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Sample records for residues microbial numbers

  1. Impact of diverse soil microbial communities on crop residues decomposition

    Science.gov (United States)

    Mrad, Fida; Bennegadi-Laurent, Nadia; Ailhas, Jérôme; Leblanc, Nathalie; Trinsoutrot-Gattin, Isabelle; Laval, Karine; Gattin, Richard

    2017-04-01

    Soils provide many basic ecosystem services for our society and most of these services are carried out by the soil communities, thus influencing soils quality. Soil organic matter (SOM) can be considered as one of the most important soil quality indices for it plays a determinant role in many physical, chemical and biological processes, such as soil structure and erosion resistance, cation exchange capacity, nutrient cycling and biological activity (Andrews et al., 2004). Since a long time, exogenous organic inputs are largely used for improving agricultural soils, affecting highly soil fertility and productivity. The use of organic amendments such as crop residues influences the soil microbial populations' diversity and abundance. In the meantime, soil microbial communities play a major role in the organic matter degradation, and the effect of different microbial communities on the decomposition of crop residues is not well documented. In this context, studying the impact of crop residues on soil microbial ecology and the processes controlling the fate of plant residues in different management practices is essential for understanding the long-term environmental and agronomic effects on soil and organic matters. Our purpose in the present work was to investigate the decomposition by two contrasting microbial communities of three crop residues, and compare the effect of different residues amendments on the abundance and function of each soil microbial communities. Among the main crops which produce large amounts of residues, we focused on three different plants: wheat (Triticum aestivum L.), rape (Brassica napus) and sunflower (Helianthus annuus). The residues degradation in two soils of different management practices and the microbial activity were evaluated by: microbial abundance (microbial carbon, culturable bacteria, total DNA, qPCR), in combination with functional indicators (enzymatic assays and Biolog substrate utilization), kinetics of C and N

  2. Residue number systems theory and applications

    CERN Document Server

    Mohan, P V Ananda

    2016-01-01

    This new and expanded monograph improves upon Mohan's earlier book, Residue Number Systems (Springer, 2002) with a state of the art treatment of the subject. Replete with detailed illustrations and helpful examples, this book covers a host of cutting edge topics such as the core function, the quotient function, new Chinese Remainder theorems, and large integer operations. It also features many significant applications to practical communication systems and cryptography such as FIR filters and elliptic curve cryptography. Starting with a comprehensive introduction to the basics and leading up to current research trends that are not yet widely distributed in other publications, this book will be of interest to both researchers and students alike.

  3. FPGA Implementation of Uniform Random Number based on Residue Method

    Directory of Open Access Journals (Sweden)

    Zulfikar .

    2014-04-01

    Full Text Available This paper presents the implementation and comparisons of uniform random number on Field Programable Gate Array (FPGA. Uniform random numbers are generated based on residue method. The circuit of generating uniform random number is presented in general view. The circuit is constructed from a multiplexer, a multiplier, buffers and some basic gates. FPGA implementation of the designed circuit has been done into various Xilinx chips. Simulation results are viewed clearly in the paper. Random numbers are generated based on different parameters. Comparisons upon occupied area and maximum frequency from different Xilinx chip are examined. Virtex 7 is the fastest chip and Virtex 4 is the best choice in terms of occupied area. Finally, Uniform random numbers have been generated successfully on FPGA using residue method.Keywords: FPGA implementation, random number, uniform random number, residue method, Xilinx chips

  4. 40 CFR 158.2172 - Experimental use permit microbial pesticides residue data requirements table.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Experimental use permit microbial....2172 Experimental use permit microbial pesticides residue data requirements table. (a) General. Sections 158.100 through 158.130 describe how to use this table to determine the residue chemistry data...

  5. In situ dynamics of microbial communities during decomposition of wheat, rape, and alfalfa residues.

    Science.gov (United States)

    Pascault, Noémie; Cécillon, Lauric; Mathieu, Olivier; Hénault, Catherine; Sarr, Amadou; Lévêque, Jean; Farcy, Pascal; Ranjard, Lionel; Maron, Pierre-Alain

    2010-11-01

    Microbial communities are of major importance in the decomposition of soil organic matter. However, the identities and dynamics of the populations involved are still poorly documented. We investigated, in an 11-month field experiment, how the initial biochemical quality of crop residues could lead to specific decomposition patterns, linking biochemical changes undergone by the crop residues to the respiration, biomass, and genetic structure of the soil microbial communities. Wheat, alfalfa, and rape residues were incorporated into the 0-15 cm layer of the soil of field plots by tilling. Biochemical changes in the residues occurring during degradation were assessed by near-infrared spectroscopy. Qualitative modifications in the genetic structure of the bacterial communities were determined by bacterial-automated ribosomal intergenic spacer analysis. Bacterial diversity in the three crop residues at early and late stages of decomposition process was further analyzed from a molecular inventory of the 16S rDNA. The decomposition of plant residues in croplands was shown to involve specific biochemical characteristics and microbial community dynamics which were clearly related to the quality of the organic inputs. Decay stage and seasonal shifts occurred by replacement of copiotrophic bacterial groups such as proteobacteria successful on younger residues with those successful on more extensively decayed material such as Actinobacteria. However, relative abundance of proteobacteria depended greatly on the composition of the residues, with a gradient observed from alfalfa to wheat, suggesting that this bacterial group may represent a good indicator of crop residues degradability and modifications during the decomposition process.

  6. [FTIR Spectroscopic Analysis of Humic-Like Substances Extracted from the Microbial Residues].

    Science.gov (United States)

    Wang, Shuai; Dou, Sen; Zhang, Xi; Cui, Yan-jie; Wang, Ting

    2015-12-01

    Drived by the soil microorganisms, the decomposition and transformation of cellulose plays an important role in the formation of humic substances. The techniques of infrared spectrum combining with element analysis were adopted to compare the structural differences of humic-like substances (HLA, humic-like acid; Hu, humin) extracted from the microbial residues formed in the liquid shake-flask culture (70 days), in which the single fungi (Trichoderma viride, Penicillium and Aspergillus niger) and mixed strains participated. The results showed that: (1) The combination of two techniques could clarify the molecu- lar structure of HLA extracted from the microbial residues, however, it remained to be further discussed in terms of analyzing the structures of Hu; (2) Trichoderma viride was beneficial to the condensation of HLA extracted from its microbial residue, but Penicillium was more favorable to the degradation of HLA. (3) The oxidative degradation of HLA fractions extracted the microbial residues was implemented by Penicillium and mixed strains. Both of the mixed strains and Aspergillus niger were helpful to transfer the inorganic N compounds from the culture media into the organic N components of HLA and Hu extracted from the microbial residues, simultaneously increase their amino C contents and then provide the indispensable N source for the humification process.

  7. Microbial population, chemical composition and silage fermentation of cassava residues.

    Science.gov (United States)

    Napasirth, Viengsakoun; Napasirth, Pattaya; Sulinthone, Tue; Phommachanh, Kham; Cai, Yimin

    2015-09-01

    In order to effectively use the cassava (Manihot esculenta Crantz) residues, including cassava leaves, peel and pulp for livestock diets, the chemical and microbiological composition, silage preparation and the effects of lactic acid bacteria (LAB) inoculants on silage fermentation of cassava residues were studied. These residues contained 10(4) to 10(5) LAB and yeasts, 10(3) to 10(4) coliform bacteria and 10(4) aerobic bacteria in colony forming units (cfu) on a fresh matter (FM) basis. The molds were consistently at or below the detectable level (10(2) cfu of FM) in three kinds of cassava residues. Dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) content of cassava residues were 17.50-30.95%, 1.30-16.41% and 25.40-52.90% on a DM basis, respectively. The silage treatments were designed as control silage without additive (CO) or with LAB inoculants Chikuso-1 (CH, Lactobacillus plantarum) and Snow Lacto (SN, Lactobacillus rhamnosus) at a rate of 5 mg/kg of FM basis. All silages were well preserved with a low pH (below 4.0) value and when cassava residues silage treated with inoculants CH and SN improved fermentation quality with a lower pH, butyric acid and higher lactic acid than control silage. © 2015 Japanese Society of Animal Science.

  8. Pesticide residues and microbial contamination of water resources in the MUDA rice agroecosystem

    International Nuclear Information System (INIS)

    Cheah Uan Boh; Lum Keng Yeang

    2002-01-01

    Studies on the water resources of the Muda rice growing areas revealed evidence of pesticide residues in the agroecosystem. While the cyclodiene endosulfan was found as a ubiquitous contaminant, the occurrence of other organochlorine insecticides was sporadic. The presence of 2,4-D, paraquat and molinate residues was also evident but the occurrence of these herbicides was seasonal. Residue levels of molinate were generally higher than those from the other herbicides. The problem of thiobencarb and carbofuran residues was not encountered. Analyses for microbial contamination revealed that the water resources were unfit for drinking; coliform counts were higher during certain periods of the year than others. (Author)

  9. Influence of organic waste and residue mud additions on chemical, physical and microbial properties of bauxite residue sand.

    Science.gov (United States)

    Jones, Benjamin E H; Haynes, Richard J; Phillips, Ian R

    2011-02-01

    In an alumina refinery, bauxite ore is treated with sodium hydroxide at high temperatures and pressures and for every tone of alumina produced, about 2 tones of alkaline, saline bauxite processing waste is also produced. At Alcoa, a dry stacking system of disposal is used, and it is the sand fraction of the processing waste that is rehabilitated. There is little information available regarding the most appropriate amendments to add to the processing sand to aid in revegetation. The purpose of this study was to investigate how the addition of organic wastes (biosolids and poultry manure), in the presence or absence of added residue mud, would affect the properties of the residue sand and its suitability for revegetation. Samples of freshly deposited residue sand were collected from Alcoa's Kwinana refinery. Samples were treated with phosphogypsum (2% v/v), incubated, and leached. A laboratory experiment was then set up in which the two organic wastes were applied at 0 or the equivalent to 60 tones ha(-1) in combination with residue mud added at rates of 0%, 10% and 20% v/v. Samples were incubated for 8 weeks, after which, key chemical, physical and microbial properties of the residue sand were measured along with seed germination. Additions of residue mud increased exchangeable Na(+), ESP and the pH, and HCO (3) (-) and Na(+) concentrations in saturation paste extracts. Additions of biosolids and poultry manure increased concentrations of extractable P, NH (4) (+) , K, Mg, Cu, Zn, Mn and Fe. Addition of residue mud, in combination with organic wastes, caused a marked decrease in macroporosity and a concomitant increase in mesoporosity, available water holding capacity and the quantity of water held at field capacity. With increasing residue mud additions, the percentage of sample present as sand particles (2 mm diameter) increased; greatest aggregation occurred where a combination of residue mud and poultry manure were added. Stability of aggregates, as measured by

  10. Evaluation of microbially enhanced composting of sophora flavescens residues.

    Science.gov (United States)

    Wang, Hai B; Han, Li R; Feng, Jun T; Zhang, Xing

    2016-02-01

    The effects of inoculants on the composting of Sophora flavescens residues were evaluated based on several physical, chemical and biological parameters, as well as the infrared spectra. Compared to the control compost without inoculants, the treatment compost with inoculants (Bacillus subtilis strain G-13 and Chaetomium thermophilum strain GF-1) had a significantly longer thermophilic duration, higher cellulase activity and a higher degradation rate of cellulose, hemicellulose and lignin (P compost with apparently lower C:N ratio (15.88 vs. 17.77) and NH 4 -N:NO 3 -N ratio (0.16 vs. 0.20) was obtained with the inoculation comparing with the control (P composting process and increase the maturity degree of compost as indicated by the germination index (GI) in which the treatment reached the highest GI of 133.2% at day 15 while the control achieved the highest GI of 125.7% at day 30 of the composting. Inoculation with B. subtilis and C. thermophilum is a useful method to enhance the S. flavescens residues composting according to this study.

  11. Generic GPCR residue numbers - aligning topology maps while minding the gaps

    DEFF Research Database (Denmark)

    Isberg, Vignir; de Graaf, Chris; Bortolato, Andrea

    2015-01-01

    structures for classes B, C, and F now call for a community consensus in residue numbering within and across these classes. Furthermore, the structural era has uncovered helix bulges and constrictions that offset the generic residue numbers. The use of generic residue numbers depends on convenient access...... by pharmacologists, chemists, and structural biologists. We review the generic residue numbering schemes for each GPCR class, as well as a complementary structure-based scheme, and provide illustrative examples and GPCR database (GPCRDB) web tools to number any receptor sequence or structure....

  12. Albendazole residues in goat's milk: Interferences in microbial inhibitor tests used to detect antibiotics in milk

    OpenAIRE

    Romero, Tamara; Althaus, Rafael; Moya, Vicente Javier; Beltrán, María del Carmen; Reybroeck, Wim; Molina, María Pilar

    2016-01-01

    Albendazole (ABZ) residues in goat's milk and their effect on the response of microbial inhibitor tests used for screening antibiotics were evaluated. A total of 18 Murciano-Granadina goats were treated with ABZ and individually milked once a day over a 7-day period. ABZ quantification was performed by high performance liquid chromatography. The ABZ parent drug was not detected. The maximum concentration of its metabolites (ABZ sulfoxide, ABZ sulfone, and ABZ 2-aminosulfone) was reached on th...

  13. Albendazole residues in goat's milk: Interferences in microbial inhibitor tests used to detect antibiotics in milk

    Directory of Open Access Journals (Sweden)

    Tamara Romero

    2017-04-01

    Full Text Available Albendazole (ABZ residues in goat's milk and their effect on the response of microbial inhibitor tests used for screening antibiotics were evaluated. A total of 18 Murciano-Granadina goats were treated with ABZ and individually milked once a day over a 7-day period. ABZ quantification was performed by high performance liquid chromatography. The ABZ parent drug was not detected. The maximum concentration of its metabolites (ABZ sulfoxide, ABZ sulfone, and ABZ 2-aminosulfone was reached on the 1st day post treatment (260.0 ± 70.1 μg/kg, 112.8 ± 28.7 μg/kg, 152.0 ± 23.6 μg/kg, respectively, decreasing to lower than the maximum residue limit (MRL, 100 μg/kg on the 3rd day post treatment. Milk samples were also analyzed by microbial tests [Brilliant Black Reduction Test (BRT MRL, Delvotest SP-NT MCS and Eclipse 100], and only one positive result was found for Delvotest SP-NT MCS and Eclipse 100. However, a high occurrence of positive outcomes was obtained for BRT MRL during 6 days post treatment, whereas ABZ residues were not detected from the 4th day post administration, suggesting that factors other than the antiparasitic agent might affect the microbial test response.

  14. Albendazole residues in goat's milk: Interferences in microbial inhibitor tests used to detect antibiotics in milk.

    Science.gov (United States)

    Romero, Tamara; Althaus, Rafael; Moya, Vicente Javier; Beltrán, María Del Carmen; Reybroeck, Wim; Molina, María Pilar

    2017-04-01

    Albendazole (ABZ) residues in goat's milk and their effect on the response of microbial inhibitor tests used for screening antibiotics were evaluated. A total of 18 Murciano-Granadina goats were treated with ABZ and individually milked once a day over a 7-day period. ABZ quantification was performed by high performance liquid chromatography. The ABZ parent drug was not detected. The maximum concentration of its metabolites (ABZ sulfoxide, ABZ sulfone, and ABZ 2-aminosulfone) was reached on the 1 st day post treatment (260.0 ± 70.1 μg/kg, 112.8 ± 28.7 μg/kg, 152.0 ± 23.6 μg/kg, respectively), decreasing to lower than the maximum residue limit (MRL, 100 μg/kg) on the 3 rd day post treatment. Milk samples were also analyzed by microbial tests [Brilliant Black Reduction Test (BRT) MRL, Delvotest SP-NT MCS and Eclipse 100], and only one positive result was found for Delvotest SP-NT MCS and Eclipse 100. However, a high occurrence of positive outcomes was obtained for BRT MRL during 6 days post treatment, whereas ABZ residues were not detected from the 4 th day post administration, suggesting that factors other than the antiparasitic agent might affect the microbial test response. Copyright © 2016. Published by Elsevier B.V.

  15. Stabilization of diverse microbial residues in California and Puerto Rico Forest Soils

    Science.gov (United States)

    Throckmorton, H.; Bird, J.; Dane, L.; Firestone, M.; Horwath, W.

    2012-04-01

    The contribution of C from the turnover of diverse microorganisms to stable C pools remains poorly understood. This study follows the turnover of 13C labeled nonliving residues from diverse microbial groups in situ in a temperate forest in California (CA) and a tropical forest in Puerto Rico (PR), during 5 sampling points per site- over a 3 and 2 year period, respectively. Microbial groups include fungi, actinomycetes, Gm(+) bacteria, and Gm(-) bacteria, isolated from CA and PR soils to obtain temperate and tropical isolates. Results indicated that, despite unique biochemical makeup among groups as determined by Py-GC-MS, microbial residues exhibited similar mean residence times (MRTs) within each site. A density fractionation approach isolated: a "light fraction" (LF), non-mineral aggregate "occluded fraction" (OF), and a "mineral bound fraction" (MF). Microbial C inputs were more stable in the OF and MF than the LF throughout the course of the study at both sites. There were no significant differences in 13C recovery among microbes in any PR fractions, despite minor differences in overall MRTs. In CA, there were some significant differences in 13C recovery among microbial inputs in the LF and OF, which related to 13C recoveries in whole soils. In the CA MF, microbial recoveries did not differ, and low variability among treatments was observed. Results support increased protection of microbial C via association with the mineral matrix; however, differential sorption of some microbial isolates over others was not observed. Overall results suggest that inherent recalcitrance of microbial residues may be more important to determining its stability in CA soils when it is 1) unassociated with the mineral matrix (LF); or 2) occluded within aggregates; compared with that strongly associated with mineral surfaces (MF). The overall composition of SOM in fractions also differed, with a greater concentration of benzene and N compounds in the MF; lignin and phenol compounds

  16. Cancellative Residuated Lattices Arising on 2-Generated Submonoids of Natural Numbers

    Czech Academy of Sciences Publication Activity Database

    Horčík, Rostislav

    2010-01-01

    Roč. 63, 2-3 (2010), s. 261-274 ISSN 0002-5240 R&D Projects: GA AV ČR KJB100300701 Institutional research plan: CEZ:AV0Z10300504 Keywords : residuated lattice * cancellative commutative residuated lattice * subvariety lattice * submonoid of natural numbers Subject RIV: BA - General Mathematics Impact factor: 0.479, year: 2010

  17. Constant-coefficient FIR filters based on residue number system arithmetic

    Directory of Open Access Journals (Sweden)

    Stamenković Negovan

    2012-01-01

    Full Text Available In this paper, the design of a Finite Impulse Response (FIR filter based on the residue number system (RNS is presented. We chose to implement it in the (RNS, because the RNS offers high speed and low power dissipation. This architecture is based on the single RNS multiplier-accumulator (MAC unit. The three moduli set {2n+1,2n,2n-1}, which avoids 2n+1 modulus, is used to design FIR filter. A numerical example illustrates the principles of residue encoding, residue arithmetic, and residue decoding for FIR filters.

  18. Estimation of the Number of Microbial Species Comprising a Population

    National Research Council Canada - National Science Library

    Slattery, Melanie R

    2008-01-01

    ... comprising a population. This research consisted of creating diverse populations, with a known number of species, and applying the aforementioned methods to samples drawn from the constructed populations...

  19. Microbial Physiology of the Conversion of Residual Oil to Methane: A Protein Prospective

    Science.gov (United States)

    Morris, Brandon E. L.; Bastida-Lopez, Felipe; von Bergen, Martin; Richnow, Hans-Hermann; Suflita, Joseph M.

    2010-05-01

    Traditional petroleum recovery techniques are unable to extract the majority of oil in most petroliferous deposits. The recovery of even a fraction of residual hydrocarbon in conventional reserves could represent a substantive energy supply. To this end, the microbial conversion of residual oil to methane has gained increasing relevance in recent years [1,2]. Worldwide demand for methane is expected to increase through 2030 [3], as it is a cleaner-burning alternative to traditional fuels [4]. To investigate the microbial physiology of hydrocarbon-decomposition and ultimate methanogenesis, we initiated a two-pronged approach. First, a model alkane-degrading sulfate-reducing bacterium, Desulfoglaeba alkanexedens, was used to interrogate the predominant metabolic pathway(s) differentially expressed during growth on either n-decane or butyrate. A total of 81 proteins were differentially expressed during bacterial growth on butyrate, while 100 proteins were unique to the alkane-grown condition. Proteins related to alkylsuccinate synthase, or the homologous 1-methyl alkylsuccinate synthase, were identified only in the presence of the hydrocarbon. Secondly, we used a newly developed stable isotope probing technique [5] targeted towards proteins to monitor the flux of carbon through a residual oil-degrading bacterial consortium enriched from a gas-condensate contaminated aquifer [1]. Combined carbon and hydrogen stable isotope fractionation identified acetoclastic methanogenesis as the dominant process in this system. Such findings agree with the previous clone library characterization of the consortium. Furthermore, hydrocarbon activation was determined to be the rate-limiting process during the net conversion of residual oil to methane. References 1. Gieg, L.M., K.E. Duncan, and J.M. Suflita, Bioenegy production via microbial conversion of residual oil to natural gas. Appl Environ Micro, 2008. 74(10): p. 3022-3029. 2. Jones, D.M., et al., Crude-oil biodegradation via

  20. Life cycle of soil sggregates: from root residue to microbial and physical hotspots

    Science.gov (United States)

    Ghezzehei, T. A.; Or, D.

    2017-12-01

    Soil aggregation is a physical state of soil in which clumps of primary soil particles are held together by biological and/or chemical cementing agents. Aggregations plays important role in storage and movement of water and essential gases, nutrient cycling, and ultimately supporting microbial and plant life. It is also one of the most dynamic and sensitive soil qualities, which readily responds to disturbances such as cultivation, fire, drought, flooding, and changes in vegetation. Soil aggregation that is primarily controlled by organic matter generally exhibits hierarchical organization of soil constituents into stable units that range in size from a few microns to centimeters. However, this conceptual model of soil aggregation as the key unifying mechanism remains poorly quantified and is rarely included in predictive soil models. Here we provide a biophysical framework for quantitative and predictive modeling of soil aggregation and its attendant soil characteristics. The framework treats aggregates as hotspots of biological, chemical and physical processes centered around roots and root residue. We keep track of the life cycle of an individual aggregate from it genesis in the rhizosphere, fueled by rhizodeposition and mediated by vigorous microbial activity, until its disappearance when the root-derived resources are depleted. The framework synthesizes current understanding of microbial life in porous media; water holding and soil binding capacity of biopolymers; and environmental controls on soil organic matter dynamics. The framework paves a way for integration of processes that are presently modeled as disparate or poorly coupled processes, including storage and protection of carbon, microbial activity, greenhouse gas fluxes, movement and storage of water, resistance of soils against erosion.

  1. Microbial response to salinity stress in a tropical sandy soil amended with native shrub residues or inorganic fertilizer.

    Science.gov (United States)

    Sall, Saïdou Nourou; Ndour, Ndèye Yacine Badiane; Diédhiou-Sall, Siré; Dick, Richard; Chotte, Jean-Luc

    2015-09-15

    Soil degradation and salinization caused by inappropriate cultivation practices and high levels of saltwater intrusion are having an adverse effect on agriculture in Central Senegal. The residues of Piliostigma reticulatum, a local shrub that coexists with crops, were recently shown to increase particulate organic matter and improve soil quality and may be a promising means of alleviating the effects of salinization. This study compared the effects of inorganic fertilizer and P. reticulatum residues on microbial properties and the ability of soil to withstand salinity stress. We hypothesized that soils amended with P. reticulatum would be less affected by salinity stress than soils amended with inorganic fertilizer and control soil. Salinity stress was applied to soil from a field site that had been cultivated for 5 years under a millet/peanut crop rotation when microbial biomass, phospholipid fatty acid (PLFA) community profile, catabolic diversity, microbial activities were determined. Microbial biomass, nitrification potential and dehydrogenase activity were higher by 20%, 56% and 69% respectively in soil with the organic amendment. With salinity stress, the structure and activities of the microbial community were significantly affected. Although the biomass of actinobacteria community increased with salinity stress, there was a substantial reduction in microbial activity in all soils. The soil organically amended was, however, less affected by salinity stress than the control or inorganic fertilizer treatment. This suggests that amendment using P. reticulatum residues may improve the ability of soils to respond to saline conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. The effects of toothpastes on the residual microbial contamination of toothbrushes.

    Science.gov (United States)

    Warren, D P; Goldschmidt, M C; Thompson, M B; Adler-Storthz, K; Keene, H J

    2001-09-01

    Contaminated toothbrushes have been shown to harbor and transmit viruses and bacteria. The authors conducted a study to evaluate the effect of a triclosan-containing toothpaste on the residual anaerobic microbial contamination of toothbrushes. Twenty patients who had Type III or Type IV periodontitis participated in this study. One side of each of their mouths served as a control (no toothpaste). The teeth on the other side were brushed with a regular toothpaste or a triclosan-containing toothpaste. After the toothbrushes were allowed to dry in air for four hours, the authors placed the toothbrush heads in solution, dislodged the microbes from the brushes by vortexing and plated them in culture dishes. The authors anerobically incubated the culture dishes and determined the presence or absence of Prevotella species or Ps; Porphyromonas gingivalis, or Pg; and Actinobacillus actinomycetemcomitans, or Aa. The authors detected Aa and Pg on the control toothbrushes more frequently than they did Ps. This variation in isolation frequency was statistically significant by chi 2 analysis (P frequency of the three test organisms between the control and regular-toothpaste groups, between the control and triclosan-containing--toothpaste groups, and between the triclosan-containing--toothpaste and regular-toothpaste groups. They found no significant intergroup differences in the isolation frequencies after using chi 2 analysis. Toothpaste use reduced the residual microbial contamination for two of three test organisms, but the lower isolation frequencies were not statistically significant. Further study in this area is indicated. Dental professionals should advise patients who have systemic, localized or oral inflammatory diseases to disinfect or frequently replace their toothbrushes.

  3. Microbial diversity of a Mediterranean soil and its changes after biotransformed dry olive residue amendment.

    Directory of Open Access Journals (Sweden)

    José A Siles

    Full Text Available The Mediterranean basin has been identified as a biodiversity hotspot, about whose soil microbial diversity little is known. Intensive land use and aggressive management practices are degrading the soil, with a consequent loss of fertility. The use of organic amendments such as dry olive residue (DOR, a waste produced by a two-phase olive-oil extraction system, has been proposed as an effective way to improve soil properties. However, before its application to soil, DOR needs a pre-treatment, such as by a ligninolytic fungal transformation, e.g. Coriolopsis floccosa. The present study aimed to describe the bacterial and fungal diversity in a Mediterranean soil and to assess the impact of raw DOR (DOR and C. floccosa-transformed DOR (CORDOR on function and phylogeny of soil microbial communities after 0, 30 and 60 days. Pyrosequencing of the 16S rRNA gene demonstrated that bacterial diversity was dominated by the phyla Proteobacteria, Acidobacteria, and Actinobacteria, while 28S-rRNA gene data revealed that Ascomycota and Basidiomycota accounted for the majority of phyla in the fungal community. A Biolog EcoPlate experiment showed that DOR and CORDOR amendments decreased functional diversity and altered microbial functional structures. These changes in soil functionality occurred in parallel with those in phylogenetic bacterial and fungal community structures. Some bacterial and fungal groups increased while others decreased depending on the relative abundance of beneficial and toxic substances incorporated with each amendment. In general, DOR was observed to be more disruptive than CORDOR.

  4. Residual organic matter and microbial respiration in bottom ash: Effects on metal leaching and eco-toxicity.

    Science.gov (United States)

    Ilyas, A; Persson, K M; Persson, M

    2015-09-01

    A common assumption regarding the residual organic matter, in bottom ash, is that it does not represent a significant pool of organic carbon and, beyond metal-ion complexation process, it is of little consequence to evolution of ash/leachate chemistry. This article evaluates the effect of residual organic matter and associated microbial respiratory processes on leaching of toxic metals (i.e. arsenic, copper, chromium, molybdenum, nickel, lead, antimony and zinc), eco-toxicity of ash leachates. Microbial respiration was quantified with help of a respirometric test equipment OXITOP control system. The effect of microbial respiration on metal/residual organic matter leaching and eco-toxicity was quantified with the help of batch leaching tests and an eco-toxicity assay - Daphnia magna. In general, the microbial respiration process decreased the leachate pH and eco-toxicity, indicating modification of bioavailability of metal species. Furthermore, the leaching of critical metals, such as copper and chromium, decreased after the respiration in both ash types (fresh and weathered). It was concluded that microbial respiration, if harnessed properly, could enhance the stability of fresh bottom ash and may promote its reuse. © The Author(s) 2015.

  5. Recycling organic residues in agriculture impacts soil-borne microbial community structure, function and N2O emissions.

    NARCIS (Netherlands)

    Suleiman, A.K.A.; Lourenço, Késia S.; Pitombo, L.; Mendes, Lukas W.; Roesch, L.F.W.; Pijl, A.S.; do Carmo, J.B.; Cantarella, Heitor; Kuramae, E.E.

    2018-01-01

    Recycling residues is a sustainable alternative to improve soil structure and increase the stock of nutrients. However, information about the magnitude and duration of disturbances caused by crop and industrial wastes on soil microbial community structure and function is still scarce. The objective

  6. The good, the bad or the ugly: Microbial biomass of biogas residues as a contributor to soil carbon cycle

    Science.gov (United States)

    Coban, H.; Miltner, A.; Kaestner, M.

    2013-12-01

    Loss of soil organic matter is a recent problem in soils all over the world. This can be related to enhanced mineralization of the soil organic matter due to land use change, which is a source of anthropogenic carbon dioxide increase. For example, the carbon input from plant residues is reduced because of the increased cultivation of bioenergy crops. In order to avoid soil degradation, application of biogas residues is a common practice in such areas. Biogas residues are side products of biogas production and contain microbial biomass. Application of these residues as soil additive influences the soil microorganisms as well as the carbon cycle. We study this effect by incubating 13C-labeled biogas residues in an arable soil from the Static Fertilization Experiment in Bad Lauchstaedt, Germany. Labeled residues were produced via labeling of active microbial biomass by addition of KH13CO3 to biogas reactors. High enrichment in the various phospholipid fatty acids proved the successful labeling of the biomass. The labeled biogas residues are being long-term incubated in the soil. During incubation, we monitor the fate of the carbon by analyzing the label in phospholipid fatty acids, amino acids as well as carbon dioxide. This allows us to trace the fate of the biogas residues-derived C in soil and to quantify the effect on the transformation of the natural soil organic matter (e.g. negative effects such as priming effects). Also, microbial community dynamics will be determined using molecular biology tools such as denaturing gradient gel electrophoresis (DGGE) and real-time quantitative PCR (Q-PCR). In order to prevent potentially negative effects, various additives such as charred biomaterials, clays and chopped bark will be tested to improve the carbon storage in soil. In conclusion, this study investigates the fate and impact of biogas residues used as a soil additive on the soil microbial community and amount of soil organic matter. It is aimed to understand and

  7. [Construction of a microbial consortium RXS with high degradation ability for cassava residues and studies on its fermentative characteristics].

    Science.gov (United States)

    He, Jiang; Mao, Zhong-Gui; Zhang, Qing-Hua; Zhang, Jian-Hua; Tang, Lei; Zhang, Hong-Jian

    2012-03-01

    A microbial consortium with high effective and stable cellulosic degradation ability was constructed by successive enrichment and incubation in a peptone cellulose medium using cassava residues and filter paper as carbon sources, where the inoculums were sampled from the environment filled with rotten lignocellulosic materials. The degradation ability to different cellulosic materials and change of main parameters during the degradation process of cassava residues by this consortium was investigated in this study. It was found that, this consortium can efficiently degrade filter paper, absorbent cotton, avicael, wheat-straw and cassava residues. During the degradation process of cassava residues, the key hydrolytic enzymes including cellulase, hemicellulase and pectinase showed a maximum enzyme activity of 34.4, 90.5 and 15.8 U on the second or third day, respectively. After 10 days' fermentation, the degradation ratio of cellulose, hemicellulose and lignin of cassava residues was 79.8%, 85.9% and 19.4% respectively, meanwhile the loss ratio of cassava residues reached 61.5%. Otherwise,it was found that the dominant metabolites are acetic acid, butyric acid, caproic acid and glycerol, and the highest hydrolysis ratio is obtained on the second day by monitoring SCOD, total volatile fatty acids and total sugars. The above results revealed that this consortium can effectively hydrolyze cassava residues (the waste produced during the cassava based bioethanol production) and has great potential to be utilized for the pretreatment of cassava residues for biogas fermentation.

  8. Bidet toilet seats with warm-water tanks: residual chlorine, microbial community, and structural analyses.

    Science.gov (United States)

    Iyo, Toru; Asakura, Keiko; Nakano, Makiko; Yamada, Mutsuko; Omae, Kazuyuki

    2016-02-01

    Despite the reported health-related advantages of the use of warm water in bidets, there are health-related disadvantages associated with the use of these toilet seats, and the bacterial research is sparse. We conducted a survey on the hygienic conditions of 127 warm-water bidet toilet seats in restrooms on a university campus. The spray water from the toilet seats had less residual chlorine than their tap water sources. However, the total viable microbial count was below the water-quality standard for tap water. In addition, the heat of the toilet seats' warm-water tanks caused heterotrophic bacteria in the source tap water to proliferate inside the nozzle pipes and the warm-water tanks. Escherichia coli was detected on the spray nozzles of about 5% of the toilet seats, indicating that the self-cleaning mechanism of the spray nozzles was largely functioning properly. However, Pseudomonas aeruginosa was detected on about 2% of the toilet seats. P. aeruginosa was found to remain for long durations in biofilms that formed inside warm-water tanks. Infection-prevention measures aimed at P. aeruginosa should receive full consideration when managing warm-water bidet toilet seats in hospitals in order to prevent opportunistic infections in intensive care units, hematology wards, and other hospital locations.

  9. Thermophilic Dry Methane Fermentation of Distillation Residue Eluted from Ethanol Fermentation of Kitchen Waste and Dynamics of Microbial Communities.

    Science.gov (United States)

    Huang, Yu-Lian; Tan, Li; Wang, Ting-Ting; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji

    2017-01-01

    Thermophilic dry methane fermentation is advantageous for feedstock with high solid content. Distillation residue with 65.1 % moisture content was eluted from ethanol fermentation of kitchen waste and subjected to thermophilic dry methane fermentation, after adjusting the moisture content to 75 %. The effect of carbon to nitrogen (C/N) ratio on thermophilic dry methane fermentation was investigated. Results showed that thermophilic dry methane fermentation could not be stably performed for >10 weeks at a C/N ratio of 12.6 and a volatile total solid (VTS) loading rate of 1 g/kg sludge/d; however, it was stably performed at a C/N ratio of 19.8 and a VTS loading rate of 3 g/kg sludge/d with 83.4 % energy recovery efficiency. Quantitative PCR analysis revealed that the number of bacteria and archaea decreased by two orders of magnitude at a C/N ratio of 12.6, whereas they were not influenced at a C/N ratio of 19.8. Microbial community analysis revealed that the relative abundance of protein-degrading bacteria increased and that of organic acid-oxidizing bacteria and acetic acid-oxidizing bacteria decreased at a C/N ratio of 12.6. Therefore, there was accumulation of NH 4 + and acetic acid, which inhibited thermophilic dry methane fermentation.

  10. High quality residues from cover crops favor changes in microbial community and enhance C and N sequestration

    Directory of Open Access Journals (Sweden)

    Ileana Frasier

    2016-04-01

    Full Text Available The objective of the study was to evaluate the effect of a change in management on the soil microbial community and C sequestration. We conducted a 3-year field study in La Pampa (Argentina with rotation of sorghum (Sorghum bicolor in zero tillage alternating with rye (Secale cereale and vetch (Vicia villosa ssp. dasycarpa. Soil was sampled once a year at two depths. Soil organic matter fractions, dissolved organic matter, microbial biomass (MBC and community composition (DNA extraction, qPCR, and phospholipid FAME profiles were determined. Litter, aerial- and root biomass were collected and all material was analyzed for C and N. Results showed a rapid response of microbial biomass to a bacterial dominance independent of residue quality. Vetch had the highest diversity index, while the fertilized treatment had the lowest one. Vetch–sorghum rotation with high N mineralization rates and diverse microbial community sequestered more C and N in stable soil organic matter fractions than no-till sorghum alone or with rye, which had lower N turnover rates. These results reaffirm the importance of enhanced soil biodiversity for maintaining soil ecosystem functioning and services. The supply of high amounts of N-rich residues as provided by grass–legume cover crops could fulfill this objective.

  11. Low-power implementation of polyphase filters in Quadratic Residue Number System

    DEFF Research Database (Denmark)

    Cardarilli, Gian Carlo; Re, Andrea Del; Nannarelli, Alberto

    2004-01-01

    The aim of this work is the reduction of the power dissipated in digital filters, while maintaining the timing unchanged. A polyphase filter bank in the Quadratic Residue Number System (QRNS) has been implemented and then compared, in terms of performance, area, and power dissipation...... to the implementation of a polyphase filter bank in the traditional two's complement system (TCS). The resulting implementations, designed to have the same clock rates, show that the QRNS filter is smaller and consumes less power than the TCS one....

  12. Microbial growth yield estimates from thermodynamics and its importance for degradation of pesticides and formation of biogenic non-extractable residues

    DEFF Research Database (Denmark)

    Brock, Andreas Libonati; Kästner, M.; Trapp, Stefan

    2017-01-01

    In biodegradation studies with isotope-labelled pesticides, fractions of non-extractable residues (NER) remain, but their nature and composition is rarely known, leading to uncertainty about their risk. Microbial growth leads to incorporation of carbon into the microbial mass, resulting in biogen...

  13. pH and Organic Carbon Dose Rates Control Microbially Driven Bioremediation Efficacy in Alkaline Bauxite Residue.

    Science.gov (United States)

    Santini, Talitha C; Malcolm, Laura I; Tyson, Gene W; Warren, Lesley A

    2016-10-18

    Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H + produced per day with pH decreasing from 9.5 to ≤6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.

  14. Bio-electrospraying and droplet-based microfluidics: control of cell numbers within living residues

    Energy Technology Data Exchange (ETDEWEB)

    Hong Jongin; DeMello, Andrew J [Nanostructured Materials and Devices Group, Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Jayasinghe, Suwan N, E-mail: a.demello@imperial.ac.u, E-mail: s.jayasinghe@ucl.ac.u [BioPhysics Group, Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom)

    2010-04-15

    Bio-electrospraying (BES) has demonstrated great promise as a rapidly evolving strategy for tissue engineering and regenerative biology/medicine. Since its discovery in 2005, many studies have confirmed that cells (immortalized, primary and stem cells) and whole organisms (Danio rerio, Xenopus tropicalis, Caenorhabditis elegans to Drosophila) remain viable post-bio-electrospraying. Although this bio-protocol has achieved much, it suffers from one crucial problem, namely the ability to precisely control the number of cells within droplets and or encapsulations. If overcome, BES has the potential to become a high-efficiency biotechnique for controlled cell encapsulation, a technique most useful for a wide range of applications in biology and medicine ranging from the forming of three-dimensional cultures to an approach for treating diseases such as type I diabetes. In this communication, we address this issue by demonstrating the coupling of BES with droplet-based microfluidics for controlling live cell numbers within droplets and residues. (communication)

  15. Dynamic changes in functional gene copy numbers and microbial communities during degradation of pyrene in soils

    International Nuclear Information System (INIS)

    Peng Jingjing; Cai Chao; Qiao Min; Li Hong; Zhu Yongguan

    2010-01-01

    This study investigates the dynamics of pyrene degradation rates, microbial communities, and functional gene copy numbers during the incubation of pyrene-spiked soils. Spiking pyrene to the soil was found to have negligible effects on the bacterial community present. Our results demonstrated that there was a significant difference in nidA gene copy numbers between sampling dates in QZ soil. Mycobacterium 16S rDNA clone libraries showed that more than 90% mycobacteria detected were closely related to fast-growing PAH-degrading Mycobacterium in pyrene-spiked soil, while other sequences related to slow-growing Mycobacterium were only detected in the control soil. It is suggested that nidA gene copy number and fast-growing PAH-degrading Mycobacterium could be used as indicators to predict pyrene contamination and its degradation activity in soils. - nidA gene and fast-growing PAH-degrading Mycobacterium can serve as indicators for pyrene contamination.

  16. Effect of soil-bound residues of malathion on microbial activities

    International Nuclear Information System (INIS)

    Hussain, A.; Iqbal, Z.; Asi, M.R.; Tahira, R.; Chudhary, J.A.

    2001-01-01

    The effect of soil-bound residues of malathion on CO/sub 2/ evolution, dehydrogenase activity and some nitrogen transformations in a loam soil was investigated under laboratory conditions. The soil samples containing bound residues arising from 10 mg g-1 of the applied malathion were mixed in equal quantity with fresh soil and compared with solvent extracted control soil without bound residues (extracted in the same way as soil containing bound residues). Another control comprising un extracted fresh soil without bound residues was also kept to study the effect of solvent extraction on the biological activity. Rate of Carbon mineralization (CO/sub 2/ evolution) was decreased in the presence of soil-bound residues of malathion. Bound residues also affected dehydrogenase activity of soil. Over 40% inhibition of dehydrogenase activity was observed after 4 days and the inhibition persisted at least for 12 days. Nitrogen mineralization was stimulated in soil containing bound residues of malathion and this stimulatory effect increased with time of incubation. Nitrification was partially inhibited in the presence of soil-bound residues of malathion. The inhibitory effect of the soil-bound residues on nitrification did not show much variation with time. The soil-bound residues did not affect denitrification rate (N/sub 2/O evolution). Nitrogen fixation (acetylene reduction) was partially inhibited in soil amended with bound residues of malathion and the inhibitory effect persisted for at least one week. In general, soil bound residues of malathion inhibited CO/sub 2/ evolution, dehydrogenase activity, nitrification and nitrogen fixation while mineralization of nitrogen was stimulated. Denitrification was not affected by the applied insecticide. (author)

  17. Microbial Biomass Changes during Decomposition of Plant Residues in a Lixisol

    Directory of Open Access Journals (Sweden)

    Kachaka, SK.

    2003-01-01

    Full Text Available A lixisol was amended with four different alley cropping species: Senna siamea, Leucaena leucocephala, Dactyladenia barteri and Flemingia macrophylla. Soil samples were incubated for 140 days at 25 °C and the soil microbial biomass was determined by the ninhydrin extraction method along the incubation period. The soil microbial biomass values ranged between 80 and 600 mg.kg-1 and followed, in all cases, the decreasing order: Leucaena> Senna> Flemingia> Dactyladenia.

  18. Daily dynamics of bacterial numbers, CO2 emissions from soil and relationships between their wavelike fluctuations and succession of the microbial community

    Science.gov (United States)

    Semenov, A. M.; Bubnov, I. A.; Semenov, V. M.; Semenova, E. V.; Zelenev, V. V.; Semenova, N. A.

    2013-08-01

    The daily dynamics of the number of copiotrophic and oligotrophic bacteria (in colony-forming units) and CO2 emissions from cultivated soils after short- and long-term disturbances were studied for 25-27 days in a microfield experiment. The relationship of the wavelike fluctuations of the bacterial number and CO2 emission with the succession of the soil microbial community was determined by the polymerase chain reaction method—denaturing gradient gel electrophoresis (PCR-DGGE). Short-term disturbances involved the application of organic or mineral fertilizers, pesticides, and plant residues to the soils of different plots. The long-term effect was a result of using biological and intensive farming systems for three years. The short-term disturbances resulted in increased peaks of the bacterial number, the significance of which was confirmed by harmonics analysis. The daily dynamics of the structure of the soil microbial community, which was studied for 27 days by the DGGE method, also had an oscillatory pattern. Statistical processing of the data (principal components analysis, harmonics and cross-correlation analyses) has revealed significant fluctuations in the structure of microbial communities coinciding with those of the bacterial populations. The structure of the microbial community changed within each peak of the dynamics of the bacterial number (but not from peak to peak), pointing to the cyclical character of the short-term succession. The long-term effects resulted in a less intense response of the microbiota—a lower rate of CO2 emission from the soil cultivated according to the organic farming system.

  19. Effect In Vitro of Antiparasitic Drugs on Microbial Inhibitor Test Responses for Screening Antibiotic Residues in Goat's Milk.

    Science.gov (United States)

    Romero, T; Beltrán, M C; Reybroeck, W; Molina, M P

    2015-09-01

    Microbial inhibitor tests are widely used to screen antibiotic residues in milk; however, these tests are nonspecific and may be affected by various substances capable of inhibiting the growth of the test microorganism. The objective of this study was to determine the effect of antiparasitic drugs in goat's milk on the microbial inhibitor test response. Raw antibiotic-free milk from Murciano-Granadina goats was supplemented with eight concentrations of seven antiparasitic substances (albendazole, 10 to 170 mg/kg; closantel, 1 to 140 mg/kg; diclazuril, 8 to 45 mg/kg; febendazole, 10 to 140 mg/kg; levamisole, 40 to 440 mg/kg; diazinon, 8 to 45 mg/kg; and ivermectin, 40 to 200 mg/kg). Twelve replicates for each concentration were analyzed with three microbial inhibitor tests: BRT MRL, Delvotest SP-NT MSC, and Eclipse 100. The results were interpreted visually (negative or positive). Using a logistic regression model, the concentrations of the antiparasitic drugs producing 5% (IC5), 10% (IC10), and 50% (IC50) positive results were determined. In general, the Eclipse 100 test was less sensitive to the effect of antiparasitic substances; the inhibitory concentrations of almost all the drugs assayed were higher than those for other tests. Conversely, the BRT MRL test was most affected, with high levels of interference at lower antiparasitic drug concentrations. Closantel and diazinon interfered with all microbial tests at lower concentrations than did other drugs (IC5 = 1 to 26 and 12 to 20 mg/kg, respectively), and higher concentrations of levamisole and diclazuril (IC5 = 30 to 240 and 50 to 117 mg/kg, respectively) were required to produce 5% positive results. These findings indicate that microbial inhibitor tests can be affected by elevated concentrations of antiparasitic drugs in goat's milk.

  20. [Comparisons of Microbial Numbers, Biomasses and Soil Enzyme Activities Between Paddy Field and Drvland Origins in Karst Cave Wetland].

    Science.gov (United States)

    Jin, Zhen-jiang; Zeng, Hong-hu; Li, Qiang; Cheng, Ya-ping; Tang, Hua-feng; Li, Min; Huang, Bing-fu

    2016-01-15

    The purpose of this study is to compare microbial number, microbial biomass as well as soil enzyme activity between paddy field and dryland originated karst wetland ecosystems. The soil samples (0-20 cm) of uncultivated wetland, paddy field and dryland were collected in Huixian karst cave wetland, Guilin, China. Microbial numbers and biomass were detected using dilute plate incubation counting and chloroform fumigation-extraction, respectively. Microbial DNA was extracted according to the manufacturer's instructions of the kit. Microbial activity was examined using soil enzyme assays as well. The result showed that the bacteria number in paddy filed was (4.36 +/- 2.25) x 10(7) CFU x g(-1), which was significantly higher than those in wetland and dryland. Fungi numbers were (6.41 +/- 2.16) x 10(4) CFU x g(-1) in rice paddy and (6.52 +/- 1.55) x 10(4) CFU x g(-1) in wetland, which were higher than that in dryland. Actinomycetes number was (2.65 +/- 0.72) x 10(6) CFU x g(-1) in dryland, which was higher than that in wetland. Microbial DNA concentration in rice paddy was (11.92 +/- 3.69) microg x g(-1), which was higher than that in dryland. Invertase activity was (66.87 +/- 18.61) mg x (g x 24 h)(-1) in rice paddy and alkaline phosphatase activity was (2.07 +/- 0.99) mg x (g x 2 h)(-1) in wetland, both of which were higher than those in dryland. Statistical analysis showed there was a significant positive correlation of microbial DNA content, alkaline phosphatase activity and microbial carbon with soil pH, soil organic carbon (SOC), total nitrogen, alkali-hydrolyzable nitrogen, soil moisture, exchangeable Ca2+ and exchangeable Mg2+, as well as a significant positive correlation of intervase activity with the former three microbial factors. The above results indicated that microbial biomass and function responded much more sensitively to land-use change than microbial number in karst cave wetland system. Soil moisture, SOC and some factors induced by land-use change

  1. Effect of phenotypic residual feed intake and dietary forage content on the rumen microbial community of beef cattle.

    Science.gov (United States)

    Carberry, Ciara A; Kenny, David A; Han, Sukkyan; McCabe, Matthew S; Waters, Sinead M

    2012-07-01

    Feed-efficient animals have lower production costs and reduced environmental impact. Given that rumen microbial fermentation plays a pivotal role in host nutrition, the premise that rumen microbiota may contribute to host feed efficiency is gaining momentum. Since diet is a major factor in determining rumen community structure and fermentation patterns, we investigated the effect of divergence in phenotypic residual feed intake (RFI) on ruminal community structure of beef cattle across two contrasting diets. PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) were performed to profile the rumen bacterial population and to quantify the ruminal populations of Entodinium spp., protozoa, Fibrobacter succinogenes, Ruminococcus flavefaciens, Ruminococcus albus, Prevotella brevis, the genus Prevotella, and fungi in 14 low (efficient)- and 14 high (inefficient)-RFI animals offered a low-energy, high-forage diet, followed by a high-energy, low-forage diet. Canonical correspondence and Spearman correlation analyses were used to investigate associations between physiological variables and rumen microbial structure and specific microbial populations, respectively. The effect of RFI on bacterial profiles was influenced by diet, with the association between RFI group and PCR-DGGE profiles stronger for the higher forage diet. qPCR showed that Prevotella abundance was higher (P diet. Thus, differences in the ruminal microflora may contribute to host feed efficiency, although this effect may also be modulated by the diet offered.

  2. Microbial dynamics in anaerobic digestion reactors for treating organic urban residues during the start-up process.

    Science.gov (United States)

    Alcántara-Hernández, R J; Taş, N; Carlos-Pinedo, S; Durán-Moreno, A; Falcón, L I

    2017-06-01

    Anaerobic digestion of organic residues offers economic benefits via biogas production, still methane (CH 4 ) yield relies on the development of a robust microbial consortia for adequate substrate degradation, among other factors. In this study, we monitor biogas production and changes in the microbial community composition in two semi-continuous stirred tank reactors during the setting process under mesophilic conditions (35°C) using a 16S rDNA high-throughput sequencing method. Reactors were initially inoculated with anaerobic granular sludge from a brewery wastewater treatment plant, and gradually fed organic urban residues (4·0 kg VS m -3  day -1 ) . The inocula and biomass samples showed changes related to adaptations of the community to urban organic wastes including a higher relative proportion of Clostridiales, with Ruminococcus spp. and Syntrophomonas spp. as recurrent species. Candidatus Cloacamonas spp. (Spirochaetes) also increased from ~2·2% in the inoculum to >10% in the reactor biomass. The new community consolidated the cellulose degradation and the propionate and amino acids fermentation processes. Acetoclastic methanogens were more abundant in the reactor, where Methanosaeta spp. was found as a key player. This study demonstrates a successful use of brewery treatment plant granular sludge to obtain a robust consortium for methane production from urban organic solid waste in Mexico. This study describes the selection of relevant bacteria and archaea in anaerobic digesters inoculated with anaerobic granular sludge from a brewery wastewater treatment plant. Generally, these sludge granules are used to inoculate reactors digesting organic urban wastes. Though, it is still not clearly understood how micro-organisms respond to substrate variations during the reactor start-up process. After feeding two reactors with organic urban residues, it was found that a broader potential for cellulose degradation was developed including Bacteroidetes

  3. Conversion of SPORL pretreated Douglas fir forest residues into microbial lipids with oleaginous yeasts

    Science.gov (United States)

    Bruce S. Dien; Junyong Zhu; Patricia J. Slininger; Cletus P. Kurtzman; Bryan R. Moser; Patricia J. O' Bryan; Roland Gleisner; Michael A. Cotta

    2016-01-01

    Douglas fir is the dominant commercial tree grown in the United States. In this study Douglas fir residue was converted to single cell oils (SCO) using oleaginous yeasts. Monosaccharides were extracted from the woody biomass by pretreating with sulfite and dilute sulfuric acid (SPORL process) and hydrolyzing using commercial cellulases. A new SPORL process that uses pH...

  4. Effects of Bioreactor Retention Time on Aerobic Microbial Decomposition of CELSS Crop Residues

    Science.gov (United States)

    Strayer, R. F.; Finger, B. W.; Alazraki, M. P.

    1997-01-01

    The focus of resource recovery research at the KSC-CELSS Breadboard Project has been the evaluation of microbiologically mediated biodegradation of crop residues by manipulation of bioreactor process and environmental variables. We will present results from over 3 years of studies that used laboratory- and breadboard-scale (8 and 120 L working volumes, respectively) aerobic, fed-batch, continuous stirred tank reactors (CSTR) for recovery of carbon and minerals from breadboard grown wheat and white potato residues. The paper will focus on the effects of a key process variable, bioreactor retention time, on response variables indicative of bioreactor performance. The goal is to determine the shortest retention time that is feasible for processing CELSS crop residues, thereby reducing bioreactor volume and weight requirements. Pushing the lower limits of bioreactor retention times will provide useful data for engineers who need to compare biological and physicochemical components. Bioreactor retention times were manipulated to range between 0.25 and 48 days. Results indicate that increases in retention time lead to a 4-fold increase in crop residue biodegradation, as measured by both dry weight losses and CO2 production. A similar overall trend was also observed for crop residue fiber (cellulose and hemicellulose), with a noticeable jump in cellulose degradation between the 5.3 day and 10.7 day retention times. Water-soluble organic compounds (measured as soluble TOC) were appreciably reduced by more than 4-fold at all retention times tested. Results from a study of even shorter retention times (down to 0.25 days), in progress, will also be presented.

  5. Inhibition of residual n-hexane in anaerobic digestion of lipid-extracted microalgal wastes and microbial community shift.

    Science.gov (United States)

    Yun, Yeo-Myeong; Shin, Hang-Sik; Lee, Chang-Kyu; Oh, You-Kwan; Kim, Hyun-Woo

    2016-04-01

    Converting lipid-extracted microalgal wastes to methane (CH4) via anaerobic digestion (AD) has the potential to make microalgae-based biodiesel platform more sustainable. However, it is apparent that remaining n-hexane (C6H14) from lipid extraction could inhibit metabolic pathway of methanogens. To test an inhibitory influence of residual n-hexane, this study conducted a series of batch AD by mixing lipid-extracted Chlorella vulgaris with a wide range of n-hexane concentration (∼10 g chemical oxygen demand (COD)/L). Experimental results show that the inhibition of n-hexane on CH4 yield was negligible up to 2 g COD/L and inhibition to methanogenesis became significant when it was higher than 4 g COD/L based on quantitative mass balance. Inhibition threshold was about 4 g COD/L of n-hexane. Analytical result of microbial community profile revealed that dominance of alkane-degrading sulfate-reducing bacteria (SRB) and syntrophic bacteria increased, while that of methanogens sharply dropped as n-hexane concentration increased. These findings offer a useful guideline of threshold n-hexane concentration and microbial community shift for the AD of lipid-extracted microalgal wastes.

  6. Microbial community response to a release of neat ethanol onto residual hydrocarbons in a pilot-scale aquifer tank.

    Science.gov (United States)

    Cápiro, Natalie L; Da Silva, Marcio L B; Stafford, Brent P; Rixey, William G; Alvarez, Pedro J J

    2008-09-01

    The microbial community response to a neat ethanol release (E100, 76 l) onto residual hydrocarbons in sandy soil was evaluated in a continuous-flow 8 m(3) pilot-scale aquifer tank, simulating a release at a bulk fuel terminal. Microbial genotypic shifts were assessed using quantitative real-time PCR analysis. High ethanol concentrations in the capillary fringe at potentially toxic levels, exceeding 100,000 mg l(-1), were tolerated by the microbial community. The high biochemical oxygen demand exerted by ethanol rapidly induced anaerobic conditions, and both methane production (up to 1.2 mg l(-1)) and growth of putative methanogenic Archaea (up to 10(6) gene copies per g of soil) were observed in shallow groundwater and soil samples 75 cm down gradient from the source. Aerobic conditions returned after ethanol was flushed out of the system, approximately 45 days after the spill (less than 7.5 pore volumes flushed). Total Bacteria growth coincided with ethanol migration and availability, which was restricted to a relatively thin layer at the capillary fringe and water table interface. The concentrations of bacteria harbouring the aerobic catabolic genes dmpN (coding for phenol hydroxylase) and to dC1 (coding for toluene dioxygenase) increased (up to 100x) down gradient from the source, likely as a result of both fortuitous growth on ethanol and on aromatic hydrocarbons mobilized by ethanol. Growth of hydrocarbon degraders was corroborated by denaturing gradient gel electrophoresis analysis showing proliferation of Azospirillum and Brevundimonas spp., which are bacteria commonly associated with microaerophilic hydrocarbon degradation. Nevertheless, the relative abundance of hydrocarbon-specific degraders (as a fraction of total Bacteria) decreased as other bacteria grew to a higher extent. Overall, the observed growth of hydrocarbon degraders suggests a potential enhancement in aerobic natural attenuation in shallow aquifers after ethanol and its degradation by

  7. Microbial screening for quinolones residues in cow milk by bio-optical method.

    Science.gov (United States)

    Appicciafuoco, Brunella; Dragone, Roberto; Frazzoli, Chiara; Bolzoni, Giuseppe; Mantovani, Alberto; Ferrini, Anna Maria

    2015-03-15

    The use of antibiotics on lactating cows should be monitored for the possible risk of milk contamination with residues. Accordingly, Maximum Residue Levels (MRLs) are established by the European Commission to guarantee consumers safety. As pointed out by Dec 2002/657/EC, screening is the first step in the strategy for antibiotic residue control, thus playing a key role in the whole control procedure. However, current routine screening methods applied in milk chain still fail to detect residues of quinolones at concentrations of interest. This paper reports the findings of a new bio-optical method for the screening of quinolones residues in bovine milk, based on E. coli ATCC 11303 growth inhibition. The effect of blank and spiked cow milk samples (aliquots equivalents to 0.8%, v/v) is evaluated in Mueller Hinton Broth (MHb) and MHb enriched with MgSO4 2% (MHb-Mg) inoculated with the test strain at the concentration of 10(4)CFU/mL. The presence of quinolones inhibits the cellular growth in MHb, while this effect is neutralized in MHb-Mg allowing both detection and presumptive identification of quinolones. Growth of the test strain is monitored at 37 °C in a Bioscreen C automated system, and Optical Density (OD) at 600 nm is recorded every 10 min after shaking for 10s. Growth curves (OD vs. time) of E. coli ATCC 11303 are assessed in milk samples, with and without quinolones, and their differences in terms of ΔOD (ΔOD600nm=ODMHb-Mg-ODMHb) are calculated. The presence of quinolones is detected by the cellular growth inhibition (OD vs time, none increase in the value OD) and presumptively identified through the increase of the slope of ΔOD600nm curve (ΔOD vs. time), after about 3h of incubation. The detection limit for ciprofloxacin and enrofloxacin is at the level of MRL, for marbofloxacin is at 2-fold the MRL whereas for danofloxacin is at 4-fold the MRL. Although the sensitivity of the method could be further improved and the procedure automated, it is a

  8. A new microbial screening method for the detection of antimicrobial residues in slaughter animals: The Nouws antibiotic test (NAT-screening)

    NARCIS (Netherlands)

    Pikkemaat, M.G.; Oostra-van Dijk, S.; Schouten, J.; Rapallini, M.; Egmond, van H.J.

