Yu; Zeng, De-Hui

    2017-01-01

    This study aimed to determine how specific leaf area (SLA) and leaf dry matter content (LDMC) respond to N addition and understory vegetation removal in a 13-year-old Mongolian pine (Pinus sylvestris var. mongolica) plantation. Traits (SLA, LDMC, individual needle dry weight, N and P concentrations) of different-aged needles and their crown-average values were measured, and their relationships with soil N and P availability were examined. N addition and understory removal reduced soil Olsen-P...

  17. Parent's responses to nutrient claims and sports celebrity endorsements on energy-dense and nutrient-poor foods: an experimental study.

    Science.gov (United States)

    Dixon, Helen; Scully, Maree; Wakefield, Melanie; Kelly, Bridget; Chapman, Kathy; Donovan, Robert

    2011-06-01

    To assess parents' responses to common, potentially misleading strategies for marketing energy-dense and nutrient-poor (EDNP) child-oriented foods. Between-subjects online experiment to test whether nutrient claims and sports celebrity endorsements on the front of packs of EDNP products lead parents to prefer and rate these foods more favourably. Australia. A total of 1551 parents of children aged 5-12 years, who were the main household grocery buyers. Inclusion of nutrient claims or sports celebrity endorsements on EDNP products led parents to perceive these products to be more nutritious than if they did not include such promotions. When asked to choose between a pair of different products (EDNP v. healthier), 56 % of parents did not read a nutrition information panel (NIP) before making their choice and this did not differ by promotion condition. These parents were more likely to choose an EDNP product if it included a nutrient claim (OR = 1.83, 95 % CI 1.31, 2.56; P sports celebrity endorsement (OR = 2.37, 95 % CI 1.70, 3.32; P Sports celebrity endorsements also enhanced parent's perceptions of typical consumers of the product, perceptions of product healthiness and quality, as well as purchase intentions. Nutrient claims and sports celebrity endorsements tip consumer preferences towards EDNP products bearing such promotions, especially among the majority who do not read the NIP. As parents largely determine what foods are available to children at home, it is critical that initiatives aimed at reducing the persuasive impact of food marketing include this target group.

  18. Carbon-based stock feed additives: a research methodology that explores ecologically delivered C biosequestration, alongside live weights, feed use efficiency, soil nutrient retention, and perennial fodder plantations.

    Science.gov (United States)

    McHenry, Mark P

    2010-01-30

    There is considerable interest in reliable and practical methods to sequester carbon (C) into agricultural soils to both reduce atmospheric greenhouse gas concentrations and improve conventional productivity. This article outlines a research methodology to refine the efficacy and economics of using long-lived C species (biochars) as stock feed additives, produced from farm waste biomass, for ecologically delivered soil biosequestration, while generating renewable bioenergy. This article also draws attention to potential parallel outputs including annual feed use efficiency, fodder species expansion, soil nutrient retention, aquatic habitat protection, and forestry revegetation, using nitrogen-fixing perennial fodder plant species. A methodology to generate parallel results including standing fodder tree C sequestration, optimised production of Acacia spp. biochar, animal growth on high-tannin fodder with biochar feed additives, soil nutrient and stable C fractions, and economics of Acacia spp. bioenergy production. This form of research is contextually dependent on the regional agricultural production system, legislation, and surrounding ecosystem. Therefore, this article suggests the use of a scenario approach to include regionally specific levels of biochar integration with respect to the local prices for C, fossil fuels, meat and livestock, fertilisers, fodder, feed additives, water, renewable energy, revegetation and capital. (c) 2009 Society of Chemical Industry.

  19. Altered leaf functional traits by nitrogen addition in a nutrient-poor pine plantation: A consequence of decreased phosphorus availability.

    Science.gov (United States)

    Zheng, Lin-Lin; Zhao, Qiong; Yu, Zhan-Yuan; Zhao, Shan-Yu; Zeng, De-Hui

    2017-08-07

    This study aimed to determine how specific leaf area (SLA) and leaf dry matter content (LDMC) respond to N addition and understory vegetation removal in a 13-year-old Mongolian pine (Pinus sylvestris var. mongolica) plantation. Traits (SLA, LDMC, individual needle dry weight, N and P concentrations) of different-aged needles and their crown-average values were measured, and their relationships with soil N and P availability were examined. N addition and understory removal reduced soil Olsen-P by 15-91%. At the crown level, N addition significantly reduced foliar P concentration (by 19%) and SLA (by 8%), and elevated N concentration (by 31%), LDMC (by 10%) and individual leaf dry weight (by 14%); understory removal did not have a significant effect on all leaf traits. At the needle age level, traits of the previous year's needles responded more strongly to N addition and understory removal than the traits of current-year needles, particularly SLA and N concentration. SLA and LDMC correlated more closely with soil Olsen-P than with soil inorganic N, and LDMC correlated more closely with soil Olsen-P than SLA did. These results indicate that aggravated P limitation resulting from N addition and understory removal could constrain Mongolian pine growth through their effects on the leaf traits.

  20. The Effects of Additives in Napier Grass Silages on Chemical Composition, Feed Intake, Nutrient Digestibility and Rumen Fermentation

    Directory of Open Access Journals (Sweden)

    Smerjai Bureenok

    2012-09-01

    Full Text Available The effect of silage additives on ensiling characteristics and nutritive value of Napier grass (Pennisetum purpureum silages was studied. Napier grass silages were made with no additive, fermented juice of epiphytic lactic acid bacteria (FJLB, molasses or cassava meal. The ensiling characteristics were determined by ensiling Napier grass silages in airtight plastic pouches for 2, 4, 7, 14, 21 and 45 d. The effect of Napier grass silages treated with these additives on voluntary feed intake, digestibility, rumen fermentation and microbial rumen fermentation was determined in 4 fistulated cows using 4×4 Latin square design. The pH value of the treated silages rapidly decreased, and reached to the lowest value within 7 d of the start of fermentation, as compared to the control. Lactic acid content of silages treated with FJLB was stable at 14 d of fermentation and constant until 45 d of ensiling. At 45 d of ensiling, neutral detergent fiber (NDF and acid detergent fiber (ADF of silage treated with cassava meal were significantly lower (p<0.05 than the others. In the feeding trial, the intake of silage increased (p<0.05 in the cow fed with the treated silage. Among the treatments, dry matter intake was the lowest in the silage treated with cassava meal. The organic matter, crude protein and NDF digestibility of the silage treated with molasses was higher than the silage without additive and the silage treated with FJLB. The rumen parameters: ruminal pH, ammonia-nitrogen (NH3-N, volatile fatty acid (VFA, blood urea nitrogen (BUN and bacterial populations were not significantly different among the treatments. In conclusion, these studies confirmed that the applying of molasses improved fermentative quality, feed intake and digestibility of Napier grass.

  1. Aquatic toxicity assessment of the additive 6-methylcoumarine using four experimental systems.

    Science.gov (United States)

    Jos, A; Repetto, G; Ríos, J C; Del Peso, A; Salguero, M; Cameán, A M

    2009-01-01

    The toxicity assessment of chemicals is one of the main issues in the current policies in order to protect the health of the environment and human beings. Food and cosmetic additives have been extensively studied in relation to their toxicity to humans, but data about their ecotoxicological effects are scarce. The aim of this study was to evaluate the toxic effects of the additive 6-methylcoumarine in the aquatic milieu using a test battery comprising experimental model systems from different trophic levels. The inhibition of bioluminiscence was studied in the bacteria Vibrio fischeri (decomposer), the inhibition of growth was evaluated in the alga Chlorella vulgaris (producer) and immobilization was studied in the cladoceran Daphnia magna (first consumer). Finally, several end points were evaluated in the RTG-2 salmonid fish cell line, including neutral red uptake, protein content, methylthiazol tetrazolium salt metabolization, glucose-6-phosphate dehydrogenase activity, lactate dehydrogenase activity and leakage, and morphology. The sensitivity of the test systems employed was as follows: V. fischeri > D. magna > C. vulgaris > RTG-2 cell line. The results show that 6-methylcoumarine is not expected to produce acute toxic effects on the aquatic biota. However, chronic and synergistic effects with other chemicals cannot be excluded and should be further investigated.

  2. An Experimental Study on Effect of Palm – Shell Waste Additive to Cement Strenght Enhancement

    Directory of Open Access Journals (Sweden)

    Adi Novriansyah

    2017-03-01

    Full Text Available Enhancing the cement strength through attaching chemical additive has been popular to meet the required condition for a particular well-cementing job. However, due to a low oil-price phenomenon, pouring and additive should be reconsidered because it can raise the cost and make the project become uneconomic. Another additive material in nanocomposite form will be introduced through this experimental study. The nanocomposite material consist of silica nanoparticle, known as “Nanosilica” and a palm-shell-waste, which is abundant in Indonesia. Before making a nanocomposite, the palm-shell should be burned to obtain a charcoal form, ground and sieved to attain a uniform size.   The study focuses on the two parameters, compressive strength and shear bond strength, which can reflect the strength of the cement. These values are obtained by performing a biaxial loading test to the cement sample. Various samples with different concentration of nanocomposite should be prepared and following the mixing, drying, and hardening process before the loading test is carried out. The result from the test shows a positive indication for compressive strength and shear bond strength values, according to the representative well cementing standards. Increasing the nanocomposite concentration on the cement will increase these values. Furthermore, an investigation on the temperature effect confirms that the sample with 700oC burning temperature have highest compressive-strength and shear-bond-strength values. This is a potential opportunity utilizing a waste-based material to produce another product with higher economic value.

  3. Hydrothermally treated chitosan hydrogel loaded with copper and zinc particles as a potential micro-nutrient based antimicrobial feed additive

    Directory of Open Access Journals (Sweden)

    Parthiban eRajasekaran

    2015-11-01

    Full Text Available Large-scale use of antibiotics in food animal farms as growth promoters is considered as one of the driving factors behind increasing incidence of microbial resistance. Several alternatives are under investigation to reduce the amount of total antibiotics used in order to avoid any potential transmission of drug resistant microbes to humans through food chain. Copper sulfate and zinc oxide salts are used as feed supplement as they exhibit antimicrobial properties in addition to being micronutrients. However, higher dosage of copper and zinc (often needed for growth promoting effect to animals is not advisable because of potential environmental toxicity arising from excreta. Innovative strategies are needed to utilize the complete potential of trace minerals as growth promoting feed supplements. To this end, we describe here the development and preliminary characterization of hydrothermally treated chitosan as a delivery vehicle for copper and zinc nanoparticles that could act as a micronutrient based antimicrobial feed supplement. Material characterization studies showed that hydrothermal treatment makes a chitosan hydrogel that re-arranged to capture the copper and zinc metal particles. Systemic antimicrobial assays showed that this chitosan biopolymer matrix embedded with copper (57.6 μg/ml and zinc (800 μg/ml reduced the load of model gut-bacteria (target organisms of growth promoting antibiotics such as Escherichia coli, Enterococcus faecalis, Staphylococcus aureus and Lactobacillus fermentum under in vitro conditions. Particularly, the chitosan/copper/zinc hydrogel exhibited significantly higher antimicrobial effect against L. fermentum, one of the primary targets of antibiotic growth promoters. Additionally, the chitosan matrix ameliorated the cytotoxicity levels of metal supplements when screened against a murine macrophage cell line RAW 264.7 and in TE-71, a murine thymic epithelial cell line. In this proof of concept study, we show

  4. Effects of water addition to total mixed ration on water intake, nutrient digestibility, wool cortisol and blood indices in Corriedale ewes.

    Science.gov (United States)

    Nejad, Jalil Ghassemi; Kim, Byong-Wan; Lee, Bae-Hun; Kim, Ji-Yung; Sung, Kyung-Il

    2017-10-01

    The objective of this study was to determine the effect of adding water to total mixed ration (TMR) on fresh water intake, nutrient digestibility, wool cortisol, and blood indices in Corriedale ewes under hot and humid conditions. Nine non-pregnant Corriedale ewes (ave. body weight = 41±3.5 kg) were individually fed diets based on maintenance requirements in metabolic crates. Ewes were assigned to three treatment groups according to a triplicate 3×3 Latin Square design for 3 periods of 21 days duration each (9 ewes per treatment, 27 replications). Treatments were TMR (crude protein [CP] = 16.1, total digestible nutrients = 69.1%) moisture levels for 40%, 50%, and 60%. No differences were found in body weight gain among all treatment groups (p>0.05). Nitrogen balance including digestible N, retained N, and urinary and fecal N showed no change among the treatment groups (p>0.05). Fresh water intake was the lower in 50% TMR moisture group than in the other groups (p0.05). No significant difference was observed for serum protein, blood urea nitrogen, glucose, and triglyceride among the treatment groups (p>0.05). Wool and blood cortisol were not different among the treatment groups (p>0.05). Blood hematology including red blood cell, white blood cells, hemoglobin, hematocrit, basophils, and eosinophils were not different among the treatment groups (p>0.05). It is concluded that TMR moisture at 40%, 50%, and 60% had no effects on N balance parameters, and nutrient digestibilities except for the ether extract under hot and humid conditions. Additionally there were no effects on stress conditions include wool cortisol, as well as blood cortisol levels of ewes.

  5. Effects of water addition to total mixed ration on water intake, nutrient digestibility, wool cortisol and blood indices in Corriedale ewes

    Directory of Open Access Journals (Sweden)

    Jalil Ghassemi Nejad

    2017-10-01

    Full Text Available Objective The objective of this study was to determine the effect of adding water to total mixed ration (TMR on fresh water intake, nutrient digestibility, wool cortisol, and blood indices in Corriedale ewes under hot and humid conditions. Methods Nine non-pregnant Corriedale ewes (ave. body weight = 41±3.5 kg were individually fed diets based on maintenance requirements in metabolic crates. Ewes were assigned to three treatment groups according to a triplicate 3×3 Latin Square design for 3 periods of 21 days duration each (9 ewes per treatment, 27 replications. Treatments were TMR (crude protein [CP] = 16.1, total digestible nutrients = 69.1% moisture levels for 40%, 50%, and 60%. Results No differences were found in body weight gain among all treatment groups (p>0.05. Nitrogen balance including digestible N, retained N, and urinary and fecal N showed no change among the treatment groups (p>0.05. Fresh water intake was the lower in 50% TMR moisture group than in the other groups (p0.05. No significant difference was observed for serum protein, blood urea nitrogen, glucose, and triglyceride among the treatment groups (p>0.05. Wool and blood cortisol were not different among the treatment groups (p>0.05. Blood hematology including red blood cell, white blood cells, hemoglobin, hematocrit, basophils, and eosinophils were not different among the treatment groups (p>0.05. Conclusion It is concluded that TMR moisture at 40%, 50%, and 60% had no effects on N balance parameters, and nutrient digestibilities except for the ether extract under hot and humid conditions. Additionally there were no effects on stress conditions include wool cortisol, as well as blood cortisol levels of ewes.

  6. Infiltration of natural caries lesions with experimental resins differing in penetration coefficients and ethanol addition.

    Science.gov (United States)

    Meyer-Lueckel, H; Paris, Sebastian

    2010-01-01

    Resin infiltration of enamel caries lesions requires materials optimized for penetration into the capillary structures of the lesion body. With increasing penetration coefficients (PC) improved penetration and caries-inhibiting properties of low-viscosity resins (infiltrants) could be observed in artificial caries lesions. The aim of the present in vitro study was to compare the penetrativity of experimental resins varying in PC and ethanol addition into natural caries lesions using this technique. Extracted human molars and premolars showing proximal white spot lesions (International Caries Detection and Assessment System: code 2) were etched for 2 min using 15% hydrochloric acid gel. After drying, the lesions were stained with tetramethylrhodamine isothiocyanate and 1 of 4 experimental resins (PC63; PC185; PC204; PC391) was applied for 5 min. The materials consisted of bisphenol-A-glycidyl-methacrylate (B), tri-ethylene-glycol-dimethacrylate (T) and ethanol (E) in ratios (B:T:E) of PC63: 25:75:0; PC185: 20:60:20; PC204: 0:100:0; PC391: 0:80:20. Excess material was removed before light curing. The teeth were sectioned perpendicularly to the lesion surfaces and unbound dye was bleached by immersion in hydrogen peroxide. The remaining lesion pores were stained with fluorescein solution. Lesion and penetration depths were analyzed using confocal microscopy (n = 60). At deep lesion sites the percentage penetration of PC204 was significantly higher compared to PC63 and PC391 (p 0.05). It can be concluded that materials with high PC (infiltrants) are capable of penetrating almost completely into enamel parts of natural caries lesions in vitro. A solvent-free resin mainly consisting of triethylene glycol dimethacrylate seems to be preferable. Copyright 2010 S. Karger AG, Basel.

  7. Sustainable nutrients recovery and recycling by optimizing the chemical addition sequence for struvite precipitation from raw swine slurries.

    Science.gov (United States)

    Taddeo, Raffaele; Kolppo, Kari; Lepistö, Raghida

    2016-09-15

    Livestock farming contributes heavily to nitrogen (N) and phosphorus (P) flows into the environment, a major cause of eutrophication of coastal and freshwater systems. Furthermore, the growing demand for N-P fertilizers is increasing the emission of anthropogenic reactive N into the atmosphere and the depletion of the current P reserves. Therefore, it is essential to minimize the anthropogenic impact on the environment and recycle the wasted N-P for agricultural reuse. This study focused on enhancing struvite (MgNH4PO4*6H2O) precipitation from raw swine slurries in batch and laboratory-scale reactors. Different chemical addition sequences were evaluated, and the best removal efficiency (E%) was obtained when the chemicals were mixed before the precipitation process. Struvite was detected at a pH as low as 6 (E%N-P∼50%), and high E%N-P was found at pH 7-9.5 (80-95%). Furthermore, air stripping was used in place of NaOH to adjust pH, returning the same efficiency as if only alkali had been used. XRD and FE-SEM analysis of the precipitate showed that the recovered struvite was of high purity with orthorhombic crystalline structure and only trace amounts of impurities from matrix organics, co-precipitation products (CaO and amorphous calcium-phosphates), and residuals of added chemicals (MgO). Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The ecological stoichiometry of toxins produced by harmful cyanobacteria: an experimental test of the carbon-nutrient balance hypothesis

    NARCIS (Netherlands)

    Van de Waal, D.B.; Verspagen, J.M.H.; Lürling, M.; Van Donk, E.; Visser, P.M.; Huisman, J.

    2009-01-01

    The elemental composition of primary producers reflects the availability of light, carbon and nutrients in their environment. According to the carbon-nutrient balance hypothesis, this has implications for the production of secondary metabolites. To test this hypothesis, we investigated a family of

  9. The ecological stoichiometry of toxins produced by harmful cyanobacteria: An experimental test of the carbon-nutrient balance hypothesis

    NARCIS (Netherlands)

    van de Waal, D.B.; Verspagen, J.M.H.; Lürling, M.; van Donk, E.; Visser, P.M.; Huisman, J.

    2009-01-01

    The elemental composition of primary producers reflects the availability of light, carbon and nutrients in their environment. According to the carbon-nutrient balance hypothesis, this has implications for the production of secondary metabolites. To test this hypothesis, we investigated a family of

  10. Additive effect of rPb27 immunization and chemotherapy in experimental paracoccidioidomycosis.

    Directory of Open Access Journals (Sweden)

    Viviane C Fernandes

    Full Text Available Paracoccidioidomycosis, PCM, the major systemic mycosis in Latin America, is caused by the termally dimorphic fungus Paracoccidioides brasiliensis and requires extended periods of chemotherapy with a significant frequency of relapsing disease. The search for new alternatives of treatment is necessary. rPb27 is an antigenic protein from P. brasiliensis that already showed a significant protective activity as a vaccine for PCM in experimental models. The cDNA of rPb27 was subcloned into a pET-DEST 42 plasmid, expressed in E. coli with a his-tag and purified by affinity chromatography. Immunization with this recombinant protein and chemotherapy were used together in an attempt to improve treatment of PCM. For this, BALB/c mice were challenged with pathogenic P. brasiliensis strain and after immunized with rPb27, in the presence of Corynebacterium parvum and Al(OH(3, some groups were also treated with fluconazole. After 40 days of treatment, the combined drug/rPb27 administration controlled PCM in the liver and spleen, with long lasting protection, and largely preserved tissues structures of these organs. Additionally, in the lungs after 40 days of treatment there was a significant reduction in the fungal load and size of lesions. At the same time, the levels of TNF-α were higher than infected-only mice. Moreover, significant levels of anti-rPb27 specific IgG1, IgG2a and IgG2b isotypes were detected in the sera of mice immunized with rPb27 fluconazole treated or not. These results showed an additive protective effect of rPb27 immunization and chemotherapy, suggesting that an rPb27-based vaccine can be used to enhance PCM antifungal treatment.

  11. Efecto del enriquecimiento con nutrientes en la degradación de clorpirifos, malatión y metil paratión Inorganic nutrients effect addition over the chlorpyrifos, malathion and methyl parathion degradation

    Directory of Open Access Journals (Sweden)

    S. A. Upegui

    2011-01-01

    Full Text Available Con el fin de evaluar el efecto del enriquecimiento con nutrientes (una sal de fósforo o un fertilizante comercial con N, P y K como alternativa para mejorar la capacidad de degradación de los microorganismos en una matriz sólida, contaminada con los pesticidas organofosforados: clorpirifos, malatión y metil paratión, se realizaron experimentos de cultivo bajo condiciones controladas de oscuridad, temperatura y humedad por 30 días. En todos los tratamientos hubo degradación de los pesticidas; sin embargo, en el tratamiento con fósforo los tiempos para degradar el clorpirifos y el metil paratión fueron mayores. La presencia de los pesticidas no generó efectos tóxicos detectables sobre la microflora en ninguno de los tratamientos evaluados. La actividad biológica de las matrices no presentó una relación directa con la capacidad de degradación.In order to evaluate the effect of inorganic nutrient addition (phosphorus or commercial fertilizer over the microbial degradation capacity present in a solid matrix contaminated with chlorpyrifos, malathion and methyl parathion, microcosms assays were held under controlled conditions of light, moisture and temperature for 30 days. Results showed that even though three treatments microorganisms were able to degrade the three organophosphorus pesticides, microorganisms of phosphorus-enrichment treatment were less efficient to degrade Chlorpyrifos and Methyl Parathion than microorganisms of Fertilizer-enrichment treatment. It was not observed a direct relation between mineralization and microbial pesticides degradation capacity. The microbial activity was not affected by the presence of organophosphorus pesticides.

  12. Time-Resolved In Situ Measurements During Rapid Alloy Solidification: Experimental Insight for Additive Manufacturing

    Science.gov (United States)

    McKeown, Joseph T.; Zweiacker, Kai; Liu, Can; Coughlin, Daniel R.; Clarke, Amy J.; Baldwin, J. Kevin; Gibbs, John W.; Roehling, John D.; Imhoff, Seth D.; Gibbs, Paul J.; Tourret, Damien; Wiezorek, Jörg M. K.; Campbell, Geoffrey H.

    2016-03-01

    Additive manufacturing (AM) of metals and alloys is becoming a pervasive technology in both research and industrial environments, though significant challenges remain before widespread implementation of AM can be realized. In situ investigations of rapid alloy solidification with high spatial and temporal resolutions can provide unique experimental insight into microstructure evolution and kinetics that are relevant for AM processing. Hypoeutectic thin-film Al-Cu and Al-Si alloys were investigated using dynamic transmission electron microscopy to monitor pulsed-laser-induced rapid solidification across microsecond timescales. Solid-liquid interface velocities measured from time-resolved images revealed accelerating solidification fronts in both alloys. The observed microstructure evolution, solidification product, and presence of a morphological instability at the solid-liquid interface in the Al-4 at.%Cu alloy are related to the measured interface velocities and small differences in composition that affect the thermophysical properties of the alloys. These time-resolved in situ measurements can inform and validate predictive modeling efforts for AM.

  13. Additive-manufactured sandwich lattice structures: A numerical and experimental investigation

    Science.gov (United States)

    Fergani, Omar; Tronvoll, Sigmund; Brøtan, Vegard; Welo, Torgeir; Sørby, Knut

    2017-10-01

    The utilization of additive-manufactured lattice structures in engineered products is becoming more and more common as the competitiveness of AM as a production technology has increased during the past several years. Lattice structures may enable important weight reductions as well as open opportunities to build products with customized functional properties, thanks to the flexibility of AM for producing complex geometrical configurations. One of the most critical aspects related to taking AM into new application areas—such as safety critical products—is currently the limited understanding of the mechanical behavior of sandwich-based lattice structure mechanical under static and dynamic loading. In this study, we evaluate manufacturability of lattice structures and the impact of AM processing parameters on the structural behavior of this type of sandwich structures. For this purpose, we conducted static compression testing for a variety of geometry and manufacturing parameters. Further, the study discusses a numerical model capable of predicting the behavior of different lattice structure. A reasonably good correlation between the experimental and numerical results was observed.

  14. Modeling, Simulation, Additive Manufacturing, and Experimental Evaluation of Solid and Porous NiTi

    Science.gov (United States)

    Taheri Andani, Mohsen

    In recent years, shape memory alloys (SMAs) have entered a wide range of engineering applications in fields such as aerospace and medical applications. Nickel-titanium (NiTi) is the most commonly used SMAs due to its excellent functional characteristics (shape memory effect and superelasticity behavior). These properties are based on a solid-solid phase transformation between martensite and austenite. Beside these two characteristics, low stiffness, biocompatibility and corrosion properties of NiTi make it an attractive candidate for biomedical applications (e.g., bone plates, bone screws, and vascular stents). It is well know that manufacturing and processing of NiTi is very challenging. The functional properties of NiTi are significantly affected by the impurity level and due to the high titanium content, NiTi are highly reactive. Therefore, high temperature processed parts through methods such as melting and casting which result in increased impurity levels have inadequate structural and functional properties. Furthermore, high ductility and elasticity of NiTi, adhesion, work hardening and spring back effects make machining quite challenging. These unfavorable effects for machining cause significant tool wear along with decreasing the quality of work piece. Recently, additive manufacturing (AM) has gained significant attention for manufacturing NiTi. Since AM can create a part directly from CAD data, it is predicted that AM can overcome most of the manufacturing difficulties. This technique provides the possibility of fabricating highly complex parts, which cannot be processed by any other methods. Curved holes, designed porosity, and lattice like structures are some examples of mentioned complex parts. This work investigates manufacturing superelastic NiTi by selective laser melting (SLM) technique (using PXM by Phenix/3D Systems). An extended experimental study is conducted on the effect of subsequent heat treatments with different aging conditions on phase

  15. Experimental Study of Disruption of Columnar Grains During Rapid Solidification in Additive Manufacturing

    Science.gov (United States)

    Manogharan, Guha; Yelamanchi, Bharat; Aman, Ronald; Mahbooba, Zaynab

    2016-03-01

    Over the years, many studies have been conducted to study and analyze the grain structures of metal alloys during additive manufacturing to improve mechanical properties. In particular, columnar grains are observed predominantly during rapid solidification of molten metal. This leads to lower mechanical properties and requires expensive secondary heat-treatment processes. This study is aimed at disrupting the formation of columnar grain growth during rapid solidification using ultrasonic vibration and analyzes the effects on grain structure and mechanical properties. A gas-metal arc welder mounted on a Rep-Rap-based low-cost metal 3 Dimension printer was used to deposit ER70S-6 mild steel layers on a plate. A contact-type ultrasonic transducer with a control system to vary the frequency and power of the vibration was used. The effects of ultrasonic vibration were determined from the statistical analysis of microstructure and micro-indentation techniques on the deposited layer and heat-affected zone. It was found that both frequency and interaction between frequency and power had significant impact on the refinement of average grain size up to 10.64% and increased the number of grains by approximately 41.78%. Analysis of micro-indentation tests showed that there was an increase of approximately 14.30% in micro-hardness due to the applied frequency during rapid solidification. A pole diagram shows that application of vibration causes randomization of grain orientation. Along with the results from this study, further efforts in modeling and experimentation of multi-directional vibrations would lead to a better understanding of disrupting columnar grains in applications that use mechanical vibrations, such as welding, directed energy deposition, brazing, etc.

  16. The effects of nutrient additions on particulate and dissolved primary production and metabolic state in surface waters of three Mediterranean eddies

    Directory of Open Access Journals (Sweden)

    A. Lagaria

    2011-09-01

    Full Text Available We examined the effects of nutrient additions on rates of 14C-based particulate and dissolved primary production as well as O2-based metabolic rates in surface waters (8 m of three anticyclonic eddies, located in the Western, Central and Eastern Mediterranean. Ship-board microcosm experiments employing additions of inorganic nitrogen (+N and phosphorus (+P, alone and in combination (+NP, were conducted in June/July 2008 during the BOUM (Biogeochemistry from the Oligotrophic to the Ultra-oligotrophic Mediterranean cruise. In all three experiments, particulate primary production was significantly stimulated by the additions of nitrogen (+N, +NP while no effect was observed with the addition of phosphorus alone (+P. Percent extracellular release of photosynthate (PER displayed the lowest values (4–8 % in the +NP treatment. Among the three treatments (+N, +P, +NP, the +NP had the strongest effect on oxygen metabolic rates, leading to positive values of net community production (NCP > 0. These changes of NCP were mainly due to enhanced gross primary production (GPP rather than reduced dark community respiration rates (DCR. In all three sites, in +NP treatment autotrophic production (whether expressed as GPP or PPtotal was sufficient to fulfil the estimated carbon requirements of heterotrophic prokaryotes, while addition of nitrogen alone (+N had a weaker effect on GPP, resulting in metabolically balanced systems. At the three sites, in treatments with N (+N, +NP, phytoplankton and heterotrophic prokaryote production were positively correlated. Heterotrophic conditions were observed in the Control and +P treatment at the central and eastern sites, and autotrophic production was not sufficient to supply estimated bacterial carbon demand, evidence of a decoupling of phytoplankton production and consumption by heterotrophic prokaryotes.

  17. Experimental study of hydrogen as a fuel additive in internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Saanum, Inge

    2008-07-01

    Combustion of hydrocarbons in internal combustion engines results in emissions that can be harmful both to human health and to the environment. Although the engine technology is improving, the emissions of NO{sub x}, PM and UHC are still challenging. Besides, the overall consumption of fossil fuel and hence the emissions of CO{sub 2} are increasing because of the increasing number of vehicles. This has lead to a focus on finding alternative fuels and alternative technologies that may result in lower emissions of harmful gases and lower CO{sub 2} emissions. This thesis treats various topics that are relevant when using blends of fuels in different internal combustion engine technologies, with a particular focus on using hydrogen as a fuel additive. The topics addressed are especially the ones that impact the environment, such as emissions of harmful gases and thermal efficiency (fuel consumption). The thesis is based on experimental work performed at four different test rigs: 1. A dynamic combustion rig with optical access to the combustion chamber where spark ignited premixed combustion could be studied by means of a Schlieren optical setup and a high speed video camera. 2. A spark ignition natural gas engine rig with an optional exhaust gas recycling system. 3. A 1-cylinder diesel engine prepared for homogeneous charge compression ignition combustion. 4. A 6-cylinder standard diesel engine The engine rigs were equipped with cylinder pressure sensors, engine dynamometers, exhaust gas analyzers etc. to enable analyses of the effects of different fuels. The effect of hydrogen blended with methane and natural gas in spark ignited premixed combustion was investigated in the dynamic combustion rig and in a natural gas engine. In the dynamic combustion rig, the effect of hydrogen added to methane on the flame speed and the flame structure was investigated at elevated pressure and temperature. A considerable increase in the flame speed was observed when adding 30 vol

  18. Increase in the carbohydrate content of the microalgae Spirulina in culture by nutrient starvation and the addition of residues of whey protein concentrate.

    Science.gov (United States)

    Vieira Salla, Ana Cláudia; Margarites, Ana Cláudia; Seibel, Fábio Ivan; Holz, Luiz Carlos; Brião, Vandré Barbosa; Bertolin, Telma Elita; Colla, Luciane Maria; Costa, Jorge Alberto Vieira

    2016-06-01

    Non-renewable sources that will end with time are the largest part of world energy consumption, which emphasizes the necessity to develop renewable sources of energy. This necessity has created opportunities for the use of microalgae as a biofuel. The use of microalgae as a feedstock source for bioethanol production requires high yields of both biomass and carbohydrates. With mixotrophic cultures, wastewater can be used to culture algae. The aim of the study was to increase the carbohydrate content in the microalgae Spirulina with the additions of residues from the ultra and nanofiltration of whey protein. The nutrient deficit in the Zarrouk medium diluted to 20% and the addition of 2.5% of both residue types led to high carbohydrate productivity (60 mg L(-1) d(-1)). With these culture conditions, the increase in carbohydrate production in Spirulina indicated that the conditions were appropriate for use with microalgae as a feedstock in the production of bioethanol. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Effects of nutrient content claims, sports celebrity endorsements and premium offers on pre-adolescent children's food preferences: experimental research.

    Science.gov (United States)

    Dixon, H; Scully, M; Niven, P; Kelly, B; Chapman, K; Donovan, R; Martin, J; Baur, L A; Crawford, D; Wakefield, M

    2014-04-01

    To assess pre-adolescent children's responses to common child-oriented front-of-pack food promotions. Between-subjects, web-based experiment with four front-of-pack promotion conditions on energy-dense and nutrient-poor (EDNP) foods: no promotion [control]; nutrient content claims; sports celebrity endorsements (male athletes) and premium offers. Participants were 1302 grade 5 and 6 children (mean age 11 years) from Melbourne, Australia. Participants chose their preferred product from a randomly assigned EDNP food pack and comparable healthier food pack then completed detailed product ratings. Child-oriented pack designs with colourful, cartooned graphics, fonts and promotions were used. Compared to the control condition, children were more likely to choose EDNP products featuring nutrient content claims (both genders) and sports celebrity endorsements (boys only). Perceptions of nutritional content were enhanced by nutrient content claims. Effects of promotions on some product ratings (but not choice) were negated when children referred to the nutrition information panel. Premium offers did not enhance children's product ratings or choice. Nutrient content claims and sports celebrity endorsements influence pre-adolescent children's preferences towards EDNP food products displaying them. Policy interventions to reduce the impact of unhealthy food marketing to children should limit the use of these promotions. © 2013 The Authors. Pediatric Obesity © 2013 International Association for the Study of Obesity.

  20. Experimentally increased nutrient availability at the permafrost thaw front selectively enhances biomass production of deep-rooting subarctic peatland species.

    Science.gov (United States)

    Keuper, Frida; Dorrepaal, Ellen; van Bodegom, Peter M; van Logtestijn, Richard; Venhuizen, Gemma; van Hal, Jurgen; Aerts, Rien

    2017-10-01

    Climate warming increases nitrogen (N) mineralization in superficial soil layers (the dominant rooting zone) of subarctic peatlands. Thawing and subsequent mineralization of permafrost increases plant-available N around the thaw-front. Because plant production in these peatlands is N-limited, such changes may substantially affect net primary production and species composition. We aimed to identify the potential impact of increased N-availability due to permafrost thawing on subarctic peatland plant production and species performance, relative to the impact of increased N-availability in superficial organic layers. Therefore, we investigated whether plant roots are present at the thaw-front (45 cm depth) and whether N-uptake ((15) N-tracer) at the thaw-front occurs during maximum thaw-depth, coinciding with the end of the growing season. Moreover, we performed a unique 3-year belowground fertilization experiment with fully factorial combinations of deep- (thaw-front) and shallow-fertilization (10 cm depth) and controls. We found that certain species are present with roots at the thaw-front (Rubus chamaemorus) and have the capacity (R. chamaemorus, Eriophorum vaginatum) for N-uptake from the thaw-front between autumn and spring when aboveground tissue is largely senescent. In response to 3-year shallow-belowground fertilization (S) both shallow- (Empetrum hermaphroditum) and deep-rooting species increased aboveground biomass and N-content, but only deep-rooting species responded positively to enhanced nutrient supply at the thaw-front (D). Moreover, the effects of shallow-fertilization and thaw-front fertilization on aboveground biomass production of the deep-rooting species were similar in magnitude (S: 71%; D: 111% increase compared to control) and additive (S + D: 181% increase). Our results show that plant-available N released from thawing permafrost can form a thus far overlooked additional N-source for deep-rooting subarctic plant species and increase their

  1. Soil N2O fluxes along an elevation gradient of tropical montane forests under experimental nitrogen and phosphorus addition

    Directory of Open Access Journals (Sweden)

    Anke K. Müller

    2015-10-01

    Full Text Available Nutrient deposition to tropical forests is increasing, which could affect soil fluxes of nitrous oxide (N2O, a powerful greenhouse gas. We assessed the effects of 35-56 months of moderate nitrogen (N and phosphorus (P additions on soil N2O fluxes and net soil N-cycling rates, and quantified the relative contributions of nitrification and denitrification to N2O fluxes. In 2008, a nutrient manipulation experiment was established along an elevation gradient (1000, 2000 and 3000 m of montane forests in southern Ecuador. Treatments included control, N, P and N+P addition (with additions of 50 kg N ha−1 yr-1 and 10 kg P ha−1 yr-1. Nitrous oxide fluxes were measured using static, vented chambers and N cycling was determined using the buried bag method. Measurements showed that denitrification was the main N2O source at all elevations, but that annual N2O emissions from control plots were low, and decreased along the elevation gradient (0.57 ± 0.26 to 0.05 ± 0.04 kg N2O-N ha-1 yr-1. We attributed the low fluxes to our sites’ conservative soil N cycling as well as gaseous N losses possibly being dominated by N2. Contrary to the first 21 months of the experiment, N addition did not affect N2O fluxes during the 35-56 month period, possibly due to low soil moisture contents during this time. With P addition, N2O fluxes and mineral N concentrations decreased during Months 35-56, presumably because plant P limitations were alleviated, increasing plant N uptake. Nitrogen plus phosphorus addition showed similar trends to N addition, but less pronounced given the counteracting effects of P addition. The combined results from this study (Months 1-21 and 35-56 showed that effects of N and P addition on soil N2O fluxes were not linear with time of exposure, highlighting the importance of long-term studies.

  2. Residual Effect Of Organic Fertilizer And Addition Inorganik Fertilizer To Nutrient Uptake Growth And Productions Of Black Soy Bean Glycine Max L. Merr At Rainfed Areas.

    Directory of Open Access Journals (Sweden)

    Elli Afrida

    2015-02-01

    Full Text Available Abstract Research that have theme Residual Effect of Organic Fertilizer and Addition Anorganik Fertilizer to Nutrient Uptake Growth and pruductions of Black Soy Bean Glycine max L. Merr at Rainfed Wetland. Research was conducted at Suka Makmur village sub-distric Binjai Distric Langkat. Research was arranged in split plot design main plot is applications of phonska fertilizerwith 4 level i.e 0 t ha-1 A0 0.20 t ha-1 A1 0.25 t ha-1 A2 dan 0.30 t ha-1 A3 and sub plot is residual effect from first research with 16 combinations. Research was replicated 3 times. Result of research was showed application organic fertilizer that was combinated with anorganic fertilizer can increased N and K uptake. Application organic and anorganic fertilizer as single factor showed significantly effect of number of pods and soy bean productions but at interaction treatment not significantly effect however generally occurs increased production at O33A3 tratment until 80 comparison with control.

  3. Bioremediation of storage tank bottom sludge by using a two-stage composting system: Effect of mixing ratio and nutrients addition.

    Science.gov (United States)

    Koolivand, Ali; Rajaei, Mohammad Sadegh; Ghanadzadeh, Mohammad Javad; Saeedi, Reza; Abtahi, Hamid; Godini, Kazem

    2017-07-01

    The effect of mixing ratio and nutrients addition on the efficiency of a two-stage composting system in removal of total petroleum hydrocarbons (TPH) from storage tank bottom sludge (STBS) was investigated. The system consisted of ten windrow piles as primary composting (PC) followed by four in-vessel reactors as secondary composting (SC). Various initial C/N/P and mixing ratios of STBS to immature compost (IC) were examined in the PC and SC for 12 and 6weeks, respectively. The removal rates of TPH in the two-stage system (93.72-95.24%) were higher than those in the single-stage one. Depending on the experiments, TPH biodegradation fitted to the first- and second-order kinetics with the rate constants of 0.051-0.334d-1 and 0.002-0.165gkg-1d-1, respectively. The bacteria identified were Pseudomonas sp., Bacillus sp., Klebsiella sp., Staphylococcus sp., and Proteus sp. The study verified that a two-stage composting system is effective in treating the STBS. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Engineering and adaptive evolution of Escherichia coli W for L-lactic acid fermentation from molasses and corn steep liquor without additional nutrients.

    Science.gov (United States)

    Wang, Yongze; Li, Kunpeng; Huang, Feng; Wang, Jinhua; Zhao, Jinfang; Zhao, Xiao; Garza, Erin; Manow, Ryan; Grayburn, Scott; Zhou, Shengde

    2013-11-01

    The D-lactic acid producing strain, Escherichia coli HBUT-D, was reengineered for L(+)-lactic acid fermentation by replacing the D-lactate dehydrogenase gene (ldhA) with an L(+)-lactate dehydrogenase gene (ldhL) from Pedicoccus acidilactici, followed by adaptive evolution in sucrose. The resulting strain, WYZ-L, has enhanced expression of the sucrose operon (cscA and cscKB). In 100 g L(-1) of sucrose fermentation using mineral salt medium, WYZ-L produced 97 g L(-1) of l(+)-lactic acid, with a yield of 90%, a maximum productivity of 3.17 g L(-1)h(-1) and an optical purity of greater than 99%. In fermentations using sugarcane molasses and corn steep liquor without additional nutrients, WYZ-L produced 75 g L(-1) of l(+)-lactic acid, with a yield of 85%, a maximum productivity of 1.18 g L(-1)h(-1), and greater than 99% optical purity. These results demonstrated that WYZ-L has the potential to use waste molasses and corn steep liquor as a resource for L(+)-lactic acid fermentation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Soil nutrients, aboveground productivity and vegetative diversity after 10 years of experimental acidification and base cation depletion

    Science.gov (United States)

    Mary Beth Adams; James A. Burger

    2010-01-01

    Soil acidification and base cation depletion are concerns for those wishing to manage central Appalachian hardwood forests sustainably. In this research, 2 experiments were established in 1996 and 1997 in two forest types common in the central Appalachian hardwood forests, to examine how these important forests respond to depletion of nutrients such as calcium and...

  6. Experimental investigation on the absorption of alcoholic additives in an aqueous lithium bromide solution

    Energy Technology Data Exchange (ETDEWEB)

    Lonardi, Federico; Luke, Andrea [Kassel Univ. (Germany). Fachgebiet Technische Thermodynamik

    2015-07-01

    The increasing energy consumption and the scarcity of energy sources require an optimization of all technical processes. Absorption chillers represent a promising technology in order to provide a cooling demand with low-energy consumption. Indeed, such chillers are driven by low-temperature heat which is often available as waste heat from industrial processes, or can be obtained by the mean of solar collectors. On the other side, absorption chillers are not yet competitive with traditional compression chiller because of their low efficiency and reliability. One way to increase the efficiency of these chillers is by the means of additives. When added in small quantities to the working fluid, they reduce the surface tension, promoting Marangoni convection at the interface of the tube bundle of the absorber. As a consequence, the heat and mass transfer is enhanced. Although several investigations have been carried out in literature, only two kinds of additives are mostly investigated. Nevertheless, enhancement mechanism is not yet fully understood, and different theories have been proposed. In the present work, the influence of additives on the dynamic surface tension of aqueous lithium bromide solution is investigated. Common additives (2-ethylhexanol and 1-octanol) as well as new additives (3-phenyl-1-propan, 3,5,5-trymethyl-1-hexanol) are used. Surface tension is measured by the pendant-drop method. Different parameters, such as additive concentration and surrounding atmosphere, are varied during the experiment. Among the four additives investigated, 2-ethylhexanol shows the fastest absorption rate, while 3-phenyl-1-propanol has no influence in reducing the surface tension. The current study is carried out in the framework of the ITN Marie Curie ''SHINE'' research program financed by the EU.

  7. Effect of Nanofiller Addition to an Experimental Dentin Adhesive on Microtensile Bond Strength to Human Dentin

    Directory of Open Access Journals (Sweden)

    SH. Kasraei

    2009-06-01

    Full Text Available Objective: The purpose of the study was to evaluate the influence of adding nanofiller particles to a dentin bonding agent on resin-dentin bond strength.Materials and Methods: Fifty-four human intact premolar teeth were divided in to 6 groups of nine. The teeth were ground on occlusal surfaces and polished with 320 and then 600 grit silicon carbide papers. An experimental bonding system based on acetone/alcoholsolvent was provided with filler contents of 0.0, 0.5, 1.0, 2.5, 5.0, and 10.0 weight percent fumed silica nanofiller. After dentin surface etching, rinsing and blot drying, the experimentalbonding agents were applied to dentin surface. A composite resin was, then,bonded to the dentin on the bonding agent. The specimens were thermocycled for 500 cycles and sectioned in stick form. After two week of storage in distilled water, resin-dentin microtensile bond strength of the specimens was measured. Data were analyzed by one way ANOVA and DunnettT3 tests.Results: Bond strength to dentin was significantly affected by the filler level. Minimum and maximum resin-microtensile bond strength was in the experimental bonding agent with no filler (5.88 MPa and with filler level of 1.0 weight percent (15.15 MPa, respectively,and decreased with the increase of filler content down to 8.95 MPa for the filler level of 10.0 weight percent.Conclusion: Filler content seems to be one of the important factors influencing the bond strength of dental adhesives. Maximum dentin bond strength was obtained with 1% silanized nanofiller silica added to experimental adhesive system.

  8. Groundwater-derived nutrient and trace element transport to a nearshore Kona coral ecosystem: Experimental mixing model results

    Science.gov (United States)

    Prouty, Nancy G.; Swarzenski, Peter W.; Fackrell, Joseph; Johannesson, Karen H.; Palmore, C. Diane

    2017-01-01

    Study regionThe groundwater influenced coastal waters along the arid Kona coast of the Big Island, Hawai’i.Study focusA salinity-and phase partitioning-based mixing experiment was constructed using contrasting groundwater endmembers along the arid Konacoast of the Big Island, Hawai’i and local open seawater to better understand biogeochemical and physicochemical processes that influence the fate of submarine groundwater discharge (SGD)-derived nutrients and trace elements.New Hydrological Insights for the RegionTreated wastewater effluent was the main source for nutrient enrichment downstream at the Honokōhau Harbor site. Conservative mixing for some constituents, such as nitrate + nitrite, illustrate the effectiveness of physical mixing to maintain oceanic concentrations in the colloid (0.02–0.45 μm) and truly dissolved (

  9. Shrub canopies influence soil temperatures but not nutrient dynamics: An experimental test of tundra snow–shrub interactions

    Science.gov (United States)

    Myers-Smith, Isla H; Hik, David S

    2013-01-01

    Shrubs are the largest plant life form in tundra ecosystems; therefore, any changes in the abundance of shrubs will feedback to influence biodiversity, ecosystem function, and climate. The snow–shrub hypothesis asserts that shrub canopies trap snow and insulate soils in winter, increasing the rates of nutrient cycling to create a positive feedback to shrub expansion. However, previous work has not been able to separate the abiotic from the biotic influences of shrub canopies. We conducted a 3-year factorial experiment to determine the influences of canopies on soil temperatures and nutrient cycling parameters by removing ∼0.5 m high willow (Salix spp.) and birch (Betula glandulosa) shrubs, creating artificial shrub canopies and comparing these manipulations to nearby open tundra and shrub patches. Soil temperatures were 4–5°C warmer in January, and 2°C cooler in July under shrub cover. Natural shrub plots had 14–33 cm more snow in January than adjacent open tundra plots. Snow cover and soil temperatures were similar in the manipulated plots when compared with the respective unmanipulated treatments, indicating that shrub canopy cover was a dominant factor influencing the soil thermal regime. Conversely, we found no strong evidence of increased soil decomposition, CO2 fluxes, or nitrate or ammonia adsorbtion under artificial shrub canopy treatments when compared with unmanipulated open tundra. Our results suggest that the abiotic influences of shrub canopy cover alone on nutrient dynamics are weaker than previously asserted. PMID:24198933

  10. An Experimental Examination of Combustion of Isolated Liquid Fuel Droplets with Polymeric and Nanoparticle Additives

    Science.gov (United States)

    Ghamari, Mohsen

    In spite of recent attention to renewable sources of energy, liquid hydrocarbon fuels are still the main source of energy for industrial and transportation systems. Manufactures and consumers are consistently looking for ways to optimize the efficiency of fuel combustion in terms of cost, emissions and consumer safety. In this regard, increasing burning rate of liquid fuels has been of special interest in both industrial and transportation systems. Recent studies have shown that adding combustible nano-particles could have promising effects on improving combustion performance of liquid fuels. Combustible nano-particles could enhance radiative and conductive heat transfer and also mixing within the droplet. Polymeric additive have also shown promising effect on improving fire safety by suppressing spreading behavior and splatter formation in case of crash scenario. Polymers are also known to have higher burning rate than regular hydrocarbon fuels. Therefore adding polymeric additive could have the potential to increase the burning rate. In this work, combustion dynamics of liquid fuel droplets with both polymeric and nanoparticle additives is studied in normal gravity. High speed photography is employed and the effect of additive concentration on droplet burning rate, burning time, extinction and soot morphology is investigated. Polymer added fuel was found to have a volatility controlled combustion with four distinct regimes. The first three zones are associated with combustion of base fuel while the polymer burns last and after a heating zone because of its higher boiling point. Polymer addition reduces the burning rate of the base fuel in the first zone by means of increasing viscosity and results in nucleate boiling and increased burning rates in the second and third stages. Overall, polymer addition resulted in a higher burning rate and shorter burning time in most of the scenarios. Colloidal suspensions of carbon-based nanomaterials in liquid fuels were also

  11. Shock-implanted noble gases. II - Additional experimental studies and recognition in naturally shocked terrestrial materials

    Science.gov (United States)

    Bogard, Donald; Horz, Friedrich; Johnson, Pratt

    1989-01-01

    The process by which ambient gases can be implanted into silicates by shocks was investigated by analyzing the noble-gas content of several experimentally and naturally shocked silicate samples. The retentivity of shock-implanted gas during stepwise heating in the laboratory was defined in terms of two parameters, namely, the activation energy for diffusion and the extraction temperature at which 50 percent of the gas is released, both of which correlate with the shock pressure. The experiments indicate that, with increasing shock pressure, gas implantation occurs through an increasing production of microcracks/defects in the silicate lattice. The degree of annealing of these defects control the degree of diffusive loss of implanted gas.

  12. Impact of ocean acidification on phytoplankton assemblage, growth, and DMS production following Fe-dust additions in the NE Pacific high-nutrient, low-chlorophyll waters

    Science.gov (United States)

    Mélançon, Josiane; Levasseur, Maurice; Lizotte, Martine; Scarratt, Michael; Tremblay, Jean-Éric; Tortell, Philippe; Yang, Gui-Peng; Shi, Guang-Yu; Gao, Huiwang; Semeniuk, David; Robert, Marie; Arychuk, Michael; Johnson, Keith; Sutherland, Nes; Davelaar, Marty; Nemcek, Nina; Peña, Angelica; Richardson, Wendy

    2016-03-01

    Ocean acidification (OA) is likely to have an effect on the fertilizing potential of desert dust in high-nutrient, low-chlorophyll oceanic regions, either by modifying iron (Fe) speciation and bioavailability or by altering phytoplankton Fe requirements and acquisition. To address this issue, short incubations (4 days) of northeast subarctic Pacific waters enriched with either FeSO4 or dust and set at pH 8.0 (in situ) and 7.8 were conducted in August 2010. We assessed the impact of a decrease in pH on dissolved Fe concentration, phytoplankton biomass, taxonomy and productivity, and the production of dimethylsulfide (DMS) and its algal precursor dimethylsulfoniopropionate (DMSP). Chlorophyll a (chl a) remained unchanged in the controls and doubled in both the FeSO4-enriched and dust-enriched incubations, confirming the Fe-limited status of the plankton assemblage during the experiment. In the acidified treatments, a significant reduction (by 16-38 %) in the final concentration of chl a was measured compared to their nonacidified counterparts, and a 15 % reduction in particulate organic carbon (POC) concentration was measured in the dust-enriched acidified treatment compared to the dust-enriched nonacidified treatment. FeSO4 and dust additions had a fertilizing effect mainly on diatoms and cyanobacteria as estimated from algal pigment signatures. Lowering the pH affected mostly the haptophytes, but pelagophyte concentrations were also reduced in some acidified treatments. Acidification did not significantly alter DMSP and DMS concentrations. These results show that dust deposition events in a low-pH iron-limited northeast subarctic Pacific are likely to stimulate phytoplankton growth to a lesser extent than in today's ocean during the few days following fertilization and point to a low initial sensitivity of the DMSP and DMS dynamics to OA.

  13. Electrolyte addition to nonionic contrast media. Cardiac effects during experimental coronary arteriography.

    Science.gov (United States)

    Pedersen, H K

    1996-01-01

    Although the incidence of serious adverse effects is low during clinical coronary arteriography, life-threatening cardiovascular complications occasionally occur. Ventricular fibrillation (VF) is most often seen during contrast media (CM) injection through a wedged catheter. A simulated wedged catheter model in dogs has therefore been developed. Further, patients with heart failure are at greater risk for CM-related side effects during coronary arteriography. Thus, an acute ischemic heart failure model has been used. The present thesis was designed to investigate the cardiac electrophysiologic and hemodynamic effects of CM during selective coronary arteriography in normal and failing hearts, and in particular the role of electrolyte addition to nonionic CM. The risk of spontaneously induced VF and the arrhythmogenic mechanisms were studied when using iso-osmolal and low-osmolal CM having different contents of electrolytes, and after pretreatment with antiarrhythmic drugs. Further, effects of adding electrolytes to nonionic CM during single and fast repeated injections in normal and failing hearts were studied. Also possible effects of oxygenating CM were studied. CM injection in a wedged catheter situation had a high risk for VF. Probably, VF was due to induced regional electrophysiologic changes in ventricular activation and repolarization. Pretreatment with antiarrhythmic drugs did not prevent VF. However, addition of low concentrations of electrolytes to nonionic CM reduced the risk for VF in a wedged catheter situation. The results indicate that side-effects of CM during coronary arteriography are related mainly to the passive washout of cardiac electrolytes. Electrolyte shifts during coronary arteriography may change the myocardial Na/Ca balance and cellular calcium control. The nonionic, iso-osmolal CM iodixanol, with a balanced content of sodium and calcium and the low-osmolal, nonionic CM iohexol, also with a balanced content of electrolytes, had about the

  14. Modernization at the Y-12 National Security Complex: A Case for Additional Experimental Benchmarks

    Energy Technology Data Exchange (ETDEWEB)

    Thornbury, M. L. [Y-12 National Security Complex, Oak Ridge, TN (United States); Juarez, C. [Y-12 National Security Complex, Oak Ridge, TN (United States); Krass, A. W. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2017-08-14

    Efforts are underway at the Y-12 National Security Complex (Y-12) to modernize the recovery, purification, and consolidation of un-irradiated, highly enriched uranium metal. Successful integration of advanced technology such as Electrorefining (ER) eliminates many of the intermediate chemistry systems and processes that are the current and historical basis of the nuclear fuel cycle at Y-12. The cost of operations, the inventory of hazardous chemicals, and the volume of waste are significantly reduced by ER. It also introduces unique material forms and compositions related to the chemistry of chloride salts for further consideration in safety analysis and engineering. The work herein briefly describes recent investigations of nuclear criticality for 235UO2Cl2 (uranyl chloride) and 6LiCl (lithium chloride) in aqueous solution. Of particular interest is the minimum critical mass of highly enriched uranium as a function of the molar ratio of 6Li to 235U. The work herein also briefly describes recent investigations of nuclear criticality for 235U metal reflected by salt mixtures of 6LiCl or 7LiCl (lithium chloride), KCl (potassium chloride), and 235UCl3 or 238UCl3 (uranium tri-chloride). Computational methods for analysis of nuclear criticality safety and published nuclear data are employed in the absence of directly relevant experimental criticality benchmarks.

  15. Biogas Production Experimental Research by Using Sewage Sludge Loading with Biochar Additive

    Directory of Open Access Journals (Sweden)

    Vitalij Kolodynskij

    2017-09-01

    Full Text Available Biogas – ecological fuel, which is assigned to alternative energy sources. It should be noted, that biogas – renewable energy source, which does not require any specific climatic conditions or geographical position of a country. This power source is available and can be successfully produced and used in all countries of the world. The main components of biogas – methane CH4 and carbon monoxide CO2. This gas is formed under anaerobic conditions, when microorganisms decompose biodegradable biomass. In biological sciences biomass means a living matter content, expressed in grams per unit area. Meanwhile, in the energy sector, the definition of biomass is limited and biomass is characterized as fuel source, produced from plant materials and organic waste (food waste, wood, sludge, manure, vegetables, etc.. Currently, to produce biogas from biomass, bioreactors are used worldwide. However, in order to increase the quality and yield of biogas, in the world practice various bioload additives are used: vegetable waste, clay minerals, and a large amount of the protein-containing waste. The goal – to evaluate the impact of biochar on biogas quality and yield using sewage sludge load. It was found, that 10% biochar additive increased average CH4 concentration of 7.9%, reduced the CO2 concentration of 3–4% and totally removed H2S from biogas.

  16. Experimental study of wood shaving addition in mortar and statistical modeling on selected effects

    Science.gov (United States)

    Sotiropoulou, Anastasia; Gavela, Stamatia; Nikoloutsopoulos, Nikolaos; Passa, Dimitra; Papadakos, Georgios

    2017-04-01

    In the frame of an extended research program dealing with wood shavings utilization in mortar, a set of procedures were developed for verifying effects of wood shavings addition to specific mortar properties. Mixes containing wood shavings replacing fine aggregates by 0, 30, 50 and 70% of their volume were made. Workability, fresh mortar unit weight, ultrasonic pulse velocity (UPV) and flexural and compressive strength were determined, based on measurements, at various curing ages. Measurement results and analysis suggest that compressive strength reduction caused by wood shavings addition could be predicted. The outcome was standardized in the form of a multifactorial sigmoidal model. It was also made evident that the mix proportion of cement increases when wood shavings are used as a by volume replacement of conventional fine aggregates, due to the low value of specific gravity of wood compared to conventional aggregates. Another procedure is suggested based on mass and volume measurements aiming at the verification of the mix proportions in the final mortar mixture.

  17. Performance of broilers experimentally inoculated with Salmonella Typhimurium and fed diets with addition of lactulosis

    Directory of Open Access Journals (Sweden)

    Eliete Souza Santana

    2012-08-01

    Full Text Available The objective of this experiment was to evaluate the influence of lactulose on performance as well as its ability to prevent colonization by Salmonella Typhimurium in broilers orally inoculated with this pathogen. The design adopted was completely randomized, with 630 one-day-old male chicks distributed into six treatments, with seven replications and 15 birds per experimental unit. The treatments comprised the following procedures: T1 (control group - no S. Typhimurium inoculation or supply of lactulosis; T2 - only inoculation of S. Typhimurium; T3 - only lactulosis supply; T4 supply of lactulosis and S. Typhimurium inoculation on the first day of life; T5 - supply of lactulosis 48 hours before S. Typhimurium inoculation; and T6 - supply of lactulosis 48 hours after inoculation of S. Typhimurium. Performance variables were evaluated on the seventh, 14th, 21st and 28th days of age; fragments of the duodenum and jejunum were collected and sent to histomorphometric assessment at 14 days of age, and S. Typhimurium excretion was verified in cloacal swabs on the 10th, 24th and 35th days of age. Performance data were analyzed by ANOVA and Tukey's test (5% and fecal excretion data were assessed by non-parametric chi-square test. Better weight gain and feed conversion were observed in groups fed lactulosis with or without challenge of S. Typhimurium up to 21 days of age. Reduced duodenum villous height was verified on the 14th day in groups challenged with the pathogen. Reduction of S. Typhimurium fecal excretion was verified in broilers fed lactulosis from the first day of life on and 48 hours before receiving S. Typhimurium directly into the crop. Lactulosis increases broiler performance up to one week after its inoculation, influences duodenum villous height and reduces the fecal excretion of Salmonella Typhimurium.

  18. Effect of nanoclay addition on physical, chemical, optical and biological properties of experimental dental resin composites.

    Science.gov (United States)

    Munhoz, Tais; Fredholm, Yann; Rivory, Pascaline; Balvay, Sandra; Hartmann, Daniel; da Silva, Pedro; Chenal, Jean-Marc

    2017-03-01

    To prepare organically modified montmorillonite (OM MMT) and assess mechanical, physical, chemical and biological effects of its introduction into resin-composites. Natural MMT clay was modified by a methacrylate functionalized quaternary ammonium intercalating agent. Interlayer distance was measured by X-ray diffraction. Dental composites were then prepared with x=0, 1, 2.5, 5 or 7.5wt.% of OM MMT, (75-x) wt.% of silanated barium glass and 25wt.% of methacrylate based matrix). Relative weight loss was measured and the effect of the substitution on mechanical properties was studied by dynamic mechanical analysis and hardness tests. Properties of resin composites were evaluated in terms of water sorption, light transmittance, biological tests and by high-performance liquid chromatography (HPLC). Resin based composites with well-dispersed organically modified MMT were successfully prepared. There were no significant weight loss differences shown by TGA within all samples. The DMA analysis showed that the introduction of clays have a beneficial effect in increasing the storage and elastic modulus of composites. Clay presence was shown to interfere with the blue light transmittance, affecting Vickers hardness and water sorption levels. The amount of released monomers measured from extracts was below expected levels for this type of materials and biological tests show satisfactory cell compatibility. This paper reports the successful functionalization of MMT by a methacrylate group and further incorporation in experimental dental composites. Physical and biological results show a potential interest to the application of nanoclays into dental resin composites. Copyright © 2016. Published by Elsevier Ltd.

  19. Experimental Analysis of Performance of Diesel Engine Using Kusum Methyl Ester With Diethyl Ether as Additive

    Directory of Open Access Journals (Sweden)

    Sandip S. Jawre,

    2014-05-01

    Full Text Available The fossile fuels are widely used in diesel engine and continually depleting with increasing consumption and prices day by day. The fatty acid methyl ester has become an effective alternative to diesel. Various types of vegetable oil such as Jatropha, karanja, cottonseed, neem, sunflower, palm, mahuva, coconut etc. can be used as fuel in diesel engine. Kusum oil is one of the fuel used in present work. The viscosity of kusum oil is very high, so it was reduced by Transesterification process. This study presents effect of diethyl ether as additive to biodiesel of kusum (schliechera oleosa methyl ester on the performance and emission of diesel engine at different load and constant speed and two different injection pressure (170 and 190 bar. From literature it was observed that very few studies had been conducted on use of neat biodiesel and diethyl ether blends and use of kusum methyl ester (KME in diesel engine found to be very less as compared to different biodiesel. Hence this topic was taken under study. The fuels and its blends used are 100% diesel, B100 (100% KME, BD-1 (95% KME, 5% DEE, BD-2 (90% KME, 10% DEE, BD-3 (85% KME, 15% DEE respectively. It was observed that the performance of engine increases at high injection pres-sure. The results indicate that lower BSFC was observed with BD-3 as compared to B100, BD-1 and BD-2. Brake thermal efficiency of BD-3 decreased at 170 bar injection pressure but it increase at 190 bar. Drastic re-duction in smoke is observed with all blends at higher engine loads. DEE addition to biodiesel reflects better engine performance compared to neat biodiesel.

  20. Pengaruh Penggunaan High Quality Feed Supplement terhadap Konsumsi dan Kecernaan Nutrien Sapi Perah Awal Laktasi (The Effect of High Quality Feed Supplement Addition on the Nutrient Consumption and Digestibility of Early Lactating Dairy Cow

    Directory of Open Access Journals (Sweden)

    Andriyani Astuti

    2012-02-01

    (73.11%, and K (70.69% on BETN. The conclusion was that the addition of HQFS of first lactation dairy cow would increase nutrient consumption and crude protein and nitrogen-free extract digestibility. (Key words: High quality feed supplement, Dairy cow, Consumption, Digestibility

  1. Analysis of the laser powder bed fusion additive manufacturing process through experimental measurement and finite element modeling

    Science.gov (United States)

    Dunbar, Alexander Jay

    The objective in this work is to provide rigourous experimental measurements to aid in the development of laser powder bed fusion (LPBF) additive manufacturing (AM). A specialized enclosed instrumented measurement system is designed to provide in situ experimental measurements of temperature and distortion. Experiments include comparisons of process parameters, materials and LPBF machines. In situ measurements of distortion and temperature made throughout the build process highlight inter-layer distortion effects previously undocumented for laser powder bed fusion. Results from these experiments are also be implemented in the development and validation of finite element models of the powder bed build process. Experimental analysis is extended from small-scale to larger part-scale builds where experimental post-build measurements are used in analysis of distortion profiles. Experimental results provided from this study are utilized in the validation of a finite element model capable of simulating production scale parts. The validated finite element model is then implemented in the analysis of the part to provide information regarding the distortion evolution process. A combination of experimental measurements and simulation results are used to identify the mechanism that results in the measured distortion profile for this geometry. Optimization of support structure primarily focuses on the minimization of material use and scan time, but no information regarding failure criteria for support structure is available. Tensile test samples of LPBF built support structure are designed, built, and tested to provide measurements of mechanical properties of the support structure. Experimental tests show that LPBF built support structure has only 30-40% of the ultimate tensile strength of solid material built in the same machine. Experimental measurement of LPBF built support structure provides clear failure criteria to be utilized in the future design and implementation of

  2. An Experimental Investigation into Additive Manufacturing-Induced Residual Stresses in 316L Stainless Steel

    Science.gov (United States)

    Wu, Amanda S.; Brown, Donald W.; Kumar, Mukul; Gallegos, Gilbert F.; King, Wayne E.

    2014-12-01

    Additive manufacturing (AM) technology provides unique opportunities for producing net-shape geometries at the macroscale through microscale processing. This level of control presents inherent trade-offs necessitating the establishment of quality controls aimed at minimizing undesirable properties, such as porosity and residual stresses. Here, we perform a parametric study into the effects of laser scanning pattern, power, speed, and build direction in powder bed fusion AM on residual stress. In an effort to better understand the factors influencing macroscale residual stresses, a destructive surface residual stress measurement technique (digital image correlation in conjunction with build plate removal and sectioning) has been coupled with a nondestructive volumetric evaluation method ( i.e., neutron diffraction). Good agreement between the two measurement techniques is observed. Furthermore, a reduction in residual stress is obtained by decreasing scan island size, increasing island to wall rotation to 45 deg, and increasing applied energy per unit length (laser power/speed). Neutron diffraction measurements reveal that, while in-plane residual stresses are affected by scan island rotation, axial residual stresses are unchanged. We attribute this in-plane behavior to misalignment between the greatest thermal stresses (scan direction) and largest part dimension.

  3. A comparative experimental study of steel fibre-additive reinforced concrete beams

    Directory of Open Access Journals (Sweden)

    Altun, F.

    2004-12-01

    Full Text Available Five different batches of class C20 concrete, containing Dramix-RC-80/60-BN steel fibers (SFs as additives at doses of 0, 30, 40, 50 and 60 kg/m3, and six Ø 15x30 cm prisms were poured from each batch. Standard crushing tests were run on all the specimens and the respective load-displacement and stress-strain curves were plotted. Toughness, ultimate compressive strength and the modulus of elasticity were determined for all specimens. The compressive strength and modulus of elasticity declined in 30 kg/m3 steel-fiber-additive concrete (SFAC by 9% and 7% compared to the reference C20 concrete without SFs, and the area under the load-deflection curve grew more than twofold. In concrete with a higher SF dosage, the differences in strength and elasticity were around I0% whilst toughness was about the same. Because toughness values were similar in 30, 40, 50 and 60 kg/m3 plain SF-additive concrete and the strength and modulus of elasticity were slightly better in the mixes with the smallest proportion of SF for reasons of economy, 30 kg/m3 was taken as the optimum dose of steel fiber to be added to the reinforced concrete used in a second phase of the study. Hence, of the six reinforced concrete (RC beams made, all of equal size and with the same under-reinforced tensile reinforcement design, three were made with concrete containing the above-mentioned dose of SF. In addition to compressive strength, these beams were tested for flexural strength, which was found to be 18% greater for the SFARC beams than the ordinary RC beams, and the upper arms of the load versus mid-span deflection curves prior to ultimate failure of the SFARC beams were considerably longer than the same arms on the curves for ordinary RC beams.

    Se han utilizado cinco lotes diferentes de hormigón clase C20 cuatro de ellos con fibras de acero (FA, identificadas como Dramix-CR-80/60-BN, en cuatro proporciones diferentes: 30, 40, 50 y 60 kg/m3 y el quinto exento de

  4. Experimental biofilms within drinking water treatment plant origin; evaluation of nutrient concentration and temperature influences upon their development

    Directory of Open Access Journals (Sweden)

    Anca FARKAS

    2009-11-01

    Full Text Available From the planktonic free-floating state, microorganisms pass to the solid state, the biofilm, cells being strongly attached to each other and usually to the interface. This changing in cells’ behavior induces surface colonization and complex interactions development within the biofilm. If the biofilm’s role into the natural aquatic habitats is, undoubtedly, a positive one, consisting in water self-purification, drinking water pipe networks biofouling can be responsible for a wide range of water quality and operational problems. This exploratory experiment was performed in order to investigate, in a time interval of 7 days, the influence of certain environmental factors such as nutrient concentration and temperature upon in vitro biofilm’s development, origin in the biofilm of water treatment plant. The method used for in vitro biofilm growth monitoring is the colorimetric measurement of the biomass. Descriptive analyses, including the mean value, variability, trends, correlations and graphic displays were performed. The correlation analysis shown that the biofilm development in the discussed experiment was influenced as by the origin source as by the temperature, time and nutrients concentration. The biomass increment was significantly different for the biofilms with clarifier and sand filter sites origin, grown at 22 oC, while at 8 oC, the differences were not significant from a statistical point of view. For all the dilutions, moments and temperatures considered, the biofilm’s development with clarifier origin registered was significantly higher than the biofilm with sand filter origin.

  5. Additive impacts of experimental climate change increase risk to an ectotherm at the Arctic's edge

    Science.gov (United States)

    Davenport, Jon M.; Hossack, Blake R.; Fishback, LeeAnn

    2017-01-01

    Globally, Arctic and Subarctic regions have experienced the greatest temperature increases during the last 30 years. These extreme changes have amplified threats to the freshwater ecosystems that dominate the landscape in many areas by altering water budgets. Several studies in temperate environments have examined the adaptive capacity of organisms to enhance our understanding of the potential repercussions of warming and associated accelerated drying for freshwater ecosystems. However, few experiments have examined these impacts in Arctic or Subarctic freshwater ecosystems, where the climate is changing most rapidly. To evaluate the capacity of a widespread ectotherm to anticipated environmental changes, we conducted a mesocosm experiment with wood frogs (Rana sylvatica) in the Canadian Subarctic. Three warming treatments were fully crossed with three drying treatments to simulate a range of predicted changes in wetland environments. We predicted wetland warming and drying would act synergistically, with water temperature partially compensating for some of the negative effects of accelerated drying. Across all drying regimes, a 1 °C increase in water temperature increased the odds of survival by 1.79, and tadpoles in 52-day and 64-day hydroperiod mesocosms were 4.1–4.3 times more likely to survive to metamorphosis than tadpoles in 45-day mesocosms. For individuals who survived to metamorphosis, there was only a weak negative effect of temperature on size. As expected, increased temperatures accelerated tadpole growth through day 30 of the experiment. Our results reveal that one of the dominant herbivores in Subarctic wetlands, wood frog tadpoles, are capable of increasing their developmental rates in response to increased temperature and accelerated drying, but only in an additive manner. The strong negative effects of drying on survival, combined with lack of compensation between these two environmental drivers, suggest changes in the aquatic environment

  6. Protective nutrients.

    Science.gov (United States)

    Levy, Joseph; Turkish, Aaron

    2002-11-01

    Recognition that specific nutrients can be beneficial when consumed in amounts above the accepted daily requirements has provided a major impetus for the critical examination of dietary approaches with single or multiple nutrient supplements chosen to modulate the inflammatory response, enhance immune function, or improve the blood-gut barrier. Patients suffering the effects of hypercatabolism caused by surgery, cancer, or extensive burns are prime candidates for immunonutrition, as the intervention has come to be known, as are immunosuppressed patients with the human immunodeficiency virus or other overwhelming infections. This review focuses on key nutrients used in clinical trials for which a body of information on the mode of action and metabolic pathways is available. The topics covered include the amino acids, glutamine and arginine; omega-3 fatty acids, eicosapentaenoic acid and docosahexanoic acid; vitamin A; and zinc. Lastly, we address the area of pre- and probiotics and how "friendly" microorganisms are being incorporated into therapeutic regimens aimed at sustaining health. The use of immunonutrition requires judicious consideration of the potential undesirable effects of certain additives in clinical settings where enhanced immune responsiveness can translate into tissue damage and altered mucosal defenses.

  7. Forest soil nutrient status after 10 years of experimental acidification and base cation depletion : results from 2 long-term soil productivity sites in the central Appalachians

    Energy Technology Data Exchange (ETDEWEB)

    Adams, M.B. [United States Dept. of Agriculture Forest Service, Parsons, WV (United States); Burger, J.A. [Virginia Tech University, Blacks Burg, VA (United States)

    2010-07-01

    This study assessed the hypothesis that soil based cation depletion is an effect of acidic deposition in forests located in the central Appalachians. The effects of experimentally induced base cation depletion were evaluated in relation to long-term soil productivity and the sustainability of forest stands. Whole-tree harvesting was conducted along with the removal of dead wood litter in order to remove all aboveground nutrients. Ammonium sulfate fertilizer was added at annual rates of 40.6 kg S/ha and 35.4 kg N/h in order to increase the leaching of calcium (Ca) and magnesium (Mg) from the soil. A randomized complete block design was used in 4 or 5 treatment applications in a mixed hardwood experimental forest located in West Virginia and in a cherry-maple forest located in a national forest in West Virginia. Soils were sampled over a 10-year period. The study showed that significant changes in soil Mg, N and some other nutrients occurred over time. However, biomass did not differ significantly among the different treatment options used.

  8. Effects of common carp Cyprinus carpio (L.) and feed addition in rohu Labeo rohita (Hamilton) ponds on nutrient partitioning among fish, plankton and benthos

    NARCIS (Netherlands)

    Rahman, M.M.; Verdegem, M.C.J.; Nagelkerke, L.A.J.; Wahab, M.A.; Milstein, A.; Verreth, J.A.J.

    2008-01-01

    The effects of introducing common carp (CC) and of adding artificial feed to fertilized rohu ponds on water quality and nutrient accumulation efficiency were studied. All ponds were stocked with 15 000 rohu ha¿1. Treatments included ponds with rohu alone, rohu plus 5000 common carp ha¿1 and rohu

  9. Improving ebpr stability in wwtps aiming at simultaneous carbon and nutrient removal: from modelling studies to experimental validation

    OpenAIRE

    Guerrero Camacho, Francisco Javier

    2014-01-01

    L'eliminació biològica de nutrients (EBN) a les estacions depuradores d'aigües residuals (EDARs) es considera el procés més rentable y mediambientalment més respectuós per a prevenir l'eutrofització i complir amb els cada cop més restrictius límits d'abocament. L'eliminació biològica de nitrogen (N) ha estat àmpliament estudiada i implementada en nombroses EDARs, tant urbanes com industrials. Contràriament, per a l'eliminació biològica de fòsfor, P, (procés EBPR) no existeixen encara molt exe...

  10. Impact of Temperature and Nutrients on Carbon: Nutrient Tissue Stoichiometry of Submerged Aquatic Plants: An Experiment and Meta-Analysis.

    Science.gov (United States)

    Velthuis, Mandy; van Deelen, Emma; van Donk, Ellen; Zhang, Peiyu; Bakker, Elisabeth S

    2017-01-01

    Human activity is currently changing our environment rapidly, with predicted temperature increases of 1-5°C over the coming century and increased nitrogen and phosphorus inputs in aquatic ecosystems. In the shallow parts of these ecosystems, submerged aquatic plants enhance water clarity by resource competition with phytoplankton, provide habitat, and serve as a food source for other organisms. The carbon:nutrient stoichiometry of submerged aquatic plants can be affected by changes in both temperature and nutrient availability. We hypothesized that elevated temperature leads to higher carbon:nutrient ratios through enhanced nutrient-use efficiency, while nutrient addition leads to lower carbon:nutrient ratios by the luxurious uptake of nutrients. We addressed these hypotheses with an experimental and a meta-analytical approach. We performed a full-factorial microcosm experiment with the freshwater plant Elodea nuttallii grown at 10, 15, 20, and 25°C on sediment consisting of pond soil/sand mixtures with 100, 50, 25, and 12.5% pond soil. To address the effect of climatic warming and nutrient addition on the carbon:nutrient stoichiometry of submerged freshwater and marine plants we performed a meta-analysis on experimental studies that elevated temperature and/or added nutrients (nitrogen and phosphorus). In the microcosm experiment, C:N ratios of Elodea nuttallii decreased with increasing temperature, and this effect was most pronounced at intermediate nutrient availability. Furthermore, higher nutrient availability led to decreased aboveground C:P ratios. In the meta-analysis, nutrient addition led to a 25, 22, and 16% reduction in aboveground C:N and C:P ratios and belowground C:N ratios, accompanied with increased N content. No consistent effect of elevated temperature on plant stoichiometry could be observed, as very few studies were found on this topic and contrasting results were reported. We conclude that while nutrient addition consistently leads to

  11. Impact of Temperature and Nutrients on Carbon: Nutrient Tissue Stoichiometry of Submerged Aquatic Plants: An Experiment and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Mandy Velthuis

    2017-05-01

    Full Text Available Human activity is currently changing our environment rapidly, with predicted temperature increases of 1–5°C over the coming century and increased nitrogen and phosphorus inputs in aquatic ecosystems. In the shallow parts of these ecosystems, submerged aquatic plants enhance water clarity by resource competition with phytoplankton, provide habitat, and serve as a food source for other organisms. The carbon:nutrient stoichiometry of submerged aquatic plants can be affected by changes in both temperature and nutrient availability. We hypothesized that elevated temperature leads to higher carbon:nutrient ratios through enhanced nutrient-use efficiency, while nutrient addition leads to lower carbon:nutrient ratios by the luxurious uptake of nutrients. We addressed these hypotheses with an experimental and a meta-analytical approach. We performed a full-factorial microcosm experiment with the freshwater plant Elodea nuttallii grown at 10, 15, 20, and 25°C on sediment consisting of pond soil/sand mixtures with 100, 50, 25, and 12.5% pond soil. To address the effect of climatic warming and nutrient addition on the carbon:nutrient stoichiometry of submerged freshwater and marine plants we performed a meta-analysis on experimental studies that elevated temperature and/or added nutrients (nitrogen and phosphorus. In the microcosm experiment, C:N ratios of Elodea nuttallii decreased with increasing temperature, and this effect was most pronounced at intermediate nutrient availability. Furthermore, higher nutrient availability led to decreased aboveground C:P ratios. In the meta-analysis, nutrient addition led to a 25, 22, and 16% reduction in aboveground C:N and C:P ratios and belowground C:N ratios, accompanied with increased N content. No consistent effect of elevated temperature on plant stoichiometry could be observed, as very few studies were found on this topic and contrasting results were reported. We conclude that while nutrient addition

  12. Utilização de uréia no resíduo desidratado de vitivinícola associado à palma forrageira na alimentação de caprinos: consumo e digestibilidade de nutrientes Addition of urea to dehydrated vineyards residue, associated with forage cactus in goats feeding: intake and nutrient digestibility

    Directory of Open Access Journals (Sweden)

    Manuela Silva Libanio Tosto

    2008-10-01

    Full Text Available Avaliou-se a influência da adição de 0; 0,5; 1 ou 1,5% de uréia no resíduo desidratado de vitivinícolas - utilizado em associação a palma forrageira na alimentação de caprinos - no consumo e na digestibilidade dos nutrientes. Foram utilizados 24 caprinos machos castrados, sem padrão racial definido, com peso vivo médio de 18 kg, distribuídos em blocos ao acaso, de acordo com o peso vivo. O período experimental foi de 20 dias: 15 para adaptação e 5 para coleta. A adição de teores crescentes de uréia ao resíduo desidratado de vitivinícola possibilitou aumento do consumo de matéria seca (MS, matéria orgânica (MO, proteína bruta (PB e fibra em detergente neutro (FDN, expressos em kg/dia, %PV e em g/kgPV0,75. Observou-se consumo linear crescente de nutrientes digest��veis totais (NDT, carboidratos totais (CT e carboidratos não-fibrosos (CNF, em %PV e g/kgPV0,75. Não houve diferença significativa nos consumos de NDT, CT e CNF expressos em kg/dia, cujos valores médios foram 0,363; 0,575 e 0,258, respectivamente. Entretanto, a adição de uréia ao resíduo não influenciou os coeficientes de digestibildade de MS, MO e FDN (médias de 48,13; 46,08 e de 20,37%, respectivamente. Os coeficientes de digestibilidade de CNF apresentaram crescimento linear, enquanto os de PB apresentaram comportamento quadrático, com valor máximo de 48,93%, com a adição de 1,3% de uréia ao resíduo. O uso de uréia no resíduo desidratado de vitivinícola elevou linearmente o consumo de nutrientes, contudo, o nível de 1,3% é o mais indicado, pois promove melhor digestibilidade da proteína bruta de dietas contendo esse alimento alternativo.The effect of the addition of 0.0, 0.5, 1.0 and 1.5% of urea to dehydrated vineyards residue, associated to forage cactus palm in the feeding of goats on intake and nutrient digestibility was evaluated. Twenty-four castrated crossbred goats, without defined breed, with average 18 kg of BW were

  13. Experimental investigation on wear resistance of a new cutting fluid using a four ball tribometer – optimization of additive percent

    Directory of Open Access Journals (Sweden)

    Paleu Viorel

    2017-01-01

    Full Text Available The cutting fluid manufacturers aim to obtain the best products at the lowest possible price. To achieve such a compromise experimental work is needed, trying to get the lowest allowed content of additive in the base oil. The paper presents the results of standard tests carried out on four ball machine. This tribometer is used to analyze the load-carrying properties of cutting fluids. The results are compared with the standard requirements, related to the measured wear scar on the three lower balls of the four ball device. An optimum of sulphur additive content into the base oil was found around 10%. According to the actual standards and following the results of carried-out tests, for this specific case the lowest acceptable content of additive is around 4%.

  14. Lack of Impact of Posidonia oceanica Leaf Nutrient Enrichment on Sarpa salpa Herbivory: Additional Evidence for the Generalist Consumer Behavior of This Cornerstone Mediterranean Herbivore.

    Science.gov (United States)

    Marco-Méndez, Candela; Wessel, Caitlin; Scheffel, Whitney; Ferrero-Vicente, Luis; Fernández-Torquemada, Yolanda; Cebrián, Just; Heck, Kenneth L; Sánchez-Lizaso, Jose Luis

    2016-01-01

    The fish Sarpa salpa (L.) is one of the main macroherbivores in the western Mediterranean. Through direct and indirect mechanisms, this herbivore can exert significant control on the structure and functional dynamics of seagrass beds and macroalgae. Past research has suggested nutritional quality of their diet influences S. salpa herbivory, with the fish feeding more intensively and exerting greater top down control on macrophytes with higher internal nutrient contents. However recent findings have questioned this notion and shown that herbivores do not preferentially feed on macrophytes with higher nutrient contents, but rather feed on a wide variety of them with no apparent selectivity. To contribute to this debate, we conducted a field fertilization experiment where we enriched leaves of the seagrass Posidonia oceanica, a staple diet for S. salpa, and examined the response by the herbivore. These responses included quantification of leaf consumption in fertilized and non-fertilized/control plots within the bed, and food choice assays where fertilized and non-fertilized/control leaves were simultaneously offered to the herbivore. Despite the duration of leaf exposure to herbivores (30 days) and abundant schools of S. salpa observed around the plots, leaf consumption was generally low in the plots examined. Consumption was not higher on fertilized than on non-fertilized leaves. Food choice experiments did not show strong evidence for selectivity of enriched leaves. These results add to a recent body of work reporting a broad generalist feeding behavior by S. salpa with no clear selectivity for seagrass with higher nutrient content. In concert, this and other studies suggest S. salpa is often generalist consumers not only dictated by diet nutrient content but by complex interactions between other traits of nutritional quality, habitat heterogeneity within their ample foraging area, and responses to predation risk.

  15. Nutrient Addition Leads to a Weaker CO2 Sink and Higher CH4 Emissions through Vegetation-Microclimate Feedbacks at Mer Bleue Bog, Canada

    Science.gov (United States)

    Bubier, J. L.; Arnkil, S.; Humphreys, E.; Juutinen, S.; Larmola, T.; Moore, T. R.

    2015-12-01

    Atmospheric nitrogen (N) deposition has led to nutrient enrichment in wetlands globally, affecting plant community composition, carbon (C) cycling, and microbial dynamics. Nutrient-limited boreal bogs are long-term sinks of carbon dioxide (CO2), but sources of methane (CH4), an important greenhouse gas. We fertilized Mer Bleue Bog, a Sphagnum moss and evergreen shrub-dominated ombrotrophic bog near Ottawa, Ontario, for 10-15 years with N as NO3 and NH4 at 5, 10 and 20 times ambient N deposition (0.6-0.8 g N m-2 y-1), with and without phosphorus (P) and potassium (K). Treatments were applied to triplicate plots (3 x 3 m) from May - August 2000-2015 and control plots received distilled water. We measured net ecosystem CO2 exchange (NEE), ecosystem photosynthesis and respiration, and CH4 flux with climate-controlled chambers; leaf-level CO2 exchange and biochemistry; substrate-induced respiration, CH4 production and consumption potentials with laboratory incubations; plant species composition and abundance; and microclimate (peat temperature, moisture, light interception). After 15 years, we have found that NEE has decreased, and CH4 emissions have increased, in the highest nutrient treatments owing to changes in vegetation, microtopography, and peat characteristics. Vegetation changes include a loss of Sphagnum moss and introduction of new deciduous species. Simulated atmospheric N deposition has not benefitted the photosynthetic apparatus of the dominant evergreen shrubs, but resulted in higher foliar respiration, contributing to a weaker ecosystem CO2 sink. Loss of moss has led to wetter near-surface substrate, higher rates of decomposition and CH4 emission, and a shift in microbial communities. Thus, elevated atmospheric deposition of nutrients may endanger C storage in peatlands through a complex suite of feedbacks and interactions among vegetation, microclimate, and microbial communities.

  16. Experimental study on the characteristics of ventilated cavitation around an underwater navigating body influenced by turbulent drag-reducing additives

    Science.gov (United States)

    Jiang, ChenXing; Li, FengChen

    2015-09-01

    In this study, a new control strategy for turbulent drag reduction involving ventilated cavitation is proposed. The configurational and hydrodynamic characteristics of ventilated cavities influenced by turbulent drag-reducing additives were experimentally studied in water tunnel. The test model was fixed in the water tunnel by a strut in the aft-part. Aqueous solutions of CTAC/NaSal (cetyltrimethyl ammonium chloride/sodium salicylate) with weight concentrations of 100, 200, 400 and 600 ppm (part per million), respectively, were injected into the ventilated air cavity from the edge of the cavitator with accurate control by an injection pump. The cavity configurations were recorded by a high-speed CCD camera. The hydrodynamic characteristics of the test model were measured by a six-component balance. Experimental results show that, within the presently tested cases, the lengths of cavity influenced by drag-reducing solution are smaller than normal condition (ventilated cavity) in water, but the asymmetry of the cavity is improved. The drag resisted by the test model is reduced dramatically (the maximum drag reduction can reach to 80%) and the re-entrant jet is more complex after the CTAC solution is injected into the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitating asymmetry and further drag reduction.

  17. Fast detection of nutrient limitation in macroalgae and seagrass with nutrient-induced fluorescence.

    Directory of Open Access Journals (Sweden)

    Joost den Haan

    Full Text Available Rapid determination of which nutrients limit the primary production of macroalgae and seagrasses is vital for understanding the impacts of eutrophication on marine and freshwater ecosystems. However, current methods to assess nutrient limitation are often cumbersome and time consuming. For phytoplankton, a rapid method has been described based on short-term changes in chlorophyll fluorescence upon nutrient addition, also known as Nutrient-Induced Fluorescence Transients (NIFTs. Thus far, though, the NIFT technique was not well suited for macroalgae and seagrasses.We developed a new experimental setup so that the NIFT technique can be used to assess nutrient limitation of benthic macroalgae and seagrasses. We first tested the applicability of the technique on sea lettuce (Ulva lactuca cultured in the laboratory on nutrient-enriched medium without either nitrogen or phosphorus. Addition of the limiting nutrient resulted in a characteristic change in the fluorescence signal, whereas addition of non-limiting nutrients did not yield a response. Next, we applied the NIFT technique to field samples of the encrusting fan-leaf alga Lobophora variegata, one of the key algal species often involved in the degradation of coral reef ecosystems. The results pointed at co-limitation of L. variegata by phosphorus and nitrogen, although it responded more strongly to phosphate than to nitrate and ammonium addition. For turtle grass (Thalassia testudinum we found the opposite result, with a stronger NIFT response to nitrate and ammonium than to phosphate.Our extension of the NIFT technique offers an easy and fast method (30-60 min per sample to determine nutrient limitation of macroalgae and seagrasses. We successfully applied this technique to macroalgae on coral reef ecosystems and to seagrass in a tropical inner bay, and foresee wider application to other aquatic plants, and to other marine and freshwater ecosystems.

  18. Composting system for waste treatment coca leaf with the addition of three biological activators in the Experimental Center Kallutaca

    Directory of Open Access Journals (Sweden)

    Apaza-Condori Emma Eva

    2015-11-01

    Full Text Available The objective of this study was to evaluate the composting process waste coca leaf with the addition of three biological activators (yogurt, whey and yeast. This work was carried out Kallutaca Experimental Center, Biofertilizers module Career Agricultural Engineering at the Public University of El Alto, La Paz municipality of Laja. Posed treatments were: T1 (+ Yogurt Coca wastes; T2 (Coca wastes + whey; T3 (Coca wastes + yeast and T4 (Control. The design was completely randomized with 4 treatments and 3 repetitions. The values in N are classified medium and high levels the quantities of P, K are classified as middle levels. The value obtained 7.9 pH, EC 12950 µS/cm and 61% organic matter belong to treatment T1. The decomposition time was a period of 105 days corresponds to treatment T3.

  19. Numerical and Experimental Study of Ti6Al4V Components Manufactured Using Powder Bed Fusion Additive Manufacturing

    Science.gov (United States)

    Zielinski, Jonas; Mindt, Hans-Wilfried; Düchting, Jan; Schleifenbaum, Johannes Henrich; Megahed, Mustafa

    2017-12-01

    Powder bed fusion additive manufacturing of titanium alloys is an interesting manufacturing route for many applications requiring high material strength combined with geometric complexity. Managing powder bed fusion challenges, including porosity, surface finish, distortions and residual stresses of as-built material, is the key to bringing the advantages of this process to production main stream. This paper discusses the application of experimental and numerical analysis towards optimizing the manufacturing process of a demonstration component. Powder characterization including assessment of the reusability, assessment of material consolidation and process window optimization is pursued prior to applying the identified optima to study the distortion and residual stresses of the demonstrator. Comparisons of numerical predictions with measurements show good correlations along the complete numerical chain.

  20. Effects of anabolic and catabolic nutrients on woody plant encroachment after long-term experimental fertilization in a South African savanna.

    Science.gov (United States)

    Mills, Anthony J; Milewski, Antoni V; Snyman, Dirk; Jordaan, Jorrie J

    2017-01-01

    The causes of the worldwide problem of encroachment of woody plants into grassy vegetation are elusive. The effects of soil nutrients on competition between herbaceous and woody plants in various landscapes are particularly poorly understood. A long-term experiment of 60 plots in a South African savanna, comprising annual applications of ammonium sulphate (146-1166 kg ha-1 yr-1) and superphosphate (233-466 kg ha-1 yr-1) over three decades, and subsequent passive protection over another three decades, during which indigenous trees encroached on different plots to extremely variable degrees, provided an opportunity to investigate relationships between soil properties and woody encroachment. All topsoils were analysed for pH, acidity, EC, water-dispersible clay, Na, Mg, K, Ca, P, S, C, N, NH4, NO3, B, Mn, Cu and Zn. Applications of ammonium sulphate (AS), but not superphosphate (SP), greatly constrained tree abundance relative to control plots. Differences between control plots and plots that had received maximal AS application were particularly marked (16.3 ± 5.7 versus 1.2 ± 0.8 trees per plot). Soil properties most affected by AS applications included pH (H2O) (control to maximal AS application: 6.4 ± 0.1 to 5.1 ± 0.2), pH (KCl) (5.5 ± 0.2 to 4.0 ± 0.1), acidity (0.7 ± 0.1 to 2.6 ± 0.3 cmol kg-1), acid saturation (8 ± 2 to 40 ± 5%), Mg (386 ± 25 to 143 ± 15 mg kg-1), Ca (1022 ± 180 to 322 ± 14 mg kg-1), Mn (314 ± 11 to 118 ± 9 mg kg-1), Cu (3.6 ± 0.3 to 2.3 ± 0.2 mg kg-1) and Zn (6.6 ± 0.4 to 3.7 ± 0.4 mg kg-1). Magnesium, B, Mn and Cu were identified using principal component analysis, boundary line analysis and Kruskal-Wallis rank sum tests as the nutrients most likely to be affecting tree abundance. The ratio Mn/Cu was most related to tree abundance across the experiment, supporting the hypothesis that competition between herbaceous and woody plants depends on the availability of anabolic relative to catabolic nutrients. These findings, based

  1. A combined experimental and in silico characterization to highlight additional structural features and properties of a potentially new drug

    Science.gov (United States)

    Bastos, Isadora T. S.; Costa, Fanny N.; Silva, Tiago F.; Barreiro, Eliezer J.; Lima, Lídia M.; Braz, Delson; Lombardo, Giuseppe M.; Punzo, Francesco; Ferreira, Fabio F.; Barroso, Regina C.

    2017-10-01

    LASSBio-1755 is a new cycloalkyl-N-acylhydrazone parent compound designed for the development of derivatives with antinociceptive and anti-inflammatory activities. Although single crystal X-ray diffraction has been considered as the golden standard in structure determination, we successfully used X-ray powder diffraction data in the structural determination of new synthesized compounds, in order to overcome the bottle-neck due to the difficulties experienced in harvesting good quality single crystals of the compounds. We therefore unequivocally assigned the relative configuration (E) to the imine double bond and a s-cis conformation of the amide function of the N-acylhydrazone compound. These features are confirmed by a computational analysis performed on the basis of molecular dynamics calculations, which are extended not only to the structural characteristics but also to the analysis of the anisotropic atomic displacement parameters, a further information - missed in a typical powder diffraction analysis. The so inferred data were used to perform additional cycles of refinement and eventually generate a new cif file with additional physical information. Furthermore, crystal morphology prediction was performed, which is in agreement with the experimental images acquired by scanning electron microscopy, thus providing useful information on possible alternative paths for better crystallization strategies.

  2. Bond Strength of Experimental Low-viscosity Resin Materials to Early Enamel Caries Lesions: Effect of Diluent/Solvent Addition.

    Science.gov (United States)

    Araújo, Tatiany Gabrielle Freire; Sfalcin, Ravana Angelini; de Araújo, Giovana Spagnolo Albamonte; Alonso, Roberta Caroline Brusch; Puppin-Rontani, Regina Maria

    2015-04-01

    To evaluate the effect of different concentrations of monomers and solvents/diluents on the microtensile bond strength (μTBS) bond strength of experimental low-viscosity resins (infiltrants) to enamel caries-like lesions (ECLL). Flat enamel blocks obtained from sound human third molars were submitted to ECLL formation and randomly distributed into 9 groups (n = 10): G1: TEG-DMA 100%; G2: TEG-DMA 80%, ethanol 20%; G3; TEG-DMA 80%, HEMA 20%; G4: TEG-DMA 75%, UDMA 25%; G5: TEG-DMA 60%, UDMA 20%, ethanol 20%; G6: TEG-DMA 60%, UDMA 20%, HEMA 20%; G7: TEG-DMA 75%, bis-EMA 25%; G8: TEG-DMA 60%, bis-EMA 20%, ethanol 20%; G9: TEG-DMA 60%, bis-EMA 20%, HEMA 20%. After etching with 37% phosphoric acid for 60 s, experimental infiltrants were actively applied and photocured for 60 s, then stored in 100% humidity (24 h, 37°C). Hourglass-shaped specimens were obtained and the μTBS test performed (MPa). The fracture patterns were assessed by SEM. Data were submitted to two way-ANOVA and Tukey's tests (α = 0.05). The highest μTBS value was observed for G4 (TEG-DMA/UDMA, 19.18 MPa) and the lowest for G5 (TEG-DMA/UDMA/ethanol, 9.00 MPa). A significant decrease in μTBS was observed for all groups containing ethanol (G2, G5, and G8). The addition of HEMA did not affect μTBS values. Most groups showed a high frequency of mixed failure between infiltrant and enamel. The addition of bis-EMA or UDMA to TEG-DMA-based infiltrants did not improve bond strength to carious enamel. The ethanol addition negatively affected the bonding strength of infiltrants to enamel caries-like lesions, regardless of the resin matrix composition of the infiltrant.

  3. The effect of sucrose application frequency and basal nutrient conditions on the calcium and phosphate content of experimental dental plaque.

    Science.gov (United States)

    Pearce, E I F; Sissons, C H; Coleman, M; Wang, X; Anderson, S A; Wong, L

    2002-01-01

    A reduced pool of calcium in dental plaque would be expected to increase the ability of plaque fluid to dissolve the underlying enamel when the pH falls during sugar exposure. We have examined the relationship between frequency of sugar application and Ca and P(i) concentrations in artificial mouth plaque microcosm biofilms. Ten plaques were grown simultaneously from a human saliva inoculum using a continuous flow of simulated saliva, DMM, supplemented with either urea or glucose to modulate the resting pH. In addition the plaques received sucrose applications of varying frequency: 12-, 8-, 6-, or 4-hourly, or not at all. After 15 days the plaques were sampled by taking 4 full-thickness specimens of each, and acid-extractable Ca and P(i), and alkali-soluble protein and carbohydrate were determined. Ca and P(i) concentrations were in a range comparable with those in human plaque, except in the DMM + urea plaque receiving no sucrose, when concentrations were higher. Plaque Ca concentration decreased significantly as sucrose application frequency increased. Increasing sucrose application frequency also reduced the protein, i.e. the cell biomass, content of the plaques and, in the case of DMM + urea plaques, increased the water-insoluble hexose content, presumably extracellular polysaccharide. Reduced biomass was partly due to the bulking of plaque with extracellular polysaccharide, but the marked effect of urea on polysaccharide formation is not understood. This study shows that increasing frequency of sugar application alters dental plaque by reducing its mineral protection capacity. Copyright 2002 S. Karger AG, Basel

  4. The impact of food and nutrient-based standards on primary school children's lunch and total dietary intake: a natural experimental evaluation of government policy in England.

    Directory of Open Access Journals (Sweden)

    Suzanne Spence

    Full Text Available In 2005, the nutritional content of children's school lunches in England was widely criticised, leading to a major policy change in 2006. Food and nutrient-based standards were reintroduced requiring primary schools to comply by September 2008. We aimed to determine the effect of the policy on the nutritional content at lunchtime and in children's total diet. We undertook a natural experimental evaluation, analysing data from cross-sectional surveys in 12 primary schools in North East England, pre and post policy. Dietary data were collected on four consecutive days from children aged 4-7 years (n = 385 in 2003-4; n = 632 in 2008-9. We used linear mixed effect models to analyse the effects of gender, year, and lunch type on children's mean total daily intake. Both pre- and post-implementation, children who ate a school lunch consumed less sodium (mean change -128 mg, 95% CI: -183 to -73 mg in their total diet than children eating home-packed lunches. Post-implementation, children eating school lunches consumed a lower % energy from fat (-1.8%, -2.8 to -0.9 and saturated fat (-1.0%; -1.6 to -0.5 than children eating packed lunches. Children eating school lunches post implementation consumed significantly more carbohydrate (16.4 g, 5.3 to 27.6, protein (3.6 g, 1.1 to 6.0, non-starch polysaccharides (1.5 g, 0.5 to 1.9, vitamin C (0.7 mg, 0.6 to 0.8, and folate (12.3 µg, 9.7 to 20.4 in their total diet than children eating packed lunches. Implementation of school food policy standards was associated with significant improvements in the nutritional content of school lunches; this was reflected in children's total diet. School food- and nutrient-based standards can play an important role in promoting dietary health and may contribute to tackling childhood obesity. Similar policy measures should be considered for other environments influencing children's diet.

  5. The impact of food and nutrient-based standards on primary school children's lunch and total dietary intake: a natural experimental evaluation of government policy in England.

    Science.gov (United States)

    Spence, Suzanne; Delve, Jennifer; Stamp, Elaine; Matthews, John N S; White, Martin; Adamson, Ashley J

    2013-01-01

    In 2005, the nutritional content of children's school lunches in England was widely criticised, leading to a major policy change in 2006. Food and nutrient-based standards were reintroduced requiring primary schools to comply by September 2008. We aimed to determine the effect of the policy on the nutritional content at lunchtime and in children's total diet. We undertook a natural experimental evaluation, analysing data from cross-sectional surveys in 12 primary schools in North East England, pre and post policy. Dietary data were collected on four consecutive days from children aged 4-7 years (n = 385 in 2003-4; n = 632 in 2008-9). We used linear mixed effect models to analyse the effects of gender, year, and lunch type on children's mean total daily intake. Both pre- and post-implementation, children who ate a school lunch consumed less sodium (mean change -128 mg, 95% CI: -183 to -73 mg) in their total diet than children eating home-packed lunches. Post-implementation, children eating school lunches consumed a lower % energy from fat (-1.8%, -2.8 to -0.9) and saturated fat (-1.0%; -1.6 to -0.5) than children eating packed lunches. Children eating school lunches post implementation consumed significantly more carbohydrate (16.4 g, 5.3 to 27.6), protein (3.6 g, 1.1 to 6.0), non-starch polysaccharides (1.5 g, 0.5 to 1.9), vitamin C (0.7 mg, 0.6 to 0.8), and folate (12.3 µg, 9.7 to 20.4) in their total diet than children eating packed lunches. Implementation of school food policy standards was associated with significant improvements in the nutritional content of school lunches; this was reflected in children's total diet. School food- and nutrient-based standards can play an important role in promoting dietary health and may contribute to tackling childhood obesity. Similar policy measures should be considered for other environments influencing children's diet.

  6. Cognitive dysfunction is sustained after rescue therapy in experimental cerebral malaria, and is reduced by additive antioxidant therapy.

    Science.gov (United States)

    Reis, Patricia A; Comim, Clarissa M; Hermani, Fernanda; Silva, Bruno; Barichello, Tatiana; Portella, Aline C; Gomes, Flavia C A; Sab, Ive M; Frutuoso, Valber S; Oliveira, Marcus F; Bozza, Patricia T; Bozza, Fernando A; Dal-Pizzol, Felipe; Zimmerman, Guy A; Quevedo, João; Castro-Faria-Neto, Hugo C

    2010-06-24

    Neurological impairments are frequently detected in children surviving cerebral malaria (CM), the most severe neurological complication of infection with Plasmodium falciparum. The pathophysiology and therapy of long lasting cognitive deficits in malaria patients after treatment of the parasitic disease is a critical area of investigation. In the present study we used several models of experimental malaria with differential features to investigate persistent cognitive damage after rescue treatment. Infection of C57BL/6 and Swiss (SW) mice with Plasmodium berghei ANKA (PbA) or a lethal strain of Plasmodium yoelii XL (PyXL), respectively, resulted in documented CM and sustained persistent cognitive damage detected by a battery of behavioral tests after cure of the acute parasitic disease with chloroquine therapy. Strikingly, cognitive impairment was still present 30 days after the initial infection. In contrast, BALB/c mice infected with PbA, C57BL6 infected with Plasmodium chabaudi chabaudi and SW infected with non lethal Plasmodium yoelii NXL (PyNXL) did not develop signs of CM, were cured of the acute parasitic infection by chloroquine, and showed no persistent cognitive impairment. Reactive oxygen species have been reported to mediate neurological injury in CM. Increased production of malondialdehyde (MDA) and conjugated dienes was detected in the brains of PbA-infected C57BL/6 mice with CM, indicating high oxidative stress. Treatment of PbA-infected C57BL/6 mice with additive antioxidants together with chloroquine at the first signs of CM prevented the development of persistent cognitive damage. These studies provide new insights into the natural history of cognitive dysfunction after rescue therapy for CM that may have clinical relevance, and may also be relevant to cerebral sequelae of sepsis and other disorders.

  7. Cognitive dysfunction is sustained after rescue therapy in experimental cerebral malaria, and is reduced by additive antioxidant therapy.

    Directory of Open Access Journals (Sweden)

    Patricia A Reis

    2010-06-01

    Full Text Available Neurological impairments are frequently detected in children surviving cerebral malaria (CM, the most severe neurological complication of infection with Plasmodium falciparum. The pathophysiology and therapy of long lasting cognitive deficits in malaria patients after treatment of the parasitic disease is a critical area of investigation. In the present study we used several models of experimental malaria with differential features to investigate persistent cognitive damage after rescue treatment. Infection of C57BL/6 and Swiss (SW mice with Plasmodium berghei ANKA (PbA or a lethal strain of Plasmodium yoelii XL (PyXL, respectively, resulted in documented CM and sustained persistent cognitive damage detected by a battery of behavioral tests after cure of the acute parasitic disease with chloroquine therapy. Strikingly, cognitive impairment was still present 30 days after the initial infection. In contrast, BALB/c mice infected with PbA, C57BL6 infected with Plasmodium chabaudi chabaudi and SW infected with non lethal Plasmodium yoelii NXL (PyNXL did not develop signs of CM, were cured of the acute parasitic infection by chloroquine, and showed no persistent cognitive impairment. Reactive oxygen species have been reported to mediate neurological injury in CM. Increased production of malondialdehyde (MDA and conjugated dienes was detected in the brains of PbA-infected C57BL/6 mice with CM, indicating high oxidative stress. Treatment of PbA-infected C57BL/6 mice with additive antioxidants together with chloroquine at the first signs of CM prevented the development of persistent cognitive damage. These studies provide new insights into the natural history of cognitive dysfunction after rescue therapy for CM that may have clinical relevance, and may also be relevant to cerebral sequelae of sepsis and other disorders.