    2008-01-01

    An improved microbial method for the screening of antimicrobial residues in slaughter animals has been developed. The Nouws antibiotic test (NAT-screening) is based on the analysis of renal pelvis fluid and comprises five test plates enabling group specific identification. The NAT-screening combines

  9. A new VLSI complex integer multiplier which uses a quadratic-polynomial residue system with Fermat numbers

    Science.gov (United States)

    Shyu, H. C.; Reed, I. S.; Truong, T. K.; Hsu, I. S.; Chang, J. J.

    1987-01-01

    A quadratic-polynomial Fermat residue number system (QFNS) has been used to compute complex integer multiplications. The advantage of such a QFNS is that a complex integer multiplication requires only two integer multiplications. In this article, a new type Fermat number multiplier is developed which eliminates the initialization condition of the previous method. It is shown that the new complex multiplier can be implemented on a single VLSI chip. Such a chip is designed and fabricated in CMOS-Pw technology.

  10. Changes in bacterial numbers and microbial activity of pig slurry during gut transit of epigeic and anecic earthworms.

    Science.gov (United States)

    Aira, Manuel; Monroy, Fernando; Domínguez, Jorge

    2009-03-15

    In soils, organic matter decomposition and stabilization largely occur as a result of microbial activity, although when present, earthworms are important drivers of the processes through their interactions with microflora which begin during organic matter digestion by earthworms. Here, we studied the effects of gut transit on the number of bacteria and the microbial activity in pig slurry, using three epigeic (Eisenia fetida, Eisenia andrei, Eudrilus eugeniae) and one anecic (Octodrilus complanatus) species of earthworm. Bacterial counts revealed that the effect of gut transit on microbes differed depending on the earthworm species. Thus, no changes in the number of bacteria were found in the gut contents of E. fetida and E. eugeniae, whereas large decreases were recorded in those of O. complanatus and E. andrei (2.7 and 1.3 times, respectively). We suggest that, unlike in the three epigeic earthworm species, microorganisms are preferentially utilized by O. complanatus to meet its nutrient requirements, because of its limited digestive capacity. Despite the decrease in bacterial numbers, there were no differences in the gut contents of the four earthworm species or undigested pig slurry in terms of dehydrogenase activity. Therefore, we suggest that after gut transit in the four earthworm species under study the potential microbial degradation of pig slurry remains unaltered.

  11. Comparative analyses of microbial structures and gene copy numbers in the anaerobic digestion of various types of sewage sludge.

    Science.gov (United States)

    Hidaka, Taira; Tsushima, Ikuo; Tsumori, Jun

    2018-04-01

    Anaerobic co-digestion of various sewage sludges is a promising approach for greater recovery of energy, but the process is more complicated than mono-digestion of sewage sludge. The applicability of microbial structure analyses and gene quantification to understand microbial conditions was evaluated. The results show that information from gene analyses is useful in managing anaerobic co-digestion and damaged microbes in addition to conventional parameters like total solids, pH and biogas production. Total bacterial 16S rRNA gene copy numbers are the most useful tools for evaluating unstable anaerobic digestion of sewage sludge, rather than mcrA and total archaeal 16S rRNA gene copy numbers, and high-throughput sequencing. First order decay rates of gene copy numbers during pH failure were higher than typical decay rates of microbes in stable operation. The sequencing analyses, including multidimensional scaling, showed very different microbial structure shifts, but the results were not consistent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Design and characterization of a microbial fuel cell for the conversion of a lignocellulosic crop residue to electricity.

    Science.gov (United States)

    Gregoire, K P; Becker, J G

    2012-09-01

    Agricultural crop residues contain high amounts of biochemical energy as cellulose and lignin. A portion of this biomass could be sustainably harvested for conversion to bioenergy to help offset fossil fuel consumption. In this study, the potential for converting lignocellulosic biomass directly to electricity in a microbial fuel cell (MFC) was explored. Design elements of tubular air cathode MFCs and leach-bed bioreactors were integrated to develop a new solid-substrate MFC in which cellulose hydrolysis, fermentation, and anode respiration occurred in a single chamber. Electricity was produced continuously from untreated corncob pellets for >60 d. Addition of rumen fluid increased power production, presumably by providing growth factors to anode-respiring bacteria. Periodic exposure to oxygen also increased power production, presumably by limiting the diversion of electrons to methanogenesis. In the absence of methanogenesis, bioaugmentation with Geobacter metallireducens further improved MFC performance. Under these conditions, the maximum power density was 230 mW/m(3). Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Conversion of residual organics in corn stover-derived biorefinery stream to bioenergy via microbial fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Borole, Abhijeet P [ORNL; Hamilton, Choo Yieng [ORNL; Schell, Daniel J [National Renewable Energy Laboratory (NREL)

    2012-01-01

    A biorefinery process typically uses about 4-10 times as much water as the amount of biofuel generated. The wastewater produced in a biorefinery process contains residual sugars, 5-furfural, phenolics, and other pretreatment and fermentation byproducts. Treatment of the wastewater can reduce the need for fresh water and potentially add to the environmental benefits of the process. Use of microbial fuel cells (MFCs) for conversion of the various organics present in a post-fermentation biorefinery stream is reported here. The organic loading was varied over a wide range to assess removal efficiency, coulombic efficiency and power production. A coulombic efficiency of 40% was observed for a low loading of 1% (0.66 g/L) and decreased to 1.8% for the undiluted process stream (66.4 g/L organic loading). A maximum power density of 1180 mW/m2 was observed at a loading of 8%. Excessive loading was found to result in poor electrogenic performance. The results indicate that operation of an MFC at an intermediate loading using dilution and recirculation of the process stream can enable effective treatment with bioenergy recovery.

  14. Biodegradation pattern of hydrocarbons from a fuel oil-type complex residue by an emulsifier-producing microbial consortium.

    Science.gov (United States)

    Nievas, M L; Commendatore, M G; Esteves, J L; Bucalá, V

    2008-06-15

    The biodegradation of a hazardous waste (bilge waste), a fuel oil-type complex residue from normal ship operations, was studied in a batch bioreactor using a microbial consortium in seawater medium. Experiments with initial concentrations of 0.18 and 0.53% (v/v) of bilge waste were carried out. In order to study the biodegradation kinetics, the mass of n-alkanes, resolved hydrocarbons and unresolved complex mixture (UCM) hydrocarbons were assessed by gas chromatography (GC). Emulsification was detected in both experiments, possibly linked to the n-alkanes depletion, with differences in emulsification start times and extents according to the initial hydrocarbon concentration. Both facts influenced the hydrocarbon biodegradation kinetics. A sequential biodegradation of n-alkanes and UMC was found for the higher hydrocarbon content. Being the former growth associated, while UCM biodegradation was a non-growing process showing enzymatic-type biodegradation kinetics. For the lower hydrocarbon concentration, simultaneous biodegradation of n-alkanes and UMC were found before emulsification. Nevertheless, certain UCM biodegradation was observed after the medium emulsification. According to the observed kinetics, three main types of hydrocarbons (n-alkanes, biodegradable UCM and recalcitrant UCM) were found adequate to represent the multicomponent substrate (bilge waste) for future modelling of the biodegradation process.

  15. New capillary number definition for displacement of residual nonwetting phase in natural fractures

    NARCIS (Netherlands)

    Alquaimi, B.; Rossen, W.R.

    2017-01-01

    We propose a new capillary number for flow in fractures starting with a force balance on a trapped ganglion in a fracture. The new definition is validated with laboratory experiments using five distinctive model fractures. Capillary desaturation curves were generated experimentally using

  16. A Small Number of Residues Can Determine if Linker Histones Are Bound On or Off Dyad in the Chromatosome.

    Science.gov (United States)

    Zhou, Bing-Rui; Feng, Hanqiao; Ghirlando, Rodolfo; Li, Shipeng; Schwieters, Charles D; Bai, Yawen

    2016-10-09

    Linker histones bind to the nucleosome and regulate the structure and function of chromatin. We have previously shown that the globular domains of chicken H5 and Drosophila H1 linker histones bind to the nucleosome with on- or off-dyad modes, respectively. To explore the determinant for the distinct binding modes, we investigated the binding of a mutant globular domain of H5 to the nucleosome. This mutant, termed GH5_pMut, includes substitutions of five globular domain residues of H5 with the corresponding residues in the globular domain of Drosophila H1. The residues at these five positions play important roles in nucleosome binding by either H5 or Drosophila H1. NMR and spin-labeling experiments showed that GH5_pMut bound to the nucleosome off the dyad. We further found that the nucleosome array condensed by either the GH5_pMut or the globular domain of Drosophila H1 displayed a similar sedimentation coefficient, whereas the same nucleosome array condensed by the wild-type globular domain of H5 showed a much larger sedimentation coefficient. Moreover, NMR and spin-labeling results from the study of the nucleosome in complex with the full-length human linker histone H1.0, whose globular domain shares high sequence conservation with the corresponding globular domain of H5, are consistent with an on-dyad binding mode. Taken together, our results suggest that a small number of residues in the globular domain of a linker histone can control its binding location on the nucleosome and higher-order chromatin structure. Copyright © 2016. Published by Elsevier Ltd.

  17. Characterization of Volume F Trash from Four Recent STS Missions: Microbial Occurrence, Numbers, and Identifications

    Science.gov (United States)

    Strayer, Richard F.; Hummerick, Mary E.; Richards, Jeffrey T.; McCoy, LaShelle E.; Roberts, Michael S.; Wheeler, Raymond M.

    2011-01-01

    The fate of space-generated solid wastes, including trash, for future missions is under consideration by NASA. Several potential treatment options are under active technology development. Potential fates for space-generated solid wastes: Storage without treatment; storage after treatment(s) including volume reduction, water recovery, sterilization, and recovery plus recycling of waste materials. For this study, a microbial characterization was made on trash returned from four recent STS missions. The material analyzed were 'Volume F' trash and other bags of accompanying trash. This is the second of two submitted papers on these wastes. This first one covered trash content, weight and water content. Upon receipt, usually within 2 days of landing, trash contents were catalogued and placed into categories: drink containers, food waste, personal hygiene items, and packaging materials, i.e., plastic film and duct tape. Microbial counts were obtained with cultivatable counts on agar media and direct counts using Acridine Orange fluorescent stain (AODC). Trash bag surfaces, 25 square cm , were also sampled. Direct counts were approximately 1 x 10(exp 6) microbes/square cm and cultivatable counts ranged from 1 x 10 to 1 X 10(exp 4) microbes/ square cm-2. Aerobic microbes, aerobic sporeformers, and yeasts plus molds were common for all four missions. Waste items from each category were placed into sterile ziplock bags and 1.5 L sterile DI water added. These were then dispersed by hand shaking for 2 min. prior to inoculation of count media or determining AODC. In general, cultivatable microbes were found in drinks, food wastes, and personal hygiene items. Direct counts were usually higher than cultivatable counts. Some pathogens were found: Staphylococcus auerus, Escherichia coli (fecal wastes). Count ranges: drink pouches - AODC 2 x 10(exp 6) to 1 X 10(exp 8) g(sub fw) (exp -1); cultivatable counts variable between missions; food wastes: Direct counts were close to aerobic

  18. Detection of large numbers of novel sequences in the metatranscriptomes of complex marine microbial communities.

    Science.gov (United States)

    Gilbert, Jack A; Field, Dawn; Huang, Ying; Edwards, Rob; Li, Weizhong; Gilna, Paul; Joint, Ian

    2008-08-22

    Sequencing the expressed genetic information of an ecosystem (metatranscriptome) can provide information about the response of organisms to varying environmental conditions. Until recently, metatranscriptomics has been limited to microarray technology and random cloning methodologies. The application of high-throughput sequencing technology is now enabling access to both known and previously unknown transcripts in natural communities. We present a study of a complex marine metatranscriptome obtained from random whole-community mRNA using the GS-FLX Pyrosequencing technology. Eight samples, four DNA and four mRNA, were processed from two time points in a controlled coastal ocean mesocosm study (Bergen, Norway) involving an induced phytoplankton bloom producing a total of 323,161,989 base pairs. Our study confirms the finding of the first published metatranscriptomic studies of marine and soil environments that metatranscriptomics targets highly expressed sequences which are frequently novel. Our alternative methodology increases the range of experimental options available for conducting such studies and is characterized by an exceptional enrichment of mRNA (99.92%) versus ribosomal RNA. Analysis of corresponding metagenomes confirms much higher levels of assembly in the metatranscriptomic samples and a far higher yield of large gene families with >100 members, approximately 91% of which were novel. This study provides further evidence that metatranscriptomic studies of natural microbial communities are not only feasible, but when paired with metagenomic data sets, offer an unprecedented opportunity to explore both structure and function of microbial communities--if we can overcome the challenges of elucidating the functions of so many never-seen-before gene families.

  19. Detection of large numbers of novel sequences in the metatranscriptomes of complex marine microbial communities.

    Directory of Open Access Journals (Sweden)

    Jack A Gilbert

    2008-08-01

    Full Text Available Sequencing the expressed genetic information of an ecosystem (metatranscriptome can provide information about the response of organisms to varying environmental conditions. Until recently, metatranscriptomics has been limited to microarray technology and random cloning methodologies. The application of high-throughput sequencing technology is now enabling access to both known and previously unknown transcripts in natural communities.We present a study of a complex marine metatranscriptome obtained from random whole-community mRNA using the GS-FLX Pyrosequencing technology. Eight samples, four DNA and four mRNA, were processed from two time points in a controlled coastal ocean mesocosm study (Bergen, Norway involving an induced phytoplankton bloom producing a total of 323,161,989 base pairs. Our study confirms the finding of the first published metatranscriptomic studies of marine and soil environments that metatranscriptomics targets highly expressed sequences which are frequently novel. Our alternative methodology increases the range of experimental options available for conducting such studies and is characterized by an exceptional enrichment of mRNA (99.92% versus ribosomal RNA. Analysis of corresponding metagenomes confirms much higher levels of assembly in the metatranscriptomic samples and a far higher yield of large gene families with >100 members, approximately 91% of which were novel.This study provides further evidence that metatranscriptomic studies of natural microbial communities are not only feasible, but when paired with metagenomic data sets, offer an unprecedented opportunity to explore both structure and function of microbial communities--if we can overcome the challenges of elucidating the functions of so many never-seen-before gene families.

  20. Microbial aerosol liberation from soiled textiles isolated during routine residuals handling in a modern health care setting.

    Science.gov (United States)

    Handorean, Alina; Robertson, Charles E; Harris, J Kirk; Frank, Daniel; Hull, Natalie; Kotter, Cassandra; Stevens, Mark J; Baumgardner, Darrel; Pace, Norman R; Hernandez, Mark

    2015-12-09

    A wide variety of specialty textiles are used in health care settings for bedding, clothing, and privacy. The ability of textiles to host or otherwise sequester microbes has been well documented; however, their reciprocal potential for liberating airborne bacteria remains poorly characterized. In response, a multi-season survey of bacterial bioaerosols was conducted in the origin and terminus of residual paths which are specifically designed to isolate soiled hospital textiles as they are moved to laundering. This survey used conventional optical particle counting which incorporated multi-channel fluorescence in conjunction with molecular phylogenetic analyses to characterize the bioaerosols liberated during soiled textile storage--immediately before and after the occupation of a modern hospital. Although outfitted with a HEPA filtration system, the number of airborne particles presenting fluorescing optical signatures consistent with airborne bacteria and fungi significantly increased in textile holding rooms soon after the hospital's commissioning, even though these isolated residual areas rarely host personnel. The bioaerosol liberated during textile storage was characterized using Illumina MiSeq sequencing of bacterial 16S ribosomal ribonucleic acid (rRNA) genes. Gene copies recovered by quantitative PCR from aerosol collected in co-located impingers were consistent with fluorescence gated optical particle counting. The relative abundance patterns of proximal bacterial bioaerosol were such that the air in the origin and terminus of textile storage rooms could not be differentiated once the hospital began processing soiled linens. Genes from microbes typically associating with human skin, feces, and hair--Staphylococcus, Propionibacteria, Corynebacteria, Lactobacillus, and Streptococcus spp.--dominated the aerosol abundance profiles in textile holding rooms, which were generally far less diverse than communities recovered from surfaces in patient rooms. These

  1. Production of novel microbial flocculants by Klebsiella sp. TG-1 using waste residue from the food industry and its use in defecating the trona suspension.

    Science.gov (United States)

    Liu, Zhan-Ying; Hu, Zhi-Quan; Wang, Tao; Chen, Yan-Ying; Zhang, Jianbin; Yu, Jing-Ran; Zhang, Tong; Zhang, Yong-Feng; Li, Yong-Li

    2013-07-01

    A microbial-flocculants-producing (MBF-producing) bacterium, named TG-1, was isolated from waste water of a starch factory, and identified as Klebsiella sp. TG-1. The microbial flocculants (MBF) produced by TG-1, named as MBF-TG-1, was applied to defecating the strong basic trona suspension in the trona industry. After optimizing medium and culturing conditions with single-factor and orthogonal designs, the highest flocculation rate of 86.9% was achieved. Chemical analysis showed that the purified microbial flocculants (MBF-TG-1) was mainly composed of polysaccharides (84.6%), with a small amount of protein or amino acid (11.1%). Bridging mechanism was supposed as the main flocculation mechanism by analyzing the flocculation process and the biochemistry properties of MBF-TG-1. The high flocculation rate (84%) was also achieved with a low-cost medium (the solid residue of tofu production from food industry). Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Number of residual thermotolerant coliforms on plants and in soil when using reclaimed domestic wastewater for irrigation.

    Science.gov (United States)

    Khamkure, Sasirot; Cervantes, Edmundo Peña; Zermeño González, Alejandro; Cervantes, Rubén López; Melo, Prócoro Gamero; Ramírez, Homero

    2013-01-01

    The reclamation of domestic wastewater for irrigation is one alternative approach to solve the water scarcity crisis, but it is essential to control the microbiological quality of wastewater used for irrigation. The removal of thermotolerant coliforms, also known as faecal coliforms (FC), from treated domestic wastewater by intermittent media infiltration (IMI) in column was studied. The columns were filled with natural filter media (soil, soil/charcoal and zinc-modified zeolite, Zeo-Zn), and wastewater, IMI-treated wastewater and disinfected wastewater were compared. The numbers of residual FC on Swiss chard (Beta vulgaris) and in agricultural soil were determined over a 4-month period. The column using Zeo-Zn had a higher FC removal efficiency (2.98 log) than columns with other filter media and disinfection (1.87-2.57 log) due to the bactericidal properties of Zn(2+). The treatment of wastewater using Zeo-Zn and disinfection both decreased the accumulation of FC on plants and in soil to approximately 1-20 MPN/g dry matter. IMI-treated wastewater using the column with Zeo-Zn was suitable for unrestricted agricultural use, complied with Mexican regulations (as did disinfected wastewater) and had a low risk of FC contamination of plants and soil.

  3. Preservatives and neutralizing substances in milk: analytical sensitivity of official specific and nonspecific tests, microbial inhibition effect, and residue persistence in milk

    Directory of Open Access Journals (Sweden)

    Livia Cavaletti Corrêa da Silva

    2015-09-01

    Full Text Available Milk fraud has been a recurring problem in Brazil; thus, it is important to know the effect of most frequently used preservatives and neutralizing substances as well as the detection capability of official tests. The objective of this study was to evaluate the analytical sensitivity of legislation-described tests and nonspecific microbial inhibition tests, and to investigate the effect of such substances on microbial growth inhibition and the persistence of detectable residues after 24/48h of refrigeration. Batches of raw milk, free from any contaminant, were divided into aliquots and mixed with different concentrations of formaldehyde, hydrogen peroxide, sodium hypochlorite, chlorine, chlorinated alkaline detergent, or sodium hydroxide. The analytical sensitivity of the official tests was 0.005%, 0.003%, and 0.013% for formaldehyde, hydrogen peroxide, and hypochlorite, respectively. Chlorine and chlorinated alkaline detergent were not detected by regulatory tests. In the tests for neutralizing substances, sodium hydroxide could not be detected when acidity was accurately neutralized. The yogurt culture test gave results similar to those obtained by official tests for the detection of specific substances. Concentrations of 0.05% of formaldehyde, 0.003% of hydrogen peroxide and 0.013% of sodium hypochlorite significantly reduced (P

  4. Comparative Study of Microbial Activity and Chemical Properties of Soil by Implementing Anti-erosion Measure Vertical Mulching with Organic Residues

    Directory of Open Access Journals (Sweden)

    Gergana Slavova Kuncheva

    2015-01-01

    Full Text Available Water soil erosion is a phenomenon in which soil particles are separated transported and translocated by the action of rain water. Removal of topsoil by water flow leads to a decrease of humus in the soil, deterioration of soil structure, compaction, and reduction of microbial activity.Developed and tested have been number of methods and technologies for soil protection from the effects of water erosion. Such technology is vertical mulching, and straw or compost applied as mulching material.This work is a study of the changes that occur in some soil chemical properties and soil microbiological activity, as a result in the implementation of anti-erosion measure vertical mulching with different mulching materials for growing corn and wheat grain on carbonate chernozem, on sloping agricultural lands.

  5. Anodic biofilms in microbial fuel cells harbor low numbers of higher-power-producing bacteria than abundant genera

    KAUST Repository

    Kiely, Patrick D.

    2010-07-15

    Microbial fuel cell (MFC) anode communities often reveal just a few genera, but it is not known to what extent less abundant bacteria could be important for improving performance. We examined the microbial community in an MFC fed with formic acid for more than 1 year and determined using 16S rRNA gene cloning and fluorescent in situ hybridization that members of the Paracoccus genus comprised most (~30%) of the anode community. A Paracoccus isolate obtained from this biofilm (Paracoccus denitrificans strain PS-1) produced only 5.6 mW/m 2, whereas the original mixed culture produced up to 10 mW/m 2. Despite the absence of any Shewanella species in the clone library, we isolated a strain of Shewanella putrefaciens (strain PS-2) from the same biofilm capable of producing a higher-power density (17.4 mW/m2) than the mixed culture, although voltage generation was variable. Our results suggest that the numerical abundance of microorganisms in biofilms cannot be assumed a priori to correlate to capacities of these predominant species for high-power production. Detailed screening of bacterial biofilms may therefore be needed to identify important strains capable of high-power generation for specific substrates. © 2010 Springer-Verlag.

  6. The One-carbon Carrier Methylofuran from Methylobacterium extorquens AM1 Contains a Large Number of α- and γ-Linked Glutamic Acid Residues*

    Science.gov (United States)

    Hemmann, Jethro L.; Saurel, Olivier; Ochsner, Andrea M.; Stodden, Barbara K.; Kiefer, Patrick; Milon, Alain; Vorholt, Julia A.

    2016-01-01

    Methylobacterium extorquens AM1 uses dedicated cofactors for one-carbon unit conversion. Based on the sequence identities of enzymes and activity determinations, a methanofuran analog was proposed to be involved in formaldehyde oxidation in Alphaproteobacteria. Here, we report the structure of the cofactor, which we termed methylofuran. Using an in vitro enzyme assay and LC-MS, methylofuran was identified in cell extracts and further purified. From the exact mass and MS-MS fragmentation pattern, the structure of the cofactor was determined to consist of a polyglutamic acid side chain linked to a core structure similar to the one present in archaeal methanofuran variants. NMR analyses showed that the core structure contains a furan ring. However, instead of the tyramine moiety that is present in methanofuran cofactors, a tyrosine residue is present in methylofuran, which was further confirmed by MS through the incorporation of a 13C-labeled precursor. Methylofuran was present as a mixture of different species with varying numbers of glutamic acid residues in the side chain ranging from 12 to 24. Notably, the glutamic acid residues were not solely γ-linked, as is the case for all known methanofurans, but were identified by NMR as a mixture of α- and γ-linked amino acids. Considering the unusual peptide chain, the elucidation of the structure presented here sets the basis for further research on this cofactor, which is probably the largest cofactor known so far. PMID:26895963

  7. An Alternative Approach to Non-Log-Linear Thermal Microbial Inactivation: Modelling the Number of Log Cycles Reduction with Respect to Temperature

    Directory of Open Access Journals (Sweden)

    Vasilis Panagiotis Valdramidis

    2005-01-01

    Full Text Available A mathematical approach incorporating the shoulder effect during the quantification of microbial heat inactivation is being developed based on »the number of log cycles of reduction « concept. Hereto, the heat resistance of Escherichia coli K12 in BHI broth has been quantitatively determined in a generic and accurate way by defining the time t for x log reductions in the microbial population, i.e. txD, as a function of the treatment temperature T. Survival data of the examined microorganism are collected in a range of temperatures between 52–60.6 °C. Shoulder length Sl and specific inactivation rate kmax are derived from a mathematical expression that describes a non-log-linear behaviour. The temperature dependencies of Sl and kmax are used for structuring the txD(T function. Estimation of the txD(T parameters through a global identification procedure permits reliable predictions of the time to achieve a pre-decided microbial reduction. One of the parameters of the txD(T function is proposed as »the reference minimum temperature for inactivation«. For the case study considered, a value of 51.80 °C (with a standard error, SE, of 3.47 was identified. Finally, the time to achieve commercial sterilization and pasteurization for the product at hand, i.e. BHI broth, was found to be 11.70 s (SE=5.22, and 5.10 min (SE=1.22, respectively. Accounting for the uncertainty (based on the 90 % confidence intervals, CI a fail-safe treatment of these two processes takes 20.36 s and 7.12 min, respectively.

  8. Power from wastewater and residual products

    DEFF Research Database (Denmark)

    Krogh-Jeppesen, K.

    2007-01-01

    Microbial fuel cells utilise wastewater and residual products from the pretreatment of straw to generate power. Denmark could lead the way......Microbial fuel cells utilise wastewater and residual products from the pretreatment of straw to generate power. Denmark could lead the way...

  9. Residual basins

    International Nuclear Information System (INIS)

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  10. Residual deposits (residual soil)

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1988-01-01

    Residual soil deposits is accumulation of new formate ore minerals on the earth surface, arise as a result of chemical decomposition of rocks. As is well known, at the hyper genes zone under the influence of different factors (water, carbonic acid, organic acids, oxygen, microorganism activity) passes chemical weathering of rocks. Residual soil deposits forming depends from complex of geologic and climatic factors and also from composition and physical and chemical properties of initial rocks

  11. Effects of Synchronization of Carbohydrate and Protein Supply in Total Mixed Ration with Korean Rice Wine Residue on Ruminal Fermentation, Nitrogen Metabolism and Microbial Protein Synthesis in Holstein Steers

    Science.gov (United States)

    Piao, Min Yu; Kim, Hyun J.; Seo, J. K.; Park, T. S.; Yoon, J. S.; Kim, K. H.; Ha, Jong K.

    2012-01-01

    Three Holstein steers in the growing phase, each with a ruminal cannula, were used to test the hypothesis that the synchronization of the hourly rate of carbohydrate and nitrogen (N) released in the rumen would increase the amount of retained nitrogen for growth and thus improve the efficiency of microbial protein synthesis (EMPS). In Experiment 1, in situ degradability coefficients of carbohydrate and N in feeds including Korean rice wine residue (RWR) were determined. In Experiment 2, three total mixed ration (TMR) diets having different rates of carbohydrate and N release in the rumen were formulated using the in situ degradability of the feeds. All diets were made to contain similar contents of crude protein (CP) and neutral detergent fiber (NDF) but varied in their hourly pattern of nutrient release. The synchrony index of the three TMRs was 0.51 (LS), 0.77 (MS) and 0.95 (HS), respectively. The diets were fed at a restricted level (2% of the animal’s body weight) in a 3×3 Latin-square design. Synchronizing the hourly supply of energy and N in the rumen did not significantly alter the digestibility of dry matter, organic matter, crude protein, NDF or acid detergent fiber (ADF) (p>0.05). The ruminal NH3-N content of the LS group at three hours after feeding was significantly higher (pruminal NH3-N, pH and VFA concentration among the three groups were not significantly different (p>0.05). In addition, the purine derivative (PD) excretion in urine and microbial-N production (MN) among the three groups were not significantly different (p>0.05). In conclusion, synchronizing dietary energy and N supply to the rumen did not have a major effect on nutrient digestion or microbial protein synthesis (MPS) in Holstein steers. PMID:25049518

  12. Effects of Synchronization of Carbohydrate and Protein Supply in Total Mixed Ration with Korean Rice Wine Residue on Ruminal Fermentation, Nitrogen Metabolism and Microbial Protein Synthesis in Holstein Steers

    Directory of Open Access Journals (Sweden)

    Min Yu Piao

    2012-11-01

    Full Text Available Three Holstein steers in the growing phase, each with a ruminal cannula, were used to test the hypothesis that the synchronization of the hourly rate of carbohydrate and nitrogen (N released in the rumen would increase the amount of retained nitrogen for growth and thus improve the efficiency of microbial protein synthesis (EMPS. In Experiment 1, in situ degradability coefficients of carbohydrate and N in feeds including Korean rice wine residue (RWR were determined. In Experiment 2, three total mixed ration (TMR diets having different rates of carbohydrate and N release in the rumen were formulated using the in situ degradability of the feeds. All diets were made to contain similar contents of crude protein (CP and neutral detergent fiber (NDF but varied in their hourly pattern of nutrient release. The synchrony index of the three TMRs was 0.51 (LS, 0.77 (MS and 0.95 (HS, respectively. The diets were fed at a restricted level (2% of the animal’s body weight in a 3×3 Latin-square design. Synchronizing the hourly supply of energy and N in the rumen did not significantly alter the digestibility of dry matter, organic matter, crude protein, NDF or acid detergent fiber (ADF (p>0.05. The ruminal NH3-N content of the LS group at three hours after feeding was significantly higher (p0.05. In addition, the purine derivative (PD excretion in urine and microbial-N production (MN among the three groups were not significantly different (p>0.05. In conclusion, synchronizing dietary energy and N supply to the rumen did not have a major effect on nutrient digestion or microbial protein synthesis (MPS in Holstein steers.

  13. Fractionation of phosphorus added as a vegetal residue (32 P) and a fertilizer (32 P) between soil, plant and microbial biomass

    International Nuclear Information System (INIS)

    Pereira, M.C.

    1988-04-01

    Sugar cane straw and/or P-fertilizer phosphorus-32 labelled were added to a Red Yellow podzolic soil from Goiana-PE. The treated samples were used in a pot experiment, growing sorghum plants for 4 and 6 weeks, and in an incubation experiment with incubation periods of 1, 2, 3, 4 and 6 weeks without plants in order to follow the dynamics of the P added. After each harvest and incubation period the soil were analysed for 31 P and 32 P in the microbial biomass and in sequential extracts with resin (Pi), 0.5 M Na H Co 3 (Pi, Po) and 0.1 N NaOH (Pi, Po). The 31 P and 32 P contents of the sorghum in the pot experiment were also determined. (author)

  14. The Sensory Properties, Color, Microbial, Lipid Oxidation, and Residual Nitrite of Se’i Marinated with Lime and Roselle Calyces Extracts

    Directory of Open Access Journals (Sweden)

    G. E. M. Malelak

    2017-12-01

    Full Text Available Meat deterioration can occur because of lipid oxidation and bacteria that could affect meat quality. It has been recognized that fruits of lime (Citrus aurantifolia and roselle (Hibiscus sabdariffa calyces contain bioactive compounds that have a capability to prevent oxidation and bacterial growth. The objective of this research was to  investigate the effect of lime and roselle calyces extracts on se’i (Rotenese smoked beef quality. Completely randomized design (CRD with 2x4 factorial pattern was used in this study. The first factor (E was source of extracts i.e., lime extract (E1 and roselle extract (E2. The second factor (L was level of the extract consisted of 4 levels i.e., control (without extract/ L0; L1= 1%; L2= 2%; and L3= 3% (v/v. Each treatment consisted of 3 replications. Sensory properties measured were aroma, taste, and tenderness. Other variables measured were color, total plate count (TPC, thiobarbituric acid reactive substances (TBARS, and residual nitrite.  The taste and tenderness of se’i were affected (P<0.05 by combination of the extract and the level of the extract.  Results showed that there were significant interactions (P<0.05 between the kind of extracts and the level of extract on L (lightness, a (redness, and b (yellowness values, TPC, TBARS, and residual nitrite values. The level of 3% of  lime extract as well as 3% of roselle calyces extract improved score of taste and tenderness, reduced a values, decreased TPC, TBARS, and residual nitrite values. Marinating in 3% of roselle calyces extract decreased the b value but marinating in 3% of lime increased the b value of se’i. It is concluded that marinating 3% of roselle or 3% of lime gives the best effect on taste, tenderness, TPC, and TBARS values of se’i.

  15. Microbial degradation of 15N-labeled rice residues in soil during two years' incubation under flooded and upland conditions, (1)

    International Nuclear Information System (INIS)

    Kanazawa, Shinjiro; Yoneyama, Tadakatsu.

    1980-01-01

    The decay of rice residue was investigated after incubation periods of from 1 to 24 months at 30 0 C under both blooded and upland soil conditions. Tops and roots of rice plants were cut into about 10-mm length, and separately incorporated in soil which had been passed through a 0.5-mm sieve. Plant debris were fractionated physically according to their sizes and divided into five groups (> 4 mm, 4 - 2 mm, 2 - 1 mm, 1 - 0.5 mm, and 0.5 - 0.25 mm). Carbon loss from the soils amended with rice residues and decrease in the weight of total plant debris proceeded at a rapid speed in the early periods (around 4 months) and then at a slow speed in the subsequent periods under both flooded and upland soil conditions. The distribution of the plant debris in the decomposition processes differed under flooded and upland conditions. Under flooded conditions, 2 - 4 mm-sized plant debris were retained for a long period with slow transformation into the smaller fractions. In contrast, under upland conditions, change of plant debris from large to small size fractions proceeded gradually. This continuous change could be attributed to the high decomposing activities of fungi under upland conditions. (author)

  16. Decomposition rates and residue-colonizing microbial communities of Bacillus thuringiensis insecticidal protein Cry3Bb-expressing (Bt) and non-Bt corn hybrids in the field.

    Science.gov (United States)

    Xue, Kai; Serohijos, Raquel C; Devare, Medha; Thies, Janice E

    2011-02-01

    Despite the rapid adoption of crops expressing the insecticidal Cry protein(s) from Bacillus thuringiensis (Bt), public concern continues to mount over the potential environmental impacts. Reduced residue decomposition rates and increased tissue lignin concentrations reported for some Bt corn hybrids have been highlighted recently as they may influence soil carbon dynamics. We assessed the effects of MON863 Bt corn, producing the Cry3Bb protein against the corn rootworm complex, on these aspects and associated decomposer communities by terminal restriction fragment length polymorphism (T-RFLP) analysis. Litterbags containing cobs, roots, or stalks plus leaves from Bt and unmodified corn with (non-Bt+I) or without (non-Bt) insecticide applied were placed on the soil surface and at a 10-cm depth in field plots planted with these crop treatments. The litterbags were recovered and analyzed after 3.5, 15.5, and 25 months. No significant effect of treatment (Bt, non-Bt, and non-Bt+I) was observed on initial tissue lignin concentrations, litter decomposition rate, or bacterial decomposer communities. The effect of treatment on fungal decomposer communities was minor, with only 1 of 16 comparisons yielding separation by treatment. Environmental factors (litterbag recovery year, litterbag placement, and plot history) led to significant differences for most measured variables. Combined, these results indicate that the differences detected were driven primarily by environmental factors rather than by any differences between the corn hybrids or the use of tefluthrin. We conclude that the Cry3Bb corn tested in this study is unlikely to affect carbon residence time or turnover in soils receiving these crop residues.

  17. Analysis of a systematic search-based algorithm for determining protein backbone structure from a minimum number of residual dipolar couplings.

    Science.gov (United States)

    Wang, Lincong; Donald, Bruce Randall

    2004-01-01

    We have developed an ab initio algorithm for determining a protein backbone structure using global orientational restraints on internuclear vectors derived from residual dipolar couplings (RDCs) measured in one or two different aligning media by solution nuclear magnetic resonance (NMR) spectroscopy [14, 15]. Specifically, the conformation and global orientations of individual secondary structure elements are computed, independently, by an exact solution, systematic search-based minimization algorithm using only 2 RDCs per residue. The systematic search is built upon a quartic equation for computing, exactly and in constant time, the directions of an internuclear vector from RDCs, and linear or quadratic equations for computing the sines and cosines of backbone dihedral (phi, psi) angles from two vectors in consecutive peptide planes. In contrast to heuristic search such as simulated annealing (SA) or Monte-Carlo (MC) used by other NMR structure determination algorithms, our minimization algorithm can be analyzed rigorously in terms of expected algorithmic complexity and the coordinate precision of the protein structure as a function of error in the input data. The algorithm has been successfully applied to compute the backbone structures of three proteins using real NMR data.

  18. Microbial effects

    International Nuclear Information System (INIS)

    Sharpe, V.J.

    1985-10-01

    The long term safety and integrity of radioactive waste disposal sites proposed for use by Ontario Hydro may be affected by the release of radioactive gases. Microbes mediate the primary pathways of waste degradation and hence an assessment of their potential to produce gaseous end products from the breakdown of low level waste was performed. Due to a number of unknown variables, assumptions were made regarding environmental and waste conditions that controlled microbial activity; however, it was concluded that 14 C and 3 H would be produced, albeit over a long time scale of about 1500 years for 14 C in the worst case situation

  19. Atividade microbiana em solos, influenciada por resíduos de algodão e torta de mamona Microbial activity in soils influenced by residues of cotton and castor bean presscake

    Directory of Open Access Journals (Sweden)

    Silvia Capuani

    2012-12-01

    Full Text Available A atividade microbiana não se constitui apenas como bom indicador da qualidade do solo, mas é influenciada pela adição de carbono no sistema, o qual serve como substrato aos micro-organismos que aumentam sua atividade e a liberação de CO2, compreendendo a respiração edáfica do solo. Objetivou-se, neste trabalho, avaliar a atividade microbiana em diferentes tipos de solo com a adição de torta de mamona e resíduo têxtil de algodão. O trabalho foi conduzido em casa de vegetação na sede da Embrapa Algodão, em delineamento de blocos casualisados em esquema fatorial 4 x 3, com quatro repetições. A intervalos predeterminados de 4 dias os recipientes foram abertos e a solução de NaOH foi titulada com HCl 2 N na presença de indicador ácido/base fenolftaleína. Após a leitura a mesma quantidade de NaOH foi reposta e os recipientes novamente fechados. A diferença entre a quantidade de ácido necessária para neutralizar o hidróxido de sódio no recipiente testemunha e nos tratamentos equivale à quantidade de gás carbônico produzido pelos micro-organismos do solo. Constatou-se que os resíduos influenciaram significativamente a atividade microbiana nos diferentes tipos de solo, sobretudo nas primeiras determinações, apresentando-se como boas fontes para mineralização e fornecimento de nutrientes, tendo a torta de mamona proporcionado maior liberação acumulada de CO2 pelos micro-organismos.Microbial activity constitutes a good indicator of soil quality, and is influenced by the addition of carbon in the system serving as a substrate for microorganisms that increase their activity and release of CO2, comprising the edaphic respiration of the soil. The objective of this study was to evaluate the microbial activity in different soil types with the addition of cake press of castor bean and cotton textile residue. The study was conducted in a greenhouse at the headquarters of Embrapa Cotton in randomized block design in 4 x 3

  20. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria.

    Science.gov (United States)

    Negassa, Wakene C; Guber, Andrey K; Kravchenko, Alexandra N; Marsh, Terence L; Hildebrandt, Britton; Rivers, Mark L

    2015-01-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO2 emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S-18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75-80% of the added plant residue was decomposed, cumulative CO2 emission constituted 1,200 µm C g(-1) soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO2 emission constituted 2,000 µm C g(-1) soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO2 emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of soil C

  1. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria.

    Directory of Open Access Journals (Sweden)

    Wakene C Negassa

    Full Text Available Physical protection of soil carbon (C is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i decomposition of added plant residue, (ii CO2 emission from soil, and (iii structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S-18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm pores, 75-80% of the added plant residue was decomposed, cumulative CO2 emission constituted 1,200 µm C g(-1 soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO2 emission constituted 2,000 µm C g(-1 soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO2 emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of

  2. Properties of Soil Pore Space Regulate Pathways of Plant Residue Decomposition and Community Structure of Associated Bacteria

    Science.gov (United States)

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-01-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO2 emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO2 emission constituted 1,200 µm C g-1 soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO2 emission constituted 2,000 µm C g-1 soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO2 emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of soil C

  3. In-field rates of decomposition and microbial communities colonizing residues vary by depth of residue placement and plant part, but not by crop genotype for residues from two Cry1AB Bt corn hybrids and their non-transgenic i

    Science.gov (United States)

    The adoption of Bt corn has been largely overshadowed by concerns about their unintended effects on human health and the environment. Residues of transgenic Bt crops decomposed more slowly than their non-transgenic isolines in one laboratory study, although no mechanism to explain these observations...

  4. Nitrous oxide and N-leaching losses from agricultural soil: Influence of crop residue particle size, quality and placement

    DEFF Research Database (Denmark)

    Ambus, P.; Jensen, E.S.; Robertson, G.P.

    2001-01-01

    protection of the crop residue material against microbial attack. Leaching of N tended to be reduced about 40 % with barley and 20 % with pea, but the numbers were not significantly different from residue-free soil, which leached 4.7-4.9 g N m(-2). When wheat and alfalfa residues were mixed into the soil N2O...... emissions increased 6.5 and 1.6 times, respectively, compared with residue placed in a layer. Wheat residue in a layer evolved 3.4-times less N2O than alfalfa in a layer, whereas when mixed the two residue types evolved similar amounts of N2O. This difference was probably due to N-limitations in localised...

  5. Quadratic residues and non-residues selected topics

    CERN Document Server

    Wright, Steve

    2016-01-01

    This book offers an account of the classical theory of quadratic residues and non-residues with the goal of using that theory as a lens through which to view the development of some of the fundamental methods employed in modern elementary, algebraic, and analytic number theory. The first three chapters present some basic facts and the history of quadratic residues and non-residues and discuss various proofs of the Law of Quadratic Reciprosity in depth, with an emphasis on the six proofs that Gauss published. The remaining seven chapters explore some interesting applications of the Law of Quadratic Reciprocity, prove some results concerning the distribution and arithmetic structure of quadratic residues and non-residues, provide a detailed proof of Dirichlet’s Class-Number Formula, and discuss the question of whether quadratic residues are randomly distributed. The text is a valuable resource for graduate and advanced undergraduate students as well as for mathematicians interested in number theory.

  6. Residuation theory

    CERN Document Server

    Blyth, T S; Sneddon, I N; Stark, M

    1972-01-01

    Residuation Theory aims to contribute to literature in the field of ordered algebraic structures, especially on the subject of residual mappings. The book is divided into three chapters. Chapter 1 focuses on ordered sets; directed sets; semilattices; lattices; and complete lattices. Chapter 2 tackles Baer rings; Baer semigroups; Foulis semigroups; residual mappings; the notion of involution; and Boolean algebras. Chapter 3 covers residuated groupoids and semigroups; group homomorphic and isotone homomorphic Boolean images of ordered semigroups; Dubreil-Jacotin and Brouwer semigroups; and loli

  7. Effects of microbial stimulation on the number, size and activity of bronchus-associated lymphoid tissue (BALT) structures in the pig.

    OpenAIRE

    Delventhal, S.; Hensel, A.; Petzoldt, K.; Pabst, R.

    1992-01-01

    The development of bronchus-associated lymphoid tissue (BALT) was investigated in the pig, which is a species in which BALT is not found constantly. Different routes of contact with a specifically lung-pathogen bacterium Actinobacillus (Haemophilus) pleuropneumoniae were tested. Pigs, selected by bacteriological screening methods and the number of granulocytes in the bronchoalveolar lavage (BAL), were infected by aerosol. They were compared to previously enterally immunized pigs using active ...

  8. Soil microbial toxicity of eight polycyclic aromatic compounds: effects on nitrification, the genetic diversity of bacteria, and the total number of protozoans

    DEFF Research Database (Denmark)

    Sverdrup, Line Emilie; Ekelund, Flemming; Krogh, Paul Henning

    2002-01-01

    Eight polycyclic aromatic compounds (PACs) were tested for their toxic effect on the soil nitrification process, bacterial genetic diversity, and the total number of protozoans (naked amoebae and heterotrophic flagellates). After four weeks of exposure in a well-characterized agricultural soil......, toxic effects were evaluated by comparison to uncontaminated control soils. All PACs affected the nitrification process, and the calculated no-observed-effect concentrations (NOECs) for nitrification were 79 mg/kg for pyrene, 24 mg/kg for fluoranthene, 26 mg/kg for phenanthrene, 72 mg/kg for fluorene......, 23 mg/kg for carbazole, 22 mg/kg for dibenzothiophene, 75 mg/kg for dibenzofuran, and 1,100 mg/kg for acridine. For all substances but acridine, nitrification was the most sensitive of the three toxicity indicators evaluated. No effect of the tested substances on bacterial diversity was found...

  9. Soil microbial toxicity of eight polycyclic aromatic compounds: effects on nitrification, the genetic diversity of bacteria, and the total number of protozoans

    DEFF Research Database (Denmark)

    Sverdrup, Line Emilie; Ekelund, Flemming; Krogh, Paul Henning

    2002-01-01

    Eight polycyclic aromatic compounds (PACs) were tested for their toxic effect on the soil nitrification process, bacterial genetic diversity, and the total number of protozoans (naked amoebae and heterotrophic flagellates). After four weeks of exposure in a well-characterized agricultural soil......, toxic effects were evaluated by comparison to uncontaminated control soils. All PACs affected the nitrification process, and the calculated no-observed-effect concentrations (NOECs) for nitrification were 79 mg/kg for pyrene, 24 mg/kg for fluoranthene, 26 mg/kg for phenanthrene, 72 mg/kg for fluorene...... mg/kg. For effects on nitrification, toxicity (NOEC values) expressed as soil pore-water concentrations (log10(micromol/L)) showed a significant inverse relationship with lipophilicity (log octanol-water partition coefficient) of the substances (r2 = 0.69, p = 0.011, n = 8). This finding could...

  10. Residue processing

    Energy Technology Data Exchange (ETDEWEB)

    Gieg, W.; Rank, V.

    1942-10-15

    In the first stage of coal hydrogenation, the liquid phase, light and heavy oils were produced; the latter containing the nonliquefied parts of the coal, the coal ash, and the catalyst substances. It was the problem of residue processing to extract from these so-called let-down oils that which could be used as pasting oils for the coal. The object was to obtain a maximum oil extraction and a complete removal of the solids, because of the latter were returned to the process they would needlessly burden the reaction space. Separation of solids in residue processing could be accomplished by filtration, centrifugation, extraction, distillation, or low-temperature carbonization (L.T.C.). Filtration or centrifugation was most suitable since a maximum oil yield could be expected from it, since only a small portion of the let-down oil contained in the filtration or centrifugation residue had to be thermally treated. The most satisfactory centrifuge at this time was the Laval, which delivered liquid centrifuge residue and centrifuge oil continuously. By comparison, the semi-continuous centrifuges delivered plastic residues which were difficult to handle. Various apparatus such as the spiral screw kiln and the ball kiln were used for low-temperature carbonization of centrifuge residues. Both were based on the idea of carbonization in thin layers. Efforts were also being made to produce electrode carbon and briquette binder as by-products of the liquid coal phase.

  11. Microbial pesticides

    Science.gov (United States)

    Michael L. McManus

    1991-01-01

    Interest in the use of microbial pesticides has intensified because of public concern about the safety of chemical pesticides and their impact in the environment. Characteristics of the five groups of entomopathogens that have potential as microbial pesticides are briefly discussed and an update is provided on research and development activities underway to enhance the...

  12. Residual risk

    African Journals Online (AJOL)

    ing the residual risk of transmission of HIV by blood transfusion. An epidemiological approach assumed that all HIV infections detected serologically in first-time donors were pre-existing or prevalent infections, and that all infections detected in repeat blood donors were new or incident infections. During 1986 - 1987,0,012%.

  13. Weld Residual Stress in Corner Boxing Joints

    OpenAIRE

    Kazuyoshi, Matsuoka; Tokuharu, Yoshii; Ship Research Institute, Ministry of Transport; Ship Research Institute, Ministry of Transport

    1998-01-01

    Fatigue damage often occurs in corner boxing welded joints because of stress concentration and residual stress. The hot spot stress approach is applicable to stress concentration. However, the number of suitable methods for estimating residual stress in welded joints is limited. The purpose of this paper is to clarify the residual stress in corner boxing joints. The method of estimating residual stresses based on the inherent stress technique is presented. Residual stress measurements are per...

  14. Sequential enrichment of microbial population exhibiting enhanced biodegradation of crude oil

    International Nuclear Information System (INIS)

    Venkateswaran, Kasthuri; Harayama, Shigeaki.

    1995-01-01

    The distribution of oil-degrading bacteria in the coastal waters and sediments of Hokkaido, Japan, was surveyed. It was found that the potential of mixed microbial populations to degrade weathered crude oil was not confined to any ecological components (water or sediment) nor to the sampling stations. One microbial culture that was stable during repeated subculturing degraded 45% of the saturates and 20% of the aromatics present in crude oil in 10 days during the initial screening. The residual hydrocarbons in this culture were extracted by chloroform and dispersed in a fresh seawater-based medium and subsequently inoculated with microorganisms from the first culture. After full growth of the second culture, the residual hydrocarbons were extracted and dispersed in a fresh medium in which microorganisms from the second culture had been inoculated. This sequential process was carried out six times to enrich those microorganisms that grew on the recalcitrant components of crude oil. After repeated exposure of the residual crude oil to the enriched microorganisms, about 80% of the initially added crude oil was degraded. The cultures obtained after each enrichment cycle were kept, and the degradation of fresh crude oil by the enriched microorganisms was monitored. The degrading activity of the enriched cultures increased as the number of enrichment cycles increased. A microbial population that had been selected six times on the residual crude oil could degrade 70% of the saturates and 30% of the aromatics of crude oil, indicating that growth of a microbial population on residual crude oil improved its ability to biodegrade crude oil. 21 refs., 2 tabs., 7 figs

  15. Corn residue removal and CO2 emissions

    Science.gov (United States)

    Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) are the primary greenhouse gases (GHG) emitted from the soil due to agricultural activities. In the short-term, increases in CO2 emissions indicate increased soil microbial activity. Soil micro-organisms decompose crop residues and release...

  16. RESIDUAL RISK ASSESSMENTS - RESIDUAL RISK ...

    Science.gov (United States)

    This source category previously subjected to a technology-based standard will be examined to determine if health or ecological risks are significant enough to warrant further regulation for Coke Ovens. These assesments utilize existing models and data bases to examine the multi-media and multi-pollutant impacts of air toxics emissions on human health and the environment. Details on the assessment process and methodologies can be found in EPA's Residual Risk Report to Congress issued in March of 1999 (see web site). To assess the health risks imposed by air toxics emissions from Coke Ovens to determine if control technology standards previously established are adequately protecting public health.

  17. Changes in Rumen Microbial Community Composition during Adaption to an In Vitro System and the Impact of Different Forages.

    Directory of Open Access Journals (Sweden)

    Melanie B Lengowski

    Full Text Available This study examined ruminal microbial community composition alterations during initial adaption to and following incubation in a rumen simulation system (Rusitec using grass or corn silage as substrates. Samples were collected from fermenter liquids at 0, 2, 4, 12, 24, and 48 h and from feed residues at 0, 24, and 48 h after initiation of incubation (period 1 and on day 13 (period 2. Microbial DNA was extracted and real-time qPCR was used to quantify differences in the abundance of protozoa, methanogens, total bacteria, Fibrobacter succinogenes, Ruminococcus albus, Ruminobacter amylophilus, Prevotella bryantii, Selenomonas ruminantium, and Clostridium aminophilum. We found that forage source and sampling time significantly influenced the ruminal microbial community. The gene copy numbers of most microbial species (except C. aminophilum decreased in period 1; however, adaption continued through period 2 for several species. The addition of fresh substrate in period 2 led to increasing copy numbers of all microbial species during the first 2-4 h in the fermenter liquid except protozoa, which showed a postprandial decrease. Corn silage enhanced the growth of R. amylophilus and F. succinogenes, and grass silage enhanced R. albus, P. bryantii, and C. aminophilum. No effect of forage source was detected on total bacteria, protozoa, S. ruminantium, or methanogens or on total gas production, although grass silage enhanced methane production. This study showed that the Rusitec provides a stable system after an adaption phase that should last longer than 48 h, and that the forage source influenced several microbial species.

  18. Changes in Rumen Microbial Community Composition during Adaption to an In Vitro System and the Impact of Different Forages.

    Science.gov (United States)

    Lengowski, Melanie B; Zuber, Karin H R; Witzig, Maren; Möhring, Jens; Boguhn, Jeannette; Rodehutscord, Markus

    2016-01-01

    This study examined ruminal microbial community composition alterations during initial adaption to and following incubation in a rumen simulation system (Rusitec) using grass or corn silage as substrates. Samples were collected from fermenter liquids at 0, 2, 4, 12, 24, and 48 h and from feed residues at 0, 24, and 48 h after initiation of incubation (period 1) and on day 13 (period 2). Microbial DNA was extracted and real-time qPCR was used to quantify differences in the abundance of protozoa, methanogens, total bacteria, Fibrobacter succinogenes, Ruminococcus albus, Ruminobacter amylophilus, Prevotella bryantii, Selenomonas ruminantium, and Clostridium aminophilum. We found that forage source and sampling time significantly influenced the ruminal microbial community. The gene copy numbers of most microbial species (except C. aminophilum) decreased in period 1; however, adaption continued through period 2 for several species. The addition of fresh substrate in period 2 led to increasing copy numbers of all microbial species during the first 2-4 h in the fermenter liquid except protozoa, which showed a postprandial decrease. Corn silage enhanced the growth of R. amylophilus and F. succinogenes, and grass silage enhanced R. albus, P. bryantii, and C. aminophilum. No effect of forage source was detected on total bacteria, protozoa, S. ruminantium, or methanogens or on total gas production, although grass silage enhanced methane production. This study showed that the Rusitec provides a stable system after an adaption phase that should last longer than 48 h, and that the forage source influenced several microbial species.

  19. Microbial Monitoring of the International Space Station

    Science.gov (United States)

    Pierson, Duane L.; Botkin, Douglas J.; Bruce, Rebekah J.; Castro, Victoria A.; Smith, Melanie J.; Oubre, Cherie M.; Ott, C. Mark

    2013-01-01

    microbial growth. Air filtration can dramatically reduce the number of airborne bacteria, fungi, and particulates in spacecraft breathing air. Waterborne bacteria can be reduced to acceptable levels by thermal inactivation of bacteria during water processing, along with a residual biocide, and filtration at the point of use can ensure safety. System design must include onboard capability to achieve recovery of the system from contamination. Robust housekeeping procedures that include periodic cleaning and disinfection will prevent high levels of microbial growth on surfaces. Food for consumption in space must be thoroughly tested for excessive microbial content and pathogens before launch. Thorough preflight examination of flight crews, consumables, payloads, and the environment can greatly reduce pathogens in spacecraft. Many of the lessons learned from the Space Shuttle and previous programs were applied in the early design phase of the International Space Station, resulting in the safest space habitat to date. This presentation describes the monitoring program for the International Space Station and will summarize results from preflight and on-orbit monitoring.

  20. Residual nilpotence and residual solubility of groups

    International Nuclear Information System (INIS)

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  1. Microbial Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, Merry [American Society for Microbiology (ASM), Washington, DC (United States); Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2006-10-01

    The American Academy of Microbiology convened a colloquium March 10-12, 2006, in San Francisco, California, to discuss the production of energy fuels by microbial conversions. The status of research into various microbial energy technologies, the advantages and disadvantages of each of these approaches, research needs in the field, and education and training issues were examined, with the goal of identifying routes for producing biofuels that would both decrease the need for fossil fuels and reduce greenhouse gas emissions. Currently, the choices for providing energy are limited. Policy makers and the research community must begin to pursue a broader array of potential energy technologies. A diverse energy portfolio that includes an assortment of microbial energy choices will allow communities and consumers to select the best energy solution for their own particular needs. Funding agencies and governments alike need to prepare for future energy needs by investing both in the microbial energy technologies that work today and in the untested technologies that will serve the world’s needs tomorrow. More mature bioprocesses, such as ethanol production from starchy materials and methane from waste digestors, will find applications in the short term. However, innovative techniques for liquid fuel or biohydrogen production are among the longer term possibilities that should also be vigorously explored, starting now. Microorganisms can help meet human energy needs in any of a number of ways. In their most obvious role in energy conversion, microorganisms can generate fuels, including ethanol, hydrogen, methane, lipids, and butanol, which can be burned to produce energy. Alternatively, bacteria can be put to use in microbial fuel cells, where they carry out the direct conversion of biomass into electricity. Microorganisms may also be used some day to make oil and natural gas technologies more efficient by sequestering carbon or by assisting in the recovery of oil and

  2. Dynamics of culturable soil microbial communities during ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-20

    Oct 20, 2008 ... Dynamics of culturable soil microbial communities during decomposition of some ... semi-arid and arid agroecozones of West Africa to measure the dynamics of culturable bacterial and fungal communities in the ... fauna activities, depending on the chemical composition of the residue; C/N ratio, lignin and ...