  8. Nutrient Loading Fosters Seagrass Productivity Under Ocean Acidification.

    Science.gov (United States)

    Ravaglioli, Chiara; Lauritano, Chiara; Buia, Maria Cristina; Balestri, Elena; Capocchi, Antonella; Fontanini, Debora; Pardi, Giuseppina; Tamburello, Laura; Procaccini, Gabriele; Bulleri, Fabio

    2017-10-23

    The effects of climate change are likely to be dependent on local settings. Nonetheless, the compounded effects of global and regional stressors remain poorly understood. Here, we used CO2 vents to assess how the effects of ocean acidification on the seagrass, Posidonia oceanica, and the associated epiphytic community can be modified by enhanced nutrient loading. P. oceanica at ambient and low pH sites was exposed to three nutrient levels for 16 months. The response of P. oceanica to experimental conditions was assessed by combining analyses of gene expression, plant growth, photosynthetic pigments and epiphyte loading. At low pH, nutrient addition fostered plant growth and the synthesis of photosynthetic pigments. Overexpression of nitrogen transporter genes following nutrient additions at low pH suggests enhanced nutrient uptake by the plant. In addition, enhanced nutrient levels reduced the expression of selected antioxidant genes in plants exposed to low pH and increased epiphyte cover at both ambient and low pH. Our results show that the effects of ocean acidification on P. oceanica depend upon local nutrient concentration. More generally, our findings suggest that taking into account local environmental settings will be crucial to advance our understanding of the effects of global stressors on marine systems.

  9. Effects of dietary addition of cellulase and a Saccharomyces cerevisiae fermentation product on nutrient digestibility, rumen fermentation and enteric methane emissions in growing goats.

    Science.gov (United States)

    Lu, Qi; Wu, Jian; Wang, Min; Zhou, Chuanshe; Han, Xuefeng; Odongo, Edwin Nicholas; Tan, Zhiliang; Tang, Shaoxun

    2016-01-01

    This study was designed to assess the effectiveness of dietary cellulase (243 U/g, derived from Neocallimastix patriciarum) and a Saccharomyces cerevisiae fermentation product (yeast product) on ruminal fermentation characteristics, enteric methane (CH4) emissions and methanogenic community in growing goats. The experiment was conducted in a 5 × 5 Latin square design using five Xiangdong black wether goats. The treatments included a Control and two levels of cellulase (0.8 g and 1.6 g/kg dry matter intake (DMI), i.e. 194 U/kg and 389 U/kg DMI, respectively) crossed over with two levels (6 g or 12 g/kg DMI) of the yeast product. There were no significant differences regarding feed intake, apparent digestibility of organic matter, neutral detergent fibre and acid detergent fibre among all the treatments. In comparison with the Control, the ruminal ammonia N concentration was decreased (p = 0.001) by cellulase and yeast product addition. The activities of carboxymethylcellulase and xylanase were decreased after cellulase addition. Moreover, dietary cellulase and yeast product addition led to a significant reduction (p < 0.05) of enteric CH4 emissions although the diversity and copy numbers of methanogens among treatments were not dissimilar. The present results indicate that the combination of cellulase and yeast fermentation product can reduce the production of CH4 energy and mitigate the enteric CH4 emissions to a certain degree.

  10. Experimental and numerical studies of the effects of hydrogen addition on the structure of a laminar methane-nitrogen jet in hot coflow under MILD conditions

    NARCIS (Netherlands)

    Sepman, Alexey; Abtahizadeh, Ebrahim; Mokhov, Anatoli; van Oijen, Jeroen; Levinsky, Howard; de Goey, Philip

    2013-01-01

    In this work we investigate the effects of hydrogen addition on the flame structure of MILD combustion both experimentally and numerically using a laminar-jet-in-hot-coflow (LJHC) geometry. The addition of hydrogen appreciably decreases the flame height (similar to 25%), however only modestly

  11. Long-term experimental warming, shading and nutrient addition affect the concentration of phenolic compounds in arctic-alpine deciduous and evergreen dwarf shrubs

    DEFF Research Database (Denmark)

    Hansen, Anja Hoff; Jonasson, Sven Evert; Michelsen, Anders

    2006-01-01

    -arctic, alpine ecosystem, we investigated the effects on carbon based secondary compounds (CBSC) and nitrogen in one dominant deciduous dwarf shrub, Salix herbacea × polaris and two dominant evergreen dwarf shrubs, Cassiope tetragona and Vaccinium vitis-idaea throughout one growing season. The main aims were....... herbacea × polaris than in the corresponding current year's leaf cohort of the evergreen C. tetragona. The changes were also much higher than in the 1-year-old leaves of the two evergreens probably due to differences in dilution and turnover of CBSC in growing and mature leaves paired with different rates...

  12. Nutrient Limitation in Central Red Sea Mangroves

    KAUST Repository

    Almahasheer, Hanan

    2016-12-24

    As coastal plants that can survive in salt water, mangroves play an essential role in large marine ecosystems (LMEs). The Red Sea, where the growth of mangroves is stunted, is one of the least studied LMEs in the world. Mangroves along the Central Red Sea have characteristic heights of ~2 m, suggesting nutrient limitation. We assessed the nutrient status of mangrove stands in the Central Red Sea and conducted a fertilization experiment (N, P and Fe and various combinations thereof) on 4-week-old seedlings of Avicennia marina to identify limiting nutrients and stoichiometric effects. We measured height, number of leaves, number of nodes and root development at different time periods as well as the leaf content of C, N, P, Fe, and Chl a in the experimental seedlings. Height, number of nodes and number of leaves differed significantly among treatments. Iron treatment resulted in significantly taller plants compared with other nutrients, demonstrating that iron is the primary limiting nutrient in the tested mangrove population and confirming Liebig\\'s law of the minimum: iron addition alone yielded results comparable to those using complete fertilizer. This result is consistent with the biogenic nature of the sediments in the Red Sea, which are dominated by carbonates, and the lack of riverine sources of iron.

  13. Experimental investigation of the effect of titanium dioxide and barium titanate additives on DC transient currents in low density polyethylene

    DEFF Research Database (Denmark)

    Khalil, M.S; Henk, Peter O; Henriksen, Mogens

    1988-01-01

    The effect of titanium dioxide as a semiconductive additive and barium titanate as a highly polar additive on the DC transient currents in low-density polyethylene is investigated. Experiments were made using thick specimens under a high electric field (>25×106 V/m) and a constant temperature of 40...

  14. Assessing Soil Nutrient Additions through Different Composting ...

    African Journals Online (AJOL)

    Bheema

    Four compost types (vermi-compost, conventional compost, farmers' compost and community nursery compost) with three replications were used in this study. ..... Edwards, C.A. 1998. The use of earthworm in the break down and management of organic wastes. In: C.A. Edwards (ed.) Earthworm Ecology. St. Lucie Press ...

  15. Assessing Soil Nutrient Additions through Different Composting ...

    African Journals Online (AJOL)

    The use of vermi-compost in northern Ethiopia is not a common practice. It is, therefore, important to understand the possible impediments through studying its chemical and biological properties and its extra contribution compared to other composting techniques. Four compost types (vermi-compost, conventional compost, ...

  16. Nutrients - Elwha River salmon carcass addition experiment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Dam removal and other fish-barrier removal projects in western North America are assumed to boost freshwater productivity via the transport of marine-derived...

  17. Key Nutrients.

    Science.gov (United States)

    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…

  18. The effects of leaf litter nutrient pulses on Alliaria petiolata performance

    Directory of Open Access Journals (Sweden)

    Robert W. Heckman

    2015-08-01

    Full Text Available Nutrient pulses can facilitate species establishment and spread in new habitats, particularly when one species more effectively uses that nutrient pulse. Biological differences in nutrient acquisition between native and exotic species may facilitate invasions into a variety of habitats including deciduous forest understories. Alliaria petiolata (Bieb. Cavara & Grande is an important invader of deciduous forest understories throughout much of North America. These understory communities contain many species which perform the majority of their growth and reproduction before canopy closure in spring. Because A. petiolata is a wintergreen biennial that can be active during autumn and winter, it may utilize nutrients released from decaying leaf litter before its competitors. To investigate this we manipulated the timing of leaf litter addition (fall or spring and experimentally simulated the nutrient pulse from decaying leaves using artificial fertilizer. To determine whether A. petiolata affected the abundance of understory competitors, we also removed A. petiolata from one treatment. A. petiolata that received early nutrients exhibited greater growth. Treatments receiving fall leaf litter or artificial nutrients had greater A. petiolata adult biomass than plots receiving spring nutrient additions (leaf litter or artificial nutrients. However, fall leaf litter addition had no effect on the richness of competitor species. Thus, wintergreen phenology may contribute to the spread of A. petiolata through deciduous forest understories, but may not explain community-level impacts of A. petiolata in deciduous forests.

  19. Experimental and Modeling Investigation of the Effectof H2S Addition to Methane on the Ignition and Oxidation at High Pressures

    DEFF Research Database (Denmark)

    Gersen, Sander; van Essen, Martijn; Darmeveil, Harry

    2017-01-01

    The autoignition and oxidation behavior of CH4/H2S mixtures has been studied experimentally in a rapid compression machine (RCM) and a high-pressure flow reactor. The RCM measurements show that the addition of 1% H2S to methane reduces the autoignition delay time by a factor of 2 at pressures ran...... of organosulfuric compounds....

  20. Patrones de lluvia, transcolación y flujo de nutrientes en las cuencas de Bisley, Bosque Experimental de Luquillo, Puerto Rico

    Science.gov (United States)

    Tamara Heartsill; Carlos R. Estrada Ruiz; Samuel Moya

    2006-01-01

    Describimos la cantidad de lluvia y transcolación durante veinte años (1988-2008), incluyendo varios periodos de sequías, huracanes y lluvias intensas. La composición de nutrientes en la lluvia y transcolación fueron medidos semanalmente durante quince años (1988-2002), incluyendo los periodos de...

  1. Managing Soil Biota-Mediated Decomposition and Nutrient Mineralization in Sustainable Agroecosystems

    Directory of Open Access Journals (Sweden)

    Joann K. Whalen

    2014-01-01

    Full Text Available Transformation of organic residues into plant-available nutrients occurs through decomposition and mineralization and is mediated by saprophytic microorganisms and fauna. Of particular interest is the recycling of the essential plant elements—N, P, and S—contained in organic residues. If organic residues can supply sufficient nutrients during crop growth, a reduction in fertilizer use is possible. The challenge is synchronizing nutrient release from organic residues with crop nutrient demands throughout the growing season. This paper presents a conceptual model describing the pattern of nutrient release from organic residues in relation to crop nutrient uptake. Next, it explores experimental approaches to measure the physical, chemical, and biological barriers to decomposition and nutrient mineralization. Methods are proposed to determine the rates of decomposition and nutrient release from organic residues. Practically, this information can be used by agricultural producers to determine if plant-available nutrient supply is sufficient to meet crop demands at key growth stages or whether additional fertilizer is needed. Finally, agronomic practices that control the rate of soil biota-mediated decomposition and mineralization, as well as those that facilitate uptake of plant-available nutrients, are identified. Increasing reliance on soil biological activity could benefit crop nutrition and health in sustainable agroecosystems.

  2. Experimental analysis on semi-finishing machining of Ti6Al4V additively manufactured by direct melting laser sintering

    Science.gov (United States)

    Imbrogno, Stano; Bordin, Alberto; Bruschi, Stefania; Umbrello, Domenico

    2016-10-01

    The Additive Manufacturing (AM) techniques are particularly appealing especially for titanium aerospace and biomedical components because they permit to achieve a strong reduction of the buy-to-fly ratio. However, finishing machining operations are often necessary to reduce the uneven surface roughness and geometrics because of local missing accuracy. This work shows the influence of the cutting parameters, cutting speed and feed rate, on the cutting forces as well as on the thermal field observed in the cutting zone, during a turning operation carried out on bars made of Ti6Al4V obtained by the AM process called Direct Metal Laser Sintering (DMLS). Moreover, the sub-surface microstructure alterations due to the process are also showed and commented.

  3. Effects of agricultural subsidies of nutrients and detritus on fish and plankton of shallow-reservoir ecosystems.

    Science.gov (United States)

    Pilati, Alberto; Vanni, Michael J; González, María J; Gaulke, Alicia K

    2009-06-01

    Agricultural activities increase exports of nutrients and sediments to lakes, with multiple potential impacts on recipient ecosystems. Nutrient inputs enhance phytoplankton and upper trophic levels, and sediment inputs can shade phytoplankton, interfere with feeding of consumers, and degrade benthic habitats. Allochthonous sediments are also a potential food source for detritivores, as is sedimenting autochthonous phytodetritus, the production of which is stimulated by nutrient inputs. We examined effects of allochthonous nutrient and sediment subsidies on fish and plankton, with special emphasis on gizzard shad (Dorosoma cepedianum). This widespread and abundant omnivorous fish has many impacts on reservoir ecosystems, including negative effects on water quality via nutrient cycling and on fisheries via competition with sportfish. Gizzard shad are most abundant in agriculturally impacted, eutrophic systems; thus, agricultural subsidies may affect reservoir food webs directly and by enhancing gizzard shad biomass. We simulated agricultural subsidies of nutrients and sediment detritus by manipulating dissolved nutrients and allochthonous detritus in a 2 x 2 factorial design in experimental ponds. Addition of nutrients alone increased primary production and biomass of zooplanktivorous fish (bluegill and young-of-year gizzard shad). Addition of allochthonous sediments alone increased algal sedimentation and decreased seston and sediment C:P ratios. Ponds receiving both nutrients and sediments showed highest levels of phytoplankton and total phosphorus. Adult and juvenile gizzard shad biomass was enhanced equally by nutrient or sediment addition, probably because this apparently P-limited detritivore ingested similar amounts of P in all subsidy treatments. Nutrient excretion rates of gizzard shad were higher in ponds with nutrient additions, where sediments were composed mainly of phytodetritus. Therefore, gizzard shad can magnify the direct effects of nutrient

  4. [Temporal and spatial variation of water nutrient level after exogenous nutrient input].

    Science.gov (United States)

    Fu, Ling; Zhao, Kai; Wang, Guo-Xiang; Ou, Yuan; Fan, Zhou; Mao, Li-Na; Zhang, Jia; Han, Rui-Ming

    2014-04-01

    In order to study the spatial and temporal variations of nitrogen (N) and phosphorous (P) nutrition in artificial wetlands after a single exogenous nutrient input, 6 mosaic communities of 7 plant species were set up in a cement channel in the greenhouse. After the addition of N and P nutritional solutions, the concentrations of dissolved total nitrogen (DTN), dissolved total phosphorous (DTP), ammonia nitrogen (NH4(+)-N), nitrate nitrogen (NO3(-) -N) and nitrite nitrogen (NO2(-) -N) in the surface, middle, and bottom layers of the bulk water were determined regularly within 22 days. The results show that: (1) the water depth and measuring date have significant effects on nutritional contents while the type of plant communities have no such an influence; (2) the diffusion of nutrient from surface to the middle water layers is relatively slow, which costs 6 days under the current experimental condition; (3) in the bottom water layer, nutritional concentrations had no significant changes except for NO2-N, thus the exogenous nutrient input mainly affects the nutrient contents of surface and middle-level bulk water; (4) DTP and NH4(+) -N contents gradually decline to similar levels that before the nutritional input event until the end of experimental period, though DTN and NO3(-) -N content decrease much more slowly; (5) the fact that NO2(-) -N contents rise in water layers of all depths demonstrates that nitrification and denitrification in the process of N circulation are enhanced. It is concluded that exogenous nutrient inputs not only harm aquatic ecosystems but also directly threat human health.

  5. Guanosine 5'-monophosphate-chelated calcium and iron feed additives maintains egg production and prevents Salmonella Gallinarum in experimentally infected layers.

    Science.gov (United States)

    Noh, Hye-Ji; Kim, HeeKyong; Heo, Su Jeong; Cho, Hyang Hyun; Koh, Hong Bum

    2017-09-30

    We evaluated the effects of guanosine 5'-monophosphate (GMP)-chelated calcium and iron (CaFe-GMP) on health and egg quality in layers experimentally infected with Salmonella Gallinarum. In this study, a CaFe-GMP feed additive was added to a commercial layer feed and fed to layers over a four-week period. All were inoculated with Salmonella Gallinarum. Body weight, mortality, clinical symptoms, and poultry production including feed intake, egg production, egg loss, and feed conversion rate were observed, and Salmonella Gallinarum was re-isolated from the liver, spleen, and cecum of the layers. All tested internal organs for the CaFe-GMP additive group exhibited significantly lower re-isolation numbers of Salmonella Gallinarum and less severe pathological changes than those in the control group, indicating that the CaFe-GMP feed supplement induced bacterial clearance and increased resistance to Salmonella Gallinarum. Additionally, due to the inhibitory action of CaFe-GMP on the growth of Salmonella Gallinarum, the CaFe-GMP additive group exhibited better egg production, including a higher laying rate and fewer broken eggs. The results suggest that a 0.16% CaFe-GMP additive may help prevent salmonellosis in the poultry industry.

  6. Guanosine 5′-monophosphate-chelated calcium and iron feed additives maintains egg production and prevents Salmonella Gallinarum in experimentally infected layers

    Science.gov (United States)

    Noh, Hye-Ji; Kim, HeeKyong; Heo, Su Jeong; Cho, Hyang Hyun

    2017-01-01

    We evaluated the effects of guanosine 5′-monophosphate (GMP)-chelated calcium and iron (CaFe-GMP) on health and egg quality in layers experimentally infected with Salmonella Gallinarum. In this study, a CaFe-GMP feed additive was added to a commercial layer feed and fed to layers over a four-week period. All were inoculated with Salmonella Gallinarum. Body weight, mortality, clinical symptoms, and poultry production including feed intake, egg production, egg loss, and feed conversion rate were observed, and Salmonella Gallinarum was re-isolated from the liver, spleen, and cecum of the layers. All tested internal organs for the CaFe-GMP additive group exhibited significantly lower re-isolation numbers of Salmonella Gallinarum and less severe pathological changes than those in the control group, indicating that the CaFe-GMP feed supplement induced bacterial clearance and increased resistance to Salmonella Gallinarum. Additionally, due to the inhibitory action of CaFe-GMP on the growth of Salmonella Gallinarum, the CaFe-GMP additive group exhibited better egg production, including a higher laying rate and fewer broken eggs. The results suggest that a 0.16% CaFe-GMP additive may help prevent salmonellosis in the poultry industry. PMID:28057911

  7. Guanosine 5′-monophosphate-chelated calcium and iron feed additives maintains egg production and prevents Salmonella Gallinarum in experimentally infected layers

    OpenAIRE

    Noh, Hye-Ji; Kim, Heekyong; Heo, Su Jeong; Cho, Hyang Hyun; Koh, Hong Bum

    2017-01-01

    We evaluated the effects of guanosine 5′-monophosphate (GMP)-chelated calcium and iron (CaFe-GMP) on health and egg quality in layers experimentally infected with Salmonella Gallinarum. In this study, a CaFe-GMP feed additive was added to a commercial layer feed and fed to layers over a four-week period. All were inoculated with Salmonella Gallinarum. Body weight, mortality, clinical symptoms, and poultry production including feed intake, egg production, egg loss, and feed conversion rate wer...

  8. Experimental and Modeling Investigation of the Effectof H2S Addition to Methane on the Ignition and Oxidation at High Pressures

    OpenAIRE

    Gersen, Sander; van Essen, Martijn; Darmeveil, Harry; Hashemi, Hamid; Rasmussen, Christian Tihic; Christensen, Jakob Munkholt; Glarborg, Peter; Levinsky, Howard

    2017-01-01

    The autoignition and oxidation behavior of CH4/H2S mixtures has been studied experimentally in a rapid compression machine (RCM) and a high-pressure flow reactor. The RCM measurements show that the addition of 1% H2S to methane reduces the autoignition delay time by a factor of 2 at pressures ranging from 30 to 80 bar and temperatures from 930 to 1050 K. The flow reactor experiments performed at 50 bar show that, for stoichiometric conditions,a large fraction of H2S is already consumed at 600...

  9. Nutrient supply of plants in aquaponic systems

    Directory of Open Access Journals (Sweden)

    Andras Bittsanszky

    2016-10-01

    Full Text Available In this preliminary article we present data on plant nutrient concentrations in aquaponics systems, and we compare them to nutrient concentrations in “standard” hydroponic solutions. Our data shows that the nutrient concentrations supplied by the fish in the aquaponics system are significantly lower for most nutrients compared to hydroponic systems. Nevertheless, plants do thrive in solutions that have lower nutrient levels compared to “standard” hydroponic solutions. This is especially true for green leafy vegetables that rarely need additional nutritional supplementation. It is concluded that in the highly complex system of aquaponics, special care has to be taken, via continuous monitoring of the chemical composition of the circulating water, to provide adequate concentrations and ratios of nutrients, and especially for the potentially toxic component, ammonium. If certain plants require nutrient supplementation, we consider that one based on organic substances would be most beneficial. However, protocols for the application of such nutrient amendments still need to be developed.

  10. Nutrient enrichment effect on macroinvertebrates in a lowland stream of Argentina

    Directory of Open Access Journals (Sweden)

    Agustina Cortelezzi

    2015-06-01

    Full Text Available ABSTRACT One of the most important effects derived from the intensive land use is the increase of nutrient concentration in the aquatic systems due to superficial drainage. Besides, the increment of precipitations in South America connected to the global climate change could intensify these anthropic impacts due to the changes in the runoff pattern and a greater discharge of water in the streams and rivers. The pampean streams are singular environments with high natural nutrient concentrations which could be increased even more if the predictions of global climate change for the area are met. In this context, the effect of experimental nutrient addition on macroinvertebrates in a lowland stream is studied. Samplings were carried out from March 2007 to February 2009 in two reaches (fertilized and unfertilized, upstream and downstream from the input of nutrients. The addition of nutrients caused an increase in the phosphorus concentration in the fertilized reach which was not observed for nitrogen concentration. From all macroinvertebrates studied only two taxa had significant differences in their abundance after fertilization: Corbicula fluminea and Ostracoda. Our results reveal that the disturbance caused by the increase of nutrients on the benthic community depends on basal nutrients concentration. The weak response of macroinvertebrates to fertilization in the pampean streams could be due to their tolerance to high concentrations of nutrients in relation to their evolutionary history in streams naturally enriched with nutrients. Further research concerning the thresholds of nutrients affecting macroinvertebrates and about the adaptive advantages of taxa in naturally eutrophic environments is still needed. This information will allow for a better understanding of the processes of nutrient cycling and for the construction of restoration measures in natural eutrophic ecosystems.

  11. Calcium addition at the Hubbard Brook Experimental Forest increases sugar storage, antioxidant activity and cold tolerance in native red spruce (Picea rubens).

    Science.gov (United States)

    Halman, Joshua M; Schaberg, Paul G; Hawley, Gary J; Eagar, Christopher

    2008-06-01

    In fall (November 2005) and winter (February 2006), we collected current-year foliage of native red spruce (Picea rubens Sarg.) growing in a reference watershed and in a watershed treated in 1999 with wollastonite (CaSiO(3), a slow-release calcium source) to simulate preindustrial soil calcium concentrations (Ca-addition watershed) at the Hubbard Brook Experimental Forest (Thornton, NH). We analyzed nutrition, soluble sugar concentrations, ascorbate peroxidase (APX) activity and cold tolerance, to evaluate the basis of recent (2003) differences between watersheds in red spruce foliar winter injury. Foliar Ca and total sugar concentrations were significantly higher in trees in the Ca-addition watershed than in trees in the reference watershed during both fall (P=0.037 and 0.035, respectively) and winter (P=0.055 and 0.036, respectively). The Ca-addition treatment significantly increased foliar fructose and glucose concentrations in November (P=0.013 and 0.007, respectively) and foliar sucrose concentrations in winter (P=0.040). Foliar APX activity was similar in trees in both watersheds during fall (P=0.28), but higher in trees in the Ca-addition watershed during winter (P=0.063). Cold tolerance of foliage was significantly greater in trees in the Ca-addition watershed than in trees in the reference watershed (P<0.001). Our results suggest that low foliar sugar concentrations and APX activity, and reduced cold tolerance in trees in the reference watershed contributed to their high vulnerability to winter injury in 2003. Because the reference watershed reflects forest conditions in the region, the consequences of impaired physiological function caused by soil Ca depletion may have widespread implications for forest health.

  12. Nutrient imbalance in Norway spruce

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar

    2000-11-01

    The studies presented in my thesis indicate that growing Norway spruce in monoculture does not constitute sustainable forest management in a high N and S deposition environment, such as in southern Sweden. The combination of N-induced high growth rates and leaching due to soil acidification causes soil reserves of nutrients to decrease. This will increase the risk of nutrient imbalance within the trees when nutrient demands are not met. The development of nutrient imbalance in Scania, southern Sweden, was shown as negative trends in needle and soil nutrient status from the mid-80s to the present in Norway spruce and Scots pine stands. This imbalance appears to be connected to high levels of N and S deposition. Clear negative effects on tree vitality were found when using a new branch development method. Today, growth and vitality seems to be limited by K, rather than N, in spruce stands older than 40 years. However, younger stands appear to be able to absorb the deposited N without negative effects on growth and vitality. When investigating effects of nutrient stress on tree vitality, indicators such as branch length and shoot multiplication rate, which include effects accumulated over several years, are suitable. Countermeasures are needed in order to maintain the forest production at a high level. Positive effects on tree nutrient status after vitality fertilization (N-free fertilization) was shown in two micronutrient deficient stands in south-central Sweden. In addition, tree vitality was positively affected after the application of a site-adapted fertilizer to the canopy. Site-adaption of fertilizers will most likely improve the possibilities of a positive response on tree growth and vitality in declining stands. In a survey of Norway spruce in mixtures with beech, birch, or oak compared to monocultures it was shown that spruce nutrient status was higher in mixtures with deciduous species than in monocultures. By using mixed-species stands the need for

  13. An evaluation of the effect of sodium bisulfate as a feed additive on Salmonella enterica serotype Enteritidis in experimentally infected broilers.

    Science.gov (United States)

    Kassem, I I; Sanad, Y M; Stonerock, R; Rajashekara, G

    2012-04-01

    The colonization of broiler chickens with Salmonella can pose serious health and economic risks for both consumers and the poultry industry. Because colonization with Salmonella can lead to subsequent contamination of chicken carcasses during processing, preemptive control measures should include the reduction of this pathogen in chickens before slaughter. In this study, we evaluated the effect of sodium bisulfate, a potential antimicrobial feed additive, on Salmonella colonization of experimentally infected broiler chickens. Two hundred and forty 1-d-old chickens were infected orally with Salmonella enterica serotype Enteritidis and divided into 4 groups (each comprised of 60 chickens). Three groups received different concentrations of sodium bisulfate integrated into their feed, while the feed of the fourth group (positive control) was not treated. At time points before the broilers' slaughter age, different organs/tissues (liver, spleen, cecum, and bone marrow) and feces were aseptically collected and tested for the occurrence and density of Salmonella Enteritidis. Our results show that at 3 d postinfection, high colonization with Salmonella Enteritidis was detected and affected all tested tissues and fecal samples. Although colonization decreased across time, Salmonella Enteritidis persisted in the cecum, feces, spleen, and bone marrow, but not in the liver, until slaughter age. Furthermore, the addition of sodium bisulfate to the feed did not significantly reduce Salmonella Enteritidis numbers in infected chickens or affect the shedding of the pathogen.

  14. Experimental manipulation of breakfast in normal and overweight/obese participants is associated with changes to nutrient and energy intake consumption patterns.

    Science.gov (United States)

    Reeves, Sue; Huber, Jörg W; Halsey, Lewis G; Horabady-Farahani, Yasmin; Ijadi, Mehrnaz; Smith, Tina

    2014-06-22

    The effect of breakfast and breakfast omission on daily food intake in normal and overweight participants was investigated. 37 participants were recruited for this experimental study and assigned to one of four groups on the basis of their body mass index (BMI) (normal weight BMI 25 kg/m(2)) and breakfast habits (breakfast eater or breakfast omitter). All participants were requested to eat breakfast for an entire week, and then following a washout period, omit breakfast for an entire week, or vice versa. Seven-day food diaries reporting what was consumed and the timing of consumption were completed for each breakfast condition. Overall more energy was consumed during the breakfast than the no breakfast week. The present study revealed significant effects of timing on energy intakes; more energy was consumed during the afternoon in the no breakfast week compared to the breakfast week. Overweight participants consumed greater amounts of energy than normal weight participants in the early evening. Breakfast omitters consumed more than did breakfast eaters later in the evening. All groups consumed significantly less energy, carbohydrate and fibre in the no breakfast week; however, overweight participants increased their sugar intakes. Consumption of the micronutrients iron and folate was reduced in the no breakfast week. The findings highlight that the timing of food intake and habitual breakfast eating behaviour are important factors when investigating why breakfast consumption may be associated with BMI. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. The Coupling of Solution Chemistry to Plant Nutrient Demand in an on Demand Nutrient Delivery System

    Science.gov (United States)

    Savage, Wayne

    1998-01-01

    The goal of the proposal will be to determine the suitability of the DASI instrument in providing a signal that can be recognized and be utilized as an indicator of plant stress. The method to be utilized for evaluating stress is the presentation of an every increasing level of nutrient deficiency and salinity stress (addition of salt (NACl) or increasing concentration of balanced nutrient) while simultaneously recording spectral reflectance using the DASI instrument and monitoring the traditional processes of gas exchange and nutrient uptake parameters. In this manner, we will be able to directly compare the DASI measurements with known stresses as determined by the traditional gas exchange and nutrient uptake measures of stress. We anticipate that the DASI will provide a sensitive identifier of plant stress; recording signals of the resulting changes in plant metabolism in real time, far before any visible effects of stress could be observed. Thus, there is a potential for very early management intervention to correct a stress condition before damage could develop. The present response time for the observation of visual symptoms of plant stress is considerable and only provides an indication that a stress is present after it has been present for an extended period of time. Thus, the impact of a plant-based life support function will have already been significant. An additional benefit of this research to regenerative life support will be the characterization of a potential recovery scenario from various degrees of stress. The experimental approach to be employed includes the removal of the stress at various points in the stress gradient and the characterization of plant performance and reflectance spectra during recovery from various degrees of stress. Spectral reflectance imaging techniques have been developed and used to measure the biochemical composition of plants and relate these characteristics to the fluxes of biochemical elements within the ecosystem.

  16. Herbivores and nutrients control grassland plant diversity via light limitation.

    Energy Technology Data Exchange (ETDEWEB)

    Borer, Elizabeth T. [Department of Ecology, Evolution, and Behavior, University of Minnesota; et al, et al

    2014-01-01

    Human alterations to nutrient cycles1,2 and herbivore communities3–7 are affecting global biodiversity dramatically2. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems8,9. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

  17. Nutrient and Anti nutrient Composition of Jams Prepared from ...

    African Journals Online (AJOL)

    The nutrient composition of prepared jams was higher than that of commercially available (control) one, though commercial jam rated highest in all sensory parameters investigated. Addition of carrot extract improved the â-carotene content and acceptability of prepared jams. Conclusion: The relatively high level of -carotene ...

  18. Responses of biological and chemical components in North East Atlantic coastal water to experimental nitrogen and phosphorus addition--a full scale ecosystem study and its relevance for management.

    Science.gov (United States)

    Olsen, Yngvar; Reinertsen, Helge; Sommer, Ulrich; Vadstein, Olav

    2014-03-01

    The objective of this study was to quantify chemical and biological responses to an experimentally increased nutrient input to an open coastal planktonic ecosystem and to contribute to a scientific concept and credible indicators for managing nutrient supply to coastal waters. Data were derived in a 5 year fertilisation experiment of a tidal driven coastal lagoon at the outer coast off Central Norway (63°36' N, 9°33' E), with a surface area of 275.000 m(2), volume of 5.5 mill m(3), mean depth of 22 m and a water exchange rate of 0.19 day(-1). The lagoon was fertilised in the summer season 1998 and 1999, while summer seasons 1996-97 and 2000 and inflowing water were used as unfertilised references. Most measured chemical and biological variables showed linear responses with an increasing loading rate of inorganic N and P (LN and LP, respectively). PON, POP and POC (phytoplankton C. DIN and DIP remained, however, constant and independent of LN and LP, respectively (P>0.05) as did heterotrophic biomass (P>0.05). We evaluate the response variables assuming a stepwise incorporation process of nutrients in the planktonic ecosystem and how that will interact with biological response times and water dilution rates. We suggest that PON is a credible indicator of both chemical and ecological states of the planktonic ecosystem and that natural background and upper critical concentrations are 46 and 88 mg PON m(-3), respectively. The study was supported by data from mesocosms. We discuss the scientific relevance of our suggestions, how results can be extrapolated to a broader geographical scale, and we propose a science-based concept for the management of nutrient emission to open coastal waters. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Chronic nutrient enrichment increases prevalence and severity of coral disease and bleaching.

    Science.gov (United States)

    Vega Thurber, Rebecca L; Burkepile, Deron E; Fuchs, Corinne; Shantz, Andrew A; McMinds, Ryan; Zaneveld, Jesse R

    2014-02-01

    Nutrient loading is one of the strongest drivers of marine habitat degradation. Yet, the link between nutrients and disease epizootics in marine organisms is often tenuous and supported only by correlative data. Here, we present experimental evidence that chronic nutrient exposure leads to increases in both disease prevalence and severity and coral bleaching in scleractinian corals, the major habitat-forming organisms in tropical reefs. Over 3 years, from June 2009 to June 2012, we continuously exposed areas of a coral reef to elevated levels of nitrogen and phosphorus. At the termination of the enrichment, we surveyed over 1200 scleractinian corals for signs of disease or bleaching. Siderastrea siderea corals within enrichment plots had a twofold increase in both the prevalence and severity of disease compared with corals in unenriched control plots. In addition, elevated nutrient loading increased coral bleaching; Agaricia spp. of corals exposed to nutrients suffered a 3.5-fold increase in bleaching frequency relative to control corals, providing empirical support for a hypothesized link between nutrient loading and bleaching-induced coral declines. However, 1 year later, after nutrient enrichment had been terminated for 10 months, there were no differences in coral disease or coral bleaching prevalence between the previously enriched and control treatments. Given that our experimental enrichments were well within the ranges of ambient nutrient concentrations found on many degraded reefs worldwide, these data provide strong empirical support to the idea that coastal nutrient loading is one of the major factors contributing to the increasing levels of both coral disease and coral bleaching. Yet, these data also suggest that simple improvements to water quality may be an effective way to mitigate some coral disease epizootics and the corresponding loss of coral cover in the future. © 2013 John Wiley & Sons Ltd.

  20. Dynamic {sup 11}C-methionine PET analysis has an additional value for differentiating malignant tumors from granulomas: an experimental study using small animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Songji; Zhao, Yan [Hokkaido University, Department of Nuclear Medicine, Graduate School of Medicine, Sapporo (Japan); Hokkaido University, Department of Tracer Kinetics and Bioanalysis, Graduate School of Medicine, Sapporo (Japan); Kuge, Yuji; Hatano, Toshiyuki [Hokkaido University, Central Institute of Isotope Science, Sapporo (Japan); Yi, Min; Kohanawa, Masashi [Hokkaido University, Department of Advanced Medicine, Graduate School of Medicine, Sapporo (Japan); Magota, Keiichi; Tamaki, Nagara [Hokkaido University, Department of Nuclear Medicine, Graduate School of Medicine, Sapporo (Japan); Nishijima, Ken-ichi [Hokkaido University, Department of Molecular Imaging, Graduate School of Medicine, Sapporo (Japan)

    2011-10-15

    We evaluated whether the dynamic profile of L-{sup 11}C-methionine ({sup 11}C-MET) may have an additional value in differentiating malignant tumors from granulomas in experimental rat models by small animal positron emission tomography (PET). Rhodococcus aurantiacus and allogenic rat C6 glioma cells were inoculated, respectively, into the right and left calf muscles to generate a rat model bearing both granulomas and tumors (n = 6). Ten days after the inoculations, dynamic {sup 11}C-MET PET was performed by small animal PET up to 120 min after injection of {sup 11}C-MET. The next day, after overnight fasting, the rats were injected with {sup 18}F-2-deoxy-2-fluoro-D-glucose ({sup 18}F-FDG), and dynamic {sup 18}F-FDG PET was performed up to 180 min. The time-activity curves, static images, and mean standardized uptake value (SUV) in the lesions were calculated. {sup 11}C-MET uptake in the granuloma showed a slow exponential clearance after an initial distribution, while the uptake in the tumor gradually increased with time. The dynamic pattern of {sup 11}C-MET uptake in the granuloma was significantly different from that in the tumor (p < 0.001). In the static analysis of {sup 11}C-MET, visual assessment and SUV analysis could not differentiate the tumor from the granuloma in all cases, although the mean SUV in the granuloma (1.48 {+-} 0.09) was significantly lower than that in the tumor (1.72 {+-} 0.18, p < 0.01). The dynamic patterns, static images, and mean SUVs of {sup 18}F-FDG in the granuloma were similar to those in the tumor (p = NS). Dynamic {sup 11}C-MET PET has an additional value for differentiating malignant tumors from granulomatous lesions, which deserves further elucidation in clinical settings. (orig.)

  1. Regulating nutrient allocation in plants

    Energy Technology Data Exchange (ETDEWEB)

    Udvardi, Michael; Yang, Jiading; Worley, Eric

    2014-12-09

    The invention provides coding and promoter sequences for a VS-1 and AP-2 gene, which affects the developmental process of senescence in plants. Vectors, transgenic plants, seeds, and host cells comprising heterologous VS-1 and AP-2 genes are also provided. Additionally provided are methods of altering nutrient allocation and composition in a plant using the VS-1 and AP-2 genes.

  2. Experimental Analysis of Performance and Emission Parameters of Neem Oil Ethyl Ester and HHO Gas Addition with Neem Oil Ethyl Ester in a Single Cylinder Four Stroke Compression Ignition Engine

    National Research Council Canada - National Science Library

    M Subramanian

    2014-01-01

    .... Present work is focussed on analysing experimentally the performance and emission characteristics of Neem oil biodiesel and addition of HHO gas along with Neem oil biodiesel in a single cylinder...

  3. [Food additives and healthiness].

    Science.gov (United States)

    Heinonen, Marina

    2014-01-01

    Additives are used for improving food structure or preventing its spoilage, for example. Many substances used as additives are also naturally present in food. The safety of additives is evaluated according to commonly agreed principles. If high concentrations of an additive cause adverse health effects for humans, a limit of acceptable daily intake (ADI) is set for it. An additive is a risk only when ADI is exceeded. The healthiness of food is measured on the basis of nutrient density and scientifically proven effects.

  4. [Magnesium for nutrient].

    Science.gov (United States)

    Kimura, Mieko

    2012-08-01

    Magnesium is essential nutrient. Here is magnesium for nutrient. Magnesium has a large number of biological or biochemical functions. It's distribution, absorption, deficiency, excess disorder, requirement, supply sources, and especially status and issue of magnesium intake in Japanese are reviewed.

  5. Plant species' origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands.

    Science.gov (United States)

    Seabloom, Eric W; Borer, Elizabeth T; Buckley, Yvonne M; Cleland, Elsa E; Davies, Kendi F; Firn, Jennifer; Harpole, W Stanley; Hautier, Yann; Lind, Eric M; MacDougall, Andrew S; Orrock, John L; Prober, Suzanne M; Adler, Peter B; Anderson, T Michael; Bakker, Jonathan D; Biederman, Lori A; Blumenthal, Dana M; Brown, Cynthia S; Brudvig, Lars A; Cadotte, Marc; Chu, Chengjin; Cottingham, Kathryn L; Crawley, Michael J; Damschen, Ellen I; Dantonio, Carla M; DeCrappeo, Nicole M; Du, Guozhen; Fay, Philip A; Frater, Paul; Gruner, Daniel S; Hagenah, Nicole; Hector, Andy; Hillebrand, Helmut; Hofmockel, Kirsten S; Humphries, Hope C; Jin, Virginia L; Kay, Adam; Kirkman, Kevin P; Klein, Julia A; Knops, Johannes M H; La Pierre, Kimberly J; Ladwig, Laura; Lambrinos, John G; Li, Qi; Li, Wei; Marushia, Robin; McCulley, Rebecca L; Melbourne, Brett A; Mitchell, Charles E; Moore, Joslin L; Morgan, John; Mortensen, Brent; O'Halloran, Lydia R; Pyke, David A; Risch, Anita C; Sankaran, Mahesh; Schuetz, Martin; Simonsen, Anna; Smith, Melinda D; Stevens, Carly J; Sullivan, Lauren; Wolkovich, Elizabeth; Wragg, Peter D; Wright, Justin; Yang, Louie

    2015-07-15

    Exotic species dominate many communities; however the functional significance of species' biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands.

  6. Addition of gentamicin or rifampin does not enhance the effectiveness of daptomycin in treatment of experimental endocarditis due to methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Miró, J M; García-de-la-Mària, C; Armero, Y; Soy, D; Moreno, A; del Río, A; Almela, M; Sarasa, M; Mestres, C A; Gatell, J M; Jiménez de Anta, M T; Marco, F

    2009-10-01

    This study evaluated the activity of daptomycin combined with either gentamicin or rifampin against three methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates in vitro and one isolate in vivo against a representative strain (MRSA-572). Time-kill experiments showed that daptomycin was bactericidal against these strains at concentrations over the MIC. Daptomycin at sub-MIC concentrations plus gentamicin at 1x and 2x the MIC yielded synergy, while the addition of rifampin at 2 to 4 microg/ml resulted in indifference (two strains) or antagonism (one strain). The in vivo activity of daptomycin (6 mg/kg of body weight once a day) was evaluated +/- gentamicin (1 mg/kg intravenously [i.v.] every 8 h [q8h]) or rifampin (300 mg i.v. q8h) in a rabbit model of infective endocarditis by simulating human pharmacokinetics. Daptomycin plus gentamicin (median, 0 [interquartile range, 0 to 2] log10 CFU/g vegetation) was as effective as daptomycin alone (0 [0 to 2] log10 CFU/g vegetation) in reducing the density of bacteria in valve vegetations (P = 0.83), and both were more effective than daptomycin plus rifampin (3 [2 to 3.5] log10 CFU/g vegetation; P gentamicin (10/15 [67%] versus 9/15 [60%]; P = 0.7), and both regimens did so more than daptomycin plus rifampin (3/15 [20%]; P = 0.01 and P = 0.02, respectively). No statistical difference was noted between daptomycin plus gentamicin and daptomycin alone for MRSA treatment. In the combination arm, all isolates from vegetations remained susceptible to daptomycin, gentamicin, and rifampin. Sixty-one percent of the isolates (8/13) acquired resistance to rifampin during monotherapy. In the daptomycin arm, resistance was detected in only one case, in which the daptomycin MIC rose to 2 microg/ml among the recovered bacteria. In conclusion, the addition of gentamicin or rifampin does not enhance the effectiveness of daptomycin in the treatment of experimental endocarditis due to MRSA.

  7. Soluble organic nutrient fluxes

    Science.gov (United States)

    Robert G. Qualls; Bruce L. Haines; Wayne Swank

    2014-01-01

    Our objectives in this study were (i) compare fluxes of the dissolved organic nutrients dissolved organic carbon (DOC), DON, and dissolved organic phosphorus (DOP) in a clearcut area and an adjacent mature reference area. (ii) determine whether concentrations of dissolved organic nutrients or inorganic nutrients were greater in clearcut areas than in reference areas,...

  8. The Impact of Food and Nutrient-Based Standards on Primary School Children’s Lunch and Total Dietary Intake: A Natural Experimental Evaluation of Government Policy in England

    Science.gov (United States)

    Spence, Suzanne; Delve, Jennifer; Stamp, Elaine; Matthews, John N. S.; White, Martin; Adamson, Ashley J.

    2013-01-01

    In 2005, the nutritional content of children’s school lunches in England was widely criticised, leading to a major policy change in 2006. Food and nutrient-based standards were reintroduced requiring primary schools to comply by September 2008. We aimed to determine the effect of the policy on the nutritional content at lunchtime and in children’s total diet. We undertook a natural experimental evaluation, analysing data from cross-sectional surveys in 12 primary schools in North East England, pre and post policy. Dietary data were collected on four consecutive days from children aged 4–7 years (n = 385 in 2003–4; n = 632 in 2008–9). We used linear mixed effect models to analyse the effects of gender, year, and lunch type on children’s mean total daily intake. Both pre- and post-implementation, children who ate a school lunch consumed less sodium (mean change −128 mg, 95% CI: −183 to −73 mg) in their total diet than children eating home-packed lunches. Post-implementation, children eating school lunches consumed a lower % energy from fat (−1.8%, −2.8 to −0.9) and saturated fat (−1.0%; −1.6 to −0.5) than children eating packed lunches. Children eating school lunches post implementation consumed significantly more carbohydrate (16.4 g, 5.3 to 27.6), protein (3.6 g, 1.1 to 6.0), non-starch polysaccharides (1.5 g, 0.5 to 1.9), vitamin C (0.7 mg, 0.6 to 0.8), and folate (12.3 µg, 9.7 to 20.4) in their total diet than children eating packed lunches. Implementation of school food policy standards was associated with significant improvements in the nutritional content of school lunches; this was reflected in children’s total diet. School food- and nutrient-based standards can play an important role in promoting dietary health and may contribute to tackling childhood obesity. Similar policy measures should be considered for other environments influencing children’s diet. PMID:24205190

  9. Processes and patterns of oceanic nutrient limitation

    Science.gov (United States)

    Moore, C. M.; Mills, M. M.; Arrigo, K. R.; Berman-Frank, I.; Bopp, L.; Boyd, P. W.; Galbraith, E. D.; Geider, R. J.; Guieu, C.; Jaccard, S. L.; Jickells, T. D.; La Roche, J.; Lenton, T. M.; Mahowald, N. M.; Marañón, E.; Marinov, I.; Moore, J. K.; Nakatsuka, T.; Oschlies, A.; Saito, M. A.; Thingstad, T. F.; Tsuda, A.; Ulloa, O.

    2013-09-01

    Microbial activity is a fundamental component of oceanic nutrient cycles. Photosynthetic microbes, collectively termed phytoplankton, are responsible for the vast majority of primary production in marine waters. The availability of nutrients in the upper ocean frequently limits the activity and abundance of these organisms. Experimental data have revealed two broad regimes of phytoplankton nutrient limitation in the modern upper ocean. Nitrogen availability tends to limit productivity throughout much of the surface low-latitude ocean, where the supply of nutrients from the subsurface is relatively slow. In contrast, iron often limits productivity where subsurface nutrient supply is enhanced, including within the main oceanic upwelling regions of the Southern Ocean and the eastern equatorial Pacific. Phosphorus, vitamins and micronutrients other than iron may also (co-)limit marine phytoplankton. The spatial patterns and importance of co-limitation, however, remain unclear. Variability in the stoichiometries of nutrient supply and biological demand are key determinants of oceanic nutrient limitation. Deciphering the mechanisms that underpin this variability, and the consequences for marine microbes, will be a challenge. But such knowledge will be crucial for accurately predicting the consequences of ongoing anthropogenic perturbations to oceanic nutrient biogeochemistry.

  10. Short-Term Effects of Drying-Rewetting and Long-Term Effects of Nutrient Loading on Periphyton N:P Stoichiometry

    Directory of Open Access Journals (Sweden)

    Andres D. Sola

    2018-01-01

    Full Text Available Nitrogen (N and phosphorus (P concentrations and N:P ratios critically influence periphyton productivity and nutrient cycling in aquatic ecosystems. In coastal wetlands, variations in hydrology and water source (fresh or marine influence nutrient availability, but short-term effects of drying and rewetting and long-term effects of nutrient exposure on periphyton nutrient retention are uncertain. An outdoor microcosm experiment simulated short-term exposure to variation in drying-rewetting frequency on periphyton mat nutrient retention. A 13-year dataset from freshwater marshes of the Florida Everglades was examined for the effect of long-term proximity to different N and P sources on mat-forming periphyton nutrient standing stocks and stoichiometry. Field sites were selected from one drainage with shorter hydroperiod and higher connectivity to freshwater anthropogenic nutrient supplies (Taylor Slough/Panhandle, TS/Ph and another drainage with longer hydroperiod and higher connectivity to marine nutrient supplies (Shark River Slough, SRS. Total P, but not total N, increased in periphyton mats exposed to both low and high drying-rewetting frequency with respect to the control mats in our experimental microcosm. In SRS, N:P ratios slightly decreased downstream due to marine nutrient supplies, while TS/Ph increased. Mats exposed to short-term drying-rewetting had higher nutrient retention, similar to nutrient standing stocks from long-term field data. Periphyton mat microbial communities may undergo community shifts upon drying-rewetting and chronic exposure to nutrient loads. Additional work on microbial species composition may further explain how periphyton communities interact with drying-rewetting dynamics to influence nutrient cycling and retention in wetlands.

  11. Drug-nutrient interactions.

    Science.gov (United States)

    Chan, Lingtak-Neander

    2013-07-01

    Drug-nutrient interactions are defined as physical, chemical, physiologic, or pathophysiologic relationships between a drug and a nutrient. The causes of most clinically significant drug-nutrient interactions are usually multifactorial. Failure to identify and properly manage drug-nutrient interactions can lead to very serious consequences and have a negative impact on patient outcomes. Nevertheless, with thorough review and assessment of the patient's history and treatment regimens and a carefully executed management strategy, adverse events associated with drug-nutrient interactions can be prevented. Based on the physiologic sequence of events after a drug or a nutrient has entered the body and the mechanism of interactions, drug-nutrient interactions can be categorized into 4 main types. Each type of interaction can be managed using similar strategies. The existing data that guide the clinical management of most drug-nutrient interactions are mostly anecdotal experience, uncontrolled observations, and opinions, whereas the science in understanding the mechanism of drug-nutrient interactions remains limited. The challenge for researchers and clinicians is to increase both basic and higher level clinical research in this field to bridge the gap between the science and practice. The research should aim to establish a better understanding of the function, regulation, and substrate specificity of the nutrient-related enzymes and transport proteins present in the gastrointestinal tract, as well as assess how the incidence and management of drug-nutrient interactions can be affected by sex, ethnicity, environmental factors, and genetic polymorphisms. This knowledge can help us develop a true personalized medicine approach in the prevention and management of drug-nutrient interactions.

  12. A gradient of nutrient enrichment reveals nonlinear impacts of fertilization on Arctic plant diversity and ecosystem function.

    Science.gov (United States)

    Prager, Case M; Naeem, Shahid; Boelman, Natalie T; Eitel, Jan U H; Greaves, Heather E; Heskel, Mary A; Magney, Troy S; Menge, Duncan N L; Vierling, Lee A; Griffin, Kevin L

    2017-04-01

    Rapid environmental change at high latitudes is predicted to greatly alter the diversity, structure, and function of plant communities, resulting in changes in the pools and fluxes of nutrients. In Arctic tundra, increased nitrogen (N) and phosphorus (P) availability accompanying warming is known to impact plant diversity and ecosystem function; however, to date, most studies examining Arctic nutrient enrichment focus on the impact of relatively large (>25x estimated naturally occurring N enrichment) doses of nutrients on plant community composition and net primary productivity. To understand the impacts of Arctic nutrient enrichment, we examined plant community composition and the capacity for ecosystem function (net ecosystem exchange, ecosystem respiration, and gross primary production) across a gradient of experimental N and P addition expected to more closely approximate warming-induced fertilization. In addition, we compared our measured ecosystem CO 2 flux data to a widely used Arctic ecosystem exchange model to investigate the ability to predict the capacity for CO 2 exchange with nutrient addition. We observed declines in abundance-weighted plant diversity at low levels of nutrient enrichment, but species richness and the capacity for ecosystem carbon uptake did not change until the highest level of fertilization. When we compared our measured data to the model, we found that the model explained roughly 30%-50% of the variance in the observed data, depending on the flux variable, and the relationship weakened at high levels of enrichment. Our results suggest that while a relatively small amount of nutrient enrichment impacts plant diversity, only relatively large levels of fertilization-over an order of magnitude or more than warming-induced rates-significantly alter the capacity for tundra CO 2 exchange. Overall, our findings highlight the value of measuring and modeling the impacts of a nutrient enrichment gradient, as warming-related nutrient

  13. Long-term calcium addition increases growth release, wound closure, and health of sugar maple (Acer saccharum) trees at the Hubbard Brook Experimental Forest

    Science.gov (United States)

    Brett A. Huggett; Paul G. Schaberg; Gary J. Hawley; Christopher Eager

    2007-01-01

    We surveyed and wounded forest-grown sugar maple (Acer saccharum Marsh.) trees in a long-term, replicated Ca manipulation study at the Hubbard Brook Experimental Forest in New Hampshire, USA. Plots received applications of Ca (to boost Ca availability above depleted ambient levels) or A1 (to compete with Ca uptake and further reduce Ca availability...

  14. Spectral Quantitation Of Hydroponic Nutrients

    Science.gov (United States)

    Schlager, Kenneth J.; Kahle, Scott J.; Wilson, Monica A.; Boehlen, Michelle

    1996-01-01

    Instrument continuously monitors hydroponic solution by use of absorption and emission spectrometry to determine concentrations of principal nutrients, including nitrate, iron, potassium, calcium, magnesium, phosphorus, sodium, and others. Does not depend on extraction and processing of samples, use of such surrograte parameters as pH or electrical conductivity for control, or addition of analytical reagents to solution. Solution not chemically altered by analysis and can be returned to hydroponic process stream after analysis.