  3. Automatic prediction of catalytic residues by modeling residue structural neighborhood

    Directory of Open Access Journals (Sweden)

    Passerini Andrea

    2010-03-01

    Full Text Available Abstract Background Prediction of catalytic residues is a major step in characterizing the function of enzymes. In its simpler formulation, the problem can be cast into a binary classification task at the residue level, by predicting whether the residue is directly involved in the catalytic process. The task is quite hard also when structural information is available, due to the rather wide range of roles a functional residue can play and to the large imbalance between the number of catalytic and non-catalytic residues. Results We developed an effective representation of structural information by modeling spherical regions around candidate residues, and extracting statistics on the properties of their content such as physico-chemical properties, atomic density, flexibility, presence of water molecules. We trained an SVM classifier combining our features with sequence-based information and previously developed 3D features, and compared its performance with the most recent state-of-the-art approaches on different benchmark datasets. We further analyzed the discriminant power of the information provided by the presence of heterogens in the residue neighborhood. Conclusions Our structure-based method achieves consistent improvements on all tested datasets over both sequence-based and structure-based state-of-the-art approaches. Structural neighborhood information is shown to be responsible for such results, and predicting the presence of nearby heterogens seems to be a promising direction for further improvements.

  4. Distribution of residues and primitive roots

    Indian Academy of Sciences (India)

    quadratic residues and non-residues cases using some refinement of van der Warden's the- orem in combinatorial number theory. Therefore, in his proof, the constant p0(N) depends on the van der Warden number, which is very difficult to calculate for all N. For instance, recently, Luca and Thangadurai [8] proved that for all ...

  5. Microbial Ecosystems, Protection of

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Nelson, K.E.

    2014-01-01

    Synonyms Conservation of microbial diversity and ecosystem functions provided by microbes; Preservation of microbial diversity and ecosystem functions provided by microbes Definition The use, management, and conservation of ecosystems in order to preserve microbial diversity and functioning.

  6. Avaliação da qualidade nutricional da silagem de cana-de-açúcar com aditivos microbianos e enriquecida com resíduo da colheita de soja Evaluation of the nutritional quality of sugarcane silage treated with microbial additives and soybean crop residue

    Directory of Open Access Journals (Sweden)

    Acyr Wanderley de Paula Freitas

    2006-02-01

    Full Text Available Objetivou-se avaliar as características fermentativas e a qualidade nutricional da silagem de cana-de-açúcar tratada com aditivos microbianos e enriquecida com 10% de resíduo da colheita de soja, com base no peso verde da cana. O experimento foi conduzido em delineamento inteiramente ao acaso, com três repetições, utilizando-se a variedade RB855536, colhida em soca aos 16 meses. Embora a adição do resíduo da colheita de soja tenha promovido aumento do pH final da silagem, os tratamentos com resíduo diminuíram em 33% as perdas de matéria seca das silagens e em 60% o teor de N-amoniacal em relação ao nitrogênio total. A adição dos inoculantes reduziu o pH da silagem quando em associação ao resíduo de soja, não exercendo efeito significativo sobre os outros parâmetros estudados. Em todos os tratamentos, as silagens apresentaram maiores concentrações dos componentes da fibra e redução nos teores de MS em relação ao material original, antes da ensilagem. Nos tratamentos com resíduo, os valores de digestibilidade in vitro da matéria seca (DIVMS foram superiores aos obtidos nos demais tratamentos. Quando comparado o material utilizado para ensilagem, a redução na digestibilidade foi superior para os tratamentos sem o resíduo (24,3 vs 9,3%. A associação do resíduo da colheita de soja à cana-de-açúcar para ensilagem proporcionou melhor qualidade nutritiva, com menores perdas de MS e carboidratos solúveis, principalmente na forma de gases, e, conseqüentemente, menor acúmulo dos componentes da parede celular, além de redução na DIVMS da forragem. Não se recomenda a utilização dos inoculantes L. plantarum e L. buchneri na ensilagem da cana-de-açúcar, pois nenhuma melhoria foi observada na composição química ou no perfil de fermentação das silagens.The objective of this trial was to evaluate the fermentative characteristics and nutritional quality of sugarcane treated with microbial additives and 10% of

  7. HAMAP: a database of completely sequenced microbial proteome sets and manually curated microbial protein families in UniProtKB/Swiss-Prot.

    Science.gov (United States)

    Lima, Tania; Auchincloss, Andrea H; Coudert, Elisabeth; Keller, Guillaume; Michoud, Karine; Rivoire, Catherine; Bulliard, Virginie; de Castro, Edouard; Lachaize, Corinne; Baratin, Delphine; Phan, Isabelle; Bougueleret, Lydie; Bairoch, Amos

    2009-01-01

    The growth in the number of completely sequenced microbial genomes (bacterial and archaeal) has generated a need for a procedure that provides UniProtKB/Swiss-Prot-quality annotation to as many protein sequences as possible. We have devised a semi-automated system, HAMAP (High-quality Automated and Manual Annotation of microbial Proteomes), that uses manually built annotation templates for protein families to propagate annotation to all members of manually defined protein families, using very strict criteria. The HAMAP system is composed of two databases, the proteome database and the family database, and of an automatic annotation pipeline. The proteome database comprises biological and sequence information for each completely sequenced microbial proteome, and it offers several tools for CDS searches, BLAST options and retrieval of specific sets of proteins. The family database currently comprises more than 1500 manually curated protein families and their annotation templates that are used to annotate proteins that belong to one of the HAMAP families. On the HAMAP website, individual sequences as well as whole genomes can be scanned against all HAMAP families. The system provides warnings for the absence of conserved amino acid residues, unusual sequence length, etc. Thanks to the implementation of HAMAP, more than 200,000 microbial proteins have been fully annotated in UniProtKB/Swiss-Prot (HAMAP website: http://www.expasy.org/sprot/hamap).

  8. Nitrogen immobilization and mineralization during initial decomposition of 15N-labelled pea and barley residues

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1997-01-01

    The immobilization and mineralization of N following plant residue incorporation were studied in a sandy loam soil using N-15-labelled field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.) straw. Both crop residues caused a net immobilization of soil-derived inorganic N during...... the complete incubation period of 84 days. The maximum rate of N immobilization was found to 12 and 18 mg soil-derived N g(-1) added C after incorporation of pea and barley residues, respectively. After 7 days of incubation, 21% of the pea and 17% of the barley residue N were assimilated by the soil microbial...... the decomposition of the barley residue. The net mineralization of residue-derived N was 2% in the barley and 22% in the pea residue treatment after 84 days of incubation. The results demonstrated that even if crop residues have a relative low C/N ratio (15), transient immobilization of soil N in the microbial...

  9. Detection and identification of previously unrecognized microbial pathogens.

    OpenAIRE

    Relman, D. A.

    1998-01-01

    Features of a number of important but poorly explained human clinical syndromes strongly indicate a microbial etiology. In these syndromes, the failure of cultivation-dependent microbial detection methods reveals our ignorance of microbial growth requirements. Sequence-based molecular methods, however, offer alternative approaches for microbial identification directly from host specimens found in the setting of unexplained acute illnesses, chronic inflammatory disease, and from anatomic sites...

  10. Fundamentals of number theory

    CERN Document Server

    LeVeque, William J

    1996-01-01

    This excellent textbook introduces the basics of number theory, incorporating the language of abstract algebra. A knowledge of such algebraic concepts as group, ring, field, and domain is not assumed, however; all terms are defined and examples are given - making the book self-contained in this respect.The author begins with an introductory chapter on number theory and its early history. Subsequent chapters deal with unique factorization and the GCD, quadratic residues, number-theoretic functions and the distribution of primes, sums of squares, quadratic equations and quadratic fields, diopha

  11. Microbial bioconversion of pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Golovleva, L.A.; Aliyeva, R.M.; Naumova, R.P.; Gvozdyak, P.I. (Institute of Biochemistry and Physiology of Microorganisms, USSR Academy of Sciences, Moscow (USSR))

    1992-01-01

    Microorganisms totally detoxicate xenobiotics of various chemical structures, which are serious and, in some cases, very hazardous pollutants. At present, the efforts of a number of researchers promoted the establishment in this country of a collection of microorganisms able to degrade volatile toxic pollutants--toluene, isomeric xylenes, styrene, alpha-methylstyrene, crotonaldehyde; widely distributed xenobiotics chlorobenzoic acids; isomeric aryldicarboxylic acids; and ecologically hazardous pollutants such as aromatic nitrocompounds. The active strains-destructors are mainly representatives of the genera Pseudomonas and Rhodococcus. Research into their physiological characteristics, key enzymes, pathways of xenobiotics degradation, genetic mechanisms determining the degradation of these foreign compounds, and behaviour of the strains in a real environment made it possible to develop the theoretical principles of using these microbial cultures to purify real industrial wastes and remediate polluted areas of soil and water. Improvement of the methods of immobilizing the active xenobiotics-degrading strains on cheap and efficient carriers made it possible to significantly intensify the cleanup process of industrial wastes and eliminate a number of problems during the development of the biotechnologies for industrial waste cleanup. Successfully operated at present are the biotechnologies of the local cleanup of waste waters of terephthalate production, microbial purification of industrial waste waters in nylon-66 production from hexamethylenediamine, purification of coke production wastes from phenols, waste waters of polyisocyanate production from aromatic amines, local purification of waste waters in synthetic rubber production from alpha-methylstyrene, acetaldehyde production wastes from crotonaldehyde and mercury. 97 references.

  12. Microbial Observatory (ISS-MO): Microbial diversity

    Data.gov (United States)

    National Aeronautics and Space Administration — The environmental microbiome study was designed to decipher microbial diversity of the International Space Station surfaces in terms of spatial and temporal...

  13. Microbial carbon sources in boreal wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Daly, C.A.; Ciborowski, J.J.H. [Windsor Univ., ON (Canada). Dept. of Biology

    2004-07-01

    The role of heterotrophic microbial producers in decomposing organic matter was discussed along with the source supporting them and their role at the base of the aquatic food chain in boreal wetlands. The importance of diverse sources of carbon to microbial production was evaluated using stable isotope analysis. Carbon sources include wetland detritus, phytoplankton and anthropogenic sources of organic matter. Constructed wetlands have been proposed as a remediation strategy following oil sands processing in the Athabasca oil sands area. This study examined the extent to which residual bitumen in young oil sands-affected wetlands can be used as a carbon source that forms the base of the food chain in naturally formed wetlands. Stable isotope analyses was used to estimate the contribution of different carbon sources to microbial biomass. Planktonic and benthic microbial biomass and production was also estimated along with respiration losses in wetlands of contrasting ages and depositional histories. Although the rate of microbial biomass and production demonstrate how much carbon may be available to higher trophic levels, it is not fully understood how microbial production becomes assigned as detrital material, as a food source for zooplankton and zoobenthic communities, and as carbon respiration loss to the atmosphere. These 3 categories have important implications for boreal wetland reclamation strategies.

  14. Sagan numbers

    OpenAIRE

    Mendonça, J. Ricardo G.

    2012-01-01

    We define a new class of numbers based on the first occurrence of certain patterns of zeros and ones in the expansion of irracional numbers in a given basis and call them Sagan numbers, since they were first mentioned, in a special case, by the North-american astronomer Carl E. Sagan in his science-fiction novel "Contact." Sagan numbers hold connections with a wealth of mathematical ideas. We describe some properties of the newly defined numbers and indicate directions for further amusement.

  15. Fibonacci numbers

    CERN Document Server

    Vorob'ev, Nikolai Nikolaevich

    2011-01-01

    Fibonacci numbers date back to an 800-year-old problem concerning the number of offspring born in a single year to a pair of rabbits. This book offers the solution and explores the occurrence of Fibonacci numbers in number theory, continued fractions, and geometry. A discussion of the ""golden section"" rectangle, in which the lengths of the sides can be expressed as a ration of two successive Fibonacci numbers, draws upon attempts by ancient and medieval thinkers to base aesthetic and philosophical principles on the beauty of these figures. Recreational readers as well as students and teacher

  16. Number names and number understanding

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye; Misfeldt, Morten

    2014-01-01

    through using mathematical names for the numbers such as one-ten-one for 11 and five-ten-six for 56. The project combines the renaming of numbers with supporting the teaching with the new number names. Our hypothesis is that Danish children have more difficulties learning and working with numbers, because...... the Danish number names are more complicated than in other languages. Keywords: A research project in grade 0 and 1th in a Danish school, Base-10 system, two-digit number names, semiotic, cognitive perspectives....

  17. Linking microbial carbon utilization with microbially-derived soil organic matter

    Science.gov (United States)

    Kallenbach, Cynthia M.; Grandy, A. Stuart

    2014-05-01

    Soil microbial communities are fundamental to plant C turnover, as all C inputs eventually pass through the microbial biomass. In turn, there is increasing evidence that this biomass accumulates as a significant portion of stable soil organic matter (SOM) via physiochemical interactions with the soil matrix. However, when exploring SOM dynamics, these two processes are often regarded as discrete from one another, despite potentially important linkages between microbial C utilization and the fate of that biomass C as SOM. Specifically, if stable SOM is largely comprised of microbial products, we need to better understand the soil C inputs that influence microbial biomass production and microbial C allocation. Microbial physiology, such as microbial growth efficiency (MGE), growth rate and turnover have direct influences on microbial biomass production and are highly sensitive to resource quality. Therefore, the importance of resource quality on SOM accumulation may not necessarily be a function of resistance to decay but the degree to which it optimizes microbial biomass production. To examine the relationship between microbial C utilization and microbial contributions to SOM, an ongoing 15-mo incubation experiment was set up using artificial, initially C- and microbial-free soils. Soil microcosms were constructed by mixing sand with either kaolinite or montmorillonite clays followed with a natural soil microbial inoculum. For both soil mineral treatments, weekly additions of glucose, cellobiose, or syringol are carried out, with an additional treatment of plant leachate to serve as a reference. This simplified system allows us to determine 1) if, in absence of plant-derived C, chemically complex SOM similar to natural soils can accumulate through the production of microbial residues and 2) how differences in C utilization of simple substrates, varying in energy yields, influence the quantity and chemistry of newly formed SOM. Over the course of the incubation, MGE

  18. Microfluidics and microbial engineering.

    Science.gov (United States)

    Kou, Songzi; Cheng, Danhui; Sun, Fei; Hsing, I-Ming

    2016-02-07

    The combination of microbial engineering and microfluidics is synergistic in nature. For example, microfluidics is benefiting from the outcome of microbial engineering and many reported point-of-care microfluidic devices employ engineered microbes as functional parts for the microsystems. In addition, microbial engineering is facilitated by various microfluidic techniques, due to their inherent strength in high-throughput screening and miniaturization. In this review article, we firstly examine the applications of engineered microbes for toxicity detection, biosensing, and motion generation in microfluidic platforms. Secondly, we look into how microfluidic technologies facilitate the upstream and downstream processes of microbial engineering, including DNA recombination, transformation, target microbe selection, mutant characterization, and microbial function analysis. Thirdly, we highlight an emerging concept in microbial engineering, namely, microbial consortium engineering, where the behavior of a multicultural microbial community rather than that of a single cell/species is delineated. Integrating the disciplines of microfluidics and microbial engineering opens up many new opportunities, for example in diagnostics, engineering of microbial motors, development of portable devices for genetics, high throughput characterization of genetic mutants, isolation and identification of rare/unculturable microbial species, single-cell analysis with high spatio-temporal resolution, and exploration of natural microbial communities.

  19. Eulerian numbers

    CERN Document Server

    Petersen, T Kyle

    2015-01-01

    This text presents the Eulerian numbers in the context of modern enumerative, algebraic, and geometric combinatorics. The book first studies Eulerian numbers from a purely combinatorial point of view, then embarks on a tour of how these numbers arise in the study of hyperplane arrangements, polytopes, and simplicial complexes. Some topics include a thorough discussion of gamma-nonnegativity and real-rootedness for Eulerian polynomials, as well as the weak order and the shard intersection order of the symmetric group. The book also includes a parallel story of Catalan combinatorics, wherein the Eulerian numbers are replaced with Narayana numbers. Again there is a progression from combinatorics to geometry, including discussion of the associahedron and the lattice of noncrossing partitions. The final chapters discuss how both the Eulerian and Narayana numbers have analogues in any finite Coxeter group, with many of the same enumerative and geometric properties. There are four supplemental chapters throughout, ...

  20. Microbial and plant ecology of a long-term TNT-contaminated site

    Energy Technology Data Exchange (ETDEWEB)

    Travis, Emma R. [Institute of Biomedical and Life Sciences, University of Glasgow, Bower Building, Glasgow G12 8QQ (United Kingdom)], E-mail: e.travis@bio.gla.ac.uk; Bruce, Neil C. [CNAP, Department of Biology, University of York, York YO10 5YW (United Kingdom)], E-mail: ncb5@york.ac.uk; Rosser, Susan J. [Institute of Biomedical and Life Sciences, University of Glasgow, Bower Building, Glasgow G12 8QQ (United Kingdom)], E-mail: s.rosser@bio.gla.ac.uk

    2008-05-15

    The contamination of the environment with explosive residues presents a serious ecological problem at sites across the world, with the highly toxic compound trinitrotoluene (TNT) the most widespread contaminant. This study examines the soil microbial community composition across a long-term TNT-contaminated site. It also investigates the extent of nitroaromatic contamination and its effect on vegetation. Concentrations of TNT and its metabolites varied across the site and this was observed to dramatically impact on the extent and diversity of the vegetation, with the most heavily contaminated area completely devoid of vegetation. Bryophytes were seen to be particularly sensitive to TNT contamination. The microbial population experienced both a reduction in culturable bacterial numbers and a shift in composition at the high concentrations of TNT. DGGE and community-level physiological profiling (CLPP) revealed a clear change in both the genetic and functional diversity of the soil when soil was contaminated with TNT. - Long-term contamination of soil with TNT reduces the extent and diversity of vegetation, decreases culturable bacterial numbers and shifts the microbial community composition.

  1. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments...... and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  2. Crop residues and agro-industrial by-products used in traditional ...

    African Journals Online (AJOL)

    The crop residues were grouped under cereal crop residues (3), root crop residues (5), legume crop residues (3), and fruit crop residues (3). All the sampled respondents kept livestock and depend on the natural pasture as the main source of feed for their animals. The mean stock number per farmer in this study was 14.0 ...

  3. Transfinite Numbers

    Indian Academy of Sciences (India)

    Transfinite Numbers. What is Infinity? S M Srivastava. In a series of revolutionary articles written during the last quarter of the nineteenth century, the great Ger- man mathematician Georg Cantor removed the age-old mistrust of infinity and created an exceptionally beau- tiful and useful theory of transfinite numbers. This is.

  4. Number theory

    CERN Document Server

    Andrews, George E

    1994-01-01

    Although mathematics majors are usually conversant with number theory by the time they have completed a course in abstract algebra, other undergraduates, especially those in education and the liberal arts, often need a more basic introduction to the topic.In this book the author solves the problem of maintaining the interest of students at both levels by offering a combinatorial approach to elementary number theory. In studying number theory from such a perspective, mathematics majors are spared repetition and provided with new insights, while other students benefit from the consequent simpl

  5. Residual gas analysis

    International Nuclear Information System (INIS)

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  6. Nice numbers

    CERN Document Server

    Barnes, John

    2016-01-01

    In this intriguing book, John Barnes takes us on a journey through aspects of numbers much as he took us on a geometrical journey in Gems of Geometry. Similarly originating from a series of lectures for adult students at Reading and Oxford University, this book touches a variety of amusing and fascinating topics regarding numbers and their uses both ancient and modern. The author intrigues and challenges his audience with both fundamental number topics such as prime numbers and cryptography, and themes of daily needs and pleasures such as counting one's assets, keeping track of time, and enjoying music. Puzzles and exercises at the end of each lecture offer additional inspiration, and numerous illustrations accompany the reader. Furthermore, a number of appendices provides in-depth insights into diverse topics such as Pascal’s triangle, the Rubik cube, Mersenne’s curious keyboards, and many others. A theme running through is the thought of what is our favourite number. Written in an engaging and witty sty...

  7. Analysis of the structural diversity of the microbial community in a ...

    African Journals Online (AJOL)

    Microbial populations in paper-mill water systems are usually enumerated using microbiological techniques such as plate counts and the most probable number technique. These conventional methods can only quantify a limited percentage of the microbial populations and the microbial numbers are, therefore, generally ...

  8. Number names and number understanding

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye; Misfeldt, Morten

    2014-01-01

    This paper concerns the results from the first year of a three-year research project involving the relationship between Danish number names and their corresponding digits in the canonical base 10 system. The project aims to develop a system to help the students’ understanding of the base 10 system...... the Danish number names are more complicated than in other languages. Keywords: A research project in grade 0 and 1th in a Danish school, Base-10 system, two-digit number names, semiotic, cognitive perspectives....

  9. Microbial Field Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1990-11-01

    This report covers progress made during the first year of the Microbial Field Pilot Study project. Information on reservoir ecology and characterization, facility and treatment design, core experiments, bacterial mobility, and mathematical modeling are addressed. To facilitate an understanding of the ecology of the target reservoir analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. A preliminary design of facilities for the operation of the field pilot test was prepared. In addition, procedures for facilities installation and for injection treatments are described. The Southeast Vassar Vertz Sand Unit (SEVVSU), the site of the proposed field pilot study, is described physically, historically, and geologically. The fields current status is presented and the ongoing reservoir simulation is discussed. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. Two possible mechanisms, relative permeability effects and changes in the capillary number, are discussed and related to four Berea core experiments' results. The experiments were conducted at reservoir temperature using SEVVSU oil, brine, and bacteria. The movement and activity of bacteria in porous media were investigated by monitoring the growth of bacteria in sandpack cores under no flow conditions. The rate of bacteria advancement through the cores was determined. A mathematical model of the MEOR process has been developed. The model is a three phase, seven species, one dimensional model. Finite difference methods are used for solution. Advection terms in balance equations are represented with a third- order upwind differencing scheme to reduce numerical dispersion and oscillations. The model is applied to a batch fermentation example. 52 refs., 26 figs., 21 tabs.

  10. Biodiversity and species competition regulate the resilience of microbial biofilm community

    DEFF Research Database (Denmark)

    Feng, Kai; Zhang, Zhaojing; Cai, Weiwei

    2017-01-01

    The relationship between biodiversity and ecosystem stability is poorly understood in microbial communities. Biofilm communities in small bioreactors called microbial electrolysis cells (MEC) contain moderate species numbers and easy tractable functional traits, thus providing an ideal platform f...

  11. Funny Numbers

    Directory of Open Access Journals (Sweden)

    Theodore M. Porter

    2012-12-01

    Full Text Available The struggle over cure rate measures in nineteenth-century asylums provides an exemplary instance of how, when used for official assessments of institutions, these numbers become sites of contestation. The evasion of goals and corruption of measures tends to make these numbers “funny” in the sense of becoming dis-honest, while the mismatch between boring, technical appearances and cunning backstage manipulations supplies dark humor. The dangers are evident in recent efforts to decentralize the functions of governments and corporations using incen-tives based on quantified targets.

  12. Contribution of microbial carbon to soil fractions: significance of diverse microbial group biochemistry

    Science.gov (United States)

    Throckmorton, H.; Bird, J. A.; Dane, L.; Firestone, M. K.; Horwath, W. R.

    2011-12-01

    The importance of diverse microbial groups to soil C maintenance is still a matter of debate. This study follows the turnover of 13C labeled nonliving residues from diverse microbial groups into soil physical fractions in situ in a temperate forest in California (CA) and a tropical forest in Puerto Rico (PR), during 5 sampling points per site- over a 3 and 2 year period, respectively. Microbial groups include fungi, actinomycetes, Gm(+) bacteria, and Gm(-) bacteria, isolated from CA and PR soils to obtain temperate and tropical isolates composited of 3-4 species per group. The selected density fractionation approach isolated: a "light fraction" (LF), non-mineral aggregate "occluded fraction" (OF), and a "mineral bound fraction" (MF). Pyrolysis gas chromatography mass spectrometry (Py-GC-MS) was employed to characterize microbial group isolates, whole soils, and fractions. Microbial isolates contained unique biochemical fingerprints: temperate and tropical fungi and tropical Gm(-) were characterized by a low abundance of phenol, benzene, and N-compounds compared with other microbial group isolates. Py-GC-MS revealed compositional differences among soil fractions at both sites, likely attributed to differences in the decomposition stage and C source material (ie. plant vs. microbial). For both sites, benzene and N-compounds were greatest in the MF; lignin and phenol compounds were greatest in the LF; and lipids were greatest in the OF. The trend for polysaccharides differed between sites, with the greatest concentration in the CA OF; and for PR with the lowest concentration in the OF, and similar concentrations in the LF and MF. SOM chemistry was most similar between sites in the LF, compared with the OF and MF, suggesting that differences in SOM chemistry between sites may be more attributed to differential decomposition processes than unique litter quality inputs. A substantial portion of microbial C moved from the LF into the OF, and the MF by the first sampling

  13. Agricultural pesticide residues

    International Nuclear Information System (INIS)

    Fuehr, F.

    1984-01-01

    The utilization of tracer techniques in the study of agricultural pesticide residues is reviewed under the following headings: lysimeter experiments, micro-ecosystems, translocation in soil, degradation of pesticides in soil, biological availability of soil-applied substances, bound residues in the soil, use of macro- and microautography, double and triple labelling, use of tracer labelling in animal experiments. (U.K.)

  14. Number Guessing

    Science.gov (United States)

    Sezin, Fatin

    2009-01-01

    It is instructive and interesting to find hidden numbers by using different positional numeration systems. Most of the present guessing techniques use the binary system expressed as less-than, greater-than or present-absent type information. This article describes how, by employing four cards having integers 1-64 written in different colours, one…

  15. Transfinite Numbers

    Indian Academy of Sciences (India)

    this is a characteristic difference between finite and infinite sets and created an immensely useful branch of mathematics based on this idea which had a great impact on the whole of mathe- matics. For example, the question of what is a number (finite or infinite) is almost a philosophical one. However Cantor's work turned it ...

  16. Transfinite Numbers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 3. Transfinite Numbers - What is Infinity? S M Srivastava. General Article Volume 2 Issue 3 March 1997 pp 58-68. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/002/03/0058-0068 ...

  17. Microbial electrosynthetic cells

    Energy Technology Data Exchange (ETDEWEB)

    May, Harold D.; Marshall, Christopher W.; Labelle, Edward V.

    2018-01-30

    Methods are provided for microbial electrosynthesis of H.sub.2 and organic compounds such as methane and acetate. Method of producing mature electrosynthetic microbial populations by continuous culture is also provided. Microbial populations produced in accordance with the embodiments as shown to efficiently synthesize H.sub.2, methane and acetate in the presence of CO.sub.2 and a voltage potential. The production of biodegradable and renewable plastics from electricity and carbon dioxide is also disclosed.

  18. The Cauchy method of residues

    CERN Document Server

    Mitrinović, Dragoslav S

    1993-01-01

    Volume 1, i. e. the monograph The Cauchy Method of Residues - Theory and Applications published by D. Reidel Publishing Company in 1984 is the only book that covers all known applications of the calculus of residues. They range from the theory of equations, theory of numbers, matrix analysis, evaluation of real definite integrals, summation of finite and infinite series, expansions of functions into infinite series and products, ordinary and partial differential equations, mathematical and theoretical physics, to the calculus of finite differences and difference equations. The appearance of Volume 1 was acknowledged by the mathematical community. Favourable reviews and many private communications encouraged the authors to continue their work, the result being the present book, Volume 2, a sequel to Volume 1. We mention that Volume 1 is a revised, extended and updated translation of the book Cauchyjev raeun ostataka sa primenama published in Serbian by Nau~na knjiga, Belgrade in 1978, whereas the greater part ...

  19. Influence of secondary water supply systems on microbial community structure and opportunistic pathogen gene markers.

    Science.gov (United States)

    Li, Huan; Li, Shang; Tang, Wei; Yang, Yang; Zhao, Jianfu; Xia, Siqing; Zhang, Weixian; Wang, Hong

    2018-06-01

    Secondary water supply systems (SWSSs) refer to the in-building infrastructures (e.g., water storage tanks) used to supply water pressure beyond the main distribution systems. The purpose of this study was to investigate the influence of SWSSs on microbial community structure and the occurrence of opportunistic pathogens, the latter of which are an emerging public health concern. Higher numbers of bacterial 16S rRNA genes, Legionella and mycobacterial gene markers were found in public building taps served by SWSSs relative to the mains, regardless of the flushing practice (P < 0.05). In residential buildings, genes of L. pneumomhila, Acanthamoeba and Vermamoeba vermiformis were primarily detected in tanks and taps compared to the mains. Long water retention time, warm temperature and loss of disinfectant residuals promoted microbial growth and colonization of potential pathogens in SWSSs. Varied levels of microbial community shifts were found in different types of SWSSs during water transportation from the distribution main to taps, highlighting the critical role of SWSSs in shaping the drinking water microbiota. Overall, the results provided insight to factors that might aid in controlling pathogen proliferation in real-world water systems using SWSSs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Paraquat Herbicide in Peat Soil: I. Its Effects on The Dynamics of Microbial Population

    Directory of Open Access Journals (Sweden)

    Sebastian Margino

    2000-12-01

    Full Text Available Paraquat has been used widely and periodically in peat soil. It is stable in acid environments, therefore its application in peat soil which represents an acid environment, might prolong its persistence. Liming treatment has known to reduce peat soil acidity. This research was conducted to study the effect of paraquat and liming treatments on the dynamics of microbial population in peat soil. Unlimed and limed peat soil were treated with paraquat to a final concentration of 20 ppm, and incubated for 2 months. Microbiological analysis, consisting of counting of bacterial, actinomycetes, and fungal population were done weekly. The changes of pH value and paraquat residue were also measured. The results showed that in unlimed peat soil, paraquat treatment did not influence microbial population. However, when paraquat was added into limed peat soil, the number of microbial population decreased; especially the population of bacteria. Liming treatment increased bacterial population and changed the population dynamics of actinomycetes. No significant difference of fungal population in peat soil treated with paraquat and lime. Additionally, there was no significant difference in paraquat resistance between limed and unlimed peat soil.

  1. Antimicrobial Materials for Advanced Microbial Control in Spacecraft Water Systems

    Science.gov (United States)

    Birmele, Michele; Caro, Janicce; Newsham, Gerard; Roberts, Michael; Morford, Megan; Wheeler, Ray

    2012-01-01

    Microbial detection, identification, and control are essential for the maintenance and preservation of spacecraft water systems. Requirements set by NASA put limitations on the energy, mass, materials, noise, cost, and crew time that can be devoted to microbial control. Efforts are being made to attain real-time detection and identification of microbial contamination in microgravity environments. Research for evaluating technologies for capability enhancement on-orbit is currently focused on the use of adenosine triphosphate (ATP) analysis for detection purposes and polymerase chain reaction (peR) for microbial identification. Additional research is being conducted on how to control for microbial contamination on a continual basis. Existing microbial control methods in spacecraft utilize iodine or ionic silver biocides, physical disinfection, and point-of-use sterilization filters. Although these methods are effective, they require re-dosing due to loss of efficacy, have low human toxicity thresholds, produce poor taste, and consume valuable mass and crew time. Thus, alternative methods for microbial control are needed. This project also explores ultraviolet light-emitting diodes (UV-LEDs), surface passivation methods for maintaining residual biocide levels, and several antimicrobial materials aimed at improving current microbial control techniques, as well as addressing other materials presently under analysis and future directions to be pursued.

  2. Analysis of phosphoric ore bacterial and eucaryal microbial diversity ...

    African Journals Online (AJOL)

    These findings provided new opportunities into phosphoric ore microbiology that could be useful in biological system removing waste gases generated from the phosphoric industry. Keywords: Microbial community, bacteria, archaea, eucarya, mining residue. African Journal of Biotechnology, Vol 13(30) 3023-3029 ...

  3. Enhancement of transglutaminase activity by NMR identification of its flexible residues affecting the active site.

    Science.gov (United States)

    Shimba, Nobuhisa; Shinohara, Mina; Yokoyama, Kei ichi; Kashiwagi, Tatsuki; Ishikawa, Kohki; Ejima, Daisuke; Suzuki, Ei ichiro

    2002-04-24

    Incorporation of inter- or intramolecular covalent cross-links into food proteins with microbial transglutaminase (MTG) improves the physical and textural properties of many food proteins, such as tofu, boiled fish paste, and sausage. By using nuclear magnetic resonance, we have shown that the residues exhibiting relatively high flexibility in MTG are localized in the N-terminal region; however, the N-terminal region influences the microenvironment of the active site. These results suggest that the N-terminal region is not of primary importance for the global fold, but influences the substrate binding. Therefore, in order to increase the transglutaminase activity, the N-terminal residues were chosen as candidates for site-directed replacement and deletion. We obtained several mutants with higher activity, del1-2, del1-3, and S2R. We propose a strategy for enzyme engineering targeted toward flexible regions involved in the enzymatic activity. In addition, we also briefly describe how the number of glutamine residues in a substrate protein can be increased by mixing more than two kinds of TGases with different substrate specificities.

  4. Handling of Solid Residues

    International Nuclear Information System (INIS)

    Medina Bermudez, Clara Ines

    1999-01-01

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  5. Influx of CO2 from Soil Incubated Organic Residues at Constant Temperature

    Directory of Open Access Journals (Sweden)

    Shoukat Ali Abro

    2016-06-01

    Full Text Available Temperature induced CO2 from genotypic residue substances is still less understood. Two types of organic residues (wheat- maize were incubated at a constant temperature (25°C to determine the rate and cumulative influx of CO2 in laboratory experiment for 40 days. Further, the effect of surface and incorporated crop residues with and without phosphorus addition was also studied. Results revealed that mixing of crop residues increased CO2-C evolution significantly & emission rare was 37% higher than that of control. At constant temperature, soil mixed residues, had higher emission rates CO2-C than the residues superimposed. There was linear correlation of CO2-C influxed for phosphorus levels and residue application ways with entire incubation at constant temperature. The mixing of organic residues to soil enhanced SOC levels and biomass of microbially bound N; however to little degree ammonium (NH4-N and nitrate NO3-N nitrogen were decreased.

  6. Classical theory of algebraic numbers

    CERN Document Server

    Ribenboim, Paulo

    2001-01-01

    Gauss created the theory of binary quadratic forms in "Disquisitiones Arithmeticae" and Kummer invented ideals and the theory of cyclotomic fields in his attempt to prove Fermat's Last Theorem These were the starting points for the theory of algebraic numbers, developed in the classical papers of Dedekind, Dirichlet, Eisenstein, Hermite and many others This theory, enriched with more recent contributions, is of basic importance in the study of diophantine equations and arithmetic algebraic geometry, including methods in cryptography This book has a clear and thorough exposition of the classical theory of algebraic numbers, and contains a large number of exercises as well as worked out numerical examples The Introduction is a recapitulation of results about principal ideal domains, unique factorization domains and commutative fields Part One is devoted to residue classes and quadratic residues In Part Two one finds the study of algebraic integers, ideals, units, class numbers, the theory of decomposition, iner...

  7. Microbial safety of foods

    International Nuclear Information System (INIS)

    Bandekar, J.R.

    2013-01-01

    Despite advances in hygiene, consumer knowledge and food treatment and processing, food-borne diseases have become one of the most widespread public health problems in the world to-day. About two thirds of all outbreaks are traced to microbial contaminated food - one of the most hazardous being Clostridium botulinum, E. coli 0157: H7 and Salmonella. The pathogens can be introduced in the food products anywhere in the food chain and hence it is of prime important to have microbial vigilance in the entire food chain. WHO estimates that food-borne and water-borne diarrhoeal diseases taken together kill about 2.2 million people annually. The infants, children, elderly and immune-compromised people are particularly susceptible to food-borne diseases. Unsafe food causes many acute and life-long diseases, ranging from diarrhoeal diseases to various forms of cancer. A number of factors such as emergence of new food-borne pathogens, development of drug resistance in the pathogens, changing life style, global trade of food etc. are responsible for the continued persistence of food-borne diseases. Due to consumer demand, a number of Ready-To-Eat (RTE) minimally processed foods are increasingly marketed. However, there is increased risk of food-borne diseases with these products. The food-borne disease outbreaks due to E. coli O157:H7, Listeria monocytogenes, Salmonella and Campylobacter are responsible for recall of many foods resulting in heavy losses to food industry. The development of multi drug resistant pathogens due to indiscriminate use of antibiotics is also a major problem. Food Technology Division of Bhabha Atomic Research Centre has been working on food-borne bacterial pathogens particularly Salmonella, Campylobacter, Vibrio and Aeromonas species, their prevalence in export quality seafood as well in foods sold in retail market such as poultry, fish, sprouts and salads. These pathogens from Indian foods have been characterized for the presence of virulence genes

  8. MICROBIAL FUEL CELL

    DEFF Research Database (Denmark)

    2008-01-01

    A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

  9. Phototrophic Microbial Mats

    NARCIS (Netherlands)

    Stal, L.J.; Bolhuis, H.; Cretoiu, M.S.

    2017-01-01

    Microbial mats are structured, small-scale microbial ecosystems, andsimilar as biofilms cover a substratum like a tissue. A general characteristic of amicrobial mat is the steep physicochemical gradients that are the result of the metabolicactivities of the mat microorganisms. Virtually every

  10. [Residual neuromuscular blockade].

    Science.gov (United States)

    Fuchs-Buder, T; Schmartz, D

    2017-06-01

    Even small degrees of residual neuromuscular blockade, i. e. a train-of-four (TOF) ratio >0.6, may lead to clinically relevant consequences for the patient. Especially upper airway integrity and the ability to swallow may still be markedly impaired. Moreover, increasing evidence suggests that residual neuromuscular blockade may affect postoperative outcome of patients. The incidence of these small degrees of residual blockade is relatively high and may persist for more than 90 min after a single intubating dose of an intermediately acting neuromuscular blocking agent, such as rocuronium and atracurium. Both neuromuscular monitoring and pharmacological reversal are key elements for the prevention of postoperative residual blockade.

  11. TENORM: Wastewater Treatment Residuals

    Science.gov (United States)

    Water and wastes which have been discharged into municipal sewers are treated at wastewater treatment plants. These may contain trace amounts of both man-made and naturally occurring radionuclides which can accumulate in the treatment plant and residuals.

  12. Microbial communities inhabiting hypersaline microbial mats from the Abu Dhabi sabkha

    Science.gov (United States)

    Andrade, Luiza; Dutton, Kirsten; Paul, Andreas; van der Land, Cees; Sherry, Angela; Lokier, Stephen; Head, Ian

    2017-04-01

    Microbial mats are organo-sedimentary structures that are typically found in areas with extreme environmental conditions. Since these ecosystems are considered to be representative of the oldest forms of life on Earth, the study of microbial mats can inform our understanding of the development of life early in the history of our planet. In this study, we used hypersaline microbial mats from the Abu Dhabi sabkha (coastal salt flats). Cores of microbial mats (ca. 90 mm depth) were collected within an intertidal region. The cores were sliced into layers 2-3 mm thick and genomic DNA was extracted from each layer. A fragment of the 16S rRNA encoding gene was amplified in all DNA extracts, using barcoded primers, and the amplicons sequenced with the Ion Torrent platform to investigate the composition of the microbial communities down the depth of the cores. Preliminary results revealed a high proportion of Archaea (15.5-40.8% abundance) in all layers, with Halobacteria appearing to be more significant in the first 40 mm (0.4-10.3% of the total microbial community). Members of the Deltaproteobacteria were dominant in almost all layers of the microbial mat (≤ 48.6% relative abundance); however this dominance was not reflected in the first 8 mm, where the abundance was less than 2%. Chloroflexi and Anaerolinea, representing 93% of bacterial abundance, dominated the first 8 mm depth and decreased at greater depth (≤ 3% relative abundance). Cyanobacteria were found only in the top 10 mm, with unexpected low abundance (≤ 3% of the total number of reads). These results show a vertical zonation of microbial communities and processes in the microbial mats. Further analyses are underway to investigate if these patterns are repeated at other sites along a transect of the sabkha, and to relate the microbial composition to the physical-chemical conditions of the sites.

  13. Residuation in orthomodular lattices

    Directory of Open Access Journals (Sweden)

    Chajda Ivan

    2017-04-01

    Full Text Available We show that every idempotent weakly divisible residuated lattice satisfying the double negation law can be transformed into an orthomodular lattice. The converse holds if adjointness is replaced by conditional adjointness. Moreover, we show that every positive right residuated lattice satisfying the double negation law and two further simple identities can be converted into an orthomodular lattice. In this case, also the converse statement is true and the corresponence is nearly one-to-one.

  14. Residual Liquefaction under Standing Waves

    DEFF Research Database (Denmark)

    Kirca, V.S. Ozgur; Sumer, B. Mutlu; Fredsøe, Jørgen

    2012-01-01

    This paper summarizes the results of an experimental study which deals with the residual liquefaction of seabed under standing waves. It is shown that the seabed liquefaction under standing waves, although qualitatively similar, exhibits features different from that caused by progressive waves....... The experimental results show that the buildup of pore-water pressure and the resulting liquefaction first starts at the nodal section and spreads towards the antinodal section. The number of waves to cause liquefaction at the nodal section appears to be equal to that experienced in progressive waves for the same...

  15. Characterization of Hospital Residuals

    International Nuclear Information System (INIS)

    Blanco Meza, A.; Bonilla Jimenez, S.

    1997-01-01

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author) [es

  16. Theory of microbial genome evolution

    Science.gov (United States)

    Koonin, Eugene

    Bacteria and archaea have small genomes tightly packed with protein-coding genes. This compactness is commonly perceived as evidence of adaptive genome streamlining caused by strong purifying selection in large microbial populations. In such populations, even the small cost incurred by nonfunctional DNA because of extra energy and time expenditure is thought to be sufficient for this extra genetic material to be eliminated by selection. However, contrary to the predictions of this model, there exists a consistent, positive correlation between the strength of selection at the protein sequence level, measured as the ratio of nonsynonymous to synonymous substitution rates, and microbial genome size. By fitting the genome size distributions in multiple groups of prokaryotes to predictions of mathematical models of population evolution, we show that only models in which acquisition of additional genes is, on average, slightly beneficial yield a good fit to genomic data. Thus, the number of genes in prokaryotic genomes seems to reflect the equilibrium between the benefit of additional genes that diminishes as the genome grows and deletion bias. New genes acquired by microbial genomes, on average, appear to be adaptive. Evolution of bacterial and archaeal genomes involves extensive horizontal gene transfer and gene loss. Many microbes have open pangenomes, where each newly sequenced genome contains more than 10% `ORFans', genes without detectable homologues in other species. A simple, steady-state evolutionary model reveals two sharply distinct classes of microbial genes, one of which (ORFans) is characterized by effectively instantaneous gene replacement, whereas the other consists of genes with finite, distributed replacement rates. These findings imply a conservative estimate of at least a billion distinct genes in the prokaryotic genomic universe.

  17. Efficient particle filtering through residual nudging

    KAUST Repository

    Luo, Xiaodong

    2013-05-15

    We introduce an auxiliary technique, called residual nudging, to the particle filter to enhance its performance in cases where it performs poorly. The main idea of residual nudging is to monitor and, if necessary, adjust the residual norm of a state estimate in the observation space so that it does not exceed a pre-specified threshold. We suggest a rule to choose the pre-specified threshold, and construct a state estimate accordingly to achieve this objective. Numerical experiments suggest that introducing residual nudging to a particle filter may (substantially) improve its performance, in terms of filter accuracy and/or stability against divergence, especially when the particle filter is implemented with a relatively small number of particles. © 2013 Royal Meteorological Society.

  18. Management of NORM Residues

    International Nuclear Information System (INIS)

    2013-06-01

    The IAEA attaches great importance to the dissemination of information that can assist Member States in the development, implementation, maintenance and continuous improvement of systems, programmes and activities that support the nuclear fuel cycle and nuclear applications, and that address the legacy of past practices and accidents. However, radioactive residues are found not only in nuclear fuel cycle activities, but also in a range of other industrial activities, including: - Mining and milling of metalliferous and non-metallic ores; - Production of non-nuclear fuels, including coal, oil and gas; - Extraction and purification of water (e.g. in the generation of geothermal energy, as drinking and industrial process water; in paper and pulp manufacturing processes); - Production of industrial minerals, including phosphate, clay and building materials; - Use of radionuclides, such as thorium, for properties other than their radioactivity. Naturally occurring radioactive material (NORM) may lead to exposures at some stage of these processes and in the use or reuse of products, residues or wastes. Several IAEA publications address NORM issues with a special focus on some of the more relevant industrial operations. This publication attempts to provide guidance on managing residues arising from different NORM type industries, and on pertinent residue management strategies and technologies, to help Member States gain perspectives on the management of NORM residues

  19. Stable isotopes and biomarkers in microbial ecology

    NARCIS (Netherlands)

    Boschker, H.T.S.; Middelburg, J.J.

    2002-01-01

    The use of biomarkers in combination with stable isotope analysis is a new approach in microbial ecology and a number of papers on a variety of subjects have appeared. We will first discuss the techniques for analysing stable isotopes in biomarkers, primarily gas chromatography-combustion-isotope

  20. Hydrodynamics of microbial filter feeding

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

    2017-01-01

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate...

  1. Forum on Microbial Threats

    Science.gov (United States)

    2012-01-01

    communities adapt and respond to environmental stimuli; and potential applications for improving human, animal, plant, and ecosystem health... homeostasis ”, barrier integrity, and colonization re- sistance to pathogens. Research on these interactions will help to characterize microbial contributions

  2. Evolution of microbial pathogens

    National Research Council Canada - National Science Library

    DiRita, Victor J; Seifert, H. Steven

    2006-01-01

    ... A. Hogan vvi ■ CONTENTS 8. Evolution of Pathogens in Soil Rachel Muir and Man-Wah Tan / 131 9. Experimental Models of Symbiotic Host-Microbial Relationships: Understanding the Underpinnings of ...

  3. Lignin depolymerization by fungal secretomes and a microbial sink

    Energy Technology Data Exchange (ETDEWEB)

    Salvachúa, Davinia; Katahira, Rui; Cleveland, Nicholas S.; Khanna, Payal; Resch, Michael G.; Black, Brenna A.; Purvine, Samuel O.; Zink, Erika M.; Prieto, Alicia; Martínez, María J.; Martínez, Angel T.; Simmons, Blake A.; Gladden, John M.; Beckham, Gregg T.

    2016-08-25

    In Nature, powerful oxidative enzymes secreted by white rot fungi and some bacteria catalyze lignin depolymerization and some microbes are able to catabolize the resulting aromatic compounds as carbon and energy sources. Taken together, these two processes offer a potential route for microbial valorization of lignin. However, many challenges remain in realizing this concept, including that oxidative enzymes responsible for lignin depolymerization also catalyze polymerization of low molecular weight (LMW) lignin. Here, multiple basidiomycete secretomes were screened for ligninolytic enzyme activities in the presence of a residual lignin solid stream from a corn stover biorefinery, dubbed DMR-EH (Deacetylation, Mechanical Refining, and Enzymatic Hydrolysis) lignin. Two selected fungal secretomes, with high levels of laccases and peroxidases, were utilized for DMR-EH lignin depolymerization assays. The secretome from Pleurotus eryngii, which exhibited the highest laccase activity, reduced the lignin average molecular weight by 63% and 75% at pH 7 compared to the Mw of the control treated at the same conditions and the initial DMR-EH lignin, respectively, and was applied in further depolymerization assays as a function of time. As repolymerization was observed after 3 days of incubation, an aromatic-catabolic microbe (Pseudomonas putida KT2440) was incubated with the fungal secretome and DMR-EH lignin. These experiments demonstrated that the presence of the bacterium enhances lignin depolymerization, likely due to bacterial catabolism of LMW lignin, which may partially prevent repolymerization. In addition, proteomics was also applied to the P. eryngii secretome to identify the enzymes present in the fungal cocktail utilized for the depolymerization assays, which highlighted a significant number of glucose/ methanol/choline (GMC) oxidoreductases and laccases. Overall, this study demonstrates that ligninolytic enzymes can be used to partially depolymerize a solid, high

  4. Evidence of nitrification and denitrification in high and low microbial abundance sponges

    OpenAIRE

    Schläppy, Marie-Lise; Schöttner, Sandra I.; Lavik, Gaute; Kuypers, Marcel M. M.; de Beer, Dirk; Hoffmann, Friederike

    2009-01-01

    Aerobic and anaerobic microbial key processes were quantified and compared to microbial numbers and morphological structure in Mediterranean sponges. Direct counts on histological sections stained with DAPI showed that sponges with high microbial abundances (HMA sponges) have a denser morphological structure with a reduced aquiferous system compared to low microbial abundance (LMA) sponges. In Dysidea avara, the LMA sponge, rates of nitrification and denitrification were higher than in the HM...

  5. Residual-stress measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ezeilo, A.N.; Webster, G.A. [Imperial College, London (United Kingdom); Webster, P.J. [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  6. Ocean microbial metagenomics

    Science.gov (United States)

    Kerkhof, Lee J.; Goodman, Robert M.

    2009-09-01

    Technology for accessing the genomic DNA of microorganisms, directly from environmental samples without prior cultivation, has opened new vistas to understanding microbial diversity and functions. Especially as applied to soils and the oceans, environments on Earth where microbial diversity is vast, metagenomics and its emergent approaches have the power to transform rapidly our understanding of environmental microbiology. Here we explore select recent applications of the metagenomic suite to ocean microbiology.

  7. Effect of residual H2O2 from advanced oxidation processes on subsequent biological water treatmen : A laboratory batch study

    NARCIS (Netherlands)

    Wang, F.; van Halem, D.; Liu, G.; Lekkerkerker-Teunissen, K.; van der Hoek, J.P.

    2017-01-01

    H2O2 residuals from advanced oxidation processes (AOPs) may have critical impacts on the microbial ecology and performance of subsequent biological treatment processes, but little is known. The objective of this study was to evaluate how H2O2 residuals influence sand systems with an emphasis on

  8. Starch encapsulation of microbial pesticides for sustained activity

    International Nuclear Information System (INIS)

    McGuire, M.R.; Shasha, B.S.

    1994-01-01

    Many environmental and biological factors act to reduce the insecticidal potential of microbial pesticides. Each of these factors can be addressed through formulation. Over the past five years, we have investigated formulation of microbial insecticides within starch matrices. While chemical pesticides have been encapsulated in starch for many years, the biological nature of microbial insecticides has prohibited the use of the harsh chemicals or extreme pH necessary to ensure gelatinization of the starch and subsequent entrapment of active ingredient. Pregelatinized starches and flours have facilitated formulation of microbial pesticides. Three distinct types of starch formulations have been developed: a sprayable and two granular baits. Bioassays of cotton or cabbage leaf tissue treated with the sprayable formulations demonstrated increased residual activity of Bacillus thuringiensis kurstaki (Btk) after simulated (greenhouse) or actual (field) rainfall. Similarly, experiments with small field plots of cabbage treated with the sprayable formulations demonstrated efficacy similar to that of conventional chemical insecticides. The granular formulations have been tested extensively against European corn borer in whorl stage corn. Sunlight screens incorporated within the granules significantly increased residual activity of Btk when granules were exposed to direct sunlight. Under field conditions, feeding stimulants allowed a decrease in Btk concentration without significant loss of inset control. Work with these formulations is continuing with the addition of viruses and fungi to our research program. Clearly, improvements to formulations of microbial pesticides will enhance the acceptance and reliability of these important pest control tools. 22 refs, 5 figs, 8 tabs

  9. Microbial bioinformatics 2020.

    Science.gov (United States)

    Pallen, Mark J

    2016-09-01

    Microbial bioinformatics in 2020 will remain a vibrant, creative discipline, adding value to the ever-growing flood of new sequence data, while embracing novel technologies and fresh approaches. Databases and search strategies will struggle to cope and manual curation will not be sustainable during the scale-up to the million-microbial-genome era. Microbial taxonomy will have to adapt to a situation in which most microorganisms are discovered and characterised through the analysis of sequences. Genome sequencing will become a routine approach in clinical and research laboratories, with fresh demands for interpretable user-friendly outputs. The "internet of things" will penetrate healthcare systems, so that even a piece of hospital plumbing might have its own IP address that can be integrated with pathogen genome sequences. Microbiome mania will continue, but the tide will turn from molecular barcoding towards metagenomics. Crowd-sourced analyses will collide with cloud computing, but eternal vigilance will be the price of preventing the misinterpretation and overselling of microbial sequence data. Output from hand-held sequencers will be analysed on mobile devices. Open-source training materials will address the need for the development of a skilled labour force. As we boldly go into the third decade of the twenty-first century, microbial sequence space will remain the final frontier! © 2016 The Author. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  10. Anode microbial communities produced by changing from microbial fuel cell to microbial electrolysis cell operation using two different wastewaters

    KAUST Repository

    Kiely, Patrick D.

    2011-01-01

    Conditions in microbial fuel cells (MFCs) differ from those in microbial electrolysis cells (MECs) due to the intrusion of oxygen through the cathode and the release of H2 gas into solution. Based on 16S rRNA gene clone libraries, anode communities in reactors fed acetic acid decreased in species richness and diversity, and increased in numbers of Geobacter sulfurreducens, when reactors were shifted from MFCs to MECs. With a complex source of organic matter (potato wastewater), the proportion of Geobacteraceae remained constant when MFCs were converted into MECs, but the percentage of clones belonging to G. sulfurreducens decreased and the percentage of G. metallireducens clones increased. A dairy manure wastewater-fed MFC produced little power, and had more diverse microbial communities, but did not generate current in an MEC. These results show changes in Geobacter species in response to the MEC environment and that higher species diversity is not correlated with current. © 2010 Elsevier Ltd.

  11. QA/QC in pesticide residue analysis

    International Nuclear Information System (INIS)

    Ambrus, A.

    2002-01-01

    This paper outlines problems related to pesticide residue analysis in a regulatory laboratory that are related to: availability of reference materials, as over 1000 pesticide active ingredients are currently in use and over 400 crops represent a large part of a healthy diet; analysis time; availability of samples in sufficient numbers; uncertainties of the procedures

  12. Composition of carbonization residues

    Energy Technology Data Exchange (ETDEWEB)

    Hupfer; Leonhardt

    1943-11-27

    This report compared the composition of samples from Wesseling and Leuna. In each case the sample was a residue from carbonization of the residues from hydrogenation of the brown coal processed at the plant. The composition was given in terms of volatile components, fixed carbon, ash, water, carbon, hydrogen, oxygen, nitrogen, volatile sulfur, and total sulfur. The result of carbonization was given in terms of (ash and) coke, tar, water, gas and losses, and bitumen. The composition of the ash was given in terms of silicon dioxide, ferric oxide, aluminum oxide, calcium oxide, magnesium oxide, potassium and sodium oxides, sulfur trioxide, phosphorus pentoxide, chlorine, and titanium oxide. The most important difference between the properties of the two samples was that the residue from Wesseling only contained 4% oil, whereas that from Leuna had about 26% oil. Taking into account the total amount of residue processed yearly, the report noted that better carbonization at Leuna could save 20,000 metric tons/year of oil. Some other comparisons of data included about 33% volatiles at Leuna vs. about 22% at Wesseling, about 5 1/2% sulfur at Leuna vs. about 6 1/2% at Leuna, but about 57% ash for both. Composition of the ash differed quite a bit between the two. 1 table.

  13. Designing with residual materials

    NARCIS (Netherlands)

    Walhout, W.; Wever, R.; Blom, E.; Addink-Dölle, L.; Tempelman, E.

    2013-01-01

    Many entrepreneurial businesses have attempted to create value based on the residual material streams of third parties. Based on ‘waste’ materials they designed products, around which they built their company. Such activities have the potential to yield sustainable products. Many of such companies

  14. Radiation application for the utilization of microbial resources

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Keun; Kim, Jae Sung; Lee, Sang Jae (and others)

    2007-07-15

    Domestic microbes which had the antifungal, pesticide residue degradable, and heavy metal adsorbent activities were isolated individually. Mutants of their improved functions were induced by radiation. And finally microbial formulae of biocontroller were manufactured and respected to be industrialized promisingly. The effectiveness of the developed microbial formulae were confirmed in pepper, radish, and Chinese cabbage by field experiments for 5 kinds of fungal diseases. This technology is respected to be transferred to the agricultural companies. And a novel venture company could be established by the involved researchers using this technology. As a result, the productivity in environmentally-friendly farm could be improved gradually in the near future.

  15. Radiation application for the utilization of microbial resources

    International Nuclear Information System (INIS)

    Lee, Young Keun; Kim, Jae Sung; Lee, Sang Jae

    2007-07-01

    Domestic microbes which had the antifungal, pesticide residue degradable, and heavy metal adsorbent activities were isolated individually. Mutants of their improved functions were induced by radiation. And finally microbial formulae of biocontroller were manufactured and respected to be industrialized promisingly. The effectiveness of the developed microbial formulae were confirmed in pepper, radish, and Chinese cabbage by field experiments for 5 kinds of fungal diseases. This technology is respected to be transferred to the agricultural companies. And a novel venture company could be established by the involved researchers using this technology. As a result, the productivity in environmentally-friendly farm could be improved gradually in the near future

  16. Microbial flora analysis for the degradation of beta-cypermethrin.

    Science.gov (United States)

    Qi, Zhang; Wei, Zhang

    2017-03-01

    In the Xinjiang region of Eurasia, sustained long-term and continuous cropping of cotton over a wide expanse of land is practiced, which requires application of high levels of pyrethroid and other classes of pesticides-resulting in high levels of pesticide residues in the soil. In this study, soil samples were collected from areas of long-term continuous cotton crops with the aim of obtaining microbial resources applicable for remediation of pyrethroid pesticide contamination suitable for the soil type and climate of that area. Soil samples were first used to culture microbial flora capable of degrading beta-cypermethrin using an enrichment culture method. Structural changes and ultimate microbial floral composition during enrichment were analyzed by high-throughput sequencing. Four strains capable of degrading beta-cypermethrin were isolated and preliminarily classified. Finally, comparative rates and speeds of degradation of beta-cypermethrin between relevant microbial flora and single strains were determined. After continuous subculture for 3 weeks, soil sample microbial flora formed a new type of microbial flora by rapid succession, which showed stable growth by utilizing beta-cypermethrin as the sole carbon source (GXzq). This microbial flora mainly consisted of Pseudomonas, Hyphomicrobium, Dokdonella, and Methyloversatilis. Analysis of the microbial flora also permitted separation of four additional strains; i.e., GXZQ4, GXZQ6, GXZQ7, and GXZQ13 that, respectively, belonged to Streptomyces, Enterobacter, Streptomyces, and Pseudomonas. Under culture conditions of 37 °C and 180 rpm, the degradation rate of beta-cypermethrin by GXzq was as high as 89.84% within 96 h, which exceeded that achieved by the single strains GXZQ4, GXZQ6, GXZQ7, and GXZQ13 and their derived microbial flora GXh.

  17. ASSESSMENT OF THE BIODIVERSITY OF SAMPLES USED FOR ISOLATION OF MICROBIAL STRAINS CAPABLE OF CONVERTING STRAW DESTINED AS A SUBSTRATE FOR BIOGAS PLANT

    Directory of Open Access Journals (Sweden)

    Krystyna Cybulska

    2016-01-01

    Full Text Available In biogas plants, almost any type of organic matter can be used as a substrate to produce biogas. To make the process of methane fermentation more effective, these materials are pretreated. This applies in particular to a group of difficult substrates. Straw, due to its hemicellulose structure and saturation, is hardly fermented by biogas reactor microorganisms. The methods of post-harvest residue preparation for anaerobic digestion being applied so far are expensive, while their application has a negative effect on methanoegenic bacteria. Therefore, the microorganisms being able to degrade straw hemicellulose structure, utilisation of which could precede the proper fermentation process, have been searched for. This paper presents the results of microbial biodiversity analysis in the environmental samples being lupin, cereal, rape and maize straw as well as hay and haylage at different degradation stages. The analysis of biodiversity will help at a further stage of study to isolate active microbial strains showing cellulolytic, hemicellulolytic or ligninolytic activity which are desirable in the process of straw biodegradation. Analysis of the microbial count was performed by the method of deep inoculation on different microbiological culture media. The conducted tests include determination of the number of fungi, bacteria and actinomycetes. The results obtained confirm the usefulness of the analysed samples for isolation of microbial strains capable of converting straw preceding the biogas production.

  18. Effects of coffee processing residues on anaerobic microorganisms and corresponding digestion performance.

    Science.gov (United States)

    Rojas-Sossa, Juan Pablo; Murillo-Roos, Mariana; Uribe, Lidieth; Uribe-Lorio, Lorena; Marsh, Terence; Larsen, Niels; Chen, Rui; Miranda, Alberto; Solís, Kattia; Rodriguez, Werner; Kirk, Dana; Liao, Wei

    2017-12-01

    The objective of this study was to delineate the effects of different coffee processing residues on the anaerobic microbes and corresponding digestion performance. The results elucidated that mucilage-rich feed enhanced the accumulation of methanogens, which consequently led to better digestion performance of biogas production. Fifty percent more methane and up to 3 times more net energy (heat and electricity) output were achieved by the digestion of the mucilage-rich feed (M3). The microbial community and statistical analyses further elucidated that different residues in the feed had significant impact on microbial distribution and correspondingly influenced the digestion performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Deep subsurface microbial processes

    Science.gov (United States)

    Lovley, D.R.; Chapelle, F.H.

    1995-01-01

    Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed redox reactions that influence the geophysical properties of these environments. Furthermore, there is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by man's activities, and there is a need to predict the extent to which microbial activity may remediate such contamination. Metabolically active microorganisms can be recovered from a diversity of deep subsurface environments. The available evidence suggests that these microorganisms are responsible for catalyzing the oxidation of organic matter coupled to a variety of electron acceptors just as microorganisms do in surface sediments, but at much slower rates. The technical difficulties in aseptically sampling deep subsurface sediments and the fact that microbial processes in laboratory incubations of deep subsurface material often do not mimic in situ processes frequently necessitate that microbial activity in the deep subsurface be inferred through nonmicrobiological analyses of ground water. These approaches include measurements of dissolved H2, which can predict the predominant microbially catalyzed redox reactions in aquifers, as well as geochemical and groundwater flow modeling, which can be used to estimate the rates of microbial processes. Microorganisms recovered from the deep subsurface have the potential to affect the fate of toxic organics and inorganic contaminants in groundwater. Microbial activity also greatly influences 1 the chemistry of many pristine groundwaters and contributes to such phenomena as porosity development in carbonate aquifers, accumulation of undesirably high concentrations of dissolved iron, and production of methane and hydrogen sulfide. Although the last decade has seen a dramatic increase in interest in deep subsurface microbiology, in comparison with the study of

  20. Anthropogenic perturbations in marine microbial communities.

    Science.gov (United States)

    Nogales, Balbina; Lanfranconi, Mariana P; Piña-Villalonga, Juana M; Bosch, Rafael

    2011-03-01

    Human activities impact marine ecosystems at a global scale and all levels of complexity of life. Despite their importance as key players in ecosystem processes, the stress caused to microorganisms has been greatly neglected. This fact is aggravated by difficulties in the analysis of microbial communities and their high diversity, making the definition of patterns difficult. In this review, we discuss the effects of nutrient increase, pollution by organic chemicals and heavy metals and the introduction of antibiotics and pathogens into the environment. Microbial communities respond positively to nutrients and chemical pollution by increasing cell numbers. There are also significant changes in community composition, increases in diversity and high temporal variability. These changes, which evidence the modification of the environmental conditions due to anthropogenic stress, usually alter community functionality, although this aspect has not been explored in depth. Altered microbial communities in human-impacted marine environments can in turn have detrimental effects on human health (i.e. spread of pathogens and antibiotic resistance). New threats to marine ecosystems, i.e. related to climate change, could also have an impact on microbial communities. Therefore, an effort dedicated to analyse the microbial compartment in detail should be made when studying the impact of anthropogenic activities on marine ecosystems. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  1. Screening of antibiotics and chemical analysis of penicillin residue in fresh milk and traditional dairy products in Oyo state, Nigeria

    OpenAIRE

    Olatoye, Isaac Olufemi; Daniel, Oluwayemisi Folashade; Ishola, Sunday Ayobami

    2016-01-01

    Background and Aim: There are global public health and economic concerns on chemical residues in food of animal origin. The use of antibiotics in dairy cattle for the treatment of diseases such as mastitis has contributed to the presence of residues in dairy products. Penicillin residues as low as 1 ppb can lead to allergic reactions and shift of resistance patterns in microbial population as well as interfere with the processing of several dairy products. Antibiotic monitoring is an essentia...

  2. Detection of antibiotic residues in food by Charm II test

    International Nuclear Information System (INIS)

    Addali, Mohamed

    2014-01-01

    Antibiotics are used in food to: -therapy and prophylaxis, -increase the productivity of the food producing animals. The presence of antimicrobial residues: -constitutes a potential human health hazard. has significant impact on international food trade. has implications on technological process in dairy industry. Detection of antibiotic residues is of great interest. It helps protect humans against the effects of such residues, the more it can support the participation of our country in international trade. Charm II test is one of the methods of detection of antimicrobial residues. The tests utilize microbial or antibody receptor assay technology. The sample is incubated with a binding agent (microbial cells with specific receptor sites or with specific antibodies attached) and a tracer (the radio-labeled version of the antibiotic to be detected). The amount of tracer on the binding agent is measured using a scintillation counter and is compared to a pre-determined cut-off or control point. If contaminating antibiotic is present, it will prevent the binding of the tracer by occupying the receptors on the binding agent. The less labeled tracer detected, the more contaminating antibiotic there is present in the sample. This work, carried out at the Radiochemical Laboratory of the National Centre of Nuclear Science and Technology, has two parts: 1/ The first is reserved to a literature review provides an overview on antibiotics and the charm II method. 2/ The second is devoted to the experimental study and presentation of results.

  3. Computational Profiling of Microbial Genomes using Short Sequences

    Science.gov (United States)

    Doering, Dale; Tsukuda, Toyoko

    2001-03-01

    The genomes of a number of microbial species have now been completely sequenced. We have developed a program for the statistical analysis of the appearance frequency and location of short DNA segments within an entire microbial genome. Using this program, the genomes of Methanococcus jannischii (1.66 Mbase; 68radiodurans (3.28 Mbase; 66and compared to a randomly generated genomic pattern. The random sequence shows the expected statistical frequency distribution about the average that equals the genome size divided by the total number of N size short segments (4N). In contrast, the microbial genomes are radically skewed with a large number of segments that rarely occur and a few that are highly represented in the genome. The specific distribution profile of the segments is strongly dependent on the overall bias in the organism. The biased appearance frequency allows us to develop a genome signature of each microbial species.

  4. Microbial contamination detection at low levels by [125]I radiolabeling

    Science.gov (United States)

    Summers, David; Karouia, Fathi

    Contamination of mission spacecraft is an ongoing issue. A broad diversity of microorganisms have been detected in clean rooms where spacecraft are assembled. Some of which, depicted as oligotroph, are of special regard, as they are capable of colonizing inorganic surfaces like metal, and have been shown to be a concern for forward contamination of pristine celestial bodies. Currently, the NASA standard assay is the only approved assay intended for the enumeration of spores and heterotrophic microbial populations. However, culture-based microbial detection methods underestimate the viable microbial population. More recently, adenosine triphosphate (ATP) bioluminescence and limulus amebocyte lysate (LAL) assays, which employ measure-ments of selected metabolic products as a proxy of biomass, have been used successfully to circumvent the necessity of the growth of microorganisms in order to estimate the biodurdens associated with spacecraft assembly facility. However, these methods have limitation in the amount of cells that can be detected, i.e., 103 cells, and the type of microorganisms respec-tively. This work seeks to develop a new highly sensitive method for the determination of bioburdens (and the detection of microorganisms and life) that is independant of the type of organism while preserving a good turn-around time for analysis for planetary protection purposes. The assay is based on the detection of the organism's protein by labeling them by radioiodination, 125 I, of aromatic rings on tyrosine amino acids residues. Radiolabeling techniques are inherently sensitive and 125 I, in particular, benefits from a 60 day half-life, providing greater activity and signal per unit number of labels. Furthermore, microorganisms can contain over 50% of protein by dry weight. Thus, just one label per protein increases the sensitivity, compared to the ATP and LAL assays, by one and three orders of magnitude by using standard detection methods and the use of multiphoton

  5. Residual stresses in material processing

    Science.gov (United States)

    Kozaczek, K. J.; Watkins, T. R.; Hubbard, C. R.; Wang, Xun-Li; Spooner, S.

    Material manufacturing processes often introduce residual stresses into the product. The residual stresses affect the properties of the material and often are detrimental. Therefore, the distribution and magnitude of residual stresses in the final product are usually an important factor in manufacturing process optimization or component life prediction. The present paper briefly discusses the causes of residual stresses. It then addresses the direct, nondestructive methods of residual stress measurement by X ray and neutron diffraction. Examples are presented to demonstrate the importance of residual stress measurement in machining and joining operations.

  6. Enhancing biogas production from recalcitrant lignocellulosic residue

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis

    Lignocellulosic substrates are abundant in agricultural areas around the world and lately, are utilized for biogas production in full-scale anaerobic digesters. However, the anaerobic digestion (AD) of these substrates is associated with specific difficulties due to their recalcitrant nature which...... solution for augmented biomass solubilization without causing inhibition to the mandatory anaerobic methanogenic community. Based on the initial microbial analysis, the bioaugmentation with the typically abundant in AD systems C. thermocellum was examined in biogas reactors fed with wheat straw...... be periodically applied in biogas reactors in order to extract the residual methane from the amassing materials and avoid potential accumulation. Additionally, the facultative anaerobic Melioribacter roseus was inoculated in a replicate CSTR following different bioaugmentation strategies, either strictly...

  7. Recycling crop residues for use in recirculating hydroponic crop production

    Science.gov (United States)

    Mackowiak, C. L.; Garland, J. L.; Sager, J. C.

    1996-01-01

    As part of bioregenerative life support feasibility testing by NASA, crop residues are being used to resupply elemental nutrients to recirculating hydroponic crop production systems. Methods for recovering nutrients from crop residues have evolved from water soaking (leaching) to rapid aerobic bioreactor processing. Leaching residues recovered the majority of elements but it also recovered significant amounts of soluble organics. The high organic content of leachates was detrimental to plant growth. Aerobic bioreactor processing reduced the organic content ten-fold, which reduced or eliminated phytotoxic effects. Wheat and potato production studies were successful using effluents from reactors having with 8- to 1-day retention times. Aerobic bioreactor effluents supplied at least half of the crops elemental mass needs in these studies. Descriptions of leachate and effluent mineral content, biomass productivity, microbial activity, and nutrient budgets for potato and wheat are presented.

  8. DETERMINAÇÃO DE RESÍDUOS DE ANTIBIÓTICOS, UTILIZANDO-SE MÉTODOS DE INIBIÇÃO MICROBIANA, ENZIMÁTICO E IMUNO-ENSAIOS NO LEITE PASTEURIZADO COMERCIALIZADO NA REGIÃO NORTE DO ESTADO DO RIO DE JANEIRO, BRASIL ANTIBIOTICS RESIDUES DETERMINATION, USING MICROBIAL INHIBITION, PROTEIN-BINDING AND IMMUNOASSAYS METHODS, IN PASTEURIZED MILK COMMERCIALIZED IN THE NORTHERN REGION OF RIO DE JANEIRO STATE, BRAZIL

    Directory of Open Access Journals (Sweden)

    Marcio Manhães Folly

    2001-02-01

    presence of pathogenic microorganisms in milk. The objective of this research was to determine the frequency of contamination with antimicrobial residues in pasteurized type "C" and "Integral" milk commercialized in the northern region of Rio de Janeiro State, Brazil.. 300 samples of pasteurized type "C" milk (130 samples and "Integral" milk (170 samples from the northern region of Rio de Janeiro State were analysed using two rapid tests between April 1996 and April 1997. A contamination frequency of 4.33% with antimicrobial residues in milk was found utilizing parallel methods of microbial inhibition (Delvotest P and protein-binding (bL Snap Test. The separate utilization of the Delvotest P revealed a frequency of 3,66% and bL Snap Test of 1,66%. It was concluded that the milk in the northern region of Rio de Janeiro State was contaminated.

  9. SRC Residual fuel oils

    Science.gov (United States)

    Tewari, Krishna C.; Foster, Edward P.

    1985-01-01

    Coal solids (SRC) and distillate oils are combined to afford single-phase blends of residual oils which have utility as fuel oils substitutes. The components are combined on the basis of their respective polarities, that is, on the basis of their heteroatom content, to assure complete solubilization of SRC. The resulting composition is a fuel oil blend which retains its stability and homogeneity over the long term.

  10. Global Microbial Identifier

    DEFF Research Database (Denmark)

    Wielinga, Peter; Hendriksen, Rene S.; Aarestrup, Frank Møller

    2017-01-01

    -source systems. There is therefore an obvious need to develop a global system of whole microbial genome databases to aggregate, share, mine and use microbiological genomic data, to address global public health and clinical challenges, and most importantly to identify and diagnose infectious diseases. The global...... of microorganisms, for the identification of relevant genes and for the comparison of genomes to detect outbreaks and emerging pathogens. To harness the full potential of WGS, a shared global database of genomes linked to relevant metadata and the necessary software tools needs to be generated, hence the global...... microbial identifier (GMI) initiative. This tool will ideally be used in amongst others in the diagnosis of infectious diseases in humans and animals, in the identification of microorganisms in food and environment, and to track and trace microbial agents in all arenas globally. This will require...

  11. Advancing analytical algorithms and pipelines for billions of microbial sequences.

    Science.gov (United States)

    Gonzalez, Antonio; Knight, Rob

    2012-02-01

    The vast number of microbial sequences resulting from sequencing efforts using new technologies require us to re-assess currently available analysis methodologies and tools. Here we describe trends in the development and distribution of software for analyzing microbial sequence data. We then focus on one widely used set of methods, dimensionality reduction techniques, which allow users to summarize and compare these vast datasets. We conclude by emphasizing the utility of formal software engineering methods for the development of computational biology tools, and the need for new algorithms for comparing microbial communities. Such large-scale comparisons will allow us to fulfill the dream of rapid integration and comparison of microbial sequence data sets, in a replicable analytical environment, in order to describe the microbial world we inhabit. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Comparison of microbial communities from different Jinhua ham factories.

    Science.gov (United States)

    Ge, Qingfeng; Gu, Yubin; Zhang, Wangang; Yin, Yongqi; Yu, Hai; Wu, Mangang; Wang, Zhijun; Zhou, Guanghong

    2017-12-01

    Microbes in different aged workshops play important roles in the flavor formation of Jinhua ham. However, microbial diversity, community structure and age related changes in workshops are poorly understood. The microbial community structure and diversity in Jinhua ham produced in factories that have 5, 15, and 30 years of history in processing hams were compared using the pyrosequencing technique. Results showed that 571,703 high-quality sequences were obtained and located in 242 genera belonging to 18 phyla. Bacterial diversity and microbial community structure were significantly different with the years of workshops. Three-phase model to characterize the changes of ham microbial communities was proposed. Gas chromatography-mass spectrometry assays indicated that the hams produced in different aged workshops have great differences in number and relative contents of volatiles compounds. These results suggest that different aged factories could form special and well-balanced microbial diversity, which may contribute to the unique flavor characteristics in Jinhua ham.

  13. Composition of carbonization residues

    Energy Technology Data Exchange (ETDEWEB)

    Hupfer; Leonhardt

    1943-11-30

    This report gave a record of the composition of several samples of residues from carbonization of various hydrogenation residue from processing some type of coal or tar in the Bergius process. These included Silesian bituminous coal processed at 600 atm. with iron catalyst, in one case to produce gasoline and middle oil and in another case to produce heavy oil excess, Scholven coal processed at 250 atm. with tin oxalate and chlorine catalyst, Bruex tar processed in a 10-liter oven using iron catalyst, and a pitch mixture from Welheim processed in a 10-liter over using iron catalyst. The values gathered were compared with a few corresponding values estimated for Boehlen tar and Gelsenberg coal based on several assumptions outlined in the report. The data recorded included percentage of ash in the dry residue and percentage of carbon, hydrogen, oxygen, nitrogen, chlorine, total sulfur, and volatile sulfur. The percentage of ash varied from 21.43% in the case of Bruex tar to 53.15% in the case of one of the Silesian coals. Percentage of carbon varied from 44.0% in the case of Scholven coal to 78.03% in the case of Bruex tar. Percentage of total sulfur varied from 2.28% for Bruex tar to a recorded 5.65% for one of the Silesian coals and an estimated 6% for Boehlen tar. 1 table.

  14. Noise Residual Learning for Noise Modeling in Distributed Video Coding

    DEFF Research Database (Denmark)

    Luong, Huynh Van; Forchhammer, Søren

    2012-01-01

    Distributed video coding (DVC) is a coding paradigm which exploits the source statistics at the decoder side to reduce the complexity at the encoder. The noise model is one of the inherently difficult challenges in DVC. This paper considers Transform Domain Wyner-Ziv (TDWZ) coding and proposes...... noise residual learning techniques that take residues from previously decoded frames into account to estimate the decoding residue more precisely. Moreover, the techniques calculate a number of candidate noise residual distributions within a frame to adaptively optimize the soft side information during...

  15. Microbial Load Monitor

    Science.gov (United States)

    Gibson, S. F.; Royer, E. R.

    1979-01-01

    The Microbial Load Monitor (MLM) is an automated and computerized system for detection and identification of microorganisms. Additionally, the system is designed to enumerate and provide antimicrobic susceptibility profiles for medically significant bacteria. The system is designed to accomplish these tasks in a time of 13 hours or less versus the traditional time of 24 hours for negatives and 72 hours or more for positives usually required for standard microbiological analysis. The MLM concept differs from other methods of microbial detection in that the system is designed to accept raw untreated clinical samples and to selectively identify each group or species that may be present in a polymicrobic sample.

  16. EVA Suit Microbial Leakage Investigation

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to collect microbial samples from various EVA suits to determine how much microbial contamination is typically released during...

  17. Nitrogen Immobilization in Plant Growth Substrates: Clean Chip Residual, Pine Bark, and Peatmoss

    Directory of Open Access Journals (Sweden)

    Cheryl R. Boyer

    2012-01-01

    Full Text Available Rising costs of potting substrates have caused horticultural growers to search for alternative, lower-cost materials. Objectives of this study were to determine the extent of nitrogen immobilization and microbial respiration in a high wood-fiber content substrate, clean chip residual. Microbial activity and nitrogen availability of two screen sizes (0.95 cm and 0.48 cm of clean chip residual were compared to control treatments of pine bark and peatmoss in a 60-day incubation experiment. Four rates (0, 1, 2, or 3 mg of supplemental nitrogen were assessed. Peatmoss displayed little microbial respiration over the course of the study, regardless of nitrogen rate; followed by pine bark, 0.95 cm clean chip residual, and 0.48 cm clean chip residual. Respiration increased with increasing nitrogen. Total inorganic nitrogen (plant available nitrogen was greatest with peatmoss; inorganic nitrogen in other treatments were similar at the 0, 1, and 2 mg supplemental nitrogen rates, while an increase occurred with the highest rate (3 mg. Clean chip residual and pine bark were similar in available nitrogen compared to peatmoss. This study suggests that nitrogen immobilization in substrates composed of clean chip residual is similar to pine bark and can be treated with similar fertilizer amendments during nursery production.

  18. Methods of measuring residual stresses in components

    International Nuclear Information System (INIS)

    Rossini, N.S.; Dassisti, M.; Benyounis, K.Y.; Olabi, A.G.

    2012-01-01

    Highlights: ► Defining the different methods of measuring residual stresses in manufactured components. ► Comprehensive study on the hole drilling, neutron diffraction and other techniques. ► Evaluating advantage and disadvantage of each method. ► Advising the reader with the appropriate method to use. -- Abstract: Residual stresses occur in many manufactured structures and components. Large number of investigations have been carried out to study this phenomenon and its effect on the mechanical characteristics of these components. Over the years, different methods have been developed to measure residual stress for different types of components in order to obtain reliable assessment. The various specific methods have evolved over several decades and their practical applications have greatly benefited from the development of complementary technologies, notably in material cutting, full-field deformation measurement techniques, numerical methods and computing power. These complementary technologies have stimulated advances not only in measurement accuracy and reliability, but also in range of application; much greater detail in residual stresses measurement is now available. This paper aims to classify the different residual stresses measurement methods and to provide an overview of some of the recent advances in this area to help researchers on selecting their techniques among destructive, semi destructive and non-destructive techniques depends on their application and the availabilities of those techniques. For each method scope, physical limitation, advantages and disadvantages are summarized. In the end this paper indicates some promising directions for future developments.

  19. Special Issue on “Microbial Ecology of Anaerobic Digestion”

    Directory of Open Access Journals (Sweden)

    Sabine Kleinsteuber

    2014-06-01

    Full Text Available Anaerobic digestion (AD is an efficient and sustainable way of using organic carbon from residual biomass and organic waste for the production of renewable energy, while simultaneously recycling nutrients and cleaning up waste streams. The process relies on complex microbial communities comprised of diverse functional guilds; these communities have manifold metabolic pathways and interactions. In contrast to the conventional view of an anaerobic digester as a black box, advanced microbiological methods have paved the way for understanding and even controlling complex microbial networks. Nowadays, microbial resource management is crucial for technological progress in AD, and offers new perspectives concerning sustainable waste management, renewable energy production, resource efficiency, and advanced bio-refineries; these perspectives lead to novel applications of AD processes that go beyond biogas as the main product. [...

  20. Toward a microbial Neolithic revolution in buildings.

    Science.gov (United States)

    Thaler, David S

    2016-03-29

    The Neolithic revolution--the transition of our species from hunter and gatherer to cultivator--began approximately 14,000 years ago and is essentially complete for macroscopic food. Humans remain largely pre-Neolithic in our relationship with microbes but starting with the gut we continue our hundred-year project of approaching the ability to assess and cultivate benign microbiomes in our bodies. Buildings are analogous to the body and it is time to ask what it means to cultivate benign microbiomes in our built environment. A critical distinction is that we have not found, or invented, niches in buildings where healthful microbial metabolism occurs and/or could be cultivated. Key events affecting the health and healthfulness of buildings such as a hurricane leading to a flood or a burst pipe occur only rarely and unpredictably. The cause may be transient but the effects can be long lasting and, e.g., for moisture damage, cumulative. Non-invasive "building tomography" could find moisture and "sentinel microbes" could record the integral of transient growth. "Seed" microbes are metabolically inert cells able to grow when conditions allow. All microbes and their residue present actinic molecules including immunological epitopes (molecular shapes). The fascinating hygiene and microbial biodiversity hypotheses propose that a healthy immune system requires exposure to a set of microbial epitopes that is rich in diversity. A particular conjecture is that measures of the richness of diversity derived from microbiome next-generation sequencing (NGS) can be mechanistically coupled to--rather than merely correlated with some measures of--human health. These hypotheses and conjectures inspire workers and funders but an alternative is also consequent to the first Neolithic revolution: That the genetic uniformity of contemporary foods may also decrease human exposure to molecular biodiversity in a heath-relevant manner. Understanding the consequences--including the unintended

  1. Earthworms (Amynthas spp. increase common bean growth, microbial biomass, and soil respiration

    Directory of Open Access Journals (Sweden)

    Julierme Zimmer Barbosa

    2017-10-01

    Full Text Available Few studies have evaluated the effect of earthworms on plants and biological soil attributes, especially among legumes. The objective of this study was to evaluate the influence of earthworms (Amynthas spp. on growth in the common bean (Phaseolus vulgaris L. and on soil biological attributes. The experiment was conducted in a greenhouse using a completely randomized design with five treatments and eight repetitions. The treatments consisted of inoculation with five different quantities of earthworms of the genus Amynthas (0, 2, 4, 6, and 8 worms per pot. Each experimental unit consisted of a plastic pot containing 4 kg of soil and two common bean plants. The experiment was harvested 38 days after seedling emergence. Dry matter and plant height, soil respiration, microbial respiration, microbial biomass, and metabolic quotient were determined. Earthworm recovery in our study was high in number and mass, with all values above 91.6% and 89.1%, respectively. In addition, earthworm fresh biomass decreased only in the treatment that included eight earthworms per pot. The presence of earthworms increased the plant growth and improved soil biological properties, suggesting that agricultural practices that favor the presence of these organisms can be used to increase the production of common bean, and the increased soil CO2 emission caused by the earthworms can be partially offset by the addition of common bean crop residues to the soil.

  2. Stromatolites, Metals, Statistics and Microbial Mats: A Complex Interplay

    Science.gov (United States)

    Spear, J. R.

    2014-12-01

    Initially thought to be relatively 'simple' ecosystems for study, microbial mats have long been considered ideal for any number of research questions. Microbial mats can be found in any number of environments, both natural and manmade, and are typically dependent upon the physiochemical environment for their structure, maintenance and longevity. Ultimately, these and other parameters govern community whereby a microbial mat provides overall ecosystem services to their environment. On the edge of a hotspring in Yellowstone National Park we have found an active microbial mat community that can form a laminated, lithified, accretionary structure that is likely the best example of a living and growing stromatolite. In the outfall channel of the sulfidic Stinking Spring, Utah, we have found examples of both naturally occurring laminated and floating mats where the carbon flux is controlled by abiotic degassing of CO2 rather than metabolism. δ13C-bicarbonate uptake experiments reveal an autotrophic growth rate of 0 - 0.16%/day while δ13C-acetate reveals a higher heterotrophic growth rate of 0.03 - 0.65%/day, which highlights the role of heterotrophs in these mats. Similar growth experiments on Little Hot Creek, California laminated microbial mats reveal a trend for top-down microbial growth with similar microbial taxonomy and diversity to other mat-types. Of a curious note is that incubation experiments with Little Hot Creek mats reveals the importance of particular metals in mat structure and function. Statistically, alpha- and beta-diversity metrics are often used to characterize microbial communities in such systems, but from an analysis of a wastewater treatment system, Hill diversities can better interpret the effective number of species to produce an ecologically intuitive quantity to better understand a microbial mat ecosystem.

  3. Pretreatment of microbial sludges

    Science.gov (United States)

    Rivard, Christopher J.; Nagle, Nicholas J.

    1995-01-01

    Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

  4. Formation and Stability of Microbially Derived Soil Organic Matter

    Science.gov (United States)

    Waldrop, M. P.; Creamer, C.; Foster, A. L.; Lawrence, C. R.; Mcfarland, J. W.; Schulz, M. S.

    2017-12-01

    Soil carbon is vital to soil health, food security, and climate change mitigation, but the underlying mechanisms controlling the stabilization and destabilization of soil carbon are still poorly understood. There has been a conceptual paradigm shift in how soil organic matter is formed which now emphasizes the importance of microbial activity to build stable (i.e. long-lived) and mineral-associated soil organic matter. In this conceptual model, the consumption of plant carbon by microorganisms, followed by subsequent turnover of microbial bodies closely associated with mineral particles, produces a layering of amino acid and lipid residues on the surfaces of soil minerals that remains protected from destabilization by mineral-association and aggregation processes. We tested this new model by examining how isotopically labeled plant and microbial C differ in their fundamental stabilization and destabilization processes on soil minerals through a soil profile. We used a combination of laboratory and field-based approaches to bridge multiple spatial scales, and used soil depth as well as synthetic minerals to create gradients of soil mineralogy. We used Raman microscopy as a tool to probe organic matter association with mineral surfaces, as it allows for the simultaneous quantification and identification of living microbes, carbon, minerals, and isotopes through time. As expected, we found that the type of minerals present had a strong influence on the amount of C retained, but the stabilization of new C critically depends on growth, death, and turnover of microbial cells. Additionally, the destabilization of microbial residue C on mineral surfaces was little affected by flushes of DOC relative to wet-dry cycles alone. We believe this new insight into microbial mechanisms of C stabilization in soils will eventually lead to new avenues for measuring and modeling SOM dynamics in soils, and aid in the management of soil C to mediate global challenges.

  5. Integrating microbial physiology and physio-chemical principles in soils with the MIcrobial-MIneral Carbon Stabilization (MIMICS) model

    Science.gov (United States)

    Wieder, W. R.; Grandy, A. S.; Kallenbach, C. M.; Bonan, G. B.

    2014-07-01

    A growing body of literature documents the pressing need to develop soil biogeochemistry models that more accurately reflect contemporary understanding of soil processes and better capture soil carbon (C) responses to environmental perturbations. Models that explicitly represent microbial activity offer inroads to improve representations of soil biogeochemical processes, but have yet to consider relationships between litter quality, functional differences in microbial physiology, and the physical protection of microbial byproducts in forming stable soil organic matter (SOM). To address these limitations, we introduce the MIcrobial-MIneral Carbon Stabilization (MIMICS) model, and evaluate it by comparing site-level soil C projections with observations from a long-term litter decomposition study and soil warming experiment. In MIMICS, the turnover of litter and SOM pools is governed by temperature-sensitive Michaelis-Menten kinetics and the activity of two physiologically distinct microbial functional types. The production of microbial residues through microbial turnover provides inputs to SOM pools that are considered physically or chemically protected. Soil clay content determines the physical protection of SOM in different soil environments. MIMICS adequately simulates the mean rate of leaf litter decomposition observed at temperate and boreal forest sites, and captures observed effects of litter quality on decomposition rates. Moreover, MIMICS better captures the response of SOM pools to experimental warming, with rapid SOM losses but declining temperature sensitivity to long-term warming, compared with a more conventional model structure. MIMICS incorporates current microbial theory to explore the mechanisms by which litter C is converted to stable SOM, and to improve predictions of soil C responses to environmental change.

  6. Sharing Residual Liability

    DEFF Research Database (Denmark)

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    Economic models of tort law evaluate the efficiency of liability rules in terms of care and activity levels. A liability regime is optimal when it creates incentives to maximize the value of risky activities net of accident and precaution costs. The allocation of primary and residual liability...... the virtues and limits of loss-sharing rules in generating optimal (second-best) incentives and allocations of risk. We find that loss sharing may be optimal in the presence of countervailing policy objectives, homogeneous risk avoiders, and subadditive risk, which potentially offers a valuable tool...

  7. Microbial genome-wide association studies: lessons from human GWAS.

    Science.gov (United States)

    Power, Robert A; Parkhill, Julian; de Oliveira, Tulio

    2017-01-01

    The reduced costs of sequencing have led to whole-genome sequences for a large number of microorganisms, enabling the application of microbial genome-wide association studies (GWAS). Given the successes of human GWAS in understanding disease aetiology and identifying potential drug targets, microbial GWAS are likely to further advance our understanding of infectious diseases. These advances include insights into pressing global health problems, such as antibiotic resistance and disease transmission. In this Review, we outline the methodologies of GWAS, the current state of the field of microbial GWAS, and how lessons from human GWAS can direct the future of the field.

  8. Integrating microbial diversity in soil carbon dynamic models parameters

    Science.gov (United States)

    Louis, Benjamin; Menasseri-Aubry, Safya; Leterme, Philippe; Maron, Pierre-Alain; Viaud, Valérie

    2015-04-01

    Faced with the numerous concerns about soil carbon dynamic, a large quantity of carbon dynamic models has been developed during the last century. These models are mainly in the form of deterministic compartment models with carbon fluxes between compartments represented by ordinary differential equations. Nowadays, lots of them consider the microbial biomass as a compartment of the soil organic matter (carbon quantity). But the amount of microbial carbon is rarely used in the differential equations of the models as a limiting factor. Additionally, microbial diversity and community composition are mostly missing, although last advances in soil microbial analytical methods during the two past decades have shown that these characteristics play also a significant role in soil carbon dynamic. As soil microorganisms are essential drivers of soil carbon dynamic, the question about explicitly integrating their role have become a key issue in soil carbon dynamic models development. Some interesting attempts can be found and are dominated by the incorporation of several compartments of different groups of microbial biomass in terms of functional traits and/or biogeochemical compositions to integrate microbial diversity. However, these models are basically heuristic models in the sense that they are used to test hypotheses through simulations. They have rarely been confronted to real data and thus cannot be used to predict realistic situations. The objective of this work was to empirically integrate microbial diversity in a simple model of carbon dynamic through statistical modelling of the model parameters. This work is based on available experimental results coming from a French National Research Agency program called DIMIMOS. Briefly, 13C-labelled wheat residue has been incorporated into soils with different pedological characteristics and land use history. Then, the soils have been incubated during 104 days and labelled and non-labelled CO2 fluxes have been measured at ten

  9. Bioenergy from sisal residues

    Energy Technology Data Exchange (ETDEWEB)

    Jungersen, G. [Dansk Teknologisk Inst. (Denmark); Kivaisi, A.; Rubindamayugi, M. [Univ. of Dar es Salaam (Tanzania, United Republic of)

    1998-05-01

    The main objectives of this report are: To analyse the bioenergy potential of the Tanzanian agro-industries, with special emphasis on the Sisal industry, the largest producer of agro-industrial residues in Tanzania; and to upgrade the human capacity and research potential of the Applied Microbiology Unit at the University of Dar es Salaam, in order to ensure a scientific and technological support for future operation and implementation of biogas facilities and anaerobic water treatment systems. The experimental work on sisal residues contains the following issues: Optimal reactor set-up and performance; Pre-treatment methods for treatment of fibre fraction in order to increase the methane yield; Evaluation of the requirement for nutrient addition; Evaluation of the potential for bioethanol production from sisal bulbs. The processing of sisal leaves into dry fibres (decortication) has traditionally been done by the wet processing method, which consumes considerable quantities of water and produces large quantities of waste water. The Tanzania Sisal Authority (TSA) is now developing a dry decortication method, which consumes less water and produces a waste product with 12-15% TS, which is feasible for treatment in CSTR systems (Continously Stirred Tank Reactors). (EG)

  10. Multivariate analyses in soil microbial ecology : a new paradigm

    OpenAIRE

    Thioulouse, J.; Prin, Y.; Duponnois, Robin

    2012-01-01

    Mycorrhizal symbiosis is a key component of a sustainable soil-plant system, governing the cycles of major plant nutrients and vegetation cover. The mycorrhizosphere includes plants roots, the mycorrhizal fungi, and a complex microbial compartment. A large number of methods have been used to characterize the genetic and functional diversity of these soil microbial communities. We present here a review of the multivariate data analysis methods that have been used in 16 research articles publis...

  11. Short-term impact of dry olive mill residue addition to soil on the resident microbiota

    Czech Academy of Sciences Publication Activity Database

    Sampedro, I.; Giubilei, M. A.; Cajthaml, Tomáš; Federici, E.; Federici, F.; Petruccioli, M.; D´Annibale, A.

    2009-01-01

    Roč. 100, č. 23 (2009), s. 6098-6106 ISSN 0960-8524 R&D Projects: GA MŠk LC06066 Institutional research plan: CEZ:AV0Z50200510 Keywords : Dry olive mill residue * Microbial community profiling * Toxicity Subject RIV: EE - Microbiology, Virology Impact factor: 4.253, year: 2009

  12. Nouws antibiotics test: Validation of a post-screening method for antibiotic residues in kidney

    NARCIS (Netherlands)

    Pikkemaat, M.G.; Oostra-van Dijk, S.; Schouten, J.; Rapallini, M.; Kortenhoeven, L.; Egmond, van H.J.

    2009-01-01

    Anticipating the rise in ‘suspect’ samples caused by the introduction of a more sensitive screening test for the presence of antibiotic residues in slaughter animals, an additional microbial post-screening method was developed. The test comprises four antibiotic group specific test plates, optimized

  13. Nitrogen immobilization in plant growth substrates: clean chip residual, pine bark and peat moss

    Science.gov (United States)

    A study was undertaken to determine the extent of nitrogen (N) immobilization and microbial respiration in a high wood-fiber content substrate (clean chip residual (CCR)). Control treatments of pine bark (PB) and peat moss (PM) were compared to two screen sizes (0.95 cm and 0.48 cm) of CCR for micro...

  14. Limited recovery of soil microbial activity after transient exposure to gasoline vapors

    DEFF Research Database (Denmark)

    Modrzyński, Jakub J.; Christensen, Jan H.; Mayer, Philipp

    2016-01-01

    During gasoline spills complex mixtures of toxic volatile organic compounds (VOCs) are released to terrestrial environments. Gasoline VOCs exert baseline toxicity (narcosis) and may thus broadly affect soil biota. We assessed the functional resilience (i.e. resistance and recovery of microbial...... functions) in soil microbial communities transiently exposed to gasoline vapors by passive dosing via headspace for 40 days followed by a recovery phase of 84 days. Chemical exposure was characterized with GC-MS, whereas microbial activity was monitored as soil respiration (CO2 release) and soil bacterial...... microbial activity indicating residual soil toxicity, which could not be attributed to BTEX, but rather to mixture toxicity of more persistent gasoline constituents or degradation products. Our results indicate a limited potential for functional recovery of soil microbial communities after transient...

  15. Método de número mais provável para avaliação de grupos fisiológicos de microrganismos em digestão anaeróbia de água residuária de mandioca / Most probable number method for microorganism physiologic group's evaluation in anaerobic digestion of cassava wastewater

    Directory of Open Access Journals (Sweden)

    Maria Magdalena Ferreira Ribas

    2009-12-01

    ênico foi encontrado 103 microrganismos/mL no MC e 1015 microrganismos/mL no MM e uma contagem máxima de 1010 em MC. No efluente do reator metanogênico, foi encontrado 109 em MM microrganismos/mL e 1010 em MC. Para o MD, os valores foram intermediários para MC e MM em todas as amostras. Para testar a técnica de avaliação da atividade microbiana, uma dose única de choque de 750 mg/L de cianeto (CN- foi adicionada ao afluente do reator acidogênico. Depois de 48 horas, foi detectada redução na produção de gás e queda equivalente (104 no número de todos os grupos de microrganismos pela entrada do cianeto. A alimentação do reator foi retornada à concentração inicial de água residuária de processamento de mandioca e, depois de quinze dias o reator voltou a apresentar estabilidade. Em decorrência, observou-se aumento de todos os grupos de microrganismos. Portanto, as contagens microbianas obtidas foram condizentes com as condições de funcionamento dos reatores anaeróbios no período avaliado, validando a metodologia proposta.AbstractAbstractAnaerobic microbiology evaluation is an expensive and very difficult method. Simple techniques are available for the assessment of microorganism in several uses, such as medical, food, environment and anaerobic systems for wastewater treatment. A methodology was developed to assess the activity of microorganisms groups in anaerobic digestion with possible application to specific substrata. The technique applies oxygen-free gases in serum bottles closed with a rubber cover and an aluminum seal with the addition of a reducing indicator, nutrient complements and reducing agents after sterilization. The metabolism of the microorganisms was observed in these closed serum bottles after an incubation period of fourteen days, and regarding turbidness variation, pH variation measured by Arrhenius’s indicator and gas captured in Duran tubes. The Most Probable Number (MPN technique was used for microorganism counting in

  16. Microbial contaminants in Pakistan: a review

    Directory of Open Access Journals (Sweden)

    Maida Kanwal

    2016-04-01

    Full Text Available Worldwide contamination of surface waters with microbial pathogens is of substantial health concern. These contaminants are usually transmitted by improper sanitation measures, unsafe waste disposal, excretions from patients, and physical contacts, i.e., sexual and nonsexual. Majority of these microbial pathogens have been categorized into three classes, i.e., bacteria, viruses and protozoa. Pakistan, being a developing country, is facing a noteworthy threat due to microbial contamination. In Pakistan, bacterial contaminants are reported extensively followed by viral and protozoa contaminants. The health issues associated with bacterial population includes dysentery, abdominal pain, headache, diarrhea etc.; and usually includes faecal and total coliforms, E. coli, Salmonella, Shigella and Campylobacter. The cases related to viral contamination are lesser but chronic and evidenced the presence of HCV, HAV, HEV viruses causing hepatitis, and other hepatic disorders. Lastly, the health impacts associated with protozoans are least reported; and a number of diseases such as giardia, cryptosporidium and toxoplasma have been linked with this class of contaminants. The current review compiles information of these biological contaminants along with their health issues in Pakistan. Moreover, potential sources and fate of microbial contaminants are also discussed.

  17. A Microbial Assessment Scheme to measure microbial performance of Food Safety Management Systems.

    Science.gov (United States)

    Jacxsens, L; Kussaga, J; Luning, P A; Van der Spiegel, M; Devlieghere, F; Uyttendaele, M

    2009-08-31

    A Food Safety Management System (FSMS) implemented in a food processing industry is based on Good Hygienic Practices (GHP), Hazard Analysis Critical Control Point (HACCP) principles and should address both food safety control and assurance activities in order to guarantee food safety. One of the most emerging challenges is to assess the performance of a present FSMS. The objective of this work is to explain the development of a Microbial Assessment Scheme (MAS) as a tool for a systematic analysis of microbial counts in order to assess the current microbial performance of an implemented FSMS. It is assumed that low numbers of microorganisms and small variations in microbial counts indicate an effective FSMS. The MAS is a procedure that defines the identification of critical sampling locations, the selection of microbiological parameters, the assessment of sampling frequency, the selection of sampling method and method of analysis, and finally data processing and interpretation. Based on the MAS assessment, microbial safety level profiles can be derived, indicating which microorganisms and to what extent they contribute to food safety for a specific food processing company. The MAS concept is illustrated with a case study in the pork processing industry, where ready-to-eat meat products are produced (cured, cooked ham and cured, dried bacon).

  18. Characteristics of purple nonsulfur bacteria grown under Stevia residue extractions.

    Science.gov (United States)

    Xu, J; Feng, Y; Wang, Y; Lin, X

    2013-11-01

    As a consequence of the large-scale cultivation of Stevia plants, releases of plant residues, the byproduct after sweetener extraction, to the environment are inevitable. Stevia residue and its effluent after batching up contain large amounts of organic matters with small molecular weight, which therefore are a potential pollution source. Meanwhile, they are favourite substrates for micro-organism growths. This investigation was aimed to utilize the simulated effluent of Stevia residue to enrich the representative purple nonsulfur bacterium (PNSB), Rhodopseudomonas palustris (Rps. palustris), which has important economic values. The growth profile and quality of Rps. palustris were characterized by spectrophotometry, compared to those grown in common PNSB mineral synthetic medium. Our results revealed that the simulated effluent of Stevia residue not only stimulated Rps. palustris growth to a greater extent, but also increased its physiologically active cytochrome concentrations and excreted indole-3-acetic acid (IAA) content. This variation in phenotype of Rps. palustris could result from the shift in its genotype, further revealed by the repetitive sequence-based PCR (rep-PCR) fingerprinting analysis. Our results showed that the effluent of Stevia residue was a promising substrate for microbial growth. © 2013 The Society for Applied Microbiology.

  19. Contribution of the thraustochytrid Corallochytrium limacisporum Raghu-kumar to microbial biomass in coral reef lagoons

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, S.; Chandramohan, D.; Ramaiah, N.

    on the number of C limacisporum, total viable bacteria (saprophyte numbers), chlorophyll a content and total ATP in the lagoon waters, the contribution of C limacisporum to the microbial biomass in coral reef lagoons of the Lakshadweep islands was calculated...

  20. Microbial Risk Assessment

    Science.gov (United States)

    Ott, C. M.; Mena, K. D.; Nickerson, C.A.; Pierson, D. L.

    2009-01-01

    Historically, microbiological spaceflight requirements have been established in a subjective manner based upon expert opinion of both environmental and clinical monitoring results and the incidence of disease. The limited amount of data, especially from long-duration missions, has created very conservative requirements based primarily on the concentration of microorganisms. Periodic reevaluations of new data from later missions have allowed some relaxation of these stringent requirements. However, the requirements remain very conservative and subjective in nature, and the risk of crew illness due to infectious microorganisms is not well defined. The use of modeling techniques for microbial risk has been applied in the food and potable water industries and has exceptional potential for spaceflight applications. From a productivity standpoint, this type of modeling can (1) decrease unnecessary costs and resource usage and (2) prevent inadequate or inappropriate data for health assessment. In addition, a quantitative model has several advantages for risk management and communication. By identifying the variable components of the model and the knowledge associated with each component, this type of modeling can: (1) Systematically identify and close knowledge gaps, (2) Systematically identify acceptable and unacceptable risks, (3) Improve communication with stakeholders as to the reasons for resource use, and (4) Facilitate external scientific approval of the NASA requirements. The modeling of microbial risk involves the evaluation of several key factors including hazard identification, crew exposure assessment, dose-response assessment, and risk characterization. Many of these factors are similar to conditions found on Earth; however, the spaceflight environment is very specialized as the inhabitants live in a small, semi-closed environment that is often dependent on regenerative life support systems. To further complicate modeling efforts, microbial dose

  1. Microbial field pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1992-03-01

    The objective of this project is to perform a microbial enhanced oil recovery field pilot in the Southeast Vassar Vertz Sand Unit (SEVVSU) in Payne County, Oklahoma. Indigenous, anaerobic, nitrate reducing bacteria will be stimulated to selectively plug flow paths which have been referentially swept by a prior waterflood. This will force future flood water to invade bypassed regions of the reservoir and increase sweep efficiency. This report covers progress made during the second year, January 1, 1990 to December 31, 1990, of the Microbial Field Pilot Study project. Information on reservoir ecology, surface facilities design, operation of the unit, core experiments, modeling of microbial processes, and reservoir characterization and simulation are presented in the report. To better understand the ecology of the target reservoir, additional analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. The results of the produced and injected water analysis show increasing sulfide concentrations with respect to time. In March of 1990 Mesa Limited Partnership sold their interest in the SEVVSU to Sullivan and Company. In April, Sullivan and Company assumed operation of the field. The facilities for the field operation of the pilot were refined and implementation was begun. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. The experiments were performed at SEVVSU temperature using fluids and inoculum from the unit. The model described in last year's report was further validated using results from a core flood experiment. The model was able to simulate the results of one of the core flood experiments with good quality.

  2. Microbial field pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1992-03-01

    The objective of this project is to perform a microbial enhanced oil recovery field pilot in the Southeast Vassar Vertz Sand Unit (SEVVSU) in Payne County, Oklahoma. Indigenous, anaerobic, nitrate reducing bacteria will be stimulated to selectively plug flow paths which have been referentially swept by a prior waterflood. This will force future flood water to invade bypassed regions of the reservoir and increase sweep efficiency. This report covers progress made during the second year, January 1, 1990 to December 31, 1990, of the Microbial Field Pilot Study project. Information on reservoir ecology, surface facilities design, operation of the unit, core experiments, modeling of microbial processes, and reservoir characterization and simulation are presented in the report. To better understand the ecology of the target reservoir, additional analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. The results of the produced and injected water analysis show increasing sulfide concentrations with respect to time. In March of 1990 Mesa Limited Partnership sold their interest in the SEVVSU to Sullivan and Company. In April, Sullivan and Company assumed operation of the field. The facilities for the field operation of the pilot were refined and implementation was begun. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. The experiments were performed at SEVVSU temperature using fluids and inoculum from the unit. The model described in last year`s report was further validated using results from a core flood experiment. The model was able to simulate the results of one of the core flood experiments with good quality.

  3. Microbial Glycosidases for Nondigestible

    DEFF Research Database (Denmark)

    Bezerra, Thais; Montibra, Rubens; Hansen, Egon Bech

    2017-01-01

    There is much interest in the study and production of nondigestible oligosaccharides (NDOs), due to their bioactivities and beneficial effects to the human health. The main approach in the production of NDOs relies on the action of glycosidases performing hydrolysis or transglycosylation of polys...... of polysaccharides and sugars. In this chapter, a description of the main microbial glycosidases used for NDOs production, their sources, their principal properties, and a description of the production processes with the better results obtained are discussed....

  4. Dissecting and analyzing key residues in protein-DNA complexes.

    Science.gov (United States)

    Kulandaisamy, A; Srivastava, Ambuj; Nagarajan, R; Gromiha, M Michael

    2018-04-01

    Protein-DNA interactions are involved in various fundamental biological processes such as replication, transcription, DNA repair, and gene regulation. To understand the interaction in protein-DNA complexes, the integrative study of binding and stabilizing residues is important. In the present study, we have identified key residues that play a dual role in both binding and stability from a nonredundant dataset of 319 protein-DNA complexes. We observed that key residues are identified in very less number of complexes (29%) and only about 4% of stabilizing/binding residues are identified as key residues. Specifically, stabilizing residues have higher preference to be key residues than binding residues. These key residues include polar, nonpolar, aliphatic, aromatic, and charged amino acids. Moreover, we have analyzed and discussed the key residues in different protein-DNA complexes, which are classified based on protein structural class, function, DNA strand, and their conformations. Especially, Ser, Thr, Tyr, Arg, and Lys residues are commonly found in most of the subclasses of protein-DNA complexes. Further, we analyzed atomic contacts, which show that polar-nonpolar is more enriched than other types of contacts. In addition, the charged contacts are highly preferred in protein-DNA complexes compared with protein-protein and protein-RNA complexes. Finally, we have discussed the sequence and structural features of key residues such as conservation score, surrounding hydrophobicity, solvent accessibility, secondary structure, and long-range order. This study will be helpful to understand the recognition mechanism and structural and functional aspects of protein-DNA complexes. Copyright © 2017 John Wiley & Sons, Ltd.

  5. Stabilization of microbial biomass in soils: Implications for SOM formation and xenobiotics degradation

    Science.gov (United States)

    Miltner, A.; Kindler, R.; Achtenhagen, J.; Nowak, K.; Girardi, C.; Kästner, M.

    2012-04-01

    Soil organic matter (SOM) plays an important role in soils. It is the carbon source and the habitat of many soil microorganisms, its quality and quantity thus affect soil microbial activity. Therefore, the amount and composition of SOM determines soil quality, but SOM formation and stabilization are not yet sufficiently understood. Recently, microbial biomass residues could be identified as a significant source of SOM. We incubated 13C-labelled bacterial cells for 224 days in an agricultural soil and traced the fate of the 13C label of bacterial biomass in soil by isotopic analysis. The data were combined to a mass balance, and the biomass residues were visualized by scanning electron microscopy (SEM). A high percentage of the biomass-derived carbon (in particular from proteins) remained in soil, mainly in the non-living part of SOM, after extended incubation. The SEM micrographs only rarely showed intact cells. Instead, organic patchy fragments of 200-500 nm size were abundant. These fragments were associated with all stages of cell envelope decay and fragmentation, indicating specific disintegration processes of cell walls. Similar fragments developed on initially clean and sterile in situ microcosms during exposure in groundwater, thus providing clear evidence for their microbial origin. Microbial cell envelope fragments thus contribute significantly to SOM formation. A significant contribution of cell envelope fragments to SOM formation provides a simple explanation for the development of the small, nano-scale patchy organic materials observed in soil electron micrographs. It also suggests that microstructures of microbial cells and of small plant debris provide the molecular architecture of SOM attached to particle surfaces. This origin and macromolecular architecture of SOM is consistent with most observations on SOM, e.g. the abundance of microbial-derived biomarkers, the low C/N ratio, the water repellency and the stabilization of microbial biomass. The

  6. Pathogenesis of microbial keratitis.

    Science.gov (United States)

    Lakhundi, Sahreena; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2017-03-01

    Microbial keratitis is a sight-threatening ocular infection caused by bacteria, fungi, and protist pathogens. Epithelial defects and injuries are key predisposing factors making the eye susceptible to corneal pathogens. Among bacterial pathogens, the most common agents responsible for keratitis include Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumonia and Serratia species. Fungal agents of corneal infections include both filamentous as well as yeast, including Fusarium, Aspergillus, Phaeohyphomycetes, Curvularia, Paecilomyces, Scedosporium and Candida species, while in protists, Acanthamoeba spp. are responsible for causing ocular disease. Clinical features include redness, pain, tearing, blur vision and inflammation but symptoms vary depending on the causative agent. The underlying molecular mechanisms associated with microbial pathogenesis include virulence factors as well as the host factors that aid in the progression of keratitis, resulting in damage to the ocular tissue. The treatment therefore should focus not only on the elimination of the culprit but also on the neutralization of virulence factors to minimize the damage, in addition to repairing the damaged tissue. A complete understanding of the pathogenesis of microbial keratitis will lead to the rational development of therapeutic interventions. This is a timely review of our current understanding of the advances made in this field in a comprehensible manner. Coupled with the recently available genome sequence information and high throughput genomics technology, and the availability of innovative approaches, this will stimulate interest in this field. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Nanoporous microscale microbial incubators.

    Science.gov (United States)

    Ge, Zhifei; Girguis, Peter R; Buie, Cullen R

    2016-02-07

    Reconstruction of phylogenetic trees based on 16S rRNA gene sequencing reveals abundant microbial diversity that has not been cultured in the laboratory. Many attribute this so-called 'great plate count anomaly' to traditional microbial cultivation techniques, which largely facilitate the growth of a single species. Yet, it is widely recognized that bacteria in nature exist in complex communities. One technique to increase the pool of cultivated bacterial species is to co-culture multiple species in a simulated natural environment. Here, we present nanoporous microscale microbial incubators (NMMI) that enable high-throughput screening and real-time observation of multi-species co-culture. The key innovation in NMMI is that they facilitate inter-species communication while maintaining physical isolation between species, which is ideal for genomic analysis. Co-culture of a quorum sensing pair demonstrates that the NMMI can be used to culture multiple species in chemical communication while monitoring the growth dynamics of individual species.

  8. CHARACTERISTICS OF COMPOSTED BIO-TOILET RESIDUE AND ITS POTENTIAL USE AS A SOIL CONDITIONER

    Directory of Open Access Journals (Sweden)

    Jovita Triastuti

    2016-10-01

    /N ratio 27, and contained N, P, K, and Na of 1.73, 1.15, 1.03, and 0.88%, respectively. Its microbial count showed only two kinds of bacteria, i.e., Klebsiella pneumonia and Escherichia coli, detected at 14 and 122 days of bio-toilet usage. The composted bio-toilet residue improved vegetative performances of J. curcas as indicated by increasing leaf number, leaf area, stem height, and stem diameter.

  9. Allee effect: the story behind the stabilization or extinction of microbial ecosystem.

    Science.gov (United States)

    Goswami, Madhurankhi; Bhattacharyya, Purnita; Tribedi, Prosun

    2017-03-01

    A population exhibiting Allee effect shows a positive correlation between population fitness and population size or density. Allee effect decides the extinction or conservation of a microbial population and thus appears to be an important criterion in population ecology. The underlying factor of Allee effect that decides the stabilization and extinction of a particular population density is the threshold or the critical density of their abundance. According to Allee, microbial populations exhibit a definite, critical or threshold density, beyond which the population fitness of a particular population increases with the rise in population density and below it, the population fitness goes down with the decrease in population density. In particular, microbial population displays advantageous traits such as biofilm formation, expression of virulence genes, spore formation and many more only at a high population density. It has also been observed that microorganisms exhibiting a lower population density undergo complete extinction from the residual microbial ecosystem. In reference to Allee effect, decrease in population density or size introduces deleterious mutations among the population density through genetic drift. Mutations are carried forward to successive generations resulting in its accumulation among the population density thus reducing its microbial fitness and thereby increasing the risk of extinction of a particular microbial population. However, when the microbial load is high, the chance of genetic drift is less, and through the process of biofilm formation, the cooperation existing among the microbial population increases that increases the microbial fitness. Thus, the high microbial population through the formation of microbial biofilm stabilizes the ecosystem by increasing fitness. Taken together, microbial fitness shows positive correlation with the ecosystem conservation and negative correlation with ecosystem extinction.

  10. Marine Tar Residues: a Review

    OpenAIRE

    Warnock, April M.; Hagen, Scott C.; Passeri, Davina L.