  15. [New nutrients in enteral nutrition].

    Science.gov (United States)

    Vázquez Martínez, C

    2000-01-01

    1. Medical and surgical stress (major surgery, sepsis, injuries,...) increases requirements of certain essential nutrients and others considered non-essential or semi-essential. 2. Some nutrients such as glutamine, arginine, omega 3 fatty acids nucleotides, ... have a considerable influence on the immune function (delayed hypersensitivity, lymphocyte sub-population counts, immunological tests,..) and improve certain metabolic and nutritional indices (nitrogen balance, medium and short life proteins,...). For this reason, they are called "immunonutrients" or "immunity regulators". 3. The supply of special enteral formulas for situations of immunological compromise, with the addition of one or more of the nutrients considered today as "immunity regulators" has increased since 1988 in both absolute and percentage terms. 4. These nutrient-enriched enteral formulas improve the rate of infections, reduce the number of days on ventilator equipment, the length of hospital stays for critical patients, with a more marked effect on surgical patients. 5. The evidence seems today to support the use of enriched formulas with critical patients. Nonetheless, some caution must be maintained as it has not been possible to show any reduction in the mortality of the cases studied nor, in short, in the prognosis of patients affected by situations of hypercatabolism and reduced immunity. 6. We feel that their use should, therefore, be carried out in accordance with the protocols and in patients expected to survive, where the evolution reveals severe catabolism unhindered by conventional therapy.

  16. Sponge-Microbe Associations Survive High Nutrients and Temperatures

    Science.gov (United States)

    Simister, Rachel; Taylor, Michael W.; Tsai, Peter; Webster, Nicole

    2012-01-01

    Coral reefs are under considerable pressure from global stressors such as elevated sea surface temperature and ocean acidification, as well as local factors including eutrophication and poor water quality. Marine sponges are diverse, abundant and ecologically important components of coral reefs in both coastal and offshore environments. Due to their exceptionally high filtration rates, sponges also form a crucial coupling point between benthic and pelagic habitats. Sponges harbor extensive microbial communities, with many microbial phylotypes found exclusively in sponges and thought to contribute to the health and survival of their hosts. Manipulative experiments were undertaken to ascertain the impact of elevated nutrients and seawater temperature on health and microbial community dynamics in the Great Barrier Reef sponge Rhopaloeides odorabile. R. odorabile exposed to elevated nutrient levels including 10 µmol/L total nitrogen at 31°C appeared visually similar to those maintained under ambient seawater conditions after 7 days. The symbiotic microbial community, analyzed by 16S rRNA gene pyrotag sequencing, was highly conserved for the duration of the experiment at both phylum and operational taxonomic unit (OTU) (97% sequence similarity) levels with 19 bacterial phyla and 1743 OTUs identified across all samples. Additionally, elevated nutrients and temperatures did not alter the archaeal associations in R. odorabile, with sequencing of 16S rRNA gene libraries revealing similar Thaumarchaeota diversity and denaturing gradient gel electrophoresis (DGGE) revealing consistent amoA gene patterns, across all experimental treatments. A conserved eukaryotic community was also identified across all nutrient and temperature treatments by DGGE. The highly stable microbial associations indicate that R. odorabile symbionts are capable of withstanding short-term exposure to elevated nutrient concentrations and sub-lethal temperatures. PMID:23284943

  17. Sponge-microbe associations survive high nutrients and temperatures.

    Directory of Open Access Journals (Sweden)

    Rachel Simister

    Full Text Available Coral reefs are under considerable pressure from global stressors such as elevated sea surface temperature and ocean acidification, as well as local factors including eutrophication and poor water quality. Marine sponges are diverse, abundant and ecologically important components of coral reefs in both coastal and offshore environments. Due to their exceptionally high filtration rates, sponges also form a crucial coupling point between benthic and pelagic habitats. Sponges harbor extensive microbial communities, with many microbial phylotypes found exclusively in sponges and thought to contribute to the health and survival of their hosts. Manipulative experiments were undertaken to ascertain the impact of elevated nutrients and seawater temperature on health and microbial community dynamics in the Great Barrier Reef sponge Rhopaloeides odorabile. R. odorabile exposed to elevated nutrient levels including 10 µmol/L total nitrogen at 31°C appeared visually similar to those maintained under ambient seawater conditions after 7 days. The symbiotic microbial community, analyzed by 16S rRNA gene pyrotag sequencing, was highly conserved for the duration of the experiment at both phylum and operational taxonomic unit (OTU (97% sequence similarity levels with 19 bacterial phyla and 1743 OTUs identified across all samples. Additionally, elevated nutrients and temperatures did not alter the archaeal associations in R. odorabile, with sequencing of 16S rRNA gene libraries revealing similar Thaumarchaeota diversity and denaturing gradient gel electrophoresis (DGGE revealing consistent amoA gene patterns, across all experimental treatments. A conserved eukaryotic community was also identified across all nutrient and temperature treatments by DGGE. The highly stable microbial associations indicate that R. odorabile symbionts are capable of withstanding short-term exposure to elevated nutrient concentrations and sub-lethal temperatures.

  18. Nutrient enrichment increases mortality of mangroves.

    Directory of Open Access Journals (Sweden)

    Catherine E Lovelock

    Full Text Available Nutrient enrichment of the coastal zone places intense pressure on marine communities. Previous studies have shown that growth of intertidal mangrove forests is accelerated with enhanced nutrient availability. However, nutrient enrichment favours growth of shoots relative to roots, thus enhancing growth rates but increasing vulnerability to environmental stresses that adversely affect plant water relations. Two such stresses are high salinity and low humidity, both of which require greater investment in roots to meet the demands for water by the shoots. Here we present data from a global network of sites that documents enhanced mortality of mangroves with experimental nutrient enrichment at sites where high sediment salinity was coincident with low rainfall and low humidity. Thus the benefits of increased mangrove growth in response to coastal eutrophication is offset by the costs of decreased resilience due to mortality during drought, with mortality increasing with soil water salinity along climatic gradients.

  19. Ecosystem partitioning of 15N-glycine after long-term climate and nutrient manipulations, plant clipping and addition of labile carbon in a subarctic heath tundra

    DEFF Research Database (Denmark)

    Sørensen, Pernille Lærkedal; Michelsen, Anders; Jonasson, Sven Evert

    2008-01-01

    Low temperatures and high soil moisture restrict cycling of organic matter in arctic soils, but also substrate quality, i.e. labile carbon (C) availability, exerts control on microbial activity. Plant exudation of labile C may facilitate microbial growth and enhance microbial immobilization......, microorganisms and plants. There were few effects of long-term warming and fertilization on soil and plant pools. However, fertilization increased soil and plant N pools and increased pool dilution of the added 15N label. In all treatments, microbes immobilized a major part of the added 15N shortly after label...... addition. However, plants exerted control on the soil inorganic N concentrations and recovery of total dissolved 15N (TD15N), and likewise the microbes reduced these soil pools, but only when fed with labile C. Soil microbes in clipped plots were primarily C limited, and the findings of reduced N...

  20. Essential Nutrients, Feed Classification and Nutrient Content of Feeds

    OpenAIRE

    Hall, John Burton, 1960-; Seay, William W.; Baker, Scott M., 1968-

    2005-01-01

    The cow-calf herd's primary source of nutrition is forages, but forages are variable in nutrient content. By knowing the nutrient content of their base forages, producers can then identify the deficient nutrients that need to be supplemented.

  1. Biomechanical efficacy of monoaxial or polyaxial pedicle screw and additional screw insertion at the level of fracture, in lumbar burst fracture: An experimental study

    Directory of Open Access Journals (Sweden)

    Hongwei Wang

    2012-01-01

    Conclusions: The addition of intermediate screws at the level of a burst fracture significantly increased the stability of short-segment pedicle screw fixation in both the MPS and PPS groups. However, in short-segment fixation group, monoaxial pedicle screw exhibited more stability in flexion and extension than the polyaxial pedicle screw.

  2. Calcium addition at the Hubbard Brook Experimental Forest increases sugar storage, antioxidant activity and cold tolerance in native red spruce (Picea rubens)

    Science.gov (United States)

    Joshua M. Halman; Paul G. Schaberg; Gary J. Hawley; Christopher Eagar

    2008-01-01

    In fall (November 2005) and winter (February 2006), we collected current-year foliage of native red spruce (Picea rubens Sarg.) growing in a reference watershed and in a watershed treated in 1999 with wollastonite (CaSiO3, a slow-release calcium source) to simulate preindustrial soil calcium concentrations (Ca-addition...

  3. Calcium addition at the Hubbard Brook Experimental Forest increases the capacity for stress tolerance and carbon capture in red spruce (Picea rubens) trees during the cold season

    Science.gov (United States)

    Paul G. Schaberg; Rakesh Minocha; Stephanie Long; Joshua M. Halman; Gary J. Hawley; Christopher. Eagar

    2011-01-01

    Red spruce (Picea rubens Sarg.) trees are uniquely vulnerable to foliar freezing injury during the cold season (fall and winter), but are also capable of photosynthetic activity if temperatures moderate. To evaluate the influence of calcium (Ca) addition on the physiology of red spruce during the cold season, we measured concentrations of foliar...

  4. Automated nutrient analyses in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Whitledge, T.E.; Malloy, S.C.; Patton, C.J.; Wirick, C.D.

    1981-02-01

    This manual was assembled for use as a guide for analyzing the nutrient content of seawater samples collected in the marine coastal zone of the Northeast United States and the Bering Sea. Some modifications (changes in dilution or sample pump tube sizes) may be necessary to achieve optimum measurements in very pronounced oligotrophic, eutrophic or brackish areas. Information is presented under the following section headings: theory and mechanics of automated analysis; continuous flow system description; operation of autoanalyzer system; cookbook of current nutrient methods; automated analyzer and data analysis software; computer interfacing and hardware modifications; and trouble shooting. The three appendixes are entitled: references and additional reading; manifold components and chemicals; and software listings. (JGB)

  5. High organic carbon export precludes eutrophication responses in experimental rocky shore communities

    NARCIS (Netherlands)

    Barrón, C.; Marbu, N.; Duarte, C.M.; Pedersen, M.F.; Lindblad, C.; Kersting, K.; Moy, F.; Bokn, T.

    2003-01-01

    We studied the effect of nutrient inputs on the carbon (C) budget of rocky shore communities using a set of eight large experimental mesocosms. The mesocosms received a range of inorganic nitrogen (N) and phosphorus (P) additions, at an N:P ratio of 16. These additions were designed to elevate the

  6. Experimental evidence of formation of transparent exopolymer particles (TEP) and POC export provoked by dust addition under current and high pCO2 conditions.

    Science.gov (United States)

    Louis, Justine; Pedrotti, Maria Luiza; Gazeau, Frédéric; Guieu, Cécile

    2017-01-01

    The evolution of organic carbon export to the deep ocean, under anthropogenic forcing such as ocean warming and acidification, needs to be investigated in order to evaluate potential positive or negative feedbacks on atmospheric CO2 concentrations, and therefore on climate. As such, modifications of aggregation processes driven by transparent exopolymer particles (TEP) formation have the potential to affect carbon export. The objectives of this study were to experimentally assess the dynamics of organic matter, after the simulation of a Saharan dust deposition event, through the measurement over one week of TEP abundance and size, and to evaluate the effects of ocean acidification on TEP formation and carbon export following a dust deposition event. Three experiments were performed in the laboratory using 300 L tanks filled with filtered seawater collected in the Mediterranean Sea, during two 'no bloom' periods (spring at the start of the stratification period and autumn at the end of this stratification period) and during the winter bloom period. For each experiment, one of the two tanks was acidified to reach pH conditions slightly below values projected for 2100 (~ 7.6-7.8). In both tanks, a dust deposition event of 10 g m-2 was simulated at the surface. Our results suggest that Saharan dust deposition triggered the abiotic formation of TEP, leading to the formation of organic-mineral aggregates. The amount of particulate organic carbon (POC) exported was proportional to the flux of lithogenic particles to the sediment traps. Depending on the season, the POC flux following artificial dust deposition ranged between 38 and 90 mg m-2 over six experimental days. Such variability is likely linked to the seasonal differences in the quality and quantity of TEP-precursors initially present in seawater. Finally, these export fluxes were not significantly different at the completion of the three experiments between the two pH conditions.

  7. Nutrient Limitation of Microbial Mediated Decomposition and Arctic Soil Chronology

    Science.gov (United States)

    Melle, C. J.; Darrouzet-Nardi, A.; Wallenstein, M. D.

    2012-12-01

    effective soil age. My research is focused on addressing the questions of the extent of microbial N limitation in arctic tundra soils, the potential for co-limitation of labile C despite a high SOC environment, and the dependence, if any, nutrient limitation may have on the effective age of the soil. I have addressed these questions by conducting a laboratory soil incubation of factorial design with treatments of amended glucose, amended ammonium nitrate, and a control consisting of an addition of an equivalent volume of deionized water. Moist acid tundra soils possessing similar soil properties from two arctic sites of close proximity yet with varying deglaciation chronologies were utilized in my study. Soil properties of C-mineralization via respiration, microbial biomass, and nitrogen content in the forms of ammonium, nitrate, and total free amino acids and microbial extra-cellular enzyme production were assayed to determine the microbial response to the experimental treatments. Through the results of this work, I hope to better our understanding of biogeochemical cycling within arctic tundra ecosystems and the response to climate change by contributing to existing knowledge of nutrient limitation on microbial mediated decomposition of SOC in the arctic and how this may differ in soils of varying effective age.

  8. Effect of dilution rate and nutrients addition on the fermentative capability and synthesis of aromatic compounds of two indigenous strains of Saccharomyces cerevisiae in continuous cultures fed with Agave tequilana juice.

    Science.gov (United States)

    Morán-Marroquín, G A; Córdova, J; Valle-Rodríguez, J O; Estarrón-Espinosa, M; Díaz-Montaño, D M

    2011-11-15

    Knowledge of physiological behavior of indigenous tequila yeast used in fermentation process is still limited. Yeasts have significant impact on the productivity fermentation process as well as the sensorial characteristics of the alcoholic beverage. For these reasons a better knowledge of the physiological and metabolic features of these yeasts is required. The effects of dilution rate, nitrogen and phosphorus source addition and micro-aeration on growth, fermentation and synthesis of volatile compounds of two native Saccharomyces cerevisiae strains, cultured in continuous fed with Agave tequilana juice were studied. For S1 and S2 strains, maximal concentrations of biomass, ethanol, consumed sugars, alcohols and esters were obtained at 0.04 h⁻¹. Those concentrations quickly decreased as D increased. For S. cerevisiae S1 cultures (at D=0.08 h⁻¹) supplemented with ammonium phosphate (AP) from 1 to 4 g/L, concentrations of residual sugars decreased from 29.42 to 17.60 g/L and ethanol increased from 29.63 to 40.08 g/L, respectively. The S1 culture supplemented with AP was then micro-aerated from 0 to 0.02 vvm, improving all the kinetics parameters: biomass, ethanol and glycerol concentrations increased from 5.66, 40.08 and 3.11 g/L to 8.04, 45.91 and 4.88 g/L; residual sugars decreased from 17.67 g/L to 4.48 g/L; and rates of productions of biomass and ethanol, and consumption of sugars increased from 0.45, 3.21 and 7.33 g/L·h to 0.64, 3.67 and 8.38 g/L·h, respectively. Concentrations of volatile compounds were also influenced by the micro-aeration rate. Ester and alcohol concentrations were higher, in none aerated and in aerated cultures respectively. Copyright © 2011. Published by Elsevier B.V.

  9. EXPERIMENTAL EVIDENCE FOR THE FORMATION OF HIGHLY SUPERHYDROGENATED POLYCYCLIC AROMATIC HYDROCARBONS THROUGH H ATOM ADDITION AND THEIR CATALYTIC ROLE IN H2 FORMATION

    DEFF Research Database (Denmark)

    Thrower, John; Jørgensen, Bjarke; Friis, Emil Enderup

    2012-01-01

    Mass spectrometry measurements show the formation of highly superhydrogenated derivatives of the polycyclic aromatic hydrocarbon molecule coronene through H atom addition reactions. The observed product mass distribution provides evidence also for abstraction reactions resulting in H2 formation......, in agreement with recent IR measurements. Complementary density functional theory calculations confirm the stability of the observed superhydrogenated species toward spontaneous H and H2 loss indicating that abstraction reactions may be the dominant route to H2 formation involving neutral polycyclic aromatic...... hydrocarbons (PAHs). The results indicate that highly superhydrogenated PAHs could well be formed and could act as efficient catalysts for H2 formation in the interstellar medium in low UV flux regions....

  10. The effect of anethole containing essentials oils on nutrients digestibility of pigs

    Directory of Open Access Journals (Sweden)

    Ladislav Zeman

    2009-01-01

    Full Text Available The plant additives and their functional components can selectively influence the intestinal microorganism growth in positive or negative direction. If the growth promotion relates with positive microorganisms and growth elimination is connected with pathogens the results is nutrients utilization improvement, stimulation of immunologic system or positive influence of intermedial metabolism. Anethole is one of these important plant metabolites. There are described following positive effects of anethole in human medicine: vasorelaxant, antithrombotic, releasing of heart function, fytoestrogenic (it mean improving of milk secretion, menstruation, promotion of menses, birth improvement, men’s hormonal changes improving, sexual libido improving, antioxidative, antifungal, improvement of derma permeability, antihelmintic, insecticidal, yeast elimination, antibacterial, antipyretic.In our work the effect of anise and fennel essential oils on nutrients utilization in pig experiment was evaluated. The trial was organized in accredited experimental stable Žabčice of Mendel University of Agriculture and Forestry Brno. The high level efficiency of experimental animals is mentioned through general parameters (average daily gain, feed intake and feed conversion. The results of nutrients utilization rate show slightly higher digestibility of nutrients in treatment with anise oil, this improvement is not higher then 1.0 %. We can see also improvement of nitrogen retention in body mass on level of 5.6 % (anise treatment compared with control group. There is low variability between experimental animals (except nitrogen retention coefficient but we can not see any statistical significance. On base of these results we can say the used phytogenic additives do not affect negatively the nutrient utilization in used concentration (0.1 % of essential oil in feed mixture and are fully eligible for animal nutrition. These results are also supported by few

  11. Pre- and post-experimental manipulation assessments confirm the increase in number of birds due to the addition of nest boxes

    Directory of Open Access Journals (Sweden)

    Cecilia Cuatianquiz Lima

    2016-03-01

    Full Text Available Secondary cavity nesting (SCN birds breed in holes that they do not excavate themselves. This is possible where there are large trees whose size and age permit the digging of holes by primary excavators and only rarely happens in forest plantations, where we expected a deficit of both breeding holes and SCN species. We assessed whether the availability of tree cavities influenced the number of SCNs in two temperate forest types, and evaluated the change in number of SCNs after adding nest boxes. First, we counted all cavities within each of our 25-m radius sampling points in mature and young forest plots during 2009. We then added nest boxes at standardised locations during 2010 and 2011 and conducted fortnightly bird counts (January–October 2009–2011. In 2011 we added two extra plots of each forest type, where we also conducted bird counts. Prior to adding nest boxes, counts revealed more SCNs in mature than in young forest. Following the addition of nest boxes, the number of SCNs increased significantly in the points with nest boxes in both types of forest. Counts in 2011 confirmed the increase in number of birds due to the addition of nest boxes. Given the likely benefits associated with a richer bird community we propose that, as is routinely done in some countries, forest management programs preserve old tree stumps and add nest boxes to forest plantations in order to increase bird numbers and bird community diversity.

  12. Late gestational nutrient restriction

    DEFF Research Database (Denmark)

    Tygesen, Malin Plumhoff; Nielsen, Mette Olaf; Nørgaard, Peder

    2008-01-01

    We investigated the effect of 50% nutrient restriction during the last 6 weeks of gestation on twin-pregnant ewes' plasma glucose, non-esterified fatty acid, beta-hydroxybutyrate, insulin, IGF-1 and leptin concentrations and the effects on lamb birth weight and ewes' lactation performance. Plasma...... changes in feed intake and energy balance. It is concluded that severely reduced nutrient availability in late gestation affects fetal growth in utero and has a prolonged negative effect on lactation performance....

  13. Nutrient limitation and plant species composition in temperate salt marshes

    NARCIS (Netherlands)

    Kiehl, K.; Esselink, P.; Bakker, JP

    Addition of inorganic nitrogen, phosphorus and potassium in a factorial design in two ungrazed Wadden-Sea salt marshes at low and high elevations showed that nitrogen was the limiting nutrient. No effects of nutrient addition were detected in the Ist year, probably due to a considerable rainfall

  14. Effects of experimental warming and nitrogen addition on soil respiration and CH4 fluxes from crop rotations of winter wheat–soybean/fallow

    DEFF Research Database (Denmark)

    Liu, L; Hu, C; Yang, P

    2015-01-01

    Soil respiration and CH4 emissions play a significant role in the global carbon balance. However, in situ studies in agricultural soils on responses of soil respiration and CH4 fluxes to climate warming are still sparse, especially from long-term studies with year-round heating. A warming...... by affecting soil NH4 concentration. Across years, CH4 emissions were negatively correlated with soil temperature in N1 treatment. Soil respiration showed clear seasonal fluctuations, with the largest emissions during summer and smallest in winter. Warming and nitrogen fertilization had no significant effects...... on total cumulative soil CO2 fluxes. Soil respiration was positively correlated with microbial biomass C, and microbial biomass C was not affected significantly by warming or nitrogen addition. The lack of significant effects of warming on soil respiration may have resulted from: (1) warming-induced soil...

  15. Numerical and experimental investigation of light emissions of a planar nitrogen atmospheric-pressure dielectric barrier discharge due to addition of ammonia considering oxygen impurity

    Science.gov (United States)

    Li, F.-L.; Hung, C.-T.; Lin, K.-M.; Wei, T.-C.; Wu, J.-S.

    2013-12-01

    In this paper, the mechanisms of light emissions, including NO-γ, NO-β and N2-SPS, produced in a N2/NH3 atmospheric-pressure dielectric barrier discharge considering realistic oxygen impurity (30 ppm) are investigated numerically and experimentally. Self-consistent, one-dimensional fluid modeling is used to numerically simulate the discharge process with 48 species and 235 reaction channels. An optical emission spectrometer (OES) is used to measure the relative intensities of the light emission. The simulations of the light emission intensities for the above-mentioned OES lines generally reproduce the trends observed in the experiments caused by changes in the NH3 concentration. All of the predicted intensities of NO-γ, NO-β and N2-SPS decrease with increasing amount of NH3 caused by various reaction mechanisms. The former is due to the loss of N2(A) and NO(A) by the reaction of NH3 with N2(A) and NO(A), respectively. The decrease in NO-β is due to the depletion of N and O because of NH3, and the decrease in N2-SPS is due to electron attachment to NH3 and a weaker metastable-metastable associative ionization of N2. All of the simulated results demonstrate that the discharges are typically Townsend-like because the ions outnumber the electrons and the electric field across the gap is distorted only slightly by the charged particles during the breakdown. Finally, a reduced chemical kinetics model for a planar atmospheric-pressure N2/O2/NH3 dielectric barrier discharge is proposed and validated by benchmarking against the above complete chemical kinetics. This results in a reduced chemical kinetics consisting of 33 species and 87 reactions with a very limited loss of accuracy of discharge properties, while it is 2.1 times faster in computational time as compared with the complete version.

  16. Kinin B1 receptor antagonism is equally efficient as angiotensin receptor 1 antagonism in reducing renal fibrosis in experimental obstructive nephropathy, but is not additive.

    Directory of Open Access Journals (Sweden)

    Antoine eHuart

    2015-02-01

    Full Text Available Background: Renal tubulointerstitial fibrosis is the pathological hallmark of chronic kidney disease. Currently, inhibitors of the renin angiotensin system (RAS remain the sole therapy in human displaying antifibrotic properties. Further antifibrotic molecules are needed. We have recently reported that the delayed blockade of the bradykinin B1 receptor (B1R reduced the development of fibrosis in two animal models of renal fibrosis. The usefulness of new drugs also resides in outperforming the gold standards and eventually being additive or complementary to existing therapies. Methods: In this study we compared the efficacy of a B1R antagonist (B1Ra with that of an angiotensin type 1 receptor antagonist (AT1a in the unilateral ureteral obstruction (UUO model of renal fibrosis and determined whether bi-therapy presented higher efficacy than any of the drugs alone. Results: B1R antagonism was as efficient as the gold-standard AT1a treatment. However bitherapy did not improve the antifibrotic effects at the protein level. We sought for the reason of the absence of this additive effect by studying the expression of a panel of genes involved in the fibrotic process. Interestingly, at the molecular level the different drugs targeted different players of fibrosis that, however, in this severe model did not result in improved reduction of fibrosis at the protein level. Conclusions: As the B1R is induced specifically in the diseased organ and thus potentially displays low side effects it might be an interesting alternative in cases of poor tolerability to RAS inhibitors.

  17. Kinin B1 receptor antagonism is equally efficient as angiotensin receptor 1 antagonism in reducing renal fibrosis in experimental obstructive nephropathy, but is not additive

    Science.gov (United States)

    Huart, Antoine; Klein, Julie; Gonzalez, Julien; Buffin-Meyer, Bénédicte; Neau, Eric; Delage, Christine; Calise, Denis; Ribes, David; Schanstra, Joost P.; Bascands, Jean-Loup

    2015-01-01

    Background: Renal tubulointerstitial fibrosis is the pathological hallmark of chronic kidney disease (CKD). Currently, inhibitors of the renin–angiotensin system (RAS) remain the sole therapy in human displaying antifibrotic properties. Further antifibrotic molecules are needed. We have recently reported that the delayed blockade of the bradykinin B1 receptor (B1R) reduced the development of fibrosis in two animal models of renal fibrosis. The usefulness of new drugs also resides in outperforming the gold standards and eventually being additive or complementary to existing therapies. Methods: In this study we compared the efficacy of a B1R antagonist (B1Ra) with that of an angiotensin type 1 receptor antagonist (AT1a) in the unilateral ureteral obstruction (UUO) model of renal fibrosis and determined whether bi-therapy presented higher efficacy than any of the drugs alone. Results: B1R antagonism was as efficient as the gold-standard AT1a treatment. However, bitherapy did not improve the antifibrotic effects at the protein level. We sought for the reason of the absence of this additive effect by studying the expression of a panel of genes involved in the fibrotic process. Interestingly, at the molecular level the different drugs targeted different players of fibrosis that, however, in this severe model did not result in improved reduction of fibrosis at the protein level. Conclusions: As the B1R is induced specifically in the diseased organ and thus potentially displays low side effects it might be an interesting alternative in cases of poor tolerability to RAS inhibitors. PMID:25698969

  18. Nutrient shielding in clusters of cells

    Science.gov (United States)

    Lavrentovich, Maxim O.; Koschwanez, John H.; Nelson, David R.

    2013-06-01

    Cellular nutrient consumption is influenced by both the nutrient uptake kinetics of an individual cell and the cells' spatial arrangement. Large cell clusters or colonies have inhibited growth at the cluster's center due to the shielding of nutrients by the cells closer to the surface. We develop an effective medium theory that predicts a thickness ℓ of the outer shell of cells in the cluster that receives enough nutrient to grow. The cells are treated as partially absorbing identical spherical nutrient sinks, and we identify a dimensionless parameter ν that characterizes the absorption strength of each cell. The parameter ν can vary over many orders of magnitude among different cell types, ranging from bacteria and yeast to human tissue. The thickness ℓ decreases with increasing ν, increasing cell volume fraction ϕ, and decreasing ambient nutrient concentration ψ∞. The theoretical results are compared with numerical simulations and experiments. In the latter studies, colonies of budding yeast, Saccharomyces cerevisiae, are grown on glucose media and imaged under a confocal microscope. We measure the growth inside the colonies via a fluorescent protein reporter and compare the experimental and theoretical results for the thickness ℓ.

  19. Limiting nutrient emission from a cut rose closed system by high-flux irrigation and low nutrient concentrations?

    NARCIS (Netherlands)

    Baas, R.; Berg, van der D.

    2004-01-01

    A two-year project was aimed at decreasing nutrient emission from closed nutrient systems by using high irrigation rates in order to allow lower EC levels in the presence of accumulated Na and Cl. Experimental variables were growing media, irrigation frequencies, EC and NaCl concentrations for cut

  20. Additive Manufacturing of Single-Crystal Superalloy CMSX-4 Through Scanning Laser Epitaxy: Computational Modeling, Experimental Process Development, and Process Parameter Optimization

    Science.gov (United States)

    Basak, Amrita; Acharya, Ranadip; Das, Suman

    2016-08-01

    This paper focuses on additive manufacturing (AM) of single-crystal (SX) nickel-based superalloy CMSX-4 through scanning laser epitaxy (SLE). SLE, a powder bed fusion-based AM process was explored for the purpose of producing crack-free, dense deposits of CMSX-4 on top of similar chemistry investment-cast substrates. Optical microscopy and scanning electron microscopy (SEM) investigations revealed the presence of dendritic microstructures that consisted of fine γ' precipitates within the γ matrix in the deposit region. Computational fluid dynamics (CFD)-based process modeling, statistical design of experiments (DoE), and microstructural characterization techniques were combined to produce metallurgically bonded single-crystal deposits of more than 500 μm height in a single pass along the entire length of the substrate. A customized quantitative metallography based image analysis technique was employed for automatic extraction of various deposit quality metrics from the digital cross-sectional micrographs. The processing parameters were varied, and optimal processing windows were identified to obtain good quality deposits. The results reported here represent one of the few successes obtained in producing single-crystal epitaxial deposits through a powder bed fusion-based metal AM process and thus demonstrate the potential of SLE to repair and manufacture single-crystal hot section components of gas turbine systems from nickel-based superalloy powders.

  1. An Experimental Investigation on the Effect of Addition of Ternary Blend on the Mix Design Characteristics of High Strength Concrete using Steel Fibre

    Science.gov (United States)

    Sinha, Deepa A., Dr; Verma, A. K., Dr

    2017-08-01

    This paper presents the results of M60 grade of concrete. M60 grade of concrete is achieved by maximum density technique. Concrete is brittle and weak in tension and develops cracks during curing and due to thermal expansion / contraction over a period ot time. Thus the effect of addition of 1% steel fibre is studied. For ages, concrete has been one of the widely used materials for construction. When cement is manufactured, every one ton of cement produces around one ton of carbon dioxide leading to global warming and also as natural resources are finishing, so use of supplementary cementitious material like alccofine and flyash is used as partial replacement of cement is considered. The effect of binary and ternary blend on the strength characteristics is studied. The results indicate that the concrete made with alccofine and flyash generally show excellent fresh and hardened properties. The ternary system that is Portland cement-fly ash-Alccofine concrete was found to increase the strength of concrete when compared to concrete made with Portland cement or even from Portland cement and fly ash.

  2. Mitigating cyanobacterial harmful algal blooms in aquatic ecosystems impacted by climate change and anthropogenic nutrients.

    Science.gov (United States)

    Paerl, Hans W; Gardner, Wayne S; Havens, Karl E; Joyner, Alan R; McCarthy, Mark J; Newell, Silvia E; Qin, Boqiang; Scott, J Thad

    2016-04-01

    Mitigating the global expansion of cyanobacterial harmful blooms (CyanoHABs) is a major challenge facing researchers and resource managers. A variety of traditional (e.g., nutrient load reduction) and experimental (e.g., artificial mixing and flushing, omnivorous fish removal) approaches have been used to reduce bloom occurrences. Managers now face the additional effects of climate change on watershed hydrologic and nutrient loading dynamics, lake and estuary temperature, mixing regime, internal nutrient dynamics, and other factors. Those changes favor CyanoHABs over other phytoplankton and could influence the efficacy of control measures. Virtually all mitigation strategies are influenced by climate changes, which may require setting new nutrient input reduction targets and establishing nutrient-bloom thresholds for impacted waters. Physical-forcing mitigation techniques, such as flushing and artificial mixing, will need adjustments to deal with the ramifications of climate change. Here, we examine the suite of current mitigation strategies and the potential options for adapting and optimizing them in a world facing increasing human population pressure and climate change. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Biofortification of crops with nutrients: factors affecting utilization and storage.

    Science.gov (United States)

    Díaz-Gómez, Joana; Twyman, Richard M; Zhu, Changfu; Farré, Gemma; Serrano, José Ce; Portero-Otin, Manuel; Muñoz, Pilar; Sandmann, Gerhard; Capell, Teresa; Christou, Paul

    2017-04-01

    Biofortification is an effective and economical method to improve the micronutrient content of crops, particularly staples that sustain human populations in developing countries. Whereas conventional fortification requires artificial additives, biofortification involves the synthesis or accumulation of nutrients by plants at source. Little is known about the relative merits of biofortification and artificial fortification in terms of nutrient bioaccessibility and bioavailability, and much depends on the biochemical nature of the nutrient, which can promote or delay uptake, and determine how efficiently different nutrients are transported through the blood, stored, and utilized. Data from the first plants biofortified with minerals and vitamins provide evidence that the way in which nutrients are presented can affect how they are processed and utilized in the human body. The latest studies on the effects of the food matrix, processing and storage on nutrient transfer from biofortified crops are reviewed, as well as current knowledge about nutrient absorption and utilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Electro-acupuncture reduces the need for additional anesthetics in experimental studies Eletroacupuntura reduz a necessidade de doses adicionais de anestésicos em estudos experimentais

    Directory of Open Access Journals (Sweden)

    Agamenon Honório Silva

    2010-08-01

    Full Text Available PURPOSE: To evaluate the possible beneficial effects of electro-acupuncture in rats subjected to ketamine/xylazine (KX intra-peritoneal (i.p. anesthesia. METHODS: Forty-eight male Wistar rats were distributed in four equal groups. All rats received i.p. injections of ketamine (90 mg/kg +xylazine (10 mg/kg anesthesia. Basal values group (control rats (BV received no additional treatment. The equivalent of the human right ST36 (Zusanli and CV-12(Zhongwan acupoints were chosen for needling and electrical stimulation. AC rats were needled with sterilized disposable stainless steel needles at right ST36 and CV12 acupoints; needles were retained for 30 minutes. EAC10 rats, after needle insertion as described, had electrodes connected to both needles and to an electro stimulator model NKL EL-608; pulsed square waves, 10 Hz, 10 mA, was applied for 30 minutes. EAC100 rats were submitted to EA as described. However, a greater frequency (100 Hz was used. RESULTS: Thirty-seven rats remained under adequate anesthetic level during the experiment. However, maintenance anesthesia was required by 11 rats. Need for additional anesthesia decreased to 9.1% in EAC100 rats compared to BV (36.3%. CONCLUSION: Both the AC and the EAC10/100 prolong the anesthetic effect of the combination Ketamine-xylazine in rats, allowing longer duration of anesthesia with a lower dose of anesthetic, thereby reducing the occurrence of complications.OBJETIVO: Avaliar os possíveis efeitos benéficos da eletroacupuntura em ratos submetidos à anestesia intraperitoneal (i.p. com ketamina / xilazina. MÉTODOS: Quarenta e oito ratos Wistar foram randomizados em quatro grupos iguais. Todos os ratos receberam injeções i.p. de ketamina (90 mg / kg + xilazina (10 mg / kg. Os ratos do grupo Valores Basais (controle - BV não receberam nenhum tratamento adicional. Os acupontos equivalentes aos humanos E-36 (Zusanli e VC-12 (Zhongwan foram escolhidos para inserção de agulhas e estimulação el

  5. Evaluation of nutrient addition to diesel biodegradation in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-07-20

    Jul 20, 2009 ... hazardous chemicals. The cargo was only being removed in February 2004, demonstrating how time-consuming a clean-up operation can be. As an alternative to physicochemical clean-up methods resulting in negative consequences, bioremediation offers an appealing treatment technology for petroleum ...

  6. Nutrient synchrony in preruminant calves

    NARCIS (Netherlands)

    Borne, van den J.J.G.C.

    2006-01-01

    In animal nutrition, the nutrient composition of the daily feed supply is composed to match the nutrient requirements for the desired performance. The time of nutrient availability within a day is usually considered not to affect the fate of nutrients. The aim of this thesis was to evaluate effects

  7. Nutrient acquisition by mycobacteria.

    Science.gov (United States)

    Niederweis, Michael

    2008-03-01

    The growth and nutritional requirements of mycobacteria have been intensively studied since the discovery of Mycobacterium tuberculosis more than a century ago. However, the identity of many transporters for essential nutrients of M. tuberculosis and other mycobacteria is still unknown despite a wealth of genomic data and the availability of sophisticated genetic tools. Recently, considerable progress has been made in recognizing that two lipid permeability barriers have to be overcome in order for a nutrient molecule to reach the cytoplasm of mycobacteria. Uptake processes are discussed by comparing M. tuberculosis with Mycobacterium smegmatis. For example, M. tuberculosis has only five recognizable carbohydrate transporters in the inner membrane, while M. smegmatis has 28 such transporters at its disposal. The specificities of inner-membrane transporters for sulfate, phosphate and some amino acids have been determined. Outer-membrane channel proteins in both organisms are thought to contribute to nutrient uptake. In particular, the Msp porins have been shown to be required for uptake of carbohydrates, amino acids and phosphate by M. smegmatis. The set of porins also appears to be different for M. tuberculosis and M. smegmatis. These differences likely reflect the lifestyles of these mycobacteria and the availability of nutrients in their natural habitats: the soil and the human body. The comprehensive identification and the biochemical and structural characterization of the nutrient transporters of M. tuberculosis will not only promote our understanding of the physiology of this important human pathogen, but might also be exploited to improve tuberculosis chemotherapy.

  8. Nutrient sensing and signaling in the yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Conrad, Michaela; Schothorst, Joep; Kankipati, Harish Nag; Van Zeebroeck, Griet; Rubio-Texeira, Marta; Thevelein, Johan M

    2014-01-01

    The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein-coupled receptor system, and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing target of rapamycin pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance, and ribosomal gene expression, are controlled by the presence of multiple nutrients. The protein kinase A signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing, and the identity of the nutrient sensors controlling cellular growth. PMID:24483210

  9. Adição de inulina em géis de amido e leite utilizando planejamento experimental de misturas Addition of inulin to starch and milk gels using an experimental mixture design

    Directory of Open Access Journals (Sweden)

    Luciana Pereira Lobato

    2012-06-01

    Full Text Available O objetivo deste estudo foi investigar o efeito combinado de inulina, amido e leite nas características texturais de géis e de propriedades de pastas empregando o planejamento experimental de misturas. Foram avaliados o perfil viscoamilográfico e a firmeza dos géis. Em todos os parâmetros avaliados, os modelos ajustados mostraram-se influenciados pela presença de inulina, amido e leite, assim como de algumas interações desses ingredientes. A viscosidade máxima e a viscosidade final foram influenciadas positivamente pela concentração de amido e negativamente pelas interações deste com leite e com inulina. A firmeza dos géis aumentou com o aumento do teor de amido, mas a interação amido-inulina foi antagônica, contribuindo para diminuir essa característica. O efeito da interação entre amido e inulina pode ser explicado pelo fato de que a inulina possui maior afinidade pela água, em relação ao amido, ou, ainda, por agir como diluente, fazendo com que haja menor contato entre os grânulos e/ou cadeias de amido. A partir dos resultados encontrados neste estudo, verifica-se que a inclusão da inulina em sistemas amido-leite pode influenciar nas características texturais e de viscosidade, possivelmente refletindo-se nas características sensoriais. Com isso, a avaliação das interações com outros ingredientes da formulação torna-se essencial.The objective of this work was to investigate the combined effect of milk, starch and inulin on the textural characteristics of gels and on the pasting properties, using an experimental mixture design. Gel firmness and the amylographic profile were evaluated. For all the parameters evaluated, the fitted models were shown to be influenced by the presence of inulin, starch and milk, as also some of the interactions between the ingredients. The maximum viscosity and final viscosity were positively influenced by the starch concentration and negatively by interactions between the starch and

  10. Nutrients that limit growth in the ocean.

    Science.gov (United States)

    Bristow, Laura A; Mohr, Wiebke; Ahmerkamp, Soeren; Kuypers, Marcel M M

    2017-06-05

    Phytoplankton form the basis of the marine food web and are responsible for approximately half of global carbon dioxide (CO2) fixation (∼ 50 Pg of carbon per year). Thus, these microscopic, photosynthetic organisms are vital in controlling the atmospheric CO2 concentration and Earth's climate. Phytoplankton are dependent on sunlight and their CO2-fixation activity is therefore restricted to the upper, sunlit surface ocean (that is, the euphotic zone). CO2 usually does not limit phytoplankton growth due to its high concentration in seawater. However, the vast majority of oceanic surface waters are depleted in inorganic nitrogen, phosphorus, iron and/or silica; nutrients that limit primary production in the ocean (Figure 1). Phytoplankton growth is mainly supported by either the recycling of nutrients or by reintroduction of nutrients from deeper waters by mixing. A small percentage of primary production, though, is fueled by 'external' or 'new' nutrients and it is these nutrients that determine the amount of carbon that can be sequestered long term in the deep ocean. For most nutrients such as phosphorus, iron, and silica, the external supply is limited to atmospheric deposition and/or coastal and riverine inputs, whereas their main sink is the sedimentation of particulate matter. Nitrogen, however, has an additional, biological source, the fixation of N2 gas, as well as biological sinks via the processes of denitrification and anammox. Despite the comparatively small contributions to the overall turnover of nutrients in the ocean, it is these biological processes that determine the ocean's capacity to sequester CO2 from the atmosphere on time scales of ocean circulation (∼ 1000 years). This primer will highlight shifts in the traditional paradigms of nutrient limitation in the ocean, with a focus on the uniqueness of the nitrogen cycling and its biological sources and sinks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Binaural additivity of loudness

    NARCIS (Netherlands)

    Levelt, W.J.M.; Riemersma, J.B.; Bunt, A.A.

    1972-01-01

    A definition of binaural additivity is given in terms of the theory of simultaneous conjoint measurement. Additivity is then tested and verified by a conjoint measurement procedure. Methods for deriving psychophysical scales from such procedures are discussed, and the experimental scales are

  12. Convergence of detrital stoichiometry predicts thresholds of nutrient-stimulated breakdown in streams.

    Science.gov (United States)

    Manning, David W P; Rosemond, Amy D; Gulis, Vladislav; Benstead, Jonathan P; Kominoski, John S; Maerz, John C

    2016-09-01

    Nutrient enrichment of detritus-based streams increases detrital resource quality for consumers and stimulates breakdown rates of particulate organic carbon (C). The relative importance of dissolved inorganic nitrogen (N) vs. phosphorus (P) for detrital quality and their effects on microbial- vs. detritivore-mediated detrital breakdown are poorly understood. We tested effects of experimental N and P additions on detrital stoichiometry (C:N, C:P) and total and microbial breakdown (i.e., with and without detritivorous shredders, respectively) of five detritus types (four leaf litter species and wood) with different initial C : nutrient content. We enriched five headwater streams continuously for two years at different relative availabilities of N and P and compared breakdown rates and detrital stoichiometry to pretreatment conditions. Total breakdown rates increased with nutrient enrichment and were predicted by altered detrital stoichiometry. Streamwater N and P, fungal biomass, and their interactions affected stoichiometry of detritus. Streamwater N and P decreased detrital C:N, whereas streamwater P had stronger negative effects on detrital C:P. Nutrient addition and fungal biomass reduced C:N by 70% and C:P by 83% on average after conditioning, compared to only 26% for C:N and 10% for C:P under pretreatment conditions. Detritus with lowest initial nutrient content changed the most and had greatest increases in total breakdown rates. Detrital stoichiometry was reduced and differences among detritus types were homogenized by nutrient enrichment. With enrichment, detrital nutrient content approached detritivore nutritional requirements and stimulated greater detritivore vs. microbial litter breakdown. We used breakpoint regression to estimate values of detrital stoichiometry that can potentially be used to indicate elevated breakdown rates. Breakpoint ratios for total breakdown were 41 (C:N) and 1518 (C:P), coinciding with total breakdown rates that were ~1.9

  13. Arbuscular mycorrhizal fungal species differ in their effect on nutrient leaching

    NARCIS (Netherlands)

    Köhl, Luise; van der Heijden, Marcel G A

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi have been shown to play a crucial role in nutrient cycling and can reduce nutrient losses after rain induced leaching events. It is still unclear whether nutrient leaching losses vary depending on the AM fungal taxa that are present in soil. Using experimental

  14. Exogenous fibrolytic enzymes to unlock nutrients: Histological ...

    African Journals Online (AJOL)

    Exogenous fibrolytic enzymes to unlock nutrients: Histological investigation of its effects on fibre degradation in ruminants. ... There is a need for a better understanding of the mode-of-action of exogenous fibrolytic enzymes (EFE) used as additives in ruminant feeds. ... Keywords: Fibre digestion, histology, in vitro digestion ...

  15. The role of nutrient solution composition on the uptake of nutrients ...

    African Journals Online (AJOL)

    for growth measurements, postharvest evaluations as well as nutrient analysis prior to harvest so as to eliminate bias. The remaining unlabelled, marketable plants were to be used in the vase-life studies. Treatments. Two trials were carried out in a climate-controlled glasshouse at Welgevallen Experimental Farm, University.

  16. Hydrologic and biologic influences on stream network nutrient concentrations: Interactions of hydrologic turnover and concentration-dependent nutrient uptake

    Science.gov (United States)

    Mallard, John; McGlynn, Brian; Covino, Tim

    2016-04-01

    Stream networks lie in a crucial landscape position between terrestrial ecosystems and downstream water bodies. As such, whether inferring terrestrial watershed processes from watershed outlet nutrient signals or predicting the effect of observed terrestrial processes on stream nutrient signals, it is requisite to understand how stream networks can modulate terrestrial nutrient inputs. To date integrated understanding and modeling of physical and biological influences on nutrient concentrations at the stream network scale have been limited. However, watershed scale groundwater - surface water exchange (hydrologic turnover), concentration-variable biological uptake, and the interaction between the two can strongly modify stream water nutrient concentrations. Stream water and associated nutrients are lost to and replaced from groundwater with distinct nutrient concentrations while in-stream nutrients can also be retained by biological processes at rates that vary with concentration. We developed an empirically based network scale model to simulate the interaction between hydrologic turnover and concentration-dependent nutrient uptake across stream networks. Exchange and uptake parameters were measured using conservative and nutrient tracer addition experiments in the Bull Trout Watershed, central Idaho. We found that the interaction of hydrologic turnover and concentration-dependent uptake combined to modify and subsequently stabilize in-stream concentrations, with specific concentrations dependent on the magnitude of hydrologic turnover, groundwater concentrations, and the shape of nutrient uptake kinetic curves. We additionally found that by varying these physical and biological parameters within measured ranges we were able to generate a spectrum of stream network concentration distributions representing a continuum of shifting magnitudes of physical and biological influences on in-stream concentrations. These findings elucidate the important and variable role of

  17. Impact of organic nutrient load on biomass accumulation, feed channel pressure drop increase and permeate flux decline in membrane systems

    KAUST Repository

    Bucs, Szilard

    2014-12-01

    The influence of organic nutrient load on biomass accumulation (biofouling) and pressure drop development in membrane filtration systems was investigated. Nutrient load is the product of nutrient concentration and linear flow velocity. Biofouling - excessive growth of microbial biomass in membrane systems - hampers membrane performance. The influence of biodegradable organic nutrient load on biofouling was investigated at varying (i) crossflow velocity, (ii) nutrient concentration, (iii) shear, and (iv) feed spacer thickness. Experimental studies were performed with membrane fouling simulators (MFSs) containing a reverse osmosis (RO) membrane and a 31 mil thick feed spacer, commonly applied in practice in RO and nanofiltration (NF) spiral-wound membrane modules. Numerical modeling studies were done with identical feed spacer geometry differing in thickness (28, 31 and 34 mil). Additionally, experiments were done applying a forward osmosis (FO) membrane with varying spacer thickness (28, 31 and 34 mil), addressing the permeate flux decline and biofilm development. Assessed were the development of feed channel pressure drop (MFS studies), permeate flux (FO studies) and accumulated biomass amount measured by adenosine triphosphate (ATP) and total organic carbon (TOC).Our studies showed that the organic nutrient load determined the accumulated amount of biomass. The same amount of accumulated biomass was found at constant nutrient load irrespective of linear flow velocity, shear, and/or feed spacer thickness. The impact of the same amount of accumulated biomass on feed channel pressure drop and permeate flux was influenced by membrane process design and operational conditions. Reducing the nutrient load by pretreatment slowed-down the biofilm formation. The impact of accumulated biomass on membrane performance was reduced by applying a lower crossflow velocity and/or a thicker and/or a modified geometry feed spacer. The results indicate that cleanings can be delayed

  18. Accumulative capabilities of essential nutrient elements in organs of ...

    African Journals Online (AJOL)

    use

    2011-11-23

    Nov 23, 2011 ... E-mail: Mashelap@ul.ac.za. The content of essential nutrient elements in a given organ depends on the organ's accumulative capabilities. (ACs) and the interactions of the nutrient elements in that organ (Salisbury and Ross, 1992). Information on the. ACs of organs is important since in addition to providing.

  19. Plant Nutrient Testing and Analysis in Forest and Conservation Nurseries

    Science.gov (United States)

    Thomas D. Landis; Diane L. Haase; R. Kasten Dumroese

    2005-01-01

    Supplying mineral nutrients at the proper rate and in the proper balance has a major effect on seedling growth rate but, more importantly, on seedling quality. In addition, mounting concerns about fertilizer pollution are increasing awareness of the benefits of precision fertilization. Because they reflect actual mineral nutrient uptake, plant tissue tests are the best...

  20. Noninvasive detection of plant nutrient stress using fiber optic spectrophotometry

    Science.gov (United States)

    Chen, Jun-Wei; Asundi, Anand K.; Liew, Oi Wah; Boey, William S. L.

    2001-05-01

    In a previous paper, we described the use of fiber optic spectrophotometry as a non-destructive and sensitive method to detect early symptoms of plant nutrient deficiency. We report further developments of our work on Brassica chinensis var parachinensis (Bailey) showing reproducibility of our data collected at a different seasonal period. Plants at the mid-log growth phase were subjected to nutrient stress by transferring them to nitrate- and calcium- deficient nutrient solution in a standing aerated hydroponic system. After tracking changes in leaf reflectance by FOSpectr for nine days, the plants were returned to complete nutrient solution and their recovery was monitored for a further nine days. The responses of nutrient stressed plants were compared with those grown under complete nutrient solution over the 18-day trial period. We also compared the sensitivity of FOSpectr detection against plant growth measurements vis-a-vis average leaf number and leaf width and show that the former method gave an indication of nutrient stress much earlier than the latter. In addition, this work indicated that while normal and nutrient-stressed plants could not be distinguished within the first 7 days by tracking plant growth indicators, stressed plants did show a clear decline in average leaf number and leaf width in later stages of growth even after the plants were returned to complete nutrient solution. The results further reinforce the need for early detection of nutrient stress, as late remedial action could not reverse the loss in plant growth in later stages of plant development.

  1. Nutrient release, recovery and removal from waste sludge of a biological nutrient removal system.

    Science.gov (United States)

    Wang, Yi; Zheng, Shu-Jian; Pei, Li-Ying; Ke, Li; Peng, Dang-Cong; Xia, Si-Qing

    2014-01-01

    The uncontrolled release of nutrients from waste sludge results in nitrogen and phosphorus overloading in wastewater treatment plants when supernatant is returned to the inlet. A controlled release, recovery and removal of nutrient from the waste sludge of a Biological Nutrient Removal system (BNR) are investigated. Results showed that the supernatant was of high mineral salt, high electrical conductivity and poor biodegradability, in addition to high nitrogen and phosphorus concentrations after the waste sludge was hydrolysed through sodium dodecyl sulphate addition. Subsequently, over 91.8% of phosphorus and 10.5% of nitrogen in the supernatants were extracted by the crystallization method under the conditions of 9.5 pH and 400 rpm. The precipitate was mainly struvite according to X-ray diffraction and morphological examination. A multistage anoxic-oxic Moving Bed Biofilm Reactor (MBBR) was then adopted to remove the residual carbon, nitrogen and phosphorus in the supernatant. The MBBR exhibited good performance in simultaneously removing carbon, nitrogen and phosphorus under a short aeration time, which accounted for 31.25% of a cycle. Fluorescence in situ hybridization analysis demonstrated that nitrifiers presented mainly in floc, although higher extracellular polymeric substance content, especially DNA, appeared in the biofilm. Thus, a combination of hydrolysis and precipitation, followed by the MBBR, can complete the nutrient release from the waste sludge of a BNR system, recovers nutrients from the hydrolysed liquor and removes nutrients from leftovers effectively.

  2. Potlining Additives

    Energy Technology Data Exchange (ETDEWEB)

    Rudolf Keller

    2004-08-10

    In this project, a concept to improve the performance of aluminum production cells by introducing potlining additives was examined and tested. Boron oxide was added to cathode blocks, and titanium was dissolved in the metal pool; this resulted in the formation of titanium diboride and caused the molten aluminum to wet the carbonaceous cathode surface. Such wetting reportedly leads to operational improvements and extended cell life. In addition, boron oxide suppresses cyanide formation. This final report presents and discusses the results of this project. Substantial economic benefits for the practical implementation of the technology are projected, especially for modern cells with graphitized blocks. For example, with an energy savings of about 5% and an increase in pot life from 1500 to 2500 days, a cost savings of $ 0.023 per pound of aluminum produced is projected for a 200 kA pot.