    2015-01-01

    Marine tar residues originate from natural and anthropogenic oil releases into the ocean environment and are formed after liquid petroleum is transformed by weathering, sedimentation, and other processes. Tar balls, tar mats, and tar patties are common examples of marine tar residues and can range in size from millimeters in diameter (tar balls) to several meters in length and width (tar mats). These residues can remain in the ocean environment indefinitely, decomposing or becoming buried in ...

  11. Number Sense on the Number Line

    Science.gov (United States)

    Woods, Dawn Marie; Ketterlin Geller, Leanne; Basaraba, Deni

    2018-01-01

    A strong foundation in early number concepts is critical for students' future success in mathematics. Research suggests that visual representations, like a number line, support students' development of number sense by helping them create a mental representation of the order and magnitude of numbers. In addition, explicitly sequencing instruction…

  12. The earthworm gastrointestinal effect on the release of organic bound residues in soils

    Science.gov (United States)

    Du, J. H.

    2018-03-01

    Earthworm activities promote the release of bound residues and the digestive activities of earthworms contribute to the process. Earthworm digestive effects on bound residues can be divided into physical and chemical effects. Physical effects include gastrointestinal abrasion and mixing. The abrasion of soil and litter residues in earthworm gizzards and intestine can grind the food into fine particles, which increase the contact surface with microbial and promote the desorption of bound residues. Chemical effects are attributed to the secreted surfactant substances and digestive enzymes. The surfactants, especially at levels that lead to micellization, can enhance the desorption process of the organic contaminants that sored in the soil. The enzymes in earthworm digestive tracts can decompose the humus in soil, which may promote the release of organic residues that bind with humus.

  13. Metal-containing residues from industry and in the environment: geobiotechnological urban mining.

    Science.gov (United States)

    Glombitza, Franz; Reichel, Susan

    2014-01-01

    This chapter explains the manifold geobiotechnological possibilities to separate industrial valuable metals from various industrial residues and stored waste products of the past. In addition to an overview of the different microbially catalyzed chemical reactions applicable for a separation of metals and details of published studies, results of many individual investigations from various research projects are described. These concern the separation of rare earth elements from phosphorous production slags, the attempts of tin leaching from mining flotation residues, the separation of metals from spent catalysts, or the treatment of ashes as valuable metal-containing material. The residues of environmental technologies are integrated into this overview as well. The description of the different known microbial processes offers starting points for suitable and new technologies. In addition to the application of chemolithoautotrophic microorganisms the use of heterotrophic microorganisms is explained.

  14. The Role of the Horizontal Gene Pool and Lateral Gene Transfer in Enhancing Microbial Activities in Marine Sediments

    National Research Council Canada - National Science Library

    Sobecky, Patricia A

    2006-01-01

    To better understand plasmid distribution, diversity and abundance in marine sediment microbial communities we developed a number of methodological approaches to advance the field during this project...

  15. Microbial Repopulation Following In Situ STAR Remediation

    Science.gov (United States)

    Gerhard, J.; Overbeeke, G.; Edwards, E.; Lomheim, L.; Grant, G.

    2016-12-01

    STAR (Self-sustaining Treatment for Active Remediation) is an emerging remediation technology that employs a self-sustaining smouldering reaction to destroy nonaqueous phase liquids (NAPLs) in the subsurface. The reaction front travels outwards from an ignition well at approximately 0.5 per day and subjects the soil to temperatures of 400°C-1000°C. The objectives of this work were to monitor re-saturation of the soil over time and quantify the microbial repopulation of the treated zone. STAR is currently being applied as a full scale, in situ remedy for coal tar beneath a former creosol manufacturing facility in New Jersey, USA. This study analyzed soil cores taken at regular intervals following STAR treatment, allowing time for groundwater to re-infiltrate and for microbial populations to potentially reestablish. Soil and groundwater were analyzed for total number of microorganisms via quantitative Polymerase Chain Reaction (qPCR), as well as microbial diversity via amplicon sequencing. Results demonstrate that microbes rapidly repopulated over a 2 month period to 106 gene copies/g of soil. However, concentrations in the treated zone did not rise above this concentration over 6 months post-STAR, indicating a low carrying capacity of the treated soil. To examine the system in more detail and consider the effects of bio-stimulation, a bench top column study using site soil and artificial groundwater explored the rate at which STAR-treated soil is repopulated with naturally occurring microorganisms in the presence and absence of lactate and a terminal electron acceptor. Results demonstrated that biostimulation did not increase the carrying capacity of the STAR treated sol, but rather shifted the microbial community to reflect the TEA provided, in this case, promoting sulfate reducers. Overall, the work illustrates that microbial populations in STAR treated soil do recover via groundwater infiltration but robust communities will take time to naturally establish.

  16. Control of Pecan Weevil With Microbial Biopesticides.

    Science.gov (United States)

    Shapiro-Ilan, David I; Cottrell, Ted E; Bock, Clive; Mai, Kim; Boykin, Debbie; Wells, Lenny; Hudson, William G; Mizell, Russell F

    2017-12-08

    The pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae), is a key pest of pecans Carya illinoinensis ([Wangenh.] K. Koch) (Fagales: Juglandaceae). Control recommendations rely on broad spectrum chemical insecticides. Due to regulatory and environmental concerns, effective alternatives for C. caryae control must be sought for pecan production in conventional and organic systems. We explored the use of microbial biopesticides for control of C. caryae in Georgia pecan orchards. Three experiments were conducted. The first investigated an integrated microbial control approach in an organic system at two locations. Three microbial agents, Grandevo (based on byproducts of the bacterium Chromobacterium subtsugae Martin, Gundersen-Rindal, Blackburn & Buyer), the entomopathogenic nematode Steinernema carpocapsae (Weiser), and entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin, were applied to each treatment plot (0.6 ha) at different times during the season. A second experiment compared the effects of S. carpocapsae and B. bassiana applied as single treatments relative to application of both agents (at different times); survival of C. caryae was assessed approximately 11 mo after larvae were added to pots sunk in an organic pecan orchard. In a conventional orchard (with 1.0 ha plots), the third experiment compared Grandevo applications to a commonly used regime of chemical insecticides (carbaryl alternated with a pyrethroid). All experiments were repeated in consecutive years. The combined pest management tactic (experiment 1) reduced C. caryae infestation relative to non-treated control plots in both locations in 2014 and one of the two locations in 2015 (the other location had less than 1% infestation). In experiment 2, no differences among combined microbial treatments, single-applied microbial treatments or different numbers of application were observed, yet all microbial treatments reduced C. caryae survival relative to the control. In the third

  17. Evaluation of residue-residue contact predictions in CASP9

    KAUST Repository

    Monastyrskyy, Bohdan

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures being the precision in recognizing contacts and the difference between the distribution of distances in the subset of predicted contact pairs versus all pairs of residues in the structure. The emphasis is placed on the prediction of long-range contacts (i.e., contacts between residues separated by at least 24 residues along sequence) in target proteins that cannot be easily modeled by homology. Although there is considerable activity in the field, the current analysis reports no discernable progress since CASP8.

  18. When microbial conversations get physical

    OpenAIRE

    Reguera, Gemma

    2011-01-01

    It is widely accepted that microorganisms are social beings. Whereas communication via chemical signals (e.g. quorum sensing) has been the focus of most investigations, the use of physical signals for microbial cell-cell communication has received only limited attention. Here, I argue that physical modes of microbial communication could be widespread in nature. This is based on experimental evidence on the microbial emission and response to three physical signals: sound waves, electromagnetic...

  19. Microbial ecology of phototrophic biofilms

    OpenAIRE

    Roeselers, G.

    2007-01-01

    Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic biofilms can best be defined as surface attached microbial communities mainly driven by light as the energy source with a photosynthesizing component clearly present. Eukaryotic algae and cyanobact...

  20. Microbial lipases: Production, properties and biotechnological applications

    Directory of Open Access Journals (Sweden)

    Josana Maria Messias

    2011-09-01

    Full Text Available Lipases belong to the group of hydrolases that catalyze the hydrolysis of triacylglycerol lipids to free fatty acids and glycerol. They have significant potential biotechnological applications in catalyzing organic synthesis reactions in non-aqueous solvents using simplified procedures resulting in conversions of high yields. Lipase production has conventionally been performed by submerged fermentation; however, solid-state fermentation processes have been prominent when residues are used as substrates because they serve as low-cost nutrient sources. Microbial lipases can be used as additives in foods to modify and enhance organoleptic properties, as well as in detergents to hydrolyse fats in the treatment of oily effluents, and also have value for pharmaceutical, cosmetic, agrochemical, and oil chemical industries. More recently, they are used in transesterification reactions to convert plant seed oils into biodiesel. The objective of this work was to review the published literature on the production, properties and applications of microbial lipases, and its biotechnological role in producing biodiesel.

  1. Factors Affecting Microbial Contamination of Market Eggs: A Review

    Directory of Open Access Journals (Sweden)

    Svobodová J.

    2015-01-01

    Full Text Available The aim of the review was to analyze the ways of microbial contamination, the protective mechanism of egg, and factors that affect the quantity of contamination and microbial penetration. Eggs can be contaminated during their formation in the infected reproductive organs of hens or after laying, when eggs are exposed to contaminated environment. The eggs are equipped against microbial contamination by several protective mechanisms comprising the presence of cuticle, eggshell, eggshell membranes, occurrence of some antibacterial proteins, and high pH value of albumen. There are several factors that affect the quantity of microbial contamination and penetration such as species of bacteria, the amount of microorganisms, storage conditions, quality of eggshell or number of pores.

  2. Sequencing intractable DNA to close microbial genomes.

    Directory of Open Access Journals (Sweden)

    Richard A Hurt

    Full Text Available Advancement in high throughput DNA sequencing technologies has supported a rapid proliferation of microbial genome sequencing projects, providing the genetic blueprint for in-depth studies. Oftentimes, difficult to sequence regions in microbial genomes are ruled "intractable" resulting in a growing number of genomes with sequence gaps deposited in databases. A procedure was developed to sequence such problematic regions in the "non-contiguous finished" Desulfovibrio desulfuricans ND132 genome (6 intractable gaps and the Desulfovibrio africanus genome (1 intractable gap. The polynucleotides surrounding each gap formed GC rich secondary structures making the regions refractory to amplification and sequencing. Strand-displacing DNA polymerases used in concert with a novel ramped PCR extension cycle supported amplification and closure of all gap regions in both genomes. The developed procedures support accurate gene annotation, and provide a step-wise method that reduces the effort required for genome finishing.

  3. Microbial Cell Dynamics Lab (MCDL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Microbial Cell Dynamics Laboratory at PNNL enables scientists to study the molecular details of microbes under relevant environmental conditions. The MCDL seeks...

  4. Volume 9 Number 1

    African Journals Online (AJOL)

    OLUWOLE

    no doubt exposes the food stuff to dust particles from moving vehicles, wind and other sources. Thus, fungal spores from the air ... contact with food to reduce microbial contamination and also to avoid other unhygienic handling of locally marketed foods. ... riboflavin, thiamin, nicotinic acid, citrate, with low iron and vitamin ...

  5. Distribution of squares modulo a composite number

    OpenAIRE

    Aryan, Farzad

    2015-01-01

    In this paper we study the distribution of squares modulo a square-free number $q$. We also look at inverse questions for the large sieve in the distribution aspect and we make improvements on existing results on the distribution of $s$-tuples of reduced residues.

  6. Landfilling of waste incineration residues

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Astrup, Thomas; Cai, Zuansi

    2002-01-01

    Residues from waste incineration are bottom ashes and air-pollution-control (APC) residues including fly ashes. The leaching of heavy metals and salts from the ashes is substantial and a wide spectrum of leaching tests and corresponding criteria have been introduced to regulate the landfilling...

  7. Microbial field pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Coates, J.D.; Chisholm, J.L.

    1993-05-01

    A multi-well microbially enhanced oil recovery field pilot has been performed in the Southeast Vassar Vertz Sand Unit in Payne County, Oklahoma. The primary emphasis of the experiment was preferential plugging of high permeability zones for the purpose of improving waterflood sweep efficiency. Studies were performed to determine reservoir chemistry, ecology, and indigenous bacteria populations. Growth experiments were used to select a nutrient system compatible with the reservoir that encouraged growth of a group of indigenous nitrate-using bacteria and inhibit growth of sulfate-reducing bacteria. A specific field pilot area behind an active line drive waterflood was selected. Surface facilities were designed and installed. Injection protocols of bulk nutrient materials were prepared to facilitate uniform distribution of nutrients within the pilot area. By the end of December, 1991, 82.5 tons (75.0 tonnes) of nutrients had been injected in the field. A tracer test identified significant heterogeneity in the SEVVSU and made it necessary to monitor additional production wells in the field. The tracer tests and changes in production behavior indicate the additional production wells monitored during the field trial were also affected. Eighty two and one half barrels (13.1 m[sup 3]) of tertiary oil have been recovered. Microbial activity has increased CO[sub 2] content as indicated by increased alkalinity. A temporary rise in sulfide concentration was experienced. These indicate an active microbial community was generated in the field by the nutrient injection. Pilot area interwell pressure interference test results showed that significant permeability reduction occurred. The interwell permeabilities in the pilot area between the injector and the three pilot production wells were made more uniform which indicates a successful preferential plugging enhanced oil recovery project.

  8. Microbial lipid production from SPORL-pretreated Douglas fir by Mortierella isabellina

    Science.gov (United States)

    S.M. Harde; Z. Wang; M. Horne; Junyong Zhu; X. Pan

    2016-01-01

    The solid substrate and spent liquo robtained after SPORL pretreatment of Douglas fir residues were evaluated as substrates for the production of intracellular microbial lipid by Mortierella isabellina NRRL 1757. The production of lipid was investigated in a batch fermentation using different strategies viz. separate hydrolysis...

  9. Statistical inference on residual life

    CERN Document Server

    Jeong, Jong-Hyeon

    2014-01-01

    This is a monograph on the concept of residual life, which is an alternative summary measure of time-to-event data, or survival data. The mean residual life has been used for many years under the name of life expectancy, so it is a natural concept for summarizing survival or reliability data. It is also more interpretable than the popular hazard function, especially for communications between patients and physicians regarding the efficacy of a new drug in the medical field. This book reviews existing statistical methods to infer the residual life distribution. The review and comparison includes existing inference methods for mean and median, or quantile, residual life analysis through medical data examples. The concept of the residual life is also extended to competing risks analysis. The targeted audience includes biostatisticians, graduate students, and PhD (bio)statisticians. Knowledge in survival analysis at an introductory graduate level is advisable prior to reading this book.

  10. Microbial bebop: creating music from complex dynamics in microbial ecology.

    Science.gov (United States)

    Larsen, Peter; Gilbert, Jack

    2013-01-01

    In order for society to make effective policy decisions on complex and far-reaching subjects, such as appropriate responses to global climate change, scientists must effectively communicate complex results to the non-scientifically specialized public. However, there are few ways however to transform highly complicated scientific data into formats that are engaging to the general community. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated Microbial Bebop, a method by which microbial environmental data are transformed into music. Microbial Bebop uses meter, pitch, duration, and harmony to highlight the relationships between multiple data types in complex biological datasets. We use a comprehensive microbial ecology, time course dataset collected at the L4 marine monitoring station in the Western English Channel as an example of microbial ecological data that can be transformed into music. Four compositions were generated (www.bio.anl.gov/MicrobialBebop.htm.) from L4 Station data using Microbial Bebop. Each composition, though deriving from the same dataset, is created to highlight different relationships between environmental conditions and microbial community structure. The approach presented here can be applied to a wide variety of complex biological datasets.

  11. [Calculating Pearson residual in logistic regressions: a comparison between SPSS and SAS].

    Science.gov (United States)

    Xu, Hao; Zhang, Tao; Li, Xiao-song; Liu, Yuan-yuan

    2015-01-01

    To compare the results of Pearson residual calculations in logistic regression models using SPSS and SAS. We reviewed Pearson residual calculation methods, and used two sets of data to test logistic models constructed by SPSS and STATA. One model contained a small number of covariates compared to the number of observed. The other contained a similar number of covariates as the number of observed. The two software packages produced similar Pearson residual estimates when the models contained a similar number of covariates as the number of observed, but the results differed when the number of observed was much greater than the number of covariates. The two software packages produce different results of Pearson residuals, especially when the models contain a small number of covariates. Further studies are warranted.

  12. Síntese de proteína microbiana em bovinos alimentados com resíduos de mandioca e cana-de-açúcar ensilados com polpa cítrica Efficiency of microbial protein in bovine fed with cassava residues and sugar cane ensiled with citric pulp

    Directory of Open Access Journals (Sweden)

    Ana Karina Dias Salman

    2002-04-01

    Full Text Available Objetivando-se estudar a síntese de proteína microbiana em bovinos, quatro animais canulados no rúmen e duodeno foram alimentados com 4 dietas: 1- Dieta basal (DB, composta por silagem de milho (SMi e farelo de soja participando na proporção de 60% da matéria seca total das dietas à base de casca e raspa de mandioca; 2- DB + silagem de raspa de mandioca (SRp; 3- DB + silagem de casca de mandioca (SCc e 4- silagem de cana-de-açúcar (SCn, sendo as silagens SRp, SCc e SCn acrescidas da polpa cítrica peletizada como aditivo. O delineamento utilizado foi o quadrado latino 4x4. Não houve diferença (P > 0,05 em relação à composição das bactérias isoladas do conteúdo ruminal de animais que recebiam as diferentes dietas. A eficiência de síntese de proteína microbiana das dietas com SMi, SRp e SCc foram maiores (P With the goal to study the microbial protein synthesis in bovines, four duodenal and ruminant canuleted animals were arranged in a 4 x 4 Latin square and fed with diets formulated with: corn (CS, cassava meal (CMS, cassava hull (CHS or sugar cane (SCS silage. The CMS, CHS and SCS were mixed with citric pulp. The basal diet, composed by CS and soybean meal, participated in 60% of total dry matter of cassava diets. There was no difference (p > 0.05 among diets in relation to bacterial composition isolated from the animal's ruminant contents. The efficiency of microbial protein synthesis of diets on CS, CMS and CHS were larger (p < 0.05 (32.1; 22.2; 26.1 gN/kg of organic matter apparently rumen degraded, respectively than CS (16.4 gN/kg OMARD.

  13. [Microbial sources of pigments].

    Science.gov (United States)

    Cañizares-Villanueva, R O; Ríos-Leal, E; Olvera Ramírez, R; Ponce Noyola, T; Márquez Rocha, F

    1998-01-01

    Pigments from natural sources has been obtained since long time ago, and their interest has increased due to the toxicity problems caused by those of synthetic origin. In this way the pigments from microbial sources are a good alternative. Some of more important natural pigments, are the carotenoids, flavonoids (anthocyanins) and some tetrapirroles (chloropyls, phycobilliproteins). Another group less important are the betalains and quinones. The carotenoids are molecules formed by isoprenoids units and the most important used as colorant are the alpha and beta carotene which are precursors of vitamin A, and some xantophylls as astaxanthin. The pigment more used in the industry is the beta-carotene which is obtained from some microalgae and cyanobacteria. The astaxanthin another important carotenoid is a red pigment of great commercial value, and it is used in the pharmaceutical feed and acuaculture industries. This pigments is mainly obtained from Phaffia rhodozyma and Haematococcus pluvialis and other organisms. The phycobilliproteins obtained from cyanobacteria and some group of algae, have recently been increased on the food industries. In the last years it has been used as fluorescent marker in biochemical assays. Our research group have carried out studies about the factors that improve the production of these pigments obtained from different microbial species as well as the methods for their extraction and application.

  14. Cycling of fertilizer and cotton crop residue nitrogen

    International Nuclear Information System (INIS)

    Rochester, I.J.; Constable, G.A.; MacLeod, D.A.

    1993-01-01

    Mineral nitrogen (N), nitrate and ammonium contents were monitored in N-fertilized soils supporting cotton crops to provide information on the nitrification, mineralization and immobilization processes operating in the soil. The relative contributions of fertilizer N, previous cotton crop residue N and indigenous soil N to the mineral N pools and to the current crop's N uptake were calculated. After N fertilizer (urea) application, the soil's mineral N content rose rapidly and subsequently declined at a slower rate. The recovery of 15 N-labelled urea as mineral N declined exponentially with time. Biological immobilization (and possibly denitrification to some extent) were believed to be the major processes reducing post-application soil mineral N content. Progressively less N was mineralized upon incubation of soil sampled through the growing season. Little soil N (either from urea or crop residue) was mineralized at crop maturity. Cycling of N was evident between the soil mineral and organic N pools throughout the cotton growing season. Considerable quantities of fertilizer N were immobilized by the soil micro biomass; immobilized N was remineralized and subsequently taken up by the cotton crop. A large proportion of the crop N was taken up in the latter part of the season when the soil mineral N content was low. It is suggested that much of the N taken up by cotton was derived from microbial sources, rather than crop residues. The application of cotton crop residue (stubble) slightly reduced the mineral N content in the soil by encouraging biological immobilization. 15 N was mineralized very slowly from the labelled crop residue and did not contribute significantly to the supply of N to the current crop. Recovery of labelled fertilizer N and labelled crop residue N by the cotton crop was 28% and 1%, respectively. In comparison, the apparent recovery of fertilizer N was 48%. Indigenous soil N contributed 68% of the N taken up by the cotton crop. 33 refs., 1 tab

  15. Microbial ecology of phototrophic biofilms

    NARCIS (Netherlands)

    Roeselers, G.

    2007-01-01

    Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic

  16. Advances in microbial steroid biotransformation.

    Science.gov (United States)

    Mahato, S B; Garai, S

    1997-04-01

    Microbial biotransformations of various steroids are reviewed. Developmental studies on hydroxylation, carbon-carbon bond cleavage, enzymatic catalysis in nonaqueous solvents, use of cyclodextrin medium, cell immobilization, and new microbial reactions are highlighted. Various steroid substrates, their metabolites and the microorganisms used for the transformations are compiled covering the literature for the period 1992-1995.

  17. Waste to Watts and Water: Enabling Self-Contained Facilities Using Microbial Fuel Cells

    Science.gov (United States)

    2009-03-01

    biofuels and biomass, hydrogen 5 fuel cells, protein - or enzyme-based fuel cells, solar power, wind power, and desalination plants. A brief...Waste to Watts and Water Enabling Self-Contained Facilities Using Microbial Fuel Cells Amanda Sue Birch, P. E. Major, USAFR Air Command and...Water: Enabling Self-Contained Facilities Using Microbial Fuel Cells 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S

  18. Residual stress by repair welds

    International Nuclear Information System (INIS)

    Mochizuki, Masahito; Toyoda, Masao

    2003-01-01

    Residual stress by repair welds is computed using the thermal elastic-plastic analysis with phase-transformation effect. Coupling phenomena of temperature, microstructure, and stress-strain fields are simulated in the finite-element analysis. Weld bond of a plate butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. Microstructure is considered by using CCT diagram and the transformation behavior in the repair weld is also simulated. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress. (author)

  19. Hydrodynamics of microbial filter feeding

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

    2017-01-01

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate...... amounts of water. Also, the trade-off in the filter spacing remains unexplored, despite its simple formulation: A filter too coarse will allow suitably sized prey to pass unintercepted, whereas a filter too fine will cause strong flow resistance. We quantify the feeding flow of the filter......-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude...

  20. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    Science.gov (United States)

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  1. Effect of vegetation manipulation of abandoned arable land on soil microbial properties

    NARCIS (Netherlands)

    Maly, S.; Korthals, G.W.; Van Dijk, C.; Van der Putten, W.H.; De Boer, W.

    2000-01-01

    The effect of vegetation composition on various soil microbial properties in abandoned arable land was investigated 2 years after agricultural practice had terminated. Microbial numbers and processes were determined in five replicate plots of each of the following treatments: continued agricultural

  2. ASM News Volume 71 Number 9, 2005

    Energy Technology Data Exchange (ETDEWEB)

    Tamar Barkay and Barth F. Smets

    2005-01-01

    Genetic exchanges among prokaryotes, formerly considered only a marginal phenomenon, increasingly are being viewed as profoundly affecting evolution. Indeed, some researchers argue for utterly revamping our concept of microbial speciation and phylogeny by replacing the traditional ''tree'' with a newer ''net'' to account for these horizontal transfers of genes. This conceptual ferment is occurring while molecular biologists reveal how horizontal gene transfers occur even as microbes protect the integrity of their genomes. Other studies reveal the number and diversity and abundance of genetic elements that mediate horizontal gene transfers (HGTs) or facilitate genome rearrangements, deletions, and insertions. Taken together, this information suggests that microbial communities collectively possess a dynamic gene pool, where novel genetic combinations act as a driving force in genomic innovation, compensating individual microbial species for their inability to reproduce sexually. These microbial genomic dynamics can present both environmental threats and promise to humans. One major threat, for example, comes from the spread of antibiotic resistance and virulence genes among pathogenic microbes. Another less-documented issue involves transgenic plants and animals, whose uses are being restricted because of concerns that genes may be transferred to untargeted organisms where they might cause harm. A possible benefit from HGT comes from its potential to enhance the functional diversity of microbial communities and to improve their performance in changing or extreme environments. Such changes might be exploited, for example, as part of efforts to manage environmental pollution and might be achieved by spreading genes into resident microbes to confer specific biochemical activities.

  3. Influence of microbial symbionts on insect pheromones.

    Science.gov (United States)

    Engl, Tobias; Kaltenpoth, Martin

    2018-03-22

    Covering: up to 2018Pheromones serve as chemical signals between individuals of the same species and play important roles for mate localization and mate choice as well as other social interactions in insects. A growing body of literature indicates that microbial symbionts can modulate their hosts' chemical profiles, mate choice decisions and social behavior. This modulation can occur by the direct biosynthesis of pheromone components or the provisioning of precursors, or through general changes in the metabolite pool of the host and its resource allocation into pheromone production. Here we review and discuss the contexts in which microbial modulation of intraspecific communication in insects occurs and emphasize cases in which microbes are known to affect the involved chemistry. The described examples for a symbiotic influence on mate attraction and mate choice, aggregation, nestmate and kin recognition highlight the context-dependent costs and benefits of these symbiotic interactions and the potential for conflict and manipulation among the interacting partners. However, despite the increasing number of studies reporting on symbiont-mediated effects on insect chemical communication, experimentally validated connections between the presence of specific symbionts, changes in the host's chemistry, and behavioral effects thereof, remain limited to very few systems, highlighting the need for increased collaborative efforts between symbiosis researchers and chemical ecologists to gain more comprehensive insights into the influence of microbial symbionts on insect pheromones.

  4. Monitoring of microbial hydrocarbon remediation in the soil.

    Science.gov (United States)

    Chikere, Chioma Blaise; Okpokwasili, Gideon Chijioke; Chikere, Blaise Ositadinma

    2011-10-01

    Bioremediation of hydrocarbon pollutants is advantageous owing to the cost-effectiveness of the technology and the ubiquity of hydrocarbon-degrading microorganisms in the soil. Soil microbial diversity is affected by hydrocarbon perturbation, thus selective enrichment of hydrocarbon utilizers occurs. Hydrocarbons interact with the soil matrix and soil microorganisms determining the fate of the contaminants relative to their chemical nature and microbial degradative capabilities, respectively. Provided the polluted soil has requisite values for environmental factors that influence microbial activities and there are no inhibitors of microbial metabolism, there is a good chance that there will be a viable and active population of hydrocarbon-utilizing microorganisms in the soil. Microbial methods for monitoring bioremediation of hydrocarbons include chemical, biochemical and microbiological molecular indices that measure rates of microbial activities to show that in the end the target goal of pollutant reduction to a safe and permissible level has been achieved. Enumeration and characterization of hydrocarbon degraders, use of micro titer plate-based most probable number technique, community level physiological profiling, phospholipid fatty acid analysis, 16S rRNA- and other nucleic acid-based molecular fingerprinting techniques, metagenomics, microarray analysis, respirometry and gas chromatography are some of the methods employed in bio-monitoring of hydrocarbon remediation as presented in this review.

  5. Habitat constraints on the functional significance of soil microbial communities

    Science.gov (United States)

    Nunan, Naoise; Leloup, Julie; Ruamps, Léo; Pouteau, Valérie; Chenu, Claire

    2017-04-01

    An underlying assumption of most ecosystem models is that soil microbial communities are functionally equivalent; in other words, that microbial activity under given set of conditions is not dependent on the composition or diversity of the communities. Although a number of studies have suggested that this assumption is incorrect, ecosystem models can adequately describe ecosystem processes, such as soil C dynamics, without an explicit description of microbial functioning. Here, we provide a mechanistic basis for reconciling this apparent discrepancy. In a reciprocal transplant experiment, we show that microbial communities are not always functionally equivalent. The data suggest that when the supply of substrate is restricted, then the functioning of different microbial communities cannot be distinguished, but when the supply is less restricted, the intrinsic functional differences among communities can be expressed. When the supply of C is restricted then C dynamics are related to the properties of the physical and chemical environment of the soil. We conclude that soil C dynamics may depend on microbial community structure or diversity in environments such as the rhizosphere or the litter layer, but are less likely to do so in oligotrophic environments such as the mineral layers of soil.

  6. ONR Far East Scientific Bulletin, Volume 7, Number 2, April-June 1982,

    Science.gov (United States)

    1982-01-01

    atmospheric science, biomechanics, solid 22 state physics, microelectronics, bioconversion and solar energy; the National Technical University, Trondheim...Research Center (8) The major efforts of this center relate to bioconversion of waste cellulose materials into energy, chemicals, and microbial protein...The center’s objectives also include development of village level technology for utilization 23 of agricultural residues for biogas and other

  7. Halitosis: An oral microbial faction

    Directory of Open Access Journals (Sweden)

    Rajiv Saini

    2010-01-01

    Full Text Available Halitosis is a widespread condition and believed to affect one-quarter of the population around the world; also, most people have this condition from time to time. Breath malodour may be an important factor in social communication, and therefore may be the origin of concern not only for a possible health condition but also for frequent psychological alterations, leading to social and personal isolation. The most conspicuous malodorous compounds are termed volatile sulphur compounds (VSCs, with hydrogen sulphide, methyl mercaptan, and dimethyl sulphide accounting for roughly 90% of the VSCs. A number of oral bacteria, especially Gram-negative anaerobic species found in the subgingival plaque, produce a diverse array of malodorous compounds as byproducts of their metabolism, including VSCs and short-chain organic acids. Assessment and management of halitosis is of paramount importance in enhancing the overall health; moreover, dentists play a significant role in combating halitosis by reducing the oral microbial stack. Thus, the aim of the present review was to describe the aetiological factors, assessment tools, and therapeutic approaches related to halitosis.

  8. Microbial activity in soil cultivated with different summer legumes in coffee crop

    Directory of Open Access Journals (Sweden)

    Elcio Liborio Balota

    2011-02-01

    Full Text Available A field experiment was conducted for ten years in a sandy soil in the north part of the Paraná State, Brazil. The soil samples were collected at 0-10 cm depth, both under the coffee canopy and in the inter row space between the coffee plants, in the following treatments: Control, Leucaena leucocephala, Crotalaria spectabilis, Crotalaria breviflora, Mucuna pruriens, Mucuna deeringiana, Arachis hypogaea and Vigna unguiculata. The legume crops influenced the microbial activity, both under the coffee canopy and in the inter row space. The cultivation of Leucaena leucocephala increased the microbial biomass C, N and P. Although L. leucocephala and Arachis hypogaea provided higher microbial biomass, the qCO2 decreased by up to 50% under the coffee canopy and by about 25% in the inter row space. The soil microbial biomass was enriched in N and P due to green manure residue addition.

  9. Chebyshev's bias for composite numbers with restricted prime divisors

    NARCIS (Netherlands)

    Moree, Pieter

    2001-01-01

    Let P(x,d,a) denote the number of primes p<=x with p=a(mod d). Chebyshev's bias is the phenomenon that `more often' P(x;d,n)>P(x;d,r), than the other way around, where n is a quadratic non-residue mod d and r is a quadratic residue mod d. If P(x;d,n)>=P(x;d,r) for every x up to some large number,

  10. On the number of special numbers

    Indian Academy of Sciences (India)

    ... factorizaton for all exponents. Let V ( x ) be the number of special numbers ≤ x . We will prove that there is a constant c > 1 such that V ( x ) ∼ c x l o g x . We will make some remarks on determining the error term at the end. Using the explicit abc conjecture, we will study the existence of 23 consecutive special integers.

  11. Microbial amensalism in Lactobacillus casei and Pseudomonas taetrolens mixed culture.

    Science.gov (United States)

    García, Cristina; Rendueles, Manuel; Díaz, Mario

    2017-07-01

    Pseudomonas taetrolens has recently been revealed as an effective microbial producer of lactobionic acid from carbohydrates contained in dairy byproducts. In terms of food industrial applications, the implementation of lactobionic acid biosynthesis coupled with the classic bacterial production of lactic acid appears an important goal. This research paper studies the simultaneous fermentation of residual cheese whey by P. taetrolens and Lactobacillus casei to co-produce lactic and lactobionic acids. Experimental data showed the importance of the interactions established between the two microorganisms. Changes in physiology, viability, growth, and productive capacity were tested experimentally. Lactobacillus was not seen to suffer any appreciable stress, but considerable variations were observed in the Pseudomonas behavior presumably owing to inhibitory lactic metabolites, interaction that can be classified as microbial amensalism. As to production, lactic acid remained without significant changes in mixed fermentations, whereas the production of lactobionic acid decreased sharply due to the competitive exclusion of Pseudomonas.

  12. Nitrogen availability of biogas residues

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed Fouda, Sara

    2011-09-07

    The objectives of this study were to characterize biogas residues either unseparated or separated into a liquid and a solid phase from the fermentation of different substrates with respect to their N and C content. In addition, short and long term effects of the application of these biogas residues on the N availability and N utilization by ryegrass was investigated. It is concluded that unseparated or liquid separated biogas residues provide N at least corresponding to their ammonium content and that after the first fertilizer application the C{sub org}:N{sub org} ratio of the biogas residues was a crucial factor for the N availability. After long term application, the organic N accumulated in the soil leads to an increased release of N.

  13. Residual stress analysis: a review

    International Nuclear Information System (INIS)

    Finlayson, T.R.

    1983-01-01

    The techniques which are or could be employed to measure residual stresses are outlined. They include X-ray and neutron diffraction. Comments are made on the reliability and accuracy to be expected from particular techniques

  14. OECD Maximum Residue Limit Calculator

    Science.gov (United States)

    With the goal of harmonizing the calculation of maximum residue limits (MRLs) across the Organisation for Economic Cooperation and Development, the OECD has developed an MRL Calculator. View the calculator.

  15. Pacifiers: a microbial reservoir.

    Science.gov (United States)

    Comina, Elodie; Marion, Karine; Renaud, François N R; Dore, Jeanne; Bergeron, Emmanuelle; Freney, Jean

    2006-12-01

    The permanent contact between the nipple part of pacifiers and the oral microflora offers ideal conditions for the development of biofilms. This study assessed the microbial contamination on the surface of 25 used pacifier nipples provided by day-care centers. Nine were made of silicone and 16 were made of latex. The biofilm was quantified using direct staining and microscopic observations followed by scraping and microorganism counting. The presence of a biofilm was confirmed on 80% of the pacifier nipples studied. This biofilm was mature for 36% of them. Latex pacifier nipples were more contaminated than silicone ones. The two main genera isolated were Staphylococcus and Candida. Our results confirm that nipples can be seen as potential reservoirs of infections. However, pacifiers do have some advantages; in particular, the potential protection they afford against sudden infant death syndrome. Strict rules of hygiene and an efficient antibiofilm cleaning protocol should be established to answer the worries of parents concerning the safety of pacifiers.

  16. Drinking water microbial myths.

    Science.gov (United States)

    Allen, Martin J; Edberg, Stephen C; Clancy, Jennifer L; Hrudey, Steve E

    2015-01-01

    Accounts of drinking water-borne disease outbreaks have always captured the interest of the public, elected and health officials, and the media. During the twentieth century, the drinking water community and public health organizations have endeavored to craft regulations and guidelines on treatment and management practices that reduce risks from drinking water, specifically human pathogens. During this period there also evolved misunderstandings as to potential health risk associated with microorganisms that may be present in drinking waters. These misunderstanding or "myths" have led to confusion among the many stakeholders. The purpose of this article is to provide a scientific- and clinically-based discussion of these "myths" and recommendations for better ensuring the microbial safety of drinking water and valid public health decisions.

  17. [Fibers as carriers of microbial particles].

    Science.gov (United States)

    Górny, Rafał L; Ławniczek-Wałczyk, Anna; Stobnicka, Agata; Gołofit-Szymczak, Małgorzata; Cyprowski, Marcin

    2015-01-01

    The aim of the study was to assess the ability of natural, synthetic and semi-synthetic fibers to transport microbial particles. The simultaneously settled dust and aerosol sampling was carried out in 3 industrial facilities processing natural (cotton, silk, flax, hemp), synthetic (polyamide, polyester, polyacrylonitrile, polypropylene) and semi-synthetic (viscose) fibrous materials; 2 stables where horses and sheep were bred; 4 homes where dogs or cats were kept and 1 zoo lion pavilion. All samples were laboratory analyzed for their microbiological purity. The isolated strains were qualitatively identified. To identify the structure and arrangement of fibers that may support transport of microbial particles, a scanning electron microscopy analysis was performed. Both settled and airborne fibers transported analogous microorganisms. All synthetic, semi-synthetic and silk fibers, present as separated threads with smooth surface, were free from microbial contamination. Natural fibers with loose packing and rough surface (e.g., wool, horse hair), sheaf packing and septated surface (e.g., flax, hemp) or present as twisted ribbons with corrugated surface (cotton) were able to carry up to 9×10(5) cfu/g aerobic bacteria, 3.4×10(4) cfu/g anaerobic bacteria and 6.3×10(4) cfu/g of fungi, including pathogenic strains classified by Directive 2000/54/EC in hazard group 2. As plant and animal fibers are contaminated with a significant number of microorganisms, including pathogens, all of them should be mechanically eliminated from the environment. In factories, if the manufacturing process allows, they should be replaced by synthetic or semi-synthetic fibers. To avoid unwanted exposure to harmful microbial agents on fibers, the containment measures that efficiently limit their presence and dissemination in both occupational and non-occupational environments should be introduced. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  18. Influx of CO/sub 2/ from soil incubated organic residues at constant temperature

    International Nuclear Information System (INIS)

    Abro, S.A.

    2016-01-01

    Temperature induced CO/sub 2/ from genotupic residue substances is still less understood. Two types of organic residues (wheat-maize) were incubated at a constant temperature (25 degree C) to determine the rate and cumulative influx of CO/sub 2/ in laboratory experiment for 40 days. Further, the effect of surface and incorporated crop residues with and without phosphorus addition was also studied. Result revealed that mixing of crop residues increased CO/sub 2/-C evolution significantly and emission rare was 37% higher than that of control. At constant temperature, soil mixed residues, had higher emission rate CO/sub 2/-C than the residue superimposed. There was linear correlation of CO/sub 2/-C influxed for phosphorus levels and residue application ways with entire incubation at constant temperature. The mixing of organic residues to soil enhanced soil organic carbon levels and biomass of microbially bound N; however to little degree ammonium (NH/sub 4/-N) and nitrate NO/sub 3/-N nitrogen were decreased. (author)

  19. Detection of Gunshot Residues Using Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Regina Verena Taudte

    2014-01-01

    Full Text Available In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR- like particles in environmental and occupational samples. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS coupled to a chromatographic system is a powerful tool due to its high selectivity and sensitivity. Further, modern MS instruments can detect and identify a number of explosives and additives which may require different ionization techniques. Finally, MS has been applied to the analysis of both OGSR and inorganic gunshot residue (IGSR, although the “gold standard” for analysis is scanning electron microscopy with energy dispersive X-ray microscopy (SEM-EDX. This review presents an overview of the technical attributes of currently available MS and ionization techniques and their reported applications to GSR analysis.

  20. Identifying Functional Cysteine Residues in the Mitochondria.

    Science.gov (United States)

    Bak, Daniel W; Pizzagalli, Mattia D; Weerapana, Eranthie

    2017-04-21

    The mitochondria are dynamic organelles that regulate oxidative metabolism and mediate cellular redox homeostasis. Proteins within the mitochondria are exposed to large fluxes in the surrounding redox environment. In particular, cysteine residues within mitochondrial proteins sense and respond to these redox changes through oxidative modifications of the cysteine thiol group. These oxidative modifications result in a loss in cysteine reactivity, which can be monitored using cysteine-reactive chemical probes and quantitative mass spectrometry (MS). Analysis of cell lysates treated with cysteine-reactive probes enable the identification of hundreds of cysteine residues, however, the mitochondrial proteome is poorly represented (proteins and suppression of mitochondrial peptide MS signals by highly abundant cytosolic peptides. Here, we apply a mitochondrial isolation and purification protocol to substantially increase coverage of the mitochondrial cysteine proteome. Over 1500 cysteine residues from ∼450 mitochondrial proteins were identified, thereby enabling interrogation of an unprecedented number of mitochondrial cysteines. Specifically, these mitochondrial cysteines were ranked by reactivity to identify hyper-reactive cysteines with potential catalytic and regulatory functional roles. Furthermore, analyses of mitochondria exposed to nitrosative stress revealed previously uncharacterized sites of protein S-nitrosation on mitochondrial proteins. Together, the mitochondrial cysteine enrichment strategy presented herein enables detailed characterization of protein modifications that occur within the mitochondria during (patho)physiological fluxes in the redox environment.

  1. Residual extrapolation operators for efficient wavefield construction

    KAUST Repository

    Alkhalifah, Tariq Ali

    2013-02-27

    Solving the wave equation using finite-difference approximations allows for fast extrapolation of the wavefield for modelling, imaging and inversion in complex media. It, however, suffers from dispersion and stability-related limitations that might hamper its efficient or proper application to high frequencies. Spectral-based time extrapolation methods tend to mitigate these problems, but at an additional cost to the extrapolation. I investigate the prospective of using a residual formulation of the spectral approach, along with utilizing Shanks transform-based expansions, that adheres to the residual requirements, to improve accuracy and reduce the cost. Utilizing the fact that spectral methods excel (time steps are allowed to be large) in homogeneous and smooth media, the residual implementation based on velocity perturbation optimizes the use of this feature. Most of the other implementations based on the spectral approach are focussed on reducing cost by reducing the number of inverse Fourier transforms required in every step of the spectral-based implementation. The approach here fixes that by improving the accuracy of each, potentially longer, time step.

  2. Effects of Adopting Different Kinds of Collecting Method for Years on Film Residual Coefficient and Maize Yields

    Directory of Open Access Journals (Sweden)

    TANG Wen-xue

    2017-03-01

    Full Text Available Wide usage of mulching technology has increased crop yields, but the large amounts of mulching film residue resulting from widespread use of plastic film in China has brought about a series of pollution hazards. Based on a 4-year (2011-2014 long-term experiment, the effects of different kinds of collecting mothod (zero plastic film residues, conventional plastic film residues, whole plastic film residues remainded on plastic film residues, residual coefficient and maize yield were explored. Plastic film residues mainly remained in 0~10 cm, 10~20 cm soil layers. In 0~30 cm soil layers, the two types of mulch residues (>25 cm2, 4~25 cm2 under zero plastic film residues treatment were much less than conventional plastic film residues and whole plastic film residues remainded treatments, no significant differences were observed in the mulch residues (2 among 3 treatments. After maize harvest, the amount of plastic film residues under zero plastic film residues, conventional plastic film residues and whole plastic film residues remainded treatments were 52.71, 80.85 kg·hm-2 and 152.65 kg·hm-2, respectively, the residual coefficient for zero plastic film residues, conventional plastic film residues and whole plastic film residues remainded treatments were -9.45%, 8.53% and 54.42%, respectively. The stem diameter, ear length, ear width, ear row number, grain number per row and 100-grain weight of maize decreased with the increase of residual film amount. Compared with the conventional plastic film residues, the mean grain yield of whole plastic film residues remainded treatment decreased by 15.08%, whereas the zero plastic film residues treatment increased by 4.70%. The plastic film residues, residual coefficient and maize yield were comprehensively analyzed, the conventional plastic film residues practice should be adopted currently without appropriate plastic film residues collector. But from the long-term development, we should speed up the

  3. Vesícula residual

    Directory of Open Access Journals (Sweden)

    Júlio C. U. Coelho

    Full Text Available Our objective is to report three patients with recurrent severe upper abdominal pain secondary to residual gallbladder. All patients had been subjected to cholecystectomy from 1 to 20 years before. The diagnosis was established after several episodes of severe upper abdominal pain by imaging exams: ultrasonography, tomography, or endoscopic retrograde cholangiography. Removal of the residual gallbladder led to complete resolution of symptoms. Partial removal of the gallbladder is a very rare cause of postcholecystectomy symptoms.

  4. Ectomycorrhizal community structure and function in relation to forest residue harvesting and wood ash applications

    International Nuclear Information System (INIS)

    Mahmood, Shahid

    2000-05-01

    Ectomycorrhizal fungi form symbiotic associations with tree roots and assist in nutrient-uptake and -cycling in forest ecosystems, thereby constituting a most significant part of the microbial community. The aims of the studies described in this thesis were to evaluate the potential of DNA-based molecular methods in below-ground ectomycorrhizal community studies and to investigate changes in ectomycorrhizal communities on spruce roots in sites with different N deposition, and in sites subjected to harvesting of forest residues or application of wood ash. The ability of selected ectomycorrhizal fungi to mobilise nutrients from wood ash and to colonise root systems in the presence and absence of ash was also studied. In total 39 ectomycorrhizal species were detected in the experimental forests located in southern Sweden. At each site five to six species colonised around 60% of the root tips. The dominant species, common to the sites, were Tylospora fibrillosa, Thelephora terrestris and Cenococcum geophilum. Differences between two sites with differing levels of N deposition suggested that community structure may be influenced by N deposition, although site history, location and degree of isolation may also influence species composition. Repeated harvesting of forest residues reduced numbers of mycorrhizal roots in the humus layer to approximately 50% of that in control plots but no shift in the ectomycorrhizal community could be detected. At another site, application of granulated wood ash induced a shift in ectomycorrhizal community structure and three ectomycorrhizal fungi ('ash fungi') were found to colonise ash granules. Two 'ash fungi' showed a superior ability to solubilise stabilised wood ash in laboratory experiments compared to other ectomycorrhizal isolates from the same site. In laboratory microcosms containing intact mycorrhizal mycelia, colonisation of wood ash patches by one 'ash fungus' was good whereas colonisation by Piloderma croceum was poor. In a

  5. Marine Tar Residues: a Review.

    Science.gov (United States)

    Warnock, April M; Hagen, Scott C; Passeri, Davina L

    Marine tar residues originate from natural and anthropogenic oil releases into the ocean environment and are formed after liquid petroleum is transformed by weathering, sedimentation, and other processes. Tar balls, tar mats, and tar patties are common examples of marine tar residues and can range in size from millimeters in diameter (tar balls) to several meters in length and width (tar mats). These residues can remain in the ocean environment indefinitely, decomposing or becoming buried in the sea floor. However, in many cases, they are transported ashore via currents and waves where they pose a concern to coastal recreation activities, the seafood industry and may have negative effects on wildlife. This review summarizes the current state of knowledge on marine tar residue formation, transport, degradation, and distribution. Methods of detection and removal of marine tar residues and their possible ecological effects are discussed, in addition to topics of marine tar research that warrant further investigation. Emphasis is placed on benthic tar residues, with a focus on the remnants of the Deepwater Horizon oil spill in particular, which are still affecting the northern Gulf of Mexico shores years after the leaking submarine well was capped.

  6. Distribution of pesticide residues in soil and uncertainty of sampling.

    Science.gov (United States)

    Suszter, Gabriela K; Ambrus, Árpád

    2017-08-03

    Pesticide residues were determined in about 120 soil cores taken randomly from the top 15 cm layer of two sunflower fields about 30 days after preemergence herbicide treatments. Samples were extracted with acetone-ethyl acetate mixture and the residues were determined with GC-TSD. Residues of dimethenamid, pendimethalin, and prometryn ranged from 0.005 to 2.97 mg/kg. Their relative standard deviations (CV) were between 0.66 and 1.13. The relative frequency distributions of residues in soil cores were very similar to those observed in root and tuber vegetables grown in pesticide treated soils. Based on all available information, a typical CV of 1.00 was estimated for pesticide residues in primary soil samples (soil cores). The corresponding expectable relative uncertainty of sampling is 20% when composite samples of size 25 are taken. To obtain a reliable estimate of the average residues in the top 15 cm layer of soil of a field up to 8 independent replicate random samples should be taken. To obtain better estimate of the actual residue level of the sampled filed would be marginal if larger number of samples were taken.

  7. Manual of Standard Operating Procedures for Veterinary Drug Residue Analysis

    International Nuclear Information System (INIS)

    2016-01-01

    Laboratories are crucial to national veterinary drug residue monitoring programmes. However, one of the main challenges laboratories encounter is obtaining access to relevant methods of analysis. Thus, in addition to training, providing technical advice and transferring technology, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has resolved to develop clear and practical manuals to support Member State laboratories. The Coordinated Research Project (CRP) on Development of Radiometric and Allied Analytical Methods to Strengthen Residue Control Programs for Antibiotic and Anthelmintic Veterinary Drug Residues has developed a number of analytical methods as standard operating procedures (SOPs), which are now compiled here. This publication contains SOPs on chromatographic and spectrometric techniques, as well as radioimmunoassay and associated screening techniques, for various anthelmintic and antimicrobial veterinary drug residue analysis. Some analytical method validation protocols are also included. The publication is primarily aimed at food and environmental safety laboratories involved in testing veterinary drug residues, including under organized national residue monitoring programmes. It is expected to enhance laboratory capacity building and competence through the use of radiometric and complementary tools and techniques. The publication is also relevant for applied research on residues of veterinary drugs in food and environmental samples

  8. Soil C and N availability determine the priming effect: microbial N mining and stoichiometric decomposition theories

    Science.gov (United States)

    Chen, Ruirui; Senbayram, Mehmet; Blagodatsky, Sergey; Dittert, Klaus; Lin, Xiangui; Blagodatskaya, Evgenia; Kuzyakov, Yakov

    2014-05-01

    The increasing input of anthropogenically derived nitrogen (N) to ecosystems raises a crucial question: how does available N modify the decomposer community and thus affects the mineralization of soil organic matter (SOM). Moreover, N input modifies the priming effect (PE), that is, the effect of fresh organics on the microbial decomposition of SOM. We studied the interactive effects of C and N on SOM mineralization (by natural 13C labelling adding C4-sucrose or C4-maize straw to C3-soil) in relation to microbial growth kinetics and to the activities of five hydrolytic enzymes. This encompasses the groups of parameters governing two mechanisms of priming effects - microbial N mining and stoichiometric decomposition theories. In sole C treatments, positive PE was accompanied by a decrease in specific microbial growth rates, confirming a greater contribution of K-strategists to the decomposition of native SOM. Sucrose addition with N significantly accelerated mineralization of native SOM, whereas mineral N added with plant residues accelerated decomposition of plant residues. This supports the microbial mining theory in terms of N limitation. Sucrose addition with N was accompanied by accelerated microbial growth, increased activities of β-glucosidase and cellobiohydrolase, and decreased activities of xylanase and leucine amino peptidase. This indicated an increased contribution of r-strategists to the PE and to decomposition of cellulose but the decreased hemicellulolytic and proteolytic activities. Thus, the acceleration of the C cycle was primed by exogenous organic C and was controlled by N. This confirms the stoichiometric decomposition theory. Both K- and r-strategists were beneficial for priming effects, with an increasing contribution of K-selected species under N limitation. Thus, the priming phenomenon described in 'microbial N mining' theory can be ascribed to K-strategists. In contrast, 'stoichiometric decomposition' theory, that is, accelerated OM

  9. Exoelectrogenic bacteria that power microbial fuel cells

    KAUST Repository

    Logan, Bruce E.

    2009-03-30

    There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells. Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities. Enriched anodic biofilms have generated power densities as high as 6.9 W per m2 (projected anode area), and therefore are approaching theoretical limits. To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell-cell communication.

  10. Microbial biosensors for environmental monitoring

    Directory of Open Access Journals (Sweden)

    David VOGRINC

    2015-12-01

    Full Text Available Microbial biosensors are analytical devices capable of sensing substances in the environment due to the specific biological reaction of the microorganism or its parts. Construction of a microbial biosensor requires knowledge of microbial response to the specific analyte. Linking this response with the quantitative data, using a transducer, is the crucial step in the construction of a biosensor. Regarding the transducer type, biosensors are divided into electrochemical, optical biosensors and microbial fuel cells. The use of the proper configuration depends on the selection of the biosensing element. With the use of transgenic E. coli strains, bioluminescence or fluorescence based biosensors were developed. Microbial fuel cells enable the use of the heterogeneous microbial populations, isolated from wastewater. Different microorganisms are used for different pollutants – pesticides, heavy metals, phenolic compounds, organic waste, etc. Biosensing enables measurement of their concentration and their toxic or genotoxic effects on the microbes. Increasing environmental awareness has contributed to the increase of interest for biomonitoring. Although technologies, such as bioinformatics and genetic engineering, allow us to design complex and efficient microbial biosensors for environmental pollutants, the transfer of the laboratory work to the field still remains a problem to solve.

  11. The maturing of microbial ecology.

    Science.gov (United States)

    Schmidt, Thomas M

    2006-09-01

    A.J. Kluyver and C.B. van Niel introduced many scientists to the exceptional metabolic capacity of microbes and their remarkable ability to adapt to changing environments in The Microbe's Contribution to Biology. Beyond providing an overview of the physiology and adaptability of microbes, the book outlined many of the basic principles for the emerging discipline of microbial ecology. While the study of pure cultures was highlighted, provided a unifying framework for understanding the vast metabolic potential of microbes and their roles in the global cycling of elements, extrapolation from pure cultures to natural environments has often been overshadowed by microbiologists inability to culture many of the microbes seen in natural environments. A combination of genomic approaches is now providing a culture-independent view of the microbial world, revealing a more diverse and dynamic community of microbes than originally anticipated. As methods for determining the diversity of microbial communities become increasingly accessible, a major challenge to microbial ecologists is to link the structure of natural microbial communities with their functions. This article presents several examples from studies of aquatic and terrestrial microbial communities in which culture and culture-independent methods are providing an enhanced appreciation for the microbe's contribution to the evolution and maintenance of life on Earth, and offers some thoughts about the graduate-level educational programs needed to enhance the maturing field of microbial ecology.

  12. Humic substances-mediated microbial reductive dehalogenation of triclosan

    Science.gov (United States)

    Wang, L.; Xu, S.; Yang, Y.

    2015-12-01

    The role of natural organic matter in regulating the redox reactions as an electron shuttle has received lots of attention, because it can significantly affect the environmental degradation of contaminants and biogeochemical cycles of major elements. However, up to date, limited studies examined the role of natural organic matter in affecting the microbial dehalogenation of emergent organohalides, a critical detoxification process. In this study, we investigated the humic substance (HS)-mediated microbial dehalogenation of triclosan, a widely used antimicrobial agent. We found that the presence of HS stimulated the microbial degradation of triclosan by Shewanella putrefaciens CN-32. In the absence of HS, the triclosan was degraded gradually, achieving 8.6% residual at 8 days. With HS, the residual triclosan was below 2% after 4 days. Cl- was confirmed by ion chromatography analysis, but the dehalogenation processes and other byproducts warrant further investigations. The impact of HS on the degradation of triclosan was highly dependent on the concentration of HS. When the HS was below 15 mg/L, the degradation rate constant for triclosan increased with the organic carbon concentration. Beyond that point, the increased organic carbon concentration decreased the degradation of triclosan. Microbially pre-reduced HS abiotically reduced triclosan, testifying the electron shuttling processes. These results indicate that dissolved organic matter plays a dual role in regulating the degradation of triclosan: it mediates electron transport and inhibits the bioavailability through complexation. Such novel organic matter-mediated reactions for organohalides are important for evaluating the natural attenuation of emergent contaminants and designing cost-effective engineering treatment.

  13. Number words and number symbols a cultural history of numbers

    CERN Document Server

    Menninger, Karl

    1992-01-01

    Classic study discusses number sequence and language and explores written numerals and computations in many cultures. "The historian of mathematics will find much to interest him here both in the contents and viewpoint, while the casual reader is likely to be intrigued by the author's superior narrative ability.

  14. Volume 9 Number 3

    African Journals Online (AJOL)

    OLUWOLE

    soybean residue management and starter nitrogen (N0K0) led to negative nutrient balance (-27 Kg N ha-1). Key words; partial nutrient balance, intercrop, ... The objectives of this research therefore, were to select soybean variety most ..... sustainability in Sub-saharan African. Agriculture. Special issue Ag. Ecosys. Env., 7.

  15. Sector in numbers

    International Nuclear Information System (INIS)

    Ministerio de Energia y Minas

    2003-01-01

    This is an article that shows statistical data on imports, exports and fuel consumption in Guatemala of crude petroleum, gas oils, petroleum residues and prices for exportation of petroleum and sale prices of gasoline and diesel covering the period 2002-July 2003

  16. Sector in numbers

    International Nuclear Information System (INIS)

    Ministerio de Energia y Minas

    2002-01-01

    This is an article that shows statistical data on imports, exports and fuel consumption in Guatemala of crude petroleum, gas oils, petroleum residues and prices for exportation of petroleum and sale prices of gasoline and diesel covering years since 1995. This includes statistics updated until march 2002

  17. Sector in numbers

    International Nuclear Information System (INIS)

    Ministerio de Energia y Minas

    2003-01-01

    This is an article that shows statistical data on imports, exports and fuel consumption in Guatemala of crude petroleum, gas oils, petroleum residues and prices for exportation of petroleum and sale prices of gasoline and diesel covering the period 2002-October 2003

  18. Actinorhizal Alder Phytostabilization Alters Microbial Community Dynamics in Gold Mine Waste Rock from Northern Quebec: A Greenhouse Study.