  3. Leaf trait response to nutrients and herbivore exclusion across a globally replicated grassland experiment

    Science.gov (United States)

    Firn, Jennifer

    2017-04-01

    climatic conditions and subjected to the same set of experimental treatments. The main aim of this paper is to quantify how changes in nutrient availability (NPK fertilizer application in all factorial combinations) and grazing alter the functional leaf traits of species over the short-term. Our results show that SLA varies at a site level ( 75% of the variation in SLA in response to treatments were explained at the site level). Leaf nitrogen (%), leaf phosphorous and leaf potassium varied significantly depending on treatment and where respective nutrients were added. Variation in leaf potassium showed the highest variation between species ( 60%). Overall, we should that leaf nutrient levels are a stronger indicator of functional response to nutrients addition across sites than specific leaf area. These findings have important implications for how leaf functional traits are used to infer responses to pervasive environmental change within and across grassland sites.

  4. Use of phytogenic products as feed additives for swine and poultry.

    Science.gov (United States)

    Windisch, W; Schedle, K; Plitzner, C; Kroismayr, A

    2008-04-01

    This article summarizes the experimental knowledge on efficacy, possible modes of action, and aspects of application of phytogenic products as feed additives for swine and poultry. Phytogenic feed additives comprise a wide variety of herbs, spices, and products derived thereof, and are mainly essential oils. The assumption that phytogenic compounds might improve the palatability of feed has not yet been confirmed by choice-feeding studies. Although numerous studies have demonstrated antioxidative and antimicrobial efficacy in vitro, respective experimental in vivo evidence is still quite limited. The same applies to the supposition that phytogenic compounds may specifically enhance activities of digestive enzymes and nutrient absorption. Nevertheless, a limited number of experimental comparisons of phytogenic feed additives with antibiotics and organic acids have suggested similar effects on the gut, such as reduced bacterial colony counts, fewer fermentation products (including ammonia and biogenic amines), less activity of the gut-associated lymphatic system, and a greater prececal nutrient digestion, probably reflecting an overall improved gut equilibrium. In addition, some phytogenic compounds seem to promote intestinal mucus production. Such effects may explain a considerable number of practical studies with swine and poultry reporting improved production performance after providing phytogenic feed additives. In total, available evidence indicates that phytogenic feed additives may add to the set of nonantibiotic growth promoters for use in livestock, such as organic acids and probiotics. However, a systematic approach toward the efficacy and safety of phytogenic compounds used as feed additives for swine and poultry is still missing.

  5. Nutrient availability as a control of the abundance and activities of deep subsurface microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Ghiorse, W.C.

    1992-01-01

    The focus of our research is to determine whether the availability of major nutrients (C, N, P) control the abundance, distribution, and activity of heterotrophic microorganisms in subsurface sediments. Specifically we have developed and are testing a microcosm system using subsurface sediment samples from a DOE site. We are using this system to conduct a preliminary nutrient enrichment experiments. The flow-through microcosm system simulates conditions in natural aquifers and can be regulated with respect to water flow rate, temperature, oxygen concentration, and nutrient concentration. Furthermore, the system cam be run aseptically, excluding exogenous bacteria from test cores. In our preliminary nutrient enrichment experiment, we collected deep vadose sediment from the Savannah River Site and pumped sterilized well water from sampling area through microcosms that were filled with this sediment. Experimental treatments included the flow-through of this water amen with different combinations of nutrients (+N+P, +C, +N+P+C) or no additional nutrients. We found that asepsis was maintained for the entire 30 day experiment. We also found that microbial abundance, biomass, and activity increased in several microcosms in response to the flow through of the well water, which was rich in nitrate. This response, however, was variable among both microcosms containing intact sediments and microcosms containing intact sediment core sections. No significant treatment responses were observed, but each microcosm that had an increase in microbial growth also immobilized N from the well water. We infer that water and N availability, and water table fluctuations strongly influence microbial growth and activity in the deep vadose.

  6. Nutrients in the nexus

    Science.gov (United States)

    Davidson, Eric A.; Niphong, Rachel; Ferguson, Richard B.; Palm, Cheryl; Osmond, Deanna L.; Baron, Jill S.

    2016-01-01

    Synthetic nitrogen (N) fertilizer has enabled modern agriculture to greatly improve human nutrition during the twentieth century, but it has also created unintended human health and environmental pollution challenges for the twenty-first century. Averaged globally, about half of the fertilizer-N applied to farms is removed with the crops, while the other half remains in the soil or is lost from farmers’ fields, resulting in water and air pollution. As human population continues to grow and food security improves in the developing world, the dual development goals of producing more nutritious food with low pollution will require both technological and socio-economic innovations in agriculture. Two case studies presented here, one in sub-Saharan Africa and the other in Midwestern United States, demonstrate how management of nutrients, water, and energy is inextricably linked in both small-scale and large-scale food production, and that science-based solutions to improve the efficiency of nutrient use can optimize food production while minimizing pollution. To achieve the needed large increases in nutrient use efficiency, however, technological developments must be accompanied by policies that recognize the complex economic and social factors affecting farmer decision-making and national policy priorities. Farmers need access to affordable nutrient supplies and support information, and the costs of improving efficiencies and avoiding pollution may need to be shared by society through innovative policies. Success will require interdisciplinary partnerships across public and private sectors, including farmers, private sector crop advisors, commodity supply chains, government agencies, university research and extension, and consumers.

  7. Nutrients affecting brain composition and behavior

    Science.gov (United States)

    Wurtman, R. J.

    1987-01-01

    This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

  8. Effect of imbalanced nutrients and immigration on Prymnesium parvum community dominance and toxicity: Results from in-lake microcosm experiments

    Science.gov (United States)

    Errera, R.M.; Roelke, D.L.; Kiesling, R.L.; Brooks, B.W.; Grover, J.P.; Schwierzke, L.; Urena-Boeck, F.; Baker, J.W.; Pinckney, J.L.

    2008-01-01

    Prymnesium parvum, a haptophyte species, forms harmful blooms, including those that have caused severe fish kills in Texas, USA, over the past 6 yr. We studied P. parvum dynamics using in situ microcosm experiments at Lake Possum Kingdom, Texas, during 3 seasons (fall 2004, winter and spring 2005). Experimental treatments included full and partial nutrient enrichment (encompassing nitrogen [N] and phosphorus [P] deficient treatments), P. parvum immigration and combinations of these factors. In the control and N and P deficient treatments, P. parvum populations dominated the community, but only in the N deficient treatments did P. parvum experience a significant growth in the population. In contrast, when nutrients were not limiting, P. parvum tended to lose its competitive edge to other taxa such as chlorophytes, euglenophytes and diatoms, which then dominated the community. Population growth of P. parvum was also stimulated through immigration, but only during the winter experiment, a period of the year when bloom initiation is common. This finding suggests that movement into the water column may be an important process leading to P. parvum bloom initiation. Toxicity of P. parvum to fish was also affected by the nutrient changes: during conditions of no nutrient addition P. parvum was most toxic; intermediate toxicity was observed under N and P deficient conditions, and full nutrient enrichments resulted in nearly non-toxic conditions. ?? Inter-Research 2008.

  9. Contribution of complementary food nutrients to estimated total nutrient intakes for rural Guatemalan infants in the second semester of life.

    Science.gov (United States)

    Campos, Raquel; Hernandez, Liza; Soto-Mendez, Maria Jose; Vossenaar, Marieke; Solomons, Noel W

    2010-01-01

    In developing countries, complementary foods are often introduced earlier or later than appropriate and the quality is frequently insufficient, particularly in rural areas where complementary foods have traditionally been based on starchy gruels. Adequate intakes of a number of nutrients are recognized to be problematic in traditional complementary feeding regimens in developing societies. To determine the contribution of the complementary feeding nutrients to the estimated total nutrient intake in Guatemalan infants. Three non-consecutive 24-hr recalls were collected from a convenience sample of mothers of 64 infants, aged 6-12 month on enrolment, in the rural Guatemalan highland village of Santo Domingo Xenacoj. Additional information on early introduction of pre- and post-lacteal feeds and on first foods and beverages was included. Human milk intakes were estimated by a model based on assumptions regarding satisfaction of weight-based daily energy needs by the combined diet. The 2004 WHO/FAO recommended nutrient intakes were used as the standard for adequate nutrient consumption. We observed that exclusive breastfeeding up to 6 month is rare. Mean nutrient intakes and densities were above recommended intakes for all nutrients examined, except calcium, iron and zinc. Intakes of most nutrients were greater from the complementary feeding component of the diet. Vitamin A intake was excessive due to consumption of fortified sugar. We conclude that intakes of most micronutrients were near recommendation levels, unusual within the complementary feeding experience in scientific literature. Calcium, iron and zinc were identified as "problem nutrients" as persistently reported in developing countries.

  10. Export of nutrients from the Arctic Ocean

    Science.gov (United States)

    Torres-Valdés, Sinhué; Tsubouchi, Takamasa; Bacon, Sheldon; Naveira-Garabato, Alberto C.; Sanders, Richards; McLaughlin, Fiona A.; Petrie, Brian; Kattner, Gerhard; Azetsu-Scott, Kumiko; Whitledge, Terry E.

    2013-04-01

    study provides the first physically based mass-balanced transport estimates of dissolved inorganic nutrients (nitrate, phosphate, and silicate) for the Arctic Ocean. Using an inverse model-generated velocity field in combination with a quasi-synoptic assemblage of hydrographic and hydrochemical data, we quantify nutrient transports across the main Arctic Ocean gateways: Davis Strait, Fram Strait, the Barents Sea Opening (BSO), and Bering Strait. We found that the major exports of all three nutrients occur via Davis Strait. Transports associated with the East Greenland Current are almost balanced by transports associated with the West Spitsbergen Current. The most important imports of nitrate and phosphate to the Arctic occur via the BSO, and the most important import of silicate occurs via Bering Strait. Oceanic budgets show that statistically robust net silicate and phosphate exports exist, while the net nitrate flux is zero, within the uncertainty limits. The Arctic Ocean is a net exporter of silicate (-15.7 ± 3.2 kmol s-1) and phosphate (-1.0 ± 0.3 kmol s-1; net ± 1 standard error) to the North Atlantic. The export of excess phosphate (relative to nitrate) from the Arctic, calculated at -1.1 ± 0.3 kmol s-1, is almost twice as large as previously estimated. Net transports of silicate and phosphate from the Arctic Ocean provide 12% and 90%, respectively, of the net southward fluxes estimated at 47°N in the North Atlantic. Additional sources of nutrients that may offset nutrient imbalances are explored, and the relevance and the pathway of nutrient transports to the North Atlantic are discussed.

  11. Nutrients, Foods, and Colorectal Cancer Prevention

    Science.gov (United States)

    Song, Mingyang; Garrett, Wendy S.; Chan, Andrew T.

    2015-01-01

    Diet has an important role in the development of colorectal cancer. In the past few decades, findings from extensive epidemiologic and experimental investigation have linked consumption of several foods and nutrients to the risk of colorectal neoplasia. Calcium, fiber, milk, and whole grain have been associated with a lower risk of colorectal cancer, and red meat and processed meat with an increased risk. There is substantial evidence for the potential chemopreventive effects of vitamin D, folate, fruits and vegetables. Nutrients and foods may also interact, as a dietary pattern, to influence colorectal cancer risk. Diet likely influences colorectal carcinogenesis through several interacting mechanisms. These include the direct effects on immune responsiveness and inflammation, and the indirect effects of over-nutrition and obesity—risk factors for colorectal cancer. Emerging evidence also implicates the gut microbiota as an important effector in the relationship between diet and cancer. Dietary modification therefore has the promise of reducing colorectal cancer incidence. PMID:25575572

  12. Porous membrane utilization in plant nutrient delivery

    Science.gov (United States)

    Dreschel, T. W.; Hinkle, C. R.; Prince, R. P.; Knott, W. M., III

    1987-01-01

    A spacecraft hydroponic plant growth unit of tubular configuration, employing a microporous membrane as a capilary interface between plant roots and a nutrient solution, is presented. All three of the experimental trials undertaken successfully grew wheat from seed to harvest. Attention is given to the mass/seed, number of seeds/head, ratio of seed dry mass to total plant dry mass, production of tillers, and mass of seed/plant. Dry matter production is found to be reduced with increasing suction pressure; this is true for both average seed and average total dry matter/plant. This may be due to a reduction in water and nutrient availability through the microporous membrane.

  13. The variability in nutrient composition of Anaerobic Digestate granules produced from high shear granulation.

    Science.gov (United States)

    Mangwandi, Chirangano; JiangTao, Liu; Albadarin, Ahmad B; Allen, Stephen J; Walker, Gavin M

    2013-01-01

    This study investigates the production of organic fertilizer using Anaerobic Digestate (as a nutrient source) and limestone powder as the raw materials. A two-level factorial experimental design was used to determine the influence of process variables on the nutrient homogeneity within the granules. Increasing the liquid-to-solid ratio during granulation resulted in increased granule nutrient homogeneity. Increasing the processing time and the impeller speed were also found to increase the nutrient homogeneity. In terms of nutrients release into deionized water, the granules effectively released both potassium and phosphate into solution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. The influence of the forest canopy on nutrient cycling.

    Science.gov (United States)

    Prescott, Cindy E

    2002-11-01

    Rates of key soil processes involved in recycling of nutrients in forests are governed by temperature and moisture conditions and by the chemical and physical nature of the litter. The forest canopy influences all of these factors and thus has a large influence on nutrient cycling. The increased availability of nutrients in soil in clearcuts illustrates how the canopy retains nutrients (especially N) on site, both by storing nutrients in foliage and through the steady input of available C in litter. The idea that faster decomposition is responsible for the flush of nitrate in clearcuts has not been supported by experimental evidence. Soil N availability increases in canopy gaps as small as 0.1 ha, so natural disturbances or partial harvesting practices that increase the complexity of the canopy by creating gaps will similarly increase the spatial variability in soil N cycling and availability within the forest. Canopy characteristics affect the amount and composition of leaf litter produced, which largely determines the amount of nutrients to be recycled and the resulting nutrient availability. Although effects of tree species on soil nutrient availability were thought to be brought about largely through differences in the decomposition rate of their foliar litter, recent studies indicate that the effect of tree species can be better predicted from the mass and nutrient content of litter produced, hence total nutrient return, than from litter decay rate. The greater canopy complexity in mixed species forests creates similar heterogeneity in nutritional characteristics of the forest floor. Site differences in slope position, parent material and soil texture lead to variation in species composition and productivity of forests, and thus in the nature and amount of litter produced. Through this positive feedback, the canopy accentuates inherent differences in site fertility.

  15. Nutrients and neurodevelopment: lipids.

    Science.gov (United States)

    González, Horacio F; Visentin, Silvana

    2016-10-01

    Nutrients, lipids in particular, make up the central nervous system structure and play major functional roles: they stimulate development, migration, and nerve cell differentiation. They are part of gray matter, white matter, nerve nuclei, and synaptogenesis. Breast milk contains lipids which are crucial for infant brain development. The lipid profile of breast milk was used as a guideline for the development of breast milk substitutes. However, to date, no substitute has matched it. Complementary feeding should include docosahexaenoic acid, arachidonic acid, other polyunsaturated fatty acids, saturated fatty acids, and complex lipids found in milk fat. The lipid composition of breast milk depends on maternal intake and nutritional status during pregnancy and breast-feeding. It has a great impact on development. Our goal is to review scientific literature regarding the role of lipids on infant brain development and the importance of breast milk lipid composition, maternal diet, and complementary feeding. Sociedad Argentina de Pediatría.

  16. Effect of Processing Methods on the Nutrients and Anti Nutrients ...

    African Journals Online (AJOL)

    The nutrients and antinutrients compositions of vegetables cannot be over emphasized. The effect of different processing methods on the nutrients and antinutrients compositions in leaves of wild lettuce (Lactuca taraxacifolia) i.e. the sweet type was evaluated to determine the most appropriate methods for retaining its ...

  17. Nutrients and Anti Nutrients Composition of Two Varieties of Sorrel ...

    African Journals Online (AJOL)

    Objective: To determine the nutrients and anti nutrients composition of sorrel leaves and seeds from red and yellow calyx plants. Materials and methods: Fresh leaves and dry seeds of the two varieties were cleaned and milled. Standard assay techniques were used to evaluate the two varieties of the leaves and seeds for ...

  18. Nutrient and Anti-nutrient Composition of Cereal Products ...

    African Journals Online (AJOL)

    Content of iron was higher in all the cereal products and levels of antinutrient analyzed were within safe levels. Conclusion: Nutrient density of commonly consumed cereal products in Samaru – Zaria is low but the levels of antinutrient in the cereal product were within the safe levels. Key words: Cereal products, Nutrient ...

  19. Biotechnology of nutrient uptake and assimilation in plants.

    Science.gov (United States)

    López-Arredondo, Damar L; Leyva-González, Marco A; Alatorre-Cobos, Fulgencio; Herrera-Estrella, Luis

    2013-01-01

    Plants require a complex balance of mineral nutrients to reproduce successfully. Because the availability of many of these nutrients in the soil is compromised by several factors, such as soil pH, cation presence, and microbial activity, crop plants depend directly on nutrients applied as fertilizers to achieve high yields. However, the excessive use of fertilizers is a major environmental concern due to nutrient leaching that causes water eutrophication and promotes toxic algae blooms. This situation generates the urgent need for crop plants with increased nutrient use efficiency and better-designed fertilization schemes. The plant biology revolution triggered by the development of efficient gene transfer systems for plant cells together with the more recent development of next-generation DNA and RNA sequencing and other omics platforms have advanced considerably our understanding on the molecular basis of plant nutrition and how plants respond to nutritional stress. To date, genes encoding sensors, transcription factors, transporters, and metabolic enzymes have been identified as potential candidates to improve nutrient use efficiency. In addition, the study of other genetic resources, such as bacteria and fungi, allows the identification of alternative mechanisms of nutrient assimilation, which are potentially applicable in plants. Although significant progress in this respect has been achieved by conventional breeding, in this review we focus on the biotechnological approaches reported to date aimed at boosting the use of the three most limiting nutrients in the majority of arable lands: nitrogen, phosphorus, and iron.

  20. Patterns of Ca/Sr and 87Sr/ 86Sr variation before and after a whole watershed CaSiO 3 addition at the Hubbard Brook Experimental Forest, USA

    Science.gov (United States)

    Nezat, Carmen A.; Blum, Joel D.; Driscoll, Charles T.

    2010-06-01

    Forty-one metric tons of the mineral wollastonite (CaSiO 3) was applied to an 11.8 hectare watershed at the Hubbard Brook Experimental Forest (HBEF; White Mountains, New Hampshire, USA) with the goal of restoring the Ca estimated to have been depleted from the soil exchange complex by acid deposition. This experiment provided an opportunity to gain qualitative information on whole watershed hydrologic flow paths by studying the response of stream water chemistry to the addition of Ca. Because the Ca/Sr and 87Sr/ 86Sr ratios of wollastonite strongly contrast that of other Ca sources in the watershed, the wollastonite-derived Ca can be identified and its amount estimated in various ecosystem components. Stream water chemistry at the HBEF varies seasonally due to shifts in the proportion of base flow and interflow. Prior to the wollastonite application, seasonal variations in 87Sr/ 86Sr ratios indicated that 87Sr/ 86Sr was higher during base flow than interflow, due largely to greater amounts of biotite weathering along deeper flow paths. After the application, Ca/Sr and 87Sr/ 86Sr changed markedly as the high Ca/Sr and low 87Sr/ 86Sr wollastonite dissolved and mixed with stream water. The Ca addition provided information on the response times of various flow paths and ion exchange processes to Ca addition in this small upland watershed. During the first year after the addition, wollastonite applied to the near stream zone dissolved and was partially immobilized by cation exchange sites in the hyporheic zone. In the second and third years after the addition we infer that much of this Ca and Sr was subsequently desorbed from the hyporheic zone and was exported from the watershed in stream flow. In the fourth through ninth years after the addition, Ca and Sr from wollastonite that had dissolved in upland soils was transported to the stream by interflow during wet periods when the ground water table was elevated. Between years three and nine the minimum annual Ca

  1. Integrated Nutrient Management on Soil Properties and Nutrient Uptake by Red Onion

    Directory of Open Access Journals (Sweden)

    Emmanuel Kwada Kwaghe

    2017-06-01

    Full Text Available Field experiments were carried out during the dry seasons in (2012-2013 and 2013-2014 to study the impact of Integrated Nutrient Management on some soil properties and nutrients uptake by red onion (Allium cepa L. in Moda, Michika, Adamawa state, Nigeria. Soil samples were randomly collected and analysed for pH, EC, organic carbon, organic matter, total nitrogen, available phosphorus before and at the completion of the experiment. Total nitrogen, phosphorus and potassium contents of the onion bulbs were determined. There was an improvement in the fertility status of the soil as a consequence of integrated nutrient management. Combined organic and inorganic fertilizer application influenced the uptake of nitrogen, phosphorus and potassium by red onion. The highest nitrogen, phosphorous and potassium uptake by onions of 0.76, 43.82 and 2.42kgha-1 occurred when all treatments were combined. Uptake of N and K increased as treatment level increased. The P uptake was highest at lower treatment levels and could be linked to sufficiency of indigenous soil P for plant growth resulting in high P uptake with minimal addition of nutrient inputs. Integrated Nutrient Management could be adopted to improve soil fertility status and N, P and K uptake by red onions.

  2. Nutrients' removal from aquaculture wastewater using the macroalgae Gracilaria birdiae

    Energy Technology Data Exchange (ETDEWEB)

    Marinho-Soriano, E.; Nunes, S.O.; Carneiro, M.A.A.; Pereira, D.C. [Universidade Federal do Rio Grande do Norte, Depto. de Oceanografia e Limnologia, Via Costeira, Praia de Mae Luiza, s/n, Natal, RN 59014-100 (Brazil)

    2009-02-15

    Intensive aquaculture releases large amount of nutrients into aquatic ecosystems and can lead to eutrophication of coastal waters. Studies conducted in aquaculture systems have demonstrated that the seaweeds are efficient in reducing nutrients and at the same time provides extra income, when species of economic importance are used. This study was conducted to evaluate whether Gracilaria birdiae could be cultivated efficiently for the production of useful algal biomass and removal of nutrients from shrimp pond effluents. The results obtained showed a gradual increase in biomass and relative growth rate (RGR) over the experimental period. Mean RGR between the weeks varied significantly (p < 0.01), reaching a maximum of 3.6 {+-} 0.35% d{sup -1} and a minimum of 1.6 {+-} 0.52% d{sup -1}. The mean for the whole period was 2.6% d{sup -1}. The biofiltration capacity of G. birdiae was confirmed by the significantly reduced concentration of the three nutrients analyzed (PO{sub 4}{sup 3-}, NH{sub 4}{sup +} and NO{sub 3}{sup -}) over the study period. The concentration of PO{sub 4}{sup 3-} decreased by 93.5%, NH{sub 4}{sup +} by 34% and NO{sub 3}{sup -} by 100% after the 4-week experimental period. The results obtained in this study indicated that G. birdiae can be used in aquaculture systems as a biofilter. In addition, the macroalgae biomass produced offers alternative source of raw material for the extraction of the phycocolloid agar, human food and animal feed. (author)

  3. Nutrient solutions for soilless cultures

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    Nutrient solutions intended for plant growth are already used from the middle of the 19th century, when the importance of mineral elements for plant growth was made clear by Justus von Liebig. In advance, the nutrient solutions used to grow plants in so called “water cultures” had a simple

  4. The Nutrient Density of Snacks

    Directory of Open Access Journals (Sweden)

    Julie Hess BA

    2017-03-01

    Full Text Available Background: Although Americans receive almost a quarter of their daily energy from snacks, snacking remains a poorly defined and understood eating occasion. However, there is little dietary guidance about choosing snacks. Families, clinicians, and researchers need a comprehensive approach to assessing their nutritional value. Objective: To quantify and compare the nutrient density of commonly consumed snacks by their overall nutrient profiles using the Nutrient-Rich Foods (NRF Index 10.3. Methods: NRF Index scores were calculated for the top 3 selling products (based on 2014 market research data in different snack categories. These NRF scores were averaged to provide an overall nutrient-density score for each category. Results: Based on NRF scores, yogurt (55.3, milk (52.5, and fruit (30.1 emerged as the most nutrient-dense snacks. Ice cream (−4.4, pies and cakes (−11.1, and carbonated soft drinks (−17.2 emerged as the most nutrient-poor snacks. Conclusions: The NRF Index is a useful tool for assessing the overall nutritional value of snacks based on nutrients to limit and nutrients to encourage.

  5. Nutrient management in substrate systems

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    Speaking about nutrient solutions in soilless cultivation, different solutions can be discerned. Originally, in soilless culture only one nutrient solution was taken into account, being the solution in the containers in which the plants were grown. Such solutions were intensively moved by air

  6. Effects of dietary additives (potassium diformate/organic acids) as well as influences of grinding intensity (coarse/fine) of diets for weaned piglets experimentally infected with Salmonella Derby or Escherichia coli.

    Science.gov (United States)

    Taube, V A; Neu, M E; Hassan, Y; Verspohl, J; Beyerbach, M; Kamphues, J

    2009-06-01

    The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed-withholding-period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6-mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4-5 h after a further oral application of approximately 10(9)-10(10) CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.

  7. Interactions between temperature and nutrients across levels of ecological organization.

    Science.gov (United States)

    Cross, Wyatt F; Hood, James M; Benstead, Jonathan P; Huryn, Alexander D; Nelson, Daniel

    2015-03-01

    Temperature and nutrient availability play key roles in controlling the pathways and rates at which energy and materials move through ecosystems. These factors have also changed dramatically on Earth over the past century as human activities have intensified. Although significant effort has been devoted to understanding the role of temperature and nutrients in isolation, less is known about how these two factors interact to influence ecological processes. Recent advances in ecological stoichiometry and metabolic ecology provide a useful framework for making progress in this area, but conceptual synthesis and review are needed to help catalyze additional research. Here, we examine known and potential interactions between temperature and nutrients from a variety of physiological, community, and ecosystem perspectives. We first review patterns at the level of the individual, focusing on four traits--growth, respiration, body size, and elemental content--that should theoretically govern how temperature and nutrients interact to influence higher levels of biological organization. We next explore the interactive effects of temperature and nutrients on populations, communities, and food webs by synthesizing information related to community size spectra, biomass distributions, and elemental composition. We use metabolic theory to make predictions about how population-level secondary production should respond to interactions between temperature and resource supply, setting up qualitative predictions about the flows of energy and materials through metazoan food webs. Last, we examine how temperature-nutrient interactions influence processes at the whole-ecosystem level, focusing on apparent vs. intrinsic activation energies of ecosystem processes, how to represent temperature-nutrient interactions in ecosystem models, and patterns with respect to nutrient uptake and organic matter decomposition. We conclude that a better understanding of interactions between temperature and

  8. The nutrient density approach to healthy eating: challenges and opportunities.

    Science.gov (United States)

    Nicklas, Theresa A; Drewnowski, Adam; O'Neil, Carol E

    2014-12-01

    The term 'nutrient density' for foods/beverages has been used loosely to promote the Dietary Guidelines for Americans. The 2010 Dietary Guidelines for Americans defined 'all vegetables, fruits, whole grains, fat-free or low-fat milk and milk products, seafood, lean meats and poultry, eggs, beans and peas (legumes), and nuts and seeds that are prepared without added solid fats, added sugars, and sodium' as nutrient dense. The 2010 Dietary Guidelines for Americans further states that nutrient-dense foods and beverages provide vitamins, minerals and other substances that may have positive health effects with relatively few (kilo)calories or kilojoules. Finally, the definition states nutrients and other beneficial substances have not been 'diluted' by the addition of energy from added solid fats, added sugars or by the solid fats naturally present in the food. However, the Dietary Guidelines Advisory Committee and other scientists have failed to clearly define 'nutrient density' or to provide criteria or indices that specify cut-offs for foods that are nutrient dense. Today, 'nutrient density' is a ubiquitous term used in the scientific literature, policy documents, marketing strategies and consumer messaging. However, the term remains ambiguous without a definitive or universal definition. Classifying or ranking foods according to their nutritional content is known as nutrient profiling. The goal of the present commentary is to address the research gaps that still exist before there can be a consensus on how best to define nutrient density, highlight the situation in the USA and relate this to wider, international efforts in nutrient profiling.

  9. THE EFFECT OF PHYTOADDITIVES ON BIOCHEMICAL INDICATORS AND NUTRIENTS DIGESTIBILITY IN SPORT HORSES NUTRITION

    Directory of Open Access Journals (Sweden)

    Branislav Galik

    2013-09-01

    Full Text Available The aim of the study was to determine the effect of a phylogenetic additive on blood serum indicator levels and faecal nutrients digestibility. The experiment was realized in Riding Centre of the Department of Animal Husbandry, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture in Nitra. Total 14 warmblood sport horses geldings were used 7 horses in control group, 7 horses in experimental group respectively, Slovak warmblood bred, average body weight 525 plus minus 75 kg and 6 8 plus minus 3 Years. The control group of horses were fed by crimped barley, meadow hay and mineral feed mixture. Feed rations in experimental group were supplemented with a photogenic additive containing a blend of essential oils from origanum, anise and citrus, as well as a prebiotic rich in fructooligosaccharides. Blood serum was collected 3 times during the experiment, in the beginning of the experiment, and every 45 days. The experiment lasted 90 days. After the 45 days of phytoadditive supplementation we found a tendency of lower concentrations of serum triglycerides milimol l and total cholesterol milimol 1 in experimental group of horses P. In serum concentrations of glucose, total proteins and urea we find similar values in all of groups. We analyzed a positive effect of phylogenetic additive on organic matter digestibility of feed ration. In experimental group of horses we found significantly, higher organic matter faecal digestibility coefficient 73 per cent in comparison with control group 68 per cent. We analyzed insignificant effect of a phytoadditive on blood serum concentrations during 90 days of experiment. We found positive effect of phytoadditve supplementation on total faecal digestibility of organic nutrients.

  10. Approaches and uncertainties in nutrient budgets; Implications for nutrient management and environmental policies

    NARCIS (Netherlands)

    Oenema, O.; Kros, J.; Vries, de W.

    2003-01-01

    Nutrient budgets of agroecosystems are constructed either (i) to increase the understanding of nutrient cycling, (ii) as performance indicator and awareness raiser in nutrient management and environmental policy, or (iii) as regulating policy instrument to enforce a certain nutrient management

  11. Nutrient limitation in Northern Gulf of Mexico (NGOM): phytoplankton communities and photosynthesis respond to nutrient pulse.

    Science.gov (United States)

    Zhao, Yan; Quigg, Antonietta

    2014-01-01

    Although the Mississippi-Atchafalaya River system exports large amounts of nutrients to the Northern Gulf of Mexico annually, nutrient limitation of primary productivity still occurs offshore, acting as one of the major factors controlling local phytoplankton biomass and community structure. Bioassays were conducted for 48 hrs at two stations adjacent to the river plumes in April and August 2012. High Performance of Liquid Chromatography (HPLC) combined with ChemTax and a Fluorescence Induction and Relaxation (FIRe) system were combined to observe changes in the phytoplankton community structure and photosynthetic activity. Major fluorescence parameters (Fo, Fv/Fm) performed well to reveal the stimulating effect of the treatments with nitrogen (N-nitrate) and with nitrogen plus phosphate (+NPi). HPLC/ChemTax results showed that phytoplankton community structure shifted with nitrate addition: we observed an increase in the proportion of diatoms and prasinophytes and a decrease in cyanobacteria and prymnesiophytes. These findings are consistent with predictions from trait-based analysis which predict that phytoplankton groups with high maximum growth rates (μmax ) and high nutrient uptake rates (Vmax ) readily take advantage of the addition of limiting nutrients. Changes in phytoplankton community structure, if persistent, could trigger changes of particular organic matter fluxes and alter the micro-food web cycles and bottom oxygen consumption.

  12. Nutrient limitation in Northern Gulf of Mexico (NGOM: phytoplankton communities and photosynthesis respond to nutrient pulse.

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    Full Text Available Although the Mississippi-Atchafalaya River system exports large amounts of nutrients to the Northern Gulf of Mexico annually, nutrient limitation of primary productivity still occurs offshore, acting as one of the major factors controlling local phytoplankton biomass and community structure. Bioassays were conducted for 48 hrs at two stations adjacent to the river plumes in April and August 2012. High Performance of Liquid Chromatography (HPLC combined with ChemTax and a Fluorescence Induction and Relaxation (FIRe system were combined to observe changes in the phytoplankton community structure and photosynthetic activity. Major fluorescence parameters (Fo, Fv/Fm performed well to reveal the stimulating effect of the treatments with nitrogen (N-nitrate and with nitrogen plus phosphate (+NPi. HPLC/ChemTax results showed that phytoplankton community structure shifted with nitrate addition: we observed an increase in the proportion of diatoms and prasinophytes and a decrease in cyanobacteria and prymnesiophytes. These findings are consistent with predictions from trait-based analysis which predict that phytoplankton groups with high maximum growth rates (μmax and high nutrient uptake rates (Vmax readily take advantage of the addition of limiting nutrients. Changes in phytoplankton community structure, if persistent, could trigger changes of particular organic matter fluxes and alter the micro-food web cycles and bottom oxygen consumption.

  13. Nutrient removal from farm effluents.

    Science.gov (United States)

    Bolan, N S; Wong, L; Adriano, D C

    2004-09-01

    The objectives of the study were: (i) to examine the efficiency of nutrient removal during the treatment of dairy farm effluent in a two-pond system, and (ii) to produce an inexpensive but effective nutrient trap which could be recycled as a nutrient source or soil mulch. The concentration of chemical oxygen demand (COD), biological oxygen demand (BOD), nitrogen (N), phosphorus (P) and potassium (K) in a two-pond system used to treat dairy farm effluent was monitored over a period of 7 months. The retention of nutrients by two porous materials was examined both in the laboratory batch (zeolite and bark) and pilot-scale field (bark) experiments. The results indicated that biological treatment of farm effluents using the two-pond system was not effective in the removal of nutrients, which are likely to become pollutant when discharged to waterways. Both the bark and zeolite materials were effective in the removal of N, P and K from effluent. These materials can be placed in the second (i.e., aerobic) pond to treat effluents, which can then be discharged to streams with minimum impact on water quality. The nutrient-enriched porous materials can be recycled as a source of nutrients and soil conditioner.

  14. Functional traits determine tree growth and ecosystem productivity of a tropical montane forest: Insights from a long-term nutrient manipulation experiment.

    Science.gov (United States)

    Báez, Selene; Homeier, Jürgen

    2018-01-01

    Trait-response effects are critical to forecast community structure and biomass production in highly diverse tropical forests. Ecological theory and few observation studies indicate that trees with acquisitive functional traits would respond more strongly to higher resource availability than those with conservative traits. We assessed how long-term tree growth in experimental nutrient addition plots (N, P, and N + P) varied as a function of morphological traits, tree size, and species identity. We also evaluated how trait-based responses affected stand scale biomass production considering the community structure. We found that tree growth depended on interactions between functional traits and the type or combination of nutrients added. Common species with acquisitive functional traits responded more strongly to nutrient addition, mainly to N + P. Phosphorous enhanced the growth rates of species with acquisitive and conservative traits, had mostly positive effects on common species and neutral or negative effects in rare species. Moreover, trees receiving N + P grew faster irrespective of their initial size relative to trees in control or to trees in other treatment plots. Finally, species responses were highly idiosyncratic suggesting that community processes including competition and niche dimensionality may be altered under increased resource availability. We found no statistically significant effects of nutrient additions on aboveground biomass productivity because acquisitive species had a limited potential to increase their biomass, possibly due to their generally lower wood density. In contrast, P addition increased the growth rates of species characterized by more conservative resource strategies (with higher wood density) that were poorly represented in the plant community. We provide the first long-term experimental evidence that trait-based responses, community structure, and community processes modulate the effects of increased nutrient

  15. Sequential nutrient uptake as a potential mechanism for phytoplankton to maintain high primary productivity and balanced nutrient stoichiometry

    Science.gov (United States)

    Yin, Kedong; Liu, Hao; Harrison, Paul J.

    2017-05-01

    We hypothesize that phytoplankton have the sequential nutrient uptake strategy to maintain nutrient stoichiometry and high primary productivity in the water column. According to this hypothesis, phytoplankton take up the most limiting nutrient first until depletion, continue to draw down non-limiting nutrients and then take up the most limiting nutrient rapidly when it is available. These processes would result in the variation of ambient nutrient ratios in the water column around the Redfield ratio. We used high-resolution continuous vertical profiles of nutrients, nutrient ratios and on-board ship incubation experiments to test this hypothesis in the Strait of Georgia. At the surface in summer, ambient NO3- was depleted with excess PO43- and SiO4- remaining, and as a result, both N : P and N : Si ratios were low. The two ratios increased to about 10 : 1 and 0. 45 : 1, respectively, at 20 m. Time series of vertical profiles showed that the leftover PO43- continued to be removed, resulting in additional phosphorus storage by phytoplankton. The N : P ratios at the nutricline in vertical profiles responded differently to mixing events. Field incubation of seawater samples also demonstrated the sequential uptake of NO3- (the most limiting nutrient) and then PO43- and SiO4- (the non-limiting nutrients). This sequential uptake strategy allows phytoplankton to acquire additional cellular phosphorus and silicon when they are available and wait for nitrogen to become available through frequent mixing of NO3- (or pulsed regenerated NH4). Thus, phytoplankton are able to maintain high productivity and balance nutrient stoichiometry by taking advantage of vigorous mixing regimes with the capacity of the stoichiometric plasticity. To our knowledge, this is the first study to show the in situ dynamics of continuous vertical profiles of N : P and N : Si ratios, which can provide insight into the in situ dynamics of nutrient stoichiometry in the water column and the inference of

  16. Nutrient Administration and Resistance Training

    Directory of Open Access Journals (Sweden)

    Leutholtz Brian

    2005-06-01

    Full Text Available Abstract Skeletal muscle tissue is tightly regulated throughout our bodies by balancing its synthesis and breakdown. Many factors are known to exist that cause profound changes on the overall status of skeletal muscle, some of which include exercise, nutrition, hormonal influences and disease. Muscle hypertrophy results when protein synthesis is greater than protein breakdown. Resistance training is a popular form of exercise that has been shown to increase muscular strength and muscular hypertrophy. In general, resistance training causes a stimulation of protein synthesis as well as an increase in protein breakdown, resulting in a negative balance of protein. Providing nutrients, specifically amino acids, helps to stimulate protein synthesis and improve the overall net balance of protein. Strategies to increase the concentration and availability of amino acids after resistance exercise are of great interest and have been shown to effectively increase overall protein synthesis. 123 After exercise, providing carbohydrate has been shown to mildly stimulate protein synthesis while addition of free amino acids prior to and after exercise, specifically essential amino acids, causes a rapid pronounced increase in protein synthesis as well as protein balance.13 Evidence exists for a dose-response relationship of infused amino acids while no specific regimen exists for optimal dosing upon ingestion. Ingestion of whole or intact protein sources (e.g., protein powders, meal-replacements has been shown to cause similar improvements in protein balance after resistance exercise when compared to free amino acid supplements. Future research should seek to determine optimal dosing of ingested intact amino acids in addition to identifying the cellular mechanistic machinery (e.g. transcriptional and translational mechanisms for causing the increase in protein synthesis.

  17. Decomposition, nutrient release patterns and nutrient fluxes from ...

    African Journals Online (AJOL)

    Studies were conducted on leaf litter fall, decomposition, nutrient release patterns and nutrient fluxes of Akyaakrom (AS) and Dopiri (DS) secondary forest leaf litter in Dwinyama watershed. Leaf litter production were 9.1 and 6.8 t ha-1 y-1 in AS and 8.9 and 6.5 t ha-1 y-1 in DS in the 1st (September 1998-August 1999) and ...

  18. Nutrient Content and Nutritional Water Productivity of Selected Grain Legumes in Response to Production Environment.

    Science.gov (United States)

    Chibarabada, Tendai Polite; Modi, Albert Thembinkosi; Mabhaudhi, Tafadzwanashe

    2017-10-26

    There is a need to incorporate nutrition into aspects of crop and water productivity to tackle food and nutrition insecurity (FNS). The study determined the nutritional water productivity (NWP) of selected major (groundnut, dry bean) and indigenous (bambara groundnut and cowpea) grain legumes in response to water regimes and environments. Field trials were conducted during 2015/16 and 2016/17 at three sites in KwaZulu-Natal, South Africa (Ukulinga, Fountainhill and Umbumbulu). Yield and evapotranspiration (ET) data were collected. Grain was analysed for protein, fat, Ca, Fe and Zn nutrient content (NC). Yield, ET and NC were then used to compute NWP. Overall, the major legumes performed better than the indigenous grain legumes. Groundnut had the highest NWPfat. Groundnut and dry bean had the highest NWPprotein. For NWPFe, Zn and Ca, dry bean and cowpea were more productive. Yield instability caused fluctuations in NWP. Water treatments were not significant (p > 0.05). While there is scope to improve NWP under rainfed conditions, a lack of crop improvement currently limits the potential of indigenous grain legumes. This provides an initial insight on the nutrient content and NWP of a limited number of selected grain legumes in response to the production environment. There is a need for follow-up research to include cowpea data. Future studies should provide more experimental data and explore effects of additional factors such as management practices (fertiliser levels and plant density), climate and edaphic factors on nutrient content and NWP of crops.

  19. Nutrient Content and Nutritional Water Productivity of Selected Grain Legumes in Response to Production Environment

    Directory of Open Access Journals (Sweden)

    Tendai Polite Chibarabada

    2017-10-01

    Full Text Available There is a need to incorporate nutrition into aspects of crop and water productivity to tackle food and nutrition insecurity (FNS. The study determined the nutritional water productivity (NWP of selected major (groundnut, dry bean and indigenous (bambara groundnut and cowpea grain legumes in response to water regimes and environments. Field trials were conducted during 2015/16 and 2016/17 at three sites in KwaZulu-Natal, South Africa (Ukulinga, Fountainhill and Umbumbulu. Yield and evapotranspiration (ET data were collected. Grain was analysed for protein, fat, Ca, Fe and Zn nutrient content (NC. Yield, ET and NC were then used to compute NWP. Overall, the major legumes performed better than the indigenous grain legumes. Groundnut had the highest NWPfat. Groundnut and dry bean had the highest NWPprotein. For NWPFe, Zn and Ca, dry bean and cowpea were more productive. Yield instability caused fluctuations in NWP. Water treatments were not significant (p > 0.05. While there is scope to improve NWP under rainfed conditions, a lack of crop improvement currently limits the potential of indigenous grain legumes. This provides an initial insight on the nutrient content and NWP of a limited number of selected grain legumes in response to the production environment. There is a need for follow-up research to include cowpea data. Future studies should provide more experimental data and explore effects of additional factors such as management practices (fertiliser levels and plant density, climate and edaphic factors on nutrient content and NWP of crops.

  20. Frequency of recirculation of nutrient solution in hydroponic cultivation of coriander with brackish water

    Directory of Open Access Journals (Sweden)

    Mairton G. da Silva

    2016-05-01

    Full Text Available ABSTRACT The present study used a hydroponic system with leveled channels, in order to evaluate coriander cultivation under different intervals of nutrient solution recirculation and the use of freshwater and brackish water. The experiment was carried out in a randomized block design with five replicates, in a 2 x 4 factorial scheme, from February to March 2014. Two levels of electrical conductivity (EC of water (0.32 and 4.91 dS m-1 and four frequencies of nutrient solution recirculation (at intervals of 0.25, 2, 4 and 8 h were evaluated. This experimental design was adopted in the evaluations performed at 10, 15 and 25 days after transplantation (DAT. Additionally, at 21 DAT subplots were established for the evaluation of plant position (initial, intermediate and final along the hydroponic channels. It is viable to use nutrient solution recirculation every 8 h, without production losses. The use of brackish water (EC = 4.91 dS m-1 may be an alternative for the hydroponic cultivation of coriander, despite the reduction in production, but without any damage on the visual aspect of the product. Plants grown at the initial and intermediate positions along the hydroponic channels showed higher production.

  1. Dopamine alleviates nutrient deficiency-induced stress in Malus hupehensis.

    Science.gov (United States)

    Liang, Bowen; Li, Cuiying; Ma, Changqing; Wei, Zhiwei; Wang, Qian; Huang, Dong; Chen, Qi; Li, Chao; Ma, Fengwang

    2017-10-01

    Dopamine mediates many physiological processes in plants. We investigated its role in regulating growth, root system architecture, nutrient uptake, and responses to nutrient deficiencies in Malus hupehensis Rehd. Under a nutrient deficiency, plants showed significant reductions in growth, chlorophyll concentrations, and net photosynthesis, along with disruptions in nutrient uptake, transport, and distribution. However, pretreatment with 100 μM dopamine markedly alleviated such inhibitions. Supplementation with that compound enabled plants to maintain their photosynthetic capacity and development of the root system while promoting the uptake of N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and B, altering the way in which those nutrients were partitioned throughout the plant. The addition of dopamine up-regulated genes for antioxidant enzymes involved in the ascorbate-glutathione cycle (MdcAPX, MdcGR, MdMDHAR, MdDHAR-1, and MdDHAR-2) but down-regulated genes for senescence (SAG12, PAO, and MdHXK). These results indicate that exogenous dopamine has an important antioxidant and anti-senescence effect that might be helpful for improving nutrient uptake. Our findings demonstrate that dopamine offers new opportunities for its use in agriculture, especially when addressing the problem of nutrient deficiencies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Growth performance and nutrient digestibility of broiler chickens fed ...

    African Journals Online (AJOL)

    Two hundred and seventy (270), day old chicks were used in a completely randomized design experimental layout to test the growth performance and nutrient digestibility of broiler chickens fed single phase diets containing natuzyme™ treated groundnut shell at 0, 5, 10, 15, 20 and 25 % inclusion levels. The treatments ...

  3. Nutrient and Coliform Loading (NCL)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a database of available fecal coliform bacteria, fecal streptococci bacteria, and nutrient loading data. Loading for contaminants other than fecal coliform...

  4. Identification and quantification of nitrogen nutrient deficiency in the activated sludge process using respirometry

    NARCIS (Netherlands)

    Ning, Z.; Patry, G.G.; Spanjers, H.

    2000-01-01

    Experimental protocols to identify and quantify nitrogen nutrient deficiency in the activated sludge process were developed and tested using respirometry. Respirometric experiments showed that when a nitrogen nutrient deficient sludge is exposed to ammonia nitrogen, the oxygen uptake rate (OUR) of

  5. Phase stability of AlMgB{sub 14} based materials and Ge{sub 2}Sb{sub 2}Te{sub 5} with Si and N additions studied by theoretical and experimental means

    Energy Technology Data Exchange (ETDEWEB)

    Koelpin, Helmut

    2011-07-01

    in Ge{sub 2}Sb{sub 2}Te{sub 5} (space group Fm anti 3m) on structure and phase stability thereof was studied experimentally by thin film growth and characterization as well as theoretically by ab initio calculations. It was found that Si and N most probably accumulate in the amorphous matrix embedding Ge{sub 2}Sb{sub 2}Te{sub 5} grains. The incorporation of Si and N in these samples causes an increase of the crystallization temperature and the formation of finer grains. N is more efficient in increasing the crystallization temperature and in reducing the grain size than Si, which can be understood based on the bonding analysis. The incorporation of both Si and N in Ge{sub 2}Sb{sub 2}Te{sub 5} is energetically unfavorable, leading to finer grains and larger crystallization temperatures. While in the case of Si additions no significant changes in bonding are observe, N additions appear to enable the formation of strong Te-N bonds in the amorphous matrix, which are shown to be almost twice as strong as the strongest bonds in unalloyed Ge{sub 2}Sb{sub 2}Te{sub 5}. (orig.)

  6. Nutrient and media recycling in heterotrophic microalgae cultures.

    Science.gov (United States)

    Lowrey, Joshua; Armenta, Roberto E; Brooks, Marianne S

    2016-02-01

    In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work.

  7. Losses through gases and effluent and nutritional value of Brachiaria decumbens with addition of soybean hulls

    Directory of Open Access Journals (Sweden)

    Carlos Clayton Oliveira Dantas

    2014-05-01

    Full Text Available The objective of this experiment was to evaluate the losses of nutrient through gases and effluents, the nutrient recovery, fermentation parameters and the chemical parameters of silages of Brachiaria decumbens with the addition of soybean hulls, testing five levels of inclusion: 0, 10, 20, 30 and 40% (as is, with five replications per treatment. After the standardization cut of the forage, performed at 5 cm from the soil level, the soil was fertilized with nitrogen and potassium in the form of ammonium sulfate and potassium chloride, respectively, at 60 kg/ha. After 60 days, the grass was cut at 10 cm from the soil and ensiled. Experimental silos with capacity of 10 liters with Bunsen valve were used. Silos had 3 kg of sand conditioned at the bottom for retention of the effluents. The results show that the contents of dry matter, crude protein, acid detergent insoluble fiber and total digestible nutrients presented positive linear behavior with the inclusion of soybean hulls. In the grass silages with addition of soybean hulls, there was greater recovery of dry matter in relation to the control silage, which is a reflection of the negative linear behavior for the values of losses of gases and effluent. There was quadratic behavior in the pH values and negative linear behavior for the ammonia N values and buffering capacity with the inclusion of the additive in the grass silage. Inclusion of soybean hulls is sufficient to improve the fermentation pattern and minimize the losses through gases and effluents, contributing to the nutrient recovery, in addition to promoting overall improvement of the nutritional value of Brachiaria grass silages.

  8. Effect of nutrients and salinity pulses on biomass and growth of Vallisneria americana in lower St Johns River, FL, USA.

    Science.gov (United States)

    Boustany, Ronald G; Michot, Thomas C; Moss, Rebecca F

    2015-02-01

    We determined the interactive effects of nutrient loading and salinity pulsing on Vallisneria americana Michx., the dominant submerged aquatic vegetation species in the lower St Johns River (LSJR), FL, USA, and its associated algal community. Five hundred and ninety 6-inch diameter intact plant plugs of Vallisneria were collected from the LSJR in March 2003 and transported to US Geological Survey mesocosm facilities in Lafayette, LA, USA. A 3×3 experimental design consisting of three nutrient levels (control, 1/3 control and 3× control) and three salinity pulsing regimes (no pulse, 1-pulse at 18 ppt and 2-pulse at 12 and 18 ppt) was implemented with three replicates per treatment for a total of 27 experimental tanks. Salinity pulsing significantly reduced all measured Vallisneria growth parameters including above- and below-ground biomass, areal productivity and leaf area index. Nutrient levels had little effect on plants subjected to salinity pulses, but in non-salinity pulse treatments we observed higher mean macrophyte biomass in the low-nutrient loading treatments. Macroalgal components (epiphytes and surface algal mats) were not significantly different ( p=0.2998 and p=0.2444, respectively), but water column chlorophyll a (phytoplankton) was significantly higher ( psalinity pulse treatments except for the 1-pulse, low-nutrient treatment. A single salinity pulse at 18 ppt resulted in 22% pot mortality and two consecutive pulses of 18 and 12 ppt resulted in an additional 14% mortality. Individual leaves and ramets lost 59.7% and 67.8%, respectively, in the combined salinity pulse treatments. Nutrient loading tends to have a long-term effect on Vallisneria through complex community interactions while salinity pulsing frequency and intensity has an immediate and direct influence on growth and distribution.

  9. Effects of dietary brown propolis on nutrient intake and digestibility in feedlot lambs

    Directory of Open Access Journals (Sweden)

    Jonilson Araújo da Silva

    2014-07-01

    Full Text Available The present study tested brown propolis in crude or extract form as a feed supplement for feedlot lambs to identify the type that most improves in vivo nutrient digestibility. Digestibility was assessed by both total fecal collection and internal markers and the results obtained by these techniques were compared. The completely randomized design was used to compare feed intake and nutrient digestibility of 24 male lambs aged seven months among four dietary treatments (crude brown propolis, propolis ethanol extract, monensin sodium, and control. Methods of feces collection were compared using a completely randomized split-plot design, with experimental diets corresponding to the main factor and the methods to estimate fecal production as the sub-factor. The diets had a roughage:concentrate ratio of 50:50, with Tifton-85 bermudagrass hay (Cynodon spp. as roughage, and ground corn, soybean meal and minerals as concentrate. The lambs fed diets with crude propolis had higher feed intake than those fed diets containing monensin sodium. The different diets did not affect dry matter, organic matter, crude protein, neutral detergent fiber, or acid detergent fiber digestibility, but crude propolis supplementation provided higher ether extract digestibility than monensin sodium. Nutrient digestibility, as indicated by indigestible neutral detergent fiber, indigestible acid detergent fiber and sequentially-determined indigestible acid detergent fiber, was lower than that found with the fecal collection method. The addition of brown propolis has the same effect as monensin, but neither maximized nutrient availability in the diet of feedlot lambs at 7 months of age. Digestibility assessment using the internal markers indigestible neutral detergent fiber, indigestible acid detergent fiber and sequentially-determined indigestible acid detergent fiber is not an efficient method compared with total feces collection.