    Directory of Open Access Journals (Sweden)

    Katrina L Callender

    Full Text Available Phytotechnologies are rapidly replacing conventional ex-situ remediation techniques as they have the added benefit of restoring aesthetic value, important in the reclamation of mine sites. Alders are pioneer species that can tolerate and proliferate in nutrient-poor, contaminated environments, largely due to symbiotic root associations with the N2-fixing bacteria, Frankia and ectomycorrhizal (ECM fungi. In this study, we investigated the growth of two Frankia-inoculated (actinorhizal alder species, A. crispa and A. glutinosa, in gold mine waste rock from northern Quebec. Alder species had similar survival rates and positively impacted soil quality and physico-chemical properties in similar ways, restoring soil pH to neutrality and reducing extractable metals up to two-fold, while not hyperaccumulating them into above-ground plant biomass. A. glutinosa outperformed A. crispa in terms of growth, as estimated by the seedling volume index (SVI, and root length. Pyrosequencing of the bacterial 16S rRNA gene for bacteria and the ribosomal internal transcribed spacer (ITS region for fungi provided a comprehensive, direct characterization of microbial communities in gold mine waste rock and fine tailings. Plant- and treatment-specific shifts in soil microbial community compositions were observed in planted mine residues. Shannon diversity and the abundance of microbes involved in key ecosystem processes such as contaminant degradation (Sphingomonas, Sphingobium and Pseudomonas, metal sequestration (Brevundimonas and Caulobacter and N2-fixation (Azotobacter, Mesorhizobium, Rhizobium and Pseudomonas increased over time, i.e., as plants established in mine waste rock. Acetate mineralization and most probable number (MPN assays showed that revegetation positively stimulated both bulk and rhizosphere communities, increasing microbial density (biomass increase of 2 orders of magnitude and mineralization (five-fold. Genomic techniques proved useful in

  19. Mild salinization stimulated glyphosate degradation and microbial activities in a riparian soil from Chongming Island, China.

    Science.gov (United States)

    Yang, Changming; Shen, Shuo; Wang, Mengmeng; Li, Jianhua

    2013-04-01

    An incubation experiment was conducted to investigate the effects of simulated saltwater treatment with different percentages of artificial seawater on degradation dynamics of herbicide glyphosate and microbial activities in a riparian soil in Chongming Island, China. The results showed that 10% seawater treatment showed significantly enhancing effects on degradation efficiency of glyphosate with the lowest residual concentration among all the treatments. However, glyphosate degradation was markedly decreased in the riparian soil with 20% and 50% seawater treatments. The half-lives for 20% and 50% seawater treatments were prolonged by 12.1 and 39.0%, respectively, as compared to control. Microbial investigation indicated that 10% seawater treatment significantly stimulated microbial activities in the glyphosate-spiked riparian soil throughout the incubation period. At 42 day of incubation experiment, flourescein diacetate (FDA) hydrolysis rate, microbial adenosine triphosphate (ATP), and basal soil respiration (BSR) in the glyphosate-spiked riparian soil with 10% seawater were 59.2, 42.5 and 31.8% higher than those with no saltwater treatment, respectively. In contrast, saltwater treatment with 50% seawater significantly inhibited microbial activities. Especially, FDA hydrolysis rate, microbial ATP and BSR were decreased by 66.4, 58.6 and 66.8%, respectively, as compared to control. The results indicate that levels of simulated saltwater can exert variable effects on herbicide degradation dynamics and microbial parameters in the riparian soil.

  20. Soil aggregation and associated microbial communities modify the impact of agricultural management on carbon content.

    Science.gov (United States)

    Trivedi, Pankaj; Delgado-Baquerizo, Manuel; Jeffries, Thomas C; Trivedi, Chanda; Anderson, Ian C; Lai, Kaitao; McNee, Matthew; Flower, Kenneth; Pal Singh, Bhupinder; Minkey, David; Singh, Brajesh K

    2017-08-01

    Soil carbon (C) stabilisation is known to depend in part on its distribution in structural aggregates, and upon soil microbial activity within the aggregates. However, the mechanisms and relative contributions of different microbial groups to C turnover in different aggregates under various management practices remain unclear. The aim of this study was to determine the role of soil aggregation and their associated microbial communities in driving the responses of soil organic matter (SOM) to multiple management practices. Our results demonstrate that higher amounts of C inputs coupled with greater soil aggregation in residue retention management practices has positive effects on soil C content. Our results provide evidence that different aggregate size classes support distinct microbial habitats which supports the colonisation of different microbial communities. Most importantly our results indicate that the effects of management practices on soil C is modulated by soil aggregate sizes and their associated microbial community and are more pronounced in macro-aggregate compared with micro-aggregate sizes. Based on our findings we recommend that differential response of management practices and microbial control on the C turnover in macro-aggregates and micro-aggregate should be explicitly considered when accounting for management impacts on soil C turnover. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. The microbial ecology of permafrost

    DEFF Research Database (Denmark)

    Jansson, Janet; Tas, Neslihan

    2014-01-01

    Permafrost constitutes a major portion of the terrestrial cryosphere of the Earth and is a unique ecological niche for cold-adapted microorganisms. There is a relatively high microbial diversity in permafrost, although there is some variation in community composition across different permafrost......-gas emissions. This Review describes new data on the microbial ecology of permafrost and provides a platform for understanding microbial life strategies in frozen soil as well as the impact of climate change on permafrost microorganisms and their functional roles....

  2. Evaluation of residue-residue contact prediction in CASP10

    KAUST Repository

    Monastyrskyy, Bohdan

    2013-08-31

    We present the results of the assessment of the intramolecular residue-residue contact predictions from 26 prediction groups participating in the 10th round of the CASP experiment. The most recently developed direct coupling analysis methods did not take part in the experiment likely because they require a very deep sequence alignment not available for any of the 114 CASP10 targets. The performance of contact prediction methods was evaluated with the measures used in previous CASPs (i.e., prediction accuracy and the difference between the distribution of the predicted contacts and that of all pairs of residues in the target protein), as well as new measures, such as the Matthews correlation coefficient, the area under the precision-recall curve and the ranks of the first correctly and incorrectly predicted contact. We also evaluated the ability to detect interdomain contacts and tested whether the difficulty of predicting contacts depends upon the protein length and the depth of the family sequence alignment. The analyses were carried out on the target domains for which structural homologs did not exist or were difficult to identify. The evaluation was performed for all types of contacts (short, medium, and long-range), with emphasis placed on long-range contacts, i.e. those involving residues separated by at least 24 residues along the sequence. The assessment suggests that the best CASP10 contact prediction methods perform at approximately the same level, and comparably to those participating in CASP9.

  3. Contribution of microorganisms to non-extractable residue formation during biodegradation of ibuprofen in soil

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Karolina M., E-mail: karolina.nowak@ufz.de [UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Department of Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Girardi, Cristobal; Miltner, Anja [UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Gehre, Matthias [UFZ, Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstraße 15, 04318 Leipzig (Germany); Schäffer, Andreas [Department of Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Kästner, Matthias [UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany)

    2013-02-15

    Non-extractable residues (NER) formed during biodegradation of organic contaminants in soil are considered to be mainly composed of parent compounds or their primary metabolites with hazardous potential. However, in the case of biodegradable organic compounds, the soil NER may also contain microbial biomass components, for example fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are subsequently incorporated into non-living soil organic matter (SOM) and are stabilised ultimately forming hardly extractable residues of biogenic origin. We investigated biodegradation of {sup 13}C{sub 6}-ibuprofen, in particular the metabolic incorporation of the {sup 13}C-label into FA and AA and their fate in soil over 90 days. {sup 13}C-FA and {sup 13}C-AA amounts in the living microbial biomass fraction initially increased, then decreased over time and were continuously incorporated into the non-living SOM pool. The {sup 13}C-FA in the non-living SOM remained stable from day 59 whereas the contents of {sup 13}C-AA slightly increased until the end. After 90 days, nearly all NER were biogenic as they were made up almost completely by natural biomass compounds. The presented data demonstrated that the potential environmental risks related to the ibuprofen-derived NER are overestimated. - Highlights: ► Biogenic residue formation during microbial degradation of ibuprofen was studied. ► Nearly all non-extractable residues derived from ibuprofen were biogenic. ► Fatty acids and amino acids formed biogenic non-extractable residues and were stabilised in soil. ► Environmental risks of ibuprofen-derived non-extractable residues are overestimated.

  4. Contribution of microorganisms to non-extractable residue formation during biodegradation of ibuprofen in soil

    International Nuclear Information System (INIS)

    Nowak, Karolina M.; Girardi, Cristobal; Miltner, Anja; Gehre, Matthias; Schäffer, Andreas; Kästner, Matthias

    2013-01-01

    Non-extractable residues (NER) formed during biodegradation of organic contaminants in soil are considered to be mainly composed of parent compounds or their primary metabolites with hazardous potential. However, in the case of biodegradable organic compounds, the soil NER may also contain microbial biomass components, for example fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are subsequently incorporated into non-living soil organic matter (SOM) and are stabilised ultimately forming hardly extractable residues of biogenic origin. We investigated biodegradation of 13 C 6 -ibuprofen, in particular the metabolic incorporation of the 13 C-label into FA and AA and their fate in soil over 90 days. 13 C-FA and 13 C-AA amounts in the living microbial biomass fraction initially increased, then decreased over time and were continuously incorporated into the non-living SOM pool. The 13 C-FA in the non-living SOM remained stable from day 59 whereas the contents of 13 C-AA slightly increased until the end. After 90 days, nearly all NER were biogenic as they were made up almost completely by natural biomass compounds. The presented data demonstrated that the potential environmental risks related to the ibuprofen-derived NER are overestimated. - Highlights: ► Biogenic residue formation during microbial degradation of ibuprofen was studied. ► Nearly all non-extractable residues derived from ibuprofen were biogenic. ► Fatty acids and amino acids formed biogenic non-extractable residues and were stabilised in soil. ► Environmental risks of ibuprofen-derived non-extractable residues are overestimated

  5. Microarray-based analysis of survival of soil microbial community during ozonation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian; Van Nostrand, Joy D.; He, Zhili; Wu, Liyou; Deng, Ye; Zhang, Xu; Zhou, Jizhong; Li, Guanghe

    2010-05-17

    A 15 h ozonation was performed on bioremediated soil to remove recalcitrant residual oil. To monitor the survival of indigenous microorganisms in the soil during in-situ chemical oxidation(ISCO) culturing and a functional genearray, GeoChip, was used to examine the functional genes and structure of the microbial community during ozonation (0h, 2h, 4h, 6h, 10hand15h). Breakthrough ozonation decreased the population of cultivable heterotrophic bacteria by about 3 orders of magnitude. The total functional gene abundance and diversity decreased during ozonation, as the number of functional genes was reduced by 48percent after 15 h. However, functional genes were evenly distributed during ozonation as judged by the Shannon-Weaver Evenness index. A sharp decrease in gene number was observed in the first 6 h of ozonation followed by a slower decrease in the next 9 h, which was consistent with microbial populations measured by a culture based method. Functional genes involved in carbon, nitrogen, phosphors and sulfur cycling, metal resistance and organic remediation were detected in all samples. Though the pattern of gene categories detected was similar for all time points, hierarchica lcluster of all functional genes and major functional categories all showed a time-serial pattern. Bacteria, archaea and fungi decreased by 96.1percent, 95.1percent and 91.3percent, respectively, after 15 h ozonation. Delta proteobacteria, which were reduced by 94.3percent, showed the highest resistance to ozonation while Actinobacteria, reduced by 96.3percent, showed the lowest resistance. Microorganisms similar to Rhodothermus, Obesumbacterium, Staphylothermus, Gluconobacter, and Enterococcus were dominant at all time points. Functional genes related to petroleum degradation decreased 1~;;2 orders of magnitude. Most of the key functional genes were still detected after ozonation, allowing a rapid recovery of the microbial community after ozonation. While ozone had a large impact on the

  6. Basal respiration and stratification ratio in soil cultivated with citrus and treated with organic residues in the state of Sergipe

    Directory of Open Access Journals (Sweden)

    Juliana Augusta Moura

    2015-04-01

    Full Text Available The use of organic residues in the soil to improve its quality, provide nutrients to plant growth and increase carbon storage is an ancient practice, but little is known about the application of laminar composting in citrus orchards. The objective of this study was to evaluate the microbial activity through microbial respiration, and the different rates stratification of some variables related to this attribute of an Ultisol cultivated with citrus and treated with organic waste in the state of Sergipe. Soil samples were collected in the layers 0-5 cm, 5-10 cm, and 10-15 cm in a citrus orchard (Citrus sinensis, L. Osbeck under different treatments 1. Layering organic residue (crop wastes placed in layers under the plant canopy 2. Layering organic residue + NPK (the same as described in iten 1 + NPK; 3. Humus (Humified organic compost applied under the plant canopy; 4. Humus + NPK (the same as described in iten 3 + NPK; 5. Control + NPK (plant canopy was kept free of residues, + NPK application; 6. Control – NPK (plant canopy was kept free of residues, without application of NPK, with three replications. It has been found that the use of the organic residue in the plant canopy increased microbial respiration rate and total organic matter content, as well as an increase in some chemical attributes as pH, P, Ca and Mg in all treatments compared the control. The ratio stratification was effective to evaluate the influence of different management practices between depths demonstrating an improvement in microbial activity by more practical conservation treatments and indicating that the use of Humus, humus + NPK and alternate layering residues + NPK were the most effective in increasing the organic matter content in the soil

  7. Evaluation of physico-chemical and microbial parameters on water ...

    African Journals Online (AJOL)

    Microsoft Windows

    microbial analysis was also conducted in terms of most probable number (MPN) of total coliforms in water sample and its highest value ... meter for the sanitary analysis of water. The test is used to detect coliforms, a ..... Brown RM, Mc Cleiland NJ, Deininger RA, O'Connor MF (1972). A. Water Quality Index-crossing the ...

  8. Microbial analysis in biogas reactors suffering by foaming incidents

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; De Francisci, Davide; Treu, Laura

    2014-01-01

    , lipids and carbohydrates before and after foaming incidents was characterized using 16S rRNA gene sequencing. Moreover, the microbial diversity between the liquid and foaming layer was assessed. A number of genera that are known to produce biosurfactants, contain mycolic acid in their cell wall...

  9. Biolog for the determination of diversity in microbial communities ...

    African Journals Online (AJOL)

    In this study, different carbon source profiles were generated by inoculating Biolog GN and GP microtitre plates, with different dilutions of microbial communities. The high number of substrates utilised at the lower dilutions (10-1 and 10-2) indicated a high functional diversity in the communities tested. This, however, did not ...

  10. Modeling Logistic Performance in Quantitative Microbial Risk Assessment

    NARCIS (Netherlands)

    Rijgersberg, H.; Tromp, S.O.; Jacxsens, L.; Uyttendaele, M.

    2010-01-01

    In quantitative microbial risk assessment (QMRA), food safety in the food chain is modeled and simulated. In general, prevalences, concentrations, and numbers of microorganisms in media are investigated in the different steps from farm to fork. The underlying rates and conditions (such as storage

  11. Those fascinating numbers

    CERN Document Server

    Koninck, Jean-Marie De

    2009-01-01

    Who would have thought that listing the positive integers along with their most remarkable properties could end up being such an engaging and stimulating adventure? The author uses this approach to explore elementary and advanced topics in classical number theory. A large variety of numbers are contemplated: Fermat numbers, Mersenne primes, powerful numbers, sublime numbers, Wieferich primes, insolite numbers, Sastry numbers, voracious numbers, to name only a few. The author also presents short proofs of miscellaneous results and constantly challenges the reader with a variety of old and new n

  12. Microbial Cell Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Doktycz, Mitchel John [ORNL; Sullivan, Claretta [Eastern Virginia Medical School; Mortensen, Ninell P [ORNL; Allison, David P [ORNL

    2011-01-01

    limitation on the maximum scan size (roughly 100 x 100 {mu}m) and the restricted movement of the cantilever in the Z (or height) direction. In most commercial AFMs, the Z range is restricted to roughly 10 {mu}m such that the height of cells to be imaged must be seriously considered. Nevertheless, AFM can provide structural-functional information at nanometer resolution and do so in physiologically relevant environments. Further, instrumentation for scanning probe microscopy continues to advance. Systems for high-speed imaging are becoming available, and techniques for looking inside the cells are being demonstrated. The ability to combine AFM with other imaging modalities is likely to have an even greater impact on microbiological studies. AFM studies of intact microbial cells started to appear in the literature in the 1990s. For example, AFM studies of Saccharomyces cerevisiae examined buddings cars after cell division and detailed changes related to cell growth processes. Also, the first AFM studies of bacterial biofilms appeared. In the late 1990s, AFM studies of intact fungal spores described clear changes in spore surfaces upon germination, and studies of individual bacterial cells were also described. These early bacterial imaging studies examined changes in bacterial morphology due to antimicrobial peptides exposure and bacterial adhesion properties. The majority of these early studies were carried out on dried samples and took advantage of the resolving power of AFM. The lack of cell mounting procedures presented an impediment for cell imaging studies. Subsequently, several approaches to mounting microbial cells have been developed, and these techniques are described later. Also highlighted are general considerations for microbial imaging and a description of some of the various applications of AFM to microbiology.

  13. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  14. Seasonality in ocean microbial communities.

    Science.gov (United States)

    Giovannoni, Stephen J; Vergin, Kevin L

    2012-02-10

    Ocean warming occurs every year in seasonal cycles that can help us to understand long-term responses of plankton to climate change. Rhythmic seasonal patterns of microbial community turnover are revealed when high-resolution measurements of microbial plankton diversity are applied to samples collected in lengthy time series. Seasonal cycles in microbial plankton are complex, but the expansion of fixed ocean stations monitoring long-term change and the development of automated instrumentation are providing the time-series data needed to understand how these cycles vary across broad geographical scales. By accumulating data and using predictive modeling, we gain insights into changes that will occur as the ocean surface continues to warm and as the extent and duration of ocean stratification increase. These developments will enable marine scientists to predict changes in geochemical cycles mediated by microbial communities and to gauge their broader impacts.

  15. When microbial conversations get physical.

    Science.gov (United States)

    Reguera, Gemma

    2011-03-01

    It is widely accepted that microorganisms are social beings. Whereas communication via chemical signals (e.g. quorum sensing) has been the focus of most investigations, the use of physical signals for microbial cell-cell communication has received only limited attention. In this Opinion article, I postulate that physical modes of microbial communication could be widespread in nature. This is based on experimental evidence on the microbial emission and response to three physical signals: sound waves, electromagnetic radiation and electric currents. These signals propagate rapidly, and even at very low intensities, they provide useful mechanisms when a rapid response is required. I also make some suggestions for promising future research avenues that could provide novel and unsuspected insights into the physical nature of microbial signaling networks. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. MICROBIAL MATS - A JOINT VENTURE

    NARCIS (Netherlands)

    VANGEMERDEN, H

    Microbial mats characteristically are dominated by a few functional groups of microbes: cyanobacteria, colorless sulfur bacteria, purple sulfur bacteria, and sulfate-reducing bacteria. Their combined metabolic activities result in steep environmental microgradients, particularly of oxygen and

  17. Towards efficient bioethanol production from agricultural and forestry residues: Exploration of unique natural microorganisms in combination with advanced strain engineering.

    Science.gov (United States)

    Zhao, Xinqing; Xiong, Liang; Zhang, Mingming; Bai, Fengwu

    2016-09-01

    Production of fuel ethanol from lignocellulosic feedstocks such as agricultural and forestry residues is receiving increasing attention due to the unsustainable supply of fossil fuels. Three key challenges include high cellulase production cost, toxicity of the cellulosic hydrolysate to microbial strains, and poor ability of fermenting microorganisms to utilize certain fermentable sugars in the hydrolysate. In this article, studies on searching of natural microbial strains for production of unique cellulase for biorefinery of agricultural and forestry wastes, as well as development of strains for improved cellulase production were reviewed. In addition, progress in the construction of yeast strains with improved stress tolerance and the capability to fully utilize xylose and glucose in the cellulosic hydrolysate was also summarized. With the superior microbial strains for high titer cellulase production and efficient utilization of all fermentable sugars in the hydrolysate, economic biofuels production from agricultural residues and forestry wastes can be realized. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Residual stresses around Vickers indents

    International Nuclear Information System (INIS)

    Pajares, A.; Guiberteau, F.; Steinbrech, R.W.

    1995-01-01

    The residual stresses generated by Vickers indentation in brittle materials and their changes due to annealing and surface removal were studied in 4 mol% yttria partially stabilized zirconia (4Y-PSZ). Three experimental methods to gain information about the residual stress field were applied: (i) crack profile measurements based on serial sectioning, (ii) controlled crack propagation in post indentation bending tests and (iii) double indentation tests with smaller secondary indents located around a larger primary impression. Three zones of different residual stress behavior are deduced from the experiments. Beneath the impression a crack free spherical zone of high hydrostatic stresses exists. This core zone is followed by a transition regime where indentation cracks develop but still experience hydrostatic stresses. Finally, in an outward third zone, the crack contour is entirely governed by the tensile residual stress intensity (elastically deformed region). Annealing and surface removal reduce this crack driving stress intensity. The specific changes of the residual stresses due to the post indentation treatments are described and discussed in detail for the three zones

  19. Marine sponges as microbial fermenters

    OpenAIRE

    Hentschel, Ute; Usher, Kayley M.; Taylor, Michael W.

    2006-01-01

    The discovery of phylogenetically complex, yet highly sponge-specific microbial communities in marine sponges, including novel lineages and even candidate phyla, came as a surprise. At the same time, unique research opportunities opened up, because the microorganisms of sponges are in many ways more accessible than those of seawater. Accordingly, we consider sponges as microbial fermenters that provide exciting new avenues in marine microbiology and biotechnology. This review covers recent fi...

  20. Microbial genomes: Blueprints for life

    Energy Technology Data Exchange (ETDEWEB)

    Relman, David A.; Strauss, Evelyn

    2000-12-31

    Complete microbial genome sequences hold the promise of profound new insights into microbial pathogenesis, evolution, diagnostics, and therapeutics. From these insights will come a new foundation for understanding the evolution of single-celled life, as well as the evolution of more complex life forms. This report is an in-depth analysis of scientific issues that provides recommendations and will be widely disseminated to the scientific community, federal agencies, industry and the public.

  1. Contaminant immobilization via microbial activity

    International Nuclear Information System (INIS)

    1991-11-01

    The aim of this study was to search the literature to identify biological techniques that could be applied to the restoration of contaminated groundwaters near uranium milling sites. Through bioremediation it was hypothesized that the hazardous heavy metals could be immobilized in a stable, low-solubility form, thereby halting their progress in the migrating groundwater. Three basic mechanisms were examined: reduction of heavy metals by microbially produced hydrogen sulfide; direct microbial mediated reduction; and biosorption

  2. USE OF ORGANIC RESIDUES FOR THE RECOVERY OF SOIL AND ENVIRONMENTAL SUSTAINABILITY

    Directory of Open Access Journals (Sweden)

    Antonia Galvez

    2011-12-01

    Full Text Available The aim of this work was to investigate the effects of different organic residues on soil fertility and climate change, through the evaluation of soil organic matter mineralisation, greenhouse gas emission, nutrient availability and soil microbial biomass content and activity. A degraded agricultural soil was amended with three different organic residues (pig slurry digestate, rapeseed meal, and compost at three different doses (0.1, 0.25 and 0.5% w/w and incubated for 30 days at 20 ºC. During incubation, soil CO2 and N2O emissions, K2SO4 extractable organic C, N, NH4+, NO3- and P, soil microbial biomass and some enzymatic activities were determined. Results obtained showed that rapeseed meal and pig slurry are best suited to improve soil chemical and biological fertility, while compost is more appropriate for the enhancement of soil organic matter content and to promote soil C sequestration.

  3. Mechanism of acetaldehyde-induced deactivation of microbial lipases

    Directory of Open Access Journals (Sweden)

    Jaeger Karl E

    2011-02-01

    Full Text Available Abstract Background Microbial lipases represent the most important class of biocatalysts used for a wealth of applications in organic synthesis. An often applied reaction is the lipase-catalyzed transesterification of vinyl esters and alcohols resulting in the formation of acetaldehyde which is known to deactivate microbial lipases, presumably by structural changes caused by initial Schiff-base formation at solvent accessible lysine residues. Previous studies showed that several lipases were sensitive toward acetaldehyde deactivation whereas others were insensitive; however, a general explanation of the acetaldehyde-induced inactivation mechanism is missing. Results Based on five microbial lipases from Candida rugosa, Rhizopus oryzae, Pseudomonas fluorescens and Bacillus subtilis we demonstrate that the protonation state of lysine ε-amino groups is decisive for their sensitivity toward acetaldehyde. Analysis of the diverse modification products of Bacillus subtilis lipases in the presence of acetaldehyde revealed several stable products such as α,β-unsaturated polyenals, which result from base and/or amino acid catalyzed aldol condensation of acetaldehyde. Our studies indicate that these products induce the formation of stable Michael-adducts at solvent-accessible amino acids and thus lead to enzyme deactivation. Further, our results indicate Schiff-base formation with acetaldehyde to be involved in crosslinking of lipase molecules. Conclusions Differences in stability observed with various commercially available microbial lipases most probably result from different purification procedures carried out by the respective manufacturers. We observed that the pH of the buffer used prior to lyophilization of the enzyme sample is of utmost importance. The mechanism of acetaldehyde-induced deactivation of microbial lipases involves the generation of α,β-unsaturated polyenals from acetaldehyde which subsequently form stable Michael-adducts with the

  4. Isotopic insights into microbial sulfur cycling in oil reservoirs

    Directory of Open Access Journals (Sweden)

    Christopher G Hubbard

    2014-09-01

    Full Text Available Microbial sulfate reduction in oil reservoirs (biosouring is often associated with secondary oil production where seawater containing high sulfate concentrations (~28 mM is injected into a reservoir to maintain pressure and displace oil. The sulfide generated from biosouring can cause corrosion of infrastructure, health exposure risks, and higher production costs. Isotope monitoring is a promising approach for understanding microbial sulfur cycling in reservoirs, enabling early detection of biosouring, and understanding the impact of souring. Microbial sulfate reduction is known to result in large shifts in the sulfur and oxygen isotope compositions of the residual sulfate, which can be distinguished from other processes that may be occurring in oil reservoirs, such as precipitation of sulfate and sulfide minerals. Key to the success of this method is using the appropriate isotopic fractionation factors for the conditions and processes being monitored. For a set of batch incubation experiments using a mixed microbial culture with crude oil as the electron donor, we measured a sulfur fractionation factor for sulfate reduction of -30‰. We have incorporated this result into a simplified 1D reservoir reactive transport model to highlight how isotopes can help discriminate between biotic and abiotic processes affecting sulfate and sulfide concentrations. Modeling results suggest that monitoring sulfate isotopes can provide an early indication of souring for reservoirs with reactive iron minerals that can remove the produced sulfide, especially when sulfate reduction occurs in the mixing zone between formation waters containing elevated concentrations of volatile fatty acids and injection water containing elevated sulfate. In addition, we examine the role of reservoir thermal, geochemical, hydrological, operational and microbiological conditions in determining microbial souring dynamics and hence the anticipated isotopic signatures.

  5. Microbial sensor for drug susceptibility testing of Mycobacterium tuberculosis.

    Science.gov (United States)

    Zhang, Z-T; Wang, D-B; Li, C-Y; Deng, J-Y; Zhang, J-B; Bi, L-J; Zhang, X-E

    2018-01-01

    Drug susceptibility testing (DST) of clinical isolates of Mycobacterium tuberculosis is critical in treating tuberculosis. We demonstrate the possibility of using a microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. The sensor is made of an oxygen electrode with M. tuberculosis cells attached to its surface. This sensor monitors the residual oxygen consumption of M. tuberculosis cells after treatment with anti-TB drugs with glycerine as a carbon source. In principle, after drug pretreatment for 4-5 days, the response differences between the sensors made of drug-sensitive isolates are distinguishable from the sensors made of drug-resistant isolates. The susceptibility of the M. tuberculosis H37Ra strain, its mutants and 35 clinical isolates to six common anti-TB drugs: rifampicin, isoniazid, streptomycin, ethambutol, levofloxacin and para-aminosalicylic acid were tested using the proposed method. The results agreed well with the gold standard method (LJ) and were determined in significantly less time. The whole procedure takes approximately 11 days and therefore has the potential to inform clinical decisions. To our knowledge, this is the first study that demonstrates the possible application of a dissolved oxygen electrode-based microbial sensor in M. tuberculosis drug resistance testing. This study used the microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. The overall detection result of the microbial sensor agreed well with that of the conventional LJ proportion method and takes less time than the existing phenotypic methods. In future studies, we will build an O 2 electrode array microbial sensor reactor to enable a high-throughput drug resistance analysis. © 2017 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd on behalf of The Society for Applied Microbiology.

  6. Introduction to number theory

    CERN Document Server

    Vazzana, Anthony; Garth, David

    2007-01-01

    One of the oldest branches of mathematics, number theory is a vast field devoted to studying the properties of whole numbers. Offering a flexible format for a one- or two-semester course, Introduction to Number Theory uses worked examples, numerous exercises, and two popular software packages to describe a diverse array of number theory topics.

  7. Building Numbers from Primes

    Science.gov (United States)

    Burkhart, Jerry

    2009-01-01

    Prime numbers are often described as the "building blocks" of natural numbers. This article shows how the author and his students took this idea literally by using prime factorizations to build numbers with blocks. In this activity, students explore many concepts of number theory, including the relationship between greatest common factors and…

  8. Lifetime and residual strength of materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1997-01-01

    The DVM-theory (Damaged Viscoelastic Material) previously developed by the author to predict lifetime of wood subjected to static loads is further developed in this paper such that harmonic load variations can also be considered. Lifetime (real time or number of cycles) is predicted as a function...... of load amplitude, load average, fractional time under maximum load, and load frequency.The analysis includes prediction of residual strength (re-cycle strength) during the process of load cycling. It is concluded that number of cycles to failure is a very poor design criterion. It is demonstrated how...... the theory developed can be generalized also to consider non-harmonic load variations.Algorithms are presented for design purposes which may be suggested as qualified alternatives to the Palmgren-Miner's methods normally used in fatigue analysis of materials under arbitrary load variations. Prediction...

  9. In-Drift Microbial Communities

    International Nuclear Information System (INIS)

    Jolley, D.

    2000-01-01

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses

  10. In-Drift Microbial Communities

    Energy Technology Data Exchange (ETDEWEB)

    D. Jolley

    2000-11-09

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses.

  11. Microbial production of biovanillin

    Directory of Open Access Journals (Sweden)

    A. Converti

    2010-10-01

    Full Text Available This review aims at providing an overview on the microbial production of vanillin, a new alternative method for the production of this important flavor of the food industry, which has the potential to become economically competitive in the next future. After a brief description of the applications of vanillin in different industrial sectors and of its physicochemical properties, we described the traditional ways of providing vanillin, specifically extraction and chemical synthesis (mainly oxidation and compared them with the new biotechnological options, i.e., biotransformations of caffeic acid, veratraldehyde and mainly ferulic acid. In the second part of the review, emphasis has been addressed to the factors most influencing the bioproduction of vanillin, specifically the age of inoculum, pH, temperature, type of co-substrate, as well as the inhibitory effects exerted either by excess substrate or product. The final part of the work summarized the downstream processes and the related unit operations involved in the recovery of vanillin from the bioconversion medium.

  12. Microbial production of biovanillin.

    Science.gov (United States)

    Converti, A; Aliakbarian, B; Domínguez, J M; Bustos Vázquez, G; Perego, P

    2010-07-01

    This review aims at providing an overview on the microbial production of vanillin, a new alternative method for the production of this important flavor of the food industry, which has the potential to become economically competitive in the next future. After a brief description of the applications of vanillin in different industrial sectors and of its physicochemical properties, we described the traditional ways of providing vanillin, specifically extraction and chemical synthesis (mainly oxidation) and compared them with the new biotechnological options, i.e., biotransformations of caffeic acid, veratraldehyde and mainly ferulic acid. In the second part of the review, emphasis has been addressed to the factors most influencing the bioproduction of vanillin, specifically the age of inoculum, pH, temperature, type of co-substrate, as well as the inhibitory effects exerted either by excess substrate or product. The final part of the work summarized the downstream processes and the related unit operations involved in the recovery of vanillin from the bioconversion medium.

  13. Microbial Transformation of Arsenic

    Science.gov (United States)

    Stolz, J. F.

    2004-12-01

    Whether the source is natural or anthropogenic, it has become evident that arsenic is readily transformed by a great diversity of microbial species and has a robust biogeochemical cycle. Arsenic cycling primarily involves the oxidation of As(III) and the reduction of As(V). Over thirty arsenite oxidizing prokaryotes have been reported and include alpha, beta, and gamma Proteobacteria , Deinocci and Crenarchaeota. At least twenty species of arsenate-respiring prokaryotes are now known and include Crenarchaeota, thermophilic bacteria, low and high G+C gram positive bacteria, and gamma, delta, and epsilon Proteobacteria. These organisms are metabolically diverse, and depending on the species, capable of using other terminal electron acceptors (e.g., nitrate, selenate, fumarate, sulfate). In addition to inorganic forms (e.g., sodium arsenate) organoarsenicals can be utilized as a substrate. The feed additive roxarsone (3-nitro-4-hydroxyphenyl arsonic acid) has been shown to readily degrade leading to the release of inorganic arsenic (e.g., As(V)). Degradation proceeds via the cleavage of the arsenate functional group or the reduction of the nitro functional group and deamination. The rapid degradation (within 3 days) of roxarsone by Clostridium sp. strain OhILAs appears to follow the latter pathway and may involve Stickland reactions. The activities of these organisms affect the speciation and mobilization of arsenic, ultimately impacting water quality.

  14. Microbial hydroxylation of acetylaminosteroids.

    Science.gov (United States)

    Holland, H L; Lakshmaiah, G; Ruddock, P L

    1998-09-01

    An investigation of the microbial biotransformation of a range of 3 beta-, 17 beta-, and 20-acetylamino C18 to C21 steroids by microorganisms known to hydroxylate conventional steroids has been undertaken, using Aspergillus ochraceus, Bacillus megaterium, Curvularia lunata, and Rhizoputus arrhizus. A. ochraceus and B. megaterium gave products of 11 alpha- and 15 beta-hydroxylation, respectively. In the case of C. lunata, the products were predominantly those of this organism's normal C-11 beta- and C-14 alpha-hydroxylating pathways, but in one instance, 3 beta-acetylamino-7 alpha-hydroxy-5 alpha-androstan-17-one, appeared to results from direction of the site of hydroxylation by the substitution pattern of the substrate. The products from R. arrhizus generally corresponded to those previously obtained from normal steroids of similar skeleton, with 6 beta- 11 alpha-hydroxylation predominating, but again the sites of hydroxylation and the range of hydroxylated products were found to depend on the substitution pattern of the substrate.

  15. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1984-01-01

    A new process for recovery of plutonium and americium from pyrochemical waste has been demonstrated. It is based on chloride solution anion exchange at low acidity, which eliminates corrosive HCl fumes. Developmental experiments of the process flowsheet concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 = from high chloride-low acid solution. Americium and other metals are washed from the ion exchange column with 1N HNO 3 -4.8M NaCl. The plutonium is recovered, after elution, via hydroxide precipitation, while the americium is recovered via NaHCO 3 precipitation. All filtrates from the process are discardable as low-level contaminated waste. Production-scale experiments are now in progress for MSE residues. Flow sheets for actinide recovery from electrorefining and direct oxide reduction residues are presented and discussed

  16. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1985-05-01

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 2- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO 3 -4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO 3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  17. Alternatives to crop residues for soil amendment

    OpenAIRE

    Powell, J.M.; Unger, P.W.

    1997-01-01

    Metadata only record In semiarid agroecosystems, crop residues can provide important benefits of soil and water conservation, nutrient cycling, and improved subsequent crop yields. However, there are frequently multiple competing uses for residues, including animal forage, fuel, and construction material. This chapter discusses the various uses of crop residues and examines alternative soil amendments when crop residues cannot be left on the soil.

  18. The Biogeographic Pattern of Microbial Functional Genes along an Altitudinal Gradient of the Tibetan Pasture

    Directory of Open Access Journals (Sweden)

    Qi Qi

    2017-06-01

    Full Text Available As the highest place of the world, the Tibetan plateau is a fragile ecosystem. Given the importance of microbial communities in driving soil nutrient cycling, it is of interest to document the microbial biogeographic pattern here. We adopted a microarray-based tool named GeoChip 4.0 to investigate grassland microbial functional genes along an elevation gradient from 3200 to 3800 m above sea level open to free grazing by local herdsmen and wild animals. Interestingly, microbial functional diversities increase with elevation, so does the relative abundances of genes associated with carbon degradation, nitrogen cycling, methane production, cold shock and oxygen limitation. The range of Shannon diversities (10.27–10.58 showed considerably smaller variation than what was previously observed at ungrazed sites nearby (9.95–10.65, suggesting the important role of livestock grazing on microbial diversities. Closer examination showed that the dissimilarity of microbial community at our study sites increased with elevations, revealing an elevation-decay relationship of microbial functional genes. Both microbial functional diversity and the number of unique genes increased with elevations. Furthermore, we detected a tight linkage of greenhouse gas (CO2 and relative abundances of carbon cycling genes. Our biogeographic study provides insights on microbial functional diversity and soil biogeochemical cycling in Tibetan pastures.

  19. The Biogeographic Pattern of Microbial Functional Genes along an Altitudinal Gradient of the Tibetan Pasture

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Qi; Zhao, Mengxin; Wang, Shiping; Ma, Xingyu; Wang, Yuxuan; Gao, Ying; Lin, Qiaoyan; Li, Xiangzhen; Gu, Baohua; Li, Guoxue; Zhou, Jizhong; Yang, Yunfeng

    2017-06-13

    As the highest place of the world, the Tibetan plateau is a fragile ecosystem. Given the importance of microbial communities in driving soil nutrient cycling, it is of interest to document the microbial biogeographic pattern here. We adopted a microarray-based tool named GeoChip 4.0 to investigate grassland microbial functional genes along an elevation gradient from 3200 to 3800 m above sea level open to free grazing by local herdsmen and wild animals. Interestingly, microbial functional diversities increase with elevation, so does the relative abundances of genes associated with carbon degradation, nitrogen cycling, methane production, cold shock and oxygen limitation. The range of Shannon diversities (10.27–10.58) showed considerably smaller variation than what was previously observed at ungrazed sites nearby (9.95–10.65), suggesting the important role of livestock grazing on microbial diversities. Closer examination showed that the dissimilarity of microbial community at our study sites increased with elevations, revealing an elevation-decay relationship of microbial functional genes. Both microbial functional diversity and the number of unique genes increased with elevations. Furthermore, we detected a tight linkage of greenhouse gas (CO2) and relative abundances of carbon cycling genes. Our biogeographic study provides insights on microbial functional diversity and soil biogeochemical cycling in Tibetan pastures.

  20. Leaching From Biomass Gasification Residues

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.

    2011-01-01

    The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled with geoche......The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled...

  1. Carbaryl residues in maize products

    International Nuclear Information System (INIS)

    Zayed, S.M.A.D.; Mansour, S.A.; Mostafa, I.Y.; Hassan, A.

    1976-01-01

    The 14 C-labelled insecticide carbaryl was synthesized from [1- 14 C]-1-naphthol at a specific activity of 3.18mCig -1 . Maize plants were treated with the labelled insecticide under simulated conditions of agricultural practice. Mature plants were harvested and studied for distribution of total residues in untreated grains as popularly roasted and consumed, and in the corn oil and corn germ products. Total residues found under these conditions in the respective products were 0.2, 0.1, 0.45 and 0.16ppm. (author)

  2. Combinatorial construction of toric residues

    OpenAIRE

    Khetan, Amit; Soprounov, Ivan

    2004-01-01

    The toric residue is a map depending on n+1 semi-ample divisors on a complete toric variety of dimension n. It appears in a variety of contexts such as sparse polynomial systems, mirror symmetry, and GKZ hypergeometric functions. In this paper we investigate the problem of finding an explicit element whose toric residue is equal to one. Such an element is shown to exist if and only if the associated polytopes are essential. We reduce the problem to finding a collection of partitions of the la...

  3. Effects of Bio-char on Soil Microbes in Herbicide Residual Soils

    Directory of Open Access Journals (Sweden)

    WANG Gen-lin

    2015-10-01

    Full Text Available Effects of biological carbon (bio-char on soil microbial community were studied by pot experiments simulating long residual herbicide residues in soil environment, which clarifed the improvement of biochar and its structural properties on soil microenvironment. The results showed that fungi and actinomycetes had the same effect tendency within 0~0.72 mg·kg-1 in clomazone residue which increased the role of stimulation with crop growth process prolonged, especially in high residue treatment, but strong inhibitory effect on bacteria community was occured early which returned to normal until sugar beet growth to fiftieth day. Soil fungi community decreased with bio-char adding, but had no significant difference with the control. When clomazone residue in soil was below 0.24 mg·kg-1, soil actinomycetes community was higher than control without bio-char, bacteria increased first and then reduced after adding carbon as below 0.12 mg·kg-1. Biochar was ‘deep hole’ structure containing C, O, S and other elements. The results showed that a certain concentration clomazone residue in soil would stimulate soil fungi and actinomycetes to grow. After adding the biochar, the inhibition effect of high herbicides residual on bacterial would be alleviated.

  4. Composition and physiological profiling of sprout-associated microbial communities

    Science.gov (United States)

    Matos, Anabelle; Garland, Jay L.; Fett, William F.

    2002-01-01

    The native microfloras of various types of sprouts (alfalfa, clover, sunflower, mung bean, and broccoli sprouts) were examined to assess the relative effects of sprout type and inoculum factors (i.e., sprout-growing facility, seed lot, and inoculation with sprout-derived inocula) on the microbial community structure of sprouts. Sprouts were sonicated for 7 min or hand shaken with glass beads for 2 min to recover native microfloras from the surface, and the resulting suspensions were diluted and plated. The culturable fraction was characterized by the density (log CFU/g), richness (e.g., number of types of bacteria), and diversity (e.g., microbial richness and evenness) of colonies on tryptic soy agar plates incubated for 48 h at 30 degrees C. The relative similarity between sprout-associated microbial communities was assessed with the use of community-level physiological profiles (CLPPs) based on patterns of utilization of 95 separate carbon sources. Aerobic plate counts of 7.96 +/- 0.91 log CFU/g of sprout tissue (fresh weight) were observed, with no statistically significant differences in microbial cell density, richness, or diversity due to sprout type, sprout-growing facility, or seed lot. CLPP analyses revealed that the microbial communities associated with alfalfa and clover sprouts are more similar than those associated with the other sprout types tested. Variability among sprout types was more extensive than any differences between microbial communities associated with alfalfa and clover sprouts from different sprout-growing facilities and seed lots. These results indicate that the subsequent testing of biocontrol agents should focus on similar organisms for alfalfa and clover, but alternative types may be most suitable for the other sprout types tested. The inoculation of alfalfa sprouts with communities derived from various sprout types had a significant, source-independent effect on microbial community structure, indicating that the process of

  5. Algebraic number theory

    CERN Document Server

    Jarvis, Frazer

    2014-01-01

    The technical difficulties of algebraic number theory often make this subject appear difficult to beginners. This undergraduate textbook provides a welcome solution to these problems as it provides an approachable and thorough introduction to the topic. Algebraic Number Theory takes the reader from unique factorisation in the integers through to the modern-day number field sieve. The first few chapters consider the importance of arithmetic in fields larger than the rational numbers. Whilst some results generalise well, the unique factorisation of the integers in these more general number fields often fail. Algebraic number theory aims to overcome this problem. Most examples are taken from quadratic fields, for which calculations are easy to perform. The middle section considers more general theory and results for number fields, and the book concludes with some topics which are more likely to be suitable for advanced students, namely, the analytic class number formula and the number field sieve. This is the fi...

  6. An Overview on Recent Progress in Electrochemical Biosensors for Antimicrobial Drug Residues in Animal-Derived Food

    Science.gov (United States)

    Majdinasab, Marjan; Yaqub, Mustansara; Rahim, Abdur; Catanante, Gaelle; Hayat, Akhtar; Marty, Jean Louis

    2017-01-01

    Anti-microbial drugs are widely employed for the treatment and cure of diseases in animals, promotion of animal growth, and feed efficiency. However, the scientific literature has indicated the possible presence of antimicrobial drug residues in animal-derived food, making it one of the key public concerns for food safety. Therefore, it is highly desirable to design fast and accurate methodologies to monitor antimicrobial drug residues in animal-derived food. Legislation is in place in many countries to ensure antimicrobial drug residue quantities are less than the maximum residue limits (MRL) defined on the basis of food safety. In this context, the recent years have witnessed a special interest in the field of electrochemical biosensors for food safety, based on their unique analytical features. This review article is focused on the recent progress in the domain of electrochemical biosensors to monitor antimicrobial drug residues in animal-derived food. PMID:28837093

  7. Utilizing novel diversity estimators to quantify multiple dimensions of microbial biodiversity across domains.

    Science.gov (United States)

    Doll, Hannah M; Armitage, David W; Daly, Rebecca A; Emerson, Joanne B; Goltsman, Daniela S Aliaga; Yelton, Alexis P; Kerekes, Jennifer; Firestone, Mary K; Potts, Matthew D

    2013-11-15

    Microbial ecologists often employ methods from classical community ecology to analyze microbial community diversity. However, these methods have limitations because microbial communities differ from macro-organismal communities in key ways. This study sought to quantify microbial diversity using methods that are better suited for data spanning multiple domains of life and dimensions of diversity. Diversity profiles are one novel, promising way to analyze microbial datasets. Diversity profiles encompass many other indices, provide effective numbers of diversity (mathematical generalizations of previous indices that better convey the magnitude of differences in diversity), and can incorporate taxa similarity information. To explore whether these profiles change interpretations of microbial datasets, diversity profiles were calculated for four microbial datasets from different environments spanning all domains of life as well as viruses. Both similarity-based profiles that incorporated phylogenetic relatedness and naïve (not similarity-based) profiles were calculated. Simulated datasets were used to examine the robustness of diversity profiles to varying phylogenetic topology and community composition. Diversity profiles provided insights into microbial datasets that were not detectable with classical univariate diversity metrics. For all datasets analyzed, there were key distinctions between calculations that incorporated phylogenetic diversity as a measure of taxa similarity and naïve calculations. The profiles also provided information about the effects of rare species on diversity calculations. Additionally, diversity profiles were used to examine thousands of simulated microbial communities, showing that similarity-based and naïve diversity profiles only agreed approximately 50% of the time in their classification of which sample was most diverse. This is a strong argument for incorporating similarity information and calculating diversity with a range of

  8. p-adic numbers

    OpenAIRE

    Grešak, Rozalija

    2015-01-01

    The field of real numbers is usually constructed using Dedekind cuts. In these thesis we focus on the construction of the field of real numbers using metric completion of rational numbers using Cauchy sequences. In a similar manner we construct the field of p-adic numbers, describe some of their basic and topological properties. We follow by a construction of complex p-adic numbers and we compare them with the ordinary complex numbers. We conclude the thesis by giving a motivation for the int...

  9. Model-checking techniques based on cumulative residuals.

    Science.gov (United States)

    Lin, D Y; Wei, L J; Ying, Z

    2002-03-01

    Residuals have long been used for graphical and numerical examinations of the adequacy of regression models. Conventional residual analysis based on the plots of raw residuals or their smoothed curves is highly subjective, whereas most numerical goodness-of-fit tests provide little information about the nature of model misspecification. In this paper, we develop objective and informative model-checking techniques by taking the cumulative sums of residuals over certain coordinates (e.g., covariates or fitted values) or by considering some related aggregates of residuals, such as moving sums and moving averages. For a variety of statistical models and data structures, including generalized linear models with independent or dependent observations, the distributions of these stochastic processes tinder the assumed model can be approximated by the distributions of certain zero-mean Gaussian processes whose realizations can be easily generated by computer simulation. Each observed process can then be compared, both graphically and numerically, with a number of realizations from the Gaussian process. Such comparisons enable one to assess objectively whether a trend seen in a residual plot reflects model misspecification or natural variation. The proposed techniques are particularly useful in checking the functional form of a covariate and the link function. Illustrations with several medical studies are provided.

  10. ResBoost: characterizing and predicting catalytic residues in enzymes

    Directory of Open Access Journals (Sweden)

    Freund Yoav

    2009-06-01

    Full Text Available Abstract Background Identifying the catalytic residues in enzymes can aid in understanding the molecular basis of an enzyme's function and has significant implications for designing new drugs, identifying genetic disorders, and engineering proteins with novel functions. Since experimentally determining catalytic sites is expensive, better computational methods for identifying catalytic residues are needed. Results We propose ResBoost, a new computational method to learn characteristics of catalytic residues. The method effectively selects and combines rules of thumb into a simple, easily interpretable logical expression that can be used for prediction. We formally define the rules of thumb that are often used to narrow the list of candidate residues, including residue evolutionary conservation, 3D clustering, solvent accessibility, and hydrophilicity. ResBoost builds on two methods from machine learning, the AdaBoost algorithm and Alternating Decision Trees, and provides precise control over the inherent trade-off between sensitivity and specificity. We evaluated ResBoost using cross-validation on a dataset of 100 enzymes from the hand-curated Catalytic Site Atlas (CSA. Conclusion ResBoost achieved 85% sensitivity for a 9.8% false positive rate and 73% sensitivity for a 5.7% false positive rate. ResBoost reduces the number of false positives by up to 56% compared to the use of evolutionary conservation scoring alone. We also illustrate the ability of ResBoost to identify recently validated catalytic residues not listed in the CSA.

  11. The microbial ecology of wine grape berries.

    Science.gov (United States)

    Barata, A; Malfeito-Ferreira, M; Loureiro, V

    2012-02-15

    ., Burkholderia spp., Serratia spp., Staphylococcus spp., among others, have been isolated from grapes but do not have the ability to grow in wines. Saprophytic moulds, like Botrytis cinerea, causing grey rot, or Aspergillus spp., possibly producing ochratoxin, are only active in the vineyard, although their metabolites may affect wine quality during grape processing. The impact of damaged grapes in yeast ecology has been underestimated mostly because of inaccurate grape sampling. Injured berries hidden in apparently sound bunches explain the recovery of a higher number of species when whole bunches are picked. Grape health status is the main factor affecting the microbial ecology of grapes, increasing both microbial numbers and species diversity. Therefore, the influence of abiotic (e.g. climate, rain, hail), biotic (e.g. insects, birds, phytopathogenic and saprophytic moulds) and viticultural (e.g. fungicides) factors is dependent on their primary damaging effect. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Evaluation of Some Pesticide Residues in Stored Beans in Jos ...

    African Journals Online (AJOL)

    Humans utilize pesticides through agricultural practice to protect crops against destructive pests but pesticide use has been associated with human and environmental toxic effects. Its presence in food is disturbing considering the increasing number of toxicity it causes. Pesticide residues are lipophylic in nature and ...

  13. Modeling of CMUTs with Multiple Anisotropic Layers and Residual Stress

    DEFF Research Database (Denmark)

    Engholm, Mathias; Thomsen, Erik Vilain

    2014-01-01

    Usually the analytical approach for modeling CMUTs uses the single layer plate equation to obtain the deflection and does not take anisotropy and residual stress into account. A highly accurate model is developed for analytical characterization of CMUTs taking an arbitrary number of layers...

  14. Antimicrobial residues in tissues and eggs of laying hens at Chittagong, Bangladesh

    Directory of Open Access Journals (Sweden)

    Ariful Islam

    2016-12-01

    Full Text Available Aim: Antimicrobial residue in animal food products is an important index of food safety. Antimicrobial residues could result from chemotherapeutic or chemoprophylactic use of drugs in food animals. This occurrence of residue in animal food products has received enormous worldwide attention from some local, international, and public health agencies. A crosssectional study was conducted from July to December 2009 to detect the antibiotic residues in tissues and eggs of laying hens at Chittagong of Bangladesh. Materials and Methods: Microbial inhibition test (MIT and thin layer chromatography (TLC methods were used to detect antibacterial residues in poultry tissues (liver, kidney, breast, and thigh muscles and eggs. The bacteria and pH of the MIT method were as follows: Bacillus subtilis on test agar medium with a pH of 7.2, Bacillus cereus with a pH of 6.0, and Escherichia coli at pH with an 8.0. Results: The overall prevalence of antibiotic residues detected by MIT was 64% in liver, 63% in kidney, 56% in breast muscle, 50% in thigh muscle, and 60% in eggs. There was significant variation in results between MIT and TLC (p<0.05. Tetracycline residues were found in 48% in liver, 24% in kidneys, 20% in thigh muscles, 26% in breast muscles, and 36% in eggs. Ciprofloxacin residues were found 46% in liver, 42% in kidneys, 34% in thigh muscles, 30% in breast muscles, and 30% in eggs. Enrofloxacin residues were found 40% in livers, 36% in kidneys, 24% in thigh muscles, 20% in breast muscles, and 26% in eggs. Amoxicillin residues were found 48% in livers, 30% in kidneys, 26% in thigh muscles, 22% in breast muscles, and 24% in eggs. The most frequently detected antibiotic residues by both MIT and TLC were found in liver tissue, tetracycline (48%, ciprofloxacin (46%, enrofloxacin (40%, and amoxicillin (42% were found in liver. Breast muscle tissue was least likely to contain antibiotic residues (24%. Tetracycline (p=0.01 and amoxicillin (p=0.03 residues had

  15. On the number of special numbers

    Indian Academy of Sciences (India)

    We now apply the theory of the Thue equation to obtain an effective bound on m. Indeed, by Lemma 3.2, we can write m2 = ba3 and m2 − 4 = cd3 with b, c cubefree. By the above, both b, c are bounded since they are cubefree and all their prime factors are less than e63727. Now we have a finite number of. Thue equations:.

  16. Functional diversity of terrestrial microbial decomposers and their substrates.

    Science.gov (United States)

    Hättenschwiler, Stephan; Fromin, Nathalie; Barantal, Sandra

    2011-05-01

    The relationship between biodiversity and biogeochemical processes gained much interest in light of the rapidly decreasing biodiversity worldwide. In this article, we discuss the current status, challenges and prospects of functional concepts to plant litter diversity and microbial decomposer diversity. We also evaluate whether these concepts permit a better understanding of how biodiversity is linked to litter decomposition as a key ecosystem process influencing carbon and nutrient cycles. Based on a literature survey, we show that plant litter and microbial diversity matters for decomposition, but that considering numbers of taxonomic units appears overall as little relevant and less useful than functional diversity. However, despite easily available functional litter traits and the well-established theoretical framework for functional litter diversity, the impact of functional litter diversity on decomposition is not yet well enough explored. Defining functional diversity of microorganisms remains one of the biggest challenges for functional approaches to microbial diversity. Recent developments in microarray and metagenomics technology offer promising possibilities in the assessment of the functional structure of microbial communities. This might allow significant progress in measuring functional microbial diversity and ultimately in our ability to predict consequences of biodiversity loss in the decomposer system for biogeochemical processes. Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  17. Microbial Biofilm and Bacterial Contamination on Pig Carcasses

    Directory of Open Access Journals (Sweden)

    Adriana Morar

    2010-10-01

    Full Text Available The aim of this study was to emphasize the presence of biofilm on meat surfaces using epifluorescences microscopy and establishing the microbial contamination level by classical microbiological methods. The research was performed in a pork slaughterhouse. The presence of microbial biofilm and the level of contamination were performed on surfaces from pig carcasses and cut pieces. Clusters of microorganisms included in a biofilm matrix were found on the surface of carcasses on sternal region, coast region, coccigian region and on surfaces of cut pieces: chop, front of thighs. Microbial biofilm was present on carcasses and cut pieces at least 3 days length, in regions with high humidity and microbial contamination level ranged of 102- 103 cfu/ cm2. The microbial load of the surfaces was assessed using the following microbiological indicators: total viable count (TVC, the number of enterobacteria and Pseudomonas genus. The level of carcasses contamination ranged on average from 1.3 x 10 cfu/ cm2 (neck to 2.6 x 103 cfu/cm2 (front of pulp. The proportion of Enterobacteriaceae-positive samples was 60%, with a low level of contamination (less than 1 cfu/ cm2. Germs of the Pseudomonas genus were absent in all the analyzed samples.

  18. Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres

    KAUST Repository

    Gonzalez-Gil, Graciela

    2016-04-26

    Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0), insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20%) and Pseudomonadaceae (c.a.10%) were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (∼200 μm) of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano)spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS) analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.

  19. Determination of residual stress within complex-shaped coarse-grained cobalt-chrome biomedical castings

    OpenAIRE

    Conroy, Brian P; Tanner, David A

    2016-01-01

    peer-reviewed ASTM F75 femoral knee implant casting components distort during manufacture due to residual stress re-distribution or inducement. These castings pose a number of challenges for residual stress determination methods; they have a complex geometry, their micro-structure is inhomogeneous, they work-harden rapidly and they have a coarse, elastically-anisotropic grain structure. The contour method is anticipated to be the most promising residual stress determination technique. X-ra...

  20. Solidification process for sludge residue

    International Nuclear Information System (INIS)

    Pearce, K.L.

    1998-01-01

    This report investigates the solidification process used at 100-N Basin to solidify the N Basin sediment and assesses the N Basin process for application to the K Basin sludge residue material. This report also includes a discussion of a solidification process for stabilizing filters. The solidified matrix must be compatible with the Environmental Remediation Disposal Facility acceptance criteria

  1. Machine Arithmetic in Residual Classes,

    Science.gov (United States)

    1981-04-03

    rsmainder/residue, as this ascape /-nsues from thp determination of system. It can be. zaalizpd ;n the presence of th- arithmetic urit, which wor~s in thz sys...modules Nj. Page 417. Proof. Proof ascaps /ensues directly from the theorem of Gauss. Actually/really, since according to condition (py, qj)-=-. then

  2. Residual stress in polyethylene pipes

    Czech Academy of Sciences Publication Activity Database

    Poduška, Jan; Hutař, Pavel; Kučera, J.; Frank, A.; Sadílek, J.; Pinter, G.; Náhlík, Luboš

    2016-01-01

    Roč. 54, SEP (2016), s. 288-295 ISSN 0142-9418 R&D Projects: GA MŠk LM2015069; GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : polyethylene pipe * residual stress * ring slitting method * lifetime estimation Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.464, year: 2016

  3. Managing woodwaste: Yield from residue

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, E. [LNS Services, Inc., North Vancouver, British Columbia (Canada); Rayner, S. [Pacific Waste Energy Inc., Burnaby, British Columbia (Canada)

    1993-12-31

    Historically, the majority of sawmill waste has been burned or buried for the sole purpose of disposal. In most jurisdictions, environmental legislation will prohibit, or render uneconomic, these practices. Many reports have been prepared to describe the forest industry`s residue and its environmental effect; although these help those looking for industry-wide or regional solutions, such as electricity generation, they have limited value for the mill manager, who has the on-hands responsibility for generation and disposal of the waste. If the mill manager can evaluate waste streams and break them down into their usable components, he can find niche market solutions for portions of the plant residue and redirect waste to poor/no-return, rather than disposal-cost, end uses. In the modern mill, residue is collected at the individual machine centre by waste conveyors that combine and mix sawdust, shavings, bark, etc. and send the result to the hog-fuel pile. The mill waste system should be analyzed to determine the measures that can improve the quality of residues and determine the volumes of any particular category before the mixing, mentioned above, occurs. After this analysis, the mill may find a niche market for a portion of its woodwaste.