  10. Nutrient acquisition strategies of mammalian cells.

    Science.gov (United States)

    Palm, Wilhelm; Thompson, Craig B

    2017-06-07

    Mammalian cells are surrounded by diverse nutrients, such as glucose, amino acids, various macromolecules and micronutrients, which they can import through transmembrane transporters and endolysosomal pathways. By using different nutrient sources, cells gain metabolic flexibility to survive periods of starvation. Quiescent cells take up sufficient nutrients to sustain homeostasis. However, proliferating cells depend on growth-factor-induced increases in nutrient uptake to support biomass formation. Here, we review cellular nutrient acquisition strategies and their regulation by growth factors and cell-intrinsic nutrient sensors. We also discuss how oncogenes and tumour suppressors promote nutrient uptake and thereby support the survival and growth of cancer cells.

  11. An introduced predator alters Aleutian Island plant communities by thwarting nutrient subsidies

    Science.gov (United States)

    Maron, J.L.; Estes, J.A.; Croll, D.A.; Danner, E.M.; Elmendorf, S.C.; Buckelew, S.L.

    2006-01-01

    The ramifying effects of top predators on food webs traditionally have been studied within the framework of trophic cascades. Trophic cascades are compelling because they embody powerful indirect effects of predators on primary production. Although less studied, indirect effects of predators may occur via routes that are not exclusively trophic. We quantified how the introduction of foxes onto the Aleutian Islands transformed plant communities by reducing abundant seabird populations, thereby disrupting nutrient subsidies vectored by seabirds from sea to land. We compared soil and plant fertility, plant biomass and community composition, and stable isotopes of nitrogen in soil, plants, and other organisms on nine fox-infested and nine historically fox-free islands across the Aleutians. Additionally, we experimentally augmented nutrients on a fox-infested island to test whether differences in plant productivity and composition between fox-infested and fox-free islands could have arisen from differences in nutrient inputs between island types. Islands with historical fox infestations had soils low in phosphorus and nitrogen and plants low in tissue nitrogen. Soils, plants, slugs, flies, spiders, and bird droppings on these islands had low d15N values indicating that these organisms obtained nitrogen from internally derived sources. In contrast, soils, plants, and higher trophic level organisms on fox-free islands had elevated d15N signatures indicating that they utilized nutrients derived from the marine environment. Furthermore, soil phosphorus (but not nitrogen) and plant tissue nitrogen were higher on fox-free than fox-infested islands. Nutrient subsidized fox-free islands supported lush, high biomass plant communities dominated by graminoids. Fox-infested islands were less graminoid dominated and had higher cover and biomass of low-lying forbs and dwarf shrubs. While d15N profiles of soils and plants and graminoid biomass varied with island size and distance from

  12. Soil nutrient availability and reproductive effort drive patterns in nutrient resorption in Pentachlethra macroloba

    Science.gov (United States)

    K. L. Tully; Tana Wood; A. M. Schwantes; D. Lawrence

    2013-01-01

    The removal of nutrients from senescing tissues, nutrient resorption, is a key strategy for conserving nutrients in plants. However, our understanding of what drives patterns of nutrient resorption in tropical trees is limited. We examined the effects of nutrient sources (stand-level and tree-level soil fertility) and sinks (reproductive effort) on nitrogen (N) and...

  13. CADDIS Volume 2. Sources, Stressors and Responses: Nutrients

    Science.gov (United States)

    Introduction to the nutrients module, when to list nutrients as a candidate cause, ways to measure nutrients, simple and detailed conceptual diagrams for nutrients, nutrients module references and literature reviews.

  14. Nutrient density: principles and evaluation tools.

    Science.gov (United States)

    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.

  15. Swift recovery of Sphagnum nutrient concentrations after excess supply.

    Science.gov (United States)

    Limpens, Juul; Heijmans, Monique M P D

    2008-08-01

    Although numerous studies have addressed the effects of increased N deposition on nutrient-poor environments such as raised bogs, few studies have dealt with to what extent, and on what time-scale, reductions in atmospheric N supply would lead to recovery of the ecosystems in question. Since a considerable part of the negative effects of elevated N deposition on raised bogs can be related to an imbalance in tissue nutrient concentrations of the dominant peat-former Sphagnum, changes in Sphagnum nutrient concentration after excess N supply may be used as an early indicator of ecosystem response. This study focuses on the N and P concentrations of Sphagnum magellanicum and Sphagnum fallax before, during and after a factorial fertilization experiment with N and P in two small peatlands subject to a background bulk deposition of 2 g N m(-2) year(-1). Three years of adding N (4.0 g N m(-2) year(-1)) increased the N concentration, and adding P (0.3 g P m(-2) year(-1)) increased the P concentration in Sphagnum relative to the control treatment at both sites. Fifteen months after the nutrient additions had ceased, N concentrations were similar to the control whereas P concentrations, although strongly reduced, were still slightly elevated. The changes in the N and P concentrations were accompanied by changes in the distribution of nutrients over the capitulum and the stem and were congruent with changes in translocation. Adding N reduced the stem P concentration, whereas adding P reduced the stem N concentration in favor of the capitulum. Sphagnum nutrient concentrations quickly respond to reductions in excess nutrient supply, indicating that a management policy aimed at reducing atmospheric nutrient input to bogs can yield results within a few years.

  16. Nutrient-enhancement of Matooke banana for improved nutrient ...

    African Journals Online (AJOL)

    A total of 173 PLHIVregistered with Rakai Health Science Project were chosen and interviewed using structured questionnaires to determine the current contribution of banana to the household food security. Nutrient intake data were collected using Gibson s 24-hour recall method and food frequency questionnaires.

  17. Anti-nutrients and mineral nutrient potential of gmelina ( Gmelina ...

    African Journals Online (AJOL)

    The study investigated the mineral and anti-nutrient composition of ripe gmelina whole fruit (RGWF), unripe gmelina whole fruit (UGWF) and ripe gmelina fruit pulp (RGFP) as potential livestock feed ingredients. The fruit pulp was low in alkanoid (0.14-0.58%DM), and phyto-haemaglutinnin (136- 276Hu/g) but high in tannin ...

  18. Shedding light onto nutrient responses of arbuscular mycorrhizal plants: nutrient interactions may lead to unpredicted outcomes of the symbiosis.

    Science.gov (United States)

    Corrêa, Ana; Cruz, Cristina; Pérez-Tienda, Jacob; Ferrol, Nuria

    2014-05-01

    The role and importance of arbuscular mycorrhizae (AM) in plant nitrogen (N) nutrition is uncertain. We propose that this be clarified by using more integrative experimental designs, with the use of a gradient of N supply and the quantification of an extensive array of plant nutrient contents. Using such an experimental design, we investigated AM effects on plant N nutrition, whether the mycorrhizal N response (MNR) determines the mycorrhizal growth response (MGR), and how MNR influences plants' C economy. Oryza sativa plants were inoculated with Rhizophagus irregularis or Funneliformis mossae. AM effects were studied along a gradient of N supplies. Biomass, photosynthesis, nutrient and starch contents, mycorrhizal colonization and OsPT11 gene expression were measured. C investment in fungal growth was estimated. Results showed that, in rice, MGR was dependent on AM nutrient uptake effects, namely on the synergy between N and Zn, and not on C expenditure. The supply of C to the fungus was dependent on the plant's nutrient demand, indicated by high shoot C/N or low %N. We conclude that one of the real reasons for the negative MGR of rice, Zn deficiency of AMF plants, would have remained hidden without an experimental design allowing the observation of plants' response to AM along gradients of nutrient concentrations. Adopting more integrative and comprehensive experimental approaches in mycorrhizal studies seems therefore essential if we are to achieve a true understanding of AM function, namely of the mechanisms of C/N exchange regulation in AM. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Nutrients, foods, and colorectal cancer prevention.

    Science.gov (United States)

    Song, Mingyang; Garrett, Wendy S; Chan, Andrew T

    2015-05-01

    Diet has an important role in the development of colorectal cancer. In the past few decades, findings from extensive epidemiologic and experimental investigations have linked consumption of several foods and nutrients to the risk of colorectal neoplasia. Calcium, fiber, milk, and whole grains have been associated with a lower risk of colorectal cancer, and red meat and processed meat have been associated with an increased risk. There is substantial evidence for the potential chemopreventive effects of vitamin D, folate, fruits, and vegetables. Nutrients and foods also may interact, as a dietary pattern, to influence colorectal cancer risk. Diet likely influences colorectal carcinogenesis through several interacting mechanisms. These include the direct effects on immune responsiveness and inflammation, and the indirect effects of overnutrition and obesity-risk factors for colorectal cancer. Emerging evidence also implicates the gut microbiota as an important effector in the relationship between diet and cancer. Dietary modification therefore has the promise of reducing colorectal cancer incidence. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

  20. Using oxidized liquid and solid human waste as nutrients for Chlorella vulgaris and cyanobacterium Oscillatoria deflexa

    Science.gov (United States)

    Trifonov, Sergey V.; Kalacheva, Galina; Tirranen, Lyalya; Gribovskaya, Iliada

    At stationary terrestrial and space stations with closed and partially closed substance exchange not only plants, but also algae can regenerate atmosphere. Their biomass can be used for feeding Daphnia and Moina species, which, in their turn, serve as food for fish. In addition, it is possible to use algae for production of biological fuel. We suggested two methods of human waste mineralization: dry (evaporation with subsequent incineration in a muffle furnace) and wet (oxidation in a reactor using hydrogen peroxide). The research task was to prepare nutrient media for green alga Chlorella vulgaris and cyanobacterium Oscillatoria deflexa using liquid human waste mineralized by dry method, and to prepare media for chlorella on the basis of 1) liquid and 2) liquid and solid human waste mineralized by wet method. The algae were grown in batch culture in a climate chamber with the following parameters: illumination 7 klx, temperature 27-30 (°) C, culture density 1-2 g/l of dry weight. The control for chlorella was Tamiya medium, pH-5, and for oscillstoria — Zarrouk medium, pH-10. Maximum permissible concentrations of NaCl, Cl, urea (NH _{2}) _{2}CO, and native urine were established for algae. Missing ingredients (such as salts and acids) for experimental nutrient media were determined: their addition made it possible to obtain the biomass production not less than that in the control. The estimation was given of the mineral and biochemical composition of algae grown on experimental media. Microbiological test revealed absence of foreign microbial flora in experimental cultures.

  1. Research of the fluorescence detection apparatus for nutrients

    Science.gov (United States)

    Wang, Yu; Yan, Huimin; Ni, Xuxiang; Xu, Xiaoyi; Chen, Shibing

    2015-10-01

    The research of the multifunctional analyzer of Clinical Nutrition, which integrates the absorbance, luminescence, fluorescence and other optical detection methods, can overcome the functional limitations of a single technology on human nutrition analysis, and realize a rapid and accurate analysis of the nutrients. This article focuses on the design of fluorescence detection module that uses a photomultiplier tube(PMT) to detect weak fluorescence, and utilizes the single photon counting method to measure the fluorescence intensity, and then according to the relationship between the fluorescent marker and fluorescence intensity, the concentration of the analyte can be derived. Using fluorescein isothiocyanate(FITC, the most widely used fluorescein currently)to mark antibodies in the experiment, therefore, according to the maximum absorption wavelength and the maximum emission wavelength of the fluorescein isothiocyanate, to select the appropriate filters to set up the optical path. In addition, the fluorescence detection apparatus proposed in this paper uses an aspherical lens with large numerical aperture, in order to improve the capacity of signal acquisition more effectively, and the selective adoption of flexible optical fiber can realize a compact opto-mechanical structure, which is also conducive to the miniaturization of the device. The experimental results show that this apparatus has a high sensitivity, can be used for the detection and analysis of human nutrition.

  2. Multiple constraint modeling of nutrient cycling stoichiometry following forest clearing and pasture abandonment in the Eastern Amazon

    Science.gov (United States)

    Davidson, Eric; Nifong, Rachel

    2017-04-01

    While deforestation has declined since its peak, land-use change continues to modify Amazonian landscapes. The responses and feedbacks of biogeochemical cycles to these changes play an important role in determining possible future trajectories of ecosystem function and for land stewardship through effects on rates of secondary forest regrowth, soil emissions of greenhouse gases, inputs of nutrients to groundwater and streamwater, and nutrient management in agroecosystems. Here we present a new synthetic analyses of data from the NASA-supported LBA-ECO project and others datasets on nutrient cycling in cattle pastures, secondary forests, and mature forests at Paragominas, Pará, Brazil. We have developed a stoichiometric model relating C-N-P interactions during original forest clearing, extensive and intensive pasture management, and secondary forest regrowth, constrained by multiple observations of ecosystem stocks and fluxes in each land use. While P is conservatively cycled in all land uses, we demonstrate that pyrolyzation of N during pasture formation and during additional burns for pasture management depletes available-N pools, consistent with observations of lower rates of N leaching and trace gas emission and consistent with secondary forest growth responses to experimental N amendments. The soils store large stocks of N and P, and our parameterization of available forms of these nutrients for steady-state dynamics in the mature forest yield reasonable estimates of net N and P mineralization available for grasses and secondary forest species at rates consistent with observed biomass accumulation and productivity in these modified ecosystems. Because grasses and forests have much different demands for N relative to P, the land use has important biogeochemical impacts. The model demonstrates the need for periodic P inputs for sustainable pasture management and for a period of significant biological N fixation for early-to-mid-successional secondary forest

  3. The stoichiometry of nutrient release by terrestrial herbivores and its ecosystem consequences

    Science.gov (United States)

    Sitters, Judith; Bakker, Elisabeth S.; Veldhuis, Michiel P.; Veen, G. F.; Olde Venterink, Harry; Vanni, Michael J.

    2017-04-01

    It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N) and phosphorus (P) recycled through herbivore release (i.e., waste N:P) are mainly determined by the stoichiometric composition of the herbivore’s food (food N:P) and its body nutrient content (body N:P). Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C ):N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces) and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

  4. Are large macroalgal blooms necessarily bad? Nutrient impacts on seagrass in upwelling-influenced estuaries.

    Science.gov (United States)

    Hessing-Lewis, Margot L; Hacker, Sally D; Menge, Bruce A; McConville, Sea-oh; Henderson, Jeremy

    2015-07-01

    Knowledge of nutrient pathways and their resulting ecological interactions can alleviate numerous environmental problems associated with nutrient increases in both natural and managed systems. Although not unique, coastal systems are particularly prone to complex ecological interactions resulting from nutrient inputs from both the land and sea. Nutrient inputs to coastal systems often spur ulvoid macroalgal blooms, with negative consequences for seagrasses, primarily through shading, as well as through changes in local biogeochemistry. We conducted complementary field and mesocosm experiments in an upwelling-influenced estuary, where marine-derived nutrients dominate, to understand the direct and indirect effects of nutrients on the macroalgal-eelgrass (Zostera marina L.) interaction. In the field experiment, we found weak evidence that nutrients and/or macroalgal treatments had a negative effect on eelgrass. However, in the mesocosm experiment, we found that a combination of nutrient and macroalgal treatments led to strongly negative eelgrass responses, primarily via indirect effects associated with macroalgal additions. Together, increased total light attenuation and decreased sediment oxygen levels were associated with larger effects on eelgrass than shading alone, which was evaluated using mimic algae treatments that did not alter sediment redox potential. Nutrient addition in the mesocosms directly affected seagrass density; biomass, and morphology, but not as strongly as macroalgae. We hypothesize that the contrary results from these parallel experiments are a consequence of differences in the hydrodynamics between field and mesocosm settings. We suggest that the high rates of water movement and tidal submersion of our intertidal field experiments alleviated the light reduction and negative biogeochemical changes in the sediment associated with macroalgal canopies, as well as the nutrient effects observed in the mesocosm experiments. Furthermore, adaptation

  5. Nutrient feedbacks to soil heterotrophic nitrogen fixation in forests

    Science.gov (United States)

    Perakis, Steven; Pett-Ridge, Julie C.; Catricala, Christina E.

    2017-01-01

    Multiple nutrient cycles regulate biological nitrogen (N) fixation in forests, yet long-term feedbacks between N-fixation and coupled element cycles remain largely unexplored. We examined soil nutrients and heterotrophic N-fixation across a gradient of 24 temperate conifer forests shaped by legacies of symbiotic N-fixing trees. We observed positive relationships among mineral soil pools of N, carbon (C), organic molybdenum (Mo), and organic phosphorus (P) across sites, evidence that legacies of symbiotic N-fixing trees can increase the abundance of multiple elements important to heterotrophic N-fixation. Soil N accumulation lowered rates of heterotrophic N-fixation in organic horizons due to both N inhibition of nitrogenase enzymes and declines in soil organic matter quality. Experimental fertilization of organic horizon soil revealed widespread Mo limitation of heterotrophic N-fixation, especially at sites where soil Mo was scarce relative to C. Fertilization also revealed widespread absence of P limitation, consistent with high soil P:Mo ratios. Responses of heterotrophic N-fixation to added Mo (positive) and N (negative) were correlated across sites, evidence that multiple nutrient controls of heterotrophic N-fixation were more common than single-nutrient effects. We propose a conceptual model where symbiotic N-fixation promotes coupled N, C, P, and Mo accumulation in soil, leading to positive feedback that relaxes nutrient limitation of overall N-fixation, though heterotrophic N-fixation is primarily suppressed by strong negative feedback from long-term soil N accumulation.

  6. A dual porosity model of nutrient uptake by root hairs

    KAUST Repository

    Zygalakis, K. C.

    2011-08-09

    Summary: • The importance of root hairs in the uptake of sparingly soluble nutrients is understood qualitatively, but not quantitatively, and this limits efforts to breed plants tolerant of nutrient-deficient soils. • Here, we develop a mathematical model of nutrient uptake by root hairs allowing for hair geometry and the details of nutrient transport through soil, including diffusion within and between soil particles. We give illustrative results for phosphate uptake. • Compared with conventional \\'single porosity\\' models, this \\'dual porosity\\' model predicts greater root uptake because more nutrient is available by slow release from within soil particles. Also the effect of soil moisture is less important with the dual porosity model because the effective volume available for diffusion in the soil is larger, and the predicted effects of hair length and density are different. • Consistent with experimental observations, with the dual porosity model, increases in hair length give greater increases in uptake than increases in hair density per unit main root length. The effect of hair density is less in dry soil because the minimum concentration in solution for net influx is reached more rapidly. The effect of hair length is much less sensitive to soil moisture. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  7. Nutrient limitation of terrestrial free-living nitrogen fixation.

    Science.gov (United States)

    Dynarski, Katherine A; Houlton, Benjamin Z

    2018-02-01

    Nitrogen (N) fixation by free-living bacteria is a primary N input pathway in many ecosystems and sustains global plant productivity. Uncertainty exists over the importance of N, phosphorus (P) and molybdenum (Mo) availability in controlling free-living N fixation rates. Here, we investigate the geographic occurrence and variability of nutrient constraints to free-living N fixation in the terrestrial biosphere. We compiled data from studies measuring free-living N fixation in response to N, P and Mo fertilizers. We used meta-analysis to quantitatively determine the extent to which N, P and Mo stimulate or suppress N fixation, and if environmental variables influence the degree of nutrient limitation of N fixation. Across our compiled dataset, free-living N fixation is suppressed by N fertilization and stimulated by Mo fertilization. Additionally, free-living N fixation is stimulated by P additions in tropical forests. These findings suggest that nutrient limitation is an intrinsic property of the biochemical demands of N fixation, constraining free-living N fixation in the terrestrial biosphere. These findings have implications for understanding the causes and consequences of N limitation in coupled nutrient cycles, as well as modeling and forecasting nutrient controls over carbon-climate feedbacks. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  8. Nutrient resorption from seagrass leaves

    NARCIS (Netherlands)

    Stapel, J.; Hemminga, M.A.

    1997-01-01

    The resorption of nutrients (C, N and P) from senescent leaves of six seagrass species from nine different locations in tropical (Indonesia and Kenya), Mediterranean (Spain) and temperate (The Netherlands) regions has been investigated. Resorption was quantitatively assessed by calculating the

  9. Nutrients for the aging eye

    Directory of Open Access Journals (Sweden)

    Rasmussen HM

    2013-06-01

    Full Text Available Helen M Rasmussen,1 Elizabeth J Johnson2 1Educational Studies, Lesley University, Cambridge, MA, USA; 2Carotenoid and Health Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA Abstract: The incidence of age-related eye diseases is expected to rise with the aging of the population. Oxidation and inflammation are implicated in the etiology of these diseases. There is evidence that dietary antioxidants and anti-inflammatories may provide benefit in decreasing the risk of age-related eye disease. Nutrients of interest are vitamins C and E, β-carotene, zinc, lutein, zeaxanthin, and the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid. While a recent survey finds that among the baby boomers (45–65 years old, vision is the most important of the five senses, well over half of those surveyed were not aware of the important nutrients that play a key role in eye health. This is evident from a national survey that finds that intake of these key nutrients from dietary sources is below the recommendations or guidelines. Therefore, it is important to educate this population and to create an awareness of the nutrients and foods of particular interest in the prevention of age-related eye disease. Keywords: nutrition, aging, eye health

  10. Recycling nutrients in algae biorefinery

    NARCIS (Netherlands)

    Garcia Alba, Laura; Vos, M.P.; Torri, C.; Fabbri, D.; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2013-01-01

    Algal fuel cells: Repeated nutrient recycling is demonstrated by reusing the aqueous phase obtained from the hydrothermal liquefaction (HTL) of microalgae. This is achieved, for the first time, by performing a complete set of four continuous growth–HTL cycles. Results show similar growth rates in

  11. integrated soil nutrient management option for sustainable yam ...

    African Journals Online (AJOL)

    Also when yam followed pigeon pea, the cost benefit ratio showed that Gh 1.00 farmer investment in yam production resulted a profit of Gh 1.65 and Gh 2.22 in addition to the Gh 1.00 invested capital for both Fumesua and. Ejura communities respectively. The study suggests integrated nutrient management approach with.

  12. Effect of organic nutrient on microbial utilization of hydrocarbons on ...

    African Journals Online (AJOL)

    Administrator

    2006-05-16

    May 16, 2006 ... (ii), (iii), and (iv), respectively. The results of the study suggest that addition of organic nutrient. (especially 90 g poultry manure) will further enhance microbial utilization of hydrocarbons. Key words: Biodegradation, crude oil, poultry manure. INTRODUCTION. The petroleum industry has created economic ...

  13. Effects of Soy-based allochthonous nutrient inputs on intensively ...

    African Journals Online (AJOL)

    hope&shola

    reproductive success (Adewumi, 2005). Culturing C. gariepinus broodstock intensively require continuous introduction of highly nutritious artificial feed into the culture system. Systematic addition of artificial feed and subsequent nutrient leaching from it as well as microbial decomposition of uneaten feeds and feacal matters ...

  14. Plant community development is affected by nutrients and soil biota

    NARCIS (Netherlands)

    De Deyn, G.B.; Raaijmakers, C.E.; Van der Putten, W.H.

    2004-01-01

    1 Plant community development depends to a great extent on the availability of soil nutrients, but recent studies underline the role of symbiotic, herbivorous and pathogenic soil biota. We tested for interactions between these biotic and abiotic factors by studying the effects of additional

  15. Water and nutrient management in natural and constructed wetlands

    National Research Council Canada - National Science Library

    Vymazal, Jan

    2010-01-01

    ... are also used in constructed wetlands for wastewater treatment but within a more controlled environment. In addition, wetlands provide the supporting services necessary for the production of all other ecosystem services such as soil formation and retention, nutrient cycling, primary production or water cycling. In short, wetlands are clearly among t...

  16. Plant communtiy development is affected by nutrients and soil biota

    NARCIS (Netherlands)

    Deyn, de G.B.; Raaijmakers, C.E.; Putten, van der W.H.

    2004-01-01

    1 Plant community development depends to a great extent on the availability of soil nutrients, but recent studies underline the role of symbiotic, herbivorous and pathogenic soil biota. We tested for interactions between these biotic and abiotic factors by studying the effects of additional

  17. Energy and nutrient utilisation by embryonic reptiles.

    Science.gov (United States)

    Thompson, Michael B; Speake, Brian K

    2002-11-01

    Most reptiles are oviparous, with the developing embryos relying on the contents of the yolk to sustain development until hatching (lecithotrophy). The yolk is composed primarily of lipid and protein, which act as an energy source and the essential components to build embryonic tissue. Nevertheless, yolk and the resulting embryos contain many other nutrients, including inorganic ions, vitamins, carotenoids, water and hormones. Apart from water and oxygen, which may be taken up by eggs, and some inorganic ions that can come from the eggshell or even from outside the egg, everything required by the embryo must be in the egg when it is laid. Approximately 20% of squamate reptiles are viviparous, exhibiting a variety of placental complexities. Species with complex placentae have reduced yolk volumes, with the mother augmenting embryonic nutrition by provision across the placenta (placentotrophy). Despite assumed advantages of placentotrophy, only 5 out of approximately 100 lineages of viviparous squamates exhibit substantial placentotrophy. This paper reviews available and recent information on the yolk contents of a variety of squamate reptiles to ask the question, how are nutrients transported from the yolk to the embryo or across the placenta? Although, current available data suggest that, in broad terms, yolk is taken up by embryos without discrimination of the nutrients, there are some apparent exceptions, including the very long chain polyunsaturated fatty acids. In addition, fundamental differences in the patterns of energy utilisation in lizards and snakes suggest fundamental differences in lipid profiles in these taxa, which appear to reflect the differences between placentotrophic and lecithotrophic viviparous lizards.

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

    Directory of Open Access Journals (Sweden)

    Kevin B. Comerford

    2015-07-01

    Full Text Available 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.

  19. Combined nutrient and macroalgae loads lead to response in seagrass indicator properties

    NARCIS (Netherlands)

    Han, Q.Y.; Soissons, L.M.; Bouma, T.J.; van Katwijk, M.M.; Liu, D.

    2016-01-01

    Excess nutrients are potential factors that drive phase shifts fromseagrasses to macroalgae.We carried out a manipulativefield experiment to study the effects of macroalgae Ulva pertusa loading and nutrient addition to thewater column on the nitrogen (N) and carbon (C) contents (i.e., fast

  20. Seagrass Epiphytes as a Nutrient Stressor Indicator: Towards Development of Threshold Values

    Science.gov (United States)

    Epiphytes on seagrasses have been studied for more than 50 years, and proposed as an indicator of anthropogenic nutrient enrichment for over 30 years. Epiphytes have been correlated with seagrass declines, causally related to nutrient additions in both field and mesocosm experim...

  1. SEAGRASS EPIPHYTES AS A NUTRIENT STRESSOR INDICATOR: APPROACHES TOWARDS DEVELOPMENT OF THRESHOLD VALUES.

    Science.gov (United States)

    Epiphytes on seagrasses have been studied for more than 50 years, and proposed as an indicator of anthropogenic nutrient enrichment for over 30 years. Epiphytes have been correlated with seagrass declines, causally related to nutrient additions in both field and mesocosm experim...

  2. Ecosystem-Scale Effects of Nutrients and Fishing on Coral Reefs

    Directory of Open Access Journals (Sweden)

    Sheila M. Walsh

    2011-01-01

    Full Text Available Nutrient pollution and fishing are the primary local causes of coral reef decline but their ecosystem-scale effects are poorly understood. Results from small-scale manipulative experiments of herbivores and nutrients suggest prioritizing management of fishing over nutrient pollution because herbivores can control macroalgae and turf in the presence of nutrients. However, ecological theory suggests that the opposite occurs at large scales. Moreover, it is unclear whether fishing decreases herbivores because fishing of predators may result in an increase in herbivores. To investigate this paradox, data on the fish and benthic communities, fishing, and nutrients were collected on Kiritimati, Kiribati. Oceanographic conditions and a population resettlement program created a natural experiment to compare sites with different levels of fishing and nutrients. Contrary to theory, herbivores controlled macroalgae in the presence of nutrients at large spatial scales, and herbivores had greater effects on macroalgae when nutrients were higher. In addition, fishing did not increase herbivores. These results suggest that protecting herbivores may have greater relative benefits than reducing nutrient pollution, especially on polluted reefs. Reallocating fishing effort from herbivores to invertivores or planktivores may be one way to protect herbivores and indirectly maintain coral dominance on reefs impacted by fishing and nutrient pollution.

  3. Sources of nutrients to nearshore areas of a eutrophic estuary: Implications for nutrient-enhanced acidification in Puget Sound

    Science.gov (United States)

    Ocean acidification has recently been highlighted as a major stressor for coastal organisms. Further work is needed to assess the role of anthropogenic nutrient additions in eutrophied systems on local biological processes, and how this interacts with CO2emission-driven acidific...

  4. Nutrient-Sensing Biology in Mammals and Birds

    DEFF Research Database (Denmark)

    Roura, Eugeni; Foster, Simon R

    2018-01-01

    Nutrient sensing mechanisms have emerged as the fringe articulating nutritional needs with dietary choices. Carbohydrate, amino acid, fatty acid, mineral, and water sensing receptors are highly conserved across mammals and birds, consisting of a repertoire of 22 genes known to date. In contrast......, bitter receptors are highly divergent and have a high incidence of polymorphisms within and between mammals and birds and are involved in the adaptation of species to specific environments. In addition, the expression of nutrient sensing genes outside the oral cavity seems to mediate the required...

  5. Nutrient and energy recovery from urine

    NARCIS (Netherlands)

    Kuntke, P.

    2013-01-01

    Keywords: urine, urine treatment, nutrient recovery, microbial fuel cells, energy production from urine, membrane capacitive deionization. In conventional wastewater treatment plants large amounts of energy are required for the removal and recovery of nutrients (i.e. nitrogen and phosphorus).

  6. Vitamins and Other Nutrients during Pregnancy

    Science.gov (United States)

    ... weight & fitness > Vitamins and other nutrients during pregnancy Vitamins and other nutrients during pregnancy E-mail to ... supplements without your provider’s OK. What are prenatal vitamins? Prenatal vitamins are multivitamins made just for pregnant ...

  7. Reduction of mineral nutrient availability accelerates flowering of Arabidopsis thaliana.

    Science.gov (United States)

    Kolár, Jan; Senková, Jana

    2008-10-09

    The time of flowering is regulated by various environmental cues, and in some plant species, it is known to be affected by abiotic stresses. We investigated the effect of nutrient stress caused by an abrupt reduction of mineral nutrition on flowering of Arabidopsis thaliana. We used a hydroponic culture system that enabled us to precisely control nutrient levels. When plants were grown in full-strength nutrient solution for several weeks and then transferred to a diluted medium, the time from sowing to bud appearance was significantly shortened. This acceleration of flowering was more pronounced in short days than in long days, and stronger in the ecotype Landsberg erecta than in Columbia and San Feliu-2. The response was also affected by the age of plants at the beginning of nutrient stress and by the concentration of the diluted medium: earlier treatment and more diluted solutions strengthened the effect. Flowering was affected by nutrient stress, not by a change in the osmotic potential of the medium: addition of mannitol to a 1000-fold diluted solution had no effect on the promotion of flowering. When 3-week-old Landsberg erecta plants were exposed to 1000-fold diluted nutrient solution in an 8-h day length, flower bud appearance was strongly and reproducibly advanced by 10.8-12.8d compared with control plants (which developed buds 41.1-46.2d after sowing). This treatment can serve as an optimized protocol for future studies concerning physiological, molecular and ecological aspects of flower induction by nutrient stress in A. thaliana.

  8. Can nutrient enrichment influence the invasion of Phragmites australis?

    Science.gov (United States)

    Uddin, Md Nazim; Robinson, Randall William

    2018-02-01

    Plant invasion and nutrient enrichment because of anthropogenic landscape modifications seriously threaten native plant community diversity in aquatic and wetland ecosystems. It is poorly understood, however, whether these two disturbances interact with the functional identity of recipient native plants to drive community change. We performed combined studies in the fields and greenhouse to examine whether nutrient enrichment may trigger the invasion of Phragmites australis in wetlands through competitive advantage over native Melaleuca ericifolia. Chemical characterizations of rhizosphere water were distinguished in two different nutrient enriched wetlands associated with and without Phragmites over the seasons. Significant changes in rhizosphere water were observed in invaded area compared to uninvaded area at both sites. High nitrogen (NO3-), phosphorous (PO43-), dissolved organic carbon, phenolics contents, with low pH were found in invaded areas compared to uninvaded areas. Total biomass of Phragmites was positively regressed with rhizosphere water nitrogen (NO3-) and phosphorous (PO43-) content. Nutrient addition significantly enhanced the growth and competitive ability of Phragmites over Melaleuca. In contrast, Melaleuca was significantly less competitive than Phragmites. There was a significantly positive correlation between the growth of Phragmites grown alone and its competitive ability. The findings in greenhouse studies coupled with characteristics of Phragmites and its' rhizosphere chemistry in the nutrient enriched fields suggest that nutrient enrichment may enhance Phragmites invasion through correspondingly increasing growth and maintaining inherent competitive advantages of Phragmites. Nutrient management could limit the vigorous growth of Phragmites in wetlands and thereby reduce invasion through competitive advantages over natives, which might have important management implications for wetland managers. Copyright © 2017. Published by Elsevier B.V.

  9. Interactions between soil texture, water, and nutrients control patterns of biocrusts abundance and structure

    Science.gov (United States)

    Young, Kristina; Bowker, Matthew; Reed, Sasha; Howell, Armin

    2017-04-01

    Heterogeneity in the abiotic environment structures biotic communities by controlling niche space and parameters. This has been widely observed and demonstrated in vascular plant and other aboveground communities. While soil organisms are presumably also strongly influenced by the physical and chemical dimensions of the edaphic environment, there are fewer studies linking the development, structure, productivity or function of surface soil communities to specific edaphic gradients. Here, we use biological soil crusts (biocrusts) as a model system to determine mechanisms regulating community structure of soil organisms. We chose soil texture to serve as an edaphic gradient because of soil texture's influence over biocrust distribution on a landscape level. We experimentally manipulated texture in constructed soil, and simultaneously manipulated two main outcomes of texture, water and nutrient availability, to determine the mechanism underlying texture's influence on biocrust abundance and structure. We grew biocrust communities from a field-sourced inoculum on four different soil textures, sieved from the same parent soil material, manipulating watering levels and nutrient additions across soil textures in a full-factorial design over a 5-month period of time. We measured abundance and structure of biocrusts over time, and measured two metrics of function, N2 fixation rates and soil stabilization, at the conclusion of the experiment. Our results showed finer soil textures resulted in faster biocrust community development and dominance by mosses, whereas coarser textures grew more slowly and had biocrust communities dominated by cyanobacteria and lichen. Additionally, coarser textured soils contained cyanobacterial filaments significantly deeper into the soil profile than fine textured soils. N2-fixation values increased with increasing moss cover and decreased with increasing cyanobacterial cover, however, the rate of change depended on soil texture and water amount

  10. Lichen substances prevent lichens from nutrient deficiency.

    Science.gov (United States)

    Hauck, Markus; Willenbruch, Karen; Leuschner, Christoph

    2009-01-01

    The dibenzofuran usnic acid, a widespread cortical secondary metabolite produced by lichen-forming fungi, was shown to promote the intracellular uptake of Cu(2+) in two epiphytic lichens, Evernia mesomorpha and Ramalina menziesii, from acidic, nutrient-poor bark. Higher Cu(2+) uptake in the former, which produces the depside divaricatic acid in addition to usnic acid, suggests that this depside promotes Cu(2+) uptake. Since Cu(2+) is one of the rarest micronutrients, promotion of Cu(2+) uptake by lichen substances may be crucial for the studied lichens to survive in their nutrient-poor habitats. In contrast, study of the uptake of other metals in E. mesomorpha revealed that the intracellular uptake of Mn(2+), which regularly exceeds potentially toxic concentrations in leachates of acidic tree bark, was partially inhibited by the lichen substances produced by this species. Inhibition of Mn(2+) uptake by lichen substances previously has been demonstrated in lichens. The uptake of Fe(2+), Fe(3+), Mg(2+), and Zn(2+), which fail to reach toxic concentrations in acidic bark at unpolluted sites, although they are more common than Cu(2+), was not affected by lichen substances of E. mesomorpha.

  11. Nutrient availability as a control of the abundance and activities of deep subsurface microorganisms. Final report, June 30, 1991--June 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Ghiorse, W.C.

    1992-12-31

    The focus of our research is to determine whether the availability of major nutrients (C, N, P) control the abundance, distribution, and activity of heterotrophic microorganisms in subsurface sediments. Specifically we have developed and are testing a microcosm system using subsurface sediment samples from a DOE site. We are using this system to conduct a preliminary nutrient enrichment experiments. The flow-through microcosm system simulates conditions in natural aquifers and can be regulated with respect to water flow rate, temperature, oxygen concentration, and nutrient concentration. Furthermore, the system cam be run aseptically, excluding exogenous bacteria from test cores. In our preliminary nutrient enrichment experiment, we collected deep vadose sediment from the Savannah River Site and pumped sterilized well water from sampling area through microcosms that were filled with this sediment. Experimental treatments included the flow-through of this water amen with different combinations of nutrients (+N+P, +C, +N+P+C) or no additional nutrients. We found that asepsis was maintained for the entire 30 day experiment. We also found that microbial abundance, biomass, and activity increased in several microcosms in response to the flow through of the well water, which was rich in nitrate. This response, however, was variable among both microcosms containing intact sediments and microcosms containing intact sediment core sections. No significant treatment responses were observed, but each microcosm that had an increase in microbial growth also immobilized N from the well water. We infer that water and N availability, and water table fluctuations strongly influence microbial growth and activity in the deep vadose.

  12. Nutrient adequacy of a very low-fat vegan diet.

    Science.gov (United States)

    Dunn-Emke, Stacey R; Weidner, Gerdi; Pettengill, Elaine B; Marlin, Ruth O; Chi, Christine; Ornish, Dean M

    2005-09-01

    This study assessed the nutrient adequacy of a very low-fat vegan diet. Thirty-nine men (mean age=65 years) with early stage prostate cancer who chose the "watchful waiting" approach to disease management, were instructed by a registered dietitian and a chef on following a very low-fat (10%) vegan diet with the addition of a fortified soy protein powdered beverage. Three-day food diaries, excluding vitamin and mineral supplements, were analyzed and nutrient values were compared against Dietary Reference Intakes (DRI). Mean dietary intake met the recommended DRIs. On the basis of the Adequate Intake standard, a less than adequate intake was observed for vitamin D. This demonstrates that a very low-fat vegan diet with comprehensive nutrition education emphasizing nutrient-fortified plant foods is nutritionally adequate, with the exception of vitamin D. Vitamin D supplementation, especially for those with limited sun exposure, can help assure nutritional adequacy.

  13. Short Communication Preliminary Studies on Nutrients Removal ...

    African Journals Online (AJOL)

    Short Communication Preliminary Studies on Nutrients Removal Potential of Selected Aquatic Plants. ... Aquatic plants can remove nutrients (P&N) from sewage or industrial wastewater through accumulation. ... This study had identified some aquatic plants as good potential nutrient removers especially in wetlands.

  14. Modeling global nutrient export from watersheds

    NARCIS (Netherlands)

    Kroeze, C.; Bouwman, A.F.; Seitzinger, S.

    2012-01-01

    We describe how global models can be used to analyze past and future trends in nutrient export from watersheds and how such models can be used to analyze causes and effects of coastal eutrophication. Future nutrient inputs to coastal waters may be higher than today, and nutrient ratios may depart

  15. Nutrient quality of fast food kids meals

    Science.gov (United States)

    Exposure of children to kids’ meals at fast food restaurants is high; however, the nutrient quality of such meals has not been systematically assessed. We assessed the nutrient quality of fast food meals marketed to young children, i.e., "kids meals". The nutrient quality of kids’ meals was assessed...

  16. Benchmarking nutrient use efficiency of dairy farms

    NARCIS (Netherlands)

    Mu, W.; Groen, E.A.; Middelaar, van C.E.; Bokkers, E.A.M.; Hennart, S.; Stilmant, D.; Boer, de I.J.M.

    2017-01-01

    The nutrient use efficiency (NUE) of a system, generally computed as the amount of nutrients in valuable outputs over the amount of nutrients in all inputs, is commonly used to benchmark the environmental performance of dairy farms. Benchmarking the NUE of farms, however, may lead to biased

  17. Nutrient behaviour in urban drainages

    OpenAIRE

    Choy, David Kam Wai

    2017-01-01

    Urbanisation has altered the natural landscape, removing features that previously acted to retain, transform and process nitrogen and phosphorus within catchments. In Melbourne the past legacy of traditional urban design aimed at efficient drainage of stormwater has resulted in higher stormwater volumes with high pollutant concentrations. Excessive concentrations of such nutrients in urban runoff can have an adverse impact on the ecological health of receiving waters. The aims of this stu...

  18. The European Nutrient Database (ENDB) for nutritional epidemiology

    DEFF Research Database (Denmark)

    Charrondiere, U.R.; Vignat, J.; Møller, Anni Rosendal

    2002-01-01

    Food composition databases (FCDB), as well as standardized calculation procedures are required for international studies on nutrition and disease to calculate nutrient intakes across countries. Comparisons of national FCDBs have shown that major improvements are needed in standardization and docu......Food composition databases (FCDB), as well as standardized calculation procedures are required for international studies on nutrition and disease to calculate nutrient intakes across countries. Comparisons of national FCDBs have shown that major improvements are needed in standardization...... a standardized and critically assessed nutrient database for the 10 countries involved in the European Prospective Investigation into Cancer and Nutrition (EPIC): Denmark, France, Germany, Greece, Great Britain, Italy, The Netherlands, Norway, Spain and Sweden. It will be compiled using the general concept...... Nutrient Database (ENDB) will contain values for approximately 100 nutrients for 1000 foods per country, which is mainly derived from EPIC consumption data. In the future, this database could be extended to include more foods, components and countries. Additionally, methodological issues should...

  19. Sweet potato for closed ecological life support systems using the nutrient film technique

    Science.gov (United States)

    Loretan, P. A.; Hill, W. A.; Bonsi, C. K.; Morris, C. E.; Lu, J. Y.; Ogbuehi, C. R. A.; Mortley, D. G.

    1990-01-01

    Sweet potatoes were grown hydroponically using the nutrient film technique (NFT) in support of the Closed Ecological Life Support System (CELSS) program. Experiments in the greenhouse with the TI-155 sweet potato cultivar produced up to 1790 g/plant of fresh storage roots. Studies with both TI-155 and Georgia Jet cultivars resulted in an edible biomass index of approximately 60 percent, with edible biomass linear growth rates of 12.1 to 66.0 g m(exp -2)d(exp -1) in 0.05 to 0.13 sq meters in 105 to 130 days. Additional experimental results are given. All studies indicate good potential for sweet potatoes in CELSS.

  20. Yield and nutrition of tomato using different nutrient sources Produção e nutrição do tomateiro com diferentes fontes de nutrientes

    Directory of Open Access Journals (Sweden)

    SN Zuba

    2011-03-01

    Full Text Available The effect of alternative sources of nutrients was evaluated on yield, nutrition and fruit quality of tomato cv Santa Clara in an agro ecological system, under natural conditions in Montes Claros, Minas Gerais State, Brazil. The experimental design was of completely randomized blocks with seven treatments and four replications, using eight plants per experimental plot. The treatments comprised of 1 conventional fertilization with NPK; 2 organic compost + natural phosphate + rock dust, applied separately; 3 organic compost produced from the addition of natural phosphate and rock dust + green manure; 4 organic compost produced from the addition of rock dust + natural phosphate + green manure; 5 organic compost produced from the addition of natural phosphate and rock dust + green manure; 6 natural phosphate + rock dust; and 7 organic compost + natural phosphate + rock dust + green manure. The highest production was obtained using chemical fertilizers. There was no difference among the treatments regarding the content of foliar nutrients and fruit diameter, pH and total soluble solids. The use of mineral and organic fertilizers significantly reduced the incidence of soft rot and pests in comparison to the use of chemical fertilizers.Com o objetivo de analisar fontes alternativas de nutrientes na produtividade, nutrição e qualidade dos frutos do tomateiro (Lycopersicon esculentum cv Santa Clara, em sistema agroecológico, no período chuvoso, de setembro a janeiro, conduziu-se um experimento, em condições de campo, no município de Montes Claros-MG. O delineamento experimental foi de blocos ao acaso, com sete tratamentos e quatro repetições. Os tratamentos foram 1 adubação convencional, com NPK; 2 composto orgânico + fosfato natural + pó-de-rocha, aplicados separadamente; 3 composto orgânico, produzido com a adição de fosfato natural e pó-de-rocha + adubação verde; 4 composto orgânico, produzido com pó-de-rocha + fosfato natural

  1. Evidence for sensitivity of dune wetlands to groundwater nutrients.

    Science.gov (United States)

    Rhymes, Jennifer; Wallace, Hilary; Fenner, Nathalie; Jones, Laurence

    2014-08-15

    Dune slacks are seasonal wetlands, high in biodiversity, which experience considerable within-year and between-year variations in water-table. They are subject to many pressures including climate change, land use change and eutrophication. Despite their biological importance and the threats facing them, the hydrological and nutrient parameters that influence their soil properties and biodiversity are poorly understood and there have been no empirical studies to date testing for biological effects in dune systems resulting from groundwater nutrients at low concentrations. In this study we examined the impact of groundwater nutrients on water chemistry, soil chemistry and vegetation composition of dune slacks at three distance classes (0-150 m, 150-300 m, 300-450 m) away from known (off-site) nutrient sources at Aberffraw dunes in North Wales, whilst accounting for differences in water-table regime. Groundwater nitrate and dissolved inorganic nitrogen (DIN) and soil nitrate and nitrite all had significantly higher concentrations closest to the nutrient source. Multivariate analysis showed that although plant species composition within this site was primarily controlled by water table depth and water table fluctuation, nitrogen from groundwater also influenced species composition, independently of water table and soil development. A model containing all hydrological parameters explained 17% of the total species variance; an additional 7% was explained following the addition of NO3 to this model. Areas exposed to elevated, but still relatively low, groundwater nutrient concentrations (mean 0.204 mg/L+/-0.091 of DIN) had greater abundance of nitrophilous species and fewer basipholous species than in areas with lower concentrations. This shows that clear biological impact occurs below previously suggested DIN thresholds of 0.20-0.40 (mg/L). Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Indução do enraizamento e crescimento do eucalipto por rizobactérias: efeito da adição de fonte alimentar e da composição do substrato de enraizamento Rooting induction and growth of eucalyptus by rhizobacteria: effect of addition of nutrient source and growing substrate composition

    Directory of Open Access Journals (Sweden)

    Reginaldo Gonçalves Mafia

    2007-08-01

    Full Text Available Neste trabalho, objetivou-se avaliar o efeito de leite em pó como fonte alimentar e do tipo de substrato sobre a indução biológica do enraizamento e crescimento de mudas clonais de eucalipto por isolados de rizobactérias. Para o primeiro objetivo, após a aplicação dos isolados de rizobactérias, na proporção de 0,2 ml/cc de substrato de uma suspensão de inóculo ajustada para 10(8 u.f.c./ml, enriquecidos ou não com leite em pó (1%, e decorridos 25 dias do estaqueamento de três clones de eucalipto, avaliaram-se a biomassa seca de raízes e o índice de enraizamento de cada combinação isolado-clone. Para o segundo objetivo, 10 isolados, aplicados na mesma proporção e concentração de inóculos citados anteriormente, foram testados em três substratos de enraizamento: vermiculita pura; moinha de carvão + composto de casca de eucalipto + vermiculita (5:3:1; e composto de casca de arroz carbonizada + vermiculita (1:1, em dois ensaios conduzidos com um clone de eucalipto. Os resultados evidenciaram que a aplicação dos isolados promotores de crescimento proporcionou incrementos significativos na velocidade e índice de enraizamento, bem como no crescimento, expresso pela biomassa radicular, cujos ganhos foram superiores, na aplicação com veiculação da fonte alimentar inicial. Dentre os isolados testados, S1 e 3918 (ambos Bacillus subtilis foram os mais efetivos para enraizamento e biomassa radicular, com incrementos de 40,6 e 114,2%, respectivamente. Além disso, não ocorreu interação entre isolados de rizobactérias e substrato de enraizamento, o que permite a utilização desses isolados, independentemente do tipo de substrato empregado.This work aimed to evaluate the effect of powdered milk as a nutrient source and the effect of the substrate composition on the biological rooting induction and minicutting growth by rhizobacteria isolates. A suspension of rhizobacteria (10(8 cfu/ml was used to achieve a concentration of 0

  3. Multiple independent constraints help resolve net ecosystem carbon exchange under nutrient limitation

    Science.gov (United States)

    Thornton, P. E.; Metcalfe, D.; Oren, R.; Ricciuto, D. M.

    2014-12-01

    The magnitude, spatial distribution, and variability of land net ecosystem exchange of carbon (NEE) are important determinants of the trajectory of atmospheric carbon dioxide concentration. Independent observational constraints provide important clues regarding NEE and its component fluxes, with information available at multiple spatial scales: from cells, to leaves, to entire organisms and collections of organisms, to complex landscapes and up to continental and global scales. Experimental manipulations, ecosystem observations, and process modeling all suggest that the components of NEE (photosynthetic gains, and respiration and other losses) are controlled in part by the availability of mineral nutrients, and that nutrient limitation is a common condition in many biomes. Experimental and observational constraints at different spatial scales provide a complex and sometimes puzzling picture of the nature and degree of influence of nutrient availability on carbon cycle processes. Photosynthetic rates assessed at the cellular and leaf scales are often higher than the observed accumulation of carbon in plant and soil pools would suggest. We infer that a down-regulation process intervenes between carbon uptake and plant growth under conditions of nutrient limitation, and several down-regulation mechanisms have been hypothesized and tested. A recent evaluation of two alternative hypotheses for down-regulation in the light of whole-plant level flux estimates indicates that some plants take up and store extra carbon, releasing it to the environment again on short time scales. The mechanism of release, either as additional autotrophic respiration or as exudation belowground is unclear, but has important consequences for long-term ecosystem state and response to climate change signals. Global-scale constraints from atmospheric concentration and isotopic composition data help to resolve this question, ultimately focusing attention on land use fluxes as the most uncertain

  4. Short-term effect of nutrient availability and rainfall distribution on biomass production and leaf nutrient content of savanna tree species.

    Directory of Open Access Journals (Sweden)

    Eduardo R M Barbosa

    Full Text Available Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use. Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall and nutrient availability (no fertilisation vs. fertilisation affects seedlings' above-ground biomass production and leaf-nutrient concentrations (N, P and K of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf

  5. Short-term effect of nutrient availability and rainfall distribution on biomass production and leaf nutrient content of savanna tree species.

    Science.gov (United States)

    Barbosa, Eduardo R M; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T; van Langevelde, Frank

    2014-01-01

    Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall) and nutrient availability (no fertilisation vs. fertilisation) affects seedlings' above-ground biomass production and leaf-nutrient concentrations (N, P and K) of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf nutrient concentration

  6. Nutrient enrichment effects on photosynthesis in the wetland plants Typha orientalis and Phormium tenax

    DEFF Research Database (Denmark)

    Sorrell, Brian Keith; Brix, Hans; Tanner, Chris

    Anthropogenic nutrient enrichment can allow fast-growing species with high photosynthetic capacity to out-compete less vigorous species in freshwater wetlands. We compared the effect of nutrient enrichment on photosynthetic gas exchange in two tall canopy dominants, the inherently fast-growing sp......Anthropogenic nutrient enrichment can allow fast-growing species with high photosynthetic capacity to out-compete less vigorous species in freshwater wetlands. We compared the effect of nutrient enrichment on photosynthetic gas exchange in two tall canopy dominants, the inherently fast......, whereas for flax it was due to lower stomatal conductance in field plants than experimental plants. The differences in photosynthetic physiology between these two species suggest a clear mechanism for the dominance of raupo over morphologically similar species in wetlands subject to nutrient enrichment....... The maximum photosynthetic rates achieved by raupo in this study (up to 60 µmolCO2 m-2 s-1) are amongst the highest ever recorded for C3 plants....

  7. The effect of pH on phosphorus availability and speciation in an aquaponics nutrient solution.

    Science.gov (United States)

    Cerozi, Brunno da Silva; Fitzsimmons, Kevin

    2016-11-01

    The interaction between the main ions in aquaponics nutrient solutions affects chemical composition and availability of nutrients, and nutrient uptake by plant roots. This study determined the effect of pH on phosphorus (P) speciation and availability in an aquaponics nutrient solution and used Visual MINTEQ to simulate P species and P activity. In both experimental and simulated results, P availability decreased with increase in pH of aquaponics nutrient solutions. According to simulations, P binds to several cations leaving less free phosphate ions available in solution. High pH values resulted in the formation of insoluble calcium phosphate species. The study also demonstrated the importance of organic matter and alkalinity in keeping free phosphate ions in solution at high pH ranges. It is recommended though that pH in aquaponics systems is maintained at a 5.5-7.2 range for optimal availability and uptake by plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Análise experimental de blocos intertravados de concreto com adição de resíduos do processo de recauchutagem de pneus = Analysis of experimental interlocking blocks of concrete with addition of residues of process the tires retreading production

    Directory of Open Access Journals (Sweden)

    Cesar Fabiano Fioriti

    2010-07-01

    Full Text Available Com o aumento da população nos últimos anos, a indústria de modo geral tem se adequado à demanda resultante. A indústria do processo de recauchutagem de pneus gera resíduos que em sua maioria têm sido descartados sem nenhum controle. Este fato contribui para aumentar a poluição ambiental e favorecer a proliferação de vetores nocivos àsaúde. Visando encontrar uma aplicação para esse tipo de resíduo, neste trabalho serão apresentados resultados experimentais de blocos intertravados para pavimentos de concreto, com traços adicionados de resíduos de pneus. Foram confeccionados blocos intertravados em que se determinou, por meio de ensaios laboratoriais, a necessidade de se fixar o traço que desse maior retorno quanto às características analisadas. Verificaram-se quatro tipos de traços de concreto com resíduos de pneus. Procedeu-se aos ensaios de resistência mecânicaà compressão, absorção de água e resistência ao impacto. Pelos resultados preliminares obtidos, verificou-se que são satisfatórios, confirmando-se a possibilidade de aplicação desse tipo de bloco intertravado em ambientes com solicitações baixas, o que traria, além da economia das fontes naturais de agregados, benefícios ecológicos pela reutilização dos resíduos da recauchutagem de pneus.With the population growth in recent years, industry in general has ajusted itself to resulting demand. the industry of tire retreading generates residues that have been discarded without any control. this adds to environmental pollution and promotes the proliferation of vectors harmful to health. aiming to find an application for this type of residues, this study presents experimental results to interlocking concrete block pavements, with addition of residuestires. interlocking blocks were built up and we determined, through laboratory tests, the need to set the mark that provide greater return regarding analyzed characteristics. there are four types of dosage

  9. Soil nutrients losses by wind erosion in a citrus crop at southeast Spain

    Science.gov (United States)

    Segovia, C.; Gómez, J. D.; Gallardo, P.; Lozano, F. J.; Asensio, C.

    2017-06-01

    The purpose of this study was to analyze the influence of wind erosion on the productivity of citric crops over gypsiric Fluvisols in Gador area (Almeria, SE Spain) by blowing air through a wind tunnel. Wind erosion varies considerably depending on time since the last tillage. This is because a physical crust forms after tilling which protects the soil from wind. Crust formation in the study area is strongly favored by dew, which causes them to form in around a week. The repeated measurements ANOVA, as a nonparametric alternative to the ANOVA, using the Geiiser method and the Friedman test shows significant differences ( P ≤ 0.05) in the fractions of very fine sand and coarse silt, which confirmed that very fine sand and coarse silt are the fractions most susceptible to loss from wind. The same statistical analysis for fertility showed smaller differences in organic carbon and K2O content, while N and P2O5 increased. Nutrients lost from wind imply an additional fertilization cost for a crop to be economically feasible. The cost of this restoration of nutrients lost from the soil because of wind erosion was based on experimental data taken in crusted soil and immediately after tilling. Losses in organic matter (O.M.), N, P2O5 and K2O were estimated based on the cost of fertilizers most commonly used in the area.

  10. Nutrient Management in Recirculating Hydroponic Culture

    Science.gov (United States)

    Bugbee, Bruce

    2004-01-01

    There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

  11. Nutrient management strategies on Dutch dairy farms: an empirical analysis

    NARCIS (Netherlands)

    Ondersteijn, C.J.M.

    2002-01-01

    Key Words: MINAS; nitrogen surplus; phosphate surplus; nutrient efficiency; nutrient productivity; financial consequences; strategic management; perceived environmental uncertainty; nutrient management planning; dairy farming; The Netherlands.

    Agricultural nutrients are a

  12. Effects of nutrient omission in Caesalpinia echinata plants

    Directory of Open Access Journals (Sweden)

    Sergio Valiengo Valeri

    2014-03-01

    Full Text Available The objective of this study was to evaluate the growth, the morphological alterations and the mineral composition of brazilwood (Caesalpinia echinata plants caused by mineral nutrients omission in a green house experiment. The experimental units were distributed in the green house according to a completely random design. The treatments, each repeated five times, were the following : check (natural soil, complete (N, P, K, Ca, Mg, S, B, Cu, Mn, and Zn and a complete solution but for the omission of one of the nutrients in parenthesis. Each plot was represented by a plant growing in a 7 dm3 vase filled with Quartzarenic Neosol. The analyzed variables were the following: visual nutritional deficiency symptoms, plant height, stem diameter, shoot dry matter, stem, branches and leaves included, and leaf nutrients level. The omission of nitrogen limited plant growth in height and shoot biomass production. The first visual deficiency symptoms were those due to N omission followed by those caused by P, Ca, Mg, S, Cu, and Mn omissions. Later on the K and B deficiency symptoms became visible. The omission of a nutrient always caused its level in the leaves to be significantly lower than that found when it was not omitted.

  13. Even more Chironomid species for classifying lake nutrient status

    Directory of Open Access Journals (Sweden)

    Les Ruse

    2015-07-01

    Full Text Available The European Union Water Framework Directive (WFD classifies ecological status of a waterbody by the determination of its natural reference state to provide a measure of perturbation by human impacts based on taxonomic composition and abundance of aquatic species. Ruse (2010; 2011 has provided methods of assessing anthropogenic perturbations to lake ecological status, in terms of nutrient enrichment and acidification, by analysing collections of floating pupal exuviae discarded by emerging adult Chironomidae. The previous nutrient assessment method was derived from chironomid and environmental data collected during 178 lake surveys of all WFD types found in Britain. Canonical Correspondence Analysis provided species optima in relation to phosphate and nitrogen concentrations. Species found in less than three surveys were excluded from analysis in case of spurious association with environmental values. Since Ruse (2010 an additional 72 lakes have been surveyed adding 31 more species for use in nutrient status assessment. These additional scoring species are reported here. The practical application of the Chironomid Pupal Exuvial Technique (CPET to classify WFD lake nutrient status is demonstrated using CPET survey data from lakes in Poland.

  14. Quantifying the effects of interacting nutrient cycles on terrestrial biosphere dynamics and their climate feedbacks (QUINCY)

    Science.gov (United States)

    Zaehle, Sönke; Caldararu, Silvia; Eder, Lucia; Engel, Jan; Kern, Melanie; Schrumpf, Marion; Weber, Enrico

    2017-04-01

    Nutrient availability plays a pivotal role in the response of terrestrial ecosystems to increasing atmospheric CO2 and climate change. The first generation of global nutrient-carbon cycle models shows strongly diverging estimates of the nutrient effect, resulting from lacking integration of ecosystem observations and fundamental uncertainties in the representation of governing processes. The two fundamental areas in which advances in modelling are required at i)the effects of nutrient availability on plant photosynthesis and respiration by explicitly taking the energy requirement of nutrient acquisition into account, and ii) the effects of vegetation-soil interactions, namely rhizosphere processes, on plant nutrient availability and soil C turnover. Here we present the methodology and first results of the QUINCY project, which addresses these important issues by an approach encompassing experimentation and model development. In particular, we outline a novel modelling approach to systematically link carbon, nutrient and water flows within the framework of a general land surface model at time-scales of minutes to decades, and illustrate, how (new) experimental data can (better) constrain this novel model.

  15. Responses to mineral nutrient availability and heterogeneity in physiologically integrated sedges from contrasting habitats.

    Science.gov (United States)

    D'Hertefeldt, T; Falkengren-Grerup, U; Jónsdóttir, I S

    2011-05-01

    Clonal plants from poor habitats benefit less from morphologically plastic responses to heterogeneity than plants from more productive sites. In addition, physiological integration has been suggested to either increase or decrease the foraging efficiency of clonal plants. We tested the capacity for biomass production and morphological response in two closely related, rhizomatous species from habitats that differ in resource availability, Carex arenaria (from poor sand dunes) and C. disticha (from nutrient-richer, moister habitats). We expected lower total biomass production and reduced morphological plasticity in C. arenaria, and that both species would produce more ramets in high nutrient patches, either in response to signals transported through physiological integration, or by locally determined responses to nutrient availability. To investigate mineral nutrient heterogeneity, plants were grown in boxes divided into two compartments with homogeneous or heterogeneous supply of high (H) or low (L) nutrient levels, resulting in four treatments, H-H, H-L, L-H and L-L. Both C. arenaria and C. disticha produced similar biomass in high nutrient treatments. C. disticha responded to high nutrients by increased biomass production and branching of the young parts and by altering root:shoot ratio and rhizome lengths, while C. arenaria showed localised responses to high nutrients in terms of local biomass and branch production in high nutrient patches. The results demonstrated that although it has a conservative morphology, C. arenaria responded to nutrient heterogeneity through morphological plasticity. An analysis of costs and benefits of integration on biomass production showed that young ramets of both species benefited significantly from physiological integration, but no corresponding costs were found. This suggests that plants from resource-poor but dynamic habitats like sand dunes respond morphologically to high nutrient patches. The two species responded to nutrient

  16. Transient dynamics of pelagic producer-grazer systems in a gradient of nutrients and mixing depths.

    Science.gov (United States)

    Jäger, Christoph G; Diehl, Sebastian; Matauschek, Christian; Klausmeier, Christopher A; Stibor, Herwig

    2008-05-01

    Phytoplankton-grazer dynamics are often characterized by long transients relative to the length of the growing season. Using a phytoplankton-grazer model parameterized for Daphnia pulex with either flexible or fixed algal carbon:nutrient stoichiometry, we explored how nutrient and light supply (the latter by varying depth of the mixed water column) affect the transient dynamics of the system starting from low densities. The system goes through an initial oscillation across nearly the entire light-nutrient supply space. With flexible (but not with fixed) algal stoichiometry, duration of the initial algal peak, timing and duration of the subsequent grazer peak, and timing of the algal minimum are consistently accelerated by nutrient enrichment but decelerated by light enrichment (decreasing mixing depth) over the range of intermediate to shallow mixing depths. These contrasting effects of nutrient vs. light enrichment are consequences of their opposing influences on food quality (algal nutrient content): algal productivity and food quality are positively related along a nutrient gradient but inversely related along a light gradient. Light enrichment therefore slows down grazer growth relative to algal growth, decelerating oscillatory dynamics; nutrient enrichment has opposite effects. We manipulated nutrient supply and mixing depth in a field enclosure experiment. The experimental results were qualitatively much more consistent with the flexible than with the fixed stoichiometry model. Nutrient enrichment increased Daphnia peak biomass, decreased algal minimum biomass, decreased the seston C:P ratio, and accelerated transient oscillatory dynamics. Light enrichment (decreasing mixing depth) produced the opposite patterns, except that Daphnia peak biomass increased monotonously with light enrichment, too. Thus, while the model predicts the possibility of the "paradox of energy enrichment" (a decrease in grazer biomass with light enrichment) at high light and low

  17. Divergent [{ONNN}Mg–Cl] complexes in highly active and living lactide polymerization† †Electronic supplementary information (ESI) available: Experimental data regarding the synthesis and characterization of the ligands, complexes and PLA polymers. CCDC 1537631–1537632. For ESI and crystallographic data in CIF format or other electronic format see DOI: 10.1039/c7sc01514c Click here for additional data file. Click here for additional data file. Click here for additional data file.

    Science.gov (United States)

    Rosen, Tomer; Goldberg, Israel; Navarra, Wanda

    2017-01-01

    Chloro-magnesium complexes of divergent tetradentate-monoanionic {ONNN}-type ligands which formed as either mononuclear or dinuclear complexes are reported. These complexes catalyze the ring-opening polymerization of lactide with high activity and in a living manner, and enable the synthesis of well-defined stereo-diblock copolymers with M n > 200 kDa, as well as stereo-n-block copolymers (n = tri, tetra) with high molecular weights by sequential monomer addition. Thermal and crystallographic characterizations revealed that even the very high molecular weight PLA copolymers crystallized in a stereocomplex phase, and that their degradation temperature was as high as 354 °C. PMID:28970927

  18. A novel approach to selecting and weighting nutrients for nutrient profiling of foods and diets.

    Science.gov (United States)

    Arsenault, Joanne E; Fulgoni, Victor L; Hersey, James C; Muth, Mary K

    2012-12-01

    Nutrient profiling of foods is the science of ranking or classifying foods based on their nutrient composition. Most profiling systems use similar weighting factors across nutrients due to lack of scientific evidence to assign levels of importance to nutrients. Our aim was to use a statistical approach to determine the nutrients that best explain variation in Healthy Eating Index (HEI) scores and to obtain β-coefficients for the nutrients for use as weighting factors for a nutrient-profiling algorithm. We used a cross-sectional analysis of nutrient intakes and HEI scores. Our subjects included 16,587 individuals from the National Health and Nutrition Examination Survey 2005-2008 who were 2 years of age or older and not pregnant. Our main outcome measure was variation (R(2)) in HEI scores. Linear regression analyses were conducted with HEI scores as the dependent variable and all possible combinations of 16 nutrients of interest as independent variables, with covariates age, sex, and ethnicity. The analyses identified the best 1-nutrient variable model (with the highest R(2)), the best 2-nutrient variable model, and up to the best 16-nutrient variable model. The model with 8 nutrients explained 65% of the variance in HEI scores, similar to the models with 9 to 16 nutrients, but substantially higher than previous algorithms reported in the literature. The model contained five nutrients with positive β-coefficients (ie, protein, fiber, calcium, unsaturated fat, and vitamin C) and three nutrients with negative coefficients (ie, saturated fat, sodium, and added sugar). β-coefficients from the model were used as weighting factors to create an algorithm that generated a weighted nutrient density score representing the overall nutritional quality of a food. The weighted nutrient density score can be easily calculated and is useful for describing the overall nutrient quality of both foods and diets. Copyright © 2012 Academy of Nutrition and Dietetics. Published by

  19. Nutrient needs of performance horses

    Directory of Open Access Journals (Sweden)

    Laurie Lawrence

    2008-07-01

    Full Text Available In 1989, the National Research Council (NRC Subcommittee on Horse Nutrition defined three categories of exercise: light, moderate or intense. In the 6th revised edition of "The Nutrient Requirements of Horses" (NRC, 2007, there are four categories for exercising horses: light exercise, moderate exercise, heavy exercise and very heavy exercise. Light exercise is described as 1 to 3 hours/week of mostly walking and trotting. Many horses kept for recreational riding would be included in the light exercise category. Moderate exercise consists of 3 to 5 hours/week of mostly trotting with some walking, some cantering and possibly some jumping or other type of more difficult activity. Horses used for horse shows, ranch work and frequent recreational riding would fit into the moderate exercise category. Heavy exercise is described as 4 to 5 hours/week of trotting, cantering, galloping and some jumping, cattle work, etc. Horses engaged in three day eventing, polo, endurance racing or other competitive events would be in this category. The very heavy exercise category includes racehorses and a few other horses that compete at the elite level of endurance or three day eventing. The NRC (2007 provides recommendations for nutrient intakes by mature exercising horses and for yearlings and two year olds that are receiving regular exercise. Many of the recommendations are similar to those in the 1989 publication, but others have been increased or decreased. For example, crude protein recommendations for exercising horses are generally lower than in the last edition. However, lysine requirements are relatively similar and the publication suggests that protein quality should be emphasized more than in the past. The 2007 NRC contains more information about the factors that influence the requirements for each nutrient, making it easier for users to develop diets for individual horses.

  20. High nutrient availability reduces the diversity and stability of the equine caecal microbiota

    Directory of Open Access Journals (Sweden)

    Naja C. K. Hansen

    2015-08-01

    Full Text Available Background: It is well known that nutrient availability can alter the gut microbiota composition, while the effect on diversity and temporal stability remains largely unknown. Methods: Here we address the equine caecal microbiota temporal stability, diversity, and functionality in response to diets with different levels of nutrient availability. Hay (low and slower nutrient availability versus a mixture of hay and whole oats (high and more rapid nutrient availability were used as experimental diets. Results: We found major effects on the microbiota despite that the caecal pH was far from sub-clinical acidosis. We found that the low nutrient availability diet was associated with a higher level of both diversity and temporal stability of the caecal microbiota than the high nutrient availability diet. These observations concur with general ecological theories, suggesting a stabilising effect of biological diversity and that high nutrient availability has a destabilising effect through reduced diversity. Conclusion: Nutrient availability does not only change the composition but also the ecology of the caecal microbiota.

  1. Nutrientes minerales en alimentos industrializados

    OpenAIRE

    Hernández F., Eloisa; Facultad de Farmacia y Bioquímica de la Universidad Nacional Mayor de San Marcos, Lima, Perú.; Quispe, Clara; Facultad de Farmacia y Bioquímica de la Universidad Nacional Mayor de San Marcos, Lima, Perú.; Alencastre M., Ana; Facultad de Farmacia y Bioquímica de la Universidad Nacional Mayor de San Marcos, Lima, Perú.

    2014-01-01

    Hasta el momento los alimentos industrializados que se consumen en nuestro medio aún no han sido estudiados por su contenido de nutrientes minerales. Se presenta los contenidos de fósforo, calcio, hierro, sodio, potasio, cobre y magnesio en 33 alimentos de procedencia nacional e importados. El 70% de estos alimentos son preferentemente consumidos por niños. Se ha empleado métodos oficiales de A.O.A.C.: para fósforo el método colorimétrico, los otros minerales mediante Absorción Atómica, Espec...

  2. Harvesting nutrients from source-separated urine using powdered rice straw.

    Science.gov (United States)

    Hashemi, Shervin; Han, Mooyoung

    2017-05-07

    As a principle of resource-oriented sanitation practice, urine should be separated from the source and utilized for other purposes such as producing fertilizer. This is because urine is rich in nutrients; therefore, sending it directly to wastewater treatment plants causes problems in the regular treatment process. The addition of solid additives such as powdered rice straw can help with harvesting nutrients from urine. In this study, the procedure and efficiency of using powdered rice straw for nutrient harvesting were investigated by tracking the reductions in ammonia, phosphate, magnesium, and calcium ions, and the harvested nutrients were identified using crystallography methods. Results show that the ammonia, phosphate, and magnesium ions showed similar reduction trends. However, the reduction process was limited by the magnesium and phosphate availability, which reduced the nutrient harvesting efficiency. The nutrients harvested with the rice straw were identified to be mostly struvite. Balancing the phosphate and magnesium ions with ammonia is recommended to improve the efficiency of nutrient harvesting. The treated powdered rice straw can serve as a good solid fertilizer, while the remaining urine, which includes fewer nutrients, can be utilized for irrigation or sent to wastewater treatment plants.

  3. Compost supplementation with nutrients and microorganisms in composting process.

    Science.gov (United States)

    Sánchez, Óscar J; Ospina, Diego A; Montoya, Sandra

    2017-11-01

    The composting is an aerobic, microorganism-mediated, solid-state fermentation process by which different organic materials are transformed into more stable compounds. The product obtained is the compost, which contributes to the improvement of physical, chemical and microbiological properties of the soil. However, the compost usage in agriculture is constrained because of its long-time action and reduced supply of nutrients to the crops. To enhance the content of nutrients assimilable by the plants in the compost, its supplementation with nutrients and inoculation with microorganisms have been proposed. The objective of this work was to review the state of the art on compost supplementation with nutrients and the role played by the microorganisms involved (or added) in their transformation during the composting process. The phases of composting are briefly compiled and different strategies for supplementation are analyzed. The utilization of nitrogenous materials and addition of microorganisms fixing nitrogen from the atmosphere or oxidizing ammonia into more assimilable for plants nitrogenous forms are analyzed. Several strategies for nitrogen conservation during composting are presented as well. The supplementation with phosphorus and utilization of microorganisms solubilizing phosphorus and potassium are also discussed. Main groups of microorganisms relevant during the composting process are described as well as most important strategies to identify them. In general, the development of this type of nutrient-enriched bio-inputs requires research and development not only in the supplementation of compost itself, but also in the isolation and identification of microorganisms and genes allowing the degradation and conversion of nitrogenous substances and materials containing potassium and phosphorus present in the feedstocks undergoing the composting process. In this sense, most important research trends and strategies to increase nutrient content in the compost

  4. Understanding Stoichiometric Controls in Nutrient Processing Along the River Continuum

    Science.gov (United States)

    Garayburu-Caruso, V. A.; Gonzalez-Pinzon, R.; Van Horn, D. J.; Covino, T. P.

    2016-12-01

    Eutrophication is the second most common cause of water impairment across the U.S. Nutrient retention in streams is controlled by physical and biochemical processes, including biomass availability and stoichiometric limitations. Decoupling the interactions between hydrology, nutrient supply and biogeochemical processes remains challenging for the scientific community due to lack of mechanistic understanding. Consequently, more knowledge regarding optimal controls for nutrient retention is needed to implement better management and restoration practices. We conducted column experiments to investigate how stoichiometric limitations influence nutrient spiraling in shallow sediment-water interactions along representative sites of the Jemez River-Rio Grande continuum (which spans eight stream orders), in New Mexico, USA. In each stream order we incubated six columns packed with different sediments (i.e., Silica Cone Density Sand ASTM D 1556 (0.075-2.00 mm), gravel (>2mm) and native sediments) from each site for three months. We performed two laboratory tracer experiments using columns of each substrate under identical flow conditions. In the first experiment we added a short-term pulse of reactive and conservative tracers (i.e. NaNO3 and NaBr). In the second experiment we added a short-term pulse of NaBr and nutrients following Redfield's ratio (106C:16N:1P). We estimated uptake kinetics using the Tracer Additions for Spiraling Curve Characterization (TASCC) method and evaluated how ideal stoichiometric conditions controlled efficient nutrient retention along fluvial networks. Our results suggest that biological uptake of nitrate is limited by nitrogen in headwater streams and by phosphorus and carbon in larger stream orders.

  5. Computed Tomography Findings of Mandibular Nutrient Canals.

    Science.gov (United States)

    Kawashima, Yusuke; Sekiya, Kotaro; Sasaki, Yusuke; Tsukioka, Tsuneyuki; Muramatsu, Teruaki; Kaneda, Takashi

    2015-08-01

    The purpose of this study was to assess computed tomography (CT) findings of mandibular nutrient canals using CT images. We retrospectively analyzed the mandibular CT images of 194 consecutive patients. For image analysis such as canal prevalence, location, number, size, shape, and the CT value of nutrient foramina were determined using CT axial images of 0.5 and 3 mm slice thickness. We revealed that the nutrient canals were seen 94.3% in the mandible, mostly seen in the anterior region. By location, nutrient canals were particularly seen between the central and lateral incisors. The mean number of nutrient canals was 2.7. The mean diameter of the nutrient foramen between the central and lateral incisors was 1.0 mm. In about 80% of the cases, foramina between the central and lateral incisors were ovoid. The mean CT value for the nutrient foramina between the central and lateral incisors was 411 HU. Mandibular nutrient canals were ovoid shape, and the mean CT value was 411 HU. By preoperative knowledge of the position and anatomy of the mandibular nutrient canals, complications such as injury to the nutrient canals can be avoided.

  6. Organic soil production from urban soil, spent mushroom substrate, and other additives

    Science.gov (United States)

    Pham, Nhung Thi Ha

    2017-09-01

    In recent years, spent mushroom substrate (SMS) is becoming the huge problem in environmental pollution issues from mushroom production. However, SMS is also a nutrient-rich ogranic material with available nutrients and high porosity. Therefore, the value of products made from SMS should be exploited to take full advantage of agricultural by-product, support organic agriculture development without environmental pollution. The research has built 5 experimental formulas (4 mixed formulas and 1 control formulas with only urban soil). The analysis results of soil samples from mixed formulas and the control formula witness a significant increase in moisture and OM of mixed formulas (moisture from 36-42%, OM from 5.5-6.9%) after 20 treatment days, and N-P-K contents are also improved remarkably. 60 days later, soil nutrients in mixed formulas continue to rise, with highest OM (8.679%) at CT1; N (0.154%) at CT4; K2O (0,698%) and P2O5 (0,172%) at CT3, in addition, heavy metal contents in all formulas are under standard limit. Synthetic assessment of all norms indicates that the best organic soil product comes from CT3. The pak choi planting experiments are performed show that the growth of plants cultivated on organic soil products made from mixed formulas are much better than plants are grown on initially soil, and they also have no pestilent insect. Specially, pak choi planted on organic soil from CT3 have sharp developing with excellent tolerance ability, quantity and area of leaves are high. Thus, CT3 is the most suitable formula to increase soil nutrients, to solve spent mushroom subtrate streament problems after harvest, and for sustainable agricultural development.

  7. Can algal biotechnology bring effective solution for closing the phosphorus cycle? Use of algae for nutrient removal: Review of past trends and future perspectives in the context of nutrient recovery

    Directory of Open Access Journals (Sweden)

    Kateřina Sukačová

    2017-06-01

    Full Text Available Eutrophication of water by nutrient pollution is a global environmental issue. Biological methods for removing nutrients are environmentally friendly and sustainable. Therefore, this article summarizes main trends in the use of algae for removing nutrients from wastewater using both suspended and attached algal-based systems. A wide variety of algal species and experimental approaches has been tested to date. Researchers report that algae are able to effectively remove a variety of pollutants and nutrients. This review also discusses the potential of algal-based technology for nutrient, especially phosphorus, recovery. Despite the fact that effective nutrient removal has been demonstrated, there are still many challenges to be overcome in the development of succesfull technologies.

  8. Solar H2 evolution in water with modified diketopyrrolopyrrole dyes immobilised on molecular Co and Ni catalyst–TiO2 hybrids† †Electronic supplementary information (ESI) available: Experimental details, synthetic procedures, additional tables and figures. See DOI: 10.1039/c6sc05219c Click here for additional data file.

    Science.gov (United States)

    Warnan, Julien; Willkomm, Janina; Ng, Jamues N.; Godin, Robert; Prantl, Sebastian; Durrant, James R.

    2017-01-01

    A series of diketopyrrolopyrrole (DPP) dyes with a terminal phosphonic acid group for attachment to metal oxide surfaces were synthesised and the effect of side chain modification on their properties investigated. The organic photosensitisers feature strong visible light absorption (λ = 400 to 575 nm) and electrochemical and fluorescence studies revealed that the excited state of all dyes provides sufficient driving force for electron injection into the TiO2 conduction band. The performance of the DPP chromophores attached to TiO2 nanoparticles for photocatalytic H2 evolution with co-immobilised molecular Co and Ni catalysts was subsequently studied, resulting in solar fuel generation with a dye-sensitised semiconductor nanoparticle system suspended in water without precious metal components. The performance of the DPP dyes in photocatalysis did not only depend on electronic parameters, but also on properties of the side chain such as polarity, steric hinderance and hydrophobicity as well as the specific experimental conditions and the nature of the sacrificial electron donor. In an aqueous pH 4.5 ascorbic acid solution with a phosphonated DuBois-type Ni catalyst, a DPP-based turnover number (TONDPP) of up to 205 was obtained during UV-free simulated solar light irradiation (100 mW cm–2, AM 1.5G, λ > 420 nm) after 1 day. DPP-sensitised TiO2 nanoparticles were also successfully used in combination with a hydrogenase or platinum instead of the synthetic H2 evolution catalysts and the platinum-based system achieved a TONDPP of up to 2660, which significantly outperforms an analogous system using a phosphonated Ru tris(bipyridine) dye (TONRu = 431). Finally, transient absorption spectroscopy was performed to study interfacial recombination and dye regeneration kinetics revealing that the different performances of the DPP dyes are most likely dictated by the different regeneration efficiencies of the oxidised chromophores. PMID:28451376

  9. Hierarchical tailoring of strut architecture to control permeability of additive manufactured titanium implants.

    Science.gov (United States)

    Zhang, Z; Jones, D; Yue, S; Lee, P D; Jones, J R; Sutcliffe, C J; Jones, E

    2013-10-01

    Porous titanium implants are a common choice for bone augmentation. Implants for spinal fusion and repair of non-union fractures must encourage blood flow after implantation so that there is sufficient cell migration, nutrient and growth factor transport to stimulate bone ingrowth. Additive manufacturing techniques allow a large number of pore network designs. This study investigates how the design factors offered by selective laser melting technique can be used to alter the implant architecture on multiple length scales to control and even tailor the flow. Permeability is a convenient parameter that characterises flow, correlating to structure openness (interconnectivity and pore window size), tortuosity and hence flow shear rates. Using experimentally validated computational simulations, we demonstrate how additive manufacturing can be used to tailor implant properties by controlling surface roughness at a microstructual level (microns), and by altering the strut ordering and density at a mesoscopic level (millimetre). Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Pretreatment of brewery effluent to cultivate Spirulina sp. for nutrients removal and biomass production.

    Science.gov (United States)

    Lu, Qian; Liu, Hui; Liu, Wen; Zhong, Yuming; Ming, Caibing; Qian, Wei; Wang, Qin; Liu, Jianliang

    2017-10-01

    Due to the low concentration of nitrate and high contents of organics, brewery effluent was not suitable for the cultivation of Spirulina sp. This work changed the nutrient profile of brewery effluent effectively by dilution, addition of nitrate, and anaerobic digestion. The result showed that the optimum dilution rate and NaNO3 addition for brewery effluent were 20% and 0.5 g/L, respectively. Spirulina sp. grown in pretreated brewery effluent produced 1.562 mg/L biomass and reduced concentrations of nutrients to reach the permissible dischargeable limits. In addition, Spirulina sp. grown in pretreated brewery effluent had much higher protein content and oil content. So the appropriate treatment converted brewery effluent into a nutrient balanced medium for algae cultivation and alleviated the potential environmental problems. Pretreatment procedure developed in this work is an effective way to realize the sustainable utilization of brewery effluent and produce algal biomass with valuable nutrients.

  11. Managing urban nutrient biogeochemistry for sustainable urbanization.

    Science.gov (United States)

    Lin, Tao; Gibson, Valerie; Cui, Shenghui; Yu, Chang-Ping; Chen, Shaohua; Ye, Zhilong; Zhu, Yong-Guan

    2014-09-01

    Urban ecosystems are unique in the sense that human activities are the major drivers of biogeochemical processes. Along with the demographic movement into cities, nutrients flow towards the urban zone (nutrient urbanization), causing the degradation of environmental quality and ecosystem health. In this paper, we summarize the characteristics of nutrient cycling within the urban ecosystem compared to natural ecosystems. The dynamic process of nutrient urbanization is then explored taking Xiamen city, China, as an example to examine the influence of rapid urbanization on food sourced nitrogen and phosphorus metabolism. Subsequently, the concept of a nutrient footprint and calculation method is introduced from a lifecycle perspective. Finally, we propose three system approaches to mend the broken biogeochemical cycling. Our study will contribute to a holistic solution which achieves synergies between environmental quality and food security, by integrating technologies for nutrient recovery and waste reduction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Maize nutrient uptake affected by genotype and fertilization

    Directory of Open Access Journals (Sweden)

    Đalović Ivica

    2015-01-01

    Full Text Available The content of nutrients in maize are commonly related with fertilization and soil quality and rarely explained with the individual hybrid properties. Therefore, the aim of this study is to access a long term fertilization system on ear leaf of Mg, Fe, Mn and Cu content in six maize hybrids(NS 3014, NS 4015, NS 5043, NS 6010, NS 6030 and NS 7020. Samples were collected from a long-term experiment at the Rimski Šančevi experimental field of the Institute of Field and Vegetable Crops in Novi Sad. The study included maize monoculture and 2-year rotations with the application of NPK and manure. Results showed that ear Mg content was influenced with the treatments, hybrid and their interaction and ranged from 1.77-2.69 g kg-1. Iron variability was significantly affected with the treatments and interaction (hybrid x treatments in range from 103.2 to151.9g kg-1. The ear manganese content (41.1-63.6g kg-1 derived from treatments and hybrid effect and Cu (12.3-23.6 g kg-1 was significantly influenced with treatments. Across all treatments, in average, NS6030 had higher values of nutrient and NS3014 was lower in ear nutrient content. This indicates that vegetation length could favor nutrient accumulation. Obtained results suggested that even on fairly productive soil such as Chernozem hybrid selection and the balanced fertilization is crucial for managing the maize nutrient content. [Projekat Ministarsva nauke Republike Srbije, br. TR031073

  13. Biomass and nutrient cycling by winter cover crops

    Directory of Open Access Journals (Sweden)

    Jana Koefender

    Full Text Available ABSTRACT Cover crops are of fundamental importance for the sustainability of the no-tillage system, to ensure soil coverage and to provide benefits for the subsequent crop. The objective of this study was to evaluate the production of biomass and the content and accumulation of nutrients by winter cover crops. The experimental design used in the experiment was a randomized complete block with four replications and six treatments: oilseed radish, vetch, black oats, vetch + black oats, vetch + oilseed radish and fallow. Black oat, oilseed radish in single cultivation and black oat + vetch and vetch + oilseed radish intercroppings showed higher dry matter production. Vetch + oilseed radish intercropping demonstrates higher performance regarding cycling of nutrients, with higher accumulations of N, P, K, Ca, Mg, S, Cu, Zn, Fe, Na and B.

  14. The fluid mechanics of nutrient transport within biofilms

    Science.gov (United States)

    Brenner, Michael; Seminara, Agnese; Sinha, Naveen; Wilking, James; Angelini, Tommy; Kolter, Roberto; Weitz, David

    2011-11-01

    Bacterial biofilms are interface-associated colonies of bacteria embedded in an extracellular matrix that is composed primarily of polymers and proteins. During the growth of a biofilm, nutrient is taken up by the surface of the biofilm, and contained by cells in the bulk. A critical problem is that above a critical size there is necessarily a growth bottleneck, in which the biofilm cannot take up enough nutrients to feed all of the cells within it. We discuss, through theory and experiments, several strategies that are employed by biofilms of Bacillus subtilus to avoid this growth bottleneck. These include clever use and control of osmotic pressure (through the expression of polymeric extracellular matrix); the excretion of surfactants and the use of associated marangoni stresses; and the distribution of flagella (used as mixers) within the bulk of the biofilm. Some speculations about other potential mechanisms (for which there is no current experimental support) will also be presented.

  15. Methane productivity and nutrient recovery from manure

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, H.B.

    2003-07-01

    The efficient recovery of energy and improvements in the handling of nutrients from manure have attracted increased research focus during recent decades. Anaerobic digestion is a key process in any strategy for the recovery of energy, while slurry separation is an important component in an improved nutrient-handling strategy. This thesis is divided into two parts: the first deals mainly with nutrient recovery strategies and the second examines biological degradation processes, including controlled anaerobic digestion. (au)

  16. Nutrient pharmacotherapy for gut mucosal diseases.

    Science.gov (United States)

    Rothstein, R D; Rombeau, J L

    1998-06-01

    The use of nutrients for pharmacotherapy is a recent advance in the treatment of gastrointestinal disorders or alterations of gut function and structure. Nutrients may have a direct effect on the gut, or may enhance the response to medications. Alternatively, pharmacologic agents may improve the absorption of nutrients. Potentially, pharmacotherapy may be an adjunct to the traditional approach used in the treatment of compromised patients.

  17. Diapycnal Fluxes of Nutrients in an Oligotrophic Oceanic Regime: The South China Sea

    Science.gov (United States)

    Du, Chuanjun; Liu, Zhiyu; Kao, Shuh-Ji; Dai, Minhan

    2017-11-01

    Nutrients from depth have been hypothesized as a primary source of new nutrients that sustain new productivity in oligotrophic oceans; however, the flux is challenging to quantify. Here we show for a first time in the oligotrophic South China Sea an extremely low diapycnal dissolved inorganic nitrogen (DIN) flux as 1.8 × 10-4 mmol m-2 d-1 in the nutrient-depleted layer (NDL) above the nutricline, where other nutrient supplies sustain the new production. Here higher phosphate and silicate fluxes relative to DIN than Redfield stoichiometry further indicate N-limited biological productivity and additional removal of DIN by diatoms. Below the NDL across the nutricline to the base of euphotic zone, termed as nutrient replete layer, the DIN flux is three orders of magnitude larger and sufficient in supporting the export production therein. Here higher DIC flux relative to DIN than Redfield stoichiometry further infers DIC excess in the upper ocean.

  18. Stream Bed Structure as a Determinat for Nutrient Dynamics: Evidence of recent Resoration Efforts in the urban Stream Wienfluss, Vienna (Austria)

    Science.gov (United States)

    Battin, T.; Glaser, S.; Görnet, B.; Hager, U.; Hein, T.; Weigelhofer, G.

    2003-04-01

    A large scale restoration program is being conducted at the urban stream Wienfluss (WF) in order to reconnect the main channel with the wetlands of the flood control reservoir (FCR) at the city limits of Vienna. The aim is to increase the WF´s ecological integrity and to establish an urban seminatural fluvial landscape element. The restoration measures at reach scale are expected to enhance transformation and degradation of material and energy within the stream ecosystem and to increase the ecosystem functionality by natural self purification processes. The phosphate retention capacity of the FCR is 3,90 ± 1,58 g m-2, approximately 13 % of the riverine input, as was shown by nutrient mass balance calculations. 75 % of of the WF phosphate pool are adsorbed to the sediment, primarily organic bound. An experimental approach using in vitro flow bioreactors demonstrated that the potential ammonia retention of the microbial community is 25 ± 6,5 (g N L-1 (90 ± 3,5%). Stream bed structure within the ecosystem ranges from high habitat heterogeneity in the FCR to monotonous habitat conditions at the concealed reach of the main channel. The degree of habitat heterogeneity is defined through sinuosity length and sediment composition governing vertical and lateral hydrological connectivity. We assume that at base flow stream bed structure acts as the controlling factor for nutrient retention and organic matter dynamics. Thus nutrient uptake length should increase with decreasing habitat heterogeneity. In the present experimental nutrient addition study we compare the nutrient retention efficiency of three reaches with different stream bed structures. Sediments range from natural sand to cobble in the FCR, over rip-rap to fine sediment aggregations at the seminatural restructurated section of the main channel, to the concealed reach of the WF. Ammonia and phosphate are added via constant and slug nutrient additions. Basic uptake parameters as uptake rate, uptake rate

  19. Ultrastructural biomarkers in symbiotic algae reflect the availability of dissolved inorganic nutrients and particulate food to the reef coral holobiont

    Directory of Open Access Journals (Sweden)

    Sabrina eRosset

    2015-11-01

    Full Text Available Reef building corals associated with symbiotic algae (zooxanthellae can access environmental nutrients from different sources, most significantly via the uptake of dissolved inorganic nutrients by the algal symbiont and heterotrophic feeding of the coral host. Climate change is expected to alter the nutrient environment in coral reefs with the potential to benefit or disturb coral reef resilience. At present, the relative importance of the two major nutrient sources is not well understood, making predictions of the responses of corals to changes in their nutrient environment difficult. Therefore, we have examined the long-term effects of the availability of different concentrations of dissolved inorganic nutrients and of nutrients in particulate organic form on the model coral Euphyllia paradivisa. Coral and algal biomass showed a significantly stronger increase in response to elevated levels of dissolved inorganic nutrients as compared to the supply with particulate food. Also, changes in the zooxanthellae ultrastructure, determined by transmission electron microscopy (TEM, were mostly driven by the availability of dissolved inorganic nutrients under the present experimental conditions. The larger size of symbiont cells, their increased accumulation of lipid bodies, a higher number of starch granules and the fragmentation of their accumulation body could be established as reliable biomarkers of low availability of dissolved inorganic nutrients to the coral holobiont.

  20. Interactive effects of vertical mixing, nutrients and ultraviolet radiation: in situ photosynthetic responses of phytoplankton from high mountain lakes in Southern Europe

    Science.gov (United States)

    Helbling, E. W.; Carrillo, P.; Medina-Sánchez, J. M.; Durán, C.; Herrera, G.; Villar-Argaiz, M.; Villafañe, V. E.

    2013-02-01

    Global change, together with human activities, has resulted in increasing amounts of organic material (including nutrients) that water bodies receive. This input further attenuates the penetration of solar radiation, leading to the view that opaque lakes are more "protected" from solar ultraviolet radiation (UVR) than clear ones. Vertical mixing, however, complicates this view as cells are exposed to fluctuating radiation regimes, for which the effects have, in general, been neglected. Furthermore, the combined impacts of mixing, together with those of UVR and nutrient inputs are virtually unknown. In this study, we carried out complex in situ experiments in three high mountain lakes of Spain (Lake Enol in the National Park Picos de Europa, Asturias, and lakes Las Yeguas and La Caldera in the National Park Sierra Nevada, Granada), used as model ecosystems to evaluate the joint impact of these climate change variables. The main goal of this study was to address the question of how short-term pulses of nutrient inputs, together with vertical mixing and increased UVR fluxes modify the photosynthetic responses of phytoplankton. The experimentation consisted in all possible combinations of the following treatments: (a) solar radiation: UVR + PAR (280-700 nm) versus PAR (photosynthetically active radiation) alone (400-700 nm); (b) nutrient addition (phosphorus (P) and nitrogen (N)): ambient versus addition (P to reach to a final concentration of 30 μg P L-1, and N to reach N:P molar ratio of 31); and (c) mixing: mixed (one rotation from surface to 3 m depth (speed of 1 m 4 min-1, total of 10 cycles)) versus static. Our findings suggest that under ambient nutrient conditions there is a synergistic effect between vertical mixing and UVR, increasing phytoplankton photosynthetic inhibition and excretion of organic carbon (EOC) from opaque lakes as compared to algae that received constant mean irradiance within the epilimnion. The opposite occurs in clear lakes where

  1. Interactive effects of vertical mixing, nutrients and ultraviolet radiation: in situ photosynthetic responses of phytoplankton from high mountain lakes in Southern Europe

    Directory of Open Access Journals (Sweden)

    E. W. Helbling

    2013-02-01

    Full Text Available Global change, together with human activities, has resulted in increasing amounts of organic material (including nutrients that water bodies receive. This input further attenuates the penetration of solar radiation, leading to the view that opaque lakes are more "protected" from solar ultraviolet radiation (UVR than clear ones. Vertical mixing, however, complicates this view as cells are exposed to fluctuating radiation regimes, for which the effects have, in general, been neglected. Furthermore, the combined impacts of mixing, together with those of UVR and nutrient inputs are virtually unknown. In this study, we carried out complex in situ experiments in three high mountain lakes of Spain (Lake Enol in the National Park Picos de Europa, Asturias, and lakes Las Yeguas and La Caldera in the National Park Sierra Nevada, Granada, used as model ecosystems to evaluate the joint impact of these climate change variables. The main goal of this study was to address the question of how short-term pulses of nutrient inputs, together with vertical mixing and increased UVR fluxes modify the photosynthetic responses of phytoplankton. The experimentation consisted in all possible combinations of the following treatments: (a solar radiation: UVR + PAR (280–700 nm versus PAR (photosynthetically active radiation alone (400–700 nm; (b nutrient addition (phosphorus (P and nitrogen (N: ambient versus addition (P to reach to a final concentration of 30 μg P L−1, and N to reach N:P molar ratio of 31; and (c mixing: mixed (one rotation from surface to 3 m depth (speed of 1 m 4 min−1, total of 10 cycles versus static. Our findings suggest that under ambient nutrient conditions there is a synergistic effect between vertical mixing and UVR, increasing phytoplankton photosynthetic inhibition and excretion of organic carbon (EOC from opaque lakes as compared to algae that received constant mean irradiance within the epilimnion. The

  2. Energy and nutrient density of foods in relation to their carbon footprint.

    Science.gov (United States)

    Drewnowski, Adam; Rehm, Colin D; Martin, Agnes; Verger, Eric O; Voinnesson, Marc; Imbert, Philippe

    2015-01-01

    A carbon footprint is the sum of greenhouse gas emissions (GHGEs) associated with food production, processing, transporting, and retailing. We examined the relation between the energy and nutrient content of foods and associated GHGEs as expressed as g CO2 equivalents. GHGE values, which were calculated and provided by a French supermarket chain, were merged with the Composition Nutritionnelle des Aliments (French food-composition table) nutrient-composition data for 483 foods and beverages from the French Agency for Food, Environmental and Occupational Health and Safety. Foods were aggregated into 34 food categories and 5 major food groups as follows: meat and meat products, milk and dairy products, frozen and processed fruit and vegetables, grains, and sweets. Energy density was expressed as kcal/100 g. Nutrient density was determined by using 2 alternative nutrient-density scores, each based on the sum of the percentage of daily values for 6 or 15 nutrients, respectively. The energy and nutrient densities of foods were linked to log-transformed GHGE values expressed per 100 g or 100 kcal. Grains and sweets had lowest GHGEs (per 100 g and 100 kcal) but had high energy density and a low nutrient content. The more-nutrient-dense animal products, including meat and dairy, had higher GHGE values per 100 g but much lower values per 100 kcal. In general, a higher nutrient density of foods was associated with higher GHGEs per 100 kcal, although the slopes of fitted lines varied for meat and dairy compared with fats and sweets. Considerations of the environmental impact of foods need to be linked to concerns about nutrient density and health. The point at which the higher carbon footprint of some nutrient-dense foods is offset by their higher nutritional value is a priority area for additional research. © 2015 American Society for Nutrition.

  3. Nutrient Sensing: Another Chemosensitivity of the Olfactory System

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    A-Karyn Julliard

    2017-07-01

    Full Text Available Olfaction is a major sensory modality involved in real time perception of the chemical composition of the external environment. Olfaction favors anticipation and rapid adaptation of behavioral responses necessary for animal survival. Furthermore, recent studies have demonstrated that there is a direct action of metabolic peptides on the olfactory network. Orexigenic peptides such as ghrelin and orexin increase olfactory sensitivity, which in turn, is decreased by anorexigenic hormones such as insulin and leptin. In addition to peptides, nutrients can play a key role on neuronal activity. Very little is known about nutrient sensing in olfactory areas. Nutrients, such as carbohydrates, amino acids, and lipids, could play a key role in modulating olfactory sensitivity to adjust feeding behavior according to metabolic need. Here we summarize recent findings on nutrient-sensing neurons in olfactory areas and delineate the limits of our knowledge on this topic. The present review opens new lines of investigations on the relationship between olfaction and food intake, which could contribute to determining the etiology of metabolic disorders.

  4. Properties of plant nutrient: Comparison of two nutrient recovery techniques using liquid fraction of digestate from anaerobic digester treating pig manure.

    Science.gov (United States)

    Li, Xin; Guo, Jianbin; Dong, Renjie; Ahring, Birgitte K; Zhang, Wanqin

    2016-02-15

    Anaerobic digestate has valuable potential as organic fertilizer or soil amendment, given that it typically contains high amounts of plant nutrients, such as nitrogen, phosphate and plant hormones. In this study, ammonia stripping and vacuum evaporation were tested to compare their technical feasibilities and their effects on plant nutrient properties in the liquid fraction of digestate. Results of the batch experiments showed that the nutrient characteristics of liquid digestate, including total ammonia nitrogen (TAN), soluble P, gibberellic acid (GA), indoleacetic acid (IAA) and abscisic acid (ABA), were strongly dependent on the initial pH in both ammonia stripping and vacuum evaporation processes. A low plant nutrient concentration (TAN 137 mg · L(-1), soluble P 1.5 mg · L(-1), GA3/ABA 0.04) in the liquid digestate was achieved in the ammonia stripping process with Ca(OH)2 addition of 12 g · L(-1), whereas a high nutrient concentration (TAN 2998 mg · L(-1), soluble P 178.3 mg · L(-1), IAA 60.9 mg · L(-1) and GA3/ABA 0.4) was achieved in vacuum evaporation at a pH level of 6. According to the results, both ammonia stripping and vacuum evaporation can be used as an alternative of nutrient recovery techniques, which should be chosen based on the potential different applications of liquid digestate (e.g., soaking seed, increasing plant tolerance, and nutrients transportation). Copyright © 2015 Elsevier B.V. All rights reserved.

  5. NONRUMINANT NUTRITION SYMPOSIUM: Nutrient and non-nutrient sensing and signaling in the gastrointestinal tract1

    National Research Council Canada - National Science Library

    J S Radcliffe

    2011-01-01

    .... Here, Radcliffe features a symposium held on Jul 15, 2010 at the annual meeting of the American Society of Animal Science highlighting recent findings regarding "Nutrient and Non-nutrient Sensing...

  6. Fast detection of nutrient limitation in macroalgae and seagrass with nutrient-induced fluorescence.

    NARCIS (Netherlands)

    den Haan, J.; Huisman, J.; Dekker, F.; ten Brinke, J.L.; Ford, A.K.; van Ooijen, J.; van Duyl, F.C.; Vermeij, M.J.A.; Visser, P.M.

    2013-01-01

    Background Rapid determination of which nutrients limit the primary production of macroalgae and seagrasses is vital for understanding the impacts of eutrophication on marine and freshwater ecosystems. However, current methods to assess nutrient limitation are often cumbersome and time consuming.

  7. Fast Detection of Nutrient Limitation in Macroalgae and Seagrass with Nutrient-Induced Fluorescence

    NARCIS (Netherlands)

    den Haan, J.; Huisman, J.; Dekker, F.; ten Brinke, J.L.; Ford, A.K.; van Ooijen, J.; van Duyl, F.C.; Vermeij, M.J.A.; Visser, P.M.

    2013-01-01

    Background: Rapid determination of which nutrients limit the primary production of macroalgae and seagrasses is vital for understanding the impacts of eutrophication on marine and freshwater ecosystems. However, current methods to assess nutrient limitation are often cumbersome and time consuming.

  8. Precipitation controls on nutrient budgets in subtropical and tropical forests and the implications under changing climate

    Science.gov (United States)

    Chang, Chung-Te; Wang, Lih-Jih; Huang, Chuan, Jr.; Liu, Chiung-Pin; Wang, Chiao-Ping; Lin, Neng-Huei; Wang, Lixin; Lin, Teng-Chiu

    2017-05-01

    Biological, geological and hydrological drivers collectively control forest biogeochemical cycling. However, based on a close examination of recent literature, we argue that the role of hydrological control particularly precipitation on nutrient budgets is significantly underestimated in subtropical and tropical forests, hindering our predictions of future forest nutrient status under a changing climate in these systems. To test this hypothesis, we analyzed two decades of monthly nutrient input and output data in precipitation and streamwater from a subtropical forested watershed in Taiwan, one of the few sites that has long-term nutrient input-output data in the tropics and subtropics. The results showed that monthly input and output of all ions and budgets (output - input) of most ions were positively correlated with precipitation quantity and there was a surprisingly greater net ion export during the wet growing season, indicating strong precipitation control on the nutrient budget. The strong precipitation control is also supported by the divergence of acidic precipitation and near neutral acidity of streamwater, with the former being independent from precipitation quantity but the latter being positively related to precipitation quantity. An additional synthesis of annual precipitation quantity and nutrient budgets of 32 forests across the globe showed a strong correlation between precipitation quantity and nutrient output-input budget, indicating that strong precipitation control is ubiquitous at the global scale and is particularly important in the humid tropical and subtropical forests. Our results imply that climate change could directly affect ecosystem nutrient cycling in the tropics through changes in precipitation pattern and amount.

  9. Will nutrient and light limitation prevent eutrophication in an anthropogenically-impacted coastal lagoon?

    Science.gov (United States)

    Domingues, Rita B.; Guerra, Cátia C.; Barbosa, Ana B.; Galvão, Helena M.

    2017-06-01

    The Ria Formosa coastal lagoon (southern Portugal) is a highly productive and valuable temperate ecosystem, subjected to strong anthropogenic impacts and highly vulnerable to climate change. The main goal of this work is to understand ecosystem susceptibility to eutrophication, by evaluating the isolated and combined effects of nutrient (N, P and Si) and light enrichments on phytoplankton growth and community composition during autumn, winter and spring. Microcosms of natural phytoplankton collected in the lagoon were subjected to different nutrient and light treatments and incubated in situ for 48 h. Nutrient consumption, and phytoplankton growth and community structure were evaluated using spectrophotometric methods, and inverted and epifluorescence microscopy. Diatoms were the only group potentially limited by nitrogen, and only during spring. Increased nutrient consumptions were observed for all nutrient additions in all seasons, not associated with phytoplankton growth, suggesting that luxury consumption was used to build up intracellular nutrient pools. Responses to light enrichment were inconsistent among phytoplankton groups, probably due to a high taxonomic seasonal variability. Positive responses to light enrichment were mostly observed during winter. Negative synergistic interactions between nutrients and light were also observed. We conclude that eutrophication is currently not a problem in the Ria Formosa coastal lagoon, but future nutrient enrichments may lead to accelerated growth of specific functional groups and species, if light is not limiting.

  10. Reducing Runoff Loss of Applied Nutrients in Oil Palm Cultivation Using Controlled-Release Fertilizers

    Directory of Open Access Journals (Sweden)

    A. Bah

    2014-01-01

    Full Text Available Controlled-release fertilizers are expected to minimize nutrient loss from crop fields due to their potential to supply plant-available nutrients in synchrony with crop requirements. The evaluation of the efficiency of these fertilizers in tropical oil palm agroecological conditions is not yet fully explored. In this study, a one-year field trial was conducted to determine the impact of fertilization with water soluble conventional mixture and controlled-release fertilizers on runoff loss of nutrients from an immature oil palm field. Soil and nutrient loss were monitored for one year in 2012/2013 under erosion plots of 16 m2 on 10% slope gradient. Mean sediments concentration in runoff amounted to about 6.41 t ha−1. Conventional mixture fertilizer posed the greatest risk of nutrient loss in runoff following fertilization due to elevated nitrogen (6.97%, potassium (13.37%, and magnesium (14.76% as percentage of applied nutrients. In contrast, this risk decreased with the application of controlled-release fertilizers, representing 0.75–2.44% N, 3.55–5.09% K, and 4.35–5.43% Mg loss. Meanwhile, nutrient loss via eroded sediments was minimal compared with loss through runoff. This research demonstrates that the addition of controlled-release fertilizers reduced the runoff risks of nutrient loss possibly due to their slow-release properties.