  4. Leptogenesis and residual CP symmetry

    International Nuclear Information System (INIS)

    Chen, Peng; Ding, Gui-Jun; King, Stephen F.

    2016-01-01

    We discuss flavour dependent leptogenesis in the framework of lepton flavour models based on discrete flavour and CP symmetries applied to the type-I seesaw model. Working in the flavour basis, we analyse the case of two general residual CP symmetries in the neutrino sector, which corresponds to all possible semi-direct models based on a preserved Z 2 in the neutrino sector, together with a CP symmetry, which constrains the PMNS matrix up to a single free parameter which may be fixed by the reactor angle. We systematically study and classify this case for all possible residual CP symmetries, and show that the R-matrix is tightly constrained up to a single free parameter, with only certain forms being consistent with successful leptogenesis, leading to possible connections between leptogenesis and PMNS parameters. The formalism is completely general in the sense that the two residual CP symmetries could result from any high energy discrete flavour theory which respects any CP symmetry. As a simple example, we apply the formalism to a high energy S 4 flavour symmetry with a generalized CP symmetry, broken to two residual CP symmetries in the neutrino sector, recovering familiar results for PMNS predictions, together with new results for flavour dependent leptogenesis.

  5. Solow Residuals Without Capital Stocks

    DEFF Research Database (Denmark)

    Burda, Michael C.; Severgnini, Battista

    2014-01-01

    We use synthetic data generated by a prototypical stochastic growth model to assess the accuracy of the Solow residual (Solow, 1957) as a measure of total factor productivity (TFP) growth when the capital stock in use is measured with error. We propose two alternative measurements based on current...

  6. Hawaiian Number Systems.

    Science.gov (United States)

    Hughes, Barnabas

    1982-01-01

    The history of Hawaiian number systems is examined, and answers to questions regarding Hawaiian number words, including their origin and factors that influenced their development, are covered. A brief guide for pronouncing Hawaiian words is also provided. (MP)

  7. Making decisions from numbers

    Energy Technology Data Exchange (ETDEWEB)

    Somers, E.

    1987-03-01

    Regulatory agencies require numbers to provide health protection. The manner in which these numbers are derived from animal experiments and human epidemiology is considered together with the limitations and inadequacies of these numbers. Some recent examples of risk assessment in Canada are given including asbestos, drinking water, and indoor air quality. The value of these numbers in providing a measure of the hazard in a wider perspective is stressed, although they can never be the sole determinant of public policy.

  8. Crystal structure of microbial transglutaminase from Streptoverticillium mobaraense.

    Science.gov (United States)

    Kashiwagi, Tatsuki; Yokoyama, Kei-Ichi; Ishikawa, Kohki; Ono, Kunio; Ejima, Daisuke; Matsui, Hiroshi; Suzuki, Ei-ichiro

    2002-11-15

    The crystal structure of a microbial transglutaminase from Streptoverticillium mobaraense has been determined at 2.4 A resolution. The protein folds into a plate-like shape, and has one deep cleft at the edge of the molecule. Its overall structure is completely different from that of the factor XIII-like transglutaminase, which possesses a cysteine protease-like catalytic triad. The catalytic residue, Cys(64), exists at the bottom of the cleft. Asp(255) resides at the position nearest to Cys(64) and is also adjacent to His(274). Interestingly, Cys(64), Asp(255), and His(274) superimpose well on the catalytic triad "Cys-His-Asp" of the factor XIII-like transglutaminase, in this order. The secondary structure frameworks around these residues are also similar to each other. These results imply that both transglutaminases are related by convergent evolution; however, the microbial transglutaminase has developed a novel catalytic mechanism specialized for the cross-linking reaction. The structure accounts well for the catalytic mechanism, in which Asp(255) is considered to be enzymatically essential, as well as for the causes of the higher reaction rate, the broader substrate specificity, and the lower deamidation activity of this enzyme.

  9. Analytic number theory

    CERN Document Server

    Matsumoto, Kohji

    2002-01-01

    The book includes several survey articles on prime numbers, divisor problems, and Diophantine equations, as well as research papers on various aspects of analytic number theory such as additive problems, Diophantine approximations and the theory of zeta and L-function Audience Researchers and graduate students interested in recent development of number theory

  10. Safety-in-numbers

    DEFF Research Database (Denmark)

    Elvik, Rune; Bjørnskau, Torkel

    2017-01-01

    Highlights •26 studies of the safety-in-numbers effect are reviewed. •The existence of a safety-in-numbers effect is confirmed. •Results are consistent. •Causes of the safety-in-numbers effect are incompletely known....

  11. Microbiology Meets Archaeology: Soil Microbial Communities Reveal Different Human Activities at Archaic Monte Iato (Sixth Century BC).

    Science.gov (United States)

    Margesin, Rosa; Siles, José A; Cajthaml, Tomas; Öhlinger, Birgit; Kistler, Erich

    2017-05-01

    Microbial ecology has been recognized as useful in archaeological studies. At Archaic Monte Iato in Western Sicily, a native (indigenous) building was discovered. The objective of this study was the first examination of soil microbial communities related to this building. Soil samples were collected from archaeological layers at a ritual deposit (food waste disposal) in the main room and above the fireplace in the annex. Microbial soil characterization included abundance (cellular phospholipid fatty acids (PLFA), viable bacterial counts), activity (physiological profiles, enzyme activities of viable bacteria), diversity, and community structure (bacterial and fungal Illumina amplicon sequencing, identification of viable bacteria). PLFA-derived microbial abundance was lower in soils from the fireplace than in soils from the deposit; the opposite was observed with culturable bacteria. Microbial communities in soils from the fireplace had a higher ability to metabolize carboxylic and acetic acids, while those in soils from the deposit metabolized preferentially carbohydrates. The lower deposit layer was characterized by higher total microbial and bacterial abundance and bacterial richness and by a different carbohydrate metabolization profile compared to the upper deposit layer. Microbial community structures in the fireplace were similar and could be distinguished from those in the two deposit layers, which had different microbial communities. Our data confirmed our hypothesis that human consumption habits left traces on microbiota in the archaeological evidence; therefore, microbiological residues as part of the so-called ecofacts are, like artifacts, key indicators of consumer behavior in the past.

  12. MICROBIAL SURFACTANTS IN ENVIRONMENTAL TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2015-08-01

    Full Text Available It was shown literature and own experimental data concerning the use of microbial surface active glycolipids (rhamno-, sophoro- and trehalose lipids and lipopeptides for water and soil purification from oil and other hydrocarbons, removing toxic heavy metals (Cu2+, Cd2+, Ni2+, Pb2+, degradation of complex pollution (oil and other hydrocarbons with heavy metals, and the role of microbial surfactants in phytoremediation processes. The factors that limit the use of microbial surfactants in environmental technologies are discussed. Thus, at certain concentrations biosurfactant can exhibit antimicrobial properties and inhibit microorganisms destructing xenobiotics. Microbial biodegradability of surfactants may also reduce the effectiveness of bioremediation. Development of effective technologies using microbial surfactants should include the following steps: monitoring of contaminated sites to determine the nature of pollution and analysis of the autochthonous microbiota; determining the mode of surfactant introduction (exogenous addition of stimulation of surfactant synthesis by autochthonous microbiota; establishing an optimal concentration of surfactant to prevent exhibition of antimicrobial properties and rapid biodegradation; research both in laboratory and field conditions.

  13. Modeling microbial growth and dynamics.

    Science.gov (United States)

    Esser, Daniel S; Leveau, Johan H J; Meyer, Katrin M

    2015-11-01

    Modeling has become an important tool for widening our understanding of microbial growth in the context of applied microbiology and related to such processes as safe food production, wastewater treatment, bioremediation, or microbe-mediated mining. Various modeling techniques, such as primary, secondary and tertiary mathematical models, phenomenological models, mechanistic or kinetic models, reactive transport models, Bayesian network models, artificial neural networks, as well as agent-, individual-, and particle-based models have been applied to model microbial growth and activity in many applied fields. In this mini-review, we summarize the basic concepts of these models using examples and applications from food safety and wastewater treatment systems. We further review recent developments in other applied fields focusing on models that explicitly include spatial relationships. Using these examples, we point out the conceptual similarities across fields of application and encourage the combined use of different modeling techniques in hybrid models as well as their cross-disciplinary exchange. For instance, pattern-oriented modeling has its origin in ecology but may be employed to parameterize microbial growth models when experimental data are scarce. Models could also be used as virtual laboratories to optimize experimental design analogous to the virtual ecologist approach. Future microbial growth models will likely become more complex to benefit from the rich toolbox that is now available to microbial growth modelers.

  14. Microbial production of xylitol from xylose and L-arabinose: conversion of L-arabitol to xylitol using bacterial oxidoreductases

    Science.gov (United States)

    Microbial production of xylitol, using hemicellulosic biomass such as agricultural residues, is becoming more attractive for reducing its manufacturing cost. L-arabitol is a particular problem to xylitol production from hemicellulosic hydrolyzates that contain both xylose and L-arabinose because it...

  15. Evaluating the Metal Tolerance Capacity of Microbial Communities Isolated from Alberta Oil Sands Process Water

    Science.gov (United States)

    Frankel, Mathew L.; Demeter, Marc A.; Lemire, Joe A.; Turner, Raymond J.

    2016-01-01

    Anthropogenic activities have resulted in the intensified use of water resources. For example, open pit bitumen extraction by Canada’s oil sands operations uses an estimated volume of three barrels of water for every barrel of oil produced. The waste tailings–oil sands process water (OSPW)–are stored in holding ponds, and present an environmental concern as they are comprised of residual hydrocarbons and metals. Following the hypothesis that endogenous OSPW microbial communities have an enhanced tolerance to heavy metals, we tested the capacity of planktonic and biofilm populations from OSPW to withstand metal ion challenges, using Cupriavidus metallidurans, a known metal-resistant organism, for comparison. The toxicity of the metals toward biofilm and planktonic bacterial populations was determined by measuring the minimum biofilm inhibitory concentrations (MBICs) and planktonic minimum inhibitory concentrations (MICs) using the MBEC ™ assay. We observed that the OSPW community and C. metallidurans had similar tolerances to 22 different metals. While thiophillic elements (Te, Ag, Cd, Ni) were found to be most toxic, the OSPW consortia demonstrated higher tolerance to metals reported in tailings ponds (Al, Fe, Mo, Pb). Metal toxicity correlated with a number of physicochemical characteristics of the metals. Parameters reflecting metal-ligand affinities showed fewer and weaker correlations for the community compared to C. metallidurans, suggesting that the OSPW consortia may have developed tolerance mechanisms toward metals present in their environment. PMID:26849649

  16. Evaluating the Metal Tolerance Capacity of Microbial Communities Isolated from Alberta Oil Sands Process Water.

    Directory of Open Access Journals (Sweden)

    Mathew L Frankel

    Full Text Available Anthropogenic activities have resulted in the intensified use of water resources. For example, open pit bitumen extraction by Canada's oil sands operations uses an estimated volume of three barrels of water for every barrel of oil produced. The waste tailings-oil sands process water (OSPW-are stored in holding ponds, and present an environmental concern as they are comprised of residual hydrocarbons and metals. Following the hypothesis that endogenous OSPW microbial communities have an enhanced tolerance to heavy metals, we tested the capacity of planktonic and biofilm populations from OSPW to withstand metal ion challenges, using Cupriavidus metallidurans, a known metal-resistant organism, for comparison. The toxicity of the metals toward biofilm and planktonic bacterial populations was determined by measuring the minimum biofilm inhibitory concentrations (MBICs and planktonic minimum inhibitory concentrations (MICs using the MBEC ™ assay. We observed that the OSPW community and C. metallidurans had similar tolerances to 22 different metals. While thiophillic elements (Te, Ag, Cd, Ni were found to be most toxic, the OSPW consortia demonstrated higher tolerance to metals reported in tailings ponds (Al, Fe, Mo, Pb. Metal toxicity correlated with a number of physicochemical characteristics of the metals. Parameters reflecting metal-ligand affinities showed fewer and weaker correlations for the community compared to C. metallidurans, suggesting that the OSPW consortia may have developed tolerance mechanisms toward metals present in their environment.

  17. Differences in microbial community composition between injection and production water samples of water flooding petroleum reservoirs

    Directory of Open Access Journals (Sweden)

    P. K. Gao

    2015-06-01

    Full Text Available Microbial communities in injected water are expected to have significant influence on those of reservoir strata in long-term water flooding petroleum reservoirs. To investigate the similarities and differences in microbial communities in injected water and reservoir strata, high-throughput sequencing of microbial partial 16S rRNA of the water samples collected from the wellhead and downhole of injection wells, and from production wells in a homogeneous sandstone reservoir and a heterogeneous conglomerate reservoir were performed. The results indicate that a small number of microbial populations are shared between the water samples from the injection and production wells in the sandstone reservoir, whereas a large number of microbial populations are shared in the conglomerate reservoir. The bacterial and archaeal communities in the reservoir strata have high concentrations, which are similar to those in the injected water. However, microbial population abundance exhibited large differences between the water samples from the injection and production wells. The number of shared populations reflects the influence of microbial communities in injected water on those in reservoir strata to some extent, and show strong association with the unique variation of reservoir environments.

  18. Radioactive material in residues of health services residues

    International Nuclear Information System (INIS)

    Costa R, A. Jr.; Recio, J.C.

    2006-01-01

    The work presents the operational actions developed by the one organ responsible regulator for the control of the material use radioactive in Brazil. Starting from the appearance of coming radioactive material of hospitals and clinical with services of nuclear medicine, material that that is picked up and transported in specific trucks for the gathering of residuals of hospital origin, and guided one it manufactures of treatment of residuals of services of health, where they suffer radiological monitoring before to guide them for final deposition in sanitary embankment, in the city of Sao Paulo, Brazil. The appearance of this radioactive material exposes a possible one violation of the norms that govern the procedures and practices in that sector in the country. (Author)

  19. Asymptotic numbers: Pt.1

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1980-01-01

    The set of asymptotic numbers A as a system of generalized numbers including the system of real numbers R, as well as infinitely small (infinitesimals) and infinitely large numbers, is introduced. The detailed algebraic properties of A, which are unusual as compared with the known algebraic structures, are studied. It is proved that the set of asymptotic numbers A cannot be isomorphically embedded as a subspace in any group, ring or field, but some particular subsets of asymptotic numbers are shown to be groups, rings, and fields. The algebraic operation, additive and multiplicative forms, and the algebraic properties are constructed in an appropriate way. It is shown that the asymptotic numbers give rise to a new type of generalized functions quite analogous to the distributions of Schwartz allowing, however, the operation multiplication. A possible application of these functions to quantum theory is discussed

  20. Applied number theory

    CERN Document Server

    Niederreiter, Harald

    2015-01-01

    This textbook effectively builds a bridge from basic number theory to recent advances in applied number theory. It presents the first unified account of the four major areas of application where number theory plays a fundamental role, namely cryptography, coding theory, quasi-Monte Carlo methods, and pseudorandom number generation, allowing the authors to delineate the manifold links and interrelations between these areas.  Number theory, which Carl-Friedrich Gauss famously dubbed the queen of mathematics, has always been considered a very beautiful field of mathematics, producing lovely results and elegant proofs. While only very few real-life applications were known in the past, today number theory can be found in everyday life: in supermarket bar code scanners, in our cars’ GPS systems, in online banking, etc.  Starting with a brief introductory course on number theory in Chapter 1, which makes the book more accessible for undergraduates, the authors describe the four main application areas in Chapters...

  1. Precambrian Skeletonized Microbial Eukaryotes

    Science.gov (United States)

    Lipps, Jere H.

    2017-04-01

    . Tintinnids first appear in the mid-Mesozoic, like other modern planktic groups, including planktic foraminifera, new types of radiolarians, and a host of skeletal micro-algae. Microbial eukaryotes track algal eukaryote and metazoan evolution—none or very few in the Precambrian, some in the early Paleozoic with radiations in the later Paleozoic, Mesozoic and Cenozoic, with extinctions ( 30) reducing their biodiversity at particular times in the fossil record—thus indicating strong environmental selection on all marine groups.

  2. RECOVERY OF WHEAT RESIDUE NITROGEN 15 AND RESIDUAL ...

    African Journals Online (AJOL)

    Therefore 85 kg ha-1 N as labelled ammonium sulfate (9.764% atomic excess) was applied in a three-split application. Fertiliser N recovery by wheat in the first year was 33.1%. At harvest, 64.8% of fertiliser N was found in the 0 - 80 cm profile as residual fertiliser-derived N; 2.1% of the applied N could not be accounted for ...

  3. Effect of protein supplementation on ruminal parameters and microbial community fingerprint of Nellore steers fed tropical forages.

    Science.gov (United States)

    Bento, C B P; Azevedo, A C; Gomes, D I; Batista, E D; Rufino, L M A; Detmann, E; Mantovani, H C

    2016-01-01

    In tropical regions, protein supplementation is a common practice in dairy and beef farming. However, the effect of highly degradable protein in ruminal fermentation and microbial community composition has not yet been investigated in a systematic manner. In this work, we aimed to investigate the impact of casein supplementation on volatile fatty acids (VFA) production, specific activity of deamination (SAD), ammonia concentration and bacterial and archaeal community composition. The experimental design was a 4×4 Latin square balanced for residual effects, with four animals (average initial weight of 280±10 kg) and four experimental periods, each with duration of 29 days. The diet comprised Tifton 85 (Cynodon sp.) hay with an average CP content of 9.8%, on a dry matter basis. Animals received basal forage (control) or infusions of pure casein (230 g) administered direct into the rumen, abomasum or divided (50 : 50 ratio) in the rumen/abomasum. There was no differences (P>0.05) in ruminal pH and microbial protein concentration between supplemented v. non-supplemented animals. However, in steers receiving ruminal infusion of casein the SAD and ruminal ammonia concentration increased 33% and 76%, respectively, compared with the control. The total concentration of VFA increased (P0.05) in species richness and diversity of γ-proteobacteria, firmicutes and archaea between non-supplemented Nellore steers and steers receiving casein supplementation in the rumen. However, species richness and the Shannon-Wiener index were lower (P<0.05) for the phylum bacteroidetes in steers supplemented with casein in the rumen compared with non-supplemented animals. Venn diagrams indicated that the number of unique bands varied considerably among individual animals and was usually higher in number for non-supplemented steers compared with supplemented animals. These results add new knowledge about the effects of ruminal and postruminal protein supplementation on metabolic activities of

  4. Microbial Metagenomics: Beyond the Genome

    Science.gov (United States)

    Gilbert, Jack A.; Dupont, Christopher L.

    2011-01-01

    Metagenomics literally means “beyond the genome.” Marine microbial metagenomic databases presently comprise ˜400 billion base pairs of DNA, only ˜3% of that found in 1 ml of seawater. Very soon a trillion-base-pair sequence run will be feasible, so it is time to reflect on what we have learned from metagenomics. We review the impact of metagenomics on our understanding of marine microbial communities. We consider the studies facilitated by data generated through the Global Ocean Sampling expedition, as well as the revolution wrought at the individual laboratory level through next generation sequencing technologies. We review recent studies and discoveries since 2008, provide a discussion of bioinformatic analyses, including conceptual pipelines and sequence annotation and predict the future of metagenomics, with suggestions of collaborative community studies tailored toward answering some of the fundamental questions in marine microbial ecology.

  5. Microbial processes in coastal pollution

    International Nuclear Information System (INIS)

    Capone, D.G.; Bauer, J.E.

    1992-01-01

    In this chapter, the authors describe the nature and range of some of the interactions that can occur between the microbiota and environmental contaminants in coastal areas. The implications of such interactions are also discussed. Pollutant types include inorganic nutrients, heavy metals, bulk organics, organic contaminants, pathogenic microorganisms and microbial pollutants. Both the effects of pollutants such as petroleum hydrocarbons on natural microbial populations and the mitigation of contaminant effects by complexation and biodegradation are considered. Finally, several areas of emerging concerns are presented that involve a confluence of biogeochemistry, microbial ecology and applied and public health microbiology. These concerns range in relevance from local/regional to oceanic/global scales. 308 ref

  6. Residual methamphetamine in decontaminated clandestine drug laboratories.

    Science.gov (United States)

    Patrick, Glen; Daniell, William; Treser, Charles

    2009-03-01

    This pilot cross-sectional study examined three previously decontaminated residential clandestine drug laboratories (CDLs) in Washington State to determine the distribution and magnitude of residual methamphetamine concentrations relative to the state decontamination standard. A total of 159 discrete random methamphetamine wipe samples were collected from the three CDLs, focusing on the master bedroom, bathroom, living room, and kitchen at each site. Additional samples were collected from specific non-random locations likely to be contacted by future residents (e.g., door knobs and light switches). Samples were analyzed for methamphetamine by EPA method 8270 for semivolatile organic chemicals. Overall, 59% of random samples and 75% of contact point samples contained methamphetamine in excess of the state decontamination standard (0.1 micro g/100 cm(2)). At each site, methamphetamine concentrations were generally higher and more variable in rooms where methamphetamine was prepared and used. Even compared with the less stringent standard adopted in Colorado (0.5 micro g/100cm(2)), a substantial number of samples at each site still demonstrated excessive residual methamphetamine (random samples, 25%; contact samples, 44%). Independent oversight of CDL decontamination in residential structures is warranted to protect public health. Further research on the efficacy of CDL decontamination procedures and subsequent verification of methods is needed.

  7. Proficiency test on the determination of pesticide residues in grapes with multi-residue methods.

    Science.gov (United States)

    Dehouck, Pieter; Grimalt, Susana; Dabrio, Marta; Cordeiro, Fernando; Fiamegos, Yiannis; Robouch, Piotr; Fernández-Alba, Amadeo R; de la Calle, Beatriz

    2015-05-22

    This manuscript presents the results of the International Measurement Evaluation Programme 37 (IMEP-37) study, a proficiency test (PT) which was organised to assess the world-wide performance of food control laboratories on the determination of pesticide residues in grapes. This PT supports the implementation of Regulation (EC) No 396/2005 on maximum residue levels of pesticides in or on food and feed of plant and animal origin. Eighty-one participants reported results, forty from EU Member States and forty-one from outside the EU. The test item was a grape sample spiked with 20 selected pesticides. The results of the participants were rated with z- and zeta (ζ-) scores in accordance with ISO 13528 and ISO 17043. The standard deviation for the proficiency assessment, σˆ, of this PT was set at 25% for the 20 measured pesticides based on previous experience with similar measurands. The results reported to IMEP-37 showed that the participants performed satisfactorily, ranging from 81% (carbendazim) to 97% (azoxystrobin, penconazole, pyrimethanil) of the participating laboratories. However, only 30% of the participants managed to analyze all pesticides satisfactorily. Overall, the performance of the participants in this PT was good but there is room for improvement in the development of multi-residue methods for the simultaneous analysis of a large number of pesticides with an increased accuracy. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  8. DEFECT MONITORING IN IRON CASTING USING RESIDUES OF AUTOREGRESSIVE MODELS

    Directory of Open Access Journals (Sweden)

    Vanusa Andrea Casarin

    2013-06-01

    Full Text Available The purpose of this study is to monitor the index of general waste irons forecasting nodular and gray using the residues originated from the methodology Box & Jenkins by means of X-bar and R control charts. Search is to find a general class of model ARIMA (p, d, q but as data have autocorrelation is found to the number of residues which allowed the application of charts. The found model was the model SARIMA (0,1,1(0,1,1 . In step of checking the stability of the model was found that some comments are out of control due to temperature and chemical composition.

  9. Hotspots of soil N2O emission enhanced through water absorption by plant residue

    Energy Technology Data Exchange (ETDEWEB)

    Kravchenko, A.N.; Toosi, E.R.; Guber, A.K.; Ostrom, N.E.; Yu, J.; Azeem, K.; Rivers, M.L.; Robertson , G.P. (UAF Pakistan); (UC); (Hubei); (MSU)

    2017-06-05

    N2O is a highly potent greenhouse gas and arable soils represent its major anthropogenic source. Field-scale assessments and predictions of soil N2O emission remain uncertain and imprecise due to the episodic and microscale nature of microbial N2O production, most of which occurs within very small discrete soil volumes. Such hotspots of N2O production are often associated with decomposing plant residue. Here we quantify physical and hydrological soil characteristics that lead to strikingly accelerated N2O emissions in plant residue-induced hotspots. Results reveal a mechanism for microscale N2O emissions: water absorption by plant residue that creates unique micro-environmental conditions, markedly different from those of the bulk soil. Moisture levels within plant residue exceeded those of bulk soil by 4–10-fold and led to accelerated N2O production via microbial denitrification. The presence of large (Ø >35 μm) pores was a prerequisite for maximized hotspot N2O production and for subsequent diffusion to the atmosphere. Understanding and modelling hotspot microscale physical and hydrologic characteristics is a promising route to predict N2O emissions and thus to develop effective mitigation strategies and estimate global fluxes in a changing environment.

  10. Assessing food allergy risks from residual peanut protein in highly refined vegetable oil

    NARCIS (Netherlands)

    Blom, W.M.; Kruizinga, A.G.; Rubingh, C.M.; Remington, B.C.; Crevel, R.W.R.; Houben, G.F.

    2017-01-01

    Refined vegetable oils including refined peanut oil are widely used in foods. Due to shared production processes, refined non-peanut vegetable oils can contain residual peanut proteins. We estimated the predicted number of allergic reactions to residual peanut proteins using probabilistic risk

  11. Universality of human microbial dynamics

    Science.gov (United States)

    Bashan, Amir; Gibson, Travis E.; Friedman, Jonathan; Carey, Vincent J.; Weiss, Scott T.; Hohmann, Elizabeth L.; Liu, Yang-Yu

    2016-06-01

    Human-associated microbial communities have a crucial role in determining our health and well-being, and this has led to the continuing development of microbiome-based therapies such as faecal microbiota transplantation. These microbial communities are very complex, dynamic and highly personalized ecosystems, exhibiting a high degree of inter-individual variability in both species assemblages and abundance profiles. It is not known whether the underlying ecological dynamics of these communities, which can be parameterized by growth rates, and intra- and inter-species interactions in population dynamics models, are largely host-independent (that is, universal) or host-specific. If the inter-individual variability reflects host-specific dynamics due to differences in host lifestyle, physiology or genetics, then generic microbiome manipulations may have unintended consequences, rendering them ineffective or even detrimental. Alternatively, microbial ecosystems of different subjects may exhibit universal dynamics, with the inter-individual variability mainly originating from differences in the sets of colonizing species. Here we develop a new computational method to characterize human microbial dynamics. By applying this method to cross-sectional data from two large-scale metagenomic studies—the Human Microbiome Project and the Student Microbiome Project—we show that gut and mouth microbiomes display pronounced universal dynamics, whereas communities associated with certain skin sites are probably shaped by differences in the host environment. Notably, the universality of gut microbial dynamics is not observed in subjects with recurrent Clostridium difficile infection but is observed in the same set of subjects after faecal microbiota transplantation. These results fundamentally improve our understanding of the processes that shape human microbial ecosystems, and pave the way to designing general microbiome-based therapies.

  12. Soil-Borne Microbial Functional Structure across Different Land Uses

    Directory of Open Access Journals (Sweden)

    Eiko E. Kuramae

    2014-01-01

    Full Text Available Land use change alters the structure and composition of microbial communities. However, the links between environmental factors and microbial functions are not well understood. Here we interrogated the functional structure of soil microbial communities across different land uses. In a multivariate regression tree analysis of soil physicochemical properties and genes detected by functional microarrays, the main factor that explained the different microbial community functional structures was C : N ratio. C : N ratio showed a significant positive correlation with clay and soil pH. Fields with low C : N ratio had an overrepresentation of genes for carbon degradation, carbon fixation, metal reductase, and organic remediation categories, while fields with high C : N ratio had an overrepresentation of genes encoding dissimilatory sulfate reductase, methane oxidation, nitrification, and nitrogen fixation. The most abundant genes related to carbon degradation comprised bacterial and fungal cellulases; bacterial and fungal chitinases; fungal laccases; and bacterial, fungal, and oomycete polygalacturonases. The high number of genes related to organic remediation was probably driven by high phosphate content, while the high number of genes for nitrification was probably explained by high total nitrogen content. The functional gene diversity found in different soils did not group the sites accordingly to land management. Rather, the soil factors, C : N ratio, phosphate, and total N, were the main factors driving the differences in functional genes across the fields examined.

  13. Targeted Proteomics Approaches To Monitor Microbial Activity In Basalt Aquifer

    Science.gov (United States)

    Paszczynski, A. J.; Paidisetti, R.

    2007-12-01

    communities to allow for better identification of specific proteins. This method not only identified the proteins of interest but also increased the peptide coverage and increased the number of proteins identified. We were able to identify methane monooxygenase proteins within TAN site microbial communities supporting the occurrence of co-metabolic oxidation of TCE in this aquifer. We correlated methane monooxygenase presence with the number of methanotrophs in the samples obtained through quantitative PCR and quantitative proteomic methods. Utilization of this extraction method in combination with UPLC/MS/MS resulted in successful extraction, identification, and quantification of MMO-derived biomarker peptides from both pure cultures and environmental samples. Along with MMO proteins, we identified proteins from non-methanotrophic organisms that may play major roles in macronutrients turnover and the attenuation of TCE in the TAN aquifer.

  14. Marine sponges as microbial fermenters.

    Science.gov (United States)

    Hentschel, Ute; Usher, Kayley M; Taylor, Michael W

    2006-02-01

    The discovery of phylogenetically complex, yet highly sponge-specific microbial communities in marine sponges, including novel lineages and even candidate phyla, came as a surprise. At the same time, unique research opportunities opened up, because the microorganisms of sponges are in many ways more accessible than those of seawater. Accordingly, we consider sponges as microbial fermenters that provide exciting new avenues in marine microbiology and biotechnology. This review covers recent findings regarding diversity, biogeography and population dynamics of sponge-associated microbiota, and the data are discussed within the larger context of the microbiology of the ocean.

  15. Systems biology of Microbial Communities

    Energy Technology Data Exchange (ETDEWEB)

    Navid, A; Ghim, C; Fenley, A; Yoon, S; Lee, S; Almaas, E

    2008-04-11

    Microbes exist naturally in a wide range of environments, spanning the extremes of high acidity and high temperature to soil and the ocean, in communities where their interactions are significant. We present a practical discussion of three different approaches for modeling microbial communities: rate equations, individual-based modeling, and population dynamics. We illustrate the approaches with detailed examples. Each approach is best fit to different levels of system representation, and they have different needs for detailed biological input. Thus, this set of approaches is able to address the operation and function of microbial communities on a wide range of organizational levels.

  16. Invitation to number theory

    CERN Document Server

    Ore, Oystein

    2017-01-01

    Number theory is the branch of mathematics concerned with the counting numbers, 1, 2, 3, … and their multiples and factors. Of particular importance are odd and even numbers, squares and cubes, and prime numbers. But in spite of their simplicity, you will meet a multitude of topics in this book: magic squares, cryptarithms, finding the day of the week for a given date, constructing regular polygons, pythagorean triples, and many more. In this revised edition, John Watkins and Robin Wilson have updated the text to bring it in line with contemporary developments. They have added new material on Fermat's Last Theorem, the role of computers in number theory, and the use of number theory in cryptography, and have made numerous minor changes in the presentation and layout of the text and the exercises.

  17. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Jørgensen, Claus Bjørn; Suetens, Sigrid; Tyran, Jean-Robert

    numbers based on recent drawings. While most players pick the same set of numbers week after week without regards of numbers drawn or anything else, we find that those who do change, act on average in the way predicted by the law of small numbers as formalized in recent behavioral theory. In particular......We investigate the “law of small numbers” using a unique panel data set on lotto gambling. Because we can track individual players over time, we can measure how they react to outcomes of recent lotto drawings. We can therefore test whether they behave as if they believe they can predict lotto......, on average they move away from numbers that have recently been drawn, as suggested by the “gambler’s fallacy”, and move toward numbers that are on streak, i.e. have been drawn several weeks in a row, consistent with the “hot hand fallacy”....

  18. Microbial Biofilm as a Smart Material

    Directory of Open Access Journals (Sweden)

    Christian Garde

    2015-02-01

    Full Text Available Microbial biofilm colonies will in many cases form a smart material capable of responding to external threats dependent on their size and internal state. The microbial community accordingly switches between passive, protective, or attack modes of action. In order to decide which strategy to employ, it is essential for the biofilm community to be able to sense its own size. The sensor designed to perform this task is termed a quorum sensor, since it only permits collective behaviour once a sufficiently large assembly of microbes have been established. The generic quorum sensor construct involves two genes, one coding for the production of a diffusible signal molecule and one coding for a regulator protein dedicated to sensing the signal molecules. A positive feedback in the signal molecule production sets a well-defined condition for switching into the collective mode. The activation of the regulator involves a slow dimerization, which allows low-pass filtering of the activation of the collective mode. Here, we review and combine the model components that form the basic quorum sensor in a number of Gram-negative bacteria, e.g., Pseudomonas aeruginosa.

  19. Computational modeling of synthetic microbial biofilms.

    Science.gov (United States)

    Rudge, Timothy J; Steiner, Paul J; Phillips, Andrew; Haseloff, Jim

    2012-08-17

    Microbial biofilms are complex, self-organized communities of bacteria, which employ physiological cooperation and spatial organization to increase both their metabolic efficiency and their resistance to changes in their local environment. These properties make biofilms an attractive target for engineering, particularly for the production of chemicals such as pharmaceutical ingredients or biofuels, with the potential to significantly improve yields and lower maintenance costs. Biofilms are also a major cause of persistent infection, and a better understanding of their organization could lead to new strategies for their disruption. Despite this potential, the design of synthetic biofilms remains a major challenge, due to the complex interplay between transcriptional regulation, intercellular signaling, and cell biophysics. Computational modeling could help to address this challenge by predicting the behavior of synthetic biofilms prior to their construction; however, multiscale modeling has so far not been achieved for realistic cell numbers. This paper presents a computational method for modeling synthetic microbial biofilms, which combines three-dimensional biophysical models of individual cells with models of genetic regulation and intercellular signaling. The method is implemented as a software tool (CellModeller), which uses parallel Graphics Processing Unit architectures to scale to more than 30,000 cells, typical of a 100 μm diameter colony, in 30 min of computation time.

  20. Soil microbial activities and its relationship with soil chemical ...

    African Journals Online (AJOL)

    The fields assessed are organically managed Soils (OMS), Inorganically Managed Soils (IMS) and an Uncultivated Land having grass coverage (ULS). Soil Microbial Respiration (SMR), Microbial Biomass Carbon (MBC), Microbial Biomass Nitrogen (MBN) and Microbial Biomass Phosphorus (MBP) were analyzed.

  1. Microbial Bioreactor Development in the ALS NSCORT

    Science.gov (United States)

    Mitchell, Cary; Whitaker, Dawn; Banks, M. Katherine; Heber, Albert J.; Turco, Ronald F.; Nies, Loring F.; Alleman, James E.; Sharvelle, Sybil E.; Li, Congna; Heller, Megan

    The NASA Specialized Center of Research and Training in Advanced Life Support (the ALS NSCORT), a partnership of Alabama A & M, Howard, and Purdue Universities, was established by NASA in 2002 to develop technologies that will reduce the Equivalent System Mass (ESM) of regenerative processes within future space life-support systems. A key focus area of NSCORT research has been the development of efficient microbial bioreactors for treatment of human, crop, and food-process wastes while enabling resource recovery. The approach emphasizes optimizing the energy-saving advantages of hydrolytic enzymes for biomass degradation, with focus on treatment of solid wastes including crop residue, paper, food, and human metabolic wastes, treatment of greywater, cabin air, off-gases from other treatment systems, and habitat condensate. This summary includes important findings from those projects, status of technology development, and recommendations for next steps. The Plant-based Anaerobic-Aerobic Bioreactor-Linked Operation (PAABLO) system was developed to reduce crop residue while generating energy and/or food. Plant residues initially were added directly to the bioreactor, and recalcitrant residue was used as a substrate for growing plants or mushrooms. Subsequently, crop residue was first pretreated with fungi to hydrolyze polymers recalcitrant to bacteria, and leachate from the fungal beds was directed to the anaerobic digester. Exoenzymes from the fungi pre-soften fibrous plant materials, improving recovery of materials that are more easily biodegraded to methane that can be used for energy reclamation. An Autothermal Thermophilic Aerobic Digestion (ATAD) system was developed for biodegradable solid wastes. Objectives were to increase water and nutrient recovery, reduce waste volume, and inactivate pathogens. Operational parameters of the reactor were optimized for degradation and resource recovery while minimizing system requirements and footprint. The start-up behavior

  2. The simple complex numbers

    OpenAIRE

    Zalesny, Jaroslaw

    2008-01-01

    A new simple geometrical interpretation of complex numbers is presented. It differs from their usual interpretation as points in the complex plane. From the new point of view the complex numbers are rather operations on vectors than points. Moreover, in this approach the real, imaginary and complex numbers have similar interpretation. They are simply some operations on vectors. The presented interpretation is simpler, more natural, and better adjusted to possible applications in geometry and ...

  3. The microbial community in decaying fallen logs varies with critical period in an alpine forest.

    Science.gov (United States)

    Chang, Chenhui; Wu, Fuzhong; Yang, Wanqin; Xu, Zhenfeng; Cao, Rui; He, Wei; Tan, Bo; Justine, Meta Francis

    2017-01-01

    Little information has been available on the shifts in the microbial community in decaying fallen logs during critical periods in cold forests. Minjiang fir (Abies faxoniana) fallen logs in decay classes I-V were in situ incubated on the forest floor of an alpine forest in the eastern Tibet Plateau. The microbial community was investigated during the seasonal snow cover period (SP), snow thawing period (TP), early growing season (EG) and late growing season (LG) using Phosphorous Lipid Fatty Acid (PLFA) analysis. Total microbial biomass and microbial diversity in fallen logs were much more affected by critical period than decay class, whereas decay class had a stronger effect on microbial diversity than on microbial biomass. Abundant microbial biomass and microbial diversity in logs even without the cover of snow were observed in winter, which could not be linked to thermal insulation by snow cover. The freshly decayed logs functioned as an excellent buffer of environmental variation for microbial organisms during the sharp fluctuations in temperature in winter. We also found distinct decay patterns along with seasonality for heartwood, sapwood and bark, which requires further detailed research. Gram- bacteria mainly dominated the shifts in microbial community composition from SP to EG, while fungi and Gram+ bacteria mainly dominated it from SP to TP. Based on previous work and the present study, we conclude that fallen logs on the forest floor alter ecological processes by influencing microbial communities on woody debris and beneath the soil and litter. Our study also emphasizes the need to maintain a number of fallen logs, especially fresh ones, on the forest floor.

  4. Microbial stratification and microbially catalyzed processes along a hypersaline chemocline

    Science.gov (United States)

    Hyde, A.; Joye, S. B.; Teske, A.

    2017-12-01

    Orca Basin is the largest deep hypersaline anoxic basin in the world, covering over 400 km2. Located at the bottom of the Gulf of Mexico, this body of water reaches depths of 200 meters and is 8 times denser (and more saline) than the overlying seawater. The sharp pycnocline prevents any significant vertical mixing and serves as a particle trap for sinking organic matter. These rapid changes in salinity, oxygen, organic matter, and other geochemical parameters present unique conditions for the microbial communities present. We collected samples in 10m intervals throughout the chemocline. After filtering the water, we used high-throughput bacterial and archaeal 16S rRNA gene sequencing to characterize the changing microbial community along the Orca Basin chemocline. The results reveal a dominance of microbial taxa whose biogeochemical function is entirely unknown. We then used metagenomic sequencing and reconstructed genomes for select samples, revealing the potential dominant metabolic processes in the Orca Basin chemocline. Understanding how these unique geochemical conditions shape microbial communities and metabolic capabilities will have implications for the ocean's biogeochemical cycles and the consequences of expanding oxygen minimum zones.

  5. Pattern of microbial isolates and microbial sensitivity among HIV ...

    African Journals Online (AJOL)

    MJP

    2015-04-18

    Apr 18, 2015 ... sensitivity among HIV positive pregnant women with asymptomatic bacteriuria in Zaria, Nigeria. Methods: This ... asymptomatic, HIV positive pregnant women were screened for bacteriuria out of the 240 eligible women who ... Key words: HIV, Asymptomatic bacteriuria, Microbial isolates, mid-stream urine,.

  6. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Suetens, Sigrid; Galbo-Jørgensen, Claus B.; Tyran, Jean-Robert Karl

    2016-01-01

    as formalized in recent behavioral theory. In particular, players tend to bet less on numbers that have been drawn in the preceding week, as suggested by the ‘gambler’s fallacy’, and bet more on a number if it was frequently drawn in the recent past, consistent with the ‘hot-hand fallacy’.......We investigate the ‘law of small numbers’ using a data set on lotto gambling that allows us to measure players’ reactions to draws. While most players pick the same set of numbers week after week, we find that those who do change react on average as predicted by the law of small numbers...

  7. Intuitive numbers guide decisions

    Directory of Open Access Journals (Sweden)

    Ellen Peters

    2008-12-01

    Full Text Available Measuring reaction times to number comparisons is thought to reveal a processing stage in elementary numerical cognition linked to internal, imprecise representations of number magnitudes. These intuitive representations of the mental number line have been demonstrated across species and human development but have been little explored in decision making. This paper develops and tests hypotheses about the influence of such evolutionarily ancient, intuitive numbers on human decisions. We demonstrate that individuals with more precise mental-number-line representations are higher in numeracy (number skills consistent with previous research with children. Individuals with more precise representations (compared to those with less precise representations also were more likely to choose larger, later amounts over smaller, immediate amounts, particularly with a larger proportional difference between the two monetary outcomes. In addition, they were more likely to choose an option with a larger proportional but smaller absolute difference compared to those with less precise representations. These results are consistent with intuitive number representations underlying: a perceived differences between numbers, b the extent to which proportional differences are weighed in decisions, and, ultimately, c the valuation of decision options. Human decision processes involving numbers important to health and financial matters may be rooted in elementary, biological processes shared with other species.

  8. Beurling generalized numbers

    CERN Document Server

    Diamond, Harold G; Cheung, Man Ping

    2016-01-01

    "Generalized numbers" is a multiplicative structure introduced by A. Beurling to study how independent prime number theory is from the additivity of the natural numbers. The results and techniques of this theory apply to other systems having the character of prime numbers and integers; for example, it is used in the study of the prime number theorem (PNT) for ideals of algebraic number fields. Using both analytic and elementary methods, this book presents many old and new theorems, including several of the authors' results, and many examples of extremal behavior of g-number systems. Also, the authors give detailed accounts of the L^2 PNT theorem of J. P. Kahane and of the example created with H. L. Montgomery, showing that additive structure is needed for proving the Riemann hypothesis. Other interesting topics discussed are propositions "equivalent" to the PNT, the role of multiplicative convolution and Chebyshev's prime number formula for g-numbers, and how Beurling theory provides an interpretation of the ...

  9. Numbers, sequences and series

    CERN Document Server

    Hirst, Keith

    1994-01-01

    Number and geometry are the foundations upon which mathematics has been built over some 3000 years. This book is concerned with the logical foundations of number systems from integers to complex numbers. The author has chosen to develop the ideas by illustrating the techniques used throughout mathematics rather than using a self-contained logical treatise. The idea of proof has been emphasised, as has the illustration of concepts from a graphical, numerical and algebraic point of view. Having laid the foundations of the number system, the author has then turned to the analysis of infinite proc

  10. The adventure of numbers

    CERN Document Server

    Godefroy, Gilles

    2004-01-01

    Numbers are fascinating. The fascination begins in childhood, when we first learn to count. It continues as we learn arithmetic, algebra, geometry, and so on. Eventually, we learn that numbers not only help us to measure the world, but also to understand it and, to some extent, to control it. In The Adventure of Numbers, Gilles Godefroy follows the thread of our expanding understanding of numbers to lead us through the history of mathematics. His goal is to share the joy of discovering and understanding this great adventure of the mind. The development of mathematics has been punctuated by a n

  11. Microbial Heat Recovery Cell (MHRC) System Concept

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-09-01

    This factsheet describes a project that aimed to develop a microbial heat recovery cell (MHRC) system that combines a microbial reverse electrodialysis technology with waste heat recovery to convert industrial effluents into electricity and hydrogen.

  12. Quorum sensing and microbial drug resistance.

    Science.gov (United States)

    Chen, Yu-fan; Liu, Shi-yin; Liang, Zhi-bin; Lv, Ming-fa; Zhou, Jia-nuan; Zhang, Lian-hui

    2016-10-20

    Microbial drug resistance has become a serious problem of global concern, and the evolution and regulatory mechanisms of microbial drug resistance has become a hotspot of research in recent years. Recent studies showed that certain microbial resistance mechanisms are regulated by quorum sensing system. Quorum sensing is a ubiquitous cell-cell communication system in the microbial world, which associates with cell density. High-density microbial cells produce sufficient amount of small signal molecules, activating a range of downstream cellular processes including virulence and drug resistance mechanisms, which increases bacterial drug tolerance and causes infections on host organisms. In this review, the general mechanisms of microbial drug resistance and quorum-sensing systems are summarized with a focus on the association of quorum sensing and chemical signaling systems with microbial drug resistance mechanisms, including biofilm formation and drug efflux pump. The potential use of quorum quenching as a new strategy to control microbial resistance is also discussed.

  13. Microbial quality of a marine tidal pool

    CSIR Research Space (South Africa)

    Genthe, Bettina

    1995-01-01

    Full Text Available In this study the source of microbial pollution to a tidal pool was investigated. Both adjacent seawater which could contribute to possible faecal pollution and potential direct bather pollution were studied. The microbial quality of the marine...

  14. Microbial O2 consumption in the Aespoe tunnel

    International Nuclear Information System (INIS)

    Kotelnikova, S.; Pedersen, Karsten

    1998-04-01

    The report presents data on microbial O 2 reduction activities by microorganisms obtained with different techniques: Winkler method, gas chromatography, most probable numbering, enrichment technique, inhibitor analysis and radiotracer measurements. The samples were collected from boreholes and open funnel ponds at Aespoe in 1996-1998. The evaluation of the microbial activities in open ponds predicts the future microbial activities after the O 2 intrusion around the future repository. The metabolic potential of the microbial population inhabiting groundwater was evaluated on the basis of electron donors available and microbial 16S rRNA gene diversity. The contribution of different microbial groups to the O 2 reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O 2 reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O 2 reduction confirming the biogenic nature of the reduction. The populations developed O 2 reduction rates and capacity depending on the initial concentration of dissolved O 2 reduction. Rates of O 2 reduction ranged from 0.32 to 4.5 μM/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 μM of dissolved O 2 ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O 2 both at 30 deg C and 60 deg C. At 16 deg C no delay in O 2 consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O 2 . Some bacteria use Hg or CH 4 as electron donor instead of organic matter, which means that microbial O 2 reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH 4 oxidation rates ranged between 3.00 and 220 nM CH 4 per litre per day. Comparison of the total O 2 reducing activities by gas chromatography and

  15. Microbial O{sub 2} consumption in the Aespoe tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Kotelnikova, S.; Pedersen, Karsten [Goeteborg Univ. (Sweden). Dept. of Cell and Molecular Biology, Microbiology

    1998-04-01

    The report presents data on microbial O{sub 2} reduction activities by microorganisms obtained with different techniques: Winkler method, gas chromatography, most probable numbering, enrichment technique, inhibitor analysis and radiotracer measurements. The samples were collected from boreholes and open funnel ponds at Aespoe in 1996-1998. The evaluation of the microbial activities in open ponds predicts the future microbial activities after the O{sub 2} intrusion around the future repository. The metabolic potential of the microbial population inhabiting groundwater was evaluated on the basis of electron donors available and microbial 16S rRNA gene diversity. The contribution of different microbial groups to the O{sub 2} reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O{sub 2} reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O{sub 2} reduction confirming the biogenic nature of the reduction. The populations developed O{sub 2} reduction rates and capacity depending on the initial concentration of dissolved O{sub 2} reduction. Rates of O{sub 2} reduction ranged from 0.32 to 4.5 {mu}M/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 {mu}M of dissolved O{sub 2} ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O{sub 2} both at 30 deg C and 60 deg C. At 16 deg C no delay in O{sub 2} consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O{sub 2}. Some bacteria use Hg or CH{sub 4} as electron donor instead of organic matter, which means that microbial O{sub 2} reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH{sub 4} oxidation rates ranged between 3.00 and 220 nM CH{sub 4} per litre per

  16. Calcination/dissolution residue treatment

    International Nuclear Information System (INIS)

    Knight, R.C.; Creed, R.F.; Patello, G.K.; Hollenberg, G.W.; Buehler, M.F.; O'Rourke, S.M.; Visnapuu, A.; McLaughlin, D.F.

    1994-09-01

    Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination

  17. Multi-residue methods for confirmatory determination of antibiotics in milk.

    Science.gov (United States)

    Samanidou, Victoria; Nisyriou, Styliani

    2008-06-01

    The prevalent use of antibiotics, e. g. sulphonamides, tetracyclines, beta-lactams, macrolides, aminoglycosides, etc., in dairy farming to prevent and treat microbial infections e. g. mastitis, can be a potential source of veterinary drug residues in milk. Antibiotic residues constitute a risk to human health, since they can cause allergic reactions in hypersensitive individuals or they may lead to the appearance of drug-resistant bacteria. Analysis of these residues plays a key role in ensuring food safety. Regulatory agencies in the European Union and in other countries have established maximum residue limits and requirements concerning the performance of analytical methods and the interpretation of the results. This review describes the state of the art in the analytical strategies concerning the multi-class as well as the multi-residue analysis of antibiotics in milk. Since milk is a complex matrix due to its high protein and fat content, which often interfere in analytical procedures, special focus has been placed on sample preparation: extraction and clean-up. Confirmation of antibiotic residues according to European Decision 657/2002/EC has been also discussed.

  18. The potential for constructed wetlands to treat alkaline bauxite-residue leachate: Phragmites australis growth.

    Science.gov (United States)

    Higgins, D; Curtin, T; Pawlett, M; Courtney, R

    2016-12-01

    High alkalinity (pH > 12) of bauxite-residue leachates presents challenges for the long-term storage and managements of the residue. Recent evidence has highlighted the potential for constructed wetlands to effectively buffer the alkalinity, but there is limited evidence on the potential for wetland plants to establish and grow in soils inundated with residue leachate. A pot-based trial was conducted to investigate the potential for Phragmites australis to establish and grow in substrate treated with residue leachate over a pH range of 8.6-11.1. The trial ran for 3 months, after which plant growth and biomass were determined. Concentrations of soluble and exchangeable trace elements in the soil substrate and also in the aboveground and belowground biomass were determined. Residue leachate pH did not affect plant biomass or microbial biomass. With the exception of Na, there was no effect on exchangeable trace elements in the substrate; however, increases in soluble metals (As, Cd and Na) were observed with increasing leachate concentration. Furthermore, increases in Al, As and V were observed in belowground biomass and for Cd and Cr in aboveground biomass. Concentrations within the vegetation biomass were less than critical phytotoxic levels. Results demonstrate the ability for P. australis to grow in bauxite-residue leachate-inundated growth media without adverse effects.

  19. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    NARCIS (Netherlands)

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

  20. Simulation of Weld Mechanical Behavior to Include Welding-Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes

    Science.gov (United States)

    2015-11-01

    Memorandum Simulation of Weld Mechanical Behavior to Include Welding-Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes...Weld Mechanical Behavior to Include Welding-Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes by Charles R. Fisher...Welding- Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes 5a. CONTRACT NUMBER N/A 5b. GRANT NUMBER N/A 5c

  1. Effects of application of corn straw on soil microbial community structure during the maize growing season.

    Science.gov (United States)

    Lu, Ping; Lin, Yin-Hua; Yang, Zhong-Qi; Xu, Yan-Peng; Tan, Fei; Jia, Xu-Dong; Wang, Miao; Xu, De-Rong; Wang, Xi-Zhuo

    2015-01-01

    This study investigated the influence of corn straw application on soil microbial communities and the relationship between such communities and soil properties in black soil. The crop used in this study was maize (Zea mays L.). The five treatments consisted of applying a gradient (50, 100, 150, and 200%) of shattered corn straw residue to the soil. Soil samples were taken from May through September during the 2012 maize growing season. The microbial community structure was determined using phospholipid fatty acid (PLFA) analysis. Our results revealed that the application of corn straw influenced the soil properties and increased the soil organic carbon and total nitrogen. Applying corn straw to fields also influenced the variation in soil microbial biomass and community composition, which is consistent with the variations found in soil total nitrogen (TN) and soil respiration (SR). However, the soil carbon-to-nitrogen ratio had no effect on soil microbial communities. The abundance of PLFAs, TN, and SR was higher in C1.5 than those in other treatments, suggesting that the soil properties and soil microbial community composition were affected positively by the application of corn straw to black soil. A Principal Component Analysis indicated that soil microbial communities were different in the straw decomposition processes. Moreover, the soil microbial communities from C1.5 were significantly different from those of CK (p soil and significant variations in the ratio of monounsaturated-to-branched fatty acids with different straw treatments that correlated with SR (p soil properties and soil microbial communities and that these properties affect these communities. The individual PLFA signatures were sensitive indicators that reflected the changes in the soil environment condition. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The impact of synthetic pyrethroid and organophosphate sheep dip formulations on microbial activity in soil

    Energy Technology Data Exchange (ETDEWEB)

    Boucard, Tatiana K.; McNeill, Charles [Department of Environmental Science, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Bardgett, Richard D. [Department of Biological Sciences, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Paynter, Christopher D. [Department of Environmental Science, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Semple, Kirk T. [Department of Environmental Science, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YQ (United Kingdom)], E-mail: k.semple@lancaster.ac.uk

    2008-05-15

    Sheep dip formulations containing organophosphates (OPs) or synthetic pyrethroids (SPs) have been widely used in UK, and their spreading onto land has been identified as the most practical disposal method. In this study, the impact of two sheep dip formulations on the microbial activity of a soil was investigated over a 35-d incubation. Microbial utilisation of [1-{sup 14}C] glucose, uptake of {sup 14}C-activity into the microbial biomass and microbial numbers (CFUs g{sup -1} soil) were investigated. In control soils and soils amended with 0.01% sheep dip, after 7 d a larger proportion of added glucose was allocated to microbial biomass rather than respired to CO{sub 2}. No clear temporal trends were found in soils amended with 0.1% and 1% sheep dips. Both sheep dip formulations at 0.1% and 1% concentrations resulted in a significant increase in CFUs g{sup -1} soil and [1-{sup 14}C] glucose mineralisation rates, as well as a decline in microbial uptake of [1-{sup 14}C] glucose, compared to control and 0.01% SP- or OP-amended soils. This study suggests that the growth, activity, physiological status and/or structure of soil microbial community may be affected by sheep dips. - The application of sheep dip formulations can have a profound impact upon microbial activity and substrate utilisation in soil.

  3. Substrate specificity of microbial transglutaminase as revealed by three-dimensional docking simulation and mutagenesis

    OpenAIRE

    Tagami, Uno; Shimba, Nobuhisa; Nakamura, Mina; Yokoyama, Kei-ichi; Suzuki, Ei-ichiro; Hirokawa, Takatsugu

    2009-01-01

    Transglutaminases (TGases) are used in fields such as food and pharmaceuticals. Unlike other TGases, microbial transglutaminase (MTG) activity is Ca2+-independent, broadening its application. Here, a three-dimensional docking model of MTG binding to a peptide substrate, CBZ-Gln-Gly, was simulated. The data reveal CBZ-Gln-Gly to be stretched along the MTG active site cleft with hydrophobic and/or aromatic residues interacting directly with the substrate. Moreover, an oxyanion binding site for ...

  4. Residual strain mapping of Roman styli from Iulia Concordia, Italy

    International Nuclear Information System (INIS)

    Salvemini, Filomena; Grazzi, Francesco; Angelini, Ivana; Davydov, Vadim; Vontobel, Peter; Vigoni, Alberto; Artioli, Gilberto; Zoppi, Marco

    2014-01-01

    Iulia Concordia is an important Roman settlement known for the production of iron objects and weapons during the Roman Empire. A huge number of well-preserved styli were found in the past century in the bed of an old channel. In order to shed light about the production processes used by Roman for stylus manufacturing, a neutron diffraction residual strain analysis was performed on the POLDI materials science diffractometer at the Paul Scherrer Institut in Switzerland. Here, we present results from our investigation conducted on 11 samples, allowing to define, in a non-invasive way, the residual strain map related to the ancient Roman working techniques. - Highlights: • We examined 11 Roman styli from the settlement of Iulia Concordia, Italy. • We performed a neutron diffraction residual strain analysis on POLDI at PSI (CH). • We identified the production processes used by Roman for stylus manufacturing. • We clarified the way and direction of working applied for different classes of styli

  5. Residual strain mapping of Roman styli from Iulia Concordia, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Salvemini, Filomena, E-mail: floriana.salvemini@fi.isc.cnr.it [Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Sesto Fiorentino, FI (Italy); Università degli Studi di Firenze, Dipartimento di Scienze della Terra (Italy); Grazzi, Francesco [Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Sesto Fiorentino, FI (Italy); Angelini, Ivana [Università degli Studi di Padova, Dipartimento di Geoscienze (Italy); Davydov, Vadim; Vontobel, Peter [Paul Scherrer Institut, SINQ Spallation Neutron Source, Villigen (Switzerland); Vigoni, Alberto [Dedalo s.n.c., Vicolo dei Conti 6, I-35122 Padua (Italy); Artioli, Gilberto [Università degli Studi di Padova, Dipartimento di Geoscienze (Italy); Zoppi, Marco [Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Sesto Fiorentino, FI (Italy)

    2014-05-01

    Iulia Concordia is an important Roman settlement known for the production of iron objects and weapons during the Roman Empire. A huge number of well-preserved styli were found in the past century in the bed of an old channel. In order to shed light about the production processes used by Roman for stylus manufacturing, a neutron diffraction residual strain analysis was performed on the POLDI materials science diffractometer at the Paul Scherrer Institut in Switzerland. Here, we present results from our investigation conducted on 11 samples, allowing to define, in a non-invasive way, the residual strain map related to the ancient Roman working techniques. - Highlights: • We examined 11 Roman styli from the settlement of Iulia Concordia, Italy. • We performed a neutron diffraction residual strain analysis on POLDI at PSI (CH). • We identified the production processes used by Roman for stylus manufacturing. • We clarified the way and direction of working applied for different classes of styli.