  11. Bagaço de mandioca na ensilagem do capim-elefante: qualidade das silagens e digestibilidade dos nutrientes Cassava bagasse in elephant grass ensilage: quality of the silage and digestibility of the nutrients

    Directory of Open Access Journals (Sweden)

    F.F. Silva

    2007-06-01

    silage with four different levels of cassava bagasse plus balanced concentrate, with four repetitions per treatment. Silages quality, diet nutrients intake and nutrients digestibility of the silages and total diets were evaluated. Cassava bagasse increased the dry matter (DM content, of the silages preserving them with a pH varying from 3.85 to 4.07 and N-NH3/NT ratio from 6.2 to 7.85. Daily dry matter and crude protein (CP mean intakes did not differ among the treatments (P>0.05. Neutral detergent fiber (NDF and acid detergent fiber (ADF mean intakes showed a decreasing linear behavior (P0.05 for DM (DMD, NDF (NDFD and ADF digestibility (ADFD. The total digestible nutrients (TDN of the silages were similar in all the treatments. The CP (CPD, ether extract (EED and non-fiber carbohydrates digestibility (NFCD of the silages decreased linearly (P0.05 in DMD, CPD, NDFD, ADFD, EED, NFCD and TDN among the experimental diets. The 5% cassava bagasse addition to its elephant grass silage was satisfactory to preservation resulting in good digestibility of the elephant grass silage.

  12. Resposta das algas perifíticas às alterações de temperatura e ao enriquecimento artificial de nutrientes em curto período de tempo - DOI: 10.4025/actascibiolsci.v31i3.1627 Periphytic algae response to temperature changes and artificial nutrient enrichment - DOI: 10.4025/actascibiolsci.v31i3.1627

    Directory of Open Access Journals (Sweden)

    Liliana Rodrigues

    2009-07-01

    Full Text Available O estudo visou avaliar, em um experimento de mesocosmos, a influência da temperatura e de concentrações de nutrientes na abundância das algas perifíticas (exceto Bacillariophyceae na planície de inundação do alto rio Paraná. O delineamento experimental constituiu-se de cinco tratamentos: controle (C e adição de nutrientes (P+, N+ e NP+ a 25°C, e frio (F com diminuição da temperatura a 15°C e sem adição de nutrientes. Lâminas de vidro foram utilizadas para colonização das algas perifíticas, e as amostragens foram feitas entre o 15° e o 31° dia de sucessão. Pela Análise de Correspondência Canônica, pode-se observar uma clara separação entre os tratamentos devido à temperatura e adição de nutrientes. A diminuição de temperatura afetou a abundância das classes de algas perifíticas, principalmente pela redução da densidade relativa de Cyanophyceae e aumento de Zygnemaphyceae. O enriquecimento artificial de nutrientes, principalmente P, alterou a estrutura da comunidade de algas perifíticas, em termos de densidade das classes algais. As densidades relativas das classes, em geral, aumentaram com a adição de nutrientes. O fósforo pode ser considerado direcionador na densidade das algas perifíticas, como pode ser observado pela rápida resposta após os enriquecimentos artificiais.This study set out to evaluate, via a mesocosm experiment, the influence of the temperature and concentration of nutrients (N and P in the abundance of periphytic algae (except Bacillariophyceae of the upper Paraná river floodplain. The experiment was designed using 5 treatments: a control (C, added nutrients (P+, N+, NP+ at 25°C, and without added nutrients at 15°C. Glass slides were used for periphytic algae colonization, and the samples were taken on the 15th and 31st days following colonization. Canonical Correspondence Analysis revealed a clear separation among treatment groups due to temperature and added nutrients. A decrease

  13. Content of some anti-nutrients and nutrients in some new plant ...

    African Journals Online (AJOL)

    Eight edible plant foods have been analyzed in order to detect differences in nutritional quality, considering the balance between nutrients and anti-nutrient compounds present in each. The most important nutrients studied in this paper were: water, starch, free sugars, such as glucose, fructose and sucrose.

  14. Microbial enzyme activity, nutrient uptake and nutrient limitation in forested streams

    Science.gov (United States)

    Brian H. Hill; Frank H. McCormick; Bret C. Harvey; Sherri L. Johnson; Melvin L. Warren; Colleen M. Elonen

    2010-01-01

    The flow of organic matter and nutrients from catchments into the streams draining them and the biogeochemical transformations of organic matter and nutrients along flow paths are fundamental processes instreams (Hynes,1975; Fisher, Sponseller & Heffernan, 2004). Microbial biofilms are often the primary interface for organic matter and nutrient uptake and...

  15. Additive Similarity Trees

    Science.gov (United States)

    Sattath, Shmuel; Tversky, Amos

    1977-01-01

    Tree representations of similarity data are investigated. Hierarchical clustering is critically examined, and a more general procedure, called the additive tree, is presented. The additive tree representation is then compared to multidimensional scaling. (Author/JKS)

  16. Additive Manufacturing Infrared Inspection

    Science.gov (United States)

    Gaddy, Darrell; Nettles, Mindy

    2015-01-01

    The Additive Manufacturing Infrared Inspection Task started the development of a real-time dimensional inspection technique and digital quality record for the additive manufacturing process using infrared camera imaging and processing techniques. This project will benefit additive manufacturing by providing real-time inspection of internal geometry that is not currently possible and reduce the time and cost of additive manufactured parts with automated real-time dimensional inspections which deletes post-production inspections.

  17. Impact of simulated atmospheric nitrogen deposition on nutrient cycling and carbon sink via mycorrhizal fungi in two nutrient-poor peatlands

    Science.gov (United States)

    Larmola, Tuula; Kiheri, Heikki; Bubier, Jill L.; van Dijk, Netty; Dise, Nancy; Fritze, Hannu; Hobbie, Erik A.; Juutinen, Sari; Laiho, Raija; Moore, Tim R.; Pennanen, Taina

    2017-04-01

    Peatlands store one third of the global soil carbon (C) pool. Long-term fertilization experiments in nutrient-poor peatlands showed that simulated atmospheric nitrogen (N) deposition does not enhance ecosystem C uptake but reduces C sink potential. Recent studies have shown that a significant proportion of C input to soil in low-fertility forests entered the soil through mycorrhizal fungi, rather than as plant litter. Is atmospheric N deposition diminishing peatland C sink potential due to the suppression of ericoid mycorrhizal fungi? We studied how nutrient addition influences plant biomass allocation and the extent to which plants rely on mycorrhizal N uptake at two of the longest-running nutrient addition experiments on peatlands, Whim Bog, United Kingdom, and Mer Bleue Bog, Canada. We determined the peak growing season aboveground biomass production and coverage of vascular plants using the point intercept method. We also analyzed isotopic δ15N patterns and nutrient contents in leaves of dominant ericoid mycorrhizal shrubs as well as the non-mycorrhizal sedge Eriophorum vaginatum under different nutrient addition treatments. The treatments receive an additional load of 1.6-6.4 N g m-2 y-1 either as ammonium (NH4) nitrate (NO3) or NH4NO3 and with or without phosphorus (P) and potassium (K), alongside unfertilized controls. After 11-16 years of nutrient addition, the vegetation structure had changed remarkably. Ten of the eleven nutrient addition treatments showed an increase of up to 60% in total vascular plant abundance. Only three (NH4Cl, NH4ClPK, NaNO3PK) of the nutrient addition treatments showed a concurrent decrease of down to 50% in the relative proportion of ericoid mycorrhizal shrubs to total vascular plant abundance. The response to nutrient load may be explained by the water table depth, the form of N added and whether N was added with PK. Shrubs were strong competitors at the dry Mer Bleue bog while sedges gained in abundance at the wetter Whim bog

  18. Nutrient reduction in rations with phytase for growing pigs Redução de nutrientes em rações com fitase para suínos em crescimento

    Directory of Open Access Journals (Sweden)

    Valéria Vânia Rodrigues

    2011-02-01

    Full Text Available Two experiments were conducted to evaluate the performance, the energy and nutrient balance and economic viability of production of growing pigs fed diets with reduced levels and phytase. In experiment 1, 60 barrows and gilts (initial weight 25 ± 1.72 kg were housed in a randomized block design with three diets, ten replicates and two animals per experimental unit (one male and one female. One of the diets was formulated with a reduced level with phytase and evaluated in comparison to a positive-control diet that was formulated according to the nutritional recommendations for animals of this breed, and a negative-control diet without phytase. The different diets did not affect feed intake, but the diet with phytase promoted better final weight, daily weight gain and feed conversion, although it did not differ from the positive control diet. In experiment 2, 27 barrows (initial weight 49 ± 3.67 kg were housed in random blocks with three diets and nine replicates with experimental plot represented by one animal. The diets did not affect the balance of energy and nutrients but had a significant effect on the efficiency of utilization of calcium and phosphorus, which was the lowest in animals that received the positive-control diet. Economic viability improved when nutrients were reduced and phytase was added in the ration. The addition of phytase (500 ftu/kg in rations formulated with nutritional levels reduced for growing swines improves rearing productivity and it is economical viable.Dois experimentos foram conduzidos para avaliar o desempenho, o balanço de energia e nutrientes e a viabilidade econômica da produção de suínos em crescimento alimentados com rações com níveis reduzidos e fitase. No experimento 1, 60 suínos machos castrados e fêmeas (peso inicial de 25 ± 1,72 kg foram alojados em delineamento de blocos casualizados, com três dietas, dez repetições e dois animais por unidade experimental (macho e fêmea. Uma das

  19. Phytoplankton cell size reduction in response to warming mediated by nutrient limitation.

    Directory of Open Access Journals (Sweden)

    Kalista Higini Peter

    Full Text Available Shrinking of body size has been proposed as one of the universal responses of organisms to global climate warming. Using phytoplankton as an experimental model system has supported the negative effect of warming on body-size, but it remains controversial whether the size reduction under increasing temperatures is a direct temperature effect or an indirect effect mediated over changes in size selective grazing or enhanced nutrient limitation which should favor smaller cell-sizes. Here we present an experiment with a factorial combination of temperature and nutrient stress which shows that most of the temperature effects on phytoplankton cell size are mediated via nutrient stress. This was found both for community mean cell size and for the cell sizes of most species analyzed. At the highest level of nutrient stress, community mean cell size decreased by 46% per °C, while it decreased only by 4.7% at the lowest level of nutrient stress. Individual species showed qualitatively the same trend, but shrinkage per °C was smaller. Overall, our results support the hypothesis that temperature effects on cell size are to a great extent mediated by nutrient limitation. This effect is expected to be exacerbated under field conditions, where higher temperatures of the surface waters reduce the vertical nutrient transport.

  20. Testing the stress gradient hypothesis in herbivore communities facilitation peaks at intermediate nutrient levels.

    Science.gov (United States)

    Bakker, Elisabeth S; Dobrescu, Ioana; Straile, Dietmar; Holmgren, Milena

    2013-08-01

    The role of positive interactions in structuring plant and animal communities is increasingly recognized, but the generality of current theoretical models has remained practically unexplored in animal communities. The stress gradient hypothesis predicts a linear increase in the intensity of facilitation as environmental conditions become increasingly stressful, whereas other theoretical models predict a maximum at intermediate environmental stress. We tested how competition and facilitation between herbivores change over a manipulated gradient of nutrient availability. We studied the effect of grazing by pond snails (Lymnaea stagnalis L.) as bulk grazers on aquatic caterpillars (Acentria ephemerella Denis and Schiffermüller) as small specialist grazers along an experimental gradient of environmental nutrient concentration. Higher nutrient levels increased overall total plant biomass but induced a shift toward dominance of filamentous algae at the expense of macrophytes. Facilitation of caterpillars by snail presence peaked at intermediate nutrient levels. Both caterpillar biomass and caterpillar grazing on macrophytes were highest at intermediate nutrient levels. Snails facilitated caterpillars possibly by removing filamentous algae and increasing access to the macrophyte resource, whereas they did not affect macrophyte biomass or C: nutrient ratios, a measure of food quality. We conclude that competition and facilitation in herbivore communities change along nutrient availability gradients that affect plant biomass and community composition. Understanding how interspecific interactions may change in strength and direction along environmental gradients is important to predict how the diversity and structure of communities may respond to the introduction or removal of herbivore species in ecosystems.

  1. Evolution of solidification texture during additive manufacturing

    National Research Council Canada - National Science Library

    Wei, H L; Mazumder, J; DebRoy, T

    2015-01-01

    Striking differences in the solidification textures of a nickel based alloy owing to changes in laser scanning pattern during additive manufacturing are examined based on theory and experimental data...

  2. Food additives and Hymenolepis nana infection: an experimental study.

    Science.gov (United States)

    El-Nouby, Kholoud A; Hamouda, Hala E; Abd El Azeem, Mona A; El-Ebiary, Ahmad A

    2009-12-01

    The effect of sodium benzoate (SB) on the pathogenesis of Hymenolepis nana (H. nana) and its neurological manifestations was studied in the present work. One hundred and thirty five mice were classified into three groups. GI: received SB alone. GII: received SB before & after infection with H. nana and GIII: infected with H. nana. All groups were subjected to parasitological, histopathological, immunohistochemical and biochemical assays. The results revealed a significant decrease in IL-4 serum level with a significant increase in gamma amino butyric acid (GABA) and decrease in zinc brain levels in GI, while GII showed non significant increase in IL-4 level that resulted in a highly significant increase in the mean number of cysticercoids and adult worms with delayed expulsion as compared to GIII. This was reflected on histopathological and immunohistochemical changes in the brain. Also, there was a highly significant increase in GABA and decrease in zinc brain levels in GII to the degree that induced behavioral changes. This emphasizes the possible synergistic effect of SB on the neurological manifestations of H. nana and could, in part, explain the increased incidence of behavioral changes in children exposed to high doses of SB and unfortunately have H. nana infection.

  3. Closed-Cycle Nutrient Supply For Hydroponics

    Science.gov (United States)

    Schwartzkopf, Steven H.

    1991-01-01

    Hydroponic system controls composition and feed rate of nutrient solution and recovers and recycles excess solution. Uses air pressure on bladders to transfer aqueous nutrient solution. Measures and adjusts composition of solution before it goes to hydroponic chamber. Eventually returns excess solution to one of tanks. Designed to operate in microgravity, also adaptable to hydroponic plant-growing systems on Earth.

  4. Nutrient Dynamics and Litter Decomposition in Leucaena ...

    African Journals Online (AJOL)

    komla

    Energy flow and nutrient cycling are essential for the functioning of an ... biochemical (i.e. intra system) nutrient cycling and food webs; this refers to both the physical and ..... (1998) suggested that microbial activity could be limited by litter moisture .... Energy storage and the balance of producers and decomposers on ...

  5. LITTERFALL AND NUTRIENT RETURNS IN ISOLATED STANDS ...

    African Journals Online (AJOL)

    Dr Osondu

    and branch morphology, leaf size and arrangement. The main objective of this study was to examine litter production and nutrient returns through litterfall by isolated stands of Terminalia catappa, and determine the contributions of nutrient elements to the rainforest soil by the isolated exotic, through a direct comparison with.

  6. LITTERFALL AND NUTRIENT RETURNS IN ISOLATED STANDS ...

    African Journals Online (AJOL)

    Dr Osondu

    Keywords: Litterfall, Nutrient returns, Seasonal variation, Southern Nigeria, Terminalia catappa, Tropical rainforest. Introduction. In the tropical rainforests, plants and soils are in equilibrium involving an almost closed cycling of nutrients which is achieved by a very high rate of litter production, rapid mineralization and a.

  7. Water Quality Protection from Nutrient Pollution: Case ...

    Science.gov (United States)

    Water bodies and coastal areas around the world are threatened by increases in upstream sediment and nutrient loads, which influence drinking water sources, aquatic species, and other ecologic functions and services of streams, lakes, and coastal water bodies. For example, increased nutrient fluxes from the Mississippi River Basin have been linked to increased occurrences of seasonal hypoxia in northern Gulf of Mexico. Lake Erie is another example where in the summer of 2014 nutrients, nutrients, particularly phosphorus, washed from fertilized farms, cattle feedlots, and leaky septic systems; caused a severe algae bloom, much of it poisonous; and resulted in the loss of drinking water for a half-million residents. Our current management strategies for point and non-point source nutrient loadings need to be improved to protect and meet the expected increased future demands of water for consumption, recreation, and ecological integrity. This presentation introduces management practices being implemented and their effectiveness in reducing nutrient loss from agricultural fields, a case analysis of nutrient pollution of the Grand Lake St. Marys and possible remedies, and ongoing work on watershed modeling to improve our understanding on nutrient loss and water quality. Presented at the 3rd International Conference on Water Resource and Environment.

  8. Tree root systems and nutrient mobilization

    DEFF Research Database (Denmark)

    Boyle, Jim; Rob, Harrison; Raulund-Rasmussen, Karsten

    of nutrient elements essential for forest growth and resilience. Research and techniques have signifi cantly advanced since Olof Tamm’s 1934 base mineral index for Swedish forest soils, and basic nutrient budget estimates for whole-tree harvesting systems of the 1970s. Recent research in areas that include...

  9. Trichoderma -mediated enhancement of nutrient uptake and ...

    African Journals Online (AJOL)

    Trichoderma harzianum is a naturally occurring filamentous fungus which solubilizes mineral nutrients and inorganic fertilizers, increasing availability and uptake of nutrients to the plant. Rhizoctonia solani is a major problem for seedlings, causing damping-off and in mature plants causing foot and root rot in the tomato crop, ...

  10. Complementary Feeding Practices And Nutrient Intake From ...

    African Journals Online (AJOL)

    Complementary Feeding Practices And Nutrient Intake From Habitual Complementary Foods Of Infants And Children Aged 6-18 Months Old In Lusaka, Zambia. ... Compared with the recommended daily allowance (RDA) at 6-8, 9-11 and 12-18 months of age, the daily nutrient intakes were 88%, 121% and 94% for energy ...

  11. Photosynthetic performance, epiphyte biomass and nutrient content ...

    African Journals Online (AJOL)

    Heavy nutrient loads in coastal waters often lead to excessive growth of microalgal and macroalgal epiphytes on seagrass leaves, with varying effects on the underlying seagrasses. This study evaluates the photosynthetic performance, epiphytic biomass and tissue nutrient content of two tropical seagrasses, Cymodocea ...

  12. Efeito da adição de precursores na produção de alcaloide anticancerígeno usando a técnica de planejamento experimental Effect of the precursor addition on the anticancer alkaloid production using experimental design methodology

    Directory of Open Access Journals (Sweden)

    Oselys Rodriguez Justo

    2009-01-01

    Full Text Available The effect of precursors on the anticancer alkaloid production by submerged fermentation using M. anisopliae 3935 was studied, according to complete experimental design 2² with three central points. The results showed that lysine was the most important variable, however, when both lysine and glucose were added to the fermentation medium, the alkaloid production reached, approximately, 17 mg L-1 after 120 hours of fermentation. Then, the scale-up of the process was carried out and these results were confirmed. Finally, 35 mg L-1 of alkaloid at 192 h were attained after increment of added aminoacid lysine.

  13. Influence of Physiological Stress on Nutrient Stoichiometry in Larval Amphibians.

    Science.gov (United States)

    Kirschman, Lucas J; Haslett, Savhannah; Fritz, Kelley A; Whiles, Matt R; Warne, Robin W

    2016-01-01

    Exposure to environmental stressors alters animal phenotypes as well as nutrient metabolism, assimilation, and excretion. While stress-induced shifts in nutrient processes are known to alter organismal carbon (C) and nitrogen (N) stoichiometry, there has been little exploration of how environmental factors influence phosphorous (P). A better understanding of how P cycling varies with animal physiological state may provide insight into across-scale processes, because P is essential to animal function and ecological processes such as production and decomposition. We tested the effects of predator stress and exogenous glucocorticoids on C∶N∶P stoichiometry of larval amphibians. Glucocorticoids altered nutrient stoichiometry, apparently by modulating ossification and renal function. This reduced whole-body P and significantly increased N∶P. Additionally, elevated glucocorticoids caused a long-term reduction in P excretion. This reduction may reflect an initial unmeasured loss of P that glucocorticoids induce over acute timescales. In contrast, exposure to predator cues had no effect on larval C∶N∶P stoichiometry, which highlights that different stressors have varied effects on the endocrine stress response. Predation, in particular, is ubiquitous in the environment; thus, larvae responding to predators have conserved mechanisms that likely prevent or minimize physiological disruption. These results demonstrate the differing physiological roles of N and P, distinct nutrient demands associated with amphibian metamorphosis, and the contrasting effects that different environmental factors have on the physiological stress response. Our results also suggest that anthropogenic changes to the environment that induce chronic stress in amphibians could affect the biogeochemistry of nutrient-poor environments where they may act as keystone species.

  14. Nutrient dynamics and primary production in a pristine coastal mangrove ecosystem: Andaman Islands, India

    Science.gov (United States)

    Jenkins, E. N.; Nickodem, K.; Siemann, A. L.; Hoeher, A.; Sundareshwar, P. V.; Ramesh, R.; Purvaja, R.; Banerjee, K.; Manickam, S.; Haran, H.

    2012-12-01

    Mangrove ecosystems play a key role in supporting coastal food webs and nutrient cycles in the coastal zone. Their strategic position between the land and the sea make them important sites for land-ocean interaction. As part of an Indo-US summer field course we investigated changes in the water chemistry in a pristine mangrove creek located at Wright Myo in the Andaman Islands, India. This study was conducted during the wet season (June 2012) to evaluate the influence of the coastal mangrove wetlands on the water quality and productivity in adjoining pelagic waters. Over a full tidal cycle spanning approximately 24 hrs, we measured nutrient concentrations and other ancillary parameters (e.g. dissolved oxygen, turbidity, salinity, etc.) hourly to evaluate water quality changes in incoming and ebbing tides. Nutrient analyses had the following concentration ranges (μM): nitrite 0.2-0.9, nitrate 2.0-11.5, ammonium 1.3-7.5, dissolved inorganic phosphate 0.7-2.8. The dissolved inorganic nitrogen to dissolved inorganic phosphate (DIN/DIP) ratio was very low relative to an optimal ratio, suggesting growth is nitrogen limited. In addition, we conducted primary production assays to investigate the factors that controlled primary production in this pristine creek. The experiment was carried out in situ using the Winkler method at low and high tide. Four-hour incubation of light and dark bottles representing a fixed control, non-fertilized, fertilized with nitrate, and fertilized with phosphate enabled the measurement of both net oxygen production and dark respiration. The low tide experiment suggests the ecosystem is heterotrophic because the oxygen measured in the light bottles was consistently less than that of the dark bottles. This result may be an experimental artifact of placing the glass bottles in the sun for too long prior to incubation, potentially leading to photolysis of large organic molecules in the light bottles. The high tide experiment also displayed

  15. Engineering crop nutrient efficiency for sustainable agriculture.

    Science.gov (United States)

    Chen, Liyu; Liao, Hong

    2017-10-01

    Increasing crop yields can provide food, animal feed, bioenergy feedstocks and biomaterials to meet increasing global demand; however, the methods used to increase yield can negatively affect sustainability. For example, application of excess fertilizer can generate and maintain high yields but also increases input costs and contributes to environmental damage through eutrophication, soil acidification and air pollution. Improving crop nutrient efficiency can improve agricultural sustainability by increasing yield while decreasing input costs and harmful environmental effects. Here, we review the mechanisms of nutrient efficiency (primarily for nitrogen, phosphorus, potassium and iron) and breeding strategies for improving this trait, along with the role of regulation of gene expression in enhancing crop nutrient efficiency to increase yields. We focus on the importance of root system architecture to improve nutrient acquisition efficiency, as well as the contributions of mineral translocation, remobilization and metabolic efficiency to nutrient utilization efficiency. © 2017 Institute of Botany, Chinese Academy of Sciences.

  16. Systematically enhanced subarctic Pacific stratification and nutrient utilization during glacials

    Science.gov (United States)

    Knudson, K. P.; Ravelo, A. C.

    2015-12-01

    inhibits nutrient upwelling, became the dominant control on biological productivity. Additionally, nitrate utilization (and thus stratification) is in phase with pCO2 minima, implying that strong glacial stratification may have provided an important climate feedback by reducing oceanic CO2 "leakage" to the atmosphere.

  17. Effects of feeding sugar beets, ensiled with or without an additive, on the performance of dairy cows

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Messerschmidt, Ulrike; Larsen, Mogens

    2017-01-01

    The objective of this study was to examine the nutritional composition and quality of beet silages ensiled without (SBS–) and with silage additive (SBS+) and the effect on nutrient intake, milk yield, and milk composition when maize silage was replaced with SBS+ or SBS–. SBS– ferment heavily......, and the main fermentation products are ethanol, lactic acid, and acetic acid. Adding a silage additive restricts fermentation and preserves most of the sugar in SBS+. Forty-two Holstein cows were used in a multiple 3 × 3 Latin square design. Each experimental period consisted of two weeks adaptation and one...... to fewer visits to the milking robot and thus less concentrate intake in DSBS+. The results show that sugar beets ensiled wet, without silage additive, is a promising feed for lactating cows....

  18. Identity of the Growth-Limiting Nutrient Strongly Affects Storage Carbohydrate Accumulation in Anaerobic Chemostat Cultures of Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Hazelwood, L.A.; Walsh, M.C.; Luttik, M.A.H.; Daran-Lapujade, P.; Pronk, J.T.; Daran, J.M.

    2009-01-01

    OA Fund TU Delft Accumulation of glycogen and trehalose in nutrient-limited cultures of Saccharomyces cerevisiae is negatively correlated with the specific growth rate. Additionally, glucose-excess conditions (i.e., growth limitation by nutrients other than glucose) are often implicated in

  19. Nutrient Content and pH of Honey Propolis Trigona from Masamba, South Sulawesi Indonesia

    OpenAIRE

    Andi Nilawati Usman; Yuliana Syam; Rosdiana Natzir; Sutji Pratiwi Rahardjo; Muhammad Hatta; Indah Raya; Yuyun Widaningsih; Andi Zulkifli Abdullah; Ainurafiq Ainurafiq

    2016-01-01

    Honey and propolis have nutritional components that are beneficial to health, but data concerning nutrient components of honey mixed propolis is still lacking. This study aims to determine the nutrient components and PH honey given addition of propolis, that is honey propolis from Masamba Trigona bees, South Sulawesi, Indonesia. This type of research is laboratory research with sample85 grams Trigona honey mixed with 15 gram Propolis Trigona. The results showed that honey propolis Trigona of...

  20. ROOT MORPHOLOGY AND NUTRIENT UPTAKE KINETICS BY AUSTRALIAN CEDAR CLONES

    Directory of Open Access Journals (Sweden)

    RAQUEL OLIVEIRA BATISTA

    2016-01-01

    Full Text Available Evaluation of root morphology and kinetic parameters assist in the characterization of genotypes in nutrient uptake efficiency. This study characterized Australian cedar clones concerning their nutrient uptake capacity at the seedling stage through root morphology and the kinetics of P, K, Ca, and Mg uptake. The experiment was conducted using a nutrient solution in a greenhouse and growth chamber. Four Australian cedar clones (HE, XF, XD, and XE, provided by Bela Forest View ( Empresa Florestal Bela Vista , were tested using a completely randomized design with five repetitions, totaling 20 experimental plots. The length, volume, surface area, average diameter, and root length per diameter class, as well as the uptake parameters V max , K m , C min , and the estimated inflow of P, K, Ca, and Mg, were determined. The root morphological characteristics varied between Australian cedar clones; clone XD exhibited the largest root system development. The uptake efficiency of P, K, Ca, and Mg varied between cedar Australian clones. When availability differed, clones XE and XF exhibited greater plasticity in the uptake of P and K respectively, and similar results were found for clone HE in the uptake of Ca and Mg.

  1. Growth and physiology of aspen supplied with different fertilizer addition rates

    Science.gov (United States)

    Mark D. Coleman; Richard E. Dickson; J.G. Isebrands

    1998-01-01

    Variable internal plant nutrient content may confound plant response to environmental stress. Plant nutrient content may be controlled with relative addition rate techniques in solution culture. However, because raising large numbers of plants in flowing solution culture is difficult. we investieated the feasibility of raisine plants in soil mix using relative...

  2. The potential of freshwater macroalgae as a biofuels feedstock and the influence of nutrient availability on freshwater macroalgal biomass production

    Science.gov (United States)

    Yun, Jin-Ho

    Extensive efforts have been made to evaluate the potential of microalgae as a biofuel feedstock during the past 4-5 decades. However, filamentous freshwater macroalgae have numerous characteristics that favor their potential use as an alternative algal feedstock for biofuels production. Freshwater macroalgae exhibit high rates of areal productivity, and their tendency to form dense floating mats on the water surface imply significant reductions in harvesting and dewater costs compared to microalgae. In Chapter 1, I reviewed the published literature on the elemental composition and energy content of five genera of freshwater macroalgae. This review suggested that freshwater macroalgae compare favorably with traditional bio-based energy sources, including terrestrial residues, wood, and coal. In addition, I performed a semi-continuous culture experiment using the common Chlorophyte genus Oedogonium to investigate whether nutrient availability can influence its higher heating value (HHV), productivity, and proximate analysis. The experimental study suggested that the most nutrient-limited growth conditions resulted in a significant increase in the HHV of the Oedogonium biomass (14.4 MJ/kg to 16.1 MJ/kg). Although there was no significant difference in productivity between the treatments, the average dry weight productivity of Oedogonium (3.37 g/m2/day) was found to be much higher than is achievable with common terrestrial plant crops. Although filamentous freshwater macroalgae, therefore, have significant potential as a renewable source of bioenergy, the ultimate success of freshwater macroalgae as a biofuel feedstock will depend upon the ability to produce biomass at the commercial-scale in a cost-effective and sustainable manner. Aquatic ecology can play an important role to achieve the scale-up of algal crop production by informing the supply rates of nutrients to the cultivation systems, and by helping to create adaptive production systems that are resilient to

  3. Real-time nutrient monitoring in rivers: adaptive sampling strategies, technological challenges and future directions

    Science.gov (United States)

    Blaen, Phillip; Khamis, Kieran; Lloyd, Charlotte; Bradley, Chris

    2016-04-01

    Excessive nutrient concentrations in river waters threaten aquatic ecosystem functioning and can pose substantial risks to human health. Robust monitoring strategies are therefore required to generate reliable estimates of river nutrient loads and to improve understanding of the catchment processes that drive spatiotemporal patterns in nutrient fluxes. Furthermore, these data are vital for prediction of future trends under changing environmental conditions and thus the development of appropriate mitigation measures. In recent years, technological developments have led to an increase in the use of continuous in-situ nutrient analysers, which enable measurements at far higher temporal resolutions than can be achieved with discrete sampling and subsequent laboratory analysis. However, such instruments can be costly to run and difficult to maintain (e.g. due to high power consumption and memory requirements), leading to trade-offs between temporal and spatial monitoring resolutions. Here, we highlight how adaptive monitoring strategies, comprising a mixture of temporal sample frequencies controlled by one or more 'trigger variables' (e.g. river stage, turbidity, or nutrient concentration), can advance our understanding of catchment nutrient dynamics while simultaneously overcoming many of the practical and economic challenges encountered in typical in-situ river nutrient monitoring applications. We present examples of short-term variability in river nutrient dynamics, driven by complex catchment behaviour, which support our case for the development of monitoring systems that can adapt in real-time to rapid environmental changes. In addition, we discuss the advantages and disadvantages of current nutrient monitoring techniques, and suggest new research directions based on emerging technologies and highlight how these might improve: 1) monitoring strategies, and 2) understanding of linkages between catchment processes and river nutrient fluxes.

  4. Ultrasonic waste activated sludge disintegration for recovering multiple nutrients for biofuel production.

    Science.gov (United States)

    Xie, Guo-Jun; Liu, Bing-Feng; Wang, Qilin; Ding, Jie; Ren, Nan-Qi

    2016-04-15

    Waste activated sludge is a valuable resource containing multiple nutrients, but is currently treated and disposed of as an important source of pollution. In this work, waste activated sludge after ultrasound pretreatment was reused as multiple nutrients for biofuel production. The nutrients trapped in sludge floc were transferred into liquid medium by ultrasonic disintegration during first 30 min, while further increase of pretreatment time only resulted in slight increase of nutrients release. Hydrogen production by Ethanoligenens harbinense B49 from glucose significantly increased with the concentration of ultrasonic sludge, and reached maximum yield of 1.97 mol H2/mol glucose at sludge concentration of 7.75 g volatile suspended solids/l. Without addition of any other chemicals, waste molasses rich in carbohydrate was efficiently turned into hydrogen with yield of 189.34 ml H2/g total sugar by E. harbinense B49 using ultrasonic sludge as nutrients. The results also showed that hydrogen production using pretreated sludge as multiple nutrients was higher than those using standard nutrients. Acetic acid produced by E. harbinense B49 together with the residual nutrients in the liquid medium were further converted into hydrogen (271.36 ml H2/g total sugar) by Rhodopseudomonas faecalis RLD-53 through photo fermentation, while ethanol was the sole end product with yield of 220.26 mg/g total sugar. Thus, pretreated sludge was an efficient nutrients source for biofuel production, which could replace the standard nutrients. This research provided a novel strategy to achieve environmental friendly sludge disposal and simultaneous efficient biofuel recovery from organic waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Nutrients and other abiotic factors affecting bacterial communities in an Ohio River (USA).

    Science.gov (United States)

    Rubin, Melissa A; Leff, Laura G

    2007-08-01

    Nitrogen and phosphorus additions from anthropogenic sources can alter the nutrient pool of aquatic systems, both through increased nutrient concentrations and changes in stoichiometry. Because bacteria are important in nutrient cycling and aquatic food webs, information about how nutrients affect bacterial communities enhances our understanding of how changes in nutrient concentrations and stoichiometry potentially affect aquatic ecosystems as a whole. In this study, bacterial communities were examined in biofilms from cobbles collected across seasons at three sites along the Mahoning River (Ohio) with differing levels of inorganic nutrient inputs. Members of the alpha-, beta-, and gamma-proteobacteria, the Cytophaga-Flavobacteria cluster, and the Domain Bacteria were enumerated using fluorescent in situ hybridization. Detrended canonical correspondence analysis (DCCA) revealed that stoichiometric ratios, especially the dissolved inorganic nitrogen (DIN):soluble reactive phosphorus (SRP) molar ratio (NO(2)/NO(3) + NH(4):soluble reactive phosphorus), were correlated with abundance of the various bacterial taxa. However, the patterns were complicated by correlations with single nutrient concentrations and seasonal changes in temperature. Seasonal cycles appeared to play an important role in structuring the community, as there were distinct winter communities and temperature was negatively correlated with abundance of both alpha-proteobacteria and Cytophaga-Flavobacteria. However, nutrients and stoichiometry also appeared to affect the community. Numbers of cells hybridizing the Domain Bacteria probe were correlated with the DOC:DIN ratio, the beta-proteobacteria had a negative correlation with soluble reactive phosphorus concentrations and a positive correlation with the DIN:SRP ratio, and the Cytophaga-Flavobacteria had a significant negative partial correlation with the DIN:SRP ratio. Abundances of the alpha- or gamma-proteobacteria were not directly correlated to

  6. Effects of raw and diluted municipal sewage effluent with micronutrient foliar sprays on the growth and nutrient concentration of foxtail millet in southeast Iran.

    Science.gov (United States)

    Asgharipour, Mohammad Reza; Reza Azizmoghaddam, Hamid

    2012-10-01

    In this study, the effect of irrigation with raw or diluted municipal sewage effluent accompanied by foliar micronutrient fertilizer sprays was examined on the growth, dry matter accumulation, grain yield, and mineral nutrients in foxtail millet plants. The experimental design was a split plot with three irrigation sources: raw sewage, 50% diluted sewage, and well water comprising the main treatments, and four combinations of Mn and Zn foliar sprays as sub-treatments that were applied with four replications. The experiment was conducted in 2009 at the Zabol University research farm in Zabol, south Iran. The applied municipal sewage effluent contained higher levels of micronutrients and macronutrients and exhibited greater degrees of electrical conductivity compared to well water. Because of the small scale of industrial activities in Zabol, the amount of heavy metals in the sewage was negligible (below the limits set for irrigation water in agricultural lands); these contaminants would not be severely detrimental to crop growth. The experimental results indicated that irrigation of plants with raw or diluted sewage stimulates the measured growth and productivity parameters of foxtail millet plants. The concentrations of micronutrients and macronutrients were also positively affected. These stimulations were attributed to the presence of high levels of such essential nutrients as N, P, and organic matter in wastewater. Supplied in sewage water alone, Mn and Zn were not able to raise the productivity of millet to the level obtained using fertilizers at the recommended values; this by itself indicated that additional nutrients from fertilizers are required to obtain higher levels of millet productivity with sewage farming. Despite the differences in nutrient concentrations among the different irrigation water sources, the micronutrient foliar sprays did not affect the concentrations of micronutrients and macronutrients in foxtail millet plants. These results suggested

  7. Additives in yoghurt production

    Directory of Open Access Journals (Sweden)

    Milna Tudor

    2008-02-01

    Full Text Available In yoghurt production, mainly because of sensory characteristics, different types of additives are used. Each group, and also each substance from the same group has different characteristics and properties. For that reason, for improvement of yoghurt sensory characteristics apart from addition selection, the quantity of the additive is very important. The same substance added in optimal amount improves yoghurt sensory attributes, but too small or too big addition can reduce yoghurt sensory attributes. In this paper, characteristics and properties of mostly used additives in yoghurt production are described; skimmed milk powder, whey powder, concentrated whey powder, sugars and artificial sweeteners, fruits, stabilizers, casein powder, inulin and vitamins. Also the impact of each additive on sensory and physical properties of yoghurt, syneresis and viscosity, are described, depending on used amount added in yoghurt production.

  8. Cation Uptake and Allocation by Red Pine Seedlings under Cation-Nutrient Stress in a Column Growth Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhenqing; Balogh-Brunstad, Zsuzsanna; Grant, Michael R.; Harsh, James B.; Gill, Richard; Thomashow, Linda; Dohnalkova, Alice; Stacks, Daryl; Letourneau, Melissa; Keller, Chester K.

    2014-01-10

    Background and Aims Plant nutrient uptake is affected by environmental stress, but how plants respond to cation-nutrient stress is poorly understood. We assessed the impact of varying degrees of cation-nutrient limitation on cation uptake in an experimental plant-mineral system. Methods Column experiments, with red pine (Pinus resinosa Ait.) seedlings growing in sand/mineral mixtures, were conducted for up to nine months under a range of Ca- and K-limited conditions. The Ca and K were supplied from both minerals and nutrient solutions with varying Ca and K concentrations. Results Cation nutrient stress had little impact on carbon allocation after nine months of plant growth and K was the limiting nutrient for biomass production. The Ca/Sr and K/Rb ratio results allowed independent estimation of dissolution incongruency and discrimination against Sr and Rb during cation uptake processes. The fraction of K in biomass from biotite increased with decreasing K supply from nutrient solutions. The mineral anorthite was consistently the major source of Ca, regardless of nutrient treatment. Conclusions Red pine seedlings exploited more mineral K in response to more severe K deficiency. This did not occur for Ca. Plant discrimination factors must be carefully considered to accurately identify nutrient sources using cation tracers.

  9. Wire + Arc Additive Manufacturing

    OpenAIRE

    Williams, Stewart W.; Martina, Filomeno; Addison, Adrian C.; Ding, Jialuo; Pardal, Goncalo; Colegrove, Paul A.

    2016-01-01

    Depositing large components (>10 kg) in titanium, aluminium, steel and other metals is possible using Wire + Arc Additive Manufacturing. This technology adopts arc welding tools and wire as feedstock for additive manufacturing purposes. High deposition rates, low material and equipment costs, and good structural integrity make Wire+Arc Additive Manufacturing a suitable candidate for replacing the current method of manufacturing from solid billets or large forgings, especially with regards to ...

  10. Nutrient Acquisition and Metabolism by Campylobacter jejuni

    Directory of Open Access Journals (Sweden)

    Martin eStahl

    2012-02-01

    Full Text Available The gastrointestinal pathogen Campylobacter jejuni is able to colonize numerous different hosts and compete against the gut microbiota. To do this, it must be able to efficiently acquire sufficient nutrients from its environment to support its survival and rapid growth in the intestine. However, despite almost 50 years of research, many aspects as to how C. jejuni accomplishes this feat remain poorly understood. C. jejuni lacks many of the common metabolic pathways necessary for the use of glucose, galactose, or other carbohydrates upon which most other microbes thrive. It does however make efficient use of citric acid cycle intermediates and various amino acids. C. jejuni readily uses the amino acids aspartate, glutamate, serine, and proline, with certain strains also possessing additional pathways allowing for the use of glutamine and asparagine. More recent work has revealed that some C. jejuni strains can metabolize the sugar L-fucose. This finding has upset years of dogma that C. jejuni is an asaccharolytic organism. C. jejuni also possesses diverse mechanisms for the acquisition of various transition metals that are required for metabolic activities. In particular, iron acquisition is critical for the formation of iron-sulphur complexes. C. jejuni is also unique in possessing both molybdate and tungsten cofactored proteins and thus has an unusual regulatory scheme for these metals. Together these various metabolic and acquisition pathways help C. jejuni to compete and thrive in wide variety of hosts and environments.

  11. Reposição de nutrientes em solução nutritiva para o cultivo hidropônico de alface Nutrients replacement in nutrient solution for lettuce hydroponic cultivation

    Directory of Open Access Journals (Sweden)

    Fernanda Alice Antonello Londero Backes

    2004-10-01

    Full Text Available Este trabalho teve como objetivos comparar a produção de alface sob diferentes métodos de reposição de nutrientes em soluções renovadas a cada cultivo, bem como avaliar a utilização da mesma solução, com reposição de nutrientes, durante três cultivos consecutivos. O experimento foi realizado em casa-de-vegetação da Universidade Federal de Santa Maria-RS, no período de agosto a novembro de 1999. O delineamento experimental foi um fatorial 5x2 em blocos casualizados, com três repetições. Avaliaram-se cinco formas de reposição de nutrientes na solução nutritiva com base na condutividade elétrica (CE, no sistema de fluxo laminar de nutrientes - NFT, e duas cultivares de alface: Regina e Deisy, cultivadas em bancadas de produção formadas por telhas de fibro-cimento revestidas com tinta betuminosa Neutrolâ. Os resultados demonstraram que a reposição de nutrientes na solução nutritiva renovada a cada cultivo não resulta em ganhos de produtividade da alface em relação à ausência de reposição de nutrientes. Os métodos de reposição de nutrientes com base na redução de 0,25mScm-1 da CE inicial e redução de 50% da CE inicial permitiram a utilização da mesma solução por três cultivos consecutivos, sendo que a reposição com base na redução de 50% da CE inicial promoveu melhores resultados, em especial quanto à matéria fresca de planta. Não houve interação de cultivares com métodos de reposição, sendo a cultivar Regina caracterizada pelo maior número de folhas por planta.The objectives of this work were to compare lettuce yield under different nutrient replacement methods. The experiment was carried out in a plastic greenhouse of the "Universidade Federal de Santa Maria", RS, Brazil, from August to November, 1999. The experimental design was a factorial 5x2 in random blocks with three repetitions. Five kinds of nutrient replacement were evaluated based on electrical conductivity (EC in the

  12. [Dried nutrient media for the cultivation of pneumococcus and meningococcus].

    Science.gov (United States)

    Omarova, S M; Basnak'ian, I A; Artem'eva, T A

    1999-01-01

    Dried synthetic nutrient medium for the cultivation of meningococci and the accumulation of their biomass has been developed. The kinetics of the culture growth, changes in pH and in the content of dissolved oxygen in the medium during prolonged controlled processes of the cultivation of meningococci in a bioreactor with the use of this medium have been studied. The stable physico-chemical properties and composition of the polysaccharide-protein complex isolated from the biomass of meningococci grown in the above-mentioned medium have made it possible to use it for the preparation of the samples of group B meningococcal vaccine. In addition, dried semi-synthetic nutrient medium for the accumulation of pneumococci without the necessity of introducing blood or serum into the medium has been developed. As regards its biological properties, this newly developed medium make it not inferior to meat media, containing blood or serum, and ensures good yield of biomass.

  13. Fumaric and sorbic acid as additives in broiler feed.

    Science.gov (United States)

    Pirgozliev, V; Murphy, T C; Owens, B; George, J; McCann, M E E

    2008-06-01

    The aim of the experiment was to study the effect of dietary organic acids, fumaric and sorbic, on nitrogen corrected apparent metabolisable energy (AME(N)), metabolisability of nutrients, endogenous losses and performance on young broiler chickens. A total of 56 male Ross broilers were used in a growing experiment from 14 to 30d age. Seven experimental wheat-based (655g/kg) diets were formulated. The control diet did not contain organic acids. The other six diets were produced with the addition of fumaric or sorbic acids, replacing 0.5% , 1.0% or 1.5% of the wheat. The organic acid supplemented diets contained higher levels of AME(N) compared to the control diet. Overall, birds offered organic acids had lower feed intake. Dietary organic acids did not significantly affect weight gain or feed efficiency, however, birds offered supplemented diets had lower numbers of Lactic acid bacteria and Coliforms in the ileum and caeca. Birds offered organic acids had lower levels of endogenous losses compared to control fed birds. There was a negative relationship between AME(N) of the diets and excreted endogenous losses, measured as sialic acid. It can be concluded that the decrease in secretions from the gastrointestinal tract in the presence of fumaric and sorbic acids may be a mechanism involved in the mode of action of dietary organic acids.

  14. Soil microbial responses to nitrogen addition in arid ecosystems

    Directory of Open Access Journals (Sweden)

    Robert L Sinsabaugh

    2015-08-01

    Full Text Available The N cycle of arid ecosystems is influenced by low soil organic matter, high soil pH and extremes in water potential and temperature that lead to open canopies and development of biological soil crusts (biocrusts. We investigated the effects of N amendment on soil microbial dynamics in a Larrea tridentata-Ambrosia dumosa shrubland site in southern Nevada USA. Sites were fertilized with a NO3-NH4 mix at 0, 7, and 15 kg ha-1 yr-1 from March 2012 to March 2013. In March 2013, biocrust (0-0.5 cm and bulk soils (0-10 cm were collected beneath Ambrosia canopies and in the interspaces between plants. Biomass responses were assessed as bacterial and fungal SSU rRNA gene copy number and chlorophyll a concentration. Metabolic responses were measured by five ecoenzyme activities (EEA and rates of N transformation. By most measures, nutrient availability, microbial biomass and process rates were greater in soils beneath the shrub canopy compared to the interspace between plants, and greater in the surface biocrust horizon compared to the deeper 10 cm soil profile. Most measures responded positively to experimental N addition. Effect sizes were generally greater for bulk soil than biocrust. Results were incorporated into a meta-analysis of arid ecosystem responses to N.

  15. CO₂ alters community composition and response to nutrient enrichment of freshwater phytoplankton.

    Science.gov (United States)

    Low-Décarie, Etienne; Bell, Graham; Fussmann, Gregor F

    2015-03-01

    Nutrients can limit the productivity of ecosystems and control the composition of the communities of organisms that inhabit them. Humans are causing atmospheric CO2 concentrations to reach levels higher than those of the past millions of years while at the same time propagating eutrophication through the addition of nutrients to lakes and rivers. We studied the effect of elevated CO2 concentrations, nutrient addition and their interaction in a series of freshwater mesocosm experiments using a factorial design. Our results highlight the important role of CO2 in shaping phytoplankton communities and their response to nutrient addition. We found that CO2 greatly magnified the increase in phytoplankton growth caused by the increased availability of nutrients. Elevated CO2 also caused changes in phytoplankton community composition. As predicted from physiology and laboratory experiments, the taxonomic group that was most limited by current day CO2 concentrations, chlorophytes, increased in relative frequency at elevated CO2. This predictable change in community composition with changes in CO2 is not altered by changes in the availability of other nutrients.

  16. Generalized Nutrient Taxes Can Increase Consumer Welfare.

    Science.gov (United States)

    Bishai, David

    2015-11-01

    Certain nutrients can stimulate appetite making them fattening in a way that is not fully conveyed by the calorie content on the label. For rational eaters, this information gap could be corrected by more labeling. As an alternative, this paper proposes a set of positive and negative taxes on the fattening and slimming nutrients in food rather than on the food itself. There are conditions under which this tax plus subsidy system could increase welfare by stopping unwanted weight gain while leaving the final retail price of food unchanged. A nutrient tax system could improve welfare if fattening nutrients, net of their effect on weight, are inferior goods and the fiscal cost of administering the tax is sufficiently low. More data on the price elasticity of demand for nutrients as well as data on how specific nutrients affect satiety and how total calorie intake would be necessary before one could be sure a nutrient tax would work in practice. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Polylactides in additive biomanufacturing.

    Science.gov (United States)

    Poh, Patrina S P; Chhaya, Mohit P; Wunner, Felix M; De-Juan-Pardo, Elena M; Schilling, Arndt F; Schantz, Jan-Thorsten; van Griensven, Martijn; Hutmacher, Dietmar W

    2016-12-15

    New advanced manufacturing technologies under the alias of additive biomanufacturing allow the design and fabrication of a range of products from pre-operative models, cutting guides and medical devices to scaffolds. The process of printing in 3 dimensions of cells, extracellular matrix (ECM) and biomaterials (bioinks, powders, etc.) to generate in vitro and/or in vivo tissue analogue structures has been termed bioprinting. To further advance in additive biomanufacturing, there are many aspects that we can learn from the wider additive manufacturing (AM) industry, which have progressed tremendously since its introduction into the manufacturing sector. First, this review gives an overview of additive manufacturing and both industry and academia efforts in addressing specific challenges in the AM technologies to drive toward AM-enabled industrial revolution. After which, considerations of poly(lactides) as a biomaterial in additive biomanufacturing are discussed. Challenges in wider additive biomanufacturing field are discussed in terms of (a) biomaterials; (b) computer-aided design, engineering and manufacturing; (c) AM and additive biomanufacturing printers hardware; and (d) system integration. Finally, the outlook for additive biomanufacturing was discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Absorção de nutrientes pela planta de amendoim em cultura de primavera Nutrient uptake by peanut plants

    Directory of Open Access Journals (Sweden)

    Fernando A. Soares Coelho

    1967-01-01

    Full Text Available É apresentado estudo relativo à acumulação de matéria sêca, concentração e absorção de nutrientes em plantas de amendoim, em latossolo vermelho escuro, adubado e sem adubação. Em amostras de plantas colhidas semanalmente foram determinados os elementos: N, P, K, Ca, Mg e S. A adubação trouxe aumento de 85% no pêso sêco dos frutos e 53% no da planta. Com exceção do cálcio e do magnésio, os teores dos demais elementos foram mais elevados nas plantas adubadas. Cêrca de 80% do total de matéria sêca e de nutrientes nas plantas adubadas foram acumulados no período entre início da frutificação e início da maturação dos frutos. Nas plantas não adubadas essa acumulação representa cêrca de 60%. Êsses resultados evidenciam o período em que as plantas devem encontrar maior disponibilidade de nutrientes no solo.The dry matter accumulation and absorption as well as the accumulation of nitrogen, phosphorus, potassium, calcium, magnesium and sulfur by peanut in several growth stages under field conditions during the rainy season were investigated. The experiment was conducted at the Experimental Station "Theodureto de Camargo", in Campinas, where the soil is "dark red latosol". The seed variety used was "Tatu", and treatments comprised plots with and without fertilizer. The fertilizer treatment included micronutrients. The cultivation and insect and fungi control were those customary in large plantations. Plant sampling started 15 days after the emergence of the plants,, and from then on, once every week, until cropping time. For analytical purposes, the samples were divided into root, stem, leaf, and the fruit into shell and seed. The results showed definite patterns of accumulation of nutrients in the plant, as follows: nitrogen and phosphorus in the seed, sulfur in the root and potassium, calcium and magnesium in the stem and foliage. From the supplied elements, nitrogen, potassium and calcium were the most absorbed. The

  19. Cultivation of Leishmania sp. in nutrient broth.

    Science.gov (United States)

    Ozbilgin, A; Ozbel, Y; Alkan, M Z; Atambay, M; Ozcel, M A

    1995-08-01

    Bone-marrow aspiration and biopsy material samples obtained from two patients, one diagnosed as visceral and other as cutaneous leishmaniasis, were inoculated in Novy, McNeal, Nicolle (NNN) medium and nutrient broth (NB), containing fetal calf serum (FCS), penicillin and streptomycine. Both media were incubated at 27 degrees C for 10 days and observed daily for L. infantum and L. major promastigotes. Promastigotes were observed in nutrient broth after the first day, while in NNN media after the second or third day of incubation, indicating the effectiveness of nutrient broth in early diagnosis of both forms of leishmaniasis.

  20. Nutrient profiling of foods: creating a nutrient-rich food index.

    Science.gov (United States)

    Drewnowski, Adam; Fulgoni, Victor

    2008-01-01

    Nutrient profiling of foods, described as the science of ranking foods based on their nutrient content, is fast becoming the basis for regulating nutrition labels, health claims, and marketing and advertising to children. A number of nutrient profile models have now been developed by research scientists, regulatory agencies, and by the food industry. Whereas some of these models have focused on nutrients to limit, others have emphasized nutrients known to be beneficial to health, or some combination of both. Although nutrient profile models are often tailored to specific goals, the development process ought to follow the same science-driven rules. These include the selection of index nutrients and reference amounts, the development of an appropriate algorithm for calculating nutrient density, and the validation of the chosen nutrient profile model against healthy diets. It is extremely important that nutrient profiles be validated rather than merely compared to prevailing public opinion. Regulatory agencies should act only when they are satisfied that the scientific process has been followed, that the algorithms are transparent, and that the profile model has been validated with respect to objective measures of a healthy diet.