  6. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass-Spectrometry (MALDI-TOF MS Based Microbial Identifications: Challenges and Scopes for Microbial Ecologists

    Directory of Open Access Journals (Sweden)

    Parveen Rahi

    2016-08-01

    Full Text Available Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS based biotyping is an emerging technique for high-throughput and rapid microbial identification. Due to its relatively higher accuracy, comprehensive database of clinically important microorganisms and low-cost compared to other microbial identification methods, MALDI-TOF MS has started replacing existing practices prevalent in clinical diagnosis. However, applicability of MALDI-TOF MS in the area of microbial ecology research is still limited mainly due to the lack of data on non-clinical microorganisms. Intense research activities on cultivation of microbial diversity by conventional as well as by innovative and high-throughput methods has substantially increased the number of microbial species known today. This important area of research is in urgent need of rapid and reliable method(s for characterization and de-replication of microorganisms from various ecosystems. MALDI-TOF MS based characterization, in our opinion, appears to be the most suitable technique for such studies. Reliability of MALDI-TOF MS based identification method depends mainly on accuracy and width of reference databases, which need continuous expansion and improvement. In this review, we propose a common strategy to generate MALDI-TOF MS spectral database and advocated its sharing, and also discuss the role of MALDI-TOF MS based high-throughput microbial identification in microbial ecology studies.

  7. The Class Number Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 7. The Class Number Problem - An Introduction to Algebraic Number Theory. Rajat Tandon. General ... Author Affiliations. Rajat Tandon1. Department of Mathematics, University of Hyderabad, Central University P.O., Hyderabad 500 046, India ...

  8. The Class Number Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 7. The Class Number Problem - An Introduction to Algebraic Number Theory. Rajat Tandon. General Article Volume 3 Issue 7 July 1998 pp 28-37. Fulltext. Click here to view fulltext PDF. Permanent link:

  9. The Class Number Problem

    Indian Academy of Sciences (India)

    The Class Number Problem. 2. An Introduction to Algebraic Number Theory. Rajat Tandon received his PhD from Yale. University, USA. After an initial period as a visiting post-doctoral fellow at. TIFR, he joined the faculty of the North. Eastern Hill University, where he taught for a few years. For about two decades now, he ...

  10. A Numbers Game

    DEFF Research Database (Denmark)

    Levin, Bruce R; McCall, Ingrid C.; Perrot, Veronique

    2017-01-01

    We postulate that the inhibition of growth and low rates of mortality of bacteria exposed to ribosome-binding antibiotics deemed bacteriostatic can be attributed almost uniquely to these drugs reducing the number of ribosomes contributing to protein synthesis, i.e., the number of effective riboso...

  11. The Congruent Number Problem

    Indian Academy of Sciences (India)

    Given a positive integer n, is there a simple criterion which enables us to decide whether or not n is congruent? A few remarks are in order. To start with, if we ..... In other words 1 is a congruent number. Combining Propositions 2 and 3 with the fact that 1 is a non-congruent number, we deduce Fermat's last theorem for n=4.

  12. Templates, Numbers & Watercolors.

    Science.gov (United States)

    Clemesha, David J.

    1990-01-01

    Describes how a second-grade class used large templates to draw and paint five-digit numbers. The lesson integrated artistic knowledge and vocabulary with their mathematics lesson in place value. Students learned how draftspeople use templates, and they studied number paintings by Charles Demuth and Jasper Johns. (KM)

  13. Operating conditions influence microbial community structures, elimination of the antibiotic resistance genes and metabolites during anaerobic digestion of cow manure in the presence of oxytetracycline.

    Science.gov (United States)

    Turker, Gokhan; Akyol, Çağrı; Ince, Orhan; Aydin, Sevcan; Ince, Bahar

    2018-01-01

    The way that antibiotic residues in manure follow is one of the greatest concerns due to its potential negative impacts on microbial communities, the release of metabolites and antibiotic resistant genes (ARGs) into the nature and the loss of energy recovery in anaerobic digestion (AD) systems. This study evaluated the link between different operating conditions, the biodegradation of oxytetracycline (OTC) and the formation of its metabolites and ARGs in anaerobic digesters treating cow manure. Microbial communities and ARGs were determined through the use of quantitative real-time PCR. The biodegradation of OTC and occurrence of metabolites were determined using UV-HPLC and LC/MS/MS respectively. The maximum quantity of resistance genes was also examined at the beginning of AD tests and concentration was in the order of: tetM >tetO. The numbers of ARGs were always higher at high volatile solids (VS) content and high mixing rate. The results of the investigation revealed that relationship between mixing rate and VS content plays a crucial role for elimination of ARGs, OTC and metabolites. This can be attributed to high abundance of microorganisms due to high VS content and their increased contact with elevated mixing rate. An increased interaction between microorganisms triggers the promotion of ARGs. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Microbially produced phytotoxins and plant disease management ...

    African Journals Online (AJOL)

    Nowadays, these evaluation techniques are becoming an important complement to classical breeding methods. The knowledge of the inactivation of microbial toxins has led to the use of microbial enzymes to inactivate phytotoxins thereby reducing incidence and severity of disease induced by microbial toxins. Considering ...

  15. In situ microbial filter used for bioremediation

    Science.gov (United States)

    Carman, M. Leslie; Taylor, Robert T.

    2000-01-01

    An improved method for in situ microbial filter bioremediation having increasingly operational longevity of an in situ microbial filter emplaced into an aquifer. A method for generating a microbial filter of sufficient catalytic density and thickness, which has increased replenishment interval, improved bacteria attachment and detachment characteristics and the endogenous stability under in situ conditions. A system for in situ field water remediation.

  16. Microbial incorporation of nitrogen in stream detritus

    Science.gov (United States)

    Diane M. Sanzone; Jennifer L. Tank; Judy L. Meyer; Patrick J. Mulholland; Stuart E.G. Findlay

    2001-01-01

    We adapted the chloroform fumigation method to determine microbial nitrogen (N) and microbial incorporation of 15N on three common substrates [leaves, wood and fine benthic organic matter (FBOM)] in three forest streams. We compared microbial N and 15 content of samples collected during a 6-week15N-NH...

  17. Characterisation and management of concrete grinding residuals.

    Science.gov (United States)

    Kluge, Matt; Gupta, Nautasha; Watts, Ben; Chadik, Paul A; Ferraro, Christopher; Townsend, Timothy G

    2018-02-01

    Concrete grinding residue is the waste product resulting from the grinding, cutting, and resurfacing of concrete pavement. Potential beneficial applications for concrete grinding residue include use as a soil amendment and as a construction material, including as an additive to Portland cement concrete. Concrete grinding residue exhibits a high pH, and though not hazardous, it is sufficiently elevated that precautions need to be taken around aquatic ecosystems. Best management practices and state regulations focus on reducing the impact on such aquatic environment. Heavy metals are present in concrete grinding residue, but concentrations are of the same magnitude as typically recycled concrete residuals. The chemical composition of concrete grinding residue makes it a useful product for some soil amendment purposes at appropriate land application rates. The presence of unreacted concrete in concrete grinding residue was examined for potential use as partial replacement of cement in new concrete. Testing of Florida concrete grinding residue revealed no dramatic reactivity or improvement in mortar strength.

  18. Polychlorinated Biphenyls (PCB) Residue Effects Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — The PCB Residue Effects (PCBRes) Database was developed to assist scientists and risk assessors in correlating PCB and dioxin-like compound residues with toxic...

  19. Interpretation on Recycling Plastics from Shredder Residue

    Science.gov (United States)

    EPA is considering an interpretation of its regulations that would generally allow for recycling of plastic separated from shredder residue under the conditions described in the Voluntary Procedures for Recycling Plastics from Shredder Residue.

  20. Advanced Microscopy of Microbial Cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy...

  1. Advanced microscopy of microbial cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy...

  2. Microbial communities in blueberry soils

    Science.gov (United States)

    Microbial communities thrive in the soil of the plant root zone and it is clear that these communities play a role in plant health. Although blueberry fields can be productive for decades, yields are sometimes below expectations and fields that are replanted sometimes underperform and/or take too lo...

  3. Hypersaline Microbial Mat Lipid Biomarkers

    Science.gov (United States)

    Jahnke, Linda L.; Embaye, Tsegereda; Turk, Kendra A.; Summons, Roger E.

    2002-01-01

    Lipid biomarkers and compound specific isotopic abundances are powerful tools for studies of contemporary microbial ecosystems. Knowledge of the relationship of biomarkers to microbial physiology and community structure creates important links for understanding the nature of early organisms and paleoenvironments. Our recent work has focused on the hypersaline microbial mats in evaporation ponds at Guerrero Negro, Baja California Sur, Mexico. Specific biomarkers for diatoms, cyanobacteria, archaea, green nonsulfur (GNS), sulfate reducing, sulfur oxidizing and methanotrophic bacteria have been identified. Analyses of the ester-bound fatty acids indicate a highly diverse microbial community, dominated by photosynthetic organisms at the surface. The delta C-13 of cyanobacterial biomarkers such as the monomethylalkanes and hopanoids are consistent with the delta C-13 measured for bulk mat (-10%o), while a GNS biomarker, wax esters (WXE), suggests a more depleted delta C-13 for GNS biomass (-16%o). This isotopic relationship is different than that observed in mats at Octopus Spring, Yellowstone National Park (YSNP) where GNS appear to grow photoheterotrophic ally. WXE abundance, while relatively low, is most pronounced in an anaerobic zone just below the cyanobacterial layer. The WXE isotope composition at GN suggests that these bacteria utilize photoautotrophy incorporating dissolved inorganic carbon (DIC) via the 3-hydroxypropionate pathway using H2S or H2.

  4. Towards a microbial thermoelectric cell.

    Directory of Open Access Journals (Sweden)

    Raúl Rodríguez-Barreiro

    Full Text Available Microbial growth is an exothermic process. Biotechnological industries produce large amounts of heat, usually considered an undesirable by-product. In this work, we report the construction and characterization of the first microbial thermoelectric cell (MTC, in which the metabolic heat produced by a thermally insulated microbial culture is partially converted into electricity through a thermoelectric device optimized for low ΔT values. A temperature of 41°C and net electric voltage of around 250-600 mV was achieved with 1.7 L baker's yeast culture. This is the first time microbial metabolic energy has been converted into electricity with an ad hoc thermoelectric device. These results might contribute towards developing a novel strategy to harvest excess heat in the biotechnology industry, in processes such as ethanol fermentation, auto thermal aerobic digestion (ATAD or bioremediation, which could be coupled with MTCs in a single unit to produce electricity as a valuable by-product of the primary biotechnological product. Additionally, we propose that small portable MTCs could be conceived and inoculated with suitable thermophilic of hyperthermophilic starter cultures and used for powering small electric devices.

  5. The microbial contribution to macroecology

    Science.gov (United States)

    Barberán, Albert; Casamayor, Emilio O.; Fierer, Noah

    2014-01-01

    There has been a recent explosion of research within the field of microbial ecology that has been fueled, in part, by methodological improvements that make it feasible to characterize microbial communities to an extent that was inconceivable only a few years ago. Furthermore, there is increasing recognition within the field of ecology that microorganisms play a critical role in the health of organisms and ecosystems. Despite these developments, an important gap still persists between the theoretical framework of macroecology and microbial ecology. We highlight two idiosyncrasies of microorganisms that are fundamental to understanding macroecological patterns and their mechanistic drivers. First, high dispersal rates provide novel opportunities to test the relative importance of niche, stochastic, and historical processes in structuring biological communities. Second, high speciation rates potentially lead to the convergence of ecological and evolutionary time scales. After reviewing these unique aspects, we discuss strategies for improving the conceptual integration of microbes into macroecology. As examples, we discuss the use of phylogenetic ecology as an integrative approach to explore patterns across the tree of life. Then we demonstrate how two general theories of biodiversity (i.e., the recently developed theory of stochastic geometry and the neutral theory) can be adapted to microorganisms. We demonstrate how conceptual models that integrate evolutionary and ecological mechanisms can contribute to the unification of microbial ecology and macroecology. PMID:24829564

  6. Advanced Microscopy of Microbial Cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    Growing awareness of heterogeneity in cells of microbial populations has emphasized the importance of advanced microscopy for visualization and understanding of the molecular mechanisms underlying cell-to-cell variation. In this review, we highlight some of the recent advances in confocal...... for visualization of variation between cells in phenotypic traits such as gene expression....

  7. Life Support Systems Microbial Challenges

    Science.gov (United States)

    Roman, Monsi C.

    2010-01-01

    Many microbiological studies were performed during the development of the Space Station Water Recovery and Management System from1990-2009. Studies include assessments of: (1) bulk phase (planktonic) microbial population (2) biofilms, (3) microbially influenced corrosion (4) biofouling treatments. This slide presentation summarizes the studies performed to assess the bulk phase microbial community during the Space Station Water Recovery Tests (WRT) from 1990 to 1998. This report provides an overview of some of the microbiological analyses performed during the Space Station WRT program. These tests not only integrated several technologies with the goal of producing water that met NASA s potable water specifications, but also integrated humans, and therefore human flora into the protocols. At the time these tests were performed, not much was known (or published) about the microbial composition of these types of wastewater. It is important to note that design changes to the WRS have been implemented over the years and results discussed in this report might be directly related to test configurations that were not chosen for the final flight configuration. Results microbiological analyses performed Conclusion from the during the WRT showed that it was possible to recycle water from different sources, including urine, and produce water that can exceed the quality of municipally produced water.

  8. Monitoring residue in animals and primary products of animal origin

    Directory of Open Access Journals (Sweden)

    Janković Saša

    2008-01-01

    Full Text Available The objective of control and systematic monitoring of residue is to secure, by the examination of a corresponding number of samples, the efficient monitoring of the residue level in tissues and organs of animals, as well as in primary products of animal origin. This creates possibilities for the timely taking of measures toward the securing of food hygiene of animal origin and the protection of public health. Residue can be a consequence of the inadequate use of medicines in veterinary medicine and pesticides in agriculture and veterinary medicine, as well as the polluting of the environment with toxic elements, dioxins, polychlorinated biphenyls, and others. Residue is being monitored in Serbia since 1972, and in 2004, national monitoring was brought to the level of EU countries through significant investments by the Ministry of Agriculture, Forestry and Water Management. This is also evident in the EU directives which permit exports of all kinds of meat and primary products of animal origin, covered by the Residue Monitoring Program. The program of systematic examinations of residue has been coordinated with the requirements of the European Union, both according to the type of examined substance, as well as according to the number of samples and the applied analytical techniques. In addition to the development of methods and the including of new harmful substances into the monitoring programme, it is also necessary to coordinate the national regulations that define the maximum permitted quantities of certain medicines and contaminants with the EU regulations, in order to protect the health of consumers as efficiently as possible, and for the country to take equal part in international trade.

  9. On the residual stress modeling of shot-peened AISI 4340 steel: finite element and response surface methods

    Science.gov (United States)

    Asgari, Ali; Dehestani, Pouya; Poruraminaie, Iman

    2018-02-01

    Shot peening is a well-known process in applying the residual stress on the surface of industrial parts. The induced residual stress improves fatigue life. In this study, the effects of shot peening parameters such as shot diameter, shot speed, friction coefficient, and the number of impacts on the applied residual stress will be evaluated. To assess these parameters effect, firstly the shot peening process has been simulated by finite element method. Then, effects of the process parameters on the residual stress have been evaluated by response surface method as a statistical approach. Finally, a strong model is presented to predict the maximum residual stress induced by shot peening process in AISI 4340 steel. Also, the optimum parameters for the maximum residual stress are achieved. The results indicate that effect of shot diameter on the induced residual stress is increased by increasing the shot speed. Also, enhancing the friction coefficient magnitude always cannot lead to increase in the residual stress.

  10. Pesticide dissipation and microbial community changes in a biopurification system: influence of the rhizosphere.

    Science.gov (United States)

    Diez, M C; Elgueta, S; Rubilar, O; Tortella, G R; Schalchli, H; Bornhardt, C; Gallardo, F

    2017-12-01

    The dissipation of atrazine, chlorpyrifos and iprodione in a biopurification system and changes in the microbial and some biological parameters influenced by the rhizosphere of Lolium perenne were studied in a column system packed with an organic biomixture. Three column depths were analyzed for residual pesticides, peroxidase, fluorescein diacetate activity and microbial communities. Fungal colonization was analyzed by confocal laser scanning microscopy to assess the extent of its proliferation in wheat straw. The L. perenne rhizosphere enhanced pesticide dissipation and negligible pesticide residues were detected at 20-30 cm column depth. Atrazine, chlorpyrifos and iprodione removal was 82, 89 and 74% respectively in the first 10 cm depth for columns with vegetal cover. The presence of L. perenne in contaminated columns stimulated peroxidase activity in all three column depth sections. Fluorescein diacetate activity decreased over time in all column sections with the highest values in biomixtures with vegetal cover. Microbial communities, analyzed by PCR-DGGE, were not affected by the pesticide mixture application, presenting high values of similarity (>65%) with and without vegetal cover. Microbial abundance of Actinobacteria varied according to treatment and no clear link was observed. However, bacterial abundance increased over time and was similar with and without vegetal cover. On the other hand, fungal abundance decreased in all sections of columns after 40 days, but an increase was observed in response to pesticide application. Fungal colonization and straw degradation during pesticide dissipation were verified by monitoring the lignin autofluorescence loss.

  11. Plant genotype, microbial recruitment and nutritional security.

    Science.gov (United States)

    Patel, Jai S; Singh, Akanksha; Singh, Harikesh B; Sarma, Birinchi K

    2015-01-01

    Agricultural food products with high nutritional value should always be preferred over food products with low nutritional value. Efforts are being made to increase nutritional value of food by incorporating dietary supplements to the food products. The same is more desirous if the nutritional value of food is increased under natural environmental conditions especially in agricultural farms. Fragmented researches have demonstrated possibilities in achieving the same. The rhizosphere is vital in this regard for not only health and nutritional status of plants but also for the microorganisms colonizing the rhizosphere. Remarkably robust composition of plant microbiome with respect to other soil environments clearly suggests the role of a plant host in discriminating its colonizers (Zancarini et al., 2012). A large number of biotic and abiotic factors are believed to manipulate the microbial communities in the rhizosphere. However, plant genotype has proven to be the key in giving the final shape of the rhizosphere microbiome (Berendsen et al., 2012; Marques et al., 2014).

  12. Review on the Influences of Bagging Treatment on Pesticide Residue in Fruits

    Directory of Open Access Journals (Sweden)

    ZHAO Xiao-yun

    2018-02-01

    Full Text Available At present, bagging technology has been widely applicated in fruit cultivation. Impact of bagging treatment on the pesticide residues have different results. On the basis of existing achievements, this paper systematically analyzed the influence of different bagging treatments on pesticide residues:such as different ways of applying pesticide, pesticide concentration, number of applying pesticide; bagging materials, bagged layer; the type of pesticide(systemic pesticide, nonendoscopic pesticide; different portions of the fruit, crop varieties and so on. The way of applying pesticide had great impact on pesticide residue, pesticide application after bagging could largely reduce the pesticide residue, and pesticide application before bagging could increase pesticide residues; The four factors including pesticide appliacation dosage, the type of pesticides and fruit portion and fruit varieties on the effects of pesticide residues, had interaction each other. The pesticide applying several times, bagging could significantly reduce pesticide residues and control within the security level. Different bagging materials could reduce pesticide residues, but the impact on pesticide residues had no significant difference. More bagging layers caused less pesticide residues.

  13. Effect of residual stress on the integrity of a branch connection

    International Nuclear Information System (INIS)

    Law, M.; Kirstein, O.; Luzin, V.

    2012-01-01

    A new connection to an existing gas pipeline was made by hot-tapping, welding directly onto a pressurised pipeline. The welds were not post-weld heat treated, causing significant residual stresses. The critical weld had residual stresses determined by neutron diffraction using ANSTO's residual stress diffractometer, Kowari. The maximum measured residual stress (290 MPa) was 60% of the yield strength. The magnitudes of errors from a number of sources were estimated. An integrity assessment of the welded branch connection was performed with the measured residual stress values and with residual stress distributions from the BS 7910 and API 579 analysis codes. Analysis using estimates of residual stress from API 579 overestimated the critical crack size. Highlights: ► Residual stresses were measured by neutron diffraction in a thick section, non post-weld heat treated ferritic weld. ► There is little published data on these welds. ► The work compares the measured residual stresses with code-based residual stress distributions.

  14. Continuous enzyme-coupled assay for microbial transglutaminase activity.

    Science.gov (United States)

    Oteng-Pabi, Samuel K; Keillor, Jeffrey W

    2013-10-15

    Transglutaminases (protein-glutamine:amine γ-glutamyltransferase, EC 2.3.2.13) are a family of calcium-dependent enzymes that catalyze an acyl transfer between glutamine residues and a wide variety of primary amines. When a lysine residue acts as the acyl-acceptor substrate, a γ-glutamyl-ε-lysine isopeptide bond is formed. This isopeptide bond formation represents protein cross-linking, which is critical to several biological processes. Microbial transglutaminase (mTG) is a bacterial variant of the transglutaminase family, distinct by virtue of its calcium-independent catalysis of the isopeptidic bond formation. Furthermore, mTG's promiscuity in acyl-acceptor substrate preference highlights its biocatalytic potential. The acyl-donor substrate, however, is limited in its scope; the amino acid sequences flanking glutamine residues dramatically affect substrate specificity and activity. Here, we have developed and optimized a modified glutamate dehydrogenase assay with the intention of analyzing potential high-affinity peptides. This direct continuous assay presents significant advantages over the commonly used hydroxamate assay, including generality, sensitivity, and ease of manipulation. Furthermore, we identified 7M48 (WALQRPH), a high-affinity peptide that shows greater affinity with mTG (K(M)=3 mM) than the commonly used Cbz-Gln-Gly (K(M)=58 mM), attesting to its potential for application in biocatalysis and bioconjugation. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Residual Analysis of Generalized Autoregressive Integrated Moving ...

    African Journals Online (AJOL)

    In this study, analysis of residuals of generalized autoregressive integrated moving average bilinear time series model was considered. The adequacy of this model was based on testing the estimated residuals for whiteness. Jarque-Bera statistic and squared-residual autocorrelations were used to test the estimated ...

  16. 9 CFR 311.39 - Biological residues.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues. ...

  17. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1995-01-01

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

  18. Neutron residual stress measurements in linepipe

    Science.gov (United States)

    Law, Michael; Gnaëpel-Herold, Thomas; Luzin, Vladimir; Bowie, Graham

    2006-11-01

    Residual stresses in gas pipelines are generated by manufacturing and construction processes and may affect the subsequent pipe integrity. In the present work, the residual stresses in eight samples of linepipe were measured by neutron diffraction. Residual stresses changed with some coating processes. This has special implications in understanding and mitigating stress corrosion cracking, a major safety and economic problem in some gas pipelines.

  19. Neutron residual stress measurements in linepipe

    International Nuclear Information System (INIS)

    Law, Michael; Gnaepel-Herold, Thomas; Luzin, Vladimir; Bowie, Graham

    2006-01-01

    Residual stresses in gas pipelines are generated by manufacturing and construction processes and may affect the subsequent pipe integrity. In the present work, the residual stresses in eight samples of linepipe were measured by neutron diffraction. Residual stresses changed with some coating processes. This has special implications in understanding and mitigating stress corrosion cracking, a major safety and economic problem in some gas pipelines

  20. Glycogen is large molecules wherein Glucose residues

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Glycogen is large molecules wherein Glucose residues. Glycogen is large molecules wherein Glucose residues. linked by α-(1- 4) glycosidic bonds into chains and chains. branch via α-(1- 6) linkage. Branching points are about every fourth residue – allows. glucose ...

  1. Comparative Genome Analysis in the Integrated Microbial Genomes(IMG) System

    Energy Technology Data Exchange (ETDEWEB)

    Kyrpides, Nikos C.; Markowitz, Victor M.

    2006-03-01

    Comparative genome analysis is critical for the effectiveexploration of a rapidly growing number of complete and draft sequencesfor microbial genomes. The Integrated Microbial Genomes (IMG) system(img.jgi.doe.gov) has been developed as a community resource thatprovides support for comparative analysis of microbial genomes in anintegrated context. IMG allows users to navigate the multidimensionalmicrobial genome data space and focus their analysis on a subset ofgenes, genomes, and functions of interest. IMG provides graphicalviewers, summaries and occurrence profile tools for comparing genes,pathways and functions (terms) across specific genomes. Genes can befurther examined using gene neighborhoods and compared with sequencealignment tools.

  2. Elementary number theory

    CERN Document Server

    Dudley, Underwood

    2008-01-01

    Ideal for a first course in number theory, this lively, engaging text requires only a familiarity with elementary algebra and the properties of real numbers. Author Underwood Dudley, who has written a series of popular mathematics books, maintains that the best way to learn mathematics is by solving problems. In keeping with this philosophy, the text includes nearly 1,000 exercises and problems-some computational and some classical, many original, and some with complete solutions. The opening chapters offer sound explanations of the basics of elementary number theory and develop the fundamenta

  3. Numbers and computers

    CERN Document Server

    Kneusel, Ronald T

    2015-01-01

    This is a book about numbers and how those numbers are represented in and operated on by computers. It is crucial that developers understand this area because the numerical operations allowed by computers, and the limitations of those operations, especially in the area of floating point math, affect virtually everything people try to do with computers. This book aims to fill this gap by exploring, in sufficient but not overwhelming detail, just what it is that computers do with numbers. Divided into two parts, the first deals with standard representations of integers and floating point numb

  4. On powerful numbers

    Directory of Open Access Journals (Sweden)

    R. A. Mollin

    1986-01-01

    Full Text Available A powerful number is a positive integer n satisfying the property that p2 divides n whenever the prime p divides n; i.e., in the canonical prime decomposition of n, no prime appears with exponent 1. In [1], S.W. Golomb introduced and studied such numbers. In particular, he asked whether (25,27 is the only pair of consecutive odd powerful numbers. This question was settled in [2] by W.A. Sentance who gave necessary and sufficient conditions for the existence of such pairs. The first result of this paper is to provide a generalization of Sentance's result by giving necessary and sufficient conditions for the existence of pairs of powerful numbers spaced evenly apart. This result leads us naturally to consider integers which are representable as a proper difference of two powerful numbers, i.e. n=p1−p2 where p1 and p2 are powerful numbers with g.c.d. (p1,p2=1. Golomb (op.cit. conjectured that 6 is not a proper difference of two powerful numbers, and that there are infinitely many numbers which cannot be represented as a proper difference of two powerful numbers. The antithesis of this conjecture was proved by W.L. McDaniel [3] who verified that every non-zero integer is in fact a proper difference of two powerful numbers in infinitely many ways. McDaniel's proof is essentially an existence proof. The second result of this paper is a simpler proof of McDaniel's result as well as an effective algorithm (in the proof for explicitly determining infinitely many such representations. However, in both our proof and McDaniel's proof one of the powerful numbers is almost always a perfect square (namely one is always a perfect square when n≢2(mod4. We provide in §2 a proof that all even integers are representable in infinitely many ways as a proper nonsquare difference; i.e., proper difference of two powerful numbers neither of which is a perfect square. This, in conjunction with the odd case in [4], shows that every integer is representable in

  5. Algebraic number theory

    CERN Document Server

    Weiss, Edwin

    1998-01-01

    Careful organization and clear, detailed proofs characterize this methodical, self-contained exposition of basic results of classical algebraic number theory from a relatively modem point of view. This volume presents most of the number-theoretic prerequisites for a study of either class field theory (as formulated by Artin and Tate) or the contemporary treatment of analytical questions (as found, for example, in Tate's thesis).Although concerned exclusively with algebraic number fields, this treatment features axiomatic formulations with a considerable range of applications. Modem abstract te

  6. Brief history of numbers

    CERN Document Server

    Corry, Leo

    2015-01-01

    The world around us is saturated with numbers. They are a fundamental pillar of our modern society, and accepted and used with hardly a second thought. But how did this state of affairs come to be? In this book, Leo Corry tells the story behind the idea of number from the early days of the Pythagoreans, up until the turn of the twentieth century. He presents an overview of how numbers were handled and conceived in classical Greek mathematics, in the mathematics of Islam, in European mathematics of the middle ages and the Renaissance, during the scientific revolution, all the way through to the

  7. Advanced number theory

    CERN Document Server

    Cohn, Harvey

    1980-01-01

    ""A very stimulating book ... in a class by itself."" - American Mathematical MonthlyAdvanced students, mathematicians and number theorists will welcome this stimulating treatment of advanced number theory, which approaches the complex topic of algebraic number theory from a historical standpoint, taking pains to show the reader how concepts, definitions and theories have evolved during the last two centuries. Moreover, the book abounds with numerical examples and more concrete, specific theorems than are found in most contemporary treatments of the subject.The book is divided into three parts

  8. Professor Stewart's incredible numbers

    CERN Document Server

    Stewart, Ian

    2015-01-01

    Ian Stewart explores the astonishing properties of numbers from 1 to10 to zero and infinity, including one figure that, if you wrote it out, would span the universe. He looks at every kind of number you can think of - real, imaginary, rational, irrational, positive and negative - along with several you might have thought you couldn't think of. He explains the insights of the ancient mathematicians, shows how numbers have evolved through the ages, and reveals the way numerical theory enables everyday life. Under Professor Stewart's guidance you will discover the mathematics of codes,

  9. Random number generation

    International Nuclear Information System (INIS)

    Coveyou, R.R.

    1974-01-01

    The subject of random number generation is currently controversial. Differing opinions on this subject seem to stem from implicit or explicit differences in philosophy; in particular, from differing ideas concerning the role of probability in the real world of physical processes, electronic computers, and Monte Carlo calculations. An attempt is made here to reconcile these views. The role of stochastic ideas in mathematical models is discussed. In illustration of these ideas, a mathematical model of the use of random number generators in Monte Carlo calculations is constructed. This model is used to set up criteria for the comparison and evaluation of random number generators. (U.S.)

  10. The emergence of number

    CERN Document Server

    Crossley, John N

    1987-01-01

    This book presents detailed studies of the development of three kinds of number. In the first part the development of the natural numbers from Stone-Age times right up to the present day is examined not only from the point of view of pure history but also taking into account archaeological, anthropological and linguistic evidence. The dramatic change caused by the introduction of logical theories of number in the 19th century is also treated and this part ends with a non-technical account of the very latest developments in the area of Gödel's theorem. The second part is concerned with the deve

  11. Supersymmetric Displaced Number States

    Directory of Open Access Journals (Sweden)

    Fredy R. Zypman

    2015-06-01

    Full Text Available We introduce, generate and study a family of supersymmetric displaced number states (SDNS that can be considered generalized coherent states of the supersymmetric harmonic oscillator. The family is created from the seminal supersymmetric boson-fermion entangling annihilation operator introduced by Aragone and Zypman and later expanded by Kornbluth and Zypman. Using the momentum representation, the states are obtained analytically in compact form as displaced supersymmetric number states. We study their position-momentum uncertainties, and their bunchiness by classifying them according to their Mandel Q-parameter in phase space. We were also able to find closed form analytical representations in the space and number basis.

  12. High Reynolds Number Turbulence

    National Research Council Canada - National Science Library

    Smits, Alexander J

    2007-01-01

    The objectives of the grant were to provide a systematic study to fill the gap between existing research on low Reynolds number turbulent flows to the kinds of turbulent flows encountered on full-scale vehicles...

  13. Really big numbers

    CERN Document Server

    Schwartz, Richard Evan

    2014-01-01

    In the American Mathematical Society's first-ever book for kids (and kids at heart), mathematician and author Richard Evan Schwartz leads math lovers of all ages on an innovative and strikingly illustrated journey through the infinite number system. By means of engaging, imaginative visuals and endearing narration, Schwartz manages the monumental task of presenting the complex concept of Big Numbers in fresh and relatable ways. The book begins with small, easily observable numbers before building up to truly gigantic ones, like a nonillion, a tredecillion, a googol, and even ones too huge for names! Any person, regardless of age, can benefit from reading this book. Readers will find themselves returning to its pages for a very long time, perpetually learning from and growing with the narrative as their knowledge deepens. Really Big Numbers is a wonderful enrichment for any math education program and is enthusiastically recommended to every teacher, parent and grandparent, student, child, or other individual i...

  14. Solar Indices - Sunspot Numbers

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  15. Volume 9 Number 2

    African Journals Online (AJOL)

    OLUWOLE

    Table 1: Insect Invaders Encountered and their Stages at Collection from Decaying. Banana / Plantain Pseudo stems. Insect Order. Family. Genus. Species. Life Stage Encountered. Number (%). Coleoptera. Curculionidae Curculionidae. Curculionidae Curculionidae. Curculionidae Curculionidae. Curculionidae.

  16. Quantum random number generator

    Science.gov (United States)

    Pooser, Raphael C.

    2016-05-10

    A quantum random number generator (QRNG) and a photon generator for a QRNG are provided. The photon generator may be operated in a spontaneous mode below a lasing threshold to emit photons. Photons emitted from the photon generator may have at least one random characteristic, which may be monitored by the QRNG to generate a random number. In one embodiment, the photon generator may include a photon emitter and an amplifier coupled to the photon emitter. The amplifier may enable the photon generator to be used in the QRNG without introducing significant bias in the random number and may enable multiplexing of multiple random numbers. The amplifier may also desensitize the photon generator to fluctuations in power supplied thereto while operating in the spontaneous mode. In one embodiment, the photon emitter and amplifier may be a tapered diode amplifier.

  17. Drawing a random number

    DEFF Research Database (Denmark)

    Wanscher, Jørgen Bundgaard; Sørensen, Majken Vildrik

    2006-01-01

    Random numbers are used for a great variety of applications in almost any field of computer and economic sciences today. Examples ranges from stock market forecasting in economics, through stochastic traffic modelling in operations research to photon and ray tracing in graphics. The construction...... of a model or a solution method requires certain characteristics of the random numbers used. This is usually a distribution classification, which the sequence of random numbers must fulfill; of these some are very hard to fulfill and others are next to impossible. Today mathematics allows us to transform...... highly uniform multidimensional draws, which are highly relevant for todays traffic models. This paper shows among others combined shuffling and scrambling seems needless, that scrambling gives the lowest correlation and that there are detectable differences between random numbers, dependent...

  18. Metal Residue Deposition from Military Pyrotechnic Devices and Field Sampling Guidance

    Science.gov (United States)

    2012-05-01

    Lawrence Livermore National Laboratory, Livermore, CA. Taylor. S. R. 1964. Abundance of chemical elements in the continental crust . Geochimica et...Development Center Cold Regions Research and Engineering Laboratory Hanover, NH 03755 Approved for Public Release; Distribution is Unlimited Metal Residue...TITLE AND SUBTITLE Metal Residue Deposition from Military Pyrotechnic Devices and Field Sampling Guidance 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  19. A family of microbial lysine transporter polypeptides

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention provides a genetically modified microbial cell for production of lysine, comprising a transgene encoding a polypeptide capable of exporting lysine from the cell. The genetically modified microbial cell for production of lysine may be further characterized by genetic modifica......The present invention provides a genetically modified microbial cell for production of lysine, comprising a transgene encoding a polypeptide capable of exporting lysine from the cell. The genetically modified microbial cell for production of lysine may be further characterized by genetic...... a novel family of lysine transporter polypeptides; and the use of said polypeptide to enhance production of extracellular lysine in a microbial cell....

  20. Natural radioactivity in petroleum residues

    International Nuclear Information System (INIS)

    Gazineu, M.H.P.; Gazineu, M.H.P.; Hazin, C.A.; Hazin, C.A.

    2006-01-01

    The oil extraction and production industry generates several types of solid and liquid wastes. Scales, sludge and water are typical residues that can be found in such facilities and that can be contaminated with Naturally Occurring Radioactive Material (N.O.R.M.). As a result of oil processing, the natural radionuclides can be concentrated in such residues, forming the so called Technologically Enhanced Naturally Occurring Radioactive Material, or T.E.N.O.R.M.. Most of the radionuclides that appear in oil and gas streams belong to the 238 U and 232 Th natural series, besides 40 K. The present work was developed to determine the radionuclide content of scales and sludge generated during oil extraction and production operations. Emphasis was given to the quantification of 226 Ra, 228 Ra and 40 K since these radionuclides,are responsible for most of the external exposure in such facilities. Samples were taken from the P.E.T.R.O.B.R.A.S. unity in the State of Sergipe, in Northeastern Brazil. They were collected directly from the inner surface of water pipes and storage tanks, or from barrels stored in the waste storage area of the E and P unit. The activity concentrations for 226 Ra, 228 Ra and 40 K were determined by using an HP Ge gamma spectrometric system. The results showed concentrations ranging from 42.7 to 2,110.0 kBq/kg for 226 Ra, 40.5 to 1,550.0 kBq/kg for 228 Ra, and 20.6 to 186.6 kBq/kg for 40 K. The results highlight the importance of determining the activity concentration of those radionuclides in oil residues before deciding whether they should be stored or discarded to the environment. (authors)

  1. Natural radioactivity in petroleum residues

    Energy Technology Data Exchange (ETDEWEB)

    Gazineu, M.H.P. [UNICAP, Dept. de Quimica, Recife (Brazil); Gazineu, M.H.P.; Hazin, C.A. [UFPE, Dept. de Energia Nuclear, Recife (Brazil); Hazin, C.A. [Centro Regional de Ciencias Nucleares/ CNEN, Recife (Brazil)

    2006-07-01

    The oil extraction and production industry generates several types of solid and liquid wastes. Scales, sludge and water are typical residues that can be found in such facilities and that can be contaminated with Naturally Occurring Radioactive Material (N.O.R.M.). As a result of oil processing, the natural radionuclides can be concentrated in such residues, forming the so called Technologically Enhanced Naturally Occurring Radioactive Material, or T.E.N.O.R.M.. Most of the radionuclides that appear in oil and gas streams belong to the {sup 238}U and {sup 232}Th natural series, besides 40 K. The present work was developed to determine the radionuclide content of scales and sludge generated during oil extraction and production operations. Emphasis was given to the quantification of {sup 226}Ra, {sup 228}Ra and 40 K since these radionuclides,are responsible for most of the external exposure in such facilities. Samples were taken from the P.E.T.R.O.B.R.A.S. unity in the State of Sergipe, in Northeastern Brazil. They were collected directly from the inner surface of water pipes and storage tanks, or from barrels stored in the waste storage area of the E and P unit. The activity concentrations for {sup 226}Ra, {sup 228}Ra and 40 K were determined by using an HP Ge gamma spectrometric system. The results showed concentrations ranging from 42.7 to 2,110.0 kBq/kg for {sup 226}Ra, 40.5 to 1,550.0 kBq/kg for {sup 228}Ra, and 20.6 to 186.6 kBq/kg for 40 K. The results highlight the importance of determining the activity concentration of those radionuclides in oil residues before deciding whether they should be stored or discarded to the environment. (authors)

  2. BiomeNet: a Bayesian model for inference of metabolic divergence among microbial communities.

    OpenAIRE

    Mahdi Shafiei; Katherine A Dunn; Hugh Chipman; Hong Gu; Joseph P Bielawski

    2014-01-01

    Metagenomics yields enormous numbers of microbial sequences that can be assigned a metabolic function. Using such data to infer community-level metabolic divergence is hindered by the lack of a suitable statistical framework. Here, we describe a novel hierarchical Bayesian model, called BiomeNet (Bayesian inference of metabolic networks), for inferring differential prevalence of metabolic subnetworks among microbial communities. To infer the structure of community-level metabolic interactions...

  3. Identification of Microbial Gene Biomarkers for in situ RDX Biodegradation

    Science.gov (United States)

    2012-12-01

    via HGT is significant, for bioaugmentation efforts utilizing xplA-containing bacteria may have the effect of seeding the indigenous microbial...strain MR-1, a phylogenetic gene marker targeting Shewanella may have some benefit since a number of species from this genus transform RDX. ERDC/EL...Members of the genus Gordonia metabolize a variety of aliphatic, aromatic, and halogenated hydrocarbons, benzothiophenes, polyisoprenes, and

  4. Process to recycle shredder residue

    Science.gov (United States)

    Jody, Bassam J.; Daniels, Edward J.; Bonsignore, Patrick V.

    2001-01-01

    A system and process for recycling shredder residue, in which separating any polyurethane foam materials are first separated. Then separate a fines fraction of less than about 1/4 inch leaving a plastics-rich fraction. Thereafter, the plastics rich fraction is sequentially contacted with a series of solvents beginning with one or more of hexane or an alcohol to remove automotive fluids; acetone to remove ABS; one or more of EDC, THF or a ketone having a boiling point of not greater than about 125.degree. C. to remove PVC; and one or more of xylene or toluene to remove polypropylene and polyethylene. The solvents are recovered and recycled.

  5. Residual replacement strategies for Krylov subspace iterative methods for the convergence of true residuals

    NARCIS (Netherlands)

    Vorst, H.A. van der; Ye, Q.

    1999-01-01

    In this paper, a strategy is proposed for alternative computations of the residual vectors in Krylov subspace methods, which improves the agreement of the computed residuals and the true residuals to the level of O(u)kAkkxk. Building on earlier ideas on residual replacement and on insights in

  6. Residual stress measurements of welded stainless steel 304 plate using the HANARO residual stress instrument

    International Nuclear Information System (INIS)

    Mun, M. K.; Lee, C. H.; Em, V. T.

    2001-01-01

    In order to nondestructively measure in-depth residual stress distribution of the metallic materials, it is unique method to use neutron diffraction. In this paper the principles of residual stress measurements by neutron diffraction is described. The residual stress distribution of welded strainless steeel 304 plate using te HANARO residual stress instrument is also described

  7. 40 CFR 721.4500 - Isopropylamine distillation residues and ethylamine distillation residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Isopropylamine distillation residues and ethylamine distillation residues. 721.4500 Section 721.4500 Protection of Environment... residues and ethylamine distillation residues. (a) Chemical substances and significant new use subject to...

  8. Residual analysis for spatial point processes

    DEFF Research Database (Denmark)

    Baddeley, A.; Turner, R.; Møller, Jesper

    process. Residuals are ascribed to locations in the empty background, as well as to data points of the point pattern. We obtain variance formulae, and study standardised residuals. There is also an analogy between our spatial residuals and the usual residuals for (non-spatial) generalised linear models...... or covariate effects. Q-Q plots of the residuals are effective in diagnosing interpoint interaction. Some existing ad hoc statistics of point patterns (quadrat counts, scan statistic, kernel smoothed intensity, Berman's diagnostic) are recovered as special cases....

  9. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1995-01-01

    weeks of decomposition, due to high rates of residue N net mineralization and subsequent leaching and denitrification losses of N. Lysimeter experiments showed that pea residues may reduce leaching losses of N, probably due to their effect on the mineralization-immobilizalion turnover of N...... and denitrification. Winter barley succeeding field pea recovered 13% of the incorporated pea residue N by early December; the recovery was found to be 15% at maturity in July. A spring-sown crop of barley recovered less than half the amount of pea residue N recovered by winter barley. The residue N-use efficiencies...

  10. Toward Understanding, Managing, and Protecting Microbial Ecosystems

    Science.gov (United States)

    Bodelier, Paul L. E.

    2011-01-01

    Microbial communities are at the very basis of life on earth, catalyzing biogeochemical reactions driving global nutrient cycles. However, unlike for plants and animals, microbial diversity is not on the biodiversity–conservation agenda. The latter, however, would imply that microbial diversity is not under any threat by anthropogenic disturbance or climate change. This maybe a misconception caused by the rudimentary knowledge we have concerning microbial diversity and its role in ecosystem functioning. This perspective paper identifies major areas with knowledge gaps within the field of environmental microbiology that preclude a comprehension of microbial ecosystems on the level we have for plants and animals. Opportunities and challenges are pointed out to open the microbial black box and to go from descriptive to predictive microbial ecology. PMID:21747797

  11. Towards understanding, managing and protecting microbial ecosystems

    Directory of Open Access Journals (Sweden)

    Paul eBodelier

    2011-04-01

    Full Text Available Microbial communities are at the very basis of life on earth, catalysing biogeochemical reactions driving global nutrient cycles. However, unlike for plants and animals, microbial diversity is not on the biodiversity conservation agenda. The latter, however, would imply that microbial diversity is not under any threat by anthropogenic disturbance or climate change. This maybe a misconception caused by the rudimentary knowledge we have concerning microbial diversity and its role in ecosystem functioning. This perspective paper indentifies major areas with knowledge gaps within the field of environmental microbiology that preclude a comprehension of microbial ecosystems on the level we have for plants and animals. Opportunities and challenges are pointed out to open the microbial black box and to go from descriptive to predictive microbial ecology.

  12. Toward understanding, managing, and protecting microbial ecosystems.

    Science.gov (United States)

    Bodelier, Paul L E

    2011-01-01

    Microbial communities are at the very basis of life on earth, catalyzing biogeochemical reactions driving global nutrient cycles. However, unlike for plants and animals, microbial diversity is not on the biodiversity-conservation agenda. The latter, however, would imply that microbial diversity is not under any threat by anthropogenic disturbance or climate change. This maybe a misconception caused by the rudimentary knowledge we have concerning microbial diversity and its role in ecosystem functioning. This perspective paper identifies major areas with knowledge gaps within the field of environmental microbiology that preclude a comprehension of microbial ecosystems on the level we have for plants and animals. Opportunities and challenges are pointed out to open the microbial black box and to go from descriptive to predictive microbial ecology.

  13. Microbial Metabolism in Serpentinite Fluids

    Science.gov (United States)

    Crespo-Medina, M.; Brazelton, W. J.; Twing, K. I.; Kubo, M.; Hoehler, T. M.; Schrenk, M. O.

    2013-12-01

    Serpentinization is the process in which ultramafic rocks, characteristic of the upper mantle, react with water liberating mantle carbon and reducing power to potenially support chemosynthetic microbial communities. These communities may be important mediators of carbon and energy exchange between the deep Earth and the surface biosphere. Our work focuses on the Coast Range Ophiolite Microbial Observatory (CROMO) in Northern California where subsurface fluids are accessible through a series of wells. Preliminary analyses indicate that the highly basic fluids (pH 9-12) have low microbial diversity, but there is limited knowledge about the metabolic capabilities of these communties. Metagenomic data from similar serpentine environments [1] have identified Betaproteobacteria belonging to the order Burkholderiales and Gram-positive bacteria from the order Clostridiales as key components of the serpentine microbiome. In an effort to better characterize the microbial community, metabolism, and geochemistry at CROMO, fluids from two representative wells (N08B and CSWold) were sampled during recent field campaigns. Geochemical characterization of the fluids includes measurements of dissolved gases (H2, CO, CH4), dissolved inorganic and organic carbon, volatile fatty acids, and nutrients. The wells selected can be differentiated in that N08B had higher pH (10-11), lower dissolved oxygen, and cell counts ranging from 105-106 cells mL-1 of fluid, with an abundance of the betaproteobacterium Hydrogenophaga. In contrast, fluids from CSWold have slightly lower pH (9-9.5), DO, and conductivity, as well as higher TDN and TDP. CSWold fluid is also characterized for having lower cell counts (~103 cells mL-1) and an abundance of Dethiobacter, a taxon within the phylum Clostridiales. Microcosm experiments were conducted with the purpose of monitoring carbon fixation, methanotrophy and metabolism of small organic compounds, such as acetate and formate, while tracing changes in fluid

  14. Soil microbial attributes treated with composting of sewage sludge

    Directory of Open Access Journals (Sweden)

    Claudio Roberto Silva

    2012-08-01

    Full Text Available The use of sludge composting in agricultural areas alters the microbial functions. In this context it is necessary to evaluate the impact of composting addition on microbial activities in the soil. This study evaluated the alteration of microbial attributes of a soil fertilized with sewage sludge compost by measuring the CO2 release rates and counting bacteria and fungi numbers. This experiment was conducted in laboratory using respirometric jars that contained samples of soil mixed with different doses of compost: 0; 20; 40; 60 and 80 Mg ha-1, and CO2 release was quantified daily during the 28 days of incubation when the samples were removed from the jars and bacteria and fungi quantities were counted. The treatments corresponding to each dose of the composting were arranged in completely randomized design with four replications. The CO2 release and the quantity of bacteria and fungi increased with additional doses of the compound. This occurred as a result of supplying energetic substrate and nutrients from the compound. The CO2 released measurements indicated that compound above 20 Mg ha-1 has significant impact on soil microbial activity.

  15. Electron beam irradiation of Matricaria chamomilla L. for microbial decontamination

    Science.gov (United States)

    Nemţanu, Monica R.; Kikuchi, Irene Satiko; de Jesus Andreoli Pinto, Terezinha; Mazilu, Elena; Setnic, Silvia; Bucur, Marcela; Duliu, Octavian G.; Meltzer, Viorica; Pincu, Elena

    2008-05-01

    Wild chamomile (Matricaria chamomilla L.) is one of the most popular herbal materials with both internal and external use to cure different health disturbances. As a consequence of its origin, chamomile could carry various microbial contaminants which offer different hazards to the final consumer. Reduction of the microbial load to the in force regulation limits represents an important phase in the technological process of vegetal materials, and the electron beam treatment might be an efficient alternative to the classical methods of hygienic quality assurance. The purpose of the study was to analyze the potential application of the electron beam treatment in order to assure the microbial safety of the wild chamomile. Samples of chamomile dry inflorescences were treated in electron beam (e-beam) of 6 MeV mean energy, at room temperature and ambient pressure. Some loss of the chemical compounds with bioactive role could be noticed, but the number of microorganisms decreased as a function on the absorbed dose. Consequently, the microbial quality of studied vegetal material inflorescences was improved by e-beam irradiation.

  16. Electron beam irradiation of Matricaria chamomilla L. for microbial decontamination

    International Nuclear Information System (INIS)

    Nemtanu, Monica R.; Kikuchi, Irene Satiko; Jesus Andreoli Pinto, Terezinha de; Mazilu, Elena; Setnic, Silvia; Bucur, Marcela; Duliu, Octavian G.; Meltzer, Viorica; Pincu, Elena

    2008-01-01

    Wild chamomile (Matricaria chamomilla L.) is one of the most popular herbal materials with both internal and external use to cure different health disturbances. As a consequence of its origin, chamomile could carry various microbial contaminants which offer different hazards to the final consumer. Reduction of the microbial load to the in force regulation limits represents an important phase in the technological process of vegetal materials, and the electron beam treatment might be an efficient alternative to the classical methods of hygienic quality assurance. The purpose of the study was to analyze the potential application of the electron beam treatment in order to assure the microbial safety of the wild chamomile. Samples of chamomile dry inflorescences were treated in electron beam (e-beam) of 6 MeV mean energy, at room temperature and ambient pressure. Some loss of the chemical compounds with bioactive role could be noticed, but the number of microorganisms decreased as a function on the absorbed dose. Consequently, the microbial quality of studied vegetal material inflorescences was improved by e-beam irradiation

  17. Electron beam irradiation of Matricaria chamomilla L. for microbial decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Nemtanu, Monica R. [National Institute for Lasers, Plasma and Radiation Physics, Electron Accelerator Laboratory, 409 Atomistilor Street, P.O. Box MG-36, 077125 Bucharest-Magurele (Romania)], E-mail: monica.nemtanu@inflpr.ro; Kikuchi, Irene Satiko; Jesus Andreoli Pinto, Terezinha de [University of Sao Paulo, Faculty of Pharmaceutical Sciences, Department of Pharmacy, Av. Prof. Lineu Prestes, 580-Bloco 13, Cidade Universitaria, 05508-900 Sao Paulo (Brazil); Mazilu, Elena; Setnic, Silvia [S.C. Hofigal Export-Import S.A., 2A Intrarea Serelor Street, 75669, Bucharest 4 (Romania); Bucur, Marcela [University of Bucharest, Faculty of Biology, Department of Microbiology, 1-3 Aleea Portocalelor Street, Bucharest 6 (Romania); Duliu, Octavian G. [University of Bucharest, Department of Atomic and Nuclear Physics, P.O. Box MG-11, 077125 Bucharest (Romania); Meltzer, Viorica; Pincu, Elena [University of Bucharest, Faculty of Chemistry, Department of Physical Chemistry, Bd. Regina Elisabeta 4-12, 030018 Bucharest (Romania)

    2008-05-15

    Wild chamomile (Matricaria chamomilla L.) is one of the most popular herbal materials with both internal and external use to cure different health disturbances. As a consequence of its origin, chamomile could carry various microbial contaminants which offer different hazards to the final consumer. Reduction of the microbial load to the in force regulation limits represents an important phase in the technological process of vegetal materials, and the electron beam treatment might be an efficient alternative to the classical methods of hygienic quality assurance. The purpose of the study was to analyze the potential application of the electron beam treatment in order to assure the microbial safety of the wild chamomile. Samples of chamomile dry inflorescences were treated in electron beam (e-beam) of 6 MeV mean energy, at room temperature and ambient pressure. Some loss of the chemical compounds with bioactive role could be noticed, but the number of microorganisms decreased as a function on the absorbed dose. Consequently, the microbial quality of studied vegetal material inflorescences was improved by e-beam irradiation.

  18. Algal and microbial exopolysaccharides: new insights as biosurfactants and bioemulsifiers.

    Science.gov (United States)

    Paniagua-Michel, José de Jesús; Olmos-Soto, Jorge; Morales-Guerrero, Eduardo Roberto

    2014-01-01

    Currently, efforts are being made to utilize more natural biological systems as alternatives as a way to replace fossil forms of carbon. There is a growing concern at global level to have nontoxic, nonhazardous surface-active agents; contrary to synthetic surfactants, their biological counterparts or biosurfactants play a primary function, facilitating microbial presence in environments dominated by hydrophilic-hydrophobic interfaces. Algal and microbial biosurfactants/bioemulsifiers from marine and deep-sea environments are attracting major interest due to their structural and functional diversity as molecules actives of surface and an alternative biomass to replace fossil forms of carbon. Algal and microbial surfactants are lipid in nature and classified as glycolipids, phospholipids, lipopeptides, natural lipids, fatty acids, and lipopolysaccharides. These metabolic bioactive products are applicable in a number of industries and processes, viz., food processing, pharmacology, and bioremediation of oil-polluted environments. This chapter presents an update of the progress and potentialities of the principal producers of exopolysaccharide (EPS)-type biosurfactants and bioemulsifiers, viz., macro- and microalgae (cyanobacteria and diatoms) and bacteria from marine and extreme environments. Particular interest is centered into new sources and applications, viz., marine and deep-sea environments and promissory uses of these EPSs as biosurfactants/emulsifiers and other polymeric roles. The enormous benefits of these molecules encourage their discovery, exploitation, and development of new microbial EPSs that could possess novel industrial importance and corresponding innovations. © 2014 Elsevier Inc. All rights reserved.

  19. Conditional Dependence in Microbial Forensic Assays - A Primer

    Energy Technology Data Exchange (ETDEWEB)

    Velsko, Stephan P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-11-08

    This report provides an introduction to the topic of conditional dependence in the context of microbial forensic assays. Conditional dependence between two items of evidence E1 and E2 occurs when they are both used to support a hypothesis, but E1 affects the probability of E2 and vice versa. Ignoring this dependence can lead to very large errors in estimating the diagnosticity of the combined evidence. To introduce readers to this concept, a number of definitions of conditional dependence that have been used by authors in the past have been collected together and compared. Formal mathematical relationships that constrain conditional dependence are summarized. There are several specific scenarios in which unrecognized conditional dependence can arise in microbial forensic contexts. This report provides some notional examples that illustrate dramatic effects of conditional dependence on the weight of microbial forensic evidence, and discusses the relevance of these observations for the validation of microbial forensic assays. A two-­parameter model that describes the transition between various limiting forms of conditional dependence relations is provided in an appendix.

  20. Performance optimization and microbiological analysis of microbial fuel cell

    Directory of Open Access Journals (Sweden)

    Yajun WANG

    2016-06-01

    Full Text Available In order to improve the operation performance of microbial fuel cells, improved the degradation rate of nitrate and the power output of microbial fuel cell, a typical single chamber air-cathode microbial fuel cell (AC-MFC is inoculated and operated with urban sewage treatment plant clarifier sludge as inoculum source and sodium nitrate as electron acceptor. It is successfully started by synthetic wastewater containing a phosphate buffered nutrient solution (PBS, 50 mmol/L and sodium acetate (1 g/L. After successful starting, the four factors of carbon source, C/N, nitrate concentration and temperature are considered to optimize the operation performance of MFC. The test result shows that the operation performance of MFC is best under the conditions of anhydrous sodium acetate as carbon source, C/N of 5∶1, 200 mg/L nitrate concentration and at 30 ℃, and the degradation rate of nitrate reaches more than 90% and the voltage of MFC is 0.462 V. After 6 cycles of operation, the voltage and power density of MFC reaches 0.62 V and 4.53 W /m2. AC impedance analysis indicates that the MFC resistance is 130 Ω. Scanning electron microscopy of electrode surface illustrates that the number of microbial species are significantly increased. The results indicate that MFC can be an effective technology for nitrate contained wastewater treatment and energy production.